New York, NY...Philadelphia, PA...Baltimore, MD...Washington, DC...Virginia Beach, VA...
Probabilistic Tornado Graphic
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
2 %
22,015
7,570,058
Baltimore, MD...Washington, DC...Arlington, VA...Alexandria, VA...Spring Hill, FL...
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
New York, NY...Philadelphia, PA...Baltimore, MD...Washington, DC...Virginia Beach, VA...
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
SPC AC 121252
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT SAT SEP 12 2015
VALID 121300Z - 131200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF NRN AND CNTRL
FL...
...THERE IS A MRGL RISK OF SVR TSTMS FROM THE ERN CAROLINAS INTO THE
MID-ATLANTIC STATES...
...SUMMARY...
A FEW STORMS WITH DAMAGING WIND MAY AFFECT PARTS OF CENTRAL AND
NORTHERN FLORIDA TODAY. ISOLATED STRONG TO PERHAPS LOCALLY SEVERE
THUNDERSTORMS MAY OCCUR FROM THE EASTERN CAROLINAS INTO THE
MID-ATLANTIC TODAY AND TONIGHT.
...SYNOPTIC SETUP...
MID-MS/LWR OH VLY TROUGH WILL FURTHER AMPLIFY AS IT CONTINUES SLOWLY
E THIS PERIOD...WHILE WRN U.S. RIDGE IS SLIGHTLY SUPPRESSED BY
DISTURBANCES IN FAST WLY FLOW OVER SW CANADA. MAIN VORT MAX
ASSOCIATED WITH MS-OH VLY SYSTEM...NOW OVER ERN IA...SHOULD MOVE SSE
INTO WRN TN THIS EVE...BEFORE TURNING E INTO WRN NC EARLY SUN. AT
THE SAME TIME...SEVERAL WEAK DISTURBANCES WILL TRACK NE IN
SLOWLY-PROGRESSIVE SRN STREAM JET THAT ATTM EXTENDS FROM THE NRN
GULF OF MEXICO TO ERN NC.
LOOSELY-ORGANIZED SFC LOW NOW OVER CNTRL VA SHOULD BECOME BETTER-
DEFINED AS IT DEVELOPS NNE INTO CNTRL MD AND PA LATER
TODAY/TNGT...AND INTO UPSTATE NY EARLY SUN. ALTHOUGH A SHALLOW WARM
FRONT SHOULD ADVANCE N ACROSS THE CHESAPEAKE BAY REGION IN
RESPONSE...THE MAIN WARM FRONT/LEADING EDGE OF TRUE TROPICAL AIR
LIKELY WILL REMAIN JUST OFF THE MID-ATLANTIC CST IN ASSOCIATION WITH
THE SRN STREAM JET. A SECONDARY SFC LOW FORMING ALONG THIS BOUNDARY
MAY APPROACH CAPE COD LATE IN THE PERIOD.
...NRN/CNTRL FL TODAY...
PROXIMITY OF SRN STREAM JET WILL MAINTAIN SEASONABLY
STRONG...UNIDIRECTIONAL...WSW FLOW ACROSS THE REGION THROUGH THIS
EVE. WHILE MID-LVL LAPSE RATES WILL REMAIN WEAK AND CLOUDS/EXISTING
SHOWERS WILL LIMIT SFC HEATING...BUOYANCY WILL BE AUGMENTED BY PW
AOA 2.00 INCHES. SATELLITE SUGGESTS LITTLE CHANGE IN NEUTRAL
LARGE-SCALE FORCING FOR ASCENT THROUGH THE DAY. NEVERTHELESS...GIVEN
RICH MOISTURE AND 40+ KT MID-LVL FLOW...SETUP MAY FOSTER SHORT
LINES/CLUSTERS OF STORMS WITH EMBEDDED SMALL BOWS CAPABLE OF DMGG
GUSTS AND PERHAPS A BRIEF TORNADO OVER NRN AND CNTRL FL.
...ERN CAROLINAS TO MID-ATLANTIC TODAY/TNGT...
