National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 301858
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
158 PM EST FRI JAN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR THE FIRST HALF OF
THE WEEKEND. LOW PRESSURE WILL IMPACT THE AREA LATE SUNDAY INTO
MONDAY. HIGH PRESSURE WILL RETURN FOR THE FIRST HALF OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
E OF THE MTNS TEMPS HV BEEN WARMING FASTER THAN XPCTD...AND HV
BEEN ADJUSTED UPWARDS. STLT SHOWS WVS OF CLDS CONT TO STREAM INTO
THE AREA FM THE NW. STEEP LOW LVL LAPSE RATES ON IAD 12Z SNDG - WE
HV ALREADY SEEN ONE BAND OF SNSH MOVE THRU THE AREA. SUSPECT THAT
WE SEE MORE THIS AFTN.

HIGH PRES BLDG INTO THE AREA - THE STEEP LO LVL TEMP GRAD WL ALSO
HELP TRANSLATE GUSTY WINDS TO SFC. WIND ADVSRY IS IN EFFECT FOR
MAJORITY OF THE FCST AREA.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
SFC HIGH PRESSURE PUSHES EAST OVER THE REGION IN THE WAKE OF THE
COLD FRONT AS RIDGING BUILDS IN ALOFT. MAINLY DRY CONDITIONS TONIGHT
THRU SAT NIGHT WITH THE EXCEPTION OF ANY LINGERING LIGHT UPSLOPING
SNOW SHOWERS FIRST HALF OF TONIGHT. SUBSIDENCE ALOFT WILL RESULT IN
MOSTLY CLEAR CONDITIONS TONIGHT...AND SUNNY CONDITIONS FOR SAT.

THE MAIN CONCERN DURING THIS TIME FRAME WILL BE THE WELL BELOW
NORMAL TEMPS BEING USHERED IN AS 850MB TEMPS DIP BELOW -10 DEGREES
CELSIUS. USING A BLEND OF ADJMET/MOSGUIDE...TEMPS TONIGHT EXPECTED
TO DROP INTO THE TEENS EVERYWHERE EXCEPT POTOMAC HIGHLANDS...WHICH
SHOULD SEE LOWS INTO THE SINGLE DIGITS. THESE TEMPS COMBINED WITH
THE ON GOING NW FLOW WILL PRODUCE WIND CHILLS INTO THE SINGLE
DIGITS. THE POTENTIAL EXISTS FOR NEEDING A WIND CHILL ADVISORY OVER
THE FAR WESTERN PORTIONS OF THE POTOMAC HIGHLANDS WITH WIND CHILLS
DROPPING TO AROUND -12 DEGREES. HOWEVER...HAVE HELD OFF FOR ANY
ISSUANCE AT THIS TIME WITH THE VALUES BEING BORDERLINE WITH THE
CRITERIA AND IT BEING MAINLY AFTER 06Z TONIGHT. ELSEWHERE...THOUGH
IT WILL BE VERY COLD...WIND CHILLS VALUES ARE EXPECTED TO REMAIN ABV
CRITERIA LVLS.

BY SATURDAY...WILL SEE GRADUAL WARMING AS THE HIGH NUDGES ACROSS THE
AREA...WITH RETURN FLOW SETTING UP AND INJECTING IN WARMER AIR.
DESPITE THE WARMING...TEMPS STILL EXPECTED TO REMAIN BELOW NORMAL
THRU AT LEAST SAT NIGHT. 00Z MODEL SUITE IN PRETTY GOOD AGREEMENT OF
ANY PCPN MOVING INTO THE REGION WITH THE NEXT LOW PRESSURE SYSTEM
HOLDING OFF TILL AFTER 12Z SUNDAY AND HAVE THUS A DRY FORECAST THRU
THIS TIME PERIOD.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
MDLS ARE TRACKING THE LOW PRES AREA SUN NGT/MON ACROSS THE CWA.
ATTM THE BEST CHC FOR ACUMULATING SNOWS LOOKS TO BE ALONG THE M-D LN.

