Storm Prediction Center Forecast
RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sat Sep 4 10:58:02 UTC 2010.
No Mesoscale Discussions are in effect as of Sat Sep 4 10:58:02 UTC 2010.
Day 4-8 Outlook
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0351 AM CDT SAT SEP 04 2010
VALID 071200Z - 121200Z
...DISCUSSION...
AS GOOD AGREEMENT CONTINUES AMONG LATEST ECMWF/GEFS GUIDANCE...IT IS
LIKELY THAT A RELATIVELY MORE ACTIVE PATTERN WILL DEVELOP ACROSS THE
NORTH CENTRAL STATES DURING THE MIDDLE TO LATTER PART OF NEXT WEEK.
THIS WILL BE IN ASSOCIATION WITH THE EASTWARD ADVANCEMENT OF A
WESTERN STATES UPPER TROUGH...ALONG WITH THE ANTICIPATED
AVAILABILITY OF A BROAD/HIGHER QUALITY MOIST SECTOR GIVEN A
STALLING/RETREATING CENTRAL STATES FRONT DURING THE MIDDLE PART OF
THE WEEK. INITIALLY...IT APPEARS THAT SOME SEVERE RISK MAY EXIST ON
DAY 5/WEDNESDAY ACROSS THE NORTH-CENTRAL HIGH PLAINS. A MORE
APPRECIABLE SEVERE RISK SHOULD UNFOLD INTO DAYS 6/7...MAINLY THE
DAKOTAS AND WESTERN/NORTHERN NEB ON DAY 6/THURSDAY...AND PERHAPS THE
UPPER MS RIVER VALLEY ON DAY 7/FRIDAY. WHILE CURRENT THINKING IS
THAT CATEGORICAL SLIGHT RISKS WILL ULTIMATELY BE WARRANTED IN THIS
TIME FRAME...LARGE SCALE TIMING UNCERTAINTY/INHERENT UNKNOWNS
CURRENTLY PRECLUDE DELINEATION OF ANY HIGHER PROBABILITY /30 PERCENT
AND GREATER/ SEVERE RISK AREAS.
Read more
SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT SAT SEP 04 2010
VALID 041200Z - 051200Z
...CRITICAL FIRE WEATHER AREA FOR S-CNTRL ID...NERN NV...
...SYNOPSIS...
AN UPPER-LEVEL TROUGH WILL AMPLIFY FROM BRITISH COLUMBIA INTO THE
PACIFIC NW THROUGH EARLY SUN...AS A DOWNSTREAM RIDGE MOVES FROM THE
NRN ROCKIES TO THE NRN PLAINS. A WEAK MID-LEVEL IMPULSE JUST OFF THE
SWRN ORE COAST WILL PROGRESS INLAND REACHING THE NRN GREAT BASIN
THIS AFTERNOON. IN THE EAST...SEVERAL IMPULSES EMBEDDED WITHIN A
LARGE-SCALE UPPER-LEVEL TROUGH CENTERED OVER THE GREAT LAKES/MIDWEST
WILL EJECT ACROSS THE NRN/CNTRL APPALACHIANS THROUGH NEW ENGLAND.
...S-CNTRL ID...NERN NV...
THE APPROACH OF A WEAK MID-LEVEL IMPULSE OFF THE SWRN ORE COAST AND
ASSOCIATED SPEED MAX WILL BE FAVORABLY TIMED WITH THE DIURNAL
HEATING CYCLE AND SHOULD RESULT IN AREAS OF LOW-END CRITICAL
CONDITIONS. DEEP VERTICAL MIXING WILL PROMOTE SUSTAINED SURFACE
WINDS NEAR 20 MPH WITH GUSTS OF 30 TO 35 MPH...AS RH VALUES BECOME
LOW /BETWEEN 6 AND 12 PERCENT/.
...SERN ID...SRN WY...
EAST OF THE CRITICAL AREA IN S-CNTRL ID...SIMILAR METEOROLOGICAL
CONDITIONS ARE EXPECTED TO EXTEND ACROSS SERN ID INTO SWRN WY.
