Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/29/24
Area Forecast Discussion
National Weather Service Boston/Norton MA
1036 PM EST Wed Feb 28 2024
.SYNOPSIS...
A strong cold front will bring numerous showers and strong wind
gusts into this evening, followed by sharply falling
temperatures and a brief changeover to snow with minor
accumulations possible in the higher elevations. Dry Thursday,
but windy and colder than normal. High pressure builds in on
Friday. This moderates temperatures and brings lighter winds.
Unsettled this weekend and perhaps into early next week.
Considerable uncertainty on how things evolve, but temps appear
to be near to above normal.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
No major changes to the forecast this evening. tracking a fine-
line of convection as it moves east across southern New England.
Expecting this fine-line to be offshore of the Cape sometime
between 11 PM and midnight. This fine-line should pass by
Nantucket before 1 AM.
Have seen peak reported gusts of 55 to 65 mph with this fine
line. More commonly though, gusts were more in the range of 45
to 55 mph.
The other impressive thing is the temperature drop behind this
line. Temperatures at Orange MA dropped about 10 degrees in an
hour. By daybreak, still thinking temperatures there will drop
another 15 degrees. A similar story elsewhere across southern
New England. Expecting low temperatures to be 15-30 degrees
lower from the present readings at 1030 PM this evening. The
largest drop will be across RI and southeastern MA, where the
leading edge of the colder air has yet to arrive.
Liked the latest consensus timing for the precipitation from the
HRRR, RAP and NationalBlend. expecting all precipitation to be
offshore by 4 AM, with the western half of southern New England
mainly dry by 1 AM.
730 PM Update...
Have upgraded the Wind Advisory across the rest of western and
portions of central MA to a High Wind Warning. This is based on
the latest obs across eastern NY along with latest short term
high res guidance. Bumped up our gusts toward the latest HRRR
through roughly 06Z as it is doing well based on obs.
Previous discussion...
Key Points...
* Strong to potentially damaging wind gusts expanding across
rest of southern New England tonight as winds shift to the
west
* Sharply falling temperatures tonight, with rain changing to a
brief period of snow before ending. Minor snow accumulation
possible over the higher elevations
Scattered to numerous pre-frontal showers will continue to move
across SNE through the afternoon into early evening within the deep
moist SW flow. Temporary lull in the strongest wind gusts this
afternoon but wind will be ramping up again late today and this
evening near the south coast as secondary low level jet develops to
the south and strengthens as it expands across SE New Eng. Some
uncertainty on strength of the low level jet as hi-res guidance is
considerably stronger than global guidance and there is also quite a
bit of variation among the hi-res sources. Taking a blend would
suggest a 75-85 kt low level jet peaking 00-03z over Cape Cod and
Islands.
Soundings show a low level inversion which adds uncertainty to the
wind gust forecast. Hi-res guidance has temps in the mid 50s and
perhaps upper 50s across SE coastal MA and the upper Cape which will
help to erode the inversion and increase potential for damaging wind
gusts to 60+ mph, with 45-55 mph gusts near the south coast into SE
MA. Any convective showers may also help to bring stronger wind
gusts to the surface. The high wind warning for Cape/Islands
Attention will then shift to the strong cold front passage this
evening. The front is moving through western NY with a fine line
accompanying it. The front will sweep through the region between 8
pm and midnight. All the hi-res CAMs show a weakening fine line
moving into western NY then further weakening as it moves east. This
is a reasonable expectation given the pressure rise-fall couplet is
weakening and instability is limited. However, it is still a strong
rise-fall couplet which will bring strong wind gusts with the fropa
as winds shift to west. Boundary layer quickly deepens behind the
front in the increasing cold advection with low level lapse rates
approaching dry adiabatic. Expect strongest west wind gusts in
western MA where 50-60 mph gusts likely. A few 60+ mph gusts
possible in the Berkshires where we upgraded to a high wind warning.
The magnitude of wind should decrease further E with wind gusts to
45-55 mph behind the front.
The cold front will be followed by a sharp temp drop with temps
falling from the 50s through the 30s in a 2-4 hr period, with
morning lows ranging in the 20s. Wind chills will drop into the
teens by morning with single numbers in the higher terrain. Rain
will flip to a brief period of snow before ending as rapid drying is
moving in from the west. Accumulations will be limited to a coating
to an inch, especially higher elevations and potentially up to 2
inches in the Berkshires. There is a low risk for isolated icy spots
as temperatures drop, especially where any minor accum occurs, but
otherwise not a big concern as strong winds and rapid drying will
dry out pavement before any freezing.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Thursday...
Mid level trough swings through New England with an accompanying
cold pool aloft and area of low-mid level moisture. So sunshine will
be followed by sct-bkn diurnal cu developing by midday. While dry
weather is expected, some of the guidance is indicating a few lake
effect snow showers may extend into the Berkshires. W-NW winds will
remain gusty with well mixed boundary layer supporting 30-40 mph
gusts, possibly a bit stronger over the higher elevations. 925 mb
temps -8C to -10C so a cold day with below normal temps. Highs will
be in the low-mid 30s, except upper 20s over the higher elevations.
