FEMA tornado/severe thunderstorm watches, mesoscale discussions, convective outlooks, fire weather outlooks

SPC Day 2 Fire Weather Outlook
DAY 2 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0350 AM CDT WED MAY 16 2012 VALID 171200Z - 181200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN GREAT BASIN... ...SYNOPSIS... A LARGE SCALE PATTERN SHIFT IS BEING FORECAST THROUGH THE END OF THE WORK WEEK AS A DEVELOPING PACIFIC TROUGH...CURRENTLY WELL OFF THE WEST COAST...MOVES OVER THE WRN STATES ON THURSDAY...AND A BROAD DOWNSTREAM RIDGE BUILDS OVER MUCH OF THE ERN U.S. WEAK TROUGHING WILL PERSIST FROM THE GULF OF MEXICO INLAND ACROSS THE SOUTHEAST AND FL. ...SRN NV ACROSS NRN AZ... MODEL GUIDANCE REMAINS CONSISTENT IN FORECASTING THE ADVANCE OF THE NEXT MID/UPPER LEVEL TROUGH AND ITS ASSOCIATED STRONGER WIND FIELDS CROSSING THE WEST COAST DURING THURSDAY. THIS SYSTEM APPEARS MORE PROGRESSIVE AND COVERS A LARGER AREA THAN THE MOST RECENT DISTURBANCE OF THE PAST COUPLE OF DAYS. TEMPERATURES IN THE CRITICAL RISK AREA WILL AGAIN CLIMB INTO THE LOW TO MID 90S F IN THE LOWER ELEVATIONS WITH 70S AND 80S F IN THE HIGHER ELEVATIONS. ENSEMBLE FORECASTS ACROSS THE REGION DEPICT VERY LIMITED OVERNIGHT RH RECOVERY AND THUS MINIMUM RH VALUES WILL FALL QUICKLY BELOW 10 PERCENT WITH HEATING OF THE DAY. SUSTAINED SWLY SURFACE WINDS OF 12-17 MPH WILL INCREASE TO 15-25 MPH THROUGH THE LATE AFTERNOON WITH GUSTS OF 35-40 MPH POSSIBLE BY EVENING. SURFACE WINDS MAY REMAIN RELATIVELY STRONG INTO THE EVENING AS STRONGER FLOW IN THE BASE OF THE MID/UPPER TROUGH IS FORECAST TO MOVE ACROSS SRN NV AND NRN AZ DURING THIS TIME. ANTICIPATED CONDITIONS AND ANTECEDENT SEVERE DROUGHT WILL EXACERBATE THE POTENTIAL FOR FIRE STARTS AND FIRE GROWTH THUS WARRANTING THE CRITICAL RISK AREA. ..CARBIN.. 05/16/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more

No watches are valid as of Wed May 16 08:52:02 UTC 2012.

No Mesoscale Discussions are in effect as of Wed May 16 08:52:02 UTC 2012.

Day 4-8 Outlook
DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0342 AM CDT WED MAY 16 2012 VALID 191200Z - 241200Z ...DISCUSSION... ISOLATED SEVERE POTENTIAL SHOULD EXIST ON SAT/D4 FROM THE UPPER MS VALLEY TO THE CNTRL PLAINS...WITH INCREASINGLY LIMITED PROSPECTS THEREAFTER. ABOVE-AVERAGE CONFIDENCE PERSISTS WITH HIGH CONTINUITY AMONG THE 00Z ECMWF/GFS AND GEFS MEAN WITH THE DEPICTION OF A DAMPENING SHORT WAVE TROUGH EJECTING FROM THE SRN ROCKIES INTO THE CNTRL PLAINS ON D4. AT THE SURFACE...A COLD FRONT WILL ADVANCE E/SEWD...LIKELY REACHING THE UPPER MS VALLEY TO CNTRL PLAINS BY SAT AFTERNOON. CONCERNS OVER WARM SECTOR MOISTURE RETURN DESCRIBED IN THE D2/3 OUTLOOKS SUGGEST GFS/GEFS MEAN SURFACE DEW POINTS CONTINUE TO DISPLAY A HIGH BIAS. GFSX MOS AND THE ECMWF APPEAR MORE REASONABLE WITH GENERALLY 50S SURFACE DEW POINTS. GIVEN THE DAMPENING NATURE OF THE SHORT WAVE TROUGH...MID-LEVEL FLOW NEARLY PARALLELING THE SURFACE FRONT AND LIKELY ONLY MODERATE BUOYANCY...SETUP DOES NOT RENDER SEVERE PROBABILITIES AOA 30 PERCENT ATTM. Read more

