060
FXUS61 KLWX 271300
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
900 AM EDT SAT JUN 27 2026
WHAT HAS CHANGED
RAISED PRECIPITATION CHANCES ACROSS THE SHENANDOAH VALLEY INTO
THE CENTRAL VIRGINIA PIEDMONT AND SOUTHERN MARYLAND THROUGH LATE
THIS MORNING WITH AN ONGOING BATCH OF SHOWERS. OTHERWISE, THE
FORECAST REMAINS LARGELY ON TRACK. WILL BE MONITORING HEAVY RAIN
POTENTIAL WITH ANY STORMS THAT DEVELOP WHERE BREAKS OF SUN OCCUR
WHICH MAY ACTUALLY FOCUS IN THE I-70 CORRIDOR LATER TODAY.
KEY MESSAGES
- (1) A WEAK FRONTAL BOUNDARY WILL LINGER ACROSS THE REGION
THROUGH SUNDAY, DELIVERING WAVES OF SHOWERS AND
THUNDERSTORMS.
- (2) EXCESSIVE HEAT AND HUMIDITY NEXT WEEK HEADING INTO THE
INDEPENDENCE DAY HOLIDAY.
DISCUSSION
KEY MESSAGE 1...A WEAK FRONTAL BOUNDARY WILL LINGER ACROSS THE
REGION THROUGH SUNDAY, DELIVERING WAVES OF SHOWERS AND
THUNDERSTORMS.
12Z OBS AND REGIONAL SOUNDINGS INDICATE DEEP MOISTURE IN PLACE.
MODEL GUIDANCE SHOWS PWAT VALUES CLIMBING TO NEAR 2 INCHES OVER
THE COURSE OF THE DAY. AS A RESULT, ANY STORMS WILL BE CAPABLE
OF PRODUCING VERY HEAVY RAINFALL. HOWEVER, QUESTIONS REMAIN
REGARDING HOW MANY STORMS WILL ULTIMATELY FORM, WITH RECENT
MODEL GUIDANCE SHOWING SHOWERS OVER SOUTHERN WV/EASTERN
KY/SOUTHERN OH MOVING OVERHEAD AND PERSISTING ON/OFF THROUGH
MUCH OF THE DAY. IF THIS SOLUTION WERE TO PLAY OUT, IT MAY BE
DIFFICULT FOR DESTABILIZATION TO OCCUR, AND WE MAY LARGELY JUST
END UP WITH CLOUDY SKIES AND ON/OFF SHOWERS. THE BEST CHANCE FOR
SOME BREAKS IN THE CLOUD COVER TO OCCUR THIS AFTERNOON MAY
ACTUALLY BE ACROSS NORTHERN MD, SO WE'LL NEED TO KEEP AN EYE ON
THAT AREA OVER THE COURSE OF THE DAY. WPC CURRENTLY HAS MOST OF
THE FORECAST AREA OUTLOOKED IN A MARGINAL RISK FOR EXCESSIVE
RAINFALL. LITTLE TO NO THREAT FOR SEVERE THUNDERSTORMS IS
EXPECTED WITH THE MINIMAL INSTABILITY AND SATURATED PROFILES
(WHICH SHOULD LIMIT THE STRENGTH OF DOWNDRAFTS). WITH THE AMPLE
CLOUD COVER AND SHOWER ACTIVITY, TEMPERATURES WILL BE COOLER
THAN PRECEDING DAYS, WITH HIGHS IN THE UPPER 70S AND LOWER 80S
FOR MOST.
COVERAGE OF ANY STORMS SHOULD DECREASE THROUGH THE EVENING, BUT
A FEW SHOWERS MAY LINGER THROUGH THE OVERNIGHT HOURS. IN
ADDITION TO LOW CLOUDS, PATCHY FOG MAY BE POSSIBLE LATER
TONIGHT. OVERNIGHT LOW TEMPERATURES WILL BE IN THE MID 60S TO
AROUND 70.
