Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/19/12


AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
900 PM EDT FRI MAY 18 2012 .UPDATE (TONIGHT)... 01Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS THE SOUTHEASTERN STATES REMAIN UNDER CONTROL OF UPPER LEVEL TROUGHING ANCHORED BY A CLOSED LOW FEATURE SPINNING NEAR THE CAROLINA COAST. WV IMAGERY SHOWS THAT THE DEEP LAYER WESTERLY FLOW ON THE SOUTHERN SIDE OF THIS CIRCULATION IS SUPPLYING THE REGION WITH A CONTINUOUS INFLUX OF DRY MID/UPPER LEVEL AIR FROM OVER THE GULF OF MEXICO. THIS AIRMASS ABOVE OUR HEADS IS SAMPLED WELL IN THE 19/00Z KTBW SOUNDING PROFILE WHICH SHOWS DEWPOINT DEPRESSIONS EXCEEDING 40C ABOVE 650MB. THETA-E VALUES IN THE 700 TO 500MB LAYER ARE ALSO BETWEEN 316-320K THIS EVENING. THESE FACTORS ARE QUITE HOSTILE TO DEEP CONVECTION...AND IF IT WAS NOT FOR THE UPPER LEVEL FORCING ASSOCIATED WITH THE LATE SEASON TROUGH...IT IS DOUBTFUL THAT WE WOULD EVEN BE ABLE TO SUSTAIN THE FEW STORMS WHICH HAVE FOUGHT THROUGH THE DRY AIR OVER OUR INTERIOR COUNTIES THE PAST SEVERAL HOURS. SO...IT IS TOUGH TO REALLY CLASSIFY THIS ACTIVITY AS TRUE "SEA-BREEZE CONVECTION"...ALTHOUGH THE LOW LEVEL FOCUS OF THE SEA-BREEZE AIDED THE INITIAL ASCENT. HAVE INCREASED THE POPS TO AROUND 30% OVER THE INTERIOR FOR THE NEXT COUPLE OF HOURS TO REPRESENT THE ONGOING ACTIVITY...AND THE LIKELIHOOD THAT IT WILL PERSIST THROUGH 03-04Z DUE TO THE SYNOPTIC FORCING. AFTER THIS TIME...EXPECT ANY LINGERING CONVECTION TO FADE AND LEAVE US WITH A QUIET AND SEASONABLE OVERNIGHT PERIOD. RAIN CHANCES WILL FALL TO 10% OR LESS OVER THE ENTIRE FORECAST AREA AFTER MIDNIGHT THROUGH THE MORNING HOURS OF SATURDAY. && .PREVIOUS DISCUSSION (SATURDAY THROUGH SUNDAY)... IN THE SHORT TERM THE MAIN WEATHER FEATURE ACROSS THE AREA WILL REMAIN THE TROUGH ACROSS THE SOUTHEASTERN STATES. AT 500 MB A LOW WILL BE CUTTING OFF TONIGHT AND INTO THE WEEKEND OFF THE NORTH CAROLINA COAST. THE LOW WILL MAINTAIN A NEARLY STATIONARY POSITION AND SPIN IN PLACE THROUGH THE REMAINDER OF THE WEEKEND. THE SURFACE PATTERN WILL REFLECT THIS UPPER LEVEL FEATURE WITH A LOW DEVELOPING IN NEARLY THE SAME PLACE...AND A WEAK SURFACE TROUGH OR FRONTAL BOUNDARY LINGERING ACROSS THE EXTREME NORTHERN PENINSULA. SURFACE OBS THIS AFTERNOON SHOW A DISTINCT NORTH TO NORTHEAST FLOW NORTH OF THE FORECAST AREA WITH LOWER DEWPOINTS AND COOLER TEMPERATURES. A LITTLE OF THE DRIER AIRMASS WILL INCH INTO THE FAR NORTHERN ZONES ON SATURDAY WITH DEWPOINTS FALLING INTO THE UPPER 50S. THIS WILL BRING SOME COOLER NIGHTTIME LOWS INTO THE NORTHERN INTERIOR AREAS BY SATURDAY NIGHT AND SUNDAY BUT ELSEWHERE THERE SHOULD BE LITTLE TO NO AIRMASS CHANGE. DAYTIME TEMPERATURES SHOULD SHOW ONLY MINOR IMPACTS AS THE DRIER AIR MAY BRING LESS CLOUDS...MORE SUN AND BETTER HEATING. RAIN CHANCES WILL CONTINUE TO BE HIGHEST ACROSS THE INTERIOR AREAS GIVEN THE INLAND PROGRESSION OF THE WEST COAST SEA BREEZE. SHADED POPS A LITTLE LOWER ACROSS THE NORTH FOR THE DRY AIRMASS AND NOTICED AN OVERALL DRYING TREND IN MODEL POPS. && .AVIATION... VFR THROUGH MID DAY SATURDAY...THEN SHOWERS AND THUNDERSTORMS POSSIBLE DURING THE AFTERNOON HOURS. && .MARINE... HIGH PRESSURE BUILDING IN FROM THE NORTH WILL SLOWLY TIGHTEN THE LOCAL GRADIENT OVERNIGHT INTO SATURDAY. IN RESPONSE...EXPECT WINDS TO SHIFT TO A MORE EASTERLY DIRECTION WITH A MODEST INCREASE IN SPEED LATER TONIGHT THROUGH THE UPCOMING WEEKEND. AT THIS TIME...WINDS ANDS SEAS ARE EXPECTED TO GENERALLY REMAIN BELOW HEADLINE CRITERIA. && .PRELIMINARY POINT TEMPS/POPS... TPA 71 89 70 90 / 10 20 10 30 FMY 72 91 68 92 / 10 20 20 30 GIF 68 90 68 91 / 20 40 20 30 SRQ 69 87 69 88 / 10 20 10 30 BKV 63 90 64 91 / 10 20 20 30 SPG 73 88 71 89 / 10 20 10 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE...MROCZKA PREVIOUS DISCUSSION...JOHNSON AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
159 PM EDT THU MAY 17 2012 .AVIATION...VFR PREVAILS. THERE HAVE BEEN PERIODS OF MVFR CIGS. HOWEVER, THEY`VE BROKEN UP IN THE PAST HOUR. BIG CHALLENGE IS WITH REGARDS TO CONVECTION. LIKE YESTERDAY, THE AREA IS SHROUDED IN CLOUD COVER AND TEMPERATURES ARE ONLY IN THE LOWER 80S. HOWEVER, THERE IS A SOUTHEAST WIND ALONG THE ATLANTIC COAST SO WE COULD STILL GET CONVERGENCE AND THE DEVELOPMENT OF SHRA/TSRA IN THE NEXT FEW HOURS...SO MAINTAINED TEMPO FOR TSRA. ANY STORMS COULD PRODUCE BRIEF IFR CONDITIONS ALONG WITH STRONG WIND GUSTS, SHOULD THEY DEVELOP. ANY ACTIVITY WHICH DEVELOPS IS EXPECTED TO GRADUALLY WANE THIS EVENING...BUT MAINTAINED VCSH OVERNIGHT. /GREGORIA && .PREV DISCUSSION... /ISSUED 908 AM EDT THU MAY 17 2012/ UPDATE... SOME CHANGES WERE MADE TO THE SHORT TERM FORECAST. THE SHORT TERM WIND FORECAST IS PROBLEMATIC IN THAT THE CONVECTION THAT PASSED THROUGH THE REGION EARLIER THIS MORNING DISRUPTED THE SYNOPTIC FLOW AND THE WINDS ARE CURRENTLY SOMEWHAT VARIABLE. BUT THE CONSENSUS OF THE LATEST GUIDANCE SUGGESTS THAT A SOUTH TO SOUTHWESTERLY FLOW IS LIKELY TO BECOME RE-ESTABLISHED ACROSS THE REGION LATER THIS MORNING OR THIS AFTERNOON. ALSO UPDATED THE MARINE FORECAST TO REFLECT THE SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE ATLANTIC WATERS FROM EARLIER THIS MORNING BUT THE THUNDERSTORM ACTIVITY IS CURRENTLY SUBSIDING. FOR THE FORECAST FOR THE REMAINDER OF THE DAY...WILL LEAVE CURRENT FORECAST FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. ALTHOUGH ACTIVITY HAS SUBSIDED THIS MORNING...SEVERAL SYNOPTIC FACTORS SUGGEST THAT CONVECTION COULD START LATER THIS MORNING OR INTO THE AFTERNOON. THE FACTORS INCLUDE AN UPPER LEVEL JET PASSING THROUGH THE REGION AND LOW LEVEL MASS AND MOISTURE CONVERGENCE CONTINUING ACROSS THE REGION. PLUS RECENT SATELLITE IMAGERY INDICATES SOME AREAS OF CLEARING ACROSS THE PENINSULA WHICH MAY ALLOW SUFFICIENT DAY TIME HEATING TO INITIATE CONVECTION. BUT BEST CHANCES OF CONVECTION IS PROBABLY STILL THE EASTERN HALF OF THE PENINSULA AND THE ADJACENT ATLANTIC WATERS. 60 PREV DISCUSSION... /ISSUED 741 AM EDT THU MAY 17 2012/ AVIATION...VFR WILL PREVAIL WITH EXTENSIVE MID/HIGH LEVEL CLOUDINESS BEHIND DEPARTING CONVECTION NOW OVER THE ATLANTIC. IT WILL TAKE TIME FOR THE AIRMASS TO RECOVER, AND HRRR ACTUALLY DOES NOT SHOW CONVECTION ON THE EAST COAST UNTIL NEAR KPBI BY 4 PM. IT DOES DEVELOP A BROKEN LINE OF CONVECTION LATE THIS AFTERNOON FROM JUST NORTH OF LAKE OKEECHOBEE TO ACROSS LEE COUNTY BEFORE MOVING SLOWLY SE INTO THE AREA. THIS LATE START TO CONVECTION LOOKS REASONABLE, SO HAVE TEMPO TSRA/MVFR FROM 19-23Z FOR ALL EAST COAST TERMINALS AND VCTS FOR KAPF. MAY NEED TO ADD TEMPO THERE SHOULD A BROKEN LINE OF CONVECTION DEVELOP SO WILL MONITOR TRENDS. ANY STORM LATE THIS AFTERNOON/EVENING WILL BE CAPABLE OF PRODUCING BRIEF IFR CONDITIONS ALONG WITH STRONG WIND GUSTS. /GREGORIA PREV DISCUSSION... /ISSUED 330 AM EDT THU MAY 17 2012/ DISCUSSION...S FLA HAS BEEN UNDER THE INFLUENCE OF THE UPPER TROUGH OVER THE E U.S. COAST THAT CURRENTLY EXTENDS SW ACROSS THE SE U.S. INTO THE GULF OF MEX. TODAY AND INTO THE WEEKEND...A CLOSED LOW WILL DEVELOP OVER THE SE U.S./ADJACENT ATLC AND WILL PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK DUE TO THE DEVELOPMENT OF A REX BLOCK AS A STRONG UPPER RIDGE EXTENDS NW OVER NEW ENGLAND FROM THE ALTC HIGH. THIS STOPS THE MOVEMENT OF THE UPPER LOW. BY MIDWEEK NEXT WEEK...LONG RANGE MODELS DIFFER SOME ON THE SCENARIO...BUT A DEEP UPPER TROUGH OVER THE WESTERN U.S. MOVES E WHICH PULLS THE CLOSED LOW N AND ABSORBING THE FORMER SYSTEM. THE GFS INDICATES MULTIPLE SMALL UPPER TROUGHS THAT MAY CROSS FLA WITH THE ECMWF INDICATING A WESTERLY FLOW ALOFT WHICH MAY BRING MINIMAL SHORT WAVES ACROSS THE AREA. SHORT TERM...(TODAY-SATURDAY)...TODAY COULD BE MORE ACTIVE THAN THURSDAY. A 500 MB 40 KT WIND AXIS MOVES NE ACROSS S CENTRAL FLA WITH S FLA IN THE RFQ WITH SOME SPEED DIVERGENCE. WITH E/W COAST SEA BREEZES DEVELOPING ALONG WITH THE AMPLE POSSIBILITY OF MORE INSOLATION...VERY HIGH POPS WITH NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS POSSIBLE INTERIOR AND E. THERE WILL BE MAINLY EVENING SHOWERS/THUNDERSTORMS E THIS EVENING BUT WITH THE MOIST SW FLOW...ACTIVITY WILL STILL MOVE FROM THE GULF ACROSS THE PENINSULA. POPS DIFFER BETWEEN MODELS FRIDAY BUT THE SURFACE TROUGH...WHICH IS A REFLECTION OF THE UPPER TROUGH TO THE NW...REMAINS NW OF S FLA AND S FLA REMAINS UNDER THE VERY MOIST REGIME LIKE TODAY. THUS...WILL GO ABOVE MAV POPS. FRIDAY NIGHT A SW FLOW ALOFT REMAINS BUT WITH THE SURFACE TROUGH DRAGGING THROUGH...POPS LOWER. ON SATURDAY...SOME DRYING OCCURS. EXTENDED PERIOD...(SUNDAY-WEDNESDAY)...AS MENTIONED ABOVE...THE LONG RANGE PATTERN VARIES PER MODEL AND SOME DECREASE IN CONFIDENCE OF THE POSSIBILITIES EXISTS. WITH THE SW UPPER FLOW PROJECTED TO PERSIST...SOME RIPPLES MOVING THROUGH AND WITH VARIATION ON MODEL PRECIPITATION FORECAST...WILL FOLLOW MEX GUIDANCE BUT EXPECT MORE ACTIVITY IN THE INTERIOR AND NE THROUGH THE PERIOD AS THE LOW LEVEL EASTERLY FLOW EXPECTED SHUNTING PRECIPITATION A BIT TO THE N. MARINE... WINDS GENERALLY LESS THAN 10 KNOTS WITH AND SEAS 3 FEET OR LESS. THE MAIN PROBLEMS WILL BE THE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. FIRE WEATHER... AMPLE RAIN AND HIGH HUMIDITY EQUAL NO PROBLEMS TODAY AND THROUGH THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 84 72 86 72 / 70 50 50 40 FORT LAUDERDALE 85 74 87 75 / 70 50 50 40 MIAMI 85 73 88 74 / 70 50 50 40 NAPLES 83 71 85 70 / 50 50 50 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
940 AM EDT THU MAY 17 2012 .DISCUSSION... CURRENTLY...WEAK SURFACE TROUGH EXTENDS NNE FROM THE YUCATAN TO APALACHEE BAY AND INTO SE GA WITH BROAD MID/UPPER TROUGH COVERING THE NRN GOMEX. RUC INIT PANELS 80-90KT H25 JET CORE PUNCHING OVER THE TOP OF THE STATE WITH BEST DIVG HAVING SHIFTED EAST..AND NOW EXTENDS FROM SOUTH FL NEWD ACROSS THE BAHAMAS AND INTO THE ATLC. VISIBLE SAT IMAGERY SHOWS EXTENSIVE MULTI-LAYERED CLOUDS COVERING THE CWA FROM OSCEOLA/BREVARD SWD...WITH SOME OCNL BREAKS DEVELOPING TO THE N/W. SOUNDER/RAOB DATA SHOW PWATS RANGING FROM 1.5" ACROSS THE NORTH TO 1.8" OR SO NEAR LAKE OKEE...WITH H50 TEMPS -10C/-11C AND EVEN COOLER (-14C @JAX) OVER NORTH FL. TODAY...LIGHT S-SW FLOW EXPECTED AGAIN TODAY ON EAST SIDE OF WEAK SURFACE TROUGH. AXIS OF THE MID LEVEL TROUGH WILL SLIDE EWD WITH INCREASING MID LEVEL PVA COUNTERACTING THE EWD SHIFT OF JET FORCED ASCENT AWAY FROM THE PENINSULA TO SOME DEGREE. EXPECT TODAY TO BE MORE CONVECTIVELY ACTIVE OVERALL...WITH EARLIER ONSET COMPARED TO WED. LACK OF WIDESPREAD OVC CLOUD DECK SHOULD ALLOW BETTER SURFACE HEATING AND THUS GREATER INSTABILITY AND STRONGER MORE NUMEROUS AFTERNOON STORMS...WHILE CONTINUATION OF SOME COMPONENT OF FORCED ASCENT WOULD FAVOR ACTIVITY CONTINUING PAST SUNSET FOR AT LEAST A FEW HOURS. CURRENT FCST HAS A GOOD HANDLE ON SITUATION WITH SLIGHTLY HIGHER POP DISTRIBUTION SOUTH. && .AVIATION...MULTILAYERED BROKEN CLOUDS/SHRA SOUTH/EAST OF KTIX-KAGR WITH SOME IFR STRATUS OVER NORTH FL....SWD TO ABOUT KLEE. ISOLATED SHRA/TS STARTING AROUND 16Z. ACTIVITY INCREASING IN COVERAGE AND BECOMING NMRS AFTER 18Z WITH LOCAL IFR CIGS/VSBYS IN STORMS. SOME STORMS MAY PRODUCE WIND GUSTS OVER 35KT THIS AFTERNOON AND EVENING THROUGH ABOUT 02Z-03Z. && .MARINE... TODAY-TONIGHT...PRIMARY MARINE CONCERN CONTINUES TO BE OFFSHORE MOVING THUNDERSTORMS THIS AFTERNOON/EVENING. WINDS REMAIN 10KTS OR LESS OUT OF THE S-SW WITH SEAS 1-2FT NEARSHORE AND 2-3FT OFFSHORE IN A LONG PERIOD SWELL. && .FIRE WEATHER... NO RH/WIND CONCERNS TODAY. NUMEROUS AFTERNOON/EVENING SHRAS/TS. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...CRISTALDI LONG TERM/IMPACT WX...WIMMER
AREA FORECAST DISCUSSION
NWS MIAMI FL
908 AM EDT THU MAY 17 2012 .UPDATE... SOME CHANGES WERE MADE TO THE SHORT TERM FORECAST. THE SHORT TERM WIND FORECAST IS PROBLEMATIC IN THAT THE CONVECTION THAT PASSED THROUGH THE REGION EARLIER THIS MORNING DISRUPTED THE SYNOPTIC FLOW AND THE WINDS ARE CURRENTLY SOMEWHAT VARIABLE. BUT THE CONSENSUS OF THE LATEST GUIDANCE SUGGESTS THAT A SOUTH TO SOUTHWESTERLY FLOW IS LIKELY TO BECOME RE-ESTABLISHED ACROSS THE REGION LATER THIS MORNING OR THIS AFTERNOON. ALSO UPDATED THE MARINE FORECAST TO REFLECT THE SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE ATLANTIC WATERS FROM EARLIER THIS MORNING BUT THE THUNDERSTORM ACTIVITY IS CURRENTLY SUBSIDING. FOR THE FORECAST FOR THE REMAINDER OF THE DAY...WILL LEAVE CURRENT FORECAST FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. ALTHOUGH ACTIVITY HAS SUBSIDED THIS MORNING...SEVERAL SYNOPTIC FACTORS SUGGEST THAT CONVECTION COULD START LATER THIS MORNING OR INTO THE AFTERNOON. THE FACTORS INCLUDE AN UPPER LEVEL JET PASSING THROUGH THE REGION AND LOW LEVEL MASS AND MOISTURE CONVERGENCE CONTINUING ACROSS THE REGION. PLUS RECENT SATELLITE IMAGERY INDICATES SOME AREAS OF CLEARING ACROSS THE PENINSULA WHICH MAY ALLOW SUFFICIENT DAY TIME HEATING TO INITIATE CONVECTION. BUT BEST CHANCES OF CONVECTION IS PROBABLY STILL THE EASTERN HALF OF THE PENINSULA AND THE ADJACENT ATLANTIC WATERS. 60 && .PREV DISCUSSION... /ISSUED 741 AM EDT THU MAY 17 2012/ AVIATION...VFR WILL PREVAIL WITH EXTENSIVE MID/HIGH LEVEL CLOUDINESS BEHIND DEPARTING CONVECTION NOW OVER THE ATLANTIC. IT WILL TAKE TIME FOR THE AIRMASS TO RECOVER, AND HRRR ACTUALLY DOES NOT SHOW CONVECTION ON THE EAST COAST UNTIL NEAR KPBI BY 4 PM. IT DOES DEVELOP A BROKEN LINE OF CONVECTION LATE THIS AFTERNOON FROM JUST NORTH OF LAKE OKEECHOBEE TO ACROSS LEE COUNTY BEFORE MOVING SLOWLY SE INTO THE AREA. THIS LATE START TO CONVECTION LOOKS REASONABLE, SO HAVE TEMPO TSRA/MVFR FROM 19-23Z FOR ALL EAST COAST TERMINALS AND VCTS FOR KAPF. MAY NEED TO ADD TEMPO THERE SHOULD A BROKEN LINE OF CONVECTION DEVELOP SO WILL MONITOR TRENDS. ANY STORM LATE THIS AFTERNOON/EVENING WILL BE CAPABLE OF PRODUCING BRIEF IFR CONDITIONS ALONG WITH STRONG WIND GUSTS. /GREGORIA PREV DISCUSSION... /ISSUED 330 AM EDT THU MAY 17 2012/ DISCUSSION...S FLA HAS BEEN UNDER THE INFLUENCE OF THE UPPER TROUGH OVER THE E U.S. COAST THAT CURRENTLY EXTENDS SW ACROSS THE SE U.S. INTO THE GULF OF MEX. TODAY AND INTO THE WEEKEND...A CLOSED LOW WILL DEVELOP OVER THE SE U.S./ADJACENT ATLC AND WILL PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK DUE TO THE DEVELOPMENT OF A REX BLOCK AS A STRONG UPPER RIDGE EXTENDS NW OVER NEW ENGLAND FROM THE ALTC HIGH. THIS STOPS THE MOVEMENT OF THE UPPER LOW. BY MIDWEEK NEXT WEEK...LONG RANGE MODELS DIFFER SOME ON THE SCENARIO...BUT A DEEP UPPER TROUGH OVER THE WESTERN U.S. MOVES E WHICH PULLS THE CLOSED LOW N AND ABSORBING THE FORMER SYSTEM. THE GFS INDICATES MULTIPLE SMALL UPPER TROUGHS THAT MAY CROSS FLA WITH THE ECMWF INDICATING A WESTERLY FLOW ALOFT WHICH MAY BRING MINIMAL SHORT WAVES ACROSS THE AREA. SHORT TERM...(TODAY-SATURDAY)...TODAY COULD BE MORE ACTIVE THAN THURSDAY. A 500 MB 40 KT WIND AXIS MOVES NE ACROSS S CENTRAL FLA WITH S FLA IN THE RFQ WITH SOME SPEED DIVERGENCE. WITH E/W COAST SEA BREEZES DEVELOPING ALONG WITH THE AMPLE POSSIBILITY OF MORE INSOLATION...VERY HIGH POPS WITH NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS POSSIBLE INTERIOR AND E. THERE WILL BE MAINLY EVENING SHOWERS/THUNDERSTORMS E THIS EVENING BUT WITH THE MOIST SW FLOW...ACTIVITY WILL STILL MOVE FROM THE GULF ACROSS THE PENINSULA. POPS DIFFER BETWEEN MODELS FRIDAY BUT THE SURFACE TROUGH...WHICH IS A REFLECTION OF THE UPPER TROUGH TO THE NW...REMAINS NW OF S FLA AND S FLA REMAINS UNDER THE VERY MOIST REGIME LIKE TODAY. THUS...WILL GO ABOVE MAV POPS. FRIDAY NIGHT A SW FLOW ALOFT REMAINS BUT WITH THE SURFACE TROUGH DRAGGING THROUGH...POPS LOWER. ON SATURDAY...SOME DRYING OCCURS. EXTENDED PERIOD...(SUNDAY-WEDNESDAY)...AS MENTIONED ABOVE...THE LONG RANGE PATTERN VARIES PER MODEL AND SOME DECREASE IN CONFIDENCE OF THE POSSIBILITIES EXISTS. WITH THE SW UPPER FLOW PROJECTED TO PERSIST...SOME RIPPLES MOVING THROUGH AND WITH VARIATION ON MODEL PRECIPITATION FORECAST...WILL FOLLOW MEX GUIDANCE BUT EXPECT MORE ACTIVITY IN THE INTERIOR AND NE THROUGH THE PERIOD AS THE LOW LEVEL EASTERLY FLOW EXPECTED SHUNTING PRECIPITATION A BIT TO THE N. MARINE... WINDS GENERALLY LESS THAN 10 KNOTS WITH AND SEAS 3 FEET OR LESS. THE MAIN PROBLEMS WILL BE THE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. FIRE WEATHER... AMPLE RAIN AND HIGH HUMIDITY EQUAL NO PROBLEMS TODAY AND THROUGH THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 84 72 86 72 / 70 50 50 40 FORT LAUDERDALE 85 74 87 75 / 70 50 50 40 MIAMI 85 73 88 74 / 70 50 50 40 NAPLES 83 71 85 70 / 50 50 50 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...60/BD AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS MIAMI FL
741 AM EDT THU MAY 17 2012 .AVIATION...VFR WILL PREVAIL WITH EXTENSIVE MID/HIGH LEVEL CLOUDINESS BEHIND DEPARTING CONVECTION NOW OVER THE ATLANTIC. IT WILL TAKE TIME FOR THE AIRMASS TO RECOVER, AND HRRR ACTUALLY DOES NOT SHOW CONVECTION ON THE EAST COAST UNTIL NEAR KPBI BY 4 PM. IT DOES DEVELOP A BROKEN LINE OF CONVECTION LATE THIS AFTERNOON FROM JUST NORTH OF LAKE OKEECHOBEE TO ACROSS LEE COUNTY BEFORE MOVING SLOWLY SE INTO THE AREA. THIS LATE START TO CONVECTION LOOKS REASONABLE, SO HAVE TEMPO TSRA/MVFR FROM 19-23Z FOR ALL EAST COAST TERMINALS AND VCTS FOR KAPF. MAY NEED TO ADD TEMPO THERE SHOULD A BROKEN LINE OF CONVECTION DEVELOP SO WILL MONITOR TRENDS. ANY STORM LATE THIS AFTERNOON/EVENING WILL BE CAPABLE OF PRODUCING BRIEF IFR CONDITIONS ALONG WITH STRONG WIND GUSTS. /GREGORIA && .PREV DISCUSSION... /ISSUED 330 AM EDT THU MAY 17 2012/ DISCUSSION...S FLA HAS BEEN UNDER THE INFLUENCE OF THE UPPER TROUGH OVER THE E U.S. COAST THAT CURRENTLY EXTENDS SW ACROSS THE SE U.S. INTO THE GULF OF MEX. TODAY AND INTO THE WEEKEND...A CLOSED LOW WILL DEVELOP OVER THE SE U.S./ADJACENT ATLC AND WILL PERSIST THROUGH THE WEEKEND INTO EARLY NEXT WEEK DUE TO THE DEVELOPMENT OF A REX BLOCK AS A STRONG UPPER RIDGE EXTENDS NW OVER NEW ENGLAND FROM THE ALTC HIGH. THIS STOPS THE MOVEMENT OF THE UPPER LOW. BY MIDWEEK NEXT WEEK...LONG RANGE MODELS DIFFER SOME ON THE SCENARIO...BUT A DEEP UPPER TROUGH OVER THE WESTERN U.S. MOVES E WHICH PULLS THE CLOSED LOW N AND ABSORBING THE FORMER SYSTEM. THE GFS INDICATES MULTIPLE SMALL UPPER TROUGHS THAT MAY CROSS FLA WITH THE ECMWF INDICATING A WESTERLY FLOW ALOFT WHICH MAY BRING MINIMAL SHORT WAVES ACROSS THE AREA. SHORT TERM...(TODAY-SATURDAY)...TODAY COULD BE MORE ACTIVE THAN THURSDAY. A 500 MB 40 KT WIND AXIS MOVES NE ACROSS S CENTRAL FLA WITH S FLA IN THE RFQ WITH SOME SPEED DIVERGENCE. WITH E/W COAST SEA BREEZES DEVELOPING ALONG WITH THE AMPLE POSSIBILITY OF MORE INSOLATION...VERY HIGH POPS WITH NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS POSSIBLE INTERIOR AND E. THERE WILL BE MAINLY EVENING SHOWERS/THUNDERSTORMS E THIS EVENING BUT WITH THE MOIST SW FLOW...ACTIVITY WILL STILL MOVE FROM THE GULF ACROSS THE PENINSULA. POPS DIFFER BETWEEN MODELS FRIDAY BUT THE SURFACE TROUGH...WHICH IS A REFLECTION OF THE UPPER TROUGH TO THE NW...REMAINS NW OF S FLA AND S FLA REMAINS UNDER THE VERY MOIST REGIME LIKE TODAY. THUS...WILL GO ABOVE MAV POPS. FRIDAY NIGHT A SW FLOW ALOFT REMAINS BUT WITH THE SURFACE TROUGH DRAGGING THROUGH...POPS LOWER. ON SATURDAY...SOME DRYING OCCURS. EXTENDED PERIOD...(SUNDAY-WEDNESDAY)...AS MENTIONED ABOVE...THE LONG RANGE PATTERN VARIES PER MODEL AND SOME DECREASE IN CONFIDENCE OF THE POSSIBILITIES EXISTS. WITH THE SW UPPER FLOW PROJECTED TO PERSIST...SOME RIPPLES MOVING THROUGH AND WITH VARIATION ON MODEL PRECIPITATION FORECAST...WILL FOLLOW MEX GUIDANCE BUT EXPECT MORE ACTIVITY IN THE INTERIOR AND NE THROUGH THE PERIOD AS THE LOW LEVEL EASTERLY FLOW EXPECTED SHUNTING PRECIPITATION A BIT TO THE N. MARINE... WINDS GENERALLY LESS THAN 10 KNOTS WITH AND SEAS 3 FEET OR LESS. THE MAIN PROBLEMS WILL BE THE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. FIRE WEATHER... AMPLE RAIN AND HIGH HUMIDITY EQUAL NO PROBLEMS TODAY AND THROUGH THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 84 72 86 72 / 70 50 50 40 FORT LAUDERDALE 85 74 87 75 / 70 50 50 40 MIAMI 85 73 88 74 / 70 50 50 40 NAPLES 83 71 85 70 / 50 50 50 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...15/JR AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
113 PM EDT THU MAY 17 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 140 AM EDT THU MAY 17 2012 HIGH PRESSURE OVER THE APPALACHIANS WILL DOMINATE INDIANA WEATHER THROUGH THE WEEKEND. A COLD FRONT IS FORECAST TO APPROACH AND THEN CROSS THE HOOSIER STATE MONDAY AND TUESDAY. AFTER THAT...HIGH PRESSURE SHOULD RETURN FROM THE WEST. && .NEAR TERM /TODAY/... ISSUED AT 1010 AM EDT THU MAY 17 2012 NO SIGNIFICANT CHANGES NEEDED AT THIS TIME. MADE SOME CHANGES TO THE DEWPOINT GRIDS TO LOWER THEM ACROSS THE SOUTH AS SOME DRY ADVECTION OCCURRING. PREVIOUS FORECAST HAD LEANED TOWARDS WARMER MAV AND THIS SEEMS REASONABLE GIVEN THERE WILL BE FULL SUNSHINE TODAY. THE RUC MODEL SOUNDINGS WERE A LITTLE WARMER WHILE THE 00Z NAM SOUNDINGS WERE A LITTLE COOLER. MADE A FEW MINOR TWEAKS TO TEMPERATURE GRIDS MAINLY TO LOWER THEM A DEGREE IN THE EAST. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 140 AM EDT THU MAY 17 2012 ALL MODELS CLOSE..BUT NAM IS A MINOR OUTLIER COMPARED TO NEARLY IDENTICAL SREF AND GFS. WITH GFS LOOKING A LITTLE BETTER WILL USE THAT AS UNDERLYING MODEL. THIS DOES NOT MAKE MUCH DIFFERENCE SINCE ALL MODELS CALLING FOR MOSTLY CLEAR THROUGH SATURDAY AND MET AND MAV ARE CLOSE ON TEMPS. USING MAV WHEN ANY DIFFERENCE FROM MET BECAUSE FAVOR GFS AND MAV HAD LONGER DEVELOPMENT CYCLE. PRECIP NOT ABSOLUTELY OUT OF QUESTION SATURDAY NIGHT IN WARM ADVECTION. HOWEVER POSSIBILITY IS MARGINAL AT MOST AND WILL CONTINUE WITH DRY FORECAST FOR NOW. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 220 AM EDT THU MAY 17 2012 MAIN FOCUS ON THE LONG TERM WILL BE TIMING OF THUNDERSTORM CHANCES BACK TO CENTRAL INDIANA ALONG WITH TEMPERATURES AS A COLD FRONT APPROACHES LATE IN THE WEEKEND AND EARLY NEXT WEEK. THE 00Z GEM IS NOW LEANING SLOWER WITH A COLD FRONT LATE THIS WEEKEND AND EARLY NEXT WEEK PER THE 12Z ECMWF AND EURO TRENDS AND AS OPPOSED TO THE FASTER 00Z GFS AND GFS TRENDS. THIS WOULD FAVOR HOLDING OFF POPS INTIL SUNDAY NIGHT ACROSS THE WEST AND ACROSS ALL OF CENTRAL INDIANA BY MONDAY. THE FRONT AND ASSOCIATED CONVECTION ARE EXPECTED TO RESULT IN NOT AS WARM TEMPERATURES BY MONDAY WITH REASONABLE CR INIT HIGHS ONLY IN THE 70S BY TUESDAY WITH 80S SUNDAY AND MONDAY AHEAD OF THE FRONT. INSTABILITY PROGS SUGGEST PLENTY OF INSTABILITY THROUGH THE PERIOD FOR THUNDERSTORM MENTION. && .AVIATION /DISCUSSION FOR THE 17/1800Z TAF ISSUANCE/... ISSUED AT 104 PM EDT THU MAY 17 2012 VFR CONDITIONS EXPECTED FOR ENTIRE TAF PERIOD WITH HIGH PRESSURE STILL IN CONTROL OVER TAF SITES. WILL NOT INSERT ANY FOG FOR TONIGHT...MODELS ARE NOT INDICATING ANY FORMATION. WINDS WILL BE EASTERLY AT 4 TO 8 KTS THROUGH THIS EVENING...AND WILL THEN DECREASE TO 2 TO 4 KTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...JK NEAR TERM...JK SHORT TERM...JH LONG TERM....MK AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1043 AM EDT THU MAY 17 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 140 AM EDT THU MAY 17 2012 HIGH PRESSURE OVER THE APPALACHIANS WILL DOMINATE INDIANA WEATHER THROUGH THE WEEKEND. A COLD FRONT IS FORECAST TO APPROACH AND THEN CROSS THE HOOSIER STATE MONDAY AND TUESDAY. AFTER THAT...HIGH PRESSURE SHOULD RETURN FROM THE WEST. && .NEAR TERM /TODAY/... ISSUED AT 1010 AM EDT THU MAY 17 2012 NO SIGNIFICANT CHANGES NEEDED AT THIS TIME. MADE SOME CHANGES TO THE DEWPOINT GRIDS TO LOWER THEM ACROSS THE SOUTH AS SOME DRY ADVECTION OCCURRING. PREVIOUS FORECAST HAD LEANED TOWARDS WARMER MAV AND THIS SEEMS REASONABLE GIVEN THERE WILL BE FULL SUNSHINE TODAY. THE RUC MODEL SOUNDINGS WERE A LITTLE WARMER WHILE THE 00Z NAM SOUNDINGS WERE A LITTLE COOLER. MADE A FEW MINOR TWEAKS TO TEMPERATURE GRIDS MAINLY TO LOWER THEM A DEGREE IN THE EAST. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 140 AM EDT THU MAY 17 2012 ALL MODELS CLOSE..BUT NAM IS A MINOR OUTLIER COMPARED TO NEARLY IDENTICAL SREF AND GFS. WITH GFS LOOKING A LITTLE BETTER WILL USE THAT AS UNDERLYING MODEL. THIS DOES NOT MAKE MUCH DIFFERENCE SINCE ALL MODELS CALLING FOR MOSTLY CLEAR THROUGH SATURDAY AND MET AND MAV ARE CLOSE ON TEMPS. USING MAV WHEN ANY DIFFERENCE FROM MET BECAUSE FAVOR GFS AND MAV HAD LONGER DEVELOPMENT CYCLE. PRECIP NOT ABSOLUTELY OUT OF QUESTION SATURDAY NIGHT IN WARM ADVECTION. HOWEVER POSSIBILITY IS MARGINAL AT MOST AND WILL CONTINUE WITH DRY FORECAST FOR NOW. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 220 AM EDT THU MAY 17 2012 MAIN FOCUS ON THE LONG TERM WILL BE TIMING OF THUNDERSTORM CHANCES BACK TO CENTRAL INDIANA ALONG WITH TEMPERATURES AS A COLD FRONT APPROACHES LATE IN THE WEEKEND AND EARLY NEXT WEEK. THE 00Z GEM IS NOW LEANING SLOWER WITH A COLD FRONT LATE THIS WEEKEND AND EARLY NEXT WEEK PER THE 12Z ECMWF AND EURO TRENDS AND AS OPPOSED TO THE FASTER 00Z GFS AND GFS TRENDS. THIS WOULD FAVOR HOLDING OFF POPS INTIL SUNDAY NIGHT ACROSS THE WEST AND ACROSS ALL OF CENTRAL INDIANA BY MONDAY. THE FRONT AND ASSOCIATED CONVECTION ARE EXPECTED TO RESULT IN NOT AS WARM TEMPERATURES BY MONDAY WITH REASONABLE CR INIT HIGHS ONLY IN THE 70S BY TUESDAY WITH 80S SUNDAY AND MONDAY AHEAD OF THE FRONT. INSTABILITY PROGS SUGGEST PLENTY OF INSTABILITY THROUGH THE PERIOD FOR THUNDERSTORM MENTION. && .AVIATION /DISCUSSION FOR THE 17/1500Z TAF UPDATE/... ISSUED AT 1041 AM EDT THU MAY 17 2012 UPDATE... NO CHANGES. PREVIOUS DISCUSSION... VFR CONDITIONS EXPECTED TODAY WITH JUST SOME HIGH CLOUDS LATE. CU PROGS WERE NOT INDICATING ANY DIURNAL CU. WOULD NOT RULE OUT FOG OVERNIGHT TONIGHT WITH MODELS AGREEING ON DEW POINTS INCREASING TO THE UPPER 40S AS HIGH PRESSURE SHIFTS TO THE EASTERN GREAT LAKES ALLOW FOR LIGHT SOUTHEAST ATLANTIC FETCH OF MOISTURE. HOWEVER...MOS IS NOT INDICATING ANY YET...SO WILL HOLD OFF FOR NOW DESPITE EAST WINDS NEAR 10 KNOTS TODAY BECOMING LIGHT TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...JK NEAR TERM...JK SHORT TERM...JH LONG TERM....MK AVIATION...MK/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1010 AM EDT FRI MAY 17 2012 .UPDATE... NEAR TERM FR THE REST OF TODAY HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 140 AM EDT THU MAY 17 2012 HIGH PRESSURE OVER THE APPALACHIANS WILL DOMINATE INDIANA WEATHER THROUGH THE WEEKEND. A COLD FRONT IS FORECAST TO APPROACH AND THEN CROSS THE HOOSIER STATE MONDAY AND TUESDAY. AFTER THAT...HIGH PRESSURE SHOULD RETURN FROM THE WEST. && .NEAR TERM /TODAY/... ISSUED AT 1010 AM EDT THU MAY 17 2012 NO SIGNIFICANT CHANGES NEEDED AT THIS TIME. MADE SOME CHANGES TO THE DEWPOINT GRIDS TO LOWER THEM ACROSS THE SOUTH AS SOME DRY ADVECTION OCCURRING. PREVIOUS FORECAST HAD LEANED TOWARDS WARMER MAV AND THIS SEEMS REASONABLE GIVEN THERE WILL BE FULL SUNSHINE TODAY. THE RUC MODEL SOUNDINGS WERE A LITTLE WARMER WHILE THE 00Z NAM SOUNDINGS WERE A LITTLE COOLER. MADE A FEW MINOR TWEAKS TO TEMPERATURE GRIDS MAINLY TO LOWER THEM A DEGREE IN THE EAST. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 140 AM EDT THU MAY 17 2012 ALL MODELS CLOSE..BUT NAM IS A MINOR OUTLIER COMPARED TO NEARLY IDENTICAL SREF AND GFS. WITH GFS LOOKING A LITTLE BETTER WILL USE THAT AS UNDERLYING MODEL. THIS DOES NOT MAKE MUCH DIFFERENCE SINCE ALL MODELS CALLING FOR MOSTLY CLEAR THROUGH SATURDAY AND MET AND MAV ARE CLOSE ON TEMPS. USING MAV WHEN ANY DIFFERENCE FROM MET BECAUSE FAVOR GFS AND MAV HAD LONGER DEVELOPMENT CYCLE. PRECIP NOT ABSOLUTELY OUT OF QUESTION SATURDAY NIGHT IN WARM ADVECTION. HOWEVER POSSIBILITY IS MARGINAL AT MOST AND WILL CONTINUE WITH DRY FORECAST FOR NOW. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 220 AM EDT THU MAY 17 2012 MAIN FOCUS ON THE LONG TERM WILL BE TIMING OF THUNDERSTORM CHANCES BACK TO CENTRAL INDIANA ALONG WITH TEMPERATURES AS A COLD FRONT APPROACHES LATE IN THE WEEKEND AND EARLY NEXT WEEK. THE 00Z GEM IS NOW LEANING SLOWER WITH A COLD FRONT LATE THIS WEEKEND AND EARLY NEXT WEEK PER THE 12Z ECMWF AND EURO TRENDS AND AS OPPOSED TO THE FASTER 00Z GFS AND GFS TRENDS. THIS WOULD FAVOR HOLDING OFF POPS INTIL SUNDAY NIGHT ACROSS THE WEST AND ACROSS ALL OF CENTRAL INDIANA BY MONDAY. THE FRONT AND ASSOCIATED CONVECTION ARE EXPECTED TO RESULT IN NOT AS WARM TEMPERATURES BY MONDAY WITH REASONABLE CR INIT HIGHS ONLY IN THE 70S BY TUESDAY WITH 80S SUNDAY AND MONDAY AHEAD OF THE FRONT. INSTABILITY PROGS SUGGEST PLENTY OF INSTABILITY THROUGH THE PERIOD FOR THUNDERSTORM MENTION. && .AVIATION /DISCUSSION FOR 171200Z TAF ISSUANCE/... ISSUED AT 617 AM EDT WED MAY 17 2012 VFR CONDITIONS EXPECTED TODAY WITH JUST SOME HIGH CLOUDS LATE. CU PROGS WERE NOT INDICATING ANY DIURNAL CU. WOULD NOT RULE OUT FOG OVERNIGHT TONIGHT WITH MODELS AGREEING ON DEW POINTS INCREASING TO THE UPPER 40S AS HIGH PRESSURE SHIFTS TO THE EASTERN GREAT LAKES ALLOW FOR LIGHT SOUTHEAST ATLANTIC FETCH OF MOISTURE. HOWEVER...MOS IS NOT INDICATING ANY YET...SO WILL HOLD OFF FOR NOW DESPITE EAST WINDS NEAR 10 KNOTS TODAY BECOMING LIGHT TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JK NEAR TERM...JK SHORT TERM...JH LONG TERM....MK AVIATION...MK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1110 PM MDT WED MAY 16 2012 .UPDATE... ISSUED AT 827 PM MDT WED MAY 16 2012 MAIN UPDATE WAS TO REMOVE THREAT OF THUNDERSTORMS FROM EASTERN COLORADO TONIGHT. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 150 PM MDT WED MAY 16 2012 EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE RIDGE OVER WESTERN KS BEGINNING TO BREAK DOWN AS SHORTWAVE TROUGH OVER GREAT BASIN CONTINUES TO MOVE EAST INTO THE CENTRAL ROCKIES. TIGHT GRADIENT CURRENTLY IN PLACE ACROSS CWA NO EASTERN EXTENT OF LEE TROUGH HAS LED TO BREEZY CONDITIONS ACROSS THE AREA...WITH WINDS GUSTING AROUND 30KT AT SEVERAL LOCATIONS. A WARM FRONT JUST SOUTHWEST OF GOODLAND LIFTING TO THE NORTHEAST. WEST OF THIS FRONT RH VALUES HAVE DROPPED TO 15% OR LOWER. WITH SEVERAL LOCATIONS ALREADY WITHIN RED FLAG CRITERIA...PLAN ON KEEPING RFW IN PLACE THROUGH EXPIRATION (02Z). SHORTWAVE TROUGH WILL CONTINUE TO MOVE EAST WITH LARGE SCALE ASCENT SPREADING INTO EASTERN COLORADO. RADAR RETURNS ALREADY SHOWING SHOWERS/THUNDERSTORMS ALONG FRONT RANGE...WITH ACTIVITY GENERALLY MOVING FROM THE SOUTH TO NORTH. LATEST RUC/HRRR SHOW THIS ACTIVITY REMAINING JUST EAST OF THE CWA. WITH LARGE SCALE ASCENT STILL EXPECTED TO OVERSPREAD THE CWA...AND THE CLOSE PROXIMITY OF ACTIVITY...I DECIDED TO LEAVE ISOLATED THUNDERSTORMS IN FORECAST THIS EVENING. SHORTWAVE TROUGH AXIS CURRENTLY PROGGED TO MOVE EAST ACROSS WESTERN KS. GUIDANCE IN GENERAL AGREEMENT ON TIMING...HOWEVER STRENGTH AND POSITION OF SHORTWAVE ARE STILL ISSUES...WITH KEEPING OUR CWA DRY...AND OTHER GUIDANCE FAVORING THE SOUTH AND EAST LATE THURSDAY AFTERNOON. WITH INSTABILITY/LARGE SCALE ASCENT ACROSS THE CWA THURSDAY...SLIGHT CHANCE POPS FROM PREVIOUS FORECAST SEEMED REASONABLE. TIGHT SURFACE GRADIENT WILL REMAIN IN PLACE OVER EASTERN PARTS OF CWA...WITH NAM/GFS BL WINDS APPROACHING ADVISORY CRITERIA FOR A PERIOD OF TIME THURSDAY AFTERNOON. CONFIDENCE IS NOT THERE THAT ADVISORY CRITERIA WINDS WILL LAST 3HR...SO NO HAZARD PLANNED. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 248 PM MDT WED MAY 16 2012 THURSDAY EVENING THE SHORT WAVE TROUGH WILL CONTINUE TO MOVE EAST ACROSS THE AREA. LATEST GUIDANCE DISAGREES WITH THE LOCATION OF THE SHORT WAVE TROUGH DURING THE EVENING...WITH THE GFS SHIFTING THE TROUGH FURTHER NORTH WHILE THE NAM HAS KEPT THE TROUGH OVER THE SOUTHERN PART OF THE AREA. WITH MODELS NOT BEING CONSISTENT WITH THE PLACEMENT OF THE SHORT WAVE TROUGH...WILL EXPAND THE SLIGHT CHANCES TO INCLUDE THE ENTIRE AREA EAST OF THE COLORADO LINE. WITH A DEEP WELL MIXED LAYER IN PLACE OVER THE AREA...STRONG DOWN BURST WINDS WILL BE POSSIBLE WITH ANY THUNDERSTORM THAT DEVELOPS DURING THE EARLY EVENING. THE SHORT WAVE TROUGH AND MID LEVEL CAPE WILL EXIT THE AREA AROUND MIDNIGHT BRINGING ANY CHANCE FOR PRECIPITATION TO AN END. FRIDAY A DRY LINE SETS UP OVER THE CENTRAL PART OF THE AREA. DURING THE MID TO LATE AFTERNOON A SHORT WAVE TROUGH MOVES OVER THE DRY LINE. POINT SOUNDINGS FOR THE AREA SHOW THE ENVIRONMENT NEARING SATURATION AROUND THE 500MB LEVEL ON UP...SO AM THINKING THE STORM DEVELOPMENT WILL BE TIED TO THE LOCATION OF THE 500MB LIFT. HOWEVER CANNOT RULE OUT ENOUGH CONVERGENCE OCCURRING OVER THE DRY LINE FOR A STORM OR TWO TO INITIATION...SO HAVE PLACED SLIGHT CHANCES ALONG THE DRY LINE WITH FOCUS ON THE BETTER AREA OF 500MB LIFT DURING THE LATE AFTERNOON. WITH THE DEEP WELL MIXED ENVIRONMENT OVER THE AREA...STRONG DOWN BURST WINDS ARE POSSIBLE WITH ANY STORM THAT DEVELOPS DURING THE EARLY EVENING. THE SHORT WAVE TROUGH EXITS THE AREA AROUND MIDNIGHT...BRINGING PRECIPITATION CHANCES TO AN END. SOUTH WINDS WILL INCREASE DURING THE LATE MORNING AND AFTERNOON AS STRONGER WINDS ABOVE THE SURFACE MIX DOWN TO THE GROUND. THE SURFACE PRESSURE GRADIENT WILL ALSO TIGHTEN THROUGH THE AFTERNOON AHEAD OF THE COLD FRONT THAT WILL MOVE THROUGH DURING THE OVERNIGHT HOURS. WINDS WILL PEAK DURING THE LATE AFTERNOON...WITH GUSTS UP TO 40 MPH POSSIBLE. THE WINDS WILL EASE SOME DURING THEN EVENING AS MIXING CEASES...BUT WILL STILL BE GUSTY DUE TO THE TIGHT PRESSURE GRADIENT IN PLACE AHEAD OF THE COLD FRONT. DURING THE OVERNIGHT HOURS A COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST. LATEST CROSS SECTIONS SHOW THE LIFT TO BE SITUATED AHEAD OF THE FRONT IN THE DRIER AIR. WILL BE KEEPING THE FRONTAL PASSAGE FOR THE OVERNIGHT PERIOD DRY AS A RESULT. THE SATURDAY THROUGH FRIDAY PERIOD WILL START OFF WITH PRECIPITATION CHANCES ACROSS MOST OF THE AREA SATURDAY...FOLLOWING A SHORT WAVE TROUGH AND COLD FRONT THAT WILL MOVE THROUGH THE AREA DURING THE DAY. BULK OF THE MOISTURE WILL BE OVER THE NORTHERN HALF OF THE AREA...CAUSING PRECIPITATION CHANCES TO QUICKLY DECREASE OVER THE SOUTHERN PART OF THE AREA THAT WILL BE IN THE DRIER AIR. BEHIND THE FRONT WINDS WILL BE GUSTY...BUT SHOULD DECLINE THROUGH THE DAY AS THE FRONT MOVES FURTHER SOUTH. SATURDAY EVENING PRECIPITATION CHANCES CONTINUE AS THE SHORT WAVE TROUGH MOVES ACROSS THE EASTERN PART OF THE AREA. MODELS HAVE A SECOND SHORT WAVE TROUGH FOLLOWING THE FIRST ONE OVER THE WESTERN PART OF THE AREA. AM NOT TOO CONFIDENT THERE WILL BE MUCH MOISTURE FOR THE SECOND SHORT WAVE TO WORK WITH...BUT KEPT IN SLIGHT CHANCES FOR THE REST OF THE AREA TO STAY CONSIST ANT WITH NEIGHBORS. PRECIPITATION CHANCES RETURN WEDNESDAY TO THE EASTERN PART OF THE AREA AS ANOTHER SHORT WAVE TROUGH MOVES ACROSS THE AREA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1106 PM MDT WED MAY 16 2012 VFR EXPECTED THROUGH THE PERIOD AT KGLD AND KMCK. MID AND HIGH LEVEL CLOUDS WILL BE PREVALENT AHEAD OF AN UPPER LEVEL TROUGH THAT WILL MOVE ACROSS THE TERMINALS DURING AFTERNOON AND EARLY EVENING HOURS BEFORE EXITING THE AREA TOWARD THE END OF THE TAF PERIOD. A FEW THUNDERSTORMS ARE EXPECTED WITH THE TROUGH PASSAGE AND BEST GUESS IS AFTER 21Z. GIVEN THE ISOLATED NATURE WILL NOT INCLUDE A CB MENTION AT PRESENT TIME. SOUTH WINDS AROUND 20 KTS WITH HIGHER GUSTS EXPECTED AT KMCK AROUND 18Z-02Z. && .FIRE WEATHER... ISSUED AT 248 PM MDT WED MAY 16 2012 FRIDAY AFTERNOON SOUTH WINDS WILL STRENGTHEN...WITH GUSTS UP TO 40 MPH ACROSS THE AREA. RELATIVE HUMIDITIES WILL FALL INTO THE 10 TO 20 PERCENT RANGE DURING THE AFTERNOON FOR LOCATIONS WEST OF A MCCOOK TO GOVE LINE...LEADING TO HAZARDOUS FIRE WEATHER CONDITIONS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...007 SHORT TERM...DR LONG TERM...JTL AVIATION...DDT FIRE WEATHER...JTL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1244 PM EDT THU MAY 17 2012 .Forecast Update... Issued at 1135 AM EDT May 17 2012 The clouds that were moving in from the northeast earlier this morning dissipated right on schedule, leaving us with mostly sunny skies by 15Z. Surface dew points have been increasing and pooling over southern Kentucky this morning. HRRR has been trending much more bullish with convection in the south this afternoon. After coordination with neighboring offices, and considering the afternoon development we saw over the past two days, have decided to go ahead and throw in a SLGT CHC of showers/storms during peak heating this afternoon in the south. Will restrict PoPs to the south of where the 1000 foot overcast was earlier. Issued at 830 AM EDT May 17 2012 This update primarily dealt with a 1000 foot overcast that developed over the southern Blue Grass. It appears that the clouds should mix out by 15Z, but in the meantime we have significantly increased cloudcover in and near that patch of clouds. A shower managed to pop up over Hart County between 11Z and 12Z but it has since fallen apart. Munfordville web cam did show some elevated instability revealed in the cumuliform cloud structures overhead...as also seen on visible satellite channel. A rogue shower will still be possible in southeastern sections of the LMK CWA near a diffuse cold front, but coverage should remain minimal. Went ahead an increased PoPs to a silent 13% southeast of a BWG-LEX line. .Short Term (Today through Friday)... Issued at 308 AM EDT May 17 2012 The weak frontal boundary that brought scattered showers/storms to the region last evening has stalled across south-central KY early this morning. South of this boundary, winds are calm and dewpoints are still in the upper 50s. With this moist air in place, light ground fog will again be possible towards dawn, mainly over lakes or low-lying areas or river valleys. North of the boundary however, winds are out of the northeast with dewpoints dropping into the upper 40s. Even further north, a secondary dewpoint boundary across southern IN has upper 30 dewpoints behind it. Needless to say, high pressure over the Great Lakes is on the way. This surface high will push south and bring drier air into the region through the short-term period. Only hang up will be added cloud cover near the stalled boundary across the TN/KY border. Think this boundary will eventually push south into TN today, so precip should remain south of our CWA with dry weather forecast. With clear skies for the most part today, think we`ll be able to reach the upper 70s northeast into the lower 80s southwest. With high pressure continuing on Friday and even more dry air in place, good mixing and veering winds will allow for temps to climb even higher, with low to mid 80s being the rule under sunny skies again. Lows tonight will drop into the low to mid 50s with no fog expected. .Long Term (Friday Night through Wednesday)... Issued at 250 AM EDT May 17 2012 A mostly dry and quite warm weekend is setting up for the region as we remain under the influence of surface high pressure and an upper level ridge. Regarding precip chances Saturday and Sunday afternoon, there is still a lot of uncertainty as to whether any storms will be able to develop. The GFS continues to develop some precip, though it now paints the best chance on Sunday across the entire are, with less on Saturday. The ECMWF remains dry and we will continue to advertise a dry solution for now, though pops may be needed at some point in time. With southerly winds and mostly sunny skies under the high pressure, temperatures will be quite warm this weekend. Highs will top out in the mid to upper 80s with lows in the lower 60s. A front will begin to approach the region on Monday and move through Monday night into Tuesday. Isolated to scattered thunderstorms will develop ahead of this front on Monday. Storm coverage will increase Monday night and Tuesday as the front passes through the area. Beyond Tuesday the forecast is a bit less certain. The GFS is much faster than the ECMWF at clearing things out behind the front as the ECMWF is slower to move out an upper level low. There is quite a bit of spread in the ensembles on precip chances for Wednesday, so will carry a slight chance of shower/storms for now. With increased cloud/precip coverage Monday through Wednesday, high temperatures will be a bit cooler, in the upper 70s to lower 80s. Lows will continue to drop into the lower 60s. && .Aviation (18Z TAF Issuance)... Updated at 1244 PM EDT May 17 2012 High pressure moving by to the north will keep our skies mostly clear through the TAF period. A stray storm or two may pop up around BWG this afternoon but chances of the airport getting hit are very slim at this point. BWG avoided any sub-VFR fog this morning, and it appears that will be the case again Friday morning. Northeast breezes today will go calm tonight and veer slightly to the east and southeast tomorrow though they will remain light. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........13 Short Term.......AL Long Term........EER Aviation.........13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1135 AM EDT THU MAY 17 2012 .Forecast Update... Issued at 1135 AM EDT May 17 2012 The clouds that were moving in from the northeast earlier this morning dissipated right on schedule, leaving us with mostly sunny skies by 15Z. Surface dew points have been increasing and pooling over southern Kentucky this morning. HRRR has been trending much more bullish with convection in the south this afternoon. After coordination with neighboring offices, and considering the afternoon development we saw over the past two days, have decided to go ahead and throw in a SLGT CHC of showers/storms during peak heating this afternoon in the south. Will restrict PoPs to the south of where the 1000 foot overcast was earlier. Issued at 830 AM EDT May 17 2012 This update primarily dealt with a 1000 foot overcast that developed over the southern Blue Grass. It appears that the clouds should mix out by 15Z, but in the meantime we have significantly increased cloudcover in and near that patch of clouds. A shower managed to pop up over Hart County between 11Z and 12Z but it has since fallen apart. Munfordville web cam did show some elevated instability revealed in the cumuliform cloud structures overhead...as also seen on visible satellite channel. A rogue shower will still be possible in southeastern sections of the LMK CWA near a diffuse cold front, but coverage should remain minimal. Went ahead an increased PoPs to a silent 13% southeast of a BWG-LEX line. .Short Term (Today through Friday)... Issued at 308 AM EDT May 17 2012 The weak frontal boundary that brought scattered showers/storms to the region last evening has stalled across south-central KY early this morning. South of this boundary, winds are calm and dewpoints are still in the upper 50s. With this moist air in place, light ground fog will again be possible towards dawn, mainly over lakes or low-lying areas or river valleys. North of the boundary however, winds are out of the northeast with dewpoints dropping into the upper 40s. Even further north, a secondary dewpoint boundary across southern IN has upper 30 dewpoints behind it. Needless to say, high pressure over the Great Lakes is on the way. This surface high will push south and bring drier air into the region through the short-term period. Only hang up will be added cloud cover near the stalled boundary across the TN/KY border. Think this boundary will eventually push south into TN today, so precip should remain south of our CWA with dry weather forecast. With clear skies for the most part today, think we`ll be able to reach the upper 70s northeast into the lower 80s southwest. With high pressure continuing on Friday and even more dry air in place, good mixing and veering winds will allow for temps to climb even higher, with low to mid 80s being the rule under sunny skies again. Lows tonight will drop into the low to mid 50s with no fog expected. .Long Term (Friday Night through Wednesday)... Issued at 250 AM EDT May 17 2012 A mostly dry and quite warm weekend is setting up for the region as we remain under the influence of surface high pressure and an upper level ridge. Regarding precip chances Saturday and Sunday afternoon, there is still a lot of uncertainty as to whether any storms will be able to develop. The GFS continues to develop some precip, though it now paints the best chance on Sunday across the entire are, with less on Saturday. The ECMWF remains dry and we will continue to advertise a dry solution for now, though pops may be needed at some point in time. With southerly winds and mostly sunny skies under the high pressure, temperatures will be quite warm this weekend. Highs will top out in the mid to upper 80s with lows in the lower 60s. A front will begin to approach the region on Monday and move through Monday night into Tuesday. Isolated to scattered thunderstorms will develop ahead of this front on Monday. Storm coverage will increase Monday night and Tuesday as the front passes through the area. Beyond Tuesday the forecast is a bit less certain. The GFS is much faster than the ECMWF at clearing things out behind the front as the ECMWF is slower to move out an upper level low. There is quite a bit of spread in the ensembles on precip chances for Wednesday, so will carry a slight chance of shower/storms for now. With increased cloud/precip coverage Monday through Wednesday, high temperatures will be a bit cooler, in the upper 70s to lower 80s. Lows will continue to drop into the lower 60s. && .Aviation (06Z TAF Issuance)... Updated at 645 AM EDT May 17 2012 The weak cold front is still located across south-central KY. Based on BWG`s pressure, it may be just south of that location. Winds will remain light and variable at BWG for another 1-2 hours with a light haze, as well. Otherwise, this boundary will slowly sag southward, possibly leading to a stray shower near the BWG terminal through 18z. Will keep BWG dry though due to limited coverage. North of this boundary, LEX and SDF will continue to have decent northeasterly winds today (8-12 knots on average) with a few higher gusts. Expect FEW mid-level clouds at those terminals through midday with clear skies thereafter. With the front nearby, more SCT cloud coverage will affect BWG with cloud bases from 6-12kft. Tonight, skies will clear at all locations as winds veer a little to the east, not quite tapering off to calm overnight. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........13 Short Term.......AL Long Term........EER Aviation.........13