SPC Day 1 Fire Weather Outlook
DAY 1 FIRE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0254 AM CDT WED MAY 16 2012 VALID 161200Z - 171200Z ...SYNOPSIS... A DISTINCT SHORT WAVE PERTURBATION OVER NV IS FORECAST TO DEAMPLIFY WHILE TRACKING ACROSS THE INTERMOUNTAIN WEST THIS PERIOD. ANOTHER WELL DEFINED SRN STREAM VORTEX WILL MAKE SLOW EWD PROGRESS ALONG THE GULF COAST. BETWEEN THE NV AND GULF COAST TROUGHS A WEAK MID LEVEL RIDGE WILL TRANSLATE EAST ACROSS THE GREAT PLAINS. IN THE NRN STREAM...A PRONOUNCED AND PROGRESSIVE SHORT WAVE TROUGH WILL MOVE FROM THE GREAT LAKES TO THE NORTHEAST/NRN NEW ENGLAND THROUGH TONIGHT. THE COLD FRONT ACCOMPANYING THIS SYSTEM WILL SURGE EWD/SEWD THIS PERIOD AND EXTEND FROM THE CANADIAN MARITIME PROVINCES TO THE MID ATLANTIC BY EARLY THURSDAY. ...NORTHEAST AZ ACROSS FOUR CORNERS... A BELT OF STRONGER FLOW IN THE BASE OF THE EJECTING MID/UPPER TROUGH WILL SPREAD EAST ACROSS NERN AZ AND SRN UT AND THEN TOWARD THE FOUR CORNERS AREA THROUGH THE LATE AFTERNOON. AS TEMPERATURES CLIMB INTO THE LOW TO MID 80S F FROM NERN AZ TO THE FOUR CORNERS...RH VALUES SHOULD FALL INTO THE TEENS OR LOWER. THE PROGRESSIVE NATURE OF THE MID/UPPER WAVE AND TURBULENT MIXING THROUGHOUT THE DEEPENING BOUNDARY LAYER WILL CONTRIBUTE TO A 1 TO 2 HOUR PERIOD OF STRONGER SURFACE WINDS COINCIDENT WITH MAX HEATING. EXPECT SUSTAINED SSWLY WINDS OF 12-17 /GUSTS 25-30/ MPH IN LOWER ELEVATIONS WITH HIGHER SUSTAINED WINDS TO 25 /GUSTS TO 40/ MPH ACROSS HIGHER ELEVATIONS. WINDS WILL SHIFT TO WSWLY AND WLY AND THEN WEAKEN WITH THE PASSAGE OF THE TROUGH LATE IN THE DAY FROM WEST TO EAST. ANTECEDENT SEVERE TO EXTREME DROUGHT WILL CONTRIBUTE TO THE FIRE THREAT IN THE REGION TODAY BUT OVERALL CONDITIONS ARE NOT EXPECTED TO EXCEED THE THRESHOLD FOR A CRITICAL RISK AREA. ...CENTRAL HIGH PLAINS... DESPITE A GRADUAL DEAMPLIFICATION OF THE SHORT WAVE CROSSING THE FOUR CORNERS AREA...MODEST DOWNSTREAM SURFACE CYCLOGENESIS IS FORECAST IN THE LEE OF THE ROCKIES. SUBSEQUENT MASS ADJUSTMENT WILL SUPPORT AN INCREASE IN SUSTAINED SLY WINDS TO ABOUT 25-35 MPH ACROSS THE HIGH PLAINS FROM ERN CO ACROSS THE NEB PNHDL THIS AFTERNOON. TEMPERATURES WILL CLIMB INTO THE LOWER 80S F IN THESE AREAS WHILE RH FALLS TO ABOUT 15-20 PERCENT. IN ADDITION TO POCKETS OF ABNORMAL DRYNESS AND MODERATE DROUGHT OVER SOME OF THE REGION...A FEW LATE DAY HIGH-BASED/DRY TSTMS MAY SPREAD EAST FROM THE HIGHER TERRAIN AND POSE SOME THREAT OF ERRATIC GUSTY WINDS AND POSSIBLE ISOLATED LIGHTNING STARTS. OVERALL RISK APPEARS LIMITED BY MARGINAL RH VALUES. ..CARBIN.. 05/16/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT... Read more