HOWEVER...ABOVE-NORMAL RAINFALL DURING THE PAST WEEK SHOULD HELP
MARGINALIZE THE OVERALL THREAT. ACROSS SERN WY...RECENT RAINFALL HAS
BEEN LACKING...BUT WIND SPEEDS SHOULD REMAIN SLIGHTLY MORE MODERATE
/AROUND 15 TO 20 MPH/ AND THIS WILL PRECLUDE A CRITICAL AREA
DELINEATION ATTM.
...PIEDMONT AND COASTAL PLAIN OF THE MID-ATLANTIC INTO NC...
MARGINAL TO LOCALIZED CRITICAL CONDITIONS SHOULD DEVELOP THIS
AFTERNOON IN THE WAKE OF A COLD FRONT PASSAGE LATE FRI INTO EARLY
SAT. WLY LOW-LEVEL FLOW WILL BE STRONG OVER THE UPPER
MID-ATLANTIC/NORTHEAST AND PROGRESSIVELY WEAKEN WITH SRN EXTENT
WHERE THE PRESSURE GRADIENT WILL BECOME MORE RELAXED. SUSTAINED
SURFACE WINDS SHOULD RANGE FROM 15 TO 25 MPH N TO BETWEEN 10 TO 15
MPH S. MEANWHILE...WARM/DRY CONDITIONS WILL OCCUR OVER NC/SRN
VA...WHERE RH VALUES SHOULD FALL INTO THE 20S. PROGRESSIVELY
COOLER/MORE MOIST CONDITIONS ARE EXPECTED WITH NWD EXTENT...WITH RH
VALUES LARGELY IN THE 30S. THE RELATIVELY GREATEST THREAT SHOULD
EXIST OVER PORTIONS OF NRN/CNTRL VA WHERE MODERATE TO SEVERE DROUGHT
PERSISTS.
...E-CNTRL NV...W-CNTRL/SWRN UT...
ALTHOUGH THIS REGION WILL REMAIN ON THE SRN PERIPHERY OF STRONGER
MID-LEVEL FLOW ASSOCIATED WITH THE IMPULSE OFF THE SWRN ORE
COAST...DEEP BOUNDARY LAYER MIXING WILL SUPPORT SUSTAINED SURFACE
WINDS OF 15 TO 20 MPH WITH GUSTS OF 25 TO 30 MPH. THIS WILL BE
JUXTAPOSED WITH VERY LOW RH VALUES OF 4 TO 8 PERCENT AND SHOULD
RESULT IN AN ENHANCED FIRE WEATHER THREAT.
...LEE OF THE NRN SIERRAS IN FAR NERN CA/NWRN NV...
LOCALIZED MARGINAL CONDITIONS SHOULD DEVELOP DURING THE LATE
AFTERNOON 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 CONTINUE TO INDICATE THAT THE DEPTH
OF VERTICAL MIXING WILL REMAIN LOWER. THIS SHOULD HELP HOLD
SUSTAINED SURFACE SPEEDS TO AROUND 15 MPH WITH GUSTS OF 25 MPH...AS
RH VALUES FALL TO BETWEEN 5 TO 10 PERCENT.
..GRAMS.. 09/04/2010
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
Read more
SPC Day 2 Fire Weather Outlook
DAY 2 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0458 AM CDT SAT SEP 04 2010
VALID 051200Z - 061200Z
...CRITICAL FIRE WEATHER AREA FOR MOST OF THE ERN GREAT BASIN TO THE
CNTRL ROCKIES...
...SYNOPSIS...
