Storm Prediction Forecasts
No watches are valid as of Fri Sep 3 19:38:04 UTC 2010.
No Mesoscale Discussions are in effect as of Fri Sep 3 19:38:05 UTC 2010.
SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1134 AM CDT FRI SEP 03 2010
VALID 041200Z - 051200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A LARGE UPPER TROUGH WILL PIVOT OUT OF THE OH VALLEY AND INTO THE
NERN STATES WHICH WILL PUSH A COLD FRONT WELL OFFSHORE INTO THE WRN
ATLANTIC. THIS FRONT WILL TRAIL SWWD INTO NRN FL/SRN GA WITH
ISOLATED THUNDERSTORMS POSSIBLE S OF THE BOUNDARY WITH MINIMAL
INSTABILITY. TO THE W...AN UPPER RIDGE EXTENDING FROM UT INTO ERN MT
WILL FLATTEN AS A TROUGH SINKS SWD OUT OF WRN CANADA. WEAK SURFACE
CONVERGENCE ASSOCIATED WITH A COLD FRONT ALONG WITH HEIGHT FALLS
ALOFT WILL RESULT IN SCATTERED THUNDERSTORMS WITH GUSTY WINDS
POSSIBLE OVER CNTRL AND WRN MT.
...MT...
SCATTERED STORMS WILL DEVELOP BY MID AFTERNOON ACROSS WRN MT ALONG A
COLD FRONT. STEEP LOW TO MID LEVEL LAPSE RATES WILL EXIST DUE TO
STRONG HEATING AND COOLING ALOFT. GIVEN 40-60 KT MID TO UPPER LEVEL
FLOW AND INVERTED-V PROFILES...SOME STORMS MAY BE CAPABLE OF STRONG
TO SEVERE WIND GUSTS BEFORE CIN INCREASES AFTER SUNSET.
..JEWELL.. 09/03/2010
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SPC 2000Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0235 PM CDT FRI SEP 03 2010
VALID 032000Z - 041200Z
...NO SVR TSTM AREAS FORECAST...
SEVERE ASPECT OF PREVIOUS OUTLOOK REQUIRES NO CHANGES. REMOVED SW TX
FROM THUNDER AS DRIER AIR CONTINUES TO WORK SWWD INTO THAT REGION.
..JEWELL.. 09/03/2010
.PREV DISCUSSION... /ISSUED 1114 AM CDT FRI SEP 03 2010/
...SYNOPSIS...
A PRONOUNCED MIDLEVEL TROUGH OVER THE UPPER GREAT LAKES WILL
PROGRESS EWD OVER THE UPPER OH VALLEY AND LOWER GREAT LAKES THROUGH
TONIGHT. AN ASSOCIATED SURFACE COLD FRONT WILL MOVE EWD ACROSS THE
APPALACHIANS AND SWD TO NEAR THE GULF COAST BY THE END OF THE
PERIOD. MEANWHILE...HURRICANE EARL WILL BEGIN TO ACCELERATE NNEWD
AND THE WRN PORTION OF THE WEAKENING STORM CORE WILL SKIRT THE SE
NEW ENGLAND COAST TONIGHT.
SCATTERED THUNDERSTORMS ARE EXPECTED ALONG THE COLD FRONT THIS
AFTERNOON FROM SE TX NEWD ACROSS THE TN VALLEY AND APPALACHIANS.
REGIONAL 12Z SOUNDINGS REVEALED RATHER POOR MIDLEVEL LAPSE RATES IN
THE NARROW MOIST WARM SECTOR...WITH MARGINAL INSTABILITY EXPECTED
THIS AFTERNOON ACROSS THE UPPER OH AND TN VALLEYS...AND MORE
SUBSTANTIAL CAPE ACROSS TX IN THE PLUME OF 2.25-2.50 INCH
PRECIPITABLE WATER. GIVEN ONLY WEAK INSTABILITY AND RATHER MODEST
LOW-MIDLEVEL FLOW/SHEAR IN THE WARM SECTOR ACROSS THE OH
VALLEY...THE POTENTIAL FOR DAMAGING WINDS APPEARS TOO MARGINAL TO
WARRANT MAINTAINING EVEN 5% WIND PROBABILITIES. FARTHER
N...ISOLATED STRONG STORMS MAY OCCUR THIS AFTERNOON ACROSS NRN MAINE
ALONG A SLOW-MOVING WARM FRONT. VERTICAL SHEAR WILL BE AT LEAST
MARGINALLY FAVORABLE FOR SUPERCELLS...THOUGH RATHER WARM PROFILES
ALOFT AND RESULTANT MODEST INSTABILITY...ALONG WITH ONLY MODEST
LOW-LEVEL FLOW...SUGGEST THAT ANY PARTICULAR TYPE OF SEVERE THREAT
SHOULD REMAIN QUITE LIMITED.
