Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/20/20
Area Forecast Discussion
National Weather Service Amarillo TX
522 PM CST Wed Feb 19 2020
00Z TAF Cycle
VFR conditions expected at the Amarillo TAF site until around 08Z
Thursday and then MVFR to IFR conditions through around 18Z
Thursday. VFR conditions expected to return to the Amarillo TAF
site after 18Z to 20Z Thursday. Snow is expected at the Amarillo
TAF site between about 06Z Thursday and 15Z Thursday. Winds will
be southeast to east 5 to 15 knots and then becoming north to
northeast 10 to 20 knots after 08Z Thursday.
VFR conditions expected at the Dalhart TAF site until around 06Z
Thursday and then becoming MVFR to IFR after 06Z with VFR
conditions expected to return after 21Z Thursday. Snow is expected
at the Dalhart TAF site between about 06Z and 15Z Thursday.
Southeast to east winds 5 to 15 knots becoming north to northeast
10 to 20 knots after 06Z Thursday.
VFR conditions expected at the Guymon TAF site until around 06Z
Thursday and then becoming MVFR to IFR between about 06Z and 20Z
Thursday. VFR conditions are expected to return after 20Z to 23Z
Thursday. Snow expected at the Guymon TAF site after 06Z until
around 12Z Thursday. Southeast to east winds 5 to 15 knots and
then becoming north to northeast 10 to 20 knots after 06Z
Thursday. The north to northeast winds will diminish to around 5
to 15 knots after 20Z Thursday.
.PREV DISCUSSION... /Issued 402 PM CST Wed Feb 19 2020/
SHORT TERM...Today through Tomorrow...
Current RAP analysis shows the midlevel shortwave disturbance
digging across northern California. Models show this positively
tilted weak wave crossing Nevada and Utah this afternoon and
tonight before continuing eastward across and out of the plains by
tomorrow evening. Weak disturbances advected ahead of the wave,
along with PVA will assist in getting the winter precipitation
started in the Oklahoma Panhandle. An associated cold front will
dive south through the Oklahoma Panhandle around 00z and be
through the Texas Panhandle by 06z. Weak frontogenesis will
provide additional ascent for a few hours, mainly in the north
northwest portions of the Panhandles as the cold air filters into
the area. Towards the 06z to 12z time period, the exit region of a
jet streak will set up over the Panhandles with additional
dynamics from the ageostrophic component. This may result in
higher snowfall rates for this period of time.
Dynamics are important, but so is the moisture source. A surge of
midlevel moisture from the Pacific will fill in the area, but as the
wave moves east the moisture shifts south, dry air overtakes the
midlevels. NAM soundings from 06z to 12z show where moisture will
fill in the column from the surface to 500-600mb. The lower levels
will continue to remain saturated for slightly longer, leading way
for lingering dendrites to reach the surface after 12z. The moisture
will eventually subside in the mid-morning hours from north to south.
With cloud cover all day today and continuing through the night,
surface temperatures will likely take longer to cool until
precipitation begins. With temperatures potentially above freezing
at the surface, there is a chance to see rain/freezing rain before
transitioning to snow. Once precipitation begins and temperatures
begin to wet bulb, below freezing temperatures will quickly arrive
and remain through the night and into tomorrow morning as colder air
filters in behind the front. Onset of precipitation will be as early
as 00z to 03z tonight in the western Oklahoma Panhandle and
northwestern Texas Panhandle. After 06z, the chance for
precipitation will remain in the northwest and begin to linger
south. Approaching the morning hours, precipitation will begin to
diminish from north to south with all precipitation ending by 18z.
The northwest Panhandles will see snow amounts of 1 to 3 inches with
the remaining Panhandles having the potential to see zero to an inch
of snow. Locally higher amounts are possible, especially in the
northwest where temperatures have the chance to wet bulb faster and
precipitate earlier, along with marginally better dynamic forcing.
