Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/28/22
Area Forecast Discussion
National Weather Service Gray ME
1052 PM EST Sun Feb 27 2022
.SYNOPSIS...
Arctic cold front exits to the S and E later this evening. It
will be cold and blustery tonight with wind chills falling below
zero. Wind chills will drop to 20 below zero or colder in the
mountains tonight. High pressure will dominate the weather
tomorrow before a quick hitting clipper system brings some light
snow to the region Tuesday night.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
1045 PM...arctic front and SHSN have cleared the CWA at this
point with T/Tds falling quickly on gusty NW winds. May see a
brief bout of upslope SHSN, once the dry air advection slows
during the overnight. otherwise gusty winds should settle by
midnight.
735 PM...Line of snow squalls mostly weakening as it exits the
area, ans may see a few more run of the SHSN this evening, but
these should end well before midnight as well, with the
exception of some upslope SHSN in the mountains which will
until after midnight, but should end before daybreak Monday.
Winds stay gusty through about 02-03Z, but they will settle down
a bit although still remain strong enough to produce wind
chill, especially with rapidly falling temps. Low bottom out
from -5 to zero in the N, to around 10 above in srn NH and
coastal ME.
Previously...Current radar shows areas of snow showers in the
mountains with some returns downstream over the coastal plain of
Maine. Area webcams and surface obs confirm snow showers
activity in the mountains while downstream returns are likely
still just virga. Farther upstream radar shows a well defined
line of snow squalls across Upstate NY into NW Vermont.
Observations and LSRs from BTV show this line of squalls has
produced winds in excess of 40 MPH and visibility reduced to 1/4
mile.
CAMs continue to paint a robust area with snow squall parameters of
3 to 5 across the northern two thirds of the area with parameter
values dropping towards southern New Hampshire and the Maine coast,
but still high enough to bring potential for snow squalls to these
areas. Latest RAP analysis shows a slight downward trend in
instability with the steepest low level lapse rates not making
their way into southern New Hampshire. However, the HRRR and
other CAMs remain steadfast in holding a line of heavy snow
showers and squalls together as the Arctic front presses
southeast through the area this evening.
This line of heavy snow showers and squalls is expected to
reach NW New Hampshire just after 4 PM and will be pushing south
of the foothills between 5 and 6 PM and it is here where the
best opportunity will be for sudden bursts of heavy snow, strong
winds and visibility that could drop to less than 1/4 mile.
Despite waning snow squall ingredients this line will approach
the Maine coastline around 7 PM and the NH/MA border around 8
PM. Current temperatures along and south of the foothills are in
the mid to upper 30s with temperatures expected to drop into
the 20s with the frontal passage adding the concern for wet and
slushy roads to freeze quickly this evening.
Snow shower and squall activity will diminish after 8 to 9 PM
with gusty northwest winds in the wake of the front.
Temperatures will drop well below zero across the north and with
gusty NW winds wind chills will drop below 20 below and have
continued the Wind Chill Advisory for tonight into Monday
morning. South of the mountains temperatures will drop into the
single digits to near 10 degrees with wind chills below zero
into Monday morning.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Monday will be cold and blustery as high pressure builds in from
the west. Expect mostly sunny skies with NW winds gusting up to
30 MPH through mid day. Highs will be restricted to the single
digits across the far north with mid to low 20s across the
south. Winds will start to relax late Monday as high pressure
moves near overhead. With high pressure cresting over the region
Monday night radiational cooling will allow for temperatures to
drop well below zero across the north and into the single digits
across the south.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Overview: Near to below normal for much of the extended trending
above normal by the weekend. Main trof axis overhead to east of the
area will keep any precip rather light until larger trof digs to the
west by the weekend.
Impacts: Light snow accumulations are probable Tue evening/early Wed
morning and may impact the evening and morning commutes.
Forecast Details: Tue the clipper system approaches the area from
the west. The primary forcing mechanism will be WAA at H8...fairly
broad and uniform across the forecast area. This should translate to
fairly uniform light snowfall amounts across the area as well. The
exception will be around Casco Bay and points north. Lingering cold
mid level temps will support ocean effect snow as flow returns. This
may both increase the intensity and duration of snowfall for these
areas and so I currently am forecasting higher amounts approaching
Penobscot Bay.
Forecast for late Wed into Thu is a little trickier. Model guidance
suggestive of a follow up wave producing some lights snows as it
slides south of the forecast area. 27.12z GFS shows more of a cold
frontal passage...while its own ensemble has around half the members
producing light snow. To me this suggests that there are still a
couple scenarios on the table...and I will keep PoP at chance given
the uncertainty.
Deeper southwest flow develops across CONUS Fri and starts to
edge into the Northeast by Sat. I expect gradually warming temps
thru the weekend. Deeper moisture and stronger warm frontal
forcing will also mean the threat for a more robust QPF event
will become more likely by Sun.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
Short Term...A arctic boundary will continue to push south late this
afternoon bringing the threat for quick hitting snow showers /
squalls. This could bring a rapid onset of IFR/LIFR conditions
due to snow for most TAF terminals late afternoon/evening. MVFR
and -SHSN may linger at KHIE through the first part of tonight
with VFR expected for remaining terminals in the wake of the
front tonight. Westerly winds will shift out of the NW tonight
with gusts around 25 kts. VFR is expected monday into Monday
night as high pressure builds in.
