Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/08/13


AREA FORECAST DISCUSSION
NWS TUCSON AZ
915 PM MST SUN MAY 5 2013 .SYNOPSIS...SHOWERS WILL SPREAD INTO THE AREA LATER TONIGHT INTO EARLY MONDAY MORNING. PERIODS OF CLOUDS THROUGHOUT MUCH OF THE WEEK AS LOW PRESSURE SETTLES IN OVER SOUTHERN ARIZONA. TEMPERATURES RUNNING ABOUT SIX TO TEN DEGREES COOLER THAN AVERAGE. A FEW SHOWERS POSSIBLE LATER IN THE WEEK AS WELL. && .DISCUSSION...LIGHT SHOWERS SPREADING IN FROM THE SOUTHWEST WITH EMBEDDED MODERATE SHOWER ACTIVITY AND EVEN A COUPLE OF LIGHTNING STRIKES STILL WELL SOUTHWEST OF THE BORDER. TIA DEWPOINT HOPPED INTO THE UPPER 30S IN THE PAST 30 MINUTES WITH 30S COMMON NOW THROUGH SE AZ. SATELLITE SOUNDER PRECIPITABLE WATER ESTIMATES HAVE US AROUND THE .5 TO .6 RANGE WITH .75 TO .85 VALUES JUST SOUTHWEST OF US. STILL EXPECTING THE BEST DYNAMICS AND MOISTURE COUPLET (SUCH AS IT IS) BETWEEN 06Z AND 09Z. LARGE SCALE BLOCKING FEATURES IMMEDIATELY UPSTREAM AND DOWNSTREAM WILL KEEP A WEAK MEAN TROUGH POSITION THROUGH THE AREA THIS WEEK. A FEW LIGHT SHOWERS WITH PERIODS OF CLOUDINESS. TEMPERATURES TO RUN UP TO 10 DEGREES BELOW CLIMO MOST OF THE WEEK. GRADIENT ENHANCEMENT TO WINDS THROUGH WEDNESDAY OR SO. A STRONGER BIT OF REINFORCING ENERGY COULD BRING MORE ORGANIZED SHOWERS TO THE AREA AROUND THURSDAY NIGHT OR FRIDAY. && .PREV DISCUSSION...00Z KTWC SOUNDING CREPT BACK JUST ABOVE 1/2 INCH PRECIPITABLE WATER FOR THE FIRST TIME IN A FEW WEEKS. HIGHER VALUES LINING UP TO PUSH THIS WAY TONIGHT FROM THE SOUTH AND SOUTHWEST ON BLENDED TOTAL PRECIPITABLE WATER IMAGERY. LATEST NAMDNG5 AND RAPID REFRESH TRENDS CONTINUE TO ROTATE THE IMPULSE CURRENTLY NEAR THE NORTHERN BAJA PENINSULA QUICKLY UNDER AND UP AHEAD OF THE CONSOLIDATING LOW POSITION...THEN THROUGH SOUTHEAST ARIZONA AFTER 06Z. WE EARLIER ADJUSTED POP AND QPF TRENDS UP...WHILE NARROWING THE WINDOW FOR THE MAIN FOCUS OF PRECIP CHANCES PRIMARILY BETWEEN 06Z-12Z FOR MOST OF SE AZ. HRRR CAPE IS ELEVATED TO A COUPLE OF POCKETS ABOVE 500J AS THIS FEATURE PUSHES THROUGH SO A LIGHTNING STRIKE OR TWO IS NOT OUT OF THE QUESTION. && .AVIATION...MID CLOUDS THICKENING AND LOWERING FROM WEST TO EAST...WITH SCT-BKN CLOUDS AT 7-10K FT AGL BETWEEN 06/04Z AND 06/16Z. CHC -SHRA/-TSRA BETWEEN 06/06Z AND 06/15Z. SLY/SWLY SURFACE WIND AT 10-15 KTS WITH GUSTS TO 25 KTS TIL 06/06Z. AFT 06/06Z...SURFACE WIND DIMINISHING...AND MAINLY LESS THAN 10 KTS BY 06/12Z. SWLY SURFACE WIND INCREASING AGAIN AFT 06/17Z TO 12-17 KTS AND HIGHER GUSTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...COOLER TEMPERATURES ARE EXPECTED THROUGH THE END OF THE UPCOMING WORK WEEK. THERE WILL BE A CHANCE OF SHOWERS TONIGHT INTO MONDAY...ALONG WITH A POSSIBLE LIGHTNING STRIKE OR TWO. BREEZY WINDS ARE ALSO EXPECTED THROUGH AT LEAST TUESDAY. WITH THE COOLER TEMPERATURES AND CORRESPONDING INCREASES IN RELATIVE HUMIDITY VALUES...CONDITIONS ARE EXPECTED TO REMAIN BELOW CRITICAL FIRE WEATHER THRESHOLDS...EVEN THOUGH WINDS WILL BE STRONG AT TIMES DURING THE AFTERNOON AND EARLY EVENING HOURS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON MEYER/LADER AVIATION/FIRE WEATHER...ZELL
AREA FORECAST DISCUSSION
NWS PUEBLO CO
926 PM MDT TUE MAY 7 2013 .UPDATE... ISSUED AT 925 PM MDT TUE MAY 7 2013 UPDATED FOR CURRENT OBSERVATIONS AND RADAR TRENDS. HAVE KEPT CURRENT WINTER STORM WATCH FOR THE HIGH MT PEAKS...AOA 10K FEET AS QUICK PEAK AT 00Z NAM NOT AS BULLISH WITH QPF ACROSS THE REGION. STILL LOOKS LIKE BEST SNOW ACCUMS WILL BE ACROSS THE CENTRAL MTS AND POSSIBLY PIKES PEAK WITH ADVISORY AMOUNTS LIKELY...THOUGH WILL LET MID SHIFT GET A LOOK AT LATEST GLOBAL MODELS BEFORE ISSUING ANY HIGHLIGHTS. LATEST NAM PICKING UP ON THE HRRR AND RAP TRENDS OF SHOWERS DEVELOPING ACROSS THE SOUTHERN MTS AFTER MIDNIGHT AND SPREADING NORTH AND EAST THROUGH THE EARLY MORNING HOURS AS JETLET MOVES ACROSS THE SOUTHERN ROCKIES AND MID LEVEL DEFORMATION INCREASES ACROSS THE AREA. LATEST NAM QPF TREND ALSO BODES WELL FOR THE WALDO CANYON BURN SCAR...AND WILL WAIT AND SEE IF THE GLOBAL MODELS FOLLOW SUIT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 243 PM MDT TUE MAY 7 2013 ACTIVE METEOROLOGICAL REGIME DURING THE SHORT TERM(ESPECIALLY WEDNESDAY) WITH ONE CONCERN BEING HEAVY RAIN POTENTIAL(SHOWERS AND THUNDERSTORMS)...ESPECIALLY OVER THE WALDO CANYON BURN SCAR BUT ALSO OVER MANY OTHER LOCATIONS OF THE FORECAST DISTRICT AS VIGOROUS CLOSED UPPER LOW SHIFTS FROM FAR NORTHWESTERN ARIZONA AT 00Z WEDNESDAY INTO SOUTHWESTERN COLORADO BY 00Z THURSDAY. I WILL BE ISSUING A FLOOD WATCH FOR THE FLASH FLOODING POTENTIAL(FOCUSED ON THE WALDO CANYON BURN SCAR AREA) FOR PUBLIC ZONES 81/84 AND 85 FROM 12Z WEDNESDAY THROUGH 00Z FRIDAY. ANOTHER CONCERN WILL BE THE STRONG TO SEVERE THUNDERSTORM POTENTIAL OVER PORTIONS OF THE SOUTHEASTERN COLORADO PLAINS FROM WEDNESDAY INTO WEDNESDAY NIGHT THANKS TO DEEPENING ATMOSPHERIC MOISTURE LEVELS...UPPER ENERGY MOVING ACROSS THE CWFA...0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS...LOCALIZED CAPES AROUND 1800 J/KG AND LOCALIZED LIS AROUND -6C. SPC 2ND DAY CONVECTIVE OUTLOOK HAS PORTIONS OF KIOWA...BENT...PROWERS AND BACA COUNTY IN THEIR SEVERE THUNDERSTORM OUTLOOK FOR WEDNESDAY. I WILL HAVE SEVERE THUNDERSTORM WORDING IN MY IMPENDING ZONES/GRIDS FOR THE ABOVE MENTIONED COUNTIES FOR WEDNESDAY AFTERNOON. AN ADDITIONAL METEOROLOGICAL ISSUE WILL BE THE POTENTIAL FOR HIGHER TERRAIN ACCUMULATING SNOW...ESPECIALLY FROM WEDNESDAY INTO THURSDAY. I WILL BE ISSUING A WINTER STORM WATCH FOR PUBLIC ZONES 58/60/73/75/80 AND 82 FROM 13Z WEDNESDAY TO 03Z FRIDAY TO ACCOUNT FOR THIS POTENTIAL. IN ADDITION..FOR TONIGHT I HAVE DEPICTED GENERALLY UNDER 4 INCHES OF SNOW OVER PORTIONS OF ZONES 58 AND 60 WILL LOWER SNOW AMOUNTS OVER OTHER HIGHER TERRAIN LOCATIONS. MINIMUM TEMPERATURES TONIGHT ARE EXPECTED TO RUN A CATEGORY OR SO ABOVE EARLY MAY CLIMATOLOGICAL AVERAGES MOST AREAS WHILE MAXIMUM TEMPERATURES ON WEDNESDAY SHOULD RUN A CATEGORY OR TWO BELOW EARLY MAY CLIMATOLOGICAL AVERAGES. FINALLY...LOW-GRADE GRADIENT WINDS ARE ANTICIPATED THROUGH 00Z THURSDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 243 PM MDT TUE MAY 7 2013 ...MORE HEAVY RAIN IN THE FORECAST... ...HEAVY WET SNOW FOR THE HIGHER ELEVATIONS... EXTENDED PERIOD CONTINUES TO LOOK FAIRLY WET...PARTICULARLY WED EVE THROUGH THU EVE...AND THEN ANOTHER ROUND LATE FRI INTO THE WEEKEND. MAIN CONCERN CONTINUES TO BE THE WALDO BURN SCAR DURING THIS TIME. WED EVE INTO THU...UPPER LOW OVER S CENTRAL CO WILL RETROGRADE WWD TO AZ BY THU EVE. HIGH PWATS CIRCULATING AROUND THE LOW WILL KEEP THE THREAT OF HEAVY SHOWER ACTIVITY GOING OVER MUCH OF OUR CWA. THE HIGHEST QPF STILL LOOKS TO BE OVER THE CONTDVD N OF KMYP...AND THE PIKES PEAK REGION. TOTAL QPF FOR THE WALDO AREA IS IN EXCESS OF ONE INCH...SO THE BURN SCAR WILL REMAIN UNDER THE GUN THROUGH THU... DURING THE TIME OF OUR FLASH FLOOD WATCH. MUCH OF THE ERN PLAINS WILL BE SOCKED IN WITH CLOUDS AND PRECIP AS UPSLOPE FLOW PERSISTS. THIS WILL LIMIT CONVECTIVE POTENTIAL OVER THE PLAINS AND COULD MEAN MORE OF A STRATIFORM EVENT...HOWEVER ISOLD TS WILL REMAIN A THREAT PARTICULARLY ALONG AND NR THE MTS. THERE WILL ALSO BE A LOW RISK OF SOME STRONG OR SVR CONVECTION OVER THE ERN PLAINS EARLY WED EVE. MOST OF THE HEAVIER CONVECTION SHOULD BE E OF OUR AREA AFTER 00Z WED...BUT ONE OR TWO STRONG STORMS COULD BE ONGOING OVER KIOWA COUNTY EARLY IN THE PERIOD. HAVE GONE ON THE LOW SIDE OF GUIDANCE FOR TEMPS ON THU...MAINLY UPPER 50S FOR THE PLAINS. H7 TEMPS WILL BE NR ZERO...AND WITH CLOUD COVER AND PRECIP DO NOT ANTICIPATE A LOT OF MIXING. SNOW LEVELS WILL REMAIN AROUND 9K FEET THROUGH THU FOR THE NRN RANGES...AND 10K FEET OR HIGHER FOR THE SW MTS. SO...EXPECT THE HEAVIER SNOW TOTALS TO BE ABOVE 11000 FEET...WITH SOME HEAVY WET SNOW FOR THE PASSES. HIGHEST ELEVATIONS SUCH AS PIKES PEAK AND THE HIGHER PEAKS IN THE SAWATCH AND SANGRES COULD SEE 1-2 FEET OF SNOW BY LATE THU. SNOW LEVELS COULD BRIEFLY DROP AS LOW AS 8 K FEET OR POSSIBLY LOWER IN HEAVIER SHOWERS. A BIT OF A RESPITE THU NIGHT INTO FRI MORNING BEFORE PRECIP CHANCES PICK UP AGAIN LATE FRI...AS A COLD FRONT RACES SWD THROUGH ERN CO. THIS WILL BRING ANOTHER PERIOD OF UPSLOPE TO THE PLAINS ON SAT. THE 12Z GFS ALSO SHOWS AN INFLUX OF DEEP MOISTURE INTO THE CENTRAL ROCKIES...ASSOCIATED WITH A SUBTROPICAL PLUME THAT WILL SLOWLY MOVE TO THE SE THROUGH EARLY NEXT WEEK. THIS MAY ACTUALLY END UP BEING AN EVEN GREATER THREAT FOR FLASH FLOODING...WITH THE POTENTIAL FOR STRONGER CONVECTION ALONG WITH THE HIGH PWATS. ENSEMBLE GRIDS REFLECT HIGH POPS THROUGH THIS PERIOD...AND SEE NO REASON TO CHANGE THEM AT THIS POINT. FOR THE WEEKEND...TEMPS WILL REMAIN BELOW AVERAGE...IN THE 60S FOR THE PLAINS AND 50S FOR THE MTS. FLOW SHOULD BECOME MORE W-SW FOR EARLY NEXT WEEK...WHICH WILL LEAD TO WARMER WX FOR THE AREA. ROSE && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 243 PM MDT TUE MAY 7 2013 AN UPPER LEVEL LOW PRESSURE SHIFTING FROM FAR NORTHWESTERN ARIZONA AT 00Z WEDNESDAY INTO SOUTHWESTERN COLORADO BY 00Z THURSDAY WILL BRING INCREASING CHANCES OF PRECIPITATION TO THE TAF SITES...ESPECIALLY ON WEDNESDAY. THE KALS...KCOS AND KPUB TAF SITES MAY EXPERIENCE MVFR/IFR CONDITIONS AT TIMES WEDNESDAY DUE TO HEAVIER SHOWER AND THUNDERSTORM ACTIVITY. && .PUB WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 6 AM MDT WEDNESDAY THROUGH THURSDAY AFTERNOON FOR COZ081-084-085. WINTER STORM WATCH FROM 7 AM MDT WEDNESDAY THROUGH THURSDAY EVENING FOR COZ058-060-073-075-080-082. && $$ UPDATE...MW SHORT TERM...77 LONG TERM...ROSE AVIATION...77
AREA FORECAST DISCUSSION
NWS PUEBLO CO
321 PM MDT MON MAY 6 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 308 PM MDT MON MAY 6 2013 UPPER DISTURBANCE LIES JUST TO THE SOUTH OF CO WITH BANDS OF CONVECTION ACROSS NORTHERN NEW MEXICO LIFTING NORTHWARD AHEAD OF THIS FEATURE. WE`VE HAD PERSISTENT -SHRASN ACROSS THE MOUNTAIN AREAS TODAY...PARTICULARLY ALONG THE CONTDVD WHERE KMYP AND KCPW WEB CAMS CONTINUE TO SHOW WET SNOW FALLING. KALS HAS ALSO PICKED UP A BRIEF RAIN SHOWER...AND EVEN KTAD REPORTED SOME LIGHT RAIN WITH A BAND THAT MOVED OFF THE MOUNTAINS EARLIER THIS AFTERNOON. MEANWHILE...SFC DEW POINTS ACROSS THE PLAINS HAVE BEEN SLOW TO COME UP WITH READINGS STILL IN THE LOWER TO MID 20S FOR MOST AREAS. AS THE SHORTWAVE CONTINUES TO TRACK TO THE NORTH ACROSS THE AREA THIS EVENING...WILL CONTINUE HIGH POPS ACROSS THE MOUNTAINS WITH AXIS OF HIGHEST POPS SHIFTING INTO THE NORTH CENTRAL MOUNTAINS THROUGH THE EVENING. ACROSS THE PLAINS WILL KEEP GENERALLY ISOLATED POPS IN THE FCST AS HRRR LOOKS OVERDONE WITH QPF FIELDS GIVEN THE SLOW REBOUND IN SFC DEW POINTS. THE TWO DIVIDES...PALMER AND RATON...HAVE THE BEST CHANCE AT SEEING SOME MEASURABLE PRECIPITATION...SO WILL HOLD ON TO SOME SCT POPS FOR THESE AREAS. WILL BE CONTINUING TO WATCH THE WALDO CANYON BURN SCAR FOR RAINFALL. MOST LIKELY SCENARIO IS FOR QPF AMOUNTS TO RANGE UP TO .10...WHICH IS BELOW FLOOD ADVISORY THRESHOLDS. HOWEVER IF A STRONGER CELL DEVELOPS...THERE COULD BE SOME LOCAL AMOUNTS APPROACH .20. AS THE DISTURBANCE LIFTS NORTHWARD...SHOULD SEE IMPROVING CONDITIONS SPREAD FROM SOUTH TO NORTH OVERNIGHT WITH SOME CLEARING TAKING PLACE TOWARDS MORNING. HAVE POPS DROPPING INTO THE ISOLATED CATEGORY OVERNIGHT ACROSS THE CENTRAL AND SOUTHWEST MOUNTAINS AS FORCING IS WEAK AND WE LOOSE CONVECTIVE INGREDIENT. STILL LOOKS LIKE THE WARMEST DAY IS ON TAP FOR TUESDAY. ALTHOUGH SFC DEW POINTS WILL LIKELY RISE INTO THE 30S OVERNIGHT...THEY FALL AGAIN ACROSS THE SOUTHEAST PLAINS INTO THE 20S...WITH LCLS IN MODEL SOUNDINGS AROUND H6. FOR THAT REASON...THINK THAT SUB CLOUD DRY LAYER WILL KEEP ANY RAINFALL ON THE WALDO BURN SCAR FROM REACHING FLOOD ADVISORY CRITERIA ONCE AGAIN...WITH AMOUNTS LIKELY TO REMAIN UNDER .10. BUT WITH MORE SUNSHINE ON TUESDAY RESULTING IN BETTER POTENTIAL INSTABILITY...AND NAM12 HINTING AT A BOUNDARY STALLING ALONG THE PALMER DIVIDE IN THE AFTERNOON...WALDO WILL NEED TO BE MONITORED AS CELLS COULD POTENTIALLY BE STRONGER. OVER THE MOUNTAIN AREAS...KEPT POPS IN THE SCATTERED RANGE AS WE APPEAR TO LACK ANY STRONG FORCING ALOFT FOR MORE WIDESPREAD PCPN. OTHERWISE...HIGH TEMPERATURES SHOULD TOP OUT IN THE 70S ACROSS THE PLAINS...WITH 60S FOR THE VALLEYS...AND GENERALLY 40S AND 50S FOR THE MOUNTAINS. -KT .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 308 PM MDT MON MAY 6 2013 INCREASING CONCERNS FOR HEAVIER RAIN POTENTIAL(LOWER ELEVATION SHOWERS AND THUNDERSTORMS)...INCLUDING OVER THE WALDO CANYON BURN SCAR(ESPECIALLY FROM WEDNESDAY INTO THURSDAY) AS WELL AS INCREASING STRONG TO SEVERE WEATHER THREAT OVER PORTIONS OF THE SOUTHEASTERN COLORADO PLAINS FROM WEDNESDAY INTO WEDNESDAY NIGHT AND HIGHER ELEVATION SNOWS ARE PRIMARY LONGER TERM METEOROLOGICAL ISSUES. RECENT LONGER TERM COMPUTER SIMULATIONS SUGGEST THAT CLOSED UPPER LOW CENTERED OVER FAR SOUTHERN NEVADA AT 00Z WEDNESDAY MOVES INTO THE FOUR CORNERS REGION BY 00Z THURSDAY WITH LATEST ECMWF SOLUTION SLOWLY MOVING THE CLOSED UPPER LOW ACROSS SOUTHERN COLORADO INTO WESTERN KANSAS BY 06Z FRIDAY WHILE LATEST GFS SUGGESTS THAT CLOSED UPPER LOW WILL REMAIN IN THE VICINITY OF THE FOUR CORNERS REGION THROUGH THURSDAY BEFORE DROPPING UPPER LOW SOUTH INTO FAR SOUTHEASTERN ARIZONA BY 00Z SATURDAY. IN ADDITION...NORTHERLY SURGES(CAPABLE OF ENHANCING PRECIPITATION POTENTIAL) ARE PROJECTED TO MOVE ACROSS PRIMARILY EASTERN SECTIONS OF THE CWFA TUESDAY NIGHT...WEDNESDAY AND THEN AGAIN ON SATURDAY. BOTH ECMWF AND GFS SOLUTIONS GENERATE HEALTHY AMOUNTS OF PRECIPITATION OVER THE FORECAST DISTRICT THROUGH THURSDAY NIGHT...WITH OF COURSE THE GFS MODEL MUCH MORE AGGRESSIVE WITH RESPECT TO POTENTIAL TOTAL PRECIPITATION AMOUNTS. PRECIPITATION...HEAVY AT TIMES...WILL BE POSSIBLE OVER MANY PORTIONS OF THE FORECAST DISTRICT FROM TUESDAY NIGHT INTO AT LEAST THURSDAY NIGHT AND FLOOD WATCHES MAY BECOME NECESSARY FOR AREAS SUCH AS THE WALDO CANYON BURN SCAR(ESPECIALLY FROM WEDNESDAY INTO THURSDAY) IF METEOROLOGICAL TRENDS CONTINUE. WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY AND ISSUE HIGHLIGHTS/ADVISORIES AND/OR HYDRO WARNINGS IF/AS NEEDED. ANOTHER LONGER TERM CONCERN WILL BE THE POTENTIAL FOR STRONG TO SEVERE CONVECTION OVER PORTIONS OF THE SOUTHEASTERN COLORADO PLAINS...ESPECIALLY FROM WEDNESDAY INTO WEDNESDAY NIGHT AS DEEPER ATMOSPHERIC MOISTURE...LOCALIZED 0 TO 6 KM SHEARS AROUND 30 KNOTS...LOCALIZED CAPES AROUND 2100 J/KG AND LOCALIZED LIS AROUND -8C RESPECTIVELY ARE ANTICIPATED OVER PORTIONS(ESPECIALLY FAR EASTERN SECTIONS) OF THE SOUTHEASTERN COLORADO PLAINS. AS ALWAYS...WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY AND ISSUE SEVERE WEATHER PRODUCTS AS NEEDED. ACCUMULATING SNOW IS ALSO EXPECTED AT TIMES OVER HIGHER TERRAIN AREAS FROM TUESDAY NIGHT INTO LATER THIS WEEK. WINTER WEATHER HIGHLIGHTS MAY BECOME NECESSARY OVER HIGHER TERRAIN AREAS DURING THIS TIME-FRAME(ESPECIALLY OVER PUBLIC ZONES 58/60/66/68/73/75/81 AND 82). IMPROVING METEOROLOGICAL CONDITIONS IN THE FORM OF WARMING TEMPERATURES AND DECREASING POPS ARE THEN ANTICIPATED FROM LATER THIS WEEKEND INTO EARLY NEXT WEEK. COOLEST TEMPERATURES DURING THE LONGER TERM ARE EXPECTED TUESDAY AND WEDNESDAY WHILE WARMEST LONGER TERM TEMPERATURES ARE PROJECTED SUNDAY AND NEXT MONDAY. FINALLY... STILL ANTICIPATE THAT LOW-GRADE GRADIENT WINDS SHOULD CONTINUE OVER THE FORECAST DISTRICT DURING THE LONGER TERM. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 308 PM MDT MON MAY 6 2013 UPPER DISTURBANCE WILL SPREAD ISOLATED TO NUMEROUS SHOWERS ACROSS SOUTH CENTRAL AND SOUTHEAST CO THROUGH THE EVENING...WITH HIGHEST COVERAGE ACROSS THE MOUNTAIN AREAS. MOUNTAIN AREAS ALONG THE CONTDVD WILL CONTINUE TO SEE IFR CONDITIONS WITH LOCAL LIFR AND MTN OBSCURATIONS ACROSS THE HIGHER PEAKS IN -SHSN. THE SOUTHEAST MTS COULD SEE SOME IFR CONDITIONS AT TIMES THIS EVENING WITH -SHRASN AND EVEN SOME ISOLATED -TS. AS FOR THE TAF SITES...KALS WILL CONTINUE TO SEE THE POTENTIAL FOR -SHRA THROUGH THE EARLY EVENING WITH VFR TO MVFR CIGS AT TIMES. KCOS AND KPUB COULD SEE A PASSING SHOWER AFTER 21Z...HOWEVER PROBABILITY IS NOT AS GREAT AS LOW LEVEL MOISTURE HAS BEEN SLOW TO RETURN. CIGS SHOULD STAY IN THE VFR CATEGORY...THOUGH HIGHER TERRAIN NORTH AND WEST OF KCOS COULD SEE SOME MVFR CIGS IN -SHRA. CLEARING CONDITIONS CAN BE EXPECTED OVERNIGHT WITH A SUNNIER START TO THE DAY ON TUESDAY. ISOLATED TO SCATTERED AFTERNOON -TSRA HIGHER MTN -SHSN WILL DEVELOP OVER THE MOUNTAINS AGAIN WITH MVFR TO IFR CIGS. TAF SITES ARE MORE LIKELY TO REMAIN DRY WITH VFR CONDITIONS. KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1047 AM MDT MON MAY 6 2013 .UPDATE... && .SHORT TERM...CURRENT FORECASTS LOOK ON TRACK. WATER VAPOR LOOPS SHOWING SHORTWAVE MOVING INTO THE FOUR CORNERS REGION WITH ABUNDANT MOISTURE SPREADING NORTHEAST ACROSS MOUNTAINS. RADAR SHOWING SOME SHOWERS OVER PARK AND SUMMIT COUNTIES. SHOWERS APPEAR LIGHT BASED ON WEB CAMS. CURRENT TEMPERATURES SUGGESTING PERHAPS A MIX OF RAIN AND SNOW OVER SOUTH PARK WITH SNOW OVER THE HIGHER ELEVATIONS. MODELS SHOW THIS SHORTWAVE MOVING NORTHEAST ACROSS THE AREA DURING THE LATE AFTERNOON AND EVENING... WITH SHOWERS BECOMING MORE WIDESPREAD OVER THE MOUNTAINS. SOME SNOW POSSIBLE AROUND 11000 FEET...WITH MINIMAL ACCUMULATION. MODELS DO DELAY THE ONSET OF THE SHOWERS ACROSS THE PLAINS UNTIL AFTER 21Z. BUT WITH THE INCREASING LIFT AHEAD OF THE SHORTWAVE... IT IS POSSIBLE A FEW SHOWERS COULD SPREAD ACROSS THE URBAN CORRIDOR AND PALMER DIVIDE A BIT EARLIER. CURRENT FORECAST SHOWS THIS TREND...AND SEEMS MORE REASONABLE. AIRMASS TO BECOME MORE UNSTABLE DURING THE AFTERNOON WITH A FEW THUNDERSTORMS POSSIBLE. LATEST RAP DOES SHOW SOME VERTICAL SHEAR ACROSS THE PLAINS WITH SOUTHEAST SURFACE FLOW AND SOUTHWEST TO WEST FLOW ALOFT. BUT THE FLOW ALOFT LOOKS WEAK AND DOESN`T APPEAR ADEQUATE FOR SEVERE STORMS. A FEW STORMS SOUTHEAST AND EAST OF DENVER COULD BECOME STRONG ENOUGH TO PRODUCE SMALL HAIL AND GUSTY WINDS ALONG WITH BRIEF HEAVY RAIN LATE THIS AFTERNOON OR EARLY EVENING WITH PASSAGE OF THE SHORTWAVE. .AVIATION...WINDS HAVE BECOME LIGHT NORTHWEST ACROSS THE AREA AIRPORTS...SHOULD SHIFT TO THE NORTHEAST AROUND 18Z WITH SPEEDS AROUND 8 KTS. WINDS TO BECOME EASTERLY AROUND 22Z WITH SPEEDS INCREASING TO 15 KTS...COULD BE A BIT MORE SOUTHEAST AT KDEN AND KAPA. SCATTERED SHOWERS ALONG WITH ISOLATED STORMS WILL DEVELOP IN THE AREA AFTER 18Z. BEST CHANCE FOR STORMS AFFECTING THE AREA AIRPORTS STILL LOOKS BETWEEN 22Z AND 02Z. CONFIDENCE NOT HIGH ENOUGH FOR A TEMPO TSRA GROUP AT THIS TIME...WILL GO WITH VCTS FOR NOW. ALSO A SLIGHT CHANCE FOR CEILINGS AROUND 6000 FEET DURING THIS TIME FRAME...WILL LEAVE IN A TEMPO GROUP. SLIGHT CHANCE FOR STORMS TO PRODUCE SMALL HAIL AND WIND GUSTS TO 30 KTS...MAINLY SOUTHEAST OF KDEN AND KAPA. && .HYDROLOGY...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED THROUGH THE AFTERNOON AND EARLIER. SLIGHT CHANCE OF THE HEAVIER SHOWERS AND STORMS TO PRODUCE UP TO A QUARTER OF AN INCH OF RAIN IN ABOUT 45 MINUTES. THREAT OF SIGNIFICANT RUNOFF DUE TO THE RAINFALL STILL APPEARS LOW. && .PREV DISCUSSION... /ISSUED 441 AM MDT MON MAY 6 2013/ .CORRECTION FOR MISSING WORDS.. SHORT TERM....FAIRLY STRONG AND WELL DEFINED VORT LOBE/SHORTWAVE TROUGH SWINGING NORTHEASTWARD AROUND THE SOUTHEAST SIDE OF THE CLOSED UPPER LOW SPINNING OFF THE NORTHERN CALIFORNIA COAST WILL BE THE PRINCIPLE WEATHER MAKER FOR NORTH CENTRAL AND NORTHEAST COLORADO THIS AFTERNOON AND EVENING. EXTENSIVE CLOUD BAND ASSOCIATED WITH THIS FEATURE PRESENTLY OVER NORTHEAST ARIZONA/ WESTERN NEW MEXICO IS PROGGED TO REACH THE SOUTHWEST EDGE OF THE FORECAST AREA BY AROUND MIDDAY/18Z. PRIOR TO ARRIVE...WITH PLENTY OF MID AND HIGH LEVEL MOISTURE OUT AHEAD OF IT...SHOULD SEE A STEADY INCREASE IN CLOUD COVER OVER THE ENTIRE AREA THROUGH THE MORNING HOURS. IN ADDITION RELATIVELY LIGHT WEST-NORTHWEST 700-500MB FLOW OVER THE AREA ATTM SHOULD BECOME PROGRESSIVELY MORE SOUTHWESTERLY THRU THE MORNING...THEN SOUTHEASTERLY THIS AFTERNOON WITH THE SHORTWAVE TROUGH NEARING. ITS AT THIS TIME WHEN WE SHOULD SEE SHOWERS DEVELOPING OVER AND NEAR THE FRONT RANGE WITH AN INCREASE IN LOW AND MID-LEVEL MOISTURE. HOWEVER...ACCORDING TO THE WRF..NAM AND GFS MODELS...WOULD NOT EXPECT TO SEE SHOWERS AND THUNDERSTORMS FORMING ON THE PLAINS UNTIL LATE THIS AFTERNOON OR PERHAPS EARLY THIS EVENING. THAT/S WHEN MODEL POP AND QPF GUIDANCE NUMBERS PEAK. MEANWHILE IN THE HIGH COUNTRY...ALREADY SEEING ISOLATED SNOW SHOWERS UP ALONG THE CONTINENTAL DIVIDE PRODUCING LITTLE OR NO SNOW ACCUMULATION. SHOWERS WILL BECOME MORE WIDESPREAD BY THIS AFTERNOON WITH LIGHT SNOW ACCUMULATION POSSIBLE ABOVE 10 THOUSAND FEET BY LATE THIS EVENING. ATMOSPHERE ALSO EXPECTED TO BECOME SUFFICIENTLY UNSTABLE TO PRODUCE AT LEAST ISOLATED THUNDERSTORMS IN THE HIGH COUNTRY. SAME GOES FOR THE MTN VALLEYS AND NORTHEAST PLAINS. STABILITY AND VERTICAL SHEAR ON PLAINS ACCORDING TO MODELS...DO NOT APPEAR ADEQUATE FOR SEVERE T-STORMS...BUT WE COULD SEE A FEW STORM CELLS...ROUGHLY SOUTH OF A BRIGGSDALE TO DENVER LINE...PRODUCING SMALL HAIL...BRIEF HEAVY RAIN AND STRONG GUSTY WINDS WITH PASSAGE OF THE SHORTWAVE LATE THIS AFTERNOON/EARLY THIS EVENING. BY LATE EVENING...PRECIP WILL QUICKLY DIMINISH FROM SOUTHWEST TO NORTHEAST AS THE WAVE EXITS THE AREA. ALTHOUGH THERE SHOULD STILL BE A FAIR AMOUNT OF CLOUD AROUND WITH A MOIST SOUTHWESTERLY FLOW OVER THE AREA. HIGH TEMPERATURES TODAY A FEW DEGS WARMER THAN YESTERDAY WITH THE MODEST WARMING ALOFT AHEAD OF THE SHORTWAVE. SEE LITTLE OR NO CHANGE IN OVERNIGHT TEMPERATURES. LONG TERM...THIS UPCOMING WEEK WILL BE CHARACTERIZED AS UNSETTLED WITH RATHER COOL TEMPERATURES AND SHOWERY CONDITIONS. THE MAIN WEATHER FEATURE WILL BE A BROAD LOW PRESSURE SYSTEM WHICH IS NOW OFF THE NORTHERN CALIFORNIA COAST. BY TUESDAY...MODEL CONSENSUS HAS THE LOW SLOWLY MOVING INLAND INTO SOUTHERN NEVADA AND THEN INTO THE 4 CORNERS AREA ON WEDNESDAY. LONG RANGE MODELS BEGIN TO DIVERGE ON THE TRACK AFTER WEDNESDAY AS THE GFS IS THE SLOWEST MODEL AND NOW ACTUALLY RETROGRADES THE LOW BACK INTO THE DESERT SOUTHWEST ON FRIDAY...WHILE THE FASTER EUROPEAN AND CANADIAN RUNS MOVE THE WEAKENING LOW INTO THE CENTRAL PLAINS. THIS A BIT OF A FLIP FLOP BETWEEN THE EUROPEAN AND GFS FROM A FEW RUNS AGO. AS FOR THE DETAILS...TUESDAY WILL HAVE WEAK DESCENT IN THE WAVE OF MONDAY NIGHTS EXITING WAVE WITH LOWER POPS FOR EARLY IN THE DAY ON TUESDAY. THERE WILL BE ENOUGH LINGERING MOISTURE FOR SCATTERED SHOWERS THOUGH ON TUESDAY AFTERNOON/EVENING. THE CHANCES OF RAIN INCREASE ON WEDNESDAY AND WEDNESDAY NIGHT AS COLORADO WILL BE UNDER INCREASING ASCENT FROM THE LOW AND DEEPENING EASTERLY FLOW. MOST OF THE MODEL QPF OUTPUT SHOWING 1-2 INCHES OF RAIN OVER PORTIONS OF THE NORTHEAST PLAINS. GFS HAS EVEN SOME HIGHER AMOUNTS BUT THIS SEEMS OVERDONE. BY FRIDAY...THE FLOW WILL BECOME MORE NORTH TO NORTHWEST WITH ADDITIONAL ENERGY TO EFFECT COLORADO FRIDAY AND EARLY SATURDAY. FINALLY BY LATE SATURDAY AND SUNDAY A DRIER AIRMASS BEGINS TO WORK IN FROM THE NORTHWEST WITH HIGH PRESSURE BUILDING ALOFT. AVIATION...VFR CONDITIONS ANTICIPATED AT DENVER AREA AIRPORTS THROUGH 21Z TODAY. AFTER 21Z...SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED TO DEVELOP IN THE AREA. THERE IS A SLIGHT CHANCE THAT STORMS BETWEEN 22Z AND 02Z COULD PRODUCE SMALL HAIL...WIND GUSTS TO 30 KTS AND BRIEF HEAVY RAINFALL. HOWEVER...AREAS EAST AND SOUTHEAST OF THE DENVER AREA HAVE A BETTER CHANCE OF THIS OCCURRING. COULD SEE CIGS LOWERING TO 5000-6000 FT AGL WITH PASSING SHOWERS. CONDITIONS WILL IMPROVE DURING THE EVENING WITH VFR CONDITIONS AND AN END TO PRECIPITATION BY 21Z OR 22Z IN THE DENVER AREA. HYDROLOGY...THE HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS LATE THIS AFTERNOON WILL HAVE THE POTENTIAL TO PRODUCE UP TO A QUARTER INCH OF RAIN IN 45 MINUTES. AT THIS TIME...THE THREAT OF HEAVY RUNOFF DUE TO THIS RAINFALL APPEARS LOW. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....ENTREKIN AVIATION...D-L
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
919 PM EDT TUE MAY 7 2013 ...COOLER WITH A LOW CHANCE OF A PASSING SHOWER TONIGHT... .UPDATE...THE PERSISTENT UPPER LEVEL LOW WAS NEARLY STATIONARY OVER NC/VA WHILE SPOKES OF ENERGY CONTINUED TO ROTATE AROUND THE VORTEX OVER THE DEEP SOUTH. MOSTLY CLEAR SKIES WERE OVER SE GA AND SOUTH OF I-10...WHILE MID CLOUDS WITH SCT-BKN DECKS BETWEEN 5-7 KFT WERE IMPACTING DUVAL AND NORTHERN CLAY COUNTIES WITH LIGHT RAIN AT BOTH CECIL FIELD AND MAYPORT WITHIN THE PAST HOUR. THE CONVECTION WAS FORMING WITHIN A W-E BAND OF CONVERGENCE UNDER A LOBE OF UPPER ENERGY EXTENDING SOUTH OF THE UPPER LOW...AND THE UPSTREAM TRAJECTORY OF THIS ENERGY EXTENDED OVER THE FL PANHANDLE AND SOUTHERN AL. WITH THE LOSS OF HEATING/INSTABILITY...WILL CONTINUE ADVERTISE FADING PRECIP THROUGH MIDNIGHT BUT SKIES BECOMING PARTLY CLOUDY OVER NE FL THROUGH THE NIGHT. ALSO INTRODUCED SOME PATCHY FOG OVER INLAND NE FL WHERE MOISTURE POOLING NEAR THE LINGERING CONVERGENT LINE AND WSW FLOW MAY ENABLE SOME LOW CIGS AND FOG TO FORM. ADJUSTED MIN TEMPS TO REFLECT COOLER VALUES IN THE LOWER 50S OVER SE GA WHERE THE GRADIENT WILL BE LIGHTER AND SKIES MOSTLY CLEAR...WHILE WARMER GULF FLOW AND PASSING CLOUDS SHOULD KEEP FL WARMER WITH MINS IN THE MID 50S INLAND TO LOW 60S COAST. && .AVIATION...LIGHT RAIN SHOWERS NEAR VQQ AND CRG ALONG A SURFACE TROUGH WILL MOVE OFFSHORE BEFORE MIDNIGHT. CIGS AROUND 5KFT AT JAX...CRG...AND VQQ WILL BECOME SCATTERED AFTER 03Z. PATCHY LIGHT FOG POSSIBLE MAINLY AT VQQ AND GNV 09Z-12Z. VFR CONDITIONS EXPECTED AGAIN ON WEDNESDAY. && .MARINE...BUOY 41012 INCREASED QUICKLY LAST HOUR TO 19G23KTS. BOTH THE GFS AND RUC INDICATE A BRIEF SMALL CRAFT EXERCISE CAUTION PERIOD BETWEEN 00Z AND 06Z OVER OUR OFFSHORE FL WATERS WITH WINDS 15-20 KTS. WILL AWAIT THE 01Z OB...AND IF BUOY 41012 CONTINUES NEAR SCEC CONDITIONS...WILL INTRODUCE A HEADLINE. RIP CURRENTS: LOW RISK ON WED. && .PRELIMINARY POINT TEMPS/POPS... AMG 52 83 59 86 / 10 10 10 10 SSI 60 77 64 81 / 10 10 10 10 JAX 58 82 60 85 / 20 10 10 10 SGJ 61 79 62 81 / 20 10 10 10 GNV 56 83 58 86 / 10 10 10 10 OCF 57 83 59 87 / 10 10 10 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ ENYEDI/ZIBURA/WALKER
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
730 PM EDT TUE MAY 7 2013 .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... MAIN FORECAST CONCERN IN THE SHORT TERM IS ASSOCIATED WITH SOME LINGERING MOISTURE AND WEAK VORT MAXS ROTATING AROUND THE PERSISTENT UPPER LOW CURRENTLY SITUATED ACROSS THE CAROLINAS. SO FAR THIS AFTERNOON...IT HAS ALLOWED FOR ENHANCED CU FIELD DEVELOPMENT AND SOME ISOLATED SHOWERS AND STORMS JUST EAST OF THE CWA. THERE IS ENOUGH ELEVATED INSTABILITY TO MAINTAIN THE LOW END CHANCE FOR ISOLATED THUNDERSTORMS MAINLY ACROSS PORTIONS OF THE EAST THROUGH THE REST OF TODAY. FOR TONIGHT...POPS SHOULD BE ON THE DECREASE ACROSS THE NORTHEAST. WITH GUIDANCE LIKELY UNDERDOING THE SFC MOISTURE PRESENT FROM RECENT RAINFALL...THERE IS A GOOD CHANCE FOR FOG DEVELOPMENT UNDER THE CALM TO LIGHT WINDS IN THE EARLY MORNING HOURS. GUIDANCE IS IN GENERAL AGREEMENT WITH SOME LOW LEVEL MOISTURE ADVECTING INTO THE FAR NORTHERN PORTION NEAR 12Z. SHORT RANGE ENSEMBLE RESTRICTED VSBY PROBS AND RUC CONDENSATION PRESSURE DEFICIT SUPPORT THE GREATEST CHANCE FOR MORE WIDESPREAD FOG DEVELOPMENT TO BE IN THE FAR NORTH OR NORTHWEST. CONFIDENCE IS LOW AT THIS POINT ON DENSE FOG DEVELOPMENT AND WILL MENTION PATCHY FOG AREA-WIDE FOR NOW. AS UPPER LOW FINALLY BEGINS ITS EXIT NEWD AND WEAK RIDGING TEMPORARILY BUILDS IN...HAVE TRENDED POPS TO MAINLY BE FOCUSED IN THE FAR NORTH AND NORTHEAST THROUGH WEDNESDAY NIGHT. FORECAST MUCAPE VALUES SUGGEST ISOLATED THUNDERSTORM DEVELOPMENT IS POSSIBLE AGAIN DURING THE AFTERNOON WEDNESDAY. FOR TEMPS...A GENERAL BLEND IN THE SHORT TERM GUIDANCE LOOKED REASONABLE AS THE FORECAST AREA SHOULD CONTINUE A GRADUAL WARM-UP AHEAD OF THE NEXT SYSTEM DURING THE WEEKEND. BAKER .LONG TERM /THURSDAY THROUGH TUESDAY/... HAVE MADE NO CHANGES TO THE EXTENDED. MODELS AGREE O BRIEF BREAK FOR MUCH OF THE CWA WEDNESDAY NIGHT INTO THURSDAY WITH RAIN CHANCES INCREASING AGAIN ON FRIDAY. SERIES OF SHORT WAVES SHOULD KEEP CHANCE OF RAIN ACROSS THE FORECAST AREA THROUGH SUNDAY...WITH DRYING SUNDAY INTO MONDAY WITH PASSAGE OF A SURFACE FRONT. HAVE INCLUDED THE PREVIOUS LONG TERM DISCUSSION BELOW. 41 LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... /ISSUED AT 411 AM EDT TUE MAY 7 2013/ BY WEDNESDAY NIGHT...PESKY UPPER LOW MOVES UP OVER THE MID ATLANTIC STATES...WITH RESIDUAL MOISTURE ACROSS NORTH AND NORTHEAST GEORGIA. BRIEF REPRIEVE EXPECTED ACROSS THE REMAINING CWA THURSDAY INTO FRIDAY AHEAD OF THE NEXT BATCH OF RAIN. EXTENDED MODELS STILL SHOWING COMBINATION OF ENHANCED MOISTURE FROM DEEP SOUTHERLY FLOW AND SERIES OF UPPER LEVEL DISTURBANCES WILL BRING BACK TO THE STATE BY FRIDAY AHEAD OF FRONT PUSHING THROUGH THE STATE OVER THE WEEKEND. HAVE OPTED TO INCREASE POPS SLIGHTLY FRIDAY...WITH GOOD CHANCE NORTH WITH SLIGHT CHANCE THROUGH THE METRO AREA. HAVE CONTINUED WITH INCREASING TREND INTO SATURDAY WITH LIKELY POPS NORTH AND GOOD CHANCE ACROSS MUCH OF THE REST OF THE AREA. THUNDERSTORMS LOOK TO BE LIKELY WITH THIS EVENT WITH GOOD MODEL AGREEMENT WITH THE INSTABILITY...ESPECIALLY SATURDAY. MODELS CONTINUE TO DIFFER ON THE AMOUNT OF QPF EXPECTED FRIDAY THROUGH SUNDAY...WITH THE WETTER ECMWF SHOWING LARGE PORTION OF WESTERN GEORGIA COULD SEE 0.75 TO 1.25 INCHES WITH ISOLATED HIGHER AMOUNTS...AND THE GFS SHOWING NORTH GEORGIA COULD SEE WIDESPREAD 0.5 INCHES...WITH PORTIONS OF NORTHWEST GEORGIA SEEING UP TO AN INCH. HAVE GENERALLY GONE WITH THE GFS SOLUTION FOR QPF...WHICH MAY BE WISHFUL THINKING AFTER THIS VERY WET WEEKEND ACROSS THE STATE. NEAR NORMAL TEMPERATURES ARE EXPECTED WEDNESDAY AND THURSDAY MORNING...WITH WARM UP BY WEDNESDAY AFTERNOON TO ABOVE NORMAL TEMPERATURES WHICH WILL REMAIN IN PLACE INTO THE WEEKEND. PRECIP ACTIVITY SATURDAY AND SUNDAY WILL KEEP TEMPERATURES CLOSER TO SEASONAL. 31 && AVIATION... 00Z UPDATE... ANY ISOLATED SHOWER ACTIVITY IS EXPECTED TO REMAIN NORTH OF THE TAF SITES THROUGH THIS FORECAST PERIOD. VF CONDITIONS ARE EXPECTED TO PREVAIL THROUGH 06Z WITH SCATTERED MVFR VISIBILITIES DEVELOPING 06Z THROUGH 15Z. LOCAL AREAS OF IFR OR EVEN LIFR VISIBILITIES ARE POSSIBLE BETWEEN 09Z AND 13Z...BUT ONLY TAF SITE WITH A HIGH POTENTIAL FOR AN EXTENDED PERIOD OF IFR CONDITIONS APPEARS TO BE KAHN AT THIS TIME. WINDS WILL REMAIN WESTERLY...GENERALLY 6KT OR LESS THROUGH 15Z...INCREASING TO 6-10KT BY 18Z. //ATL CONFIDENCE...00Z UPDATE... MEDIUM CONFIDENCE ON POTENTIAL FOR EARLY MORNING FOG. HIGH CONFIDENCE ALL ELSE. 20 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 51 78 56 84 / 20 20 10 10 ATLANTA 54 77 59 81 / 10 10 5 10 BLAIRSVILLE 49 71 51 77 / 30 30 20 20 CARTERSVILLE 50 76 54 81 / 10 10 10 10 COLUMBUS 54 80 60 85 / 5 10 5 5 GAINESVILLE 52 74 56 80 / 20 20 20 10 MACON 49 79 56 84 / 10 10 10 5 ROME 50 77 53 83 / 10 10 10 10 PEACHTREE CITY 48 78 53 82 / 10 10 5 5 VIDALIA 55 80 61 85 / 5 10 10 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BAKER LONG TERM....41 AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
719 PM EDT TUE MAY 7 2013 .SYNOPSIS... AN UPPER LEVEL LOW WILL CONTINUE TO DRIFT TO OUR NE THROUGH THURSDAY...GRADUALLY REDUCING OUR RAIN CHANCES. EXPECT MOISTURE INCREASE AND THE NEXT FRONTAL SYSTEMS TO AFFECT OUR REGION LATE FRIDAY THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LATE THIS AFTERNOON...SOME DRIER AIR ENTERED THE REGION FROM THE WEST AROUND THE UPPER LOW TO THE NORTH IN NORTH CAROLINA. WITH AN AREA OF SHOWERS AND MAYBE AN EMBEDDED THUNDERSTORM OR TWO MOVING SOUTHEAST INTO THE NORTH PART OF THE FORECAST AREA AND LAPS LIS -4 AND RUC13 SHOWING FAIRLY HIGH POPS IN THE NORTH DECIDED TO INCREASE POPS TO 60-80 PERCENT NORTH FOR 2-3 HOURS AND 30-50 PERCENT CENTRAL AND SOUTH PORTION. THERE WERE SEVERAL REPORTS OF SMALL HAIL AND ONE OF DIME SIZED HAIL IN RICHLAND COUNTY. WILL DROP POPS BACK TO 20-30 PERCENT THIS EVENING AS SUN GOES DOWN AND SURFACE HEATING DIMINISHES. OTHERWISE... AFTERNOON TEMPERATURES STILL OK. TONIGHT...UPPER LEVEL STAYS TO THE NORTH AND LEFTOVER LOW LEVEL MOISTURE MAY LEAD TO SOME FOG DEVELOPMENT AFTER MIDNIGHT. HOWEVER WIDESPREAD DENSE FOG IS NOT ANTICIPATED AT THIS TIME. CONSENSUS OVERNIGHT LOWS IN THE LOWER 50S WERE CONTINUED. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... UPPER LOW WILL SLOWLY DRIFT TO THE NE ACROSS THE MID ATLANTIC REGION AND INTO NEW ENGLAND. LINGERING TROUGHINESS AND WEAK IMPULSES IN ITS WAKE WILL REMAIN ALONG THE EAST COAST. PRECIPITABLE WATER VALUES ARE PROGGED TO REMAIN AROUND OR JUST OVER ONE INCH...NEAR CLIMO. BEST MOISTURE AND LOWER UPPER HEIGHTS/TEMPS WILL BE ACROSS OUR NORTHERN FA. PREMISE FOR LESS MID AND UPPER CLOUDINESS AND WARMER TEMPS COULD RESULT IN WEAK DIURNAL INSTABILITIES...AND POTENTIAL FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. CHANCE POPS FAVORING THE NORTHERN FA APPEAR IN ORDER. MODEL POPS LOWER THU...GIVEN EXPECTATIONS OF LESS INSTABILITY AS UPPER HEIGHTS/TEMPS CONTINUE TO RISE. FORECAST SOUNDINGS INDICATE WEAK DIURNAL INSTABILITY...BUT INDICATIONS OF WEAK NVA PSBL BY AFTN. ISO TO SLIGHT CHANCE SHOWER POSSIBLE...BUT DID NOT INCLUDE AT THIS TIME DUE TO LOW CONFIDENCE. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... GFS/ECMWF INDICATE WEAK UPPER RIDGE OVER THE EAST COAST THU NT/FRIDAY...TO BE REPLACED BY UPPER TROUGH OVER THE EASTERN CONUS FRI NT THRU MONDAY. MODELS PROG MOISTURE INCREASE FOR OUR REGION AHEAD OF A WEAK FRONT BY LATE FRI...WITH ADDITIONAL MOISTURE AND A STRONGER FRONT COMING IN OVER THE WEEKEND. MODEL CONSENSUS INDICATES CHANCE POPS IN ORDER. MODELS AGREE ON PUSHING THE FRONT OFFSHORE BY MON WITH HIGH PRESSURE BUILDING IN THROUGH EARLY NEXT WEEK. ACCEPTED BLEND OF MOS AND HPC GUIDANCE. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... LOW PRESSURE CONTINUES TO SPIN TO THE NORTH OF THE REGION. SOME DRIER AIR ENTERED FROM THE WEST. SOME CONVECTIVE ACTIVITY IS SITUATED NORTH OF THE TAF SITES BUT IS STARTING TO DIMINISH WITH THE LOSS OF HEATING. THERE MAY BE A FEW SHOWERS IN THE VICINITY OF CAE AND CUB THROUGH ABOUT 02Z THIS EVENING BUT EXPECT VFR CONDITIONS TO PERSIST THROUGH MUCH OF THE NIGHT. DRIER AIR AND LOW LEVEL WINDS BELOW 1 KFT SOUTHWEST 10-15 KNOTS SHOULD PREVENT MUCH FOG FROM DEVELOPING. HOWEVER...WITH A FAIRLY WET GROUND DECIDED TO GO 6 MILES IN GROUND FOG MOST TAF SITES. ALSO...WITH SCATTERED CLOUDS...AGS AND OGB WILL PROBABLY HAVE A BRIEF PERIOD OF MVFR VISIBILITIES 3-5 MILES IN SOME GROUND FOG. THIS MVFR CONDITIONS SHOULD BE SHORT LIVED AS THE MORNING SUN IS EXPECTED TO IMPROVE CONDITIONS TO VFR DURING THE 12Z-14Z TIME PERIOD OF WEDNESDAY MORNING. AFTER 14Z...MAINLY VFR CONDITIONS BUT COULD NOT RULE OUT A LATE AFTERNOON SHOWER OR POSSIBLY A THUNDERSTORMS BUT NOT CONFIDENT ENOUGH TO PLACE IN TAFS. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE SATURDAY AND SATURDAY NIGHT AS A COLD FRONT MOVES INTO THE REGION. && .HYDROLOGY... RIVER FLOOD WARNINGS CONTINUE AT SEVERAL LOCATIONS. DETAILS CAN BE OBTAINED FROM OUR RIVER FLOOD STATEMENTS...ON OUR WEBSITE...AND ON NOAA WEATHER RADIO. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
339 AM CDT MON MAY 6 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 339 AM CDT MON MAY 6 2013 11-3.9 MICRON MICROWAVE IMAGERY INDICATES A STRATUS LAYER STRETCHING FROM NORTH TO SOUTH ACROSS EASTERN NEBRASKA...EASTERN KANSAS...WESTERN IOWA...AND WESTERN MISSOURI. THE GENERAL THOUGHT IS THAT THE STRATUS WILL RESIDE ALONG AND EAST OF A SURFACE RIDGE AXIS...WHICH IS CURRENTLY SITUATED IN E NEB AND E KANSAS. AS THIS SURFACE RIDGE SCOOTS EASTWARD EXPECT THE STRATUS TO MOVE OUT WITH IT. CLOUDS MAY ALSO BREAK UP LATER TODAY AS LOW LEVEL MIXING COMMENCES AFTER SUNRISE. DAYTIME HIGHS TODAY ARE SOMEWHAT DEPENDENT ON HOW THE STRATUS BEHAVES. LEANED MORE IN THE DIRECTION OF EARLY STRATUS DISSIPATION AS THE SATURATED LAYER RESPONSIBLE FOR THE CLOUD COVER IS RATHER THIN. OVERNIGHT TONIGHT STRONG WARM AIR ADVECTION AHEAD OF A DEEPENING LEE SIDE SURFACE TROUGH WILL KICK UP A FEW SHOWERS AND THUNDERSTORMS ACROSS WESTERN/CENTRAL KANSAS...SOME OF WHICH MAY SPILL INTO THE FAR WESTERN ZONES EARLY TUESDAY MORNING...ALTHOUGH THE BULK OF THE ACTIVITY LOOKS TO REMAIN WELL WEST OF THE FORECAST AREA THROUGH THE OVERNIGHT HOURS MONDAY NIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 339 AM CDT MON MAY 6 2013 FOR TUESDAY THROUGH FRIDAY...MODELS CONTINUE TO SHOW A CONDITIONALLY UNSTABLE ATMOSPHERE WITH WEAK PERTURBATIONS POTENTIALLY MOVING THROUGH THE WEAK FLOW ALOFT. WEDNESDAY NIGHT AND THURSDAY CONTINUE TO LOOK LIKE THE TIME WHEN PRECIP IS MOST LIKELY AS THE CLOSED LOW CURRENTLY ON THE WEST COAST MOVES OUT FROM THE ROCKIES AND BRING AN INVERTED TROUGH AXIS INTO THE FORECAST AREA. FORCING FROM THE UPPER LOW AND LOW LEVEL CONVERGENCES ALONG THE SURFACE TROUGH LOOK TO PRODUCE CONDITIONS LIKELY FOR PRECIP. OTHERWISE PRECIP CAN NOT BE RULED OUT FOR ANY DAY SINCE MODELS SHOW LITTLE INHIBITION TO CONVECTION AND THE POTENTIAL FOR WEAK DISTURBANCES TO SPARK SOMETHING. HAVE NOT MADE MANY CHANGES FROM THE PREV FORECAST WITH POPS THROUGHOUT THE PERIOD AND MILD TEMPS WITH LOWS IN THE 50S AND HIGHS IN THE 70S. BY FRIDAY...THE MEDIUM RANGE MODELS BEGIN TO AMPLIFY AN UPPER LEVEL RIDGE ALONG THE WEST COAST. THIS SHOULD ALLOW FOR NORTHERN STREAM ENERGY TO DIG SOUTH AND FOR A MID LEVEL TROUGH OVER THE GREAT LAKES AND NORTHWEST FLOW ACROSS THE NORTHERN AND CENTRAL PLAINS. THERE IS PRETTY GOOD AGREEMENT WITH THE MODELS THAT THIS AMPLIFICATION OF THE PATTERN WILL BRING A COLD FRONT THROUGH THE AREA SATURDAY WITH RIDGING BUILDING IN FOR SATURDAY NIGHT AND SUNDAY. SO HAVE SOME SMALL POPS IN FOR SATURDAY FOR THE FRONTAL PASSAGE WITH A DRY FORECAST SATURDAY NIGHT AND SUNDAY. TRENDED TEMPS DOWN FOR SATURDAY AND SUNDAY SINCE IT APPEARS THE AIRMASS BEHIND THE COLD FRONT SHOULD ORIGINATE FROM CANADA...WITH LOWS IN THE 40S AND HIGHS IN THE 60S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1151 PM CDT SUN MAY 5 2013 CONFIDENCE REMAINS LOW. SATELLITE DATA INDICATES TRANSIENT HOLES IN STRATUS...AS WELL AS SOME CLEARING OCCURRING ITS WESTERN EDGE. HEIGHTS GENERALLY LOWERING WITH TIME...THOUGH KTOP RECENTLY RAISED. MODELS GIVING LITTLE HELP...THOUGH RAP SEEMS THE CLOSEST WITH REALITY AND FOLLOWED IT THE CLOSEST. CLOUD-LEVEL WINDS APPEAR TO VEER AND WOULD PUSH STRATUS BACK WEST. SLOW DIURNAL COOLING SHOULD BRING AT LEAST KFOE TO IFR...THOUGH POSSIBLY ON THE IFR EDGE AT KTOP. SLOW IMPROVEMENTS SHOULD OCCUR BY 18Z. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...LEIGHTON LONG TERM...WOLTERS AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1151 PM CDT SUN MAY 5 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 340 PM CDT SUN MAY 5 2013 THE UPPER LEVEL LOW ALONG WITH THE SURFACE LOW WAS MOVING EASTWARD ACROSS NORTHERN MS LATE THIS AFTERNOON. THE LOW-LEVEL MOISTURE CONTINUED TO BROADLY WRAP AROUND THIS VERTICALLY STACKED SYSTEM WITH THE TRAJECTORY OF MOISTURE WRAPPING NORTHWESTWARD FROM THE OH RIVER VALLEY INTO EASTERN IA...WHERE THE MOISTURE TRAJECTORIES EXTENDED SOUTHWEST AND SOUTH INTO NORTHERN MO AND EXTREME EASTERN KS. AS A RESULT THE LOW STRATUS HAS STAYED IN PLACE ACROSS MOST OF THE CWA INTO THE AFTERNOON HOURS. THE SKIES HAVE JUST BEGUN TO CLEAR ACROSS NORTH CENTRAL KS WHERE TEMPERATURES HAVE WARMED UP TO NEAR 60. UNDER THE CLOUDS ACROSS THE EASTERN TWO THIRDS OF THE CWA...TEMPERATURES HAVE ONLY SLOWLY WARMED INTO THE UPPER 40S AND LOWER 50S. THE HIGHS TODAY ACROSS THE EASTERN HALF OF THE CWA WILL PROBABLY OCCUR AROUND 600 PM WHEN SKIES MAY BEGIN TO CLEAR. AS THE UPPER LEVEL LOW CONTINUES TO MOVE EAST INTO AL...THE CLEARING TREND SHOULD GRADUALLY PUSH EASTWARD ACROSS THE CWA DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. MOST AREAS SHOULD CLEAR OUT BY 9PM. HIGH CLOUDS WERE ROTATING AROUND AN H5 RIDGE ACROSS THE DESERT SOUTHWEST...AND MAY MOVE BACK INTO THE CWA DURING THE EARLY MORNING HOURS OF MONDAY. MOSTLY CLEAR SKIES TONIGHT ALONG WITH LIGHT WINDS WILL ALLOW AREAS OF GROUND FOG TO DEVELOP LATE TONIGHT. HOWEVER...IF THE HIGH CLOUDS ARE THICKER THEN THE GROUND FOG MAY BE QUITE PATCHY AND MAY ONLY FORM IN LOW-LYING AREAS...ALONG LAKES AND WITHIN RIVER VALLEYS. LOWS WILL ONLY DROP INTO THE LOWER TO MID 40S. MONDAY...ANY PATCHY FOG THAT FORMS BEFORE SUNRISE WILL QUICKLY MIX OUT BY 14Z. A SOUTHERN STREAM H5 RIDGE WILL MOVE EAST INTO THE SOUTHERN PLAINS BY AFTERNOON. SKIES WILL BE MOSTLY TO PARTLY SUNNY. THIS WILL ALLOW HIGHS TO WARM INTO THE UPPER 60S TO LOWER 70S. NORTH WINDS WILL BECOME LIGHT AND VARIABLE THROUGH THE AFTERNOON HOURS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 340 PM CDT SUN MAY 5 2013 A WEAK UPPER LEVEL RIDGE WILL BE IN PLACE OVER THE CENTRAL AND SOUTHERN PLAINS MONDAY NIGHT WITH THE EXITING UPPER LEVEL LOW PROGRESSING EASTWARD TOWARD THE SOUTHEASTERN U.S AND A SECOND UPPER LOW MOVING ONSHORE INTO THE SOUTHWESTERN U.S. MODELS CONTINUE TO SHOW A SHORTWAVE DEVELOPING ALONG THE NORTHERN EDGE OF THE RIDGE...BRINGING THE CHANCE FOR SOME SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA TUESDAY INTO WEDNESDAY. OTHERWISE... THE MAIN FOCUS IS ON THE SECOND UPPER LEVEL LOW AS IT PROGRESSES EASTWARD TOWARD THE CENTRAL PLAINS. WHILE THE MODELS ARE BEGINNING TO COME INTO BETTER AGREEMENT WITH THE SYNOPTIC SCALE TRENDS...THERE ARE STILL SOME DISCREPANCIES IN THE DETAILS OF THE BEST TIMING AND LOCATION FOR PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE END OF THE WEEK. AS A RESULT...CONTINUE TO HAVE THE MENTION OF POPS FOR MUCH OF THE CWA THROUGH SATURDAY. 12Z MODEL RUNS ARE SHOWING THE UPPER LOW MOVING INTO THE FOUR CORNERS REGION BY WEDNESDAY AND WEAKENING TO THE POINT THAT A WEAK POSITIVELY-TILTED TROUGH BEGINS TO FORM OVER THE ROCKIES AND CENTRAL CONUS BY THE END OF THE WEEK. THE SURFACE LOW ASSOCIATED WITH THIS SYSTEM WILL SLOWLY PROGRESS EASTWARD INTO THE CENTRAL PLAINS...WITH MODELS IN FAIRLY GOOD AGREEMENT IN HAVING THE LOW TRACK JUST SOUTH OF THE FORECAST AREA BY THE END OF THE WEEK AND INTO SATURDAY. AT THIS TIME...THE BETTER CHANCES FOR PRECIPITATION LOOK TO BE WEDNESDAY NIGHT THROUGH THURSDAY AS A FRONTAL BOUNDARY MAY TRACK SOUTHWARD THROUGH THE CWA. AN UPPER LEVEL RIDGE LOOKS TO DEVELOP ALONG THE PACIFIC COASTLINE BY FRIDAY AND SLOWLY MOVE EASTWARD...HELPING TO PUSH THE GRADUALLY DEEPENING UPPER LEVEL TROUGH EAST OF THE AREA BY THE LATTER PART OF THE WEEKEND. THUNDERSTORM POTENTIAL LOOKS TO DIMINISH TOWARDS THE END OF THE WEEK INTO THE WEEKEND AS INSTABILITY WEAKENS OVER THE AREA WITH THE EXITING SYSTEM. WHILE THERE IS STILL UNCERTAINTY WITH HOW QUICKLY THIS SYSTEM WILL EXIT THE AREA...HAVE CONTINUED TO TREND DOWNWARD WITH POPS FRIDAY NIGHT INTO SATURDAY WITH DRY CONDITIONS SATURDAY NIGHT AND SUNDAY. AS FOR TEMPERATURES...HIGHS MID TO LATE WEEK LOOK TO BE NEAR THE SEASONAL NORMALS IN THE LOWER TO MIDDLE 70S WITH SLIGHTLY COOLER CONDITIONS BY THE WEEKEND AS HIGHS DROP INTO THE MID/UPPER 60S. LOW TEMPERATURES LOOK TO BE IN THE 50S THROUGH THE END OF THE WEEK AND COOLING INTO THE 40S BY THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1151 PM CDT SUN MAY 5 2013 CONFIDENCE REMAINS LOW. SATELLITE DATA INDICATES TRANSIENT HOLES IN STRATUS...AS WELL AS SOME CLEARING OCCURRING ITS WESTERN EDGE. HEIGHTS GENERALLY LOWERING WITH TIME...THOUGH KTOP RECENTLY RAISED. MODELS GIVING LITTLE HELP...THOUGH RAP SEEMS THE CLOSEST WITH REALITY AND FOLLOWED IT THE CLOSEST. CLOUD-LEVEL WINDS APPEAR TO VEER AND WOULD PUSH STRATUS BACK WEST. SLOW DIURNAL COOLING SHOULD BRING AT LEAST KFOE TO IFR...THOUGH POSSIBLY ON THE IFR EDGE AT KTOP. SLOW IMPROVEMENTS SHOULD OCCUR BY 18Z. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GARGAN LONG TERM...HENNECKE AVIATION...65
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
850 PM EDT TUE MAY 7 2013 .UPDATE... ISSUED AT 830 PM EDT TUE MAY 7 2013 HOURLY POPS...TEMPS AND DEWPOINTS WERE UPDATED BASED ON RECENT TRENDS RADAR...SATELLITE AND MODEL TRENDS. SOME OF THE MODELS... PARTICULARLY RECENT HRRR...ARE HANDLING THE BAND OF SHOWERS MOVING ACROSS THE SOUTHWEST HALF OF THE CWA RATHER WELL. THE NAM AND THE GFS BRING ANOTHER WEAK SHORTWAVE AROUND THE MAIN CIRCULATION AND SPREAD SOME SHOWERS INTO THE SOUTHEASTERN COUNTIES LATER TONIGHT... TOWARD DAWN. THE NAM AND HRRR MINIMIZE THIS MORE THAN THE GFS AND CONFINE IT MORE TO FAR SOUTHEAST KY. NO THUNDER HAS BEEN OBSERVED OVER THE PAST HOUR SO WE HAVE OPTED TO REMOVE THUNDER FROM THE FORECAST OVERNIGHT. FOG HAS ALREADY DEVELOPED IN THE JKL VICINITY AND VALLEYS NEAR WHERE PRECIPITATION WAS HEAVIER IN THE EVENING. SO FOG SHOULD CONTINUE EARLIER THAN CLIMATOLOGY AND AND IF SKIES REMAIN CLEAR ENOUGH IT MAY BECOME DENSE AROUND OR SOON AFTER MIDNIGHT IN SOME AREAS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 359 PM EDT TUE MAY 7 2013 STACKED AND WEAKENING LOW PRESSURE WAS OVER THE CAROLINAS THIS AFTERNOON AND WAS MOVING NE. PRECIP ASSOCIATED WITH THE LOW WAS OVER WV AND ROTATING WESTWARD IN KY. MODELS SHOW IT TAKING A TURN TO THE SOUTHWEST AND THEN THE SOUTH THIS EVENING AS IT MOVES AROUND THE DEPARTING LOW. THIS PLACES THE GREATEST POTENTIAL FOR PRECIP IN OUR EASTERN COUNTIES THIS EVENING. THERE HAVE BEEN A FEW SPARSE LIGHTNING STRIKES TO OUR EAST...AND WITH MEAGER HEATING WHICH HAS TAKEN PLACE LOCALLY...WILL CARRY A SLIGHT CHANCE OF THUNDER HERE INTO THIS EVENING. AS HEATING IS LOST AND THE LOW SLOWLY MOVES AWAY...THERE SHOULD BE AN OVERALL DECREASE IN PRECIP OVERNIGHT. ON WEDNESDAY...HEATING SHOULD YIELD ENOUGH INSTABILITY TO CAUSE SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP OVER THE AREA ON THE EDGE OF THE DEPARTING LOW. WILL LOOK FOR A DIURNAL TREND...WITH THE ACTIVITY DYING OFF IN THE EVENING. THERE SHOULD BE MORE IN THE WAY OF CLEARING ON WEDNESDAY NIGHT AS MID/UPPER LEVEL RIDGING BUILDS IN. WITH RAIN LIKELY BEFORE THIS... FOLLOWED BY LIGHT WINDS...AND NO CHANGE IN SURFACE AIR MASS...THIS COULD RESULT IN QUITE A FOGGY NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 PM EDT TUE MAY 7 2013 MODELS ARE IN GOOD AGREEMENT THROUGH THE EXTENDED PORTION OF THE FORECAST. PESKY SLOW MOVING UPPER LEVEL LOW WILL FINALLY BE EXITING TO OUR NORTHEAST. SHORT WAVE RIDGING WILL BUILD IN BRIEFLY AT THE START OF THE PERIOD. BUT ANOTHER DISTURBANCE WILL MOVE QUICKLY INTO THE REGION FROM OUT OF THE SOUTHWESTERN CONUS TO FINISH OUT THE WEEK. THIS NEXT DISTURBANCE COMBINED WITH A LARGER...MORE ORGANIZED SYSTEM DROPPING SOUTHWARD OUT OF CANADA WILL KEEP UNSETTLED WEATHER IN THE FORECAST THROUGH MUCH OF THE UPCOMING WEEKEND. IN GENERAL... FORECAST SOUNDINGS ARE SHOWING ENOUGH SURFACE BASED INSTABILITY TO INCLUDE THUNDER WHENEVER POPS ARE MENTIONED THROUGH SATURDAY. THERE IS A DIURNAL FLAVOR TO SHOWER AND THUNDERSTORM ACTIVITY AS WELL. AM NOT CONVINCED SHOWER AND THUNDERSTORMS WILL BE AS PREVALENT AS RECENTLY ADVERTISED FOR THURSDAY. AFOREMENTIONED SHORT WAVE RIDGING APPEARS STRONG ENOUGH TO DEVELOP A CAP...SHOWING UP ON FORECAST SOUNDINGS THAT SHOULD HELP KEEP ACTIVITY LOW IF NOT AT A MINIMUM. A COUPLE OF THE MODELS...PARTICULARLY THE NAM DOES INDICATE A WEAK IMPULSE MOVING IN FROM THE WEST. QUESTION IS WILL IT BE STRONG ENOUGH TO LIFT OUT THE CAP. MODEL GUIDANCE IS SUGGESTING SLIGHT POPS. SO HAVE DECIDED TO SCALE BACK POPS FOR THURSDAY PROPER. LIKELY POPS APPEARS GOOD FOR FRIDAY...INTO THE BEGINNING OF THE WEEKEND. WILL TAPER POPS OFF QUICKLY SUNDAY AS A STRONG COLD FRONT CARRIES LINGERING SHOWERS OFF TO OUR EAST. OTHERWISE EXPECT NEAR NORMAL TEMPERATURES THROUGH FRIDAY. BUT SECOND MORE ORGANIZED SYSTEM THAT BRINGS THE STRONG COLD FRONT THROUGH OUR AREA SATURDAY NIGHT...OR EARLY SUNDAY MORNING WILL USHER IN ANOTHER ROUND OF MUCH COOLER AIR TO THE AREA TO FINISH OUT THE LONG TERM PORTION OF THE FORECAST. A SPECIAL NOTE THAT WITH HIGH PRESSURE CENTERED OVER OUR AREA MONDAY AND TUESDAY MORNINGS...CLEAR SKIES AND LIGHT WINDS...WE WILL HAVE TO KEEP AN EYE OUT FOR THE POTENTIAL FOR SOME PATCHY FROST AS OVERNIGHT LOWS WILL PROBABLY BOTTOM OUT IN THE MID 30S IN OUR TYPICALLY COLDER LOCATIONS BOTH MORNINGS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 840 PM EDT TUE MAY 7 2013 CONDITIONS VARIED WIDELY FROM VFR BELOW AIRPORT MINS AT TAF ISSUANCE DUE TO VIS REDUCTIONS IN FOG...ESPECIALLY AT JKL. DETERIORATION AS FOG CONTINUES TO DEVELOP DURING THE FIRST 6 HOURS WILL LEAD TO RATHER WIDESPREAD MVFR BY AROUND 05Z AND IFR OR WORSE IN AREAS THAT EXPERIENCED HEAVIER RAIN TODAY. VISIBILITY AND PROBABLY CEILING AS WELL ARE FORECAST TO FURTHER DROP...IFR POSSIBLE IN MANY AREAS BETWEEN 8Z AND 13Z AND DROPS TO NEAR OR BELOW AIRPORT MINS ARE POSSIBLE AT ALL THREE TAF SITES...BUT MOST LIKELY AT JKL. IMPROVEMENT TO MVFR IS THEN EXPECTED IN ALL AREAS BETWEEN 13Z AND 16Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...HAL LONG TERM...RAY AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