Thursday night...
Mid level trough axis moves to the east with high pres building in
from the west. Mainly clear skies with diminishing wind will lead to
good radiational cooling. Lows will drop into the teens and lower
20s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Highlights
* Dry and quiet weather to end the week. Temperatures trending
near/slightly warmer than seasonable.
* Unsettled this weekend through early to mid next week. Though
details are hazy especially for Sun into mid next week.
Temperatures near to above normal.
Friday...
A ridge axis builds from the OH Valley into the central Great Lakes
early on Fri. This builds into the eastern Great Lakes by late in
the day. Behind the ridge, a shortwave lifts into the OH
Valley/central Great Lakes. High pressure builds into/south of our
region on Fri, but will shift offshore late in the day.
Quiet weather anticipated across southern New England to end the
week. Temperatures will be rebounding to near/above seasonable
levels with SWly flow. Temps at 925 hPa warm to +/- 1 degree
Celsius. Highs top out in the 40s. Will not be as windy as the high
relaxes the pressure gradient.
Friday Night through Tuesday...
A shortwave will lift from the central Great Lakes Fri night into
the Mid Atlantic/eastern Great Lakes by Sat AM. The shortwave slowly
lifts into New England by late on Sat. The shortwave could continue
lifting northeastward into Sun, but some uncertainty on this as some
guidance cuts this feature off to our south/southeast Sun into early
next week. A frontal boundary will be nearby our region to the
south/southeast through this timeframe.
A fair amount of uncertainty with how things will evolve through
this timeframe. The GFS/GEM along with the GEFS/GEPS guidance move
the shortwave along into the Gulf of ME by Sun AM. A ridge builds in
behind it before another shortwave lifts in early next week. The
ECMWF along with the EPS guidance cuts off the wave nearby/south of
our region into early next week. Most confident in rain shower
chances Fri night through Sat at this point. Though am uncertain on
the intensity and amounts. The GFS/GEM/NAM/ICON along with the
GEFS/GEPS bring a low along the front into southern New England,
which brings heavier rain showers to our region into Fri Night
through Sat Night. The ECMWF/UKMET along with the EPS are not as
progressive with the wave. This brings the low in much more slowly,
so will still have rain showers, but not as intense with lower
totals into Sun AM. Given this, did keep our precip chances to
chance/likely in this period. This will also have implications on a
S/SEly low level jet as the GFS/GEM/GEFS/GEPS could bring some
stronger winds to our area in comparison to the EC/EPS solutions.
After Sat Night confidence in the forecast lowers significantly due
to the handling of the shortwave. Not really sure if the progressive
solutions (GEFS/GEPS) are the way to go, which would keep us drier
and warmer. Likewise the EPS is much slower to push the wave
through. This would keep us unsettled and cooler with prolonged
onshore flow. Due to the differences have stuck with the NBM at this
point, which keeps slight chance to chances of precip late in the
weekend into early/mid next week. Stay tuned as hopefully we will
have a better idea how things will evolve as we get closer. The NBM
could be running a bit too warm in this timeframe especially if the
prolonged onshore flow solutions are correct.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight...High confidence in trends, moderate in timing.
IFR to MVFR ceilings with rain showers and strong S/SSW winds.
Could have visibilities as low as 1-3/4 SM visibility in areas
of heavier showers. A cold front will sweep across the region
between 02-08Z tonight, which will shift wind rapidly to the
W/NW. Right ahead of the front there will be moderate rain, and
a quick hit of snow just following the front. A dusting to up to
1 inch of accumulation is possible. Amount of 1 inch are most
likely across the higher terrain.
S/SSW winds ahead of the front gusting to 35-45 kt. Strong
winds aloft will mix to the surface with the front, with gusts
to 50 kt possible. Strong LLWS (speed shear) much of this
evening and early Thursday morning. LLWS as high as 60 to 70
kt, strongest across the Cape and Islands. Winds shift
dramatically to the WNW behind the front, gusting to as much as
30-40 kt through 12Z.
Thursday... High Confidence
VFR with gusty WNW winds, 15-25 kts and gusts 30-40kts. Cold
pool aloft will generate some mid level cumulus, between 4 to 6
kft. Winds peak during the morning hours and diminish slightly
during the afternoon.
Thursday night... High Confidence
Diurnal CU dissipates early evening as the sun sets, leading to
a mainly clear evening. VFR. Winds W/WNW 10-15kt gusting to 15
to 20kt.
KBOS TAF...High confidence in trends, moderate in timing.
MVFR to IFR conditions with rain showers this evening, strong
S/SSW winds and LLWS. Cold front slides through roughly 05-07Z
and winds rapidly shift to the W/WNW with gusts of 45 to perhaps
50 kts. As the front slides through will have snow mixing in
for a brief period before precip ends. No accumulation
anticipated due to warm antecedent conditions. Winds diminish
slightly Thursday afternoon before eventually dying back to less
than 20 kt Thursday night. Diurnal cumulus around 4-6 kft will
be present much of the day Thursday.
