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Friends:  Informed commentary from the Weather Underground - living with =
uncertainty


    Hurricane Watches Are Up as Ferocious Lane Draws Closer to Hawaii

Bob Henson <https://www.wunderground.com/cat6/author/bob.henson>  =C2=B7 =
 August 21, 2018, 2:53 PM EDT


Above: Visible satellite image of Hurricane Lane at 1800Z (8 am HST and =
2 pm EDT) Tuesday, August 21, 2018. Image credit: RAMMB/CSU/CIRA =
<http://rammb.cira.colostate.edu/ramsdis/online/tropical.asp>.
Hurricane watches are in place for several Hawaiian islands as Hurricane =
Lane=E2=80=94a top-end Category 4 storm on Tuesday morning, with top =
sustained winds of 155 mph =
<http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.27A.201=
808211757>=E2=80=94heads toward a potentially devastating encounter with =
the 50th State. A hurricane watch issued at 11 am EDT Tuesday =
<http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.027.201=
808211443> (5 am HDT) by the NOAA/NWS Central Pacific Hurricane Center =
<http://www.prh.noaa.gov/cphc/tcpages/?storm=3DLane> includes Hawaii and =
Maui Counties, which encompasses the Big Island, Maui, Lanai, Molokai, =
and Kahoolawe. Additional watches and warnings may be required later =
today and as the week unfolds.

It's uncommon for a hurricane to draw close to the Hawaiian Islands, and =
even more rare for one to pose a direct landfall threat, much less a =
hurricane this strong. Only two hurricanes on record have struck the =
islands directly, both of them in Kauai: Category 1 Dot =
<https://en.wikipedia.org/wiki/Hurricane_Dot_(1959)> in 1959, and =
catastrophic Category 4 Iniki =
<https://en.wikipedia.org/wiki/Hurricane_Iniki> in 1992.

Lane was still far from the islands on Tuesday morning=E2=80=94about 600 =
miles southeast of Honolulu, moving west at 12 mph. However, computer =
models have grown more insistent that Lane will turn sharply northward =
later this week, then carry out a broad counterclockwise loop late in =
the week that could involve a direct landfall on one or more of the =
islands. Such a track would be unprecedented in modern Hawaiian history. =
Even if Lane avoids a landfall, an arcing track just left of the islands =
could place many parts of the state on the dangerous right-hand side of =
the hurricane. The seriousness of the worst-case possibilities with =
Lane, and the rarity of the situation, call for an especially high level =
of preparation and vigilance among all Hawaiians.

Hurricane Hunters verify Lane's power

We=E2=80=99re fortunate that NOAA and the U.S. Air Force have been able =
to carry out dropsonde missions to keep tabs on Lane. In many other =
seasons, these aircraft might have been occupied with tropical cyclone =
threats in the Atlantic. Reconnaissance flights since Sunday have =
gathered invaluable observations of Lane, confirming its strength and =
providing data for computer forecast models to ingest. This is the first =
time that a NOAA P-3 has been deployed specifically to sample a =
hurricane threatening Hawaii. The P-3 underwent a rough flight =
<http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCDCP2.EP142018.027.201=
808211457> on Monday evening, with strong turbulence reported; the =
plane=E2=80=99s Tuesday morning flight was cancelled <https://Sorry =
about that! Will fix.  =
https://twitter.com/HRD_AOML_NOAA/status/1031917324583030788> for a =
maintenance check, but the Tuesday afternoon flight was still on. =
<http://twitter.com/HRD_AOML_NOAA/status/1031917324583030788https:/twitter=
.com/HRD_AOML_NOAA/status/1031917324583030788>
Lane became a major hurricane on Friday night, August 17, and has =
oscillated between Category 3 and 4 strength ever since. It appears that =
Lane completed an eyewall replacement cycle on Monday, after which its =
top sustained winds ramped up to 150 mph=E2=80=94not far from Category 5 =
strength=E2=80=94as of 5 am EDT Tuesday =
<http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.027.201=
808211443>.

Incredibly, reconnaissance data on Tuesday morning indicate that Lane =
may have strengthened even further, with an estimated central surface =
pressure down to 940 mb and extremely strong winds at flight levels and =
at the surface.


