Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/09/17
Area Forecast Discussion
National Weather Service Wilmington NC
1102 PM EST Wed Feb 8 2017
.SYNOPSIS...
Clouds and showers will increase in warm air ahead of approaching
cold through tonight. A cold front will move across the area
Thursday morning. High pressure will bring dry and cool weather
Friday. The high will then move off the coast allowing much
warmer temperatures to return during the weekend and early next
week. A cold front will drop south across the area on Monday
bringing slightly lower temperatures for mid week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 1030 PM Wednesday...The band of north to south showers
and isolated tstorms that was in the vicinity of the I-77
corridor earlier...is now approaching the I-95 corridor from
Benson northward. Again, very little development on the
southern end of this band with a few showers popping up in
Robeson County. This will be the case for the remainder of this
evening and into the pre-dawn Thu hours.
Look for the sfc cold front now located nearly along the spine
of the southern Appalachian Mountains and is delineated well
with the line of convection along it. Latest HRRR indicates this
convection will reach the western fringes of the ILM CWA between
07 and 08Z and encompassing nearly the entire ILM CWA by 11Z.
Will have that 50-65 kt low level winds near 850mb early Thu
morning. Any thunderstorm given the high shear low CAPE
scenario, if strong enough, may have the opportunity to pull
down those stronger winds aloft as gusts at the sfc.
Will continue to mention in the HWO and in public zone fcsts of
this possibility. Tonights lows will either occur from any pcpn
occurrence or occur around sunrise Thu, nevertheless, it will
be a mild winter`s night.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...Best lift and moisture will be exiting
off to the east as cold front makes its way off the coast Thurs
morning. A deep NW flow will develop with plenty of drier and
cooler air advecting in. Expect high temps in the morning just
ahead of front with temps falling initially behind front and
then increasing only slightly before falling again. Gusty NW
winds will make it feel even cooler through the aftn. Should
see afternoon temps in the mid 50s most places with plenty of
sunshine.
CAA will continue with temps dropping below freezing overnight
Thurs. Then the high shifts closer overhead allowing winds to
fall off and better radiational cooling by morning under clear
skies. Dewpoint temps will run in the teens early Friday.
Overall, very dry and cool weather through Friday. The center
of high pressure will be almost directly over the tip of Cape
Fear Fri morning. Temps and dewpoints will rebound slowly once
the high shifts off shore late Fri through Sat and a light
return flow develops. A decent radiational cooling night Fri
night will allow temps to drop once again but will fall down
into the 30s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 300 PM Wednesday...Surface high pressure will remain
parked off the southeast CONUS Saturday into Monday. GFS/ECMWF
are in general agreement in this scenario, with above normal
temperatures resulting from return southwesterly flow. Models do
indicate a cold front will approach the forecast area Monday,
but uncertain how much of a push it will have to actually make
it through the CWA, and the ECMWF is quick to establish
southerly flow again by Tuesday. Models diverge by Tuesday into
Wednesday, with the placement of a significant shortwave and
associated surface low which looks to bring the most impressive
chance of rain during the period. The GFS keeps this feature
over the Gulf Coast states through midweek, while the ECMWF
lifts it across the Carolinas on Wednesday. Therefore will carry
a low PoP Monday for what looks to be an unimpressive fropa,
and increase PoPs to chance category Tuesday into Wednesday to
account for uncertainty with the midweek system.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
As of 00Z...Fairly dynamic system moving through the region
toward morning. Look for IFR ceilings to develop with strong
southwesterly flow ahead of the cold front that will sweep
through the region after 08Z. Gusty winds will accompany the
front, both pre and post frontal. There should be a small window
for some decent convection. After the front passes, look for
winds to shift to the west northwest, increasing with gusts over
30 kts possible. Ceilings will quickly scatter after 14Z,
although winds are expected to be strong all day.
Extended outlook...Expect VFR as high pressure transitions
overhead. Next potential for precipitation and possible MVFR
looks like Monday with another cold frontal passage.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 1045 PM Wednesday...SCA is in effect for all waters
commencing at 300 AM Thursday. Current conditions are just shy
of SCA thresholds attm. With the sfc pg further tightening late
this evening and overnight, it will not take much for winds
and/or seas to breach SCA thresholds. The best or higher winds
will occur after the CFP Thu daytime morning. Significant seas
will climb to 4 to 7 ft during the pre-dawn Thu hours with short
period wind driven waves the driver for significant seas.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...Small Craft Advisory conditions will
continue through Thursday in strong NW flow behind cold front.
Expect winds 20 to 25 kts with gusts to 30 KT Thursday
afternoon into the evening. Seas 3 to 5 ft to start will
increase up to 6 to 8 ft through Thurs into Thurs night. As
high pressure moves closer overhead by Friday morning, winds
and seas will diminish leaving a lighter northerly flow heading
into Fri. winds will diminish to 10 to 15 kts and seas will be
down to 3 to 5 ft by Fri morning. By late Fri winds will come
around to the S as high pressure shifts farther off shore. this
will bring seas down further to less than 3 ft by Fri aftn.
LONG TERM /SATURDAY THROUGH SUNDAY/...
As of 3 PM Wednesday...Southwest flow will prevail around
surface high off the southeast coast. Pressure gradient appears
to support generally 15 knots of wind through Sunday, then it
strengthens Sunday night, with speeds increasing to 20 knots.
Seas also build to 5-6 feet in the outer waters by late Sunday
night. Wind shift on Monday will be associated with a weak
frontal passage, with widely scattered showers possible.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory from 3 AM Thursday to 6 AM EST Friday for
AMZ250-252-254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...CRM
AVIATION...DL
Area Forecast Discussion
National Weather Service Indianapolis IN
952 PM EST Wed Feb 8 2017
.UPDATE...
The Near Term Section has been updated below.
&&
.SYNOPSIS...
Issued at 202 PM EST Wed Feb 8 2017
A high pressure system will move across Indiana from the west
overnight. By Saturday morning it should be shifting east of our
state. That will start a period when Indiana is going to be affected
by a complex array of weather makers. Warm fronts, cold fronts with
associated low pressure systems, and high pressure regions will all
play a role in Hoosier weather.
&&
.NEAR TERM (Tonight)...
Issued at 952 PM EST Wed Feb 8 2017
Pulled the Winter Weather Advisory as the snow has ended. However,
issued a Special Weather Statement as the roads will ice up
overnight as temperatures drop through the teens. This should result
in very slick roads overnight and for the morning commute.
Previous discussion follows...
Issued at 630 PM EST Wed Feb 8 2017
Radar was showing the heavier snow band was moving east of the city
and into east central Indiana. Radar trends favor current pops.
