Flash Flood Warning 70, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
122 PM EDT TUE SEP 27 2011

.SYNOPSIS...
THE MIDWEST CLOSED UPPER LOW WILL CONTINUE TO SPIN NEAR THE
SOUTHERN END OF LAKE MICHIGAN OVER THE NEXT FEW DAYS. A SECOND
AREA OF UPPER LEVEL ENERGY WILL DIG SOUTHEASTWARD FROM THE UPPER
GREAT LAKES AND HELP TO CARVE OUT A DEEP LONG WAVE TROUGH OVER THE
EASTERN U.S. BY THE WEEKEND. THIS TROUGH WILL CREATE NORTHWESTERLY
FLOW WHICH WILL LEAD TO A COOLING TREND WITH TEMPERATURES BELOW
NORMAL FROM FRIDAY THROUGH THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
CURRENT RADAR TRENDS DO INDICATE THAT THE FIRST LINE OF STORMS
THAT PRODUCED 1-2 INCHES OF RAIN AS IT MOVED THROUGH THE CENTRAL
MTS IS WEAKENING BUT SLOWING DOWN AS EXPECTED. THE TROUBLE LIES IN
THE UPSTREAM AREAS OF NRN VA/ERN WV/WRN MD. HRRR WHICH HAS HANDLED
THE PLACEMENT AND TIMING OF RAIN WELL SO FAR CONTINUES TO
REDEVELOP STORMS OVER THAT AREA AS SUN BREAKS OUT AND LOWERS
STABILITY. IT IS ALREADY STARTING TO VERIFY. RUC SHOWS SIMILAR
SCENARIO WITH AXIS OF RAINFALL STILL EXPECTED TO BE TO THE EAST OF
THE OCCLUSION. WONDERING IF I SHOULD HAVE CHOPPED THE NWRN PARTS
OF THE CWA OFF THE FFA SO QUICKLY. FIRST INSTINCTS ARE USUALLY
PRETTY GOOD...WHILE HINDSIGHT IS ALWAYS THE BEST. PWATS REMAIN
HIGHER THAN NORMALS TO THE EAST OF STATE COLLEGE TONIGHT...BUT
PLACEMENT OF THE OCCLUSION OVER WRN PA MEANS THAT HEAVY RAIN CAN
STILL OCCUR BACK THROUGH MOST/ALL OF THE CWA. WHILE FIRST THOUGHT
IS THAT THE HEAVIEST OF THE RAIN WOULD BE MAINLY ALONG AND EAST OF
THE ALLEGHENY FRONT. HOWEVER...THE AXIS OF THE MAIN BAND OF
CONVERGENCE SEEMS LIKE IT WOULD TILT A LITTLE NEGATIVE THIS
EVENING AND TONIGHT/S RAIN COULD BE HEAVIEST ALONG/WEST OF THE
RIDGES. THUS...WILL KEEP POPS HIGH FOR MUCH OF THE AREA.
CLOUDS/RAIN AND LINGERING MOISTURE WILL KEEP THE TEMPS WARM/MILD
TONIGHT.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
THE CLOSED H5 MIDWEST VORTEX INVOF SRN LAKE MI AT THE START OF
THE PD WILL BEGIN TO SHIFT EWD INTO NRN INDIANA DURING THE DAY
WED. THE LEAD S/WV TROUGH IS THEN FCST TO TAKE ON A SLIGHT NEG
TILT AS IT OPENS AND ACCELERATES NEWD THROUGH THE UPPER OH VLY
AND ERN GRT LKS WED NGT-THUR...AS A SECONDARY UPPER DISTURBANCE
AND ATTENDANT SPEED MAX QUICKLY DROPS SEWD ON ITS HEELS THROUGH
THE UPPER MIDWEST/GLKS. THE ARRIVAL OF CANADIAN S/WV ENERGY WILL
HELP TO CARVE OUT A UNSEASONABLY STRONG EARLY FALL SEASON LONGWAVE
TROUGH IN THE EAST BY THE END OF THE PD. MDLS ARE IN FAIRLY GOOD
AGREEMENT CONCERNING THE LG SCALE PATTERN EVOLUTION...BUT THE GFS
REMAINS SLIGHTLY FASTER THAN CONSENSUS WITH THE EJECTION OF THE
LEAD S/WV ENERGY.