Satellite imagery shows that Lane=E2=80=99s envelope of showers and =
thunderstorms (convection) has gradually expanded since Monday. The =
hurricane continued to look very healthy on Tuesday morning HST, with a =
crisp, well-defined eye surrounded by intense convection, although there =
has been some recurrent erosion of the strongest convection on Lane=E2=80=99=
s west side.


Figure 1. Infrared image of Hurricane Lane at 1800Z (8 am HST and 2 PM =
EDT) Tuesday, August 21, 2018. Image credit: RAMMB/CSU/CIRA =
<http://rammb.cira.colostate.edu/products/tc_realtime/storm.asp?storm_iden=
tifier=3DEP142018>.
Lane is passing over quite warm water=E2=80=94around 28=C2=B0C (82=C2=B0F)=
, which is 0.5=C2=B0C above average for this time of year=E2=80=94and =
sea surface temperatures will remain in the 27-28=C2=B0C range along =
Lane=E2=80=99s path throughout the week. Vertical wind shear is light, =
less than 10 knots, and that should continue through at least Thursday. =
The mid-level atmosphere surrounding Lane will become increasingly moist =
over the next couple of days, with relative humidity rising from around =
55% to 60-65%. All of these factors suggest that Lane will be able to =
hang tough as a major Category 3 or stronger hurricane through at least =
Thursday. At that point, Lane will likely be about 200 miles south of =
the Big Island, heading north or north-northwest.

Track uncertanties loom large with Lane

The question marks become far more numerous and crucial from Thursday =
through Saturday. Forecast models now agree that Lane will be heading =
generally northward from Thursday into Friday before taking a sharp left =
turn on Friday and then heading generally westward. One critical =
question is how such an unusual track (if it verifies) would overlap =
with the island chain. Lacking few precedents, we must rely on computer =
model guidance.

The 06Z Tuesday run of the HWRF model, one of our more reliable track =
models, suggested that Lane could make landfall on the Big Island as a =
Category 2 hurricane and pass over or near Maui as a Category 1 =
hurricane or tropical storm, while the 12Z Tuesday run shows Lane =
staying just west of the Big Island before making a landfall on Maui. =
The GFS model shows Lane scraping the west coast of the Big Island but =
turning west just before reaching Maui. (We can disregard the much lower =
intensities shown in the GFS, since the model was not initialized with =
Lane=E2=80=99s full strength as a starting point.) Recent runs of the =
European model portrayed a longer but more northwestward vs. northward =
turn, keeping Lane well west of the Big Island and resulting in a =
landfall on Oahu in the 0Z Tuesday run and a track just south of Oahu =
and very near Kauai in the 12Z Tuesday run.

Each of these scenarios is quite concerning, but since they are so =
divergent, it is too soon to predict with precision whether or not Lane =
will pass directly over one or more Hawaiian islands. If such an =
encounter did occur, it would be most likely around Thursday for the Big =
Island and Maui and around Friday for Oahu.


If Lane were to pass over or very near the Big Island, damaging winds =
could be expected in many areas, but the higher terrain of Mauna Loa and =
Mauna Kea would weaken the hurricane rapidly. On the other hand, if Lane =
stays far enough offshore, there would remain some potential for Lane to =
bring hurricane-force winds to one or more islands from Maui northward. =
The other factor that could weaken Lane is wind shear, which is =
predicted to increase rapidly by Friday, as predicted by the 12Z Tuesday =
run of the SHIPS model =
<http://ftp.nhc.noaa.gov/atcf/stext/18082112EP1418_ships.txt>. Even if =
Lane misses the Big Island, this wind shear will likely chip away at =
Lane=E2=80=99s strength. A caveat: it is possible that the increasing =
winds at the jet-stream level will also provide an outflow jet for Lane, =
which could help prolong its strength for a time.