Behind the front winds will be 10 to 20 mph with the potential to
see some blowing snow tomorrow morning. Cloud cover will remain
through the early evening hours tomorrow before starting to clear,
with high temperatures to remain in the 30s. However, in the far
southeast where little precipitation is expected, temperatures may
rise into the lower 40s.
LONG TERM...Thursday night through Wednesday.
Benign weather is expected Thursday night through Friday night as
the forecast area awaits the next upper level storm system. This
particular upper level low pressure system is progged to move from
southern CA on Saturday morning eastward to the four corners
region and across the southern high plains by late Sunday
afternoon. Pops return to the OK and TX Panhandles Saturday into
Sunday. The atmospheric temperature profile associated with this
next storm system will be on the warm side. Therefore, precipitation
should remain all liquid Saturday into Sunday.
Dry weather returns for Sunday night through Monday night. Another,
colder upper level trof is then forecast to affect the region
around next Tuesday, with the corresponding cold front expected
to move across the area Monday afternoon and evening. This far out
in time, have utilized a blend of model pops for next Tuesday,
which is basically in the slight chance category.
TX...Winter Weather Advisory until 9 AM CST Thursday for the
following zones: Dallam...Hartley...Sherman.
OK...Winter Weather Advisory until 9 AM CST Thursday for the
following zones: Beaver...Cimarron...Texas.
Area Forecast Discussion
National Weather Service Boston/Norton MA
959 PM EST Wed Feb 19 2020
Winds continue to diminish overnight, but much colder weather
works into the region tonight and Thursday. Below-normal
temperatures continue into Friday, before temperatures return to
above normal levels for the weekend. Above normal temperatures
continue into early next week with the next chance of
precipitation on Monday and Tuesday.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
10 PM Update...
Previous forecast is on track as winds continue to diminish as
large high pressure slowly builds in from the west. Skies were
clear, but should see some clouds work into at least western
MA/northern CT toward daybreak. This is result of some remnant
Lake moisture, but it will remain dry. Cold advection will
continue allowing low temps mainly in the middle teens to lower
20s by daybreak.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
Mid level trough axis approaches from the Gt Lakes with an area of
mid/high level moisture moving through ahead of it, especially near
the coast. In addition, cross sections show considerable low
level moisture developing. Result will be more cloud cover but
should see partial sunshine. Highs will range from the upper 20s
to mid 30s but winds with considerably less wind than today.
Trough axis moves through with high pres building into New Eng.
Expect clearing skies and light winds which will result in a cold
night. Lows will drop into the single numbers in many locations,
except teens closer to the coast and in the urban centers.
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
* Below normal temperatures continue on Friday, but begin to rebound
Friday night. Temperatures trending upward into early next week.
* Dry through much of the long term. Next shot of precipitation is
Monday into Tuesday. Looks like mainly rain at this point in time,
but it is still too early to determine the specific details.
A trough will be located just offshore of New England early on
Friday, while a ridge axis is situated over the Great Lakes region.
The ridge will gradually build into New England on Friday while the
trough lifts further offshore. Good agreement amongst guidance with
the 850 hPa ridge sliding through by the afternoon. This shifts
winds aloft from northwesterly cold air advection to a westerly
direction, which advects warm air in.
This happens a bit too late to impact the high temperatures on
Friday. So it still will be colder than normal with temperatures
ranging from the 20s across the higher elevations to the low 30s
along the coast. Dry and quiet weather continues.
Friday night through Sunday Night...
The dry and quiet weather persists with good agreement amongst
guidance. High pressure shifts from the Southeast US offshore late
on Saturday into Sunday. Temperatures will trend upward due to
southwesterly warm air advection aloft with 0 to +2 degree Celsius
850 hPa air moving in. High temperatures on Saturday range from the
30s across the higher elevations to the low to mid 40s along the
coast. Readings on Sunday range from near 40 across the higher
elevations to near 50 degrees along the coast.