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1008 PM EDT FRI MAY 18 2012 .SYNOPSIS... HIGH PRESSURE WILL PROVIDE FOR DRY WEATHER WITH A WARMING TREND CONTINUING THROUGH THE WEEKEND. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL RETURN ON MONDAY AS A FRONTAL BOUNDARY APPROACHES FROM THE WEST. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... NO CHANGES TO PREVIOUS FORECAST, EVERYTHING IS ON TRACK. PREVIOUS DISCUSSION... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE AXIS EXTENDING FROM THE ARKLATEX REGION INTO THE LOWER GREAT LAKES. AT THE SURFACE, A 1025MB HIGH IS CENTERED ACROSS NEW ENGLAND AND EXTENDS SOUTHWESTWARD INTO THE UPPER OHIO VALLEY. MEANWHILE, A CLOSED LOW IS DEVELOPING OFF THE CAROLINA COAST. THE 500MB RIDGE WILL BUILD IN FURTHER INTO THE GREAT LAKES REGION TODAY AND TONIGHT WITH WEAK ANTI-CYCLONIC FLOW ALOFT CENTERED ACROSS NORTHERN OHIO BY 12Z SATURDAY. THIS WILL ALLOW ABUNDANT SUNSHINE TO CONTINUE INTO THE EVENING. WITH NEAR CALM WINDS AND CLEAR SKIES TONIGHT, RADIATIONAL COOLING WILL ALLOW FOR TEMPERATURES TO STEADILY DROP OFF. OVERNIGHT LOWS WILL RANGE FROM THE LOWER 40S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES TO THE LOWER 50S ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV. WITH SUPPORT FROM THE LAMP, PATCHY RADIATION FOG IS FORECAST TO DEVELOP OVERNIGHT ACROSS THE SOUTHEAST RIDGES. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... THERE IS ECMWF/GFS AGREEMENT THAT THE RIDGE WILL CONTINUE TO BUILD NORTHEASTWARD WITH ITS AXIS CENTERED ACROSS THE AREA ON SUNDAY. THIS WILL ALLOW FOR DRY WEATHER TO CONTINUE SATURDAY THROUGH MOST OF SUNDAY. SOME UNCERTAINTY ENTERS THE FORECAST LATE SUNDAY, AS THE UPPER LOW BEGINS TO RETROGRADE. THIS HAS BEEN ACCOUNTED FOR WITH SCHC POPS ACROSS THE SOUTHEAST RIDGES. WITH GFS 850MB TEMPS WARMING TO 14-16C, HIGHS ON SATURDAY AND SUNDAY ARE 10 TO 15 DEGREES ABOVE NORMAL WITH MANY LOWLAND LOCATIONS WARMING INTO THE MID 80S. AROUND 30 DEGREE DIURNAL RANGES ARE ANTICIPATED AS A WEAK FLOW WITH DRY AIR ALLOWS FOR STRONG RADIATIONAL COOLING EACH NIGHT. RIDGING WILL BECOME PINCHED OFF AS THE CLOSED LOW ACROSS THE CAROLINAS CONTINUES TO RETROGRADE AND A TROUGH MOVES INTO THE GREAT LAKES ON MONDAY. THIS WILL ALLOW FOR ATLANTIC-STREAM MOISTURE TO FILTER INTO THE AREA WITH MORE HUMID CONDITIONS ANTICIPATED. IN ADDITION, A FRONTAL BOUNDARY WILL APPROACH FROM THE WEST LATE ON MONDAY. MOISTURE WILL CONTRIBUTE TO INCREASING INSTABILITY AND THUS THE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA MONDAY AFTERNOON. INCREASING CLOUDINESS WILL LIMIT TEMPS SLIGHTLY ON MONDAY, WITH HIGHS STILL AROUND 10 DEGREES ABOVE NORMAL. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MODELS CONTINUE TO DISAGREE SOMEWHAT WITH REGARD TO TIMING OF THE FRONT APPROACHING FROM THE WEST AND ON THE EXTENT OF RETROGRESSION OF EAST COAST LOW EARLY NEXT WEEK. STAYED CLOSE TO HPC GUIDANCE WHICH STILL LEANS TOWARD FASTER GFS TIMING WITH THE FRONT AND PUSHES THE MAIN AREA OF PRECIPITATION EAST OF THE REGION BY WEDNESDAY NIGHT. A WEAK SURFACE RIDGE SHOULD PROVIDE GENERALLY DRY WEATHER FOR THURSDAY INTO FRIDAY FOR MUCH OF THE FORECAST AREA. MOIST SOUTHEAST FLOW FROM THE ATLANTIC DEPICTED BY THE ECMWF COULD MAINTAIN SCATTERED PRECIPITATION OVER THE RIDGES ON THURSDAY NIGHT AND FRIDAY. TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS AND LIGHT EAST WINDS WILL PREVAIL THROUGH THE TAF PERIOD AS A SURFACE RIDGE HOLDS ALONG THE APPALACHIANS. .OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY... THE SURFACE RIDGE WILL MAINTAIN VFR WEATHER THROUGH SUNDAY NIGHT. A FRONT WILL APPROACH FROM THE WEST LATE MONDAY WHILE A LOW PRESSURE SYSTEM MOVES INLAND FROM THE CAROLINA COAST. MOISTURE WILL INCREASE ACROSS THE REGION BY LATE MONDAY ALONG WITH THE POTENTIAL FOR RESTRICTIONS IN SHOWERS AND THUNDERSTORMS. SCATTERED PRECIPITATION SHOULD PERSIST THROUGH WEDNESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
358 PM EDT THU MAY 17 2012 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE NORTHEASTERN STATES WHILE LOW PRESSURE MOVES SLOWLY NORTH OFF THE CAROLINA COAST THROUGH THE WEEKEND. && .NEAR TERM /THROUGH FRIDAY/... THE COLD FRONT HAS PUSHED TO SOUTH INTO THE CAROLINAS AS SURFACE HIGH PRESSURE OVER THE EASTERN GREAT LAKES BEGINS TO INFLUENCE THE REGION. UPPER LEVEL LOW PRESSURE WAS SPINNING OVER EASTERN GEORGIA. NORTHEAST WINDS HAVE KEPT CLOUDS (BASES 1 TO 3K FT) OVER PORTIONS OF SE VIRGINIA AND NE NORTH CAROLINA. SHOWERS APPEAR TO HAVE ENDED OVER OUR AREA AS DRIER AIR MOVES IN ALOFT. WILL KEEP CONSIDERABLE CLOUDINESS OVER FAR SOUTHEAST PORTIONS AND THE REST OF THE AREA WILL GRADUALLY CLEAR. LOW TEMPERATURES WILL RANGE FROM AROUND 50 OVER THE MD LOWER EASTERN SHORE AND THE NORTHERN PIEDMONT TO NEAR 60 ON THE SRN VA/NC COAST. HIGH PRESSURE REMAINS ANCHORED ACROSS THE NORTHEAST U.S. ON FRIDAY. MEANWHILE...THE AFOREMENTIONED COLD FRONT STALLS OFF THE SOUTHEAST COAST. LOW PRESSURE FORMS ALONG THIS FRONTAL BOUNDARY OVER THE WESTERN ATLANTIC. THE COMBINATION OF HIGH PRESSURE TO THE NORTH AND LOW PRESSURE OFF THE COAST WILL RESULT IN PERSISTENT ONSHORE FLOW. THIS WILL MAINTAIN PLEASANT HIGH TEMPERATURES WITH READINGS RANGING FROM THE LOW 70S ALONG THE COAST TO THE UPPER 70S OVER THE PIEDMONT. ON FRIDAY...SKIES WILL BE MOSTLY CLEAR WELL INLAND BUT MOSTLY CLOUDY ACROSS SOUTHEAST VA AND NORTHEAST NORTH CAROLINA. THERE WILL BE A SLIGHT CHANCE FOR RAIN OVER A SMALL PORTION OF OUR NORTH CAROLINA COUNTIES NEAR THE COAST.. HIGH TEMPERATURES WILL RANGE FROM THE MID TO UPPER 60S NEAR THE COAST TO THE MID TO UPPER 70S WELL INLAND. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... UNCERTAINTY CONTINUES FOR THE UPCOMING WEEKEND DUE TO QUESTIONS SURROUNDING THE PROGRESS OF THE SYSTEM IN THE SOUTHEAST. SOME GUIDANCE RETROGRADES THE LOW TO THE WEST OVER THE CAROLINAS AND THEN DISSIPATES. THIS SOLUTION WOULD BRING WET WEATHER TO THE AREA THIS WEEKEND. IT DOESN`T APPEAR THAT BLOCKING TO THE NORTH WOULD BE STRONG ENOUGH FOR THIS TO OCCUR. HPC PREFERS THE TREND OF THE EURO AND GFS WITH KEEPING THE LOW OFFSHORE AND THUS A RELATIVELY DRY SOLUTION FOR THE MID ATLANTIC STATES. THE EURO SEEMS TO BE FAIRLY CONSISTENT AND APPEARS RIGHT NOW TO HAVE THE BEST HANDLE ON IT. THE RESULT IS SLIGHT CHANCE OF RAIN NEAR THE NORTH CAROLINA COAST FRIDAY NIGHT INCREASING TO A 30 PERCENT CHANCE OF RAIN BY SATURDAY NIGHT. SLIGHT CHANCE POPS SPREADS INTO SOUTHEAST VIRGINIA BY SATURDAY NIGHT AND TO OUR ENTIRE AREA ON SUNDAY. IN SUMMARY...MOST OF THE AREA IS FORECAST TO BE DRY THIS WEEKEND. RESIDENTS ESPECIALLY NEAR THE COAST SHOULD CONTINUE TO MONITOR THE LATEST FORECAST FOR UPDATES. GENERALLY DID A BLEND OF NAM AND MAV GUIDANCE AND BLENDED IT WITH MOS GUIDE FOR TEMPERATURES. THERE IS A SIGNIFICANT DIFFERENCE WITH HIGH TEMPERATURES SATURDAY BETWEEN THE MET AND MAV DUE TO A VARIATION IN FORECAST CLOUD COVER (THE MAV BEING 10 OR MORE DEGREES WARMER THAN THE MET ACROSS INLAND AREAS. HIGH TEMPERATURES SATURDAY AND SUNDAY ARE FORECAST TO BE IN THE 70S EXCEPT UPPER 60S NEAR THE COAST (POSSIBLY COOLER IF RAIN DEVELOPS). LOWS IN THE MID TO UPPER 40S WEST OF INTERSTATE 95 SATURDAY MORNING (DUE TO MOSTLY CLEAR SKIES) WILL RANGE TO THE MID 50S TOWARD THE COAST. LOWS SUNDAY MORNING ARE FORECAST TO BE IN THE 50S ACROSS THE AREA. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... BROAD UPR-LVL TROF REMAINS IN PLACE OVR THE EASTERN SEABOARD INTO ERLY NEXT WEEK LEADING TO A TRICKY FORECAST SCENARIO. VARIOUS SHORTWAVES PIVOTING AROUND THE TROF WILL LEAD TO SFC LOW DEVELOPMENT OFFSHORE...WITH MODELS CONTINUING TO DIFFER ON THE TIMING AND STRENGTH OF THESE SFC LOWS. 12Z ECMWF BRINGS A LOW UP THE EASTERN SEABOARD MON INTO TUE LEADING TO A BETTER CHC FOR RAIN (ESPECIALLY OVR EASTERN AREAS) THAN THE 12Z GFS WHICH STALLS THE SFC LOW NEAR THE SOUTH CAROLINA COAST MON AND TUE. WILL CAP POPS AT 30% FOR NOW. THE BROAD UPR-LVL TROF WILL BE REINFORCED INTO THE MIDDLE OF NEXT WEEK AS PLENTY OF ENERGY SLIDES DOWN THE WESTERN HALF OF THE TROF FROM THE RIDGE OVR THE HIGH PLAINS. SO WILL MAINTAIN SLGT CHC TO CHC POPS FOR THE REMAINDER OF THE LONG TERM PERIOD. TEMPS WILL BE SEASONABLE...HIGHS GENERALLY IN THE UPR 70S TO LWR 80S. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... COLD FRONT HAS MOVED SOUTH OF THE AREA EARLY THIS AFTERNOON. CAN SEE ON VWP THAT WINDS HAVE SHIFTED TO NE THRU AT LEAST 7 THOUSAND FEET. THIS IS BRINGING SOME MOISTURE FROM OFF THE ATLANTIC AND WITH COOLING TEMPERATURES GETTING SOME CLOUD FORMATION GENERALLY AROUND 2 THOUSAND FEET. THIS IS WELL DEPICTED BY RH AT 925 MB ON THE RAP MODEL. WILL USE THE TIMING FROM THE RAP TO SCATTERED THE CLOUDS FROM NORTH TO SOUTH AROUND SUNRISE. SBY ALREADY HAS DRY AIR COMING IN AND THIS IS KEEPING CLOUDS SCATTERED THERE. MODELS ALL HAVE DIFFERING SOLUTIONS WITH CUTOFF LOW TO THE SOUTH OF THE AREA AND THIS IMPACTS MOISTURE FEED OFF THE ATLANTIC. THE NAM BRINGS LOW CLOUDS BACK AS EARLY AS FRIDAY MORNING BUT NONE OF THE OTHER MODELS DO. WHILE FEEL WITH FLOW OFF THE WATER COULD HAVE AT LEAST SOME SCATTERED CLOUDS SO WENT AROUND 3 THOUSAND SCATTERED. AS THE WEEKEND PROGRESSES MORE MOISTURE WILL COME IN FROM THE ATLANTIC AND CEILINGS WILL BECOME MVFR AND POTENTIALLY DOWN TO IFR BY LATE IN THE WEEKEND. WITH DIFFERENT TIMINGS FROM THE MODELS THERE IS STILL A LOT OF UNCERTAINTY ON THE TIMING OF THESE CONDITIONS. && .MARINE... HI PRES WILL CONTINUE TO BLD OVR THE MID ATLANTIC THIS EVNG FOLLOWING THE COLD FROPA EARLIER TDY. THIS WILL LEAD TO PERSISTENT ONSHORE FLOW AND INCREASING EASTERLY SWELL CAUSING 5 FT SEAS OVR COASTAL WATERS OVRNGT. SCA HEADLINES ALSO IN EFFECT OVR THE BAY/SOUND/LWR JAMES RIVER WHERE NE WNDS WILL INCREASE OVRNGT. DUE TO UNCERTAINTY REGARDING START TIME OF REACHING SCA WNDS...THESE WNDS EXPECTED WITHIN 12 HR...AND HEADLINES ALREADY IN PLACE...DECIDED TO PUT THE SCA INTO EFFECT WITH THIS FORECAST PACKAGE. OTHER THREE MARINE ZONES (OVR THE RIVERS) MAY NEED TO BE INCLUDED AS WELL AT SOME POINT. NE WNDS INCREASE FRI AND FRI NGT AS LO PRES MOVES UP THE SE COAST WHILE HI PRES HOLDS STEADY OVR THE NE...LEADING TO A TIGHTENING PRES GRADIENT. FAVORED SREF/ECMWF REGARDING WND DIRECTION WITH THIS SYSTM. WILL END THE HEADLINES UP FOR WNDS SAT MRNG DUE TO UNCERTAINTY REGARDING THE TRACK OF THE LOW PRES SYSTM. SEAS EXPECTED TO STAY AOA 5 FT THRU THE DAY SAT. && .EQUIPMENT... ASOS OBSERVATION FOR PHF IS NOT AVAILABLE ONLINE DUE TO COMMS ISSUE. THE PROBLEM IS BEING WORKED ON AND RTS IS NOT KNOWN AT THIS TIME. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT SATURDAY FOR ANZ630>634- 638. SMALL CRAFT ADVISORY UNTIL 7 PM EDT SATURDAY FOR ANZ650-652- 654-656-658. && $$ SYNOPSIS...LSA NEAR TERM...LSA SHORT TERM...LSA LONG TERM...MAS AVIATION...JAB MARINE...MAS EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
145 PM EDT THU MAY 17 2012 .SYNOPSIS... HIGH PRESSURE OVER THE GREAT LAKES BUILDS IN FROM THE NORTHWEST TODAY BEHIND A COLD FRONT AND BECOMES ANCHORED OVER THE NORTHEAST FROM FRIDAY THROUGH THE WEEKEND. MEANWHILE...THE COLD FRONT STALLS OFF THE SOUTHEAST COAST. LOW PRESSURE DEVELOPS ALONG THIS FRONT AND MEANDERS OVER THE WESTERN ATLANTIC THROUGH THE WEEKEND WITH MUCH UNCERTAINTY WITH RESPECT TO THE EVENTUAL TRACK OF THE SYSTEM. && .NEAR TERM /THROUGH FRIDAY/... EARLY AFTN UPDATE INCREASED CLOUD COVER FOR TODAY AS WIDESPREAD CUMULUS HAS FORMED. HIGH CLOUDS ARE ALSO CONTRIBUTING TO THE CLOUD COVER. ALSO INCLUDED SLGT CHC THUNDER IN PORTIONS OF THE NORTH CAROLINA COUNTIES. ONSHORE WINDS ARE KEEPING SURFACE DEW POINTS RATHER HIGH IN THE SOUTHEAST AND MOST INLAND AREAS HAVE READINGS IN THE UPPER 50S TO LOWER 60S. THIS IS RESULTING IN A LOW LCL OF 15 TO 25 HUNDRED FEET (THUS THE CUMULUS) ACRS SRN AND EASTERN SECTIONS OF THE CWA. THE HIGHER DEW POINTS ARE HELPING TO PRODUCE WIDELY SCATTERED CONVECTIVE SHOWERS AND ISOLATED TSTMS OVER PORTIONS OF THE NORTH CAROLINA COUNTIES. DRYING ALOFT SHOULD KEEP ANY TSTMS TO A MINIMUM AND ARE EXPECTED TO END BY 20Z. THE COLD FRONT HAS PUSHED SOUTH OF THE AREA AS OF 14Z. DEW POINTS ARE STILL IN THE 60S TO AROUND 70 OVER MOST OF THE AREA BUT SHOULD FALL INTO THE UPR 40S TO LWR 50S OVER NORTHERN SECTIONS BY THIS AFTN. CLOUDS WILL KEEP HIGH TEMPERATURES GENERALLY IN THE 70S WITH ONSHORE FLOW HOLDING AFTERNOON TEMPERATURES NEAR THE COAST IN THE UPPER 60S. WARMEST READINGS WILL BE IN THE MID TO UPR 70S. FROM PREVIOUS DISCUSSION... HIGH PRESSURE SHOULD CONTINUE TO PREVAIL TONIGHT. THE SKY SHOULD RANGE FROM MOSTLY CLEAR OVER MOST OF THE AREA TO PARTLY CLOUDY OVER COASTAL NE NC. LOW TEMPERATURES ARE EXPECTED TO RANGE FROM THE UPPER 40S N...TO THE MID TO UPPER 50S OVER EXTREME SE VA AND COASTAL NE NC. HIGH PRESSURE REMAINS ANCHORED ACROSS THE NORTHEAST US ON FRIDAY. MEANWHILE...THE AFOREMENTIONED COLD FRONT STALLS OFF THE SOUTHEAST COAST. LOW PRESSURE FORMS ALONG THIS FRONTAL BOUNDARY OVER THE WESTERN ATLANTIC. THE COMBINATION OF HIGH PRESSURE TO THE NORTH AND LOW PRESSURE OFF THE COAST WILL RESULT IN PERSISTENT ONSHORE FLOW. THIS WILL MAINTAIN PLEASANT HIGH TEMPERATURES WITH READINGS RANGING FROM THE LOW 70S ALONG THE COAST TO THE UPPER 70S OVER THE PIEDMONT. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... THERE IS MUCH UNCERTAINTY FOR THE UPCOMING WEEKEND. INDIVIDUAL MODEL SOLUTIONS HAVE LARGELY BEEN CONSISTENT FROM RUN-TO-RUN...BUT INCONSISTENT AMONGST EACH OTHER WITH RESPECT TO THE EVENTUAL TRACK OF THE AFOREMENTIONED AREA OF LOW PRESSURE OFF THE WESTERN ATLANTIC. THE NAM AND GEM GLOBAL MOVE THE LOW PRESSURE SYSTEM NORTHWARD OFF THE OUTER BANKS BEFORE RETROGRADING IT WESTWARD INTO THE MID ATLANTIC OVER THE WEEKEND. THIS WOULD LEAD TO WET CONDITIONS ESPECIALLY ALONG THE COAST. THE ECMWF IS SLOWER WITH WITH ANY MOISTURE NOT ARRIVING UNTIL LATER IN THE WEEKEND AND EARLY NEXT WEEK. MEANWHILE...THE GFS IS MOST OPTIMISTIC WITH HIGH PRESSURE PREVAILING THROUGH THE WEEKEND. ADDITIONALLY THE SREF MEAN IS MORE IN LINE WITH THE NAM/GEM. CHANCE POPS WILL BE FORECAST FOR SE COASTAL LOCATIONS THROUGH THE WEEKEND ALONG WITH INCREASED SKY COVER MAINLY ALONG THE COAST. ONSHORE FLOW WILL KEEP HIGHS IN THE 70S...BUT IF RAIN DOES MOVE OVER THE COAST HIGHS WILL BE COOLER. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... BROAD UPR-LVL TROF REMAINS IN PLACE OVR THE EASTERN SEABOARD INTO ERLY NEXT WEEK SO WILL KEEP SLGT CHC/LOW CHC POPS IN THE FORECAST. HIGH TEMPERATURES APPEAR TO WARM INTO THE LOW 80S BY THE MIDDLE OF NEXT WEEK. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... COLD FRONT HAS MOVED SOUTH OF THE AREA EARLY THIS AFTERNOON. CAN SEE ON VWP THAT WINDS HAVE SHIFTED TO NE THRU AT LEAST 7 THOUSAND FEET. THIS IS BRINGING SOME MOISTURE FROM OFF THE ATLANTIC AND WITH COOLING TEMPERATURES GETTING SOME CLOUD FORMATION GENERALLY AROUND 2 THOUSAND FEET. THIS IS WELL DEPICTED BY RH AT 925 MB ON THE RAP MODEL. WILL USE THE TIMING FROM THE RAP TO SCATTERED THE CLOUDS FROM NORTH TO SOUTH AROUND SUNRISE. SBY ALREADY HAS DRY AIR COMING IN AND THIS IS KEEPING CLOUDS SCATTERED THERE. MODELS ALL HAVE DIFFERING SOLUTIONS WITH CUTOFF LOW TO THE SOUTH OF THE AREA AND THIS IMPACTS MOISTURE FEED OFF THE ATLANTIC. THE NAM BRINGS LOW CLOUDS BACK AS EARLY AS FRIDAY MORNING BUT NONE OF THE OTHER MODELS DO. WHILE FEEL WITH FLOW OFF THE WATER COULD HAVE AT LEAST SOME SCATTERED CLOUDS SO WENT AROUND 3 THOUSAND SCATTERED. AS THE WEEKEND PROGRESSES MORE MOISTURE WILL COME IN FROM THE ATLANTIC AND CEILINGS WILL BECOME MVFR AND POTENTIALLY DOWN TO IFR BY LATE IN THE WEEKEND. WITH DIFFERENT TIMINGS FROM THE MODELS THERE IS STILL A LOT OF UNCERTAINTY ON THE TIMING OF THESE CONDITIONS. && .MARINE... COLD FRONT HAS NOW PUSHED SOUTH OF THE AREA. WITH THE LOW LEVEL FLOW COMING OUT OF THE NE AND TEMPERATURES COOLING GETTING A DECK OF CLOUDS BETWEEN 2 AND 3 THOUSAND FEET OVER MUCH OF THE AREA. THIS IS COLD FRNT WILL PUSH THRU THE MARINE AREA FM N TO S THRU THIS MORNG...WITH LGT SSW WNDS SHIFTING TO THE NNE AND INCREASING TO 15 TO 20 KT. WILL HAVE SCA FOR THE CHES BAY DURING TDY...THEN HAVE SCA FOR THE SRN TWO CHES BAY ZNS...CURRITUCK SND...AND ALL THE CSTL ZNS FM LATE THIS AFTN THRU LATE FRI NGT...AS NE WNDS 15 TO ARND 20 KT PRODUCES WAVES 3 TO 4 FT IN THE SRN CHES BAY...AND SEAS 5 TO 6 FT OVR THE CSTL ZNS. THIS NE FLO WILL RESULT FM HI PRES BLDNG BY TO THE N AND LO PRES LINGERING OFF THE MID ATLC CST. && .EQUIPMENT... ASOS OBSERVATION FOR PHF IS NOT AVAILABLE ONLINE DUE TO COMMS ISSUE. THE PROBLEM IS BEING WORKED ON AND RTS IS NOT KNOWN AT THIS TIME. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT SATURDAY FOR ANZ632-634. SMALL CRAFT ADVISORY UNTIL 7 AM EDT SATURDAY FOR ANZ633-650- 652-654-656-658. SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ630- 631. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ/LSA SHORT TERM...AJZ LONG TERM...MAS AVIATION...JAB MARINE...TMG EQUIPMENT...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
149 PM EDT THU MAY 17 2012 .SYNOPSIS... ISSUED AT 512 AM EDT THU MAY 17 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM THE PLAINS INTO CNTRL CANADA AND A DOWNSTREAM TROUGH FROM QUEBEC INTO THE NE CONUS RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...HIGH PRES WAS CENTERED OVER LOWER MI WHILE LOW PRES WAS DEVELOPING OVER THE PLAINS FROM SRN SASK INTO WRN SOUTH DAKOTA. MID LEVEL WARM ADVECTION AHEAD OF A WARM FRONT OVER THE CNTRL PLAINS SUPPORTED DEVELOPING SHRA AND A FEW TSRA OVER SW MN. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 512 AM EDT THU MAY 17 2012 TODAY...EXPECT THE BAND OF STRONGER 310K ISENTROPIC LIFT AND POSITION OF THE 750-650 MB WARM FRONT TO EXPAND TO THE ENE TODAY...PER NAM/GFS. HOWEVER...SINCE THE PCPN IS MOVING AWAY FROM THE GREATER LOW LEVEL MOISTURE INTO THE DRY LOW LEVEL AIRMASS TO THE EAST...PER 00Z MPX/INL/GRB SOUNDINGS...THE PCPN SHOULD REMAIN LIGHT AND MAINLY TO THE WEST AND SOUTH OF THE CWA. LOCATIONS FROM IWD-IMT WILL SEE THE BEST CHANCE OF ANY PCPN BUT ONLY SLIGHT CHANCE POPS WERE INCLUDED WITH ANY PCPN AMOUNTS LESS THAN A TENTH OF AN INCH. OTHERWISE...WAA WILL HELP PUSH TEMPS INTO THE MID 50S TO LOWER 70S DESPITE AN INCREASE IN MID HIGH CLOUDS. TONIGHT...THE FOCUS OF THE LLJ AND STRONGEST MOISTURE TRANSPORT IS EXPECTED OVER NE MN AND NW WI INTO WRN LAKE SUPERIOR. AREAS OF SHRA/TSRA SHOULD DEVELOP AND EVENTUALLY SPREAD TO THE EAST AFFECTING MAINLY THE NW HALF OF THE CWA AS THE LLJ VEERS OVERNIGHT. HOWEVER...THERE IS STILL SIGNIFICANT UNCERTAINTY WITH THE TIMING/POSITION OF THE CONVECTION. FRIDAY...ANY LEFTOVER SHRA/TSRA OVER MAINLY NORTH UPPER MI INTO LAKE SUPERIOR SHOULD SLIDE TO THE ENE AND DIMINISH DURING THE MORNING AS THE LLJ WEAKENS. THE COMBINATION OF BUILDING MID-LVL RDG HEIGHTS AND 850 MB WARM FRONT LIFTING WELL NORTH OF THE AREA SHOULD KEEP THE CWA DRY FRI AFTERNOON. RESIDUAL CLOUDS FROM CONVECTION SHOULD DISSIPATE FRI AFTERNOON ALLOWING FOR INCREASED SUNSHINE. MIXING OF 850 MB TEMPS OF AROUND 16C TO THE SFC SHOULD ALLOW FOR HIGH TEMPS FRIDAY TO REACH INTO THE LOWER 80S OVER WRN INTERIOR LOCATION. COOLER SRLY FLOW OFF LAKE MI WILL KEEP INLAND HIGHS OVER ERN COUNTIES IN THE LOW TO MID 70S. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 512 AM EDT THU MAY 17 2012 PERIOD STARTS 00Z SAT WITH A 500MB RIDGE OVER THE CWA...AND A 500MB TROUGH OVER THE INTERMOUNTAIN WEST. AT THE SFC...994MB LOW PRESSURE WILL BE STRETCHED E FROM ERN CO TO SRN ND...AND WITH HIGH PRESSURE SITTING OVER THE ERN SEABOARD...THAT PUTS US UNDER S/SSW FLOW. THAT/S RIGHT...WE WILL BE IN THE WARM SECTOR AS THE WARM FRONT ASSOCIATED WITH THE SYSTEM TO OUR W WILL BE N OF LAKE SUPERIOR BY 00Z SAT. AND WARM IT WILL BE WITH 850MB TEMPS AROUND 17C. FRI NIGHT AND SAT...SOLID S/SW FLOW IN THE WARM LOW LEVELS WILL KEEP TEMPS FROM FALLING TOO FAR FRI NIGHT...ESPECIALLY IN DOWNSLOPING AREAS. HAVE LOW TEMPS AROUND 60 IN THE DOWNSLOPE AREAS...AND IN THE UPPER 40S TO 50S ELSEWHERE. WITH HIGHER DEW PTS AND WAA...COULD SEE FOG OVER MAINLY NRN LAKE SUPERIOR AND EVENTUALLY NRN LAKE MI /WHICH WOULD LAST UNTIL FROPA SUNDAY/...WHICH I ADDED TO THE FORECAST FOR FRI NIGHT THROUGH SUN. 850MB TEMPS STAY AROUND 17C THROUGH SAT...WITH GOOD S/SW FLOW CONTINUING...ALLOWING MIXING TO AROUND 800MB. THIS YIELDS HIGH TEMPS IN THE 80S OVER THE W HALF AND NEAR LAKE SUPERIOR OVER THE E HALF...WITH HIGHS IN THE 60S CLOSE TO NRN LAKE MI DUE TO S/SSW FLOW OF THE RELATIVELY COLD LAKE. ATMOSPHERE LOOKS TOO DRY AND TOO CAPPED FOR CONVECTION TO FORM ON SAT...WHICH IS GOOD SINCE WE SHOULD HAVE 1500-2000J/KG OF CAPE SAT AFTERNOON. LOWERED DEW PTS A FEW DEGREES AS MIXING WILL ALLOW DRY AIR TO GET TO THE SFC. THIS LEADS TO MIN RH VALUES DOWN OF 25 TO 35 PERCENT OVER THE W HALF OF UPPER MI...AND GREATER THAN 35 PERCENT RH OVER THE E HALF. THIS BECOMES MORE PROBLEMATIC WHEN CONSIDERING WINDS WILL BE SLY AT 15-20MPH WITH GUSTS OF 25-35MPH. LOOKS LIKE IT MAY BE A CRITICAL FIRE WEATHER DAY...BUT THAT WILL NEED TO BE LOOKED AT MORE CLOSELY BY LATER SHIFTS FOR POSSIBLE FIRE WEATHER HEADLINES. SAT NIGHT THROUGH MON...BY 00Z SUN...THE UPPER TROUGH WILL HAVE MOVED FARTHER E...WITH A SHORTWAVE TROUGH OVER MANITOBA...AND POSSIBLY ANOTHER OVER KS/NE. THE SFC LOW WILL HAVE WEAKENED TO 1002MB AS IT MOVED TO N OF THE MN ARROWHEAD. THIS PUTS THE COLD JUST W OF LAKE SUPERIOR AT 00Z SUN. SAT NIGHT WILL BE ANOTHER WARM ONE WITH CONTINUED STRONG LOW LEVEL FLOW AND WARM LOW LEVEL TEMPS. OVERNIGHT LOWS LOOK TO BE IN THE 50S AND LOW 60S. DIFFERING MODEL SOLUTIONS BEGIN TO LOWER CONFIDENCE ON EXACT TIMING OF THE COLD FRONT/PRECIP DUE MAINLY WITH HOW TO HANDLE A SHORTWAVE MOVING AROUND THE MAIN UPPER TROUGH SAT NIGHT INTO SUN. THE GFS CONTINUES TO BE THE MOST AGGRESSIVE WITH THE SHORTWAVE...SHOWING IT STRONGER THAN PRETTY MUCH ANY OTHER MODEL. THIS MEANS THE GFS ALSO BRINGS THE COLD FRONT THROUGH FASTER THAN OTHER MODELS. FOR THIS REASON...WILL NOT PUT AS MUCH OF THE GFS INTO THIS FORECAST. WITH THE IDEA THAT THE GFS IS ABOUT 6 HOURS TOO FAST WITH FROPA...THE FRONT SHOULD MOVE OVER WRN UPPER MI SUN AFTERNOON...AND MOVE TO ERN UPPER MI BY 12Z MON...NOTE THE SLOW EASTWARD PROGRESSION OF THE FRONT. SBCAPES OF AROUND 1000-1500J/KG WILL BE POSSIBLE SUN AFTERNOON AHEAD OF THE FRONT...BUT CONFIDENCE IN THIS IS A BIT LOW RIGHT NOW DUE TO MODEL TIMING DIFFERENCES AND UNCERTAINTY IN HOW MUCH CLEARING WILL OCCUR AHEAD OF THE FRONT. 0-6KM BULK SHEAR LOOKS TO BE AROUND 30KTS...SUFFICIENT FOR ORGANIZED CONVECTION. SO...IT LOOKS LIKE SOME STRONG TO SEVERE STORMS WILL BE A POSSIBILITY SUN AFTERNOON/EVENING...BUT CONFIDENCE IS STILL LIMITED. THE COLD FRONT LOOKS TO COMPLETELY CLEAR THE CWA AROUND 18Z MON...AS THE UPPER TROUGH AND A SFC RIDGE MOVE INTO THE WRN CWA. 850MB TEMPS OF AROUND 7C MON AFTERNOON WILL MAKE FOR COOLER TEMPS IN THE 60S...EXCEPT IN THE 50S NEAR LAKE SUPERIOR IN THE NLY WINDS. MON NIGHT THROUGH WED...EXPECT A GRADUAL WARMING TREND AS AN UPPER RIDGE MOVES OVERHEAD AND SFC RIDGING SLOWLY MOVES TO E OF THE CWA BY WED AFTERNOON. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 148 PM EDT THU MAY 17 2012 WARM FRONT OVER SOUTHERN MINNESOTA WILL LIFT THROUGH UPPER MICHIGAN LATE TONIGHT AND INTO LK SUPERIOR AND ONTARIO BY LATE DAY FRIDAY. MAY SEE SHOWERS AS THE FRONT MOVES THROUGH...BUT AIR MASS OVER UPR MICHIGAN IS QUITE DRY SO THINK COVERAGE WILL REMAIN SCATTERED. BEST CHANCE FOR RAIN IS EARLY THIS AFTN AT IWD AND OVERNIGHT TONIGHT AT CMX. ISOLD TSRA MAY OCCUR TONIGHT AT IWD AND CMX...BUT CONFIDENCE IS TOO LOW TO PUT INTO FCST. MAIN HAZARD AT ALL TAF SITES TONIGHT IS LOW LEVEL WIND SHEAR AS SOUTHWEST LOW-LEVEL JET UP TO 45 KTS MOVES OVER THE AREA. SFC WINDS WILL BE GENERALLY LIGHT AND MAINLY SOUTH OR SOUTH-SOUTHEAST DIRECTION SO THERE WILL BE SOME DIRECTIONAL SHEAR AS WELL. ANY LLWS WILL END AROUND SUNRISE FRIDAY. GUSTY SW WINDS WILL DEVELOP FRIDAY AS MID CLOUDS SCATTER OUT. GIVEN THE DRY AIR OVR THE REGION...EVEN IF SHRA/TSRA OCCUR...EXPECT VFR CONDITIONS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 512 AM EDT THU MAY 17 2012 WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SHIFT TO THE LOWER GREAT LAKES THIS AFTERNOON...BEFORE PUSHING OFF THE MID ATLANTIC SHORELINE ON FRIDAY INTO SATURDAY. LOW PRESSURE OVER SOUTHERN SASKATCHEWAN AND THE WESTERN DAKOTAS WILL PUSH ACROSS THE NORTHERN AND CENTRAL PLAINS TONIGHT THROUGH SATURDAY...BEFORE SLIDING NORTH INTO ONTARIO SATURDAY. THIS WILL ALLOW A COLD FRONT TO PUSH ACROSS THE UPPER GREAT LAKES SUNDAY INTO EARLY MONDAY. BEHIND THE FRONT...HIGH PRESSURE WILL BUILD IN FROM THE CENTRAL AND NORTHERN PLAINS THROUGH TUESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...TITUS AVIATION...JLA MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 AM EDT THU MAY 17 2012 .SYNOPSIS... ISSUED AT 512 AM EDT THU MAY 17 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM THE PLAINS INTO CNTRL CANADA AND A DOWNSTREAM TROUGH FROM QUEBEC INTO THE NE CONUS RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...HIGH PRES WAS CENTERED OVER LOWER MI WHILE LOW PRES WAS DEVELOPING OVER THE PLAINS FROM SRN SASK INTO WRN SOUTH DAKOTA. MID LEVEL WARM ADVECTION AHEAD OF A WARM FRONT OVER THE CNTRL PLAINS SUPPORTED DEVELOPING SHRA AND A FEW TSRA OVER SW MN. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 512 AM EDT THU MAY 17 2012 TODAY...EXPECT THE BAND OF STRONGER 310K ISENTROPIC LIFT AND POSITION OF THE 750-650 MB WARM FRONT TO EXPAND TO THE ENE TODAY...PER NAM/GFS. HOWEVER...SINCE THE PCPN IS MOVING AWAY FROM THE GREATER LOW LEVEL MOISTURE INTO THE DRY LOW LEVEL AIRMASS TO THE EAST...PER 00Z MPX/INL/GRB SOUNDINGS...THE PCPN SHOULD REMAIN LIGHT AND MAINLY TO THE WEST AND SOUTH OF THE CWA. LOCATIONS FROM IWD-IMT WILL SEE THE BEST CHANCE OF ANY PCPN BUT ONLY SLIGHT CHANCE POPS WERE INCLUDED WITH ANY PCPN AMOUNTS LESS THAN A TENTH OF AN INCH. OTHERWISE...WAA WILL HELP PUSH TEMPS INTO THE MID 50S TO LOWER 70S DESPITE AN INCREASE IN MID HIGH CLOUDS. TONIGHT...THE FOCUS OF THE LLJ AND STRONGEST MOISTURE TRANSPORT IS EXPECTED OVER NE MN AND NW WI INTO WRN LAKE SUPERIOR. AREAS OF SHRA/TSRA SHOULD DEVELOP AND EVENTUALLY SPREAD TO THE EAST AFFECTING MAINLY THE NW HALF OF THE CWA AS THE LLJ VEERS OVERNIGHT. HOWEVER...THERE IS STILL SIGNIFICANT UNCERTAINTY WITH THE TIMING/POSITION OF THE CONVECTION. FRIDAY...ANY LEFTOVER SHRA/TSRA OVER MAINLY NORTH UPPER MI INTO LAKE SUPERIOR SHOULD SLIDE TO THE ENE AND DIMINISH DURING THE MORNING AS THE LLJ WEAKENS. THE COMBINATION OF BUILDING MID-LVL RDG HEIGHTS AND 850 MB WARM FRONT LIFTING WELL NORTH OF THE AREA SHOULD KEEP THE CWA DRY FRI AFTERNOON. RESIDUAL CLOUDS FROM CONVECTION SHOULD DISSIPATE FRI AFTERNOON ALLOWING FOR INCREASED SUNSHINE. MIXING OF 850 MB TEMPS OF AROUND 16C TO THE SFC SHOULD ALLOW FOR HIGH TEMPS FRIDAY TO REACH INTO THE LOWER 80S OVER WRN INTERIOR LOCATION. COOLER SRLY FLOW OFF LAKE MI WILL KEEP INLAND HIGHS OVER ERN COUNTIES IN THE LOW TO MID 70S. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 512 AM EDT THU MAY 17 2012 PERIOD STARTS 00Z SAT WITH A 500MB RIDGE OVER THE CWA...AND A 500MB TROUGH OVER THE INTERMOUNTAIN WEST. AT THE SFC...994MB LOW PRESSURE WILL BE STRETCHED E FROM ERN CO TO SRN ND...AND WITH HIGH PRESSURE SITTING OVER THE ERN SEABOARD...THAT PUTS US UNDER S/SSW FLOW. THAT/S RIGHT...WE WILL BE IN THE WARM SECTOR AS THE WARM FRONT ASSOCIATED WITH THE SYSTEM TO OUR W WILL BE N OF LAKE SUPERIOR BY 00Z SAT. AND WARM IT WILL BE WITH 850MB TEMPS AROUND 17C. FRI NIGHT AND SAT...SOLID S/SW FLOW IN THE WARM LOW LEVELS WILL KEEP TEMPS FROM FALLING TOO FAR FRI NIGHT...ESPECIALLY IN DOWNSLOPING AREAS. HAVE LOW TEMPS AROUND 60 IN THE DOWNSLOPE AREAS...AND IN THE UPPER 40S TO 50S ELSEWHERE. WITH HIGHER DEW PTS AND WAA...COULD SEE FOG OVER MAINLY NRN LAKE SUPERIOR AND EVENTUALLY NRN LAKE MI /WHICH WOULD LAST UNTIL FROPA SUNDAY/...WHICH I ADDED TO THE FORECAST FOR FRI NIGHT THROUGH SUN. 850MB TEMPS STAY AROUND 17C THROUGH SAT...WITH GOOD S/SW FLOW CONTINUING...ALLOWING MIXING TO AROUND 800MB. THIS YIELDS HIGH TEMPS IN THE 80S OVER THE W HALF AND NEAR LAKE SUPERIOR OVER THE E HALF...WITH HIGHS IN THE 60S CLOSE TO NRN LAKE MI DUE TO S/SSW FLOW OF THE RELATIVELY COLD LAKE. ATMOSPHERE LOOKS TOO DRY AND TOO CAPPED FOR CONVECTION TO FORM ON SAT...WHICH IS GOOD SINCE WE SHOULD HAVE 1500-2000J/KG OF CAPE SAT AFTERNOON. LOWERED DEW PTS A FEW DEGREES AS MIXING WILL ALLOW DRY AIR TO GET TO THE SFC. THIS LEADS TO MIN RH VALUES DOWN OF 25 TO 35 PERCENT OVER THE W HALF OF UPPER MI...AND GREATER THAN 35 PERCENT RH OVER THE E HALF. THIS BECOMES MORE PROBLEMATIC WHEN CONSIDERING WINDS WILL BE SLY AT 15-20MPH WITH GUSTS OF 25-35MPH. LOOKS LIKE IT MAY BE A CRITICAL FIRE WEATHER DAY...BUT THAT WILL NEED TO BE LOOKED AT MORE CLOSELY BY LATER SHIFTS FOR POSSIBLE FIRE WEATHER HEADLINES. SAT NIGHT THROUGH MON...BY 00Z SUN...THE UPPER TROUGH WILL HAVE MOVED FARTHER E...WITH A SHORTWAVE TROUGH OVER MANITOBA...AND POSSIBLY ANOTHER OVER KS/NE. THE SFC LOW WILL HAVE WEAKENED TO 1002MB AS IT MOVED TO N OF THE MN ARROWHEAD. THIS PUTS THE COLD JUST W OF LAKE SUPERIOR AT 00Z SUN. SAT NIGHT WILL BE ANOTHER WARM ONE WITH CONTINUED STRONG LOW LEVEL FLOW AND WARM LOW LEVEL TEMPS. OVERNIGHT LOWS LOOK TO BE IN THE 50S AND LOW 60S. DIFFERING MODEL SOLUTIONS BEGIN TO LOWER CONFIDENCE ON EXACT TIMING OF THE COLD FRONT/PRECIP DUE MAINLY WITH HOW TO HANDLE A SHORTWAVE MOVING AROUND THE MAIN UPPER TROUGH SAT NIGHT INTO SUN. THE GFS CONTINUES TO BE THE MOST AGGRESSIVE WITH THE SHORTWAVE...SHOWING IT STRONGER THAN PRETTY MUCH ANY OTHER MODEL. THIS MEANS THE GFS ALSO BRINGS THE COLD FRONT THROUGH FASTER THAN OTHER MODELS. FOR THIS REASON...WILL NOT PUT AS MUCH OF THE GFS INTO THIS FORECAST. WITH THE IDEA THAT THE GFS IS ABOUT 6 HOURS TOO FAST WITH FROPA...THE FRONT SHOULD MOVE OVER WRN UPPER MI SUN AFTERNOON...AND MOVE TO ERN UPPER MI BY 12Z MON...NOTE THE SLOW EASTWARD PROGRESSION OF THE FRONT. SBCAPES OF AROUND 1000-1500J/KG WILL BE POSSIBLE SUN AFTERNOON AHEAD OF THE FRONT...BUT CONFIDENCE IN THIS IS A BIT LOW RIGHT NOW DUE TO MODEL TIMING DIFFERENCES AND UNCERTAINTY IN HOW MUCH CLEARING WILL OCCUR AHEAD OF THE FRONT. 0-6KM BULK SHEAR LOOKS TO BE AROUND 30KTS...SUFFICIENT FOR ORGANIZED CONVECTION. SO...IT LOOKS LIKE SOME STRONG TO SEVERE STORMS WILL BE A POSSIBILITY SUN AFTERNOON/EVENING...BUT CONFIDENCE IS STILL LIMITED. THE COLD FRONT LOOKS TO COMPLETELY CLEAR THE CWA AROUND 18Z MON...AS THE UPPER TROUGH AND A SFC RIDGE MOVE INTO THE WRN CWA. 850MB TEMPS OF AROUND 7C MON AFTERNOON WILL MAKE FOR COOLER TEMPS IN THE 60S...EXCEPT IN THE 50S NEAR LAKE SUPERIOR IN THE NLY WINDS. MON NIGHT THROUGH WED...EXPECT A GRADUAL WARMING TREND AS AN UPPER RIDGE MOVES OVERHEAD AND SFC RIDGING SLOWLY MOVES TO E OF THE CWA BY WED AFTERNOON. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 729 AM EDT THU MAY 17 2012 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH THE PERIOD. MAIN ITEM OF CONCERN IS POTENTIAL SHOWERS APPROACHING KIWD TODAY. MUCH OF IT DEPENDS ON HOW AND WHERE SHOWERS OVER SOUTHERN MN WILL RIDE NE TOWARD WITH THE INCREASING SRLY FLOW TODAY. LIMITED CONFIDENCE ON THIS OCCURRING...SO WILL LEAVE OUT OF THE FORECAST GIVEN DRY LOW LEVELS. LLWS STILL EXPECTED AT ALL OF THE TAF SITES FOR THIS EVENING AND TONIGHT WITH THE STRONG LLVL JET MOVING OVER UPPER MI. MORE SHOWERS MAY APPROACH CMX TONIGHT...BUT AGAIN KEPT THOSE OUT OF THE FORECAST GIVEN DRY LOW LEVELS AND LIMITED CONFIDENCE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 512 AM EDT THU MAY 17 2012 WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SHIFT TO THE LOWER GREAT LAKES THIS AFTERNOON...BEFORE PUSHING OFF THE MID ATLANTIC SHORELINE ON FRIDAY INTO SATURDAY. LOW PRESSURE OVER SOUTHERN SASKATCHEWAN AND THE WESTERN DAKOTAS WILL PUSH ACROSS THE NORTHERN AND CENTRAL PLAINS TONIGHT THROUGH SATURDAY...BEFORE SLIDING NORTH INTO ONTARIO SATURDAY. THIS WILL ALLOW A COLD FRONT TO PUSH ACROSS THE UPPER GREAT LAKES SUNDAY INTO EARLY MONDAY. BEHIND THE FRONT...HIGH PRESSURE WILL BUILD IN FROM THE CENTRAL AND NORTHERN PLAINS THROUGH TUESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ006-007-013- 014-085. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...TITUS AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
516 AM EDT THU MAY 17 2012 .SYNOPSIS... ISSUED AT 512 AM EDT THU MAY 17 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM THE PLAINS INTO CNTRL CANADA AND A DOWNSTREAM TROUGH FROM QUEBEC INTO THE NE CONUS RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...HIGH PRES WAS CENTERED OVER LOWER MI WHILE LOW PRES WAS DEVELOPING OVER THE PLAINS FROM SRN SASK INTO WRN SOUTH DAKOTA. MID LEVEL WARM ADVECTION AHEAD OF A WARM FRONT OVER THE CNTRL PLAINS SUPPORTED DEVELOPING SHRA AND A FEW TSRA OVER SW MN. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 512 AM EDT THU MAY 17 2012 TODAY...EXPECT THE BAND OF STRONGER 310K ISENTROPIC LIFT AND POSITION OF THE 750-650 MB WARM FRONT TO EXPAND TO THE ENE TODAY...PER NAM/GFS. HOWEVER...SINCE THE PCPN IS MOVING AWAY FROM THE GREATER LOW LEVEL MOISTURE INTO THE DRY LOW LEVEL AIRMASS TO THE EAST...PER 00Z MPX/INL/GRB SOUNDINGS...THE PCPN SHOULD REMAIN LIGHT AND MAINLY TO THE WEST AND SOUTH OF THE CWA. LOCATIONS FROM IWD-IMT WILL SEE THE BEST CHANCE OF ANY PCPN BUT ONLY SLIGHT CHANCE POPS WERE INCLUDED WITH ANY PCPN AMOUNTS LESS THAN A TENTH OF AN INCH. OTHERWISE...WAA WILL HELP PUSH TEMPS INTO THE MID 50S TO LOWER 70S DESPITE AN INCREASE IN MID HIGH CLOUDS. TONIGHT...THE FOCUS OF THE LLJ AND STRONGEST MOISTURE TRANSPORT IS EXPECTED OVER NE MN AND NW WI INTO WRN LAKE SUPERIOR. AREAS OF SHRA/TSRA SHOULD DEVELOP AND EVENTUALLY SPREAD TO THE EAST AFFECTING MAINLY THE NW HALF OF THE CWA AS THE LLJ VEERS OVERNIGHT. HOWEVER...THERE IS STILL SIGNIFICANT UNCERTAINTY WITH THE TIMING/POSITION OF THE CONVECTION. FRIDAY...ANY LEFTOVER SHRA/TSRA OVER MAINLY NORTH UPPER MI INTO LAKE SUPERIOR SHOULD SLIDE TO THE ENE AND DIMINISH DURING THE MORNING AS THE LLJ WEAKENS. THE COMBINATION OF BUILDING MID-LVL RDG HEIGHTS AND 850 MB WARM FRONT LIFTING WELL NORTH OF THE AREA SHOULD KEEP THE CWA DRY FRI AFTERNOON. RESIDUAL CLOUDS FROM CONVECTION SHOULD DISSIPATE FRI AFTERNOON ALLOWING FOR INCREASED SUNSHINE. MIXING OF 850 MB TEMPS OF AROUND 16C TO THE SFC SHOULD ALLOW FOR HIGH TEMPS FRIDAY TO REACH INTO THE LOWER 80S OVER WRN INTERIOR LOCATION. COOLER SRLY FLOW OFF LAKE MI WILL KEEP INLAND HIGHS OVER ERN COUNTIES IN THE LOW TO MID 70S. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 512 AM EDT THU MAY 17 2012 PERIOD STARTS 00Z SAT WITH A 500MB RIDGE OVER THE CWA...AND A 500MB TROUGH OVER THE INTERMOUNTAIN WEST. AT THE SFC...994MB LOW PRESSURE WILL BE STRETCHED E FROM ERN CO TO SRN ND...AND WITH HIGH PRESSURE SITTING OVER THE ERN SEABOARD...THAT PUTS US UNDER S/SSW FLOW. THAT/S RIGHT...WE WILL BE IN THE WARM SECTOR AS THE WARM FRONT ASSOCIATED WITH THE SYSTEM TO OUR W WILL BE N OF LAKE SUPERIOR BY 00Z SAT. AND WARM IT WILL BE WITH 850MB TEMPS AROUND 17C. FRI NIGHT AND SAT...SOLID S/SW FLOW IN THE WARM LOW LEVELS WILL KEEP TEMPS FROM FALLING TOO FAR FRI NIGHT...ESPECIALLY IN DOWNSLOPING AREAS. HAVE LOW TEMPS AROUND 60 IN THE DOWNSLOPE AREAS...AND IN THE UPPER 40S TO 50S ELSEWHERE. WITH HIGHER DEW PTS AND WAA...COULD SEE FOG OVER MAINLY NRN LAKE SUPERIOR AND EVENTUALLY NRN LAKE MI /WHICH WOULD LAST UNTIL FROPA SUNDAY/...WHICH I ADDED TO THE FORECAST FOR FRI NIGHT THROUGH SUN. 850MB TEMPS STAY AROUND 17C THROUGH SAT...WITH GOOD S/SW FLOW CONTINUING...ALLOWING MIXING TO AROUND 800MB. THIS YIELDS HIGH TEMPS IN THE 80S OVER THE W HALF AND NEAR LAKE SUPERIOR OVER THE E HALF...WITH HIGHS IN THE 60S CLOSE TO NRN LAKE MI DUE TO S/SSW FLOW OF THE RELATIVELY COLD LAKE. ATMOSPHERE LOOKS TOO DRY AND TOO CAPPED FOR CONVECTION TO FORM ON SAT...WHICH IS GOOD SINCE WE SHOULD HAVE 1500-2000J/KG OF CAPE SAT AFTERNOON. LOWERED DEW PTS A FEW DEGREES AS MIXING WILL ALLOW DRY AIR TO GET TO THE SFC. THIS LEADS TO MIN RH VALUES DOWN OF 25 TO 35 PERCENT OVER THE W HALF OF UPPER MI...AND GREATER THAN 35 PERCENT RH OVER THE E HALF. THIS BECOMES MORE PROBLEMATIC WHEN CONSIDERING WINDS WILL BE SLY AT 15-20MPH WITH GUSTS OF 25-35MPH. LOOKS LIKE IT MAY BE A CRITICAL FIRE WEATHER DAY...BUT THAT WILL NEED TO BE LOOKED AT MORE CLOSELY BY LATER SHIFTS FOR POSSIBLE FIRE WEATHER HEADLINES. SAT NIGHT THROUGH MON...BY 00Z SUN...THE UPPER TROUGH WILL HAVE MOVED FARTHER E...WITH A SHORTWAVE TROUGH OVER MANITOBA...AND POSSIBLY ANOTHER OVER KS/NE. THE SFC LOW WILL HAVE WEAKENED TO 1002MB AS IT MOVED TO N OF THE MN ARROWHEAD. THIS PUTS THE COLD JUST W OF LAKE SUPERIOR AT 00Z SUN. SAT NIGHT WILL BE ANOTHER WARM ONE WITH CONTINUED STRONG LOW LEVEL FLOW AND WARM LOW LEVEL TEMPS. OVERNIGHT LOWS LOOK TO BE IN THE 50S AND LOW 60S. DIFFERING MODEL SOLUTIONS BEGIN TO LOWER CONFIDENCE ON EXACT TIMING OF THE COLD FRONT/PRECIP DUE MAINLY WITH HOW TO HANDLE A SHORTWAVE MOVING AROUND THE MAIN UPPER TROUGH SAT NIGHT INTO SUN. THE GFS CONTINUES TO BE THE MOST AGGRESSIVE WITH THE SHORTWAVE...SHOWING IT STRONGER THAN PRETTY MUCH ANY OTHER MODEL. THIS MEANS THE GFS ALSO BRINGS THE COLD FRONT THROUGH FASTER THAN OTHER MODELS. FOR THIS REASON...WILL NOT PUT AS MUCH OF THE GFS INTO THIS FORECAST. WITH THE IDEA THAT THE GFS IS ABOUT 6 HOURS TOO FAST WITH FROPA...THE FRONT SHOULD MOVE OVER WRN UPPER MI SUN AFTERNOON...AND MOVE TO ERN UPPER MI BY 12Z MON...NOTE THE SLOW EASTWARD PROGRESSION OF THE FRONT. SBCAPES OF AROUND 1000-1500J/KG WILL BE POSSIBLE SUN AFTERNOON AHEAD OF THE FRONT...BUT CONFIDENCE IN THIS IS A BIT LOW RIGHT NOW DUE TO MODEL TIMING DIFFERENCES AND UNCERTAINTY IN HOW MUCH CLEARING WILL OCCUR AHEAD OF THE FRONT. 0-6KM BULK SHEAR LOOKS TO BE AROUND 30KTS...SUFFICIENT FOR ORGANIZED CONVECTION. SO...IT LOOKS LIKE SOME STRONG TO SEVERE STORMS WILL BE A POSSIBILITY SUN AFTERNOON/EVENING...BUT CONFIDENCE IS STILL LIMITED. THE COLD FRONT LOOKS TO COMPLETELY CLEAR THE CWA AROUND 18Z MON...AS THE UPPER TROUGH AND A SFC RIDGE MOVE INTO THE WRN CWA. 850MB TEMPS OF AROUND 7C MON AFTERNOON WILL MAKE FOR COOLER TEMPS IN THE 60S...EXCEPT IN THE 50S NEAR LAKE SUPERIOR IN THE NLY WINDS. MON NIGHT THROUGH WED...EXPECT A GRADUAL WARMING TREND AS AN UPPER RIDGE MOVES OVERHEAD AND SFC RIDGING SLOWLY MOVES TO E OF THE CWA BY WED AFTERNOON. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 130 AM EDT THU MAY 17 2012 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH THE PERIOD. MAIN ITEM OF CONCERN IS POTENTIAL SHOWERS APPROACHING KIWD TOMORROW. MUCH OF IT DEPENDS ON SHOWERS DEVELOPMENT IN THE ERN DAKOTAS TONIGHT...WHICH WILL RIDE NE WITH THE INCREASING SRLY FLOW THROUGH THE DAY THURSDAY. LIMITED CONFIDENCE ON THIS OCCURRING...SO WILL LEAVE OUT OF THE FORECAST. ADDED IN LLWS TO ALL OF THE TAF SITES FOR TOMORROW EVENING WITH THE STRONG LLVL JET MOVING OVER UPPER MI. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 512 AM EDT THU MAY 17 2012 WINDS ACROSS LAKE SUPERIOR SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SHIFT TO THE LOWER GREAT LAKES THIS AFTERNOON...BEFORE PUSHING OFF THE MID ATLANTIC SHORELINE ON FRIDAY INTO SATURDAY. LOW PRESSURE OVER SOUTHERN SASKATCHEWAN AND THE WESTERN DAKOTAS WILL PUSH ACROSS THE NORTHERN AND CENTRAL PLAINS TONIGHT THROUGH SATURDAY...BEFORE SLIDING NORTH INTO ONTARIO SATURDAY. THIS WILL ALLOW A COLD FRONT TO PUSH ACROSS THE UPPER GREAT LAKES SUNDAY INTO EARLY MONDAY. BEHIND THE FRONT...HIGH PRESSURE WILL BUILD IN FROM THE CENTRAL AND NORTHERN PLAINS THROUGH TUESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ006-007-013- 014-085. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...TITUS AVIATION...KC MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
920 PM MDT FRI MAY 18 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY... A SURFACE HIGH BUILDING IN FROM THE NORTHWEST IS CLEARING SKIES FROM THAT DIRECTION. THEREFORE TRIMMED POPS IN THE WEST TO REFLECT THE LATEST RADAR TRENDS WHICH CORRESPOND TO GUIDANCE. ALSO MADE A FEW TWEAKS ON WINDS. THE REST OF THE FORECAST CONTINUES ON-TRACK. SCT PREVIOUS UPDATE... DID AN AN EARLY...PARTIAL UPDATE BASED ON RADAR TRENDS...MAINLY IN THE EASTERN ZONES...TO INCREASE POPS AND CHANGE WX TO AREAL COVERAGE FOR THIS EVENING. MOST RAIN SHOULD MOVE INTO NORTH DAKOTA AFTER MIDNIGHT BUT LEFT SMALL CHANCE POPS IN THE EAST. SCT PREVIOUS DISCUSSION... WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A FAIRLY ACTIVE AND PROGRESSIVE WEATHER PATTERN ACROSS THE CONUS. AREAS OF WEAK LOW PRESSURE ARE SETTING OFF SOME THUNDERSTORMS OVER THE SOUTHEASTERN STATES AND THE INTER-MOUNTAIN WESTERN STATES. WEAK HIGH PRESSURE HAS TAKEN CONTROL OVER THE MID MISSISSIPPI AND OHIO RIVER VALLEYS AND THE WEST COAST. THE ROCKY MOUNTAIN STORM SYSTEM WHICH BROUGHT MORE THAN A WETTING RAIN TO GLASGOW EARLY THIS MORNING CONTINUES TO MOVE SCATTERED RAIN SHOWERS THROUGH NORTHEAST MONTANA THIS AFTERNOON. SOME CLEARING FROM THE WEST HAS BEGUN TO EAT AWAY THE RAIN SHOWERS WHILE MORE ORGANIZED CONVECTION CONTINUES TO SUPPORT RAIN SHOWERS OF A MORE WIDESPREAD NATURE OVER OUR SOUTHEASTERN ZONES. HRRR AND NAM MODELS PICKED UP ON THIS SOUTHEASTERN PRECIP VERY WELL WHILE THE GFS IGNORED IT COMPLETELY. WOULD TEND TO LEAN A BIT AWAY FROM THE GFS FOR POPS AND QPF IN THE NEAR SHORT TERM WHILE THIS STORM SYSTEM MOVES AWAY TO WARD THE EAST TONIGHT. IN FACT...DURING THE LATE TONIGHT AND OVERNIGHT HOURS THERE SEEMS TO BE VERY GOOD MODEL AGREEMENT SHOWING THE EXITING SYSTEM BRINGING A SIGNIFICANT AMOUNT OF RAIN TO THE FAR SOUTHEASTERN CORNER OF OUR CWA. I MAY HAVE BEEN A LITTLE TOO CONSERVATIVE WITH QPF AND THAT MAY NEED TO BE INCREASED WITH AN UPDATE TONIGHT. BY SATURDAY MORNING...PRECIPITATION WILL HAVE MOVED COMPLETELY AWAY TO THE EAST OF OUR CWA AS THE UPPER LEVEL FLOW BECOMES MORE ZONAL AND VERY WEAK RIDGING TAKES OVER ACROSS THE REGION THROUGHOUT THE REMAINDER OF THE WEEKEND WITH MOSTLY CLEAR SKIES. THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND TO NORMAL AND ABOVE NORMAL LEVELS FOR THIS TIME OF YEAR. WIDESPREAD CLOUDINESS WILL AGAIN APPROACH FROM THE WEST BY LATE SUNDAY IN TIME TO HELP FILTER OUT THE ANNULAR SOLAR ECLIPSE NEAR SUNSET. BMICKELSON .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... NOT TOO MANY CHANGES WERE MADE TO GOING FORECAST AS PERIOD LOOKS RATHER UNSETTLED. DID INCREASE THEM SLIGHTLY FOR TUESDAY AS MOISTURE AND INSTABILITY POOL TO OUR SOUTHEAST AND MOVE IN ON RETURN SOUTH-SOUTHEAST FLOW. THE GFS CONTINUES TO KEEP THE AREA RATHER UNSETTLED AS A DEEP UPPER TROUGH SETS UP OVER THE WESTERN UNITED STATES. WILL KEEP MOSTLY CHANCE POPS GOING. JAMBA PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH ZONAL FLOW ALOFT THAT WILL BECOME A NARROW WAVE UPPER RIDGE ON MONDAY. THIS RIDGING WILL INCREASE THICKNESS HEIGHTS AND BEGIN A WARM-UP MONDAY...POSSIBLY LASTING THROUGH TUESDAY. MONDAY AFTERNOON AND EVENING A WEAK COLD FRONT FROM AN UPPER TROUGH DIGGING INTO THE PAC-NW WILL MOVE INTO MONTANA. THIS FRONT WILL INCREASE INSTABILITY...MAINLY OVER CENTRAL MONTANA. HOWEVER SOME THUNDERSTORMS COULD DRIFT INTO NORTHEAST MONTANA. THEN ON TUESDAY THE TROUGH SWINGS ACROSS THE NORTHERN ROCKIES SENDING ANOTHER STRONGER COLD FRONT INTO THE NORTHERN HIGH PLAINS. THERE ARE INDICATIONS OF EVEN GREATER INSTABILITY ON TUESDAY AND TUESDAY EVENING...FOR THE POSSIBILITY OF SEVERAL SEVERE THUNDERSTORMS THAT COULD MOVE INTO WESTERN NORTH DAKOTA FROM NE MONTANA. THE GFS AND EC DISAGREE ON HOW THE TROUGH DEVELOPS. BUT BOTH SEEM TO AGREE WITH THE TROUGH BECOMING MORE OF A LONG WAVE AND REMAINING OVER THE REGION THROUGH THE REST OF THE EXTENDED PERIOD...TRENDING TEMPERATURES TO BELOW AVERAGE BY THURSDAY AND FRIDAY. THE PERIOD WILL ALSO LIKELY SEE CONTINUING PERIODS OF SHOWER ACTIVITY. THE GFS CLOSES OFF THE LOW AND STACKS UP OVER WESTERN NORTH DAKOTA WEDNESDAY NIGHT...WHICH TENDS TO RETROGRADE PRECIPITATION BACK INTO NEMONT. THIS WOULD ALSO DEVELOP STRONG WINDS. THE EC ON THE OTHER HAND LIFTS THE CLOSED UPPER LOW INTO SOUTHERN ALBERTA AND SASKATCHEWAN. THEREFORE MODEL UNCERTAINTY WILL MAKE POPS AND QPF AMOUNTS DIFFICULT TO FORECAST. HOWEVER THE REST OF THE EXTENDED PERIOD SHOULD HAVE SHOWERS OR RAIN WITH THE COOLER TEMPERATURES. SCT && .AVIATION... SHOWERS CONTINUE EAST OF GLASGOW THIS EVENING AND SHOULD CONTINUE INTO THE OVERNIGHT HOURS. VFR CONDITIONS ARE EXPECTED THROUGH MIDNIGHT AND THEN POCKETS OF MVFR WILL DEVELOP FROM 09Z-15Z ACROSS THE EAST BEFORE CLEARING SKIES FOR SATURDAY. PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
703 PM MDT FRI MAY 18 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY... DID AN AN EARLY...PARTIAL UPDATE BASED ON RADAR TRENDS...MAINLY IN THE EASTERN ZONES...TO INCREASE POPS AND CHANGE WX TO AREAL COVERAGE FOR THIS EVENING. MOST RAIN SHOULD MOVE INTO NORTH DAKOTA AFTER MIDNIGHT BUT LEFT SMALL CHANCE POPS IN THE EAST. SCT PREVIOUS DISCUSSION... WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A FAIRLY ACTIVE AND PROGRESSIVE WEATHER PATTERN ACROSS THE CONUS. AREAS OF WEAK LOW PRESSURE ARE SETTING OFF SOME THUNDERSTORMS OVER THE SOUTHEASTERN STATES AND THE INTER-MOUNTAIN WESTERN STATES. WEAK HIGH PRESSURE HAS TAKEN CONTROL OVER THE MID MISSISSIPPI AND OHIO RIVER VALLEYS AND THE WEST COAST. THE ROCKY MOUNTAIN STORM SYSTEM WHICH BROUGHT MORE THAN A WETTING RAIN TO GLASGOW EARLY THIS MORNING CONTINUES TO MOVE SCATTERED RAIN SHOWERS THROUGH NORTHEAST MONTANA THIS AFTERNOON. SOME CLEARING FROM THE WEST HAS BEGUN TO EAT AWAY THE RAIN SHOWERS WHILE MORE ORGANIZED CONVECTION CONTINUES TO SUPPORT RAIN SHOWERS OF A MORE WIDESPREAD NATURE OVER OUR SOUTHEASTERN ZONES. HRRR AND NAM MODELS PICKED UP ON THIS SOUTHEASTERN PRECIP VERY WELL WHILE THE GFS IGNORED IT COMPLETELY. WOULD TEND TO LEAN A BIT AWAY FROM THE GFS FOR POPS AND QPF IN THE NEAR SHORT TERM WHILE THIS STORM SYSTEM MOVES AWAY TO WARD THE EAST TONIGHT. IN FACT...DURING THE LATE TONIGHT AND OVERNIGHT HOURS THERE SEEMS TO BE VERY GOOD MODEL AGREEMENT SHOWING THE EXITING SYSTEM BRINGING A SIGNIFICANT AMOUNT OF RAIN TO THE FAR SOUTHEASTERN CORNER OF OUR CWA. I MAY HAVE BEEN A LITTLE TOO CONSERVATIVE WITH QPF AND THAT MAY NEED TO BE INCREASED WITH AN UPDATE TONIGHT. BY SATURDAY MORNING...PRECIPITATION WILL HAVE MOVED COMPLETELY AWAY TO THE EAST OF OUR CWA AS THE UPPER LEVEL FLOW BECOMES MORE ZONAL AND VERY WEAK RIDGING TAKES OVER ACROSS THE REGION THROUGHOUT THE REMAINDER OF THE WEEKEND WITH MOSTLY CLEAR SKIES. THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND TO NORMAL AND ABOVE NORMAL LEVELS FOR THIS TIME OF YEAR. WIDESPREAD CLOUDINESS WILL AGAIN APPROACH FROM THE WEST BY LATE SUNDAY IN TIME TO HELP FILTER OUT THE ANNULAR SOLAR ECLIPSE NEAR SUNSET. BMICKELSON .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... NOT TOO MANY CHANGES WERE MADE TO GOING FORECAST AS PERIOD LOOKS RATHER UNSETTLED. DID INCREASE THEM SLIGHTLY FOR TUESDAY AS MOISTURE AND INSTABILITY POOL TO OUR SOUTHEAST AND MOVE IN ON RETURN SOUTH-SOUTHEAST FLOW. THE GFS CONTINUES TO KEEP THE AREA RATHER UNSETTLED AS A DEEP UPPER TROUGH SETS UP OVER THE WESTERN UNITED STATES. WILL KEEP MOSTLY CHANCE POPS GOING. JAMBA PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH ZONAL FLOW ALOFT THAT WILL BECOME A NARROW WAVE UPPER RIDGE ON MONDAY. THIS RIDGING WILL INCREASE THICKNESS HEIGHTS AND BEGIN A WARM-UP MONDAY...POSSIBLY LASTING THROUGH TUESDAY. MONDAY AFTERNOON AND EVENING A WEAK COLD FRONT FROM AN UPPER TROUGH DIGGING INTO THE PAC-NW WILL MOVE INTO MONTANA. THIS FRONT WILL INCREASE INSTABILITY...MAINLY OVER CENTRAL MONTANA. HOWEVER SOME THUNDERSTORMS COULD DRIFT INTO NORTHEAST MONTANA. THEN ON TUESDAY THE TROUGH SWINGS ACROSS THE NORTHERN ROCKIES SENDING ANOTHER STRONGER COLD FRONT INTO THE NORTHERN HIGH PLAINS. THERE ARE INDICATIONS OF EVEN GREATER INSTABILITY ON TUESDAY AND TUESDAY EVENING...FOR THE POSSIBILITY OF SEVERAL SEVERE THUNDERSTORMS THAT COULD MOVE INTO WESTERN NORTH DAKOTA FROM NE MONTANA. THE GFS AND EC DISAGREE ON HOW THE TROUGH DEVELOPS. BUT BOTH SEEM TO AGREE WITH THE TROUGH BECOMING MORE OF A LONG WAVE AND REMAINING OVER THE REGION THROUGH THE REST OF THE EXTENDED PERIOD...TRENDING TEMPERATURES TO BELOW AVERAGE BY THURSDAY AND FRIDAY. THE PERIOD WILL ALSO LIKELY SEE CONTINUING PERIODS OF SHOWER ACTIVITY. THE GFS CLOSES OFF THE LOW AND STACKS UP OVER WESTERN NORTH DAKOTA WEDNESDAY NIGHT...WHICH TENDS TO RETROGRADE PRECIPITATION BACK INTO NEMONT. THIS WOULD ALSO DEVELOP STRONG WINDS. THE EC ON THE OTHER HAND LIFTS THE CLOSED UPPER LOW INTO SOUTHERN ALBERTA AND SASKATCHEWAN. THEREFORE MODEL UNCERTAINTY WILL MAKE POPS AND QPF AMOUNTS DIFFICULT TO FORECAST. HOWEVER THE REST OF THE EXTENDED PERIOD SHOULD HAVE SHOWERS OR RAIN WITH THE COOLER TEMPERATURES. SCT && .AVIATION... SHOWERS CONTINUE EAST OF GLASGOW THIS EVENING AND SHOULD CONTINUE INTO THE OVERNIGHT HOURS. VFR CONDITIONS ARE EXPECTED THROUGH MIDNIGHT AND THEN POCKETS OF MVFR WILL DEVELOP FROM 09Z-15Z ACROSS THE EAST BEFORE CLEARING SKIES FOR SATURDAY. PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