Based on observations the last few hours, models including the
mesoscale ones were not picking up on the the magnitude of the north
winds. Had to raise winds and include gusts to 25 mph the next few
hours, and mention the potential for gusty winds to reduce the
visibility due to blowing snow, in the Winter Weather Advisory.
Previous discussion follows...
Issued at 202 PM EST Wed Feb 8 2017
The focus is on snow early in the period.
The HRRR and other convection allowing models (CAMs) agree rather
well. Snow will rapidly develop over the CWA during the rest of
the afternoon and evening, then rapidly end by 06Z. POPs from the
Shortblend model capture this adequately.
The current WSW will be extended one tier of counties south. This
is because the latest HRRR has snow starting in those counties
during rush hour, which will make its impact unusually great. The
advisory will also be extended until 11 pm based on latest model
timing.
Radar shows banding in the snow, consistent with predictions of
strong frontogenesis with this system. Given bands are an issue, the
CAMs should handle amounts best. The Forecast Builder/SuperBlend
process is in good agreement with them and was used for
accumulations.
With general model agreement, consensus temperatures were
used.
&&
.SHORT TERM (Thursday through Friday night)...
Issued at 202 PM EST Wed Feb 8 2017
There is good model agreement an intrusion of cold air tomorrow will
be rapidly followed by warm advection. There is also good agreement
there won`t be any precipitaion because of limited moisture,
although sky cover is likely to vary.
Given strong model correspondence, consensus temperatures ought to
work well. Errors should be 3 degrees or less through Friday, and 4
degrees or less Friday night.
&&
.LONG TERM /Saturday through Wednesday/...
Issued at 231 PM EST Wed Feb 8 2017
Broad ridging aloft will provide a return to mild weather across
the region for much of the weekend. Deep upper trough over the
west coast will split with energy being left behind over the Four
Corners region while a more progressive wave associated with the
northern jet stream helps to drive a cold front and surface wave
through the area late weekend. While precip will be possible from
Saturday afternoon through Sunday...expect most widespread precip
potential will exist Saturday night into Sunday as the surface
wave tracks along the boundary through the region. Weak axis of
elevated instability may spread into the southern half of the
forecast area ahead of the front on Sunday and will maintain an
isolated thunder mention as a result. Highs will once again surge
to above normal levels in the 50s to even lower 60s Saturday and
Sunday.
The remainder of the extended will see quiet and seasonable weather
as a split flow regime aloft persists across much of the country.
The trailing upper level energy will transition east through the
first half of the week...gradually moving into the Tennessee
Valley by Wednesday with a surface wave. Bulk of the extended
model guidance is keeping the impacts from this system south of
central Indiana...but the potential for phasing of jet energy with
the northern stream may serve to pull some of the moisture further
north into the area than currently progged. Have a dry forecast
for Wednesday at this time but will certainly need to monitor in
the coming days. Highs will primarily be in the 40s Monday through
Wednesday with lows in the 20s to around 30.
&&
.AVIATION (Discussion for 090300Z IND TAF Update)...
Issued at 915 PM EST Wed Feb 8 2017
The visibility should be VFR the rest of the night, and should see
ceilings improve to VFR by or before 06z.
Previous discussion follows...
Issued at 545 PM EST Wed Feb 8 2017
Good confidence that IFR and worse flying conditions will improve to
MVFR and then VFR at or slightly after 01z at LAF and HUF and at or
slightly after 02z at IND and BMG, as the upper disturbance and snow
move off to the east. Will keep a one hour buffer window following
those time periods with VCSH per radar trends.
North winds will decrease to 10 knots or less and become northwest
after 03z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...MK
SHORT TERM...JK
LONG TERM....Ryan
AVIATION...MK
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
942 PM CST Wed Feb 8 2017
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
The awaited cold front has marched quickly through the bulk of the
forecast area already this evening and will clear down through the
remainder of southeastern MS over the next two hours or so. As
expected, gusty north winds are kicking up behind the front but
speeds generally remain below advisory criteria and the situation is
covered well by graphics and HWO already. We did have some scattered
storms fire up along the front in our northeast third of zones
earlier this evening, but as of now all this activity has cleared to
the east of the region and no more storms are anticipated.
Considering this, the HWO and related graphics were updated to no
longer reflect a limited risk of severe storms. Otherwise,
temperatures received an ever-so-minor tweak downward owing to weight
of freshest short range model consensus. Still, anticipating even
the chilliest northern zones late tonight to still remain above
freezing. /BB/
Prior discussion below:
Tonight through Thursday,
Remaining low clouds from this morning have cleared out. Increased
insolation and mixing along with continued warm advection have made
for a record to near record warm afternoon across NWS Jackson
territory. However, changes are coming as a cold front currently
extending from the ArkLaTex through the Mid South makes a
southeastward push into the forecast area this evening.
Right now, there is no activity ongoing along this front due to a
lack of forcing and relatively little deep layer moisture. However a
shortwave, showing up on afternoon WV imagery as a slight swirl over
the Ozarks, will swing across the Deep South this evening. This,
along with the advancing front, will provide sufficient forcing for
a broken line of convection to develop near the Highway 82 corridor,
moving southeastward through East MS. Forecast soundings indicate
roughly 1000 J/kg of MLCAPE will be available, though the CAPE
profile is somewhat skinny. More impressive deep layer shear on the
order of 60-70 kt will help to overcompensate for this. Thus, some
of these storms could become severe. With development not expected
to occur until the front is over the area, there is some question as
to whether storms will mature to severe levels before exiting the
state. While deep layer shear will be impressive,fortunately low
level SRH will not be favorable for tornadoes. For now, we are
maintaining a limited threat in the HWO for lower-end severe storms,
with hail and damaging winds as the possible threats.
Aside from storm threats, a sharp pressure gradient is anticipated
immediately along the front. Recent HRRR runs have indicated fairly
potent gusts to around 35 kt immediately along the front. This seems
a bit aggressive, however, gusts to 30 kt do seem plausible. This
would not meet wind advisory criteria, however, it could be enough
to cause some minor issues over a large area. Thus, a limited threat
mention for strong non-thunderstorm wind gusts was added to the HWO
and graphics for the evening hours. Though breezy conditions will
persist overnight, the strongest gusts should subside before
midnight.
