Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 04/01/12


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1026 AM MDT FRI MAR 30 2012 .UPDATE...WINDS HAVE INCREASED BEHIND WAVE THAN PASSED THROUGH THE AREA THIS MORNING. APPEARS SUBSIDENCE PLAYING A ROLE IN THE WINDS. 12Z NAM CROSS SECTIONS DID SHOW CROSS MOUNTAIN FLOW CLOSE TO 50 KTS AT MOUNTAIN TOP ALONG WITH WEAK MOUNTAIN WAVE THROUGH 18Z. SO QUESTION FOR TODAY IS HOW LONG THESE WINDS WILL CONTINUE. NAM CONTINUES SOME SORT OF WESTERLY...EVEN NORTHWEST...COMPONENT THROUGHOUT THE AFTERNOON...WHILE GFS AND RUC DEVELOP A CYCLONE IN THE DENVER AREA BY 19Z WITH MORE OF AN EASTERLY COMPONENT. WINDS ALOFT WILL REMAIN NORTHWEST THROUGH THE EVENING...THOUGH ON THE DECREASE AS RIDGE TRIES TO BUILD INTO THE REGION. FOR THIS UPDATE...WILL LEAN TOWARD THE NAM SOLUTION...THOUGH NOT AS STRONG WITH THE WINDS. FEEL THERE WILL BE ENOUGH MIXING TO OFFSET THE CYCLONE. SO ONLY CHANGE TO CURRENT GRIDS WILL BE TO TWEAK THE WINDS GRIDS A BIT INTO THE AFTERNOON. CURRENT THINKING IS THAT WINDS ACROSS THE AREA SHOULD BE DECREASING A BIT AND SPEEDS NOT EXPECTED TO MEET THE RED FLAG CRITERIA...BUT WILL CONTINUE TO MONITOR IF ANY HILITES ARE NEEDED. AS FOR THE FIRE AREA...STILL THINKING DIURNAL UPSLOPE CONDITIONS SHOULD PREVAIL TODAY. && .AVIATION...WILL MAINTAIN WSW WINDS AT DIA AND BJC THROUGH ABOUT 19Z THEN MORE OF A NORTHWEST DIRECTION...WITH SPEEDS IN THE 12-18 KT RANGE. STILL SOME CHANCE OF A DENVER CYCLONE DEVELOPING...AS SHOWN BY THE GFS AND RUC SOLUTIONS...WITH MORE OF AN EASTERLY COMPONENT. WILL HOLD OFF ON THE EASTERLY DIRECTION FOR NOW. OTHERWISE...REST OF TAF TRENDS...INCLUDING APA TRENDS...SEEM ON TRACK. && .PREV DISCUSSION... /ISSUED 418 AM MDT FRI MAR 30 2012/ ..CORRECTION FOR A FEW TYPOS AND MISSING WORDS SHORT TERM...A WEAK SHORT WAVE CURRENTLY OVER EASTERN COLORADO WILL CONTINUE TO PUSH EAST THIS MORNING. THIS BROUGHT SOME MID AND HIGH CLOUDS OVERNIGHT. DOWNWARD MOTION AND DRIER AIR BEHIND IT WILL BRING MOSTLY SUNNY SKIES THIS MORNING. MODELS SHOWING HIGH CLOUDS INCREASING LATE THIS AFTERNOON AND EARLY EVENING. THERE WILL BE SOME RIDGING IN THE FLOW ALOFT TODAY. THE AIRMASS WILL WARM 3-6 DEGREES FAHRENHEIT FROM YESTERDAY...RESULTING IN HIGHS IN THE MID TO UPPER 70S TODAY ACROSS NORTHEAST COLORADO. FAR NORTHEAST COLORADO WILL SEE BREEZY CONDITIONS TODAY. WINDS AND HUMIDITY WILL BE CLOSE TO RED FLAG WARNING CRITERIA TODAY...BUT DO NOT EXPECT THEM TO MEET CRITERIA FOR THE REQUIRED TIME...3 HOURS. AREAS WEST OF THE CONTINENTAL DIVIDE WILL ALSO SEE BREEZY CONDITIONS WITH GUSTS TO 25 MPH. LONG TERM...A POTPOURRI OF WEATHER TO CONTEND WITH IN THE EXTENDED PERIOD OF THE FORECAST. WE/LL BEGIN WITH THE UNSEASONABLY WARM IF NOT RECORD BREAKING TEMPERATURES ANTICIPATED ON SATURDAY AND NOW IT LOOKS LIKE SUNDAY...TOO. FOR SATURDAY...STATE WILL BE UNDERNEATH AN UPPER RIDGE EXTENDING FM MEXICO TO THE CANADIAN BORDER. 700 MB TEMPERATURES ALONG THE FRONT RANGE PROGGED TO BE IN THE 10-12C RANGE WHICH WHEN BROUGHT DOWN TO THE SFC DRY ADIABATICALLY EQUATES TO HIGH TEMPERATURES IN THE LOWER/MID 80S ON THE PLAINS. RECORD HIGH AT DENVER ON SAT IS 80F. WOULDN/T THINK WE WOULD HAVE ANY PROBLEM BREAKING THAT AS LONG AS THE HIGH LEVEL CLOUD COVER EXPECTED THAT DAY DOESN/T BECOME TOO THICK. IT EARLIER LOOKED AS THOUGH WE COULD SEE RED FLAG WARNING CONDITIONS ON SATURDAY...MAINLY REFERRING TO STG AND GUSTY SOUTH-SOUTHWEST WINDS. NO LONGER APPEARS TO BE THE CASE WITH THE SLOWER EASTWARD PROGRESS OF THE UPPER RIDGE... WINDS SFC AND ALOFT NOT EXPECTED TO BE ALL THAT STRONG. HIGH COUNTRY COULD SEE QUITE OF BIT OF SNOW MELT EVEN AT THE HIGHEST ELEVATIONS...BUT HEAVY SNOWMELT RUNOFF IS NOT LIKELY TO BE A PROBLEM. BY SUNDAY..MODELS SHOW THE UPPER RIDGE MOVING OVER THE GREAT PLAINS CAUSING THE FLOW ALOFT TO GO SOUTHWESTERLY. WINDS ALOFT ARE FCST TO STRENGTHEN THRU THE DAY. COULD SEE THIS MOMENTUM MIXING DOWN TO THE SFC ON THE PLAINS BY AFTERNOON WITH GUSTS IN THE 20-30 MPH RANGE ON THE PALMER DIVIDE AND OUT ACROSS LINCOLN AND WASHINGTON COUNTIES. WILL NEED TO MONITOR THIS TO SEE HOW THIS DEVELOPS AS A FIRE WEATHER WATCH MAY BE NECESSARY OUT THERE. THEN ALL THIS HEAT AND DRYNESS COMES TO AN END SUNDAY NIGHT WITH A STRONG COLD FRONT BARRELING SOUTH ALONG THE FRONT RANGE OVERNIGHT AND A FULL LATITUDE MULTI-LAYER TROUGH MOVES OVER COLORADO. MODELS HAVE HAD A HECK OF A TIME WITH THIS SYSTEM THE PAST FEW DAYS. ONE MINUTE THEY SHOW AN OPEN WAVE...THE NEXT A DEEP CLOSED LOW. HOWEVER THE PAST TWO RUNS OF THE EC HAVE COME MORE IN LINE WITH THE GFS...NAM AND CANADIAN GEM WHICH SHOW THIS SYSTEM DIPPING AND FORMING A CLOSED LOW IN THE 4-CORNERS AREA LATE SUNDAY NIGHT. THE LATEST 06Z RUN OF THE NAM SHOWS AN EVEN DEEPER SYSTEM NOW. ANYHOW... MODELS MOVE THIS TROUGH/UPR LOW ALONG WITH MUCH COOLER AND WETTER AIR ACROSS THE AREA ON MONDAY. COULD SEE PCPN IN THE FROM OF RAIN AND SNOW AT LOWER ELEVATIONS MONDAY MORNING AND LATER MONDAY AFTN AND EVENING. FOR NOW WILL STICK WITH SCATTERED POPS. HIGH ELEVATIONS...PARTICULARLY THE EAST FACE OF THE FRONT RANGE...HAS THE POTENTIAL TO SEE MEASURABLE SNOWFALL SHOULD WE SEE THIS SYSTEM WRAPPING AS MODELS NOW INDICATE. MAY NOT CLIMB OUT OF THE 40S AT LOWER ELEVATIONS ON THE PLAINS...COLDEST WE/VE SEEN IN QUITE SOME TIME. LOOKING AHEAD...SYSTEM SLOWLY MOVES OUT WITH TEMPERATURES RETURNING ABOVE AVERAGE BY MIDWEEK AND POSSIBLY BACK TO THE 80 DEG MARK ON THE PLAINS BY THE END OF THE WEEK UNDER A BIG RIDGE OF HIGH PRESSURE. AVIATION...THERE WILL BE PERIODS OF HIGH CLOUDS THROUGH THE NEXT 24 HOURS. NORMAL DRAINAGE WINDS THIS MORNING TO SHIFT WESTERLY THIS AFTERNOON. EXPECT A PERIOD OF LIGHT AND VARIABLE WINDS LATE THIS MORNING. WINDS WILL REMAIN LIGHT TODAY...LESS THAN 12 KNOTS. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....BAKER AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1010 PM CDT SAT MAR 31 2012 .DISCUSSION... 908 PM CDT SOME MINOR CHANGES TO POPS AND WX FOR TONIGHT. MAINLY DELAYING ARRIVAL OF THREAT OF SHRA AND TSRA UNTIL LATER TONIGHT AND REDUCING POPS OVER FAR NE IL FOR OVERNIGHT. RADAR COMPOSITE SHOWS WEAK ECHOES TO THE W THRU N OF THE LOCAL AREA WHERE INITIAL WAA AND RESULTING UVV AT MAINLY MID LEVELS OCCURRING. EXPECT THESE ECHOES...ALREADY MOSTLY VIRGA UPSTREAM WITH FEW IF ANY METARS REPORTING ANY PRECIP...WILL CONTINUE TO DRY UP AS THEY MOVE INTO INCREASINGLY DRY MID AND LOW LEVELS. A THUNDERSTORM DEVELOPED JUST NE OF DSM AROUND 0030Z AND ARE SLOWLY INCREASING IN NUMBER AS THEY MOVE ENE-E. THESE TSRA ARE WHERE BETTER MOISTURE IN THE 850 TO 800 HPA LAYER IS IN PLACE...WHERE WEAK SURFACE CONVERGENCE IS OCCURRING...WHERE NOSE OF 45 KT SOUTHWESTERLY JET AT 5 TO 6 K FT AGL SHOWN BY KDMX VAD WIND PROFILE IS LOCATED...AND JUST AHEAD OF WEAK MID LEVEL SHORT WAVE TROF MOVING OVER CENTRAL IA. CHALLENGE TO FORECAST IS HOW EXTENSIVE FURTHER TSRA DEVELOPMENT WILL BE AND WHERE AREA OF STORMS IS LIKELY TO MOVE OVERNIGHT. LATEST RUC13 RUN INDICATES A RATHER SMALL AREA OF MID LEVEL ISENTROPIC LIFT CURRENTLY OVER CENTRAL IA MOVES THIS AREA EASTWARD TO E CENTRAL IA 04-06Z...AND THEN SOUTHEASTWARD ACROSS N CENTRAL IL TO THE CENTRAL IL-IND BORDER BY 12Z. THIS APPEARS TO BE BEST TRACK FOR THE ELEVATED TSRA THAT IS EXPECTED TO BE MAINTAINED THROUGH THE OVERNIGHT BY THE LLJ...THE MID LEVEL SHORT WAVE AND STEEPENING MID LEVEL LAPSE RATES. EXPECT RATHER SMALL AREA OF TSRA AS MOISTURE WILL BE MARGINAL SO ONLY ANTICIPATE ACTIVITY WHERE FORCING FACTORS ARE MAXIMIZED DURING THE OVERNIGHT. TRS //PREV DISCUSSION... 317 PM CDT MAIN FORECAST ISSUES/CONCERNS FOR THE REMAINDER OF THE WEEKEND ARE WITH CHANCES FOR SHOWERS/THUNDERSTORMS LATE TONIGHT INTO SUNDAY MORNING...AS WELL AS TEMPERATURE TRENDS SUNDAY. WITH THE LOW LEVEL CLOUD COVER TODAY MASKING THE FACT THAT HIGH PRESSURE IS OVERHEAD...RELATIVELY QUIET CONDITIONS HAVE BEEN IN PLACE FOR ALL OF TODAY. ALTHOUGH...OVER THE LAST COUPLE OF HOURS SEVERAL HOLES DEVELOPED WITHIN THIS LOW LEVEL MOISTURE. A WARM SUN AND DRIER AIR ALOFT HAS ALLOWED FOR THESE HOLES TO CONTINUE TO EXPAND WITH SOME AREAS ACROSS THE SOUTHERN CWA OBSERVING SUNNY TO PARTLY CLOUDY SKIES. WITHIN THESE AREAS OF BETTER SOLAR INSOLATION...TEMPS HAVE QUICKLY RISEN INTO THE 50S WITH SOME AREAS OBSERVING SOME PLEASANT CONDITIONS AS RATHER LIGHT FLOW REMAINS IN PLACE. EXPECT THIS LOW CLOUD SHIELD TO CONTINUE TO ERODE WITH TIME LATE THIS AFTERNOON AND EARLY EVENING BUT WITH SOME MID AND HIGH LEVEL CLOUD COVER TO PUSH OVERHEAD. THIS IN ITSELF SHOULD PROVIDE PARTLY CLOUDY SKIES FOR TONIGHT...BUT WITH PRECIP CHANCES LATER TONIGHT TO POSSIBLY BRING MORE CLOUDY CONDITIONS MORE TOWARDS EARLY SUNDAY MORNING. LATEST GUIDANCE CONTINUES TO INDICATE SHOWERS AND THUNDERSTORMS DEVELOPING TONIGHT ACROSS EASTERN IOWA AND SHIFTING EAST/SOUTHEAST ACROSS A PORTION OF THE CWA THROUGH SUNDAY MORNING. ALL GUIDANCE IS INDICATING THIS POSSIBILITY BUT WITH SOME VARIABILITY STILL REMAINING WITH REGARDS TO EXACT TIMING AND PLACEMENT/TRACK. WITH BACKING 850MB FLOW...A WARMER AND MORE MOIST AIR MASS LOCATED ACROSS THE CENTRAL PLAINS WILL ADVECT NORTH/NORTHEAST WITH TIME TONIGHT BRINGING HIGHER DEW POINT AIR TO THE REGION. NORTHWEST FLOW ALOFT WILL STEER A MID LEVEL IMPULSE AND ATTENDANT SURFACE TROUGH OUT OF THE NORTHERN PLAINS THIS EVENING...AND HELP TO INITIATE CONVECTION ALONG A LOW LEVEL BAROCLINIC ZONE DRAPED ACROSS THE REGION. WITH LOW LEVEL FLOW FEEDING HIGHER THETA E AIR OVER THIS BOUNDARY AND INTO ANY DEVELOPING PRECIP...THIS AREA OF CONVECTION COULD SEE SOME EXPANSION IN COVERAGE AS IT SHIFTS EAST/SOUTHEAST THROUGH THE CWA EARLY SUNDAY MORNING. ALTHOUGH...GUIDANCE CONTINUES TO STRUGGLE WITH EXACT TIMING OF WHEN CONVECTION WILL DEVELOP AND WHERE THIS DEVELOPING AREA OF PRECIPITATION WILL PROGRESS THROUGH. DUE TO THIS UNCERTAINTY STILL IN PLACE...HAVE NOT MADE MANY CHANGES TO THE GOING POP GRIDS FOR TONIGHT KEEPING HIGH CHANCE POPS FOR MUCH OF THE CWA AFTER THE MIDNIGHT TIME FRAME THROUGH MID MORNING SUNDAY. THIS IS BASED ON THE LIKELIHOOD THAT CONVECTION SHOULD BEGIN TO DEVELOP OVER IOWA ONCE WE DECOUPLE AND THE LLJ RAMPS UP...WHICH SHOULD BE AROUND THE 3Z-6Z TIME FRAME. SOME HI RES DATA IS SHOWING THE POSSIBILITY OF AN MCS DEVELOPING AND QUICKLY SHIFTING THROUGH THE REGION SUNDAY MORNING. HAVE NOT COMPLETELY THROWN THIS OUT AS A POSSIBILITY...WITH DECENT LOW LEVEL SHEAR TO BE PRESENT ACROSS THE REGION. A LIMITING FACTOR WILL BE THE AMOUNT OF INSTABILITY PRESENT OVER NORTHERN ILLINOIS AND NORTHWEST...WHICH AM CURRENTLY LEANING MORE ON THE SREF MUCAPE OUTPUT WHICH IS SHOWING WEAKER INSTABILITY PRESENT BY EARLY SUNDAY MORNING LIMITING MORE ROBUST CONVECTION...WITH OTHER GUIDANCE OF COURSE ALSO VARYING TO THIS AMOUNT. SO WITH ANY PRECIP WHICH MOVES THROUGH THE AREA LATE TONIGHT AND EARLY SUNDAY MORNING...A MORE LIKELY SCENARIO WILL BE FOR THIS TO BE AN UNORGANIZED AREA OF SHOWERS AND ELEVATED THUNDERSTORMS WITH LITTLE CHANCES FOR SEVERE WEATHER...HAIL/WIND. ONLY AN ISOLATED THREAT OF HAIL COULD BE OBSERVED MAINLY FOR THE WESTERN CWA WHERE BETTER INSTABILITY AND STRONGER EFFECTIVE BULK SHEAR WILL RESIDE. EVEN IF A MORE ORGANIZED MCS COULD DEVELOP...WOULD EXPECT IT TO FOLLOW THE HIGHER SURFACE DEW POINT AIR AND BETTER INSTABILITY WHICH WOULD MORE THAN LIKELY BE SITUATED TO THE SOUTH OF THE CWA. THUS...ONCE AGAIN KEEPING ANY THREAT FOR SEVERE WEATHER JUST OUTSIDE OF THE CWA. THIS SITUATION WARRANTS CONTINUED MONITORING...AND WILL MAINTAIN A MENTION FOR THE CHANCES FOR THUNDERSTORMS TONIGHT IN THE HWO. ANY LINGERING SHOWERS/THUNDERSTORMS SHOULD EXIT THE CWA BY MID DAY WITH PARTLY CLOUDY TO SUNNY CONDITIONS EXPECTED THROUGH THE AFTERNOON. THE EXTENT OF THE MORNINGS PRECIP WILL DEFINITELY PLAY A KEY ROLE WITH MAX TEMPS ON SUNDAY WITH PERSISTENT WAA ADVECTING A WARMER AIR MASS OVERHEAD. AS SURFACE WARM FRONT TRIES TO LIFT NORTHEAST ACROSS THE CWA DURING THE DAY SUNDAY...IT WILL ACTUALLY BEGIN TO RETREAT AS A COLD FRONT WITH COOLER LOW LEVEL AIR WORKING ITS WAY BACK WEST ACROSS THE CWA LATE IN THE AFTERNOON AND EARLY EVENING. SO OUTSIDE OF PRECIP TRENDS POSSIBLY AFFECTING TEMP TRENDS SUNDAY...PLACEMENT OF THIS BOUNDARY AND MOVEMENT WILL BE KEY IN DEFINING MAX TEMPS FOR SUNDAY. DID BRING DOWN TEMPS A TAD FROM GOING FORECAST BUT HAVE KEPT THE WEST/SOUTHWEST CWA WARMER THAN THE EAST WITH AREAS STILL TO POSSIBLY REACH THE 80 MARK...AND AREAS ACROSS THE EASTERN CWA TO REACH THE LOWER 70S WITH 60S EXPECTED FOR AREAS NEAR THE LAKE. HAVE ADDED SLIGHT CHANCE POPS FOR THE SOUTHEAST PORTION OF THE CWA FOR SUNDAY AFTERNOON WHERE BETTER FOCUS AND UPPER LEVEL SUPPORT COULD PROVIDE FOR DEVELOPMENT OF THUNDERSTORMS. STRONG UPPER LEVEL RIDGING WILL OCCUR ON MONDAY WITH MID AND UPPER LEVEL FLOW BECOMING RATHER WEAK. THIS WEAK FLOW COINCIDING WITH A FORECASTED CLOSED UPPER LEVEL LOW TRACKING THROUGH THE SOUTHERN US WILL PROVIDE A TRICKY FORECAST THROUGH THE REMAINDER OF THE WEEK WITH THE ANTICIPATION FOR GUIDANCE TO CONTINUE TO STRUGGLE WITH PLACEMENT OF LOW LEVEL FEATURES AND INEVITABLE PRECIP. ALTHOUGH...THERE DOES APPEAR TO BE BETTER CHANCES FOR OBSERVING CONVECTION MONDAY NIGHT. BETTER FORCING AS WELL AS INSTABILITY LOOK TO BE IN PLACE FOR THE DEVELOPMENT OF POSSIBLY MORE ORGANIZED CONVECTION...WITH CURRENT GUIDANCE INDICATING BETTER CHANCES RESIDING ACROSS NORTHERN ILLINOIS INTO EARLY TUESDAY MORNING. HAVE NOT GONE OVERLY EXCITED WITH POPS DURING THIS TIME FRAME AS THE ECMWF REMAINS THE OUTLIER KEEPING A SURFACE LOW AND FORCING/PRECIP OFF TO THE WEST FOR MOST OF MONDAY AND MONDAY NIGHT. IF THIS WERE TO COME INTO FRUITION...THAN DRIER CONDITIONS WOULD BE OBSERVED MONDAY NIGHT WITH PRECIP DELAYED UNTIL TUESDAY. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * POTENTIAL FOR THUNDERSTORMS AFTER 08-09Z. * WINDS SHIFTING NORTHEAST 10-15 KT BY LATE SUNDAY MORNING. * POTENTIAL FOR A PERIOD OF MVFR CEILINGS AROUND 1500 FT BEHIND WIND SHIFT AND LASTING INTO MID AFTERNOON BEFORE SCATTERING. RATZER //DISCUSSION...UPDATED 03Z... ISOLATED STRONG THUNDERSTORMS HAVE DEVELOPED OVER EAST CENTRAL IOWA AS EARLIER ANTICIPATED...AND WERE CLUSTERED ROUGHLY KCID AND KMLI AT 03Z. RADAR TRENDS INDICATE A SOUTHEASTWARD PROPAGATION AS SUPPORTED BY THE LARGE SCALE THERMAL/THICKNESS FIELD...SO CURRENT STORMS SHOULD PASS LARGELY SOUTH OF THE TERMINALS LATER TONIGHT. HOWEVER...HIGH-RES CONVECTION ALLOWING GUIDANCE CONTINUES TO SUGGEST ADDITIONAL DEVELOPMENT OVER FAR NORTHERN/NORTHEAST IL IN THE 08-10Z TIME FRAME...WHICH WOULD LIKELY IMPACT THE TERMINALS VERY CLOSELY IF NOT DIRECTLY IF IT DOES DEVELOP. GUIDANCE HAS BEEN CONSISTENT IN THIS SIGNAL...SO HAVE ELECTED TO CONVERT PROB30 GROUPS TO TEMPOS FOR THE AIRPORTS EARLY SUNDAY MORNING. HAVE TRIED TO NARROW DOWN A 2-3 HOUR WINDOW OF GREATEST PROBABILITY...THOUGH MAY HAVE TO ADJUST LATER IN THE NIGHT BASED ON ACTUAL CONVECTIVE DEVELOPMENT. RATZER PREVIOUS DISCUSSION FROM 00Z... MAIN CONCERNS WITH 00Z TAFS ARE POTENTIAL FOR TSRA LATE TONIGHT INTO EARLY SUNDAY...AS WELL AS THE POTENTIAL FOR A PERIOD OF MVFR CEILINGS DURING THE DAY SUNDAY AS WINDS TURN NORTHEAST OFF THE LAKE. HIGH PRESSURE WAS CENTERED OVER THE CENTRAL GREAT LAKES EARLY THIS EVENING...WHILE A WEAK AREA OF LOW PRESSURE WAS NOTED OVER THE MID-MISSOURI RIVER VALLEY NORTH OF OMAHA. THIS LOW WILL WEAKEN WHILE MOVING EAST ACROSS NORTHERN ILLINOIS BY SUNDAY MORNING. AS THE LOW ADVANCES...WARM MOIST AND UNSTABLE AIR WILL BE FORCED OVER A WARM FRONT EXTENDING FROM SOUTHEAST IOWA INTO CENTRAL ILLINOIS. FORECAST SOUNDINGS DEPICT CONSIDERABLE ELEVATED INSTABILITY TO BE IN PLACE ACROSS EASTERN IOWA AND NORTHERN IL...WHICH COMBINED WITH A 35 KT WEST-SOUTHWEST LOW LEVEL JET AND A SMALL AMPLITUDE SHORT WAVE MOVING FROM IA/MN INTO IL BY 12Z SUNDAY SHOULD ALLOW FOR THUNDERSTORM DEVELOPMENT. HIGH-RES MODELS INDICATE CONVECTIVE INITIATION WILL TAKE PLACE OVER CENTRAL-EASTERN IA THIS EVENING...WITH ELEVATED STORMS THEN SPREADING EAST INTO NORTHERN AND CENTRAL IL AROUND/AFTER MIDNIGHT. WHILE THE OVERALL POTENTIAL FOR THUNDERSTORM DEVELOPMENT APPEARS FAIRLY HIGH...THE MAIN QUESTION IS WHETHER THEY WILL DIRECTLY IMPACT THE TERMINALS. THE COMBINATION OF THE LOW LEVEL JET VEERING WEST OVERNIGHT AND THE NORTHWEST TO SOUTHEAST ORIENTATION OF THE LARGER SCALE THERMAL FIELD SUGGESTS THAT STORMS MAY SCOOT JUST SOUTH OF RFD-ORD-GYY. THUS OVERALL CONFIDENCE IS FAIRLY HIGH THAT STORMS WILL DEVELOP AND BE CLOSE TO THE TERMINAL/TRACON AIRSPACE...BUT LOW THAT THEY WILL MOVE OVER ANY PARTICULAR TERMINAL. WILL HAVE TO WATCH TO SEE WHERE INITIATION OCCURS TO OUR WEST THIS EVENING TO GET A BETTER HANDLE ON TRENDS FARTHER TO THE EAST LATE TONIGHT. ONCE SHOWERS/THUNDERSTORMS MOVE EAST WITH MID-LEVEL AND SURFACE WAVES SUNDAY MORNING...CONCERNS SHIFT TO POTENTIAL FOR MVFR CEILINGS AS LOW LEVEL WINDS SHIFT TO THE NORTHEAST WITH A REINFORCING COOL FRONT. FORECAST SOUNDINGS COOL/SATURATE THE SHALLOW BOUNDARY LAYER WITH CLOUD BASES EXPECTED TO BE AROUND THE 1500 FT LEVEL...WITH DRYING/SCATTERING INDICATED BY MID/LATE AFTERNOON. WINDS...LIGHT EAST-SOUTHEAST WINDS TO BECOME SOUTH OVERNIGHT. WINDS MAY BECOME LIGHT/VARIABLE FOR A TIME SUNDAY MORNING IN VICINITY OF THE SURFACE LOW PRESSURE WAVE...THEN SHOULD SHIFT TO THE NORTHEAST WITH GUSTS AROUND 15 KTS AS FRONT SAGS THROUGH AREA BY MID/LATE MORNING. RATZER //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM-HIGH CONFIDENCE IN TSRA DEVELOPMENT ACROSS FAR NORTHERN IL TONIGHT...BUT LOW CONFIDENCE ON DIRECT IMPACT TO TERMINALS AT THIS TIME. * MEDIUM CONFIDENCE IN CEILING TRENDS SUNDAY. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR WITH CHANCE TSRA MONDAY NIGHT. TUESDAY...VFR WITH CHANCE SHRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. RATZER && .MARINE... 115 PM CDT WINDS WILL TURN SOUTHERLY AND GRADUALLY INCREASE ACROSS LAKE MI TONIGHT AS HIGH PRESSURE MOVES EAST FROM THE CENTRAL GREAT LAKES. LOW PRESSURE WILL EVOLVE EASTWARD ACROSS THE LAKE ON SUNDAY MORNING. AN ASSOCIATED COLD FRONT WILL SLIP SOUTH AS THIS OCCURS...TURNING WINDS NORTHERLY ACROSS THE LAKE. THIS FRONT WILL LIKELY MOVE ACROSS THE NEARSHORE AREAS OF IL AND IN DURING THE EARLY TO MID AFTERNOON ON SUNDAY. HIGH PRESSURE WILL BRIEFLY PREVAIL ON SUNDAY NIGHT BEFORE ANOTHER LOW MOVES EAST ACROSS IOWA INTO NORTHERN ILLINOIS. WINDS ARE EXPECTED TO TURN BACK SOUTHEAST AHEAD OF THIS FEATURE ON MONDAY AFTERNOON...WITH SOME GUSTS UP TO 25 KT...INCLUDING POSSIBLY IN THE ILLINOIS NEAR SHORE AREAS. BEHIND THE LOW PASSAGE LATE MONDAY NIGHT INTO EARLY TUESDAY...THE WINDS WILL ONCE AGAIN SWING BACK NORTHERLY. HIGH PRESSURE IS THEN FORECAST TO ENCOMPASS MUCH OF THE LAKE WEDNESDAY THROUGH FRIDAY...THOUGH CONFIDENCE IN THIS IS FAIRLY LOW DUE TO A CLOSED UPPER LOW IN THE CENTRAL PLAINS WHICH COULD MEANDER CLOSE ENOUGH TO CAUSE SLIGHTLY STRONGER WINDS. OVERALL AT THIS TIME...NO LONG-LIVED GUSTY OR HIGH WAVE PERIODS ARE EXPECTED IN THE NEXT WEEK. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
909 PM CDT SAT MAR 31 2012 .DISCUSSION...UPDATE FOR REST OF TONIGHT... 908 PM CDT SOME MINOR CHANGES TO POPS AND WX FOR TONIGHT. MAINLY DELAYING ARRIVAL OF THREAT OF SHRA AND TSRA UNTIL LATER TONIGHT AND REDUCING POPS OVER FAR NE IL FOR OVERNIGHT. RADAR COMPOSITE SHOWS WEAK ECHOES TO THE W THRU N OF THE LOCAL AREA WHERE INITIAL WAA AND RESULTING UVV AT MAINLY MID LEVELS OCCURRING. EXPECT THESE ECHOES...ALREADY MOSTLY VIRGA UPSTREAM WITH FEW IF ANY METARS REPORTING ANY PRECIP...WILL CONTINUE TO DRY UP AS THEY MOVE INTO INCREASINGLY DRY MID AND LOW LEVELS. A THUNDERSTORM DEVELOPED JUST NE OF DSM AROUND 0030Z AND ARE SLOWLY INCREASING IN NUMBER AS THEY MOVE ENE-E. THESE TSRA ARE WHERE BETTER MOISTURE IN THE 850 TO 800 HPA LAYER IS IN PLACE...WHERE WEAK SURFACE CONVERGENCE IS OCCURRING...WHERE NOSE OF 45 KT SOUTHWESTERLY JET AT 5 TO 6 K FT AGL SHOWN BY KDMX VAD WIND PROFILE IS LOCATED...AND JUST AHEAD OF WEAK MID LEVEL SHORT WAVE TROF MOVING OVER CENTRAL IA. CHALLENGE TO FORECAST IS HOW EXTENSIVE FURTHER TSRA DEVELOPMENT WILL BE AND WHERE AREA OF STORMS IS LIKELY TO MOVE OVERNIGHT. LATEST RUC13 RUN INDICATES A RATHER SMALL AREA OF MID LEVEL ISENTROPIC LIFT CURRENTLY OVER CENTRAL IA MOVES THIS AREA EASTWARD TO E CENTRAL IA 04-06Z...AND THEN SOUTHEASTWARD ACROSS N CENTRAL IL TO THE CENTRAL IL-IND BORDER BY 12Z. THIS APPEARS TO BE BEST TRACK FOR THE ELEVATED TSRA THAT IS EXPECTED TO BE MAINTAINED THROUGH THE OVERNIGHT BY THE LLJ...THE MID LEVEL SHORT WAVE AND STEEPENING MID LEVEL LAPSE RATES. EXPECT RATHER SMALL AREA OF TSRA AS MOISTURE WILL BE MARGINAL SO ONLY ANTICIPATE ACTIVITY WHERE FORCING FACTORS ARE MAXIMIZED DURING THE OVERNIGHT. TRS && .PREV DISCUSSION... 317 PM CDT MAIN FORECAST ISSUES/CONCERNS FOR THE REMAINDER OF THE WEEKEND ARE WITH CHANCES FOR SHOWERS/THUNDERSTORMS LATE TONIGHT INTO SUNDAY MORNING...AS WELL AS TEMPERATURE TRENDS SUNDAY. WITH THE LOW LEVEL CLOUD COVER TODAY MASKING THE FACT THAT HIGH PRESSURE IS OVERHEAD...RELATIVELY QUIET CONDITIONS HAVE BEEN IN PLACE FOR ALL OF TODAY. ALTHOUGH...OVER THE LAST COUPLE OF HOURS SEVERAL HOLES DEVELOPED WITHIN THIS LOW LEVEL MOISTURE. A WARM SUN AND DRIER AIR ALOFT HAS ALLOWED FOR THESE HOLES TO CONTINUE TO EXPAND WITH SOME AREAS ACROSS THE SOUTHERN CWA OBSERVING SUNNY TO PARTLY CLOUDY SKIES. WITHIN THESE AREAS OF BETTER SOLAR INSOLATION...TEMPS HAVE QUICKLY RISEN INTO THE 50S WITH SOME AREAS OBSERVING SOME PLEASANT CONDITIONS AS RATHER LIGHT FLOW REMAINS IN PLACE. EXPECT THIS LOW CLOUD SHIELD TO CONTINUE TO ERODE WITH TIME LATE THIS AFTERNOON AND EARLY EVENING BUT WITH SOME MID AND HIGH LEVEL CLOUD COVER TO PUSH OVERHEAD. THIS IN ITSELF SHOULD PROVIDE PARTLY CLOUDY SKIES FOR TONIGHT...BUT WITH PRECIP CHANCES LATER TONIGHT TO POSSIBLY BRING MORE CLOUDY CONDITIONS MORE TOWARDS EARLY SUNDAY MORNING. LATEST GUIDANCE CONTINUES TO INDICATE SHOWERS AND THUNDERSTORMS DEVELOPING TONIGHT ACROSS EASTERN IOWA AND SHIFTING EAST/SOUTHEAST ACROSS A PORTION OF THE CWA THROUGH SUNDAY MORNING. ALL GUIDANCE IS INDICATING THIS POSSIBILITY BUT WITH SOME VARIABILITY STILL REMAINING WITH REGARDS TO EXACT TIMING AND PLACEMENT/TRACK. WITH BACKING 850MB FLOW...A WARMER AND MORE MOIST AIR MASS LOCATED ACROSS THE CENTRAL PLAINS WILL ADVECT NORTH/NORTHEAST WITH TIME TONIGHT BRINGING HIGHER DEW POINT AIR TO THE REGION. NORTHWEST FLOW ALOFT WILL STEER A MID LEVEL IMPULSE AND ATTENDANT SURFACE TROUGH OUT OF THE NORTHERN PLAINS THIS EVENING...AND HELP TO INITIATE CONVECTION ALONG A LOW LEVEL BAROCLINIC ZONE DRAPED ACROSS THE REGION. WITH LOW LEVEL FLOW FEEDING HIGHER THETA E AIR OVER THIS BOUNDARY AND INTO ANY DEVELOPING PRECIP...THIS AREA OF CONVECTION COULD SEE SOME EXPANSION IN COVERAGE AS IT SHIFTS EAST/SOUTHEAST THROUGH THE CWA EARLY SUNDAY MORNING. ALTHOUGH...GUIDANCE CONTINUES TO STRUGGLE WITH EXACT TIMING OF WHEN CONVECTION WILL DEVELOP AND WHERE THIS DEVELOPING AREA OF PRECIPITATION WILL PROGRESS THROUGH. DUE TO THIS UNCERTAINTY STILL IN PLACE...HAVE NOT MADE MANY CHANGES TO THE GOING POP GRIDS FOR TONIGHT KEEPING HIGH CHANCE POPS FOR MUCH OF THE CWA AFTER THE MIDNIGHT TIME FRAME THROUGH MID MORNING SUNDAY. THIS IS BASED ON THE LIKELIHOOD THAT CONVECTION SHOULD BEGIN TO DEVELOP OVER IOWA ONCE WE DECOUPLE AND THE LLJ RAMPS UP...WHICH SHOULD BE AROUND THE 3Z-6Z TIME FRAME. SOME HI RES DATA IS SHOWING THE POSSIBILITY OF AN MCS DEVELOPING AND QUICKLY SHIFTING THROUGH THE REGION SUNDAY MORNING. HAVE NOT COMPLETELY THROWN THIS OUT AS A POSSIBILITY...WITH DECENT LOW LEVEL SHEAR TO BE PRESENT ACROSS THE REGION. A LIMITING FACTOR WILL BE THE AMOUNT OF INSTABILITY PRESENT OVER NORTHERN ILLINOIS AND NORTHWEST...WHICH AM CURRENTLY LEANING MORE ON THE SREF MUCAPE OUTPUT WHICH IS SHOWING WEAKER INSTABILITY PRESENT BY EARLY SUNDAY MORNING LIMITING MORE ROBUST CONVECTION...WITH OTHER GUIDANCE OF COURSE ALSO VARYING TO THIS AMOUNT. SO WITH ANY PRECIP WHICH MOVES THROUGH THE AREA LATE TONIGHT AND EARLY SUNDAY MORNING...A MORE LIKELY SCENARIO WILL BE FOR THIS TO BE AN UNORGANIZED AREA OF SHOWERS AND ELEVATED THUNDERSTORMS WITH LITTLE CHANCES FOR SEVERE WEATHER...HAIL/WIND. ONLY AN ISOLATED THREAT OF HAIL COULD BE OBSERVED MAINLY FOR THE WESTERN CWA WHERE BETTER INSTABILITY AND STRONGER EFFECTIVE BULK SHEAR WILL RESIDE. EVEN IF A MORE ORGANIZED MCS COULD DEVELOP...WOULD EXPECT IT TO FOLLOW THE HIGHER SURFACE DEW POINT AIR AND BETTER INSTABILITY WHICH WOULD MORE THAN LIKELY BE SITUATED TO THE SOUTH OF THE CWA. THUS...ONCE AGAIN KEEPING ANY THREAT FOR SEVERE WEATHER JUST OUTSIDE OF THE CWA. THIS SITUATION WARRANTS CONTINUED MONITORING...AND WILL MAINTAIN A MENTION FOR THE CHANCES FOR THUNDERSTORMS TONIGHT IN THE HWO. ANY LINGERING SHOWERS/THUNDERSTORMS SHOULD EXIT THE CWA BY MID DAY WITH PARTLY CLOUDY TO SUNNY CONDITIONS EXPECTED THROUGH THE AFTERNOON. THE EXTENT OF THE MORNINGS PRECIP WILL DEFINITELY PLAY A KEY ROLE WITH MAX TEMPS ON SUNDAY WITH PERSISTENT WAA ADVECTING A WARMER AIR MASS OVERHEAD. AS SURFACE WARM FRONT TRIES TO LIFT NORTHEAST ACROSS THE CWA DURING THE DAY SUNDAY...IT WILL ACTUALLY BEGIN TO RETREAT AS A COLD FRONT WITH COOLER LOW LEVEL AIR WORKING ITS WAY BACK WEST ACROSS THE CWA LATE IN THE AFTERNOON AND EARLY EVENING. SO OUTSIDE OF PRECIP TRENDS POSSIBLY AFFECTING TEMP TRENDS SUNDAY...PLACEMENT OF THIS BOUNDARY AND MOVEMENT WILL BE KEY IN DEFINING MAX TEMPS FOR SUNDAY. DID BRING DOWN TEMPS A TAD FROM GOING FORECAST BUT HAVE KEPT THE WEST/SOUTHWEST CWA WARMER THAN THE EAST WITH AREAS STILL TO POSSIBLY REACH THE 80 MARK...AND AREAS ACROSS THE EASTERN CWA TO REACH THE LOWER 70S WITH 60S EXPECTED FOR AREAS NEAR THE LAKE. HAVE ADDED SLIGHT CHANCE POPS FOR THE SOUTHEAST PORTION OF THE CWA FOR SUNDAY AFTERNOON WHERE BETTER FOCUS AND UPPER LEVEL SUPPORT COULD PROVIDE FOR DEVELOPMENT OF THUNDERSTORMS. STRONG UPPER LEVEL RIDGING WILL OCCUR ON MONDAY WITH MID AND UPPER LEVEL FLOW BECOMING RATHER WEAK. THIS WEAK FLOW COINCIDING WITH A FORECASTED CLOSED UPPER LEVEL LOW TRACKING THROUGH THE SOUTHERN US WILL PROVIDE A TRICKY FORECAST THROUGH THE REMAINDER OF THE WEEK WITH THE ANTICIPATION FOR GUIDANCE TO CONTINUE TO STRUGGLE WITH PLACEMENT OF LOW LEVEL FEATURES AND INEVITABLE PRECIP. ALTHOUGH...THERE DOES APPEAR TO BE BETTER CHANCES FOR OBSERVING CONVECTION MONDAY NIGHT. BETTER FORCING AS WELL AS INSTABILITY LOOK TO BE IN PLACE FOR THE DEVELOPMENT OF POSSIBLY MORE ORGANIZED CONVECTION...WITH CURRENT GUIDANCE INDICATING BETTER CHANCES RESIDING ACROSS NORTHERN ILLINOIS INTO EARLY TUESDAY MORNING. HAVE NOT GONE OVERLY EXCITED WITH POPS DURING THIS TIME FRAME AS THE ECMWF REMAINS THE OUTLIER KEEPING A SURFACE LOW AND FORCING/PRECIP OFF TO THE WEST FOR MOST OF MONDAY AND MONDAY NIGHT. IF THIS WERE TO COME INTO FRUITION...THAN DRIER CONDITIONS WOULD BE OBSERVED MONDAY NIGHT WITH PRECIP DELAYED UNTIL TUESDAY. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * LIGHT EAST WINDS BECOMING SOUTH-SOUTHEAST THIS EVENING. * POTENTIAL FOR THUNDERSTORMS LATE TONIGHT INTO EARLY SUNDAY MORNING. * WINDS SHIFTING NORTHEAST 10-15 KT BY LATE SUNDAY MORNING. * POTENTIAL FOR A PERIOD OF MVFR CEILINGS AROUND 1500 FT BEHIND WIND SHIFT AND LASTING INTO MID AFTERNOON BEFORE SCATTERING. RATZER //DISCUSSION...UPDATED 00Z... MAIN CONCERNS WITH 00Z TAFS ARE POTENTIAL FOR TSRA LATE TONIGHT INTO EARLY SUNDAY...AS WELL AS THE POTENTIAL FOR A PERIOD OF MVFR CEILINGS DURING THE DAY SUNDAY AS WINDS TURN NORTHEAST OFF THE LAKE. HIGH PRESSURE WAS CENTERED OVER THE CENTRAL GREAT LAKES EARLY THIS EVENING...WHILE A WEAK AREA OF LOW PRESSURE WAS NOTED OVER THE MID-MISSOURI RIVER VALLEY NORTH OF OMAHA. THIS LOW WILL WEAKEN WHILE MOVING EAST ACROSS NORTHERN ILLINOIS BY SUNDAY MORNING. AS THE LOW ADVANCES...WARM MOIST AND UNSTABLE AIR WILL BE FORCED OVER A WARM FRONT EXTENDING FROM SOUTHEAST IOWA INTO CENTRAL ILLINOIS. FORECAST SOUNDINGS DEPICT CONSIDERABLE ELEVATED INSTABILITY TO BE IN PLACE ACROSS EASTERN IOWA AND NORTHERN IL...WHICH COMBINED WITH A 35 KT WEST-SOUTHWEST LOW LEVEL JET AND A SMALL AMPLITUDE SHORT WAVE MOVING FROM IA/MN INTO IL BY 12Z SUNDAY SHOULD ALLOW FOR THUNDERSTORM DEVELOPMENT. HIGH-RES MODELS INDICATE CONVECTIVE INITIATION WILL TAKE PLACE OVER CENTRAL-EASTERN IA THIS EVENING...WITH ELEVATED STORMS THEN SPREADING EAST INTO NORTHERN AND CENTRAL IL AROUND/AFTER MIDNIGHT. WHILE THE OVERALL POTENTIAL FOR THUNDERSTORM DEVELOPMENT APPEARS FAIRLY HIGH...THE MAIN QUESTION IS WHETHER THEY WILL DIRECTLY IMPACT THE TERMINALS. THE COMBINATION OF THE LOW LEVEL JET VEERING WEST OVERNIGHT AND THE NORTHWEST TO SOUTHEAST ORIENTATION OF THE LARGER SCALE THERMAL FIELD SUGGESTS THAT STORMS MAY SCOOT JUST SOUTH OF RFD-ORD-GYY. THUS OVERALL CONFIDENCE IS FAIRLY HIGH THAT STORMS WILL DEVELOP AND BE CLOSE TO THE TERMINAL/TRACON AIRSPACE...BUT LOW THAT THEY WILL MOVE OVER ANY PARTICULAR TERMINAL. WILL HAVE TO WATCH TO SEE WHERE INITIATION OCCURS TO OUR WEST THIS EVENING TO GET A BETTER HANDLE ON TRENDS FARTHER TO THE EAST LATE TONIGHT. ONCE SHOWERS/THUNDERSTORMS MOVE EAST WITH MID-LEVEL AND SURFACE WAVES SUNDAY MORNING...CONCERNS SHIFT TO POTENTIAL FOR MVFR CEILINGS AS LOW LEVEL WINDS SHIFT TO THE NORTHEAST WITH A REINFORCING COOL FRONT. FORECAST SOUNDINGS COOL/SATURATE THE SHALLOW BOUNDARY LAYER WITH CLOUD BASES EXPECTED TO BE AROUND THE 1500 FT LEVEL...WITH DRYING/SCATTERING INDICATED BY MID/LATE AFTERNOON. WINDS...LIGHT EAST-SOUTHEAST WINDS TO BECOME SOUTH OVERNIGHT. WINDS MAY BECOME LIGHT/VARIABLE FOR A TIME SUNDAY MORNING IN VICINITY OF THE SURFACE LOW PRESSURE WAVE...THEN SHOULD SHIFT TO THE NORTHEAST WITH GUSTS AROUND 15 KTS AS FRONT SAGS THROUGH AREA BY MID/LATE MORNING. RATZER //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH CONFIDENCE IN WIND TRENDS THROUGH TONIGHT. * MEDIUM-HIGH CONFIDENCE IN TSRA DEVELOPMENT TONIGHT...BUT LOW CONFIDENCE ON DIRECT IMPACT TO TERMINALS AT THIS TIME. * MEDIUM CONFIDENCE IN CEILING TRENDS SUNDAY. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR WITH CHANCE TSRA MONDAY NIGHT. TUESDAY...VFR WITH CHANCE SHRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. RATZER && .MARINE... 115 PM CDT WINDS WILL TURN SOUTHERLY AND GRADUALLY INCREASE ACROSS LAKE MI TONIGHT AS HIGH PRESSURE MOVES EAST FROM THE CENTRAL GREAT LAKES. LOW PRESSURE WILL EVOLVE EASTWARD ACROSS THE LAKE ON SUNDAY MORNING. AN ASSOCIATED COLD FRONT WILL SLIP SOUTH AS THIS OCCURS...TURNING WINDS NORTHERLY ACROSS THE LAKE. THIS FRONT WILL LIKELY MOVE ACROSS THE NEARSHORE AREAS OF IL AND IN DURING THE EARLY TO MID AFTERNOON ON SUNDAY. HIGH PRESSURE WILL BRIEFLY PREVAIL ON SUNDAY NIGHT BEFORE ANOTHER LOW MOVES EAST ACROSS IOWA INTO NORTHERN ILLINOIS. WINDS ARE EXPECTED TO TURN BACK SOUTHEAST AHEAD OF THIS FEATURE ON MONDAY AFTERNOON...WITH SOME GUSTS UP TO 25 KT...INCLUDING POSSIBLY IN THE ILLINOIS NEAR SHORE AREAS. BEHIND THE LOW PASSAGE LATE MONDAY NIGHT INTO EARLY TUESDAY...THE WINDS WILL ONCE AGAIN SWING BACK NORTHERLY. HIGH PRESSURE IS THEN FORECAST TO ENCOMPASS MUCH OF THE LAKE WEDNESDAY THROUGH FRIDAY...THOUGH CONFIDENCE IN THIS IS FAIRLY LOW DUE TO A CLOSED UPPER LOW IN THE CENTRAL PLAINS WHICH COULD MEANDER CLOSE ENOUGH TO CAUSE SLIGHTLY STRONGER WINDS. OVERALL AT THIS TIME...NO LONG-LIVED GUSTY OR HIGH WAVE PERIODS ARE EXPECTED IN THE NEXT WEEK. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1013 PM EDT SAT MAR 31 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS...A WEAK FRONTAL SYSTEM MOVING THROUGH COULD BRING CHANCES FOR THUNDERSTORMS ACROSS THE AREA LATE TONIGHT INTO SUNDAY. BY SUNDAY NIGHT UPPER RIDGING SHOULD REBUILD AND DRY THE WEATHER OUT THROUGH MONDAY...BUT BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM WILL APPROACH AND STALL OUT AND BRING THUNDERSTORM CHANCES FOR MONDAY NIGHT THROUGH THURSDAY. MORE UPPER RIDGING WILL DRY THINGS OUT FOR THE WEEKEND. && .NEAR TERM /OVERNIGHT/... LARGE AREA OF LOW STRATUS HAS FINALLY SHIFTED EAST WITH ONLY FAR NORTHEASTERN COUNTIES STILL UNDERNEATH THE DECK. REMAINDER OF THE FORECAST AREA HAD BECOME PARTLY CLOUDY WITH MID AND HIGH LEVEL CLOUDS DRIFTING ACROSS THE REGION. QUITE A RANGE OF TEMPERATURES EXISTED ACROSS THE FORECAST AREA AS OF 00Z...FROM MID 40S OVER THE NORTHEAST WHERE SKIES HAD BEEN CLOUDY ALL DAY TO MID 60S IN THE LOWER WABASH VALLEY. FOCUS FOR THE OVERNIGHT IS POTENTIAL FOR CONVECTION TO IMPACT WESTERN COUNTIES PRIOR TO DAYBREAK. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE DEVELOPMENT OF SCATTERED CONVECTION OVER EASTERN IOWA/WESTERN ILLINOIS SHORTLY AFTER MIDNIGHT AS AN UPPER LEVEL DISTURBANCE MOVES INTO THE REGION. PRESENCE OF A 35KT LOW LEVEL JET AND AXIS OF ELEVATED INSTABILITY SHOULD FURTHER CONTRIBUTE TO CONVECTIVE DEVELOPMENT IN THESE AREAS. STEERING FLOW ALOFT WOULD SUGGEST THAT CONVECTION WILL MOVE SOUTHEAST AND POTENTIALLY MIGRATE INTO THE NORTHERN WABASH VALLEY LATE TONIGHT. HAVE CHOSEN TO EXPAND LOW CHANCE POPS TO ENCOMPASS PORTIONS OF THE FORECAST AREA WEST OF A KOKOMO TO INDY METRO TO TERRE HAUTE LINE BETWEEN 09-12Z. HRRR GUIDANCE SUGGESTIVE OF LEADING EDGE OF CONVECTION ARRIVING INTO THESE AREAS SHORTLY BEFORE DAYBREAK. WHILE STORMS SHOULD BE WEAKENING BY THE TIME THEY ARRIVE IN CENTRAL INDIANA AS THE ENVIRONMENT WILL BE LESS FAVORABLE... POTENTIAL FOR STRONGER CELLS TO PRODUCE SMALL HAIL. WILL CONTINUE TO HIGHLIGHT IN THE HWO. LOWERED TEMPS A DEGREE OR TWO OVERNIGHT BASED ON CURRENT OBS...AND ADJUSTED TIMING AS LOWS LIKELY TO BOTTOM OUT BETWEEN 06 AND 08Z BEFORE ANY STORMS ARRIVE. ZONE AND GRID UPDATES OUT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT ON THE SHORT TERM SO WILL USE A CONSENSUS GENERALLY...BUT THOUGHT EARLY ON THE NAM WAS A LITTLE OVERZEALOUS IN POPS AND PRECIP ARRIVAL WITH THE SUNDAY SYSTEM SO THERE WILL LEAN TOWARD THE GFS/ECMWF/SREFS. COULD HAVE AN MCS ARRIVING IN THE NORTHWEST TO START OUT SUNDAY. VERY WEAK UPPER FORCING WITH A LITTLE SHORTWAVE MOVING THROUGH BUT ISENTROPIC LIFT SHOULD BE GOING THROUGH THE DAY ON SUNDAY. INSTABILITY WILL INCREASE THROUGH THE DAY SO THAT MIXED LAYER CAPES OF 1000 TO 1500 OR SO WILL BE IN PLACE ACROSS THE EAST BY THE AFTERNOON. MARGINAL SHEAR /BOTH DIRECTIONAL AND SPEED/ WILL BE AVAILABLE AS WELL DURING THE AFTERNOON...AND THUS THE INCLUSION OF A SLIGHT RISK FOR SEVERE WEATHER ACROSS MUCH OF THE EASTERN COUNTIES FOR THAT TIME. ALSO HAVE MID LEVEL LAPSE RATES AROUND 7-8C SO EXPECT THE MAIN THREAT TO BE LARGE HAIL. LEFT A SLIGHT CHANCE IN THE FAR EAST THROUGH 3Z AS SYSTEM IS MOVING OUT OF THE AREA. UPPER RIDGING BUILDS BACK IN AND KEPT POPS OUT THROUGH MONDAY. BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM MOVES IN TO NORTHERN ILLINOIS AND POSSIBLY NORTHERN INDIANA. THIS SURFACE LOW AND ISENTROPIC LIFT WILL SERVE AS THE MAIN FORCING MECHANISMS WITHOUT MUCH IN THE WAY OF UPPER FORCING AVAILABLE. WILL HAVE A CHANCE FOR THUNDERSTORMS MONDAY NIGHT AND INTO TUESDAY WITH THIS...WITH HIGHER CHANCES ON TUESDAY WITH THE LOW PASSING OVER THE AREA. FOR HIGH TEMPERATURES GENERALLY STUCK TOWARD THE WARMER END OF THE GUIDANCE ENVELOPE BASED ON RECENT VERIFICATION...AND COULD SEE A DECENT GRADIENT ACROSS THE AREA ON TUESDAY. FOR LOWS WENT A BIT WARMER THAN A CONSENSUS BASED ON EXPECTED CLOUD COVER AND FOR MONDAY NIGHT STUCK NEAR THE WET BULB TEMPERATURES WITH POTENTIAL FOR RAIN. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ENSEMBLES IN GENERAL AGREEMENT IN BRINGING A SYSTEM THAT IS PROGGED TO BE MOVING INTO THE WEST COAST SUNDAY ACROSS THE LOCAL AREA AROUND THE MIDDLE OF NEXT WEEK. ENSEMBLE TREND HAS BEEN TOWARDS CUTTING THIS SYSTEM OFF FROM THE MAIN WESTERLIES...AND TODAY THE MAJORITY OF THE ENSEMBLES POINT IN THIS DIRECTION...WITH THE EFFECTS OF THE CUTOFF AFFECTING THE AREA INTO THURSDAY. WILL GO WITH CHANCE POPS ON WEDNESDAY AND THURSDAY OVER MAINLY THE SOUTHERN ZONES...WHICH WILL BE CLOSER TO CUTOFF LOW. WILL CONTINUE WITH A DRY FORECAST FRIDAY AND SATURDAY AT THIS TIME WITH UPPER RIDGING MOVING THROUGH... ALTHOUGH SOME ENSEMBLES BRING A PRECIPITATION THREAT BACK INTO THE AREA BY NEXT SATURDAY. MAY NEED TO ADD POPS TO NEXT WEEKEND AT A LATER TIME IF FUTURE TRENDS POINT IN THAT DIRECTION. && .AVIATION /DISCUSSION FOR THE 010230Z TAF UPDATE/... KIND VISIBILITY HAS DIPPED INTO MVFR CATEGORY AS OF 02Z. THIS SHOULD CONTINUE INTO THE OVERNIGHT...BUT DO NOT EXPECT MUCH WORSENING OF CONDITIONS GIVEN THICKENING CLOUD COVER. CONVECTION IS DEVELOPING ACROSS IOWA AT THE MOMENT...AND THIS CONVECTION SHOULD EVENTUALLY SLIDE SOUTHEAST TOWARD THE SITE. FOR NOW WILL CONTINUE WITH CB MENTION AROUND 10Z AND WILL CONTINUE TO MONITOR. PREVIOUS DISCUSSION FOLLOWS... VFR EXPECTED INTO THE OVERNIGHT...BUT A POSSIBLE THUNDERSTORM COMPLEX LATER TONIGHT COULD BRING MVFR CONDITIONS. THERE IS ALSO A POSSIBILITY OF MVFR FOG OVERNIGHT. VFR CONDITIONS ARE EXPECTED FOR MUCH OF SUNDAY. ONLY MID AND HIGH CLOUDS ARE EXPECTED FOR THE FIRST SEVERAL HOURS OF THE TAF PERIOD. MODELS ARE HINTING AT A THUNDERSTORM COMPLEX DEVELOPING IN ILLINOIS AFTER 06Z...WITH THE COMPLEX MOVING SOUTHEAST AFTERWARD. BASED ON MODEL AGREEMENT HAVE ADDED CB MENTION AFTER 09Z AND CONTINUING THROUGH 15Z. CONFIDENCE IS MODERATE HERE. IF TSRA AND CLOUDS DO NOT DEVELOP...MVFR FOG MAY FORM. KBMG LOOKS TO HAVE THE LOWEST CHANCE FOR TSRA AT THE MOMENT...SO LEFT MENTION OUT THERE. WITH THE LESSER CHANCE FOR CLOUD COVER FROM TSRA...EXPECT MVFR FOG TO DEVELOP AT KBMG. CONFIDENCE IS LOW IN THIS SOLUTION. AFTER TSRA COMPLEX MOVES OUT OF THE AREA ON SUNDAY...EXPECT SCT-BKN CU. HAVE INCLUDED A BKN060 LAYER FOR MUCH OF THE DAY TO SHOW LEFTOVER CLOUDS FROM TSRA AND THEN THE BKN CU DECK. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....JAS AVIATION...50
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
849 PM EDT SAT MAR 31 2012 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS...A WEAK FRONTAL SYSTEM MOVING THROUGH COULD BRING CHANCES FOR THUNDERSTORMS ACROSS THE AREA LATE TONIGHT INTO SUNDAY. BY SUNDAY NIGHT UPPER RIDGING SHOULD REBUILD AND DRY THE WEATHER OUT THROUGH MONDAY...BUT BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM WILL APPROACH AND STALL OUT AND BRING THUNDERSTORM CHANCES FOR MONDAY NIGHT THROUGH THURSDAY. MORE UPPER RIDGING WILL DRY THINGS OUT FOR THE WEEKEND. && .NEAR TERM /OVERNIGHT/... LARGE AREA OF LOW STRATUS HAS FINALLY SHIFTED EAST WITH ONLY FAR NORTHEASTERN COUNTIES STILL UNDERNEATH THE DECK. REMAINDER OF THE FORECAST AREA HAD BECOME PARTLY CLOUDY WITH MID AND HIGH LEVEL CLOUDS DRIFTING ACROSS THE REGION. QUITE A RANGE OF TEMPERATURES EXISTED ACROSS THE FORECAST AREA AS OF 00Z...FROM MID 40S OVER THE NORTHEAST WHERE SKIES HAD BEEN CLOUDY ALL DAY TO MID 60S IN THE LOWER WABASH VALLEY. FOCUS FOR THE OVERNIGHT IS POTENTIAL FOR CONVECTION TO IMPACT WESTERN COUNTIES PRIOR TO DAYBREAK. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE DEVELOPMENT OF SCATTERED CONVECTION OVER EASTERN IOWA/WESTERN ILLINOIS SHORTLY AFTER MIDNIGHT AS AN UPPER LEVEL DISTURBANCE MOVES INTO THE REGION. PRESENCE OF A 35KT LOW LEVEL JET AND AXIS OF ELEVATED INSTABILITY SHOULD FURTHER CONTRIBUTE TO CONVECTIVE DEVELOPMENT IN THESE AREAS. STEERING FLOW ALOFT WOULD SUGGEST THAT CONVECTION WILL MOVE SOUTHEAST AND POTENTIALLY MIGRATE INTO THE NORTHERN WABASH VALLEY LATE TONIGHT. HAVE CHOSEN TO EXPAND LOW CHANCE POPS TO ENCOMPASS PORTIONS OF THE FORECAST AREA WEST OF A KOKOMO TO INDY METRO TO TERRE HAUTE LINE BETWEEN 09-12Z. HRRR GUIDANCE SUGGESTIVE OF LEADING EDGE OF CONVECTION ARRIVING INTO THESE AREAS SHORTLY BEFORE DAYBREAK. WHILE STORMS SHOULD BE WEAKENING BY THE TIME THEY ARRIVE IN CENTRAL INDIANA AS THE ENVIRONMENT WILL BE LESS FAVORABLE... POTENTIAL FOR STRONGER CELLS TO PRODUCE SMALL HAIL. WILL CONTINUE TO HIGHLIGHT IN THE HWO. LOWERED TEMPS A DEGREE OR TWO OVERNIGHT BASED ON CURRENT OBS...AND ADJUSTED TIMING AS LOWS LIKELY TO BOTTOM OUT BETWEEN 06 AND 08Z BEFORE ANY STORMS ARRIVE. ZONE AND GRID UPDATES OUT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT ON THE SHORT TERM SO WILL USE A CONSENSUS GENERALLY...BUT THOUGHT EARLY ON THE NAM WAS A LITTLE OVERZEALOUS IN POPS AND PRECIP ARRIVAL WITH THE SUNDAY SYSTEM SO THERE WILL LEAN TOWARD THE GFS/ECMWF/SREFS. COULD HAVE AN MCS ARRIVING IN THE NORTHWEST TO START OUT SUNDAY. VERY WEAK UPPER FORCING WITH A LITTLE SHORTWAVE MOVING THROUGH BUT ISENTROPIC LIFT SHOULD BE GOING THROUGH THE DAY ON SUNDAY. INSTABILITY WILL INCREASE THROUGH THE DAY SO THAT MIXED LAYER CAPES OF 1000 TO 1500 OR SO WILL BE IN PLACE ACROSS THE EAST BY THE AFTERNOON. MARGINAL SHEAR /BOTH DIRECTIONAL AND SPEED/ WILL BE AVAILABLE AS WELL DURING THE AFTERNOON...AND THUS THE INCLUSION OF A SLIGHT RISK FOR SEVERE WEATHER ACROSS MUCH OF THE EASTERN COUNTIES FOR THAT TIME. ALSO HAVE MID LEVEL LAPSE RATES AROUND 7-8C SO EXPECT THE MAIN THREAT TO BE LARGE HAIL. LEFT A SLIGHT CHANCE IN THE FAR EAST THROUGH 3Z AS SYSTEM IS MOVING OUT OF THE AREA. UPPER RIDGING BUILDS BACK IN AND KEPT POPS OUT THROUGH MONDAY. BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM MOVES IN TO NORTHERN ILLINOIS AND POSSIBLY NORTHERN INDIANA. THIS SURFACE LOW AND ISENTROPIC LIFT WILL SERVE AS THE MAIN FORCING MECHANISMS WITHOUT MUCH IN THE WAY OF UPPER FORCING AVAILABLE. WILL HAVE A CHANCE FOR THUNDERSTORMS MONDAY NIGHT AND INTO TUESDAY WITH THIS...WITH HIGHER CHANCES ON TUESDAY WITH THE LOW PASSING OVER THE AREA. FOR HIGH TEMPERATURES GENERALLY STUCK TOWARD THE WARMER END OF THE GUIDANCE ENVELOPE BASED ON RECENT VERIFICATION...AND COULD SEE A DECENT GRADIENT ACROSS THE AREA ON TUESDAY. FOR LOWS WENT A BIT WARMER THAN A CONSENSUS BASED ON EXPECTED CLOUD COVER AND FOR MONDAY NIGHT STUCK NEAR THE WET BULB TEMPERATURES WITH POTENTIAL FOR RAIN. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ENSEMBLES IN GENERAL AGREEMENT IN BRINGING A SYSTEM THAT IS PROGGED TO BE MOVING INTO THE WEST COAST SUNDAY ACROSS THE LOCAL AREA AROUND THE MIDDLE OF NEXT WEEK. ENSEMBLE TREND HAS BEEN TOWARDS CUTTING THIS SYSTEM OFF FROM THE MAIN WESTERLIES...AND TODAY THE MAJORITY OF THE ENSEMBLES POINT IN THIS DIRECTION...WITH THE EFFECTS OF THE CUTOFF AFFECTING THE AREA INTO THURSDAY. WILL GO WITH CHANCE POPS ON WEDNESDAY AND THURSDAY OVER MAINLY THE SOUTHERN ZONES...WHICH WILL BE CLOSER TO CUTOFF LOW. WILL CONTINUE WITH A DRY FORECAST FRIDAY AND SATURDAY AT THIS TIME WITH UPPER RIDGING MOVING THROUGH... ALTHOUGH SOME ENSEMBLES BRING A PRECIPITATION THREAT BACK INTO THE AREA BY NEXT SATURDAY. MAY NEED TO ADD POPS TO NEXT WEEKEND AT A LATER TIME IF FUTURE TRENDS POINT IN THAT DIRECTION. && .AVIATION /DISCUSSION FOR THE 010000Z TAFS/... VFR EXPECTED INTO THE OVERNIGHT...BUT A POSSIBLE THUNDERSTORM COMPLEX LATER TONIGHT COULD BRING MVFR CONDITIONS. THERE IS ALSO A POSSIBILITY OF MVFR FOG OVERNIGHT. VFR CONDITIONS ARE EXPECTED FOR MUCH OF SUNDAY. ONLY MID AND HIGH CLOUDS ARE EXPECTED FOR THE FIRST SEVERAL HOURS OF THE TAF PERIOD. MODELS ARE HINTING AT A THUNDERSTORM COMPLEX DEVELOPING IN ILLINOIS AFTER 06Z...WITH THE COMPLEX MOVING SOUTHEAST AFTERWARD. BASED ON MODEL AGREEMENT HAVE ADDED CB MENTION AFTER 09Z AND CONTINUING THROUGH 15Z. CONFIDENCE IS MODERATE HERE. IF TSRA AND CLOUDS DO NOT DEVELOP...MVFR FOG MAY FORM. KBMG LOOKS TO HAVE THE LOWEST CHANCE FOR TSRA AT THE MOMENT...SO LEFT MENTION OUT THERE. WITH THE LESSER CHANCE FOR CLOUD COVER FROM TSRA...EXPECT MVFR FOG TO DEVELOP AT KBMG. CONFIDENCE IS LOW IN THIS SOLUTION. AFTER TSRA COMPLEX MOVES OUT OF THE AREA ON SUNDAY...EXPECT SCT-BKN CU. HAVE INCLUDED A BKN060 LAYER FOR MUCH OF THE DAY TO SHOW LEFTOVER CLOUDS FROM TSRA AND THEN THE BKN CU DECK. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....JAS AVIATION...50
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
750 PM EDT SAT MAR 31 2012 .AVIATION... INITIAL AVIATION PROBLEM IS CIGS AT KFWA. SATELLITE SHOWS CLEARING LINE ON THE EDGE OF KFWA WITH ONLY A SLOW EROSION AS NEXT SYSTEM DEVELOPS UPSTREAM. EXPECT THESE CLOUDS TO SCATTER SHORTLY GIVEN PROXIMITY OF CLEARING TO AIRPORT SEEN ON SATELLITE. SHORT RANGE MODELS STILL HAVING DIFFERENCES RESOLVING EXTENT AND LOCATION OF CONVECTION FOR LATER TONIGHT INTO SUNDAY. FOR THIS TAF PACKAGE HAVE OPTED FOR A BLEND OF HRRR AND 4KM WRF-NMM. THESE MODELS INDICATE CONVECTIVE DEVELOPMENT OVERNIGHT ACROSS IA ALONG WARM FRONT AND MOVE THIS EAST INTO CENTRAL INDIANA SUNDAY MORNING. TAF SITES REMAIN NORTH OF BEST LIFT AND MOST PRECIPITATION THOUGH LIGHTER SHOWERS POSSIBLE AFTER DAYBREAK. FOR NOW ONLY INCLUDED SOME MARGINAL VIS RESTRICTIONS WITH BR LATE TONIGHT AND OPTED TO KEEP PCPN OUT OF TAFS FOR NOW. WILL MONITOR UPSTREAM TRENDS FOR CHANGES WITH NEXT PACKAGE. BACKDOOR COLD FRONT EXPECTED TO DROP SOUTH SUNDAY AFTERNOON WITH WINDS SHIFTING NORTH AROUND OR AFTER 18Z. SOME SCATTERED LIGHT RAIN SHOWERS POSSIBLE WITH THETA E GRADIENT AND MODEST LIFT NEAR FRONT. && .SHORT TERM... /TONIGHT THROUGH SUNDAY NIGHT/ CLOUD COVER HAS BEEN EXTREMELY PERSISTENT UNDER STRONG LL INVERSION IN PLACE ACROSS THE REGION. VIS SATELLITE AND SFC OBS SHOWING CLEARING LINE ADVANCING NE FROM ILLINOIS TOWARDS THE FORECAST AREA. DESPITE NE FLOW...DEPTH OF DRY AIR HAS BEEN FAIRLY LIMITED WITH SUFFICIENT MSTR STILL AROUND TO ALLOW FOR LAKE EFFECT CLOUD BANDS ACROSS EASTERN MICHIGAN. MODELS CONTINUE TO THIN OUT THE CLOUD DECK AND BASED ON SFC OBS WITH SLOWLY RISING CIGS THIS TREND SEEMS REASONABLE. HAVE BACKED OFF ON CLEARING TIMING SOMEWHAT GOING NO BETTER THAN PARTLY TO MOSTLY CLOUDY. TONIGHT...WARM FRONT TO THE SW WILL ONLY EDGE NORTHWARD SOMEWHAT. FLOW OF BETTER LL MSTR AND INCREASING LIFT WILL CONTINUE ACROSS IOWA WHERE NAM12/SPC 4KM WRF INITIATES CONVECTION AFTER 6Z AND MOVES IT SE ACROSS CNTRL IL INTO CNTRL IN. LOCAL WRF ALSO DEVELOPS LIMITED CONVECTION IN EASTERN IOWA BUT CLOSER TO 12Z THEN DROPPING TOWARDS THE FORECAST AREA DURING THE DAY. REGARDLESS OF MODEL OF CHOICE...DRY CONDITIONS WOULD APPEAR TO BE IN STORE THROUGH THE NIGHT SO WILL MAINTAIN THE DRY FORECAST AND LOWS FALLING INTO THE 40S (WARMEST SW). SUN/SUN NGT...AS NOTED ABOVE...SEVERAL SOLUTIONS IN PLACE REGARDING DEVELOPMENT OF CONVECTION WITH REMNANTS EITHER TRACKING ACROSS THE AREA OR COMPLETELY MISSING US. WEAK COLD FRONT WILL BE DROPPING SOUTH DURING THE DAY WITH AT LEAST SOME INSTABILITY ARRIVING AND 70+ KT MID LEVEL JET DYNAMICS ARRIVING DURING THE AFTERNOON. STAGE WOULD BE SET FOR CONVECTION TO EITHER EXPAND OR DEVELOP ACROSS THE AREA DURING THE AFTERNOON. HOWEVER...IF NAM SOLUTION WORKS OUT WITH FURTHER SW TRACK OF MCS AND CUT OFF OF BETTER MSTR...THEN REGION WILL BE LACKING BEST COMBINATION OF EVERYTHING RESULTING IN LOW CHANCES FOR CONVECTION AND MINIMIZED SEVERE THREAT. NEW SWODY2 OUTLOOK PLACED OUR FAR SOUTHERN COUNTIES IN SLGT RISK WITH REMAINDER OF AREA STILL 5%. MID RANGE CHC POPS IS BEST OPTION FOR THE TIME BEING THROUGH THE DAY. WILL HOLD OFF ON ANY SVR MENTION IN ZONES AND MAY BEEF UP WORDING A BIT IN HWO. HIGHS WILL BE HIGHLY DEPENDENT ON CLOUD COVER...BUT CURRENT FORECAST SEEMS REASONABLE AT THIS POINT WITH BUST POTENTIAL LOW TO MODERATE. OTHER THAN A LINGERING SHOWER OR STORM EARLY...DRY CONDITIONS SHOULD PREVAIL SUN NGT. SURROUNDING OFFICES HAVE REMOVED ALL MENTION OF PRECIP WHICH SEEMS REASONABLE SO HAVE FOLLOWED SUIT. LOWS WILL DROP BACK INTO THE UPPER 40S TO UPPER 50S. && .LONG TERM...MONDAY THROUGH SATURDAY UPPER LEVEL PATTERN SLOW TO EVOLVE FOR MONDAY WITH DIGGING UPPER TROUGH EXPECTED TO CUT OFF ACROSS THE FOUR CORNERS REGION WHILE A MORE PROGRESSIVE NORTHERN STREAM TAKES SHAPE ACROSS SOUTHWEST CANADA. AMPLIFIED UPPER LEVEL RIDGING WILL MAINTAIN ITSELF ACROSS THE GREAT LAKES REGION ON MONDAY...WITH LOW LEVEL WARM FRONT/LOW LEVEL JET TO QUICKLY ADVECT A STRONG LOW LEVEL THERMAL RIDGE BACK INTO THE REGION FOR MONDAY AFTERNOON...AND ESPECIALLY BY EVENING. 850/700 HPA LAPSE RATES WILL REMAIN RELATIVELY WEAK HOWEVER AND WITH STRONGEST ISENTROPIC LIFT NOT AFFECTING THE AREA UNTIL EVENING...PROSPECTS FOR ANY SFC BASED OR ELEVATED CONVECTION ARE TOO LOW FOR INCLUSION IN THE FORECAST MONDAY AFTERNOON. LITTLE IF ANY CHANGE TO PREVIOUS FORECAST IN REGARDS TO HIGH TEMPERATURES ON MONDAY WITH ORIENTATION OF WAA/DEPARTING RIDGE AXIS SUPPORTING WARMEST READINGS SOUTHWEST OF UPPER 70S TO NEAR 80...AND COOLEST ACROSS THE NORTHEAST IN THE MID TO UPPER 60S. BY MONDAY EVENING...POSITIVE LOW LEVEL THEATE ADVECTION AND STEEPENING MID LEVEL LAPSE RATES MAY SUPPORT ANOTHER ROUND OF SCATTERED ELEVATED SHOWERS/THUNDERSTORMS. THE PROGRESSIVE NORTHERN STREAM TROUGH TRACKING ACROSS SOUTH CENTRAL CANADA WILL EVENTUALLY DRIVE A SFC LOW/COLD FRONT SOUTHWARD ACROSS THE AREA ON TUESDAY...ALTHOUGH A GOOD DEAL OF UNCERTAINTY REMAINS AS TO HOW QUICKLY THIS BOUNDARY WILL PUSH THROUGH. HAVE UTILIZED A BLEND BETWEEN GFS AND THE SLIGHTLY SLOWER GEM/ECMWF IDEA FOR FRONTAL PROGRESSION ON TUESDAY WITH THESE DIFFERENCES STEMMING MAINLY FROM SUBTLE DIFFERENCES IN TIMING AND AMPLITUDE OF THE NORTHERN STREAM TROUGH. AFTER POTENTIAL ELEVATED CONVECTION MONDAY NIGHT/TUESDAY MORNING...ATTENTION WILL SHIFT TO POSSIBLE AFTERNOON REDEVELOPMENT ALONG AND AHEAD OF THE COLD FRONT...ALTHOUGH TIMING OF THE FRONT MAY END UP FAVORING FAR SOUTHERN AREAS TUESDAY AFTERNOON/EVENING FOR BETTER CONVECTIVE POTENTIAL. STRENGTH OF MID/UPPER LEVEL FORCING ALSO IN QUESTION AS LOCAL AREA BECOMES POSITIONED BETWEEN MORE PRONOUNCED FORCING FROM SOUTHERN/NORTHERN STREAM. WILL MAINTAIN LOW TO MID RANGE CHANCE POPS FOR THUNDER TUESDAY WITH FRONT DROPPING SOUTH OF THE AREA TUESDAY NIGHT. MEDIUM RANGE MODELS FOR WED-FRI ARE FAIRLY CONSISTENT WITH CONSENSUS IDEA TO TAKE SOUTHERN STREAM UPPER LEVEL LOW SOUTH OF THE AREA WEDNESDAY NIGHT INTO THURSDAY WITH BROAD CANADIAN SFC HIGH AND COOLER AIR BUILDING SOUTHWARD. PREDICTABILITY DWINDLES BY LATE DAY 6 AND 7 WITH A GREAT DEAL OF DETERMINISTIC/ENSEMBLE MODEL SPREADS WITH PROGRESSION OF NEXT SIGNIFICANT EASTERN PACIFIC TROUGH. FASTER CLUSTER OF GUIDANCE WOULD SUGGEST LOW POPS ACROSS WESTERN PORTIONS OF FORECAST AREA TOWARD THE END OF THE PERIOD...BUT WILL MAINTAIN DRY DAY 7 FORECAST AT THIS TIME WITH ABOVE NORMAL TEMPS CONTINUING. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...FISHER LONG TERM...MARSILI AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
203 PM EDT FRI MAR 30 2012 .AVIATION.. RISK FOR THUNDER HAS DIMINISHED AT KSBN WITH MAIN ACTIVITY TO REMAIN EAST AND SOUTH OF THE AREA. SHOWERS WILL REMAIN POSSIBLE UNTIL PASSAGE OF THE LOW...WITH PATCHY LIGHT RAIN OR DRIZZLE IN ITS WAKE AS STRATUS MOVES IN FOR THE REMAINDER OF THE NIGHT. AT KFWA...TRICKY FORECAST REMAINS. ACTUAL WARM FRONT STILL RESIDED SOUTH OF KFWA BUT MAY MAKE A BRIEF EXCURSION IN FOR A FEW HOURS. STRONGEST STORMS WILL LIKELY REMAIN JUST SOUTH OF KFWA...BUT WILL BE A CLOSE CALL. ONLY CHANGE TO TEMPO GROUP WAS TO SPEED UP ARRIVAL BY AN HOUR WITH INITIAL SURGE OF CONVECTION DEVELOPING WEST OF THE AIRPORT. AFTER FROPA...SKIES WILL FILL BACK IN WITH STRATUS WHICH WILL LINGER INTO SAT MORNING. && .UPDATE... UPDATE ISSUED TO INCREASE TEMPS IN THE FAR SOUTH AND ADJUST CONVECTIVE THREAT SOMEWHAT SOUTHWARD. SCT LINE OF SHOWERS AND STORMS HAS FORMED ALONG WEAK WAVE MOVING THROUGH THE AREA. THIS SHOULD REMAIN ELEVATED AND MUCH LIKE THIS MORNING SHOULD NOT POSE A SEVERE THREAT. MAIN AREA TO BE WATCHED WILL BE SE THIRD OF THE FORECAST AREA...ROUGHLY SOUTH OF A LOGANSPORT TO FT WAYNE TO PAULDING LINE. STILL LOOKS LIKE IT WILL BE A SMALL WINDOW OF OPPORTUNITY FOR SEVERE TO OCCUR...MAINLY BETWEEN 20Z AND 23Z. WITH INCREASING CLOUD COVER ALONG THE FRONT...HAVE SOME RESERVATIONS ABOUT SEVERE POTENTIAL WITH 60+ DEWPTS REMAINING JUST TO THE SOUTH. HOWEVER...WILL SIDE WITH RUC13 AND NAM 12 AND KEEP WITH SVR THREAT. && .PREV DISCUSSION... /ISSUED 444 AM EDT FRI MAR 30 2012/ SHORT TERM.../TODAY THROUGH SAT NGT/ BROAD SFC LOW OVER IA/SWRN MN THIS MORNING EXPECTED TO CONSOLIDATE AND DEEPEN AS IT MOVES ESE THROUGH A CHICAGO-FWA-LIMA LINE TODAY. LARGE CLUSTER OF TSTMS TO E-NE OF THE SFC LOW IN AREA OF LOW LEVEL THETA-E ADVECTION AND UPR LEVEL DIV. IR IMAGERY SHOWING TREND OF WARMING OF CLOUD TOPS IN THIS AREA... BUT NEW CONVECTION DVLPG FARTHER EAST ACROSS NW INDIANA. EXPECT MUCH OF THE CWA WILL HAVE SHOWERS AND TSTMS THIS MORNING...BUT GREATEST COVERAGE BTWN 12Z-18Z EXPECTED TO BE ACROSS NW 1/2 OF CWA ASSOCIATED WITH TSTM CLUSTER CURRENTLY MOVG THROUGH NW IL/SW WI. TRACK OF SFC LOW ACROSS THE AREA TODAY SHOULD RESULT IN A LARGE TEMP GRADIENT WITH 40S IN OUR MI COUNTIES AND NR 70 IN THE SRN TIER OF OUR INDIANA COUNTIES THIS AFTN. NAM AND LOCAL 12KM WRF INDICATE MODERATE INSTABILITY WILL DVLP OVER SRN PORTION OF OUR CWA THIS AFTN WITH 1000-1500J/KG MLCAPE AND RATHER STRONG 0-6KM SHEAR OF 30-40KT. SPC 4KM WRF SUGGESTS TSTMS WILL DEVELOP ALONG THE CDFNT THIS AFTN AS IT MOVES THROUGH THIS ENVIRONMENT ACROSS SRN PORTION OF OUR CWA. DISCREET STORMS EXPECTED TO QUICKLY TRANSITION INTO A LINE AND RACE EASTWARD ACROSS SRN PORTION OF THE AREA BETWEEN 18-00Z. CONT TO THINK AREAS ALONG AND SOUTH OF A RCR-FDY LINE ARE AT GREATEST RISK OF SVR STORMS THIS AFTN... BUT DEPENDING ON EXACT TRACK OF LOW AND SUBSEQUENT NORTHWARD ADVANCE OF WARM SECTOR... THREAT COULD EXTEND FARTHER NORTH A COUPLE MORE COUNTIES INTO NRN INDIANA AND NW OH PER LATEST SPC DAY1 OUTLOOK. AS LOW CONTS ESE ACROSS THE UPR OH VALLEY TONIGHT... LOW LEVEL CAA SHOULD RESULT IN WIDESPREAD LOW CLOUDS OVER THE AREA WHICH WILL PERSIST INTO SATURDAY MORNING. SKIES SHOULD CLEAR SAT AFTN AS SFC RIDGE MOVES ACROSS THE AREA. DESPITE WK LOW LEVEL FLOW/WAA... EXPECT AFTN SUNSHINE WILL ALLOW TEMPS TO REACH THE MID/U50S OVER MOST OF THE CWA. GOOD RADIATIONAL COOLING EARLY SAT NGT SHOULD GIVE WAY TO INCREASING WAA/CLOUDS/GRADIENT WINDS LATE AS RIDGE MOVES TO THE EAST AND A WK CDFNT DROPS SE ACROSS THE UPR GRTLKS. GIVEN THIS SCENARIO...GENERALLY LEANED TOWARD WARMER GUIDANCE VALUES. LONG TERM... SUNDAY THROUGH THURSDAY...THE MAIN CHALLENGE THIS PERIOD INCLUDES THE TIMING AND TRACK OF SHORT WAVE ENERGY EJECTING EAST EARLY NEXT WEEK. THE PERSISTENT PATTERN OF A NEGATIVE HEIGHT ANOMALY ALONG AND OFF THE WESTERN COAST OF NORTH AMERICA WILL CONTINUE TO KEEP RATHER EXTENSIVE UPPER LEVEL RIDGING OVER THE NORTH AMERICAN INTERIOR. FOR THIS PACKAGE...USED A ECMWF/GFS/CANADIAN GEM ENSEMBLE BLEND WITH ANALOGS. THE ONGOING CHANCES FOR SHOWERS AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY APPEAR ON TRACK. IT LOOKS LIKE A PORTION OF THE SHORT WAVE ENERGY WILL SHEAR OUT TO THE NORTHEAST WITH SOME TYPE OF CUT OFF LOW LINGERING TO THE SOUTH OR SOUTHWEST OF THE AREA. SEVERE STORMS ARE PLAUSIBLE GIVEN CAPES APPROACHING 2000 J/KG WITH UPPER LEVEL SUPPORT. IT HAS BEEN REAL HARD TO TAP MUCH COLD AIR BEHIND THESE SYSTEMS THE PAST SEVERAL WEEKS. THE BEST CHANCE FOR COLD AIR AND FREEZING TEMPERATURES IS LATE IN THE PERIOD AS NORTH TO NORTHEAST FLOW SETS UP WITH A SURFACE RIDGE EXTENDING SOUTH FROM JUST WEST OF HUDSON BAY. OTHERWISE...WENT WITH THE HIGH END CANADIAN AND GFS ENSEMBLE MEMBERS WITH HIGHS WELL INTO THE 70S SUNDAY AND MONDAY GIVEN 850 MB TEMPS 14C TO 17C. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...JT LONG TERM...SKIPPER AVIATION...FISHER UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1125 AM EDT FRI MAR 30 2012 .UPDATE... CONVECTIVE TRENDS CONTINUE TO BE MONITORED ACROSS THE AREA. ELEVATED SHOWERS AND EMBEDDED STORMS WERE PERSISTING EITHER SIDE OF THE IN/OH/MI STATE LINES WITH SPORADIC REPORTS OF PEA SIZE HAIL. THIS ACTIVITY SHOULD REMAIN BELOW SEVERE LEVELS AS IT CONTINUES TO MOVE EAST. ONE STORM HAS DEVELOPED ON THE SW PART OF THIS AREA OF RAIN AND HAS BEEN SHOWING SIGNS OF SOME ORGANIZATION. RADAR DATA AND SFC OBS INDICATE IT IS LIKELY STILL ELEVATED BUT MAY BECOME SFC BASED OVER THE NEXT COUPLE OF HOURS WITH WARM SECTOR RAPIDLY EXPANDING NE TOWARDS SOUTHERN PARTS OF THE AREA. TEMP/DEWPTS HAVE BEEN INCREASE DRAMATICALLY ACROSS CENTRAL AND EC ILLINOIS WHERE NEAR 60 DEWPTS HAVE ALREADY ARRIVE SW OF CMI. RUC13 AND NEW NAM SUGGEST THAT SOUTHERN THIRD TO HALF IS LIKELY IN BEST POSITION FOR STRONG TO SEVERE STORMS WITH SFC BASED LI`S -4 TO -8 C AND CAPES IN EXCESS OF 1000 J/KG. ADDITIONAL CONCERN LIES WITH MODELS SHOWING A FAIR AMOUNT OF ELEVATED INSTABILITY WITH SHOW WALTER VALUES ON THE -2 TO -4 C EVEN INTO THIS AFTERNOON. IN TERMS OF TEMPS...WILL LOOK AT 16Z OBS AND SEE HOW TRENDS ARE IN FAR SOUTHERN AREAS. GIVEN AMOUNT OF CLEARING AHEAD OF ANTICIPATED LINE...A FEW 70S ARE POSSIBLE SOUTH OF US 24. && .PREV DISCUSSION... /ISSUED 657 AM EDT FRI MAR 30 2012/ AVIATION.../12Z TAFS/ SFC LOW PRESSURE REMAINS RATHER BROAD AND DISORGANIZED ACROSS NW IL AND IA THIS MORNING. AREA OF TSTMS E-NE OF THE LOW HAS CONTINUED TO SLOWLY WKN AS IT MOVED EAST ACROSS NERN IL AND SRN LM...BUT SOME BACK-BUILDING TOWARD NW IL IN PAST HOUR. THIS AREA OF SHRA/TS SHOULD MOVE EAST AHEAD OF THE SFC LOW THIS MORNING SO MAINTAINED PREV SBN TAF FCST OF TEMPO TSRA 13Z-17Z. LATEST HIGH RES GUIDANCE CONTS TO SUGGEST LOW WL DEEPEN AS IT MOVES ESE TODAY ALLOWING AIRMASS TO DESTABILIZE OVER NE INDIANA THIS AFTN AHEAD OF THE SYSTEMS CDFNT. THIS SHOULD RESULT LINE OF TSRA DVLPG TO THE WEST OF FWA THIS AFTN AND IMPACTING THE TERMINAL 19Z-22Z. SOME -RA/DZ AND MVFR CIGS SHOULD PERSIST AS THE LOW MOVES TO THE EAST TONIGHT. PREV DISCUSSION... /ISSUED 444 AM EDT FRI MAR 30 2012/ SHORT TERM.../TODAY THROUGH SAT NGT/ BROAD SFC LOW OVER IA/SWRN MN THIS MORNING EXPECTED TO CONSOLIDATE AND DEEPEN AS IT MOVES ESE THROUGH A CHICAGO-FWA-LIMA LINE TODAY. LARGE CLUSTER OF TSTMS TO E-NE OF THE SFC LOW IN AREA OF LOW LEVEL THETA-E ADVECTION AND UPR LEVEL DIV. IR IMAGERY SHOWING TREND OF WARMING OF CLOUD TOPS IN THIS AREA... BUT NEW CONVECTION DVLPG FARTHER EAST ACROSS NW INDIANA. EXPECT MUCH OF THE CWA WILL HAVE SHOWERS AND TSTMS THIS MORNING...BUT GREATEST COVERAGE BTWN 12Z-18Z EXPECTED TO BE ACROSS NW 1/2 OF CWA ASSOCIATED WITH TSTM CLUSTER CURRENTLY MOVG THROUGH NW IL/SW WI. TRACK OF SFC LOW ACROSS THE AREA TODAY SHOULD RESULT IN A LARGE TEMP GRADIENT WITH 40S IN OUR MI COUNTIES AND NR 70 IN THE SRN TIER OF OUR INDIANA COUNTIES THIS AFTN. NAM AND LOCAL 12KM WRF INDICATE MODERATE INSTABILITY WILL DVLP OVER SRN PORTION OF OUR CWA THIS AFTN WITH 1000-1500J/KG MLCAPE AND RATHER STRONG 0-6KM SHEAR OF 30-40KT. SPC 4KM WRF SUGGESTS TSTMS WILL DEVELOP ALONG THE CDFNT THIS AFTN AS IT MOVES THROUGH THIS ENVIRONMENT ACROSS SRN PORTION OF OUR CWA. DISCREET STORMS EXPECTED TO QUICKLY TRANSITION INTO A LINE AND RACE EASTWARD ACROSS SRN PORTION OF THE AREA BETWEEN 18-00Z. CONT TO THINK AREAS ALONG AND SOUTH OF A RCR-FDY LINE ARE AT GREATEST RISK OF SVR STORMS THIS AFTN... BUT DEPENDING ON EXACT TRACK OF LOW AND SUBSEQUENT NORTHWARD ADVANCE OF WARM SECTOR... THREAT COULD EXTEND FARTHER NORTH A COUPLE MORE COUNTIES INTO NRN INDIANA AND NW OH PER LATEST SPC DAY1 OUTLOOK. AS LOW CONTS ESE ACROSS THE UPR OH VALLEY TONIGHT... LOW LEVEL CAA SHOULD RESULT IN WIDESPREAD LOW CLOUDS OVER THE AREA WHICH WILL PERSIST INTO SATURDAY MORNING. SKIES SHOULD CLEAR SAT AFTN AS SFC RIDGE MOVES ACROSS THE AREA. DESPITE WK LOW LEVEL FLOW/WAA... EXPECT AFTN SUNSHINE WILL ALLOW TEMPS TO REACH THE MID/U50S OVER MOST OF THE CWA. GOOD RADIATIONAL COOLING EARLY SAT NGT SHOULD GIVE WAY TO INCREASING WAA/CLOUDS/GRADIENT WINDS LATE AS RIDGE MOVES TO THE EAST AND A WK CDFNT DROPS SE ACROSS THE UPR GRTLKS. GIVEN THIS SCENARIO...GENERALLY LEANED TOWARD WARMER GUIDANCE VALUES. LONG TERM... SUNDAY THROUGH THURSDAY...THE MAIN CHALLENGE THIS PERIOD INCLUDES THE TIMING AND TRACK OF SHORT WAVE ENERGY EJECTING EAST EARLY NEXT WEEK. THE PERSISTENT PATTERN OF A NEGATIVE HEIGHT ANOMALY ALONG AND OFF THE WESTERN COAST OF NORTH AMERICA WILL CONTINUE TO KEEP RATHER EXTENSIVE UPPER LEVEL RIDGING OVER THE NORTH AMERICAN INTERIOR. FOR THIS PACKAGE...USED A ECMWF/GFS/CANADIAN GEM ENSEMBLE BLEND WITH ANALOGS. THE ONGOING CHANCES FOR SHOWERS AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY APPEAR ON TRACK. IT LOOKS LIKE A PORTION OF THE SHORT WAVE ENERGY WILL SHEAR OUT TO THE NORTHEAST WITH SOME TYPE OF CUT OFF LOW LINGERING TO THE SOUTH OR SOUTHWEST OF THE AREA. SEVERE STORMS ARE PLAUSIBLE GIVEN CAPES APPROACHING 2000 J/KG WITH UPPER LEVEL SUPPORT. IT HAS BEEN REAL HARD TO TAP MUCH COLD AIR BEHIND THESE SYSTEMS THE PAST SEVERAL WEEKS. THE BEST CHANCE FOR COLD AIR AND FREEZING TEMPERATURES IS LATE IN THE PERIOD AS NORTH TO NORTHEAST FLOW SETS UP WITH A SURFACE RIDGE EXTENDING SOUTH FROM JUST WEST OF HUDSON BAY. OTHERWISE...WENT WITH THE HIGH END CANADIAN AND GFS ENSEMBLE MEMBERS WITH HIGHS WELL INTO THE 70S SUNDAY AND MONDAY GIVEN 850 MB TEMPS 14C TO 17C. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...JT LONG TERM...SKIPPER AVIATION...JT UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
433 AM EDT FRI MAR 30 2012 .UPDATE... AVIATION SECTION HAS BEEN UDPATED BELOW. && .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS CENTRAL INDIANA WHICH WILL RESULT IN NUMEROUS THUNDERSTORMS FROM TONIGHT THROUGH FRIDAY EVENING. SOME OF THESE COULD BE SEVERE WITH DAMAGING WINDS AND HAIL FRIDAY AFTERNOON AND EVENING. SATURDAY IS EXPECTED TO BE DRY...AND THEN THUNDERSTORM CHANCES WILL RETURN SATURDAY NIGHT AS A WARM FRONT LIFTS NORTHEAST ACROSS CENTRAL INDIANA ON SUNDAY FOLLOWED BY A COLD FRONT ON TUESDAY. && .NEAR TERM /REST OF TONIGHT/... AREA OF SHOWERS ASSOCIATED WITH WEAK ENERGY ALOFT WILL CONTINUE TO PUSH ACROSS THE FORECAST AREA THE NEXT FEW HOURS. THUS WILL KEEP LOW POPS FOR SHOWERS THROUGH THEN. OVERNIGHT...ISENTROPIC LIFT WILL CONTINUE AHEAD OF A WARM FRONT. HOWEVER LIFT IS NOT IMPRESSIVE...AND LATEST HRRR MODEL SHOWS VERY LITTLE CONVECTION OVERNIGHT. THINK THAT THE HRRR MAY BE A BIT UNDERDONE...BUT STILL THE TREND IS FOR LOWER COVERAGE THAN PREVIOUSLY THOUGHT. THUS HAVE LOWERED POPS OUT OF THE LIKELY CATEGORY NORTHWEST AND NUDGED DOWN ELSEWHERE. LOW TEMPERATURES STILL LOOK OK...SO ONLY ADJUSTED HOURLY TRENDS. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... BASED ON LATEST TRENDS AND LATEST MODEL DATA...FEEL THAT POPS DURING FRIDAY MORNING WILL BE LOWER THAN WAS PREVIOUSLY FORECAST. THUS LOWERED POPS TO CHANCE CATEGORY FOR MUCH OF THE MORNING. LIKELY STILL LOOKS GOOD WITH THE COLD FRONT IN THE AFTERNOON. PREVIOUS DISCUSSION FROM THURSDAY AFTERNOON FOLLOWS... MAIN CHALLENGE TO THE FORECAST WILL BE POSSIBILITY OF SEVERE WEATHER ACROSS THE FORECAST AREA FRIDAY AFTERNOON AND EVENING WITH SPC DAY2 SLIGHT RISK FOR DAMAGING WINDS AND LARGE HAIL ACROSS ALL OF CENTRAL INDIANA. MODELS IN FAIR AGREEMENT ON MOVING SURFACE LOW PRESSURE CENTER JUST NORTH OF OUT NORTHERN COUNTIES ON FRIDAY AFTERNOON WITH A COLD FRONT SLIDING SOUTHEAST TO NEAR THE OHIO RIVER FRIDAY EVENING. IN ADDITION...A DECENT UPPER SHORT WAVE WILL MOVE ACROSS DURING THE AFTERNOON IN THE FAST WESTERLY UPPER FLOW. IN ADDITION...MODEL MIXED LAYER CAPES WILL REACH 1000-1500 J/KG WITH THE HIGHER AMOUNTS ACROSS OUR SOUTH. WILL GO WITH LIKELY AFTERNOON POPS WITH PLENTY OF LIFT AND INSTABILITY AND CHANCES POPS LINGERING INTO THE EVENING. DECENT 35 KNOT DEEP LAYER UNIDIRECTIONAL SHEAR ALONG WITH THE INSTABILITY SUGGESTS SLIGHT RISK LOOKS OK WITH LINEAR UPWARD VERTICAL MOTION FIELD SUGGESTING A SQUALL LINE LOOKS VERY POSSIBLE WITH PROPAGATION NORTHWEST TO SOUTHEAST. RIDGING AND A DRYING COLUMN SHOULD ALLOW INCREASING SUNSHINE ON SATURDAY. FINALLY...A WARM FRONT WILL LIFT NORTHEAST INTO CENTRAL INDIANA SATURDAY NIGHT AND SUNDAY AND SHOULD COMBINE WITH INSTABILITY FOR ANOTHER ROUND OF THUNDERSTORMS. WITH MODELS FAR APART IN TEMPERATURES...CONFIDENCE NOT GREAT AND THUS WENT WITH A COMBO OF A BLEND ALONG WITH TRYING TO MATCH UP WITH ADJACENT OFFICES. && .LONG TERM /MONDAY THROUGH THURSDAY/... ON MONDAY AN UPPER RIDGE WILL BE ACROSS OUR REGION WHILE A BROAD UPPER TROUGH WILL EXTEND FROM CENTRAL CANADA TO NEAR NEW MEXICO. ACTUALLY THESE CONSISTS OF TWO SYSTEMS EACH BEING CLOSED UPPER LOWS ONE OVER CENTRAL CANADA AND THE OTHER OVER THE SOUTHWEST U.S. BOTH OF THESE GRADUALLY MOVE TO THE EAST WITH THE CLOSED UPPER LOW MOVING INTO THE DEEP SOUTH AND THE NORTHERN SYSTEM MOVING EAST ACROSS SOUTHERN CANADA. THIS ALLOWS A COLD FRONT TO MOVE INTO OUR REGION BY EARLY THURSDAY AND THEN STALL ACROSS THE SOUTH BY MIDWEEK AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. ONLY SIGNIFICANT CHANGES MADE TO ALL BLEND WAS TO GO CLOSER TO WARMER CONSALL TEMPERATURES MONDAY AND MONDAY NIGHT WITH WARM ADVECTION ACROSS OUR REGION. ON WEDNESDAY NIGHT I LOWERED TEMPERATURES A LITTLE AS MODELS SEEM TO BE A BIT TOO WARM THIS RUN AS SKIES WILL BE MOSTLY CLEAR ALLOWING FOR STRONG RADIATIONAL COOLING. && .AVIATION /DISCUSSION FOR 300900Z KIND TAF UPDATE/... RADAR INDICATEES SCATTERED SHOWERS ADN A FEW SHOWERS WILL PASS NEAR OR JUST NORTH OF KIND. HAVE UPDATED TO ADD TEMPO THUNDER FOR NEXT FEW HOURS. NO OTHER CHANGES NEEDED AT THIS TIME. PREVIOUS AVIATION DISCUSSION FOLLOWS... VFR CONDITIONS EXPECTED THROUGH MIDDAY. IFR CONDITIONS POSSIBLE WITHIN CONVECTION DURING THE AFTERNOON...THEN MVFR CEILINGS THIS EVENING. WARM FRONT APPROACHING EARLY THIS MORNING BUT WITH LIMITED FORCING PRESENT...CONVECTION LIKELY TO REMAIN ISOLATED AT BEST. SKIES MAY CLEAR FOR A BRIEF PERIOD BEFORE MID LEVEL CLOUDS ASSOCIATED WITH THE CONVECTIVE COMPLEX OVER IOWA SPREAD BACK INTO THE REGION. WINDS WILL VEER TO S/SW AND BECOMING GUSTY BY MIDDAY AS THE WARM FRONT LIFTS NORTH THROUGH THE REGION. AS LOW PRESSURE AND AN ASSOCIATED COLD FRONT TRACKS INTO WESTERN INDIANA DURING THE AFTERNOON...CONVECTION EXPECTED TO DEVELOP AND SWEEP ACROSS THE FORECAST AREA THROUGH EARLY EVENING. HIGHEST CONFIDENCE IN CONVECTIVE IMPACTS TO TERMINALS AFTER 17-18Z AND WILL CONTINUE WITH VCTS AT ALL SITES. POTENTIAL EXISTS FOR BRIEF DROPS TO IFR CONDITIONS WITHIN HEAVIER OR LOCALLY SEVERE CONVECTION. WINDS WILL SHIFT TO NORTHWEST BEHIND THE FRONT DURING THE EVENING WITH MODEL SOUNDINGS STRONGLY SUGGESTIVE OF THE DEVELOPMENT OF MVFR STRATOCU DURING THE EVENING AS MOISTURE BECOMES TRAPPED UNDERNEATH A LOW LEVEL INVERSION. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/50 SHORT TERM...MK/50 LONG TERM....JEH AVIATION...RYAN/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
317 AM EDT FRI MAR 30 2012 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS CENTRAL INDIANA WHICH WILL RESULT IN NUMEROUS THUNDERSTORMS FROM TONIGHT THROUGH FRIDAY EVENING. SOME OF THESE COULD BE SEVERE WITH DAMAGING WINDS AND HAIL FRIDAY AFTERNOON AND EVENING. SATURDAY IS EXPECTED TO BE DRY...AND THEN THUNDERSTORM CHANCES WILL RETURN SATURDAY NIGHT AS A WARM FRONT LIFTS NORTHEAST ACROSS CENTRAL INDIANA ON SUNDAY FOLLOWED BY A COLD FRONT ON TUESDAY. && .NEAR TERM /REST OF TONIGHT/... AREA OF SHOWERS ASSOCIATED WITH WEAK ENERGY ALOFT WILL CONTINUE TO PUSH ACROSS THE FORECAST AREA THE NEXT FEW HOURS. THUS WILL KEEP LOW POPS FOR SHOWERS THROUGH THEN. OVERNIGHT...ISENTROPIC LIFT WILL CONTINUE AHEAD OF A WARM FRONT. HOWEVER LIFT IS NOT IMPRESSIVE...AND LATEST HRRR MODEL SHOWS VERY LITTLE CONVECTION OVERNIGHT. THINK THAT THE HRRR MAY BE A BIT UNDERDONE...BUT STILL THE TREND IS FOR LOWER COVERAGE THAN PREVIOUSLY THOUGHT. THUS HAVE LOWERED POPS OUT OF THE LIKELY CATEGORY NORTHWEST AND NUDGED DOWN ELSEWHERE. LOW TEMPERATURES STILL LOOK OK...SO ONLY ADJUSTED HOURLY TRENDS. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... BASED ON LATEST TRENDS AND LATEST MODEL DATA...FEEL THAT POPS DURING FRIDAY MORNING WILL BE LOWER THAN WAS PREVIOUSLY FORECAST. THUS LOWERED POPS TO CHANCE CATEGORY FOR MUCH OF THE MORNING. LIKELY STILL LOOKS GOOD WITH THE COLD FRONT IN THE AFTERNOON. PREVIOUS DISCUSSION FROM THURSDAY AFTERNOON FOLLOWS... MAIN CHALLENGE TO THE FORECAST WILL BE POSSIBILITY OF SEVERE WEATHER ACROSS THE FORECAST AREA FRIDAY AFTERNOON AND EVENING WITH SPC DAY2 SLIGHT RISK FOR DAMAGING WINDS AND LARGE HAIL ACROSS ALL OF CENTRAL INDIANA. MODELS IN FAIR AGREEMENT ON MOVING SURFACE LOW PRESSURE CENTER JUST NORTH OF OUT NORTHERN COUNTIES ON FRIDAY AFTERNOON WITH A COLD FRONT SLIDING SOUTHEAST TO NEAR THE OHIO RIVER FRIDAY EVENING. IN ADDITION...A DECENT UPPER SHORT WAVE WILL MOVE ACROSS DURING THE AFTERNOON IN THE FAST WESTERLY UPPER FLOW. IN ADDITION...MODEL MIXED LAYER CAPES WILL REACH 1000-1500 J/KG WITH THE HIGHER AMOUNTS ACROSS OUR SOUTH. WILL GO WITH LIKELY AFTERNOON POPS WITH PLENTY OF LIFT AND INSTABILITY AND CHANCES POPS LINGERING INTO THE EVENING. DECENT 35 KNOT DEEP LAYER UNIDIRECTIONAL SHEAR ALONG WITH THE INSTABILITY SUGGESTS SLIGHT RISK LOOKS OK WITH LINEAR UPWARD VERTICAL MOTION FIELD SUGGESTING A SQUALL LINE LOOKS VERY POSSIBLE WITH PROPAGATION NORTHWEST TO SOUTHEAST. RIDGING AND A DRYING COLUMN SHOULD ALLOW INCREASING SUNSHINE ON SATURDAY. FINALLY...A WARM FRONT WILL LIFT NORTHEAST INTO CENTRAL INDIANA SATURDAY NIGHT AND SUNDAY AND SHOULD COMBINE WITH INSTABILITY FOR ANOTHER ROUND OF THUNDERSTORMS. WITH MODELS FAR APART IN TEMPERATURES...CONFIDENCE NOT GREAT AND THUS WENT WITH A COMBO OF A BLEND ALONG WITH TRYING TO MATCH UP WITH ADJACENT OFFICES. && .LONG TERM /MONDAY THROUGH THURSDAY/... ON MONDAY AN UPPER RIDGE WILL BE ACROSS OUR REGION WHILE A BROAD UPPER TROUGH WILL EXTEND FROM CENTRAL CANADA TO NEAR NEW MEXICO. ACTUALLY THESE CONSISTS OF TWO SYSTEMS EACH BEING CLOSED UPPER LOWS ONE OVER CENTRAL CANADA AND THE OTHER OVER THE SOUTHWEST U.S. BOTH OF THESE GRADUALLY MOVE TO THE EAST WITH THE CLOSED UPPER LOW MOVING INTO THE DEEP SOUTH AND THE NORTHERN SYSTEM MOVING EAST ACROSS SOUTHERN CANADA. THIS ALLOWS A COLD FRONT TO MOVE INTO OUR REGION BY EARLY THURSDAY AND THEN STALL ACROSS THE SOUTH BY MIDWEEK AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. ONLY SIGNIFICANT CHANGES MADE TO ALL BLEND WAS TO GO CLOSER TO WARMER CONSALL TEMPERATURES MONDAY AND MONDAY NIGHT WITH WARM ADVECTION ACROSS OUR REGION. ON WEDNESDAY NIGHT I LOWERED TEMPERATURES A LITTLE AS MODELS SEEM TO BE A BIT TOO WARM THIS RUN AS SKIES WILL BE MOSTLY CLEAR ALLOWING FOR STRONG RADIATIONAL COOLING. && .AVIATION /DISCUSSION FOR 300600Z TAF ISSUANCE/... VFR CONDITIONS EXPECTED THROUGH MIDDAY. IFR CONDITIONS POSSIBLE WITHIN CONVECTION DURING THE AFTERNOON...THEN MVFR CEILINGS THIS EVENING. WARM FRONT APPROACHING EARLY THIS MORNING BUT WITH LIMITED FORCING PRESENT...CONVECTION LIKELY TO REMAIN ISOLATED AT BEST. SKIES MAY CLEAR FOR A BRIEF PERIOD BEFORE MID LEVEL CLOUDS ASSOCIATED WITH THE CONVECTIVE COMPLEX OVER IOWA SPREAD BACK INTO THE REGION. WINDS WILL VEER TO S/SW AND BECOMING GUSTY BY MIDDAY AS THE WARM FRONT LIFTS NORTH THROUGH THE REGION. AS LOW PRESSURE AND AN ASSOCIATED COLD FRONT TRACKS INTO WESTERN INDIANA DURING THE AFTERNOON...CONVECTION EXPECTED TO DEVELOP AND SWEEP ACROSS THE FORECAST AREA THROUGH EARLY EVENING. HIGHEST CONFIDENCE IN CONVECTIVE IMPACTS TO TERMINALS AFTER 17-18Z AND WILL CONTINUE WITH VCTS AT ALL SITES. POTENTIAL EXISTS FOR BRIEF DROPS TO IFR CONDITIONS WITHIN HEAVIER OR LOCALLY SEVERE CONVECTION. WINDS WILL SHIFT TO NORTHWEST BEHIND THE FRONT DURING THE EVENING WITH MODEL SOUNDINGS STRONGLY SUGGESTIVE OF THE DEVELOPMENT OF MVFR STRATOCU DURING THE EVENING AS MOISTURE BECOMES TRAPPED UNDERNEATH A LOW LEVEL INVERSION. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/50 SHORT TERM...MK/50 LONG TERM....JEH AVIATION...RYAN/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1253 AM EDT FRI MAR 30 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS CENTRAL INDIANA WHICH WILL RESULT IN NUMEROUS THUNDERSTORMS FROM TONIGHT THROUGH FRIDAY EVENING. SOME OF THESE COULD BE SEVERE WITH DAMAGING WINDS AND HAIL FRIDAY AFTERNOON AND EVENING. SATURDAY IS EXPECTED TO BE DRY...AND THEN THUNDERSTORM CHANCES WILL RETURN SATURDAY NIGHT AS A WARM FRONT LIFTS NORTHEAST ACROSS CENTRAL INDIANA ON SUNDAY FOLLOWED BY A COLD FRONT ON TUESDAY. && .NEAR TERM /REST OF TONIGHT/... AREA OF SHOWERS ASSOCIATED WITH WEAK ENERGY ALOFT WILL CONTINUE TO PUSH ACROSS THE FORECAST AREA THE NEXT FEW HOURS. THUS WILL KEEP LOW POPS FOR SHOWERS THROUGH THEN. OVERNIGHT...ISENTROPIC LIFT WILL CONTINUE AHEAD OF A WARM FRONT. HOWEVER LIFT IS NOT IMPRESSIVE...AND LATEST HRRR MODEL SHOWS VERY LITTLE CONVECTION OVERNIGHT. THINK THAT THE HRRR MAY BE A BIT UNDERDONE...BUT STILL THE TREND IS FOR LOWER COVERAGE THAN PREVIOUSLY THOUGHT. THUS HAVE LOWERED POPS OUT OF THE LIKELY CATEGORY NORTHWEST AND NUDGED DOWN ELSEWHERE. LOW TEMPERATURES STILL LOOK OK...SO ONLY ADJUSTED HOURLY TRENDS. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... BASED ON LATEST TRENDS AND LATEST MODEL DATA...FEEL THAT POPS DURING FRIDAY MORNING WILL BE LOWER THAN WAS PREVIOUSLY FORECAST. THUS LOWERED POPS TO CHANCE CATEGORY FOR MUCH OF THE MORNING. LIKELY STILL LOOKS GOOD WITH THE COLD FRONT IN THE AFTERNOON. PREVIOUS DISCUSSION FROM THURSDAY AFTERNOON FOLLOWS... MAIN CHALLENGE TO THE FORECAST WILL BE POSSIBILITY OF SEVERE WEATHER ACROSS THE FORECAST AREA FRIDAY AFTERNOON AND EVENING WITH SPC DAY2 SLIGHT RISK FOR DAMAGING WINDS AND LARGE HAIL ACROSS ALL OF CENTRAL INDIANA. MODELS IN FAIR AGREEMENT ON MOVING SURFACE LOW PRESSURE CENTER JUST NORTH OF OUT NORTHERN COUNTIES ON FRIDAY AFTERNOON WITH A COLD FRONT SLIDING SOUTHEAST TO NEAR THE OHIO RIVER FRIDAY EVENING. IN ADDITION...A DECENT UPPER SHORT WAVE WILL MOVE ACROSS DURING THE AFTERNOON IN THE FAST WESTERLY UPPER FLOW. IN ADDITION...MODEL MIXED LAYER CAPES WILL REACH 1000-1500 J/KG WITH THE HIGHER AMOUNTS ACROSS OUR SOUTH. WILL GO WITH LIKELY AFTERNOON POPS WITH PLENTY OF LIFT AND INSTABILITY AND CHANCES POPS LINGERING INTO THE EVENING. DECENT 35 KNOT DEEP LAYER UNIDIRECTIONAL SHEAR ALONG WITH THE INSTABILITY SUGGESTS SLIGHT RISK LOOKS OK WITH LINEAR UPWARD VERTICAL MOTION FIELD SUGGESTING A SQUALL LINE LOOKS VERY POSSIBLE WITH PROPAGATION NORTHWEST TO SOUTHEAST. RIDGING AND A DRYING COLUMN SHOULD ALLOW INCREASING SUNSHINE ON SATURDAY. FINALLY...A WARM FRONT WILL LIFT NORTHEAST INTO CENTRAL INDIANA SATURDAY NIGHT AND SUNDAY AND SHOULD COMBINE WITH INSTABILITY FOR ANOTHER ROUND OF THUNDERSTORMS. WITH MODELS FAR APART IN TEMPERATURES...CONFIDENCE NOT GREAT AND THUS WENT WITH A COMBO OF A BLEND ALONG WITH TRYING TO MATCH UP WITH ADJACENT OFFICES. && .LONG TERM /MONDAY THROUGH THURSDAY/... ENSEMBLES IN GENERAL AGREEMENT IN BRINGING A SYSTEM THAT IS CURRENTLY PROGGED TO BE MOVING INTO THE WEST COAST OVER THE UPCOMING WEEKEND ACROSS THE LOCAL AREA DURING THE EARLY TO MIDDLE PARTS OF NEXT WEEK. THERE ARE DIFFERENCES WITH RESPECT TO TIMING...BUT IT APPEARS THE BEST CHANCES FOR PRECIPITATION WOULD BE MONDAY NIGHT INTO TUESDAY. SOME OF THE ENSEMBLES INDICATE RATHER LOW SEA LEVEL PRESSURES WITH THIS SYSTEM...SO THERE IS POTENTIAL FOR A SIGNIFICANT SURFACE SYSTEM TO ACCOMPANY THE UPPER TROUGH. WILL GO WITH CHANCE POPS MONDAY AND TUESDAY. A FEW ENSEMBLES CUT OFF THIS TROUGH OVER THE MIDWEST BY THE MIDDLE OF NEXT WEEK...BUT THE MAJORITY OF THE MEMBERS KEEP THIS TROUGH FAIRLY PROGRESSIVE. WILL KEEP NEXT WEDNESDAY AND THURSDAY DRY FOR NOW. && .AVIATION /DISCUSSION FOR 300600Z TAF ISSUANCE/... VFR CONDITIONS EXPECTED THROUGH MIDDAY. IFR CONDITIONS POSSIBLE WITHIN CONVECTION DURING THE AFTERNOON...THEN MVFR CEILINGS THIS EVENING. WARM FRONT APPROACHING EARLY THIS MORNING BUT WITH LIMITED FORCING PRESENT...CONVECTION LIKELY TO REMAIN ISOLATED AT BEST. SKIES MAY CLEAR FOR A BRIEF PERIOD BEFORE MID LEVEL CLOUDS ASSOCIATED WITH THE CONVECTIVE COMPLEX OVER IOWA SPREAD BACK INTO THE REGION. WINDS WILL VEER TO S/SW AND BECOMING GUSTY BY MIDDAY AS THE WARM FRONT LIFTS NORTH THROUGH THE REGION. AS LOW PRESSURE AND AN ASSOCIATED COLD FRONT TRACKS INTO WESTERN INDIANA DURING THE AFTERNOON...CONVECTION EXPECTED TO DEVELOP AND SWEEP ACROSS THE FORECAST AREA THROUGH EARLY EVENING. HIGHEST CONFIDENCE IN CONVECTIVE IMPACTS TO TERMINALS AFTER 17-18Z AND WILL CONTINUE WITH VCTS AT ALL SITES. POTENTIAL EXISTS FOR BRIEF DROPS TO IFR CONDITIONS WITHIN HEAVIER OR LOCALLY SEVERE CONVECTION. WINDS WILL SHIFT TO NORTHWEST BEHIND THE FRONT DURING THE EVENING WITH MODEL SOUNDINGS STRONGLY SUGGESTIVE OF THE DEVELOPMENT OF MVFR STRATOCU DURING THE EVENING AS MOISTURE BECOMES TRAPPED UNDERNEATH A LOW LEVEL INVERSION. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/50 SHORT TERM...MK/50 LONG TERM....JAS AVIATION...RYAN/JH