Monday and Tuesday...
Next shot of precipitation is on Monday into Tuesday. High pressure
builds well offshore. A cutoff low is progged to lift from the
Central Plains late on Sunday northeastward into the Great Lakes
Region. A surface low develops somewhere from the Mississippi River
Valley to the Southeast US and lifts northeastward. Still some
significant timing differences with the GFS/ECMWF being much slower
than the latest GEM guidance. Run-to-run differences suggest things
trending slower, but being this far out this trend could change.
Kept the NBM guidance at this point in time. Looks like mainly rain,
but will need to hammer down ptype details once we get closer to the
Temperatures remain mild with highs on Monday and Tuesday ranging
from the 40s to the low 50s. Expect the warmest readings along
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
VFR conditions expected through the forecast. A trough swings in
from the Great Lakes bringing bringing 4-6 kft ceilings in
western MA. This will gradually expand across southern New
England through Thursday. Well captured by the latest RAP RH at
Tonight...High confidence on the trends, but moderate confidence
on the timing of when gusty winds end. NW winds diminishing
overnight. Thinking roughly between 02-06Z per RAP/NAM and GLAMP
guidance. Winds remaining NW.
Thursday...High confidence. Gusty winds redevelop, but will not
be as gusty as today. Should see gusts around 15-20 kts once the
mixed layer develops between 13-15Z. Gusts end during the
evening once the mixed layer decouples. Roughly between 22-02Z.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Thursday Night through Monday/...
Thursday Night through Saturday: VFR. Breezy.
Saturday Night through Sunday Night: VFR.
Monday: Mainly VFR, with areas MVFR possible. Chance RA.
Gradually diminishing wind as gradient relaxes. 25-30 kt gusts this
evening, dropping to 15-20 kt by late tonight.
Thursday and Thursday night...High confidence.
Winds mostly below SCA with NW gusts 15-20 kt
Outlook /Thursday Night through Monday/...
Thursday Night through Friday Night: Winds less than 25 kt.
Seas locally approaching 5 ft.
Saturday: Winds less than 25 kt. Areas of seas approaching
Saturday Night: Winds less than 25 kt. Seas locally approaching
Sunday through Sunday Night: Winds less than 25 kt.
Monday: Winds less than 25 kt. Chance of rain.
MARINE...Small Craft Advisory until 4 AM EST Thursday for ANZ231>235-
Small Craft Advisory until 1 PM EST Thursday for ANZ250-254.
Small Craft Advisory until 7 AM EST Thursday for ANZ255.
Area Forecast Discussion
National Weather Service State College PA
1052 PM EST Wed Feb 19 2020
A large area of Canadian high pressure will move southeast to
the Lower Mississippi and Tennessee Valleys by early Saturday,
dominating our weather with mainly dry and and seasonably cold
conditions through Friday. Just a few flurries will fly across
the northern tier this afternoon into Thursday morning.
A weak mid and upper level disturbance will move east and tap
limited low level moisture off the Great Lakes, bringing the
chance of snow showers across the Northwest half of the state
Thursday with a light coating of snow possible across the
Northwest Mountains and Laurel Highlands.
The coldest day will be Thursday as high temperatures stay
about 10 to 15 degrees below normal.
A gradual warming trend will follow for the upcoming weekend
with a continuation of dry weather. The next chance for
precipitation, mainly in the form of rain, will come Monday
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Skies will be mainly clear through early tonight, before a deck
of thick altocu and altostratus races east from the midwest and
spreads across mainly the NW half of the CWA toward daybreak.