Long Term...VFR early Tue will give way to areas of IFR or lower
in SN. May see some local IFR conditions early in the day
between PWM and RKD as ocean effect SHSN move onshore. VFR
returns Wed in offshore flow. Another round of SN and IFR or
lower conditions is possible Thu but is lower confidence than
the Tue event.
&&
.MARINE...
Short Term...Arctic front crosses the waters this evening with
westerly winds shifting out of the NW behind the front and Gale
conditions expected into Monday morning. Arctic air pouring
over the waters will also bring moderate freezing spray late
tonight into Monday. High pressure builds in Monday from the
west with SCA conditions lingering into Monday evening before
subsiding Monday night.
Long Term...Marginal SCA conditions possible ahead of
approaching clipper system in southerly flow. This will shift to
westerly behind the clipper and may continue around marginal SCA
conditions into Wed morning. CAA across the waters Thu may bring
another round of SCA conditions.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Wind Chill Advisory from 4 AM to 10 AM EST Monday for
MEZ007>009.
NH...Wind Chill Advisory from 4 AM to 10 AM EST Monday for NHZ001-
002.
MARINE...Freezing Spray Advisory until 1 PM EST Monday for ANZ150>154.
Gale Warning until 10 AM EST Monday for ANZ150>154.
&&
$$
SYNOPSIS...
NEAR TERM...Cempa/Schroeter
SHORT TERM...Schroeter
LONG TERM...Legro
AVIATION...Legro/Schroeter
MARINE...Legro/Schroeter
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
849 PM CST Sun Feb 27 2022
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
As of 0200Z, clouds were clearing in the northwest with the back
edge of the stratus deck roughly along the highway 82 corridor.
Behind the clouds, winds will diminish and radiational cooling
will allow temperatures to fall below freezing in the north and
west. Temperatures in portions of the Delta area will drop to near
the dewpoints and this will lead to some fog. With temperatures
below freezing, some freezing fog could result in mostly minor ice
accretion on elevated surfaces. Conditions will continue to be
monitored overnight for any potential freezing fog warning
possibility. Temperatures warm quickly after dawn with the help
of full sun. /86/
Prior discussion below:
Tonight & Monday...
Tonight: As the SW-NE oriented trough axis & strong isentropic
subsidence moves in this evening, clouds will quickly clear from NW-
SE, as they are currently are in the NW Delta. This will help clear
out of NW of the Natchez Trace by midnight & out of the region by
daybreak. As shortwave ridge axis builds in through daybreak, sfc
ridging will help temps fall below freezing for areas along & NW of
the Natchez Trace & into the mid-upper 30s to the SE into the I-59
corridor. There are indications for some potential for patchy fog
development, right around the MS River, due to good crossover
potential. Light gradient N-NE wind may be able to limit that
potential somewhat. However, low-end HREF probs, HRRR & NAM show
indications of some better potential, so for now will introduce fog
for areas along & N-NW of a line from Winnsboro to Vicksburg to
Yazoo City to Greenwood. Due to temps falling below freezing, some
of this could be patchy freezing fog. With more expected mist rather
than dense fog & some gradient wind that could limit coverage/dense
fog potential, will hold off any mention in the HWO. If trends
continue in the direction of dense fog, future mention in the HWO &
freezing fog advisory may be needed.
Monday: Shortwave ridge axis will build through the area, with some
increase in thermal warmth. With deep, dry air profiles (i.e. PWs
only around a quarter inch) & efficient mixing & clear skies, highs
will moderate near climo into the low-mid 60s. /DC/
Tuesday through next weekend...
Overnight tomorrow night...temps warm slightly...remaining above
freezing through the early morning hours. Overall, the weather
quiets down a bit with weakly northwesterly flow aloft over the
region. Temperatures moderate, with highs in the 60s Tuesday,
starting a warming trend that will culminate in upper 70s/near 80 by
Friday. Overnight lows running tandem will start in the 30s...to
lower 50s by Friday. High pressure ridging over the Gulf States and
the Southeast keeps the weather quiet and the flow pretty light with
some variability over the region through the end of the week. By
Friday, an upper wave drops in over the west coast and into the
desert SW, resulting in a pattern shift and a 500 mb ridge building
in over the Mississippi River Valley, at least briefly. That same
wave develops a surface low that moves into the Southern Plains for
Saturday. Given the WAA shown in the ECMWF in the mid levels and
the stronger southerly surface winds Saturday, temperatures may not
be warm enough for the first part of the weekend. Also, the NBM
winds seem far too low for Day 8...but that is also highly dependent
on the evolution of the next storm system expected to bring
precip/storms for the weekend. /HJS/
&&
.AVIATION...
00Z TAF discussion:
MVFR to IFR ceilings persist this evening and will be slow to
improve through the remainder of the evening. However, some
improvement to VFR will be possible through the overnight hours
and by daybreak all sites should be VFR. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 31 63 35 68 / 0 0 0 0
Meridian 34 63 35 69 / 1 0 0 0
Vicksburg 30 62 33 66 / 0 0 0 0
Hattiesburg 37 65 35 70 / 0 0 0 0
Natchez 31 62 34 67 / 0 0 0 0
Greenville 30 60 35 65 / 0 0 0 0
Greenwood 30 61 35 65 / 0 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
LP