IN GENERAL MDLS SHOW A REGION OF ENHANCED LIFT ON ERN PERIPHERY OF
CLOSED UPPER LOW OVERSPREADING LOW-LEVEL CONVERGENCE AXIS
OVR CNTRL PA ON WED. ALTHOUGH DESTABILIZATION IS EXPECTED TO BE
LIMITED IN ENVIRONMENT CHARACTERIZED BY MOIST SELY FLOW IN THE LOW
LEVELS....IT DOES APPEAR THAT A NARROW AXIS OF DEEPER PWS/MOISTURE
AND INSTABILITY MAY PROVE FAVORABLE FOR ISOLD CONVECTIVE
DEVELOPMENT AND MOD-LCL HVY RNFL AMTS. SPC HAS PLACED SEE TEXT
OVER SERN PA FOR DAY 2. STRONG HEIGHT FALLS AND ENHANCED UPPER
LEVEL DYNAMICS IN ASSOC WITH H5 ENERGY UNRAVELING TO NEG TILT AND
LIFTING NEWD ACRS PA SHOULD PROVIDE ANOTHER OPPORTUNITY FOR MOD
RAINS ON THURS. WHILE TIMING OF PCPN MAY SHIFT BY 6 HOURS OR SO
CONFIDENCE IS HIGH AND THEREFORE HAVE ADJUSTED POPS UPWARD BY
10-15 PCT INTO LKLY CATG FOR DAYS 2 AND 3 WITH QPF COMPRISED
MAINLY OF HPC.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE LG SCALE PATTERN IN THE EAST LOOKS MORE LIKE WINTER THAN
EARLY FALL. CONFIDENCE IS ABOVE NORMAL THROUGH MUCH OF THE PERIOD
AS ALL MDL AND ENSEMBLE GUID CARVES OUT AN ANOMALOUS TROF OVR THE
ERN U.S. LATE THIS WEEK INTO THE WEEKEND. BY MONDAY THE GFS IS
PROBABLY TOO OPTIMISTIC/PROGRESSIVE IN BUILDING HEIGHTS IN THE
EAST AND GOES AGAINST THE 00Z ECMWF/ECENS/GEFS CONSENSUS.

A SIGNIFICANT COOLING TREND IS EXPECTED WITH DAYTIME TEMPERATURE
DEPARTURES OF 10-15F BELOW NORMAL. WEATHER CONDS SHOULD TURN MUCH
COLDER ON FRIDAY WITH GUSTY WINDS USHERING IN THE COLD AIR BEHIND
THE MAIN SYNOPTIC FROPA. SATURDAY LOOKS LIKE THE COLDEST DAY
RIGHT NOW WITH HIGHS MID 40S MTNS TO UPPER 50S IN THE SE. THE
BROAD CYC FLOW ALOFT FAVORS THE WESTERN HIGH TERRAIN IN TERMS OF
PCPN CVRG AS NWLY FLOW ALOFT SHOULD LEAD TO LAKE EFFECT/UPSLOPE
SHOWERS.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
LINE OF SHOWERS/TSTMS MOVING PAST IPT IS STALLING BEFORE REACHING
MDT/LNS. IT WILL MOST LIKELY STALL RIGHT THERE AND MAY EVEN PIVOT
BACK TO THE WEST A BIT OVER UNV/AOO/BFD FOR THIS EVENING. LOW
CIGS AND SHRA/TSRA CAN CREATE MVFR AND LOCAL IFR CONDS FOR MANY
LOCATIONS THIS AFTN/TONIGHT. WET AND CLOUDY WITH NUMEROUS SHRA
/AND POSS TSRA/ IS THE BEST SUMMATION. LGT WINDS AND WET GROUND
WILL LIKELY RESULT IN WIDESPREAD FOG/LOW VSBYS REDEVELOPING
TONIGHT...UNLESS THE RAIN CAN ACTUALLY KEEP THE VSBYS UP BY
COALESCING THE LLVL DROPS.

