016
FXUS61 KLWX 280745
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
345 AM EDT TUE APR 28 2026
WHAT HAS CHANGED
HAVE RAISED SHOWER CHANCES THROUGH THE MID-MORNING AS A SWATH OF
PRECIPITATION REMAINS INTACT WEST OF THE APPALACHIANS. FOR THE
AFTERNOON PERIOD, MODELS HAVE TRENDED DOWNWARD WHICH SHOULD
FAVOR A MAINLY DRY DAY. ON WEDNESDAY, THE MARGINAL RISK FOR
SEVERE THUNDERSTORMS WAS EXPANDED NORTHWARD NEAR THE MASON-
DIXON LINE IN NORTHEASTERN MARYLAND.
KEY MESSAGES
1) INCREASING SHOWER AND THUNDERSTORM CHANCES THROUGH MID-WEEK
AS A FRONTAL SYSTEM APPROACHES.
2) MULTIPLE NIGHTS OF FROST/FREEZING CONDITIONS POSSIBLE LATE
WEEK INTO THE WEEKEND.
3) ADDITIONAL RAIN CHANCES FRIDAY INTO SATURDAY AS A TRAILING
DISTURBANCE PASSES THROUGH.
DISCUSSION
KEY MESSAGE 1...INCREASING SHOWER AND THUNDERSTORM CHANCES
THROUGH MID-WEEK AS A FRONTAL SYSTEM APPROACHES.
WHILE THE WEATHER IS CURRENTLY QUIET ACROSS THE MID-ATLANTIC
REGION, THE BROADER VIEW ON THE RADAR MOSAIC SHOWS QUITE A
DIFFERENT STORY TO THE WEST. AS OF 07Z/3 AM, WHILE THERE HAS
BEEN A DOWNWARD TREND IN CONVECTIVE INTENSITY, SOME SEVERE
THUNDERSTORMS ARE CURRENTLY RACING ACROSS EASTERN KENTUCKY INTO
SOUTHWESTERN WEST VIRGINIA. MOST NOTABLY, A MESOSCALE CONVECTIVE
VORTEX (MCV) IS SPINNING CYCLONICALLY WITHIN THE MORE INTENSE
BAND OF STORMS. WHILE A BRUNT OF THIS LARGER SWATH OF SHOWERS
IS MOVING TOWARD THE EAST, THE EMBEDDED CONVECTIVE COMPLEX IS
TAKING A MORE SOUTHEASTWARD TRACK ALONG THE INSTABILITY
GRADIENT. WITH THE LOCAL REGION IN A STABLE THERMODYNAMIC
ENVIRONMENT, THE EXPECTATION IS SHOWERS WILL CONTINUE TO WEAKEN
WHILE REACHING THE ALLEGHENIES IN THE NEXT COUPLE HOURS. AS
SHOWN BY THE 00Z HREF PROBABILITIES, MEASURABLE RAINFALL
DIMINISHES WITH EASTWARD EXTENT THIS MORNING.
BESIDES THE NOTED COMPLEX TO THE WEST, HIGH CLOUDS WILL CONTINUE
TO OVERSPREAD THE REGION EARLY THIS MORNING. THIS INCREASE IN
CLOUDS COUPLED WITH LIGHT SOUTH TO SOUTHEASTERLIES HAS YIELDED
MILDER CONDITIONS THAN LAST NIGHT. MOST SPOTS ARE HOLDING STEADY
IN THE MID 40S TO LOW 50S. PER UPSTREAM WATER VAPOR CHANNEL
TRENDS, MOISTURE SHOULD BE ON THE INCREASE AHEAD OF THE
APPROACHING LONGWAVE TROUGH. AS SUCH, EXPECT THICKENING MID/HIGH
CLOUDS TODAY WHICH SHOULD HELP CAP HIGH TEMPERATURES IN THE
60S, LOCALLY HITTING THE LOW 70S ACROSS THE ALLEGHENY MOUNTAIN
VALLEYS. LOOKING AT SHOWER CHANCES, THERE HAS CERTAINLY BEEN A
DOWNWARD TREND IN RECENT MODEL CYCLES. ASIDE FROM SOME ISOLATED
SHOWERS, MUCH OF THE AFTERNOON/EVENING SHOULD STAY FAIRLY DRY.
MOSTLY CLOUDY SKIES CONTINUE INTO THE NIGHT WITH FORECAST LOWS
IN THE UPPER 40S TO LOW 50S.
