Alert archive / Pennsylvania / Flood Watches in 2015

Flood Watch 1, NWS State College, PA

March 4, 20155 counties in Pennsylvania

NWS State College, PA issued this flood watch at Mar 4, 2015, 3:02 AM EST for 5 counties in Pennsylvania. It was in force for 16 hr.

The area

The counties it named.

The facts

Issued
Mar 4, 2015, 3:02 AM EST (08:02 UTC)
Expired
Mar 4, 2015, 7:00 PM EST
In force
16 hr
Issued by
NWS State College, PA
Flood severity
None

Counties Bedford County, PA, Blair County, PA, Cambria County, PA, Clearfield County, PA, Somerset County, PA

The radar

The State College radar (KCCX), 78 km from the middle of the area, began a volume at 08:02 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 8.0 hours before the alert went out and 191 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 00:00Z on 2015-03-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2015-03-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 904 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
909 m above ground
0-6 km bulk shear
89 kt
0-1 km storm-relative helicity
904 m²/s²
0-3 km storm-relative helicity
1059 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS State College, PA wrote its last area forecast discussion before this flood watch went out at Mar 4, 2:12 AM EST, 50 minutes earlier.

Area forecast discussion, Mar 4, 2:12 AM EST, 50 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
212 AM EST WED MAR 4 2015

.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTH OF PENNSYLVANIA THIS MORNING...AS
ITS TRAILING COLD FRONT SAGS SOUTH THROUGH THE REGION. A WAVE OF
LOW PRESSURE WILL TRACK SOUTH OF PENNSYLVANIA LATE TODAY INTO
THURSDAY. HIGH PRESSURE WILL BUILD SOUTHEAST INTO THE STATE
FRIDAY AND SATURDAY.

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
DID ADJUST THE ADVISORY SOME...CLEARFIELD STILL NEAR 32...WHILE
OTHER SITES ABOVE 32.

OVERALL THE LL JET AND ASSOC PUSH OF WARM AIR ALOFT HAS CHANGED
PRECIP TO PLAIN RAIN OVR MUCH OF THE ALLEGHENY PLATEAU AS OF 07Z.
MEANWHILE...FZRA CONTINUES TO FALL ACROSS PORTIONS OF CENTRAL PA.
WHILE AIR TEMPERATURES ARE JUST ABOVE FREEZING...GROUND
TEMPERATURES STILL COLD.

MDL SOUNDINGS...AS WELL AS THE LATEST GUIDANCE...CONTINUE TO
INDICATE THE LOW LVL COLD AIR WILL ERODE FROM WEST TO EAST...WITH
THE LAST OF THE FZRA ENDING ACROSS THE REGION BY SUNRISE.

FAR SW PART OF THE CWA ABOVE FREEZING...KEEPING AN EYE ON THE
RAINFALL...AS WE ALREADY HAVE WATER OVER SOME ROADS AS OF LATE
EVENING.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM THURSDAY/...
SFC FRONTAL BOUNDARY WILL SAG SOUTH OF PA BY LATE WEDNESDAY.
CONCERN IS THAT RATHER COLD AIR AT LOW LEVELS WILL WORK IN...AT
THE SAME TIME THAT ENERGY FROM THE SW WILL RESULT IN MORE PCPN.

MORE DETAILS BELOW.