KBDL TAF...High confidence in trends, moderate in timing.
IFR ceilings to start with rain showers. A cold front
approaches and crosses the terminal between 01-03Z tonight,
bringing the chance for heavy rain and post frontal snow showers
for a brief period. Snow accumulation not expected given warm
antecedent conditions. Winds shift dramatically from the SSW to
the WNW behind the front and rapidly improve to VFR. Gusts to
50 kt not out of the question with the front, but between 30
and 40 kt ahead of and behind the front. Winds diminish
slightly Thursday afternoon before eventually dying back to less
than 20 kt Thursday night. Diurnal cumulus around 5 kft will be
present much of the day Thursday.
Outlook /Friday through Monday/...
Saturday: Mainly VFR, with areas IFR possible. Breezy. SHRA
likely.
Saturday Night: Mainly VFR, with areas IFR possible. Breezy.
Chance SHRA.
Sunday: Mainly VFR, with local IFR possible. Slight chance
SHRA.
Sunday Night: Mainly VFR, with areas MVFR possible. Breezy.
Chance SHRA.
Monday through Monday Night: Mainly VFR, with local IFR
possible. Breezy. Chance SHRA.
Tuesday: Chance SHRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Gale Warnings for all waters into Thursday. Another surge of strong
winds this evening with southerly gusts to 45 kt, then post-frontal
westerly gales after midnight into Thursday. Winds gradually
diminish Thu afternoon through Thu night.
Outlook /Friday through Monday/...
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Rain showers likely.
Saturday Night: Winds less than 25 kt. Seas up to 5 ft. Rain
showers likely.
Sunday: Winds less than 25 kt. Areas of rough seas. Chance of
rain showers.
Sunday Night through Tuesday: Winds less than 25 kt. Seas up to
5 ft. Chance of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 7 AM EST Thursday for CTZ002>004.
MA...Wind Advisory until 7 AM EST Thursday for MAZ005>007-013>021.
High Wind Warning until 7 AM EST Thursday for MAZ002>004-
008>012-022>024-026.
RI...Wind Advisory until 7 AM EST Thursday for RIZ001>008.
MARINE...Gale Warning until 7 PM EST Thursday for ANZ230-250-251.
Gale Warning until 1 PM EST Thursday for ANZ231>235-237-
254>256.
Gale Warning until 7 AM EST Thursday for ANZ236.
&&
$$
SYNOPSIS...KJC/BL
NEAR TERM...Belk/KJC/BL
SHORT TERM...KJC
LONG TERM...BL
AVIATION...BL/KS
MARINE...KJC/BL
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
431 PM MST Wed Feb 28 2024
...New AVIATION...
.SYNOPSIS...
Issued at 1249 PM MST Wed Feb 28 2024
Pacific storm moving across New Mexico tonight will spread a few
showers to the area, with some moderate snow possible over the
Gila/Black Range. Meanwhile the cold front that came through this
morning brought with it the smoke from the Texas Panhandle fires.
Tonight`s showers will continue into Thursday morning before
dissipating. Dry west/southwest flow aloft will keep the weekend
dry, with temperatures warming back up above normal.
&&
.DISCUSSION...
Issued at 1249 PM MST Wed Feb 28 2024
Upper low now over the Sonoran Desert just south of Arizona. Sub-
tropical moisture ahead of the low persists over the eastern CWA
but will continue sliding eastward. HRRR shows showers developing
next few hours over SW New Mexico and spreading north and east the
remainder of tonight. Upper low tracks across the Gila tonight
(where the best dynamics are) so best QPF likely over that area.
Snow levels should remain at or above 7000 feet overnight, so
still expect some moderate snow above that level. Hence winter
advisory will continue for that area. Elsewhere, our back door
front this morning decided to pick up the smoke from the Texas
Panhandle fires and bring it down to our area. The smoke likely to
hang around overnight, unless some showers can help clean the air
up. Otherwise winds turn back more southwest Thursday, helping to
disperse the smoke.
Thursday...clouds and rain should be ending from west to east
throughout the morning, with the Sacs perhaps seeing a shower into
the early afternoon. Temperatures will remain below normal.
Friday and beyond...flow aloft turns more west and southwest
through the rest of the period (Wednesday). Thus, benign weather
through this period with temperatures warming back above normal.
Wednesday looks like a potential rain maker on previous model
runs (mainly the GFS) but even GFS walking this back; now just
showing a weak upper trough moving through, with very little
chance for rain.
&&
.AVIATION...