WEDNESDAY CONTINUES TO PRESENT ITSELF AS THE MOST ACTIVE DAY OF
THE FORECAST PERIOD. AS IS COMMON IN CONVECTIVE FORECASTING IN
THE AREA, MORNING CLOUDS/SHOWERS MAY HINDER THE AFTERNOON SEVERE
WEATHER POTENTIAL. STARTING OFF THE DAY, WARM ADVECTION SHOWERS
WILL OVERSPREAD THE AREA FROM SOUTHWEST TO NORTHEAST. THE ACTUAL
SURFACE WARM FRONT SHOULD RESIDE OVER SOUTHWESTERN VIRGINIA
AROUND DAYBREAK. THROUGH THE DAY, EXPECT THIS WARM FRONT TO
SLOWLY LIFT NORTHEASTWARD IN TIME BEFORE REACHING THE METRO
AREAS BY WEDNESDAY EVENING. GIVEN THE LATER ARRIVAL OF THIS
MILDER/MORE UNSTABLE AIR MASS, THIS MIGHT NOT TIME AS WELL WITH
THE PEAK DIURNAL HEATING CYCLE. IF ANYTHING, THE BETTER SHOT
WOULD COME DURING THE EVENING AS A COLD FRONT PUSHES EASTWARD
ACROSS THE REGION. DESPITE QUESTIONABLE INSTABILITY, THE 0-6 KM
SHEAR RUNS AROUND 45 TO 55 KNOTS WHICH IS PLENTY SUFFICIENT FOR
SEVERE THUNDERSTORM DEVELOPMENT. THUS, THERE IS A RISK OF SOME
DAMAGING WINDS AS THIS COLD FRONT TRACKS THROUGH ON WEDNESDAY
EVENING. A MARGINAL RISK CONTINUES TO BE ADVERTISED BY THE
STORM PREDICTION CENTER.
SHOWERS AND A FEW THUNDERSTORMS LINGER INTO THE OVERNIGHT HOURS.
HOWEVER, THE AREA SHOULD EXPERIENCE A DRYING TREND FROM WEST TO
EAST BEHIND THIS EXITING BAROCLINIC ZONE. A COOL AND BREEZY DAY
LIES AHEAD FOR THURSDAY WITH NORTHWESTERLY GUSTS TO AROUND 20 TO
30 MPH. DESPITE THE LARGE DROP IN 850-MB TEMPERATURES (8 TO 10C
FALL BETWEEN WEDNESDAY AND THURSDAY AFTERNOONS), A WELL MIXED
BOUNDARY LAYER SHOULD OVERCOME THIS COOLING EFFECT. FORECAST
HIGHS ON THURSDAY SHOULD PUSH INTO THE UPPER 50S TO MID 60S (40S
TO MID 50S ACROSS THE MOUNTAINS). OUTSIDE OF SOME UPSLOPE AIDED
RAIN SHOWERS ALONG/WEST OF THE ALLEGHENIES, EXPECT A DRY DAY.
NIGHTTIME CONDITIONS YIELD LOWS FALLING INTO THE MID 30S TO MID
40S.
KEY MESSAGE 2...MULTIPLE NIGHTS OF FROST/FREEZING CONDITIONS POSSIBLE
LATE WEEK INTO THE WEEKEND.
HIGH PRESSURE WILL BUILD IN ACROSS THE REGION BEHIND A DEPARTING
CLOSED LOW PRESSURE SYSTEM. COOL AIR ADVECTION, DRIER AIR, AND
DIMINISHING WINDS COULD ALL LEAD TO POSSIBLE FROST FORMATION IN
PARTS OF THE REGION FRIDAY NIGHT THROUGH SUNDAY NIGHT. FREEZING
TEMPERATURES COULD ALSO EVOLVE AND SPREAD EASTWARD TOWARD THE MORE
POPULATED AREAS OUTSIDE OF THE ALLEGHENIES. LOW TEMPERATURES EACH
NIGHT COULD BE WIDESPREAD 30S WITH LOWER 40S WELL TO THE EAST. WE
WILL SEE A SLIGHT UPTICK IN THE WINDS DURING THE DAY DUE TO DIURNAL
DIFFERENCES, BUT THEN BECOME LIGHT TO CALM WIDESPREAD AFTER SUNSET
EACH DAY.
KEY MESSAGE 3...ADDITIONAL RAIN CHANCES FRIDAY INTO SATURDAY AS
A TRAILING DISTURBANCE PASSES THROUGH.
AS THE MAIN TROUGH OF LOW PRESSURE PULLS AWAY FROM THE REGION, A
TRAILING DISTURBANCE OR TWO COULD FOLLOW SUIT AND BRING US A FEW
RAIN SHOWERS TO THE REGION BOTH FRIDAY AND SATURDAY. IT IS NOT OUT
OF THE QUESTION THAT HIGHER ELEVATIONS IN THE ALLEGHENIES COULD
ENCOUNTER A LITTLE LIGHT RAIN AND SNOW MIX BUT ACCUMULATIONS WOULD
BE LIGHT. THERE IS EVEN A HINT THAT A DISTURBANCE COULD MOVE ACROSS
THE REGION EARLY NEXT WEEK AND BRING US A LITTLE MORE RAIN RELIEF.
TEMPERATURES WOULD BE MORE SEASONABLE EARLY NEXT WEEK.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
AS HIGH PRESSURE DEPARTS THE ATLANTIC COAST, VFR CONDITIONS
REMAIN ACROSS ALL TERMINALS EARLY THIS MORNING. AN APPROACHING
COMPLEX OF SHOWERS AND THUNDERSTORMS SHOULD REACH THE
ALLEGHENIES IN THE NEXT HOUR OR TWO. HOWEVER, A STABLE
ATMOSPHERE WILL HELP LEAD TO A DRAMATIC WEAKENING TREND. THE
MOST LIKELY TIME FOR THESE SHOWERS TO REACH THE WESTERN TAF
SITES (KCHO AND KMRB) WOULD BE AROUND 12-15Z. IF CEILINGS LOWER
ENOUGH, BRIEF RESTRICTIONS CANNOT BE RULED OUT. THE D.C.