UPPER RIDGING WILL START TO BUILD TO OUR WEST OVER THE
MISSISSIPPI VALLEY AND GREAT LAKES ON SUNDAY. THIS WILL CAUSE
FLOW TO TURN NORTHWESTERLY ALOFT. A WEAK SHORTWAVE DISTURBANCE
IS EXPECTED TO DIVE SOUTHEASTWARD FROM THE GREAT LAKES AND
APPROACH THE AREA FROM THE NORTHWEST. SHOWERS AND THUNDERSTORMS
ARE FORECAST TO DEVELOP ONCE AGAIN AHEAD OF THIS DISTURBANCE
SUNDAY AFTERNOON. COVERAGE OF SHOWERS AND STORMS SHOULD BE MUCH
HIGHER THAN SATURDAY WITH STRONGER DAYTIME HEATING AND LARGE
SCALE ASCENT AHEAD OF THE APPROACHING SHORTWAVE. MODEL SOUNDINGS
SHOW LARGELY SATURATED PROFILES ONCE AGAIN, WITH PWATS STILL
NEAR 2 INCHES. HOWEVER, INSTABILITY IS MUCH GREATER, AT AROUND
1000-2000 J/KG OF MLCAPE. WITH AMPLE INSTABILITY, HIGH PWATS,
AND DEEP WARM CLOUD LAYERS EXTENDING UP TO AROUND 15KFT, STORMS
SHOULD BE CAPABLE OF PRODUCING HEAVY RAINFALL. THE MOST RECENT
RUNS OF THE HRRR AND RRFS SHOW LOCALIZED MAXIMA OF 2-4"
SCATTERED ABOUT THE FORECAST AREA. AS A RESULT, THERE COULD BE A
THREAT FOR FLASH FLOODING IN URBAN AREAS. OUTSIDE OF THE URBAN
AREAS, THE BACKGROUND DROUGHT CONDITIONS SHOULD HELP TO LIMIT
THE THREAT FOR FLOODING. WHILE FLOODING LOOKS TO BE THE GREATER
THREAT, THERE COULD ALSO BE A LOW-END THREAT FOR DAMAGING WINDS,
WITH DCAPE VALUES AROUND 600-800 J/KG.
UPPER RIDGING WILL CONTINUE TO BUILD IN FROM THE WEST ON MONDAY.
COVERAGE OF STORMS IS EXPECTED TO BE LOWER ON MONDAY, WITH MOST
OF THE ACTIVITY LIKELY REMAINING CONFINED TO THE HIGHER TERRAIN
TO THE WEST OF THE BLUE RIDGE.
KEY MESSAGE 2...EXCESSIVE HEAT AND HUMIDITY NEXT WEEK HEADING
INTO THE INDEPENDENCE DAY HOLIDAY.
LOOKING AT A PROLONGED SIGNIFICANT HEAT RISK ACROSS THE ENTIRE
REGION TUESDAY THROUGH THE INDEPENDENCE DAY HOLIDAY/WEEKEND.
STRONG/BROAD SUBTROPICAL HIGH PRESSURE AND A BUILDING UPPER-LEVEL
RIDGE WILL ALLOW TEMPERATURES AND HUMIDITY VALUES TO CLIMB
TOWARD RECORD LEVELS BY THE MIDDLE AND END OF NEXT WEEK.
TEMPERATURES START TO CLIMB TUESDAY AS THE UPPER-LEVEL RIDGE
EXPANDS EASTWARD FROM THE OHIO RIVER VALLEY. LOOK FOR HIGHS IN
THE 90S WITH HEAT INDICES RUNNING BETWEEN 95-100 DEGREES.