(00Z TAFS)
Issued at 427 PM MST Wed Feb 28 2024
Compact upper-level storm system is approaching the area this
evening. It will bring scattered to widespread rain showers and
ISO thunder. Thunder was left out of TAFs, but could effect TAF
sites through the evening and overnight hours. VIS may drop below
5 miles with any heavier cells. Predominately however, VFR or
MVFR conditions are expected with CIGs ranging 050-100. Smoke
issues seem to be improving for ELP, so further VIS reductions
are not expected there. Winds will be generally easterly at 10-15
kts with gusts to 25 knots, shifting to the west or southwest
tomorrow afternoon with speeds under 10 knots.
&&
.FIRE WEATHER...
Issued at 1249 PM MST Wed Feb 28 2024
Main fire concern is over now that the winds have subsided. Will
still have some breezy east/southeast winds tonight east of the
Rio Grande Valley but higher RHs should alleviate any fire
concerns. Chance of showers Thursday, then dry through the weekend
and first part of next week. Cool temperatures Thursday will warm
back above normal Friday and the weekend. No significant winds
expected until Sunday, when winds will pick up as an upper trough
moves across the central Rockies.
Min RHs: Lowlands 25-40% Thursday then down to 10-20% Friday
through the weekend. Mountains 50-70% Thursday, then down to
20-30% Friday through the weekend. Vent rates poor-fair Thursday
and Friday, becoming very good-excellent for the weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 43 64 45 73 / 70 10 0 0
Sierra Blanca 37 60 40 67 / 60 10 0 0
Las Cruces 40 62 40 72 / 70 10 0 0
Alamogordo 36 57 36 67 / 80 40 0 0
Cloudcroft 26 39 28 47 / 80 40 0 0
Truth or Consequences 38 59 38 69 / 80 20 0 0
Silver City 35 54 35 61 / 60 10 0 0
Deming 38 63 36 71 / 70 0 0 0
Lordsburg 38 61 36 68 / 70 0 0 0
West El Paso Metro 42 63 43 71 / 70 10 0 0
Dell City 36 61 33 71 / 80 10 0 0
Fort Hancock 39 65 38 72 / 70 10 0 0
Loma Linda 36 57 41 65 / 80 10 0 0
Fabens 41 65 40 72 / 70 10 0 0
Santa Teresa 40 62 39 70 / 70 10 0 0
White Sands HQ 41 62 44 71 / 80 10 0 0
Jornada Range 35 61 34 69 / 80 20 0 0
Hatch 39 64 35 72 / 80 10 0 0
Columbus 41 63 42 71 / 70 0 0 0
Orogrande 35 58 36 68 / 80 20 0 0
Mayhill 27 53 34 62 / 80 30 0 0
Mescalero 28 49 31 58 / 80 50 0 0
Timberon 26 48 29 57 / 80 40 0 0
Winston 31 54 31 62 / 80 10 0 0
Hillsboro 33 59 34 67 / 70 10 0 0
Spaceport 34 59 32 68 / 80 20 0 0
Lake Roberts 31 54 30 61 / 60 10 0 0
Hurley 33 57 34 65 / 50 10 0 0
Cliff 40 61 29 67 / 70 10 0 0
Mule Creek 37 57 24 62 / 80 10 0 0
Faywood 35 57 36 65 / 60 10 0 0
Animas 39 63 37 70 / 80 0 0 0
Hachita 38 62 38 69 / 70 0 0 0
Antelope Wells 37 64 39 72 / 80 0 0 0
Cloverdale 39 58 41 64 / 80 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...Winter Weather Advisory until 5 AM MST Thursday for NMZ426.
&&
$$
FORECASTER...34-Brown
Area Forecast Discussion
National Weather Service Grand Forks ND
613 PM CST Wed Feb 28 2024
.KEY MESSAGES...
- Temperatures moderate to above normal Thursday to Saturday
once again, although confidence in temperatures is low due to
snowpack.
- The probability for warning impacts remains low for this
weekend through early next week (20% chance) due to
uncertainties in intensity and track of the system. Potential
impacts could range from minor (light snowfall accumulations,
light ice accumulations, and blowing snow) to major impacts
(heavy snowfall exceeding 6 inches, blizzard conditions,
accumulating ice).
&&
.UPDATE...
Issued at 613 PM CST Wed Feb 28 2024
Winds are turning to the south along and west of the Red River
Valley, but are still light to the east. So with only some thin
cirrus overhead, there will be a several hour period of rapid
temperature fall east of the Valley. May drop temperatures a
little more there this evening, with the latest HRRR showing 5
below to 10 below possible across northwest Minnesota. 850mb
warm advection is pretty strong overnight, with some mid level
cloud cover expected by late evening and overnight. So this
should help to stop the temperature fall, but until that
develops, temperatures will be dropping (especially across
northwest Minnesota).
&&
.DISCUSSION...
