Storm Prediction Center Day 1 Fire Weather Outlook
Created: Fri Jun 14 16:19:03 UTC 2013
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ZCZC SPCFWDDY1 ALL FNUS21 KWNS 141618 DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 AM CDT FRI JUN 14 2013 VALID 141700Z - 151200Z ...CRITICAL FIRE WEATHER AREA FOR W-CNTRL/SWRN KS AND A SMALL PART OF SERN CO... ...W-CNTRL/SWRN KS AND A SMALL PART OF SERN CO... NO CHANGES REQUIRED. CRITICAL CONDITIONS MAY BE LOW-END/BORDERLINE BUT GIVEN DRY FUELS AND ONGOING DROUGHT A CRITICAL SEEMS WARRANTED. WIND SPEEDS WERE ALREADY NEAR 20 MPH WITH HIGHER GUSTS ACROSS THE CRITICAL AREA THIS MORNING. RH VALUES WILL CONTINUE TO FALL AS TEMPERATURES WARM INTO THE 90S BY EARLY AFTERNOON. THUNDERSTORMS ARE ALSO POSSIBLE ACROSS THE AREA LATER THIS AFTERNOON. WHILE WETTING RAINS ARE EXPECTED WITH THESE STORMS...ANY LIGHTNING STRIKES OUTSIDE THE MAIN RAIN CORE COULD POSE A THREAT FOR LIGHTNING IGNITIONS. ...SURROUNDING THE CRITICAL AREA ACROSS PORTIONS OF NERN NM...THE TX/OK PANHANDLE...WRN KS...SERN CO... NO CHANGES REQUIRED. ...NRN AZ...SRN NV...SRN UT... NO CHANGES REQUIRED. ...PORTIONS OF WRN NM...SERN AZ...S-CNTRL CO -- FOR DRY THUNDERSTORM POTENTIAL... NO CHANGES REQUIRED. ...SACRAMENTO VALLEY IN CA... NO CHANGES REQUIRED. ..LEITMAN.. 06/14/2013 .PREV DISCUSSION... /ISSUED 0325 AM CDT FRI JUN 14 2013/ ...SYNOPSIS... A MID-LEVEL SHORTWAVE TROUGH IS FORECAST TO TRACK EWD FROM THE NRN ROCKIES TO THE NRN PLAINS THROUGH THE PERIOD. A ZONE OF MODESTLY ENHANCED MID-LEVEL FLOW WILL TRAIL SWWD/WSWWD FROM A STRONGER MID-LEVEL JET CORE ACCOMPANYING THE SHORTWAVE TROUGH...INTO PARTS OF THE CNTRL GREAT BASIN AND SW STATES. A DOWNSTREAM RIDGE ALIGNED N-S OVER THE PLAINS WILL ADVANCE EWD TOWARD THE MS VALLEY WHILE EXPERIENCING SLIGHT DEAMPLIFICATION OVER ITS NRN EXTENT. MEANWHILE...A MID-LEVEL DISTURBANCE IS FORECAST TO SLOWLY MOVE NWD ACROSS PARTS OF WRN TX OVER THE SWRN FLANK OF THE AFOREMENTIONED RIDGE. AT THE SFC...A FRONT WILL EXTEND FROM THE CNTRL GREAT BASIN INTO THE CNTRL PLAINS AND THEN SEWD INTO PARTS OF THE SERN STATES. ...PORTIONS OF W-CNTRL/SWRN KS...A SMALL PART OF SERN CO... THE AREA HAS BEEN UPGRADED TO CRITICAL DESIGNATION UPON COORDINATION WITH THE DODGE CITY KS...GOODLAND KS...AND PUEBLO CO WEATHER FORECAST OFFICES. A LOW-LEVEL THERMAL RIDGE WILL EXTEND FROM THE HIGH PLAINS OF SERN CO NEWD INTO PARTS OF WRN KS OVER THE WRN FLANK OF THE MID-LEVEL RIDGE COVERING