Extreme rainfall, floods, and landslides possible with Lane

One of the biggest threats with Lane is the potential for massive =
rainfall amounts and very serious flooding and mudslides. Wherever =
Lane=E2=80=99s high winds happen to end up blowing against the steep =
terrain of Hawaii, rich moisture associated with the storm will be =
squeezed out by the upslope-flow process. CPHC is warning =
<http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.027.201=
808211443> that 10-15=E2=80=9D rains are possible throughout the island, =
with local amounts as high as 20=E2=80=9D. Far greater peak amounts are =
possible on the most favored windward slopes, depending on Lane=E2=80=99s =
track (see Figure 2 below), although rain gauges may not happen to be in =
the right places to capture those extreme amounts.


Figure 2. This rainfall forecast for Lane, based on a single model run =
(the 06Z Tuesday run of the HWRF model), predicts peak rainfall totals =
exceeding 32=E2=80=9D on the southeast slopes of the Big Island and 16 - =
24" on Maui, peaking from Thursday, August 23, 2018, into Thursday =
night. Image credit: NOAA/NWS/EMC =
<http://www.emc.ncep.noaa.gov/gc_wmb/vxt/HWRF/index.php>.
Rainfall on the east slopes of the Big Island and Maui will not =
necessarily depend on whether or not Lane makes landfall. In fact, a =
track just west of the islands could allow Lane to maintain its strength =
and produce intense upslope and heavier rains over a longer period.

We can expect enormous local variations in rainfall amounts due to the =
topography of Hawaii and the complex interactions with Lane. While the =
highest totals may not fall on populated areas, they could still produce =
massive and rapid rises in rivers and creeks, with the very real =
possibility of landslides and road problems. For example, the road to =
Hana on Maui is at high risk of washouts in very heavy rain. An extreme =
rainfall threat could eventually extend north of Maui, depending on the =
ultimate track of Lane.


Figure 3. The probability of experiencing tropical-storm-force winds =
(sustained at 39 mph or more) at some point between Tuesday, August 21, =
2018, and early Sunday, August 26, based on the current official =
forecast track. Image credit: NOAA/NWS/CPHC =
<http://www.prh.noaa.gov/cphc/tcpages/?product=3Dwind_probs_64_F120&stormi=
d=3DEP142018>.
Lane could produce widespread tropical-storm-force winds

Lane=E2=80=99s impacts will reach far beyond its immediate core. As of =
Tuesday morning, tropical-storm-force winds (sustained at 39 mph or =
more) extended up to 140 miles from Lane=E2=80=99s center. Rick Knabb =
(Weather Channel) pointed out =
<https://twitter.com/DrRickKnabb/status/1031970624426659840>,  =E2=80=9CIt=
=E2=80=99s been a very long time - and probably not ever since the =
NHC/CPHC wind speed probability products were introduced more than a =
decade ago - that essentially every location in the state of Hawaii has =
a greater than 50/50 chance of winds of tropical storm force.=E2=80=9D =
(See Figure 3 above). Such winds can be enough to bring down trees and =
power lines, especially after soils are saturated by heavy rain. The =
highest wind odds are along the southwest coast of the Big Island, where =
hurricane-force winds can be expected if Lane passes nearby or just to =
the west.

Widespread flight cancellations can be expected throughout Hawaii as =
Lane approaches, especially from Wednesday through Friday.

The bottom line: Lane poses a threat to Hawaii that is unique in the =
modern era of hurricane prediction and monitoring. There is increasing =
confidence that Lane will pass close enough to the islands to produce =
widespread damaging tropical-storm force winds and torrential rains. =
Much greater impacts are possible if and when Lane makes landfall, which =
is possible on the Big Island and/or Maui as soon as Thursday. It is =
vital that residents begin their preparations now and pay close =
attention to updates from the Central Pacific Hurricane Center and local =
authorities.

Dr. Jeff Masters contributed to this post.