MODELS CONTINUE TO SHOW AN AMPLIFIED AND MOIST SW FLOW ALOFT AND
JET ENTRANCE REGION DYNAMICS SUPPORTING A BROAD STRIPE OF PCPN
ALONG A WELL DEFINED BAROCLINIC ZONE AHEAD OF PHASING UPPER LEVEL
ENERGY OVER THE DSW/ROCKIES TODAY AND MOVING EWD THROUGH THE OH
VLY AND MID ATLC ON THURSDAY. SEVERAL WAVES OF LOW PRESSURE ARE
FCST TO DEVELOP AND MOVE ENEWD ALONG A SW-NE ORIENTED COLD FRONT
WHICH SHOULD PROGRESS AND SETTLE SEWD THROUGH THE MID ATLC REGION
BY EARLY THURS...AS ARCTIC HIGH PRESSURE BUILDS INTO THE UPPER
PLAINS. AMPLE MOISTURE IS FCST BY THE MODELS TO MOVE INTO A
DEEPENING COLD SECTOR ALONG/NORTH OF THE SEWD-ADVANCING COLD
FRONTAL BOUNDARY WHICH COULD RESULT IN A LATE SEASON HEAVY SNOW
EVENT FOR SOUTH CENTRAL PA WED NGT INTO THURS. THERE ARE MODEL
DIFFERENCES WITH THE TIMING OF THE FRONT WHICH IS LKLY TIED TO THE
CONSOLIDATION OF SHORTWAVE ENERGY UPSTREAM. THAT SAID...THE
CONSENSUS FCST AXIS OF MAX QPF /0.50 INCH OR GREATER/ HAS BEEN
FAIRLY CONSISTENT PAINTED OVER THE SRN 1/3 OF THE CWA. SIMILAR TO
YESTERDAY...USED A MULTI MODEL BLEND WITH PSEUDO BIAS CORRECTION
FACTOR TO DERIVE GRIDDED QPF AMTS WHICH GENERALLY RANGE FROM 0.25
TO 0.75 INCHES ACROSS THE SRN 1/2 OF THE CWA. THE COLUMN WILL BE
IN A STATE OF TRANSITION AND COOLING DOWN FROM NW TO SE WED-WED
NGT AS THE COLD FRONT PUSHES SOUTHEAST ACROSS THE AREA. THIS
SHOULD SUPPORT A TRANSITION FROM RAIN TO SNOW. A PERIOD OF SLEET
MAY IMPACT FCST SNOW ACCUMULATIONS WITH THE DURATION A KEY FACTOR
IN THIS FCST. WITH INCREASING CONFIDENCE AND GREATEST RISK IN THE
POTENTIAL FOR HEAVY SNOW/6+ INCHES...WHICH IS SUPPORTED BY ROBUST
WPC ENSEMBLE AS WELL AS THE GEFS MEAN...HAVE ISSUED A WINTER STORM
WATCH FOR THE SOUTH-CENTRAL COUNTIES FROM WEDNESDAY EVENING
THROUGH THURSDAY EVENING. HOWEVER...LINGERING PRECIP REMAINS
LIKELY ACROSS SOUTHERN PA IN REGION OF 8-7H FGEN FORCING. MDL BLYR
TEMPS INDICATE PRECIP WILL FALL AS LGT RAIN ACROSS THE SOUTHEAST
COUNTIES. HOWEVER...MDL SOUNDINGS JUST COLD ENOUGH TO SUPPORT A
RAIN/SNOW MIX ACROSS THE LAUREL HIGHLANDS...WHERE A LIGHT ACCUM OF
UP TO AN INCH APPEARS POSSIBLE BY WED EVENING. DRIER AIR ACROSS
NORTHERN PA SHOULD TRANSLATE TO A MAINLY DRY DAY THERE WITH JUST A
CHC OF -SHSN.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AN ACTIVE LATE-WINTER PRECIPITATION PATTERN WILL IMPACT CENTRAL
PA THROUGH MIDWEEK FOLLOWED BY WHAT IS HOPEFULLY THE LAST SHOT OF
ARCTIC AIR FOR THE SEASON THURSDAY INTO FRIDAY. THE PATTERN SHOULD
DRY OUT LATE IN THE WEEK THROUGH THE UPCOMING WEEKEND WITH HIGH
PRESSURE IN CONTROL MOST OF THE TIME. THE GENERAL MODEL AND ENSEMBLE
CONSENSUS IS TO MAINTAIN A RIDGE IN THE WEST AND TROUGH IN THE
EAST THROUGH THE WEEKEND WITH SOME SIGNS OF A PATTERN SHIFT BY THE
MIDDLE OF NEXT WEEK WITH TROUGHING FCST TO DEVELOP ALONG THE WEST
COAST. BELOW NORMAL TEMPS SHOULD MODERATE CLOSER TO NORMAL EARLY
NEXT WEEK WITH SOME HINTS AT EVEN WARMER TEMPS LATER NEXT WEEK.