Behind the front, things will clear out overnight, though northerly
winds will remain gusty at times into the day Thursday. After
teasing 80 degrees today, highs tomorrow only in the upper 40s to
low 60s will be a bit of a shock to the system, though in reality,
these readings will be closer to normal for this time of year than
what we`ve been experiencing recently. /DL/
Thursday night through next Wednesday,
For Thursday night, with strong ridging and somewhat anomalously
strong surface ridge axis moving over with clear skies and light
winds, we should be able to radiate well tomorrow night into the
lower 30s. Some areas in northeast Mississippi could fall below
freezing as well. With moisture low (PW`s in the quarter to half inch
range), we will remain quiet and dry through the late week.
As the surface ridge builds east, expect boundary layer temperatures
to moderate back on the upswing similar to what we previously went
through, which will bring back warm temperatures Friday through the
weekend. In addition, as the surface ridge builds to the east over
the Appalachians off the east coast, expect return flow to bring back
in moisture with PW`s climbing back near the 1 inch range in the west
and increasing isentropic ascent from a weak shortwave moving through
our northwest areas. This will bring some light rain chances back in
on Saturday afternoon in the Delta before lessening in the evening.
Expect a more active pattern for rain and some storms as we move
into the late weekend into early next week. Aloft a strong upper
trough will be moving into the Great Lakes while a deep digging
near cutoff upper low will be moving into the lower Rockies. At the
surface a strong stalled front will be situated through the lower
Mississippi Valley with a strong surface low up in the southern
Canada into the mid-Atlantic states. A strong ridge will be moving
in the wake of the front into the central Plains.
For our area, expect the cold front to bring cooler temperatures
back closer to normals as we move into the work week with increasing
rain chances Sunday afternoon in the Delta and lingering through mid
week. For now, lapse rates are meager through the period and mainly
some potential for thunder and maybe a couple of strong storms in the
Delta exists on Sunday along that boundary. As that cutoff low
becomes more phased out west and propagates east, this will help
spark some type of surface low either somewhere near the coast or
into our area. Due to the temperatures being cooler, moisture on the
increase (PW`s closer to an inch and a quarter or higher) and the
more southern track of the surface low, this will keep our
thunderstorm and inclement weather chances low with this system. As
this trough swings through around mid-week, expect drier and cooler
temperatures in the wake. /DC/
&&
.AVIATION...
00Z TAF discussion:
The biggest impact to aviation through tonight will be associated
with a rapid wind shift as a strong cold front drops southeast
through the region this evening. Winds will shift from southwest to
northwest to north and gusting up to 30 mph as the front passes
through the region. In addition, some storms could accompany this
FROPA, but mainly at GWO/GTR/CBM/NMM/MEI. FROPA will happen in the
next hour or two at GLH/GWO/GTR/CBM and around mid-evening at
HKS/JAN/NMM/MEI, and then late this evening at PIB/HBG. A relatively
brief period of MVFR ceilings may occur along and just behind the
FROPA, but otherwise anticipate mainly VFR conditions through the
next 24 hours. Winds tomorrow will slacken some, remaining from the
north with occasional gusts to upwards of 15 mph. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 41 56 35 69 / 2 0 0 0
Meridian 40 56 31 65 / 7 0 0 0
Vicksburg 40 55 36 70 / 0 0 0 0
Hattiesburg 46 62 35 69 / 6 0 0 0
Natchez 43 58 38 70 / 1 0 0 0
Greenville 36 48 34 65 / 0 0 0 0
Greenwood 35 51 32 68 / 0 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
DL/EC/BB
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
733 PM CST Wed Feb 8 2017
.UPDATE...
Issued at 730 PM CST Wed Feb 8 2017
Temperatures are beginning to tank across the fresh snowcover up
north. KANW fell to 3F this hour. A new forecast is in place using
2/3 of the HRRR and 1/3 of the previous forecast for lows in the
single digits below zero across the KVTN-KANW-KONL region. The
HRRR was the coldest model available.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 329 PM CST Wed Feb 8 2017
Tonight...Main forecast issue for this period are tonight`s low
temperatures. I have adjusted lows a few degrees cooler than models
are outputting as feel models are not taking into account recent
snowfall across north central and the northern Sandhills from last
night. A narrow band of 6 to 10 inches fell in a line from Chambers
extending west northwest to Gordon...elsewhere across north central
and the northern Sandhills 2 to 5 inches fell. With this thick
snowcover feel that lows will hover near zero across the area with
the greatest snow pack. Wind chills will range from minus 1 to minus
15 degrees below zero tonight. Across southwest Nebraska have kept
temperatures in the teens as this area does not have snow covered
ground and felt they would stay slightly warmer.
For Thursday...Temperatures were once again the main focus as a
surface high will be to our east bringing us a more southerly flow
for tomorrow have temperatures reaching the 50s to low 60s across
far southwest Nebraska. However I have lowered temperatures several
degrees below guidance across our northern forecast area where snow
pack exist. With several inches of fresh snow pack in the area
temperatures will struggle to warm so have kept them in the 30s
along the area of greatest snowfall.
.LONG TERM...(Thursday night through Wednesday)
Issued at 329 PM CST Wed Feb 8 2017
The models have strengthened the thermal ridge Friday to near 20C at
h850mb. Guidance across the snow-free south indicates highs in the
70s but frozen ground...high clouds and increasing moisture should
lower the forecast to around 70 if not cooler. The cold
ground...abundance of moisture...precipitable water near 0.70 inches
and dew points in the 30s to around 40 Friday...would suggest cooler
readings like 50s or 60s for highs.
A blend of guidance and bias corrected model data produces highs in
the 40s to near 50 across the snow-covered north Friday. A weak cold
front will drop in Friday afternoon and between this and the
possible high cloudiness...cooler highs are possible in this area
also.
A weak midlevel disturbance will operate on a Pacific cold front
Friday night and Saturday producing rain changing to snow. The NAM
was quicker than the GFS to changeover to snow. Rain and snow
amounts should be light given the better forcing will drop through
the Rockies.
The Pacific cold front knocks h850mb temperatures back to -5C
Sunday. A gradual warming to +5C occurs Monday through Wednesday
supporting highs in the 40s to around 50. The forecast is dry after
Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 515 PM CST Wed Feb 8 2017
VFR is expected all areas overnight through Thursday afternoon.
A midlevel warm front will form across Wrn and Ncntl Neb tonight.
This will produce a mid level deck of clouds...BKN-OVC100-120.
The clouds are expected to move northeastward Thursday morning
with generally clear skies Thursday afternoon.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...CDC
SHORT TERM...Gomez
LONG TERM...CDC
AVIATION...CDC
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
911 PM CST Wed Feb 8 2017
.DISCUSSION...See updated information for land areas below.