WEDNESDAY THROUGH FRIDAY WILL BE THE PEAK OF THE HEAT WITH
HIGHS FOR MOST IN THE UPPER 90S AND LOWER 100S. HEAT INDICES
EACH AFTERNOON WITH RUN BETWEEN 102-107 DEGREES WITH A FEW
READINGS AROUND 110 ALONG THE IMMEDIATE I-95 METRO CORRIDOR AND
DOWN ACROSS THE VA PIEDMONT REGION. MINIMAL RELIEF IS EXPECTED
ACROSS THE MOUNTAINS WITH HIGHS IN THE MID 80S TO LOW 90S AND
HEAT INDICES IN THE MID TO UPPER 90S AS THE HEAT PEAKS MID TO
LATE WEEK. NO RELIEF AT NIGHT EITHER WITH WIDESPREAD LOWS IN THE
UPPER 60S TO MID 70S (UPPER 70S-80 URBAN AREAS) WEDNESDAY
THROUGH SATURDAY. MORE AT WEATHER.GOV/LWX/HEAT.
EVEN WITH THAT SAID, THERE STILL REMAINS SOME SPREAD IN TEMPERATURE
DATA MID TO LATE NEXT WEEK. SOME OF THIS IS DUE TO THE
PLACEMENT AND POSITIONING OF THE RIDGE ALONG WITH ANY T-STORM
CHANCES THAT MAY DEVELOP LATE NEXT WEEK.
RIGHT NOW, ANY CONVECTION LOOKS TO BE TIED TO THE MOUNTAINS
WEDNESDAY AND THURSDAY DUE IN PART TO THE TERRAIN INFLUENCE. WITH
EXCESSIVE HEAT AND HUMIDITY THERE WILL BE PLENTY OF INSTABILITY TO
WORK WITH. YOU COMBINE THIS WITH ANY POTENTIAL RIPPLES OF LOW
PRESSURE MOVING AROUND THE RIDGE OR A BAY/RIVER BREEZE TO GET
CONVECTIVE DEVELOPMENT. THIS IS ILLUSTRATED BY BOTH THE CSU/CIPS
OUTLOOKS ALONG WITH GOOGLE WXNEXT AI MODEL WHICH SUGGEST THE RISK
FOR SEVERE WEATHER DURING THE FRIDAY JULY 3RD AND SATURDAY JULY 4
TIMEFRAME. SOMETHING WE'LL CONTINUE TO MONITOR IN SUBSEQUENT
FORECAST SHIFTS. HISTORICALLY, NEAR RECORD SUMMER HEAT OFTEN
ENDS WITH WIDESPREAD STRONG THUNDERSTORM ACTIVITY, AND LATEST
GUIDANCE STARTS TO BREAK DOWN THE HEAT NEXT WEEKEND (JULY 4).
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
CONDITIONS ARE CURRENTLY VFR AT THE METRO TERMINALS WITH MVFR AT
CHO/MRB. MVFR CEILINGS ARE FORECAST TO BECOME MORE WIDESPREAD,
WITH A PERIOD OF IFR POSSIBLE 14Z-18Z ROUGHLY. ON AND OFF
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THROUGH THE DAY. THE
GREATEST CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON/EVENING
HOURS HAS BEEN HIGHLIGHTED IN THE TAFS WITH PROB30 GROUPS.
PATCHY FOG APPEARS POSSIBLE OVERNIGHT, AND CEILINGS COULD
BRIEFLY APPROACH IFR NEAR DAYBREAK. GRADUAL IMPROVEMENT BACK TO
VFR CEILINGS IS EXPECTED THROUGH THE DAY SUNDAY. ADDITIONAL
SHOWERS AND THUNDERSTORMS MAY DEVELOP SUNDAY AFTERNOON. PATCHY
FOG AND LOWER CEILINGS MAY BE POSSIBLE ONCE AGAIN SUNDAY NIGHT.
WINDS WILL BE LIGHT OUT OF THE SOUTHWEST TODAY, AND THEN LIGHT
OUT OF THE EAST TO NORTHEAST ON SUNDAY.
