What We Do

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1208 AM CDT SAT SEP 04 2010

VALID 041200Z - 051200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
PROGRESSIVE NRN-STREAM PATTERN FCST TO CONTINUE...LED BY MID-UPPER
LEVEL CYCLONE NOW CENTERED OVER NRN ONT THAT IS FCST TO
SHIFT/REDEVELOP NNEWD ACROSS ERN HUDSON BAY AND NWRN QUE.  UPSTREAM
RIDGING WILL MOVE EWD ACROSS CANADIAN PRAIRIE PROVINCES AND NRN HIGH
PLAINS OF CONUS.  MEANWHILE...STG SHORTWAVE TROUGH -- NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY MOVING ASHORE BC -- IS FCST TO EVOLVE INTO
CLOSED LOW OVER NRN BC AND THEN NRN AB.  SPEED MAX DIGGING SEWD W OF
THIS FEATURE WILL LEAD TO OVERALL AMPLIFICATION OF TROUGH S OF
LOW...WITH STG HEIGHT FALLS ACROSS PAC NW AND NRN ROCKIES THROUGH
MUCH OF PERIOD.  BY 5/12Z...TROUGH POSITION SHOULD EXTEND FROM
CANADIAN ROCKIES SSWWD ACROSS ERN WA...CENTRAL ORE AND NRN CA.

AT SFC...LEE CYCLOGENESIS WILL OCCUR AHEAD OF UPPER LOW OVER
AB...WITH TROUGHING SEWD ACROSS MT.  THIS LOW SHOULD MOVE EWD TOWARD
SK...WHILE FRONTOGENESIS OCCURS TO ITS SW OVER NRN ROCKIES.  BY END
OF PERIOD...FRONT SHOULD BE MOVING EWD/SEWD ACROSS NERN MT...SWRN MT
AND WRN ID.  WEAKER/SECONDARY LOW MAY FORM ALONG LEE TROUGH OVER
CENTRAL/SRN MT AROUND 5/00Z...AND MOVE ESEWD TO SEWD TO WRN SD.

...NRN HIGH PLAINS REGION...
WIDELY SCATTERED TSTMS SHOULD INITIATE THIS AFTERNOON ON HIGHER
TERRAIN OF MOUNTAINS/FOOTHILLS...AND POSSIBLY IN CONVERGENT AREAS
NEAR FRONT AND LEE TROUGH AS WELL.  MOST INTENSE TSTMS MAY PRODUCE
ISOLATED SVR/DAMAGING GUSTS.  AS TROUGHING AND RELATED HEIGHT FALLS
APCH...STRONG MID-UPPER WINDS AND NEARLY UNIDIRECTIONAL DEEP-LAYER
WIND FIELDS ARE EXPECTED...WITH AT LEAST MRGL BUOYANCY DEVELOPING
DIURNALLY ATOP DEEP/WELL-MIXED BOUNDARY LAYER.  LARGE-SCALE ASCENT
-- RELATED TO VARIOUS EXTENTS TO MIDLEVEL DPVA...AGEOSTROPHICALLY
FORCED ASCENT IN LEFT-EXIT REGION OF UPPER JET MAX...AND LOW-LEVEL
WAA...WILL CONTRIBUTE TO DESTABILIZATION ALOFT.  DESPITE RELATIVELY
MEAGER MOISTURE -- I.E. SFC DEW POINTS MAINLY 30S AND 40S F --
DEEP-LAYER LAPSE RATES SHOULD BE STEEP ENOUGH DURING MID-LATE
AFTERNOON TO SUPPORT MLCAPE IN 250-500 J/KG RANGE.  GUST POTENTIAL
WITH THIS ACTIVITY SHOULD DIMINISH AFTER DARK ACROSS ERN MT AS IT
MOVES INTO PROGRESSIVELY MORE STABLE BOUNDARY-LAYER AIR MASS...BOTH
WITH TIME AND WITH EWD EXTENT.

..EDWARDS/STOPPKOTTE.. 09/04/2010

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...