000
FXUS61 KLWX 200706
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
306 AM EDT SAT MAR 20 2010
.SYNOPSIS...
HIGH PRESSURE DOMINATES...WITH TRANQUIL AND MILD WEATHER ACROSS
THE REGION THROUGH SUNDAY. A STRONG UPPER LEVEL DISTURBANCE AND
ITS ASSOCIATED COLD FRONT ARE EXPECTED TO IMPACT THE REGION
SUNDAY NIGHT THROUGH MONDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
IN FOR MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIPRES GRADUALLY SLIDES OF THE ATLC SEABOARD TNGT...BUT IT RMNS
THE DOMINANT WEATHER FEATURE THRU TNGT. WITH CNTR OF HIGH E OF
REGION...LGT NW WINDS THIS MRNG WILL GRADUALLY TRANSITION TO SW
THIS AFTN. THIS WILL BRING MODEST DEWPOINT RISES TO THE REGION...
THOUGH SKIES SHUD BE GENLY SUNNY XPCT FOR SOME HIGH CLOUDS
STREAMING OVR FROM THE W. KEPT MAXIMA WITHIN A COUPLE DEGREES OF
YDA...AS INCRG MOISTURE AND SOME CIRRUS SHUD COUNTERACT EFFECTS OF
WEAK WAA. WEAKENING CDFNT APPROACHES FROM THE NW THIS AFTN...BUT
SHUD HAVE NO IMPACT ON CWA. HI TEMPS XPCD TO REACH L/M70S MOST
LOCATIONS... WITH 60S ACRS HIGHER TERRAIN ALONG AND W OF BLUE
RIDGE.
INCRG SLY FLOW AND MOISTURE XPCD TNGT. MID/HIGH CLOUDS WILL ALSO
INCR OVNGT AS SWLY FLOW ALOFT BRINGS OVER DEBRIS FROM STRENGTHENING
STORM SYSTEM ACRS SRN PLAINS. TEMPS SHUD BE WARMER THAN PREV
NGTS...MINIMA IN THE 40S...WITH L50S ACRS URBAN CENTERS.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A WK CDFNT WL BE STALLED EITHER ACRS CWFA OR JUST N OF IT ON SUN.
BUT...W/O MUCH LLVL MSTR OR MID LVL FORCING TO WORK OFF OF...THINK
IT/LL JUST MARK A SWATH OF CLDCVR. THE ZN IN QSTN CLEARLY CONTAINS A
THERMAL GRADIENT ON CRRNT SFC ANALY...BUT GDNC STILL SUGGESTS
ANAFRONTAL STRUCTURE. COUPLED W/ A PERSISTENT SERN CONUS RDGG AND
CUTOFF UPR LOW OVR THE LWR MD VLY...WHICH SHUD SUPPORT A SLOER
SYSTEM EVOLUTION...ITS HARD TO SEE MUCH PCPN LCLLY DURING THE DAY ON
SUNDAY. HV CONSEQUENTLY BACKED OFF ON POPS AND BUMPED MAXT UP IN
SPITE OF CLDS.
SLY H10-8 WNDS INCR SUN NGT...MARKING INCRSD DEWPT ADVCTN/HIER THTE
AIR. THE UPWD TICK IN MSTR/UPGLIDE WL SUPPORT PCPN...SPCLY TWD DAWN
IN THE MTNS AND SHEN VLY AS CLSD LOW WOBBLES CLOSER. THESE AREAS W/
FEATURE LKLY/CAT POPS. OUTSIDE OF AREAS W/ HIER PCPN CHCS...MIN-T
MAY NOT DROP BLO 50F...NOT TOO FAR RMVD FROM NRML MAXT.
MON WL FEATURE BEST FORCING...AND PERHAPS A PINCH OF INSTBY AS WELL.
ANY THUNDER SHUD BE ELEVATED AND LMTD...BUT CANNOT DISCOUNT IT IN
LIGHT OF SREFS AND INDICES OFF MDL SNDGS. PLUS...PWAT NEAR AN INCH
WL MAKE SOME HVY RAINERS A PSBLTY. ACTIONS ATTM INCL PLACING MDT
SHRA /DEF POPS/ IN GRIDS DURING THE MRNG /COINCIDENT W/ THTE RDG
AXIS...THEN KEEP CHC TSRA DURING AFTN SUPPORTED BY LAPSE RATES INVOF
CLSD LOW.
SFC FEATURES APPEAR TO BE OCCLUDED...BUT H5 LOW WL GRDLY MIGRATE S
OF VA MON NGT-TUE. WL KEEP PRVS FCST OF DECREASING POPS THRU MON NGT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AFTER A CLOUDY-COOL TUE - SINCE THE UPPER LOW WILL TAKE ALL-DAY TO
COMPLETELY EXIT OFF THE COAST...HIGH PRESSURE WILL AGAIN BUILD
ACROSS THE SOUTHEAST AND UP THE ERN SEABOARD. ANOTHER COMPLEX
SCENARIO WILL THEN TAKE SHAPE BACK TO THE WEST. A FAIRLY SIMILAR
UPPER LOW FEATURE WILL CROSS THE SAME AREAS OF THE ROCKIES/SRN
PLAINS WED/THU OF NEXT WEEK...BUT NOT W/ THE SAME UPPER SUPPORT AT
THE BEGINNING - WHICH WOULD LIKELY MEAN NOT AS FAR OF A TREK TO THE
SOUTH AS THE CURRENT SYSTEM.
RAIN CHANCES WILL BEGIN TO INCREASE TOWARD THE END OF THE WORK
WEEK...THOUGH A MORE ACCURATE DEPICTION FOR NEXT WEEKEND STILL
UNCERTAIN AND WILL DEPEND OF THE EFFECTS A STRONG UPPER WAVE THAT
WILL SWINGING AROUND THE SRN HUDSON BAY/NRN GREAT LAKES REGION AT
THE TIME.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
MOSTLY CLR SKIES AND LGT WINDS XPCD THRU TNGT...WITH NO VSBY/CIG
RESTRICTIONS. CIRRUS AOA 20KFT XPCD...GRADUALLY INCRG LT THIS AFTN
AND EVE. MID LVL STRATUS BEGINS TO PUSH IN FROM THE W TMRW. WNW
WINDS AOB 10 KT ERY TDA BCM SLY LATE AFTN AND TNGT.
NO FLGT RESTRICTIONS XPCTD SUN...BUT CONDS WL DETERIORATE SUN
NGT-MON AS STORM SYSTEM APPROACHES. MVFR SHUD BE WDSPD AND OCNL IFR
PSBL INTO MON NGT. WORST CONDS MON NGT AS ELY WNDS MAY BRING IN LLVL
STRATUS. WL NEED TO BURN THIS OFF TUE IN NW FLOW. ONCE WE DO...FAIR
WX INTO MIDWEEK.
&&
.MARINE...
DRY CONDS WITH SLY WINDS INCRG TO NEAR 10 KT THIS AFTN AS HIPRES
SLIDES E OF WATERS. SLY WINDS MAINTAIN SIMILAR SPEEDS TNGT...AS
STORM SYSTEM BEGINS TO APPROACH FROM THE SW.
SLY FLOW ARND 10 KT SUN...BUT THEN WNDS PICK UP A LTL SUN NGT...
AND MORE NOTABLY ON MON. SCA PSBL MON IN ADVC OF LOPRES...AND AGN
TUE IN NW FLOW ON BACK SIDE OF SAME SYSTEM.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SBK/HTS
NEAR TERM...SBK
SHORT TERM...HTS
LONG TERM...GMS
AVIATION...SBK/HTS
MARINE...SBK/HTS