GIVEN 40-50 KT SWLY 500 MB FLOW ON ERN SIDE OF APPROACHING
TROUGH...AMPLE DEEP SHEAR WILL EXIST FOR ORGANIZED/SUSTAINED STORMS
OVER THE CAROLINAS AND MID-ATLANTIC TODAY AND TNGT. THE CONVECTIVE
FCST...HOWEVER...IS COMPLICATED BY THE FACT THAT STRONGEST FORCING
FOR ASCENT WILL REMAIN WELL TO THE WEST /OVER THE OH-TN VLYS/ IN
ASSOCIATION WITH MIDWEST UPR VORT...MID-LVL LAPSE RATES WILL BE
WEAK...AND BECAUSE THE RICHEST LOW-LVL MOISTURE WILL REMAIN LARGELY
OFFSHORE /BENEATH AXIS OF SRN STREAM JET/.
ALREADY THIS MORNING...MODEST WAA/MOISTURE TRANSPORT ATOP SHALLOW
COOL DOME HAVE SUPPORTED TRANSIENT SUPERCELLS OVER SRN/ERN VA. THIS
ACTIVITY MAY PERSIST AND SPREAD NE ACROSS THE CHESAPEAKE
BAY/DELMARVA PENINSULA THROUGH MIDDAY...POSING A RISK FOR ISOLD
LOCALLY DMGG WIND...MARGINALLY SVR HAIL...AND A BRIEF TORNADO.
ADDITIONAL SHOWERS/STORMS SHOULD FORM WITH DAYTIME HEATING FARTHER
TO THE W ...ALONG SLOWLY-STRENGTHENING COLD FRONT NOW EMERGING FROM
THE WRN MD/VA MOUNTAINS. THE CONVECTION LIKELY WILL MERGE INTO ONE
OR MORE BROKEN LINES THAT MOVE EWD...WHILE DEVELOPING BOTH SWD INTO
NC AND NNEWD INTO PA/NJ. LOCALLY DMGG GUSTS COULD ACCOMPANY SOME
STORMS. A STRONG STORM OR TWO ALSO COULD GLANCE THE CAPE COD AREA
LATE IN THE PERIOD. OVERALL...HOWEVER...MODEST BUOYANCY SHOULD LIMIT
SVR THREAT FROM THE CAROLINAS TO NY/FAR SRN NEW ENGLAND.
...CNTRL/NRN FL TODAY...
PROXIMITY OF SRN STREAM JET WILL MAINTAIN SEASONABLY
STRONG...UNIDIRECTIONAL...WSW FLOW ACROSS THE REGION THROUGH THIS
EVE. WHILE MID-LVL LAPSE RATES WILL REMAIN WEAK AND CLOUDS/EXISTING
SHOWERS WILL LIMIT SFC HEATING...BUOYANCY WILL BE AUGMENTED BY PW
AOA 2.00 INCHES. SATELLITE SUGGESTS LITTLE CHANGE IN NEUTRAL
LARGE-SCALE FORCING FOR ASCENT THROUGH THE DAY. NEVERTHELESS...GIVEN
RICH MOISTURE AND 40+ KT MID-LVL FLOW...SETUP MAY FOSTER SHORT
LINES/CLUSTERS OF STORMS WITH EMBEDDED SMALL BOWS CAPABLE OF A FEW
LOCALLY DMGG GUSTS OVER CNTRL AND PERHAPS NRN FL.
...SRN HIGH PLNS LATE AFTN/EVE...
ENHANCED NWLY MID-LVL FLOW ASSOCIATED WITH AMPLIFYING MS-OH VLY UPR
SYSTEM WILL STRENGTHEN LEE TROUGH/LOW-LVL MOISTURE RETURN OVER THE
SRN HIGH PLNS TODAY. COUPLED WITH STRONG SFC HEATING AND STEEP LOW-
TO MID-LVL LAPSE RATES...ISOLD TO WDLY SCTD AFTN/EVE STORMS MAY FORM
OVER NE NM AND PERHAPS THE OK-TX PANHANDLES. WHILE THESE COULD YIELD
A SPOT OR TWO OF HAIL...NEUTRAL TO NEGATIVE LARGE-SCALE FORCING FOR
ASCENT SHOULD LIMIT STORM COVERAGE...AND SVR THREAT.
..CORFIDI/COOK.. 09/12/2015
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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