899
FXUS61 KLWX 061424
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1024 AM EDT SAT JUN 6 2026
WHAT HAS CHANGED
A LINE OF SHOWERS HAS DEVELOPED IN THE PAST HOUR OR SO FROM
FREDERICK AND CARROLL COUNTIES IN MARYLAND SOUTHWEST TO
JEFFERSON COUNTY WEST VIRGINIA AND NORTHWESTERN LOUDOUN COUNTY
IN VIRGINIA. WHILE THERE IS STILL A CHANCE FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TO DEVELOP AROUND MID-AFTERNOON
FURTHER TO THE WEST AND NORTH, MOST OF THE STRONGER AND MORE
INTENSE SHOWERS AND THUNDERSTORMS SHOULD BE LATE THIS AFTERNOON
THROUGH EARLY EVENING. SMALL CRAFT ADVISORIES REMAIN IN EFFECT
OVER THE UPPER WATERS THROUGH EARLY EVENING. HEAT INDICES MAY
BRIEFLY APPROACH 95 DEGREES BETWEEN 3PM AND 6PM IN A FEW SPOTS.
KEY MESSAGES
- 1) A STRONG TO SEVERE THUNDERSTORM THREAT GLANCES NORTHERN
PORTIONS OF THE REGION LATE THIS AFTERNOON INTO THIS EVENING.
- 2) EARLY SUMMER HEAT CONTINUES THROUGH THE WEEKEND.
- 3) TEMPERATURES BRIEFLY DROP EARLY NEXT WEEK BEFORE INCREASING
LATE IN THE WEEK.
DISCUSSION
KEY MESSAGE 1...A STRONG TO SEVERE THUNDERSTORM THREAT GLANCES
NORTHERN PORTIONS OF THE REGION LATE THIS AFTERNOON INTO THIS
EVENING.
A SURFACE TROUGH OF LOW PRESSURE AND A LITTLE WIND SHEAR HAVE
ALLOWED FOR AN ENVIRONMENT TO SUPPORT A LINE OF SHOWERS ACROSS
CENTRAL MARYLAND, EASTERN PANHANDLE OF WEST VIRGINIA, AND PARTS
OF NORTHEASTERN VIRGINIA DURING THE MIDDLE PART OF THIS MORNING.
NO LIGHTNING WITH THIS ACTIVITY...PERHAPS JUST A BRIEF DOWNPOUR
OR A WIND GUST OVER 35 MPH. IN THE MEANTIME, AN UPPER TROUGH OF
LOW PRESSURE WILL CONTINUE TO SWING SOUTHEAST ACROSS THE LOWER
GREAT LAKES WITH A TRAILING COLD FRONT THAT IS EXPECTED TO MOVE
SLOWLY INTO AND THROUGH THE REGION LATER TODAY THROUGH EARLY
SUNDAY.
DEWPOINT TEMPERATURES ARE CLIMBING THROUGH THE UPPER 50S AND
INTO THE MIDDLE 60S. CURRENTLY, THERE IS VERY LITTLE
INSTABILITY, BUT THAT COULD SOON CHANGE AS TEMPERATURES CLIMB
INTO THE 80S TO THE LOWER 90S IN PLACES. THE HIGHEST CHANCE OF
STRONG TO SEVERE THUNDERSTORMS TO DEVELOP AND FEED OFF OF THIS
INSTABILITY AND SOME WIND SHEAR WILL BE ALONG AND NORTH OF I-66.
MID-LEVEL (I.E. 700-500 HPA) FLOW INCREASES TO 30-40 KNOTS THIS
AFTERNOON INTO THIS EVENING NEAR THE MASON-DIXON LINE AS THE
UPPER TROUGH TO THE NORTHWEST ENCROACHES ON RIDGING TO THE
SOUTHEAST. LOW- AND MID-LEVEL LAPSE RATES STEEPEN ACCORDINGLY
WITH THE HEIGHT FALLS ALOFT AND ROBUST DIURNAL HEATING. RAP
FORECAST SOUNDINGS INDICATE PRE-CONVECTIVE LAPSE RATES AROUND 7
DEG C/KM, STEEPEST IN THE MID-LEVELS IN THE I-70 CORRIDOR AND
STEEPEST IN THE LOW-LEVEL SOUTH OF I-66/US-50. THIS IS FAVORABLE
FOR GUSTY TO DAMAGING DOWNBURST WINDS IN ANY STORMS THAT MANAGE
TO DEVELOP, WITH STORM COVERAGE AND TIMING STILL SOMEWHAT IN
QUESTION GIVEN A LACK OF STRONGER ASCENT LOCALLY.
