000
FXUS61 KPBZ 052358
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
758 PM EDT SUN JUL 5 2009

.SYNOPSIS...
HIGH PRESSURE COMING SLOWLY FROM NEBRASKA WILL PROVIDE THE UPPER
OHIO VALLEY WITH GENERALLY DRY CONDITIONS THIS WORK WEEK ALONG
WITH NEAR SEASONABLE TEMPERATURES.

&&

.NEAR TERM /THROUGH MONDAY/...
JUDGING FROM RECENT SURFACE AND SATELLITE DATA EXPECT MAINLY
PATCHES OF HIGH CIRRUS TYPE CLOUDS ACROSS THE UPPER OHIO VALLEY
TONIGHT. RECENT SURFACE DEW POINTS COUPLED WITH NAM MODEL
SOUNDINGS SHOW LITTLE FOG FORMATION EXPECTED MONDAY MORNING
FOLLOWED BY SCATTERED DAYTIME CUMULUS CLOUDS MONDAY.

FORECASTED TEMPERATURES USING A BLEND OF NAM AND GFS MOS VALUES.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
STILL MUCH UNCERTAINTY AS TO WHETHER THERE WILL BE AN OUTBREAK OF
SHOWERS AND THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY TUESDAY
INTO WEDNESDAY. A COUPLE SREF AND GEFS MODEL RUN MEMBERS SHOW AN
UPPER LOW PRESSURE SYSTEM MOVING SOUTHEASTWARD THROUGH THE GREAT
LAKES DURING THAT TIME PERIOD. HOWEVER ONLY THE NAM OPERATIONAL
MODEL RUNS SHOW SUFFICIENT BOUNDARY LAYER MOISTURE /EVIDENCED BY
SURFACE DEW POINTS IN THE LOWER 6OS/ AND HENCE SUFFICIENT
INSTABILITY AND TRIGGERING BOUNDARY LAYER LIFT TO EXTEND INTO
OHIO AND NORTHERN WEST VIRGINIA COUNTIES. FOR NOW OPTED NOT TO
MENTION ALTHOUGH NAM AND GFS MOS PROBABILITY OF PRECIPITATION /POP/
VALUES AT TIMES PEAKED INTO CHANCE RANGE.

FORECASTED TEMPERATURES TO BE EITHER NEAR OR SLIGHTLY COOLER THAN
NORMAL BASED ON BLEND OF NAM AND GFS MOS VALUES.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER THE NORTHEAST WILL PERSIST SLIGHTLY LONGER THAN 
PREVIOUSLY EXPECTED. THIS SHOULD ALLOW THE WEATHER TO REMAIN DRY FOR 
BOTH THURSDAY AND FRIDAY. BY SATURDAY LOW PRESSURE OVER HUDSON BAY 
WILL BRING A COLD FRONT INTO THE UPPER OHIO VALLEY...BRINGING A 
CHANCE OF SHOWERS AND THUNDERSTORMS. THE GFS IMMEDIATELY CLEARS THIS 
FRONT...WHILE THE ECMWF AND CANADIAN MODELS HANG THE FRONT UP OVER 
THE AREA INTO SUNDAY. WILL KEEP THE CHANCE OF RAIN THROUGH THE 
ENTIRE WEEKEND.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
EXPECT PREVALENT VFR THIS PERIOD. 

VFR CONDITIONS CAN BE EXPECTED OVERNIGHT IN THE WEAK RIDGING
BETWEEN THE CLOSED LOW NORTH OF THE LAKES AND THE COLD FRONT
ACROSS THE SOUTHEAST STATES. MAY SEE SLIGHT REDUCTIONS IN
VISIBILITY OVERNIGHT WITH PATCHY MORNING FOG MAINLY IN THE
RIVER VALLEYS. SOME GENERAL VFR CEILINGS MAY AFFECT SITES WITH SYSTEM
CLIPPING THE NORTHEASTERN PORTIONS OF THE REGION MONDAY NIGHT INTO
WEDNESDAY. GENERAL VFR CONDITIONS CAN BE EXPECTED THROUGH THE
FORECAST PERIOD.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$