OTHERWISE...A FEW DIURNAL THUNDERSTORMS WILL OCCUR WITHIN THE
TROPICAL MOISTURE PLUME ACROSS S FL...AND POTENTIALLY ALONG THE NRN
FRINGE OF THE SUBTROPICAL MOISTURE PLUME INTO SE AZ/SW NM. ISOLATED
THUNDERSTORMS WILL ALSO BE POSSIBLE FROM INTERIOR ORE NEWD ACROSS
THE NRN ROCKIES WITHIN A WEAK MIDLEVEL MOISTURE PLUME AND IN ADVANCE
OF A LOW-AMPLITUDE SHORTWAVE TROUGH APPROACHING WA.
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SPC 1630Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1114 AM CDT FRI SEP 03 2010
VALID 031630Z - 041200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A PRONOUNCED MIDLEVEL TROUGH OVER THE UPPER GREAT LAKES WILL
PROGRESS EWD OVER THE UPPER OH VALLEY AND LOWER GREAT LAKES THROUGH
TONIGHT. AN ASSOCIATED SURFACE COLD FRONT WILL MOVE EWD ACROSS THE
APPALACHIANS AND SWD TO NEAR THE GULF COAST BY THE END OF THE
PERIOD. MEANWHILE...HURRICANE EARL WILL BEGIN TO ACCELERATE NNEWD
AND THE WRN PORTION OF THE WEAKENING STORM CORE WILL SKIRT THE SE
NEW ENGLAND COAST TONIGHT.
SCATTERED THUNDERSTORMS ARE EXPECTED ALONG THE COLD FRONT THIS
AFTERNOON FROM SE TX NEWD ACROSS THE TN VALLEY AND APPALACHIANS.
REGIONAL 12Z SOUNDINGS REVEALED RATHER POOR MIDLEVEL LAPSE RATES IN
THE NARROW MOIST WARM SECTOR...WITH MARGINAL INSTABILITY EXPECTED
THIS AFTERNOON ACROSS THE UPPER OH AND TN VALLEYS...AND MORE
SUBSTANTIAL CAPE ACROSS TX IN THE PLUME OF 2.25-2.50 INCH
PRECIPITABLE WATER. GIVEN ONLY WEAK INSTABILITY AND RATHER MODEST
LOW-MIDLEVEL FLOW/SHEAR IN THE WARM SECTOR ACROSS THE OH
VALLEY...THE POTENTIAL FOR DAMAGING WINDS APPEARS TOO MARGINAL TO
WARRANT MAINTAINING EVEN 5% WIND PROBABILITIES. FARTHER
N...ISOLATED STRONG STORMS MAY OCCUR THIS AFTERNOON ACROSS NRN MAINE
ALONG A SLOW-MOVING WARM FRONT. VERTICAL SHEAR WILL BE AT LEAST
MARGINALLY FAVORABLE FOR SUPERCELLS...THOUGH RATHER WARM PROFILES
ALOFT AND RESULTANT MODEST INSTABILITY...ALONG WITH ONLY MODEST
LOW-LEVEL FLOW...SUGGEST THAT ANY PARTICULAR TYPE OF SEVERE THREAT
SHOULD REMAIN QUITE LIMITED.
OTHERWISE...A FEW DIURNAL THUNDERSTORMS WILL OCCUR WITHIN THE
TROPICAL MOISTURE PLUME ACROSS S FL...AND POTENTIALLY ALONG THE NRN
FRINGE OF THE SUBTROPICAL MOISTURE PLUME INTO SE AZ/SW NM. ISOLATED
THUNDERSTORMS WILL ALSO BE POSSIBLE FROM INTERIOR ORE NEWD ACROSS
THE NRN ROCKIES WITHIN A WEAK MIDLEVEL MOISTURE PLUME AND IN ADVANCE
OF A LOW-AMPLITUDE SHORTWAVE TROUGH APPROACHING WA.
..THOMPSON/PETERS.. 09/03/2010
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SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1151 AM CDT FRI SEP 03 2010
VALID 031700Z - 041200Z
...NO CRITICAL AREAS...
...N-CNTRL/NERN ORE...SERN WA...
NO CHANGES MADE TO THE PREVIOUS FORECAST.
...PIEDMONT OF THE CAROLINAS INTO CNTRL VA...