MOST GUIDANCE INDICATES THE HIGHEST CHANCES OF CONVECTION THIS
EVENING. HOWEVER, SOME MEMBERS (I.E. WRF-ARW, RAP) HAVE
CONVECTION DEVELOPING A FEW HOURS EARLIER. IF CONVECTION
DEVELOPS A BIT EARLIER (MID AFTERNOON) NEAR THE APPALACHIANS, IT
WOULD MOVE EASTWARD DURING OR JUST AFTER PEAK HEATING. THIS
WOULD INCREASE THE DAMAGING WIND THREAT CONDITIONALLY, THOUGH
OVERALL FORCING WILL BE RATHER WEAK. FORCING INCREASES A BIT
THIS EVENING, BUT THE LOSS OF DIURNAL HEATING MAY CAUSE STORMS
AND THEIR WIND THREAT TO TREND DOWN, SHOULD THE LATER TIMING PAN
OUT.
ALL IN ALL, THIS RESULT IN A RISK OF A FEW STRONG TO LOCALLY
SEVERE STORMS MAINLY IN THE I-68/I-70 CORRIDOR OF NORTHERN AND
WESTERN MD, PERHAPS DOWN INTO THE EASTERN WV PANHANDLE, FAR
NORTHERN VA, AND THE BALTIMORE METRO. DAMAGING WIND GUSTS APPEAR
TO BE THE MAIN THREAT, THOUGH LAPSE RATES/SHEAR ALOFT LEND TO A
CONDITIONAL RISK OF SOME HAIL PARTICULARLY IN STRONGER, MORE
ISOLATED UPDRAFTS/MARGINAL SUPERCELL STRUCTURES, SHOULD THEY
FORM AND IMPACT OUR AREA. THE CHANCE OF RAIN DROPS OFF RATHER
SIGNIFICANTLY FURTHER SOUTH (I.E. SOUTH OF I-66/US-50) DUE TO
FORCING BEING DISPLACED TO THE NORTH THROUGH PEAK HEATING.
A FEW SHOWERS MAY LINGER AS THE FRONT NEARS THE AREA FROM THE
NORTH TONIGHT, BUT THE THREAT FOR SEVERE WEATHER OR EVEN THUNDER
LOOKS RATHER LOW BEYOND LATE EVENING, BARRING ANY GREATER-THAN-
EXPECTED UPSTREAM ORGANIZATION.
FOR SUNDAY, THE COLD FRONT MAY REMAIN NEAR ENOUGH TO TRIGGER A
FEW SHOWERS AND THUNDERSTORMS SOUTH OF I-66/US-50. MODERATE DEEP
LAYER FLOW AND STEEPENING LAPSE RATES WILL AGAIN LEND TO A RISK
OF A FEW STRONG TO DAMAGING THUNDERSTORM GUSTS, THOUGH LAPSE
RATES ALOFT WON'T BE QUITE AS STEEP SO THE HAIL THREAT IS LOWER.
KEY MESSAGE 2...EARLY SUMMER HEAT CONTINUES THROUGH THE WEEKEND.
DESPITE SOME HIGH CLOUDS AND GRADUALLY FALLING HEIGHTS WITH THE
APPROACH OF A COLD FRONT, WELL ABOVE NORMAL TEMPERATURES WILL
PERSIST THROUGH THE WEEKEND AS ANY APPRECIABLE COLD ADVECTION
LAGS AND RAIN REMAINS RELATIVELY SPOTTY AND BRIEF.
HIGH TEMPERATURES ARE EXPECTED TO REACH THE UPPER 80S AND LOWER
TO MIDDLE 90S ACROSS MUCH OF THE REGION THIS AFTERNOON, WITH 70S
OVER THE HIGHER ELEVATIONS. DEW POINTS IN THE UPPER 50S TO LOWER
60S SHOULD KEEP HEAT INDEX VALUES NEAR THE AIR TEMPERATURE, BUT
A FEW READINGS AROUND 95 ARE POSSIBLE MID TO LATE AFTERNOON.
THE DRIER NATURE OF THE AIRMASS ALLOWS TEMPERATURES TO FALL INTO
THE 60S TO LOWER 70S TONIGHT BEFORE REBOUNDING INTO THE UPPER
80S TO LOWER 90S (70S MOUNTAINS) ON SUNDAY. AGAIN, DEW POINTS IN
THE UPPER 50S TO LOWER 60S WILL HOLD HEAT INDEX VALUES CLOSE TO
THE AMBIENT AIR TEMPERATURES.
LOW TEMPERATURES WILL LIKELY FALL INTO THE 60S (50S MOUNTAINS)
SUNDAY NIGHT AS A COLD FRONT PRESSES FURTHER SOUTH.
KEY MESSAGE 3...TEMPERATURES BRIEFLY DROP EARLY NEXT WEEK BEFORE
INCREASING LATE IN THE WEEK.
AN UPPER-LEVEL TROUGH AND LOW-LEVEL ONSHORE FLOW BEHIND A
SURFACE COLD FRONT WILL BRING COOLER TEMPERATURES MONDAY INTO
TUE (WIDESPREAD 80S/COOLER IN MOUNTAINS). OVERNIGHT LOWS WILL BE
IN THE 50S AND 60S.