THE PLAINS. TO THE S OF THE AFOREMENTIONED FRONT...AND TO THE E OF A LEE SFC TROUGH...THE BOUNDARY LAYER WILL SUBSTANTIALLY DEEPEN THROUGH THE DAY IN THE VICINITY OF THE THERMAL RIDGE. SFC TEMPERATURES ARE FORECAST TO CLIMB INTO THE UPPER 90S TO AROUND 100 DEGREES...WITH RH VALUES FORECAST TO FALL TO AROUND 15 PERCENT THIS AFTERNOON. THE TIGHT SFC PRESSURE GRADIENT S OF THE FRONT/E OF THE LEE TROUGH IS EXPECTED TO SUPPORT SLY/SSWLY SFC WINDS OF 20-25 MPH WITH GUSTS REACHING AROUND 30 MPH. OF NOTE...RH VALUES MAY ONLY BECOME MARGINALLY CRITICAL IN SOME CIRCUMSTANCES. HOWEVER...THE ANTICIPATED RH VALUES...WHEN COMBINED WITH /1/ THE STRONG WINDS.../2/ THE HOT AIR MASS.../3/ THE EXCEPTIONAL DROUGHT CONDITIONS IN MANY AREAS...AND /4/ THE LIMITED MAGNITUDE OF RECENT PRECIPITATION...STILL SUPPORT CRITICAL DESIGNATION. ALSO...THUNDERSTORM DEVELOPMENT IS ANTICIPATED DURING THE AFTERNOON IN THE VICINITY OF THE FRONT AND LEE TROUGH FROM PARTS OF NWRN KS INTO ERN CO...AND THIS ACTIVITY MAY DEVELOP INTO PORTIONS OF THE CRITICAL AREA THROUGH THE EVENING HOURS. PRECIPITATION CORES ARE EXPECTED TO PRODUCE WETTING RAINS GIVEN PW VALUES IN EXCESS OF 0.85 INCH AND ONLY MODEST STORM MOTIONS. HOWEVER...OVER THE PERIPHERIES OF THESE PRECIPITATION CORES...LIGHTNING-INDUCED IGNITIONS MAY OCCUR...WITH FIRE SPREAD POTENTIALLY BEING ENHANCED BY GUSTY/ERRATIC OUTFLOW WINDS. ...SURROUNDING THE CRITICAL AREA ACROSS PORTIONS OF NERN NM...THE TX/OK PANHANDLES...WRN KS...SERN CO... ELEVATED FIRE WEATHER CONDITIONS WILL BE OF CONCERN...AS SLY/SSWLY SFC WINDS OF 15-25 MPH AND HIGHER GUSTS IMPACT THE AREA AND RH VALUES FALL TO AROUND 20-25 PERCENT. HOWEVER...THE ABSENCE OF HIGHER LOW-LEVEL TEMPERATURES AND/OR THE PRESENCE OF HIGHER BOUNDARY-LAYER DEWPOINTS ARE CURRENTLY EXPECTED TO PREVENT CRITICALLY LOW RH VALUES FROM OCCURRING ON ANY MORE THAN A BRIEF/SPOTTY BASIS IN CONJUNCTION WITH STRONG WINDS. ALSO...WIND SPEEDS N OF THE FRONT ARE EXPECTED TO BE LIGHTER ACROSS PARTS OF NWRN KS WHERE RELATIVELY WEAKER LOW-LEVEL FLOW AND MORE SHALLOW SFC-BASED MIXED LAYERS ARE ANTICIPATED. RECENT PRECIPITATION MAY ALSO MITIGATE THE FIRE WEATHER POTENTIAL IN PARTS OF NWRN KS N OF THE FRONT. ...NRN AZ...SRN NV...SRN UT... THE ZONE OF MODESTLY ENHANCED...TRAILING MID-LEVEL FLOW IS EXPECTED TO OVERLIE A DRY ANTECEDENT BOUNDARY LAYER TO SUPPORT ELEVATED FIRE WEATHER CONDITIONS. THIS WILL OCCUR AS SLY TO WLY SFC WINDS OF 15 TO AROUND 20 MPH COMBINE