145 PM EDT MON MAY 6 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH WEDNESDAY MORNING. LOW PRESSURE APPROACHING FROM THE SOUTH WILL BRING SCATTERED SHOWERS TO THE AREA LATE WEDNESDAY THROUGH FRIDAY. ANOTHER LOW PRESSURE SYSTEM MOVES IN FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 130 PM UPDATE...NO CHANGES TO THE GOING FORECAST AT THIS TIME OTHER THAN TO ADD AREAS OF DENSE FOG IN AT THE COAST FOR TONIGHT. 1030 AM UPDATE...MINOR ADJUSTMENTS BASED ON LATEST TRENDS IN OBSERVATIONAL DATA. FOG/STRATUS HAS BURNED OFF OVER LAND...HOWEVER IT IS EXPECTED TO COME BACK IN...POSSIBLY AS EARLY AS LATE AFTERNOON ON THE MID COAST...AND THEN THE REST OF THE COAST THIS EVENING. TEMPS ON TRACK...LOWERED A BIT ON THE IMMEDIATE COAST. PREVIOUSLY... UPDATE...AS EXPECTED STRATUS IS ON THE DOORSTEP OF SRN NH ATTM. APPEARS AS THOUGH IT WILL NOT MAKE IT MUCH FARTHER N...HOWEVER VALLEY FOG IS PREVALENT ALONG THE COAST. THIS IS COVERED WELL IN THE GRIDS...SO HAVE MAINLY USED CURRENT OBS TO ADJUST TEMPS FOR THE NEXT SEVERAL HRS. HAVE ALSO USED THE LATEST HRRR TO REFINE WIND FORECAST FOR THE SEA BREEZE. PREVIOUS DISCUSSION...PERSISTENCE CONTINUES TO RULE THE FORECAST IN THE NEAR TERM. HIGH PRES CENTERED INVOF NOVA SCOTIA REMAINS IN CONTROL OF THE REGION. BEING CLOSER TO THE RIDGE AXIS...THE COASTAL AREAS ARE SEEING SOME OF THE BEST RADIATIONAL COOLING AS A RESULT. HAVE LEANED ON BIAS CORRECT MOS FOR MIN TEMPS...SEEING AS THIS STRETCH OF WX HAVE PROVIDED SUFFICIENT DATA AND SIMILAR CONDS. KEEPING AN EYE ON COASTAL STRATUS OVER SRN NEW ENGLAND EDGING NWD. TRACKING ITS CURRENT SPEED...IT WOULD ARRIVE OVER SRN NH AND SWRN ME NEAR 10 TO 12Z. HAVE SOME HINTS OF IT IN THE GRIDS...BUT NOT CONFIDENT IT TOTALLY MAKES IT TONIGHT. WILL HAVE TO WATCH MORE FOR PATCHY FOG IN THE LOW LYING AREAS AS TEMPS BOTTOM OUT. EXPECTED ANOTHER NICE DAY TODAY...AS TEMPS WARM QUICKLY IN DRY CONDS. HIGHS WILL CLIMB WELL INTO THE 70S INLAND...WITH SEA BREEZE/SLY FLOW KEEPING THE COAST CLOSER TO 60. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS RIDGE AXIS CONTINUES TO SLIDE EWD...MORE AND MORE SLY FLOW WILL HELP TRANSPORT LLVL MOISTURE NWD. NAM IS NOT AS BULLISH AS ECMWF/GFS/CMC...BUT GIVEN THE GRADUAL NWD DISPLACEMENT EACH NIGHT EXPECT THAT IT SHOULD REACH THE COAST TONIGHT. INLAND AREAS WILL REMAIN UNDER CLEAR SKIES. STRATUS COULD STIFLE EARLY WARMING ALONG THE COAST TUE...BUT EXPECT ANOTHER PLEASANT DAY WITH HIGHS IN THE 60S ALONG THE COAST AND 70S TO NEAR 80 INLAND. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... EXTREMELY DRY PATTERN FOR THIS TIME OF THE YEAR WILL GRADUALLY BECOME MORE SEASONAL AS WE HEAD INTO THE EXTENDED PORTION OF THE FORECAST. SLOW MOVING...CUTOFF...UPPER LEVEL LOW WILL SLOWLY MOVE NORTHEAST...WEAKENING AS IT APPROACHES NEW ENGLAND. THIS SYSTEM WILL ALLOW SCATTERED SHOWERS TO ENTER FAR SOUTHERN AREAS LATE WEDNESDAY...BEFORE THE LIGHT PCPN SPREADS NORTH. ALL MODELS ARE RELATIVELY SIMILAR IN THE POSITIONING OF THE SFC LOW AND MOISTURE COMING IN OFF THE BRINK DURING THE MID TO LATE PORTION OF THE WORK WEEK. AHEAD OF THIS PCPN...LOW CLOUDS WILL MOVE IN OFF THE GULF OF MAINE. THIS MOISTURE WILL END OUR PERIOD OF OUR LARGE DIURNAL RANGES FROM THE DAYTIME MAXES TO THE OVERNIGHT LOWS. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... SHORT TERM...LOW CHANCE THAT SOME COASTAL STRATUS ARRIVES ACROSS SRN NH AND SWRN ME NEAR DAYBREAK THIS MORNING. OTHERWISE VFR CONDS TO PREVAIL UNTIL AFTER 00Z TUE. IFR CONDS ARE EXPECTED FOR COASTAL TERMINALS AS CIGS AND POSSIBLY VSBYS DECREASE IN STRATUS. LONG TERM... MARINE FOG LOOKS LIKELY TUESDAY AND WEDNESDAY MORNINGS RESULTING IN SOME AREAS OF MVFR OR LOWER. SCATTERED SHOWERS ENTER THE REGION FROM SOUTH TO NORTH WEDNESDAY NIGHT THROUGH THE END OF THE WORK WEEK. && .MARINE... SHORT TERM...LONG PERIOD SWELL AROUND 5 FT WILL CONTINUE EARLY THIS MORNING. GIVEN LACK OF STEEPNESS TO THE SEAS...NO SCA IS EXPECTED. WINDS WILL REMAIN BLO 25 KT. LONG TERM... MARINE FOG IS LIKELY TUESDAY AND WEDNESDAY MORNINGS WITH POOR VISIBILITY. WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA. SEAS MAY BRIEFLY REACH 5 FT THURSDAY. && .FIRE WEATHER... HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER WITH NO RAIN EXPECTED THROUGH TUESDAY. DAYTIME RELATIVE HUMIDITY WILL APPROACH 25% AWAY FROM THE COAST BUT WINDS ARE EXPECTED TO REMAIN RELATIVELY LIGHT THROUGH THE PERIOD. A CHANCE FOR WETTING RAINS WILL ARRIVE LATER WEDNESDAY ACROSS THE SOUTH...AND BY THURSDAY FOR NORTHERN ZONES. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS ANZ152-154 TIL 2 AM TUESDAY. && $$ LEGRO/JC/MLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1035 AM EDT MON MAY 6 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH WEDNESDAY MORNING. LOW PRESSURE APPROACHING FROM THE SOUTH WILL BRING SCATTERED SHOWERS TO THE AREA LATE WEDNESDAY THROUGH FRIDAY. ANOTHER LOW PRESSURE SYSTEM MOVES IN FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 1030 AM UPDATE...MINOR ADJUSTMENTS BASED ON LATEST TRENDS IN OBSERVATIONAL DATA. FOG/STRATUS HAS BURNED OFF OVER LAND...HOWEVER IT IS EXPECTED TO COME BACK IN...POSSIBLY AS EARLY AS LATE AFTERNOON ON THE MID COAST...AND THEN THE REST OF THE COAST THIS EVENING. TEMPS ON TRACK...LOWERED A BIT ON THE IMMEDIATE COAST. PREVIOUSLY... UPDATE...AS EXPECTED STRATUS IS ON THE DOORSTEP OF SRN NH ATTM. APPEARS AS THOUGH IT WILL NOT MAKE IT MUCH FARTHER N...HOWEVER VALLEY FOG IS PREVALENT ALONG THE COAST. THIS IS COVERED WELL IN THE GRIDS...SO HAVE MAINLY USED CURRENT OBS TO ADJUST TEMPS FOR THE NEXT SEVERAL HRS. HAVE ALSO USED THE LATEST HRRR TO REFINE WIND FORECAST FOR THE SEA BREEZE. PREVIOUS DISCUSSION...PERSISTENCE CONTINUES TO RULE THE FORECAST IN THE NEAR TERM. HIGH PRES CENTERED INVOF NOVA SCOTIA REMAINS IN CONTROL OF THE REGION. BEING CLOSER TO THE RIDGE AXIS...THE COASTAL AREAS ARE SEEING SOME OF THE BEST RADIATIONAL COOLING AS A RESULT. HAVE LEANED ON BIAS CORRECT MOS FOR MIN TEMPS...SEEING AS THIS STRETCH OF WX HAVE PROVIDED SUFFICIENT DATA AND SIMILAR CONDS. KEEPING AN EYE ON COASTAL STRATUS OVER SRN NEW ENGLAND EDGING NWD. TRACKING ITS CURRENT SPEED...IT WOULD ARRIVE OVER SRN NH AND SWRN ME NEAR 10 TO 12Z. HAVE SOME HINTS OF IT IN THE GRIDS...BUT NOT CONFIDENT IT TOTALLY MAKES IT TONIGHT. WILL HAVE TO WATCH MORE FOR PATCHY FOG IN THE LOW LYING AREAS AS TEMPS BOTTOM OUT. EXPECTED ANOTHER NICE DAY TODAY...AS TEMPS WARM QUICKLY IN DRY CONDS. HIGHS WILL CLIMB WELL INTO THE 70S INLAND...WITH SEA BREEZE/SLY FLOW KEEPING THE COAST CLOSER TO 60. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS RIDGE AXIS CONTINUES TO SLIDE EWD...MORE AND MORE SLY FLOW WILL HELP TRANSPORT LLVL MOISTURE NWD. NAM IS NOT AS BULLISH AS ECMWF/GFS/CMC...BUT GIVEN THE GRADUAL NWD DISPLACEMENT EACH NIGHT EXPECT THAT IT SHOULD REACH THE COAST TONIGHT. INLAND AREAS WILL REMAIN UNDER CLEAR SKIES. STRATUS COULD STIFLE EARLY WARMING ALONG THE COAST TUE...BUT EXPECT ANOTHER PLEASANT DAY WITH HIGHS IN THE 60S ALONG THE COAST AND 70S TO NEAR 80 INLAND. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... EXTREMELY DRY PATTERN FOR THIS TIME OF THE YEAR WILL GRADUALLY BECOME MORE SEASONAL AS WE HEAD INTO THE EXTENDED PORTION OF THE FORECAST. SLOW MOVING...CUTOFF...UPPER LEVEL LOW WILL SLOWLY MOVE NORTHEAST...WEAKENING AS IT APPROACHES NEW ENGLAND. THIS SYSTEM WILL ALLOW SCATTERED SHOWERS TO ENTER FAR SOUTHERN AREAS LATE WEDNESDAY...BEFORE THE LIGHT PCPN SPREADS NORTH. ALL MODELS ARE RELATIVELY SIMILAR IN THE POSITIONING OF THE SFC LOW AND MOISTURE COMING IN OFF THE BRINK DURING THE MID TO LATE PORTION OF THE WORK WEEK. AHEAD OF THIS PCPN...LOW CLOUDS WILL MOVE IN OFF THE GULF OF MAINE. THIS MOISTURE WILL END OUR PERIOD OF OUR LARGE DIURNAL RANGES FROM THE DAYTIME MAXES TO THE OVERNIGHT LOWS. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... SHORT TERM...LOW CHANCE THAT SOME COASTAL STRATUS ARRIVES ACROSS SRN NH AND SWRN ME NEAR DAYBREAK THIS MORNING. OTHERWISE VFR CONDS TO PREVAIL UNTIL AFTER 00Z TUE. IFR CONDS ARE EXPECTED FOR COASTAL TERMINALS AS CIGS AND POSSIBLY VSBYS DECREASE IN STRATUS. LONG TERM... MARINE FOG LOOKS LIKELY TUESDAY AND WEDNESDAY MORNINGS RESULTING IN SOME AREAS OF MVFR OR LOWER. SCATTERED SHOWERS ENTER THE REGION FROM SOUTH TO NORTH WEDNESDAY NIGHT THROUGH THE END OF THE WORK WEEK. && .MARINE... SHORT TERM...LONG PERIOD SWELL AROUND 5 FT WILL CONTINUE EARLY THIS MORNING. GIVEN LACK OF STEEPNESS TO THE SEAS...NO SCA IS EXPECTED. WINDS WILL REMAIN BLO 25 KT. LONG TERM... MARINE FOG IS LIKELY TUESDAY AND WEDNESDAY MORNINGS WITH POOR VISIBILITY. WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA. SEAS MAY BRIEFLY REACH 5 FT THURSDAY. && .FIRE WEATHER... HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER WITH NO RAIN EXPECTED THROUGH TUESDAY. DAYTIME RELATIVE HUMIDITY WILL APPROACH 25% AWAY FROM THE COAST BUT WINDS ARE EXPECTED TO REMAIN RELATIVELY LIGHT THROUGH THE PERIOD. A CHANCE FOR WETTING RAINS WILL ARRIVE LATER WEDNESDAY ACROSS THE SOUTH...AND BY THURSDAY FOR NORTHERN ZONES. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ LEGRO/JC/MLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
634 AM EDT MON MAY 6 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH WEDNESDAY MORNING. LOW PRESSURE APPROACHING FROM THE SOUTH WILL BRING SCATTERED SHOWERS TO THE AREA LATE WEDNESDAY THROUGH FRIDAY. ANOTHER LOW PRESSURE SYSTEM MOVES IN FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... UPDATE...AS EXPECTED STRATUS IS ON THE DOORSTEP OF SRN NH ATTM. APPEARS AS THOUGH IT WILL NOT MAKE IT MUCH FARTHER N...HOWEVER VALLEY FOG IS PREVALENT ALONG THE COAST. THIS IS COVERED WELL IN THE GRIDS...SO HAVE MAINLY USED CURRENT OBS TO ADJUST TEMPS FOR THE NEXT SEVERAL HRS. HAVE ALSO USED THE LATEST HRRR TO REFINE WIND FORECAST FOR THE SEA BREEZE. PREVIOUS DISCUSSION...PERSISTENCE CONTINUES TO RULE THE FORECAST IN THE NEAR TERM. HIGH PRES CENTERED INVOF NOVA SCOTIA REMAINS IN CONTROL OF THE REGION. BEING CLOSER TO THE RIDGE AXIS...THE COASTAL AREAS ARE SEEING SOME OF THE BEST RADIATIONAL COOLING AS A RESULT. HAVE LEANED ON BIAS CORRECT MOS FOR MIN TEMPS...SEEING AS THIS STRETCH OF WX HAVE PROVIDED SUFFICIENT DATA AND SIMILAR CONDS. KEEPING AN EYE ON COASTAL STRATUS OVER SRN NEW ENGLAND EDGING NWD. TRACKING ITS CURRENT SPEED...IT WOULD ARRIVE OVER SRN NH AND SWRN ME NEAR 10 TO 12Z. HAVE SOME HINTS OF IT IN THE GRIDS...BUT NOT CONFIDENT IT TOTALLY MAKES IT TONIGHT. WILL HAVE TO WATCH MORE FOR PATCHY FOG IN THE LOW LYING AREAS AS TEMPS BOTTOM OUT. EXPECTED ANOTHER NICE DAY TODAY...AS TEMPS WARM QUICKLY IN DRY CONDS. HIGHS WILL CLIMB WELL INTO THE 70S INLAND...WITH SEA BREEZE/SLY FLOW KEEPING THE COAST CLOSER TO 60. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS RIDGE AXIS CONTINUES TO SLIDE EWD...MORE AND MORE SLY FLOW WILL HELP TRANSPORT LLVL MOISTURE NWD. NAM IS NOT AS BULLISH AS ECMWF/GFS/CMC...BUT GIVEN THE GRADUAL NWD DISPLACEMENT EACH NIGHT EXPECT THAT IT SHOULD REACH THE COAST TONIGHT. INLAND AREAS WILL REMAIN UNDER CLEAR SKIES. STRATUS COULD STIFLE EARLY WARMING ALONG THE COAST TUE...BUT EXPECT ANOTHER PLEASANT DAY WITH HIGHS IN THE 60S ALONG THE COAST AND 70S TO NEAR 80 INLAND. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... EXTREMELY DRY PATTERN FOR THIS TIME OF THE YEAR WILL GRADUALLY BECOME MORE SEASONAL AS WE HEAD INTO THE EXTENDED PORTION OF THE FORECAST. SLOW MOVING...CUTOFF...UPPER LEVEL LOW WILL SLOWLY MOVE NORTHEAST...WEAKENING AS IT APPROACHES NEW ENGLAND. THIS SYSTEM WILL ALLOW SCATTERED SHOWERS TO ENTER FAR SOUTHERN AREAS LATE WEDNESDAY...BEFORE THE LIGHT PCPN SPREADS NORTH. ALL MODELS ARE RELATIVELY SIMILAR IN THE POSITIONING OF THE SFC LOW AND MOISTURE COMING IN OFF THE BRINK DURING THE MID TO LATE PORTION OF THE WORK WEEK. AHEAD OF THIS PCPN...LOW CLOUDS WILL MOVE IN OFF THE GULF OF MAINE. THIS MOISTURE WILL END OUR PERIOD OF OUR LARGE DIURNAL RANGES FROM THE DAYTIME MAXES TO THE OVERNIGHT LOWS. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... SHORT TERM...LOW CHANCE THAT SOME COASTAL STRATUS ARRIVES ACROSS SRN NH AND SWRN ME NEAR DAYBREAK THIS MORNING. OTHERWISE VFR CONDS TO PREVAIL UNTIL AFTER 00Z TUE. IFR CONDS ARE EXPECTED FOR COASTAL TERMINALS AS CIGS AND POSSIBLY VSBYS DECREASE IN STRATUS. LONG TERM... MARINE FOG LOOKS LIKELY TUESDAY AND WEDNESDAY MORNINGS RESULTING IN SOME AREAS OF MVFR OR LOWER. SCATTERED SHOWERS ENTER THE REGION FROM SOUTH TO NORTH WEDNESDAY NIGHT THROUGH THE END OF THE WORK WEEK. && .MARINE... SHORT TERM...LONG PERIOD SWELL AROUND 5 FT WILL CONTINUE EARLY THIS MORNING. GIVEN LACK OF STEEPNESS TO THE SEAS...NO SCA IS EXPECTED. WINDS WILL REMAIN BLO 25 KT. LONG TERM... MARINE FOG IS LIKELY TUESDAY AND WEDNESDAY MORNINGS WITH POOR VISIBILITY. WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA. SEAS MAY BRIEFLY REACH 5 FT THURSDAY. && .FIRE WEATHER... HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER WITH NO RAIN EXPECTED THROUGH TUESDAY. DAYTIME RELATIVE HUMIDITY WILL APPROACH 25% AWAY FROM THE COAST BUT WINDS ARE EXPECTED TO REMAIN RELATIVELY LIGHT THROUGH THE PERIOD. A CHANCE FOR WETTING RAINS WILL ARRIVE LATER WEDNESDAY ACROSS THE SOUTH...AND BY THURSDAY FOR NORTHERN ZONES. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ LEGRO/JC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 PM EDT MON MAY 6 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 405 PM EDT MON MAY 6 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BLOCKY FLOW ACROSS THE CONUS TO THE S OF NEARLY ZONAL FLOW ACROSS CNTRL CANADA. A NARROW RIDGE EXTENDS FROM SRN BRITISH COLUMBIA E ACROSS THE UPPER GREAT LAKES TO NEW ENGLAND. FARTHER S...CLOSED MID LEVEL LOWS WERE LOCATED JUST OFF THE CA COAST...OVER SD AND OVER THE SE CONUS. WITH THE UPPER GREAT LAKES UNDER THE RIDGE...IT`S BEEN A PLEASANT EARLY MAY DAY ACROSS UPPER MI AS DEEP DRY COLUMN IS ALLOWING FOR ABUNDANT SUNSHINE. LAKE BREEZES HAVE DEVELOPED ACROSS THE BOARD. WHILE IT`S CHILLY ALONG LAKE SUPERIOR WITH TEMPS IN THE 40S...SIGNIFICANT COOLING HAS YET TO OCCUR ALONG MOST OF THE LAKE MI SHORELINE. INLAND...TEMPS HAVE SOARED THRU THE 60S TO AS HIGH AS THE LOW/MID 70S. LAST BIT OF LINGERING FOG OVER WRN LAKE SUPERIOR BTWN THE APOSTLE ISLANDS AND UPPER MI HAS JUST ABOUT DISSIPATED AS OF 1930Z. WITH LITTLE CHANGE IN THE AIR MASS THRU TUE...FCST FOR TONIGHT/TUE WILL BE SIMILAR TO LAST NIGHT/TODAY. LIGHT/CALM WIND AND CLEAR SKIES WILL LEAD TO GOOD RADIATIONAL COOLING CONDITIONS TONIGHT. HOWEVER... PRECIPITABLE WATER DOES RISE SOME COMPARED TO LAST NIGHT OVER THE W HALF OR SO (UP TOWARD NORMAL FROM 60PCT OF NORMAL LAST NIGHT). ALONG WITH AIR MASS MODERATION TODAY...MINS TONIGHT SHOULD BE SEVERAL DEGREES HIGHER THAN LAST NIGHT. COLUMN REMAINS DRIER OVER THE E...SO MINS THERE WILL PROBABLY BE WITHIN A COUPLE OF DEGREES OF LAST NIGHTS MINS. OVERALL...EXPECT MIN TEMPS TONIGHT IN THE 30S. MIGHT SEE SOME PATCHY GROUND FOG OVER THE INTERIOR W LATE TONIGHT. 850MB TEMPS TUE ARE NEARLY THE SAME AS TODAY. WITH ABUNDANT SUNSHINE AGAIN (SHOULD BE SOME CU OVER THE W)...MAX TEMPS WILL BE SIMILAR TO WHAT IS BEING OBSERVED THIS AFTN. SFC HIGH PRES RIDGED ACROSS THE UPPER LAKES WILL LEAD TO ANOTHER DAY OF LAKE BREEZES. HOWEVER...WITH HIGH CENTER SETTING UP A LITTLE FARTHER E...LIGHT SOUTHERLY GRADIENT FLOW SHOULD LEAD TO A LESS AGGRESSIVE INLAND PUSH OF THE LAKE SUPERIOR LAKE BREEZE...AND COOLING SHOULD BE A LITTLE STRONGER ALONG LAKE MI SAT AFTN COMPARED TO TODAY. TAKING INTO ACCOUNT MIXING DEPTH... DWPTS SHOULD TANK IN SOME INLAND AREAS WITH RH BOTTOMING OUT AS LOW AS AROUND 20PCT. IN GENERAL...RH SHOULD BE IN 20S INLAND. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 436 PM EDT MON MAY 6 2013 THE 500MB RIDGE THAT HAS BEEN SET UP ACROSS UPPER MICHIGAN WILL BE EXITING EASTWARD TUESDAY NIGHT...WITH AN OPEN WAVE/TROUGH EXTENDING FROM NORTHERN CANADA THROUGH THE DAKOTAS SHIFTING TOWARD MINNESOTA AND ONTARIO. WEAK SSW WINDS FLOW WILL SLOWLY BRING BACK INCREASED MOISTURE THROUGH THE DAY WEDNESDAY...WITH PW VALUES JUMPING AT OR ABOVE 1IN BY MID AFTERNOON OVER THE WESTERN THIRD OF THE CWA /175 PERCENT OR NORMAL OR MORE/. THE MAIN RESULT WILL BE INCREASED CLOUD COVER. A WEAKENING SFC TROUGH WILL SINK FROM NW LAKE SUPERIOR AT DAYBREAK WEDNESDAY. FCST MODELS ARE VERY CONSISTENT WITH THE TRACK/TIMING OF THE TROUGH AS OF THE 12Z RUNS. EXPECT THE TROUGH TO PUSH ACROSS CENTRAL LAKE SUPERIOR BY 18Z...AND THEN SINK ACROSS UPPER MI WEDNESDAY AFTERNOON...TO JUST S OF THE CWA BY 06Z THURSDAY. A FEW SHOWERS WILL BE POSSIBLE WEDNESDAY NIGHT THROUGH THURSDAY...WITH TOTAL QPF AROUND A TENTH OF AN INCH OR LESS. STRONG HIGH PRESSURE ACROSS MOST OF CENTRAL CANADA WILL SLOWLY SINK IN BEHIND THE TROUGH...BRINGING WITH IT A RETURN OF DRIER AND COLDER AIR. 850MB TEMPS ARE ANTICIPATED TO FALL FROM AROUND 9C WEDNESDAY AFTERNOON TO AROUND 4C BY FRIDAY AFTERNOON. LOOKING MORE AT THE FIRE FRONT...THE CENTRAL AND EASTERN UPPER MICHIGAN WILL CONTINUE TO BE THE DRIEST THROUGH AT LEAST FRIDAY NIGHT. WINDS MAY BECOME A CONCERN ON SATURDAY...PICKING UP OUT OF A NW DIRECTION THROUGHOUT THE DAY...BEHIND A STRONGER COLD FRONT WITH A REINFORCING SHORTWAVE. A 30-35KT LLJ CORE AROUND 800BM THROUGH MUCH OF THE DAY SATURDAY OVER THE WEST...RESULTING IN 20-25KT GUSTS SATURDAY THROUGH MUCH OF SUNDAY. ON A POSITIVE NOTE...A TENTH TO QUARTER OF AN INCH IS OF RAIN IS FORECAST...AND MUCH COLDER AIR WILL BE SINKING IN. 850MB TEMPS WILL COOL SIGNIFICANTLY...WITH THE 12Z ECMWF COMING IN WITH -8 TO -10C READINGS FROM 06-18Z SUNDAY. WITH A DEEPER AND SLOWER SYSTEM OVERALL...A FEW FLURRIES WILL BE POSSIBLE FROM SATURDAY THROUGH SUNDAY. THE GOOD NEWS FOR THOSE WHO WOULD RATHER NOT SEE ANOTHER SNOWFLAKE UNTIL THE FALL...MOST OF THE MOISTURE WILL BE OUT OF THE AREA BEFORE THE COLD AIR ARRIVES. DO NOT EXPECT ANY TRAVEL CONCERNS OR PLOWING NEEDED...GIVEN THE STRENGTH OF THE SUN THIS TIME OF YEAR...AND THE WARM ROADWAYS. GRASSY SURFACES WILL REALLY SEE THE ONLY CHANCE OF ANY DUSTING OF SNOW. AFTER A COOL WEEKEND WITH HIGHS IN THE 40S TO AROUND 50...TEMPS WILL WARM UP AGAIN TO NEAR NORMAL READINGS BY MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 135 PM EDT MON MAY 6 2013 EXPECT VFR CONDITIONS/LIGHT WINDS AT KIWD/KCMX/KSAW THIS TAF PERIOD WITH DRY HIGH PRES DOMINATING. HOWEVER...THERE MAY BE ONE EXCEPTION. SOME FOG (MVFR VIS) MAY DEVELOP AT KIWD LATE TONIGHT. NOT OUT OF THE QUESTION THAT BRIEF IFR OR EVEN LIFR COULD OCCUR AS WELL. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 405 PM EDT MON MAY 6 2013 QUIET WEATHER WILL CONTINUE OVER THE UPPER GREAT LAKES FOR THE NEXT COUPLE OF DAYS. WITH HIGH PRES RIDGE REMAINING OVER THE AREA...WINDS WILL LIKELY REMAIN UNDER 15KT THRU WED AFTN. THEN...A COLD FRONT DROPPING SOUTHEAST ACROSS THE UPPER GREAT LAKES WEDNESDAY NIGHT WILL BRING A WIND SHIFT AND STRONGER WINDS INTO THE 15-25KT RANGE FOR A TIME LATER WED NIGHT INTO THU. WINDS WILL DIMINISH HEADING INTO FRI AS A HIGH PRES SYSTEM MOVES ACROSS NRN ONTARIO. A STRONG COLD FRONT PASSING FRI NIGHT/SAT MORNING WILL BRING ANOTHER ROUND OF 15-25KT WINDS FOR SAT. && .HYDROLOGY... ISSUED AT 436 PM EDT MON MAY 6 2013 HYDROLOGY CONCERNS CONTINUE...BUT ARE SLOWLY DIMINISHING AT ALL SITES EXCEPT FOR LAKE LINDEN ON THE TRAP ROCK RIVER WHICH HAS BEEN SHOWING ITS USUAL DIURNAL INCREASE AS A RESULT OF THE SIGNIFICANT SNOW PACK STILL MELTING ACROSS THE KEWEENAW PENINSULA. THE LATEST SNOW DEPTH OBSERVATIONS /FROM EARLIER THIS MORNING AROUND 8AM/ STILL HAVE AROUND 3IN AT IRONWOOD...AND 7IN AT ATLANTIC MINE. A FEW POCKETS OF HIGHER AMOUNTS ARE LIKELY ACROSS THE KEWEENAW. THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE OF DAYS. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND ADVISORIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...ROLFSON MARINE...ROLFSON HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EDT MON MAY 6 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 405 PM EDT MON MAY 6 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BLOCKY FLOW ACROSS THE CONUS TO THE S OF NEARLY ZONAL FLOW ACROSS CNTRL CANADA. A NARROW RIDGE EXTENDS FROM SRN BRITISH COLUMBIA E ACROSS THE UPPER GREAT LAKES TO NEW ENGLAND. FARTHER S...CLOSED MID LEVEL LOWS WERE LOCATED JUST OFF THE CA COAST...OVER SD AND OVER THE SE CONUS. WITH THE UPPER GREAT LAKES UNDER THE RIDGE...IT`S BEEN A PLEASANT EARLY MAY DAY ACROSS UPPER MI AS DEEP DRY COLUMN IS ALLOWING FOR ABUNDANT SUNSHINE. LAKE BREEZES HAVE DEVELOPED ACROSS THE BOARD. WHILE IT`S CHILLY ALONG LAKE SUPERIOR WITH TEMPS IN THE 40S...SIGNIFICANT COOLING HAS YET TO OCCUR ALONG MOST OF THE LAKE MI SHORELINE. INLAND...TEMPS HAVE SOARED THRU THE 60S TO AS HIGH AS THE LOW/MID 70S. LAST BIT OF LINGERING FOG OVER WRN LAKE SUPERIOR BTWN THE APOSTLE ISLANDS AND UPPER MI HAS JUST ABOUT DISSIPATED AS OF 1930Z. WITH LITTLE CHANGE IN THE AIR MASS THRU TUE...FCST FOR TONIGHT/TUE WILL BE SIMILAR TO LAST NIGHT/TODAY. LIGHT/CALM WIND AND CLEAR SKIES WILL LEAD TO GOOD RADIATIONAL COOLING CONDITIONS TONIGHT. HOWEVER... PRECIPITABLE WATER DOES RISE SOME COMPARED TO LAST NIGHT OVER THE W HALF OR SO (UP TOWARD NORMAL FROM 60PCT OF NORMAL LAST NIGHT). ALONG WITH AIR MASS MODERATION TODAY...MINS TONIGHT SHOULD BE SEVERAL DEGREES HIGHER THAN LAST NIGHT. COLUMN REMAINS DRIER OVER THE E...SO MINS THERE WILL PROBABLY BE WITHIN A COUPLE OF DEGREES OF LAST NIGHTS MINS. OVERALL...EXPECT MIN TEMPS TONIGHT IN THE 30S. MIGHT SEE SOME PATCHY GROUND FOG OVER THE INTERIOR W LATE TONIGHT. 850MB TEMPS TUE ARE NEARLY THE SAME AS TODAY. WITH ABUNDANT SUNSHINE AGAIN (SHOULD BE SOME CU OVER THE W)...MAX TEMPS WILL BE SIMILAR TO WHAT IS BEING OBSERVED THIS AFTN. SFC HIGH PRES RIDGED ACROSS THE UPPER LAKES WILL LEAD TO ANOTHER DAY OF LAKE BREEZES. HOWEVER...WITH HIGH CENTER SETTING UP A LITTLE FARTHER E...LIGHT SOUTHERLY GRADIENT FLOW SHOULD LEAD TO A LESS AGGRESSIVE INLAND PUSH OF THE LAKE SUPERIOR LAKE BREEZE...AND COOLING SHOULD BE A LITTLE STRONGER ALONG LAKE MI SAT AFTN COMPARED TO TODAY. TAKING INTO ACCOUNT MIXING DEPTH... DWPTS SHOULD TANK IN SOME INLAND AREAS WITH RH BOTTOMING OUT AS LOW AS AROUND 20PCT. IN GENERAL...RH SHOULD BE IN 20S INLAND. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 355 AM EDT MON MAY 6 2013 THE QUIET WEATHER WILL CONTINUE FOR THE START OF THE LONG TERM PERIOD...AS DUAL CUTOFF LOWS /ONE OVER THE SE CONUS AND THE OTHER NEAR CALIFORNIA/ KEEP THE UNSETTLED WEATHER OVER THE SOUTHERN HALF OF THE CONUS. MEANWHILE...THE NORTHERN STREAM JET RUNNING WEST-EAST ACROSS CENTRAL CANADA WILL KEEP THE COLDER AIR LOCKED UP TO THE NORTH FOR THE TIME BEING. AT THE SURFACE...HIGH PRESSURE WILL STILL BE OVER THE UPPER GREAT LAKES FOR TUESDAY INTO WEDNESDAY MORNING AND PRODUCE MOSTLY CLEAR SKIES ACROSS THE AREA. THERE ARE STILL HINTS OF SOME HIGH-BASED DIURNAL CU OVER THE WESTERN CWA ON TUESDAY AFTERNOON...BUT NOT EXPECTING MUCH MORE THAN THAT. WITH THE DEEP MIXING...EXPECT ANOTHER ABOVE NORMAL DAY OVER THE CWA...WITH HIGHS IN THE 70S EXCEPT WHERE LAKE BREEZES KEEP TEMPERATURES COOLER NEAR THE GREAT LAKES. TEMPERATURES SHOULD BE SIMILAR ON WEDNESDAY...ALTHOUGH THE INCREASING CLOUDS AND POTENTIAL PRECIPITATION MAY KEEP THE WEST HALF A LITTLE COOLER. DID TREND DEWPOINTS DOWN FOR TUESDAY AFTERNOON OVER THE CENTRAL AND EAST BASED OFF THE LAST COUPLE OF DAYS. WITH THE GOOD MIXING THOSE DAYS...RH VALUES FELL INTO THE UPPER TEENS AND 20S AWAY FROM THE LAKE INFLUENCES AND WOULD EXPECT THE SAME FOR TUESDAY. THAT IDEA MATCHES MIXED LAYER DEWPOINTS FROM THE MODELS AND TRENDED THAT DIRECTION. THE FIRST CHANCE OF PRECIPITATION FOR THE LONG TERM PERIOD WILL COME LATE WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. THIS IS DUE TO A SHORTWAVE IN THE NORTHERN STREAM WAVE PRODUCING A LOW THAT SHIFTS EAST INTO QUEBEC ON WEDNESDAY. A TRAILING COLD FRONT WILL THEN TRY TO DIVE SOUTHEAST ACROSS THE UPPER GREAT LAKES ON WEDNESDAY NIGHT INTO THURSDAY MORNING. THE MAIN FORECAST IMPACT IS WHAT WILL HAPPEN WITH THE MOISTURE AND SMALL CLOSED PIECE OF ENERGY THAT TRIES TO DRIFT NORTHEAST AND INTERACT WITH THE NORTHERN STREAM. THE MODELS CONTINUE TO DIFFER WITH THIS INTERACTION AND PROVIDES UNCERTAINTY IN THE QPF AMOUNTS. WILL CONTINUE TO GO WITH A GENERAL CONSENSUS POP/QPF DURING THIS PERIOD AND HAVE SLIGHTS OR LOW CHANCE POPS FOR LATE WEDNESDAY AFTERNOON INTO THURSDAY MORNING. WITH THE COLD FRONT MOVING SOUTHEAST OF THE AREA...EXPECT DRIER AIR TO DIMINISHING PRECIPITATION CHANCES BY THURSDAY AFTERNOON AS A CANADIAN HIGH PRESSURE RIDGE DROPS OVER THE AREA. THIS RIDGE WILL REMAIN OVER THE AREA FOR FRIDAY AND LEAD TO DRY BUT COOLER WEATHER WITH HIGHS IN THE 50S. A MUCH STRONGER NORTHERN STREAM WAVE WILL BE DIVING SOUTHEAST TOWARDS THE UPPER GREAT LAKES ON SATURDAY AND BRING MUCH COOLER WEATHER FOR THE WEEKEND. WILL CONTINUE THE CHANCE POPS WITH THIS SYSTEM...BUT WITH LITTLE MOISTURE RETURN AHEAD OF THE WAVE...QPF AMOUNTS WILL BE ON THE LIGHT SIDE. PRECIPITATION SHOULD FALL AS RAIN...AS THE COLDEST AIR DOESN/T ARRIVE UNTIL AFTER MOST OF THE DEEP MOISTURE EXITS. WITH THE BETTER CONSISTENCY IN THE MODELS FOR THIS WAVE...HAVE TRENDED HIGHS DOWN INTO THE UPPER 40S OR LOWER 50S FOR SATURDAY ALTHOUGH THERE IS SOME CONCERNS THE EAST COULD SEE WARMER HIGHS AROUND DAYBREAK AND THEN FALLING THROUGH THE DAY. THE TROUGH WILL QUICKLY SHIFT EAST TO THE NEW ENGLAND STATES ON SUNDAY AND ALLOW RETURN FLOW TO DEVELOP. SUNDAY SHOULD BE DRY BUT COOL BUT THEN WARMING IS EXPECTED FOR THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 135 PM EDT MON MAY 6 2013 EXPECT VFR CONDITIONS/LIGHT WINDS AT KIWD/KCMX/KSAW THIS TAF PERIOD WITH DRY HIGH PRES DOMINATING. HOWEVER...THERE MAY BE ONE EXCEPTION. SOME FOG (MVFR VIS) MAY DEVELOP AT KIWD LATE TONIGHT. NOT OUT OF THE QUESTION THAT BRIEF IFR OR EVEN LIFR COULD OCCUR AS WELL. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 405 PM EDT MON MAY 6 2013 QUIET WEATHER WILL CONTINUE OVER THE UPPER GREAT LAKES FOR THE NEXT COUPLE OF DAYS. WITH HIGH PRES RIDGE REMAINING OVER THE AREA...WINDS WILL LIKELY REMAIN UNDER 15KT THRU WED AFTN. THEN...A COLD FRONT DROPPING SOUTHEAST ACROSS THE UPPER GREAT LAKES WEDNESDAY NIGHT WILL BRING A WIND SHIFT AND STRONGER WINDS INTO THE 15-25KT RANGE FOR A TIME LATER WED NIGHT INTO THU. WINDS WILL DIMINISH HEADING INTO FRI AS A HIGH PRES SYSTEM MOVES ACROSS NRN ONTARIO. A STRONG COLD FRONT PASSING FRI NIGHT/SAT MORNING WILL BRING ANOTHER ROUND OF 15-25KT WINDS FOR SAT. && .HYDROLOGY... ISSUED AT 355 AM EDT MON MAY 6 2013 HYDROLOGY CONCERNS WILL REMAIN OVER THE COMING DAYS...UNTIL THE REMAINING SNOW PACK MELTS OVER THE NORTHWESTERN THIRD OF UPPER MICHIGAN. VISIBLE SATELLITE AND MODIS IMAGERY YESTERDAY STILL SHOWS SNOW REMAINING IN THE HIGHER TERRAIN LOCATIONS OF THE HURON MOUNTAINS AND THE KEWEENAW PENINSULA. DID SEE RISES AT SOME OF THE SITES OVER THE WEST /ESPECIALLY TRRM4/ WITH THE WARMER TEMPERATURES YESTERDAY AND WOULD EXPECT THAT TO CONTINUE UNTIL THE REMAINING SNOW IS GONE. AT THIS TIME...WOULD THINK TRRM4 WILL BE THE MAIN THREAT FOR REACHING ADVISORY OR FLOOD STAGE FROM THIS ADDITIONAL MELT. OTHERWISE...THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE OF DAYS. THE REST RIVER LEVELS ARE ON THE DOWNWARD TREND AND WILL LIKELY CONTINUE THIS WEEK. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND ADVISORIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...ROLFSON MARINE...ROLFSON HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
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
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 AM EDT MON MAY 6 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM EDT MON MAY 6 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG STRETCHING FM THE NE CONUS W INTO THE UPR GRT LKS TO THE N OF CUTOFF LO OVER THE SE CONUS. VERY DRY AIRMASS SHOWN ON THE 00Z GRB/APX RAOBS... WHICH SHOW A PWAT ARND 0.25 INCH OR 50 PCT OF NORMAL...DOMINATES THE CWA. SO SKIES ARE MOCLR EXCEPT FOR SOME HI CLDS. SFC HI PRES IS CENTERED NEAR WRN LK SUP...AND SOME LO CLDS/FOG ARE APRNT OVER WRN LK SUP NEAR THE W COAST OF UPR MI CLOSER TO MOISTER AIRMASS SHOWN ON THE 00Z INL RAOB. DESPITE THE LGT WINDS AND TEMPS FALLING TOWARD 30 CLOSER TO THIS MSTR...NO FOG HAS YET FORMED OVER WRN UPR MI AS OF FCST ISSUANCE. TODAY/TNGT...UPR RDG IS FCST TO REMAIN DOMINANT THRU THIS TIME WITH SFC HI PRES REMAINING NEARLY STNRY OVER LK SUP. WITH DRY AIRMASS ALSO LINGERING...THE ONLY MAJOR CONCERNS ARE TEMPS...THE POTENTIAL FOR FOG THIS MRNG/TNGT...AND POTENTIAL LOW RH THIS AFTN...ESPECIALLY OVER THE E HALF CLOSER TO CORE OF DRY AIRMASS. BEST CHC FOR FOG EARLY THIS MRNG WL BE OVER THE INTERIOR W...CLOSER TO AREA OF FOG/ LO CLD STRETCHING FM THE W SHORE OF THE KEWEENAW DOWN TOWARD IWD/ASX. ANY FOG THAT DOES DVLP SHOULD BURN OFF FAIRLY QUICKLY WITH THE ONSET OF DAYTIME HEATING. WITH H85 TEMPS TOPPING OUT AT 9-10C AGAIN TODAY...EXPECT MAX TEMPS TO BE SIMILAR TO WHAT OCCURRED YDAY AT MOST LOCATIONS. THE ONLY EXCEPTION WL BE OVER THE NCENTRAL AND W NEAR LK SUP...WHERE A WEAKER SYNOPTIC FLOW THAN YDAY WL LIMIT THE INLAND EXTENT OF LK MODERATION. SO ALTHOUGH TEMPS NEAR THE SHORE IN THIS AREA MIGHT HAVE A HARD TIME TOPPING 50...MUCH OF THE NCENTRAL AND W WL BE WARMER THAN YDAY. MIXING TO H8-85 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS UP TO 70-75 OVER THE INTERIOR AWAY FM LOCAL LK BREEZE MODERATION. PREFER THE DRIER LOOK TO THE NAM FCST SDNGS GIVEN BONE DRY GRB/APX RAOBS. DEEP MIXING ON THESE FCST SDNGS SUG DEWPTS WL MIX OUT AS LO AS 30 TO 35 OVER THE INTERIOR DURING PEAK HEATING...LOWERING MIN RH AS LO AS 20-25 PCT. THE BEST CHC FOR THE LOWER DEWPTS WL BE OVER THE E WHERE THE GROUND IS QUITE A BIT DRIER THAN OVER THE W/CENTRAL. FORTUNATELY WINDS WL BE LGT...SO NO FIRE WX HEADLINES ARE NECESSARY. FOR TNGT...WITH LGT WINDS AND DRY AIRMASS LINGERING...EXPECT A HEALTHY DROP OF TEMP. PREFER TO TEND TOWARD THE LOWER END OF GUIDANCE FOR MIN TEMPS...BUT MODERATING AIRMASS SUGGESTS TEMPS TNGT WL NOT BE AS CHILLY AS EARLY THIS MRNG. SINCE FOG HAS BEEN SLOW TO FORM THIS MRNG AND THE LLVLS TNGT WL LIKELY TO BE AS DRY...OPTED TO MAINTAIN FCST FOR PATCHY FOG ONLY OVER THE INTERIOR W WHERE TEMPS AT SOME OF THE FAVORED COOL SPOTS SEE MIN TEMPS FALLING TOWARD 33. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 355 AM EDT MON MAY 6 2013 THE QUIET WEATHER WILL CONTINUE FOR THE START OF THE LONG TERM PERIOD...AS DUAL CUTOFF LOWS /ONE OVER THE SE CONUS AND THE OTHER NEAR CALIFORNIA/ KEEP THE UNSETTLED WEATHER OVER THE SOUTHERN HALF OF THE CONUS. MEANWHILE...THE NORTHERN STREAM JET RUNNING WEST-EAST ACROSS CENTRAL CANADA WILL KEEP THE COLDER AIR LOCKED UP TO THE NORTH FOR THE TIME BEING. AT THE SURFACE...HIGH PRESSURE WILL STILL BE OVER THE UPPER GREAT LAKES FOR TUESDAY INTO WEDNESDAY MORNING AND PRODUCE MOSTLY CLEAR SKIES ACROSS THE AREA. THERE ARE STILL HINTS OF SOME HIGH-BASED DIURNAL CU OVER THE WESTERN CWA ON TUESDAY AFTERNOON...BUT NOT EXPECTING MUCH MORE THAN THAT. WITH THE DEEP MIXING...EXPECT ANOTHER ABOVE NORMAL DAY OVER THE CWA...WITH HIGHS IN THE 70S EXCEPT WHERE LAKE BREEZES KEEP TEMPERATURES COOLER NEAR THE GREAT LAKES. TEMPERATURES SHOULD BE SIMILAR ON WEDNESDAY...ALTHOUGH THE INCREASING CLOUDS AND POTENTIAL PRECIPITATION MAY KEEP THE WEST HALF A LITTLE COOLER. DID TREND DEWPOINTS DOWN FOR TUESDAY AFTERNOON OVER THE CENTRAL AND EAST BASED OFF THE LAST COUPLE OF DAYS. WITH THE GOOD MIXING THOSE DAYS...RH VALUES FELL INTO THE UPPER TEENS AND 20S AWAY FROM THE LAKE INFLUENCES AND WOULD EXPECT THE SAME FOR TUESDAY. THAT IDEA MATCHES MIXED LAYER DEWPOINTS FROM THE MODELS AND TRENDED THAT DIRECTION. THE FIRST CHANCE OF PRECIPITATION FOR THE LONG TERM PERIOD WILL COME LATE WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. THIS IS DUE TO A SHORTWAVE IN THE NORTHERN STREAM WAVE PRODUCING A LOW THAT SHIFTS EAST INTO QUEBEC ON WEDNESDAY. A TRAILING COLD FRONT WILL THEN TRY TO DIVE SOUTHEAST ACROSS THE UPPER GREAT LAKES ON WEDNESDAY NIGHT INTO THURSDAY MORNING. THE MAIN FORECAST IMPACT IS WHAT WILL HAPPEN WITH THE MOISTURE AND SMALL CLOSED PIECE OF ENERGY THAT TRIES TO DRIFT NORTHEAST AND INTERACT WITH THE NORTHERN STREAM. THE MODELS CONTINUE TO DIFFER WITH THIS INTERACTION AND PROVIDES UNCERTAINTY IN THE QPF AMOUNTS. WILL CONTINUE TO GO WITH A GENERAL CONSENSUS POP/QPF DURING THIS PERIOD AND HAVE SLIGHTS OR LOW CHANCE POPS FOR LATE WEDNESDAY AFTERNOON INTO THURSDAY MORNING. WITH THE COLD FRONT MOVING SOUTHEAST OF THE AREA...EXPECT DRIER AIR TO DIMINISHING PRECIPITATION CHANCES BY THURSDAY AFTERNOON AS A CANADIAN HIGH PRESSURE RIDGE DROPS OVER THE AREA. THIS RIDGE WILL REMAIN OVER THE AREA FOR FRIDAY AND LEAD TO DRY BUT COOLER WEATHER WITH HIGHS IN THE 50S. A MUCH STRONGER NORTHERN STREAM WAVE WILL BE DIVING SOUTHEAST TOWARDS THE UPPER GREAT LAKES ON SATURDAY AND BRING MUCH COOLER WEATHER FOR THE WEEKEND. WILL CONTINUE THE CHANCE POPS WITH THIS SYSTEM...BUT WITH LITTLE MOISTURE RETURN AHEAD OF THE WAVE...QPF AMOUNTS WILL BE ON THE LIGHT SIDE. PRECIPITATION SHOULD FALL AS RAIN...AS THE COLDEST AIR DOESN/T ARRIVE UNTIL AFTER MOST OF THE DEEP MOISTURE EXITS. WITH THE BETTER CONSISTENCY IN THE MODELS FOR THIS WAVE...HAVE TRENDED HIGHS DOWN INTO THE UPPER 40S OR LOWER 50S FOR SATURDAY ALTHOUGH THERE IS SOME CONCERNS THE EAST COULD SEE WARMER HIGHS AROUND DAYBREAK AND THEN FALLING THROUGH THE DAY. THE TROUGH WILL QUICKLY SHIFT EAST TO THE NEW ENGLAND STATES ON SUNDAY AND ALLOW RETURN FLOW TO DEVELOP. SUNDAY SHOULD BE DRY BUT COOL BUT THEN WARMING IS EXPECTED FOR THE FIRST PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 728 AM EDT MON MAY 6 2013 EXPECT VFR CONDITIONS/LIGHT WINDS THIS TAF PERIOD WITH DRY HI PRES DOMINATING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 355 AM EDT MON MAY 6 2013 A QUIET PERIOD OF WEATHER IS EXPECTED THROUGH THE PERIOD...WITH THE WINDS LIKELY STAYING BELOW 25KTS. HIGH PRESSURE THAT HAS SETUP OVER THE AREA WILL REMAIN THROUGH WEDNESDAY MORNING AND LEAD TO LIGHT WINDS. THEN...A COLD FRONT DROPPING SOUTHEAST ACROSS THE UPPER GREAT LAKES ON WEDNESDAY NIGHT WILL BRING A WIND SHIFT BUT ONLY 10-20KT WINDS. WEAK HIGH PRESSURE WILL MOVE OVER NORTHERN LAKE SUPERIOR FOR THURSDAY AFTERNOON INTO FRIDAY AND DIMINISH THE WINDS. && .HYDROLOGY... ISSUED AT 355 AM EDT MON MAY 6 2013 HYDROLOGY CONCERNS WILL REMAIN OVER THE COMING DAYS...UNTIL THE REMAINING SNOW PACK MELTS OVER THE NORTHWESTERN THIRD OF UPPER MICHIGAN. VISIBLE SATELLITE AND MODIS IMAGERY YESTERDAY STILL SHOWS SNOW REMAINING IN THE HIGHER TERRAIN LOCATIONS OF THE HURON MOUNTAINS AND THE KEWEENAW PENINSULA. DID SEE RISES AT SOME OF THE SITES OVER THE WEST /ESPECIALLY TRRM4/ WITH THE WARMER TEMPERATURES YESTERDAY AND WOULD EXPECT THAT TO CONTINUE UNTIL THE REMAINING SNOW IS GONE. AT THIS TIME...WOULD THINK TRRM4 WILL BE THE MAIN THREAT FOR REACHING ADVISORY OR FLOOD STAGE FROM THIS ADDITIONAL MELT. OTHERWISE...THE ONGOING FLOODING ON THE STURGEON RIVER AT ALSTON AND CHASSELL...THE MICHIGAMME RIVER AROUND WITCH LAKE...AND THE PAINT RIVER NEAR CRYSTAL FALLS WILL REMAIN A CONCERN FOR THE NEXT COUPLE OF DAYS. THE REST RIVER LEVELS ARE ON THE DOWNWARD TREND AND WILL LIKELY CONTINUE THIS WEEK. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND ADVISORIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...KC MARINE...SRF HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
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
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
256 PM MDT Mon May 6 2013 .DISCUSSION... Tonight through Wednesday...Fairly benign weather pattern will continue overnight. An upper ridge remains in place across central and northern Montana with associated subsidence providing cloud- free skies and mild temperatures. Circulation from an upper low offshore of the California coast is spreading moisture and instability across the inter-mountain region and into extreme southern and southwest Montana. Models indicate some CAPE is available over the area but HRRR analysis indicates moisture is lacking and very few thunderstorms are depicted through the early evening hours. The upper low begins moving east on Tuesday with showers and/or thunderstorms becoming a bit more numerous across the south and southwest during the afternoon. By Wednesday, the upper ridge gets suppressed to the south and northwest flow aloft sets up over the area. Enough moisture and instability will be present for isolated thunderstorms across the area. Temperatures will remain above seasonal averages. Emanuel Wednesday Night through Monday...Medium range models continue to indicate that unsettled weather will remain across the area through Saturday. An upper level ridge of high pressure from along the California coast into the Pacific Northwest and an upper level trough of low pressure over central/eastern Canada will combine to keep Montana under a moist and cyclonic northwesterly flow aloft. Weak disturbances in the flow will generally keep a chance of mainly afternoon and evening showers and thunderstorms over the area. Moisture being drawn north by an upper level low pressure area moving across the central Rockies Wednesday night through Thursday night will enhance this chance of measurable precipitation. However, the models seem to agree with this forecast cycle that a strong Canadian cold front will move south through the area on Friday. Have therefore increased the overall chance for showers/thunderstorms during this time and introduced breezy northerly winds in the wake of the front. For Saturday night into Sunday night, models are in better agreement with moving the upper level ridge will move east into Montana. Have mostly gone with dry conditions during this time, with only a slight chance of showers/thunderstorms in the mountains. As the ridge axis moves east of the area, models are indicating that a moist southwesterly flow aloft will combine with the passage of a Pacific cold front to bring a slightly better chance for showers/thunderstorms into Monday. Temperatures will generally be 5 to 10 degrees warmer than seasonal averages through Saturday, with a brief cooling back to near normal associated with the cold frontal passage on Friday. As the ridge builds into the area, temperatures will reach 10 to 15 degrees above normal for the latter portion of the weekend, but they will then cool about 5 to 10 degrees again on Monday with the passage of the second cold front. Coulston && .AVIATION... UPDATED 1830Z. VFR conditions expected across the region through 18Z Tuesday. High pressure will keep skies mostly clear and winds relatively light. Scattered moisture moving into far southwest Montana will cause scattered mid level clouds to develop and linger through around 06Z. Weak instability there may also cause an isolated shower or thunderstorm to develop as well. Any development will likely remain south of a KBZN-KBTM line. Expect a front to move into the region from the northwest around 18z tomorrow. Low ceilings and strong northerly winds will move in to KCTB after 18z before moving east-southeast through the day. && .PRELIMINARY POINT TEMPS/POPS... GTF 46 70 44 72 / 0 10 10 20 CTB 44 63 40 70 / 0 10 10 30 HLN 44 72 45 75 / 0 10 20 20 BZN 38 74 41 74 / 10 20 30 20 WEY 33 64 35 65 / 20 40 40 40 DLN 40 71 42 72 / 10 20 30 30 HVR 43 76 42 72 / 0 0 10 20 LWT 41 72 42 68 / 0 10 10 20 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1232 PM CDT MON MAY 6 2013 .SYNOPSIS... ISSUED AT 407 AM CDT MON MAY 6 2013 H5 ANALYSIS TONIGHT HAS THREE AREAS OF CLOSED LOW PRESSURE OVER THE CONUS. THE FIRST WAS OVER NRN ALABAMA...THE SECOND OFF THE NRN CA COAST AND A THIRD WEAKER SYSTEM WAS NOTED OVER CENTRAL SOUTH DAKOTA. AT THE SURFACE...WEAK HIGH PRESSURE WAS ANCHORED ACROSS NORTHERN NEBRASKA AND SOUTHERN SOUTH DAKOTA ATTM. RADIATIONAL COOLING UNDERNEATH THE HIGH...HAS LED TO SOME PATCHY FOG ACROSS NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE PAST HOUR...WITH VISBYS DOWN TO QUARTER MILE AT ONEILL. COMPARED TO 24 HOURS AGO...TEMPERATURES ARE MUCH WARMER ATTM WITH 3 AM CDT TEMPS RANGING FROM THE LOWER 30S IN THE NORTHEAST...TO THE LOWER 40S IN THE EASTERN PANHANDLE AND FAR SOUTHWESTERN NEBRASKA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 407 AM CDT MON MAY 6 2013 THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS ARE TEMPERATURES TODAY...AND THE THREAT FOR THUNDERSTORMS LATER TONIGHT. FOR THIS MORNING...OBSERVATIONS...SATELLITE IMAGERY AND HIGHWAY CAMS...CONTINUE TO INDICATE FOG ACROSS THE NORTHEASTERN CWA ATTM. THE LATEST VISIBILITY FOR ONEILL IS AROUND A QUARTER MILE. DECIDED TO HOIST A DENSE FOG ADVISORY TO COVER THIS THREAT THROUGH MID MORNING. ATTM...THE DENSE FOG THREAT APPEARS LOCALIZED WITH THE LOWEST VISBYS IN LOW LYING AREAS AND RIVER VALLEYS. BASED ON THE HRRR AND NAM12 BL RH FIELD...FOG SHOULD QUICKLY BURN OFF BY MID MORNING...WITH VISBYS IMPROVING QUICKLY AFTER 14Z. BASED ON THE HRRR...THE GREATEST THREAT FOR FOG SHOULD REMAIN ALONG AND EAST OF HIGHWAY 183. FOR THE REMAINDER OF TODAY...SRLY WINDS WILL INCREASE THIS AFTERNOON AS HIGH PRESSURE MOVES EAST OF THE AREA...AND LEE TROUGHING DEEPENS ACROSS EASTERN WYOMING AND EASTERN COLORADO. THE SRLY WINDS...WILL PUSH WARMER AIR AND INCREASED LOW LEVEL MOISTURE FROM THE SRN PLAINS INTO WESTERN AND NORTH CENTRAL NEBRASKA. THIS WILL RESULT IN HIGHS IN THE MID TO UPPER 60S THIS AFTERNOON...WHICH IS A SMALL DECREASE IN THE LOWER 70S IN THE INHERITED FCST. HIGHS WERE LOWERED AS I AM ANTICIPATING ADDITIONAL HIGH CLOUDINESS TO PUSH INTO THE FORECAST AREA LATER THIS AFTERNOON FROM THE SRN ROCKIES. THIS CLOUDINESS IS IN ADVANCE OF AN APPROACHING DISTURBANCE...WHICH WILL BEGIN TO IMPACT THE FORECAST AREA LATER TONIGHT. PRECIPITATION CHANCES WILL BEGIN TO INCREASE OVERNIGHT TONIGHT AS MID LEVEL WAA BEGINS TO LIFT INTO THE CENTRAL PLAINS IN ADVANCE OF AN APPROACHING UPPER LEVEL DISTURBANCE. ELEVATED INSTABILITY WILL INCREASE OVERNIGHT PER H800 CALCULATED LI`S RANGE FROM -1 TO -3 OVERNIGHT ACROSS CENTRAL AND NORTHERN NEBRASKA. ADDITIONAL FORCING FOR TSRAS WILL COME FROM THE DEVELOPMENT OF A 30 KT LLJET WHICH WILL EXTEND FROM WESTERN KS INTO SWRN NEBRASKA AFTER 06Z TONIGHT. COVERAGE OF TSRAS IS EXPECTED TO BE LIMITED THOUGH AS SURFACE DEW POINTS WILL ONLY BE IN THE LOWER TO MID 40S. ATTM...NO SEVERE THUNDERSTORMS ARE EXPECTED OVERNIGHT...AS LIFT AND AVAILABLE CAPE WILL BE LIMITED. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM CDT MON MAY 6 2013 BY TUESDAY MORNING THERE REALLY WON/T BE MUCH MOVEMENT IN THE PRIMARY UPPER LEVEL SYSTEMS ACROSS THE CONUS. THE UPPER LOW OVER THE SOUTHEAST PART OF THE COUNTRY WILL HAVE MOVED INTO THE CAROLINAS...WHILE THE SYSTEM OFF THE CALIFORNIA COAST WILL JUST BE MOVING ONSHORE BY 12Z TUESDAY. ALSO...THE WEAK UPPER LOW NOW OVER SOUTH DAKOTA WILL STAY STATIONARY THROUGH TUESDAY MORNING. MODEL SOLUTIONS HAVE STARTED TO BECOME MORE IN LINE FOR TUESDAY. THE SYSTEM OVER THE SOUTHEAST WILL SLOWLY LIFT NORTH ALONG THE EAST COAST THROUGH THE WEEK...WHILE THE CALIFORNIA LOW MOVES ONSHORE TUESDAY AND INTO THE GREAT BASIN TUESDAY NIGHT. MEANWHILE...THE WEAK UPPER LOW OVER THE DAKOTAS WILL STAY IN THE AREA THROUGH AT LEAST TUESDAY NIGHT AS THE NORTHERN STREAM STAYS WELL TO THE NORTH LEAVING NOTHING TO KICK IT OUT OF THE AREA. MEANWHILE...A WEAK SHORTWAVE TROUGH EJECTS OUT OF THE WEST COAST TROUGH AND PUSHES INTO THE CENTRAL PLAINS. PRECIPITATION CHANCES WILL INCREASE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT AHEAD OF THE SHORTWAVE TROUGH MOVING INTO THE AREA. MOISTURE WILL BE ON THE RISE ON TUESDAY AHEAD OF THIS FEATURE AS WELL...WITH THE MODELS BEING FAIRLY IN TUNE WITH EACH OTHER BRINGING IN 50 DEGREE DEWPOINTS INTO THE EASTERN PARTS OF THE FORECAST AREA. THIS MOISTURE ALONG WITH SOME COOLER TEMPERATURES ALOFT /THANKS TO THE UPPER LOW HANGING AROUND/ WILL CAUSE THE AIR TO BE UNSTABLE FOR THUNDERSTORMS MAINLY STARTING TUESDAY AFTERNOON. LOOKING FOR QUITE A BIT OF CLOUD COVER THROUGH THE DAY TUESDAY AND WITH AT LEAST PERIODIC SHOWERS AND THUNDERSTORMS...NOT EXPECTING TEMPERATURES TO BE TOO WARM AND ACTUALLY COOLED THEM A FEW DEGREES FROM THE PREVIOUS FORECAST. MODEL AGREEMENT CONTINUES THROUGH THE DAY WEDNESDAY AS A SHORTWAVE MOVING THROUGH THE NORTHERN STREAM DROPS FAR ENOUGH SOUTH TO CATCH THE DAKOTA UPPER LOW AND FINALLY PUSH IT EASTWARD. AT THIS POINT THE CALIFORNIA UPPER LOW WILL HAVE MOVED INTO THE FOUR CORNERS. THIS MAKES WEDNESDAY LOOK DRIER THAN WAS PREVIOUSLY FORECAST AS THE AREA SITS IN A SUBSIDENT REGION BEHIND THE PASSING UPPER LOW AND TOO FAR AHEAD OF THE FOUR CORNERS LOW TO REALLY EXPECT MUCH FOR PRECIPITATION. AT THIS POINT...DIDN/T GO COMPLETELY DRY FOR WEDNESDAY...AS THERE IS STILL A LACK OF CONFIDENCE IN THE MODEL SOLUTIONS. AT THIS POINT TRENDED PRECIPITATION FORECAST LOWER...WITH THE BETTER CHANCES FOR RAIN ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA. IN TURN...WITH LESSER PRECIPITATION EXPECTED...INCREASED TEMPERATURES A BIT FOR WEDNESDAY. THERE DOES LOOK TO BE A WARM FRONT LOCATED SOMEWHERE ACROSS KANSAS ON WEDNESDAY AFTERNOON...WHICH SHOULD BE THE FOCUS FOR STORM DEVELOPMENT. INSTABILITY IS DECENT...AND SHEAR IS BETWEEN 35 AND 45KTS SO COULD SEE SOME STRONGER STORMS. THIS BEING SAID...CURRENT THINKING IS THAT MOST OF THIS ACTIVITY WILL STAY SOUTH OF THE LOCAL AREA...MAINLY IN FAR SOUTHERN NEBRASKA AND KANSAS. BUT IF THIS BOUNDARY MEANDERS MAY NEED TO ADJUST THIS THINKING NORTHWARD. AT THIS POINT MODEL DIVERGENCE BEGINS WITH HOW THE UPPER LOW TO THE SOUTHWEST WILL PROGRESS. THE ECMWF AND GFS ARE FOR THE MOST PART BOTH WEAKENING THE LOW AND DEVELOPING ANOTHER OVER NORTHWEST MEXICO. THE GEM ON THE OTHER HAND QUICKLY PUSHES EVERYTHING TO THE EAST. CONFIDENCE LESSENS WITH PRECIPITATION CHANCES FOR THURSDAY AND FRIDAY...BUT THERE REMAINS SOME WEAK SIGNALS SO KEPT IT IN THE FORECAST FOR NOW. GOING INTO THE WEEKEND...A STRONG RIDGE BUILDS OVER THE WEST COAST. IN TURN...AN UPPER LEVEL TROUGH DIGS SOUTH ACROSS THE NORTHERN PLAINS AND GREAT LAKES REGION. THIS WILL PUSH A PRETTY STRONG COLD FRONT ACROSS THE AREA...MOST LIKELY SOMETIME SATURDAY MORNING. MAY HAVE A CHANCE FOR SOME SHOWERS WITH THE FRONTAL PASSAGE...BUT THE MAIN IMPACT WILL BE AGAIN PUSHING THE NEAR NORMAL TEMPERATURES SOUTHWARD...WITH TEMPERATURES AROUND 60 OR LOWER POSSIBLE FOR SATURDAY. ALSO...WITH THE COLDER AND DRIER AIRMASS ASSOCIATED WITH THIS SYSTEM...COULD ONCE AGAIN SEE LOWS SUNDAY MORNING IN THE MID 30S OR EVEN LOWER IN SOME LOCATIONS. IN BOTH CASES...DID NOT GO TO THE EXTREME AS THERE WILL LIKELY BE SOME CHANGES IN MODEL SOLUTIONS OVER THE NEXT SEVERAL DAYS. INSTEAD...JUST TRENDED COLDER FOR BOTH PERIODS. THE LONG TERM MODELS ARE FAIRLY PROGRESSIVE WITH THE UPPER FLOW FOR THE WEEKEND AND EARLY NEXT WEEK THOUGH SO THIS WOULD INDICATE THIS COLD SPELL WILL BE QUITE SHORT LIVED...WITH HIGHS RECOVERING TO AROUND 70 FOR SUNDAY AND POSSIBLY NEARING 80 BY MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1231 PM CDT MON MAY 6 2013 AVIATION CONCERNS FOR THE 18Z TAF PACKAGE INVOLVE SHOWER AND THUNDERSTORM CHANCES OVERNIGHT AND INTO TUESDAY MORNING. AFTER A RELATIVELY QUIET MONDAY AFTERNOON AND EVENING AN UPPER LEVEL LOW PRESSURE SYSTEM WILL BEGIN TO MOVE INTO THE HIGH PLAINS TONIGHT...WITH SHOWERS AND THUNDERSTORMS POSSIBLE AFTER 06Z. HAVE LEFT AS -RA FOR NOW TO BRING ATTENTION TO THE CHANCE FOR PRECIPITATION...HOWEVER UNCERTAINTIES STILL EXIST REGARDING EXACT TIMING AND WHETHER A -TSRA GROUP WILL BE NEEDED. THIS WILL BE REFINED AS THE PRECIPITATION CHANCES BECOME CLOSER TO THE CRITICAL SIX HOUR TIME FRAME. MVFR CIGS WILL BE LIKELY OVERNIGHT AND INTO TOMORROW MORNING. VISBYS MAY ALSO DROP BELOW VFR IN ANY MODERATE TO HEAVY SHOWER AND THUNDERSTORM ACTIVITY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CLB SHORT TERM...BROOKS LONG TERM...BROOKS AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1224 PM CDT MON MAY 6 2013 .UPDATE... ISSUED AT 1223 PM CDT MON MAY 6 2013 NO SUBSTANTIAL CHANGES FOR THIS ESTF UPDATE. DID RAISE HIGH TEMPS 2-3F W OF HWY 183. AM A BIT CONCERNED ABOUT DWPTS MIXING OUT THIS AFTN...BASED ON LBF RAOB. SEVERAL SITES TO THE W-NW OF THE FCST AREA AREA ALREADY 15-20% RH. HOWEVER...WEAK PRES GRADIENT PROBABLY MEANS WE DEAL WITH THE AIR MASS WE HAVE IN PLACE. SO NO CHANGES TO FCST DWPTS BUT WILL CONT TO MONITOR. DID LOWER SKY COVERAGE SOME. UPDATE ISSUED AT 717 AM CDT MON MAY 6 2013 SENT A QUICK ENHANCED SHORT-TERM FCST /ESTF/ UPDATE AS HOURLY TEMPS/DWPTS WERE RUNNING WAY ABOVE REALITY 12-13Z. STILL SEEING SHALLOW 1/4SM VSBY OR LESS WITHIN THE ADVY. SO NO CHANGES TO THE HEADLINE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM CDT MON MAY 6 2013 OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF OUR AREA THIS MORNING. GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST SITES BY 14Z. AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST 06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST. MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE 700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG. GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT. THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS ACROSS OUR CWA AS A RESULT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 403 AM CDT MON MAY 6 2013 TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND TEMPERATURES. AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS OVER THE NEXT COUPLE DAYS. FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG. TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1223 PM CDT MON MAY 6 2013 THIS AFTN: VFR WITH A FEW STRATOCU LIFTING TO NEAR 4K FT. LGT AND VARIABLE WINDS. TNGT: CLOUDS INCREASE AND DESCEND WITH MID-LVL CIGS AROUND 8K MOVING IN AFTER 06Z. WINDS ORGANIZE FROM THE SE BELOW 10 KTS. TUE THRU 18Z: VFR FOR NOW BUT THERE IS POTENTIAL FOR SCT SHWRS TO RESULT IN A PERIOD OF MVFR CIGS/VSBYS. THERE IS SOME POTENTIAL FOR THUNDER. SE WINDS WILL CONT BELOW 10 KTS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...BRYANT LONG TERM...JCB AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