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1113 PM CDT THU MAR 29 2012 .UPDATE 30/06Z AVIATION DISCUSSION... .SHORT TERM /TONIGHT/... MAIN FOCUS IS SHOWER AND THUNDERSTORM DEVELOPMENT AS SURFACE LOW...CURRENTLY OVER NORTHERN KANSAS MOVES ACROSS SOUTHERN IOWA TONIGHT. WHILE THIS IS HAPPENING...A COLD FRONT ACROSS THE EASTERN DAKOTAS INTO NEBRASKA WILL ALSO MOVE ACROSS IOWA TONIGHT...SO THERE COULD BE TWO ROUNDS OF PRECIPITATION FOCUS. WHAT WAS TO BE A WARM FRONT HAS REMAINED STALLED ALONG THE MISSOURI RIVER IN MISSOURI...WITH ONLY LIMITED PUSH NORTH INTO SE NEBRASKA...DUE TO PERSISTENT CONVECTION IN NORTHERN MISSOURI. FRONT APPEARS UNLIKELY TO MAKE INTO IOWA UNTIL MID OR LATE EVENING...SO THE OPPORTUNITY FOR SURFACE BASED CONVECTION AND SIGNIFICANT SEVERE WEATHER POTENTIAL APPEARS LIMITED. LOW-LEVEL SHEAR AND HELICITY WILL BE MODERATELY STRONG OVER THE SOUTHWESTERN FORECAST AREA...BUT STORMS MOVING INTO THAT AREA ARE LIKELY TO BE SOMEWHAT ELEVATED...SO MAIN THREAT WOULD BE LARGE HAIL AND POTENTIALLY DAMAGING WINDS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP NEAR AND NORTHEAST OF THE SURFACE LOW AS IT TRACKS INTO IOWA THIS EVENING. MORE SCATTERED DEVELOPMENT IS EXPECTED ALONG AND AHEAD OF THE COLD FRONT AS IT MOVES EAST. RUC MODEL SEEMS TO HAVE A GOOD HANDLE ON THIS EVOLUTION. SEVERE THREAT IS LIKELY TO DIMINISH AFTER 9-10 PM. THERE IS SOME POTENTIAL FOR THE SOUTHERN CONVECTION TO BLOSSOM NORTHWARD AS THE COLD FRONT APPROACHES...SO THE HEAVIER PRECIPITATION AXIS IS LIKELY TO BE FROM LAMONI TO EAST OF DES MOINES WITH 0.5-0.75 INCHES POSSIBLE. TEMPERATURES WILL NOT FALL RAPIDLY OVERNIGHT DUE TO CLOUD COVER AND WARM AND MOIST ADVECTION FOR A GOOD PORTION OF THE NIGHT. .LONG TERM /FRIDAY THROUGH THURSDAY/... FORECAST HAS CHANGED SOMEWHAT FROM PREVIOUS ISSUANCES WITH A BIT MORE EMPHASIS ON PRECIP FRIDAY NIGHT AND SATURDAY NIGHT. CURRENT SYSTEM WILL HAVE DEPARTED BY ONSET OF THE PERIOD WITH FAIR WEATHER AND MORE MILD TEMPERATURES FRIDAY. HOWEVER SOME SEMBLANCE OF CURRENT INSTABILITY GRADIENT AND BAROCLINIC ZONE JUST TO OUR SOUTH IS EXPECTED TO RETURN NORTHWARD FRIDAY NIGHT AND COULD VERY WELL ACTIVE MUCH LIKE IT HAS SINCE YESTERDAY. NAM/GFS/SREF ARE NOT REALLY SUGGESTING MUCH IN THE WAY OF PRECIP TOMORROW NIGHT...HOWEVER RECENT GEM REGIONAL AND GLOBAL MODELS AS WELL AS ECMWF RUNS HAVE SUGGESTED ELEVATED CONVECTION WILL DEVELOP OVER EASTERN SECTIONS OVERNIGHT. ECMWF HAS SHOWN NICE BAROCLINIC ZONE AND LIFT ALONG 300K ISENT SURFACE. DO NOT EXPECT ANYTHING SIGNIFICANT BUT AM NO LONGER COMFORTABLE GOING DRY SO SLIGHTS HAVE BEEN INTRODUCED. SIMILAR SITUATION SATURDAY NIGHT ALTHOUGH DOMESTIC MODELS ARE NOW ON BOARD TOO IN SIMILAR AREAS SO HAVE ADDED SLIGHT MENTIONS THERE AS WELL. MODELS CONTINUE TO HAVE VARIED SOLUTIONS FOR SYSTEM EARLY NEXT WEEK WITH DIFFERENT IDEAS ON STRENGTH OF SHORT WAVE IN BASE OF THE LONG WAVE TROUGH AND OVERALL TIMING. GFS/GEM SOLUTIONS ARE SLOWER WITH MORE EMPHASIS ON SRN PLAINS CLOSED LOW WHILE ECWMF HAS MORE NRN STREAM ENERGY AND FASTER SOLUTION. THESE VARIED SOLUTIONS DO NOT HAVE MUCH IMPACT ON SENSIBLE WEATHER HOWEVER WITH CHANCES INCREASE EARLY MONDAY MORNING AND CONTINUE INTO MONDAY EVENING CENTRAL AND EAST. REMAINDER OF THE FORECAST IS MILD AND DRY WITH UPPER LEVEL RIDGING BUILDING BACK INTO THE MO VALLEY. NO FROST OR FREEZING CONDITIONS APPEAR TO BE IN THE OFFING...AT LEAST THROUGH THE END OF THE NEXT WORK WEEK. && .AVIATION...30/06Z THUNDER CONTINUES OVER THE EAST AND ANOTHER LINE FORMING IN THE NORTHWEST WILL MOVE EAST SOUTHEAST THROUGH 11Z. STRONGER STORMS ACROSS THE SOUTH AND EAST WILL AFFECT KALO...KOTM...THROUGH 10Z WITH LOWERING CIGS FROM 06Z THROUGH 11Z AS MOIST BOUNDARY LAYER CONTINUES NEAR SATURATION. HAVE MVFR CIGS/VISBYS WITH SOME CHANCE OF IFR FOR BRIEF PERIOD NORTH AND EAST. OTHERWISE SOME REDUCTION IN VSBY BY 11-14Z THEN IMPROVING FROM 14Z ONWARD. LIGHT WINDS AND GENERALLY VFR CIGS EXPECTED FOR THE REMAINDER OF TAF PERIOD. WINDS SWING BACK TO SOUTHEAST AFT 31/00Z. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...JUNGBLUTH AVIATION...REV LONG TERM...SMALL
AREA FORECAST DISCUSSION
NWS WICHITA KS
708 PM CDT SAT MAR 31 2012 .AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN CONCERN: POTENTIAL FOR IFR/LIFR STRATUS LEE TROUGH WILL ALLOW LIGHT SOUTH-SOUTHEASTERLY WINDS TO CONTINUE OVERNIGHT WITH INCREASING BOUNDARY LAYER MOISTURE. THIS SHOULD RESULT IN IFR (POSSIBLY LIFR) STRATUS DEVELOPMENT OVER MUCH OF THE AREA DURING THE EARLY AM HOURS SUNDAY. THIS IS SUPPORTED IN THE NAM...GFS...RUC...AND 3KM HRRR MODELS. FORECAST CONFIDENCE ABOVE AVERAGE GIVEN THE LOW STRATUS OCCURRENCE IN CENTRAL/SOUTHWEST OK AND NORTH CENTRAL TEXAS THIS MORNING. THE STRATUS LOOKS TO BURN OFF TOWARD MIDDAY SUNDAY. BETTER MIXING AND NEAR FULL SUNSHINE SUNDAY AFTERNOON SHOULD RESULT IN SOUTHERLY GUSTS ~25 KT MOST OF THE AREA. JMC && .PREV DISCUSSION... /ISSUED 243 PM CDT SAT MAR 31 2012/ DISCUSSION... FORECAST CHALLENGES...LOW CLOUD TRENDS TONIGHT/SUNDAY MORNING AND THEN PRECIP CHANCES/TRENDS EARLY NEXT WEEK. TONIGHT-MONDAY LITTLE CHANGE TO THE FORECAST TO CLOSE OUT THE WEEKEND...WITH THE UNSEASONABLE WARMTH CLOSING IN ON SOME RECORDS. FOR THIS EVENING...SOUTHEAST KANSAS WILL REMAIN ON EDGE OF WEAKER CAP WHERE MODERATE INSTABILITY WILL BE PRESENT PRIOR TO DARK. HOWEVER LACK OF FOCUS/TRIGGER SHOULD PRECLUDE CONVECTION SO WILL KEEP FORECAST DRY. SOME PATCHY LIGHT FOG WITH PERHAPS BETTER CHANCE FOR SOME LOW CLOUDS TO DEVELOP AROUND DAWN ACROSS SOUTHERN PORTIONS OF THE AREA WITH CLOUDS LINGERING INTO MIDDAY FOR AREAS EAST OF THE TURNPIKE. OTHERWISE...INCREASING SOUTHERLY FLOW/BETTER MIXING INTO SUNDAY AFTERNOON SHOULD RESULT IN MORE SUNSHINE...WIND AND VERY WARM MAXS ACROSS THE ENTIRE...GENERALLY IN THE 85 TO 90F RANGE. THE APPROACHING UPPER TROF WILL MOVE ACROSS THE SOUTHWEST CONUS SUNDAY NIGHT...BECOMING A CLOSED LOW AS IT MOVES ACROSS THE SOUTHERN ROCKIES DURING MONDAY. THE INHERITED FORECAST SUPPORTS THE LATEST MODEL CONSENSUS IN SLOWING THE SURFACE FRONTAL PASSAGE AND PRECIP/CONVECTIVE CHANCES TO LATER IN THE DAY ON MONDAY. THIS WILL RESULT IN ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES ESPECIALLY FOR LOCATIONS ALONG AND EAST OF THE TURNPIKE. TUESDAY-WEDNESDAY A LITTLE BETTER MODEL CONTINUITY EXISTS WITH THE MOVEMENT OF THE CLOSED UPPER LOW ACROSS MID-AMERICA INTO MID-WEEK...WITH BEST CHANCE FOR SHOWERS/STORMS ON TUESDAY AND WEDNESDAY. THURSDAY-SATURDAY A COUPLE DAYS OF DRY WEATHER EXPECTED IN THE WAKE OF THE DEPARTING UPPER LOW FOR THURSDAY AND FRIDAY. MEANWHILE UPPER TROUGHING WILL DEVELOP ACROSS THE WESTERN CONUS WITH A SIGNIFICANT SHORTWAVE LIFTING NORTHEAST ACROSS THE NORTHERN PLAINS BY SATURDAY. WHILE CONFIDENCE IS MODEST AT BEST...WILL SHOW SMALL PRECIP/CONVECTIVE CHANCES ALONG THE ASSOCIATED SURFACE FRONT FRIDAY NIGHT/SATURDAY. DARMOFAL AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU FAIRLY QUIET AVIATION FORECAST FOR MOST OF THE PERIOD. FEW-SCT DIURNAL CUMULUS THIS AFTERNOON AT KICT-KHUT-KCNU WILL BURN OFF BY 00-02Z. OTHERWISE...DIURNAL COOLING IN CONCERT WITH INCREASING BOUNDARY LAYER MOISTURE MAY PROMOTE A 3-5 HOUR PERIOD OF IFR/LIFR CIGS FROM 10/11Z THROUGH 14/15Z. THE NAM MODEL MAY BE OVER-MOISTENING THE BOUNDARY LAYER AS IT OFTEN DOES...HENCE CONFIDENCE IS LOW ON THIS OCCURRING...SO ONLY HINTED AT IT IN THE 18Z TAFS. ADK FIRE WEATHER... DESPITE UNSEASONBALY WARM TEMPERATURES AND INCREASING WINDS ON SUNDAY...THE GRASSLAND FIRE DANGER RISK IS EXPECTED TO BE ONLY SLIGHTLY ELEVATED DUE TO THE EARLY SPRING GREEN-UP. && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 60 87 61 84 / 0 0 0 20 HUTCHINSON 59 89 59 81 / 0 0 0 20 NEWTON 60 87 62 82 / 0 0 0 20 ELDORADO 60 87 63 85 / 0 0 0 20 WINFIELD-KWLD 61 88 63 86 / 0 0 0 20 RUSSELL 59 91 56 75 / 0 0 0 20 GREAT BEND 58 90 55 77 / 0 0 0 20 SALINA 61 90 60 81 / 0 0 0 20 MCPHERSON 60 89 60 81 / 0 0 0 20 COFFEYVILLE 62 88 66 88 / 0 10 10 10 CHANUTE 61 88 65 87 / 0 10 10 10 IOLA 61 88 65 87 / 0 10 10 10 PARSONS-KPPF 61 88 65 88 / 0 10 10 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
302 PM CDT FRI MAR 30 2012 .DISCUSSION... FORECAST CHALLENGES...ISOLATED STORM CHANCES/PATCHY FOG POTENTIAL TONIGHT...THEN PRECIP CHANCES/COOLING TREND EARLY NEXT WEEK. TONIGHT-SUNDAY DRIER LOW LEVELS IN WAKE OF SURFACE TROF AND NOCTURNAL CONVECTION/OUTFLOW THAT EXITED SOUTHERN KANSAS LAST NIGHT HAS STABILIZED AIRMASS ACROSS THE AREA. HOWEVER THE RUC AND TO A LESSER EXTENT THE HRRR SUGGEST ISOLATED CONVECTION MAY DEVELOP ACROSS THE FLINT HILLS OR SOUTHEAST KANSAS BY EARLY THIS EVENING...WHERE MODEST INSTABILITY WILL RESIDE IN PRESENCE OF WEAKENING INHIBITION. SO WILL KEEP ISOLATED TSRA MENTION FOR AREAS SOUTHEAST OF GREATER WICHITA. IF CONVECTION DEVELOPS IT MAY PERSIST INTO A PORTION OF THE OVERNIGHT HOURS...AIDED BY A WEAK UPPER SHORTWAVE MOVING ACROSS THE LOWER MISSOURI VALLEY. LOCAL PROCEDURES OFF THE SHORT TERM MODELS ARE SUGGESTIVE OF PATCHY FOG AROUND DAWN ACROSS PORTIONS OF SOUTH CENTRAL/SOUTHEAST KANSAS. UNSEASONABLY WARM AND MAINLY DRY WEATHER STILL LOOKS IN ORDER FOR THIS WEEKEND AS A LARGE AMPLITUDE UPPER RIDGE DEVELOPS ACROSS THE PLAINS. ANOTHER MORE SUBTLE UPPER SHORTWAVE WILL RIPPLE THRU THE DEVELOPING RIDGE TO OUR NORTH AND EAST ON SATURDAY AFTERNOON AND EVENING. THIS WILL KEEP MID LEVEL TEMPERATURES RELATIVELY COOL PORTENDING TO WEAK CAPPING ACROSS EASTERN KANSAS...WHERE MODEST DIURNAL INSTABILITY WILL EXIST TOWARD PEAK HEATING. WHILE AN ISOLATED STORM CANNOT BE RULED OUT...WILL KEEP THE FORECAST DRY FOR NOW. SUNDAY LOOKS TO BE THE WARMEST DAY...DARE WE SUGGEST ALMOST HOT...ACROSS THE FORECAST AREA. MAXS SHOULD APPROACH RECORDS IN SOME AREAS NEAR 90F...WITH GUSTY SOUTH WINDS. MONDAY A SIGNIFICANT UPPER TROF WILL MOVE ACROSS THE ROCKIES ON SUNDAY NIGHT AND INTO THE HIGH PLAINS ON MONDAY. WILL CONTINUE TO CARRY MODEST CHANCE POPS AHEAD OF THIS FEATURE AND ASSOCIATED SURFACE FRONT...THOUGH SOMEWHAT SLOWER TIMING SUGGESTED A SLIGHT UP-TWEAK TO MAXS WERE NEEDED AND A BIT SLOWER ONSET TO POPS. TUESDAY-FRIDAY THE MEDIUM RANGE MODELS ARE STILL GRAPPLING WITH HANDLING THE EVENTUAL UPPER FLOW STREAM SEPARATION AND MOVEMENT OF THE CLOSED LOW WHICH BECOMES CUT-OFF FROM THE STRONGER WESTERLIES. THIS LOW WILL IMPACT KANSAS WEATHER AND PRECIP CHANCES THROUGH THE EARLY AND MID-WEEK PERIODS...AND FOR NOW HAVE CONTINUED TO LEAN TOWARD THE HPC GUIDANCE AND MORE PROGRESSIVE GFS. DARMOFAL && .AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU LIGHT WINDS AND CLEAR SKIES ANTICIPATED THROUGH THE NEXT 24 HOURS FOR MOST TERMINALS...ALTHOUGH KCNU SHOULD SEE SOME SCT025-035 CUMULUS THIS AFTERNOON. ADDITIONALLY...CANNOT RULE OUT A STRAY AFTERNOON/EVENING THUNDERSTORM FOR KICT-KCNU ALONG VERY WEAK CONVERGENCE ZONE AHEAD OF SHORTWAVE ENERGY APPROACHING FROM THE NORTHWEST. HOWEVER...THESE CHANCES ARE QUITE LOW. OTHERWISE...DIURNAL COOLING IN CONCERT WITH LIGHT WINDS AND MOIST LOW-LEVELS COULD PROMOTE SOME PATCHY FOG TONIGHT-EARLY SATURDAY...AFFECTING MAINLY KICT-KHUT-KCNU. FOR NOW ONLY WENT 3-5SM VSBYS...ALTHOUGH PATCHY VSBYS COULD GO BRIEFLY LOWER. ADK && .FIRE WEATHER... DESPITE UNSEASONBALY WARM TEMPERATURES AND INCREASING WINDS OVER THE WEEKEND...THE GRASSLAND FIRE DANGER RISK IS EXPECTED TO BE ONLY SLIGHTLY ELEVATED DUE TO THE EARLY SPRING GREEN-UP. && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 58 84 61 87 / 10 10 10 0 HUTCHINSON 56 85 61 88 / 10 10 10 0 NEWTON 58 84 61 87 / 10 10 10 0 ELDORADO 59 84 61 87 / 10 10 10 0 WINFIELD-KWLD 59 84 62 87 / 10 10 10 0 RUSSELL 55 87 59 89 / 10 10 10 0 GREAT BEND 55 86 59 88 / 10 10 10 0 SALINA 57 87 61 89 / 10 10 10 0 MCPHERSON 56 85 61 88 / 10 10 10 0 COFFEYVILLE 59 85 62 88 / 10 10 10 0 CHANUTE 59 84 62 87 / 10 10 10 10 IOLA 59 84 62 87 / 10 10 10 10 PARSONS-KPPF 59 84 62 87 / 10 10 10 0 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
630 PM CDT SAT MAR 31 2012 .UPDATE... UPDATED AVIATION SECTION FOR 00Z TAF ISSUANCE && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 1253 PM CDT SAT MAR 31 2012 AFTER ANY EARLY EVENING CONVECTION DIES DOWN OVER SOUTHEAST MISSOURI...DRY CONDITIONS SHOULD REMAIN OVER THE WFO PAH FORECAST AREA TONIGHT THROUGH MONDAY. IN REVIEWING THE 12Z SUNDAY UPPER AIR ANALYSIS...THERE APPEARED TO BE A SUBTLE 850-700 MB TROUGH/FRONTAL BOUNDARY EXTENDING FROM SOUTHEAST IA...THROUGH CENTRAL IL INTO CENTRAL AND SOUTHEAST INDIANA. WHEN THE LOW LEVEL JET KICKS IN LATER TONIGHT...THE ZONE WILL LIKELY BE THE FOCUS FOR AN OVERNIGHT MESOSCALE CONVECTIVE SYSTEM /MCS/. THE LIFT AND INSTABILITY SHOULD REMAIN WELL TO THE NORTH OF THE WFO PAH FORECAST AREA...AS THE UPPER RIDGE BUILDS IN FROM THE SOUTHWEST TONIGHT INTO SUNDAY. THEREFORE...ANY MENTION OF POP/WEATHER REMAINS OUT OF THE FORECAST AT THIS TIME. FROM EARLIER IN THE WEEK TO TODAY...THE DOMINANCE OF INCREASED THICKNESSES WITH THE BUILDING RIDGE FROM THE SOUTHWEST /EVIDENT IN THE SOUTHWEST U.S. IN THE 12Z UPPER AIR ANALYSIS/ HAS REQUIRED NEARLY DAILY UPWARD ADJUSTMENTS IN THE MAX/MIN TEMPERATURE FORECAST FOR SUNDAY AND MONDAY. NOW THAT THE PRECIPITATION IS NO LONGER AN ISSUE FOR MONDAY AFTERNOON...A BROAD INCREASE TEMPERATURES AND DEWPOINTS /DUE TO THE MOIST SOUTHERLY FLOW UNDER THE SUBSIDENCE INVERSION/ WILL BE EVEN MORE PRONOUNCED. HEAT INDEX VALUES WILL NOT VARY MUCH FROM THE ACTUAL TEMPERATURES...BUT THE EARLY SEASON HEAT MAY BE OF SOME CONCERN FOR THOSE ESPECIALLY SENSITIVE TO THE WARM TEMPERATURES. WE WILL LIKELY TIE OR BREAK BOTH THE CURRENT RECORD MAX TEMPERATURE AND MAXIMUM OVERNIGHT MINIMUM TEMPERATURES FOR APRIL 1ST INTO 2ND. HERE ARE THE CURRENT RECORDS AT THIS TIME FOR EVANSVILLE AND PADUCAH. EVANSVILLE INDIANA APRIL 1ST...RECORD MAX...85 DEGREES SET IN 1940. APRIL 1ST...RECORD MAX MINIMUM TEMPERATURE...62 DEGREES SET IN 1946. APRIL 2ST...RECORD MAX...83 DEGREES SET IN 1967. PADUCAH KENTUCKY APRIL 1ST...RECORD MAX...86 DEGREES SET IN 1946. APRIL 1ST...RECORD MAX MINIMUM TEMPERATURE...60 DEGREES SET IN 1988. APRIL 2ST...RECORD MAX...84 DEGREES SET IN 1946. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 339 PM CDT SAT MAR 31 2012 MAIN ISSUE WITH THE TUE THROUGH THU TIME FRAME LIES WITH YET ANOTHER IN A SEEMINGLY ENDLESS STRING OF SPLIT FLOW UPPER LOWS THIS SEASON THAT TRUDGE SLOWLY EAST OUT OF THE FOUR CORNERS AREA AND INTO THE SOUTHERN PLAINS. OPERATIONAL GFS AND EURO MODELS ARE IN SURPRISING DECENT AGREEMENT WITH THE PLACEMENT OF THE MID LEVEL CIRCULATION WEDNESDAY AFTN. HOWEVER...THEY DIVERGE SOMEWHAT FROM THERE WITH THE OP GFS TAKING MORE OF A NRN ROUTE INTO MO...WHEREAS THE ECMWF DIPS SE INTO AR. TIMING LOOKS GOOD THOUGH AS FAR AS EASTWARD PROGRESSION BY THU AFTN. MEANWHILE...AT THE SFC...ESSENTIALLY A COLD FRONT IS EXPECTED TO DROP SE INTO THE OHIO VALLEY REGION BY TUE NIGHT AND WED...THEN REMAIN NEARLY STATIONARY UNTIL THE SLOW MOVING UPPER LOW CAN PASS BY LATER THU AFTERNOON OR THU NIGHT. THE COMBINATION OF THE MID LEVEL FORCING/ASCENT GENERATED BY THE UPPER LOW...SFC DEW POINTS NEAR 60 AND THE WEAK LOW LEVEL FORCING ASSOCIATED WITH THE SFC FRONT WILL LEAD TO SEVERAL PERIODS OF SCATTERED SHOWERS AND THUNDERSTORMS TUE THROUGH THU. THE UPPER SYSTEM IS NOT NEARLY AS POTENT AS PREVIOUS SPLIT SRN STREAM UPPER LOWS...AND LOW LEVEL FORCING/CONVERGENCE IS NOT IMPRESSIVE. THEREFORE...EVEN THOUGH WE WILL HAVE AN EXTENDED PERIOD OF RAIN/THUNDER CHANCES...WE DO NOT EXPECT EXTENSIVE HEAVY RAINS OR SEVERE STORMS AT THIS TIME. OF COURSE...MAY BE LOCALLY HEAVY DOWNPOURS FROM TIME TO TIME IN SOME LOCATIONS...AND CANNOT RULE OUT A FEW STRONG OR ISOLATED SEVERE STORMS...ESP IF WE CAN GET SOME DAYTIME HEATING AHEAD OF THE MID LEVEL LOW. ALL OF THE CLOUDS AND PERIODS OF RAIN SHOULD HELP HOLD TEMPS DOWN SOME...AND MAY EVEN RETURN TO NEAR NORMAL ONCE THE FRONT PASSES LATE NEXT WEEK. && .AVIATION... ISSUED AT 630 PM CDT SAT MAR 31 2012 STILL SOME CONCERN ABOUT THE POTENTIAL REDEVELOPMENT OF FOG AND LOW STRATUS LATE TONIGHT. THE POTENTIAL APPEARS TO BE MITIGATED BY THE PRESENCE OF DECENT LOW LEVEL SOUTHWEST WINDS ABOVE THE SURFACE. HOWEVER...THE 21Z RUC MODEL INDICATED THE PRESENCE OF A VERY SHALLOW SATURATED LAYER RIGHT NEAR THE SURFACE AFTER 06Z. THE HIGHEST POTENTIAL FOR IFR CONDITIONS APPEARS TO BE IN THE KEVV/KOWB AREA...WHERE TEMP/DEW POINT SPREADS WERE SMALLEST AND SURFACE RELATIVE HUMIDITY WAS HIGHEST TODAY. WHATEVER LOW CLOUDS AND FOG FORM OVERNIGHT WILL DISSIPATE RATHER QUICKLY AFTER SUNRISE...MAINLY DUE TO STRENGTHENING SOUTHWEST LOW LEVEL WINDS. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...SMITH LONG TERM....GM AVIATION...MY
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
410 PM EDT FRI MAR 30 2012 .Short Term (This Afternoon through Saturday Night)... Issued at 405 PM EDT Mar 30 2012 Afternoon satellite imagery and observations reveal that the warm front has moved well north of our forecast area. South of this warm front, the atmosphere continues to destabilize with time. With current temperatures in the upper 70s to the lower 80s and dewpoints in the upper 50s to the lower 60s is resulting in mixed layer CAPE values in the 1250-1750 J/Kg range. Surface lifted indices based on RUC proximity soundings are running around -4 to -6 degrees Celsius. Atmosphere remains generally uncapped across the southeastern/eastern sections of the forecast area. However some weak capping/CINH still exists out in areas west of I-65. Sufficient mixing over the next few hours will likely mix that cap out. For the rest of the afternoon, we expect partly to mostly sunny skies with isolated showers and thunderstorms being possible across portions of the area. The greatest concentration of convection will generally be east of I-65 where we have a local maxima in the dewpoint field. Temperatures will remain in the upper 70s and lower 80s through the early evening before dropping into the upper 70s toward sunset. As for tonight, the latest high resolution models agree that convection will continue to develop along a southward moving cold front which is currently located across central IL, IN, and OH. This line of convection will likely move eastward as it will be embedded in the faster mid-level low aloft. However, the line will slowly sag southward with time. The consensus of the latest models have trended slower as they adjust to the initial conditions that are being ingested into the model. Therefore, the slower solution would keep the bulk of this thunderstorm activity concentrated north of the Ohio River early this evening. Current thinking is that the line will likely sag southward to near the Ohio River by 10-11 PM EDT. As this line head south, it will be encountering a slowly stabilizing airmass due to the loss of heating and nocturnal PBL stabilization. Despite the weaker instability, this line of storms should remain largely intact as it approaches the Ohio River later this evening. The main threats still appear to be damaging winds and large hail. The tornado threat appears to be rather low across our area as overall bulk shear values decrease the further south you go of the Ohio River. As the line passes south of the Ohio River, expect the line to weaken and gradually dissipate as it sinks further south into KY. For this reason, we will keep highest PoP chances tonight across southern Indiana and the northern parts of KY and have lesser chances across southern KY. Overnight lows will cool into the mid-upper 50s. Surface frontal boundary is expected to push south of the state early Saturday with high pressure building into the region. Partly to mostly sunny skies are expected with highs topping out in the upper 60s in the Bluegrass region and lower 70s in the central. Warmest temperatures will be across the south/southwest with mid-upper 70s. Overnight lows Saturday night will be in the upper 30s-lower 40s in the northeast with mid-upper 40s elsewhere. .Long Term (Sunday through Friday)... Updated at 330 PM EDT Mar 30 2012 Ohio Valley will be positioned in northwest mid level flow between ridging over the south central CONUS and shortwave moving from the eastern Great Lakes to New England on Sunday. Surface low associated with northeast shortwave will drag a cold front south toward the Ohio River by Sunday afternoon. At this point, will continue to keep forecast dry however may have to eventually add low chance pops across northern CWA for afternoon showers and storms. Looking for highs in the low 80s on Sunday as skies stay mostly sunny to partly cloudy. Ridge axis slides east to the middle Mississippi River Valley Sunday night with frontal boundary mentioned above sliding southwest over the CWA from a backdoor entrance. Front then looks to stall as it becomes parallel to the mid level flow. Will also continue to keep this period dry as models do not show enough deep moisture to warrant pops at this time. Could see a nice gradient in low temperatures on Sunday night dependent on how much progress front makes. Will go with low 60s west to upper 50s east. Closed upper low will make its way to the southern plains on Monday with surface low developing over the middle Mississippi River Valley. The resultant tightening pressure gradient will create steady southwesterly flow and likely lift stalled frontal boundary back northeast as a warm front. Will include slight chance for a shower or thunderstorm as this occurs. This will be the warmest day of the period with low to mid 80s. Will likely see a lull in activity sometime Monday evening before more widespread precipitation moves over the area through midweek. That being said, will leave chance pops in the east for departing warm front induced showers and storms and uncertainty in timing. Lows around 60 can be expected. Confidence in forecast decreases from Tuesday on as models continue to have trouble with timing on closed upper low meandering from the southern Plains to the Tennessee Valley or the Gulf Coast states. Adding to the uncertainty, models disagree on northern stream energy and its associated surface features dragging a cold front through. ECMWF is more aggressive with front, dragging it through the region by Tuesday night, with closed upper low slower and further south. Meanwhile, GFS/GEM are faster with the upper low which combines the ample Gulf moisture with the front sagging south from northern stream system. This scenarios could result from the differing model solutions. 1.) The ECMWF solution would result in a quick-hitting shower and storm episode from Tuesday afternoon through Wednesday morning. 2.) The GFS/GEM solution would bring a prolonged precipitation event from Tuesday afternoon through at least Thursday evening as upper low would be further north and slower to move through. Will lean toward the first solution at this point with best chances for showers and storms Tuesday afternoon through Wednesday morning. Thereafter, will keep forecast dry until models converge on a solution. Looking for a cool down from midweek with either solution as we will either be in a post frontal cooler airmass or underneath the influence of an upper low. Highs in the mid 60s each day with lows in the mid 40s. && .Aviation (18Z TAF Issuance)... Updated at 105 PM EDT Mar 30 2012 Surface warm frontal boundary has now cleared all the terminals and southwesterly flow is picking up across the region. Partly to mostly sunny skies are expected through the early afternoon hours, but a distinct Cu field is already developing in the warm sector, south of the warm front. Can not completely rule out an isolated thunderstorm or two across the region this afternoon, but feel that the best convective potential will increase this afternoon to our northwest along an approaching frontal boundary. Scattered-broken line of storms will likely develop out ahead of this boundary and head east-southeastward across the area this evening. Feel that the best chances of convection at KSDF/KLEX will be between 30/23Z-31/06Z. Given the uncertainty in the timing, will keep VCTS going in the TAFs for now. Further south at KBWG, storms may not be an issue tonight as the line is expected to weaken due to the loss of instability as it heads southward into KY. Will maintain a VCTS group after 31/04Z. After cold frontal passage late tonight, we`ll see winds kick around to the northwest and then eventually to the northeast during the day on Saturday. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Short Term.......MJ Long Term........BJS Aviation.........MJ
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1255 PM CDT FRI MAR 30 2012 .UPDATE... ISSUED AT 1253 PM CDT FRI MAR 30 2012 LATEST UPDATE INCLUDES NEW AVIATION SECTION AND LONG TERM UPDATE. UPDATE ISSUED AT 1233 PM CDT FRI MAR 30 2012 REFINED THE TIMING AND INTENSITY OF THE POP/WEATHER GRIDS FOR THE REST OF TODAY AND INTO TONIGHT. ADJUSTMENTS WERE ALSO MADE TO REFINE OTHER SENSIBLE WEATHER ELEMENTS...SUCH AS TEMPERATURE...DEWPOINT...WIND...SKY COVER AND RELATIVE HUMIDITY. WITH THE MANDATORY LEVEL UPPER AIR ANALYSIS...THERE WAS A MAXIMUM OF HIGHER THETA-E AIR OVER SOUTHEAST OK...NORTHERN AR...AND SOUTHEAST MISSOURI THIS MORNING...WITH A SECONDARY AREA OVER NORTHERN AND NORTHEAST ILLINOIS. THE BEST LOW LEVEL MOISTURE WAS OVER WEST KENTUCKY...SOUTHEAST ILLINOIS AND SOUTHWEST INDIANA. THE 12KM NAM-WRF AND 3KM HRRR NUMERICAL MODEL MASS/INSTABILITY/RADAR REFLECTIVITY FIELDS SUGGEST THAT THE NORTHERN INDIANA CONVECTION AND NEWLY MINTED CENTRAL KENTUCKY CONVECTION SHOULD GRADUALLY BUILD WESTWARD WITH TIME. THE 0-3/3-6KM NAM-WRF BULK SHEAR REMAINS LOW /15-25 KNOTS/...SO SIGNIFICANT STORM ORGANIZATION MAY NOT BE IN THE CARDS FOR THE AREA. HOWEVER...SHARP LAPSE RATES AND DECENT CAPE/DOWNDRAFT CAPE SUGGEST THE POTENTIAL THAT GOOD UPDRAFTS WILL WARRANT THE MENTION OF AT LEAST SMALL HAIL AND GUSTY WINDS IN THE GRIDDED FORECAST THIS AFTERNOON AND INTO THE EARLY EVENING HOURS. AT THIS TIME...FOCUSED THIS MENTION OF HAIL/WIND IN THE SCATTERED THUNDERSTORM COVERAGE AREA. THE NAM-WRF/GFS/RUC APPEARED TO INITIALIZE BETTER WITH INSTABILITY /LIFTED INDEXES/ AND PRECIPITABLE WATER FROM THE GOES SOUNDER IMAGERY VERSUS THE REST OF THE MODEL GUIDANCE THIS MORNING. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 1233 PM CDT FRI MAR 30 2012 IN LINE WITH THE MIDNIGHT SHIFT ADJUSTMENT FOR POPS/WEATHER TONIGHT INTO SATURDAY...ADJUSTED AND SLIGHTLY INCREASED RAIN CHANCES MAINLY OVER SOUTHEAST MISSOURI. GIVEN THE STRONGER DRY AIR ADVECTION AHEAD OF THE FRONTAL BOUNDARY ON SATURDAY...KEPT RAIN CHANCES OUT OF A VAST MAJORITY OF SOUTHERN ILLINOIS AND WEST KENTUCKY AND ALL OF SOUTHWEST INDIANA. RIDGING ON SUNDAY STILL REMAINS DOMINANT...SO LOW TO MIDDLE 80S AND LIMITED CLOUD COVER REMAIN ON TARGET IN THE FORECAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 1253 PM CDT FRI MAR 30 2012 GENERALLY THE GFS HAS BEEN MORE CONSISTENT IN BRINGING ENERGY OUT OF THE SOUTHWEST U.S. EARLY IN THE WEEK...IN THE FORM OF A CUT OFF AS IT MOVES ACROSS THE SOUTHERN PLAINS AND TOWARD THE MISSISSIPPI VALLEY REGION. THE GFS AND GEM MODELS ARE IN DECENT AGREEMENT AND WE GENERALLY USED A BLEND OF THE TWO AS A GUIDE. H5 RIDGING ACROSS THE REGION SHOULD KEEP MONDAY ESSENTIALLY DRY. CANNOT RULE OUT SOMETHING ISOLD...BUT TOO LOW OF A CHANCE TO MENTION AT THIS TIME. CHANCES OF CONVECTION WILL INCREASE FROM LATE MONDAY NIGHT THROUGH TUESDAY AS SOME ASSEMBLANCE OF THE CUT OFF APPROACHES THE REGION FROM THE WEST. WILL CONTINUE CHANCES THROUGH WEDNESDAY AND THEN LEAVE THE REST OF THE FORECAST DRY FOR NOW. WE MAY WITH TIME NEED TO LINGER POPS FOR CONVECTION BEYOND WEDNESDAY. BUT GIVEN THE DEGREE OF LOW CONFIDENCE/UNCERTAINTY...PREFER TO WAIT UNTIL LATER SOLUTIONS SHOW A MORE CONSISTENT TREND DAY 6 AND BEYOND. MONDAY WILL START OFF UNSEASONABLY WARM...NOTHING NEW THIS EARLY SPRING. ONCE THE UPPER LOW BECOMES A FACTOR...TEMPERATURES SHOULD LOWER TO CLOSER TO NORMAL VALUES FOR EARLY APRIL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1253 PM CDT FRI MAR 30 2012 GENERALLY KEPT THE TAFS SIMPLE GIVEN LOW PROBABILITIES OF CONVECTION AT ANY GIVEN POINT. DEPICTED CU AND SSW WINDS GUSTY THROUGH LATE AFTERNOON. KEPT CB MENTION GOING UNTIL WINDS SHIFT AROUND LATER TONIGHT TO NNE. UPDATES MAY BE REQUIRED SHOULD CONFIDENCE INCREASE THAT CONVECTION WILL DIRECTLY AFFECT THE TERMINALS. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
147 PM EDT FRI MAR 30 2012 .Forecast Update... Issued at 145 PM EDT Mar 30 2012 Surface analysis, observations and satellite data confirm that the warm front now has lifted northward across the region. In the warm sector, south of the front, SW-NE oriented enhanced Cu field has rapidly developed. With temperatures in the upper 70s and the dewpoints in the upper 50s, this has resulted in increased atmospheric instability. Objective analysis suggests that mixed-layer CAPE values are in the 1000-1500 J/Kg range with surface LI`s now dipping below 0 degrees C. RUC proximity soundings still show a bit of CINH out to our west and that agrees well with recent high-res satellite imagery showing relatively little Cu development west of the Natcher/Green River Parkway region. Within the area of increasing CAPE, isolated convection has recently develop. Given the increasing instability and relatively weak shear, multi-cellular convection is likely to continue, but probably will remain disorganized to an extent. Pulse type hailers, and downbursts will be possible with this activity as we head into the afternoon hours. Feel that convection will likely remain fairly isolated but gradually become scattered as more instability develops. Given the SW-NE oriented Cu field along the developing horizontal convective rolls, most convection should head northeastward. Additional convection is likely to fire later this afternoon from central IL into central IN ahead of an approaching cold front. Convective activity now starting to develop across NE IN and far NW OH closer to the upper dynamics and surface low pressure system. Expect convection to backbuild to the southwest later this afternoon and then begin to sink southward through the evening hours. This line of convection will likely impact our southern Indiana counties early this evening with areas along the Ohio River and extreme northern KY getting in on the action probably in the mid-late evening hours. Main threats still look to be damaging winds and large hail. Update issued at 1155 AM EDT Mar 30 2012 Will do a quick update to freshen up the forecast a bit. Backed off on the cloud cover across the region based on the current satellite imagery. Mostly sunny skies are expected through the afternoon and this will allow good diurnal heating to take place. Some Cu may develop later this afternoon...but partly to mostly sunny skies are generally expected. Cold front is still well northwest of the region and convection is expected to fire along this front later this afternoon...mostly likely after 4PM EDT. Current temperature forecast still looks good with mid-upper 70s in the Bluegrass region and upper 70s to lower 80s elsewhere. Current 12Z data is now ingesting and we`ll address this afternoon and evening`s convective potential in the next update which will be a few hours from now. Update issued at 756 AM EDT Mar 30 2012 Going to do a quick update to add some isolated rain showers to the Bluegrass region. Surface warm front is pushing through the central sections of the forecast area this morning. As a result, a few isolated showers have continue to develop here and there across our northeastern third. These very isolated showers should continue for the next 1-2 hours and then diminish. Rest of the forecast looks on track and only minor adjustments to the remainder of the elements will be done. .Short Term (Today through Saturday)... Issued at 220 AM EDT Mar 29 2012 Convection over Iowa earlier this morning was associated with a flat progressive 500mb wave that is forecast to dig slightly across Ohio by early Saturday. At the surface, low pressure will move east across central Indiana late this afternoon. At the moment, a warm front extends from low pressure across northern Missouri southeast across western Kentucky and northern Tennessee. Well north of this surface feature, lift along an elevated boundary will allow scattered showers to move east towards southern Ohio during the pre-dawn hours. These showers will have departed the northern Bluegrass by 6 am this morning. Feel that much of today will be dry through at least mid-afternoon. As the warm front lifts north of the Commonwealth by early afternoon, southwest winds will increase as central Kentucky will find itself totally within the warm sector of the disturbance to our north. Afternoon highs will range from the upper 70s to the lower 80s today with south winds increasing this afternoon to 10 to 15 mph with some higher gusts. Expect mostly clear skies today with partly cloudy skies across southern Indiana and the northern Bluegrass. A cold front will cross into Kentucky late this evening. The 00z SPC WRF model depicts a scattered to broken line of storms developing across southern Indiana late this afternoon, then crossing the Ohio River this evening. Despite better dynamics farther northeast closer to the surface low, moderate to strong instability coupled with steep lapse rates and unidirectional winds from the west may lead to some scattered severe storms. Feel the best chance of large hail or damaging winds will lie north of interstate 64 around early to mid evening. Expect that thunderstorm intensity and coverage will decrease a bit before this weakening line reaches the Tennessee border early Saturday. Behind this front, residual low level moisture will lead to mostly cloudy skies through Saturday morning. Distinctly cooler air will invade southern Ohio behind yet another in a recent series of backdoor cold fronts. The NAM is much more aggressive than the GFS in cooling off the northern Bluegrass for Saturday, suggesting that highs will struggle to reach 60. Will trend toward the warmer GFS and forecast a wide range for high temperatures, varying from the lower 60s south of Cincinnati to the mid 70s south of Bowling Green. .Long Term (Saturday night through Thursday)... Updated at 306 AM EDT Mar 30 2012 Looks like the rest of the weekend will generally be dry as ridging develops to our west and pushes east. The front will be to our south on Saturday, and should hang up just south of the KY/TN border Saturday night, keeping any precip south of our region. By Sunday though, upper-level ridging will start to slide in from the west as surface low pressure develops over the Central Plains. Removed POPs on Sunday even though we`ll be under a northwest flow. Think the ridge will move in fast enough to help suppress any convection, or divert it to the north as a backdoor cold front associated with a northeastern CONUS low drops across the upper Ohio Valley. This should stay to our northeast as the warm front from the Central Plains` surface low stretches as far east as our CWA by Monday. Thus, have kept the mention of a slight chance of convection in for Monday, though think any storms would be attributed to warm frontal location and not just scattered in nature. After a warm and generally dry Sunday with temps in the mid 70s northeast to the low 80s southwest. From Monday afternoon on, there are significant differences with the approaching low pressure system as the GFS and GEM show a much slower solution than the Euro. Even the last hours of the NAM hint at the same thing the GFS/GEM do, and that`s cutting off an upper low over the southern Plains as the Euro is much more progressive with the cold front approach. Either way, Monday should at least be warm and moist with the warm front pushing northward across the region. Then scattered afternoon-evening convection should develop in the warm sector ahead of the approaching surface low/cold front. However, since the Euro appears as the outlier, will trend with the GFS which really slow down the low/front and fills it in, most likely bringing a longer event than previously anticipated. Thus, will slowly increase POPs from Monday afternoon through at least Tuesday evening. Even hang onto rain showers Wednesday over the southern half of the CWA as the low slowly exits the area. Went below guidance for highs Wed thinking more clouds/precip will be around than previously thought. After a warm Monday (highs in the lower 80s most everywhere), temps fall back to around 70 for highs on Tuesday with ample clouds and precip around, and into the 60s for highs for the same reason(s) on Wednesday. From Wednesday night on, system moves to our east and more ridging returns to the Lower Ohio Valley, keeping us dry through Thursday. Temperatures will moderate somewhat on Thursday. Under mostly clear skies and dry conditions, highs should still reach the upper 60s on Thursday after a chilly start to the day with morning lows in the low 40s, mainly over the east/northeast. Because of these temps this far out, may need to think about frost conditions over the Bluegrass Wed night as a result. && .Aviation (18Z TAF Issuance)... Updated at 105 PM EDT Mar 30 2012 Surface warm frontal boundary has now cleared all the terminals and southwesterly flow is picking up across the region. Partly to mostly sunny skies are expected through the early afternoon hours, but a distinct Cu field is already developing in the warm sector, south of the warm front. Can not completely rule out an isolated thunderstorm or two across the region this afternoon, but feel that the best convective potential will increase this afternoon to our northwest along an approaching frontal boundary. Scattered-broken line of storms will likely develop out ahead of this boundary and head east-southeastward across the area this evening. Feel that the best chances of convection at KSDF/KLEX will be between 30/23Z-31/06Z. Given the uncertainty in the timing, will keep VCTS going in the TAFs for now. Further south at KBWG, storms may not be an issue tonight as the line is expected to weaken due to the loss of instability as it heads southward into KY. Will maintain a VCTS group after 31/04Z. After cold frontal passage late tonight, we`ll see winds kick around to the northwest and then eventually to the northeast during the day on Saturday. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........MJ Short Term.......JSD Long Term........AL Aviation.........MJ
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1234 PM CDT FRI MAR 30 2012 .UPDATE... ISSUED AT 1233 PM CDT FRI MAR 30 2012 REFINED THE TIMING AND INTENSITY OF THE POP/WEATHER GRIDS FOR THE REST OF TODAY AND INTO TONIGHT. ADJUSTMENTS WERE ALSO MADE TO REFINE OTHER SENSIBLE WEATHER ELEMENTS...SUCH AS TEMPERATURE...DEWPOINT...WIND...SKY COVER AND RELATIVE HUMIDITY. WITH THE MANDATORY LEVEL UPPER AIR ANALYSIS...THERE WAS A MAXIMUM OF HIGHER THETA-E AIR OVER SOUTHEAST OK...NORTHERN AR...AND SOUTHEAST MISSOURI THIS MORNING...WITH A SECONDARY AREA OVER NORTHERN AND NORTHEAST ILLINOIS. THE BEST LOW LEVEL MOISTURE WAS OVER WEST KENTUCKY...SOUTHEAST ILLINOIS AND SOUTHWEST INDIANA. THE 12KM NAM-WRF AND 3KM HRRR NUMERICAL MODEL MASS/INSTABILITY/RADAR REFLECTIVITY FIELDS SUGGEST THAT THE NORTHERN INDIANA CONVECTION AND NEWLY MINTED CENTRAL KENTUCKY CONVECTION SHOULD GRADUALLY BUILD WESTWARD WITH TIME. THE 0-3/3-6KM NAM-WRF BULK SHEAR REMAINS LOW /15-25 KNOTS/...SO SIGNIFICANT STORM ORGANIZATION MAY NOT BE IN THE CARDS FOR THE AREA. HOWEVER...SHARP LAPSE RATES AND DECENT CAPE/DOWNDRAFT CAPE SUGGEST THE POTENTIAL THAT GOOD UPDRAFTS WILL WARRANT THE MENTION OF AT LEAST SMALL HAIL AND GUSTY WINDS IN THE GRIDDED FORECAST THIS AFTERNOON AND INTO THE EARLY EVENING HOURS. AT THIS TIME...FOCUSED THIS MENTION OF HAIL/WIND IN THE SCATTERED THUNDERSTORM COVERAGE AREA. THE NAM-WRF/GFS/RUC APPEARED TO INITIALIZE BETTER WITH INSTABILITY /LIFTED INDEXES/ AND PRECIPITABLE WATER FROM THE GOES SOUNDER IMAGERY VERSUS THE REST OF THE MODEL GUIDANCE THIS MORNING. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 1233 PM CDT FRI MAR 30 2012 IN LINE WITH THE MIDNIGHT SHIFT ADJUSTMENT FOR POPS/WEATHER TONIGHT INTO SATURDAY...ADJUSTED AND SLIGHTLY INCREASED RAIN CHANCES MAINLY OVER SOUTHEAST MISSOURI. GIVEN THE STRONGER DRY AIR ADVECTION AHEAD OF THE FRONTAL BOUNDARY ON SATURDAY...KEPT RAIN CHANCES OUT OF A VAST MAJORITY OF SOUTHERN ILLINOIS AND WEST KENTUCKY AND ALL OF SOUTHWEST INDIANA. RIDGING ON SUNDAY STILL REMAINS DOMINANT...SO LOW TO MIDDLE 80S AND LIMITED CLOUD COVER REMAIN ON TARGET IN THE FORECAST. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 332 AM CDT FRI MAR 30 2012 HIGH PRESSURE AT THE SURFACE AND ALOFT WILL KEEP THE REGION DRY SUNDAY AND SUNDAY NIGHT. BEYOND THAT MODELS NOT IN THE BEST AGREEMENT IN THE WAY THEY HANDLE THE STORM SYSTEM TO AFFECT THE AREA BEGINNING EARLY NEXT WEEK. AS THE NEXT STORM SYSTEM MOVES OUT OF THE PLAINS...PRECIP CHANCES MAKE THEIR WAY BACK INTO THE FORECAST ON MONDAY. HARD TO SAY HOW MUCH COVERAGE THERE WILL BE ON MONDAY. MODELS SHOW DECENT RIDGING ALOFT DIRECTLY OVER OUR CWA...BUT ALSO SHOW A SFC TROF AND WARM FRONT OVER THE NORTHEAST SECTIONS ASSOCIATED WITH THE APPROACHING STORM SYSTEM. SHOWER AND THUNDERSTORM CHANCES APPEAR TO BE GREATEST MONDAY NIGHT AND TUESDAY AS THE AFOREMENTIONED SYSTEM ACTUALLY MOVES ACROSS THE AREA. NOT NEARLY AS CONFIDENT FOR PRECIP CHANCES TUESDAY NIGHT AND WEDNESDAY. DURING THOSE PERIODS THE ECMWF IS MORE PROGRESSIVE AND SHOWS HIGH PRESSURE OVERSPREADING THE AREA IN THE WAKE OF THE STORM SYSTEM WHILE THE GFS WINDS UP THE UPPER LOW ASSOCIATED WITH THIS SYSTEM AND MOVES IT SLOWLY ACROSS THE SOUTHERN SECTIONS OF THE CWA DURING THE SAME PERIOD. DECIDED TO GO WITH SOMEWHAT OF A BLEND BUT WITH A LEAN TOWARD THE GFS SOLUTION. IN THE WAKE OF THIS SYSTEM SURFACE HIGH PRESSURE OVERSPREADING THE AREA WILL KEEP THINGS DRY WITH TEMPERATURES CLOSER TO NORMAL FOR THIS TIME OF YEAR. BETWEEN A STORM SYSTEM DEVELOPING OVER THE PLAINS AND THE DEPARTING SURFACE HIGH...SOUTHERLY FLOW WILL ADVECT ENOUGH MOISTURE BACK INTO REGION TO WARRANT SHOWER AND THUNDERSTORM CHANCES ON MONDAY AND MONDAY NIGHT. A FEW SHOWERS ARE POSSIBLE OVER THE NORTHEAST SECTIONS OF THE CWA ON TUESDAY IN THE WRAP AROUND MOISTURE. SURFACE HIGH PRESSURE IN THE WAKE OF THE FRONT AND WEAK RIDGING ALOFT SHOULD KEEP THE REGION DRY AND SLIGHTLY COOLER THROUGH THE END OF THE PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 705 AM CDT FRI MAR 30 2012 VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS. SOUTH WINDS WILL PICK UP THIS MORNING TO 10 TO 15 KNOTS...WITH GUSTS OF 15 TO 20 KNOTS AT TIMES. SCATTERED CUMULUS DEVELOPMENT IS EXPECTED BY LATE MORNING INTO THE AFTERNOON. ISOLATED THUNDERSTORMS WILL DEVELOP DURING THE MID TO LATE AFTERNOON AHEAD OF A SOUTHWARD ADVANCING COLD FRONT...SO INCLUDED A CB MENTION IN THE TAFS. THE STORMS SHOULD DIMINISH DURING THE EVENING AS WINDS SUBSIDE. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...SMITH SHORT TERM...SMITH LONG TERM....JP AVIATION...RJP
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
425 PM EDT FRI MAR 30 2012 .SYNOPSIS... LOW PRESSURE MOVES EAST FROM THE OHIO VALLEY TONIGHT AND ACROSS THE AREA ON SATURDAY. THIS WILL PUSH A COLD FRONT ACROSS THE REGION SATURDAY AFTERNOON. HIGH PRESSURE WILL BE OVER THE AREA ON SUNDAY. A SECOND COLD FRONT WILL MOVE THROUGH THE AREA FROM THE NORTH ON MONDAY. && .NEAR TERM /THROUGH SATURDAY/... TRICKY FORECAST TONIGHT AS SEVERAL DISTURBANCES IMPACT THE AREA. ONCE DISTURBANCE HANDLED WELL BY THE HRRR IS CAUSING A FEW SHOWERS ACROSS THE DELMARVA AND NORTHERN AREAS LATE THIS AFTERNOON AND EVENING. THIS IS ALONG A DEVELOPING UPPER LEVEL WARM FRONT WHICH WILL QUICKLY MOVE NORTH OF THE AREA. THE NEXT SYSTEM IS AN UPPER DISTURBANCE OVER THE SOUTHEAST WHICH WILL MOVE ACROSS TO THE SOUTH OF THE AREA TONIGHT AND EARLY ON SATURDAY. THIS IS CAUSING AN AREA OF CONVECTION TO DEVELOP TO THE SOUTH OF THE AREA. HOW FAR NORTH THIS CONVECTION DEVELOPS IS QUITE VARIED ON THE MODEL FORECAST. THE VAST MAJORITY KEEP THE SOUTHERN CONVECTION SOUTH OF THE VIRGINIA NORTH CAROLINA LINE. HOWEVER COULD SEE IT MOVE OVER EXTREME SOUTHEASTERN VIRGINIA AROUND SUNRISE. THE OTHER SYSTEM IN THE OHIO VALLY HAS A SURFACE LOW PRESSURE SYSTEM ASSOCIATED WITH IT OVER OHIO. THIS LOW WILL MOVE EAST AND THEN SOUTHEAST ACROSS THE AREA ON SATURDAY. THIS WILL BRING SOME SHOWERS TO THE NORTHWEST SECTIONS LATER TONIGHT. ON SATURDAY SEVERAL MODELS ARE SHOWING CONVECTION DEVELOPING AHEAD OF THIS SYSTEM DURING THE AFTERNOON MAINLY SOUTHEAST OF THE RICHMOND AREA. LOOKING AT BUFKIT THE MAIN QUESTION BECOMES HOW FAST DRIER AIR CAN WORK IN AND CUT OFF THE CONVECTIVE POTENTIAL. ALL MODELS DO HAVE SOME FORCING WITH THE SYSTEM. FOR NOW WENT WITH CHANCE POPS. TEMPERATURES TONIGHT WILL ONLY DROP INTO THE 50S MOST AREAS ON DEVELOPING SOUTHWEST WINDS. ON SATURDAY THE LIMITING FACTOR ON TEMPERATURES WILL BE THE CLOUDS BUT STILL THINK MANY INLAND AREAS WILL BE IN THE 70S. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... BY SATURDAY NIGHT AND ON SUNDAY THE AREA IS BETWEEN SYSTEMS WITH PLENTY OF DRY AIR SO SKIES WILL CLEAR. ON SUNDAY WILL HAVE SOME COLD AIR ADVECTION ALOFT BUT TEMPERATURES STILL ABOVE NORMAL WITH DOWNSLOPE NORTHWEST FLOW AND PLENTY OF SUNSHINE. BY SUNDAY NIGHT THE NEXT FRONT APPROACHES FROM THE NORTHWEST. AGAIN THE MODELS HAVE DIFFERENCES ON THE AMOUNT OF PRECIPITATION ASSOCIATED WITH THIS FRONT. WILL LEAN TOWARD DRIER MODELS SUCH AS CANADIAN AND GFS. STILL HAVE SLIGHT CHANCE POPS LATE SUNDAY NIGHT AND MONDAY WITH THE HIGHEST POPS TO THE EASTERN SECTIONS. THE NAM DOES NOT PUSH THE FRONT THROUGH BUT WILL BASE TEMPERATURES ON HAVING THE FRONT TO THE SOUTH. AGAIN STILL ABOVE NORMAL MOST INLAND AREAS BUT WITH SOME EAST COMPONENT TO THE WINDS AREAS OVER THE DELMARVA AND ALONG THE COAST WILL REMAIN IN THE 60S FOR HIGHS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... THE MID AND UPPER LEVEL LONGWAVE PATTERN CONTINUES TO APPEAR MORE AMPLIFIED AND NORTHERN STREAM DOMINATED DURING THE EXTENDED PERIOD FROM MONDAY NIGHT THROUGH FRIDAY. GIVEN THIS...TEMPERATURES WERE LOWERED A FEW DEGREES FOR TUESDAY AS A TROUGH OVER MARITIME CANADA DRIVES NW FLOW FROM THE MID ATLANTIC TO NEW ENGLAND...BUT THE IDEA OF A WARMING TREND OVER MONDAY REMAINS REASONABLE AS THICKNESS VALUE ARE EXPECTED TO RISE. THE AMPLIFICATION IN THE PATTERN APPEARS TO DELAY THE NEXT COLD FRONT TO TUESDAY NIGHT AND WEDNESDAY. MOISTURE APPEARS RATHER LIMITED AS NORTHERN STREAM ENERGY KEEPS DEEPER MOISTURE SOUTH OF THE LOCAL AREA. MORE SEASONAL TEMPERATURES ARE EXPECTED BY THE END OF THE WEEK AS CANADIAN HIGH PRESSURE BUILDS IN BEHIND THE AFOREMENTIONED COLD FRONT. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... VFR CONDS ACROSS THE REGION AT 18Z BUT AN AREA OF RAIN ASSOC WITH A LOW PRES AREA IS MOVG THRU NOVA AND SRN MD. AT THE PRESENT SPEED THE RAIN WILL LIKELY MOVE ONTO EASTERN SHORE MD AROUND 19Z AND THEN AFFECT SBY. TEMPO MVFR CIGS/VSBY PSBL WITH THIS PRECIP THRU THE AFTN. A WARM FRONT WILL MOVE N FROM THE CAROLINAS THIS EVENING AND TONIGHT. LOW CLOUDS AND -RA WILL DEVELOP IN ADVANCE OF THE FRONT DURING THE OVERNIGHT HOURS. TIMING IS DIFFICULT BUT THINK RAIN WILL LIKELY AFFECT NE NC AND SRN VA FROM AFTER MIDNIGHT TO MID MORNING ON SAT. THE WARM FRONT WILL BE NORTH OF OUR CWA EARLY SAT. THEN A COLD FRONT IS EXPECTED TO APPROACH SAT AFTN/EVENING. THIS WILL BRING ANOTHER CHC OF RAIN/TSTMS. THE FRONT CLEARS THE REGION EARLY SAT EVENING. HIGH PRES BUILDS INTO THE REGION SUN AND MON WITH EXPECTED GOOD VFR CONDS. && .MARINE... SURFACE HIGH PRESSURE MOVES OFF THE COAST TONIGHT AS LOW PRESSURE AND AN ASSOCIATED COLD FRONT APPROACH FROM THE WEST. THIS COLD FRONT CROSSES THE MID ATLANTIC COAST N-S DURING THE LATE AFTERNOON AND EARLY EVENING SATURDAY. A MODEST NORTHERLY SURGE IS EXPECTED IN THE WAKE OF THE COLD FRONT. WIND SPEEDS SHOULD BE AROUND 20-25KT AND THIS SHOULD ALSO PUSH SEAS TO AROUND 5FT. GIVEN THIS...SCA FLAGS HAVE BEEN RAISED FOR ALL AREAS BEGINNING N-S SATURDAY AFTERNOON AND EVENING...AND THEN ENDING N-S EARLY SUNDAY MORNING. HIGH PRESSURE BRIEFLY BUILDS IN SUNDAY BEFORE MOVING OFF THE COAST AS ANOTHER LOW PRESSURE SYSTEM MOVES OFF THE NEW ENGLAND COAST SUNDAY NIGHT AND SUBSEQUENTLY DRAGS A COLD FRONT ACROSS THE MID ATLANTIC COAST. A NORTHERLY SURGE WILL FOLLOW MONDAY MORNING...BUT THIS APPEARS SUB-SCA AT THIS TIME. HIGH PRESSURE THEN PREVAILS THROUGH TUESDAY BEFORE ANOTHER LOW PRESSURE SYSTEM ARRIVES MIDWEEK. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM SATURDAY TO 4 AM EDT SUNDAY FOR ANZ632-634. SMALL CRAFT ADVISORY FROM 7 PM SATURDAY TO 7 AM EDT SUNDAY FOR ANZ633. SMALL CRAFT ADVISORY FROM 4 PM SATURDAY TO 4 AM EDT SUNDAY FOR ANZ630-631. SMALL CRAFT ADVISORY FROM 4 PM SATURDAY TO 7 AM EDT SUNDAY FOR ANZ650-652-654. SMALL CRAFT ADVISORY FROM 7 PM SATURDAY TO 10 AM EDT SUNDAY FOR ANZ656-658. && $$ SYNOPSIS...JAB NEAR TERM...JAB SHORT TERM...JAB LONG TERM...AJZ AVIATION...JEF MARINE...AJZ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
336 PM EDT FRI MAR 30 2012 .SYNOPSIS... LOW PRESSURE MOVES EAST FROM THE OHIO VALLEY TONIGHT AND ACROSS THE AREA ON SATURDAY. THIS WILL PUSH A COLD FRONT ACROSS THE REGION SATURDAY AFTERNOON. HIGH PRESSURE WILL BE OVER THE AREA ON SUNDAY. A SECOND COLD FRONT WILL MOVE THROUGH THE AREA FROM THE NORTH ON MONDAY. && .NEAR TERM /THROUGH SATURDAY/... TRICKY FORECAST TONIGHT AS SEVERAL DISTURBANCES IMPACT THE AREA. ONCE DISTURBANCE HANDLED WELL BY THE HRRR IS CAUSING A FEW SHOWERS ACROSS THE DELMARVA AND NORTHERN AREAS LATE THIS AFTERNOON AND EVENING. THIS IS ALONG A DEVELOPING UPPER LEVEL WARM FRONT WHICH WILL QUICKLY MOVE NORTH OF THE AREA. THE NEXT SYSTEM IS AN UPPER DISTURBANCE OVER THE SOUTHEAST WHICH WILL MOVE ACROSS TO THE SOUTH OF THE AREA TONIGHT AND EARLY ON SATURDAY. THIS IS CAUSING AN AREA OF CONVECTION TO DEVELOP TO THE SOUTH OF THE AREA. HOW FAR NORTH THIS CONVECTION DEVELOPS IS QUITE VARIED ON THE MODEL FORECAST. THE VAST MAJORITY KEEP THE SOUTHERN CONVECTION SOUTH OF THE VIRGINIA NORTH CAROLINA LINE. HOWEVER COULD SEE IT MOVE OVER EXTREME SOUTHEASTERN VIRGINIA AROUND SUNRISE. THE OTHER SYSTEM IN THE OHIO VALLY HAS A SURFACE LOW PRESSURE SYSTEM ASSOCIATED WITH IT OVER OHIO. THIS LOW WILL MOVE EAST AND THEN SOUTHEAST ACROSS THE AREA ON SATURDAY. THIS WILL BRING SOME SHOWERS TO THE NORTHWEST SECTIONS LATER TONIGHT. ON SATURDAY SEVERAL MODELS ARE SHOWING CONVECTION DEVELOPING AHEAD OF THIS SYSTEM DURING THE AFTERNOON MAINLY SOUTHEAST OF THE RICHMOND AREA. LOOKING AT BUFKIT THE MAIN QUESTION BECOMES HOW FAST DRIER AIR CAN WORK IN AND CUT OFF THE CONVECTIVE POTENTIAL. ALL MODELS DO HAVE SOME FORCING WITH THE SYSTEM. FOR NOW WENT WITH CHANCE POPS. TEMPERATURES TONIGHT WILL ONLY DROP INTO THE 50S MOST AREAS ON DEVELOPING SOUTHWEST WINDS. ON SATURDAY THE LIMITING FACTOR ON TEMPERATURES WILL BE THE CLOUDS BUT STILL THINK MANY INLAND AREAS WILL BE IN THE 70S. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... BY SATURDAY NIGHT AND ON SUNDAY THE AREA IS BETWEEN SYSTEMS WITH PLENTY OF DRY AIR SO SKIES WILL CLEAR. ON SUNDAY WILL HAVE SOME COLD AIR ADVECTION ALOFT BUT TEMPERATURES STILL ABOVE NORMAL WITH DOWNSLOPE NORTHWEST FLOW AND PLENTY OF SUNSHINE. BY SUNDAY NIGHT THE NEXT FRONT APPROACHES FROM THE NORTHWEST. AGAIN THE MODELS HAVE DIFFERENCES ON THE AMOUNT OF PRECIPITATION ASSOCIATED WITH THIS FRONT. WILL LEAN TOWARD DRIER MODELS SUCH AS CANADIAN AND GFS. STILL HAVE SLIGHT CHANCE POPS LATE SUNDAY NIGHT AND MONDAY WITH THE HIGHEST POPS TO THE EASTERN SECTIONS. THE NAM DOES NOT PUSH THE FRONT THROUGH BUT WILL BASE TEMPERATURES ON HAVING THE FRONT TO THE SOUTH. AGAIN STILL ABOVE NORMAL MOST INLAND AREAS BUT WITH SOME EAST COMPONENT TO THE WINDS AREAS OVER THE DELMARVA AND ALONG THE COAST WILL REMAIN IN THE 60S FOR HIGHS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... LATEST NUMERICAL MODEL GUIDANCE IS SUGGESTING SOMEWHAT MORE OF AN AMPLIFIED MID AND UPPER LEVEL PATTERN FOR THE MEDIUM RANGE PERIOD. THIS WOULD ENHANCE NW FLOW OVER THE MID ATLANTIC AND NORTHEAST SUNDAY NIGHT AND INTO MONDAY...WHICH LOCALLY WOULD ALLOW A WEAK BACKDOOR FRONT TO DROP INTO THE FORECAST AREA. NO SIGNIFICANT WX EXPECTED WITH THIS...BUT THE POTENTIAL EXISTS FOR A 20+ DEGREE TEMP DIFFERENCE ACROSS THE RGN. TMPS 65-70 EASTERN SHORE TO U70S- L80S W OF THE BAY (NOT OUT OF THE QSTN TO SEE OXB DROP INTO THE 50S BY LATE IN THE DAY AS THE FLOW TURNS E). TUESDAY SHOULD REMAIN MILD AHEAD OF AN APRCHG COLD FRONT. POPS WERE INCREASED TO CHANCE FOR TUESDAY AFTERNOON EVENING...BUT THIS FRONT COULD END UP BEING SLOWER IF THE AFOREMENTIONED AMPLIFICATION OCCURS. TEMPERATURES WILL BE LOWER BEHIND THE FRONT...BUT STILL ON THE WARM SIDE OF SEASONAL AVERAGES (LOW/MID 70S). && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... VFR CONDS ACROSS THE REGION AT 18Z BUT AN AREA OF RAIN ASSOC WITH A LOW PRES AREA IS MOVG THRU NOVA AND SRN MD. AT THE PRESENT SPEED THE RAIN WILL LIKELY MOVE ONTO EASTERN SHORE MD AROUND 19Z AND THEN AFFECT SBY. TEMPO MVFR CIGS/VSBY PSBL WITH THIS PRECIP THRU THE AFTN. A WARM FRONT WILL MOVE N FROM THE CAROLINAS THIS EVENING AND TONIGHT. LOW CLOUDS AND -RA WILL DEVELOP IN ADVANCE OF THE FRONT DURING THE OVERNIGHT HOURS. TIMING IS DIFFICULT BUT THINK RAIN WILL LIKELY AFFECT NE NC AND SRN VA FROM AFTER MIDNIGHT TO MID MORNING ON SAT. THE WARM FRONT WILL BE NORTH OF OUR CWA EARLY SAT. THEN A COLD FRONT IS EXPECTED TO APPROACH SAT AFTN/EVENING. THIS WILL BRING ANOTHER CHC OF RAIN/TSTMS. THE FRONT CLEARS THE REGION EARLY SAT EVENING. HIGH PRES BUILDS INTO THE REGION SUN AND MON WITH EXPECTED GOOD VFR CONDS. && .MARINE... WINDS HAVE SUBSIDED A LITTLE AS A SFC HIGH MOVD OVER THE WTRS AND IS CONTINUING EAST. THIS WILL CAUSE SOME OF THE WINDS TO SHFT MORE SE THIS AFTN. SPDS SHOULD AVG 10-15 KTS DURING THE AFTN WITH SOME ISOLD GUST TO 20 KT PSBL BY EARLY EVENING. A FRONTL BNDRY OVER THE CAROLINAS WILL MOVE NORTH AS A WARM FRONT THIS AFTN AND EVENING AND WILL PASS OVER THE WTRS TONIGHT. EXPECT SOME INCREASE IN WND SPDS AS THE FRONT MOVES NORTH AND THERE IS A CHC OF MINIMAL SCA BY TONIGHT. LO PRES AND ASSOCIATED COLD FRNT CROSS THE MID ATLANTIC SAT...WITH A GOOD CHANCE OF SCA CONDS OVER ALL WATERS (ESPECIALLY LWR BAY) SAT EVNING/NGT FOLLOWING THE FROPA. WILL HOLD OFF ON A 4TH PERIOD ADVISORY ATTM DUE TO UNCERTAINTIES WITH THE TIMING AND STRENGTH OF THE SURGE THIS FAR OUT IN TIME. ASIDE FROM LINGERING 5 FT SEAS ON SUN...SUB- SCA CONDS EXPECTED AS HI PRES BUILDS IN FROM THE W. FOLLOWING ANOTHER COLD FROPA EARLY MON...HI PRES AND QUIET WX RETURNS OVER THE WATERS LATE MON/TUE. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM SATURDAY TO 4 AM EDT SUNDAY FOR ANZ632-634. SMALL CRAFT ADVISORY FROM 7 PM SATURDAY TO 7 AM EDT SUNDAY FOR ANZ633. SMALL CRAFT ADVISORY FROM 4 PM SATURDAY TO 4 AM EDT SUNDAY FOR ANZ630-631. SMALL CRAFT ADVISORY FROM 4 PM SATURDAY TO 7 AM EDT SUNDAY FOR ANZ650-652-654. SMALL CRAFT ADVISORY FROM 7 PM SATURDAY TO 10 AM EDT SUNDAY FOR ANZ656-658. && $$ SYNOPSIS...JAB NEAR TERM...JAB SHORT TERM...JAB LONG TERM...AJZ AVIATION...JEF MARINE...JEF
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
309 PM EDT FRI MAR 30 2012 .SYNOPSIS... LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL PASS THROUGH THE REGION TONIGHT INTO SATURDAY. HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY NIGHT BEFORE MOVING OFF THE COAST SUNDAY. ANOTHER COLD FRONT WILL PASS THROUGH THE REGION SUNDAY NIGHT FOLLOWED BY HIGH PRESSURE EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... WARM ADVECTION HAS LED TO PLENTY OF CLOUDS AND ALSO SOME SHOWERS ACROSS THE CWA THIS AFTERNOON. HRRR AND WRF-ARW HAVE DONE A DECENT JOB IN HANDLING THIS ACTIVITY...AND MOVE THE SHOWERS EAST OF THE CHESAPEAKE BAY AREA THROUGH 20Z-21Z. AFTER THEN...CLOUD COVER WILL HANG ON ALTHOUGH THERE MAY BE A RELATIVE LULL IN SHOWERS FOR A FEW HOURS FOR THE REST OF THE AFTERNOON /SAVE FOR AN ISOLATED SHOWER ACROSS THE HIGHLANDS/. ADDITIONAL ACTIVITY WILL DEVELOP ACROSS OHIO/WESTERN PA/WEST VIRGINIA...AND WILL MOVE EAST THIS EVENING. ISENTROPIC LIFT IS ALSO FORECAST TO STRENGTHEN ESPECIALLY ACROSS THE NORTHERN PORTION OF THE CWA AS A WARM FRONT APPROACHES FROM THE SOUTH AND LOW PRESSURE APPROACHES FROM THE WEST. HAVE HIGHEST POPS /LIKELY TO CATEGORICAL/ ACROSS NORTHERN AND WESTERN PORTIONS OF THE CWA TONIGHT WITHIN THE BEST LIFT...TAPERING TO CHANCE POPS ACROSS THE SOUTHERN PORTION OF THE CWA. THIS LEANS TOWARD POPS FROM THE SREFS. HAVE ALSO INCLUDED ISOLATED THUNDERSTORMS ACROSS THE WESTERN PORTION OF THE CWA FOR ANY ONGOING CONVECTION TO THE WEST MAKING IT INTO THE CWA. WHILE THE ENVIRONMENT WILL BE LESS UNSTABLE THAN AREAS TO THE WEST...NAM KEEPS SOME ELEVATED INSTABILITY ACROSS THE CWA. LOW PRESSURE /AND ASSOCIATED FRONT/ MOVES ACROSS THE CWA EARLY SATURDAY MORNING. UNTIL IT MOVES OFF THE COAST...WILL KEEP POPS ACROSS THE CWA ESPECIALLY NEAR THE BAY. MUCH OF THE AFTERNOON SHOULD DRY OUT...HOWEVER CLEARING WILL LAG A BIT AND CLOUDS MAY NOT BREAK UNTIL EVENING. TEMPERATURE GUIDANCE WAS GENERALLY SIMILAR AND FOLLOWED TONIGHT. GUIDANCE WAS DIFFERENT BY UP TO 10 DEG F FOR MAX T ON SATURDAY. FOLLOWED THE MET MOS WHICH KEEPS CLOUDS THROUGH THE AFTERNOON VERSUS THE MAV MOS WHICH BREAKS CLOUDS SOONER. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY NIGHT BEHIND A COLD FRONT...RESULTING IN DRY AND SEASONABLY CHILLY CONDITIONS. MIN TEMPS WILL RANGE FROM THE MID 30S ACROSS NORTHERN MARYLAND TO THE LOWER AND MIDDLE 40S IN LOWER SOUTHERN MARYLAND INTO THE VIRGINIA PIEDMONT. PATCHY FROST IS POSSIBLE MAINLY IN RURAL AREAS AND SHELTERED VALLEYS LATE SATURDAY NIGHT ACROSS NORTHERN MARYLAND INTO THE EASTERN PANHANDLE OF WEST VIRGINIA. SURFACE HIGH PRESSURE WILL MOVE OFF THE COAST SUNDAY ALLOWING FOR RETURN FLOW TO DEVELOP. THE RETURN FLOW WILL USHER IN MILD CONDITIONS WITH MAX TEMPS RANGING FROM THE MID 60S ACROSS NORTHEASTERN MARYLAND TO THE MIDDLE AND UPPER 70S ACROSS CENTRAL VIRGINIA. A COLD FRONT WILL APPROACH THE REGION LATE SUNDAY FROM THE NORTH. THE FRONT SHOULD REMAIN FAR ENOUGH TO THE NORTH FOR DRY CONDITIONS ALONG WITH SOME SUNSHINE ACROSS MOST AREAS. HOWEVER...A COUPLE SHOWERS MAY REACH NORTHERN MARYLAND/EASTERN WEST VIRGINIA LATER IN THE AFTERNOON. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... UPPER-LEVEL LOW PRESSURE WILL DEVELOP OFF THE NEW ENGLAND COAST SUNDAY NIGHT INTO EARLY NEXT WEEK. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL PASS THROUGH THE REGION SUNDAY NIGHT. SHOWERS ARE POSSIBLE WITH THE FRONTAL PASSAGE. HIGH PRESSURE WILL BUILD IN BEHIND THE COLD FRONT FOR MONDAY THROUGH MONDAY NIGHT...BRINGING DRY AND SEASONABLE CONDITIONS. HIGH PRESSURE WILL MOVE OFF THE COAST TUESDAY AND ANOTHER COLD FRONT WILL PASS THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. SHOWERS AND THUNDERSTORMS ARE POSSIBLE WITH THE FRONTAL PASSAGE. THE BEST CHANCE FOR T-STORMS WILL LIKELY BE ACROSS THE WESTERN PORTION OF THE CWA WHERE THERE WILL BE MORE INSTABILITY. SURFACE HIGH PRESSURE WILL LIKELY BUILD OVERHEAD WHILE THE COLD FRONT MOVES TO OUR SOUTH LATE IN THE WEEK. HOWEVER...THERE IS STILL A HIGH DEGREE OF UNCERTAINTY TO THE EXACT POSITION OF THE FRONT DURING THIS TIME. SHOULD THE FRONT BE A BIT FARTHER NORTH...THEN UNSETTLED CONDITIONS ARE POSSIBLE. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... MID LEVEL CLOUD DECK WILL LOWER THIS EVENING WITH SOUTHEAST FLOW IN PLACE AND LOW PRESSURE APPROACHING FROM THE WEST. GFS MOS/LAMP ARE AGGRESSIVE IN BRINGING IN IFR/LIFR TO ALL TERMINALS OVERNIGHT/SATURDAY MORNING. NAM MOS BRINGS IN IFR AT BWI/MTN AS WELL BUT NOT THE OTHER TERMINALS. TAFS LEAN MORE TOWARD THIS SOLUTION. BELIEVE WARM FRONT WILL MOVE NORTH TOWARD/PAST THE IAD-DCA TERMINALS OVERNIGHT. BWI/MTN AND ALSO MRB TO THE NORTH OF THE BOUNDARY ARE EXPECTED TO DETERIORATE INTO IFR WITH SHOWERS MOVING ACROSS OVERNIGHT/EARLY SATURDAY. TO THE SOUTH OF THE BOUNDARY...HAVE SIDED WITH MVFR WITH LOWER CONFIDENCE IN IFR. SREFS PROBS FOR IFR SUPPORT THE IFR INCLUSION AT MRB/BWI/MTN AND NOT THE FURTHER SOUTH TERMINALS. ALL RESTRICTIONS WILL IMPROVE BY MID-MORNING SATURDAY AS WINDS SHIFT TO THE NORTHWEST WITH LOW PRESSURE MOVING OFF THE COAST. DESPITE THIS...NAM MOS ACTUALLY KEEPS IFR AT BWI/MTN HOWEVER BELIEVE THIS IS OVERDONE. HIGH PRESSURE WILL BUILD OVER THE TERMINALS SATURDAY NIGHT...BRINGING VFR CONDITIONS MOST OF THE TIME. PATCHY BR MAY CAUSE VSBYS TO APPROACH MVFR LEVELS EARLY SUNDAY MORNING. A SOUTHERLY FLOW WILL INCREASE SUNDAY AS HIGH PRESSURE MOVES OFFSHORE. VFR CONDITIONS ARE EXPECTED. THE COLD FRONT WILL PASS THROUGH SUNDAY NIGHT BEFORE HIGH PRESSURE BUILDS OVERHEAD EARLY NEXT WEEK. VFR CONDITIONS ARE EXPECTED MOST OF THE TIME. ANOTHER COLD FRONT WILL IMPACT THE TERMINALS DURING THE MIDDLE PORTION OF NEXT WEEK. && .MARINE... SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THIS EVENING. IT LOOKS MARGINAL...BUT GUIDANCE SUGGESTS SOUTHEAST WINDS INCREASING THIS EVENING ACROSS THE LOWER TIDAL POTOMAC/MD BAY AREA. HIGHER PROBABILITY SMALL CRAFT ADVISORY LOOKS TO BE SATURDAY AFTERNOON AS DEPARTING LOW PRESSURE MOVES OFF THE COAST AND WINDS TURN TO THE NORTHWEST. HIGH PRESSURE WILL BUILD OVER THE WATERS SATURDAY NIGHT. NORTH-NORTHEAST WINDS AHEAD OF THE HIGH WILL GUST PAST SCA CRITERIA. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE WATERS SATURDAY EVENING...AND FOR THE MIDDLE PORTION OF THE BAY AND LOWER TIDAL POTOMAC RIVER OVERNIGHT. WINDS WILL DIMINISH TOWARD MORNING AS THE HIGH BUILDS OVERHEAD. HIGH PRESSURE WILL MOVE OFF THE COAST SUNDAY AND A SOUTHERLY RETURN FLOW WILL INCREASE. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS SUNDAY AFTERNOON. A COLD FRONT WILL PASS THROUGH THE WATERS SUNDAY NIGHT AND HIGH PRESSURE WILL BUILD OVERHEAD EARLY NEXT WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS AHEAD OF THE COLD FRONT SUNDAY EVENING AND AGAIN FOR BEHIND THE COLD FRONT SUNDAY NIGHT AND MONDAY. HIGH PRESSURE WILL MOVE OFF THE COAST TUESDAY AND ANOTHER COLD FRONT MAY IMPACT THE WATERS DURING THE MIDDLE PORTION OF NEXT WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS DURING THE MIDDLE PORTION OF NEXT WEEK. && .TIDES/COASTAL FLOODING... WILL HAVE TO CONTINUE TO MONITOR WATER LEVELS FOR THE TONIGHT HIGH TIDE CYCLE. FORTUNATELY...ASTRONOMICAL TIDES ARE RELATIVELY LOW CONSIDERING THE LUNAR CYCLE. ANOMALIES NEAR 1 FT AT ANNAPOLIS CAUSED A WATER LEVEL OF NEAR 2.2 FT MLLW DURING HIGH TIDE AROUND NOON. ANOMALIES MAY GO UP A LITTLE MORE THIS EVENING...HOWEVER THE EVENING HIGH TIDE IS ALSO THE LOWER OF THE TWO. THEREFORE...CURRENT FORECAST IS FOR WATER LEVELS TO REMAIN JUST UNDER MINOR TIDAL FLOODING THRESHOLDS. HOWEVER...IF ANOMALIES INCREASE MORE/FASTER THEN SENSITIVE LOCATIONS SUCH AS ANNAPOLIS COULD REACH MINOR TIDAL FLOODING THRESHOLDS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT TONIGHT FOR ANZ531>534-537>543. SMALL CRAFT ADVISORY FROM 1 PM TO 10 PM EDT SATURDAY FOR ANZ530-531-535-536-538-539. SMALL CRAFT ADVISORY FROM 1 PM SATURDAY TO 6 AM EDT SUNDAY FOR ANZ532>534-537-540>543. && $$ SYNOPSIS...BJL/BPP NEAR TERM...BPP SHORT TERM...BJL LONG TERM...BJL AVIATION...BJL/BPP MARINE...BJL/BPP TIDES/COASTAL FLOODING...BPP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
131 PM EDT FRI MAR 30 2012 .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 423 AM EDT FRI MAR 30 2012 BROAD AREA OF SHOWERS STRETCHING FROM THE ARROWHEAD OF MN THROUGH WRN UPPER MI...WRN TWO THIRDS OF WI AND INTO ERN IOWA AT 07Z. OVER THE ARROWHEAD OF MN AND INTO WRN UPPER MI...SHOWERS HAVE BEEN MAINLY IN THE FORM OF SNOW. RECENT WEBCAM IMAGES IN IRONWOOD SHOW A DUSTING OF SNOW ON THE GROUND OVER THE LAST HOUR OR SO. FARTHER SOUTH AND WEST...STARTING TO SEE A TRANSITION TO RAIN AS THE NOSE OF WARM AIR AND DRY AIR ALOFT ARE STARTING TO TURN THE PCPN BACK TO RAIN OVER NW WI. THIS IS ALL RAIN THROUGH THE REST OF WI AND INTO IOWA...WHERE CONVECTION DEVELOPED DURING THE EVENING AND HAS SPREAD NE. THE PCPN IS ASSOCIATED WITH A SHORTWAVE MOVING THROUGH THE CNTRL/NRN PLAINS STATES...WHILE A SFC LOW IS TRACKING THROUGH NRN MO AND SRN IOWA. PCPN FOR THIS MORNING IS THE MAIN FEATURE OF CONCERN FOR THE SHORT TERM FORECAST. THE NRN PART OF THE PCPN AREA IS THE INITIAL AREA OF CONCERN. THIS SHOULD CONTINUE TO THE E OVER THE NEXT SEVERAL HOURS...BUT WITH THE MID-LOW LVL DRY AIR IN PLACE...EXPECT THIS TO EAT AWAY AT THE PCPN AS IT MOVES OUT OF WRN UPPER MI. THIS DIMINISHING TREND WILL ALSO BE DUE TO THE FORCING FOCUSING FARTHER S OVER CNTRL WI...ASSOCIATED WITH THE RIGHT REAR OF THE UPPER JET AND H850-700 WAA. THIS REFOCUSING HAS BEEN SEEN ON RADAR OVER THE LAST HOUR...WITH SHOWERS BECOMING MORE WIDESPREAD OVER CNTRL/SRN WI. THE QUESTION WITH THE SRN AREA OF PCPN WILL BE HOW FAR N IT WILL TRACK. MODELS CONSISTENT ON THE H925-850 WAA REMAINING OVER THE SE HALF OF WI AND THE ONLY THING REALLY GOING FOR SOME PCPN FARTHER TO THE N IS SOME H850-700 FGEN OVER THE SCNTRL. LOOKING AT FGEN CROSS-SECTIONS OVER THE CWA...THAT AREA IS UNDER THE ASCENDING BRANCH OF FGEN. OTHERWISE...IT SEEMS LIKE MUCH OF REST OF THE AREA WILL BE ON THE DESCENDING BRANCH OF THE FGEN. THIS SUPPORTS A DIMINISHING TREND THE MODELS SHOW WITH THE NRN PCPN AREA AND THINK THAT LLVL DRY ERLY FLOW WILL COMBINE TO LIMIT THE PCPN FROM GOING TOO FAR EAST OF A LINE FROM KMQT/KESC. THUS...HAVE DIMINISHED POPS OVER THE E TO JUST SLIGHTS. FOR THE STRONGER PCPN AREA...00Z MODEL RUNS...ALONG WITH THE HOURLY RUC RUNS...ALL SHOW THIS STRONGER PCPN JUST BRUSHING THE SCNTRL CWA AND CORRELATES WELL WITH THE FGEN. AS FOR PCPN AMNTS...THE DIMINISHING TREND OVER THE N SHOULD KEEP LIQUID AMNTS LIGHT. ALONG THE WI BORDER...COULD SEE AMNTS IN THE 0.1 TO 0.2 RANGE...WITH THE HIGHEST AMNTS NEAR THE CITY OF MENOMINEE. 29/21Z SREF SUPPORTS THAT SOLN AND SHOWING BEST CHANCES OF 0.1IN ALONG THE WI BORDER AND MAINLY NEAR MENOMINEE...SO FEEL THAT IS THE WAY TO GO. RUC/NAM SOUNDINGS SHOW THE PCPN FALLING AS SNOW FOR THE FIRST HOUR OR TWO OF PCPN...BUT THEN START TRANSITIONING TO A -RA/DZ THROUGH THE MORNING HOURS FROM W TO E. THIS IS DUE TO DRIER AIR ALOFT MOVING INTO THE AREA FROM W TO E AFTER 12Z. OVER THE FAR WEST...WARMER H875 TEMPS WILL PRODUCE A QUICKER CHANGE OVER TO RAIN OVER GOGEBIC COUNTY...PROBABLY TOWARDS DAYBREAK. FORTUNATELY...LLVL TEMPERATURES SHOULD BE WARMING AT THAT TIME AND LIMIT POTENTIAL FOR FREEZING ON THE SFC. PREVIOUS SHIFT HAD A GOOD HANDLE ON THIS AND WILL FOLLOW THAT TRANSITION. THUS...SNOW AMNTS SHOULDN/T BE ANYTHING TOO SUBSTANTIAL. HAVE AROUND AN INCH FOR THE WI BORDER AREA AND TAPER IT OFF TO A DUSTING OVER THE N. IF STRONGER PCPN MAKES IT TO MENOMINEE...COULD SEE A HEAVIER BURST OF SNOW TOWARDS THE MORNING COMMUTE THAT COULD QUICKLY PRODUCE AN INCH OR TWO OF SNOW. WITH THIS BEING THE FIRST MEASUREABLE SNOW FOR A WHILE AND IT OCCURRING DURING THE MORNING COMMUTE...WITH CONTINUE THE SPS FOR THE SCNTRL THROUGH THE MORNING HOURS. FOR THE REST OF THE DAY...EXPECT THE PCPN TO QUICKLY TRANSITION TO THE SE WITH THE BETTER LLVL WAA AND END UP PRODUCING A CLOUDY DAY. HAVE LINGERING SOME LOW POPS FOR SOME LIGHT RAIN SHOWERS AND DRIZZLE THROUGH THE EARLY AFTN...BUT THEN EXPECT THAT TO COME TO AN END. TONIGHT...SFC HIGH PRESSURE RIDGE MOVES BACK INTO THE AREA...BUT LLVL MOISTURE BELOW H900 REMAINS. THINK THE LOW CLOUDS WILL PERSIST AND BE THE THICKEST OVER THE CNTRL CWA...WHERE THE LLVL MOISTURE REMAINS IN PLACE AND H925 TEMPS OF -3C OVER LK MI WILL HELP WITH SOME LK INSTABILITY. IN ADDITION...LIGHT SE UPSLOPE FLOW WILL HELP KEEP THE CLOUDS IN PLACE. FARTHER E...DRY ERLY FLOW FROM THE SFC RIDGE WILL KEEP SKIES MORE PARTLY CLOUDY TOWARDS LUCE COUNTY. OVER THE FAR W...COULD BE SOME DOWNSLOPE BREAKS IN THE CLOUDS OVER WRN GOGEBIC/ONTONAGON COUNTIES. WITH THIS LLVL MOISTURE AND UPSLOPE FLOW...COULD BE SOME -DZ OR LOW CLOUD FOG FROM KMQT/KSAW TO KIMT BUT OVERALL POTENTIAL SEEMS LIMITED TO MENTION AT THIS POINT. SATURDAY...SFC HIGH SLIDES E AS STRONG UPPER JET ROUNDING THE AMPLIFYING UPPER RIDGE MOVES INTO SRN MANITOBA/ONTARIO. SHORTWAVE ASSOCIATED WITH THIS JET WILL DEVELOP A SFC LOW IN THE SAME AREA ON SAT. EXPECT LLVL MOISTURE TO BE LINGERING INTO THE MORNING. DIURNAL MIXING AND WINDS BACKING TO THE S SHOULD ALLOW FOR THE LOW CLOUDS TO BREAK UP TOWARDS MID DAY...WITH THEM HANGING ON THE LONGEST OVER THE UPSLOPE CNTRL CWA. AS THE LOW CLOUDS DIMINISH...MID CLOUDS WILL BEGIN MOVING IN AHEAD OF THE SHORTWAVE AND UNDER THE INCREASING WAA...ESPECIALLY OVER THE NW HALF OF THE CWA. MOISTURE IS MARGINAL...AND BEST FORCING FROM THE SHORTWAVE IS IN CANADA...SO DON/T THINK THE CHANCES OF PCPN DEVELOPING IS TOO HIGH BUT WILL CONTINUE TO MENTION SLIGHTS. DID BRING THE POPS A LITTLE FARTHER S TO COVER THE KEWEENAW PENINSULA. LOWERED TD VALUES SOME OVER THE FAR ERN CWA...WHERE THERE WILL BE GREATER MIXING WITH LESS CLOUDS AND DRIER AIR CLOSER TO THE SFC RIDGE. DIDN/T GO AS LOW AS NAM/ECMWF ML DEWPOINT VALUES...IN THE MID TEENS...BUT LOWERED INTO THE LOWER 20S. WARMEST HIGHS WILL BE OUT WEST...WHERE THE SRLY FLOW WILL PULL H875 TOWARDS 10C. WON/T MIX QUITE THAT HIGH...BUT SHOULD MIX BETWEEN THERE AND H900...WHICH WOULD PRODUCE HIGHS IN THE UPPER 50S TO NEAR 60. IF IT COULD MIX SLIGHTLY HIGHER...WOULD EASILY HAVE TEMPS IN THE MID 60S. FARTHER E...THE LINGERING LOW CLOUDS IN THE MORNING WILL LIMIT THE WARM UP...ALONG WITH COOLER H900 TEMPS LINGERING UNDER THE INITIAL ESE FLOW. TEMPS OVER THE CNTRL/EAST WILL DEPEND ON HOW QUICKLY THE WARMER AIR ALOFT ARRIVES IN THE AFTN...BUT THE BREAKS TOWARDS MID DAY WILL PRODUCE HIGHS IN THE MID 40S TO LOWER 50S. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 423 AM EDT FRI MAR 30 2012 GFS SHOWS A RIDGE BUILDING INTO THE AREA ON SUNDAY WITH A SHORTWAVE PASSING BY TO THE NORTH SAT NIGHT. A WARM FRONT COMES THROUGH ON SUNDAY NIGHT WITH TROUGHING MOVING IN FOR MONDAY. THIS WILL CONTINUE TO BE QUITE ACTIVE THIS PERIOD WITH PCPN CHANCES OVER THE NORTH AND EAST SAT NIGHT AND THEN OVER THE AREA FOR SUNDAY NIGHT AND MONDAY. WENT WITH CHANCE POPS FOR THESE TIME PERIODS. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER. IN THE EXTENDED...ABOVE NORMAL TEMPERATURES CONTINUE...BUT CONFIDENCE IS FAIRLY LOW AS POSITION OF FRONTS COULD BE TRICKY FOR HIGH TEMPERATURES. IF THE WARM FRONT AND WARM SECTOR PART OF THE STORM MAKES IT THROUGH THE AREA...COULD BE VERY WARM. RIGHT NOW...GFS AND ECMWF TAKE SFC LOW PRESSURE TO THE SOUTH AND KEEP THE AREA MORE TOWARDS THE COLDER PART OF THE STORM. CHANCE POPS CONTINUE MONDAY INTO TUESDAY BEFORE DRY WEATHER MOVES IN FOR TUE NIGHT AND LASTS INTO THURSDAY AS TROUGHING CONTINUES TO THE EAST OF THE AREA WITH UPPER LEVEL RIDGING TO THE WEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 130 PM EDT FRI MAR 30 2012 LOW LEVEL MOISTURE STREAMING OVER THE AREA THIS AFTERNOON SHOULD LEAD TO SOME SHOWERS AT SAW AND BR AT IWD. WITH THE SE FLOW...CMX IS NOT EXPERIENCING AS LOW OF CIGS/VIS DUE TO DOWNSLOPING WINDS OFF THE HURON MOUNTAINS. TONIGHT...LOW LEVEL MOISTURE WILL LIKELY REMAIN TONIGHT AND LEAD TO LOWERING MVFR CIGS AT ALL THREE SITES. KSAW WILL HAVE THE BEST CHANCE OF SEEING IFR CIGS WITH UPSLOPE SERLY FLOW. KCMX WILL NOT SEE AS LOW OF CIGS DUE TO CONTINUED DOWNSLOPING FLOW OFF THE HURON MOUNTAINS. KIWD WILL SEE SOME DOWNSLOPING WITH THAT WIND DIRECTION SO HAVE CIGS HIGHER THAN SAW BUT STILL IN THE MVFR CATEGORY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 423 AM EDT FRI MAR 30 2012 LAKE SUPERIOR WILL BE BETWEEN HIGH PRESSURE IN ONTARIO AND A LOW PRESSURE SYSTEM MOVING THROUGH NRN ILLINOIS. THIS WILL PRODUCE SE WINDS UP TO 25KTS TODAY...BEFORE DIMINISHING THIS AFTN/EVENING...AS A HIGH PRESSURE RIDGE REESTABLISHES ITSELF OVER LAKE SUPERIOR. THIS SHOULD KEEP WINDS BELOW 25KTS THROUGH THE WEEKEND AS ANOTHER LOW MOVES THROUGH MANITOBA/ONTARIO ON SATURDAY. LOW PRESSURE DEVELOPING OVER THE NORTHERN/CENTRAL PLAINS ON SUNDAY WILL APPROACH THE GREAT LAKES FOR THE BEGINNING OF NEXT WEEK. THIS LOW WILL WEAKEN AS IT MOVES ACROSS THE GREAT LAKES ON MONDAY AND TUESDAY AND WINDS SHOULD STAY BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...07 AVIATION...TITUS MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