&&
.UPDATE...Cold front, draped from eastern Kentucky to the upper
Texas coast this evening, is beginning to make steady southeast
progress. Deep convection, out ahead of this front, is more focused
well to the north and east of the local area where the best upper
level dynamics are moving thru from northwest Georgia, southwest
to near Birmingham. There is isolated convection which is close to
clipping the northern tier of zones. The latest high resolution
HRRR guidance suggests that the overall structure of the southern
most activity will begin to weaken over the next several hours
over the interior. Even so, will maintain a small percentage
chance of seeing a passing shower or storm over the interior. As
far as fog, latest observations indicate that coverage is patchy.
A look at web cams over area bays not showing much problem with
fog as well, so have let dense fog advisory over the coastal
zones and near shore waters expire at 9 PM. Frontal passage and
resultant wind shift of moderate strength during the pre-dawn
hours will bring drier and cooler air to the region. /10
MARINE...A cold front is still on track to near the coast by
midnight and then be just offshore by daybreak Thursday.
Strengthening offshore flow with wind speeds of 20-25 knots
expected in the wake of the frontal passage. Small Craft
Advisories continue for the coastal waters out 60 NM, including
Lower Mobile Bay and the Mississippi Sound. Seas building 4-6
feet near shore and up to 5-8 feet well offshore through early
Thursday morning. /10
The moderate to occasionally strong north flow will become more
northeasterly Thursday night, then begin to weaken slightly and
become more east and southeasterly Friday and Friday night as the
surface high pressure moves well east of the marine area. Onshore
flow should then continue through the weekend. /21
&&
.PREV DISCUSSION... /issued 548 PM CST Wed Feb 8 2017/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...
00Z issuance...Low cigs linger into the evening with bases
generally within IFR ranges. Development of BR reduces vsbys to
IFR ranges as well. Southwest flow gusty at times. Frontal passage
brings wind shift during the pre-dawn hours Thu. /10
PREV DISCUSSION... /issued 403 PM CST Wed Feb 8 2017/
NEAR TERM /Now Through Thursday/...Cold front moves from
northwest to southeast over the area late this evening/overnight,
with a cooler and drier northwesterly flow developing its wake.
Dry weather is expected Thursday. Lows tonight should range from
the mid to upper 40s over interior areas to the lower to mid 50s
near the coast. Highs Thursday should range from the upper 50s to
lower 60s interior to the mid 60s near the coast. /21
SHORT TERM /Thursday night Through Saturday night/...An upper-
level ridge over the western CONUS moves east across the Plains
and eastern CONUS through the short term as the next trough digs
into the southwestern U.S., with the resulting subsidence aloft
helping to keep skies mostly clear over the weekend. At the
surface, high pressure over the eastern CONUS moves off the coast
and settles over the southwestern Atlantic, leading to a shift in
surface flow over the local area to easterly and then southeasterly
Friday into the weekend. Will see a rise in moisture and
temperatures over the weekend as a result.
Thursday night temps will be quite a bit cooler than the remainder
of the short term given the dry and cool northerly flow in the wake
of tonight`s cold front. Expect lows in the low 30`s across the
interior to low 40`s along the coast. Highs on Friday will likewise
be a bit cooler since the return flow will yet to have been
established, with temps only expected to reach the mid 60`s across
the area Friday afternoon. Friday night begins the warming trend as
winds shift to southerly and warm, moist air is transported into the
area. Lows Friday night should range from mid 40`s across the
northeastern portions of the forecast area to mid 50`s across
southwest portions. Highs Saturday then expected to return to above
normal, reaching the mid to upper 70` across the area before
only dipping into the upper 50`s to low 60`s Saturday night. /49
LONG TERM /Sunday Through Wednesday/...The aforementioned trough
digging into the SW US over the weekend sheds a closed-off low over
northern Mexico while its parent shortwave continues to push east
across the Plains and eastern CONUS. As a result, will see a cold
front approach the local area early next week. Model solutions
diverge from there, with the Euro taking the closed low on a faster
and more northerly track across the South Plains and into the
Tennessee Valley, which would keep the local area under warm and
moist southerly flow until the low moves on and the front passes
through early Wednesday morning. Meanwhile, the GFS slows down the
low as it crosses through southern Texas and enters the western
Gulf, leading to the aforementioned cold front stalling farther
south along the coast and the local area seeing cooler northerly
flow into the middle of next week. The GFS then swings the low
across the Gulf and through the area later Wednesday into Thursday.
In either scenario, looking like chance for precip increases Monday
into the middle of next week, with the biggest difference between
the solution being where the front stalls and therefore where the
best instability (and attendant chance for thunder) sets up. Have
leaned more towards the Euro solution for now, keeping the mention
for thunder in Tuesday, though the evolution of the closed low will
need to be monitored over the coming weekend.
As for temperatures, early part of next week has better confidence
in above-normal levels with temps expected to reach low to mid 70`s
Sunday and Monday afternoons. Temps then cool some into midweek,
with highs in the mid 60`s expected. Lows will remain similarly
mild through the early part of next week (low to upper 50`s inland
to the coast, respectively) given the warm and moist return flow
across the area. /49
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk until midnight CST tonight for ALZ265-266.
FL...High Rip Current Risk until midnight CST tonight for FLZ202-204-
206.
MS...None.
GM...Small Craft Advisory until noon CST Thursday for GMZ631-632-650-
655-670-675.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Nashville TN
917 PM CST Wed Feb 8 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
The consequential precipitation which included showers and
thunderstorms has moved off to the east. Upstream, pva and low
cloudiness is still expected to work across the area. Soundings
reveal some high level cloud seeding late tonight. Furthermore,
latest numerical data suggests that snowfall across the plateau
will be the precip type toward 12z. Amounts will be light and the
chances for measurable precip will be on the low side. Across that
plateau area it looks as though freezing levels will drop down to
around 2500 ft msl around 09z. Will go ahead and include a light
rain and snow mix late, the pops will be 20 to 30 percent only.
Sfc temps across the Plateau wont likely get below freezing until
around sunrise. At that time, the precip in the area is likely to
be just snow flurry activity.
&&
.AVIATION...
00Z TAF DISCUSSION.
With current svr tstm watch number 31 in effect spent most time on
dealing with first few hrs of valid aviation forecast period.