717 AM CDT MON MAY 6 2013 .UPDATE... ISSUED AT 717 AM CDT MON MAY 6 2013 SENT A QUICK ENHANCED SHORT-TERM FCST /ESTF/ UPDATE AS HOURLY TEMPS/DWPTS WERE RUNNING WAY ABOVE REALITY 12-13Z. STILL SEEING SHALLOW 1/4SM VSBY OR LESS WITHIN THE ADVY. SO NO CHANGES TO THE HEADLINE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM CDT MON MAY 6 2013 OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF OUR AREA THIS MORNING. GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST SITES BY 14Z. AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST 06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST. MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE 700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG. GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT. THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS ACROSS OUR CWA AS A RESULT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 403 AM CDT MON MAY 6 2013 TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND TEMPERATURES. AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS OVER THE NEXT COUPLE DAYS. FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG. TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 515 AM CDT MON MAY 6 2013 LIFR TO VLIFR CONDITIONS EXPECTED UNTIL 14Z...WITH VFR CONDITIONS EXPECTED BY 14 AND BEYOND. DENSE FOG HAS INFILTRATED MUCH OF SOUTH CENTRAL NEBRASKA THIS MORNING WITH SEVERAL SITES NEAR KGRI AT OR BELOW 1/4SM. GIVEN THE VISIBILITY TRENDS AT KGRI THROUGH THE PAST COUPLE HOURS...OPTED TO GO WITH PREVAILING LIFR VISIBILITY THROUGH 14Z...WITH TEMPO VLIFR VISIBILITY ALSO THROUGH 14Z. THIS FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST- SUNRISE...WITH FULL VISIBILITY EXPECTED BY 14Z. SCATTERED MID TO HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS...ALTHOUGH A BROKEN DECK NEAR 5000FT AGL IS POSSIBLE TOWARDS THE END OF THE TAF PERIOD. THE PRESENCE OF A SURFACE RIDGE WILL KEEP THE SURFACE WIND LIGHT AND VARIABLE THIS MORNING...BEFORE BECOMING MORE ESTABLISHED FROM THE SOUTHEAST THIS AFTERNOON. THERE IS A CHANCE OF MEASURABLE PRECIPITATION AND CONVECTIVE ACTIVITY 06Z-12Z TUESDAY...HOWEVER THE PROBABILITY OF SUCH ACTIVITY BEING REALIZED AT KGRI IS TOO LOW FOR INSERTION INTO THE TAF AT THIS TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041- 046>049-060>064-072>077. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...BRYANT LONG TERM...JCB AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
637 AM CDT MON MAY 6 2013 .SYNOPSIS... ISSUED AT 407 AM CDT MON MAY 6 2013 H5 ANALYSIS TONIGHT HAS THREE AREAS OF CLOSED LOW PRESSURE OVER THE CONUS. THE FIRST WAS OVER NRN ALABAMA...THE SECOND OFF THE NRN CA COAST AND A THIRD WEAKER SYSTEM WAS NOTED OVER CENTRAL SOUTH DAKOTA. AT THE SURFACE...WEAK HIGH PRESSURE WAS ANCHORED ACROSS NORTHERN NEBRASKA AND SOUTHERN SOUTH DAKOTA ATTM. RADIATIONAL COOLING UNDERNEATH THE HIGH...HAS LED TO SOME PATCHY FOG ACROSS NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE PAST HOUR...WITH VISBYS DOWN TO QUARTER MILE AT ONEILL. COMPARED TO 24 HOURS AGO...TEMPERATURES ARE MUCH WARMER ATTM WITH 3 AM CDT TEMPS RANGING FROM THE LOWER 30S IN THE NORTHEAST...TO THE LOWER 40S IN THE EASTERN PANHANDLE AND FAR SOUTHWESTERN NEBRASKA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 407 AM CDT MON MAY 6 2013 THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS ARE TEMPERATURES TODAY...AND THE THREAT FOR THUNDERSTORMS LATER TONIGHT. FOR THIS MORNING...OBSERVATIONS...SATELLITE IMAGERY AND HIGHWAY CAMS...CONTINUE TO INDICATE FOG ACROSS THE NORTHEASTERN CWA ATTM. THE LATEST VISIBILITY FOR ONEILL IS AROUND A QUARTER MILE. DECIDED TO HOIST A DENSE FOG ADVISORY TO COVER THIS THREAT THROUGH MID MORNING. ATTM...THE DENSE FOG THREAT APPEARS LOCALIZED WITH THE LOWEST VISBYS IN LOW LYING AREAS AND RIVER VALLEYS. BASED ON THE HRRR AND NAM12 BL RH FIELD...FOG SHOULD QUICKLY BURN OFF BY MID MORNING...WITH VISBYS IMPROVING QUICKLY AFTER 14Z. BASED ON THE HRRR...THE GREATEST THREAT FOR FOG SHOULD REMAIN ALONG AND EAST OF HIGHWAY 183. FOR THE REMAINDER OF TODAY...SRLY WINDS WILL INCREASE THIS AFTERNOON AS HIGH PRESSURE MOVES EAST OF THE AREA...AND LEE TROUGHING DEEPENS ACROSS EASTERN WYOMING AND EASTERN COLORADO. THE SRLY WINDS...WILL PUSH WARMER AIR AND INCREASED LOW LEVEL MOISTURE FROM THE SRN PLAINS INTO WESTERN AND NORTH CENTRAL NEBRASKA. THIS WILL RESULT IN HIGHS IN THE MID TO UPPER 60S THIS AFTERNOON...WHICH IS A SMALL DECREASE IN THE LOWER 70S IN THE INHERITED FCST. HIGHS WERE LOWERED AS I AM ANTICIPATING ADDITIONAL HIGH CLOUDINESS TO PUSH INTO THE FORECAST AREA LATER THIS AFTERNOON FROM THE SRN ROCKIES. THIS CLOUDINESS IS IN ADVANCE OF AN APPROACHING DISTURBANCE...WHICH WILL BEGIN TO IMPACT THE FORECAST AREA LATER TONIGHT. PRECIPITATION CHANCES WILL BEGIN TO INCREASE OVERNIGHT TONIGHT AS MID LEVEL WAA BEGINS TO LIFT INTO THE CENTRAL PLAINS IN ADVANCE OF AN APPROACHING UPPER LEVEL DISTURBANCE. ELEVATED INSTABILITY WILL INCREASE OVERNIGHT PER H800 CALCULATED LI`S RANGE FROM -1 TO -3 OVERNIGHT ACROSS CENTRAL AND NORTHERN NEBRASKA. ADDITIONAL FORCING FOR TSRAS WILL COME FROM THE DEVELOPMENT OF A 30 KT LLJET WHICH WILL EXTEND FROM WESTERN KS INTO SWRN NEBRASKA AFTER 06Z TONIGHT. COVERAGE OF TSRAS IS EXPECTED TO BE LIMITED THOUGH AS SURFACE DEW POINTS WILL ONLY BE IN THE LOWER TO MID 40S. ATTM...NO SEVERE THUNDERSTORMS ARE EXPECTED OVERNIGHT...AS LIFT AND AVAILABLE CAPE WILL BE LIMITED. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM CDT MON MAY 6 2013 BY TUESDAY MORNING THERE REALLY WON/T BE MUCH MOVEMENT IN THE PRIMARY UPPER LEVEL SYSTEMS ACROSS THE CONUS. THE UPPER LOW OVER THE SOUTHEAST PART OF THE COUNTRY WILL HAVE MOVED INTO THE CAROLINAS...WHILE THE SYSTEM OFF THE CALIFORNIA COAST WILL JUST BE MOVING ONSHORE BY 12Z TUESDAY. ALSO...THE WEAK UPPER LOW NOW OVER SOUTH DAKOTA WILL STAY STATIONARY THROUGH TUESDAY MORNING. MODEL SOLUTIONS HAVE STARTED TO BECOME MORE IN LINE FOR TUESDAY. THE SYSTEM OVER THE SOUTHEAST WILL SLOWLY LIFT NORTH ALONG THE EAST COAST THROUGH THE WEEK...WHILE THE CALIFORNIA LOW MOVES ONSHORE TUESDAY AND INTO THE GREAT BASIN TUESDAY NIGHT. MEANWHILE...THE WEAK UPPER LOW OVER THE DAKOTAS WILL STAY IN THE AREA THROUGH AT LEAST TUESDAY NIGHT AS THE NORTHERN STREAM STAYS WELL TO THE NORTH LEAVING NOTHING TO KICK IT OUT OF THE AREA. MEANWHILE...A WEAK SHORTWAVE TROUGH EJECTS OUT OF THE WEST COAST TROUGH AND PUSHES INTO THE CENTRAL PLAINS. PRECIPITATION CHANCES WILL INCREASE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT AHEAD OF THE SHORTWAVE TROUGH MOVING INTO THE AREA. MOISTURE WILL BE ON THE RISE ON TUESDAY AHEAD OF THIS FEATURE AS WELL...WITH THE MODELS BEING FAIRLY IN TUNE WITH EACH OTHER BRINGING IN 50 DEGREE DEWPOINTS INTO THE EASTERN PARTS OF THE FORECAST AREA. THIS MOISTURE ALONG WITH SOME COOLER TEMPERATURES ALOFT /THANKS TO THE UPPER LOW HANGING AROUND/ WILL CAUSE THE AIR TO BE UNSTABLE FOR THUNDERSTORMS MAINLY STARTING TUESDAY AFTERNOON. LOOKING FOR QUITE A BIT OF CLOUD COVER THROUGH THE DAY TUESDAY AND WITH AT LEAST PERIODIC SHOWERS AND THUNDERSTORMS...NOT EXPECTING TEMPERATURES TO BE TOO WARM AND ACTUALLY COOLED THEM A FEW DEGREES FROM THE PREVIOUS FORECAST. MODEL AGREEMENT CONTINUES THROUGH THE DAY WEDNESDAY AS A SHORTWAVE MOVING THROUGH THE NORTHERN STREAM DROPS FAR ENOUGH SOUTH TO CATCH THE DAKOTA UPPER LOW AND FINALLY PUSH IT EASTWARD. AT THIS POINT THE CALIFORNIA UPPER LOW WILL HAVE MOVED INTO THE FOUR CORNERS. THIS MAKES WEDNESDAY LOOK DRIER THAN WAS PREVIOUSLY FORECAST AS THE AREA SITS IN A SUBSIDENT REGION BEHIND THE PASSING UPPER LOW AND TOO FAR AHEAD OF THE FOUR CORNERS LOW TO REALLY EXPECT MUCH FOR PRECIPITATION. AT THIS POINT...DIDN/T GO COMPLETELY DRY FOR WEDNESDAY...AS THERE IS STILL A LACK OF CONFIDENCE IN THE MODEL SOLUTIONS. AT THIS POINT TRENDED PRECIPITATION FORECAST LOWER...WITH THE BETTER CHANCES FOR RAIN ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA. IN TURN...WITH LESSER PRECIPITATION EXPECTED...INCREASED TEMPERATURES A BIT FOR WEDNESDAY. THERE DOES LOOK TO BE A WARM FRONT LOCATED SOMEWHERE ACROSS KANSAS ON WEDNESDAY AFTERNOON...WHICH SHOULD BE THE FOCUS FOR STORM DEVELOPMENT. INSTABILITY IS DECENT...AND SHEAR IS BETWEEN 35 AND 45KTS SO COULD SEE SOME STRONGER STORMS. THIS BEING SAID...CURRENT THINKING IS THAT MOST OF THIS ACTIVITY WILL STAY SOUTH OF THE LOCAL AREA...MAINLY IN FAR SOUTHERN NEBRASKA AND KANSAS. BUT IF THIS BOUNDARY MEANDERS MAY NEED TO ADJUST THIS THINKING NORTHWARD. AT THIS POINT MODEL DIVERGENCE BEGINS WITH HOW THE UPPER LOW TO THE SOUTHWEST WILL PROGRESS. THE ECMWF AND GFS ARE FOR THE MOST PART BOTH WEAKENING THE LOW AND DEVELOPING ANOTHER OVER NORTHWEST MEXICO. THE GEM ON THE OTHER HAND QUICKLY PUSHES EVERYTHING TO THE EAST. CONFIDENCE LESSENS WITH PRECIPITATION CHANCES FOR THURSDAY AND FRIDAY...BUT THERE REMAINS SOME WEAK SIGNALS SO KEPT IT IN THE FORECAST FOR NOW. GOING INTO THE WEEKEND...A STRONG RIDGE BUILDS OVER THE WEST COAST. IN TURN...AN UPPER LEVEL TROUGH DIGS SOUTH ACROSS THE NORTHERN PLAINS AND GREAT LAKES REGION. THIS WILL PUSH A PRETTY STRONG COLD FRONT ACROSS THE AREA...MOST LIKELY SOMETIME SATURDAY MORNING. MAY HAVE A CHANCE FOR SOME SHOWERS WITH THE FRONTAL PASSAGE...BUT THE MAIN IMPACT WILL BE AGAIN PUSHING THE NEAR NORMAL TEMPERATURES SOUTHWARD...WITH TEMPERATURES AROUND 60 OR LOWER POSSIBLE FOR SATURDAY. ALSO...WITH THE COLDER AND DRIER AIRMASS ASSOCIATED WITH THIS SYSTEM...COULD ONCE AGAIN SEE LOWS SUNDAY MORNING IN THE MID 30S OR EVEN LOWER IN SOME LOCATIONS. IN BOTH CASES...DID NOT GO TO THE EXTREME AS THERE WILL LIKELY BE SOME CHANGES IN MODEL SOLUTIONS OVER THE NEXT SEVERAL DAYS. INSTEAD...JUST TRENDED COLDER FOR BOTH PERIODS. THE LONG TERM MODELS ARE FAIRLY PROGRESSIVE WITH THE UPPER FLOW FOR THE WEEKEND AND EARLY NEXT WEEK THOUGH SO THIS WOULD INDICATE THIS COLD SPELL WILL BE QUITE SHORT LIVED...WITH HIGHS RECOVERING TO AROUND 70 FOR SUNDAY AND POSSIBLY NEARING 80 BY MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 637 AM CDT MON MAY 6 2013 FOR THE KLBF TERMINAL...SCATTERED HIGH CLOUDINESS IS EXPECTED TODAY AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE SOUTHERN ROCKIES. CIGS WILL LOWER TO 10000 TO 15000 FT TONIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS SOUTHWESTERN AND CENTRAL NEBRASKA OVERNIGHT TONIGHT. WILL FORGO MENTION OF THUNDERSTORMS IN THE 12Z KLBF TAF AS COVERAGE WILL BE ISOLATED. FOR THE KVTN TERMINAL...MAINLY CLEAR SKIES ARE EXPECTED. SOME MID LEVEL CLOUDINESS WILL MOVE INTO NORTHERN NEBRASKA LATER TONIGHT...WITH CIGS AROUND 15000 FT AGL. WINDS WILL BE FROM THE SOUTH OR SOUTHEAST AT AROUND 10 KTS THROUGH 12Z TUESDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ007-010- 028-029. && $$ SYNOPSIS...CLB SHORT TERM...BROOKS LONG TERM...BROOKS AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
515 AM CDT MON MAY 6 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM CDT MON MAY 6 2013 OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF OUR AREA THIS MORNING. GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST SITES BY 14Z. AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST 06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST. MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE 700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG. GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT. THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS ACROSS OUR CWA AS A RESULT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 403 AM CDT MON MAY 6 2013 TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND TEMPERATURES. AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS OVER THE NEXT COUPLE DAYS. FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG. TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 515 AM CDT MON MAY 6 2013 LIFR TO VLIFR CONDITIONS EXPECTED UNTIL 14Z...WITH VFR CONDITIONS EXPECTED BY 14 AND BEYOND. DENSE FOG HAS INFILTRATED MUCH OF SOUTH CENTRAL NEBRASKA THIS MORNING WITH SEVERAL SITES NEAR KGRI AT OR BELOW 1/4SM. GIVEN THE VISIBILITY TRENDS AT KGRI THROUGH THE PAST COUPLE HOURS...OPTED TO GO WITH PREVAILING LIFR VISIBILITY THROUGH 14Z...WITH TEMPO VLIFR VISIBILITY ALSO THROUGH 14Z. THIS FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST- SUNRISE...WITH FULL VISIBILITY EXPECTED BY 14Z. SCATTERED MID TO HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS...ALTHOUGH A BROKEN DECK NEAR 5000FT AGL IS POSSIBLE TOWARDS THE END OF THE TAF PERIOD. THE PRESENCE OF A SURFACE RIDGE WILL KEEP THE SURFACE WIND LIGHT AND VARIABLE THIS MORNING...BEFORE BECOMING MORE ESTABLISHED FROM THE SOUTHEAST THIS AFTERNOON. THERE IS A CHANCE OF MEASURABLE PRECIPITATION AND CONVECTIVE ACTIVITY 06Z-12Z TUESDAY...HOWEVER THE PROBABILITY OF SUCH ACTIVITY BEING REALIZED AT KGRI IS TOO LOW FOR INSERTION INTO THE TAF AT THIS TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041- 046>049-061>064-074>077. KS...NONE. && $$ SHORT TERM...BRYANT LONG TERM...JCB AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
408 AM CDT MON MAY 6 2013 .SYNOPSIS... ISSUED AT 407 AM CDT MON MAY 6 2013 H5 ANALYSIS TONIGHT HAS THREE AREAS OF CLOSED LOW PRESSURE OVER THE CONUS. THE FIRST WAS OVER NRN ALABAMA...THE SECOND OFF THE NRN CA COAST AND A THIRD WEAKER SYSTEM WAS NOTED OVER CENTRAL SOUTH DAKOTA. AT THE SURFACE...WEAK HIGH PRESSURE WAS ANCHORED ACROSS NORTHERN NEBRASKA AND SOUTHERN SOUTH DAKOTA ATTM. RADIATIONAL COOLING UNDERNEATH THE HIGH...HAS LED TO SOME PATCHY FOG ACROSS NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE PAST HOUR...WITH VISBYS DOWN TO QUARTER MILE AT ONEILL. COMPARED TO 24 HOURS AGO...TEMPERATURES ARE MUCH WARMER ATTM WITH 3 AM CDT TEMPS RANGING FROM THE LOWER 30S IN THE NORTHEAST...TO THE LOWER 40S IN THE EASTERN PANHANDLE AND FAR SOUTHWESTERN NEBRASKA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 407 AM CDT MON MAY 6 2013 THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS ARE TEMPERATURES TODAY...AND THE THREAT FOR THUNDERSTORMS LATER TONIGHT. FOR THIS MORNING...OBSERVATIONS...SATELLITE IMAGERY AND HIGHWAY CAMS...CONTINUE TO INDICATE FOG ACROSS THE NORTHEASTERN CWA ATTM. THE LATEST VISIBILITY FOR ONEILL IS AROUND A QUARTER MILE. DECIDED TO HOIST A DENSE FOG ADVISORY TO COVER THIS THREAT THROUGH MID MORNING. ATTM...THE DENSE FOG THREAT APPEARS LOCALIZED WITH THE LOWEST VISBYS IN LOW LYING AREAS AND RIVER VALLEYS. BASED ON THE HRRR AND NAM12 BL RH FIELD...FOG SHOULD QUICKLY BURN OFF BY MID MORNING...WITH VISBYS IMPROVING QUICKLY AFTER 14Z. BASED ON THE HRRR...THE GREATEST THREAT FOR FOG SHOULD REMAIN ALONG AND EAST OF HIGHWAY 183. FOR THE REMAINDER OF TODAY...SRLY WINDS WILL INCREASE THIS AFTERNOON AS HIGH PRESSURE MOVES EAST OF THE AREA...AND LEE TROUGHING DEEPENS ACROSS EASTERN WYOMING AND EASTERN COLORADO. THE SRLY WINDS...WILL PUSH WARMER AIR AND INCREASED LOW LEVEL MOISTURE FROM THE SRN PLAINS INTO WESTERN AND NORTH CENTRAL NEBRASKA. THIS WILL RESULT IN HIGHS IN THE MID TO UPPER 60S THIS AFTERNOON...WHICH IS A SMALL DECREASE IN THE LOWER 70S IN THE INHERITED FCST. HIGHS WERE LOWERED AS I AM ANTICIPATING ADDITIONAL HIGH CLOUDINESS TO PUSH INTO THE FORECAST AREA LATER THIS AFTERNOON FROM THE SRN ROCKIES. THIS CLOUDINESS IS IN ADVANCE OF AN APPROACHING DISTURBANCE...WHICH WILL BEGIN TO IMPACT THE FORECAST AREA LATER TONIGHT. PRECIPITATION CHANCES WILL BEGIN TO INCREASE OVERNIGHT TONIGHT AS MID LEVEL WAA BEGINS TO LIFT INTO THE CENTRAL PLAINS IN ADVANCE OF AN APPROACHING UPPER LEVEL DISTURBANCE. ELEVATED INSTABILITY WILL INCREASE OVERNIGHT PER H800 CALCULATED LI`S RANGE FROM -1 TO -3 OVERNIGHT ACROSS CENTRAL AND NORTHERN NEBRASKA. ADDITIONAL FORCING FOR TSRAS WILL COME FROM THE DEVELOPMENT OF A 30 KT LLJET WHICH WILL EXTEND FROM WESTERN KS INTO SWRN NEBRASKA AFTER 06Z TONIGHT. COVERAGE OF TSRAS IS EXPECTED TO BE LIMITED THOUGH AS SURFACE DEW POINTS WILL ONLY BE IN THE LOWER TO MID 40S. ATTM...NO SEVERE THUNDERSTORMS ARE EXPECTED OVERNIGHT...AS LIFT AND AVAILABLE CAPE WILL BE LIMITED. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM CDT MON MAY 6 2013 BY TUESDAY MORNING THERE REALLY WON/T BE MUCH MOVEMENT IN THE PRIMARY UPPER LEVEL SYSTEMS ACROSS THE CONUS. THE UPPER LOW OVER THE SOUTHEAST PART OF THE COUNTRY WILL HAVE MOVED INTO THE CAROLINAS...WHILE THE SYSTEM OFF THE CALIFORNIA COAST WILL JUST BE MOVING ONSHORE BY 12Z TUESDAY. ALSO...THE WEAK UPPER LOW NOW OVER SOUTH DAKOTA WILL STAY STATIONARY THROUGH TUESDAY MORNING. MODEL SOLUTIONS HAVE STARTED TO BECOME MORE IN LINE FOR TUESDAY. THE SYSTEM OVER THE SOUTHEAST WILL SLOWLY LIFT NORTH ALONG THE EAST COAST THROUGH THE WEEK...WHILE THE CALIFORNIA LOW MOVES ONSHORE TUESDAY AND INTO THE GREAT BASIN TUESDAY NIGHT. MEANWHILE...THE WEAK UPPER LOW OVER THE DAKOTAS WILL STAY IN THE AREA THROUGH AT LEAST TUESDAY NIGHT AS THE NORTHERN STREAM STAYS WELL TO THE NORTH LEAVING NOTHING TO KICK IT OUT OF THE AREA. MEANWHILE...A WEAK SHORTWAVE TROUGH EJECTS OUT OF THE WEST COAST TROUGH AND PUSHES INTO THE CENTRAL PLAINS. PRECIPITATION CHANCES WILL INCREASE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT AHEAD OF THE SHORTWAVE TROUGH MOVING INTO THE AREA. MOISTURE WILL BE ON THE RISE ON TUESDAY AHEAD OF THIS FEATURE AS WELL...WITH THE MODELS BEING FAIRLY IN TUNE WITH EACH OTHER BRINGING IN 50 DEGREE DEWPOINTS INTO THE EASTERN PARTS OF THE FORECAST AREA. THIS MOISTURE ALONG WITH SOME COOLER TEMPERATURES ALOFT /THANKS TO THE UPPER LOW HANGING AROUND/ WILL CAUSE THE AIR TO BE UNSTABLE FOR THUNDERSTORMS MAINLY STARTING TUESDAY AFTERNOON. LOOKING FOR QUITE A BIT OF CLOUD COVER THROUGH THE DAY TUESDAY AND WITH AT LEAST PERIODIC SHOWERS AND THUNDERSTORMS...NOT EXPECTING TEMPERATURES TO BE TOO WARM AND ACTUALLY COOLED THEM A FEW DEGREES FROM THE PREVIOUS FORECAST. MODEL AGREEMENT CONTINUES THROUGH THE DAY WEDNESDAY AS A SHORTWAVE MOVING THROUGH THE NORTHERN STREAM DROPS FAR ENOUGH SOUTH TO CATCH THE DAKOTA UPPER LOW AND FINALLY PUSH IT EASTWARD. AT THIS POINT THE CALIFORNIA UPPER LOW WILL HAVE MOVED INTO THE FOUR CORNERS. THIS MAKES WEDNESDAY LOOK DRIER THAN WAS PREVIOUSLY FORECAST AS THE AREA SITS IN A SUBSIDENT REGION BEHIND THE PASSING UPPER LOW AND TOO FAR AHEAD OF THE FOUR CORNERS LOW TO REALLY EXPECT MUCH FOR PRECIPITATION. AT THIS POINT...DIDN/T GO COMPLETELY DRY FOR WEDNESDAY...AS THERE IS STILL A LACK OF CONFIDENCE IN THE MODEL SOLUTIONS. AT THIS POINT TRENDED PRECIPITATION FORECAST LOWER...WITH THE BETTER CHANCES FOR RAIN ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA. IN TURN...WITH LESSER PRECIPITATION EXPECTED...INCREASED TEMPERATURES A BIT FOR WEDNESDAY. THERE DOES LOOK TO BE A WARM FRONT LOCATED SOMEWHERE ACROSS KANSAS ON WEDNESDAY AFTERNOON...WHICH SHOULD BE THE FOCUS FOR STORM DEVELOPMENT. INSTABILITY IS DECENT...AND SHEAR IS BETWEEN 35 AND 45KTS SO COULD SEE SOME STRONGER STORMS. THIS BEING SAID...CURRENT THINKING IS THAT MOST OF THIS ACTIVITY WILL STAY SOUTH OF THE LOCAL AREA...MAINLY IN FAR SOUTHERN NEBRASKA AND KANSAS. BUT IF THIS BOUNDARY MEANDERS MAY NEED TO ADJUST THIS THINKING NORTHWARD. AT THIS POINT MODEL DIVERGENCE BEGINS WITH HOW THE UPPER LOW TO THE SOUTHWEST WILL PROGRESS. THE ECMWF AND GFS ARE FOR THE MOST PART BOTH WEAKENING THE LOW AND DEVELOPING ANOTHER OVER NORTHWEST MEXICO. THE GEM ON THE OTHER HAND QUICKLY PUSHES EVERYTHING TO THE EAST. CONFIDENCE LESSENS WITH PRECIPITATION CHANCES FOR THURSDAY AND FRIDAY...BUT THERE REMAINS SOME WEAK SIGNALS SO KEPT IT IN THE FORECAST FOR NOW. GOING INTO THE WEEKEND...A STRONG RIDGE BUILDS OVER THE WEST COAST. IN TURN...AN UPPER LEVEL TROUGH DIGS SOUTH ACROSS THE NORTHERN PLAINS AND GREAT LAKES REGION. THIS WILL PUSH A PRETTY STRONG COLD FRONT ACROSS THE AREA...MOST LIKELY SOMETIME SATURDAY MORNING. MAY HAVE A CHANCE FOR SOME SHOWERS WITH THE FRONTAL PASSAGE...BUT THE MAIN IMPACT WILL BE AGAIN PUSHING THE NEAR NORMAL TEMPERATURES SOUTHWARD...WITH TEMPERATURES AROUND 60 OR LOWER POSSIBLE FOR SATURDAY. ALSO...WITH THE COLDER AND DRIER AIRMASS ASSOCIATED WITH THIS SYSTEM...COULD ONCE AGAIN SEE LOWS SUNDAY MORNING IN THE MID 30S OR EVEN LOWER IN SOME LOCATIONS. IN BOTH CASES...DID NOT GO TO THE EXTREME AS THERE WILL LIKELY BE SOME CHANGES IN MODEL SOLUTIONS OVER THE NEXT SEVERAL DAYS. INSTEAD...JUST TRENDED COLDER FOR BOTH PERIODS. THE LONG TERM MODELS ARE FAIRLY PROGRESSIVE WITH THE UPPER FLOW FOR THE WEEKEND AND EARLY NEXT WEEK THOUGH SO THIS WOULD INDICATE THIS COLD SPELL WILL BE QUITE SHORT LIVED...WITH HIGHS RECOVERING TO AROUND 70 FOR SUNDAY AND POSSIBLY NEARING 80 BY MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1225 AM CDT MON MAY 6 2013 VISUAL FLIGHT RULES WILL CONTINUE OVER WESTERN NEBRASKA THROUGH MONDAY. LIGHT AND VARIABLE WINDS WILL INCREASE AND BECOME SOUTHEAST MONDAY AFTERNOON TO AROUND 10KTS. && .LBF WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ007-010- 028-029. && $$ SYNOPSIS...CLB SHORT TERM...BROOKS LONG TERM...BROOKS AVIATION...POWER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
403 AM CDT MON MAY 6 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM CDT MON MAY 6 2013 OVERNIGHT UPPER AIR ANALYSIS INDICATES A MID TO UPPER LEVEL OMEGA PATTERN WITH MID TO UPPER LEVEL LOWS OVER THE WESTERN AND SOUTHEASTERN CONUS...AND RIDGING OVER THE CENTRAL CONUS. MID AND UPPER LEVEL JET ENERGY REMAINS RELEGATED WELL TO OUR SOUTH AND AS A RESULT...MID AND UPPER LEVEL FLOW OVER THE CENTRAL PLAINS REMAINS VERY WEAK. WATER VAPOR IMAGERY SHOWS THE TWO AFOREMENTIONED MID LEVEL LOWS...WITH INCREASED VALUES OF MID LEVEL MOISTURE WRAPPING AROUND THE SOUTHEASTERN CONUS LOW INTO PORTIONS OF THE OHIO RIVER VALLEY AND THE MID MISSISSIPPI VALLEY...AND INCREASED VALUES OF MID LEVEL MOISTURE ALSO NOTED OVER THE WESTERN CONUS AHEAD OF THE WESTERN CONUS LOW. WATER VAPOR IMAGERY ALSO INDICATES A SUBTLE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN CONUS...PIVOTING TO THE SOUTHEAST OF THE WESTERN CONUS MID LEVEL LOW. AT THE SURFACE A RIDGE OF HIGH BAROMETRIC PRESSURE EXISTS FROM NORTH TO SOUTH ACROSS OUR CWA AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS LIGHT. THE LIGHT LOW LEVEL WIND FIELD...WORKING IN CONCERT WITH DECREASING LOW LEVEL DEWPOINT DEPRESSIONS...HAS PROMOTED THE DEVELOPMENT OF FOG ACROSS MUCH OF OUR AREA THIS MORNING. GIVEN THE CURRENT FOG BEING OBSERVED ACROSS THE AREA...WILL CONTINUE FOG MENTION IN THE FORECAST THROUGH 14Z THIS MORNING. AS OF 09Z KODX...KHSI AND KAUH HAVE DROPPED TO 1/4SM WITH SEVERAL OTHER SITE IN THE AREA ALSO DROPPING NEAR 1/4SM. GIVEN ALL THIS...WENT AHEAD WITH A DENSE FOG ADVISORY...FOR LOCATIONS GENERALLY EAST OF A KODX TO KEAR LINE AND NORTH OF HIGHWAY 6. THIS FOG APPEARS TO BE VERY SHALLOW...BASED ON LAPS AND RAP ANALYSIS POINT SOUNDINGS AS WELL AS OBSERVATION HERE AT THE OFFICE. AS A RESULT...INCREASED DIABATIC HEATING AND RESULTANT INCREASING BOUNDARY LAYER DEPTH AND MIXING SHOULD ALLOW THE FOG TO QUICKLY DISSIPATE POST-SUNRISE...WITH FULL VISIBILITY EXPECTED AT MOST SITES BY 14Z. AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED TO KEEP OUR AREA DRY TODAY. THE SUBTLE MID LEVEL SHORT WAVE...CURRENTLY OVER THE SOUTHWESTERN CONUS...IS EXPECTED TO CONTINUE MOVING EAST/NORTHEAST TODAY AND BY THIS EVENING...SHOULD BE MOVING ACROSS THE SOUTHERN TO CENTRAL ROCKY MOUNTAIN RANGE. MID LEVEL THERMAL ADVECTION AND RESULTANT OMEGA AHEAD OF THE SHORT WAVE TROUGH AXIS APPEARS AS THOUGH IT WILL BE STRONG ENOUGH FOR PRECIPITATION PRODUCTION ACROSS THE SOUTHERN TO CENTRAL HIGH PLAINS LATE THIS AFTERNOON INTO THIS EVENING. SHORTLY AFTER SUNSET TONIGHT...A ~30KT 850MB JET STREAK IS EXPECTED TO DEVELOP FROM SOUTH TO NORTH ACROSS THE SOUTHERN AND CENTRAL HIGH PLAINS. THIS 850MB JET STREAK IS THEN EXPECTED TO PROPAGATE EAST SOMEWHAT DURING THE OVERNIGHT HOURS AND BY 12Z TUESDAY...THE EASTERN PERIPHERY OF THIS 850MB JET AXIS WILL BRUSH UP AGAINST WEST/SOUTHWESTERN PORTIONS OF OUR CWA. LOW LEVEL THERMAL ADVECTION ALONG THE 850MB JET STREAK AXIS APPEARS AS THOUGH IT WILL ALLOW LATE AFTERNOON/EVENING PRECIPITATION ACROSS THE HIGH PLAINS TO HOLD TOGETHER POST-SUNSET...AND MOVE INTO WESTERN/SOUTHWESTERN PORTIONS OF OUR CWA 06-12Z TUESDAY. THIS IS A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN. GIVEN THE MODEL AGREEMENT AND THE APPARENT LIKELIHOOD THAT SOME LOCATIONS ACROSS OUR WEST/SOUTHWEST COULD PICKUP UPWARDS OF A TENTH OF AN INCH OF PRECIPITATION...OPTED TO INCREASE POPS INTO THE 40-50% RANGE ACROSS OUR FAR WEST/SOUTHWEST 06-12Z TUESDAY. LOCATIONS FATHER EAST/NORTHEAST ALSO HAVE POPS IN PLACE FOR TONIGHT...ALBEIT SUBSTANTIALLY LOWER IN THE 20-30% RANGE AS CONFIDENCE IS NOT NEARLY AS HIGH THAT FAR EAST WITH THE 850MB JET STREAK AXIS EXPECTED TO REMAIN FARTHER WEST. MOISTURE FLUX ALONG THE 850MB JET STREAK AXIS...AS WELL AS THE 700MB JET STREAK AXIS...WORKING IN CONCERT WITH INCREASING MID LEVEL LAPSE RATES WITH THE APPROACH OF THE SUBTLE MID LEVEL SHORT WAVE...IS EXPECTED TO PROVIDE INCREASING POTENTIAL INSTABILITY ACROSS OUR AREA TONIGHT. THE NAM IN PARTICULAR SUGGESTS PARCELS ROOTED TO BETWEEN 850MB AND 750MB WILL HAVE 50-100J/KG OF CAPE TO WORK WITH AND CIN RANGING BETWEEN NEAR-ZERO AND AROUND -20J/KG. GIVEN ALL THIS...ISOLATED CONVECTION CERTAINLY SEEMS POSSIBLE EMBEDDED WITHIN THE STRATIFORM RAIN EVENT OCCURRING ALONG THE LOW LEVEL JET AXIS. GIVEN ALL THIS WENT AHEAD AND ADDED ISOLATED THUNDER MENTION TO THE FORECAST FOR OUR CWA FOR TONIGHT. THE SURFACE RIDGE CURRENTLY OVER THE AREA IS EXPECTED TO PUSH EAST LATER TODAY...ALLOWING FOR WEAK LOW LEVEL RETURN FLOW ACROSS MUCH OF OUR AREA BY THIS AFTERNOON. SUBTLE LOW LEVEL WARM AIR ADVECTION...AS WELL AS INCREASED DIABATIC HEATING...WHEN COMPARED TO SUNDAY SHOULD ALLOW FOR A WARMER DAY ACROSS OUR CWA TODAY. AN AFTERNOON HIGH TEMPERATURE IN THE UPPER 60S TO LOWER 70S IS FORECAST FOR MOST LOCATIONS FOR TODAY AS A RESULT. INCREASING CLOUD COVER...POSSIBLE PRECIPITATION...AND CONTINUED SOUTHEASTERLY LOW LEVEL FLOW SHOULD PRESENT A WARMER OVERNIGHT LOW TEMPERATURE TONIGHT WHEN COMPARED TO EARLY THIS MORNING. A TUESDAY MORNING LOW TEMPERATURE IN THE MID TO UPPER 40S IS FORECAST FOR MOST LOCATIONS ACROSS OUR CWA AS A RESULT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 403 AM CDT MON MAY 6 2013 TUESDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY THROUGH SATURDAY AND TEMPERATURES. AN UNSETTLED PATTERN WILL BE FOUND ACROSS THE CENTRAL PLAINS FOR TUESDAY THROUGH SATURDAY. A WEAK RIDGE SETS UP BETWEEN A STRONG UPPER LEVEL LOW TO THE WEST AND ANOTHER TO THE EAST. DESPITE THE RIDGE...THERE WILL BE SEVERAL RELATIVELY WEAK UPPER LEVEL LOW PRESSURE SYSTEMS THAT WILL AFFECT THE AREA FOR THE TUESDAY THROUGH SATURDAY PERIOD. DO NOT EXPECT THAT IT WILL BE RAINING ALL OF THE TIME FOR EACH OF THESE PERIODS...BUT THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS ON AND OFF THROUGH THE PERIOD. THE STRONGEST UPPER LEVEL LOWS THAT MOVE THROUGH THE AREA WILL BE FOR TUESDAY AND TUESDAY NIGHT AND AGAIN WEDNESDAY NIGHT. THESE WILL BRING THE BEST CHANCES FOR PRECIPITATION. THE MUCAPE FOR TUESDAY AFTERNOON AND EVENING WILL REACH AROUND 750 J/KG WHICH SHOULD BE ENOUGH FOR SOME ISOLATED SEVERE WEATHER...BUT WEDNESDAY AFTERNOON AND EVENING MUCAPE VALUES APPROACH 2500 J/KG WHICH WOULD INDICATE A BETTER CHANCE FOR SOME SEVERE STORMS. THERE ARE STILL SOME DIFFERENCES IN THE MODELS AND WILL HAVE TO WATCH TO SEE HOW MUCH CHANGE THERE IS OVER THE NEXT COUPLE DAYS. FOR THURSDAY THROUGH SATURDAY THE UPPER LEVEL LOW IN THE WESTERN CONUS WILL DRIFT TO THE EAST AND INTO THE PLAINS. THIS WILL CONTINUE TO BRING CHANCES FOR SHOWERS WITH SOME ISOLATED THUNDERSTORMS. MU CAPE VALUES DECREASE TO LESS THAN 200 J/KG. TEMPERATURES SHOULD REMAIN AROUND NORMAL FOR THIS TIME OF YEAR THROUGH FRIDAY...BUT AS A COLD FRONT MOVES SOUTH INTO THE AREA ON SATURDAY EXPECT SOME SHOWERS AND THUNDERSTORMS BEHIND THE FRONT AND TEMPERATURES WILL COOL OFF A FEW DEGREES. A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE REGION FOR SATURDAY NIGHT INTO SUNDAY AND TEMPERATURES WILL REMAIN A BIT COOLER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1229 AM CDT MON MAY 6 2013 VFR CONDITIONS EXPECTED THROUGH MUCH OF THE TAF PERIOD...ALTHOUGH IFR CONDITIONS WILL BE POSSIBLE 10-14Z. SCATTERED MID TO HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS. THE PRESENCE OF A SURFACE RIDGE WILL KEEP THE SURFACE WIND LIGHT AND VARIABLE THROUGH TONIGHT...BEFORE BECOMING MORE ESTABLISHED FROM THE SOUTHEAST DURING THE DAY MONDAY. A DECREASING LOW LEVEL DEWPOINT DEPRESSION...WORKING IN CONCERT WITH THE AFOREMENTIONED LIGHT SURFACE WIND...MAY PROMOTE FOG DEVELOPMENT AT KGRI BETWEEN 10Z AND 14Z THIS MORNING. CONFIDENCE OF SUCH VISIBILITY RESTRICTION ACTUALLY OCCURRING IS ABOUT 50%...WITH THE SITUATION LIKELY BECOMING MORE CLEAR BETWEEN 10Z AND 12Z. FOR NOW WILL GO WITH A PREVAILING IFR VISIBILITY AND AN MVFR CEILING...PER GUIDANCE...10-14Z AND IF NECESSARY...UPDATE AS WE APPROACH SUNRISE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041- 046>049-061>064-074>077. KS...NONE. && $$ SHORT TERM...BRYANT LONG TERM...JCB AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1229 AM CDT MON MAY 6 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 345 PM CDT SUN MAY 5 2013 OTHER THAN THE FAIRLY LOW PROBABILITY OF SOME PATCHY FOG OVERNIGHT...THE NEXT 24 HOURS ARE LOOKING DRY AND RATHER UNEVENTFUL...AS TEMPERATURES FINALLY MAKE A LEGITIMATE RUN BACK TOWARD 70 DEGREES ON MONDAY. 19Z OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A BROAD...ROUGHLY 1022 MILLIBAR NORTH-SOUTH ORIENTED RIDGE AXIS EXTENDING SOUTHWARD ACROSS THE CENTRAL CONUS...IN THE WAKE OF THE DEPARTED SURFACE LOW REFLECTION OF THE SLOW-MOVING CUT OFF UPPER LOW. BREEZES THIS AFTERNOON ACROSS THE CWA ARE GENERALLY OUT OF THE NORTH AT SUSTAINED SPEEDS 10-15 MPH WITH SOME HIGHER GUSTS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A SPLIT-FLOW UPPER AIR PATTERN THAT WILL DEFINE MUCH OF THE WEEK...WITH THE CENTRAL PLAINS LOCATED NORTH OF THE SOUTHERN STREAM AND SOUTH OF THE NORTHERN STREAM. DIRECTLY OVERHEAD IN THE MID LEVELS...FAIRLY WEAK WEST-NORTHWEST FLOW PREVAILS...AS THE CENTRAL PLAINS LIES IN BETWEEN TWO DOMINANT CLOSED 500 MILLIBAR LOWS..ONE DEPARTING ACROSS THE SOUTHEAST STATES...AND ANOTHER CENTERED JUST OFF THE CA COAST. IN BETWEEN...A MID/UPPER RIDGE EXTENDS NORTH TOWARD THE CENTRAL PLAINS FROM MEXICO...BUT WITH ANOTHER SMALL-SCALE CUT CLOSED MID LEVEL LOW SPINNING JUST TO THE NORTH OVER SD. AS OUTLINED IN THE EARLIER DISCUSSION...SKY COVER AND RESULTANT TEMPS WERE AT THE MERCY OF LOW STRATUS SCATTERING OUT AND/OR CLEARING FROM WEST-EAST...AND ALL THINGS CONSIDERED...THINGS HAVE ACTUALLY WORKED OUT FAIRLY WELL WITH ROUGHLY THE WESTERN 2/3 OF THE CWA NOW PREDOMINANTLY SUNNY-PARTLY CLOUDY AT THIS HOUR...WHILE MOSTLY CLOUDY SKIES ARE HANGING ON LONGER MAINLY EAST OF HIGHWAY 14. HIGH TEMPS APPEAR ON TRACK TO RANGE FROM THE UPPER 50S NORTHEAST TO MID 60S SOUTHWEST. FORTUNATELY FOR FIRE WEATHER CONCERNS...WINDS ARE GUSTING WELL UNDER 25 MPH...AS DEWPOINTS HAVE CRASHED ENOUGH TO DROP RELATIVE HUMIDITY VALUES TO NEAR/SLIGHTLY BELOW 20 PERCENT IN THE EXTREME WESTERN CWA...MAINLY WESTERN DAWSON/GOSPER/FURNAS COUNTIES. HEADING INTO THIS EVENING/TONIGHT...WILL RUN WITH THE ASSUMPTION THAT THE CURRENTLY ERODING STRATUS DECK WILL CONTINUE TO FADE AWAY EASTWARD WITH TIME INTO THE OAX/TOP AREAS...AND NOT COMPLETELY STALL OUT IN OUR EASTERN COUNTIES OR EVEN PUSH BACK WEST. HOWEVER...AM NOT 100 PERCENT CONFIDENT IN THIS...GIVEN THAT STEERING FLOW AT 900MB DOES TURN MORE EASTERLY TONIGHT...SO WILL HAVE TO KEEP AN EYE ON THESE LOW LEVEL CLOUD TRENDS. OTHERWISE...A GRADUAL INCREASE IN MAINLY THIN MID/HIGH CLOUDS WILL OCCUR TONIGHT...IN RESPONSE TO SUBTLE...LOW AMPLITUDE ENERGY LIFTING NORTHEAST TOWARD THE CENTRAL PLAINS OUT AHEAD OF THE AFOREMENTIONED WESTERN CONUS PARENT TROUGH/CLOSED LOW. GIVEN THAT SKIES SHOULD GENERALLY AVERAGE PARTLY CLOUDY OVERNIGHT...ESPECIALLY WEST...AM NOT ANTICIPATING IDEAL RADIATIONAL COOLING CONDITIONS DESPITE THE CONTINUED PRESENCE OF THE LOW LEVEL RIDGE AXIS SITTING DIRECTLY OVER THE AREA...WHICH WILL RESULT IN SEVERAL HOURS OF GENERALLY LIGHT/VARIABLE TO EASTERLY BREEZES. FOR LOW TEMPS...SLIGHTLY UNDERCUT A BLEND OF 12Z MET/MAV GUIDANCE...WHICH RESULTS IN THE MAJORITY OF THE AREA BOTTOMING OUT BETWEEN 38-43...AND MAYBE DOWN AROUND 36 IN THE COLDER-PRONE WESTERN DAWSON COUNTY AREA. THAT BEING SAID...IF SKIES AVERAGE CLEARER THAN ANTICIPATED...COULD SEE MORE OF THE CWA MAKE A RUN TOWARD THE MID 30S...AND THIS WILL NEED WATCHED IN CASE A FEW SPOTS FLIRT WITH FROST-WORTHY READINGS. FOR NOW...HAVE LEFT OUT FROST MENTION ALL AREAS. HOWEVER...HAVE LEFT IN A MENTION OF PATCHY FOG CWA-WIDE FROM 09Z-13Z AS THE LIGHT WIND REGIME COULD PROMOTE SOME DEVELOPMENT. THIS WOULD GENERALLY SEEM MOST FAVORED WITHIN THE EASTERN 1/2 OF THE CWA IN CLOSEST PROXIMITY TO THE WEST EDGE OF LOWER STRATUS...AND ALSO OVER WHERE A BIT MORE LIGHT PRECIP FELL DURING THE PAST FEW DAYS. FOR NOW...AM NOT EXPECTING SIGNIFICANT VISIBILITY ISSUES...BUT ITS WORTH NOTING THAT THE LATEST HRRR ACTUALLY DOES SUGGEST SOME DENSER FOG DEVELOPMENT MAINLY EAST OF HIGHWAY 281...SO THIS ALSO BEARS WATCHING. TURNING TO THE DAYTIME HOURS MONDAY...THE OVERALL MID/UPPER AIR PATTERN CHANGES LITTLE...AS THE CENTRAL PLAINS REMAIN UNDER FAIRLY UNEVENTFUL QUASI-ZONAL FLOW ALOFT...AND STILL DOWNSTREAM FROM A LEAD SHORTWAVE EJECTING NORTHEAST TOWARD THE REGION FROM THE DESERT SOUTHWEST...WHICH COULD PROMOTE SOME RAIN CHANCES MONDAY NIGHT AS DESCRIBED BELOW. IN ADDITION...JUST TO THE NORTH THE COMPACT LITTLE CLOSED LOW OVER SD SHOULD PRETTY MUCH REMAIN IN PLACE...WITH LITTLE CONSEQUENCE INTO NEB/KS. AT THE SURFACE...THE RIDGE AXIS WILL ONLY SLOWLY EDGE EAST DURING THE DAY...PROVIDING A DAY OF FAIRLY LIGHT BREEZES. EVEN DURING THE AFTERNOON...THE EASTERN 1/2 OF THE CWA WILL ONLY AVERAGE AROUND 5 MPH...WHILE WESTERN COUNTIES PICK UP A SLIGHTLY STRONGER EAST-SOUTHEAST BREEZE OF 10 TO POSSIBLY 15 MPH. ASSUMING THAT SKIES AVERAGE MOSTLY CLEAR/PARTLY CLOUDY UNDER ONLY PASSING MID-HIGH CLOUDS...SHOULD SEE A NICE JUMP IN HIGH TEMPS VERSUS TODAY...AND MADE LITTLE CHANGE TO PREVIOUS FORECAST WITH ALL AREAS RISING TO WITHIN A FEW DEGREES EITHER SIDE OF 70. THE ONLY CAVEAT FOR THESE WARM TEMPS WOULD BE IF ANY MORNING FOG TURNS INTO A SLOW-ERODING STRATUS DECK THAT LINGERS WELL INTO THE DAY WITHIN THE RIDGE AXIS MAINLY IN THE EASTERN CWA...BUT IT SEEMS UNLIKELY THAT THE SITUATION GETS THIS PESSIMISTIC. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 345 PM CDT SUN MAY 5 2013 A PROLONGED PERIOD OF UNSETTLED WEATHER IS SHAPING UP ACROSS THE REGION AS THE UPPER LEVEL LOW OFF THE CALIFORNIA COAST SLOWLY PROGRESSES EASTWARD WHILE SPINNING OFF SEVERAL WEAK DISTURBANCES AHEAD OF IT. WHILE A GENERALLY BLOCKY PATTERN WITH RIDGING WILL EXIST ACROSS THE CENTRAL PLAINS THROUGH MUCH OF THE PERIOD...THE LOW LEVEL FLOW WILL BEGIN TO SHIFT AND BECOME SOUTHERLY LATE MONDAY...HELPING MOISTURE ADVECT NORTHWARD. THIS FLOW SHOULD HELP DEWPOINTS CLIMB BACK INTO THE 50S BY TUESDAY AFTERNOON...WITH BUILDING INSTABILITY ACROSS THE PLAINS. WHILE INITIALLY...THERE WILL BE A SMALL CHANCE FOR SOME RAIN SHOWERS AHEAD OF THE FIRST UPPER LEVEL WAVE SPINNING OFF THE WESTERN LOW...INSTABILITY WILL BE VERY WEAK...AND LOW LEVEL MOISTURE WILL STILL BE LACKING...IN ORDER TO SUPPORT MUCH IN THE WAY OF SHOWER OR THUNDERSTORM ACTIVITY. AS A RESULT...SLOWED DOWN THE INITIAL TIMING OF THE ONSET OF ANY PRECIPITATION TO THE PRE-DAWN HOURS TUESDAY. AS MOISTURE CONTINUES TO SURGE NORTH DURING THE DAY TUESDAY AFTERNOON...INSTABILITY WILL BUILD...AND SEE THE POTENTIAL FOR SOME THUNDERSTORMS TO DEVELOP DURING THE LATE MORNING/EARLY AFTERNOON HOURS AS STEEP LOW LEVEL LAPSE RATES WILL REQUIRE LITTLE IN THE WAY OF FORCING FOR SHOWER AND THUNDERSTORM DEVELOPMENT. AS WE THEN TRANSITION INTO TUESDAY NIGHT...THE NOSE OF THE LOW LEVEL JET IS EXPECTED TO BE POINTED TOWARDS THE LOCAL AREA...WHICH SHOULD ALLOW FOR THE DEVELOPMENT OF ELEVATED CONVECTION ACROSS THE LOCAL AREA DURING THE LATE EVENING AND OVERNIGHT HOURS...SOME OF WHICH COULD BECOME STRONG TO MARGINALLY SEVERE. AS A RESULT...PLAN ON HIGHLIGHTING THE POTENTIAL FOR SOME MARGINALLY SEVERE HAIL FOR THE TUESDAY NIGHT PERIOD IN THE AFTERNOON HWO. BEYOND TUESDAY NIGHT...THINGS GET A LITTLE MORE MUDDLED AS MULTIPLE WEAK DISTURBANCES AHEAD OF THE MAIN UPPER LEVEL LOW TRANSITION ACROSS THE PLAINS. EVEN SO...THERE IS SOME AGREEMENT AMONGST THE MODELS FOR ANOTHER DECENT SHOT OF PRECIPITATION ACROSS NORTH CENTRAL KANSAS AND PORTIONS OF SOUTH CENTRAL NEBRASKA WEDNESDAY NIGHT AND THURSDAY...AND SAW NO REASON TO REDUCE THE LIKELY POPS GIVEN BY THE ALLBLEND SOLUTION FOR THIS PERIOD. THEN...DEPENDING ON WHICH MODEL SOLUTION YOU BELIEVE...THE MAIN UPPER LEVEL LOW SHOULD BEGIN TO TRACK EASTWARD ON FRIDAY...WITH A COLD FRONT DROPPING DOWN ACROSS THE NORTHERN PLAINS FRIDAY NIGHT OR SATURDAY. DUE TO THE DISCREPANCIES IN TIMING...HUNG ONTO CHANCES FOR PRECIPITATION THROUGH SATURDAY AFTERNOON...WITH PRECIPITATION COMING TO AN END BEHIND THIS COLD FRONT BY THE LATTER HALF OF NEXT WEEKEND. WHILE THERE WILL BE A NOTICEABLE DROP IN TEMPERATURES BEHIND THIS FRONT...ON THE ORDER OF 10-15F BASED ON 850MB TEMPS...DO NOT EXPECT A RETURN TO THE CHILLY TEMPERATURES OF LATE...AS ABOVE NORMAL TEMPERATURES ARE EXPECTED ALL WEEK...GENERALLY IN THE LOWER TO MIDDLE 70S...WITH THIS NEXT FRONT SIMPLY DROPPING TEMPERATURES A FEW DEGREES BELOW CLIMATOLOGY FOR EARLY/MID MAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1229 AM CDT MON MAY 6 2013 VFR CONDITIONS EXPECTED THROUGH MUCH OF THE TAF PERIOD...ALTHOUGH IFR CONDITIONS WILL BE POSSIBLE 10-14Z. SCATTERED MID TO HIGH LEVEL CLOUDS WILL CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS. THE PRESENCE OF A SURFACE RIDGE WILL KEEP THE SURFACE WIND LIGHT AND VARIABLE THROUGH TONIGHT...BEFORE BECOMING MORE ESTABLISHED FROM THE SOUTHEAST DURING THE DAY MONDAY. A DECREASING LOW LEVEL DEWPOINT DEPRESSION...WORKING IN CONCERT WITH THE AFOREMENTIONED LIGHT SURFACE WIND...MAY PROMOTE FOG DEVELOPMENT AT KGRI BETWEEN 10Z AND 14Z THIS MORNING. CONFIDENCE OF SUCH VISIBILITY RESTRICTION ACTUALLY OCCURRING IS ABOUT 50%...WITH THE SITUATION LIKELY BECOMING MORE CLEAR BETWEEN 10Z AND 12Z. FOR NOW WILL GO WITH A PREVAILING IFR VISIBILITY AND AN MVFR CEILING...PER GUIDANCE...10-14Z AND IF NECESSARY...UPDATE AS WE APPROACH SUNRISE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...SAR AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
703 PM EDT MON MAY 6 2013 .SYNOPSIS... HIGH PRESSURE OVER THE NORTHEAST REGION OF THE COUNTRY WILL KEEP NICE WEATHER OVER THE NORTH COUNTRY INTO THE FIRST HALF OF WEDNESDAY. FOR THE SECOND HALF OF WEDNESDAY...LOW PRESSURE OVER THE OHIO VALLEY WILL LIFT SLOWLY NORTHEAST TOWARDS THE AREA. THIS WILL BRING LIGHT PRECIPITATION LATE WEDNESDAY INTO FRIDAY. A FRONTAL BOUNDARY WILL TRAVERSE THE AREA FOR THE UPCOMING WEEKEND PROVIDING THE CHANCE FOR MORE LIGHT PRECIPITATION. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 703 PM EDT MONDAY...PERSISTENCE FORECAST CONTINUES TO BE THE GENERAL THEME FOR THIS EVENING. HIGH PRESSURE CONTINUES TO REMAIN IN CONTROL WITH SOUTH/SOUTHEAST SFC WINDS AND CLEAR SKIES. SIMILAR TO PREVIOUS NIGHTS...NOTICED SEVERAL BUFKIT FORECAST SOUNDINGS SHOWING A NOCTURNAL LOW-LEVEL JET OF SORTS AROUND 25 KTS OR SO JUST OFF THE DECK IN THE CHAMPLAIN VALLEY. THIS KEPT SOUTHERLY WINDS GOING LAST NIGHT IN THE CHAMPLAIN VALLEY...AND WITH LITTLE CHANGE BETWEEN YESTERDAY AND TODAY HAVE OPTED TO BUMP UP WINDS A BIT IN THE CHAMPLAIN VALLEY AREA. HAVE ALSO TWEAKED DEWPOINTS DOWNWARD. CURRENT FORECAST AND VAST MAJORITY OF GUIDANCE SHOWED HIGHER DEWPOINTS THAN REALITY. HAVE BLENDED MORE OF THE BIAS- CORRECTED RAP DEWPOINTS WHICH ACTUALLY ARE RUNNING TOO DRY TO BETTER SHOW THE LOWER DEWPOINTS. THESE WILL EVENTUALLY CLIMB BACK UP SOME AFTER MIDNIGHT THIS EVENING. NO CHANGES TO TEMPERATURES...WHICH WILL FALL QUICKLY ONCE AGAIN ESPECIALLY AFTER SUNSET. TEMPERATURES MAY STAY UP INTO THE 50S IN THE CHAMPLAIN VALLEY DUE TO THE JET...BUT LOWS IN THE MID/UPPER 30S FOR THE CUSTOMARY COOLER DACKS/NORTHEAST VERMONT AREAS TO THE 40S FOR THE REST OF THE NORTH COUNTRY. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 320 PM EDT MONDAY...GOING INTO TUESDAY...THE ENTIRE FORECAST AREA WILL SEE ANOTHER REPEAT OF WX REGIME GOING ON TODAY. RIDGE IN PLACE OFF THE NEW ENGLAND COAST FOR ANOTHER DAY. GOING FOR HIGHS AGAIN IN THE M/U70S IN MOST SPOTS WITH SOME CVLY/SLV LOCALES NEAR 80F TO L80S. FOR TUESDAY NIGHT...SOME MID/HIGH CLDS FROM LOW OVER OHIO VALLEY WILL WORK INTO SOUTHERN VERMONT AFT 06Z...OTHERWISE CLR SKIES ABOUND. FIRST HALF OF WEDNESDAY WILL SEE SFC RIDGE FINALLY BEGIN TO BREAK DOWN AND SHIFT OFFSHORE AS LOW FROM OHIO VALLEY SHIFTS SLOWLY INTO THE MID-ATLANTIC REGION. WILL HOLD OFF ON PRECIP FOR MUCH OF THE CWA UNTIL EARLY AFTNOON WHEN LIGHT -RW WORK INTO SC VT...THEN OVERSPREAD CWA THRU THE OVERNGT HRS WED. DRY AIRMASS/SUBSIDENCE LEFT BEHIND FROM EXITING RIDGE...WILL ALLOW MANY SPOTS TO STAY DRY UNTIL AIRMASS BECM SATURATED ENOUGH TO PRODUCE RAIN. OVERALL QPF NEAR A TENTH OF AN INCH AT MOST THRU WED NGT. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 425 PM EDT MONDAY...UNSETTLED WEATHER EXPECTED THROUGH THE PERIOD WITH A CHANCE OF RAIN SHOWERS AND COOLER TEMPERATURES. THE CLOSED UPPER LOW CURRENTLY OVER THE SOUTHEASTERN U.S. WILL BE OVER EASTERN PENNSYLVANIA EARLY THURSDAY. THIS UPPER LOW WILL MOVE NORTHEAST INTO THE GULF OF MAINE BY THURSDAY NIGHT. THIS UPPER LOW WILL BRING A CHANCE OF RAIN SHOWERS TO THE NORTH COUNTRY THURSDAY AND FRIDAY. A COLD FRONT WILL MOVE SOUTH INTO THE REGION FROM CANADA ON FRIDAY AND WILL BRING MORE RAIN SHOWERS TO THE REGION FRIDAY AND FRIDAY NIGHT. A WARM FRONT WILL APPROACH THE REGION ON SATURDAY BRINGING ANOTHER CHANCE FOR RAIN SHOWERS TO THE NORTH COUNTRY. A STRONG COLD FRONT WILL MOVE SOUTHEAST FROM CANADA ON SUNDAY AND WILL BRING MORE RAIN SHOWERS ALONG WITH MUCH COOLER AIR. ON MONDAY... ECMWF AND GFS MODELS IN GOOD AGREEMENT IN BRINGING A CLOSED UPPER LOW THROUGH THE REGION ON MONDAY. 500 MB TEMPERATURES BY MONDAY AFTERNOON WILL BE -30C TO -35C. HIGH TEMPERATURES ON MONDAY WILL ONLY BE IN THE 50S...WITH SOME 40S OVER THE HIGHER ELEVATIONS OF THE ADIRONDACKS AND GREEN MOUNTAINS. HAVE GONE WITH A 30 PERCENT CHANCE OF SHOWERS FOR MONDAY. GIVEN THE STRONG COLD POOL OF AIR ALOFT AT 500 MB...WOULD NOT BE SURPRISED TO SEE SMALL HAIL MONDAY AFTERNOON ALONG WITH AN ISOLATED LOW TOP THUNDERSTORM OR TWO. GIVEN THAT THIS IS 7 DAYS OUT HAVE NOT INCLUDED THIS IN THE GRIDS AT THIS TIME. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THROUGH 00Z WEDNESDAY...VFR TO CONTINUE THROUGH THE PERIOD WITH LIGHT SOUTH WINDS FOR THIS EVENING. THE EXCEPTION REGARDING WINDS WOULD BE TONIGHT AT BTV WHERE PRESENCE OF A LOW-LEVEL JET MAY LEAD TO STRONGER SOUTH WINDS /AROUND 09-12KTS/...AND THEN DURING THE LATE MORNING/EARLY AFTERNOON TUESDAY DUE TO LAKE BREEZE INFLUENCE AT PBG AND BTV. EXPECT SOME DIURNAL FAIR WEATHER CUMULUS TO DEVELOP AT SLK WITH BASES AROUND 6KFT BUT THE REST OF THE TAFS WILL BE SKC. OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...VFR CONDITIONS EXPECTED TO CONTINUE TUESDAY AND WEDNESDAY AS A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT REMAINS OVER THE REGION. A CLOSED UPPER LOW OVER THE MID ATLANTIC STATES EARLY WEDNESDAY NIGHT WILL MOVE NORTHEAST AND BRING A CHANCE OF RAIN SHOWERS TO THE REGION WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...WITH SOME MVFR CONDITIONS POSSIBLE IN RAIN SHOWERS. A COLD FRONT WILL MOVE INTO THE REGION ON FRIDAY AND THEN BECOME NEARLY STATIONARY...WITH A CHANCE OF RAIN SHOWERS FRIDAY AND SATURDAY...WITH SOME AREAS OF MVFR POSSIBLE. && .FIRE WEATHER... HIGH PRESSURE OVERHEAD WILL KEEP PRECIP OUT OF THE NORTH COUNTRY...WITH FULL SUN EXPECTED DURING THE DAY AND RELATIVE HUMIDITY VALUES FALLING TO 15-25 PERCENT THROUGH TUESDAY. THUS THE EXTENDED PERIOD OF DRY WEATHER WILL CONTINUE WITH ABOVE NORMAL TEMPERATURES IN THE 70S TO AROUND 80 DURING THE DAY AND 40S TO LOW 50S AT NIGHT. HAVE MENTIONED THE CONCERNS OF THE VERMONT DEPARTMENT OF FORESTS...PARKS AND RECREATION REGARDING OPEN BURNING IN SUCH DRY CONDITIONS IN OUR HAZARDOUS WEATHER OUTLOOK. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JN NEAR TERM...JN/LOCONTO SHORT TERM...JN LONG TERM...WGH AVIATION...WGH/LOCONTO FIRE WEATHER...WFO BTV
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