706 AM EDT FRI MAR 30 2012 .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 423 AM EDT FRI MAR 30 2012 BROAD AREA OF SHOWERS STRETCHING FROM THE ARROWHEAD OF MN THROUGH WRN UPPER MI...WRN TWO THIRDS OF WI AND INTO ERN IOWA AT 07Z. OVER THE ARROWHEAD OF MN AND INTO WRN UPPER MI...SHOWERS HAVE BEEN MAINLY IN THE FORM OF SNOW. RECENT WEBCAM IMAGES IN IRONWOOD SHOW A DUSTING OF SNOW ON THE GROUND OVER THE LAST HOUR OR SO. FARTHER SOUTH AND WEST...STARTING TO SEE A TRANSITION TO RAIN AS THE NOSE OF WARM AIR AND DRY AIR ALOFT ARE STARTING TO TURN THE PCPN BACK TO RAIN OVER NW WI. THIS IS ALL RAIN THROUGH THE REST OF WI AND INTO IOWA...WHERE CONVECTION DEVELOPED DURING THE EVENING AND HAS SPREAD NE. THE PCPN IS ASSOCIATED WITH A SHORTWAVE MOVING THROUGH THE CNTRL/NRN PLAINS STATES...WHILE A SFC LOW IS TRACKING THROUGH NRN MO AND SRN IOWA. PCPN FOR THIS MORNING IS THE MAIN FEATURE OF CONCERN FOR THE SHORT TERM FORECAST. THE NRN PART OF THE PCPN AREA IS THE INITIAL AREA OF CONCERN. THIS SHOULD CONTINUE TO THE E OVER THE NEXT SEVERAL HOURS...BUT WITH THE MID-LOW LVL DRY AIR IN PLACE...EXPECT THIS TO EAT AWAY AT THE PCPN AS IT MOVES OUT OF WRN UPPER MI. THIS DIMINISHING TREND WILL ALSO BE DUE TO THE FORCING FOCUSING FARTHER S OVER CNTRL WI...ASSOCIATED WITH THE RIGHT REAR OF THE UPPER JET AND H850-700 WAA. THIS REFOCUSING HAS BEEN SEEN ON RADAR OVER THE LAST HOUR...WITH SHOWERS BECOMING MORE WIDESPREAD OVER CNTRL/SRN WI. THE QUESTION WITH THE SRN AREA OF PCPN WILL BE HOW FAR N IT WILL TRACK. MODELS CONSISTENT ON THE H925-850 WAA REMAINING OVER THE SE HALF OF WI AND THE ONLY THING REALLY GOING FOR SOME PCPN FARTHER TO THE N IS SOME H850-700 FGEN OVER THE SCNTRL. LOOKING AT FGEN CROSS-SECTIONS OVER THE CWA...THAT AREA IS UNDER THE ASCENDING BRANCH OF FGEN. OTHERWISE...IT SEEMS LIKE MUCH OF REST OF THE AREA WILL BE ON THE DESCENDING BRANCH OF THE FGEN. THIS SUPPORTS A DIMINISHING TREND THE MODELS SHOW WITH THE NRN PCPN AREA AND THINK THAT LLVL DRY ERLY FLOW WILL COMBINE TO LIMIT THE PCPN FROM GOING TOO FAR EAST OF A LINE FROM KMQT/KESC. THUS...HAVE DIMINISHED POPS OVER THE E TO JUST SLIGHTS. FOR THE STRONGER PCPN AREA...00Z MODEL RUNS...ALONG WITH THE HOURLY RUC RUNS...ALL SHOW THIS STRONGER PCPN JUST BRUSHING THE SCNTRL CWA AND CORRELATES WELL WITH THE FGEN. AS FOR PCPN AMNTS...THE DIMINISHING TREND OVER THE N SHOULD KEEP LIQUID AMNTS LIGHT. ALONG THE WI BORDER...COULD SEE AMNTS IN THE 0.1 TO 0.2 RANGE...WITH THE HIGHEST AMNTS NEAR THE CITY OF MENOMINEE. 29/21Z SREF SUPPORTS THAT SOLN AND SHOWING BEST CHANCES OF 0.1IN ALONG THE WI BORDER AND MAINLY NEAR MENOMINEE...SO FEEL THAT IS THE WAY TO GO. RUC/NAM SOUNDINGS SHOW THE PCPN FALLING AS SNOW FOR THE FIRST HOUR OR TWO OF PCPN...BUT THEN START TRANSITIONING TO A -RA/DZ THROUGH THE MORNING HOURS FROM W TO E. THIS IS DUE TO DRIER AIR ALOFT MOVING INTO THE AREA FROM W TO E AFTER 12Z. OVER THE FAR WEST...WARMER H875 TEMPS WILL PRODUCE A QUICKER CHANGE OVER TO RAIN OVER GOGEBIC COUNTY...PROBABLY TOWARDS DAYBREAK. FORTUNATELY...LLVL TEMPERATURES SHOULD BE WARMING AT THAT TIME AND LIMIT POTENTIAL FOR FREEZING ON THE SFC. PREVIOUS SHIFT HAD A GOOD HANDLE ON THIS AND WILL FOLLOW THAT TRANSITION. THUS...SNOW AMNTS SHOULDN/T BE ANYTHING TOO SUBSTANTIAL. HAVE AROUND AN INCH FOR THE WI BORDER AREA AND TAPER IT OFF TO A DUSTING OVER THE N. IF STRONGER PCPN MAKES IT TO MENOMINEE...COULD SEE A HEAVIER BURST OF SNOW TOWARDS THE MORNING COMMUTE THAT COULD QUICKLY PRODUCE AN INCH OR TWO OF SNOW. WITH THIS BEING THE FIRST MEASUREABLE SNOW FOR A WHILE AND IT OCCURRING DURING THE MORNING COMMUTE...WITH CONTINUE THE SPS FOR THE SCNTRL THROUGH THE MORNING HOURS. FOR THE REST OF THE DAY...EXPECT THE PCPN TO QUICKLY TRANSITION TO THE SE WITH THE BETTER LLVL WAA AND END UP PRODUCING A CLOUDY DAY. HAVE LINGERING SOME LOW POPS FOR SOME LIGHT RAIN SHOWERS AND DRIZZLE THROUGH THE EARLY AFTN...BUT THEN EXPECT THAT TO COME TO AN END. TONIGHT...SFC HIGH PRESSURE RIDGE MOVES BACK INTO THE AREA...BUT LLVL MOISTURE BELOW H900 REMAINS. THINK THE LOW CLOUDS WILL PERSIST AND BE THE THICKEST OVER THE CNTRL CWA...WHERE THE LLVL MOISTURE REMAINS IN PLACE AND H925 TEMPS OF -3C OVER LK MI WILL HELP WITH SOME LK INSTABILITY. IN ADDITION...LIGHT SE UPSLOPE FLOW WILL HELP KEEP THE CLOUDS IN PLACE. FARTHER E...DRY ERLY FLOW FROM THE SFC RIDGE WILL KEEP SKIES MORE PARTLY CLOUDY TOWARDS LUCE COUNTY. OVER THE FAR W...COULD BE SOME DOWNSLOPE BREAKS IN THE CLOUDS OVER WRN GOGEBIC/ONTONAGON COUNTIES. WITH THIS LLVL MOISTURE AND UPSLOPE FLOW...COULD BE SOME -DZ OR LOW CLOUD FOG FROM KMQT/KSAW TO KIMT BUT OVERALL POTENTIAL SEEMS LIMITED TO MENTION AT THIS POINT. SATURDAY...SFC HIGH SLIDES E AS STRONG UPPER JET ROUNDING THE AMPLIFYING UPPER RIDGE MOVES INTO SRN MANITOBA/ONTARIO. SHORTWAVE ASSOCIATED WITH THIS JET WILL DEVELOP A SFC LOW IN THE SAME AREA ON SAT. EXPECT LLVL MOISTURE TO BE LINGERING INTO THE MORNING. DIURNAL MIXING AND WINDS BACKING TO THE S SHOULD ALLOW FOR THE LOW CLOUDS TO BREAK UP TOWARDS MID DAY...WITH THEM HANGING ON THE LONGEST OVER THE UPSLOPE CNTRL CWA. AS THE LOW CLOUDS DIMINISH...MID CLOUDS WILL BEGIN MOVING IN AHEAD OF THE SHORTWAVE AND UNDER THE INCREASING WAA...ESPECIALLY OVER THE NW HALF OF THE CWA. MOISTURE IS MARGINAL...AND BEST FORCING FROM THE SHORTWAVE IS IN CANADA...SO DON/T THINK THE CHANCES OF PCPN DEVELOPING IS TOO HIGH BUT WILL CONTINUE TO MENTION SLIGHTS. DID BRING THE POPS A LITTLE FARTHER S TO COVER THE KEWEENAW PENINSULA. LOWERED TD VALUES SOME OVER THE FAR ERN CWA...WHERE THERE WILL BE GREATER MIXING WITH LESS CLOUDS AND DRIER AIR CLOSER TO THE SFC RIDGE. DIDN/T GO AS LOW AS NAM/ECMWF ML DEWPOINT VALUES...IN THE MID TEENS...BUT LOWERED INTO THE LOWER 20S. WARMEST HIGHS WILL BE OUT WEST...WHERE THE SRLY FLOW WILL PULL H875 TOWARDS 10C. WON/T MIX QUITE THAT HIGH...BUT SHOULD MIX BETWEEN THERE AND H900...WHICH WOULD PRODUCE HIGHS IN THE UPPER 50S TO NEAR 60. IF IT COULD MIX SLIGHTLY HIGHER...WOULD EASILY HAVE TEMPS IN THE MID 60S. FARTHER E...THE LINGERING LOW CLOUDS IN THE MORNING WILL LIMIT THE WARM UP...ALONG WITH COOLER H900 TEMPS LINGERING UNDER THE INITIAL ESE FLOW. TEMPS OVER THE CNTRL/EAST WILL DEPEND ON HOW QUICKLY THE WARMER AIR ALOFT ARRIVES IN THE AFTN...BUT THE BREAKS TOWARDS MID DAY WILL PRODUCE HIGHS IN THE MID 40S TO LOWER 50S. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 423 AM EDT FRI MAR 30 2012 GFS SHOWS A RIDGE BUILDING INTO THE AREA ON SUNDAY WITH A SHORTWAVE PASSING BY TO THE NORTH SAT NIGHT. A WARM FRONT COMES THROUGH ON SUNDAY NIGHT WITH TROUGHING MOVING IN FOR MONDAY. THIS WILL CONTINUE TO BE QUITE ACTIVE THIS PERIOD WITH PCPN CHANCES OVER THE NORTH AND EAST SAT NIGHT AND THEN OVER THE AREA FOR SUNDAY NIGHT AND MONDAY. WENT WITH CHANCE POPS FOR THESE TIME PERIODS. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER. IN THE EXTENDED...ABOVE NORMAL TEMPERATURES CONTINUE...BUT CONFIDENCE IS FAIRLY LOW AS POSITION OF FRONTS COULD BE TRICKY FOR HIGH TEMPERATURES. IF THE WARM FRONT AND WARM SECTOR PART OF THE STORM MAKES IT THROUGH THE AREA...COULD BE VERY WARM. RIGHT NOW...GFS AND ECMWF TAKE SFC LOW PRESSURE TO THE SOUTH AND KEEP THE AREA MORE TOWARDS THE COLDER PART OF THE STORM. CHANCE POPS CONTINUE MONDAY INTO TUESDAY BEFORE DRY WEATHER MOVES IN FOR TUE NIGHT AND LASTS INTO THURSDAY AS TROUGHING CONTINUES TO THE EAST OF THE AREA WITH UPPER LEVEL RIDGING TO THE WEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 705 AM EDT FRI MAR 30 2012 UPPER LEVEL DISTURBANCE MOVING ACROSS WISCONSIN AND SOUTHERN UPPER MICHIGAN WILL BRUSH KCMX/KSAW WITH -SN AT THE START OF THE TAF PERIOD. SHOULD SEE VSBYS IMPROVING QUICKLY THIS MORNING AS THE SNOW CONTINUES IT/S DIMINISHING TREND. HAVE LINGERED IFR CIGS AT KCMX THROUGH THE MORNING HOURS DUE TO FAVORABLE UPSLOPE FLOW AND MOISTENING FROM THE SNOW. OTHERWISE...EXPECT MVFR CIGS AT THE REST OF THE SITES THROUGH THE AFTN. TONIGHT...LOW LEVEL MOISTURE WILL LIKELY REMAIN TONIGHT AND LEAD TO LOWERING MVFR CIGS AT ALL THREE SITES. KSAW WILL HAVE THE BEST CHANCE OF SEEING IFR CIGS WITH UPSLOPE SERLY FLOW. KCMX ALSO WILL HAVE FAVORABLE FLOW...BUT KIWD WILL SEE SOME DOWNSLOPING WITH THAT WIND DIRECTION SO HAVE CIGS A LITTLE HIGHER IN MVFR CAT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 423 AM EDT FRI MAR 30 2012 LAKE SUPERIOR WILL BE BETWEEN HIGH PRESSURE IN ONTARIO AND A LOW PRESSURE SYSTEM MOVING THROUGH NRN ILLINOIS. THIS WILL PRODUCE SE WINDS UP TO 25KTS TODAY...BEFORE DIMINISHING THIS AFTN/EVENING...AS A HIGH PRESSURE RIDGE REESTABLISHES ITSELF OVER LAKE SUPERIOR. THIS SHOULD KEEP WINDS BELOW 25KTS THROUGH THE WEEKEND AS ANOTHER LOW MOVES THROUGH MANITOBA/ONTARIO ON SATURDAY. LOW PRESSURE DEVELOPING OVER THE NORTHERN/CENTRAL PLAINS ON SUNDAY WILL APPROACH THE GREAT LAKES FOR THE BEGINNING OF NEXT WEEK. THIS LOW WILL WEAKEN AS IT MOVES ACROSS THE GREAT LAKES ON MONDAY AND TUESDAY AND WINDS SHOULD STAY BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...07 AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 AM EDT FRI MAR 30 2012 .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 423 AM EDT FRI MAR 30 2012 BROAD AREA OF SHOWERS STRETCHING FROM THE ARROWHEAD OF MN THROUGH WRN UPPER MI...WRN TWO THIRDS OF WI AND INTO ERN IOWA AT 07Z. OVER THE ARROWHEAD OF MN AND INTO WRN UPPER MI...SHOWERS HAVE BEEN MAINLY IN THE FORM OF SNOW. RECENT WEBCAM IMAGES IN IRONWOOD SHOW A DUSTING OF SNOW ON THE GROUND OVER THE LAST HOUR OR SO. FARTHER SOUTH AND WEST...STARTING TO SEE A TRANSITION TO RAIN AS THE NOSE OF WARM AIR AND DRY AIR ALOFT ARE STARTING TO TURN THE PCPN BACK TO RAIN OVER NW WI. THIS IS ALL RAIN THROUGH THE REST OF WI AND INTO IOWA...WHERE CONVECTION DEVELOPED DURING THE EVENING AND HAS SPREAD NE. THE PCPN IS ASSOCIATED WITH A SHORTWAVE MOVING THROUGH THE CNTRL/NRN PLAINS STATES...WHILE A SFC LOW IS TRACKING THROUGH NRN MO AND SRN IOWA. PCPN FOR THIS MORNING IS THE MAIN FEATURE OF CONCERN FOR THE SHORT TERM FORECAST. THE NRN PART OF THE PCPN AREA IS THE INITIAL AREA OF CONCERN. THIS SHOULD CONTINUE TO THE E OVER THE NEXT SEVERAL HOURS...BUT WITH THE MID-LOW LVL DRY AIR IN PLACE...EXPECT THIS TO EAT AWAY AT THE PCPN AS IT MOVES OUT OF WRN UPPER MI. THIS DIMINISHING TREND WILL ALSO BE DUE TO THE FORCING FOCUSING FARTHER S OVER CNTRL WI...ASSOCIATED WITH THE RIGHT REAR OF THE UPPER JET AND H850-700 WAA. THIS REFOCUSING HAS BEEN SEEN ON RADAR OVER THE LAST HOUR...WITH SHOWERS BECOMING MORE WIDESPREAD OVER CNTRL/SRN WI. THE QUESTION WITH THE SRN AREA OF PCPN WILL BE HOW FAR N IT WILL TRACK. MODELS CONSISTENT ON THE H925-850 WAA REMAINING OVER THE SE HALF OF WI AND THE ONLY THING REALLY GOING FOR SOME PCPN FARTHER TO THE N IS SOME H850-700 FGEN OVER THE SCNTRL. LOOKING AT FGEN CROSS-SECTIONS OVER THE CWA...THAT AREA IS UNDER THE ASCENDING BRANCH OF FGEN. OTHERWISE...IT SEEMS LIKE MUCH OF REST OF THE AREA WILL BE ON THE DESCENDING BRANCH OF THE FGEN. THIS SUPPORTS A DIMINISHING TREND THE MODELS SHOW WITH THE NRN PCPN AREA AND THINK THAT LLVL DRY ERLY FLOW WILL COMBINE TO LIMIT THE PCPN FROM GOING TOO FAR EAST OF A LINE FROM KMQT/KESC. THUS...HAVE DIMINISHED POPS OVER THE E TO JUST SLIGHTS. FOR THE STRONGER PCPN AREA...00Z MODEL RUNS...ALONG WITH THE HOURLY RUC RUNS...ALL SHOW THIS STRONGER PCPN JUST BRUSHING THE SCNTRL CWA AND CORRELATES WELL WITH THE FGEN. AS FOR PCPN AMNTS...THE DIMINISHING TREND OVER THE N SHOULD KEEP LIQUID AMNTS LIGHT. ALONG THE WI BORDER...COULD SEE AMNTS IN THE 0.1 TO 0.2 RANGE...WITH THE HIGHEST AMNTS NEAR THE CITY OF MENOMINEE. 29/21Z SREF SUPPORTS THAT SOLN AND SHOWING BEST CHANCES OF 0.1IN ALONG THE WI BORDER AND MAINLY NEAR MENOMINEE...SO FEEL THAT IS THE WAY TO GO. RUC/NAM SOUNDINGS SHOW THE PCPN FALLING AS SNOW FOR THE FIRST HOUR OR TWO OF PCPN...BUT THEN START TRANSITIONING TO A -RA/DZ THROUGH THE MORNING HOURS FROM W TO E. THIS IS DUE TO DRIER AIR ALOFT MOVING INTO THE AREA FROM W TO E AFTER 12Z. OVER THE FAR WEST...WARMER H875 TEMPS WILL PRODUCE A QUICKER CHANGE OVER TO RAIN OVER GOGEBIC COUNTY...PROBABLY TOWARDS DAYBREAK. FORTUNATELY...LLVL TEMPERATURES SHOULD BE WARMING AT THAT TIME AND LIMIT POTENTIAL FOR FREEZING ON THE SFC. PREVIOUS SHIFT HAD A GOOD HANDLE ON THIS AND WILL FOLLOW THAT TRANSITION. THUS...SNOW AMNTS SHOULDN/T BE ANYTHING TOO SUBSTANTIAL. HAVE AROUND AN INCH FOR THE WI BORDER AREA AND TAPER IT OFF TO A DUSTING OVER THE N. IF STRONGER PCPN MAKES IT TO MENOMINEE...COULD SEE A HEAVIER BURST OF SNOW TOWARDS THE MORNING COMMUTE THAT COULD QUICKLY PRODUCE AN INCH OR TWO OF SNOW. WITH THIS BEING THE FIRST MEASUREABLE SNOW FOR A WHILE AND IT OCCURRING DURING THE MORNING COMMUTE...WITH CONTINUE THE SPS FOR THE SCNTRL THROUGH THE MORNING HOURS. FOR THE REST OF THE DAY...EXPECT THE PCPN TO QUICKLY TRANSITION TO THE SE WITH THE BETTER LLVL WAA AND END UP PRODUCING A CLOUDY DAY. HAVE LINGERING SOME LOW POPS FOR SOME LIGHT RAIN SHOWERS AND DRIZZLE THROUGH THE EARLY AFTN...BUT THEN EXPECT THAT TO COME TO AN END. TONIGHT...SFC HIGH PRESSURE RIDGE MOVES BACK INTO THE AREA...BUT LLVL MOISTURE BELOW H900 REMAINS. THINK THE LOW CLOUDS WILL PERSIST AND BE THE THICKEST OVER THE CNTRL CWA...WHERE THE LLVL MOISTURE REMAINS IN PLACE AND H925 TEMPS OF -3C OVER LK MI WILL HELP WITH SOME LK INSTABILITY. IN ADDITION...LIGHT SE UPSLOPE FLOW WILL HELP KEEP THE CLOUDS IN PLACE. FARTHER E...DRY ERLY FLOW FROM THE SFC RIDGE WILL KEEP SKIES MORE PARTLY CLOUDY TOWARDS LUCE COUNTY. OVER THE FAR W...COULD BE SOME DOWNSLOPE BREAKS IN THE CLOUDS OVER WRN GOGEBIC/ONTONAGON COUNTIES. WITH THIS LLVL MOISTURE AND UPSLOPE FLOW...COULD BE SOME -DZ OR LOW CLOUD FOG FROM KMQT/KSAW TO KIMT BUT OVERALL POTENTIAL SEEMS LIMITED TO MENTION AT THIS POINT. SATURDAY...SFC HIGH SLIDES E AS STRONG UPPER JET ROUNDING THE AMPLIFYING UPPER RIDGE MOVES INTO SRN MANITOBA/ONTARIO. SHORTWAVE ASSOCIATED WITH THIS JET WILL DEVELOP A SFC LOW IN THE SAME AREA ON SAT. EXPECT LLVL MOISTURE TO BE LINGERING INTO THE MORNING. DIURNAL MIXING AND WINDS BACKING TO THE S SHOULD ALLOW FOR THE LOW CLOUDS TO BREAK UP TOWARDS MID DAY...WITH THEM HANGING ON THE LONGEST OVER THE UPSLOPE CNTRL CWA. AS THE LOW CLOUDS DIMINISH...MID CLOUDS WILL BEGIN MOVING IN AHEAD OF THE SHORTWAVE AND UNDER THE INCREASING WAA...ESPECIALLY OVER THE NW HALF OF THE CWA. MOISTURE IS MARGINAL...AND BEST FORCING FROM THE SHORTWAVE IS IN CANADA...SO DON/T THINK THE CHANCES OF PCPN DEVELOPING IS TOO HIGH BUT WILL CONTINUE TO MENTION SLIGHTS. DID BRING THE POPS A LITTLE FARTHER S TO COVER THE KEWEENAW PENINSULA. LOWERED TD VALUES SOME OVER THE FAR ERN CWA...WHERE THERE WILL BE GREATER MIXING WITH LESS CLOUDS AND DRIER AIR CLOSER TO THE SFC RIDGE. DIDN/T GO AS LOW AS NAM/ECMWF ML DEWPOINT VALUES...IN THE MID TEENS...BUT LOWERED INTO THE LOWER 20S. WARMEST HIGHS WILL BE OUT WEST...WHERE THE SRLY FLOW WILL PULL H875 TOWARDS 10C. WON/T MIX QUITE THAT HIGH...BUT SHOULD MIX BETWEEN THERE AND H900...WHICH WOULD PRODUCE HIGHS IN THE UPPER 50S TO NEAR 60. IF IT COULD MIX SLIGHTLY HIGHER...WOULD EASILY HAVE TEMPS IN THE MID 60S. FARTHER E...THE LINGERING LOW CLOUDS IN THE MORNING WILL LIMIT THE WARM UP...ALONG WITH COOLER H900 TEMPS LINGERING UNDER THE INITIAL ESE FLOW. TEMPS OVER THE CNTRL/EAST WILL DEPEND ON HOW QUICKLY THE WARMER AIR ALOFT ARRIVES IN THE AFTN...BUT THE BREAKS TOWARDS MID DAY WILL PRODUCE HIGHS IN THE MID 40S TO LOWER 50S. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 423 AM EDT FRI MAR 30 2012 GFS SHOWS A RIDGE BUILDING INTO THE AREA ON SUNDAY WITH A SHORTWAVE PASSING BY TO THE NORTH SAT NIGHT. A WARM FRONT COMES THROUGH ON SUNDAY NIGHT WITH TROUGHING MOVING IN FOR MONDAY. THIS WILL CONTINUE TO BE QUITE ACTIVE THIS PERIOD WITH PCPN CHANCES OVER THE NORTH AND EAST SAT NIGHT AND THEN OVER THE AREA FOR SUNDAY NIGHT AND MONDAY. WENT WITH CHANCE POPS FOR THESE TIME PERIODS. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER. IN THE EXTENDED...ABOVE NORMAL TEMPERATURES CONTINUE...BUT CONFIDENCE IS FAIRLY LOW AS POSITION OF FRONTS COULD BE TRICKY FOR HIGH TEMPERATURES. IF THE WARM FRONT AND WARM SECTOR PART OF THE STORM MAKES IT THROUGH THE AREA...COULD BE VERY WARM. RIGHT NOW...GFS AND ECMWF TAKE SFC LOW PRESSURE TO THE SOUTH AND KEEP THE AREA MORE TOWARDS THE COLDER PART OF THE STORM. CHANCE POPS CONTINUE MONDAY INTO TUESDAY BEFORE DRY WEATHER MOVES IN FOR TUE NIGHT AND LASTS INTO THURSDAY AS TROUGHING CONTINUES TO THE EAST OF THE AREA WITH UPPER LEVEL RIDGING TO THE WEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 135 AM EDT FRI MAR 30 2012 A SHORTWAVE MOVING TOWARD THE AREA WILL BRING PCPN INTO UPPER MICHIGAN. HOWEVER...THE GREATER FORCING AND HEAVIER AMOUNTS ARE EXPECTED TO REMAIN SOUTH OF THE TAF SITES. NEVERTHELESS...SOME -SN/RA WILL MOVE INTO IWD OVERNIGHT AND EVENTUALLY TOWARD CMX AND SAW TOWARD 12Z. CIGS SHOULD DROP INTO THE MVFR RANGE AS THE PCPN DEVELOPS. CONTINUED TO USE THE NAM FOR TIMING OF PRECIP AND MOISTURE FOR LOW CLOUDS. CONFIDENCE IN PRECIP CHANCES AND TIMING IS LOWER GIVEN TRENDS TOWARD A MORE SOUTHERN TRACK OF THE PCPN AREA. HOWEVER...EXPECT THAT WITH UPSLOPE ESE FLOW INTO CMX/SAW MVFR CONDITIONS ARE STILL ON TRACK. BY LATER IN THE DAY...SOME IMRPROVEMENT IS EXPECTED WITH VFR CONDITIONS AT IWD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 423 AM EDT FRI MAR 30 2012 LAKE SUPERIOR WILL BE BETWEEN HIGH PRESSURE IN ONTARIO AND A LOW PRESSURE SYSTEM MOVING THROUGH NRN ILLINOIS. THIS WILL PRODUCE SE WINDS UP TO 25KTS TODAY...BEFORE DIMINISHING THIS AFTN/EVENING...AS A HIGH PRESSURE RIDGE REESTABLISHES ITSELF OVER LAKE SUPERIOR. THIS SHOULD KEEP WINDS BELOW 25KTS THROUGH THE WEEKEND AS ANOTHER LOW MOVES THROUGH MANITOBA/ONTARIO ON SATURDAY. LOW PRESSURE DEVELOPING OVER THE NORTHERN/CENTRAL PLAINS ON SUNDAY WILL APPROACH THE GREAT LAKES FOR THE BEGINNING OF NEXT WEEK. THIS LOW WILL WEAKEN AS IT MOVES ACROSS THE GREAT LAKES ON MONDAY AND TUESDAY AND WINDS SHOULD STAY BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...07 AVIATION...JLB MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
733 AM CDT FRI MAR 30 2012 .UPDATE... 12Z AVIATION DISCUSSION ADDED BELOW. && .DISCUSSION... THE RAIN WITH YESTERDAYS SYSTEM SHOULD BE OUT OF OUR EASTERN AREAS BY THIS MORNING ALTHOUGH THE RADAR LOOP SHOWS A BIT OF A TWIST ON THE BACK EDGE. IN FACT..THE OVERALL PATTERN OVER THE CONUS AND INTO CANADA SHOWS MULTIPLE SMALL WAVES. ONE OF THESE IS CROSSING INTO SOUTH DAKOTA AT THIS TIME AND LOOKS TO PASS MAINLY OVER IOWA BUT BRUSHING FAR SOUTHERN MINNESOTA. A FEW RETURNS SHOWING UP BUT RAIN NOT LIKELY AS MOST OF THE DEEPER MOISTURE SWEPT OUT FROM THE SYSTEM OFF TO THE EAST. AREAS OF STRATUS AND FOG HAS FORMED OVER WESTERN MINNESOTA IN THE LINGERING HIGHER DEW POINTS. THERE ARE INDICATIONS THAT THE LOW CLOUDS WILL HANG IN OVER WISCONSIN AND EASTERN MINNESOTA IN THE EASTERLY FLOW WHICH WILL OF COURSE BE PROBLEMATIC FOR HIGH TEMPS..ESPECIALLY TODAY AND SATURDAY...BUT EVEN INTO SUNDAY WITH THE WARM FRONT INTENSIFYING. WILL HAVE TO WATCH THE DEVELOPING WARM ADVECTION PATTERN FOR SATURDAY AS THERE IS A HINT OF WEAK WAVE IN THE NORTHWEST FLOW BEFORE MORE UPPER RIDGING DEVELOPS FOR SUNDAY. HAVE ADDED A SLIGHT CHANCE OVER WESTERN WI SATURDAY...BUT WOULD NOT BE SURPRISED TO SEE A NEED FOR PARTS OF EASTERN MN. IT LOOK LIKE MORE OF A HIGH BASED ACCAS SITUATION BUT COULD SEE ISOLATED SHOWERS. FOR SUNDAY HAVE NOT CHANGED MAX TEMPS EXCEPT FOR A FEW DEGREES HIGHER IN SOUTHWEST MN BEHIND THE WARM FRONT. DO NOT SEE MUCH CHANCE OF PRECIP UNTIL LATER SUNDAY NIGHT WITH THE THICKNESS RIDGE GENERALLY OVER THE AREA. IT LOOKS LIKE A SPLIT UPPER FLOW DEVELOPING OVER THE CENTRAL CONUS BUT A RIGHT ENTRANCE REGION OF THE NORTHERN BRANCH OF THE UPPER JET OVER NORTHWEST MN SHOULD AID IN SHOWER THUNDERSTORM DEVELOPMENT. THIS COULD BE SOMEWHAT POST FRONTAL ON MONDAY. IT LOOKS LIKE A DRY PERIOD FOR THE REST OF NEXT WEEK WITH UPPER RIDGING OVER THE NORTHERN AND CENTRAL PLAINS. && .AVIATION.../12Z TAF ISSUANCE/ RAIN HAS MOVED EAST OF THE TERMINALS THIS MORNING...BUT AN EVER LOWERING STRATUS DECK...WITH DENSE FOG ACROSS WRN MN HAS REPLACED IT. NOT EXPECTING ANY IMPROVEMENTS IN CURRENT CONDITIONS UNTIL AT LEAST 15/16Z...WITH BACK EDGE OF STRATUS SLOWLY WORKING EAST TODAY. LATEST RUC RUN HAS THE BACK EDGE OF CLOUDS ALONG I-35 AT 21Z. WI TERMINALS WILL LIKELY NEVER LOSE CIGS TODAY...THOUGH THEY SHOULD WORK THEIR WAY BACK UP TO LOW VFR LEVELS DURING THE AFTERNOON. FOR TONIGHT...CURRENT THINKING BASED OFF OF SREF PROB FOR CIGS LESS THAN 3K FT AND BUFKIT SOUNDINGS FROM BOTH THE NAM/GFS IS THAT LOW STRATUS WILL RETURN. WITH GENERALLY LOW LEVEL RIDGING WORKING ACROSS THE REGION TODAY...WE WILL LIKELY NOT SEE THE MOISTURE SCOURED OUT...SO FAVORED THE STRATUS RETURNING TONIGHT /WITH THE LOWEST CIGS EXPECTED OVER WI/. PRESSURE GRADIENT WILL REMAIN BAGGY THIS PERIOD...WITH LIGHT E-SE WINDS BEING MAINTAINED. KMSP...WITH IFR CIGS OVER WI...IS THE THREAT THROUGH 14Z THAT EAST WINDS MAY BRING SOME OF THESE CIGS INTO THE FIELD...BUT MVFR CONDITIONS WILL BE MOST PREVALENT. DO NOT EXPECT CIGS TO LIFT ABOVE 017 UNTIL BETWEEN 16Z AND 18Z. SHOULD SEE SKIES MOSTLY CLEAR OUT AROUND 00Z...BUT WILL HAVE TO WATCH LOW STRATUS RETURNING LATE TONIGHT. WAS ON THE FENCE ABOUT BRINGING IT BACK...BUT WITH SUB 3K FT CIG PROBS OFF THE SREF UP AROUND 80 PERCENT...DECIDED TO BRING THEM BACK AS CLEARING WILL LIKELY NOT MAKE IT TOO FAR INTO WI. BASED ON NAM/GFS SOUNDINGS...IF THESE CIGS COME IN...THEY COULD DO SO AS IFR. //OUTLOOK...SATURDAY THROUGH WEDNESDAY// SAT-SUN...VFR. SUN NGT-MON...SHRA/TSRA POSSIBLE WITH FROPA. MON NGT-WED...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/MPG
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1230 PM CDT FRI MAR 30 2012 .UPDATE... ISSUED AT 910 AM CDT FRI MAR 30 2012 HAVE UPDATED FORECAST THIS MORNING TO BOOST TEMPERATURES A FEW DEGREES ACROSS THE SOUTHERN PORTION OF THE CWA...AHEAD OF THE FRONT. 850MB TEMPERATURES WOULD SUGGEST HIGHS IN THE LOWER 80S. STRIPPED POPS FROM THE FORECAST FOR THIS MORNING AND CONCENTRATED SCATTERED POPS ALONG AND SOUTH OF I-44 IN MISSOURI AND I-70 IN ILLINOIS FOR THE AFTERNOON HOURS. LATEST HRRR SUGGESTS CONVECTIVE INITIATION WILL OCCUR BETWEEN 18 AND 20Z ALONG THE FRONT. CVKING && .SHORT TERM... ISSUED AT 325 AM CDT FRI MAR 30 2012 (TODAY) SURFACE LOW TO CONTINUE TRACKING TO THE EAST THIS MORNING ACROSS NORTHERN MISSOURI...THEN INTO WESTERN OHIO BY EARLY THIS EVENING. ASSOCIATED COLD FRONT TO SLIDE THROUGH FORECAST AREA TODAY...MOVING INTO NORTHEAST MO...WEST CENTRAL IL JUST AFTER DAYBREAK...THEN INTO THE ST. LOUIS METRO AREA BY MIDDAY. AS FOR CHANCES OF SHOWERS AND THUNDERSTORMS WITH THIS BOUNDARY...DESPITE CAPES BETWEEN 500 AND 2000 J/KG...CONVERGENCE ALONG BOUNDARY CONTINUES TO LOOK WEAK WITH BEST LIFT FURTHER TO THE EAST ALONG THE FRONT...CLOSER TO THE SURFACE LOW. SO BACKED OFF ON POPS A BIT...WITH BEST CHANCES ALONG AND EAST OF MISSISSIPPI RIVER TODAY. COULD SEE SOME STRONG STORMS BY THIS AFTERNOON...MAINLY OVER SOUTHERN IL. AS FOR CLOUDS...SEEING PLENTY OF RESIDUAL MID AND HIGH CLOUDS FROM ACTIVITY THAT FIRED UP OVERNIGHT...BUT THIS SHOULD THIN A BIT ALLOWING FOR A MIX OF SUN AND CLOUDS TODAY. SO TEMPS TO WARM UP INTO THE LOW 70S FAR NORTH TO THE UPPER 70S ALONG AND SOUTH OF I-70. WINDS TO PICKUP FROM THE SOUTH TO SOUTHWEST THIS MORNING AHEAD OF FRONT...THEN SWITCH TO THE NORTHWEST WITH THE PASSAGE OF THE COLD FRONT. BYRD && .LONG TERM... ISSUED AT 320 AM CDT FRI MAR 30 2012 (TONIGHT THROUGH THURSDAY) CDFNT IS EXPECTED TO STALL OVER SRN MO AND FAR SRN IL TONIGHT. A FEW STRAGGLER SHRA/TSRA MAY EXIST INVOF FRONT EARLY THIS EVENING FOR SECTIONS OF SERN MO AND SRN IL BUT SHOULD EXIT OR DISSIPATE BY 9PM. UPPER LEVEL DISTURBANCES...IN THE MEANTIME...WILL CONTINUE TO RIPPLE THRU THE AREA LATER TONIGHT AND SATURDAY BUT ARE REALLY ONLY EXPECTED TO HAVE MUCH IF ANY IMPACT NEAR THE FRONTAL ZONE IN THE FAR SRN FA LATE TONIGHT AND EXPANDING A BIT NWD BY SATURDAY AFTERNOON AS FRONT BEGINS TO BUCKLE NWD AS A WRMFNT. FOR POPS TONIGHT AND SATURDAY...A LOT OF CLOSE CALLS BUT NOT A GOOD FEEL FOR ANYTHING CONSIDERING FRONTAL BOUNDARY SHOULD BE LARGELY IF NOT ENTIRELY OUT OF THE FA DURING THESE TIMES...SO JUST WENT WITH SLIGHT CHCS. WRMFNT WILL MAKE ITS BIG PUSH THRU THE FA SATURDAY NIGHT. MUCH OF THE BETTER LIFT WITH THE LO LEVEL JET SHOULD BE TO THE N OF THE FA BUT WHAT DOES DEVELOP WILL TRY TO TURN SE TOWARDS THE FA AND HAVE ACCOUNTED FOR WITH SOME LO-END POPS. BIG STORY FOR SUNDAY AND MONDAY WILL BE WHAT SHOULD BE THE WARMEST DAYS OF THIS ABNORMALLY WARM SEASON. SUNDAY WILL FEATURE A MODERATELY STRONG S-SW FLOW WITH ABUNDANT SUNSHINE. MIXING HEIGHTS SHOULD REACH H850 AND H850 TEMPS OF 16-18C STRONGLY POINT TOWARDS MID-UPR 80S FOR MAX TEMPS WITH A REASONABLE CHC OF TOUCHING 90F. FEEL COMFORTABLE GOING 2-3F ABOVE THE HIGHEST MOS ON THIS DAY. MONDAY WILL FEATURE A BIT MORE UNCERTAINTY BUT A STRONG ENOUGH SIGNAL WITH WHAT SHOULD BE A FURTHER DELAY TO THE UPPER LEVEL SYSTEM TO THE W TO ALSO GO NEAR PERSISTENCE. SPEAKING OF THE DELAY TO THE UPPER LEVEL SYSTEM ON MONDAY...MODELS CONTINUE TO SHOVE BACK THE BETTER CHCS FOR RAIN EARLY NEXT WEEK TO THE MIDDLE PART OF THE WEEK...WITH BOTH ECMWF AND GFS CLOSING A LO OFF AND AT THIS POINT SHOW A LARGE DEAL OF UNCERTAINTY ON WHERE TO TRACK IT AND HOW FAST TO DO IT. IT IS WELL WITHIN THE REALM OF POSSIBILITY THAT NO RAIN WILL RESULT FROM THIS IF THE UPPER LO TRACKS TOO FAR S OR IS DELAYED TOO MUCH BUT LEANING TOWARDS THE GFS SOLN SINCE IT WAS THE FIRST TO SHOW THE CUTOFF POTENTIAL AND HAS HAD BETTER RUN-TO-RUN CONSISTENCY. THE GFS SUGGESTS AN EXTENDED PERIOD OF RAIN FROM TUESDAY THRU WEDNESDAY AND HAVE CHC CATEGORY POPS FOR THIS PERIOD. TEMPS APPEAR THEY WILL EDGE CLOSER TO SEASONAL AVERAGES...ESPECIALLY IF RAIN MATERIALIZES...BUT WITH ANOTHER BIG RIDGE READY TO BOUNCE BACK FOR LATE WEEK...TEMPS SHOULD HAVE A FAIRLY EASY TIME STAYING ABOVE AVERAGE. TES && .AVIATION... ISSUED AT 1226 PM CDT FRI MAR 30 2012 WEAK COLD FRONT WILL CONTINUE TO SLIDE SOUTHEAST THIS AFTERNOON ACROSS THE AREA WITH SHOWERS AND STORMS DEVELOPING ACROSS SOUTHEAST MISSOURI AND SOUTHWEST ILLINOIS. TOO CLOSE TO NOT HAVE AT LEAST A VCSH/CB IN THE ST. LOUIS METRO TAFS. OTHERWISE...VFR CONDITIONS EXPECTED UNTIL LATER TONIGHT WHEN LIGHT WINDS AND SUFFICIENT LOW LEVEL MOISTURE SHOULD RESULT IN MVFR FOG. SPECIFICS FOR KSTL... VFR CONDITIONS THIS AFTERNOON WITH JUST A SLIGHT CHANCE OF A SHOWER DEVELOPING OVER THE TERMINAL. COLD FRONT WILL SLIDE SOUTHEAST EARLY ON...WITH WINDS BECOMING NORTHWEST. WINDS BECOME LIGHT TONIGHT AND THIS COULD RESULT IN SOME MVFR FOG. WINDS BECOME EAST ON SATURDAY. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
919 AM CDT FRI MAR 30 2012 .UPDATE... ISSUED AT 910 AM CDT FRI MAR 30 2012 HAVE UPDATED FORECAST THIS MORNING TO BOOST TEMPERATURES A FEW DEGREES ACROSS THE SOUTHERN PORTION OF THE CWA...AHEAD OF THE FRONT. 850MB TEMPERATURES WOULD SUGGEST HIGHS IN THE LOWER 80S. STRIPPED POPS FROM THE FORECAST FOR THIS MORNING AND CONCENTRATED SCATTERED POPS ALONG AND SOUTH OF I-44 IN MISSOURI AND I-70 IN ILLINOIS FOR THE AFTERNOON HOURS. LATEST HRRR SUGGESTS CONVECTIVE INITIATION WILL OCCUR BETWEEN 18 AND 20Z ALONG THE FRONT. CVKING && .SHORT TERM... ISSUED AT 325 AM CDT FRI MAR 30 2012 (TODAY) SURFACE LOW TO CONTINUE TRACKING TO THE EAST THIS MORNING ACROSS NORTHERN MISSOURI...THEN INTO WESTERN OHIO BY EARLY THIS EVENING. ASSOCIATED COLD FRONT TO SLIDE THROUGH FORECAST AREA TODAY...MOVING INTO NORTHEAST MO...WEST CENTRAL IL JUST AFTER DAYBREAK...THEN INTO THE ST. LOUIS METRO AREA BY MIDDAY. AS FOR CHANCES OF SHOWERS AND THUNDERSTORMS WITH THIS BOUNDARY...DESPITE CAPES BETWEEN 500 AND 2000 J/KG...CONVERGENCE ALONG BOUNDARY CONTINUES TO LOOK WEAK WITH BEST LIFT FURTHER TO THE EAST ALONG THE FRONT...CLOSER TO THE SURFACE LOW. SO BACKED OFF ON POPS A BIT...WITH BEST CHANCES ALONG AND EAST OF MISSISSIPPI RIVER TODAY. COULD SEE SOME STRONG STORMS BY THIS AFTERNOON...MAINLY OVER SOUTHERN IL. AS FOR CLOUDS...SEEING PLENTY OF RESIDUAL MID AND HIGH CLOUDS FROM ACTIVITY THAT FIRED UP OVERNIGHT...BUT THIS SHOULD THIN A BIT ALLOWING FOR A MIX OF SUN AND CLOUDS TODAY. SO TEMPS TO WARM UP INTO THE LOW 70S FAR NORTH TO THE UPPER 70S ALONG AND SOUTH OF I-70. WINDS TO PICKUP FROM THE SOUTH TO SOUTHWEST THIS MORNING AHEAD OF FRONT...THEN SWITCH TO THE NORTHWEST WITH THE PASSAGE OF THE COLD FRONT. BYRD && .LONG TERM... ISSUED AT 320 AM CDT FRI MAR 30 2012 (TONIGHT THROUGH THURSDAY) CDFNT IS EXPECTED TO STALL OVER SRN MO AND FAR SRN IL TONIGHT. A FEW STRAGGLER SHRA/TSRA MAY EXIST INVOF FRONT EARLY THIS EVENING FOR SECTIONS OF SERN MO AND SRN IL BUT SHOULD EXIT OR DISSIPATE BY 9PM. UPPER LEVEL DISTURBANCES...IN THE MEANTIME...WILL CONTINUE TO RIPPLE THRU THE AREA LATER TONIGHT AND SATURDAY BUT ARE REALLY ONLY EXPECTED TO HAVE MUCH IF ANY IMPACT NEAR THE FRONTAL ZONE IN THE FAR SRN FA LATE TONIGHT AND EXPANDING A BIT NWD BY SATURDAY AFTERNOON AS FRONT BEGINS TO BUCKLE NWD AS A WRMFNT. FOR POPS TONIGHT AND SATURDAY...A LOT OF CLOSE CALLS BUT NOT A GOOD FEEL FOR ANYTHING CONSIDERING FRONTAL BOUNDARY SHOULD BE LARGELY IF NOT ENTIRELY OUT OF THE FA DURING THESE TIMES...SO JUST WENT WITH SLIGHT CHCS. WRMFNT WILL MAKE ITS BIG PUSH THRU THE FA SATURDAY NIGHT. MUCH OF THE BETTER LIFT WITH THE LO LEVEL JET SHOULD BE TO THE N OF THE FA BUT WHAT DOES DEVELOP WILL TRY TO TURN SE TOWARDS THE FA AND HAVE ACCOUNTED FOR WITH SOME LO-END POPS. BIG STORY FOR SUNDAY AND MONDAY WILL BE WHAT SHOULD BE THE WARMEST DAYS OF THIS ABNORMALLY WARM SEASON. SUNDAY WILL FEATURE A MODERATELY STRONG S-SW FLOW WITH ABUNDANT SUNSHINE. MIXING HEIGHTS SHOULD REACH H850 AND H850 TEMPS OF 16-18C STRONGLY POINT TOWARDS MID-UPR 80S FOR MAX TEMPS WITH A REASONABLE CHC OF TOUCHING 90F. FEEL COMFORTABLE GOING 2-3F ABOVE THE HIGHEST MOS ON THIS DAY. MONDAY WILL FEATURE A BIT MORE UNCERTAINTY BUT A STRONG ENOUGH SIGNAL WITH WHAT SHOULD BE A FURTHER DELAY TO THE UPPER LEVEL SYSTEM TO THE W TO ALSO GO NEAR PERSISTENCE. SPEAKING OF THE DELAY TO THE UPPER LEVEL SYSTEM ON MONDAY...MODELS CONTINUE TO SHOVE BACK THE BETTER CHCS FOR RAIN EARLY NEXT WEEK TO THE MIDDLE PART OF THE WEEK...WITH BOTH ECMWF AND GFS CLOSING A LO OFF AND AT THIS POINT SHOW A LARGE DEAL OF UNCERTAINTY ON WHERE TO TRACK IT AND HOW FAST TO DO IT. IT IS WELL WITHIN THE REALM OF POSSIBILITY THAT NO RAIN WILL RESULT FROM THIS IF THE UPPER LO TRACKS TOO FAR S OR IS DELAYED TOO MUCH BUT LEANING TOWARDS THE GFS SOLN SINCE IT WAS THE FIRST TO SHOW THE CUTOFF POTENTIAL AND HAS HAD BETTER RUN-TO-RUN CONSISTENCY. THE GFS SUGGESTS AN EXTENDED PERIOD OF RAIN FROM TUESDAY THRU WEDNESDAY AND HAVE CHC CATEGORY POPS FOR THIS PERIOD. TEMPS APPEAR THEY WILL EDGE CLOSER TO SEASONAL AVERAGES...ESPECIALLY IF RAIN MATERIALIZES...BUT WITH ANOTHER BIG RIDGE READY TO BOUNCE BACK FOR LATE WEEK...TEMPS SHOULD HAVE A FAIRLY EASY TIME STAYING ABOVE AVERAGE. TES && .AVIATION... ISSUED AT 652 AM CDT FRI MAR 30 2012 SURFACE LOW HAS MOVED INTO NORTHEASTERN MO AS OF 11Z...NEAR KUIN AND WILL CONTINUE TO TRACK TO THE EAST WITH ASSOCIATED COLD FRONT SLOWLY SLIDING TO THE SOUTH ACROSS THE FORECAST AREA. CONFIDENCE ON TIMING AND COVERAGE OF ANY SHOWERS AND STORMS THAT DO POP UP ARE HARD TO PIN DOWN...SO KEPT VCSH/CB MENTION FOR SITES ALONG AND EAST OF MISSISSIPPI RIVER...THROUGH MIDDAY. FEEL THAT KCOU SHOULD REMAIN DRY. OTHERWISE...SOUTH WINDS TO BECOME SOUTHWEST...THEN VEER TO THE WEST TO NORTHWEST BEHIND THE FRONTAL BOUNDARY...WITH VFR CIGS. SPECIFICS FOR KSTL...COLD FRONT SLOWLY SLIDING TO THE SOUTH TODAY ACROSS THE FORECAST AREA. CONFIDENCE ON TIMING AND COVERAGE OF ANY SHOWERS AND STORMS THAT DO POP UP ARE HARD TO PIN DOWN...SO KEPT VCSH/CB MENTION BETWEEN 15Z AND 20Z. OTHERWISE...SOUTH WINDS TO BECOME SOUTHWEST...THEN VEER TO THE WEST TO NORTHWEST BEHIND THE FRONTAL BOUNDARY AROUND 20Z...WITH VFR CIGS THROUGHOUT THE FORECAST PERIOD. BYRD && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1156 PM CDT THU MAR 29 2012 .UPDATE... ISSUED AT 949 PM CDT THU MAR 29 2012 CLOUD COVER AND SCATTERED LIGHT SHOWERS SHIFTING E OF THE FORECAST AREA LATE THIS EVNG...WITH A CLEAR SKY FOR MOST OF OUR AREA. CONVECTIVE CLUSTERS MOVING FROM ERN NEBRASKA AND NWRN MO NEWD THROUGH SWRN AND S CNTRL IA IN AREA OF STRONG 850 MB WAA...MOISTURE CONVERGENCE AND THETA E ADVECTION ON NOSE OF SLY LOW LEVEL JET. THIS ACTIVITY WAS ALSO AHEAD OF A SHORTWAVE TROUGH MOVING EWD THROUGH THE NRN PLAINS...AND NEAR AND N-NE OF SFC LOW OVER SERN NEBRASKA AND N OF WARM FRONT EXTENDING SE OF SFC LOW. MOST OF THESE STORMS WERE MOVING EWD OR NEWD. IF ENOUGH OF AN ORGANIZED COLD POOL DEVELOPS COULD SEE SOME OF THIS ACTIVITY DROPPING SEWD. IT APPEARS THAT MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY WILL BE MAINLY CONFINED TO NERN MO AND W CNTRL IL LATE TGT AHEAD OF THE SFC LOW MOVING EWD ALONG THE MO IA BORDER AND N OF THE WARM FRONT EXTENDING SE OF THE SFC LOW. HAD TO LOWER TEMPERATURES OVER NERN MO AND W CNTRL IL WHERE IT HAS FALLEN INTO THE LOWER 50S. TEMPERATURES HERE SHOULD REMAIN NEARLY STEADY OR ACTUALLY RISE A LITTLE OVERNIGHT. GKS && .SHORT TERM... ISSUED AT 204 PM CDT THU MAR 29 2012 (TONIGHT) CONVECTION THAT HAS PERSISTED OVER NORTHWEST MISSOURI THE PAST SEVERAL HOURS HAS SHOWN SLOW EAST SOUTHEASTWARD MOVEMENT IN THE LAST HOUR OR TWO. THIS CONVECTION IS OCCURRING JUST NORTH OF A WARM FRONT FROM THE KANSAS CITY METRO AREA TO SOUTH OF JEFFERSON CITY. THIS FRONT WILL MOVE SLOWLY NORTH THE REST OF THE AFTERNOON INTO TONIGHT IN RESPONSE TO THE TROUGH NOW MOVING EAST INTO THE CENTRAL PLAINS. THE RUC IS SHOWING THAT THE BEST LOW LEVEL MOISTURE CONVERGENCE WILL BE SHIFTING TO THE NORTHEAST WITH TIME...SO WILL CONTINUE WITH SCT SHRA/TSRA BASICALLY ALONG AND NORTH OF I-70 INTO EARLY THIS EVENING. THEREAFTER...WARM FRONT WILL MOVE NORTH THIS EVENING. LOCAL VERSION OF THE WRF AND GFS SHOWS 925-850MB MOISTURE CONVERGENCE MOVING NORTH OF THE AREA THIS EVENING. MORE CONCENTRATED POTENTIAL FOR ADDITIONAL THUNDERSTORMS WILL OCCUR AFTER MIDNIGHT AS A COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH MOVES EASTWARD THROUGH MISSOURI. HAVE KEPT LIKELY POPS OVER NORTHEAST MO/WEST CENTRAL IL WHICH WILL BE CLOSEST TO THE TRACK OF THE ATTENDANT SURFACE LOW... WITH SCATTERED THUNDERSTORMS TO THE SOUTH. MUCAPES IN THE 500-1000 J/KG RANGE AND DEEP LAYER SHEAR OF 30-40KTS SUGGEST THERE MAY STILL BE A FEW STRONG STORMS CAPABLE OF PRODUCING HAIL AND GUSTY WINDS INTO THE OVERNIGHT HOURS. BRITT && .LONG TERM... ISSUED AT 309 PM CDT THU MAR 29 2012 (FRIDAY THROUGH THURSDAY) GUIDANCE MOVES THE SURFACE LOW ACROSS NORTHERN ILLINOIS FRIDAY MORNING WITH THE ATTENDANT WEAK COLD FRONT DROPPING THROUGH THE CWFA INTO SOUTHERN MISSOURI BY 00-06Z SATURDAY. FORECAST SOUNDINGS ARE INDICATING A WEAK CAP WITH MODEST INSTABILITY OF 1000-1500 J/KG. CONVERGENCE ON THE FRONT DOESN`T LOOK VERY IMPRESSIVE...BUT THINK SCATTERED THUNDERSTORMS WILL CONTINUE AS THE FRONT MOVES SOUTH. WIND WILL QUICKLY SHIFT BACK TO THE SOUTH ON SATURDAY ALLOWING TEMPERATURES TO ONCE AGAIN CLIMB INTO THE MID 70S TO LOW 80S. THE GFS IS KICKING OUT A LITTLE OZARK-EFFECT DIURNAL CONVECTION LATE SATURDAY AFTERNOON/EVENING AND THIS LOOKS REASONABLE GIVEN THE PATTERN SO HAVE INCREASED POPS TO SLIGHT CHANCE ACROSS SOUTHERN PORTIONS OF THE AREA. LOW LEVEL JET RAMPS UP LATE SATURDAY NIGHT...ESPECIALLY ACROSS PARTS OF IOWA AND ILLINOIS AND BOTH THE GFS AND NAM ARE PRINTING OUT PRECIP IN THOSE AREAS. LOW LEVEL MOISTURE CONVERGENCE SIGNATURES ARE VERY BROAD AND COULD INDICATE PRECIP ALMOST ANYWHERE IN EASTERN IOWA/WESTERN ILLINOIS. THINK SOME RAIN IS LIKELY SOMEWHERE IN THAT AREA...BUT AM UNSURE WHAT THE COVERAGE...STRENGTH...OR DURATION OF THE CONVECTION WILL BE. HAVE THEREFORE DECIDED TO BE CONSERVATIVE AND ONLY INCREASED POPS TO SLIGHT CHANCE THROUGH 12Z SUNDAY MORNING. WARM ADVECTION CONTINUES SUNDAY WITH 850MB TEMPS BETWEEN 16-18C WHICH SHOULD EASILY PRODUCE HIGHS IN THE LOW TO MID 80S ACROSS THE ENTIRE AREA...UNLESS THE SATURDAY NIGHT CONVECTION IS STRONGER THAN ANTICIPATED AND COOLS THE ATMOSPHERE OFF MORE THAN ANTICIPATED. MEDIUM RANGE MODELS CONTINUE TO BRING A SHARP TROF OUT FROM THE GREAT PLAINS ACROSS THE MIDWEST EARLY NEXT WEEK. WITH THE GULF OPEN AND PLENTY OF MOISTURE AVAILABLE WE SHOULD SEE INCREASING COVERAGE OF CONVECTION MONDAY AND MONDAY NIGHT AHEAD OF THE COLD FRONT ASSOCIATED WITH THIS WAVE. ECMWF IS FASTER AND KEEPS AN OPEN WAVE MOVING THROUGH THE AREA BY LATE MONDAY NIGHT WHILE THE GFS CLOSES THE WAVE OFF AND HOLDS PRECIP BACK OVER THE AREA INTO TUESDAY NIGHT. GEM IS MORE SIMILAR TO THE GFS...SO KEPT CHANCE POPS GOING THROUGH TUESDAY BUT ENDED PRECIP TUESDAY NIGHT. TEMPERATURES WILL FALL CLOSER TO CLIMATOLOGICAL AVERAGE BEHIND THE FRONT WEDNESDAY AND THURSDAY. CARNEY && .AVIATION... ISSUED AT 1138 PM CDT THU MAR 29 2012 THE SURFACE LOW HAS PROGRESSED INTO FAR NW MO WITH THE COLD FRONT TRAILING INTO CENTRAL KS AND WARM FRONT STRETCHING THROUGH WEST CENTRAL MO INTO SE MO. THUNDERSTORMS WHICH FORMED EARLIER ACROSS THE CENTRAL PLAINS HAVE DIMINISHED SIGNIFICANTLY IN COVERAGE WHILE A LARGE THUNDERSTORM COMPLEX WAS CENTERED IN IOWA WITH THE SOUTHERN PORTION POKING INTO NW MO. THE SURFACE LOW WILL TRACK INTO SE IA BY DAYBREAK AND EASTWARD INTO THE OH VALLEY ON FRIDAY. THUNDERSTORM CHANCES OVERNIGHT DEPEND ON WHETHER ANY ACTIVITY FROM THE IOWA COMPLEX WILL SINK FAR ENOUGH SOUTH TO IMPACT KUIN. I CANT RULE IT OUT AT THIS TIME AND WILL KEEP WITH THE CURRENT FORECAST OF VCTS BEGINNING AT 08Z. NOT EXPECTING ANY ACTIVITY FURTHER SOUTH AHEAD OF THE ADVANCING COLD FRONT OVERNIGHT INTO THE FIRST PART OF FRIDAY MORNING. THUNDERSTORMS MAY ATTEMPT TO DEVELOP ALONG THE COLD FRONT BETWEEN 15-19Z FRIDAY AS IT MOVES THROUGH THE ST LOUIS METRO AREA...BUT UNCERTAINTY IS HIGH. SPECIFICS FOR KSTL... TRANQUIL WEATHER EXPECTED OVERNIGHT WITH VFR CONDITIONS DOMINATING. HIGH CLOUDS WILL BE ON THE INCREASE AS A WARM FRONT LIFTS NORTHWARD THROUGH THE AREA. ANY THREAT OF SHOWERS AND THUNDERSTORMS IN THE ST LOUIS AREA SHOULD BE FROM 15Z-19Z FRIDAY ALONG AND AHEAD OF THE ADVANCING COLD FRONT. CONFIDENCE IS TOO LOW TO INCLUDE THIS FAR OUT IN THE FORECAST AND FOR NOW HAVE JUST MENTIONED VCSH AND A CB CLOUD GROUP. GLASS && .PRELIMINARY POINT TEMPS/POPS... ST LOUIS 59 77 53 79 / 40 40 10 10 QUINCY 53 73 50 78 / 60 50 10 10 COLUMBIA 60 76 54 81 / 50 30 10 10 JEFFERSON CITY 60 77 53 81 / 50 30 10 10 SALEM 55 77 50 74 / 20 30 10 10 FARMINGTON 58 77 52 80 / 20 30 10 20 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
314 PM CDT FRI MAR 30 2012 .SHORT TERM...TONIGHT THROUGH MONDAY. SEVERAL PERIODS OF ISOLD/SMALL POP CONVECTION CHANCES DOT SHORT TERM FORECAST LANDSCAPE OTHERWISE TEMPERATURES ARE THE PRIMARY CONCERN. FIRST SMALL PRECIP CHANCE IS EARLY THIS EVENING AS UPPER SHORT WAVE ENERGY PUSHING TOWARD MO RIVER PER AFTERNOON STLT IMAGERY FOCUSES ON CONVERGENT BOUNDARY WHICH AT 19Z STRETCHED FROM YKN- TQE-OMA WITH SECOND CONVERGENT AREA APPROACHING LNK AND OLU. SELECTIVE MODELS...I.E. HRRR+4KM WRF HAVE GENERATED SMALL QPF CLUSTER WHICH PUSHES INTO SWRN IA BEFORE WEAKENING FAIRLY QUICKLY WITH LOSS OF HEATING. MEANWHILE RUC KEPT MID LAYER PRETTY DRY/WELL MIXED CAP AND GFS NOT OVERLY SUPPORTIVE EITHER. WILL EXTEND SMALL POPS ERN ZONES EARLY THIS EVENING...HOWEVER...DUE TO CONVERGENT CU AND OCNL WEAK CELLS THAT HAD CONTD TO DEVELOP ON RADAR IN 19-20Z PERIOD. OTHERWISE FLAT UPPER RIDGING SPREADING ACROSS PLAINS ON SATURDAY WILL BRING EVEN WARMER READINGS TO AREA WITH NEAR RECORD HIGHS LIKELY AT OFK/OMA AND LNK. DID NOT INCLUDE LATE AFTERNOON POPS AT THIS TIME NEAR H85 THERMAL AXIS NEAR OR N OF OMA AND POINTS EWD...BUT CONVECTIVE TEMPERATURES COULD BE REACHED PER NAM FORECAST SOUNDINGS. AREA WILL HAVE TO BE MONITORED...BUT LEFT OUT DUE TO AREA APPEARS WILL EXTEND IN GENERAL UPPER RIDGE AREA. UPPER RIDGE AMPS/SHIFTS EAST A LITTLE SUNDAY SPREADING EVEN WARMER H85 TEMPS OVER AREA. RECORD HIGHS AGAIN APPROACHED MANY LOCATIONS AS IT APPEARS MOST HIGHS SHOULD BE A FEW DEGREES WARMER THAN THOSE EXPECTED ON SATURDAY. LEFT IN SMALL POPS WITH FRONT ON MONDAY ALTHOUGH THERE WAS LITTLE UPPER SUPPORT WITH FRONT PUSHING INTO NEGATIVELY TILTED UPPER RIDGE AS ENERGY SPLITS. HOWEVER...WITH VERY WARM TEMPERATURES AHEAD OF THIS STRONGER COLD FRONT...AND DELAYED TIMING A BIT...DID BOOST MAX TEMPS A CATEGORY OR SO SERN 1/2-2/3RDS OF THE AREA. .LONG TERM...MONDAY NIGHT THROUGH FRIDAY. FOCUS TURNS TO HOW FAR NORTH UPPER LOW WILL DRIFT FOR POSSIBLE PRECIP CHANCES...IF IT LIFTS FAR ENOUGH N...OR FOR POTENTIAL FROST/ISOLD FREEZING TEMPERATURES IF PATTERN DEVELOPS INTO A STALLED REX-LIKE BLOCK WITH UPPER LOW FARTHER SOUTH. ALTHOUGH LOWERED A FEW LOW TEMPERATURES INTO UPPER 30S-40ISH WED AM DID NOT STRAY TOO FAR FROM MODEL BLEND WITH OTHER LOW TEMPS AS TOO MANY UNCERTAINTIES PERSIST. DID ALSO LOWER MAX TEMPS A LITTLE IN WED- THU PERIOD AND SPREAD POPS A LITTLE FARTHER NW MON NIGHT INTO TUE. HOWEVER...ENTIRE PERIOD WILL LIKELY SEE CHANGES...AND AT LEAST MODERATE ONES...AS CONFIDENCE WAS LOW WITH HOW PATTERN WILL DEVELOP. && .AVIATION... 18Z TAFS FOR KOMA...KLNK AND KOFK. VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD. A MID LEVEL SHORTWAVE IS MOVING THROUGH EASTERN NEBRASKA THIS AFTERNOON. THIS COULD SPARK A FEW THUNDERSTORMS...MAINLY BEFORE 7 PM. PEARSON && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ CHERMOK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1155 AM CDT FRI MAR 30 2012 .AVIATION...18Z KGRI TAF. VFR CONDITIONS ARE EXPECTED THROUGHOUT THE ENTIRE TAF PERIOD. AS AN UPPER LEVEL RIDGE BUILDS INTO THE REGION...THE MAIN CONCERN FOR THE TAF PERIOD WILL BE INCREASING WINDS TODAY AS BOUNDARY LAYER MIXING OCCURS. SUSTAINED WINDS NEAR 12 KTS IS CERTAINLY POSSIBLE THROUGHOUT THE AFTERNOON HOURS. A FEW MID TO HIGH CLOUDS ARE EXPECTED DURING THE TAF PERIOD AS THE UPPER LEVEL JET WRAPS AROUND THE TOP OF THE RIDGE. WINDS WILL BECOME LIGHT THIS EVENING BEFORE INCREASING AGAIN SATURDAY MORNING FROM THE SOUTHWEST. && PREV DISCUSSION... /ISSUED 328 AM CDT FRI MAR 30 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT. A FAIRLY PROGRESSIVE ZONAL FLOW PATTERN WAS IN PLACE ACROSS THE CENTRAL PLAINS WITH ONE SHORTWAVE TRANSLATING TO OUR EAST...EAST OF THE MISSOURI RIVER...WITH ANOTHER UPSTREAM SHORTWAVE TROUGH LOCATED IN EASTERN WY/CO. CURRENTLY AT THE SURFACE...LOW PRESSURE WAS CENTERED IN NORTHWEST MISSOURI WITH COOL FRONTAL BOUNDARY STRETCHING THROUGH CENTRAL KANSAS. SFC DPS REMAIN HIGH ALONG THE MISSOURI RIVER INTO NORTH CENTRAL AND EASTERN KANSAS WITH READINGS IN THE 50S TO AROUND 60F AND HRRR SUGGESTS SOME FOG DEVELOPMENT ACROSS NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA OR JUST ON THE PERIPHERY OF OUR SOUTHEAST CWA. OBSERVATION AT 08Z AT BELOIT SHOWED VSBY DROPPED TO ONE QUARTER MILE AND IF TRENDS CONTINUE FOG HEADLINE WILL BE WARRANTED. AFOREMENTIONED UPSTREAM SHORTWAVE WILL CROSS OUR CWA AROUND MIDDAY/EARLY AFTERNOON WITH NEGLIGIBLE EFFECT OTHER THAN INCREASING CLOUD COVER AND WIND SHIFT TO A MORE WESTERLY DIRECTION AS ASSOCIATED SURFACE TROUGH SLIDES EAST. CONVECTIVE TEMPS ARE IN THE MID 70S THIS AFTERNOON AND EXPECT SOME MID LEVEL CU DEVELOPMENT THIS AFTERNOON WHICH LOOKS TO SLOW TEMP RISE THIS AFTERNOON AND LOWERED MAX TEMPS BY JUST A DEGREE OR TWO. MODEL FORECAST SOUNDINGS SUGGEST DEEP MIXING ACROSS OUR WESTERN CWA WITH SFC DPS DROPPING TO THE 30S THIS AFTN. LOW RELATIVE HUMIDITIES ACROSS OUR WESTERN CWA...MAINLY DAWSON COUNTY...DROP NEAR 20 PERCENT THIS AFTERNOON. WIND SPEEDS DO NOT APPEAR EXTREMELY STRONG BUT GUSTS OVER 20 MPH CANNOT BE RULED OUT AND RIGHT NOW CONDITIONS APPEAR CLOSE BUT NOT QUITE AT FIRE WEATHER CRITERIA...HOWEVER WILL NEED TO MONITOR CONDITIONS CLOSELY THIS AFTN IN WESTERN ZONES. HEADING INTO THE WEEKEND...DRY AND WARM...OR SHALL WE SAY HOT CONDITIONS FOR LATE MARCH/EARLY APRIL WILL SETTLE INTO OUR REGION. HEIGHTS RISE TONIGHT BEHIND DEPARTING SHORTWAVE TROUGH...WITH UPPER RIDGING BUILDING ACROSS THE CENTRAL PLAINS ON SATURDAY AHEAD OF AN UPPER TROUGH DEEPENING ALONG THE WEST COAST. THE RIDGE REMAINS IN PLACE ACROSS THE CENTRAL PLAINS EARLY SUNDAY BEFORE FLOW TRANSITIONS SOUTHWESTERLY BY AFTERNOON AS UPPER TROUGH MOVES INTO THE ROCKIES. H85 TEMPS ARE RIGHT AROUND 20C BOTH SATURDAY AND SUNDAY AND FORECAST SOUNDINGS SUGGEST MIXING WILL BE EVEN HIGHER THAN H85. HAVE MAINTAINED UPPER 80S FOR HIGHS ON SATURDAY WITH A DRIER AIRMASS IN PLACE AND WARMING AIDED BY DOWNSLOPE WIND COMPONENT. BY SUNDAY LLVL FLOW TRANSITIONS SOUTHERLY WITH SFC CYCLOGENESIS ALONG THE HIGH PLAINS AND MOISTURE RETURNS NORTH WITH DPS RETURNING TO THE 50S. CURRENTLY HAVE HIGHS FORECAST IN THE MID/UPPER 80S FOR SUNDAY. RECORD HIGHS BOTH SATURDAY AND SUNDAY ARE IN THE 88 TO 90 RANGE FOR GRAND ISLAND...HASTINGS AND KEARNEY...AND WE WILL BE RIGHT NEAR THERE. SATURDAY WILL BE A DAY TO MONITOR FOR FIRE WEATHER CONCERNS AS WELL AS A LARGER PORTION OF OUR CWA WILL SEE LOW RELATIVE HUMIDITIES BELOW 20 PERCENT...BUT THAT BEING SAID...WINDS ARE NOT LOOKING OVERLY STRONG AT THIS POINT. UPPER TROUGH CONTINUES TO DEEPEN IN THE SOUTHERN ROCKIES SUNDAY NIGHT AND FRONTAL PROGRESSION HAS SLOWED. WITH SLOWER FROPA...HAVE RAISED LOW TEMPS QUITE A BIT AS DPS LOOK TO HOLD IN THE 50S FOR THE MOST PART THROUGH THE NIGHT. WITH FRONT MAINLY TO OUR WEST OR ON THE PERIPHERY OF OUR WESTERN COUNTIES...HAVE REMOVED POPS FOR THIS TIME FRAME. LONG TERM...STARTING 12Z MONDAY. GUIDANCE SUGGESTS A MID LEVEL LOW WILL PUSH ACROSS THE SOUTHERN PLAINS DURING THE DAY MONDAY...WITH A MID LEVEL SHORT WAVE ALSO PUSHING ACROSS THE CENTRAL AND NORTHERN PLAINS ON MONDAY. AN ASSOCIATED LOW LEVEL BAROCLINIC ZONE IS ALSO EXPECTED TO CLEAR OUR CWA EARLY MONDAY. ALTHOUGH THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO WHEN THE SURFACE FRONT WILL ACTUALLY CLEAR THE AREA...INCREASED VALUES OF LOW LEVEL MOISTURE AHEAD OF THE FRONT WILL STILL PROMOTE ENOUGH INSTABILITY FOR CONVECTIVE DEVELOPMENT AND WITH QPF FIELDS FROM THE OPERATIONAL GFS STILL SUGGESTING PRECIPITATION WILL BE REALIZED ACROSS OUR EAST ON MONDAY...WILL GO AHEAD AND CONTINUE CARRYING SLIGHT CHANCES POPS ACROSS OUR EAST FOR MONDAY. THE MID LEVEL LOW OVER THE SOUTHERN PLAINS IS THEN EXPECTED TO LIFT TO THE NORTHEAST MONDAY NIGHT...WITH PERHAPS ENOUGH MID LEVEL THERMAL ADVECTION TO THE EAST AND NORTHEAST OF THE LOW FOR PRECIPITATION PRODUCTION ACROSS PORTIONS OF OUR CWA MONDAY NIGHT INTO TUESDAY AND AS A RESULT...WENT AHEAD AND CONTINUED SLIGHT CHANCE POPS ACROSS MUCH OF THE CWA MONDAY NIGHT INTO TUESDAY. AN OVERALL LACK IN KINEMATIC FORCING DUE TO STRENGTHENING UPPER LEVEL RIDGING ACROSS THE CENTRAL CONUS SHOULD KEEP US DRY TUESDAY NIGHT THROUGH THURSDAY. RELATIVELY COOLER WEATHER WILL BE OBSERVED DURING MUCH OF THE EXTENDED FORECAST PERIOD AS A COOLER AIRMASS INFILTRATES OUR AREA POST-FROPA ON MONDAY. THAT BEING SAID...TEMPERATURES ARE STILL EXPECTED TO REMAIN AT ABOVE-NORMAL LEVELS WITH HIGHS GENERALLY IN THE 60S AND 70S...AND LOWS GENERALLY IN THE 30S AND 40S. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
607 AM CDT FRI MAR 30 2012 .AVIATION...12Z KGRI TAF. VFR CONDITIONS WILL CONTINUE THROUGH THE NEXT 24 HOURS. MID TO HIGH LEVEL CLOUDS WILL BE ON THE INCREASE BUT NOTHING LOWER THAN 10000FT AGL IS CURRENTLY EXPECTED. SURFACE WINDS WILL BECOME MORE ESTABLISHED FROM THE SOUTHWEST TODAY. VISIBILITY RESTRICTIONS ARE NOT EXPECTED THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 328 AM CDT FRI MAR 30 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT. A FAIRLY PROGRESSIVE ZONAL FLOW PATTERN WAS IN PLACE ACROSS THE CENTRAL PLAINS WITH ONE SHORTWAVE TRANSLATING TO OUR EAST...EAST OF THE MISSOURI RIVER...WITH ANOTHER UPSTREAM SHORTWAVE TROUGH LOCATED IN EASTERN WY/CO. CURRENTLY AT THE SURFACE...LOW PRESSURE WAS CENTERED IN NORTHWEST MISSOURI WITH COOL FRONTAL BOUNDARY STRETCHING THROUGH CENTRAL KANSAS. SFC DPS REMAIN HIGH ALONG THE MISSOURI RIVER INTO NORTH CENTRAL AND EASTERN KANSAS WITH READINGS IN THE 50S TO AROUND 60F AND HRRR SUGGESTS SOME FOG DEVELOPMENT ACROSS NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA OR JUST ON THE PERIPHERY OF OUR SOUTHEAST CWA. OBSERVATION AT 08Z AT BELOIT SHOWED VSBY DROPPED TO ONE QUARTER MILE AND IF TRENDS CONTINUE FOG HEADLINE WILL BE WARRANTED. AFOREMENTIONED UPSTREAM SHORTWAVE WILL CROSS OUR CWA AROUND MIDDAY/EARLY AFTERNOON WITH NEGLIGIBLE EFFECT OTHER THAN INCREASING CLOUD COVER AND WIND SHIFT TO A MORE WESTERLY DIRECTION AS ASSOCIATED SURFACE TROUGH SLIDES EAST. CONVECTIVE TEMPS ARE IN THE MID 70S THIS AFTERNOON AND EXPECT SOME MID LEVEL CU DEVELOPMENT THIS AFTERNOON WHICH LOOKS TO SLOW TEMP RISE THIS AFTERNOON AND LOWERED MAX TEMPS BY JUST A DEGREE OR TWO. MODEL FORECAST SOUNDINGS SUGGEST DEEP MIXING ACROSS OUR WESTERN CWA WITH SFC DPS DROPPING TO THE 30S THIS AFTN. LOW RELATIVE HUMIDITIES ACROSS OUR WESTERN CWA...MAINLY DAWSON COUNTY...DROP NEAR 20 PERCENT THIS AFTERNOON. WIND SPEEDS DO NOT APPEAR EXTREMELY STRONG BUT GUSTS OVER 20 MPH CANNOT BE RULED OUT AND RIGHT NOW CONDITIONS APPEAR CLOSE BUT NOT QUITE AT FIRE WEATHER CRITERIA...HOWEVER WILL NEED TO MONITOR CONDITIONS CLOSELY THIS AFTN IN WESTERN ZONES. HEADING INTO THE WEEKEND...DRY AND WARM...OR SHALL WE SAY HOT CONDITIONS FOR LATE MARCH/EARLY APRIL WILL SETTLE INTO OUR REGION. HEIGHTS RISE TONIGHT BEHIND DEPARTING SHORTWAVE TROUGH...WITH UPPER RIDGING BUILDING ACROSS THE CENTRAL PLAINS ON SATURDAY AHEAD OF AN UPPER TROUGH DEEPENING ALONG THE WEST COAST. THE RIDGE REMAINS IN PLACE ACROSS THE CENTRAL PLAINS EARLY SUNDAY BEFORE FLOW TRANSITIONS SOUTHWESTERLY BY AFTERNOON AS UPPER TROUGH MOVES INTO THE ROCKIES. H85 TEMPS ARE RIGHT AROUND 20C BOTH SATURDAY AND SUNDAY AND FORECAST SOUNDINGS SUGGEST MIXING WILL BE EVEN HIGHER THAN H85. HAVE MAINTAINED UPPER 80S FOR HIGHS ON SATURDAY WITH A DRIER AIRMASS IN PLACE AND WARMING AIDED BY DOWNSLOPE WIND COMPONENT. BY SUNDAY LLVL FLOW TRANSITIONS SOUTHERLY WITH SFC CYCLOGENESIS ALONG THE HIGH PLAINS AND MOISTURE RETURNS NORTH WITH DPS RETURNING TO THE 50S. CURRENTLY HAVE HIGHS FORECAST IN THE MID/UPPER 80S FOR SUNDAY. RECORD HIGHS BOTH SATURDAY AND SUNDAY ARE IN THE 88 TO 90 RANGE FOR GRAND ISLAND...HASTINGS AND KEARNEY...AND WE WILL BE RIGHT NEAR THERE. SATURDAY WILL BE A DAY TO MONITOR FOR FIRE WEATHER CONCERNS AS WELL AS A LARGER PORTION OF OUR CWA WILL SEE LOW RELATIVE HUMIDITIES BELOW 20 PERCENT...BUT THAT BEING SAID...WINDS ARE NOT LOOKING OVERLY STRONG AT THIS POINT. UPPER TROUGH CONTINUES TO DEEPEN IN THE SOUTHERN ROCKIES SUNDAY NIGHT AND FRONTAL PROGRESSION HAS SLOWED. WITH SLOWER FROPA...HAVE RAISED LOW TEMPS QUITE A BIT AS DPS LOOK TO HOLD IN THE 50S FOR THE MOST PART THROUGH THE NIGHT. WITH FRONT MAINLY TO OUR WEST OR ON THE PERIPHERY OF OUR WESTERN COUNTIES...HAVE REMOVED POPS FOR THIS TIME FRAME. LONG TERM...STARTING 12Z MONDAY. GUIDANCE SUGGESTS A MID LEVEL LOW WILL PUSH ACROSS THE SOUTHERN PLAINS DURING THE DAY MONDAY...WITH A MID LEVEL SHORT WAVE ALSO PUSHING ACROSS THE CENTRAL AND NORTHERN PLAINS ON MONDAY. AN ASSOCIATED LOW LEVEL BAROCLINIC ZONE IS ALSO EXPECTED TO CLEAR OUR CWA EARLY MONDAY. ALTHOUGH THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO WHEN THE SURFACE FRONT WILL ACTUALLY CLEAR THE AREA...INCREASED VALUES OF LOW LEVEL MOISTURE AHEAD OF THE FRONT WILL STILL PROMOTE ENOUGH INSTABILITY FOR CONVECTIVE DEVELOPMENT AND WITH QPF FIELDS FROM THE OPERATIONAL GFS STILL SUGGESTING PRECIPITATION WILL BE REALIZED ACROSS OUR EAST ON MONDAY...WILL GO AHEAD AND CONTINUE CARRYING SLIGHT CHANCES POPS ACROSS OUR EAST FOR MONDAY. THE MID LEVEL LOW OVER THE SOUTHERN PLAINS IS THEN EXPECTED TO LIFT TO THE NORTHEAST MONDAY NIGHT...WITH PERHAPS ENOUGH MID LEVEL THERMAL ADVECTION TO THE EAST AND NORTHEAST OF THE LOW FOR PRECIPITATION PRODUCTION ACROSS PORTIONS OF OUR CWA MONDAY NIGHT INTO TUESDAY AND AS A RESULT...WENT AHEAD AND CONTINUED SLIGHT CHANCE POPS ACROSS MUCH OF THE CWA MONDAY NIGHT INTO TUESDAY. AN OVERALL LACK IN KINEMATIC FORCING DUE TO STRENGTHENING UPPER LEVEL RIDGING ACROSS THE CENTRAL CONUS SHOULD KEEP US DRY TUESDAY NIGHT THROUGH THURSDAY. RELATIVELY COOLER WEATHER WILL BE OBSERVED DURING MUCH OF THE EXTENDED FORECAST PERIOD AS A COOLER AIRMASS INFILTRATES OUR AREA POST-FROPA ON MONDAY. THAT BEING SAID...TEMPERATURES ARE STILL EXPECTED TO REMAIN AT ABOVE-NORMAL LEVELS WITH HIGHS GENERALLY IN THE 60S AND 70S...AND LOWS GENERALLY IN THE 30S AND 40S. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...FAY AVIATION/LONG TERM...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
328 AM CDT FRI MAR 30 2012 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT. A FAIRLY PROGRESSIVE ZONAL FLOW PATTERN WAS IN PLACE ACROSS THE CENTRAL PLAINS WITH ONE SHORTWAVE TRANSLATING TO OUR EAST...EAST OF THE MISSOURI RIVER...WITH ANOTHER UPSTREAM SHORTWAVE TROUGH LOCATED IN EASTERN WY/CO. CURRENTLY AT THE SURFACE...LOW PRESSURE WAS CENTERED IN NORTHWEST MISSOURI WITH COOL FRONTAL BOUNDARY STRETCHING THROUGH CENTRAL KANSAS. SFC DPS REMAIN HIGH ALONG THE MISSOURI RIVER INTO NORTH CENTRAL AND EASTERN KANSAS WITH READINGS IN THE 50S TO AROUND 60F AND HRRR SUGGESTS SOME FOG DEVELOPMENT ACROSS NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA OR JUST ON THE PERIPHERY OF OUR SOUTHEAST CWA. OBSERVATION AT 08Z AT BELOIT SHOWED VSBY DROPPED TO ONE QUARTER MILE AND IF TRENDS CONTINUE FOG HEADLINE WILL BE WARRANTED. AFOREMENTIONED UPSTREAM SHORTWAVE WILL CROSS OUR CWA AROUND MIDDAY/EARLY AFTERNOON WITH NEGLIGIBLE EFFECT OTHER THAN INCREASING CLOUD COVER AND WIND SHIFT TO A MORE WESTERLY DIRECTION AS ASSOCIATED SURFACE TROUGH SLIDES EAST. CONVECTIVE TEMPS ARE IN THE MID 70S THIS AFTERNOON AND EXPECT SOME MID LEVEL CU DEVELOPMENT THIS AFTERNOON WHICH LOOKS TO SLOW TEMP RISE THIS AFTERNOON AND LOWERED MAX TEMPS BY JUST A DEGREE OR TWO. MODEL FORECAST SOUNDINGS SUGGEST DEEP MIXING ACROSS OUR WESTERN CWA WITH SFC DPS DROPPING TO THE 30S THIS AFTN. LOW RELATIVE HUMIDITIES ACROSS OUR WESTERN CWA...MAINLY DAWSON COUNTY...DROP NEAR 20 PERCENT THIS AFTERNOON. WIND SPEEDS DO NOT APPEAR EXTREMELY STRONG BUT GUSTS OVER 20 MPH CANNOT BE RULED OUT AND RIGHT NOW CONDITIONS APPEAR CLOSE BUT NOT QUITE AT FIRE WEATHER CRITERIA...HOWEVER WILL NEED TO MONITOR CONDITIONS CLOSELY THIS AFTN IN WESTERN ZONES. HEADING INTO THE WEEKEND...DRY AND WARM...OR SHALL WE SAY HOT CONDITIONS FOR LATE MARCH/EARLY APRIL WILL SETTLE INTO OUR REGION. HEIGHTS RISE TONIGHT BEHIND DEPARTING SHORTWAVE TROUGH...WITH UPPER RIDGING BUILDING ACROSS THE CENTRAL PLAINS ON SATURDAY AHEAD OF AN UPPER TROUGH DEEPENING ALONG THE WEST COAST. THE RIDGE REMAINS IN PLACE ACROSS THE CENTRAL PLAINS EARLY SUNDAY BEFORE FLOW TRANSITIONS SOUTHWESTERLY BY AFTERNOON AS UPPER TROUGH MOVES INTO THE ROCKIES. H85 TEMPS ARE RIGHT AROUND 20C BOTH SATURDAY AND SUNDAY AND FORECAST SOUNDINGS SUGGEST MIXING WILL BE EVEN HIGHER THAN H85. HAVE MAINTAINED UPPER 80S FOR HIGHS ON SATURDAY WITH A DRIER AIRMASS IN PLACE AND WARMING AIDED BY DOWNSLOPE WIND COMPONENT. BY SUNDAY LLVL FLOW TRANSITIONS SOUTHERLY WITH SFC CYCLOGENESIS ALONG THE HIGH PLAINS AND MOISTURE RETURNS NORTH WITH DPS RETURNING TO THE 50S. CURRENTLY HAVE HIGHS FORECAST IN THE MID/UPPER 80S FOR SUNDAY. RECORD HIGHS BOTH SATURDAY AND SUNDAY ARE IN THE 88 TO 90 RANGE FOR GRAND ISLAND...HASTINGS AND KEARNEY...AND WE WILL BE RIGHT NEAR THERE. SATURDAY WILL BE A DAY TO MONITOR FOR FIRE WEATHER CONCERNS AS WELL AS A LARGER PORTION OF OUR CWA WILL SEE LOW RELATIVE HUMIDITIES BELOW 20 PERCENT...BUT THAT BEING SAID...WINDS ARE NOT LOOKING OVERLY STRONG AT THIS POINT. UPPER TROUGH CONTINUES TO DEEPEN IN THE SOUTHERN ROCKIES SUNDAY NIGHT AND FRONTAL PROGRESSION HAS SLOWED. WITH SLOWER FROPA...HAVE RAISED LOW TEMPS QUITE A BIT AS DPS LOOK TO HOLD IN THE 50S FOR THE MOST PART THROUGH THE NIGHT. WITH FRONT MAINLY TO OUR WEST OR ON THE PERIPHERY OF OUR WESTERN COUNTIES...HAVE REMOVED POPS FOR THIS TIME FRAME. .LONG TERM...STARTING 12Z MONDAY. GUIDANCE SUGGESTS A MID LEVEL LOW WILL PUSH ACROSS THE SOUTHERN PLAINS DURING THE DAY MONDAY...WITH A MID LEVEL SHORT WAVE ALSO PUSHING ACROSS THE CENTRAL AND NORTHERN PLAINS ON MONDAY. AN ASSOCIATED LOW LEVEL BAROCLINIC ZONE IS ALSO EXPECTED TO CLEAR OUR CWA EARLY MONDAY. ALTHOUGH THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO WHEN THE SURFACE FRONT WILL ACTUALLY CLEAR THE AREA...INCREASED VALUES OF LOW LEVEL MOISTURE AHEAD OF THE FRONT WILL STILL PROMOTE ENOUGH INSTABILITY FOR CONVECTIVE DEVELOPMENT AND WITH QPF FIELDS FROM THE OPERATIONAL GFS STILL SUGGESTING PRECIPITATION WILL BE REALIZED ACROSS OUR EAST ON MONDAY...WILL GO AHEAD AND CONTINUE CARRYING SLIGHT CHANCES POPS ACROSS OUR EAST FOR MONDAY. THE MID LEVEL LOW OVER THE SOUTHERN PLAINS IS THEN EXPECTED TO LIFT TO THE NORTHEAST MONDAY NIGHT...WITH PERHAPS ENOUGH MID LEVEL THERMAL ADVECTION TO THE EAST AND NORTHEAST OF THE LOW FOR PRECIPITATION PRODUCTION ACROSS PORTIONS OF OUR CWA MONDAY NIGHT INTO TUESDAY AND AS A RESULT...WENT AHEAD AND CONTINUED SLIGHT CHANCE POPS ACROSS MUCH OF THE CWA MONDAY NIGHT INTO TUESDAY. AN OVERALL LACK IN KINEMATIC FORCING DUE TO STRENGTHENING UPPER LEVEL RIDGING ACROSS THE CENTRAL CONUS SHOULD KEEP US DRY TUESDAY NIGHT THROUGH THURSDAY. RELATIVELY COOLER WEATHER WILL BE OBSERVED DURING MUCH OF THE EXTENDED FORECAST PERIOD AS A COOLER AIRMASS INFILTRATES OUR AREA POST-FROPA ON MONDAY. THAT BEING SAID...TEMPERATURES ARE STILL EXPECTED TO REMAIN AT ABOVE-NORMAL LEVELS WITH HIGHS GENERALLY IN THE 60S AND 70S...AND LOWS GENERALLY IN THE 30S AND 40S. && .AVIATION...06Z KGRI TAF. VFR CONDITIONS TO CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS. INCREASING HIGH LEVEL CLOUDS WILL BE OBSERVED...BUT NOTHING BELOW 10000FT AGL IS CURRENTLY EXPECTED. SURFACE WINDS WILL REMAIN LIGHT AND VARIABLE TONIGHT...INCREASING FROM THE SOUTHWEST DURING THE DAY FRIDAY. VISIBILITY RESTRICTIONS ARE NOT EXPECTED THROUGH THE NEXT 24 HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...FAY LONG TERM...BRYANT AVATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1206 AM CDT FRI MAR 30 2012 .AVIATION...06Z KGRI TAF. VFR CONDITIONS TO CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS. INCREASING HIGH LEVEL CLOUDS WILL BE OBSERVED...BUT NOTHING BELOW 10000FT AGL IS CURRENTLY EXPECTED. SURFACE WINDS WILL REMAIN LIGHT AND VARIABLE TONIGHT...INCREASING FROM THE SOUTHWEST DURING THE DAY FRIDAY. VISIBILITY RESTRICTIONS ARE NOT EXPECTED THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 342 PM CDT THU MAR 29 2012/ SHORT TERM...THROUGH FRIDAY. MAIN FORECAST CONCERN WILL BE THUNDERSTORMS THIS AFTERNOON. STRATUS HAS BEEN PERSISTENT ACROSS THE CENTRAL PART OF THE FORECAST AREA MUCH OF THE DAY...WHILE THE NORTH AND SOUTH HAVE HAD SOME CLEARING. THE LATEST TREND IN THE RADAR HAS SOME WEAK SHOWERY TYPE PRECIPITATION FORMING UNDER THE STRATUS. THUNDERSTORMS THAT HAD DEVELOPED IN NORTH CENTRAL NEBRASKA EARLIER HAVE DECREASED TO WEAK SHOWERS. SURFACE ANALYSIS SHOWS THE SURFACE LOW IN CENTRAL KANSAS WITH A BOUNDARY EXTENDING TO THE NORTH THROUGH THE FORECAST AREA. THE BOUNDARY IS MORE OF A BROAD TROUGH THAN A REAL COLD FRONT. WINDS SWITCH FROM EASTERLY TO NORTHERLY AS THE TROUGH GOES PAST...BUT THE DRIER AIR AND WIND INCREASE IS FURTHER TO THE WEST. THE UPPER LEVEL WAVE AND SURFACE BOUNDARY WILL CONTINUE TO MOVE TO THE EAST. THEY WILL PUSH THROUGH THE EASTERN HALF OF THE FORECAST AREA DURING THE REMAINDER OF THE AFTERNOON AND SHOULD BE TO THE EAST BY EVENING. THE MODELS CONTINUE TO HAVE SOME SHOWERS AND THUNDERSTORMS DEVELOP LATE THIS AFTERNOON AS THE FRONT MOVES THROUGH THE AREA. THE 00Z 4KM WRF AND THE HRRR DEVELOP SOME SHOWERS AND THUNDERSTORMS ALONG AND JUST BEHIND THE FRONT LATE THIS AFTERNOON. WILL KEEP CHANCES FOR THUNDERSTORMS ACROSS THE AREA...BUT THE BEST CHANCE WILL BE IN THE NORTHEAST WHERE THE UPPER WAVE IS STRONGEST. MUCAPE IS 1500 TO 2000 J/KG SO THERE COULD BE SOME STRONG TO SEVERE THUNDERSTORMS. ONCE THE BOUNDARY MOVES TO THE EAST THE CHANCES FOR THUNDERSTORMS DROPS OFF AND HAVE KEPT THE FORECAST DRY FOR THIS EVENING. THE PRECIPITATION SHOULD BE TO THE EAST OF THE FORECAST AREA BY EVENING. BY LATE TONIGHT A SURFACE HIGH PRESSURE SYSTEM BUILDS INTO THE AREA AND SKIES BECOME MOSTLY CLEAR TO PARTLY CLOUDY. ON FRIDAY THERE IS WARM ADVECTION SO THE TEMPERATURES SHOULD WARM UP FROM TODAY. LONG TERM...SATURDAY THROUGH THURSDAY. FOR MUCH OF THE MID TERM PERIOD...SATURDAY AND SUNDAY...THE CENTRAL PLAINS REMAIN CENTERED UNDER A WEAK RIDGE...WITH FAIRLY ZONAL FLOW ACROSS THE REGION. NO PRECIPITATION IS EXPECTED THROUGH THE MID TERM PERIOD. DECIDED TO BUMP UP TEMPERATURES SLIGHTLY BOTH SATURDAY AND SUNDAY AS GUIDANCE IS A FEW DEGREES IN HIGHER IN BOTH THE NAM AND THE GFS. 850 TEMPERATURES NEAR 20 DEGREES CELSIUS BOTH DAYS SHOULD WARM UP THE AREA QUITE NICELY. BEGINNING THE EXTENDED PERIOD SUNDAY NIGHT...AN UPPER LEVEL TROUGH CONTINUES TO PUSH OFF THE WEST COAST TOWARDS THE COLORADO ROCKIES. THE GFS IS DEEPER THAN THE NAM SOLUTION WITH THIS TROUGH...WHILE BOTH MODELS SUGGEST SURFACE LOW PRESSURE STRETCHING FROM THE WESTERN PORTION OF THE PLAINS INTO CANADA SUNDAY NIGHT. AS THE PRESSURE SYSTEMS PUSH THROUGH THE REGION SUNDAY NIGHT INTO MONDAY MORNING...BOTH MODELS SUGGEST THE POSSIBILITY FOR THUNDERSTORM CHANCES OVERNIGHT AHEAD OF THE SURFACE BOUNDARY. THE EC REMAINS THE FASTER OF THE TWO SOLUTIONS WITH THE FRONT COMPLETELY THROUGH THE FORECAST AREA BY 12Z...WHILE THE GFS PUSHES THE FRONT ABOUT HALFWAY THROUGH BY 12Z. THAT BEING SAID...BOTH MODELS ARE SUGGESTING A VERY TIGHT PRESSURE GRADIENT BEHIND THE FRONT AND PRESSURE RISES OF 15 TO 20 MB ACROSS THE FORECAST AREA. THE MAIN CONCERN WILL BE WITH THE TIMING OF THE INCREASED WINDS BEHIND THE FRONT...WHILE THE EC INCREASES WINDS BY THE 6Z TO 12Z TIME RANGE...THE GFS LAGS A BIT BEHIND AND INCREASES WINDS TOWARDS THE MORNING AND AFTERNOON HOURS ON MONDAY. SUSTAINED NORTHWEST WINDS NEAR 25 TO 30 MILES PER HOUR WITH WIND GUSTS NEAR 30 TO 35 MILES PER HOUR CAN BE EXPECTED BEHIND THE FRONT. DRY AIR BEHIND THE FRONT WILL HELP REDUCE DEWPOINTS ACROSS THE REGION...IN COMBINATION WITH HIGHER WINDS ON MONDAY...RELATIVE HUMIDITY VALUES WILL NEED TO BE WATCHED AS THEY ARE CURRENTLY FORECAST TO BE IN THE LOWER 20S ACROSS THE WEST. SHOULD HIGH TEMPERATURES INCREASE OR DEWPOINTS DECREASE JUST SLIGHTLY...FIRE WEATHER MAY BE A CONCERN ON MONDAY AFTERNOON. AS THE TROUGH TRIES TO PUSH OUT OF THE REGION MONDAY EVENING...THE EC BEGINS TO BRING IN AN UPPER LEVEL RIDGE AND SURFACE HIGH PRESSURE SYSTEM IMMEDIATELY FOLLOWING...WHILE THE GFS TAKES A BIT SLOWER TO MOVE OUT AND PRODUCES A CUT OFF LOW AT THE UPPER LEVELS AND A STRONGER SURFACE LOW ACROSS OKLAHOMA AND ARKANSAS BEFORE PUSHING OUT OF THE REGION BY TUESDAY EVENING. COOLER TEMPERATURES ARE EXPECTED ACROSS THE PLAINS BOTH MONDAY AND TUESDAY WITH HIGHS IN THE 60S. BOTH MODELS KEEP THE CENTRAL PLAINS UNDER AN UPPER LEVEL RIDGE AND SURFACE HIGH THROUGH THE END OF THE LONG TERM WITH SOUTHERLY WINDS AND HIGH TEMPERATURES IN THE LOW TO MID 70S WEDNESDAY AND THURSDAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS ELKO NV
311 PM PDT FRI MAR 30 2012 .SYNOPSIS...VERY STRONG WINDS WILL IMPACT THE REGION TOMORROW AHEAD OF A STRONG SURFACE COLD FRONT. BLOWING DUST AND A FEW ISOLATED THUNDERSTORMS WILL DEVELOP AHEAD OF THE FRONT. SATURDAY NIGHT TEMPERATURES WILL RAPIDLY DROP BEHIND THE FRONT WITH SCATTERED SNOW SHOWERS EXPECTED DURING THE DAY ON SUNDAY. WARMING TREND AND DRIER WEATHER IS EXPECTED FOR THE BEGINNING OF NEXT WEEK. && .SHORT TERM...TONIGHT THROUGH MONDAY. CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A STRONG PACIFIC NORTHWEST JET MAX OF 130KTS AHEAD OF A DIGGING PACIFIC 500MB TROUGH. THE UPPER LEVEL JET WILL CONTINUE TO PROGRESS EASTWARD INTO THE GREAT BASIN TONIGHT. STILL LOOKING LIKE AN IMPRESSIVE WIND EVENT DURING THE DAY TOMORROW ACROSS ALL ZONES. ALL HIGH WIND INDICES ARE LOOKING GOOD WITH 700/500MB WIND ANOMALIES OF +3 TO 4 STANDARD DEVIATIONS...MAV GUIDANCE FOR ALL TAF LOCATIONS IS SHOWING SOLID 32-38KTS...MIXING HEIGHTS ARE FORECASTED TO REACH 550MB...AND A 993 SURFACE LOW OVER SOUTHERN IDAHO WILL HELP ENHANCE LOW LEVEL NORTH/SOUTH CHANNELING OF WINDS. HAVE UPGRADED ALL ZONES TO A HIGH WIND WARNING FROM THE ONGOING WATCH. WILL MOST LIKELY HAVE SOME BLOWING DUST TOMORROW WITH THE PROLONGED WIDE SPREAD WINDS. IN ADDITION THERE COULD BE A FEW ISOLATED STRIKES DURING THE AFTERNOON HOURS ALONG THE ID/OR/NV BORDER. SATURDAY NIGHT THE FRONT WILL PUSH THROUGH THE AREA...WITH A VERY TIGHT TEMP GRADIENT BEHIND THE FRONT. SHOULD SEE 20-30 DEGREE TEMPS DROPS IN JUST A FEW HOURS BEHIND THE FRONT. PRECIP IS STILL TRENDING LIGHT BEHIND THE FRONT...SO KEPT QPF AND SNOW AMOUNTS ON THE LOW SIDE. MOST AREA WILL ONLY SEE A FEW HUNDREDTHS OF LIQUID WITH MAYBE A TRACE OF SNOW ABOVE 5500FT. THERE STILL COULD BE A FEW INCHES ACROSS THE MOUNTAINS OF EASTERN NV BY DAYBREAK SUNDAY. SUNDAY A COLD UPPER LEVEL 500MB TROUGH WILL BE CENTERED OVER THE REGION...LEADING TO STEEP LOW LEVEL LAPSE RATES. CONVECTIVE SNOW SHOWERS WILL CONTINUE THROUGH THE DAY...WITH A FEW ADDITIONAL INCHES OF ACCUMULATIONS ACROSS THE MOUNTAINS...ONLY A DUSTING IS EXPECTED ACROSS THE WARMER VALLEYS. WARMER IS RELATIVE AS HIGHS ARE ONLY EXPECTED TO REACH THE LOW TO MID 40S ACROSS THE VALLEYS WITH BELOW ZERO TEMPS IN THE MOUNTAINS. RIDGING QUICKLY RETURNS BY MONDAY...BRINGING A NICE DAY WITH MOSTLY CLEAR SKIES AND TEMPS REBOUNDING INTO THE LOW 50S ONCE AGAIN...AFTER A COLD START TO THE DAY WITH LOWS IN THE LOW 20S. .LONG TERM...MONDAY NIGHT THROUGH NEXT THURSDAY. GFS AND EURO IN GOOD AGREEMENT MONDAY NIGHT THROUGH LATE TUESDAY NIGHT WITH INCREASING SOUTHWEST FLOW FROM APPROACHING LONG WAVE TROUGH OFFSHORE IN THE PACNW. AFTER THAT...THE GFS BECOMES SLIGHTLY DEEPER AND SLIGHTLY NEGATIVELY TILTED AND CLOSES OFF A LOW AND MOVES IT INTO THE INTERIOR PACIFIC NW...TRAILING A VORT LOBE OVER THE GREAT BASIN. THE EURO HOLD BACK THIS LOW WHILE CLOSING IT OFF BUT MORE SHALLOW...AND POSITIVELY TILTING THE TRAILING TROF. HENCE IT BRINGS IN THE COLD FRONT...HUMIDITY...AND PRECIP LATER. HAVE OPTED TO GOT WITH THE FASTER GFS. THE DRY SOUTHWEST FLOW WILL KEEP THINGS DRY THROUGH WEDNESDAY MORNING WHEN A LITTLE SHORT WAVE WILL CROSS NORTHERN NEVADA AND PROVIDE VERY LOW CHANCE POPS ALONG THE IDAHO BORDER WITH SLIGHT CHANCE POPS IN NORTHERN NEVADA WITH BARELY DOUBLE DIGIT POPS IN CENTRAL AND EASTERN NEVADA. DRY SOUTH TO SOUTHWEST WINDS WILL INCREASE IN SPEED IN ADVANCE OF THE WAVE APPROACHING TUESDAY NIGHT/WEDNESDAY MORNING. TEMPS SHOULD BE COOLER THAN OUR CURRENT ABOVE NORMAL PATTERN. MINS WILL BE LOWER WITH FEWER CLOUDS AND LIGHTER WINDS. AS CLOSED GFS LOW MOVES NORTH OF THE GREAT BASIN EXPECTING TRAILING LOW LEVEL TROUGH TO CROSS THE STATE AND INCREASE SOUTH-SOUTHWEST WINDS IN ADVANCE. MIGHT POSSIBLY MEET ADVISORY CRITERIA LATE WEDNESDAY AND EARLY THURSDAY. POPS...TEMPS...REMAIN CONSTANT DURING THE WED-THURSDAY FRAME. && .AVIATION...A PACIFIC FRONT IS APPROACHING THE NORTHERN GREAT BASIN AND WINDS AND CLOUDS WILL INCREASE OVER NIGHT AND ESPECIALLY ON SATURDAY. ISOLATED SHOWERS WILL OCCUR NEAR KWMC AND KEKO ON SATURDAY. CIGS AND VSBYS WILL BE TECHNICALLY VFR AT ALL SITES BUT MOUNTAIN TOPS WILL BE POTENTIALLY OBSCURED AT ALL SITES. WINDS WILL INCREASE TO OVER 35 KNOTS AT ALL SITES SATURDAY AFTERNOON WITH OVER 45 KNOTS AT KEKO...AND OVER 50 KNOTS AT KELY AND KTPH. && .FIRE WEATHER...AN INTENSE COLD FRONT WILL ENTER THE FIRE DISTRICT SATURDAY AFTERNOON AND EXIT EARLY SUNDAY MORNING. MIN RH WILL GENERALLY BE AROUND 15% AND WIND GUSTS COULD REACH TO AROUND 70 MPH AS THE FRONT MOVES THROUGH SATURDAY AFTERNOON AND EVENING. FUELS CONTINUE TO APPEAR NON-CRITICAL. AFTER COLLABORATION WITH SPC...WILL HAVE A SEE-TEXT BOX FOR NORTHERN NYE COUNTY. FIRE MANAGERS ARE URGED TO USE EXTREME CAUTION AND REFRAIN FROM ALL BURNING SATURDAY AFTERNOON AND EVENING. && .LKN WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 11 AM TO 11 PM PDT SATURDAY FOR EXTREME EASTERN ELKO COUNTY...NORTHERN ELKO COUNTY...NORTHERN LANDER COUNTY AND NORTHERN EUREKA COUNTY...NORTHERN NYE COUNTY...RUBY MOUNTAINS/EAST HUMBOLDT RANGE...SOUTHERN LANDER COUNTY AND SOUTHERN EUREKA COUNTY...SOUTHWEST AND SOUTH CENTRAL ELKO COUNTY...WHITE PINE COUNTY. HIGH WIND WARNING FROM 8 AM TO 11 PM PDT SATURDAY FOR HUMBOLDT COUNTY. WIND ADVISORY UNTIL 7 PM PDT THIS EVENING FOR HUMBOLDT COUNTY. && $$ 95/98/98/99
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1035 PM EDT SAT MAR 31 2012 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL IMPACT THE AREA THROUGH TONIGHT AS A COLD FRONT CROSSES THE AREA ...AND THEN MOVES OFF THE COAST. DRY WEATHER IS EXPECTED SUNDAY AS HIGH PRESSURE PASSES ACROSS THE REGION. A WEAK COLD FRONT WILL DROP SOUTH THROUGH THE AREA MONDAY. UNSETTLED CONDITIONS WILL RETURN BY THE MIDDLE OF NEXT WEEK AS A LOW PRESSURE SYSTEM APPROACHES THE EASTERN CAROLINAS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 1030 PM SATURDAY...LATEST SFC ANALYSIS PLACES THE COLD FRONT PARTIALLY INTO NC...DROPPING FROM THE NORTH. THE CONVECTION ACROSS THE NE PORTION OF THE STATE IS BASICALLY ALONG THE COLD FRONT ITSELF. THE OUTFLOW FROM THIS CONVECTION IS AIDING THE COLD FRONTS PUSH SOUTHWARD...AND COULD REACH THE NORTHERN PORTIONS OF THE ILM CWA BY MIDNIGHT THROUGH 1 AM SUNDAY. SLIGHTLY FASTER THAN 1ST PROGGED WITH HRRR AND AN EARLIER NAM MODEL RUN. HRRR INDICATES 1 MORE POTENTIAL MINI ROUND OF CONVECTION TO PUSH THROUGH IMMEDIATELY AHEAD OF THE COLD FRONT. WILL CONTINUE WITH LOW CHANCE POPS THROUGH ROUGHLY 2 AM SUNDAY. LOOKING AT NAM 1K-8H PARTIAL THICKNESS PACKING AND HRRR HRLY WINDS...THE COLD FRONT WILL DROP NEARLY DUE SOUTH ACROSS THE FA BETWEEN 1AM AND 7AM SUNDAY. LOOK FOR NW WINDS TO VEER TO THE N-NE ALONG WITH A MINI CAA SURGE THAT WILL ONLY LAST THRU MIDDAY SUNDAY B4 SHUTTING OFF. WITH THREAT OF PCPN INTO THE EARLY AM HRS OF SUNDAY AND CLOUDS STICKING AROUND FOR MUCH OF THE REMAINDER OF THE NIGHT. HAVE KEPT FOG DEVELOPMENT AT A MINIMUM WITH AN INCREASED POTENTIAL FOR A BRIEF STRATUS DECK UP THRU 1-2 HRS AFTER DAYBREAK. HAVE KEPT OVERNIGHT LOWS STABLE AFTER INCREASING A DEGREE OR 3 EARLIER...ESPECIALLY THE SOUTHERNMOST LOCALES WHERE THE FROPA WILL COINCIDE WITH DAYBREAK. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 300 PM SATURDAY...COLD FRONT POSITIONED JUST OFFSHORE AT THE START OF THE PERIOD. NVA AND SOME DRY AIR ADVECTION THROUGH THE MID LEVELS OF THE COLUMN KEEP SUNDAY SUNNY...BUT TEMPS WILL WARM WELL INTO THE 70S WITH LACK OF ANY CAA AND ENHANCED RIDGING ALOFT. TEMPS REMAIN WELL ABOVE CLIMO SUNDAY NIGHT AS GRADIENT TIGHTENS BETWEEN RIDGE OF HIGH PRESSURE AND ADVANCING COLD FRONT FROM THE NORTH. THIS COMBINED WITH SOME INCREASING MID-LEVEL CLOUDINESS WILL KEEPS MINS IN THE MID/UPPER 50S. SHORTWAVE TROUGH ROTATING DOWN FROM NEW ENGLAND SPAWNS A SURFACE LOW IN THE MID ATLANTIC WHICH TRIES TO DRIVE A COLD FRONT THROUGH EARLY MONDAY. WITH N/NW FLOW ALOFT...ANTICIPATE THIS FRONT TO WORK ALL THE WAY SOUTH THROUGH THE CWA BY AFTN. DURING FROPA...MID LEVEL LAPSE RATES STEEPEN AND FORECAST SOUNDINGS DEPICT INCREASING SATURATION IN THE 800-500MB LAYER. FORCING IS NOT STRONG...BUT WILL ADD A SCHC POP FOR TSTMS MONDAY...DECREASING FROM NORTH TO SOUTH THROUGH THE AFTN. THIS FRONT WILL MAKE FOR A DIFFICULT TEMP FORECAST MONDAY AS WELL...WITH 850MB TEMPS POSSIBLY FALLING THROUGH PEAK HEATING...ESPECIALLY ACROSS NE ZONES. EXPECT TEMPS TO RANGE FROM THE UPPER 80S IN THE TYPICAL WARM PEE DEE LOCATIONS...TO AROUND 80 IN THE NORTHEAST ZONES...EVEN WITH FAVORED DOWNSLOPE COMPRESSIONAL WARMING OCCURRING. FRONT STALLS SOUTH OF THE AREA AND SOME ISENTROPIC LIFT BEGINS LATE MONDAY NIGHT...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE CWA. WILL RAMP POP BACK UP TO SCHC ACROSS THE SOUTH. MINS WILL FALL TO AROUND 50 ACROSS THE NORTHEAST CWA...TO NEAR 60 IN THE SOUTH. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 300 PM SATURDAY...AMPLITUDE WILL ONCE AGAIN BE THE NAME OF THE GAME FOR THE EXTENDED AS A LARGE MID LEVEL CYCLONE WILL BE WOBBLING OVER THE FOUR CORNERS REGION INITIALLY WITH RIDGING JUST WEST OF OUR REGION. AT THE SURFACE A FRONT WILL RESIDE JUST TO THE SOUTHWEST BEFORE GETTING WASHED OUT WEDNESDAY. A BACKDOOR FRONT WILL MOVE ACROSS THURSDAY INCREASING THE WEAK FORCING MECHANISMS IN PLACE...THIS AS THE MID LEVEL PATTERN AMPLIFIES SLIGHTLY. FINALLY LATE THURSDAY AND FRIDAY THE MAIN SYSTEM ASSOCIATED WITH THE PREVIOUSLY MENTIONED MID LEVEL LOW MOVES ACROSS. BOTTOM LINE...I HAVE INCREASED POPS FROM TUESDAY THROUGH THURSDAY INCREMENTALLY BASED ON A DIURNAL SCENARIO. THE NEW DAY...SATURDAY LOOKS DRY AT THIS POINT BUT THE INHERIT DIFFICULTIES OF FORECASTING A CLOSED SYSTEM THIS FAR OUT IN TIME MAKE FOR A LOW CONFIDENCE DRY FORECAST. REGARDING TEMPERATURES...HAVE INCREASED TEMPERATURES A BIT ACROSS THE BOARD TO MATCH GUIDANCE AND ADJACENT OFFICES BUT OVERALL TRENDS OF SLIGHTLY ABOVE EARLY TREND TO NEAR NORMAL LATE REMAIN INTACT. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 00Z...LINGERING CONVECTION WILL AFFECT MYR FOR THE FIRST HOUR OR SO...THEN MOVE OFFSHORE WITH THE PRE FRONTAL TROUGH. AFTER 03Z...A SECONDARY BATCH OF CONVECTION IS POSSIBLE WITH THE ACTUAL FRONT. THIS PRECIP WILL BE WANING AS IS COMES OVER THE MOUNTAINS...AND IT SHOULD NOT BE MUCH OF A FACTOR. TOWARD MORNING...WINDS WILL SHIFT TO THE NORTHEAST...AND AN IFR CEILING IS POSSIBLE BUT CONFIDENCE IS FAIRLY LOW. LOOK FOR A COMBINATION OF CEILING AND VISIBILITY PROBLEMS AROUND SUNRISE...BECOMING VFR AT ALL TERMINALS BY 13-14Z. WINDS WILL CONTINUE TO VEER TO THE EAST NORTHEAST...THEN SOUTHEAST ALONG THE COAST IN THE AFTERNOON WITH THE RESULTANT. EXTENDED OUTLOOK...LOW CONFIDENCE SHOWERS/ISOLATED THUNDERSTORM MONDAY AND TUESDAY. SCATTERED CONVECTION POSSIBLE WEDNESDAY WITH A BETTER CHANCE FOR PRECIP ON THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...LATEST OBSERVATIONS OVER THE ILM NC WATERS INDICATE SEAS STILL RUNNING WITHIN SCA THRESHOLDS ACROSS THE OUTER WATERS OFF CAPE FEAR. THE SCA WILL REMAIN THRU MIDNIGHT WHICH IS AMPLE TIME FOR THESE SEAS TO SUBSIDE BELOW SCA THRESHOLDS. GUIDANCE CONTINUES TO FURTHER SUBSIDE SEAS DURING THE PRE-DAWN HRS OF SUNDAY AS A COLD FRONT DROPS SOUTH ACROSS THE ILM WATERS BETWEEN 1 AM AND 7 AM SUNDAY. WINDS WILL VEER TO THE N-NE AFTER FROPA AND AID IN KNOCKING DOWN THE BUILT UP SHORT PERIOD SW WIND DRIVEN SEAS FROM THE PAST 1-2 DAYS. COULD SEE THE LAST ROUND OF CONVECTION MOVE OFF THE MAINLAND THROUGH 2 AM SUNDAY. OTHERWISE...LOOK FOR A N-NE MINI SHORT LIVED COLD SURGE BEHIND THE COLD FRONT...LASTING THROUGH MID TO LATE SUNDAY MORNING. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 PM SATURDAY...COLD FRONT WILL BE POSITIONED OFFSHORE AT THE START OF THE PERIOD WITH N/NE WINDS ONGOING ACROSS THE WATERS. RIDGE OF HIGH PRESSURE BUILDS IN FROM THE SOUTH DURING THE AFTN AND WINDS BECOME LIGHT...VEERING TO THE SW THROUGH THE EVE AS A PRE FRONTAL AIRMASS MOVES OVER THE AREA AND INCREASING RAPIDLY TO 15-20 KTS SUN NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. COLD FRONT DROPS SOUTH DURING MONDAY...AND WINDS WILL GRADUALLY VEER FROM SW TO N...THEN NE MONDAY NIGHT...ALL AT SPEEDS OF AROUND 10 KTS. LACK OF ANY MEANINGFUL SWELL WITHIN THE WAVE SPECTRUM MEANS THAT SEAS WILL BE PRIMARILY WIND DRIVEN...2-3 FT THROUGH THE PERIOD...WITH A COMBINATION OF NE AND SW CHOP SUNDAY...BECOMING DOMINATED BY NE WAVE ON MONDAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 PM SATURDAY...MAIN EVENT FOR THE MARINE COMMUNITY WILL BE THE BACK DOOR FRONT MOVING ACROSS THURSDAY. THIS FRONT WILL EVENTUALLY BRING ALL WINDS AROUND TO NORTHEAST BUT FOR MOST OF THE DAY THURSDAY THE NORTH CAROLINA AND SOUTH CAROLINA WATERS WILL BE DIVIDED BY THE FRONT. FOR EARLIER IN THE PERIOD...EASTERLY WINDS INITIALLY WITH A SOUTH TO SOUTHWESTERLY FLOW DEVELOPING LATER TUESDAY AND PREVAILING THROUGH WEDNESDAY. SEAS ARE GENERALLY 2-4 FEET WITH WINDS WAVES DOMINATING THE SPECTRUM. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ250-252. && $$ NEAR TERM...DCH SHORT TERM...JDW LONG TERM...SHK AVIATION...HDL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