Bob Henson

WU meteorologist Bob Henson, co-editor of Category 6, is the author of =
"Meteorology Today" and "The Thinking Person's Guide to Climate Change." =
Before joining WU, he was a longtime writer and editor at the University =
Corporation for Atmospheric Research in Boulder, CO.

bob.henson@weather.com <mailto:bob.henson@weather.com>
@bhensonweather <https://twitter.com/bhensonweather>

--Apple-Mail=_48DC89C1-5387-479B-AB4E-64F3459AAF7F
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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><div class=3D"">Friends: &nbsp;Informed commentary from the =
Weather Underground - living with uncertainty</div><div class=3D""><br =
class=3D""></div><div class=3D""><br class=3D""></div><div class=3D""><div=
 class=3D"region-content-top"><top-content class=3D""><div class=3D"row">
  <div class=3D"columns">

    <sharing class=3D""><div id=3D"sharing-icons-browser" =
universalpassthrough=3D"" class=3D""></div>
</sharing>

    <section-title class=3D""><h2 class=3D"is-parent has-subnav">
  <span class=3D"section-title">&nbsp; &nbsp;&nbsp;</span>Hurricane =
Watches Are Up as Ferocious Lane Draws Closer to =
Hawaii</h2></section-title></div></div></top-content></div><div =
_ngcontent-c0=3D"" class=3D"row"><div _ngcontent-c0=3D"" class=3D"small-12=
 large-8 columns"><div =
class=3D"region-content-body"><cat-six-article-detail _nghost-c2=3D"" =
class=3D""><p _ngcontent-c2=3D"" class=3D"">
  <span _ngcontent-c2=3D"" class=3D"article-author">
    <em _ngcontent-c2=3D"" class=3D"">
      <a _ngcontent-c2=3D"" class=3D"article-author-link" =
href=3D"https://www.wunderground.com/cat6/author/bob.henson">Bob =
Henson</a>
    </em>
    &nbsp;=C2=B7&nbsp;
  </span>
  <span _ngcontent-c2=3D"" class=3D"article-created-date">August 21, =
2018, 2:53 PM EDT</span>
</p>



<img _ngcontent-c2=3D"" class=3D"article-img" =
src=3D"https://s.w-x.co/wu/viz-lane-1800Z-8.21.18-835px.jpg">

<div _ngcontent-c2=3D"" class=3D"cat-six-article-body"><table =
style=3D"width: 770px;" cellspacing=3D"1" cellpadding=3D"1" border=3D"1" =
class=3D""><tbody class=3D""><tr class=3D""></tr><tr class=3D""><td =
class=3D""><strong class=3D"">Above: </strong>Visible satellite image of =
Hurricane Lane at 1800Z (8 am HST and 2 pm EDT) Tuesday, August 21, =
2018. Image credit: <a =
href=3D"http://rammb.cira.colostate.edu/ramsdis/online/tropical.asp" =
class=3D"">RAMMB/CSU/CIRA</a>.</td></tr></tbody></table><p =
class=3D"">Hurricane
 watches are in place for several Hawaiian islands as Hurricane Lane=E2=80=
=94a=20
top-end Category 4 storm on Tuesday morning, with <a =
href=3D"http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.=
27A.201808211757" class=3D"">top sustained winds of 155 mph</a>=E2=80=94he=
ads toward a potentially devastating encounter with the 50th State. A =
hurricane watch <a =
href=3D"http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.=
027.201808211443" class=3D"">issued at 11 am EDT Tuesday</a> (5 am HDT) =
by the NOAA/NWS <a =
href=3D"http://www.prh.noaa.gov/cphc/tcpages/?storm=3DLane" =
class=3D"">Central Pacific Hurricane Center</a>
 includes Hawaii and Maui Counties, which encompasses the Big Island,=20
Maui, Lanai, Molokai, and Kahoolawe. Additional watches and warnings may
 be required later today and as the week unfolds.</p><p class=3D"">It's =
uncommon=20
for a hurricane to draw close to the Hawaiian Islands, and even more=20
rare for one to pose a direct landfall threat, much less a hurricane=20
this strong. Only two hurricanes on record have struck the islands=20
directly, both of them in Kauai: Category 1 <a =
href=3D"https://en.wikipedia.org/wiki/Hurricane_Dot_(1959)" =
class=3D"">Dot</a> in 1959, and catastrophic Category 4 <a =
href=3D"https://en.wikipedia.org/wiki/Hurricane_Iniki" =
class=3D"">Iniki</a> in 1992.</p><p class=3D"">Lane
 was still far from the islands on Tuesday morning=E2=80=94about 600 =
miles=20
southeast of Honolulu, moving west at 12 mph. However, computer models=20=

have grown more insistent that Lane will turn sharply northward later=20
this week, then carry out a broad counterclockwise loop late in the week
 that could involve a direct landfall on one or more of the islands.=20
Such a track would be unprecedented in modern Hawaiian history. Even if=20=