314 AM EDT MON MAY 6 2013 .SYNOPSIS... A VERY SLOW MOVING STORM SYSTEM WILL BRING SOME RAIN TODAY AND THEN MORE SCATTERED SHOWERY WEATHER ON TUESDAY. A LATE WEEK WARMUP WILL PRECEDE A COLD FRONT THAT MAY ARRIVE ON SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM MONDAY...SHOWERS WERE ONGOING ACROSS THE FORECAST AREA THIS MORNING. COVERAGE WAS NUMEROUS. A LARGE BATCH OF SHOWERS AND THUNDERSTORMS WAS OFFSHORE IN ASSOCIATION WITH AN AREA OF LOW PRESSURE. A COASTAL TROUGH LIED RIGHT ALONG THE IMMEDIATE COAST. AN OCCLUDED FRONT WAS JUST UPSTREAM OF THE PEE DEE. THE OCCLUDED FRONT WILL MOVE FROM SW TO NE ACROSS THE FORECAST AREA...LASTLY ACROSS THE CAPE FEAR AREA DURING THE EVE. MUCH DRIER AIR WILL MOVE INTO THE AREA BEHIND THIS FRONT. WILL MAINTAIN HIGH POPS...GENERALLY LIKELY TO CATEGORICAL...UNTIL THIS BOUNDARY LIFTS OUT AND AWAY FROM THE AREA. WILL CONTINUE TO CHARACTERIZE THE PRECIPITATION AS SHOWERS...SOME OF WHICH COULD PRODUCE HEAVY DOWNPOURS FROM TIME TO TIME. ADDITIONAL RAINFALL AMOUNTS OF ONE-HALF TO THREE-QUARTERS OF AN INCH ARE EXPECTED BEFORE THE SHOWERS SHUT OFF. POPS WILL BE TRENDING LOWER THIS MORNING ACROSS OUR SOUTHWEST ZONES AND WILL NOT CARRY MENTION OF SHOWERS THERE THIS AFTERNOON. HOWEVER...ACROSS THE REMAINDER OF THE AREA...ALTHOUGH POPS WILL BE TRENDING LOWER...DO EXPECT ISOLATED TO SCATTERED SHOWERS TO REMAIN IN THE PICTURE...EVEN THIS AFTERNOON...ALONG AND N OF A LINE FROM UDG TO CRE WHERE THE DEEPER MOISTURE WILL HANG ON LONGEST. ALSO WATCHING SOME STRATUS AND FOG THAT HAS DEVELOPED TO OUR SOUTH WHICH MAY ADVECT INTO OUR SOUTHERN ZONES FOR A TIME THIS MORNING... BEFORE THE ARRIVAL OF DRIER AIR HELPS IN THE DISSIPATION PROCESS. A BROAD AND SLOW MOVING...VERTICALLY STACKED AREA OF LOW PRESSURE... CENTERED ACROSS THE TENNESSEE VALLEY THIS MORNING...WILL CONTINUE TO DRIFT TOWARD THE EASTERN CAROLINAS WITH THE EASTERN FRINGES OF THIS FEATURE BEGINNING TO MOVE INTO THE AREA TONIGHT. WILL REINTRODUCE POPS INTO SW AND W AREAS TONIGHT WHILE ANY RESIDUAL SHOWERS ASSOCIATED WITH THE OCCLUDED FRONT LIFT N AND NE OF THE AREA. CLOUD COVER WILL TEND TO THIN LATER THIS MORNING AND THROUGH THE AFTERNOON...ESPECIALLY ACROSS S AND SW AREAS WHERE CONSIDERABLE BREAKS OF SUNSHINE SHOULD DEVELOP. THIS WILL ALLOW TEMPS TO REACH THE LOWER TO MID 70S...HIGHEST ACROSS PORTIONS OF THE PEE DEE... AND COOLEST N OF A LBT TO ILM LINE...WHERE CLOUDS WILL REMAIN THICKEST LONGEST. ALSO TEMPS WILL BE HELD DOWN THIS AFTERNOON ALONG THE COAST...ESPECIALLY ACROSS COASTAL BRUNSWICK AND SOUTHERN NEW HANOVER COUNTIES DUE TO AN ONSHORE WIND. COOLER AIR WILL BE ARRIVING IN ASSOCIATION WITH THE UPPER LOW TONIGHT...FIRST ACROSS WESTERN ZONES. CLOUDS SHOULD BE ON THE INCREASE AS THIS FEATURE DRAWS VERY SLOWLY CLOSER. STILL...TEMPS WILL BE CONSIDERABLY COOLER THAN SUN NIGHT...WITH LOWS EXPECTED TO REACH THE LOWER TO MID 50S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...CLIMATOLOGICALLY UNUSUAL UPPER LEVEL CUTOFF AND COLD POOL OVER THE AREA ON TUESDAY MAKING FOR A TRICKY FORECAST. THE MAIN AXIS OF DEEP MOISTURE AND LIFT WILL HAVE ALREADY LIFTED TO THE NORTH BY THE START OF THE PERIOD. THE SYNOPTIC SCALE DRYSLOT WILL ALSO HAVE PUSHED THROUGH IN THE LOWER LEVELS BUT THE SWIRLING MASS OF MID LEVEL MOISTURE AND COLD AIR WILL STILL BE OVERHEAD. TUESDAY THUS SHAPING UP TO BE VARIABLY CLOUDY WITH POCKETS OF SUN LEADING TO STEEP LL LAPSE RATES AND CU FIELDS. THESE CONVECTIVE ELEMENTS WILL HAVE SOME MID LEVEL INSTABILITY TO GROW INTO SHOWERS WITH EVEN A FEW RUMBLES OF THUNDER. HOWEVER THE SUBCLOUD LAYER IS FORECAST TO BE VERY DRY. COVERAGE THUS CAPPED AT SCT/CHC RANGE. BREAKS IN CLOUDS SHOULD BE COMMON ENOUGH IN MOST PLACES FOR LOW 70S FOR A HIGH. WHATEVER EXTENT SHOWER ACTIVITY MANAGES TO MANIFEST WILL ALL BE GONE BY SUNSET. WRAPAROUND MOISTURE WILL MEAN CLOUDS SLOW TO DECREASE TUESDAY NIGHT AND EARLY WEDNESDAY BUT A MORE RAPID DRYING TREND SLATED FOR LATER WED AFTERNOON. THIS WILL MANAGE TO BOLSTER HIGHS A FEW DEGREES TO MID / UPPER 70S N TO S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...MUCH OF THE LONG TERM WILL BRING A RETURN OF CLIMATOLOGICAL TEMPERATURES. THE EXIT OF THE LOW PRESSURE SYSTEM OF THE SHORT TERM WILL ALLOW FOR A LOW AMPLITUDE RIDGE TO BUILD OVER THE SOUTHEASTERN U.S. SURFACE PRESSURE PATTERN WILL BE RATHER WEAK WHICH SHOULD PREVENT ADEQUATE MOISTURE TO SUPPORT ANY MEANINGFUL PRECIP CHANCES EVEN AS AFTERNOON SEA BREEZE DEVELOPS EACH DAY. FRIDAY INTO SATURDAY A DEEP TROUGH WILL BE GETTING CARVED INTO THE GREAT LAKES REGION. LEADING EDGE OF THIS SYSTEM WILL BE A FAIRLY SHARP COLD FRONT. THIS MAY BE DUE THIS FAR SOUTH ON SUNDAY. MOISTURE FLUX MAY OCCUR LONG ENOUGH SAT INTO SUNDAY FOR SUFFICIENT MOISTENING FOR GOOD RAIN CHANCES ONCE THE FRONT ARRIVES. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...TRICKY FORECAST CONTINUES AS UNSETTLED WEATHER BRINGS PERIODS OF MVFR AND IFR DUE TO VARYING LOW CIGS...AREAS OF FOG...AND RAIN SHOWERS...ESPECIALLY THROUGH THIS MORNING. OTHERWISE EXPECT VFR. VARYING CEILINGS AND VISIBILITIES IN SHOWERS AND BR THROUGH THIS MORNING. CONFIDENCE IS A BIT LOW GIVEN THE VARYING RAINFALL RATES. ALSO SOME CONCERN THAT FOG WILL ADVECT INTO PORTIONS OF THE AREA FROM THE SOUTH AS DEWPOINTS CONTINUE TO CLIMB INTO THE 60S. PERIODS OF HEAVIER RAINFALL WILL LIKELY CREATE BRIEF PERIODS OF IFR. AS DRIER AIR REACHES THE AREA LATER THIS MORNING AND THROUGH THE AFTERNOON...EXPECT VFR CONDITIONS TO DEVELOP AS CEILINGS AND LOWER VISIBILITIES IMPROVE AND THE RISK FOR SHOWERS DIMINISHES. SOUTHEAST WINDS AOB 12 KTS WILL GRADUALLY BECOME SOUTH IN THE AFTERNOON. TOWARDS THE END OF THE PERIOD...LIGHT WINDS AND VFR WILL PREVAIL. EXTENDED OUTLOOK...AN UPPER LOW WILL MOVE OVER THE AREA TUESDAY WITH SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EVENING. SMALL HAIL WILL BE POSSIBLE WITH UNUSUALLY LOW FREEZING LEVELS. AN ISOLATED SHOWER IS POSSIBLE WEDNESDAY AFTERNOON. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1115 PM SUNDAY...LATEST SFC PRESSURE PATTERN AND GRADIENT AHEAD OF THE APPROACHING BOUNDARY FROM THE SOUTH...CONTINUE TO SUPPORT EAST TO SOUTHEAST 15 TO 25 KT WINDS...WITH FEW GUSTS UP TO 30 KT. CURRENTLY THIS FRONT IS IN THE VICINITY OF CAPE ROMAIN SC...VIA LATEST SFC OBS. HRRR MODEL DATA SUPPORTS ITS SLOW PROGRESSION NORTHWARD OVERNIGHT INTO MONDAY. THE ILM SC WATERS WILL LIKELY SEE WINDS VEERING TO THE S OR SSW 10 TO 15 KT AFTER ITS PASSAGE DURING THE PRE-DAWN HRS OF MONDAY. IT MAY TAKE UP TO THE EARLY AFTERNOON HOURS OF MONDAY BEFORE PUSHING ACROSS AND NORTH OF THE ILM NC WATERS...THIS BASED ON LATEST NAM AND GFS MODEL OUTPUT. SIGNIFICANT SEAS WILL CONTINUE TO BE DOMINATED BY A PSEUDO NE-E DIRECTION SWELL AT 7 TO 8 SECOND DOMINANT PERIODS. OVERALL...SIG SEAS WILL RANGE BETWEEN 4 AND 8 FT...HIGHEST OUTER WATERS OFF CAPE FEAR AND WINYAH BAY...AND LOWEST SOUTH OF CAPE FEAR TO LITTLE RIVER INLET. AS WINDS SUBSIDE AFTER THE PASSAGE OF THE FRONTAL BOUNDARY...THE IMMEDIATE WIND DRIVEN WAVES WILL BEGIN TO SUBSIDE. HOWEVER...WAVEWATCH3 INDICATES A NE 10-11 SECOND PERIOD SWELL TO LITERALLY OCCUPY A LARGE CHUNK OF THE NORTH ATLANTIC BASIN. LATEST WAVEWATCH3 DOES INDICATE A SLOWER SUBSIDING TREND...WHEREAS THE LOCALLY PRODUCED SWAN IS A BIT TOO QUICK. PREFER THE SLOWER TREND. AS A RESULT...HAVE CONTINUED THE SCA MAINLY FOR SIG SEAS THRU MIDDAY MONDAY ACROSS THE ILM SC WATERS...AND LATE AFTERNOON MONDAY FOR THE ILM NC WATERS. OVERALL...AVERAGE PERIODS WILL RUN 5.5 SECONDS. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...WITH SUCH A CIRCULAR LOW BOTH AT THE SURFACE AND ALOFT MOVING OVER THE REGION WINDS WILL BE QUITE LIGHT ON TUESDAY BUT ALSO SHOW CONSIDERABLE VARIATION IN DIRECTION ESPECIALLY EARLY. AS THE LOW PULLS AWAY LATE IN THE DAY A PREDOMINANT SW FLOW MAY GET ESTABLISHED. THE EXIT OF THE SYSTEM TO THE NORTHEAST WILL BE SO GRADUAL THAT SW WINDS WILL PERSIST TROUGH THE PERIOD. A SLIGHTLY HIGHER WIND SPEED WILL BE EXPERIENCED ON WEDNESDAY AS THE EXIT OF THE SURFACE WAVE ALLOWS FOR A SLIGHTLY STRONGER GRADIENT ACROSS THE WATERS. IN THE ABSENCE OF ANY SWELL ENERGY SEAS WILL BE PREDOMINANTLY WIND WAVES THROUGH THE PERIOD. AS SUCH DOMINANT WAVE HEIGHT WILL BE CAPPED AT 3 FT THROUGH THE SHORT TERM. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...QUIET MARINE CONDITIONS EXPECTED FOR THE LONG TERM PERIOD. THE SURFACE PRESSURE PATTERN WILL BE RATHER POORLY DEFINED FOR MOST OF IT AS THE NEAREST `PLAYER` WILL BE WEAK HIGH PRESSURE IN THE ATLANTIC BUT NOT NEAR BERMUDA AS IT OFTEN THE CASE BUT MUCH REMOVED FURTHER EASTWARD. SEAS ON THE ORDER OF 2 TO 3 FT WILL BE COMPRISED OF A 5 SECOND WIND CHOP AND A 7-8 SECOND WEAK SE SWELL. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR AMZ250- 252. && $$ SYNOPSIS...MBB NEAR TERM...RJD SHORT TERM...MBB LONG TERM...MBB AVIATION...RJD/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
158 AM EDT MON MAY 6 2013 .SYNOPSIS... A SLOW MOVING AND COMPLEX STORM SYSTEM WILL CROSS THE CAROLINAS OVER THE NEXT FEW DAYS. SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE INTO MONDAY MORNING...THEN AGAIN ON TUESDAY. WIDESPREAD RAINFALL IS EXPECTED. WEAK HIGH PRESSURE WILL SLOWLY FILL IN BEHIND THE DEPARTING STORM WEDNESDAY AND THURSDAY. MUCH WARMER TEMPERATURES ARE EXPECTED LATE IN THE WEEK AS THE REGION DRIES OUT. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 11 PM SUNDAY...MAIN FOCUS OF THIS UPDATE REMAINS WITH THE REDISTRIBUTION OF OVERNIGHT POPS. FOR LATE THIS EVENING... BASICALLY TOOK THE CURRENT 88D MOSAIC AND EXTRAPOLATED THE MOVEMENT FOR THE NEXT 3 HRS. AFTERWARD...THE LATEST NAM AND HRRR MODELS WERE UTILIZED FOR THE REMAINDER OF THE PRE-DAWN HOURS. IN ESSENCE...THE MAIN CONVEYOR BELT OF PCPN OVER THE ATL WATERS...IS CURRENTLY AND SLOWLY LIFTING NE WARD. THE PCPN WITHIN THIS BELT IS MOVING FROM SSE TO NNW...AND PUSHING ONSHORE. AFTER THE PCPN MOVES ONSHORE...ITS AREAL COVERAGE DECREASES FROM WIDESPREAD/AREAS OVER THE ADJACENT ATL WATERS TO SCATTERED OVER LAND AREAS. OF NOTE...DRIER AIR...VIA LATEST WATER VAPOR LOOPS...IS PARTIALLY FILTERING IN FROM THE SOUTH AND LIKELY HAVING SOME INPUT FOR WHY PCPN IS NOT AS WIDESPREAD AND/OR INTENSE OVER LAND. IN GENERAL WILL INDICATE CATEGORICAL POPS CLOSER TO THE COAST...SLIGHTLY DROPPING THE FURTHER INLAND ONE GOES. QPF HAS ALSO BEEN FURTHER TWEAKED TO ACCOUNT FOR THE LACK OF WIDESPREAD/ INTENSE PCPN COVERAGE. LATEST MIN TEMPS WERE TWEAKED TO THE HIER SIDE OF GUIDANCE WITH AROUND 60 INLAND...TO 60-65 AT THE COAST. HOURLY SFC DEWPOINTS WILL MIMIC HOURLY TEMPS...EXCEPT LOWER BY 1 TO 3 DEGREES DUE TO THE INFLUX OF MOISTURE AND MILD TEMPS UNDER THE E TO SE FLOW. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...AN OCCLUDED FRONT BENT BACK TO THE NORTHWEST WILL SWING THROUGH THE EASTERN CAROLINAS MONDAY MORNING ACCOMPANIED BY A BAND OF MODERATE OR POSSIBLY HEAVY SHOWERS. FOR EASTERN SC THE BULK OF THE RAIN SHOULD BE DONE BY SUNRISE...BUT IT WILL PROBABLY TAKE AT LEAST A FEW MORE HOURS FOR RAIN TO CLEAR ELIZABETHTOWN AND BURGAW. BEHIND THIS FRONT A DRIER AIRMASS WILL BUILD IN DURING THE DAY ON SOUTH WINDS. (YES...IT HAS BEEN THAT KIND OF SPRING) THE MONSTER UPPER LOW THAT HAS MOVED ACROSS THE SOUTHEAST THE PAST COUPLE OF DAYS WILL DRAW NEAR ENOUGH TO THE REGION DURING THE AFTERNOON TO STEEPEN LAPSE RATES FROM 750 MB UP THROUGH THE TROPOPAUSE. EVEN WITH LIMITED MOISTURE...WARMING DAYTIME TEMPERATURES COULD PRODUCE A FEW POP-UP SHOWERS...ENOUGH TO WARRANT A SMALL POP DURING THE AFTERNOON. PARTLY CLOUDY TO MOSTLY CLEAR SKIES MONDAY EVENING AND LIGHT WINDS WILL ALLOW TEMPERATURES TO FALL SURPRISINGLY FAST AND LOWS SHOULD REACH 50-55 BY 3 AM. CLOUDS SHOULD INCREASE LATE MONDAY NIGHT AS THE CIRCULATION OF THE UPPER LOW MOVES ACROSS SOUTH CAROLINA AND WE COULD HAVE SHOWERS REDEVELOPING BY DAYBREAK TUESDAY... ESPECIALLY ACROSS THE SC PEE DEE REGION. TUESDAY WILL BE A VERY INTERESTING DAY METEOROLOGICALLY. VERY COLD MID AND UPPER LEVEL TEMPERATURES FOR THE SEASON WILL PUSH OVERHEAD DURING THE PEAK OF SOLAR HEATING. FREEZING LEVELS WILL PLUNGE TO ONLY 8000 FEET...700 MB TEMPS FALL TO -4C...AND 500 MB TEMPS SHOULD GO AS LOW AS -22C. MODEL FORECAST SOUNDINGS HAVE CONVECTIVE TEMPERATURES AS LOW AS 63-67 DEGREES...SEVERAL DEGREES BELOW MY FORECAST HIGHS. THE LIMITING FACTORS WILL BE SUNSHINE AND LOW LEVEL MOISTURE AS SURFACE DEWPOINTS WILL HOLD IN THE 49-53 RANGE. EVEN GIVEN THESE LIMITATIONS I ANTICIPATE WIDESPREAD TOWERING CUMULUS DEVELOPMENT WITH 50-70 PERCENT COVERAGE OF SHOWERS DURING THE DAY. RELATIVELY WEAK UPDRAFT STRENGTH (LIFTED INDEX NO GREATER THAN -2 AT ANY PRESSURE LEVEL) AND NO STORM ORGANIZATION (0-6 KM BULK SHEAR <20 KT) SHOULD PRECLUDE LARGE HAIL...BUT SMALL HAIL IS POSSIBLE GIVEN THE HIGH PROPORTION OF CAPE WITHIN THE -10C TO -30C REGION AND THE SMALL DISTANCE BETWEEN THE ENVIRONMENTAL FREEZING LEVEL AND THE GROUND. THE ATMOSPHERE SHOULD STABILIZE TUESDAY NIGHT AS THE UPPER LOW DRIFTS JUST NORTH OF THE REGION. A FEW LINGERING SHOWERS MAY CARRY ON INTO THE EVENING HOURS BUT THE TREND SHOULD BE FOR DRYING CONDITIONS WITH LOWS IN THE LOWER 50S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE NORTHEAST THROUGH THE CAROLINAS TOWARD THE MID ATLANTIC COAST WED THROUGH THURS. THE H5 LOW WILL TRACK UP THROUGH NC INTO VA ON WED. SOME MOISTURE WILL CONTINUE TO WRAP AROUND THE SYSTEM INTO THE AREA BUT IT LOOKS LIKE BEST MID TO UPPER SUPPORT WILL LIE TO THE NORTH. CHANCE OF PCP WILL LINGER THROUGH WED BUT THURS AND FRI LOOK DRIER AS SUBSIDENCE INCREASES ON THE BACK END OF SYSTEM IN A DEEP W-NW FLOW. THIS DOWNSLOPE FLOW WILL PROMOTE DRIER WEATHER FOR THURS AND FRI BUT WILL ALSO HELP TO BOOST UP THE TEMPS BACK TO NORMAL. MID TO UPPER RIDGE WILL BUILD UP THROUGH THE SOUTHEAST WITH H5 HEIGHT RISES UP TO 580 DM...INCREASING A LITTLE FURTHER THROUGH SAT BEFORE DEEP MID TO UPPER TROUGH PUSHES EAST BY THE END OF THE WEEKEND. THIS DEEP MID TO UPPER TROUGH WILL PUSH A COLD FRONT EAST INTO THE CAROLINAS BY EARLY NEXT WEEK. A DEEP MOIST RETURN FLOW WILL SET UP AHEAD OF THE FRONT THROUGH THE END OF THE WEEKEND...INCREASING THE CHC OF SHWRS AND TSTMS. TEMPS IN THE MID 70S ON WED WILL SURPASS THE 80 MARK BY THURS AND WILL REMAIN WARM THROUGH THE WEEKEND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...TRICKY FORECAST CONTINUES AS UNSETTLED WEATHER BRINGS PERIODS OF MVFR AND IFR DUE TO VARYING LOW CIGS...AREAS OF FOG...AND RAIN SHOWERS...ESPECIALLY THROUGH THIS MORNING. OTHERWISE EXPECT VFR. VARYING CEILINGS AND VISIBILITIES IN SHOWERS AND BR THROUGH THIS MORNING. CONFIDENCE IS A BIT LOW GIVEN THE VARYING RAINFALL RATES. ALSO SOME CONCERN THAT FOG WILL ADVECT INTO PORTIONS OF THE AREA FROM THE SOUTH AS DEWPOINTS CONTINUE TO CLIMB INTO THE 60S. PERIODS OF HEAVIER RAINFALL WILL LIKELY CREATE BRIEF PERIODS OF IFR. AS DRIER AIR REACHES THE AREA LATER THIS MORNING AND THROUGH THE AFTERNOON...EXPECT VFR CONDITIONS TO DEVELOP AS CEILINGS AND LOWER VISIBILITIES IMPROVE AND THE RISK FOR SHOWERS DIMINISHES. SOUTHEAST WINDS AOB 12 KTS WILL GRADUALLY BECOME SOUTH IN THE AFTERNOON. TOWARDS THE END OF THE PERIOD...LIGHT WINDS AND VFR WILL PREVAIL. EXTENDED OUTLOOK...AN UPPER LOW WILL MOVE OVER THE AREA TUESDAY WITH SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EVENING. SMALL HAIL WILL BE POSSIBLE WITH UNUSUALLY LOW FREEZING LEVELS. AN ISOLATED SHOWER IS POSSIBLE WEDNESDAY AFTERNOON. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1115 PM SUNDAY...LATEST SFC PRESSURE PATTERN AND GRADIENT AHEAD OF THE APPROACHING BOUNDARY FROM THE SOUTH...CONTINUE TO SUPPORT EAST TO SOUTHEAST 15 TO 25 KT WINDS...WITH FEW GUSTS UP TO 30 KT. CURRENTLY THIS FRONT IS IN THE VICINITY OF CAPE ROMAIN SC...VIA LATEST SFC OBS. HRRR MODEL DATA SUPPORTS ITS SLOW PROGRESSION NORTHWARD OVERNIGHT INTO MONDAY. THE ILM SC WATERS WILL LIKELY SEE WINDS VEERING TO THE S OR SSW 10 TO 15 KT AFTER ITS PASSAGE DURING THE PRE-DAWN HRS OF MONDAY. IT MAY TAKE UP TO THE EARLY AFTERNOON HOURS OF MONDAY BEFORE PUSHING ACROSS AND NORTH OF THE ILM NC WATERS...THIS BASED ON LATEST NAM AND GFS MODEL OUTPUT. SIGNIFICANT SEAS WILL CONTINUE TO BE DOMINATED BY A PSEUDO NE-E DIRECTION SWELL AT 7 TO 8 SECOND DOMINANT PERIODS. OVERALL...SIG SEAS WILL RANGE BETWEEN 4 AND 8 FT...HIGHEST OUTER WATERS OFF CAPE FEAR AND WINYAH BAY...AND LOWEST SOUTH OF CAPE FEAR TO LITTLE RIVER INLET. AS WINDS SUBSIDE AFTER THE PASSAGE OF THE FRONTAL BOUNDARY...THE IMMEDIATE WIND DRIVEN WAVES WILL BEGIN TO SUBSIDE. HOWEVER...WAVEWATCH3 INDICATES A NE 10-11 SECOND PERIOD SWELL TO LITERALLY OCCUPY A LARGE CHUNK OF THE NORTH ATLANTIC BASIN. LATEST WAVEWATCH3 DOES INDICATE A SLOWER SUBSIDING TREND...WHEREAS THE LOCALLY PRODUCED SWAN IS A BIT TOO QUICK. PREFER THE SLOWER TREND. AS A RESULT...HAVE CONTINUED THE SCA MAINLY FOR SIG SEAS THRU MIDDAY MONDAY ACROSS THE ILM SC WATERS...AND LATE AFTERNOON MONDAY FOR THE ILM NC WATERS. OVERALL...AVERAGE PERIODS WILL RUN 5.5 SECONDS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...A NORTHEASTWARD MOVING OCCLUDED FRONT WILL SWEEP THROUGH THE AREA MONDAY MORNING. THIS IS VERY UNCHARACTERISTIC OF TYPICAL MAY WEATHER...BUT SEEMS TO BE PAR FOR THE COURSE FOR THIS SPRING. THE LAST OF THE STRONG EASTERLY WINDS WE HAVE EXPERIENCED ALL WEEKEND WILL ABATE AS THE FRONT CROSSES THE AREA. MONDAY AFTERNOON THROUGH TUESDAY NIGHT WILL SEE MUCH LIGHTER WIND SPEEDS WITHIN THE BAGGY PRESSURE PATTERN AROUND BROAD LOW PRESSURE OVER THE CAROLINAS. THIS LOW IS ACTUALLY A SURFACE REFLECTION OF A MUCH MORE POTENT LOW IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE WHICH SHOULD CREATE SHOWERY AND PERHAPS THUNDERY WEATHER AGAIN TUESDAY. THE SMALL CRAFT ADVISORY SHOULD BE ABLE TO DROP FOR THE NC WATERS EARLY MONDAY AFTERNOON AS LIGHTER WIND SPEEDS WILL NOT SUSTAIN SEAS AT OR ABOVE 6 FEET. OUTSIDE OF MONDAY MORNING...SEAS SHOULD BE DOMINATED BY 8 TO 10 SECOND EAST AND SOUTHEAST SWELL...WITH 2-4 FT HEIGHTS. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL TRACK UP FROM NORTH CAROLINA INTO THE MID ATLANTIC COAST WED INTO THURS. AS LOW LIFTS OFF FARTHER TO THE NE THROUGH THURSDAY...THE WINDS WILL SHIFT AROUND FROM SW TO W WED INTO THURS. WINDS WILL BACK TO THE SW LATE THURS AS WEAK HIGH PRESSURE BUILDS IN AND WILL SEE INCREASING RETURN FLOW OUT OF THE SOUTH TO SOUTHWEST AS HIGH SHIFTS OFF SHORE HEADING INTO THE WEEKEND. WINDS WILL GENERALLY REMAIN AROUND 10 KTS OR LESS THROUGH THE PERIOD. SEAS WILL GENERALLY STAY IN THE 2 TO 4 FT RANGE WITH A LOWERING TREND OF SEAS THROUGH MID WEEK IN THE OFF SHORE FLOW AND THEN A REVERSE TREND BY THE WEEKEND IN INCREASING SOUTHERLY PUSH. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT MONDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR AMZ250-252. && $$ NEAR TERM...DCH SHORT TERM...TRA LONG TERM...RGZ AVIATION...SGL/RJD
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
945 PM EDT TUE MAY 7 2013 .SYNOPSIS... AN UPPER LOW OVER THE CAROLINAS WILL MOVE NORTH INTO PENNSYLVANIA BY WEDNESDAY NIGHT AND THEN MOVE NORTHEAST ON THURSDAY TOWARD NEW ENGLAND. A COLD FRONT FROM THE NORTHERN PLAINS WILL SAG ACROSS THE AREA ON FRIDAY. A SECOND AND STRONGER COLD FRONT IS EXPECTED ON SATURDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... RADAR RETURNS CONTINUE TO DIMINISH AND HAVE LEFT A MENTION OF SPRINKLES FOR ANOTHER HOUR OR TWO. HRRR STILL SHOWING SOME NEW DEVELOPMENT IN THE EAST TOWARD MORNING SO WILL LEAVE SMALL CHANCES IN. NO CHANGES TO TEMPS. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/... AS THE UPPER LOW MOVES TOWARD PENNSYLVANIA WEDNESDAY AND MOVES ACROSS IT WEDNESDAY NIGHT SOME SHOWERS WILL SPREAD WEST INTO EASTERN OH AND NW PA. SOME QUESTION HOW FAR WEST IT WILL GET. WENT WITH THE PREVIOUS FORECAST AND KEPT IT DRY WEST OF CLEVELAND AND MANSFIELD. ON THE EDGE ABOUT THE THUNDER CHANCES. WITH THE LOW MOVING NORTH SOME THUNDER COULD GET INTO NW PA...SO MENTIONED A CHANCE. WITH THE LOW SO CLOSE TO EXTREME NE OH AND NW PA WENT SCATTERED AS THEY WILL HAVE THE BEST CHANCE. THE LIKELY MOS POPS SEEM TOO HIGH. A BREAK ON THURSDAY AS WE WAIT FOR THE NEXT SYSTEM. THE BEST CHANCE FOR MEASURABLE WITH THIS SYSTEM IS THURSDAY NIGHT INTO FRIDAY. && .LONG TERM /SATURDAY THROUGH TUESDAY/... FOR FRIDAY NIGHT INTO SATURDAY NIGHT SOME SHOWERS WILL BE AROUND. ON EDGE ABOUT THE THUNDER CHANCES...BUT THE AIRMASS WILL BE UNSTABLE SO WENT WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. USED A BLEND OF GUIDANCE. STARTING SUNDAY AT 12Z THE MODELS ARE FAIRLY CONSISTENT SHOWING A STRONG COLD FRONT DOWNSTREAM OF THE FORECAST AREA AND HIGH PRESSURE BUILDING OVER MUCH OF THE REGION. DRY AIR, CLEAR SKIES, AND LIGHT WIND WILL ALLOW TEMPERATURES TO DROP NEAR FREEZING ACROSS MOST OF THE FORECAST AREA SUNDAY NIGHT. TEMPERATURES WILL SLOWLY REBOUND THROUGH TUESDAY. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... FEW LINGERING SHOWERS NE OH WILL GRADUALLY DISSIPATE AFTER SUNSET. COULD SEE SOME MVFR CIG/BR TOWARD DAYBREAK. LOW PRESSURE SYSTEM OVER THE CAROLINAS WILL MOVE INTO WEST VIRGINIA TOMORROW MORNING EXPECT SCATTERED SHOWERS NE OH TOMORROW. IN ADDITION CHANCE OF TSRA NE OH TOMORROW AFTERNOON. .OUTLOOK...NON-VFR PROBABLE THURSDAY NIGHT AND FRIDAY IN SHRA/TSRA AND CHANCE OF SHOWERS SATURDAY. && .MARINE... OVER THE LAKE CONDITIONS CONTINUE TO BE DOMINATED BY THE HIGH OVER NEW ENGLAND OVERNIGHT. WINDS WILL REMAIN OUT OF THE NORTHEAST AROUND 5 TO 15 KT WHICH WILL KEEP WAVES UNDER 3 FEET. THE HIGH PRESSURE SYSTEM WILL BREAK DOWN AS AN AREA OF LOW PRESSURE OVER VIRGINIA MOVES NORTHEAST. AS A RESULT...THE PRESSURE GRADIENT WILL SLACKEN EVEN MORE AND THE WINDS WILL BE LIGHTER OVER THE LAKE. THE FLOW WILL REMAIN NORTHEAST/EAST INTO WEDNESDAY...BECOMING VARIABLE ON THURSDAY. A FRONT WILL APPROACH FRIDAY WHICH WILL INCREASE WINDS AND TURN THEM TO THE SOUTHWEST. ANOTHER FRONT WILL MOVE IN SATURDAY TURNING THE WINDS TO THE NORTHWEST. COLD AIR MOVING IN SUNDAY WILL CREATE CHOPPY BOATING CONDITIONS WITH WINDS APPROACHING SMALL CRAFT SPEEDS. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...KUBINA SHORT TERM...KIELTYKA LONG TERM...MAYERS AVIATION...DJB MARINE...JAMISON
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1130 PM CDT SUN MAY 5 2013 .UPDATE...FOR 06Z AVIATION FORECAST .AVIATION... UPPER LOW CENTERED OVER NORTHEAST ALABAMA AT 04Z WILL ROTATE UP INTO TENNESSEE AND THEN BACK DOWN INTO NORTHWEST GEORGIA OVER THE NEXT 24 HOURS. THIS WILL KEEP THE WEATHER UNSETTLED FOR AVIATION INTERESTS WITH LOW CEILINGS IN THE IFR RANGE AT TIMES ALONG WITH MORE SHOWER ACTIVITY ROTATING AROUND THE UPPER LOW. BY TUESDAY UPPER LOW FINALLY WORKS INTO THE CAROLINAS AS KICKER LOW DROPS INTO SOUTHERN CALIFORNIA. CAROLINA LOW FINALLY PHASES WITH BROAD UPPER TROUGH UP IN CANADA ON THURSDAY AND LIFTS OUT THROUGH THE NORTHEAST. BOYD && .PREV DISCUSSION... /ISSUED 833 PM CDT SUN MAY 5 2013/ UPDATE... SATELLITE IMAGERY SHOWS CENTER OF UPPER LEVEL LOW OVER NORTHERN ALABAMA...WHILE RADAR IMAGERY SHOWS BANDS OF RAIN AND A FEW THUNDERSTORMS CONTINUE TO THE NORTH OF THE CIRCULATION ACROSS THE SOUTHERN AND EASTERN CWA. HAVE SEEN SEVERAL LIGHTNING STRIKES AND REPORTS OF PEA SIZE HAIL WITH SOME OF THE STRONGER CONVECTIVE CORES...AND CANNOT RULE OUT SOME ADDITIONAL STRIKES OR HAIL FOR A FEW HOURS UNTIL INSTABILITY WANES OVERNIGHT. AFTERNOON HRRR MODEL RUNS INDICATES UPPER LOW WILL BE MAKING A CYCLOIDAL LOOP OVER THE NEXT 24 HOURS...MOVING EASTWARD INTO NORTHERN GEORGIA TONIGHT AND INTO EASTERN TENNESSEE BY SUNRISE...THEN BACK WESTWARD INTO THE MID STATE TOMORROW BEFORE RETURNING INTO NORTHERN GEORGIA MONDAY NIGHT. AS THE FIRST PART OF THIS LOOP OCCURS TONIGHT...RAIN ACROSS SOUTHEASTERN MID TN WILL PIVOT NORTHWESTWARD AROUND THE CIRCULATION WHICH SHOULD BRING RAIN INTO AT LEAST THE SOUTHEASTERN PARTS OF THE NASHVILLE METRO...WITH RAIN ALSO SPREADING ACROSS THE UPPER CUMBERLAND REGION AND PLATEAU THROUGH THE NIGHT. WESTERN ZONES LOOK TO STAY MOSTLY DRY WITH JUST A FEW SHOWERS. HAVE UPDATED GRIDS/ZONES MAINLY TO ADJUST TEMPS/POPS BASED ON LATEST OBS AND ADD MENTION OF THUNDER. SHAMBURGER PREV DISCUSSION... /ISSUED 643 PM CDT SUN MAY 5 2013/ UPDATE...FOR 00Z AVIATION FORECAST AVIATION... SEEMS LIKE I`VE BEEN MENTIONING THIS PESKY UPPER LOW FOR DAYS. WELL...IT`S NOW OVER NORTH ALABAMA WITH COLD CORE TEMPS DOWN TO -25 CELSIUS AT 500 MBARS. BANDS OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO ROTATE AROUND THE CENTER AND WILL WORK NORTHWEST TOWARD NASHVILLE THIS EVENING. LOOK FOR POOR FLYING CONDITIONS TO REDEVELOP THIS EVENING AND OVERNIGHT. UPPER LOW CURRENTLY HITTING WEST COAST WILL EVENTUALLY KICK PESKY UPPER LOW EASTWARD AND INTO THE CAROLINAS BUT NOT BEFORE TUESDAY. THIS BASICALLY MEANS AN UNSETTLED PERIOD OF WEATHER FOR THE MID STATE. BOYD PREV DISCUSSION... /ISSUED 445 PM CDT SUN MAY 5 2013/ UPDATE... HAVE UPDATED THE GRIDS/ZONES TO ADD A CHANCE OF THUNDERSTORMS TO SOUTHERN AREAS INTO THE EVENIGN AS AN ARC OF SCATTERED THUNDERSTORMS MOVES NORTHWEST INTO THE CWA. OTHER MORE WIDELY SCATTERED SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL DEVELOP FURTHER NORTHWARD AS WELL BENEATH COLD AIR ALOFT ASSOCIATED WITH UPPER LEVEL LOW OVER NORTHERN ALABAMA. A FEW OF THE STORMS WILL BE CAPABLE OF SMALL HAIL AND SOME GUSTY WINDS. REST OF FORECAST IS UNCHANGED. SHAMBURGER PREV DISCUSSION... /ISSUED 315 PM CDT SUN MAY 5 2013/ DISCUSSION... UPPER LOW MOVING SLOWLY EASTWARD ACROSS NRN AL. THIS FEATURE...ALONG WITH THE ASSOCIATED SURFACE TROUGH...IS EXPECTED TO SLOW DOWN AND POSSIBLY MEANDER TOWARD AND OVER THE MID STATE BY MONDAY AFTERNOON. IT IS THEN EXPECTED TO MOVE EASTWARD ACROSS THE CAROLINAS ON TUESDAY. AS A RESULT...OFF AND ON SHOWER ACTIVITY TO CONTINUE THROUGH MONDAY. UPCOMING QPF AMOUNTS DO NOT LOOK THREATENING WITH GENERALLY LESS THAN ONE HALF INCH EXPECTED THROUGH MONDAY. A BREAK FROM THE SHOWER ACTIVITY IS EXPECTED ON TUESDAY. FOR THE NEAR TERM POPS...GENERALLY 60-70% POPS SHOULD COVER IT TONIGHT AND MONDAY. FOR THE NEAR TERM TEMPS...WARMING TREND EXPECTED WITH HIGHS NEAR 70 ON TUESDAY AS MORE IN THE WAY OF SUNSHINE RETURNS. IN THE EXT FCST...AS THE PREVIOUSLY MENTIONED UPPER LOW DEPARTS...UPPER RIDGING AND WARMER WEATHER WILL OCCUR. ONCE THE RIDGE AXIS REACHES AND MOVES EAST OF MIDDLE TN BY THU NT...SHOWER AND TSTM CHANCES WILL BE ON THE INCREASE. NEXT FROPA LOOKS LIKE SAT NT. THUS...HIGHEST POPS OF AROUND 50% OR SO WILL BE FOR THE SAT AND SUN PERIODS. AS FOR THE EXT TEMPS...WE`LL SEE ABOVE NORMAL WARMTH THROUGH THE BULK OF THE PERIOD. HIGHS WILL REACH THE UPPER 70S-LOWER 80S FOR THU-SAT. COOLER SUNDAY. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 PM CDT SUN MAY 5 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 230 PM CDT SUN MAY 5 2013 MAIN FORECAST CONCERN IS ON ANY FOG POTENTIAL TONIGHT CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED UPPER HIGHS IN SOUTHERN BRITISH COLUMBIA AND OVER THE GREAT LAKES REGIONS...WHILE UPPER LOWS WERE PRESENT JUST WEST OF SAN FRANSISCO CA...OVER CENTRAL SOUTH DAKOTA AND OVER ALABAMA. THIS SETUP RESULTS IN LITTLE FLOW IN THE UPPER LEVELS ACROSS THE NORTHERN U.S.. THERE REMAINS SCATTERED-BROKEN HIGH CLOUDS OVER THE AREA...ON THE SOUTHWEST SIDE OF THE UPPER HIGH. OTHERWISE...A DRY AIRMASS HAS BEEN ADVECTING INTO THE FORECAST AREA FROM THE EAST...WITH THE 12Z GRB SOUNDING REFLECTIVE OF THE DRY AIR. THE COMBINATION OF THE DRY AIR...850MB TEMPS AROUND 8C...AND THE SUN HAS ALLOWED TEMPERATURES TO CLIMB INTO THE 65 TO 75 DEGREE RANGE WHERE SNOW DOES NOT EXIST. MEANWHILE...DODGE CENTER WHICH STILL HAS A DECENT AMOUNT OF SNOW ON THE GROUND...TEMPERATURES ARE STUCK IN THE MID 40S. REGARDING THE SEA LEVEL PRESSURE PATTERN...HIGH PRESSURE STRETCHED ACROSS NORTHERN MINNESOTA INTO NORTHERN ONTARIO...WHILE AN INVERTED TROUGH WAS PRESENT OVER WESTERN WISCONSIN...EXTENDING NORTH FROM LOW PRESSURE IN ALABAMA. LITTLE CHANGE IS PROGGED TO THE UPPER LEVEL PATTERN ACROSS THE UPPER MIDWEST INTO THE GREAT LAKES WITH PERHAPS JUST A SLIGHT BREAKDOWN OF THE UPPER RIDGE OVER THE GREAT LAKES. AS A RESULT...NOT EXPECTING MUCH CHANGE BETWEEN WHAT HAPPENED TODAY TO WHAT WILL HAPPEN TOMORROW. IF ANYTHING...WINDS SHOULD BE A BIT LIGHTER WITH THE HIGH PRESSURE AREA OVER NORTHERN ONTARIO PROGGED TO DRIFT SOUTH INTO NORTHERN WISCONSIN BY 00Z TUESDAY. PER 200-300MB RH PROGS...LOOKS LIKE THE SCATTERED TO BROKEN HIGH CLOUDS WILL PERSIST ACROSS THE AREA THROUGH MONDAY. THESE CLOUDS COMBINED WITH LIGHT NORTHERLY DRY ADVECTION SHOULD PRECLUDE ANY FOG DEVELOPMENT TONIGHT...DESPITE PERSISTENCE FROM SREF PROGS AND NMM CORE MODELS WHICH CONTINUE TO SHOW TOO HIGH OF DEWPOINTS. EVEN WORSE...THE 05.12Z NAM AND NCEP HIRES NMM MODELS BASICALLY HAD FOG AND TEMPS AROUND 34F AT KRST ALL DAY TODAY. NCEP HIRES ARW MODELS...WHICH ARE DOING BETTER WITH DEWPOINTS BUT STILL TOO HIGH...THIS TIME TONIGHT DO NOT SHOW FOG. REGARDING LOW...THE HIGH CLOUDS TONIGHT WILL KEEP TEMPERATURES UP SOMEWHAT...BUT THE DRY AIRMASS ALSO SUPPORTS READINGS FALLING...ESPECIALLY IN THE TYPICAL COLD SPOTS. TRENDED TOWARDS THE COLDER SIDE OF GUIDANCE. ON MONDAY...850MB TEMPS ARE STILL HOLDING AROUND 8C...SO EXPECTING HIGHS SIMILAR TO TODAY. ONLY DIFFERENCE WOULD BE OUT WEST WHERE LESSER SNOW SHOULD ALLOW FOR WARMER TEMPERATURES. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 230 PM CDT SUN MAY 5 2013 MONDAY NIGHT THROUGH WEDNESDAY...ONLY MAIN CONCERN FROM A PRECIPITATION PERSPECTIVE IS THE UPPER LOW SITUATED OVER CENTRAL SOUTH DAKOTA. HANDLING OF THIS UPPER LOW HAS BEEN VERY PROBLEMATIC RUN TO RUN AND BETWEEN MODEL TO MODEL. THERE HAS BEEN A GENERAL SLOW DOWN IN BRINGING THIS UPPER LOW TOWARDS THE AREA...WHICH MAKES SENSE AS IT IS CAUGHT IN A LACK OF FLOW BETWEEN THE NORTHERN AND SOUTHERN STREAMS. THE WAY MODELS EVENTUALLY BRING IT TOWARDS THE AREA IS FROM A NORTHERN STREAM TROUGH DROPPING INTO SOUTH CENTRAL CANADA...THUS PICKING UP THE UPPER LOW. THE 05.12Z GFS IS THE FASTEST SOLUTION... AND QUITE A BIT FASTER COMPARED TO ITS 05.06Z GFS...IMPACTING THE AREA DURING THE DAY WEDNESDAY. 05.12Z NAM/UKMET/CANADIAN AND 05.00Z/05.12Z ECMWF ARE SLOWER. BELIEVE SLOWER IS THE WAY TO GO...WHICH WOULD KEEP ANY PRECIPITATION FORCED BY THE UPPER LOW MOSTLY WEST OF THE AREA. THUS HAVE KEPT ANY PRECIPITATION CHANCES LOW AND CONFINED TO WESTERN SECTIONS. OTHERWISE...DRY CONDITIONS WILL PREVAIL UNDER THE INFLUENCE OF HIGH PRESSURE AND LITTLE IN THE WAY OF FLOW ALOFT. 850MB TEMPS HOLD IN THE 8-10C RANGE FOR BOTH TUESDAY AND WEDNESDAY...WHICH SHOULD YIELD HIGHS IN THE 70S BOTH DAYS WITH JUST SOME SCATTERED CLOUDS AROUND. A DRY AIRMASS ACCOMPANYING THE HIGH...LIGHT WINDS AND THE SCATTERED CLOUDS LIKELY TO ALLOW FOR DECENT COOLING AT NIGHT. STAYED TOWARDS THE COLD END OF GUIDANCE...PARTICULARLY FOR THE TYPICAL COLD SPOTS. WEDNESDAY NIGHT THROUGH SUNDAY...FOCUS AT THE BEGINNING OF THIS PERIOD REMAINS ON THE UPPER LOW AND A COLD FRONTAL BOUNDARY THAT LOOKS TO ACCOMPANY THIS UPPER LOW...AS WELL AS THE AFOREMENTIONED NORTHERN STREAM SHORTWAVE TROUGH. AS MENTIONED THE 05.12Z GFS WAS A BIT FAST WITH THE UPPER LOW...THUS PREFER THE SLOWER 05.00Z/05.12Z ECMWF. EITHER SOLUTION REQUIRES AT LEAST SOME CHANCES OF SHOWERS AND THUNDERSTORMS WITH THE COLD FRONTAL PASSAGE AND EVENTUALLY UPPER LOW. IT APPEARS THE COLD FRONT WILL SLOWLY DROP SOUTHEAST THROUGH THE AREA WEDNESDAY NIGHT THROUGH THURSDAY...WITH THE BEST CHANCES OF PRECIPITATION OVER SOUTHERN PORTIONS OF THE AREA CLOSER TO THE PROGGED UPPER LOW. CANADIAN HIGH PRESSURE BUILDS IN FOR FRIDAY...YIELDING DRIER AND SLIGHTLY COOLER CONDITIONS WITH 850MB TEMPS OF 6-8C. MODELS CONTINUE TO HINT AT BIG CHANGES FOR THE WEEKEND WITH THE 05.12Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES AND ECMWF ENSEMBLES ALL SHOWING A POTENT TROUGH DROPPING DOWN INTO THE WESTERN GREAT LAKES REGION. THIS TROUGH CURRENTLY IS IN THE ARCTIC NORTH OF SIBERIA... THUS EXPECTING A DECENT COLD SHOT. IN FACT...850MB TEMPS ARE PROGGED TO PLUMMET TO -4 TO -6C BY 12Z SUNDAY OVER THE FORECAST AREA. A COLD FRONT LOOKS TO RACE AHEAD OF THIS POTENT TROUGH...WHICH MEANS BETWEEN THE TWO A LIKELY DEFORMATION BAND OF LIGHT PRECIPITATION. THUS...CHANCES OF SHOWERS ARE IN THE FORECAST FOR SATURDAY. TEMPERATURES SATURDAY WILL BE TRICKY...ALL DEPENDING ON WHEN THE FRONT COMES THROUGH. IF IT IS SLOWER...850MB TEMPS OF 6-8C WOULD SUPPORT MOST LOCATIONS TOPPING OUT INTO THE 60S AND POSSIBLY EVEN LOW 70S LIKE THE 05.00Z ECMWF. ON THE OTHER HAND...A FASTER SOLUTION LIKE THE 05.12Z ECMWF/CANADIAN WOULD BE IN THE 50S...OR COLDER. FOR NOW WENT WITH THE COMPROMISE AND FOLLOWED A BLEND OF GUIDANCE FOR TEMPERATURES. DEFINITELY COLDER BUT DRIER FOR SUNDAY AS THE 850MB THERMAL TROUGH AND CANADIAN AIR MOVE IN. HIGHS LIKELY TO ONLY TOP OUT IN THE 50S ON SUNDAY...A GOOD 15 DEGREES OR SO BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1145 PM CDT SUN MAY 5 2013 A BRIEF PERIOD OF MVFR CONDITIONS IN BR IS POSSIBLE AT THE TAF SITES LATE TONIGHT INTO EARLY MONDAY MORNING. IF THE BR DEVELOPS...VISIBILITIES WOULD BE REDUCED INTO THE 4-5 SM RANGE. OTHERWISE...HIGH PRESSURE WILL BRING LIGHT WINDS AND VFR CONDITIONS TO THE TAF SITES. SCATTERED CIRRUS...WITH CLOUD BASES AT 20KFT...WILL DRIFT FROM SOUTHEAST TO NORTHWEST ACROSS THE TAF SITES THROUGH THE FORECAST PERIOD STREAMING OFF OF A BROAD CUTOFF LOW PRESSURE SYSTEM CENTERED OVER NORTHERN ALABAMA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1131 PM MDT TUE MAY 7 2013 .UPDATE... ISSUED AT 925 PM MDT TUE MAY 7 2013 UPDATED FOR CURRENT OBSERVATIONS AND RADAR TRENDS. HAVE KEPT CURRENT WINTER STORM WATCH FOR THE HIGH MT PEAKS...AOA 10K FEET AS QUICK PEAK AT 00Z NAM NOT AS BULLISH WITH QPF ACROSS THE REGION. STILL LOOKS LIKE BEST SNOW ACCUMS WILL BE ACROSS THE CENTRAL MTS AND POSSIBLY PIKES PEAK WITH ADVISORY AMOUNTS LIKELY...THOUGH WILL LET MID SHIFT GET A LOOK AT LATEST GLOBAL MODELS BEFORE ISSUING ANY HIGHLIGHTS. LATEST NAM PICKING UP ON THE HRRR AND RAP TRENDS OF SHOWERS DEVELOPING ACROSS THE SOUTHERN MTS AFTER MIDNIGHT AND SPREADING NORTH AND EAST THROUGH THE EARLY MORNING HOURS AS JETLET MOVES ACROSS THE SOUTHERN ROCKIES AND MID LEVEL DEFORMATION INCREASES ACROSS THE AREA. LATEST NAM QPF TREND ALSO BODES WELL FOR THE WALDO CANYON BURN SCAR...AND WILL WAIT AND SEE IF THE GLOBAL MODELS FOLLOW SUIT. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 243 PM MDT TUE MAY 7 2013 ACTIVE METEOROLOGICAL REGIME DURING THE SHORT TERM(ESPECIALLY WEDNESDAY) WITH ONE CONCERN BEING HEAVY RAIN POTENTIAL(SHOWERS AND THUNDERSTORMS)...ESPECIALLY OVER THE WALDO CANYON BURN SCAR BUT ALSO OVER MANY OTHER LOCATIONS OF THE FORECAST DISTRICT AS VIGOROUS CLOSED UPPER LOW SHIFTS FROM FAR NORTHWESTERN ARIZONA AT 00Z WEDNESDAY INTO SOUTHWESTERN COLORADO BY 00Z THURSDAY. I WILL BE ISSUING A FLOOD WATCH FOR THE FLASH FLOODING POTENTIAL(FOCUSED ON THE WALDO CANYON BURN SCAR AREA) FOR PUBLIC ZONES 81/84 AND 85 FROM 12Z WEDNESDAY THROUGH 00Z FRIDAY. ANOTHER CONCERN WILL BE THE STRONG TO SEVERE THUNDERSTORM POTENTIAL OVER PORTIONS OF THE SOUTHEASTERN COLORADO PLAINS FROM WEDNESDAY INTO WEDNESDAY NIGHT THANKS TO DEEPENING ATMOSPHERIC MOISTURE LEVELS...UPPER ENERGY MOVING ACROSS THE CWFA...0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS...LOCALIZED CAPES AROUND 1800 J/KG AND LOCALIZED LIS AROUND -6C. SPC 2ND DAY CONVECTIVE OUTLOOK HAS PORTIONS OF KIOWA...BENT...PROWERS AND BACA COUNTY IN THEIR SEVERE THUNDERSTORM OUTLOOK FOR WEDNESDAY. I WILL HAVE SEVERE THUNDERSTORM WORDING IN MY IMPENDING ZONES/GRIDS FOR THE ABOVE MENTIONED COUNTIES FOR WEDNESDAY AFTERNOON. AN ADDITIONAL METEOROLOGICAL ISSUE WILL BE THE POTENTIAL FOR HIGHER TERRAIN ACCUMULATING SNOW...ESPECIALLY FROM WEDNESDAY INTO THURSDAY. I WILL BE ISSUING A WINTER STORM WATCH FOR PUBLIC ZONES 58/60/73/75/80 AND 82 FROM 13Z WEDNESDAY TO 03Z FRIDAY TO ACCOUNT FOR THIS POTENTIAL. IN ADDITION..FOR TONIGHT I HAVE DEPICTED GENERALLY UNDER 4 INCHES OF SNOW OVER PORTIONS OF ZONES 58 AND 60 WILL LOWER SNOW AMOUNTS OVER OTHER HIGHER TERRAIN LOCATIONS. MINIMUM TEMPERATURES TONIGHT ARE EXPECTED TO RUN A CATEGORY OR SO ABOVE EARLY MAY CLIMATOLOGICAL AVERAGES MOST AREAS WHILE MAXIMUM TEMPERATURES ON WEDNESDAY SHOULD RUN A CATEGORY OR TWO BELOW EARLY MAY CLIMATOLOGICAL AVERAGES. FINALLY...LOW-GRADE GRADIENT WINDS ARE ANTICIPATED THROUGH 00Z THURSDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 243 PM MDT TUE MAY 7 2013 ...MORE HEAVY RAIN IN THE FORECAST... ...HEAVY WET SNOW FOR THE HIGHER ELEVATIONS... EXTENDED PERIOD CONTINUES TO LOOK FAIRLY WET...PARTICULARLY WED EVE THROUGH THU EVE...AND THEN ANOTHER ROUND LATE FRI INTO THE WEEKEND. MAIN CONCERN CONTINUES TO BE THE WALDO BURN SCAR DURING THIS TIME. WED EVE INTO THU...UPPER LOW OVER S CENTRAL CO WILL RETROGRADE WWD TO AZ BY THU EVE. HIGH PWATS CIRCULATING AROUND THE LOW WILL KEEP THE THREAT OF HEAVY SHOWER ACTIVITY GOING OVER MUCH OF OUR CWA. THE HIGHEST QPF STILL LOOKS TO BE OVER THE CONTDVD N OF KMYP...AND THE PIKES PEAK REGION. TOTAL QPF FOR THE WALDO AREA IS IN EXCESS OF ONE INCH...SO THE BURN SCAR WILL REMAIN UNDER THE GUN THROUGH THU... DURING THE TIME OF OUR FLASH FLOOD WATCH. MUCH OF THE ERN PLAINS WILL BE SOCKED IN WITH CLOUDS AND PRECIP AS UPSLOPE FLOW PERSISTS. THIS WILL LIMIT CONVECTIVE POTENTIAL OVER THE PLAINS AND COULD MEAN MORE OF A STRATIFORM EVENT...HOWEVER ISOLD TS WILL REMAIN A THREAT PARTICULARLY ALONG AND NR THE MTS. THERE WILL ALSO BE A LOW RISK OF SOME STRONG OR SVR CONVECTION OVER THE ERN PLAINS EARLY WED EVE. MOST OF THE HEAVIER CONVECTION SHOULD BE E OF OUR AREA AFTER 00Z WED...BUT ONE OR TWO STRONG STORMS COULD BE ONGOING OVER KIOWA COUNTY EARLY IN THE PERIOD. HAVE GONE ON THE LOW SIDE OF GUIDANCE FOR TEMPS ON THU...MAINLY UPPER 50S FOR THE PLAINS. H7 TEMPS WILL BE NR ZERO...AND WITH CLOUD COVER AND PRECIP DO NOT ANTICIPATE A LOT OF MIXING. SNOW LEVELS WILL REMAIN AROUND 9K FEET THROUGH THU FOR THE NRN RANGES...AND 10K FEET OR HIGHER FOR THE SW MTS. SO...EXPECT THE HEAVIER SNOW TOTALS TO BE ABOVE 11000 FEET...WITH SOME HEAVY WET SNOW FOR THE PASSES. HIGHEST ELEVATIONS SUCH AS PIKES PEAK AND THE HIGHER PEAKS IN THE SAWATCH AND SANGRES COULD SEE 1-2 FEET OF SNOW BY LATE THU. SNOW LEVELS COULD BRIEFLY DROP AS LOW AS 8 K FEET OR POSSIBLY LOWER IN HEAVIER SHOWERS. A BIT OF A RESPITE THU NIGHT INTO FRI MORNING BEFORE PRECIP CHANCES PICK UP AGAIN LATE FRI...AS A COLD FRONT RACES SWD THROUGH ERN CO. THIS WILL BRING ANOTHER PERIOD OF UPSLOPE TO THE PLAINS ON SAT. THE 12Z GFS ALSO SHOWS AN INFLUX OF DEEP MOISTURE INTO THE CENTRAL ROCKIES...ASSOCIATED WITH A SUBTROPICAL PLUME THAT WILL SLOWLY MOVE TO THE SE THROUGH EARLY NEXT WEEK. THIS MAY ACTUALLY END UP BEING AN EVEN GREATER THREAT FOR FLASH FLOODING...WITH THE POTENTIAL FOR STRONGER CONVECTION ALONG WITH THE HIGH PWATS. ENSEMBLE GRIDS REFLECT HIGH POPS THROUGH THIS PERIOD...AND SEE NO REASON TO CHANGE THEM AT THIS POINT. FOR THE WEEKEND...TEMPS WILL REMAIN BELOW AVERAGE...IN THE 60S FOR THE PLAINS AND 50S FOR THE MTS. FLOW SHOULD BECOME MORE W-SW FOR EARLY NEXT WEEK...WHICH WILL LEAD TO WARMER WX FOR THE AREA. ROSE && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1119 PM MDT TUE MAY 7 2013 FIRST WAVE OF -SHRA/-TSRA MOVING OFF TO THE NORTHEAST WITH NEXT WAVE ALREADY SPARKING SOME CONVECTION OVER NORTHERN NM. FOR KALS...A FEW -SHRA ALREADY INTO THE SRN SAN LUIS VALLEY AS OF 05Z...AND WILL LIKELY REACH THE TERMINAL 06Z-07Z. ACTIVITY LOOKS FAIRLY LIGHT AND SCT AT THIS POINT...SO WILL RUN WITH VFR CIGS AND ONLY A VCSH MENTION FOR NOW. EXPECT A FEW -SHRA TO LINGER OVER THE TERMINAL THROUGH THE DAY WED...SO KEPT VCSH GOING UNTIL EVENING...THOUGH AGAIN SHOWERS WILL BE FAIRLY LIGHT AND BRIEF. FOR KPUB AND KCOS...VFR CIGS EXPECTED THROUGH THE NIGHT...THOUGH -SHRA CHANCES WILL BE INCREASING 10-11Z AS PRECIP MOVES NORTH OUT OF NM. KEPT VFR CIGS GOING THROUGH THE DAY WED WITH VCSH THE ENTIRE PERIOD...WITH A WINDOW FOR POSSIBLE TSRA FROM 16-17Z UNTIL 22-23Z. OVER THE MOUNTAINS...EXPECT LOWERING CIGS OVERNIGHT WITH MOUNTAIN PEAKS OBSCURED FROM LATE TONIGHT THROUGH THE DAY WED DUE TO INCREASING -SHRA. && .PUB WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 6 AM MDT WEDNESDAY THROUGH THURSDAY AFTERNOON FOR COZ081-084-085. WINTER STORM WATCH FROM 7 AM MDT WEDNESDAY THROUGH THURSDAY EVENING FOR COZ058-060-073-075-080-082. && $$ UPDATE...MW SHORT TERM...77 LONG TERM...ROSE AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
601 AM EDT WED MAY 8 2013 .SYNOPSIS... A BROAD AREA OF LOW PRESSURE CENTERED OVER VIRGINIA EARLY TODAY WILL DRIFT TO THE NORTHEAST AND PASS SLOWLY OVER OUR REGION THROUGH THURSDAY. A WARM FRONT AND NEW AREA OF LOW PRESSURE MAY ORGANIZE NEAR THE MID ATLANTIC STATES FRIDAY NIGHT INTO SATURDAY. A COLD FRONT IS FORECAST TO FOLLOW EARLY ON SUNDAY WITH HIGH PRESSURE BUILDING TO OUR SOUTH ON MONDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE DEEP BUT ATLANTIC MOISTURE PLUME MOVING AROUND THE SLOWLY ADVANCING AND STACKED LOW AND SOME ELEVATED INSTABILITY WERE CAUSING A SWATH OF RAIN WITH SOME EMBEDDED THUNDER FROM WELL OFF THE SOUTHERN DELMARVA INTO NORTHEAST NEW JERSEY EARLY THIS MORNING. ACTIVITY QUICKLY BECAME MORE SCATTERED AS ONE MOVED SOUTHWEST. AS OF 09Z, THE MESOSCALE NAM AND THE HRRR HAD SHIFTED THE AXIS OF BEST RAINFALL FURTHER NORTH, BUT UNFORTUNATELY RADAR RETURNS SHOWED THE SWATH DEVELOPING A WESTWARD MOVEMENT. WE HAVE MENTIONED THE POSSIBILITY OF HEAVY RAIN THIS MORNING FROM EAST CENTRAL THROUGH NORTH CENTRAL NEW JERSEY AND INTO THE SOUTHERN POCONOS. ALL MODELS STILL SHIFT THE RAIN NORTH WITH TIME TODAY. OUR FORECAST STILL LIFTS THE PRECIPITATION NORTH AND OUT OF THE AREA THIS MORNING AND THEN RE-FOCUSES ON THE LOW. SOME ENERGY IS FORECAST TO REVOLVE AROUND THE LOW, AND IT ESPECIALLY SEEMS TO TARGET OUR WESTERN ZONES. WE CARRY A SLIGHT CHANCE OF THUNDER FIRST WITH THE SWATH OFF THE OCEAN. WE THEN EXTEND THE SLIGHT CHANCE AROUND THE FORECAST AREA AS THE LOW APPROACHES AND TEMPERATURES COOL ALOFT. MID LEVEL CLOUDS HAD BROKEN FAR SOUTH, AND THIS HAD ALLOWED SOME FOG TO FORM THERE. THAT IS COVERED IN THE FORECAST AND WITH A SPECIAL WEATHER STATEMENT THAT RUNS UNTIL 1330Z. TEMPERATURES ARE ON THE COOLER SIDE OF GUIDANCE, ALTHOUGH WE DO START FROM A FAIRLY WARM PLACE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... THE MODELS SHOW DECENT AGREEMENT REGARDING MORE ENERGY ROTATING AROUND THE LOW AND LIFTING FROM THE SOUTH INTO OUR FORECAST AREA TONIGHT, AND WE CARRY HIGH CHANCE POPS IN RESPONSE. AGAIN, WE ARE NOT MENTIONING ANY HEAVY RAIN. WE DO CARRY THUNDER THROUGH THE EVENING. TEMPERATURES ARE A GUIDANCE/CONTINUITY BLEND. && .LONG TERM /THURSDAY THROUGH TUESDAY/... UNSETTLED CONDITIONS WILL REMAIN ACROSS THE AREA FROM THURSDAY INTO THE WEEKEND. FIRST...THE WEAKENING UPPER LOW WILL CONTINUE TO TRANSLATE NORTHEAST ACROSS THE REGION. WHILE THE SYSTEM IS NOT VERY STRONG...IT WILL HAVE ENOUGH ENERGY/INSTABILITY TO CREATE SOME SCT SHOWERS INTO THE FIRST PART OF THE EXTENDED. A BRIEF BREAK BEHIND THE LOW MAY CREATE LESSER CHC FOR PCPN FRIDAY...THEN ANOTHER SYSTEM APPROACHED FROM THE OHIO VALLEY FRI NIGHT AND LINGERS ACROSS THE AREA INTO SUNDAY. THE APPROACHING SYSTEM LATER FRI MAY ARRIVE EARLY ENOUGH TO PRODUCE SOME SVR TSTMS ACROSS THE NW ZONES. THE SPC HAS PLACED A SLGT RISK FOR SVR TSTMS THAT DAY. A COLD FRONT WILL BRING DRIER AIR AND COOLER TEMPERATURES LATER SUNDAY. THESE COOLER READINGS WILL LAST INTO EARLY NEXT WEEK. EXCEPT FOR FRIDAY...TEMPERATURES WILL MOSTLY BE NORMAL OR BELOW NORMAL ACROSS THE REGION. ON FRIDAY...DAYTIME HEATING SHOULD BOOST READINGS WELL INTO THE 70S AND LOW 80S ACROSS THE AREA. IT WILL REMAIN COOLER ALONG THE SHORE ON FRIDAY. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. WIDELY SCATTERED ACTIVITY THREATENING THE TAF SITES EARLY THIS MORNING WAS MOSTLY LIGHT. THE STEADY EAST WIND AND A SOLID DECK OF MID LEVEL CLOUDINESS WAS KEEPING ANYTHING OTHER THAN SOME MVFR FOG FROM FORMING, BUT STRATUS WAS DEVELOPING AROUND THE DELAWARE VALLEY AND NORTHWESTERN SITES ON THAT EAST WIND. THAT SAID, THERE WAS AN AREA OF DRIER AIR MOVING UP FROM SOUTHEASTERN VA, MUCH OF THE DELMARVA AND FAR SOUTHERN NJ THAT WAS CAUSING THE MID LEVEL CLOUDS AND STRATUS TO ERODE. THAT WAS QUICKLY FOLLOWED BY THE DEVELOPMENT OF SOME IFR FOG OVER SOUTHERN DELAWARE AND THE ADJACENT MARYLAND EASTERN SHORE. ON THE ONE HAND, IT`S BY NO MEANS CERTAIN THAT THE FOG CAN ADVANCE INTO THE TAF SITES BECAUSE WE`RE NOT SURE THAT THE DRY AIR PUSHES FAR ENOUGH NORTH. ON THE OTHER HAND, WE`RE NOT CERTAIN THAT THE STRATUS STAYS ERODED WITH A FLOW OFF THE OCEAN. THE PRESENT TAFS ARE OPTIMISTIC IN BREAKING STRATUS EARLIER THAN WE HAD BEEN FORECASTING AND IN NOT FORECASTING MUCH IN THE WAY OF FOG. ALL SITES BREAK OUT TO VFR BY 16Z IN THE PRESENT TAFS, WITH THE SOUTHEASTERN AND DELAWARE VALLEY SITES BREAKING OUT DURING THE DAYLIGHT MORNING HOURS. WE WILL MONITOR. WE HAVE CONTINUED THE OPTIMISTIC FORECAST INTO THE AFTERNOON BY ONLY FORECASTING A PROB30 FOR TSTM ACTIVITY AT MOST SITES (NOT THE SOUTHEASTERN ONES) AND THEN GOING VFR THROUGH 09/06Z (12Z AT PHL). WE MAY ULTIMATELY INSERT AT LEAST SOME STRATUS INTO THE FORECAST FOR THE PERIOD AFTER 06Z IN SUBSEQUENT ISSUANCES. WINDS ARE NOT EXPECTED TO BE A MAIN CONCERN TODAY, BUT THEY SHOULD VEER FROM EAST OR NORTHEAST TO SOUTHEAST DURING THE TAF PERIOD AT 10 KT OR LESS. OUTLOOK... THU INTO FRI NIGHT...MOSTLY VFR. SCATTERED SHOWERS/TSTMS FRI AFTERNOON MAY BRING LOWER CIGS/VSBYS. SAT THRU SUN...LOWER CONDITIONS EXPECTED WITH CIGS/SHOWERS SAT AND SAT NIGHT. IMPROVING CONDITIONS LATER SUNDAY. && .MARINE... WITH BROAD LOW PRESSURE APPROACHING OUR REGION AND A CONTINUED ONSHORE FLOW, SEAS ARE EXPECTED TO BE ELEVATED THROUGH TONIGHT ON OUR ATLANTIC COASTAL WATERS. A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CONTINUES FOR ALL OF OUR ATLANTIC COASTAL WATERS THROUGH TONIGHT. SEAS AND WINDS ARE EXPECTED TO REMAIN BELOW SCA LEVELS FOR DELAWARE BAY. VISIBILITIES WILL BE LOWERED AT TIMES IN SCATTERED SHOWERS AND ISOLATED THUNDER MAINLY THIS AFTERNOON, ALTHOUGH NORTHERN ATLANTIC WATERS WILL SEE SOME HEAVIER RAIN AND PERHAPS SOME THUNDER EARLY THIS MORNING. ANOTHER SHOT OF SHOWER AND THUNDERSTORM ACTIVITY IS POSSIBLE TONIGHT. OUTLOOK...SCA CONDITIONS FOR HAZ SEAS WILL PROBABLY COME DOWN THU MORNING AS THE LONGER PERIOD SWELLS DIMINISH. ANOTHER PERIOD OF SCA CONDITIONS WILL DEVELOP ACROSS THE OCEAN WATERS FRI NIGHT AND LAST INTO THE WEEKEND. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT THURSDAY FOR ANZ450>455. && $$ SYNOPSIS...GIGI/O`HARA NEAR TERM...DELISI SHORT TERM...DELISI LONG TERM...O`HARA AVIATION...DELISI MARINE...DELISI
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
215 AM EDT WED MAY 8 2013 .PREV DISCUSSION... /ISSUED 730 PM EDT TUE MAY 7 2013/ SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... MAIN FORECAST CONCERN IN THE SHORT TERM IS ASSOCIATED WITH SOME LINGERING MOISTURE AND WEAK VORT MAXS ROTATING AROUND THE PERSISTENT UPPER LOW CURRENTLY SITUATED ACROSS THE CAROLINAS. SO FAR THIS AFTERNOON...IT HAS ALLOWED FOR ENHANCED CU FIELD DEVELOPMENT AND SOME ISOLATED SHOWERS AND STORMS JUST EAST OF THE CWA. THERE IS ENOUGH ELEVATED INSTABILITY TO MAINTAIN THE LOW END CHANCE FOR ISOLATED THUNDERSTORMS MAINLY ACROSS PORTIONS OF THE EAST THROUGH THE REST OF TODAY. FOR TONIGHT...POPS SHOULD BE ON THE DECREASE ACROSS THE NORTHEAST. WITH GUIDANCE LIKELY UNDERDOING THE SFC MOISTURE PRESENT FROM RECENT RAINFALL...THERE IS A GOOD CHANCE FOR FOG DEVELOPMENT UNDER THE CALM TO LIGHT WINDS IN THE EARLY MORNING HOURS. GUIDANCE IS IN GENERAL AGREEMENT WITH SOME LOW LEVEL MOISTURE ADVECTING INTO THE FAR NORTHERN PORTION NEAR 12Z. SHORT RANGE ENSEMBLE RESTRICTED VSBY PROBS AND RUC CONDENSATION PRESSURE DEFICIT SUPPORT THE GREATEST CHANCE FOR MORE WIDESPREAD FOG DEVELOPMENT TO BE IN THE FAR NORTH OR NORTHWEST. CONFIDENCE IS LOW AT THIS POINT ON DENSE FOG DEVELOPMENT AND WILL MENTION PATCHY FOG AREA-WIDE FOR NOW. AS UPPER LOW FINALLY BEGINS ITS EXIT NEWD AND WEAK RIDGING TEMPORARILY BUILDS IN...HAVE TRENDED POPS TO MAINLY BE FOCUSED IN THE FAR NORTH AND NORTHEAST THROUGH WEDNESDAY NIGHT. FORECAST MUCAPE VALUES SUGGEST ISOLATED THUNDERSTORM DEVELOPMENT IS POSSIBLE AGAIN DURING THE AFTERNOON WEDNESDAY. FOR TEMPS...A GENERAL BLEND IN THE SHORT TERM GUIDANCE LOOKED REASONABLE AS THE FORECAST AREA SHOULD CONTINUE A GRADUAL WARM-UP AHEAD OF THE NEXT SYSTEM DURING THE WEEKEND. BAKER LONG TERM /THURSDAY THROUGH TUESDAY/... HAVE MADE NO CHANGES TO THE EXTENDED. MODELS AGREE O BRIEF BREAK FOR MUCH OF THE CWA WEDNESDAY NIGHT INTO THURSDAY WITH RAIN CHANCES INCREASING AGAIN ON FRIDAY. SERIES OF SHORT WAVES SHOULD KEEP CHANCE OF RAIN ACROSS THE FORECAST AREA THROUGH SUNDAY...WITH DRYING SUNDAY INTO MONDAY WITH PASSAGE OF A SURFACE FRONT. HAVE INCLUDED THE PREVIOUS LONG TERM DISCUSSION BELOW. 41 LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... /ISSUED AT 411 AM EDT TUE MAY 7 2013/ BY WEDNESDAY NIGHT...PESKY UPPER LOW MOVES UP OVER THE MID ATLANTIC STATES...WITH RESIDUAL MOISTURE ACROSS NORTH AND NORTHEAST GEORGIA. BRIEF REPRIEVE EXPECTED ACROSS THE REMAINING CWA THURSDAY INTO FRIDAY AHEAD OF THE NEXT BATCH OF RAIN. EXTENDED MODELS STILL SHOWING COMBINATION OF ENHANCED MOISTURE FROM DEEP SOUTHERLY FLOW AND SERIES OF UPPER LEVEL DISTURBANCES WILL BRING BACK TO THE STATE BY FRIDAY AHEAD OF FRONT PUSHING THROUGH THE STATE OVER THE WEEKEND. HAVE OPTED TO INCREASE POPS SLIGHTLY FRIDAY...WITH GOOD CHANCE NORTH WITH SLIGHT CHANCE THROUGH THE METRO AREA. HAVE CONTINUED WITH INCREASING TREND INTO SATURDAY WITH LIKELY POPS NORTH AND GOOD CHANCE ACROSS MUCH OF THE REST OF THE AREA. THUNDERSTORMS LOOK TO BE LIKELY WITH THIS EVENT WITH GOOD MODEL AGREEMENT WITH THE INSTABILITY...ESPECIALLY SATURDAY. MODELS CONTINUE TO DIFFER ON THE AMOUNT OF QPF EXPECTED FRIDAY THROUGH SUNDAY...WITH THE WETTER ECMWF SHOWING LARGE PORTION OF WESTERN GEORGIA COULD SEE 0.75 TO 1.25 INCHES WITH ISOLATED HIGHER AMOUNTS...AND THE GFS SHOWING NORTH GEORGIA COULD SEE WIDESPREAD 0.5 INCHES...WITH PORTIONS OF NORTHWEST GEORGIA SEEING UP TO AN INCH. HAVE GENERALLY GONE WITH THE GFS SOLUTION FOR QPF...WHICH MAY BE WISHFUL THINKING AFTER THIS VERY WET WEEKEND ACROSS THE STATE. NEAR NORMAL TEMPERATURES ARE EXPECTED WEDNESDAY AND THURSDAY MORNING...WITH WARM UP BY WEDNESDAY AFTERNOON TO ABOVE NORMAL TEMPERATURES WHICH WILL REMAIN IN PLACE INTO THE WEEKEND. PRECIP ACTIVITY SATURDAY AND SUNDAY WILL KEEP TEMPERATURES CLOSER TO SEASONAL. 31 && .AVIATION... 06Z UPDATE... VFR CONDITIONS EXPECTED THROUGH THE PERIOD. PATCHY FOG IS EXPECTED...BUT NOT ANTICIPATED TO IMPACT ANY TAF SITES AT THIS TIME. WEST WINDS WILL INCREASE TO 8-11KT THROUGH THE DAY...AND DIMINISH TO 5-8KT BY 00Z. //ATL CONFIDENCE...06Z UPDATE... HIGH CONFIDENCE ON ALL ELEMENTS...EXCEPT MEDIUM CONFIDENCE ON POTENTIAL FOG DEVELOPMENT THROUGH 12Z. 31 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 78 56 84 58 / 20 10 10 10 ATLANTA 77 59 81 61 / 10 5 10 10 BLAIRSVILLE 71 51 77 55 / 30 20 20 20 CARTERSVILLE 76 54 81 58 / 10 10 10 20 COLUMBUS 80 60 85 60 / 10 5 5 10 GAINESVILLE 74 56 80 59 / 20 20 10 20 MACON 79 56 84 58 / 10 10 5 10 ROME 77 53 83 57 / 10 10 10 20 PEACHTREE CITY 78 53 82 57 / 10 5 5 10 VIDALIA 80 61 85 62 / 10 10 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...31 LONG TERM....39 AVIATION...31