WITH MINIMUM RH VALUES FROM THE MIDDLE SINGLE DIGITS TO AROUND 15 PERCENT AMIDST DRY FUELS. HOWEVER...IN THE ABSENCE OF STRONGER LOW/MID-LEVEL FLOW...CRITICALLY STRONG SUSTAINED WIND SPEEDS ARE NOT EXPECTED TO OCCUR ON ANY MORE THAN A BRIEF/SPOTTY BASIS. THUS...NO UPGRADE TO CRITICAL DESIGNATION HAS BEEN MADE AT THIS TIME. ...PORTIONS OF WRN NM...SERN AZ...S-CNTRL CO -- DRY THUNDERSTORM POTENTIAL... EARLY-MORNING WATER VAPOR IMAGERY INDICATES A PLUME OF ENHANCED MID-LEVEL MOISTURE EXTENDING SW-NE FROM PARTS OF THE SWRN STATES TO THE NRN PLAINS BETWEEN THE AFOREMENTIONED SHORTWAVE TROUGH AND THE PLAINS RIDGE. THE SRN EXTENT OF THIS MOIST PLUME IS EXPECTED TO GRADUALLY MOVE EWD TODAY...AND OVERLIE THE REGION DURING PEAK HEATING. FOR THIS AFTERNOON...OROGRAPHIC CIRCULATIONS AMIDST THE MOIST PLUME AND MODEST BUOYANCY WILL SUPPORT THE DEVELOPMENT OF ISOLATED TO SCATTERED THUNDERSTORMS. PW VALUES ARE FORECAST TO RANGE FROM AROUND 0.5 TO 0.9 INCH ACROSS THE AREA AND SUPPORT DRY THUNDERSTORM AND MIXED WET/DRY THUNDERSTORM MODES. HOWEVER...IN THE ABSENCE OF STRONGER DEEP-LAYER FORCING FOR ASCENT...ANY THUNDERSTORM COVERAGE IS EXPECTED TO REMAIN ISOLATED IN AREAS WHERE PW VALUES ARE AT THE LOWER END OF THE AFOREMENTIONED RANGE FAVORING A DRY THUNDERSTORM MODE -- I.E. ACROSS PARTS OF NWRN/N-CNTRL NM INTO S-CNTRL CO. GREATER THUNDERSTORM COVERAGE WILL BE RELEGATED TO AREAS OF HIGHER PW FROM SERN AZ INTO CNTRL/S-CNTRL/SWRN NM...THOUGH THESE STORMS WOULD LIKELY EXHIBIT A MIXED WET/DRY MODE. REGARDLESS...LIGHTNING-INDUCED IGNITIONS WILL BE OF CONCERN ACROSS THE REGION AS FUELS ARE DRY. HOWEVER...WITHOUT HIGHER CONFIDENCE IN ANY MORE THAN ISOLATED COVERAGE OF PURELY DRY THUNDERSTORMS OCCURRING...A CRITICAL AREA FOR DRY THUNDERSTORMS HAS NOT BEEN INTRODUCED AT THIS TIME. ...SACRAMENTO VALLEY IN CA... A MODESTLY ENHANCED SFC PRESSURE GRADIENT MAY SUPPORT NLY SFC WINDS FROM 15 TO AROUND 20 MPH DURING THE MORNING HOURS. HOWEVER...WINDS ARE EXPECTED TO WEAKEN DURING THE AFTERNOON AS RH VALUES FALL TO MINIMUM VALUES AROUND 9-14 PERCENT...LIKELY PREVENTING THE OVERLAP OF CRITICALLY STRONG WINDS AND CRITICALLY LOW RH. WHILE A BRIEF PERIOD OF MODESTLY ELEVATED FIRE WEATHER CONDITIONS MAY OCCUR DURING THE LATE MORNING/EARLY AFTERNOON AIDED BY DRY FUELS...CRITICAL FIRE WEATHER CONDITIONS ARE UNLIKELY. AS SUCH...NO FIRE WEATHER HIGHLIGHTS HAVE BEEN INCLUDED AT THIS TIME. ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...