Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 250758
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
358 AM EDT MON APR 25 2016

.SYNOPSIS...HIGH PRESSURE WILL MOVE FURTHER OFFSHORE THROUGH
TUESDAY. A COLD FRONT WILL CROSS THE AREA TUESDAY EVENING. WEAK
HIGH PRESSURE BUILDS TUESDAY NIGHT THROUGH EARLY THURSDAY. ANOTHER
COLD FRONT IS EXPECTED THURSDAY NIGHT. HIGH PRESSURE BUILDS FOR
THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...DEVELOPING S TO SW FLOW WILL USHER
IN WARMER TEMPS TODAY WITH 80S IN MANY PLACES XCPT 70S NCNTRL AND
NORTHEAST MD AND THE HIGHER ELEVS. A FEW POP UP SHOWERS POSSIBLE
OVER THE POTOMAC HIGHLANDS AND SRN BLUE RIDGE MTNS. ONLY TRACE
AMTS EXPECTED. MILD AND INCREASINGLY HUMID TONIGHT WITH LOWS UPPER
50S TO LOW 60S. A FEW SHOWERS COULD MAKE IT TO THE NCNTRL MD
COUNTIES TOWARD DAYBREAK TUE AS CDFNT MOVES ACROSS PA.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...WARMER ON TUE AS SW
FLOW STRENGTHENS AHEAD OF A CDFNT. TEMPS EXPECTED IN THE MID 80S
AND MAY APPROACH 90F IF THE WARMER ECMWF GUIDANCE VERIFIES. BEST
MOISTURE WILL BE OVER THE NRN HALF OF THE FCST AREA WHERE SHOWERS
AND T-STORMS APPEAR DEFINITE AS CDFNT CROSSES THE AREA. 0-6KM BULK
SHEAR LOOKS STRONG AROUND 40-KT AND CAPE VALUES INCREASE TO NEAR
1000 J/KG. MARGINAL RISK FOR SEVERE PER SPC DY2 OTLK APPEARS
REASONABLE GIVEN LACK OF DEEP MOISTURE (I.E. DEWPOINTS LESS THAN
60F) AND STRONG INSTABILITY. GUSTY WINDS WOULD BE THE PRIMARY
THREAT GIVEN DEEPLY MIXED BDRY LAYER. CDFNT CROSSES THE AREA TUE
EVENING WITH SHOWERS AND T-STORMS DIMINISHING. STRATUS CLOUDS FCST
TO DEVELOP LATE TUE NIGHT ON NORTHEAST WINDS AS COOL WEDGE
DEVELOPS/STRENGTHENS.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...THE BACK DOOR FRONT WILL SETTLE
OVER THE REGION WEDNESDAY AND WEDNESDAY NIGHT WITH ZONAL FLOW
ALOFT. PASSING WEAK DISTURBANCES WILL KEEP SHOWERS A
POSSIBILITY...ESPECIALLY SOUTHERN PARTS OF THE AREA. TEMPS MAY
DEPEND ON FRONTAL POSITION AND AMOUNT OF PRECIP...BUT OVERALL
EXPECT BELOW NORMAL DURING THE DAY WITH A MUTED DIURNAL TREND.

SFC WAVE OF LOW PRESSURE WILL APPROACH THURSDAY AND INCREASE THE
CHANCE FOR SHOWERS AREA-WIDE. WHILE A FEW RUMBLES OF THUNDER COULD
OCCUR...THE WEDGE OF STABLE HIGH PRESSURE COULD HELP LIMIT INSTBY.
MID/UPPER SHORTWAVE TROUGH WILL NOT PASS THROUGH UNTIL
FRIDAY...MAINTAINING SMALLER CHANCES FOR SHOWERS.

FRIDAY NIGHT THROUGH SATURDAY NIGHT WILL HAVE A BETTER CHANCE OF
BEING DRY AS HIGH PRESSURE BUILDS FROM THE NORTH AND DEEPENING LOW
OVER THE PLAINS PROMOTES DOWNSTREAM RIDGING. THE LOW WILL MOVE
TOWARD THE MS VALLEY SUNDAY...WITH GOOD MODEL AGREEMENT ON
OVERRUNING GULF MOISTURE BRINGING ADDITIONAL RAIN.

EXPECT FAIRLY SEASONABLE TEMPS FOR THE LATTER PART OF THE WEEK AND
WEEKEND.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...LIGHT S TO SW WINDS TODAY
STRENGTHENING TUE WITH GUSTS 20-25 KT. SHOWERS AND T-STORMS LIKELY
TUE XCPT SCT AT KCHO. CDFNT CROSSES THE AREA TUE EVENING WITH
WINDS SHIFTING TO NE. STRATUS CLOUDS FCST TO DEVELOP LATE TUE
NIGHT AS WEDGE DEVELOPS.

MVFR (PERHAPS LOCALLY IFR) CIGS WILL BE POSSIBLE AT TIMES WEDNESDAY
THROUGH FRIDAY AS A FRONT LINGERS OVER THE AREA...ALTHOUGH SPECIFICS
ARE UNCERTAIN ATTM. BEST CHANCE FOR RAIN WITH SUB-VFR VSBYS WILL BE
THURSDAY.

&&

.MARINE...BORDERLINE SCA CONDITIONS THROUGH THIS MORNING. MORE
SOLID SCA CONDITIONS TONIGHT AND TUE AS PRES GRADIENT TIGHTENS.
T-STORMS LIKELY TUE AFTERNOON WHICH MAY PRODUCE GALE FORCE
CONVECTIVE GUSTS AND REQUIRE SPECIAL MARINE WARNINGS.

NE TO E WINDS WILL PREVAIL WEDNESDAY THROUGH FRIDAY AS A FRONT
LINGERS OVER THE REGION. ATTM IT APPEARS WIND SPEEDS WILL REMAIN
BELOW SCA CRITERIA.

&&

.FIRE WEATHER...S TO SW WINDS 10 MPH OR LESS STRENGTHENING TO 15
TO 20 MPH TUE. MIN RH`S WILL BE AROUND 30 PERCENT TODAY BUT SOME
GUIDANCE LIKE THE ECMWF SUGGESTS LOWER RH`S IN THE 20S. STRONGER
WINDS TUE MAY REQUIRE AN SPS FOR THE SOUTHERN HALF IF MOISTURE
DOESN`T RECOVER SIGNIFICANTLY.

&&

.TIDES/COASTAL FLOODING...WATER LEVELS CONTINUE TO RISE AT
ANNAPOLIS AND MAY HIT MINOR COASTAL FLOODING THRESHOLD AT HIGH
TIDE AT 8AM TODAY. WILL CONTINUE TO MONITOR CLOSELY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
     ANZ531>534-537-539>543.
     SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT TUESDAY FOR ANZ530-
     531-535-536-538-539.
     SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT
     TUESDAY FOR ANZ532>534-537-540>543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...ADS
AVIATION...ADS/LFR
MARINE...ADS/LFR
FIRE WEATHER...LFR
TIDES/COASTAL FLOODING...LFR



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