Short Term Forecast - Lancaster (Pennsylvania) Issued ... [Click here for more]
Weather data updated: 4:50:28 AM 
AREA FORECAST DISCUSSION 
000
FXUS61 KCTP 280836
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
415 AM EDT THU AUG 28 2008

.SYNOPSIS...
MOISTURE FROM THE REMNANTS OF OLD TROPICAL STORM FAY WILL BE
FOCUSED ACROSS CENTRAL PENNSYLVANIA TODAY AND TONIGHT...BRINGING
SOME NEEDED RAINFALL. A COLD FRONT OVER THE UPPER MISSISSIPPI
VALLEY THIS MORNING WILL MOVE EAST AND CROSS THE COMMONWEALTH
FRIDAY NIGHT AND SATURDAY. THIS FRONT WILL BE PRECEDED AND
ACCOMPANIED BY A FEW MORE SHOWERS AND SCATTERED AFTERNOON
THUNDERSTORMS FRIDAY. MODERATING TEMPERATURES WILL FOLLOW
FOR THE WEEKEND AS A LARGE AREA OF HIGH PRESSURE BUILD EAST
ACROSS THE REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
A RATHER NARROW CHANNEL OF HIGH THETA-E AIR/PWAT OF 38-40MM
(+1-2 STANDARD DEVIATIONS) WILL DRIFT SLOWLY NE ACROSS CENTRAL
PENN TODAY INTO TONIGHT. 850 HPA THETA-E CONVERGENCE WILL PEAK
LATE THIS MORNING AND THIS AFTERNOON ACROSS THE ALLEGHENY FRONT
AND ADJACENT SCENT MTNS...ROUGHLY 50 NM EITHER SIDE OF A LINE
FROM KBFD TO KFIG...KAOO AND KMRB. THIS LLVL FOCUS WILL FIZZLE
SLOWLY TONIGHT JUST 30-50 NM FURTHER EAST ACROSS CENTRAL PENN
TONIGHT...CAUSING THE RAIN OF VARYING INTENSITY TO TAPER TO MORE
OF A SHOWERY PATTERN.

NAM PRECIP AMT AND ORIENTATION OF ITS AXIS (SSE TO NNW) LOOKS TO
BE BETTER REPRESENTATIVE OF THE CURRENT LOCATION AND CONFIGURATION
OF THE STRATIFORM RAIN.

MARFC SENIOR HAS QPF IS WELL COLLABORATED WITH OUR CURRENT SET OF
QPF GRIDS WITH THE MAIN AXIS OF HEAVIER STORM TOTAL QPF OF NEARLY
1.5 INCHES JUST TO THE SW OF A KBFD TO KUNV AND KHGR LINE.
RAINFALL EAST OF THE SUSQ MAINSTEM...NOT EXPECTED TO START UNTIL
THIS AFTERNOON IN MOST SPOTS...WILL BE AOB 0.25" THROUGH LATE
TONIGHT.

THE BEST CHANCE OF RAIN ACROSS THE EXTREME WRN ZONES THROUGH THIS
MORNING WILL BE TAPERING TO SCATTERED SHOWERS LATE TODAY. THE
SCATTERED SHOWERS WILL LINGER ACROSS THE FAR EAST...AND FAR WEST
ZONES...WITH THE MAIN (NARROW) AXIS OF SHOWERS SITUATED JUST WEST
OF THE SUSQ MAIN STEM...TO THE NCENT PENN MTNS. ADDITIONAL QPF
TONIGHT WILL BE BETWEEN 0.25 AND 0.40" WITHIN THIS AXIS...WHILE
AREAS EITHER SIDE WILL SEE RAINFALL NEAR OR BELOW 0.10".

INITIALLY DRY LLVL AIR WILL LEAD TO 5-8F OF COOLING TWD THE WET BULB
DURING THE FIRST FEW HRS OF RAIN THIS MORNING ACROSS CENTRAL PENN.
EXPECT AFTERNOON MAXS TO BE RATHER FLAT FROM MID TO LATE MORNING
TEMPS. HIGHS WILL RANGE FROM THE MID TO UPPER  60S ACROSS THE CENTRAL
AND WEST...TO 69-73 ACROSS THE MID/LWR SUSQ VALLEY AND POINTS TO THE
EAST.