745 PM EDT SAT MAR 31 2012 .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL IMPACT THE AREA THROUGH TONIGHT AS A COLD FRONT CROSSES THE AREA ...AND THEN MOVES OFF THE COAST. DRY WEATHER IS EXPECTED SUNDAY AS HIGH PRESSURE PASSES ACROSS THE REGION. A WEAK COLD FRONT WILL DROP SOUTH THROUGH THE AREA MONDAY. UNSETTLED CONDITIONS WILL RETURN BY THE MIDDLE OF NEXT WEEK AS A LOW PRESSURE SYSTEM APPROACHES THE EASTERN CAROLINAS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 735 PM SATURDAY...LATEST SFC ANALYSIS PLACES THE COLD FRONT GENERALLY FROM THE NC-VA BORDER AT THE COAST...WESTWARD TO ROUGHLY ASHEVILLE. HRRR INDICATES 1 MORE MINI ROUND OF CONVECTION TO PUSH THROUGH IMMEDIATELY AHEAD OF THE COLD FRONT BETWEEN 02Z-06Z. HAVE INDICATED LOW CHANCE POPS THROUGH MIDNIGHT PRIOR TO THE CFP. LOOKING AT NAM 1K-8H THICKNESS PACKING AND HRRR HRLY WINDS...THE COLD FRONT WILL DROP NEARLY DUE SOUTH ACROSS THE FA BETWEEN 2AM AND 7AM SUNDAY. LOOK FOR NW WINDS TO VEER TO THE N-NE ALONG WITH A MINI CAA SURGE THAT WILL ONLY LAST THRU MIDDAY SUNDAY B4 SHUTTING OFF. WITH THREAT OF PCPN INTO THE EARLY AM HRS OF SUNDAY AND CLOUDS STICKING AROUND FOR MUCH OF THE NIGHT...HAVE KEPT FOG DEVELOPMENT AT A MINIMUM. IN ADDITION...HAVE INCREASED OVERNIGHT LOWS A FEW DEGREES ESPECIALLY THE SOUTHERNMOST LOCALES WHERE THE FROPA WILL COINCIDE WITH DAYBREAK. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 300 PM SATURDAY...COLD FRONT POSITIONED JUST OFFSHORE AT THE START OF THE PERIOD. NVA AND SOME DRY AIR ADVECTION THROUGH THE MID LEVELS OF THE COLUMN KEEP SUNDAY SUNNY...BUT TEMPS WILL WARM WELL INTO THE 70S WITH LACK OF ANY CAA AND ENHANCED RIDGING ALOFT. TEMPS REMAIN WELL ABOVE CLIMO SUNDAY NIGHT AS GRADIENT TIGHTENS BETWEEN RIDGE OF HIGH PRESSURE AND ADVANCING COLD FRONT FROM THE NORTH. THIS COMBINED WITH SOME INCREASING MID-LEVEL CLOUDINESS WILL KEEPS MINS IN THE MID/UPPER 50S. SHORTWAVE TROUGH ROTATING DOWN FROM NEW ENGLAND SPAWNS A SURFACE LOW IN THE MID ATLANTIC WHICH TRIES TO DRIVE A COLD FRONT THROUGH EARLY MONDAY. WITH N/NW FLOW ALOFT...ANTICIPATE THIS FRONT TO WORK ALL THE WAY SOUTH THROUGH THE CWA BY AFTN. DURING FROPA...MID LEVEL LAPSE RATES STEEPEN AND FORECAST SOUNDINGS DEPICT INCREASING SATURATION IN THE 800-500MB LAYER. FORCING IS NOT STRONG...BUT WILL ADD A SCHC POP FOR TSTMS MONDAY...DECREASING FROM NORTH TO SOUTH THROUGH THE AFTN. THIS FRONT WILL MAKE FOR A DIFFICULT TEMP FORECAST MONDAY AS WELL...WITH 850MB TEMPS POSSIBLY FALLING THROUGH PEAK HEATING...ESPECIALLY ACROSS NE ZONES. EXPECT TEMPS TO RANGE FROM THE UPPER 80S IN THE TYPICAL WARM PEE DEE LOCATIONS...TO AROUND 80 IN THE NORTHEAST ZONES...EVEN WITH FAVORED DOWNSLOPE COMPRESSIONAL WARMING OCCURRING. FRONT STALLS SOUTH OF THE AREA AND SOME ISENTROPIC LIFT BEGINS LATE MONDAY NIGHT...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE CWA. WILL RAMP POP BACK UP TO SCHC ACROSS THE SOUTH. MINS WILL FALL TO AROUND 50 ACROSS THE NORTHEAST CWA...TO NEAR 60 IN THE SOUTH. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 300 PM SATURDAY...AMPLITUDE WILL ONCE AGAIN BE THE NAME OF THE GAME FOR THE EXTENDED AS A LARGE MID LEVEL CYCLONE WILL BE WOBBLING OVER THE FOUR CORNERS REGION INITIALLY WITH RIDGING JUST WEST OF OUR REGION. AT THE SURFACE A FRONT WILL RESIDE JUST TO THE SOUTHWEST BEFORE GETTING WASHED OUT WEDNESDAY. A BACKDOOR FRONT WILL MOVE ACROSS THURSDAY INCREASING THE WEAK FORCING MECHANISMS IN PLACE...THIS AS THE MID LEVEL PATTERN AMPLIFIES SLIGHTLY. FINALLY LATE THURSDAY AND FRIDAY THE MAIN SYSTEM ASSOCIATED WITH THE PREVIOUSLY MENTIONED MID LEVEL LOW MOVES ACROSS. BOTTOM LINE...I HAVE INCREASED POPS FROM TUESDAY THROUGH THURSDAY INCREMENTALLY BASED ON A DIURNAL SCENARIO. THE NEW DAY...SATURDAY LOOKS DRY AT THIS POINT BUT THE INHERIT DIFFICULTIES OF FORECASTING A CLOSED SYSTEM THIS FAR OUT IN TIME MAKE FOR A LOW CONFIDENCE DRY FORECAST. REGARDING TEMPERATURES...HAVE INCREASED TEMPERATURES A BIT ACROSS THE BOARD TO MATCH GUIDANCE AND ADJACENT OFFICES BUT OVERALL TRENDS OF SLIGHTLY ABOVE EARLY TREND TO NEAR NORMAL LATE REMAIN INTACT. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 00Z...LINGERING CONVECTION WILL AFFECT MYR FOR THE FIRST HOUR OR SO...THEN MOVE OFFSHORE WITH THE PRE FRONTAL TROUGH. AFTER 03Z...A SECONDARY BATCH OF CONVECTION IS POSSIBLE WITH THE ACTUAL FRONT. THIS PRECIP WILL BE WANING AS IS COMES OVER THE MOUNTAINS...AND IT SHOULD NOT BE MUCH OF A FACTOR. TOWARD MORNING...WINDS WILL SHIFT TO THE NORTHEAST...AND AN IFR CEILING IS POSSIBLE BUT CONFIDENCE IS FAIRLY LOW. LOOK FOR A COMBINATION OF CEILING AND VISIBILITY PROBLEMS AROUND SUNRISE...BECOMING VFR AT ALL TERMINALS BY 13-14Z. WINDS WILL CONTINUE TO VEER TO THE EAST NORTHEAST...THEN SOUTHEAST ALONG THE COAST IN THE AFTERNOON WITH THE RESULTANT. EXTENDED OUTLOOK...LOW CONFIDENCE SHOWERS/ISOLATED THUNDERSTORM MONDAY AND TUESDAY. SCATTERED CONVECTION POSSIBLE WEDNESDAY WITH A BETTER CHANCE FOR PRECIP ON THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 735 PM SATURDAY...LATEST OBSERVATIONS OVER THE ILM NC WATERS INDICATE SEAS STILL RUNNING WITHIN SCA THRESHOLDS ACROSS THE OUTER WATERS OFF CAPE FEAR. WILL EXTEND THE SCA THRU MIDNIGHT ALLOWING THE SEAS TO SUBSIDE BELOW SCA THRESHOLDS. GUIDANCE CONTINUES TO FURTHER SUBSIDE SEAS DURING THE PRE-DAWN HRS OF SUNDAY AS A COLD FRONT DROPS SOUTH ACROSS THE ILM WATERS BETWEEN 1 AM AND 7 AM SUNDAY. WINDS WILL VEER TO THE N-NE AFTER FROPA AND AID IN KNOCKING DOWN THE BUILT UP SHORT PERIOD SW WIND DRIVEN SEAS FROM THE PAST 1-2 DAYS. COULD SEE A ROUND OF CONVECTION MOVE OFF THE MAINLAND IMMEDIATELY PRIOR TO THE CFP. OTHERWISE...LOOK FOR A N-NE MINI SHORT LIVED COLD SURGE BEHIND THE FRONT THROUGH MID TO LATE SUNDAY MORNING. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 PM SATURDAY...COLD FRONT WILL BE POSITIONED OFFSHORE AT THE START OF THE PERIOD WITH N/NE WINDS ONGOING ACROSS THE WATERS. RIDGE OF HIGH PRESSURE BUILDS IN FROM THE SOUTH DURING THE AFTN AND WINDS BECOME LIGHT...VEERING TO THE SW THROUGH THE EVE AS A PRE FRONTAL AIRMASS MOVES OVER THE AREA AND INCREASING RAPIDLY TO 15-20 KTS SUN NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. COLD FRONT DROPS SOUTH DURING MONDAY...AND WINDS WILL GRADUALLY VEER FROM SW TO N...THEN NE MONDAY NIGHT...ALL AT SPEEDS OF AROUND 10 KTS. LACK OF ANY MEANINGFUL SWELL WITHIN THE WAVE SPECTRUM MEANS THAT SEAS WILL BE PRIMARILY WIND DRIVEN...2-3 FT THROUGH THE PERIOD...WITH A COMBINATION OF NE AND SW CHOP SUNDAY...BECOMING DOMINATED BY NE WAVE ON MONDAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 PM SATURDAY...MAIN EVENT FOR THE MARINE COMMUNITY WILL BE THE BACK DOOR FRONT MOVING ACROSS THURSDAY. THIS FRONT WILL EVENTUALLY BRING ALL WINDS AROUND TO NORTHEAST BUT FOR MOST OF THE DAY THURSDAY THE NORTH CAROLINA AND SOUTH CAROLINA WATERS WILL BE DIVIDED BY THE FRONT. FOR EARLIER IN THE PERIOD...EASTERLY WINDS INITIALLY WITH A SOUTH TO SOUTHWESTERLY FLOW DEVELOPING LATER TUESDAY AND PREVAILING THROUGH WEDNESDAY. SEAS ARE GENERALLY 2-4 FEET WITH WINDS WAVES DOMINATING THE SPECTRUM. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ250-252. && $$ NEAR TERM...DCH SHORT TERM...JDW LONG TERM...SHK AVIATION...HDL
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
845 PM CDT SAT MAR 31 2012 .DISCUSSION... CHALLENGES FOR TONIGHT INCLUDE TEMPERATURES AND FOG POTENTIAL. WILL LEAN ON HIGH RESOLUTION RUC/HRRR GUIDANCE FOR EVENING UPDATE. CLEAR SKIES WILL GIVE WAY TO INCREASING MID-HIGH LEVEL CLOUDS ALONG STRENGTHENING MID-LEVEL BAROCLINIC ZONE. THERE ARE SOME RADAR ECHOES ACROSS NORTHEAST MT AND NORTHWEST ND...BUT VERY LITTLE LIQUID IS REACHING THE GROUND. WILL MAINTAIN SLIGHT CHANCE POPS AFTER MIDNIGHT ACROSS PORTIONS OF THE DEVILS LAKE BASIN AND NORTHERN VALLEY...BUT DO NOT ANTICIPATE MUCH ACCUMULATION IF ANY. INCREASING WARM AIR ADVECTION FROM THE WEST WILL KEEP NIGHTTIME LOWS ELEVATED INTO THE MID TO UPPER 40S ACROSS EASTERN ND WITH SLIGHTLY COOLER CONDITIONS EAST OF THE RIVER GIVEN LOWER DAYTIME HIGHS AND CLEAR SKIES EARLY THIS EVENING. BIG QUESTION FOR TONIGHT IS FOG. LATEST HRRR SHOWS VISIBILITY DROPPING TO LESS THAN ONE HALF MILE ACROSS A LARGE SWATH OF NORTH- CENTRAL AND NORTHWEST MN AFTER 03 UTC. THIS MAKES SENSE GIVEN HIGH SURFACE DEW POINTS...LIGHT WIND AND CLEAR SKIES THIS EVENING. DO NOT THINK LOW STRATUS DECK ACROSS EASTERN MN WILL RETROGRADE TO THE WEST TOO FAR GIVEN WEAK SURFACE FLOW...BUT AREAS OF FOG ARE POSSIBLE. ADDED AREAS OF FOG EAST OF THE VALLEY FROM 06 TO 15 UTC THIS MORNING. WILL MONITOR THE LATEST CONDITIONS AND UPDATE THE FORECAST AS NEEDED. && .AVIATION... CLEAR SKIES WILL GIVE WAY TO SOME INCREASING MID-HIGH LEVEL CLOUDS OVERNIGHT. BIGGER CONCERN IS FOG POTENTIAL ALONG AND EAST OF THE VALLEY GIVEN HIGH LOW-LEVEL MOISTURE AND LIGHT WIND. COVERAGE AND TIMING UNCERTAINTY EXISTS...SO WILL WAIT TO ADD MENTION AND UPDATE AS NECESSARY. && .PREV DISCUSSION... /ISSUED 230 PM CDT SAT MAR 31 2012/ DISCUSSION...FORECAST CHALLENGE CONCERNS SHORT TERM RAIN CHANCES AND TEMPERATURES. MAIN MODEL DIFFERENCES ARE TIMING OF BOUNDARY PASSAGE LATER SUNDAY. GFS/GEM A COMPROMISE BETWEEN QUICKER NAM AND SLOWER ECMWF SO WILL USE GFS FOR TIMING PURPOSES. WEAK SURFACE BOUNDARY SHOULD CONTINUE TO PUSH EAST REMAINDER OF AFTERNOON FOLLOWED BY SURFACE HIGH PRESSURE. RIDGE AXIS SHIFTS OVER EASTERN FA TOWARDS MORNING AND WITH EXPECTED SKC COULD SEE SOME PATCHY FOG. ELSEWHERE EASTERLY FLOW AHEAD OF NEXT SYSTEM SHOULD INCREASE ENOUGH TO LIMIT FOG ELSEWHERE. WILL SEE A N-S LOW LEVEL MOISTURE GRADIENT SO WARMEST TEMPERATURES EXPECTED ACROSS THE SOUTH. WILL MAINTAIN LOW POPS ACROSS FAR N-W AS DEEPER LAYERED RH INCREASES SOME ALONG WITH SOME MID LEVEL FRONTOGENETIC FORCING. MID LEVEL RIDGE SHIFTS ACROSS FA ON SUNDAY. SURFACE BOUNDARY WILL SHIFT EAST BUT THINKING BOUNDARY WILL REMAIN WEST OF FA THROUGH THE AFTERNOON. THIS WILL KEEP FA IN WARM SECTOR AND IF CLOUDS ARE LIMITED COULD SEE SOME RECORD HIGHS FALL. WILL BE WINDY AND WILL NEED TO BE MONITORED FOR POTENTIAL ADVISORY HEADLINES. NORTHERN MN WILL HAVE SOME LOWER DEWPOINTS BUT TEMPERATURES WILL BE COOLER SO FEEL CONDITIONS WILL BE BLO ANY FIRE WEATHER CONCERNS. BOUNDARY CROSSES FA SUNDAY NIGHT. AIRMASS AHEAD OF THIS FEATURE PRIMARILY ACROSS MN BECOMES MODESTLY UNSTABLE WITH SOME ELEVATED CAPE SO WILL MAINTAIN LOW CHANCES FOR ELEVATED THUNDERSTORMS. MID LEVEL FLOW BECOMES SPLIT WITH NORTHERN STREAM WAVE TO AFFECT FA MONDAY. MODELS DIFFER ON TIMING OF BOUNDARY AND APPROACHING MID LEVEL SUPPORT. ECMWF SLOWER WITH PASSAGE OF INVERTED TROUGH AND SPREADING MORE PCPN ON COLD SIDE OF TROUGH SO WILL SPREAD POPS FARTHER WEST A BIT. HIGH PRESSURE TO BUILD IN FROM WEST TO EAST MONDAY NIGHT INTO TUESDAY. TUESDAY LOOKS DRY WITH ABOVE AVERAGE TEMPERATURES. LONG TERM...TUESDAY NIGHT THROUGH SATURDAY GFS/ECMWF/DGEX/GEM IN GOOD AGREEMENT THROUGH 00 UTC FRIDAY... DIVERGING SOMEWHAT THEREAFTER WITH NEXT EASTERN PACIFIC TROUGH. TUESDAY THROUGH MOST OF FRIDAY WILL BE QUITE PLEASANT AS AN UPPER LEVEL RIDGE AND SURFACE HIGH MOVE SLOWLY ACROSS THE NATION/S MIDSECTION. WITH THE EXCEPTION OF SOME LIGHT RAIN SHOWERS POSSIBLE WEST OF THE VALLEY LATE FRIDAY...CONDITIONS WILL BE DRY WITH HIGHS IN THE 60S AND LOWS IN THE 40S. THE SURFACE PRESSURE GRADIENT WILL STRENGTHEN THURSDAY AND FRIDAY AS THE SURFACE HIGH MOVES INTO THE GREAT LAKES...RESULTING IN BREEZY SOUTHERLY WIND EACH AFTERNOON. GFS AND ECMWF SHOW A SHORT-WAVE EJECTING NORTHEASTWARD FROM WESTERN CONUS TROUGH FRIDAY NIGHT ANS SATURDAY. PWATS AROUND AN INCH MAY RESULT IN SOME DECENT RAIN...BUT WITH LITTLE INSTABILITY...ONLY EXPECT SHOWERS AT THIS TIME. TEMPERATURES WILL COOL SATURDAY WITH HIGHS DROPPING INTO THE 50S. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ ROGERS/VOELKER
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1100 AM CDT FRI MAR 30 2012 .DISCUSSION... CHALLENGE THIS MORNING IS FOG...CLOUD TRENDS AND TEMPERATURES. DENSE FOG WITH VISIBILITY LESS THAN ONE QUARTER MILE HAS LIFTED ACROSS MUCH OF EASTERN ND...EXCEPT ACROSS THE FAR WESTERN FORECAST AREA FROM ROLLA TO DEVILS LAKE TO JAMESTOWN. AS PRESSURE GRADIENT STRENGTHENS...EXPECT SOUTHERLY SURFACE WINDS TO INCREASE AND SCOUR OUT REMAINING AREAS OF FOG. WILL ALLOW THE DENSE FOG ADVISORY TO EXPIRE AT 11 AM CDT AND COVER ANY LINGERING FOGGY AREAS WITH NOWCASTS. LOW STRATUS DECK ACROSS ALL AREAS EXCEPT SOUTHEAST ND WILL BE VERY SLOW TO DISSIPATE GIVEN WEAK FLOW ALOFT. RUC 925 HPA RH SEEMS TO HAVE A GOOD HANDLE ON CURRENT CONDITIONS AND SUGGESTS SOME CLEARING ALONG AND WEST OF THE VALLEY THIS AFTERNOON...BUT PERSISTENT OVERCAST CONDITIONS ACROSS NORTHWEST MN THROUGH AT LEAST 00 UTC TONIGHT. AS A RESULT...SIGNIFICANTLY INCREASED SKY COVER THROUGH THE DAY AND DROPPED TEMPERATURES 2-5 DEGREES. IF CLOUDS HANG TOUGH... STILL MAY BE TOO WARM WITH SOME AREAS EAST OF THE VALLEY NOT BREAKING THE 40 DEGREE MARK. WILL MAKE ADDITIONAL ADJUSTMENTS THIS AFTERNOON IF NEEDED. && .AVIATION... WHEREAS VISIBILITY WILL IMPROVE LATE THIS MORNING AND EARLY AFTERNOON AS FOG LIFTS AND DISSIPATES...IFR/MVFR STRATUS DECK WILL BE SLOW TO ERODE THROUGH THE DAY. DIFFICULT TO SAY EXACTLY WHEN CEILINGS WILL IMPROVE...SO WILL UPDATE TAFS AS NECESSARY. LIGHT AND VARIABLE WIND THIS MORNING WILL INCREASE AND SHIFT TO THE SOUTH THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 430 AM CDT FRI MAR 30 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT. UPPER LEVEL FLOW WAS ZONAL AND IS FORECAST TO BECOME A LITTLE MORE AMPLIFIED AFTER 48 HOURS. UPPER TROUGH OVER THE EASTERN PACIFIC WILL MOVE INTO THE WESTERN US SAT NIGHT AND WILL BEGIN TO AFFECT THE FORECAST AREA SUN NIGHT. UPPER LEVEL JET WILL BE NORTH OF THE FORECAST AREA SAT AND SUN. WATER VAPOR LOOP SHOWED A SHORT WAVE OVER SOUTHERN ALTA/BC THAT WILL MOVE ACROSS SOUTHERN MAN TONIGHT. MAY PRODUCE LIGHT SHOWERS OVER THE FAR NORTH AND NORTHEAST SAT MORNING. EAST WEST CROSS SECTION INDICATED DRY AIR WAS MOVING IN ALOFT WHILE THE BOUNDARY LAYER REMAINED MOIST. SURFACE OBS AND FOG LOOP INDICATED FOG WAS SPREADING SOUTH AND WEST OVER EASTERN ND WHILE A CLOUD DECK REMAINED STATIONARY OVER NORTHWEST AND WEST CENTRAL MN. WILL KEEP FOG ADVISORY GOING OVER EASTERN ND AS CLOUD DECK OVER MN DOES NOT APPEAR TO BE MOVING. LONG TERM [MONDAY-THURSDAY]... GFS AND GEM START OUT IN GOOD AGREEMENT ON MONDAY...WITH A SPLIT SYSTEM MOVING INTO THE PLAINS AND THE NORTHERN BRANCH SHORTWAVE INTO THE DAKOTAS. 12Z ECMWF WAS MORE PHASED WITH THE TROUGH...BUT THE 00Z RUN IS MORE IN LINE WITH THE OTHER DETERMINISTIC MODELS. ALL HAVE A TROUGH OF LOW PRESSURE MAINLY OVER THE EASTERN CWA WITH PRECIP. SHOWALTERS ARE NEGATIVE...SO WILL KEEP A THUNDER MENTION FOR THE EASTERN TIER MONDAY MORNING BEFORE MORE STABLE AIR MOVES IN WITH A COLD FRONT. PRECIP SHOULD BE MOSTLY RAIN ALTHOUGH WITH 850MB TEMPS DROPPING BELOW ZERO AS THE SYSTEM EXITS MONDAY NIGHT SOME SNOW MIXING IN OVER LAKE OF THE WOODS IS NOT OUT OF THE QUESTION. BY TUESDAY AND THROUGH THE REST OF THE WORK WEEK...ALL OF THE MEDIUM RANGE MODELS ARE IN PRETTY GOOD AGREEMENT FOR WARMER AND DRIER CONDITIONS AS UPPER RIDGING AMPLIFIES OVER THE NORTHERN PLAINS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ ROGERS/HOPPES
AREA FORECAST DISCUSSION...CORRECTED
NWS BISMARCK ND
422 AM CDT FRI MAR 30 2012 .SHORT TERM...TODAY THROUGH SATURDAY... THE HIGHLIGHTS OF THE SHORT TERM WILL BE FOG AND FIRE WEATHER FOR TODAY...FOLLOWED BY NEAR RECORD HIGHS ON SATURDAY FOR THE SOUTHERN HALF OF THE CWA. AS DEPICTED BY HRRR FORECAST CYCLES THROUGHOUT THE EARLY MORNING HOURS...WIDESPREAD DENSE FOG HAS PUSHED TOWARDS NORTH DAKOTA HIGHWAY 14 THROUGH THE NIGHT WITH WEAK EASTERLY SURFACE FLOW ON THE EASTERN SIDE OF A QUASI-STATIONARY FRONT. THE DENSE FOG ADVISORY ISSUED EARLIER TONIGHT REMAINS IN EFFECT THROUGH 17 UTC THIS MORNING FOR LOCATIONS GENERALLY ALONG AND EAST OF HIGHWAY 14...WITH PATCHY FOG POSSIBLY ALONG THE HIGHWAY 83 CORRIDOR. FOR THE REMAINDER OF TODAY THE FOCUS WILL BE ON CRITICAL FIRE WEATHER CONDITIONS ACROSS FAR WESTERN NORTH DAKOTA...IN GENERAL ALONG AND WEST OF NORTH DAKOTA HIGHWAY 8. THE 30/00 UTC GFS AND ITS ASSOCIATED STATISTICAL GUIDANCE HAVE TRENDED TOWARDS THE WEAKER WINDS OF THE NAM. HOWEVER...WITH ADIABATIC LAPSE RATES FORECAST THROUGH 700 MB BY LATE AFTERNOON...EXCELLENT MOMENT EM TRANSFER IS FORECAST TO YIELD SUSTAINED WINDS OF 15-20 KTS WITH GUST TO NEAR 25 KTS...AND AFTERNOON MINIMUM RELATIVE HUMIDITY VALUES NEAR 20 PERCENT WITH TEMPERATURES IN THE LOWER 70S. GIVEN THE ABUNDANCE OF DRY FUELS AND LITTLE GREEN UP...HAVE UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG WARNING FROM 18-02 UTC. FOR TONIGHT...THE AFOREMENTIONED STATIONARY FRONT IS FORECAST TO SHIFT EAST AS A WARM FRONT AS A CLIPPER SYSTEM PROPAGATES ACROSS SOUTHERN CANADA...WITH A COLD FRONT ENTERING THE FAR NORTHWEST LATE TONIGHT. GIVEN THE RELATIVELY MILD TEMPERATURES FORECAST TODAY AND BOUNDARY LAYER MIXING THROUGH THE NIGHT WITH THE PASSAGE OF THE CLIPPER TO THE NORTH...A RELATIVELY MILD OVERNIGHT IS FORECAST WITH LOWS GENERALLY IN THE 40S. THE AFOREMENTIONED COLD FRONT IS FORECAST TO STALL OUT BETWEEN THE US HIGHWAY 2 AND ND HIGHWAY 200 CORRIDORS ON SATURDAY MORNING AND SLOWLY LIFT NORTH THROUGH THE DAY AS A WARM FRONT. RECORD HIGH TEMPERATURES ARE POSSIBLE SOUTH OF THE FRONT ON SATURDAY. SHOWN BELOW ARE THE FORECAST AND RECORD HIGHS FOR SELECT LOCATIONS ACROSS THE CWA. SITE FORECAST RECORD YEAR DICKINSON 76 75 1964 MINOT 70 68 1963 BISMARCK 74 75 2003 JAMESTOWN 71 77 1963 THESE FORECAST HIGHS ARE COOLER COMPARED TO PREVIOUS FORECASTS...LARGELY DUE LOWER MAGNITUDES OF FORECAST MIXING...WHICH HOWEVER WILL HELP TO KEEP FIRE WEATHER CONDITIONS FROM REACHING CRITICAL LEVELS. .LONG TERM...SATURDAY NIGHT THROUGH THURSDAY... THE MEDIUM RANGE MODELS CONTINUE TO TREND DRIER AND DRIER WITH RESPECT TO THE NEXT LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE REGION THIS WEEKEND. THE ECMWF/GFS/GEM ARE IN FAIRLY GOOD AGREEMENT WITH THE OVERALL DRY/WARM WEATHER PATTERN OVER NORTH DAKOTA NEXT WEEK. AS A RESULT...DECIDED TO USE A BLEND OF SOLUTIONS FOR THIS FORECAST PACKAGE. SURFACE CYCLOGENESIS IS FORECAST TO DEVELOP ACROSS THE CANADIAN ROCKIES SATURDAY NIGHT. A STRENGTHENING LOW-LEVEL JET COMBINED WITH INCREASING DYNAMICS ALOFT SHOULD GENERATE A SLIGHT CHANCE OF SHOWERS NORTH (PROXIMATE TO THE STRONGEST UPPER DYNAMICS) SATURDAY NIGHT. THE SHOWALTER INDEX INDICATES THERE WILL BE A POTENTIAL FOR THUNDERSTORM ACTIVITY NORTHWEST FROM 00Z-06Z...THEN MID-LEVEL LAPSE RATES BECOME RELATIVELY MORE STABLE AFTER 06Z PRECLUDING ANY THUNDERSTORM DEVELOPMENT AFTER MIDNIGHT SATURDAY NIGHT. THE SLIGHT CHANCES FOR SHOWERS WILL CONTINUE NORTH (AGAIN...PROXIMATE TO THE STRONGEST FORCING) SUNDAY AS THE LOW LIFTS INTO NORTHERN SASKATCHEWAN AND PUSHES A FRONT THROUGH NORTH DAKOTA. WINDY CONDITIONS WILL DEVELOP IN THE WAKE OF THE FRONT WEST AND CENTRAL. HUMIDITIES WILL ALSO PLUMMET WITH A VERY HIGH FIRE DANGER EXPECTED SOUTHWEST OF THE MISSOURI RIVER SUNDAY AFTERNOON. HIGH PRESSURE BUILDING INTO THE STATE WILL MAINTAIN BREEZY TO WINDY CONDITIONS ACROSS WESTERN AND CENTRAL NORTH DAKOTA SUNDAY NIGHT AND MONDAY. THE COMBINATION OF WINDS AND DRY CONDITIONS WILL GENERATE A VERY HIGH FIRE DANGER MAINLY ALONG AND SOUTH OF HIGHWAY 2 MONDAY AFTERNOON. AN AMPLIFYING UPPER LEVEL RIDGE IS FORECAST TO BUILD OVER THE CENTRAL GREAT PLAINS TUESDAY THROUGH THURSDAY. DRY CONDITIONS AND A WARMING TREND ARE EXPECTED THROUGH THE END OF THE FORECAST PERIOD. && .AVIATION...LIGHT WINDS AND A STABLE/MOIST BOUNDARY LAYER WILL MAINTAIN LIFR CONDITIONS IN DENSE FOG ACROSS KJMS THROUGH THE MID TO LATE MORNING HOURS. MVFR VSBYS WILL BE POSSIBLE FROM KMOT-KBIS THROUGH THE EARLY MORNING HOURS. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST DURING THE MORNING HOURS WITH VFR CONDITIONS EXPECTED AREA WIDE BY THIS AFTERNOON. LINGERING MOISTURE COULD ALLOW FOR THE DEVELOPMENT OF IFR VSBYS OVER KJMS ONCE AGAIN AFTER 00Z SATURDAY. && .FIRE WEATHER... THE FIRE WEATHER WATCH FOR FAR WESTERN NORTH DAKOTA TODAY HAS BEEN UPGRADED TO A RED FLAG WARNING. SOUTHWEST WINDS SUSTAINED TO 20 MPH WITH GUSTS OF 25 TO 30 MPH...MINIMUM RH VALUES NEAR 20 PERCENT AND TEMPERATURES IN THE LOWER 70S ARE EXPECTED...COUPLED WITH AN ABUNDANCE OF DRY FUELS WITH LITTLE GREEN UP. FOR SATURDAY...A COLD FRONT IS FORECAST TO STALL OUT BETWEEN THE US HIGHWAY 2 AND ND HIGHWAY 200 CORRIDORS DURING THE MORNING HOURS AND SLOWLY LIFT NORTH AS A WARM FRONT THROUGH THE DAY. HIGHS IN THE MID TO UPPER 70S ARE FORECAST SOUTH OF THE FRONT WITH AFTERNOON RH VALUES OF 20 TO 25 PERCENT. HOWEVER...THE OVERALL WIND FIELD ...AND THUS THE FIRE DANGER....IS FORECAST TO BE WEAKER COMPARED TO FRIDAY...WITH SOUTHWEST WINDS OF 10 TO 15 MPH EXPECTED SATURDAY AFTERNOON. HOWEVER...CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE ON SUNDAY....ESPECIALLY ACROSS THE SOUTHWEST. WINDY AND DRY CONDITIONS ARE POSSIBLE BEHIND A COLD FRONT WITH THE POTENTIAL FOR SUSTAINED WINDS OF 20 TO 30 MPH AND GUSTS POSSIBLY NEAR 40 MPH AS GOOD MIXING YIELDS RH VALUES DURING THE AFTERNOON AS LOW AS 20 PERCENT. A FIRE WEATHER WATCH MAY BE NEEDED FOR THE SOUTHWEST ON SUNDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR NDZ001-009-017-018-031>033-040- 041-043-044. DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR NDZ004-005- 012-013-022-023-025-036-037-047-048-050-051. && $$ SHORT TERM/FIRE...AYD LONG TERM/AVIATION....TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
347 AM CDT FRI MAR 30 2012 .SHORT TERM...TODAY THROUGH SATURDAY... THE HIGHLIGHTS OF THE SHORT TERM WILL BE FOG AND FIRE WEATHER FOR TODAY...FOLLOWED BY NEAR RECORD HIGHS ON SATURDAY FOR THE SOUTHERN HALF OF THE CWA. AS DEPICTED BY HRRR FORECAST CYCLES THROUGHOUT THE EARLY MORNING HOURS...WIDESPREAD DENSE FOG HAS PUSHED TOWARDS NORTH DAKOTA HIGHWAY 14 THROUGH THE NIGHT WITH WEAK EASTERLY SURFACE FLOW ON THE EASTERN SIDE OF A QUASI-STATIONARY FRONT. THE DENSE FOG ADVISORY ISSUED EARLIER TONIGHT REMAINS IN EFFECT THROUGH 17 UTC THIS MORNING FOR LOCATIONS GENERALLY ALONG AND EAST OF HIGHWAY 14...WITH PATCHY FOG POSSIBLY ALONG THE HIGHWAY 83 CORRIDOR. FOR THE REMAINDER OF TODAY THE FOCUS WILL BE ON CRITICAL FIRE WEATHER CONDITIONS ACROSS FAR WESTERN NORTH DAKOTA...IN GENERAL ALONG AND WEST OF NORTH DAKOTA HIGHWAY 8. THE 30/00 UTC GFS AND ITS ASSOCIATED STATISTICAL GUIDANCE HAVE TRENDED TOWARDS THE WEAKER WINDS OF THE NAM. HOWEVER...WITH ADIABATIC LAPSE RATES FORECAST THROUGH 700 MB BY LATE AFTERNOON...EXCELLENT MOMENT EM TRANSFER IS FORECAST TO YIELD SUSTAINED WINDS OF 15-20 KTS WITH GUST TO NEAR 25 KTS...AND AFTERNOON MINIMUM RELATIVE HUMIDITY VALUES NEAR 20 PERCENT WITH TEMPERATURES IN THE LOWER 70S. GIVEN THE ABUNDANCE OF DRY FUELS AND LITTLE GREEN UP...HAVE UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG WARNING FROM 18-02 UTC. FOR TONIGHT...THE AFOREMENTIONED STATIONARY FRONT IS FORECAST TO SHIFT EAST AS A WARM FRONT AS A CLIPPER SYSTEM PROPAGATES ACROSS SOUTHERN CANADA...WITH A COLD FRONT ENTERING THE FAR NORTHWEST LATE TONIGHT. GIVEN THE RELATIVELY MILD TEMPERATURES FORECAST TODAY AND BOUNDARY LAYER MIXING THROUGH THE NIGHT WITH THE PASSAGE OF THE CLIPPER TO THE NORTH...A RELATIVELY MILD OVERNIGHT IS FORECAST WITH LOWS GENERALLY IN THE 40S. THE AFOREMENTIONED COLD FRONT IS FORECAST TO STALL OUT BETWEEN THE US HIGHWAY 2 AND ND HIGHWAY 200 CORRIDORS ON SATURDAY MORNING AND SLOWLY LIFT NORTH THROUGH THE DAY AS A WARM FRONT. RECORD HIGH TEMPERATURES ARE POSSIBLE SOUTH OF THE FRONT ON SATURDAY. SHOWN BELOW ARE THE FORECAST AND RECORD HIGHS FOR SELECT LOCATIONS ACROSS THE CWA. SITE FORECAST RECORD YEAR DICKINSON 76 75 1964 MINOT 70 68 1963 BISMARCK 74 75 2003 JAMESTOWN 71 77 1963 THESE FORECAST HIGHS ARE COOLER COMPARED TO PREVIOUS FORECASTS...LARGELY DUE LOWER MAGNITUDES OF FORECAST MIXING...WHICH HOWEVER WILL HELP TO KEEP FIRE WEATHER CONDITIONS FROM REACHING CRITICAL LEVELS. .LONG TERM...SATURDAY NIGHT THROUGH THURSDAY... THE MEDIUM RANGE MODELS CONTINUE TO TREND DRIER AND DRIER WITH RESPECT TO THE NEXT LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE REGION THIS WEEKEND. THE ECMWF/GFS/GEM ARE IN FAIRLY GOOD AGREEMENT WITH THE OVERALL DRY/WARM WEATHER PATTERN OVER NORTH DAKOTA NEXT WEEK. AS A RESULT...DECIDED TO USE A BLEND OF SOLUTIONS FOR THIS FORECAST PACKAGE. SURFACE CYCLOGENESIS IS FORECAST TO DEVELOP ACROSS THE CANADIAN ROCKIES SATURDAY NIGHT. A STRENGTHENING LOW-LEVEL JET COMBINED WITH INCREASING DYNAMICS ALOFT SHOULD GENERATE A SLIGHT CHANCE OF SHOWERS NORTH (PROXIMATE TO THE STRONGEST UPPER DYNAMICS) SATURDAY NIGHT. THE SHOWALTER INDEX INDICATES THERE WILL BE A POTENTIAL FOR THUNDERSTORM ACTIVITY NORTHWEST FROM 00Z-06Z...THEN MID-LEVEL LAPSE RATES BECOME RELATIVELY MORE STABLE AFTER 06Z PRECLUDING ANY THUNDERSTORM DEVELOPMENT AFTER MIDNIGHT SATURDAY NIGHT. THE SLIGHT CHANCES FOR SHOWERS WILL CONTINUE NORTH (AGAIN...PROXIMATE TO THE STRONGEST FORCING) SUNDAY AS THE LOW LIFTS INTO NORTHERN SASKATCHEWAN AND PUSHES A FRONT THROUGH NORTH DAKOTA. WINDY CONDITIONS WILL DEVELOP IN THE WAKE OF THE FRONT WEST AND CENTRAL. HUMIDITIES WILL ALSO PLUMMET WITH A VERY HIGH FIRE DANGER EXPECTED SOUTHWEST OF THE MISSOURI RIVER SUNDAY AFTERNOON. HIGH PRESSURE BUILDING INTO THE STATE WILL MAINTAIN BREEZY TO WINDY CONDITIONS ACROSS WESTERN AND CENTRAL NORTH DAKOTA SUNDAY NIGHT AND MONDAY. THE COMBINATION OF WINDS AND DRY CONDITIONS WILL GENERATE A VERY HIGH FIRE DANGER MAINLY ALONG AND SOUTH OF HIGHWAY 2 MONDAY AFTERNOON. AN AMPLIFYING UPPER LEVEL RIDGE IS FORECAST TO BUILD OVER THE CENTRAL GREAT PLAINS TUESDAY THROUGH THURSDAY. DRY CONDITIONS AND A WARMING TREND ARE EXPECTED THROUGH THE END OF THE FORECAST PERIOD. && .AVIATION...LIGHT WINDS AND A STABLE/MOIST BOUNDARY LAYER WILL MAINTAIN LIFR CONDITIONS IN DENSE FOG ACROSS KJMS THROUGH THE MID TO LATE MORNING HOURS. MVFR VSBYS WILL BE POSSIBLE FROM KMOT-KBIS THROUGH THE EARLY MORNING HOURS. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST DURING THE MORNING HOURS WITH VFR CONDITIONS EXPECTED AREA WIDE BY THIS AFTERNOON. LINGERING MOISTURE COULD ALLOW FOR THE DEVELOPMENT OF IFR VSBYS OVER KJMS ONCE AGAIN AFTER 00Z SATURDAY. && .FIRE WEATHER... THE FIRE WEATHER WATCH FOR FAR WESTERN NORTH DAKOTA TODAY HAS BEEN UPGRADED TO A RED FLAG WARNING. SOUTHWEST WINDS SUSTAINED TO 20 MPH WITH GUSTS OF 25 TO 30 MPH...MINIMUM RH VALUES NEAR 20 PERCENT AND TEMPERATURES IN THE LOWER 70S ARE EXPECTED...COUPLED WITH AN ABIDANCE OF DRY FUELS WITH LITTLE GREEN UP. FOR SATURDAY...A COLD FRONT IS FORECAST TO STALL OUT BETWEEN THE US HIGHWAY 2 AND ND HIGHWAY 200 CORRIDORS DURING THE MORNING HOURS AND SLOWLY LIFT NORTH AS A WARM FRONT THROUGH THE DAY. HIGHS IN THE MID TO UPPER 70S ARE FORECAST SOUTH OF THE FRONT WITH AFTERNOON RH VALUES OF 20 TO 25 PERCENT. HOWEVER...THE OVERALL WIND FIELD ...AND THUS THE FIRE DANGER....IS FORECAST TO BE WEAKER COMPARED TO FRIDAY...WITH SOUTHWEST WINDS OF 10 TO 15 MPH EXPECTED SATURDAY AFTERNOON. HOWEVER...CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE ON SUNDAY....ESPECIALLY ACROSS THE SOUTHWEST. WINDY AND DRY CONDITIONS ARE POSSIBLE BEHIND A COLD FRONT WITH THE POTENTIAL FOR SUSTAINED WINDS OF 20 TO 30 MPH AND GUSTS POSSIBLY NEAR 40 MPH AS GOOD MIXING YIELDS RH VALUES DURING THE AFTERNOON AS LOW AS 20 PERCENT. A FIRE WEATHER WATCH MAY BE NEEDED FOR THE SOUTHWEST ON SUNDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR NDZ001-009-017-018-031>033-040- 041-043-044. DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR NDZ004-005- 012-013-022-023-025-036-037-047-048-050-051. && $$ SHORT TERM...AYD LONG TERM....TM AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1200 AM CDT FRI MAR 30 2012 .DISCUSSION... QUICK UPDATE FOR THE ISSUANCE OF A DENSE FOG ADVISORY THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY EXTENDING WEST TOWARDS NORTH DAKOTA HIGHWAYS 3 AND 14. THE LATEST HRRR LOW LEVEL CLOUD COVER AND VISIBILITY FORECASTS AND THE 21 UTC SREF PROBABILITIES OF VISIBILITY BELOW ONE MILE SUPPORT THE CONTINUATION AND EXPANSION OF FOG WEST THROUGH THE OVERNIGHT HOURS. && .AVIATION... FOG SHOWING UP AT JAMESTOWN IN LIGHT WIND REGION. ADDED SOME REDUCED VISIBILITY TO IFR THROUGH THE NIGHT UNTIL 8 AM CDT. OTHERWISE VFR AT ALL OTHER TAF SITES THROUGH THE PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR NDZ001-009-017-018-031>033-040-041-043-044. DENSE FOG ADVISORY UNTIL 10 AM CDT FRIDAY FOR NDZ004-005-012-013- 022-023-025-036-037-047-048-051. && $$ UPDATE..AYD AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1121 PM CDT THU MAR 29 2012 .DISCUSSION... QUICK UPDATE TO ADD PATCHY DENSE FOG TO THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY THROUGH 06 UTC...SPREADING THE FOG THEREAFTER WEST TOWARDS NORTH DAKOTA HIGHWAY 14...WHICH IS IN AGREEMENT WITH THE LATEST HRRR LOW LEVEL CLOUD COVER AND VISIBILITY FORECASTS AND THE 21 UTC SREF PROBABILITIES OF VISIBILITY BELOW ONE MILE. WILL CONTINUE TO MONITOR TRENDS...AND A DENSE FOG ADVISORY MAY BE NEEDED AT SOME POINT TONIGHT. ALL OTHER FORECAST FIELDS WERE ON TRACK AND ADJUSTED TO THE LATEST 04 UTC OBSERVED TRENDS. && .AVIATION... FOG SHOWING UP AT JAMESTOWN IN LIGHT WIND REGION. ADDED SOME REDUCED VISIBILITY TO IFR THROUGH THE NIGHT UNTIL 8 AM CDT. OTHERWISE VFR AT ALL OTHER TAF SITES THROUGH THE PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING FOR NDZ001-009-017-018-031>033-040-041-043-044. && $$ SHORT TERM...AYD AVIATION...WAA
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
130 PM CDT FRI MAR 30 2012 .DISCUSSION.../ISSUED AT 1045 AM CDT/ A BAND OF MID CLOUDS OVERSPREADING MUCH OF THE AREA HAS ALLOWED FOG TO PERSIST GENERALLY EAST OF THE INTERSTATE 29 CORRIDOR THROUGH THE MORNING...SO EARLIER EXTENDED DENSE FOG ADVISORY THROUGH 17Z. OTHERWISE...RADAR PICKING UP A BROAD AREA OF ECHOES THROUGH THE JAMES RIVER VALLEY WITH MID LEVEL WAVE PUSHING OUT OF CENTRAL SOUTH DAKOTA. OBS HAVE NOT REPORTED ANY RAIN WITH THIS ACTIVITY...AND CEILINGS ARE RUNNING AROUND 9 TO 10 KFT...SO NOT MUCH REACHING THE GROUND AT THIS POINT...SO JUST EXPANDED THE MENTION OF SPRINKLES EASTWARD TO I 29 INTO THE AFTERNOON. ALSO LOWERED HIGH TEMPERATURES IN PORTIONS OF OUR NORTH AND EAST WHERE THINK CLOUDS WILL REMAIN THE LONGEST. UPDATES OUT. && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ GENERALLY VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD WITH RELATIVELY LIGHT SOUTHEASTERLY SURFACE FLOW AND PERIODS OF CEILINGS IN THE 10 TO 12 KFT RANGE. CANNOT RULE OUT SOME LOCALLY REDUCED VISIBILITIES BETWEEN 10Z TO 14Z ON SATURDAY IF WINDS GO LIGHT ENOUGH. && .PREV DISCUSSION.../ISSUED AT 347 AM CDT/ AREAS OF FOG HAVE DEVELOPED OVERNIGHT EAST OF THE JAMES RIVER VALLEY. AM WATCHING AREAS UP NORTH OF 90 AND EAST OF I-29 WHERE VISIBILITIES HAVE CONSISTENTLY BEEN THE LOWEST DUE TO INCREASED AMOUNTS OF LOW LEVEL MOISTURE FROM THE RAIN THURSDAY EVENING. FOG APPEARS TO BE RELATIVELY SHALLOW RIGHT NOW...BUT RUC MODEL SOUNDINGS SUGGESTS OVER THE NEXT FEW HOURS FOG WILL THICKEN. RAIN TOTALS WERE FAIRLY LIGHT ESPECIALLY SOUTH OF I-90 SO THERE IS SOME QUESTION AS TO HOW THICK THE FOG WILL GET DOW THERE. IF DENSE FOG BECOMES MORE WIDESPREAD OVER THE PRE-DAWN HOURS...WILL ISSUE DENSE FOG ADVISORY. OTHERWISE...EXPECTING FOG TO GRADUALLY BURN OFF TODAY LEADING TO A PLEASANT DAY ACROSS THE AREA. SOUTHEAST WINDS WILL GRADUALLY INCREASE FROM WEST TO EAST TODAY...BUT WILL STILL NOT BE ALL THAT STRONG. TEMPERATURES WILL STILL BE 20-25 DEGREES ABOVE NORMAL. GREATEST MIXING IS IN THE WEST TODAY...AND SOME CONCERN ACROSS SOUTHWEST MINNESOTA THAT LOW LEVEL MOISTURE MAY NOT MIX OUT TODAY. AS SUCH...ADDED MENTION OF PATCHY FOG THERE BUT MAY NEED TO BEEF UP WORDING IN FUTURE UPDATES. WARMING TREND EXPECTED OVER THE WEEKEND. APPEARS AS THOUGH FAIRLY DENSE CIRRUS SHIELD WILL HINDER WARMING POTENTIAL ON SATURDAY...HOWEVER...SUNDAY LOOKS TO BE DOWNRIGHT HOT WITH STRONG UPPER LEVEL RIDGE BUILDING INTO THE AREA. HAVE INCREASED FORECAST HIGHS SLIGHTLY...ESPECIALLY ACROSS WESTERN CWA WITH SLOWER PROGRESSION OF THE FRONT. CURRENT FORECAST HIGHS ARE AROUND 3 DEGREES ABOVE RECORD IN MOST LOCATIONS. NOT A LOT OF MOISTURE OR UPPER LEVEL DYNAMICS WITH FRONT ON SUNDAY NIGHT. AS SUCH...CONTINUED TO DECREASE POP MENTION SUNDAY NIGHT INTO MONDAY MORNING. ALTHOUGH WINDS WILL BE STRONG OUT OF THE NORTHWEST AND TEMPERATURES WILL BE MUCH COOLER THAN THE PREVIOUS DAY...TEMPERATURES STILL APPEAR TO BE WELL ABOVE NORMAL ON MONDAY. APPEARS AS THOUGH THERE WILL BE A GENERAL WARMING TREND NEXT WEEK...WITH THE POTENTIAL FOR 80S RETURNING BY WEEKS END. && .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
1045 AM CDT FRI MAR 30 2012 .DISCUSSION.../ISSUED AT 1045 AM CDT/ A BAND OF MID CLOUDS OVERSPREADING MUCH OF THE AREA HAS ALLOWED FOG TO PERSIST GENERALLY EAST OF THE INTERSTATE 29 CORRIDOR THROUGH THE MORNING...SO EARLIER EXTENDED DENSE FOG ADVISORY THROUGH 17Z. OTHERWISE...RADAR PICKING UP A BROAD AREA OF ECHOES THROUGH THE JAMES RIVER VALLEY WITH MID LEVEL WAVE PUSHING OUT OF CENTRAL SOUTH DAKOTA. OBS HAVE NOT REPORTED ANY RAIN WITH THIS ACTIVITY...AND CEILINGS ARE RUNNING AROUND 9 TO 10 KFT...SO NOT MUCH REACHING THE GROUND AT THIS POINT...SO JUST EXPANDED THE MENTION OF SPRINKLES EASTWARD TO I 29 INTO THE AFTERNOON. ALSO LOWERED HIGH TEMPERATURES IN PORTIONS OF OUR NORTH AND EAST WHERE THINK CLOUDS WILL REMAIN THE LONGEST. UPDATES OUT. && .PREV DISCUSSION.../ISSUED AT 347 AM CDT/ AREAS OF FOG HAVE DEVELOPED OVERNIGHT EAST OF THE JAMES RIVER VALLEY. AM WATCHING AREAS UP NORTH OF 90 AND EAST OF I-29 WHERE VISIBILITIES HAVE CONSISTENTLY BEEN THE LOWEST DUE TO INCREASED AMOUNTS OF LOW LEVEL MOISTURE FROM THE RAIN THURSDAY EVENING. FOG APPEARS TO BE RELATIVELY SHALLOW RIGHT NOW...BUT RUC MODEL SOUNDINGS SUGGESTS OVER THE NEXT FEW HOURS FOG WILL THICKEN. RAIN TOTALS WERE FAIRLY LIGHT ESPECIALLY SOUTH OF I-90 SO THERE IS SOME QUESTION AS TO HOW THICK THE FOG WILL GET DOW THERE. IF DENSE FOG BECOMES MORE WIDESPREAD OVER THE PRE-DAWN HOURS...WILL ISSUE DENSE FOG ADVISORY. OTHERWISE...EXPECTING FOG TO GRADUALLY BURN OFF TODAY LEADING TO A PLEASANT DAY ACROSS THE AREA. SOUTHEAST WINDS WILL GRADUALLY INCREASE FROM WEST TO EAST TODAY...BUT WILL STILL NOT BE ALL THAT STRONG. TEMPERATURES WILL STILL BE 20-25 DEGREES ABOVE NORMAL. GREATEST MIXING IS IN THE WEST TODAY...AND SOME CONCERN ACROSS SOUTHWEST MINNESOTA THAT LOW LEVEL MOISTURE MAY NOT MIX OUT TODAY. AS SUCH...ADDED MENTION OF PATCHY FOG THERE BUT MAY NEED TO BEEF UP WORDING IN FUTURE UPDATES. WARMING TREND EXPECTED OVER THE WEEKEND. APPEARS AS THOUGH FAIRLY DENSE CIRRUS SHIELD WILL HINDER WARMING POTENTIAL ON SATURDAY...HOWEVER...SUNDAY LOOKS TO BE DOWNRIGHT HOT WITH STRONG UPPER LEVEL RIDGE BUILDING INTO THE AREA. HAVE INCREASED FORECAST HIGHS SLIGHTLY...ESPECIALLY ACROSS WESTERN CWA WITH SLOWER PROGRESSION OF THE FRONT. CURRENT FORECAST HIGHS ARE AROUND 3 DEGREES ABOVE RECORD IN MOST LOCATIONS. NOT A LOT OF MOISTURE OR UPPER LEVEL DYNAMICS WITH FRONT ON SUNDAY NIGHT. AS SUCH...CONTINUED TO DECREASE POP MENTION SUNDAY NIGHT INTO MONDAY MORNING. ALTHOUGH WINDS WILL BE STRONG OUT OF THE NORTHWEST AND TEMPERATURES WILL BE MUCH COOLER THAN THE PREVIOUS DAY...TEMPERATURES STILL APPEAR TO BE WELL ABOVE NORMAL ON MONDAY. APPEARS AS THOUGH THERE WILL BE A GENERAL WARMING TREND NEXT WEEK...WITH THE POTENTIAL FOR 80S RETURNING BY WEEKS END. && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ HAD TO MAKE A FEW QUICK CHANGES. WIDESPREAD MVFR TO IFR CEILINGS CAN BE EXPECTED ALONG AND EAST IF I29 THROUGH 14Z FRIDAY ALONG WITH VISIBILITIES BELOW 1 MILE AT TIMES ON FOG. SHOWERS MAY LINGER THROUGH 08Z EXTREME EASTERN PART OF AREA WELL EAST OF TAF SITES. OTHERWISE GENERALLY VFR CONDITIONS SHOULD RULE THROUGH 31/06Z. LOCAL EXCEPTIONS SEEM POSSIBLE IN THE FORM OF 3-5SM IN LIGHT FOG 08Z-13Z. AM MENTIONING THIS REDUCTION IN HON AND FSD TAFS BUT NOT IN SUX TAF DUE TO LONGER LINGERING NORTHERLY SURFACE FLOW ALTHOUGH THIS S AREA AND EAST WILL HAVE THE WEAKEST DRYING. NO OTHER POSSIBLE EXCEPTION SEEN WITH DRY REGIME DEVELOPING. A FEW CEILINGS AROUND 10K FEET 12Z-31/00Z IS PROBABLY THE WORST CONDITION FORESEEN OTHER THAN THE ABOVE MENTIONED LIGHT FOG. / WILLIAMS && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ071-072- 080-097. NE...NONE. SD...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR SDZ039-040- 054>056. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
444 AM CDT FRI MAR 30 2012 .DISCUSSION... ISSUED A SMALL DENSE FOG ADVISORY FOR THE AREA OF CONCERN OUTLINED IN THE DISCUSSION BELOW. && .PREV DISCUSSION.../ISSUED AT 347 AM CDT/ AREAS OF FOG HAVE DEVELOPED OVERNIGHT EAST OF THE JAMES RIVER VALLEY. AM WATCHING AREAS UP NORTH OF 90 AND EAST OF I-29 WHERE VISIBILITIES HAVE CONSISTENTLY BEEN THE LOWEST DUE TO INCREASED AMOUNTS OF LOW LEVEL MOISTURE FROM THE RAIN THURSDAY EVENING. FOG APPEARS TO BE RELATIVELY SHALLOW RIGHT NOW...BUT RUC MODEL SOUNDINGS SUGGESTS OVER THE NEXT FEW HOURS FOG WILL THICKEN. RAIN TOTALS WERE FAIRLY LIGHT ESPECIALLY SOUTH OF I-90 SO THERE IS SOME QUESTION AS TO HOW THICK THE FOG WILL GET DOW THERE. IF DENSE FOG BECOMES MORE WIDESPREAD OVER THE PRE-DAWN HOURS...WILL ISSUE DENSE FOG ADVISORY. OTHERWISE...EXPECTING FOG TO GRADUALLY BURN OFF TODAY LEADING TO A PLEASANT DAY ACROSS THE AREA. SOUTHEAST WINDS WILL GRADUALLY INCREASE FROM WEST TO EAST TODAY...BUT WILL STILL NOT BE ALL THAT STRONG. TEMPERATURES WILL STILL BE 20-25 DEGREES ABOVE NORMAL. GREATEST MIXING IS IN THE WEST TODAY...AND SOME CONCERN ACROSS SOUTHWEST MINNESOTA THAT LOW LEVEL MOISTURE MAY NOT MIX OUT TODAY. AS SUCH...ADDED MENTION OF PATCHY FOG THERE BUT MAY NEED TO BEEF UP WORDING IN FUTURE UPDATES. WARMING TREND EXPECTED OVER THE WEEKEND. APPEARS AS THOUGH FAIRLY DENSE CIRRUS SHIELD WILL HINDER WARMING POTENTIAL ON SATURDAY...HOWEVER...SUNDAY LOOKS TO BE DOWNRIGHT HOT WITH STRONG UPPER LEVEL RIDGE BUILDING INTO THE AREA. HAVE INCREASED FORECAST HIGHS SLIGHTLY...ESPECIALLY ACROSS WESTERN CWA WITH SLOWER PROGRESSION OF THE FRONT. CURRENT FORECAST HIGHS ARE AROUND 3 DEGREES ABOVE RECORD IN MOST LOCATIONS. NOT A LOT OF MOISTURE OR UPPER LEVEL DYNAMICS WITH FRONT ON SUNDAY NIGHT. AS SUCH...CONTINUED TO DECREASE POP MENTION SUNDAY NIGHT INTO MONDAY MORNING. ALTHOUGH WINDS WILL BE STRONG OUT OF THE NORTHWEST AND TEMPERATURES WILL BE MUCH COOLER THAN THE PREVIOUS DAY...TEMPERATURES STILL APPEAR TO BE WELL ABOVE NORMAL ON MONDAY. APPEARS AS THOUGH THERE WILL BE A GENERAL WARMING TREND NEXT WEEK...WITH THE POTENTIAL FOR 80S RETURNING BY WEEKS END. && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ HAD TO MAKE A FEW QUICK CHANGES. WIDESPREAD MVFR TO IFR CEILINGS CAN BE EXPECTED ALONG AND EAST IF I29 THROUGH 14Z FRIDAY ALONG WITH VISIBILITIES BELOW 1 MILE AT TIMES ON FOG. SHOWERS MAY LINGER THROUGH 08Z EXTREME EASTERN PART OF AREA WELL EAST OF TAF SITES. OTHERWISE GENERALLY VFR CONDITIONS SHOULD RULE THROUGH 31/06Z. LOCAL EXCEPTIONS SEEM POSSIBLE IN THE FORM OF 3-5SM IN LIGHT FOG 08Z-13Z. AM MENTIONING THIS REDUCTION IN HON AND FSD TAFS BUT NTO IN SUX TAF DUE TO LONGER LINGERING NORTHERLY SURFACE FLOW ALTHOUGH THIO S AREA AND EAST WILL HAVE THE WEAKEST DRYING. NO OTHER POSSIBLE EXCEPTION SEEN WITH DRY REGIME DEVELOPING. A FEW CEILINGS AROUND 10K FEET 12Z-31/00Z IS PROBABLY THE WORST CONDITION FORSEEN OTHER THAN THE ABOVE MENTIONED LIGHT FOG. / WILLIAMS && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ071-072- 080-097. NE...NONE. SD...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR SDZ039-040- 054>056. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
635 PM CDT SAT MAR 31 2012 .DISCUSSION... EXPECT VFR CONDITIONS TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR THE NEXT 24 HOURS. AVIATION BELOW HAS ADDITIONAL INFORMATION. && .AVIATION... MODELS CONTINUE TO HOLD A SURFACE TROUGH OF LOW PRESSURE...AND AN ASSOCIATED SURFACE DRYLINE...IN THE TEXAS AND NEW MEXICO AREA FOR THE NEXT 24 HOURS. THE LATEST RUC INDICATES THE SURFACE PRESSURE GRADIENT WILL INCREASE ACROSS WEST CENTRAL TEXAS OVERNIGHT TONIGHT. THUS...LOOK FOR GUSTY SOUTHWEST SURFACE WINDS TO DOMINATE WEST CENTRAL TEXAS BY 06Z TONIGHT. FOR TOMORROW AFTERNOON...WATCH FOR STRONGER SOUTHWEST SURFACE WINDS AS THE SURFACE PRESSURE GRADIENT STRENGTHENS ACROSS WEST CENTRAL TEXAS. HUBER && .PREV DISCUSSION... /ISSUED 334 PM CDT SAT MAR 31 2012/ SHORT TERM... AN UPPER LEVEL RIDGE WILL AMPLIFY THROUGH TOMORROW AS IT BUILDS EAST OF THE FORECAST AREA AHEAD OF AN APPROACHING UPPER LEVEL TROUGH... WHICH WILL BE OVER THE SOUTHERN ROCKIES BY LATE TOMORROW. HOT AND DRY WEATHER WILL CONTINUE ACROSS WEST CENTRAL TEXAS TOMORROW WITH LOW TO UPPER 90S OVER THE CWA...THE WARMEST TEMPERATURES SHOULD BE OVER THE NORTHERN HALF OF THE CWA AS THE 850MB THERMAL RIDGE LIFTS FURTHER TO THE NORTH. 15 LONG TERM... THE DEEP CLOSED LOW OFF THE PACNW COAST WILL BE A PLAYER IN OUR WEATHER AS THE LONG TERM OPENS BUT THE MEDIUM RANGE MODELS CONTINUE TO STRUGGLE WITH THE TIMING. THE LATEST RUNS SUGGEST THAT THIS FEATURE WILL SLOW AS IT MOVES ACROSS THE SOUTHWEST CONUS...LIFTING NORTHEAST ACROSS THE TX PANHANDLE AFTER 00Z WEDNESDAY. THIS LATER ARRIVAL WILL LIKELY RESULT IN THE DRYLINE SETTING UP FARTHER WEST THAN PREVIOUS ANTICIPATED GIVEN WEAKER FORCING. STRONG SYNOPTIC LIFT /DEPICTED BY H5-H3 Q VECTOR CONVERGENCE/ IS PROGGED TO REMAIN WEST OF THE CWA UNTIL MONDAY NIGHT BY WHICH TIME THE DRYLINE WILL BE RETREATING. THUNDERSTORMS WILL BE POSSIBLE ALONG AND EAST OF THE DRYLINE LATE MONDAY AFTERNOON. SURFACE TEMPS IN THE MID/UPPER 80S AND DEWPOINTS WILL RESULT IN SIGNIFICANT INSTABILITY /SBCAPES OF 1500-3000/ BUT A SLOWER ARRIVAL OF SYNOPTIC ASCENT MAY RESULT IN THE CAP HOLDING STRONG AND LIMITING THE CONVECTIVE POTENTIAL /ESPECIALLY IN THE EAST IN THE AREA OF STRONGEST INSTABILITY/...MUCH OF THE CHAGRIN OF THE SOUTHERN PLAINS CHASE COMMUNITY. I OPTED TO MAINTAIN THE INHERITED POPS ON THE CENTRAL AND EAST ON MONDAY AFTERNOON BUT EXPANDED THEM WEST MONDAY NIGHT AND TUESDAY TO ACCOUNT FOR THE SLOWER TIMING. COOLER TEMPS ARE EXPECTED ON TUESDAY AS A PACIFIC COLD FRONT MOVES THROUGH THE AREA. I LOWERED MAX TEMPS INTO THE MID/UPPER 70S BUT FEEL I MAY STILL BE A FEW DEGREES ON THE WARM SIDE BASED ON H85 TEMPS. I AM NOT SOLD ON THE AGGRESSIVE RETURN OF SOUTHERLY FLOW SHOWN BY THE GFS AND LEANED MORE HEAVILY ON THE ECMWF SOLUTION IN THE POST FRONTAL ENVIRONMENT. WITH THAT SAID...I KEPT MAX TEMPS GENERALLY AT OR JUST BELOW 80 DEGREES ON WEDNESDAY BUT DRY CONDITIONS WILL RESULT IN A VERY PLEASANT DAY. MIN TEMPS TUESDAY NIGHT ARE EXPECTED TO BE IN THE MID/UPPER 50S...WARMING SLIGHTLY /LOWER 50S/ BY WEDNESDAY NIGHT. BY THURSDAY...THE H85 THERMAL RIDGE WILL BUILD BACK OVER THE AREA WITH INCREASING SOUTHERLY WINDS. TEMPS ARE EXPECTED TO WARM BACK INTO THE MID 80S. THESE SOUTHERLY WINDS WILL BRING THE LOW LEVEL MOISTURE BACK THURSDAY NIGHT AND FRIDAY. THE MODELS ARE HINTING AT SOME CONVECTION DEVELOPING OVER WEST TX FRIDAY EVENING ALONG THE DRYLINE BUT MY GUT SAYS THAT MOISTURE RETURN WILL NOT BE ADEQUATE TO SUPPORT MORE THAN FEW HIGH BASED STORMS. THUS...NO POPS WERE INCLUDED AT THIS TIME. HOWEVER...CONSIDERABLE UNCERTAINTY EXISTS AT THIS TIME. TEMPS WILL AGAIN BE WARM ON FRIDAY WITH HIGHS IN THE MID/UPPER 80S. THE GFS/DGEX DEPICT A WEAK COLD FRONT STALLING OVER THE AREA BY NEXT WEEKEND...ENHANCING RAIN CHANCES. HOWEVER...THE ECMWF KEEPS THIS BOUNDARY NORTH OF THE CWA IN CONJUNCTION WITH THE UPPER LEVEL SYSTEM. THE ECMWF ALSO PUSHES H5 HEIGHTS UP NEAR 585DM WITH THE MID LEVEL ANTICYCLONE CENTERED OVER DEEP SOUTH TX WHEREAS THE GFS KEEPS HEIGHTS AROUND 580DM WITH THE RIDGE CENTERED OVER THE GULF OF MEXICO. I WILL LET THE MODELS CONTINUE TO TEASE US OVER THE NEXT FEW DAYS BEFORE JUMPING ON ANY PARTICULAR SOLUTION. JOHNSON FIRE WEATHER... ELEVATED FIRE WEATHER CONDITIONS CAN BE EXPECTED SUNDAY OVER THE BIG COUNTRY...CONCHO VALLEY AND THE NORTHERN EDWARDS PLATEAU WITH UNSEASONABLY HOT TEMPERATURES IN THE 90S CONTINUING...ACCOMPANIED BY LOW RELATIVE HUMIDITY VALUES...AND SOUTHWEST WINDS BETWEEN 15 AND 20 MPH. CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE MAINLY WEST OF A LINE FROM HASKELL TO STERLING CITY SUNDAY AFTERNOON WITH 20 FOOT SOUTHWEST WINDS APPROACHING 20 MPH AND RELATIVE HUMIDITY VALUES DROPPING TO LESS THAN 10 PERCENT. 15 && .PRELIMINARY POINT TEMPS/POPS... ABILENE 65 96 65 85 52 / 0 0 0 20 30 SAN ANGELO 60 96 62 86 51 / 0 0 0 20 20 JUNCTION 62 93 64 87 51 / 10 10 10 20 30 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUBER
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
525 PM CDT FRI MAR 30 2012 .AVIATION... FOR THE 00Z TAFS...VFR CONDITIONS ARE ANTICIPATED. THERE IS A VERY MINIMAL THREAT FOR IFR CIGS TO DEVELOP AT KAMA 09-14Z...BUT THINK THESE SHOULD REMAIN EAST OF THE TAF SITE. JACKSON && .PREV DISCUSSION... /ISSUED 420 PM CDT FRI MAR 30 2012/ DISCUSSION... RECORD OR NEAR RECORD HEAT EXPECTED THIS WEEKEND...FOLLOWED BY A COOL DOWN...RAIN CHANCES...AND POSSIBLY STRONG NORTHERLY WINDS EARLY NEXT WEEK. FOR THE REST OF THIS AFTERNOON AND EVENING...REMOVED THE ISOLATED THUNDERSTORM MENTION. STILL A GOOD AMOUNT OF LOW-LEVEL MOISTURE AND POTENTIAL INSTABILITY ACROSS CENTRAL AND EASTERN AREAS...BUT DON/T THINK WE/LL TAP INTO IT. LAPS AND RUC ANALYSIS DATA SHOW 75 J/KG OR MORE OF CIN STILL IN PLACE ACROSS THE EAST...AND ANY FORCING FROM MID-LEVEL SHORTWAVE WILL BE SHIFTING INTO WESTERN OK WITH SUBSIDENCE BUILDING IN BEHIND THIS WAVE AND AHEAD OF SHORTWAVE RIDGE TO THE WEST. VERY FLAT CU FIELD THAT GREW OUT OF THIS MORNING/S STRATUS CONTINUES TO PUSH EASTWARD LATE THIS AFTERNOON IN ASSOCIATION WITH WEAK LIFT FROM AFOREMENTIONED SHORTWAVE...WITH MAINLY CLEAR SKIES TO THE WEST ASIDE FROM A FEW FAIR WEATHER CU. AFTER MIDNIGHT...MAY SEE SOME FOG DEVELOP ONCE AGAIN. LOW-LEVELS WILL REMAIN MOIST AND WINDS WILL BE LIGHT UNDER MOSTLY CLEAR SKIES...POTENTIALLY LEADING TO SOME RADIATION FOG. SHORTWAVE UPPER RIDGING WILL BE IN PLACE ON SUNDAY...WHILE A WEAK LEE TROUGH DEVELOPS AT THE SURFACE. SOUTH/SOUTHWEST WINDS WILL RETURN BUT LOOK TO REMAIN FAIRLY LIGHT /AOB 15 MPH/. SHOULD BE A NICE SPRING DAY AS TEMPS CLIMB INTO THE 80S. RECORD HIGH OF 87F MAY FALL AT KDHT. MODELS HAVE ALL COME ON BOARD WITH CLOSING OFF AN UPPER LOW AS THE NEXT UPPER TROUGH WORKS ACROSS THE SOUTHERN ROCKIES. THIS LEADS TO A SLOWER PROGRESSION OF THE UPPER SYSTEM...AND IN TURN...WINDS ON SUNDAY STILL LOOKING WEAKER THAN ONCE THOUGHT EARLIER THIS WEEK. IT WILL STILL BE WINDY AS THE SURFACE GRADIENT TIGHTENS IN RESPONSE TO A DEVELOPING LOW OVER THE CENTRAL HIGH PLAINS...BUT CERTAINLY NOTHING OUT OF THE ORDINARY FOR THIS PART OF THE COUNTRY. GENERALLY LOOKING AT SOUTHWEST WINDS IN THE 20-30 MPH RANGE WITH GUSTS UP TO 40 MPH...AND LIKELY A LITTLE WEAKER THAN THIS IN THE EAST. HIGHS EXPECTED TO SOAR INTO THE UPPER 80S TO MID 90S...PUTTING RECORDS IN JEOPARDY AT KAMA...KDHT...AND KBGD. STRONG COLD FRONT IS EXPECTED TO PUSH THROUGH MONDAY...AND NORTH WINDS MAY REACH ADVISORY LEVELS IN THE TIGHT GRADIENT. WILL SEE MUCH COOLER TEMPS MONDAY WITH ACTUAL READINGS DEPENDING ON THE FRONTAL TIMING...AND EVEN COOLER ON TUESDAY. QUESTION THEN BECOMES HOW LONG THE CLOSED LOW WILL LINGER AROUND THE AREA. GFS AND CMC GEM ARE FAIRLY PROGRESSIVE WITH THE SYSTEM...PUSHING IT EAST BY TUESDAY NIGHT. LATEST ECMWF IS SLOWER...KEEPING POTENTIAL FOR WRAPAROUND RAIN SHOWERS INTO WEDNESDAY. FOR NOW WILL BRING CHANCES FOR RAIN SHOWERS INTO THE WEST MONDAY AFTERNOON...EXPAND THEM AREA WIDE MONDAY NIGHT...AND THEN LINGER THEM IN THE NORTHEAST TUESDAY BEFORE DRYING THINGS OUT TUESDAY NIGHT. ONCE THE UPPER LOW PULLS EAST...WILL SEE REBOUNDING TEMPERATURES AND DRY CONDITIONS MID TO LATE NEXT WEEK. KB FIRE WEATHER... VERY WARM TEMPERATURES CAN BE EXPECTED ACROSS THE PANHANDLES THIS WEEKEND...WITH HIGHS FORECAST TO REACH THE 80S SATURDAY AND UPPER 80S TO MID 90S SUNDAY. RELATIVE HUMIDITIES WILL FALL TO 10 TO 20 PERCENT ACROSS THE WESTERN AND CENTRAL PANHANDLES SATURDAY...BUT WINDS ARE FORECAST TO REMAIN BELOW 15 MPH...KEEPING FIRE WEATHER CONDITIONS BELOW ELEVATED LEVELS. SOUTHWEST WINDS WILL INCREASE ON SUNDAY AS SURFACE LOW PRESSURE DEVELOPS OVER THE CENTRAL HIGH PLAINS. A FIRE WEATHER WATCH HAS BEEN ISSUED FOR THE WESTERN AND CENTRAL PANHANDLES SUNDAY WHERE SOUTHWEST WINDS ARE EXPECTED TO INCREASE TO 20 TO 30 MPH WITH HIGHER GUSTS. ACROSS THE EASTERN PANHANDLES...WINDS ARE FORECAST TO BE SLIGHTLY WEAKER IN THE 15 TO 25 MPH RANGE. RELATIVE HUMIDITIES WILL FALL TO 5 TO 15 PERCENT AREA WIDE. A STRONG COLD FRONT WILL MOVE THROUGH ON MONDAY...WITH STRONG NORTH WINDS DEVELOPING BEHIND THE FRONT. RELATIVE HUMIDITIES EXPECTED TO STAY AROUND 20 PERCENT OR HIGHER DUE TO COOLER CONDITIONS...BUT THE WINDS WILL BE STRONG LEADING TO ELEVATED FIRE WEATHER CONDITIONS. ELEVATED FIRE WEATHER CONDITIONS MAY RETURN LATE NEXT WEEK AS TEMPERATURES WARM BACK UP AND SOUTH/SOUTHWEST WINDS RETURN. KB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...DALLAM...DEAF SMITH...HANSFORD...HARTLEY...HUTCHINSON...MOORE...OLDHAM... POTTER...RANDALL...SHERMAN. OK...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES: CIMARRON...TEXAS. && $$ JJ/JC
AREA FORECAST DISCUSSION
NWS AMARILLO TX
420 PM CDT FRI MAR 30 2012 .DISCUSSION... RECORD OR NEAR RECORD HEAT EXPECTED THIS WEEKEND...FOLLOWED BY A COOL DOWN...RAIN CHANCES...AND POSSIBLY STRONG NORTHERLY WINDS EARLY NEXT WEEK. FOR THE REST OF THIS AFTERNOON AND EVENING...REMOVED THE ISOLATED THUNDERSTORM MENTION. STILL A GOOD AMOUNT OF LOW-LEVEL MOISTURE AND POTENTIAL INSTABILITY ACROSS CENTRAL AND EASTERN AREAS...BUT DON/T THINK WE/LL TAP INTO IT. LAPS AND RUC ANALYSIS DATA SHOW 75 J/KG OR MORE OF CIN STILL IN PLACE ACROSS THE EAST...AND ANY FORCING FROM MID-LEVEL SHORTWAVE WILL BE SHIFTING INTO WESTERN OK WITH SUBSIDENCE BUILDING IN BEHIND THIS WAVE AND AHEAD OF SHORTWAVE RIDGE TO THE WEST. VERY FLAT CU FIELD THAT GREW OUT OF THIS MORNING/S STRATUS CONTINUES TO PUSH EASTWARD LATE THIS AFTERNOON IN ASSOCIATION WITH WEAK LIFT FROM AFOREMENTIONED SHORTWAVE...WITH MAINLY CLEAR SKIES TO THE WEST ASIDE FROM A FEW FAIR WEATHER CU. AFTER MIDNIGHT...MAY SEE SOME FOG DEVELOP ONCE AGAIN. LOW-LEVELS WILL REMAIN MOIST AND WINDS WILL BE LIGHT UNDER MOSTLY CLEAR SKIES...POTENTIALLY LEADING TO SOME RADIATION FOG. SHORTWAVE UPPER RIDGING WILL BE IN PLACE ON SUNDAY...WHILE A WEAK LEE TROUGH DEVELOPS AT THE SURFACE. SOUTH/SOUTHWEST WINDS WILL RETURN BUT LOOK TO REMAIN FAIRLY LIGHT /AOB 15 MPH/. SHOULD BE A NICE SPRING DAY AS TEMPS CLIMB INTO THE 80S. RECORD HIGH OF 87F MAY FALL AT KDHT. MODELS HAVE ALL COME ON BOARD WITH CLOSING OFF AN UPPER LOW AS THE NEXT UPPER TROUGH WORKS ACROSS THE SOUTHERN ROCKIES. THIS LEADS TO A SLOWER PROGRESSION OF THE UPPER SYSTEM...AND IN TURN...WINDS ON SUNDAY STILL LOOKING WEAKER THAN ONCE THOUGHT EARLIER THIS WEEK. IT WILL STILL BE WINDY AS THE SURFACE GRADIENT TIGHTENS IN RESPONSE TO A DEVELOPING LOW OVER THE CENTRAL HIGH PLAINS...BUT CERTAINLY NOTHING OUT OF THE ORDINARY FOR THIS PART OF THE COUNTRY. GENERALLY LOOKING AT SOUTHWEST WINDS IN THE 20-30 MPH RANGE WITH GUSTS UP TO 40 MPH...AND LIKELY A LITTLE WEAKER THAN THIS IN THE EAST. HIGHS EXPECTED TO SOAR INTO THE UPPER 80S TO MID 90S...PUTTING RECORDS IN JEOPARDY AT KAMA...KDHT...AND KBGD. STRONG COLD FRONT IS EXPECTED TO PUSH THROUGH MONDAY...AND NORTH WINDS MAY REACH ADVISORY LEVELS IN THE TIGHT GRADIENT. WILL SEE MUCH COOLER TEMPS MONDAY WITH ACTUAL READINGS DEPENDING ON THE FRONTAL TIMING...AND EVEN COOLER ON TUESDAY. QUESTION THEN BECOMES HOW LONG THE CLOSED LOW WILL LINGER AROUND THE AREA. GFS AND CMC GEM ARE FAIRLY PROGRESSIVE WITH THE SYSTEM...PUSHING IT EAST BY TUESDAY NIGHT. LATEST ECMWF IS SLOWER...KEEPING POTENTIAL FOR WRAPAROUND RAIN SHOWERS INTO WEDNESDAY. FOR NOW WILL BRING CHANCES FOR RAIN SHOWERS INTO THE WEST MONDAY AFTERNOON...EXPAND THEM AREA WIDE MONDAY NIGHT...AND THEN LINGER THEM IN THE NORTHEAST TUESDAY BEFORE DRYING THINGS OUT TUESDAY NIGHT. ONCE THE UPPER LOW PULLS EAST...WILL SEE REBOUNDING TEMPERATURES AND DRY CONDITIONS MID TO LATE NEXT WEEK. KB && .FIRE WEATHER... VERY WARM TEMPERATURES CAN BE EXPECTED ACROSS THE PANHANDLES THIS WEEKEND...WITH HIGHS FORECAST TO REACH THE 80S SATURDAY AND UPPER 80S TO MID 90S SUNDAY. RELATIVE HUMIDITIES WILL FALL TO 10 TO 20 PERCENT ACROSS THE WESTERN AND CENTRAL PANHANDLES SATURDAY...BUT WINDS ARE FORECAST TO REMAIN BELOW 15 MPH...KEEPING FIRE WEATHER CONDITIONS BELOW ELEVATED LEVELS. SOUTHWEST WINDS WILL INCREASE ON SUNDAY AS SURFACE LOW PRESSURE DEVELOPS OVER THE CENTRAL HIGH PLAINS. A FIRE WEATHER WATCH HAS BEEN ISSUED FOR THE WESTERN AND CENTRAL PANHANDLES SUNDAY WHERE SOUTHWEST WINDS ARE EXPECTED TO INCREASE TO 20 TO 30 MPH WITH HIGHER GUSTS. ACROSS THE EASTERN PANHANDLES...WINDS ARE FORECAST TO BE SLIGHTLY WEAKER IN THE 15 TO 25 MPH RANGE. RELATIVE HUMIDITIES WILL FALL TO 5 TO 15 PERCENT AREA WIDE. A STRONG COLD FRONT WILL MOVE THROUGH ON MONDAY...WITH STRONG NORTH WINDS DEVELOPING BEHIND THE FRONT. RELATIVE HUMIDITIES EXPECTED TO STAY AROUND 20 PERCENT OR HIGHER DUE TO COOLER CONDITIONS...BUT THE WINDS WILL BE STRONG LEADING TO ELEVATED FIRE WEATHER CONDITIONS. ELEVATED FIRE WEATHER CONDITIONS MAY RETURN LATE NEXT WEEK AS TEMPERATURES WARM BACK UP AND SOUTH/SOUTHWEST WINDS RETURN. KB && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 51 88 49 91 48 / 10 0 0 0 5 BEAVER OK 51 86 51 92 50 / 10 0 0 0 5 BOISE CITY OK 48 85 49 89 46 / 5 0 0 0 5 BORGER TX 54 87 54 92 54 / 10 0 0 0 5 BOYS RANCH TX 48 88 48 92 47 / 10 0 0 0 0 CANYON TX 49 88 46 92 47 / 10 0 0 0 5 CLARENDON TX 54 88 53 93 52 / 10 0 0 0 5 DALHART TX 44 86 42 89 45 / 5 0 0 0 5 GUYMON OK 48 87 48 92 48 / 10 0 0 0 5 HEREFORD TX 47 86 47 91 46 / 5 0 0 0 5 LIPSCOMB TX 49 85 51 92 51 / 10 0 0 0 5 PAMPA TX 52 85 53 90 52 / 10 0 0 0 5 SHAMROCK TX 51 87 52 94 54 / 10 0 0 0 5 WELLINGTON TX 55 89 51 95 55 / 10 0 0 0 5 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...DALLAM...DEAF SMITH...HANSFORD...HARTLEY...HUTCHINSON...MOORE...OLDHAM... POTTER...RANDALL...SHERMAN. OK...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES: CIMARRON...TEXAS. && $$ 07/08
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1251 PM CDT FRI MAR 30 2012 .DISCUSSION...SEE 18Z TAF DISCUSSION. && .AVIATION...MAIN CONCERN IS HOW TO HANDLE POSSIBLE CONVECTION. MODEL CONSENSUS SHOWING SOMETHING IN THE KLRD AREA AFTER 00Z...BUT MODELS DIVERGE EVERYWHERE ELSE. IN SHORT...BELIEVE WITH S/W COMING ACROSS MEXICO LATER THIS AFTERNOON AND WITH DAYTIME HEATING...CONVECTION WILL DEVELOP LATE IN KLRD (AFTER 00Z) AND HAVE PUT A PROB30 THERE MAINLY AFTER 03Z. ELSEWHERE...CONFIDENCE IS NOT HIGH CONSIDERING THAT SFC/BOUNDARY LAYER WINDS ARE NOT THAT GREAT TO PUSH MCS ACROSS THAT FAR FOR THUNDER (COULD MAYBE SEE SHOWERS BUT NOT SURE). THUS...EXCEPT FOR VCTS AT KALI THIS AFTERNOON...ONLY CONVECTION MENTIONED IS IN KLRD. WILL HAVE VFR OUTSIDE OF THUNDER AT KLRD. ELSEWHERE...SKY AND VSBY CONDITIONS WILL DETERIORATE TO AT LEAST MVFR AT KCRP (CIGS) BY 10Z...IFR AT KALI (CIGS) BY 11Z...AND BOTTOMING OUT AT KVCT (1/2SM FG OVC002). CONDITIONS IMPROVE AFTER 15Z. WILL HAVE TO LOOK AT MESO MODELS MORE THOUGH FOR ZONE FORECAST...AND BRIEF NEXT SHIFT FOR 00Z TAF ISSUANCE SHOULD SHOWERS/THUNDER NEED TO BE ADDED FARTHER WEST. && .PREV DISCUSSION... /ISSUED 1044 AM CDT FRI MAR 30 2012/ DISCUSSION...ADJUSTED TEMPERATURES (ESPECIALLY HOURLY) BASED ON OBSERVATIONS AND TRENDS...BUT OVERALL DID LOWER SOME VALUES A DEGREE OR SO. ATMOSPHERE IS TRYING TO RE-LOAD AFTER LAST NIGHTS ACTIVITY BUT STILL PRETTY CAPPED. STILL A CHANCE FOR AFTERNOON CONVECTION MAINLY INLAND IF HEATING ALONG WITH SOME SURFACE BOUNDARIES/CONVERGENT AREAS DEVELOP AS AIRMASS REMAINS PRETTY UNSTABLE. WATER VAPOR IMAGERY SHOWING ANOTHER VERY WEAK IMPULSE GOING INTO NORTHERN MEXICO WHICH SHOULD IMPACT WESTERN AREAS LATE THIS AFTERNOON OR EARLY TONIGHT. ERGO...KEPT POPS IN FOR TONIGHT AS-IS...BUT DID ADJUST SOME INLAND POPS DOWN FROM WHAT WAS PREVIOUSLY FORECAST GIVEN THE SLIGHTLY DRIER AIRMASS TODAY AND MORE STABLE BEGINNINGS TO SOUTH TEXAS WEATHER THIS MORNING. UPDATED PRODUCTS OUT. MARINE...CONVECTION OFFSHORE HAS RESULTED IN LIGHT AND VARIABLE WINDS THIS MORNING. SHOULD RETURN TO ONSHORE FLOW THIS AFTERNOON AS SEA BREEZE GETS GOING. KEPT SOME CONVECTION IN FOR LATER THIS AFTERNOON BUT LIKELY ACTIVITY WILL REMAIN INLAND. NO CHANGES TO LATTER PERIODS YET. PREV DISCUSSION... /ISSUED 709 AM CDT FRI MAR 30 2012/ DISCUSSION...SEE AVIATION SECTION FOR 12Z TAF DISCUSSION. AVIATION...CONDITIONS AT KVCT WILL REMAIN AT LIFR THROUGH 15Z BEFORE GRADUALLY IMPROVING DURING THE MID TO LATE MORNING. OTHERWISE...VFR CONDITIONS WILL PREVAIL AT OTHER TAF SITES ACROSS SOUTH TX WITH A MID AND HIGH LEVEL DECK OF CLOUDS. A REPEAT OF LATE AFTERNOON SHRA/TSRA ACROSS THE REGION IS POSSIBLE...BUT NOT EXPLICITLY MENTIONED IN TAFS DUE TO TIMING CONCERNS. A VERY UNSTABLE AIRMASS WILL BE IN PLACE TODAY WHERE AFTERNOON SCATTERED CONVECTION DEVELOPMENT CAN BE INITIATED ON THE SEA BREEZE BOUNDARY...PARTICULARLY ACROSS THE EASTERN COASTAL PLAINS AND BRUSH COUNTRY AFFECTING SITES SUCH AS KCOT AND KALI BETWEEN 19-23Z. MVFR CEILINGS ARE EXPECTED TO MOVE BACK INTO THE COASTAL PLAINS BY 03Z SATURDAY. LOOKING OUT WEST...A COMPLEX OF THUNDERSTORMS ACROSS MEX ARE EXPECTED TO AFFECT LRD LATER THIS EVENING TOWARD MIDNIGHT. THIS SYSTEM IS EXPECTED TO GENERALLY MOVE SE ACROSS PORTIONS OF WEBB AND DUVAL COUNTIES. PREV DISCUSSION... /ISSUED 446 AM CDT FRI MAR 30 2012/ SHORT TERM (TODAY THROUGH SATURDAY)...REMNANT MCV IS APPARENT ON SATELLITE IMAGERY OVER THE WESTERN GULF IN ASSOCIATION WITH DECAYING CONVECTION THAT LIFTED FROM THE RGV AND TAMAULIPAS INTO THE OFFSHORE WATERS. WEAK SUBSIDENCE WILL TAKE PLACE THIS MORNING IN THE WAKE OF THE MCV. ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE AS THE MORNING PROGRESSES INTO AFTERNOON. MODELS SHOW THIS VERY UNSTABLE AIRMASS TO REMAIN OVER THE REGION TODAY. FORECAST INSTABILITY FIELDS SHOW CAPE FROM 3500-4000 J/KG OVER THE INLAND COASTAL PLAINS AND BRUSH COUNTRY THIS AFTERNOON WITH LIFTED INDEX VALUES AROUND -10 TO -12 DEGREES WITH LIMITED CONVECTIVE INHIBITION. RAISED POPS TO HIGH END CHANCES OF THUNDERSTORMS BETWEEN THE PARALLELING HIGHWAY 16 AND HIGHWAY 281 CORRIDOR THIS AFTERNOON. POTENTIAL FOR ISOLATED STRONG TO SEVERE THUNDERSTORMS POSSIBLE AGAIN THIS AFTERNOON INTO THE EARLY EVENING AS SEABREEZE PUSHES WESTWARD. TURNING THE FOCUS OUT WEST TONIGHT...GFS MODEL INDICATES A STRONG VORT LOBE FORECAST TO MOVE TOWARD THE NUEVO LEON/COAHUILA/TAMAULIPAS MEXICAN TRI- STATE REGION FRI NIGHT WITH GOOD PVA...INSTABILITY...AND MOISTURE TO EXIST FOR MCS FEATURE POSSIBLY DEVELOPING ALONG RIO GRANDE WITH CORFIDI VECTORS SUGGESTING A TRACK TO THE SOUTHWEST THROUGH THE NIGHT. HOWEVER...ECMWF...TEXAS TECH WRF AND HRRR NOT AS ROBUST WITH THIS MCS POTENTIAL. PAINTED 30 TO 50 PERCENT CHANCES OF SHOWERS AND THUNDERSTORMS MAINLY WEST OF HIGHWAY 281 DURING THE NOCTURNAL HOURS WHILE STRATIFYING POPS TO THE LOWER SIDE TOWARD THE COAST. QUIETER WEATHER...WITH MAINLY ISOLATED TO WIDELY SCATTERED CONVECTION ANTICIPATED SATURDAY IN THE WAKE OF A MID LEVEL SHORT- WAVE TROF WITH PWATS TRENDING SLIGHTLY LOWER WITH DRIER AIR STARTING TO WORK INTO THE REGION WITH CAPES STILL REMAINING ABOVE 2500 J/KG. ABOVE NORMAL TEMPERATURES THROUGH THE SHORT TERM PERIOD WITH BREEZY LATE MORNING AND AFTERNOON WINDS. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY NIGHT)...DESPITE WEAKNESS IN FLOW ALOFT STILL EXISTING SATURDAY NIGHT...MODELS SUGGEST MOISTURE MAY NOT BE AS IMPRESSIVE AS THE LAST FEW DAYS. PWATS VALUES MAY DROP BELOW 1 INCH BY 12Z SUNDAY SO HAVE OPTED TO LEAVE THUNDERSTORM CHANCES OUT OF THE FORECAST AT THIS TIME. ANOTHER WARM DAY CAN EXPECTED ON SUNDAY ACROSS SOUTH TEXAS WITH LOWER/MID 90S IN THE BRUSH COUNTRY TO LOWER 80S ALONG THE COAST. GUIDANCE HAS BEEN TOO WARM OUT WEST LATELY...AND WITH RECENT RAINS OVER THOSE LOCATIONS TOOK A FEW DEGREES OFF MOS TEMPS. FOR EARLY NEXT WEEK... TIMING OF COLD FRONT WILL REMAIN THE MAIN FORECAST CHALLENGE. MODELS NOW OFFERING UP A CLOSED LOW SOLUTION OVER THE CENTRAL PLAINS STATES MONDAY AND TUESDAY. COLD FRONT TIMING HAS BEEN SLOWED DOWN WITH THE 00Z RUNS AND HAVE INCORPORATED THIS INTO THE FORECAST...WITH THE GFS BEING QUICKER THAN THE EURO WITH FROPA OFF THE COAST. FORECAST CONFIDENCE IS NOT THE HIGHEST IN TIMING OF THE FRONT AND SUSPECT FURTHER FINE TUNING WILL BE NEEDED. FOR NOW WILL PLACE THE FRONT ROUGHLY THROUGH THE WESTERN HALF OF THE REGION BY 12Z TUESDAY AND OFF THE COAST BY 18Z. ANOTHER DAY OF WARM TEMPS IN ADVANCE OF THE FRONT WILL OCCUR ON MONDAY. INCLUDED SOME LOW END THUNDERSTORM CHANCES MONDAY AND MONDAY NIGHT AS LIFT/INSTABILITY INCREASES AHEAD OF UPPER TROUGH/FRONT. TEMPS WILL BE KNOCKED DOWN BY 5 TO 10 DEGREES FOR TUESDAY AND WEDNESDAY...WITH LOWER 80S OUT WEST TO UPPER 70S ALONG THE COAST. AS FOR THE LATTER HALF OF THE WEEK...THERE WILL BE A SLOW RETURN IN MOISTURE AS NORTHEAST-EASTERLY FLOW AT THE SURFACE BECOMES SOUTHEAST LATE THURSDAY. RIDGING ALOFT WILL LEAD TO PARTLY CLOUDY SKIES IN THE AFTERNOON...QUIET WEATHER AND A GRADUAL WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 87 68 86 68 87 / 30 30 20 10 10 VICTORIA 83 67 84 68 85 / 30 20 20 10 10 LAREDO 91 69 93 68 94 / 20 50 20 10 10 ALICE 89 66 89 68 89 / 30 40 30 10 10 ROCKPORT 81 69 80 70 80 / 30 20 20 10 10 COTULLA 87 65 90 67 92 / 30 50 20 10 10 KINGSVILLE 88 68 88 67 88 / 30 30 20 10 10 NAVY CORPUS 82 68 82 69 82 / 30 20 20 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM/AVIATION RH/79...LONG TERM
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1226 PM CDT FRI MAR 30 2012 .UPDATE... PATCHY MORNING FOG HAS SINCE DISSIPATED AND LOW CLOUDS CONTINUE TO LIFT AND SCATTER OUT LATE THIS MORNING. HAVE UPDATED THE FORECAST TO REFLECT THESE CHANGES AND ALSO TO SLIGHTLY ADJUST POPS FOR THIS AFTERNOON AND EVENING. HUNG ONTO AN ISOLATED THUNDERSTORM MENTION ACROSS MOST OF THE AREA LATE AFTERNOON TROUGH EARLY EVENING...BUT REMOVED FROM THE FAR WEST WHERE LOW-LEVEL MOISTURE WILL CONTINUE TO MIX OUT. ELSEWHERE...THUNDERSTORM CHANCES LOOK VERY SLIM AND EXPECT ANY CONVECTION TO BE VERY ISOLATED IF IT DEVELOPS. LOW-LEVEL MOISTURE /AND ASSOCIATED INSTABILITY/ WILL REMAIN IN PLACE ACROSS EASTERN AND CENTRAL AREAS DUE TO CIRCULATION AROUND SURFACE LOW OVER THE ROLLING PLAINS...AND DAYTIME HEATING WILL HELP TO ERODE THE CAP BY LATE IN THE DAY. HOWEVER...AT LEAST SOME WEAK CAPPING IS EXPECTED TO REMAIN AND NOT MUCH FORCING WILL BE AVAILABLE TO TRIGGER ANYTHING. FORCING FROM MID-LEVEL SHORTWAVE CURRENTLY PASSING OVER THE AREA WILL SHIFT EAST BY LATER IN THE DAY. WATER VAPOR IMAGERY AND RUC ANALYSIS DATA DO SHOW A WEAK RIPPLE OVER SOUTH CENTRAL CO...WHICH COULD PROVIDE SOME WEAK FORCING BUT IT MAY BE TRUMPED BY SUBSIDENCE IN WAKE OF STRONGER LEAD WAVE. VERY WEAK UPSLOPE SURFACE FLOW WILL DEVELOP NORTH OF THE SURFACE LOW...BUT IT WILL BE WEAK WITH NO BOUNDARIES FORESEEN TO ENHANCE LOW-LEVEL CONVERGENCE. THUS...CHANCES OF ANYTHING DEVELOPING ARE LOW...BUT CANNOT RULE OUT AN ISOLATED STORM OR TWO AS SOME SHORT-RANGE MODELS SUCH AS THE RUC AND WRF-NMM CONTINUE TO INDICATE LATE IN THE DAY AROUND PEAK HEATING. IF SOMETHING DOES DEVELOP...IT COULD VERY WELL BE STRONG TO SEVERE AS MLCAPES WILL BE IN THE 1500-2000 J/KG RANGE WITH DEEP-LAYER SHEAR AROUND 25-35 KTS...POSSIBLY 40 KTS EARLY THIS EVENING IN THE NORTHEAST. LARGE HAIL WOULD BE THE MAIN HAZARD...WITH STRONG WINDS ALSO POSSIBLE. KB && .PREV DISCUSSION... /ISSUED 1219 PM CDT FRI MAR 30 2012/ AVIATION... WEAK SHORTWAVE WILL MOVE EAST OF THE PANHANDLES THIS AFTERNOON. SUBSIDENCE BEHIND WAVE SHOULD PRECLUDE THUNDERSTORM DEVELOPMENT AT TAF SITES. LIGHT SOUTH SOUTHEAST LOW LEVEL FLOW COULD BRING LOW CLOUDS BACK INTO THE PANHANDLES TONIGHT BUT CURRENT THINKING IS CLOUDS WILL BE CONFINED TO THE EASTERN PANHANDLES AND NOT AFFECT THE TERMINALS. OVERALL...VFR CONDITIONS TO PREVAIL ACROSS THE TAF SITES THROUGH 31/18Z. PREV DISCUSSION... /ISSUED 708 AM CDT FRI MAR 30 2012/ AVIATION... FOR THE 12Z TAFS...LOW CLOUDS HAVE MOVED ACROSS THE TERMINALS WITH CONDITIONS FLUCTUATING BETWEEN MVFR AND IFR. EXPECT LOW CLOUDS TO DISSIPATE LATER THIS MORNING WITH VFR CONDITIONS RETURNING. MEANWHILE A COLD FRONT HAS PUSHED THROUGH THE TERMINALS WITH NORTHWEST WINDS BEHIND THE FRONT WHILE OUTFLOW FROM ONGOING TSRA IN OKLAHOMA HAS KEPT SURFACE WINDS OUT OF THE SOUTHEAST AT THE KAMA TERMINAL. WINDS AT KAMA WILL VEER TO NORTH BY 15Z. A SURFACE TROUGH DIVING SOUTHEAST INTO CENTRAL TEXAS LATER TODAY WILL KEEP WIND SPEEDS LIGHT /AT OR UNDER 10 KTS/ THROUGH THE FORECAST PERIOD. A WEAK SHORTWAVE TROUGH WILL CROSS THE AREA LATER TODAY WHICH CAN GENERATE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING. HOWEVER LIFT ASSOCIATED WITH THIS SYSTEM IS PRETTY WEAK AND THEREFORE CHANCES FOR TSRA TO IMPACT ANY OF THE TERMINALS IS PRETTY SLIM SO LEFT OUT EVEN CB REMARKS IN THE TAFS. LOW-LEVEL MOISTURE MAY INCREASE AGAIN LATE TONIGHT/EARLY SATURDAY BUT HAVE KEPT CONDITIONS VFR FOR NOW AS CONFIDENCE IS TOO LOW TO MENTION DETERIORATING CIGS/VISBYS WITH FOG. CLK PREV DISCUSSION... /ISSUED 634 AM CDT FRI MAR 30 2012/ DISCUSSION... SFC COLD FRONT HAS PUSHED S OF FCST AREA. LOW CLOUDS AND PATCHY FOG HAVE DEVELOPED OVER THE AREA...AND THIS IS ACCOUNTED FOR IN GRIDS. EXPECT THE FOG AND LOW CLOUDS TO ERODE SOMETIME THIS MORNING WITH PTCLDY SKIES FOR AFTERNOON. RETAINED A LESS THAN 20 PERCENT CHANCE OF TSTMS OVER MOST OF AREA THIS AFTERNOON...AND SRN HALF OF TX PNHDL THIS EVENING. IT APPEARS MAIN FORCING WILL BE OUT OF PHASE WITH DAYTIME HEATING SO IF STORMS FORM THEY SHOULD BE RATHER ISOLATED. WELL ABOVE NORMAL TEMPS ARE LIKELY AGAIN FOR THE WEEKEND. ALL MODELS NOW SUGGEST NEXT VIGOROUS UPPER LEVEL LOW PRESSURE SYSTEM WILL BE EVEN SLOWER TO ARRIVE AND MOVE ACROSS THE AREA...AND WILL ALSO HAVE MORE OF A CLOSED OFF LOOK AS OPPOSED TO AN OPEN WAVE. THIS EXPECTED SLOWER MOVEMENT ALSO MEANS WIND MACHINE WILL NOT CRANK UP IN EARNEST ON SUNDAY AS EARLIER THOUGHT. IN FACT MOS WINDS FOR THAT TIME PERIOD ARE MUCH LESS. THE WINDIER DAY APPEARS TO BE MONDAY INTO TUESDAY...AND HAVE ADJUSTED THIS TIMING IN THE GRIDS. SPEEDS COULD APPROACH ADVISORY LEVELS SOMETIME MONDAY. DUE TO SLOWER AND FURTHER S PROJECTED PATH OF THIS NEXT UPPER LOW... MOST MODELS...INCLUDING GFS AND ECMWF...PAINT WRAPAROUND QPF ACROSS THE AREA LATE MONDAY AFTERNOON INTO TUESDAY MORNING. HAVE INTRODUCED SLGT CHC POPS FOR RAINSHOWERS MONDAY AFTERNOON ACROSS NWRN ZONES... THEN SPREAD THEM S AND E TO INCLUDE ALL OF FCST AREA MONDAY NIGHT. KEPT TUESDAY DRY FOR NOW BUT IF THIS STORM SYSTEM ENDS UP EVEN SLOWER TO MOVE OUT OF THE AREA...THEN POPS MAY BE NEEDED FOR PART OF THE AREA ON TUESDAY. DRY WEATHER SEEN FROM TUE NIGHT ONWARD THRU REST OF EXTENDED PERIODS. ANDRADE FIRE WEATHER... ELEVATED FIRE WEATHER CONDITIONS WILL BE POSSIBLE ACROSS WESTERN AND CENTRAL SECTIONS OF THE OK AND TX PNHDLS SATURDAY DUE TO SOUTH TO SOUTHWEST WINDS OF 10 TO 20 MPH WITH SOME HIGHER GUSTS ALONG WITH FORECAST MINIMUM RELATIVE HUMIDITY VALUES AROUND 15 PERCENT. CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED ACROSS THE PNHDLS ON SUNDAY DUE TO STRONG SW WINDS AND LOW RELATIVE HUMIDITY VALUES OF 5 TO 15 PERCENT. ELEVATED FIRE WEATHER CONDITIONS ARE ALSO ANTICIPATED ON MONDAY ACROSS MOST OF THE AREA DUE TO STRONG WINDS AND MINIMUM RELATIVE HUMIDITY VALUES AROUND 20 PERCENT. ANDRADE && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 07/08
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1044 AM CDT FRI MAR 30 2012 .DISCUSSION...ADJUSTED TEMPERATURES (ESPECIALLY HOURLY) BASED ON OBSERVATIONS AND TRENDS...BUT OVERALL DID LOWER SOME VALUES A DEGREE OR SO. ATMOSPHERE IS TRYING TO RE-LOAD AFTER LAST NIGHTS ACTIVITY BUT STILL PRETTY CAPPED. STILL A CHANCE FOR AFTERNOON CONVECTION MAINLY INLAND IF HEATING ALONG WITH SOME SURFACE BOUNDARIES/CONVERGENT AREAS DEVELOP AS AIRMASS REMAINS PRETTY UNSTABLE. WATER VAPOR IMAGERY SHOWING ANOTHER VERY WEAK IMPULSE GOING INTO NORTHERN MEXICO WHICH SHOULD IMPACT WESTERN AREAS LATE THIS AFTERNOON OR EARLY TONIGHT. ERGO...KEPT POPS IN FOR TONIGHT AS-IS...BUT DID ADJUST SOME INLAND POPS DOWN FROM WHAT WAS PREVIOUSLY FORECAST GIVEN THE SLIGHTLY DRIER AIRMASS TODAY AND MORE STABLE BEGINNINGS TO SOUTH TEXAS WEATHER THIS MORNING. UPDATED PRODUCTS OUT. && .MARINE...CONVECTION OFFSHORE HAS RESULTED IN LIGHT AND VARIABLE WINDS THIS MORNING. SHOULD RETURN TO ONSHORE FLOW THIS AFTERNOON AS SEA BREEZE GETS GOING. KEPT SOME CONVECTION IN FOR LATER THIS AFTERNOON BUT LIKELY ACTIVITY WILL REMAIN INLAND. NO CHANGES TO LATTER PERIODS YET. && .PREV DISCUSSION... /ISSUED 709 AM CDT FRI MAR 30 2012/ DISCUSSION...SEE AVIATION SECTION FOR 12Z TAF DISCUSSION. AVIATION...CONDITIONS AT KVCT WILL REMAIN AT LIFR THROUGH 15Z BEFORE GRADUALLY IMPROVING DURING THE MID TO LATE MORNING. OTHERWISE...VFR CONDITIONS WILL PREVAIL AT OTHER TAF SITES ACROSS SOUTH TX WITH A MID AND HIGH LEVEL DECK OF CLOUDS. A REPEAT OF LATE AFTERNOON SHRA/TSRA ACROSS THE REGION IS POSSIBLE...BUT NOT EXPLICITLY MENTIONED IN TAFS DUE TO TIMING CONCERNS. A VERY UNSTABLE AIRMASS WILL BE IN PLACE TODAY WHERE AFTERNOON SCATTERED CONVECTION DEVELOPMENT CAN BE INITIATED ON THE SEA BREEZE BOUNDARY...PARTICULARLY ACROSS THE EASTERN COASTAL PLAINS AND BRUSH COUNTRY AFFECTING SITES SUCH AS KCOT AND KALI BETWEEN 19-23Z. MVFR CEILINGS ARE EXPECTED TO MOVE BACK INTO THE COASTAL PLAINS BY 03Z SATURDAY. LOOKING OUT WEST...A COMPLEX OF THUNDERSTORMS ACROSS MEX ARE EXPECTED TO AFFECT LRD LATER THIS EVENING TOWARD MIDNIGHT. THIS SYSTEM IS EXPECTED TO GENERALLY MOVE SE ACROSS PORTIONS OF WEBB AND DUVAL COUNTIES. PREV DISCUSSION... /ISSUED 446 AM CDT FRI MAR 30 2012/ SHORT TERM (TODAY THROUGH SATURDAY)...REMNANT MCV IS APPARENT ON SATELLITE IMAGERY OVER THE WESTERN GULF IN ASSOCIATION WITH DECAYING CONVECTION THAT LIFTED FROM THE RGV AND TAMAULIPAS INTO THE OFFSHORE WATERS. WEAK SUBSIDENCE WILL TAKE PLACE THIS MORNING IN THE WAKE OF THE MCV. ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE AS THE MORNING PROGRESSES INTO AFTERNOON. MODELS SHOW THIS VERY UNSTABLE AIRMASS TO REMAIN OVER THE REGION TODAY. FORECAST INSTABILITY FIELDS SHOW CAPE FROM 3500-4000 J/KG OVER THE INLAND COASTAL PLAINS AND BRUSH COUNTRY THIS AFTERNOON WITH LIFTED INDEX VALUES AROUND -10 TO -12 DEGREES WITH LIMITED CONVECTIVE INHIBITION. RAISED POPS TO HIGH END CHANCES OF THUNDERSTORMS BETWEEN THE PARALLELING HIGHWAY 16 AND HIGHWAY 281 CORRIDOR THIS AFTERNOON. POTENTIAL FOR ISOLATED STRONG TO SEVERE THUNDERSTORMS POSSIBLE AGAIN THIS AFTERNOON INTO THE EARLY EVENING AS SEABREEZE PUSHES WESTWARD. TURNING THE FOCUS OUT WEST TONIGHT...GFS MODEL INDICATES A STRONG VORT LOBE FORECAST TO MOVE TOWARD THE NUEVO LEON/COAHUILA/TAMAULIPAS MEXICAN TRI- STATE REGION FRI NIGHT WITH GOOD PVA...INSTABILITY...AND MOISTURE TO EXIST FOR MCS FEATURE POSSIBLY DEVELOPING ALONG RIO GRANDE WITH CORFIDI VECTORS SUGGESTING A TRACK TO THE SOUTHWEST THROUGH THE NIGHT. HOWEVER...ECMWF...TEXAS TECH WRF AND HRRR NOT AS ROBUST WITH THIS MCS POTENTIAL. PAINTED 30 TO 50 PERCENT CHANCES OF SHOWERS AND THUNDERSTORMS MAINLY WEST OF HIGHWAY 281 DURING THE NOCTURNAL HOURS WHILE STRATIFYING POPS TO THE LOWER SIDE TOWARD THE COAST. QUIETER WEATHER...WITH MAINLY ISOLATED TO WIDELY SCATTERED CONVECTION ANTICIPATED SATURDAY IN THE WAKE OF A MID LEVEL SHORT- WAVE TROF WITH PWATS TRENDING SLIGHTLY LOWER WITH DRIER AIR STARTING TO WORK INTO THE REGION WITH CAPES STILL REMAINING ABOVE 2500 J/KG. ABOVE NORMAL TEMPERATURES THROUGH THE SHORT TERM PERIOD WITH BREEZY LATE MORNING AND AFTERNOON WINDS. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY NIGHT)...DESPITE WEAKNESS IN FLOW ALOFT STILL EXISTING SATURDAY NIGHT...MODELS SUGGEST MOISTURE MAY NOT BE AS IMPRESSIVE AS THE LAST FEW DAYS. PWATS VALUES MAY DROP BELOW 1 INCH BY 12Z SUNDAY SO HAVE OPTED TO LEAVE THUNDERSTORM CHANCES OUT OF THE FORECAST AT THIS TIME. ANOTHER WARM DAY CAN EXPECTED ON SUNDAY ACROSS SOUTH TEXAS WITH LOWER/MID 90S IN THE BRUSH COUNTRY TO LOWER 80S ALONG THE COAST. GUIDANCE HAS BEEN TOO WARM OUT WEST LATELY...AND WITH RECENT RAINS OVER THOSE LOCATIONS TOOK A FEW DEGREES OFF MOS TEMPS. FOR EARLY NEXT WEEK... TIMING OF COLD FRONT WILL REMAIN THE MAIN FORECAST CHALLENGE. MODELS NOW OFFERING UP A CLOSED LOW SOLUTION OVER THE CENTRAL PLAINS STATES MONDAY AND TUESDAY. COLD FRONT TIMING HAS BEEN SLOWED DOWN WITH THE 00Z RUNS AND HAVE INCORPORATED THIS INTO THE FORECAST...WITH THE GFS BEING QUICKER THAN THE EURO WITH FROPA OFF THE COAST. FORECAST CONFIDENCE IS NOT THE HIGHEST IN TIMING OF THE FRONT AND SUSPECT FURTHER FINE TUNING WILL BE NEEDED. FOR NOW WILL PLACE THE FRONT ROUGHLY THROUGH THE WESTERN HALF OF THE REGION BY 12Z TUESDAY AND OFF THE COAST BY 18Z. ANOTHER DAY OF WARM TEMPS IN ADVANCE OF THE FRONT WILL OCCUR ON MONDAY. INCLUDED SOME LOW END THUNDERSTORM CHANCES MONDAY AND MONDAY NIGHT AS LIFT/INSTABILITY INCREASES AHEAD OF UPPER TROUGH/FRONT. TEMPS WILL BE KNOCKED DOWN BY 5 TO 10 DEGREES FOR TUESDAY AND WEDNESDAY...WITH LOWER 80S OUT WEST TO UPPER 70S ALONG THE COAST. AS FOR THE LATTER HALF OF THE WEEK...THERE WILL BE A SLOW RETURN IN MOISTURE AS NORTHEAST-EASTERLY FLOW AT THE SURFACE BECOMES SOUTHEAST LATE THURSDAY. RIDGING ALOFT WILL LEAD TO PARTLY CLOUDY SKIES IN THE AFTERNOON...QUIET WEATHER AND A GRADUAL WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 87 68 86 68 87 / 30 30 20 10 10 VICTORIA 83 67 84 68 85 / 30 20 20 10 10 LAREDO 91 69 93 68 94 / 20 50 20 10 10 ALICE 89 66 89 68 89 / 30 40 30 10 10 ROCKPORT 81 69 80 70 80 / 30 20 20 10 10 COTULLA 87 65 90 67 92 / 30 50 20 10 10 KINGSVILLE 88 68 88 67 88 / 30 30 20 10 10 NAVY CORPUS 82 68 82 69 82 / 30 20 20 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM RH/79...LONG TERM
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
709 AM CDT FRI MAR 30 2012 .DISCUSSION...SEE AVIATION SECTION FOR 12Z TAF DISCUSSION. && .AVIATION...CONDITIONS AT KVCT WILL REMAIN AT LIFR THROUGH 15Z BEFORE GRADUALLY IMPROVING DURING THE MID TO LATE MORNING. OTHERWISE...VFR CONDITIONS WILL PREVAIL AT OTHER TAF SITES ACROSS SOUTH TX WITH A MID AND HIGH LEVEL DECK OF CLOUDS. A REPEAT OF LATE AFTERNOON SHRA/TSRA ACROSS THE REGION IS POSSIBLE...BUT NOT EXPLICITLY MENTIONED IN TAFS DUE TO TIMING CONCERNS. A VERY UNSTABLE AIRMASS WILL BE IN PLACE TODAY WHERE AFTERNOON SCATTERED CONVECTION DEVELOPMENT CAN BE INITIATED ON THE SEA BREEZE BOUNDARY...PARTICULARLY ACROSS THE EASTERN COASTAL PLAINS AND BRUSH COUNTRY AFFECTING SITES SUCH AS KCOT AND KALI BETWEEN 19-23Z. MVFR CEILINGS ARE EXPECTED TO MOVE BACK INTO THE COASTAL PLAINS BY 03Z SATURDAY. LOOKING OUT WEST...A COMPLEX OF THUNDERSTORMS ACROSS MEX ARE EXPECTED TO AFFECT LRD LATER THIS EVENING TOWARD MIDNIGHT. THIS SYSTEM IS EXPECTED TO GENERALLY MOVE SE ACROSS PORTIONS OF WEBB AND DUVAL COUNTIES. && .PREV DISCUSSION... /ISSUED 446 AM CDT FRI MAR 30 2012/ SHORT TERM (TODAY THROUGH SATURDAY)...REMNANT MCV IS APPARENT ON SATELLITE IMAGERY OVER THE WESTERN GULF IN ASSOCIATION WITH DECAYING CONVECTION THAT LIFTED FROM THE RGV AND TAMAULIPAS INTO THE OFFSHORE WATERS. WEAK SUBSIDENCE WILL TAKE PLACE THIS MORNING IN THE WAKE OF THE MCV. ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE AS THE MORNING PROGRESSES INTO AFTERNOON. MODELS SHOW THIS VERY UNSTABLE AIRMASS TO REMAIN OVER THE REGION TODAY. FORECAST INSTABILITY FIELDS SHOW CAPE FROM 3500-4000 J/KG OVER THE INLAND COASTAL PLAINS AND BRUSH COUNTRY THIS AFTERNOON WITH LIFTED INDEX VALUES AROUND -10 TO -12 DEGREES WITH LIMITED CONVECTIVE INHIBITION. RAISED POPS TO HIGH END CHANCES OF THUNDERSTORMS BETWEEN THE PARALLELING HIGHWAY 16 AND HIGHWAY 281 CORRIDOR THIS AFTERNOON. POTENTIAL FOR ISOLATED STRONG TO SEVERE THUNDERSTORMS POSSIBLE AGAIN THIS AFTERNOON INTO THE EARLY EVENING AS SEABREEZE PUSHES WESTWARD. TURNING THE FOCUS OUT WEST TONIGHT...GFS MODEL INDICATES A STRONG VORT LOBE FORECAST TO MOVE TOWARD THE NUEVO LEON/COAHUILA/TAMAULIPAS MEXICAN TRI- STATE REGION FRI NIGHT WITH GOOD PVA...INSTABILITY...AND MOISTURE TO EXIST FOR MCS FEATURE POSSIBLY DEVELOPING ALONG RIO GRANDE WITH CORFIDI VECTORS SUGGESTING A TRACK TO THE SOUTHWEST THROUGH THE NIGHT. HOWEVER...ECMWF...TEXAS TECH WRF AND HRRR NOT AS ROBUST WITH THIS MCS POTENTIAL. PAINTED 30 TO 50 PERCENT CHANCES OF SHOWERS AND THUNDERSTORMS MAINLY WEST OF HIGHWAY 281 DURING THE NOCTURNAL HOURS WHILE STRATIFYING POPS TO THE LOWER SIDE TOWARD THE COAST. QUIETER WEATHER...WITH MAINLY ISOLATED TO WIDELY SCATTERED CONVECTION ANTICIPATED SATURDAY IN THE WAKE OF A MID LEVEL SHORT- WAVE TROF WITH PWATS TRENDING SLIGHTLY LOWER WITH DRIER AIR STARTING TO WORK INTO THE REGION WITH CAPES STILL REMAINING ABOVE 2500 J/KG. ABOVE NORMAL TEMPERATURES THROUGH THE SHORT TERM PERIOD WITH BREEZY LATE MORNING AND AFTERNOON WINDS. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY NIGHT)...DESPITE WEAKNESS IN FLOW ALOFT STILL EXISTING SATURDAY NIGHT...MODELS SUGGEST MOISTURE MAY NOT BE AS IMPRESSIVE AS THE LAST FEW DAYS. PWATS VALUES MAY DROP BELOW 1 INCH BY 12Z SUNDAY SO HAVE OPTED TO LEAVE THUNDERSTORM CHANCES OUT OF THE FORECAST AT THIS TIME. ANOTHER WARM DAY CAN EXPECTED ON SUNDAY ACROSS SOUTH TEXAS WITH LOWER/MID 90S IN THE BRUSH COUNTRY TO LOWER 80S ALONG THE COAST. GUIDANCE HAS BEEN TOO WARM OUT WEST LATELY...AND WITH RECENT RAINS OVER THOSE LOCATIONS TOOK A FEW DEGREES OFF MOS TEMPS. FOR EARLY NEXT WEEK... TIMING OF COLD FRONT WILL REMAIN THE MAIN FORECAST CHALLENGE. MODELS NOW OFFERING UP A CLOSED LOW SOLUTION OVER THE CENTRAL PLAINS STATES MONDAY AND TUESDAY. COLD FRONT TIMING HAS BEEN SLOWED DOWN WITH THE 00Z RUNS AND HAVE INCORPORATED THIS INTO THE FORECAST...WITH THE GFS BEING QUICKER THAN THE EURO WITH FROPA OFF THE COAST. FORECAST CONFIDENCE IS NOT THE HIGHEST IN TIMING OF THE FRONT AND SUSPECT FURTHER FINE TUNING WILL BE NEEDED. FOR NOW WILL PLACE THE FRONT ROUGHLY THROUGH THE WESTERN HALF OF THE REGION BY 12Z TUESDAY AND OFF THE COAST BY 18Z. ANOTHER DAY OF WARM TEMPS IN ADVANCE OF THE FRONT WILL OCCUR ON MONDAY. INCLUDED SOME LOW END THUNDERSTORM CHANCES MONDAY AND MONDAY NIGHT AS LIFT/INSTABILITY INCREASES AHEAD OF UPPER TROUGH/FRONT. TEMPS WILL BE KNOCKED DOWN BY 5 TO 10 DEGREES FOR TUESDAY AND WEDNESDAY...WITH LOWER 80S OUT WEST TO UPPER 70S ALONG THE COAST. AS FOR THE LATTER HALF OF THE WEEK...THERE WILL BE A SLOW RETURN IN MOISTURE AS NORTHEAST-EASTERLY FLOW AT THE SURFACE BECOMES SOUTHEAST LATE THURSDAY. RIDGING ALOFT WILL LEAD TO PARTLY CLOUDY SKIES IN THE AFTERNOON...QUIET WEATHER AND A GRADUAL WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 86 68 86 68 87 / 30 30 20 10 10 VICTORIA 84 67 84 68 85 / 30 20 20 10 10 LAREDO 92 69 93 68 94 / 20 50 20 10 10 ALICE 89 66 89 68 89 / 50 40 30 10 10 ROCKPORT 82 69 80 70 80 / 30 20 20 10 10 COTULLA 87 65 90 67 92 / 30 50 20 10 10 KINGSVILLE 87 68 88 67 88 / 30 30 20 10 10 NAVY CORPUS 81 68 82 69 82 / 30 20 20 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ SC/70...SHORT TERM TB/78...LONG TERM