TERMINALS COULD SEE A FEW RESIDUAL SHOWERS DURING THE MORNING,
BUT CONFIDENCE IS LOW. THE OVERALL AFTERNOON/EVENING FORECAST
HAS TRENDED DRIER SO HAVE REMOVED THE PROB30 GROUPS FOR SHOWERS.
OVERALL WINDS TODAY WILL BEGIN OUT OF THE SOUTH BEFORE SHIFTING
TO THE SOUTHEAST INTO TONIGHT.
WIDESPREAD RAIN SHOWERS AND SOME LATE AFTERNOON TO EVENING
THUNDERSTORMS ARE IN THE FORECAST FOR WEDNESDAY. RESRICTIONS
LOOK LIKELY FOR LARGE PORTIONS OF THE DAY. ANY SEVERE
THUNDERSTORMS WOULD BE CAPABLE OF DAMAGING WIND GUSTS. EXPECT
MAINLY SOUTHEASTERLY WINDS THROUGH THE DAY WITH AFTERNOON GUSTS
UP TO AROUND 15 TO 20 KNOTS. WINDS SHIFT TO WEST TO
NORTHWESTERLY ON WEDNESDAY NIGHT BEHIND A STRONG COLD FRONT. VFR
CONDITIONS ARE LIKELY ON THURSDAY WITH CONTINUED NORTHWESTERLY
GUSTS TO 20 TO 25 KNOTS.
SUB-VFR CONDITIONS COULD OCCUR AT A FEW OF THE TERMINALS DEPENDING
ON RAIN SHOWER COVERAGE FRIDAY AND AGAIN ON SATURDAY. OTHERWISE,
TERMINALS THAT DO NOT ENCOUNTER THESE BRIEF BURSTS OF RAIN SHOWERS
COULD STAY VFR. WINDS NORTHWEST 10 TO 15 KNOTS GUSTS UP TO 20 KNOTS
FRIDAY AND THEN AGAIN ON SATURDAY. WINDS WILL DIMINISH EACH
NIGHT.
MARINE
SUB-ADVISORY LEVEL WINDS CONTINUE THIS MORNING WITH
SOUTHEASTERLY GUSTS UP TO 10 TO 15 KNOTS. ANY MARINE HAZARDS
LIKELY HOLD OFF UNTIL WEDNESDAY AFTERNOON AS SOUTHEASTERLIES
RAMP UP FURTHER. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED
DURING THIS UPTICK, WITH FURTHER WIND INCREASES INTO WEDNESDAY
NIGHT AND THURSDAY AS WINDS SHIFT TO NORTHWESTERLY BEHIND A COLD
FRONT. GUSTS UP TO 20 TO 25 KNOTS ARE POSSIBLE IN THIS POST-
FRONTAL ENVIRONMENT. BEFORE THIS COLD FRONT CROSSES THE WATERS
LATE WEDNESDAY, SOME SEVERE WEATHER POTENTIAL EXISTS WHICH MAY
WARRANT A FEW SPECIAL MARINE WARNINGS.
SMALL CRAFT ADVISORIES ARE LIKELY NEEDED THROUGH THURSDAY
AFTERNOON AND INTO THE EARLY EVENING. WHILE MOST MARINE ZONES
SEE WINDS DROP OFF INTO THE NIGHT, WINDS COULD REMAIN ELEVATED
OVER THE SOUTHERN MOST WATERS.
SMALL CRAFT ADVISORIES POSSIBLE FRIDAY AND AGAIN ON SATURDAY,
PRIMARILY IN THE NORTHERN CHESAPEAKE BAY. WINDS NORTHWEST 10 TO
15 KNOTS GUSTS 20 KNOTS EACH DAY.
TIDES/COASTAL FLOODING
ONSHORE FLOW CONTINUES AS HIGH PRESSURE EXITS THE ATLANTIC COAST ND
WAVES OF LOW PRESSURE APPROACH FROM THE WEST. MANY LOCATIONS
WILL REACH ACTION STAGE DURING HIGH TIDE THROUGH WEDNESDAY, WITH
MINOR TIDAL FLOODING POSSIBLE, ESPECIALLY AT ANNAPOLIS AND
DAHLGREN. A COUPLE OTHER TIDAL SITES LIKE ALEXANDRIA AND HAVRE
DE GRACE COULD GET CLOSE DURING THE HIGHER OF THE TWO
ASTRONOMICAL HIGH TIDES, AS WELL. WATER LEVELS BEGIN TO DROP OFF
BY THURSDAY AS WINDS SHIFT TO NORTHWESTERLY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...BRO/KLW
AVIATION...BRO/KLW
MARINE...BRO/KLW
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