919 PM CDT FRI MAY 18 2012 .UPDATE... UPDATED WIND FORECAST. WEATHER FORECAST ON TRACK. THUNDERSTORMS NOT PUTTING OUT MUCH IN WAY OF RAIN BUT SOME WIND AND MOSTLY SMALL HAIL. NUMEROUS LIGHTNING STRIKES WITH CLUSTER IN GARDEN GRANT AND ARTHUR COUNTIES. LOOKS TO BE JUST ENOUGH TREAT TO DIMINISH FIRE THREAT. && .PREV DISCUSSION... /ISSUED 842 PM CDT FRI MAY 18 2012/ AVIATION... STRONG STORMS MOVING ACROSS WESTERN NEBRASKA THIS EVENING. HAVE INCLUDED TEMPO GROUP FOR KVTN THROUGH 4Z. NORTHWEST WINDS BUILDING INTO THE NORTHWEST PANHANDLE. FROPA EXPECTED AT KVTN AROUND 1906Z AND KLBF 1911Z. STRATUS AND CEILINGS LOWERING INTO THE IFR CATEGORIES WITH DRIZZLE EXPECTED TO BUILD IN AFTER FROPA AND THEN LIGHT TO MODERATE RAIN DEVELOPING THROUGH THE AFTERNOON WITH CEILINGS LIFTING INTO MVFR. PREV DISCUSSION... /ISSUED 330 PM CDT FRI MAY 18 2012/ DISCUSSION... A POWERFUL UPPER LEVEL DISTURBANCE ACROSS COLO WILL MOVE SLOWLY EAST TONIGHT AND SATURDAY PRODUCING SCATTERED TSTMS...MAINLY ACROSS NORTH AND WEST PARTS OF THE FCST AREA WHICH WILL BE CLOSER TO THE BEST DYNAMICS. SUPER ENSEMBLE FCST QPF SUGGESTS AROUND 1/4 INCH OF RAIN NEAR NORTH PLATE AND CLOSE TO 3/4 OF AN INCH NEAR VALENTINE. FOR THIS EVENING THE THREAT OF HIGH BASED TSTMS CAPABLE OF GUSTY OR PERHAPS ISOLATED DAMAGING DOWNBURSTS WILL CONTINUE AS SFC RH IS OPERATING BELOW 40 PERCENT. ONCE THE COLD FRONT SWEEPS SOUTH LATER TONIGHT THE WIND THREAT SHOULD DIMINISH. THE ECM CONTINUES TO BE SLOWER WITH COLD FRONT HOLDING IT UP SOME SATURDAY AFTERNOON ACROSS THE ERN ZONES. THIS WAS INCORPORATED IN THE TEMP FORECAST FOR HIGHS IN THE 70S EAST...BUT UPPER 50S TO AROUND 60 WEST. THE UPPER LEVEL DISTURBANCE SHOULD CLEAR THE FCST AREA SATURDAY NIGHT WITH STRONG HIGH PRESSURE BUILDING IN SUNDAY FOR NEARLY CLEAR SKIES AND HIGHS IN THE 60S TO AROUND 70S. THE SFC HIGH WILL MOVE OFF EAST QUICKLY MONDAY WITH SOUTHERLY RETURN FLOW DEVELOPING AND A STRONG THERMAL RIDGE DEVELOPING ACROSS THE HIGH PLAINS AND CNTL ROCKIES BY LATE MONDAY AFTERNOON. THIS THERMAL RIDGE SHOULD MIGRATE EAST INTO THE NEB PANHANDLE TUESDAY AFTERNOON. MIX DOWN TOOLS FROM 700 MB SUGGESTS HIGHS IN THE LOWER 90S. FOR NOW 80S WILL OPERATE. ALL MODELS EXCEPT THE SLOWER AND VERY WARM GEM THEN SWEEP A COLD FRONT THROUGH WEDNESDAY LOWERING TEMPS ABOUT 10 DEGREES. THE FRONT WILL THEN LIFT SLOWLY NORTH THROUGH KS AND BECOME STATIONARY ACROSS SWRN NEB FRIDAY. ALL ALONG A DEEP UPPER LEVEL TROF WILL DROP INTO THE WRN U.S. AND WINDS ALOFT WILL BECOME SOUTHWEST AND INCREASE IN SPEED. SFC LOW PRESSURE WILL DEEPEN TO BELOW 990 MB ACROSS WRN KS SUPPORTING WINDY CONDITIONS...SHARP MOISTURE GRADIENTS AND A STRONG CAP...PERHAPS AS STRONG AS 12C ACROSS SRN NEB. GIVEN THE FAST FLOW ALOFT AND FOCUS OF THE SFC LOW...ISOLATED AND LOW-CHC POPS ARE IN PLACE LATE TUESDAY THROUGH THURSDAY. FIRE WEATHER... A FAIRLY SHARP DRYLINE HAS FORMED NEAR WRAY AND HOLYOKE COLO THIS AFTN WHERE RH IS RUNNING 11 TO 15 PERCENT. THE RUC SHOWS THIS DRYLINE PUSHING EAST INTO SWRN NEB LATE THIS AFTERNOON AS THE SFC LOW MOVES EAST TO NEAR BURLINGTON COLO. THE RED FLAG WARNING WILL CONTINUE IN EFFECT THIS EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/EXTENDED...CDC AVIATION...POWER
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
842 PM CDT FRI MAY 18 2012 .AVIATION... STRONG STORMS MOVING ACROSS WESTERN NEBRASKA THIS EVENING. HAVE INCLUDED TEMPO GROUP FOR KVTN THROUGH 4Z. NORTHWEST WINDS BUILDING INTO THE NORTHWEST PANHANDLE. FROPA EXPECTED AT KVTN AROUND 1906Z AND KLBF 1911Z. STRATUS AND CEILINGS LOWERING INTO THE IFR CATEGORIES WITH DRIZZLE EXPECTED TO BUILD IN AFTER FROPA AND THEN LIGHT TO MODERATE RAIN DEVELOPING THROUGH THE AFTERNOON WITH CEILINGS LIFTING INTO MVFR. && .PREV DISCUSSION... /ISSUED 330 PM CDT FRI MAY 18 2012/ DISCUSSION... A POWERFUL UPPER LEVEL DISTURBANCE ACROSS COLO WILL MOVE SLOWLY EAST TONIGHT AND SATURDAY PRODUCING SCATTERED TSTMS...MAINLY ACROSS NORTH AND WEST PARTS OF THE FCST AREA WHICH WILL BE CLOSER TO THE BEST DYNAMICS. SUPER ENSEMBLE FCST QPF SUGGESTS AROUND 1/4 INCH OF RAIN NEAR NORTH PLATE AND CLOSE TO 3/4 OF AN INCH NEAR VALENTINE. FOR THIS EVENING THE THREAT OF HIGH BASED TSTMS CAPABLE OF GUSTY OR PERHAPS ISOLATED DAMAGING DOWNBURSTS WILL CONTINUE AS SFC RH IS OPERATING BELOW 40 PERCENT. ONCE THE COLD FRONT SWEEPS SOUTH LATER TONIGHT THE WIND THREAT SHOULD DIMINISH. THE ECM CONTINUES TO BE SLOWER WITH COLD FRONT HOLDING IT UP SOME SATURDAY AFTERNOON ACROSS THE ERN ZONES. THIS WAS INCORPORATED IN THE TEMP FORECAST FOR HIGHS IN THE 70S EAST...BUT UPPER 50S TO AROUND 60 WEST. THE UPPER LEVEL DISTURBANCE SHOULD CLEAR THE FCST AREA SATURDAY NIGHT WITH STRONG HIGH PRESSURE BUILDING IN SUNDAY FOR NEARLY CLEAR SKIES AND HIGHS IN THE 60S TO AROUND 70S. THE SFC HIGH WILL MOVE OFF EAST QUICKLY MONDAY WITH SOUTHERLY RETURN FLOW DEVELOPING AND A STRONG THERMAL RIDGE DEVELOPING ACROSS THE HIGH PLAINS AND CNTL ROCKIES BY LATE MONDAY AFTERNOON. THIS THERMAL RIDGE SHOULD MIGRATE EAST INTO THE NEB PANHANDLE TUESDAY AFTERNOON. MIX DOWN TOOLS FROM 700 MB SUGGESTS HIGHS IN THE LOWER 90S. FOR NOW 80S WILL OPERATE. ALL MODELS EXCEPT THE SLOWER AND VERY WARM GEM THEN SWEEP A COLD FRONT THROUGH WEDNESDAY LOWERING TEMPS ABOUT 10 DEGREES. THE FRONT WILL THEN LIFT SLOWLY NORTH THROUGH KS AND BECOME STATIONARY ACROSS SWRN NEB FRIDAY. ALL ALONG A DEEP UPPER LEVEL TROF WILL DROP INTO THE WRN U.S. AND WINDS ALOFT WILL BECOME SOUTHWEST AND INCREASE IN SPEED. SFC LOW PRESSURE WILL DEEPEN TO BELOW 990 MB ACROSS WRN KS SUPPORTING WINDY CONDITIONS...SHARP MOISTURE GRADIENTS AND A STRONG CAP...PERHAPS AS STRONG AS 12C ACROSS SRN NEB. GIVEN THE FAST FLOW ALOFT AND FOCUS OF THE SFC LOW...ISOLATED AND LOW-CHC POPS ARE IN PLACE LATE TUESDAY THROUGH THURSDAY. AVIATION... SOUTH TO SOUTHEAST WINDS AT 15 TO 25 KTS...WILL SHIFT TO THE NORTH AFTER 06Z SATURDAY BEHIND A COLD FRONT. THE FRONT WILL MOVE THROUGH THE KVTN TAF SITE AROUND 06Z SATURDAY...AND INTO THE KLBF TAF SITE AREA AROUND 09Z SATURDAY. A FEW T-STORMS WILL BE POSSIBLE BOTH THIS EVENING AND OVERNIGHT WITH THE FRONTAL PASSAGE...BUT COVERAGE SHOULD REMAIN LIMITED AND WILL NOT INCLUDE IN THE OFFICIAL FORECAST AT THIS TIME. CONFIDENCE IS ALSO NOT HIGH ON ANY MVFR CEILINGS DUE TO STRATUS BEHIND THE FRONT. HAVE ALSO LEFT THIS OUT FOR NOW...AS CONDITIONS HAVE BEEN VERY DRY LATELY...AND NOT CERTAIN THE BOUNDARY LAYER WILL MOISTEN ENOUGH FOR STRATUS. FIRE WEATHER... A FAIRLY SHARP DRYLINE HAS FORMED NEAR WRAY AND HOLYOKE COLO THIS AFTN WHERE RH IS RUNNING 11 TO 15 PERCENT. THE RUC SHOWS THIS DRYLINE PUSHING EAST INTO SWRN NEB LATE THIS AFTERNOON AS THE SFC LOW MOVES EAST TO NEAR BURLINGTON COLO. THE RED FLAG WARNING WILL CONTINUE IN EFFECT THIS EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR NEZ210. && $$ SHORT TERM/EXTENDED...CDC AVIATION...POWER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
256 PM CDT THU MAY 17 2012 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...WINDY CONDITIONS HAVE DEVELOPED ACROSS MUCH OF THE FORECAST AREA TODAY AS DEEP MIXING HAS BEEN REALIZED ALONG WITH A TIGHTENING PRESSURE GRADIENT IN RESPONSE TO AN AREA OF SURFACE LOW PRESSURE TO OUR WEST. DO NOT EXPECT THESE WINDS TO DIMINISH RAPIDLY THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS AS PRESSURE GRADIENT WILL BE SLOW TO RELAX AND WINDS FROM ALOFT WILL NOT DECOUPLE UNTIL AFTER SUNSET...SO WENT AHEAD AN KEPT WIND ADVISORY GOING UNTIL 02Z THIS EVENING. IN ADDITION TO THE WINDS...THERE REMAINS A SLIGHT CHANCE FOR A FEW THUNDERSTORMS THIS EVENING ACROSS THE WESTERN FRINGES OF THE FORECAST AREA...AS FORCING FROM WELL DEFINED UPPER LEVEL LOW MAY HELP INITIATE A FEW STORMS. BOTH 12Z HRRR AND WRF HINT AT THIS TYPE OF DEVELOPMENT...BUT CONFIDENCE NOT HIGH ENOUGH TO INCREASE COVERAGE AS INSTABILITY REMAINS FAIRLY MARGINAL AND SIGNIFICANT COVERAGE IS NOT EXPECTED. IF STORMS DO DEVELOP HOWEVER...MAIN THREAT APPEARS TO BE VERY GUSTY WINDS AND SMALL HAIL. OVERNIGHT...THE COMBINATION OF A SCT-BKN CIRRUS SHIELD AND CONTINUED BREEZY SOUTHERLY WINDS SHOULD KEEP TEMPERATURES ELEVATED ABOVE SEASONAL LEVELS...WITH LOW TEMPERATURES STRUGGLING TO FALL TO NEAR 60 IN MOST LOCATIONS. WHILE DRY CONDITIONS ARE EXPECTED TO PREVAIL ON FRIDAY...ANOTHER WINDY DAY APPEARS TO BE IN STORE ACROSS THE REGION AS THE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE REGION AND ONCE AGAIN GOOD MIXING IS ANTICIPATED. WHILE A WIND ADVISORY MAY EVENTUALLY BECOME NECESSARY ACROSS THE EASTERN HALF OF THE FORECAST AREA DURING THE AFTERNOON HOURS...DECIDED TO HOLD OFF AT THIS POINT AS WE PRESENTLY ALREADY HAVE AN ADVISORY HIGHLIGHTED FOR TODAY. DID HOWEVER INCLUDE ADVISORY LEVEL WINDS FOR MUCH OF THE EASTERN HALF OF THE AREA DURING THE AFTERNOON HOURS TOMORROW IN LATEST GRIDS. IN ADDITION TO WINDS...EXPECT ANOTHER VERY WARM AFTERNOON FOR MID MAY...AND INCREASED AFTERNOON TEMPS SEVERAL DEGREES IN RESPONSE TO WARMING 850 MB TEMPS AND A WARM START TO THE DAY ANTICIPATED. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY. THE PRIMARY WEATHER FEATURES ARE A COLD FRONT THAT WILL TRACK ACROSS THE CWA ON SATURDAY AND THEN A WESTERN CONUS UPPER TROUGH THAT DEVELOPS BY THE MIDDLE OF NEXT WEEK. FRIDAY NIGHT...MOST FORECAST MODELS ARE DRY FOR OUR FORECAST AREA WITH THE BETTER CHANCE OF SHOWERS AND THUNDERSTORMS LOCATED ACROSS PORTIONS OF WESTERN AND NORTHERN NEBRASKA. WILL CONTINUE WITH A SLIGHT CHANCE OF THUNDERSTORMS ACROSS OUR NORTHWEST ZONES...PRIMARILY NORTHWEST OF A HOLDREGE TO GRAND ISLAND LINE. SATURDAY...THIS WILL BE OUR BEST CHANCE OF SEEING SHOWERS AND THUNDERSTORMS WITHIN THE NEXT 5 DAYS...OR AT LEAST THROUGH TUESDAY. AN UPPER LEVEL SHORT WAVE WILL SLIDE ACROSS THE CENTRAL PLAINS ACCOMPANIED BY A FAIRLY STRONG SFC COLD FRONT. THE MORNING SHOULD BE DRY...BUT SHOWERS AND THUNDERSTORMS WILL FORM ALONG AND BEHIND THE COLD FRONT BY MID TO LATE AFTERNOON. THE COLD FRONT WILL PRIMARILY TRACK ACROSS OUR CWA DURING THE AFTERNOON HOURS...BUT MAY NOT EXIT OUR FAR SOUTHEASTERN ZONES UNTIL AROUND OR A BIT AFTER SUNSET. THERE MAY BE TWO AREAS OF PRECIPITATION ASSOCIATED WITH THIS SYSTEM. THE FIRST WILL BE AN AREA OF STRATIFORM RAIN SHOWERS WITH GENERAL NON SEVERE THUNDERSTORMS WELL BEHIND THE FRONT. THE SECOND AREA WILL BE STRONG TO SEVERE THUNDERSTORMS THAT SHOULD FORM RIGHT ALONG OR VERY NEAR THE COLD FRONT. INSTABILITY WILL BE RATHER HIGH ALONG THE FRONT BY LATE AFTERNOON...ALTHOUGH THE WIND SHEAR WILL BE MORE MARGINAL AND UNIDIRECTIONAL. BULK SHEAR VECTORS ARE ORIENTED RATHER PARALLEL TO THE SFC COLD FRONT AND THERE SHOULD BE PRETTY GOOD FORCING RIGHT ALONG THE FRONT. CONSEQUENTLY...THUNDERSTORMS MAY TEND TO BE MORE LINEAR OR MULTI CELL RATHER THAN DISCRETE SUPERCELLS. THE PRIMARY THREAT WILL BE LARGE HAIL AND DAMAGING WINDS. HIGH TEMPERATURES SATURDAY WILL BE A DIFFICULT CALL AND GREATLY DEPEND ON THE PROGRESSION OF THE COLD FRONT AND CLOUD COVER. WOULD NOT BE SURPRISED TO SEE A FEW 90S ACROSS SOUTHEAST ZONES...WHILE NORTHWEST ZONES MAY STALL OUT IN THE UPPER 70S TO AROUND 80 BY EARLY AFTERNOON. TEMPERATURES MAY EVEN FALL A FEW DEGREES BY EARLY TO MID AFTERNOON FOR AREAS THAT SEE THE EARLIER FRONTAL PASSAGE. SUNDAY...GREAT DAY BEHIND THE COLD FRONT WITH DRY WEATHER AND HIGHS IN THE LOWER TO MID 70S MONDAY AND TUESDAY...EXPECT DRY WEATHER TO CONTINUE WITH A GRADUAL MODERATING TREND AS A WEAK UPPER RIDGE MOVES ACROSS AREA. HIGHS SHOULD CLIMB FROM THE 70S ON MONDAY BACK INTO THE 80S BY TUESDAY. WEDNESDAY AND THURSDAY...AN UPPER LEVEL TROUGH WILL DEEPEN ACROSS THE NORTHWESTERN CONUS AND MAY BEGIN TO ENHANCE THE FORCING/LIFT OVER THE CENTRAL PLAINS. THERE IS STILL A GOOD DEAL OF MODEL UNCERTAINTY WITH THIS SYSTEM AND HOW IT WILL EVOLVE AND PUSH OUT INTO THE PLAINS. THERE WILL BE AT LEAST SOME THREAT OF THUNDERSTORMS ACROSS THE CENTRAL OR NORTHERN PLAINS...BUT DIFFICULT TO GET INTO SPECIFICS AT THIS TIME GIVEN THE MODEL UNCERTAINTY. TEMPERATURES ARE MORE LIKELY TO BE ABOVE NORMAL IN THE 80S AHEAD OF THIS NEXT TROUGH. && .AVIATION...12Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE NEXT 24 HOURS...WITH LLWS PERSISTING THROUGH 14Z. THE COMBINATION OF A SHALLOW LOW LEVEL INVERSION AND A STRONG LOW LEVEL JET IS PROMOTING SIGNIFICANT LLWS STARTING AROUND 300FT AGL. THIS LLWS SHOULD DIMINISH BY 14Z AS DIABATIC HEATING ALLOWS FOR DEEPER BOUNDARY LAYER MIXING...THUS RESULTING IN STRONGER WINDS AT THE SURFACE AND LESS IN THE WAY OF LLWS. STRONG SURFACE WINDS WILL BE OBSERVED AT THE TERMINAL ONCE THE BOUNDARY LAYER BEGINS TO DEEPEN...WITH SUSTAINED SOUTHERLY WINDS OF 24KTS...GUSTING TO AROUND 34KTS...EXPECTED THIS AFTERNOON. SURFACE WINDS WILL THEN DIMINISH SOMEWHAT BY SUNSET AS DIABATIC HEATING IS LOST AND THE BOUNDARY LAYER DECOUPLES FROM THE STRONGER WINDS ALOFT. A SIMILAR SYNOPTIC SETUP MAY PROMOTE WEAK LLWS AGAIN TONIGHT...HOWEVER IT DOES NOT APPEAR AS THOUGH THE LOW LEVEL JET WILL BE QUITE AS STRONG TONIGHT AND WILL GO AHEAD AND LEAVE LLWS OUT OF THE TAF FOR THE TIME BEING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR NEZ060-061-072>074- 082>084. KS...WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR KSZ005-006-017-018. && $$ SHORT...ROSSI LONG...WESELY
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1100 PM EDT FRI MAY 18 2012 .SYNOPSIS... TROUGH OF LOW PRESSURE WILL REMAIN STALLED OFFSHORE TONIGHT BEFORE MOVING NORTHWEST TOWARD THE COAST ON SUNDAY. LOW PRESSURE WILL CONTINUE TO BRUSH THE COAST THROUGH EARLY NEXT WEEK...BRINGING RENEWED SHOWERS AND THUNDERSTORMS. THE LOW WILL MOVE NORTHEAST EARLY TUESDAY...WITH MORE TYPICAL WEATHER FOR THIS TIME OF YEAR EXPECTED BY MID-WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM FRIDAY...LATEST HRRR CONSOLIDATES THE BROAD SFC LOWS OFF THE CAROLINA COASTS TO 1 INTENSE CONCENTRIC LOOKING LOW JUST OFFSHORE FROM THE CAROLINA COASTS OVERNIGHT INTO SATURDAY. LATEST NAM ALSO FAVORS THIS SOLUTION. SO WITH EGG ON MY FACE...HAVE UPDATED THE ZONES WITH STRONGER NORTH TO NORTHEAST ACROSS THE FA WITH THE ADDITION OF GUSTS UP TO AND OVER 20 KT ACROSS THE COASTAL COUNTIES. BASED ON SURROUNDING 88DS INCLUDING OURS...THE CURRENT LOCATION OF THE SFC LOW IS ROUGHLY 85 MILES SOUTHEAST OF BALD HEAD ISLAND. LIGHT RAIN WILL CONTINUE TO TRACK WESTWARD AND PLAGUE THE COASTAL COUNTIES...WITH THE MAIN CONVECTION STAYING NEAR THE SFC LOW ITSELF. DO NOT ANTICIPATE ANY ONSHORE MOVEMENT OF THIS CONVECTION. IN ADDITION TO UPPING THE WINDS...HAVE LOWERED TONIGHTS MINS BY ATLEAST A CATEGORY. THIS BASED ON LATEST TEMP AND DEWPOINT TRENDS AND A QUICK LOOK-SEE AT THE 00Z MODEL GUIDANCE. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 2:45 PM FRIDAY...BROAD UPPER LOW NOW CENTERED DIRECTLY OVER THE COASTAL CAROLINAS WILL BE THE DRIVER FOR THE WEATHER IN THE SHORT TERM. VARIOUS MID-RANGE GUIDANCE IN GOOD ACCORD AS TO THE CHARACTER OF THE UPPER LOWS MOVEMENT...A SLOW SPIRAL OFFSHORE ON SATURDAY...THEN A DRIFT TO THE NORTHWEST AND ONSHORE ON SUNDAY. GUIDANCE A LITTLE LESS CLEAR AS TO THE PRECIPITATION CONSEQUENCES AND SURFACE REFLECTIONS FOR THIS FEATURE...ESPECIALLY ON SATURDAY. NAM IS THE WET SOLUTION WHILE ECMWF AND GFS KEEP THE EASTERN CAROLINAS ON THE DRY SIDE ON SATURDAY. HAVE LEANED MORE TOWARDS THE CONSENSUS DRYER SOLUTION FOR SATURDAY...WITH ISOLATED SHOWERS FOR THE COASTAL COUNTIES AND MINIMAL QPF...YET WITH EXTENSIVE CLOUD COVER. MORE AGREEMENT BETWEEN GUIDANCE AND HIGHER CONFIDENCE THAT SUNDAY WILL BE THE WETTER DAY AS THE UPPER LOW AND ITS SURFACE REFLECTION TRACK BACK NORTHWEST OVER LAND. OMEGA FIELDS SUGGEST WE COULD ALSO SEE THUNDERSTORMS DEVELOP SUNDAY AFTERNOON AND EVENING AS CORE OF UPPER LOW MOVES OVERHEAD. EXTENSIVE CLOUDINESS ON BOTH DAYS AND A STEADY NORTH TO NORTHEASTERLY FLOW THROUGH THE PERIOD WILL HELP KEEP DAYTIME TEMPERATURES BELOW NORMAL OVER THE WEEKEND...WITH HIGHS IN THE LOWER TO MID 70S ALONG THE COAST AND MID TO UPPER 70S INLAND. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...MID TO UPPER LOW SITTING DIRECTLY OVERHEAD EARLY MONDAY WILL LIFT OFF TO THE NORTHEAST MON NIGHT NIGHT INTO TUES AS ANOTHER SHORTWAVE TROUGH DIGS DOWN OVER THE SOUTHEAST. THIS TROUGH WILL PUSH A COLD FRONT THROUGH AREA TUES NIGHT INTO WED. DEPENDING ON TIMING OF EXITING LOW...WE SHOULD SEE A PERIOD OF SUBSIDENCE BEFORE NEXT SYSTEM COMES. AT THIS POINT IT LOOKS LIKE TUES MORNING MAY BE DRY WITH A BRIEF PERIOD OF DEEPER NW FLOW AND SUBSIDENCE ON BACK END OF LOW. PCP WATER DROPS FROM 1.8 INCHES DOWN TO JUST BELOW 1.5 INCHES BEFORE INCREASING AGAIN IN CONVECTION AHEAD OF COLD FRONT LATE TUES INTO EARLY WED. ONCE THIS FRONT CLEARS THE COAST ON WEDNESDAY...IT LOOKS LIKE WEAK HIGH PRESSURE WILL SETTLE OVER THE AREA THURS AND FRI WITH ONLY LOCALIZED SEA BREEZE CONVECTION POSSIBLE. DEEP DRY NORTHERLY FLOW ALOFT WILL VEER AROUND THURS THROUGH FRI WITH MOISTURE MAINLY CONFINED TO 5K FT AND BELOW FROM THURS INTO NEXT WEEKEND. WITH CLOUDS AND DEEP LAYER MOISTURE OVER AREA THE FIRST HALF OF THE WEEK...AND H5 HEIGHTS AROUND 575 DEM...EXPECT TEMPS TO REMAIN BELOW NORMAL UNTIL LOW LIFTS OFF AND FRONT PASSES BY ON WED. WARMING TREND WILL BEGIN WED WITH TEMPS REACHING ABOVE NORMAL AS RIDGE BUILDS OVER THE CAROLINAS FRI THROUGH NEXT WEEKEND. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...EXPECT VFR THROUGH VALID PERIOD...WITH EXCEPTION OF POTENTIAL MVFR DUE TO LOW CIGS EARLY SATURDAY MORNING. AS STALLED LOW PRESSURE SYSTEM CONTINUES TO SPIN OFF THE CAROLINA COAST...LIGHT ISOLATED SHOWERS CONTINUE TO MOVE ACROSS THE AREA...WITH MAJORITY OF RAINFALL JUST OFFSHORE AS DEPICTED BY CURRENT RADAR IMAGERY. OFFSHORE RAINFALL COULD POTENTIALLY MOVE ONSHORE THROUGH THE EARLY OVERNIGHT HOURS...BRINGING RAIN TO KILM. FOR NOW HAVE INTRODUCED TEMPO FOR THIS ACTIVITY THROUGH 3Z AT THE LATEST. OTHERWISE...EXPECT SCT/BKN HIGH LEVEL CLOUDS THROUGH THE OVERNIGHT HOURS...WITH NORTHEAST FLOW AOB 10 KTS CONTINUING. LOW LEVEL STRATUS AOA 1000FT COULD ADVECT INTO THE AREA JUST BEFORE SUNRISE...BUT ANTICIPATE ANY DEVELOPMENT TO BURN OFF BY MORNING. NORTHEAST FLOW WILL INCREASE AFTER DAYBREAK WITH SUSTAINED WINDS AOB 12 KTS THROUGHOUT THE DAY AND GUSTS NEAR 20 KTS. CANNOT RULE OUT ISOLATED TO SCATTERED SHOWERS DURING THE MORNING HOURS...ESPECIALLY AT THE COASTAL TERMINALS. THROUGHOUT THE DAY///MAY SEE SOME BREAKS IN THE CLOUDS...BUT OVERALL EXPECT SCT/BKN MID TO HIGH CLOUDS TO LINGER AS LOW PRESSURE STAYS JUST OFFSHORE. AFTER SUNSET...GUSTS WILL SUBSIDE ALLOWING FOR NORTHEAST FLOW AOB 10 KTS. EXTENDED OUTLOOK...MORNING STRATUS POSSIBLE THROUGH SUNDAY...MOSTLY OVER THE NORTHERN HALF OF THE CWA. POTENTIAL MVFR MONDAY AND TUESDAY. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1100 PM FRIDAY...STRONG SCA FOR ALL WATERS CONTINUES THROUGH SATURDAY AFTERNOON. HAVE UPPED WINDS ACROSS ALL WATERS BASED ON THE LATEST NAM/HRRR GUIDANCE WHICH ILLUSTRATE A CONSOLIDATED LOW. THE KLTX 88D INDICATES THIS LOW NOW 85 MILES SOUTHEAST OF BALD HEAD ISLAND. THE SFC PRESSURE PATTERN AND GRADIENT WILL YIELD NORTH TO NORTHEAST WINDS 15 TO 25 KT WITH GUSTS UP TO 30 KT INTO SATURDAY AFTERNOON. THE LATEST HRRR WIND OUTPUT NO LONGER LOOKS OVERDONE WITH 30 TO 40 KT SUSTAINED WINDS OFFSHORE AND CLOSER TO THE SFC LOW. CORRESPONDING SEAS WILL RANGE FROM 4 TO 7 FT...UP TO 8 AND 9 FT ACROSS THE OUTER WATERS OFF CAPE FEAR. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 2:45 PM FRIDAY...A GENERALLY NORTHERLY FLOW WILL PREVAIL THROUGH THE PERIOD AS A TROUGH OF LOW PRESSURE LINGERS EAST OF THE WATERS. LOW PRESSURE CENTERS DEVELOPING WITHIN THIS TROUGH WILL TIGHTEN GRADIENTS ENOUGH TO BUMP WINDS UP INTO THE 15 TO 20 KT RANGE THROUGH DAYTIME SUNDAY. WINDS WILL MODERATE LATER ON SUNDAY AS A LOW PRESSURE SYSTEM MOVES OVERHEAD. SEAS WILL BE HIGHEST EARLIEST IN THE PERIOD...WITH 6 FOOTERS LIKELY OVER THE OUTER FRINGES OF OUR WATERS. WILL KEEP SMALL CRAFT ADVISORY HEADLINES FOR DAYTIME SATURDAY AS A RESULT. OTHERWISE...SEE 3 TO 5 FT SEAS FOR MUCH OF THE SHORT TERM...WITH SEAS SUBSIDING LATE ON SUNDAY AS WINDS MODERATE. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...WINDS MAY BE A BIT TRICKY ON MONDAY AS LOW PRESSURE SITS OVERHEAD. MAY RETROGRADE JUST ENOUGH TO THE WEST TO PRODUCE A LIGHT S-SW FLOW. THIS LOW WILL LIFT OFF TO THE NORTHEAST LATE MON INTO EARLY TUES WITH A BRIEF VEERING OF THE WINDS BEFORE NEXT SYSTEM MOVES IN. THE WINDS SHOULD BACK AROUND THROUGH TUES AND INCREASE SLIGHTLY OUT OF THE W-SW AS COLD FRONT APPROACHES FROM THE NW. LOOKS LIKE THIS COLD FRONT WILL NOT MAKE A CLEAN SWEEP AND MAY BECOME WASHED OUT ACROSS THE AREA WITH WEAK GRADIENT FLOW SETTING UP BY THURS. WINDS WILL MOST LIKELY BE DRIVEN MORE BY LAND/SEA BREEZE BY THURS. OVERALL EXPECT WINDS 10 KTS OR LESS THROUGH MOST OF THE PERIOD...EXCEPT UP TO 15 KTS IN TIGHTENED GRADIENT FLOW LATE TUES THROUGH EARLY WED. SEAS WILL RUN 2 TO 3 FT EXCEPT ON TUES WHEN THEY INCREASE UP AROUND 4 FT IN OUTER WATERS TUES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252- 254-256. && $$ NEAR TERM...DCH SHORT TERM...REK LONG TERM...RGZ AVIATION...DRH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1012 PM EDT FRI MAY 18 2012 .SYNOPSIS... HIGH PRESSURE WILL EXTEND SOUTHWARD INTO THE CENTRAL CAROLINAS THROUGH THE WEEKEND...WHILE A LOW PRESSURE SYSTEM STALLS OUT AND MEANDERS JUST OFFSHORE THE CAROLINA COAST. && .NEAR TERM /TODAY THROUGH SATURDAY NIGHT/... AS OF 10 PM FRIDAY... TONIGHT: SURFACE HIGH PRESSURE CONTINUES TO BUILD/EXTEND INTO CENTRAL NC FROM THE NORTHEAST THIS EVENING... WHILE A GENERALLY STACK LOW PRESSURE SYSTEM IS LOCATED OFF THE COAST OF THE CAROLINAS. THIS SETUP AS ALLOWED DRIER AIR IN THE LOW LEVELS OF THE ATMOSPHERE TO FILTER INTO THE AREA IN MAINLY NORTH TO NORTHEASTERLY FLOW. MEANWHILE... MAINLY HIGH LEVEL CLOUD COVER IS STREAMING INTO THE AREA ALOFT FROM SHOWERS ANS STORMS THE OFFSHORE LOW PRESSURE SYSTEM. GIVEN THE RATHER DRY AIR CONTINUING TO BUILD INTO THE AREA IN THE LOW LEVELS OF THE ATMOSPHERE EXPECT DRY CONDITIONS FOR MOST IF NOT ALL OF THE CWA. THE ONE EXCEPTION MAY BE FROM A FEW VERY LIGHT SHOWERS SKIRTING SOUTHERN SAMPSON COUNTY THIS EVENING IN ASSOCIATED WITH THE OFFSHORE LOW. HOWEVER... GIVEN THE LATEST RAP SOUNDINGS FOR SOUTHERN SAMPSON COUNTIES STILL INDICATE A FAIRLY DRY SUB-CLOUD LAYER BELOW 750 MB (WITH A DRYING TREND BELOW 750 MB EXPANDING THROUGHOUT THE EVENING) WILL KEEP THE FORECAST DRY FOR THE ENTIRE AREA. THUS THE MAIN FORECAST PROBLEM CONTINUES TO BE THE HIGH LEVEL CLOUD COVER AND THE EFFECTS ON TEMPERATURES. HAVE INCREASED CLOUD COVER FROM THE PREVIOUS FORECAST AND INCREASED LOW A DEGREE OR TWO... GIVEN CURRENT OBSERVATIONAL DATA NAM AND GFS FORECAST SOUNDINGS. THIS YIELDS GENERALLY PARTLY TO MOSTLY CLOUDY SKIES FOR A GOOD PART OF THE NIGHT... WITH PERHAPS SOME MOSTLY CLEAR CONDITIONS ACROSS THE WESTERN/NORTHWESTERN PIEDMONT. THUS... WILL GO WITH LOW TEMPS GENERALLY IN THE LOWER TO MID 50S... WHICH IS NOW GENERALLY IN THE MIDDLE OF THE STATISTICAL GUIDANCE RANGE. SATURDAY AND SATURDAY NIGHT: THE AFOREMENTIONED UPPER LEVEL LOW AND ATTENDANT SURFACE LOW ARE PROGGED TO STALL JUST OFFSHORE THE CAROLINA COAST THROUGH 12Z SUNDAY MORNING. MODEL GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH THE PRECISE EVOLUTION OF THESE FEATURES...THOUGH NEITHER MODEL INDICATES MORE THAN A TRACE OF PRECIP IN THE FAR EAST/SE COASTAL PLAIN THROUGH SUNRISE SUNDAY MORNING. HOWEVER...THIS SYSTEM IS EXPECTED TO BECOME MORE PROGRESSIVE DURING THE DAY SUNDAY...RETROGRADING ONSHORE INTO EASTERN NC...AND IF THE SURFACE/UPPER LEVEL LOW RETROGRADE A BIT SOONER THAN CURRENTLY PROGGED...LIGHT SHOWERS WOULD BE POSSIBLE EAST OF THE I-95 CORRIDOR PRIOR TO SUNRISE SUNDAY MORNING. WITH THE ABOVE IN MIND...WILL KEEP THE FCST DRY ON SATURDAY...AND WILL INDICATE A SLIGHT CHANCE OF SHOWERS OR SPRINKLES IN THE COASTAL PLAIN AFTER MIDNIGHT. THE AIRMASS ACROSS CENTRAL NC WILL VARY FROM VERY DRY IN THE WESTERN PIEDMONT (0.50" PWAT AT GSO) TO MOIST IN THE COASTAL PLAIN (PWAT 1.15" AT RWI) ON SATURDAY. EXPECT SUNNY OR MOSTLY SUNNY SKIES IN THE WEST...AND PARTLY CLOUDY TO MOSTLY CLOUDY SKIES IN THE EAST. EXPECT HIGHS ON SATURDAY TO BE SLIGHTLY WARMER THAN TODAY IN THE WESTERN PIEDMONT (MID/UPPER 70S)...AND SIMILAR OR SLIGHTLY COOLER THAN TODAY IN THE FAR EASTERN COASTAL PLAIN (LOWER 70S). LOWS SAT NIGHT IN THE LOWER/MID 50S. -VINCENT && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 100 PM FRIDAY... THE FORECAST WILL HINGE ON THE EVENTUAL FATE/EVOLUTION OF THE MEANDERING CLOSED UPPER LOW AND ASSOCIATED LOW PRESSURE CENTER OFF THE NORTH CAROLINA COAST. OVERALL...THE GUIDANCE ENVELOPE HAS SHIFTED SLIGHTLY WESTWARD/INLAND FOR SUNDAY AND MONDAY...BUT THERE REMAINS SIGNIFICANT SPREAD WITH THE TIMING AND HOW FAR INLAND THIS SYSTEM WILL RETROGRADE. IF CURRENT TRENDS HOLD UP...EXPECT THICKENING CLOUD COVER WITH INCREASING RAIN CHANCES SUNDAY AFTERNOON/EVENING...AND CONTINUING INTO THE DAY ON MONDAY AS THE EASTERLY ATLANTIC MARITIME FEED WILL ADVECT HIGH PWATS ON THE ORDER 1.5-1.6"(2 SD ABOVE NORMAL)INLAND AS THE CIRCULATION CENTER WOBBLES WESTWARD OVER THE FORECAST AREA. EXPECT THAT WE WILL SEE A DIURNAL ENHANCEMENT IN POPS/CONVECTION... SUNDAY AFTERNOON/EVENING AND AGAIN MONDAY AFTERNOON BEFORE THE LOW BEGINS TO FINALLY TRANSLATE EASTWARD MONDAY EVENING/NIGHT WITH THE APPROACH OF THE NORTHERN STREAM TROUGH FROM THE WEST. THERE REMAINS TOO MUCH UNCERTAINTY AT THIS TIME TO DISCUSS IN DETAIL ABOUT ANY SEVERE/HEAVY RAIN THREAT...BUT WILL NEED TO MONITOR THE NEXT DAY OR TWO GIVEN RECENT HEAVY RAINS ACROSS CENTRAL AND EASTERN NC. FOR THE SAME REASONS...WILL KEEP POPS IN THE SLIGHT TO CHANCE CATEGORIES FOR NOW...WITH HIGHEST POPS IN THE EAST. WITH TIME...BUT IF LATER MODEL RUNS START TO EXHIBIT BETTER CONTINUITY... SUNDAY NIGHT AND INTO MONDAY COULD BE A WET PERIOD WITH LIKELY TO CATEGORICAL POPS. SEASONABLE TEMPERATURES SUNDAY THROUGH MONDAY...HIGHLY DEPENDENT ON THE UPPER LOW AND ASSOCIATED RAIN CHANCES. GIVEN THE WESTWARD TREND WITH THE LOW PRESSURE SYSTEM WILL NUDGE FORECAST HIGHS SUNDAY AND MONDAY DOWN A BIT...HIGHS GENERALLY IN THE MID TO UPPER 70S. LOWS 55 TO 60. -CBL && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 245 PM FRIDAY... THERE ARE SOME PRETTY GLARING DIFFERENCES WITH THE TIMING AND AMPLITUDE OF THE NEXT SHORTWAVE TROUGH AND ATTENDANT SURFACE FRONT MOVING EAST THROUGH THE REGION DURING THE TUESDAY THROUGH WEDNESDAY PERIOD. THE GFS IS UP TO ITS USUAL TRICKS/BIAS... RACING THE OPEN WAVE TROUGH EASTWARD THROUGH THE AREA TUESDAY EVENING/NIGHT...WHILE THE EC IS MORE SLOWER TO ADVANCE THE SYSTEM EASTWARD...DEVELOPING INTO A CLOSED LOW INVOF OF THE OHIO/TN VALLEY BEFORE FINALLY CROSSING THE AREA ON THURSDAY. UNTIL THERE IS BETTER MODEL AGREEMENT WILL BROAD BRUSH SLIGHT TO SMALL CHANCE POPS ACROSS THE AREA TUESDAY-WEDNESDAY WITH DRY CONDITIONS AFTERWORDS. MODERATING TEMPERATURES IN THE LOW-LEVEL SWLY FLOW. HIGHS IN THE LOWER TO MID 80S. LOWS IN THE 60S. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 745 PM FRIDAY... 24-HR TAF PERIOD: DESPITE CONSIDERABLE CLOUD COVERAGE OVER THE REGION ASSOCIATED WITH THE TROUGH ALONG THE CAROLINA COAST...MUCH OF THIS CLOUDINESS IS MID AND HIGH LEVEL WITH LOW CLOUDS CONFINED MAINLY ALONG THE COAST. GUIDANCE SHOWS LITTLE CHANGE OVERNIGHT THUS WILL CONTINUE WITH VFR CONDITIONS FEATURING BKN HIGH LAYER CLOUDS AND LIGHT NE SFC WINDS. LATER TONIGHT CAN`T RULE OUT A BRIEF PERIOD OF MVFR CIGS AT OUR EASTERN TAF SITES...BUT GIVEN CURRENT TRENDS THATS LOOKING LESS LIKELY NOW. AFTER SUNRISE SATURDAY...MODELS BEGIN TO SHOW THE SFC LOW OFF THE COAST BEGINNING TO GRADUALLY DRIFT WEST. THUS EXPECT THE NE WINDS TO PICK UP TO 10G20KT AND GRADUALLY INCREASING 3-5K FT CLOUDS ALONG OUR COASTAL PLAIN. LOOKING AHEAD: EXPECT INCREASING CHANCES FOR MVFR (PERHAPS IFR) CEILINGS SATURDAY NIGHT INTO SUNDAY MORNING AS THE AFOREMENTIONED SURFACE AND UPPER LEVEL LOW BEGINS TO RETROGRADE TOWARD THE COASTAL CAROLINAS... FOLLOWED BY INCREASING CHANCES FOR SHOWERS AND CONTINUED MVFR (PERHAPS IFR) CONDITIONS SUNDAY INTO SUNDAY NIGHT. THE RELATIVE WORSE CONDITIONS WOULD BE AT THE FAY/RWI TERMINALS...FOLLOWED BY RDU...AND FINALLY RWI. QUITE A BIT OF UNCERTAINTY PERSISTS IN THE FORECAST FOR EARLY NEXT WEEK...AND AT THIS TIME IT APPEARS THAT MVFR CONDITIONS AND CHANCES FOR SHOWERS WILL PERSIST THROUGH EARLY NEXT WEEK AND POSSIBLE INTO THE MIDDLE OF NEXT WEEK. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...BSD/VINCENT SHORT TERM...CBL LONG TERM...CBL AVIATION...NP/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
800 PM EDT FRI MAY 18 2012 .SYNOPSIS... TROUGH OF LOW PRESSURE WILL REMAIN STALLED OFFSHORE TONIGHT BEFORE MOVING NORTHWEST TOWARD THE COAST ON SUNDAY. LOW PRESSURE WILL CONTINUE TO BRUSH THE COAST THROUGH EARLY NEXT WEEK...BRINGING RENEWED SHOWERS AND THUNDERSTORMS. THE LOW WILL MOVE NORTHEAST EARLY TUESDAY...WITH MORE TYPICAL WEATHER FOR THIS TIME OF YEAR EXPECTED BY MID-WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 755 PM FRIDAY...LATEST HRRR CONSOLIDATES THE BROAD SFC LOW OFF THE CAROLINA COASTS TO 1 INTENSE CONCENTRIC LOOKING LOW JUST OFFSHORE FROM THE CAROLINA COASTS BY DAYBREAK SATURDAY. THIS SFC LOW LOOKS WELL OVERDONE INTENSITY-WISE BUT ITS LOCATION IS BELIEVABLE CONSIDERING IT IDENTIFIES THE CURRENT LOW OFFSHORE FROM CAPE FEAR AT INIT. TIME. BASED ON SURROUNDING 88DS INCLUDING OURS...WILL UP POPS ALONG THE IMMEDIATE COAST AND ATL WATERS. POPS WILL DECREASE CONSIDERABLY AS A SHARP GRADIENT EXTENDING INLAND. MODEL SOUNDINGS INDICATE THE POSSIBILITY OF LOW STRATUS LATE TONIGHT WITH AN OVERALL OVERCAST SKY. COULD OBSERVE A FEW BREAKS WEST OF THE I95 CORRIDOR IF ONE BELIEVES THE EUROPEAN MOISTURE PROFILE. CONTINUED WITH LATEST MIN TEMP FORECAST WHICH KEEPS THE FA AT OR SLIGHTLY ABOVE CLIMO. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 2:45 PM FRIDAY...BROAD UPPER LOW NOW CENTERED DIRECTLY OVER THE COASTAL CAROLINAS WILL BE THE DRIVER FOR THE WEATHER IN THE SHORT TERM. VARIOUS MID-RANGE GUIDANCE IN GOOD ACCORD AS TO THE CHARACTER OF THE UPPER LOWS MOVEMENT...A SLOW SPIRAL OFFSHORE ON SATURDAY...THEN A DRIFT TO THE NORTHWEST AND ONSHORE ON SUNDAY. GUIDANCE A LITTLE LESS CLEAR AS TO THE PRECIPITATION CONSEQUENCES AND SURFACE REFLECTIONS FOR THIS FEATURE...ESPECIALLY ON SATURDAY. NAM IS THE WET SOLUTION WHILE ECMWF AND GFS KEEP THE EASTERN CAROLINAS ON THE DRY SIDE ON SATURDAY. HAVE LEANED MORE TOWARDS THE CONSENSUS DRYER SOLUTION FOR SATURDAY...WITH ISOLATED SHOWERS FOR THE COASTAL COUNTIES AND MINIMAL QPF...YET WITH EXTENSIVE CLOUD COVER. MORE AGREEMENT BETWEEN GUIDANCE AND HIGHER CONFIDENCE THAT SUNDAY WILL BE THE WETTER DAY AS THE UPPER LOW AND ITS SURFACE REFLECTION TRACK BACK NORTHWEST OVER LAND. OMEGA FIELDS SUGGEST WE COULD ALSO SEE THUNDERSTORMS DEVELOP SUNDAY AFTERNOON AND EVENING AS CORE OF UPPER LOW MOVES OVERHEAD. EXTENSIVE CLOUDINESS ON BOTH DAYS AND A STEADY NORTH TO NORTHEASTERLY FLOW THROUGH THE PERIOD WILL HELP KEEP DAYTIME TEMPERATURES BELOW NORMAL OVER THE WEEKEND...WITH HIGHS IN THE LOWER TO MID 70S ALONG THE COAST AND MID TO UPPER 70S INLAND. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...MID TO UPPER LOW SITTING DIRECTLY OVERHEAD EARLY MONDAY WILL LIFT OFF TO THE NORTHEAST MON NIGHT NIGHT INTO TUES AS ANOTHER SHORTWAVE TROUGH DIGS DOWN OVER THE SOUTHEAST. THIS TROUGH WILL PUSH A COLD FRONT THROUGH AREA TUES NIGHT INTO WED. DEPENDING ON TIMING OF EXITING LOW...WE SHOULD SEE A PERIOD OF SUBSIDENCE BEFORE NEXT SYSTEM COMES. AT THIS POINT IT LOOKS LIKE TUES MORNING MAY BE DRY WITH A BRIEF PERIOD OF DEEPER NW FLOW AND SUBSIDENCE ON BACK END OF LOW. PCP WATER DROPS FROM 1.8 INCHES DOWN TO JUST BELOW 1.5 INCHES BEFORE INCREASING AGAIN IN CONVECTION AHEAD OF COLD FRONT LATE TUES INTO EARLY WED. ONCE THIS FRONT CLEARS THE COAST ON WEDNESDAY...IT LOOKS LIKE WEAK HIGH PRESSURE WILL SETTLE OVER THE AREA THURS AND FRI WITH ONLY LOCALIZED SEA BREEZE CONVECTION POSSIBLE. DEEP DRY NORTHERLY FLOW ALOFT WILL VEER AROUND THURS THROUGH FRI WITH MOISTURE MAINLY CONFINED TO 5K FT AND BELOW FROM THURS INTO NEXT WEEKEND. WITH CLOUDS AND DEEP LAYER MOISTURE OVER AREA THE FIRST HALF OF THE WEEK...AND H5 HEIGHTS AROUND 575 DEM...EXPECT TEMPS TO REMAIN BELOW NORMAL UNTIL LOW LIFTS OFF AND FRONT PASSES BY ON WED. WARMING TREND WILL BEGIN WED WITH TEMPS REACHING ABOVE NORMAL AS RIDGE BUILDS OVER THE CAROLINAS FRI THROUGH NEXT WEEKEND. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...EXPECT VFR THROUGH VALID PERIOD...WITH EXCEPTION OF POTENTIAL MVFR DUE TO LOW CIGS EARLY SATURDAY MORNING. AS STALLED LOW PRESSURE SYSTEM CONTINUES TO SPIN OFF THE CAROLINA COAST...LIGHT ISOLATED SHOWERS CONTINUE TO MOVE ACROSS THE AREA...WITH MAJORITY OF RAINFALL JUST OFFSHORE AS DEPICTED BY CURRENT RADAR IMAGERY. OFFSHORE RAINFALL COULD POTENTIALLY MOVE ONSHORE THROUGH THE EARLY OVERNIGHT HOURS...BRINGING RAIN TO KILM. FOR NOW HAVE INTRODUCED TEMPO FOR THIS ACTIVITY THROUGH 3Z AT THE LATEST. OTHERWISE...EXPECT SCT/BKN HIGH LEVEL CLOUDS THROUGH THE OVERNIGHT HOURS...WITH NORTHEAST FLOW AOB 10 KTS CONTINUING. LOW LEVEL STRATUS AOA 1000FT COULD ADVECT INTO THE AREA JUST BEFORE SUNRISE...BUT ANTICIPATE ANY DEVELOPMENT TO BURN OFF BY MORNING. NORTHEAST FLOW WILL INCREASE AFTER DAYBREAK WITH SUSTAINED WINDS AOB 12 KTS THROUGHOUT THE DAY AND GUSTS NEAR 20 KTS. CANNOT RULE OUT ISOLATED TO SCATTERED SHOWERS DURING THE MORNING HOURS...ESPECIALLY AT THE COASTAL TERMINALS. THROUGHOUT THE DAY///MAY SEE SOME BREAKS IN THE CLOUDS...BUT OVERALL EXPECT SCT/BKN MID TO HIGH CLOUDS TO LINGER AS LOW PRESSURE STAYS JUST OFFSHORE. AFTER SUNSET...GUSTS WILL SUBSIDE ALLOWING FOR NORTHEAST FLOW AOB 10 KTS. EXTENDED OUTLOOK...MORNING STRATUS POSSIBLE THROUGH SUNDAY...MOSTLY OVER THE NORTHERN HALF OF THE CWA. POTENTIAL MVFR MONDAY AND TUESDAY. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 8 PM FRIDAY...SCA FOR ALL WATERS CONTINUES INTO SATURDAY AFTERNOON. WILL CONTINUE WITH THE CURRENT WIND REGIME WHICH HIGHLIGHTS A SFC PRESSURE PATTERN AND GRADIENT THAT YIELDS N TO NE WINDS 15 TO 25 KT OVERNIGHT INTO SATURDAY. THE LATEST HRRR WIND OUTPUT LOOKS WAY OVERDONE WITH 30 TO 40 KT SUSTAINED JUST OFFSHORE FROM CAPE FEAR. WILL FORECAST SEAS RANGING FROM 3 TO 6 FT...WITH THE HIGHER SEAS ACROSS THE OUTER WATERS OFF CAPE FEAR. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 2:45 PM FRIDAY...A GENERALLY NORTHERLY FLOW WILL PREVAIL THROUGH THE PERIOD AS A TROUGH OF LOW PRESSURE LINGERS EAST OF THE WATERS. LOW PRESSURE CENTERS DEVELOPING WITHIN THIS TROUGH WILL TIGHTEN GRADIENTS ENOUGH TO BUMP WINDS UP INTO THE 15 TO 20 KT RANGE THROUGH DAYTIME SUNDAY. WINDS WILL MODERATE LATER ON SUNDAY AS A LOW PRESSURE SYSTEM MOVES OVERHEAD. SEAS WILL BE HIGHEST EARLIEST IN THE PERIOD...WITH 6 FOOTERS LIKELY OVER THE OUTER FRINGES OF OUR WATERS. WILL KEEP SMALL CRAFT ADVISORY HEADLINES FOR DAYTIME SATURDAY AS A RESULT. OTHERWISE...SEE 3 TO 5 FT SEAS FOR MUCH OF THE SHORT TERM...WITH SEAS SUBSIDING LATE ON SUNDAY AS WINDS MODERATE. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...WINDS MAY BE A BIT TRICKY ON MONDAY AS LOW PRESSURE SITS OVERHEAD. MAY RETROGRADE JUST ENOUGH TO THE WEST TO PRODUCE A LIGHT S-SW FLOW. THIS LOW WILL LIFT OFF TO THE NORTHEAST LATE MON INTO EARLY TUES WITH A BRIEF VEERING OF THE WINDS BEFORE NEXT SYSTEM MOVES IN. THE WINDS SHOULD BACK AROUND THROUGH TUES AND INCREASE SLIGHTLY OUT OF THE W-SW AS COLD FRONT APPROACHES FROM THE NW. LOOKS LIKE THIS COLD FRONT WILL NOT MAKE A CLEAN SWEEP AND MAY BECOME WASHED OUT ACROSS THE AREA WITH WEAK GRADIENT FLOW SETTING UP BY THURS. WINDS WILL MOST LIKELY BE DRIVEN MORE BY LAND/SEA BREEZE BY THURS. OVERALL EXPECT WINDS 10 KTS OR LESS THROUGH MOST OF THE PERIOD...EXCEPT UP TO 15 KTS IN TIGHTENED GRADIENT FLOW LATE TUES THROUGH EARLY WED. SEAS WILL RUN 2 TO 3 FT EXCEPT ON TUES WHEN THEY INCREASE UP AROUND 4 FT IN OUTER WATERS TUES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252- 254-256. && $$ NEAR TERM...DCH SHORT TERM...REK LONG TERM...RGZ AVIATION...DRH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
645 PM CDT FRI MAY 18 2012 .DISCUSSION... AS OF 2330 UTC...THE CONVECTIVE ACTIVITY THAT INITIATED IN THE BISMARCK...MANDAN VICINITY WAS QUICKLY EXITING THE CWA INTO NORTHEAST NORTH DAKOTA...WITH AN AREA OF LIGHT RAIN ACROSS THE NORTHWEST IN ASSOCIATION WITH A SURFACE TROUGH AND BETTER FORCING FROM THE UPPER LEVEL WAVE. FURTHER EAST...A COLD FRONT WAS LOCATED FROM FAR NORTHWEST MINNESOTA...PASSING IN BETWEEN JAMESTOWN AND VALLEY CITY EXTENDING INTO SOUTH CENTRAL SOUTH DAKOTA. THE 23 UTC SPC MESOANALYSIS DEPICTED 1000-1500 J/KG OF ML CAPE CENTERED JUST ON THE COOL SIDE OF THE FRONT ACROSS NORTH DAKOTA WITH 35-40 KTS OF DEEP LAYER SHEAR. HOWEVER...CINH HAS ALSO INCREASED OVER THE PAST HOUR. THERE MAY BE A BRIEF WINDOW BEFORE SUNSET FOR SURFACE BASED INITIATION ALONG THE BOUNDARY...HOWEVER...CONFIDENCE IS DECREASING AS SUPPORTED BY THE LATEST HRRR RUNS. THE BEST PRECIPITATION CHANCES FOR WESTERN AND CENTRAL NORTH DAKOTA SHOULD COME AFTER 06 UTC AS CONVECTION ACROSS SOUTHWEST SOUTH DAKOTA AND INTO NEBRASKA LIFTS NORTHEAST AND CONGEALS. INCREASED POPS ALONG AND EAST OF HIGHWAY 85 TO 100 PERCENT FOR MOST AREAS. THE BEST CHANCES FOR THUNDER POST 06 UTC WILL BE ACROSS THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY WHERE THE BEST ELEVATED CAPE WILL RESIDE. FURTHER WEST...BUFR SOUNDINGS INDICATED NEARLY SATURATED PROFILES WITH LITTLE CAPE AND WEAKENING MID LEVEL LAPSE RATES...MORE SUPPORTIVE OF MODERATE TO HEAVY RAIN. && .AVIATION... AS OF 2330 UTC...A COLD FRONT WAS LOCATED FROM NEAR KHCO HALLOCK MINNESOTA TO JUST EAST OF KJMS THROUGH SOUTH CENTRAL SOUTH DAKOTA. THERE IS DECREASING CONFIDENCE FOR STORMS TO INITIATE ALONG THIS FRONT BEFORE SUNSET IN NORTH DAKOTA...WITH THE BEST CHANCES FOR PRECIPITATION AFTER 06 UTC AS SHOWERS AND STORMS ACROSS SOUTH DAKOTA AND NEBRASKA LIFT NORTHEAST. MVFR CEILINGS ARE POSSIBLE IN WIDESPREAD RAIN SHOWERS TONIGHT ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH EMBEDDED THUNDERSTORMS ACROSS THE CENTRAL. WINDS WILL TRANSITION TO THE NORTHWEST TONIGHT WITH GUSTS TO 25 KTS POSSIBLE BY 12 UTC AT ALL TAF SITES. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1035 PM EDT FRI MAY 18 2012 .SYNOPSIS... A WARM AND TRANQUIL WEEKEND IS IN STORE FOR THE AREA AS A DEEP LAYERED RIDGE OF HIGH PRESSURE MOVES ACROSS OHIO INTO INTERIOR NEW ENGLAND BY LATER ON SUNDAY. WEAK EASTERLY FLOW AT THE SURFACE WILL HOLD DEEPER MOISTURE AT BAY...BUT HUMIDITIES WILL BE ON THE INCREASE OVER WHAT HAS BEEN EXPERIENCED THE PREVIOUS FEW DAYS. A WEAKENING WEATHER SYSTEM SHIFTING THROUGH THE WESTERN GREAT LAKES SUNDAY NIGHT WILL SLOW AS IT MOVES INTO THE OHIO VALLEY...BRINGING THE NEXT THREAT OF SHOWERS AND THUNDERSTORMS. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... DESPITE VERY WEAK NEAR-SURFACE WIND FLOW...MOISTURE IS INCREASING FROM SOUTHEAST TO NORTHWEST ACROSS THE FORECAST AREA AT THIS TIME. WITH THE MOSTLY CALM WINDS AND CLEAR SKIES...SOME FOG SEEMS LIKELY IN PRONE AREAS...AND PATCHY REDUCED VISIBILITIES ARE POSSIBLE ELSEWHERE AS WELL. ADDED SLIGHTLY MORE LOW-ELEVATION FOG THAN THE PREVIOUS FORECAST...AND MADE SOME MINOR ADJUSTMENTS TO MIN TEMPS AS WELL. PREVIOUS DISCUSSION > AMPLE SUNSHINE AGAIN TODAY WITH LOW DEWPOINTS /30S AND 40S/...THANKS TO DEEP LAYERED RIDGE OF HIGH PRESSURE OVER THE AREA. 18.19Z RUC ANALYSIS INDICATED A CLOSED-CONTOUR 580DM ANTICYCLONE OVER NRN INDIANA...ATOP A CLOSED-CONTOUR 576DM CYCLONE JUST OFF THE SOUTH CAROLINA COAST. NOT OVER STRONG/IMPRESSIVE SYSTEMS...BUT THIS REX BLOCK TYPE STRUCTURE WILL CONTINUE TO DOMINATE OUR WEEKEND WEATHER PATTERN...WITH WEAK EASTERLY FLOW OUT OF A SURFACE HIGH PRESSURE SYSTEM IN NEW ENGLAND /RATHER BAGGY PRESSURE GRADIENT/ CONTINUING TO HOLD DEEPER BOUNDARY LAYER MOISTURE /60S DEWPOINTS/ WELL SOUTH AND WEST OF THE AREA. IN THE UPCOMING 12-15 HOURS...EXPECT VERY LITTLE SYNOPTIC SCALE CHANGE AS THE MID-LEVEL HIGH DRIFTS THROUGH NRN OHIO AND STRENGTHENS SLIGHTLY WHILE THE LOW OVER THE WRN ATL ELONGATES SOME BEGINS SPLITTING INTO TWO DISTINCT CYCLONIC CIRCULATION CENTERS...ONE IN ERN GA AND THE OTHER OFF THE NC COAST. VERY WEAK SFC FLOW WILL QUICKLY GO CALM THIS EVENING UNDER RAPIDLY STRENGTHENING INVERSION AND DECOUPLING OF THE SHALLOWING BOUNDARY LAYER. THIS SHOULD FOSTER A RAPID EVENING TEMP DROP WITH CLEAR SKIES. RAN A GENERAL BLEND OF THE PREVIOUS FORECAST AND 12Z ECMWF/GFS/NAM MOS...THOUGH TWEAKED A TOUCH DOWNWARD IN THE COOL SPOTS GIVEN IDEAL RADIATIONAL COOLING REGIME. ALSO FOGGED UP THE OHIO AND ADJACENT RIVER VALLEYS LATER IN THE NIGHT...AS BOUNDARY LAYER MOISTURE FROM KY WILL BE SEEPING NWRD OVERNIGHT AS MINOR SLY COMPONENT TO THE GENERAL EASTERLY FLOW WILL ALLOW AN INCREASE IN LLVL MOISTURE. WOULD NOT BE SURPRISED IS FOG BECOMES A LITTLE MORE WIDESPREAD THAN FORECAST ESP OVER NRN KY/SRN OH/SERN IND. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... VERY LITTLE CHANGE TO THE PATTERN ALOFT ON SATURDAY...THOUGH THE LOW LEVELS WILL BEGIN TO UNDERGO SOME MOISTURE ADVECTION...ESPECIALLY ACROSS SRN/SWRN FORECAST AREA. 18.12Z WRF/GFS INDICATE LOWEST 1KM SPECIFIC HUMIDITIES DOUBLING IN COMPARISON TO FRIDAY...SO BROUGHT DEWPOINTS UP A BIT IN THE SOUTH/SOUTHWEST...PERHAPS NOT ENOUGH. FEEL 18.12Z NAM-WRF SFC DWPTS ABOUT 10F TOO HIGH AS HAS BEEN A PROBLEM THIS SPRING...SO DISCOUNTING THE RATHER STRONG INSTBY THAT DEVELOPS UNDERNEATH THE MID LEVEL RIDGE SATURDAY AFTERNOON. EVEN SO...ADDITIONAL MOISTURE AND A FAVORABLE LAPSE RATE WILL NO DOUBT YIELD SOME DEEPER CUMULUS ACROSS THE SOUTH/SOUTHWEST...BUT THINK NIL FORCING AND CONTINUED RISING HEIGHTS WILL MITIGATE A NEED FOR A RAIN CHANCE AT THIS TIME. A WARM DAY...AND MOS SHOULD PERFORM WELL IN THIS RATHER PREDICTABLE REGIME...SO AGAIN BLENDED PREVIOUS FORECAST WITH MOST RECENT VALUES. SPOT CHECK OF LOW LEVEL THICKNESS CONSIDERATIONS AND MIXING TO 850-825MB /DESPITE VERY WEAK FLOW/ SUGGESTS WIDESPREAD LOWER TO MIDDLE 80S...VERY MUCH IN LINE WITH THE BLEND. LIKELY A REPEAT SCENARIO SATURDAY NIGHT WITH VALLEY FOG...AND LOWS IN THE 50S. SUNDAY IS A CARBON-COPY OF SATURDAY. DISTINCT CIRCULATION CENTERS ATTENDANT TO THE SOUTHEAST CONUS TROUGH RECOMBINE OVER THE OUTER BANKS OF NC WHILE THE MID LEVEL ANTICYCLONE CONTINUES TO DEEPEN TO 585DM OVER INTERIOR NEW ENGLAND. THIS WILL REINFORCE A LOW LEVEL EASTERLY TRAJECTORY...THUS DON/T EXPECT MUCH /IF ANY/ DEWPOINT RISE ON SUNDAY...AND TEMPERATURES SHOULD HOLD VERY SIMILAR TO SATURDAY/S READINGS. PROBABLY A THICKER CIRRUS SHIELD PER BUFR SOUNDINGS...BUT THAT WOULD BE ABOUT THE EXTENT OF SENSIBLE WEATHER. SUNDAY NIGHT BEGINS TO SEE SOME CHANGE AS A TROUGH OF LOW PRESSURE /DAMPENING OUT AND SLOWING AS IT ENCOUNTERS THE BLOCKY FLOW ALONG THE EAST COAST/ APPROACHES THE GREAT LAKES. HAVE KEPT THE NIGHTTIME DRY AT THIS POINT AS 18.12Z GUIDANCE WAFFLING ON WEAK/MID LEVEL- BASED SHOWERS AND STORM PLACEMENT AS FORCING SLOWLY INCREASES LATER IN THE NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... PERIOD OF DRY WEATHER MAY COME TO AN END MONDAY AS MOISTURE AND INSTABILITY INCREASE AHEAD OF AN UPPER TROUGH. WITH THE ECMWF AND GFS COMING INTO FAIR AGREEMENT...KEPT A CHANCE OF THUNDERSTORMS FOR MONDAY...MAINLY IN WESTERN COUNTIES THAT WILL BE AFFECTED MORE BY SURFACE CONVERGENCE AND COOLER AIR ALOFT. STAYED CLOSE TO ECMWF SOLUTION FOR TUESDAY SINCE IT CONTINUES TO SHOW A CLOSED UPPER LOW FORMING AS OPPOSED TO THE FASTER OPEN WAVE DEPICTED ON THE GFS. AS THE UPPER LOW FORMS NEAR CVG...THERE WILL BE A GOOD CHANCE FOR THUNDERSTORMS UNDER A COOL POOL ALOFT COUPLED WITH DEEP MOISTURE ADVECTION FROM THE SOUTH. THUNDERSTORMS CHANCES WILL DIMINISH ON WEDNESDAY AS THE CLOSED UPPER LOW SLIPS EAST ALLOWING DRIER AND MORE STABLE AIR TO WORK IN. THE DRY CONDITIONS ARE EXPECTED TO CONTINUE ON THURSDAY AND FRIDAY WHEN RIDGING ALOFT IS FORECAST TO MOVE BACK IN. HIGH TEMPERATURES WILL BE MAINLY IN THE 80S MONDAY ON THE EAST SIDE OF THE UPPER TROUGH. COOLER READINGS IN THE 70S ARE FORECAST AS THE CLOSED LOW MAKES ITS WAY ACROSS THE AREA WITH ASSOCIATED CLOUD COVER AND COLD ADVECTION. LOOK FOR A REBOUND TO THE 80S BY FRIDAY AS SUNSHINE AND WARM ADVECTION RETURN. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE WILL MAINTAIN CONTROL OF THE WEATHER THROUGH THE TAF PERIOD. LOW LEVEL MOISTURE WILL BE INCREASING OVER THE NEXT DAY OR SO...WHICH WILL ALLOW FOR SOME CUMULUS DEVELOPMENT TOMORROW. OVERNIGHT TONIGHT...IT MAY ALLOW FOR SOME FOG TO DEVELOP AT THE CINCINNATI TAF SITES (INCLUDING LIFR AT KLUK). WINDS WILL REMAIN FAIRLY LIGHT THROUGH THE PERIOD...AND GENERALLY OUT OF THE ESE. OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU/HATZOS SHORT TERM...BINAU LONG TERM...CONIGLIO AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