WNW Wind will diminish this evening to 10 kts or less. Lows
tonight will vary from the teens across the Northern Mtns and
Laurel Highlands to the low- mid 20s in the SE.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
RAP soundings show a thick shield of mid level clouds covering
much of the NW half to two thirds of the state, with cloud bases
dipping into the 3.5-5 kft AGL range for a few to several hours
during the day Thursday. Stratocu beneath this cloud layer and
the lower part of the mid clouds will have temps in the
favorable -12 to -18C range for dendritic growth, leading to
the chc of flurries from late morning on. The very dry llvl air
and scattered-bkn higher cloud bases across the Lower Susq
Valley will cause any flakes to vanish before reaching the
Expect 925mb temps to drop to the -6 to -12C range for Thurs
aftn. Thu/thu night will be the absolute min for temps this
week as the ridge of high pressure extends ENE from its center
over the Mid Miss Valley. Maxes only around 20F in the
northwest and m30s in the SE will be anywhere from 7 to 18F
Skies will become mainly clear Thursday night with temps diving
into the single digits across the north, around 10F across the
Laurels, and Teens throughout the Central and SE zones.
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
High pressure centered over the southeast United States will
result in an absolutely gorgeous weekend across the Commonwealth
with 3 straight days of blue sky. After a colder-than-average
Friday, a warming trend is expected through Sunday as
gusty west-southwesterly winds usher in milder temperatures
As we round out meteorological winter next week, an unsettled
pattern returns with a series of weather systems affecting
the Commonwealth. The first system arrives Monday evening as
rain showers overspread from west to east along a weak cold
front. Simultaneously to the cold front`s arrival, a low
pressure system tracking east from the Southern Plains will
funnel moisture into the northeast during the day on Tuesday.
The majority of guidance favors an all-rain solution in
Pennsylvania as the 500mb trough preserves neutral tilt and cold
air is unable to funnel in. Slightly colder and closer-to-
seasonable air settles in for the midweek with gusty winds
likely between systems.
Though it is beyond the scope of this forecast, storm number 2
arrives late Wednesday into Thursday. Details for this storm
are still highly uncertain, but models indicate the potential
for a rapidly- deepening system affecting the mid- Atlantic.
Additional details will be provided in the coming days. Behind
that system, it appears Arctic air may finally settle into the
middle-Atlantic. As such, the CPC favors below-normal
temperatures in the latest 8-14 day outlook.
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
Northwest winds will diminish to under 10 mph this evening with
mainly clear skies. Mid level clouds will race in from the west
later tonight and persist through Thursday.
A period of MVFR is expected at BFD overnight through Thursday
midday because of lake induced clouds as winds shift to more
northwesterly. Elsewhere, VFR conditions will persist through
the forecast period.
Fri-Sun...Mainly VFR conditions anticipated as a large area of
Canadian high pressure moves southeast to the Central
Appalachians by Sat morning.
Mon...increasing clouds with a chance of light rain late Monday
into Tuesday Central and SE, and rain or wet snow over the NW
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
817 PM CST Wed Feb 19 2020
Issued at 304 PM CST Wed Feb 19 2020
H5 analysis from earlier this morning had a closed low
over northern portions of Quebec. a trough extended south of this
feature into southern Quebec. Another trough of low pressure extended
southwest from southwestern Ontario into eastern Idaho, while a
ridge of high pressure extended from the Pacific NW coast, north
into western portions of the NW Territories of Canada. Across
western and north central Nebraska, intense mid level frontogenesis
has developed across the Sandhills this morning and has spread snow
to the Sandhills and swrn Nebraska. Some of this has had intensities
of up to a half to three quarters of an inch per hour across the
central Sandhills. As of 2 PM, snow amounts ranged from around 2
inches at North Platte, to 5 inches at Thedford, Halsey, O`Neill and
around Arthur. In addition to these reports, a 6 inch report came
out of far southwestern Hooker county around 11 am CT this morning.