However, sfc front has moved S of CKV/BNA, and thus other than
some passing shwrs thru 06Z, no impacts from any convection
anticipated. However, persistence of IFR ceilings though
expected. Latest HRRR model runs showing main line of convection
pushing E of CSV by 02/09Z, and with convection quick moving, will
address any impacts of tstms in TEMPO group. Expect most of the
rainfall to move E of BNA/CKV terminals by 09/06Z, with some
lingering light shwrs across CSV thru 09/09Z. Some potential for a
wintry mix 09/09Z-09/14Z CSV, but iso minimum amounts at best
expected. Finally, building sfc high pressure influences/dry nwly
flow aloft will result in deterioration of IFR/MVFR ceilings
09/14Z-09/17Z. VFR/SKC conditions expected at all terminals
afterwards, as sfc winds predominately nwly 10-15kts with gusts
to around 20kts diminishing.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......21
AVIATION........31
Area Forecast Discussion
National Weather Service Norman OK
937 PM CST Wed Feb 8 2017
.UPDATE...
Updated hourly temperature/dewpoint forecast through 13Z.
&&
.DISCUSSION...
Many locations have cooled quicker than anticipated. Therefore,
opted to trend hourly temperatures lower based on current
observations and a time-lagged ensemble of the last few HRRR runs.
As a result, some locations low temperatures were lowered 1-2F.
Also lowered dewpoints as observed values have been generally
lower than previously forecast.
Otherwise, no significant changes were made to the forecast.
Expect a seasonably cold night with low temperatures ranging from
the upper 10Fs across northern Oklahoma to near 30F across
southern Oklahoma/western north Texas.
Mahale
&&
.PREV DISCUSSION... /issued 545 PM CST Wed Feb 8 2017/
DISCUSSION...
The February 9-10, 2017 00 UTC TAF discussion follows:
AVIATION...
VFR conditions will continue through the TAF period. Gusty
northerly winds are expected to weaken the next 1-2 hours. The
northerly winds will shift to the northeast, to the east, to the
southeast, and finally the south through the overnight/morning
hours. Southerly winds are expected to become gusty by tomorrow
afternoon--especially across western TAF sites.
Mahale
PREV DISCUSSION... /issued 242 PM CST Wed Feb 8 2017/
DISCUSSION...
Cold air has poured into the region following last nights cold
front...keeping todays highs in the 40s and 50s. Winds will shift
back around to the south overnight, allowing a fairly quick return
of moist warm air over the next few days...with temperatures
reaching near or above record values. When you add in fairly gusty
winds, fire weather concerns will be elevated over this period,
especially across the warmer and drier western parts of the CWA.
Saturday night another strong cold front is expected to make its
way through the area, bringing temperatures back down to near
normal. As this strong upper level low slowly makes its way across
the region, precipitation chances will increase for early next
week. Low temperatures may allow for some periods of rain/snow
mix at times, though not expecting any appreciable accumulations.
Day
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 25 53 44 73 / 0 0 0 0
Hobart OK 27 56 44 79 / 0 0 0 0
Wichita Falls TX 29 59 46 77 / 0 0 0 0
Gage OK 22 59 44 83 / 0 0 0 0
Ponca City OK 19 48 41 74 / 0 0 0 0
Durant OK 29 55 42 71 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
10/10
Area Forecast Discussion
National Weather Service Mount Holly NJ
926 PM EST Wed Feb 8 2017
.SYNOPSIS...
Low pressure will intensify as it moves from Virgina to the
Delmarva coastline overnight and heads toward New England by
tomorrow night. High pressure will build southeast behind the
departing low pressure system on Friday. However, a warm frontal
boundary will move northeast into the region on the backside of
the high pressure system and stall across the region. A cold
front will then push the warm front and any areas of low
pressure east of the region. Another low pressure system looks
to track from the gulf northeast toward the region by the middle
of next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Low pressure is forecast to develop in Virginia during the
night and it should pass off the middle Delmarva coast toward
daybreak. A mid level trough approaching from the west will
provided favorable conditions for the low to deepen rapidly.
Already a broad area of precipitation has developed to our west. We
expect this precip to move into our region sometime after
midnight. Already in the southern Poconos, temperatures are low
enough that any precip moving in should be all snow. For the
rest of the region however, temperatures have generally been
slower to drop than previously forecast, so adjusted the hourly
temperatures to match. However, even with the adjustments to the
hourly temperatures, timing of the transition of precip type has
not changed much. Having said that however, current road/surface
temps show a very warm ground, and recent runs of the HRRR and
RAP indicate the precip may pull out a bit faster than
previously expected. Thus, lowered snow totals across the region
slightly. Hesitate to drop them too much before we have even
begun to see the effects of dynamic cooling with the low, and
once the heavier snow rates develop, they could be enough to
overcome any warm ground. Regardless of the snow totals, this
still looks to have a major impact for much of the region`s
morning commute as that will be when the heaviest snow is
expected to occur.
A northwest to north wind around 5 to 10 MPH this evening is
expected to veer toward the northeast overnight increasing to 10
to 20 MPH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
The maximum lift with the system is forecast to pass over our
region during Thursday morning`s commute. Precipitation rates
should be at their greatest at that time with snowfall rates up
to around 2 inches per hour. Also, we have kept the mention of
thunder in the southeastern part of our region. The heavy snow
will create very hazardous travel conditions during the morning
commute due to reduced visibility and snow accumulating on
roads.
We made only minor adjustments to the snowfall forecast at this
time. The most noticeable change is an increase in snow totals
for parts of central New Jersey including Monmouth County and
vicinity. Snow may linger a bit longer in that area as the
system pulls away from us, resulting in a bit more accumulation
than previously thought.
It appears as though the back edge of the steady snow will work
its way from west to east across our forecast area between
about 9:00 AM and 1:00 PM. We will keep the ending time on the
Winter Storm Warning and the Winter Weather Advisory as they are
to provide a bit of a cushion.
Maximum temperatures on Thursday are expected to be mostly in
the 30s in our region. Readings should not get above the 20s in
the north.
A gusty northeast to north wind is anticipated to back to the
northwest for the afternoon. Sustained speeds are forecast to
favor the 15 to 20 MPH range with gusts of 25 to 30 MPH. Wind
gusts may approach 35 MPH near the coast but we are thinking
that we should fall just below Blizzard Warning criteria there.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Even though the main storm is tomorrow the extended still looks
active and somewhat wintry.
Thursday night: Behind the rapidly strengthening storm system
winds will still be fairly intense from the north and northwest
due to the pressure gradient with gusts around 20 mph. With the
much colder air coming in to the region wind chills may fall to
around 0 overnight for the central and northern portions of the
region. Another shortwave coupled with the northwest flow and
steep low level lapse rates will still promote the chance for
snow showers in Delmarva and the Southern Poconos/ NW NJ.