&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
PRECIP BECOMES MORE SHOWERY AND SCATTERED AHEAD OF AN APPROACHING
CFRONT. SFC-850 BASED LIFTED INDICES STAY POSITIVE ACROSS
PRACTICALLY THE ENTIRE REGION EAST OF THE ALLEGHENY PLATEAU THANKS
TO THE PERSISTENT ALBEIT RATHER LIGHT SE SFC-925 HPA FLOW AND
WIDESPREAD STRATUS/STRATO CU CLOUDS BASED ANYWHERE FROM 2-5KFT AGL" onClick="return popup(this, 'notes')">AGL.

MAX TEMPS IN THE LOWER TO MID 70S MAY BE ON THE OPTIMISTIC
SIDE...ESPECIALLY IF SHOWERS ARE MORE NUMEROUS THAN CURRENTLY
EXPECTED.

KEPT THE CHC OF TSRA IN THE GRIDS/ZONE TEXT FRO NOW FRIDAY
AFTERNOON/NIGHT SINCE WE`LL SEE A 10-20KT SW-W FLOW SEVERAL KFT
AGL - ADVECTING SLIGHTLY NEG LIFTED INDICES ABOVE THE COOL STABLE
NEAR SFC LAYER. TEMPS SHOULD REBOUND TO NEAR NORMAL HIGHS FOR
SATURDAY IN THE WAKE OF THE FRONT WITH CLEARING SKIES.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ENSEMBLES ADVERTISE BROAD RIDGE SETTING UP SHOP THIS WEEKEND AND
DOES NOT SHOW SIGNS OF DEPARTING UNTIL AFTER MID-WEEK. SUN
MORNING WILL PROBABLY FEATURE SOME MORNING FOG AND POSSIBLY AGAIN
EARLY MON AS WELL.

DESPITE PRECIP FROM A FEW DAYS PRIOR...BNDRY LYR WILL QUICKLY DRY
OUT FROM SFC RIDGE. EXPECT SFC HEAT CAPACITY TO REMAIN LOW
ALLOWING AFTN TEMPS TO WARM TO NEAR GUIDANCE POSSIBLY A DEGREE OR
TWO ABOVE GUIDANCE...BUT REMAIN SEASONAL. DRY WX HOLDS IN PLACE
THROUGH WED ATTM.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
TROPICAL REMNANTS STRUGGLE TO SATURATE BNDRY LYR THIS
MORNING...DESPITE RADAR RETURNS INDICATING NUMEROUS RAIN SHOWERS
ACROSS THE ALLEGHENIES. MOST AIRFIELDS REMAIN AT VFR
CONDS...HOWEVER EXPECT THAT BTWN 06-10Z MANY SITES WILL FINALLY
SATURATE THE LLVLS AND LOWER CIGS TO ARND BKN/OVC AOA 1-3KFT
AGL...WITH GUIDANCE HINTING AT THIS CRITERIA PERSISTING THRU 00Z
FRI. VCSH WILL GIVE WAY TO STEADIER SHRA...WITH PERIODS OF VSBYS
BE REDUCED TO ARND MVFR TEMPO IFR MAINLY DURING NOCTURNAL HOURS.

AIRFIELDS WILL CONTINUE TO SEE REDUCED CIGS/VSBYS THRU FRI EARLY
SAT AS AN AREA OF HIGH PRESSURE ALLOWS COOLER MOIST BNDRY LYR
AIRMASS TO FILTER IN FROM THE EAST...BEFORE BROAD AREA OF HIGH
PRESSURE ACROSS THE OHIO RVR VALLEY MOVES IN FOR THE MID WEEKEND
PERIOD BRINING VFR BACK FOR THE REMAINDER OF THE WEEKEND. SAT NGT
EARLY SUN WILL FEATURE BEST CHC FOR FOG TO DEV...POSSIBLY BRINGING
IFR/LIFR TO NUMEROUS AIRFIELDS BEFORE MIXING OUT AFTER SUNRISE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&