Issued at 136 PM CST Wed Feb 28 2024
Surface analysis at 18z indicates a very large surface ridge up the
Red River Valley stretching all the way south through the
Nebraska/Iowa border. This has led to clear skies and light winds
today. As we progress into the overnight hours and that high
propagates eastward, winds will increase from the southeast. As a
result, warm air advection should allow for modulating temperatures
on Thursday. Snow pack from the previous blizzard should keep
temperatures from achieving their true potential, and thus we may
struggle a bit to erode the current snowpack. Regardless, NBM
probabilities paint an 80% chance to exceed 32 tomorrow and a 100%
chance to exceed by Friday, so some snowpack erosion is likely. A
weak surface low moves through southern Manitoba into
southwestern Ontario Friday into Saturday, allowing for a cold
front to cross the region and cool us down by Saturday.
The biggest concern for the forecast period is the potential for
another winter storm late this weekend into early next week. In the
lead up to this system, strong warm air advection will likely
exist. This does present a window of opportunity for freezing
rain/snow in the Saturday evening/Sunday morning timeframe. This
depends on if forcing arrives while temperatures near the
surface are below freezing. Given the short window,
accumulations should not exceed 0.1" at the worst before a
transition to rain and/or snow.
Impacts from this system should remain heavily tied to the track and
intensity of the low. The potential impacts from this system could
range on the more minor end (light snowfall accumulations, areas of
blowing snow, in addition to the previously mentioned ice
accumulations) to more major impacts (blizzard conditions, heavy
snowfall accumulations, plus the aforementioned ice accumulations).
Clusters over the last few runs have generally favored higher
impacts west of the Red River Valley, with a heavy dry slot straight
down the valley to just east (70% of solutions). Still, there exists
a potential scenario where the upper low cuts off and is much deeper
(30% of solutions) , allowing for heavy snowfall to intrude into the
Red River Valley. Should this scenario arise, it would be hard to
not suggest that blizzard impacts would be likely, as a deep
Colorado low combined with heavy snow would create whiteout from
falling snow alone. Without any real understanding of the trajectory
at this point, the main message right now is that the bulk of the
snow accumulation footprint remains across central North Dakota into
the Devils Lake Basin, although that would shift eastward in the
event of a deeper and cutoff solution.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 613 PM CST Wed Feb 28 2024
The main thing with this set of TAFs is wind speeds and
directions. Light winds to start will become southeast, then
slowly increase through the late night and Thursday morning.
Should see some wind gusts through the mid morning to mid
afternoon, before they decrease again. Other than cirrus, some
mid clouds may form overnight, which could affect KDVL/KGFK/KTVF
and KBJI. However, heights look to be above 8000 feet, so
minimal or no impacts are expected from them.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Godon
DISCUSSION...Perroux
AVIATION...Godon
Area Forecast Discussion
National Weather Service Gray ME
927 PM EST Wed Feb 28 2024
.SYNOPSIS...
Warm and showery conditions through this evening will come to an
abrupt halt as a strong cold front passes through the region.
This will usher in a one day return to wintry conditions on
Thursday as Arctic air pours into the region with high
temperatures running 20 to 25 degrees colder than Wednesday
under gusty northwest winds. Temperatures will quickly rebound
on on Friday and into this weekend...returning to values that
are well above normal for the beginning of March. The next
chance for some rain showers comes Saturday night into Sunday as
low pressure passes south of the region.
&&
.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
923 PM Update...
Continue to issue SPSs for strong and abrupt winds shifts along
a fine line that is tracking through New Hampshire as of 02Z.
Wires have been reported downed across portions of northern New
Hampshire.
Rapid changes in the near term portion of the forecast will
continue tonight as the strong cold front sweeps through the
region. Locally heavy rainfall will be relatively brief with the
passage of the front followed by rapidly falling temperatures.
The front should be east of the region by about 05Z which is
represented well by the latest HRRR.
Update...
Have updated the forecast for the near term portion of the
forecast. Temperatures remain in the 40s across Maine with 50s
in New Hampshire early this evening. Latest radar continues to
show a fine line representing the strong cold front across
Central New York State moving east at about 45 mph. The latest
HRRR solution brings the front across the region during the 01Z
through 05Z time range. Thereafter, blustery northwesterly winds
will usher in much colder air overnight.
Will continue to monitor the rivers for rises and ice movement
tonight.
Prev Disc...
High Impact Weather Potential:
* Strong southerly winds shift westerly with arrival of fine line
associated with the cold front this evening. Locally damaging
winds possible.
* Warm temperatures...rainfall...and melting snow pack may lead to
some river ice movement/ice jam potential.
* Plummeting temperatures bring the risk of slick spots developing
on area roadways.
Pattern: Early afternoon water vapor imagery shows large trough
pushing through the Great Lakes region with an Arctic airmass
pouring into this area behind a strong cold front that is now
working it/s way through New York/Pennsylvania. Ahead of this
feature...there has been showers and fog in the warm advection
regime across our area...however...not much significant
precipitation has fallen except for some good /nearly 1.5"/ totals
along the Midcoast. The primary forecast concerns center around
the frontal passage this evening and the potential for strong
winds along an expected fine-line. Beyond this...the sharply
colder temperatures and refreezing water on roads will be our
concern.