Modeling has actually been fairly consistent with setting up a
band of snow showers across Delmarva Thursday evening. With
temperatures in the 20`s along with the favorable snow growth
and instability it will not take much for localized
accumulations around an inch with 20:1 ratios. Given the high
impact event Thursday morning a snow map will not be made for
this event yet. Additional snow showers may work into the
typical areas near the Southern Poconos and northwestern NJ with
the same type of localized accumulations.
Where skies clear low temperatures could really tank but will
be highly dependent on clouds and wind throughout the night.
MET/MAV likely several degrees to warm in many spots particular
yin areas of central NJ and eastern PA that see some clearing.
Lows could fall into the single digits in a few spots with 10`s
elsewhere.
Friday through Saturday:
Continued nw flow, with high pressure over the region, cold and
a break in the action ahead of the next system. Highs will
likely struggle into the 20`s during the day and be cooler than
MET/MAV given the CAA and 925 mb modeled temps near -10C. Highs
will actually be toward midnight.
A warm front will move into the region with a clipper system
traveling west to east along it. Milder air will attempt to
surge into the region by Saturday. However, low level cold and
snow cover will be in place. This typically leads to model
tendencies for not picking up on low level cold. Temperatures
were much slower to rise than modeled over the higher terrain
yesterday as an example. Some light snow is likely to occur near
and north of the clipper track with the highest chances across
northern NJ and the Southern Poconos, another 20:1 type event in
terms of ratios making it easier to get a quick inch in spots.
temperatures should slowly rise into the 30`s and 40`s by late
Saturday.
Saturday night Through Monday: Another low pressure will track
into the Great Lakes along the warm front Sunday and Sunday
night. With high pressure still located further north of our
region, a CAD situation with models underestimating low level
cold is likely to continue. Additonal precipitation will move in
as well. Right now modeling is fairly consistent with the upper
levels being well above freezing with the potential with low
level cold trapped at the surface across the Southern Poconos
and northern New Jersey. As a result, freezing rain would be
possible in spots Sunday morning. The main cold front is
expected to cross the region Sunday night into Monday with more
widespread showers and a quick warm surge ahead of the cold
front. the highest temperatures will likely be during the
evening or overnight hours Sunday night.
Monday night through Tuesday night: Another shot of colder nw
flow behind the front, with a brief break thanks to an area of
high pressure passing to the north. Another round of 20 mph or
higher west-northwest gusts as well. Seasonable with 20`s for
lows and 30`s/40`s for highs in most areas. Stayed close to
ensemble guidance.
Wednesday: Fairly good ensemble agreement of a low pressure
system lifting from the Gulf of Mexico northeast toward our
region. Typical timing and track uncertainties exist for day 7.
Temperatures will be more uncertain depending on the northern
branch of the jet. With the NAO/AO trending negative for the
first time this year, a miller A track could very well occur up
the coast with wintry implications for Wednesday and Thursday of
next week.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
VFR conditions are anticipated through at least 06Z with an
increase in cloud cover. The precipitation is expected to move
in from west to east between 03 and 09Z. For KABE and KRDG, the
precip will likely begin as RASN for a few hours before
changing over to all SN. For the Delaware Valley and Coastal
Plains TAF sites (including KPHL, KPNE, KTTN, KILG, KACY, and
KMIV), the precip is expected to begin as rain before changing
over to a rain, snow, and sleet mix and eventually all snow. The
snow is anticipated to become moderate to heavy at times before
15Z with LIFR and VLIFR conditions expected. The steady snow is
forecast to end gradually from west to east across our TAF
sites between 15Z and 18Z with some improvement (at least to
MVFR) for Thursday afternoon.
Snow may accumulate on runways and taxiways. Amounts should be
around 6 to 10 inches at KRDG, KABE and KTTN. Totals are
forecast to be about 4 to 7 inches around KILG, KPHL and KPNE
with perhaps 2 to 4 inches at KMIV and KACY.
Due to a communications issue, the observation for KACY is not
being transmitted. Thus, AMD NOT SKED was appended to the ACY
TAF, though we will do our best to keep up with changing
conditions at ACY by dialing in to the site.
Outlook...
Thursday night: West-northwest wind gusts 15-20 knots. Mainly
VFR with a few scattered snow showers possible at KACY and KILG
which may briefly lower restrictions.
Friday: VFR, Westerly wind gusts approaching 20 knots.
Friday night: Mainly VFR with lighter winds, lower restrictions
from light snow possible at KABE.
Saturday: VFR.
Saturday night through Sunday night: MVFR or lower restrictions
possible with rain.
Monday: Improving to VFR, another round of west or northwest
wind gusts near 20 knots.
&&
.MARINE...
The Gale Warning remains in effect for Thursday as
strengthening low pressure pass off the middle Delmarva coast
early in the day then moves northeastward and farther out to
sea. The wind direction is forecast to go from northwest and
north early tonight to northeast for late tonight and Thursday
morning. The wind direction should go back to the northwest for
Thursday afternoon.
Wave heights on our ocean waters are anticipated to build to 7
to 11 feet on Thursday.
Outlook...
A gale warning remains in effect for Thursday night with SCA
gusts lingering into Friday. Seas may approach five feet
Saturday and then again Monday.
&&
.TIDES/COASTAL FLOODING...
Strong low pressure is forecast to pass off the middle Delmarva
coast early on Thursday morning before moving out to sea. We
are anticipating a strengthening northeast flow overnight before
the wind goes back to the northwest on Thursday afternoon.
High tide along the oceanfront is from 5:30 to 6:30 AM
Thursday. The duration of the onshore flow leading up to the
high tide should not be long enough to result in anything more
than spotty minor flooding. As a result, a Coastal Flood
Advisory does not appear necessary.
&&
.CLIMATE...
Everyone`s a winner today with all of our climate sites having
record high temperatures today! Only One (Reading) came in with
a record tied. Here is the list of todays highs and the
previous record for today.
Philadelphia PA 66 (63 in 1925)
Allentown PA61 (59 in 1965)
Atlantic City NJ71 (69 in 1965)
Wilmington DE 70 (66 in 1965)
Reading PA 63 (63 in 1965)
Trenton NJ 65 (62 in 1933)
Mt. Pocono PA50 (48 in 2000)
Georgetown DE 73 (69 in 1965)
A winter storm will impact the area late tonight and Thursday
with significant snow for many places. Here are the daily
snowfall records for February 9th.
Philadelphia....6.5 inches in 2010
Allentown.......5.0 inches in 1936
Wilmington......6.0 inches in 1936
Atlantic City...4.1 inches in 1987
&&
.EQUIPMENT...