Lane avoids a landfall, an arcing track just left of the islands could=20=

place many parts of the state on the dangerous right-hand side of the=20
hurricane. <strong class=3D"">The seriousness of the worst-case =
possibilities with=20
Lane, and the rarity of the situation, call for an especially high level
 of preparation and vigilance among all Hawaiians.</strong></p><h2 =
class=3D""><strong class=3D"">Hurricane Hunters verify Lane's =
power</strong></h2><p class=3D"">We=E2=80=99re
 fortunate that NOAA and the U.S. Air Force have been able to carry out=20=

dropsonde missions to keep tabs on Lane. In many other seasons, these=20
aircraft might have been occupied with tropical cyclone threats in the=20=

Atlantic. Reconnaissance flights since Sunday have gathered invaluable=20=

observations of Lane, confirming its strength and providing data for=20
computer forecast models to ingest. This is the first time that a NOAA=20=

P-3 has been deployed specifically to sample a hurricane threatening=20
Hawaii. The P-3 underwent a <a =
href=3D"http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCDCP2.EP142018.=
027.201808211457" class=3D"">rough flight</a> on Monday evening, with =
strong turbulence reported; the plane=E2=80=99s Tuesday morning flight =
<a href=3D"https://Sorry about that! Will fix.  =
https://twitter.com/HRD_AOML_NOAA/status/1031917324583030788" =
class=3D"">was cancelled</a> for a maintenance check, but the Tuesday =
afternoon flight was <a =
href=3D"http://twitter.com/HRD_AOML_NOAA/status/1031917324583030788https:/=
twitter.com/HRD_AOML_NOAA/status/1031917324583030788" class=3D"">still =
on.</a></p><p class=3D"">Lane
 became a major hurricane on Friday night, August 17, and has oscillated
 between Category 3 and 4 strength ever since. It appears that Lane=20
completed an eyewall replacement cycle on Monday, after which its top=20
sustained winds ramped up to 150 mph=E2=80=94not far from Category 5 =
strength=E2=80=94<a =
href=3D"http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.=
027.201808211443" class=3D"">as of 5 am EDT Tuesday</a>.</p><p =
class=3D"">Incredibly,
 reconnaissance data on Tuesday morning indicate that Lane may have=20
strengthened even further, with an estimated central surface pressure=20
down to 940 mb and extremely strong winds at flight levels and at the=20
surface.</p><br class=3D""><p class=3D"">Satellite
 imagery shows that Lane=E2=80=99s envelope of showers and thunderstorms=20=

(convection) has gradually expanded since Monday. The hurricane=20
continued to look very healthy on Tuesday morning HST, with a crisp,=20
well-defined eye surrounded by intense convection, although there has=20
been some recurrent erosion of the strongest convection on Lane=E2=80=99s =
west=20
side.</p><table style=3D"width: 837px;" cellspacing=3D"1" =
cellpadding=3D"1" border=3D"0" class=3D""><tbody class=3D""><tr =
class=3D""><td class=3D""><img alt=3D"Infrared image of Hurricane Lane =
at 1800Z (8 am HST and 2 PM EDT) Tuesday, August 21, 2018" =
title=3D"Infrared image of Hurricane Lane at 1800Z (8 am HST and 2 PM =
EDT) Tuesday, August 21, 2018" class=3D"file-default media-element" =
data-delta=3D"3" src=3D"https://s.w-x.co/wu/ir-lane-1800Z-8.21.18.jpeg" =
width=3D"835" height=3D"508"></td></tr><tr class=3D""><td =
class=3D""><strong class=3D"">Figure 1.</strong> Infrared image of =
Hurricane Lane at 1800Z (8 am HST and 2 PM EDT) Tuesday, August 21, =
2018. Image credit: <a =
href=3D"http://rammb.cira.colostate.edu/products/tc_realtime/storm.asp?sto=
rm_identifier=3DEP142018" =
class=3D"">RAMMB/CSU/CIRA</a>.</td></tr></tbody></table><p class=3D"">Lane=

