Mesoscale Discussion 0097
NWS Storm Prediction Center Norman OK
0325 AM CST Sat Jan 29 2022

Areas affected...portions of the Delmarva Peninsula northeastward to
coastal/offshore Maine

Concerning...Heavy snow 

Valid 290925Z - 291530Z

SUMMARY...Heavy snowfall -- with widespread rates in excess of an
inch per hour and increasing locally to 2" to 3" per hour over the
next few hours -- is expected through mid morning from the
Mid-Atlantic region to southeastern New England.

DISCUSSION...Latest radar loop shows a large area of moderate to
heavy snowfall from southeastern Virginia to eastern Massachusetts. 
The heaviest snow is indicated at this time from the southern
Delaware/far southeastern Maryland vicinity north-northeastward
across coastal southeastern New Jersey to portions of western and
central Long Island.

While models indicate the center of the surface low to be well to
the east, a cyclonic circulation evident in radar imagery is
indicated just east of the southern tip of the Delmarva Peninsula. 
This circulation appears to be associated with a mid-level vorticity
maximum.  As this vort max, and associated surface low, shift slowly
north-northeastward with time, the band of heaviest snowfall is
expected to remain aligned across the same general area, while
expanding northeastward, and eventually approaching coastal portions
of Maine through 29/15Z.  This increase/expansion of the heavy snow
zone will occur as warm advection within a middle tropospheric layer
centered around 700mb strengthens over the next 3 to 6 hours.

In addition to the heavy snowfall, an increase in surface winds is
expected, in response to the gradual deepening of the surface low.  
This will contribute to some further reductions in visibility due to
blowing snow -- even in areas outside of the heaviest snow bands, as
winds approach or exceed blizzard criteria.

..Goss.. 01/29/2022

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CAR...GYX...BOX...OKX...ALY...PHI...AKQ...

LAT...LON   37977546 38327594 39107583 40377478 41567315 42647181
            43826972 44516753 44406664 43416664 42147007 41427054
            40697162 39837308 38407438 37977546 

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
1255 AM CST Sat Jan 29 2022

Valid 311200Z - 011200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
A strong storm or two will be possible near the Lower or Middle
Texas Coast Monday morning into early afternoon. However, overall
severe thunderstorm potential appears low at this time.

...Lower/Middle Texas Coast Vicinity...

A mid/upper level low and attendant trough will be positioned over
western/central TX Monday morning. This system should move over the
western Gulf of Mexico by Monday evening and into the overnight
hours. At the surface, a weak low and cold front will shift east
from the Edwards Plateau to the Lower/Middle TX Coast by late
afternoon. Ahead of the low, southerly low-level flow will allow
surface dewpoints to climb into the upper 50s to low 60s F. Midlevel
lapse rates around 7-7.5 C/km are indicated in forecast soundings,
aiding in mainly elevated instability of 200-400 J/kg MUCAPE.
Deep-layer flow will remain somewhat modest, but backed low-level
winds in the vicinity of the coast will allow for effective shear
magnitudes around 20-30 kt. Showers and isolated thunderstorms will
likely be ongoing at the start of the forecast period. Given the
timing of the upper trough and surface cold front, a couple strong
thunderstorms may be possible during the morning/early afternoon.
Small hail and gusty winds may accompany the strongest cells.
However, modest shear and weak instability will limit overall severe
potential and severe probabilities will not be introduced at this
time.

..Leitman.. 01/29/2022

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0243 AM CST Sat Jan 29 2022

Valid 011200Z - 061200Z

...DISCUSSION...
An upper trough is forecast to deepen across the western U.S. on Day
4/Tue and eject into the Plains on Day 5/Wed. Strong deep-layer
southwesterly flow ahead of the upper trough in southerly low-level
flow across the Gulf Coast region will allow for moderate moisture
return from the TX coast through the Lower MS Valley and northern
Gulf Coast vicinity early in the period. By Day 6/Thu, the upper
trough is forecast to lift northeast across the Midwest. The
strongest forcing for ascent will remain north of the southeastern
U.S. However, a cold front will develop eastward across the
Mid-South and northern Gulf Coast states, and widespread showers and
thunderstorms are likely. Poor lapse rates and weak diurnal heating
will limit destabilization despite 60s F surface dewpoints.
Nevertheless, moderate to strong deep-layer southwesterly flow in
the presence of weak instability may be sufficient for a narrow
corridor of marginal severe thunderstorm potential from far
southeast LA/southern MS/AL and the western FL Panhandle on
Thursday. At this time, severe potential appears too
uncertain/limited to include 15-percent probabilities.

The upper trough will continue to shift east/northeast on Day 7/Fri
while a closed low develops over the southwestern states/northern
Mexico. The southwestern upper low/shortwave trough will migrate
east into TX at the end of the period. However, the cold front from
Day 6/7-Thu/Fri and strong surface high pressure across much of the
U.S. on Day 8/Sat will preclude thunderstorm potential.

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0117 AM CST Sat Jan 29 2022

Valid 291200Z - 301200Z

...Synopsis...
Predominantly northwesterly mid-level flow will persist across the
central U.S as an upper trough ejects into the Atlantic today. A 500
mb impulse embedded in the broader northwesterly mid-level flow will
overspread the central Plains during the afternoon hours. As a
result, a large enough span of overlapping 15 mph sustained
northwesterly surface winds and 15-20 percent RH will develop by
afternoon peak heating, warranting the maintenance of Elevated
highlights despite cooler surface temperatures. Farther south across
western Texas into central Oklahoma, 15-20 percent RH is expected
due to broad lee troughing supporting the eastward push of dry air
from the southern High Plains. Nonetheless, surface winds are
expected to remain below 15 mph on a widespread basis per latest
guidance consensus, precluding the introduction of Elevated
highlights this outlook. Should any increase in surface winds become
evident in later guidance, Elevated highlights may need to be added
in the 17Z update.

Dry and breezy northwesterly surface flow is expected across the
Florida Peninsula, behind the surface cold front. However, fuels
across the area remain poorly receptive to fire spread, hence the
withholding of fire weather highlights.

..Squitieri.. 01/29/2022

...Please see www.spc.noaa.gov/fire for graphic product...