Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 290900
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EST Tue Nov 29 2016
A warm front will lift through the area today. An area of low
pressure will move across the area Wednesday with a cold frontal
passage Wednesday night. High pressure will return to the region
Friday and Saturday. Low pressure will approach the region Sunday.
.NEAR TERM /TODAY/...
As of 3am, vertically stacked cold core low with a 981mb surface low
is over junction of ND, SD, and MN. A shortwave trough axis is
apparent in water vapor imagery over MI. An associated cold front is
over the TN valley and extends SW to Houston. A swath of rain
continues to move NE from AL, though most of the moisture is being
squeezed out over the SErn states.
One brief round of rain has moved across the LWX CWA with the second
round being much more substantial and taking through most of today
to cross the area. QPF generally a quarter to half an inch through
tonight. Gusty winds up to 40 mph possible with showers particularly
over SErn portions of the CWA where convective activity is most
robust. Maxima upper 50s north and mid 60s south. 60F dewpoints lift
into southern portions of the area, a rarity for late November.
Fog is expected to develop tonight especially east of the Blue Ridge
where rain clears near or after sunset. Minima generally less than
10 degrees below the maxima with continued south winds.
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
A digging long wave trough/jet stream over the intermountain west
will keep the low centered over MN through tonight and keep the SErn
CONUS cold front essentially in place. It will take until Wednesday
night for the longwave trough axis to move across the OH valley for
the cold front to push through the Mid-Atlantic.
Rain associated with the second round/long wave trough breaks out
late tonight as convergence spreads in from the OH valley. Weak
instability may allow isolated thunderstorms east of I-95 Wednesday
Gusty west wind up to 30 mph Thursday behind the cold front with
little upslope snow. Maxima mid to upper 50s in dry air advection.
.LONG TERM /FRIDAY THROUGH MONDAY/...
High pressure over the area Friday and Saturday. Highs both days
in the lower 50s east of the mountains...mid to upper 40s west
except colder in the Highlands. Lows both night close to freezing.
Sunday...models are diverging on the timing of the short wave
that could bring the region some more rain. Euro is the faster of
the two..bringing extensive moisture into the Mid Atlantic Sunday
afternoon ahead of a warm front draped over the Gulf states. Rain
showers would be the predominant p-type...although this could mix
with snow at elevation above 2000 feet.
Short wave to approach and move through the region Monday. It is
again possible that rain could mix with snow Sunday night as
temperatures drop close to freezing. This would revert to all rain
Monday..with precipitation chances likely ending by the end of the
day as the trough moves offshore.
.AVIATION /TODAY THROUGH SATURDAY/...
MVFR conds generally today as rain overspreads the DC metros with
increasing south winds. IFR cigs possible by this evening. Fog
likely overnight between two rain events, the second beginning late
tonight. Showers with isolated thunder east of I-95 Wednesday. Cold
front crosses Wednesday night with 25 kt peak west gusts Thursday.
VFR conditions expected Friday and Saturday.
South winds increase today as rain overspreads the area. Gusty
showers and strong winds mainly this afternoon warrant gale warning
for central and southern MD waters today. SCA conditions at least
through Thursday with a cold front crossing Wednesday night. Strong
south winds ahead may mix down Wednesday and warrant another Gale.
SCA may be needed for portions of the waters Friday as high
pressure builds into the waters. No problems expected Saturday.
Water levels will continue to rise on southerly flow. Minor
coastal flooding will be possible at Annapolis at times of high
tide (5:28 pm).
MD...Wind Advisory until 1 PM EST this afternoon for MDZ501.
VA...Wind Advisory until 1 PM EST this afternoon for VAZ025>027-029-
WV...Wind Advisory until 1 PM EST this afternoon for WVZ055-501>503-
MARINE...Small Craft Advisory until 6 AM EST early this morning for
Small Craft Advisory from 6 PM this evening to 6 AM EST
Wednesday for ANZ532>534-537-540>543.
Gale Warning from 6 AM this morning to 6 PM EST this evening
Small Craft Advisory until 6 AM EST Wednesday for ANZ531-536-
Small Craft Advisory until 6 PM EST this evening for ANZ530-