 is passing over quite warm water=E2=80=94around 28=C2=B0C (82=C2=B0F), =
which is 0.5=C2=B0C=20
above average for this time of year=E2=80=94and sea surface temperatures =
will=20
remain in the 27-28=C2=B0C range along Lane=E2=80=99s path throughout =
the week.=20
Vertical wind shear is light, less than 10 knots, and that should=20
continue through at least Thursday. The mid-level atmosphere surrounding
 Lane will become increasingly moist over the next couple of days, with=20=

relative humidity rising from around 55% to 60-65%. All of these factors
 suggest that Lane will be able to hang tough as a major Category 3 or=20=

stronger hurricane through at least Thursday. At that point, Lane will=20=

likely be about 200 miles south of the Big Island, heading north or=20
north-northwest.</p><h2 class=3D""><strong class=3D"">Track uncertanties =
loom large with Lane</strong></h2><p class=3D"">The
 question marks become far more numerous and crucial from Thursday=20
through Saturday. Forecast models now agree that Lane will be heading=20
generally northward from Thursday into Friday before taking a sharp left
 turn on Friday and then heading generally westward. One critical=20
question is how such an unusual track (if it verifies) would overlap=20
with the island chain. Lacking few precedents, we must rely on computer=20=

model guidance.</p><p class=3D"">The 06Z Tuesday run of the HWRF model, =
one of our=20
more reliable track models, suggested that Lane could make landfall on=20=

the Big Island as a Category 2 hurricane and pass over or near Maui as a
 Category 1 hurricane or tropical storm, while the 12Z Tuesday run shows
 Lane staying just west of the Big Island before making a landfall on=20
Maui. The GFS model shows Lane scraping the west coast of the Big Island
 but turning west just before reaching Maui. (We can disregard the much=20=

lower intensities shown in the GFS, since the model was not initialized=20=

with Lane=E2=80=99s full strength as a starting point.) Recent runs of =
the=20
European model portrayed a longer but more northwestward vs. northward=20=

turn, keeping Lane well west of the Big Island and resulting in a=20
landfall on Oahu in the 0Z Tuesday run and a track just south of Oahu=20
and very near Kauai in the 12Z Tuesday run.</p><p class=3D"">Each of =
these scenarios is quite concerning, but since they are so divergent, =
<strong class=3D"">it is too soon to predict with precision whether or =
not Lane will pass directly over one or more Hawaiian islands</strong>.
 If such an encounter did occur, it would be most likely around Thursday
 for the Big Island and Maui and around Friday for Oahu.</p><br =
class=3D""><p class=3D"">If
 Lane were to pass over or very near the Big Island, damaging winds=20
could be expected in many areas, but the higher terrain of Mauna Loa and
 Mauna Kea would weaken the hurricane rapidly. On the other hand, if=20
Lane stays far enough offshore, there would remain some potential for=20
Lane to bring hurricane-force winds to one or more islands from Maui=20
northward. The other factor that could weaken Lane is wind shear, which=20=

is predicted to increase rapidly by Friday, as predicted by the <a =
href=3D"http://ftp.nhc.noaa.gov/atcf/stext/18082112EP1418_ships.txt" =
class=3D"">12Z Tuesday run of the SHIPS model</a>.
 Even if Lane misses the Big Island, this wind shear will likely chip=20
away at Lane=E2=80=99s strength. A caveat: it is possible that the =
increasing=20
winds at the jet-stream level will also provide an outflow jet for Lane,
 which could help prolong its strength for a time.</p><h2 =
class=3D""><strong class=3D"">Extreme rainfall, floods, and landslides =
possible with Lane</strong></h2><p class=3D"">One
 of the biggest threats with Lane is the potential for massive rainfall=20=

