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Area Forecast Discussion

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FXUS61 KLWX 190751
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
351 AM EDT SAT APR 19 2014

.SYNOPSIS...

LOW PRESSURE OVER GEORGIA IS DIRECTING HIGH CLOUDS INTO THE MID
ATLANTIC STATES. HIGH PRESSURE OVER THE UPPER GREAT LAKES WILL BE
WORKING INTO THE AREA THIS AFTERNOON BRINGING CLEARING SKIES. THE
HIGH WILL REMAIN IN CONTROL OF THE REGION'S WEATHER INTO MONDAY. A
COLD FRONT WILL BRING RAIN TO THE AREA TUESDAY. HIGH PRESSURE WILL
RETURN FOR THE SECOND HALF OF THE WORK WEEK.

&&

.NEAR TERM /TODAY/...

TWO SYSTEMS DUELING TO CONTROL THE WX OF THE MID ATLC - LOW PRES
ON THE FL/GA BRDR AND HIGH PRES CENTERED OVR LAKE SUPERIOR. THIS
AS CAUSED A SHARP CUTOFF RA LN JUST S OF THE CWA...W/ RA FALLING
ACROSS SERN VA. FURTHER N XTNSV HIGH CLDS XTND INTO SRN PA...BUT
THESE CLDS ARE BEING ERODED FM THE NW AS THE HIGH PUSHES INTO
OH/NWRN PA. THIS IS EXPECTED TO BECOME THE DOMINANT FEATURE IN THE
MID ATLC THIS AFTN CAUSING CLDS TO THIN/SUNSHINE TO INCRS.

HIGHS THIS AFTN IN THE M60S.

&&

.SHORT TERM /TONIGHT/...

THE SERN LOW WL MOVE OFFSHORE TNGT...BUT IS NOT XPCTD TO BE A
PLAYER IN MID ATLC WX. AGN HIGH PRES TO THE N WL BE FILTERING IN
TO THE RGN...BRINGING CLR SKIES AND GOOD RAD CONDS. ATTM MDLS ARE
FCSTG A40 BUT FEEL W/ THIS SET UP TEMPS COULD DROP LOWER AWAY FM
THE CITIES. W OF I-95 TEMPS WL FALL INTO THE U30S - IF DAYSHIFT FEELS
TEMPS COULD GO A LTL LOWER A FROST ADVSRY MAY BE NEEDED BUT AM
GOING TO ALLOW THE LATER SHIFT TO MAKE THAT DETERMINATION.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...

'TIS THE SEASON FOR CUT-OFF UPPER LOWS. WITH THE JET STREAM 
RETREATING SLOWLY TO THE NORTH BUT STILL HANGING AROUND THE 
US/CANADA BORDER...ENOUGH ENERGY EXISTS IN THE INCOMING SHORTWAVES 
FOR SOME TO 'BREAK OFF' AND HOVER FURTHER SOUTH OVER THE CONUS. THE 
FIRST ONE IN THE CURRENT FORECAST CYCLE IS THE UPPER LEVEL LOW 
SPINNING OFF THE SE ATLC COAST. THIS FEATURE WILL CONTINUE TO SPREAD 
RAIN ACROSS THE CAROLINAS INTO SUNDAY AS THE UPPER LOW SLOWLY DRIFTS 
OFF THE COAST AHEAD OF THE NEXT SHORTWAVE. HIGH PRESSURE WILL 
SQUEEZE IN BETWEEN THESE TWO SYSTEMS...CENTERED OVER NEW ENGLAND AND 
STRETCHING DOWN ACROSS THE DEEP SOUTH. THE POSITION OF THE HIGH WILL 
CONTINUE TO STREAM IN ONSHORE FLOW TO THE MID-ATLC...KEEPING THE 
TEMPS/HUMIDITY MODERATED W/ HIGHS ON SUN ONLY IN THE L/M60S. 
RELATIVELY DRY AIR FROM THE ELY FLOW WILL ALLOW TEMPS TO DROP DOWN 
INTO THE 40S FOR OVERNIGHT LOWS BUT STILL WELL ABOVE FREEZING. 

ON MONDAY...THE SHORTWAVE THAT WAS INITIALLY ASSOCIATED W/ AN UPPER 
LOW OVER THE CNTRL PLAINS WILL GET PULLED BACK INTO THE FASTER UPPER 
FLOW. BY LATE MON...THE BETTER ORGANIZED SHORTWAVE WILL BE  
STRETCHED OUT FROM THE GREAT LAKES TO THE SRN PLAINS WHILE THE MID 
ATLC RECEIVES ANOTHER DAY OF REPRIEVE FROM ACTIVE WX. THE ELY 
ONSHORE FLOW WILL DROP OFF AND WINDS WILL TURN MORE SLY...ALLOWING 
THE WRN HALF OF THE REGION TO WARM-UP INTO THE L70S WHILE THE ERN 
HALF ENDS UP A FEW DEGREES COOLER FOR DAYTIME HIGHS. MOST MED RANGE 
MEMBERS SHOWING THIS...ESPEC THE GFS. THE BIAS-CORRECTED VERSIONS OF 
BOTH THE GFS AND NAM ARE BOTH A FEW DEG WARMER OVERALL THAN THEIR 
DETERMINISTIC PARENT - SO MORE OF A BLEND WAS UTILIZED. 