NEXT WEEK WL START COLD AS THE CSTL LOW STRENGTHENS...DRAGGING
DOWN COLD AIR. H8 TEMPS SHUD BE DROPPING TO -10 TO -14C. AT THAT
RATE MON-TUE MAXT WL HV TROUBLE RISING ABV FRZG...AND MIN-T MAY
DIP BELOW 0 DEGF ACRS NRN MD AND IN THE PTMC HIGHLANDS.

GFS SUGGESTING THAT ANOTHER SRN STREAM LOW WL FLLW MIDWEEK HIPRES
FOR A POTL STORMY THU. ITS STILL TBD IF WE WL RECEIVE THE LOW OR IT
WL PASS S OF CWFA. WL BE KEEPING POPS LOW AS THERES A LOT OF WX TO
GET THROUGH FIRST.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH SAT.

MAIN CONCERN TODAY STRONG NW FLOW. GUSTS START TIME +/- 1-2
HRS...GENERALLY IN THE 20S THIS MORNING...THEN INCREASING 30-40
KTS THIS AFTN/EVENING. WINDS WILL GRADUALLY DIMINISH
TONIGHT...WITH GUSTS PSBL THOUGH THROUGH THE NIGHT. KCHO COULD SEE
GUSTS ENDING AS EARLY AS 06Z. ISO SNOW SHOWER PSBL KMRB BUT TOO
LOW CONFIDENCE TO INCLUDE...ESP WITH LITTLE IMPACT TO CONDITIONS.

DECREASING WNW FLOW SAT WITH WINDS BCMG W SAT NIGHT. PSBL LOWERING
CIGS LATE SAT NIGHT AS THE NEXT LOW PRESSURE SYSTEM APPROACHES.

FLGT RESTRICTIONS APLENTY SUN AS LOPRES CROSSES TERMINALS. THE
AFTN-NIGHT TIME HRS SHUD BE MOST AFFECTED. PTYPE ISSUES EXIST. ITS
NO LONGER A CLEAR-CUT SNOW EVENT. THE LOW WL BE PULLING OFFSHORE
MON. CONDS WL IMPRV THRU THE DAY...BUT SHUD HV SOME STRONG NW WIND
GUSTS.

VFR TUE UNDER HIPRES.

&&

.MARINE...
GALE WARNING IN EFFECT FOR THRU TONIGHT. COULD SEE LINGERING
GALES PAST DAYBREAK SAT MORNING...BUT HAVE HELD AT 09Z TO ACCOUNT
FOR UNCERTAINTY THEREAFTER. HIGH CONFIDENCE SCA CONDITIONS WILL
SET IN SAT MORNING FOR CHESAPEAKE BAY...AND PSBL OVER THE TIDAL
POTOMAC. SUB-SCA CONDITIONS EVERYWHERE FOR SAT NIGHT.

LOPRES APPRCHS WATERS SUN DAY AND CROSSES SUN NGT. TRACK OF LOW WL
PERMIT A MIXED BAG OF PTYPES AT NIGHT BEFORE CHGG BACK TO SNOW UPON
EXIT MON. ALSO ON MON SHUD BE STIFF NW WINDS AS THE STORM
STRENGTHENS AS IT PULLS AWAY. AT LEAST SCA PSBL. WUDNT COMPLETELY
RULE OUT GLW...CONTINGENT UPON DETAILS THAT ARE STILL A LTL MURKY.
HIPRES WL RETURN BY TUE.

&&

.TIDES/COASTAL FLOODING...
WINDS TURNED NW BHD A COLD FRONT. THIS WILL SUPPORT BLOW OUT TIDES.
THEREFORE...WATER LEVELS XPCTD TO RETURN TO NORMAL TONIGHT.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR DCZ001.
MD...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MDZ003>006-011-
     013-014-016>018-501>508.
VA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ025>031-040-
     051>055-057-501>508.
WV...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR WVZ050>053-055-
     501>506.
MARINE...GALE WARNING UNTIL 4 AM EST SATURDAY FOR ANZ530>543.

&&

$$
UPDATE...WOODY!