OUTLOOK...
WED...LOW CIGS/RAIN POSSIBLE...ESP EAST.
THU...AM FOG POSSIBLE.
FRI-SAT...LOW CIGS/SHRA POSS W MTNS...MAINLY AT NIGHT.

&&

.HYDROLOGY...
FLASH FLOODING HAS ALREADY BEEN REPORTED IN A FEW LOCATIONS THIS
MORNING. FLASH FLOOD WATCH WAS TRIMMED OF THE NW PORTION...BUT
PERHAPS PREMATURELY. THAT AREA HAS BEEN DRIER THAN THE REST OF THE
AREA DURING THE PAST 24 HRS THOUGH.

PWATS NEARING 1.75 INCHES IN THE SRN PART OF THE AREA...BUT
ONLY AROUND AN INCH IN THE EXTREME WEST. MDLS HAVE COME TO FAIR
AGREEMENT ON THE PLACEMENT OF THE SFC FEATURES AND MOISTURE
CONVERGENCE FOR TONIGHT. THE AXIS OF THE HEAVIEST/REPEATING
SHOWERS AND EMBEDDED THUNDER WILL MOST LIKELY PIVOT FROM CURRENT
SSW-NNE TO MOR NNW-SSE THIS EVENING AS THE UPPER FLOW BACKS A
LITTLE.

CERTAINTY LIES IN THE CALL FOR MOISTURE TO REMAIN HIGH THROUGH
THE NEXT THREE DAYS DUE TO THE SRLY FLOW TO THE EAST OF THE BIG
UPPER LOW. SAT PRECIP ESTIMATES AND WV LOOP INDICATE THAT WE COULD
ACTUALLY BE TAPPING MOISTURE FROM DEEP IN THE CARRIBBEAN. ANOTHER
SHORTWAVE THAT KICKED OFF STORMS ACROSS THE LWR MS VALLEY LAST
NIGHT WILL MOVE NORTHWARD INTO THE MID ATLANTIC TONIGHT. NO
SHORTAGE OF FORCING THERE...AND MOISTURE AND LLJET TRANSPORTING
MOISTURE FROM THE SE WILL KEEP THE FCST WET...PERHAPS TOO WET.
RADAR DOING WELL WITH ESTIMATES AT THIS TIME. EXPECT MOST PROBLEMS
TO BE ISOLATED...BUT FFG IS LOW ATTM...AND NEW GUID WHICH WILL
TAKE INTO ACCT OVERNIGHT RAINFALL IS ON THE WAY AND WILL CERTAINLY
BE LOWER.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR PAZ006-012-018-
019-024>028-033>037-041-042-045-046-049>053-056>059-063>066.

&&

SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...DANGELO
HYDROLOGY...DANGELO

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1207 PM EDT TUE SEP 27 2011

PAZ006-012-018-019-024>028-033>037-041-042-045-046-049>053-056>059-
063>066-281615-
POTTER-NORTHERN CLINTON-NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-
BLAIR-HUNTINGDON-MIFFLIN-JUNIATA-SOMERSET-BEDFORD-FULTON-FRANKLIN-
TIOGA-NORTHERN LYCOMING-SULLIVAN-SOUTHERN CLINTON-SOUTHERN LYCOMING-
UNION-SNYDER-MONTOUR-NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-
SCHUYLKILL-LEBANON-CUMBERLAND-ADAMS-YORK-LANCASTER-
1207 PM EDT TUE SEP 27 2011

...FLASH FLOOD WATCH IN EFFECT THROUGH WEDNESDAY MORNING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO
WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE
INFORMATION ABOUT THE FOLLOWING HAZARDS.