Though we haven`t received an additional report from this location,
based on radar returns over the past 2 to 4 hours, wouldn`t be
surprised if we see some 8 inch reports along the McPherson/Hooker
county line, east to around Dunning. Skies remained cloudy this
afternoon with some limited clearing noted along the SD/Nebr.
border. Temperatures as of 2 PM CT ranged from 12 at O`Neill to 22
Issued at 815 PM CST Wed Feb 19 2020
The accumulating snow has ended across southwest and north central
Nebraska. The Winter Weather Advisory has been cancelled.
The RAP and HRRR models indicate widespread subzero temperatures
by morning with readings around 5 below zero. The RAP model
indicates precipitable water falling to less than 0.10 inches
which is backed up the 00Z UNR upper air flight which indicates
0.09 inches of water. This will support tremendous radiational
cooling across the blanket of fresh snowfall covering parts of wrn
and ncntl Nebraska.
Before this dry air moves in, areas of southwest Nebraska and the
Sandhills will be prone to patchy fog as suggested by the short
term model blended visibility product.
The forecast has been updated for flurries this evening, subzero
temperatures and patchy fog. Wind chill readings near 20 below
zero are possible by morning.
.SHORT TERM...(This evening through Thursday night)
Issued at 304 PM CST Wed Feb 19 2020
Based on the latest HRRR and NAM12
solns, snowfall is expected to end fairly quickly this evening. By
00z, the best chances for snow will be confined to areas along and
south of highway 92. By Midnight, snow is expected to end across all
of southwestern Nebraska. Given the degree of snow which has already
accumulated, as well as forecast snow for this evening, decided to
cancel the winter weather advisory for Deuel, Chase, Perkins, Hayes
and Frontier counties. In these areas, little or no snow fell today.
With forecast snow accums of less than an inch in these areas this
evening, feel no need for a winter weather advisory in these areas.
Overnight, skies will clear overnight as a strong 1045mb high builds
into northern Iowa. Fresh snowcover and light winds will make for
bitterly cold temperatures tonight. For lows tonight, started with a
blend of MET and MAV guidance, then lowered temps across the board a
couple of degrees. On Thursday, winds will shift around to the west
and southwest as the high builds into southern Iowa and northern
Missouri. Even with the westerly winds, temperatures will remain
cold thanks to H85 temps of -3 to -8C along with fresh snow cover.
Once again, went ahead and undercut guidance for highs Thursday as
widespread snow cover is expected. Lows Thursday night will be
seasonal in the teens, as southerly winds are expected not to
totally de-couple overnight.
.LONG TERM...(Friday through Wednesday)
Issued at 304 PM CST Wed Feb 19 2020
Benign weather is expected for Friday
through Saturday. A warm front will push into the region Friday with
H85 temps reaching into the single digits C Friday afternoon. Even
warmer air will push into western and southwestern Nebraska
Saturday. With H85 temps reaching into the lower teens, we even may
see some lower 60s in the southwestern forecast area Saturday
afternoon. The tranquil weather pattern will be short lived though.
A southern stream trough and closed low will track into the Four
Corners Saturday night, emerging onto the plains of eastern Colorado
Sunday. As for the track of this system. It has trended north over
the past 24 hours. That being said, locations south of the
Interstate could see some rainfall or accumulating snow given the
current track of the low as depicted in the models. Have introduced
some low pops across the southern forecast area. Precipitation types
will be problematic with this system, as arctic air remains well
north of the system over southern Canada. Based on the current temp
forecast, we could see rain during the day and snow in the nighttime
hours. A second system will cross the central CONUS during the
middle of next week. As was the case yesterday, both the mid range
solutions indicate a midweek system, albeit now much weaker,
crossing the central Conus next week. Impacts from the system
continue to remain up in the air as the intensity of the system and
synoptic setup are uncertain right now. Will need to monitor this
one over the next several days.
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 630 PM CST Wed Feb 19 2020
Snow is ending from the north and VFR is taking hold across the
region. Some late night fog could develop across the recent snow
cover, but confidence is not high and have not included in the TAF
at this time. Winds overnight will be light. VFR is expected to