amounts and very serious flooding and mudslides. Wherever Lane=E2=80=99s =
high=20
winds happen to end up blowing against the steep terrain of Hawaii, rich
 moisture associated with the storm will be squeezed out by the=20
upslope-flow process. CPHC is <a =
href=3D"http://www.prh.noaa.gov/cphc/tcpages/archive/2018/TCPCP2.EP142018.=
027.201808211443" class=3D"">warning</a>
 that 10-15=E2=80=9D rains are possible throughout the island, with =
local=20
amounts as high as 20=E2=80=9D. Far greater peak amounts are possible on =
the=20
most favored windward slopes, depending on Lane=E2=80=99s track (see =
Figure 2=20
below), although rain gauges may not happen to be in the right places to
 capture those extreme amounts.</p><table style=3D"width: 837px;" =
cellspacing=3D"1" cellpadding=3D"1" border=3D"0" class=3D""><tbody =
class=3D""><tr class=3D""><td class=3D""><img alt=3D"This rainfall =
forecast for Lane, based on a single model run (the 06Z Tuesday run of =
the HWRF model), predicts peak rainfall totals exceeding 32=E2=80=9D on =
the southeast slopes of the Big Island and 16 - 24&quot; on Maui, =
peaking from Thursday, August 23, 2018, into " title=3D"This rainfall =
forecast for Lane, based on a single model run (the 06Z Tuesday run of =
the HWRF model), predicts peak rainfall totals exceeding 32=E2=80=9D on =
the southeast slopes of the Big Island and 16 - 24&quot; on Maui, =
peaking from Thursday, August 23, 2018, into " class=3D"file-default =
media-element" data-delta=3D"2" =
src=3D"https://s.w-x.co/wu/hwrf-rainfall-lane-06Z-8.21.18.png" =
width=3D"835" height=3D"626"></td></tr><tr class=3D""><td =
class=3D""><strong class=3D"">Figure 2.</strong>
 This rainfall forecast for Lane, based on a single model run (the 06Z=20=

Tuesday run of the HWRF model), predicts peak rainfall totals exceeding=20=

32=E2=80=9D on the southeast slopes of the Big Island and 16 - 24" on =
Maui,=20
peaking from Thursday, August 23, 2018, into Thursday night. Image=20
credit: <a href=3D"http://www.emc.ncep.noaa.gov/gc_wmb/vxt/HWRF/index.php"=
 class=3D"">NOAA/NWS/EMC</a>.</td></tr></tbody></table><p =
class=3D"">Rainfall
 on the east slopes of the Big Island and Maui will not necessarily=20
depend on whether or not Lane makes landfall. In fact, a track just west
 of the islands could allow Lane to maintain its strength and produce=20
intense upslope and heavier rains over a longer period.</p><p =
class=3D"">We can=20
expect enormous local variations in rainfall amounts due to the=20
topography of Hawaii and the complex interactions with Lane. While the=20=

highest totals may not fall on populated areas, they could still produce
 massive and rapid rises in rivers and creeks, with the very real=20
possibility of landslides and road problems. For example, the road to=20
Hana on Maui is at high risk of washouts in very heavy rain. An extreme=20=

rainfall threat could eventually extend north of Maui, depending on the=20=

ultimate track of Lane.</p><table style=3D"width: 837px;" =
cellspacing=3D"1" cellpadding=3D"1" border=3D"0" class=3D""><tbody =
class=3D""><tr class=3D""><td class=3D""><img alt=3D" The probability of =
experiencing tropical-storm-force winds (sustained at 39 mph or more) at =
some point between Tuesday, August 21, 2018, and early Sunday, August =
26, based on the current official forecast track." title=3D" The =
probability of experiencing tropical-storm-force winds (sustained at 39 =
mph or more) at some point between Tuesday, August 21, 2018, and early =
Sunday, August 26, based on the current official forecast track." =
class=3D"file-default media-element" data-delta=3D"1" =
src=3D"https://s.w-x.co/wu/ts-force-wind-probs-12Z-8.21.18.jpeg" =
width=3D"835" height=3D"678"></td></tr><tr class=3D""><td =
class=3D""><strong class=3D"">Figure 3.</strong>
 The probability of experiencing tropical-storm-force winds (sustained=20=

