Area Forecast Discussion
Issued by NWS Sterling, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
000
FXUS61 KLWX 290801
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
401 AM EDT FRI APR 29 2016

.SYNOPSIS...
A COLD FRONT WILL REMAIN STALLED TO THE SOUTH TODAY. ANOTHER WEAK
WAVE OF LOW PRESSURE WILL RIDE ALONG THE BOUNDARY. THE BOUNDARY
WILL DROP SOUTH SATURDAY...THEN LOW PRESSURE MOVES THROUGH THE
MID-ATLANTIC SUNDAY AND MONDAY. ANOTHER FRONT WILL MOVE THROUGH
LATER NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
A RELATIVE LULL IN ACTIVITY ACROSS THE AREA THIS MORNING...WITH ONLY
A FEW SHOWERS EMBEDDED WITHIN THE DZ AND LIGHT FOG. WEDGE OF HIGH
PRESSURE EVIDENT EAST OF THE MTNS IN VA...WITH MAIN FRONT STILL
DRAPED ACROSS NC. SUBTLE SHORTWAVE TROUGH OVER WVA MAY SPARK A FEW
SHOWERS THIS MORNING ACROSS THE NORTHERN HALF OF THE
AREA...OTHERWISE PRECIP SHOULD LARGELY BE DZ.

GUIDANCE HINTING THAT CLOUDS MAY ERODE SOME BY THIS AFTERNOON ACROSS
SOUTHWESTERN PORTIONS OF THE AREA. PERHAPS NOT CLEARING...BUT AT
LEAST LIFTING. ELSEWHERE EXPECT LOW CLOUDS TO HOLD FIRM. SHOULD BE
ENOUGH DRYING TO CUT BACK ON DZ/FOG THOUGH. THIS COULD LEAD TO A
GRADIENT IN TEMPERATURES...WITH COOLEST TO THE NE. HAVE SHADED A
LITTLE BELOW MODEL BLEND.

VORT MAX CURRENTLY OVER LAKE MICHIGAN WILL PASS TO THE NORTH LATE
THIS AFTERNOON. THIS WILL BRING A RENEWED CHANCE OF LIGHT SHOWERS
MOVING FROM NW TO SE ACROSS THE REGION. HAVE KEPT POPS AT CHANCE
GIVEN EXPECTED SCATTERED/LIGHT NATURE. THIS WILL ALSO SERVE TO GIVE
THE FRONTAL ZONE A NUDGE TO THE SOUTH AND DRY OUT THE
ATMOSPHERE...EXCEPT AT THE LOW LEVELS. WITH A CONTINUED OVERRUNNING
FLOW...HAVE KEPT PATCHY DZ WORDING IN THE FORECAST LATE TONIGHT.
LIGHT FOG POSSIBLE ONCE AGAIN TOO. SAME TREND...ONLY SMALL DROP IN
TEMPS OVERNIGHT.


&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE TREND FOR THE WEEKEND CONTINUES TO BE LESS DRY. NOT A TOTAL
WASHOUT...BUT PROLONGED BREAKS WILL BE SPARSE ONCE ISENTROPIC LIFT
BEGINS AHEAD OF LOW PRESSURE OVER THE PLAINS. RAIN COULD ARRIVE IN
THE MOUNTAINS SATURDAY MORNING...AND AT LEAST A CHANCE OF IT
SPREADING EAST DURING THE AFTERNOON. STILL SOME TIMING DIFFERENCES.
BUT BROUGHT POPS TO CATEGORICAL SATURDAY NIGHT AND WORDED AS
RAIN...LOOKS LIKE A GOOD SLUG OF MOISTURE...AND PERHAPS BE MODERATE
AT TIMES. TRENDED MAX T ON SATURDAY DOWN A LITTLE.