AREA FORECAST DISCUSSION
NWS TOPEKA KS
359 AM CDT WED MAY 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM CDT WED MAY 8 2013 08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB. FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS. LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND POSSIBLY SOME DAMAGING WIND GUSTS. WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3 AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH. SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON THE WARM SIDE OF THE TROUGH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 356 AM CDT WED MAY 8 2013 ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY. A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN THE LOW TO MIDDLE 80S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 356 AM CDT WED MAY 8 2013 CONVECTIVE COMPLEX EXPECTED TO CONTINUE EAST INTO THE TERMINALS THROUGH 08-10Z...WITH ADDITIONAL DEVELOPMENT ONGOING IN SOUTHWEST KANSAS AND LIKELY TO JOIN THE COMPLEX INTO THE POST-SUNRISE HOURS PER RECENT HRRR AND NAM RUNS. LIMITATIONS SHOULD REMAIN WITH VISIBILITIES DOWN TO MVFR LEVELS WITH THE STRONGER CELLS. BACKED OFF WITH ADDITIONAL DEVELOPMENT GIVEN SLOWER BOUNDARY AND SOME TIME FOR ATMOSPHERE TO RECOVER. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...WOLTERS LONG TERM...63 AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1151 PM CDT TUE MAY 7 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 335 PM CDT TUE MAY 7 2013 A BLOCKING PATTERN WAS IN PLACE OVER THE REGION TODAY AS UPPER LEVEL LOWS WERE SITUATED OVER BOTH THE SOUTHEASTERN AND SOUTHWESTERN U.S. WITH A WEAK RIDGE OVER THE SOUTHERN PLAINS. A SHORTWAVE THAT WAS EMBEDDED IN THE RIDGE LIFTED NORTHWARD INTO KANSAS TODAY. ENOUGH LIFT WAS PRESENT WITH THIS WAVE TO AID IN THE DEVELOPMENT OF SHOWERS ACROSS WESTERN AND CENTRAL KANSAS THIS MORNING INTO THIS AFTERNOON. HOWEVER...LATEST RADAR TRENDS SHOW THIS LINE OF SHOWERS OVER CENTRAL KANSAS BEGINNING TO WEAKEN AND DISSIPATE AS THEY TRACK FURTHER EAST AS A RESULT OF THE WAVE WEAKENING AS IT BECOMES WRAPPED UP IN THE BROAD UPPER LOW STATIONED ACROSS THE NORTHERN PLAINS. HAVE TRENDED DOWN WITH POPS ACROSS MUCH NORTHEASTERN AND EAST CENTRAL KANSAS THROUGH THE EARLY EVENING HOURS WITH CHANCE POPS IN PLACE OVER NORTH CENTRAL KANSAS AS THE WAVE PASSES OVER THE AREA. THIS WAVE LOOKS TO AMPLIFY A BIT AS IT TRACKS EASTWARD ACROSS NORTHERN KANSAS OVERNIGHT INTO WEDNESDAY MORNING...SO HAVE INCREASING POPS OVER THIS AREA. WITH A SOUTHERLY FLOW IN PLACE OVER THE REGION THROUGH THE OVERNIGHT HOURS...THE COMBINATION OF WAA AND INCREASING CLOUD COVER WILL ALLOW FOR SOME ISOLATION OVERNIGHT AND LOW TEMPERATURES TO ONLY DROP INTO THE MIDDLE 50S. SCATTERED SHOWERS WITH SOME ELEVATED THUNDERSTORMS MAY SPREAD EASTWARD ACROSS THE FORECAST AREA THROUGH THE MORNING HOURS AS THE WAVE PROGRESSES EAST OF THE CWA BY WEDNESDAY AFTERNOON. THERE IS SOME UNCERTAINTY REGARDING HOW MUCH SUN WILL BE ABLE TO BREAK THROUGH THE CLOUDS BEHIND THIS EXITING WAVE...WHICH WILL EFFECT HOW MUCH HEATING WILL BE ABLE TO OCCUR TO CAUSE SOME DESTABILIZATION OVER THE REGION THROUGH THE AFTERNOON HOURS. AT THIS TIME...AFTERNOON HIGHS FOR WEDNESDAY SHOULD REACH INTO THE LOWER TO MIDDLE 70S. WHILE THE BETTER POTENTIAL FOR THUNDERSTORM DEVELOPMENT LOOKS TO BE IN THE VICINITY OF THE DRYLINE THAT SETS UP OVER WESTERN OKLAHOMA AND SOUTHWESTERN KANSAS...ADDITIONAL DEVELOPMENT IS POSSIBLE ACROSS THE FORECAST AREA BY MID TO LATE AFTERNOON IF ENOUGH DESTABILIZATION OCCURS. MODELS SHOW A BOUNDARY EXTENDING FROM THE SURFACE LOW OVER THE TEXAS/OKLAHOMA PANHANDLES AND STRETCHING NORTHEASTWARD INTO NORTH CENTRAL KANSAS BEFORE GRADUALLY SHIFTING SOUTHWARD ACROSS THE FORECAST AREA THROUGH THE EVENING HOURS. THERE IS STILL SOME UNCERTAINTY REGARDING THE EXACT LOCATION OF THIS BOUNDARY BY LATE AFTERNOON...WHICH WILL EFFECT WHERE THE GREATEST POTENTIAL FOR ANY THUNDERSTORM DEVELOPMENT WILL BE. HENNECKE .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 335 PM CDT TUE MAY 7 2013 WEDNESDAY NIGHT...A BROAD UPPER LEVEL TROUGH OVER THE FOUR CORNERS AREA 00Z THU WILL FILL AS IT LIFTS EAST-NORTHEAST INTO THE CENTRAL AND SOUTHERN PLAINS. A SURFACE COLD FRONT WILL PUSH SOUTHWARD ACROSS THE CWA DURING THE NIGHT. ONGOING THUNDERSTORMS ALONG AND SOUTH OF THE SURFACE FRONT WILL CONTINUE THROUGH THE NIGHT. SOME OF THE THUNDERSTORMS DURING THE EVENING HOURS MAY BE SEVERE AS SBCAPE WILL BE AROUND 1500 J/KG AND SFC TO 6KM BULK SHEAR WILL BE ABOUT 30 KTS THROUGH 3Z. THE PRIMARY HAZARDS WITH ANY ORGANIZED SEVERE SURFACE BASED STORM WILL BE LARGE HAIL AND ISOLATED DAMAGING WIND GUSTS. NORTH OF THE BOUNDARY ELEVATED THUNDERSTORMS MAY PRODUCE PENNY TO QUARTER SIZE HAIL. IF THE SURFACE FRONT REMAINS STATIONARY ACROSS THE CENTRAL PORTIONS OF THE CWA EARLY WEDNESDAY EVENING...THEN AN ORGANIZED SUPERCELL MAY RIDE ALONG THE BOUNDARY AND INGEST BAROCLINICALLY GENERATED STREAM-WISE HORIZONTAL VORTICITY AND MAY PRODUCE ISOLATED TORNADOES. HOWEVER...IF THE FRONT SLOWLY MOVES SOUTHEAST ACROSS THE CWA...THEN MOST LIKELY THE SURFACE FRONT WILL UNDERCUT ANY SURFACE BASED INFLOW AND DIMINISH THE THREAT FOR ISOLATED TORNADOES. ISENTROPIC LIFT NORTH OF THE BOUNDARY WILL KEEP RAIN AND ELEVATED THUNDERSTORMS CHANCES THROUGH THE NIGH. BOTH THE NAM AND ECMWF SHOW THE INSTABILITY DECREASING THROUGH THE NIGHT TO LESS THAN 500 J/KG AFTER MIDNIGHT. THUS ANY STRONG ELEVATED STORMS AFTER MIDNIGHT WILL ONLY PRODUCE SMALL HAIL. THURSDAY AND THURSDAY NIGHT...SKIES WILL BE MOSTLY CLOUDY WITH PERIODS OF SHOWERS AND ISOLATED ELEVATED THUNDERSTORMS. MUCAPE NORTH OF THE FRONT WILL ONLY RANGE FROM 100-400 J/KG...THUS THE STRONGER ELEVATED THUNDERSTORMS WILL ONLY PRODUCE SMALL HAIL. FRIDAY...THE SHOWERS SHOULD END FROM NORTH TO SOUTH ACROSS THE CWA AS THE H5 TROUGH ACROSS NORTHERN MO SHEARS APART. FRIDAY NIGHT...SHOULD REMAIN DRY AS AN H5 TROUGH DIGS SOUTHEAST FROM CENTRAL CANADA INTO THE UPPER MIDWEST. SATURDAY AND SATURDAY NIGHT...THE H5 TROUGH WILL DIG AND AMPLIFY ACROSS THE SOUTHERN GREAT LAKES STATES. THIS WILL CAUSE A COLD FRONT TO RAPIDLY PUSH SOUTHEAST ACROSS THE CWA DURING THE MID AND LATE MORNING HOURS OF SATURDAY. THERE MAY BE ENOUGH LIFT AHEAD OF THE FRONT AND ON THE WESTERN EDGE OF THE H5 TROUGH TO CAUSE A FEW ISOLATED SHOWERS OR THUNDERSTORMS...BUT THESE SHOWERS SHOULD PUSH SOUTHEAST OF THE CWA DURING THE EARLY AFTERNOON HOURS. NORTH WINDS WILL INCREASE TO 15 TO 20 MPH WITH SOME GUSTS TO 30 MPH. HIGH TEMPERATURES WILL PROBABLY OCCUR DURING THE LATE MORNING AND EARLY AFTERNOON HOURS IN THE LOWER TO MID 60S AND THEN HOLD STEADY OR EVEN FALL SLIGHTLY DURING THE AFTERNOON HOURS. THE CENTER OF THE SURFACE RIDGE WILL BUILD SOUTHWARD ACROSS EASTERN KS SATURDAY NIGHT. LIGHT WINDS AND CLEAR SKIES WILL ALLOW TEMPERATURES TO DROP INTO THE UPPER 30S TO LOWER 40S. DEWPOINT TEMPERATURES SHOULD BE IN THE UPPER 20S...SO I DON`T THINK FROST WILL FORM. SUNDAY AND SUNDAY NIGHT...WILL BE ANOTHER COOL DAY WITH HIGHS IN THE MID 60S. LIGHT WINDS WILL BECOME SOUTHERLY THROUGH THE LATE AFTERNOON AND INTO THE NIGHT. SOUTHERLY SURFACE WINDS WILL KEEP OVERNIGHT LOWS IN THE MID 40S. MONDAY THROUGH TUESDAY...EXPECT A WARMING TREND AS AN H5 RIDGE MOVES EAST ACROSS THE PLAINS. SOUTHERLY WINDS WILL HELP HIGHS TO WARM INTO THE MID 70S ON MONDAY AND INTO THE LOWER TO MID 80S ON TUESDAY. GARGAN && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1150 PM CDT TUE MAY 7 2013 CONVECTIVE COMPLEX EXPECTED TO CONTINUE EAST INTO THE TERMINALS THROUGH 08-10Z...WITH ADDITIONAL DEVELOPMENT ONGOING IN SOUTHWEST KANSAS AND LIKELY TO JOIN THE COMPLEX INTO THE POST-SUNRISE HOURS PER RECENT HRRR AND NAM RUNS. LIMITATIONS SHOULD REMAIN WITH VISIBILITIES DOWN TO MVFR LEVELS WITH THE STRONGER CELLS. BACKED OFF WITH ADDITIONAL DEVELOPMENT GIVEN SLOWER BOUNDARY AND SOME TIME FOR ATMOSPHERE TO RECOVER. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HENNECKE LONG TERM...GARGAN AVIATION...65
AREA FORECAST DISCUSSION
NWS JACKSON KY
133 AM EDT WED MAY 8 2013 .UPDATE... ISSUED AT 133 AM EDT WED MAY 8 2013 MADE A QUICK UPDATE TO THE FORECAST. NO MAJOR CHANGES WERE MADE TO THE FORECAST GRIDS THEMSELVES...BUT WITH LOCALLY DENSE FOG SHOWING UP IN OBS ACROSS EASTERN KENTUCKY...DECIDED TO GO AHEAD AND MENTION THE POSSIBILITY OF LOCALLY DENSE FOG IN THE ZONE FORECAST TEXT PRODUCT. THE GRIDS ALREADY HAVE PATCHY DENSE FOG IN THE WEATHER TYPE ELEMENT THROUGH 12Z THIS MORNING...SO IT WAS JUST A MATTER OF MENTIONING IT IN THE FORECAST TEXT PRODUCT AND HAZARDOUS WEATHER OUTLOOK. WILL ISSUE TO UPDATED ZONES SHORTLY. UPDATE ISSUED AT 830 PM EDT TUE MAY 7 2013 HOURLY POPS...TEMPS AND DEWPOINTS WERE UPDATED BASED ON RECENT TRENDS RADAR...SATELLITE AND MODEL TRENDS. SOME OF THE MODELS... PARTICULARLY RECENT HRRR...ARE HANDLING THE BAND OF SHOWERS MOVING ACROSS THE SOUTHWEST HALF OF THE CWA RATHER WELL. THE NAM AND THE GFS BRING ANOTHER WEAK SHORTWAVE AROUND THE MAIN CIRCULATION AND SPREAD SOME SHOWERS INTO THE SOUTHEASTERN COUNTIES LATER TONIGHT... TOWARD DAWN. THE NAM AND HRRR MINIMIZE THIS MORE THAN THE GFS AND CONFINE IT MORE TO FAR SOUTHEAST KY. NO THUNDER HAS BEEN OBSERVED OVER THE PAST HOUR SO WE HAVE OPTED TO REMOVE THUNDER FROM THE FORECAST OVERNIGHT. FOG HAS ALREADY DEVELOPED IN THE JKL VICINITY AND VALLEYS NEAR WHERE PRECIPITATION WAS HEAVIER IN THE EVENING. SO FOG SHOULD CONTINUE EARLIER THAN CLIMATOLOGY AND AND IF SKIES REMAIN CLEAR ENOUGH IT MAY BECOME DENSE AROUND OR SOON AFTER MIDNIGHT IN SOME AREAS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 359 PM EDT TUE MAY 7 2013 STACKED AND WEAKENING LOW PRESSURE WAS OVER THE CAROLINAS THIS AFTERNOON AND WAS MOVING NE. PRECIP ASSOCIATED WITH THE LOW WAS OVER WV AND ROTATING WESTWARD IN KY. MODELS SHOW IT TAKING A TURN TO THE SOUTHWEST AND THEN THE SOUTH THIS EVENING AS IT MOVES AROUND THE DEPARTING LOW. THIS PLACES THE GREATEST POTENTIAL FOR PRECIP IN OUR EASTERN COUNTIES THIS EVENING. THERE HAVE BEEN A FEW SPARSE LIGHTNING STRIKES TO OUR EAST...AND WITH MEAGER HEATING WHICH HAS TAKEN PLACE LOCALLY...WILL CARRY A SLIGHT CHANCE OF THUNDER HERE INTO THIS EVENING. AS HEATING IS LOST AND THE LOW SLOWLY MOVES AWAY...THERE SHOULD BE AN OVERALL DECREASE IN PRECIP OVERNIGHT. ON WEDNESDAY...HEATING SHOULD YIELD ENOUGH INSTABILITY TO CAUSE SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP OVER THE AREA ON THE EDGE OF THE DEPARTING LOW. WILL LOOK FOR A DIURNAL TREND...WITH THE ACTIVITY DYING OFF IN THE EVENING. THERE SHOULD BE MORE IN THE WAY OF CLEARING ON WEDNESDAY NIGHT AS MID/UPPER LEVEL RIDGING BUILDS IN. WITH RAIN LIKELY BEFORE THIS... FOLLOWED BY LIGHT WINDS...AND NO CHANGE IN SURFACE AIR MASS...THIS COULD RESULT IN QUITE A FOGGY NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 359 PM EDT TUE MAY 7 2013 MODELS ARE IN GOOD AGREEMENT THROUGH THE EXTENDED PORTION OF THE FORECAST. PESKY SLOW MOVING UPPER LEVEL LOW WILL FINALLY BE EXITING TO OUR NORTHEAST. SHORT WAVE RIDGING WILL BUILD IN BRIEFLY AT THE START OF THE PERIOD. BUT ANOTHER DISTURBANCE WILL MOVE QUICKLY INTO THE REGION FROM OUT OF THE SOUTHWESTERN CONUS TO FINISH OUT THE WEEK. THIS NEXT DISTURBANCE COMBINED WITH A LARGER...MORE ORGANIZED SYSTEM DROPPING SOUTHWARD OUT OF CANADA WILL KEEP UNSETTLED WEATHER IN THE FORECAST THROUGH MUCH OF THE UPCOMING WEEKEND. IN GENERAL... FORECAST SOUNDINGS ARE SHOWING ENOUGH SURFACE BASED INSTABILITY TO INCLUDE THUNDER WHENEVER POPS ARE MENTIONED THROUGH SATURDAY. THERE IS A DIURNAL FLAVOR TO SHOWER AND THUNDERSTORM ACTIVITY AS WELL. AM NOT CONVINCED SHOWER AND THUNDERSTORMS WILL BE AS PREVALENT AS RECENTLY ADVERTISED FOR THURSDAY. AFOREMENTIONED SHORT WAVE RIDGING APPEARS STRONG ENOUGH TO DEVELOP A CAP...SHOWING UP ON FORECAST SOUNDINGS THAT SHOULD HELP KEEP ACTIVITY LOW IF NOT AT A MINIMUM. A COUPLE OF THE MODELS...PARTICULARLY THE NAM DOES INDICATE A WEAK IMPULSE MOVING IN FROM THE WEST. QUESTION IS WILL IT BE STRONG ENOUGH TO LIFT OUT THE CAP. MODEL GUIDANCE IS SUGGESTING SLIGHT POPS. SO HAVE DECIDED TO SCALE BACK POPS FOR THURSDAY PROPER. LIKELY POPS APPEARS GOOD FOR FRIDAY...INTO THE BEGINNING OF THE WEEKEND. WILL TAPER POPS OFF QUICKLY SUNDAY AS A STRONG COLD FRONT CARRIES LINGERING SHOWERS OFF TO OUR EAST. OTHERWISE EXPECT NEAR NORMAL TEMPERATURES THROUGH FRIDAY. BUT SECOND MORE ORGANIZED SYSTEM THAT BRINGS THE STRONG COLD FRONT THROUGH OUR AREA SATURDAY NIGHT...OR EARLY SUNDAY MORNING WILL USHER IN ANOTHER ROUND OF MUCH COOLER AIR TO THE AREA TO FINISH OUT THE LONG TERM PORTION OF THE FORECAST. A SPECIAL NOTE THAT WITH HIGH PRESSURE CENTERED OVER OUR AREA MONDAY AND TUESDAY MORNINGS...CLEAR SKIES AND LIGHT WINDS...WE WILL HAVE TO KEEP AN EYE OUT FOR THE POTENTIAL FOR SOME PATCHY FROST AS OVERNIGHT LOWS WILL PROBABLY BOTTOM OUT IN THE MID 30S IN OUR TYPICALLY COLDER LOCATIONS BOTH MORNINGS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 133 AM EDT WED MAY 8 2013 A CHALLENGING AVIATION FORECAST THROUGH 13Z THIS MORNING. OBSERVATIONS FROM AROUND EASTERN KENTUCKY HAVE BEEN INDICATING AREAS OF FOG FORMING AROUND THE FORECAST AREA. THE FOG COULD BE LOCALLY DENSE AT TIMES. AS FAR AS THE AIRPORTS GO...JKL HAS BEEN SOCKED IN WITH LIFR FOG FOR THE PAST SEVERAL HOURS. LOZ AND SME...ON THE OTHER HAND...HAVE YET TO EXPERIENCE FOG FORMATION. THE CURRENT THINKING IS THAT JKL WILL LIKELY STAY SOCKED IN THROUGH 12Z BEFORE THE FOG LIFTS AND DISSIPATES AFTER THE SUN IS UP. LOZ AND SME ARE MUCH LESS CERTAIN. TYPICALLY SME GETS THEIR BEST FOG NIGHTS WHEN A LIGHT SOUTH WIND BLOWS ACROSS LAKE CUMBERLAND AND CARRIES A GOOD FETCH OF MOISTURE ACROSS THE SOMERSET AREA. AS OF TAF ISSUANCE...A LIGHT WESTERLY WIND WAS BLOWING AT SME...SO CONDITIONS THERE WERE NOT OPTIMAL FOR FOG. THEREFORE...WENT A BIT MORE OPTIMISTIC WITH THE CONDITIONS AT SME OVERNIGHT THAN THE PREVIOUS FORECAST INDICATED. DECIDED TO GO WITH MVFR VSBYS AND IFR CIGS AT SME. FOR LOZ...WENT A BIT MORE PESSIMISTIC THAN SME...AS FOG CONDITIONS AT LOZ ARE MORE IN LINE WITH TYPICAL FOG NIGHTS THAN AT SME. THAT BEING SAID...DECIDED TO GO WITH IFR CONDITIONS AT LOZ FOR THE TIME PERIOD 9 TO 12Z...WITH CONDITIONS RAPIDLY IMPROVING AFTER 12Z. EXPECTING SCATTERED TO NUMEROUS RAIN SHOWERS AND ISOLATED THUNDERSTORMS TO AFFECT THE TAF SITES BETWEEN 16 AND 23Z TODAY...AS AN AREA OF LOW PRESSURE SPINNING OFF TO OUR EAST BECOMES ACTIVE DURING THE PEAK HEATING HOURS. SHOWERS AND STORMS SHOULD DECREASE IN COVERAGE VERY QUICKLY AFTER 22Z TODAY...ONCE THE LOW BEGINS TO PULL OFF TO THE EAST AND DAYTIME HEATING IS LOST. MVFR CONDITIONS ARE EXPECTED WITH THE MORE INTENSE RAIN SHOWERS AND ANY THUNDERSTORMS TODAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...HAL LONG TERM...RAY AVIATION...AR
AREA FORECAST DISCUSSION
NWS GRAY ME
344 AM EDT WED MAY 8 2013 .SYNOPSIS... LOW PRESSURE WHICH HAS BEEN STALLED OVER THE SOUTH FOR THE LAST WEEK WILL WEAKEN AND LIFT NORTH INTO OUR AREA TODAY INTO THURSDAY. A STRONGER LOW MAY MOVE THROUGH LATER IN THE WEEKEND. A FRONT WILL STALL OVER THE REGION THIS WEEKEND...WITH WAVES OF LOW PRESSURE TRAVELING ALONG IT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOW CLOUDS AND FOG ENTERING THE REGION FROM THE GULF OF MAINE WILL BURN OFF THIS MORNING...HOWEVER...THIS MAY TAKE AN HOUR OR TWO LONGER THAN YESTERDAY. MEANWHILE...CLOUDS WILL BEGIN TO INCREASE FROM SOUTH TO NORTH TODAY AHEAD OF SLOW MOVING...AND WEAKENING CUTOFF LOW PRESSURE SYSTEM. ENOUGH SUPPORT TO ADD LOW CHC POPS TO THE FCST FOR THE AFTERNOON HOURS. LATEST HRRR RUN BRINGS A BAND OF SHOWERS INTO SW NH AROUND 19 OR 20Z. MAX TEMPS WILL ONCE AGAIN APPROACH 80 DEGRESS WELL IN TO THE INTERIOR TODAY...WITH MAINLY 60S ALONG THE COAST. USED A BLEND OF MAV/MET MOS NOS FOR AFTERNOON HIGHS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... AREAS OF FOG WILL REDEVELOP ONCE AGAIN TONIGHT. SOUTHERLY FLOW OFF THE BRINK AS WELL AS THE APPROACH OF THE UPPER LEVEL TROUGH WILL ALLOW FOR SCT SHOWER ACTIVITY OVER ALL PTNS OF ME/NH. PATCHY DRIZZLE WILL BE PSBL ALG AND NEAR THE COASTLINE AS WELL. THE PATTERN WILL REMAIN UNSETTLED ON THURSDAY AS THE UPPER TROUGH SLOWLY ENTERS THE REGION. HIGHEST POS WILL BE IN THE MTNS OF MAINE. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A SLOW MOVING FRONT WILL REMAIN BANKED UP TO OUR NORTHWEST THURSDAY NIGHT. ALL MODELS CONTINUE TO SHOW A WEAK WAVE TRAVELING ALONG THIS FEATURE...TRIGGERING MORE SCT SHOWERS ACROSS THE REGION. THE FRONT BECOMES NEARLY STATIONARY OVER THE WEEKEND...WITH DRIER AIR NOT ADVECTING INTO THE REGION UNTIL SUNDAY. THE FRONT WILL MOVE OFF THE COAST BY MONDAY...ALLOWING MUCH DRIER AND COOLER AIR TO FINALLY ENTER THE REGION. GUSTY WINDS WILL ACCOMPANY THE COLD AIR ADVECTION ON MONDAY. ANOTHER WEATHER DISTURBANCE WILL BRING THE THREAT OF SHOWERS DURING THE MIDWEEK PERIOD. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM... CONDITIONS ARE EXPECTED TO BE IFR WITH LOCALLY LIFR IN FOG AND LOW CLOUDS ALONG COASTAL AREAS AND JUST INLAND FROM THE COAST EARLY THIS MORNING. THE FOG WILL BE MORE WIDESPREAD TONIGHT INTO THURSDAY. LONG TERM...MVFR CONDITIONS ARE EXPECTED AT TAF SITES AS AN UPPER LOW BRINGS SHOWERS TO THE REGION. SHOWERS WILL REDEVELOP ON FRIDAY AHEAD OF A STRONG COLD FRONT. INSTABILITY SHOWERS WILL PERSIST INTO THIS WEEKEND BEHIND THE COLD FRONT. && .MARINE... SHORT TERM...WINDS AND SEAS WILL BE BELOW SCA. PATCHY FOG IS EXPECTED ACROSS THE WATERS TODAY WITH AREAS OF FOG TONIGHT INTO THURSDAY. LONG TERM... WIND GUSTS WILL INCREASE FRIDAY AFTERNOON AS A COLD FRONT APPROACHES NORTHERN NEW ENGLAND. NO HEADLINES ARE EXPECTED. WINDS MAY BECOME GUSTY BEHIND A COLD FRONT EARLY NEXT WEEK. && .FIRE WEATHER... MORE HUMID AIR WILL CONTINUE TO FILTER INTO SOUTHERN AREAS TODAY. HOWEVER...NORTHERN AREAS WILL CONTINUE TO BE DRY. CLOUDS WILL INCREASE AND THICKEN LATER TODAY...ALLOWING SCATTERED SHOWERS TO ENTER THE REGION. SCATTERED SHOWERS WILL CONTINUE RIGHT THROUGH THE WEEKEND...WITH MORE WIDESPREAD SHOWER ACTIVITY POSSIBLE FRIDAY NIGHT. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
123 AM EDT WED MAY 8 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 403 PM EDT TUE MAY 7 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW BLOCKY FLOW ACROSS THE CONUS TO THE S OF PROGRESSIVE FLOW ACROSS CNTRL CANADA. A NARROW RIDGE EXTENDS FROM SRN BRITISH COLUMBIA/NRN WA E ACROSS THE UPPER GREAT LAKES TO NEW ENGLAND. FARTHER S...CLOSED MID LEVEL LOWS WERE LOCATED OVER CA/SRN NV...OVER SD AND OVER THE SE CONUS. WITH THE UPPER GREAT LAKES STILL UNDER THE RIDGE...IT`S BEEN ANOTHER PLEASANT EARLY MAY DAY ACROSS UPPER MI AS DEEP VERY DRY COLUMN (NOTE 12Z KGRB/KAPX SOUNDINGS) IS ALLOWING FOR ABUNDANT SUNSHINE. SOME VERY HIGH BASED CU HAS DEVELOPED OVER THE W WITH A FEW ALONG THE LAKE BREEZE BOUNDARY OVER THE E. VERY DEEP MIXING HAS INTO THE DRY AIR ALOFT HAS RESULTED IN DWPTS CRASHING OVER THE LAST FEW HRS. RH HAS PLUNGED INTO THE 10-20PCT RANGE AT A NUMBER OF LOCATIONS ACROSS THE CNTRL AND E. LAKE BREEZES HAVE AGAIN DEVELOPED ACROSS THE BOARD...AND WHILE IT`S CHILLY ALONG LAKE SUPERIOR WITH TEMPS IN THE 40S JUST LIKE YESTERDAY...THE COOLING IS AGAIN VERY WEAK ALONG MOST OF THE LAKE MI SHORELINE. INLAND...TEMPS HAVE SOARED WELL INTO THE 70S. NARROW RIDGE OVER THE UPPER LAKES IS IN THE PROCESS OF BREAKING DOWN AS MODEST AMPLIFICATION OF THE FLOW IS UNDERWAY ACROSS CNTRL/ERN CANADA IN ASSOCIATION WITH VIGOROUS SHORTWAVE MOVING ACROSS NRN MANITOBA TO HUDSON BAY. MUCH STRONGER AMPLIFICATION WILL OCCUR LATER THIS WEEK AS TROF SHARP TROF DEVELOPS S INTO THE GREAT LAKES. COLD FRONT ASSOCIATED WITH NRN MANITOBA SHORTWAVE IS CURRENTLY RUNNING FROM NRN MANITOBA TO MT. WITH FRONT STILL WELL W OF THE AREA THRU THE NIGHT AND WITH DRY AIR MASS LINGERING...ANOTHER MAINLY CLEAR NIGHT IS ANTICIPATED. OVERALL...LOW-LEVEL WINDS WILL BE LIGHT AGAIN...AND THERE IS LITTLE CHANGE IN PRECIPITABLE WATER... SUGGESTING MIN TEMPS SHOULD BE SIMILAR TO LAST NIGHT. HOWEVER...WITH AIR MASS CONTINUING TO MODERATE WITH STRONG HEATING THIS AFTN... WOULD EXPECT MINS GENERALLY TO BE A FEW DEGREES HIGHER THAN LAST NIGHT. DEVELOPING LIGHT S TO SW FLOW WILL BEGIN TO STIR IN THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR...SO MINS THERE WILL PROBABLY BE HIGHEST. MIN TEMPS SHOULD RANGE FROM THE 30S INLAND TO THE LWR 40S ALONG LAKE SUPERIOR. ON WED...APPROACHING COLD FRONT SHOULD REACH WRN/NRN LAKE SUPERIOR LATE IN THE AFTN/EARLY EVE. SOME OF THE MOISTURE NOTED ON TODAYS 12Z KMPX/KINL SOUNDINGS SHOULD ADVECT E AND NE AHEAD OF THE APPROACHING COLD FRONT. HOWEVER...WITH LIGHT WINDS AND LITTLE ADVECTION AT THE LOW-LEVELS...DRIER AIR WILL LIKELY LINGER UNDERNEATH THE MOISTENING OCCURRING HIGHER UP. IN THE END...THIS WILL WORK TO MINIMIZE SHRA THREAT WED. HOWEVER...WITH MLCAPE UPWARDS OF A FEW HUNDRED J/KG... CAN`T RULE OUT A FEW HIGH BASED SHRA OVER THE W WHERE AFTN LAKE BREEZE WILL HELP TO POOL LOW-LEVEL MOISTURE AND PROVIDE A LOW-LEVEL FORCING MECHANISM. OTHERWISE...IT WILL BE ANOTHER WARM DAY ON PAR WITH WHAT IS GOING ON THIS AFTN. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 426 PM EDT TUE MAY 7 2013 WE WILL BEGIN WEDNESDAY NIGHT WITH A SERIES OF DISTURBANCES SCATTERED ACROSS THE UNITED STATES. THE MAIN FEATURES INFLUENCING OUR WEATHER OVER THE NEXT SEVERAL DAYS INCLUDE THE LARGE SCALE 500MB TROUGH STRETCHED ACROSS MUCH OF CANADA...EXTENDING ACROSS MN/AND IA AT 00Z THURSDAY...WITH AN ELONGATED SFC TROUGH SET UP FROM AROUND IMT THROUGH ERY AND NORTHEASTWARD. THE TROUGH WILL CONTINUE TO SINK SOUTHEAST OF THE CWA OVERNIGHT. THE NON-ECMWF SOLUTIONS CONTINUE TO HIT THE NEXT SHORTWAVE A BIT HARDER...WITH 0.2-0.4IN OF QPF OVER MUCH OF THE AREA. WILL CONTINUE THE HIGH CHANCE POPS...WITH A CAVEAT. IF WE GET LESS PRECIP THAN ANTICIPATED...OR IT ENDS UP BEING SLOWER...THE DOWNSLOPE AREAS FROM ESCANABA THROUGH MANISTIQUE...AND EAST COULD BE QUITE A BIT LOWER /CURRENTLY FCST TO BOTTOM OUT 35-45 PERCENT/. EXPECT THE SLOW MOTION 500MB TROUGH TO BE CENTERED OVER THE LAKE SUPERIOR AND UPPER MI AT 00Z FRIDAY...WITH COOL HIGH PRESSURE BUILDING IN AT THE SFC. 25-35KT 900-925MB WINDS ARE EXPECTED THURSDAY NIGHT. THERE IS A SLIGHT CONCERN FOR FIRE CONCERNS...IF WE HAVE POOR RH RECOVERIES...AS LOTS OF DRY AIR SLIDES IN FOR FRIDAY. WENT WITH RH VALUES FALLING TO 25-35PERCENT...BUT WOULD NOT BE SURPRISED TO SEE LOWER VALUES GIVEN THE VERY DRY AIR WITH MIXED DEWPOINTS IN THE TEENS OR LOWER CENTRAL. ZONAL FLOW WILL TAKE HOLD FRIDAY AFTERNOON/EVENING AHEAD OF YET ANOTHER TROUGH ROTATING AROUND THE NORTHERN CANADIAN LOW. THIS ONE LOOKS TO BE PARTICULARLY INTERESTING...AS IT INTENSIFIES INTO A CLOSED LOW OVER EASTERN MANITOBA AND WESTERN ONTARIO FRIDAY NIGHT. THERE IS SOME UNCERTAINTY TO THE POSITION OF THE 500MB LOW AT 00Z SUNDAY...WHICH WILL LIKELY BE SOMEWHERE BETWEEN WESTERN UPPER MI TO CENTRAL ONTARIO. THE 07/00Z ECMWF KEPT THE TREND OF BEING THE DEEPEST WITH THE LOW...RUSHING COLD AIR IN FROM THE WEST DURING THE DAY SATURDAY. KEPT A GOOD CHANCE OF MIXED PRECIP IN THE FCST FROM SATURDAY THROUGH SUNDAY...WITH LITTLE TO NO REAL ACCUMULATION EXPECTED AS THE BULK OF THE MOISTURE SHOULD BE EAST OF THE CWA BY THE TIME THE -6 TO -10C AIR FILTERS IN. THE ECMWF REMAINS THE COOLEST WITH THE SYSTEM. FARTHER OUT...FEW CHANGES WERE MADE TO OUR MODERATING FCST FOR THE START OF THE NEXT WORK WEEK...WITH W-SW WINDS AND DRY WX FIGURED MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 122 AM EDT WED MAY 8 2013 EXPECT VFR CONDITIONS AND LIGHT WINDS AT ALL 3 SITES TONIGHT INTO WED MORNING WITH DRY HI PRES DOMINATING. APPROACHING COLD FRONT FM SRN CANADA COULD BRING AN INCREASE IN MID CLOUDS LATE WED AFTERNOON INTO WED EVENING IN ITS WAKE BUT OTHERWISE VFR CONDITIONS WILL PREVAIL. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 403 PM EDT TUE MAY 7 2013 HIGH PRESSURE WILL CONTINUE TO PRODUCE LIGHT WINDS THRU WED... BUT A COLD FRONT MOVING ACROSS LAKE SUPERIOR LATE WED AFTN AND EVENING WILL LEAD TO INCREASING NORTH-NORTHEAST WINDS PEAKING IN THE 15-25KT RANGE WED NIGHT INTO THU MORNING. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR FRI AND DIMINISH THE WINDS. A STRONGER COLD FRONT WILL SLIDE ACROSS THE UPPER LAKES FRI NIGHT AND SHIFT WINDS TO THE NW AT 20-30KTS SAT. THESE STRONGER WINDS WILL CONTINUE INTO SAT NIGHT BEFORE GRADUALLY DIMINISHING FROM W TO E ON SUN. && .HYDROLOGY... ISSUED AT 426 PM EDT TUE MAY 7 2013 WE WILL MONITOR LOCAL RIVER LEVELS...BUT CONTINUE TO SEE FALLING VALUES ACROSS MUCH OF THE REGION AS THE SNOW PACK FALLS TO NEAR ZERO WITH OUR SERIES OF ABOVE NORMAL TEMPERATURES. THE LATEST SNOW DEPTH OBSERVATIONS /FROM EARLIER THIS MORNING AROUND 8AM HAS IRONWOOD WITH NO SNOW LEFT ON THE GROUND...AND ATLANTIC MINE WITH 4IN. A FEW POCKETS OF HIGHER AMOUNTS ARE LIKELY ACROSS THE KEWEENAW...AND THE HIGHEST ELEVATIONS OF NORTHERN MARQUETTE COUNTY. THE TRICKY LINGERING ISSUES AT AT TRRM4 /TRAP ROCK - LAKE LINDEN/ AND BESM4 /BESSEMER - BLACK RIVER/. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD WARNINGS AND ADVISORIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...VOSS MARINE...ROLFSON HYDROLOGY...KF
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
331 AM CDT WED MAY 8 2013 .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 329 AM CDT WED MAY 8 2013 LITTLE CHANGE IN THINKING THIS MORNING SINCE PREVIOUS FORECAST. THE PRIMARY CHALLENGE THIS MORNING IS TIMING THE START OF PRECIP TODAY. IF CURRENT RADAR TRENDS HOLD TRUE...THE SHOWERS CURRENTLY OVER KANSAS WILL REACH THE WESTERN-MOST PORTIONS OF OUR CWFA BETWEEN 16-17Z. THIS TIMING AGREES WELL WITH MOST SHORT RANGE MODEL GUIDANCE INCLUDING THE HRRR AND 4KM NCEP WRF. SHOULD SEE INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTHEAST MISSOURI TONIGHT AS THE COMPACT SHORTWAVE OVER SOUTH DAKOTA DRIFTS SOUTHEAST INTO IOWA. THIS FORCES THE LOW LEVEL JET TO STRENGTHEN OVER THE AREA CAUSING AMPLE LOW LEVEL MOISTURE CONVERGENCE OVER REGION WHICH SHOULD KEEP PRECIPITATION GOING OVER CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS FOR MUCH OF THE NIGHT. THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ACROSS THE REST OF THE AREA ON THURSDAY AS DAYTIME HEATING DESTABILIZES THE ATMOSPHERE AND THE SHORTWAVE CONTINUES TO DIG INTO THE MID-MISSISSIPPI VALLEY. STRONG STORMS ARE POSSIBLE...THO CONDITIONS APPEAR MARGINAL FOR SEVERE WITH 1000-1200 J/KG CAPE BUT ONLY 15-20KTS OF SHEAR. IF THERE ARE SEVERE STORMS WOULD THINK THE PRIMARY THREAT WILL BE DAMAGING WINDS...HAIL THREAT SEEMS LIMITED DUE TO SMALL CAPE VALUES IN THE HAIL GROWTH ZONE. SHOULD SEE PRECIP DECREASE FROM NORTHWEST TO SOUTHEAST LATE THURSDAY NIGHT INTO THE PRE-DAWN HOURS OF FRIDAY MORNING. CANNOT RULE OUT SCATTERED SHOWERS AND THUNDERSTORMS GENERALLY ALONG AND SOUTH OF I-70 AGAIN FRIDAY...BUT THINK THE THREAT FOR ORGANIZED CONVECTION WILL BE MINIMAL. TEMPERATURE TRENDS THROUGH FRIDAY WILL BE HIGHLY DEPENDENT ON PRECIPITATION. GENERALLY STUCK PRETTY CLOSE TO THE MIDDLE OF THE ROAD OF GUIDANCE NUMBERS. CARNEY .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 329 AM CDT WED MAY 8 2013 GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH THE SATURDAY THROUGH MONDAY PERIOD. ANOTHER SHORTWAVE WILL DIG SOUTHEAST OUT OF CANADA INTO THE GREAT LAKES REGION AMPLIFYING THE FLOW ACROSS THE U.S. THIS WILL PUSH A COLD FRONT SOUTH THROUGH THE MISSISSIPPI VALLEY ON SATURDAY. A STRONG CANADIAN HIGH WILL DROP INTO THE ARE BEHIND THE FRONT BRINGING US ANOTHER SHOT OF BELOW NORMAL TEMPERATURES. GFS AND ECMWF CONTINUE TO PRODUCE VERY LIGHT QPF ACROSS PARTS OF THE AREA ON SATURDAY AS THE FRONT MOVES THROUGH SO HAVE KEPT CHANCE POPS IN THE FORECAST. 850MB TEMPS DROP TO NEAR ZERO SUNDAY SO HAVE CONTINUED THE DOWNWARD TREND FOR HIGHS...UNDERCUTTING GUIDANCE BY A FEW DEGREES. MONDAY MORNING WILL LIKELY BE THE COLDEST OF THE BUNCH...WITH POSSIBLY THE LAST FROST OF THE SEASON. SHOULD SEE A NICE WARM UP MONDAY AFTERNOON AND TUESDAY AS AN UPPER LEVEL RIDGE BUILDS OVERHEAD AND SOUTHWEST FLOW RETURNS TO THE AREA. CARNEY && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1155 PM CDT TUE MAY 7 2013 HAVE ADDED AREAS OF MVFR FOG TO STL AREA TAFS DUE TO NARROWING TEMP/DEWPOINT SPREADS...WITH TEMPO IFR VSBYS AT FOG PRONE SUS AND CPS. ELSEWHERE...AMS IS MUCH DRIER SO NOT EXPECTING MUCH OF A FOG THREAT.... AND AS SURFACE RIDGE WORKS ACROSS AREA CLEAR SKIES AND LIGHT WINDS WILL PREVAIL. WE COULD SEE A BIT OF DIURNALLY DRIVEN CU POP AT MID MORNING...BUT PRIMARY CLOUDINESS ON WEDNESDAY SHOULD BE MID AND HIGH LEVEL CLOUDS THAT WILL SLOWLY WORK FROM WEST TO EAST ACROSS THE AREA. STILL BELIEVE THAT SIGNIFICANT PRECIP WILL HAVE A HARD TIME MAKING TOO MUCH EWD PROGRESS...SO FOR THIS SET HAVE CONTINUED WITH THE IDEA OF VCSH FROM A MID CLOUD DECK WORKING INTO UIN AND COU BY MID AFTERNOON...AND INTO THE STL AREA BY MID EVENING. SPECIFICS FOR KSTL...HAVE ADDED MVFR FOG AT STL DUE TO NARROWING TEMP/DEWPOINT SPREADS...BUT THINK THAT THE LOWER IFR VSBYS WILL BE CONFINED TO RIVER VALLEY LOCATIONS. OTHERWISE...LOOKING FOR CLEAR SKIES OVERNIGHT....GIVING WAY TO A BIT OF CU BY MID MORNING AND THEN A SLOW INCREASE OF MID AND HIGH LEVEL VFR CLOUDS. AS MENTIONED ABOVE...THINK PRECIP WILL BE SOMEWHAT SLOW TO SPREAD EAST...TO HAVE ADDED VCSH FROM VFR MID CLOUD DECK BY WEDNESDAY EVENING. TRUETT && .PRELIMINARY POINT TEMPS/POPS... SAINT LOUIS 83 62 78 60 / 10 40 60 60 QUINCY 78 59 73 54 / 40 80 80 60 COLUMBIA 78 59 74 57 / 40 80 70 60 JEFFERSON CITY 79 60 75 58 / 40 70 60 60 SALEM 79 58 78 61 / 10 10 60 60 FARMINGTON 79 59 77 59 / 20 20 50 60 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY. && .NEAR TERM /THROUGH THURSDAY NIGHT/... AS OF 310 AM WEDNESDAY... ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY. FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND WRN PIEDMONT. MID LEVEL DPVA COMBINED WITH AN AREA OF ENHANCED MOISTURE AND LOW LEVEL CONVERGENCE IS SUPPORTING A BATCH OF SHOWERS TRACKING NE THROUGH CENTRAL NC EARLY THIS MORNING. THE MID-UPPER LEVEL LOW THAT HAS PLAGUED THE REGION FOR DAYS IS LOCATED AROUND RNK EARLY THIS MORNING... AND IS EXPECTED TO DRIFT TOWARD THE NNE ALONG THE ERN SLOPES OF THE APPALACHIANS INTO PA TONIGHT. ABOVE-NORMAL PRECIP WATER WILL CONTINUE TO ROTATE ABOUT THE NEARLY STACKED CYCLONE... AND MODELS SHOW OVERALL PRECIP WATER INCREASING FROM JUST UNDER AN INCH THIS MORNING TO NEARLY 1.2 INCHES -- CLOSE TO 150% OF NORMAL -- OVER CENTRAL/ERN NC THIS AFTERNOON. WITH LOW LEVEL WARM AIR ADVECTION AND THE POCKET OF SLIGHTLY COOLER MID LEVEL TEMPS OVER NRN/WRN NC... EXPECT THE COLUMN TO DESTABILIZE BY AFTERNOON... AND BOTH THE NAM AND RAP MODELS SHOW MLCAPE INCREASING TO 600-1200 J/KG LATER TODAY SPREADING IN FROM THE SW. AS THE LOW ALOFT LIFTS AWAY FROM NC... MID LEVEL FLOW STRENGTHENS QUICKLY FROM LESS THAN 20 KTS EARLY THIS MORNING TO 35-40 KTS FROM THE W AND WNW THIS AFTERNOON... AND THIS SHOULD FOSTER STORM ORGANIZATION DESPITE THE MARGINAL INSTABILITY. DYNAMIC SUPPORT FROM VORTICITY LOBES ROTATING AROUND THE LOW AS WELL AS A QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A NORTHWESTERLY 50-KT UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD ALSO ENCOURAGE STORM DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED SHOWERS FINISH THEIR JOURNEY THROUGH CENTRAL NC THIS MORNING... EXPECTED SCATTERED SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE HIGHER TERRAIN OF NW NC INTO THE TRIAD REGION... THEN INCREASING IN COVERAGE AS THEY PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC DURING THE AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC WRF. GIVEN THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD BECOME STRONG WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH WILL DEPEND ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND THIS IN TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD COVER PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE CLOUDS AND SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND QUICKLY RISING CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS. EXPECT HIGHS FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE AND FACTORING IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE MEAGER DYNAMIC SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID LEVEL LOW... AND WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL AFTER NIGHTFALL ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL FLOW AND DRYING... SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT... FOLLOWED BY GRADUAL CLEARING WEST TO EAST. LOWS 53-58. FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 315 AM WEDNESDAY... SPLIT FLOW PATTERN OVER THE CONUS LATE THIS WEEK WILL BECOME DOMINATED BY THE NORTHERN STREAM BY THIS WEEKEND AS A STRONG SHORTWAVE BEGINS TO CARVE OUT A DEEP TROUGH OVER THE EASTERN US. AHEAD OF THIS SYSTEM...RIDGING OVER OUR REGION WILL WEAKEN AS A LEAD SHORTWAVE MOVES THROUGH THE MIDWEST STATES. THE ASSOCIATED FRONTAL ZONE WILL MOVE SLOWLY TO THE EAST AND APPROACH THE APPALACHIANS SATURDAY. THE MORE UNSTABLE WARM SECTOR AIRMASS WILL BE WEST OF THE MOUNTAINS ON FRIDAY...ALTHOUGH FORECAST SOUNDINGS SUGGEST MLCAPE MAY REACH 500-1000 J/KG FRIDAY AFTERNOON AS THE UPPER RIDGE WEAKENS. DEEP LAYER SOUTHWESTERLY FLOW SHOULD BE RELATIVELY WEAK...MAKING IT DIFFICULT FOR MUCH MORE THAN A FEW ISOLATED STORMS TO MOVE INTO THE WESTERN PIEDMONT. FRIDAY WILL BE THE WARMEST DAY OF THE PERIOD WITH PARTLY CLOUDY TO MOSTLY SUNNY SKIES. LOW LEVEL THICKNESSES SURPASSING 1390M AND A SOUTHWESTERLY WIND SUGGEST HIGHS IN THE LOW TO MID 80S. LOWS FRIDAY NIGHT IN THE LOW TO MID 60S. GRADUAL HEIGHT FALLS AHEAD OF THE AFOREMENTIONED UPPER TROUGH MOVING SOUTH OUT OF CANADA WILL HELP TO SHARPEN THE LEE TROUGH SATURDAY AS A THE COLD FRONT APPROACHES FROM THE WEST. WITH WEAK TO MODERATE INSTABILITY POSSIBLE...DEPENDING ON THE AMOUNT REGIONAL CLOUD COVER SATURDAY MORNING....AND DEEP LAYER SHEAR INCREASING TO AROUND 30KT...THERE WILL BE A BETTER CHANCE OF STRONG STORMS SATURDAY AFTERNOON. HIGHS 76-83 WEST TO EAST. EVEN WITH THE LOSS OF HEATING SATURDAY NIGHT...SOME CONVECTION SHOULD STILL BE ABLE TO PERSIST AS THE LEAD FRONTAL ZONE MOVES INTO CENTRAL NC. WILL MAINTAIN A CHANCE POP THROUGH THE OVERNIGHT HOURS...WITH LOWS IN THE LOW TO MID 60S. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 315 AM WEDNESDAY... THE COLD FRONT CROSSING THE AREA SATURDAY NIGHT SHOULD EFFECTIVELY SHIFT TO THE COASTAL PLAIN SUNDAY MORNING...WHILE A SECONDARY AND STRONGER POLAR FRONT SWINGS INTO THE AREA FROM THE NORTHWEST. CHANCES OF PRECIP WILL BE PRIMARILY FOCUSED OVER THE COASTAL PLAIN WHERE ANY APPRECIABLE INSTABILITY WOULD BE MORE LIKELY. HIGHS BEGIN THEIR MORE SIGNIFICANT DOWNWARD TREND SUNDAY AND PARTICULARLY MONDAY AS THE AFOREMENTIONED POLAR FRONT CROSSES THE AREA AND A DEEP UPPER TROUGH DEVELOPS OVER THE EASTERN US. HIGHS IN THE MID 70S SUNDAY WILL FALL WELL BELOW NORMAL INTO THE MID TO UPPER 60S MONDAY AND TUESDAY. THERE IS MEDIUM TO HIGH CONFIDENCE IN THESE BELOW NORMAL TEMPS AND DRY CONDITIONS DURING THE FIRST PART OF NEXT WEEK.. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 1245 AM WEDNESDAY... LIKELIHOOD IS INCREASING THAT MOST CENTRAL NC TAF SITES WILL SEE VFR CIGS/VSBYS THROUGH THIS MORNING... ALTHOUGH A BRIEF PERIOD OF IFR VSBYS IS POSSIBLE AT INT/GSO NEAR AND JUST BEFORE DAYBREAK. CONSIDERABLE CONVECTIVE-DEBRIS CLOUDINESS FROM YESTERDAY`S SHOWERS AND STORMS ARE BASED ABOVE 5 THOUSAND FT AGL AND SHOULD CONTINUE TO OVERSPREAD INT/GSO/RDU THROUGH THE NIGHT... EVENTUALLY REACHING FAY/RWI AS WELL LATER TODAY. DESPITE THE OTHERWISE-FAVORABLE CONDITIONS OF LIGHT WINDS AND HIGH HUMIDITY WITH A DAMP GROUND... THE PRESENCE OF THESE CLOUDS WILL LOWER THE CHANCES OF FOG AND IFR/LIFR EARLY THIS MORNING. FAY WILL SEE THE FEWEST OF THESE HIGHER-BASED CLOUDS LATER THAN OTHER SITES... SO FAY HAS THE BEST CHANCE (BUT STILL LOW) OF SEEING LOW STRATUS DEVELOP. OTHERWISE... EXPECT VFR CONDITIONS TO DOMINATE MUCH OF TODAY INTO TONIGHT. SCATTERED SHOWERS AND STORMS ARE EXPECTED TO AFFECT INT/GSO MAINLY FROM 16Z-20Z... RDU MAINLY FROM 17Z-21Z... AND RWI/FAY MAINLY FROM 19Z-23Z... AND A PERIOD OF MVFR-IFR CIGS/VSBYS IN AND NEAR SHOWERS/STORMS IS LIKELY. LOOKING BEYOND 06Z TONIGHT: VFR CLOUDS ARE EXPECTED TO CLEAR OUT LATE... AND SUB-VFR FOG IS POSSIBLE TONIGHT PRIMARILY 08Z-12Z AT ALL SITES. OTHERWISE VFR CONDITIONS SHOULD DOMINATE INTO SATURDAY MORNING. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF SUB-VFR CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY. && .NEAR TERM /THROUGH THURSDAY NIGHT/... AS OF 310 AM WEDNESDAY... ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY. FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND WRN PIEDMONT. MID LEVEL DPVA COMBINED WITH AN AREA OF ENHANCED MOISTURE AND LOW LEVEL CONVERGENCE IS SUPPORTING A BATCH OF SHOWERS TRACKING NE THROUGH CENTRAL NC EARLY THIS MORNING. THE MID-UPPER LEVEL LOW THAT HAS PLAGUED THE REGION FOR DAYS IS LOCATED AROUND RNK EARLY THIS MORNING... AND IS EXPECTED TO DRIFT TOWARD THE NNE ALONG THE ERN SLOPES OF THE APPALACHIANS INTO PA TONIGHT. ABOVE-NORMAL PRECIP WATER WILL CONTINUE TO ROTATE ABOUT THE NEARLY STACKED CYCLONE... AND MODELS SHOW OVERALL PRECIP WATER INCREASING FROM JUST UNDER AN INCH THIS MORNING TO NEARLY 1.2 INCHES -- CLOSE TO 150% OF NORMAL -- OVER CENTRAL/ERN NC THIS AFTERNOON. WITH LOW LEVEL WARM AIR ADVECTION AND THE POCKET OF SLIGHTLY COOLER MID LEVEL TEMPS OVER NRN/WRN NC... EXPECT THE COLUMN TO DESTABILIZE BY AFTERNOON... AND BOTH THE NAM AND RAP MODELS SHOW MLCAPE INCREASING TO 600-1200 J/KG LATER TODAY SPREADING IN FROM THE SW. AS THE LOW ALOFT LIFTS AWAY FROM NC... MID LEVEL FLOW STRENGTHENS QUICKLY FROM LESS THAN 20 KTS EARLY THIS MORNING TO 35-40 KTS FROM THE W AND WNW THIS AFTERNOON... AND THIS SHOULD FOSTER STORM ORGANIZATION DESPITE THE MARGINAL INSTABILITY. DYNAMIC SUPPORT FROM VORTICITY LOBES ROTATING AROUND THE LOW AS WELL AS A QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A NORTHWESTERLY 50-KT UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD ALSO ENCOURAGE STORM DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED SHOWERS FINISH THEIR JOURNEY THROUGH CENTRAL NC THIS MORNING... EXPECTED SCATTERED SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE HIGHER TERRAIN OF NW NC INTO THE TRIAD REGION... THEN INCREASING IN COVERAGE AS THEY PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC DURING THE AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC WRF. GIVEN THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD BECOME STRONG WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH WILL DEPEND ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND THIS IN TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD COVER PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE CLOUDS AND SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND QUICKLY RISING CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS. EXPECT HIGHS FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE AND FACTORING IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE MEAGER DYNAMIC SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID LEVEL LOW... AND WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL AFTER NIGHTFALL ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL FLOW AND DRYING... SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT... FOLLOWED BY GRADUAL CLEARING WEST TO EAST. LOWS 53-58. FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH && .SHORT TERM / /... AS OF 245 PM TUESDAY... TO BE UPDATED. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 110 PM TUESDAY... AROUND REX BLOCKING OVER THE WESTERN US...SPLIT FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY WILL GRADUALLY TRANSITION TOWARD NORTHERN STREAM DOMINANCE OWING TO THE AMPLIFICATION OF A VORTEX INVOF THE SOUTHERN TIP OF HUDSON BAY DURING THE WEEKEND AND EARLY NEXT WEEK. THE PASSAGE OF A LEAD SHORTWAVE TROUGH THROUGH THE NORTHEAST ON FRIDAY WILL FIRST SHARPEN A LEE TROUGH OVER WESTERN NC FRI AFTERNOON...THEN PROPEL A LEAD SURFACE COLD FRONT INTO THE APPALACHIANS AND CAROLINAS ON SATURDAY. A STRONGER POLAR FRONT ATTENDING THE AFOREMENTIONED HUDSON BAY VORTEX WILL THEN OVERTAKE THE LEAD FRONTAL ZONE AND SWEEP ACROSS CENTRAL NC SUNDAY...WITH CONTINENTAL POLAR HIGH PRESSURE BUILDING IN FOR MON-TUE. AS SUCH...THE PREVIOUS FORECAST OF CHANCE OF SHOWERS AND STORMS OVER THE WESTERN PIEDMONT FRI...TRANSITIONING TO SOLID CHANCE AREA-WIDE SATURDAY THROUGH SUNDAY NEEDS LITTLE ADJUSTMENT. ANY ORGANIZED CONVECTIVE MODE WOULD BE FAVORED DURING THE WEEKEND...WHEN WARM SECTOR MID LEVEL FLOW WILL BE MAXIMIZED AROUND 40-50 KTS...WITH OTHERWISE DISORGANIZED/PULSE MODES UNTIL THEN. TEMPERATURES WILL CONSEQUENTLY BE VARIABLE...PEAKING IN THE MIDDLE 80S FRI...AND SAT IN THE COASTAL PLAIN...TRENDING TO THE MID-UPPER 60S IN THE CP HIGH PRESSURE MON...AND REBOUNDING TO AROUND 70 DEGREES BY TUE. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 1245 AM WEDNESDAY... LIKELIHOOD IS INCREASING THAT MOST CENTRAL NC TAF SITES WILL SEE VFR CIGS/VSBYS THROUGH THIS MORNING... ALTHOUGH A BRIEF PERIOD OF IFR VSBYS IS POSSIBLE AT INT/GSO NEAR AND JUST BEFORE DAYBREAK. CONSIDERABLE CONVECTIVE-DEBRIS CLOUDINESS FROM YESTERDAY`S SHOWERS AND STORMS ARE BASED ABOVE 5 THOUSAND FT AGL AND SHOULD CONTINUE TO OVERSPREAD INT/GSO/RDU THROUGH THE NIGHT... EVENTUALLY REACHING FAY/RWI AS WELL LATER TODAY. DESPITE THE OTHERWISE-FAVORABLE CONDITIONS OF LIGHT WINDS AND HIGH HUMIDITY WITH A DAMP GROUND... THE PRESENCE OF THESE CLOUDS WILL LOWER THE CHANCES OF FOG AND IFR/LIFR EARLY THIS MORNING. FAY WILL SEE THE FEWEST OF THESE HIGHER-BASED CLOUDS LATER THAN OTHER SITES... SO FAY HAS THE BEST CHANCE (BUT STILL LOW) OF SEEING LOW STRATUS DEVELOP. OTHERWISE... EXPECT VFR CONDITIONS TO DOMINATE MUCH OF TODAY INTO TONIGHT. SCATTERED SHOWERS AND STORMS ARE EXPECTED TO AFFECT INT/GSO MAINLY FROM 16Z-20Z... RDU MAINLY FROM 17Z-21Z... AND RWI/FAY MAINLY FROM 19Z-23Z... AND A PERIOD OF MVFR-IFR CIGS/VSBYS IN AND NEAR SHOWERS/STORMS IS LIKELY. LOOKING BEYOND 06Z TONIGHT: VFR CLOUDS ARE EXPECTED TO CLEAR OUT LATE... AND SUB-VFR FOG IS POSSIBLE TONIGHT PRIMARILY 08Z-12Z AT ALL SITES. OTHERWISE VFR CONDITIONS SHOULD DOMINATE INTO SATURDAY MORNING. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF SUB-VFR CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...VINCENT/MWS LONG TERM...MWS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1237 AM CDT WED MAY 8 2013 .UPDATE... ISSUED AT 1237 AM CDT WED MAY 8 2013 LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW THE UPPER LEVEL LOW CIRCULATION OVER NORTH CENTRAL SOUTH DAKOTA...WITH A SHORTWAVE TROUGH/ASSOCIATED SURFACE COLD FRONT ENTERING NORTHWEST NORTH DAKOTA VIA THE NORTHERN BRANCH. LATEST RUC MAINTAINS A DRY FORECAST OVERNIGHT AND WILL CONTINUE WITH THAT IDEA...AS REGIONAL RADAR SHOWS THE NEAREST PRECIPITATION AREA IS IN FAR SOUTHEAST NORTH DAKOTA ASSOCIATED WITH THE UPPER LOW. THIS WILL ROTATE AROUND THE LOW AND APPROACH OUR SOUTHEAST BORDER BY AROUND 12Z WEDNESDAY. THE CURRENT FORECAST HAS A SLIGHT CHANCE BY THAT TIME AND NO ADJUSTMENTS NEEDED. THE COLD FRONT WILL PROGRESS SOUTH OVERNIGHT WITH WINDS SHIFTING TO THE NORTHEAST. SCT/BKN CLOUDS WILL ACCOMPANY THE FRONTAL PASSAGE BUT REMAINING DRY. UPDATE ISSUED AT 930 PM CDT TUE MAY 7 2013 FORECAST REMAINS VALID. CONVECTION CONTINUES TO DISSIPATE ACROSS FAR SOUTHEASTERN EMMONS AND FAR SOUTHWESTERN MCINTOSH COUNTIES WITH THE ONSET OF DARK. THIS AREA OF PRECIPITATION SHOULD BE GONE BY 04Z. FRONTAL PASSAGE WILL PUSH SOUTH OVERNIGHT INTO WEDNESDAY MORNING...WITH NORTHEAST WINDS INCREASING TO NEAR 20 MPH BEHIND THE FROPA AND CONTINUING THROUGH WEDNESDAY DAYTIME. WILL SEE ANOTHER ROUND OF DIURNAL SHOWERS/ISOLATED THUNDERSTORMS LATE WED MORNING AND AFTERNOON FAR SOUTH. UPDATE ISSUED AT 651 PM CDT TUE MAY 7 2013 THE INHERITED FORECAST IS MAINLY ON TRACK. ADJUSTED POPS ACCORDINGLY BASED ON LATEST REGIONAL RADAR. CONVECTION HAS JUST RECENTLY FIRED OFF OVER SOUTHERN EMMONS COUNTY WITH ONE CLOUD TO GROUND LIGHTNING STRIKE JUST SOUTH OF THE STATE LINE. STILL DO NOT ANTICIPATE ANY SEVERE WEATHER THIS EVENING WITH 0-6KM BULK WIND SHEAR LESS THAN 20KTS AND BOUNDARY LAYER MOISTURE VERY LIMITED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 335 PM CDT TUE MAY 7 2013 INSTABILITY WILL CONTINUE TO INCREASE ACROSS EXTREME SOUTH CENTRAL AND SOUTHEASTERN NORTH DAKOTA THIS AFTERNOON. AN AREA OF CONVECTION ASSOCIATED WITH A STAGNANT UPPER LOW HAS ALREADY DEVELOPED IN CENTRAL SOUTH DAKOTA THIS AFTERNOON. THIS ACTIVITY SHOULD SERVE AS A MOISTURE SOURCE FOR POSSIBLE AFTERNOON CONVECTION. THE FLY IN THE OINTMENT IS THAT SYNOPTIC SUBSIDENCE NORTH OF THE UPPER LOW (USING Q-VECTOR DIVERGE AS A PROXY) SHOULD KEEP ANY CONVECTIVE ACTIVITY SHALLOW. STILL THINK ENOUGH MOISTURE/INSTABILITY WILL DEVELOP LATER THIS AFTERNOON TO WARRANT AT LEAST A CHANCE FOR THUNDERSTORMS ACROSS MCINTOSH...LAMOURE...AND DICKEY COUNTIES. THIS ACTIVITY SHOULD STAY WELL BELOW SEVERE LIMITS. PRECIP CHANCES ARE EXPECTED TO DIMINISH QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME HEATING. NORTHERN STREAM ENERGY MOVING ACROSS HUDSON BAY WILL PUSH A COLD FRONT INTO NORTHERN NORTH DAKOTA AFTER MIDNIGHT. HOWEVER...DRY CONDITIONS ARE EXPECTED AREAWIDE AFTER MIDNIGHT SINCE MOISTURE CONVERGENCE ALONG THE BOUNDARY SHOULD BE WEAK. THE INCREASING WINDS BEHIND THE FRONT SHOULD KEEP OVERNIGHT LOWS ABOVE NORMAL NORTH (WILLISTON-MINOT). HOWEVER...FORECASTED A FEW DEGREES BELOW THE COOLEST MOS GUIDANCE FOR OVERNIGHT LOWS SOUTH AS WINDS SHOULD REMAIN CALM SOUTH OF HIGHWAY 200 THROUGH SUNRISE. THE COLD FRONT WILL THEN PUSH THROUGH THE REMAINDER OF WESTERN AND CENTRAL NORTH DAKOTA WEDNESDAY. LINGERING MOISTURE AND INSTABILITY SHOULD BE ENOUGH TO WARRANT A CHANCE FOR THUNDERSTORMS OVER EXTREME SOUTH CENTRAL AND SOUTHEASTERN NORTH DAKOTA LATE WEDNESDAY MORNING AND EARLY AFTERNOON. GIVEN THE CURRENT PROGS OF THE SPEED OF THE FRONT...THE ATMOSPHERE SHOULD STABILIZE QUICKLY IN THE WAKE OF THE BOUNDARY SOUTH AND SOUTHEAST LATE WEDNESDAY AFTERNOON. WEDNESDAY HIGH TEMPERATURES SHOULD BE NEAR NORMAL...WITH READINGS FROM THE 60S SOUTH TO THE UPPER 50S NORTH. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 335 PM CDT TUE MAY 7 2013 THE MAIN FOCUS FOR THE LONG TERM IS A POTENTIALLY STRONG COLD FRONT BLASTING THROUGH THE REGION FRIDAY. THE STAGNANT SPLIT FLOW AND DOMINANT RIDGE TO THE WEST WILL BEGIN TO BREAK DOWN LATE THIS WEEK. THE STATIONARY UPPER LEVEL LOW IN SOUTH DAKOTA WILL EJECT EASTWARD MAKING WAY FOR THE APPROACHING LONG WAVE TROUGH AND ASSOCIATED COLD FRONT FRIDAY. A WEAK FRONT WILL SWING THROUGH THE NORTHERN PLAINS WEDNESDAY THROUGH THURSDAY. COLD DRY AIR ADVECTION BEHIND THE FRONT WILL CONTINUE THROUGH EARLY FRIDAY. THIS SHOULD LIMIT THE AMOUNT OF MOISTURE AND INSTABILITY AVAILABLE FOR THE FRIDAY SYSTEM. DUE TO THE PROGRESSIVE NATURE OF THE SYSTEM AND LACK OF MOISTURE AVAILABLE...PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT. BOTH THE GFS AND EURO SHOW STEEP LAPSE RATES...STRONG 0-6KM SHEAR OF 45-55 KNOTS AND MODERATE FRONTOGENESIS. THIS WOULD NORMALLY FAVOR STRONG THUNDERSTORMS. HOWEVER...DUE TO THE ABOVE MENTIONED LACK OF MOISTURE ...ONLY SHOWERS WITH ISOLATED THUNDERSTORMS ARE EXPECTED. THE 00Z EURO AND 12Z GFS SHOW SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THE FRONT FRIDAY AFTERNOON AND QUICKLY EXITING NORTH DAKOTA BY LATE FRIDAY EVENING. NORTHERLY WINDS WILL USHER IN COLD AIR SATURDAY. DROPPING TEMPERATURES SATURDAY 10 TO 15 DEGREES BELOW NORMAL. SUNDAY AND MONDAY A HIGH AMPLITUDE RIDGE WILL PARK OVER EASTERN MONTANA AND WESTERN NORTH DAKOTA. THIS RIDGE COMBINED WITH STRONG WARM AIR ADVECTION WILL ALLOW TEMPERATURES TO RISE 10 TO 20 DEGREES ABOVE NORMAL WITH READINGS IN THE 80S BY MONDAY OVER SOUTHWEST NORTH DAKOTA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1237 AM CDT WED MAY 8 2013 LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW VFR CIGS/ VSBYS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. SCT/BKN MID CLOUDS AT KJMS ASSOCIATED WITH AN UPPER LEVEL LOW IN SOUTH DAKOTA...AND CLOUDS INCREASING ALONG THE NORTHERN BORDER BEHIND AN ADVANCING COLD FRONT. THIS COLD FRONT WILL MOVE THROUGH THE AERODROMES THROUGH 15Z WEDNESDAY WITH A WIND SHIFT TO THE NORTHEAST. EXPECT WINDS WEDNESDAY TO RANGE BETWEEN 15KT AND 20KT. EXPECTING DRY CONDITIONS WITH THIS FRONT AT LEAST THROUGH 06Z THURSDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...TM LONG TERM...AJ AVIATION...KS