   FLASH FLOOD WATCH.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO
WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE
INFORMATION ABOUT THE FOLLOWING HAZARDS.

   FLASH FLOOD WATCH.

HEAVY RAIN WILL CONTINUE TO POSSIBLE THROUGH THURSDAY AS THE LARGE
UPPER LOW SPINS NEARLY STATIONARY OFF TO THE WEST OF THE STATE.
RIVER FLOODING MAY BECOME POSSIBLE THIS WEEK AS THE RAIN
CONTINUES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

PAZ004-005-010-011-017-281615-
WARREN-MCKEAN-ELK-CAMERON-CLEARFIELD-
1207 PM EDT TUE SEP 27 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

HEAVY RAIN WILL CONTINUE TO POSSIBLE THROUGH THURSDAY AS THE LARGE
UPPER LOW SPINS NEARLY STATIONARY OFF TO THE WEST OF THE STATE.
RIVER FLOODING MAY BECOME POSSIBLE THIS WEEK AS THE RAIN
CONTINUES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1138 AM EDT TUE SEP 27 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1055 AM     FLASH FLOOD      STATE COLLEGE           40.79N  77.86W
09/27/2011                   CENTRE             PA   PUBLIC

            1 FOOT OF WATER ON ATHERTON ST.

&&

EVENT NUMBER CTP1100462

KREKELER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1156 AM EDT TUE SEP 27 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1150 AM     FLASH FLOOD      CASSVILLE               40.29N  78.03W
09/27/2011                   HUNTINGDON         PA   EMERGENCY MNGR

            STRUCTURAL FLOODING REPORTED IN CASS TOWNSHIP

&&

EVENT NUMBER CTP1100463

KREKELER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1200 PM EDT TUE SEP 27 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1047 AM     FLASH FLOOD      3 S SAXTON              40.17N  78.25W
09/27/2011                   BEDFORD            PA   911 CALL CENTER

            WATER AND DEBRIS OVER ROAD IN COALDALE

&&

EVENT NUMBER CTP1100464

KREKELER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
201 PM EDT TUE SEP 27 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0200 PM     FLASH FLOOD      CHAMBERSBURG            39.93N  77.66W
09/27/2011                   FRANKLIN           PA   EMERGENCY MNGR

            FLOODING ON MAIN ST. IN CHAMBERSBURG

&&

EVENT NUMBER CTP1100465

KREKELER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
214 PM EDT TUE SEP 27 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0212 PM     FLASH FLOOD      PORT ROYAL              40.53N  77.39W
09/27/2011                   JUNIATA            PA   EMERGENCY MNGR

            FLOODED BASEMENTS AND ROAD CLOSURES IN AND AROUND PORT
            ROYAL

&&

EVENT NUMBER CTP1100466

KREKELER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
236 PM EDT TUE SEP 27 2011

PAZ026-036-063-271930-
CUMBERLAND PA-FRANKLIN PA-HUNTINGDON PA-
236 PM EDT TUE SEP 27 2011

...A STRONG THUNDERSTORM WILL AFFECT FRANKLIN...SOUTHEASTERN
HUNTINGDON AND SOUTHWESTERN CUMBERLAND COUNTIES...

AT 233 PM EDT...A STRONG THUNDERSTORM WAS NEAR CLAYLICK...MOVING
NORTHEAST AT 25 MPH.

WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM.
THIS STORM WILL AFFECT FORT LOUDON...ST. THOMAS...UPPER STRASBURG AND
ROXBURY.

THIS WILL IMPACT THE FOLLOWING CENTRAL PENNSYLVANIA INTERSTATES...THE
PENNSYLVANIA TURNPIKE BETWEEN MILE MARKERS 185 AND 204...I-81 BETWEEN
MILE MARKERS 4 AND 34.

THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 11...ROUTE
30.

LAT...LON 3980 7803 3987 7797 4001 7792 4006 7786
      4008 7789 4027 7780 4009 7734 3971 7779
      3972 7807

FORECASTER: MARTIN

!--CTA_MARKER_NO