959
FXUS61 KLWX 081429
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1029 AM EDT THU MAY 8 2025
SYNOPSIS
COLD FRONT SLOWLY CROSSES THE MID ATLANTIC BETWEEN THIS
AFTERNOON AND FRIDAY MORNING. HIGH PRESSURE FOR THE WEEKEND AND
MONDAY. THEN LOW PRESSURE IS EXPECTED TO MOVE UP FROM THE DEEP
SOUTH FOR MID WEEK.
NEAR TERM /UNTIL 6 PM THIS EVENING/
12Z KIAD SOUNDING SHOWS SATURATION BETWEEN 850-700MB, WITH
VISIBLE SATELLITE AS OF 10:20AM SHOWING CUMULUS CLOUDS
DEVELOPING ACROSS THE FORECAST AREA. SATURATION WILL CONTINUE TO
LEAD TO SCATTERED TO BROKEN CLOUD DECKS ACROSS THE AREA THROUGH
THE DAY WITH CLOUD COVER EXPECTED TO INCREASE THIS AFTERNOON.
NO CHANGES WERE MADE TO THE FORECAST WITH THE PREVIOUS FORECAST
DISCUSSION BELOW.
A COLD FRONT BACK TOWARDS PITTSBURGH EARLY THIS MORNING WILL
PUSH INTO FAR WESTERN MD IN THE EARLY AFTERNOON. IT THEN SLOWLY
MOVES ACROSS OUR AREA TO NEAR THE COAST BY EARLY MORNING FRIDAY.
HOWEVER WITH A 500MB TROF MOVING IN FROM THE NW, THAT FRONT
WILL BUCKLE AND FORM A COASTAL LOW AROUND THE MID ATLANTIC COAST
THAT WILL MOVE TO NEAR NEW YORK CITY BY FRIDAY EVENING. ALL OF
THAT WILL PROVIDE SHOWERS AND THUNDERSTORMS FOR US, THAT SHOULD
START TO FIRE MID AFTERNOON TODAY AND PERSIST INTO FRIDAY BEFORE
DRYING OUT FOR THE WEEKEND.
WE DO HAVE A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A GOOD
PART OF OUR FORECAST AREA, WITH THE HIGHER SLIGHT RISK OVER SW
VA AND THE SMOKIES. FOR US, THE INSTABILITY ISNT GREAT, ABOUT
500-1000 J/KG, BUT WITH SHEAR AROUND 30 KNOTS, A FEW SEVERE
STORMS CAN'T BE RULED OUT. THE 0Z HREF FIELDS FOR STRONG UPDRAFTS
AND UPDRAFT HELICITY AREN'T VERY STRONG, BUT THERE ARE HINTS. SO
MARGINAL SEEMS TO BE THE RIGHT LEVEL HERE. TIMEFRAME WOULD BE
LATE THIS AFTERNOON THROUGH THE EVENING.
ALSO WE HAVE A MARGINAL RISK OF EXCESSIVE RAIN, WHICH AGAIN
IS APPROPRIATE. PWATS ARE SEASONALLY HIGH, AND THERE COULD BE
SOME TRAINING ASPECTS. THE HREF LPMM AND GLOBAL ENSEMBLE CHANCES
FOR 1 INCH IN 24 HOURS DON'T JUMP OFF THE PAGE FOR A LOT OF
FLOODING, BUT IF A LONGER LASTING HEAVIER STORM FELL ACROSS A
FLOOD PRONE AREA OR A CITY, SOME INSTANCES OF FLOODING ARE
POSSIBLE TONIGHT.
SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/
SHOWERS AND STORMS PERSIST INTO FRIDAY BEFORE PULLING AWAY. THAT
COULD SLOW IF THE COASTAL LOW IS SLOWER TO MOVE OUT THAN
CURRENTLY FORECAST. DRY WEATHER AND HIGH PRESSURE RETURN FOR
SATURDAY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
SURFACE HIGH PRESSURE CENTERED OVER PA/NY AND MID-LEVEL RIDGING ATOP
THE AREA ON SUNDAY KEEP CONDITIONS DRY AND SEASONAL. HIGHS SUNDAY
REACH THE MID TO UPPER 70S, THEN DOWN TO THE 50S SUNDAY NIGHT. THE
HIGH SLIDES OFFSHORE AT THE START OF NEXT WEEK, USHERING IN
SOUTHERLY FLOW THAT ADVECTS IN HIGHER DEW POINT AIRMASS.
ADDITIONALLY, A CUTOFF UPPER LOW OVER THE SOUTHERN PLAINS SLOWLY
MEANDERS NORTHEAST TOWARD THE TN VALLEY EARLY NEXT WEEK.
THE OUTER INFLUENCE OF THE UPPER LOW REACHES THE AREA MONDAY
AFTERNOON TO EVENING, WHICH COULD PRODUCE SCATTERED
SHOWERS/THUNDERSTORMS ALONG AND SOUTH OF I-66. THE UPPER LOW GETS
CLOSER ON TUESDAY, WITH HIGH RAIN CHANCES FOR THE ENTIRE AREA. THE
LOW PUSHES OVERHEAD THEN EAST OF THE AREA ON WEDNESDAY, THOUGH
TRAILING SHOWERS ON THE BACKSIDE CONTINUE THROUGH THE MIDDLE OF NEXT
WEEK. THE PRESENCE OF PRECIPITATION AND ABUNDANT CLOUD COVER KEEP
HIGHS IN THE 70S TUESDAY AND WEDNESDAY, WITH MILD OVERNIGHT LOWS
SETTLING IN THE 60S.
AVIATION /15Z THURSDAY THROUGH MONDAY/
VFR TO START TODAY, BUT THAT DEGRADES INTO IFR CIGS TONIGHT
WITH SHOWERS AND THUNDERSTORMS. WINDS WILL BE LIGHT TODAY, BUT
THEN NORTHWEST GUSTS AROUND 15-20KTS FRI AFTERNOON THROUGH SAT
MORNING
VFR CONDITIONS ARE EXPECTED FOR THE SECOND HALF OF THE WEEKEND INTO
THE START OF NEXT WEEK. HIGH PRESSURE OVERHEAD MOVES OFFSHORE,
CAUSING WINDS TO BECOME SOUTHERLY ON MONDAY. THIS BRINGS IN WARMER
TEMPS AND INSTABILITY, LEADING TO SCATTERED SHOWERS AND
THUNDERSTORMS MONDAY AFTERNOON/EVENING.
MARINE
LIGHT WINDS TODAY AND TONIGHT. HOWEVER, A SMALL CRAFT ADVISORY
WILL LIKELY BE NEEDED FOR FRIDAY AFTERNOON THROUGH SATURDAY
MORNING AS COASTAL LOW PRESSURE PULLS AWAY FROM OUR AREA.
FAVORABLE MARINE CONDITIONS TO END THE WEEK AS HIGH PRESSURE
MAINTAINS WINDS AT 5-10 KNOTS. AS THE HIGH MOVES OFFSHORE WINDS TURN
SOUTHERLY FOR MONDAY, AND THIS COULD CAUSE GUSTS TO APPROACH 15
KNOTS MONDAY NIGHT. SCATTERED SHOWERS AND THUNDERSTORMS RETURN TO
THE FORECAST FOR MONDAY AFTERNOON.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...CS
NEAR TERM...CS/AVS
SHORT TERM...CS
LONG TERM...KRR
AVIATION...CS/KRR
MARINE...CS/KRR
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