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
412 AM CDT WED MAY 8 2013 .DISCUSSION... AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR THIS ACTIVITY. LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z. MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN THREAT WITH THUNDERSTORMS THROUGH THIS EVENING. THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA. THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON. HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF THE AREA. BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT WEEK. TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS THROUGH THE NEXT 7 DAYS. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20 WACO, TX 86 63 83 64 83 / 10 10 50 70 30 PARIS, TX 85 59 79 62 79 / 5 10 30 50 20 DENTON, TX 85 63 83 62 80 / 10 10 40 60 20 MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20 DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20 TERRELL, TX 85 62 81 63 82 / 5 10 40 60 30 CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30 TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30 MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
721 AM EDT WED MAY 8 2013 .SYNOPSIS... A BROAD AREA OF LOW PRESSURE CENTERED OVER VIRGINIA EARLY TODAY WILL DRIFT TO THE NORTHEAST AND PASS SLOWLY OVER OUR REGION THROUGH THURSDAY. A WARM FRONT AND NEW AREA OF LOW PRESSURE MAY ORGANIZE NEAR THE MID ATLANTIC STATES FRIDAY NIGHT INTO SATURDAY. A COLD FRONT IS FORECAST TO FOLLOW EARLY ON SUNDAY WITH HIGH PRESSURE BUILDING TO OUR SOUTH ON MONDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE DEEP BUT ATLANTIC MOISTURE PLUME MOVING AROUND THE SLOWLY ADVANCING AND STACKED LOW AND SOME ELEVATED INSTABILITY WERE CAUSING A SWATH OF RAIN WITH SOME EMBEDDED THUNDER FROM WELL OFF THE SOUTHERN DELMARVA INTO NORTHEAST NEW JERSEY EARLY THIS MORNING. ACTIVITY QUICKLY BECAME MORE SCATTERED AS ONE MOVED SOUTHWEST. AS OF 09Z, THE MESOSCALE NAM AND THE HRRR HAD SHIFTED THE AXIS OF BEST RAINFALL FURTHER NORTH, BUT UNFORTUNATELY RADAR RETURNS SHOWED THE SWATH DEVELOPING A WESTWARD MOVEMENT. WE HAVE MENTIONED THE POSSIBILITY OF HEAVY RAIN THIS MORNING FROM EAST CENTRAL THROUGH NORTH CENTRAL NEW JERSEY AND INTO THE SOUTHERN POCONOS. ALL MODELS STILL SHIFT THE RAIN NORTH WITH TIME TODAY. OUR FORECAST STILL LIFTS THE PRECIPITATION NORTH AND OUT OF THE AREA THIS MORNING AND THEN RE-FOCUSES ON THE LOW. SOME ENERGY IS FORECAST TO REVOLVE AROUND THE LOW, AND IT ESPECIALLY SEEMS TO TARGET OUR WESTERN ZONES. WE CARRY A SLIGHT CHANCE OF THUNDER FIRST WITH THE SWATH OFF THE OCEAN. WE THEN EXTEND THE SLIGHT CHANCE AROUND THE FORECAST AREA AS THE LOW APPROACHES AND TEMPERATURES COOL ALOFT. MID LEVEL CLOUDS HAD BROKEN FAR SOUTH, AND THIS HAD ALLOWED SOME FOG TO FORM THERE. THAT IS COVERED IN THE FORECAST AND WITH A SPECIAL WEATHER STATEMENT THAT RUNS UNTIL 1330Z. TEMPERATURES ARE ON THE COOLER SIDE OF GUIDANCE, ALTHOUGH WE DO START FROM A FAIRLY WARM PLACE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... THE MODELS SHOW DECENT AGREEMENT REGARDING MORE ENERGY ROTATING AROUND THE LOW AND LIFTING FROM THE SOUTH INTO OUR FORECAST AREA TONIGHT, AND WE CARRY HIGH CHANCE POPS IN RESPONSE. AGAIN, WE ARE NOT MENTIONING ANY HEAVY RAIN. WE DO CARRY THUNDER THROUGH THE EVENING. TEMPERATURES ARE A GUIDANCE/CONTINUITY BLEND. && .LONG TERM /THURSDAY THROUGH TUESDAY/... UNSETTLED CONDITIONS WILL REMAIN ACROSS THE AREA FROM THURSDAY INTO THE WEEKEND. FIRST...THE WEAKENING UPPER LOW WILL CONTINUE TO TRANSLATE NORTHEAST ACROSS THE REGION. WHILE THE SYSTEM IS NOT VERY STRONG...IT WILL HAVE ENOUGH ENERGY/INSTABILITY TO CREATE SOME SCT SHOWERS INTO THE FIRST PART OF THE EXTENDED. A BRIEF BREAK BEHIND THE LOW MAY CREATE LESSER CHC FOR PCPN FRIDAY...THEN ANOTHER SYSTEM APPROACHED FROM THE OHIO VALLEY FRI NIGHT AND LINGERS ACROSS THE AREA INTO SUNDAY. THE APPROACHING SYSTEM LATER FRI MAY ARRIVE EARLY ENOUGH TO PRODUCE SOME SVR TSTMS ACROSS THE NW ZONES. THE SPC HAS PLACED A SLGT RISK FOR SVR TSTMS THAT DAY. A COLD FRONT WILL BRING DRIER AIR AND COOLER TEMPERATURES LATER SUNDAY. THESE COOLER READINGS WILL LAST INTO EARLY NEXT WEEK. EXCEPT FOR FRIDAY...TEMPERATURES WILL MOSTLY BE NORMAL OR BELOW NORMAL ACROSS THE REGION. ON FRIDAY...DAYTIME HEATING SHOULD BOOST READINGS WELL INTO THE 70S AND LOW 80S ACROSS THE AREA. IT WILL REMAIN COOLER ALONG THE SHORE ON FRIDAY. && .AVIATION /11Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. WITH THE 12Z TAFS WE ARE STARTING THEM FAIRLY PESSIMISTICALLY WITH IFR CONDITIONS AS LOW CLOUDS HAVE DEVELOPED AND NUMEROUS SHRAS ARE AROUND. THUNDER PRECLUDED BECAUSE OF THEIR CURRENT LOCATIONS (NE OF TERMINALS) AND MOTION. THE PRESENT TAFS WILL STAY OPTIMISTIC IN LIFTING THE IFR STRATUS EARLIER THAN WE HAD BEEN FORECASTING. ALL SITES BREAK OUT TO VFR BY 16Z IN THE PRESENT TAFS, WITH THE SOUTHEASTERN AND DELAWARE VALLEY SITES BREAKING OUT DURING THE DAYLIGHT MORNING HOURS. WE WILL MONITOR. WE HAVE CONTINUED THE OPTIMISTIC FORECAST INTO THE AFTERNOON BY ONLY FORECASTING A PROB30 FOR TSTM ACTIVITY AT MOST SITES (NOT THE SOUTHEASTERN ONES) AND THEN GOING VFR THROUGH 09/06Z (12Z AT PHL). WE MAY ULTIMATELY INSERT AT LEAST SOME STRATUS INTO THE FORECAST FOR THE PERIOD AFTER 06Z IN SUBSEQUENT ISSUANCES. WINDS ARE NOT EXPECTED TO BE A MAIN CONCERN TODAY, BUT THEY SHOULD VEER FROM EAST OR NORTHEAST TO SOUTHEAST DURING THE TAF PERIOD AT 10 KT OR LESS. OUTLOOK... THU INTO FRI NIGHT...MOSTLY VFR. SCATTERED SHOWERS/TSTMS FRI AFTERNOON MAY BRING LOWER CIGS/VSBYS. SAT THRU SUN...LOWER CONDITIONS EXPECTED WITH CIGS/SHOWERS SAT AND SAT NIGHT. IMPROVING CONDITIONS LATER SUNDAY. && .MARINE... WITH BROAD LOW PRESSURE APPROACHING OUR REGION AND A CONTINUED ONSHORE FLOW, SEAS ARE EXPECTED TO BE ELEVATED THROUGH TONIGHT ON OUR ATLANTIC COASTAL WATERS. A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CONTINUES FOR ALL OF OUR ATLANTIC COASTAL WATERS THROUGH TONIGHT. SEAS AND WINDS ARE EXPECTED TO REMAIN BELOW SCA LEVELS FOR DELAWARE BAY. VISIBILITIES WILL BE LOWERED AT TIMES IN SCATTERED SHOWERS AND ISOLATED THUNDER MAINLY THIS AFTERNOON, ALTHOUGH NORTHERN ATLANTIC WATERS WILL SEE SOME HEAVIER RAIN AND PERHAPS SOME THUNDER EARLY THIS MORNING. ANOTHER SHOT OF SHOWER AND THUNDERSTORM ACTIVITY IS POSSIBLE TONIGHT. OUTLOOK...SCA CONDITIONS FOR HAZ SEAS WILL PROBABLY COME DOWN THU MORNING AS THE LONGER PERIOD SWELLS DIMINISH. ANOTHER PERIOD OF SCA CONDITIONS WILL DEVELOP ACROSS THE OCEAN WATERS FRI NIGHT AND LAST INTO THE WEEKEND. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT THURSDAY FOR ANZ450>455. && $$ SYNOPSIS...GIGI/O`HARA NEAR TERM...DELISI SHORT TERM...DELISI LONG TERM...O`HARA AVIATION...DELISI/GIGI MARINE...DELISI
AREA FORECAST DISCUSSION
NWS MIAMI FL
1052 AM EDT WED MAY 8 2013 .UPDATE...NO CHANGES ARE NEEDED TO THE FORECAST THIS MORNING. THE MIAMI SOUNDING SHOWS VERY DRY AIR PRESENT WITH A PWAT OF ONLY 0.70 INCHES. MEAN WESTERLY STEERING FLOW CONTINUES, AND BOTH TPA AND KEY SHOW SLIGHTLY HIGHER MOISTURE IN THE LOWER LEVELS. COULD THIS BE JUST ENOUGH ADVECTING IN THIS AFTERNOON TO PRODUCE A FEW SHOWERS? ALL GUIDANCE SAYS NO, EXCEPT HRRR SHOWS A SMALL LIGHT SHOWER EARLY THIS EVENING OVER INTERIOR PALM BEACH, BUT THAT`S IT. GIVEN THIS, HAVE OPTED TO KEEP SHOWER MENTION OUT OF THE FORECAST AS MOST, AND LIKELY ALL, AREAS WILL REMAIN DRY TODAY. PLEASANT LOW HUMIDITY CONTINUES WITH DEWPOINTS IN THE 50S! /GREGORIA && .PREV DISCUSSION... /ISSUED 730 AM EDT WED MAY 8 2013/ AVIATION... VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD. WINDS WILL REMAIN VARIABLE ACROSS ALL OF THE SOUTH FLORIDA TERMINALS THROUGH THE MIDDLE OF WEDNESDAY MORNING. AN EAST COAST SEA BREEZE WILL DEVELOP AROUND 19-21Z WEDNESDAY BEFORE DIMINISHING WEDNESDAY EVENING. AT KAPF, WINDS WILL SHIFT TO THE SOUTHWEST AS A WEST COAST SEA BREEZE DEVELOPS WEDNESDAY AFTERNOON. && .PREV DISCUSSION... /ISSUED 322 AM EDT WED MAY 8 2013/ .DISCUSSION... ANOTHER QUIET...COOL AND DRY EARLY MAY MORNING FOR SOUTH FLORIDA. AN UPPER LEVEL LOW ACROSS NORTH CAROLINA AND VIRGINIA WILL FINALLY BEGIN TO MOVE NORTHEAST. SO THE UPPER TROUGH OVER THE REGION WILL GET REPLACED WITH A MORE ZONAL PATTERN BY THE WEEKEND. SURFACE HIGH PRESSURE OVER THE REGION WILL ALLOW FOR LIGHT WINDS...SUNNY SKIES...AND WARM AFTERNOON TEMPERATURES. THE SUBTROPICAL RIDGE...WHICH WAS LOCATED OVER THE BAHAMAS AND CUBA...WILL SLOWLY MOVE NORTH TO THE FLORIDA KEYS ON THURSDAY AS THE UPPER LEVEL LOW MOVES INTO THE NORTHEAST. THIS WILL ALSO BRING A SMALL INCREASE TO THE LOW LEVEL MOISTURE TO THE REGION. MODELS ARE INDICATING THAT THE SUBTROPICAL JET WILL MOVE BACK NORTH TOWARDS SOUTH FLORIDA ONCE AGAIN...AND A WEAK SHORTWAVE MAY MOVE ACROSS THE REGION THURSDAY AFTERNOON. DRY AIR WILL STILL REMAIN IN THE LOW/MID LEVELS...SO NO MORE THAN AN ISOLATED SHOWER OR TWO IS EXPECTED. KEPT A SILENT 10 POP IN PLACE FOR NOW. THE SURFACE RIDGE AXIS WILL MOVE NORTH OF THE REGION THURSDAY NIGHT...WITH EASTERLY FLOW RETURNING TO SOUTH FLORIDA. SO THIS WILL END THE COOLER THAN NORMAL OVERNIGHT TEMPERATURES. LOW PRESSURE IS FORECAST TO DEVELOP ACROSS THE OHIO VALLEY AND MOVE INTO THE NORTHEAST ON FRIDAY...AND A CLIPPER SYSTEM WILL MOVE ACROSS THE NORTHERN TIP OF LAKE SUPERIOR ON SATURDAY. A FEW SHOWERS OR STRAY THUNDERSTORM COULD DEVELOP ALONG THE INTERIOR FRIDAY AND SATURDAY ALONG THE SEA BREEZE BOUNDARIES. A BROAD UPPER TROUGH WILL THEN DEVELOP ACROSS THE GREAT LAKES AND INTO THE SOUTHEAST ON SUNDAY. A COLD FRONT IS EXPECTED TO PUSH INTO THE SOUTHEAST AND NORTHERN FLORIDA ON SUNDAY...AND AN AREA OF LOW PRESSURE MAY ALSO DEVELOP AND MOVE NORTHEAST ALONG THE BOUNDARY. LOW LEVEL FLOW WILL SHIFT MORE TO THE SOUTH...AND LOW LEVEL MOISTURE WILL INCREASE ACROSS THE REGION. SO RAIN CHANCES WILL BEGIN TO INCREASE ON SUNDAY FOR THE AREA. HOWEVER...THE GREATEST CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD WILL BE ON MONDAY AS THE FRONTAL BOUNDARY MOVES INTO THE REGION. THE FRONT IS EXPECTED TO MOVE THROUGH THE REGION MONDAY NIGHT INTO TUESDAY MORNING...WITH DRIER AIR PUSHING INTO SOUTH FLORIDA. HOWEVER...SHALLOW MOIST NORTHEASTERLY FLOW AROUND SURFACE HIGH PRESSURE MAY ALLOW FOR A FEW SHOWERS TO PUSH ACROSS THE ATLANTIC AND INTO SOUTH FLORIDA. TEMPERATURES WILL SLOWLY RISE THROUGH THE WEEKEND AS HEIGHTS SLOWLY RISE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 83 66 85 72 / 0 0 10 10 FORT LAUDERDALE 84 68 85 74 / 0 0 10 10 MIAMI 86 67 87 74 / 0 0 10 10 NAPLES 79 63 83 68 / 0 0 - 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1056 AM CDT WED MAY 8 2013 ...UPDATED FORECAST FOR THUNDERSTORM POTENTIAL THROUGH TONIGHT... .UPDATE... ISSUED AT 1042 AM CDT WED MAY 8 2013 THE FORECAST REMAINS A BIT TRICKY REGARDING MESOSCALE FEATURES AS WEAKENING AREA OF PRECIP AND ASSOCIATED WEAK MCV OVER SOUTHEAST KANSAS HAS INTERFERED WITH THE BROAD SCALE SURFACE PATTERN. SURFACE LOW PRESSURE REMAINS CENTERED OVER THE OKLAHOMA PANHANDLE WITH SOME SEMBLANCE OF A SURFACE TROUGH EXTENDING NORTHEAST THROUGH CENTRAL KANSAS AND INTO EXTREME NORTHEAST KANSAS. THESE FEATURES ARE NOT EXPECTED TO MOVE MUCH THROUGH THE DAY TODAY. SOUTHERLY FLOW HAS RESUMED INTO CENTRAL KANSAS IN THE WAKE OF THE PRECIPITATION BUT SOUTHEASTERLY LOW LEVEL FLOW PERSISTS OVER SOUTHEAST KANSAS BEHIND A WEAK OUTFLOW BOUNDARY OF SORTS. THIS COLD POOL AIRMASS IS EXPECTED TO MIX OUT WITH SOUTHERLY FLOW RESUMING BY EARLY AFTERNOON BUT WEAK REMNANT BOUNDARIES MAY PROVIDE JUST ENOUGH FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT BY MID TO LATE AFTERNOON. DRIER MID LEVEL AIR WITH STEEPENING LAPSE RATES IS ALSO FORECAST TO MOVE NORTHEAST INTO THE FORECAST AREA BY THIS AFTERNOON AND SHOULD CONTRIBUTE TO SURFACE BASED INSTABILITY TO AROUND 2000 J/KG WITH MINIMAL INHIBITION. WEAK CONVERGENCE ALONG THE SURFACE TROUGH AXIS AND ANY WEAK REMNANT BOUNDARIES WILL LIKELY BE SUFFICIENT TO OVERCOME THE WEAK INHIBITION LATE THIS AFTERNOON AND THIS EVENING BUT THE EXTENT OF THUNDERSTORM COVERAGE REMAINS IN QUESTION THROUGH THIS PERIOD. DEEP LAYER SHEAR PROFILES ARE EXPECTED TO BE RATHER WEAK...PERHAPS SUPPORTING BRIEF SUPERCELL STRUCTURES BUT MORE LIKELY IN THE MULTICELL REALM OF CONVECTION. AT THIS TIME...IT APPEARS THAT THE STRONGEST STORMS MAY BE CAPABLE OF PRODUCING ISOLATED AND MARGINALLY SEVERE HAIL AND DOWNBURST WINDS. LATE THIS EVENING AND OVERNIGHT...IT APPEARS THAT CONVECTION OVER THE HIGH PLAINS WILL MERGE INTO AN MCS OF SORTS WHICH SHOULD RIDE ALONG THE SURFACE TROUGH AXIS AND NORTH EDGE OF THE INSTABILITY AXIS ACROSS KANSAS...WITH INCREASING CHANCES FOR THUNDERSTORMS AFTER MIDNIGHT. STRONG WINDS ARE NOT OUT OF THE QUESTION WITH THIS ACTIVITY...BUT FEEL THAT THE INSTABILITY WILL BE WANING BY THE TIME STORMS REACH EASTERN KANSAS AND MAY NO LONGER SUPPORT A SEVERE WEATHER THREAT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM CDT WED MAY 8 2013 08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB. FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS. LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND POSSIBLY SOME DAMAGING WIND GUSTS. WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3 AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH. SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON THE WARM SIDE OF THE TROUGH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 356 AM CDT WED MAY 8 2013 ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY. A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN THE LOW TO MIDDLE 80S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 635 AM CDT WED MAY 8 2013 TIMING TS WILL BE THE MAIN DIFFICULTY IN THE FORECAST. WITH MODELS SHOWING LITTLE OR NO INHIBITION DURING PEAK HEATING AND THE SFC TROUGH AXIS PROGGED TO BE IN THE VICINITY OF THE TERMINALS...THINK THUNDERSTORMS WILL BE MOVING THROUGH THE TERMINALS BY THE EARLY EVENING. HAVE KEPT TAFS VFR FOR NOW WITH MODELS SHOWING CIGS ABOVE 3 KFT THROUGH THE DAY...UNTIL TS TIMING BECOMES MORE APPARENT. THE MAIN RESTRICTION WOULD LIKELY BE REDUCED VSBY FROM MODERATE OR HEAVY RAINFALL. THERE IS SOME INDICATION OF LOWER CIGS FINALLY MOVING IN AS THE SURFACE TROUGH AXIS MOVES SOUTH. HOWEVER THIS LOOKS TO BE AROUND THE END OF THE FORECAST PERIOD...SO WILL LET LATER SHIFTS DIAGNOSE THIS MORE. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARJENBRUCH SHORT TERM...WOLTERS LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
635 AM CDT WED MAY 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM CDT WED MAY 8 2013 08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB. FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS. LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND POSSIBLY SOME DAMAGING WIND GUSTS. WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3 AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH. SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON THE WARM SIDE OF THE TROUGH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 356 AM CDT WED MAY 8 2013 ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY. A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN THE LOW TO MIDDLE 80S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 635 AM CDT WED MAY 8 2013 TIMING TS WILL BE THE MAIN DIFFICULTY IN THE FORECAST. WITH MODELS SHOWING LITTLE OR NO INHIBITION DURING PEAK HEATING AND THE SFC TROUGH AXIS PROGGED TO BE IN THE VICINITY OF THE TERMINALS...THINK THUNDERSTORMS WILL BE MOVING THROUGH THE TERMINALS BY THE EARLY EVENING. HAVE KEPT TAFS VFR FOR NOW WITH MODELS SHOWING CIGS ABOVE 3 KFT THROUGH THE DAY...UNTIL TS TIMING BECOMES MORE APPARENT. THE MAIN RESTRICTION WOULD LIKELY BE REDUCED VSBY FROM MODERATE OR HEAVY RAINFALL. THERE IS SOME INDICATION OF LOWER CIGS FINALLY MOVING IN AS THE SURFACE TROUGH AXIS MOVES SOUTH. HOWEVER THIS LOOKS TO BE AROUND THE END OF THE FORECAST PERIOD...SO WILL LET LATER SHIFTS DIAGNOSE THIS MORE. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...WOLTERS LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS GRAY ME
645 AM EDT WED MAY 8 2013 .SYNOPSIS... LOW PRESSURE WHICH HAS BEEN STALLED OVER THE SOUTH FOR THE LAST WEEK WILL WEAKEN AND LIFT NORTH INTO OUR AREA TODAY INTO THURSDAY. A STRONGER LOW MAY MOVE THROUGH LATER IN THE WEEKEND. A FRONT WILL STALL OVER THE REGION THIS WEEKEND...WITH WAVES OF LOW PRESSURE TRAVELING ALONG IT. && .NEAR TERM /THROUGH TONIGHT/... LOW CLOUDS AND FOG ENTERING THE REGION FROM THE GULF OF MAINE WILL BURN OFF THIS MORNING AND IS NOW IN SOUTHERN INTERIOR MAINE. THIS MOISTURE MAY TAKE AN HOUR OR TWO LONGER THAN YESTERDAY TO MIX OUT. MEANWHILE...CLOUDS WILL BEGIN TO INCREASE FROM SOUTH TO NORTH TODAY AHEAD OF SLOW MOVING...AND WEAKENING CUTOFF LOW PRESSURE SYSTEM. ENOUGH SUPPORT TO ADD LOW CHC POPS TO THE FCST FOR THE AFTERNOON HOURS. LATEST HRRR RUN BRINGS A BAND OF SHOWERS INTO SW NH AROUND 19 OR 20Z. MAX TEMPS WILL ONCE AGAIN APPROACH 80 DEGRESS WELL IN TO THE INTERIOR TODAY...WITH MAINLY 60S ALONG THE COAST. USED A BLEND OF MAV/MET MOS NOS FOR AFTERNOON HIGHS. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AREAS OF FOG WILL REDEVELOP ONCE AGAIN TONIGHT. SOUTHERLY FLOW OFF THE BRINK AS WELL AS THE APPROACH OF THE UPPER LEVEL TROUGH WILL ALLOW FOR SCT SHOWER ACTIVITY OVER ALL PTNS OF ME/NH. PATCHY DRIZZLE WILL BE PSBL ALG AND NEAR THE COASTLINE AS WELL. THE PATTERN WILL REMAIN UNSETTLED ON THURSDAY AS THE UPPER TROUGH SLOWLY ENTERS THE REGION. HIGHEST POS WILL BE IN THE MTNS OF MAINE. && .LONG TERM /FRIDAY THROUGH TUESDAY/... A SLOW MOVING FRONT WILL REMAIN BANKED UP TO OUR NORTHWEST THURSDAY NIGHT. ALL MODELS CONTINUE TO SHOW A WEAK WAVE TRAVELING ALONG THIS FEATURE...TRIGGERING MORE SCT SHOWERS ACROSS THE REGION. THE FRONT BECOMES NEARLY STATIONARY OVER THE WEEKEND...WITH DRIER AIR NOT ADVECTING INTO THE REGION UNTIL SUNDAY. THE FRONT WILL MOVE OFF THE COAST BY MONDAY...ALLOWING MUCH DRIER AND COOLER AIR TO FINALLY ENTER THE REGION. GUSTY WINDS WILL ACCOMPANY THE COLD AIR ADVECTION ON MONDAY. ANOTHER WEATHER DISTURBANCE WILL BRING THE THREAT OF SHOWERS DURING THE MIDWEEK PERIOD. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM... CONDITIONS ARE EXPECTED TO BE IFR WITH LOCALLY LIFR IN FOG AND LOW CLOUDS ALONG COASTAL AREAS AND JUST INLAND FROM THE COAST EARLY THIS MORNING. THE FOG WILL BE MORE WIDESPREAD TONIGHT INTO THURSDAY. LONG TERM...MVFR CONDITIONS ARE EXPECTED AT TAF SITES AS AN UPPER LOW BRINGS SHOWERS TO THE REGION. SHOWERS WILL REDEVELOP ON FRIDAY AHEAD OF A STRONG COLD FRONT. INSTABILITY SHOWERS WILL PERSIST INTO THIS WEEKEND BEHIND THE COLD FRONT. && .MARINE... SHORT TERM...WINDS AND SEAS WILL BE BELOW SCA. PATCHY FOG IS EXPECTED ACROSS THE WATERS TODAY WITH AREAS OF FOG TONIGHT INTO THURSDAY. LONG TERM... WIND GUSTS WILL INCREASE FRIDAY AFTERNOON AS A COLD FRONT APPROACHES NORTHERN NEW ENGLAND. NO HEADLINES ARE EXPECTED. WINDS MAY BECOME GUSTY BEHIND A COLD FRONT EARLY NEXT WEEK. && .FIRE WEATHER... MORE HUMID AIR WILL CONTINUE TO FILTER INTO SOUTHERN AREAS TODAY. HOWEVER...NORTHERN AREAS WILL CONTINUE TO BE DRY. CLOUDS WILL INCREASE AND THICKEN LATER TODAY...ALLOWING SCATTERED SHOWERS TO ENTER THE REGION. SCATTERED SHOWERS WILL CONTINUE RIGHT THROUGH THE WEEKEND...WITH MORE WIDESPREAD SHOWER ACTIVITY POSSIBLE FRIDAY NIGHT. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
616 AM CDT WED MAY 8 2013 .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 329 AM CDT WED MAY 8 2013 LITTLE CHANGE IN THINKING THIS MORNING SINCE PREVIOUS FORECAST. THE PRIMARY CHALLENGE THIS MORNING IS TIMING THE START OF PRECIP TODAY. IF CURRENT RADAR TRENDS HOLD TRUE...THE SHOWERS CURRENTLY OVER KANSAS WILL REACH THE WESTERN-MOST PORTIONS OF OUR CWFA BETWEEN 16-17Z. THIS TIMING AGREES WELL WITH MOST SHORT RANGE MODEL GUIDANCE INCLUDING THE HRRR AND 4KM NCEP WRF. SHOULD SEE INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTHEAST MISSOURI TONIGHT AS THE COMPACT SHORTWAVE OVER SOUTH DAKOTA DRIFTS SOUTHEAST INTO IOWA. THIS FORCES THE LOW LEVEL JET TO STRENGTHEN OVER THE AREA CAUSING AMPLE LOW LEVEL MOISTURE CONVERGENCE OVER REGION WHICH SHOULD KEEP PRECIPITATION GOING OVER CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS FOR MUCH OF THE NIGHT. THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ACROSS THE REST OF THE AREA ON THURSDAY AS DAYTIME HEATING DESTABILIZES THE ATMOSPHERE AND THE SHORTWAVE CONTINUES TO DIG INTO THE MID-MISSISSIPPI VALLEY. STRONG STORMS ARE POSSIBLE...THO CONDITIONS APPEAR MARGINAL FOR SEVERE WITH 1000-1200 J/KG CAPE BUT ONLY 15-20KTS OF SHEAR. IF THERE ARE SEVERE STORMS WOULD THINK THE PRIMARY THREAT WILL BE DAMAGING WINDS...HAIL THREAT SEEMS LIMITED DUE TO SMALL CAPE VALUES IN THE HAIL GROWTH ZONE. SHOULD SEE PRECIP DECREASE FROM NORTHWEST TO SOUTHEAST LATE THURSDAY NIGHT INTO THE PRE-DAWN HOURS OF FRIDAY MORNING. CANNOT RULE OUT SCATTERED SHOWERS AND THUNDERSTORMS GENERALLY ALONG AND SOUTH OF I-70 AGAIN FRIDAY...BUT THINK THE THREAT FOR ORGANIZED CONVECTION WILL BE MINIMAL. TEMPERATURE TRENDS THROUGH FRIDAY WILL BE HIGHLY DEPENDENT ON PRECIPITATION. GENERALLY STUCK PRETTY CLOSE TO THE MIDDLE OF THE ROAD OF GUIDANCE NUMBERS. CARNEY .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 329 AM CDT WED MAY 8 2013 GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH THE SATURDAY THROUGH MONDAY PERIOD. ANOTHER SHORTWAVE WILL DIG SOUTHEAST OUT OF CANADA INTO THE GREAT LAKES REGION AMPLIFYING THE FLOW ACROSS THE U.S. THIS WILL PUSH A COLD FRONT SOUTH THROUGH THE MISSISSIPPI VALLEY ON SATURDAY. A STRONG CANADIAN HIGH WILL DROP INTO THE ARE BEHIND THE FRONT BRINGING US ANOTHER SHOT OF BELOW NORMAL TEMPERATURES. GFS AND ECMWF CONTINUE TO PRODUCE VERY LIGHT QPF ACROSS PARTS OF THE AREA ON SATURDAY AS THE FRONT MOVES THROUGH SO HAVE KEPT CHANCE POPS IN THE FORECAST. 850MB TEMPS DROP TO NEAR ZERO SUNDAY SO HAVE CONTINUED THE DOWNWARD TREND FOR HIGHS...UNDERCUTTING GUIDANCE BY A FEW DEGREES. MONDAY MORNING WILL LIKELY BE THE COLDEST OF THE BUNCH...WITH POSSIBLY THE LAST FROST OF THE SEASON. SHOULD SEE A NICE WARM UP MONDAY AFTERNOON AND TUESDAY AS AN UPPER LEVEL RIDGE BUILDS OVERHEAD AND SOUTHWEST FLOW RETURNS TO THE AREA. CARNEY && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 604 AM CDT WED MAY 8 2013 OTHER THAN SOME LOW LYING FOG AT KSUS AND KCPS THIS MORNING CONDITIONS REMAINED VFR OVERNIGHT. AREA OF RAIN AND THUNDERSTORMS OVER KANSAS WILL WEAKEN SIGNIFICANTLY AS IT MOVES EAST...WITH PERHAPS A SHOWER OR SPRINKLE AFFECTING THE TERMINALS THIS AFTERNOON. OTHERWISE...THE BETTER CHANCE OF RAIN AND THUNDERSTORMS WILL WAIT UNTIL OVERNIGHT ACROSS NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS AND THURSDAY MORNING AT THE REMAINING TERMINALS. LIGHT WIND WILL BECOME SOUTHERLY TODAY...AND THEN BACK TO THE EAST-SOUTHEAST FROM OUTFLOW OF CONVECTION EITHER OVERNIGHT OR THURSDAY MORNING. SPECIFICS FOR KSTL... INCREASING HIGH CLOUD COVER TODAY WITH A WEAKENING LINE OF SHOWERS EXPECTED TO MOVE ACROSS THE TERMINAL LATE THIS AFTERNOON. BETTER CHANCE OF RAIN HOLDS OFF UNTIL EITHER LATE TONIGHT OR THURSDAY. LIGHT WIND TO BECOME SOUTHERLY. CVKING && .PRELIMINARY POINT TEMPS/POPS... SAINT LOUIS 83 62 78 60 / 10 40 60 60 QUINCY 78 59 73 54 / 40 80 80 60 COLUMBIA 78 59 74 57 / 40 80 70 60 JEFFERSON CITY 79 60 75 58 / 40 70 60 60 SALEM 79 58 78 61 / 10 10 60 60 FARMINGTON 79 59 77 59 / 20 20 50 60 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
744 AM EDT WED MAY 8 2013 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL BRING INCREASING CLOUDS ALONG WITH A CHANCE OF SHOWERS AND COOLER TEMPERATURES TO THE REGION BY LATER TODAY INTO THURSDAY. A COLD FRONT WILL SWING INTO THE AREA BY FRIDAY INTO SATURDAY WITH A WIDESPREAD AND WELCOMED RAINFALL LIKELY. COOL AND MAINLY DRY WEATHER WILL RETURN BY SUNDAY INTO MONDAY OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 630 AM EDT WEDNESDAY...MODEST UPDATES TO DEWPOINTS THROUGH TODAY PER LATEST OBS AND RUC13 DATA. ALSO TWEAKED HOURLY TEMPERATURES OVER THE NEXT FEW HOURS TO ACCOUNT FOR CURRENT OBSERVATIONAL TRENDS. NO APPRECIABLE CHANGES TO WORDED FORECAST HOWEVER. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS... HIGH PRESSURE WHICH BROUGHT WARM AND DRY WEATHER TO THE REGION FOR OVER A WEEK WILL FINALLY SLIDE EAST AND ALLOW UPPER LEVEL LOW PRESSURE TO PUSH NORTHWARD FROM THE MID ATLANTIC STATES. THUS CLEAR/SUNNY SKIES THIS MORNING WILL GRADUALLY GIVE WAY TO THICKENING CLOUD COVER FROM THE SOUTH THROUGH THE MORNING AND AFTERNOON HOURS AS DEEPER MOISTURE SLOWLY PINWHEELS NORTH. HOWEVER DRY LOWER LEVELS WILL KEEP MOST PRECIPITATION CONFINED TO OUR CENTRAL AND SOUTHERN COUNTIES BY LATER THIS AFTERNOON WHERE A FEW HEAVIER/CONVECTIVE DOWNPOURS WILL BE POSSIBLE PER THIS MORNING`S HRRR/RAP PROGS. HIGH TEMPERATURES REFLECTIVE OF CLOUD COVERAGE...WITH ONE MORE WARM DAY IN THE UPPER 70S TO AROUND 80 FAR NORTH...THOUGH ONLY IN THE LOWER TO MID 70S CENTRAL/SOUTH AS CLOUDS ARRIVE EARLIER IN THE DAY. WINDS LIGHT TO MODERATE SOUTHERLY AND OCCASIONALLY GUSTY THIS AFTERNOON ESPECIALLY IN THE CHAMPLAIN VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AS OF 356 AM EDT WEDNESDAY...BY TONIGHT...INITIAL MOISTURE BAND AND ASSOCIATED RAIN SHOWERS WILL CONTINUE TO PIVOT NORTHWARD INTO THE REGION...THOUGH WEAKEN OVER TIME AS INSTABILITY WANES AND PBL TEMPERATURES COOL. HAVE MAINTAINED LIKELY (60%) POPS FOR OUR SOUTHERN AND EASTERN COUNTIES TO ACCOUNT FOR THESE TRENDS WITH LOWER VALUES NORTH AND WEST. BY LATER TONIGHT COVERAGE OF ACTIVITY SHOULD LESSEN WITH SOME PATCHY BR/FG FORMATION ACROSS THE MOUNTAINS AND EASTERN VERMONT. QPF TOTALS RANGING FROM A TENTH OF AN INCH OR SO NORTH AND WEST...TO LOCALLY A QUARTER TO A THIRD OF AN INCH SOUTH AND EAST. WITH AMPLE CLOUD COVER AND NEGLIGIBLE THERMAL ADVECTION...LOWS TO HOLD RELATIVELY MILD AND MAINLY IN THE 50S. BY THURSDAY INTO THURSDAY NIGHT UPPER LOW DRIFTS INTO THE REGION WHILE WEAKENING INTO AN OPEN WAVE OVER TIME AS IT CONTINUES TO PROGRESS NORTHEAST. DESPITE A FEW PEEKS OF SUN HERE AND THERE...IDEA WILL BE FOR PLENTY OF CLOUDS ALONG WITH A DECENT COVERAGE OF SHOWER ACTIVITY AND A FEW STORMS...WITH BEST COVERAGE DURING CONVECTIVE MAX PERIOD FROM EARLY AFTERNOON THROUGH EARLY EVENING. A QUICK LOOK AT SOUNDING PROFILES SHOW VERY LIGHT WINDS THROUGH THE PBL SO ACTIVITY WILL BE SLOW MOVING AND TEND TO DRIFT AROUND. SO WHILE AVERAGE QPF SHOULD ONLY BE IN THE 0.10 TO 0.30 INCH RANGE THERE COULD BE SCATTERED HEAVIER POINT TOTALS...ESPECIALLY IN THOSE AREAS RECEIVING HEAVIER CONVECTIVE DOWNPOURS. WCD VALUES QUITE LOW HOWEVER...SO ONLY AVERAGE PRECIP EFFICIENCY WILL EXIST IN CELL CORES AND CERTAINLY NO HYDRO CONCERNS GIVEN OUR RECENT DRY STRETCH. HIGHS COOLER BUT STILL SEASONABLY MILD...TOPPING OUT GENERALLY IN THE 65 TO 72 RANGE. LOWS THURSDAY NIGHT UPPER 40S TO LOWER 50S. BY FRIDAY MODELS REMAIN GOOD OVERALL CONSISTENCY IN SHOWING FIRST OF TWO COLD FRONTAL BOUNDARIES TO SLIDE INTO OUR REGION. A FRONTAL WAVE OF LOW PRESSURE WILL BE RIDING NORTHEAST DURING THE PERIOD AND THIS FEATURE WILL SLOW THE BOUNDARY...BRINGING A SOAKING THOUGH WELCOMED RAINFALL TO THE REGION BY THE AFTERNOON AND EVENING HOURS. SOME SUBTLE NORTH/SOUTH DIFFERENCES IN PLACEMENT OF HEAVIER QPF AXIS BUT OVERALL IDEA WILL BE FOR A WET AFTERNOON AND HIGHER/LIKELY POPS ACROSS OUR AREA. TEMPERATURES RANGING THROUGH THE 60S ACROSS NRN NY WHERE RAINFALL WILL ARRIVE EARLIER IN THE DAY...AND 65 TO 70 OR SO ACROSS VT. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 420 AM EDT WEDNESDAY...UNSETTLED WEATHER CONTINUES INTO THE LONG TERM WITH SFC LOW OVER THE NE GAINING MOMENTUM EWD...AS UPR LVL LOW/TROUGH PUSHES EAST INTO ERN ONTARIO FRIDAY NIGHT THROUGH SATURDAY. A BRIEF BREAK IN PRECIP MAY OCCUR LATE SATURDAY INTO SATURDAY NIGHT AS DRY SLOT TRIES TO REACH NWD INTO NRN NY AND VT AS THE FIRST SFC LOW WEAKENS AND SHIFTS EAST AND LOW ASSOCIATED WITH UPR TROUGH MOVES ACROSS JAMES BAY...DRAGGING A COLD FRONT WITH IT. THREAT OF PRECIP BEGINS TO TAPER OFF LATE SUNDAY WITH SFC RIDGING BEGINNING TO BUILD INTO WRN NY. COLDER AIR WILL FILTER IN WITH CONTINUED NW FLOW. NEXT THREAT FOR PRECIP WILL ARRIVE TUESDAY NIGHT. ABOVE NORMAL TEMPERATURES FOR THE BEGINNING OF THE PERIOD WILL TREND COOLER BEHIND THE COLD FRONT MOVING THROUGH FRIDAY NIGHT...WITH REINFORCED COLD AIR MOVING INTO THE NORTH COUNTRY SATURDAY NIGHT INTO SUNDAY. MIN TEMPS IN THE 40S FRIDAY AND SATURDAY NIGHT WILL COOL INTO THE 30S SUNDAY NIGHT THROUGH MONDAY NIGHT. DURING THE DAY...MAX TEMPS IN THE 60S ON SATURDAY AND SUNDAY WILL COOL INTO THE 50S MONDAY TO L60S ON TUESDAY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... THROUGH 12Z THURSDAY...MID AND HIGH LEVEL CLOUDS SPREADING NORTHWARD OVER SRN VT AND ADKS. VFR CONDITIONS WILL PERSIST THROUGH AT LEAST EARLY AFTN BEFORE A CLOSED UPR LOW LIFTING NORTH BRINGS SOME ISOLD/SCATTERED RAIN SHOWERS AND AN ISOLATED TSTM THIS AFTN INTO OVERNIGHT. EXPECT VFR SHOWERS TO START AT BTV...PBG...MPV...RUT...SLK AFT 20Z. MSS EXPECTING VCSH IN THE EVENING HOURS. ALL TAF SITES EXPECTING PERIOD OF MVFR CONDITIONS OVERNIGHT...MAINLY IN THE FORM OF LOW CIGS...BUT MPV...SLK AND MSS WILL HAVE LGTR WINDS AND LIKELY TO SEE SOME MVFR VSBYS FROM FG DEVELOPMENT. OUTLOOK 12Z THURSDAY THROUGH SUNDAY... 12Z THURSDAY ONWARD...CHANCE OF RAIN SHOWERS CONTINUE ACROSS THE REGION THROUGH FRIDAY NIGHT...WITH SOME MVFR CONDITIONS POSSIBLE IN RAIN SHOWERS. A COLD FRONT WILL MOVE INTO THE REGION ON FRIDAY AND THEN BECOME NEARLY STATIONARY...WITH A CHANCE OF RAIN SHOWERS FRIDAY AND SATURDAY...WITH SOME AREAS OF MVFR POSSIBLE. SUNDAY THE FRONT WILL GAIN MOMENTUM EASTWARD AS UPPER LEVEL LOW MOVES SOUTH OF JAMES BAY. && .FIRE WEATHER... A CHANGE IN THE WEATHER PATTERN WILL INCREASE THE CHANCES FOR SCATTERED RAIN SHOWERS TODAY THROUGH THIS UPCOMING WEEKEND. IN ADDITION... COOLER TEMPERATURES AND HIGHER RELATIVE HUMIDITY LEVELS CAN BE EXPECTED WITH A WIDESPREAD WETTING RAIN POSSIBLE FRIDAY INTO SATURDAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...KGM AVIATION...KGM FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
630 AM EDT WED MAY 8 2013 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL BRING INCREASING CLOUDS ALONG WITH A CHANCE OF SHOWERS AND COOLER TEMPERATURES TO THE REGION BY LATER TODAY INTO THURSDAY. A COLD FRONT WILL SWING INTO THE AREA BY FRIDAY INTO SATURDAY WITH A WIDESPREAD AND WELCOMED RAINFALL LIKELY. COOL AND MAINLY DRY WEATHER WILL RETURN BY SUNDAY INTO MONDAY OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 630 AM EDT WEDNESDAY...MODEST UPDATES TO DEWPOINTS THROUGH TODAY PER LATEST OBS AND RUC13 DATA. ALSO TWEAKED HOURLY TEMPERATURES OVER THE NEXT FEW HOURS TO ACCOUNT FOR CURRENT OBSERVATIONAL TRENDS. NO APPRECIABLE CHANGES TO WORDED FORECAST HOWEVER. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS... HIGH PRESSURE WHICH BROUGHT WARM AND DRY WEATHER TO THE REGION FOR OVER A WEEK WILL FINALLY SLIDE EAST AND ALLOW UPPER LEVEL LOW PRESSURE TO PUSH NORTHWARD FROM THE MID ATLANTIC STATES. THUS CLEAR/SUNNY SKIES THIS MORNING WILL GRADUALLY GIVE WAY TO THICKENING CLOUD COVER FROM THE SOUTH THROUGH THE MORNING AND AFTERNOON HOURS AS DEEPER MOISTURE SLOWLY PINWHEELS NORTH. HOWEVER DRY LOWER LEVELS WILL KEEP MOST PRECIPITATION CONFINED TO OUR CENTRAL AND SOUTHERN COUNTIES BY LATER THIS AFTERNOON WHERE A FEW HEAVIER/CONVECTIVE DOWNPOURS WILL BE POSSIBLE PER THIS MORNING`S HRRR/RAP PROGS. HIGH TEMPERATURES REFLECTIVE OF CLOUD COVERAGE...WITH ONE MORE WARM DAY IN THE UPPER 70S TO AROUND 80 FAR NORTH...THOUGH ONLY IN THE LOWER TO MID 70S CENTRAL/SOUTH AS CLOUDS ARRIVE EARLIER IN THE DAY. WINDS LIGHT TO MODERATE SOUTHERLY AND OCCASIONALLY GUSTY THIS AFTERNOON ESPECIALLY IN THE CHAMPLAIN VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AS OF 356 AM EDT WEDNESDAY...BY TONIGHT...INITIAL MOISTURE BAND AND ASSOCIATED RAIN SHOWERS WILL CONTINUE TO PIVOT NORTHWARD INTO THE REGION...THOUGH WEAKEN OVER TIME AS INSTABILITY WANES AND PBL TEMPERATURES COOL. HAVE MAINTAINED LIKELY (60%) POPS FOR OUR SOUTHERN AND EASTERN COUNTIES TO ACCOUNT FOR THESE TRENDS WITH LOWER VALUES NORTH AND WEST. BY LATER TONIGHT COVERAGE OF ACTIVITY SHOULD LESSEN WITH SOME PATCHY BR/FG FORMATION ACROSS THE MOUNTAINS AND EASTERN VERMONT. QPF TOTALS RANGING FROM A TENTH OF AN INCH OR SO NORTH AND WEST...TO LOCALLY A QUARTER TO A THIRD OF AN INCH SOUTH AND EAST. WITH AMPLE CLOUD COVER AND NEGLIGIBLE THERMAL ADVECTION...LOWS TO HOLD RELATIVELY MILD AND MAINLY IN THE 50S. BY THURSDAY INTO THURSDAY NIGHT UPPER LOW DRIFTS INTO THE REGION WHILE WEAKENING INTO AN OPEN WAVE OVER TIME AS IT CONTINUES TO PROGRESS NORTHEAST. DESPITE A FEW PEEKS OF SUN HERE AND THERE...IDEA WILL BE FOR PLENTY OF CLOUDS ALONG WITH A DECENT COVERAGE OF SHOWER ACTIVITY AND A FEW STORMS...WITH BEST COVERAGE DURING CONVECTIVE MAX PERIOD FROM EARLY AFTERNOON THROUGH EARLY EVENING. A QUICK LOOK AT SOUNDING PROFILES SHOW VERY LIGHT WINDS THROUGH THE PBL SO ACTIVITY WILL BE SLOW MOVING AND TEND TO DRIFT AROUND. SO WHILE AVERAGE QPF SHOULD ONLY BE IN THE 0.10 TO 0.30 INCH RANGE THERE COULD BE SCATTERED HEAVIER POINT TOTALS...ESPECIALLY IN THOSE AREAS RECEIVING HEAVIER CONVECTIVE DOWNPOURS. WCD VALUES QUITE LOW HOWEVER...SO ONLY AVERAGE PRECIP EFFICIENCY WILL EXIST IN CELL CORES AND CERTAINLY NO HYDRO CONCERNS GIVEN OUR RECENT DRY STRETCH. HIGHS COOLER BUT STILL SEASONABLY MILD...TOPPING OUT GENERALLY IN THE 65 TO 72 RANGE. LOWS THURSDAY NIGHT UPPER 40S TO LOWER 50S. BY FRIDAY MODELS REMAIN GOOD OVERALL CONSISTENCY IN SHOWING FIRST OF TWO COLD FRONTAL BOUNDARIES TO SLIDE INTO OUR REGION. A FRONTAL WAVE OF LOW PRESSURE WILL BE RIDING NORTHEAST DURING THE PERIOD AND THIS FEATURE WILL SLOW THE BOUNDARY...BRINGING A SOAKING THOUGH WELCOMED RAINFALL TO THE REGION BY THE AFTERNOON AND EVENING HOURS. SOME SUBTLE NORTH/SOUTH DIFFERENCES IN PLACEMENT OF HEAVIER QPF AXIS BUT OVERALL IDEA WILL BE FOR A WET AFTERNOON AND HIGHER/LIKELY POPS ACROSS OUR AREA. TEMPERATURES RANGING THROUGH THE 60S ACROSS NRN NY WHERE RAINFALL WILL ARRIVE EARLIER IN THE DAY...AND 65 TO 70 OR SO ACROSS VT. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 420 AM EDT WEDNESDAY...UNSETTLED WEATHER CONTINUES INTO THE LONG TERM WITH SFC LOW OVER THE NE GAINING MOMENTUM EWD...AS UPR LVL LOW/TROUGH PUSHES EAST INTO ERN ONTARIO FRIDAY NIGHT THROUGH SATURDAY. A BRIEF BREAK IN PRECIP MAY OCCUR LATE SATURDAY INTO SATURDAY NIGHT AS DRY SLOT TRIES TO REACH NWD INTO NRN NY AND VT AS THE FIRST SFC LOW WEAKENS AND SHIFTS EAST AND LOW ASSOCIATED WITH UPR TROUGH MOVES ACROSS JAMES BAY...DRAGGING A COLD FRONT WITH IT. THREAT OF PRECIP BEGINS TO TAPER OFF LATE SUNDAY WITH SFC RIDGING BEGINNING TO BUILD INTO WRN NY. COLDER AIR WILL FILTER IN WITH CONTINUED NW FLOW. NEXT THREAT FOR PRECIP WILL ARRIVE TUESDAY NIGHT. ABOVE NORMAL TEMPERATURES FOR THE BEGINNING OF THE PERIOD WILL TREND COOLER BEHIND THE COLD FRONT MOVING THROUGH FRIDAY NIGHT...WITH REINFORCED COLD AIR MOVING INTO THE NORTH COUNTRY SATURDAY NIGHT INTO SUNDAY. MIN TEMPS IN THE 40S FRIDAY AND SATURDAY NIGHT WILL COOL INTO THE 30S SUNDAY NIGHT THROUGH MONDAY NIGHT. DURING THE DAY...MAX TEMPS IN THE 60S ON SATURDAY AND SUNDAY WILL COOL INTO THE 50S MONDAY TO L60S ON TUESDAY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... THROUGH 06Z THURSDAY...VFR CONDITIONS WILL PERSIST THROUGH THE REST OF THE NIGHT AND FOR THE FIRST HALF OF WEDNESDAY BEFORE A CLOSED UPR LOW ACROSS THE MID-ATLANTIC STATES GRADUALLY LIFTS NWD...BRINGING SOME ISOLD/SCATTERED RAIN SHOWERS AND AN ISOLATED TSTM THIS AFTN INTO EVENING. CLDS INCREASING FROM THE SOUTH LATE THIS MORNING FOLLOWED BY VFR SHOWERS AT BTV...MPV...RUT...SLK AFT 20/21Z. WITH VFR SHOWERS AT PBG AFTER 00Z AS LOW-LEVELS QUITE DRY TO START SO COVERAGE OF ACTIVITY SHOULD BE SLOW TO DEVELOP NWD DURING WED AFTN AND EVENING. MSS EXPECTING VCSH IN THE EVENING HOURS. SOME MVFR CIGS EXPECTED AT KMPV IN THE LATE EVENING. EXPECT WINDS DURING THE DAYLIGHT HRS WEDNESDAY WILL GENERALLY BE SSE 10-15 KTS WITH INCREASING GRADIENT FLOW AND SOME GUSTS OF 15-20 KTS. WINDS EXPECTED TO SUBSIDE OVERNIGHT WEDNESDAY NIGHT TO LESS THAN 10KTS. OUTLOOK 06Z THURSDAY THROUGH SUNDAY... 06Z THURSDAY ONWARD...CHANCE OF RAIN SHOWERS CONTINUE ACROSS THE REGION WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...WITH SOME MVFR CONDITIONS POSSIBLE IN RAIN SHOWERS. A COLD FRONT WILL MOVE INTO THE REGION ON FRIDAY AND THEN BECOME NEARLY STATIONARY...WITH A CHANCE OF RAIN SHOWERS FRIDAY AND SATURDAY...WITH SOME AREAS OF MVFR POSSIBLE. SUNDAY THE FRONT WILL GAIN MOMENTUM EASTWARD AS UPPER LEVEL LOW MOVES SOUTH OF JAMES BAY. && .FIRE WEATHER... A CHANGE IN THE WEATHER PATTERN WILL INCREASE THE CHANCES FOR SCATTERED RAIN SHOWERS TODAY THROUGH THIS UPCOMING WEEKEND. IN ADDITION... COOLER TEMPERATURES AND HIGHER RELATIVE HUMIDITY LEVELS CAN BE EXPECTED WITH A WIDESPREAD WETTING RAIN POSSIBLE FRIDAY INTO SATURDAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...KGM AVIATION...KGM FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1050 AM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY. && .NEAR TERM /THROUGH THURSDAY NIGHT/... AS OF 1050 AM WEDNESDAY... MORNING UPDATE AS OF 1050 AM EDT: CURRENT SATELLITE SHOWS A VORTICITY MAX EMBEDDED WITHIN THE LARGER CLOSED LOW SLOWLY DRIFTING SE ACROSS ERN WVA. THE LEADING EDGE OF RAIN AHEAD OF THIS FEATURE IS NOW APPROACHING OUR NW ZONES. LATEST HRRR HAS A DECENT HANDLE ON THIS RAIN AND TIMING...AND SHOWS IT MOVING ACROSS OUR NORTHERN ZONES WHILE DIMINISHING IN COVERAGE THROUGH EARLY/MID AFTERNOON. MEANWHILE ADDITIONAL CONVECTIVE CELLS ARE SHOWN IN THE HRRR DEVELOPING ACROSS THE FOOTHILLS DURING THE EARLY AFTERNOON THEN MOVING EASTWARD ACROSS OUR PIEDMONT ZONES THROUGH 00Z. LATEST VIS SATELLITE SHOWS THE BEST OPPORTUNITY FOR SUNSHINE AND SFC HEATING ACROSS THE SOUTHERN HALF OF OUR CWA...THUS LENDING SUPPORT TO THE MODEL DEPICTION OF CONVECTIVE CELL DEVELOPMENT LATER THIS AFTERNOON. HOWEVER...FORECAST SOUNDINGS FOR LATER TODAY SUGGEST MID AND UPPER LEVEL WARMING AS THE UPPER LOW LIFTS NE...AND SHOULD LIMIT OVERALL CAPE AND TSTM/SEVERE POTENTIAL. IF VIGOROUS TSTM UPDRAFTS CAN DEVELOP...CAN`T RULE OUT SOME SMALL HAIL AND PERHAPS BRIEF/ISOLATED STRONG WIND GUSTS WITH ANY OF THE MORE POTENT CELLS. OTHERWISE...WITH EXTENSIVE CLOUDS AND LIGHT RAIN ACROSS OUR NORTHERN ZONES...TEMPS HAVE BEEN SLOWER TO RISE THERE...SO WILL MAKE A FEW SUBTLE DOWNWARD TWEAKS THERE FOR AFTERNOON TEMPS. LOOK FOR HIGHS TODAY TO RANGE FROM THE UPPER 60S NORTH TO MID 70S SOUTH. PREV NEAR TERM DISC ISSUED 310 AM EDT: ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY. FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND WRN PIEDMONT. THE MID-UPPER LEVEL LOW THAT HAS PLAGUED THE REGION FOR DAYS IS LOCATED AROUND RNK EARLY THIS MORNING... AND IS EXPECTED TO DRIFT TOWARD THE NNE ALONG THE ERN SLOPES OF THE APPALACHIANS INTO PA TONIGHT. ABOVE-NORMAL PRECIP WATER WILL CONTINUE TO ROTATE ABOUT THE NEARLY STACKED CYCLONE... AND MODELS SHOW OVERALL PRECIP WATER INCREASING FROM JUST UNDER AN INCH THIS MORNING TO NEARLY 1.2 INCHES -- CLOSE TO 150% OF NORMAL -- OVER CENTRAL/ERN NC THIS AFTERNOON. WITH LOW LEVEL WARM AIR ADVECTION AND THE POCKET OF SLIGHTLY COOLER MID LEVEL TEMPS OVER NRN/WRN NC... EXPECT THE COLUMN TO DESTABILIZE BY AFTERNOON... AND BOTH THE NAM AND RAP MODELS SHOW MLCAPE INCREASING TO 600-1200 J/KG LATER TODAY SPREADING IN FROM THE SW. AS THE LOW ALOFT LIFTS AWAY FROM NC... MID LEVEL FLOW STRENGTHENS QUICKLY FROM LESS THAN 20 KTS EARLY THIS MORNING TO 35-40 KTS FROM THE W AND WNW THIS AFTERNOON... AND THIS SHOULD FOSTER STORM ORGANIZATION DESPITE THE MARGINAL INSTABILITY. DYNAMIC SUPPORT FROM VORTICITY LOBES ROTATING AROUND THE LOW AS WELL AS A QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A NORTHWESTERLY 50-KT UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD ALSO ENCOURAGE STORM DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED SHOWERS FINISH THEIR JOURNEY THROUGH CENTRAL NC THIS MORNING... EXPECTED SCATTERED SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE HIGHER TERRAIN OF NW NC INTO THE TRIAD REGION... THEN INCREASING IN COVERAGE AS THEY PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC DURING THE AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC WRF. GIVEN THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD BECOME STRONG WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH WILL DEPEND ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND THIS IN TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD COVER PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE CLOUDS AND SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND QUICKLY RISING CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS. EXPECT HIGHS FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE AND FACTORING IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE MEAGER DYNAMIC SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID LEVEL LOW... AND WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL AFTER NIGHTFALL ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL FLOW AND DRYING... SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT... FOLLOWED BY GRADUAL CLEARING WEST TO EAST. LOWS 53-58. FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 315 AM WEDNESDAY... SPLIT FLOW PATTERN OVER THE CONUS LATE THIS WEEK WILL BECOME DOMINATED BY THE NORTHERN STREAM BY THIS WEEKEND AS A STRONG SHORTWAVE BEGINS TO CARVE OUT A DEEP TROUGH OVER THE EASTERN US. AHEAD OF THIS SYSTEM...RIDGING OVER OUR REGION WILL WEAKEN AS A LEAD SHORTWAVE MOVES THROUGH THE MIDWEST STATES. THE ASSOCIATED FRONTAL ZONE WILL MOVE SLOWLY TO THE EAST AND APPROACH THE APPALACHIANS SATURDAY. THE MORE UNSTABLE WARM SECTOR AIRMASS WILL BE WEST OF THE MOUNTAINS ON FRIDAY...ALTHOUGH FORECAST SOUNDINGS SUGGEST MLCAPE MAY REACH 500-1000 J/KG FRIDAY AFTERNOON AS THE UPPER RIDGE WEAKENS. DEEP LAYER SOUTHWESTERLY FLOW SHOULD BE RELATIVELY WEAK...MAKING IT DIFFICULT FOR MUCH MORE THAN A FEW ISOLATED STORMS TO MOVE INTO THE WESTERN PIEDMONT. FRIDAY WILL BE THE WARMEST DAY OF THE PERIOD WITH PARTLY CLOUDY TO MOSTLY SUNNY SKIES. LOW LEVEL THICKNESSES SURPASSING 1390M AND A SOUTHWESTERLY WIND SUGGEST HIGHS IN THE LOW TO MID 80S. LOWS FRIDAY NIGHT IN THE LOW TO MID 60S. GRADUAL HEIGHT FALLS AHEAD OF THE AFOREMENTIONED UPPER TROUGH MOVING SOUTH OUT OF CANADA WILL HELP TO SHARPEN THE LEE TROUGH SATURDAY AS A THE COLD FRONT APPROACHES FROM THE WEST. WITH WEAK TO MODERATE INSTABILITY POSSIBLE...DEPENDING ON THE AMOUNT REGIONAL CLOUD COVER SATURDAY MORNING....AND DEEP LAYER SHEAR INCREASING TO AROUND 30KT...THERE WILL BE A BETTER CHANCE OF STRONG STORMS SATURDAY AFTERNOON. HIGHS 76-83 WEST TO EAST. EVEN WITH THE LOSS OF HEATING SATURDAY NIGHT...SOME CONVECTION SHOULD STILL BE ABLE TO PERSIST AS THE LEAD FRONTAL ZONE MOVES INTO CENTRAL NC. WILL MAINTAIN A CHANCE POP THROUGH THE OVERNIGHT HOURS...WITH LOWS IN THE LOW TO MID 60S. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 315 AM WEDNESDAY... THE COLD FRONT CROSSING THE AREA SATURDAY NIGHT SHOULD EFFECTIVELY SHIFT TO THE COASTAL PLAIN SUNDAY MORNING...WHILE A SECONDARY AND STRONGER POLAR FRONT SWINGS INTO THE AREA FROM THE NORTHWEST. CHANCES OF PRECIP WILL BE PRIMARILY FOCUSED OVER THE COASTAL PLAIN WHERE ANY APPRECIABLE INSTABILITY WOULD BE MORE LIKELY. HIGHS BEGIN THEIR MORE SIGNIFICANT DOWNWARD TREND SUNDAY AND PARTICULARLY MONDAY AS THE AFOREMENTIONED POLAR FRONT CROSSES THE AREA AND A DEEP UPPER TROUGH DEVELOPS OVER THE EASTERN US. HIGHS IN THE MID 70S SUNDAY WILL FALL WELL BELOW NORMAL INTO THE MID TO UPPER 60S MONDAY AND TUESDAY. THERE IS MEDIUM TO HIGH CONFIDENCE IN THESE BELOW NORMAL TEMPS AND DRY CONDITIONS DURING THE FIRST PART OF NEXT WEEK.. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 645 AM WEDNESDAY... SUB-VFR CIGS DEVELOPED OVERNIGHT AT INT/GSO -- IFR AT INT AND MVFR AT GSO -- WHILE VFR CONDITIONS HAVE DOMINATED AT RDU/RWI/FAY. MVFR CONDITIONS SHOULD HOLD AT INT/GSO FOR A FEW MORE HOURS THIS MORNING BEFORE LIFTING TO VFR BY AROUND 16Z... WHILE VFR CONDITIONS SHOULD PERSIST AT RDU/RWI/FAY THROUGH THE MORNING. ISOLATED SHOWERS NEAR RDU/RWI THROUGH 14Z SHOULD HAVE NO ADVERSE IMPACT. SCATTERED SHOWERS AND STORMS ARE EXPECTED TO DEVELOP WEST OF THE TRIAD TOWARD MIDDAY AND AFFECT INT/GSO MAINLY FROM 16Z-20Z... RDU MAINLY FROM 17Z-21Z... AND RWI/FAY MAINLY FROM 19Z-23Z AS THE SHOWERS/STORMS MOVE ESE ACROSS THE AREA AND INCREASE IN COVERAGE. A PERIOD OF MVFR-IFR CIGS/VSBYS IN AND NEAR SHOWERS/STORMS IS LIKELY... OTHERWISE VFR CONDITIONS ARE EXPECTED TO DOMINATE THROUGH TONIGHT WITH SKIES PARTIALLY CLEARING LATE. LOOKING BEYOND 12Z TONIGHT: VFR CONDITIONS SHOULD DOMINATE INTO SATURDAY MORNING WITH HIGH PRESSURE STRETCHING OVER THE SOUTHEAST UNITED STATES. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF SUB-VFR CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...NP/HARTFIELD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...HARTFIELD