Due to a communications issue, the Atlantic City Airport
observation is not being sent out. However, the sensors are
still still operating and we were able to dial in to the site to
check the climate data for the afternoon climate.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Winter Storm Warning until 4 PM EST Thursday for PAZ054-055-
060>062-101>106.
Winter Storm Warning from 4 AM to 4 PM EST Thursday for PAZ070-
071.
NJ...Winter Storm Warning until 4 PM EST Thursday for NJZ001-
007>010-012-013-015.
Winter Weather Advisory from 8 AM to 2 PM EST Thursday for
NJZ021>025.
Winter Storm Warning from 4 AM to 4 PM EST Thursday for NJZ014-
016>020-026-027.
DE...Winter Weather Advisory from 8 AM to 2 PM EST Thursday for
DEZ002.
Winter Storm Warning from 4 AM to 4 PM EST Thursday for DEZ001.
MD...Winter Weather Advisory from 8 AM to 2 PM EST Thursday for
MDZ012-015.
Winter Storm Warning from 4 AM to 4 PM EST Thursday for MDZ008.
MARINE...Gale Warning from 6 AM Thursday to 6 AM EST Friday for ANZ430-
431-450>455.
&&
$$
Synopsis...Gaines
Near Term...Iovino/Johnson
Short Term...Iovino
Long Term...Gaines
Aviation...Gaines/Iovino/Johnson
Marine...Gaines/Iovino/Johnson
Tides/Coastal Flooding...
Climate...
Equipment...
Area Forecast Discussion
National Weather Service Portland OR
303 PM PST Wed Feb 8 2017
.SYNOPSIS...A very moist frontal boundary will reach the coast this
evening and then slowly move inland late tonight and Thursday.
Offshore low-level flow will persist through Thursday, which will
maintain cold air in the Columbia Gorge, Hood River Valley and parts
of east Skamania County in SW Washington. Significant ice and snow
can be expected in these areas through Thursday. A secondary trough
swings into the area late Thursday night and Friday morning, which
could result in a second round of high wind along the coast.
Unsettled conditions continue through Saturday. High pressure finally
returns late Saturday and Sunday and will hold through the first part
of next week.
&&
.SHORT TERM...Tonight through Saturday...Water vapor imagery early
this afternoon showed an upper low near 50N 140W slowly retrograding
west. Another low was near 40N 140W. A warm front extended from the
latter low into SW Washington. There is an extended moisture fetch
from the Washington coast to near Hawaii. Blended precipitable water
rates are on the order of 1.2 to 1.5 inches, with up to 2 inches near
Hawaii.
Web cams and spotter reports indicate mainly snow in the Columbia
Gorge east of Multnomah Falls, in the Hood River Valley and
valleys east of the Wind River Valley in SW Washington. Up to 10
inches of snow have fallen near Glenwood in the Trout Lake valley
area of the S Washington Cascades since late last night. There have
been reports of -FZRA a few miles NNW of Carson, near the Wind River
highway. The webcam near Cape Horn, along highway 14 on the
Washington side of the Gorge, also seems to suggest freezing rain.
Also seeing a transition to sleet and freezing rain in portions of
the Hood River Valley. Temperatures as of 21Z remain near freezing as
far west as Corbett in the West Columbia Gorge. Strong isentropic
lift and impressive 700 mb omega are associated with the warm front.
12Z models show increasing SW 850 mb flow later today and tonight,
reaching 60 to 80 kt by 09Z Thu. Although the direction is not
optimum, this will result in very efficient orographic flow into the
Oregon Coast Range, especially for southwest-facing slopes. No change
in forecast storm-total QPF (through Fri morning), with 3-6 inches
for the coast and higher terrain. Interior valleys should see 1-2
inches.
The high wind watch has been upgraded to a high wind warning and will
include the South Washington beaches and headlands. In general,
models do not show a favorable surface gradient until the secondary
trough moves through late Thursday night. Models maintain some east
component, which is not conducive to high wind along the coast. The
19Z HRRR indicates a ribbon of 50-55 kt 80m wind speeds along the
south coast around 06Z Thu, then pushing north overnight. The NAM and
GFS soundings also indicate 65-85 kt SW wind between 3000 and 7000 ft
MSL late tonight. However, the air mass will be quite stable, which
will result in laminar flow. This makes it difficult to obtain any
momentum transfer to the surface.
The cold air in the Gorge, Hood River Valley and areas around Mt.
Adams will be difficult to eliminate. As of 21Z the KTTD-KDLS
gradient was -8.0 mb, pretty close to the 3 hr NAM forecast.
Temperatures will remain below freezing for most of these areas
through at least Thu morning. The cold air will be deep enough to
allow precip to fall as snow in the Central Gorge, Hood River Valley
and valleys of east Skamania County through tonight. These areas will
likely see a transition to more -FZRA late tonight or Thu morning.
The West Gorge (to about Corbett) will see -RA and -FZRA through
tonight, with the highest ice accretion between Multnomah Falls and
the east end of KCZK. This also includes the same coverage on the
Washington side. Eventually, the strong warm advection aloft will
chip away at this cold air. As is often the case, the cold air will
be most stubborn in the Gorge where it is difficult for south wind to
reach the surface. Models are notorious for scouring out the cold air
too soon. Storm-total ice accumulation is expected to be up to 1.5
inches between Warrendale to east Cascade Locks and extending across
the river to the Washington side. Eastern Skamania County and Hood
River County will probably see more in the way of snow, with up to a
foot in some locations. Areas around Trout Lake may end up with close
to two feet of snow by late Thursday. The NAM insists that onshore
low-level flow makes to the Central Gorge Thu afternoon. Current
Winter Storm Warning runs through 00Z Fri, but future shifts can
adjust timing if necessary.
The cold frontal portion of this system is expected to push inland
Thu. The GFS indicates an area of 150-200 J/kg CAPE associated with
the front developing in the Willamette Valley Thu afternoon. NAM
model soundings are not that impressive, with a general
unidirectional wind field. However, there is some decent speed shear
in the 0-6m layer. An additional concern is the secondary trough that
swings through the waters late Thursday night and then reaches the
coast Fri morning. The NAM and GFS suggest a bent-back occlusion
situation. These have been notorious for producing strong wind,
especially along the coast. The NAM does indicate 50 kt 900 mb wind
speeds along the coast 12Z Fri. This will be much easier to mix down
as the air mass becomes more unstable. There is also potential for
isolated thunderstorm development, mainly over the waters and along
the coast late Thu night through Fri morning. The upper trough
finally moves through the area Fri afternoon. The GFS has 20-30 kt
850 mb west flow into the Cascades Fri. Coupled with dyanmics
associated with the upper trough, snow advisory amounts are possible
for the Cascades. High pressure begins to spread into the Pac NW Sat.