PREVAILING VFR CONDITIONS ARE LIKELY MONDAY THROUGH THURSDAY
NEXT WEEK. LIGHT EASTERLY WINDS WILL BECOME SOUTHERLY TUESDAY
AND WEDNESDAY BEFORE TURNING SOUTHWESTERLY LATE WEEK.
MARINE
LIGHT AND VARIABLE WINDS ARE EXPECTED OVER THE WATERS TODAY.
WINDS TURN LIGHT OUT OF THE EAST TO NORTHEAST ON SUNDAY. SHOWERS
AND THUNDERSTORMS ARE EXPECTED ON AND OFF OVER THE COURSE OF
THE WEEKEND, WITH SPECIAL MARINE WARNINGS POSSIBLE.
SUB-SCA LEVEL EAST TO SOUTHEAST FLOW IS EXPECTED MONDAY AS HIGH
PRESSURE BUILDS INTO THE REGION. WINDS WILL BECOME MORE
SOUTHERLY TUESDAY BEFORE TURNING SOUTHWESTERLY MID TO LATE
WEEKEND. SCA CONDITIONS WILL BE TIED TO CHANNELING MAINLY OVER
THE CHESAPEAKE BAY TUESDAY AFTERNOON AND EVENING, AND AGAIN
WEDNESDAY AFTERNOON AND EVENING. THIS IS ESPECIALLY TRUE OVER
THE MIDDLE AND OPEN WATERS WHERE BRIEF SCA CONDITIONS ARE
POSSIBLE DURING THIS TIME.
CLIMATE
THERE IS A SIGNIFICANT HEAT RISK NEXT WEEK. THE NUMBERS BELOW
AREN'T A FORECAST, BUT RATHER A REFERENCE FOR HISTORICAL CONTEXT
FOR COMPARISON. LATEST FORECAST: WEATHER.GOV/LWX.
==================================================================
*** ALL-TIME RECORD HIGHS ***
==================================================================
BALTIMORE 107 (SET ON JUL 10, 1936)
WASHINGTON 106 (SET ON JUL 20, 1930 + AUG 06, 1918)
STERLING-DULLES AIRPORT 105 (SET ON JUL 22, 2011)
BALTIMORE DOWNTOWN 108 (SET ON JUL 07, 2012 + JUL 22, 2011)
ANNAPOLIS 106 (SET ON AUG 06, 1918)
HAGERSTOWN 105 (SET ON JUL 14, 1954)
MARTINSBURG 112 (SET ON JUL 11, 1936)
CHARLOTTESVILLE 107 (SET ON SEP 07, 1954 + 3 OTHER TIMES)
==================================================================
*** ALL-TIME RECORD WARM LOWS ***
==================================================================
BALTIMORE 83 (SET ON AUG 05, 1930 + 2 OTHER TIMES)
WASHINGTON 84 (SET ON JUL 24, 2011 + 2 OTHER TIMES)
STERLING-DULLES AIRPORT 79 (SET ON AUG 08, 2007)
BALTIMORE DOWNTOWN 88 (SET ON JUL 02, 2011 AND JUL 10, 1993)
ANNAPOLIS 92 (SET ON JUL 07, 1994)
HAGERSTOWN 86 (SET ON JUN 15, 1899)
MARTINSBURG 86 (SET ON JUL 21, 1930)
CHARLOTTESVILLE 85 (SET ON AUG 07, 1918)
==================================================================
*** JULY MONTHLY RECORD HIGHS ***
==================================================================
BALTIMORE 107 (SET ON JUL 10, 1936)
WASHINGTON 106 (SET ON JUL 20, 1930)
STERLING-DULLES AIRPORT 105 (SET ON JUL 22, 2011)
BALTIMORE DOWNTOWN 108 (SET ON JUL 07, 2012 + JUL 22, 2011)
ANNAPOLIS 105 (SET ON JUL 21, 1930 + JUL 02, 1901)
HAGERSTOWN 105 (SET ON JUL 14, 1954)
MARTINSBURG 112 (SET ON JUL 11, 1936)
CHARLOTTESVILLE 107 (SET ON JUL 10, 1936 + JUL 20, 1930)