734 PM EDT FRI MAY 18 2012 .SYNOPSIS... A WARM AND TRANQUIL WEEKEND IS IN STORE FOR THE AREA AS A DEEP LAYERED RIDGE OF HIGH PRESSURE MOVES ACROSS OHIO INTO INTERIOR NEW ENGLAND BY LATER ON SUNDAY. WEAK EASTERLY FLOW AT THE SURFACE WILL HOLD DEEPER MOISTURE AT BAY...BUT HUMIDITIES WILL BE ON THE INCREASE OVER WHAT HAS BEEN EXPERIENCED THE PREVIOUS FEW DAYS. A WEAKENING WEATHER SYSTEM SHIFTING THROUGH THE WESTERN GREAT LAKES SUNDAY NIGHT WILL SLOW AS IT MOVES INTO THE OHIO VALLEY...BRINGING THE NEXT THREAT OF SHOWERS AND THUNDERSTORMS. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AMPLE SUNSHINE AGAIN TODAY WITH LOW DEWPOINTS /30S AND 40S/...THANKS TO DEEP LAYERED RIDGE OF HIGH PRESSURE OVER THE AREA. 18.19Z RUC ANALYSIS INDICATED A CLOSED-CONTOUR 580DM ANTICYCLONE OVER NRN INDIANA...ATOP A CLOSED-CONTOUR 576DM CYCLONE JUST OFF THE SOUTH CAROLINA COAST. NOT OVER STRONG/IMPRESSIVE SYSTEMS...BUT THIS REX BLOCK TYPE STRUCTURE WILL CONTINUE TO DOMINATE OUR WEEKEND WEATHER PATTERN...WITH WEAK EASTERLY FLOW OUT OF A SURFACE HIGH PRESSURE SYSTEM IN NEW ENGLAND /RATHER BAGGY PRESSURE GRADIENT/ CONTINUING TO HOLD DEEPER BOUNDARY LAYER MOISTURE /60S DEWPOINTS/ WELL SOUTH AND WEST OF THE AREA. IN THE UPCOMING 12-15 HOURS...EXPECT VERY LITTLE SYNOPTIC SCALE CHANGE AS THE MID-LEVEL HIGH DRIFTS THROUGH NRN OHIO AND STRENGTHENS SLIGHTLY WHILE THE LOW OVER THE WRN ATL ELONGATES SOME BEGINS SPLITTING INTO TWO DISTINCT CYCLONIC CIRCULATION CENTERS...ONE IN ERN GA AND THE OTHER OFF THE NC COAST. VERY WEAK SFC FLOW WILL QUICKLY GO CALM THIS EVENING UNDER RAPIDLY STRENGTHENING INVERSION AND DECOUPLING OF THE SHALLOWING BOUNDARY LAYER. THIS SHOULD FOSTER A RAPID EVENING TEMP DROP WITH CLEAR SKIES. RAN A GENERAL BLEND OF THE PREVIOUS FORECAST AND 12Z ECMWF/GFS/NAM MOS...THOUGH TWEAKED A TOUCH DOWNWARD IN THE COOL SPOTS GIVEN IDEAL RADIATIONAL COOLING REGIME. ALSO FOGGED UP THE OHIO AND ADJACENT RIVER VALLEYS LATER IN THE NIGHT...AS BOUNDARY LAYER MOISTURE FROM KY WILL BE SEEPING NWRD OVERNIGHT AS MINOR SLY COMPONENT TO THE GENERAL EASTERLY FLOW WILL ALLOW AN INCREASE IN LLVL MOISTURE. WOULD NOT BE SURPRISED IS FOG BECOMES A LITTLE MORE WIDESPREAD THAN FORECAST ESP OVER NRN KY/SRN OH/SERN IND. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... VERY LITTLE CHANGE TO THE PATTERN ALOFT ON SATURDAY...THOUGH THE LOW LEVELS WILL BEGIN TO UNDERGO SOME MOISTURE ADVECTION...ESPECIALLY ACROSS SRN/SWRN FORECAST AREA. 18.12Z WRF/GFS INDICATE LOWEST 1KM SPECIFIC HUMIDITIES DOUBLING IN COMPARISON TO FRIDAY...SO BROUGHT DEWPOINTS UP A BIT IN THE SOUTH/SOUTHWEST...PERHAPS NOT ENOUGH. FEEL 18.12Z NAM-WRF SFC DWPTS ABOUT 10F TOO HIGH AS HAS BEEN A PROBLEM THIS SPRING...SO DISCOUNTING THE RATHER STRONG INSTBY THAT DEVELOPS UNDERNEATH THE MID LEVEL RIDGE SATURDAY AFTERNOON. EVEN SO...ADDITIONAL MOISTURE AND A FAVORABLE LAPSE RATE WILL NO DOUBT YIELD SOME DEEPER CUMULUS ACROSS THE SOUTH/SOUTHWEST...BUT THINK NIL FORCING AND CONTINUED RISING HEIGHTS WILL MITIGATE A NEED FOR A RAIN CHANCE AT THIS TIME. A WARM DAY...AND MOS SHOULD PERFORM WELL IN THIS RATHER PREDICTABLE REGIME...SO AGAIN BLENDED PREVIOUS FORECAST WITH MOST RECENT VALUES. SPOT CHECK OF LOW LEVEL THICKNESS CONSIDERATIONS AND MIXING TO 850-825MB /DESPITE VERY WEAK FLOW/ SUGGESTS WIDESPREAD LOWER TO MIDDLE 80S...VERY MUCH IN LINE WITH THE BLEND. LIKELY A REPEAT SCENARIO SATURDAY NIGHT WITH VALLEY FOG...AND LOWS IN THE 50S. SUNDAY IS A CARBON-COPY OF SATURDAY. DISTINCT CIRCULATION CENTERS ATTENDANT TO THE SOUTHEAST CONUS TROUGH RECOMBINE OVER THE OUTER BANKS OF NC WHILE THE MID LEVEL ANTICYCLONE CONTINUES TO DEEPEN TO 585DM OVER INTERIOR NEW ENGLAND. THIS WILL REINFORCE A LOW LEVEL EASTERLY TRAJECTORY...THUS DON/T EXPECT MUCH /IF ANY/ DEWPOINT RISE ON SUNDAY...AND TEMPERATURES SHOULD HOLD VERY SIMILAR TO SATURDAY/S READINGS. PROBABLY A THICKER CIRRUS SHIELD PER BUFR SOUNDINGS...BUT THAT WOULD BE ABOUT THE EXTENT OF SENSIBLE WEATHER. SUNDAY NIGHT BEGINS TO SEE SOME CHANGE AS A TROUGH OF LOW PRESSURE /DAMPENING OUT AND SLOWING AS IT ENCOUNTERS THE BLOCKY FLOW ALONG THE EAST COAST/ APPROACHES THE GREAT LAKES. HAVE KEPT THE NIGHTTIME DRY AT THIS POINT AS 18.12Z GUIDANCE WAFFLING ON WEAK/MID LEVEL- BASED SHOWERS AND STORM PLACEMENT AS FORCING SLOWLY INCREASES LATER IN THE NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... PERIOD OF DRY WEATHER MAY COME TO AN END MONDAY AS MOISTURE AND INSTABILITY INCREASE AHEAD OF AN UPPER TROUGH. WITH THE ECMWF AND GFS COMING INTO FAIR AGREEMENT...KEPT A CHANCE OF THUNDERSTORMS FOR MONDAY...MAINLY IN WESTERN COUNTIES THAT WILL BE AFFECTED MORE BY SURFACE CONVERGENCE AND COOLER AIR ALOFT. STAYED CLOSE TO ECMWF SOLUTION FOR TUESDAY SINCE IT CONTINUES TO SHOW A CLOSED UPPER LOW FORMING AS OPPOSED TO THE FASTER OPEN WAVE DEPICTED ON THE GFS. AS THE UPPER LOW FORMS NEAR CVG...THERE WILL BE A GOOD CHANCE FOR THUNDERSTORMS UNDER A COOL POOL ALOFT COUPLED WITH DEEP MOISTURE ADVECTION FROM THE SOUTH. THUNDERSTORMS CHANCES WILL DIMINISH ON WEDNESDAY AS THE CLOSED UPPER LOW SLIPS EAST ALLOWING DRIER AND MORE STABLE AIR TO WORK IN. THE DRY CONDITIONS ARE EXPECTED TO CONTINUE ON THURSDAY AND FRIDAY WHEN RIDGING ALOFT IS FORECAST TO MOVE BACK IN. HIGH TEMPERATURES WILL BE MAINLY IN THE 80S MONDAY ON THE EAST SIDE OF THE UPPER TROUGH. COOLER READINGS IN THE 70S ARE FORECAST AS THE CLOSED LOW MAKES ITS WAY ACROSS THE AREA WITH ASSOCIATED CLOUD COVER AND COLD ADVECTION. LOOK FOR A REBOUND TO THE 80S BY FRIDAY AS SUNSHINE AND WARM ADVECTION RETURN. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE WILL MAINTAIN CONTROL OF THE WEATHER THROUGH THE TAF PERIOD. LOW LEVEL MOISTURE WILL BE INCREASING OVER THE NEXT DAY OR SO...WHICH WILL ALLOW FOR SOME CUMULUS DEVELOPMENT TOMORROW. OVERNIGHT TONIGHT...IT MAY ALLOW FOR SOME FOG TO DEVELOP AT THE CINCINNATI TAF SITES (INCLUDING LIFR AT KLUK). WINDS WILL REMAIN FAIRLY LIGHT THROUGH THE PERIOD...AND GENERALLY OUT OF THE ESE. OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU SHORT TERM...BINAU LONG TERM...CONIGLIO AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
122 AM EDT THU MAY 17 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION PROVIDING DRY WEATHER THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES WILL GRADUALLY WARM TO ABOVE NORMAL BY FRIDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE SURFACE COLD FRONT HAS JUST ABOUT CLEARED THE CWA...WITH ALL SHOWER ACTIVITY NOW SOUTH OF THE BORDERING COUNTIES. ALTHOUGH WINDS ARE OUT OF THE NORTHEAST AT ALL LOCATIONS...THE DEWPOINT GRADIENT IS STILL LOCATED NEAR THE OHIO RIVER...WITH DEWPOINTS IN THE MID 50S SOUTH OF THERE (AND MUCH DRIER CONDITIONS TO THE NORTH). ONLY MINOR ADJUSTMENTS WERE NECESSARY TO THE FORECAST...PRIMARILY TO END POPS AND CLEAN UP THE SKY GRIDS TO REFLECT CURRENT CONDITIONS. LOW TEMPERATURES APPEAR TO BE ON TRACK...AND SOME READINGS BELOW 40 ARE POSSIBLE IN CENTRAL OHIO. PREVIOUS DISCUSSION > UPPER LEVEL TROF TO PIVOT EAST THRU THE GREAT LAKES INTO NEW ENGLAND/SE CANADA BY THURSDAY MORNING. ASSOCIATED COLD FRONT WHICH EXTENDS FROM WESTERN PA THRU SW OHIO AND SRN INDIANA TO DROP SOUTH OF THE OHIO RIVER BY LATE AFTERNOON. BOTH NAM/GFS APPEAR OVERDONE WITH SURFACE DEWPOINTS POOLED IN THE MID 60S ALONG AND SOUTH OF THE FRONTAL BOUNDARY. 13 KM RAP MODEL SOLN LOOKS MORE REALISTIC WITH DEWPOINTS IN THE UPPER 50S YIELDING MARGINAL BLYR CAPES LESS THAN 1000 J/KG ACRS SE OHIO AND NRN KY. WL CONTINUE TO LIMIT POPS TO SLIGHT CHANCE FOR THUNDERSTORMS ACRS THESE AREAS EARLY. SINCE CONVECTION IS STARTING TO DEVELOP WILL OPT FOR AREAL COVERAGE WORDING...ISOLATED THUNDERSTORMS. IN THE WAKE OF THIS FRONT SFC HIGH PRESSURE BUILDS INTO THE GREAT LAKES OVERNIGHT. SUBSIDENCE WILL LEAD TO CLEARING SKIES. DRY AIRMASS AND LOW LEVEL CAA WILL LEAD TO BELOW NORMAL TEMPERATURES. HAVE FCST LOWS RANGING FROM NEAR 40 NE TO LOWER 50S FAR SOUTH. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... SURFACE HIGH PRESSURE TO BUILD ACROSS THE GREAT LAKES ON THURSDAY. DRY AIRMASS WILL RESULT IN MOSTLY SUNNY SKY CONDITIONS. EXPECT TEMPS TO BE SLIGHTLY BELOW NORMAL. AFTER A COOL START TO THE DAY EXPECT HIGHS TO RANGE FROM NEAR 70 NE TO THE MID 70S SW. SURFACE HIGH PRESSURE TO SLIDE OFF TO THE EAST THURSDAY NIGHT. EXPECT MAINLY CLEAR SKIES WITH ONLY SOME THIN HIGH LEVEL CLOUDS SPILLING IN. HAVE FCST TEMPS RANGING FROM MID 40S NORTHEAST TO THE LOWER 50S SOUTH. MID/UPR LEVEL RIDGE TO BUILD INTO OHIO ON FRIDAY. EXPECT TO SEE A GOOD DEAL OF SUNSHINE WITH JUST SOME HIGH LEVEL CLOUDINESS. UNDER THE INFLUENCE OF WAA TEMPS WILL WARM TO VALUES ABOVE NORMAL. HAVE FCST HIGHS FROM NEAR 80 NORTH TO THE LOWER 80S SOUTH. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... WITH AN UPPER RIDGE BUILDING OVERHEAD AND SURFACE HIGH PRESSURE CENTERED TO THE EAST...A PERIOD OF DRY WEATHER IS INDICATED FOR SATURDAY THROUGH MONDAY. CONFIDENCE IS RATHER HIGH FOR THIS TIME FRAME DUE TO MODEL CONSISTENCY FROM RUN TO RUN. AN UPPER LOW IS SHOWN TO DEVELOP OVER THE MISSISSIPPI VALLEY ON TUESDAY...ACCOMPANIED BY INCREASING MOISTURE. THE LOW IS FORECAST TO MOVE TO INDIANA ON WEDNESDAY. MODELS HAVE BEEN INCONSISTENT WITH THE PATH OF THE UPPER LOW...MAKING THIS PART OF THE FORECAST LESS CERTAIN. WENT WITH A CHANCE OF THUNDERSTORMS IN WESTERN COUNTIES ON TUESDAY...EXPANDING TO THE WHOLE AREA ON WEDNESDAY. WITH THE AREA IN A SOUTHERLY FLOW AND WITH CONSIDERABLE SUNSHINE TO START...TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE PERIOD. HIGHS WILL BE MAINLY IN THE 80S SATURDAY THROUGH MONDAY...WITH INCREASING CLOUDS AND POSSIBLE PRECIPITATION CAUSING READINGS TO SLIP TO THE MID AND UPPER 70S BY WEDNESDAY. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE AND AN ASSOCIATED DRY AIRMASS WILL REMAIN IN PLACE ACROSS THE REGION THROUGH TONIGHT. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...AR NEAR TERM...HATZOS/AR SHORT TERM...AR LONG TERM...CONIGLIO AVIATION...JGL
AREA FORECAST DISCUSSION
NWS PORTLAND OR
928 PM PDT WED MAY 16 2012 .SYNOPSIS...ONSHORE FLOW WILL CONTINUE AS A WEAK UPPER LEVEL TROUGH APPROACHES TONIGHT AND CROSSES THURSDAY. LOW CLOUDS WILL SPREAD INLAND BY THURSDAY EVENING WITH PATCHY DRIZZLE POSSIBLE AS THE UPPER TROUGH MOVES EAST THURSDAY NIGHT AND FRIDAY. MOST AREAS WILL REMAIN DRY THROUGH THE WEEKEND. A RETURN TO WET WEATHER IS LIKELY NEXT WEEK. && .SHORT TERM...TONIGHT THROUGH SATURDAY...MINIMAL CLOUD COVER THIS EVENING WITH HIGH CLOUDS REMAINING DOMINANT..ALBEIT THIN. SURFACE DEWPOINTS CONTINUE TO DROP AS WELL BOTH INLAND AND TO A LESSER AMOUNT AT THE COAST. AS SUCH...FEEL PREVIOUS THOUGHTS OF LOW CLOUDS PROGRESSING INLAND MAY NOT MATERIALIZE. UPDATE WILL BE AVAILABLE SHORTLY TO REDUCE CLOUD COVER FROM THE OVERNIGHT PERIOD AND EARLY TOMORROW MORNING. AS AN UPPER TROUGH SLIDES ACROSS THE REGION TOMORROW...EXPECT MARINE MOISTURE WILL STAND A BETTER CHANCE OF STRENGTHENING AND PUSHING INLAND SO WILL LEAVE THE HIGHER CLOUD COVER IN PLACE FOR TOMORROW AFTERNOON AND THEREAFTER. BY REMOVING CLOUDS...HAVE ALSO DROPPED TEMPERATURES TONIGHT CLOSER TO WHAT WAS SEEN LAST NIGHT OR EVEN A LITTLE COOLER. EXTENSIVE LOW CLOUDS LOOK TO CONTINUE FRI MORNING AS ONSHORE FLOW CONTINUES AND THE MARINE LAYER REMAINS DEEP...WITH SOME DRIZZLE OR ISOLATED SHOWERS POSSIBLE OVER THE HIGHER TERRAIN. THE CLOUD COVER AND COOLER AIR MASS WILL KEEP TEMPERATURES BELOW NORMAL LEVELS THURSDAY AND FRIDAY. HIGH PRESSURE WILL AGAIN BUILD INTO THE PACIFIC NORTHWEST SATURDAY FOR A RETURN TO DRY SUNNY WEATHER WITH TEMPERATURES WARMING UP TO NEAR 70 DEGREES. /JBONK .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...THE EXTENDED FORECAST PERIOD BEGINS SATURDAY EVENING AS UPPER LEVEL RIDGING OVER THE PACIFIC NORTHWEST IS ABOUT TO BREAK DOWN AND OPEN THE DOOR FOR COOLER AND WETTER WEATHER AFTER SUNDAY. AN UPPER TROUGH APPROACHES THE AREA...BRINGING A FRONT ONSHORE MONDAY. AS THE FRONT MOVES THROUGH...THE JET STREAM DIPS SOUTH AND STRENGTHENS OVER THE EASTERN PACIFIC. THIS DIRECTS A STORM TRACK AT THE NORTHWEST COAST THROUGH ABOUT MIDWEEK. MODELS BEGIN TO DISAGREE AFTER MIDWEEK THOUGH AS THE GFS AND THE GEM BUILD A RELATIVELY HIGH AMPLITUDE RIDGE OFFSHORE WITH A TROUGH OVER THE WEST COAST. THE ECMWF LEANS TOWARD A MORE ZONAL FLOW WITH POTENTIALLY WETTER WEATHER ON THE WAY. EITHER WAY...IT APPEARS THAT THE SHORT BOUT OF SUNNY WEATHER MAY BE TEMPORARILY ENDING. KELSON && .AVIATION...MVFR STRATUS IS LINGERING NEAR THE COLUMBIA RIVER MOUTH...WITH SOME PATCHY FOG FURTHER SOUTH ALONG THE IMMEDIATE COASTLINE NEAR KONP. EXPECT IFR/MVFR STRATUS TO REDEVELOP ALONG THE COAST OVERNIGHT BEFORE POSSIBLY SPREADING INLAND LATE TONIGHT...PARTICULARLY ALONG THE COLUMBIA RIVER. AT THIS TIME...MODELS INCLUDING THE RAP AND NAM CONTINUE TO SUGGEST STRATUS SPREADING DOWN THE COLUMBIA RIVER. THE HI RESOLUTION RAPID REFRESH MODELS DOES INDICATE SOME INLAND PENETRATION DOWN THE RIVER...BUT NOT TO THE INLAND TAF SITES AND NOT THROUGH THE COASTAL GAPS. THEREFORE CONFIDENCE AT THIS TIME IS LOW IN SEEING INLAND STRATUS...AND WILL ELIMINATE THE BROKEN CEILING AND JUST LEAVE A SCATTERED MENTION FOR NOW. THAT SAID...WE DO HAVE AN UPPER TROUGH MOVING IN WHICH MAY ACT TO STRENGTHEN THE MARINE LAYER. IF IT DOES DEVELOP ACROSS THE INTERIOR...IT SHOULD BURN OFF FAIRLY QUICKLY THURSDAY. EXPECT A DIURNAL INCREASE IN NW WINDS LATE AFTERNOON AND EARLY EVENING. KMD && .MARINE...HIGH PRESSURE CENTERED NEAR 50 N/140W WILL WEAKEN SLOWLY THE NEXT FEW DAYS AND MIGRATE CLOSER TO SHORE. MARGINAL SMALL CRAFT ADVISORY LEVEL WINDS WILL CONTINUE MAINLY OVER THE OUTER WATERS WITH ONSHORE NNW FLOW. WINDS PEAK IN THE AFTERNOON THURSDAY...BEFORE EASING FRIDAY AS HIGH PRESSURE BECOMES CENTERED OVER THE COASTAL WATERS. THIS WILL OPEN THE DOOR FOR A WEATHER PATTERN CHANGE...AND ALLOW A FEW PACIFIC FRONTAL SYSTEMS TO MOVE INTO THE WATERS NEXT WEEK. THE PROLONGED NW WINDS STILL APPEAR LIKELY TO DRIVE SEAS UP TO NEAR 10 TO 11 FT BY THURSDAY ACROSS THE NORTHERN OUTER WATERS...BEFORE SUBSIDING THURSDAY NIGHT. KMD && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THURSDAY FOR WATERS FROM CAPE SHOALWATER WA TOFLORENCE OR FROM 10 TO 60 NM. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM TO 5 PM PDT THURSDAY FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM. && $$ MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
229 PM EDT THU MAY 17 2012 .SYNOPSIS... AN UPPER LEVEL LOW WILL FORM OVER SOUTH CAROLINA...AND WILL MOVE TO THE NORTH CAROLINA COAST...WHERE IT WILL LINGER INTO EARLY NEXT WEEK. HIGH PRESSURE WILL BUILD IN FROM THE NORTH AND REMAIN THROUGH MONDAY. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON TUESDAY. && .NEAR TERM /THROUGH FRIDAY/... WATER VAPOR IMAGERY AND THE LATEST RAP MODEL RUN SHOW A NE TO SW ORIENTED UPPER LOW STRETCHED OVER THE MIDLANDS OF SOUTH CAROLINA...BACK ACROSS SOUTHEAST GEORGIA. A SPOKE OF PVA ON THE WEST SIDE OF THE LOW IS HELPING TO ORGANIZE STRONG TO SEVERE CONVECTION ACROSS THE SOUTHERN PART OF THE UPSTATE. ELSEWHERE...OTHER STORMS WERE DEVELOPING OVER THE BLUE RIDGE OF NE GA AND SW NC. SOMEWHAT DRIER AIR HAS PUSHED INTO THE NRN PIEDMONT AND FOOTHILLS OF NE...BUT AREAS TO THE SOUTH REMAIN QUITE UNSTABLE WITH SB-CAPE VALUES RUNNING FROM 1500-2000 J/JG. OUR LOCAL WORKSTATION WRF...THE NCEP 4KM WRF AND THE HRRR ALL AGREE IN DEVELOPING CONVECTION OVER MUCH OF THE UPSTATE...SOUTHERN NC MTNS AND FOOTHILLS AND NE GA INTO THE EVENING HOURS. THIS WOULD BE SIMILAR TO WHAT HAPPENED LAST NIGHT. CONFIDENCE IN THIS DEVELOPMENT IS FAIRLY HIGH...AND POPS WILL BE PUSHED UP TO 50 PERCENT ACROSS THE I-85 CORRIDOR AND UP INTO THE WRN NC FOOTHILLS FOR THE EVENING HOURS. COOL MID-LEVEL TEMPS AND DRY AIR ALOFT WILL CONTINUE TO SUPPORT SEVERE WIND AND HAIL EVENTS. A BACK DOOR COLD FRONT WILL CROSS THE REGION LATE TONIGHT. THE NAM MIXES DEWPOINTS INTO THE U40S TO L50S ACROSS THE NC FOOTHILLS AND PIEDMONT AND THE ERN UPSTATE. THIS SHOULD FINALLY END THE THREAT OF STORMS FOR THESE AREAS. BACK ACROSS THE MOUNTAINS...ESPECIALLY CLOSER TO THE TN LINE...SCT CONVECTION SHOULD DEVELOP AGAIN TMRW WHERE LLVL MOISTURE CONVERGENCE WILL BE MAXIMIZED. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AT 1430 EDT THURSDAY...A CLOSED UPPER LOW...PART OF AN EAST COAST REX ...WILL BE LOCATED NEAR THE NC COAST ON FRIDAY NIGHT AND SATURDAY. ON SUNDAY THIS FEATURE RETROGRADES SLIGHTLY INLAND. THE MODELS SHOW DRIER AIR MOVING SW INTO OUR AREA ON THE BACK SIDE OF THE LOW FRIDAY NIGHT AND SATURDAY....WHILE SOME MOISTURE LINGERS ALONG THE BLUE RIDGE. ON SATURDAY NIGHT THE NAM SHOWS MOISTURE SPREADING WEST ACROSS THE INTERSTATE 77 CORRIDOR TO THE NC BLUE RIDGE...WHILE THE GFS REMAINS RATHER DRY UNTIL SUNDAY NIGHT. POPS WILL INITIALLY BE QUITE LOW AND FOCUSED ALONG THE BLUE RIDGE...THEN WILL INCREASE SLIGHTLY FROM THE EAST TOWARD SUNDAY... BUT REMAINING RATHER LOW AS CONFIDENCE IS LIMITED ON THE AMOUNT AND TIMING OF MOISTURE ENCROACHMENT FROM THE EAST. TEMPERATURES WILL GENERALLY BE SLIGHTLY BELLOW NORMAL UNDER THE UPPER LOW HEIGHT ANOMALY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AT 1430 EDT THURSDAY...A LONGWAVE TROUGH WILL PROGRESS ACROSS THE EASTERN USA FROM MONDAY THROUGH WEDNESDAY...PROGRESSING OFFSHORE ON THURSDAY WHEN A LONGWAVE RIDGE AXIS CROSSES THE MS RIVER VALLEY. A CLOSED UPPER LOW WILL REMAIN NEAR THE CAROLINA COAST ON MONDAY. THIS LOW FILLS AND DRIFTS NORTHEAST ON TUESDAY. A SHORTWAVE TROUGH DROPS SOUTHEAST OVER THE SOUTHERN APPALACHIANS LATE TUESDAY...MOVING OFF TO THE EAST ON WEDNESDAY. SURFACE HIGH PRESSURE WILL BE OVER OUR ARE ON MONDAY...BETWEEN A COASTAL LOW AND A COLD FRONT IN THE MS RIVER VALLEY. CONFIDENCE IS LIMITED ON THE WESTERN EXTENT OF MOISTURE THAT WILL WRAP AROUND THE COASTAL LOW TOWARD THE SOUTHERN APPALACHIANS...AND THE RESULTANT POPS. THE COLD FRONT TO OUR WEST REACHES THE SOUTHERN APPALACHIANS ON TUESDAY WHILE WEAKENING...WITH THE REMAINS OF THE BOUNDARY SUPPORTING LENDING SUPPORT TO AT LEAST SMALL POPS. WEDNESDAY AND THURSDAY FIND OUR AREA UNDER WEAK HIGH PRESSURE...BUT THE MODELS DEPICT SOME AMOUNT OF LINGERING MOISTURE...OSTENSIBLY ASSOCIATED WITH THE REMAINS OF THE FORMER FRONT. WITH GULF INFLOW EVENTUALLY SETTING UP TO OUR WEST...SMALL POPS WILL BE MAINTAINED INTO THURSDAY...ESPECIALLY IN THE WEST. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL IN MINOR HEIGHTS RISES BEHIND THE DEPARTING UPPER LOW. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... AT KCLT...STRONG THUNDERSTORMS WILL CONTINUE TO FIRE ABOUT 15 MILES SOUTH OF THE AIRFIELD...THEN DRIFT SOUTH FROM THERE...OVER THE NEXT COUPLE HOURS. HOWEVER...THE AIRMASS WILL BECOME MORE UNSTABLE BY LATE AFTN. MOST OF THE SHORT RANGE MODELS WANT TO DEVELOP TSTMS AROUND THE AIRFIELD STARTING IN A COUPLE HOURS AND THE NNE TO SSW ORIENTED BANDS OF CU ACROSS THE REGION WILL LIKELY START TO DEEPEN INTO CB/S WITH TIME. I/VE HELD ON TO VCSH TO ACCOUNT FOR THIS...BUT A PERIOD OF TEMPO TSRA WILL PROBABLY NEED TO BE ADDED ONCE DEVELOPMENT STARTS TO OCCUR FARTHER NORTH. WINDS WILL REMAIN OUT OF THE NE THIS AFTN...THOUGH OUTFLOW BNDRYS MAY PLAY HAVOC WITH THE WINDS AT TIMES. MVFR CIGS ARE EXPECTED AFTER MIDNIGHT AS A BACK DOOR COLD FRONT SURGES THROUGH THE REGION. THE CIGS ARE EXPECTED TO CLEAR OUT BEFORE SUNRISE HOWEVER. ELSEWHERE...MUCH LIKE AT KCLT...THE ATMOSPHERE WILL BECOME MORE UNSTABLE OVER THE UPSTATE...AND TSTMS WILL LIKELY BEGIN TO DEVELOP ON OUTFLOW BNDRYS FROM STORMS EAST OF THE REGION NOW. THIS PROCESS WILL TAKE A COUPLE HOURS. VCHS IS IN THE TAFS NOW...BUT A PERIOD OF TEMPO GROUPS IS A GOOD BET ONCE THE NEW CELLS BEGIN TO FIRE. CONFIDENCE IN TIMING JUST ISN/T HIGH ENUF TO TEMPO YET. KAVL IS MORE STABLE...BUT SHRA MAY CONTINUE THERE FOR A GOOD BIT OF THE NIGHT. WINDS OVER THE UPSTATE WILL GENERALLY BE OUT OF THE EAST THE REST OF THE AFTN...TURNING NE LATE TONIGHT AS A BACK DOOR FRONT SURGES THROUGH. A PERIOD OF MVFR CIGS IS EXPECTED TO ACCOMPANY THE FRONT. OUTLOOK...EXPECT ISOLD LATE DAY SHOWERS AND TSTMS IN THE MTNS FRI AFTN....THEN DRYING OVER THE WEEKEND. MRNG FOG WILL BE PSBL...ESP MTN VALLEYS AND NEAR LAKES/RIVERS. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JAT NEAR TERM...MCAVOY SHORT TERM...JAT LONG TERM...JAT AVIATION...MCAVOY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
257 PM MDT THU MAY 17 2012 .DISCUSSION... A BROAD...FLAT LONG WAVE TROF EXTENDS FROM COAST TO COAST THIS MORNING WITH A SHORT WAVE TROF OVER CO. MODELS ARE IN GOOD AGREEMENT IN BRINING A STRONGER TROF INLAND FROM THE PAC TO A POSITION JUST W OF OUR CWA BY 12Z SAT. AIR MASS OVER THE AREA IS CHARACTERIZED BY VERY STEEP LOW LEVEL LAPSE RATES AND LIMITED MOISTURE. A FEW TSTMS HAVE DVLPD THIS AFTN MAINLY OVER THE HIER TERRAIN OF THE BLACK HILLS WITH A FEW SHOWERS OVER NE WY AND NW SD. GIVEN THE DRY LOW LVLS AND STEEP BELOW CLOUD LAPSE RATES THESE STORMS COULD PRODUCE STRONG...GUSTY SFC WINDS DURING THE EVNG HOURS. THE HRRR MODEL SHOWS A N TO S LINE OF TSTMS FROM NW SD THROUGH RAP AND S WARD AT 03Z. WITH THE APPROACH OF THE SECOND TROF FRIDAY AFTN THERE IS THE CHANCE FOR MORE WIDESPREAD AND VIGOROUS CONVECTION. MOISTURE WILL REAMIN LIMITED...BUT SFC BASED CAPE FCSTS OF ABT 1000 J/KG BY THE 18Z NAM LOOK REASONABLE. SFC TO 6KM SHEAR IS FCST TO RANGE FROM ABOUT 40KTS OVER NW SD TO 20 KTS SE PORTIONS OF OUR CWA. A BOUNDARY FROM TONIGHTS CONVECTION MAY PROVIDE SOME FOCUS AND WILL BE REINFORCED BY INCREASING NRLY FLOW OVER WRN AND NWRN PORTIONS OF THE CWA. NAM FCSTS THIS BOUNDARY TO BE FROM S OF RAP TO ROUGHLY PHP AT 21Z FRIDAY. WITH THE APPROACHING TROF...500 MB Q VECTOR CONVERGENCE REMAINS OVER THE AREA FRIDAY NIGHT INTO SATURDAY EVG. POST FRONTAL SHOWERS AND TSTMS SHOULD CONTINUE OVER MUCH THE AREA...GRADUALLY ENDING FROM THE NW. EXTENDED...AN UPPER RIDGE WILL BUILD INTO THE REGION EARLY NEXT WEEK BRINGING DRY CONDITIONS. TEMPERATURES WILL BE NEAR AVERAGE SUNDAY...WITH A GRADUAL WARMING TREND TO START THE WORK WEEK. MODELS CONTINUE TO SHOW A SLOW MOVING UPPER TROUGH PUSHING INTO THE REGION LATE TUESDAY INTO WEDNESDAY AND THURSDAY. MODELS CONSISTENCY IS STILL LACKING (ECMWF CLOSES THE SYSTEM OFF WHILE GEM/GFS KEEP IT OPEN)...BUT THIS COULD BRING A ROUND OF SHOWERS SHOWERS AND THUNDERSTORMS TO THE AREA. && .AVIATION...18Z TAFS ISOLD/SCT TSRA AND SHRA WILL BE POSSIBLE THIS AFT AND EVE. VARIABLE AND GUSTY WINDS ARE EXPECTED IN THE VICINITY OF ANY SHRA OR TSRA. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...BARBER LONG TERM....77 AVIATION...77
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1218 PM CDT THU MAY 17 2012 .DISCUSSION.../ISSUED AT 1007 AM CDT/ NOT MUCH CHANGE TO CURRENT FORECAST. ACCAS SHOWERS NORTH OF WARM FRONT HAS EXITED CWA WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED THIS AFTERNOON. WINDS WILL BE GUSTY THIS AFTERNOON AND WILL BE CLOSE TO WIND ADVISORY CRITERIA BUT WILL NOT ISSUE SINCE EVERYONE PRETTY MUCH KNOWS IT IS WINDY. CURRENT TEMPERATURE FORECAST ON TRACK. && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ VFR CONDITIONS EXPECTED TO REMAIN THROUGH 18Z FRIDAY. A STRONG LOW LEVEL SOUTHERLY JET WILL PRODUCE LOW LEVEL WIND SHEAR AFTER 03Z TONIGHT THROUGH 16Z FRIDAY. OTHERWISE...SURFACE WIND GUSTS TO 35 KNOTS CAN BE EXPECTED THROUGH 00Z TONIGHT AND DECREASE TO 15 TO 20 KNOTS 03Z TO 16Z FRIDAY AND THEN INCREASE TO 20 TO 35 KNOTS AGAIN DURING THE DAY ON FRIDAY. && .PREVIOUS DISCUSSION.../ISSUED AT 355 AM CDT/ WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED FROM JUST WEST OF SIOUX FALLS NORTHWARD ALONG THE INTERSTATE 29 CORRIDOR OVERNIGHT UNDER THE INFLUENCE OF WARM AIR/THETA E ADVECTION FACILITATED BY THE LOW LEVEL JET. ELEVATED CONVECTION ALIGNS FAIRLY WELL WITH THE RUC 850-500MB OMEGA AND INSTABILITY FIELDS...ALBEIT BOTH ARE RELATIVELY WEAK. THEREFORE EXPECT THE ACTIVITY TO REMAIN ISOLATED IN NATURE. CONSIDERING WINDS ARE HAULING AT 50-60 KTS AT TWO THOUSAND FEET...WILL NEED TO KEEP A CLOSE EYE ON CELLS THAT DEVELOP AS THEY COULD BE WIND PRODUCERS. BY DAYBREAK...ISOLATED ACTIVITY SHOULD BE MOSTLY CONFINED TO SW MN...AND GRADUALLY WANE WITH LOSS OF THE LLJ INFLUENCE. AFTER THE NOCTURNAL CONVECTION...THE NEXT ITEM OF FOCUS IS THE WIND TODAY AND FRIDAY. 08Z SURFACE ANALYSIS ILLUSTRATED THE LOW PRESSURE CENTER OVER WESTERN ND/SD. RELATIVELY TIGHT PRESSURE GRADIENT AHEAD OF THIS FEATURE WILL SUPPORT WIND SPEEDS NEARING ADVISORY CRITERIA /SUSTAINED 30 MPH/. NAM BUFKIT WINDS AT THE TOP OF THE MIXED LAYER ARE CIRCA 40 KTS...BUT THERE WILL BE INCREASING HIGH CLOUDS. WHILE ISOLATED LOCATIONS /ESPECIALLY HIGHER TERRAIN AREAS/ COULD BRIEFLY HIT CRITERIA...DO NOT CURRENTLY EXPECTED WIDESPREAD SUSTAINED SPEEDS AT 30 MPH. THEREFORE...WILL HOLD OFF ON AN ADVISORY FOR NOW. TEMPERATURES WILL SOAR NEARLY 15 DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS IN THE MID/UPPER 80S STILL APPEARING LIKELY. LOWS TONIGHT WILL NOT DROP MUCH DUE TO THE PERSISTENT SOUTHERLY FLOW AHEAD OF THE TROUGH. LOW TO MID 60S ARE EXPECTED TO BE COMMON AT DAYBREAK FRIDAY. H85 TEMPERATURES CLIMB TO AROUND +22C ON FRIDAY...WHICH SHOULD MAKE UPPER 80S AND LOWER 90S EASILY ATTAINABLE. THE COLD FRONT SHOULD REACH CENTRAL SD BY DAYBREAK SATURDAY...AND TRACK EASTWARD ACROSS THE FORECAST AREA THROUGHOUT THE DAY. LIKELY POPS SEEM WARRANTED ON SATURDAY AND SATURDAY NIGHT. INSTABILITY AND SHEAR PARAMETERS ARE RATHER MARGINAL ON SATURDAY...SO SEVERE THREAT STILL APPEARS TO BE FARTHER SOUTH. A FEW SHOWERS MAY LINGER ON SUNDAY MAINLY EAST OF INTERSTATE 29...AND THEN RIDGING WILL DEVELOP FOR THE START OF NEXT WEEK. AFTER TEMPERATURES ARE REDUCED BACK INTO HE MID 60S TO LOWER 70S RANGE ON SUNDAY IN THE WAKE OF THE FRONT...READINGS WILL GRADUALLY MODERATE TO VALUES IN THE UPPER 70S AND LOWER 80S FOR TUESDAY. SHOWER AND THUNDERSTORM CHANCES WILL RETURN FOR WEDNESDAY AND THURSDAY...AS A RELATIVELY HEALTHY TROUGH TRACKS ACROSS THE NORTH CENTRAL CONUS. HAVE INCLUDED 50-70 POPS FOR THIS SYSTEM. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MNZ071-072-080-081- 090. NE...NONE. SD...NONE. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1007 AM CDT THU MAY 17 2012 .DISCUSSION.../ISSUED AT 1007 AM CDT/ NOT MUCH CHANGE TO CURRENT FORECAST. ACCAS SHOWERS NORTH OF WARM FRONT HAS EXITED CWA WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED THIS AFTERNOON. WINDS WILL BE GUSTY THIS AFTERNOON AND WILL BE CLOSE TO WIND ADVISORY CRITERIA BUT WILL NOT ISSUE SINCE EVERYONE PRETTY MUCH KNOWS IT IS WINDY. CURRENT TEMPERATURE FORECAST ON TRACK. && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ VFR CONDITIONS EXPECTED TO REMAIN THROUGH FRIDAY MORNING. A STRONG LOW LEVEL JET WILL CONTINUE TO PRODUCE LOW LEVEL WIND SHEAR AT THE TAF SITES EAST OF THE JAMES RIVER VALLEY THROUGH 18Z. THESE STRONGER WINDS WILL BEGIN TO MIX OUT BY 15Z INCREASING THE SURFACE SPEEDS... GUSTING UP TO 35 KTS DURING THE AFTERNOON MOST LOCATIONS. SURFACE WIND GUSTS WILL DECREASE SOME OVERNIGHT THURSDAY NIGHT...THOUGH WINDS WILL REMAIN STRONG ALOFT CREATING ADDITIONAL LOW LEVEL WIND SHEAR FRIDAY MORNING. && .PREVIOUS DISCUSSION.../ISSUED AT 355 AM CDT/ WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED FROM JUST WEST OF SIOUX FALLS NORTHWARD ALONG THE INTERSTATE 29 CORRIDOR OVERNIGHT UNDER THE INFLUENCE OF WARM AIR/THETA E ADVECTION FACILITATED BY THE LOW LEVEL JET. ELEVATED CONVECTION ALIGNS FAIRLY WELL WITH THE RUC 850-500MB OMEGA AND INSTABILITY FIELDS...ALBEIT BOTH ARE RELATIVELY WEAK. THEREFORE EXPECT THE ACTIVITY TO REMAIN ISOLATED IN NATURE. CONSIDERING WINDS ARE HAULING AT 50-60 KTS AT TWO THOUSAND FEET...WILL NEED TO KEEP A CLOSE EYE ON CELLS THAT DEVELOP AS THEY COULD BE WIND PRODUCERS. BY DAYBREAK...ISOLATED ACTIVITY SHOULD BE MOSTLY CONFINED TO SW MN...AND GRADUALLY WANE WITH LOSS OF THE LLJ INFLUENCE. AFTER THE NOCTURNAL CONVECTION...THE NEXT ITEM OF FOCUS IS THE WIND TODAY AND FRIDAY. 08Z SURFACE ANALYSIS ILLUSTRATED THE LOW PRESSURE CENTER OVER WESTERN ND/SD. RELATIVELY TIGHT PRESSURE GRADIENT AHEAD OF THIS FEATURE WILL SUPPORT WIND SPEEDS NEARING ADVISORY CRITERIA /SUSTAINED 30 MPH/. NAM BUFKIT WINDS AT THE TOP OF THE MIXED LAYER ARE CIRCA 40 KTS...BUT THERE WILL BE INCREASING HIGH CLOUDS. WHILE ISOLATED LOCATIONS /ESPECIALLY HIGHER TERRAIN AREAS/ COULD BRIEFLY HIT CRITERIA...DO NOT CURRENTLY EXPECTED WIDESPREAD SUSTAINED SPEEDS AT 30 MPH. THEREFORE...WILL HOLD OFF ON AN ADVISORY FOR NOW. TEMPERATURES WILL SOAR NEARLY 15 DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS IN THE MID/UPPER 80S STILL APPEARING LIKELY. LOWS TONIGHT WILL NOT DROP MUCH DUE TO THE PERSISTENT SOUTHERLY FLOW AHEAD OF THE TROUGH. LOW TO MID 60S ARE EXPECTED TO BE COMMON AT DAYBREAK FRIDAY. H85 TEMPERATURES CLIMB TO AROUND +22C ON FRIDAY...WHICH SHOULD MAKE UPPER 80S AND LOWER 90S EASILY ATTAINABLE. THE COLD FRONT SHOULD REACH CENTRAL SD BY DAYBREAK SATURDAY...AND TRACK EASTWARD ACROSS THE FORECAST AREA THROUGHOUT THE DAY. LIKELY POPS SEEM WARRANTED ON SATURDAY AND SATURDAY NIGHT. INSTABILITY AND SHEAR PARAMETERS ARE RATHER MARGINAL ON SATURDAY...SO SEVERE THREAT STILL APPEARS TO BE FARTHER SOUTH. A FEW SHOWERS MAY LINGER ON SUNDAY MAINLY EAST OF INTERSTATE 29...AND THEN RIDGING WILL DEVELOP FOR THE START OF NEXT WEEK. AFTER TEMPERATURES ARE REDUCED BACK INTO HE MID 60S TO LOWER 70S RANGE ON SUNDAY IN THE WAKE OF THE FRONT...READINGS WILL GRADUALLY MODERATE TO VALUES IN THE UPPER 70S AND LOWER 80S FOR TUESDAY. SHOWER AND THUNDERSTORM CHANCES WILL RETURN FOR WEDNESDAY AND THURSDAY...AS A RELATIVELY HEALTHY TROUGH TRACKS ACROSS THE NORTH CENTRAL CONUS. HAVE INCLUDED 50-70 POPS FOR THIS SYSTEM. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...NONE. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
357 AM CDT THU MAY 17 2012 .DISCUSSION.../ISSUED AT 355 AM CDT/ WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED FROM JUST WEST OF SIOUX FALLS NORTHWARD ALONG THE INTERSTATE 29 CORRIDOR OVERNIGHT UNDER THE INFLUENCE OF WARM AIR/THETA E ADVECTION FACILITATED BY THE LOW LEVEL JET. ELEVATED CONVECTION ALIGNS FAIRLY WELL WITH THE RUC 850-500MB OMEGA AND INSTABILITY FIELDS...ALBEIT BOTH ARE RELATIVELY WEAK. THEREFORE EXPECT THE ACTIVITY TO REMAIN ISOLATED IN NATURE. CONSIDERING WINDS ARE HAULING AT 50-60 KTS AT TWO THOUSAND FEET...WILL NEED TO KEEP A CLOSE EYE ON CELLS THAT DEVELOP AS THEY COULD BE WIND PRODUCERS. BY DAYBREAK...ISOLATED ACTIVITY SHOULD BE MOSTLY CONFINED TO SW MN...AND GRADUALLY WANE WITH LOSS OF THE LLJ INFLUENCE. AFTER THE NOCTURNAL CONVECTION...THE NEXT ITEM OF FOCUS IS THE WIND TODAY AND FRIDAY. 08Z SURFACE ANALYSIS ILLUSTRATED THE LOW PRESSURE CENTER OVER WESTERN ND/SD. RELATIVELY TIGHT PRESSURE GRADIENT AHEAD OF THIS FEATURE WILL SUPPORT WIND SPEEDS NEARING ADVISORY CRITERIA /SUSTAINED 30 MPH/. NAM BUFKIT WINDS AT THE TOP OF THE MIXED LAYER ARE CIRCA 40 KTS...BUT THERE WILL BE INCREASING HIGH CLOUDS. WHILE ISOLATED LOCATIONS /ESPECIALLY HIGHER TERRAIN AREAS/ COULD BRIEFLY HIT CRITERIA...DO NOT CURRENTLY EXPECTED WIDESPREAD SUSTAINED SPEEDS AT 30 MPH. THEREFORE...WILL HOLD OFF ON AN ADVISORY FOR NOW. TEMPERATURES WILL SOAR NEARLY 15 DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR...WITH HIGHS IN THE MID/UPPER 80S STILL APPEARING LIKELY. LOWS TONIGHT WILL NOT DROP MUCH DUE TO THE PERSISTENT SOUTHERLY FLOW AHEAD OF THE TROUGH. LOW TO MID 60S ARE EXPECTED TO BE COMMON AT DAYBREAK FRIDAY. H85 TEMPERATURES CLIMB TO AROUND +22C ON FRIDAY...WHICH SHOULD MAKE UPPER 80S AND LOWER 90S EASILY ATTAINABLE. THE COLD FRONT SHOULD REACH CENTRAL SD BY DAYBREAK SATURDAY...AND TRACK EASTWARD ACROSS THE FORECAST AREA THROUGHOUT THE DAY. LIKELY POPS SEEM WARRANTED ON SATURDAY AND SATURDAY NIGHT. INSTABILITY AND SHEAR PARAMETERS ARE RATHER MARGINAL ON SATURDAY...SO SEVERE THREAT STILL APPEARS TO BE FARTHER SOUTH. A FEW SHOWERS MAY LINGER ON SUNDAY MAINLY EAST OF INTERSTATE 29...AND THEN RIDGING WILL DEVELOP FOR THE START OF NEXT WEEK. AFTER TEMPERATURES ARE REDUCED BACK INTO HE MID 60S TO LOWER 70S RANGE ON SUNDAY IN THE WAKE OF THE FRONT...READINGS WILL GRADUALLY MODERATE TO VALUES IN THE UPPER 70S AND LOWER 80S FOR TUESDAY. SHOWER AND THUNDERSTORM CHANCES WILL RETURN FOR WEDNESDAY AND THURSDAY...AS A RELATIVELY HEALTHY TROUGH TRACKS ACROSS THE NORTH CENTRAL CONUS. HAVE INCLUDED 50-70 POPS FOR THIS SYSTEM. && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ VFR CONDITIONS EXPECTED TO REMAIN THROUGH FRIDAY MORNING. A STRONG LOW LEVEL JET WILL CONTINUE TO PRODUCE LOW LEVEL WIND SHEAR AT THE TAF SITES EAST OF THE JAMES RIVER VALLEY THROUGH 18Z. THESE STRONGER WINDS WILL BEGIN TO MIX OUT BY 15Z INCREASING THE SURFACE SPEEDS... GUSTING UP TO 35 KTS DURING THE AFTERNOON MOST LOCATIONS. SURFACE WIND GUSTS WILL DECREASE SOME OVERNIGHT THURSDAY NIGHT...THOUGH WINDS WILL REMAIN STRONG ALOFT CREATING ADDITIONAL LOW LEVEL WIND SHEAR FRIDAY MORNING. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
940 PM CDT FRI MAY 18 2012 .UPDATE... GRIDS IN EXCELLENT SHAPE. NO UPDATE NEEDED. 25 && .AVIATION... ONLY CONCERNS ARE TRAJECTORY AND TIMING MVFR CIGS AFTER 09Z AND IF ANY IMPACTS WILL BE SEEN AT WRN METRO AIRPORTS BY 12Z SATURDAY. BOUNDARY LAYER RH PROGS ARE ALL SHOWING THAT MAIN TRAJECTORY OF STRATUS WILL OCCUR ACROSS THE TX HILL COUNTRY INTO WEST-CENTRAL TX JUST BEFORE 12Z SATURDAY. STRATUS WILL BE STRADDLING THE I-35/I-35 W CORRIDOR PER LATEST SOUNDINGS INCLUDING RUC OPS40 AND RH PROGS. SEE NO REASON TO REMOVE MVFR AT WACO AT THIS TIME...BUT DO NOT HAVE ENOUGH CONFIDENCE TO ADD INTO METRO TERMINALS AT THIS TIME AND WILL LEAVE VFR THROUGHOUT. WILL MONITOR SATELLITE AND OBS CLOSELY THROUGH THE EVENING ON STRATUS TRENDS. OTHERWISE...PREVAILING SOUTH FLOW 10-14 KTS TONIGHT WILL MIX LATER SATURDAY MORNING WHICH WILL RESULT IN SOME GUSTS BY MIDDAY AT OR ABOVE 25 KTS. 05/ && .PREV DISCUSSION... /ISSUED 326 PM CDT FRI MAY 18 2012/ LOW LEVEL WARM AIR ADVECTION WILL CONTINUE ACROSS THE REGION TONIGHT THROUGH SUNDAY AS SURFACE LOW PRESSURE MOVES EASTWARD FROM THE HIGH PLAINS. A RELATIVELY TIGHT PRESSURE GRADIENT WILL RESULT IN BREEZY CONDITIONS THIS EVENING AND AGAIN ON SATURDAY. AS THE SURFACE LOW MOVES EAST...SURFACE HIGH PRESSURE WILL BUILD SOUTHWARD AND A COLD FRONT WILL APPROACH THE RED RIVER SUNDAY MORNING. A FEW SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT...WITH THE BEST CHANCE OF STORMS NORTH OF THE RED RIVER. THE FRONT SHOULD STALL DURING THE DAYTIME HOURS DUE TO VIGOROUS MIXING ALONG THE LEADING EDGE...BUT WILL BEGIN TO MOVE SOUTH AGAIN SUNDAY NIGHT/MONDAY. THE BEST PUSH BEHIND THE FRONT WILL BE EAST OF THE REGION. THEREFORE...THE FRONT WILL MOST LIKELY STALL ACROSS THE NORTHERN PORTIONS OF NORTH TEXAS MONDAY AFTERNOON. THE ATMOSPHERE WILL BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND NORTH OF THE FRONT. SEVERE STORMS ARE UNLIKELY DUE TO A WEAK SHEAR PROFILE. THE COLD FRONT WILL LIFT QUICKLY NORTH OF THE REGION MONDAY NIGHT/TUESDAY AS THE UPPER PATTERN BECOMES MORE ZONAL AND RESULTS IN A THE DEVELOPMENT OF A LEE TROUGH. THIS PATTERN WILL KEEP NORTH TEXAS WARM AND HUMID NEXT WEEK WITH HIGHS MAINLY IN THE UPPER 80S AND LOW 90S AND LOWS GENERALLY IN THE 60S. 79 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 87 65 86 65 / 0 5 5 10 10 WACO, TX 65 87 65 87 66 / 0 5 5 5 10 PARIS, TX 62 85 64 86 66 / 0 5 5 10 10 DENTON, TX 63 87 64 85 64 / 0 5 5 10 10 MCKINNEY, TX 61 87 64 86 65 / 0 5 5 10 10 DALLAS, TX 64 87 64 88 65 / 0 5 5 10 10 TERRELL, TX 63 88 63 86 64 / 0 5 5 10 10 CORSICANA, TX 64 88 65 87 67 / 0 5 5 5 10 TEMPLE, TX 64 86 64 86 65 / 0 5 5 5 10 MINERAL WELLS, TX 63 89 65 86 63 / 0 5 5 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/25
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
639 PM CDT FRI MAY 18 2012 .AVIATION... ONLY CONCERNS ARE TRAJECTORY AND TIMING MVFR CIGS AFTER 09Z AND IF ANY IMPACTS WILL BE SEEN AT WRN METRO AIRPORTS BY 12Z SATURDAY. BOUNDARY LAYER RH PROGS ARE ALL SHOWING THAT MAIN TRAJECTORY OF STRATUS WILL OCCUR ACROSS THE TX HILL COUNTRY INTO WEST-CENTRAL TX JUST BEFORE 12Z SATURDAY. STRATUS WILL BE STRADDLING THE I-35/I-35 W CORRIDOR PER LATEST SOUNDINGS INCLUDING RUC OPS40 AND RH PROGS. SEE NO REASON TO REMOVE MVFR AT WACO AT THIS TIME...BUT DO NOT HAVE ENOUGH CONFIDENCE TO ADD INTO METRO TERMINALS AT THIS TIME AND WILL LEAVE VFR THROUGHOUT. WILL MONITOR SATELLITE AND OBS CLOSELY THROUGH THE EVENING ON STRATUS TRENDS. OTHERWISE...PREVAILING SOUTH FLOW 10-14 KTS TONIGHT WILL MIX LATER SATURDAY MORNING WHICH WILL RESULT IN SOME GUSTS BY MIDDAY AT OR ABOVE 25 KTS. 05/ && .PREV DISCUSSION... /ISSUED 326 PM CDT FRI MAY 18 2012/ LOW LEVEL WARM AIR ADVECTION WILL CONTINUE ACROSS THE REGION TONIGHT THROUGH SUNDAY AS SURFACE LOW PRESSURE MOVES EASTWARD FROM THE HIGH PLAINS. A RELATIVELY TIGHT PRESSURE GRADIENT WILL RESULT IN BREEZY CONDITIONS THIS EVENING AND AGAIN ON SATURDAY. AS THE SURFACE LOW MOVES EAST...SURFACE HIGH PRESSURE WILL BUILD SOUTHWARD AND A COLD FRONT WILL APPROACH THE RED RIVER SUNDAY MORNING. A FEW SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT...WITH THE BEST CHANCE OF STORMS NORTH OF THE RED RIVER. THE FRONT SHOULD STALL DURING THE DAYTIME HOURS DUE TO VIGOROUS MIXING ALONG THE LEADING EDGE...BUT WILL BEGIN TO MOVE SOUTH AGAIN SUNDAY NIGHT/MONDAY. THE BEST PUSH BEHIND THE FRONT WILL BE EAST OF THE REGION. THEREFORE...THE FRONT WILL MOST LIKELY STALL ACROSS THE NORTHERN PORTIONS OF NORTH TEXAS MONDAY AFTERNOON. THE ATMOSPHERE WILL BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND NORTH OF THE FRONT. SEVERE STORMS ARE UNLIKELY DUE TO A WEAK SHEAR PROFILE. THE COLD FRONT WILL LIFT QUICKLY NORTH OF THE REGION MONDAY NIGHT/TUESDAY AS THE UPPER PATTERN BECOMES MORE ZONAL AND RESULTS IN A THE DEVELOPMENT OF A LEE TROUGH. THIS PATTERN WILL KEEP NORTH TEXAS WARM AND HUMID NEXT WEEK WITH HIGHS MAINLY IN THE UPPER 80S AND LOW 90S AND LOWS GENERALLY IN THE 60S. 79 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 87 65 86 65 / 0 5 5 10 10 WACO, TX 65 87 65 87 66 / 0 5 5 5 10 PARIS, TX 62 85 64 86 66 / 0 5 5 10 10 DENTON, TX 63 87 64 85 64 / 0 5 5 10 10 MCKINNEY, TX 61 87 64 86 65 / 0 5 5 10 10 DALLAS, TX 64 87 64 88 65 / 0 5 5 10 10 TERRELL, TX 63 88 63 86 64 / 0 5 5 10 10 CORSICANA, TX 64 88 65 87 67 / 0 5 5 5 10 TEMPLE, TX 64 86 64 86 65 / 0 5 5 5 10 MINERAL WELLS, TX 63 89 65 86 63 / 0 5 5 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1039 PM CDT FRI MAY 18 2012 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND SATURDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE CENTERED OVER SOUTH DAKOTA AND A WARM FRONT LIFTING NE OVER LAKE SUPERIOR. WITHIN THE WARM SECTOR...MOSTLY CLEAR SKIES EXIST ACROSS THE FORECAST AREA WITH ONLY THIN CIRRUS DRIFTING OVERHEAD...AHEAD OF A SHORTWAVE OVER THE PLAINS. DESPITE AWFULLY DRY AIR JUST ABOVE THE SURFACE ON THE 12Z GRB RAOB...DEWPOINTS HAVE ACTUALLY BEEN INCREASING THIS AFTERNOON AND HUMIDITY LEVELS HAVE BOTTOMED OUT IN THE MID 20 PERCENT RANGE OVER CENTRAL WISCONSIN. WITH THE UPSTREAM LOW PRESSURE BARELY REACHING THE MISSISSIPPI RIVER TOMORROW...TEMPS AND HUMIDITIES ARE THE MAIN FORECAST CONCERNS. TONIGHT...MID AND UPPER RIDGE AXIS WILL SLOWLY MOVE TO THE CENTRAL GREAT LAKES TONIGHT...WHILE A WEAK SHORTWAVE OVER THE PLAINS MOVES NE TO THE NORTHERN MISSISSIPPI VALLEY. VERY LITTLE THREAT OF PRECIP WITH THIS WAVE DUE TO THE ABUNDANCE OF DRY AIR THROUGH THE COLUMN...AND DO NOT EXPECT MORE THAN CIRRUS FLOATING OVERHEAD. OTHERWISE...HIGH PRESSURE WILL SHIFT TO THE EAST COAST AND A COLD FRONT WILL DRIFT ACROSS THE NORTHERN PLAINS. THE PRESSURE GRADIENT WILL TIGHTEN A BIT TONIGHT WHICH WILL KEEP A SOUTHERLY BREEZE IN PLACE. AS A RESULT...WILL SEE WARMER LOWS INTO THE MIDDLE AND UPPER 50S AT MOST LOCATIONS. SATURDAY...THE UPSTREAM FRONT WILL MOVE INTO WESTERN WISCONSIN BY LATE IN THE AFTERNOON. SOUTHERLY FLOW WILL STRENGTHEN A BIT BUT WILL CONTINUE TO RECYCLE A DRY AIRMASS FROM THE DEPARTING HIGH ACROSS THE STATE. SHOULD FEEL MORE HUMIDITY HOWEVER...AS THE DRY AIRMASS MODIFIES AND MOISTURE GETS PULLED NORTHWARD AHEAD OF THE FRONT. AFTER A WARMER START TO THE DAY...925MB TEMPS ARGUE FOR HIGHS IN THE MIDDLE 80S AT MOST LOCATIONS INLAND FROM LAKE MICHIGAN UNDER MOSTLY SUNNY CONDITIONS. .LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A SLOW MOVING COLD FRONT ARE THE MAIN CONCERN FOR THE EARLY PART OF THIS FORECAST. THE ECMWF IS STILL SLOWER THAN THE GFS BUT IS IT FASTER THAN YESTERDAY. POTENTIAL FOR SEVERE WEATHER WILL LIKELY HINGE ON HOW WARM IT GETS BEFORE CLOUDS ARRIVE. INSTABILITY APPEARS MODEST AND THERE ISN/T MUCH DIRECTIONAL SHEAR. SO IT DOESN/T LOOK LIKE A BIG SEVERE WEATHER DAY BUT WOULDN/T DOUBT ISOLATED STRONG OR SEVERE STORMS. SHOWERS SHOULD END MONDAY AS FRONT EXITS THE REGION. THEN NICE SEASONABLE WEATHER EXPECTED MONDAY NIGHT THROUGH THURSDAY WITH SURFACE HIGH PRESSURE IN CONTROL. BETTER GET THE AIR CONDITIONING WORKING IF THE ECMWF IS RIGHT ABOUT NEXT SATURDAY AND SUNDAY. IT BUILDS A 591 DM UPPER RIDGE OVER ILLINOIS. THIS WOULD BRING 90 DEGREE TEMPERATURES TO MUCH OF OUR AREA WITH 60F DEW POINTS. THE GFS IS FURTHER EAST WITH THE UPPER RIDGE SO WE MAY BE POSITIONED NEAR THE RING OF FIRE OF CONVECTIVE COMPLEXES WHICH WOULD KEEP TEMPERATURES DOWN A BIT. && .AVIATION...FOR 06Z TAF ISSUANCE. VFR CONDITIONS EXPECTED THROUGHOUT. SITN OVERNIGHT IS MARGINAL FOR INCLUSION OF LLWS IN THE TAFS...BUT WL CONT TO MENTION FOR WRN SITES. MODELS NOT HANDLING MN CONVECTION WELL THIS EVENING...BUT WL COUNT ON DRY SSELY FLOW HOLDING IT OFF TO THE WEST THROUGH TAF PERIOD. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1022 PM CDT FRI MAY 18 2012 .UPDATE... CURRENT WATER VAPOR LOOPS AND 500 MB ANALYSIS SHOWS SHORT WAVE THAT HELPED TRIGGER ONGOING THUNDERSTORMS IN MINNESOTA IS DAMPENING OUT AS IT TRACKS NNE FROM NW IOWA INTO SW MINNESOTA...WITH RIDGING PROTECTING SRN WI. NO CHANGES TO GOING FORECAST. 00Z/19 NAM STILL HOLDING PRECIPITATION OFF TO THE WEST WITH STRONGER 850 MB FLOW AND BEST SURFACE TO 700 MB FRONTOGENETIC FORCING ALONG AND JUST AHEAD OF SURFACE/MID LEVEL TROUGHS THROUGH THE DAY SATURDAY. SOME HINT OF PCPN BRUSHING THE NW COUNTIES OVERNIGHT SATURDAY NIGHT AS AXIS OF LOW-LEVEL JET BEGINS TO SHIFT INTO WESTERN WISCONSIN. && .AVIATION/06Z TAFS/... VFR CONDITIONS FOR THE ENTIRE FORECAST PERIOD. ONLY CONCERN IS POTENTIAL FOR LOW-LEVEL WIND SHEAR AS RAP AND LATEST NAM FORECAST SOUNDINGS INDICATE WINDS BETWEEN 28 AND 32 KNOTS AROUND 1000-1200 FT AT TOP OF INVERSION. THIS DIFFERENTIAL JUST BELOW WIND SHEAR CRITERIA...BUT WILL KEEP AN EYE ON PROFILER WINDS AND TAMDAR REPORTS FOR ANY UPWARD TREND. && .PREV DISCUSSION... /ISSUED 315 PM CDT FRI MAY 18 2012/ TONIGHT AND SATURDAY...FORECAST CONFIDENCE HIGH. LOW PRESSURE TROUGH IN THE NORTHERN PLAINS WILL GRADUALLY SHIFT EASTWARD THROUGH THE PERIOD. MEANWHILE...HIGH PRESSURE WILL REMAIN PARKED OVER THE EASTERN UNITED STATES. THE INCREASING PRESSURE GRADIENT ACROSS WISCONSIN WILL LEAD TO PERSISTENT SOUTHERLY WINDS WITH WIND GUSTS IN THE 20 TO 25 KNOT RANGE ONCE AGAIN ON SATURDAY. MIXING TO 850MB WILL ALLOW FOR LOW DEWPOINTS IN THE AFTERNOON AGAIN AS WELL. THE WARMEST TEMPS FOR THE WEEKEND ARE EXPECTED FOR SATURDAY. 925MB TEMPS WILL INCREASE ABOUT 2 DEGREES FROM TODAY TO ABOUT 24C IN SOUTH CENTRAL WI...YIELDING MAX TEMPS IN THE UPPER 80S. LOCATIONS NEAR THE LAKE WILL REACH THEIR HIGHS IN THE LOWER 80S AROUND NOON...AND THEN A LAKE BREEZE WILL DEVELOP AND DROP THE TEMPS THEREAFTER. MAX TEMPS SHOULD BE IN THE UPPER 80S NORTH OF MILWAUKEE WITH AN EARLIER SOUTHEAST WIND DEVELOPING. ANY PRECIP ASSOCIATED WITH THE APPROACHING COLD FRONT WILL HOLD OFF DURING THIS PERIOD. A FEW STREAMS OF HIGH CLOUDS WILL BE OBSERVED...BUT OTHERWISE IT WILL JUST BE TOO DRY FOR DIURNAL CUMULUS CLOUDS TO DEVELOP. SATURDAY NIGHT THROUGH SUNDAY NIGHT..FORECAST CONFIDENCE IS MEDIUM. A TROF OF LOW PRESSURE WILL BE OUT OVER THE CENTRAL PLAINS WITH RIDGING TO THE EAST EARLY IN THIS PERIOD. THE WARM SECTOR WILL BE FIRMLY IN PLACE SATURDAY NIGHT...SETTING THE STAGE FOR PRETTY MILD OVERNIGHT READINGS. WILL CARRY A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM OVER THE FAR WEST AFTER MIDNIGHT. THERE IS SOME WARM AIR ADVECTION SHOWING UP AHEAD OF THE APPROACHING TROF ALONG WITH A 35-40KT LOW LEVEL JET AND SOME UPPER LEVEL DIVERGENCE. THE MODELS ALSO DEPICT SOME HIGHER LEVEL Q-VECTOR CONVERGENCE WITH A WEAK SHORT WAVE RIDING UP HERE AHEAD OF THE MAIN TROF. JUST NOT SURE WE HAVE ENOUGH MOISTURE TO SUPPORT ANYTHING. THE FRONT WILL REACH THE WESTERN PORTION OF THE FORECAST AREA DURING MID AFTERNOON ON SUNDAY. THE NAM AND ECMWF ARE IN THE BEST AGREEMENT...WHILE THE GFS CONTINUES THE FASTER SOLUTION. SINCE THE CANADIAN SOLUTIONS LOOK CLOSER TO THE NAM/ECMWF...WILL DISCARD THE FAST GFS TIMING. SO FAIRLY QUIET YET SUNDAY MORNING...BUT EXPECT SHOWERS AND STORMS TO BE INCREASING DURING THE AFTERNOON. THUNDERSTORM PARAMETERS ARE NOT TOO IMPRESSIVE...SO NO SEVERE WEATHER IS EXPECTED. THE DEEP LAYER SHEAR IS ON THE ORDER OF 15 TO 25KTS WITH CAPE VALUES PROBABLY IN THE 1500J/KG RANGE. LOOKS LIKE PLENTY OF CLOUDINESS TO LIMIT DESTABILIZATION AS WELL. OUR IN HOUSE AGGREGATED SEVERE WEATHER PARAMETER PRODUCT SHOWS A SOLID DIMINISHING TREND WITH TIME FROM LATE MORNING THROUGH THE AFTERNOON ON SUNDAY. THE SURFACE TROF/COLD FRONT WILL BE SLOW TO EXIT AS THE ASSOCIATED UPPER SYSTEM DIGS MORE INTO THE WESTERN GREAT LAKES...RATHER THAN SCOOTING OFF TO THE EAST. THIS WILL KEEP PRECIP CHANCES IN THROUGH SUNDAY NIGHT...AND MONDAY MORNING ACROSS THE EAST. THERE IS SOME MODEL DISCREPANCY WITH HOW FAST THE PRECIP MIGHT EXIT. MONDAY AND MONDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. COOLER TEMPERATURES WILL ARRIVE IN THE WAKE OF THE COLD FRONT. HIGHS ON MONDAY SHOULD ONLY REACH THE MID TO UPPER 60S WITH A NORTH WIND AND CLOUDY SKIES. A FEW FAVORED HOT SPOTS OUT WEST COULD HIT 70. HIGH PRESSURE BUILDS IN AND WILL STICK AROUND FOR A WHILE. TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE IS HIGH. HIGH PRESSURE THIS PERIOD. QUIET WITH HIGHS IN THE 70S...WARMER WEDNESDAY VS TUESDAY. COOLER BY THE LAKE WITH A SOUTHEAST BREEZE SETTING UP AS THE HIGH IS EITHER OVERHEAD OR OFF TO OUR EAST. THURSDAY AND BEYOND...FORECAST CONFIDENCE IS MEDIUM. THE ECMWF HAS BEEN INDICATING A VERY HOT AND DRY END OF THE WEEK NEXT WEEK. IT SHOWS A MASSIVE UPPER RIDGE BUILDING OVER THE SOUTHEAST U.S. WITH SFC TEMPS POSSIBLY HITTING THE 90S FRIDAY AND SATURDAY. THE GFS HAS HAD A MUCH COOLER AND WETTER SCENARIO WITH HIGHS LIKELY ONLY IN THE 70S TO LOWER 80S. BUT...THE NEW 12Z GFS IS STARTING TO COME IN LINE WITH THE ECMWF...WITH A BUILDING UPPER RIDGE AND A DOMINANT SOUTHWEST UPPER LEVEL FLOW. IT NOW IS SUGGESTING HIGHS IN THE 80S TO POSSIBLY 90 FOR AT LEAST THE START OF THE MEMORIAL DAY WEEKEND...AND MAYBE BEYOND. THIS JUST ADDS CONFIDENCE TO A WARM MEMORIAL DAY WEEKEND...BUT IT IS A LONG WAY OFF YET. SO STAY TUNED. AVIATION/00Z TAFS/... VFR CONDITIONS WILL CONTINUE THROUGH SATURDAY...WITH ONLY SOME HIGH CLOUDS EXPECTED IN THE AREA. CLEAR SKIES AND LIGHT SOUTH WINDS TONIGHT. SOUTHERLY WINDS WILL BE IN THE 11 TO 15 KNOT RANGE WITH GUSTS TO 21 KNOTS AGAIN ON SATURDAY WITH DEEP MIXING INTO DRY AIR...ESPECIALLY INLAND. NEAR THE LAKE...LOOK FOR A LAKE BREEZE TO DEVELOP BY EARLY AFTERNOON. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...REM TONIGHT/SATURDAY AND AVIATION/MARINE...MRC SATURDAY NIGHT THROUGH FRIDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
