FXUS61 KLWX 181854
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
254 PM EDT THU MAR 18 2010
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH FRIDAY AND WILL
PROMOTE CONTINUED WARMTH AND DRY WEATHER. A STRONG UPPER LEVEL
DISTURBANCE AND ITS ASSOCIATED COLD FRONT ARE EXPECTED TO IMPACT
THE REGION LATE SUNDAY THROUGH MONDAY.
&&
.NEAR TERM /THROUGH 6 AM FRIDAY/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL REMAIN OVER THE
REGION THROUGH FRIDAY. LIGHT WINDS AND MAINLY CLEAR SKIES WILL
ALLOW FOR RADIATIONAL COOLING TONIGHT...BRINGING SEASONABLY
CHILLY CONDITIONS WITH MIN TEMPS RANGING FROM NEAR FREEZING IN
SOME OF THE COLDER VALLEYS TO THE MID AND UPPER 40S IN DOWNTOWN
WASHINGTON/BALTIMORE.
&&
.SHORT TERM /FRIDAY/...
PLENTY OF SUNSHINE AND A DOWNSLOPING WESTERLY FLOW WILL BRING
EVEN MILDER CONDITIONS FRIDAY...WITH MAX TEMPS RANGING FROM NEAR
60 IN THE MOUNTAINS TO THE UPPER 60S AND 70S ACROSS MOST OTHER
LOCATIONS.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
A NUMBER OF WEEKEND IN RECENT MONTHS HAVE HAD ONE FORM OF INCLEMENT
WEATHER OR ANOTHER...SNOW/WIND/COLD. THIS COMING WEEKEND WILL BE
QUITE DIFFERENT. DAYTIME HIGHS ON SAT AFTN /FOR INSTANCE/ PEAKING
INTO THE L/M70S WILL BE SOME OF THE WARMEST SINCE LAST FALL - EARLY
NOV '09. CLEAR SKIES FOR MUCH OF THE DAY...LIGHT SLY WINDS -
PLEASANT ALL-AROUND FOR THE MID ATLC. THE NICE WX THOUGH IS JUST A
PRE-CURSOR TO THE NEXT LOW PRESSURE SYSTEM...THAT WILL BE DEVELOPING
ACROSS THE SRN PLAINS DURING OUR NICE WEEKEND.
THIS FEATURE IS A BIT MORE INTENSE THAN PREV RUNS HAVE INDICATED -
MAINLY BECAUSE THE SYSTEM WILL BE IN THE FORM OF A CUT-OFF UPPER LOW
THAT IS VERY DEEP FOR THIS TIME OF THE SEASON. MUCH OF THE ENERGY OF
THE SYSTEM WILL BE GIVEN-OFF AS THE LOW MAKES ITS FURTHEST SWD
EXTENT OVER THE OZARK MTNS/RED RIVER VLY. THE LOW WILL THEN BE
PICKED BY THE LONGWAVE OVER SRN CANADA AND DRIFT TOWARD THE SRN
APLCNS LATE SUN/EARLY MON. CLOUDS WILL BE ON THE INCREASE DURING THE
DAY SUNDAY...WHICH WON/T HAVE MUCH OF AN EFFECT ON TEMPS - MAYBE A
COUPLE OF DEGREES COOLER OVERALL. AS THE ATMOSPHERE BEGINS TO
MOISTEN...A FEW ISOLATED SHOWERS WILL MOVE THROUGH THE AREA TOWARD
EVENING - MORE SCATTERED ACTIVITY INTO THE OVERNIGHT HRS.
THE SFC LOW LOOKS TO MAKE A TREK ACROSS THE CNTRL APLCNS AND POTOMAC
HIGHLANDS DURING THE DAY ON MON - A BIT SLOWER THAN PREV RUNS
SHOWED. THE MINIMAL CONVECTIVE POTENTIAL WILL BE SOUTH AND EAST OF
THE LOW - BUT MAINLY E OF THE VA BLUE RIDGE AND ESPECIALLY CLOSER TO
THE COAST W/ THE MORE UNSTABLE ELEVATED LAYER AND A BIT BETTER WIND
SHEER VALUES. STILL...THESE ELEMENTS WILL BE MARGINAL ACROSS THE MID
ATLC - MUCH BETTER DOWN ACROSS THE SRN ATLC COAST. AS THE STILL COLD
UPPER CUT-OFF LOW MOVES ACROSS THE REGION OVERNIGHT MON INTO EARLY
TUE. SOME OF THIS COOLER AIR WILL BE MIXED DOWN TOWARD THE SFC WHICH
WILL TAKE TEMPS BACK DOWN INTO THE M/L30S. A MIX OF RAIN/SNOW WILL
BE POSSIBLE ACROSS THE WRN ZONES. ANOTHER WAVE OF LIGHT RAIN MAY
SLIDE THRU THE AREA ON TUE AFTN AS THE UPPER LOW FINALLY MAKES IT/S
EXIT OFF THE ATLC.
ANOTHER COUPLE OF HIGH PRESSURE DAYS BEFORE THE NEXT LOW PRESSURE
SYSTEM GEARS UP OVER ROUGHLY THE SAME AREA. TOO EARLY TO TELL HOW
FAR SOUTH THIS SYSTEM WILL DEVELOP AND THEN MOVE.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS THROUGH FRIDAY. LIGHT WINDS THROUGH TONIGHT WILL
BECOME WEST-NORTHWEST FRIDAY WITH OCCASIONAL GUSTS AROUND 10 TO 15
KNOTS. THERE WILL BE OCCASIONAL HIGH CLOUDS THROUGH FRIDAY.
VFR CONDITIONS /SKC-LIGHT WINDS/ ALL-DAY SAT AND MUCH OF SUNDAY.
MID-UPPER CLOUD DECKS WILL MOVE IN LATE SUN...W/ ANOTHER LOW
PRESSURE SYSTEM MOVING THRU ON MON - EXITING ON TUE. BREEZY SFC
WINDS...SUB-VFR CLOUDS AND OCCASIONAL SHOWERS W/ THIS SYSTEM ON
MONDAY. HIGH PRESSURE FOR THE MIDDLE PART OF NEXT WEEK.
&&
.MARINE...
ONSHORE WINDS THIS AFTERNOON WILL BECOME NORTHWEST TONIGHT INTO
FRIDAY MORNING. WINDS WILL TURN ONSHORE DURING THE AFTERNOON HOURS
FRIDAY. NO FLAGS ARE ANTICIPATED THROUGH FRIDAY.
MAINLY LIGHT WINDS THIS WEEKEND OVER THE WATERS. A LOW PRESSURE
SYSTEM WILL APPROACH LATE SUN INTO EARLY MON. SLY WINDS WILL
INCREASE...WHICH MAY CREATE INTERMITTENT SCA CONDITIONS - LASTING
THRU THE EXIT OF THE LOW ON TUE. THEN...HIGH PRESSURE WILL BUILD
INTO THE REGION.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...BJL
LONG TERM...GMS
AVIATION...BJL/GMS
MARINE...BJL/GMS
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