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
446 AM CDT FRI MAR 30 2012 .SHORT TERM (TODAY THROUGH SATURDAY)...REMNANT MCV IS APPARENT ON SATELLITE IMAGERY OVER THE WESTERN GULF IN ASSOCIATION WITH DECAYING CONVECTION THAT LIFTED FROM THE RGV AND TAMAULIPAS INTO THE OFFSHORE WATERS. WEAK SUBSIDENCE WILL TAKE PLACE THIS MORNING IN THE WAKE OF THE MCV. ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE AS THE MORNING PROGRESSES INTO AFTERNOON. MODELS SHOW THIS VERY UNSTABLE AIRMASS TO REMAIN OVER THE REGION TODAY. FORECAST INSTABILITY FIELDS SHOW CAPE FROM 3500-4000 J/KG OVER THE INLAND COASTAL PLAINS AND BRUSH COUNTRY THIS AFTERNOON WITH LIFTED INDEX VALUES AROUND -10 TO -12 DEGREES WITH LIMITED CONVECTIVE INHIBITION. RAISED POPS TO HIGH END CHANCES OF THUNDERSTORMS BETWEEN THE PARALLELING HIGHWAY 16 AND HIGHWAY 281 CORRIDOR THIS AFTERNOON. POTENTIAL FOR ISOLATED STRONG TO SEVERE THUNDERSTORMS POSSIBLE AGAIN THIS AFTERNOON INTO THE EARLY EVENING AS SEABREEZE PUSHES WESTWARD. TURNING THE FOCUS OUT WEST TONIGHT...GFS MODEL INDICATES A STRONG VORT LOBE FORECAST TO MOVE TOWARD THE NUEVO LEON/COAHUILA/TAMAULIPAS MEXICAN TRI- STATE REGION FRI NIGHT WITH GOOD PVA...INSTABILITY...AND MOISTURE TO EXIST FOR MCS FEATURE POSSIBLY DEVELOPING ALONG RIO GRANDE WITH CORFIDI VECTORS SUGGESTING A TRACK TO THE SOUTHWEST THROUGH THE NIGHT. HOWEVER...ECMWF...TEXAS TECH WRF AND HRRR NOT AS ROBUST WITH THIS MCS POTENTIAL. PAINTED 30 TO 50 PERCENT CHANCES OF SHOWERS AND THUNDERSTORMS MAINLY WEST OF HIGHWAY 281 DURING THE NOCTURNAL HOURS WHILE STRATIFYING POPS TO THE LOWER SIDE TOWARD THE COAST. QUIETER WEATHER...WITH MAINLY ISOLATED TO WIDELY SCATTERED CONVECTION ANTICIPATED SATURDAY IN THE WAKE OF A MID LEVEL SHORT- WAVE TROF WITH PWATS TRENDING SLIGHTLY LOWER WITH DRIER AIR STARTING TO WORK INTO THE REGION WITH CAPES STILL REMAINING ABOVE 2500 J/KG. ABOVE NORMAL TEMPERATURES THROUGH THE SHORT TERM PERIOD WITH BREEZY LATE MORNING AND AFTERNOON WINDS. && .LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY NIGHT)...DESPITE WEAKNESS IN FLOW ALOFT STILL EXISTING SATURDAY NIGHT...MODELS SUGGEST MOISTURE MAY NOT BE AS IMPRESSIVE AS THE LAST FEW DAYS. PWATS VALUES MAY DROP BELOW 1 INCH BY 12Z SUNDAY SO HAVE OPTED TO LEAVE THUNDERSTORM CHANCES OUT OF THE FORECAST AT THIS TIME. ANOTHER WARM DAY CAN EXPECTED ON SUNDAY ACROSS SOUTH TEXAS WITH LOWER/MID 90S IN THE BRUSH COUNTRY TO LOWER 80S ALONG THE COAST. GUIDANCE HAS BEEN TOO WARM OUT WEST LATELY...AND WITH RECENT RAINS OVER THOSE LOCATIONS TOOK A FEW DEGREES OFF MOS TEMPS. FOR EARLY NEXT WEEK... TIMING OF COLD FRONT WILL REMAIN THE MAIN FORECAST CHALLENGE. MODELS NOW OFFERING UP A CLOSED LOW SOLUTION OVER THE CENTRAL PLAINS STATES MONDAY AND TUESDAY. COLD FRONT TIMING HAS BEEN SLOWED DOWN WITH THE 00Z RUNS AND HAVE INCORPORATED THIS INTO THE FORECAST...WITH THE GFS BEING QUICKER THAN THE EURO WITH FROPA OFF THE COAST. FORECAST CONFIDENCE IS NOT THE HIGHEST IN TIMING OF THE FRONT AND SUSPECT FURTHER FINE TUNING WILL BE NEEDED. FOR NOW WILL PLACE THE FRONT ROUGHLY THROUGH THE WESTERN HALF OF THE REGION BY 12Z TUESDAY AND OFF THE COAST BY 18Z. ANOTHER DAY OF WARM TEMPS IN ADVANCE OF THE FRONT WILL OCCUR ON MONDAY. INCLUDED SOME LOW END THUNDERSTORM CHANCES MONDAY AND MONDAY NIGHT AS LIFT/INSTABILITY INCREASES AHEAD OF UPPER TROUGH/FRONT. TEMPS WILL BE KNOCKED DOWN BY 5 TO 10 DEGREES FOR TUESDAY AND WEDNESDAY...WITH LOWER 80S OUT WEST TO UPPER 70S ALONG THE COAST. AS FOR THE LATTER HALF OF THE WEEK...THERE WILL BE A SLOW RETURN IN MOISTURE AS NORTHEAST-EASTERLY FLOW AT THE SURFACE BECOMES SOUTHEAST LATE THURSDAY. RIDGING ALOFT WILL LEAD TO PARTLY CLOUDY SKIES IN THE AFTERNOON...QUIET WEATHER AND A GRADUAL WARMING TREND. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 86 68 86 68 87 / 30 30 20 10 10 VICTORIA 84 67 84 68 85 / 30 20 20 10 10 LAREDO 92 69 93 68 94 / 20 50 20 10 10 ALICE 89 66 89 68 89 / 50 40 30 10 10 ROCKPORT 82 69 80 70 80 / 30 20 20 10 10 COTULLA 87 65 90 67 92 / 30 50 20 10 10 KINGSVILLE 87 68 88 67 88 / 30 30 20 10 10 NAVY CORPUS 81 68 82 69 82 / 30 20 20 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ SC/70...SHORT TERM TB/78...LONG TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1159 PM CDT THU MAR 29 2012 .DISCUSSION...SEE AVIATION SECTION FOR 06Z TAFS. && .AVIATION...CONVECTIVE DEBRIS CLOUDINESS WILL REMAIN OVER THE REGION FROM LARGE CONVECTIVE COMPLEX OVER DEEP SOUTH TEXAS. THERE WILL BE SOME RESIDUAL PRECIP AROUND LAREDO AND POSSIBLY INTO THE ALICE AREA FOR A COUPLE MORE HOURS. EXPECT MVFR CEILINGS WILL BE PREVALENT OVER THE COASTAL PLAINS WITH IFR CIGS OVER THE VCT AREA THROUGH EARLY MORNING. EXPECT IMPROVEMENT IN CEILINGS BY LATE MORNING AND VFR BY 18Z. MODELS ARE NOT SHOWING MUCH IN THE WAY OF CONVECTIVE ACTIVITY FOR FRIDAY BUT THINK THERE WILL BE SOME DEVELOPMENT ON THE SEA BREEZE BOUNDARY IN THE AFTERNOON. AIR MASS IS EXPECTED TO BE VERY UNSTABLE AGAIN AS IT WAS ON THURSDAY. MVFR CEILINGS ARE EXPECTED TO MOVE BACK INTO THE COASTAL PLAINS BY 03Z SATURDAY. && .PREV DISCUSSION... /ISSUED 910 PM CDT THU MAR 29 2012/ DISCUSSION...AS THE MESOSCALE CONVECTIVE VORTEX LIFTED INTO SOUTHEAST TEXAS LATE THIS AFTERNOON...AIR MASS BECAME STRONGLY UNSTABLE OVER THE COASTAL PLAINS WITH LIFTED INDECES AROUND -10 DEGREES AND CAPE VALUES AROUND 3000 J/KG. STRONG TO SEVERE STORMS DEVELOPED ALONG THE SEA BREEZE WITH THE MOST SEVERE AFFECTING ROBSTOWN WITH DAMAGING WINDS AND HAIL UP TO 2 INCHES. MOST OF THE ACTIVITY DIMINISHED WITH THE LOSS OF HEATING AND WEAK STABILIZATION BEHIND THE SEA BREEZE. BUT MORE ACTIVITY LINGERING OVER DEEP SOUTH TEXAS HAS SHOWN A DRIFT TO THE NORTHEAST AHEAD OF AN UPPER LEVEL SHORT WAVE TROUGH NORTH OF MONTERREY MOVES EAST-NORTHEAST. WILL MODIFY POPS TO SHOW BEST CHANCES FROM SOUTHWEST TO LIMITED NORTHEAST AND OVER THE GULF WATERS. MODELS SHOW THIS VERY UNSTABLE AIRMASS TO REMAIN OVER THE REGION FOR FRIDAY. FORECAST INSTABILITY FIELDS SHOW CAPE FROM 3500-4000 J/KG OVER THE INLAND COASTAL PLAINS AND BRUSH COUNTRY WITH LIFTED INDEX VALUES AROUND -11 TO -12 DEGREES WITH LIMITED CONVECTIVE INHIBITION. RAISED POPS TO LOW END CHANCE OVER MOST OF THE BRUSH COUNTRY TO INLAND COASTAL PLAINS FRIDAY AFTERNOON. POTENTIAL FOR ISOLATED SEVERE THUNDERSTORMS AGAIN TOMORROW AFTERNOON INTO THE EVENING. PREV DISCUSSION... /ISSUED 642 PM CDT THU MAR 29 2012/ DISCUSSION...SEE AVIATION SECTION BELOW. AVIATION...ONGOING CONVECTION ALONG A SEA BREEZE THIS AFTERNOON WILL CONTINUE TO MOVE SLOWLY WEST THRU THE EVENING HOURS. AREAS AHEAD OF AND IN THE WAKE OF THE SEA BREEZE ARE GENERALLY VFR. THESE STORMS ARE EXPECTED TO DIMINISH OVER THE NEXT TWO TO THREE HOURS...HOWEVER THUNDERSTORMS ACROSS MEX ARE EXPECTED TO AFFECT LRD LATER THIS EVENING TOWARD MIDNIGHT. THIS SYSTEM IS EXPECTED TO GENERALLY MOVE E TO SE OVERNIGHT ACROSS S TX. GENERALLY MVFR CIGS ARE EXPECTED TO DVLP OVERNIGHT WITH IFR/LIFR CONDITIONS IN AND NEAR TSRA`S. ONCE THIS STORM SYSTEM HAS EXITED THE AREA...VFR CONDITIONS ARE EXPECTED TO DVLP BY FRI AFTERNOON. PREV DISCUSSION... /ISSUED 333 PM CDT THU MAR 29 2012/ SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...ATMOSPHERE WAS PRETTY WORKED OVER TODAY FROM LAST NIGHT/S CONVECTION WITH REMNANT MCV NOTED ACROSS HGX CWA. LOW CLOUD DECK HAS BEEN SLOW TO MIX OUT ACROSS BRUSH COUNTRY...BUT IS FINALLY STARTING TO DO SO AND ALL IN ALL ATMOSPHERE IS GRADUALLY BECOMING MORE UNSTABLE AGAIN. PATTERN LOOKS MORE LIKE MAY THAN MARCH WITH VORT MAXES TRAVERSING ACROSS SOUTH TX IN THE MID LEVEL FLOW PRODUCING CONTINUING CHANCES OF SHOWERS AND THUNDERSTORMS. OVER THE PAST HOUR CONVECTION HAS BEEN TRYING TO FIRE ALONG THE SEABREEZE AS IT MOVES INLAND. THE COMBINATION OF AN INCREASINGLY UNSTABLE AIRMASS AND AN AXIS OF HIGHER PWATS DRAPED FROM SW TO NE ACROSS THE COASTAL PLAINS SHOULD ALLOW ADDITIONAL CONVECTION TO DEVELOP ALONG THE SEABREEZE THROUGH EARLY EVENING. ATTENTION THEN TURNS TO THE WEST WHERE CONVECTION IS CURRENTLY DEVELOPING ACROSS HIGHER TERRAIN OF OLD MEX. HIRES MODELS PROVIDE A VARIETY OF OUTPUT WITH 4KM WRF DEVELOPING SIGNIFICANT CONVECTION ACROSS MUCH OF S TX THIS EVENING WHILE HRRR IS MORE OF THE ISOLATED VARIETY. HRRR INITIALIZED MUCH BETTER THAN 4KM WRF SO HAVE LEANED MORE TOWARDS ITS OUTPUT FOR TONIGHT. TRIMMED POPS SOME FOR TONIGHT OUT WEST BUT NOT AS DRY AS HRRR GIVEN UNCERTAINTY. ANY STORMS THAT DEVELOP MAY BRIEFLY PULSE TO STRONG/SEVERE LEVELS BUT WIDESPREAD SEVERE WX IS NOT CURRENTLY ANTICIPATED. TOMORROW S TX IS PROG TO BE IN BETWEEN VORT MAXES AND SHOULD GENERALLY BE DRY ASIDE FROM ISOLATED CONVECTION DEVELOPING FROM DAYTIME MIXING AND INTERACTIONS WITH THE SEABREEZE. STRONGER VORT MAX PROG TO APPROACH AREA FRI NIGHT WITH GOOD PVA...INSTABILITY...AND MOISTURE TO EXIST FOR MCS FEATURE TO POSSIBLY DEVELOP ALONG RIO GRANDE AND MOVE WEST THROUGH THE NIGHT. STRONG WINDS AND HAIL MAY OCCUR IF MCS DEVELOPS BUT FINER DETAILS TO COME IN FUTURE FORECASTS. TEMPS THROUGH THE SHORT TERM PERIOD WILL BE DEPENDENT ON IF THEY BECOME RAIN COOLED AND HOW MUCH CLOUD COVER DEVELOPS FROM CONVECTION. FOR NOW HAVE GONE GENERALLY WITH A MOS BLEND. LONG TERM (SATURDAY THROUGH THURSDAY)...EXPECT NOCTURNAL MCS TO BE MOVING OUT OF THE FORECAST AREA BY THE START OF THE EXTENDED PERIOD. HAVE ADDED 20 POPS TO THE FAR EAST TO ACCOUNT FOR TIMING OF THE CONVECTION POSSIBLY LASTING INTO THE SATURDAY MORNING TIME PERIOD. EXPECT TIMING WILL BE SIMILAR TO THE CONVECTION THE PAST TWO NIGHTS. BY SATURDAY NIGHT LOOKS LIKE ALTHOUGH THUNDERSTORMS OVER THE SIERRA MADRE ARE POSSIBLE...THE MOVEMENT SHOULD BE QUITE DIFFERENT THAN OTHER NIGHTS HAVE BEEN AND WILL BE. CORFIDI VECTORS AND THICKNESS CONTOURS WOULD INDICATE AN ALMOST DUE SOUTH MOVEMENT SO HAVE OPTED TO TAKE PRECIP WORDING OUT OF THE FORECAST FOR SATURDAY NIGHT. COLD FRONT STILL ON TRACK FOR MONDAY...WITH RATHER IMPRESSIVE MODEL AGREEMENT FOR FOUR DAYS OUT. TIMING IS CLOSER TO THE SLOWER ECMWF FROM YDAY RUNS AND HAVE STUCK MAINLY WITH THE ECMWF FOR THE FORECAST THIS AFTERNOON. PRECIP CHANCES DO NOT LOOK GREAT AT THIS TIME...WITH SLIGHT CHANCES IN THE EAST. BEHIND THE FRONT LOOK FOR A MODEST COOL DOWN OF 5 TO 10 DEGREES FOR THE NEXT FEW DAYS WITH DRIER CONDITIONS AND MOSTLY CLEAR SKIES. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 69 86 68 86 68 / 40 30 30 20 10 VICTORIA 67 84 67 84 68 / 20 20 20 20 10 LAREDO 68 92 69 93 69 / 50 20 50 10 10 ALICE 68 89 66 89 68 / 50 30 40 10 10 ROCKPORT 69 82 69 80 70 / 20 20 20 20 10 COTULLA 67 86 65 88 67 / 40 30 50 10 10 KINGSVILLE 69 87 68 88 67 / 50 30 30 20 10 NAVY CORPUS 71 81 68 82 69 / 30 20 20 20 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ TMT/89...SHORT TERM/AVIATION
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
949 PM EDT SAT MAR 31 2012 .SYNOPSIS... WEAK HIGH PRESSURE WILL CONTINUE TO BUILD INTO OUR AREA TONIGHT. THIS HIGH WILL MOVE SOUTHEAST OF OUR AREA ON SUNDAY. ANOTHER APPROACHING COLD FRONT WILL ENTER OUR AREA BY MONDAY MORNING. && .NEAR TERM /THROUGH SUNDAY/... AS OF 945 PM EDT SATURDAY... PERSISTENT CLUSTER OF SCATTERED THUNDERSTORMS FROM GRAYSON COUNTY INTO WILKES COUNTY WAS GRADUALLY DRIFTING EAST. AREAS RADAR CONTINUES TO SHOW ISOLATED SHOWERS AND THUNDERSTORMS ON THE EASTERN AND SOUTHEAST FRINGE OF THE COUNTY WARNING AREA. LOCAL WRF AND HRRR GUIDANCE HAD PRECIPITATION ENDING ACROSS THE FORECAST AREA BY MIDNIGHT. ADJUSTED PROBABILITY OF PRECIPITATION IN THE FORECAST FOR THIS TIMING. ALSO ADDED PATCHY FOG IN FOG THE GREENBRIER RIVER VALLEY AND IN THE AREAS ACROSS THE SOUTHWEST COUNTY WARNING AREA THAT HAD RAIN SATURDAY AFTERNOON AND EVENING. DEW POINTS HAVE ALREADY DROPPED INTO THE UPPER 30S TO LOWER 40S IN THE FAR NORTHERN COUNTY WARNING AREA. SURFACE DEW POINTS WILL CONTINUE TO LOWER BEHIND THE FRONT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA. HAD MADE SLIGHT ADJUSTMENTS TO OVERNIGHT LOWS BASED ON 9PM OBS...CLOUD COVER AND THE LATEST LAMP GUIDANCE. NAM AND LOCAL WRF HAD LAYER OF LOW CLOUDS SPREADING ACROSS CENTRAL AND EASTERN VIRGINIA OVERNIGHT...AND REACHING AS FAR WEST AS LYNCHBURG AND DANVILLE. HAVE ADDED MORE CLOUD COVER IN THE EAST SINCE CEILINGS ARE ALREADY LOWERING JUST NORTH AND EAST OF THE FORECAST AREA. THE CLOUDS IN THE EAST MAY TAKE MOST OF THE MORNING TO MIX OUT. BUFKIT SOUNDINGS WERE SUGGESTING THAT CLOUDS MAY NOT BECOME SCATTERED UNTIL AFTER 11AM. AS OF 330 PM EDT SATURDAY... SURFACE ANALYSIS INDICATES THAT THE COLD FRONT IS LOCATED ACROSS OUR SOUTHERNMOST TIER OF COUNTIES THIS AFTERNOON...AND IS CONTINUING TO MOVE SOUTHEAST. RADAR HAS INDICATED THAT SPOTTY SHOWER ACTIVITY...AND A FEW THUNDERSTORMS...HAS DEVELOPED ACROSS OUR AREA WITH AFTERNOON HEATING...BUT NONE OF THIS ACTIVITY IS VERY STRONG. THAT STATED...CANNOT RULE OUT ONE OR TWO STRONG BUT SHORT LIVED THUNDERSTORMS DEVELOPING DURING EARLY EVENING. WEAK HIGH PRESSURE WILL CONTINUE TO BUILD INTO OUR AREA THIS EVENING...WHICH WILL RESULT IN NORTHWESTERLY FLOW THROUGH THE FIRST FEW HOURS OF SUNDAY MORNING. THIS DOWNSLOPE FLOW WILL ALLOW CLOUD COVER TO DIMINISH ACROSS MUCH OF OUR AREA...ESPECIALLY AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. HOWEVER...WEATHER FORECAST MODELS HAVE INDICATED THE POSSIBILITY OF LOW CLOUDS REDEVELOPING TONIGHT ALONG THE EAST FACING SLOPES IN SOUTHEAST WEST VIRGINIA AND THE MOUNTAIN EMPIRE...AS RESIDUAL LOW LEVEL MOISTURE BECOMES WEDGED ALONG THE RIDGELINES. WITH LIGHT WINDS ACROSS THE AREA...WILL ALSO BE LOOKING AT THE POSSIBILITY OF PATCHY FOG DEVELOPING ACROSS PORTIONS OF THE MOUNTAINS...ESPECIALLY IN THE RIVER VALLEYS. THE HIGH WILL SLIDE SOUTHEAST BY SUNRISE SUNDAY MORNING...AND WE WILL BEGIN TO SEE SOUTHERLY WINDS TAKE OVER. WITH PLENTY OF DRY AIR ALOFT...EXPECT THAT ANY FOG AND LOW CEILINGS WILL BURN OFF BY 10 AM...AND EXPECT MOSTLY CLEAR SKIES THROUGH EARLY AFTERNOON AREAWIDE. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS OF 330 PM EDT SATURDAY... ON SUNDAY NIGHT...THE NORTHEAST U.S. UPPER TROF DEEPENS IN RESPONSE TO A SHORTWAVE MOVING SOUTHEAST. THIS WILL DRIVE A COLD FRONT THROUGH THE FORECAST AREA AND SPARK A COMPLEX OF STORMS AS LOW LEVEL THETA-E RIDGE INCREASES IN ADVANCE OF THE FRONT. BEST LOW LEVEL CONVERGENCE WILL BE FOUND SE WV AND WEST OF I-77 WHERE HIGHEST POPS WERE PLACED. INCREASED LOW TEMPERATURES A COUPLE OF DEGREES WITH A FAIR AMOUNT OF CLOUDS AND MIXING. AS WEAK HIGH PRESSURE TRIES TO WEDGE DOWN THE EASTERN U.S. A WEAK LOW LEVEL CONVERGENCE ZONE IS ESTABLISHED IN THE FAR SOUTHWEST PORTION OF THE FORECAST AREA. WITH THE GREATEST INSTABILITY EXPECTED TO BE LOCATED HERE...WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE. LEANED TOWARD THE COOLER NAM MOS GUIDANCE FOR HIGHS IN THE EAST WITH A LOW LEVEL NORTHEAST FLOW IN PLACE. FOR MONDAY NIGHT AND TUESDAY...AN UPPER LEVEL RIDGE TRIES TO BUILD OVER THE REGION...BUT IS QUICKLY FLATTENED BY A NORTHERN STREAM SYSTEM MOVES ACROSS SOUTHERN CANADA AND THE NORTHERN GREAT LAKES. THE LOW LEVEL FLOW IN ADVANCE OF THIS SYSTEM COMES AROUND TO THE SOUTH/SOUTHWEST USHERING IN HIGHER DEWPOINTS AND POTENTIALLY A DECK OF LOW LEVEL STRATUS CLOUDS WITH GOOD MOISTURE ADVECTION. ISENTROPIC LIFT ON THE LEADING EDGE OF THIS MAY BRING ANOTHER ROUND OF RAIN THE FAR SOUTHWEST MONDAY NIGHT...WITH SHOWERS AND THUNDERSTORMS DEVELOPING IN ADVANCE OF THE FRONT IN THE NORTHERN AND WESTERN PORTION OF THE FORECAST AREA ON TUESDAY UNDER THE INSTABILITY AXIS. TEMPERATURE FORECAST TUESDAY IS A TRICKY ONE AND HIGHS WILL DEPEND ON THE AMOUNT OF CLOUD COVER SEEN. WITH THE POTENTIAL FOR LOW CLOUDS TO ADVANCE INTO OUR AREA...DROPPED HIGHS A FEW DEGREES TOWARD THE COOLER LOCALLY DERIVED MOS FORECAST HIGHS. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 330 PM EDT SATURDAY... FOR THE LONG TERM PORTION OF THE FORECAST...WE LEANED HEAVILY ON THE 00Z ECMWF SOLUTION WHICH SHOWS BETTER RUN TO RUN CONSISTENCY COMPARED TO THE GFS WITH ITS HANDLING OF THE TIMING AND EVOLUTION OF A CUT OFF LOW DRIFTING ACROSS THE SOUTHERN PLAINS...THEN THE SOUTHEAST U.S. LATE IN THE PERIOD. THE ECMWF IS ALSO IN BETTER AGREEMENT WITH THE CANADIAN AND UKMET SOLUTIONS. THE GFS ENSEMBLE MEMBERS SHOW A WIDE RANGE OF POTENTIAL SOLUTIONS TO THE STRENGTH AND LOCATION OF THIS UPPER LEVEL LOW WHICH GIVES US LOW CONFIDENCE IN THE OPERATIONAL GFS SOLUTION. SOME SIGNIFICANT MODIFICATIONS WERE MADE TO THE FORECAST BASED ON THE ECMWF FORECAST. FIRST...WITH THE SLOWER TIMING...NOW EXPECT THE COLD FRONT TO MOVE THROUGH LATE WEDNESDAY...ALLOWING TEMPERATURES TO BE WELL ABOVE NORMAL WITH A DEEP WEST...DOWNSLOPING FLOW...WITH THUNDERSTORMS POSSIBLE ALONG THE FRONT. BEHIND THIS FRONT...TRENDED TEMPERATURES DOWN BY SEVERAL DEGREES THUR-SATURDAY AS A LOW LEVEL NORTHEAST...THEN EAST...FLOW DEVELOPS WITH THE UPPER LOW TO OUR SOUTH AND CANADIAN HIGH PRESSURE BUILDING IN THE NE U.S. WITH THE NAO FORECAST TO BECOME NEGATIVE AND THE GLOBAL WIND OSCILLATION (GWO) IN A FAVORABLE PHASE FOR COOLER THAN NORMAL CONDITIONS IN THE EASTERN U.S...THE COOLER ECMWF TEMPERATURES APPEAR REASONABLE. DEPENDING ON THE LOCATION OF THE UPPER LOW...SHOWERS/RAIN WILL BE POSSIBLE EACH DAY...ESPECIALLY FOR THOSE FAVORED EASTERN UPSLOPE AREAS AND TO THE SOUTH...CLOSER TO THE LOCATION OF THE UPPER LOW. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... AS OF 130 PM EDT SATURDAY... ISOLATED THUNDERSTORMS WILL CONTINUE IN FAR SOUTHWEST VIRGINIA AND EXTREME NORTHWEST NORTH CAROLINA AND IN SOUTH CENTRAL VIRGINIA THROUGH MIDNIGHT. THESE STORMS ARE NOT EXPECTED TO IMPACT BCB/LWB/BLF/LYH/ROA OR DAN. MODELS WERE SHOWING LOW LEVEL MOISTURE BANKING UP AGAINST THE WESTERN SLOPES OF THE APPALACHIANS TONIGHT. HAVE KEPT MVFR CEILINGS IN THE TAF AT BLF FOR LATE TONIGHT THROUGH SUNRISE. EXPECT A SMALL ENOUGH TEMPERATURE/DEW POINT SPREAD AT LWB FOR FOG TO FORM OVERNIGHT. HAVE TYPICAL LIFR CONDITIONS AT LWB THROUGH SUNRISE. MOISTURE IN THE WEST IS SHALLOW. FOG AND CLOUDS WILL DISSIPATE QUICKLY IN THE MORNING. NAM AND LOCAL WRF WERE SHOWING STRONGER NORTHEAST SURFACE AND LOW LEVEL WINDS TONIGHT THAN THE OTHER GUIDANCE AND BRINGING MVFR CLOUDS INTO LYH AND DAN AFTER 06Z. ALREADY SEEING THE LOW CLOUDS ADVANCING WEST ON SATELLITE LOOPS. MEDIUM CONFIDENCE THAT THIS CLOUD LAYER WILL REACH LYH/DAN AND HIGHER CONFIDENCE THAT THE CLOUDS WILL STAY EAST OF ROA. MAKE TAKE MOST OF THE MORNING TO MIX OUT TO VFR. BUFKIT WAS NOT SHOWING IMPROVEMENT UNTIL AFTER 15Z/11AM. THE NEXT THREAT FOR WIDESPREAD FLIGHT RESTRICTIONS WILL OCCUR LATE SUNDAY NIGHT OR ON MONDAY...POSSIBLY CONTINUING INTO THE MID WEEK. WEAK SHORT WAVES AND MOISTURE STREAMING NORTHEAST OVER A STALLED FRONT OVER/NEAR THE AREA...MAY SET THE STAGE FOR MVFR...AND POTENTIALLY LOWER...FLIGHT RESTRICTIONS...ESPECIALLY OVER/IN THE MOUNTAINS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/NF NEAR TERM...AMS/NF SHORT TERM...PH LONG TERM...PH AVIATION...AMS/NF
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
854 PM CDT SAT MAR 31 2012 .UPDATE... SPC ADDED A SLGT RISK ON DAY 1 UPDATE THAT EXTENDS FROM EAST CENTRAL IOWA INTO EAST CENTRAL ILLINOIS NORTH OF A DECENT LOW LEVEL BAROCLINIC ZONE. THIS RISK AREA BARELY CLIPS SOUTHERN LAFAYETTE COUNTY. LATEST RUC GUIDANCE IN GOOD AGREEMENT WITH 18Z NAM/GFS IN TAKING STRONGEST 700 MB WARM ADVECTION SOUTH OF WISCONSIN. INITIAL THUNDERSTORMS EAST OF DSM HAVE DEVELOPED RIGHT IN THE MIDDLE OF THIS 700 MB ADVECTION ZONE...AND SHOULD RIDE DOWN THE BAROCLINIC ZONE THROUGH THE HEART OF SLIGT RISK. DECENT 850 MB POSITIVE THETA-E ADVECTION IS SHOWN ON THE MODELS BRUSHING SOUTHERN WISCONSIN...ALONG WITH LIGHT QPF. SO THIS CONTINUES TO JUSTIFY LOW POPS ACROSS THE SOUTH. PERSISTENT AND PESKY LOW CLOUD DECK AS FINALLY LIFTED ACROSS SOUTHERN HALF...BUT IS TOPPED BY MID/HIGH CLOUDS. THESE SHOULD CLEAR LATE TONIGHT AS WEAK DISTURBANCE SLIDES BY WHICH OPENS THE DOOR FOR FOG/STRATUS TO REDEVELOP TOWARD MORNING. 18Z NAM KEPT HIGH 925 MB RH THROUGH 21Z FOR SOUTHERN WISCONSIN...WHICH IS CAUSE FOR CONCERN ON HIGH TEMPERATURE FORECAST AND SKY COVER ONCE AGAIN. DID NOT ADJUST THESE YET BUT CAUTION IS ADVISED. && .AVIATION/06Z TAFS/... STRATUS LIFTING NORTH OF THE TAF SITES FOR THE TIME BEING. THUNDERSTORMS SHOULD STAY SOUTH OF THE TAF SITES SO DID NOT INCLUDE THEM AS PROBABLY A BIT TOO LOW. CLEARING OF MIDDLE/HIGH CLOUDS LATER TONIGHT OPENS THE DOOR FOR FOG AND STRATUS FORMATION BETWEEN 09Z AND 14Z. WENT WITH LIFR VISIBILITY AND IFR CEILINGS BUT DID NOT GO 1/4SM PER BOTH GFS AND NAM MOS OUTPUT. THIS IS CERTAINLY POSSIBLE AND WILL TAKE A CLOSE LOOK PRIOR TO NEXT PRIMARY TAF ISSUANCE AT 00Z GUIDANCE TO SEE IF WE NEED TO GO VLIFR. THIS STRATUS DECK COULD LINGER WELL INTO THE DAY BUT LIKELY AS MVFR BUT CURRENTLY CLEAR THINGS OUT BY 18Z. THIS TOO WILL BE PROBLEMATIC AND MAY NEED REVISION. && .PREV DISCUSSION... /ISSUED 310 PM CDT SAT MAR 31 2012/ VERY SHORT TERM...TONIGHT AND SUNDAY. LOW CLOUD DECK CONTINUES TO HOLD STRONG ACROSS THE REGION EARLY THIS AFTERNOON...THOUGH STARTING TO SEE SOME OF THIS DECK MIX OUT IN NORTHEAST ILLINOIS. ALSO SEEING CEILING HEIGHTS RISE AS WELL. AREA RUC FORECAST SOUNDINGS AND TAMDAR SOUNDINGS SHOWING THIS DECK TO BE ABOUT 1000 TO 2000 FEET THICK. RUC/NAM SOUNDINGS AND HIGH RESOLUTION RAPID REFRESH MODEL SHOW THIS LOW DECK SLOWLY MIXING OUT THROUGH LATE THIS AFTERNOON/EARLY EVENING. HOWEVER...MID TO HIGH CLOUDS ASSOCIATED WITH WARM AIR ADVECTION WILL CONTINUE TO STREAM SOUTHEAST THROUGH THE REGION DURING THIS TIME. THUS...HAVE GONE WITH MOSTLY CLOUDY WORDING IN MOST AREAS INTO THE EARLY EVENING. DID MIX OUT LOW CLOUDS IN THE FAR SOUTHEAST COUNTIES BY 00Z SUNDAY...ASSUMING CURRENT TREND CONTINUES. THIS MAY HAVE TO BE ADJUSTED RIGHT BEFORE FORECAST ISSUANCE. ONCE LOW CLOUDS MIX OUT...MIDDLE TO HIGH CLOUDS SHOULD DEVELOP SOME BREAKS LATER THIS EVENING AND OVERNIGHT. WARM AIR ADVECTION CONTINUES TONIGHT...AND EXPECT A NON DIURNAL TREND WITH SLOWLY RISING TEMPERATURES...GIVEN THE COOL TEMPERATURES TODAY. RISING DEW POINTS AND LIGHT AND VARIABLE WINDS BY LATE TONIGHT/EARLY SUNDAY SHOULD ALLOW FOR FOG FORMATION ACROSS THE AREA. PATCHY DENSE FOG IS POSSIBLE IN LOW LYING AREAS...AND WILL HAVE TO BE WATCHED FOR MORE WIDESPREAD DEVELOPMENT IF MIDDLE TO HIGH CLOUDS MOVE OUT QUICKER THAN EXPECTED. 12Z NAM/GFS/CANADIAN/ECMWF MODELS SHOWING WARM FRONT AND BULK OF POSSIBLE ELEVATED CONVECTION LATER TONIGHT INTO SUNDAY MORNING STAYING JUST SOUTH OF THE AREA. STILL HAVE 25 TO 30 KNOT WEST SOUTHWESTERLY LOW LEVEL JET POINTING TOWARD THE AREA BY 06Z SUNDAY...THEN VEERS DUE WEST LATER TONIGHT. NOT A LOT OF MOISTURE ADVECTION AT 850MB INTO THE REGION WITH THIS FEATURE...BUT AREA FORECAST SOUNDINGS DO SHOW 500 TO 1000 J/KG ELEVATED CAPE WITH DECENT EFFECTIVE LAYER SHEAR. LOW WET BULB ZERO HEIGHTS SUGGEST SMALL HAIL IS POSSIBLE WITH ANY STORMS THAT DO FORM AND MAKE IT INTO THE AREA. WENT WITH CHANCE POPS IN THE FAR SOUTHERN COUNTIES BETWEEN 06Z AND 12Z SUNDAY...WITH SLIGHT CHANCE POPS TO THE NORTH. KEPT SLIGHT CHANCE WORDING SOUTHWEST OF MADISON MID TO LATE EVENING...AND IN THE FAR SOUTHEAST SUNDAY MORNING. DRY AND PARTLY SUNNY SUNDAY AFTERNOON WITH LACK OF UPWARD VERTICAL MOTION AND MOISTURE IN THE AREA. ONSHORE WINDS WILL KEEP LAKESHORE AREAS MUCH COOLER...IN THE 50S...THAN WELL INLAND...IN THE 70S. SHORT TERM...SUNDAY NIGHT THROUGH TUESDAY. SHORT TERM GUIDANCE COMING INTO REASONABLE AGREEMENT CONCERNING SURFACE FEATURES SUNDAY NIGHT AND MONDAY. INCREASED SUBSIDENCE ASSOCIATED WITH EXPANDING MID-LEVEL RIDGING OCCURRING ON SUNDAY...PERSISTS INTO MONDAY. SHARP RIDGE DIVERTS STRONGER SHORT WAVES CAUGHT IN SOUTHWESTERLY FLOW TO THE NORTH AND WEST OF CWA. IN ADDITION...850H LOW LEVEL JET REMAINS WEST AND WELL SOUTH OF AREA...AT LEAST INITIALLY. WEAKER LLJ DEVELOPS OVER WI ON MONDAY WHICH USHERS IN HIGHER LOW LEVEL RH. WARM MID-LEVELS RESULT IN CAPPING FOR MOST OF MONDAY...BUT PASSING WEAK WAVE ACROSS CENTRAL WI MAY HAVE JUST ENOUGH FORCING TO BREAK THROUGH CAP. HENCE WL CONTINUE SCHC POPS FOR MON OVER MOST OF CWA...EXCEPT FAR SOUTH. EXPCD BKN-OVC CLOUD COVER ACCOMPANYING SURGE OF HIGHER RH WL ALSO PREVENT STRONGLY UNSTABLE AIRMASS. BETTER CHANCE FOR PRECIP AND T MONDAY NIGHT AS MAIN SHORT WAVE TROUGH MOVES SOUTHEAST ACROSS WI. AT THIS TIME...RIGHT EXIT OF 300H JET AND LAYER FN VECTOR RESPONSE TO FRONTOGENESIS PASS THROUGH SRN WI...SO WL CONTINUE HIGH CHANCE POPS FOR NOW. LACK OF MID LEVEL WAVE AND INDICATIONS OF POSSIBLE SPLIT FORCING PREVENT ME FROM GOING WITH LIKELY WORDING FOR NOW. MID-LEVEL TROUGH EXITS SRN WI TUE MRNG WITH DRIER...NLY FLOW SETTLING INTO THE REGION. WITH WARM FRONT REMAINING TO THE SOUTH OF WI FOR MONDAY...NEEDED TO LWR MAX TEMPS SLIGHTLY...ESPECIALLY IN THE EAST DUE TO SELY WINDS AND EXPCD CLOUDS. LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. THIS PERIOD STILL LOOKING GENERALLY DRY AND QUIET WITH TEMPERATURES AVERAGING ABOVE THE SEASONAL NORMAL FOR EARLY APRIL. THERE MAY BE A NIGHT OR TWO WHEN FROST WILL BE A POSSIBILITY WITH TEMPERATURES FALLING INTO THE MID TO UPPER 30S LATE AT NIGHT...ESPECIALLY THURSDAY NIGHT. LINGERING WEAK MID-LEVEL TROUGH OVER SRN WI ON TUESDAY WILL SUCCUMB TO INFLUENCE OF INCREASING LARGE SCALE RIDGING BUILDING INTO THE WRN GTLAKES AND FURTHER WEAKEN AND MOVE EAST OF AREA BY TUESDAY NIGHT. HENCE DRY CONDITIONS STILL ANTICIPATED FOR THE PERIOD FROM TUESDAY NIGHT THROUGH FRIDAY. HOWEVER ONE FLY POSSIBLY LANDING IN OUR SOUP IS THE TREND BY LAST SEVERAL DETERMINISTIC RUNS OF BOTH THE GFS AND ECWMF PUSHING CUTOFF LOW OVER SRN PLAINS FARTHER NORTH INTO THE CENTRAL PLAINS BY MID-WEEK. ACTUALLY WITH LONG WAVE TROF SPREADING FROM THE NORTHERN PACIFIC INTO THE NW CONUS...SEEMS REASONABLE THAT CUTOFF LOW WOULD TRACK FARTHER NWD. OTHER LONG RANGE GUIDANCE INCLUDING GEM-NHEM AND UKMO TRACK CUTOFF LOW EAST ACROSS CENTRAL MS VALLEY REGION WED NGT AND THU WHILE LINGERING HIGH PRESSURE OVER THE WRN GTLAKES SUPPRESSES LOW TO THE SOUTH. 12Z ECMWF DETERMINISTIC RUN...ECMWF ENSEMBLE MEAN AND HPC ALSO LEANING TWD THIS CONTINUED DRY SOLUTION. LONG WAVE TROUGH OVER WRN CONUS BY THE END OF THE WEEK WILL EVENTUALLY RESULT IN INCREASING WARM AIR ADVECTION AND MOISTURE RETURNING TO WISCONSIN LATER IN THE WEEKEND. HENCE THREAT FOR PRECIP MAY INCREASE SAT NGT INTO SUN. AVIATION /00Z TAFS/...MAINLY MVFR CEILINGS ARE EXPECTED TO LINGER THROUGH LATE THIS AFTERNOON ACROSS TAF SITES...BEFORE MIXING OUT BY EARLY EVENING. VFR CEILINGS WITH MID TO HIGH CLOUDS THEN EXPECTED FROM MID TO LATE EVENING...BEFORE SOME BREAKS OCCUR LATER TONIGHT AND INTO SUNDAY. BEST CHANCES FOR ANY SHOWERS OR STORMS WOULD BE BETWEEN 06Z AND 12Z SUNDAY...BUT BEST CHANCES REMAIN JUST SOUTH OF THE FORECAST AREA...SO WILL NOT MENTION IN TAFS AT THIS TIME. LIGHT WINDS BETWEEN 06Z AND 15Z SUNDAY...WITH LINGERING LOW LEVEL MOISTURE...SHOULD ALLOW FOR IFR/LIFR FOG FORMATION. SOME HIGH CLOUDS LINGERING SHOULD PREVENT WIDESPREAD DENSE FOG...BUT WILL HAVE TO BE WATCHED CLOSELY IN CASE THEY CLEAR OUT QUICKER THAN EXPECTED. VFR CONDITIONS THEN EXPECTED THROUGH THE REST OF SUNDAY. WINDS SHOULD BECOME EAST NORTHEAST ON SUNDAY...AS WARM FRONT STAYS SOUTH OF THE AREA. MARINE... WINDS AND WAVES WILL APPROACH SMALL CRAFT ADVISORY LEVELS MONDAY THROUGH TUESDAY ACROSS THE NEARSHORE WATERS...AS LOW PRESSURE MOVES SOUTH OF THE AREA. ONSHORE WINDS MONDAY SHOULD BUILD HIGH WAVES...WITH TIGHT PRESSURE GRADIENT BRINGING BRISK ONSHORE WINDS AND HIGH WAVES MONDAY NIGHT AND TUESDAY. HIGH WAVES MAY LINGER INTO TUESDAY NIGHT BEFORE DIMINISHING. CONFIDENCE... TONIGHT AND SUNDAY...MEDIUM. SUNDAY NIGHT THROUGH TUESDAY...MEDIUM. TUESDAY NIGHT THROUGH SATURDAY...MEDIUM TO HIGH. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...CRAVEN TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD SUNDAY NIGHT THROUGH SATURDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
659 PM CDT SAT MAR 31 2012 .SHORT TERM...THROUGH MONDAY NIGHT 301 PM CDT SAT MAR 31 2012 MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES TONIGHT AND THEN SUNDAY NIGHT THROUGH MONDAY NIGHT. SURFACE ANALYSIS THIS AFTERNOON SHOWS HIGH PRESSURE CENTERED OVER LOWER MICHIGAN. A WEAK AREA OF LOW PRESSURE WAS OVER SOUTHEAST SOUTH DAKOTA WITH A WARM FRONT ALONG THE MISSOURI RIVER INTO NORTHERN MISSOURI. VISIBLE SATELLITE SHOWS THE CLOUDS HAVE HUNG ON TOUGH OVER THE ENTIRE AREA SO FAR TODAY. THE 31.12Z NAM SUGGESTS THE LOW LEVEL MOISTURE WITH THESE CLOUDS WILL REMAIN OVER THE REGION THROUGH THE NIGHT WHILE THE BUFKIT SOUNDINGS WOULD SUGGEST THE LOW CLOUDS SHOULD BREAK UP YET THIS AFTERNOON OR EVENING. SATELLITE TRENDS CERTAINLY DO NOT SUPPORT THE CLEARING OCCURRING AS FAST AS THE SOUNDINGS WOULD SUGGEST SO HAVE GONE MORE PESSIMISTIC ON THE CLOUD COVER HOLDING ON TO FOR MOST OF THE NIGHT. THE OTHER CONCERN FOR TONIGHT IS WHETHER ANY STORMS ARE GOING TO DEVELOP OVER THE AREA AS THE WARM FRONT LIFTS NORTH. CURRENT MODEL CONSENSUS SUGGESTS THE WARM FRONT WILL MOVE FROM ITS CURRENT POSITION INTO CENTRAL IOWA AND NORTHERN ILLINOIS OVERNIGHT. AS IT DOES...THE LOW LEVEL JET WILL FORM WITH THE NOSE OF THE MOISTURE TRANSPORT IMPINGING ON THE FRONT OVER EASTERN IOWA. SOME WEAK TO MODERATE FRONTOGENESIS SHOULD OCCUR WITH THE FRONT IN THE 1000-700 MB LAYER AS FAR NORTH AS NORTHEAST IOWA AND SOUTHWEST WISCONSIN. THIS AREA SHOULD ALSO SEE BETWEEN 1 AND 3 UBAR/S OF UP GLIDE ON THE 305K ISENTROPIC SURFACE. THIS FORCING COMBINED WITH THE MOISTURE TRANSPORT SHOULD ALLOW SOME SHOWERS AND THUNDERSTORMS TO FORM ALONG AND NORTH OF THE FRONT. THE POSITION OF THE FRONT LOOKS TO BE FARTHER SOUTH THAN PREVIOUS RUNS HAVE SUGGESTED SO HAVE MOVED THE RAIN CHANCES FARTHER SOUTH AND LOWERED THEM TO A 20 TO 30 PERCENT CHANCES EXPECTING THE ACTIVITY TO PRIMARILY BE TO THE SOUTH OF THE AREA. ANY CONVECTION THAT FORMS TONIGHT SHOULD MOVE QUICKLY OFF TO THE EAST AS THE LOW LEVEL JET VEERS OFF TO THE SOUTHEAST. BY 12Z SUNDAY WOULD EXPECT ALL THE ACTIVITY TO BE OUT OF THE AREA SO HAVE REMOVED THE POPS FOR SUNDAY MORNING. AFTER THAT...THE WARM FRONT WILL CONTINUE TO LIFT NORTH MAKING IT INTO CENTRAL MINNESOTA AND WISCONSIN BY THE OF THE DAY. THE NAM AND 31.12Z GFS ARE IN GOOD AGREEMENT ON THE POSITION OF THE BAROCLINIC ZONE WITH 850 MB TEMPERATURES EXPECTED TO RANGE FROM ABOUT 10C ACROSS THE NORTH TO 17C IN THE SOUTHWEST. THE MIXING WILL NOT BE AS DEEP NORTH OF THE FRONT WHICH WILL KEEP SURFACE TEMPERATURES IN THE UPPER 60S THERE WHILE THE SOUTHWEST COULD SEE LOWER 80S WITH DEEPER MIXING. THE NEXT CHANCE FOR SOME RAIN LOOKS TO ARRIVE STARTING SUNDAY NIGHT AND CONTINUING THROUGH MONDAY NIGHT...ALTHOUGH THE MODELS ARE NOT IN VERY GOOD AGREEMENT ON HOW THIS WILL PLAY OUT. THE UPPER LEVEL RIDGE IS EXPECTED TO MOVE EAST OF THE AREA AS THE SYSTEM COMING INTO THE WEST COAST SPLITS OVER THE ROCKIES WITH ONE SHORT WAVE TROUGH TRACKING ACROSS SOUTHERN CANADA AND THE NORTHERN UPPER MIDWEST WITH A SECOND SHORT WAVE TROUGH FORMING A CUT OFF LOW AS IT DROPS INTO THE SOUTHERN PLAINS. THE GFS IS THE QUICKEST TO PUSH THE RIDGE OUT OF THE AREA AS IT RAPIDLY PROGRESSES THE NORTHERN STREAM SYSTEM ACROSS CANADA. AS A RESULT...IT PUSHES A SURFACE COLD FRONT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY AND MONDAY NIGHT. THE 31.00Z AND 31.12Z RUNS OF THE ECMWF WERE THE SLOWEST TO PUSH THE RIDGE OUT OF THE AREA SUGGESTING THIS MAY NOT OCCUR UNTIL MONDAY AFTERNOON OR NIGHT. THE NAM WAS SOMEWHAT IN THE MIDDLE OF THESE SOLUTIONS. ONE THING ALL THE MODELS DO AGREE ON IS THAT THE BEST FORCING WILL LIKELY SPLIT THE AREA WITH THE NORTHERN PARTS OF THE FORECAST AREA JUST GETTING BRUSHED WITH THE SOUTHERN EXTEND OF THE PV ADVECTION IN THE 500-300 MB LAYER AS THE NORTHERN STREAM SYSTEM PASSES BY. ONLY MADE SOME MINOR ADJUSTMENTS FORM THE ONGOING FORECAST BY GOING WITH A DRY FORECAST SUNDAY EVENING AND BRINGING IN A 20 PERCENT CHANCE ACROSS THE NORTH SUNDAY NIGHT. NO SUBSTANTIAL CHANGES TO MONDAY WITH 20 TO 30 PERCENT CHANCES FOR THE ENTIRE AREA AND THEN HELD WITH A 30 TO 50 PERCENT CHANCE FROM WEST TO EAST MONDAY NIGHT. IF THE SLOWER ECMWF SOLUTIONS PAN OUT...THESE RAIN CHANCES WILL BE TOO HIGH WITH THE POTENTIAL FOR RAIN JUST ACROSS THE WEST MONDAY AND PRIMARILY ACROSS THE NORTH MONDAY NIGHT. .LONG TERM...TUESDAY THROUGH SATURDAY 301 PM CDT SAT MAR 31 2012 THE FRONT SHOULD CLEAR THE AREA ALLOWING THE RAIN TO BE CONFINED TO AREAS EAST AND SOUTH OF THE REGION TUESDAY. AFTER THAT...HIGH PRESSURE BUILDS IN AND REMAINS THROUGH FRIDAY. MODELS SHOWING CONSIDERABLE VARIABILITY ON HOW FAST THE UPPER LEVEL RIDGE WILL BREAK DOWN ALLOWING THE NEXT SYSTEM TO COME IN. THE 31.12Z GFS BRINGS THIS SYSTEM IN FOR FRIDAY NIGHT AND SATURDAY WITH A COLD FRONT WORKING ACROSS THE ARA. HOWEVER...LOOKING BACK AT ITS PREVIOUS RUNS...IT HAS SHOWN NO CONTINUITY ON THE PLACEMENT OR TIMING OF THE UPPER LEVEL TROUGH. THE 31.00Z ECMWF HAD SHOWN THIS SYSTEM TO BE MUCH SLOWER REMAINING WEST OF THE AREA AND HAD GOOD CONTINUITY WITH ITS PREVIOUS RUNS. THE NEW 12Z RUN CAME IN MUCH QUICKER AND IN GOOD AGREEMENT WITH THE GFS. FOR NOW...WILL CARRY SOME LOW RAIN CHANCES WITH THIS SYSTEM FOR FRIDAY NIGHT AND SATURDAY. && .AVIATION...TONIGHT AND SUNDAY 659 PM CDT SAT MAR 31 2012 ANOTHER NIGHT OF STRATUS ACROSS MUCH OF EASTERN MINNESOTA AND IOWA...AND ALL OF WISCONSIN. MOSTLY A MIX OF MVFR CEILINGS ALONG THE MISSISSIPPI RIVER...WITH IFR CIGS/VISIBILITIES ALONG THE I-35 CORRIDOR IN MINNESOTA. LIGHT SOUTHEASTERLY FLOW OFF LAKE MICHIGAN HAS REALLY KEPT INVERSION IN PLACE TODAY. FOR THIS EVENING...THE RUC AND HRRR GUIDANCE SHOWS STATUS BREAKING UP AS SLIGHTLY DRIER AIR IS PULLED IN FROM THE SOUTHEAST AND THIS COULD POTENTIALLY LEAD TO CEILINGS RISING TO 2000 FT AT KRST AND 2500-3000 FT AT KLSE. HOWEVER...NOT A LOT OF CONFIDENCE IN THIS SCENARIO...BUT WILL HAVE TO MONITOR CLOSELY. AFTER MIDNIGHT...KEPT A LOWERING TREND TO IFR CEILINGS AT KRST AT 04Z AND 09Z AT KLSE. AS FOR FOG/LOW STRATUS POTENTIAL OVERNIGHT...THERE IS A SIMILAR SETUP TO LAST NIGHT. GIVEN PLENTIFUL LOW-LEVEL MOISTURE AND LIGHT WINDS...PLAN ON LOWERING CEILINGS/VISIBILITIES TO 400 FT/1SM AT KRST AND 900 FT/4SM AT KLSE. SINCE RECENT MODEL HANDLING OF FOG/STRATUS HAS BEEN POOR...PARTICULARLY WHEN TRYING TO LIFT/BREAK UP FOG THE MORNING AFTER...REMAINED PESSIMISTIC WITH ANY CLEARING TRENDS. BY AFTERNOON...INCREASING SOUTHEASTERLY WINDS SHOULD MIX UP TO BETWEEN 2000-3000 FT...HELPING TO BREAK UP LOW-LEVEL CLOUDS...AND GIVE WAY TO HIGH- LEVEL CLOUDS AROUND 15 KFT. && .ARX WATCHES/WARNINGS/ADVISORIES... 301 PM CDT SAT MAR 31 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1216 PM CDT FRI MAR 30 2012 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT 329 AM CDT FRI MAR 30 2012 MAIN FORECAST CONCERNS ARE ON CLOUDS THROUGH SATURDAY MORNING AS WELL AS TEMPERATURES THROUGHOUT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER THE NORTHEAST PACIFIC INTO SOUTHWEST CANADA...WEAK RIDGING OVER ONTARIO...THEN TROUGHING IN SOUTHEAST CANADA. SOUTH OF THE WEAK RIDGING...THERE WERE A FEW SHORTWAVES MOVING THROUGH A NEARLY ZONAL FLOW. THE FIRST AND MOST SIGNIFICANT ONE STRETCHED FROM NORTHEAST MINNESOTA INTO WESTERN IOWA. DPVA FROM THIS SHORTWAVE COMBINED WITH NUMEROUS OTHER FAVORABLE PRECIPITATION MECHANISMS WERE HELPING TO PRODUCE SHOWERS OVER MUCH OF THE FORECAST AREA. SOME OF THE MECHANISMS INCLUDE: RIGHT ENTRANCE REGION SUPPORT OF A 90-100 KT JET AT 200-225MB OVER NORTHERN WISCONSIN AND UPPER MICHIGAN PER RUC ANALYSIS...ISENTROPIC LIFT/WARM ADVECTION JUST NOTED FROM A 30-40 KT JET AT 850MB FROM LA CROSSE INTO NORTHERN MISSOURI PER PROFILER DATA...AND A MOISTURE STREAM INDICATED BY PRECIPITABLE WATER VALUES OF 0.75 TO 1.2 INCHES EXTENDING FROM THE FORECAST AREA SOUTHWEST INTO MISSOURI. SCATTERED THUNDERSTORMS HAVE ALSO OCCURRED...MAINLY SOUTH OF I-90 WHERE MUCAPE VALUES HAVE BEEN UP AROUND 300 J/KG. ALONG AND NORTH OF I-94 WHERE TEMPERATURES ARE IN THE LOW TO MID 30S...RESULTING FROM A COOLING AND DRYING EASTERLY FLOW...PRECIPITATION IN THE FORMS OF RAIN...SLEET AND SNOW HAVE OCCURRED. OTHER SHORTWAVES OF NOTE ON WATER VAPOR WITH MUCH LESS GOING ON WERE PRESENT OVER WESTERN SOUTH DAKOTA AND FROM NORTHWEST MINNESOTA INTO EASTERN MANITOBA. THE REASON FOR THE LACK OF ACTIVITY WITH THESE WAVES IS MID-LEVEL DRYING...SEEN ON THE 00Z BIS...UNR AND ABR SOUNDINGS. CLEARING LINE IS WELL OFF TO THE WEST...ALONG THE DAKOTAS/MINNESOTA BORDER. TODAY AND TONIGHT...CURRENT SHORTWAVE COMING INTO THE WESTERN PORTION OF THE FORECAST AREA IS PROGGED TO MOVE ACROSS THE AREA QUICKLY THIS MORNING...REACHING LAKE MICHIGAN BY 18Z. WITH THE FAST PROGRESSION OF THE SHORTWAVE...ANTICIPATING ALL PRECIPITATION TO END BY 15Z...AS PREVIOUS FORECASTS HAVE SUGGESTED. NEXT SHORTWAVE OVER WESTERN SOUTH DAKOTA FOLLOWS QUICKLY ON ITS HEELS...CROSSING THE FORECAST AREA LATE THIS AFTERNOON INTO THE EVENING...WITH WEAK UPPER RIDGING THEN BUILDING IN AFTER MIDNIGHT. GIVEN LACK OF ANY ACTIVITY UPSTREAM WITH THIS SHORTWAVE...ENVISION IT SHOULD COME THROUGH DRY. IN FACT...THE MORE PROBLEMATIC ISSUE THROUGH TONIGHT IS CLOUD COVER. SUBSIDENCE IN THE WAKE OF THIS MORNINGS SHORTWAVE...COMBINED WITH RECENT MOISTURE AND AN EASTERLY LOW LEVEL FLOW...ALL WOULD SUGGEST A CLOUDY-TYPE FORECAST IS THE WAY TO GO. DAYTIME MIXING SHOULD BE ABLE TO GRADUALLY BREAK UP CLOUDS SOMEWHAT WEST OF THE MISSISSIPPI RIVER THIS AFTERNOON. SOME HINTS THAT THIS CLEARING MAY SPREAD EAST INTO WISCONSIN AFTER MIDNIGHT TONIGHT...RESULTING FROM PERSISTENT SUBSIDENCE. ON THE OTHER HAND...CEILINGS COULD JUST LOWER INSTEAD. ANOTHER ISSUE...WITH THAT RIDGING MOVING IN LATER TONIGHT...WARM ADVECTION MID-CLOUDS LOOK TO RE-ENTER THE PICTURE...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. IN ADDITION...AM CONCERNED THAT LOW STRATUS COULD RE-DEVELOP WHERE SKIES CLEAR WEST OF THE MISSISSIPPI RIVER...RESULTING FROM RADIATIONAL COOLING AND AN UPSLOPING SOUTHEAST WIND DEVELOPING. GIVEN THE CLOUD CONCERNS...GENERALLY TOOK A BLEND OF ALL GUIDANCE FOR BOTH HIGHS AND LOWS. CONCERN DOES EXIST THAT CENTRAL WISCONSIN ZONES COULD SEE FROST TONIGHT...BUT CLOUD COVER ISSUES PRECLUDE ISSUING ANY ADVISORY AT THIS TIME. SATURDAY AND SATURDAY NIGHT...THE WEAK UPPER RIDGING BUILDING OVER THE AREA LATE FRIDAY NIGHT LOOKS TO CONTINUE INTO SATURDAY... RESPONDING TO A POTENT SHORTWAVE TRACKING INTO NORTHERN ONTARIO. UPPER RIDGING THEN RE-BUILDS BACK TO THE WEST OVER THE DAKOTAS RESULTING FROM A DEEP SHORTWAVE TROUGH MOVING THROUGH CALIFORNIA. DAYTIME MIXING IN CONJUNCTION WITH SUBSIDENCE UNDER THE WEAK UPPER RIDGE SHOULD HELP BUST UP ANY MORNING LOW LEVEL STRATUS. HOWEVER...BEING IN A WARM ADVECTION PATTERN AM CONCERNED THERE COULD BE SOME LOW/MID CLOUDS TO DEAL WITH. BOTH THE NAM/GFS SHOW THESE AROUND 800MB IN THE RH FIELDS...IN A NORTH-SOUTH BAND THAT MOVES WEST TO EAST ACROSS THE FORECAST AREA THROUGH THE DAY. IN FACT...IF YOU LIFT A PARCEL FROM 800MB IN THIS BAND...CAPE VALUES OF 300-500 J/KG ARE OBTAINABLE WITH NO CIN. ALTHOUGH NEITHER THE 30.00Z GFS...NAM OR REGIONAL CANADIAN PRODUCE ANY QPF FROM THIS BAND...FEEL COMPELLED TO HAVE SOME 20 PERCENT CHANCES. ACTUALLY...THE 30.00Z UKMET PRODUCES A LITTLE LIGHT QPF. ON SATURDAY NIGHT...ANOTHER SURGE OF ISENTROPIC LIFT NOTED ON 295-305K SURFACES IS PROGGED TO MOVE INTO/THROUGH THE AREA. THE UKMET IS BY FAR THE MOST BULLISH WITH CONVECTION...THOUGH THE HEAVIEST PORTION IS CENTERED OVER NORTHERN ILLINOIS. THE 30.00Z GFS/NAM BOTH DEVELOP CONVECTION...MAINLY OVER THE SOUTHEAST HALF BETWEEN 06-12Z SUNDAY. EITHER WAY...SOME PRECIPITATION CHANCES ARE WARRANTED...WHICH HAVE BEEN RAISED ABOUT 10 PERCENT FROM THE PREVIOUS FORECAST. WITH MORE CLOUDS TO DEAL WITH ON SATURDAY AND 925MB TEMPS ONLY REACHING 10-14C BY 00Z...LOWERED HIGHS 3-4 DEGREES. CONTINUOUS WARM ADVECTION THROUGH MUCH OF SATURDAY NIGHT SHOULD HELP TO KEEP TEMPERATURES UP AND PREVIOUS FORECAST LOWS SEEM REASONABLE. SUNDAY AND SUNDAY NIGHT...UPPER RIDGING OVER THE NORTHERN PLAINS IS EXPECTED TO GRADUALLY SHIFT EAST...MOVING OVER THE FORECAST AREA SUNDAY NIGHT. AGAIN...THIS IN RESPONSE TO THE DEEP TROUGHING OVER THE WESTERN U.S. SLOWLY MOVING EAST. THIS UPPER RIDGE IS STRONGER THAN THE PREVIOUS COUPLE ONES MOVING THROUGH...SO ITS SUBSIDENCE SHOULD BE STRONGER. INDEED...MOST MODELS KEEP THE FORECAST AREA DRY THROUGH SUNDAY NIGHT AND HAVE TRENDED THE FORECAST IN THIS DIRECTION. THIS LEAVES TEMPERATURES THE BIGGER ISSUE. WITH A MORE AMPLIFIED LOOK TO THE UPPER RIDGING...THAT WARM FRONT MENTIONED IN PREVIOUS DISCUSSIONS TO COME THROUGH ON SUNDAY MAY END UP STAYING ALONG OR SOUTH OF I-90. IN FACT...THE 30.00Z GFS/UKMET HINT AT BACKDOOR COLD FRONT POTENTIAL. STILL...IT SEEMS LIKE A SOLID BET FOR SUNDAY TO END UP QUITE A BIT WARMER THAN SATURDAY...ESPECIALLY WEST OF THE MISSISSIPPI RIVER WHERE 925MB TEMPERATURE CONSENSUS SUGGESTS READINGS OF 20-22C. CLOSER TO CENTRAL WISCONSIN...14-16C READINGS SHOULD BE MORE COMMON. WITH THE COOLER TREND NOTED IN MODELS...DID KNOCK HIGHS BACK A FEW DEGREES OVER WISCONSIN AREAS. FURTHER LOWERING MAY BE REQUIRED DEPENDING ON THE BACKDOOR COLD FRONT POTENTIAL. WARM AIR SHOULD HOLD IN HERE SUNDAY NIGHT...IN COMBINATION WITH THE UPPER RIDGE AND WITH A LOW PRESSURE SYSTEM TRYING TO APPROACH THE AREA FROM THE CENTRAL PLAINS. PREVIOUS LOW TEMPERATURE FORECAST LOOKS ON TRACK. .LONG TERM...MONDAY THROUGH THURSDAY NIGHT 329 AM CDT FRI MAR 30 2012 TREND IN THE RECENT 30.00Z GFS/ECMWF/UKMET/CANADIAN IS TO SUGGEST THAT THE WESTERN TROUGHING IS GOING TO SPLIT INTO TWO. THE SOUTHERN END CUTS OFF OVER TEXAS FOR MUCH OF THE LONG TERM PERIOD...WHILE THE NORTHERN END COMES THROUGH THE FORECAST AREA ON TUESDAY. THIS IS SLOWER THAN PREVIOUSLY FORECAST...AND IN FACT IF THE 30.00Z ECMWF IS CORRECT...MONDAY COULD BE A VERY WARM AND EVEN HUMID DAY ACROSS MUCH OF THE FORECAST AREA. SUGGESTION FROM THE MODEL IS HIGHS IN THE LOW 80S AND DEWPOINTS IN THE LOW 60S...ALL FROM THE LOW PRESSURE SYSTEM IN THE CENTRAL PLAINS LIFTING NORTHEAST INTO NORTHWEST WISCONSIN. HAVE NOT JUMPED ON THIS SCENARIO QUITE YET...SINCE MOST MODELS KEEP THIS SYSTEM TO THE SOUTH OF THE AREA...BUT DEFINITELY WARRANTS WATCHING. ALSO THE ECMWF WOULD SUGGEST SOME STRONG CONVECTION AT LEAST AS THE COLD FRONT COMES THROUGH. NEEDLESS TO SAY...CHANCES OF PRECIPITATION CONTINUE IN THE FORECAST FOR MONDAY INTO MONDAY NIGHT...MAINLY IN THE 20-40 RANGE UNTIL THIS WHOLE SYSTEM CAN BE IRONED OUT. DRYING TREND THEN IS FORECAST FOR TUESDAY AND CONTINUING THROUGH THE REST OF THE LONG TERM PERIOD WITH MOST MODELS AND ENSEMBLES SHOWING NORTHWEST FLOW OVER THE FORECAST AREA. DID KEEP A 20 PERCENT CHANCE OF SHOWERS GOING ON TUESDAY WITH THE UPPER TROUGH MOVING THROUGH...THOUGH. HOW MUCH NORTHWEST FLOW AND THE COLD AIR ASSOCIATED WITH IT VARIES...SO FOR NOW STAYED WITH A BLEND OF MODELS FOR TEMPERATURES. READINGS STILL LOOK TO STAY ABOVE NORMAL AS HIGHS ONLY DROP INTO THE MID TO UPPER 50S AT THE LOWEST. NORMAL HIGHS ARE IN THE LOW 50S. && .AVIATION...THROUGH 18Z SATURDAY 1216 PM CDT FRI MAR 30 2012 VISIBLE SATELLITE SHOWING A LARGE AREA OF IFR/MVFR CLOUDS COVERING MUCH OF THE UPPER MIDWEST. LOOKING AT THE 30.12Z NAM...NOT EXPECTING THESE CLOUDS TO DISSIPATE ANYTIME SOON AS THE RELATIVE HUMIDITY AT 925 MB IS EXPECTED TO STAY HIGH INTO SATURDAY MORNING. THE CONCERN IS WHETHER THERE WILL BE ANY BREAK IN THE CLOUDS THIS EVENING. THE NAM BUFKIT SOUNDINGS WOULD SUGGEST THE LOW CLOUDS BREAKING UP FOR A WHILE THIS EVENING AS DOES THE 30.12Z HRRR BEFORE THEY REFORM OVERNIGHT. THE WESTERN EDGE OF THE CLOUDS ACROSS WESTERN MINNESOTA AND IOWA DO SHOW SIGNS OF BREAKING UP BUT NOT SURE IF THIS WILL BE ABLE TO WORK EAST INTO THE AREA GIVEN THE LIGHT FLOW IN THE LOW LEVELS. FOR NOW...WILL CONTINUE THE TRENDS OF KEEPING THE CLOUDS IN THROUGH THE EVENING AND THEN LOWERING THEM BACK TO IFR OVERNIGHT WITH SOME COOLING. WILL NOT INCLUDE ANY FOG OVERNIGHT AT EITHER SITE AS THE WINDS SHOULD BE INCREASING OUT OF THE SOUTHEAST AS AN AREA OF HIGH PRESSURE MOVES OFF TO THE EAST AND THE NEXT FRONT MOVES INTO THE DAKOTAS. && .HYDROLOGY... 329 AM CDT FRI MAR 30 2012 AS OF 3 AM...MAJORITY OF THE PRECIPITATION SO FAR HAS FALLEN ALONG AND SOUTH OF A LINE FROM ST ANSGAR IOWA TO WINONA MN AND BLACK RIVER FALLS WISCONSIN. RADAR ESTIMATES SHOW THAT THE SHOWERS AND THUNDERSTORMS PRODUCED AMOUNTS RANGING FROM 0.25 TO 0.75 INCHES. HOWEVER...THERE IS AN AREA COVERING SOUTHEAST FAYETTE...MUCH OF CLAYTON AND NORTHERN GRANT COUNTIES WHERE 0.75 TO 1.75 INCHES FELL...HIGHEST NEAR STRAWBERRY POINT. NO REPORTS OF ANY FLOODING THUS FAR BUT EXPECT SOME BRIEF RISES IN SMALL STREAMS. WILL HAVE TO KEEP AN EYE ON THE TURKEY RIVER...THOUGH THE LACK OF SIGNIFICANT RAINFALL AND GENERALLY DRY SOILS SHOULD KEEP THE RIVER BELOW FLOOD STAGE. && .ARX WATCHES/WARNINGS/ADVISORIES... 328 AM CDT FRI MAR 30 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...04 HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
615 AM CDT FRI MAR 30 2012 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT 329 AM CDT FRI MAR 30 2012 MAIN FORECAST CONCERNS ARE ON CLOUDS THROUGH SATURDAY MORNING AS WELL AS TEMPERATURES THROUGHOUT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER THE NORTHEAST PACIFIC INTO SOUTHWEST CANADA...WEAK RIDGING OVER ONTARIO...THEN TROUGHING IN SOUTHEAST CANADA. SOUTH OF THE WEAK RIDGING...THERE WERE A FEW SHORTWAVES MOVING THROUGH A NEARLY ZONAL FLOW. THE FIRST AND MOST SIGNIFICANT ONE STRETCHED FROM NORTHEAST MINNESOTA INTO WESTERN IOWA. DPVA FROM THIS SHORTWAVE COMBINED WITH NUMEROUS OTHER FAVORABLE PRECIPITATION MECHANISMS WERE HELPING TO PRODUCE SHOWERS OVER MUCH OF THE FORECAST AREA. SOME OF THE MECHANISMS INCLUDE: RIGHT ENTRANCE REGION SUPPORT OF A 90-100 KT JET AT 200-225MB OVER NORTHERN WISCONSIN AND UPPER MICHIGAN PER RUC ANALYSIS...ISENTROPIC LIFT/WARM ADVECTION JUST NOTED FROM A 30-40 KT JET AT 850MB FROM LA CROSSE INTO NORTHERN MISSOURI PER PROFILER DATA...AND A MOISTURE STREAM INDICATED BY PRECIPITABLE WATER VALUES OF 0.75 TO 1.2 INCHES EXTENDING FROM THE FORECAST AREA SOUTHWEST INTO MISSOURI. SCATTERED THUNDERSTORMS HAVE ALSO OCCURRED...MAINLY SOUTH OF I-90 WHERE MUCAPE VALUES HAVE BEEN UP AROUND 300 J/KG. ALONG AND NORTH OF I-94 WHERE TEMPERATURES ARE IN THE LOW TO MID 30S...RESULTING FROM A COOLING AND DRYING EASTERLY FLOW...PRECIPITATION IN THE FORMS OF RAIN...SLEET AND SNOW HAVE OCCURRED. OTHER SHORTWAVES OF NOTE ON WATER VAPOR WITH MUCH LESS GOING ON WERE PRESENT OVER WESTERN SOUTH DAKOTA AND FROM NORTHWEST MINNESOTA INTO EASTERN MANITOBA. THE REASON FOR THE LACK OF ACTIVITY WITH THESE WAVES IS MID-LEVEL DRYING...SEEN ON THE 00Z BIS...UNR AND ABR SOUNDINGS. CLEARING LINE IS WELL OFF TO THE WEST...ALONG THE DAKOTAS/MINNESOTA BORDER. TODAY AND TONIGHT...CURRENT SHORTWAVE COMING INTO THE WESTERN PORTION OF THE FORECAST AREA IS PROGGED TO MOVE ACROSS THE AREA QUICKLY THIS MORNING...REACHING LAKE MICHIGAN BY 18Z. WITH THE FAST PROGRESSION OF THE SHORTWAVE...ANTICIPATING ALL PRECIPITATION TO END BY 15Z...AS PREVIOUS FORECASTS HAVE SUGGESTED. NEXT SHORTWAVE OVER WESTERN SOUTH DAKOTA FOLLOWS QUICKLY ON ITS HEELS...CROSSING THE FORECAST AREA LATE THIS AFTERNOON INTO THE EVENING...WITH WEAK UPPER RIDGING THEN BUILDING IN AFTER MIDNIGHT. GIVEN LACK OF ANY ACTIVITY UPSTREAM WITH THIS SHORTWAVE...ENVISION IT SHOULD COME THROUGH DRY. IN FACT...THE MORE PROBLEMATIC ISSUE THROUGH TONIGHT IS CLOUD COVER. SUBSIDENCE IN THE WAKE OF THIS MORNINGS SHORTWAVE...COMBINED WITH RECENT MOISTURE AND AN EASTERLY LOW LEVEL FLOW...ALL WOULD SUGGEST A CLOUDY-TYPE FORECAST IS THE WAY TO GO. DAYTIME MIXING SHOULD BE ABLE TO GRADUALLY BREAK UP CLOUDS SOMEWHAT WEST OF THE MISSISSIPPI RIVER THIS AFTERNOON. SOME HINTS THAT THIS CLEARING MAY SPREAD EAST INTO WISCONSIN AFTER MIDNIGHT TONIGHT...RESULTING FROM PERSISTENT SUBSIDENCE. ON THE OTHER HAND...CEILINGS COULD JUST LOWER INSTEAD. ANOTHER ISSUE...WITH THAT RIDGING MOVING IN LATER TONIGHT...WARM ADVECTION MID-CLOUDS LOOK TO RE-ENTER THE PICTURE...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. IN ADDITION...AM CONCERNED THAT LOW STRATUS COULD RE-DEVELOP WHERE SKIES CLEAR WEST OF THE MISSISSIPPI RIVER...RESULTING FROM RADIATIONAL COOLING AND AN UPSLOPING SOUTHEAST WIND DEVELOPING. GIVEN THE CLOUD CONCERNS...GENERALLY TOOK A BLEND OF ALL GUIDANCE FOR BOTH HIGHS AND LOWS. CONCERN DOES EXIST THAT CENTRAL WISCONSIN ZONES COULD SEE FROST TONIGHT...BUT CLOUD COVER ISSUES PRECLUDE ISSUING ANY ADVISORY AT THIS TIME. SATURDAY AND SATURDAY NIGHT...THE WEAK UPPER RIDGING BUILDING OVER THE AREA LATE FRIDAY NIGHT LOOKS TO CONTINUE INTO SATURDAY... RESPONDING TO A POTENT SHORTWAVE TRACKING INTO NORTHERN ONTARIO. UPPER RIDGING THEN RE-BUILDS BACK TO THE WEST OVER THE DAKOTAS RESULTING FROM A DEEP SHORTWAVE TROUGH MOVING THROUGH CALIFORNIA. DAYTIME MIXING IN CONJUNCTION WITH SUBSIDENCE UNDER THE WEAK UPPER RIDGE SHOULD HELP BUST UP ANY MORNING LOW LEVEL STRATUS. HOWEVER...BEING IN A WARM ADVECTION PATTERN AM CONCERNED THERE COULD BE SOME LOW/MID CLOUDS TO DEAL WITH. BOTH THE NAM/GFS SHOW THESE AROUND 800MB IN THE RH FIELDS...IN A NORTH-SOUTH BAND THAT MOVES WEST TO EAST ACROSS THE FORECAST AREA THROUGH THE DAY. IN FACT...IF YOU LIFT A PARCEL FROM 800MB IN THIS BAND...CAPE VALUES OF 300-500 J/KG ARE OBTAINABLE WITH NO CIN. ALTHOUGH NEITHER THE 30.00Z GFS...NAM OR REGIONAL CANADIAN PRODUCE ANY QPF FROM THIS BAND...FEEL COMPELLED TO HAVE SOME 20 PERCENT CHANCES. ACTUALLY...THE 30.00Z UKMET PRODUCES A LITTLE LIGHT QPF. ON SATURDAY NIGHT...ANOTHER SURGE OF ISENTROPIC LIFT NOTED ON 295-305K SURFACES IS PROGGED TO MOVE INTO/THROUGH THE AREA. THE UKMET IS BY FAR THE MOST BULLISH WITH CONVECTION...THOUGH THE HEAVIEST PORTION IS CENTERED OVER NORTHERN ILLINOIS. THE 30.00Z GFS/NAM BOTH DEVELOP CONVECTION...MAINLY OVER THE SOUTHEAST HALF BETWEEN 06-12Z SUNDAY. EITHER WAY...SOME PRECIPITATION CHANCES ARE WARRANTED...WHICH HAVE BEEN RAISED ABOUT 10 PERCENT FROM THE PREVIOUS FORECAST. WITH MORE CLOUDS TO DEAL WITH ON SATURDAY AND 925MB TEMPS ONLY REACHING 10-14C BY 00Z...LOWERED HIGHS 3-4 DEGREES. CONTINUOUS WARM ADVECTION THROUGH MUCH OF SATURDAY NIGHT SHOULD HELP TO KEEP TEMPERATURES UP AND PREVIOUS FORECAST LOWS SEEM REASONABLE. SUNDAY AND SUNDAY NIGHT...UPPER RIDGING OVER THE NORTHERN PLAINS IS EXPECTED TO GRADUALLY SHIFT EAST...MOVING OVER THE FORECAST AREA SUNDAY NIGHT. AGAIN...THIS IN RESPONSE TO THE DEEP TROUGHING OVER THE WESTERN U.S. SLOWLY MOVING EAST. THIS UPPER RIDGE IS STRONGER THAN THE PREVIOUS COUPLE ONES MOVING THROUGH...SO ITS SUBSIDENCE SHOULD BE STRONGER. INDEED...MOST MODELS KEEP THE FORECAST AREA DRY THROUGH SUNDAY NIGHT AND HAVE TRENDED THE FORECAST IN THIS DIRECTION. THIS LEAVES TEMPERATURES THE BIGGER ISSUE. WITH A MORE AMPLIFIED LOOK TO THE UPPER RIDGING...THAT WARM FRONT MENTIONED IN PREVIOUS DISCUSSIONS TO COME THROUGH ON SUNDAY MAY END UP STAYING ALONG OR SOUTH OF I-90. IN FACT...THE 30.00Z GFS/UKMET HINT AT BACKDOOR COLD FRONT POTENTIAL. STILL...IT SEEMS LIKE A SOLID BET FOR SUNDAY TO END UP QUITE A BIT WARMER THAN SATURDAY...ESPECIALLY WEST OF THE MISSISSIPPI RIVER WHERE 925MB TEMPERATURE CONSENSUS SUGGESTS READINGS OF 20-22C. CLOSER TO CENTRAL WISCONSIN...14-16C READINGS SHOULD BE MORE COMMON. WITH THE COOLER TREND NOTED IN MODELS...DID KNOCK HIGHS BACK A FEW DEGREES OVER WISCONSIN AREAS. FURTHER LOWERING MAY BE REQUIRED DEPENDING ON THE BACKDOOR COLD FRONT POTENTIAL. WARM AIR SHOULD HOLD IN HERE SUNDAY NIGHT...IN COMBINATION WITH THE UPPER RIDGE AND WITH A LOW PRESSURE SYSTEM TRYING TO APPROACH THE AREA FROM THE CENTRAL PLAINS. PREVIOUS LOW TEMPERATURE FORECAST LOOKS ON TRACK. .LONG TERM...MONDAY THROUGH THURSDAY NIGHT 329 AM CDT FRI MAR 30 2012 TREND IN THE RECENT 30.00Z GFS/ECMWF/UKMET/CANADIAN IS TO SUGGEST THAT THE WESTERN TROUGHING IS GOING TO SPLIT INTO TWO. THE SOUTHERN END CUTS OFF OVER TEXAS FOR MUCH OF THE LONG TERM PERIOD...WHILE THE NORTHERN END COMES THROUGH THE FORECAST AREA ON TUESDAY. THIS IS SLOWER THAN PREVIOUSLY FORECAST...AND IN FACT IF THE 30.00Z ECMWF IS CORRECT...MONDAY COULD BE A VERY WARM AND EVEN HUMID DAY ACROSS MUCH OF THE FORECAST AREA. SUGGESTION FROM THE MODEL IS HIGHS IN THE LOW 80S AND DEWPOINTS IN THE LOW 60S...ALL FROM THE LOW PRESSURE SYSTEM IN THE CENTRAL PLAINS LIFTING NORTHEAST INTO NORTHWEST WISCONSIN. HAVE NOT JUMPED ON THIS SCENARIO QUITE YET...SINCE MOST MODELS KEEP THIS SYSTEM TO THE SOUTH OF THE AREA...BUT DEFINITELY WARRANTS WATCHING. ALSO THE ECMWF WOULD SUGGEST SOME STRONG CONVECTION AT LEAST AS THE COLD FRONT COMES THROUGH. NEEDLESS TO SAY...CHANCES OF PRECIPITATION CONTINUE IN THE FORECAST FOR MONDAY INTO MONDAY NIGHT...MAINLY IN THE 20-40 RANGE UNTIL THIS WHOLE SYSTEM CAN BE IRONED OUT. DRYING TREND THEN IS FORECAST FOR TUESDAY AND CONTINUING THROUGH THE REST OF THE LONG TERM PERIOD WITH MOST MODELS AND ENSEMBLES SHOWING NORTHWEST FLOW OVER THE FORECAST AREA. DID KEEP A 20 PERCENT CHANCE OF SHOWERS GOING ON TUESDAY WITH THE UPPER TROUGH MOVING THROUGH...THOUGH. HOW MUCH NORTHWEST FLOW AND THE COLD AIR ASSOCIATED WITH IT VARIES...SO FOR NOW STAYED WITH A BLEND OF MODELS FOR TEMPERATURES. READINGS STILL LOOK TO STAY ABOVE NORMAL AS HIGHS ONLY DROP INTO THE MID TO UPPER 50S AT THE LOWEST. NORMAL HIGHS ARE IN THE LOW 50S. && .AVIATION...TODAY AND TONIGHT 615 AM CDT FRI MAR 30 2012 PLAN ON IFR CONDITIONS IN LOW STRATUS AT THE TAF SITES THROUGH MID MORNING. LOOK FOR CEILINGS IN THE 600 TO 900 FT RANGE. IN ADDITION...VISIBILITIES WILL BE REDUCED TO AROUND 5 SM IN BR. THE LOW STRATUS SHOULD LIFT INTO AN MVFR STRATUS DECK THIS AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE AREA WITH HIGH PRESSURE ATTEMPTING TO BUILD IN FROM THE NORTHEAST. CLOUD BASES ARE EXPECTED TO RISE TO AROUND 2 KFT BY EARLY THIS AFTERNOON...AND POSSIBLY INCREASING TO AROUND 3500 FT IN THE 22Z-00Z TIMEFRAME. FORECAST SOUNDINGS ARE SHOWING THE STRATUS LOWERING AGAIN TONIGHT INTO THE IFR CATEGORY. THE INCREASING PRESSURE GRADIENT SHOULD KEEP WINDS JUST ABOVE THE SURFACE IN THE 10 TO 15 KT RANGE...PREVENTING FOG DEVELOPMENT. PLAN ON CEILINGS LOWERING INTO THE 600 TO 900 FT RANGE AGAIN LATE THIS EVENING AND PERSISTING THROUGH THE OVERNIGHT HOURS. IF LESS WIND IS REALIZED...FOG WILL BE POSSIBLE ESPECIALLY AT KLSE WHERE DECOUPLING COULD OCCUR. && .HYDROLOGY... 329 AM CDT FRI MAR 30 2012 AS OF 3 AM...MAJORITY OF THE PRECIPITATION SO FAR HAS FALLEN ALONG AND SOUTH OF A LINE FROM ST ANSGAR IOWA TO WINONA MN AND BLACK RIVER FALLS WISCONSIN. RADAR ESTIMATES SHOW THAT THE SHOWERS AND THUNDERSTORMS PRODUCED AMOUNTS RANGING FROM 0.25 TO 0.75 INCHES. HOWEVER...THERE IS AN AREA COVERING SOUTHEAST FAYETTE...MUCH OF CLAYTON AND NORTHERN GRANT COUNTIES WHERE 0.75 TO 1.75 INCHES FELL...HIGHEST NEAR STRAWBERRY POINT. NO REPORTS OF ANY FLOODING THUS FAR BUT EXPECT SOME BRIEF RISES IN SMALL STREAMS. WILL HAVE TO KEEP AN EYE ON THE TURKEY RIVER...THOUGH THE LACK OF SIGNIFICANT RAINFALL AND GENERALLY DRY SOILS SHOULD KEEP THE RIVER BELOW FLOOD STAGE. && .ARX WATCHES/WARNINGS/ADVISORIES... 328 AM CDT FRI MAR 30 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 AM CDT FRI MAR 30 2012 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT 329 AM CDT FRI MAR 30 2012 MAIN FORECAST CONCERNS ARE ON CLOUDS THROUGH SATURDAY MORNING AS WELL AS TEMPERATURES THROUGHOUT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER THE NORTHEAST PACIFIC INTO SOUTHWEST CANADA...WEAK RIDGING OVER ONTARIO...THEN TROUGHING IN SOUTHEAST CANADA. SOUTH OF THE WEAK RIDGING...THERE WERE A FEW SHORTWAVES MOVING THROUGH A NEARLY ZONAL FLOW. THE FIRST AND MOST SIGNIFICANT ONE STRETCHED FROM NORTHEAST MINNESOTA INTO WESTERN IOWA. DPVA FROM THIS SHORTWAVE COMBINED WITH NUMEROUS OTHER FAVORABLE PRECIPITATION MECHANISMS WERE HELPING TO PRODUCE SHOWERS OVER MUCH OF THE FORECAST AREA. SOME OF THE MECHANISMS INCLUDE: RIGHT ENTRANCE REGION SUPPORT OF A 90-100 KT JET AT 200-225MB OVER NORTHERN WISCONSIN AND UPPER MICHIGAN PER RUC ANALYSIS...ISENTROPIC LIFT/WARM ADVECTION JUST NOTED FROM A 30-40 KT JET AT 850MB FROM LA CROSSE INTO NORTHERN MISSOURI PER PROFILER DATA...AND A MOISTURE STREAM INDICATED BY PRECIPITABLE WATER VALUES OF 0.75 TO 1.2 INCHES EXTENDING FROM THE FORECAST AREA SOUTHWEST INTO MISSOURI. SCATTERED THUNDERSTORMS HAVE ALSO OCCURRED...MAINLY SOUTH OF I-90 WHERE MUCAPE VALUES HAVE BEEN UP AROUND 300 J/KG. ALONG AND NORTH OF I-94 WHERE TEMPERATURES ARE IN THE LOW TO MID 30S...RESULTING FROM A COOLING AND DRYING EASTERLY FLOW...PRECIPITATION IN THE FORMS OF RAIN...SLEET AND SNOW HAVE OCCURRED. OTHER SHORTWAVES OF NOTE ON WATER VAPOR WITH MUCH LESS GOING ON WERE PRESENT OVER WESTERN SOUTH DAKOTA AND FROM NORTHWEST MINNESOTA INTO EASTERN MANITOBA. THE REASON FOR THE LACK OF ACTIVITY WITH THESE WAVES IS MID-LEVEL DRYING...SEEN ON THE 00Z BIS...UNR AND ABR SOUNDINGS. CLEARING LINE IS WELL OFF TO THE WEST...ALONG THE DAKOTAS/MINNESOTA BORDER. TODAY AND TONIGHT...CURRENT SHORTWAVE COMING INTO THE WESTERN PORTION OF THE FORECAST AREA IS PROGGED TO MOVE ACROSS THE AREA QUICKLY THIS MORNING...REACHING LAKE MICHIGAN BY 18Z. WITH THE FAST PROGRESSION OF THE SHORTWAVE...ANTICIPATING ALL PRECIPITATION TO END BY 15Z...AS PREVIOUS FORECASTS HAVE SUGGESTED. NEXT SHORTWAVE OVER WESTERN SOUTH DAKOTA FOLLOWS QUICKLY ON ITS HEELS...CROSSING THE FORECAST AREA LATE THIS AFTERNOON INTO THE EVENING...WITH WEAK UPPER RIDGING THEN BUILDING IN AFTER MIDNIGHT. GIVEN LACK OF ANY ACTIVITY UPSTREAM WITH THIS SHORTWAVE...ENVISION IT SHOULD COME THROUGH DRY. IN FACT...THE MORE PROBLEMATIC ISSUE THROUGH TONIGHT IS CLOUD COVER. SUBSIDENCE IN THE WAKE OF THIS MORNINGS SHORTWAVE...COMBINED WITH RECENT MOISTURE AND AN EASTERLY LOW LEVEL FLOW...ALL WOULD SUGGEST A CLOUDY-TYPE FORECAST IS THE WAY TO GO. DAYTIME MIXING SHOULD BE ABLE TO GRADUALLY BREAK UP CLOUDS SOMEWHAT WEST OF THE MISSISSIPPI RIVER THIS AFTERNOON. SOME HINTS THAT THIS CLEARING MAY SPREAD EAST INTO WISCONSIN AFTER MIDNIGHT TONIGHT...RESULTING FROM PERSISTENT SUBSIDENCE. ON THE OTHER HAND...CEILINGS COULD JUST LOWER INSTEAD. ANOTHER ISSUE...WITH THAT RIDGING MOVING IN LATER TONIGHT...WARM ADVECTION MID-CLOUDS LOOK TO RE-ENTER THE PICTURE...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. IN ADDITION...AM CONCERNED THAT LOW STRATUS COULD RE-DEVELOP WHERE SKIES CLEAR WEST OF THE MISSISSIPPI RIVER...RESULTING FROM RADIATIONAL COOLING AND AN UPSLOPING SOUTHEAST WIND DEVELOPING. GIVEN THE CLOUD CONCERNS...GENERALLY TOOK A BLEND OF ALL GUIDANCE FOR BOTH HIGHS AND LOWS. CONCERN DOES EXIST THAT CENTRAL WISCONSIN ZONES COULD SEE FROST TONIGHT...BUT CLOUD COVER ISSUES PRECLUDE ISSUING ANY ADVISORY AT THIS TIME. SATURDAY AND SATURDAY NIGHT...THE WEAK UPPER RIDGING BUILDING OVER THE AREA LATE FRIDAY NIGHT LOOKS TO CONTINUE INTO SATURDAY... RESPONDING TO A POTENT SHORTWAVE TRACKING INTO NORTHERN ONTARIO. UPPER RIDGING THEN RE-BUILDS BACK TO THE WEST OVER THE DAKOTAS RESULTING FROM A DEEP SHORTWAVE TROUGH MOVING THROUGH CALIFORNIA. DAYTIME MIXING IN CONJUNCTION WITH SUBSIDENCE UNDER THE WEAK UPPER RIDGE SHOULD HELP BUST UP ANY MORNING LOW LEVEL STRATUS. HOWEVER...BEING IN A WARM ADVECTION PATTERN AM CONCERNED THERE COULD BE SOME LOW/MID CLOUDS TO DEAL WITH. BOTH THE NAM/GFS SHOW THESE AROUND 800MB IN THE RH FIELDS...IN A NORTH-SOUTH BAND THAT MOVES WEST TO EAST ACROSS THE FORECAST AREA THROUGH THE DAY. IN FACT...IF YOU LIFT A PARCEL FROM 800MB IN THIS BAND...CAPE VALUES OF 300-500 J/KG ARE OBTAINABLE WITH NO CIN. ALTHOUGH NEITHER THE 30.00Z GFS...NAM OR REGIONAL CANADIAN PRODUCE ANY QPF FROM THIS BAND...FEEL COMPELLED TO HAVE SOME 20 PERCENT CHANCES. ACTUALLY...THE 30.00Z UKMET PRODUCES A LITTLE LIGHT QPF. ON SATURDAY NIGHT...ANOTHER SURGE OF ISENTROPIC LIFT NOTED ON 295-305K SURFACES IS PROGGED TO MOVE INTO/THROUGH THE AREA. THE UKMET IS BY FAR THE MOST BULLISH WITH CONVECTION...THOUGH THE HEAVIEST PORTION IS CENTERED OVER NORTHERN ILLINOIS. THE 30.00Z GFS/NAM BOTH DEVELOP CONVECTION...MAINLY OVER THE SOUTHEAST HALF BETWEEN 06-12Z SUNDAY. EITHER WAY...SOME PRECIPITATION CHANCES ARE WARRANTED...WHICH HAVE BEEN RAISED ABOUT 10 PERCENT FROM THE PREVIOUS FORECAST. WITH MORE CLOUDS TO DEAL WITH ON SATURDAY AND 925MB TEMPS ONLY REACHING 10-14C BY 00Z...LOWERED HIGHS 3-4 DEGREES. CONTINUOUS WARM ADVECTION THROUGH MUCH OF SATURDAY NIGHT SHOULD HELP TO KEEP TEMPERATURES UP AND PREVIOUS FORECAST LOWS SEEM REASONABLE. SUNDAY AND SUNDAY NIGHT...UPPER RIDGING OVER THE NORTHERN PLAINS IS EXPECTED TO GRADUALLY SHIFT EAST...MOVING OVER THE FORECAST AREA SUNDAY NIGHT. AGAIN...THIS IN RESPONSE TO THE DEEP TROUGHING OVER THE WESTERN U.S. SLOWLY MOVING EAST. THIS UPPER RIDGE IS STRONGER THAN THE PREVIOUS COUPLE ONES MOVING THROUGH...SO ITS SUBSIDENCE SHOULD BE STRONGER. INDEED...MOST MODELS KEEP THE FORECAST AREA DRY THROUGH SUNDAY NIGHT AND HAVE TRENDED THE FORECAST IN THIS DIRECTION. THIS LEAVES TEMPERATURES THE BIGGER ISSUE. WITH A MORE AMPLIFIED LOOK TO THE UPPER RIDGING...THAT WARM FRONT MENTIONED IN PREVIOUS DISCUSSIONS TO COME THROUGH ON SUNDAY MAY END UP STAYING ALONG OR SOUTH OF I-90. IN FACT...THE 30.00Z GFS/UKMET HINT AT BACKDOOR COLD FRONT POTENTIAL. STILL...IT SEEMS LIKE A SOLID BET FOR SUNDAY TO END UP QUITE A BIT WARMER THAN SATURDAY...ESPECIALLY WEST OF THE MISSISSIPPI RIVER WHERE 925MB TEMPERATURE CONSENSUS SUGGESTS READINGS OF 20-22C. CLOSER TO CENTRAL WISCONSIN...14-16C READINGS SHOULD BE MORE COMMON. WITH THE COOLER TREND NOTED IN MODELS...DID KNOCK HIGHS BACK A FEW DEGREES OVER WISCONSIN AREAS. FURTHER LOWERING MAY BE REQUIRED DEPENDING ON THE BACKDOOR COLD FRONT POTENTIAL. WARM AIR SHOULD HOLD IN HERE SUNDAY NIGHT...IN COMBINATION WITH THE UPPER RIDGE AND WITH A LOW PRESSURE SYSTEM TRYING TO APPROACH THE AREA FROM THE CENTRAL PLAINS. PREVIOUS LOW TEMPERATURE FORECAST LOOKS ON TRACK. .LONG TERM...MONDAY THROUGH THURSDAY NIGHT 329 AM CDT FRI MAR 30 2012 TREND IN THE RECENT 30.00Z GFS/ECMWF/UKMET/CANADIAN IS TO SUGGEST THAT THE WESTERN TROUGHING IS GOING TO SPLIT INTO TWO. THE SOUTHERN END CUTS OFF OVER TEXAS FOR MUCH OF THE LONG TERM PERIOD...WHILE THE NORTHERN END COMES THROUGH THE FORECAST AREA ON TUESDAY. THIS IS SLOWER THAN PREVIOUSLY FORECAST...AND IN FACT IF THE 30.00Z ECMWF IS CORRECT...MONDAY COULD BE A VERY WARM AND EVEN HUMID DAY ACROSS MUCH OF THE FORECAST AREA. SUGGESTION FROM THE MODEL IS HIGHS IN THE LOW 80S AND DEWPOINTS IN THE LOW 60S...ALL FROM THE LOW PRESSURE SYSTEM IN THE CENTRAL PLAINS LIFTING NORTHEAST INTO NORTHWEST WISCONSIN. HAVE NOT JUMPED ON THIS SCENARIO QUITE YET...SINCE MOST MODELS KEEP THIS SYSTEM TO THE SOUTH OF THE AREA...BUT DEFINITELY WARRANTS WATCHING. ALSO THE ECMWF WOULD SUGGEST SOME STRONG CONVECTION AT LEAST AS THE COLD FRONT COMES THROUGH. NEEDLESS TO SAY...CHANCES OF PRECIPITATION CONTINUE IN THE FORECAST FOR MONDAY INTO MONDAY NIGHT...MAINLY IN THE 20-40 RANGE UNTIL THIS WHOLE SYSTEM CAN BE IRONED OUT. DRYING TREND THEN IS FORECAST FOR TUESDAY AND CONTINUING THROUGH THE REST OF THE LONG TERM PERIOD WITH MOST MODELS AND ENSEMBLES SHOWING NORTHWEST FLOW OVER THE FORECAST AREA. DID KEEP A 20 PERCENT CHANCE OF SHOWERS GOING ON TUESDAY WITH THE UPPER TROUGH MOVING THROUGH...THOUGH. HOW MUCH NORTHWEST FLOW AND THE COLD AIR ASSOCIATED WITH IT VARIES...SO FOR NOW STAYED WITH A BLEND OF MODELS FOR TEMPERATURES. READINGS STILL LOOK TO STAY ABOVE NORMAL AS HIGHS ONLY DROP INTO THE MID TO UPPER 50S AT THE LOWEST. NORMAL HIGHS ARE IN THE LOW 50S. && .AVIATION...THROUGH 06Z SATURDAY 1201 AM CDT THU MAR 29 2012 A MID LEVEL SHORTWAVE TROUGH WAS MOVING INTO WESTERN MINNESOTA LATE THIS EVENING. THE ATTENDANT SURFACE LOW WAS LOCATED OVER NORTHEAST KANSAS/SOUTHEAST NEBRASKA. MOISTURE TRANSPORT AHEAD OF THE LOW WAS SPAWNING SHOWERS AND THUNDERSTORMS FROM IOWA INTO MINNESOTA. THE STRONGEST STORMS WERE LOCATED OVER SOUTHERN IOWA. THUS FAR CEILINGS HAVE REMAINED IN THE VFR CATEGORY AT THE TAF SITES. HOWEVER...AS LOW LEVEL MOISTURE CONTINUES TO INCREASE...SHOWERS WILL BECOME MORE NUMEROUS AND BUFKIT SOUNDINGS FROM BOTH THE 30.02 RUC AND 30.00Z NAM SHOWS LOW LEVEL SATURATION TAKING PLACE THROUGH THE NIGHT. THUS EXPECT CEILINGS TO FALL INTO THE MVFR CATEGORY...AND EVEN INTO THE IFR CATEGORY AT KRST. THE SHOWERS WILL END AROUND 14-15Z FRIDAY...BUT ALTHOUGH CEILINGS WILL SLOWLY RISE...MODELS SUGGEST THEY WILL STAY IN THE MVFR CATEGORY FOR MUCH OF THE DAY...RISING INTO THE VFR CATEGORY LATE IN THE DAY. STILL UNCERTAINTY WITH CLEARING TREND FRIDAY EVENING BETWEEN 00Z-06Z. NAM CONTINUES TO SHOW QUITE BIT OF LOW LEVEL MOISTURE. DID SCATTERED THE CLOUDS OUT AT KRST...BUT KEPT A BROKEN VFR CEILINGS AT KLSE THROUGH 06Z. && .HYDROLOGY... 329 AM CDT FRI MAR 30 2012 AS OF 3 AM...MAJORITY OF THE PRECIPITATION SO FAR HAS FALLEN ALONG AND SOUTH OF A LINE FROM ST ANSGAR IOWA TO WINONA MN AND BLACK RIVER FALLS WISCONSIN. RADAR ESTIMATES SHOW THAT THE SHOWERS AND THUNDERSTORMS PRODUCED AMOUNTS RANGING FROM 0.25 TO 0.75 INCHES. HOWEVER...THERE IS AN AREA COVERING SOUTHEAST FAYETTE...MUCH OF CLAYTON AND NORTHERN GRANT COUNTIES WHERE 0.75 TO 1.75 INCHES FELL...HIGHEST NEAR STRAWBERRY POINT. NO REPORTS OF ANY FLOODING THUS FAR BUT EXPECT SOME BRIEF RISES IN SMALL STREAMS. WILL HAVE TO KEEP AN EYE ON THE TURKEY RIVER...THOUGH THE LACK OF SIGNIFICANT RAINFALL AND GENERALLY DRY SOILS SHOULD KEEP THE RIVER BELOW FLOOD STAGE. && .ARX WATCHES/WARNINGS/ADVISORIES... 328 AM CDT FRI MAR 30 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...RABERDING HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1201 AM CDT FRI MAR 30 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT 346 PM CDT THU MAR 29 2012 AT 3 PM...A SHORT WAVE TROUGH WAS PRODUCING A CLUSTER OF THUNDERSTORMS ACROSS SOUTHERN IOWA AND NORTHERN MISSOURI. FURTHER TO THE WEST OVER THE CENTRAL AND NORTHERN PLAINS... THERE WERE TWO ADDITIONAL SHORT WAVE TROUGHS. THE 29.12Z MODELS ARE IN FAIRLY GOOD AGREEMENT THE SHORT WAVE OVER THE NORTHERN PLAINS WILL MOVE ACROSS NORTHERN MINNESOTA AND WESTERN ONTARIO TONIGHT. MEANWHILE THE SECOND SHORT WAVE /CURRENTLY OVER THE CENTRAL PLAINS WILL EAST SOUTHEAST ACROSS IOWA AND MISSOURI TONIGHT AND FRIDAY. AS A RESULT... THE BEST FORCING WILL BE TO THE NORTH AND SOUTH OF THE FORECAST AREA TONIGHT. EVEN THOUGH THIS WILL BE THE CASE... THE 850 MB JET WILL FOCUS MODEST MOISTURE TRANSPORT INTO THE AREA FOR LATE THIS EVENING AND OVERNIGHT. AS A RESULT...THE AREA WILL SEE ANYWHERE FROM A QUARTER TO A HALF INCH OF RAIN AS THESE SYSTEMS MOVE THROUGH THE REGION. IN AREAS WHERE THE FORCING IS BETTER PRECIPITATION TOTALS WILL LIKELY RANGE FROM A HALF TO ONE INCH. THE MODELS CONTINUE TO INDICATE THAT THERE WILL BE SOME ELEVATED CAPES /UP TO 200 J/KG MOVING ACROSS THE AREA FROM LATE THIS EVENING INTO THE OVERNIGHT. THIS SHOULD BE ENOUGH TO KEEP THE ISOLATED THUNDERSTORMS IN THE FORECAST. IN ADDITION...THE MODEL SOUNDINGS ACROSS TAYLOR AND NORTHERN CLARK COUNTIES SHOW THAT THERE WILL BE AN ELEVATED WARM LAYER /UP 2C/ BETWEEN 900 MB AND 750 MB WITH A COLD LAYER BELOW. THIS WILL BE DEEP ENOUGH TO REFREEZE ANY SNOW THAT MELTED IN THE WARM LAYER AFTER MIDNIGHT. AS A RESULT...WENT WITH A MIX OF RAIN...SLEET...AND SNOW FOR THESE COUNTIES. WITH THE SURFACE TEMPERATURES AND SOILS UNUSUALLY WARM...NOT EXPECTING ANY ACCUMULATIONS OF SNOW OR SLEET FROM THIS SYSTEM. ON FRIDAY...THE MODELS ARE INDICATING THAT THERE WILL BE A CHANCE OF LIGHT RAIN OR DRIZZLE ACROSS WISCONSIN DURING THE MORNING. ADDITIONAL RAINFALL AMOUNTS WILL LIKELY ONLY RANGE FROM A TRACE TO A FEW HUNDREDTHS OF AN INCH. LIKE THE PAST COUPLE OF DAYS...THE MODELS CONTINUE TO SHOW THAT EAST WINDS OFF OF THE GREAT LAKES WILL BRING MUCH COOLER TEMPERATURES INTO THE REGION. TEMPERATURES ACROSS MUCH OF EASTERN WISCONSIN WILL LIKELY ONLY GET INTO THE 40S. MEANWHILE TEMPERATURES IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA WILL BE MAINLY IN THE 60S. ON FRIDAY NIGHT...IT CONTINUES TO LOOK LIKE A SURFACE HIGH WILL BUILD ACROSS NORTHERN AND EASTERN WISCONSIN. THIS HIGH WILL RESULT IN LIGHT AND VARIABLE WINDS AND ALLOW THE TEMPERATURES TO FALL OFF INTO THE MID 30S ACROSS NORTH-CENTRAL AND CENTRAL WISCONSIN. IF SKIES HAPPEN TO CLEAR OFF MORE THAN EXPECTED...THESE TEMPERATURES MAY FALL TO AROUND 30. FOR THE TIME BEING...JUST MENTIONED THE POSSIBILITY OF FROST IN THE GRIDS TO COVER THIS POTENTIAL. ON SATURDAY AFTERNOON AND NIGHT...A WARM FRONT WILL BE LOCATED ACROSS NORTHERN IOWA AND NORTHERN ILLINOIS. THE MODELS THAT THE 850 MB JET WILL BRING SOME MODEST MOISTURE TRANSPORT INTO NORTHEAST IOWA AND SOUTHWEST WISCONSIN. THE NAM/WRF IS THE MOST ROBUST AND THE FASTEST AT GENERATING PRECIPITATION ACROSS THIS AREA. MEANWHILE THE OTHER MODELS SUGGEST THAT THE BETTER CHANCES WILL BE ON SATURDAY EVENING. WITH MEAN LAYER CAPES CLIMBING INTO THE 500 TO 1000 J/KG RANGE...THERE WILL BE THE POTENTIAL OF SOME THUNDERSTORMS. THE MODELS SHOW 0-6KM SHEAR IN THE EXCESS OF 40 KNOTS. HOWEVER WITH MUCH OF THE SHEAR LOCATED BELOW THE INVERSION...THERE IS SOME CONCERN THAT THE MODELS MAY BE OVERDOING THE SHEAR AVAILABLE FOR THESE THUNDERSTORMS. THIS AREA IS CURRENTLY UNDER SEE TEXT FOR DAY 3 AND WILL HAVE TO BE WATCHED OVER THE NEXT TWO DAYS. IF SEVERE WEATHER DID HAPPEN TO OCCUR... THE MAIN SEVERE WEATHER THREAT WOULD BE LARGE HAIL. .LONG TERM...SUNDAY THROUGH THURSDAY 346 PM CDT THU MAR 29 2012 FOR SUNDAY...THE MODELS CONTINUE TO STRUGGLE WITH THE LOCATION OF THE WARM FRONT. SOME OF THE MODELS SUGGEST A FURTHER SOUTHWEST LOCATION. AS A RESULT...WESTERN WISCONSIN IS NOT AS WARM AS SOME MODELS INDICATE...THEREFORE...WENT MORE CONSERVATIVE WITH MAXIMUM TEMPERATURES FOR THIS TIME PERIOD. FOR THE REMAINDER OF THIS TIME PERIOD...THE MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND STRENGTH OF SHORT WAVES MOVING THROUGH THE REGION. THIS MAKES THE TEMPERATURE AND PRECIPITATION FORECAST RATHER UNCERTAIN. AS A RESULT...STAYED WITH THE ALL BLEND DATA. && .AVIATION...THROUGH 06Z SATURDAY 1201 AM CDT THU MAR 29 2012 A MID LEVEL SHORTWAVE TROUGH WAS MOVING INTO WESTERN MINNESOTA LATE THIS EVENING. THE ATTENDANT SURFACE LOW WAS LOCATED OVER NORTHEAST KANSAS/SOUTHEAST NEBRASKA. MOISTURE TRANSPORT AHEAD OF THE LOW WAS SPAWNING SHOWERS AND THUNDERSTORMS FROM IOWA INTO MINNESOTA. THE STRONGEST STORMS WERE LOCATED OVER SOUTHERN IOWA. THUS FAR CEILINGS HAVE REMAINED IN THE VFR CATEGORY AT THE TAF SITES. HOWEVER...AS LOW LEVEL MOISTURE CONTINUES TO INCREASE...SHOWERS WILL BECOME MORE NUMEROUS AND BUFKIT SOUNDINGS FROM BOTH THE 30.02 RUC AND 30.00Z NAM SHOWS LOW LEVEL SATURATION TAKING PLACE THROUGH THE NIGHT. THUS EXPECT CEILINGS TO FALL INTO THE MVFR CATEGORY...AND EVEN INTO THE IFR CATEGORY AT KRST. THE SHOWERS WILL END AROUND 14-15Z FRIDAY...BUT ALTHOUGH CEILINGS WILL SLOWLY RISE...MODELS SUGGEST THEY WILL STAY IN THE MVFR CATEGORY FOR MUCH OF THE DAY...RISING INTO THE VFR CATEGORY LATE IN THE DAY. STILL UNCERTAINTY WITH CLEARING TREND FRIDAY EVENING BETWEEN 00Z-06Z. NAM CONTINUES TO SHOW QUITE BIT OF LOW LEVEL MOISTURE. DID SCATTERED THE CLOUDS OUT AT KRST...BUT KEPT A BROKEN VFR CEILINGS AT KLSE THROUGH 06Z. && .ARX WATCHES/WARNINGS/ADVISORIES... 346 PM CDT THU MAR 29 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
406 AM CDT SUN APR 1 2012 .DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * SCATTERED BANDS OF TSRA APPROACHING FROM THE WEST AROUND 10Z. INTERMITTENT TSRA EXPECTED UNTIL AROUND 12Z...POSSIBLY LINGERING TIL 13-14Z IF NEW DEVELOPMENT ON THE REAR FLANK. * WIND SHIFT TO NORTHEAST BY LATE MORNING/MID-DAY. WINDS MAY BECOME LIGHT AND VARIABLE FOR A FEW HOURS AS THIS OCCURS. * POTENTIAL FOR PERIOD OF MVFR CEILINGS 1500-2000 FT LATE MORNING TO MID-AFTERNOON. MDB //DISCUSSION...UPDATED 09Z... BAND OF CLUSTERED SHRA/TSRA CONTINUES TO MOVE EASTWARD INTO THE FAR WESTERN CHI METRO AREA AT 09Z. THIS WILL CONTINUE TO MOVE EASTWARD OVER THE NEXT SEVERAL HOURS BRINGING BRIEF HEAVY DOWNPOURS AND IFR/MVFR VSBY. SOME ADDITIONAL DEVELOPMENT MAY OCCUR IMMEDIATELY BEHIND THE CURRENT BAND PROLONGING THE DURATION SOMEWHAT. MDB FROM 06Z... INITIAL CONCERN THIS MORNING IS WITH POTENTIAL FOR THUNDERSTORMS TO AFFECT TERMINALS DURING THE PRE-DAWN HOURS. AREA OF ELEVATED CONVECTION OVER FAR WESTERN IL AND NORTHEAST IA IS SLOWLY PROPAGATING TO THE EAST-SOUTHEAST AND WOULD LIKELY SKIRT SOUTH OF TERMINALS LATER THIS AM. NEW DEVELOPMENT CONTINUES TO OCCUR ON THE NORTHERN FRINGE OF THE CONVECTIVE COMPLEX ACROSS NORTHEAST IA HOWEVER...AND SEVERAL HIGH RES EXPLICIT CONVECTION MODELS CONTINUE TO DEPICT CONTINUED DEVELOPMENT INTO FAR NORTHERN IL TOWARD 09-10Z. THEREFORE HAVE MAINTAINED A BRIEF TEMPO MENTION FOR TS WITH SOME MINOR TIMING ADJUSTMENTS BASED ON RADAR EXTRAPOLATION PARTICULARLY FOR KRFD. ONCE MORNING STORMS MOVE OFF TO THE EAST...NEXT CONCERN IS WINDS SHIFTING TO THE NORTHEAST AND THE POTENTIAL FOR A PERIOD OF MVFR CEILINGS. GUIDANCE CONTINUES TO INDICATE WIND SHIFT BY VERY LATE MORNING/MID-DAY AS WEAK SURFACE WAVE MOVES EAST AND REINFORCING COLD FRONT SAGS SOUTH ACROSS TERMINALS. FORECAST SOUNDINGS DEPICT MOIST LAYER 1500-2000 FT IN COOL ADVECTION BENEATH INVERSION ALOFT. FORECAST SOUNDINGS INDICATE ENOUGH DRYING TAKES PLACE BY MID-LATE AFTERNOON TO SCATTER CLOUDS. WINDS...SOUTHEAST LESS THAN 10 KTS AT TAF ISSUANCE EXPECTED TO BECOME SOUTH OVERNIGHT...THEN LIGHT WESTERLY AFTER SUNRISE. AFOREMENTIONED FRONT THEN SAGS THROUGH WITH SHIFT TO THE NORTHEAST BY LATE MORNING OR SO...WITH GUSTS TO 15 KT POSSIBLE IN DEEPER MIXING WITH LOW LEVEL COLD ADVECTION. RATZER //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN TSRA AFFECTING THE IMMEDIATE TERMINAL AREAS APPROX 10-12Z...WITH LOW CONFIDENCE IN POTENTIAL FOR NEW DEVELOPMENT IMMEDIATELY BEHIND CURRENT ACTIVITY PROLONGING IMPACT. * HIGH CONFIDENCE IN WIND TRENDS THROUGH PERIOD. * MEDIUM CONFIDENCE IN PERIOD OF 1500-2000 FT CIGS LATE MORNING INTO THIS AFTERNOON. MDB //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR WITH CHANCE TSRA MONDAY NIGHT. TUESDAY...VFR WITH CHANCE SHRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. RATZER && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