==================================================================
*** JULY MONTHLY RECORD WARM LOWS ***
==================================================================
BALTIMORE 83 (SET ON JUL 21, 1930)
WASHINGTON 84 (SET ON JUL 24, 2011 + 2 OTHER TIMES)
STERLING-DULLES AIRPORT 78 (SET ON JUL 24, 2010 + JUL 08, 2010)
BALTIMORE DOWNTOWN 88 (SET ON JUL 22, 2011 + JUL 10, 1993)
ANNAPOLIS 92 (SET ON JUL 07, 1994)
HAGERSTOWN 83 (SET ON JUL 24, 2010)
MARTINSBURG 86 (SET ON JUL 21, 1930)
CHARLOTTESVILLE 84 (SET ON JUL 22, 1930)
==================================================================
*** DAILY RECORD HIGHS | WARM LOWS ***
VALID: JUL 01
==================================================================
BALTIMORE 103 (1901) | 80 (1933 + 1901)
WASHINGTON 102 (1901) | 79 (1977)
STERLING-DULLES AIRPORT 96 (2012) | 72 (2017 + 3)
BALTIMORE DOWNTOWN 101 (2012) | 82 (2012)
ANNAPOLIS 103 (1901) | 79 (1945 + 1901)
HAGERSTOWN 100 (1901) | 74 (2017 + 1977)
MARTINSBURG 102 (1933) | 74 (1933)
CHARLOTTESVILLE 101 (2012 + 1945) | 78 (1901)
==================================================================
*** DAILY RECORD HIGHS | WARM LOWS ***
VALID: JUL 02
==================================================================
BALTIMORE 103 (1901) | 80 (1901)
WASHINGTON 101 (1898) | 79 (2012 + 1872)
STERLING-DULLES AIRPORT 98 (1966) | 75 (2022)
BALTIMORE DOWNTOWN 102 (1966) | 84 (2002)
ANNAPOLIS 105 (1901) | 80 (1901)
HAGERSTOWN 100 (1966) | 74 (2018 + 1901)
MARTINSBURG 102 (1933 + 1931) | 75 (1933 + 1901)
CHARLOTTESVILLE 100 (1954) | 76 (1910)
==================================================================
*** DAILY RECORD HIGHS | WARM LOWS ***
VALID: JUL 03
==================================================================
BALTIMORE 104 (1898) | 80 (1898)
WASHINGTON 101 (1966 + 2) | 80 (2018)
STERLING-DULLES AIRPORT 103 (1966) | 73 (2018 + 2)
BALTIMORE DOWNTOWN 102 (1997) | 82 (2018 + 1983)
ANNAPOLIS 100 (1901) | 84 (1896)
HAGERSTOWN 102 (1966) | 76 (2002)
MARTINSBURG 102 (1941 + 1911) | 74 (1980)
CHARLOTTESVILLE 100 (1966 + 1954) | 79 (1911)
PERIOD OF RECORD (POR) CONTEXT...
AREA (OBS SITE) RECORDS SINCE
------------------------------------------------------------------
BALTIMORE (BWI) JAN 1872
WASHINGTON (DCA) JUL 1872
STERLING-DULLES AIRPORT (IAD) JAN 1960
BALTIMORE DOWNTOWN (DMH) JUL 1950
ANNAPOLIS (NAK) JAN 1894
HAGERSTOWN (HGR) JAN 1899
MARTINSBURG (MRB) JAN 1891
CHARLOTTESVILLE (CHO) JAN 1893
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...DHOF/KJP/EST
AVIATION...DHOF/KJP/EST
MARINE...DHOF/KJP/EST
CLIMATE...DHOF
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