SPC 0730Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT WED MAY 16 2012 VALID 181200Z - 191200Z ...SYNOPSIS... MODEL GUIDANCE IS HIGHLY CONSISTENT THAT A SHORT WAVE IMPULSE EMBEDDED WITHIN AN AMPLIFIED UPPER-LEVEL TROUGH SHOULD TRACK FROM THE SOUTHWEST TO THE SRN ROCKIES ON D3. A LEE SURFACE TROUGH WILL PERSIST FROM THE BLACK HILLS TO THE SRN HIGH PLAINS...INTERSECTING A COLD FRONT THAT SHOULD ACCELERATE SEWD ACROSS THE NRN INTO THE CNTRL HIGH PLAINS BY EARLY SAT. ...NRN TO SRN HIGH PLAINS... ALTHOUGH THIS WILL BE THE THIRD DAY OF POLEWARD TRANSPORT OF A MARGINALLY MOIST AIR MASS FROM THE SRN PLAINS...RETURN FLOW OFF THE WRN GULF SHOULD REMAIN MODEST AFTER NOT COMMENCING UNTIL LATE D2. SURFACE DEW POINTS /ALTHOUGH INCREASING/ WILL BE MARGINAL FOR A TYPICAL PLAINS WARM SECTOR...LARGELY EXPECTED TO BE IN THE 30S/40S ALONG THE LEE TROUGH IN THE HIGH PLAINS TO PERHAPS LOWER 50S OVER THE NRN PLAINS ALONG THE COLD FRONT. STRENGTHENING CONVERGENCE ALONG THESE BOUNDARIES AND STRONG HEATING SHOULD GENERALLY RESULT IN WEAK BUOYANCY AND AT LEAST ISOLATED TSTMS FORMING DURING THE LATE AFTERNOON TO EARLY EVENING. DEEP-LAYER FLOW WILL GRADUALLY INCREASE WITH APPROACH OF THE WRN CONUS TROUGH...BUT SHOULD REMAIN LARGELY MODERATE AND LIKELY STRONGER WITH NRN EXTENT. THIS MAY SUPPORT A FEW HIGH-BASED SUPERCELL STRUCTURES CAPABLE OF ISOLATED SEVERE WIND/HAIL. STILL...WITH MID-LEVEL S/SWLYS ROUGHLY PARALLELING THE SURFACE COLD FRONT AND ANAFRONTAL CHARACTERISTICS OF THIS BOUNDARY...PROSPECTS FOR SUSTAINED ORGANIZED STORMS APPEAR TOO MARGINAL TO WARRANT A SLIGHT RISK DELINEATION ATTM. ..GRAMS.. 05/16/2012 Read more

SPC 0600Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1244 AM CDT WED MAY 16 2012 VALID 171200Z - 181200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... A WEAK UPPER-LEVEL TROUGH CENTERED OVER THE WRN GULF COAST WILL APPROACH THE ERN GULF COAST REGION BY THU. A SHORT WAVE TROUGH OVER THE SRN GREAT BASIN WILL DAMPEN AS IT REACHES THE SRN ROCKIES THU MORNING AND DRIFTS EWD INTO THE CNTRL/SRN HIGH PLAINS. THIS FEATURE WILL BECOME EMBEDDED WITHIN A BUILDING UPPER-LEVEL RIDGE OCCURRING DOWNSTREAM OF AN AMPLIFIED TROUGH ENTERING THE WEST. LEE SURFACE TROUGH SHOULD PERSIST ACROSS THE BULK OF THE HIGH PLAINS...WITH A LLJ NOCTURNALLY STRENGTHENING FROM THE SRN HIGH PLAINS TO THE UPPER MS VALLEY. ...CNTRL/SRN FL... A SWATH OF 25-40 KT WLYS AT 500 MB SHOULD BE PREVALENT OVER MOST OF THE PENINSULA AHEAD OF AN APPROACHING WEAK TROUGH. MID-LEVEL LAPSE RATES WILL REMAIN POOR...BUT POCKETS OF STRONGER INSOLATION/HEATING COUPLED WITH MIDDLE TO UPPER 60S SURFACE DEW POINTS SHOULD RESULT IN MODEST BUOYANCY AND AID IN THE DEVELOPMENT OF SCATTERED TSTMS DURING THE AFTERNOON. A FEW MULTICELL CLUSTERS SHOULD FORM AND MAY YIELD LOCALLY DAMAGING WINDS/MARGINALLY SEVERE HAIL. ...HIGH PLAINS TO UPPER MS VALLEY... THE DEVELOPMENT OF A NOCTURNAL LLJ ON D1 WILL LEAD TO POLEWARD TRANSPORT OF A MARGINALLY MOIST AIR MASS FROM THE SRN PLAINS...WITH WEAK RETURN FLOW NOT COMMENCING UNTIL LATE D2 ALONG THE WRN GULF COAST. AS SUCH...SURFACE DEW POINTS /ALTHOUGH INCREASING/ SHOULD BE RATHER LOW FOR A TYPICAL PLAINS WARM SECTOR...WHICH APPEARS BEST HANDLED BY THE 00Z NAM COMPARED TO OTHER GUIDANCE. ISOLATED TO WIDELY SCATTERED HIGH-BASED TSTMS MAY FORM ALONG THE LEE TROUGH AT PEAK HEATING. BUT WEAK DEEP-LAYER SHEAR SHOULD RESULT IN A PULSE-TYPE MODE AND THE THREAT FOR DRY MICROBURSTS APPEARS TOO MARGINAL TO WARRANT SEVERE PROBABILITIES ATTM. A SEPARATE AREA OF ELEVATED CONVECTION SHOULD NOCTURNALLY FORM WITH A LOW-LEVEL WAA REGIME IN THE UPPER MS VALLEY. NAM FORECAST SOUNDINGS SUGGEST PARCELS WOULD HAVE ONLY MODEST SHEAR IN THE CLOUD-BEARING LAYER...WHICH SHOULD MITIGATE SEVERE HAIL POTENTIAL. ..GRAMS.. 05/16/2012 Read more