320 AM CDT SUN APR 1 2012 .DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * COVERAGE/TIMING OF THUNDERSTORMS EARLY THIS MORNING. * WIND SHIFT TO NORTHEAST BY LATE MORNING/MID-DAY. * POTENTIAL FOR PERIOD OF MVFR CEILINGS 1500-2000 FT LATE MORNING TO MID-AFTERNOON. RATZER //DISCUSSION...UPDATED 06Z... INITIAL CONCERN THIS MORNING IS WITH POTENTIAL FOR THUNDERSTORMS TO AFFECT TERMINALS DURING THE PRE-DAWN HOURS. AREA OF ELEVATED CONVECTION OVER FAR WESTERN IL AND NORTHEAST IA IS SLOWLY PROPAGATING TO THE EAST-SOUTHEAST AND WOULD LIKELY SKIRT SOUTH OF TERMINALS LATER THIS AM. NEW DEVELOPMENT CONTINUES TO OCCUR ON THE NORTHERN FRINGE OF THE CONVECTIVE COMPLEX ACROSS NORTHEAST IA HOWEVER...AND SEVERAL HIGH RES EXPLICIT CONVECTION MODELS CONTINUE TO DEPICT CONTINUED DEVELOPMENT INTO FAR NORTHERN IL TOWARD 09-10Z. THEREFORE HAVE MAINTAINED A BRIEF TEMPO MENTION FOR TS WITH SOME MINOR TIMING ADJUSTMENTS BASED ON RADAR EXTRAPOLATION PARTICULARLY FOR KRFD. ONCE MORNING STORMS MOVE OFF TO THE EAST...NEXT CONCERN IS WINDS SHIFTING TO THE NORTHEAST AND THE POTENTIAL FOR A PERIOD OF MVFR CEILINGS. GUIDANCE CONTINUES TO INDICATE WIND SHIFT BY VERY LATE MORNING/MID-DAY AS WEAK SURFACE WAVE MOVES EAST AND REINFORCING COLD FRONT SAGS SOUTH ACROSS TERMINALS. FORECAST SOUNDINGS DEPICT MOIST LAYER 1500-2000 FT IN COOL ADVECTION BENEATH INVERSION ALOFT. FORECAST SOUNDINGS INDICATE ENOUGH DRYING TAKES PLACE BY MID-LATE AFTERNOON TO SCATTER CLOUDS. WINDS...SOUTHEAST LESS THAN 10 KTS AT TAF ISSUANCE EXPECTED TO BECOME SOUTH OVERNIGHT...THEN LIGHT WESTERLY AFTER SUNRISE. AFOREMENTIONED FRONT THEN SAGS THROUGH WITH SHIFT TO THE NORTHEAST BY LATE MORNING OR SO...WITH GUSTS TO 15 KT POSSIBLE IN DEEPER MIXING WITH LOW LEVEL COLD ADVECTION. RATZER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE THUNDERSTORMS WILL AFFECT TRACON AIRSPACE...BUT MEDIUM CONFIDENCE IN DIRECT IMPACT ON INDIVIDUAL TERMINALS. * HIGH CONFIDENCE IN WIND TRENDS THROUGH PERIOD. * MEDIUM CONFIDENCE IN PERIOD OF 1500-2000 FT CIGS LATE MORNING INTO THIS AFTERNOON. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR WITH CHANCE TSRA MONDAY NIGHT. TUESDAY...VFR WITH CHANCE SHRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. RATZER && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
302 AM CDT SUN APR 1 2012 .DISCUSSION... ISSUED 300 AM CDT SUN APR 1 2012 SMALL MCS FORMED AS EXPECTED OVER EASTERN IOWA LATE IN THE EVENING...AND HAS BEEN MOVING ACROSS THE NORTHERN CWA OVERNIGHT...PRODUCING SEVERE HAIL AT TIMES. HAVE SEEN SOME SHOWERS/STORMS AS FAR SOUTH AS LINCOLN AT 2 AM. SHORT TERM...TODAY THROUGH TUESDAY... LATEST HRRR MODEL...WHICH HAS A GOOD HANDLE ON THE ACTIVITY... SHOWS MUCH OF THE RAIN SHOULD LARGELY BE OUT OF THE CWA BY SUNRISE. WILL MAKE A LAST MINUTE DECISION ON HOW LONG TO LINGER IT THIS MORNING. ONCE THAT CLEARS OUT...TEMPERATURES BECOME THE PRIMARY FOCUS. STILL LOOKING FOR HIGHS IN THE 80S ACROSS THE ENTIRE AREA...CLOSE TO THE DAILY RECORDS. HOWEVER...EVENING MODEL RUNS SHOWING A FRONTAL BOUNDARY NEAR THE I-80 CORRIDOR WILL LIKELY SLIP A BIT SOUTHWARD THIS AFTERNOON...DRIVEN BY A RATHER STIFF NORTHEAST FLOW. IF IT SLIPS TOO FAR...THEN TEMPERATURES ACROSS THE NORTHEAST CWA MAY END UP BEING COOLER THAN EXPECTED. WRF MODEL OUT OF WFO CHICAGO HAS THE BOUNDARY ALMOST ALL THE WAY TO I-74 BY 6 PM. WILL NEED TO WATCH THIS CLOSELY DURING THE AFTERNOON. BOUNDARY WILL PROBABLY REACH AT LEAST INTO PART OF THE CWA THIS EVENING...BEFORE BEGINNING TO RETREAT. SAME PROBLEM EXISTS WITH TEMPERATURES MONDAY AFTERNOON...DUE TO ITS POSITION. HAVE PULLED HIGH TEMPERATURES DOWN A BIT NORTH OF I-74...BUT STILL GOING A FEW DEGREES ABOVE GUIDANCE IN THAT AREA. REMAINDER OF THE CWA MORE LIKELY TO REACH THE 85-90 DEGREE RANGE...AGAIN NEAR THE RECORDS. TIMING OF COLD FRONTAL PASSAGE TUESDAY MORNING APPEARS TO HAVE SLOWED A BIT FROM EARLIER RUNS...SO HAVE KEPT TEMPERATURES SOUTH OF I-70 WARMER THAN PREVIOUSLY FORECAST...WITH LOWER 80S. THREAT OF SHOWERS/STORMS TO CONTINUE INTO THE AFTERNOON WITH THE BOUNDARY IN THE AREA. LONG TERM...WEDNESDAY THROUGH SATURDAY... STILL LOOKING TO BE MUCH COOLER THAN THE START OF THE WEEK...ALTHOUGH STILL A BIT ABOVE NORMAL. FOCUS IN THIS PERIOD REMAINS WITH A CUTOFF LOW WHICH WILL DEVELOP OVER THE SOUTHERN ROCKIES EARLY IN THE WEEK. LONGER RANGE MODELS IN REASONABLE AGREEMENT WITH A TRACK THAT TAKES IT SOUTH OF THE OHIO VALLEY...BUT WILL STILL SEE THE RAIN SHIELD ON THE NORTHERN FLANK EXTEND WELL TO THE NORTH. HAVE CUT BACK ON THE RAIN ACROSS THE NORTHERN CWA FOR WEDNESDAY/THURSDAY... WITH THE PERSISTENT NORTHEAST FLOW BRINGING DRIER AIR INTO CENTRAL ILLINOIS. MAINLY DRY CONDITIONS EXPECTED LATE IN THE WEEK...AS A NARROW RIDGE OF HIGH PRESSURE MOVES INTO THE MISSISSIPPI VALLEY. GEELHART && .AVIATION... ISSUED 1240 AM CDT SUN APR 1 2012...FOR THE 06Z TAFS STORMS WILL PUSH ACROSS PIA/BMI/CMI BETWEEN 06Z AND 09Z...WITH MVFR VIS IN HEAVY RAIN AND SMALL HAIL. BASED ON UPSTREAM OBS DURING STORMS...CIGS SHOULD REMAIN VFR DURING THE STORMS. WIND GUSTS UP TO 35 MPH ARE POSSIBLE. LIGHTER RAIN AND MORE ISOLATED THUNDERSTORMS ARE PROJECTED TO REACH THE SOUTHERN TERMINALS OF SPI/DEC. STILL BRIEF PERIODS OF MVFR VIS IN RAIN IS POSSIBLE. WE DID NOT INCLUDE TEMPOS FOR MVFR AT SPI/DEC WITH THE INITIAL ISSUANCE...AS WE EXPECT THE LINE OF STORMS TO WEAKEN AS IT PROGRESSES FARTHER FROM THE FAVORABLE WIND SHEAR...LLJ...AND INSTABILITY. SKIES ARE EXPECTED TO CLEAR RELATIVELY QUICKLY BEHIND THE LINE OF SHOWERS/STORMS. A PERIOD OF MVFR VIS IN FOG MAY DEVELOP IN PIA/BMI/CMI IF ANY CLEARING DEVELOPS BEFORE SUNRISE. FOG WOULD CLEAR TO VFR BY 15Z IN THAT SCENARIO. WINDS WILL VEER FROM SOUTHEAST TO SOUTHWEST BETWEEN 10Z-14Z...THEN REMAIN SOUTHWEST UNTIL A BACK DOOR COLD FRONT REACHES NEAR PIA/BMI/CMI TOWARD 06Z. THEN WINDS WILL BACK TO THE EAST BEHIND THAT FRONT. SHIMON && .CLIMATE... ISSUED 218 AM CDT SUN APR 1 2012 RECORD HIGHS FOR TODAY...MONDAY... BLOOMINGTON......82/1981...85/1903 CHAMPAIGN........83/1946...81/1932 DECATUR..........87/1946...85/1940 EFFINGHAM........83/1986...82/2010 JACKSONVILLE.....85/1946...85/1903 LINCOLN..........85/1946...84/1940 OLNEY............85/1946...85/1940 PEORIA...........83/1946...84/1940 SPRINGFIELD......87/1946...87/1981 GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
214 AM CDT SUN APR 1 2012 .DISCUSSION... 908 PM CDT SOME MINOR CHANGES TO POPS AND WX FOR TONIGHT. MAINLY DELAYING ARRIVAL OF THREAT OF SHRA AND TSRA UNTIL LATER TONIGHT AND REDUCING POPS OVER FAR NE IL FOR OVERNIGHT. RADAR COMPOSITE SHOWS WEAK ECHOES TO THE W THRU N OF THE LOCAL AREA WHERE INITIAL WAA AND RESULTING UVV AT MAINLY MID LEVELS OCCURRING. EXPECT THESE ECHOES...ALREADY MOSTLY VIRGA UPSTREAM WITH FEW IF ANY METARS REPORTING ANY PRECIP...WILL CONTINUE TO DRY UP AS THEY MOVE INTO INCREASINGLY DRY MID AND LOW LEVELS. A THUNDERSTORM DEVELOPED JUST NE OF DSM AROUND 0030Z AND ARE SLOWLY INCREASING IN NUMBER AS THEY MOVE ENE-E. THESE TSRA ARE WHERE BETTER MOISTURE IN THE 850 TO 800 HPA LAYER IS IN PLACE...WHERE WEAK SURFACE CONVERGENCE IS OCCURRING...WHERE NOSE OF 45 KT SOUTHWESTERLY JET AT 5 TO 6 K FT AGL SHOWN BY KDMX VAD WIND PROFILE IS LOCATED...AND JUST AHEAD OF WEAK MID LEVEL SHORT WAVE TROF MOVING OVER CENTRAL IA. CHALLENGE TO FORECAST IS HOW EXTENSIVE FURTHER TSRA DEVELOPMENT WILL BE AND WHERE AREA OF STORMS IS LIKELY TO MOVE OVERNIGHT. LATEST RUC13 RUN INDICATES A RATHER SMALL AREA OF MID LEVEL ISENTROPIC LIFT CURRENTLY OVER CENTRAL IA MOVES THIS AREA EASTWARD TO E CENTRAL IA 04-06Z...AND THEN SOUTHEASTWARD ACROSS N CENTRAL IL TO THE CENTRAL IL-IND BORDER BY 12Z. THIS APPEARS TO BE BEST TRACK FOR THE ELEVATED TSRA THAT IS EXPECTED TO BE MAINTAINED THROUGH THE OVERNIGHT BY THE LLJ...THE MID LEVEL SHORT WAVE AND STEEPENING MID LEVEL LAPSE RATES. EXPECT RATHER SMALL AREA OF TSRA AS MOISTURE WILL BE MARGINAL SO ONLY ANTICIPATE ACTIVITY WHERE FORCING FACTORS ARE MAXIMIZED DURING THE OVERNIGHT. TRS //PREV DISCUSSION... 317 PM CDT MAIN FORECAST ISSUES/CONCERNS FOR THE REMAINDER OF THE WEEKEND ARE WITH CHANCES FOR SHOWERS/THUNDERSTORMS LATE TONIGHT INTO SUNDAY MORNING...AS WELL AS TEMPERATURE TRENDS SUNDAY. WITH THE LOW LEVEL CLOUD COVER TODAY MASKING THE FACT THAT HIGH PRESSURE IS OVERHEAD...RELATIVELY QUIET CONDITIONS HAVE BEEN IN PLACE FOR ALL OF TODAY. ALTHOUGH...OVER THE LAST COUPLE OF HOURS SEVERAL HOLES DEVELOPED WITHIN THIS LOW LEVEL MOISTURE. A WARM SUN AND DRIER AIR ALOFT HAS ALLOWED FOR THESE HOLES TO CONTINUE TO EXPAND WITH SOME AREAS ACROSS THE SOUTHERN CWA OBSERVING SUNNY TO PARTLY CLOUDY SKIES. WITHIN THESE AREAS OF BETTER SOLAR INSOLATION...TEMPS HAVE QUICKLY RISEN INTO THE 50S WITH SOME AREAS OBSERVING SOME PLEASANT CONDITIONS AS RATHER LIGHT FLOW REMAINS IN PLACE. EXPECT THIS LOW CLOUD SHIELD TO CONTINUE TO ERODE WITH TIME LATE THIS AFTERNOON AND EARLY EVENING BUT WITH SOME MID AND HIGH LEVEL CLOUD COVER TO PUSH OVERHEAD. THIS IN ITSELF SHOULD PROVIDE PARTLY CLOUDY SKIES FOR TONIGHT...BUT WITH PRECIP CHANCES LATER TONIGHT TO POSSIBLY BRING MORE CLOUDY CONDITIONS MORE TOWARDS EARLY SUNDAY MORNING. LATEST GUIDANCE CONTINUES TO INDICATE SHOWERS AND THUNDERSTORMS DEVELOPING TONIGHT ACROSS EASTERN IOWA AND SHIFTING EAST/SOUTHEAST ACROSS A PORTION OF THE CWA THROUGH SUNDAY MORNING. ALL GUIDANCE IS INDICATING THIS POSSIBILITY BUT WITH SOME VARIABILITY STILL REMAINING WITH REGARDS TO EXACT TIMING AND PLACEMENT/TRACK. WITH BACKING 850MB FLOW...A WARMER AND MORE MOIST AIR MASS LOCATED ACROSS THE CENTRAL PLAINS WILL ADVECT NORTH/NORTHEAST WITH TIME TONIGHT BRINGING HIGHER DEW POINT AIR TO THE REGION. NORTHWEST FLOW ALOFT WILL STEER A MID LEVEL IMPULSE AND ATTENDANT SURFACE TROUGH OUT OF THE NORTHERN PLAINS THIS EVENING...AND HELP TO INITIATE CONVECTION ALONG A LOW LEVEL BAROCLINIC ZONE DRAPED ACROSS THE REGION. WITH LOW LEVEL FLOW FEEDING HIGHER THETA E AIR OVER THIS BOUNDARY AND INTO ANY DEVELOPING PRECIP...THIS AREA OF CONVECTION COULD SEE SOME EXPANSION IN COVERAGE AS IT SHIFTS EAST/SOUTHEAST THROUGH THE CWA EARLY SUNDAY MORNING. ALTHOUGH...GUIDANCE CONTINUES TO STRUGGLE WITH EXACT TIMING OF WHEN CONVECTION WILL DEVELOP AND WHERE THIS DEVELOPING AREA OF PRECIPITATION WILL PROGRESS THROUGH. DUE TO THIS UNCERTAINTY STILL IN PLACE...HAVE NOT MADE MANY CHANGES TO THE GOING POP GRIDS FOR TONIGHT KEEPING HIGH CHANCE POPS FOR MUCH OF THE CWA AFTER THE MIDNIGHT TIME FRAME THROUGH MID MORNING SUNDAY. THIS IS BASED ON THE LIKELIHOOD THAT CONVECTION SHOULD BEGIN TO DEVELOP OVER IOWA ONCE WE DECOUPLE AND THE LLJ RAMPS UP...WHICH SHOULD BE AROUND THE 3Z-6Z TIME FRAME. SOME HI RES DATA IS SHOWING THE POSSIBILITY OF AN MCS DEVELOPING AND QUICKLY SHIFTING THROUGH THE REGION SUNDAY MORNING. HAVE NOT COMPLETELY THROWN THIS OUT AS A POSSIBILITY...WITH DECENT LOW LEVEL SHEAR TO BE PRESENT ACROSS THE REGION. A LIMITING FACTOR WILL BE THE AMOUNT OF INSTABILITY PRESENT OVER NORTHERN ILLINOIS AND NORTHWEST...WHICH AM CURRENTLY LEANING MORE ON THE SREF MUCAPE OUTPUT WHICH IS SHOWING WEAKER INSTABILITY PRESENT BY EARLY SUNDAY MORNING LIMITING MORE ROBUST CONVECTION...WITH OTHER GUIDANCE OF COURSE ALSO VARYING TO THIS AMOUNT. SO WITH ANY PRECIP WHICH MOVES THROUGH THE AREA LATE TONIGHT AND EARLY SUNDAY MORNING...A MORE LIKELY SCENARIO WILL BE FOR THIS TO BE AN UNORGANIZED AREA OF SHOWERS AND ELEVATED THUNDERSTORMS WITH LITTLE CHANCES FOR SEVERE WEATHER...HAIL/WIND. ONLY AN ISOLATED THREAT OF HAIL COULD BE OBSERVED MAINLY FOR THE WESTERN CWA WHERE BETTER INSTABILITY AND STRONGER EFFECTIVE BULK SHEAR WILL RESIDE. EVEN IF A MORE ORGANIZED MCS COULD DEVELOP...WOULD EXPECT IT TO FOLLOW THE HIGHER SURFACE DEW POINT AIR AND BETTER INSTABILITY WHICH WOULD MORE THAN LIKELY BE SITUATED TO THE SOUTH OF THE CWA. THUS...ONCE AGAIN KEEPING ANY THREAT FOR SEVERE WEATHER JUST OUTSIDE OF THE CWA. THIS SITUATION WARRANTS CONTINUED MONITORING...AND WILL MAINTAIN A MENTION FOR THE CHANCES FOR THUNDERSTORMS TONIGHT IN THE HWO. ANY LINGERING SHOWERS/THUNDERSTORMS SHOULD EXIT THE CWA BY MID DAY WITH PARTLY CLOUDY TO SUNNY CONDITIONS EXPECTED THROUGH THE AFTERNOON. THE EXTENT OF THE MORNINGS PRECIP WILL DEFINITELY PLAY A KEY ROLE WITH MAX TEMPS ON SUNDAY WITH PERSISTENT WAA ADVECTING A WARMER AIR MASS OVERHEAD. AS SURFACE WARM FRONT TRIES TO LIFT NORTHEAST ACROSS THE CWA DURING THE DAY SUNDAY...IT WILL ACTUALLY BEGIN TO RETREAT AS A COLD FRONT WITH COOLER LOW LEVEL AIR WORKING ITS WAY BACK WEST ACROSS THE CWA LATE IN THE AFTERNOON AND EARLY EVENING. SO OUTSIDE OF PRECIP TRENDS POSSIBLY AFFECTING TEMP TRENDS SUNDAY...PLACEMENT OF THIS BOUNDARY AND MOVEMENT WILL BE KEY IN DEFINING MAX TEMPS FOR SUNDAY. DID BRING DOWN TEMPS A TAD FROM GOING FORECAST BUT HAVE KEPT THE WEST/SOUTHWEST CWA WARMER THAN THE EAST WITH AREAS STILL TO POSSIBLY REACH THE 80 MARK...AND AREAS ACROSS THE EASTERN CWA TO REACH THE LOWER 70S WITH 60S EXPECTED FOR AREAS NEAR THE LAKE. HAVE ADDED SLIGHT CHANCE POPS FOR THE SOUTHEAST PORTION OF THE CWA FOR SUNDAY AFTERNOON WHERE BETTER FOCUS AND UPPER LEVEL SUPPORT COULD PROVIDE FOR DEVELOPMENT OF THUNDERSTORMS. STRONG UPPER LEVEL RIDGING WILL OCCUR ON MONDAY WITH MID AND UPPER LEVEL FLOW BECOMING RATHER WEAK. THIS WEAK FLOW COINCIDING WITH A FORECASTED CLOSED UPPER LEVEL LOW TRACKING THROUGH THE SOUTHERN US WILL PROVIDE A TRICKY FORECAST THROUGH THE REMAINDER OF THE WEEK WITH THE ANTICIPATION FOR GUIDANCE TO CONTINUE TO STRUGGLE WITH PLACEMENT OF LOW LEVEL FEATURES AND INEVITABLE PRECIP. ALTHOUGH...THERE DOES APPEAR TO BE BETTER CHANCES FOR OBSERVING CONVECTION MONDAY NIGHT. BETTER FORCING AS WELL AS INSTABILITY LOOK TO BE IN PLACE FOR THE DEVELOPMENT OF POSSIBLY MORE ORGANIZED CONVECTION...WITH CURRENT GUIDANCE INDICATING BETTER CHANCES RESIDING ACROSS NORTHERN ILLINOIS INTO EARLY TUESDAY MORNING. HAVE NOT GONE OVERLY EXCITED WITH POPS DURING THIS TIME FRAME AS THE ECMWF REMAINS THE OUTLIER KEEPING A SURFACE LOW AND FORCING/PRECIP OFF TO THE WEST FOR MOST OF MONDAY AND MONDAY NIGHT. IF THIS WERE TO COME INTO FRUITION...THAN DRIER CONDITIONS WOULD BE OBSERVED MONDAY NIGHT WITH PRECIP DELAYED UNTIL TUESDAY. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * COVERAGE/TIMING OF THUNDERSTORMS EARLY THIS MORNING. * WIND SHIFT TO NORTHEAST BY LATE MORNING/MID-DAY. * POTENTIAL FOR PERIOD OF MVFR CEILINGS 1500-2000 FT LATE MORNING TO MID-AFTERNOON. RATZER //DISCUSSION...UPDATED 06Z... INITIAL CONCERN THIS MORNING IS WITH POTENTIAL FOR THUNDERSTORMS TO AFFECT TERMINALS DURING THE PRE-DAWN HOURS. AREA OF ELEVATED CONVECTION OVER FAR WESTERN IL AND NORTHEAST IA IS SLOWLY PROPAGATING TO THE EAST-SOUTHEAST AND WOULD LIKELY SKIRT SOUTH OF TERMINALS LATER THIS AM. NEW DEVELOPMENT CONTINUES TO OCCUR ON THE NORTHERN FRINGE OF THE CONVECTIVE COMPLEX ACROSS NORTHEAST IA HOWEVER...AND SEVERAL HIGH RES EXPLICIT CONVECTION MODELS CONTINUE TO DEPICT CONTINUED DEVELOPMENT INTO FAR NORTHERN IL TOWARD 09-10Z. THEREFORE HAVE MAINTAINED A BRIEF TEMPO MENTION FOR TS WITH SOME MINOR TIMING ADJUSTMENTS BASED ON RADAR EXTRAPOLATION PARTICULARLY FOR KRFD. ONCE MORNING STORMS MOVE OFF TO THE EAST...NEXT CONCERN IS WINDS SHIFTING TO THE NORTHEAST AND THE POTENTIAL FOR A PERIOD OF MVFR CEILINGS. GUIDANCE CONTINUES TO INDICATE WIND SHIFT BY VERY LATE MORNING/MID-DAY AS WEAK SURFACE WAVE MOVES EAST AND REINFORCING COLD FRONT SAGS SOUTH ACROSS TERMINALS. FORECAST SOUNDINGS DEPICT MOIST LAYER 1500-2000 FT IN COOL ADVECTION BENEATH INVERSION ALOFT. FORECAST SOUNDINGS INDICATE ENOUGH DRYING TAKES PLACE BY MID-LATE AFTERNOON TO SCATTER CLOUDS. WINDS...SOUTHEAST LESS THAN 10 KTS AT TAF ISSUANCE EXPECTED TO BECOME SOUTH OVERNIGHT...THEN LIGHT WESTERLY AFTER SUNRISE. AFOREMENTIONED FRONT THEN SAGS THROUGH WITH SHIFT TO THE NORTHEAST BY LATE MORNING OR SO...WITH GUSTS TO 15 KT POSSIBLE IN DEEPER MIXING WITH LOW LEVEL COLD ADVECTION. RATZER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE THUNDERSTORMS WILL AFFECT TRACON AIRSPACE...BUT MEDIUM CONFIDENCE IN DIRECT IMPACT ON INDIVIDUAL TERMINALS. * HIGH CONFIDENCE IN WIND TRENDS THROUGH PERIOD. * MEDIUM CONFIDENCE IN PERIOD OF 1500-2000 FT CIGS LATE MORNING INTO THIS AFTERNOON. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR WITH CHANCE TSRA MONDAY NIGHT. TUESDAY...VFR WITH CHANCE SHRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. RATZER && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1234 AM CDT SUN APR 1 2012 .DISCUSSION... 908 PM CDT SOME MINOR CHANGES TO POPS AND WX FOR TONIGHT. MAINLY DELAYING ARRIVAL OF THREAT OF SHRA AND TSRA UNTIL LATER TONIGHT AND REDUCING POPS OVER FAR NE IL FOR OVERNIGHT. RADAR COMPOSITE SHOWS WEAK ECHOES TO THE W THRU N OF THE LOCAL AREA WHERE INITIAL WAA AND RESULTING UVV AT MAINLY MID LEVELS OCCURRING. EXPECT THESE ECHOES...ALREADY MOSTLY VIRGA UPSTREAM WITH FEW IF ANY METARS REPORTING ANY PRECIP...WILL CONTINUE TO DRY UP AS THEY MOVE INTO INCREASINGLY DRY MID AND LOW LEVELS. A THUNDERSTORM DEVELOPED JUST NE OF DSM AROUND 0030Z AND ARE SLOWLY INCREASING IN NUMBER AS THEY MOVE ENE-E. THESE TSRA ARE WHERE BETTER MOISTURE IN THE 850 TO 800 HPA LAYER IS IN PLACE...WHERE WEAK SURFACE CONVERGENCE IS OCCURRING...WHERE NOSE OF 45 KT SOUTHWESTERLY JET AT 5 TO 6 K FT AGL SHOWN BY KDMX VAD WIND PROFILE IS LOCATED...AND JUST AHEAD OF WEAK MID LEVEL SHORT WAVE TROF MOVING OVER CENTRAL IA. CHALLENGE TO FORECAST IS HOW EXTENSIVE FURTHER TSRA DEVELOPMENT WILL BE AND WHERE AREA OF STORMS IS LIKELY TO MOVE OVERNIGHT. LATEST RUC13 RUN INDICATES A RATHER SMALL AREA OF MID LEVEL ISENTROPIC LIFT CURRENTLY OVER CENTRAL IA MOVES THIS AREA EASTWARD TO E CENTRAL IA 04-06Z...AND THEN SOUTHEASTWARD ACROSS N CENTRAL IL TO THE CENTRAL IL-IND BORDER BY 12Z. THIS APPEARS TO BE BEST TRACK FOR THE ELEVATED TSRA THAT IS EXPECTED TO BE MAINTAINED THROUGH THE OVERNIGHT BY THE LLJ...THE MID LEVEL SHORT WAVE AND STEEPENING MID LEVEL LAPSE RATES. EXPECT RATHER SMALL AREA OF TSRA AS MOISTURE WILL BE MARGINAL SO ONLY ANTICIPATE ACTIVITY WHERE FORCING FACTORS ARE MAXIMIZED DURING THE OVERNIGHT. TRS //PREV DISCUSSION... 317 PM CDT MAIN FORECAST ISSUES/CONCERNS FOR THE REMAINDER OF THE WEEKEND ARE WITH CHANCES FOR SHOWERS/THUNDERSTORMS LATE TONIGHT INTO SUNDAY MORNING...AS WELL AS TEMPERATURE TRENDS SUNDAY. WITH THE LOW LEVEL CLOUD COVER TODAY MASKING THE FACT THAT HIGH PRESSURE IS OVERHEAD...RELATIVELY QUIET CONDITIONS HAVE BEEN IN PLACE FOR ALL OF TODAY. ALTHOUGH...OVER THE LAST COUPLE OF HOURS SEVERAL HOLES DEVELOPED WITHIN THIS LOW LEVEL MOISTURE. A WARM SUN AND DRIER AIR ALOFT HAS ALLOWED FOR THESE HOLES TO CONTINUE TO EXPAND WITH SOME AREAS ACROSS THE SOUTHERN CWA OBSERVING SUNNY TO PARTLY CLOUDY SKIES. WITHIN THESE AREAS OF BETTER SOLAR INSOLATION...TEMPS HAVE QUICKLY RISEN INTO THE 50S WITH SOME AREAS OBSERVING SOME PLEASANT CONDITIONS AS RATHER LIGHT FLOW REMAINS IN PLACE. EXPECT THIS LOW CLOUD SHIELD TO CONTINUE TO ERODE WITH TIME LATE THIS AFTERNOON AND EARLY EVENING BUT WITH SOME MID AND HIGH LEVEL CLOUD COVER TO PUSH OVERHEAD. THIS IN ITSELF SHOULD PROVIDE PARTLY CLOUDY SKIES FOR TONIGHT...BUT WITH PRECIP CHANCES LATER TONIGHT TO POSSIBLY BRING MORE CLOUDY CONDITIONS MORE TOWARDS EARLY SUNDAY MORNING. LATEST GUIDANCE CONTINUES TO INDICATE SHOWERS AND THUNDERSTORMS DEVELOPING TONIGHT ACROSS EASTERN IOWA AND SHIFTING EAST/SOUTHEAST ACROSS A PORTION OF THE CWA THROUGH SUNDAY MORNING. ALL GUIDANCE IS INDICATING THIS POSSIBILITY BUT WITH SOME VARIABILITY STILL REMAINING WITH REGARDS TO EXACT TIMING AND PLACEMENT/TRACK. WITH BACKING 850MB FLOW...A WARMER AND MORE MOIST AIR MASS LOCATED ACROSS THE CENTRAL PLAINS WILL ADVECT NORTH/NORTHEAST WITH TIME TONIGHT BRINGING HIGHER DEW POINT AIR TO THE REGION. NORTHWEST FLOW ALOFT WILL STEER A MID LEVEL IMPULSE AND ATTENDANT SURFACE TROUGH OUT OF THE NORTHERN PLAINS THIS EVENING...AND HELP TO INITIATE CONVECTION ALONG A LOW LEVEL BAROCLINIC ZONE DRAPED ACROSS THE REGION. WITH LOW LEVEL FLOW FEEDING HIGHER THETA E AIR OVER THIS BOUNDARY AND INTO ANY DEVELOPING PRECIP...THIS AREA OF CONVECTION COULD SEE SOME EXPANSION IN COVERAGE AS IT SHIFTS EAST/SOUTHEAST THROUGH THE CWA EARLY SUNDAY MORNING. ALTHOUGH...GUIDANCE CONTINUES TO STRUGGLE WITH EXACT TIMING OF WHEN CONVECTION WILL DEVELOP AND WHERE THIS DEVELOPING AREA OF PRECIPITATION WILL PROGRESS THROUGH. DUE TO THIS UNCERTAINTY STILL IN PLACE...HAVE NOT MADE MANY CHANGES TO THE GOING POP GRIDS FOR TONIGHT KEEPING HIGH CHANCE POPS FOR MUCH OF THE CWA AFTER THE MIDNIGHT TIME FRAME THROUGH MID MORNING SUNDAY. THIS IS BASED ON THE LIKELIHOOD THAT CONVECTION SHOULD BEGIN TO DEVELOP OVER IOWA ONCE WE DECOUPLE AND THE LLJ RAMPS UP...WHICH SHOULD BE AROUND THE 3Z-6Z TIME FRAME. SOME HI RES DATA IS SHOWING THE POSSIBILITY OF AN MCS DEVELOPING AND QUICKLY SHIFTING THROUGH THE REGION SUNDAY MORNING. HAVE NOT COMPLETELY THROWN THIS OUT AS A POSSIBILITY...WITH DECENT LOW LEVEL SHEAR TO BE PRESENT ACROSS THE REGION. A LIMITING FACTOR WILL BE THE AMOUNT OF INSTABILITY PRESENT OVER NORTHERN ILLINOIS AND NORTHWEST...WHICH AM CURRENTLY LEANING MORE ON THE SREF MUCAPE OUTPUT WHICH IS SHOWING WEAKER INSTABILITY PRESENT BY EARLY SUNDAY MORNING LIMITING MORE ROBUST CONVECTION...WITH OTHER GUIDANCE OF COURSE ALSO VARYING TO THIS AMOUNT. SO WITH ANY PRECIP WHICH MOVES THROUGH THE AREA LATE TONIGHT AND EARLY SUNDAY MORNING...A MORE LIKELY SCENARIO WILL BE FOR THIS TO BE AN UNORGANIZED AREA OF SHOWERS AND ELEVATED THUNDERSTORMS WITH LITTLE CHANCES FOR SEVERE WEATHER...HAIL/WIND. ONLY AN ISOLATED THREAT OF HAIL COULD BE OBSERVED MAINLY FOR THE WESTERN CWA WHERE BETTER INSTABILITY AND STRONGER EFFECTIVE BULK SHEAR WILL RESIDE. EVEN IF A MORE ORGANIZED MCS COULD DEVELOP...WOULD EXPECT IT TO FOLLOW THE HIGHER SURFACE DEW POINT AIR AND BETTER INSTABILITY WHICH WOULD MORE THAN LIKELY BE SITUATED TO THE SOUTH OF THE CWA. THUS...ONCE AGAIN KEEPING ANY THREAT FOR SEVERE WEATHER JUST OUTSIDE OF THE CWA. THIS SITUATION WARRANTS CONTINUED MONITORING...AND WILL MAINTAIN A MENTION FOR THE CHANCES FOR THUNDERSTORMS TONIGHT IN THE HWO. ANY LINGERING SHOWERS/THUNDERSTORMS SHOULD EXIT THE CWA BY MID DAY WITH PARTLY CLOUDY TO SUNNY CONDITIONS EXPECTED THROUGH THE AFTERNOON. THE EXTENT OF THE MORNINGS PRECIP WILL DEFINITELY PLAY A KEY ROLE WITH MAX TEMPS ON SUNDAY WITH PERSISTENT WAA ADVECTING A WARMER AIR MASS OVERHEAD. AS SURFACE WARM FRONT TRIES TO LIFT NORTHEAST ACROSS THE CWA DURING THE DAY SUNDAY...IT WILL ACTUALLY BEGIN TO RETREAT AS A COLD FRONT WITH COOLER LOW LEVEL AIR WORKING ITS WAY BACK WEST ACROSS THE CWA LATE IN THE AFTERNOON AND EARLY EVENING. SO OUTSIDE OF PRECIP TRENDS POSSIBLY AFFECTING TEMP TRENDS SUNDAY...PLACEMENT OF THIS BOUNDARY AND MOVEMENT WILL BE KEY IN DEFINING MAX TEMPS FOR SUNDAY. DID BRING DOWN TEMPS A TAD FROM GOING FORECAST BUT HAVE KEPT THE WEST/SOUTHWEST CWA WARMER THAN THE EAST WITH AREAS STILL TO POSSIBLY REACH THE 80 MARK...AND AREAS ACROSS THE EASTERN CWA TO REACH THE LOWER 70S WITH 60S EXPECTED FOR AREAS NEAR THE LAKE. HAVE ADDED SLIGHT CHANCE POPS FOR THE SOUTHEAST PORTION OF THE CWA FOR SUNDAY AFTERNOON WHERE BETTER FOCUS AND UPPER LEVEL SUPPORT COULD PROVIDE FOR DEVELOPMENT OF THUNDERSTORMS. STRONG UPPER LEVEL RIDGING WILL OCCUR ON MONDAY WITH MID AND UPPER LEVEL FLOW BECOMING RATHER WEAK. THIS WEAK FLOW COINCIDING WITH A FORECASTED CLOSED UPPER LEVEL LOW TRACKING THROUGH THE SOUTHERN US WILL PROVIDE A TRICKY FORECAST THROUGH THE REMAINDER OF THE WEEK WITH THE ANTICIPATION FOR GUIDANCE TO CONTINUE TO STRUGGLE WITH PLACEMENT OF LOW LEVEL FEATURES AND INEVITABLE PRECIP. ALTHOUGH...THERE DOES APPEAR TO BE BETTER CHANCES FOR OBSERVING CONVECTION MONDAY NIGHT. BETTER FORCING AS WELL AS INSTABILITY LOOK TO BE IN PLACE FOR THE DEVELOPMENT OF POSSIBLY MORE ORGANIZED CONVECTION...WITH CURRENT GUIDANCE INDICATING BETTER CHANCES RESIDING ACROSS NORTHERN ILLINOIS INTO EARLY TUESDAY MORNING. HAVE NOT GONE OVERLY EXCITED WITH POPS DURING THIS TIME FRAME AS THE ECMWF REMAINS THE OUTLIER KEEPING A SURFACE LOW AND FORCING/PRECIP OFF TO THE WEST FOR MOST OF MONDAY AND MONDAY NIGHT. IF THIS WERE TO COME INTO FRUITION...THAN DRIER CONDITIONS WOULD BE OBSERVED MONDAY NIGHT WITH PRECIP DELAYED UNTIL TUESDAY. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * COVERAGE/TIMING OF THUNDERSTORMS EARLY THIS MORNING. * WIND SHIFT TO NORTHEAST BY LATE MORNING/MID-DAY. * POTENTIAL FOR PERIOD OF MVFR CEILINGS 1500-2000 FT LATE MORNING TO MID-AFTERNOON. RATZER //DISCUSSION...UPDATED 06Z... INITIAL CONCERN THIS MORNING IS WITH POTENTIAL FOR THUNDERSTORMS TO AFFECT TERMINALS DURING THE PRE-DAWN HOURS. AREA OF ELEVATED CONVECTION OVER FAR WESTERN IL AND NORTHEAST IA IS SLOWLY PROPAGATING TO THE EAST-SOUTHEAST AND WOULD LIKELY SKIRT SOUTH OF TERMINALS LATER THIS AM. NEW DEVELOPMENT CONTINUES TO OCCUR ON THE NORTHERN FRINGE OF THE CONVECTIVE COMPLEX ACROSS NORTHEAST IA HOWEVER...AND SEVERAL HIGH RES EXPLICIT CONVECTION MODELS CONTINUE TO DEPICT CONTINUED DEVELOPMENT INTO FAR NORTHERN IL TOWARD 09-10Z. THEREFORE HAVE MAINTAINED A BRIEF TEMPO MENTION FOR TS WITH SOME MINOR TIMING ADJUSTMENTS BASED ON RADAR EXTRAPOLATION PARTICULARLY FOR KRFD. ONCE MORNING STORMS MOVE OFF TO THE EAST...NEXT CONCERN IS WINDS SHIFTING TO THE NORTHEAST AND THE POTENTIAL FOR A PERIOD OF MVFR CEILINGS. GUIDANCE CONTINUES TO INDICATE WIND SHIFT BY VERY LATE MORNING/MID-DAY AS WEAK SURFACE WAVE MOVES EAST AND REINFORCING COLD FRONT SAGS SOUTH ACROSS TERMINALS. FORECAST SOUNDINGS DEPICT MOIST LAYER 1500-2000 FT IN COOL ADVECTION BENEATH INVERSION ALOFT. FORECAST SOUNDINGS INDICATE ENOUGH DRYING TAKES PLACE BY MID-LATE AFTERNOON TO SCATTER CLOUDS. WINDS...SOUTHEAST LESS THAN 10 KTS AT TAF ISSUANCE EXPECTED TO BECOME SOUTH OVERNIGHT...THEN LIGHT WESTERLY AFTER SUNRISE. AFOREMENTIONED FRONT THEN SAGS THROUGH WITH SHIFT TO THE NORTHEAST BY LATE MORNING OR SO...WITH GUSTS TO 15 KT POSSIBLE IN DEEPER MIXING WITH LOW LEVEL COLD ADVECTION. RATZER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE THUNDERSTORMS WILL AFFECT TRACON AIRSPACE...BUT MEDIUM CONFIDENCE IN DIRECT IMPACT ON INDIVIDUAL TERMINALS. * HIGH CONFIDENCE IN WIND TRENDS THROUGH PERIOD. * MEDIUM CONFIDENCE IN PERIOD OF 1500-2000 FT CIGS LATE MORNING INTO THIS AFTERNOON. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR WITH CHANCE TSRA MONDAY NIGHT. TUESDAY...VFR WITH CHANCE SHRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. RATZER && .MARINE... 115 PM CDT WINDS WILL TURN SOUTHERLY AND GRADUALLY INCREASE ACROSS LAKE MI TONIGHT AS HIGH PRESSURE MOVES EAST FROM THE CENTRAL GREAT LAKES. LOW PRESSURE WILL EVOLVE EASTWARD ACROSS THE LAKE ON SUNDAY MORNING. AN ASSOCIATED COLD FRONT WILL SLIP SOUTH AS THIS OCCURS...TURNING WINDS NORTHERLY ACROSS THE LAKE. THIS FRONT WILL LIKELY MOVE ACROSS THE NEARSHORE AREAS OF IL AND IN DURING THE EARLY TO MID AFTERNOON ON SUNDAY. HIGH PRESSURE WILL BRIEFLY PREVAIL ON SUNDAY NIGHT BEFORE ANOTHER LOW MOVES EAST ACROSS IOWA INTO NORTHERN ILLINOIS. WINDS ARE EXPECTED TO TURN BACK SOUTHEAST AHEAD OF THIS FEATURE ON MONDAY AFTERNOON...WITH SOME GUSTS UP TO 25 KT...INCLUDING POSSIBLY IN THE ILLINOIS NEAR SHORE AREAS. BEHIND THE LOW PASSAGE LATE MONDAY NIGHT INTO EARLY TUESDAY...THE WINDS WILL ONCE AGAIN SWING BACK NORTHERLY. HIGH PRESSURE IS THEN FORECAST TO ENCOMPASS MUCH OF THE LAKE WEDNESDAY THROUGH FRIDAY...THOUGH CONFIDENCE IN THIS IS FAIRLY LOW DUE TO A CLOSED UPPER LOW IN THE CENTRAL PLAINS WHICH COULD MEANDER CLOSE ENOUGH TO CAUSE SLIGHTLY STRONGER WINDS. OVERALL AT THIS TIME...NO LONG-LIVED GUSTY OR HIGH WAVE PERIODS ARE EXPECTED IN THE NEXT WEEK. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
401 AM EDT SUN APR 1 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS...A WEAK FRONTAL SYSTEM MOVING THROUGH COULD BRING CHANCES FOR THUNDERSTORMS ACROSS THE AREA LATE TONIGHT INTO SUNDAY. BY SUNDAY NIGHT UPPER RIDGING SHOULD REBUILD AND DRY THE WEATHER OUT THROUGH MONDAY...BUT BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM WILL APPROACH AND STALL OUT AND BRING THUNDERSTORM CHANCES FOR MONDAY NIGHT THROUGH THURSDAY. MORE UPPER RIDGING WILL DRY THINGS OUT FOR THE WEEKEND. && .NEAR TERM /OVERNIGHT/... LARGE AREA OF LOW STRATUS HAS FINALLY SHIFTED EAST WITH ONLY FAR NORTHEASTERN COUNTIES STILL UNDERNEATH THE DECK. REMAINDER OF THE FORECAST AREA HAD BECOME PARTLY CLOUDY WITH MID AND HIGH LEVEL CLOUDS DRIFTING ACROSS THE REGION. QUITE A RANGE OF TEMPERATURES EXISTED ACROSS THE FORECAST AREA AS OF 00Z...FROM MID 40S OVER THE NORTHEAST WHERE SKIES HAD BEEN CLOUDY ALL DAY TO MID 60S IN THE LOWER WABASH VALLEY. FOCUS FOR THE OVERNIGHT IS POTENTIAL FOR CONVECTION TO IMPACT WESTERN COUNTIES PRIOR TO DAYBREAK. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE DEVELOPMENT OF SCATTERED CONVECTION OVER EASTERN IOWA/WESTERN ILLINOIS SHORTLY AFTER MIDNIGHT AS AN UPPER LEVEL DISTURBANCE MOVES INTO THE REGION. PRESENCE OF A 35KT LOW LEVEL JET AND AXIS OF ELEVATED INSTABILITY SHOULD FURTHER CONTRIBUTE TO CONVECTIVE DEVELOPMENT IN THESE AREAS. STEERING FLOW ALOFT WOULD SUGGEST THAT CONVECTION WILL MOVE SOUTHEAST AND POTENTIALLY MIGRATE INTO THE NORTHERN WABASH VALLEY LATE TONIGHT. HAVE CHOSEN TO EXPAND LOW CHANCE POPS TO ENCOMPASS PORTIONS OF THE FORECAST AREA WEST OF A KOKOMO TO INDY METRO TO TERRE HAUTE LINE BETWEEN 09-12Z. HRRR GUIDANCE SUGGESTIVE OF LEADING EDGE OF CONVECTION ARRIVING INTO THESE AREAS SHORTLY BEFORE DAYBREAK. WHILE STORMS SHOULD BE WEAKENING BY THE TIME THEY ARRIVE IN CENTRAL INDIANA AS THE ENVIRONMENT WILL BE LESS FAVORABLE... POTENTIAL FOR STRONGER CELLS TO PRODUCE SMALL HAIL. WILL CONTINUE TO HIGHLIGHT IN THE HWO. LOWERED TEMPS A DEGREE OR TWO OVERNIGHT BASED ON CURRENT OBS...AND ADJUSTED TIMING AS LOWS LIKELY TO BOTTOM OUT BETWEEN 06 AND 08Z BEFORE ANY STORMS ARRIVE. ZONE AND GRID UPDATES OUT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT ON THE SHORT TERM SO WILL USE A CONSENSUS GENERALLY...BUT THOUGHT EARLY ON THE NAM WAS A LITTLE OVERZEALOUS IN POPS AND PRECIP ARRIVAL WITH THE SUNDAY SYSTEM SO THERE WILL LEAN TOWARD THE GFS/ECMWF/SREFS. COULD HAVE AN MCS ARRIVING IN THE NORTHWEST TO START OUT SUNDAY. VERY WEAK UPPER FORCING WITH A LITTLE SHORTWAVE MOVING THROUGH BUT ISENTROPIC LIFT SHOULD BE GOING THROUGH THE DAY ON SUNDAY. INSTABILITY WILL INCREASE THROUGH THE DAY SO THAT MIXED LAYER CAPES OF 1000 TO 1500 OR SO WILL BE IN PLACE ACROSS THE EAST BY THE AFTERNOON. MARGINAL SHEAR /BOTH DIRECTIONAL AND SPEED/ WILL BE AVAILABLE AS WELL DURING THE AFTERNOON...AND THUS THE INCLUSION OF A SLIGHT RISK FOR SEVERE WEATHER ACROSS MUCH OF THE EASTERN COUNTIES FOR THAT TIME. ALSO HAVE MID LEVEL LAPSE RATES AROUND 7-8C SO EXPECT THE MAIN THREAT TO BE LARGE HAIL. LEFT A SLIGHT CHANCE IN THE FAR EAST THROUGH 3Z AS SYSTEM IS MOVING OUT OF THE AREA. UPPER RIDGING BUILDS BACK IN AND KEPT POPS OUT THROUGH MONDAY. BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM MOVES IN TO NORTHERN ILLINOIS AND POSSIBLY NORTHERN INDIANA. THIS SURFACE LOW AND ISENTROPIC LIFT WILL SERVE AS THE MAIN FORCING MECHANISMS WITHOUT MUCH IN THE WAY OF UPPER FORCING AVAILABLE. WILL HAVE A CHANCE FOR THUNDERSTORMS MONDAY NIGHT AND INTO TUESDAY WITH THIS...WITH HIGHER CHANCES ON TUESDAY WITH THE LOW PASSING OVER THE AREA. FOR HIGH TEMPERATURES GENERALLY STUCK TOWARD THE WARMER END OF THE GUIDANCE ENVELOPE BASED ON RECENT VERIFICATION...AND COULD SEE A DECENT GRADIENT ACROSS THE AREA ON TUESDAY. FOR LOWS WENT A BIT WARMER THAN A CONSENSUS BASED ON EXPECTED CLOUD COVER AND FOR MONDAY NIGHT STUCK NEAR THE WET BULB TEMPERATURES WITH POTENTIAL FOR RAIN. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... EUROPEAN MODEL BECOMES MUCH COLDER THAN GFS AT 850 MILLIBARS LATE IN PERIOD. OVERALL EUROPEAN MORE CONSISTENT WITH CANADIAN AND BRITISH MODELS IN DEVELOPING A VORTEX OVER THE NORTHEAST STATES THAT WILL DRAW RELATIVELY CHILLY AIR INTO INDIANA. FORTUNATELY...ALL BLEND MODEL SEEMS TO CAPTURE THIS FAIRLY WELL WITH HIGHS LOWER 60S AND LOWS LOWER 40S LATE IN THE PERIOD. DID NOT SEE NEED TO CHANGE ALL BLEND INITIALIZATION. ALTHOUGH EUROPEAN AND GFS MUCH DIFFERENT IN STRENGTH...THEIR PHASE IS NOT THAT DIFFERENT. WHILE THIS RESULTS IN BIG DIFFERENCES FOR TEMPERATURES...TIMING OF PRECIPITATION APT TO BE CLOSER. ALL BLEND SEEMS TO CAPTURE THIS WITH QUITE LOW POPS FRIDAY AND SATURDAY IN PARTICULAR. NO NEED TO CHANGE INITIALIZATION MUCH. && .AVIATION /DISCUSSION FOR THE 010900Z TAF UPDATE/... EARLIER FORECAST ON TRACK OVERALL...BUT TUNING WILL BE NEEDED FOR PRECISE TIMING AS SHOWERS AND THUNDERSTORMS MOVE IN FROM THE WEST AND NORTH. CONFIDENCE IS LOW SINCE EXACT CONDITIONS AT ANY ONE TERMINAL COULD CHANGE GREATLY OVER SHORT PERIODS. MVFR CONDITIONS IN TSRA POSSIBLE THROUGH 15Z...THEN EXPECT A RETURN TO VFR FOR THE REMAINDER OF SUNDAY. AREA OF TSRA ACROSS NORTHWEST ILLINOIS WILL CONTINUE TO SHIFT SOUTHEAST TOWARD THE SITES. QUESTIONS ARISE IN HOW WELL THEY WILL HOLD TOGETHER AS UPPER SUPPORT WILL FIGHT WITH POOR INSTABILITY IN THE LOWER LEVELS. FOR NOW WILL JUST GO WITH VCSH AND CB MENTION...BUT WILL HAVE TO KEEP A CLOSE EYE ON TSRA EVOLUTION. TEMPO GROUPS MAY BE NEEDED FOR SHORT TIME IN TAFS. TSRA THREAT SHOULD DIMINISH BY 15Z. UNCERTAINTY REMAINS ON ANY LINGERING CLOUD COVER FROM TSRA...BUT EXPECT BKN CU TO DEVELOP IF THERE IS SUNSHINE. THUS JUST KEPT BKN060 DURING THE DAY SUNDAY. ADDITIONAL CONVECTION MAY DEVELOP SUNDAY AFTERNOON...BUT THAT IS TOO FAR OUT TO MENTION IN TAFS AT THE MOMENT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....JK AVIATION...JK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
317 AM EDT SUN APR 1 2012 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS...A WEAK FRONTAL SYSTEM MOVING THROUGH COULD BRING CHANCES FOR THUNDERSTORMS ACROSS THE AREA LATE TONIGHT INTO SUNDAY. BY SUNDAY NIGHT UPPER RIDGING SHOULD REBUILD AND DRY THE WEATHER OUT THROUGH MONDAY...BUT BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM WILL APPROACH AND STALL OUT AND BRING THUNDERSTORM CHANCES FOR MONDAY NIGHT THROUGH THURSDAY. MORE UPPER RIDGING WILL DRY THINGS OUT FOR THE WEEKEND. && .NEAR TERM /OVERNIGHT/... LARGE AREA OF LOW STRATUS HAS FINALLY SHIFTED EAST WITH ONLY FAR NORTHEASTERN COUNTIES STILL UNDERNEATH THE DECK. REMAINDER OF THE FORECAST AREA HAD BECOME PARTLY CLOUDY WITH MID AND HIGH LEVEL CLOUDS DRIFTING ACROSS THE REGION. QUITE A RANGE OF TEMPERATURES EXISTED ACROSS THE FORECAST AREA AS OF 00Z...FROM MID 40S OVER THE NORTHEAST WHERE SKIES HAD BEEN CLOUDY ALL DAY TO MID 60S IN THE LOWER WABASH VALLEY. FOCUS FOR THE OVERNIGHT IS POTENTIAL FOR CONVECTION TO IMPACT WESTERN COUNTIES PRIOR TO DAYBREAK. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE DEVELOPMENT OF SCATTERED CONVECTION OVER EASTERN IOWA/WESTERN ILLINOIS SHORTLY AFTER MIDNIGHT AS AN UPPER LEVEL DISTURBANCE MOVES INTO THE REGION. PRESENCE OF A 35KT LOW LEVEL JET AND AXIS OF ELEVATED INSTABILITY SHOULD FURTHER CONTRIBUTE TO CONVECTIVE DEVELOPMENT IN THESE AREAS. STEERING FLOW ALOFT WOULD SUGGEST THAT CONVECTION WILL MOVE SOUTHEAST AND POTENTIALLY MIGRATE INTO THE NORTHERN WABASH VALLEY LATE TONIGHT. HAVE CHOSEN TO EXPAND LOW CHANCE POPS TO ENCOMPASS PORTIONS OF THE FORECAST AREA WEST OF A KOKOMO TO INDY METRO TO TERRE HAUTE LINE BETWEEN 09-12Z. HRRR GUIDANCE SUGGESTIVE OF LEADING EDGE OF CONVECTION ARRIVING INTO THESE AREAS SHORTLY BEFORE DAYBREAK. WHILE STORMS SHOULD BE WEAKENING BY THE TIME THEY ARRIVE IN CENTRAL INDIANA AS THE ENVIRONMENT WILL BE LESS FAVORABLE... POTENTIAL FOR STRONGER CELLS TO PRODUCE SMALL HAIL. WILL CONTINUE TO HIGHLIGHT IN THE HWO. LOWERED TEMPS A DEGREE OR TWO OVERNIGHT BASED ON CURRENT OBS...AND ADJUSTED TIMING AS LOWS LIKELY TO BOTTOM OUT BETWEEN 06 AND 08Z BEFORE ANY STORMS ARRIVE. ZONE AND GRID UPDATES OUT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT ON THE SHORT TERM SO WILL USE A CONSENSUS GENERALLY...BUT THOUGHT EARLY ON THE NAM WAS A LITTLE OVERZEALOUS IN POPS AND PRECIP ARRIVAL WITH THE SUNDAY SYSTEM SO THERE WILL LEAN TOWARD THE GFS/ECMWF/SREFS. COULD HAVE AN MCS ARRIVING IN THE NORTHWEST TO START OUT SUNDAY. VERY WEAK UPPER FORCING WITH A LITTLE SHORTWAVE MOVING THROUGH BUT ISENTROPIC LIFT SHOULD BE GOING THROUGH THE DAY ON SUNDAY. INSTABILITY WILL INCREASE THROUGH THE DAY SO THAT MIXED LAYER CAPES OF 1000 TO 1500 OR SO WILL BE IN PLACE ACROSS THE EAST BY THE AFTERNOON. MARGINAL SHEAR /BOTH DIRECTIONAL AND SPEED/ WILL BE AVAILABLE AS WELL DURING THE AFTERNOON...AND THUS THE INCLUSION OF A SLIGHT RISK FOR SEVERE WEATHER ACROSS MUCH OF THE EASTERN COUNTIES FOR THAT TIME. ALSO HAVE MID LEVEL LAPSE RATES AROUND 7-8C SO EXPECT THE MAIN THREAT TO BE LARGE HAIL. LEFT A SLIGHT CHANCE IN THE FAR EAST THROUGH 3Z AS SYSTEM IS MOVING OUT OF THE AREA. UPPER RIDGING BUILDS BACK IN AND KEPT POPS OUT THROUGH MONDAY. BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM MOVES IN TO NORTHERN ILLINOIS AND POSSIBLY NORTHERN INDIANA. THIS SURFACE LOW AND ISENTROPIC LIFT WILL SERVE AS THE MAIN FORCING MECHANISMS WITHOUT MUCH IN THE WAY OF UPPER FORCING AVAILABLE. WILL HAVE A CHANCE FOR THUNDERSTORMS MONDAY NIGHT AND INTO TUESDAY WITH THIS...WITH HIGHER CHANCES ON TUESDAY WITH THE LOW PASSING OVER THE AREA. FOR HIGH TEMPERATURES GENERALLY STUCK TOWARD THE WARMER END OF THE GUIDANCE ENVELOPE BASED ON RECENT VERIFICATION...AND COULD SEE A DECENT GRADIENT ACROSS THE AREA ON TUESDAY. FOR LOWS WENT A BIT WARMER THAN A CONSENSUS BASED ON EXPECTED CLOUD COVER AND FOR MONDAY NIGHT STUCK NEAR THE WET BULB TEMPERATURES WITH POTENTIAL FOR RAIN. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... EUROPEAN MODEL BECOMES MUCH COLDER THAN GFS AT 850 MILLIBARS LATE IN PERIOD. OVERALL EUROPEAN MORE CONSISTENT WITH CANADIAN AND BRITISH MODELS IN DEVELOPING A VORTEX OVER THE NORTHEAST STATES THAT WILL DRAW RELATIVELY CHILLY AIR INTO INDIANA. FORTUNATELY...ALL BLEND MODEL SEEMS TO CAPTURE THIS FAIRLY WELL WITH HIGHS LOWER 60S AND LOWS LOWER 40S LATE IN THE PERIOD. DID NOT SEE NEED TO CHANGE ALL BLEND INITIALIZATION. ALTHOUGH EUROPEAN AND GFS MUCH DIFFERENT IN STRENGTH...THEIR PHASE IS NOT THAT DIFFERENT. WHILE THIS RESULTS IN BIG DIFFERENCES FOR TEMPERATURES...TIMING OF PRECIPITATION APT TO BE CLOSER. ALL BLEND SEEMS TO CAPTURE THIS WITH QUITE LOW POPS FRIDAY AND SATURDAY IN PARTICULAR. NO NEED TO CHANGE INITIALIZATION MUCH. && .AVIATION /DISCUSSION FOR THE 010600Z TAFS/... MVFR CONDITIONS IN FOG OR TSRA POSSIBLE THROUGH 15Z...THEN EXPECT A RETURN TO VFR FOR THE REMAINDER OF THE DAY ON SUNDAY. AREA OF TSRA ACROSS NORTHWEST ILLINOIS WILL CONTINUE TO SHIFT SOUTHEAST TOWARD THE SITES. QUESTIONS ARISE IN HOW WELL THEY WILL HOLD TOGETHER AS UPPER SUPPORT WILL FIGHT WITH POOR INSTABILITY IN THE LOWER LEVELS. FOR NOW WILL JUST GO WITH VCSH AND CB MENTION...BUT WILL HAVE TO KEEP A CLOSE EYE ON TSRA EVOLUTION. AT THE MOMENT CONFIDENCE IS LOW. TSRA/FOG THREAT SHOULD DIMINISH BY 15Z. UNCERTAINTY REMAINS ON ANY LINGERING CLOUD COVER FROM TSRA...BUT EXPECT BKN CU TO DEVELOP IF THERE IS SUNSHINE. THUS JUST KEPT BKN060 DURING THE DAY SUNDAY. ADDITIONAL CONVECTION MAY DEVELOP SUNDAY AFTERNOON...BUT THAT IS TOO FAR OUT TO MENTION IN TAFS AT THE MOMENT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....JK AVIATION...50/JK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1245 AM EDT SUN APR 1 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS...A WEAK FRONTAL SYSTEM MOVING THROUGH COULD BRING CHANCES FOR THUNDERSTORMS ACROSS THE AREA LATE TONIGHT INTO SUNDAY. BY SUNDAY NIGHT UPPER RIDGING SHOULD REBUILD AND DRY THE WEATHER OUT THROUGH MONDAY...BUT BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM WILL APPROACH AND STALL OUT AND BRING THUNDERSTORM CHANCES FOR MONDAY NIGHT THROUGH THURSDAY. MORE UPPER RIDGING WILL DRY THINGS OUT FOR THE WEEKEND. && .NEAR TERM /OVERNIGHT/... LARGE AREA OF LOW STRATUS HAS FINALLY SHIFTED EAST WITH ONLY FAR NORTHEASTERN COUNTIES STILL UNDERNEATH THE DECK. REMAINDER OF THE FORECAST AREA HAD BECOME PARTLY CLOUDY WITH MID AND HIGH LEVEL CLOUDS DRIFTING ACROSS THE REGION. QUITE A RANGE OF TEMPERATURES EXISTED ACROSS THE FORECAST AREA AS OF 00Z...FROM MID 40S OVER THE NORTHEAST WHERE SKIES HAD BEEN CLOUDY ALL DAY TO MID 60S IN THE LOWER WABASH VALLEY. FOCUS FOR THE OVERNIGHT IS POTENTIAL FOR CONVECTION TO IMPACT WESTERN COUNTIES PRIOR TO DAYBREAK. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE DEVELOPMENT OF SCATTERED CONVECTION OVER EASTERN IOWA/WESTERN ILLINOIS SHORTLY AFTER MIDNIGHT AS AN UPPER LEVEL DISTURBANCE MOVES INTO THE REGION. PRESENCE OF A 35KT LOW LEVEL JET AND AXIS OF ELEVATED INSTABILITY SHOULD FURTHER CONTRIBUTE TO CONVECTIVE DEVELOPMENT IN THESE AREAS. STEERING FLOW ALOFT WOULD SUGGEST THAT CONVECTION WILL MOVE SOUTHEAST AND POTENTIALLY MIGRATE INTO THE NORTHERN WABASH VALLEY LATE TONIGHT. HAVE CHOSEN TO EXPAND LOW CHANCE POPS TO ENCOMPASS PORTIONS OF THE FORECAST AREA WEST OF A KOKOMO TO INDY METRO TO TERRE HAUTE LINE BETWEEN 09-12Z. HRRR GUIDANCE SUGGESTIVE OF LEADING EDGE OF CONVECTION ARRIVING INTO THESE AREAS SHORTLY BEFORE DAYBREAK. WHILE STORMS SHOULD BE WEAKENING BY THE TIME THEY ARRIVE IN CENTRAL INDIANA AS THE ENVIRONMENT WILL BE LESS FAVORABLE... POTENTIAL FOR STRONGER CELLS TO PRODUCE SMALL HAIL. WILL CONTINUE TO HIGHLIGHT IN THE HWO. LOWERED TEMPS A DEGREE OR TWO OVERNIGHT BASED ON CURRENT OBS...AND ADJUSTED TIMING AS LOWS LIKELY TO BOTTOM OUT BETWEEN 06 AND 08Z BEFORE ANY STORMS ARRIVE. ZONE AND GRID UPDATES OUT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT ON THE SHORT TERM SO WILL USE A CONSENSUS GENERALLY...BUT THOUGHT EARLY ON THE NAM WAS A LITTLE OVERZEALOUS IN POPS AND PRECIP ARRIVAL WITH THE SUNDAY SYSTEM SO THERE WILL LEAN TOWARD THE GFS/ECMWF/SREFS. COULD HAVE AN MCS ARRIVING IN THE NORTHWEST TO START OUT SUNDAY. VERY WEAK UPPER FORCING WITH A LITTLE SHORTWAVE MOVING THROUGH BUT ISENTROPIC LIFT SHOULD BE GOING THROUGH THE DAY ON SUNDAY. INSTABILITY WILL INCREASE THROUGH THE DAY SO THAT MIXED LAYER CAPES OF 1000 TO 1500 OR SO WILL BE IN PLACE ACROSS THE EAST BY THE AFTERNOON. MARGINAL SHEAR /BOTH DIRECTIONAL AND SPEED/ WILL BE AVAILABLE AS WELL DURING THE AFTERNOON...AND THUS THE INCLUSION OF A SLIGHT RISK FOR SEVERE WEATHER ACROSS MUCH OF THE EASTERN COUNTIES FOR THAT TIME. ALSO HAVE MID LEVEL LAPSE RATES AROUND 7-8C SO EXPECT THE MAIN THREAT TO BE LARGE HAIL. LEFT A SLIGHT CHANCE IN THE FAR EAST THROUGH 3Z AS SYSTEM IS MOVING OUT OF THE AREA. UPPER RIDGING BUILDS BACK IN AND KEPT POPS OUT THROUGH MONDAY. BY MONDAY NIGHT ANOTHER FRONTAL SYSTEM MOVES IN TO NORTHERN ILLINOIS AND POSSIBLY NORTHERN INDIANA. THIS SURFACE LOW AND ISENTROPIC LIFT WILL SERVE AS THE MAIN FORCING MECHANISMS WITHOUT MUCH IN THE WAY OF UPPER FORCING AVAILABLE. WILL HAVE A CHANCE FOR THUNDERSTORMS MONDAY NIGHT AND INTO TUESDAY WITH THIS...WITH HIGHER CHANCES ON TUESDAY WITH THE LOW PASSING OVER THE AREA. FOR HIGH TEMPERATURES GENERALLY STUCK TOWARD THE WARMER END OF THE GUIDANCE ENVELOPE BASED ON RECENT VERIFICATION...AND COULD SEE A DECENT GRADIENT ACROSS THE AREA ON TUESDAY. FOR LOWS WENT A BIT WARMER THAN A CONSENSUS BASED ON EXPECTED CLOUD COVER AND FOR MONDAY NIGHT STUCK NEAR THE WET BULB TEMPERATURES WITH POTENTIAL FOR RAIN. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ENSEMBLES IN GENERAL AGREEMENT IN BRINGING A SYSTEM THAT IS PROGGED TO BE MOVING INTO THE WEST COAST SUNDAY ACROSS THE LOCAL AREA AROUND THE MIDDLE OF NEXT WEEK. ENSEMBLE TREND HAS BEEN TOWARDS CUTTING THIS SYSTEM OFF FROM THE MAIN WESTERLIES...AND TODAY THE MAJORITY OF THE ENSEMBLES POINT IN THIS DIRECTION...WITH THE EFFECTS OF THE CUTOFF AFFECTING THE AREA INTO THURSDAY. WILL GO WITH CHANCE POPS ON WEDNESDAY AND THURSDAY OVER MAINLY THE SOUTHERN ZONES...WHICH WILL BE CLOSER TO CUTOFF LOW. WILL CONTINUE WITH A DRY FORECAST FRIDAY AND SATURDAY AT THIS TIME WITH UPPER RIDGING MOVING THROUGH... ALTHOUGH SOME ENSEMBLES BRING A PRECIPITATION THREAT BACK INTO THE AREA BY NEXT SATURDAY. MAY NEED TO ADD POPS TO NEXT WEEKEND AT A LATER TIME IF FUTURE TRENDS POINT IN THAT DIRECTION. && .AVIATION /DISCUSSION FOR THE 010600Z TAFS/... MVFR CONDITIONS IN FOG OR TSRA POSSIBLE THROUGH 15Z...THEN EXPECT A RETURN TO VFR FOR THE REMAINDER OF THE DAY ON SUNDAY. AREA OF TSRA ACROSS NORTHWEST ILLINOIS WILL CONTINUE TO SHIFT SOUTHEAST TOWARD THE SITES. QUESTIONS ARISE IN HOW WELL THEY WILL HOLD TOGETHER AS UPPER SUPPORT WILL FIGHT WITH POOR INSTABILITY IN THE LOWER LEVELS. FOR NOW WILL JUST GO WITH VCSH AND CB MENTION...BUT WILL HAVE TO KEEP A CLOSE EYE ON TSRA EVOLUTION. AT THE MOMENT CONFIDENCE IS LOW. TSRA/FOG THREAT SHOULD DIMINISH BY 15Z. UNCERTAINTY REMAINS ON ANY LINGERING CLOUD COVER FROM TSRA...BUT EXPECT BKN CU TO DEVELOP IF THERE IS SUNSHINE. THUS JUST KEPT BKN060 DURING THE DAY SUNDAY. ADDITIONAL CONVECTION MAY DEVELOP SUNDAY AFTERNOON...BUT THAT IS TOO FAR OUT TO MENTION IN TAFS AT THE MOMENT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....JAS AVIATION...50/JK
AREA FORECAST DISCUSSION
NWS WICHITA KS
337 AM CDT SUN APR 1 2012 .DISCUSSION... TODAY-TONIGHT: UNSEASONABLY WARM TEMPERTURES ARE EXPECTED WITH FORECAST MAXES GETTING CLOSE TO RECORDS AT SEVERAL LOCATIONS. ANTICIPATE LOW CLOUDS WILL THIN/ERODE BY MIDDAY WITH TEMPERATURES BASED ON WARMER MODEL OUTPUT STATISTICS/BIASES FROM YESTERDAY. FAIR AMOUNT OF SPREAD IN SHORT TERM MODELS/MODEL OUTPUT STATISTICS WITH WIND SPEEDS DURING THE DAY...WITH SOME MODEL OUTPUT STATISTICS APPROACHING ADVISORY CRITERIA AT 2100 UTC. LOW CLOUDS MAY DEVELOP AGAIN TONIGHT IN SOUTHEAST KS MON-MON NIGHT: GOING TREND OF POPS MON AFTERNOON ALONG SAGGING FRONT STILL LOOKS ON TARGET. STILL FAIR AMOUNT OF WIGGLE ROOM WHERE BOUNDARY WILL BE WHEN INITIATION OCCURS...AND SHADED POPS BASED ON MODEL CONSENSUS. WHILE BOTH GFS/NAM SHOW GOOD INSTABILITY...DEEP LAYER SHEAR AND HODOGRAPHS ARE NOT FAVORABLE FOR SEVERE. HOWEVER GIVEN PROXIMITY TO UPPER LOW AND EFFECT OF EVEN SMALL CHANGES TO ITS TRACK...WILL CONTINUE MENTION OF STRONG STORMS IN HAZARDOUS WEATHER OUTLOOK FOR MON AFTERNOON-EVENING. VERY MILD TEMPERATURES ANTICIPATED MON NIGHT WITH WINDS STAYING UP A BIT AND INFLUX OF LOW LEVEL MOISTURE. TUE-WED: LATEST RUNS LESS LIKELY TO SUPPORT SIGNIFICANT DRY SLOT WHICH COULD SIGNIFICANTLY IMPACT POPS/TEMPERATURES. PRECIPITATION CHANCES SHOULD BE HIGHEST ON W-NW-NE SIDE OF UPPER LOW...AND SHADED HIGHEST POPS ACROSS CENTRAL KS. TEMPERATURES SOMEWHAT TRICKY WITH COMBO OF COLD AIR ADVECTION/CLOUDS AND PRECIPITATION. THU-SAT: ALTHOUGH TEMPERATURES WILL BE COOLER THIS PERIOD...VALUES WILL STILL BE ABOVE NORMAL. LATEST MODELS STILL HINTING AT SOME PRECIPITATION POTENTIAL ON FRI NIGHT/SAT WITH FRONT MOVING THROUGH THE AREA...ALTHOUGH THERE IS SOME QUESTION AS TO THE AMOUNT/DEPTH OF MOISTURE. -HOWERTON && .FIRE WEATHER... DESPITE UNSEASONBALY WARM TEMPERATURES AND INCREASING WINDS ON TODAY...THE GRASSLAND FIRE DANGER RISK IS EXPECTED TO BE ONLY SLIGHTLY ELEVATED DUE TO THE EARLY SPRING GREEN-UP.-HOWERTON && .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN CONCERN REMAINS POTENTIAL FOR LOW STRATUS. LEE TROUGH WILL ALLOW LIGHT SOUTH-SOUTHEASTERLY WINDS TO CONTINUE OVERNIGHT WITH INCREASING BOUNDARY LAYER MOISTURE. THIS SHOULD RESULT IN LIFR-IFR STRATUS DEVELOPMENT OVER MUCH OF THE AREA DURING THE EARLY AM HOURS SUNDAY. THIS IS SUPPORTED IN THE NAM...GFS...RUC...AND 3KM HRRR MODELS. FORECAST CONFIDENCE IS ABOVE AVERAGE GIVEN THE LOW STRATUS OCCURRENCE IN CENTRAL/SOUTHWEST OK AND NORTH CENTRAL TEXAS SATURDAY MORNING. THE STRATUS LOOKS TO BURN OFF TOWARD MIDDAY SUNDAY. BETTER MIXING AND NEAR FULL SUNSHINE SUNDAY AFTERNOON SHOULD RESULT IN SOUTHERLY GUSTS ~25 KT MOST OF THE AREA. JMC && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 85 63 80 54 / 0 0 20 60 HUTCHINSON 86 60 78 51 / 0 0 20 50 NEWTON 84 63 79 53 / 0 0 20 50 ELDORADO 84 66 82 55 / 0 0 20 50 WINFIELD-KWLD 86 65 85 57 / 0 0 20 60 RUSSELL 88 56 70 45 / 0 0 10 30 GREAT BEND 87 55 72 44 / 0 0 20 40 SALINA 87 61 76 50 / 0 0 20 40 MCPHERSON 86 61 77 50 / 0 0 20 50 COFFEYVILLE 87 68 88 62 / 0 10 10 40 CHANUTE 86 65 88 60 / 0 10 10 40 IOLA 86 65 88 59 / 0 10 10 30 PARSONS-KPPF 87 67 88 60 / 0 10 10 40 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...CORRECTED
NWS DODGE CITY KS
334 AM CDT SUN APR 1 2012 ...UPDATED SYNOPSIS/SHORT TERM/FIRE WEATHER/CLIMATE DISCUSSIONS... .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 333 AM CDT SUN APR 1 2012 .SYNOPSIS... ISSUED AT 333 AM CDT SUN APR 1 2012 THE APRIL 1 2012 00Z 300 HPA SYNOPTIC MAP SHOWED A LARGE ANTICYCLONIC CURVED JET EXTENDING ACROSS THE WESTERN UNITED STATES AND INTO THE CANADIAN PRAIRIE PROVINCES. A JET STREAK OF AROUND 130-140 KT WAS OBSERVED FROM KREV TO KBOI. AT 500 HPA, AN AMPLIFIED TROUGH ASSOCIATED WITH THE JET STREAK WAS LOCATED ACROSS THE PACIFIC NORTHWEST AND INTO NORTHERN CALIFORNIA. CONSIDERABLE COLD AIR ADVECTION WITH 500 HPA DELTA TEMPERATURES AROUND 10 DEG C WAS OBSERVED ACROSS THE PACIFIC NORTHWEST ALONG WITH SIGNIFICANT HEIGHT FALLS. MORE LOCALLY AND AT LOWER LEVELS, A WARM AND DRY PLUME AT 700 AND 850 HPA PREVAILED ACROSS THE HIGH PLAINS. AT THE SFC, A LOW PRESSURE CENTER WAS LOCATED ACROSS EASTERN COLORADO. A DRYLINE ASSOCIATED WITH THIS FEATURE WAS LOCATED ACROSS THE SOUTHERN HIGH PLAINS AS WELL. THIS MORNING: AS WITH LAST NIGHT, HAVE FOLLOWED HRRR GUIDANCE IN CONCERNING THE POTENTIAL FOR PATCHY FOG FORMATION THIS MORNING. THIS MODEL HAS BEEN TRENDING WELL AS SITES AROUND KANSAS AND OKLAHOMA HAVE BEEN REPORTING BR THROUGH THE OVERNIGHT HOURS. I DID, HOWEVER, TAKE A MORE CONSERVATIVE APPROACH AS FAR AS DENSE FOG IS CONCERNED AND STUCK WITH PATCHY RATHER THAN +FG AS THE WINDS HAVE REMAINED ELEVATED THIS MORNING, WHICH COULD LIMIT THE OVERALL FOG INTENSITY. RECENT LAMP GUIDANCE AND RUC VIS OUTPUT SEEMS TO AGREE WITH THIS APPROACH AS WELL. FOG CONCERNS WILL BE OVER BY MID MORNING IF NOT SOONER. TODAY: UNPLEASANTLY WARM TEMPERATURES ARE EXPECTED TODAY. I SAY UNPLEASANT BECAUSE IT WILL FEEL DOWN RIGHT "HOT" RELATIVE TO THE BEGINNING OF APRIL. I DID TAKE THE COOLER SIDE OF MOS GUIDANCE AS BOISE VERIFICATION STILL SHOWS A WARM BIAS FROM THE MODELS. ONE REASON AS SUGGESTED FROM YESTERDAYS DAY SHIFT IS THAT EVAPOTRANSPIRATION FROM A RECENT HEAVY RAINFALL EVENT IS SLOWING DOWN HEAT FLUXES. IN ADDITION, DEWPOINTS ARE RUNNING AROUND 60 DEG F THIS MORNING SO THE ATMOSPHERE DOES HAVE SOME MOISTURE WHICH WILL RETARD SENSIBLE HEATING. THESE DEWPOINTS WILL LOWER AS THE DRYLINE WILL MIX EAST THROUGH THE AFTERNOON. CONVECTION IS NOT EXPECTED ALONG THE DRYLINE AS UPPER LEVEL RIDGING CONTINUES AND SUBSIDE PREVAILS AHEAD OF A WESTERN TROUGH. SOME RECORDS COULD BE IN JEOPARDY TODAY WHICH HAS BEEN HIGHLIGHTED IN THE CLIMATE SECTION BELOW. ANOTHER CONCERN FOR TODAY IS WINDS. THE 00Z GFS IS STRONGER WITH 850 HPA WINDS COMPARED TO THE 00Z NAM. THE ATMOSPHERE WILL BECOME WELL MIXED THIS AFTERNOON IN THE WAKE OF THE DRYLINE, HOWEVER WINDS PER THE MESOSCALE MODELS ARE NOT THAT IMPRESSIVE AND USING MIX DOWN TECHNIQUES SHOWS THAT A MARGINAL OR SUB MARGINAL WIND ADVISORY SPEEDS ARE POSSIBLE ACROSS THE WESTERN AND CENTRAL SECTIONS OF THE CWFA TODAY. AS A RESULT, DID NOT ISSUE A WIND ADVISORY FOR TODAY. LASTLY, CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY WHICH IS ADDRESSED BELOW IN THE FIRE WEATHER SECTION. TONIGHT: WINDS WILL GRADUALLY VEER OVERNIGHT AHEAD OF AN APPROACHING SIGNIFICANT COLD FRONT. TEMPERATURES WILL BE MILD AND GENERALLY IN THE 40S DEG F WEST TO 50S DEG F EAST. NO PRECIPITATION IS EXPECTED DURING THIS TIME FRAME AS DYNAMICS WILL NOT ARRIVE UNTIL AS DESCRIBED IN THE LONG TERM SECTION. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 243 AM CDT SUN APR 1 2012 MODELS THIS MORNING REMAIN IN GOOD AGREEMENT WITH QUICKLY MOVING AN UPPER LEVEL TROUGH WHICH WAS LOCATED JUST OFF THE WEST COAST OF CALIFORNIA TO NEAR THE FOUR CORNERS REGION BY 06Z MONDAY. THIS UPPER LEVEL SYSTEM THEN DEEPENS AS IT CROSSES NEW MEXICO DURING THE DAY ON MONDAY. BY 00Z TUESDAY THE GFS, ECMWF, AND NAM ALL PLACE THIS UPPER LEVEL LOW NEAR EAST CENTRAL NEW MEXICO. AHEAD OF THIS DEEPENING UPPER LEVEL SYSTEM A COLD FRONT WILL BE MOVING SOUTH ACROSS WESTERN KANSAS DURING THE DAY AND BASED ON THE GFS AND NAM THIS FRONTAL BOUNDARY WILL BE LOCATED NEAR THE OKLAHOMA BORDER AND SOUTH CENTRAL KANSAS BY 00Z TUESDAY. BOTH MODELS THIS MORNING ARE IN GOOD AGREEMENT WITH CONVECTION DEVELOPING ALONG THIS COLD FRONT LATE DAY DESPITE THE DIFFERENCES IN THE LOCATION OF THIS FRONT MONDAY EVENING. THE CONVECTION LATE DAY DOES APPEAR REASONABLE GIVEN THE MOISTURE RETURN FORECAST AHEAD OF THIS FRONT, IMPROVING LOW LEVEL FORCING AND LATE DAY INSTABILITY. AS A RESULT WILL CONTINUE TO FAVOR KEEPING A MENTION OF LATE DAY STORMS ACROSS SOUTH CENTRAL KANSAS AFTER 21Z. DECENT MID LEVEL INSTABILITY AT 00Z TUESDAY AND CAPES ARE FORECAST TO BE AT OR ABOVE 2000 J/KG. MARGINAL SHEAR HOWEVER IS EXPECTED WITH 0-6KM SHEAR AT OR BELOW 30KTS. STILL GIVEN SOME LATE DAY HEATING AND IMPROVING FORCING ALONG THIS BOUNDARY DO THINK A FEW STORMS THAT DO DEVELOP ALONG THIS FRONT LATE DAY MAY BECOME SEVERE WITH HAIL UP TO QUARTER SIZE BEING THE MAIN HAZARD. NORTH/NORTHWEST OF THIS COLD FRONT LATE MONDAY GUSTY NORTHERLY WINDS ARE EXPECTED TO INCREASE INTO THE 25 TO 35 MPH RANGE AS AN AREA OF LOW PRESSURE AT THE SURFACE DEEPENS ALONG THIS COLD FRONT ACROSS THE PANHANDLE OF TEXAS. THIS WILL BEGIN TO USHER IN SOME COOLER AIR LATE IN THE DAY SO TEMPERATURES BEHIND THIS COLD FRONT ARE EXPECTED TO STRUGGLE INTO THE UPPER 60S TO LOWER 70S. AHEAD OF THIS FRONT LOWER 80S STILL APPEAR LIKELY. THE CHANCES FOR PRECIPITATION THEN SPREADS NORTHWARD ACROSS ALL OF WESTERN AND MUCH OF NORTH CENTRAL KANSAS MONDAY NIGHT AS THE UPPER LEVEL LOW BEGINS TO LOWLY MOVE EAST INTO THE PANHANDLE OF TEXAS AND WARM AIR ADVECTION AND MOISTURE IMPROVES ACROSS WESTERN KANSAS DURING THE OVERNIGHT HOURS MONDAY NIGHT. FROM TUESDAY THROUGH EARLY WEDNESDAY A SERIES OF UPPER LEVEL DISTURBANCES WILL ROTATE AROUND THIS UPPER LOW AS IT MOVES FROM THE PANHANDLE OF TEXAS INTO SOUTH CENTRAL KANSAS. MOISTURE AND LIFT (WARM AIR ADVECTION, ISENTROPIC LIFT, 850-700MB FRONTOGENESIS) CONTINUES SO HAVE THEREFORE RAISE PRECIPITATION CHANCES ACROSS THE ENTIRE AREA. BY LATE WEDNESDAY AN UPPER LEVEL SHORT WAVE RIDGE WILL BEGIN TO BUILD INTO THE ROCKIES AS THE UPPER LOW CONTINUES TO TRACK EASTWARD ACROSS EASTERN KANSAS. SKIES ARE EXPECTED TO CLEAR FROM WEST TO EAST AS THE PRECIPITATION ENDS. TEMPERATURES WEDNESDAY NIGHT HAS THE POTENTIAL TO FALL BACK TO NEAR FREEZING IF SKIES CLEAR QUICK ENOUGH AND WIND GO LIGHT BUT GIVEN THE TIMING ISSUES OF THE UPPER LOW HAVE DECIDED TO STAY CLOSE TO LATEST ALLBLEND. ON THURSDAY AND FRIDAY A WARMING TREND CAN BE EXPECTED ACROSS WESTERN KANSAS AS THE UPPER LEVEL RIDGE AXIS BUILDS EAST OUT INTO THE PLAINS AND WESTERLY DOWN SLOPE FLOW IMPROVES && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1201 AM CDT SUN APR 1 2012 TWO CONCERNS FOR THE 06Z TAFS. FOG AND WINDS. THE 01/02Z HRRR IS MOST AGGRESSIVE IN BRINGING DENSE FOG ACROSS SOUTH CENTRAL KANSAS BY MORNING. THIS MODEL WAS FAIRLY ACCURATE LAST NIGHT ALTHOUGH A LITTLE TOO LOW ON VIS. THE RUC ALSO SHOWS LOWERED VIS GENERALLY IN THE SAME AREA. DON`T HAVE ENOUGH CONFIDENCE FOR LIFR CIGS BUT HAVE LOWERED CIGS FROM VFR TO MVFR TO START OUT ON THE CONSERVATIVE SIDE SINCE THE HRRR OVERDID IT LAST NIGHT. SECOND CONCERN IS WINDS. HAVE INCREASED SW WINDS 20-25 KT WITH GUSTS TO 30-35 KT AS THE LEE SFC TROUGH STRENGTHENS TOMORROW AFTERNOON. && .FIRE WEATHER... ISSUED AT 333 AM CDT SUN APR 1 2012 AFTER COORDINATION WITH SURROUNDING WFO`S, HAVE CONTINUED THE RFW TODAY AND ADDED CLARK COUNTY IN. THE EASTERN COLUMN OF COUNTIES IS A BIT MARGINAL AS RH`S WILL BE IN THE 15 TO 17 PERCENT RANGE. DECIDED TO ERROR ON THE SIDE OF CAUTION AND KEEP THE COUNTIES IN THE WARNING AS TODAYS HIGHS WILL BE VERY WARM AND THE MODELS TYPICALLY UNDER FORECAST DEWPOINTS IN ASSOCIATION WITH A MIXING DRYLINE AND ADIABATIC COMPRESSIONAL WARMING. && .CLIMATE... ISSUED AT 333 AM CDT SUN APR 1 2012 A VERY ANOMALOUS DAY OF EXTREMELY WARM TEMPERATURES IS EXPECTED TODAY. POSITIVE TEMPERATURE DEVIATIONS OF 20 TO 30 DEGREES IS LIKELY ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS. SOME RECORDS COULD BE BROKEN TODAY. CLIMATE RECORDS IS AS FOLLOWS: RECORD (YEAR)..........................FORECAST HIGH FOR TODAY DODGE CITY: 88 (1940, 1964)............89 MEDICINE LODGE: 93 (1946)..............86 GARDEN CITY: 87 (1964).................90 ELKHART 89 (1946)......................90 && .PRELIMINARY POINT TEMPS/POPS... DDC 89 52 74 41 / 0 10 10 60 GCK 90 50 69 40 / 0 10 10 50 EHA 90 49 66 38 / 0 10 20 50 LBL 90 50 71 40 / 0 10 20 50 HYS 88 54 72 41 / 0 10 10 50 P28 86 57 82 51 / 0 10 40 60 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR KSZ030-043>045-061>064-074>078-084>088. && $$ SYNOPSIS...SUGDEN SHORT TERM...SUGDEN LONG TERM....BURGERT AVIATION...SUGDEN FIRE WEATHER...SUGDEN CLIMATE...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
333 AM CDT SUN APR 1 2012 ...UPDATED SYNOPSIS/SHORT TERM/FIRE WEATHER/CLIMATE DISCUSSIONS... .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 333 AM CDT SUN APR 1 2012 .SYNOPSIS... ISSUED AT 333 AM CDT SUN APR 1 2012 THE APRIL 1 2012 00Z 300 HPA SYNOPTIC MAP SHOWED A LARGE ANTICYCLONIC CURVED JET EXTENDING ACROSS THE WESTERN UNITED STATES AND INTO THE CANADIAN PRAIRIE PROVINCES. A JET STREAK OF AROUND 130-140 KT WAS OBSERVED FROM KREV TO KBOI. AT 500 HPA, AN AMPLIFIED TROUGH ASSOCIATED WITH THE JET STREAK WAS LOCATED ACROSS THE PACIFIC NORTHWEST AND INTO NORTHERN CALIFORNIA. CONSIDERABLE COLD AIR ADVECTION WITH 500 HPA DELTA TEMPERATURES AROUND 10 DEG C WAS OBSERVED ACROSS THE PACIFIC NORTHWEST ALONG WITH SIGNIFICANT HEIGHT FALLS. MORE LOCALLY AND AT LOWER LEVELS, A WARM AND DRY PLUME AT 700 AND 850 HPA PREVAILED ACROSS THE HIGH PLAINS. AT THE SFC, A LOW PRESSURE CENTER WAS LOCATED ACROSS EASTERN COLORADO. A DRYLINE ASSOCIATED WITH THIS FEATURE WAS LOCATED ACROSS THE SOUTHERN HIGH PLAINS AS WELL. THIS MORNING: AS WITH LAST NIGHT, HAVE FOLLOWED HRRR GUIDANCE IN CONCERNING THE POTENTIAL FOR PATCHY FOG FORMATION THIS MORNING. THIS MODEL HAS BEEN TRENDING WELL AS SITES AROUND KANSAS AND OKLAHOMA HAVE BEEN REPORTING BR THROUGH THE OVERNIGHT HOURS. I DID, HOWEVER, TAKE A MORE CONSERVATIVE APPROACH AS FAR AS DENSE FOG IS CONCERNED AND STUCK WITH PATCHY RATHER THAN +FG AS THE WINDS HAVE REMAINED ELEVATED THIS MORNING, WHICH COULD LIMIT THE OVERALL FOG INTENSITY. RECENT LAMP GUIDANCE AND RUC VIS OUTPUT SEEMS TO AGREE WITH THIS APPROACH AS WELL. FOG CONCERNS WILL BE OVER BY MID MORNING IF NOT SOONER. TODAY: UNPLEASANTLY WARM TEMPERATURES ARE EXPECTED TODAY. I SAY UNPLEASANT BECAUSE IT WILL FEEL DOWN RIGHT "HOT" RELATIVE TO THE BEGINNING OF APRIL. I DID TAKE THE COOLER SIDE OF MOS GUIDANCE AS BOISE VERIFICATION STILL SHOWS A WARM BIAS FROM THE MODELS. ONE REASON AS SUGGESTED FROM YESTERDAYS DAY SHIFT IS THAT EVAPOTRANSPIRATION FROM A RECENT HEAVY RAINFALL EVENT IS SLOWING DOWN HEAT FLUXES. IN ADDITION, DEWPOINTS ARE RUNNING AROUND 60 DEG F THIS MORNING SO THE ATMOSPHERE DOES HAVE SOME MOISTURE WHICH WILL RETARD SENSIBLE HEATING. THESE DEWPOINTS WILL LOWER AS THE DRYLINE WILL MIX EAST THROUGH THE AFTERNOON. CONVECTION IS NOT EXPECTED ALONG THE DRYLINE AS UPPER LEVEL RIDGING CONTINUES AND SUBSIDE PREVAILS AHEAD OF A WESTERN TROUGH. SOME RECORDS COULD BE IN JEOPARDY TODAY WHICH HAS BEEN HIGHLIGHTED IN THE CLIMATE SECTION BELOW. ANOTHER CONCERN FOR TODAY IS WINDS. THE 00Z GFS IS STRONGER WITH 850 HPA WINDS COMPARED TO THE 00Z NAM. THE ATMOSPHERE WILL BECOME WELL MIXED THIS AFTERNOON IN THE WAKE OF THE DRYLINE, HOWEVER WINDS PER THE MESOSCALE MODELS ARE NOT THAT IMPRESSIVE AND USING MIX DOWN TECHNIQUES SHOWS THAT A MARGINAL OR SUB MARGINAL WIND ADVISORY SPEEDS ARE POSSIBLE ACROSS THE WESTERN AND CENTRAL SECTIONS OF THE CWFA TODAY. AS A RESULT, DID NOT ISSUE A WIND ADVISORY FOR TODAY. LASTLY, CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY WHICH IS ADDRESSED BELOW IN THE FIRE WEATHER SECTION. TONIGHT: WINDS WILL GRADUALLY VEER OVERNIGHT AHEAD OF AN APPROACHING SIGNIFICANT COLD FRONT. TEMPERATURES WILL BE MILD AND GENERALLY IN THE 40S DEG F WEST TO 50S DEG F EAST. NO PRECIPITATION IS EXPECTED DURING THIS TIME FRAME AS DYNAMICS WILL NOT ARRIVE UNTIL AS DESCRIBED IN THE LONG TERM SECTION. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 PM CDT SAT MAR 31 2012 ON MONDAY AN ELONGATED UPPER LEVEL TROUGH WILL BEGIN TO GET CUTOFF AT THE BASE JUST SOUTH OF THE FOUR CORNERS REGION AND MOVE INTO NORTHEASTERN NEW MEXICO. THIS WILL ALLOW A COLD FRONT TO SURGE INTO SOUTHWESTERN KANSAS ON MONDAY MORNING, THEN ACROSS MUCH OF SOUTH CENTRAL KANSAS BY EVENING TO NEAR MEDICINE LODGE. PREFER THE FASTER FRONTAL MOVEMENT OF THE NAM/GFS THAN THE ECMWF BECAUSE OF THE STRONGER NORTHERN BRANCH WAVE MOVING ACROSS THE DAKOTAS. A FEW THUNDERSTORMS WILL BE POSSIBLE IN THE AFTERNOON ALONG AND AHEAD OF THE COLD FRONT, MAINLY EAST OF LINE FROM COLDWATER TO SAINT JOHN. IF STORMS FORM A FEW COULD HAVE SOME SMALL HAIL. HOWEVER IF THE FRONT DELAYS THE STORMS COULD BE STRONGER NEAR A COLD FRONT AND DRYLINE INTERSECTION. AHEAD OF THE COLD FRONT LOWS WILL BE MILD AND INTO THE UPPER 40S NORTHEAST AND MID 50S SOUTHEAST FA. HIGH TEMPERATURES ON MONDAY WILL RANGE FROM THE 60S NORTHWEST TO THE LOW TO MID 80S SOUTHEAST FA. FOR TUESDAY THE UPPER LOW MOVES NORTHEASTWARD SLOWLY INTO THE TEXAS PANHANDLE AND PARTS OF FAR SOUTHWESTERN KANSAS. THE GEM AND THE ECMWF ARE A BIT FASTER WITH THE UPPER LOW THAN THE GFS. RAIN SHOWERS AND A FEW THUNDERSTORMS WILL RAPIDLY SPREAD NORTH AHEAD OF THE UPPER LOW INTO SOUTHWEST AND SOUTH CENTRAL KANSAS. THE BEST CHANCES WILL OCCUR AFTER MIDNIGHT. A CHANCE FOR THUNDERSTORMS WITH SOME ELEVATED CAPE WILL BE MAINLY EAST OF A LINE FROM LARNED TO ASHLAND. SEVERE WEATHER IS NOT EXPECTED. LOWS ON TUESDAY MORNING LOOK TO BE IN THE UPPER 30S WEST TO NEAR 50 EAST FA. HIGHS ON TUESDAY WILL RANGE FROM NEAR 50 IN THE FAR WEST TO THE LOW TO MID 60S FAR EAST FA. ON WEDNESDAY THE UPPER LOW CONTINUES TO MOVE NORTHEAST AND INTO EASTERN KANSAS AND OKLAHOMA. LOWS IN MORNING WILL BE IN THE UPPER 30S FAR WEST TO THE MID AND UPPER 40S EAST. HIGH TEMPERATURES WILL RANGE FROM THE MID 60S WEST TO AROUND 60 NORTHEAST. RAIN CHANCES DIMINISH FROM WEST TO EAST WITH THE UPPER LOW. TOTAL RAINFALL COULD RANGE FROM ONE QUARTER TO OVER ONE HALF INCH WITH THE HIGHEST IN THE SOUTHEASTERN FA FROM LARNED TO ASHLAND. FOR THURSDAY THE UPPER LEVEL SHORTWAVE RIDGING WILL MOVE INTO THE PLAINS WITH A WARM UP BACK INTO THE 70S. ANOTHER UPPER LEVEL SHORTWAVE TROUGH WILL MOVE RAPIDLY NORTHEASTWARD ACROSS THE NORTHERN AND CENTRAL PLAINS FOR FRIDAY PUSHING ANOTHER COLD FRONT ACROSS KANSAS ON SATURDAY AS IT MOVES INTO THE NORTHERN HIGH PLAINS. LITTLE IF ANY RAINFALL IS EXPECTED. HIGHS ON FRIDAY LOOK TO BE IN THE MID TO UPPER 70S WITH SLIGHTLY COOLER TEMPS ON SATURDAY TO AROUND 70. OVERNIGHT LOWS WILL BE IN THE 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1201 AM CDT SUN APR 1 2012 TWO CONCERNS FOR THE 06Z TAFS. FOG AND WINDS. THE 01/02Z HRRR IS MOST AGGRESSIVE IN BRINGING DENSE FOG ACROSS SOUTH CENTRAL KANSAS BY MORNING. THIS MODEL WAS FAIRLY ACCURATE LAST NIGHT ALTHOUGH A LITTLE TOO LOW ON VIS. THE RUC ALSO SHOWS LOWERED VIS GENERALLY IN THE SAME AREA. DON`T HAVE ENOUGH CONFIDENCE FOR LIFR CIGS BUT HAVE LOWERED CIGS FROM VFR TO MVFR TO START OUT ON THE CONSERVATIVE SIDE SINCE THE HRRR OVERDID IT LAST NIGHT. SECOND CONCERN IS WINDS. HAVE INCREASED SW WINDS 20-25 KT WITH GUSTS TO 30-35 KT AS THE LEE SFC TROUGH STRENGTHENS TOMORROW AFTERNOON. && .FIRE WEATHER... ISSUED AT 333 AM CDT SUN APR 1 2012 AFTER COORDINATION WITH SURROUNDING WFO`S, HAVE CONTINUED THE RFW TODAY AND ADDED CLARK COUNTY IN. THE EASTERN COLUMN OF COUNTIES IS A BIT MARGINAL AS RH`S WILL BE IN THE 15 TO 17 PERCENT RANGE. DECIDED TO ERROR ON THE SIDE OF CAUTION AND KEEP THE COUNTIES IN THE WARNING AS TODAYS HIGHS WILL BE VERY WARM AND THE MODELS TYPICALLY UNDER FORECAST DEWPOINTS IN ASSOCIATION WITH A MIXING DRYLINE AND ADIABATIC COMPRESSIONAL WARMING. && .CLIMATE... ISSUED AT 333 AM CDT SUN APR 1 2012 A VERY ANOMALOUS DAY OF EXTREMELY WARM TEMPERATURES IS EXPECTED TODAY. POSITIVE TEMPERATURE DEVIATIONS OF 20 TO 30 DEGREES IS LIKELY ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS. SOME RECORDS COULD BE BROKEN TODAY. CLIMATE RECORDS IS AS FOLLOWS: RECORD (YEAR)..........................FORECAST HIGH FOR TODAY DODGE CITY: 88 (1940, 1964)............89 MEDICINE LODGE: 93 (1946)..............86 GARDEN CITY: 87 (1964).................90 ELKHART 89 (1946)......................90 && .PRELIMINARY POINT TEMPS/POPS... DDC 89 52 74 41 / 0 10 10 60 GCK 90 50 69 40 / 0 10 10 50 EHA 90 49 66 38 / 0 10 20 50 LBL 90 50 71 40 / 0 10 20 50 HYS 88 54 72 41 / 0 10 10 50 P28 86 57 82 51 / 0 10 40 60 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR KSZ030-043>045-061>064-074>078-084>088. && $$ SYNOPSIS...SUGDEN SHORT TERM...SUGDEN LONG TERM....KRUSE AVIATION...SUGDEN FIRE WEATHER...SUGDEN CLIMATE...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
247 AM CDT SUN APR 1 2012 ...UPDATED LONG TERM DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 321 PM CDT SAT MAR 31 2012 THE PRIMARY FORECAST CHALLENGES IN THE SHORT TERM ARE THE FOLLOWING: 1) EVALUATING THE PROBABILITY FOR PATCHY DENSE FOG SUNDAY MORNING IN THE RICH BUT SHALLOW LOW LEVEL MOISTURE FIELD IN SOUTH CENTRAL KANSAS; 2) DETERMINING HOW FAR EAST THE DRYLINE WILL PROGRESS ON SUNDAY AS CYCLOGENESIS OCCURS IN EASTERN COLORADO; 3) DETERMINING THE AREA WHERE RED FLAG CONDITIONS WILL BE MET SUNDAY AFTERNOON; AND 4) ANTICIPATING TEMPERATURES IN THE ANOMALOUSLY WARM AIR SUNDAY AFTERNOON. A MADDEN-JULIAN OSCILLATION CONTINUES TO MOVE DOWN THE SOUTH PACIFIC CONVERGENCE ZONE FROM NORTH OF AUSTRALIA INTO THE TROPICAL SOUTH PACIFIC. A TROPICAL CYCLONE WAS IN PROGRESS EAST OF VIET NAM ON THE TRAILING EDGE OF THE MADDEN-JULIAN OSCILLATION. THE GLOBAL MODELS ARE IN GOOD AGREEMENT IN MOVING THE MADDEN-JULIAN OSCILLATION INTO PHASE 8 OF THE WHEELER-HENDON PHASE SPACE DIAGRAM BY AROUND EASTER, AND THIS PATTERN FAVORS ANTICYCLONIC FLOW ALOFT IN THE NORTHERN ROCKIES. THE MODEL SOLUTIONS OF A SPLIT FLOW WITH AN ANTICYCLONICALLY BREAKING UPPER LEVEL CYCLONE WALLOWING INTO THE CENTRAL PART OF THE COUNTRY FOLLOWED BY A BUILDING RIDGE BACK INTO THE NORTHERN ROCKIES NEXT WEEKEND SEEM VERY REASONABLE. IN THE SHORTER TERM, THE MODELS ARE IN GOOD AGREEMENT WITH DIGGING THE SOUTHERN PART OF THE STRONG TROUGH INTO ARIZONA BY SUNDAY EVENING WHILE THE NORTHERN PORTION OF THE TROUGH LIFTS OUT INTO SASKATCHEWAN IN THE NORTHERN BRANCH OF THE WESTERLIES. THERE ALWAYS IS UNCERTAINTY ON HOW CLOSED UPPER LEVEL CYCLONES WILL EVOLVE WITH TIME, BUT THE SLOWER GFS SOLUTION PROBABLY IS FAIRLY GOOD. THE GFS LARGELY WAS USED FOR GRID MODIFICATIONS THROUGH SUNDAY. PRESSURES ALREADY ARE FALLING IN THE LEE OF THE ROCKIES THIS AFTERNOON, AND THE TROUGH WILL CONTINUE TO DEEPEN TONIGHT. LOW LEVEL MOISTURE WILL SLOSH BACK WESTWARD TONIGHT AS THE LOW LEVEL WINDS BACK, BUT THE MOISTURE FIELD WILL BE RATHER SHALLOW ACROSS MOST OF WESTERN KANSAS. BY SUNRISE, VEERING LOW LEVEL FLOW WILL BEGIN TO ERODE THE MOISTURE IN FAR WESTERN KANSAS, AND THE DRYLINE GRADUALLY WILL MIX EASTWARD DURING THE DAY. THE RICHEST LOW LEVEL MOISTURE WILL BE IN SOUTH CENTRAL KANSAS TONIGHT WITH DRY AIR ABOVE THE MOIST LAYER. LOW LEVEL WINDS WILL BE RELATIVELY LIGHT IN SOUTH CENTRAL KANSAS, AND THE MOISTURE MAY BE DEEP ENOUGH THAT THE HYDROLAPSE WILL FAVOR PATCHY FOG FORMATION BY SUNRISE. WHATEVER FOG DOES FORM WILL BURN OFF QUICKLY AS WINDS INCREASE DURING THE EARLY MORNING HOURS. PRESSURES WILL CONTINUE TO FALL IN THE LEE OF THE ROCKIES SUNDAY AS CYCLOGENESIS OCCURS IN NORTHEASTERN COLORADO. THE SHALLOW MOISTURE WILL MIX OUT AT LEAST AS FAR EAST AS DODGE CITY BY MID AFTERNOON, AND A VERY DEEPLY MIXED BOUNDARY LAYER WILL EVOLVE DURING THE DAY. H8 WINDS WILL INCREASE TO 30-35 KNOTS BY LATE MORNING, SO SURFACE WINDS IN THE 20 TO 25 KNOT RANGE WITH GUSTS INTO THE 30-35 KNOT RANGE SEEM REASONABLE. H8 DEWPOINTS WILL DROP TO NEAR -10C IN FAR WESTERN KANSAS WITH VALUES NEAR 0C AS FAR EAST AS DODGE CITY. WITH H8 TEMPERATURES ABOVE 25C IN THE DRY AIR, SURFACE TEMPERATURES WILL APPROACH RECORDS IN A FEW LOCATIONS. EVAPOTRANSPIRATION FROM VEGETATION MAY SHAVE TWO OR THREE DEGREES OFF MAXIMUM TEMPERATURES, BUT HIGHS NEAR 90 DEGREES ARE LIKELY. WINDS MAY APPROACH ADVISORY CRITERIA BY MID AFTERNOON AND WILL HAVE TO BE MONITORED FOR POSSIBLE HEADLINES BY SUBSEQUENT SHIFTS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 243 AM CDT SUN APR 1 2012 MODELS THIS MORNING REMAIN IN GOOD AGREEMENT WITH QUICKLY MOVING AN UPPER LEVEL TROUGH WHICH WAS LOCATED JUST OFF THE WEST COAST OF CALIFORNIA TO NEAR THE FOUR CORNERS REGION BY 06Z MONDAY. THIS UPPER LEVEL SYSTEM THEN DEEPENS AS IT CROSSES NEW MEXICO DURING THE DAY ON MONDAY. BY 00Z TUESDAY THE GFS, ECMWF, AND NAM ALL PLACE THIS UPPER LEVEL LOW NEAR EAST CENTRAL NEW MEXICO. AHEAD OF THIS DEEPENING UPPER LEVEL SYSTEM A COLD FRONT WILL BE MOVING SOUTH ACROSS WESTERN KANSAS DURING THE DAY AND BASED ON THE GFS AND NAM THIS FRONTAL BOUNDARY WILL BE LOCATED NEAR THE OKLAHOMA BORDER AND SOUTH CENTRAL KANSAS BY 00Z TUESDAY. BOTH MODELS THIS MORNING ARE IN GOOD AGREEMENT WITH CONVECTION DEVELOPING ALONG THIS COLD FRONT LATE DAY DESPITE THE DIFFERENCES IN THE LOCATION OF THIS FRONT MONDAY EVENING. THE CONVECTION LATE DAY DOES APPEAR REASONABLE GIVEN THE MOISTURE RETURN FORECAST AHEAD OF THIS FRONT, IMPROVING LOW LEVEL FORCING AND LATE DAY INSTABILITY. AS A RESULT WILL CONTINUE TO FAVOR KEEPING A MENTION OF LATE DAY STORMS ACROSS SOUTH CENTRAL KANSAS AFTER 21Z. DECENT MID LEVEL INSTABILITY AT 00Z TUESDAY AND CAPES ARE FORECAST TO BE AT OR ABOVE 2000 J/KG. MARGINAL SHEAR HOWEVER IS EXPECTED WITH 0-6KM SHEAR AT OR BELOW 30KTS. STILL GIVEN SOME LATE DAY HEATING AND IMPROVING FORCING ALONG THIS BOUNDARY DO THINK A FEW STORMS THAT DO DEVELOP ALONG THIS FRONT LATE DAY MAY BECOME SEVERE WITH HAIL UP TO QUARTER SIZE BEING THE MAIN HAZARD. NORTH/NORTHWEST OF THIS COLD FRONT LATE MONDAY GUSTY NORTHERLY WINDS ARE EXPECTED TO INCREASE INTO THE 25 TO 35 MPH RANGE AS AN AREA OF LOW PRESSURE AT THE SURFACE DEEPENS ALONG THIS COLD FRONT ACROSS THE PANHANDLE OF TEXAS. THIS WILL BEGIN TO USHER IN SOME COOLER AIR LATE IN THE DAY SO TEMPERATURES BEHIND THIS COLD FRONT ARE EXPECTED TO STRUGGLE INTO THE UPPER 60S TO LOWER 70S. AHEAD OF THIS FRONT LOWER 80S STILL APPEAR LIKELY. THE CHANCES FOR PRECIPITATION THEN SPREADS NORTHWARD ACROSS ALL OF WESTERN AND MUCH OF NORTH CENTRAL KANSAS MONDAY NIGHT AS THE UPPER LEVEL LOW BEGINS TO LOWLY MOVE EAST INTO THE PANHANDLE OF TEXAS AND WARM AIR ADVECTION AND MOISTURE IMPROVES ACROSS WESTERN KANSAS DURING THE OVERNIGHT HOURS MONDAY NIGHT. FROM TUESDAY THROUGH EARLY WEDNESDAY A SERIES OF UPPER LEVEL DISTURBANCES WILL ROTATE AROUND THIS UPPER LOW AS IT MOVES FROM THE PANHANDLE OF TEXAS INTO SOUTH CENTRAL KANSAS. MOISTURE AND LIFT (WARM AIR ADVECTION, ISENTROPIC LIFT, 850-700MB FRONTOGENESIS) CONTINUES SO HAVE THEREFORE RAISE PRECIPITATION CHANCES ACROSS THE ENTIRE AREA. BY LATE WEDNESDAY AN UPPER LEVEL SHORT WAVE RIDGE WILL BEGIN TO BUILD INTO THE ROCKIES AS THE UPPER LOW CONTINUES TO TRACK EASTWARD ACROSS EASTERN KANSAS. SKIES ARE EXPECTED TO CLEAR FROM WEST TO EAST AS THE PRECIPITATION ENDS. TEMPERATURES WEDNESDAY NIGHT HAS THE POTENTIAL TO FALL BACK TO NEAR FREEZING IF SKIES CLEAR QUICK ENOUGH AND WIND GO LIGHT BUT GIVEN THE TIMING ISSUES OF THE UPPER LOW HAVE DECIDED TO STAY CLOSE TO LATEST ALLBLEND. ON THURSDAY AND FRIDAY A WARMING TREND CAN BE EXPECTED ACROSS WESTERN KANSAS AS THE UPPER LEVEL RIDGE AXIS BUILDS EAST OUT INTO THE PLAINS AND WESTERLY DOWN SLOPE FLOW IMPROVES && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1201 AM CDT SUN APR 1 2012 TWO CONCERNS FOR THE 06Z TAFS. FOG AND WINDS. THE 01/02Z HRRR IS MOST AGGRESSIVE IN BRINGING DENSE FOG ACROSS SOUTH CENTRAL KANSAS BY MORNING. THIS MODEL WAS FAIRLY ACCURATE LAST NIGHT ALTHOUGH A LITTLE TOO LOW ON VIS. THE RUC ALSO SHOWS LOWERED VIS GENERALLY IN THE SAME AREA. DON`T HAVE ENOUGH CONFIDENCE FOR LIFR CIGS BUT HAVE LOWERED CIGS FROM VFR TO MVFR TO START OUT ON THE CONSERVATIVE SIDE SINCE THE HRRR OVERDID IT LAST NIGHT. SECOND CONCERN IS WINDS. HAVE INCREASED SW WINDS 20-25 KT WITH GUSTS TO 30-35 KT AS THE LEE SFC TROUGH STRENGTHENS TOMORROW AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... DDC 89 52 74 41 / 0 10 10 60 GCK 90 50 69 40 / 0 10 10 50 EHA 90 49 66 38 / 0 10 20 50 LBL 90 50 71 40 / 0 10 20 50 HYS 88 54 72 41 / 0 10 10 50 P28 86 57 82 51 / 0 10 40 60 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR KSZ030-043>045-061>064-074>078-084>088. && $$ UPDATE...RUTHI SYNOPSIS...RUTHI SHORT TERM...RUTHI LONG TERM....BURGERT AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1208 AM CDT SUN APR 1 2012 ...UPDATE TO AVIATION FOR 06Z TAFS... .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 321 PM CDT SAT MAR 31 2012 THE PRIMARY FORECAST CHALLENGES IN THE SHORT TERM ARE THE FOLLOWING: 1) EVALUATING THE PROBABILITY FOR PATCHY DENSE FOG SUNDAY MORNING IN THE RICH BUT SHALLOW LOW LEVEL MOISTURE FIELD IN SOUTH CENTRAL KANSAS; 2) DETERMINING HOW FAR EAST THE DRYLINE WILL PROGRESS ON SUNDAY AS CYCLOGENESIS OCCURS IN EASTERN COLORADO; 3) DETERMINING THE AREA WHERE RED FLAG CONDITIONS WILL BE MET SUNDAY AFTERNOON; AND 4) ANTICIPATING TEMPERATURES IN THE ANOMALOUSLY WARM AIR SUNDAY AFTERNOON. A MADDEN-JULIAN OSCILLATION CONTINUES TO MOVE DOWN THE SOUTH PACIFIC CONVERGENCE ZONE FROM NORTH OF AUSTRALIA INTO THE TROPICAL SOUTH PACIFIC. A TROPICAL CYCLONE WAS IN PROGRESS EAST OF VIET NAM ON THE TRAILING EDGE OF THE MADDEN-JULIAN OSCILLATION. THE GLOBAL MODELS ARE IN GOOD AGREEMENT IN MOVING THE MADDEN-JULIAN OSCILLATION INTO PHASE 8 OF THE WHEELER-HENDON PHASE SPACE DIAGRAM BY AROUND EASTER, AND THIS PATTERN FAVORS ANTICYCLONIC FLOW ALOFT IN THE NORTHERN ROCKIES. THE MODEL SOLUTIONS OF A SPLIT FLOW WITH AN ANTICYCLONICALLY BREAKING UPPER LEVEL CYCLONE WALLOWING INTO THE CENTRAL PART OF THE COUNTRY FOLLOWED BY A BUILDING RIDGE BACK INTO THE NORTHERN ROCKIES NEXT WEEKEND SEEM VERY REASONABLE. IN THE SHORTER TERM, THE MODELS ARE IN GOOD AGREEMENT WITH DIGGING THE SOUTHERN PART OF THE STRONG TROUGH INTO ARIZONA BY SUNDAY EVENING WHILE THE NORTHERN PORTION OF THE TROUGH LIFTS OUT INTO SASKATCHEWAN IN THE NORTHERN BRANCH OF THE WESTERLIES. THERE ALWAYS IS UNCERTAINTY ON HOW CLOSED UPPER LEVEL CYCLONES WILL EVOLVE WITH TIME, BUT THE SLOWER GFS SOLUTION PROBABLY IS FAIRLY GOOD. THE GFS LARGELY WAS USED FOR GRID MODIFICATIONS THROUGH SUNDAY. PRESSURES ALREADY ARE FALLING IN THE LEE OF THE ROCKIES THIS AFTERNOON, AND THE TROUGH WILL CONTINUE TO DEEPEN TONIGHT. LOW LEVEL MOISTURE WILL SLOSH BACK WESTWARD TONIGHT AS THE LOW LEVEL WINDS BACK, BUT THE MOISTURE FIELD WILL BE RATHER SHALLOW ACROSS MOST OF WESTERN KANSAS. BY SUNRISE, VEERING LOW LEVEL FLOW WILL BEGIN TO ERODE THE MOISTURE IN FAR WESTERN KANSAS, AND THE DRYLINE GRADUALLY WILL MIX EASTWARD DURING THE DAY. THE RICHEST LOW LEVEL MOISTURE WILL BE IN SOUTH CENTRAL KANSAS TONIGHT WITH DRY AIR ABOVE THE MOIST LAYER. LOW LEVEL WINDS WILL BE RELATIVELY LIGHT IN SOUTH CENTRAL KANSAS, AND THE MOISTURE MAY BE DEEP ENOUGH THAT THE HYDROLAPSE WILL FAVOR PATCHY FOG FORMATION BY SUNRISE. WHATEVER FOG DOES FORM WILL BURN OFF QUICKLY AS WINDS INCREASE DURING THE EARLY MORNING HOURS. PRESSURES WILL CONTINUE TO FALL IN THE LEE OF THE ROCKIES SUNDAY AS CYCLOGENESIS OCCURS IN NORTHEASTERN COLORADO. THE SHALLOW MOISTURE WILL MIX OUT AT LEAST AS FAR EAST AS DODGE CITY BY MID AFTERNOON, AND A VERY DEEPLY MIXED BOUNDARY LAYER WILL EVOLVE DURING THE DAY. H8 WINDS WILL INCREASE TO 30-35 KNOTS BY LATE MORNING, SO SURFACE WINDS IN THE 20 TO 25 KNOT RANGE WITH GUSTS INTO THE 30-35 KNOT RANGE SEEM REASONABLE. H8 DEWPOINTS WILL DROP TO NEAR -10C IN FAR WESTERN KANSAS WITH VALUES NEAR 0C AS FAR EAST AS DODGE CITY. WITH H8 TEMPERATURES ABOVE 25C IN THE DRY AIR, SURFACE TEMPERATURES WILL APPROACH RECORDS IN A FEW LOCATIONS. EVAPOTRANSPIRATION FROM VEGETATION MAY SHAVE TWO OR THREE DEGREES OFF MAXIMUM TEMPERATURES, BUT HIGHS NEAR 90 DEGREES ARE LIKELY. WINDS MAY APPROACH ADVISORY CRITERIA BY MID AFTERNOON AND WILL HAVE TO BE MONITORED FOR POSSIBLE HEADLINES BY SUBSEQUENT SHIFTS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 PM CDT SAT MAR 31 2012 ON MONDAY AN ELONGATED UPPER LEVEL TROUGH WILL BEGIN TO GET CUTOFF AT THE BASE JUST SOUTH OF THE FOUR CORNERS REGION AND MOVE INTO NORTHEASTERN NEW MEXICO. THIS WILL ALLOW A COLD FRONT TO SURGE INTO SOUTHWESTERN KANSAS ON MONDAY MORNING, THEN ACROSS MUCH OF SOUTH CENTRAL KANSAS BY EVENING TO NEAR MEDICINE LODGE. PREFER THE FASTER FRONTAL MOVEMENT OF THE NAM/GFS THAN THE ECMWF BECAUSE OF THE STRONGER NORTHERN BRANCH WAVE MOVING ACROSS THE DAKOTAS. A FEW THUNDERSTORMS WILL BE POSSIBLE IN THE AFTERNOON ALONG AND AHEAD OF THE COLD FRONT, MAINLY EAST OF LINE FROM COLDWATER TO SAINT JOHN. IF STORMS FORM A FEW COULD HAVE SOME SMALL HAIL. HOWEVER IF THE FRONT DELAYS THE STORMS COULD BE STRONGER NEAR A COLD FRONT AND DRYLINE INTERSECTION. AHEAD OF THE COLD FRONT LOWS WILL BE MILD AND INTO THE UPPER 40S NORTHEAST AND MID 50S SOUTHEAST FA. HIGH TEMPERATURES ON MONDAY WILL RANGE FROM THE 60S NORTHWEST TO THE LOW TO MID 80S SOUTHEAST FA. FOR TUESDAY THE UPPER LOW MOVES NORTHEASTWARD SLOWLY INTO THE TEXAS PANHANDLE AND PARTS OF FAR SOUTHWESTERN KANSAS. THE GEM AND THE ECMWF ARE A BIT FASTER WITH THE UPPER LOW THAN THE GFS. RAIN SHOWERS AND A FEW THUNDERSTORMS WILL RAPIDLY SPREAD NORTH AHEAD OF THE UPPER LOW INTO SOUTHWEST AND SOUTH CENTRAL KANSAS. THE BEST CHANCES WILL OCCUR AFTER MIDNIGHT. A CHANCE FOR THUNDERSTORMS WITH SOME ELEVATED CAPE WILL BE MAINLY EAST OF A LINE FROM LARNED TO ASHLAND. SEVERE WEATHER IS NOT EXPECTED. LOWS ON TUESDAY MORNING LOOK TO BE IN THE UPPER 30S WEST TO NEAR 50 EAST FA. HIGHS ON TUESDAY WILL RANGE FROM NEAR 50 IN THE FAR WEST TO THE LOW TO MID 60S FAR EAST FA. ON WEDNESDAY THE UPPER LOW CONTINUES TO MOVE NORTHEAST AND INTO EASTERN KANSAS AND OKLAHOMA. LOWS IN MORNING WILL BE IN THE UPPER 30S FAR WEST TO THE MID AND UPPER 40S EAST. HIGH TEMPERATURES WILL RANGE FROM THE MID 60S WEST TO AROUND 60 NORTHEAST. RAIN CHANCES DIMINISH FROM WEST TO EAST WITH THE UPPER LOW. TOTAL RAINFALL COULD RANGE FROM ONE QUARTER TO OVER ONE HALF INCH WITH THE HIGHEST IN THE SOUTHEASTERN FA FROM LARNED TO ASHLAND. FOR THURSDAY THE UPPER LEVEL SHORTWAVE RIDGING WILL MOVE INTO THE PLAINS WITH A WARM UP BACK INTO THE 70S. ANOTHER UPPER LEVEL SHORTWAVE TROUGH WILL MOVE RAPIDLY NORTHEASTWARD ACROSS THE NORTHERN AND CENTRAL PLAINS FOR FRIDAY PUSHING ANOTHER COLD FRONT ACROSS KANSAS ON SATURDAY AS IT MOVES INTO THE NORTHERN HIGH PLAINS. LITTLE IF ANY RAINFALL IS EXPECTED. HIGHS ON FRIDAY LOOK TO BE IN THE MID TO UPPER 70S WITH SLIGHTLY COOLER TEMPS ON SATURDAY TO AROUND 70. OVERNIGHT LOWS WILL BE IN THE 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1201 AM CDT SUN APR 1 2012 TWO CONCERNS FOR THE 06Z TAFS. FOG AND WINDS. THE 01/02Z HRRR IS MOST AGGRESSIVE IN BRINGING DENSE FOG ACROSS SOUTH CENTRAL KANSAS BY MORNING. THIS MODEL WAS FAIRLY ACCURATE LAST NIGHT ALTHOUGH A LITTLE TOO LOW ON VIS. THE RUC ALSO SHOWS LOWERED VIS GENERALLY IN THE SAME AREA. DON`T HAVE ENOUGH CONFIDENCE FOR LIFR CIGS BUT HAVE LOWERED CIGS FROM VFR TO MVFR TO START OUT ON THE CONSERVATIVE SIDE SINCE THE HRRR OVERDID IT LAST NIGHT. SECOND CONCERN IS WINDS. HAVE INCREASED SW WINDS 20-25 KT WITH GUSTS TO 30-35 KT AS THE LEE SFC TROUGH STRENGTHENS TOMORROW AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 74 43 57 / 0 10 50 50 GCK 49 69 41 55 / 0 10 50 50 EHA 50 66 37 50 / 0 20 50 40 LBL 49 71 40 55 / 0 20 50 50 HYS 52 72 44 59 / 0 10 40 50 P28 57 82 49 63 / 0 30 50 50 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR KSZ030-043>045-061>064-074>078-084>087. && $$ UPDATE...RUTHI SYNOPSIS...RUTHI SHORT TERM...RUTHI LONG TERM....KRUSE AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS WICHITA KS