MODIFIED 12Z RAOBS ACROSS THE REGION AS WELL AS GPS TPW GUIDANCE
CONFIRM THE PRESENCE OF DRY AIR W-SW OF TC EARL SUPPORTIVE OF LOW
AFTERNOON RH VALUES /AOB 25 PERCENT/ ACROSS THE PIEDMONT OF THE
CAROLINAS INTO CNTRL VA. HOWEVER...AS MENTIONED IN PREVIOUS D1
FORECAST...MODEL GUIDANCE CONTINUES TO INDICATE WLY SUSTAINED WIND
SPEEDS AOB 15 MPH DURING MUCH OF THE AFTERNOON...MITIGATING A MORE
SUBSTANTIAL FIRE WEATHER THREAT.
...NRN FL AND THE PANHANDLE...
AS SURFACE TEMPERATURES WARM TO AROUND 90 F DURING THE
AFTERNOON...AND DEWPOINTS MIX DOWN TO NEAR 60 F...MIN RH VALUES WILL
FALL TO 35 PERCENT. HOWEVER...ALL MODEL GUIDANCE SHOWS SUSTAINED
WIND SPEEDS AOB 5 MPH...WHICH WILL PRECLUDE CRITICAL FIRE WEATHER
CONDITIONS FROM DEVELOPING.
...PORTIONS OF CNTRL AND SRN AZ...
MODEL FORECAST SOUNDINGS AS WELL AS MODIFIED 12Z TUS RAOB INDICATE
DEEP INVERTED-V THERMODYNAMIC PROFILES WILL BE POSSIBLE FOR
LOCATIONS OVER CNTRL AND SRN AZ THAT CAN APPROACH 100 F DURING THE
AFTERNOON...SUGGESTING SOME POTENTIAL EXISTS FOR DRY THUNDERSTORMS.
HOWEVER...COMBINATION OF INCREASING PWAT VALUES /RANGING FROM 0.60
INCHES OVER CNTRL AZ TO NEAR 1 INCH OVER SRN AZ/ AND SLOW FORECAST
STORM MOTIONS MAY MITIGATE THAT THREAT SOMEWHAT...RESULTING IN A
MIXTURE OF WET AND DRY STORMS.
..GARNER.. 09/03/2010
.PREV DISCUSSION... /ISSUED 0322 AM CDT FRI SEP 03 2010/
...SYNOPSIS...
A LARGE-SCALE UPPER-LEVEL TROUGH WILL PROGRESS EWD ACROSS THE GREAT
LAKES/MIDWEST...WHILE AN UPSTREAM RIDGE SHIFTS FROM THE PACIFIC NW
TO THE NRN ROCKIES. AN UPPER-LEVEL SHORT WAVE TROUGH WILL REACH THE
SRN BRITISH COLUMBIA COAST BY EARLY SAT.
...N-CNTRL/NERN ORE...SERN WA...
WEAK MID-LEVEL INSTABILITY MAY DEVELOP DURING THE LATE
AFTERNOON/EVENING AS MODEST HEIGHT FALLS AND DIFFLUENT UPPER-LEVEL
FLOW OVERSPREAD THE REGION DOWNSTREAM OF THE SHORT WAVE TROUGH
APPROACHING SRN BRITISH COLUMBIA. LATEST MODEL FORECASTS DIFFER WITH
THE DEGREE OF DESTABILIZATION WITH THE NAM AND ITS COMPANION HI-RES
WRF-NMM MORE AGGRESSIVE THAN OTHER DETERMINISTIC AND ENSEMBLE
GUIDANCE. GIVEN THE EXPECTATION OF RELATIVELY WEAK
FORCING/MOISTENING...OVERALL TSTM PROBABILITIES SHOULD REMAIN LOW
/AROUND 10 PERCENT/. HOWEVER...SHOULD ANY TSTMS DEVELOP THEY OUGHT
TO BE MAINLY DRY WITH THE PRESENCE OF DEEP INVERTED-V THERMODYNAMIC
PROFILES AND FAST STORM MOTIONS. NEVERTHELESS...FUEL DRYNESS LEVELS
IN THE MOIST CATEGORY /PER LATEST NWCC OUTLOOK/ WITH RECENT
ABOVE-NORMAL RAINFALL OVER PORTIONS OF THE AREA WILL MITIGATE THE
THREAT.
...PIEDMONT OF THE CAROLINAS INTO S-CNTRL VA...