Through this Evening: Showers will continue esp south of the
mountains as temperatures continue to climb in WAA regime. Fine
line of convection now pushing east across central NY and PA will
still be west of our area at 7pm/00Z with temperatures in the upper
40s to mid 50s from NE to SW. Fog has thickened across western
Maine and this will continue for a few more hours before
rain...and then eventual mixing associated with the front
disperses the fog.
Tonight: Cold front crosses the forecast area from west to east in
the 8-11pm timeframe. Short range ensembles and mesoscale guidance
show a diminishing MUCAPE plume ahead of the cold front with perhaps
100-200 J/KG still available over NH. Most of this instability is
elevated with a weak inversion remaining in the llevels. Thus...the
threat for convectively-induced damaging winds appears pretty low
but will continue ISO TSRA mention over NH. However...mixing
improves some immediately ahead and especially right behind the
front so expect any power outage issues due to strong wind
gusts may come within an hour or two of the frontal passage.
Rain may briefly mix with/change to snow before ending with a
coating possible with the greatest chance for this in the
mountains. Otherwise..we/ll watch temperatures crash with single
digit values in the mountains by daybreak...teens and 20s to
the south...with wind chills hovering in the single digits below
zero in the mountains...and the single digits above zero to the
south. There will be a lot of wind...so a true flash freeze
seems unlikely. However...there will be a lot of puddles around
from the rain/melting snow which will refreeze which will
combine with any fallen snow to bring some slick travel
conditions overnight.
No changes to the flood and wind headlines. From 24 hours ago to
today...the wind threat has remained similar while less rainfall
is expected.
&&
.SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY/...
High Impact Weather Potential: Wind gusts over 40 mph with low wind
chills expected.
Pattern: Mobile longwave trough axis overhead to start the day on
Thursday will push east of New England with heights beginning to
build by the afternoon. Deep west northwesterly flow with our
primary forecast concerns centering on winds and wind chills in
the Arctic airmass.
Thursday: Winter returns for a day on Thursday with T8s around -18C
with CAA pretty much over by daybreak. Arriving airmass is very dry
with PWATs below 0.1"/dewpoints falling below zero in spots.
Impressive llevel lapse rates with mixing all the way to H7
indicated in model soundings. There will be a robust pressure
gradient overhead...but winds aloft aren/t overly impressive during
the day with that gradient weakening. Thus...50kt H8 winds around
daybreak decrease to 40kts or less during the day. Expect winds to
remain near advisory levels through the day with the strongest winds
over southern NH and current wind advisory headlines look good.
Despite deep mixing...the chilly airmass will keep highs in the
teens in the mountains...and middle to upper 20s for most other
spots...with a few locations across SE NH and coastal ME reaching
30. The wind will certainly make it feel colder...with wind chills
likely below 0F for much of the day in the mountains...with single
digits and teens to the south.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Latest guidance and bufkit forecast soundings indicate winds will
remain quite breezy with gusts on the order of 35 to 40 mph Thursday
evening into the first part of the overnight hours. Winds will then
follow a downward trend the remainder of the night as broad high
pressure becomes centered near the Mid-Atlantic coast and the
pressure gradient relaxes. That said, winds chills will still be in
the single digits south of the mountains but could fall a few
degrees below at times. Farther north, wind chills are expected to
range from -5F to -15F.
Temperatures rebound quickly for Friday as the high pressure center
moves off into the western Atlantic, setting up a southwest flow.
Good mixing to around 850mb supports wind gusts 20 to 25 mph and
highs reaching the low-mid 40s for SW Maine and central/southern NH.
The winds off the chilly Gulf of Maine will keep the Midcoast and
Augusta regions a bit cooler and in 30s.
For the weekend, temperatures are still expected to run above
normal but may not be as warm as previous forecast. Models are in
decent agreement showing an area of low pressure emerging off the
DELMARVA region later in the day Saturday, and while it`s expected
to remain south of our area, how far north and east it travels is in
question. Either way, an increase in moisture from the south is
looking more probable, which will result in clouds and showers
along with fog, especially across southern and coastal areas.
This would be primarily Saturday into Saturday night per the GFS
as the low moves more out to sea by Sunday, but the ECMWF
stalls the low more to our south, potentially keeping more
clouds/showers through Sunday. If there does end up being more
clouds through the weekend, highs won`t be as warm, but
overnight lows will stay mild.
The weather pattern looks to remain unsettled going into next
week with general agreement amongst the models showing another
weak area of low pressure moving northward, just offshore of the
Eastern Seaboard and approaching New England in the Mon-Tues time
frame along with a cold front approaching from the west. With timing
and location differences of these feature, I haven`t deviated from
the NBM PoPs/temps. With the mild temperatures expected, precip will
be in the form of rain.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term...
Summary: Low clouds...showers...and fog continue through this
evening before a strong cold front passes through the region...with
gusty winds...and rain ending as a few snow showers. Gusty winds
with clearing skies are expected for the day Thursday.