UPPER-LEVEL RIDGING BUILDS IN WEDNESDAY ONWARD WITH SURFACE
TEMPERATURES INCREASING DAILY. TEMPERATURES LOOK TO REBOUND TO
THE 90S BY THURSDAY INTO NEXT WEEKEND. MOISTURE RETURNS WITH
THE INCREASE IN TEMPERATURES RESULTING IN AN UPTICK IN
HUMIDITY. DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS LOOK TO
IMPACT THE AREA DAILY THURSDAY ONWARD, WITH PERHAPS A HIGHER
CHANCE FRIDAY WITH AN UPPER-LEVEL DISTURBANCE APPROACHING.
AVIATION /14Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS ARE LIKELY AT THE TAF SITES THROUGH THIS
AFTERNOON AS HIGH PRESSURE GRADUALLY DEPARTS OFF THE ATLANTIC
COAST. WINDS WILL BE GENERALLY SW, WITH A MORE S COMPONENT EAST
OF A SURFACE TROUGH AND A MORE W COMPONENT TO THE WEST. METRO
TAF SITES SUCH AS KBWI/KMTN/KDCA WOULD BE MOST LIKELY TO SEE A
BIT MORE S COMPONENT. GIVEN DECENT VERTICAL MIXING, GUSTS UP TO
20 KNOTS ARE POSSIBLE, ESPECIALLY DURING THE AFTERNOON HOURS
(SLIGHTLY LOWER AT KCHO). SHOWER AND THUNDERSTORM CHANCES
INCREASE THIS EVENING, WITH KMRB TO KMTN SEEING THE HIGHEST CHANCE
FOR RESTRICTIONS. FURTHER SOUTH, HIGH-RESOLUTION MODELS DEPICT
A WEAKENING TREND INTO THE NIGHT. ALTHOUGH THE CONSENSUS HAS
TS PROBS PEAKING IN THE EVENING, A FEW MEMBERS INDICATE CI A FEW
HOURS EARLIER. WILL MONITOR FOR POSSIBLE AMDS. ANY RESTRICTIONS
OR GUSTY WINDS IN/NEAR STORMS SHOULD BE BRIEF (SUB-HOURLY).
WINDS SHIFT TO NORTHWESTERLY BEHIND THE FRONT MIDDAY SUNDAY WITH
ANY CONVECTIVE CHANCES MAINLY NEAR KCHO. HIGH PRESSURE BUILDING
TO THE NORTH WILL YIELD MAINLY NORTH TO NORTHEASTERLY WINDS INTO
SUNDAY INTO MONDAY WITH CONTINUED VFR CONDITIONS. SOME LOW CIGS
CAN'T BE RULED OUT MONDAY NIGHT IN ONSHORE FLOW.
VFR IS EXPECTED TO PREVAIL TUESDAY INTO WEDNESDAY WITH S WINDS
POSSIBLY GUSTING 15-20 KTS EACH AFTERNOON.
MARINE
GENERALLY S/SW FLOW IS EXPECTED THIS AFTERNOON, BECOMING MORE
W/NW BY LATE TONIGHT. ALTHOUGH THE HIGHEST LIKELIHOOD OF GUSTS
TO AROUND 20 KTS IS MID TO LATE AFTERNOON, FORECAST SOUNDINGS
INDICATE POTENTIAL FOR DEEP ENOUGH MIXING TO RESULT IN GUSTINESS
AS EARLY AS LATE MORNING, WITH A MODEST INCREASE IN LOW-LEVEL
FLOW HEADING INTO EARLY EVENING AHEAD OF AN APPROACHING COLD
FRONT. HAVE THEREFORE ISSUED SCAS FOR THE UPPER WATERS COVERING
11AM TO 8PM. A FEW GUSTY SHOWERS AND THUNDERSTORMS MAY APPROACH
THE WATERS LATE AFTERNOON INTO THIS EVENING, WITH A FEW SMWS
POSSIBLE (AGAIN MAINLY TO THE NORTH).
WINDS TURN NW SUNDAY, N SUNDAY NIGHT, THEN NE TO E MONDAY. GUSTS
COULD AGAIN APPROACH SCA LEVELS BRIEFLY SUNDAY AFTERNOON. MORE
WIDESPREAD GUSTINESS IS PROBABLE MONDAY IN ONSHORE FLOW. WINDS SHIFT
TO SOUTHERLY TUESDAY INTO WEDNESDAY WITH ADDITIONAL SCAS POSSIBLE.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MDZ008.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ530-
531-535-538.
DISCUSSION...BRO/KLW/DHOF
AVIATION...BRO/KLW/DHOF
MARINE...BRO/KLW/DHOF
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page