at 39 mph or more) at some point between Tuesday, August 21, 2018, and=20=

early Sunday, August 26, based on the current official forecast track.=20=

Image credit: <a =
href=3D"http://www.prh.noaa.gov/cphc/tcpages/?product=3Dwind_probs_64_F120=
&amp;stormid=3DEP142018" =
class=3D"">NOAA/NWS/CPHC</a>.</td></tr></tbody></table><h2 =
class=3D""><strong class=3D"">Lane could produce widespread =
tropical-storm-force winds</strong></h2><p class=3D"">Lane=E2=80=99s
 impacts will reach far beyond its immediate core. As of Tuesday=20
morning, tropical-storm-force winds (sustained at 39 mph or more)=20
extended up to 140 miles from Lane=E2=80=99s center. Rick Knabb (Weather=20=

Channel) <a =
href=3D"https://twitter.com/DrRickKnabb/status/1031970624426659840" =
class=3D"">pointed out</a>,
 =E2=80=9CIt=E2=80=99s been a very long time - and probably not ever =
since the NHC/CPHC=20
wind speed probability products were introduced more than a decade ago -
 that essentially every location in the state of Hawaii has a greater=20
than 50/50 chance of winds of tropical storm force.=E2=80=9D (See Figure =
3=20
above). Such winds can be enough to bring down trees and power lines,=20
especially after soils are saturated by heavy rain. The highest wind=20
odds are along the southwest coast of the Big Island, where=20
hurricane-force winds can be expected if Lane passes nearby or just to=20=

the west.</p><p class=3D"">Widespread flight cancellations can be =
expected throughout Hawaii as Lane approaches, especially from Wednesday =
through Friday.</p><p class=3D""><strong class=3D"">The bottom line: =
</strong>Lane
 poses a threat to Hawaii that is unique in the modern era of hurricane=20=

prediction and monitoring. There is increasing confidence that Lane will
 pass close enough to the islands to produce widespread damaging=20
tropical-storm force winds and torrential rains. Much greater impacts=20
are possible if and when Lane makes landfall, which is possible on the=20=

Big Island and/or Maui as soon as Thursday. It is vital that residents=20=

begin their preparations now and pay close attention to updates from the
 Central Pacific Hurricane Center and local authorities.</p><p =
class=3D""><em class=3D"">Dr. Jeff Masters contributed to this =
post.</em></p></div><cat-six-about-author _ngcontent-c2=3D"" =
_nghost-c9=3D"" class=3D""><div _ngcontent-c9=3D"" =
class=3D"cat-six-about-author"><div _ngcontent-c9=3D"" class=3D"row =
collapse cat-six-about-author"><div _ngcontent-c9=3D"" class=3D"columns =
medium-4">
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    <div _ngcontent-c9=3D"" class=3D"columns medium-8">
      <div _ngcontent-c9=3D"" class=3D"author-info">
        <h4 _ngcontent-c9=3D"" class=3D"">Bob Henson</h4><p =
_ngcontent-c9=3D"" class=3D"">WU meteorologist Bob Henson, co-editor of=20=

Category 6, is the author of "Meteorology Today" and "The Thinking=20
Person's Guide to Climate Change." Before joining WU, he was a longtime=20=

writer and editor at the University Corporation for Atmospheric Research
 in Boulder, CO.</p><p _ngcontent-c9=3D"" class=3D"author-contact">
          <a _ngcontent-c9=3D"" href=3D"mailto:bob.henson@weather.com" =
class=3D"">
            <i _ngcontent-c9=3D"" =
class=3D"fi-mail"></i>bob.henson@weather.com
          </a>
        </p><p _ngcontent-c9=3D"" class=3D"author-contact">
          <a _ngcontent-c9=3D"" target=3D"_blank" =
href=3D"https://twitter.com/bhensonweather" class=3D"">
            <i _ngcontent-c9=3D"" =
class=3D"fi-social-twitter"></i>@bhensonweather</a><iframe =
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