However, will need to keep a mention of showers through at least
early Sat afternoon. Any lingering showers in the late afternoon
should be confined to the far north. Weishaar
.LONG TERM...Saturday Night through Wednesday...Upper level ridging
moves in for the first half of the long term period which will usher
in a period of quiet, dry weather into the beginning of next week.
ECMWF and GEM keep weather dry into Wednesday morning, however the
GFS brings a shot of rain into the area Monday Night/Tuesday. All 3
models are consistent cutting off an upper low underneath the ridge
and swinging it through on Tuesday, but the GFS brings better
moisture with it and actually pushes the wave inland. Have added
slight chance PoPs to the Monday night/Tuesday timeframe, but most
likely solution is still the dry ECMWF/GEM. Otherwise, freezing
levels look like they will push up to the 7000 to 9000 ft range
towards the middle of next week which won`t be great for ski
resorts, although it is possible the Portland area could see its
first week with multiple 50 degree days since November. /Bentley
&&
.AVIATION...A low pres system is approaching the coast, with an
associated warm front working its way north through the region
today. Rain is beginning to let up somewhat now, but cigs and
vsbys remain restricted at most locations, generally a mix of IFR
and MVFR. Think that conditions may improve somewhat later this
evening and overnight as the warm front lifts further north and
we sit in southerly flow in the warm sector of the system. Expect
decreasing rain with cigs lifting to VFR for the interior TAF
sites. The coast may remain predominantly MVFR overnight with
steadier rain. Southerly winds will become gusty overnight into
early Thu AM, especially for the coastal TAF sites, where gusts
of 40 to 45 kt are expected. A cold front will push onshore late
Thu morning and move through the interior during the afternoon.
Expect rain rates to increase ahead of and along the cold front,
with conditions dropping to mainly MVFR.
Colder air in the Columbia Gorge will maintain freezing rain
into Thu. Expect higher mountains to be obscured in clouds and
pcpn into tomorrow as well.
KPDX AND APPROACHES...Expect a mix of IFR and MVFR conditions
through the afternoon and early evening with occasional rain or
drizzle. Think conditions may improve to VFR later this evening
and overnight with decreasing rain. Winds will continue to gust
to around 25 kt out of the E-SE at the surface, and southerly
winds will increase significantly later tonight. This may create
some low-level wind shear concerns through Thu morning. Expect
rain to increase and conditions to deteriorate to MVFR by 12Z-15Z
Thu as a cold front approaches. Pyle
&&
.MARINE...A low pres system currently centered around 40N/140W
will bring a Pacific frontal system into the Pac NW tonight and
Thu. The leading warm front has been working north through the
waters today, and is currently draped over the northern waters.
Southerly winds are now picking up in the warm sector on the
frontal system, with buoy 46050 showing winds bordering on low-
end gales. Expect winds to continue gradually increasing later
this afternoon and this evening. A secondary low will form along
the main frontal boundary and approach the coast from the
southwest tonight. This will enhance the southerly winds
overnight into Thu morning. Based on the latest model runs,
decided to expand the Storm Warning for all of the coastal waters
from late tonight through Thu morning. The strongest winds still
appear to be along the central OR coast, where gusts of 50 to 55
kt are likely. Think there will be enough gusts into the low 50s
over the northern waters to justify a warning, but the main
impacts should generally remain south of Tillamook.
The cold front will push onshore during the mid to late morning
hours Thu. Expect a burst of winds over the inner waters early
tomorrow morning just ahead of the cold front as the surface pres
gradient open up a bit to allow a slight westerly component to
the flow. Winds subside somewhat Thu afternoon and evening behind
the cold front, but still expect low end gales to persist. The
main parent surface low and a bent back occlusion will move
through the waters late Thu night and Fri morning. This will
bring stronger W-SW winds, which should be at least high-end gale
strength. We may need to consider another storm watch for this
this time period depending on how the next couple of model
cycles trend. The low is modeled to move onshore along the
central WA coast Fri morning. Winds then begin to subside later
Fri, and especially over the weekend as higher pres builds over
the waters.
Seas have built into the low teens this afternoon in response to
the increasing winds. They will continue to build trough this
evening and overnight, peaking in the low 20s late tonight into
early Thu morning. The seas will be mainly wind wave and fresh
swell driven, so periods will be fairly short. The seas should
drop back into the teens Thu afternoon, but may remain above 15
ft through Thu night as gales continue. Seas may again approach
20 ft with the approach of the surface low early Fri. Then seas
drop steadily later Fri through the weekend. Pyle
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 4 PM PST Thursday for Central
Columbia River Gorge-Upper Hood River Valley.
Ice Storm Warning until 10 AM PST Thursday for Western Columbia
River Gorge.
Flood Watch through late Friday night for Cascade Foothills in
Lane County-Central Coast Range of Western Oregon-Central
Oregon Coast-Central Willamette Valley-Coast Range of
Northwest Oregon-Greater Portland Metro Area-Lower
Columbia-North Oregon Coast-Northern Oregon Cascade
Foothills-South Willamette Valley.
High Wind Warning from 10 PM this evening to 10 AM PST Thursday
for Central Oregon Coast-North Oregon Coast.
Coastal Flood Advisory from 9 AM to 2 PM PST Thursday for North
Oregon Coast.
WA...Winter Storm Warning until 4 PM PST Thursday for Central
Columbia River Gorge-South Washington Cascades.
Ice Storm Warning until 10 AM PST Thursday for Western Columbia
River Gorge.
Flood Watch through late Friday night for Greater Vancouver
Area-I-5 Corridor in Cowlitz County-South Washington
Cascade Foothills-South Washington Coast-Willapa Hills.
High Wind Warning from 1 AM to 10 AM PST Thursday for South
Washington Coast.
Coastal Flood Advisory from 9 AM to 2 PM PST Thursday for South
Washington Coast.
PZ...Storm Warning from 10 PM this evening to 10 AM PST Thursday for
Coastal Waters from Cape Shoalwater WA to Florence OR out
60 nm.
Gale Warning until 10 PM PST this evening for Coastal Waters
from Cape Shoalwater WA to Florence OR out 60 nm.
Small Craft Advisory for Rough Columbia River Bar until 6 PM
PST this evening.
Small Craft Advisory for Rough Columbia River Bar from midnight
tonight to 6 PM PST Thursday.
&&
$$
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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. The area is
commonly referred to as the forecast area.