A CORRIDOR OF RELATIVELY LOWER PW VALUES WAS SAMPLED IN 06Z
PIT/RNK/FFC RAOBS...BETWEEN AREAS OF RICHER MOISTURE ASSOCIATED WITH
TC EARL AND A WRN GREAT LAKES UPPER-LEVEL TROUGH. THIS DRY AIR
CORRIDOR WILL SHIFT EWD AND BE CENTERED ACROSS THE PIEDMONT BY EARLY
AFTERNOON. WELL ABOVE-NORMAL TEMPERATURES IN THE MIDDLE TO UPPER 90S
SHOULD LEAD TO LOW RH VALUES /FROM 18 TO 25 PERCENT/. HOWEVER...WLY
SURFACE WINDS WILL REMAIN MODERATE /AROUND 8 TO 15 MPH/ AND LIMIT A
MORE SUBSTANTIAL THREAT.
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
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SPC Day 2 Fire Weather Outlook
DAY 2 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0159 PM CDT FRI SEP 03 2010
VALID 041200Z - 051200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF S-CNTRL/SERN ID...FAR
NERN NV...
...PORTIONS OF S-CNTRL/SERN ID...FAR NERN NV...
NO CHANGES MADE TO THE PREVIOUS FORECAST.
...LEE OF THE NRN SIERRAS IN FAR NERN CA/NWRN NV...
NO CHANGES MADE TO THE PREVIOUS FORECAST.
...PORTIONS OF CNTRL/SRN WY...
A LOW AMPLITUDE MID-LEVEL RIDGE AXIS IS FORECAST TO MOVE EWD ACROSS
CNTRL/SRN WY ON SATURDAY...ALLOWING STRENGTHENING WLY UPPER-LEVEL
FLOW FIELDS TO SPREAD ACROSS THE REGION. AS THIS TAKES PLACE...MODEL
FORECAST GUIDANCE INDICATES SUSTAINED WINDS WILL APPROACH 20
MPH...WITH GUSTS UP TO 30 MPH. THESE WINDS COMBINED WITH MIN RH
VALUES AOB 15 PERCENT WILL LEAD TO ELEVATED FIRE WEATHER CONDITIONS.
...PIEDMONT OF THE CAROLINAS AND S-CNTRL VA...
NAM FORECAST GUIDANCE INDICATES THAT DRY AIR WILL BE MAINTAINED
ACROSS S-CNTRL VA INTO THE PIEDMONT OF THE CAROLINAS ON
SATURDAY...FAVORING AFTERNOON RH VALUES AOB 30 PERCENT. GIVEN THE
PRESENCE OF A SEASONABLY STRONG UPPER TROUGH AND ASSOCIATED UPPER
JET OVER THE MID ATLANTIC REGION...WLY SURFACE WINDS SUSTAINED AT 15
MPH WILL BE POSSIBLE OVER VA/NC...WHILE WEAKER SPEEDS ARE
ANTICIPATED OVER SC /AOB 10 MPH/.
..GARNER.. 09/03/2010
.PREV DISCUSSION... /ISSUED 0457 AM CDT FRI SEP 03 2010/
...SYNOPSIS...
AN UPPER-LEVEL TROUGH WILL AMPLIFY FROM SWRN CANADA ACROSS THE
PACIFIC NW. A BELT OF MODERATELY STRONG W/SWLY MID-LEVEL FLOW WILL
BECOME ESTABLISHED FROM NRN CA ACROSS THE NRN GREAT BASIN BY SAT
AFTERNOON.
...PORTIONS OF S-CNTRL/SERN ID...FAR NERN NV...
MARGINAL TO LOW-END CRITICAL CONDITIONS SHOULD DEVELOP SAT AFTERNOON
AS W/SWLY MID-LEVEL FLOW STRENGTHENS ATOP A DEEPLY MIXED BOUNDARY
LAYER. SUSTAINED SURFACE WINDS SHOULD REACH 15 TO 25 MPH...AS RH
VALUES BECOME RATHER LOW /BETWEEN 5 AND 10 PERCENT/. THE ERN EXTENT
OF THE THREAT IN SERN ID WILL BE SUBDUED BY RECENT ABOVE-NORMAL
RAINFALL.
...LEE OF THE NRN SIERRAS IN FAR NERN CA/NWRN NV...
LOCALIZED CRITICAL CONDITIONS MAY DEVELOP ALONG THE LEE OF THE NRN
SIERRAS. ALTHOUGH THE MAGNITUDE OF MID-LEVEL FLOW WILL BE SIMILAR TO
THE AFOREMENTIONED CRITICAL AREA...MODEL FORECAST SOUNDINGS INDICATE
SLIGHTLY WARMER MID-LEVEL TEMPERATURES RESULTING IN LOWER MIXING
HEIGHTS. THIS SHOULD HELP HOLD SUSTAINED SURFACE SPEEDS TO AROUND 12
TO 20 MPH. NEVERTHELESS...THIS WILL BE JUXTAPOSED WITH VERY LOW RH
VALUES OF 3 TO 8 PERCENT.
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
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