Restrictions: Conditions will continue to deteriorate where they
haven/t already with VLIFR/LIFR/IFR expected in SHRA through
the frontal passage in the 02-06z timeframe. Beyond this...a
brief mix with/change over to snow is possible as precipitation
ends with conditions rapidly improving to VFR within 3 hours of
frontal passage. VFR conditions expected Thursday.
Winds: Southerly winds 10G20kts will strengthen to 20G30kts before
shifting west in the 02-06Z timeframe with gusts to 40kts possible
as this happens. West northwest winds expected beyond this for the
remainder of the period Thursday 20G30kts with some gusts 35-40kts
possible.
LLWS: Southerly winds in the 1.5-2kft layer will remain 40-50kts
through the cold frontal passage in the 02-6Z timeframe. Additional
LLWS is not expected beyond this through Thursday.
Lightning: There is the possibility in the 00-03Z timeframe
this evening for a few lightning strikes across New
Hampshire...with these chances decreasing as you move east into
Maine.
Long Term...VFR through Friday. W/WNW winds will continue to gust to
30 to maybe 35 kt into Thursday evening/night but should mostly fall
in the 15 to 20 kt range by daybreak Friday. Winds turn out of the
SW Friday with gusts 20-25 kt possible in the afternoon. There`s
lower confidence in the forecast this weekend as weak low pressure
could bring low ceilings, fog, and showers to the area. There`s
potential for IFR conditions with southern and coastal terminals
currently favored for seeing more flight restrictions. Another weak
area of low pressure could result in additional flight restrictions
early next week, but confidence is again low.
&&
.MARINE...
Short Term...No changes to marine headlines with MISM1 reaching
storm force gusts today which will continue into tonight with
gale force winds likely to continue through Thursday. Fog will
continue over the waters until a strong cold front shifts the
strough southerly winds to westerly in the 02-06Z timeframe.
Long Term...W/WNW winds will likely continue to gust to or in excess
of gale force into Thursday night over the outer waters, but these
should drop off prior to day break on Friday. Light to moderate
freezing spray is also forecast Thursday night into Friday morning.
There may even be a brief period Friday morning where winds fall
below SCA levels, but a tightening pressure gradient with high
pressure moving into the western Atlantic will result in southwest
winds gusting to 25 to 30 kt from Friday afternoon into early
Saturday. Over the weekend, conditions look to remain generally
below SCA levels, although a wind shift to more easterly or
northerly looks to occur either late Saturday or Sunday with a weak
low pressure somewhere south of the waters. With this flow pattern
over the weekend, would expect to see a return of fog. Another low
pressure system and frontal boundary could bring another period of
increasing winds and seas next week, but timing and location of the
low pressure system is very uncertain.
&&
.HYDROLOGY...
A flood watch remains in effect until Thursday morning. Rainfall
through tonight is expected to be highest along the Midcoast
and in some isolated upslope regions in the mountains. However,
the snowmelt will be the biggest contributor to the total runoff
and flooding potential. The high dewpoints across the region
with increasing winds are supporting rapid melt to an already
ripened snowpack. The snowmelt runoff will be peaking around
the time that the cold front will move in later tonight. The
area can expect 1 to 2 inches of snowmelt runoff, with 0.25 to
0.75 inches of rainfall. The 1 to 3 inches of combined runoff
will peak tonight and could cause small stream flooding,
particularly in the steep slopes in the mountains. Overland
flooding is also possible given the frozen ground conditions
resulting in nuisance road flooding. The sharp temperature drop
early Thursday morning will help shut down the runoff ending the
flood threat. The mainstem rivers will rise but should stay
within banks with a few exceptions into minor levels. Looking
ahead, snowmelt will accelerate this weekend and continue into
next week. This will keep rivers and streams running high over
the next 7 days.
&&
.CLIMATE...
Here`s a look a our record high and record warmest low
temperatures for today.
Date | Portland | Concord | Augusta |
---------------------------------------------------------------------
Weds. | R. High: 58F(2018)| R. High: 65F(1877)| R. High: 51F (2018)|
Feb 28 | R. Low: 36F(2000) | R. Low: 41F(1910) | R. Low: 39F (2000) |
---------------------------------------------------------------------
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Flood Watch until 4 AM EST Thursday for MEZ007>009-012>014-
020>022-025>028-033.
Wind Advisory until 3 PM EST Thursday for MEZ007>009-012-013-
018>020-023>025-033.
Wind Advisory until 5 AM EST Thursday for MEZ014-021-022-
026>028.
NH...Flood Watch until 4 AM EST Thursday for NHZ002>004.
Wind Advisory until 3 PM EST Thursday for NHZ001>015.
MARINE...Storm Warning until 3 AM EST Thursday for ANZ150>152.
Gale Warning until noon EST Thursday for ANZ153-154.
&&
$$
Cannon
Area Forecast Discussion
National Weather Service Topeka KS
516 PM CST Wed Feb 28 2024
.KEY MESSAGES...