A DECENT COLD AIR ADVECTION REGION WILL BE PUSHING THE SHORTWAVE 
FROM THE OHIO VLY TOWARD THE APLCNS EARLY TUE. THE SFC LOW WILL GAIN 
SOME STRENGTH ON TUE AS IT MOVES ACROSS THE ERN GREAT LAKES...BUT 
TAKE A GOOD PORTION OF THE DYNAMICS W/ IT TO THE NORTHEAST - AT 
LEAST INITIALLY. THOUGH THE NAM'S CURRENT CYCLE ENDS EARLY 
TUE...COMPARING THE APPROACH OF THE SHORTWAVE AND SFC FEATURES TO 
THE GFS AND EURO SHOWS A WEAKER FEATURE THAN EITHER LONG RANGE 
MEMBER BUT CLOSER TO THE EURO. THE 00Z GFS BRINGS A KICKER DOWN 
ACROSS THE REGION LATE TUE INTO EARLY WED...BUT JUST AFTER A BULK OF 
THE PRECIP HAS EXITED. THE 00Z EURO IS A BIT SLOWER W/ THE 
PROGRESSION AND EXIT OF THESE FEATURES...WHICH BRINGS INTO QUESTION 
THE POTENTIAL FOR CONVECTION ALONG W/ THE FRONTAL PASSAGE ON TUE 
AFTN/EVE. MODEL SOUNDINGS ONLY PAINTING A LOW/MODEST AMOUNT OF 
FAVORABLE CONVECTIVE PARAMETERS ACROSS THE SRN TIER OF THE CWA WHICH 
TAPERS OFF SUBSTANTIALLY TOWARD THE I-66 OF NRN VA. ENOUGH WARM AIR 
AND EXPECTED HIGHS IN THE L-M70S FOR THESE SRN TIER AREAS FOR AT 
LEAST A CHANCE FOR ELEVATED OR BRIEF CONVECTIVE INITIATION - SO A 
SLIGHT CHANCE OF THUNDER INTRODUCED FOR THE BRIEF FEW HRS OF TUE 
AFTN/EVE. 

A MODEST REGION OF SUBSIDENCE WILL THEN SPREAD ACROSS THE AREA ON 
WED...BRINGING GUSTY NW WINDS AND DRIER/COOLER AIR. NOT NEARLY AS 
POTENT AS THE STORM SYSTEM A WEEK AGO AT THE SAME TIME...BUT STILL 
ONLY ALLOWING TEMPS TO RISE BARELY INTO THE L60S ACROSS MUCH OF THE 
AREA W/ A BRISK 15-25MPH NW WIND. A POTENT CUT-OFF UPPER LOW OVER 
THE NRN ROCKIES WILL LOSE SOME OF ITS PUNCH AS IT SLIDES EAST OF THE 
MISS RVR LATE THIS WEEK...AS HIGH PRESSURE AGAIN GIVES THE MID ATLC 
A COUPLE MORE QUIET WX DAYS FOR THU AND FRI.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...

VFR CONDS XPCTD TDA AND TNGT.

ONSHORE WINDS WILL CONTINUE ON SUNDAY...W/ A STEADY 10-15KT BREEZE 
EXPECTED BUT THE NEXT CHANCE FOR PRECIP WILL HOLD OFF UNTIL TUE 
AFTN/EVE W/ A COLD FRONTAL PASSAGE. A CHANCE FOR A FEW TSTMS SOUTH 
OF THE DC METRO AREA TAF SITES W/ THE BOUNDARY...THEN THIS ACTIVITY 
WILL PUSH OFF THE COAST INTO THE LATE NIGHT HRS. HIGH PRESSURE AND 
SOME GUSTY NW WINDS ON WED...W/ MORE QUIET WX ON THU AND FRI.

&&

.MARINE...

NO PROBS ON THE WATERS TDA. WINDS SHOULD INCRS TO ARND 15 KT THIS
AFTN AFTR SKIES BEGIN TO CLR. 

HIGH PRESSURE WILL HANG TIGHT OVER NEW ENGLAND AND INTO THE MID ATLC 
REGION ON SUN...THOUGH THE INCREASING PRES GRADIENT OVER DELMARVA 
WILL ALLOW THE ELY FLOW TO RISE JUST INTO SCA RANGE FOR MUCH OF THE 
MD BAY FROM THE PREDAWN HRS SUN THRU LATE EVE. WINDS WILL THEN SLACK 
OFF FOR THE OVERNIGHT HRS AS THE HIGH MOVES OFF THE COAST AND WINDS 
TURN SLY. A COLD FRONT WILL PUSH THRU THE REGION LATE TUE...BRINGING 
SOME SCATTERED SHOWERS AND POSSIBLY SOME ISOLATED TSTMS JUST SOUTH 
OF THE METRO DC AREA. BREEZY NW WINDS OF WED AFTN...THOUGH HIGH 
PRESSURE WILL AGAIN OVERTAKE THE REGION FOR THE SECOND HALF OF THE 
WEEK. 

&&

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

&&

$$
PRODUCT...WOODY!/GMS







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