633 PM CDT FRI MAY 18 2012 .SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT 343 PM CDT FRI MAY 18 2012 AT 3 PM...A TIGHT SURFACE PRESSURE GRADIENT HAS DEVELOPED BETWEEN A HIGH PRESSURE SYSTEM OVER NEW ENGLAND AND A LOW PRESSURE SYSTEM OVER SOUTH DAKOTA. THIS GRADIENT WAS PRODUCING SUSTAINED WINDS IN THE 15 TO 25 MPH RANGE AND WIND GUSTS AROUND 35 MPH. THE HIGHEST WIND GUSTS WERE 37 MPH AT THE ROCHESTER ASOS AND NEAR DEXTER MINNESOTA. THE COMBINATION OF SOUTHERLY WINDS AND ABUNDANT SUNSHINE HAS ALLOWED TEMPERATURES TO CLIMB TO AROUND 90 ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...AND FROM THE MID TO LOWER 90S ACROSS WESTERN WISCONSIN. THIS MAKES IT THE WARMEST DAY OF THIS YEAR IN MOST LOCATIONS. SO FAR THIS AFTERNOON...THE WARMEST TEMPERATURE REPORTED WAS 94 DEGREES FROM EYOTA /MINNESOTA DOT/. FOR TONIGHT...THE 18.12Z MODELS ARE IN VERY GOOD AGREEMENT THAT A POSITIVELY TILTED SHORT WAVE TROUGH WILL MOVE NORTHEAST THROUGH THE REGION. BUFKIT SOUNDINGS SHOW THAT THE AIR MASS BELOW 600 MB WILL REMAIN RATHER DRY. AS A RESULT...ONLY EXPECTING A SCATTERED TO OCCASIONALLY BROKEN DECK OF MID AND HIGH CLOUDS TO MOVE THROUGH THE REGION. THE GREATEST PERCENTAGE OF THESE CLOUDS WILL WEST OF THE MISSISSIPPI RIVER. ON SATURDAY...THE MAXIMUM TEMPERATURE FORECAST IS RATHER TRICKY. THIS IS DUE TO THE UNCERTAINTY ON HOW WARM THE TEMPERATURES WILL BE ALOFT /NAM HAS THE SAME TEMPERATURES AS TODAY AND THE GFS IS 2C COOLER/ AND MORE AFTERNOON CLOUDS ACROSS THE REGION. DUE TO THE LATTER...TRENDED THE FORECAST A COUPLE OF DEGREES COOLER. THE GFS DOES GENERATE PRECIPITATION NORTH OF THE INTERSTATE 94 CORRIDOR ON SATURDAY AFTERNOON. THIS IS DUE TO A STRONG PV ANOMALY MOVING NORTHEAST THROUGH THE REGION. MEANWHILE THE NAM/ECMWF/GEM HAVE A MUCH WEAKER PV ANOMALY. SINCE THE GFS IS TYPICALLY TO ROBUST WITH THESE ANOMALIES...SO OPTED TO KEEP THE FORECAST DRY. ANOTHER FORECAST ISSUE ON SATURDAY AFTERNOON WILL BE THE DEW POINTS. ALL OF THE MODELS ARE SHOWING THAT THE DEW POINTS WILL CLIMB INTO THE LOWER 60S. THIS LOOKS TO BE TOO HIGH WHEN ONE TAKES IN ACCOUNT THE DRY AIR ALOFT. THE DEW POINT MIX DOWN TOOL SUGGESTS THAT THE DEW POINTS WILL BE MORE IN THE LOWER AND MID 50S. THIS SEEMS MUCH MORE REALISTIC...THUS...WENT AT LEAST 5 TO 8F LOWER THAN THE MOS VALUES. FROM SATURDAY NIGHT INTO SUNDAY...THE MODELS CONTINUE TO STRUGGLE WITH THE TIMING OF THE COLD FRONT THROUGH THE REGION. THE GFS CONTINUES TO THE FASTEST...AND IT HAS THE FRONT THROUGH THE ENTIRE AREA BY EARLY AFTERNOON. MEANWHILE THE OTHER MODELS SUGGEST THAT THIS WILL NOT OCCUR UNTIL SUNDAY EVENING. THE MAIN DIFFERENCE IS HOW FAST THEY MOVE THE POSITIVELY TILTED SHORTWAVE TROUGH THE REGION. WITH THE GFS BEING FASTER WITH THIS FEATURE...IT MAKES SENSE THAT ITS FRONT WOULD MOVE THROUGH THE REGION FASTER. DUE TO THIS WENT WITH MORE OF BLEND FOR THE WINDS...PRECIPITATION CHANCES...AND TEMPERATURES. WITH ALL OF THE MODELS HINTING THAT THE BEST MOISTURE TRANSPORT WOULD BE MAINLY NORTH AND NORTHWEST OF THE FORECAST AREA...AS A RESULT TRENDED THE HIGHEST PRECIPITATION CHANCES FOR THESE AREAS. WHILE ML CAPES CLIMB INTO THE 1500 TO 2500 J/KG...THE 0-6 KM BULK SHEAR IS LESS THAN 30 KNOTS...SO STILL NOT THINKING THAT THERE WILL ANY SEVERE WEATHER FROM ANY OF THESE STORMS. .LONG TERM...MONDAY THROUGH FRIDAY 343 PM CDT FRI MAY 18 2012 THE 18.12Z MODELS ARE STARTING TO BECOME MORE IN AGREEMENT. THEY SHOW THAT A COLD FRONT WILL SAG SOUTHWARD INTO THE AREA ON WEDNESDAY NIGHT AND THEN LINGER ACROSS THE AREA THROUGH FRIDAY MORNING...AND THEN MOVE NORTH AS A WARM FRONT ON FRIDAY AFTERNOON AND NIGHT. THE LATTER IS ASSOCIATED WITH A RIDGE BUILDING ACROSS THE EASTERN UNITED STATES. SINCE THE LATTER HAS BEEN VERY CONSISTENT IN THE ECMWF...THERE WAS ENOUGH CONFIDENCE TO RAISE THE TEMPERATURES A COUPLE OF DEGREES ABOVE THE CONSALL FOR LATE NEXT WEEK. && .AVIATION...TONIGHT AND SATURDAY 633 PM CDT FRI MAY 18 2012 VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD...WITH JUST SOME HIGH CIRRUS FROM TIME TO TIME. WINDS WILL DIMINISH THIS EVENING BUT WILL STILL SEE SOME GUSTS AT KRST TO 20 TO 22 KNOTS THROUGHOUT THE NIGHT. BIGGEST QUESTION IS LLWS POTENTIAL AT KLSE. BOTH THE 18.18Z NAM AND 18.21Z RAP BUFKIT SOUNDINGS SHOWING WINDS INCREASING TO NEAR 35 KNOTS AROUND 1500 FEET AFTER 06Z. DEPENDING UPON HOW MUCH THE WINDS DECOUPLE IN THE VALLEY WILL DETERMINE LLWS POTENTIAL. FOR NOW WILL LEAVE OUT AND JUST MONITOR WINDS THIS EVENING. GREATEST POTENTIAL FOR LLWS WOULD BE 08Z-14Z. && .ARX WATCHES/WARNINGS/ADVISORIES... 253 PM CDT FRI MAY 18 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1224 PM CDT THU MAY 17 2012 .SHORT TERM... 1022 AM CDT THU MAY 17 2012 MAIN FORECAST CONCERNS FOR THE AFTERNOON ARE WINDS AND DEWPOINTS. 15Z SURFACE ANALYSIS SHOWS LOW PRESSURE OVER THE DAKOTAS WITH A PRESSURE FALL AREA OF NEAR 1 MB/HOUR OVER CENTRAL AND NORTHERN MINNESOTA. THIS PRESSURE FALL AREA HAS BEEN TRANSLATING EASTWARD THROUGH THE MORNING. THE PRESSURE GRADIENT HAS ALSO BEEN GRADUALLY TIGHTENING THROUGH THE MORNING FROM WESTERN IOWA THROUGH MUCH OF MINNESOTA. 12Z SOUNDING FROM MPX SHOWED A VERY DRY SOUNDING BELOW 650MB...BUT ALSO IMPORTANTLY 40 KT WINDS NEAR 950MB. A FEW SITES THAT ARE ON THE HIGHER TERRAIN JUST SOUTH OF THE MINNESOTA RIVER VALLEY HAVE BEEN EXPERIENCING WINDS OF 30 TO 40 MPH AND GUSTS NEAR 50 MPH. MEANWHILE...ALTOSTRATUS CLOUDS WITH BASES OF 9000 FT OR HIGHER HAVE BEEN PUSHING EAST ACROSS MINNESOTA AND THE NORTH HALF OF WISCONSIN...A RESULT OF ISENTROPIC LIFT IN THE WARM ADVECTION PATTERN IN PLACE AHEAD OF THE LOW. IN ADDITION...ON WATER VAPOR A SHORTWAVE TROUGH IS EVIDENT IN THE EASTERN DAKOTAS...LIKELY HELPING OUT TOO TO PRODUCE THE CLOUDS. RADAR SHOWING SOME PRECIPITATION...BUT MOST OF THIS HAS REMAINED AS VIRGA DUE TO THE DRY SUB CLOUD AIR SEEN ON THAT MPX SOUNDING. KRST JUST REPORTED A SPRINKLE...SO A LITTLE OF THIS VIRGA IS REACHING THE SURFACE. REGARDING DEWPOINTS...THEY HAVE COME UP A LITTLE BIT DUE TO THE NORMAL DIURNAL INCREASE...BUT THERE ARE LOWER ONES LURKING IN SOUTHEAST IOWA (LOW TO MID 30S THERE). WITH THE PRESSURE FALL AREA ANTICIPATED TO CONTINUE TRANSLATING EASTWARD AND THE PRESSURE GRADIENT TIGHTENING...AND ALL OF THIS HAPPENING DURING THE PEAK HEATING OF THE DAY...CONCERNED THAT WINDS COULD TRY TO PUSH ADVISORY CRITERIA. CLOUDS RIGHT NOW OVER MINNESOTA AND NORTHERN WISCONSIN ARE HOLDING MIXING DOWN SOME...BUT THESE SHOULD DISSIPATE IN THE AFTERNOON AS THE SHORTWAVE TROUGH WEAKENS AND PUSHES EAST...ALONG WITH THE ISENTROPIC LIFT SHIFTING NORTH. 06Z MAV/00Z MET GUIDANCE BOTH PUSH KRST AND KTOB TO AROUND 25 KT AT 21Z...WITH LATEST RAP GUIDANCE SUGGESTING THE SAME THING. THESE SPEEDS ARE CLOSE TO ADVISORY CRITERIA. AFTER COLLABORATION WITH MPX...DECIDED TO ERR ON THE CAUTIOUS SIDE AND ISSUE THE ADVISORY FOR SOUTHEAST MINNESOTA. TYPICALLY SOME OF NORTHEAST IOWA IS INCLUDED IN THESE ADVISORY SITUATIONS TOO...BUT IT APPEARS RIGHT NOW THAT WINDS ACROSS NORTHEAST IOWA WILL STAY BELOW ADVISORY CRITERIA. REGARDING DEWPOINTS...WITH A PERSISTENT SOUTH FLOW...CONCERNED THAT LOWER DEWPOINTS IN SOUTHEAST IOWA COULD ADVECT INTO THE FORECAST AREA. CERTAINLY THE LACK OF RAIN LATELY WOULD SUPPORT DEWPOINTS MIXING OUT...THOUGH WE HAVE GREENED UP. RAP RUNS HAVE SUGGESTED DEWPOINTS DROPPING INTO THE 20S WITH SOUNDINGS THAT SUGGEST LITTLE HELP FROM EVAPOTRANSPIRATION. MEANWHILE MOST OTHER MODELS SUGGEST UPPER 30S TO LOW 40S AT BEST. FOR NOW HAVE DISCOUNTED THE RAP RUNS...BUT LEANED TO THE LOW SIDE OF ALL OTHER GUIDANCE. WILL BE INTERESTING TO SEE HOW LOW DEWPOINTS GET TODAY. IF WE WERE NOT GREENED UP...TODAY WOULD BE CONCERNING FOR FIRE WEATHER. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 315 AM CDT THU MAY 17 2012 17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE SATURDAY NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF THE TWO MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF TIL EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS APPROACH GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE FOR STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR DEPICTED BY THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS RESOLVED A BIT BETTER WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP DIFFERENCES GOING THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS MAINTAINING A MORE PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF. ECMWF KEEPS TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY NIGHT THROUGH TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED THUNDER. THE GFS BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER SOLUTION. WILL KEEP MODEL CONSENSUS GOING HERE AS WELL DUE TO THE UNCERTAINTY. UPPER/SURFACE FLOW BECOMES SOUTHERLY ON WEDNESDAY WITH BOTH MODELS SHOWING A WEAK EMBEDDED WAVE ALOFT. THE ECMWF SHOWS LIGHT QPF SIGNAL WITH THIS FEATURE WHILE THE GFS REMAINS DRY. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS/THUNDER FOR NOW. OTHERWISE...LOOKS LIKE TEMPERATURES WILL START OFF SOME 10 DEGREES ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER 80S...THEN NEAR NORMAL IN THE 70S MON/TUE/WED. && .AVIATION...THROUGH 18Z FRIDAY 1224 PM CDT THU MAY 17 2012 A PERSISTENT SOUTHERLY FLOW OF DRY AIR WILL HELP TO MAINTAIN VFR CONDITIONS THROUGH THE FRIDAY. THE BIGGER ISSUE IS WINDS. A TIGHT PRESSURE GRADIENT IN PLACE AHEAD OF LOW PRESSURE IN THE DAKOTAS HAS ALREADY RESULTED IN GUSTS BETWEEN 20-30 KT AT BOTH TAF SITES. LOOK FOR THE GUSTS AS WELL AS SUSTAINED SPEEDS TO INCREASE A LITTLE MORE THIS AFTERNOON WITH DAYTIME HEATING. WINDS SHOULD COME DOWN SOME THIS EVENING WITH LOSS OF HEATING...BUT A STRONG LOW LEVEL JET COMING ACROSS TONIGHT SHOULD KEEP KRST GUSTY THROUGH MUCH OF THE NIGHT. WITH KLSE IN THE VALLEY...FAVORING LIGHTER WINDS AT THE SURFACE...HAVE INCLUDED LOW LEVEL WIND SHEAR FOR THE LOW LEVEL JET. PLAN ON SOUTHERLY WINDS TO PICK BACK UP FRIDAY MORNING WITHIN A FEW HOURS OF SUNRISE DUE TO MIXING. WINDS ON FRIDAY DO NOT LOOK AS STRONG AS TODAY...DUE TO A WEAKER PRESSURE GRADIENT FORECAST...BUT SUSTAINED SPEEDS OF 15 KT WITH GUSTS TO 25 KT OR SO LOOK LIKELY. && .ARX WATCHES/WARNINGS/ADVISORIES... 1022 AM CDT THU MAY 17 2012 WI...NONE. MN...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING FOR MNZ079-086-087-094-095. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...DAS AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1022 AM CDT THU MAY 17 2012 .SHORT TERM... 1022 AM CDT THU MAY 17 2012 MAIN FORECAST CONCERNS FOR THE AFTERNOON ARE WINDS AND DEWPOINTS. 15Z SURFACE ANALYSIS SHOWS LOW PRESSURE OVER THE DAKOTAS WITH A PRESSURE FALL AREA OF NEAR 1 MB/HOUR OVER CENTRAL AND NORTHERN MINNESOTA. THIS PRESSURE FALL AREA HAS BEEN TRANSLATING EASTWARD THROUGH THE MORNING. THE PRESSURE GRADIENT HAS ALSO BEEN GRADUALLY TIGHTENING THROUGH THE MORNING FROM WESTERN IOWA THROUGH MUCH OF MINNESOTA. 12Z SOUNDING FROM MPX SHOWED A VERY DRY SOUNDING BELOW 650MB...BUT ALSO IMPORTANTLY 40 KT WINDS NEAR 950MB. A FEW SITES THAT ARE ON THE HIGHER TERRAIN JUST SOUTH OF THE MINNESOTA RIVER VALLEY HAVE BEEN EXPERIENCING WINDS OF 30 TO 40 MPH AND GUSTS NEAR 50 MPH. MEANWHILE...ALTOSTRATUS CLOUDS WITH BASES OF 9000 FT OR HIGHER HAVE BEEN PUSHING EAST ACROSS MINNESOTA AND THE NORTH HALF OF WISCONSIN...A RESULT OF ISENTROPIC LIFT IN THE WARM ADVECTION PATTERN IN PLACE AHEAD OF THE LOW. IN ADDITION...ON WATER VAPOR A SHORTWAVE TROUGH IS EVIDENT IN THE EASTERN DAKOTAS...LIKELY HELPING OUT TOO TO PRODUCE THE CLOUDS. RADAR SHOWING SOME PRECIPITATION...BUT MOST OF THIS HAS REMAINED AS VIRGA DUE TO THE DRY SUB CLOUD AIR SEEN ON THAT MPX SOUNDING. KRST JUST REPORTED A SPRINKLE...SO A LITTLE OF THIS VIRGA IS REACHING THE SURFACE. REGARDING DEWPOINTS...THEY HAVE COME UP A LITTLE BIT DUE TO THE NORMAL DIURNAL INCREASE...BUT THERE ARE LOWER ONES LURKING IN SOUTHEAST IOWA (LOW TO MID 30S THERE). WITH THE PRESSURE FALL AREA ANTICIPATED TO CONTINUE TRANSLATING EASTWARD AND THE PRESSURE GRADIENT TIGHTENING...AND ALL OF THIS HAPPENING DURING THE PEAK HEATING OF THE DAY...CONCERNED THAT WINDS COULD TRY TO PUSH ADVISORY CRITERIA. CLOUDS RIGHT NOW OVER MINNESOTA AND NORTHERN WISCONSIN ARE HOLDING MIXING DOWN SOME...BUT THESE SHOULD DISSIPATE IN THE AFTERNOON AS THE SHORTWAVE TROUGH WEAKENS AND PUSHES EAST...ALONG WITH THE ISENTROPIC LIFT SHIFTING NORTH. 06Z MAV/00Z MET GUIDANCE BOTH PUSH KRST AND KTOB TO AROUND 25 KT AT 21Z...WITH LATEST RAP GUIDANCE SUGGESTING THE SAME THING. THESE SPEEDS ARE CLOSE TO ADVISORY CRITERIA. AFTER COLLABORATION WITH MPX...DECIDED TO ERR ON THE CAUTIOUS SIDE AND ISSUE THE ADVISORY FOR SOUTHEAST MINNESOTA. TYPICALLY SOME OF NORTHEAST IOWA IS INCLUDED IN THESE ADVISORY SITUATIONS TOO...BUT IT APPEARS RIGHT NOW THAT WINDS ACROSS NORTHEAST IOWA WILL STAY BELOW ADVISORY CRITERIA. REGARDING DEWPOINTS...WITH A PERSISTENT SOUTH FLOW...CONCERNED THAT LOWER DEWPOINTS IN SOUTHEAST IOWA COULD ADVECT INTO THE FORECAST AREA. CERTAINLY THE LACK OF RAIN LATELY WOULD SUPPORT DEWPOINTS MIXING OUT...THOUGH WE HAVE GREENED UP. RAP RUNS HAVE SUGGESTED DEWPOINTS DROPPING INTO THE 20S WITH SOUNDINGS THAT SUGGEST LITTLE HELP FROM EVAPOTRANSPIRATION. MEANWHILE MOST OTHER MODELS SUGGEST UPPER 30S TO LOW 40S AT BEST. FOR NOW HAVE DISCOUNTED THE RAP RUNS...BUT LEANED TO THE LOW SIDE OF ALL OTHER GUIDANCE. WILL BE INTERESTING TO SEE HOW LOW DEWPOINTS GET TODAY. IF WE WERE NOT GREENED UP...TODAY WOULD BE CONCERNING FOR FIRE WEATHER. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 315 AM CDT THU MAY 17 2012 17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE SATURDAY NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF THE TWO MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF TIL EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS APPROACH GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE FOR STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR DEPICTED BY THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS RESOLVED A BIT BETTER WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP DIFFERENCES GOING THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS MAINTAINING A MORE PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF. ECMWF KEEPS TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY NIGHT THROUGH TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED THUNDER. THE GFS BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER SOLUTION. WILL KEEP MODEL CONSENSUS GOING HERE AS WELL DUE TO THE UNCERTAINTY. UPPER/SURFACE FLOW BECOMES SOUTHERLY ON WEDNESDAY WITH BOTH MODELS SHOWING A WEAK EMBEDDED WAVE ALOFT. THE ECMWF SHOWS LIGHT QPF SIGNAL WITH THIS FEATURE WHILE THE GFS REMAINS DRY. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS/THUNDER FOR NOW. OTHERWISE...LOOKS LIKE TEMPERATURES WILL START OFF SOME 10 DEGREES ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER 80S...THEN NEAR NORMAL IN THE 70S MON/TUE/WED. && .AVIATION...TODAY AND TONIGHT 618 AM CDT THU MAY 17 2012 BREEZY VFR CONDITIONS EXPECTED THROUGH THE PERIOD. AS A STORM SYSTEM DEVELOPS OVER SOUTH DAKOTA TODAY...THE GRADIENT WILL TIGHTEN OVER THE REGION. THIS WILL PRODUCE SOUTH WINDS AT BOTH TAF SITES WITH SUSTAINED SPEEDS AROUND 20 KNOTS. GUSTS WILL DEVELOP BY MID TO LATE MORNING AND CONTINUE INTO THE EARLY EVENING. KLSE SHOULD GUST TO AROUND 25 KNOTS WITH GUSTS TO AROUND 30 KNOTS EXPECTED AT KRST. THE GUSTS SHOULD DIMINISH BY EARLY EVENING BUT LOOK FOR SUSTAINED SPEEDS TO REMAIN BETWEEN 10 AND 15 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... 1022 AM CDT THU MAY 17 2012 WI...NONE. MN...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING FOR MNZ079-086-087-094-095. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...DAS AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT THU MAY 17 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY 315 AM CDT THU MAY 17 2012 FORECAST CONCERNS INCLUDE SHRA CHANCES ACROSS THE NORTH TODAY AND THEN INCREASING WARMTH THROUGH THE REMAINDER OF THE PERIOD. LATEST WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW RIDGING OVER THE IMMEDIATE FORECAST AREA WITH A WEAK MID-LEVEL TROUGH OVER THE NORTHERN PLAINS. SURFACE ANALYSIS AT 3 AM HAS HIGH PRESSURE OVER THE GREAT LAKES REGION WITH AN AREA OF LOW PRESSURE OVER THE NORTHERN PLAINS. A WARM FRONT EXTENDED FROM THIS LOW EAST-SOUTHEASTWARD ACROSS SOUTHERN MN INTO NORTHEAST IA. MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE WARM FRONT WAS PRODUCING SOME VERY HIGH-BASED SHRA/ISOLATED THUNDER ACROSS CENTRAL SD INTO FAR SOUTHWEST MN. 17.00Z NCEP MODELS/17.21Z SREF IN GOOD AGREEMENT WITH OVERALL SYNOPTIC SETUP THROUGH THE PERIOD. FOR TODAY...LOW PRESSURE WILL STAY PUT ACROSS THE NORTHERN PLAINS AS THE WARM FRONT LIFTS NORTH INTO CENTRAL MN/NORTHERN WI BY EARLY THIS EVENING. AXIS OF LIGHT TO MODERATE 925-850MB MOISTURE TRANSPORT STAYS NORTH OF THE AREA WITH BULK FAIRLY STRONG ISENTROPIC LIFT FOLLOWING SUIT. EITHER WAY...LOWEST 700-600MB VERY DRY AS EVIDENCED BY THE 17.00Z MPX SOUNDING AND NAM BUFKIT SOUNDINGS. MOST SHRA ACTIVITY WILL BE FALLING OUT OF ACCAS CLOUD AT OR ABOVE 10-12KFT. WOULD TAKE VIGOROUS CONVECTION FOR ANYTHING TO REACH THE GROUND. AS SUCH...HAVE TRIMMED POPS FARTHER NORTH AND KEPT A SMALL CHANCE OF SHRA/ISOLD THUNDER CONFINED NORTH OF HIGHWAY 10 IN WISCONSIN. OTHERWISE...LOOK FOR INCREASING SOUTH WINDS TODAY WITH INCREASING PRESSURE GRADIENT. WINDS ACROSS MUCH OF THE AREA SHOULD BE IN THE 15-25 MPH RANGE...BUT THE HIGHER/MORE WIND-PRONE AREAS OF SOUTHEAST MN/NORTHEAST IA WILL LIKELY SEE WINDS MORE IN THE 20-25 MPH RANGE WITH GUSTS AROUND 35 MPH. WITH WARM ADVECTION/RISING MOTIONS IN THE BOUNDARY LAYER MITIGATING DOWNWARD TRANSFER OF STRONGER WINDS ALOFT...FEEL WINDS WILL BE JUST SHY OF WIND ADVISORY. WILL HAVE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES ARE EXPECTED TO RESPOND TO INCREASING SOUTHERLY FLOW WITH AFTERNOON HIGHS TOPPING OFF IN THE UPPER 60S ACROSS NORTHERN WISCONSIN...TO THE MID-UPPER 70S ELSEWHERE. WARM FRONT PUSHES NORTH OF THE AREA THIS EVENING WITH A STRONG CAP SETTING UP ACROSS THE AREA IN THE WARM SECTOR ON FRIDAY. WITH MOSTLY SUNNY SKIES AND STRONG SOUTHERLY FLOW...TEMPERATURES SHOULD HAVE NO PROBLEM REACHING INTO THE UPPER 70S TO MIDDLE 80S. DEW POINTS WILL ALSO BE ON THE RISE INTO THE 50S FOR A SLIGHTLY MORE MUGGY FEEL COMPARED TO THE LAST FEW DAYS. COLD FRONT AND ASSOCIATED CONVECTION OVER THE NORTHERN PLAINS MAKES A MOVE EASTWARD INTO MN/WESTERN IA ON SATURDAY WITH CAP HOLDING FIRM ACROSS OUR FORECAST AREA. CONTINUED STRONG SOUTHERLY FLOW AND PARTLY TO MOSTLY SUNNY SKIES SHOULD PUSH TEMPERATURES INTO THE MID-UPPER 80S. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 315 AM CDT THU MAY 17 2012 17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE SATURDAY NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF THE TWO MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF TIL EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS APPROACH GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE FOR STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR DEPICTED BY THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS RESOLVED A BIT BETTER WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP DIFFERENCES GOING THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS MAINTAINING A MORE PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF. ECMWF KEEPS TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY NIGHT THROUGH TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED THUNDER. THE GFS BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER SOLUTION. WILL KEEP MODEL CONSENSUS GOING HERE AS WELL DUE TO THE UNCERTAINTY. UPPER/SURFACE FLOW BECOMES SOUTHERLY ON WEDNESDAY WITH BOTH MODELS SHOWING A WEAK EMBEDDED WAVE ALOFT. THE ECMWF SHOWS LIGHT QPF SIGNAL WITH THIS FEATURE WHILE THE GFS REMAINS DRY. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS/THUNDER FOR NOW. OTHERWISE...LOOKS LIKE TEMPERATURES WILL START OFF SOME 10 DEGREES ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER 80S...THEN NEAR NORMAL IN THE 70S MON/TUE/WED. && .AVIATION...TODAY AND TONIGHT 618 AM CDT THU MAY 17 2012 BREEZY VFR CONDITIONS EXPECTED THROUGH THE PERIOD. AS A STORM SYSTEM DEVELOPS OVER SOUTH DAKOTA TODAY...THE GRADIENT WILL TIGHTEN OVER THE REGION. THIS WILL PRODUCE SOUTH WINDS AT BOTH TAF SITES WITH SUSTAINED SPEEDS AROUND 20 KNOTS. GUSTS WILL DEVELOP BY MID TO LATE MORNING AND CONTINUE INTO THE EARLY EVENING. KLSE SHOULD GUST TO AROUND 25 KNOTS WITH GUSTS TO AROUND 30 KNOTS EXPECTED AT KRST. THE GUSTS SHOULD DIMINISH BY EARLY EVENING BUT LOOK FOR SUSTAINED SPEEDS TO REMAIN BETWEEN 10 AND 15 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... 315 AM CDT THU MAY 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 AM CDT THU MAY 17 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY 315 AM CDT THU MAY 17 2012 FORECAST CONCERNS INCLUDE SHRA CHANCES ACROSS THE NORTH TODAY AND THEN INCREASING WARMTH THROUGH THE REMAINDER OF THE PERIOD. LATEST WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW RIDGING OVER THE IMMEDIATE FORECAST AREA WITH A WEAK MID-LEVEL TROUGH OVER THE NORTHERN PLAINS. SURFACE ANALYSIS AT 3 AM HAS HIGH PRESSURE OVER THE GREAT LAKES REGION WITH AN AREA OF LOW PRESSURE OVER THE NORTHERN PLAINS. A WARM FRONT EXTENDED FROM THIS LOW EAST-SOUTHEASTWARD ACROSS SOUTHERN MN INTO NORTHEAST IA. MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND OVER THE WARM FRONT WAS PRODUCING SOME VERY HIGH-BASED SHRA/ISOLATED THUNDER ACROSS CENTRAL SD INTO FAR SOUTHWEST MN. 17.00Z NCEP MODELS/17.21Z SREF IN GOOD AGREEMENT WITH OVERALL SYNOPTIC SETUP THROUGH THE PERIOD. FOR TODAY...LOW PRESSURE WILL STAY PUT ACROSS THE NORTHERN PLAINS AS THE WARM FRONT LIFTS NORTH INTO CENTRAL MN/NORTHERN WI BY EARLY THIS EVENING. AXIS OF LIGHT TO MODERATE 925-850MB MOISTURE TRANSPORT STAYS NORTH OF THE AREA WITH BULK FAIRLY STRONG ISENTROPIC LIFT FOLLOWING SUIT. EITHER WAY...LOWEST 700-600MB VERY DRY AS EVIDENCED BY THE 17.00Z MPX SOUNDING AND NAM BUFKIT SOUNDINGS. MOST SHRA ACTIVITY WILL BE FALLING OUT OF ACCAS CLOUD AT OR ABOVE 10-12KFT. WOULD TAKE VIGOROUS CONVECTION FOR ANYTHING TO REACH THE GROUND. AS SUCH...HAVE TRIMMED POPS FARTHER NORTH AND KEPT A SMALL CHANCE OF SHRA/ISOLD THUNDER CONFINED NORTH OF HIGHWAY 10 IN WISCONSIN. OTHERWISE...LOOK FOR INCREASING SOUTH WINDS TODAY WITH INCREASING PRESSURE GRADIENT. WINDS ACROSS MUCH OF THE AREA SHOULD BE IN THE 15-25 MPH RANGE...BUT THE HIGHER/MORE WIND-PRONE AREAS OF SOUTHEAST MN/NORTHEAST IA WILL LIKELY SEE WINDS MORE IN THE 20-25 MPH RANGE WITH GUSTS AROUND 35 MPH. WITH WARM ADVECTION/RISING MOTIONS IN THE BOUNDARY LAYER MITIGATING DOWNWARD TRANSFER OF STRONGER WINDS ALOFT...FEEL WINDS WILL BE JUST SHY OF WIND ADVISORY. WILL HAVE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES ARE EXPECTED TO RESPOND TO INCREASING SOUTHERLY FLOW WITH AFTERNOON HIGHS TOPPING OFF IN THE UPPER 60S ACROSS NORTHERN WISCONSIN...TO THE MID-UPPER 70S ELSEWHERE. WARM FRONT PUSHES NORTH OF THE AREA THIS EVENING WITH A STRONG CAP SETTING UP ACROSS THE AREA IN THE WARM SECTOR ON FRIDAY. WITH MOSTLY SUNNY SKIES AND STRONG SOUTHERLY FLOW...TEMPERATURES SHOULD HAVE NO PROBLEM REACHING INTO THE UPPER 70S TO MIDDLE 80S. DEW POINTS WILL ALSO BE ON THE RISE INTO THE 50S FOR A SLIGHTLY MORE MUGGY FEEL COMPARED TO THE LAST FEW DAYS. COLD FRONT AND ASSOCIATED CONVECTION OVER THE NORTHERN PLAINS MAKES A MOVE EASTWARD INTO MN/WESTERN IA ON SATURDAY WITH CAP HOLDING FIRM ACROSS OUR FORECAST AREA. CONTINUED STRONG SOUTHERLY FLOW AND PARTLY TO MOSTLY SUNNY SKIES SHOULD PUSH TEMPERATURES INTO THE MID-UPPER 80S. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 315 AM CDT THU MAY 17 2012 17.00Z ECMWF/GFS STILL SHOWING DIFFERENCE IN TIMING OF THE COLD FRONTAL PASSAGE ACROSS THE AREA/ASSOCIATED SHRA/TS CHANCES IN THE SATURDAY NIGHT/SUNDAY TIME FRAME. THE GFS REMAINS THE FASTER OF THE TWO MODELS WITH PASSAGE AROUND 18Z WHEREAS THE ECMWF HOLDS OFF TIL EVENING. WITH THIS UNCERTAINTY...WILL KEEP MODEL CONSENSUS APPROACH GOING FOR NOW. WITH SLOWER TIMING...THERE STANDS A CHANCE FOR STRONG/SEVERE THUNDERSTORMS WITH AMPLE CAPE/BULK SHEAR DEPICTED BY THE ECMWF. HOPEFULLY THE MODELS WILL HAVE THIS RESOLVED A BIT BETTER WITHIN THE NEXT FEW RUNS. MODELS THEN KEEP DIFFERENCES GOING THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS MAINTAINING A MORE PROGRESSIVE WAVE PATTERN COMPARED TO THE ECMWF. ECMWF KEEPS TROUGH/COOLER CYCLONIC FLOW AROUND THE AREA SUNDAY NIGHT THROUGH TUESDAY FOR A SMALL CHANCE OF SHOWERS/ISOLATED THUNDER. THE GFS BRINGS RIDGING IN FAIRLY QUICK FOR A DRIER SOLUTION. WILL KEEP MODEL CONSENSUS GOING HERE AS WELL DUE TO THE UNCERTAINTY. UPPER/SURFACE FLOW BECOMES SOUTHERLY ON WEDNESDAY WITH BOTH MODELS SHOWING A WEAK EMBEDDED WAVE ALOFT. THE ECMWF SHOWS LIGHT QPF SIGNAL WITH THIS FEATURE WHILE THE GFS REMAINS DRY. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS/THUNDER FOR NOW. OTHERWISE...LOOKS LIKE TEMPERATURES WILL START OFF SOME 10 DEGREES ABOVE NORMAL ON SUNDAY IN THE MID 70-LOWER 80S...THEN NEAR NORMAL IN THE 70S MON/TUE/WED. && .AVIATION...THROUGH 06Z FRIDAY 1151 PM CDT WED MAY 16 2012 VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WINDS WILL CONTINUE TO SWING AROUND TO THE SOUTH OVERNIGHT AS THE SURFACE HIGH SLIDES EASTWARD. MOISTURE TRANSPORT WILL NOSE INTO WESTERN MINNESOTA BETWEEN 09Z-12Z TONIGHT WHICH WILL RESULT IN SOME SHOWERS. THESE SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO LIFT EAST-NORTHEAST AND REMAIN NORTH OF THE TAF SITES THROUGH THURSDAY. 17.01Z HRRR DOES SHOW THE SHOWERS JUST SKIRTING KRST...BUT WILL LEAVE ANY MENTION OUT OF THE FORECAST AT THIS TIME...WITH ONLY A SCT-BKN BAND OF MID LEVEL CLOUDS. PRESSURE GRADIENT WILL TIGHTEN LATE THIS MORNING...BETWEEN 15Z-18Z WITH SOUTH WINDS INCREASING WITH SOME GUSTS TO BETWEEN 25 AND 35 KNOTS. WINDS WILL SUBSIDE AFTER 00Z...BUT STILL REMAIN ABOVE 12 KNOTS AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... 315 AM CDT THU MAY 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 PM CDT WED MAY 16 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY 237 PM CDT WED MAY 16 2012 MAIN FORECAST CONCERNS ARE ON BREEZY SOUTH WINDS ON THURSDAY ALONG WITH SHOWER CHANCES ACROSS PORTIONS OF SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. FOCUS THEN TURNS TO TEMPERATURES FRIDAY INTO SATURDAY. AT 235 PM...SURFACE ANALYSIS PLACED A SURFACE RIDGE OF HIGH PRESSURE CENTERED OVER THE UPPER MISSISSIPPI RIVER VALLEY. SKIES WERE SUNNY ACROSS THE FORECAST AREA WITH AFTERNOON TEMPERATURES RANGING FROM THE LOWER 60S ACROSS NORTH CENTRAL WISCONSIN TO AROUND 70 ACROSS NORTHEAST IOWA. THE HIGH WILL SLIDE EAST OF THE FORECAST AREA TONIGHT AS A TROUGH DIGS INTO THE WESTERN CONUS. SURFACE LOW PRESSURE NEAR THE MONTANA/SASKATCHEWAN BORDER WILL DEEPEN TONIGHT. A SURFACE TROUGH IS EXPECTED TO EXTEND SOUTH THROUGH THE WESTERN DAKOTAS/NEBRASKA PANHANDLE INTO EASTERN COLORADO. SOUTHERLY FLOW WILL INCREASE ACROSS THE FORECAST AREA AHEAD OF THIS SYSTEM LATE TONIGHT INTO EARLY THURSDAY MORNING AS A WARM FRONT PUSHES EAST ACROSS MINNESOTA...AND IS EXPECTED TO BE POSITIONED ALONG THE MISSISSIPPI RIVER AROUND 12Z. 850 MB MOISTURE TRANSPORT WILL BE FOCUSED INTO NORTHERN MINNESOTA/NORTHWEST WISCONSIN THROUGH MUCH OF THE DAY ON THURSDAY SO WOULD EXPECT THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THESE AREAS. CANNOT RULE OUT A FEW SPRINKLES OR LIGHT RAIN SHOWERS ACROSS NORTH CENTRAL INTO WEST CENTRAL WISCONSIN LATE THURSDAY MORNING INTO THURSDAY AFTERNOON AS A WEAK UPPER LEVEL SHORTWAVE MOVES EAST ACROSS CENTRAL MINNESOTA INTO CENTRAL WISCONSIN. FORECAST SOUNDINGS SHOW A VERY DRY LAYER FROM THE SURFACE THROUGH 600 MB. PRECIPITATION WILL HAVE A TOUGH TIME MAKING IT THROUGH THIS LAYER. SHOULD SEE MAINLY A MID CLOUD DECK OR POSSIBLY SOME ALTOCUMULUS CASTELLANAS/ACCAS/ THURSDAY MORNING INTO THURSDAY AFTERNOON. WILL MAINTAIN SHOWER CHANCES ACROSS PORTIONS OF SOUTHEAST MINNESOTA AND NORTH CENTRAL INTO WEST CENTRAL WISCONSIN TO ACCOUNT FOR A FEW LIGHT SHOWERS OR SPRINKLES. FORECAST SOUNDINGS ACROSS NORTH CENTRAL WISCONSIN INDICATING AROUND 277 J/KG ELEVATED CAPE LIFTING FROM 600 THROUGH 300 MB...SO WOULD EXPECT THIS INSTABILITY GO INTO ACCAS PRODUCTION. MUCH WARMER AIR WILL MOVE INTO THE REGION BEHIND THE FRONT WITH 850 MB TEMPERATURES WARMING TO AROUND 17 C BY LATE THURSDAY AFTERNOON. HIGHS WILL CLIMB INTO THE UPPER 70S TO AROUND 80 ACROSS SOUTHEAST MINNESOTA INTO NORTHEAST IOWA...WITH HIGHS RANGING FROM THE UPPER 60S ACROSS NORTH CENTRAL WISCONSIN TO THE UPPER 70S ACROSS FAR SOUTHWEST WISCONSIN. IT WILL BE RATHER BREEZY ON THURSDAY...ESPECIALLY ACROSS THE OPEN AREAS OF SOUTHEAST MINNESOTA/NORTHEAST IOWA...AND THE BLUFF TOPS ACROSS WESTERN WISCONSIN...WHERE SUSTAINED SOUTH WINDS OF 20 TO 25 MPH ARE EXPECTED WITH GUSTS AROUND 44 MPH POSSIBLE DURING PEAK HEATING. IT APPEARS THE WINDS WILL BE JUST SHY OF WIND ADVISORY CRITERIA SO WILL HOLD OFF ON ISSUING AN ADVISORY. HOWEVER...WILL BE INCREASING WIND SPEEDS ACROSS MUCH OF THE FORECAST AREA. THE WARM FRONT WILL LIFT INTO UPPER MICHIGAN AND EXTREME NORTHERN MINNESOTA THURSDAY EVENING. SHOWER AND THUNDERSTORM CHANCES WILL SHIFT NORTH OF THE FORECAST AREA AS 850 MB MOISTURE TRANSPORT REMAINS FOCUSES NORTH AND WEST OF THE AREA. IN ADDITION...UPPER LEVEL RIDGING WILL BE BUILDING ACROSS THE FORECAST AREA...WITH NO APPRECIABLE UPPER LEVEL FORCING TO GENERATE PRECIPITATION. UNDER MOSTLY CLEAR SKIES...SOUTHERLY WINDS WILL KEEP TEMPERATURES ON THE MILD SIDE THURSDAY NIGHT WITH LOWS RANGING FROM THE LOWER 60S ACROSS SOUTHEAST MINNESOTA INTO NORTHEAST IOWA...TO THE MID 50S ACROSS CENTRAL INTO FAR SOUTHWEST WISCONSIN. A WARM DAY IS ON TAP FOR THE REGION ON FRIDAY WITH HIGHS RANGING FROM THE LOWER 80S ACROSS NORTH CENTRAL WISCONSIN TO THE UPPER 80S ACROSS NORTHEAST IOWA. IN ADDITION...HIGHER DEWPOINTS WILL MAKE A RETURN TO THE AREA WITH DEWPOINTS CLIMBING INTO THE UPPER 50S TO LOWER 60S. THE COMBINATION OF THESE TEMPERATURES AND DEWPOINTS WILL MAKE IT FEEL A LITTLE ON THE MUGGY SIDE COMPARED TO THE DRY AIR WE EXPERIENCED THIS PAST WEEK. ANOTHER BREEZY DAY IS EXPECTED WITH SOUTH WINDS IN THE 15 TO 20 MPH RANGE...POSSIBLY GUSTING TO AROUND 30 MPH AT TIMES IN THE OPEN AREAS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THE TROUGH OVER THE WESTERN US WILL MOVE EAST INTO THE PLAINS FRIDAY NIGHT INTO SATURDAY WITH THE SURFACE LOW LIFTING NORTH OUT OF THE DAKOTAS INTO WESTERN ONTARIO. A COLD FRONT WILL DRIFT INTO WESTERN MINNESOTA BY LATE SATURDAY AFTERNOON WITH SHOWERS/THUNDERSTORMS EXPECTED AHEAD OF THE FRONT. ANOTHER WARM DAY IS EXPECTED ACROSS THE FORECAST AREA WITH HIGHS CLIMBING INTO THE MID TO UPPER 80S UNDER PARTLY SUNNY SKIES. IN ADDITION...DEWPOINTS WILL REMAIN IN THE UPPER 50S TO LOWER 60S MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE COLD FRONT IS EXPECTED TO REMAIN WEST OF THE FORECAST AREA ON SATURDAY. AFTERNOON MUCAPE VALUES INCREASING INTO THE 1500 TO 2000 J/KG RANGE. FORECAST SOUNDINGS SHOW A WEAK CAP IN PLACE BY SATURDAY AFTERNOON. NOT EXPECTING TO SEE MUCH DEVELOPMENT WITH VIRTUALLY NO FORCING TO HELP SPARK SHOWERS/THUNDERSTORM UNTIL THE COLD FRONT MOVES IN. EVEN IF STORMS COULD DEVELOP...SHEAR IS VERY WEAK SO WOULD NOT EXPECT TO SEE SEVERE THUNDERSTORMS DURING THE DAY ON SATURDAY. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY 237 PM CDT WED MAY 16 2012 16.12 FORECAST MODELS SHOWING SOME SLIGHT DIFFERENCES IN TIMING OF THE COLD FRONT MOVING THROUGH THE FORECAST AREA SATURDAY NIGHT THROUGH SUNDAY. THE GFS/GEM ARE THE FASTER SOLUTIONS...BRINGING THE FRONT THROUGH THE FORECAST AREA LATE SATURDAY NIGHT INTO EARLY SUNDAY AFTERNOON. THE ECMWF IS A LITTLE SLOWER...BRINGING THE FRONT THROUGH THE AREA LATE SUNDAY AFTERNOON INTO SUNDAY EVENING. 0-6 KM BULK SHEAR VALUES INCREASE ACROSS THE AREA SATURDAY NIGHT THROUGH SUNDAY INTO THE 30 TO 35 KT RANGE. DEPENDING ON THE TIMING OF THE FRONT STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE BUT DO NOT APPEAR LIKELY AT THIS TIME. GIVEN THE UNCERTAINTY ON EXACTLY WHEN THE FRONT WILL MOVE THROUGH...ITS DIFFICULT TO PIN DOWN EXACT SEVERE WEATHER THREATS AT THIS TIME IF IT OCCURS. WEAK HIGH PRESSURE WILL BUILD INTO THE REGION BEHIND THE FRONT MONDAY NIGHT INTO TUESDAY. LOOK FOR HIGHS TO FALL BACK INTO THE 70S ON MONDAY. THE HIGH LOOKS TO SLIDE EAST OF THE AREA TUESDAY NIGHT INTO WEDNESDAY AS A TROUGH MOVES ACROSS THE PACIFIC NORTHWEST AND PUSHES EAST THROUGH THE DAKOTAS ON TUESDAY NIGHT INTO WEDNESDAY. SOUTHERLY FLOW WILL INCREASE AHEAD OF THIS SYSTEM PUMPING MOIST UNSTABLE AIR BACK INTO THE REGION. FLOW ALOFT LOOKS TO TURN SOUTHWEST ON WEDNESDAY AS THE TROUGH PUSHES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. EMBEDDED SHORTWAVE COULD TRIGGER SHOWERS AND THUNDERSTORMS ACROSS THE REGION WEDNESDAY INTO WEDNESDAY NIGHT. MODELS ARE HINTING AT AN ACTIVE PATTERN TO END THE WEEK BUT WILL HAVE TO TAKE A CLOSER LOOK AT THIS WITH LATER MODEL RUNS. && .AVIATION...THROUGH 06Z FRIDAY 1151 PM CDT WED MAY 16 2012 VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WINDS WILL CONTINUE TO SWING AROUND TO THE SOUTH OVERNIGHT AS THE SURFACE HIGH SLIDES EASTWARD. MOISTURE TRANSPORT WILL NOSE INTO WESTERN MINNESOTA BETWEEN 09Z-12Z TONIGHT WHICH WILL RESULT IN SOME SHOWERS. THESE SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO LIFT EAST-NORTHEAST AND REMAIN NORTH OF THE TAF SITES THROUGH THURSDAY. 17.01Z HRRR DOES SHOW THE SHOWERS JUST SKIRTING KRST...BUT WILL LEAVE ANY MENTION OUT OF THE FORECAST AT THIS TIME...WITH ONLY A SCT-BKN BAND OF MID LEVEL CLOUDS. PRESSURE GRADIENT WILL TIGHTEN LATE THIS MORNING...BETWEEN 15Z-18Z WITH SOUTH WINDS INCREASING WITH SOME GUSTS TO BETWEEN 25 AND 35 KNOTS. WINDS WILL SUBSIDE AFTER 00Z...BUT STILL REMAIN ABOVE 12 KNOTS AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... 237 PM CDT WED MAY 16 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DENVER CO
353 AM MDT SAT MAY 19 2012 .SHORT TERM...WATER VAPOR IMAGERY SHOWING UPPER LOW NOW MOVING ACROSS WESTERN COLORADO WITH SCATTERED SHOWERS INCREASING ACROSS THE NORTHERN MOUNTAINS ATTM. RUC QG ANALYSIS SHOWING WEAK TO MODERATE ASCENT NOW INTO THE MOUNTAINS AND THIS WILL SPREAD OVER INTO THE NORTHEAST PLAINS THIS MORNING. MEANWHILE...COLD FRONT HAS MOVED THROUGH ALL OF NORTHEAST COLORADO WITH SHALLOW N-NE UPSLOPE FLOW DEVELOPING OVER THE PAST FEW HOURS. SURFACE DEWPOINTS HAVE BEEN RISING INTO THE MID 40S AND WE SHOULD START SEEING SOME STRATUS DEVELOPING BETWEEN 09-12Z ACROSS THE FRONT RANGE GIVEN THE ASCENT AND UPSLOPE DEVELOPING. SHORT RANGE MODELS STILL SHOWING A MOISTENING AIRMASS THIS MORNING WITH SHOWERS SPREADING OUT OVER THE PLAINS. CURRENT LIKELY POPS STILL SEEM REASONABLE BUT AMOUNTS STILL LOOK TO BE ON THE LOW SIDE AS THE TROF WILL MOVING MOVING RIGHT ALONG AND NOT A TON OF DEEP MOISTURE DEVELOPING WITH THIS QUICK MOVING SYSTEM. TEMPERATURES MUCH COOLER TODAY WITH READINGS ONLY IN THE 50S AND LOWER 60S OVER THE PLAINS. MAY SEE SOME LIGHT SNOW ACCUMULATIONS IN THE MOUNTAINS AND WITH THE MORE SCATTERED NATURE DON`T SEEM MUCH MORE THAN 2-4 INCHES IN THE HIGHER MOUNTAINS. POSSIBLY A BIT MORE IN THE HEAVIER EMBEDDED CONVECTIVE SNOW SHOWER. BOTH NAM/GFS SEEM A BIT HIGH WITH LIQUID AMOUNTS OVER AN INCH IN MOUNTAINS AND HIGHER EAST SLOPES. THE LOW WILL HAVE MOVED INTO WESTERN KANSAS BY LATE IN THE DAY WITH SUBSIDENCE SPREADING OVER THE PLAINS THIS AFTERNOON. HENCE A DECREASE IN SHOWER ACTIVITY AND ENDING IN MOST LOCALES DURING THE EVENING HOURS. GRADUAL CLEARING OVERNIGHT ACROSS THE ENTIRE AREA. .LONG TERM...NORTHEAST COLORADO UNDER WEST-NORTHWESTERLY FLOW ALOFT WITH THE SHORTWAVE TROUGH CONTINUING ITS EASTWARD PROGRESSION ACROSS THE CENTRAL GREAT PLAINS DURING THE DAY SUNDAY. SHOULD SEE A WARMER DAY WITH A 2C WARMING AT 700 MBS. MODELS ALSO SHOW S-SELY SFC WINDS ON THE PLAINS STEADILY STRENGTHENING DURING THE DAY WHICH AIDS IN TRANSPORTING INCREASINGLY HUMID AIR NORTHWARD UP ALONG THE FRONT RANGE. STEEP LAPSE RATES DUE TO STG DAYTIME HEATING AND THE ARRIVAL OF THIS MOISTURE SHOULD SUPPORT AT LEAST ISOLATED T-STORM DEVELOP OVER AND NEAR THE FRONT RANGE DURING THE AFTERNOON AND EVENING HOURS. STORMS MOVING OUT ACROSS THE PLAINS MAY LINGER WELL INTO THE EVENING WITH THIS MOIST SELY INFLOW. ON MONDAY...FCST AREA BENEATH A STG 500 MB HIGH PRESSURE RIDGE WITH TEMPERATURES ALOFT CONTINUING TO WARM. A BRISK SOUTHERLY LOW- LEVEL FLOW ON THE PLAINS WILL CONTINUE TO ADVECT MOISTURE UP INTO THE AREA. BY AFTERNOON...MODELS SHOW AN 850-700 THETA-E RIDGE AXIS ALIGNED FM COLORADO SPRINGS TO JULESBURG. ALONG THIS AXIS SFC BASED CAPES PROGGED IN THE 1200-2000 KG/J RANGE BY LATE IN THE DAY. HOWEVER STG WARMING ALOFT AND WEAK CIN POSSIBLY ENOUGH TO SUPPRESS CONVECTION. FOR NOW WILL LEAVE OUT MENTION OF T-STORMS ON THE PLAINS...BUT CAN/T RULE THEM OUT ENTIRELY. WHEREAS WILL MENTION AT LEAST A SLIGHT CHANCE OF T-STORMS OVER AND NEAR THE FRONT RANGE FOR LATE IN THE DAY. GOING FOR TEMPERATURES ON MONDAY IN THE LOWER-MID 80S AT LOWER ELEVATIONS WITH UPPER 50S- 70S IN THE HIGH COUNTRY. BY TUESDAY...UPPER RIDGE MOVES EAST OF THE STATE PLACING THE AREA UNDER INCREASING SOUTHWESTERLY FLOW ALOFT. A DRIER MID-LEVEL WITH SUBSIDENCE ON THE SOUTH SIDE OF AN APPROACHING UPPER AIR TROUGH SHOULD RESULT IN PLENTY OF SUNSHINE DURING THE MORNING HOURS. COMBINATION OF UNSEASONABLY WARM TEMPERATURES...LOW HUMIDITY AND AND STEEP LAPSE RATES WILL LIKELY INCREASE THE WILDLAND FIRE DANGER IN MANY AREAS. NOT UNTIL LATE IN THE DAY WHEN THE UPPER TROUGH NEARS WILL SEE CONVECTION...MOST OF WHICH SHOULD BE CONFINED TO THE HIGHER TERRAIN NORTH OF I-70. SHOULD SEE ANOTHER DAY OF VERY WARM TEMPERATURES WITH HIGHS PUSHING THE 90 DEG MARK ON THE PLAINS. BY WEDNESDAY TEMPERATURES TURN COOLER WITH PASSAGE OF THE UPPER TROUGH AND PASSAGE OF A COLD FRONT DURING THE DAY. SHOULD SEE THE CHANCE FOR SHOWERS AND T-STORMS ALSO INCREASE. THE UPPER TROUGH PASSES TO THE EAST OVERNIGHT RESULTING IN A SLIGHT MODERATION IN TEMPERATURE AND A REDUCED CHANCE IN PRECIP. FOR LATER IN THE WEEK...SHOULD SEE STEADY WARMING WITH THE RETURN OF RIDGING. && .AVIATION...CEILINGS LOWERING BY DAYBREAK WITH MAINLY MVFR/ILS APPROACHES THROUGH THIS MORNING WITH RAIN SHOWERS AND THEN IMPROVING TRENDS DURING THE AFTERNOON. SURFACE WINDS SHOULD REMAIN N-NE TODAY BEFORE SHIFTING SE-S BY LATER THIS EVENING AND A RETURN TO DRAINAGE. && .HYDROLOGY...RAINFALL AMOUNTS LOOK TO BE IN THE QUARTER TO HALF INCH RANGE FOR TODAY WITH RAINFALL RATES GENERALLY A TENTH OF AN INCH PER HOUR OR LESS WITH THE SHOWERS. ANY FLOODING POTENTIAL IN THE BURN AREAS SEEM LOW. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ENTREKIN LONG TERM....BAKER AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
347 AM EDT SAT MAY 19 2012 .SHORT RANGE (TODAY-MONDAY)... RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL. THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO -11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING STRAIGHT LINE WINDS AND HAIL. TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND AFTERNOON SEA BREEZES. .LONG RANGE (MONDAY NIGHT-FRIDAY)... THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30 PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER 70S. && .MARINE... A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF PERIODS WITH LOCALLY HIGHER WINDS AND SEAS. && .AVIATION... THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL BE DRY AGAIN. THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS FOR TODAY. && .FIRE WEATHER... SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS. THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE VERY POOR RANGE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 85 71 85 73 / 50 50 30 20 FORT LAUDERDALE 85 72 86 74 / 50 50 30 20 MIAMI 86 73 86 73 / 50 50 30 20 NAPLES 86 70 86 71 / 40 20 40 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 AM CDT SAT MAY 19 2012 .SYNOPSIS... 06Z SFC ANALYSIS HAS THE FRONT WITH LOW PRESSURE CENTERS ALONG IT RUNNING FROM NORTHWEST MINNESOTA INTO NORTHERN COLORADO. A MESO HIGH ASSOCIATED WITH A SMALL MCS WAS ACROSS NEBRASKA WHILE A DRY LINE RAN FROM FROM NEAR KMCK TO KCVS. DEW POINTS WERE IN THE 40S ACROSS THE GREAT LAKES WITH 50S OVER MUCH OF THE MIDWEST. && .SHORT TERM...TODAY AND TONIGHT VERY WARM AND BREEZY CONDITIONS WILL BE SEEN ACROSS THE AREA TODAY. IF THE SAME NEAR 30 DEGREE DIURNAL SWING TAKES PLACE TODAY THEN MAX TEMPS WOULD BE IN THE LOW TO MID 90S. THE OVERALL WAA AND DEPTH OF DEEP MIXING JUST DOES NOT SUPPORT TEMPERATURES THAT WARM. HOWEVER... PERSISTENCE PLUS SEVERAL DEGREES WOULD SUPPORT UPPER 80S TO LOWER 90S FOR MAX TEMPS. DEW POINTS WILL BE ROUGHLY 10 DEGREES WARMER THAN YESTERDAY BUT HUMIDITY LEVELS WILL STILL BE LOW. TONIGHT...THE EVENING HOURS WILL BE DRY. MCS AND LIFT TOOLS INDICATE CONVECTION WILL FIRE LATE THIS AFTERNOON/EVENING IN WESTERN IOWA PROBABLY NOT FAR FROM THE MISSOURI RIVER. THE QUESTION IS WHETHER SAID CONVECTION WILL MAKE IT INTO THE CWFA PRIOR TO SUNRISE. INTERESTINGLY...ALL MODELS WEAKEN THE CONVERGENCE AFTER MIDNIGHT ACROSS THE AREA. MCS...LIFT...AND HEAVY RAIN TOOLS OFFER MIXED SIGNALS ON PRECIPITATION POTENTIAL. WHEN THE LIFT TOOL IS APPLIED TO ALL THE MODELS...A WEAK BUT CONSISTENT SIGNAL EMERGES SUGGESTING THE POSSIBILITY OF CONVECTION ENTERING THE FAR WESTERN CWFA JUST PRIOR TO DAWN. SO...WILL CONFINE ANY PRECIP TO VERY LATE TONIGHT OVER THE WESTERN QUARTER OR SO OF THE CWFA. HOWEVER...THE CONSISTENT WEAKENING OF THE OVERALL CONVERGENCE BY THE MODELS DOES QUESTION THE POTENTIAL FOR ANY PRECIPITATION ENTERING THE CWFA. ..08.. .LONG TERM...SUNDAY THROUGH NEXT FRIDAY SUNDAY THROUGH SUNDAY EVENING CONTINUES TO REPRESENT A FRONTAL PASSAGE...WITH MODEST AT BEST MOISTURE...AND WEAK FORCING. THE TIMING APPEARS TO HAVE SLOWED JUST ENOUGH TO HAVE THE FRONT WITHIN EASTERN IOWA AT 18 TO 00Z...AND THUS A DIURNAL INCREASE IN CONVECTION SHOULD AFFECT OUR CWA UNLESS THE TIMING SPEEDS UP AGAIN. THE 18Z TO 00Z FROPA IS CONSISTENT IN MODEL GUIDANCE OTHER THAN THE NAM...WHICH REMAINS 3 HOURS FASTER. QPF SHOULD BE GENERALLY LIGHT...WITH BENEFICIAL AMOUNTS SPOTTY IN EXCESS OF A QUARTER INCH. ANY STRONG STORMS WILL DEPEND GREATLY ON CAPE...AND AT THIS POINT...WE ARE EXPECTING HIGHS IN THE LOWER TO MID 80S...WITH DEWPOINTS AROUND 60. THIS WILL BE SUFFICIENT FOR THUNDER...BUT DEPENDING ON WARM MID LEVEL TEMPS...WE MAY NOT SEE A LARGE CAPE POOL. BY LATER SUNDAY NIGHT...CAA AND DRY AIR SHOULD SWEEP IN...ENDING ANY RAINFALL THREAT. MONDAY THROUGH TUESDAY...COOLER CANADIAN AIR SHOULD BE OVER THE REGION...WITH HIGHS IN THE LOWER TO MID 70S...AND LOWS IN THE LOWER TO MID 50S. THIS TWO DAY PERIOD REPRESENTS THE COOLEST PORTION OF THE EXTENDED. WEDNESDAY NIGHT THROUGH FRIDAY...THERE REMAIN LARGE DIFFERENCES IN MODEL DATA. THE GFS CONTINUES TO SHIFT THE TROF/RIDGE EAST FAR ENOUGH DURING THIS PERIOD TO WARRANT SHOWERS AND THUNDERSTORMS IN OUR CWA BEGINNING THURSDAY. SHOULD THE GFS BE CORRECT...WITH SOME SUPPORT FROM THE UKMET AS WELL...THIS MAY BE THE BEGINNING OF A 2 TO 4 DAY PERIOD OF ACTIVE STORMS. HOWEVER...CAPPING IS MOST CERTAINLY GOING TO BE AN ISSUE...WITH THE ECMWF...CONSISTENTLY...SHOWING THE ENTIRE PERIOD BEING HOT AND COMPLETELY DRY. WHILE BOTH POSSIBILITIES REMAIN POSSIBLE...IT IS HARD TO IGNORE SUCH A STRONG ECMWF SIGNAL TOWARDS SUNSHINE AND HOT AIR. ERVIN && .AVIATION... VFR WX WILL CONTINUE THROUGH 08Z/20. RADAR PROFILES SUGGEST THE POTENTIAL FOR LLWS THROUGH SUNRISE BUT THE RAP MODEL TRENDS HAVE LOWER WIND SPEEDS IN THE 1-2KFT AGL LAYER. WINDS WILL PICK UP AROUND 15Z/19 AS THE INVERSION BREAKS AND WILL DROP AGAIN AROUND SUNSET. AFT 08Z/20 CONVECTION IN THE FORM OF SHRA/TSRA MAY AFFECT KCID. CONDITIONS SHOULD REMAIN VFR BUT IF TSRA DO AFFECT KCID THERE IS A POTENTIAL FOR MVFR CONDITIONS. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT SAT MAY 19 2012 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 508 AM EDT SAT MAY 19 2012 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE GREAT LAKES DOWNSTREAM OF TROF IN THE ROCKIES. CWA IS IN THE WARM SECTOR E OF SFC-H85 TROF/COLD FNT AND S OF WARM FNT OVER NRN LK SUP/ ADJOINING ONTARIO. WITH DRYNESS SHOWN ON LOCAL 00Z RAOBS /H925 DEWPT DEPRESSIONS ARE 15 TO 25C ON THE MPX/GRB RAOBS AND THE H85 DEWPT DEPRESSION AT GRB WAS 49C/...SKIES ARE MOCLR OVER UPR MI. DESPITE THE CLEAR SKIES/DRY AIR AND LOCAL DECOUPLING... TEMPS ARE WELL ABV NORMAL WITH STEADY SW FLOW AT H925 LIMITING THE OVERALL DIURNAL TEMP DROP. SOME SHRA/TS DID IMPACT MUCH OF MN THIS PAST EVNG DESPITE FAIRLY DRY AIR.AS SHRTWV LIFTED NNEWD WELL E OF THE MAIN TROF TO THE W...BUT THESE ARE TENDING TO WEAKEN AND STAY W OF EVEN LK SUP. MORE WIDESPREAD SHRA/TS ARE LOCATED IN THE PLAINS CLOSER TO H85 COLD FNT. MAIN FCST CONCERNS TDAY ARE FOCUSED ON FIRE WX. FOCUS FOR TNGT THRU SUN SHIFTS TO SHRA/TS CHCS ASSOCIATED WITH SLOWLY APRCHG UPR TROF/ COLD FNT. TDAY...CWA WL REMAIN UNDER WARM SW FLOW AS COLD FNT TO THE W SLIDES EWD THRU MN. ALTHOUGH H85 TEMPS ARE FCST TO AVG ABOUT A DEGREE LOWER THAN YDAY...VERY DEEP MIXING SHOWN ON THE 00Z MPX RAOB SHOULD SUPPORT MAX TEMPS NEARLY SIMILAR TO WHAT OCCURRED ON FRI PER UPSTREAM OBSVD SFC HI TEMPS...WITH SOME PLACES OVER THE W HALF SEEING THE MERCURY REACH 90. GOING FCST SHOWING THESE HIER TEMPS IN THE DOWNSLOPE AREAS FM ONTONAGON TO BARAGA LOOK ON TRACK. AREAS OVER THE E HALF SHOULD SEE SOME MODERATION OFF LK MI. SOME LK MODERATION MAY SLIP A BIT FARTHER W INTO THE CNTRL IF FCST BACKING WINDS TO MORE DUE S DRAGS THE LK MI MODERATION INTO THAT AREA. SEE FIRE WX SECTION BLO FOR A DISCUSSION OF FIRE WX CONCERNS. TNGT...WITH BLDG UPR RDG FCST OVER THE ERN GRT LKS...OPTED TO FOLLOW THE SOMEWHAT SLOWER 12Z ECMWF/00Z CNDN MODELS FOR THE TIMING OF THE COLD FNT...ESPECIALLY SINCE A SHRTWV LIFTING NEWD OUT OF THE ROCKIES WL INDUCE A LOW PRES TO DVLP ON THIS BNDRY OVER THE PLAINS TDAY. THIS LO IS FCST TO MOVE INTO MN BY 12Z SUN. THE 00Z NAM HAS TRENDED IN THIS DIRECTION AS WELL. IN FACT...THE 12Z ECMWF/0Z CNDN MODELS INDICATE THE BULK OF ANY PCPN WL BE ON THE COLD SIDE OF THE FNT AND STAY W OF IWD THRU 12Z. THIS FCST IS REASONABLE CONSIDERING THE DRYNESS OF THE WARM SECTOR AIRMASS AND FCST DEEP LYR QVECTOR CNVGC BEING FOCUSED UNDER THE SHARPER DPVA ASSOCIATED WITH THE SHRTWV ON THE COLD SIDE OF THE FNT IN MN EVEN AS LATE AS 12Z SUN. STEADY SW FLOW IN THE WARM SECTOR SHOULD ONCE AGAIN LIMIT THE DIURNAL FALL OF TEMP...SO MINS WL BE WELL ABV NORMAL AGAIN. SUN...SINCE THE FAVORED 12Z ECMWF/00Z CNDN MODELS SHOW BULK OF DEEP LYR QVECTOR CNVGC SHIFTING NEWD THRU WRN LK SUP TOWARD ONTARIO... SUSPECT THE HIER POPS WL BE OVER THE NW CWA...WITH PCPN TENDING TO DIMINISH AS THE FNT SHIFTS TO THE E INTO THE CENTRAL CWA BY LATE AFTN. HOWEVER...DAYTIME HEATING MAY OFFSET THE LOSS OF BEST DYNAMICS...ESPECIALLY SINCE THE CNDN MODEL SHOWS HIER H85 DWPTS UP TO 12C SURGING NEWD RIGHT ALONG THE FNT. HOWEVER...THIS SOMEWHAT HIER MSTR IS STILL RELATIVELY LO COMPARED TO H85 TEMPS FCST ARND 16C. SO THE LLVLS WL STILL BE RATHER DRY PER THE MODEL FCST SDNGS...LIMITING DESTABILIZATION. OPTED TO GO WITH LIKELY POPS OVER THE NW CWA...DIMINISHING TO CHC FARTHER TO THE E. RAISED FCST HI TEMPS WELL INTO THE 80S OVER THE E AND CNTRL AWAY FM LK MI MODERATION TO ACCOUNT FOR SLOWER ARRIVAL OF COLD FNT. SUN NGT...EXPECT COLD FNT TO PUSH THRU THE REST OF THE CWA ACCOMPANIED BY CHC POPS AS MAIN SHRTWV/SHARPEST DEEP LYR QVECTOR CNVGC EXITS TO THE NE AND ANY HELP FM DIURNAL HEATING WANES. SINCE GUIDANCE HINTS AT THE ARPCH OF A SECOND SHRTWV FM MN...MAINTAINED THE CHC POPS HANGING WELL BACK BEHIND THE COLD FNT AS HINTED AT BY 00Z NAM/12Z ECWMF AND SHOWN IN PREVIOUS FCST DESPITE MID LVL DRYING IN THE WAKE OF THE INITIAL DISTURBANCE. IF THIS TRAILING SHRTWV IS WEAKER...THE DRYING BEHIND THE FIRST STRONGER SHRTWV MAY END THE POPS FASTER THAN FCST AS FCST BY THE 00Z CNDN. THE ARRIVAL OF H85 TEMPS AOB 5C OVER THE W BY 12Z MON WL BRING A RETURN OF MORE SEASONABLE TEMPS. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 508 AM EDT SAT MAY 19 2012 A SLOWLY TRANSITIONING WX PATTERN...WITH MUCH OF THE PERIOD CONTINUING TO BE DOMINATED BY SOUTHERLY WINDS. INITIALLY WE WILL HAVE THE EXITING COLD FRONT TO OUR EAST...AND HIGH PRESSURE PUSHING IN FROM THE CENTRAL AND N PLAINS. AS A RESULT...EXPECT TEMPS TO BE 10 TO 15 DEGREES COOLER THAN SUNDAY. 850MB TEMPS WILL BE 4-5C. WITH THE COOL TEMPS WILL COME DRY AIR...WITH LOWER DEWPOINTS MONDAY AFTERNOON INTO THE MID 30S OVER THE W HALF. WOULD NOT BE COMPLETELY SHOCKED TO SEE VALUES CLOSER TO 30F...WHICH WOULD GIVE RH VALUES NEAR 25 PERCENT. THE SFC HIGH WILL BE DIRECTLY OVERHEAD TUESDAY MORNING...BEFORE SLIDING E. EXPECT THE RETURN OF S WINDS...AND A LITTLE BETTER MOISTURE. WE WILL SEE STRONGER SOUTHERLY WINDS RETURN BRIEFLY WEDNESDAY AFTERNOON. ADJUSTED MAX TEMPS UP OVER THE TRADITIONAL DOWNSLOPE AREAS NEAR LAKE SUPERIOR...WITH 850MB TEMPS RISING TO 11 TO 15C WITH THE COOLEST VALUES EAST. WENT ABOVE CONSENSUS FOR HIGH TEMPS THURSDAY...ONCE AGAIN WITH A MORE SIGNIFICANT INCREASE TO DOWNSLOPE AREAS. 850MB WINDS PEG OUT BETWEEN 45 AND 60KTS...AND TEMPS JUMP UP TO 15-18C. THE 19/00Z GFS IS ONE OF THE COOLEST SOLUTIONS. WILL BE INTERESTING HOW THE END OF THE WORK WEEK PANS OUT...AND IF THE FRONTAL BOUNDARY SETS UP AND STALLS OVER THE W CWA LIKE THE 19/00Z ECMWF...OR BLOWS THROUGH OUR AREA THURSDAY NIGHT BEFORE STALLING OVER LOWER MI FRIDAY INTO SATURDAY. WILL NOT GET TOO FANCY WITH THE FORECAST THAT FAR OUT...AND WILL KEEP THE SLIGHT CHANCE/LOW CHANCE POPS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 135 AM EDT SAT MAY 19 2012 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. EASTERN EDGE OF LLJ CENTERED OVER NE MN WILL CREATE LLWS ON THE ORDER OF 30 TO 35 KTS OVER THE LOWEST 1KFT TONIGHT...WITH THE MOST PROMINENT SHEAR AT IWD. LLWS IS EXPECTED TO SUBSIDE AFTER DAYBREAK SUNDAY AS MIXING IS ESTABLISHED...BUT THIS WILL ALLOW FOR GUSTY SOUTHERLY WINDS AT ALL SITES...ESPECIALLY AT IWD AND SAW. MID-LEVEL CLOUD COVER THICKENS LATE SATURDAY. SHOWERS AND POSSIBLY A THUNDERSTORM COULD BEGIN TO AFFECT IWD BY THE END OF THE PERIOD AS A TROUGH/COLD FRONT APPROACH THE AREA...THOUGH THEY WILL LIKELY REMAIN TO THE WEST UNTIL AFTER 06Z. LLWS ALSO REEMERGES AT SAW AS THE LLJ REDEVELOPS FURTHER EAST THAN TONIGHT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT SAT MAY 19 2012 WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. LOW PRESSURE STRETCHING FROM SOUTHWESTERN QUEBEC TO NEBRASKA WILL SHIFT NORTHEASTWARD...FILLING SLIGHTLY AS IT CROSSES LAKE SUPERIOR SUNDAY INTO SUNDAY EVENING. BEHIND THIS FEATURE...HIGH PRESSURE WILL BUILD ACROSS THE UPPER GREAT LAKES MONDAY AND MONDAY NIGHT. EXPECT THE HIGH TO SLOWLY EXIT NORTHEASTWARD THROUGH MID WEEK...IN RESPONSE TO A STRONGER LOW NEARING FROM SOUTH CENTRAL CANADA THROUGH THE CENTRAL PLAINS. EXPECT THE LOW TO OUR WEST TO MOVE OVER ONTARIO ON THURSDAY...BEFORE EDGING ACROSS LAKE SUPERIOR THURSDAY NIGHT. && .FIRE WEATHER... ISSUED AT 508 AM EDT SAT MAY 19 2012 AFTER AN OVERNGT OF RELATIVELY POOR RH RECOVERY...EXPECT ANOTHER DAY OF AT LEAST NEAR CRITICAL FIRE WX PARAMETERS. MAX TEMPS THIS AFTN WILL BE SIMILAR TO WHAT WAS OBSVD YDAY...BUT DEEPER MIXING SHOWN ESPECIALLY ON THE 00Z MPX RAOB MIGHT TAP INTO LOWER DEWPTS. IN FACT...SFC DEWPTS WERE AS LO AS 35 TO 45 UPSTREAM YDAY AFTN IN WRN WI/SRN MN. BLENDED MIXED DEWPT TOOL VALUES WITH THE PREVIOUS FCST DEWPTS TO COME UP WITH READINGS DIPPING AS LO AS 43 OR SO. WITH WINDS ALOFT TDAY ALSO NEARLY SIMILAR TO YDAY AND DEEP MIXING RELATED TO DAYTIME HEATING... SUSTAINED WINDS AS HI AS 10 TO 20 MPH WITH GUSTS TO 30 MPH AT THE MORE EXPOSED LOCATIONS ARE LIKELY. OPTED TO ISSUE RFW FOR AN ARK FROM IWD/ONTONAGON TO BARAGA/MQT COUNTIES...AREAS THAT SAW THE POOREST RH RECOVERY EARLY THIS MRNG AND WHERE STRONGER WINDS/HIER DAYTIME HI TEMPS ARE MOST LIKELY. WL ISSUE RFD FOR THE OTHER COUNTIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... RED FLAG WARNING FROM 1 PM EDT /NOON CDT/ THIS AFTERNOON TO 8 PM EDT /7 PM CDT/ THIS EVENING FOR MIZ002-004-005-009-084. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...TK MARINE...KF FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