SFC LOW AND OPENING UPPER WAVE WILL BE APPROACHING THE OHIO VALLEY
SUNDAY INTO SUNDAY NIGHT. CONTINUED LIFT AND MOISTURE ADVECTION WILL
MEAN HIGH CHANCES OF SHOWERS CONTINUING. BIGGEST UNCERTAINTY IS WHAT
HAPPENS TO WEDGE FRONT ON SUNDAY. PLAYING TOWARD MODEL BIASES...ONCE
AGAIN WENT BELOW THE MODEL BLEND. HOWEVER...CENTRAL VA MAY BE ABLE
TO BREAK INTO THE WARM SECTOR. AND LAPSE RATES ALOFT WILL BE FAIRLY
STEEP ACROSS THE ENTIRE AREA. HAVE SLIGHT CHANCE OF THUNDER NORTH
AND CHANCE SOUTH. WITH MODERATE DEEP LAYER SHEAR...THERE COULD BE
SOME STRONGER STORMS TOWARD CENTRAL VA...AND THIS AREA IS INCLUDED
IN SPC DAY 3 MARGINAL RISK. MODEL CONSENSUS ATTM IS FOR LOW TO BE
PULLING AWAY LATE SUNDAY NIGHT.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
LATEST GUIDANCE SUPPORTS THE IDEA OF THE LOW PRESSURE DEPARTING
THE AREA FASTER ON MONDAY...THOUGH PASSING TROUGH AND NORTHEAST
FLOW MAY KEEP A FEW SHOWERS GOING ACROSS THE REGION. THE FLOW MAY
TURN NORTHWEST IN THE AFTERNOON WHICH COULD ALLOW CLOUDS TO BREAK
AND SOME SUN TO REACH THE GROUND...AND ALLOW TEMPS TO NEAR 70.
GUIDANCE MOSTLY AGREES ON A DRIER TREND MONDAY NIGHT BUT TUESDAY
ONWARD IS STILL QUESTIONABLE WITH THE EC STILL SHOWING A WAVE
MOVING NORTHEAST FROM THE GULF...WHILE THE GFS IS MUCH SLOWER
BRINGING A WAVE UP. BOTH MODELS DO SHOW THE WAVE OFF THE SOUTHEAST
COAST WEDNESDAY BUT ARE SHUNTED EAST OF THE PREVIOUS EC
RUNS...KEEPING US MOSTLY DRY. GFS AND EC BOTH HAVE ANOTHER FRONT
SLIDE IN FROM THE NORTHWEST ON THURSDAY WITH MUCH COOLER AIR
BEHIND IT. GFS IS FAIRLY DRY WHILE EC GENERATES A FAIR AMOUNT OF
SHOWERS. OVERALL IT WILL BE A COOLER THAN NORMAL WEEK WITH HIGHS
MOSTLY NEAR OR BELOW 70.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
WIDESPREAD IFR/LIFR CONDITIONS THIS MORNING. THESE SHOULD CONTINUE
THROUGH DAYBREAK. MOST GUIDANCE HAS CIGS LIFTING TO MVFR BY THIS
AFTERNOON...BUT LOW CONFIDENCE ON HOW HIGH. COULD BE A FEW SHOWERS
EARLY THIS MORNING AND AGAIN LATE THIS AFTERNOON...BUT COVERAGE WILL
PRECLUDE TAF MENTION FOR NOW. OTHERWISE EXPECT PREDOMINANTLY DZ.

CONDITIONS WILL DETERIORATE AGAIN TONIGHT WITH WIDESPREAD IFR
EXPECTED WITH LOW CIGS...DZ...AND FOG. SHOULD BE SOME IMPROVEMENT ON
SATURDAY WITH PERHAPS VFR DURING THE MIDDAY. BROAD AREA OF
RAIN...PERHAPS MODERATE...WILL MOVE ACROSS THE AREA SATURDAY NIGHT
WITH SUB-VFR CONDITIONS LIKELY. SHOWERS CONTINUE SUNDAY INTO SUNDAY
NIGHT WITH THUNDER POSSIBLE...ESPECIALLY CHO. TEMPORAL RESOLUTION OF
CIGS/VSBYS BECOMES LESS CERTAIN DURING THIS TIME.

CIGS AND VIS LIKELY TO IMPROVE GRADUALLY MONDAY WITH VFR PROBABLE
BY TUESDAY.

&&

.MARINE...
ONSHORE FLOW WILL CONTINUE THROUGH SATURDAY. GENERALLY EXPECTING 5-
10 KT WITH OCCASIONAL INCREASES TO 15 KT. LIGHT FOG AND DZ WILL
CONTINUE AT TIMES. NEXT ROUND OF RAIN AND ASSOCIATED LLJ IS A LITTLE
QUICKER NOW AND SCA CONDITIONS MAY BE REACHED AS EARLY AS SATURDAY
NIGHT. THIS POSSIBILITY WILL REMAIN SUNDAY INTO SUNDAY
NIGHT...ALTHOUGH PERHAPS NOT CONTINUOUSLY. THUNDERSTORMS WILL ALSO
BE POSSIBLE SUNDAY AFTERNOON AND EVENING. SCA CONDITIONS REMAIN
POSSIBLE WITH LOW PRESSURE PASSING ON MONDAY.

&&

.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES HAVE CONTINUED TO DECLINE OVERNIGHT...AND RIGHT
NOW WE DO NOT EXPECT ANY FLOODING WITH THE MORNING CYCLE. WILL
NEED TO CONTINUE WATCHING ANOMALIES AS WITH THE CONTINUED
NORTHEAST FLOW...WATER LEVELS MAY RE-BUILD IN THE BAY AND POTOMAC.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...RCM
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...RCM
AVIATION...ADS/RCM
MARINE...ADS/RCM
TIDES/COASTAL FLOODING...RCM



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.