WHAT IS HOPEFULLY THE LAST SHOT OF ARCTIC AIR THIS SEASON SHOULD
ARRIVE BEHIND THE COLD FRONT. FRIDAY MORNING LOWS ARE LKLY TO BE
20-30F BELOW NORMAL WITH SINGLE DIGIT LOWS +/- ZERO DEGREES. SUCH
READINGS MAY BREAK DAILY RECORDS.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
03Z TAFS SENT.

MAINLY RAIN NOW IN MOST AREAS.

EARLIER DISCUSSION BELOW.

A WARM FRONT LIFTING NE FROM THE OH VLY WILL KEEP A LARGE
AREA OF FREEZING RAIN AND SLEET ACROSS MOST OF THE AREA THIS
EVENING. JST WARM ENOUGH FOR JUST RAIN...BUT GROUND AND OBJECT
TEMPS LIKELY STILL COLD. THE OTHER FACTOR OVERNIGHT WILL BE LLWS.

THE PRECIPITATION WILL LIKELY GO OVER TO JUST RAIN LATE TONIGHT
FOR A SHORT TIME. MANY AREAS MAY JUST SEE NOTHING ONCE THE
STRONGER WARM ADVECTION SHUTS OFF.

FOR WED...RAIN WILL GO BACK TO SNOW FROM NW TO SE. HARD TO SEE
CONDITIONS BEING VERY GOOD.

VERY COLD LOW LEVEL AIR WILL BE ADVECTED BACK TO THE SOUTH LATE
WED INTO THU. A SERIES OF WEAK LOW PRESSURE SYSTEMS WILL TRACK
ALONG THE COLD FRONT FROM LATE WED INTO THU...LIKELY GIVING
AT LEAST SOUTHERN PA SOME SNOW. THE COMBINATION OF INCREASING
WINDS...SNOW...AND FALLING TEMPERATURES WILL LIKELY RESULT IN
POOR CONDITIONS FOR AVIATION.

IMPROVING CONDITIONS WILL SET IN FOR FRIDAY INTO MONDAY...AS COLD
HIGH PRESSURE BUILDS INTO THE AREA.

OUTLOOK...

WED NIGHT...SIG REDUCTIONS IN SNOW DEVELOPING MAINLY ACROSS THE
SOUTH.

THU...SLOWLY IMPROVING CONDITIONS...LINGERING MVFR NW AND SE.

FRI-SAT...MAINLY VFR.

SUN...MVFR WITH CHC -SHSN MAINLY NORTH AND WEST. VFR SE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR PAZ006-
011-012-017>019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY EVENING
FOR PAZ024>028-033>036-056>059-063>066.

&&

SYNOPSIS...FITZGERALD/MARTIN
NEAR TERM...FITZGERALD/MARTIN
SHORT TERM...FITZGERALD/MARTIN/STEINBUGL
LONG TERM...MARTIN/STEINBUGL
AVIATION...MARTIN
Hazardous weather outlook, Mar 4, 1:30 AM EST, 1 hour 32 minutes before
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The office that day

Everything else NWS State College, PA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 3, 10:39 PM ESTAreal Flood AdvisoryCTPBedford, Blair, Cambria, Clearfield, Somerset4 hr
Mar 4, 2:28 AM ESTAreal Flood AdvisoryCTPBedford, Blair, Cambria, Clearfield, Somerset16 hr
Mar 4, 4:13 AM ESTWinter Storm WarningCTPAdams, Bedford, Blair, Cambria, Cumberland, Dauphin and 11 more39 hr
Mar 4, 5:24 AM ESTAreal Flood WarningCTPCambria6 hr
Mar 4, 9:41 AM ESTWinter Weather AdvisoryCTPBedford, Blair, Cambria, Centre, Clearfield, Columbia and 14 more30 hr
Mar 4, 2:59 PM ESTRiver Flood WarningCTPSomerset7 hr
Mar 4, 6:42 PM ESTAreal Flood AdvisoryCTPSomerset3 hr

Nearby

Flood Watches in Pennsylvania, 2015Every flood watch in 2015

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.