429 AM CDT SAT MAY 19 2012 .DISCUSSION... WATER VAPOR IMAGERY AND RUC H5 ANALYSIS SHOWS A RATHER EXPANSIVE RIDGE IN PLACE THIS MORNING EAST OF THE MS RIVER...WITH A RATHER COMPLEX TROUGH MOVING INTO THE HIGH PLAINS...WITH SEVERAL SHORTWAVES EMBEDDED WITHIN IT. THE TWO PRIMARY ONES ARE CURRENTLY OVER ERN SODAK AND MOVING FROM CO UP INTO SRN NEB. AT THE SFC...A COUPLE OF AREAS OF LOW PRESSURE COULD BE FOUND OVER FAR SW ONTARIO...WITH ANOTHER NEAR THE CO/NEB/KS BORDER. A COLD FRONT IS ANALYZED BETWEEN THESE LOWS ACROSS THE ERN DAKOTAS. FOR THE H5 PATTERN...THE RIDGING NOW MOVING ON TO THE HIGH PLAINS WILL SLOWLY BEAT DOWN THE ERN RIDGE...WITH THE TROUGH CURRENTLY COMING OUT OF CO WORKING ACROSS THE MPX CWA SUN INTO SUN EVENING. FOR MON/TUE...RIDGING WILL BE BUILDING IN ACROSS CENTRAL NOAM AS A SIGNIFICANT TROUGH DIGS INTO THE PAC NW. AS WE HEAD THROUGH THE SECOND HALF OF NEXT WEEK...THIS PATTERN LOOKS BECOME QUITE AMPLIFIED...AS VERY HIGH HEIGHTS SET UP INTO THE GREAT LAKES...WITH A QUASI-STATIONARY DEEP TROUGH TAKING HOLD ACROSS THE NRN ROCKIES...SETTING THE UPPER MIDWEST UP INTO A POTENTIAL ACTIVE PATTERN. AT THE SFC...THE COLD FRONT WILL WORK INTO WRN MN BY THIS AFTERNOON...AND CLEAR THE MPX WI COUNTIES SUN AFTERNOON. THE LOW CENTER CURRENTLY NEAR THE CO/NEB/KS WILL TRACK ACROSS SOUTH CENTRAL MN INTO THE WRN TIP OF THE U.P. OF MICH SAT NIGHT/SUN. HIGH PRESSURE WILL THEN SLIDE ACROSS THE AREA MON/TUE...BEFORE LEE SIDE TROUGHING REESTABLISHES ITSELF OVER THE NRN HIGH PLAINS WED. NEXT FRONT STILL ON TAP TO MOVE INTO MN WED NIGHT...AND WITH UPPER RIDGE AMPLIFYING OVER THE GREAT LAKES THE LATTER HALF OF NEXT WEEK...THIS FRONT STILL LOOKS TO STALL OUT THEN MEANDER AROUND THE UPPER MS VALLEY INTO THE HOLIDAY WEEKEND. THIS MORNING...STRONG WAA OUT AHEAD OF THE ERN SODAK SHORTWAVE HAS RESULTED IN THE DEVELOPMENT OF AN AREA OF TSRA OVER WRN MN...RADAR TRENDS MATCH WELL WITH THE IDEA THE RUC IS SHOWING...WITH THIS WAA AND ASSOCIATED ACTIVITY BASICALLY GOING DUE NORTH INTO NW MN. DO EXPECT CONDITIONS TO BE FAIRLY QUIET THROUGH THE MORNING...WITH THE SODAK SHORTWAVE AND COLD FRONT EXPECTED TO REMAIN WEST OF THE AREA. ONE CAVEAT IS THE LLJ AND STRONG MOISTURE TRANSPORT IN PLACE ACROSS THE WEST. THIS MAY KEEP SCT SHRA/TSRA ACTIVITY GOING THROUGH THE MORNING OUT WEST...BUT DID NOT PLAY THIS IDEA UP TO MUCH IN THE GRIDS. INSTEAD...WAITED UNTIL THE AFTERNOON TO REALLY GET POPS GOING. BY THEN THE COLD FRONT WILL BE WORKING INTO WRN MN AS UPPER ENERGY BEGINS TO WORK IN OVERHEAD. LOOKING AT HIRES REFLECTIVITY FORECASTS...SEEMS TO BE GOOD AGREEMENT WITH STORMS INITIATING NEAR A RWF TO LONG PRAIRIE LINE BETWEEN 20 AND 22Z...WITH ACTIVITY WORKING EAST TOWARD THE I-35 CORRIDOR SHORTLY AFTER 00Z. FORECAST SOUNDINGS AGAIN SHOW NICE INVERTED-V STRUCTURE THIS AFTERNOON...WITH MLCAPE AGAIN PUSHING UP TO AROUND 1500 J/KG. IN ADDITION...UNLIKE YESTERDAY...BULK SHEAR WILL BE IN THE 30-40 KT RANGE...INDICATING SOME BETTER ORGANIZATION IN CONVECTION IS POSSIBLE. GIVEN LESS FAVORABLE CONDITIONS MANAGED A FEW 60-70 MPH WIND GUSTS AND GOLF BALL SIZE HAIL FRIDAY...DO NOT SEE WHY WE DO NOT HAVE A SIMILAR THREAT FOR SEVERE WEATHER TODAY. IF ANYTHING...WOULD SUSPECT THE WIND THREAT IS A BIT HIGHER AS BETTER SHEAR AND FAVORABLE CONDITIONS FOR COLD POOL GENERATION MAY SUPPORT THE DEVELOPMENT OF ORGANIZED LINE SEGMENTS. BESIDE THE PRECIP...SHOULD BE ANOTHER WARM DAY...THOUGH NOT EXPECTING WIDESPREAD 90S LIKE FRIDAY. TWO LIMITING FACTORS FOR HIGHS TODAY WILL BE MORE CLOUD COVER AND ABOUT A 4 DEG C DROP IN H85 TEMPS. WITH THAT SAID...GUIDANCE HAS HAD A PRETTY STRONG COLD BIAS IN THIS HEAT WAVE...SO CONTINUED TO RUN WITH HIGHS A BIT HIGHER THAN WHAT MOST GUIDANCE WOULD SUGGEST. FOR TONIGHT...WITH THE ARRIVAL OF THE UPPER TROUGH AND ATTENDANT SFC LOW...WE CONTINUE TO SEE A STRONG SIGNAL FOR THE FORMATION OF A DEFORMATION BAND OF PRECIP JUST TO THE WEST OF THE SFC LOW TRACK. BLENDED THE ECMWF/GEM/SREF FOR PRECIP TONIGHT...WITH HEAVIEST BAND OF PRECIP EXPECTED TO SETUP BETWEEN THE WRN TWIN CITIES METRO AND MARSHALL/ALEXANDRIA. WITH THE SFC LOW COMING THROUGH...THIS REALLY SLOWS DOWN THE PRECIP...AND CONTINUED TO LEAN TIMING OF POPS ON SUN CLOSE TO THE ECMWF. THE ECMWF ALONG THE NAM/SREF WOULD INDICATE SUNDAY BEING CLOUDY/RAINY FOR MOST OF THE DAY SUNDAY ACROSS MOST OF THE MN MPX AREA...WITH HIGHS LIKELY NOT LEAVING THE LOWER 60S. FURTHER EAST...THE COLD FRONT/LOW SHOULD BE NEAR AN EAU/LADYSMITH LINE BY 18Z...SO SEVERE THREAT CERTAINLY LOOKS BETTER EAST...THOUGH A MARGINAL TREAT FOR SEVERE WEATHER CAN NOT BE RULED OUT IN THE FAR EAST. MON THROUGH WED STILL LOOK DRY AS HIGH PRESSURE SLIDES ACROSS THE AREA. BIGGEST THING TO WATCH WILL BE LOWS MONDAY MORNING. IF HIGHS ONLY TOP OUT AROUND 60 IN CENTRAL MN...WE COULD SEE LOWS MONDAY MORNING MAKE A RUN AT THE UPPER 30S AS HIGH PRESSURES MOVES IN AND SKIES CLEAR OUT. OTHER THAN THAT...ITS OFF TO WAITING FOR THE NEXT FRONT WEDNESDAY NIGHT. THE ONLY SIGNIFICANT CHANGE NOTED IN THE MODELS WITH THIS FRONT IS THE 19.00 ECMWF BASICALLY HALTS ITS EWRD PROGRESSION ACROSS WRN MN...WITH THE RAIN NOT MAKING IT TO ERN AREAS. AT ANY RATE...CONTINUED TO MENTION HIGH CHANCE/LIKELY POPS...ESPECIALLY WEST WED NIGHT. AFTER THAT...THE QUESTION BECOMES WHERE DOES THE FRONT SET UP. WHERE EVER IT DOES SETUP...NORTH OF THE BOUNDARY THROUGH THE WEEKEND IS LOOKING LIKE IT COULD BE A BREEDING GROUND FOR SOME ACTIVE WEATHER...CERTAINLY SOMETHING TO KEEP A CLOSE EYE ON AS WE HEAD INTO THE BUSY HOLIDAY WEEKEND. && .AVIATION.../06Z TAF ISSUANCE/ OVER THE NEXT 48 HOURS...THUNDERSTORM CHANCES WILL BE THE MAIN FORECAST CHALLENGE. ONGOING THUNDERSTORM ACTIVITY WAS ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE THAT HAD MOVE INTO MN LATE FRIDAY AFTERNOON. THE THUNDERSTORMS CONTINUE TO DEVELOP ALONG A MOIST PLUME THAT EXTENDS OVER NORTHERN MISSOURI INTO MINNESOTA. THE MAIN THUNDERSTORM ACTIVITY WILL CONTINUE TO DEVELOP ALONG AND JUST AHEAD OF NEARLY STATIONARY FRONTAL BOUNDARY OVER THE NORTHERN PLAINS. EXPECT THUNDERSTORMS TO WANE DOWN OVERNIGHT OVER CENTRAL MN...AND PERSIST OVER WESTERN MINNESOTA THROUGH SATURDAY MORNING. BASES OF THE THUNDERSTORMS WILL BE AT OR ABOVE 4000 FEET AGL. BY MID AFTERNOON SATURDAY...EXPECT MORE WIDESPREAD THUNDERSTORMS OVER MUCH OF WESTERN MN...AND OVER THE EAST CENTRAL MN AND WESTERN WISCONSIN...MAINLY AFTER MIDNIGHT TOMORROW NIGHT. WEATHER CONDITIONS WILL REMAIN VFR FOR THE MOST PART...EXCEPT IN AND NEAR THE VICINITY OF THUNDERSTORMS. SOUTH-SOUTHEAST WINDS INCREASING TO 20 TO 30 KNOTS OVER EASTERN HALF OF THE FORECAST AREA SATURDAY. WINDS SHIFTING TO THE NORTHWEST OVER WESTERN MN DURING THE AFTERNOON. KMSP...VFR CONDITIONS PREVAILING THROUGH SATURDAY AFTERNOON/EVENING. SCATTERED THUNDERSTORMS DEVELOPING DURING THE EVENING...WITH THUNDERSTORMS BECOMING MORE LIKELY AROUND MIDNIGHT AND OVERNIGHT SATURDAY NIGHT. SOUTH WINDS INCREASING TO 15 TO 25 KNOTS BY MID MORNING SATURDAY. OUTLOOK... SAT NIGHT-SUN...SHRA/TSRA LIKELY WITH BRIEF MVFR/IFR POSSIBLE AS A COLD FRONT PUSHES THROUGH. MON-TUE...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/JVM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1132 PM CDT FRI MAY 18 2012 .DISCUSSION... MOSTLY SUNNY SKIES AND STRONG SOUTHERLY WINDS ACROSS THE UPPER MIDWEST AHEAD OF A SURFACE TROUGH LOCATED OVER THE HIGH PLAINS ALLOWED FOR NEAR RECORD WARMTH THIS AFTERNOON IN MINNESOTA AND WISCONSIN. THE TROUGH OF LOW PRESSURE WILL GRADUALLY SLIDE EASTWARD IN RESPONSE TO THE UPPER LEVEL FORCING...LEADING TO SHOWERS AND THUNDERSTORMS CHANCES FOR THE WEEKEND. THERE WILL BE A BRIEF DRY PERIOD MONDAY AND TUESDAY...WITH ON AND OFF THUNDERSTORM CHANCES RETURNING FOR THE LATTER HALF OF THE PERIOD. TODAY THROUGH SUNDAY... LATEST WATERVAPOR IMAGERY COMBINED WITH 500MB HEIGHTS AND WINDS SHOWED A BROAD LONGWAVE ACROSS THE GREAT BASIN...WITH UPPER LEVEL DIVERGENCE DOWNSTREAM OVER THE HIGH PLAINS. THIS DIVERGENCE CAN BE SEEN IDENTIFIED BY BOTH THE WIDESPREAD CLOUD FIELD AND SURFACE PRESSURE TROUGH OVER THE HIGH PLAINS OF EASTERN MONTANA AND THE WESTERN DAKOTAS. WITHIN THIS FLOW WERE A FEW FEATURES OF INTEREST. THE FIRST OF WHICH IS A SHORTWAVE CROSSING THE MISSOURI RIVER VALLEY INTO WESTERN IOWA. AN ADDITIONAL WAVE IS OFF THE BRITISH COLUMBIA COAST...ALONG WITH A FEW EMBEDDED SHORTAVES IN THE LONGWAVE THROUGH NEAR THE 4 CORNERS REGION. THE FIRST WAVE IS ENOUGH TO SPARK A FEW ISOLATED SHOWERS ACROSS THE SOUTHWESTERN CWA...AS INDICATED BY THE LAST FEW HRRR RUNS...AND CU FIELD. THE MAIN CHANCE FOR PRECIP WILL BE LATER TOMORROW BEGINNING OUT WEST AND SPREADING ACROSS THE THE REGION FOR SATURDAY NIGHT INTO SUNDAY. LARGE SCALE ASCENT ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BEGIN TO OVERTAKE THE REGION...WITH A FEW FOCUSED AREAS OF PRECIP AS 3 DIFFERENT IDENTIFIABLE SHORTWAVES MOVE ACROSS THE REGION. IS LOOKS LIKE THE BEST CHANCE FOR RAIN WILL BE SATURDAY NIGHT INTO SUNDAY MORNING...AND HAVE INCREASED THE POPS AND QPF DURING THIS TIME FRAME. FORECAST SOUNDINGS SHOW SOME DIRECTIONAL SHEAR...BUT OVERALL THE WINDSPEEDS ARE LESS THAN 50KTS. THE SHEAR INCREASES SATURDAY NIGHT AS THE LOW LEVEL JET STRENGTHENS...BUT THE UPPER LEVEL WINDS REMAIN LESS THAN 50KTS. SOUNDINGS ALSO INDICATE 1500 TO 2000 J/KG OF CAPE. SO BOTTOM LINE IS THE POTENTIAL FOR SEVERE WEATHER DOES EXIST...BUT IT SHOULD BE SPORADIC IN NATURE. IT LOOKS LIKE WE SHOULD SEE SOME GOOD SOAKING RAINS WITH MULTIPLE ROUNDS OF PRECIP AS EACH WAVE MOVES THROUGH MONDAY THROUGH FRIDAY....DRY WEATHER IS EXPECTED AS HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR MONDAY AND TUESDAY. ON WEDNESDAY A POWERFUL 120-140KT JET WILL CROSS THE WEST COAST AND MOVE INLAND. AS IT DIGS OVER THE WESTCENTRAL US...IT WILL TAKE ON A NEGATIVE TILT. THIS SETUP WILL DEVELOP A CYCLONE ACROSS THE HIGH PLAINS...AND HAS THE POTENTIAL TO PRODUCE SOME SEVERE WEATHER FOR THE LATTER HALF OF NEXT WEEK OVER THE GREAT PLAINS REGION. IT IS TOO EARLY TO TELL THE EXACT TIMING AND PLACEMENT OF SEVERE STORMS...BUT AS OF NOW CHOSE TO GO WITH A BLEND OF THE GFS...ECMWF...AND PREVIOUS FORECAST...AND HAVE CHANCE POPS THROUGHOUT THE EXTENDED PERIOD. && .AVIATION.../06Z TAF ISSUANCE/ OVER THE NEXT 48 HOURS...THUNDERSTORM CHANCES WILL BE THE MAIN FORECAST CHALLENGE. ONGOING THUNDERSTORM ACTIVITY WAS ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE THAT HAD MOVE INTO MN LATE FRIDAY AFTERNOON. THE THUNDERSTORMS CONTINUE TO DEVELOP ALONG A MOIST PLUME THAT EXTENDS OVER NORTHERN MISSOURI INTO MINNESOTA. THE MAIN THUNDERSTORM ACTIVITY WILL CONTINUE TO DEVELOP ALONG AND JUST AHEAD OF NEARLY STATIONARY FRONTAL BOUNDARY OVER THE NORTHERN PLAINS. EXPECT THUNDERSTORMS TO WANE DOWN OVERNIGHT OVER CENTRAL MN...AND PERSIST OVER WESTERN MINNESOTA THROUGH SATURDAY MORNING. BASES OF THE THUNDERSTORMS WILL BE AT OR ABOVE 4000 FEET AGL. BY MID AFTERNOON SATURDAY...EXPECT MORE WIDESPREAD THUNDERSTORMS OVER MUCH OF WESTERN MN...AND OVER THE EAST CENTRAL MN AND WESTERN WISCONSIN...MAINLY AFTER MIDNIGHT TOMORROW NIGHT. WEATHER CONDITIONS WILL REMAIN VFR FOR THE MOST PART...EXCEPT IN AND NEAR THE VICINITY OF THUNDERSTORMS. SOUTH-SOUTHEAST WINDS INCREASING TO 20 TO 30 KNOTS OVER EASTERN HALF OF THE FORECAST AREA SATURDAY. WINDS SHIFTING TO THE NORTHWEST OVER WESTERN MN DURING THE AFTERNOON. KMSP...VFR CONDITIONS PREVAILING THROUGH SATURDAY AFTERNOON/EVENING. SCATTERED THUNDERSTORMS DEVELOPING DURING THE EVENING...WITH THUNDERSTORMS BECOMING MORE LIKELY AROUND MIDNIGHT AND OVERNIGHT SATURDAY NIGHT. SOUTH WINDS INCREASING TO 15 TO 25 KNOTS BY MID MORNING SATURDAY. OUTLOOK... SAT NIGHT-SUN...SHRA/TSRA LIKELY WITH BRIEF MVFR/IFR POSSIBLE AS A COLD FRONT PUSHES THROUGH. MON-TUE...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1216 AM CDT SAT MAY 19 2012 .AVIATION... COLD FRONT WILL CONTINUE TO MOVE EAST ACROSS WESTERN AND CENTRAL NEBRASKA THROUGH THE EARLY MORNING HOURS. THUNDERSTORMS WILL MOVE OUT OF WESTERN NEBRASKA THROUGH 1909Z. ABUNDANT LOW LEVEL MOISTURE BEHIND THE FRONT WILL BRING AREAS OF PATCHY DRIZZLE WITH MVFR CEILINGS AFTER SUNRISE AND POSSIBLY SOME IFR CEILINGS AT BOTH KLBF AND KVTN TAF SITES. STRONG NORTHWEST WINDS WILL CONTINUE BEHIND THE FRONT THROUGH THE DAY. AS NEXT MID LEVEL WAVE PUSHES THROUGH THIS AFTERNOON CEILINGS TO RISE WITH SHOWERS DEVELOPING. SHOWERS WILL END THROUGH EARLY EVENING WITH WINDS SUBSIDING. && .PREV DISCUSSION... /ISSUED 842 PM CDT FRI MAY 18 2012/ UPDATE... UPDATED WIND FORECAST. WEATHER FORECAST ON TRACK. THUNDERSTORMS NOT PUTTING OUT MUCH IN WAY OF RAIN BUT SOME WIND AND MOSTLY SMALL HAIL. NUMEROUS LIGHTNING STRIKES WITH CLUSTER IN GARDEN GRANT AND ARTHUR COUNTIES. LOOKS TO BE JUST ENOUGH TREAT TO DIMINISH FIRE THREAT. && .PREV DISCUSSION... /ISSUED 842 PM CDT FRI MAY 18 2012/ AVIATION... STRONG STORMS MOVING ACROSS WESTERN NEBRASKA THIS EVENING. HAVE INCLUDED TEMPO GROUP FOR KVTN THROUGH 4Z. NORTHWEST WINDS BUILDING INTO THE NORTHWEST PANHANDLE. FROPA EXPECTED AT KVTN AROUND 1906Z AND KLBF 1911Z. STRATUS AND CEILINGS LOWERING INTO THE IFR CATEGORIES WITH DRIZZLE EXPECTED TO BUILD IN AFTER FROPA AND THEN LIGHT TO MODERATE RAIN DEVELOPING THROUGH THE AFTERNOON WITH CEILINGS LIFTING INTO MVFR. PREV DISCUSSION... /ISSUED 330 PM CDT FRI MAY 18 2012/ DISCUSSION... A POWERFUL UPPER LEVEL DISTURBANCE ACROSS COLO WILL MOVE SLOWLY EAST TONIGHT AND SATURDAY PRODUCING SCATTERED TSTMS...MAINLY ACROSS NORTH AND WEST PARTS OF THE FCST AREA WHICH WILL BE CLOSER TO THE BEST DYNAMICS. SUPER ENSEMBLE FCST QPF SUGGESTS AROUND 1/4 INCH OF RAIN NEAR NORTH PLATE AND CLOSE TO 3/4 OF AN INCH NEAR VALENTINE. FOR THIS EVENING THE THREAT OF HIGH BASED TSTMS CAPABLE OF GUSTY OR PERHAPS ISOLATED DAMAGING DOWNBURSTS WILL CONTINUE AS SFC RH IS OPERATING BELOW 40 PERCENT. ONCE THE COLD FRONT SWEEPS SOUTH LATER TONIGHT THE WIND THREAT SHOULD DIMINISH. THE ECM CONTINUES TO BE SLOWER WITH COLD FRONT HOLDING IT UP SOME SATURDAY AFTERNOON ACROSS THE ERN ZONES. THIS WAS INCORPORATED IN THE TEMP FORECAST FOR HIGHS IN THE 70S EAST...BUT UPPER 50S TO AROUND 60 WEST. THE UPPER LEVEL DISTURBANCE SHOULD CLEAR THE FCST AREA SATURDAY NIGHT WITH STRONG HIGH PRESSURE BUILDING IN SUNDAY FOR NEARLY CLEAR SKIES AND HIGHS IN THE 60S TO AROUND 70S. THE SFC HIGH WILL MOVE OFF EAST QUICKLY MONDAY WITH SOUTHERLY RETURN FLOW DEVELOPING AND A STRONG THERMAL RIDGE DEVELOPING ACROSS THE HIGH PLAINS AND CNTL ROCKIES BY LATE MONDAY AFTERNOON. THIS THERMAL RIDGE SHOULD MIGRATE EAST INTO THE NEB PANHANDLE TUESDAY AFTERNOON. MIX DOWN TOOLS FROM 700 MB SUGGESTS HIGHS IN THE LOWER 90S. FOR NOW 80S WILL OPERATE. ALL MODELS EXCEPT THE SLOWER AND VERY WARM GEM THEN SWEEP A COLD FRONT THROUGH WEDNESDAY LOWERING TEMPS ABOUT 10 DEGREES. THE FRONT WILL THEN LIFT SLOWLY NORTH THROUGH KS AND BECOME STATIONARY ACROSS SWRN NEB FRIDAY. ALL ALONG A DEEP UPPER LEVEL TROF WILL DROP INTO THE WRN U.S. AND WINDS ALOFT WILL BECOME SOUTHWEST AND INCREASE IN SPEED. SFC LOW PRESSURE WILL DEEPEN TO BELOW 990 MB ACROSS WRN KS SUPPORTING WINDY CONDITIONS...SHARP MOISTURE GRADIENTS AND A STRONG CAP...PERHAPS AS STRONG AS 12C ACROSS SRN NEB. GIVEN THE FAST FLOW ALOFT AND FOCUS OF THE SFC LOW...ISOLATED AND LOW-CHC POPS ARE IN PLACE LATE TUESDAY THROUGH THURSDAY. FIRE WEATHER... A FAIRLY SHARP DRYLINE HAS FORMED NEAR WRAY AND HOLYOKE COLO THIS AFTN WHERE RH IS RUNNING 11 TO 15 PERCENT. THE RUC SHOWS THIS DRYLINE PUSHING EAST INTO SWRN NEB LATE THIS AFTERNOON AS THE SFC LOW MOVES EAST TO NEAR BURLINGTON COLO. THE RED FLAG WARNING WILL CONTINUE IN EFFECT THIS EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/EXTENDED...CDC AVIATION...POWER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
158 AM EDT SAT MAY 19 2012 .SYNOPSIS... STALLED LOW PRESSURE WILL CONTINUE TO BRUSH THE COAST...BRINGING RAIN AND A FEW THUNDERSTORMS INTO THE MIDDLE OF NEXT WEEK. LOW PRESSURE WILL FINALLY BEGIN TO MOVE NORTHEAST AND AWAY FROM THE AREA WITH DRIER WEATHER FOR THE END OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM FRIDAY...LATEST HRRR CONSOLIDATES THE BROAD SFC LOWS OFF THE CAROLINA COASTS TO 1 INTENSE CONCENTRIC LOOKING LOW JUST OFFSHORE FROM THE CAROLINA COASTS OVERNIGHT INTO SATURDAY. LATEST NAM ALSO FAVORS THIS SOLUTION. SO WITH EGG ON MY FACE...HAVE UPDATED THE ZONES WITH STRONGER NORTH TO NORTHEAST ACROSS THE FA WITH THE ADDITION OF GUSTS UP TO AND OVER 20 KT ACROSS THE COASTAL COUNTIES. BASED ON SURROUNDING 88DS INCLUDING OURS...THE CURRENT LOCATION OF THE SFC LOW IS ROUGHLY 85 MILES SOUTHEAST OF BALD HEAD ISLAND. LIGHT RAIN WILL CONTINUE TO TRACK WESTWARD AND PLAGUE THE COASTAL COUNTIES...WITH THE MAIN CONVECTION STAYING NEAR THE SFC LOW ITSELF. DO NOT ANTICIPATE ANY ONSHORE MOVEMENT OF THIS CONVECTION. IN ADDITION TO UPPING THE WINDS...HAVE LOWERED TONIGHTS MINS BY ATLEAST A CATEGORY. THIS BASED ON LATEST TEMP AND DEWPOINT TRENDS AND A QUICK LOOK-SEE AT THE 00Z MODEL GUIDANCE. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 245 PM FRIDAY...BROAD UPPER LOW NOW CENTERED DIRECTLY OVER THE COASTAL CAROLINAS WILL BE THE DRIVER FOR THE WEATHER IN THE SHORT TERM. VARIOUS MID-RANGE GUIDANCE IN GOOD ACCORD AS TO THE CHARACTER OF THE UPPER LOWS MOVEMENT...A SLOW SPIRAL OFFSHORE ON SATURDAY...THEN A DRIFT TO THE NORTHWEST AND ONSHORE ON SUNDAY. GUIDANCE A LITTLE LESS CLEAR AS TO THE PRECIPITATION CONSEQUENCES AND SURFACE REFLECTIONS FOR THIS FEATURE...ESPECIALLY ON SATURDAY. NAM IS THE WET SOLUTION WHILE ECMWF AND GFS KEEP THE EASTERN CAROLINAS ON THE DRY SIDE ON SATURDAY. HAVE LEANED MORE TOWARDS THE CONSENSUS DRYER SOLUTION FOR SATURDAY...WITH ISOLATED SHOWERS FOR THE COASTAL COUNTIES AND MINIMAL QPF...YET WITH EXTENSIVE CLOUD COVER. MORE AGREEMENT BETWEEN GUIDANCE AND HIGHER CONFIDENCE THAT SUNDAY WILL BE THE WETTER DAY AS THE UPPER LOW AND ITS SURFACE REFLECTION TRACK BACK NORTHWEST OVER LAND. OMEGA FIELDS SUGGEST WE COULD ALSO SEE THUNDERSTORMS DEVELOP SUNDAY AFTERNOON AND EVENING AS CORE OF UPPER LOW MOVES OVERHEAD. EXTENSIVE CLOUDINESS ON BOTH DAYS AND A STEADY NORTH TO NORTHEASTERLY FLOW THROUGH THE PERIOD WILL HELP KEEP DAYTIME TEMPERATURES BELOW NORMAL OVER THE WEEKEND...WITH HIGHS IN THE LOWER TO MID 70S ALONG THE COAST AND MID TO UPPER 70S INLAND. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 3 PM FRIDAY...MID TO UPPER LOW SITTING DIRECTLY OVERHEAD EARLY MONDAY WILL LIFT OFF TO THE NORTHEAST MON NIGHT NIGHT INTO TUES AS ANOTHER SHORTWAVE TROUGH DIGS DOWN OVER THE SOUTHEAST. THIS TROUGH WILL PUSH A COLD FRONT THROUGH AREA TUES NIGHT INTO WED. DEPENDING ON TIMING OF EXITING LOW...WE SHOULD SEE A PERIOD OF SUBSIDENCE BEFORE NEXT SYSTEM COMES. AT THIS POINT IT LOOKS LIKE TUES MORNING MAY BE DRY WITH A BRIEF PERIOD OF DEEPER NW FLOW AND SUBSIDENCE ON BACK END OF LOW. PCP WATER DROPS FROM 1.8 INCHES DOWN TO JUST BELOW 1.5 INCHES BEFORE INCREASING AGAIN IN CONVECTION AHEAD OF COLD FRONT LATE TUES INTO EARLY WED. ONCE THIS FRONT CLEARS THE COAST ON WEDNESDAY...IT LOOKS LIKE WEAK HIGH PRESSURE WILL SETTLE OVER THE AREA THURS AND FRI WITH ONLY LOCALIZED SEA BREEZE CONVECTION POSSIBLE. DEEP DRY NORTHERLY FLOW ALOFT WILL VEER AROUND THURS THROUGH FRI WITH MOISTURE MAINLY CONFINED TO 5K FT AND BELOW FROM THURS INTO NEXT WEEKEND. WITH CLOUDS AND DEEP LAYER MOISTURE OVER AREA THE FIRST HALF OF THE WEEK...AND H5 HEIGHTS AROUND 575 DEM...EXPECT TEMPS TO REMAIN BELOW NORMAL UNTIL LOW LIFTS OFF AND FRONT PASSES BY ON WED. WARMING TREND WILL BEGIN WED WITH TEMPS REACHING ABOVE NORMAL AS RIDGE BUILDS OVER THE CAROLINAS FRI THROUGH NEXT WEEKEND. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 06Z...EXPECT VFR THROUGH VALID PERIOD...WITH EXCEPTION OF POTENTIAL FOR LOW MVFR CEILINGS EARLY THIS MORNING AT KILM/KMYR/ KCRE. A STALLED AREA OF LOW PRESSURE WILL CONTINUE TO SPIN OFF THE CAROLINA COAST. RAIN WILL CONTINUE TO MOVE ONSHORE...WITH WIND GUSTS NEAR 20 KT FOR THE COASTAL TERMINALS. THE INLAND TERMINALS WILL REMAIN DRY WITH OVC MID LEVEL CLOUDS TENDING TO THIN THROUGH THE DAY. THROUGHOUT THE DAY...MAY SEE SOME BREAKS IN THE CLOUDS...BUT OVERALL EXPECT SCT/BKN MID TO HIGH CLOUDS TO LINGER AS LOW PRESSURE STAYS JUST OFFSHORE. AFTER SUNSET...GUSTS WILL SUBSIDE ALLOWING FOR NORTHEAST FLOW AOB 10 KTS TO PREVAIL. EXTENDED OUTLOOK...MORNING STRATUS POSSIBLE THROUGH SUNDAY...MOSTLY OVER THE NORTHERN HALF OF THE CWA && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 11 PM FRIDAY...STRONG SCA FOR ALL WATERS CONTINUES THROUGH SATURDAY AFTERNOON. HAVE UPPED WINDS ACROSS ALL WATERS BASED ON THE LATEST NAM/HRRR GUIDANCE WHICH ILLUSTRATE A CONSOLIDATED LOW. THE KLTX 88D INDICATES THIS LOW NOW 85 MILES SOUTHEAST OF BALD HEAD ISLAND. THE SFC PRESSURE PATTERN AND GRADIENT WILL YIELD NORTH TO NORTHEAST WINDS 15 TO 25 KT WITH GUSTS UP TO 30 KT INTO SATURDAY AFTERNOON. THE LATEST HRRR WIND OUTPUT NO LONGER LOOKS OVERDONE WITH 30 TO 40 KT SUSTAINED WINDS OFFSHORE AND CLOSER TO THE SFC LOW. CORRESPONDING SEAS WILL RANGE FROM 4 TO 7 FT...UP TO 8 AND 9 FT ACROSS THE OUTER WATERS OFF CAPE FEAR. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 245 PM FRIDAY...A GENERALLY NORTHERLY FLOW WILL PREVAIL THROUGH THE PERIOD AS A TROUGH OF LOW PRESSURE LINGERS EAST OF THE WATERS. LOW PRESSURE CENTERS DEVELOPING WITHIN THIS TROUGH WILL TIGHTEN GRADIENTS ENOUGH TO BUMP WINDS UP INTO THE 15 TO 20 KT RANGE THROUGH DAYTIME SUNDAY. WINDS WILL MODERATE LATER ON SUNDAY AS A LOW PRESSURE SYSTEM MOVES OVERHEAD. SEAS WILL BE HIGHEST EARLIEST IN THE PERIOD...WITH 6 FOOTERS LIKELY OVER THE OUTER FRINGES OF OUR WATERS. WILL KEEP SMALL CRAFT ADVISORY HEADLINES FOR DAYTIME SATURDAY AS A RESULT. OTHERWISE...SEE 3 TO 5 FT SEAS FOR MUCH OF THE SHORT TERM...WITH SEAS SUBSIDING LATE ON SUNDAY AS WINDS MODERATE. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 3 PM FRIDAY...WINDS MAY BE A BIT TRICKY ON MONDAY AS LOW PRESSURE SITS OVERHEAD. MAY RETROGRADE JUST ENOUGH TO THE WEST TO PRODUCE A LIGHT S-SW FLOW. THIS LOW WILL LIFT OFF TO THE NORTHEAST LATE MON INTO EARLY TUES WITH A BRIEF VEERING OF THE WINDS BEFORE NEXT SYSTEM MOVES IN. THE WINDS SHOULD BACK AROUND THROUGH TUES AND INCREASE SLIGHTLY OUT OF THE W-SW AS COLD FRONT APPROACHES FROM THE NW. LOOKS LIKE THIS COLD FRONT WILL NOT MAKE A CLEAN SWEEP AND MAY BECOME WASHED OUT ACROSS THE AREA WITH WEAK GRADIENT FLOW SETTING UP BY THURS. WINDS WILL MOST LIKELY BE DRIVEN MORE BY LAND/SEA BREEZE BY THURS. OVERALL EXPECT WINDS 10 KTS OR LESS THROUGH MOST OF THE PERIOD...EXCEPT UP TO 15 KTS IN TIGHTENED GRADIENT FLOW LATE TUES THROUGH EARLY WED. SEAS WILL RUN 2 TO 3 FT EXCEPT ON TUES WHEN THEY INCREASE UP AROUND 4 FT IN OUTER WATERS TUES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252- 254-256. && $$ NEAR TERM...DCH SHORT TERM...REK LONG TERM...RGZ AVIATION...RJD/SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
145 AM EDT SAT MAY 19 2012 .SYNOPSIS... HIGH PRESSURE WILL EXTEND SOUTHWARD INTO THE CENTRAL CAROLINAS THROUGH THE WEEKEND...WHILE A LOW PRESSURE SYSTEM STALLS OUT AND MEANDERS JUST OFFSHORE THE CAROLINA COAST. && .NEAR TERM /TODAY THROUGH SATURDAY NIGHT/... AS OF 10 PM FRIDAY... TONIGHT: SURFACE HIGH PRESSURE CONTINUES TO BUILD/EXTEND INTO CENTRAL NC FROM THE NORTHEAST THIS EVENING... WHILE A GENERALLY STACK LOW PRESSURE SYSTEM IS LOCATED OFF THE COAST OF THE CAROLINAS. THIS SETUP AS ALLOWED DRIER AIR IN THE LOW LEVELS OF THE ATMOSPHERE TO FILTER INTO THE AREA IN MAINLY NORTH TO NORTHEASTERLY FLOW. MEANWHILE... MAINLY HIGH LEVEL CLOUD COVER IS STREAMING INTO THE AREA ALOFT FROM SHOWERS ANS STORMS THE OFFSHORE LOW PRESSURE SYSTEM. GIVEN THE RATHER DRY AIR CONTINUING TO BUILD INTO THE AREA IN THE LOW LEVELS OF THE ATMOSPHERE EXPECT DRY CONDITIONS FOR MOST IF NOT ALL OF THE CWA. THE ONE EXCEPTION MAY BE FROM A FEW VERY LIGHT SHOWERS SKIRTING SOUTHERN SAMPSON COUNTY THIS EVENING IN ASSOCIATED WITH THE OFFSHORE LOW. HOWEVER... GIVEN THE LATEST RAP SOUNDINGS FOR SOUTHERN SAMPSON COUNTIES STILL INDICATE A FAIRLY DRY SUB-CLOUD LAYER BELOW 750 MB (WITH A DRYING TREND BELOW 750 MB EXPANDING THROUGHOUT THE EVENING) WILL KEEP THE FORECAST DRY FOR THE ENTIRE AREA. THUS THE MAIN FORECAST PROBLEM CONTINUES TO BE THE HIGH LEVEL CLOUD COVER AND THE EFFECTS ON TEMPERATURES. HAVE INCREASED CLOUD COVER FROM THE PREVIOUS FORECAST AND INCREASED LOW A DEGREE OR TWO... GIVEN CURRENT OBSERVATIONAL DATA NAM AND GFS FORECAST SOUNDINGS. THIS YIELDS GENERALLY PARTLY TO MOSTLY CLOUDY SKIES FOR A GOOD PART OF THE NIGHT... WITH PERHAPS SOME MOSTLY CLEAR CONDITIONS ACROSS THE WESTERN/NORTHWESTERN PIEDMONT. THUS... WILL GO WITH LOW TEMPS GENERALLY IN THE LOWER TO MID 50S... WHICH IS NOW GENERALLY IN THE MIDDLE OF THE STATISTICAL GUIDANCE RANGE. SATURDAY AND SATURDAY NIGHT: THE AFOREMENTIONED UPPER LEVEL LOW AND ATTENDANT SURFACE LOW ARE PROGGED TO STALL JUST OFFSHORE THE CAROLINA COAST THROUGH 12Z SUNDAY MORNING. MODEL GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH THE PRECISE EVOLUTION OF THESE FEATURES...THOUGH NEITHER MODEL INDICATES MORE THAN A TRACE OF PRECIP IN THE FAR EAST/SE COASTAL PLAIN THROUGH SUNRISE SUNDAY MORNING. HOWEVER...THIS SYSTEM IS EXPECTED TO BECOME MORE PROGRESSIVE DURING THE DAY SUNDAY...RETROGRADING ONSHORE INTO EASTERN NC...AND IF THE SURFACE/UPPER LEVEL LOW RETROGRADE A BIT SOONER THAN CURRENTLY PROGGED...LIGHT SHOWERS WOULD BE POSSIBLE EAST OF THE I-95 CORRIDOR PRIOR TO SUNRISE SUNDAY MORNING. WITH THE ABOVE IN MIND...WILL KEEP THE FCST DRY ON SATURDAY...AND WILL INDICATE A SLIGHT CHANCE OF SHOWERS OR SPRINKLES IN THE COASTAL PLAIN AFTER MIDNIGHT. THE AIRMASS ACROSS CENTRAL NC WILL VARY FROM VERY DRY IN THE WESTERN PIEDMONT (0.50" PWAT AT GSO) TO MOIST IN THE COASTAL PLAIN (PWAT 1.15" AT RWI) ON SATURDAY. EXPECT SUNNY OR MOSTLY SUNNY SKIES IN THE WEST...AND PARTLY CLOUDY TO MOSTLY CLOUDY SKIES IN THE EAST. EXPECT HIGHS ON SATURDAY TO BE SLIGHTLY WARMER THAN TODAY IN THE WESTERN PIEDMONT (MID/UPPER 70S)...AND SIMILAR OR SLIGHTLY COOLER THAN TODAY IN THE FAR EASTERN COASTAL PLAIN (LOWER 70S). LOWS SAT NIGHT IN THE LOWER/MID 50S. -VINCENT && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 100 PM FRIDAY... THE FORECAST WILL HINGE ON THE EVENTUAL FATE/EVOLUTION OF THE MEANDERING CLOSED UPPER LOW AND ASSOCIATED LOW PRESSURE CENTER OFF THE NORTH CAROLINA COAST. OVERALL...THE GUIDANCE ENVELOPE HAS SHIFTED SLIGHTLY WESTWARD/INLAND FOR SUNDAY AND MONDAY...BUT THERE REMAINS SIGNIFICANT SPREAD WITH THE TIMING AND HOW FAR INLAND THIS SYSTEM WILL RETROGRADE. IF CURRENT TRENDS HOLD UP...EXPECT THICKENING CLOUD COVER WITH INCREASING RAIN CHANCES SUNDAY AFTERNOON/EVENING...AND CONTINUING INTO THE DAY ON MONDAY AS THE EASTERLY ATLANTIC MARITIME FEED WILL ADVECT HIGH PWATS ON THE ORDER 1.5-1.6"(2 SD ABOVE NORMAL)INLAND AS THE CIRCULATION CENTER WOBBLES WESTWARD OVER THE FORECAST AREA. EXPECT THAT WE WILL SEE A DIURNAL ENHANCEMENT IN POPS/CONVECTION... SUNDAY AFTERNOON/EVENING AND AGAIN MONDAY AFTERNOON BEFORE THE LOW BEGINS TO FINALLY TRANSLATE EASTWARD MONDAY EVENING/NIGHT WITH THE APPROACH OF THE NORTHERN STREAM TROUGH FROM THE WEST. THERE REMAINS TOO MUCH UNCERTAINTY AT THIS TIME TO DISCUSS IN DETAIL ABOUT ANY SEVERE/HEAVY RAIN THREAT...BUT WILL NEED TO MONITOR THE NEXT DAY OR TWO GIVEN RECENT HEAVY RAINS ACROSS CENTRAL AND EASTERN NC. FOR THE SAME REASONS...WILL KEEP POPS IN THE SLIGHT TO CHANCE CATEGORIES FOR NOW...WITH HIGHEST POPS IN THE EAST. WITH TIME...BUT IF LATER MODEL RUNS START TO EXHIBIT BETTER CONTINUITY... SUNDAY NIGHT AND INTO MONDAY COULD BE A WET PERIOD WITH LIKELY TO CATEGORICAL POPS. SEASONABLE TEMPERATURES SUNDAY THROUGH MONDAY...HIGHLY DEPENDENT ON THE UPPER LOW AND ASSOCIATED RAIN CHANCES. GIVEN THE WESTWARD TREND WITH THE LOW PRESSURE SYSTEM WILL NUDGE FORECAST HIGHS SUNDAY AND MONDAY DOWN A BIT...HIGHS GENERALLY IN THE MID TO UPPER 70S. LOWS 55 TO 60. -CBL && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 245 PM FRIDAY... THERE ARE SOME PRETTY GLARING DIFFERENCES WITH THE TIMING AND AMPLITUDE OF THE NEXT SHORTWAVE TROUGH AND ATTENDANT SURFACE FRONT MOVING EAST THROUGH THE REGION DURING THE TUESDAY THROUGH WEDNESDAY PERIOD. THE GFS IS UP TO ITS USUAL TRICKS/BIAS... RACING THE OPEN WAVE TROUGH EASTWARD THROUGH THE AREA TUESDAY EVENING/NIGHT...WHILE THE EC IS MORE SLOWER TO ADVANCE THE SYSTEM EASTWARD...DEVELOPING INTO A CLOSED LOW INVOF OF THE OHIO/TN VALLEY BEFORE FINALLY CROSSING THE AREA ON THURSDAY. UNTIL THERE IS BETTER MODEL AGREEMENT WILL BROAD BRUSH SLIGHT TO SMALL CHANCE POPS ACROSS THE AREA TUESDAY-WEDNESDAY WITH DRY CONDITIONS AFTERWORDS. MODERATING TEMPERATURES IN THE LOW-LEVEL SWLY FLOW. HIGHS IN THE LOWER TO MID 80S. LOWS IN THE 60S. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 140 AM SATURDAY... HIGH CLOUDS ARE ABUNDANT OVER CENTRAL NC THIS MORNING AS A WEAK LOW PRESSURE SYSTEM LINGERS OFF THE CAROLINA COAST. HOWEVER... SIGNIFICANTLY DIRER AIR IS POURING IN FROM THE NORTHEAST AND HELPING TO KEEP ANY STRATUS CONFINED TO THE COAST...THOUGH THE STRATUS MAY WORK INLAND AND BE JUST EAST OF KFAY AND KRWI AROUND 12Z. VFR CONDITIONS ARE EXPECTED TO CONTINUE TODAY...WITH A GENERALLY LIGHT NORTHEASTERLY WIND THAT MAY APPROACH 10KT IN THE EAST. AS THE LOW PRESSURE OFFSHORE SLOWLY BEGINS TO STRENGTHEN TONIGHT...LOW LEVEL MOISTURE IS FORECAST TO SURGE FURTHER WESTWARD. BASED ON POOR AGREEMENT AMONG MODELS...THERE IS LOW CONFIDENCE IN LOW CEILINGS REACHING KFAY AND KRWI BY 06Z SUNDAY MORNING...THOUGH THE PROBABILITY OF MVFR AND IFR CEILINGS WILL BE INCREASING THROUGH SUNDAY MORNING. LOOKING AHEAD: THERE WILL BE INCREASING CHANCES FOR SHOWERS AND LOW CEILINGS SUNDAY AS A LOW PRESSURE SYSTEM DRIFTS WESTWARD ONSHORE SOMEWHERE OVER NC/VA. THERE IS QUITE A BIT OF UNCERTAINTY REGARDING WHERE THE LOW WILL TRACK AND EXACTLY WHEN POOR AVIATION CONDITIONS WILL BE MOST WIDESPREAD...BUT CONDITIONS SHOULD GENERALLY BE WORSE OVER A MORE PROLONGED PERIOD OVER EASTERN NC SUNDAY AND MONDAY. ANOTHER LOW PRESSURE SYSTEM IS THEN FORECAST TO MOVE INTO THE AREA FROM THE WEST ON TUESDAY...WITH CONTINUED UNSETTLED CONDITIONS POSSIBLE THROUGH MIDWEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...BSD/VINCENT SHORT TERM...CBL LONG TERM...CBL AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
125 AM EDT SAT MAY 19 2012 .SYNOPSIS... A WARM AND TRANQUIL WEEKEND IS IN STORE FOR THE AREA AS A DEEP LAYERED RIDGE OF HIGH PRESSURE MOVES ACROSS OHIO INTO INTERIOR NEW ENGLAND BY LATER ON SUNDAY. WEAK EASTERLY FLOW AT THE SURFACE WILL HOLD DEEPER MOISTURE AT BAY...BUT HUMIDITIES WILL BE ON THE INCREASE OVER WHAT HAS BEEN EXPERIENCED THE PREVIOUS FEW DAYS. A WEAKENING WEATHER SYSTEM SHIFTING THROUGH THE WESTERN GREAT LAKES SUNDAY NIGHT WILL SLOW AS IT MOVES INTO THE OHIO VALLEY...BRINGING THE NEXT THREAT OF SHOWERS AND THUNDERSTORMS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... DESPITE VERY WEAK NEAR-SURFACE WIND FLOW...MOISTURE IS INCREASING FROM SOUTHEAST TO NORTHWEST ACROSS THE FORECAST AREA AT THIS TIME. WITH THE MOSTLY CALM WINDS AND CLEAR SKIES...SOME FOG SEEMS LIKELY IN PRONE AREAS...AND PATCHY REDUCED VISIBILITIES ARE POSSIBLE ELSEWHERE AS WELL. ADDED SLIGHTLY MORE LOW-ELEVATION FOG THAN THE PREVIOUS FORECAST...AND MADE SOME MINOR ADJUSTMENTS TO MIN TEMPS AS WELL. PREVIOUS DISCUSSION > AMPLE SUNSHINE AGAIN TODAY WITH LOW DEWPOINTS /30S AND 40S/...THANKS TO DEEP LAYERED RIDGE OF HIGH PRESSURE OVER THE AREA. 18.19Z RUC ANALYSIS INDICATED A CLOSED-CONTOUR 580DM ANTICYCLONE OVER NRN INDIANA...ATOP A CLOSED-CONTOUR 576DM CYCLONE JUST OFF THE SOUTH CAROLINA COAST. NOT OVER STRONG/IMPRESSIVE SYSTEMS...BUT THIS REX BLOCK TYPE STRUCTURE WILL CONTINUE TO DOMINATE OUR WEEKEND WEATHER PATTERN...WITH WEAK EASTERLY FLOW OUT OF A SURFACE HIGH PRESSURE SYSTEM IN NEW ENGLAND /RATHER BAGGY PRESSURE GRADIENT/ CONTINUING TO HOLD DEEPER BOUNDARY LAYER MOISTURE /60S DEWPOINTS/ WELL SOUTH AND WEST OF THE AREA. IN THE UPCOMING 12-15 HOURS...EXPECT VERY LITTLE SYNOPTIC SCALE CHANGE AS THE MID-LEVEL HIGH DRIFTS THROUGH NRN OHIO AND STRENGTHENS SLIGHTLY WHILE THE LOW OVER THE WRN ATL ELONGATES SOME BEGINS SPLITTING INTO TWO DISTINCT CYCLONIC CIRCULATION CENTERS...ONE IN ERN GA AND THE OTHER OFF THE NC COAST. VERY WEAK SFC FLOW WILL QUICKLY GO CALM THIS EVENING UNDER RAPIDLY STRENGTHENING INVERSION AND DECOUPLING OF THE SHALLOWING BOUNDARY LAYER. THIS SHOULD FOSTER A RAPID EVENING TEMP DROP WITH CLEAR SKIES. RAN A GENERAL BLEND OF THE PREVIOUS FORECAST AND 12Z ECMWF/GFS/NAM MOS...THOUGH TWEAKED A TOUCH DOWNWARD IN THE COOL SPOTS GIVEN IDEAL RADIATIONAL COOLING REGIME. ALSO FOGGED UP THE OHIO AND ADJACENT RIVER VALLEYS LATER IN THE NIGHT...AS BOUNDARY LAYER MOISTURE FROM KY WILL BE SEEPING NWRD OVERNIGHT AS MINOR SLY COMPONENT TO THE GENERAL EASTERLY FLOW WILL ALLOW AN INCREASE IN LLVL MOISTURE. WOULD NOT BE SURPRISED IS FOG BECOMES A LITTLE MORE WIDESPREAD THAN FORECAST ESP OVER NRN KY/SRN OH/SERN IND. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/... VERY LITTLE CHANGE TO THE PATTERN ALOFT ON SATURDAY...THOUGH THE LOW LEVELS WILL BEGIN TO UNDERGO SOME MOISTURE ADVECTION...ESPECIALLY ACROSS SRN/SWRN FORECAST AREA. 18.12Z WRF/GFS INDICATE LOWEST 1KM SPECIFIC HUMIDITIES DOUBLING IN COMPARISON TO FRIDAY...SO BROUGHT DEWPOINTS UP A BIT IN THE SOUTH/SOUTHWEST...PERHAPS NOT ENOUGH. FEEL 18.12Z NAM-WRF SFC DWPTS ABOUT 10F TOO HIGH AS HAS BEEN A PROBLEM THIS SPRING...SO DISCOUNTING THE RATHER STRONG INSTBY THAT DEVELOPS UNDERNEATH THE MID LEVEL RIDGE SATURDAY AFTERNOON. EVEN SO...ADDITIONAL MOISTURE AND A FAVORABLE LAPSE RATE WILL NO DOUBT YIELD SOME DEEPER CUMULUS ACROSS THE SOUTH/SOUTHWEST...BUT THINK NIL FORCING AND CONTINUED RISING HEIGHTS WILL MITIGATE A NEED FOR A RAIN CHANCE AT THIS TIME. A WARM DAY...AND MOS SHOULD PERFORM WELL IN THIS RATHER PREDICTABLE REGIME...SO AGAIN BLENDED PREVIOUS FORECAST WITH MOST RECENT VALUES. SPOT CHECK OF LOW LEVEL THICKNESS CONSIDERATIONS AND MIXING TO 850-825MB /DESPITE VERY WEAK FLOW/ SUGGESTS WIDESPREAD LOWER TO MIDDLE 80S...VERY MUCH IN LINE WITH THE BLEND. LIKELY A REPEAT SCENARIO SATURDAY NIGHT WITH VALLEY FOG...AND LOWS IN THE 50S. SUNDAY IS A CARBON-COPY OF SATURDAY. DISTINCT CIRCULATION CENTERS ATTENDANT TO THE SOUTHEAST CONUS TROUGH RECOMBINE OVER THE OUTER BANKS OF NC WHILE THE MID LEVEL ANTICYCLONE CONTINUES TO DEEPEN TO 585DM OVER INTERIOR NEW ENGLAND. THIS WILL REINFORCE A LOW LEVEL EASTERLY TRAJECTORY...THUS DON/T EXPECT MUCH /IF ANY/ DEWPOINT RISE ON SUNDAY...AND TEMPERATURES SHOULD HOLD VERY SIMILAR TO SATURDAY/S READINGS. PROBABLY A THICKER CIRRUS SHIELD PER BUFR SOUNDINGS...BUT THAT WOULD BE ABOUT THE EXTENT OF SENSIBLE WEATHER. SUNDAY NIGHT BEGINS TO SEE SOME CHANGE AS A TROUGH OF LOW PRESSURE /DAMPENING OUT AND SLOWING AS IT ENCOUNTERS THE BLOCKY FLOW ALONG THE EAST COAST/ APPROACHES THE GREAT LAKES. HAVE KEPT THE NIGHTTIME DRY AT THIS POINT AS 18.12Z GUIDANCE WAFFLING ON WEAK/MID LEVEL- BASED SHOWERS AND STORM PLACEMENT AS FORCING SLOWLY INCREASES LATER IN THE NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... PERIOD OF DRY WEATHER MAY COME TO AN END MONDAY AS MOISTURE AND INSTABILITY INCREASE AHEAD OF AN UPPER TROUGH. WITH THE ECMWF AND GFS COMING INTO FAIR AGREEMENT...KEPT A CHANCE OF THUNDERSTORMS FOR MONDAY...MAINLY IN WESTERN COUNTIES THAT WILL BE AFFECTED MORE BY SURFACE CONVERGENCE AND COOLER AIR ALOFT. STAYED CLOSE TO ECMWF SOLUTION FOR TUESDAY SINCE IT CONTINUES TO SHOW A CLOSED UPPER LOW FORMING AS OPPOSED TO THE FASTER OPEN WAVE DEPICTED ON THE GFS. AS THE UPPER LOW FORMS NEAR CVG...THERE WILL BE A GOOD CHANCE FOR THUNDERSTORMS UNDER A COOL POOL ALOFT COUPLED WITH DEEP MOISTURE ADVECTION FROM THE SOUTH. THUNDERSTORMS CHANCES WILL DIMINISH ON WEDNESDAY AS THE CLOSED UPPER LOW SLIPS EAST ALLOWING DRIER AND MORE STABLE AIR TO WORK IN. THE DRY CONDITIONS ARE EXPECTED TO CONTINUE ON THURSDAY AND FRIDAY WHEN RIDGING ALOFT IS FORECAST TO MOVE BACK IN. HIGH TEMPERATURES WILL BE MAINLY IN THE 80S MONDAY ON THE EAST SIDE OF THE UPPER TROUGH. COOLER READINGS IN THE 70S ARE FORECAST AS THE CLOSED LOW MAKES ITS WAY ACROSS THE AREA WITH ASSOCIATED CLOUD COVER AND COLD ADVECTION. LOOK FOR A REBOUND TO THE 80S BY FRIDAY AS SUNSHINE AND WARM ADVECTION RETURN. && .AVIATION /05Z SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE WILL KEEP DRY CONDITIONS ACROSS THE TAF SITES THROUGH THE TAF PERIOD. VFR CONDITIONS WILL START OUT THE TAF PERIOD HOWEVER SOME FOG WILL BE POSSIBLE AT KLUK...KCVG...AND KILN OVERNIGHT. VFR CONDITIONS WILL RETURN TO THE TAF SITES DURING THE DAY ON SATURDAY. CU WILL DEVELOP ACROSS THE AREA DURING MAINLY THE AFTERNOON HOURS. WINDS WILL BE LESS THAN 10 KNOTS. OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BINAU NEAR TERM...BINAU/HATZOS SHORT TERM...BINAU LONG TERM...CONIGLIO AVIATION...NOVAK
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1125 PM CDT FRI MAY 18 2012 .AVIATION... CONCERNS REMAIN TRAJECTORY OF MVFR STRATUS OVERNIGHT. HAVE CONTINUED WITH THE RUC OPS/BAK40 SOUNDINGS AND NAM12 BOUNDARY LAYER RH/BUFR SOUNDINGS WITH CIGS REMAINING JUST SOUTH THROUGH WEST OF THE METROPLEX...THOUGH SCATTERED STRATO-CU MAY BE AROUND RIGHT AFTER SUNRISE SATURDAY MORNING. FOR WACO...MAINTAINED A TREND OF MVFR CIGS BETWEEN 11Z AND 15Z...THEN VFR AFTERWARD. CONFIDENCE ON STRATUS TRAJECTORY IS NOT HIGH WITH LITTLE OR NO DEVELOPMENT AS OF 05Z UPSTREAM ALONG THE TX COASTAL BEND/LOWER TX COAST/OR NORTHERN MEXICO YET. OTHERWISE...SSE WINDS AROUND 10 KTS...WILL BECOME SLY NEAR 15 KTS BY LATE MORNING SATURDAY WITH GUSTS TO OR IN EXCESS OF 25 KTS POSSIBLE WITH VFR CONDITIONS. LOOK FOR GUSTS TO SETTLE DOWN BY 00Z SUNDAY AS BOUNDARY LAYER SEMI DECOUPLES. 05/ && .UPDATE... GRIDS IN EXCELLENT SHAPE. NO UPDATE NEEDED. 25 && .PREV DISCUSSION... /ISSUED 326 PM CDT FRI MAY 18 2012/ LOW LEVEL WARM AIR ADVECTION WILL CONTINUE ACROSS THE REGION TONIGHT THROUGH SUNDAY AS SURFACE LOW PRESSURE MOVES EASTWARD FROM THE HIGH PLAINS. A RELATIVELY TIGHT PRESSURE GRADIENT WILL RESULT IN BREEZY CONDITIONS THIS EVENING AND AGAIN ON SATURDAY. AS THE SURFACE LOW MOVES EAST...SURFACE HIGH PRESSURE WILL BUILD SOUTHWARD AND A COLD FRONT WILL APPROACH THE RED RIVER SUNDAY MORNING. A FEW SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT...WITH THE BEST CHANCE OF STORMS NORTH OF THE RED RIVER. THE FRONT SHOULD STALL DURING THE DAYTIME HOURS DUE TO VIGOROUS MIXING ALONG THE LEADING EDGE...BUT WILL BEGIN TO MOVE SOUTH AGAIN SUNDAY NIGHT/MONDAY. THE BEST PUSH BEHIND THE FRONT WILL BE EAST OF THE REGION. THEREFORE...THE FRONT WILL MOST LIKELY STALL ACROSS THE NORTHERN PORTIONS OF NORTH TEXAS MONDAY AFTERNOON. THE ATMOSPHERE WILL BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND NORTH OF THE FRONT. SEVERE STORMS ARE UNLIKELY DUE TO A WEAK SHEAR PROFILE. THE COLD FRONT WILL LIFT QUICKLY NORTH OF THE REGION MONDAY NIGHT/TUESDAY AS THE UPPER PATTERN BECOMES MORE ZONAL AND RESULTS IN A THE DEVELOPMENT OF A LEE TROUGH. THIS PATTERN WILL KEEP NORTH TEXAS WARM AND HUMID NEXT WEEK WITH HIGHS MAINLY IN THE UPPER 80S AND LOW 90S AND LOWS GENERALLY IN THE 60S. 79 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 65 87 65 86 65 / 0 5 5 10 10 WACO, TX 65 87 65 87 66 / 0 5 5 5 10 PARIS, TX 62 85 64 86 66 / 0 5 5 10 10 DENTON, TX 63 87 64 85 64 / 0 5 5 10 10 MCKINNEY, TX 61 87 64 86 65 / 0 5 5 10 10 DALLAS, TX 64 87 64 88 65 / 0 5 5 10 10 TERRELL, TX 63 88 63 86 64 / 0 5 5 10 10 CORSICANA, TX 64 88 65 87 67 / 0 5 5 5 10 TEMPLE, TX 64 86 64 86 65 / 0 5 5 5 10 MINERAL WELLS, TX 63 89 65 86 63 / 0 5 5 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