1135 PM CDT SAT MAR 31 2012 .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN CONCERN REMAINS POTENTIAL FOR LOW STRATUS. LEE TROUGH WILL ALLOW LIGHT SOUTH-SOUTHEASTERLY WINDS TO CONTINUE OVERNIGHT WITH INCREASING BOUNDARY LAYER MOISTURE. THIS SHOULD RESULT IN LIFR-IFR STRATUS DEVELOPMENT OVER MUCH OF THE AREA DURING THE EARLY AM HOURS SUNDAY. THIS IS SUPPORTED IN THE NAM...GFS...RUC...AND 3KM HRRR MODELS. FORECAST CONFIDENCE IS ABOVE AVERAGE GIVEN THE LOW STRATUS OCCURRENCE IN CENTRAL/SOUTHWEST OK AND NORTH CENTRAL TEXAS SATURDAY MORNING. THE STRATUS LOOKS TO BURN OFF TOWARD MIDDAY SUNDAY. BETTER MIXING AND NEAR FULL SUNSHINE SUNDAY AFTERNOON SHOULD RESULT IN SOUTHERLY GUSTS ~25 KT MOST OF THE AREA. JMC && PREV DISCUSSION... /ISSUED 243 PM CDT SAT MAR 31 2012/ DISCUSSION... FORECAST CHALLENGES...LOW CLOUD TRENDS TONIGHT/SUNDAY MORNING AND THEN PRECIP CHANCES/TRENDS EARLY NEXT WEEK. TONIGHT-MONDAY LITTLE CHANGE TO THE FORECAST TO CLOSE OUT THE WEEKEND...WITH THE UNSEASONABLE WARMTH CLOSING IN ON SOME RECORDS. FOR THIS EVENING...SOUTHEAST KANSAS WILL REMAIN ON EDGE OF WEAKER CAP WHERE MODERATE INSTABILITY WILL BE PRESENT PRIOR TO DARK. HOWEVER LACK OF FOCUS/TRIGGER SHOULD PRECLUDE CONVECTION SO WILL KEEP FORECAST DRY. SOME PATCHY LIGHT FOG WITH PERHAPS BETTER CHANCE FOR SOME LOW CLOUDS TO DEVELOP AROUND DAWN ACROSS SOUTHERN PORTIONS OF THE AREA WITH CLOUDS LINGERING INTO MIDDAY FOR AREAS EAST OF THE TURNPIKE. OTHERWISE...INCREASING SOUTHERLY FLOW/BETTER MIXING INTO SUNDAY AFTERNOON SHOULD RESULT IN MORE SUNSHINE...WIND AND VERY WARM MAXS ACROSS THE ENTIRE...GENERALLY IN THE 85 TO 90F RANGE. THE APPROACHING UPPER TROF WILL MOVE ACROSS THE SOUTHWEST CONUS SUNDAY NIGHT...BECOMING A CLOSED LOW AS IT MOVES ACROSS THE SOUTHERN ROCKIES DURING MONDAY. THE INHERITED FORECAST SUPPORTS THE LATEST MODEL CONSENSUS IN SLOWING THE SURFACE FRONTAL PASSAGE AND PRECIP/CONVECTIVE CHANCES TO LATER IN THE DAY ON MONDAY. THIS WILL RESULT IN ONE MORE DAY OF UNSEASONABLY WARM TEMPERATURES ESPECIALLY FOR LOCATIONS ALONG AND EAST OF THE TURNPIKE. TUESDAY-WEDNESDAY A LITTLE BETTER MODEL CONTINUITY EXISTS WITH THE MOVEMENT OF THE CLOSED UPPER LOW ACROSS MID-AMERICA INTO MID-WEEK...WITH BEST CHANCE FOR SHOWERS/STORMS ON TUESDAY AND WEDNESDAY. THURSDAY-SATURDAY A COUPLE DAYS OF DRY WEATHER EXPECTED IN THE WAKE OF THE DEPARTING UPPER LOW FOR THURSDAY AND FRIDAY. MEANWHILE UPPER TROUGHING WILL DEVELOP ACROSS THE WESTERN CONUS WITH A SIGNIFICANT SHORTWAVE LIFTING NORTHEAST ACROSS THE NORTHERN PLAINS BY SATURDAY. WHILE CONFIDENCE IS MODEST AT BEST...WILL SHOW SMALL PRECIP/CONVECTIVE CHANCES ALONG THE ASSOCIATED SURFACE FRONT FRIDAY NIGHT/SATURDAY. DARMOFAL AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU FAIRLY QUIET AVIATION FORECAST FOR MOST OF THE PERIOD. FEW-SCT DIURNAL CUMULUS THIS AFTERNOON AT KICT-KHUT-KCNU WILL BURN OFF BY 00-02Z. OTHERWISE...DIURNAL COOLING IN CONCERT WITH INCREASING BOUNDARY LAYER MOISTURE MAY PROMOTE A 3-5 HOUR PERIOD OF IFR/LIFR CIGS FROM 10/11Z THROUGH 14/15Z. THE NAM MODEL MAY BE OVER-MOISTENING THE BOUNDARY LAYER AS IT OFTEN DOES...HENCE CONFIDENCE IS LOW ON THIS OCCURRING...SO ONLY HINTED AT IT IN THE 18Z TAFS. ADK FIRE WEATHER... DESPITE UNSEASONBALY WARM TEMPERATURES AND INCREASING WINDS ON SUNDAY...THE GRASSLAND FIRE DANGER RISK IS EXPECTED TO BE ONLY SLIGHTLY ELEVATED DUE TO THE EARLY SPRING GREEN-UP. && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 60 87 61 84 / 0 0 0 20 HUTCHINSON 59 89 59 81 / 0 0 0 20 NEWTON 60 87 62 82 / 0 0 0 20 ELDORADO 60 87 63 85 / 0 0 0 20 WINFIELD-KWLD 61 88 63 86 / 0 0 0 20 RUSSELL 59 91 56 75 / 0 0 0 20 GREAT BEND 58 90 55 77 / 0 0 0 20 SALINA 61 90 60 81 / 0 0 0 20 MCPHERSON 60 89 60 81 / 0 0 0 20 COFFEYVILLE 62 88 66 88 / 0 10 10 10 CHANUTE 61 88 65 87 / 0 10 10 10 IOLA 61 88 65 87 / 0 10 10 10 PARSONS-KPPF 61 88 65 88 / 0 10 10 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DULUTH MN
342 AM CDT SUN APR 1 2012 LARGE AREA OF LOW CLOUDS/FOG HAS PERSISTED ACROSS MOST OF CWA OVERNIGHT AS APPROACHING FRNTL SYSTEM HAS STALLED/WEAKENED UNDERNEATH BUILDING MID LVL RIDGE. RUC13 SHOWS WINDS NORTH OF FRNTL BDRY AT 925 HAVE ALREADY SWITCHED TO NE INDICATING NOT MUCH PUSH TO GET THE BDRY THROUGH ANYTIME SOON. MSAS HAS PRESS RISES WEAKENING NORTH OF BDRY AS WELL. SFC T/TD SPREADS ARE NEAR ZERO OVER MOST OF NRN CWA WHERE MSTR HAS POOLED AHEAD OF DECAYING FRONT. LOCALLY DENSE FOG AT THIS TIME ACROSS NRN ITASCA/KOOCH/NRN STL COUNTIES. WILL ISSUE DFA FOR EARLY MORNING. TODAY..WIDESPREAD CLOUDS/FOG SHOULD GRADUALLY DIMINISH BY MIDDAY AS MID LVL RIDGE AXIS SHIFTS EAST TOWARDS LAKE SUPERIOR. BDRY LYR FLOW WILL INCREASE FROM SOUTHEAST DURING AFTN AND CEILINGS SHOULD LIFT. CLOUD FCST WILL BE CHALLENGING TODAY BUT HAVE LEANED WITH WRF ARW 4KM IDEA THAT CLEARING WILL ADVECT FROM MPX CWA BY LATE MORNING. HAVE USED A BIAS CORRECTED BLEND OF THE EC/ALLBLEND TO FCST MAX TEMPS. THIS ALSO RESPECTS THE BRISK ONSHORE COMPONENT THAT DEVELOPS THIS AFTN AS MESOSCALE WEDGE OF HIGH PRESSURE NOSES DOWN LAKE FROM ONTARIO. TONIGHT...CYCLOGENESIS OVER WRN HI PLAINS CREATES STRENGTHENING WARM ADVECTION PATTERN ACROSS NRN PLAINS. LLJ IS FCST TO PUSH INTO CWA WITH ELEVATED CONVECTION DEVELOPING AFTER 6Z. USING SREF CPTP AND EC/NAM CONVECTIVE FCSTS OF SHEAR/MUCAPE PUTS INCREASING LIKELIHOOD OF THUNDER INTO SWRN CWA MIDNIGHT...THEN ACROSS MOST OF CWA EXCEPT ERN ARROWHEAD BY 12Z. SREF 3HR CALIBRATED SVR VALUES QUITE LOW AT THIS TIME. TOMORROW...SFC LOW WILL TRACK INTO SWRN MN BY 0Z TUES. MAIN PUSH OF 85H MSTR TRANSPORT WILL BE FOCUSED ACROSS NRN TIER OF CWA WHERE LOCALLY HEAVY PRECIP IS POSSIBLE. EC/GEM/NAM IN MDT AGREEMENT THAT STRONG LOW LVL INVERTED TROUGH WILL BE AIDED BY APPROACHING UPPER TROF. MID LVL WARM ADVECTION MAY LIMIT MUCH PRECIP DEVELOPMENT OVER WISC ZONES..AND PERHAPS AS FAR NORTH AND WEST AS TWIN PORTS. LATER SHIFTS MAY NEED TO LOWER POPS EVEN FARTHER IN THIS AREA. .EXTENDED...MONDAY NIGHT THROUGH SATURDAY... AN UPPER LEVEL TROF WILL MOVE INTO THE FA MONDAY NIGHT PUSHING A SFC FRONT INTO NORTH CENTRAL WI BY 12Z TUESDAY. SHOWERS AND THUNDERSTORMS WILL OCCUR AHEAD OF THE TROF AND NEAR THE FRONT. THE TROF REACHES NE WI BY 00Z WEDNESDAY AND PUSHES THE FRONT WELL E OF THE AREA AND ENDS THE PCPN. TUESDAY NIGHT THROUGH FRIDAY WILL BE DOMINATED BY HIGH PRESSURE OVER THE GREAT LAKES. BY FRIDAY NIGHT...RETURN FLOW SETS UP AS THE SFC HIGH SLIPS FARTHER TO THE E. A STRONG LLJ AT 850MB WILL USHER IN WARM/MOIST AIR. ENOUGH DESTABILIZATION OCCURS TO MENTION SOME POPS OVER THE WESTERN TWO THIRDS OF THE FA. POPS ARE SPREAD OVER THE ENTIRE FA ON SATURDAY AS A CLOSED/STACKED UPPER LOW MEANDERS THROUGH THE NORTHERN PLAINS...SENDING PIECES OF ENERGY TOWARD THE FA. .AVIATION...06Z TAFS IFR OR LOW MVFR CEILINGS COVERED MOST OF THE NORTHLAND...WITH CLEAR SKIES FROM WALKER TO COOK TO CRANE LAKE AND POINTS NORTH AND WEST. SATELLITE DID SHOW THE STRATUS WAS MOVING BACK TOWARD THE WEST AND NORTH TOWARD WALKER. FOG WAS ALSO DEVELOPING...AND VSBYS SHOULD CONTINUE TO DROP OVERNIGHT. LOW LEVEL WINDS WILL BE VEERING TO EASTERLY LATE TONIGHT INTO SUNDAY...AND DENSE FOG MAY DEVELOP AROUND LAKE SUPERIOR AS AN ONSHORE FLOW DEVELOPS. NAM BUFR SOUNDINGS CONTINUE TO SHOW THE CEILINGS LIFTING QUICKLY ON SUNDAY...BUT WE HAVE LOW CONFIDENCE IN THAT OCCURRING GIVEN THE EASTERLY LOW LEVEL FLOW. MOISTURE/WARM AIR ADVECTION WILL BE INCREASING SUNDAY NIGHT...WITH THE STABILITY DROPPING. THE MODELS DO SHOW SHOWERS/STORMS DEVELOPING OVER PARTS OF THE NORTHLAND BY LATE EVENING. SOME OF THE STORMS COULD BE QUITE STRONG. .POINT TEMPS/POPS... DLH 55 41 54 38 / 10 30 40 50 INL 63 40 53 33 / 10 50 60 40 BRD 67 50 64 38 / 10 40 50 40 HYR 67 45 64 39 / 10 30 30 50 ASX 58 43 58 38 / 10 30 30 50 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ010>012- 018-019-021-025-026. WI...NONE. LS...NONE. && $$ SHORT TERM...CANNON LONG TERM....GSF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1201 AM CDT SUN APR 1 2012 .UPDATE... UPDATED FOR THE 06Z AVIATION DISCUSSION BELOW. && .DISCUSSION... CONSIDERABLE CLOUDINESS CONTINUES TO PLAGUE MUCH OF THE FA AT MID AFTERNOON. ONLY THE FAR WESTERN COUNTIES HAVE NEAR FULL SUN. SOME THINNING APPEARS TO BE OCCURRING OVER WEST CENTRAL WI. THE HRRR IS TRYING TO SHOW CLEARING WORKING INTO FAR EASTERN MN AND WEST CENTRAL WI BY THIS EVENING. HOWEVER...CLEARING OR NOT...THE PRESSURE GRADIENT WILL WEAKEN TONIGHT WITH SATURATION DEVELOPING DURING THE OVERNIGHT HOURS. THIS WILL LIKELY TO LEAD FOG AND MORE STRATUS REFORMING. NAM BUFKIT HYDROLAPSE SHOWS A NICE INCREASE JUST ABOUT EVERYWHERE TONIGHT DURING THE LATE NIGHT HOURS. INDICATED AREAS OF FOG IN THE FORECAST...BUT DENSE FOG IS NOT OUT OF THE QUESTION SUNDAY MORNING. IN ADDITION...A WEAK SHORT WAVE IS PASSING BY EARLY THIS EVENING. SEVERAL MODEL SOLUTIONS STILL TRY TO DEVELOP SOME SHOWERS OVER CENTRAL MN AND PASS THEM ACROSS THE TWIN CITIES AND WEST CENTRAL WI. CONFIDENCE IS NOT HIGH AND HAVE KEPT THE FORECAST DRY BUT THE DIFFERENTIAL HEATING OCCURRING TO OUR WEST NOW IS A CONCERN. MUCH BETTER INSTABILITY IS DEVELOPING OVER WESTERN IA ATTM AND THE LOW LEVEL MOISTURE TRANSPORT INCREASES EARLY THIS EVENING BETWEEN KDSM AND KMKE. SO SOME STORMS ARE POSSIBLE JUST TO OUR SOUTH OF OUR FA THIS EVENING. SUNDAY WILL BE THE WARMEST DAY OF THE NEXT SEVEN FOR MANY AREAS. MUCH WILL DEPEND ON THE AMOUNT OF STRATUS AND FOG IN THE MORNING...BUT WEST CENTRAL THROUGH SOUTH CENTRAL MN HAVE A REALLY GOOD CHANCE OF SEEING HIGHS REACH WELL INTO THE 80S. READINGS IN THE 80S ARE OCCURRING RIGHT NOW TO THE WEST AND SOUTH OF KFSD WITH H85 TEMPERATURES OF +16 TO +18 DEGREES C. SOUTHWEST AREAS OF MN WILL BE SOME 2 TO 3 DEGREES C ABOVE THIS SUNDAY AFTERNOON. A HIGH NEAR 90 IS NOT OUT OF THE QUESTION AROUND LUVERNE AND PIPESTONE. A LOW PRESSURE SYSTEM AND ASSOCIATED FRONTAL BOUNDARIES WILL MOVE INTO THE FA SUNDAY NIGHT. ELEVATED INSTABILITY DEVELOPS BY EVENING NORTH OF THE WARM FRONT ACROSS CENTRAL MN AND PUSHES INTO NORTHWEST WI DURING THE NIGHT. LOW LEVEL MOISTURE TRANSPORT INCREASES DRAMATICALLY ACROSS EAST CENTRAL MN AS THE LOW LEVEL JET INCREASE TO 40 KNOTS. LAPSE RATES ARE BETTER THAN 6.5 DEG C/KM ALONG WITH A FAVORABLE DIFFERENTIAL TEMPERATURE ADVECTION PATTERN. THE CROSSOVER BETWEEN 850 AND 500 MB IS RATHER IMPRESSIVE BUT A LITTLE NORTH OF OUR CWA. ALL OF THIS POINTS TO SOME STORMS DEVELOPING ACROSS CENTRAL MN AND MOVING TOWARDS KDLH. A FEW STORMS WITH LARGE HAIL MAY OCCUR. THERE STILL REMAINS MODEL SPREAD FROM MONDAY THROUGH TUESDAY ON MOVING THE LOW AND TRAILING COLD FRONT ACROSS THE FA. THE ECMWF REMAINS THE SLOWEST WHILE THE NAM IS THE FASTEST. THE GEM AND GEFS ARE PRETTY SIMILAR. TRIED TIMING PRECIPITATION BASED ON THIS COMBINATION. THIS YIELDED LIKELY POPS OVER EAST CENTRAL MN MONDAY AFTERNOON AND ACROSS PARTS OF WEST CENTRAL WI MONDAY EVENING. HIGH TEMPERATURES ON MONDAY MAY BE WARMER THAN FORECAST FOR SOUTHEAST AREAS OF THE FA IF THE CLOUDINESS/SHOWERS/THUNDERSTORMS DO NOT DEVELOP AS FORECAST. DRY WEATHER FORECAST IN THE WAKE OF THE FRONT FOR TUESDAY THROUGH FRIDAY AS HIGH PRESSURE STALLS OVER THE WESTERN GREAT LAKES. HIGHS DURING THE PERIOD FROM 55 TO 65 WITH LOWS FROM 35 TO 45. A PACIFIC COLD FRONT IS THEN PROJECTED ACROSS THE REGION FOR NEXT SATURDAY. HOWEVER...THE ECMWF REMAINS THE SLOWEST ON MOVING THE FRONT THROUGH ALONG WITH WEAKENING THE SYSTEM AS IT APPROACHES. FOR NOW...INDICATED ONLY A SMALL CHANCE FOR RAIN SHOWERS. && .AVIATION.../06Z TAF ISSUANCE/ DIFFICULT CEILING FCST THRU THE NEXT 24 HRS DUE TO THE SLOW PROGRESSION OF THE SFC FRONTS OVER WRN MN/ERN DAKOTAS COMBINED WITH THICK ENOUGH LOW CLOUDS PREVENTING MIXING. FOG SATELLITE PRODUCE SHOWS LARGE SWATH OF LOW STRATUS WITH FOG ENCOMPASSING THE AREA. WITH ONE TAF SITE...KAXN...ALREADY WELL INTO THE LIFR CATEGORY...SEE NO REASNO WHY THE OTHERS WOULD NOT GET THERE...ESP THOSE THAT WOULD BE E AND N OF THE SFC BOUNDARIES. WILL LOOK FOR ALL TAF SITES TO GET DOWN TO A VARIATION OF IFR-OR-WORSE...WHETHER FROM CIG OR VSBY...THROUGH DAYBREAK. ONCE PAST THE DEGRADED FLIGHT CONDS THROUGH DAYBREAK...QUESTION BECOMES HOW LONG WILL THE IFR- TO-MVFR CIGS LAST THROUGH THE AFTN. MODELS SUGGEST DELAYED PROGRESSION OF THE WMFNT OUT WEST...WHICH WOULD KEEP LOW LEVEL EAST-TO-SOUTHEAST WINDS IN PLACE THRU THE DAY AND HENCE THE LOW MOISTURE WHICH WOULD NOT MIX OUT WELL AND KEEP LOW STRATUS GOING. HAVE ADVERTISED THIS TREND FOR ALL BUT KAXN AND KRWF...WHICH WOULD BE MOST LIKELY TO CLEAR OUT. HIGH CIRRUS WOULD THEN PREVAIL THRU THE EVENING UNTIL HIGH CLOUDS LOWER AND THICKEN TMRW NIGHT. MSP...CIGS MAINTAINING AT LOWER-END MVFR AND WILL LOOK FOR THEM TO TOUCH INTO IFR BEFORE SLOWLY RISING OUT DURG THE DAY TMRW. HOWEVER...THAT RISE WILL BE SLOW SO WILL MAINTAIN MVFR CIGS THROUGH THE DAY. DIFFICULT TO TELL IF THE CIGS WILL BE ABOVE OR BELOW THE 1700 FT THRESHOLD BUT GIVEN THAT THE CHANGE HAS BEEN MADE TO DELAY CLEARING WITH THIS ISSUANCE...HAVE COMPROMISED AND KEPT THE LATE MRNG THRU AFTN CIGS AT 2000 FT. CLOUDS SCATTER OUT LATE DAY THEN HIGH CLOUDS FILL IN. OUTLOOK... /SUN NIGHT-MON NIGHT/...FRONTAL SYSTEM MOVING THRU WILL PRODUCE SHWRS AND TSTMS ACRS THE REGION. MVFR-IFR CONDS LIKELY. /TUE-THU/...VFR UNDER HIGH PRESSURE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
144 AM EDT SUN APR 1 2012 .SYNOPSIS... ISOLATED SHOWERS AND THUNDERSTORMS WILL LINGER OVER THE AREA AS A COLD FRONT MOVES SOUTH ACROSS THE AREA EARLY THIS MORNING...WITH DRY WEATHER SETTLING IN TODAY AND TONIGHT. A DRY COLD FRONT WILL DROP QUICKLY SOUTHEAST OVER THE AREA MONDAY. UNSETTLED CONDITIONS WILL RETURN BY MID WEEK...AS A LOW PRESSURE SYSTEM APPROACHES THE EASTERN CAROLINAS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 1030 PM SATURDAY...LATEST SFC ANALYSIS PLACES THE COLD FRONT PARTIALLY INTO NC...DROPPING FROM THE NORTH. THE CONVECTION ACROSS THE NE PORTION OF THE STATE IS BASICALLY ALONG THE COLD FRONT ITSELF. THE OUTFLOW FROM THIS CONVECTION IS AIDING THE COLD FRONTS PUSH SOUTHWARD...AND COULD REACH THE NORTHERN PORTIONS OF THE ILM CWA BY MIDNIGHT THROUGH 1 AM SUNDAY. SLIGHTLY FASTER THAN 1ST PROGGED WITH HRRR AND AN EARLIER NAM MODEL RUN. HRRR INDICATES 1 MORE POTENTIAL MINI ROUND OF CONVECTION TO PUSH THROUGH IMMEDIATELY AHEAD OF THE COLD FRONT. WILL CONTINUE WITH LOW CHANCE POPS THROUGH ROUGHLY 2 AM SUNDAY. LOOKING AT NAM 1K-8H PARTIAL THICKNESS PACKING AND HRRR HRLY WINDS...THE COLD FRONT WILL DROP NEARLY DUE SOUTH ACROSS THE FA BETWEEN 1AM AND 7AM SUNDAY. LOOK FOR NW WINDS TO VEER TO THE N-NE ALONG WITH A MINI CAA SURGE THAT WILL ONLY LAST THRU MIDDAY SUNDAY B4 SHUTTING OFF. WITH THREAT OF PCPN INTO THE EARLY AM HRS OF SUNDAY AND CLOUDS STICKING AROUND FOR MUCH OF THE REMAINDER OF THE NIGHT. HAVE KEPT FOG DEVELOPMENT AT A MINIMUM WITH AN INCREASED POTENTIAL FOR A BRIEF STRATUS DECK UP THRU 1-2 HRS AFTER DAYBREAK. HAVE KEPT OVERNIGHT LOWS STABLE AFTER INCREASING A DEGREE OR 3 EARLIER...ESPECIALLY THE SOUTHERNMOST LOCALES WHERE THE FROPA WILL COINCIDE WITH DAYBREAK. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 300 PM SATURDAY...COLD FRONT POSITIONED JUST OFFSHORE AT THE START OF THE PERIOD. NVA AND SOME DRY AIR ADVECTION THROUGH THE MID LEVELS OF THE COLUMN KEEP SUNDAY SUNNY...BUT TEMPS WILL WARM WELL INTO THE 70S WITH LACK OF ANY CAA AND ENHANCED RIDGING ALOFT. TEMPS REMAIN WELL ABOVE CLIMO SUNDAY NIGHT AS GRADIENT TIGHTENS BETWEEN RIDGE OF HIGH PRESSURE AND ADVANCING COLD FRONT FROM THE NORTH. THIS COMBINED WITH SOME INCREASING MID-LEVEL CLOUDINESS WILL KEEPS MINS IN THE MID/UPPER 50S. SHORTWAVE TROUGH ROTATING DOWN FROM NEW ENGLAND SPAWNS A SURFACE LOW IN THE MID ATLANTIC WHICH TRIES TO DRIVE A COLD FRONT THROUGH EARLY MONDAY. WITH N/NW FLOW ALOFT...ANTICIPATE THIS FRONT TO WORK ALL THE WAY SOUTH THROUGH THE CWA BY AFTN. DURING FROPA...MID LEVEL LAPSE RATES STEEPEN AND FORECAST SOUNDINGS DEPICT INCREASING SATURATION IN THE 800-500MB LAYER. FORCING IS NOT STRONG...BUT WILL ADD A SCHC POP FOR TSTMS MONDAY...DECREASING FROM NORTH TO SOUTH THROUGH THE AFTN. THIS FRONT WILL MAKE FOR A DIFFICULT TEMP FORECAST MONDAY AS WELL...WITH 850MB TEMPS POSSIBLY FALLING THROUGH PEAK HEATING...ESPECIALLY ACROSS NE ZONES. EXPECT TEMPS TO RANGE FROM THE UPPER 80S IN THE TYPICAL WARM PEE DEE LOCATIONS...TO AROUND 80 IN THE NORTHEAST ZONES...EVEN WITH FAVORED DOWNSLOPE COMPRESSIONAL WARMING OCCURRING. FRONT STALLS SOUTH OF THE AREA AND SOME ISENTROPIC LIFT BEGINS LATE MONDAY NIGHT...ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE CWA. WILL RAMP POP BACK UP TO SCHC ACROSS THE SOUTH. MINS WILL FALL TO AROUND 50 ACROSS THE NORTHEAST CWA...TO NEAR 60 IN THE SOUTH. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 300 PM SATURDAY...AMPLITUDE WILL ONCE AGAIN BE THE NAME OF THE GAME FOR THE EXTENDED AS A LARGE MID LEVEL CYCLONE WILL BE WOBBLING OVER THE FOUR CORNERS REGION INITIALLY WITH RIDGING JUST WEST OF OUR REGION. AT THE SURFACE A FRONT WILL RESIDE JUST TO THE SOUTHWEST BEFORE GETTING WASHED OUT WEDNESDAY. A BACKDOOR FRONT WILL MOVE ACROSS THURSDAY INCREASING THE WEAK FORCING MECHANISMS IN PLACE...THIS AS THE MID LEVEL PATTERN AMPLIFIES SLIGHTLY. FINALLY LATE THURSDAY AND FRIDAY THE MAIN SYSTEM ASSOCIATED WITH THE PREVIOUSLY MENTIONED MID LEVEL LOW MOVES ACROSS. BOTTOM LINE...I HAVE INCREASED POPS FROM TUESDAY THROUGH THURSDAY INCREMENTALLY BASED ON A DIURNAL SCENARIO. THE NEW DAY...SATURDAY LOOKS DRY AT THIS POINT BUT THE INHERIT DIFFICULTIES OF FORECASTING A CLOSED SYSTEM THIS FAR OUT IN TIME MAKE FOR A LOW CONFIDENCE DRY FORECAST. REGARDING TEMPERATURES...HAVE INCREASED TEMPERATURES A BIT ACROSS THE BOARD TO MATCH GUIDANCE AND ADJACENT OFFICES BUT OVERALL TRENDS OF SLIGHTLY ABOVE EARLY TREND TO NEAR NORMAL LATE REMAIN INTACT. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 06Z...CONVECTION ASSOCIATED WITH COLD FRONT WILL DROP INTO THE NORTHERN TERMINALS SHORTLY AFTER TAF ISSUANCE. THE CONVECTION WILL BE WANING WITH MVFR/IFR CONDITIONS INTO DAYBREAK BEHIND THE FRONT. WINDS WILL SHIFT TO THE NORTHEAST...WITH MODERATE CONFIDENCE FOR AN IFR/NEAR MVFR CEILING. SOME MVFR VISIBILITIES ARE POSSIBLE BUT LESS LIKELY. THE STRATUS SHOULD MIX OUT AROUND 14Z...BUT TAKE A BIT LONGER WITH THE NORTHEAST WIND SURGE. WINDS WILL VEER TO EAST NORTHEAST...THEN SOUTHEAST ALONG THE COAST IN THE AFTERNOON WITH THE RESULTANT WIND FROM A WEAK TO MODERATE SEA BREEZE. EXTENDED OUTLOOK...LOW CONFIDENCE SHOWERS/ISOLATED THUNDERSTORM MONDAY AND TUESDAY. SCATTERED CONVECTION POSSIBLE WEDNESDAY WITH A BETTER CHANCE FOR PRECIP ON THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...LATEST OBSERVATIONS OVER THE ILM NC WATERS INDICATE SEAS STILL RUNNING WITHIN SCA THRESHOLDS ACROSS THE OUTER WATERS OFF CAPE FEAR. THE SCA WILL REMAIN THRU MIDNIGHT WHICH IS AMPLE TIME FOR THESE SEAS TO SUBSIDE BELOW SCA THRESHOLDS. GUIDANCE CONTINUES TO FURTHER SUBSIDE SEAS DURING THE PRE-DAWN HRS OF SUNDAY AS A COLD FRONT DROPS SOUTH ACROSS THE ILM WATERS BETWEEN 1 AM AND 7 AM SUNDAY. WINDS WILL VEER TO THE N-NE AFTER FROPA AND AID IN KNOCKING DOWN THE BUILT UP SHORT PERIOD SW WIND DRIVEN SEAS FROM THE PAST 1-2 DAYS. COULD SEE THE LAST ROUND OF CONVECTION MOVE OFF THE MAINLAND THROUGH 2 AM SUNDAY. OTHERWISE...LOOK FOR A N-NE MINI SHORT LIVED COLD SURGE BEHIND THE COLD FRONT...LASTING THROUGH MID TO LATE SUNDAY MORNING. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 PM SATURDAY...COLD FRONT WILL BE POSITIONED OFFSHORE AT THE START OF THE PERIOD WITH N/NE WINDS ONGOING ACROSS THE WATERS. RIDGE OF HIGH PRESSURE BUILDS IN FROM THE SOUTH DURING THE AFTN AND WINDS BECOME LIGHT...VEERING TO THE SW THROUGH THE EVE AS A PRE FRONTAL AIRMASS MOVES OVER THE AREA AND INCREASING RAPIDLY TO 15-20 KTS SUN NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. COLD FRONT DROPS SOUTH DURING MONDAY...AND WINDS WILL GRADUALLY VEER FROM SW TO N...THEN NE MONDAY NIGHT...ALL AT SPEEDS OF AROUND 10 KTS. LACK OF ANY MEANINGFUL SWELL WITHIN THE WAVE SPECTRUM MEANS THAT SEAS WILL BE PRIMARILY WIND DRIVEN...2-3 FT THROUGH THE PERIOD...WITH A COMBINATION OF NE AND SW CHOP SUNDAY...BECOMING DOMINATED BY NE WAVE ON MONDAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 PM SATURDAY...MAIN EVENT FOR THE MARINE COMMUNITY WILL BE THE BACK DOOR FRONT MOVING ACROSS THURSDAY. THIS FRONT WILL EVENTUALLY BRING ALL WINDS AROUND TO NORTHEAST BUT FOR MOST OF THE DAY THURSDAY THE NORTH CAROLINA AND SOUTH CAROLINA WATERS WILL BE DIVIDED BY THE FRONT. FOR EARLIER IN THE PERIOD...EASTERLY WINDS INITIALLY WITH A SOUTH TO SOUTHWESTERLY FLOW DEVELOPING LATER TUESDAY AND PREVAILING THROUGH WEDNESDAY. SEAS ARE GENERALLY 2-4 FEET WITH WINDS WAVES DOMINATING THE SPECTRUM. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH/COLBY SHORT TERM...JDW LONG TERM...SHK AVIATION...HDL/COLBY
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
350 AM CDT SUN APR 1 2012 .DISCUSSION...THE DENSE FOG IS BECOMING MORE WIDESPREAD AND ADVECTING TO THE NORTH AND WEST ACCORDING TO WEB CAMS AND OBSERVATIONS. THE HRRR IS DOING AN EXCELLENT JOB WITH THIS FOG...AND WILL FOLLOW FOR THE FORECAST. ISSUED A DENSE FOG ADVISORY FOR AREAS ALONG AND SOUTH OF A VALLEY CITY TO GRAND FORKS TO BAUDETTE LINE. RADAR SHOWS SHOWERS NEAR THE INTERNATIONAL BORDER...AND THESE WILL BE NORTH OF THE DENSE FOG AREA. FAIRLY CONFIDENT THAT THE DENSE FOG WILL BE ABLE TO ADVECT INTO THE VALLEY CITY...FARGO...AND GRAND FORKS AREAS. && .AVIATION...LIFR/IFR CIGS/VSBY WILL CONTINUE TO ADVECT NORTHEAST FROM WEST CENTRAL MINNESOTA INTO THE EARLY MORNING HOURS. THE MAIN QUESTION WILL BE HOW FAR TO THE NORTH/WEST THESE CONDITIONS WILL ADVECT. CURRENT HI-RES MODEL GUIDANCE SUGGESTS THAT A SURE BET WILL BE KBJI AND KFAR...WHILE KGFK AND KTVF WILL BE ON THE EDGE...AND KDVL SHOULD REMAIN VFR. MOST GUIDANCE SUGGESTS ALL SITES VFR BY 18Z. GUSTY SOUTHEAST WINDS EXPECTED TO DEVELOP BY AFTERNOON. && .PREV DISCUSSION... /ISSUED 310 AM CDT SUN APR 1 2012/ SHORT TERM (SUN-TUE)...INTERESTING FORECAST WITH MULTIPLE CHALLENGES. MODEL DIFFERENCES ARISE ON MONDAY WITH TIMING OF FRONT. GEM/ECMWF SLOW WHILE NAM/GFS QUICKER. ECMWF HAS BEEN CONSISTENT WITH THE SLOW SOLUTION...BUT HAD BEEN AN OUTLIER UNTIL THIS SET OF MODEL RUNS WITH THE GEM TRENDING SLOWER. WILL HAVE TO FOLLOW A BLEND. UPPER RIDGE BUILDING INTO THE REGION FOR TODAY. AHEAD OF THIS UPPER RIDGING...SCATTERED SHOWERS ASSOCIATED WITH WEAK WAVE (WARM AIR ADVECTION) POSSIBLE DURING THE EARLY MORNING HOURS...EXITING THE NE FA BY NOON. LOW-LEVEL FLOW IS INCREASING FROM THE SOUTHEAST...AND ADVECTING LOW LEVEL MOISTURE (LOW CLOUDS/FOG) BACK INTO THE REGION FROM CENTRAL MINNESOTA. FOLLOWING HRRR...EXPECT THESE CIGS TO ADVECT INTO ALL BUT THE FAR NORTHERN FA BY 12Z...THEN SCATTER WITH DAYTIME HEATING AND STRONG SE WINDS BY MID TO LATE MORNING. DENSE FOG POSSIBLE UNTIL MID-MORNING...AND WILL MONITOR CONDITIONS FOR POSSIBLE ADVISORY. SO FAR DENSE FOG IS NOT TOO WIDESPREAD...BUT HRRR SUGGESTS THAT DENSE FOG WILL BECOME WIDESPREAD BY 05Z. WINDS WILL BE CLOSE TO ADVISORY CRITERIA THIS AFTERNOON...BUT PARAMETERS SUGGEST JUST BELOW. WITH SOLAR AND GOOD MIXING...EXPECT FULL HEATING POTENTIAL...WITH MAX TEMPS AROUND 80F ACROSS THE SW FA TO UPPER 60S ACROSS THE NE FA. EXPECTED TEMP VALUES ALONG AND WEST OF THE VALLEY WILL BE RECORD HIGHS. UPPER RIDGING WILL BE BRIEF WITH UPPER FLOW BECOMING SOUTHWEST TONIGHT. STRONG 850MB JET WILL DEVELOP AND TRANSPORT MOISTURE ALONG AND AHEAD COLD FRONT. FOLLOWING MODEL COMPROMISE FOR TIMING...BEST PRECIP CHANCES WILL BE ALONG AND EAST OF THE VALLEY...FROM 06Z MON INTO THE AFTERNOON HOURS. 850MB CAPE 1000-1500 J/KG INTO THE EARLY MORNING ALONG WITH STRONG LOW-LEVEL JET ACROSS SE FA COULD LEAD TO ISOLD SEVERE HAIL (SPC HAS A 5% PROBABILITY)...ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL. UPPER TROUGH SWINGS THROUGH BY MON NIGHT. AS THIS FEATURE APPROACHES CANNOT RULE OUT SHOWERS ANYWHERE ON MONDAY...BUT HEAVIEST RAINFALL SHOULD BE IN MINNESOTA COUNTIES (AHEAD OF COLD FRONT WHERE PWATS ARE HIGHEST). CLOUDS AND COOLER AIRMASS WILL LEAD TO MUCH COLDER TEMPS ON MONDAY (ALTHOUGH STILL ABOVE NORMAL). RIDGING MOVES BACK INTO THE REGION ON TUESDAY...AND TEMPS BEGIN TO TREND WARMER AGAIN. LONG TERM (WED-SAT)...RIDGING DOMINATES INTO FRIDAY BEFORE MOVING TO THE EAST ALLOWING SW FLOW ALOFT. DRY AND WARM CONDITIONS SHOULD TRANSITION TO COOLER AND WETTER BY SATURDAY IF MODELS HAVE TIMING CORRECT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NDZ027-029- 030-038-039-049-052-053. MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ001>003- 006-008-009-013>017-022>024-027>032-040. && $$ TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
349 AM CDT SUN APR 1 2012 .SHORT TERM...TODAY THROUGH MONDAY... RECORD WARMTH AND CRITICAL FIRE WEATHER WILL HIGHLIGHT THE SHORT TERM FORECAST FOR TODAY...FOLLOWED BY COOLER...BUT STILL ABOVE NORMAL TEMPERATURES FOR MONDAY WITH MARGINAL FIRE WEATHER CONCERNS. FOR THIS MORNING ADDED A PATCHY FOG MENTION TO THE JAMES RIVER VALLEY AS STRATUS AND FOG CONTINUE TO EXPAND EAST AS PROGGED BY THE LATEST HRRR MODEL RUNS OVERNIGHT. OTHERWISE...AS OF 08 UTC...BROAD SURFACE LOW PRESSURE WAS ANALYZED ACROSS MUCH OF CENTRAL AND EASTERN MONTANA...WITH TWO DISTINCT CIRCULATIONS ACROSS FAR SOUTHEAST MONTANA AND SOUTHEAST ALBERTA...WITH A COLD FRONT ACROSS CENTRAL MONTANA AND A WARM FRONT FROM NEAR HAVRE MONTANA THROUGH FAR SOUTHEAST SOUTH DAKOTA. THE OVERALL PROPAGATION OF THE SYSTEM HAS SLOWED...WITH THE COLD FRONT FORECAST TO REACH THE NORTH DAKOTA BORDER CLOSER TO 18 UTC...WITH THE SURFACE WARM FRONT AT THAT TIME EXTENDING FROM APPROXIMATELY CROSBY THROUGH LINTON. NEAR TO RECORD BREAKING HIGH TEMPERATURES ARE FORECAST IN THE WARM SECTOR OF THE SURFACE LOW ACROSS MUCH OF WESTERN AND CENTRAL NORTH DAKOTA ENHANCED BY COMPRESSIONAL HEATING AND MIXING JUST AHEAD OF THE COLD FRONT. SHOWN BELOW ARE FORECAST HIGHS AND RECORDS FOR TODAY FOR SELECT LOCATIONS ACROSS THE AREA. SITE FORECAST RECORD YEAR DICKINSON 76 74 1964 MINOT 78 72 1928 BISMARCK 82 75 1976 JAMESTOWN 78 78 1907 WILLISTON 70 72 1991 OVERALL THE DETERMINISTIC AND STATISTICAL GUIDANCE SUITE LOW LEVEL THERMAL FIELDS ARE IN GOOD AGREEMENT...AND CHOSE TO GO A COUPLE OF DEGREES ABOVE THE CONSENSUS GIVEN THE EFFECTS OF BROWN VEGETATION ENHANCING MIXING HEIGHTS. THE AFOREMENTIONED COLD FRONT IS EXPECTED TO PROPAGATE AS FAR EAST AS NORTH DAKOTA HIGHWAY 3 BY LATE AFTERNOON. THE WIND FIELD BEHIND THE COLD FRONT IS FORECAST TO BE SLIGHTLY WEAKER COMPARED TO PREVIOUS FORECASTS...WITH THE 01/00 UTC NAM/GFS BUFR SOUNDINGS INDICATING A WEAK INVERSION NEAR 800-750 MB...WHICH WILL LIMIT MIXING HEIGHTS. THAT SAID...POST FRONTAL WINDS SUSTAINED TO NEAR 20 KTS WITH GUSTS OF 25-30KTS ARE EXPECTED WITH MINIMUM RH VALUES OF 15 TO 25 PERCENT WITH POST FRONTAL TEMPERATURES STILL IN THE 60S AND 70S. WHEN COMBINED WITH THE ABUNDANCE OF DRY FUELS AND LACK OF GREEN UP....VERY HIGH FIRE DANGER IS FORECAST ACROSS MUCH OF THE AREA...WITH EXTREME FIRE DANGER ACROSS THE FAR SOUTHWEST. THE CURRENT RED FLAG WARNING LOOKS GOOD...EXCEPT FOR THE FAR EASTERN TIER OF COUNTIES WHICH MAY NOT SEE FRONTAL PASSAGE UNTIL THE EARLY EVENING...AND THUS NOT MEET CRITERIA. HOWEVER...IT WILL BE CLOSE AND WILL LEAVE THE WARNING AS IS FOR NOW. FOR TONIGHT...STRONG ISALLOBARIC FORCING VIA AN 8-10 MB/6 HR PRESSURE RISE BUBBLE IS FORECAST ACROSS MUCH OF WESTERN AND CENTRAL NORTH DAKOTA BEHIND THE COLD FRONT. THE QUESTION WILL BE HOW WELL THE BOUNDARY LAYER WILL BE ABLE TO STAY MIXED AFTER SUNSET. AT THIS TIME THE BEST POTENTIAL LOOKS TO BE ACROSS THE SOUTHWEST AND SOUTH CENTRAL...WHERE LITTLE CHANGE IN WIND MAGNITUDE IS POSSIBLE EVEN AFTER SUNSET...WHICH IS OF CONCERN FOR ANY ONGOING FIRES THAT MAY START TODAY. GIVEN THE EXPECTED MIXING CWA WIDE...FOLLOWED A CONSENSUS OF 01/00 UTC NAM/GFS FOR OVERNIGHT LOWS...WHICH YIELDS WIDESPREAD 40S FOR NEARLY ALL OF THE CWA...WITH LOWS POSSIBLY AS WARM AS 50 ACROSS THE SOUTH CENTRAL. MONDAY LOOKS TO BE COOLER...WITH HIGHS IN THE 50S WITH GOOD AFTERNOON MIXING CWA WIDE. HOWEVER...TEMPERATURES ARE STILL FORECAST TO BE 5 TO 10 DEGREES ABOVE NORMAL. DESPITE THE COOLER TEMPERATURES...MARGINAL FIRE WEATHER CONCERNS ARE POSSIBLE ACROSS THE FAR SOUTHWEST WHERE WIND GUSTS IN EXCESS OF 25 KTS MAY BE POSSIBLE...WITH RH VALUES OF 20-25 PERCENT. GIVEN THE MARGINAL NATURE OF THE THREAT AND TO AVOID CONFUSION WITH THE CURRENT FIRE WEATHER HEADLINES...WILL LET THE DAY SHIFT EVALUATE FURTHER. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY... THE MEDIUM RANGE MODELS ARE CONSISTENT WITH RESPECT TO THE SYNOPTIC PATTERN OVER THE NORTHERN PLAINS THROUGH THURSDAY. MODEL SOLUTIONS BEGIN TO DIVERGE WITH RESPECT TO THE UPPER PATTERN FRIDAY AND SATURDAY. AS A RESULT...USED A BLEND OF SOLUTIONS FOR THE END OF THE WEEK. A REX BLOCK/HIGH OVER LOW PATTERN WILL TRAVERSE ACROSS THE GREAT PLAINS TUESDAY THROUGH THURSDAY. THIS WILL GENERATE DRY CONDITIONS AND A GRADUAL WARMING TREND ACROSS NORTH DAKOTA THROUGH MID-WEEK WITH HIGHS GENERALLY IN THE UPPER 60S TO LOWER 70S BY THURSDAY. MODEL SOLUTIONS BEGIN TO DIVERGE WITH RESPECT TO A POSSIBLE LATE SEASON WINTER STORM EXPECTED TO IMPACT THE REGION THURSDAY NIGHT THROUGH SATURDAY. THE MAIN QUESTIONS ARE WHEN EXACTLY THIS SYSTEM WILL BEGIN TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA AND WHAT THE PRECIPITATION TYPE WILL BE. AS IS TYPICAL WITH HIGH IMPACT WEATHER SYSTEMS...THE ECMWF IS THE SLOWEST SOLUTION RELATIVE TO THE GFS/GEM. IT PAINTS QPF ACROSS WESTERN NORTH DAKOTA ALONG A STRONG BAROCLINIC ZONE FRIDAY AFTERNOON WHEREAS THE GFS/GEM IS ABOUT 12-18 HOURS FASTER BEGINNING PRECIP WEST THURSDAY NIGHT. WOULD LIKE TO SIDE WITH THE ECMWF GIVEN ITS SUPERIOR PERFORMANCE IN THE EXTENDED. HOWEVER...THE HIGH UNCERTAINTY WARRANTS A BROAD BRUSHING OF POPS FOR THE THURSDAY NIGHT THROUGH SATURDAY PERIOD WITH THE HIGHEST POPS WEST. AS THIS SYSTEM MOVES ACROSS THE STATE...ITS SURFACE REFLECTION IS PROGGED TO GENERATE VERY WINDY CONDITIONS ACROSS WESTERN AND CENTRAL NORTH DAKOTA DURING THE FRIDAY NIGHT/SATURDAY PERIOD. IN ADDITION...WRAP-AROUND MOISTURE COMBINED WITH 850MB TEMPERATURES FALLING BELOW ZERO SHOULD ALLOW FOR A WINTRY MIX OF PRECIPITATION TO DEVELOP FRIDAY NIGHT WITH PRIMARILY SNOW EXPECTED NORTHWEST BY SATURDAY. THE COMBINATION OF HIGH WINDS AND WINTRY PRECIPITATION COULD MAKE FOR AN INTERESTING WEEKEND. STAY TUNED. && .AVIATION... PRIMARILY VFR CONDITIONS ARE EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE TAF PERIOD. LIGHT SHOWERS WILL CONTINUE TO IMPACT KMOT THROUGH THE MORNING HOURS. EXPECT E/SE WINDS THIS MORNING AHEAD OF A STRONG FRONT THAT WILL SWEEP THROUGH NORTH DAKOTA TODAY. WINDS WILL BECOME W/NW BEHIND THE FRONT AND GUST AROUND 30 KTS IN THE AFTERNOON AT ALL SITES EXCEPT FOR KJMS. && .FIRE WEATHER... A COLD FRONT IS FORECAST TO ENTER FAR WESTERN NORTH DAKOTA NEAR MID DAY TODAY...AND PUSH AS FAR EAST AS NORTH DAKOTA HIGHWAY 3 BY LATE AFTERNOON. WIDESPREAD NEAR TO RECORDING BREAKING HIGH TEMPERATURES INTO THE MID TO UPPER 70S...TO PERHAPS THE LOWER 80S ARE FORECAST AHEAD OF THE COLD FRONT. BEHIND THE FRONT...GOOD MIXING SHOULD ALLOW FOR SUSTAINED WESTERLY WINDS TO 25 MPH WITH GUSTS APPROACHING 35 MPH...AS RH VALUES FALL TO 15 TO 25 PERCENT WITH TEMPERATURES STILL IN THE 60S AND 70S. THE FAR EASTERN TIER OF COUNTIES IN THE RED FLAG WARNING MAY NOT SEE FRONTAL PASSAGE UNTIL THE EARLY EVENING...AND THUS NOT MEET CRITERIA. HOWEVER...IT WILL BE CLOSE AND WILL LEAVE THE WARNING AS IS FOR NOW. FOR TONIGHT...STRONG WINDS MAY CONTINUE THROUGH MUCH OF THE OVERNIGHT...ESPECIALLY ACROSS THE SOUTHWEST AND SOUTH CENTRAL...WITH NORTHWEST WINDS OF SIMILIAR SPEEDS AS SEEN PRIOR TO SUNSET LASTING THROUGH THE NIGHT. MONDAY LOOKS TO BE COOLER AND BREEZY BEHIND THE FRONT WITH HIGHS IN THE 50S AND RH VALUES FALLING TO 20 TO 30 PERCENT FOR MOST AREAS WITH AFTERNOON MIXING. THE COOLER TEMPERATURES AND SLIGHTLY HIGHER RH VALUES WILL HELP TO LIMIT THE OVERALL THREAT. THE AREA OF MOST CONCERN FOR POSSIBLY REACHING CRITICAL VALUES IS THE FAR SOUTHWEST...WHERE STRONGER NORTHWEST WINDS OF 20 TO 30 MPH ARE POSSIBLE. HOWEVER...TO AVOID CONFUSION WITH THE CURRENT FIRE WEATHER HEADLINES...WILL LET THE DAY SHIFT EVALUATE FURTHER. && .BIS WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 10 PM CDT /9 PM MDT/ THIS EVENING FOR NDZ009>012-017>023-031>036-040>047-050. && $$ SHORT TERM/FIRE...AYD LONG TERM/AVIATION....TM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
310 AM CDT SUN APR 1 2012 .SHORT TERM (SUN-TUE)...INTERESTING FORECAST WITH MULTIPLE CHALLENGES. MODEL DIFFERENCES ARISE ON MONDAY WITH TIMING OF FRONT. GEM/ECMWF SLOW WHILE NAM/GFS QUICKER. ECMWF HAS BEEN CONSISTENT WITH THE SLOW SOLUTION...BUT HAD BEEN AN OUTLIER UNTIL THIS SET OF MODEL RUNS WITH THE GEM TRENDING SLOWER. WILL HAVE TO FOLLOW A BLEND. UPPER RIDGE BUILDING INTO THE REGION FOR TODAY. AHEAD OF THIS UPPER RIDGING...SCATTERED SHOWERS ASSOCIATED WITH WEAK WAVE (WARM AIR ADVECTION) POSSIBLE DURING THE EARLY MORNING HOURS...EXITING THE NE FA BY NOON. LOW-LEVEL FLOW IS INCREASING FROM THE SOUTHEAST...AND ADVECTING LOW LEVEL MOISTURE (LOW CLOUDS/FOG) BACK INTO THE REGION FROM CENTRAL MINNESOTA. FOLLOWING HRRR...EXPECT THESE CIGS TO ADVECT INTO ALL BUT THE FAR NORTHERN FA BY 12Z...THEN SCATTER WITH DAYTIME HEATING AND STRONG SE WINDS BY MID TO LATE MORNING. DENSE FOG POSSIBLE UNTIL MID-MORNING...AND WILL MONITOR CONDITIONS FOR POSSIBLE ADVISORY. SO FAR DENSE FOG IS NOT TOO WIDESPREAD...BUT HRRR SUGGESTS THAT DENSE FOG WILL BECOME WIDESPREAD BY 05Z. WINDS WILL BE CLOSE TO ADVISORY CRITERIA THIS AFTERNOON...BUT PARAMETERS SUGGEST JUST BELOW. WITH SOLAR AND GOOD MIXING...EXPECT FULL HEATING POTENTIAL...WITH MAX TEMPS AROUND 80F ACROSS THE SW FA TO UPPER 60S ACROSS THE NE FA. EXPECTED TEMP VALUES ALONG AND WEST OF THE VALLEY WILL BE RECORD HIGHS. UPPER RIDGING WILL BE BRIEF WITH UPPER FLOW BECOMING SOUTHWEST TONIGHT. STRONG 850MB JET WILL DEVELOP AND TRANSPORT MOISTURE ALONG AND AHEAD COLD FRONT. FOLLOWING MODEL COMPROMISE FOR TIMING...BEST PRECIP CHANCES WILL BE ALONG AND EAST OF THE VALLEY...FROM 06Z MON INTO THE AFTERNOON HOURS. 850MB CAPE 1000-1500 J/KG INTO THE EARLY MORNING ALONG WITH STRONG LOW-LEVEL JET ACROSS SE FA COULD LEAD TO ISOLD SEVERE HAIL (SPC HAS A 5% PROBABILITY)...ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL. UPPER TROUGH SWINGS THROUGH BY MON NIGHT. AS THIS FEATURE APPROACHES CANNOT RULE OUT SHOWERS ANYWHERE ON MONDAY...BUT HEAVIEST RAINFALL SHOULD BE IN MINNESOTA COUNTIES (AHEAD OF COLD FRONT WHERE PWATS ARE HIGHEST). CLOUDS AND COOLER AIRMASS WILL LEAD TO MUCH COLDER TEMPS ON MONDAY (ALTHOUGH STILL ABOVE NORMAL). RIDGING MOVES BACK INTO THE REGION ON TUESDAY...AND TEMPS BEGIN TO TREND WARMER AGAIN. .LONG TERM (WED-SAT)...RIDGING DOMINATES INTO FRIDAY BEFORE MOVING TO THE EAST ALLOWING SW FLOW ALOFT. DRY AND WARM CONDITIONS SHOULD TRANSITION TO COOLER AND WETTER BY SATURDAY IF MODELS HAVE TIMING CORRECT. && .AVIATION...LIFR/IFR CIGS/VSBY WILL CONTINUE TO ADVECT NORTHEAST FROM WEST CENTRAL MINNESOTA INTO THE EARLY MORNING HOURS. THE MAIN QUESTION WILL BE HOW FAR TO THE NORTH/WEST THESE CONDITIONS WILL ADVECT. CURRENT HI-RES MODEL GUIDANCE SUGGESTS THAT A SURE BET WILL BE KBJI AND KFAR...WHILE KGFK AND KTVF WILL BE ON THE EDGE...AND KDVL SHOULD REMAIN VFR. MOST GUIDANCE SUGGESTS ALL SITES VFR BY 18Z. GUSTY SOUTHEAST WINDS EXPECTED TO DEVELOP BY AFTERNOON. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1149 PM CDT SAT MAR 31 2012 .DISCUSSION... LOOKS LIKE VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS. SEE THE BELOW AVIATION SECTION. && .AVIATION... LATEST MODELS DID NOT INDICATE ANY NEED FOR CHANGES TO THE CURRENT TERMINALS. GUSTY SOUTHWEST SURFACE WINDS TOMORROW AFTERNOON STILL LOOK LIKELY. HUBER && .PREV DISCUSSION... /ISSUED 635 PM CDT SAT MAR 31 2012/ DISCUSSION... EXPECT VFR CONDITIONS TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR THE NEXT 24 HOURS. AVIATION BELOW HAS ADDITIONAL INFORMATION. AVIATION... MODELS CONTINUE TO HOLD A SURFACE TROUGH OF LOW PRESSURE...AND AN ASSOCIATED SURFACE DRYLINE...IN THE TEXAS AND NEW MEXICO AREA FOR THE NEXT 24 HOURS. THE LATEST RUC INDICATES THE SURFACE PRESSURE GRADIENT WILL INCREASE ACROSS WEST CENTRAL TEXAS OVERNIGHT TONIGHT. THUS...LOOK FOR GUSTY SOUTHWEST SURFACE WINDS TO DOMINATE WEST CENTRAL TEXAS BY 06Z TONIGHT. FOR TOMORROW AFTERNOON...WATCH FOR STRONGER SOUTHWEST SURFACE WINDS AS THE SURFACE PRESSURE GRADIENT STRENGTHENS ACROSS WEST CENTRAL TEXAS. HUBER PREV DISCUSSION... /ISSUED 334 PM CDT SAT MAR 31 2012/ SHORT TERM... AN UPPER LEVEL RIDGE WILL AMPLIFY THROUGH TOMORROW AS IT BUILDS EAST OF THE FORECAST AREA AHEAD OF AN APPROACHING UPPER LEVEL TROUGH... WHICH WILL BE OVER THE SOUTHERN ROCKIES BY LATE TOMORROW. HOT AND DRY WEATHER WILL CONTINUE ACROSS WEST CENTRAL TEXAS TOMORROW WITH LOW TO UPPER 90S OVER THE CWA...THE WARMEST TEMPERATURES SHOULD BE OVER THE NORTHERN HALF OF THE CWA AS THE 850MB THERMAL RIDGE LIFTS FURTHER TO THE NORTH. 15 LONG TERM... THE DEEP CLOSED LOW OFF THE PACNW COAST WILL BE A PLAYER IN OUR WEATHER AS THE LONG TERM OPENS BUT THE MEDIUM RANGE MODELS CONTINUE TO STRUGGLE WITH THE TIMING. THE LATEST RUNS SUGGEST THAT THIS FEATURE WILL SLOW AS IT MOVES ACROSS THE SOUTHWEST CONUS...LIFTING NORTHEAST ACROSS THE TX PANHANDLE AFTER 00Z WEDNESDAY. THIS LATER ARRIVAL WILL LIKELY RESULT IN THE DRYLINE SETTING UP FARTHER WEST THAN PREVIOUS ANTICIPATED GIVEN WEAKER FORCING. STRONG SYNOPTIC LIFT /DEPICTED BY H5-H3 Q VECTOR CONVERGENCE/ IS PROGGED TO REMAIN WEST OF THE CWA UNTIL MONDAY NIGHT BY WHICH TIME THE DRYLINE WILL BE RETREATING. THUNDERSTORMS WILL BE POSSIBLE ALONG AND EAST OF THE DRYLINE LATE MONDAY AFTERNOON. SURFACE TEMPS IN THE MID/UPPER 80S AND DEWPOINTS WILL RESULT IN SIGNIFICANT INSTABILITY /SBCAPES OF 1500-3000/ BUT A SLOWER ARRIVAL OF SYNOPTIC ASCENT MAY RESULT IN THE CAP HOLDING STRONG AND LIMITING THE CONVECTIVE POTENTIAL /ESPECIALLY IN THE EAST IN THE AREA OF STRONGEST INSTABILITY/...MUCH OF THE CHAGRIN OF THE SOUTHERN PLAINS CHASE COMMUNITY. I OPTED TO MAINTAIN THE INHERITED POPS ON THE CENTRAL AND EAST ON MONDAY AFTERNOON BUT EXPANDED THEM WEST MONDAY NIGHT AND TUESDAY TO ACCOUNT FOR THE SLOWER TIMING. COOLER TEMPS ARE EXPECTED ON TUESDAY AS A PACIFIC COLD FRONT MOVES THROUGH THE AREA. I LOWERED MAX TEMPS INTO THE MID/UPPER 70S BUT FEEL I MAY STILL BE A FEW DEGREES ON THE WARM SIDE BASED ON H85 TEMPS. I AM NOT SOLD ON THE AGGRESSIVE RETURN OF SOUTHERLY FLOW SHOWN BY THE GFS AND LEANED MORE HEAVILY ON THE ECMWF SOLUTION IN THE POST FRONTAL ENVIRONMENT. WITH THAT SAID...I KEPT MAX TEMPS GENERALLY AT OR JUST BELOW 80 DEGREES ON WEDNESDAY BUT DRY CONDITIONS WILL RESULT IN A VERY PLEASANT DAY. MIN TEMPS TUESDAY NIGHT ARE EXPECTED TO BE IN THE MID/UPPER 50S...WARMING SLIGHTLY /LOWER 50S/ BY WEDNESDAY NIGHT. BY THURSDAY...THE H85 THERMAL RIDGE WILL BUILD BACK OVER THE AREA WITH INCREASING SOUTHERLY WINDS. TEMPS ARE EXPECTED TO WARM BACK INTO THE MID 80S. THESE SOUTHERLY WINDS WILL BRING THE LOW LEVEL MOISTURE BACK THURSDAY NIGHT AND FRIDAY. THE MODELS ARE HINTING AT SOME CONVECTION DEVELOPING OVER WEST TX FRIDAY EVENING ALONG THE DRYLINE BUT MY GUT SAYS THAT MOISTURE RETURN WILL NOT BE ADEQUATE TO SUPPORT MORE THAN FEW HIGH BASED STORMS. THUS...NO POPS WERE INCLUDED AT THIS TIME. HOWEVER...CONSIDERABLE UNCERTAINTY EXISTS AT THIS TIME. TEMPS WILL AGAIN BE WARM ON FRIDAY WITH HIGHS IN THE MID/UPPER 80S. THE GFS/DGEX DEPICT A WEAK COLD FRONT STALLING OVER THE AREA BY NEXT WEEKEND...ENHANCING RAIN CHANCES. HOWEVER...THE ECMWF KEEPS THIS BOUNDARY NORTH OF THE CWA IN CONJUNCTION WITH THE UPPER LEVEL SYSTEM. THE ECMWF ALSO PUSHES H5 HEIGHTS UP NEAR 585DM WITH THE MID LEVEL ANTICYCLONE CENTERED OVER DEEP SOUTH TX WHEREAS THE GFS KEEPS HEIGHTS AROUND 580DM WITH THE RIDGE CENTERED OVER THE GULF OF MEXICO. I WILL LET THE MODELS CONTINUE TO TEASE US OVER THE NEXT FEW DAYS BEFORE JUMPING ON ANY PARTICULAR SOLUTION. JOHNSON FIRE WEATHER... ELEVATED FIRE WEATHER CONDITIONS CAN BE EXPECTED SUNDAY OVER THE BIG COUNTRY...CONCHO VALLEY AND THE NORTHERN EDWARDS PLATEAU WITH UNSEASONABLY HOT TEMPERATURES IN THE 90S CONTINUING...ACCOMPANIED BY LOW RELATIVE HUMIDITY VALUES...AND SOUTHWEST WINDS BETWEEN 15 AND 20 MPH. CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE MAINLY WEST OF A LINE FROM HASKELL TO STERLING CITY SUNDAY AFTERNOON WITH 20 FOOT SOUTHWEST WINDS APPROACHING 20 MPH AND RELATIVE HUMIDITY VALUES DROPPING TO LESS THAN 10 PERCENT. 15 && .PRELIMINARY POINT TEMPS/POPS... ABILENE 65 96 65 85 52 / 0 0 0 20 30 SAN ANGELO 60 96 62 86 51 / 0 0 0 20 20 JUNCTION 62 93 64 87 51 / 10 10 10 20 30 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUBER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
205 AM EDT SUN APR 1 2012 .SYNOPSIS... WEAK HIGH PRESSURE WILL CONTINUE TO BUILD INTO OUR AREA TONIGHT. THIS HIGH WILL MOVE SOUTHEAST OF OUR AREA ON SUNDAY. ANOTHER APPROACHING COLD FRONT WILL ENTER OUR AREA BY MONDAY MORNING. && .NEAR TERM /THROUGH TODAY/... AS OF 945 PM EDT SATURDAY... PERSISTENT CLUSTER OF SCATTERED THUNDERSTORMS FROM GRAYSON COUNTY INTO WILKES COUNTY WAS GRADUALLY DRIFTING EAST. AREAS RADAR CONTINUES TO SHOW ISOLATED SHOWERS AND THUNDERSTORMS ON THE EASTERN AND SOUTHEAST FRINGE OF THE COUNTY WARNING AREA. LOCAL WRF AND HRRR GUIDANCE HAD PRECIPITATION ENDING ACROSS THE FORECAST AREA BY MIDNIGHT. ADJUSTED PROBABILITY OF PRECIPITATION IN THE FORECAST FOR THIS TIMING. ALSO ADDED PATCHY FOG IN FOG THE GREENBRIER RIVER VALLEY AND IN THE AREAS ACROSS THE SOUTHWEST COUNTY WARNING AREA THAT HAD RAIN SATURDAY AFTERNOON AND EVENING. DEW POINTS HAVE ALREADY DROPPED INTO THE UPPER 30S TO LOWER 40S IN THE FAR NORTHERN COUNTY WARNING AREA. SURFACE DEW POINTS WILL CONTINUE TO LOWER BEHIND THE FRONT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA. HAD MADE SLIGHT ADJUSTMENTS TO OVERNIGHT LOWS BASED ON 9PM OBS...CLOUD COVER AND THE LATEST LAMP GUIDANCE. NAM AND LOCAL WRF HAD LAYER OF LOW CLOUDS SPREADING ACROSS CENTRAL AND EASTERN VIRGINIA OVERNIGHT...AND REACHING AS FAR WEST AS LYNCHBURG AND DANVILLE. HAVE ADDED MORE CLOUD COVER IN THE EAST SINCE CEILINGS ARE ALREADY LOWERING JUST NORTH AND EAST OF THE FORECAST AREA. THE CLOUDS IN THE EAST MAY TAKE MOST OF THE MORNING TO MIX OUT. BUFKIT SOUNDINGS WERE SUGGESTING THAT CLOUDS MAY NOT BECOME SCATTERED UNTIL AFTER 11AM. AS OF 330 PM EDT SATURDAY... SURFACE ANALYSIS INDICATES THAT THE COLD FRONT IS LOCATED ACROSS OUR SOUTHERNMOST TIER OF COUNTIES THIS AFTERNOON...AND IS CONTINUING TO MOVE SOUTHEAST. RADAR HAS INDICATED THAT SPOTTY SHOWER ACTIVITY...AND A FEW THUNDERSTORMS...HAS DEVELOPED ACROSS OUR AREA WITH AFTERNOON HEATING...BUT NONE OF THIS ACTIVITY IS VERY STRONG. THAT STATED...CANNOT RULE OUT ONE OR TWO STRONG BUT SHORT LIVED THUNDERSTORMS DEVELOPING DURING EARLY EVENING. WEAK HIGH PRESSURE WILL CONTINUE TO BUILD INTO OUR AREA THIS EVENING...WHICH WILL RESULT IN NORTHWESTERLY FLOW THROUGH THE FIRST FEW HOURS OF SUNDAY MORNING. THIS DOWNSLOPE FLOW WILL ALLOW CLOUD COVER TO DIMINISH ACROSS MUCH OF OUR AREA...ESPECIALLY AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. HOWEVER...WEATHER FORECAST MODELS HAVE INDICATED THE POSSIBILITY OF LOW CLOUDS REDEVELOPING TONIGHT ALONG THE EAST FACING SLOPES IN SOUTHEAST WEST VIRGINIA AND THE MOUNTAIN EMPIRE...AS RESIDUAL LOW LEVEL MOISTURE BECOMES WEDGED ALONG THE RIDGELINES. WITH LIGHT WINDS ACROSS THE AREA...WILL ALSO BE LOOKING AT THE POSSIBILITY OF PATCHY FOG DEVELOPING ACROSS PORTIONS OF THE MOUNTAINS...ESPECIALLY IN THE RIVER VALLEYS. THE HIGH WILL SLIDE SOUTHEAST BY SUNRISE SUNDAY MORNING...AND WE WILL BEGIN TO SEE SOUTHERLY WINDS TAKE OVER. WITH PLENTY OF DRY AIR ALOFT...EXPECT THAT ANY FOG AND LOW CEILINGS WILL BURN OFF BY 10 AM...AND EXPECT MOSTLY CLEAR SKIES THROUGH EARLY AFTERNOON AREAWIDE. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... AS OF 330 PM EDT SATURDAY... ON SUNDAY NIGHT...THE NORTHEAST U.S. UPPER TROF DEEPENS IN RESPONSE TO A SHORTWAVE MOVING SOUTHEAST. THIS WILL DRIVE A COLD FRONT THROUGH THE FORECAST AREA AND SPARK A COMPLEX OF STORMS AS LOW LEVEL THETA-E RIDGE INCREASES IN ADVANCE OF THE FRONT. BEST LOW LEVEL CONVERGENCE WILL BE FOUND SE WV AND WEST OF I-77 WHERE HIGHEST POPS WERE PLACED. INCREASED LOW TEMPERATURES A COUPLE OF DEGREES WITH A FAIR AMOUNT OF CLOUDS AND MIXING. AS WEAK HIGH PRESSURE TRIES TO WEDGE DOWN THE EASTERN U.S. A WEAK LOW LEVEL CONVERGENCE ZONE IS ESTABLISHED IN THE FAR SOUTHWEST PORTION OF THE FORECAST AREA. WITH THE GREATEST INSTABILITY EXPECTED TO BE LOCATED HERE...WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE. LEANED TOWARD THE COOLER NAM MOS GUIDANCE FOR HIGHS IN THE EAST WITH A LOW LEVEL NORTHEAST FLOW IN PLACE. FOR MONDAY NIGHT AND TUESDAY...AN UPPER LEVEL RIDGE TRIES TO BUILD OVER THE REGION...BUT IS QUICKLY FLATTENED BY A NORTHERN STREAM SYSTEM MOVES ACROSS SOUTHERN CANADA AND THE NORTHERN GREAT LAKES. THE LOW LEVEL FLOW IN ADVANCE OF THIS SYSTEM COMES AROUND TO THE SOUTH/SOUTHWEST USHERING IN HIGHER DEWPOINTS AND POTENTIALLY A DECK OF LOW LEVEL STRATUS CLOUDS WITH GOOD MOISTURE ADVECTION. ISENTROPIC LIFT ON THE LEADING EDGE OF THIS MAY BRING ANOTHER ROUND OF RAIN THE FAR SOUTHWEST MONDAY NIGHT...WITH SHOWERS AND THUNDERSTORMS DEVELOPING IN ADVANCE OF THE FRONT IN THE NORTHERN AND WESTERN PORTION OF THE FORECAST AREA ON TUESDAY UNDER THE INSTABILITY AXIS. TEMPERATURE FORECAST TUESDAY IS A TRICKY ONE AND HIGHS WILL DEPEND ON THE AMOUNT OF CLOUD COVER SEEN. WITH THE POTENTIAL FOR LOW CLOUDS TO ADVANCE INTO OUR AREA...DROPPED HIGHS A FEW DEGREES TOWARD THE COOLER LOCALLY DERIVED MOS FORECAST HIGHS. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 330 PM EDT SATURDAY... FOR THE LONG TERM PORTION OF THE FORECAST...WE LEANED HEAVILY ON THE 00Z ECMWF SOLUTION WHICH SHOWS BETTER RUN TO RUN CONSISTENCY COMPARED TO THE GFS WITH ITS HANDLING OF THE TIMING AND EVOLUTION OF A CUT OFF LOW DRIFTING ACROSS THE SOUTHERN PLAINS...THEN THE SOUTHEAST U.S. LATE IN THE PERIOD. THE ECMWF IS ALSO IN BETTER AGREEMENT WITH THE CANADIAN AND UKMET SOLUTIONS. THE GFS ENSEMBLE MEMBERS SHOW A WIDE RANGE OF POTENTIAL SOLUTIONS TO THE STRENGTH AND LOCATION OF THIS UPPER LEVEL LOW WHICH GIVES US LOW CONFIDENCE IN THE OPERATIONAL GFS SOLUTION. SOME SIGNIFICANT MODIFICATIONS WERE MADE TO THE FORECAST BASED ON THE ECMWF FORECAST. FIRST...WITH THE SLOWER TIMING...NOW EXPECT THE COLD FRONT TO MOVE THROUGH LATE WEDNESDAY...ALLOWING TEMPERATURES TO BE WELL ABOVE NORMAL WITH A DEEP WEST...DOWNSLOPING FLOW...WITH THUNDERSTORMS POSSIBLE ALONG THE FRONT. BEHIND THIS FRONT...TRENDED TEMPERATURES DOWN BY SEVERAL DEGREES THUR-SATURDAY AS A LOW LEVEL NORTHEAST...THEN EAST...FLOW DEVELOPS WITH THE UPPER LOW TO OUR SOUTH AND CANADIAN HIGH PRESSURE BUILDING IN THE NE U.S. WITH THE NAO FORECAST TO BECOME NEGATIVE AND THE GLOBAL WIND OSCILLATION (GWO) IN A FAVORABLE PHASE FOR COOLER THAN NORMAL CONDITIONS IN THE EASTERN U.S...THE COOLER ECMWF TEMPERATURES APPEAR REASONABLE. DEPENDING ON THE LOCATION OF THE UPPER LOW...SHOWERS/RAIN WILL BE POSSIBLE EACH DAY...ESPECIALLY FOR THOSE FAVORED EASTERN UPSLOPE AREAS AND TO THE SOUTH...CLOSER TO THE LOCATION OF THE UPPER LOW. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 200 AM EDT SUNDAY... WEAK SURFACE HIGH PRESSURE BUILDING SOUTH OUT OF NEW ENGLAND RESULTING IN NORTHEASTERLY MOIST FLOW FROM OFF ATLANTIC ALONG WITH MVFR CEILINGS AT KLYH AND KDAN. UPSLOPING WESTERLY MOIST FLOW ALSO RESULTING IN MVFR RESTRICTIONS AT KBLF. THESE CONDITIONS ARE LIKELY TO PERSIST FOR THE REST OF THE NIGHT...BUT SHOULD GRADUALLY MIX BACK OUT TO VFR WITH UNRESTRICTED CONDITIONS BY MID TO LATE MORNING AS STRONG INSOLATION HELPS TO MIX UP/OUT INVERSION LAYER. ELSEWHERE AT KROA AND KBCB...MAINLY VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD. HOWEVER...SOME PATCHY FOG WITH LOCALIZED IFR TO EVEN LIFR RESTRICTIONS IS POSSIBLE IN SOME OF THE MOUNTAIN VALLEYS UNTIL SHORTLY AFTER DAYBREAK SUNDAY...AND THIS THREAT CONTINUES TO BE REFLECTED IN CLIMATOLOGICALLY FAVORED LOCATIONS... SUCH AS AT/NEAR KLWB. APPROACH OF NEXT UPSTREAM WEATHER SYSTEM AND ASSOCIATED COOL FRONT MAY BRING A THREAT FOR SCATTERED SHOWERS/THUNDERSTORMS TONIGHT (SUNDAY NIGHT)...ALONG WITH POSSIBLE RESTRICTIONS BACK INTO MVFR RANGE...ESPECIALLY IN THE MOUNTAINS. THIS FRONT IS EXPECTED TO STALL OVER/ALONG THE MID APPALACHIANS ON/BY MONDAY. ADDITIONAL WEAK SHORT WAVES AND MOISTURE STREAMING NORTHEAST OVER THE STALLED FRONT...COMBINING WITH AN EASTERLY FLOW FROM OFF THE ATLANTIC...MAY SET THE STAGE FOR ADDITIONAL MVFR WEATHER...POTENTIALLY LOWER...INTO THE MID WEEK PERIOD...ESPECIALLY OVER THE MOUNTAINS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/NF NEAR TERM...AMS/NF SHORT TERM...PH LONG TERM...PH AVIATION...WERT
AREA FORECAST DISCUSSION
NWS SEATTLE WA
930 PM PDT SAT MAR 31 2012 .SYNOPSIS...A LOW PRESSURE SYSTEM WILL MOVE THROUGH WESTERN WASHINGTON THIS EVENING AND INLAND LATER TONIGHT. STRONG ONSHORE FLOW WILL DEVELOP LATER TONIGHT AND PERSIST THROUGH SUNDAY MORNING. A STRONG CONVERGENCE ZONE MAY GIVE HEAVY SNOW FOR THE CENTRAL CASCADES SUNDAY MORNING. A WARM FRONT WILL REACH THE AREA SUNDAY NIGHT. A STRONG WET FRONTAL SYSTEM COULD DIRECT HEAVY RAIN INTO THE OLYMPIC MOUNTAINS MONDAY AND MONDAY NIGHT. THE SECOND HALF OF THE WEEK WILL BE COOL WITH JUST SCATTERED SHOWERS. && .SHORT TERM...AT 9PM LOW PRES EXTENDS ALONG THE WA AND NRN HALF OF THE ORE COAST...THE LOW WILL SHIFT INLAND WITH STRONG ONSHORE FLOW DEVELOPING OVERNIGHT. IT WILL BE BLUSTERY LATER TONIGHT THRU SUNDAY MORNING...ALTHOUGH BECAUSE A PSCZ SETS UP OVER SEATTLE ON THE UW WRFGFS I BELIEVE THE SSW WIND THROUGH THE PUGET SOUND BASIN SHOULD NOT BE ALL THAT STRONG AS IT MIGHT IF THE GRADIENTS FROM THE RUC OR NAM SLP FCSTS VERIFY. SHOWERS ARE INCREASING THIS EVENING...AND THERE WILL BE AN ADDITIONAL BURST OF HEAVIER SHOWERS AT THE LEADING EDGE OF THE STRONG ONSHORE FLOW...ESPECIALLY THROUGH THE STRAIT AND OVER THE NW INTERIOR LATE TONIGHT AS DEPICTED IN THE UW MM5NAM...OR OVER SW WA AND THEN THE CENTRAL CASCADES AS THE WRFGFS DEPICTS. OVERALL THE BEST BET FOR HEAVY PRECIP WILL BE OVER THE CENTRAL CASCADES FROM ABOUT 3AM TO 9AM WITH THE PSCZ...AND I THINK THE SNOWFALL FORECAST FOR STEVENS AND SNOQUALMIE SHOULD PROBABLY BE SOMETHING LIKE 6-12 INCHES SUNDAY MORNING SO WE MAY NEED A SNOW ADVISORY FOR THE MAIN PASSES SUN MORNING. SHOWERS WILL LIKELY TAPER OFF LATER SUN MORNING BEFORE INCREASING AGAIN LATE IN THE AFTERNOON AND EVENING AS THE DISTURBANCE WHICH IS NEAR 137W AT 9PM REACHES WRN WA...WITH PRETTY STRONG WLY FLOW IN THE MID LEVELS AND STRONG JETSTREAM. THAT SYSTEM IS QUICKLY OVERTAKEN BY MOISTURE FROM THE NEXT FRONTAL SYSTEM AND THE WARM ADVECTION MERGES WITH IT OVER WRN WA SUN NITE. AFTER THAT THE STRONG WLY FLOW BUCKLES AND BACKS TO SSW AS THE NEXT UPPER TROUGH ARRIVES JUST OFFSHORE. THIS SYSTEM WHICH AFFECTS WRN WA ON MONDAY IS THE FRONTAL SYSTEM CURRENTLY OUT AT 155W THIS EVENING WHICH DEVELOPS VERY RAPIDLY TONIGHT WITH A DEEP LOW WHICH HAPPENS GO FROM A 998MB CENTER THIS EVENING IN THE GFS TO A 968MB CENTER APPROACHING THE CHARLOTTES BY 12Z MON. PRECIP AMOUNTS IN THE MODELS VARY. THE GFS HAS THE HEAVY RAIN GOING INTO VANCOUVER ISLAND...THE NAM ON THE OTHER HAND SHOWS 36HR PCPN OF 3-9 INCHES OVER THE OLYMPICS WHICH WOULD GIVE RIVER FLOODING FOR PROBABLY THE SATSOP AND SKOKOMISH. ALSO SEE HYDRO DISCUSSION BELOW. 19 .LONG TERM...A COOL UPPER LEVEL TROUGH WILL BE OVER THE PAC NW FOR THE SECOND HALF OF THE WEEK. THAT WILL KEEP A CHANCE OF SHOWERS IN THE FCST BUT IT WILL BE PARTLY SUNNY MOST DAYS...TEMPS WILL STAY BELOW NORMAL. THIS WILL BE A GOOD PATTERN FOR SOME LATE SEASON SKIING AND A VITAMIN D RECHARGE. 19 && .HYDROLOGY...A WET FRONTAL SYSTEM IS ON TAP FOR MON AND MONDAY NIGHT...WITH HEAVY RAIN LIKELY FOR THE OLYMPICS. THE LATEST NAM SHOWS THE CASCADES GET MUCH LESS RAIN THAN THE OLYMPICS AND RIVERS FLOWING OUT OF THE CASCADES WOULD SEE PRETTY MODEST RISES...WITH WET SNOW ABOVE ABOUT 4KFT IN THE CASCADES LIKELY. THE OLYMPICS ON THE OTHER HAND REALLY GET HIT BY THE NAM WITH 3-9 INCHES OF RAIN IN 36HRS. THE 18Z GFS HAD A MAX OF 3-6.5 INCHES...BUT THE 00Z SOLUTION PUTS ALL THE HEAVY RAIN OVER VANCOUVER ISLAND WITH JUST AN INCH OR TWO FOR THE OLYMPICS. BEST BET NOW IS FLOODING POSSIBLE FOR A FEW OLYMPIC RIVERS BUT NO SOLUTIONS SUGGEST PROBLEMS FOR CASCADE RIVERS. 19 && .AVIATION...SOUTHWESTERLY FLOW ALOFT BECOMING WESTERLY ON SUNDAY. ELONGATED SURFACE LOW OVER WESTERN WASHINGTON WILL MOVE EAST OVERNIGHT. AIR MASS UNSTABLE WITH A LARGE AREA OF SHOWERS ASSOCIATED WITH THE LOW. CEILINGS LOWERING OVERNIGHT BACK DOWN TO THE 2000-3000 FOOT RANGE WITH THE INCREASING SHOWERS. AS THE SURFACE LOW MOVES EAST OF THE CASCADES AND HIGH PRESSURE BUILDS ALONG THE COAST STRONG ONSHORE FLOW WILL DEVELOP SUNDAY MORNING. THIS WILL GENERALLY KEEP CEILINGS IN THE 2000-3000 FOOT RANGE. A SHORTWAVE TROUGH MOVING QUICKLY IN THE JET STREAM SHOULD ENHANCE SHOWERS OVER THE AREA AGAIN SUNDAY AFTERNOON KEEPING AT LEAST AREAS OF CEILINGS IN THE 2000-3000 FOOT RANGE. SOME IMPROVEMENT LATE SUNDAY AFTERNOON INTO SUNDAY EVENING ESPECIALLY OVER THE CENTRAL PUGET SOUND WITH THE INCREASING WESTERLY FLOW ALOFT. KSEA...LIGHT WIND BECOMING SOUTHERLY 4 TO 8 KNOTS AFTER 09Z. SOUTHERLY WINDS INCREASING QUICKLY AROUND 15Z TO THE 15 GUST 25 KNOT RANGE. WINDS EASING IN THE AFTERNOON. CEILINGS BOUNCING AROUND WITH THE SHOWER ACTIVITY WITH MVFR CEILINGS A MAJORITY OF THE TIME ESPECIALLY AFTER 12Z. FELTON && .MARINE...ELONGATED SURFACE LOW OVER THE INTERIOR OF WESTERN WESTERN SHIFTING EAST OF THE CASCADES OVERNIGHT. STRONG SOUTHWEST ONSHORE PUSH DEVELOPS SUNDAY MORNING...WITH GALES LIKELY FOR THE FIRST HALF OF THE DAY FOR THE CENTRAL/EAST ENTRANCE AND HIGHER END SCA LEVEL WINDS OVER OTHER WATERS. GRADIENTS WILL BRIEFLY EASE SUNDAY AFTERNOON AS AN UPPER LEVEL DISTURBANCE SLIDING OVER SOUTHERN WASHINGTON IN THE AFTERNOON HELPS TO DECREASE ONSHORE GRADIENTS. A STRONG FRONTAL SYSTEM IS PEGGED TO REACH THE AREA ON MONDAY. 00Z GFS MODEL STILL SHOWS WARM FRONT LIFTING OVER THE AREA SUNDAY NIGHT...WITH INCREASINGLY S-SE WINDS OVER THE COAST AND USUAL INTERIOR ZONES. GALE WATCH WILL REMAIN IN EFFECT FOR THE COASTAL WATERS...NORTHERN INLAND WATERS...AND EAST ENTRANCE. FELTON && .SEW WATCHES/WARNINGS/ADVISORIES... WA...FLOOD ADVISORY REMAINS IN EFFECT FOR THE CHEHALIS RIVER NEAR GRAND MOUND IN THURSTON COUNTY. PZ...GALE WARNING IN EFFECT FROM 2 AM TO 5 PM PDT SUNDAY FOR THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE COASTAL WATERS...WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA... NORTHERN INLAND WATERS...ADMIRALTY INLET...AND PUGET SOUND/ HOOD CANAL. SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 11 PM PDT SUNDAY FOR THE GRAYS HARBOR BAR. GALE WATCH IN EFFECT FROM SUNDAY EVENING THROUGH MONDAY EVENING FOR THE COASTAL WATERS...ADMIRALTY INLET... ENTRANCES TO THE STRAIT OF JUAN DE FUCA...AND NORTHERN INLAND WATERS. && $$ WWW.WEATHER.GOV/SEATTLE FOR THE GRAPHICAL AFD VISIT... WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
325 AM CDT SUN APR 1 2012 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT 325 AM CDT SUN APR 1 2012 MAIN FORECAST CONCERNS ARE ON STRATUS TRENDS TODAY...AS WELL AS PRECIPITATION CHANCES TONIGHT THROUGH MONDAY NIGHT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING ALONG THE WEST COAST OF THE U.S....BUILDING RIDGING DOWNSTREAM ACROSS THE PLAINS INTO MANITOBA...AND TROUGHING OVER SOUTHEAST CANADA. WITHIN THIS LATTER TROUGHING...A STRONG SHORTWAVE WAS DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO. WITH THE BUILDING RIDGING/HEIGHTS AT 500MB TAKING PLACE NEAR AND WEST OF THE FORECAST AREA...A WARM ADVECTION PATTERN IS IN PLACE. SOUNDINGS AT GRB AND MPX REFLECT THIS...SHOWING 850MB TEMPS THAT ROSE TO 9C AT 15C RESPECTIVELY AT 00Z...COMPARED TO -2C AND 9C AT 12Z YESTERDAY. THE WARM ADVECTION OCCURRING ALOFT WAS A PROBLEM GETTING RID OF THE STRATUS DURING THE DAY YESTERDAY...PLUS THE DEPTH OF THE STRATUS AT 12Z WAS 75MB...BOTH MAKING IT TOUGHER TO MIX OUT. DURING THE EVENING...INCREASING 925MB WINDS OF 30-40KT HELPED TO BRING DRIER AIR BELOW 900MB SEEN ON THE 00Z DVN SOUNDING NORTHWARD...WHICH HAS CLEARED OUT THE LOW CLOUDS UP TO A FARIBAULT MN TO OSHKOSH WI LINE. SEEING SOME FOG DEVELOP IN THE CLEARING AREA. ACROSS NORTHERN WISCONSIN...925MB WINDS HAVE TURNED NORTHWEST...IN THE WAKE OF A COLD FRONT ABOVE THE SURFACE ASSOCIATED WITH THAT NORTHERN ONTARIO SHORTWAVE. BACK FARTHER TO THE SOUTH...CONVECTION ROLLED EAST ACROSS FAR SOUTHERN WISCONSIN...EASTERN IOWA INTO NORTHERN ILLINOIS OVERNIGHT...ON THE NOSE OF A LOW LEVEL JET AND SURFACE WARM FRONT WHICH SITS NOW NEAR I-80. TODAY AND TONIGHT...UPPER RIDGING SEEN BUILDING OVER THE PLAINS WILL SHIFT EAST THROUGH TONIGHT WITH THE AXIS RIGHT OVER THE FORECAST AREA AT 12Z. WITH THE UPPER FLOW GAINING A LITTLE MORE AMPLITUDE...THAT COLD FRONT SEEN IN 925MB PROFILER/VWP DATA LOOKS TO DROP SOUTH THROUGH MUCH OF THE FORECAST AREA BETWEEN 12-18Z. THE FRONT THEN STALLS OUT FOR THE AFTERNOON FROM SOUTHWEST MINNESOTA INTO NORTHERN ILLINOIS. WITH THE 925MB WINDS VEERING NORTHEASTERLY THEN SOUTHEASTERLY BEHIND THIS FRONT...THE STRATUS WILL MAKE ITS WAY BACK SOUTH ACROSS WISCONSIN PORTIONS OF THE FORECAST AREA. QUESTION THEN BECOMES FOR THE AFTERNOON...DOES THE STRATUS MIX OUT? FOR YESTERDAY...THE 31.00Z NAM AND 31.00-07Z RUC MODELS...AS WELL AS THE HRRR...WERE ALL SAYING THE STRATUS WOULD MIX OUT BY 19Z. SEEING THE SAME THING FROM THESE MODELS TODAY. ONE ADVANTAGE TO CLEARING IS THAT DRIER AIR IS LOWER IN THE ATMOSPHERE COMPARED TO THIS TIME YESTERDAY...NOTED BETWEEN THE 12Z AND 00Z GRB SOUNDING. THIS DRIER AIR LOOKS TO CONTINUE TO SINK TOWARDS THE SURFACE TODAY WHILE MIXING OCCURS. THE COMBINATION OF THE TWO SHOULD BE ABLE TO SCOUR OUT THE STRATUS. WITH THE STRATUS CONCERNS...HAVE LOWERED TEMPERATURES CLOSER TO THE NAM12 AND REGIONAL CANADIAN 2 METER OUTPUT...WHICH SEEMS REASONABLE. CERTAINLY IF CLOUDS STICK AROUND LONGER LIKE YESTERDAY...THESE STILL MAY BE TOO HIGH. HOWEVER...DO NOT WANT TO DROP TOO MUCH GIVEN ANY SUN AND 850MB TEMPS OF 12-16C COULD EASILY JUMP TEMPERATURES WELL INTO THE 70S. TONIGHT...THE LINGERING MOISTURE COULD REDEVELOP OR EXPAND INTO A STRATUS DECK WEST OF THE MISSISSIPPI RIVER AS THE 925MB WINDS INCREASE OUT OF THE SOUTHEAST. THE INCREASING WINDS ARE IN RESPONSE TO DEEPENING LOW PRESSURE OVER NEBRASKA WITH AN INVERTED TROUGH EXTENDING NORTHEAST THROUGH WESTERN MINNESOTA. SHOULD SEE A SURGE OF ISENTROPIC LIFT WITH THIS SYSTEM AS WELL...WHICH SHOWS UP WELL ON 305K SURFACES IN THE 06-12Z MONDAY TIME PERIOD FROM LA CROSSE SOUTHWESTWARD. SOUNDINGS CONTINUE TO SUGGEST A CAPPING INVERSION AT 750MB TO PREVENT ACCAS THAT DEVELOPS FROM THE LIFT INTO BECOMING DEEP CONVECTION. WILL CONTINUE THE DRY FORECAST...BUT MONITORING OF THIS CAP IS NEEDED. FURTHER NORTH... MODELS WERE SUGGESTING BEFORE CONVECTION POSSIBLY INTO TAYLOR COUNTY. THIS IS NOW PROGGED TO STAY WELL OFF TO THE NORTHWEST...UP NEAR DULUTH. THEREFORE HAVE PULLED THE 20 PERCENT CHANCES. MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGE OVER THE FORECAST AREA IS PROGGED TO SLOWLY FALL APART...IN RESPONSE TO THE NORTHERN PORTION OF THE CURRENT WESTERN TROUGH CROSSING FROM THE NORTHERN PLAINS THROUGH THE WESTERN GREAT LAKES. THE TIMING OF THE NORTHERN FEATURE CONTINUES TO BE A PROBLEM...WITH THE ECMWF/UKMET/CANADIAN CONSISTENTLY REMAINING SLOWER THAN THE NAM/GFS. THIS HAS SIGNIFICANT IMPLICATIONS ON TEMPERATURES AND ANY PRECIP TIMING. TRENDS IN THE NAM/GFS SINCE THE 31.00Z RUNS HAVE SHOWN SOME SLOWING...THEREFORE HAVE BIASED THE FORECAST TOWARDS THE SLOWER ECMWF/UKMET/CANADIAN. ALL MODELS ARE SUGGESTING A DRIER FORECAST MONDAY...ESPECIALLY DURING THE MORNING...AS ALL SYNOPTIC FORCING IS EITHER ACROSS NORTHERN MINNESOTA OR BACK IN THE FRONTOGENETIC AREA BEHIND THE INVERTED TROUGH CROSSING MINNESOTA. HAVE REDUCED PRECIPITATION CHANCES SOME FOR MONDAY AND LATER FORECASTS MAY BE ABLE TO COMPLETELY DRY IT OUT. WITH THE TRACK OF THE UPPER TROUGH...BEST DPVA FORCING SHOULD CONTINUE TO STAY MORE TOWARDS THE NORTH FOR MONDAY NIGHT. AS SUCH...WHEN YOU LOOK AT MODEL QPF FIELDS...MOST OF THE QPF ENDS UP NORTH OF I-94. PLUS...500MB HEIGHT FALLS ARE ONLY 10-20 METERS TOPS FROM I-90 SOUTH. THEREFORE...REDUCED MONDAY NIGHTS CHANCES ABOUT 10 PERCENT SOUTH OF I-90 AND KEPT 50 CHANCES GOING NORTH OF I-94. SPC CONTINUES TO SHOW A 5% CHANCE OF SEVERE WEATHER FOR MONDAY AND MONDAY NIGHT...BUT CONFIDENCE IS REALLY LOW WITH PRECIPITATION IN THE FIRST PLACE SEEING MODEL TRENDS TOWARDS DRIER OVERALL. INVERTED TROUGH SHOULD HAVE PUSHED THROUGH THE AREA MONDAY NIGHT...ALLOWING A COOLER...DRIER AREA OF HIGH PRESSURE TO BUILD IN FOR TUESDAY AND TUESDAY NIGHT. PREVIOUS FORECAST OF DRY CONDITIONS FOR THIS TIME PERIOD STILL LOOKS GOOD...AS WELL AS THE TEMPERATURES. REGARDING TEMPERATURES MONDAY AND MONDAY NIGHT...THESE ARE TRICKY AS ALREADY MENTIONED TIMING OF THE TROUGH IS CRITICAL. THERE COULD ALSO BE SOME STRATUS AND/OR ACCAS TO DEAL WITH MONDAY. LASTLY...THE WIND FLOW MONDAY IS STILL EAST TO SOUTHEAST. ON THE OTHER HAND...850MB TEMPS ARE 12-16C. FOR NOW COOLED HIGHS ACROSS WISCONSIN WITH MORE CLOUDS AND CLOSER TO EASTERLY FLOW. LOCATIONS LIKE OELWEIN AND CHARLES CITY COULD HIT 80...THOUGH. .LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT 325 AM CDT SUN APR 1 2012 01.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES REMAIN IN GOOD AGREEMENT OF AN OMEGA BLOCK PATTERN OVER CANADA AND THE U.S. FOR WEDNESDAY THROUGH FRIDAY...THEN BEGINS TO BREAK DOWN HEADING INTO THE WEEKEND. THE FORECAST AREA LIES EAST OF THE RIDGE AXIS IN THE OMEGA BLOCK... WHICH IS IN THE DAKOTAS AND MINNESOTA THROUGH EARLY FRIDAY. THIS FAVORS A RIDGE OF HIGH PRESSURE AT THE SURFACE WITH A COOL/DRY AIR FEED OUT OF CANADA. STILL...TEMPERATURES LOOK LIKE THEY SHOULD END UP A BIT ABOVE NORMAL. MAY HAVE TO DEAL WITH FROST FOR A FEW NIGHTS...THOUGH. SOME WARMING SHOULD OCCUR ON FRIDAY AS THE UPPER RIDGE AXIS MOVES IN AND THE SURFACE RIDGE MOVES EAST... ALLOWING A SOUTHERLY RETURN FLOW TO DEVELOP. FOR THE WEEKEND...TROUGHING OVER THE WESTERN U.S. IS EXPECTED TO EJECT OUT INTO THE NORTHERN PLAINS...BRINGING A COLD FRONT INTO OR THROUGH THE FORECAST AREA SATURDAY NIGHT. ENVISION THE WEEKEND TIMING OF ALL THIS WILL GET ADJUSTED OVER THE COMING DAYS...AND HAVE SOME CONCERN THE MAJORITY OF MODELS INCLUDING THE 01.00Z ECMWF ARE TOO FAST WITH THIS TIMING GIVEN THE DOWNSTREAM RIDGE. THEREFORE...PRECIPITATION CHANCES WITH THE WARM CONVEYOR BELT AHEAD OF THE COLD FRONT ARE HELD TO 20-30 AT THIS TIME. DID NOT INTRODUCE ANY THUNDER BECAUSE THERE APPEARS TO BE LIMITED INSTABILITY AT THIS TIME. TEMPERATURES SHOULD STAY ABOVE NORMAL FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT...UNTIL THE COLD FRONT PASSES. EVEN BEHIND IT...READINGS COULD STAY NEAR OR ABOVE NORMAL. && .AVIATION...THROUGH 06Z MONDAY 1150 PM CDT SAT MAR 31 2012 CHALLENGING CLOUD FORECAST ONCE AGAIN FOR THIS SET OF TAFS. 925MB WINDS HAVE BECOME MORE SOUTHERLY THROUGH THE EVENING HOURS WHICH HAS PUSHED THE LOW STRATUS NORTH OF THE TAF SITES. 01.00Z HRRR DOES SHOW THIS NORTHWARD TREND THROUGHOUT THE NIGHT...BEFORE EXPANDING IT BACK SOUTHWARD BETWEEN 11Z-14Z. THE BIGGEST QUESTION IS WILL THEY MAKE IT BACK IN TO KLSE AND KRST. BOTH THE 01.00Z RUC AND NAM SHOWS THESE LOW LEVEL WINDS TO BECOME MORE EASTERLY BY 12Z WHICH WOULD TEND TO FAVOR THE CLOUDS MOVING BACK SOUTHWARD OR RE-DEVELOPING. FOR THE 06Z TAFS...DID BRING THE STRATUS BACK IN AT BOTH SITES BETWEEN 13Z-19Z...ALONG WITH SOME REDUCED VISIBILITIES. COULD BE SOME IFR CONDITIONS...ESPECIALLY AT KRST. STILL EXPECT THESE TO SCATTERED OUT MIDDAY TO EARLY AFTERNOON SUNDAY AS STRONGER PRESSURE GRADIENT INCREASES THE WINDS. VFR CONDITIONS THEN WILL PERSIST THROUGH 06Z. && .ARX WATCHES/WARNINGS/ADVISORIES... 325 AM CDT SUN APR 1 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS ALBANY NY
1038 AM EDT SUN APR 1 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES AND ACROSS THE REGION THIS AFTERNOON INTO TONIGHT...ALLOWING FOR SOME RAIN SHOWERS. SOME WET SNOW MAY MIX IN WITH THE RAIN SHOWERS ACROSS THE HIGHEST TERRAIN TONIGHT. HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION PROVIDING FAIR WEATHER FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... LATEST VISIBLE SATELLITE IMAGERY SHOWS THAT LOWER STRATUS CLOUDS HAVE COMPLETELY OVERTAKEN THE CWA. MEANWHILE...THE 12 UTC KALY SOUNDING SHOWS ENOUGH DRY AIR IN PLACE FOR THE BOTTOM FEW THOUSAND FEET OF THE COLUMN...AND BUFR MODEL SOUNDING SUPPORT THIS HOLDING FOR A FEW HOURS AS WELL. THE LATEST REGIONAL RADAR IMAGERY CONTINUES TO SHOW NO RETURNS ACROSS OUR AREA...BUT INCREASING AMOUNTS OF LIGHT TO MODERATE PRECIP ACROSS WESTERN NY/LAKE ONTARIO DUE TO A SHORTWAVE AND WEAK SURFACE LOW ACROSS THE GREAT LAKES. FOR NOW...WILL CONTINUE TO FORECAST CLOUDY...BUT DRY WEATHER FOR MUCH OF THE AREA THROUGH AROUND NOON. FOR THE AFTERNOON HOURS...WILL STEADILY INCREASE POPS TO CATEGORICAL FOR MOST AREAS BY THE LATE AFTN HOURS. THE NEW 12 UTC NAM AND 10 UTC 3KM HRRR ALL SHOW BATCHES OF LIGHT RAIN SHOWERS MOVING ACROSS THE AREA FROM NORTHWEST TO SOUTHEAST THROUGH THE AFTN AND EVENING HOURS...WITH THE BEST QPF ACROSS THE CATSKILLS...AS THE LOW PRESSURE WAVE MOVES ACROSS OUR AREA. ALTOUGH QPF SHOULD BE FAIRLY LIGHT...ALL AREAS SEEM TO AT LEAST GET A FEW HUNDREDTHS...SO HIGH LIKELY/CATEGORICAL POPS SEEM WARRANTED. MAX TEMPS TODAY WILL PROBABLY BE IN THE EARLY AFTN JUST BEFORE THE START OF PRECIP...WITH TEMPS RANGING FROM THE UPPER 30S ACROSS THE SRN DACKS TO NEAR 50 IN THE MID HUDSON VALLEY. AFTER 00 UTC...WILL START TO LOWER POPS FROM NORTHWEST TO SOUTHEAST...AS MODEL GUIDANCES SHOWS THE BEST FORCING AND ASSOCIATED PRECIPITATION DROPPING SOUTHEAST OF THE REGION. AT THE HIGHEST TERRAIN /GENERALLY 2500 FT AND ABOVE/...ANY LINGERING RAIN SHOWERS COULD START TO MIX WITH OR CHANGE OVER TO SNOW SHOWERS AS TEMPS ALOFT START TO CRASH. ANY SNOW ACCUMULATION LOOKS VERY LIGHT...OF ABOUT A HALF INCH OR SO...AND MAINLY LIMITED TO THE HIGH PEAKS OF THE CATSKILLS AND HIGHEST ELEVATIONS IN SOUTHERN VERMONT. A COATING OF SNOW IS POSSIBLE ACROSS THE SOUTHERN ADIRONDACKS AS WELL. VALLEY AREAS WILL PROBABLY JUST STAY AS RAIN SHOWERS BEFORE ENDING AND NO SNOW ACCUMULATION IS EXPECTED IN ANY VALLEY AREAS AT THIS TIME. ANY PRECIP SHOULD BE FINISHED BY AROUND 06 UTC...WITH CLEARING TAKING PLACE FOR THE REMAINDER OF THE NIGHT...AS SKIES BECOME PARTLY CLOUDY. THIS SHOULD ALLOW TEMPS TO FALL OFF...WITH MIN TEMPS RANGING FROM THE 20S IN THE DACKS TO THE MID 30S IN THE CAPITAL REGION/MID HUDSON VALLEY. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... MONDAY INTO TUESDAY MODEL SUITE IS IN AGREEMENT OTHER THAN 6-9 HOURS DIFFERENCE IN TIMING OF TUES CDFNT AND INTENSITY OF 500HPA SHORT WAVES WED. FAST MOVING FLOW AT 500HPA OVER RGN...AS 500HPA TROF DEPARTS...RIDGE BUILDS EAST...ANOTHER SHORT WV FOLLOWS LATE TUESDAY. TUESDAY NIGHT SOME DIFFERENCES BEGIN TO EMERGE. AT SFC MASSIVE HIGH BUILDS FM HUDSONS BAY S INTO GRTLKS AS A SERIES OF STRONG 500HPA SHORT WVS DIVE SE ACROSS THE RGN. THE MODEL SUITE GENERALLY (GFS/GEM/12UTC ECMWF) ARE AGGRESSIVE WITH THE SHORT WAVES...THE NAM THE LEAST AND THE OUTLIER. THE MORE AGGRESSIVE SHORT WV SOLUTION RESULTS IN SOME INSTAB -SHRA/SN AT HIR TRRN...VRBL CLOUDS...BRISK N WINDS AND THIS SOLUTION IS THE ONE THE FCST WILL LEAN TWRD WITH NAM BEING THROWN OUT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... GFS AND ECMWF FAIRLY SIMILAR IN THIS PERIOD. 500HPA TROF OVER MARITIMES WILL SLOWLY DEPART...MASSIVE SFC HIGH FM HUDSONS BAY WILL BUILD INTO GRTLKS. FCA WILL BE BTWN THESE TWO SYSTEMS WITH GENERALLY DRY CONDS...SOME CLOUDS INTO FRI AS 500 HPA SHORT WAVES ROTATED ACROSS FCA. BY SAT SFC HIGH HAS MOVED INTO RGN. GFS SHIFTS 500HPA TROF OFFSHORE...ECMWF HAS CUTOFF FORM ALONG DELMARVA/SE COAST WHILE GFS KEEPS PROGRESSIVE TROFS MOVING OFFSHORE. ECMWF DEVELOPS POTENTIAL COASTAL SFC LOW THAT DRIFTS N WITH CUTOFF. THIS SYSTEM BACKS INTO FCA SUN WITH CLDS AN LT RN. FOR NOW WILL GO W/GMOS SOLUTION. SINCE ONLY DIFFERENCE IS IN DAYS 7-8. TEMPS WILL REMAIN NR NRMLS...REACHING 5 DEGREES ABV BY END OF PD. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS DESPITE THE EXPANDING STRATUS DECK ACROSS THE REGION. UPSTREAM SYSTEM APPROACHES DURING THE DAY WITH LOWER CIGS AND INCREASING CHANCES FOR WET CONDITIONS. THERE WILL BE A PERIOD LATER THIS AFTERNOON INTO EARLY EVENING WITH MVFR FLIGHT CONDITIONS. WINDS WILL BE LIGHT AND VARIABLE THIS EARLY SUNDAY MORNING. THOSE WINDS BECOME WEST-SOUTHWEST LATE THIS MORNING IN ADVANCE OF THIS SYSTEM AT SPEEDS LESS THAN 10KTS. WINDS QUICKLY SHIFT TO THE NORTH-NORTHWEST IN THE WAKE OF THIS STORM THIS EVENING AROUND 10 KTS AND CONTINUE OVERNIGHT. OUTLOOK... MON-TUE...VFR...NO SIG WX. TUE NT...MAINLY VFR...CHC -RA OR -SHRA. WED-THU...VFR...NO SIG WX. && .FIRE WEATHER... LOW PRESSURE DROPPING SOUTHEAST FROM THE GREAT LAKES WILL MOVE ACROSS THE REGION TODAY INTO THIS EVENING...THEN A MASSIVE HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION FOR EARLY NEXT WEEK. AS SHOWERS MOVE ACROSS THE REGION...RELATIVE HUMIDITY VALUES WILL GENERALLY REMAIN ABOVE 50 PERCENT. AS THIS SYSTEM DEPARTS TONIGHT...THE WET WEATHER ALSO SUBSIDES AS RELATIVE HUMIDITIES RANGE BETWEEN 80 AND 90 PERCENT. SURFACE WINDS WILL BE WEST-SOUTHWEST AT 5 TO 15 MPH TODAY...BECOMING NORTHERLY TONIGHT AT 10 MPH OR LESS...THEN INCREASING TOWARD SUNRISE AND THROUGH THE DAY MONDAY WITH GUSTS OVER 20 MPH. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS. THE ONLY PCPN EXPECTED IN THE NEXT WEEK WILL BE A QUARTER TO THIRD INCH TODAY...ISOLATED -SHRA LATE TUESDAY. OTHERWISE WILL BE DRY WITH TEMPS BLO NORMAL AT FIRST...RISING NEAR NORMAL MID WEEK AND ENDING THE WEEK ABV NORMALS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS NEAR TERM...FRUGIS SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...BGM FIRE WEATHER...BGM HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