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1021 AM CDT WED MAY 8 2013 .UPDATE... THE MCV CURRENTLY CENTERED OVER DENTON COUNTY WILL GRADUALLY WEAKEN AS IT PROPAGATES EAST ACROSS NORTH TEXAS. AREAS OF LIGHT PRECIPITATION WITH THE OCCASIONAL LIGHTNING STRIKE CAN BE EXPECTED EAST OF THIS FEATURE THROUGH EARLY AFTERNOON. WENT AHEAD AND EXTENDED THE ISOLATED THUNDER OVER THE NORTHEASTERN HALF OF NORTH TEXAS FOR A FEW HOURS BASED ON THE LATEST RADAR AND SATELLITE TRENDS...OTHERWISE NO SIGNIFICANT CHANGES ARE PLANNED THIS MORNING. 30 && .AVIATION... SCATTERED SMALL SHOWERS AND A FEW THUNDERSTORMS WERE NEAR AND AHEAD OF A MESOSCALE CONVECTIVE VORTEX /MCV/ CENTERED ABOUT 20 MILES NORTHWEST OF KMWL /MINERAL WELLS/. LIFT ASSOCIATED WITH THIS FEATURE WILL BRING A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS TO THE METROPLEX THIS MORNING AS IT MOVES EAST OR EAST NORTHEAST AT 20 MPH. THE CHANCES OF A THUNDERSTORM AT THE METROPLEX TAF SITES IS TOO LOW TO MENTION...BUT WILL INCLUDE A VCSH FOR THE 12-16Z PERIOD. OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH MIDNIGHT TONIGHT. LOW CLOUDS ARE EXPECTED TO DEVELOP ACROSS SOUTH TEXAS OVERNIGHT...AND SPREAD NORTH INTO THE WACO AREA AFTER 06Z TONIGHT... AND INTO THE METROPLEX AROUND 08Z. MVFR CEILINGS ARE EXPECTED AND SOME LIGHT FOG /5SM BR/ IS POSSIBLE FOR THE 08Z-16Z THURSDAY PERIOD. SOUTHERLY WINDS OF 5 TO 10 KNOTS EARLY THIS MORNING WILL INCREASE TO AROUND 15 KNOTS BEFORE MIDDAY...WITH GUSTS TO AROUND 25 KNOTS LIKELY. THUNDERSTORMS THAT ARE EXPECTED TO DEVELOP ALONG THE DRYLINE LATE THIS AFTERNOON ARE FORECAST TO DISSIPATE AS THEY APPROACH THE I-35 CORRIDOR LATE TONIGHT. 58 && .PREV UPDATE... .UPDATE... MCV WHICH WAS MOVING OUT OF THROCKMORTON COUNTY EARLIER IS NOW CENTERED ALONG THE PALO PINTO/JACK COUNTY LINE AND SEEMS TO BE AIDING IN MESOSCALE ASCENT ON ITS EAST SIDE. THIS ALSO CORRESPONDS WELL WITH LEADING EDGE OF THE 850MB THETA-E AXIS WHICH CONTINUES TO SPREAD NORTHEAST. ISOLATED THUNDERSTORMS CONTINUE AT THIS HOUR AND HAVE INCREASED SLIGHTLY IN COVERAGE. WILL UPDATE QUICKLY TO MENTION ISOLATED THUNDERSTORMS THROUGH MID MORNING A LITTLE FARTHER EAST. NO CHANGES TO POPS. GIVEN THE SMALL CELLS...WILL LEAVE POPS AT 10 PERCENT. DUNN && .PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/ AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR THIS ACTIVITY. LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z. MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN THREAT WITH THUNDERSTORMS THROUGH THIS EVENING. THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA. THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON. HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF THE AREA. BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT WEEK. TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS THROUGH THE NEXT 7 DAYS. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20 WACO, TX 86 63 83 64 83 / 10 10 50 70 30 PARIS, TX 85 59 79 62 79 / 10 10 30 50 20 DENTON, TX 85 63 83 62 80 / 10 10 40 60 20 MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20 DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20 TERRELL, TX 85 62 81 63 82 / 10 10 40 60 30 CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30 TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30 MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
627 AM CDT WED MAY 8 2013 .AVIATION... SCATTERED SMALL SHOWERS AND A FEW THUNDERSTORMS WERE NEAR AND AHEAD OF A MESOSCALE CONVECTIVE VORTEX /MCV/ CENTERED ABOUT 20 MILES NORTHWEST OF KMWL /MINERAL WELLS/. LIFT ASSOCIATED WITH THIS FEATURE WILL BRING A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS TO THE METROPLEX THIS MORNING AS IT MOVES EAST OR EAST NORTHEAST AT 20 MPH. THE CHANCES OF A THUNDERSTORM AT THE METROPLEX TAF SITES IS TOO LOW TO MENTION...BUT WILL INCLUDE A VCSH FOR THE 12-16Z PERIOD. OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH MIDNIGHT TONIGHT. LOW CLOUDS ARE EXPECTED TO DEVELOP ACROSS SOUTH TEXAS OVERNIGHT...AND SPREAD NORTH INTO THE WACO AREA AFTER 06Z TONIGHT... AND INTO THE METROPLEX AROUND 08Z. MVFR CEILINGS ARE EXPECTED AND SOME LIGHT FOG /5SM BR/ IS POSSIBLE FOR THE 08Z-16Z THURSDAY PERIOD. SOUTHERLY WINDS OF 5 TO 10 KNOTS EARLY THIS MORNING WILL INCREASE TO AROUND 15 KNOTS BEFORE MIDDAY...WITH GUSTS TO AROUND 25 KNOTS LIKELY. THUNDERSTORMS THAT ARE EXPECTED TO DEVELOP ALONG THE DRYLINE LATE THIS AFTERNOON ARE FORECAST TO DISSIPATE AS THEY APPROACH THE I-35 CORRIDOR LATE TONIGHT. 58 && .UPDATE... MCV WHICH WAS MOVING OUT OF THROCKMORTON COUNTY EARLIER IS NOW CENTERED ALONG THE PALO PINTO/JACK COUNTY LINE AND SEEMS TO BE AIDING IN MESOSCALE ASCENT ON ITS EAST SIDE. THIS ALSO CORRESPONDS WELL WITH LEADING EDGE OF THE 850MB THETA-E AXIS WHICH CONTINUES TO SPREAD NORTHEAST. ISOLATED THUNDERSTORMS CONTINUE AT THIS HOUR AND HAVE INCREASED SLIGHTLY IN COVERAGE. WILL UPDATE QUICKLY TO MENTION ISOLATED THUNDERSTORMS THROUGH MID MORNING A LITTLE FARTHER EAST. NO CHANGES TO POPS. GIVEN THE SMALL CELLS...WILL LEAVE POPS AT 10 PERCENT. DUNN && .PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/ AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR THIS ACTIVITY. LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z. MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN THREAT WITH THUNDERSTORMS THROUGH THIS EVENING. THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA. THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON. HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF THE AREA. BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT WEEK. TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS THROUGH THE NEXT 7 DAYS. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20 WACO, TX 86 63 83 64 83 / 10 10 50 70 30 PARIS, TX 85 59 79 62 79 / 5 10 30 50 20 DENTON, TX 85 63 83 62 80 / 10 10 40 60 20 MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20 DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20 TERRELL, TX 85 62 81 63 82 / 5 10 40 60 30 CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30 TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30 MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 58/91
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
548 AM CDT WED MAY 8 2013 .UPDATE... MCV WHICH WAS MOVING OUT OF THROCKMORTON COUNTY EARLIER IS NOW CENTERED ALONG THE PALO PINTO/JACK COUNTY LINE AND SEEMS TO BE AIDING IN MESOSCALE ASCENT ON ITS EAST SIDE. THIS ALSO CORRESPONDS WELL WITH LEADING EDGE OF THE 850MB THETA-E AXIS WHICH CONTINUES TO SPREAD NORTHEAST. ISOLATED THUNDERSTORMS CONTINUE AT THIS HOUR AND HAVE INCREASED SLIGHTLY IN COVERAGE. WILL UPDATE QUICKLY TO MENTION ISOLATED THUNDERSTORMS THROUGH MID MORNING A LITTLE FARTHER EAST. NO CHANGES TO POPS. GIVEN THE SMALL CELLS...WILL LEAVE POPS AT 10 PERCENT. DUNN && .PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/ AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR THIS ACTIVITY. LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z. MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN THREAT WITH THUNDERSTORMS THROUGH THIS EVENING. THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA. THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON. HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF THE AREA. BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT WEEK. TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS THROUGH THE NEXT 7 DAYS. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20 WACO, TX 86 63 83 64 83 / 10 10 50 70 30 PARIS, TX 85 59 79 62 79 / 5 10 30 50 20 DENTON, TX 85 63 83 62 80 / 10 10 40 60 20 MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20 DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20 TERRELL, TX 85 62 81 63 82 / 5 10 40 60 30 CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30 TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30 MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1057 AM MDT WED MAY 8 2013 .UPDATE... && .SHORT TERM...WATER VAPOR LOOPS SHOW UPPER LOW OVER SOUTHERN UTAH AND NORTHERN ARIZONA WITH EASTERLY WINDS ACROSS MUCH OF COLORADO. MOISTURE CONTINUES TO STREAM NORTHWARD ACROSS CWA. SHOWERS HAVE ALREADY DEVELOPED ACROSS PORTIONS OF THE CWA IN THE MOIST EASTERLY FLOW. ALSO SOME THUNDERSTORMS ACROSS SOUTHERN SECTIONS OF THE DENVER AREA AND OVER THE PALMER DIVIDE. CURRENTLY THE BULK OF THE PRECIPITATION IS FALLING ACROSS THE MOUNTAINS AND FOOTHILLS SOUTH OF INTERSTATE 70...WITH SCATTERED SHOWERS OVER THE URBAN CORRIDOR. WEB CAMS ACROSS MOUNTAINS AND FOOTHILLS INDICATING SOME RAIN MIXED WITH THE SNOW...APPEARS THE SNOW LEVEL IS AROUND 8500 FEET. NEXT BATCH OF PRECIPITATION MOVING NORTH ACROSS EL PASO COUNTY...SHOULD BE MOVING ACROSS THE PALMER DIVIDE SHORTLY. OVERALL CURRENT FORECASTS SEEM IN ORDER FOR THIS AFTERNOON AND EVENING...ALREADY MADE ADJUSTMENTS EARLIER TO INCLUDE THUNDER. STILL SOME CONCERN FOR FLASH FLOOD POTENTIAL ALONG FOOTHILLS DUE TO THE WEAK STORM MOTION THOUGH OVERALL THREAT STILL SEEMS TOO LOW FOR A FLASH FLOOD WATCH. WILL CONTINUE TO MONITOR. SOME OF THE STORMS COULD PRODUCE SMALL HAIL AS RAP STILL SHOWING CAPES FROM 500-1000 J/KG INTO THE EVENING...NOT EXPECTING SEVERE STORMS AT THIS POINT. LASTLY...WILL CONTINUE WITH THE ADVISORY FOR ZONE 34. STILL LOOKING AT SOME POTENTIAL FOR HEAVY SNOW ABOVE 10000 FEET...MAINLY DUE TO THE CONVECTION RATHER THAN OROGRAPHICS. WILL CONTINUE TO MONITOR TO SEE WHAT DEVELOPS FOR THE OVERNIGHT. WILL ALSO KEEP AN EYE ON ZONE 37 FOR THIS EVENING AS THERE IS SOME POTENTIAL FOR SOUTHEAST WINDS WHICH COULD BRING MORE LOW LEVEL MOISTURE INTO SOUTH PARK. .AVIATION...FIRST BATCH OF SHOWERS DEVELOPED ACROSS THE AREA AIRPORTS WITH SOME THUNDER REPORTED AT KAPA. A FEW SHOWERS STILL IN THE VICINITY. CEILINGS HAVE IMPROVED AFTER THE SHOWERS MOVED THROUGH. NEXT BATCH OF SHOWERS MOVING NORTH INTO DOUGLAS AND ELBERT COUNTIES...WILL BE MOVING INTO THE DENVER AREA IN THE NEXT TWO HOURS. SOME EMBEDDED THUNDERSTORMS WITH THE BATCH OF SHOWERS. ILS CONDITIONS PROBABLE WITH THE SHOWERS ALONG WITH POSSIBLE MVFR CEILINGS. OVERALL CURRENT TAF TRENDS SEEM ON TRACK...WILL MAKE SOME ADJUSTMENTS TO TIMING THE ONSET OF PRECIPITATION. WINDS TO SHIFT TO THE NORTHEAST DURING THE AFTERNOON...BUT WILL BE ERRATIC AND GUSTY NEAR THE SHOWERS AND STORMS WITH POSSIBLE GUSTS TO 25 OR 30 KTS. && .HYDROLOGY...RAIN SHOWERS ALONG WITH EMBEDDED THUNDERSTORMS EXPECTED THIS AFTERNOON. SOME CONCERN STILL EXISTS FOR THE POTENTIAL FOR HEAVY RAIN DUE TO SLOW STORM MOTIONS. THREAT LOOKS LOCALIZED...BUT BURN AREAS WILL NEED TO BE MONITORED. STRONGER STORMS MAY PRODUCE UP TO AN INCH IN AN HOUR. && .PREV DISCUSSION... /ISSUED 335 AM MDT WED MAY 8 2013/ SHORT TERM...WATER VAPOR IMAGERY SHOWING THE BROAD UPPER LOW MOVING SLOWLY EAST ACROSS THE SOUTHERN UTAH AND NORTHERN ARIZONA BORDER EARLY THIS AM. MODELS ARE FAIRLY CONSISTENT ON TRACKING THE LOW TO THE 4 CORNERS REGION BY THIS AFTERNOON THEN THE LOW SLOWLY WEAKENS AND REMAINS RATHER STATIONARY TONIGHT. QG FIELDS SHOWING INCREASING ASCENT AT ALL LEVELS OVER NORTHERN COLORADO THIS AFTERNOON WHILE WEAK...YET DEEPENING UPSLOPE FLOW BECOMES ESTABLISHED LATER TODAY AND TONIGHT OVER THE FRONT RANGE. CURRENTLY...MOST OF THE CWA IS PRECIP FREE BUT WEATHER WILL BE CHANGING TOWARDS MID MORNING AND AFTERNOON. RADAR AND OBSERVATIONS SHOWING PRECIP INCREASING OVER SOUTHERN AND SOUTHWEST COLORADO WITH SOME LIGHTNING OVER SOUTHWEST CO. THERE IS THUNDER POTENTIAL OVER ALL CWA TODAY AND EVEN NAM/RUC SHOWING SFC BASED CAPES FROM 500-1000J/KG BY AFTERNOON GIVEN LOWER 60S TEMPERATURES AND LOWER 40S DEWPOINTS. THE OVERALL SEVERE POTENTIAL IS LOW BUT GIVEN CAPES AND LOW FREEZING LEVELS...CERTAINLY SMALL HAIL POSSIBLE ALONG WITH HEAVY RAIN. A BIT CONCERNED ABOUT FIRE BURN SCARS WITH FLASH FLOOD POTENTIAL GIVEN WEAK STORM MOTIONS AND POTENTIAL FOR ECHO TRAINING. STILL OVERALL THREAT SEEMS TOO LOW TO ISSUE A FLASH FLOOD WATCH AT THIS TIME. CERTAINLY THESE AREAS WILL NEED TO BE WATCHED CLOSELY AS LAST EVENING STORMS WERE DUMPING QUITE A BIT OF RAIN IN ISOLATED SPOTS. WILL HAVE LIKELY POPS IN MOST LOCALES FOR THIS AFTERNOON AND INTO TONIGHT. AS FOR THE MOUNTAINS...THERE IS SOME SNOW POTENTIAL ESPECIALLY OVER ZONE 34. FORECAST FREEZING LEVELS WILL KEEP SNOW ABOVE 9000 FEET WITH ANY HEAVY SNOW MAINLY ABOVE 10000 FEET. HAVE DECIDED TO ISSUE A ADVISORY FOR NOW BUT CERTAINLY POTENTIAL FOR HEAVIER SNOWFALL IS POSSIBE. GIVEN THE WEAKENING NATURE OF THE LOW AND UNCERTAIN AREAL COVERAGE NOT READY TO GO WITH A WARNING. WILL LATE THE DAY SHIFT TAKE ANOTHER LOOK ON HOW THINGS ARE EVOLVING. LONG TERM...THE UPPER LOW OVER THE FOUR CORNERS WILL DEEPEN INTO THE SOUTHWEST STATES TO BEGIN PULLING AWAY FROM COLORADO. SURFACE HIGH PRESSURE PUSHING IN FROM THE NORTHERN GREAT PLAINS TO KEEP MOISTURE FOCUSED AGAINST THE SOUTHERN FOOTHILLS AND CENTRAL MOUNTAINS. WILL HAVE THE WINTER WEATHER ADVISORY GOING THROUGH THE AFTERNOON AS SNOW LEVELS WILL BEGIN AROUND 8500-9000 FT THURSDAY MORNING THEN SLOWLY RAISE TO AROUND 10000 IN THE AFTERNOON AS THE SNOW AND RAIN IS DIMINISHING. EXPECT ANOTHER 2-4 INCHES AT ELEVATIONS ABOVE 9500 THURSDAY OVER THE MOUNTAINS OF PARK...SUMMIT AND CLEAR CREEK COUNTIES. RAIN WILL BE CONTINUING AT LOWER ELEVATIONS THURSDAY WITH A FEW ISOLATED TSTORMS POSSIBLE. TEMPERATURES THURSDAY WILL LIKELY STAY IN THE 50S OVER THE PLAINS WITH SLIGHTLY WARMER WEATHER OUT ON THE FAR NORTHEASTERN PLAINS FURTHER AWAY FROM THE UPSLOPE EFFECTS. MOUNTAINS WILL REACH INTO THE 40S WITH NORTH AND MIDDLE PARKS REACHING THE 50S. THURSDAY NIGHT ALL THE PRECIPITATION WILL BE DIMINISHING NORTH TO SOUTH WITH CLEARING SKIES AND DIMINISHING WINDS. FRIDAY AND SATURDAY WILL FEATURE SHOWERS EACH DAY AND A SLIGHT CHANCE OF A THUNDERSTORM OR TWO. FRIDAY WILL WARM AROUND 5-8 DEGREES...THEN A COOL PUSH ARRIVES FOR SATURDAY TO COOL TEMPS BACK DOWN A FEW DEGREES. THE PUSH WILL ENHANCE SHOWER ACTIVITY YET AGAIN AGAINST THE FOOTHILLS...PUT MOISTURE IS EXPECTED TO BE LESS WITH THIS SYSTEM. SUNDAY AND INTO THE FIRST HALF OF NEXT WEEK WILL FEATURE A WARMING AND DRYING TREND AS MODERATE TO STRONG UPPER RIDGING MOVES IN FROM THE WEST. TEMPERATURES WILL LIKELY REACH AND GO ABOVE NORMAL READINGS...WITH THE PLAINS HAVING READINGS IN THE 70S AND LOW 80S WHILE THE MOUNTAINS ENJOY READINGS IN THE 50S TO 60S. AVIATION...CLOUDS WILL INCREASE AND CEILINGS LOWERING DURING THE MORNING HOURS WITH ILS CONDITIONS PROBABLE BY LATE AM OR EARLY AFTERNOON. ENOUGH INSTABILITY FOR EMBEDDED THUNDERSTORMS THIS AFTERNOON AND EVENING AS WELL. CURRENT LOCAL TERMINALS LOOK REASONABLE AND EXPECT ONLY SOME MINOR TWEAKS WITH TIMING AND CEILING HEIGHTS. SURFACE WINDS WILL BE SHIFTING NORTHEAST BY AFTERNOON. THERE WILL BE SOME ERRATIC AND GUSTY WINDS WITH SHOWERS AND STORMS SO SPEEDS COULD JUMP TO 25KT IN THE STRONGER STORMS. HYDROLOGY...RAIN SHOWERS AND EMBEDDED THUNDERSTORMS WILL BE ON THE INCREASE BY AFTERNOON WITH SOME CONCERN FOR POTENTIAL FOR HEAVY RAIN GIVEN INCREASING MOISTURE LEVELS AND SLOW STORM MOTIONS. OVERALL THREAT SEEMS MORE LOCALIZED BUT BURN AREAS WILL NEED TO BE WATCHED CLOSELY. BASED ON LAST NIGHT`S ACTIVITY COULD SEE A AN INCH OF RAIN IN LESS THAN AN HOUR WITH THE STRONGER STORMS TODAY. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR COZ034. && $$ SHORT TERM...D-L LONG TERM....KRIEDERMAN AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1219 PM CDT WED MAY 8 2013 ...AVIATION UPDATE... .UPDATE... ISSUED AT 1042 AM CDT WED MAY 8 2013 THE FORECAST REMAINS A BIT TRICKY REGARDING MESOSCALE FEATURES AS WEAKENING AREA OF PRECIP AND ASSOCIATED WEAK MCV OVER SOUTHEAST KANSAS HAS INTERFERED WITH THE BROAD SCALE SURFACE PATTERN. SURFACE LOW PRESSURE REMAINS CENTERED OVER THE OKLAHOMA PANHANDLE WITH SOME SEMBLANCE OF A SURFACE TROUGH EXTENDING NORTHEAST THROUGH CENTRAL KANSAS AND INTO EXTREME NORTHEAST KANSAS. THESE FEATURES ARE NOT EXPECTED TO MOVE MUCH THROUGH THE DAY TODAY. SOUTHERLY FLOW HAS RESUMED INTO CENTRAL KANSAS IN THE WAKE OF THE PRECIPITATION BUT SOUTHEASTERLY LOW LEVEL FLOW PERSISTS OVER SOUTHEAST KANSAS BEHIND A WEAK OUTFLOW BOUNDARY OF SORTS. THIS COLD POOL AIRMASS IS EXPECTED TO MIX OUT WITH SOUTHERLY FLOW RESUMING BY EARLY AFTERNOON BUT WEAK REMNANT BOUNDARIES MAY PROVIDE JUST ENOUGH FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT BY MID TO LATE AFTERNOON. DRIER MID LEVEL AIR WITH STEEPENING LAPSE RATES IS ALSO FORECAST TO MOVE NORTHEAST INTO THE FORECAST AREA BY THIS AFTERNOON AND SHOULD CONTRIBUTE TO SURFACE BASED INSTABILITY TO AROUND 2000 J/KG WITH MINIMAL INHIBITION. WEAK CONVERGENCE ALONG THE SURFACE TROUGH AXIS AND ANY WEAK REMNANT BOUNDARIES WILL LIKELY BE SUFFICIENT TO OVERCOME THE WEAK INHIBITION LATE THIS AFTERNOON AND THIS EVENING BUT THE EXTENT OF THUNDERSTORM COVERAGE REMAINS IN QUESTION THROUGH THIS PERIOD. DEEP LAYER SHEAR PROFILES ARE EXPECTED TO BE RATHER WEAK...PERHAPS SUPPORTING BRIEF SUPERCELL STRUCTURES BUT MORE LIKELY IN THE MULTICELL REALM OF CONVECTION. AT THIS TIME...IT APPEARS THAT THE STRONGEST STORMS MAY BE CAPABLE OF PRODUCING ISOLATED AND MARGINALLY SEVERE HAIL AND DOWNBURST WINDS. LATE THIS EVENING AND OVERNIGHT...IT APPEARS THAT CONVECTION OVER THE HIGH PLAINS WILL MERGE INTO AN MCS OF SORTS WHICH SHOULD RIDE ALONG THE SURFACE TROUGH AXIS AND NORTH EDGE OF THE INSTABILITY AXIS ACROSS KANSAS...WITH INCREASING CHANCES FOR THUNDERSTORMS AFTER MIDNIGHT. STRONG WINDS ARE NOT OUT OF THE QUESTION WITH THIS ACTIVITY...BUT FEEL THAT THE INSTABILITY WILL BE WANING BY THE TIME STORMS REACH EASTERN KANSAS AND MAY NO LONGER SUPPORT A SEVERE WEATHER THREAT. BARJENBRUCH && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 356 AM CDT WED MAY 8 2013 08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB. FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS. LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND POSSIBLY SOME DAMAGING WIND GUSTS. WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3 AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH. SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON THE WARM SIDE OF THE TROUGH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 356 AM CDT WED MAY 8 2013 ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY. A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN THE LOW TO MIDDLE 80S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1211 PM CDT WED MAY 8 2013 EXPECT PREDOMINANT VFR CONDITIONS THROUGH THE TAF PERIOD WITH MAIN UNCERTAINTY BEING THE TIMING OF THUNDERSTORMS AND ANY POTENTIAL REDUCTION IN FLIGHT CONDITIONS WITH TS. EXPECT TS TO WAIT UNTIL AFTER 22Z BEFORE SCATTERED STORMS INITIATE...AND MAY WAIT UNTIL AFTER 00Z. TS CHANCES INCREASE THIS EVENING AND OVERNIGHT WITH MULTIPLE ROUNDS OF TS POSSIBLY IMPACTING TAF SITES. VIS MAY BRIEFLY REDUCE TO IFR UNDER HEAVIER STORMS BUT TIMING VERY UNCERTAIN. BETTER CHANCE OF MORE PERSISTENT MVFR CIGS AS PRECIP WINDS DOWN AFTER 09Z OR SO...BUT FEEL MORE CONFIDENT IN VFR AT THIS TIME. BARJENBRUCH && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARJENBRUCH SHORT TERM...WOLTERS LONG TERM...63 AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS PADUCAH KY
300 PM CDT WED MAY 8 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 300 PM CDT WED MAY 8 2013 THE LATEST AVAILABLE HRRR OUTPUT DEVELOPS AT LEAST SCATTERED CONVECTION AHEAD OF THE MCV MOVING OVER CENTRAL MISSOURI. STARTING TO SEE SOME ENHANCEMENT ON VISIBILTY SATELLITE IMAGERY AND SOME SHOWER DEVELOPMENT TO OUR WEST/NORTHWEST ON RADAR. DECIDED TO INCREASE POPS UP TO LOWER CHANCE LEVELS COMING OUT OF THE OZARK FOOTHILLS THROUGH SUNSET. THE HRRR DISSIPATES THE STRONGER ELEMENTS AS THEY APROACH THE MISSISSIPPI RIVER AROUND 02Z. FOLLOWED THE HRRR CLOSELY INTO THE EVENING...AND WILL HAVE A DRY FORECAST BY 03Z. ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTHWEST INDIANA AND THE PENNYRILE THIS AFTERNOON SHOULD DISSIPATE OR MOVE SOUTH/EAST OF THE AREA BY SUNSET. THE 12Z MODELS ARE TRENDING DRIER FOR LATER TONIGHT AND ESPECIALLY THURSDAY. SOUNDINGS INDICATE THAT A WEAK CAP WILL BE SUFFICIENT TO KEEP MOST AREAS DRY...DUE TO A GENERAL LACK OF DEEP MOISTURE OR MAJOR FORCING. WILL SPREAD GOOD CHANCE POPS EASTWARD ALONG THE I-64 CORRIDOR THROUGH THE MORNING AND KEEP THEM AT THAT LEVEL THERE THROUGH THE AFTERNOON AND INTO THE EVENING. THIS AREA WILL BE CLOSEST TO ANY EFFECTS OF MID/UPPER LEVEL DISTURBANCES AND THE FRONT ITSELF. WOULD BE VERY SURPRISED TO SEE ANYTHING MORE THAN A VERY ISOLATED STORM PULSE UP TO NEAR SEVERE LEVELS ALONG I-64 THURSDAY AFTERNOON. WILL KEEP SLIGHT CHANCES TO THE SOUTH JUST IN CASE WE DESTABILIZE ENOUGH FOR A PARCEL TO BREAK THROUGH DURING THE AFTERNOON. THURSDAY WILL SEE INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS...AS THE COLD FRONT AND IMPACTS OF THE PRIMARY MID/UPPER LEVEL DISTURBANCE APPROACH THE AREA. THE LLJ WILL INCREASE TO AROUND 35KTS...WHICH SHOULD HELP TO BRING SOME BETTER...DEEPER MOISTURE NORTHEAST ACROSS MUCH OF THE AREA. WILL HAVE A SOUTHWEST TO NORTHEAST BAND OF LIKELY POPS OVER SOUTHEAST MISSOURI AND SOUTHERN ILLINOIS LATE IN THE EVENING...AND THEN MOVE IT SLOWLY EASTWARD ACROSS THE REMAINDER OF THE AREA OVERNIGHT. THE MODELS SEEM TO HAVE CONVERGED FOR FRIDAY. A WEAK COLD FRONT WILL SLOWLY PUSH EASTWARD ACROSS THE AREA THROUGH THE DAY AND SHOULD CLEAR THE ENTIRE AREA BY EARLY EVENING. WITH THE FRONT AND THE MAIN MID/UPPER DISTURBANCE OVER THE AREA FRIDAY...LIKELY POPS SEEM WARRANTED...WITH AN EMPHASIS OVER WEST KENTUCKY. A LACK OF FORCING...ONLY WEAK INSTABILITY...AND GENERALLY WEAK WIND PROFILES SHOULD KEEP ANY CONVECTION WELL BELOW SEVERE LIMITS. SOME VERY LOCALIZED HEAVY RAINFALL SHOULD BE THE PRIMARY CONCERN FRIDAY. POPS WILL LINGER INTO FRIDAY EVENING...MAINLY IN THE EAST...BUT THE MODEL CONSENSUS IS FOR THE ENTIRE AREA TO BE DRY BY 06Z SATURDAY. AS FOR TEMPERATURES...WENT ON HIGH END OF GUIDANCE FOR HIGHS THURSDAY...AND TOWARD THE COOL SIDE FRIDAY. WENT A BIT ABOVE GUIDANCE FOR LOWS FRIDAY NIGHT. OTHERWISE...CONSENSUS OF GUIDANCE SHOULD BE FINE. .LONG TERM...(SATURDAY THROUGH WEDNESDAY) ISSUED AT 300 PM CDT WED MAY 8 2013 OVER THE WEEKEND...A CLOSED LOW OVER ONTARIO AT THE START OF THE PERIOD...MOVES EAST AND ENDS UP CARVING A DEEP TROUGH OVER THE GREAT LAKES AND DOWN INTO OUR REGION. A SECONDARY FRONT MOVES SOUTH TOWARD US ON SATURDAY AND WHILE IT SEEMS TO START OUT WITH ENOUGH MOISTURE TO OUR NORTH...BY THE TIME THE FRONT GETS HERE SATURDAY EVENING...NOT MUCH MOISTURE IS LEFT. SO OPTED TO REMOVE ALL POPS FOR SATURDAY. BEHIND THE SECONDARY COLD FRONT...MUCH COOLER AIR WILL FILTER INTO THE AREA SATURDAY NIGHT AND INTO SUNDAY...ON THE NOSE OF SFC HIGH PRESSURE FROM CANADA. THE 00Z/12Z ECMWF AND 06Z/12Z GFS INDICATE 850MB TEMPS AT OR BELOW ZERO IN OUR FAR NORTHERN COUNTIES. HOWEVER...SINCE HIGH PRESSURE WILL STILL BE MOVING IN...THE WIND WILL LIKELY STAY UP WHICH WILL PREVENT US FROM DROPPING TOO LOW ON OUR LOW TEMPS FOR SATURDAY NIGHT. THE SFC HIGH WILL FINALLY BEGIN TO SETTLE OVER THE AREA ON SUNDAY AND SUNDAY NIGHT...WITH ALL INDICATIONS THAT THE CENTER OF THE HIGH WILL BE DIRECTLY OVER US ON 12Z MONDAY. WITH COLD AIR ADVECTION IN FULL SWING ON SUNDAY...WOULD VENTURE TO GUESS WE WILL NOT GET OUT OF THE 60S FOR HIGHS. THE COLDEST AIR WILL BE SITUATED OVER OUR NORTHEASTERN COUNTIES (NAMELY SE IL...SWIN...PENNYRILE). LOOKING AT CIPS ANALOG DATA ALONG WITH RECORDS FROM XMACIS...WE COULD BE LOOKING AT LOWS SUNDAY NIGHT FALLING INTO THE UPPER 30S FOR THESE PORTIONS OF OUR AREA IF THE GFS IS CORRECT. 850 MB TEMPS OFF THE GFS AND THE GFS ENSEMBLE MEAN ARE A BIT COOLER THAN THE ECMWF...AND WITH CALM WINDS AND CLEAR SKIES...WE COULD DROP QUITE A BIT. LOOKING AT RAW MODEL DEWPOINT TEMPS...THIS ALSO SUPPORTS THESE COOLER TEMPS...WHICH COULD GET CLOSE TO TYING RECORDS IN THE EVV AREA. ELSEWHERE THOUGH...IT STILL LOOKS COOL WITH LOWS IN THE LOWER 40S. AGAIN...THIS MAY BE COLD ENOUGH TO SUPPORT THE FORMATION OF VERY PATCHY FROST IN OUTLYING AREAS...BUT A WIDESPREAD FROST IS STILL NOT ANTICIPATED ATTM. THE SFC HIGH MOVES EAST AND EVENTUALLY SOUTH ON MONDAY/MONDAY NIGHT AND THAT IS WHEN THE WARM UP WILL BEGIN. DEPENDING ON HOW LOW WE START THE DAY WITH ON MONDAY...WE WILL STILL BE COOL WITH HIGHS REMAINING IN THE 60S/POSSIBLY AROUND 70 FAR WEST. THE FLOW IN THE LOW LEVELS BECOMES SOUTHERLY/SOUTHWESTERLY LATE MONDAY NIGHT INTO TUESDAY AND 850 MB TEMPS WILL RISE STEADILY FROM THEN THROUGH THE END OF THE EXTENDED PERIOD (WEDNESDAY). THEREFORE...WE EXPECT HIGHS IN THE 70S ON TUESDAY WITH AROUND 80 ON WEDNESDAY. THIS EARLY WEEK PERIOD CONTINUES TO BE DRY. LOOKING BEYOND THAT...MODELS TRY TO BRING A FRONT INTO THE AREA BUT DIFFER ON TIMING. && .AVIATION... ISSUED AT 1231 PM CDT WED MAY 8 2013 A STRAY SHOWER MAY FLIRT WITH KEVV AND KOWB THIS AFTERNOON...BUT CONFIDENCE IS TOO LOW AT THIS TIME TO INCLUDE EVEN A VCSH. WILL MONITOR RADAR/SATELLITE TRENDS AND ADD IN SHRA/TSRA AS NEEDED THIS AFTERNOON. DO NOT FEEL THAT ANY ACTIVITY OVER SOUTHEAST MISSOURI THIS AFTERNOON WILL IMPACT KCGI...SO KEPT IT DRY AS WELL. GUIDANCE INDICATES THAT MID-LEVEL CEILINGS WILL OVERSPREAD THE AREA FROM WEST TO EAST TONIGHT. A LIGHT SOUTH WIND IS EXPECTED TO DEVELOP IN THE WEST TONIGHT...BUT WINDS WILL LIKELY BE CALM IN THE EAST. CONSIDERED ADDING FOG OVERNIGHT IN THE EAST...BUT DECIDED AGAINST IT...AS MID CLOUDS SHOULD BE ON THE INCREASE OVERNIGHT RIGHT WHEN THE FOG WOULD OTHERWISE BE DEVELOPING. FEEL THAT ANY CONVECTION LATE TONIGHT OR THURSDAY WILL REMAIN TO THE NORTH AND WEST OF THE TAF SITES. WILL SEE SOME CU UNDER A CEILING AOA 15KFT THURSDAY MORNING. WINDS WILL BE INCREASING FROM THE SOUTH...ESPECIALLY AT KCGI AND KPAH...WHERE GUSTS WELL OVER 20KTS WILL BE POSSIBLE. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...DRS LONG TERM...CW AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1231 PM CDT WED MAY 8 2013 .UPDATE... ISSUED AT 1231 PM CDT WED MAY 8 2013 THE PUBLIC FORECAST WAS UPDATED EARLIER THIS MORNING. TEMPERATURES GOT OFF TO A FAST START...AND THE RUC TEMPERATURES INDICATE HIGHS AROUND 80 THROUGHOUT THE AREA. ALSO...THE NAM AND HRRR DEVELOP SOME SHOWERS AND POSSIBLY THUNDERSTORMS OVER SOUTHEAST MISSOURI. THIS CONVECTION WOULD BE A COMBINATION OF WARMER THAN EXPECTED TEMPERATURES AND A DISTURBANCE MOVING ACROSS CENTRAL MISSOURI THROUGH THE AFTERNOON. ALL INDICATIONS ARE THAT THIS ACTIVITY WILL BE DIURNAL IN NATURE...THEREFORE WOULD NOT EXPECT MUCH IF ANY ACTIVITY LEFT AFTER 00Z. A SLIGHT CHANCE OF SHOWERS AND STORMS REMAINS IN THE FORECAST FOR THE EASTERN THIRD OF THE AREA THIS AFTERNOON. THE AVIATION SECTION HAS BEEN UPDATED FOR THE 18Z TAF ISSUANCE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 252 AM CDT WED MAY 8 2013 WILL CONTINUE WITH SLIGHT CHANCE POPS ACROSS THE PENNYRILE REGION TODAY AND A LIMITED CHANCE IN THE OZARK FOOTHILL REGION. OTHERWISE MAINLY DRY MOST AREAS WITH HIGHS A LITTLE WARMER THAN YESTERDAY. SHOULD BE MAINLY DRY TONIGHT. MODELS SLOWER THEN PREVIOUS TWO DAYS BRINGING CHANCE OF CONVECTION INTO THE REGION. THEREFORE WILL HOLD OFF POPS TIL THURSDAY AND RAMP THEM UP THURSDAY NIGHT INTO FRIDAY AS A FRONT MOVES TOWARD AND THEN THROUGH THE AREA. AM NOT CONCERNED WITH SEVERE WEATHER AT THIS TIME. A STRONG STORM OR TWO CANNOT BE RULED OUT. CHANCES SHOULD GRADUALLY LOWER FROM NORTHWEST TO SOUTHEAST FRIDAY NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 252 AM CDT WED MAY 8 2013 MOST OF THE PRECIPITATION WITH THE FIRST COLD FRONT SHOULD BE EAST OF THE REGION BY 12Z SATURDAY. HOWEVER...THE MOST NOTICEABLE CHANGE IN AIR MASS WILL NOT OCCUR UNTIL A SECONDARY COLD FRONT PASSES ACROSS THE REGION SATURDAY AFTERNOON AND EVENING. WHILE ALL MODELS CONTINUE TO INDICATE A DRY FRONTAL PASSAGE...THEY DO DEVELOP SPOTTY PRECIPITATION JUST NORTH OF THE REGION AS THE FRONT APPROACHES SATURDAY AFTERNOON. FOR THIS REASON...WILL MAINTAIN GOING SLIGHT CHANCE MENTION OF THUNDER DURING THE DAYLIGHT HOURS SATURDAY. ONCE THE FRONT PASSES THROUGH...A TRANSITION TO DRY AND UNSEASONABLY COOL WEATHER IS EXPECTED ON SUNDAY. HIGHS IN THE LOWER 60S WILL BE ABOUT 15 DEGREES BELOW NORMAL. SUNDAY NIGHT LOOKS LIKE THE COLDEST NIGHT WITH LOWS NEAR THE 40 DEGREE MARK. THIS MAY BE COLD ENOUGH TO SUPPORT THE FORMATION OF VERY PATCHY FROST IN OUTLYING AREAS...BUT A WIDESPREAD FROST IS NOT ANTICIPATED. A WARMING TREND WILL TAKE PLACE DURING THE FIRST HALF OF NEXT WEEK AS AN UPPER LEVEL RIDGE BUILDS EAST FROM THE PLAINS AND SOUTHERLY FLOW DEVELOPS ON THE BACK SIDE OF THE DEPARTING SURFACE HIGH. HIGHS WILL MODERATE FROM THE UPPER 60S ON MONDAY INTO THE MID 70S BY TUESDAY. WEDNESDAY LOOKS EVEN WARMER AS TEMPERATURES NEAR THE 80 DEGREE MARK. && .AVIATION... ISSUED AT 1231 PM CDT WED MAY 8 2013 A STRAY SHOWER MAY FLIRT WITH KEVV AND KOWB THIS AFTERNOON...BUT CONFIDENCE IS TOO LOW AT THIS TIME TO INCLUDE EVEN A VCSH. WILL MONITOR RADAR/SATELLITE TRENDS AND ADD IN SHRA/TSRA AS NEEDED THIS AFTERNOON. DO NOT FEEL THAT ANY ACTIVITY OVER SOUTHEAST MISSOURI THIS AFTERNOON WILL IMPACT KCGI...SO KEPT IT DRY AS WELL. GUIDANCE INDICATES THAT MID-LEVEL CEILINGS WILL OVERSPREAD THE AREA FROM WEST TO EAST TONIGHT. A LIGHT SOUTH WIND IS EXPECTED TO DEVELOP IN THE WEST TONIGHT...BUT WINDS WILL LIKELY BE CALM IN THE EAST. CONSIDERED ADDING FOG OVERNIGHT IN THE EAST...BUT DECIDED AGAINST IT...AS MID CLOUDS SHOULD BE ON THE INCREASE OVERNIGHT RIGHT WHEN THE FOG WOULD OTHERWISE BE DEVELOPING. FEEL THAT ANY CONVECTION LATE TONIGHT OR THURSDAY WILL REMAIN TO THE NORTH AND WEST OF THE TAF SITES. WILL SEE SOME CU UNDER A CEILING AOA 15KFT THURSDAY MORNING. WINDS WILL BE INCREASING FROM THE SOUTH...ESPECIALLY AT KCGI AND KPAH...WHERE GUSTS WELL OVER 20KTS WILL BE POSSIBLE. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS AVIATION...DRS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
409 PM EDT WED MAY 8 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 408 PM EDT WED MAY 8 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS STILL SHOW BLOCKY FLOW DOMINATING THE CONUS TO THE S OF PROGRESSIVE BUT GRADUALLY AMPLIFYING FLOW ACROSS CANADA. IN THE BLOCKY CONUS FLOW...MID LEVEL LOWS ARE LOCATED OVER THE SOUTHERN ROCKIES...ERN SD AND THE MID ATLANTIC STATES. TO THE N...FLOW ACROSS CANADA HAS AMPLIFIED SOME IN THE LAST COUPLE OF DAYS AS TROFFING IS NOSING S THRU MANITOBA/NRN ONTARIO. MUCH STRONGER AMPLIFICATION WILL FOLLOW THIS WEEKEND AS SHARP TROFFING DEVELOPS S INTO THE GREAT LAKES. COLD FRONT ASSOCIATED WITH SHORTWAVE THAT MOVED FROM MANITOBA YESTERDAY TO QUEBEC TODAY IS JUST NW AND N OF LAKE SUPERIOR. AHEAD OF THE FRONT...IT HAS BEEN ANOTHER WARM DAY ACROSS UPPER MI. SOME LOCATIONS ALONG LAKE SUPERIOR HAVE EXPERIENCED A MUCH WARMER DAY TODAY AS LAKE BREEZE DID NOT DEVELOP AS EARLY AS IN PREVIOUS DAYS...AND IT IS WEAKER. DESPITE ONSHORE WINDS ALONG LAKE MI...COOLING THERE HAS ONCE AGAIN BEEN WEAK. INLAND...TEMPS HAVE SOARED THRU THE 70S WITH A FEW SPOTS REACHING 80F. VERY DRY AIR STILL LINGERS OVER A GOOD PORTION OF UPPER MI (NOTE THE VERY DRY COLUMN AGAIN SAMPLED BY THE 12Z KGRB SOUNDING). AS A RESULT...DWPTS HAVE CRASHED DOWN AS LOW AS THE UPPER 20S/LWR 30S ACROSS PORTIONS OF MAINLY CNTRL/ERN UPPER MI. RH IS IN THE 15-25PCT RANGE AT MOST LOCATIONS. FORTUNATELY...WINDS REMAIN LIGHT...KEEPING FIRE WX CONCERNS IN CHECK FROM WHERE THEY COULD BE ON A DAY LIKE THIS. SOME OF THE MID LEVEL MOISTURE NOTED ON PREVIOUS DAYS SOUNDINGS FROM KINL/KMPX HAS ADVECTED INTO UPPER MI TODAY AND MADE ITS PRESENCE KNOWN WITH POCKETS OF SCT/BKN MID CLOUDS EARLIER IN THE DAY. DAYTIME HEATING HAS NOW LED TO VERY HIGH BASED CU DEVELOPING OVER MUCH OF UPPER MI. A FEW RADAR RETURNS HAVE APPEARED ON KMQT RADAR IMAGERY OVER WRN UPPER MI...BUT DRY LOW-LEVEL AIR HAS PROBABLY PREVENTED ANY PCPN OR AT LEAST NOTHING MORE THAN A FEW SPRINKLES FROM REACHING THE GROUND. COLD FRONT TO THE N WILL DROP S...PASSING ACROSS UPPER MI TONIGHT/EARLY THU MORNING. LOW-LEVEL DRY AIR WILL CONTINUE TO BE A PROBLEM DUE TO LITTLE ADVECTION OF ANY MOISTURE AT THE LOW-LEVELS. EVEN UPSTREAM...KINL/KMPX SOUNDINGS SHOW THAT LOW-LEVELS THERE HAVE BEEN DRYING OUT OVER THE LAST DAY OR TWO...BUT THERE IS STILL SUFFICIENT MOISTURE FOR SCT SHRA AND EVEN A FEW TSRA OVER NRN MN INTO NW WI THIS AFTN. AS MID LEVEL LOW OVER ERN SD DRIFTS E...IT MAY HELP PUSH BETTER MOISTURE INTO THE FRONTAL BOUNDARY THAT IS DROPPING OVER THE AREA. HOWEVER...GIVEN THE LOW-LEVEL WIND FLOW/LACK OF MOISTURE ADVECTION...PREFER THE GEM/ECMWF/UKMET AND TO SOME DEGREE THE NAM IDEA OF MAINTAINING THE LOW-LEVEL DRY AIR OVER THE AREA TONIGHT. AS A RESULT...WILL ONLY INCLUDE SCHC/LOW CHC POPS OVER THE NW PORTION OF THE FCST AREA. WITH MID LEVEL LOW OPENING UP/WEAKENING AS IT TRACKS E THU...IT PROBABLY WON`T BE ABLE TO BRING A GOOD PUSH OF MOISTURE N OF THE COLD FRONT THAT PASSED THRU THE AREA. HOWEVER...THERE ARE INDICATIONS THAT MID LEVEL FGEN WILL INCREASE ACROSS THE UPPER LAKES. WITH COLD FRONT SLIPPING S OF THE FCST AREA IN THE MORNING...THERE WILL BE A BETTER OPPORTUNITY FOR LOW-LEVELS TO MOISTEN IN THE COOLER AIR MASS UNDERNEATH THE FGEN FORCING...AND THIS SHOULD PROVIDE AT LEAST A CHANCE OF SHRA OVER MUCH OF THE AREA THU. WILL PAINT MAINLY THE WRN FCST AREA FOR BEST CHC OF SHRA AS THERE ARE HINTS OF LOW-LEVEL DRY AIR STILL LINGERING OVER THE E. WITH CAA AND MORE CLOUDS...IT WILL BE A COOLER DAY...ESPECIALLY NEAR LAKE SUPERIOR DUE TO GRADIENT FLOW ACROSS THE LAKE (TEMPS ALONG THE LAKE WILL PROBABLY ONLY BE IN THE LOW/MID 40S THRU THE DAY). ACROSS THE SCNTRL AND E...TEMPS MAY STILL REACH THE MID 60S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 408 PM EDT WED MAY 8 2013 UPPER FLOW GOES THROUGH A TRANSITION DURING THE LONG TERM PERIOD. INITIALLY ON THURSDAY NIGHT FLOW IS MORE ZONAL WITH BROAD SHALLOW TROUGH OVER MOST OF CANADA. LATER FRIDAY TRHOUGH SATURDAY...EXPECT SHARP AMPLIFICATION AS TROUGH CURRENTLY NORTH OF ALASKA BARRELS ACROSS CANADIAN PRAIRIES AND ONTARIO. PRIMARY COLD FRONT SWINGS ACROSS UPPER MICHIGAN FRIDAY NIGHT INTO SATURDAY MORNING WITH PARENT SFC LOW REACHING CENTRAL QUEBEC BY SUNDAY MORNING. MODELS HAVE TRENDED FARTHER EAST WITH UPPER LOW CENTER AND QUICKER WITH FRONTAL PASSAGE. TROUGH ALOFT SLOWLY MOVES INTO EASTERN CANADA ON MONDAY WITH STRONG RIDGE AND WARM AIR EXPANDING TOWARD CENTRAL CANADA AND THE PLAINS. TAIL END OF EXTENDED FEATURES WARMING TREND OVER UPPER LAKES AS RIDGING MOVES FARTHER EAST. MAY SEE BREEZY CONDITIONS ACCOMPANYING THE WARM UP AS STRONG LOW PRESSURE MOVES FROM MANITOBA TO NORTHWEST ONTARIO. SHALLOW COOL AIR SLOWLY FILTERS ACROSS UPR MICHIGAN LATER THURSDAY AND THURSDAY EVENING. STILL A POTENTIAL OF RAIN THURSDAY EVENING WITH LINGERING H7-H5 MOISTURE/LIFT DUE TO H7-H6 FRONTOGENESIS. NAM AND GFS MORE BULLISH ON QPF OVER CWA COMPARED TO ECMWF AND GEM-NH. THINKING NAM IDEA IS TOO FAR WEST WITH PRECIPITATION BAND...BUT WILL KEEP SMALL POPS OVER SOUTH AND EAST THROUGH 03Z FRIDAY. REST OF THURSDAY NIGHT INTO FRIDAY LOOKING QUIET OUT AHEAD OF THE STRONG COLD FRONT. ONE CONCERN COULD BE STRONGER EAST-NORTHEAST WINDS OVER EASTERN CWA THURSDAY NIGHT INTO FRIDAY MORNING...ESPECIALLY IF NOT MUCH RAIN OCCURS THERE AND HUMIDITY RECOVERIES ARE POOR THURSDAY NIGHT. GRADIENT WINDS DIMINISH THROUGH THE DAY ON FRIDAY...BUT AS BUBBLE HIGH AT 1025MB BUILDS OVER LK SUPERIOR...NORTH WINDS COULD STAY GUSTY INTO MID AFTN FROM COPPER HARBOR TO MARQUETTE AND GRAND MARAIS. VERY DRY CONDITIONS AS H85 DWPNTS ARE DOWN TO AROUND -30C. GIVEN SUCH DRY AIRMASS...EXPECT MIXED LAYER DWPNTS TO MIX OUT AWAY FROM IMMEDIATE LK SUPERIOR SHORE AS LOW AS MID-UPPER TEENS IN THE AFTN. EVEN WITH MUCH COOLER TEMPERATURES...ONLY AS WARM AS THE UPPER 50S INLAND...LOW DWPNTS WILL RESULT IN HUMIDITY VALUES BLO 25 PCT IN AFTERNOON. BASED ON SOUNDINGS...DRY AIRMASS HANGS ON THROUGH FRIDAY EVENING OVER ALL CWA. FOCUS THEN IS ON STRONG COLD FRONTAL PASSAGE BY SATURDAY. 1000-500MB THICKNESS PACKING FROM ECMWF/GFS/NAM INDICATE FRONTAL PASSAGE AFTER MIDNIGHT FRIDAY NIGHT OVER FAR WEST CWA AND EARLY SATURDAY AFTERNOON OVER THE FAR EASTERN CWA. SOUNDINGS SHOW MOISTURE BUILDING DOWN FROM MID-LEVELS...RESULTING IN ONLY A FEW HOURS OF SATURATION FOR SOME SHOWERS BEFORE DRYING AND SUBSIDENCE KICK IN BEFORE DAYBREAK OVER WESTERN CWA AND BY MID MORNING OVER EASTERN CWA. WITH THE INITIAL BATCH OF SHOWERS...LOOKS LIKE IT REMAINS TOO WARM BLO H9 TO HAVE SNOW MIX IN WITH THE RAIN. 06Z NAM SHOWED ENOUGH COLD AIR WORKING IN JUST AS PRECIP ENDED AT ERY FOR SOME SNOW SATURDAY MORNING. 12Z RUN KEEPS IT ALL LIQUID. UNCERTAIN HOW MUCH MOISTURE IS AROUND ON SATURDAY...BUT THAT WILL HAVE BEARING ON HOW MUCH PRECIP OCCURS AND WHETHER THERE WILL BE ANY SNOW OR MIXED RAIN AND SNOW. THINKING THAT NAM MAY BE OVERDONE WITH EXTENT OF SUBSIDENCE/DRYING OR AT THE LEAST THE EXTENT/DURATION OF DRYING ON SATURDAY. GFS/ECMWF POINT TO CHANCE OF MORE DIURNAL/COLD POOL TYPE SHOWERS AS TOTAL TOTALS PUSH 50 AND WITH INCREASING H85-H7 RH. SHOULD SEE LOTS OF CLOUDS AND WILL GO WITH LOW CHANCES FOR SHOWERS MOST AREAS. GIVEN ENOUGH MOISTURE AS GFS/ECMWF INDICATE...WET BULB BLO ZERO THROUGH THE DEPTH OF THE COLUMN WOULD SUPPORT AT LEAST A MIX OF RAIN AND SNOW OVER THE WEST HALF. MAX TEMPS IN UPPER 30S TO LOWER 40S AT THE COOLEST WILL NOT ALLOW FOR ANY APPRECIABLE SNOW ACCUMS THOUGH THERE COULD BE BRIEF REDUCED VSBY IN THE HEAVIEST SNOW SHOWERS. OTHER ISSUE ON SATURDAY WILL BE STRONG/GUSTY WINDS. SOUNDINGS INDICATE UNIDIRECTIONAL WNW 30-40 KT MIXED LAYER WINDS. PORTION OF THESE WINDS WILL MIX DOWN IN GUSTS DUE TO MECHANICAL MIXING AND COLD AIR ADVECTION. EXPECT STRONGEST WINDS OVER 40 MPH ON THE KEWEENAW PENINSULA...WITH GUSTS OVER 30 MPH ELSEWHERE. DRYING TREND TAKES OVER SUNDAY INTO MONDAY AS THE LARGER SCALE TROUGH DEPARTS THE AREA. STILL COOL FOR SUNDAY WITH SIMILAR READINGS TO SATURDAY. QUITE CHILLY SUNDAY NIGHT WITH MANY AREAS FALLING BLO FREEZING WITH PWAT LESS THAN 50 PCT OF NORMAL AS SFC HIGH PRESSURE RIDGE MOVES ACROSS. REST OF EXTENDED FEATURES WARMING TREND AS RIDGE OVER PLAINS BUILDS ACROSS. ELEVATED MOISTURE AND INSTABILITY WITH THE WARM AIR ADVECTION MAY TRIGGER SCT SHOWERS/TSRA TUESDAY. CHANCES FOR WIDESPREAD PRECIP SEEM LOW THOUGH AS PRIMARY LARGE SCALE LIFT STAYS OVER ONTARIO. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 128 PM EDT WED MAY 8 2013 EXPECT VFR CONDITIONS THRU THE EVENING AT KIWD/KCMX/KSAW AS LOW-LEVELS REMAIN VERY DRY. INCREASE IN MID LEVEL MOISTURE MAY YIELD SOME HIGH BASED SHRA IN THE VCNTY OF KIWD THIS AFTN/TONIGHT AND AT KCMX LATER TONIGHT. LATE TONIGHT INTO THU MORNING...STENGTHENING CHILLY N/NE FLOW AND INCREASING POTENTIAL OF -SHRA MAY RESULT IN A LOW STRATOCU/STRATUS DECK DEVELOPING AT KIWD/KCMX. NOT OUT OF THE QUESTION THAT AN IFR CIG COULD DEVELOP AT KIWD WHERE WIND WILL HAVE A BETTER UPSLOPE COMPONENT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 408 PM EDT WED MAY 8 2013 LIGHT WINDS WILL PERSIST INTO THE EVENING. THEN...FOLLOWING THE PASSAGE OF A COLD FRONT TONIGHT...NNE WINDS WILL INCREASE UP TO 15-25KT LATE TONIGHT THRU THU NIGHT. THE ARRIVAL OF ANOTHER HIGH PRES RIDGE WILL THEN CAUSE WINDS TO DIMINISH FRI. A STRONGER COLD FRONT WILL SLIDE ACROSS THE UPPER LAKES FRI NIGHT AND SHIFT WINDS TO THE NW AT 20-30KT FOR SAT. GIVEN TIGHT PRES GRADIENT AND STRENGTH OF CAA...GALE FORCE GUSTS WILL LIKELY OCCUR. WINDS WILL THEN DIMINISH W TO E SUN AS HIGH PRES RIDGE ARRIVES. WINDS SHOULD BE UNDER 15KT LATER SUN NIGHT THRU MON. && .HYDROLOGY... ISSUED AT 408 PM EDT WED MAY 8 2013 WARM TEMPS CONTINUE TO MELT LINGERING SN PACK OVER THE HIER TERRAIN OF THE W AND NCENTRAL. RUNOFF INTO THE MONTREAL RIVER AND ISOLD FLOODING ALONG THE WISCONSIN AND MICHIGAN BORDER IN WESTERN GOGEBIC COUNTY NEAR IRONWOOD PROMPTED EVENING SHIFT ON TUESDAY TO ISSUE AREAL FLOOD ADVISORY FOR GOGEBIC COUNTY. THIS MATCHES UP WITH FLOOD ADVISORY OUT FOR IRON COUNTY WISCONSIN ISSUED BY WFO DULUTH. PLAN TO LET WFO MARQUETTE ADVY EXPIRE AS SCHEDULED AS NO OTHER FLOODING HAS BEEN REPORTED. OTHERWISE...MOST AREA STREAMS/RIVERS CONTINUE TO REMAIN STEADY OR SHOW SLOW DECLINE WITH RECENT DRY WX. WITH MINIMAL PRECIP IN THE FORECAST IN THE COMING DAYS AND BULK OF SNOW PACK GONE EXCEPT OVER THE HIGHER TERRAIN OF THE KEWEENAW/NCENTRAL...SUSPECT THESE TRENDS WILL CONTINUE. RIVER ADVISORIES OR FLOOD WARNINGS CONTINUE FOR THE TRAP ROCK RIVER AT LAKE LINDEN...THE STURGEON RIVER AT ALSTON AND CHASSELL...AND THE MICHIGAMME RIVER AT WITCH LAKE AND REPUBLIC. FOR COMPLETE DETAILS...SEE THE LATEST PRODCUTS FOR THESE RIVER FLOOD WARNINGS AND ADVISORIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...ROLFSON MARINE...ROLFSON HYDROLOGY...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1252 PM CDT WED MAY 8 2013 .UPDATE... ISSUED AT 1252 PM CDT WED MAY 8 2013 MADE MINOR UPDATES TO GRIDS FOR ACTIVITY THAT IS DIMINISHING AS IT GETS CLOSER TO FORECAST AREA. WILL SEE SOME SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON AS DECAYING MCV SLIDES THROUGH REGION...WITH MOST OF ACTIVITY ALONG AND SOUTH OF I-70. STILL EXPECT HIGHS IN THE UPPER 70S TO LOW 80S. BYRD && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 329 AM CDT WED MAY 8 2013 LITTLE CHANGE IN THINKING THIS MORNING SINCE PREVIOUS FORECAST. THE PRIMARY CHALLENGE THIS MORNING IS TIMING THE START OF PRECIP TODAY. IF CURRENT RADAR TRENDS HOLD TRUE...THE SHOWERS CURRENTLY OVER KANSAS WILL REACH THE WESTERN-MOST PORTIONS OF OUR CWFA BETWEEN 16-17Z. THIS TIMING AGREES WELL WITH MOST SHORT RANGE MODEL GUIDANCE INCLUDING THE HRRR AND 4KM NCEP WRF. SHOULD SEE INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTHEAST MISSOURI TONIGHT AS THE COMPACT SHORTWAVE OVER SOUTH DAKOTA DRIFTS SOUTHEAST INTO IOWA. THIS FORCES THE LOW LEVEL JET TO STRENGTHEN OVER THE AREA CAUSING AMPLE LOW LEVEL MOISTURE CONVERGENCE OVER REGION WHICH SHOULD KEEP PRECIPITATION GOING OVER CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS FOR MUCH OF THE NIGHT. THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ACROSS THE REST OF THE AREA ON THURSDAY AS DAYTIME HEATING DESTABILIZES THE ATMOSPHERE AND THE SHORTWAVE CONTINUES TO DIG INTO THE MID-MISSISSIPPI VALLEY. STRONG STORMS ARE POSSIBLE...THO CONDITIONS APPEAR MARGINAL FOR SEVERE WITH 1000-1200 J/KG CAPE BUT ONLY 15-20KTS OF SHEAR. IF THERE ARE SEVERE STORMS WOULD THINK THE PRIMARY THREAT WILL BE DAMAGING WINDS...HAIL THREAT SEEMS LIMITED DUE TO SMALL CAPE VALUES IN THE HAIL GROWTH ZONE. SHOULD SEE PRECIP DECREASE FROM NORTHWEST TO SOUTHEAST LATE THURSDAY NIGHT INTO THE PRE-DAWN HOURS OF FRIDAY MORNING. CANNOT RULE OUT SCATTERED SHOWERS AND THUNDERSTORMS GENERALLY ALONG AND SOUTH OF I-70 AGAIN FRIDAY...BUT THINK THE THREAT FOR ORGANIZED CONVECTION WILL BE MINIMAL. TEMPERATURE TRENDS THROUGH FRIDAY WILL BE HIGHLY DEPENDENT ON PRECIPITATION. GENERALLY STUCK PRETTY CLOSE TO THE MIDDLE OF THE ROAD OF GUIDANCE NUMBERS. CARNEY .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 329 AM CDT WED MAY 8 2013 GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH THE SATURDAY THROUGH MONDAY PERIOD. ANOTHER SHORTWAVE WILL DIG SOUTHEAST OUT OF CANADA INTO THE GREAT LAKES REGION AMPLIFYING THE FLOW ACROSS THE U.S. THIS WILL PUSH A COLD FRONT SOUTH THROUGH THE MISSISSIPPI VALLEY ON SATURDAY. A STRONG CANADIAN HIGH WILL DROP INTO THE ARE BEHIND THE FRONT BRINGING US ANOTHER SHOT OF BELOW NORMAL TEMPERATURES. GFS AND ECMWF CONTINUE TO PRODUCE VERY LIGHT QPF ACROSS PARTS OF THE AREA ON SATURDAY AS THE FRONT MOVES THROUGH SO HAVE KEPT CHANCE POPS IN THE FORECAST. 850MB TEMPS DROP TO NEAR ZERO SUNDAY SO HAVE CONTINUED THE DOWNWARD TREND FOR HIGHS...UNDERCUTTING GUIDANCE BY A FEW DEGREES. MONDAY MORNING WILL LIKELY BE THE COLDEST OF THE BUNCH...WITH POSSIBLY THE LAST FROST OF THE SEASON. SHOULD SEE A NICE WARM UP MONDAY AFTERNOON AND TUESDAY AS AN UPPER LEVEL RIDGE BUILDS OVERHEAD AND SOUTHWEST FLOW RETURNS TO THE AREA. CARNEY && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1252 PM CDT WED MAY 8 2013 SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE CONTINUING TO TRACK TO THE EAST EARLY THIS AFTERNOON. STILL HARD TO SAY IF ACTIVITY WILL HOLD TOGETHER LONG ENOUGH TO AFFECT TAF SITES...SO JUST KEPT VCNTY SHOWER MENTION AT THIS TIME BEFORE TAPERING OFF BY 00Z THURSDAY. OTHERWISE...WINDS TO PERSIST FROM THE SOUTH WITH VFR CIGS THROUGH THE FORECAST PERIOD. BETTER CHANCES OF STORMS WITH MAIN FRONT OVER NORTHEAST MO/WEST CENTRAL IL...SO HAVE TRWS MOVING INTO KUIN BY 07Z THURSDAY. NOT SURE HOW FAR SOUTH THEY WILL GET FOR TAF SITES ALONG I-70 CORRIDOR SO JUST HAVE VCNTY SHOWERS/THUNDERSTORMS FROM MID MORNING ON DURING THE DAY THURSDAY. SPECIFICS FOR KSTL...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE CONTINUING TO TRACK TO THE EAST EARLY THIS AFTERNOON. STILL HARD TO SAY IF ACTIVITY WILL HOLD TOGETHER LONG ENOUGH TO AFFECT METRO AREA...SO JUST KEPT VCNTY SHOWER MENTION BEGINNING AT 22Z WEDNESDAY TAPERING OFF BY 00Z THURSDAY. OTHERWISE...WINDS TO PERSIST FROM THE SOUTH WITH VFR CIGS THROUGH THE FORECAST PERIOD. BETTER CHANCES OF STORMS WITH MAIN FRONT OVER NORTHEAST MO/WEST CENTRAL IL...OVERNIGHT THROUGH THURSDAY. NOT SURE HOW FAR SOUTH THEY WILL GET FOR METRO AREA SO JUST HAVE VCNTY SHOWERS BEGINNING AROUND 13Z THURSDAY AND VCNTY THUNDERSTORMS AFTER 21Z THURSDAY. BYRD && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
258 PM CDT WED MAY 8 2013 .DISCUSSION... PRECIPITATION CHANCES TONIGHT INTO THURSDAY MAIN FORECAST FOCUS IN THE SHORTER TERM. EXTENDED FORECAST WILL DEAL WITH A RELATIVELY BRIEF BUT SUBSTANTIAL COOLDOWN THIS WEEKEND...FOLLOWED BY A MUCH WARMER PATTERN NEXT WEEK. AFTERNOON SATELLITE IMAGERY SHOWED A COMPACT UPPER CIRC CENTER PIVOTING TOWARD NERN NEBR WITH ANOTHER UPPER WAVE MOVG INTO ERN KS. REMNANT SHOWER ACTIVITY ON A LOBE MOVING AROUND SD UPPER LOW WAS MOVG TOWARD FAR ERN ZONES AS OF 19Z...WITH SCATTERED CONVECTION DEVELOPING NEAR THERMAL BOUNDARY BETWEEN PRECIP COOLED AIR AND LOCATIONS WHICH HAD CLEARED UNDER UPPER THERMAL TROUGH IN NERN NEBR. WOULD EXPECTED SCATTERED CONVECTION NERN ZONES INTO AT LEAST EARLY THIS EVENING. ANOTHER AREA WHERE ACTIVITY COULD BE MORE WIDESPREAD...ESPECIALLY EARLY THIS EVENING...WOULD APPEAR TO BE NEAR WARM FRONT WHICH HAD LIFTED INTO FAR SRN NEBR. IN FACT EVEN IF CURRENT ACTIVITY DVLPG NEAR SRN NEBR BOUNDARY DECREASES EARLY THIS EVENING...WE COULD SEE ADDITIONAL DEVELOPMENT LATE THIS EVENING AS SUGGESTED BY THE HRRR AND 4KM WRF AS LOW LEVEL JET STRENGTHENS SOUTH OF BOUNDARY. THE LATTER MODEL EVEN SUGGESTED NERN NEBR ACTIVITY WOULD BEGIN TURNING SE LATER THIS EVENING MEETING UP WITH ANY CONVECTION THAT WOULD INCREASE IN SERN NEBR LATE THIS EVENING. GENERALLY INCREASED POPS MOST AREAS EARLY TONIGHT AND LATEST TRENDS WILL CONTINUE TO BE MONITORED FOR LAST MINUTE CHANGES TO 00Z-03Z PD. AS UPPER LOW OVR SD BEGINS OPENING UP/DROPPING SE LATE TONIGHT...SOME LIGHT SHOWERS COULD MOVE BACK INTO NERN NEBR TOWARD THU MORNING WITH A CONTINUED SOUTHWARD PUSH OF THESE GENERALLY LIGHT SHOWERS THURSDAY MORNING. IN ADDITION...HEATING AND UPPER LOW REMNANTS ON THURSDAY COULD BRING SCATTERED SHOWERS/TSTMS JUST ABOUT ANYWHERE THURSDAY AFTN AND SOME POPS WERE ADDED ALL ZONES. GFS/NAM LINGERED QUITE A BIT OF LOW LEVEL MOISTURE ACROSS MUCH OF THE FORECAST AREA ON THURSDAY WHICH COULD LIMIT THIS HEATING AND COULD PROVIDE A PSBL NEGATIVE. FOR NOW FORECAST WAS KEPT DRY THURSDAY NIGHT ALTHOUGH COULD SEE A LINGERING LIGHT SHOWER/ISOLD TSTM EARLY. CLEARING THEN EXPECTED FRIDAY WITH RELATIVELY LIGHT WINDS AND SEASONAL OR SLIGHTLY COOLER TEMPERATURES. A STRONG COLD FRONT STILL ON TRACK TO RACE ACROSS THE AREA FRIDAY NIGHT WITH GUSTY WINDS AND COOLER READINGS ON SATURDAY. MAINTAINED SMALL POPS WITH FRONTS PASSAGE NRN ZONES FRI NIGHT BUT CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ANY CHCS FARTHER SOUTH. GUSTY NRLY WINDS LIKELY SATURDAY AS SUB-ZERO H85 AIR MOVES INTO NRN ZONES EARLY IN THE DAY BEFORE MODERATING. AIRMASS IS COOL/DRY ENOUGH SO THAT WITH DECREASING WINDS SAT NIGHT SEE NO REASON LOWS WON/T GET AT LEAST AS COOL AS LATEST MEX MOST AREAS. THIS COULD LEAD TO SCATTERED FROST SUNDAY MORNING IF DWPTS DON/T DRY OUT TOO MUCH. NO FROST WAS MENTIONED AT THIS TIME...BUT IT IS CERTAINLY POSSIBLE. WARMING TREND STILL ON TRACK THEN INTO NEXT WEEK WITH TUESDAY LOOKING EXCEPTIONALLY WARM AHEAD OF COOL FRONT THAT SHOULD KNOCK A FEW DEGREES OFF OF HIGHS BY DAY 7. A DRY FORECAST WAS MAINTAINED IN THE EXTENDED UNTIL ALONG AND POST FRONTAL TUE NIGHT/WEDNESDAY. CHERMOK && .AVIATION... 18Z TAFS FOR KOFK...KLNK AND KOMA. A COUPLE OF WEATHER FEATURES IN THE PROXIMITY OF EASTERN NEBRASKA WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS IN THE FORECAST THROUGH THIS EVENING AND A FEW SHOWERS OR SOME DRIZZLE INTO THURSDAY. CIGS WILL GENERALLY BE VFR WITH SOME PATCHY MVFR CIGS AND VSBYS WITH THE SCATTERED RAINSHOWERS IN THE AREA. AS HEATING CONTINUES THIS AFTERNOON SHOULD SEE ADDITIONAL SHOWER DEVELOPMENT ALONG WITH SOME ISOLATED THUNDERSTORMS. LATER TONIGHT THE BETTER CHANCE FOR THUNDERSTORMS WILL BE ACROSS KANSAS AND SOUTH OF THE TAF SITES. THUNDERSTORM POTENTIAL TOO LOW TO MENTION IN THE TAFS THIS AFTERNOON AND TONIGHT. MVFR AND IFR CIGS AREA FORECAST TO BECOME MORE WIDESPREAD AFTER 06Z. SOUTH WINDS SHIFT TO THE NORTHEAST THEN NORTHWEST AND INCREASE TO ABOVE 15KTS AFTER 15Z. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