SPC 1200Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1234 AM CDT WED MAY 16 2012 VALID 161200Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN NY AND WRN NEW ENGLAND... ...NERN STATES... AN UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE ERN GREAT LAKES TODAY. AS THE TROUGH APPROACHES NEW ENGLAND...THUNDERSTORMS WILL LIKELY DEVELOP THIS AFTERNOON AHEAD OF A BAND OF STRONG LARGE-SCALE ASCENT MOVING INTO NY. AHEAD OF THE CONVECTION...AN AXIS OF MODERATE INSTABILITY IS FORECAST FROM NEW JERSEY NNEWD INTO VERMONT WHERE FORECAST SOUNDINGS SHOW MLCAPE VALUES REACHING THE 1000 TO 1500 J/KG RANGE. THIS ALONG WITH 0-6 KM SHEAR OF 40 TO 50 KT SHOULD SUPPORT SUPERCELL DEVELOPMENT WHERE THE CELLS REMAIN DISCRETE. HOWEVER...THE MODELS APPEAR TO BE DEVELOPING A LINE OF THUNDERSTORMS ALONG A FAST MOVING COLD FRONT MOVING WEST TO EAST ACROSS THE SLIGHT RISK AREA LATE THIS AFTERNOON. IF SUPERCELLS DEVELOP AHEAD OF THE LINE...THEN A LARGE HAIL THREAT SHOULD EXIST. THE GREATER THREAT COULD BE FOR DAMAGING WIND GUSTS WITH A LINEAR CONVECTIVE SYSTEM. A SEVERE THREAT MAY EXTEND SWWD INTO ERN PA AND NJ ALONG THE AXIS OF MODERATE INSTABILITY BUT STORM COVERAGE SHOULD BE VERY ISOLATED FURTHER TO THE SOUTH. ...ERN CAROLINAS/SE GA/NE FL... SOUTHWEST FLOW WILL REMAIN IN PLACE ACROSS THE ERN GULF COAST STATES AND CAROLINAS TODAY. MODEL FORECASTS DEVELOP MODERATE INSTABILITY FROM NRN FL NEWD INTO THE ERN CAROLINAS WHERE THUNDERSTORM DEVELOPMENT SHOULD OCCUR THIS AFTERNOON. THE GREATEST CONVECTIVE COVERAGE SHOULD EXIST ALONG SEA BREEZE BOUNDARIES WHERE ISOLATED DAMAGING WIND GUSTS MAY OCCUR DUE TO STEEP LOW-LEVEL LAPSE RATES. THE SEVERE THREAT SHOULD BE CONCENTRATED IN THE LATE AFTERNOON NEAR THE PEAK IN DESTABILIZATION. ..BROYLES/COHEN.. 05/16/2012 Read more