- Red Flag Warning issued area-wide Thursday with dry and breezy
conditions
- Warming back up Thursday through the weekend
- Fire weather still a concern this weekend and potentially into
early next week
&&
.DISCUSSION...
Issued at 251 PM CST Wed Feb 28 2024
Upper trough axis has been shifting east of the area this afternoon
with northwesterly flow over the area. A small upper low continues
to move out of the Baja California region. Sfc high pressure
overhead has kept clear skies today and plentiful sunshine has
melted all of last evening`s snowfall per visible satellite
imagery. Despite the insolation, temperatures have been slower to
warm today so have lowered highs into the 30s with perhaps the
southern and western edges of the CWA being able to reach 40.
Main focus is on the fire weather risk Thursday. The aforementioned
upper low is progged to move east-northeast through the southern and
central Plains as an open wave, which should bring some mid to high
cloud cover northward through the afternoon and evening. This may
temper highs to some extent in southern locations, but not likely
enough to limit the fire danger concern. A lee sfc trough develops
and tightens the pressure gradient, and forecast soundings indicate
mixing up to 875 to 850mb with very dry air just above the mixed
layer. This points to a scenario with warmer and drier air mixing to
the surface, leading to greater confidence in slower moisture
return. Have continued to utilize the HRRR/RAP and NBM 10th
percentile for Tds, which gives RH on the low end of guidance.
Additionally, the mixing and pressure gradient will result in
increasing winds overnight through the morning, remaining gusty
through the day and slowly diminishing Thursday night. (See fire wx
discussion for additional info.)
As lift increases with the passing shortwave, short-term models are
starting to key in on some light QPF along and southeast of the KS
Turnpike. Soundings show a very brief period where saturation may
occur to the surface, although the 15Z RAP is not as robust, as it
is more limited in area. Decided to add some slight chance PoPs in
this area, but still only 15-20%. If any rain does fall, it wouldn`t
be enough to amount to much if anything.
Upper flow transitions to zonal late this week and eventually
southwesterly as the next trough deepens in the western CONUS.
Differences remain in the speed and depth of that trough as it
advances east, and therefore the evolution of smaller scale features
as the sfc low impacts the region. Chances for thunderstorms still
look low but not zero with a narrow window of opportunity in eastern
KS. The bigger concern will be fire weather as southerly winds pick
up and a dryline sets up (see fire discussion below).
While not quite as warm as this weekend, temperatures to remain
above normal into the next work week with a dry pattern, keeping
some potential for elevated fire danger into next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 516 PM CST Wed Feb 28 2024
VFR TAFs will continue through the period at all sites with
clear skies expected overnight and into the morning hours of
Thursday. Winds overnight will be light and veering back to the
south, staying under 10 mph. As the overnight radiation
inversion breaks around 9 AM Thursday morning, winds will begin
to increase out of the south to south-southwest for the
remainder of the period as high clouds filter in from the south.
Winds sustained between 15-20 mph can be expected with gusts up
to 30 mph during the afternoon hours. These will begin to
weaken shortly after sunset as the boundary layer begins to
decouple.
&&
.FIRE WEATHER...
Issued at 252 PM CST Wed Feb 28 2024
Dangerous fire weather conditions are anticipated tomorrow as
moisture return is slow to work into the region, leading to minimum
RH forecast in the 13-20 percent range in the afternoon.
Additionally, SSW winds are expected to strengthen to 15-25mph
sustained with gusts 25-40mph, strongest in north central KS.
Collaboration with fire partners has indicated that fuels are ripe
for fire spread. As such, the entire area is under a Red Flag
Warning for Thursday.
While Friday looks to bring some reprieve from fire danger concerns,
the weekend brings warming temperatures with Sunday being another
day with strong southerly winds and dry conditions. We`ll need to
monitor how far east the dryline makes it in order to discern how
far east the worst conditions will be. However, west of the dryline
RH looks to drop to less than 20% with southerly winds sustained 25-
30mph with gusts 30-45mph. Additionally, a cold front is forecast to
move through the area Sunday evening/night with discrepancies on
timing between models. In any case, this would bring a wind shift to
the northwest which would exacerbate problems from any fires that
get going.
&&
.CLIMATE...
Issued at 336 AM CST Wed Feb 28 2024
Record Highs:
March 2
Record Forecast
Topeka 84 in 2022 77
Concordia 81 in 2022 72
March 3
Record Forecast
Topeka 80 in 1910 81
Concordia 79 in 1946 78
Record Warm Lows:
March 3
Record Forecast
Topeka 52 in 1992 55
Concordia 50 in 1983 52
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM to 8 PM CST Thursday for KSZ008-
KSZ009-KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-
KSZ026-KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-
KSZ055-KSZ056-KSZ058-KSZ059.
&&
$$
DISCUSSION...Picha
AVIATION...Griesemer
FIRE WEATHER...Picha
CLIMATE...Flanagan