651 PM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LOW WILL LIFT NORTH AND AWAY FROM THE AREA OVERNIGHT. HIGH PRESSURE WILL BRING WARMER AND DRIER CONDITIONS THURSDAY AND FRIDAY. SHOWERS AND THUNDERSTORMS WILL RETURN OVER THE WEEKEND AS A COLD FRONT CROSSES THE REGION. STRONG HIGH PRESSURE BUILDING INTO THE AREA EARLY NEXT WEEK WILL BRING MUCH COOLER WEATHER. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 6:45 PM WEDNESDAY...A BROKEN LINE OF LIGHT TO MODERATE SHOWERS IS ENTERING THE FORECAST AREA FROM THE NW. THIS IS AS ANTICIPATED...SEE PREVIOUS DISCUSSION BELOW. THUS FAR THE CONVECTION HAS STAYED WEST OF I-95. WILL UPDATE FORECAST IF THE SHOWERS SHOW ANY SIGN OF MAKING IT MUCH FURTHER EAST. HAVE ADJUSTED THE TEMPERATURE CURVE IN THE GRIDDED DATABASE TO REFLECT SLOWER THAN EXPECTED COOLING. FORECAST OTHERWISE REMAINS ON TRACK WITH LATEST UPDATE. LARGE UPPER LOW CONTINUES TO INFLUENCE THE SENSIBLE WEATHER ACROSS THE AREA AS EVIDENCED BY COUNTERCLOCKWISE ROTATING CLOUD SHIELD ON VISIBLE IMAGERY. IMPACTS TODAY ARE DISPLACED MUCH FURTHER NORTH THAN YESTERDAY THANKS TO THE LOW PROGRESSING SLOWLY NE...BUT THE SLIGHTLY STEEPENED ML LAPSE RATES BENEATH THE 500MB COLD POOL ARE CREATING WIDESPREAD DIURNAL CU TODAY. WHILE SURFACE TEMPS HAVE WARMED WELL INTO THE 70S...SOME MID LEVEL DRY AIR AND WEAK SUBSIDENCE BEHIND THE LOW HAS LIMITED CONVECTION THUS FAR ACROSS THE CWA. HOWEVER...MORE AGITATED CU TO THE NORTH HAS SPAWNED A FEW SHOWERS AND STORMS. HIGH RES GUIDANCE AND SREF PROBS CONTINUE TO INDICATE THAT A FEW SHOWERS WITH AN ISOLATED STORM MAY DEVELOP AND PUSH E/SE INTO THE NORTHERN EDGES OF THE CWA LATE THIS EVE. BASED OFF ONGOING CU DEVELOPMENT...FEEL THIS IS POSSIBLE AND HAVE LEFT SCHC POP THROUGH JUST AFTER NIGHTFALL...FOR I-95 AND NW FROM THERE. THE REST OF THE CWA WILL REMAIN DRY TODAY. ANY CONVECTION WILL DECAY RAPIDLY AFTER DARK LEAVING JUST SCATTERED DEBRIS CLOUDINESS TONIGHT. WEAK PRESSURE GRADIENT WILL HELP WINDS BECOME LIGHT TONIGHT...BUT SOME SLIGHTLY STRONGER LOW LEVEL WINDS WILL KEEP THE SURFACE FROM FULLY DECOUPLING...ESPECIALLY ACROSS THE EASTERN 2/3 OF THE CWA. ADDITIONALLY...SOME RESIDUAL MID LEVEL MOISTURE EVIDENT IN FORECAST SOUNDINGS WILL ALSO HELP LIMIT OVERALL LONGWAVE COOLING. FOR THESE REASONS HAVE GONE SLIGHTLY ABOVE MOS NUMBERS FOR LOWS...MID 50S INLAND TO NEAR 60 AT THE COAST...AND HAVE NOT INCLUDED ANY MENTION OF FOG IN THE WX GRIDS...ALTHOUGH SOME SHALLOW FOG IS POSSIBLE ACROSS INLAND ZONES TOWARDS MORNING. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...A WARMING TREND THE MAIN HEADLINE BOTH THURSDAY AND FRIDAY AS AN UPPER LOW LIFTS AWAY FROM THE AREA AND UPPER HEIGHTS SNAP BACK TO MORE CLIMATOLOGICAL STANDARDS FOR EARLY MAY. COLUMN DRYING INDUCED BY SUBSIDENCE ALOFT WILL PREVAIL THROUGH THURSDAY AND INTO EARLY FRIDAY...SQUELCHING RAIN CHANCES. MOISTURE ADVECTION IN SW FLOW LATE FRIDAY WILL BRING A SLIGHT CHANCE OF PRE-FRONTAL SHOWERS FRIDAY NIGHT. DAYTIME HIGHS IN THE 80S BOTH DAYS...EXCEPT UPPER 70S ALONG THE IMMEDIATE COAST. THE DAYTIME LAND VS WATER TEMPERATURE DIFFERENTIAL BOTH DAYS WILL SERVE AS THE ENGINE THAT DRIVES A ROBUST SEA BREEZE CIRCULATION...WHICH COULD BRING MAXIMUM TEMPERATURES NEAR THE COAST EARLIER IN THE DAY...COMPARED TO THE TYPICAL DIURNAL MAXIMUM HEATING TIME. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 3 PM WEDNESDAY...MEDIUM RANGE GUIDANCE REMAINS STABLE WITH A SIGNIFICANT FRONT SLATED TO MOVE ACROSS THE AREA LATE SUNDAY FOLLOWED BY YET ANOTHER COLD AIR MASS. WPC MID LEVEL GRAPHICS ARE A MIX OF MAINLY THE ECMWF PRODUCTS EARLY IN THE PERIOD FOLLOWED BY A SMATTERING OF GEM AND GFS LATER IN THE PERIOD. FOR SATURDAY...SYNOPTIC FORCING WILL CONSIST OF LOW LEVEL SPEED CONVERGENCE PRODUCING MOSTLY SHOWERS AND STREAMERS OFF THE ATLANTIC. THIS IS A TYPICAL SCENARIO FOR OUR AREA. THE ECMWF IS THE SLOWER OF THE GUIDANCE AND OFFERS THE BEST COUPLING OF INSTABILITY AND FORCING FOR THE COAST SUNDAY AND WE ARE NOW ADVERTISING LIKELY POPS. ENSEMBLES SHOW 500MB HEIGHTS APPROACHING TWO STANDARD DEVIATIONS BELOW NORMAL EARLY NEXT WEEK. 850MB TEMPERATURES DIP TO AROUND THREE DEGREES CELSIUS LATE MONDAY AND TUESDAY. A COUPLED BOUNDARY LAYER WILL LIKELY KEEP OVERNIGHT LOWS A LITTLE ABOVE GUIDANCE. WIDESPREAD LOWS IN THE 40S CAN BE EXPECTED TUESDAY WITH A SMATTERING OF 40S WEDNESDAY MORNING. DOWNSLOPING AND A STRONG MID MAY SUN ANGLE WILL ALLOW DAYTIME TEMPERATURES TO RISE INTO THE 70S. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS CU BEGINNING TO DEVELOP OVER THE CWA WITH DAYTIME HEATING. EXPECT THIS TREND TO CONTINUE THRU THE AFTN WITH SCT CLOUDS 4-5KFT AND SOUTHWEST WINDS 10-15 KTS. HAVE REMOVED VCSH FOR KLBT AS LATEST HRRR RUNS KEEP ALL SHOWER ACTIVITY WELL NORTH OF OUR AREA...AND LATEST SATELLITE SHOWS THAT STILL ONLY SHALLOW CU PRESENT IN THE VICINITY. CLOUD COVER DIMINISHES TONIGHT... BUT ENHANCED LOW-LEVEL WINDS LIKELY WILL LIMIT FOG DEVELOPMENT. IT APPEARS PATCHY FOG IS MOST LIKELY AT KFLO/KLBT...AS THE NEAR SFC WINDS WEAKEN AFTER 06Z AND THE MODEL SOUNDINGS DEPICT BETTER RADIATIONAL COOLING. CONFIDENCE IS STILL FAIRLY LOW...BUT ADDED TEMPO MVFR VSBYS FOR THE INLAND TERMS IN THE 09-12Z TIME FRAME. EXPECT VFR CONDITIONS AGAIN ON THURSDAY WITH W-SW WINDS AOB 10 KTS. EXTENDED OUTLOOK...MVFR/TEMPO IFR IN MORNING FOG FRIDAY. CHANCE OF SHOWERS SATURDAY AND SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 6:45 PM WEDNESDAY...LATEST OBS SHOW 2 TO 4 FT SEAS WITH SW WINDS IN THE 15 KT RANGE. NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: BROAD LOW PRESSURE TO THE NW OF THE WATERS WILL KEEP SW WINDS ONGOING THROUGH THE PERIOD..WITH THE SLIGHT ENHANCEMENT IN THE NEAR-SHORE WATERS DUE TO THE SEA BREEZE WEAKENING AFTER SUNSET. WINDS WILL REMAIN 10-15 KTS ACROSS THE WATERS THROUGH TONIGHT...WITH SCATTERED GUSTS ABOVE 20 KTS POSSIBLE. SEAS WILL BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE DECREASING EASTERLY SWELL...WHICH WILL CREATE SHORTENING PERIODS. EXPECT PREDOMINANTLY 2-4 FT SEAS THROUGH TONIGHT...WITH A 10 SEC EASTERLY SWELL AND 5 SEC SW WIND WAVE COMPRISING THE SPECTRUM. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...MODERATE SW WINDS TO PREVAIL THU AND FRI AS HIGH PRESSURE REMAINS POSITIONED OVER THE OFFSHORE WATERS WITH WEAK LOW PRESSURE INLAND. GENERALLY 15 KNOTS OR LESS...EXCEPT GUSTS TO 20 KT IN THE MIDDLE AFTERNOON TO EARLY EVENING NEAR SHORE IN THE PEAK OF THE SEA BREEZE CIRCULATION INDUCED BY LAND HEATING. SEAS GENERALLY 2-4 FT AND HIGHEST OFFSHORE...COMPOSED OF MODERATE SW CHOP MIXED WITH 1-2 SE WAVES EVERY 7-8 SECONDS. NO TSTMS OR RESTRICTIONS TO VISIBILITY EXPECTED ON THE WATERS THU AND FRI BUT A FEW SHOWERS MAY DOT THE WATERS FRIDAY NIGHT. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 PM WEDNESDAY...SOUTHWESTERLY FLOW WILL PREVAIL SATURDAY AND MOST OF THE DAY SUNDAY AHEAD OF A RELATIVELY SLOW MOVING COLD FRONT. SPEEDS WILL BE MAINLY IN A RANGE OF 10-15 KNOTS MOSTLY TOWARD THE HIGHER END. THE FRONT MOVES ACROSS THE WATERS SUNDAY NIGHT WITH A NORTHERLY FLOW IN ITS WAKE. WIND SPEEDS INCREASE TO 15-20 KNOTS. SIGNIFICANT SEAS SHOW MOSTLY 2-4 FEET SATURDAY AND SUNDAY INCREASING TO 3-5 FEET WITH THE INCREASE IN WINDS EARLY MONDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...REK/JDW SHORT TERM...MJC LONG TERM...SHK AVIATION...MRR MARINE...MJC/REK/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
314 PM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LOW WILL LIFT NORTH AND AWAY FROM THE AREA OVERNIGHT. HIGH PRESSURE WILL BRING WARMER AND DRIER CONDITIONS THURSDAY AND FRIDAY. SHOWERS AND THUNDERSTORMS WILL RETURN OVER THE WEEKEND AS A COLD FRONT CROSSES THE REGION. STRONG HIGH PRESSURE BUILDING INTO THE AREA EARLY NEXT WEEK WILL BRING MUCH COOLER WEATHER. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM WEDNESDAY...LARGE UPPER LOW CONTINUES TO INFLUENCE THE SENSIBLE WEATHER ACROSS THE AREA AS EVIDENCED BY COUNTERCLOCKWISE ROTATING CLOUD SHIELD ON VISIBLE IMAGERY. IMPACTS TODAY ARE DISPLACED MUCH FURTHER NORTH THAN YESTERDAY THANKS TO THE LOW PROGRESSING SLOWLY NE...BUT THE SLIGHTLY STEEPENED ML LAPSE RATES BENEATH THE 500MB COLD POOL ARE CREATING WIDESPREAD DIURNAL CU TODAY. WHILE SURFACE TEMPS HAVE WARMED WELL INTO THE 70S...SOME MID LEVEL DRY AIR AND WEAK SUBSIDENCE BEHIND THE LOW HAS LIMITED CONVECTION THUS FAR ACROSS THE CWA. HOWEVER...MORE AGITATED CU TO THE NORTH HAS SPAWNED A FEW SHOWERS AND STORMS. HIGH RES GUIDANCE AND SREF PROBS CONTINUE TO INDICATE THAT A FEW SHOWERS WITH AN ISOLATED STORM MAY DEVELOP AND PUSH E/SE INTO THE NORTHERN EDGES OF THE CWA LATE THIS EVE. BASED OFF ONGOING CU DEVELOPMENT...FEEL THIS IS POSSIBLE AND HAVE LEFT SCHC POP THROUGH JUST AFTER NIGHTFALL...FOR I-95 AND NW FROM THERE. THE REST OF THE CWA WILL REMAIN DRY TODAY. ANY CONVECTION WILL DECAY RAPIDLY AFTER DARK LEAVING JUST SCATTERED DEBRIS CLOUDINESS TONIGHT. WEAK PRESSURE GRADIENT WILL HELP WINDS BECOME LIGHT TONIGHT...BUT SOME SLIGHTLY STRONGER LOW LEVEL WINDS WILL KEEP THE SURFACE FROM FULLY DECOUPLING...ESPECIALLY ACROSS THE EASTERN 2/3 OF THE CWA. ADDITIONALLY...SOME RESIDUAL MID LEVEL MOISTURE EVIDENT IN FORECAST SOUNDINGS WILL ALSO HELP LIMIT OVERALL LONGWAVE COOLING. FOR THESE REASONS HAVE GONE SLIGHTLY ABOVE MOS NUMBERS FOR LOWS...MID 50S INLAND TO NEAR 60 AT THE COAST...AND HAVE NOT INCLUDED ANY MENTION OF FOG IN THE WX GRIDS...ALTHOUGH SOME SHALLOW FOG IS POSSIBLE ACROSS INLAND ZONES TOWARDS MORNING. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...A WARMING TREND THE MAIN HEADLINE BOTH THURSDAY AND FRIDAY AS AN UPPER LOW LIFTS AWAY FROM THE AREA AND UPPER HEIGHTS SNAP BACK TO MORE CLIMATOLOGICAL STANDARDS FOR EARLY MAY. COLUMN DRYING INDUCED BY SUBSIDENCE ALOFT WILL PREVAIL THROUGH THURSDAY AND INTO EARLY FRIDAY...SQUELCHING RAIN CHANCES. MOISTURE ADVECTION IN SW FLOW LATE FRIDAY WILL BRING A SLIGHT CHANCE OF PRE-FRONTAL SHOWERS FRIDAY NIGHT. DAYTIME HIGHS IN THE 80S BOTH DAYS...EXCEPT UPPER 70S ALONG THE IMMEDIATE COAST. THE DAYTIME LAND VS WATER TEMPERATURE DIFFERENTIAL BOTH DAYS WILL SERVE AS THE ENGINE THAT DRIVES A ROBUST SEA BREEZE CIRCULATION...WHICH COULD BRING MAXIMUM TEMPERATURES NEAR THE COAST EARLIER IN THE DAY...COMPARED TO THE TYPICAL DIURNAL MAXIMUM HEATING TIME. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 3 PM WEDNESDAY...MEDIUM RANGE GUIDANCE REMAINS STABLE WITH A SIGNIFICANT FRONT SLATED TO MOVE ACROSS THE AREA LATE SUNDAY FOLLOWED BY YET ANOTHER COLD AIR MASS. WPC MID LEVEL GRAPHICS ARE A MIX OF MAINLY THE ECMWF PRODUCTS EARLY IN THE PERIOD FOLLOWED BY A SMATTERING OF GEM AND GFS LATER IN THE PERIOD. FOR SATURDAY...SYNOPTIC FORCING WILL CONSIST OF LOW LEVEL SPEED CONVERGENCE PRODUCING MOSTLY SHOWERS AND STREAMERS OFF THE ATLANTIC. THIS IS A TYPICAL SCENARIO FOR OUR AREA. THE ECMWF IS THE SLOWER OF THE GUIDANCE AND OFFERS THE BEST COUPLING OF INSTABILITY AND FORCING FOR THE COAST SUNDAY AND WE ARE NOW ADVERTISING LIKELY POPS. ENSEMBLES SHOW 500MB HEIGHTS APPROACHING TWO STANDARD DEVIATIONS BELOW NORMAL EARLY NEXT WEEK. 850MB TEMPERATURES DIP TO AROUND THREE DEGREES CELSIUS LATE MONDAY AND TUESDAY. A COUPLED BOUNDARY LAYER WILL LIKELY KEEP OVERNIGHT LOWS A LITTLE ABOVE GUIDANCE. WIDESPREAD LOWS IN THE 40S CAN BE EXPECTED TUESDAY WITH A SMATTERING OF 40S WEDNESDAY MORNING. DOWNSLOPING AND A STRONG MID MAY SUN ANGLE WILL ALLOW DAYTIME TEMPERATURES TO RISE INTO THE 70S. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS CU BEGINNING TO DEVELOP OVER THE CWA WITH DAYTIME HEATING. EXPECT THIS TREND TO CONTINUE THRU THE AFTN WITH SCT CLOUDS 4-5KFT AND SOUTHWEST WINDS 10-15 KTS. HAVE REMOVED VCSH FOR KLBT AS LATEST HRRR RUNS KEEP ALL SHOWER ACTIVITY WELL NORTH OF OUR AREA...AND LATEST SATELLITE SHOWS THAT STILL ONLY SHALLOW CU PRESENT IN THE VICINITY. CLOUD COVER DIMINISHES TONIGHT... BUT ENHANCED LOW-LEVEL WINDS LIKELY WILL LIMIT FOG DEVELOPMENT. IT APPEARS PATCHY FOG IS MOST LIKELY AT KFLO/KLBT...AS THE NEAR SFC WINDS WEAKEN AFTER 06Z AND THE MODEL SOUNDINGS DEPICT BETTER RADIATIONAL COOLING. CONFIDENCE IS STILL FAIRLY LOW...BUT ADDED TEMPO MVFR VSBYS FOR THE INLAND TERMS IN THE 09-12Z TIME FRAME. EXPECT VFR CONDITIONS AGAIN ON THURSDAY WITH W-SW WINDS AOB 10 KTS. EXTENDED OUTLOOK...MVFR/TEMPO IFR IN MORNING FOG FRIDAY. CHANCE OF SHOWERS SATURDAY AND SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM WEDNESDAY...BROAD LOW PRESSURE TO THE NW OF THE WATERS WILL KEEP SW WINDS ONGOING THROUGH THE PERIOD..WITH THE SLIGHT ENHANCEMENT IN THE NEAR-SHORE WATERS DUE TO THE SEA BREEZE WEAKENING AFTER SUNSET. WINDS WILL REMAIN 10-15 KTS ACROSS THE WATERS THROUGH TONIGHT...WITH SCATTERED GUSTS ABOVE 20 KTS POSSIBLE. SEAS WILL BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE DECREASING EASTERLY SWELL...WHICH WILL CREATE SHORTENING PERIODS. EXPECT PREDOMINANTLY 2-4 FT SEAS THROUGH TONIGHT...WITH A 10 SEC EASTERLY SWELL AND 5 SEC SW WIND WAVE COMPRISING THE SPECTRUM. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...MODERATE SW WINDS TO PREVAIL THU AND FRI AS HIGH PRESSURE REMAINS POSITIONED OVER THE OFFSHORE WATERS WITH WEAK LOW PRESSURE INLAND. GENERALLY 15 KNOTS OR LESS...EXCEPT GUSTS TO 20 KT IN THE MIDDLE AFTERNOON TO EARLY EVENING NEAR SHORE IN THE PEAK OF THE SEA BREEZE CIRCULATION INDUCED BY LAND HEATING. SEAS GENERALLY 2-4 FT AND HIGHEST OFFSHORE...COMPOSED OF MODERATE SW CHOP MIXED WITH 1-2 SE WAVES EVERY 7-8 SECONDS. NO TSTMS OR RESTRICTIONS TO VISIBILITY EXPECTED ON THE WATERS THU AND FRI BUT A FEW SHOWERS MAY DOT THE WATERS FRIDAY NIGHT. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 PM WEDNESDAY...SOUTHWESTERLY FLOW WILL PREVAIL SATURDAY AND MOST OF THE DAY SUNDAY AHEAD OF A RELATIVELY SLOW MOVING COLD FRONT. SPEEDS WILL BE MAINLY IN A RANGE OF 10-15 KNOTS MOSTLY TOWARD THE HIGHER END. THE FRONT MOVES ACROSS THE WATERS SUNDAY NIGHT WITH A NORTHERLY FLOW IN ITS WAKE. WIND SPEEDS INCREASE TO 15-20 KNOTS. SIGNIFICANT SEAS SHOW MOSTLY 2-4 FEET SATURDAY AND SUNDAY INCREASING TO 3-5 FEET WITH THE INCREASE IN WINDS EARLY MONDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...MJC LONG TERM...SHK AVIATION...BJR/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
127 PM EDT WED MAY 8 2013 .SYNOPSIS... LOW PRESSURE...TO OUR NORTH...WILL CONTINUE TO MOVE SLOWLY AWAY FROM THE AREA THROUGH TONIGHT. HIGH PRESSURE WILL FILL IN BEHIND THE DEPARTING LOW...BRINGING WARMER AND DRIER CONDITIONS. SHOWERS AND THUNDERSTORMS WILL RETURN DURING THE WEEKEND AHEAD OF A COLD FRONT. COOL AND DRY HIGH PRESSURE WILL BUILD INTO THE AREA EARLY NEXT WEEK WITH NEAR RECORD LOWS FORECAST FOR MONDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM WEDNESDAY...LARGE UPPER LOW CLEARLY EVIDENT ON WV IMAGERY CENTERED OVER VA WILL CONTINUE TO IMPACT THE SYNOPTIC REGIME TODAY...ALTHOUGH WITH A GRADUALLY WEAKENING EFFECT. AMPLE SUNSHINE THIS MORNING HAS ALLOWED TEMPS TO SOAR QUICKLY...AND SIGNIFICANT ADJUSTMENTS HAVE BEEN MADE TO THE HOURLY CURVE...FORCING MINOR UPTICKS IN FORECAST HIGHS FOR TODAY. ANTICIPATE MANY PLACES WILL REACH WELL INTO THE 70S TODAY AWAY FROM THE IMMEDIATE COAST...APPROACHING 80 IN THE SW PEE DEE ZONES. WITH UPPER LOW STILL KEEPING ITS BROAD INFLUENCE OVERHEAD...LOW LEVEL AND MID-LEVEL LAPSE RATES WILL BE RATHER STEEP TODAY...AND ANTICIPATE INCREASING DIURNAL CONVECTION IN THE FORM OF AFTN CU. WHILE LOW DRIFTS NE THROUGH THE DAY...500MB TEMPS SLOWLY RISE WHICH FORCES SLOWLY WEAKENING LAPSE RATES AND THIS WILL INHIBIT MUCH IN THE WAY OF SHOWER/TSTM CHANCES. HIGH RES WRF/HRRR KEEP THE AREA DRY TODAY...BUT HAVE CONTINUED SCHC POP IN THE FAR WEST AND NORTH FOR ISOLATED COVERAGE DUE TO PROXIMITY TO COOLER UPPER LEVEL TEMPS. GUIDANCE DEPICTING 300-700 J/KG OF SBCAPE ACROSS THESE AREAS THIS AFTN WHICH COULD BE ENOUGH TO DRIVE AN UPDRAFT STRONGLY ENOUGH TO OBTAIN CHARGE SEPARATION AND LIGHTNING...BUT THIS IS ONLY POSSIBLE WHERE MAX TEMPS REACH 76 OR HIGHER. AT THE SAME TIME...WITH WESTERLY STEERING FLOW...ANY STORMS THAT DEVELOP N/W OF THE AREA MAY SLIP INTO THE CWA AS WELL...HENCE MAINTAINING THE SCHC POP. CONVECTION WILL WANE RAPIDLY WITH LOSS OF HEATING...AND ALTHOUGH MODERATE RADIATIONAL COOLING IS EXPECTED...MINS WILL BE A LITTLE WARMER THAN LAST NIGHT...FALLING INTO THE MID 50S INLAND...UPPER 50S AT THE COAST. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY...DEEP W-NW FLOW AND SUBSIDENCE ON THE BACK END OF DEPARTING LOW PRESSURE SYSTEM WILL AID IN PRODUCING PLENTY OF SUNSHINE AND WARM TEMPS ON THURS AND FRI. MODELS ARE HINTING AT SOME CU DEVELOPMENT ALONG SEA BREEZE BOUNDARY THURS AFTN BUT NO PCP EXPECTED. WEAK HIGH PRESSURE AT THE SURFACE AND RIDGING ALOFT THURS NIGHT INTO EARLY FRI WILL PROVIDE FURTHER DRYING ESPECIALLY THROUGH THE MID LEVELS AS WELL AS INCREASED WARMING WITH TEMPS REACHING INTO THE MID 80S...SEVERAL DEGREES ABOVE NORMAL. BY LATE FRI INTO SATURDAY SOUTHWESTERLY RETURN FLOW WILL INCREASE AS MID TO UPPER TROUGH PUSHES A COLD FRONT EAST REACHING CLOSER TO THE CAROLINAS. MOISTURE THROUGH THE COLUMN WILL INCREASE AS PCP WATER VALUES REACH UP CLOSE TO 1.5 INCHES BY FRI EVENING. WILL CONTINUE TO INCLUDE SLIGHT CHC POPS ASSOCIATED WITH SEA BREEZE CONVERGENCE FRI AFTN BUT WILL SEE INCREASE IN CLOUDS AND CHC OF SHWRS LATE FRI INTO SATURDAY MORNING IN INCREASINGLY WARM MOIST SOUTHERLY FLOW. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY...MID TO UPPER TROUGH WILL PUSH COLD FRONT EAST THROUGH THE CAROLINAS ON SATURDAY CROSSING OUR LOCAL CWA ON SUNDAY. INCREASING WARM AND MOIST SOUTHERLY FLOW COMBINED WITH BETTER UPPER DYNAMICS WILL INCREASE CHC OF SHWRS/TSTMS SAT AND SUNDAY. EXPECT BETTER COVERAGE INLAND ON SATURDAY AND CLOSER TO THE COAST ON SUNDAY JUST AHEAD AND ALONG COLD FRONT BEFORE IT SHIFTS OFF THE COAST BY SUN AFTN. PCP WATER VALUES INCREASE UP AROUND 1.5 INCHES INLAND ON SATURDAY AND EXPECT BETTER COVERAGE AS SEA BREEZE BOUNDARY PUSHES INLAND. MODELS SHOW SURGE OF MOISTURE THROUGH EARLY SUNDAY IN 45 LLJ JUST AHEAD OF COLD FRONT. PCP WATER VALUES INCREASE UP AROUND 1.75 INCHES...ESPECIALLY CLOSER TO THE COAST ON SUNDAY AS STEERING FLOW SHIFTS AROUND FROM SW TO WEST AS COLD FRONT MOVES THROUGH. VERY DRY AND UNSEASONABLY COOL AIR WILL MAKE ITS WAY IN BEHIND COLD FRONT LATE SUNDAY THROUGH EARLY NEXT WEEK. BEST CAA WILL COME OVERNIGHT SUNDAY INTO MONDAY IN DEEP NORTHERLY FLOW. GFS SHOWS 850 TEMPS PLUMMETING LATE SUNDAY THROUGH MONDAY BOTTOMING OUT EARLY TUES BEFORE REBOUNDING. VALUES UP NEAR 14C SAT AFTN DROP DOWN CLOSE TO 1 C THROUGH EARLY TUES. EXPECT TEMPS UP IN THE 80S WITH DEWPOINT TEMPS IN THE MID 60S ON SAT INTO EARLY SUNDAY AHEAD OF COLD FRONT. BY MONDAY TEMPS WILL BE HARD PRESSED TO MAKE IT INTO THE 70S ALTHOUGH MAY SUNSHINE SHOULD HELP THEM ALONG. DEWPOINT TEMPS WILL DROP INTO THE 40S AND MAY SEE 30S INLAND. BETTER CAA SUNDAY NIGHT WILL BRING OVERNIGHT LOWS DOWN CLOSER TO 50 BUT MONDAY NIGHT HIGH PRESSURE WILL BE NEARLY OVERHEAD WITH MORE IDEAL RADIATIONAL COOLING CONDITIONS TO HELP BRING TEMPS DOWN INTO THE 40S. MAY SEE TEMPS FLIRT WITH RECORD LOWS MONDAY NIGHT INTO EARLY TUES. AFTER A COLD START TUES MORNING TEMPS WILL REBOUND TO AROUND 70 WITH PLENTY OF SUNSHINE. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS CU BEGINNING TO DEVELOP OVER THE CWA WITH DAYTIME HEATING. EXPECT THIS TREND TO CONTINUE THRU THE AFTN WITH SCT CLOUDS 4-5KFT AND SOUTHWEST WINDS 10-15 KTS. HAVE REMOVED VCSH FOR KLBT AS LATEST HRRR RUNS KEEP ALL SHOWER ACTIVITY WELL NORTH OF OUR AREA...AND LATEST SATELLITE SHOWS THAT STILL ONLY SHALLOW CU PRESENT IN THE VICINITY. CLOUD COVER DIMINISHES TONIGHT... BUT ENHANCED LOW-LEVEL WINDS LIKELY WILL LIMIT FOG DEVELOPMENT. IT APPEARS PATCHY FOG IS MOST LIKELY AT KFLO/KLBT...AS THE NEAR SFC WINDS WEAKEN AFTER 06Z AND THE MODEL SOUNDINGS DEPICT BETTER RADIATIONAL COOLING. CONFIDENCE IS STILL FAIRLY LOW...BUT ADDED TEMPO MVFR VSBYS FOR THE INLAND TERMS IN THE 09-12Z TIME FRAME. EXPECT VFR CONDITIONS AGAIN ON THURSDAY WITH W-SW WINDS AOB 10 KTS. EXTENDED OUTLOOK...MVFR/TEMPO IFR IN MORNING FOG FRIDAY. CHANCE OF SHOWERS SATURDAY AND SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM WEDNESDAY...BROAD LOW PRESSURE TO THE NW OF THE WATERS WILL KEEP SW WINDS ONGOING THROUGH THE PERIOD...ALTHOUGH A SLIGHT BACKING TO S/SW WILL OCCUR IN THE NEAR SHORE WATERS THIS AFTN DUE TO A DEVELOPING SEA BREEZE. WINDS SPEEDS WILL ALSO BE IMPACTED BY THIS SEA BREEZE...BEING 10-15 KTS ACROSS MOST OF THE WATERS...BUT GUSTING TO 20 KTS WITHIN THE SEA BREEZE AFFECTED AREAS. SEAS WILL BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE DECREASING EASTERLY SWELL TODAY...WHICH WILL CREATE SHORTENING PERIODS. EXPECT PREDOMINANTLY 2-4 FT SEAS THROUGH TONIGHT...WITH A 10 SEC EASTERLY SWELL AND 5 SEC SW WIND WAVE COMPRISING THE SPECTRUM. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY...DEPARTING LOW PRESSURE SYSTEM WILL LEAVE BEHIND WEAK HIGH PRESSURE OVER THE LOCAL WATERS ON THURSDAY. A WEAK RETURN FLOW ON THURS WILL INCREASE THROUGH FRIDAY AS HIGH PRESSURE SHIFTS OFF SHORE AND COLD FRONT APPROACHES THE CAROLINAS FROM THE WEST. WINDS WILL GENERALLY BE OUT OF THE SOUTHWEST 10 TO 15 KTS THROUGH THURS INTO FRI AND MAY INCREASE TO A SOLID 15 KTS BY FRI NIGHT AS GRADIENT BEGINS TO TIGHTEN. SEAS WILL DIMINISH SLIGHTLY THURS INTO FRI REMAINING AROUND 3 FT OR LESS THROUGH MOST OF THE PERIOD. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY...GRADIENT WILL TIGHTEN WITH INCREASING SOUTHERLY FLOW THROUGH SAT AHEAD OF APPROACHING COLD FRONT. A PERSISTENT SOUTHERLY PUSH UP AROUND 15 KTS WILL DRIVE SEAS UP THROUGH SATURDAY BUT A SHARPER RISE WILL OCCUR SAT NIGHT AS COLD FRONT DRAWS CLOSER AND WINDS INCREASE UP TO 20 KTS. EXPECT SEAS TO RISE TO NEAR SCA THRESHOLDS BY SUNDAY MORNING JUST AHEAD OF COLD FRONT. WINDS AND SEAS MAY DIMINISH SLIGHTLY AS THE WINDS VEER AROUND BEHIND COLD FRONT THROUGH LATE SUNDAY BUT A SURGE SUN NIGHT IN DECENT CAA WILL PUSH SEAS UP AGAIN JUST NEAR SCA THRESHOLDS. NEAR SHORE SEAS WILL BE GREATEST SAT NIGHT INTO EARLY SUNDAY IN SOUTHERLY FLOW AHEAD OF FRONT BUT SEAS IN THE OUTER WATERS MAY BE GREATER THROUGH EARLY NEXT WEEK IN COLD SURGE BEHIND FRONT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...RGZ LONG TERM...RGZ AVIATION...BJR/JDW MARINE...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1250 PM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY. && .NEAR TERM /THROUGH THURSDAY NIGHT/... AS OF 1050 AM WEDNESDAY... MORNING UPDATE AS OF 1050 AM EDT: CURRENT SATELLITE SHOWS A VORTICITY MAX EMBEDDED WITHIN THE LARGER CLOSED LOW SLOWLY DRIFTING SE ACROSS ERN WVA. THE LEADING EDGE OF RAIN AHEAD OF THIS FEATURE IS NOW APPROACHING OUR NW ZONES. LATEST HRRR HAS A DECENT HANDLE ON THIS RAIN AND TIMING...AND SHOWS IT MOVING ACROSS OUR NORTHERN ZONES WHILE DIMINISHING IN COVERAGE THROUGH EARLY/MID AFTERNOON. MEANWHILE ADDITIONAL CONVECTIVE CELLS ARE SHOWN IN THE HRRR DEVELOPING ACROSS THE FOOTHILLS DURING THE EARLY AFTERNOON THEN MOVING EASTWARD ACROSS OUR PIEDMONT ZONES THROUGH 00Z. LATEST VIS SATELLITE SHOWS THE BEST OPPORTUNITY FOR SUNSHINE AND SFC HEATING ACROSS THE SOUTHERN HALF OF OUR CWA...THUS LENDING SUPPORT TO THE MODEL DEPICTION OF CONVECTIVE CELL DEVELOPMENT LATER THIS AFTERNOON. HOWEVER...FORECAST SOUNDINGS FOR LATER TODAY SUGGEST MID AND UPPER LEVEL WARMING AS THE UPPER LOW LIFTS NE...AND SHOULD LIMIT OVERALL CAPE AND TSTM/SEVERE POTENTIAL. IF VIGOROUS TSTM UPDRAFTS CAN DEVELOP...CAN`T RULE OUT SOME SMALL HAIL AND PERHAPS BRIEF/ISOLATED STRONG WIND GUSTS WITH ANY OF THE MORE POTENT CELLS. OTHERWISE...WITH EXTENSIVE CLOUDS AND LIGHT RAIN ACROSS OUR NORTHERN ZONES...TEMPS HAVE BEEN SLOWER TO RISE THERE...SO WILL MAKE A FEW SUBTLE DOWNWARD TWEAKS THERE FOR AFTERNOON TEMPS. LOOK FOR HIGHS TODAY TO RANGE FROM THE UPPER 60S NORTH TO MID 70S SOUTH. PREV NEAR TERM DISC ISSUED 310 AM EDT: ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY. FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND WRN PIEDMONT. THE MID-UPPER LEVEL LOW THAT HAS PLAGUED THE REGION FOR DAYS IS LOCATED AROUND RNK EARLY THIS MORNING... AND IS EXPECTED TO DRIFT TOWARD THE NNE ALONG THE ERN SLOPES OF THE APPALACHIANS INTO PA TONIGHT. ABOVE-NORMAL PRECIP WATER WILL CONTINUE TO ROTATE ABOUT THE NEARLY STACKED CYCLONE... AND MODELS SHOW OVERALL PRECIP WATER INCREASING FROM JUST UNDER AN INCH THIS MORNING TO NEARLY 1.2 INCHES -- CLOSE TO 150% OF NORMAL -- OVER CENTRAL/ERN NC THIS AFTERNOON. WITH LOW LEVEL WARM AIR ADVECTION AND THE POCKET OF SLIGHTLY COOLER MID LEVEL TEMPS OVER NRN/WRN NC... EXPECT THE COLUMN TO DESTABILIZE BY AFTERNOON... AND BOTH THE NAM AND RAP MODELS SHOW MLCAPE INCREASING TO 600-1200 J/KG LATER TODAY SPREADING IN FROM THE SW. AS THE LOW ALOFT LIFTS AWAY FROM NC... MID LEVEL FLOW STRENGTHENS QUICKLY FROM LESS THAN 20 KTS EARLY THIS MORNING TO 35-40 KTS FROM THE W AND WNW THIS AFTERNOON... AND THIS SHOULD FOSTER STORM ORGANIZATION DESPITE THE MARGINAL INSTABILITY. DYNAMIC SUPPORT FROM VORTICITY LOBES ROTATING AROUND THE LOW AS WELL AS A QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A NORTHWESTERLY 50-KT UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD ALSO ENCOURAGE STORM DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED SHOWERS FINISH THEIR JOURNEY THROUGH CENTRAL NC THIS MORNING... EXPECTED SCATTERED SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE HIGHER TERRAIN OF NW NC INTO THE TRIAD REGION... THEN INCREASING IN COVERAGE AS THEY PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC DURING THE AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC WRF. GIVEN THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD BECOME STRONG WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH WILL DEPEND ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND THIS IN TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD COVER PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE CLOUDS AND SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND QUICKLY RISING CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS. EXPECT HIGHS FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE AND FACTORING IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE MEAGER DYNAMIC SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID LEVEL LOW... AND WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL AFTER NIGHTFALL ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL FLOW AND DRYING... SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT... FOLLOWED BY GRADUAL CLEARING WEST TO EAST. LOWS 53-58. FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 315 AM WEDNESDAY... SPLIT FLOW PATTERN OVER THE CONUS LATE THIS WEEK WILL BECOME DOMINATED BY THE NORTHERN STREAM BY THIS WEEKEND AS A STRONG SHORTWAVE BEGINS TO CARVE OUT A DEEP TROUGH OVER THE EASTERN US. AHEAD OF THIS SYSTEM...RIDGING OVER OUR REGION WILL WEAKEN AS A LEAD SHORTWAVE MOVES THROUGH THE MIDWEST STATES. THE ASSOCIATED FRONTAL ZONE WILL MOVE SLOWLY TO THE EAST AND APPROACH THE APPALACHIANS SATURDAY. THE MORE UNSTABLE WARM SECTOR AIRMASS WILL BE WEST OF THE MOUNTAINS ON FRIDAY...ALTHOUGH FORECAST SOUNDINGS SUGGEST MLCAPE MAY REACH 500-1000 J/KG FRIDAY AFTERNOON AS THE UPPER RIDGE WEAKENS. DEEP LAYER SOUTHWESTERLY FLOW SHOULD BE RELATIVELY WEAK...MAKING IT DIFFICULT FOR MUCH MORE THAN A FEW ISOLATED STORMS TO MOVE INTO THE WESTERN PIEDMONT. FRIDAY WILL BE THE WARMEST DAY OF THE PERIOD WITH PARTLY CLOUDY TO MOSTLY SUNNY SKIES. LOW LEVEL THICKNESSES SURPASSING 1390M AND A SOUTHWESTERLY WIND SUGGEST HIGHS IN THE LOW TO MID 80S. LOWS FRIDAY NIGHT IN THE LOW TO MID 60S. GRADUAL HEIGHT FALLS AHEAD OF THE AFOREMENTIONED UPPER TROUGH MOVING SOUTH OUT OF CANADA WILL HELP TO SHARPEN THE LEE TROUGH SATURDAY AS A THE COLD FRONT APPROACHES FROM THE WEST. WITH WEAK TO MODERATE INSTABILITY POSSIBLE...DEPENDING ON THE AMOUNT REGIONAL CLOUD COVER SATURDAY MORNING....AND DEEP LAYER SHEAR INCREASING TO AROUND 30KT...THERE WILL BE A BETTER CHANCE OF STRONG STORMS SATURDAY AFTERNOON. HIGHS 76-83 WEST TO EAST. EVEN WITH THE LOSS OF HEATING SATURDAY NIGHT...SOME CONVECTION SHOULD STILL BE ABLE TO PERSIST AS THE LEAD FRONTAL ZONE MOVES INTO CENTRAL NC. WILL MAINTAIN A CHANCE POP THROUGH THE OVERNIGHT HOURS...WITH LOWS IN THE LOW TO MID 60S. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 315 AM WEDNESDAY... THE COLD FRONT CROSSING THE AREA SATURDAY NIGHT SHOULD EFFECTIVELY SHIFT TO THE COASTAL PLAIN SUNDAY MORNING...WHILE A SECONDARY AND STRONGER POLAR FRONT SWINGS INTO THE AREA FROM THE NORTHWEST. CHANCES OF PRECIP WILL BE PRIMARILY FOCUSED OVER THE COASTAL PLAIN WHERE ANY APPRECIABLE INSTABILITY WOULD BE MORE LIKELY. HIGHS BEGIN THEIR MORE SIGNIFICANT DOWNWARD TREND SUNDAY AND PARTICULARLY MONDAY AS THE AFOREMENTIONED POLAR FRONT CROSSES THE AREA AND A DEEP UPPER TROUGH DEVELOPS OVER THE EASTERN US. HIGHS IN THE MID 70S SUNDAY WILL FALL WELL BELOW NORMAL INTO THE MID TO UPPER 60S MONDAY AND TUESDAY. THERE IS MEDIUM TO HIGH CONFIDENCE IN THESE BELOW NORMAL TEMPS AND DRY CONDITIONS DURING THE FIRST PART OF NEXT WEEK.. && .AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... AS OF 1250 PM WEDNESDAY... CURRENT RGNL SAT/RADAR SHOWING EXTENSIVE CLOUD COVER...BUT NOT MUCH IN THE WAY OF PRECIP AFFECTING OUR TAFS SITES ATTM. MOST CA MODELS STILL INDICATE SCATTERED SHOWERS DEVELOPING AS THE AFTERNOON PROGRESSES...AND THIS SEEMS REASONABLE GIVEN THE UPPER IMPULSE TO OUR NORTH. WHILE THERE ARE SOME SCAT CLOUDS BELOW 3KFT...CIGS ARE ALL VFR ACROSS CENTRAL NC ATTM. VFR CONDITIONS EXPECTED TO CONTINUE OUTSIDE OF SHOWER/TSTM ACTIVITY...WHILE MVFR CIGS AND VSBY WILL BE POSSIBLE IN AND NEAR SHOWERS/TSTMS. PRECIP COVERAGE EXPECTED TO DIMINISH AFT 04Z THIS EVENING WITH VFR CONDITIONS EXPECTED MOST LOCATIONS OVERNIGHT. HOWEVER WITH LITTLE CHANGE IN DWPTS AND PARTIAL CLEARING...FORECAST SOUNDINGS HINT AT SOME PATCHY FOG...PARTICULARLY NEAR AND NORTH OF KRDU. LOOKING BEYOND 12Z TONIGHT: VFR CONDITIONS SHOULD DOMINATE INTO SATURDAY MORNING WITH HIGH PRESSURE STRETCHING OVER THE SOUTHEAST UNITED STATES. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF SUB-VFR CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...NP/HARTFIELD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...NP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
358 PM CDT WED MAY 8 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 358 PM CDT WED MAY 8 2013 THE MAIN FOCUS FOR THE REST OF THIS AFTERNOON AND EVENING WILL BE THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHEAST. THE MAIN FOCUS FOR TONIGHT AND TOMORROW WILL BE THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS IN THE WEST. A COLD FRONT WAS SLOWLY PUSHING SOUTH THIS AFTERNOON ACROSS FAR SOUTHERN NORTH DAKOTA. THE COLD FRONT WILL BE THE PRIMARY LOCATION OF ANY SHOWERS OR THUNDERSTORMS THAT DO DEVELOP. AHEAD OF THE FRONT THE ATMOSPHERE CONTINUES TO DESTABILIZE AS EVIDENCED BY THE CU FIELD IN VISIBLE SATELLITE. THE 17 UTC RAP PAINTS 400+ J/KG OF CAPE ACROSS SOUTHERN NORTH DAKOTA. THE 15 UTC HRRR MODEL HAS SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ALONG AND AHEAD OF THE FRONT LATER THIS AFTERNOON. ONE OF THE MAIN LIMITING FACTORS ON WHETHER SHOWERS AND THUNDERSTORMS DEVELOP AND HOW WIDESPREAD THEY BECOME IS THE BROAD SYNOPTIC SCALE SUBSIDENCE BEHIND THE DEPARTING UPPER LEVEL LOW. LATE TONIGHT AND TOMORROW MORNING A WEAK UPPER LEVEL SHORTWAVE TROUGH WILL ENTER EASTERN MONTANA AND WESTERN NORTH DAKOTA. THIS SHORTWAVE MAY PROVIDE ENOUGH ASCENT ALONG A DEVELOPING SURFACE BAROCLINIC ZONE IN EASTERN MONTANA AND WESTERN NORTH DAKOTA TO SPARK SOME ISOLATED RAIN SHOWERS. SURFACE HIGH PRESSURE AND COLD AIR ADVECTION SHOULD KEEP CENTRAL AND EASTERN NORTH DAKOTA DRY. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 358 PM CDT WED MAY 8 2013 THE MAIN FOCUS OF THE EXTENDED PERIOD WILL BE THE COLD FRONT THAT IS PROGGED TO DROP SOUTH OUT OF SOUTHERN CANADA AND INTO THE NORTHWEST BY FRIDAY MORNING. THIS FRONT WILL CONTINUE TO MOVE SOUTH OVER THE AREA...WITH IT MOVING INTO SOUTH DAKOTA BY EARLY SATURDAY MORNING. THE CONCERN WILL LIE AHEAD OF THIS FRONT...WHERE THUNDERSTORMS MAY BE POSSIBLE. ACCORDING TO THE 12Z NAM...SURFACE BASED CAPE AHEAD OF THIS FRONT WILL BE IN THE 500 TO 600 J/KG RANGE...WITH THE 0-6 KM BULK SHEAR BEING MORE THAN SUFFICIENT FOR AIDING IN THE DEVELOPMENT OF SEVERE THUNDERSTORMS. ON THE OTHER HAND...THE GFS DEPICTS THE STRONG 0-6 KM BULK SHEAR...BUT DOES NOT PAINT ANY SURFACE BASED CAPE NOR MOST UNSTABLE CAPE OVER THE AREA. MOISTURE WILL ALSO BE A LIMITING FACTOR AS FORECAST DEWPOINTS WILL ONLY BE IN THE 30S AND 40S. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD SHOWER ACTIVITY AHEAD OF THE FRONT AND THAT IF ANY THUNDERSTORMS THAT DO DEVELOP WILL REMAIN BELOW THE SEVERE THRESHOLD AND WILL BE OF THE GARDEN VARIETY TYPE. AHEAD OF THE AFOREMENTIONED COLD FRONT...TEMPERATURES WILL WARM WITH THE RETURN FLOW AND BE IN THE 60S AND LOWER 70S. AS THE FRONT MOVES THROUGH THE AREA...TEMPERATURES WILL RETURN TO BELOW NORMAL...WITH TEMPERATURES IN THE UPPER 40S TO MID 50S. SATURDAY NIGHT AND INTO SUNDAY MORNING...THERE IS THE POTENTIAL FOR TEMPERATURES TO FLIRT WITH THE FREEZING MARK ACROSS MOST OF THE AREA AND POSSIBLY ENDANGER NEW VEGETATION AND PLANT GROWTH. THEREAFTER...TEMPERATURES WILL AGAIN WARM SUNDAY AS A WARM FRONT MOVES EAST AND AN UPPER LEVEL RIDGE BUILDS EAST OVER THE NORTHERN PLAINS. TEMPERATURES WILL CLIMB ABOVE NORMAL MONDAY WITH HIGHS IN THE LOW TO MID 80S AS THE RIDGE AXIS MOVES OVERHEAD. FOR THE REMAINDER OF THE PERIOD (TUESDAY ONWARDS)...QUASIZONAL FLOW WILL DEVELOP AND TEMPERATURES WILL RETURN TO SEASONAL NORMS. THERE IS A POSSIBILITY FOR SHOWERS AND THUNDERSTORMS DURING MONDAY EVENING...HOWEVER THEY ARE NOT EXPECTED TO BECOME SEVERE. SHOWERS WILL CONTINUE THROUGH EARLY THURSDAY MORNING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 358 PM CDT WED MAY 8 2013 VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT ALL TERMINALS. GUSTY NORTHEAST WINDS UP TO 22 KNOTS WILL CONTINUE THROUGH AFTERNOON AND EARLY EVENING...DIMINISHING OVER THE NORTHWEST AFTER SUNSET AND AFTER 06Z AT KJMS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AJ LONG TERM...LTH AVIATION...AJ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
333 PM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LEVEL LOW WILL DRIFT TO THE NORTHEAST...REACHING SOUTHERN NEW YORK BY THURSDAY. WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THURSDAY AFTERNOON INTO EARLY FRIDAY. MILDER...AND MORE HUMID AIR WILL PUSH INTO THE REGION FRIDAY AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD FRONT THAT WILL BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN THE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... A SPRAWLING UPPER LOW NEAR STAUNTON VA AROUND MID DAY...WILL CONTINUE TO MOVE NORTHEAST TODAY...KEEPING THE WEATHER CONDITIONS UNSETTLED AND EVEN A LITTLE HUMID. THE AXIS OF ANOMALOUS EASTERLY LOW LEVEL FLOW AND HIGH PWAT AIR WILL LIFT INTO NORTHERN PA AND SOUTHERN NY AS THE DAY PROGRESSES. FOR THE NEXT FEW HOURS HOWEVER...THE BEST MOISTURE AND FORCING WILL CONTINUE TO BE ASSOCIATED WITH THE CLUSTER OF SHOWERS AND STORMS MOVING WNW THROUGH THE MIDDLE AND UPPER SUSQ VALLEY TWD THE NORTHERN MOUNTAINS...A BIT SOUTH OF WHERE THE RUC13 HAS ITS AXIS OF QPF FOR THE NEXT 6 HRS OR SO. HRRR IS SIMILARLY TOO FAR NORTH WITH THE MCS...WHILE THE HIGH-RES ARW DOESN`T SHOW ANY ORGANIZED CONVECTION AT ALL. RADAR ESTIMATES THAT AS MUCH AS AN INCH AN HOUR WAS FALLING UNDER SOME OF THE STRONGER CORES. SEVERE STORMS DO NOT LOOK TO BE A BIG THREAT...MAIN CONCERN WILL BE FOR LOCALLY HEAVY DOWNPOURS. ELSEWHERE OVER ABOUT THE SRN HALF OF THE FCST AREA...SOMEWHAT DRIER AIR AT MID LEVELS IS HELPING DEVELOP BREAKS IN THE CLOUDS WHICH ARE HELPING DESTABILIZE THE ATMOSPHERE...WITH LATEST RAP SHOWING CAPES IN THE 500-1000J RANGE. MID LEVEL LAPSE RATES ARE MARGINALLY STEEP GIVEN THE COLD AIR ALOFT ACCOMPANYING THE UPPER LOW...SO WE WILL STAY VULNERABLE TO ADDITIONAL CONVECTION FIRING UNDER THE STRONG MAY SUNSHINE. ENS MEAN AND OPER QPF INDICATES MAINLY LIGHT QPF AS AN AVERAGE ACROSS THE AREA...A QUARTER INCH OR LESS...BUT OBVIOUSLY THE CONVECTIVE CLUSTER WILL SEE LOCALLY HIGHER AMOUNTS...WITH A HALF INCH OR MORE LIKLEY OVER MUCH OF MY NRN FCST AREA. HIGH TEMPS THIS AFTERNOON WILL VARY FROM THE LOWER 60S ACROSS THE LAURELS AND NW MTNS...TO THE MID AND UPPER 60S ELSEWHERE. PRECIP WILL BECOME MORE SCATTERED TONIGHT AFTER WE LOSE OUR HEATING. THE BEST CHANCES FOR RAIN LOOK LIKE THEY WILL BE OVER THE FAR EAST AND WEST AS THE UPPER LOW MOVES UP AND THROUGH THE REGION. AM MORE CONFIDENT ABOUT WESTERN RAINS AS THIS LOOKS LIKE A GOOD PLACE FOR A DEFORMATION ZONE TO FORM AS THE LOW TRAVERSES THE AREA. TONIGHT`S LOWS WITHIN A COUPLE OF DEGREES EITHER SIDE OF 50 WILL AVERAGE A BIT ABOVE NORMAL. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... THE UPPER LOW WILL BE MOVING INTO NY AND SRN NEW ENGLAND AS THE DAY PROGRESSES THURSDAY. THEORETICALLY WE WILL BE SEEING RISING UPPER HEIGHTS AND EVEN SOME INCREASE IN RIDGING ALOFT APPROACHING FROM THE WEST...BUT SHORT RANGE GUIDANCE IS HINTING AT CONTINUED INSTABILITY SHOWERS...ESPECIALLY AS THE DAY WARMS UP. ALSO THERE IS THE HINT OF PERHAPS SOME LOCALLY MORE ORGANIZED RAINS DEVELOPING OVER NWRN AREAS AS A DEFORMATION ZONE POSSIBLY TRIES TO ORGANIZE IN THE NW QUADRANT OF THE UPPER LOW. THAT IS JUST A PATTERN RECOGNITION THING AT THIS RANGE...WITH ONLY THE OPERATIONAL NAM SUGGESTING ANYTHING MORE THAN SCATTERED SHOWERS THROUGH 18Z. WITH A MIX OF SUN AND CLOUDS WE SHOULD EASILY WARM INTO THE 60S TO LOWER 70S. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... LEFT THU NIGHT MAINL DRY...AS WEAK RIDGING PREVAILS. DID UP TEMPS ON FRIDAY...GIVEN SW FLOW. IN SLIGHT RISK FOR STRONG TO SEVERE STORMS...SOMETHING TO WATCH...GIVEN FCST MAX TEMPS. NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT. SERIES OF COLD FRONTS MOVE ACROSS. ONE FRONT EARLY SAT...THEN ANOTHER SATURDAY NIGHT. THE REAL COLD AIR WILL COME IN LATER SUNDAY...BEHIND THE UPPER LVL FRONT. NEAR RECORD COLD LIKELY FROM LATE SUNDAY INTO TUE AM. FROST AND FREEZE ISSUES WILL BE LIKELY. AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A STRONG WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU... BEFORE ANOTHER COLD SPELL LATER IN THE WEEK. PATERN SUPPORT STRONG TO SEVERE STORMS POSSIBLE WITH WARM FRONT...DID PUT LOW POPS IN ALONG THE NY BORDER. DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT... BUT COULD SEE SOME MID 80S. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... A LOW PRESSURE SYSTEM CURRENTLY OVER WEST VIRGINIA WILL CONTINUE TO SLOWLY SPIN NORTH TODAY. AS THE SYSTEM PULLS ATLANTIC MOISTURE THROUGH PENNSYLVANIA... WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE FROM KIPT TO KBFD THROUGHOUT THE AFTERNOON HOURS. OTHER TERMINALS WILL SEE SCATTERED SHOWERS AND A RUMBLE OR TWO OF THUNDER. SHOWERS WILL DECREASE OVERNIGHT AS THE LOW MOVES NORTH BUT THE LIKELIHOOD OF FOG INCREASES AFTER 06Z. EXPECT MVFR/IFR...WITH SOME SITES POTENTIALLY REACHING LIFR... VSBYS THURSDAY MORNING. WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THURSDAY AFTERNOON INTO EARLY FRIDAY...BRINGING MOSTLY VFR FLYING CONDITIONS. .OUTLOOK... THU...WIDESPREAD MVFR/IFR IN MORNING FOG. THEN MAINLY VFR CONDITIONS WITH MVFR SCATTERED SHOWERS AND ISOLATED TSTMS. FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS. SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT. SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/MARTIN NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...MARTIN AVIATION...LA CORTE/COLBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
151 PM EDT WED MAY 8 2013 .SYNOPSIS... AN UPPER LEVEL LOW WILL DRIFT TO THE NORTHEAST...REACHING SOUTHERN NEW YORK BY THURSDAY. WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THURSDAY AFTERNOON INTO EARLY FRIDAY. MILDER...AND MORE HUMID AIR WILL PUSH INTO THE REGION FRIDAY AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD FRONT THAT WILL BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... A SPRAWLING UPPER LOW NEAR STAUNTON VA AROUND MID DAY...WILL CONTINUE TO MOVE NORTHEAST TODAY...KEEPING THE WEATHER CONDITIONS UNSETTLED AND EVEN A LITTLE HUMID. THE AXIS OF ANOMALOUS EASTERLY LOW LEVEL FLOW AND HIGH PWAT AIR WILL LIFT INTO NORTHERN PA AND SOUTHERN NY AS THE DAY PROGRESSES. FOR THE NEXT FEW HOURS HOWEVER...THE BEST MOISTURE AND FORCING WILL CONTINUE TO BE ASSOCIATED WITH THE CLUSTER OF SHOWERS AND STORMS MOVING WNW THROUGH THE MIDDLE AND UPPER SUSQ VALLEY TWD THE NORTHERN MOUNTAINS...A BIT SOUTH OF WHERE THE RUC13 HAS ITS AXIS OF QPF FOR THE NEXT 6 HRS OR SO. HRRR IS SIMILARLY TOO FAR NORTH WITH THE MCS...WHILE THE HIGH-RES ARW DOESN`T SHOW ANY ORGANIZED CONVECTION AT ALL. RADAR ESTIMATES THAT AS MUCH AS AN INCH AN HOUR WAS FALLING UNDER SOME OF THE STRONGER CORES. SEVERE STORMS DO NOT LOOK TO BE A BIG THREAT...MAIN CONCERN WILL BE FOR LOCALLY HEAVY DOWNPOURS. ELSEWHERE OVER ABOUT THE SRN HALF OF THE FCST AREA...SOMEWHAT DRIER AIR AT MID LEVELS IS HELPING DEVELOP BREAKS IN THE CLOUDS WHICH ARE HELPING DESTABILIZE THE ATMOSPHERE...WITH LATEST RAP SHOWING CAPES IN THE 500-1000J RANGE. MID LEVEL LAPSE RATES ARE MARGINALLY STEEP GIVEN THE COLD AIR ALOFT ACCOMPANYING THE UPPER LOW...SO WE WILL STAY VULNERABLE TO ADDITIONAL CONVECTION FIRING UNDER THE STRONG MAY SUNSHINE. ENS MEAN AND OPER QPF INDICATES MAINLY LIGHT QPF AS AN AVERAGE ACROSS THE AREA...A QUARTER INCH OR LESS...BUT OBVIOUSLY THE CONVECTIVE CLUSTER WILL SEE LOCALLY HIGHER AMOUNTS...WITH A HALF INCH OR MORE LIKLEY OVER MUCH OF MY NRN FCST AREA. HIGH TEMPS THIS AFTERNOON WILL VARY FROM THE LOWER 60S ACROSS THE LAURELS AND NW MTNS...TO THE MID AND UPPER 60S ELSEWHERE. PRECIP WILL BECOME MORE SCATTERED TONIGHT AFTER WE LOSE OUR HEATING. THE BEST CHANCES FOR RAIN LOOK LIKE THEY WILL BE OVER THE FAR EAST AND WEST AS THE UPPER LOW MOVES UP AND THROUGH THE REGION. AM MORE CONFIDENT ABOUT WESTERN RAINS AS THIS LOOKS LIKE A GOOD PLACE FOR A DEFORMATION ZONE TO FORM AS THE LOW TRAVERSES THE AREA. TONIGHT`S LOWS WITHIN A COUPLE OF DEGREES EITHER SIDE OF 50 WILL AVERAGE A BIT ABOVE NORMAL. && .SHORT TERM /THURSDAY/... THE UPPER LOW WILL BE MOVING INTO NY AND SRN NEW ENGLAND AS THE DAY PROGRESSES THURSDAY. THEORETICALLY WE WILL BE SEEING RISING UPPER HEIGHTS AND EVEN SOME INCREASE IN RIDGING ALOFT APPROACHING FROM THE WEST...BUT SHORT RANGE GUIDANCE IS HINTING AT CONTINUED INSTABILITY SHOWERS...ESPECIALLY AS THE DAY WARMS UP. ALSO THERE IS THE HINT OF PERHAPS SOME LOCALLY MORE ORGANIZED RAINS DEVELOPING OVER NWRN AREAS AS A DEFORMATION ZONE POSSIBLY TRIES TO ORGANIZE IN THE NW QUADRANT OF THE UPPER LOW. THAT IS JUST A PATTERN RECOGNITION THING AT THIS RANGE...WITH ONLY THE OPERATIONAL NAM SUGGESTING ANYTHING MORE THAN SCATTERED SHOWERS THROUGH 18Z. WITH A MIX OF SUN AND CLOUDS WE SHOULD EASILY WARM INTO THE 60S TO LOWER 70S. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... MINOR CHANGES MADE FOR THE MOST PART. THE UPPER LVL LOW WILL HAVE TO TRACK TO THE NORTH OF EAST...BEFORE MOVING AWAY FROM THE AREA LATE IN THE WEEK. MOST OF THU NIGHT AND FRIDAY DOES NOT LOOK BAD. IT COULD BE ON THE WARM SIDE FRIDAY...AS NEXT COLD FRONT DROPS SLOWLY SE AND WEAKENS. DID EDGE POPS UP SOME. A MUCH STRONGER COLD FRONT MOVES INTO THE AREA LATE SATURDAY AND EARLY SUNDAY...FOLLOWED BY A SECONDARY FRONT. EXPECT SHOWERS ASSOCIATED WITH THE CFRONT TO BE EAST OF THE AREA BY SUNDAY AFT. HOWEVER...THE MUCH COLDER AIR /-2 TO -3 SIGMA AT 850 MB ACROSS WRN PENN BY 12Z MONDAY/ PLOWING INTO THE REGION FOR LATER SUNDAY INTO EARLY NEXT WEEK...WILL PICK UP MOISTURE FROM THE GLAKES AND LIFT IT ACROSS THE ALLEGHENIES. THIS WILL MAINTAIN PLENTY OF CLOUDS AND SCATTERED RAIN SHOWERS FOR THE NRN AND WRN MTNS OF PA. 925 MB TEMPS OF -1 TO -3C...AND 850 MB TEMPS OF -5 OT -7C WILL BE COLD ENOUGH TO SUPPORT AT LEAST A MIX OF WET SNOW WITH ANY OF THE SHOWERS ACROSS THE HIGHER TERRAIN /AOA 1500 FT MSL/. FROST...FREEZE FLAGS MAY BE NEEDED FOR SUNDAY NIGHT AND MONDAY NIGHT FOR WHAT LOOKS BE NEAR RECORD...OR RECORD COLD. BY MID TO LATE WEEK...IT COULD BE ON THE WARM SIDE...WITH TEMPS IN THE 70S IF NOT 80S...AS THE HIGH MOVES SE...AND WINDS SHIFT TO THE SW. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/... A LOW PRESSURE SYSTEM CURRENTLY OVER WEST VIRGINIA WILL CONTINUE TO SLOWLY SPIN NORTH TODAY. AS THE SYSTEM PULLS ATLANTIC MOISTURE THROUGH PENNSYLVANIA... WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE FROM KIPT TO KBFD THROUGHOUT THE AFTERNOON HOURS. OTHER TERMINALS WILL SEE SCATTERED SHOWERS AND A RUMBLE OR TWO OF THUNDER. SHOWERS WILL DECREASE OVERNIGHT AS THE LOW MOVES NORTH BUT THE LIKELIHOOD OF FOG INCREASES AFTER 06Z. EXPECT MVFR/IFR...WITH SOME SITES POTENTIALLY REACHING LIFR... VSBYS THURSDAY MORNING. WEAK HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THURSDAY AFTERNOON INTO EARLY FRIDAY...BRINGING MOSTLY VFR FLYING CONDITIONS. .OUTLOOK... THU...WIDESPREAD MVFR/IFR IN MORNING FOG. THEN MAINLY VFR CONDITIONS WITH MVFR SCATTERED SHOWERS AND ISOLATED TSTMS. FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS. SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT. SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/MARTIN AVIATION...LA CORTE/COLBERT
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
113 PM CDT WED MAY 8 2013 .AVIATION... FOR THE 18Z TAFS...TIMING THE ONSET OF MVFR STRATUS TONIGHT AND THEN THUNDERSTORM CHANCES OVER THE NEXT 24 TO 30 HRS ARE THE PRIMARY FORECAST CONCERNS. STRATUS...ASIDE FROM THE STRATUS THAT WAS WITHIN 5 MILES OF KACT AT THE TIME OF THIS DISCUSSION...STRATUS IS EXPECTED TO SURGE NORTH THROUGH ALL AREA TAF SITES AFTER MIDNIGHT TONIGHT. FOR THE KACT STRATUS...THE EASTERN EDGE OF THE STRATUS DECK WAS SHOWING SIGNS OF ERODING AT THE TIME OF THIS DISCUSSION...SO DESPITE ITS VERY CLOSE PROXIMITY TO THE AIRPORT WILL NOT CARRY A CIG TO START OFF THE TAFS THERE. OTHERWISE...MOST GUIDANCE INDICATES A RETURN OF STRATUS AFTER MIDNIGHT TONIGHT...WITH MVFR STRATUS MOVING OVER KACT BY 07Z AND THEN OVER THE METROPLEX AREA TAF SITES BY 09Z. MVFR STRATUS WILL LIKELY HOLD UNTIL 17Z WHEN DAYTIME HEATING WILL HELP LIFT CIGS TO VFR LEVELS. THUNDERSTORM CHANCES...STORMS ARE LIKELY TO DEVELOP ALONG THE DRYLINE FROM WESTERN OK SOUTH THRU THE SOUTHERN TX PANHANDLE THIS AFTERNOON. THESE STORMS WILL LIKELY MOVE NORTHEAST THROUGH THIS EVENING AND MAY GROW UPSCALE INTO A LINE WHILE CONTINUING EAST TOWARDS NORTH TX. AT THIS TIME CONFIDENCE IS FAIRLY HIGH THAT THIS EVENING AND OVERNIGHT THUNDERSTORM ACTIVITY WILL REMAIN TOO FAR NORTH OF DFW AREA TAF SITES TO HAVE ANY DIRECT IMPACT ON OPERATIONS. THE DRYLINE IS EXPECTED TO MOVE MUCH FURTHER EAST BY THURSDAY AFTERNOON WHICH MAY CAUSE THUNDERSTORMS TO DEVELOP JUST TO THE WEST OF THE DFW AREA TAF SITES DURING THE PEAK HEATING HRS OF THE DAY. FOR NOW WENT AHEAD WITH A MENTION OF VCTS IN THE EXTENDED PORTION OF THE DFW AREA TAF TO ACCOUNT FOR THIS POSSIBILITY. GUIDANCE INDICATES THAT THUNDERSTORMS COULD DEVELOP IN A BROAD WARM AIR ADVECTION REGIME BY THE EARLY AFTERNOON HRS SOUTHEAST OF THE DFW AREA AND JUST EAST OF KACT. CONFIDENCE IS HIGHER IN DRYLINE INITIATED STORMS THAN WARM AIR ADVECTION INITIATED STORMS AT THIS TIME...SO DID NOT ACCOUNT FOR EARLIER STORM INITIATION TO THE SOUTHEAST OF THE DFW AREA WITH THIS FORECAST. CAVANAUGH && .UPDATE... THE MCV CURRENTLY CENTERED OVER DENTON COUNTY WILL GRADUALLY WEAKEN AS IT PROPAGATES EAST ACROSS NORTH TEXAS. AREAS OF LIGHT PRECIPITATION WITH THE OCCASIONAL LIGHTNING STRIKE CAN BE EXPECTED EAST OF THIS FEATURE THROUGH EARLY AFTERNOON. WENT AHEAD AND EXTENDED THE ISOLATED THUNDER OVER THE NORTHEASTERN HALF OF NORTH TEXAS FOR A FEW HOURS BASED ON THE LATEST RADAR AND SATELLITE TRENDS...OTHERWISE NO SIGNIFICANT CHANGES ARE PLANNED THIS MORNING. 30 && .PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/ AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR THIS ACTIVITY. LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z. MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN THREAT WITH THUNDERSTORMS THROUGH THIS EVENING. THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA. THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON. HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF THE AREA. BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT WEEK. TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS THROUGH THE NEXT 7 DAYS. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20 WACO, TX 86 63 83 64 83 / 10 10 50 70 30 PARIS, TX 85 59 79 62 79 / 10 10 30 50 20 DENTON, TX 85 63 83 62 80 / 10 10 40 60 20 MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20 DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20 TERRELL, TX 85 62 81 63 82 / 10 10 40 60 30 CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30 TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30 MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /