Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 020908 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 408 AM EST TUE FEB 2 2016 .SYNOPSIS... HIGH PRESSURE OVER LAKE ERIE BUILDS INTO THE AREA TODAY. A COLD FRONT WILL MOVE THROUGH THE MID ATLANTIC STATES WEDNESDAY AFTERNOON BRINGING WIDESPREAD RAIN. HIGH PRESSURE BUILDS IN FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DON`T WANT THIS TO GET LOST IN THE MULTIPLE SXNS OF THIS DSCN - INTERESTING TO LOOK AT AREA HYDROGRAPHS. STRMS/CRKS SHOWED SHARP RISES DURG MON AFTN BUT ARE NOW FALLING. RVRS ARE NOW ON THE RISE BUT ARE STILL SVRL FT BLO FLD STG. THESE RISES APPEAR TO BE SLOWING. HIGH PRES OVR LAKE HURON/ERIE WL BLD OVR THE E CST TDA. A FEW SPOTS HV DVLPD FOG OVRNGT. GIVEN THE LGT WIND FLOW AREA WL XPRNC TDA WHERE FOG HAS DVLPD IT MAY BE HARD TO DISLODGE...BUT IT IS QUITE LOCALIZED. HIGHS TO RANGE FM THE M50S CENTRAL SHEN VLLY TO MU40S ALONG THE PA BRDR. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... CD FNT WL BE MOVG INTO TN VLLY TNGT WHILE HIGH PRES MOVES OVR ATLC CANADA. THIS COMBO WL LKLY SPELL FOR A WARM NGT W/ LOWS PRIMARILY IN THE LM40S. FOG DVLPMNT WL BE PSBL AGN TNGT. PCPN CHCS WL BEGIN AFTR MDNGT IN THE W...WORKING THEIR WAY E BY MRNG. WED WL BE ANOTHER VERY INTERESTING DAY AS A CD FNT CROSSES THE RGN DURG THE MIDDDAY HRS. HV PUSHED TEMPS UP AS I BLV WAA COULD BE FAIRLY STRONG EVEN THO 3/4-1" OF RA WL BE PSBL. ALSO BLV WINDS ABV 2500 FT COULD GUST INTO THE 30-40 MPH RANGE ON STRONG SRLY FLOW. SEE HYDRO SXN BLO FOR CONCERNS ABT MELTING OF RMDR OF SNOWPACK/RA/ STREAM/CRK/RVR RISES. LWR SRN MD IS ALSO OUTLOOKED IN A MRGNL RISK. RDR OPERATOR WL HV TO BE LOOKING AT ANY STORMS THAT TRACK NE OUT OF SRN VA. WED LOOKS TO BE WARM W/ HIGHS IN THE 60S. SEE CLI SXN BLO - THE DAYS ON BOTH SIDES OF THE 3RD HV RECORD HIGHS IN THE 70S FOR ALL 3 MAJOR AIRPORTS...BUT THE 3RD`S ARE IN THE M60S. && .LONG TERM /THURSDAY THROUGH MONDAY/...
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NORTHWEST FLOW CONTINUES BEHIND DEPARTING FRONTAL SYSTEM THURSDAY NIGHT. THERE MAY BE A FEW LINGERING UPSLOPE SNOW SHOWERS ALONG THE ALLEGHENY FRONT...BUT OVERALL DRY AND MOSTLY CLEAR CONDITIONS. HIGH PRESSURE THEN BUILDS IN OVERHEAD DELIVERING MOSTLY SUNNY SKIES AND DRY WEATHER FOR FRIDAY AND SATURDAY. TEMPERATURES ON FRIDAY NEAR TO SLIGHTLY BELOW NORMAL (30S/40S)...MODERATING TO SLIGHTLY ABOVE NORMAL ON SATURDAY (40S TO NEAR 50F). A NORTHERN STREAM COLD FRONT WILL SKIRT OFF TO THE NORTH ON SUNDAY WITH LITTLE TO NO IMPACT TO THE REGION. AS A LARGE SCALE RIDGE BUILDS ON THE WEST COAST...A FULL LATITUDE TROUGH WILL THEN CARVE OUT ACROSS THE EAST IN THE BEGINNING OF NEXT WEEK...WITH POTENTIAL FOR DEVELOPING COASTAL LOW. TEMPERATURES WILL START MILD ON SUNDAY (40S/50S)...BECOMING COLDER INTO NEXT WEEK.
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&& .AVIATION /09Z TUESDAY THROUGH SATURDAY/...
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MRB HAS DROPPED TO IFR IN FG. VFR CONDS ELSEWHERE. W/ LGT WINDS THIS MRNG MRB MAY TAKE SOME TIME TI IMPRV. ELSEWHERE ALL SITES SHOULD BE VFR. INCRSG CLD CVR TNGT. RA WED AHD OF A STRONG CD FNT COULD DROP CIGS INTO IFR RNG. FOG DVLPMNT WL ALSO BE PSBL BOTH TUE NGT AND WED AS WARM MOIST AIR FLOWS OVR SNOW CVRD GRND. VFR EXPECTED UNDER HIGH PRESSURE FOR THE FRIDAY AND INTO THE WEEKEND.
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&& .MARINE...
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SCA HAS BEEN ISSUED FOR WED FOR ALL WATERS IN STRONG SRLY FLOW AHD OF A CD FNT. ISOLD TSTMS WL BE PSBL WED...MAINLY IN THE AFTN AND MAINLY OVR THE LWR PTMC/WIDER SXN OF THE MD PART OF THE CHES BAY. NORTHWESTERLY FLOW BEHIND DEPARTING FRONTAL SYSTEM WILL LIKELY BRING SCA CONDITIONS THURSDAY NIGHT INTO FRIDAY...WEAKENING AS HIGH PRESSURE BUILDS INTO THE AREA LATER FRIDAY AND SATURDAY.
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&& .HYDROLOGY... MON MORNING READING SHOWED ANOTHER HALF INCH OF LIQUID EQUIV LOST BETWEEN FRIDAY AND MONDAY...NOW DOWN TO 1.6 INCHES. STEADY MELTING IS CONTINUING DUE TO THE WARM TEMPERATURES AND MILD DEWPOINTS. THANKS TO THE DRIFTS...THERE ARE SPOTS WITH A LOT OF SNOW COVER AND SNOW WATER...WHILE OTHER SPOTS HAVE GONE TOTALLY BARE. AREAS WHERE THE SNOW DEPTH IS STILL AROUND A FOOT LIKELY HAVE ABOUT 3 INCHES OF WATER IN THAT SNOW. MELTING HAS SHOWN UP ON THE RIVERS IN THE POTOMAC HIGHLANDS AND RAPPAHANNOCK/OCCOQUAN BASINS...NOT SO MUCH FURTHER NORTH. A SLOW BUT STEADY MELT CONTINUES TODAY...BUT NOT AS MUCH AS MONDAY SINCE IT WILL BE COOLER. THE PERIOD OF HIGHEST POTENTIAL CONCERN REMAINS WEDNESDAY INTO THURSDAY. TEMPERATURES ARE FORECAST TO WARM INTO THE 60S ALMOST EVERYWHERE EAST OF THE POTOMAC HIGHLANDS WEDNESDAY...WITH RAIN AND LIKELY A MELT OF MOST IF NOT ALL OF THE REMAINING SNOW WATER... ESPECIALLY EAST OF THE BLUE RIDGE. ULTIMATELY...THE FLOOD POTENTIAL WILL BE DEPENDENT ON HOW MUCH SNOW WATER REMAINS BY THEN...AND HOW MUCH RAIN ACTUALLY FALLS. CURRENT EXPECTATIONS ARE FOR A HALF TO THREE-QUARTERS OF AN INCH OF RAIN IN MOST AREAS...POSSIBLY UP TO AN INCH IN NERN MD AND A FEW OTHER LOCALIZED SPOTS. THIS YIELDS POTENTIAL FOR SMALL-STREAM FLOODING WEDNESDAY... ESPECIALLY EAST OF THE BLUE RIDGE...AND URBAN FLOODING WEDNESDAY AFTERNOON ESPECIALLY WHERE DRAINS ARE SNOW-BLOCKED. NOT ENOUGH CONFIDENCE YET TO RAISE AN AREAL FLOOD WATCH. RIVER FLOOD POTENTIAL IS WEDNESDAY NIGHT THROUGH THURSDAY...POSSIBLY LASTING INTO FRIDAY ON THE MAINSTEM POTOMAC. THE HIGHEST POTENTIAL IS GENERALLY BETWEEN SPRINGFIELD AND WASHINGTON DC ON THE POTOMAC... AND THE LARGER TRIBUTARIES THAT FLOW INTO THE POTOMAC...SUCH AS THE OPEQUON AND MONOCACY AND MAINSTEM SHENANDOAH. HOWEVER...IT IS IMPORTANT TO NOTE THAT RIGHT NOW THE MOST LIKELY SCENARIO FOR MOST AREAS WHERE A THREAT EXISTS IS FOR MINOR TO LOW-END MODERATE FLOODING ONLY. && .TIDES/COASTAL FLOODING...
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WATER LEVELS WILL BE GRADUALLY RISING IN ONSHORE FLOW TUESDAY AND SOUTHERLY FLOW WEDNESDAY. TIDES WILL LIKELY EXCEED MINOR FLOODING THRESHOLDS AT HAVRE DE GRACE AND BOWLEYS QUARTERS LATE WEDNESDAY. BALTIMORE AND ANNAPOLIS WILL BE THREATENING ACTION STAGE DURING THIS CYCLE AS WELL. WILL CONTINUE TO MONITOR.
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&& .CLIMATE... RECORDS HIGHS FOR WED: FEB 3RD IS SORT OF "LOW HANGING FRUIT" AS RECORDS MAXES THAT DAY ARE COLDER THAN SURROUNDING DAYS. DCA: 65 SET IN 1927 BWI: 66 SET IN 1932 IAD: 66 SET IN 1991 && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM TO 6 PM EST WEDNESDAY FOR ANZ530>543. && $$ PRODUCTS...WOODY!/MJM/JCE

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