243 AM CDT SAT MAY 19 2012 .SHORT TERM...TODAY THROUGH MONDAY NIGHT 243 AM CDT SAT MAY 19 2012 THE MAIN FOCUS THROUGH THE WEEKEND AND EARLY NEXT WEEK IS WITH THE SHOWER/THUNDERSTORM CHANCES TONIGHT INTO SUNDAY ALONG WITH TEMPERATURES AND WINDS FOR TODAY. AN ELONGATED TROUGH OF SURFACE LOW PRESSURE CONTINUES TO DRIFT EAST ACROSS THE CENTRAL PLAINS WITH MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY IN THE WARM SECTOR OF THIS SYSTEM. THE MAIN LOW IS GETTING ORGANIZED ACROSS EASTERN COLORADO/SOUTHWEST NEBRASKA WHICH IS AHEAD OF A DIGGING MID LEVEL TROUGH STILL OUT IN THE ROCKIES. IN THE NEAR TERM...JUST DEALING WITH SOME HIGH LEVEL CLOUD COVER AND A DECOUPLED ATMOSPHERE. STORMS IN CENTRAL TO NORTHERN MINNESOTA WILL CONTINUE TO LIFT TO THE NORTH AHEAD OF A MID LEVEL SHORTWAVE TROF WHICH WILL TAKE A SIMILAR PATH. THE SOUTHERN EXTENT OF THIS TROUGH WAS VISIBLE ACROSS IOWA VIA IR SATELLITE EARLIER...BUT HAS SINCE DISSIPATED. THREE MAIN FORECAST ISSUES FOR TODAY INCLUDE HOW WARM TEMPERATURES WILL GET...HOW STRONG WILL THE WINDS BECOME...AND WHEN WILL CONVECTION MOVE INTO THE REGION. TEMPERATURE-WISE...THE 19.00Z NAM/GFS/ECMWF/GEM DO NOT SHOW MUCH IN THE WAY OF THE AIR MASS MODERATING ACROSS THE REGION TODAY WITH 850MB TEMPERATURES LINGERING AROUND +16C. YESTERDAY...THESE 850MB TEMPERATURES WERE A BIT HIGHER IN WESTERN MINNESOTA AND IOWA AT ABOUT +20C TO +22C. WITH FULL MIXING IT BROUGHT SURFACE TEMPERATURES INTO THE MID 90S WHILE DEW POINTS ACTUALLY HELD ON INTO THE LOW 50S. WITH A SIMILAR DAY OF FULL MIXING LOCALLY...EXPECT THAT TEMPERATURES SHOULD BE PRETTY CLOSE TO WHERE WE ENDED UP TODAY WITH MOST LOCATIONS IN THE UPPER 80S AND SOME SPOTS GETTING INTO THE 90S. AS FOR THE WINDS...A TIGHT SURFACE PRESSURE GRADIENT WILL REMAIN IN PLACE THROUGH THIS AFTERNOON DUE TO THE DEEPENING SURFACE LOW IN THE SOUTHERN PLAINS AND RIDGE OFF TO THE EAST. 19.00Z NAM BUFKIT SOUNDINGS FROM RST SHOW MIXING FROM THE SURFACE ON UP TO AROUND 800MB WITH WINDS OF ABOUT 40KTS AT THE BASE OF THE INVERSION AROUND 800MB. MOMENTUM TRANSFER SHOWS THAT THE GUSTS SHOULD BE AROUND 30-35KTS WITH LESSER AMOUNTS AS YOU MOVE INTO THE LOWER TERRAIN TO THE EAST. CONSIDERED A WIND ADVISORY FOR PORTIONS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA FOR TODAY...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO DO SO GIVEN THAT THE ADVISORY CRITERIA GUSTS WOULD BE FAIRLY LOCALIZED AND NOT WIDESPREAD/LONG LASTING. PRECIPITATION CHANCES WILL BE ON THE INCREASE AS THE TROUGH/COLD FRONT INCH EASTWARD THIS EVENING AND OVERNIGHT ACROSS EASTERN MINNESOTA...CENTRAL IOWA AND NORTHWEST WISCONSIN. MUCH OF THE FOCUS FOR LIFT WILL COME AS A MID LEVEL TROUGH TRACKS NORTHEAST THROUGH THE SOUTHWESTERLY FLOW. THE 19.00Z NAM/GFS/GEM SHOW THIS MAIN MID LEVEL TROUGH LIFTING NORTHEAST ALONG THE BOUNDARY EARLY SUNDAY MORNING WITH THE SURFACE COLD FRONT MOVING THROUGH IN THE AFTERNOON. THERE IS SOME CONCERN FOR SEVERE WEATHER ON SUNDAY DUE TO A MID LEVEL JET STREAK MOVING THROUGH WITH THE TROUGH AND BUILDING INSTABILITY AHEAD OF THE SURFACE COLD FRONT/LOW. THE TIMING OF THE FRONT AND/OR PRE-FRONTAL SURFACE TROUGH IS IDEAL FOR MAXIMIZING PEAK HEATING...BUT IT APPEARS THAT THE BETTER DEEP WIND SHEAR COMES THROUGH IN THE MORNING AS THE TROUGH MOVES THROUGH WITH THE 40-50KT JET STREAK NORTH OF LAKE SUPERIOR BY AFTERNOON. IF THE SOUTHERN PORTION OF THE MID LEVEL JET STREAK CAN LINGER INTO THE AFTERNOON...IT MAY PROVIDE SOME BETTER 0-6KM SHEAR TO WORK WITH SOME SURFACE BASED INSTABILITY OF 1000-2000J/KG TO PRODUCE SOME ORGANIZED CONVECTION. THESE STORMS/SHOWERS SHOULD EXIT THE REGION SUNDAY NIGHT WITH HIGH PRESSURE AND COOLER AIR DROPPING DOWN BEHIND THE SYSTEM. .LONG TERM...TUESDAY THROUGH FRIDAY 243 AM CDT SAT MAY 19 2012 QUIET START TO THE EXTENDED PERIOD AS A RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION OVER THE MIDDLE OF THE WEEK. THE NEXT FEATURE TO POSSIBLY BRING SOME PRECIPITATION TO THE REGION COMES IN ON WEDNESDAY AFTERNOON IS A COLD FRONT THAT WILL DROP INTO MINNESOTA. SOME FAIRLY SIGNIFICANT DIFFERENCES CROP UP BETWEEN THE 19.00Z GFS/ECMWF/GEM WITH THIS FRONT AND HOW MUCH PROGRESS IT MAKES TO THE EAST GOING INTO THE LATER PORTION OF THE WEEK. THE GFS HAS BEEN PRETTY CONSISTENT WITH SWINGING THE COLD FRONT THROUGH THE REGION AND THEN SETTING IT UP TO THE SOUTH WITH COOL AIR MOVING IN BEHIND IT. MEANWHILE...THE ECMWF HAS BEEN BOUNCING BACK AND FORTH WITH WHETHER THE FRONT EVEN MAKES IT INTO THE REGION ON THURSDAY. OVER THE PAST TWO DAYS...THE 12Z RUNS HAVE BEEN TAKING THE FRONT FURTHER EAST AND BRINGING PRECIPITATION IN WHILE THE 00Z RUNS HAVE KEPT US MAINLY DRY. THE GEM DOES SOMETHING SIMILAR TO THE 00Z ECMWF RUNS WITH KEEPING THE FRONT OFF TO THE WEST AS WELL. WHILE THE 19.00Z GFS APPEARS TO BE AN OUTLIER AT THIS POINT...CAN NOT RULE OUT THE POSSIBILITY OF CONVECTION GETTING INTO THE REGION AND HAVE LEFT SOME CHANCES OUT IN THE EXTENDED PERIOD THOUGH CONFIDENCE IS NOT VERY HIGH WITH THEM. THE MOST NOTEWORTHY FEATURE IN THE EXTENDED PERIOD IS WITH THE HEAT WAVE THAT THE 19.00Z ECMWF IS FORECASTING FROM THURSDAY ONWARD INTO MEMORIAL DAY WEEKEND AS THE FRONT STALLS AND IS FORCED UP TO THE NORTH AS SOUTHERLY LOW LEVEL FLOW BRINGS WARM AIR BACK INTO THE REGION. THE 19.00Z ECMWF IS FORECASTING HIGH TEMPERATURES OF 85-95F FROM THURSDAY THROUGH MONDAY WHILE THE 19.00Z GFS REMAINS MUCH COOLER. AS PREVIOUSLY MENTIONED...CONFIDENCE IS NOT HIGH WITH WHAT MODEL IS THE TREND SETTER...BUT IF THE ECMWF IS THE TREND THEN WE ARE WAY UNDER DOING TEMPERATURES GOING INTO NEXT WEEKEND. && .AVIATION...THROUGH 06Z SUNDAY 1145 PM CDT FRI MAY 18 2012 SOUTHERLY FLOW WILL CONTINUE AT THE TAF SITES THROUGH THE PERIOD. VFR CONDITIONS ARE EXPECTED THOUGH 06Z SATURDAY. WINDS HAVE DECOUPLED AT KLSE WITH SURFACE WINDS AROUND 10 KNOTS. KARX VAD WIND PROFILER SHOWS 2000 FOOT WINDS AT 40 KNOTS AND BOTH THE 19.02Z RAP AND 19.00Z NAM BUFKIT SOUNDINGS SHOWING 35 TO 40 KNOT WINDS CONTINUING JUST OFF THE SURFACE. THUS DID INCLUDE LLWS AT THE KLSE SITE THROUGH 14Z. LOW LEVEL WINDS AT KRST WILL BE MARGINAL FOR LLWS AND WILL NOT INCLUDE. WINDS WILL PICK UP ONCE AGAIN SATURDAY WITH SOME GUSTS TO 30 KNOTS AT KRST AND NEAR 25 KNOTS AT KLSE. A COLD FRONT WILL THEN MOVE INTO WESTERN MINNESOTA DURING THE AFTERNOON AND EVENING HOURS. DID MENTION VCSH AT KRST AFTER 01Z AS FRONT APPROACHES. && .ARX WATCHES/WARNINGS/ADVISORIES... 243 AM CDT SAT MAY 19 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 PM CDT FRI MAY 18 2012 .SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT 343 PM CDT FRI MAY 18 2012 AT 3 PM...A TIGHT SURFACE PRESSURE GRADIENT HAS DEVELOPED BETWEEN A HIGH PRESSURE SYSTEM OVER NEW ENGLAND AND A LOW PRESSURE SYSTEM OVER SOUTH DAKOTA. THIS GRADIENT WAS PRODUCING SUSTAINED WINDS IN THE 15 TO 25 MPH RANGE AND WIND GUSTS AROUND 35 MPH. THE HIGHEST WIND GUSTS WERE 37 MPH AT THE ROCHESTER ASOS AND NEAR DEXTER MINNESOTA. THE COMBINATION OF SOUTHERLY WINDS AND ABUNDANT SUNSHINE HAS ALLOWED TEMPERATURES TO CLIMB TO AROUND 90 ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...AND FROM THE MID TO LOWER 90S ACROSS WESTERN WISCONSIN. THIS MAKES IT THE WARMEST DAY OF THIS YEAR IN MOST LOCATIONS. SO FAR THIS AFTERNOON...THE WARMEST TEMPERATURE REPORTED WAS 94 DEGREES FROM EYOTA /MINNESOTA DOT/. FOR TONIGHT...THE 18.12Z MODELS ARE IN VERY GOOD AGREEMENT THAT A POSITIVELY TILTED SHORT WAVE TROUGH WILL MOVE NORTHEAST THROUGH THE REGION. BUFKIT SOUNDINGS SHOW THAT THE AIR MASS BELOW 600 MB WILL REMAIN RATHER DRY. AS A RESULT...ONLY EXPECTING A SCATTERED TO OCCASIONALLY BROKEN DECK OF MID AND HIGH CLOUDS TO MOVE THROUGH THE REGION. THE GREATEST PERCENTAGE OF THESE CLOUDS WILL WEST OF THE MISSISSIPPI RIVER. ON SATURDAY...THE MAXIMUM TEMPERATURE FORECAST IS RATHER TRICKY. THIS IS DUE TO THE UNCERTAINTY ON HOW WARM THE TEMPERATURES WILL BE ALOFT /NAM HAS THE SAME TEMPERATURES AS TODAY AND THE GFS IS 2C COOLER/ AND MORE AFTERNOON CLOUDS ACROSS THE REGION. DUE TO THE LATTER...TRENDED THE FORECAST A COUPLE OF DEGREES COOLER. THE GFS DOES GENERATE PRECIPITATION NORTH OF THE INTERSTATE 94 CORRIDOR ON SATURDAY AFTERNOON. THIS IS DUE TO A STRONG PV ANOMALY MOVING NORTHEAST THROUGH THE REGION. MEANWHILE THE NAM/ECMWF/GEM HAVE A MUCH WEAKER PV ANOMALY. SINCE THE GFS IS TYPICALLY TO ROBUST WITH THESE ANOMALIES...SO OPTED TO KEEP THE FORECAST DRY. ANOTHER FORECAST ISSUE ON SATURDAY AFTERNOON WILL BE THE DEW POINTS. ALL OF THE MODELS ARE SHOWING THAT THE DEW POINTS WILL CLIMB INTO THE LOWER 60S. THIS LOOKS TO BE TOO HIGH WHEN ONE TAKES IN ACCOUNT THE DRY AIR ALOFT. THE DEW POINT MIX DOWN TOOL SUGGESTS THAT THE DEW POINTS WILL BE MORE IN THE LOWER AND MID 50S. THIS SEEMS MUCH MORE REALISTIC...THUS...WENT AT LEAST 5 TO 8F LOWER THAN THE MOS VALUES. FROM SATURDAY NIGHT INTO SUNDAY...THE MODELS CONTINUE TO STRUGGLE WITH THE TIMING OF THE COLD FRONT THROUGH THE REGION. THE GFS CONTINUES TO THE FASTEST...AND IT HAS THE FRONT THROUGH THE ENTIRE AREA BY EARLY AFTERNOON. MEANWHILE THE OTHER MODELS SUGGEST THAT THIS WILL NOT OCCUR UNTIL SUNDAY EVENING. THE MAIN DIFFERENCE IS HOW FAST THEY MOVE THE POSITIVELY TILTED SHORTWAVE TROUGH THE REGION. WITH THE GFS BEING FASTER WITH THIS FEATURE...IT MAKES SENSE THAT ITS FRONT WOULD MOVE THROUGH THE REGION FASTER. DUE TO THIS WENT WITH MORE OF BLEND FOR THE WINDS...PRECIPITATION CHANCES...AND TEMPERATURES. WITH ALL OF THE MODELS HINTING THAT THE BEST MOISTURE TRANSPORT WOULD BE MAINLY NORTH AND NORTHWEST OF THE FORECAST AREA...AS A RESULT TRENDED THE HIGHEST PRECIPITATION CHANCES FOR THESE AREAS. WHILE ML CAPES CLIMB INTO THE 1500 TO 2500 J/KG...THE 0-6 KM BULK SHEAR IS LESS THAN 30 KNOTS...SO STILL NOT THINKING THAT THERE WILL ANY SEVERE WEATHER FROM ANY OF THESE STORMS. .LONG TERM...MONDAY THROUGH FRIDAY 343 PM CDT FRI MAY 18 2012 THE 18.12Z MODELS ARE STARTING TO BECOME MORE IN AGREEMENT. THEY SHOW THAT A COLD FRONT WILL SAG SOUTHWARD INTO THE AREA ON WEDNESDAY NIGHT AND THEN LINGER ACROSS THE AREA THROUGH FRIDAY MORNING...AND THEN MOVE NORTH AS A WARM FRONT ON FRIDAY AFTERNOON AND NIGHT. THE LATTER IS ASSOCIATED WITH A RIDGE BUILDING ACROSS THE EASTERN UNITED STATES. SINCE THE LATTER HAS BEEN VERY CONSISTENT IN THE ECMWF...THERE WAS ENOUGH CONFIDENCE TO RAISE THE TEMPERATURES A COUPLE OF DEGREES ABOVE THE CONSALL FOR LATE NEXT WEEK. && .AVIATION...THROUGH 06Z SUNDAY 1145 PM CDT FRI MAY 18 2012 SOUTHERLY FLOW WILL CONTINUE AT THE TAF SITES THROUGH THE PERIOD. VFR CONDITIONS ARE EXPECTED THOUGH 06Z SATURDAY. WINDS HAVE DECOUPLED AT KLSE WITH SURFACE WINDS AROUND 10 KNOTS. KARX VAD WIND PROFILER SHOWS 2000 FOOT WINDS AT 40 KNOTS AND BOTH THE 19.02Z RAP AND 19.00Z NAM BUFKIT SOUNDINGS SHOWING 35 TO 40 KNOT WINDS CONTINUING JUST OFF THE SURFACE. THUS DID INCLUDE LLWS AT THE KLSE SITE THROUGH 14Z. LOW LEVEL WINDS AT KRST WILL BE MARGINAL FOR LLWS AND WILL NOT INCLUDE. WINDS WILL PICK UP ONCE AGAIN SATURDAY WITH SOME GUSTS TO 30 KNOTS AT KRST AND NEAR 25 KNOTS AT KLSE. A COLD FRONT WILL THEN MOVE INTO WESTERN MINNESOTA DURING THE AFTERNOON AND EVENING HOURS. DID MENTION VCSH AT KRST AFTER 01Z AS FRONT APPROACHES. && .ARX WATCHES/WARNINGS/ADVISORIES... 253 PM CDT FRI MAY 18 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MIAMI FL
1015 AM EDT SAT MAY 19 2012 .UPDATE...UPDATED FORECAST PACKAGE TO MENTION POSSIBLE STRONG TO SEVERE STORMS THIS AFTERNOON. 12Z SOUNDING PARAMETERS ALMOST IDENTICAL TO FRIDAY`S VALUES. PW=1.72 INCHES, 500 MB TEMP AROUND -10C TO -11C AND THE LIKELIHOOD OF WET MICROBURSTS AND LARGE HAIL. 850 MB ANALYSIS ALSO SHOWS A WEAK TROUGH MOVING SLOWLY EASTWARD ACROSS SOUTH FLORIDA. THIS COMBINED WITH PLENTY OF HEATING AND LEFT-OVER OUTFLOW BOUNDARIES FROM YESTERDAY`S CONVECTIVE ACTIVITY WILL LEAD TO THUNDERSTORMS DEVELOPING JUST ABOUT ANYWHERE IN S. FLORIDA. HOWEVER, WESTERLY MID/UPPER LEVEL FLOW MAY STEER ANY STORM EASTWARD TOWARD THE EASTERN INTERIOR AND EASTERN METRO AREAS. .AVIATION... THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 16Z TODAY...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. CONVECTION IS EXPECTED ACROSS THE PENINSULA TODAY...WITH VCSH ASSIGNED ALL TERMINALS THROUGH 15Z AND VCTS ASSIGNED ALL TERMINALS AT 16Z. MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS THROUGH 15Z AND STARTING AT 16Z PERIODS OF SUB-VFR CONDITIONS AND BRIEF PERIODS OF IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF SHOWERS AND/OR THUNDERSTORMS. 60 && .PREV DISCUSSION... /ISSUED 347 AM EDT SAT MAY 19 2012/ SHORT RANGE (TODAY-MONDAY)... RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL. THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO -11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING STRAIGHT LINE WINDS AND HAIL. TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND AFTERNOON SEA BREEZES. LONG RANGE (MONDAY NIGHT-FRIDAY)... THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30 PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER 70S. MARINE... A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF PERIODS WITH LOCALLY HIGHER WINDS AND SEAS. AVIATION... THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL BE DRY AGAIN. THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS FOR TODAY. FIRE WEATHER... SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS. THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE VERY POOR RANGE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 85 71 85 73 / 50 40 30 20 FORT LAUDERDALE 85 72 86 74 / 50 40 30 20 MIAMI 86 73 86 73 / 50 40 30 20 NAPLES 86 70 86 71 / 40 20 40 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...47/RGH AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
730 AM EDT SAT MAY 19 2012 .AVIATION... THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 16Z TODAY...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. CONVECTION IS EXPECTED ACROSS THE PENINSULA TODAY...WITH VCSH ASSIGNED ALL TERMINALS THROUGH 15Z AND VCTS ASSIGNED ALL TERMINALS AT 16Z. MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS THROUGH 15Z AND STARTING AT 16Z PERIODS OF SUB-VFR CONDITIONS AND BRIEF PERIODS OF IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF SHOWERS AND/OR THUNDERSTORMS. 60 && .PREV DISCUSSION... /ISSUED 347 AM EDT SAT MAY 19 2012/ SHORT RANGE (TODAY-MONDAY)... RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL. THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO -11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING STRAIGHT LINE WINDS AND HAIL. TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND AFTERNOON SEA BREEZES. LONG RANGE (MONDAY NIGHT-FRIDAY)... THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30 PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER 70S. MARINE... A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF PERIODS WITH LOCALLY HIGHER WINDS AND SEAS. AVIATION... THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL BE DRY AGAIN. THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS FOR TODAY. FIRE WEATHER... SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS. THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE VERY POOR RANGE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 85 71 85 73 / 50 40 30 20 FORT LAUDERDALE 85 72 86 74 / 50 40 30 20 MIAMI 86 73 86 73 / 50 40 30 20 NAPLES 86 70 86 71 / 40 20 40 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...47/RGH AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
636 AM CDT SAT MAY 19 2012 .UPDATE... SEE THE CLIMATE SECTION REGARDING RECORD HIGHS FOR MAY 19TH. A VERY MINOR TWEAK WAS DONE WITH THE HRLY TEMPERATURES TO BETTER REFLECT CURRENT TRENDS. BASED ON FCST MAX TEMPERATURES TODAY SOME SITES MAY BE NEAR RECORD TERRITORY. EVERYTHING WILL DEPEND UPON THE AMOUNT OF CI/CS BLOW OFF FROM CONVECTION ALONG THE MISSOURI RIVER. RAP TRENDS WITH THE LIFT TOOL INDICATES THAT THIS CONVECTION WILL DISSIPATE DURING THE MORNING AS THE LLJ WEAKENS. THE OUTFLOW BOUNDARY WOULD PROVIDE A FOCUS FOR DIURNAL CONVECTION DURING THE AFTERNOON. THE LIFT TOOL AND RAP TRENDS STILL INDICATE CONVECTION SHOULD FIRE CLOSE TO THE MISSOURI RIVER THIS AFTERNOON BUT THERE MAY BE SOME ISOLATED TO SCATTERED CONVECTION DEVELOPING ON THE REMNANT OUTFLOW BOUNDARY IN CENTRAL IOWA LATE THIS AFTERNOON. THE LIFT TOOL STILL SUGGESTS THE LATE AFTERNOON AND EVENING HOURS SHOULD BE DRY IN THE CWFA. ..08.. && .AVIATION... VFR WX WILL BE SEEN THROUGH 09Z/20. INVERSION SHOULD BREAK 15Z- 16Z/19 ALLOWING DEEPER MIXING TO OCCUR AND INCREASE WINDS. WINDS SHOULD DROP OFF AROUND 00Z/20 AS THE INVERSION BECOMES RE- ESTABLISHED. KCID HAS THE BEST CHANCE AT SEEING VCTS AFT 09Z/20 BUT CONVECTION MAY HOLD OFF UNTIL 12Z/20 OR LATER. IF CONVECTION DOES OCCUR AT KCID THERE WOULD BE A POTENTIAL FOR MVFR CONDITIONS. KDBQ/KMLI/KBRL ARE EXPECTED TO REMAIN VFR THROUGH 12Z/20. ..08.. && .CLIMATE... RECORD HIGHS FOR MAY 19... MOLINE.........93 IN 1962 CEDAR RAPIDS...93 IN 1975 DUBUQUE........93 IN 1934 BURLINGTON.....93 IN 1998 && .PREV DISCUSSION... /ISSUED 305 AM CDT SAT MAY 19 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS THE FRONT WITH LOW PRESSURE CENTERS ALONG IT RUNNING FROM NORTHWEST MINNESOTA INTO NORTHERN COLORADO. A MESO HIGH ASSOCIATED WITH A SMALL MCS WAS ACROSS NEBRASKA WHILE A DRY LINE RAN FROM FROM NEAR KMCK TO KCVS. DEW POINTS WERE IN THE 40S ACROSS THE GREAT LAKES WITH 50S OVER MUCH OF THE MIDWEST. SHORT TERM...TODAY AND TONIGHT VERY WARM AND BREEZY CONDITIONS WILL BE SEEN ACROSS THE AREA TODAY. IF THE SAME NEAR 30 DEGREE DIURNAL SWING TAKES PLACE TODAY THEN MAX TEMPS WOULD BE IN THE LOW TO MID 90S. THE OVERALL WAA AND DEPTH OF DEEP MIXING JUST DOES NOT SUPPORT TEMPERATURES THAT WARM. HOWEVER... PERSISTENCE PLUS SEVERAL DEGREES WOULD SUPPORT UPPER 80S TO LOWER 90S FOR MAX TEMPS. DEW POINTS WILL BE ROUGHLY 10 DEGREES WARMER THAN YESTERDAY BUT HUMIDITY LEVELS WILL STILL BE LOW. TONIGHT...THE EVENING HOURS WILL BE DRY. MCS AND LIFT TOOLS INDICATE CONVECTION WILL FIRE LATE THIS AFTERNOON/EVENING IN WESTERN IOWA PROBABLY NOT FAR FROM THE MISSOURI RIVER. THE QUESTION IS WHETHER SAID CONVECTION WILL MAKE IT INTO THE CWFA PRIOR TO SUNRISE. INTERESTINGLY...ALL MODELS WEAKEN THE CONVERGENCE AFTER MIDNIGHT ACROSS THE AREA. MCS...LIFT...AND HEAVY RAIN TOOLS OFFER MIXED SIGNALS ON PRECIPITATION POTENTIAL. WHEN THE LIFT TOOL IS APPLIED TO ALL THE MODELS...A WEAK BUT CONSISTENT SIGNAL EMERGES SUGGESTING THE POSSIBILITY OF CONVECTION ENTERING THE FAR WESTERN CWFA JUST PRIOR TO DAWN. SO...WILL CONFINE ANY PRECIP TO VERY LATE TONIGHT OVER THE WESTERN QUARTER OR SO OF THE CWFA. HOWEVER...THE CONSISTENT WEAKENING OF THE OVERALL CONVERGENCE BY THE MODELS DOES QUESTION THE POTENTIAL FOR ANY PRECIPITATION ENTERING THE CWFA. ..08.. LONG TERM...SUNDAY THROUGH NEXT FRIDAY SUNDAY THROUGH SUNDAY EVENING CONTINUES TO REPRESENT A FRONTAL PASSAGE...WITH MODEST AT BEST MOISTURE...AND WEAK FORCING. THE TIMING APPEARS TO HAVE SLOWED JUST ENOUGH TO HAVE THE FRONT WITHIN EASTERN IOWA AT 18 TO 00Z...AND THUS A DIURNAL INCREASE IN CONVECTION SHOULD AFFECT OUR CWA UNLESS THE TIMING SPEEDS UP AGAIN. THE 18Z TO 00Z FROPA IS CONSISTENT IN MODEL GUIDANCE OTHER THAN THE NAM...WHICH REMAINS 3 HOURS FASTER. QPF SHOULD BE GENERALLY LIGHT...WITH BENEFICIAL AMOUNTS SPOTTY IN EXCESS OF A QUARTER INCH. ANY STRONG STORMS WILL DEPEND GREATLY ON CAPE...AND AT THIS POINT...WE ARE EXPECTING HIGHS IN THE LOWER TO MID 80S...WITH DEWPOINTS AROUND 60. THIS WILL BE SUFFICIENT FOR THUNDER...BUT DEPENDING ON WARM MID LEVEL TEMPS...WE MAY NOT SEE A LARGE CAPE POOL. BY LATER SUNDAY NIGHT...CAA AND DRY AIR SHOULD SWEEP IN...ENDING ANY RAINFALL THREAT. MONDAY THROUGH TUESDAY...COOLER CANADIAN AIR SHOULD BE OVER THE REGION...WITH HIGHS IN THE LOWER TO MID 70S...AND LOWS IN THE LOWER TO MID 50S. THIS TWO DAY PERIOD REPRESENTS THE COOLEST PORTION OF THE EXTENDED. WEDNESDAY NIGHT THROUGH FRIDAY...THERE REMAIN LARGE DIFFERENCES IN MODEL DATA. THE GFS CONTINUES TO SHIFT THE TROF/RIDGE EAST FAR ENOUGH DURING THIS PERIOD TO WARRANT SHOWERS AND THUNDERSTORMS IN OUR CWA BEGINNING THURSDAY. SHOULD THE GFS BE CORRECT...WITH SOME SUPPORT FROM THE UKMET AS WELL...THIS MAY BE THE BEGINNING OF A 2 TO 4 DAY PERIOD OF ACTIVE STORMS. HOWEVER...CAPPING IS MOST CERTAINLY GOING TO BE AN ISSUE...WITH THE ECMWF...CONSISTENTLY...SHOWING THE ENTIRE PERIOD BEING HOT AND COMPLETELY DRY. WHILE BOTH POSSIBILITIES REMAIN POSSIBLE...IT IS HARD TO IGNORE SUCH A STRONG ECMWF SIGNAL TOWARDS SUNSHINE AND HOT AIR. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
753 AM EDT SAT MAY 19 2012 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 508 AM EDT SAT MAY 19 2012 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE GREAT LAKES DOWNSTREAM OF TROF IN THE ROCKIES. CWA IS IN THE WARM SECTOR E OF SFC-H85 TROF/COLD FNT AND S OF WARM FNT OVER NRN LK SUP/ ADJOINING ONTARIO. WITH DRYNESS SHOWN ON LOCAL 00Z RAOBS /H925 DEWPT DEPRESSIONS ARE 15 TO 25C ON THE MPX/GRB RAOBS AND THE H85 DEWPT DEPRESSION AT GRB WAS 49C/...SKIES ARE MOCLR OVER UPR MI. DESPITE THE CLEAR SKIES/DRY AIR AND LOCAL DECOUPLING... TEMPS ARE WELL ABV NORMAL WITH STEADY SW FLOW AT H925 LIMITING THE OVERALL DIURNAL TEMP DROP. SOME SHRA/TS DID IMPACT MUCH OF MN THIS PAST EVNG DESPITE FAIRLY DRY AIR.AS SHRTWV LIFTED NNEWD WELL E OF THE MAIN TROF TO THE W...BUT THESE ARE TENDING TO WEAKEN AND STAY W OF EVEN LK SUP. MORE WIDESPREAD SHRA/TS ARE LOCATED IN THE PLAINS CLOSER TO H85 COLD FNT. MAIN FCST CONCERNS TDAY ARE FOCUSED ON FIRE WX. FOCUS FOR TNGT THRU SUN SHIFTS TO SHRA/TS CHCS ASSOCIATED WITH SLOWLY APRCHG UPR TROF/ COLD FNT. TDAY...CWA WL REMAIN UNDER WARM SW FLOW AS COLD FNT TO THE W SLIDES EWD THRU MN. ALTHOUGH H85 TEMPS ARE FCST TO AVG ABOUT A DEGREE LOWER THAN YDAY...VERY DEEP MIXING SHOWN ON THE 00Z MPX RAOB SHOULD SUPPORT MAX TEMPS NEARLY SIMILAR TO WHAT OCCURRED ON FRI PER UPSTREAM OBSVD SFC HI TEMPS...WITH SOME PLACES OVER THE W HALF SEEING THE MERCURY REACH 90. GOING FCST SHOWING THESE HIER TEMPS IN THE DOWNSLOPE AREAS FM ONTONAGON TO BARAGA LOOK ON TRACK. AREAS OVER THE E HALF SHOULD SEE SOME MODERATION OFF LK MI. SOME LK MODERATION MAY SLIP A BIT FARTHER W INTO THE CNTRL IF FCST BACKING WINDS TO MORE DUE S DRAGS THE LK MI MODERATION INTO THAT AREA. SEE FIRE WX SECTION BLO FOR A DISCUSSION OF FIRE WX CONCERNS. TNGT...WITH BLDG UPR RDG FCST OVER THE ERN GRT LKS...OPTED TO FOLLOW THE SOMEWHAT SLOWER 12Z ECMWF/00Z CNDN MODELS FOR THE TIMING OF THE COLD FNT...ESPECIALLY SINCE A SHRTWV LIFTING NEWD OUT OF THE ROCKIES WL INDUCE A LOW PRES TO DVLP ON THIS BNDRY OVER THE PLAINS TDAY. THIS LO IS FCST TO MOVE INTO MN BY 12Z SUN. THE 00Z NAM HAS TRENDED IN THIS DIRECTION AS WELL. IN FACT...THE 12Z ECMWF/0Z CNDN MODELS INDICATE THE BULK OF ANY PCPN WL BE ON THE COLD SIDE OF THE FNT AND STAY W OF IWD THRU 12Z. THIS FCST IS REASONABLE CONSIDERING THE DRYNESS OF THE WARM SECTOR AIRMASS AND FCST DEEP LYR QVECTOR CNVGC BEING FOCUSED UNDER THE SHARPER DPVA ASSOCIATED WITH THE SHRTWV ON THE COLD SIDE OF THE FNT IN MN EVEN AS LATE AS 12Z SUN. STEADY SW FLOW IN THE WARM SECTOR SHOULD ONCE AGAIN LIMIT THE DIURNAL FALL OF TEMP...SO MINS WL BE WELL ABV NORMAL AGAIN. SUN...SINCE THE FAVORED 12Z ECMWF/00Z CNDN MODELS SHOW BULK OF DEEP LYR QVECTOR CNVGC SHIFTING NEWD THRU WRN LK SUP TOWARD ONTARIO... SUSPECT THE HIER POPS WL BE OVER THE NW CWA...WITH PCPN TENDING TO DIMINISH AS THE FNT SHIFTS TO THE E INTO THE CENTRAL CWA BY LATE AFTN. HOWEVER...DAYTIME HEATING MAY OFFSET THE LOSS OF BEST DYNAMICS...ESPECIALLY SINCE THE CNDN MODEL SHOWS HIER H85 DWPTS UP TO 12C SURGING NEWD RIGHT ALONG THE FNT. HOWEVER...THIS SOMEWHAT HIER MSTR IS STILL RELATIVELY LO COMPARED TO H85 TEMPS FCST ARND 16C. SO THE LLVLS WL STILL BE RATHER DRY PER THE MODEL FCST SDNGS...LIMITING DESTABILIZATION. OPTED TO GO WITH LIKELY POPS OVER THE NW CWA...DIMINISHING TO CHC FARTHER TO THE E. RAISED FCST HI TEMPS WELL INTO THE 80S OVER THE E AND CNTRL AWAY FM LK MI MODERATION TO ACCOUNT FOR SLOWER ARRIVAL OF COLD FNT. SUN NGT...EXPECT COLD FNT TO PUSH THRU THE REST OF THE CWA ACCOMPANIED BY CHC POPS AS MAIN SHRTWV/SHARPEST DEEP LYR QVECTOR CNVGC EXITS TO THE NE AND ANY HELP FM DIURNAL HEATING WANES. SINCE GUIDANCE HINTS AT THE ARPCH OF A SECOND SHRTWV FM MN...MAINTAINED THE CHC POPS HANGING WELL BACK BEHIND THE COLD FNT AS HINTED AT BY 00Z NAM/12Z ECWMF AND SHOWN IN PREVIOUS FCST DESPITE MID LVL DRYING IN THE WAKE OF THE INITIAL DISTURBANCE. IF THIS TRAILING SHRTWV IS WEAKER...THE DRYING BEHIND THE FIRST STRONGER SHRTWV MAY END THE POPS FASTER THAN FCST AS FCST BY THE 00Z CNDN. THE ARRIVAL OF H85 TEMPS AOB 5C OVER THE W BY 12Z MON WL BRING A RETURN OF MORE SEASONABLE TEMPS. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 508 AM EDT SAT MAY 19 2012 A SLOWLY TRANSITIONING WX PATTERN...WITH MUCH OF THE PERIOD CONTINUING TO BE DOMINATED BY SOUTHERLY WINDS. INITIALLY WE WILL HAVE THE EXITING COLD FRONT TO OUR EAST...AND HIGH PRESSURE PUSHING IN FROM THE CENTRAL AND N PLAINS. AS A RESULT...EXPECT TEMPS TO BE 10 TO 15 DEGREES COOLER THAN SUNDAY. 850MB TEMPS WILL BE 4-5C. WITH THE COOL TEMPS WILL COME DRY AIR...WITH LOWER DEWPOINTS MONDAY AFTERNOON INTO THE MID 30S OVER THE W HALF. WOULD NOT BE COMPLETELY SHOCKED TO SEE VALUES CLOSER TO 30F...WHICH WOULD GIVE RH VALUES NEAR 25 PERCENT. THE SFC HIGH WILL BE DIRECTLY OVERHEAD TUESDAY MORNING...BEFORE SLIDING E. EXPECT THE RETURN OF S WINDS...AND A LITTLE BETTER MOISTURE. WE WILL SEE STRONGER SOUTHERLY WINDS RETURN BRIEFLY WEDNESDAY AFTERNOON. ADJUSTED MAX TEMPS UP OVER THE TRADITIONAL DOWNSLOPE AREAS NEAR LAKE SUPERIOR...WITH 850MB TEMPS RISING TO 11 TO 15C WITH THE COOLEST VALUES EAST. WENT ABOVE CONSENSUS FOR HIGH TEMPS THURSDAY...ONCE AGAIN WITH A MORE SIGNIFICANT INCREASE TO DOWNSLOPE AREAS. 850MB WINDS PEG OUT BETWEEN 45 AND 60KTS...AND TEMPS JUMP UP TO 15-18C. THE 19/00Z GFS IS ONE OF THE COOLEST SOLUTIONS. WILL BE INTERESTING HOW THE END OF THE WORK WEEK PANS OUT...AND IF THE FRONTAL BOUNDARY SETS UP AND STALLS OVER THE W CWA LIKE THE 19/00Z ECMWF...OR BLOWS THROUGH OUR AREA THURSDAY NIGHT BEFORE STALLING OVER LOWER MI FRIDAY INTO SATURDAY. WILL NOT GET TOO FANCY WITH THE FORECAST THAT FAR OUT...AND WILL KEEP THE SLIGHT CHANCE/LOW CHANCE POPS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 752 AM EDT SAT MAY 19 2012 VFR CONDITIONS WILL REMAIN...WITH HIGH CLOUDS SLOWLY INVADING FROM THE WEST AND LOWERING LOWER THE NEXT 24HRS. WINDS WILL CONTINUE TO BE THE MAIN STORY...WITH 30-40KT WINDS JUST ABOVE THE SFC AND MIXED LAYER THIS AFTERNOON...PARTICULARLY AT SAW AND IWD GIVEN THE FAVORABLE DOWNSLOPE FLOW. WHILE THERE IS A SMALL POSSIBILITY OF A SHOWER OR TS AT IWD JUST PRIOR TO DAYBREAK...BUT TOO SMALL OF A CHANCE TO INCLUDE IN THE TAFS QUITE YET. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT SAT MAY 19 2012 WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. LOW PRESSURE STRETCHING FROM SOUTHWESTERN QUEBEC TO NEBRASKA WILL SHIFT NORTHEASTWARD...FILLING SLIGHTLY AS IT CROSSES LAKE SUPERIOR SUNDAY INTO SUNDAY EVENING. BEHIND THIS FEATURE...HIGH PRESSURE WILL BUILD ACROSS THE UPPER GREAT LAKES MONDAY AND MONDAY NIGHT. EXPECT THE HIGH TO SLOWLY EXIT NORTHEASTWARD THROUGH MID WEEK...IN RESPONSE TO A STRONGER LOW NEARING FROM SOUTH CENTRAL CANADA THROUGH THE CENTRAL PLAINS. EXPECT THE LOW TO OUR WEST TO MOVE OVER ONTARIO ON THURSDAY...BEFORE EDGING ACROSS LAKE SUPERIOR THURSDAY NIGHT. && .FIRE WEATHER... ISSUED AT 508 AM EDT SAT MAY 19 2012 AFTER AN OVERNGT OF RELATIVELY POOR RH RECOVERY...EXPECT ANOTHER DAY OF AT LEAST NEAR CRITICAL FIRE WX PARAMETERS. MAX TEMPS THIS AFTN WILL BE SIMILAR TO WHAT WAS OBSVD YDAY...BUT DEEPER MIXING SHOWN ESPECIALLY ON THE 00Z MPX RAOB MIGHT TAP INTO LOWER DEWPTS. IN FACT...SFC DEWPTS WERE AS LO AS 35 TO 45 UPSTREAM YDAY AFTN IN WRN WI/SRN MN. BLENDED MIXED DEWPT TOOL VALUES WITH THE PREVIOUS FCST DEWPTS TO COME UP WITH READINGS DIPPING AS LO AS 43 OR SO. WITH WINDS ALOFT TDAY ALSO NEARLY SIMILAR TO YDAY AND DEEP MIXING RELATED TO DAYTIME HEATING... SUSTAINED WINDS AS HI AS 10 TO 20 MPH WITH GUSTS TO 30 MPH AT THE MORE EXPOSED LOCATIONS ARE LIKELY. OPTED TO ISSUE RFW FOR AN ARK FROM IWD/ONTONAGON TO BARAGA/MQT COUNTIES...AREAS THAT SAW THE POOREST RH RECOVERY EARLY THIS MRNG AND WHERE STRONGER WINDS/HIER DAYTIME HI TEMPS ARE MOST LIKELY. WL ISSUE RFD FOR THE OTHER COUNTIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... RED FLAG WARNING FROM 1 PM EDT /NOON CDT/ THIS AFTERNOON TO 8 PM EDT /7 PM CDT/ THIS EVENING FOR MIZ002-004-005-009-084. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...KF MARINE...KF FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
708 AM CDT SAT MAY 19 2012 .UPDATE... UPDATED FOR AVIATION DISCUSSION BELOW. && .DISCUSSION... /ISSUED 429 AM CDT SAT MAY 19 2012/ WATER VAPOR IMAGERY AND RUC H5 ANALYSIS SHOWS A RATHER EXPANSIVE RIDGE IN PLACE THIS MORNING EAST OF THE MS RIVER...WITH A RATHER COMPLEX TROUGH MOVING INTO THE HIGH PLAINS...WITH SEVERAL SHORTWAVES EMBEDDED WITHIN IT. THE TWO PRIMARY ONES ARE CURRENTLY OVER ERN SODAK AND MOVING FROM CO UP INTO SRN NEB. AT THE SFC...A COUPLE OF AREAS OF LOW PRESSURE COULD BE FOUND OVER FAR NW ONTARIO...WITH ANOTHER NEAR THE CO/NEB/KS BORDER. A COLD FRONT IS ANALYZED BETWEEN THESE LOWS ACROSS THE ERN DAKOTAS. FOR THE H5 PATTERN...THE RIDGING NOW MOVING ON TO THE HIGH PLAINS WILL SLOWLY BEAT DOWN THE ERN RIDGE...WITH THE TROUGH CURRENTLY COMING OUT OF CO WORKING ACROSS THE MPX CWA SUN INTO SUN EVENING. FOR MON/TUE...RIDGING WILL BE BUILDING IN ACROSS CENTRAL NOAM AS A SIGNIFICANT TROUGH DIGS INTO THE PAC NW. AS WE HEAD THROUGH THE SECOND HALF OF NEXT WEEK...THIS PATTERN LOOKS BECOME QUITE AMPLIFIED...AS VERY HIGH HEIGHTS SET UP INTO THE GREAT LAKES...WITH A QUASI-STATIONARY DEEP TROUGH TAKING HOLD ACROSS THE NRN ROCKIES...SETTING THE UPPER MIDWEST UP INTO A POTENTIAL ACTIVE PATTERN. AT THE SFC...THE COLD FRONT WILL WORK INTO WRN MN BY THIS AFTERNOON...AND CLEAR THE MPX WI COUNTIES SUN AFTERNOON. THE LOW CENTER CURRENTLY NEAR THE CO/NEB/KS WILL TRACK ACROSS SOUTH CENTRAL MN INTO THE WRN TIP OF THE U.P. OF MICH SAT NIGHT/SUN. HIGH PRESSURE WILL THEN SLIDE ACROSS THE AREA MON/TUE...BEFORE LEE SIDE TROUGHING REESTABLISHES ITSELF OVER THE NRN HIGH PLAINS WED. NEXT FRONT STILL ON TAP TO MOVE INTO MN WED NIGHT...AND WITH UPPER RIDGE AMPLIFYING OVER THE GREAT LAKES THE LATTER HALF OF NEXT WEEK...THIS FRONT STILL LOOKS TO STALL OUT THEN MEANDER AROUND THE UPPER MS VALLEY INTO THE HOLIDAY WEEKEND. THIS MORNING...STRONG WAA OUT AHEAD OF THE ERN SODAK SHORTWAVE HAS RESULTED IN THE DEVELOPMENT OF AN AREA OF TSRA OVER WRN MN...RADAR TRENDS MATCH WELL WITH THE IDEA THE RUC IS SHOWING...WITH THIS WAA AND ASSOCIATED ACTIVITY BASICALLY GOING DUE NORTH INTO NW MN. DO EXPECT CONDITIONS TO BE FAIRLY QUIET THROUGH THE MORNING...WITH THE SODAK SHORTWAVE AND COLD FRONT EXPECTED TO REMAIN WEST OF THE AREA. ONE CAVEAT IS THE LLJ AND STRONG MOISTURE TRANSPORT IN PLACE ACROSS THE WEST. THIS MAY KEEP SCT SHRA/TSRA ACTIVITY GOING THROUGH THE MORNING OUT WEST...BUT DID NOT PLAY THIS IDEA UP TO MUCH IN THE GRIDS. INSTEAD...WAITED UNTIL THE AFTERNOON TO REALLY GET POPS GOING. BY THEN THE COLD FRONT WILL BE WORKING INTO WRN MN AS UPPER ENERGY BEGINS TO WORK IN OVERHEAD. LOOKING AT HIRES REFLECTIVITY FORECASTS...SEEMS TO BE GOOD AGREEMENT WITH STORMS INITIATING NEAR A RWF TO LONG PRAIRIE LINE BETWEEN 20 AND 22Z...WITH ACTIVITY WORKING EAST TOWARD THE I-35 CORRIDOR SHORTLY AFTER 00Z. FORECAST SOUNDINGS AGAIN SHOW NICE INVERTED-V STRUCTURE THIS AFTERNOON...WITH MLCAPE AGAIN PUSHING UP TO AROUND 1500 J/KG. IN ADDITION...UNLIKE YESTERDAY...BULK SHEAR WILL BE IN THE 30-40 KT RANGE...INDICATING SOME BETTER ORGANIZATION IN CONVECTION IS POSSIBLE. GIVEN LESS FAVORABLE CONDITIONS MANAGED A FEW 60-70 MPH WIND GUSTS AND GOLF BALL SIZE HAIL FRIDAY...DO NOT SEE WHY WE DO NOT HAVE A SIMILAR THREAT FOR SEVERE WEATHER TODAY. IF ANYTHING...WOULD SUSPECT THE WIND THREAT IS A BIT HIGHER AS BETTER SHEAR AND FAVORABLE CONDITIONS FOR COLD POOL GENERATION MAY SUPPORT THE DEVELOPMENT OF ORGANIZED LINE SEGMENTS. BESIDE THE PRECIP...SHOULD BE ANOTHER WARM DAY...THOUGH NOT EXPECTING WIDESPREAD 90S LIKE FRIDAY. TWO LIMITING FACTORS FOR HIGHS TODAY WILL BE MORE CLOUD COVER AND ABOUT A 4 DEG C DROP IN H85 TEMPS. WITH THAT SAID...GUIDANCE HAS HAD A PRETTY STRONG COLD BIAS IN THIS HEAT WAVE...SO CONTINUED TO RUN WITH HIGHS A BIT HIGHER THAN WHAT MOST GUIDANCE WOULD SUGGEST. FOR TONIGHT...WITH THE ARRIVAL OF THE UPPER TROUGH AND ATTENDANT SFC LOW...WE CONTINUE TO SEE A STRONG SIGNAL FOR THE FORMATION OF A DEFORMATION BAND OF PRECIP JUST TO THE WEST OF THE SFC LOW TRACK. BLENDED THE ECMWF/GEM/SREF FOR PRECIP TONIGHT...WITH HEAVIEST BAND OF PRECIP EXPECTED TO SETUP BETWEEN THE WRN TWIN CITIES METRO AND MARSHALL/ALEXANDRIA. WITH THE SFC LOW COMING THROUGH...THIS REALLY SLOWS DOWN THE PRECIP...AND CONTINUED TO LEAN TIMING OF POPS ON SUN CLOSE TO THE ECMWF. THE ECMWF ALONG THE NAM/SREF WOULD INDICATE SUNDAY BEING CLOUDY/RAINY FOR MOST OF THE DAY SUNDAY ACROSS MOST OF THE MN MPX AREA...WITH HIGHS LIKELY NOT LEAVING THE LOWER 60S. FURTHER EAST...THE COLD FRONT/LOW SHOULD BE NEAR AN EAU/LADYSMITH LINE BY 18Z...SO SEVERE THREAT CERTAINLY LOOKS BETTER EAST...THOUGH A MARGINAL TREAT FOR SEVERE WEATHER CAN NOT BE RULED OUT IN THE FAR EAST. MON THROUGH WED STILL LOOK DRY AS HIGH PRESSURE SLIDES ACROSS THE AREA. BIGGEST THING TO WATCH WILL BE LOWS MONDAY MORNING. IF HIGHS ONLY TOP OUT AROUND 60 IN CENTRAL MN...WE COULD SEE LOWS MONDAY MORNING MAKE A RUN AT THE UPPER 30S AS HIGH PRESSURES MOVES IN AND SKIES CLEAR OUT. OTHER THAN THAT...ITS OFF TO WAITING FOR THE NEXT FRONT WEDNESDAY NIGHT. THE ONLY SIGNIFICANT CHANGE NOTED IN THE MODELS WITH THIS FRONT IS THE 19.00 ECMWF BASICALLY HALTS ITS EWRD PROGRESSION ACROSS WRN MN...WITH THE RAIN NOT MAKING IT TO ERN AREAS. AT ANY RATE...CONTINUED TO MENTION HIGH CHANCE/LIKELY POPS...ESPECIALLY WEST WED NIGHT. AFTER THAT...THE QUESTION BECOMES WHERE DOES THE FRONT SET UP. WHERE EVER IT DOES SETUP...NORTH OF THE BOUNDARY THROUGH THE WEEKEND IS LOOKING LIKE IT COULD BE A BREEDING GROUND FOR SOME ACTIVE WEATHER...CERTAINLY SOMETHING TO KEEP A CLOSE EYE ON AS WE HEAD INTO THE BUSY HOLIDAY WEEKEND. && .AVIATION.../12Z TAF ISSUANCE/ TWO MAIN ISSUES...TIMING OF STORMS TODAY/TONIGHT AND EVENTUAL MVFR/IFR LATER TONIGHT. SIGNIFICANT INFLUX OF MOISTURE IN WESTERN MN AHEAD OF FRONT. NEXT LOBE OF STORMS JUST ENTERING SW MN ASSOCIATED WITH WEAK SHORT WAVE. RWF/AXN/STC AT RISK FOR THUNDER LATE THIS MORNING INTO THE EARLY AFTERNOON FROM THIS. WEAKENING OF SYSTEM COULD RESULT IN ONLY SHOWERS BY THE TIME IT REACHES EASTERN MN DURING MIDDAY. BETTER LIFT LOOKS TO ARRIVE LATER THIS AFTERNOON AND HAVE ADDED THUNDER TO EASTERN MN AND WESTERN WI. CONFIDENCE IS ABOVE AVERAGE ON EXISTENCE OF STORMS... BUT BELOW AVERAGE ON TIMING... ESPECIALLY ON STORMS MID AFTERNOON INTO THE EVENING. EXPECT MVFR CEILINGS AND MAYBE VISIBILITIES TONIGHT WITH POST-FRONTAL RAIN. BEST CHANCE FOR IFR WILL BE THE KRWF TO KSTC AREA. KMSP...SHOWERS AND A FEW STORMS IN FAR SWRN MN INTO WESTERN IOWA AT THIS TIME. THINK THESE WILL WEAKEN BY THE TIME THEY REACH KMSP AND RESULT IN JUST SOME SCATTERED SHOWERS DURING MIDDAY...WITH A BELOW AVERAGE CHANCE THAT THERE WILL STILL BE THUNDER BY THE TIME PRECIP GETS HERE AROUND 18Z-19Z. BETTER CHANCE FOR THUNDER LATE AFTERNOON WITH NEXT WAVE. TIMING OF INCOMING COLD FRONT LOOKS TO BE AROUND 02Z-06Z FOLLOWED BY MVFR CEILINGS IN PRECIP. OUTLOOK... SUN...SHRA AND SOME TSRA POSSIBLE IN THE MORNING WITH MVFR/IFR POSSIBLE THEN IMPROVING CONDITIONS LATER ON SUNDAY. SUN NIGHT MON-TUE...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/TDK
AREA FORECAST DISCUSSION
NWS JACKSON MS
1030 AM CDT SAT MAY 19 2012 .UPDATE... A MOSTLY DRY FORECAST STILL LOOKS ON TRACK FOR THIS AFTERNOON...BUT HAVE ADDED MENTION OF ISOLATED TSTMS TO THE FORECAST BASED ON MORNING KJAN SOUNDING AND LATEST LOCAL-WRF AND HRRR GUIDANCE. EVEN THOUGH SYNOPTIC FEATURES CONTROLLING CONVECTIVE POTENTIAL TODAY ARE SUBTLE...WEAK CYCLONIC MID LEVEL FLOW IS IN PLACE WITH H500 TEMPERATURES ~ -12 C AND ACCAS IS APPARENT OVER SOUTHWEST MS. DEEP LAYER MOISTURE IS LIMITED WITH PRECIPITABLE WATER ~1.2 IN...BUT SFC DEWPOINTS AROUND 60F AND SFC TEMPS APPROACHING 90F WILL YIELD SFC-BASED CAPE EXCEEDING 2000 J/KG. HIGH RESOLUTION GUIDANCE SHOWING STRAY TSTM POTENTIAL LOOKS REASONABLE AND WILL RAISE POPS SLIGHTLY. SHOULD A FEW TSTMS DEVELOP...30-40 MPH WIND GUSTS WOULD BE A POSSIBILITY GIVEN DEEP SUB- CLOUD LAYER AND STEEP LOW LEVEL LAPSE RATES DCAPE VALUES > 1000 J/KG. AS SUGGESTED EARLIER THIS MORNING...THE AREAS ALONG AND NW OF THE NATCHEZ TRACE PARKWAY ARE MOST FAVORABLE FOR GETTING STORMS. THE UPDATED AVIATION DISCUSSION IS BELOW. /EC/ && .PREV DISCUSSION... /ISSUED 359 AM CDT SAT MAY 19 2012/ DISCUSSION...SHORT TERM(TODAY THROUGH SUNDAY NIGHT) THIS WEEKEND WILL BE CHARACTERIZED BY WARM TEMPERATURES AND MAINLY DRY CONDITIONS. THE REGION SITS UNDER HIGH PRESSURE AT THE SFC WITH A DEVELOPING LOW PRESSURE SYSTEM ACROSS THE PANHANDLE OF TEXAS. ALOFT...THE REGION SITS BETWEEN BROAD TROUGHING TO THE EAST AND BUILDING RIDGING TO THE WEST. CONDITIONS TODAY AND SUNDAY WILL BE SIMILAR TO PREVIOUS DAYS WITH CONTINUED WARM SUMMERLIKE TEMPERATURES...PERHAPS JUST A DEGREE OR TWO WARMER EACH DAY INTO THE UPPER 80S AND LOWER 90S. RAIN CHANCES WILL BE RATHER SLIM GIVEN INCREASED RIDGING IN THE WEST...LOW MOISTURE PER MODEL PW VALUES(THOUGH THAT HAS NOT SEEMED TO MATTER THE LAST FEW DAYS WITH VALUES LESS THAN 1 INCH AND STILL GENERATING SHOWERS)...AND NO DISCERNIBLE FORCING MECHANISM OTHER THAN DAYTIME HEATING. I CANNOT COMPLETELY RULE OUT SOME RAIN SHOWERS BUT PINPOINTING EXACTLY WHERE WILL BE DIFFICULT. SOME WRF AND HI-RES MODELS INDICATE MORE SHOWER ACTIVITY IN THE WEST THIS AFTERNOON BUT THIS IS ALSO WHERE THE BETTER RIDGING EXISTS. OVERNIGHT LOWS WILL BE IN THE UPPER 50S/LOWER 60S ACROSS THE REGION. COME SUNDAY NIGHT...A COLD FRONT WILL CONTINUE TO MAKE ITS WAY SOUTH TOWARD THE AREA. MOST OF THE RAIN SHOULD REMAIN OUT OF THE CWA THROUGH THE NIGHT BUT CLOSER TO DAYBREAK THERE COULD BE SOME SLIGHT CHANCES FOR THE DELTA AND HAVE INCREASED POPS IN THIS REGION JUST A LITTLE TO INTRODUCE SLIGHT CHANCE WORDING FOR THE PRE-DAWN HOURS./28/ LONGER TERM(MONDAY THROUGH SATURDAY)...SEVERAL FACTORS COMING TOGETHER FOR AT LEAST DECENT RAIN CHANCES MONDAY THROUGH TUESDAY TO START THE WORK WEEK. A MID-UPPER LEVEL TROUGH DRIVES SEWD DOWN THE MO RIVER VALLEY INTO THE TN VALLEY BY MONDAY NIGHT. THE TROUGH PUSHES AN AXIS OF 1.5 INCH PWAT AIR ALONG THE INCOMING FRONT THAT COMBINES WITH 14-1600J/KG MLCAPES AND NEAR 7C 7-500MB LAPSE RATES FOR A COUPLE OF ROUNDS OF SCATTERED TSRA MOSTLY TRIGGERED BY DAYTIME HEATING. THE FIRST ROUND GETS GOING ACROSS THE I-40 CORRIDOR EARLY MONDAY MORNING AND SAGS INTO OUR NRN CWFA BY MIDDAY WHEN K INDEXES REACH THE M30S. RATHER WEAK LOW AND MID LEVEL FLOW OF 15-25KTS WILL LIMIT INTENSITIES OF THE THESE SEWD- MOVING STORMS HOWEVER INTERACTING PREFRONTAL BOUNDARIES IN A RIBBON OF 330K THETA E 850MB AIR COULD PRODUCE A FEW STRONG STORMS MONDAY AFTERNOON GENERALLY N OF I-20. WILL MENTION THIS POTENTIAL IN THE HWOJAN. THEN...THE LEFTOVER ACTIVITY GRADUALLY WEAKENS MONDAY NIGHT BUT AT LEAST SOME SHRA PROBABLY PERSISTING. ONCE TUESDAY ARRIVES...THE BEST INSTABILITY REDEVELOPS ACROSS OUR SRN SECTIONS MAINLY S OF HIGHWAY 84 DURING THE MIDDAY AND AFTERNOON HOURS. THE COOLEST DAYTIME MAXES IN THE M-U80S FOR THE COMING WEEK SHOULD OCCUR AND AS A RESULT...WILL KEEP HIGHER POPS SHIFTED SWD TO THOSE LOCATIONS WITH THE FRONT PUSHING ALL THE WAY TO NEAR THE COAST TUESDAY EVENING. DRYING AIR SINKS INTO OUR N PORTIONS WHERE PWATS DROP BELOW 1 INCH LATE TUESDAY THROUGH TUESDAY NIGHT. THE AXIS OF HIGHER PWATS NEAR 1.4 INCHES PIVOTS BACK INTO THE REGION WEDNESDAY AFTERNOON HELPING TO SET OFF AT LEAST ISOLATED SHRA/TSRA. THE RETURNING WARM FRONT FEATURES NEAR 2K J/KG MLCAPES AND 335K THETA E 850MB AIR BUT GENERALLY EVEN WEAKER WIND PROFILES. WILL KEEP SMALL POPS FOR DAYTIME HEATING OF THE MOISTURE RETURN AS LOW LEVEL CONVERGENCE REMAINS WEAK. THEREAFTER...BUILDING MID LEVEL RIDGE ACROSS THE MID SOUTH AND TN VALLEY YIELDS 592DM 500MB HEIGHTS AND WARMING LOW LEVELS THAT PUSH 850MB TEMPS TO THE 17-19C RANGE FRIDAY AND SATURDAY. OVERNIGHT LOWS WILL STAY PREDOMINANTLY IN THE 60S WHILE EVEN MORE DAYTIME LOWER 90S SHOULD BE IN THE PICTURE JUST IN TIME FOR THE MEMORIAL DAY WEEKEND./40/ && .AVIATION...ISOLATED SHOWERS NOT OUT OF THE QUESTION AGAIN TODAY BUT CONFIDENCE IN AFFECTING A TAF SITE IS LOW AND WILL NOT BE INCLUDED IN THE FORECAST AT THIS POINT. EXPECT SCATTERED CUMULUS BASES DEVELOPING MIDDAY THROUGH AFTERNOON IN THE 6 TO 9 KFT RANGE. WINDS WILL BE FROM THE EAST THROUGH SOUTH AT 5 TO 10 KTS. TONIGHT WILL SEE SOME MORE SCATTERED MIST (MVFR LEVEL) LATE THAT WILL DISSIPATE BY 9 AM SUNDAY MORNING. CHANCES FOR RAIN SUNDAY AFTERNOON AGAIN APPEAR GENERALLY LOW WITH WINDS LIGHT. /BB/ && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$
AREA FORECAST DISCUSSION
NWS DENVER CO
1207 PM MDT SAT MAY 19 2012 .SHORT TERM...THE UPPER TROUGH IS RIGHT OVER THE CWA AT THIS TIME...WITH THE BEST CONVECTION OVER THE FOOTHILLS AND IMMEDIATE PLAINS. WITH THE AMOUNT OF CLOUD COVER EXPECTED...WILL LOWER HIGH TEMPERATURES A BIT. WILL MAKE MINOR ADJUSTMENTS TO POPS WITH REAL CONDITIONS IN MIND. .AVIATION...WILL HANG ON TO PRECIPITATION AND LOWER CEILINGS A BIT LONGER THIS AFTERNOON WITH CURRENT SITUATION IN MIND. WILL GET BACK TO NORMAL DIURNAL WIND PATTERNS AROUND 06Z TONIGHT. CEILINGS WILL GET ABOVE 5000 AGL BETWEEN 03Z AND 04Z THIS EVENING. && .PREV DISCUSSION... /ISSUED 353 AM MDT SAT MAY 19 2012/ SHORT TERM...WATER VAPOR IMAGERY SHOWING UPPER LOW NOW MOVING ACROSS WESTERN COLORADO WITH SCATTERED SHOWERS INCREASING ACROSS THE NORTHERN MOUNTAINS ATTM. RUC QG ANALYSIS SHOWING WEAK TO MODERATE ASCENT NOW INTO THE MOUNTAINS AND THIS WILL SPREAD OVER INTO THE NORTHEAST PLAINS THIS MORNING. MEANWHILE...COLD FRONT HAS MOVED THROUGH ALL OF NORTHEAST COLORADO WITH SHALLOW N-NE UPSLOPE FLOW DEVELOPING OVER THE PAST FEW HOURS. SURFACE DEWPOINTS HAVE BEEN RISING INTO THE MID 40S AND WE SHOULD START SEEING SOME STRATUS DEVELOPING BETWEEN 09-12Z ACROSS THE FRONT RANGE GIVEN THE ASCENT AND UPSLOPE DEVELOPING. SHORT RANGE MODELS STILL SHOWING A MOISTENING AIRMASS THIS MORNING WITH SHOWERS SPREADING OUT OVER THE PLAINS. CURRENT LIKELY POPS STILL SEEM REASONABLE BUT AMOUNTS STILL LOOK TO BE ON THE LOW SIDE AS THE TROF WILL MOVING MOVING RIGHT ALONG AND NOT A TON OF DEEP MOISTURE DEVELOPING WITH THIS QUICK MOVING SYSTEM. TEMPERATURES MUCH COOLER TODAY WITH READINGS ONLY IN THE 50S AND LOWER 60S OVER THE PLAINS. MAY SEE SOME LIGHT SNOW ACCUMULATIONS IN THE MOUNTAINS AND WITH THE MORE SCATTERED NATURE DON`T SEEM MUCH MORE THAN 2-4 INCHES IN THE HIGHER MOUNTAINS. POSSIBLY A BIT MORE IN THE HEAVIER EMBEDDED CONVECTIVE SNOW SHOWER. BOTH NAM/GFS SEEM A BIT HIGH WITH LIQUID AMOUNTS OVER AN INCH IN MOUNTAINS AND HIGHER EAST SLOPES. THE LOW WILL HAVE MOVED INTO WESTERN KANSAS BY LATE IN THE DAY WITH SUBSIDENCE SPREADING OVER THE PLAINS THIS AFTERNOON. HENCE A DECREASE IN SHOWER ACTIVITY AND ENDING IN MOST LOCALES DURING THE EVENING HOURS. GRADUAL CLEARING OVERNIGHT ACROSS THE ENTIRE AREA. LONG TERM...NORTHEAST COLORADO UNDER WEST-NORTHWESTERLY FLOW ALOFT WITH THE SHORTWAVE TROUGH CONTINUING ITS EASTWARD PROGRESSION ACROSS THE CENTRAL GREAT PLAINS DURING THE DAY SUNDAY. SHOULD SEE A WARMER DAY WITH A 2C WARMING AT 700 MBS. MODELS ALSO SHOW S-SELY SFC WINDS ON THE PLAINS STEADILY STRENGTHENING DURING THE DAY WHICH AIDS IN TRANSPORTING INCREASINGLY HUMID AIR NORTHWARD UP ALONG THE FRONT RANGE. STEEP LAPSE RATES DUE TO STG DAYTIME HEATING AND THE ARRIVAL OF THIS MOISTURE SHOULD SUPPORT AT LEAST ISOLATED T-STORM DEVELOP OVER AND NEAR THE FRONT RANGE DURING THE AFTERNOON AND EVENING HOURS. STORMS MOVING OUT ACROSS THE PLAINS MAY LINGER WELL INTO THE EVENING WITH THIS MOIST SELY INFLOW. ON MONDAY...FCST AREA BENEATH A STG 500 MB HIGH PRESSURE RIDGE WITH TEMPERATURES ALOFT CONTINUING TO WARM. A BRISK SOUTHERLY LOW- LEVEL FLOW ON THE PLAINS WILL CONTINUE TO ADVECT MOISTURE UP INTO THE AREA. BY AFTERNOON...MODELS SHOW AN 850-700 THETA-E RIDGE AXIS ALIGNED FM COLORADO SPRINGS TO JULESBURG. ALONG THIS AXIS SFC BASED CAPES PROGGED IN THE 1200-2000 KG/J RANGE BY LATE IN THE DAY. HOWEVER STG WARMING ALOFT AND WEAK CIN POSSIBLY ENOUGH TO SUPPRESS CONVECTION. FOR NOW WILL LEAVE OUT MENTION OF T-STORMS ON THE PLAINS...BUT CAN/T RULE THEM OUT ENTIRELY. WHEREAS WILL MENTION AT LEAST A SLIGHT CHANCE OF T-STORMS OVER AND NEAR THE FRONT RANGE FOR LATE IN THE DAY. GOING FOR TEMPERATURES ON MONDAY IN THE LOWER-MID 80S AT LOWER ELEVATIONS WITH UPPER 50S- 70S IN THE HIGH COUNTRY. BY TUESDAY...UPPER RIDGE MOVES EAST OF THE STATE PLACING THE AREA UNDER INCREASING SOUTHWESTERLY FLOW ALOFT. A DRIER MID-LEVEL WITH SUBSIDENCE ON THE SOUTH SIDE OF AN APPROACHING UPPER AIR TROUGH SHOULD RESULT IN PLENTY OF SUNSHINE DURING THE MORNING HOURS. COMBINATION OF UNSEASONABLY WARM TEMPERATURES...LOW HUMIDITY AND AND STEEP LAPSE RATES WILL LIKELY INCREASE THE WILDLAND FIRE DANGER IN MANY AREAS. NOT UNTIL LATE IN THE DAY WHEN THE UPPER TROUGH NEARS WILL SEE CONVECTION...MOST OF WHICH SHOULD BE CONFINED TO THE HIGHER TERRAIN NORTH OF I-70. SHOULD SEE ANOTHER DAY OF VERY WARM TEMPERATURES WITH HIGHS PUSHING THE 90 DEG MARK ON THE PLAINS. BY WEDNESDAY TEMPERATURES TURN COOLER WITH PASSAGE OF THE UPPER TROUGH AND PASSAGE OF A COLD FRONT DURING THE DAY. SHOULD SEE THE CHANCE FOR SHOWERS AND T-STORMS ALSO INCREASE. THE UPPER TROUGH PASSES TO THE EAST OVERNIGHT RESULTING IN A SLIGHT MODERATION IN TEMPERATURE AND A REDUCED CHANCE IN PRECIP. FOR LATER IN THE WEEK...SHOULD SEE STEADY WARMING WITH THE RETURN OF RIDGING. AVIATION...CEILINGS LOWERING BY DAYBREAK WITH MAINLY MVFR/ILS APPROACHES THROUGH THIS MORNING WITH RAIN SHOWERS AND THEN IMPROVING TRENDS DURING THE AFTERNOON. SURFACE WINDS SHOULD REMAIN N-NE TODAY BEFORE SHIFTING SE-S BY LATER THIS EVENING AND A RETURN TO DRAINAGE. HYDROLOGY...RAINFALL AMOUNTS LOOK TO BE IN THE QUARTER TO HALF INCH RANGE FOR TODAY WITH RAINFALL RATES GENERALLY A TENTH OF AN INCH PER HOUR OR LESS WITH THE SHOWERS. ANY FLOODING POTENTIAL IN THE BURN AREAS SEEM LOW. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RJK/ENTREKIN LONG TERM....BAKER AVIATION...RJK/ENTREKIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
