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FXUS61 KLWX 221502

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1002 AM EST Wed Feb 22 2017

A weak disturbance will cross the area today. High pressure will
remain over the Atlantic tonight through Friday. A cold front 
will pass through the area on Saturday. High pressure builds 
over the area during the early part of next week.


Surface high pressure has moved off the coast and it will remain
over the western Atlantic through tonight. A cutoff low in the
southern stream of the jet will continue to drop well to our
south today while northern stream energy moves off to our east. 

A few showers have developed over central Virginia and southern
Maryland this morning due to moisture from the southern stream
system. Elsewhere...dry conditions persist with just high and
mid-level clouds. As the southern stream system drops farther
south...showers will dissipate across most areas late this
morning. High and mid-level clouds will gradually decrease this
afternoon from north o south as the northern stream energy 
moves away. A southerly flow around the high along with some
afternoon sunshine will allow for unusually mild conditions for
this time of year. Temperature forecast is a bit tricky due to
exact timing of clearing...but even with a little sunshine max
temps should reach well into the 60s for most places. Did keep
forecast a bit cooler across our extreme southwest zones where
clouds may hang on a bit longer. 

Warm and moist air will continue to advect into the Mid- 
Atlantic region tonight. Low clouds and fog are expected by 
Thursday morning as dewpts remain elevated. Temps will only drop
into the U40s/L50s tonight...which is close to our climo for max
temps this time of year. 


The southern stream system will persist off the SE coast 
Thursday and Thursday night. Due to the southwesterly flow 
aloft...moisture advection and above normal temperatures will 
persist. A cold front will approach the Mid-Atlantic region 
Thursday and showers are possible Thursday afternoon mainly west
of the metros. Showers may move east across the metros Thursday
evening however the cold front will stay north of the region 
and amts will be light. A mix of sun and clouds will allow 
temperatures to reach the mid 70s and 60s near the waters.

Showers move east and dissipate across the region by Friday morning. 
Dry conditions expected Friday. Another warm day expected with 
temperatures reaching the mid to upper 70s. A strong system will 
approach the Mid-Atlantic region Friday night and showers are 
possible as southerly flow increases.


Cdfnt will move through the fcst area Sat afternoon with 
showers and possible t-storms. Simulated satellite imagery from 
both ECMWF and GFS shows strong convection over Ohio Fri night 
weakening as it approaches the Appalachians Sat morning with a 
narrow frontal rain band developing east of the Blue Ridge Sat 
afternoon. The simulated imagery shows convection deep enough to
produce lightning north of I-70 with shallow convection south 
of there. H85 winds peak between 35-45kt and CAPE values rise 
between 100-350 J/kg. A few severe t-storms may develop along 
the PA border. Cdfnt clears the Chesapeake Bay by 00Z Sun. 

High pressure then builds over the area Sunday night and early
Mon. Developing waa pattern on Monday will result in increasing
chances of precip Mon afternoon. Warm and unsettled conditions
will then prevail through Wed before a cdfnt clears the area by
next Thu. Guidance also suggest another chance at reaching 80F 
on Wed with h85 temps as high as 17.5C and 1000-850 mb 
thicknesses of near 1400 meters under a strong SW flow.


VFR conditions expected today as light southerly winds persist.
Low clouds and/or fog are expected Thursday morning. MVFR/IFR 
restrictions are expected at all terminals. Clouds will 
dissipate by mid morning Thursday and VFR conditions are 
expected. S winds continue through Friday night. 

Cdfnt to move through terminals around 18Z Sat with showers and
possible t-storms with gusty winds.


High pressure will remain off the coast through Thursday night.
A southerly flow is expected during this time...but wind speeds
should remain below SCA criteria. Dry conditions expected for
Friday before a cold front moves across the Mid-Atlantic on 

Strong cold front will move through the waters Sat afternoon
with showers and possible t-storms some of which could produce
strong winds and require SMWs particularly across northern
portions of the waters.


Warmest Februaries

   DCA           BWI           IAD
1. 46.9 (1976)   44.0 (1976)   42.1 (1990)
2. 45.2 (1990)   43.9 (1949)   41.1 (1976)
3. 44.7 (1997)   43.3 (1890)   41.0 (1998)
4. 44.3 (2012)   42.7 (1932)   40.9 (2012)
5. 43.9 (1949)   42.6 (1909)   40.5 (1997)

Feb 2017 (through the 21st)

DCA: 45.1  BWI: 41.6   IAD: 42.1

Temperature records for the Washington DC area have been kept at 
Ronald Reagan National Airport (DCA) since 1941. Additional 
temperature records for the Washington DC area date back to 1872.

Temperature records for the Baltimore MD area have been kept at 
Baltimore-Washington International Thurgood Marshall Airport (BWI) 
since 1950. Additional temperature records for the Baltimore MD 
area date back to 1872.

Temperature records in the Dulles VA area have been kept at 
Washington Dulles International Airport (IAD) since 1962.

All records are considered preliminary until reviewed by the 
National Center for Environmental Information (NCEI).





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