489
FXUS61 KLWX 240758
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
358 AM EDT THU JUL 24 2008
SYNOPSIS
A COLD FRONT WILL MOVE EAST OF THE CHESAPEAKE BAY THIS MORNING.
HIGH PRESSURE WILL MOVE INTO THE REGION TODAY AND TONIGHT. ANOTHER
COLD FRONT WILL CROSS THE AREA ON SUNDAY. HIGH PRES WILL BUILD
OVER THE REGION NEXT WEEK.
NEAR TERM /TODAY/
AFTER A FAIRLY ACTIVE PD OF WX IT'S NICE TO SEE THE CD FNT MOVG
OUT OF THE CWA. PROBLEM OVR THE NEXT FEW HRS IS GOING TO BE FOG
FORMATION. CHO/MRB HV GONE "POOF" IN DCRSD VSBYS IN PAST HR AS
SKIES HV CLRD...AND IN FRONT OF THE OFFICE IT LOOKS LK IT MAY AS
WELL ON THE IAD RUNWAY. WE'LL KEEP AN EYE ON THIS...WL PUT PTCHY FOG W
OF THE CITIES IN THE ZNS FOR THE ERLY MRNG HRS. AS DAWN APPROACHES
WE'LL SEE IF FOG IS DENSE/WIDESPREAD ENUF TO WARRANT AN ADVSRY.
ETA BUFKIT SEEMS TO HV A GOOD HANDLE ON THIS...AND PREDICTS IT WL
BURN OFF B4 9 AM.
AFTR THAT A RATHER COMFORTABLE DAY LOOKS TO BE ON TAP FOR THE RGN.
M SUN SKIES..TEMPS REACHING THE M80S E OF THE MTNS...U70S AT THE
HIER ELEVS.
SHORT TERM /TONIGHT/
HIGH PRES OVR RGN TNGT. "LATE JUL" AND "GOOD SLEEPING WX" ARE
GNRLY MUTUALLY EXCLUSIVE TERMS...BUT W/ OVRNGT LOWS XPCTD TO BE
5-10 DEGS BLO NRML THE UPCOMING NGT LOKS TO BE A PLSNT ONE.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
A MORE DIFFICULT LONG TERM W/ THE IMMENSE UNCERTAINTY W/ THE UPPER
LOW THRU THE END OF THE WEEK...INTO EARLY NEXT WEEK. THEN...FOLLOWED
CLOSELY BY ANOTHER ACTIVE UPPER LEVEL SYSTEM WHICH MAY OR MAY NOT
DIP FURTHER SOUTH /INTO THE MID ATLNC REGION/ BY THIS TIME NEXT
WEEK.
TACKLING THE MORE IMMEDIATE FEATURE...00Z GFS HAS BACKED OFF
FROM THE INTENSE UPPER TROF AXIS FOR SATURDAY. THE FOCUS NOW ON A
SLOWLY DEVELOPING LONG WAVE TROF THE DIGS S/WRD ACROSS THE GREAT
LAKES REGION AND INTO THE CNTL APLCHNS INTO EARLY NEXT WEEK.
EMBEDDED IN THE FLOW ARE SEVERAL WEAK AXIS REGIONS THAT PUSH
ACROSS THE REGION ABOUT EVERY OTHER DAY. THERE/S LITTLE POINT IN
TRYING TO PIN DOWN EXACT TIMING/STRENGTH OF ANY INDIVIDUAL UPPER
LIFTING MECHANISM. FUTURE RUNS MAY DEVELOP AN EVEN FURTHER DEEPENING
TROF /LIKE THE ONE THAT IS CURRENTLY EXITING OFF THE ATLNC COAST/.
ONE CERTAINTY IS THAT EVEN W/ THE TIMING AND PROGRESSION DIFFERENCES
IN THE LONG RANGE MODELS...THE ERN HALF OF THE COUNTRY /AND ESPC THE
NE QUADRANT/ IS STILL IN A FAIRLY ACTIVE PATTERN FOR LATE JULY. THIS
IS EVIDENCED BY THE MID-LATE WEEK /NEXT WEEK/ SYSTEM THAT MODELS ARE
FAIRLY PROGRESSIVE IN PAINTING ACROSS THE REGION.
LONG RANGE HIGH TEMPS WILL BE NEAR PERSISTENCE /AND NEAR NORMAL/ W/
ONLY A DEGREE OR TWO DIFFERENCE THRU THE WEEKEND INTO EARLY NEXT
WEEK. KEPT CHANCE POPS IN FOR SAT AS DECENT WAA AND MOIST S/RLY FLOW
WILL ENTER THE REGION. A WEAK IN-SITU CAP MAY LIMIT WIDESPREAD CONVN
THO AT LEAST ISLTD TO PSBLY SCT/D STORMS MAY DEVELOP ALONG SFC
BOUNDARIES FROM THE STRONGER THAN NORMAL SFC S/RLY FLOW...ALONG W/
THE APRCH OF A SLIGHTLY DEEPENING UPPER SHRTWV TROF FROM THE WEST.
BY SUN AFTN...THE WEAKLY NEGATIVELY TILTED TROF AXIS EXPTD TO BE
OVERHEAD. IN SUBSEQUENT UPDATES...SUN MAY HAVE THE BETTER CHANCE
FOR WIDESPREAD ACTIVITY ACROSS THE MID ATLNC REGION...THO THE NAM
HAS NEARLY ZONAL FLOW SETTLED OVER THE NE QUAD. PSBLE SFC COLD FRONT
MAY DRIFT SLOWLY ACROSS THE AREA LATE SUN AND OFF THE ATLNC COAST BY
EARLY MON. SUMMERTIME DIURNAL INSTABILITY MAY IN FACT END UP BEING
THE MAIN MODE FOR DEVELOPMENT DRNG THIS PERIOD...AND INTO THE MIDDLE
PART OF NEXT WEEK.
AVIATION /TODAY THROUGH MONDAY/
POOR VSBYS AT IAD/MRB/CHO THRU 13Z IN FOG. AFTERWARDS VFR CONDS AT
ALL TAF SITES FOR RMDR OF TDA. HIGH PRES BUILDS IN TNGT. QUSTN
EXISTS OF WHETHER AIR WL BE DRY ENUF TO SUPPRESS FOG FORMATION
OVRNGT. LATER SHIFTS CAN EVALUATE.
LITTLE CONCERN GOING INTO THE WEEKEND...THO SAT AFTN MAY SEE SOME
SCT/D STORMS AND A REPEAT FOR SUN. A COLD FRONT EXPTD TO MOVE THRU
THE REGION ON SUN W/ BRIEF INFLUENCE OF HIGH PRES FOR EARLY NEXT
WEEK.
MARINE
RW EXITING THE BAY W/ THE DEPARTING CD FNT. HIGH PRES TO BUILD
INTO THE WATERS THIS AFTN. FOR NOW WL CAP THE WINDS AT 15 KT. LGT
WINDS TNGT.
HIGH PRES FOR THE REST OF THE WEEK...W/ S/RLY WIND INCR ON SAT AFTN
W/ PSBLE SCA COND/S AND SCT/D STORMS ALSO PSBLE FOR THE AFTN/EVNG
HRS. A FAIRLY SIMILAR SCENARIO FOR SUNDAY AS A COLD FRONT THEN
SLIDES ACROSS THE AREA BY LATE SUN. HIGH PRES INTO THE MIDDLE OF
NEXT WEEK.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
PRODUCTS...WOODY!/GMS
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