147 PM EDT SAT MAY 19 2012 .AVIATION... CONVECTION HAS STARTED ACROSS THE SOUTH FLORIDA PENINSULA. THE MOST ACTIVE REGION IS ACROSS THE EASTERN HALF WITH ALL TERMINALS ASSIGNED VCTS. FOR TERMINAL KAPF...ALSO ASSIGNED VCTS WITH CONVECTION STARTING JUST INLAND OF THE TERMINAL. THERE IS THE POTENTIAL FOR SOME STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON WITH THE EAST COAST TERMINALS BEING THE MOST LIKELY TO BE AFFECTED WITH PERIODS OF MVFR TO IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF ANY SHOWERS OR THUNDERSTORMS. CONVECTION WILL LIKELY LINGER INTO EVENING HOURS AND SUBSIDE THEREAFTER. 60 60 && .PREV DISCUSSION... /ISSUED 1015 AM EDT SAT MAY 19 2012/ UPDATE...UPDATED FORECAST PACKAGE TO MENTION POSSIBLE STRONG TO SEVERE STORMS THIS AFTERNOON. 12Z SOUNDING PARAMETERS ALMOST IDENTICAL TO FRIDAY`S VALUES. PW=1.72 INCHES, 500 MB TEMP AROUND -10C TO -11C AND THE LIKELIHOOD OF WET MICROBURSTS AND LARGE HAIL. 850 MB ANALYSIS ALSO SHOWS A WEAK TROUGH MOVING SLOWLY EASTWARD ACROSS SOUTH FLORIDA. THIS COMBINED WITH PLENTY OF HEATING AND LEFT-OVER OUTFLOW BOUNDARIES FROM YESTERDAY`S CONVECTIVE ACTIVITY WILL LEAD TO THUNDERSTORMS DEVELOPING JUST ABOUT ANYWHERE IN S. FLORIDA. HOWEVER, WESTERLY MID/UPPER LEVEL FLOW MAY STEER ANY STORM EASTWARD TOWARD THE EASTERN INTERIOR AND EASTERN METRO AREAS. AVIATION... THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 16Z TODAY...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. CONVECTION IS EXPECTED ACROSS THE PENINSULA TODAY...WITH VCSH ASSIGNED ALL TERMINALS THROUGH 15Z AND VCTS ASSIGNED ALL TERMINALS AT 16Z. MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS THROUGH 15Z AND STARTING AT 16Z PERIODS OF SUB-VFR CONDITIONS AND BRIEF PERIODS OF IFR CONDITIONS POSSIBLE WITH OCCURRENCE OF SHOWERS AND/OR THUNDERSTORMS. 60 PREV DISCUSSION... /ISSUED 347 AM EDT SAT MAY 19 2012/ SHORT RANGE (TODAY-MONDAY)... RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD TROUGH CENTERED OVER THE SOUTHEAST WITH A NOTABLE SHORTWAVE TROUGH EXTENDING SOUTHWEST FROM THE FLORIDA PANHANDLE TO THE CENTRAL GULF AND PLENTY OF MID/UPPER MOISTURE SPREADING EAST-NORTHEAST ACROSS SOUTH FLORIDA...THE KEYS AND FLORIDA STRAITS. THE LATEST SURFACE ANALYSIS SHOWED A WEAKNESS WITHIN THE SUBTROPICAL RIDGE ACROSS THE LOCAL AREA WITH A TROUGH OR FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM A LOW PRESSURE CENTERED OFF THE CAROLINA COAST TO CENTRAL FL. THE MODELS HAVE INITIALIZED WELL WITH THIS SYNOPTIC PATTERN AND INDICATE ANOTHER POTENTIALLY ACTIVE DAY ACROSS THE FLORIDA PENINSULA...SIMILAR TO YESTERDAY. THE AFOREMENTIONED SHORTWAVE TROUGH WILL ROTATE EASTWARD AROUND THE BASE OF THE UPPER TROUGH AND MOVE ACROSS THE AREA TODAY FROM WEST TO EAST...WHICH WILL LEAD TO DECREASING UPPER HEIGHTS AND SOME COOLER MID-LEVEL AIR (-10 TO -11 C 500 MB TEMPS) SPREADING OVER THE AREA THIS AFTERNOON. THIS COMBINED WITH A WEAK SFC TROUGH AND LOW-LEVEL CONVERGENCE ASSOCIATED WITH THE EAST/WEST COAST SEA BREEZES WILL BE ENOUGH TO INITIATE ANOTHER ROUND OF AFTERNOON CONVECTION. THE ONE DIFFERENCE TODAY COMPARED TO YESTERDAY IS THAT THE LOW-LEVEL FLOW WILL HAVE MORE OF AN EASTERLY COMPONENT...WHICH SHOULD HELP CONCENTRATE THE CONVECTIVE ACTIVITY OVER THE INTERIOR SECTIONS INITIALLY. THE LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THIS AND GENERALLY INDICATE CONVECTION BEGINNING BY 18Z OVER THESE INTERIOR LOCATIONS. WITH THE DRIER/COOLER MID-LEVEL AIR EXPECTED...THE MAIN THREATS WITH THE STRONGER STORMS THAT DEVELOP WILL BE DAMAGING STRAIGHT LINE WINDS AND HAIL. TONIGHT THROUGH MONDAY...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH SCATTERED AFTERNOON SHOWERS/TSTMS DEVELOPING OVER THE INTERIOR SECTIONS ASSOCIATED WITH THE PERSISTENT UPPER TROUGH AND AFTERNOON SEA BREEZES. LONG RANGE (MONDAY NIGHT-FRIDAY)... THE GFS/GFS ENSEMBLE MEAN/ECMWF GENERALLY ALL MAINTAIN THE MID/UPPER TROUGH OVER THE SOUTHEAST REGION WITH DRY MID/UPPER WESTERLY FLOW CONTINUING ACROSS THE FL PENINSULA. AT THE SURFACE...ALTHOUGH THERE REMAINS SOME DIFFERENCES NOTED BETWEEN THE MODEL SOLUTIONS...THE GFS/ECMWF GENERALLY INDICATE A WEAK TROUGH EXTENDING NORTHEAST FROM A BROAD LOW CENTERED OVER THE WESTERN CARIBBEAN ACROSS THE FLORIDA STRAITS...WHICH MAY HELP CONCENTRATE ANY DEEP MOIST CONVECTION JUST SOUTH OF OUR LOCAL AREA ACROSS THE KEYS AND STRAITS. OTHERWISE...MORE OF A SEASONAL PATTERN WITH 20-30 PERCENT RAINFALL CHANCES EACH DAY ASSOCIATED WITH THE AFTERNOON SEA BREEZES WILL REMAIN IN THE FORECAST. TEMPERATURES WILL REMAIN AROUND NORMAL THROUGH THIS TIME WITH HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER 70S. MARINE... A WEAK PRESSURE GRADIENT WILL RESULT IN LIGHT EASTERLY WINDS AND LOW SEAS CONTINUING THROUGH THE WEEKEND AND INTO THE UPCOMING WEEK. SCATTERED SHOWERS AND THUNDERSTORMS COULD LEAD TO BRIEF PERIODS WITH LOCALLY HIGHER WINDS AND SEAS. AVIATION... THE WINDS WILL REMAIN LIGHT EARLY THIS MORNING BEFORE BECOMING SOUTHEAST AT 5 TO 10 KNOTS AFTER 13Z TODAY. THE ONLY EXCEPTION TO THIS IS AT KAPF WHERE THE WINDS WILL BE EASTERLY THIS MORNING BEFORE SWINGING TO A WESTERLY DIRECTION AROUND 17Z TODAY...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. THE WEATHER WILL ALSO REMAIN DRY THROUGH 13Z TODAY...BEFORE VCSH FOR ALL TAF SITES BETWEEN 13Z AND 17Z. THUNDERSTORMS WILL THEN DEVELOP THIS AFTERNOON ALONG THE SEA BREEZE AND PUSH SLOWLY INLAND OVER THE COAST AREAS...WHILE THE WEST COAST SEA BREEZE PUSHES MORE INLAND. SO WILL INTRODUCE VCTS FOR THE EAST COAST TAF SITES BETWEEN 17Z AND 23Z TODAY...WHILE THE KAPF TAF SITE REMAINS IN THE VCSH FOR THE AFTERNOON HOURS. THE ACTIVITY WILL THEN DISSIPATE BETWEEN 00Z AND 02Z TONIGHT OVER ALL OF THE TAF SITES...AS THE HEATING OF THE DAY IS LOST. SO AFTER 02Z TONIGHT THE WEATHER WILL BE DRY AGAIN. THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS THROUGH TODAY...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS FOR TODAY. FIRE WEATHER... SOME STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON OVER SOUTH FLORIDA ESPECIALLY WHERE THE EAST AND WEST COAST SEA BREEZES COLLIDE OVER THE INTERIOR AREAS. THE PRIMARY IMPACTS FROM THE STRONGEST STORMS WILL BE FREQUENT LIGHTNING STRIKES...GUSTY WINDS...HAIL UP TO QUARTER SIZE...AND HEAVY RAINFALL. THE BEST TIME TO SEE THE STORMS WILL IN THE AFTERNOON AND EARLY EVENING HOURS. THE RELATIVE HUMIDITIES TODAY WILL REMAIN ABOVE THE 35 PERCENT CRITICAL VALUE..AS THE DISPERSION INDEX WILL RANGE FROM THE 20S INTERIOR AREAS TO 40 ALONG THE METRO AREAS. THE DISPERSION INDEX FOR TONIGHT WILL BE LESS THAN 5. THIS MEANS THAT THE MIXING FOR TODAY IS IN THE FAIR TO GOOD RANGE...WHILE TONIGHT IT IS IN THE VERY POOR RANGE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 71 85 73 86 / 40 30 20 30 FORT LAUDERDALE 72 86 74 86 / 40 30 20 30 MIAMI 73 86 73 87 / 40 30 20 30 NAPLES 70 86 71 87 / 20 40 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...47/RGH AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS WICHITA KS
314 PM CDT SAT MAY 19 2012 .DISCUSSION... SYNOPSIS...SURFACE LOW PRESSURE WAS CENTERED NEAR GREAT BEND AT 18Z. THIS LOW WAS PART OF A COLD FRONT THAT EXTENDED FROM CENTRAL MINNESOTA /AND AREAS FURTHER NORTH/...TO THE TEXAS PANHANDLE. A STRONG UPPER LEVEL DISTURBANCE WAS ADVANCING NORTHEASTWARD ACROSS SOUTHWEST NEBRASKA. THIS WILL BRING DESTABILIZING COOLER AIR IN THE MID LEVELS TO THE REGION...CAUSING SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG THE FRONT. THESE ARE ALSO A BIG PART OF THE STORMS ONGOING ACROSS WESTERN KANSAS AND WESTERN NEBRASKA. AS OF 1945Z...THE LEADING EDGE OF THIS CAN BE SEEN WELL ON WATER VAPOR MOVING ACROSS WESTERN KANSAS. TONIGHT... THE FRONT WILL CONTINUE MOVING SOUTHEAST THIS EVENING. RUC SHOWING SIGNIFICANT COLD ADVECTION ONGOING WITH THE APPROACHING DISTURBANCE. DURING THE DAY...THE CONVERGENCE ALONG THE FRONT HAS HAD A HARD TIME GETTING GOING AS THE WINDS HAVE VEERED AHEAD OF THE FRONT. THIS HAS ADDED TO THE UNCERTAINTY OF WHEN CONVECTION IS EXPECTED TO DEVELOP...BUT SHOULD BE BY 23Z. 0-6KM SHEAR IS MARGINAL FOR ORGANIZED CONVECTION...WITH VALUES RANGING FROM 30-35 KNOTS. THAT SAID...THERE IS ENOUGH INSTABILITY FOR SOME OF THE STORMS TO BECOME SEVERE. SUNDAY...THE FRONT SHOULD MAKE IT WELL INTO SOUTHEAST KANSAS. WITH THE MAIN UPPER LEVEL SUPPORT FAR REMOVED FROM THE FRONT...ORGANIZED SEVERE STORMS LOOK UNLIKELY AT THIS TIME...THOUGH SOME SCATTERED STORMS EXPECTED. MONDAY-SATURDAY... HIGH PRESSURE WILL REMAIN ACROSS THE REGION THROUGH TUESDAY. THE FRONT THAT JUST MOVED THROUGH WILL RETREAT NORTHWARD AS A WARM FRONT. LEE CYCLOGENESIS TAKES PLACE AND BY WEDNESDAY...STRONG SOUTHWESTERLY WINDS DEVELOP AGAIN AT THE SURFACE. THIS WILL ALL RESULT IN A WARMING TREND IN THE MIDDLE AND LATTERN PORTION OF THE WEEK. BY FRIDAY...A DEEP UPPER LEVEL TROUGH DEVELOPS OVER THE PACIFIC COAST WITH RIDGING OVER THE SOUTHEAST. THIS WILL KEEP ALL OF THE SIGNIFICANT PRECIPITATION WELL TO THE NORTH. COOK && .AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN HAZARDS: WINDS AHEAD OF/BEHIND COLD FRONT...AND THUNDERSTORMS. S-SWRLY GUSTS 25-35KT WILL PERSIST AHEAD OF FRONT THIS PM/EARLY EVE. COLD FRONT SHOULD REACH RSL AROUND 20-21Z...SLN/HUT 01-02Z...AND ICT ~03-04Z. SCATTERED-BROKEN LINE OF THUNDERSTORMS SHOULD DEVELOP ALONG THE FRONT LATE THIS PM/EVE WHICH COULD PRODUCE OUTFLOW AHEAD OF ACTUAL FRONT. WIND GUSTS 40-50 KT AND HAIL WOULD BE THE MAIN THREATS FROM THESE STORMS. WILL CARRY TEMPO TS AT HUT/SLN SITES WITH HIGHEST CONFIDENCE OF STORMS AFFECTING THOSE SITES...AND VCTS AT ICT. WIND SHIFT TO NW WITH SOME GUSTS 20-25 KT THIS EVE IN CENTRAL/SOUTH CENTRAL KS. JMC && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 58 79 57 80 / 50 20 10 0 HUTCHINSON 56 78 54 80 / 50 10 0 0 NEWTON 57 77 53 78 / 50 20 10 0 ELDORADO 59 78 54 79 / 40 20 10 0 WINFIELD-KWLD 61 79 58 80 / 40 30 20 10 RUSSELL 52 77 51 81 / 20 10 0 0 GREAT BEND 53 78 52 81 / 20 10 0 0 SALINA 56 78 51 80 / 50 10 0 0 MCPHERSON 57 77 52 79 / 50 10 0 0 COFFEYVILLE 65 81 59 79 / 30 40 30 10 CHANUTE 64 79 57 78 / 40 40 10 10 IOLA 64 78 57 77 / 30 40 10 10 PARSONS-KPPF 65 80 58 78 / 30 40 20 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
619 PM EDT SAT MAY 19 2012 .SYNOPSIS... HIGH PRESSURE WILL ALLOW FOR DRY AND UNSEASONABLY WARM WEATHER TO CONTINUE INTO EARLY MONDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL RETURN AS A LOW PULLS MOISTURE INTO THE AREA FROM THE SOUTHEAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST. && .NEAR TERM /THROUGH SUNDAY/... MINOR CHANGES TO PREVIOUS FORECAST, INCREASED OVERNIGHT LOWS A COUPLE OF DEGREES AND MADE TWEAKS TO CLOUD COVER. PREVIOUS DISCUSSION... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE EXTENDING FROM THE THE OHIO VALLEY INTO NEW ENGLAND WITH ITS ASSOCIATED WEAK ANTI-CYCLONIC FLOW CENTERED ACROSS THE OHIO VALLEY. MEANWHILE, A CLOSED LOW IS LOCATED OFF THE CAROLINA COAST. AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE IS CENTERED ACROSS THE NORTHEAST, EXTENDING SOUTHWESTWARD INTO THE REGION. THE RIDGE WILL SHIFT FURTHER NORTHEAST TONIGHT AND TOMORROW, ALLOWING FOR DRY WEATHER TO CONTINUE WITH UNSEASONABLY WARM HIGH TEMPS. SKIES WILL BE MOSTLY CLEAR THROUGH THIS PERIOD, ASIDE FROM SOME HIGH CIRRUS SPILLING INTO THE AREA AHEAD OF THE LOW TO THE SOUTHEAST. DESPITE TEMPS IN THE LOW TO MID 80S FOR HIGHS, DRY AIR IN PLACE ALONG WITH NEAR CALM WINDS AND MOSTLY CLEAR SKIES OVERNIGHT WILL ALLOW FOR ANOTHER NIGHT OF DECENT RADIATIONAL COOLING. THUS, LOWS ARE A MAV/MET BLEND, DROPPING TO NEAR NORMAL SEASONAL VALUES, IN THE LOW TO MID 50S ACROSS THE AREA. THE GFS INDICATES 850 TEMPS AROUND 15C TOMORROW. THIS WILL CONTRIBUTE TO YET ANOTHER DAY WITH HIGHS 10-15 DEGREES ABOVE NORMAL, RANGING FROM THE MID 80S ACROSS THE LOWLANDS TO THE MID 70S ACROSS THE EASTERN RIDGES. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... GFS/ECMWF INDICATE THE RIDGE AXIS BECOMING PINCHED OFF SUNDAY NIGHT INTO MONDAY AS THE UPPER LOW MOVES INTO VIRGINIA AND A TROUGH MOVES INTO THE UPPER MIDWEST. THE CLOSED LOW WILL SERVE TO DRAW MOISTURE INTO THE AREA FROM THE ATLANTIC. WITH THIS IN MIND, THE CHANCE OF SHOWERS BEGINS SOUTHEAST OF PITTSBURGH ON MONDAY MORNING. IN ASSOCIATION WITH THE TROUGH, A FRONTAL BOUNDARY WILL CROSS THE OHIO VALLEY ON MONDAY AFTERNOON. INCREASING MOISTURE AND INSTABILITY AHEAD OF THIS FEATURE WILL LEAD TO THE CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY AFTERNOON THROUGH THE EVENING. INCREASED CLOUD COVERAGE AND COOLER TEMPS ALOFT ASSOCIATED WITH THE LOW APPROACHING FROM THE SOUTHEAST WILL ALLOW FOR A SLIGHT COOLER DAY ON MONDAY, WITH HIGH TEMPS AT 5 TO 10 DEGREES ABOVE NORMAL, RANGING FROM THE LOWER 80S ACROSS EASTERN OHIO TO NEAR 70 ACROSS THE EASTERN RIDGES. SOME MODEL UNCERTAINTY ENTERS THE FORECAST IN REGARDS TO THE TROUGH MOVING INTO THE AREA FROM THE UPPER MIDWEST. ECMWF/NAM SOLUTIONS MERGE THE UPPER LOW TO THE SOUTHEAST WITH THIS FEATURE INTO A MORE AMPLIFIED TROUGH ACROSS THE AREA. MEANWHILE, THE GFS MOVES THE UPPER LOW UP THE EAST COAST AND BRINGS A WEAKER TROUGH ACROSS THE AREA. WITH THIS UNCERTAINTY IN MIND AND THE SLOW PASSAGE OF A FRONTAL BOUNDARY, FORECAST IS A BLEND OF THE SOLUTIONS, CONTINUING A CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT INTO TUESDAY. WITH INCREASED CLOUD COVERAGE WITH SHOWERS AND THUNDERSTORMS, HIGHS ON TUESDAY WILL BE SLIGHTLY COOLER IN COMPARISON TO THE WEEKEND AND MONDAY, ALTHOUGH STILL AROUND 5 DEGREES ABOVE NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... 12Z GFS/00Z ECMWF HAVE DIFFERENT DEPICTIONS IN THE EXTENDED...AND THEREFORE CONFIDENCE IS BELOW AVERAGE. BOTH MODELS SHOW GENERAL AGREEMENT THAT THERE WILL BE A NEARLY STATIONARY UPPER LEVEL LOW/TROUGH NEAR THE CAROLINAS. HOWEVER...MULTIPLE RUNS OF THE GFS KEEPS THIS FEATURE OVER THE ATLANTIC OCEAN WITH JUST SOME CLOUDS LOCALLY...WHILE THE ECMWF HAS THE FEATURE INLAND ALONG THE EAST COAST AND SPREADS RAIN AS FAR WEST AS WEST VIRGINIA AND EASTERN OHIO. WITH NAEFS AND ECMWF ENSEMBLE KEEPING THE PATTERN A LITTLE DRIER...HAVE ALSO STUCK WITH A DRIER FORECAST. IF THIS HOLDS...AND THE GFS FORECAST VERIFIES...THIS PERIOD WILL BE QUITE WARM. GFS BIAS-CORRECTED GRIDS AND NAEFS METEOGRAMS SUGGEST THAT 90 DEGREES IS NOT OUT OF THE QUESTION FOR THE START OF THE MEMORIAL DAY WEEKEND. && .AVIATION /22Z SATURDAY THROUGH THURSDAY/... HIGH PRESSURE WILL KEEP SKIES MOSTLY CLEAR AND WINDS BELOW 10 KTS FOR NEXT 24 HOURS. THE ONLY CLOUDS THAT ARE EXPECTED WILL BE WITH BLOWOFF FROM POSSIBLE TROPICAL SYSTEM OFF CAROLINAS. .OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY... SUNDAY NIGHT SHOULD REMAIN DRY BEFORE COLD FRONT APPROACHES FROM THE WEST ON MONDAY. CONVECTION WILL ALSO INCREASE FROM THE EAST. SLOW MOVING FRONT WILL BRING A CONTINUED CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. PRECIPITATION SHOULD THEN SHIFT EAST OF THE AREA BY WEDNESDAY NIGHT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
342 PM EDT SAT MAY 19 2012 .SYNOPSIS... HIGH PRESSURE WILL ALLOW FOR DRY AND UNSEASONABLY WARM WEATHER TO CONTINUE INTO EARLY MONDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL RETURN AS A LOW PULLS MOISTURE INTO THE AREA FROM THE SOUTHEAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST. && .NEAR TERM /THROUGH SUNDAY/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE EXTENDING FROM THE THE OHIO VALLEY INTO NEW ENGLAND WITH ITS ASSOCIATED WEAK ANTI-CYCLONIC FLOW CENTERED ACROSS THE OHIO VALLEY. MEANWHILE, A CLOSED LOW IS LOCATED OFF THE CAROLINA COAST. AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE IS CENTERED ACROSS THE NORTHEAST, EXTENDING SOUTHWESTWARD INTO THE REGION. THE RIDGE WILL SHIFT FURTHER NORTHEAST TONIGHT AND TOMORROW, ALLOWING FOR DRY WEATHER TO CONTINUE WITH UNSEASONABLY WARM HIGH TEMPS. SKIES WILL BE MOSTLY CLEAR THROUGH THIS PERIOD, ASIDE FROM SOME HIGH CIRRUS SPILLING INTO THE AREA AHEAD OF THE LOW TO THE SOUTHEAST. DESPITE TEMPS IN THE LOW TO MID 80S FOR HIGHS, DRY AIR IN PLACE ALONG WITH NEAR CALM WINDS AND MOSTLY CLEAR SKIES OVERNIGHT WILL ALLOW FOR ANOTHER NIGHT OF DECENT RADIATIONAL COOLING. THUS, LOWS ARE A MAV/MET BLEND, DROPPING TO NEAR NORMAL SEASONAL VALUES, IN THE LOW TO MID 50S ACROSS THE AREA. THE GFS INDICATES 850 TEMPS AROUND 15C TOMORROW. THIS WILL CONTRIBUTE TO YET ANOTHER DAY WITH HIGHS 10-15 DEGREES ABOVE NORMAL, RANGING FROM THE MID 80S ACROSS THE LOWLANDS TO THE MID 70S ACROSS THE EASTERN RIDGES. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... GFS/ECMWF INDICATE THE RIDGE AXIS BECOMING PINCHED OFF SUNDAY NIGHT INTO MONDAY AS THE UPPER LOW MOVES INTO VIRGINIA AND A TROUGH MOVES INTO THE UPPER MIDWEST. THE CLOSED LOW WILL SERVE TO DRAW MOISTURE INTO THE AREA FROM THE ATLANTIC. WITH THIS IN MIND, THE CHANCE OF SHOWERS BEGINS SOUTHEAST OF PITTSBURGH ON MONDAY MORNING. IN ASSOCIATION WITH THE TROUGH, A FRONTAL BOUNDARY WILL CROSS THE OHIO VALLEY ON MONDAY AFTERNOON. INCREASING MOISTURE AND INSTABILITY AHEAD OF THIS FEATURE WILL LEAD TO THE CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY AFTERNOON THROUGH THE EVENING. INCREASED CLOUD COVERAGE AND COOLER TEMPS ALOFT ASSOCIATED WITH THE LOW APPROACHING FROM THE SOUTHEAST WILL ALLOW FOR A SLIGHT COOLER DAY ON MONDAY, WITH HIGH TEMPS AT 5 TO 10 DEGREES ABOVE NORMAL, RANGING FROM THE LOWER 80S ACROSS EASTERN OHIO TO NEAR 70 ACROSS THE EASTERN RIDGES. SOME MODEL UNCERTAINTY ENTERS THE FORECAST IN REGARDS TO THE TROUGH MOVING INTO THE AREA FROM THE UPPER MIDWEST. ECMWF/NAM SOLUTIONS MERGE THE UPPER LOW TO THE SOUTHEAST WITH THIS FEATURE INTO A MORE AMPLIFIED TROUGH ACROSS THE AREA. MEANWHILE, THE GFS MOVES THE UPPER LOW UP THE EAST COAST AND BRINGS A WEAKER TROUGH ACROSS THE AREA. WITH THIS UNCERTAINTY IN MIND AND THE SLOW PASSAGE OF A FRONTAL BOUNDARY, FORECAST IS A BLEND OF THE SOLUTIONS, CONTINUING A CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT INTO TUESDAY. WITH INCREASED CLOUD COVERAGE WITH SHOWERS AND THUNDERSTORMS, HIGHS ON TUESDAY WILL BE SLIGHTLY COOLER IN COMPARISON TO THE WEEKEND AND MONDAY, ALTHOUGH STILL AROUND 5 DEGREES ABOVE NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... 12Z GFS/00Z ECMWF HAVE DIFFERENT DEPICTIONS IN THE EXTENDED...AND THEREFORE CONFIDENCE IS BELOW AVERAGE. BOTH MODELS SHOW GENERAL AGREEMENT THAT THERE WILL BE A NEARLY STATIONARY UPPER LEVEL LOW/TROUGH NEAR THE CAROLINAS. HOWEVER...MULTIPLE RUNS OF THE GFS KEEPS THIS FEATURE OVER THE ATLANTIC OCEAN WITH JUST SOME CLOUDS LOCALLY...WHILE THE ECMWF HAS THE FEATURE INLAND ALONG THE EAST COAST AND SPREADS RAIN AS FAR WEST AS WEST VIRGINIA AND EASTERN OHIO. WITH NAEFS AND ECMWF ENSEMBLE KEEPING THE PATTERN A LITTLE DRIER...HAVE ALSO STUCK WITH A DRIER FORECAST. IF THIS HOLDS...AND THE GFS FORECAST VERIFIES...THIS PERIOD WILL BE QUITE WARM. GFS BIAS-CORRECTED GRIDS AND NAEFS METEOGRAMS SUGGEST THAT 90 DEGREES IS NOT OUT OF THE QUESTION FOR THE START OF THE MEMORIAL DAY WEEKEND. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... HIGH PRESSURE WILL KEEP SKIES MOSTLY CLEAR AND WINDS BELOW 10 KTS FOR NEXT 24 HOURS. THE ONLY CLOUDS THAT ARE EXPECTED WILL BE WITH BLOWOFF FROM POSSIBLE TROPICAL SYSTEM OFF CAROLINAS. .OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY... SUNDAY NIGHT SHOULD REMAIN DRY BEFORE COLD FRONT APPROACHES FROM THE WEST ON MONDAY. CONVECTION WILL ALSO INCREASE FROM THE EAST. SLOW MOVING FRONT WILL BRING A CONTINUED CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. PRECIPITATION SHOULD THEN SHIFT EAST OF THE AREA BY WEDNESDAY NIGHT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
159 PM EDT SAT MAY 19 2012 .SYNOPSIS... HIGH PRESSURE WILL ALLOW FOR DRY AND UNSEASONABLY WARM WEATHER TO CONTINUE INTO EARLY MONDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL RETURN AS A LOW PULLS MOISTURE INTO THE AREA FROM THE SOUTHEAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST. && .NEAR TERM /THROUGH SUNDAY/... 18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED WITH MINOR CHANGES TO THE GOING FORECAST TO ADJUST SKY GRIDS AS THIN CIRRUS CONTINUES TO FILTER INTO THE AREA WELL AHEAD OF A LOW CENTER OFF THE CAROLINA COAST. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE EXTENDING FROM THE THE OHIO VALLEY INTO NEW ENGLAND WITH ITS ASSOCIATED WEAK ANTI-CYCLONIC FLOW CENTERED ACROSS THE OHIO VALLEY. MEANWHILE, A CLOSED LOW IS LOCATED OFF THE CAROLINA COAST. AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE IS CENTERED ACROSS THE NORTHEAST, EXTENDING SOUTHWESTWARD INTO THE REGION. THE RIDGE WILL SHIFT FURTHER NORTHEAST TONIGHT AND TOMORROW, ALLOWING FOR DRY AND UNSEASONABLY WARM WEATHER TO CONTINUE. SKIES WILL BE MOSTLY CLEAR THROUGH THIS PERIOD, ASIDE FROM SOME HIGH CIRRUS SPILLING INTO THE AREA AHEAD OF THE LOW TO THE SOUTHEAST. DESPITE TEMPS IN THE LOW TO MID 80S FOR HIGHS, DRY AIR IN PLACE ALONG WITH NEAR CALM WINDS AND MOSTLY CLEAR SKIES OVERNIGHT WILL ALLOW FOR ANOTHER NIGHT OF DECENT RADIATIONAL COOLING. THUS, LOWS ARE A MAV/MET BLEND, DROPPING TO NEAR NORMAL SEASONAL VALUES, IN THE LOW TO MID 50S ACROSS THE AREA. THE GFS INDICATES 850 TEMPS AROUND 15C TOMORROW. THIS WILL CONTRIBUTE TO YET ANOTHER DAY WITH HIGHS 10-15 DEGREES ABOVE NORMAL, RANGING FROM THE MID 80S ACROSS THE LOWLANDS TO THE MID 70S ACROSS THE EASTERN RIDGES. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... MODELS CONTINUE TO STRUGGLE WITH THE INTERACTION OF THE CUTOFF LOW OVER THE SOUTHEAST THROUGH AND THE TROUGH ACROSS THE UPPER MIDWEST. AT THIS POINT...THE 500HPA RIDGE SHOULD BEGIN TO PINCH OFF SUNDAY NIGHT AND AS IT TRANSFERS TO THE COAST THE UPSTREAM TROUGH ACTUALLY HELPS TO BRING THE CUTOFF LOW FURTHER WEST. THE ECMWF/GFS CONTINUE TO BE FAVORED THROUGH THIS TIME PERIOD AS THE NAM KEEPS THE LOW SLIGHTLY FARTHER SOUTH. GRADUALLY INCREASE PRECIP CHANCES FROM BOTH THE EAST AND WEST MONDAY AS WE ARE SQUEEZED BETWEEN THE COLD FRONT AND THE CUTOFF LOW AND MAINTAIN THOSE CHANCES THROUGH TUESDAY. TEMPERATURES SHOULD CONTINUE TO REMAIN 10 DEGREES ABOVE NORMAL SUNDAY AND 5-10 DEGREES ABOVE NORMAL MONDAY DESPITE INCREASING CLOUD COVER AND PRECIPITATION CHANCES. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... MODELS CONTINUE TO DISAGREE SOMEWHAT WITH REGARD TO TIMING OF THE FRONT APPROACHING FROM THE WEST AND ON THE EXTENT OF RETROGRESSION OF EAST COAST LOW EARLY NEXT WEEK. STAYED CLOSE TO HPC GUIDANCE WHICH STILL LEANS TOWARD FASTER GFS TIMING WITH THE FRONT AND PUSHES THE MAIN AREA OF PRECIPITATION EAST OF THE REGION BY WEDNESDAY NIGHT. A WEAK SURFACE RIDGE SHOULD PROVIDE GENERALLY DRY WEATHER FOR THURSDAY INTO FRIDAY FOR MUCH OF THE FORECAST AREA. MOIST SOUTHEAST FLOW FROM THE ATLANTIC DEPICTED BY THE ECMWF COULD MAINTAIN SCATTERED PRECIPITATION OVER THE RIDGES ON THURSDAY NIGHT AND FRIDAY. TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR CONDITIONS AND LIGHT EAST WINDS WILL PREVAIL THROUGH THE TAF PERIOD AS A SURFACE RIDGE HOLDS ALONG THE APPALACHIANS. .OUTLOOK...SUNDAY THROUGH WEDNESDAY... THE SURFACE RIDGE WILL MAINTAIN VFR WEATHER THROUGH SUNDAY NIGHT. A FRONT WILL APPROACH FROM THE WEST LATE MONDAY WHILE A LOW PRESSURE SYSTEM MOVES INLAND FROM THE CAROLINA COAST. MOISTURE WILL INCREASE ACROSS THE REGION BY EARLY MONDAY ALONG WITH THE POTENTIAL FOR RESTRICTIONS IN SHOWERS AND THUNDERSTORMS. SCATTERED PRECIPITATION SHOULD PERSIST THROUGH WEDNESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 PM EDT SAT MAY 19 2012 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 508 AM EDT SAT MAY 19 2012 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE GREAT LAKES DOWNSTREAM OF TROF IN THE ROCKIES. CWA IS IN THE WARM SECTOR E OF SFC-H85 TROF/COLD FNT AND S OF WARM FNT OVER NRN LK SUP/ ADJOINING ONTARIO. WITH DRYNESS SHOWN ON LOCAL 00Z RAOBS /H925 DEWPT DEPRESSIONS ARE 15 TO 25C ON THE MPX/GRB RAOBS AND THE H85 DEWPT DEPRESSION AT GRB WAS 49C/...SKIES ARE MOCLR OVER UPR MI. DESPITE THE CLEAR SKIES/DRY AIR AND LOCAL DECOUPLING... TEMPS ARE WELL ABV NORMAL WITH STEADY SW FLOW AT H925 LIMITING THE OVERALL DIURNAL TEMP DROP. SOME SHRA/TS DID IMPACT MUCH OF MN THIS PAST EVNG DESPITE FAIRLY DRY AIR.AS SHRTWV LIFTED NNEWD WELL E OF THE MAIN TROF TO THE W...BUT THESE ARE TENDING TO WEAKEN AND STAY W OF EVEN LK SUP. MORE WIDESPREAD SHRA/TS ARE LOCATED IN THE PLAINS CLOSER TO H85 COLD FNT. MAIN FCST CONCERNS TDAY ARE FOCUSED ON FIRE WX. FOCUS FOR TNGT THRU SUN SHIFTS TO SHRA/TS CHCS ASSOCIATED WITH SLOWLY APRCHG UPR TROF/ COLD FNT. TDAY...CWA WL REMAIN UNDER WARM SW FLOW AS COLD FNT TO THE W SLIDES EWD THRU MN. ALTHOUGH H85 TEMPS ARE FCST TO AVG ABOUT A DEGREE LOWER THAN YDAY...VERY DEEP MIXING SHOWN ON THE 00Z MPX RAOB SHOULD SUPPORT MAX TEMPS NEARLY SIMILAR TO WHAT OCCURRED ON FRI PER UPSTREAM OBSVD SFC HI TEMPS...WITH SOME PLACES OVER THE W HALF SEEING THE MERCURY REACH 90. GOING FCST SHOWING THESE HIER TEMPS IN THE DOWNSLOPE AREAS FM ONTONAGON TO BARAGA LOOK ON TRACK. AREAS OVER THE E HALF SHOULD SEE SOME MODERATION OFF LK MI. SOME LK MODERATION MAY SLIP A BIT FARTHER W INTO THE CNTRL IF FCST BACKING WINDS TO MORE DUE S DRAGS THE LK MI MODERATION INTO THAT AREA. SEE FIRE WX SECTION BLO FOR A DISCUSSION OF FIRE WX CONCERNS. TNGT...WITH BLDG UPR RDG FCST OVER THE ERN GRT LKS...OPTED TO FOLLOW THE SOMEWHAT SLOWER 12Z ECMWF/00Z CNDN MODELS FOR THE TIMING OF THE COLD FNT...ESPECIALLY SINCE A SHRTWV LIFTING NEWD OUT OF THE ROCKIES WL INDUCE A LOW PRES TO DVLP ON THIS BNDRY OVER THE PLAINS TDAY. THIS LO IS FCST TO MOVE INTO MN BY 12Z SUN. THE 00Z NAM HAS TRENDED IN THIS DIRECTION AS WELL. IN FACT...THE 12Z ECMWF/0Z CNDN MODELS INDICATE THE BULK OF ANY PCPN WL BE ON THE COLD SIDE OF THE FNT AND STAY W OF IWD THRU 12Z. THIS FCST IS REASONABLE CONSIDERING THE DRYNESS OF THE WARM SECTOR AIRMASS AND FCST DEEP LYR QVECTOR CNVGC BEING FOCUSED UNDER THE SHARPER DPVA ASSOCIATED WITH THE SHRTWV ON THE COLD SIDE OF THE FNT IN MN EVEN AS LATE AS 12Z SUN. STEADY SW FLOW IN THE WARM SECTOR SHOULD ONCE AGAIN LIMIT THE DIURNAL FALL OF TEMP...SO MINS WL BE WELL ABV NORMAL AGAIN. SUN...SINCE THE FAVORED 12Z ECMWF/00Z CNDN MODELS SHOW BULK OF DEEP LYR QVECTOR CNVGC SHIFTING NEWD THRU WRN LK SUP TOWARD ONTARIO... SUSPECT THE HIER POPS WL BE OVER THE NW CWA...WITH PCPN TENDING TO DIMINISH AS THE FNT SHIFTS TO THE E INTO THE CENTRAL CWA BY LATE AFTN. HOWEVER...DAYTIME HEATING MAY OFFSET THE LOSS OF BEST DYNAMICS...ESPECIALLY SINCE THE CNDN MODEL SHOWS HIER H85 DWPTS UP TO 12C SURGING NEWD RIGHT ALONG THE FNT. HOWEVER...THIS SOMEWHAT HIER MSTR IS STILL RELATIVELY LO COMPARED TO H85 TEMPS FCST ARND 16C. SO THE LLVLS WL STILL BE RATHER DRY PER THE MODEL FCST SDNGS...LIMITING DESTABILIZATION. OPTED TO GO WITH LIKELY POPS OVER THE NW CWA...DIMINISHING TO CHC FARTHER TO THE E. RAISED FCST HI TEMPS WELL INTO THE 80S OVER THE E AND CNTRL AWAY FM LK MI MODERATION TO ACCOUNT FOR SLOWER ARRIVAL OF COLD FNT. SUN NGT...EXPECT COLD FNT TO PUSH THRU THE REST OF THE CWA ACCOMPANIED BY CHC POPS AS MAIN SHRTWV/SHARPEST DEEP LYR QVECTOR CNVGC EXITS TO THE NE AND ANY HELP FM DIURNAL HEATING WANES. SINCE GUIDANCE HINTS AT THE ARPCH OF A SECOND SHRTWV FM MN...MAINTAINED THE CHC POPS HANGING WELL BACK BEHIND THE COLD FNT AS HINTED AT BY 00Z NAM/12Z ECWMF AND SHOWN IN PREVIOUS FCST DESPITE MID LVL DRYING IN THE WAKE OF THE INITIAL DISTURBANCE. IF THIS TRAILING SHRTWV IS WEAKER...THE DRYING BEHIND THE FIRST STRONGER SHRTWV MAY END THE POPS FASTER THAN FCST AS FCST BY THE 00Z CNDN. THE ARRIVAL OF H85 TEMPS AOB 5C OVER THE W BY 12Z MON WL BRING A RETURN OF MORE SEASONABLE TEMPS. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 508 AM EDT SAT MAY 19 2012 A SLOWLY TRANSITIONING WX PATTERN...WITH MUCH OF THE PERIOD CONTINUING TO BE DOMINATED BY SOUTHERLY WINDS. INITIALLY WE WILL HAVE THE EXITING COLD FRONT TO OUR EAST...AND HIGH PRESSURE PUSHING IN FROM THE CENTRAL AND N PLAINS. AS A RESULT...EXPECT TEMPS TO BE 10 TO 15 DEGREES COOLER THAN SUNDAY. 850MB TEMPS WILL BE 4-5C. WITH THE COOL TEMPS WILL COME DRY AIR...WITH LOWER DEWPOINTS MONDAY AFTERNOON INTO THE MID 30S OVER THE W HALF. WOULD NOT BE COMPLETELY SHOCKED TO SEE VALUES CLOSER TO 30F...WHICH WOULD GIVE RH VALUES NEAR 25 PERCENT. THE SFC HIGH WILL BE DIRECTLY OVERHEAD TUESDAY MORNING...BEFORE SLIDING E. EXPECT THE RETURN OF S WINDS...AND A LITTLE BETTER MOISTURE. WE WILL SEE STRONGER SOUTHERLY WINDS RETURN BRIEFLY WEDNESDAY AFTERNOON. ADJUSTED MAX TEMPS UP OVER THE TRADITIONAL DOWNSLOPE AREAS NEAR LAKE SUPERIOR...WITH 850MB TEMPS RISING TO 11 TO 15C WITH THE COOLEST VALUES EAST. WENT ABOVE CONSENSUS FOR HIGH TEMPS THURSDAY...ONCE AGAIN WITH A MORE SIGNIFICANT INCREASE TO DOWNSLOPE AREAS. 850MB WINDS PEG OUT BETWEEN 45 AND 60KTS...AND TEMPS JUMP UP TO 15-18C. THE 19/00Z GFS IS ONE OF THE COOLEST SOLUTIONS. WILL BE INTERESTING HOW THE END OF THE WORK WEEK PANS OUT...AND IF THE FRONTAL BOUNDARY SETS UP AND STALLS OVER THE W CWA LIKE THE 19/00Z ECMWF...OR BLOWS THROUGH OUR AREA THURSDAY NIGHT BEFORE STALLING OVER LOWER MI FRIDAY INTO SATURDAY. WILL NOT GET TOO FANCY WITH THE FORECAST THAT FAR OUT...AND WILL KEEP THE SLIGHT CHANCE/LOW CHANCE POPS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 133 PM EDT SAT MAY 19 2012 EXPECT VFR CONDITIONS FOR MOST OF THE FORECAST PERIOD AT THE TAF SITES. A COLD FRONT APPROACHING THE AREA LATE TONIGHT INTO TOMORROW WILL BRING INCREASING CLOUD COVER AND A CHANCE OF SHOWERS AND POSSIBLY A THUNDERSTORM TO KIWD/KCMX. STILL SOME UNCERTAINTY ON INTENSITY OF THE SHOWERS...SO HAVE LEFT VSBYS AT VFR. ONE FINAL ITEM OF NOTE IS THE POTENTIAL FOR CIGS TO DROP AT KIWD/KCMX LATE IN THE PERIOD IF FOG DEVELOPS OVER WRN LK SUPERIOR LATE TONIGHT INTO TOMORROW MORNING. WINDS TURNING TO THE WNW BEHIND THE FRONT WOULD PUSH THE FOG ONSHORE AND EFFECT BOTH SITES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT SAT MAY 19 2012 WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD. LOW PRESSURE STRETCHING FROM SOUTHWESTERN QUEBEC TO NEBRASKA WILL SHIFT NORTHEASTWARD...FILLING SLIGHTLY AS IT CROSSES LAKE SUPERIOR SUNDAY INTO SUNDAY EVENING. BEHIND THIS FEATURE...HIGH PRESSURE WILL BUILD ACROSS THE UPPER GREAT LAKES MONDAY AND MONDAY NIGHT. EXPECT THE HIGH TO SLOWLY EXIT NORTHEASTWARD THROUGH MID WEEK...IN RESPONSE TO A STRONGER LOW NEARING FROM SOUTH CENTRAL CANADA THROUGH THE CENTRAL PLAINS. EXPECT THE LOW TO OUR WEST TO MOVE OVER ONTARIO ON THURSDAY...BEFORE EDGING ACROSS LAKE SUPERIOR THURSDAY NIGHT. && .FIRE WEATHER... ISSUED AT 508 AM EDT SAT MAY 19 2012 AFTER AN OVERNGT OF RELATIVELY POOR RH RECOVERY...EXPECT ANOTHER DAY OF AT LEAST NEAR CRITICAL FIRE WX PARAMETERS. MAX TEMPS THIS AFTN WILL BE SIMILAR TO WHAT WAS OBSVD YDAY...BUT DEEPER MIXING SHOWN ESPECIALLY ON THE 00Z MPX RAOB MIGHT TAP INTO LOWER DEWPTS. IN FACT...SFC DEWPTS WERE AS LO AS 35 TO 45 UPSTREAM YDAY AFTN IN WRN WI/SRN MN. BLENDED MIXED DEWPT TOOL VALUES WITH THE PREVIOUS FCST DEWPTS TO COME UP WITH READINGS DIPPING AS LO AS 43 OR SO. WITH WINDS ALOFT TDAY ALSO NEARLY SIMILAR TO YDAY AND DEEP MIXING RELATED TO DAYTIME HEATING... SUSTAINED WINDS AS HI AS 10 TO 20 MPH WITH GUSTS TO 30 MPH AT THE MORE EXPOSED LOCATIONS ARE LIKELY. OPTED TO ISSUE RFW FOR AN ARK FROM IWD/ONTONAGON TO BARAGA/MQT COUNTIES...AREAS THAT SAW THE POOREST RH RECOVERY EARLY THIS MRNG AND WHERE STRONGER WINDS/HIER DAYTIME HI TEMPS ARE MOST LIKELY. WL ISSUE RFD FOR THE OTHER COUNTIES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... RED FLAG WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR MIZ002-004-005-009-084. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...SRF MARINE...KF FIRE WEATHER...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1255 PM CDT SAT MAY 19 2012 .UPDATE... UPDATED FOR AVIATION DISCUSSION BELOW. && .DISCUSSION... /ISSUED 429 AM CDT SAT MAY 19 2012/ WATER VAPOR IMAGERY AND RUC H5 ANALYSIS SHOWS A RATHER EXPANSIVE RIDGE IN PLACE THIS MORNING EAST OF THE MS RIVER...WITH A RATHER COMPLEX TROUGH MOVING INTO THE HIGH PLAINS...WITH SEVERAL SHORTWAVES EMBEDDED WITHIN IT. THE TWO PRIMARY ONES ARE CURRENTLY OVER ERN SODAK AND MOVING FROM CO UP INTO SRN NEB. AT THE SFC...A COUPLE OF AREAS OF LOW PRESSURE COULD BE FOUND OVER FAR NW ONTARIO...WITH ANOTHER NEAR THE CO/NEB/KS BORDER. A COLD FRONT IS ANALYZED BETWEEN THESE LOWS ACROSS THE ERN DAKOTAS. FOR THE H5 PATTERN...THE RIDGING NOW MOVING ON TO THE HIGH PLAINS WILL SLOWLY BEAT DOWN THE ERN RIDGE...WITH THE TROUGH CURRENTLY COMING OUT OF CO WORKING ACROSS THE MPX CWA SUN INTO SUN EVENING. FOR MON/TUE...RIDGING WILL BE BUILDING IN ACROSS CENTRAL NOAM AS A SIGNIFICANT TROUGH DIGS INTO THE PAC NW. AS WE HEAD THROUGH THE SECOND HALF OF NEXT WEEK...THIS PATTERN LOOKS BECOME QUITE AMPLIFIED...AS VERY HIGH HEIGHTS SET UP INTO THE GREAT LAKES...WITH A QUASI-STATIONARY DEEP TROUGH TAKING HOLD ACROSS THE NRN ROCKIES...SETTING THE UPPER MIDWEST UP INTO A POTENTIAL ACTIVE PATTERN. AT THE SFC...THE COLD FRONT WILL WORK INTO WRN MN BY THIS AFTERNOON...AND CLEAR THE MPX WI COUNTIES SUN AFTERNOON. THE LOW CENTER CURRENTLY NEAR THE CO/NEB/KS WILL TRACK ACROSS SOUTH CENTRAL MN INTO THE WRN TIP OF THE U.P. OF MICH SAT NIGHT/SUN. HIGH PRESSURE WILL THEN SLIDE ACROSS THE AREA MON/TUE...BEFORE LEE SIDE TROUGHING REESTABLISHES ITSELF OVER THE NRN HIGH PLAINS WED. NEXT FRONT STILL ON TAP TO MOVE INTO MN WED NIGHT...AND WITH UPPER RIDGE AMPLIFYING OVER THE GREAT LAKES THE LATTER HALF OF NEXT WEEK...THIS FRONT STILL LOOKS TO STALL OUT THEN MEANDER AROUND THE UPPER MS VALLEY INTO THE HOLIDAY WEEKEND. THIS MORNING...STRONG WAA OUT AHEAD OF THE ERN SODAK SHORTWAVE HAS RESULTED IN THE DEVELOPMENT OF AN AREA OF TSRA OVER WRN MN...RADAR TRENDS MATCH WELL WITH THE IDEA THE RUC IS SHOWING...WITH THIS WAA AND ASSOCIATED ACTIVITY BASICALLY GOING DUE NORTH INTO NW MN. DO EXPECT CONDITIONS TO BE FAIRLY QUIET THROUGH THE MORNING...WITH THE SODAK SHORTWAVE AND COLD FRONT EXPECTED TO REMAIN WEST OF THE AREA. ONE CAVEAT IS THE LLJ AND STRONG MOISTURE TRANSPORT IN PLACE ACROSS THE WEST. THIS MAY KEEP SCT SHRA/TSRA ACTIVITY GOING THROUGH THE MORNING OUT WEST...BUT DID NOT PLAY THIS IDEA UP TO MUCH IN THE GRIDS. INSTEAD...WAITED UNTIL THE AFTERNOON TO REALLY GET POPS GOING. BY THEN THE COLD FRONT WILL BE WORKING INTO WRN MN AS UPPER ENERGY BEGINS TO WORK IN OVERHEAD. LOOKING AT HIRES REFLECTIVITY FORECASTS...SEEMS TO BE GOOD AGREEMENT WITH STORMS INITIATING NEAR A RWF TO LONG PRAIRIE LINE BETWEEN 20 AND 22Z...WITH ACTIVITY WORKING EAST TOWARD THE I-35 CORRIDOR SHORTLY AFTER 00Z. FORECAST SOUNDINGS AGAIN SHOW NICE INVERTED-V STRUCTURE THIS AFTERNOON...WITH MLCAPE AGAIN PUSHING UP TO AROUND 1500 J/KG. IN ADDITION...UNLIKE YESTERDAY...BULK SHEAR WILL BE IN THE 30-40 KT RANGE...INDICATING SOME BETTER ORGANIZATION IN CONVECTION IS POSSIBLE. GIVEN LESS FAVORABLE CONDITIONS MANAGED A FEW 60-70 MPH WIND GUSTS AND GOLF BALL SIZE HAIL FRIDAY...DO NOT SEE WHY WE DO NOT HAVE A SIMILAR THREAT FOR SEVERE WEATHER TODAY. IF ANYTHING...WOULD SUSPECT THE WIND THREAT IS A BIT HIGHER AS BETTER SHEAR AND FAVORABLE CONDITIONS FOR COLD POOL GENERATION MAY SUPPORT THE DEVELOPMENT OF ORGANIZED LINE SEGMENTS. BESIDE THE PRECIP...SHOULD BE ANOTHER WARM DAY...THOUGH NOT EXPECTING WIDESPREAD 90S LIKE FRIDAY. TWO LIMITING FACTORS FOR HIGHS TODAY WILL BE MORE CLOUD COVER AND ABOUT A 4 DEG C DROP IN H85 TEMPS. WITH THAT SAID...GUIDANCE HAS HAD A PRETTY STRONG COLD BIAS IN THIS HEAT WAVE...SO CONTINUED TO RUN WITH HIGHS A BIT HIGHER THAN WHAT MOST GUIDANCE WOULD SUGGEST. FOR TONIGHT...WITH THE ARRIVAL OF THE UPPER TROUGH AND ATTENDANT SFC LOW...WE CONTINUE TO SEE A STRONG SIGNAL FOR THE FORMATION OF A DEFORMATION BAND OF PRECIP JUST TO THE WEST OF THE SFC LOW TRACK. BLENDED THE ECMWF/GEM/SREF FOR PRECIP TONIGHT...WITH HEAVIEST BAND OF PRECIP EXPECTED TO SETUP BETWEEN THE WRN TWIN CITIES METRO AND MARSHALL/ALEXANDRIA. WITH THE SFC LOW COMING THROUGH...THIS REALLY SLOWS DOWN THE PRECIP...AND CONTINUED TO LEAN TIMING OF POPS ON SUN CLOSE TO THE ECMWF. THE ECMWF ALONG THE NAM/SREF WOULD INDICATE SUNDAY BEING CLOUDY/RAINY FOR MOST OF THE DAY SUNDAY ACROSS MOST OF THE MN MPX AREA...WITH HIGHS LIKELY NOT LEAVING THE LOWER 60S. FURTHER EAST...THE COLD FRONT/LOW SHOULD BE NEAR AN EAU/LADYSMITH LINE BY 18Z...SO SEVERE THREAT CERTAINLY LOOKS BETTER EAST...THOUGH A MARGINAL TREAT FOR SEVERE WEATHER CAN NOT BE RULED OUT IN THE FAR EAST. MON THROUGH WED STILL LOOK DRY AS HIGH PRESSURE SLIDES ACROSS THE AREA. BIGGEST THING TO WATCH WILL BE LOWS MONDAY MORNING. IF HIGHS ONLY TOP OUT AROUND 60 IN CENTRAL MN...WE COULD SEE LOWS MONDAY MORNING MAKE A RUN AT THE UPPER 30S AS HIGH PRESSURES MOVES IN AND SKIES CLEAR OUT. OTHER THAN THAT...ITS OFF TO WAITING FOR THE NEXT FRONT WEDNESDAY NIGHT. THE ONLY SIGNIFICANT CHANGE NOTED IN THE MODELS WITH THIS FRONT IS THE 19.00 ECMWF BASICALLY HALTS ITS EWRD PROGRESSION ACROSS WRN MN...WITH THE RAIN NOT MAKING IT TO ERN AREAS. AT ANY RATE...CONTINUED TO MENTION HIGH CHANCE/LIKELY POPS...ESPECIALLY WEST WED NIGHT. AFTER THAT...THE QUESTION BECOMES WHERE DOES THE FRONT SET UP. WHERE EVER IT DOES SETUP...NORTH OF THE BOUNDARY THROUGH THE WEEKEND IS LOOKING LIKE IT COULD BE A BREEDING GROUND FOR SOME ACTIVE WEATHER...CERTAINLY SOMETHING TO KEEP A CLOSE EYE ON AS WE HEAD INTO THE BUSY HOLIDAY WEEKEND. && .AVIATION.../18Z TAF ISSUANCE/ THE MAIN AVIATION CONCERNS REMAIN...TIMING OF THUNDER THIS AFTERNOON/TONIGHT AND DEVELOPMENT OF MVFR/IFR CEILINGS. COLD FRONT PUSHING INTO WEST CENTRAL MINNESOTA AT THIS TIME...MOVED THROUGH KAXN AS OF 18Z. THIS SHOULD DISSIPATE ANY SIGNIFICANT THREAT OF THUNDER THERE THIS AFTERNOON. STILL INCLUDED TEMPO FOR A FEW HOURS LATE THE AFTERNOON...AS IT REMAINS CLOSE TO FRONT. REMAINDER OF AREA REMAINS TIMING ISSUE. INITIAL SHORT WAVE APPEARS TO BE MOVING THROUGH EAST CENTRAL MN AT THIS TIME. SHOWERS DISSIPATED PER MODEL TRENDS. STILL SOME THREAT OF REDEVELOPMENT EAST CENTRAL INTO WISCONSIN THIS AFTERNOON...WHERE HIGH INSTABILITY REMAINS. BETTER LIFT LOOKS TO ARRIVE LATER THIS AFTERNOON INTO THE EVENING WITH TEMPO THUNDER CONTINUED AHEAD OF THE FRONT TONIGHT. EXPECT MVFR CEILINGS INTO KAXN THIS AFTERNOON...AND THEN LOWERING TOWARD KSTC-KRWF TONIGHT WITH POST-FRONTAL RAIN. BEST CHANCE FOR IFR WILL BE THE KRWF TO KSTC AREA. THIS ALL SPREADS EAST OVERNIGHT/SUNDAY MORNING AND SHOULD END IN EASTERN MN THROUGH 14Z AND BEFORE 19Z IN WEST CENTRAL WISCONSIN. KMSP...WEAK WAVE MOVING ACROSS AREA EARLY...MAY INITIATE SHOWERS/STORMS INTO WESTERN WISCONSIN. OTHERWISE...WILL HAVE TO WAIT FOR COLD FRONT AS IT MOVES INTO THE AREA THIS EVENING. SHOULD MOVE THROUGH BY 06Z WITH THUNDER THREAT ENDING THEN. LINGERING SHRA AND MVFR CEILINGS BEHIND FRONT THROUGH ABOUT 12Z...BECOMING VFR AGAIN AFTER 15Z SUNDAY. OUTLOOK... SUN...SHRA AND SOME TSRA POSSIBLE IN THE MORNING FAR EASTERN MN AND WESTERN WI WITH MVFR/IFR POSSIBLE THEN IMPROVING CONDITIONS BY SUNDAY AFTERNOON ALL BUT WESTERN WISCONSIN. SUN NIGHT MON-TUE...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MPG/TDK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 PM CDT SAT MAY 19 2012 .SHORT TERM...TONIGHT THROUGH MONDAY NIGHT 353 PM CDT SAT MAY 19 2012 AT 3 PM...A COLD FRONT EXTENDED FROM INTERNATIONAL FALLS MINNESOTA TO SIOUX CITY IOWA. TEMPERATURES AHEAD OF THIS FRONT WERE IN THE 80S AND 90S. LA CROSSE WISCONSIN HAS REACHED 91 DEGREES. THIS WAS THEIR FIRST 90-DEGREE TEMPERATURE OF 2012. BEHIND THIS FRONT... TEMPERATURES WERE IN THE 50S AND 60S. WATER VAPOR AND PROFILERS INDICATE A WEAK SHORT WAVE TROUGH MOVING THROUGH EASTERN MINNESOTA AND WESTERN MINNESOTA. THIS SYSTEM IS PRODUCING SOME MID AND HIGH CLOUDS. IN ADDITION...A FEW ISOLATED SHOWERS NEAR RED WING. THE 19.18Z RAP AND 19.15Z HRRR CONTINUE TO SUGGEST THAT SCATTERED SHOWERS AND THUNDERSTORMS WILL REMAIN MAINLY NORTHWEST OF A PRESTON MINNESOTA TO NEILLSVILLE WISCONSIN LINE THIS EVENING. WHILE THE 0-6KM SHEAR IS INCREASING TO GREATER THAN 40 KNOTS BY 20.06Z...THE ML SHEAR IS RAPIDLY DECREASING. AS A RESULT...THE SEVERE WEATHER THREAT LOOKS VERY LOW. IF SOMETHING DID HAPPEN TO OCCUR...DAMAGING WINDS WOULD BE THE MAIN THREAT. THIS IS MAINLY A RESULT OF THE DRY AIR LOCATED BELOW THE CLOUD LAYER. FROM LATE TONIGHT THROUGH EARLY SUNDAY AFTERNOON...THE COLD FRONT WILL QUICKLY TRANSITION EASTWARD ACROSS THE FORECAST AREA. THIS IS VERY SIMILAR TO SPEED THAT WAS SHOWN IN THE 18.12Z GFS. WITH THIS TIMING...IT WILL BE MOVING THROUGH THE REGION DURING A TIME WHEN THE ML CAPES WILL BE AT THEIR MINIMUM /GENERALLY LESS THAN 1000 J/KG/. AS THE POSITIVELY TILTED TROUGH MOVES AWAY FROM THE AREA DURING THE MORNING...THE BEST MOISTURE TRANSPORT AND 0-6 KM SHEAR WILL MOVE NORTH AWAY FROM THE REGION. DUE TO THIS...THE AREAL COVERAGE LOOKS TO BE SCATTERED AT BEST AND THE SEVERE WEATHER THREAT LOOKS VERY SMALL. WITH A FASTER MOTION...THE AFTERNOON PRECIPITATION CHANCES WERE LOWERED ACROSS THE AREA. IN ADDITION...A CLEARING TREND IN THE CLOUDS WAS INTRODUCED. THIS LOOKS TO BE FAST ENOUGH THAT MOST AREAS WILL GET AN OPPORTUNITY TO SEE THE ANNULAR ECLIPSE ON SUNDAY EVENING. TEMPERATURES ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA WILL LIKELY REMAIN STEADY THROUGHOUT THE DAY... AND FALL DURING THE LATE MORNING AND AFTERNOON ACROSS WESTERN WISCONSIN. THIS NON-DIURNAL TREND WAS INTRODUCED BY THE MIDNIGHT CREW AND KEPT IN THE HOURLY TEMPERATURE GRIDS. ON MONDAY...THE 850 MB TEMPERATURES LOOKS TO BE ABOUT 2C WARMER THAN THE PREVIOUS MODELS. AS A RESULT...THE MAXIMUM TEMPERATURES WERE RAISED ANYWHERE FROM 3 TO 5F. .LONG TERM...TUESDAY THROUGH SATURDAY 353 PM CDT SAT MAY 19 2012 NEGATIVE OUTGOING LONG WAVE RADIATION ACROSS THE WESTERN EQUATORIAL PACIFIC CONTINUES TO SHOW A RETROGRESSION TOWARD INDONESIA. WITH SEA SURFACE TEMPERATURES IN THE EXCESS OF 26C...THIS AREA IS FAVORABLE TO SUPPORT STRONG TROPICAL FORCING. NORMALLY WHEN THE CONVECTION IS ROBUST IN THIS AREA...A NEGATIVE PACIFIC NORTH-AMERICAN TELECONNECTION DEVELOPS /WESTERN TROUGH AND AN AMPLIFICATION OF AN EASTERN RIDGE/ ACROSS THE NORTH AMERICAN CONTINENT. AT THE SAME TIME...ANOTHER AREA OF NEGATIVE OUTGOING LONG WAVE RADIATION OVER THE EASTERN PACIFIC AND CENTRAL AMERICA IS EXPECTED TO MOVE SLOWLY EAST ACROSS THE ATLANTIC. AS THIS OCCURS...THE PERSISTENT TROUGH FROM THE MID-ATLANTIC SOUTH INTO THE YUCATAN PENINSULA WILL MOVE EAST INTO THE CARIBBEAN. OVERALL...THE 19.12Z MODELS SEEM TO HAVE A FAIRLY GOOD HANDLE ON THIS SITUATION. THEY ARE IN GOOD AGREEMENT THAT A COLD FRONT WILL MOVE SOUTHWARD INTO THE FORECAST AREA ON WEDNESDAY NIGHT...AND THEN IT BECOMES STATIONARY FOR THURSDAY AND THURSDAY NIGHT. THIS FRONT THEN MOVES NORTHWARD AS A WARM FRONT ON FRIDAY AS THE UPPER LEVEL RIDGE BUILDS. THIS FRONT WILL BE THE FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS. IT WAS THE CONSENSUS THAT THE OPERATIONAL GFS WAS TOO FAR SOUTH WITH THIS FRONT FROM FRIDAY INTO SATURDAY NIGHT...THEREFORE...THE FORECAST WAS TRENDED MORE TOWARD A BLEND OF THE ECMWF...GEM...AND A MAJORITY OF THE GFS SOLUTIONS. BY DOING THIS...THE PRECIPITATION CHANCES WERE REMOVED SOUTH OF THE INTERSTATE 90 CORRIDOR ON FRIDAY...AND ACROSS THE ENTIRE AREA FROM FRIDAY NIGHT INTO SATURDAY NIGHT. IN ADDITION...THE TEMPERATURES WERE RAISED FOR THIS TIME PERIOD. IF THE 19.12Z ECMWF IS CORRECT ON SATURDAY...TEMPERATURES COULD BE WELL INTO THE MID AND UPPER 90S. && .AVIATION...THIS AFTERNOON THROUGH SUNDAY 1230 PM CDT SAT MAY 19 2012 THE GENERALLY DRY LOWER LEVELS AND BREEZY SOUTH FLOW WILL KEEP CONDITIONS VFR AT BOTH KLSE AND KRST INTO THIS EVENING. WINDS WILL AGAIN BE 10-20KTS G20-30KTS THIS AFTERNOON...STRONGEST AT THE HIGHER TERRAIN/OPEN COUNTRY LOCATIONS...DIMINISHING QUICKLY THIS EVENING. MOISTURE WILL CONTINUE TO INCREASE TONIGHT...AHEAD OF A COLD FRONT DUE TO MOVE ACROSS THE AREA VERY LATE TONIGHT/MON MORNING. FRONT LOOKS TO MOVE ACROSS KRST AROUND 12Z AND KLSE AROUND 15Z...WITH WINDS SHIFTING TO THE NORTHWEST BEHIND IT. FRONT WILL ACT AS A FOCUS FOR SHRA/TSRA DEVELOPMENT AS IT MOVES ACROSS THE AREA LATE TONIGHT/ SUN MORNING. FORCING IS ON THE WEAK SIDE AND WITH CONVECTION EXPECTED TO BE SCT AS THE FRONT MOVES THRU...LEFT CIGS/VSBYS LATE TONIGHT/SUN MORNING VFR. MAY YET NEED A TEMPO OR PREVAILING PERIOD OF MVFR CIG/VSBY IN THE 09Z-15Z TIME-FRAME ONCE A MORE PRECISE TIMING OF THE FRONT CAN BE DETERMINED...OR IF IT APPEARS A BKN LINE OF CONVECTION WITH SOME STRONGER CELLS/TSRA WILL MOVE ACROSS THE TAF SITES. GIVE LOWER PROBABILITY OF THIS AT THIS TIME...LEFT MVFR MENTION CENTERED ON 12Z SUN OUT OF TAFS FOR NOW. DRIER NORTHWEST FLOW/HIGH PRESSURE WILL BUILD ACROSS THE AREA BEHIND THE FRONT... WITH GOOD VFR CONDITIONS EXPECTED BY LATE SUN MORNING/SUN AFTERNOON. && .ARX WATCHES/WARNINGS/ADVISORIES... 253 PM CDT SAT MAY 19 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
218 PM CDT SAT MAY 19 2012 .SHORT TERM...TONIGHT AND SUNDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD FRONT MOVING ACROSS THE NORTHERN MISSISSIPPI VALLEY AND HIGH PRESSURE CENTERED OVER THE APPALACHIANS. THE FRONT HAS BEEN MOSTLY INACTIVE SO FAR TODAY...THOUGH CONVECTION IS EXPECTED TO DEVELOP LATER THIS AFTERNOON OVER MINNESOTA. EARLIER SHOWERS AND STORMS ALONG A 305-310K MOISTURE GRADIENT HAVE FIZZLED...AND THE LEFT OVER CIRRUS SHIELD IS NOW ADVANCING INTO SW WISCONSIN. MOISTURE HAS BEEN INCREASING TODAY ACROSS THE AREA AS EVIDENT BY RISING SURFACE DEWPOINTS AND CU FORMATION. AS A SHORTWAVE OVER THE PLAINS PUSHES THE FRONT TO THE EAST OVER THE NEXT 24 HOURS...PRECIP AND SEVERE WEATHER CHANCES ARE THE MAIN FORECAST CONCERNS. TONIGHT...THE COLD FRONT EXTENDING FROM THE NORTHERN MISSISSIPPI VALLEY TO THE TEXAS PANHANDLE WILL SLOWLY MOVE EAST TONIGHT ACROSS EASTERN MINNESOTA AND NW WISCONSIN. BEHIND THE FRONT...RIGHT REAR QUAD OF THE JET...DPVA FROM THE SHORTWAVE...AND MID-LEVEL FGEN WILL PROVIDE A CHANCE OF PRECIP. HAVE CONFINED POPS OVERNIGHT TO CENTRAL AND NORTH-CENTRAL WISCONSIN IN CASE UPSTREAM PRECIP SNEAKS FARTHER EAST. NOT QUITE AS CONFIDENT ABOUT THIS EVENING HOWEVER. BAND OF PRECIP THAT STRETCHED FROM SOUTHERN MINNESOTA TO MISSOURI DISSIPATED BY MIDDAY...POSSIBLY AS A RESULT OF DIMINISHING MID-LEVEL CONVERGENCE. MOISTURE ADVECTION ON THE 305-310K ISENTROPIC SURFACES...WHICH WAS ALIGNED WITH THE BAND OF PRECIP...WILL MOVE ACROSS THE FORECAST AREA THIS EVENING...UNDER MID-LEVEL LAPSE RATES OF 7.5-8 C/KM. PROGGED SOUNDINGS INDICATE ELEVATED CAPES BETWEEN 500-1000 J/KG ARRIVE WITH THE MOISTURE ADVECTION. DO NOT SEE THE MID-LEVEL CONVERGENCE RETURNING...BUT DO NOT NECESSARILY TRUST GOING DRY EITHER. SINCE THE CLOUD BAND HAS BEEN THINNING AND CLOUD TOPS WARMING...HAVE DECIDED TO GO DRY THIS EVENING. SUNDAY...THE SHORTWAVE TROUGH WILL MOVE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN DURING THE MORNING...AND NORTHEAST WISCONSIN IN THE AFTERNOON. WITH FORCING BEHIND THE FRONT HOLDING TOGETHER...SHOULD SEE SCT SHOWERS AND THUNDERSTORMS MOVE EAST ACROSS THE FORECAST AREA THROUGH THE DAY. AN UPTICK OF SHOWERS AND STORMS WILL BE POSSIBLE IN THE AFTERNOON OVER NORTHEAST WISCONSIN WHERE THERE WILL BE HIGHER DAYTIME INSTABILITY. ASSUMING CLOUD COVER ALLOWS SUFFICIENT SUNSHINE...BOTH THE NAM AND GFS INDICATE 1000-1500 J/KG OF ML CAPE DEVELOPING BY MIDDAY...USING A SURFACE PARCEL OF 80F/61F. HIGHER WINDS ALOFT WILL EXIST BEHIND THE FRONT...BUT 0-6KM BULK SHEAR VALUES OF 25-30KT...WEAK CONVERGENCE ALONG THE FRONT...AND A FAIRLY UNIDIRECTIONAL WIND PROFILE SUGGESTS AN ISOLATED THREAT FOR SEVERE STORMS FOR WINDS AND HAIL AHEAD OF THE FRONT OVER NE WISCONSIN IN THE AFTERNOON. WILL KEEP A MENTION IN THE HWO. MORNING PRECIP WILL HOLD BACK TEMPS OVER CENTRAL AND NORTH-CENTRAL WISCONSIN IN THE MID 70S...WHILE NORTHEAST WISCONSIN COULD POSSIBLY REACH INTO THE LOWER TO MID 80S. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. TIMING OF PCPN CHANCES WILL BE THE PRIMARY CHALLENGE. MAIN CHANGE FOR SUNDAY EVENING IS THE FASTER FROPA AND BEST INSTABILITY IS DIMINISHING QUICKLY. WILL HANG ONTO A LINGERING CHANCE OF LIGHT CONVECTION FOR EASTERN WISCONSIN AS A MID LEVEL TROUGH WILL TRAIL THE SURFACE COLD FRONT SLIGHTLY. OTHERWISE HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN LATER SUNDAY NIGHT INTO WEDNESDAY. UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS BY THE MIDDLE OF THE NEXT WEEK. MEDIUM RANGE RUNS DIVERT ON LOCATION OF RETURN FLOW AHEAD OF A LOW PRESSURE SYSTEM OVER THE NORTHERN PLAINS. THE GFS ATTEMPTS TO DEVELOP SMALL CHC POPS OVER NORTH CENTRAL WISCONSIN CLOSER TO THE RETURN FLOW. MEDIUM RANGE MODEL RUNS DIVERT AFTER THURSDAY AND THEREFORE RESOLUTION OF THE FORECAST DIMINISHES. THE GFS BREAKS DOWN THE UPPER RIDGE FASTER FOR LATER NEXT WEEK AND DRAGS THE FRONTAL SYSTEM OVER FASTER VS THE SLOWER ECMWF. THE ECMWF ALSO BUILDS THE RIDGE AGAIN FOR A WARMER NEXT WEEKEND. BLEND OF THE RUNS PRODUCING WIDESPREAD SLIGHT CHANCES IN THE FORECAST DUE TO THIS TIMING ISSUE. THIS TIMING OF THE BREAKDOWN OF THE WARM RIDGE ALSO IMPACT THE TEMPERATURE MAX/MIN`S. && .AVIATION...VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH AT LEAST TONIGHT. THERE IS A VERY SMALL CHANCE OF A SHOWER THIS EVENING...BUT SCT PRECIP OVER THE PLAINS IS DIMINISHING AS IT MOVES NORTHEAST. SO NOT WORTH INCLUDING IN THE TAFS AT THIS TIME. GUSTY SOUTH-SOUTHWEST WINDS WILL CONTINUE THROUGH EARLY THIS EVENING BEFORE DIMINISHING. LLWS TO DEVELOP OVER CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT AS A COLD FRONT MOVES INTO THE STATE. THIS FRONT WILL HAVE POTENTIAL TO CREATE SHOWERS AND THUNDERSTORMS THROUGH THE DAY ON SUNDAY. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MPC/TDH