A LARGE-SCALE UPPER-LEVEL TROUGH WILL CONTINUE TO DIG ACROSS THE
NWRN CONUS AND PROGRESS EWD TOWARDS THE NRN/CNTRL ROCKIES THROUGH
EARLY MON. MID-LEVEL WLYS WILL STRENGTHEN WITH A BELT OF 50 TO 70
MPH FLOW AT 500 MB CENTERED ACROSS NRN NV/SRN ID INTO WY ON SUN
AFTERNOON. AT THE SURFACE...A SHARP COLD FRONT WILL SWEEP SWD
THROUGH THE GREAT BASIN...WITH TIGHT THERMAL AND PRESSURE GRADIENTS
DEVELOPING IN ITS WAKE.
...MOST OF THE ERN GREAT BASIN TO THE CNTRL ROCKIES...
WIDESPREAD CRITICAL CONDITIONS APPEAR LIKELY SUN AFTERNOON AHEAD OF
A SHARP COLD FRONT ACROSS NRN AZ...SRN/ERN UT...NRN/WRN CO AND
CNTRL/SRN WY. SUSTAINED SURFACE WINDS WILL INCREASE TO 20 TO 30
MPH...WITH WIND GUSTS LOCALLY REACHING 40 TO 50 MPH OVER PORTIONS OF
SRN WY/NWRN CO. THIS WILL COINCIDE WITH AN ANTECEDENT VERY WARM/DRY
AIR MASS /RH VALUES OF 5 TO 15 PERCENT/.
THE CRITICAL AREA HAS BEEN EXTENDED FARTHER NW INTO NERN NV/NWRN
UT/SERN ID. HERE...STRONG SURFACE WINDS /FROM 20 TO 30 MPH/ DURING
THE AFTERNOON WILL PERSIST INTO THE EVENING AS THE POST-FRONTAL
PRESSURE GRADIENT STRENGTHENS. DESPITE COOLING TEMPERATURES WITH
WINDS VEERING TO THE N/NW...CONSENSUS OF MODEL FORECASTS SUGGESTS RH
RECOVERY WILL INITIALLY BE POOR DURING THE EARLY EVENING AS GUSTS
AOA 30 MPH CONTINUE. ALTHOUGH MIN RH VALUES MAY BE MARGINAL /AROUND
15 PERCENT/...THE STRENGTH AND DURATION OF WINDS WARRANT A CRITICAL
DELINEATION.
...PORTIONS OF THE TX/OK PANHANDLES...SWRN KS...NWRN OK...
MARGINAL TO LOCALIZED CRITICAL CONDITIONS MAY DEVELOP AROUND PEAK
HEATING ON SUN. THE STRONGEST LOW-LEVEL SLYS SHOULD PRIMARILY BE
CONFINED E OF A DRYLINE MIXING ACROSS THE CNTRL/SRN PLAINS...WHERE
RH VALUES WILL BE INCREASINGLY MARGINAL WITH ERN EXTENT.
HOWEVER...AS LEE CYCLOGENESIS ENSUES INVOF NERN CO...A TIGHTENING
SURFACE PRESSURE GRADIENT W OF THE DRYLINE WILL OCCUR ACROSS THE
TX/OX PANHANDLES DURING MID TO LATE AFTERNOON. SUSTAINED SURFACE
WINDS SHOULD REACH 15 TO 20 MPH WITH RH VALUES OF 10 TO 20 PERCENT.
...NRN SACRAMENTO VALLEY IN NRN CA...
A HIGHLY LOCALIZED ENHANCED FIRE WEATHER THREAT SHOULD DEVELOP LATE
SUN AFTERNOON THROUGH THE EVENING. GUSTY NLY WINDS WILL DEVELOP AS
LOW-LEVEL PRESSURE GRADIENTS TIGHTEN SUBSTANTIALLY WITH A RIDGE
BUILDING INTO THE PACIFIC NW. SUSTAINED SURFACE WINDS SHOULD BECOME
MODERATE...REACHING 15 MPH. THIS WOULD BE INITIALLY JUXTAPOSED WITH
LOW RH VALUES OF 6 TO 12 PERCENT...AND POOR RH RECOVERY IS EXPECTED
THROUGH MUCH OF THE NIGHT.
..GRAMS.. 09/04/2010
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
Read more