634 AM EDT SUN APR 1 2012 .SYNOPSIS... LOW PRESSURE DROPPING SOUTHEAST FROM THE GREAT LAKES WILL MOVE ACROSS THE REGION TODAY. A LOBE OF HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION FROM HUDSON BAY MONDAY...AND SLIDE OFFSHORE TUESDAY. LATE TUESDAY A COLD FRONT DROP THROUGH THE REGION. WEDNESDAY THROUGH THE END OF THE WEEK...THE REST OF THE HUDSONS BAY HIGH PRESSURE AREA WILL BUILD INTO THE GREAT LAKES WHILE A STORM LINGERS IN THE MARITIMES. && .NEAR TERM /THROUGH TONIGHT/... STRATUS DECK EXPANDING SLOWLY THIS EARLY SUNDAY MORNING PER THE 11U-3.9U IMAGERY. MEANWHILE...AN INCREASE IN HIGH LEVEL MOISTURE WAS UNDERWAY FROM THE CLIPPER TYPE SYSTEM ACROSS THE NORTHERN GREAT LAKES REGION. PER THE SATELLITE DERIVED WINDS...THE UPPER JET WAS GREATER THAN 120KTS...SO A RATHER DYNAMIC SYSTEM. FORECAST BUFR PROFILES ALL SUGGEST THE LOW LEVEL DRY AIR WILL HANG ON TOUGH THROUGH MOST OF THE MORNING AND WILL CUT BACK POPS ACCORDINGLY. LATEST RUC13/HRRR DOES SUGGEST SHOWER ACTIVITY WILL DEVELOP AND BECOME ENHANCED WITH FAVORABLE UPSLOPE CONDITIONS THROUGH THE NOON HOUR AND INTO THE AFTERNOON AND WE WILL RAISE POPS INTO THE LIKELY CATEGORY. LATEST HRRR CONTINUES ALONG THIS FORECAST LINE THIS SUNDAY MORNING. THERMAL PROFILES ARE CHILLY YET THOSE BOUNDARY LAYER VALUES ARE EXPECTED TO REMAIN RATHER MILD TODAY. THE FREEZING LEVEL FORECASTS FROM THE NCEP MODEL SUITE SUGGEST FOR SNOW LEVELS WILL BE RATHER HIGH...AT OR ABOVE 2K FEET. SO FOR MOST OF THE REGION...EXPECTATIONS ARE FOR MAINLY RAIN/RAIN SHOWERS TODAY UNDER CLOUDY SKIES. WE WILL SHADE A LITTLE CLOSER TO THE COOLER SIDE OF THE GUIDANCE ENVELOPE WHICH IS IN LINE WITH THE LATEST LAV/LAMP. PRECIP WILL END FROM NORTHWEST TO SOUTHEAST THIS EVENING WITH THE QUICK DEPARTURE OF THIS SYSTEM. SOME UPSLOPE CLOUD ENHANCEMENT...ESPECIALLY FOR OUR ADJACENT WESTERN NEW ENGLAND COUNTIES...ARE EXPECTED BUT WE WILL DIMINISH THOSE POPS ACCORDINGLY. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... MONDAY INTO TUESDAY MODEL SUITE IS IN AGREEMENT OTHER THAN 6-9 HOURS DIFFERENCE IN TIMING OF TUES CDFNT AND INTENSITY OF 500HPA SHORT WAVES WED. FAST MOVING FLOW AT 500HPA OVER RGN...AS 500HPA TROF DEPARTS...RIDGE BUILDS EAST...ANOTHER SHORT WV FOLLOWS LATE TUESDAY. TUESDAY NIGHT SOME DIFFERENCES BEGIN TO EMERGE. AT SFC MASSIVE HIGH BUILDS FM HUDSONS BAY S INTO GRTLKS AS A SERIES OF STRONG 500HPA SHORT WVS DIVE SE ACROSS THE RGN. THE MODEL SUITE GENERALLY (GFS/GEM/12UTC ECMWF) ARE AGGRESSIVE WITH THE SHORT WAVES...THE NAM THE LEAST AND THE OUTLIER. THE MORE AGGRESSIVE SHORT WV SOLUTION RESULTS IN SOME INSTAB -SHRA/SN AT HIR TRRN...VRBL CLOUDS...BRISK N WINDS AND THIS SOLUTION IS THE ONE THE FCST WILL LEAN TWRD WITH NAM BEING THROWN OUT. && .LONG TERM /THURSDAY THROUGH SATURDAY/... GFS AND ECMWF FAIRLY SIMILAR IN THIS PERIOD. 500HPA TROF OVER MARITIMES WILL SLOWLY DEPART...MASSIVE SFC HIGH FM HUDSONS BAY WILL BUILD INTO GRTLKS. FCA WILL BE BTWN THESE TWO SYSTEMS WITH GENERALLY DRY CONDS...SOME CLOUDS INTO FRI AS 500 HPA SHORT WAVES ROTATED ACROSS FCA. BY SAT SFC HIGH HAS MOVED INTO RGN. GFS SHIFTS 500HPA TROF OFFSHORE...ECMWF HAS CUTOFF FORM ALONG DELMARVA/SE COAST WHILE GFS KEEPS PROGRESSIVE TROFS MOVING OFFSHORE. ECMWF DEVELOPS POTENTIAL COASTAL SFC LOW THAT DRIFTS N WITH CUTOFF. THIS SYSTEM BACKS INTO FCA SUN WITH CLDS AN LT RN. FOR NOW WILL GO W/GMOS SOLUTION. SINCE ONLY DIFFERENCE IS IN DAYS 7-8. TEMPS WILL REMAIN NR NRMLS...REACHING 5 DEGREES ABV BY END OF PD. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS DESPITE THE EXPANDING STRATUS DECK ACROSS THE REGION. UPSTREAM SYSTEM APPROACHES DURING THE DAY WITH LOWER CIGS AND INCREASING CHANCES FOR WET CONDITIONS. THERE WILL BE A PERIOD LATER THIS AFTERNOON INTO EARLY EVENING WITH MVFR FLIGHT CONDITIONS. WINDS WILL BE LIGHT AND VARIABLE THIS EARLY SUNDAY MORNING. THOSE WINDS BECOME WEST-SOUTHWEST LATE THIS MORNING IN ADVANCE OF THIS SYSTEM AT SPEEDS LESS THAN 10KTS. WINDS QUICKLY SHIFT TO THE NORTH-NORTHWEST IN THE WAKE OF THIS STORM THIS EVENING AROUND 10 KTS AND CONTINUE OVERNIGHT. OUTLOOK... MON-TUE...VFR...NO SIG WX. TUE NT...MAINLY VFR...CHC -RA OR -SHRA. WED-THU...VFR...NO SIG WX. && .FIRE WEATHER... LOW PRESSURE DROPPING SOUTHEAST FROM THE GREAT LAKES WILL MOVE ACROSS THE REGION TODAY INTO THIS EVENING...THEN A MASSIVE HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION FOR EARLY NEXT WEEK. AS SHOWERS MOVE ACROSS THE REGION...RELATIVE HUMIDITY VALUES WILL GENERALLY REMAIN ABOVE 50 PERCENT. AS THIS SYSTEM DEPARTS TONIGHT...THE WET WEATHER ALSO SUBSIDES AS RELATIVE HUMIDITIES RANGE BETWEEN 80 AND 90 PERCENT. SURFACE WINDS WILL BE WEST-SOUTHWEST AT 5 TO 15 MPH TODAY...BECOMING NORTHERLY TONIGHT AT 10 MPH OR LESS...THEN INCREASING TOWARD SUNRISE AND THROUGH THE DAY MONDAY WITH GUSTS OVER 20 MPH. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS. THE ONLY PCPN EXPECTED IN THE NEXT WEEK WILL BE A QUARTER TO THIRD INCH TODAY...ISOLATED -SHRA LATE TUESDAY. OTHERWISE WILL BE DRY WITH TEMPS BLO NORMAL AT FIRST...RISING NEAR NORMAL MID WEEK AND ENDING THE WEEK ABV NORMALS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...SNYDER NEAR TERM...BGM SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...BGM FIRE WEATHER...BGM HYDROLOGY...BGM WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1051 AM CDT SUN APR 1 2012 .DISCUSSION... ISSUED 1040 AM CDT SUN APR 1 2012 PRECIP ASSOCIATED WITH EXITING MCS WELL OFF TO THE EAST LEAVING SUNNY SKIES IN ITS WAKE. TEMPERATURES ARE QUICK TO REBOUND AS WELL...LENDING MORE CONFIDENCE TO THE WARM FORECAST. NEWEST NAM KEEPS AFTERNOON DRY...CONSIDERING THE RAPID RETREAT OF THE SHOWERS THIS MORNING...WILL KEEP ISL WORDING...AND NOT RAISE THE POP THIS AFTERNOON IN THE EAST. MINOR TWEAKS TO HRLY AND POP GRIDS. UPDATE OUT MOMENTARILY. HJS && .AVIATION... ISSUED 655 AM CDT SUN APR 1 2012...FOR THE 12Z TAFS THE ONLY LINGERING MVFR CONDITIONS ARE IN DEC WITH 5SM BR AT 1145Z. STORMS HAVE MOVE EAST OF CMI...AN NO PRECIP SHOULD AFFECT ANY OF THE TERMINALS FOR MOST OF THE DAY. ACTUALLY...ALL OUR TERMINALS SHOULD BE VFR FOR MOST OF THE NEXT 24 HOURS. FORECAST SOUNDINGS CONFIRM WHAT THE CU RULE IS INDICATING FOR VFR CLOUD REDEVELOPMENT THIS AFTERNOON. THOSE CLOUDS MAY REDUCE HIGH TEMPS A LITTLE, BUT IT WILL STILL BE A VERY WARM DAY. SOME LIGHT MVFR FOG MAY FORM AGAIN LATER TONIGHT...AS A BACK DOOR COLD FRONT DROPS SOUTH INTO CENTRAL IL FROM NORTHERN IL AND N INDIANA. THE PRIMARY FOCUS FOR PRECIP WILL BE IN THE EAST...FOR CMI AND POSSIBLY DEC. WE INTRODUCED A VCSH WITH CB IN CMI AFTER 10Z. WINDS WILL SHIFT FROM SOUTHEAST EARLY IN THE TAF PERIOD TO SOUTHWEST BY MID MORNING. WIND SPEEDS MAY REACH UP NEAR 20KT AT TIMES DURING PEAK MIXING OF LATE MORNING/EARLY AFTERNOON. AS THE COLD FRONT DROPS INTO C IL TONIGHT...WINDS WILL SHIFT EAST- SOUTHEAST AGAIN...REMAINING IN THE 10-13KT RANGE FOR MOST TERMINAL SITES. LIGHT MVFR FOG MAY REDEVELOP LATE TONIGHT...ESPECIALLY FOR OUR NORTHERN TAFS OF PIA/BMI/CMI. MVFR CLOUDS WILL BE POSSIBLE AS WELL. SHIMON && .PREV DISCUSSION... ISSUED 300 AM CDT SUN APR 1 2012 SMALL MCS FORMED AS EXPECTED OVER EASTERN IOWA LATE IN THE EVENING...AND HAS BEEN MOVING ACROSS THE NORTHERN CWA OVERNIGHT...PRODUCING SEVERE HAIL AT TIMES. HAVE SEEN SOME SHOWERS/STORMS AS FAR SOUTH AS LINCOLN AT 2 AM. SHORT TERM...TODAY THROUGH TUESDAY... LATEST HRRR MODEL...WHICH HAS A GOOD HANDLE ON THE ACTIVITY... SHOWS MUCH OF THE RAIN SHOULD LARGELY BE OUT OF THE CWA BY SUNRISE. WILL MAKE A LAST MINUTE DECISION ON HOW LONG TO LINGER IT THIS MORNING. ONCE THAT CLEARS OUT...TEMPERATURES BECOME THE PRIMARY FOCUS. STILL LOOKING FOR HIGHS IN THE 80S ACROSS THE ENTIRE AREA...CLOSE TO THE DAILY RECORDS. HOWEVER...EVENING MODEL RUNS SHOWING A FRONTAL BOUNDARY NEAR THE I-80 CORRIDOR WILL LIKELY SLIP A BIT SOUTHWARD THIS AFTERNOON...DRIVEN BY A RATHER STIFF NORTHEAST FLOW. IF IT SLIPS TOO FAR...THEN TEMPERATURES ACROSS THE NORTHEAST CWA MAY END UP BEING COOLER THAN EXPECTED. WRF MODEL OUT OF WFO CHICAGO HAS THE BOUNDARY ALMOST ALL THE WAY TO I-74 BY 6 PM. WILL NEED TO WATCH THIS CLOSELY DURING THE AFTERNOON. BOUNDARY WILL PROBABLY REACH AT LEAST INTO PART OF THE CWA THIS EVENING...BEFORE BEGINNING TO RETREAT. SAME PROBLEM EXISTS WITH TEMPERATURES MONDAY AFTERNOON...DUE TO ITS POSITION. HAVE PULLED HIGH TEMPERATURES DOWN A BIT NORTH OF I-74...BUT STILL GOING A FEW DEGREES ABOVE GUIDANCE IN THAT AREA. REMAINDER OF THE CWA MORE LIKELY TO REACH THE 85-90 DEGREE RANGE...AGAIN NEAR THE RECORDS. TIMING OF COLD FRONTAL PASSAGE TUESDAY MORNING APPEARS TO HAVE SLOWED A BIT FROM EARLIER RUNS...SO HAVE KEPT TEMPERATURES SOUTH OF I-70 WARMER THAN PREVIOUSLY FORECAST...WITH LOWER 80S. THREAT OF SHOWERS/STORMS TO CONTINUE INTO THE AFTERNOON WITH THE BOUNDARY IN THE AREA. LONG TERM...WEDNESDAY THROUGH SATURDAY... STILL LOOKING TO BE MUCH COOLER THAN THE START OF THE WEEK...ALTHOUGH STILL A BIT ABOVE NORMAL. FOCUS IN THIS PERIOD REMAINS WITH A CUTOFF LOW WHICH WILL DEVELOP OVER THE SOUTHERN ROCKIES EARLY IN THE WEEK. LONGER RANGE MODELS IN REASONABLE AGREEMENT WITH A TRACK THAT TAKES IT SOUTH OF THE OHIO VALLEY...BUT WILL STILL SEE THE RAIN SHIELD ON THE NORTHERN FLANK EXTEND WELL TO THE NORTH. HAVE CUT BACK ON THE RAIN ACROSS THE NORTHERN CWA FOR WEDNESDAY/THURSDAY... WITH THE PERSISTENT NORTHEAST FLOW BRINGING DRIER AIR INTO CENTRAL ILLINOIS. MAINLY DRY CONDITIONS EXPECTED LATE IN THE WEEK...AS A NARROW RIDGE OF HIGH PRESSURE MOVES INTO THE MISSISSIPPI VALLEY. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1005 AM CDT SUN APR 1 2012 .DISCUSSION... 1005 AM CDT THE EARLY MORNING STORMS HAVE MOVED QUICKLY SOUTHEAST INTO SOUTHERN INDIANA. IN THEIR WAKE...THEY HELPED TO SINK THE FRONTAL BOUNDARY SOUTH TO NEAR INTERSTATE 88 AT AROUND 10 AM. TO THE NORTH...WHERE STRATUS AND NORTHERLY WINDS PREVAIL...TEMPERATURES HAVE BEEN BASICALLY FLAT LINE. WHILE SOME MIXING OUT OF THE STRATUS MAY OCCUR LATE THIS MORNING...REINFORCING NORTHEAST COLD AIR ADVECTION WILL EVOLVE AS A WEAK LOW SHIFTS EAST ALONG THE FRONTAL BOUNDARY. THIS SCENARIO SHOULD ENABLE THE FRONT TO MOVE SOUTH KEEPING TEMPERATURES COOLER TO THE NORTH...WITH PLACES SEEING A FALL THIS AFTERNOON ESPECIALLY IN THE NEAR DOWNSTREAM OF LAKE MICHIGAN. THE 01.12 NAM CAPTURES THIS TREND WELL...AND SEEMS TO HAVE A DECENT HANDLE ON THE STRATUS EVOLUTION...HINTING AT LOW CLOUDS ALONG AND IMMEDIATELY BEHIND THE BOUNDARY THROUGH THIS AFTERNOON. IT IS A TALE OF TWO DIFFERENT DAYS ACROSS THE CWA AS TO THE SOUTH OF THE FRONT...TEMPERATURES ARE OFF TO THE RACES WITH MID 60S ALREADY AT 10 AM IN PERU AND PONTIAC. A WARM-UP TO AROUND OR JUST ABOVE 80 DEGREES STILL LOOKS WELL IN PLACE...ESPECIALLY SEEING GUSTS TO AROUND 20 KTS ALREADY INDICATING GOOD MIXING AND CONTINUED LOW- LEVEL WARM AIR ADVECTION. THE 12Z ILX RAOB HAD NEAR 1300 J/KG OF MUCAPE WHICH SHOULD BE A GOOD BASELINE FOR WHAT IS SHIFTING OVER THE SOUTHERN FORECAST AREA AS IT CONTINUES TO WARM. THIS LOOKS TO MAXIMIZE/POOL THIS AFTERNOON BETWEEN 1500 AND 2000 J/KG IN THE FAR SOUTH...BUT IN THE ABSENCE OF ANY PRONOUNCED TRIGGER AND A QUICKLY WEAKENING LOW- LEVEL JET. THE WEAK SURFACE CIRCULATION ALONG THE BOUNDARY MAY HELP TO INCREASE CONVERGENCE SOME AS IT SHIFTS EAST THROUGH THE AFTERNOON. ALSO...AN ILL- DEFINED SHORT WAVE RIPPLE IN EASTERN IA IS SHIFTING EAST. TOGETHER IT MIGHT BE ENOUGH TO SPARK ISOLATED THUNDERSTORMS...GENERALLY SOUTH OF U.S. HIGHWAY 24 THIS AFTERNOON. ABOUT ONE THIRD OF EXPLICIT CONVECTIVE GUIDANCE LOOKED AT HAS THAT FORM OF SOLUTION. INSTABILITY PROFILES ARE ENOUGH TO WARRANT MAINLY A HAIL THREAT IF ANY STORM WERE TO SUSTAIN ITSELF. MTF && .PREV DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * FOG WITH VIS OF 3-5SM THROUGH LATE MORNING...WITH CONDITIONS IMPROVING BY MID DAY. * POTENTIAL REMAINING FOR A PERIOD OF MVFR CEILINGS 1500-2000 FT LATE MORNING TO MID AFTERNOON. * NORTHEAST WINDS STEADILY INCREASING THROUGHOUT THE DAY...WITH SOME GUSTS POSSIBLE IN THE AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 12Z... EXPECT SOME RATHER VARIABLE CONDITIONS THROUGH EARLY AFTERNOON IN TERMS OF WINDS/CIGS/VSBY. CURRENTLY...SHRA/TSRA ACTIVITY ACROSS FAR NE IL IS MOVING INTO NW IN AND WILL EXIT TO THE EAST OF GYY TOWARD 14Z. NEXT CONCERNS ARE RELATED TO WEAK LOW PRESSURE WHICH WILL MOVE ALONG A FRONTAL BOUNDARY EXTENDING FROM NEAR KCID TO KRPJ TO JUST NORTH OF KPWK THIS MORNING. THIS FRONT IS EXPECTED TO SAG SOUTHWARD THROUGH THE MORNING BRINGING WINDS TO THE NORTHEAST ACROSS THE CHI AND NW IN TERMINALS...WITH RFD ALREADY SEEING NE WINDS. AS THE FRONT MOVES WINDS WILL LIKELY BECOME LIGHT AND VARIABLE WITH A SOUTH TO WEST DIRECTION. GIVEN THE RAINFALL THIS MORNING AND THE LIGHT WIND REGIME EXPECT THAT MVFR VSBY WILL PREVAIL...WITH SOME IFR TOWARDS DPA AND RFD...THROUGH AT LEAST MID MORNING AND POSSIBLY LONGER. IN ADDITION...FORECAST SOUNDINGS CONTINUE TO SHOW DEVELOPMENT OF MVFR LEVEL STRATUS DECK BY MIDDAY WHICH WOULD THEN SCATTER LATER THIS AFTERNOON. THIS SEEMS PLAUSIBLE GIVEN THE SHIFT TO A COOLER NORTHEASTERLY FLOW OFF THE LAKE AND THE ABUNDANT LOW LEVEL MOISTURE ALREADY IN PLACE. THERE IS A CHANCE THAT MIST/HAZE WILL CONTINUE THROUGH THE AFTERNOON AS WELL BUT CONFIDENCE IS LOW. NORTHEAST WINDS WILL TURN EASTERLY TONIGHT AS RIDGING BUILDS TO THE EAST AND LOW PRESSURE TAKES SHAPE ACROSS THE CENTRAL PLAINS. VFR SHOULD PREVAIL BUT SOME MVFR VSBY REDUCTION IS POSSIBLE LATE. WINDS WILL THEN TURN MORE SOUTHEASTERLY MONDAY MORNING. MDB //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM HIGH CONFIDENCE OF FOG/VIS TRENDS WITH MEDIUM CONFIDENCE OF TIMING IMPROVEMENT. * LOW MEDIUM CONFIDENCE OF A PERIOD OF 1500-2000 FT CEILINGS LATE MORNING INTO THIS AFTERNOON. * HIGH CONFIDENCE IN WIND SPEED AND DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH CHANCE TSRA. TUESDAY...VFR WITH CHANCE SHRA/TSRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. MDB && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
912 AM CDT SUN APR 1 2012 .DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * FOG WITH VIS OF 3-5SM THROUGH LATE MORNING...WITH CONDITIONS IMPROVING BY MID DAY. * POTENTIAL REMAINING FOR A PERIOD OF MVFR CEILINGS 1500-2000 FT LATE MORNING TO MID AFTERNOON. * NORTHEAST WINDS STEADILY INCREASING THROUGHOUT THE DAY...WITH SOME GUSTS POSSIBLE IN THE AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 12Z... EXPECT SOME RATHER VARIABLE CONDITIONS THROUGH EARLY AFTERNOON IN TERMS OF WINDS/CIGS/VSBY. CURRENTLY...SHRA/TSRA ACTIVITY ACROSS FAR NE IL IS MOVING INTO NW IN AND WILL EXIT TO THE EAST OF GYY TOWARD 14Z. NEXT CONCERNS ARE RELATED TO WEAK LOW PRESSURE WHICH WILL MOVE ALONG A FRONTAL BOUNDARY EXTENDING FROM NEAR KCID TO KRPJ TO JUST NORTH OF KPWK THIS MORNING. THIS FRONT IS EXPECTED TO SAG SOUTHWARD THROUGH THE MORNING BRINGING WINDS TO THE NORTHEAST ACROSS THE CHI AND NW IN TERMINALS...WITH RFD ALREADY SEEING NE WINDS. AS THE FRONT MOVES WINDS WILL LIKELY BECOME LIGHT AND VARIABLE WITH A SOUTH TO WEST DIRECTION. GIVEN THE RAINFALL THIS MORNING AND THE LIGHT WIND REGIME EXPECT THAT MVFR VSBY WILL PREVAIL...WITH SOME IFR TOWARDS DPA AND RFD...THROUGH AT LEAST MID MORNING AND POSSIBLY LONGER. IN ADDITION...FORECAST SOUNDINGS CONTINUE TO SHOW DEVELOPMENT OF MVFR LEVEL STRATUS DECK BY MIDDAY WHICH WOULD THEN SCATTER LATER THIS AFTERNOON. THIS SEEMS PLAUSIBLE GIVEN THE SHIFT TO A COOLER NORTHEASTERLY FLOW OFF THE LAKE AND THE ABUNDANT LOW LEVEL MOISTURE ALREADY IN PLACE. THERE IS A CHANCE THAT MIST/HAZE WILL CONTINUE THROUGH THE AFTERNOON AS WELL BUT CONFIDENCE IS LOW. NORTHEAST WINDS WILL TURN EASTERLY TONIGHT AS RIDGING BUILDS TO THE EAST AND LOW PRESSURE TAKES SHAPE ACROSS THE CENTRAL PLAINS. VFR SHOULD PREVAIL BUT SOME MVFR VSBY REDUCTION IS POSSIBLE LATE. WINDS WILL THEN TURN MORE SOUTHEASTERLY MONDAY MORNING. MDB //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM HIGH CONFIDENCE OF FOG/VIS TRENDS WITH MEDIUM CONFIDENCE OF TIMING IMPROVEMENT. * LOW MEDIUM CONFIDENCE OF A PERIOD OF 1500-2000 FT CEILINGS LATE MORNING INTO THIS AFTERNOON. * HIGH CONFIDENCE IN WIND SPEED AND DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH CHANCE TSRA. TUESDAY...VFR WITH CHANCE SHRA/TSRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. MDB && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
655 AM CDT SUN APR 1 2012 .DISCUSSION... ISSUED 300 AM CDT SUN APR 1 2012 SMALL MCS FORMED AS EXPECTED OVER EASTERN IOWA LATE IN THE EVENING...AND HAS BEEN MOVING ACROSS THE NORTHERN CWA OVERNIGHT...PRODUCING SEVERE HAIL AT TIMES. HAVE SEEN SOME SHOWERS/STORMS AS FAR SOUTH AS LINCOLN AT 2 AM. SHORT TERM...TODAY THROUGH TUESDAY... LATEST HRRR MODEL...WHICH HAS A GOOD HANDLE ON THE ACTIVITY... SHOWS MUCH OF THE RAIN SHOULD LARGELY BE OUT OF THE CWA BY SUNRISE. WILL MAKE A LAST MINUTE DECISION ON HOW LONG TO LINGER IT THIS MORNING. ONCE THAT CLEARS OUT...TEMPERATURES BECOME THE PRIMARY FOCUS. STILL LOOKING FOR HIGHS IN THE 80S ACROSS THE ENTIRE AREA...CLOSE TO THE DAILY RECORDS. HOWEVER...EVENING MODEL RUNS SHOWING A FRONTAL BOUNDARY NEAR THE I-80 CORRIDOR WILL LIKELY SLIP A BIT SOUTHWARD THIS AFTERNOON...DRIVEN BY A RATHER STIFF NORTHEAST FLOW. IF IT SLIPS TOO FAR...THEN TEMPERATURES ACROSS THE NORTHEAST CWA MAY END UP BEING COOLER THAN EXPECTED. WRF MODEL OUT OF WFO CHICAGO HAS THE BOUNDARY ALMOST ALL THE WAY TO I-74 BY 6 PM. WILL NEED TO WATCH THIS CLOSELY DURING THE AFTERNOON. BOUNDARY WILL PROBABLY REACH AT LEAST INTO PART OF THE CWA THIS EVENING...BEFORE BEGINNING TO RETREAT. SAME PROBLEM EXISTS WITH TEMPERATURES MONDAY AFTERNOON...DUE TO ITS POSITION. HAVE PULLED HIGH TEMPERATURES DOWN A BIT NORTH OF I-74...BUT STILL GOING A FEW DEGREES ABOVE GUIDANCE IN THAT AREA. REMAINDER OF THE CWA MORE LIKELY TO REACH THE 85-90 DEGREE RANGE...AGAIN NEAR THE RECORDS. TIMING OF COLD FRONTAL PASSAGE TUESDAY MORNING APPEARS TO HAVE SLOWED A BIT FROM EARLIER RUNS...SO HAVE KEPT TEMPERATURES SOUTH OF I-70 WARMER THAN PREVIOUSLY FORECAST...WITH LOWER 80S. THREAT OF SHOWERS/STORMS TO CONTINUE INTO THE AFTERNOON WITH THE BOUNDARY IN THE AREA. LONG TERM...WEDNESDAY THROUGH SATURDAY... STILL LOOKING TO BE MUCH COOLER THAN THE START OF THE WEEK...ALTHOUGH STILL A BIT ABOVE NORMAL. FOCUS IN THIS PERIOD REMAINS WITH A CUTOFF LOW WHICH WILL DEVELOP OVER THE SOUTHERN ROCKIES EARLY IN THE WEEK. LONGER RANGE MODELS IN REASONABLE AGREEMENT WITH A TRACK THAT TAKES IT SOUTH OF THE OHIO VALLEY...BUT WILL STILL SEE THE RAIN SHIELD ON THE NORTHERN FLANK EXTEND WELL TO THE NORTH. HAVE CUT BACK ON THE RAIN ACROSS THE NORTHERN CWA FOR WEDNESDAY/THURSDAY... WITH THE PERSISTENT NORTHEAST FLOW BRINGING DRIER AIR INTO CENTRAL ILLINOIS. MAINLY DRY CONDITIONS EXPECTED LATE IN THE WEEK...AS A NARROW RIDGE OF HIGH PRESSURE MOVES INTO THE MISSISSIPPI VALLEY. GEELHART && .AVIATION... ISSUED 655 AM CDT SUN APR 1 2012...FOR THE 12Z TAFS THE ONLY LINGERING MVFR CONDITIONS ARE IN DEC WITH 5SM BR AT 1145Z. STORMS HAVE MOVE EAST OF CMI...AN NO PRECIP SHOULD AFFECT ANY OF THE TERMINALS FOR MOST OF THE DAY. ACTUALLY...ALL OUR TERMINALS SHOULD BE VFR FOR MOST OF THE NEXT 24 HOURS. FORECAST SOUNDINGS CONFIRM WHAT THE CU RULE IS INDICATING FOR VFR CLOUD REDEVELOPMENT THIS AFTERNOON. THOSE CLOUDS MAY REDUCE HIGH TEMPS A LITTLE, BUT IT WILL STILL BE A VERY WARM DAY. SOME LIGHT MVFR FOG MAY FORM AGAIN LATER TONIGHT...AS A BACK DOOR COLD FRONT DROPS SOUTH INTO CENTRAL IL FROM NORTHERN IL AND N INDIANA. THE PRIMARY FOCUS FOR PRECIP WILL BE IN THE EAST...FOR CMI AND POSSIBLY DEC. WE INTRODUCED A VCSH WITH CB IN CMI AFTER 10Z. WINDS WILL SHIFT FROM SOUTHEAST EARLY IN THE TAF PERIOD TO SOUTHWEST BY MID MORNING. WIND SPEEDS MAY REACH UP NEAR 20KT AT TIMES DURING PEAK MIXING OF LATE MORNING/EARLY AFTERNOON. AS THE COLD FRONT DROPS INTO C IL TONIGHT...WINDS WILL SHIFT EAST- SOUTHEAST AGAIN...REMAINING IN THE 10-13KT RANGE FOR MOST TERMINAL SITES. LIGHT MVFR FOG MAY REDEVELOP LATE TONIGHT...ESPECIALLY FOR OUR NORTHERN TAFS OF PIA/BMI/CMI. MVFR CLOUDS WILL BE POSSIBLE AS WELL. SHIMON && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
647 AM CDT SUN APR 1 2012 .DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * SHRA/TSRA EXITING TO THE EAST 12-13Z. * FEW-SCT IFR LEVEL CLOUDS POSSIBLE NEXT HOUR OR SO...ESPECIALLY AT MDW. * MVFR MIST/HAZE EXPECTED TO CONTINUE THROUGH THE MORNING. * LIGHT/VARIABLE SOUTH/SOUTHWEST WINDS SHIFTING TO NORTHEAST BY LATE MORNING/MID-DAY. * POTENTIAL FOR PERIOD OF MVFR CEILINGS 1500-2000 FT LATE MORNING TO MID-AFTERNOON. MDB //DISCUSSION...UPDATED 12Z... EXPECT SOME RATHER VARIABLE CONDITIONS THROUGH EARLY AFTERNOON IN TERMS OF WINDS/CIGS/VSBY. CURRENTLY...SHRA/TSRA ACTIVITY ACROSS FAR NE IL IS MOVING INTO NW IN AND WILL EXIT TO THE EAST OF GYY TOWARD 14Z. NEXT CONCERNS ARE RELATED TO WEAK LOW PRESSURE WHICH WILL MOVE ALONG A FRONTAL BOUNDARY EXTENDING FROM NEAR KCID TO KRPJ TO JUST NORTH OF KPWK THIS MORNING. THIS FRONT IS EXPECTED TO SAG SOUTHWARD THROUGH THE MORNING BRINGING WINDS TO THE NORTHEAST ACROSS THE CHI AND NW IN TERMINALS...WITH RFD ALREADY SEEING NE WINDS. AS THE FRONT MOVES WINDS WILL LIKELY BECOME LIGHT AND VARIABLE WITH A SOUTH TO WEST DIRECTION. GIVEN THE RAINFALL THIS MORNING AND THE LIGHT WIND REGIME EXPECT THAT MVFR VSBY WILL PREVAIL...WITH SOME IFR TOWARDS DPA AND RFD...THROUGH AT LEAST MID MORNING AND POSSIBLY LONGER. IN ADDITION...FORECAST SOUNDINGS CONTINUE TO SHOW DEVELOPMENT OF MVFR LEVEL STRATUS DECK BY MIDDAY WHICH WOULD THEN SCATTER LATER THIS AFTERNOON. THIS SEEMS PLAUSIBLE GIVEN THE SHIFT TO A COOLER NORTHEASTERLY FLOW OFF THE LAKE AND THE ABUNDANT LOW LEVEL MOISTURE ALREADY IN PLACE. THERE IS A CHANCE THAT MIST/HAZE WILL CONTINUE THROUGH THE AFTERNOON AS WELL BUT CONFIDENCE IS LOW. NORTHEAST WINDS WILL TURN EASTERLY TONIGHT AS RIDGING BUILDS TO THE EAST AND LOW PRESSURE TAKES SHAPE ACROSS THE CENTRAL PLAINS. VFR SHOULD PREVAIL BUT SOME MVFR VSBY REDUCTION IS POSSIBLE LATE. WINDS WILL THEN TURN MORE SOUTHEASTERLY MONDAY MORNING. MDB //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN SHRA/TSRA ACTIVITY EXITING TO THE EAST 12-13Z. * MEDIUM-HIGH CONFIDENCE THAN FEW-SCT IFR LEVEL CLOUDS WILL BE SHORT LIVED THIS MORNING...CANNOT RULE OUT BRIEF BKN COVERAGE BUT PROBABILITY IS LOW. * MEDIUM CONFIDENCE IN MVFR MIST/HAZE CONTINUING FOR AT LEAST A FEW HOURS...LOW CONFIDENCE ON TIMING OF IMPROVEMENT. * HIGH CONFIDENCE IN WIND TRENDS THROUGH PERIOD AND THAT THERE WILL LIKELY BE SOME VARIABILITY IN WIND DIRECTION THROUGH MID MORNING. * MEDIUM CONFIDENCE IN PERIOD OF 1500-2000 FT CIGS LATE MORNING INTO THIS AFTERNOON. MDB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH CHANCE TSRA. TUESDAY...VFR WITH CHANCE SHRA/TSRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. MDB && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
611 AM CDT SUN APR 1 2012 ...UPDATED AVIATION DISCUSSION... .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 333 AM CDT SUN APR 1 2012 .SYNOPSIS... ISSUED AT 333 AM CDT SUN APR 1 2012 THE APRIL 1 2012 00Z 300 HPA SYNOPTIC MAP SHOWED A LARGE ANTICYCLONIC CURVED JET EXTENDING ACROSS THE WESTERN UNITED STATES AND INTO THE CANADIAN PRAIRIE PROVINCES. A JET STREAK OF AROUND 130-140 KT WAS OBSERVED FROM KREV TO KBOI. AT 500 HPA, AN AMPLIFIED TROUGH ASSOCIATED WITH THE JET STREAK WAS LOCATED ACROSS THE PACIFIC NORTHWEST AND INTO NORTHERN CALIFORNIA. CONSIDERABLE COLD AIR ADVECTION WITH 500 HPA DELTA TEMPERATURES AROUND 10 DEG C WAS OBSERVED ACROSS THE PACIFIC NORTHWEST ALONG WITH SIGNIFICANT HEIGHT FALLS. MORE LOCALLY AND AT LOWER LEVELS, A WARM AND DRY PLUME AT 700 AND 850 HPA PREVAILED ACROSS THE HIGH PLAINS. AT THE SFC, A LOW PRESSURE CENTER WAS LOCATED ACROSS EASTERN COLORADO. A DRYLINE ASSOCIATED WITH THIS FEATURE WAS LOCATED ACROSS THE SOUTHERN HIGH PLAINS AS WELL. THIS MORNING: AS WITH LAST NIGHT, HAVE FOLLOWED HRRR GUIDANCE IN CONCERNING THE POTENTIAL FOR PATCHY FOG FORMATION THIS MORNING. THIS MODEL HAS BEEN TRENDING WELL AS SITES AROUND KANSAS AND OKLAHOMA HAVE BEEN REPORTING BR THROUGH THE OVERNIGHT HOURS. I DID, HOWEVER, TAKE A MORE CONSERVATIVE APPROACH AS FAR AS DENSE FOG IS CONCERNED AND STUCK WITH PATCHY RATHER THAN +FG AS THE WINDS HAVE REMAINED ELEVATED THIS MORNING, WHICH COULD LIMIT THE OVERALL FOG INTENSITY. RECENT LAMP GUIDANCE AND RUC VIS OUTPUT SEEMS TO AGREE WITH THIS APPROACH AS WELL. FOG CONCERNS WILL BE OVER BY MID MORNING IF NOT SOONER. TODAY: UNPLEASANTLY WARM TEMPERATURES ARE EXPECTED TODAY. I SAY UNPLEASANT BECAUSE IT WILL FEEL DOWN RIGHT "HOT" RELATIVE TO THE BEGINNING OF APRIL. I DID TAKE THE COOLER SIDE OF MOS GUIDANCE AS BOISE VERIFICATION STILL SHOWS A WARM BIAS FROM THE MODELS. ONE REASON AS SUGGESTED FROM YESTERDAYS DAY SHIFT IS THAT EVAPOTRANSPIRATION FROM A RECENT HEAVY RAINFALL EVENT IS SLOWING DOWN HEAT FLUXES. IN ADDITION, DEWPOINTS ARE RUNNING AROUND 60 DEG F THIS MORNING SO THE ATMOSPHERE DOES HAVE SOME MOISTURE WHICH WILL RETARD SENSIBLE HEATING. THESE DEWPOINTS WILL LOWER AS THE DRYLINE WILL MIX EAST THROUGH THE AFTERNOON. CONVECTION IS NOT EXPECTED ALONG THE DRYLINE AS UPPER LEVEL RIDGING CONTINUES AND SUBSIDE PREVAILS AHEAD OF A WESTERN TROUGH. SOME RECORDS COULD BE IN JEOPARDY TODAY WHICH HAS BEEN HIGHLIGHTED IN THE CLIMATE SECTION BELOW. ANOTHER CONCERN FOR TODAY IS WINDS. THE 00Z GFS IS STRONGER WITH 850 HPA WINDS COMPARED TO THE 00Z NAM. THE ATMOSPHERE WILL BECOME WELL MIXED THIS AFTERNOON IN THE WAKE OF THE DRYLINE, HOWEVER WINDS PER THE MESOSCALE MODELS ARE NOT THAT IMPRESSIVE AND USING MIX DOWN TECHNIQUES SHOWS THAT A MARGINAL OR SUB MARGINAL WIND ADVISORY SPEEDS ARE POSSIBLE ACROSS THE WESTERN AND CENTRAL SECTIONS OF THE CWFA TODAY. AS A RESULT, DID NOT ISSUE A WIND ADVISORY FOR TODAY. LASTLY, CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY WHICH IS ADDRESSED BELOW IN THE FIRE WEATHER SECTION. TONIGHT: WINDS WILL GRADUALLY VEER OVERNIGHT AHEAD OF AN APPROACHING SIGNIFICANT COLD FRONT. TEMPERATURES WILL BE MILD AND GENERALLY IN THE 40S DEG F WEST TO 50S DEG F EAST. NO PRECIPITATION IS EXPECTED DURING THIS TIME FRAME AS DYNAMICS WILL NOT ARRIVE UNTIL AS DESCRIBED IN THE LONG TERM SECTION. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 243 AM CDT SUN APR 1 2012 MODELS THIS MORNING REMAIN IN GOOD AGREEMENT WITH QUICKLY MOVING AN UPPER LEVEL TROUGH WHICH WAS LOCATED JUST OFF THE WEST COAST OF CALIFORNIA TO NEAR THE FOUR CORNERS REGION BY 06Z MONDAY. THIS UPPER LEVEL SYSTEM THEN DEEPENS AS IT CROSSES NEW MEXICO DURING THE DAY ON MONDAY. BY 00Z TUESDAY THE GFS, ECMWF, AND NAM ALL PLACE THIS UPPER LEVEL LOW NEAR EAST CENTRAL NEW MEXICO. AHEAD OF THIS DEEPENING UPPER LEVEL SYSTEM A COLD FRONT WILL BE MOVING SOUTH ACROSS WESTERN KANSAS DURING THE DAY AND BASED ON THE GFS AND NAM THIS FRONTAL BOUNDARY WILL BE LOCATED NEAR THE OKLAHOMA BORDER AND SOUTH CENTRAL KANSAS BY 00Z TUESDAY. BOTH MODELS THIS MORNING ARE IN GOOD AGREEMENT WITH CONVECTION DEVELOPING ALONG THIS COLD FRONT LATE DAY DESPITE THE DIFFERENCES IN THE LOCATION OF THIS FRONT MONDAY EVENING. THE CONVECTION LATE DAY DOES APPEAR REASONABLE GIVEN THE MOISTURE RETURN FORECAST AHEAD OF THIS FRONT, IMPROVING LOW LEVEL FORCING AND LATE DAY INSTABILITY. AS A RESULT WILL CONTINUE TO FAVOR KEEPING A MENTION OF LATE DAY STORMS ACROSS SOUTH CENTRAL KANSAS AFTER 21Z. DECENT MID LEVEL INSTABILITY AT 00Z TUESDAY AND CAPES ARE FORECAST TO BE AT OR ABOVE 2000 J/KG. MARGINAL SHEAR HOWEVER IS EXPECTED WITH 0-6KM SHEAR AT OR BELOW 30KTS. STILL GIVEN SOME LATE DAY HEATING AND IMPROVING FORCING ALONG THIS BOUNDARY DO THINK A FEW STORMS THAT DO DEVELOP ALONG THIS FRONT LATE DAY MAY BECOME SEVERE WITH HAIL UP TO QUARTER SIZE BEING THE MAIN HAZARD. NORTH/NORTHWEST OF THIS COLD FRONT LATE MONDAY GUSTY NORTHERLY WINDS ARE EXPECTED TO INCREASE INTO THE 25 TO 35 MPH RANGE AS AN AREA OF LOW PRESSURE AT THE SURFACE DEEPENS ALONG THIS COLD FRONT ACROSS THE PANHANDLE OF TEXAS. THIS WILL BEGIN TO USHER IN SOME COOLER AIR LATE IN THE DAY SO TEMPERATURES BEHIND THIS COLD FRONT ARE EXPECTED TO STRUGGLE INTO THE UPPER 60S TO LOWER 70S. AHEAD OF THIS FRONT LOWER 80S STILL APPEAR LIKELY. THE CHANCES FOR PRECIPITATION THEN SPREADS NORTHWARD ACROSS ALL OF WESTERN AND MUCH OF NORTH CENTRAL KANSAS MONDAY NIGHT AS THE UPPER LEVEL LOW BEGINS TO LOWLY MOVE EAST INTO THE PANHANDLE OF TEXAS AND WARM AIR ADVECTION AND MOISTURE IMPROVES ACROSS WESTERN KANSAS DURING THE OVERNIGHT HOURS MONDAY NIGHT. FROM TUESDAY THROUGH EARLY WEDNESDAY A SERIES OF UPPER LEVEL DISTURBANCES WILL ROTATE AROUND THIS UPPER LOW AS IT MOVES FROM THE PANHANDLE OF TEXAS INTO SOUTH CENTRAL KANSAS. MOISTURE AND LIFT (WARM AIR ADVECTION, ISENTROPIC LIFT, 850-700MB FRONTOGENESIS) CONTINUES SO HAVE THEREFORE RAISE PRECIPITATION CHANCES ACROSS THE ENTIRE AREA. BY LATE WEDNESDAY AN UPPER LEVEL SHORT WAVE RIDGE WILL BEGIN TO BUILD INTO THE ROCKIES AS THE UPPER LOW CONTINUES TO TRACK EASTWARD ACROSS EASTERN KANSAS. SKIES ARE EXPECTED TO CLEAR FROM WEST TO EAST AS THE PRECIPITATION ENDS. TEMPERATURES WEDNESDAY NIGHT HAS THE POTENTIAL TO FALL BACK TO NEAR FREEZING IF SKIES CLEAR QUICK ENOUGH AND WIND GO LIGHT BUT GIVEN THE TIMING ISSUES OF THE UPPER LOW HAVE DECIDED TO STAY CLOSE TO LATEST ALLBLEND. ON THURSDAY AND FRIDAY A WARMING TREND CAN BE EXPECTED ACROSS WESTERN KANSAS AS THE UPPER LEVEL RIDGE AXIS BUILDS EAST OUT INTO THE PLAINS AND WESTERLY DOWN SLOPE FLOW IMPROVES && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 608 AM CDT SUN APR 1 2012 AREAS OF LOW IFR STATUS AND PATCHY FOG HAVE BEEN DEVELOPING ACROSS MUCH OF SOUTHWEST KANSAS EARLIER THIS MORNING. THIS WAS OCCURRING EAST OF A DRYLINE WHICH WAS LOCATED NEAR THE COLORADO BORDER. THE NAM/RUC WERE IN GOOD AGREEMENT WITH THE DRYLINE QUICKLY MOVING EAST TODAY. WHAT STATUS/FOG THAT WILL DEVELOP BETWEEN 12Z AND 14Z AT DDC AND GCK WILL QUICKLY ERODE AS A DRIER SOUTHWEST WIND DEVELOPS. THESE SOUTHWEST WINDS WILL THEN INCREASE THROUGH THE DAY INTO THE 15 TO 25 KNOT RANGE. AFTER SUNSET...WINDS WILL DECREASE BACK INTO THE 10-15 KNOT RANGE AND BACK MORE TO THE SOUTH. && .FIRE WEATHER... ISSUED AT 333 AM CDT SUN APR 1 2012 AFTER COORDINATION WITH SURROUNDING WFO`S, HAVE CONTINUED THE RFW TODAY AND ADDED CLARK COUNTY IN. THE EASTERN COLUMN OF COUNTIES IS A BIT MARGINAL AS RH`S WILL BE IN THE 15 TO 17 PERCENT RANGE. DECIDED TO ERROR ON THE SIDE OF CAUTION AND KEEP THE COUNTIES IN THE WARNING AS TODAYS HIGHS WILL BE VERY WARM AND THE MODELS TYPICALLY UNDER FORECAST DEWPOINTS IN ASSOCIATION WITH A MIXING DRYLINE AND ADIABATIC COMPRESSIONAL WARMING. && .CLIMATE... ISSUED AT 333 AM CDT SUN APR 1 2012 A VERY ANOMALOUS DAY OF EXTREMELY WARM TEMPERATURES IS EXPECTED TODAY. POSITIVE TEMPERATURE DEVIATIONS OF 20 TO 30 DEGREES IS LIKELY ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS. SOME RECORDS COULD BE BROKEN TODAY. CLIMATE RECORDS IS AS FOLLOWS: RECORD (YEAR)..........................FORECAST HIGH FOR TODAY DODGE CITY: 88 (1940, 1964)............89 MEDICINE LODGE: 93 (1946)..............86 GARDEN CITY: 87 (1964).................90 ELKHART 89 (1946)......................90 && .PRELIMINARY POINT TEMPS/POPS... DDC 89 52 71 41 / 0 10 10 60 GCK 90 50 68 40 / 0 10 10 60 EHA 90 49 63 38 / 0 10 20 50 LBL 90 50 68 40 / 0 10 20 60 HYS 88 54 70 41 / 0 10 10 50 P28 86 57 79 51 / 0 10 40 60 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 9 PM CDT /8 PM MDT/ THIS EVENING FOR KSZ030-043>045-061>064-074>078-084>088. && $$ SYNOPSIS...SUGDEN SHORT TERM...SUGDEN LONG TERM....BURGERT AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1149 AM EDT SUN APR 1 2012 .SYNOPSIS... A COLD FRONT MOVING SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY THIS AFTERNOON AND EVENING WILL PROVIDE SHOWERS WITH SCATTERED THUNDERSTORMS ACROSS OHIO AND WEST VIRGINIA. CANADIAN HIGH PRESSURE WILL PROVIDE A DRY BREAK MONDAY BEFORE THE FRONT RETURNS AS A WARM FRONT WITH SCATTERED SHOWERS AND THUNDERSTORMS TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... RECENT SATELLITE DATA SHOWS CLOUDS HAVE DECREASED FOR THE MIDDAY, BUT BLEND OF RECENT HRRR AND NAM MODEL OUTPUT SHOW CLOUDS WILL INCREASE THIS AFTERNOON AND SHOWERS WILL START TO DEVELOP NEAR A SOUTHEAST MOVING COLD FRONT ACROSS NORTHWEST PENNSYLVANIA AND A NEAR STATIONARY WARM FRONT POSITIONED JUST SOUTH OF THE I-70. RECENT HRRR AND NAM MODEL OUTPUT THEN SHOW THE COLD FRONTAL BAND OF SHOWERS, WITH SCATTERED THUNDERSTORMS OVER OHIO AND NORTHERN WEST VIRGINIA, WILL CONTINUE TO MOVE SOUTHEASTWARD ACROSS THE UPPER OHIO VALLEY INTO EVENING, EXITING THE REGION BY ABOUT MIDNIGHT. CLOUDS WILL LIKEWISE DECREASE, NORTH TO SOUTH, AS CANADIAN HIGH PRESSURE PROVIDES SUBSIDENCE AND SURFACE LAYER DRYING. ADJUSTED TEMPERATURE FORECAST TOWARD SLIGHTLY COOLER VALUES USING BLEND OF HRRR, SREF, GFS, AND NAM MODEL OUTPUT. && .SHORT TERM /MONDAY THROUGH TUESDAY/... MONDAY WEATHER LOOKS DRY WITH MODELS IN AGREEMENT IN DEPICTIONS OF DRY SURFACE HIGH SLIDING OVER THE UPPER OHIO REGION AS RIDGE ALOFT AMPLIFIES OVER THE WESTERN GREAT LAKES. COOL NORTH TO NORTHEAST WIND SHOULD LIMIT TEMPERATURE RECOVERY DESPITE SUNSHINE. READINGS WERE FORECAST USING SREF WITH AN APPROXIMATE 10 DEGREE SPREAD FM NR DUBOIS TO ZANESVILLE AS REGION WL BE UNDER BAROCLINIC ZONE TO THE EAST OF THE RIDGE AXIS. THAT BAROCLINIC ZONE/FRONTAL BOUNDARY WILL BE THE FOCUS FOR SHOWER AND THUNDERSTORM DEVELOPMENT LATE MONDAY NIGHT AND TUESDAY AS SHORTWAVE CROSSES THE LAKES AND ERODES THE RIDGE. TEMPERATURES WL MODERATE IN THE WARM ADVECTION ON THE VAN OF THAT SYSTEM. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... IN GENERAL...NORTHWEST FLOW PATTERN ACROSS THE GREAT LAKES REGION IS PROJECTED TO CONTINUE FOR THE SECOND HALF OF THE WEEK. TEMPERATURES WL THUS BE WITHIN A FEW DEGREES OF THE SEASONAL AVERAGES. HAVE PERSISTED WITH SUB CLIMO POPS...BUT CHANGES SHOULD BE ANTICIPATED AS EVENTUAL WEATHER WL BE SHORTWAVE DEPENDENT. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... LAST OF THE MVFR STRATOCUMULUS CEILINGS SHOULD EITHER DISSIPATE OR LIFT TO VFR LEVELS BY 17Z. SOUTHEASTWARD MOVING COLD FRONTAL BAND OF MVFR SHOWERS WILL MOVE FROM THE I-80 CORRIDOR AROUND 20Z TO SOUTH OF THE I-70 CORRIDOR BY 00Z. RAIN SHOWERS WILL END FROM NORTH TO SOUTH AS THE FRONT EXITS, BUT LOWER CLOUDS WILL MOVE BACK IN WITH THE CAA. EXPECT GENERAL MVFR RESTRICTIONS AT ALL PORTS, WITH THE EXCEPTION OF ZZV FOR THE LATE EVENING HOURS, THEN POSSIBLE IFR RESTRICTIONS BY LATE SUNDAY NIGHT, EARLY MONDAY MORNING. OUTLOOK...MONDAY THROUGH WEDNESDAY...MONDAY WILL BEGIN WITH IFR/MVFR CLOUDS WITH THE EXCEPTION OF ZZV THEN A RAPID IMPROVEMENT TO VFR CONDITIONS AS HIGH PRESSURE BUILDS IN. THE NEXT LOW PRESSURE SYSTEM WILL BRING RESTRICTIONS LATE TUESDAY AFT AND TUESDAY NIGHT, WITH A RETURN TO VFR LATER WEDNESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
725 AM CDT SUN APR 1 2012 .DISCUSSION...WILL CANCEL THE NORTHERN PORTION OF THE DENSE FOG ADVISORY SINCE THE LOW CLOUDS AND FOG NEVER ADVECTED THAT FAR NORTH. THE OPPORTUNITY FOR DENSE FOG ACROSS THIS AREA IS NOW MINIMAL CONSIDERING SUNRISE HAS OCCURRED. MUCH OF THE REMAINDER OF THE ADVISORY STILL HAS DENSE FOG. && .AVIATION...LIFR/IFR CIGS/VSBY WILL CONTINUE TO AFFECT KBJI INTO THE MID MORNING HOURS. THIS IS STILL A CHANCE THESE CONDITIONS WILL AFFECT FARGO. KTVF/KGFK/KDVL APPEAR THAT THEY WILL BE VFR THE REMAINDER OF THE DAY. GUSTY SOUTHEAST WINDS EXPECTED TO DEVELOP BY AFTERNOON. && .PREV DISCUSSION... /ISSUED 350 AM CDT SUN APR 1 2012/ DISCUSSION...THE DENSE FOG IS BECOMING MORE WIDESPREAD AND ADVECTING TO THE NORTH AND WEST ACCORDING TO WEB CAMS AND OBSERVATIONS. THE HRRR IS DOING AN EXCELLENT JOB WITH THIS FOG...AND WILL FOLLOW FOR THE FORECAST. ISSUED A DENSE FOG ADVISORY FOR AREAS ALONG AND SOUTH OF A VALLEY CITY TO GRAND FORKS TO BAUDETTE LINE. RADAR SHOWS SHOWERS NEAR THE INTERNATIONAL BORDER...AND THESE WILL BE NORTH OF THE DENSE FOG AREA. FAIRLY CONFIDENT THAT THE DENSE FOG WILL BE ABLE TO ADVECT INTO THE VALLEY CITY...FARGO...AND GRAND FORKS AREAS. PREV DISCUSSION... /ISSUED 310 AM CDT SUN APR 1 2012/ SHORT TERM (SUN-TUE)...INTERESTING FORECAST WITH MULTIPLE CHALLENGES. MODEL DIFFERENCES ARISE ON MONDAY WITH TIMING OF FRONT. GEM/ECMWF SLOW WHILE NAM/GFS QUICKER. ECMWF HAS BEEN CONSISTENT WITH THE SLOW SOLUTION...BUT HAD BEEN AN OUTLIER UNTIL THIS SET OF MODEL RUNS WITH THE GEM TRENDING SLOWER. WILL HAVE TO FOLLOW A BLEND. UPPER RIDGE BUILDING INTO THE REGION FOR TODAY. AHEAD OF THIS UPPER RIDGING...SCATTERED SHOWERS ASSOCIATED WITH WEAK WAVE (WARM AIR ADVECTION) POSSIBLE DURING THE EARLY MORNING HOURS...EXITING THE NE FA BY NOON. LOW-LEVEL FLOW IS INCREASING FROM THE SOUTHEAST...AND ADVECTING LOW LEVEL MOISTURE (LOW CLOUDS/FOG) BACK INTO THE REGION FROM CENTRAL MINNESOTA. FOLLOWING HRRR...EXPECT THESE CIGS TO ADVECT INTO ALL BUT THE FAR NORTHERN FA BY 12Z...THEN SCATTER WITH DAYTIME HEATING AND STRONG SE WINDS BY MID TO LATE MORNING. DENSE FOG POSSIBLE UNTIL MID-MORNING...AND WILL MONITOR CONDITIONS FOR POSSIBLE ADVISORY. SO FAR DENSE FOG IS NOT TOO WIDESPREAD...BUT HRRR SUGGESTS THAT DENSE FOG WILL BECOME WIDESPREAD BY 05Z. WINDS WILL BE CLOSE TO ADVISORY CRITERIA THIS AFTERNOON...BUT PARAMETERS SUGGEST JUST BELOW. WITH SOLAR AND GOOD MIXING...EXPECT FULL HEATING POTENTIAL...WITH MAX TEMPS AROUND 80F ACROSS THE SW FA TO UPPER 60S ACROSS THE NE FA. EXPECTED TEMP VALUES ALONG AND WEST OF THE VALLEY WILL BE RECORD HIGHS. UPPER RIDGING WILL BE BRIEF WITH UPPER FLOW BECOMING SOUTHWEST TONIGHT. STRONG 850MB JET WILL DEVELOP AND TRANSPORT MOISTURE ALONG AND AHEAD COLD FRONT. FOLLOWING MODEL COMPROMISE FOR TIMING...BEST PRECIP CHANCES WILL BE ALONG AND EAST OF THE VALLEY...FROM 06Z MON INTO THE AFTERNOON HOURS. 850MB CAPE 1000-1500 J/KG INTO THE EARLY MORNING ALONG WITH STRONG LOW-LEVEL JET ACROSS SE FA COULD LEAD TO ISOLD SEVERE HAIL (SPC HAS A 5% PROBABILITY)...ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL. UPPER TROUGH SWINGS THROUGH BY MON NIGHT. AS THIS FEATURE APPROACHES CANNOT RULE OUT SHOWERS ANYWHERE ON MONDAY...BUT HEAVIEST RAINFALL SHOULD BE IN MINNESOTA COUNTIES (AHEAD OF COLD FRONT WHERE PWATS ARE HIGHEST). CLOUDS AND COOLER AIRMASS WILL LEAD TO MUCH COLDER TEMPS ON MONDAY (ALTHOUGH STILL ABOVE NORMAL). RIDGING MOVES BACK INTO THE REGION ON TUESDAY...AND TEMPS BEGIN TO TREND WARMER AGAIN. LONG TERM (WED-SAT)...RIDGING DOMINATES INTO FRIDAY BEFORE MOVING TO THE EAST ALLOWING SW FLOW ALOFT. DRY AND WARM CONDITIONS SHOULD TRANSITION TO COOLER AND WETTER BY SATURDAY IF MODELS HAVE TIMING CORRECT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NDZ038-039- 049-052-053. MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ003-016- 017-023-024-027>032-040. && $$ TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1040 AM EDT SUN APR 1 2012 .SYNOPSIS... A FRONTAL BOUNDARY WILL DROP SOUTH INTO THE OHIO VALLEY TODAY OFFERING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS. THIS FRONT WILL PUSH INTO THE TENNESSEE VALLEY WITH SURFACE HIGH PRESSURE PROVIDING A TEMPORARY DRY PERIOD ON MONDAY. THIS FRONT IS EXPECTED TO RETURN BRINGING ADDITIONAL THUNDERSTORMS MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... DECAYING MCS WILL BRING A CHANCE FOR SHOWERS MAINLY WEST OF I-75 THROUGH THE LATE MORNING. GRADUAL CLEARING BEHIND THIS FEATURE...COMBINED WITH AMPLE WARM/MOISTURE ADVECTION FROM THE SOUTHWEST ASSOCIATED WITH A WARM FRONT WILL LEAD TO TEMPERATURES INTO THE LOW TO MID 70S ACROSS THE MAJORITY OF THE AREA BY LATE THIS AFTERNOON. NORTHWESTERLY FLOW ALOFT WILL INTENSIFY LATER TODAY AROUND THE PERIPHERY A MID/UPPER LEVEL RIDGE BUILDING ACROSS THE PLAINS. AT THE SAME TIME...A SHORTWAVE TROUGH WILL DROP ACROSS THE EASTERN GREAT LAKES. THIS SHORTWAVE WILL DEVELOP A BACK DOOR COLD FRONT WHICH WILL PUSH TOWARD THE OHIO VALLEY THIS EVENING. AHEAD OF THIS FRONT...AN INCREASINGLY UNSTABLE BOUNDARY LAYER WILL COMBINE WITH DEEP SHEAR TO DEVELOP THUNDERSTORMS ACROSS OUR AREA LATE THIS AFTERNOON AND INTO THE EVENING. SOME OF THESE STORMS HAVE THE POTENTIAL TO BECOME SEVERE. THE MAIN THREAT FROM THESE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS. HOWEVER...CANNOT RULE OUT AN ISOLATED TORNADO...PARTICULARLY IF STORMS INTERACT WITH OTHER OUTFLOW BOUNDARIES. OVERALL...CONVECTION WILL INITIATE ACROSS THE NORTH LATE THIS AFTERNOON...AND PUSH SSE ACROSS OUR SOUTH THIS EVENING WITH THE MEAN FLOW. HAVE FAVORED THE 12Z RUC FOR THIS UPDATE FOR TEMPS AND STORM TIMING. && .SHORT TERM /9 PM THIS EVENING THROUGH TUESDAY/... A BACK DOOR TYPE COLD FRONT TO DROP SOUTH THRU THE OHIO VALLEY AND STALL OUT OVER THE TN VLY OVERNIGHT. WL BUMP POPS UP TO LKLY EARLY ACRS THE SE WHERE BEST FORCING WL EXIST AND THEN TAPER PRECIP OFF FROM NORTH TO SOUTH. SOME OF THE STORMS MAY BE SEVERE DURING INTO THE EARLY EVENING HOURS WITH THE MAIN THREATS BEING WIND AND HAIL. SFC HIGH PRESSURE WILL BRIEFLY BUILD INTO THE FA MONDAY PROVIDING A TEMPORARY DRY PERIOD. HAVE TRENDED MONDAYS HIGHS A LTL COOLER ON MONDAY...FROM THE MID 60S NE TO THE MID/UPR 70S SOUTHWEST. THE MID LEVEL RIDGE WL BUILD E INTO THE REGION WITH UPPER LEVEL DISTURBANCE PASSING THRU THE GREAT LAKES TUESDAY. ASSOCIATED SFC WAVE TO TRACK THRU THE SRN GREAT LAKES. FRONT BOUNDARY TO PIVOT BACK NORTHEAST AS A WARM FRONT LATE MON NIGHT/TUE AND THEN COLD FRONT TO DROP BACK DOWN THRU THE OHIO VALLEY TUES NIGHT. NUMERICAL MODELS ARE NOT IN AGREEMENT REGARDING THIS SYSTEM AND HOW ACTIVE THE INITIAL WARM FRONT WL BE LATE MONDAY NIGHT/TUES. HAVE CHANCE/SLIGHT POPS RE-DEVELOPING LATE WITH THE BEST PROBABILITY ACRS W CENTRAL OHIO. THEN ALLOW CHC POPS TO LAY OUT E-W ON TUESDAY WITH THE APPROACH OF FRONT. CONFIDENCE IS NOT HIGH REGARDING PRECIP CHANCES TUESDAY. ETA/GFS SOLNS ARE FASTER BRINGING THE FRONT IN...WHICH THE ECMWF HOLDS IT BACK. GOING WITH A SLIGHTLY SLOWER SOLN HAVE WARM TEMPS WITH TUESDAYS FCST HIGHS RANGING FROM THE LOWER 70S FAR N TO AROUND 80 SOUTH. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HAVE FAVORED NON-GFS SOLUTION EARLY ON. THIS WOULD LEAD TO A SLOWER PROGRESSION OF A FRONT AND ASSOCIATED PRECIPITATION. HOWEVER THERE COULD BE SOME ELEVATED SHOWERS AND THUNDERSTORMS TUESDAY MORNING WELL AHEAD OF THE FRONT. BUT MOST STORMS SHOULD HOLD OFF UNTIL LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT AS THE FRONT MOVES THROUGH. THIS BOUNDARY WILL STALL IN THE TENNESSEE VALLEY AS HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES ON WEDNESDAY. A CLOSED LOW WILL PASS SOUTH OF THE REGION ON THURSDAY AND THURSDAY NIGHT WHICH MAY SPREAD SHOWERS AND THUNDERSTORMS BACK INTO THE SOUTHERN ZONES. AFTER THIS PASSES HIGH PRESSURE WILL BE ABLE TO BUILD SOUTH OVER THE REGION FOR THE END OF THE WEEK. ABOVE NORMAL TEMPERATURES AT THE BEGINNING OF THE PERIOD WILL TREND TOWARDS NORMAL BY LATER IN THE WEEK. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... WITH HIGH PRESSURE MOVING EAST...CONVECTION WILL ENTER THE REGION FROM THE WEST AS A WARM FRONTAL ZONE SETS UP THIS MORNING. THUNDERSTORMS OCCURRING OVER INDIANA WILL MOVE TO ILN TAF SITES STARTING AT 12Z. CONVECTION WITH MVFR MAY DIMINISH LATE THIS MORNING BEFORE REDEVELOPING IN THE AFTERNOON TO EARLY EVENING. WINDS WILL GUST OVER 20 KNOTS OUT OF THE SOUTHWEST DURING THE AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS ALONG THE FRONT. WINDS WILL SHIFT TO NORTHWEST IN THE EVENING AS THE WARM FRONT TRANSITIONS TO A BACK DOOR COLD FRONT...BRINGING DRIER AIR AND AN END TO THE CONVECTION. OUTLOOK...SCATTERED THUNDERSTORMS POSSIBLE MONDAY INTO TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...AR NEAR TERM...LATTO SHORT TERM...AR LONG TERM... AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS SPOKANE WA
855 AM PDT Sun Apr 1 2012 .SYNOPSIS... A low pressure system will bring rain, mountain snow and gusty winds to the Inland Northwest today. Snow levels will be around 3000 feet today which is a lower elevation than the last few days. The cooler air mass will slow the rate of mountain snow melt, which should decrease runoff into the rivers of north Idaho. Many swollen rivers will begin to recede today. The Inland Northwest will experience a break Monday and Tuesday however cool and unsettled weather will return late Tuesday and linger through the upcoming weekend. && .DISCUSSION... Another quick update to the forecast. Intense snow shower producing some brief accumulations this morning in the metro area. But it is quickly fading on radar and moving east, so this won`t last long. As this last wave moves into the Panhandle showers will continue there all day. Tougher call is what will happen behind this wave this afternoon. On the one hand the models show dry air moving in and this is confirmed by the dropping dew points at Wenatchee, Ellensburg, and Yakima. This dry air will move east into the Spokane/Pullman area this afternoon. So that will be working against afternoon showers. The flip side is climatology and the NAM model. Typically with this set up we will see afternoon showers, although they might not produce measurable precipitation. NAM wants to do this. The last run of the HRRR (10Z) doesn`t have as much coverage but it did show the typical convergence lines of showers. So have kept in the mention of showers this afternoon/evening. These could be rain or snow with no accumulation. Last item to address is the Wind Advisory. Winds are picking up in southeast Washington and this will spread northward by mid day. The problem is that the guidance is all consistent in suggesting that winds will actually subside a bit late this afternoon, during peak heating time. This typically isn`t good for strong winds so the Advisory may have a tough time verifying in some locations. Will stick with it since it will still be windy, maybe just not as strong as previously thought. RJ && .AVIATION... 12z TAFS: Rain and snow showers will be widespread through 18z over the Idaho Panhandle and far eastern Washington including the Spokane area. Ceilings of 2000 feet or lower will likely accompany the heaviest precipitation between 14z-17z. Ceilings will likely lift quickly by late morning as gusty post-frontal winds develop from Wenatchee to Spokane to Pullman. Gusts in the 30-35kt range will be possible through 22z-24z. Winds should subside early in the evening as the surface gradient between low pressure over Montana and high pressure over Oregon weakens. /GKoch && .PRELIMINARY POINT TEMPS/POPS... Spokane 44 31 52 38 61 39 / 100 20 10 10 10 60 Coeur d`Alene 43 31 50 35 61 38 / 100 30 10 10 10 70 Pullman 43 31 53 37 61 35 / 90 20 0 0 10 70 Lewiston 49 34 60 41 66 40 / 60 10 0 0 10 60 Colville 48 31 51 36 62 37 / 100 20 30 20 40 60 Sandpoint 42 30 47 34 58 38 / 100 40 20 10 10 70 Kellogg 38 31 46 33 58 36 / 100 40 20 10 10 80 Moses Lake 55 33 58 42 64 39 / 10 10 10 10 30 50 Wenatchee 51 36 56 42 58 35 / 10 10 10 10 50 40 Omak 51 31 55 39 58 35 / 20 10 20 40 60 50 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Wind Advisory until 5 PM PDT this afternoon for Idaho Palouse. WA...Wind Advisory until 5 PM PDT this afternoon for Lower Garfield and Asotin Counties-Moses Lake Area-Upper Columbia Basin- Washington Palouse-Waterville Plateau-Wenatchee Area. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
636 AM CDT SUN APR 1 2012 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT 325 AM CDT SUN APR 1 2012 MAIN FORECAST CONCERNS ARE ON STRATUS TRENDS TODAY...AS WELL AS PRECIPITATION CHANCES TONIGHT THROUGH MONDAY NIGHT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING ALONG THE WEST COAST OF THE U.S....BUILDING RIDGING DOWNSTREAM ACROSS THE PLAINS INTO MANITOBA...AND TROUGHING OVER SOUTHEAST CANADA. WITHIN THIS LATTER TROUGHING...A STRONG SHORTWAVE WAS DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO. WITH THE BUILDING RIDGING/HEIGHTS AT 500MB TAKING PLACE NEAR AND WEST OF THE FORECAST AREA...A WARM ADVECTION PATTERN IS IN PLACE. SOUNDINGS AT GRB AND MPX REFLECT THIS...SHOWING 850MB TEMPS THAT ROSE TO 9C AT 15C RESPECTIVELY AT 00Z...COMPARED TO -2C AND 9C AT 12Z YESTERDAY. THE WARM ADVECTION OCCURRING ALOFT WAS A PROBLEM GETTING RID OF THE STRATUS DURING THE DAY YESTERDAY...PLUS THE DEPTH OF THE STRATUS AT 12Z WAS 75MB...BOTH MAKING IT TOUGHER TO MIX OUT. DURING THE EVENING...INCREASING 925MB WINDS OF 30-40KT HELPED TO BRING DRIER AIR BELOW 900MB SEEN ON THE 00Z DVN SOUNDING NORTHWARD...WHICH HAS CLEARED OUT THE LOW CLOUDS UP TO A FARIBAULT MN TO OSHKOSH WI LINE. SEEING SOME FOG DEVELOP IN THE CLEARING AREA. ACROSS NORTHERN WISCONSIN...925MB WINDS HAVE TURNED NORTHWEST...IN THE WAKE OF A COLD FRONT ABOVE THE SURFACE ASSOCIATED WITH THAT NORTHERN ONTARIO SHORTWAVE. BACK FARTHER TO THE SOUTH...CONVECTION ROLLED EAST ACROSS FAR SOUTHERN WISCONSIN...EASTERN IOWA INTO NORTHERN ILLINOIS OVERNIGHT...ON THE NOSE OF A LOW LEVEL JET AND SURFACE WARM FRONT WHICH SITS NOW NEAR I-80. TODAY AND TONIGHT...UPPER RIDGING SEEN BUILDING OVER THE PLAINS WILL SHIFT EAST THROUGH TONIGHT WITH THE AXIS RIGHT OVER THE FORECAST AREA AT 12Z. WITH THE UPPER FLOW GAINING A LITTLE MORE AMPLITUDE...THAT COLD FRONT SEEN IN 925MB PROFILER/VWP DATA LOOKS TO DROP SOUTH THROUGH MUCH OF THE FORECAST AREA BETWEEN 12-18Z. THE FRONT THEN STALLS OUT FOR THE AFTERNOON FROM SOUTHWEST MINNESOTA INTO NORTHERN ILLINOIS. WITH THE 925MB WINDS VEERING NORTHEASTERLY THEN SOUTHEASTERLY BEHIND THIS FRONT...THE STRATUS WILL MAKE ITS WAY BACK SOUTH ACROSS WISCONSIN PORTIONS OF THE FORECAST AREA. QUESTION THEN BECOMES FOR THE AFTERNOON...DOES THE STRATUS MIX OUT? FOR YESTERDAY...THE 31.00Z NAM AND 31.00-07Z RUC MODELS...AS WELL AS THE HRRR...WERE ALL SAYING THE STRATUS WOULD MIX OUT BY 19Z. SEEING THE SAME THING FROM THESE MODELS TODAY. ONE ADVANTAGE TO CLEARING IS THAT DRIER AIR IS LOWER IN THE ATMOSPHERE COMPARED TO THIS TIME YESTERDAY...NOTED BETWEEN THE 12Z AND 00Z GRB SOUNDING. THIS DRIER AIR LOOKS TO CONTINUE TO SINK TOWARDS THE SURFACE TODAY WHILE MIXING OCCURS. THE COMBINATION OF THE TWO SHOULD BE ABLE TO SCOUR OUT THE STRATUS. WITH THE STRATUS CONCERNS...HAVE LOWERED TEMPERATURES CLOSER TO THE NAM12 AND REGIONAL CANADIAN 2 METER OUTPUT...WHICH SEEMS REASONABLE. CERTAINLY IF CLOUDS STICK AROUND LONGER LIKE YESTERDAY...THESE STILL MAY BE TOO HIGH. HOWEVER...DO NOT WANT TO DROP TOO MUCH GIVEN ANY SUN AND 850MB TEMPS OF 12-16C COULD EASILY JUMP TEMPERATURES WELL INTO THE 70S. TONIGHT...THE LINGERING MOISTURE COULD REDEVELOP OR EXPAND INTO A STRATUS DECK WEST OF THE MISSISSIPPI RIVER AS THE 925MB WINDS INCREASE OUT OF THE SOUTHEAST. THE INCREASING WINDS ARE IN RESPONSE TO DEEPENING LOW PRESSURE OVER NEBRASKA WITH AN INVERTED TROUGH EXTENDING NORTHEAST THROUGH WESTERN MINNESOTA. SHOULD SEE A SURGE OF ISENTROPIC LIFT WITH THIS SYSTEM AS WELL...WHICH SHOWS UP WELL ON 305K SURFACES IN THE 06-12Z MONDAY TIME PERIOD FROM LA CROSSE SOUTHWESTWARD. SOUNDINGS CONTINUE TO SUGGEST A CAPPING INVERSION AT 750MB TO PREVENT ACCAS THAT DEVELOPS FROM THE LIFT INTO BECOMING DEEP CONVECTION. WILL CONTINUE THE DRY FORECAST...BUT MONITORING OF THIS CAP IS NEEDED. FURTHER NORTH... MODELS WERE SUGGESTING BEFORE CONVECTION POSSIBLY INTO TAYLOR COUNTY. THIS IS NOW PROGGED TO STAY WELL OFF TO THE NORTHWEST...UP NEAR DULUTH. THEREFORE HAVE PULLED THE 20 PERCENT CHANCES. MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGE OVER THE FORECAST AREA IS PROGGED TO SLOWLY FALL APART...IN RESPONSE TO THE NORTHERN PORTION OF THE CURRENT WESTERN TROUGH CROSSING FROM THE NORTHERN PLAINS THROUGH THE WESTERN GREAT LAKES. THE TIMING OF THE NORTHERN FEATURE CONTINUES TO BE A PROBLEM...WITH THE ECMWF/UKMET/CANADIAN CONSISTENTLY REMAINING SLOWER THAN THE NAM/GFS. THIS HAS SIGNIFICANT IMPLICATIONS ON TEMPERATURES AND ANY PRECIP TIMING. TRENDS IN THE NAM/GFS SINCE THE 31.00Z RUNS HAVE SHOWN SOME SLOWING...THEREFORE HAVE BIASED THE FORECAST TOWARDS THE SLOWER ECMWF/UKMET/CANADIAN. ALL MODELS ARE SUGGESTING A DRIER FORECAST MONDAY...ESPECIALLY DURING THE MORNING...AS ALL SYNOPTIC FORCING IS EITHER ACROSS NORTHERN MINNESOTA OR BACK IN THE FRONTOGENETIC AREA BEHIND THE INVERTED TROUGH CROSSING MINNESOTA. HAVE REDUCED PRECIPITATION CHANCES SOME FOR MONDAY AND LATER FORECASTS MAY BE ABLE TO COMPLETELY DRY IT OUT. WITH THE TRACK OF THE UPPER TROUGH...BEST DPVA FORCING SHOULD CONTINUE TO STAY MORE TOWARDS THE NORTH FOR MONDAY NIGHT. AS SUCH...WHEN YOU LOOK AT MODEL QPF FIELDS...MOST OF THE QPF ENDS UP NORTH OF I-94. PLUS...500MB HEIGHT FALLS ARE ONLY 10-20 METERS TOPS FROM I-90 SOUTH. THEREFORE...REDUCED MONDAY NIGHTS CHANCES ABOUT 10 PERCENT SOUTH OF I-90 AND KEPT 50 CHANCES GOING NORTH OF I-94. SPC CONTINUES TO SHOW A 5% CHANCE OF SEVERE WEATHER FOR MONDAY AND MONDAY NIGHT...BUT CONFIDENCE IS REALLY LOW WITH PRECIPITATION IN THE FIRST PLACE SEEING MODEL TRENDS TOWARDS DRIER OVERALL. INVERTED TROUGH SHOULD HAVE PUSHED THROUGH THE AREA MONDAY NIGHT...ALLOWING A COOLER...DRIER AREA OF HIGH PRESSURE TO BUILD IN FOR TUESDAY AND TUESDAY NIGHT. PREVIOUS FORECAST OF DRY CONDITIONS FOR THIS TIME PERIOD STILL LOOKS GOOD...AS WELL AS THE TEMPERATURES. REGARDING TEMPERATURES MONDAY AND MONDAY NIGHT...THESE ARE TRICKY AS ALREADY MENTIONED TIMING OF THE TROUGH IS CRITICAL. THERE COULD ALSO BE SOME STRATUS AND/OR ACCAS TO DEAL WITH MONDAY. LASTLY...THE WIND FLOW MONDAY IS STILL EAST TO SOUTHEAST. ON THE OTHER HAND...850MB TEMPS ARE 12-16C. FOR NOW COOLED HIGHS ACROSS WISCONSIN WITH MORE CLOUDS AND CLOSER TO EASTERLY FLOW. LOCATIONS LIKE OELWEIN AND CHARLES CITY COULD HIT 80...THOUGH. .LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT 325 AM CDT SUN APR 1 2012 01.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES REMAIN IN GOOD AGREEMENT OF AN OMEGA BLOCK PATTERN OVER CANADA AND THE U.S. FOR WEDNESDAY THROUGH FRIDAY...THEN BEGINS TO BREAK DOWN HEADING INTO THE WEEKEND. THE FORECAST AREA LIES EAST OF THE RIDGE AXIS IN THE OMEGA BLOCK... WHICH IS IN THE DAKOTAS AND MINNESOTA THROUGH EARLY FRIDAY. THIS FAVORS A RIDGE OF HIGH PRESSURE AT THE SURFACE WITH A COOL/DRY AIR FEED OUT OF CANADA. STILL...TEMPERATURES LOOK LIKE THEY SHOULD END UP A BIT ABOVE NORMAL. MAY HAVE TO DEAL WITH FROST FOR A FEW NIGHTS...THOUGH. SOME WARMING SHOULD OCCUR ON FRIDAY AS THE UPPER RIDGE AXIS MOVES IN AND THE SURFACE RIDGE MOVES EAST... ALLOWING A SOUTHERLY RETURN FLOW TO DEVELOP. FOR THE WEEKEND...TROUGHING OVER THE WESTERN U.S. IS EXPECTED TO EJECT OUT INTO THE NORTHERN PLAINS...BRINGING A COLD FRONT INTO OR THROUGH THE FORECAST AREA SATURDAY NIGHT. ENVISION THE WEEKEND TIMING OF ALL THIS WILL GET ADJUSTED OVER THE COMING DAYS...AND HAVE SOME CONCERN THE MAJORITY OF MODELS INCLUDING THE 01.00Z ECMWF ARE TOO FAST WITH THIS TIMING GIVEN THE DOWNSTREAM RIDGE. THEREFORE...PRECIPITATION CHANCES WITH THE WARM CONVEYOR BELT AHEAD OF THE COLD FRONT ARE HELD TO 20-30 AT THIS TIME. DID NOT INTRODUCE ANY THUNDER BECAUSE THERE APPEARS TO BE LIMITED INSTABILITY AT THIS TIME. TEMPERATURES SHOULD STAY ABOVE NORMAL FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT...UNTIL THE COLD FRONT PASSES. EVEN BEHIND IT...READINGS COULD STAY NEAR OR ABOVE NORMAL. && .AVIATION...TODAY AND TONIGHT 635 AM CDT SUN APR 1 2012 LIFR/VLIFR CONDITIONS IN FOG/STRATUS CAN BE EXPECTED ACROSS SOUTHEAST MINNESOTA THROUGH MID MORNING. PLAN ON VISIBILITIES OF 1/2 MILE IN FOG AT KRST...WITH CEILINGS AT 200FT. LOOK FOR THESE CONDITIONS TO GRADUALLY START TO IMPROVE AROUND 14Z...WITH VFR CONDITIONS EXPECTED BY 16Z. MVFR VISIBILITIES AT KLSE WILL QUICKLY IMPROVE THIS MORNING WITH VFR CONDITIONS ANTICIPATED BY 14Z. STRATUS WILL PRODUCE CLOUD BASES IN THE 3 TO 4 KFT RANGE THROUGH MID MORNING BEFORE DISSIPATING. VFR CONDITIONS CAN BE EXPECTED AT THE TAF SITE THIS AFTERNOON INTO THIS EVENING. SOUTHEAST WINDS ARE EXPECTED TO INCREASE INTO THE 8 TO 16 KT RANGE THIS EVENING AS LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS. WILL HAVE TO KEEP A CLOSE WATCH ON LOW LEVEL WIND SHEAR POTENTIAL TONIGHT...WITH WINDS AROUND 1500 FT INCREASING TO 45 KTS. IN ADDITION...FORECAST SOUNDINGS ARE SHOWING THE POTENTIAL FOR AN MVFR STRATUS DECK TO DEVELOP AT KLSE AND KRST AS SOUTHEAST WINDS ADVECT 925 MB MOISTURE INTO THE AREA. WILL ALSO HAVE TO MONITOR THIS POTENTIAL VERY CLOSELY TODAY. IF THE STRATUS DEVELOPS...CLOUD BASES WILL LOWER TO AROUND 1500 FT. && .ARX WATCHES/WARNINGS/ADVISORIES... 325 AM CDT SUN APR 1 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS ALBANY NY
133 PM EDT SUN APR 1 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES AND ACROSS THE REGION THIS AFTERNOON INTO TONIGHT...ALLOWING FOR SOME RAIN SHOWERS. SOME WET SNOW MAY MIX IN WITH THE RAIN SHOWERS ACROSS THE HIGHEST TERRAIN TONIGHT. HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION PROVIDING FAIR WEATHER FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1245 PM...RADAR INDICATES SHOWERS MOVING SLIGHTLY FASTER THAN CURRENT HOURLY POPS INDICATE...SO HAVE SHIFTED HOURLY POP/WX GRIDS AHEAD BY AN HOUR. REST OF PREVIOUS FORECAST LOOKS GOOD AND WAS UNCHANGED. ****PREVIOUS DISCUSSION**** LATEST VISIBLE SATELLITE IMAGERY SHOWS THAT LOWER STRATUS CLOUDS HAVE COMPLETELY OVERTAKEN THE CWA. MEANWHILE...THE 12 UTC KALY SOUNDING SHOWS ENOUGH DRY AIR IN PLACE FOR THE BOTTOM FEW THOUSAND FEET OF THE COLUMN...AND BUFR MODEL SOUNDING SUPPORT THIS HOLDING FOR A FEW HOURS AS WELL. THE LATEST REGIONAL RADAR IMAGERY CONTINUES TO SHOW NO RETURNS ACROSS OUR AREA...BUT INCREASING AMOUNTS OF LIGHT TO MODERATE PRECIP ACROSS WESTERN NY/LAKE ONTARIO DUE TO A SHORTWAVE AND WEAK SURFACE LOW ACROSS THE GREAT LAKES. FOR NOW...WILL CONTINUE TO FORECAST CLOUDY...BUT DRY WEATHER FOR MUCH OF THE AREA THROUGH AROUND NOON. FOR THE AFTERNOON HOURS...WILL STEADILY INCREASE POPS TO CATEGORICAL FOR MOST AREAS BY THE LATE AFTN HOURS. THE NEW 12 UTC NAM AND 10 UTC 3KM HRRR ALL SHOW BATCHES OF LIGHT RAIN SHOWERS MOVING ACROSS THE AREA FROM NORTHWEST TO SOUTHEAST THROUGH THE AFTN AND EVENING HOURS...WITH THE BEST QPF ACROSS THE CATSKILLS...AS THE LOW PRESSURE WAVE MOVES ACROSS OUR AREA. ALTHOUGH QPF SHOULD BE FAIRLY LIGHT...ALL AREAS SEEM TO AT LEAST GET A FEW HUNDREDTHS...SO HIGH LIKELY/CATEGORICAL POPS SEEM WARRANTED. MAX TEMPS TODAY WILL PROBABLY BE IN THE EARLY AFTN JUST BEFORE THE START OF PRECIP...WITH TEMPS RANGING FROM THE UPPER 30S ACROSS THE SRN DACKS TO NEAR 50 IN THE MID HUDSON VALLEY. AFTER 00 UTC...WILL START TO LOWER POPS FROM NORTHWEST TO SOUTHEAST...AS MODEL GUIDANCE SHOWS THE BEST FORCING AND ASSOCIATED PRECIPITATION DROPPING SOUTHEAST OF THE REGION. AT THE HIGHEST TERRAIN /GENERALLY 2500 FT AND ABOVE/...ANY LINGERING RAIN SHOWERS COULD START TO MIX WITH OR CHANGE OVER TO SNOW SHOWERS AS TEMPS ALOFT START TO CRASH. ANY SNOW ACCUMULATION LOOKS VERY LIGHT...OF ABOUT A HALF INCH OR SO...AND MAINLY LIMITED TO THE HIGH PEAKS OF THE CATSKILLS AND HIGHEST ELEVATIONS IN SOUTHERN VERMONT. A COATING OF SNOW IS POSSIBLE ACROSS THE SOUTHERN ADIRONDACKS AS WELL. VALLEY AREAS WILL PROBABLY JUST STAY AS RAIN SHOWERS BEFORE ENDING AND NO SNOW ACCUMULATION IS EXPECTED IN ANY VALLEY AREAS AT THIS TIME. ANY PRECIP SHOULD BE FINISHED BY AROUND 06 UTC...WITH CLEARING TAKING PLACE FOR THE REMAINDER OF THE NIGHT...AS SKIES BECOME PARTLY CLOUDY. THIS SHOULD ALLOW TEMPS TO FALL OFF...WITH MIN TEMPS RANGING FROM THE 20S IN THE DACKS TO THE MID 30S IN THE CAPITAL REGION/MID HUDSON VALLEY. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... MONDAY INTO TUESDAY MODEL SUITE IS IN AGREEMENT OTHER THAN 6-9 HOURS DIFFERENCE IN TIMING OF TUES CDFNT AND INTENSITY OF 500HPA SHORT WAVES WED. FAST MOVING FLOW AT 500HPA OVER RGN...AS 500HPA TROF DEPARTS...RIDGE BUILDS EAST...ANOTHER SHORT WV FOLLOWS LATE TUESDAY. TUESDAY NIGHT SOME DIFFERENCES BEGIN TO EMERGE. AT SFC MASSIVE HIGH BUILDS FM HUDSONS BAY S INTO GRTLKS AS A SERIES OF STRONG 500HPA SHORT WVS DIVE SE ACROSS THE RGN. THE MODEL SUITE GENERALLY (GFS/GEM/12UTC ECMWF) ARE AGGRESSIVE WITH THE SHORT WAVES...THE NAM THE LEAST AND THE OUTLIER. THE MORE AGGRESSIVE SHORT WV SOLUTION RESULTS IN SOME INSTAB -SHRA/SN AT HIR TRRN...VRBL CLOUDS...BRISK N WINDS AND THIS SOLUTION IS THE ONE THE FCST WILL LEAN TWRD WITH NAM BEING THROWN OUT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... GFS AND ECMWF FAIRLY SIMILAR IN THIS PERIOD. 500HPA TROF OVER MARITIMES WILL SLOWLY DEPART...MASSIVE SFC HIGH FM HUDSONS BAY WILL BUILD INTO GRTLKS. FCA WILL BE BTWN THESE TWO SYSTEMS WITH GENERALLY DRY CONDS...SOME CLOUDS INTO FRI AS 500 HPA SHORT WAVES ROTATED ACROSS FCA. BY SAT SFC HIGH HAS MOVED INTO RGN. GFS SHIFTS 500HPA TROF OFFSHORE...ECMWF HAS CUTOFF FORM ALONG DELMARVA/SE COAST WHILE GFS KEEPS PROGRESSIVE TROFS MOVING OFFSHORE. ECMWF DEVELOPS POTENTIAL COASTAL SFC LOW THAT DRIFTS N WITH CUTOFF. THIS SYSTEM BACKS INTO FCA SUN WITH CLDS AN LT RN. FOR NOW WILL GO W/GMOS SOLUTION. SINCE ONLY DIFFERENCE IS IN DAYS 7-8. TEMPS WILL REMAIN NR NRMLS...REACHING 5 DEGREES ABV BY END OF PD. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... RAIN SHOWERS OVER CENTRAL NEW YORK AND THE MOHAWK VALLEY ARE ADVANCING EAST SOUTHEAST TOWARDS THE HUDSON VALLEY TAF SITES. WITH DRY AIR IN PLACE AT LOW LEVELS...IT MAY TAKE A LITTLE BIT UNTIL THE BOUNDARY LAYER MOISTENS UP ENOUGH TO REDUCE FLYING CONDITIONS. WITH SITES CURRENTLY VFR...IT MAY TAKE UNTIL THE MID TO LATE AFTN FOR VSBYS/CIGS TO BE REDUCED TO MVFR. RAINFALL SHOULD BE LIGHT...AND BASED ON UPSTREAM CONDITIONS...DO NOT ANTICIPATE ANY IFR CONDITIONS WITHIN THIS RAINFALL. SFC WINDS WILL BE LIGHT AND VARIABLE. RAIN SHOWERS SHOULD TAPER OFF LATER IN THE EVENING...LINGERING LONGEST /PERHAPS TOWARDS MIDNIGHT/ NEAR KPOU. AFTERWARD...WINDS WILL SWITCH TO W-NW DIRECTION AND BECOME STRONGER...ABOUT 5-10 KTS. ANY MVFR CIGS SHOULD GIVE WAY TO VFR CONDITIONS...AS LOWER CLOUDS LIFT TO 4-6 KFT AND BECOME SCT-BKN. ON MONDAY...VFR CONDITIONS ARE EXPECTED WITH JUST SCT CU AROUND 6 KFT. WITHIN DAYTIME MIXING...N-NW WINDS WILL BE GUSTY AT TIMES...ESP IN AREAS OF CHANNELED FLOW. SOME GUSTS MAY REACH 20-25 KTS...ESP BY AFTN. OUTLOOK... MON PM-TUE...VFR...NO SIG WX. TUE NT...MAINLY VFR...CHC -SHRA. WED-THU...VFR...NO SIG WX. && .FIRE WEATHER... LOW PRESSURE DROPPING SOUTHEAST FROM THE GREAT LAKES WILL MOVE ACROSS THE REGION TODAY INTO THIS EVENING...THEN A MASSIVE HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION FOR EARLY NEXT WEEK. AS SHOWERS MOVE ACROSS THE REGION...RELATIVE HUMIDITY VALUES WILL GENERALLY REMAIN ABOVE 50 PERCENT. AS THIS SYSTEM DEPARTS TONIGHT...THE WET WEATHER ALSO SUBSIDES AS RELATIVE HUMIDITIES RANGE BETWEEN 80 AND 90 PERCENT. SURFACE WINDS WILL BE WEST-SOUTHWEST AT 5 TO 15 MPH TODAY...BECOMING NORTHERLY TONIGHT AT 10 MPH OR LESS...THEN INCREASING TOWARD SUNRISE AND THROUGH THE DAY MONDAY WITH GUSTS OVER 20 MPH. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS. THE ONLY PCPN EXPECTED IN THE NEXT WEEK WILL BE A QUARTER TO THIRD INCH TODAY...ISOLATED -SHRA LATE TUESDAY. OTHERWISE WILL BE DRY WITH TEMPS BLO NORMAL AT FIRST...RISING NEAR NORMAL MID WEEK AND ENDING THE WEEK ABV NORMALS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS NEAR TERM...FRUGIS/GJM SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...FRUGIS FIRE WEATHER...BGM HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
110 AM EDT SUN APR 1 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES AND ACROSS THE REGION THIS AFTERNOON INTO TONIGHT...ALLOWING FOR SOME RAIN SHOWERS. SOME WET SNOW MAY MIX IN WITH THE RAIN SHOWERS ACROSS THE HIGHEST TERRAIN TONIGHT. HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION PROVIDING FAIR WEATHER FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1245 PM...RADAR INDICATES SHOWERS MOVING SLIGHTLY FASTER THAN CURRENT HOURLY POPS INDICATE...SO HAVE SHIFTED HOURLY POP/WX GRIDS AHEAD BY AN HOUR. REST OF PREVIOUS FORECAST LOOKS GOOD AND WAS UNCHANGED. ****PREVIOUS DISCUSSION**** LATEST VISIBLE SATELLITE IMAGERY SHOWS THAT LOWER STRATUS CLOUDS HAVE COMPLETELY OVERTAKEN THE CWA. MEANWHILE...THE 12 UTC KALY SOUNDING SHOWS ENOUGH DRY AIR IN PLACE FOR THE BOTTOM FEW THOUSAND FEET OF THE COLUMN...AND BUFR MODEL SOUNDING SUPPORT THIS HOLDING FOR A FEW HOURS AS WELL. THE LATEST REGIONAL RADAR IMAGERY CONTINUES TO SHOW NO RETURNS ACROSS OUR AREA...BUT INCREASING AMOUNTS OF LIGHT TO MODERATE PRECIP ACROSS WESTERN NY/LAKE ONTARIO DUE TO A SHORTWAVE AND WEAK SURFACE LOW ACROSS THE GREAT LAKES. FOR NOW...WILL CONTINUE TO FORECAST CLOUDY...BUT DRY WEATHER FOR MUCH OF THE AREA THROUGH AROUND NOON. FOR THE AFTERNOON HOURS...WILL STEADILY INCREASE POPS TO CATEGORICAL FOR MOST AREAS BY THE LATE AFTN HOURS. THE NEW 12 UTC NAM AND 10 UTC 3KM HRRR ALL SHOW BATCHES OF LIGHT RAIN SHOWERS MOVING ACROSS THE AREA FROM NORTHWEST TO SOUTHEAST THROUGH THE AFTN AND EVENING HOURS...WITH THE BEST QPF ACROSS THE CATSKILLS...AS THE LOW PRESSURE WAVE MOVES ACROSS OUR AREA. ALTOUGH QPF SHOULD BE FAIRLY LIGHT...ALL AREAS SEEM TO AT LEAST GET A FEW HUNDREDTHS...SO HIGH LIKELY/CATEGORICAL POPS SEEM WARRANTED. MAX TEMPS TODAY WILL PROBABLY BE IN THE EARLY AFTN JUST BEFORE THE START OF PRECIP...WITH TEMPS RANGING FROM THE UPPER 30S ACROSS THE SRN DACKS TO NEAR 50 IN THE MID HUDSON VALLEY. AFTER 00 UTC...WILL START TO LOWER POPS FROM NORTHWEST TO SOUTHEAST...AS MODEL GUIDANCES SHOWS THE BEST FORCING AND ASSOCIATED PRECIPITATION DROPPING SOUTHEAST OF THE REGION. AT THE HIGHEST TERRAIN /GENERALLY 2500 FT AND ABOVE/...ANY LINGERING RAIN SHOWERS COULD START TO MIX WITH OR CHANGE OVER TO SNOW SHOWERS AS TEMPS ALOFT START TO CRASH. ANY SNOW ACCUMULATION LOOKS VERY LIGHT...OF ABOUT A HALF INCH OR SO...AND MAINLY LIMITED TO THE HIGH PEAKS OF THE CATSKILLS AND HIGHEST ELEVATIONS IN SOUTHERN VERMONT. A COATING OF SNOW IS POSSIBLE ACROSS THE SOUTHERN ADIRONDACKS AS WELL. VALLEY AREAS WILL PROBABLY JUST STAY AS RAIN SHOWERS BEFORE ENDING AND NO SNOW ACCUMULATION IS EXPECTED IN ANY VALLEY AREAS AT THIS TIME. ANY PRECIP SHOULD BE FINISHED BY AROUND 06 UTC...WITH CLEARING TAKING PLACE FOR THE REMAINDER OF THE NIGHT...AS SKIES BECOME PARTLY CLOUDY. THIS SHOULD ALLOW TEMPS TO FALL OFF...WITH MIN TEMPS RANGING FROM THE 20S IN THE DACKS TO THE MID 30S IN THE CAPITAL REGION/MID HUDSON VALLEY. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... MONDAY INTO TUESDAY MODEL SUITE IS IN AGREEMENT OTHER THAN 6-9 HOURS DIFFERENCE IN TIMING OF TUES CDFNT AND INTENSITY OF 500HPA SHORT WAVES WED. FAST MOVING FLOW AT 500HPA OVER RGN...AS 500HPA TROF DEPARTS...RIDGE BUILDS EAST...ANOTHER SHORT WV FOLLOWS LATE TUESDAY. TUESDAY NIGHT SOME DIFFERENCES BEGIN TO EMERGE. AT SFC MASSIVE HIGH BUILDS FM HUDSONS BAY S INTO GRTLKS AS A SERIES OF STRONG 500HPA SHORT WVS DIVE SE ACROSS THE RGN. THE MODEL SUITE GENERALLY (GFS/GEM/12UTC ECMWF) ARE AGGRESSIVE WITH THE SHORT WAVES...THE NAM THE LEAST AND THE OUTLIER. THE MORE AGGRESSIVE SHORT WV SOLUTION RESULTS IN SOME INSTAB -SHRA/SN AT HIR TRRN...VRBL CLOUDS...BRISK N WINDS AND THIS SOLUTION IS THE ONE THE FCST WILL LEAN TWRD WITH NAM BEING THROWN OUT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... GFS AND ECMWF FAIRLY SIMILAR IN THIS PERIOD. 500HPA TROF OVER MARITIMES WILL SLOWLY DEPART...MASSIVE SFC HIGH FM HUDSONS BAY WILL BUILD INTO GRTLKS. FCA WILL BE BTWN THESE TWO SYSTEMS WITH GENERALLY DRY CONDS...SOME CLOUDS INTO FRI AS 500 HPA SHORT WAVES ROTATED ACROSS FCA. BY SAT SFC HIGH HAS MOVED INTO RGN. GFS SHIFTS 500HPA TROF OFFSHORE...ECMWF HAS CUTOFF FORM ALONG DELMARVA/SE COAST WHILE GFS KEEPS PROGRESSIVE TROFS MOVING OFFSHORE. ECMWF DEVELOPS POTENTIAL COASTAL SFC LOW THAT DRIFTS N WITH CUTOFF. THIS SYSTEM BACKS INTO FCA SUN WITH CLDS AN LT RN. FOR NOW WILL GO W/GMOS SOLUTION. SINCE ONLY DIFFERENCE IS IN DAYS 7-8. TEMPS WILL REMAIN NR NRMLS...REACHING 5 DEGREES ABV BY END OF PD. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS DESPITE THE EXPANDING STRATUS DECK ACROSS THE REGION. UPSTREAM SYSTEM APPROACHES DURING THE DAY WITH LOWER CIGS AND INCREASING CHANCES FOR WET CONDITIONS. THERE WILL BE A PERIOD LATER THIS AFTERNOON INTO EARLY EVENING WITH MVFR FLIGHT CONDITIONS. WINDS WILL BE LIGHT AND VARIABLE THIS EARLY SUNDAY MORNING. THOSE WINDS BECOME WEST-SOUTHWEST LATE THIS MORNING IN ADVANCE OF THIS SYSTEM AT SPEEDS LESS THAN 10KTS. WINDS QUICKLY SHIFT TO THE NORTH-NORTHWEST IN THE WAKE OF THIS STORM THIS EVENING AROUND 10 KTS AND CONTINUE OVERNIGHT. OUTLOOK... MON-TUE...VFR...NO SIG WX. TUE NT...MAINLY VFR...CHC -RA OR -SHRA. WED-THU...VFR...NO SIG WX. && .FIRE WEATHER... LOW PRESSURE DROPPING SOUTHEAST FROM THE GREAT LAKES WILL MOVE ACROSS THE REGION TODAY INTO THIS EVENING...THEN A MASSIVE HIGH PRESSURE WILL BUILD SOUTH INTO THE REGION FOR EARLY NEXT WEEK. AS SHOWERS MOVE ACROSS THE REGION...RELATIVE HUMIDITY VALUES WILL GENERALLY REMAIN ABOVE 50 PERCENT. AS THIS SYSTEM DEPARTS TONIGHT...THE WET WEATHER ALSO SUBSIDES AS RELATIVE HUMIDITIES RANGE BETWEEN 80 AND 90 PERCENT. SURFACE WINDS WILL BE WEST-SOUTHWEST AT 5 TO 15 MPH TODAY...BECOMING NORTHERLY TONIGHT AT 10 MPH OR LESS...THEN INCREASING TOWARD SUNRISE AND THROUGH THE DAY MONDAY WITH GUSTS OVER 20 MPH. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS. THE ONLY PCPN EXPECTED IN THE NEXT WEEK WILL BE A QUARTER TO THIRD INCH TODAY...ISOLATED -SHRA LATE TUESDAY. OTHERWISE WILL BE DRY WITH TEMPS BLO NORMAL AT FIRST...RISING NEAR NORMAL MID WEEK AND ENDING THE WEEK ABV NORMALS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS NEAR TERM...GJM/FRUGIS SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...BGM FIRE WEATHER...BGM HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
223 PM CDT SUN APR 1 2012 .DISCUSSION... 1005 AM CDT THE EARLY MORNING STORMS HAVE MOVED QUICKLY SOUTHEAST INTO SOUTHERN INDIANA. IN THEIR WAKE...THEY HELPED TO SINK THE FRONTAL BOUNDARY SOUTH TO NEAR INTERSTATE 88 AT AROUND 10 AM. TO THE NORTH...WHERE STRATUS AND NORTHERLY WINDS PREVAIL...TEMPERATURES HAVE BEEN BASICALLY FLAT LINE. WHILE SOME MIXING OUT OF THE STRATUS MAY OCCUR LATE THIS MORNING...REINFORCING NORTHEAST COLD AIR ADVECTION WILL EVOLVE AS A WEAK LOW SHIFTS EAST ALONG THE FRONTAL BOUNDARY. THIS SCENARIO SHOULD ENABLE THE FRONT TO MOVE SOUTH KEEPING TEMPERATURES COOLER TO THE NORTH...WITH PLACES SEEING A FALL THIS AFTERNOON ESPECIALLY IN THE NEAR DOWNSTREAM OF LAKE MICHIGAN. THE 01.12 NAM CAPTURES THIS TREND WELL...AND SEEMS TO HAVE A DECENT HANDLE ON THE STRATUS EVOLUTION...HINTING AT LOW CLOUDS ALONG AND IMMEDIATELY BEHIND THE BOUNDARY THROUGH THIS AFTERNOON. IT IS A TALE OF TWO DIFFERENT DAYS ACROSS THE CWA AS TO THE SOUTH OF THE FRONT...TEMPERATURES ARE OFF TO THE RACES WITH MID 60S ALREADY AT 10 AM IN PERU AND PONTIAC. A WARM-UP TO AROUND OR JUST ABOVE 80 DEGREES STILL LOOKS WELL IN PLACE...ESPECIALLY SEEING GUSTS TO AROUND 20 KTS ALREADY INDICATING GOOD MIXING AND CONTINUED LOW- LEVEL WARM AIR ADVECTION. THE 12Z ILX RAOB HAD NEAR 1300 J/KG OF MUCAPE WHICH SHOULD BE A GOOD BASELINE FOR WHAT IS SHIFTING OVER THE SOUTHERN FORECAST AREA AS IT CONTINUES TO WARM. THIS LOOKS TO MAXIMIZE/POOL THIS AFTERNOON BETWEEN 1500 AND 2000 J/KG IN THE FAR SOUTH...BUT IN THE ABSENCE OF ANY PRONOUNCED TRIGGER AND A QUICKLY WEAKENING LOW- LEVEL JET. THE WEAK SURFACE CIRCULATION ALONG THE BOUNDARY MAY HELP TO INCREASE CONVERGENCE SOME AS IT SHIFTS EAST THROUGH THE AFTERNOON. ALSO...AN ILL- DEFINED SHORT WAVE RIPPLE IN EASTERN IA IS SHIFTING EAST. TOGETHER IT MIGHT BE ENOUGH TO SPARK ISOLATED THUNDERSTORMS...GENERALLY SOUTH OF U.S. HIGHWAY 24 THIS AFTERNOON. ABOUT ONE THIRD OF EXPLICIT CONVECTIVE GUIDANCE LOOKED AT HAS THAT FORM OF SOLUTION. INSTABILITY PROFILES ARE ENOUGH TO WARRANT MAINLY A HAIL THREAT IF ANY STORM WERE TO SUSTAIN ITSELF. MTF //PREV DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * PERSISTENT FOG WITH 4-5SM VIS TO LINGER THROUGH THE AFTERNOON AND OVERNIGHT HOURS. * HIGH END MVFR CEILINGS THIS AFTERNOON BEFORE BECOMING VFR THIS EVENING. * NORTHEAST WINDS THIS AFTERNOON AND EVENING BECOMING EAST SOUTHEAST MONDAY MORNING. RODRIGUEZ //DISCUSSION...UPDATED 18Z... A COMPLEX WEATHER PATTERN REMAINS OVER THE TERMINALS EARLY THIS AFTERNOON AS A FRONTAL BOUNDARY IS SITUATED ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA. ITS THIS BOUNDARY WHICH IS HELPING TO PROVIDE VARYING SKY AND WEATHER CONDITIONS OVER RATHER SMALL DISTANCES. LOWER CEILINGS WHICH HAVE BEEN SITUATED OVER FAR NORTHERN ILLINOIS AND SOUTHERN WISCONSIN HAVE FINALLY WORKED THEIR WAY SOUTH OVER ALL OF THE TERMINALS...WITH THE EXCEPTION OF GYY AT THIS TIME. WITH THIS SOUTHERLY PUSH...HIGH END MVFR CEILINGS HAVE SHIFTED OVERHEAD AND EXPECT THESE CEILINGS/HEIGHTS TO REMAIN THROUGH THE REMAINDER OF THE AFTERNOON/EARLY EVENING WITH GYY ALSO OBSERVING THESE LOWER CEILINGS THIS AFTERNOON. THE OVERALL EXTENT OF THIS LOW CLOUD COVER HAS BEEN ERODING ON ALL SIDES TODAY AND EXPECT THIS TO CONTINUE AS DRIER AIR TO THE NORTH ADVECTS SOUTH...WITH CEILINGS TO SCATTER/SHIFT OUT OF THE TERMINALS LATER THIS EVENING. WITH THE BOUNDARY OVER THE TERMINALS TODAY...FOG WITH VIS OF 3-5SM HAS BEEN IN PLACE. INITIAL THOUGHTS WERE THAT THIS FOG WOULD SCATTER OUT BY MID DAY...BUT LATEST THINKING HAS SINCE CHANGED WITH LITTLE IF ANY IMPROVEMENT HAS BEEN OBSERVED. NOW THAT THESE LOWER CEILINGS HAVE MOVED OVERHEAD...DONT SEE ANY REASON WHY THE FOG WILL IMPROVE THROUGH THE REMAINDER OF THE AFTERNOON. SO HAVE INCLUDED FOG OF 4-5SM THROUGH THIS AFTERNOON AND EVENING...WITH CONDITIONS TO IMPROVE BY MONDAY MORNING. WINDS WILL HOLD OUT OF THE NORTHEAST THIS AFTERNOON WITH SOME INCREASE IN SPEED...BUT WITH NO PREVAILING GUSTS EXPECTED. THEN WINDS WILL SLOWLY SHIFT TO MORE OF AN EAST SOUTHEAST DIRECTION TONIGHT INTO MONDAY WITH SPEEDS/GUSTS INCREASING THROUGHOUT THE DAY WITH DAY TIME MIXING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM HIGH CONFIDENCE WITH FOG/VIS TRENDS. * MEDIUM CONFIDENCE WITH CEILINGS/TRENDS THIS AFTERNOON AND EVENING. * HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH CHANCE TSRA. TUESDAY...VFR WITH CHANCE SHRA/TSRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. MDB && .MARINE... 220 PM CDT LIGHT EAST TO NORTHEAST WINDS WILL BE WITH US THROUGH TUESDAY. A LARGE HIGH PRESSURE IS CURRENTLY OVER HUDSON BAY...AND A SERIES OF LOWS EXTEND FROM SASKATCHEWAN THROUGH THE CENTRAL GREAT PLAINS. AS THE LOWS MOVE EASTWARD EARLY THIS WEEK...THE GRADIENT OVER THE SOUTHERN HALF OF THE LAKE WILL TIGHTEN...BUT WINDS ARE EXPECTED TO BE 25 KT OR LESS THROUGHOUT THE FORECAST. ALTHOUGH WINDS WILL BE LIGHT...AN EXTENDED PERIOD OF EASTERLY WINDS RAISES CONCERNS OF HIGHER WAVES ACROSS THE ILLINOIS NEARSHORE ZONES. NO PLANS TO ISSUE A SMALL CRAFT ADVISORY...BUT WILL MONITOR TRENDS. THE SOUTHERN LOW WEAKENS AS IT PASSES OVER SOUTHERN LAKE MICHIGAN TUESDAY. EXACT TIMING OF WHEN THE LOW WILL PASS OVER THE LAKE IS UNCERTAIN AS THE MODELS SHOW A 6 HOUR DIFFERENCE IN TIMING. THE NORTHERN LOW MOVES EASTWARD INTO NORTHERN ONTARIO...AND ITS COLD FRONT MOVES SOUTHWARD ACROSS THE LAKE TUESDAY. WINDS WILL SHIFT FROM SOUTH TO NORTH BEHIND THE FRONT. HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT LEADING TO ANOTHER PERIOD OF NORTHEAST TO EAST WINDS OF 20 KT OR LESS THROUGH THE END OF THE WEEK. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
114 PM CDT SUN APR 1 2012 .DISCUSSION... 1005 AM CDT THE EARLY MORNING STORMS HAVE MOVED QUICKLY SOUTHEAST INTO SOUTHERN INDIANA. IN THEIR WAKE...THEY HELPED TO SINK THE FRONTAL BOUNDARY SOUTH TO NEAR INTERSTATE 88 AT AROUND 10 AM. TO THE NORTH...WHERE STRATUS AND NORTHERLY WINDS PREVAIL...TEMPERATURES HAVE BEEN BASICALLY FLAT LINE. WHILE SOME MIXING OUT OF THE STRATUS MAY OCCUR LATE THIS MORNING...REINFORCING NORTHEAST COLD AIR ADVECTION WILL EVOLVE AS A WEAK LOW SHIFTS EAST ALONG THE FRONTAL BOUNDARY. THIS SCENARIO SHOULD ENABLE THE FRONT TO MOVE SOUTH KEEPING TEMPERATURES COOLER TO THE NORTH...WITH PLACES SEEING A FALL THIS AFTERNOON ESPECIALLY IN THE NEAR DOWNSTREAM OF LAKE MICHIGAN. THE 01.12 NAM CAPTURES THIS TREND WELL...AND SEEMS TO HAVE A DECENT HANDLE ON THE STRATUS EVOLUTION...HINTING AT LOW CLOUDS ALONG AND IMMEDIATELY BEHIND THE BOUNDARY THROUGH THIS AFTERNOON. IT IS A TALE OF TWO DIFFERENT DAYS ACROSS THE CWA AS TO THE SOUTH OF THE FRONT...TEMPERATURES ARE OFF TO THE RACES WITH MID 60S ALREADY AT 10 AM IN PERU AND PONTIAC. A WARM-UP TO AROUND OR JUST ABOVE 80 DEGREES STILL LOOKS WELL IN PLACE...ESPECIALLY SEEING GUSTS TO AROUND 20 KTS ALREADY INDICATING GOOD MIXING AND CONTINUED LOW- LEVEL WARM AIR ADVECTION. THE 12Z ILX RAOB HAD NEAR 1300 J/KG OF MUCAPE WHICH SHOULD BE A GOOD BASELINE FOR WHAT IS SHIFTING OVER THE SOUTHERN FORECAST AREA AS IT CONTINUES TO WARM. THIS LOOKS TO MAXIMIZE/POOL THIS AFTERNOON BETWEEN 1500 AND 2000 J/KG IN THE FAR SOUTH...BUT IN THE ABSENCE OF ANY PRONOUNCED TRIGGER AND A QUICKLY WEAKENING LOW- LEVEL JET. THE WEAK SURFACE CIRCULATION ALONG THE BOUNDARY MAY HELP TO INCREASE CONVERGENCE SOME AS IT SHIFTS EAST THROUGH THE AFTERNOON. ALSO...AN ILL- DEFINED SHORT WAVE RIPPLE IN EASTERN IA IS SHIFTING EAST. TOGETHER IT MIGHT BE ENOUGH TO SPARK ISOLATED THUNDERSTORMS...GENERALLY SOUTH OF U.S. HIGHWAY 24 THIS AFTERNOON. ABOUT ONE THIRD OF EXPLICIT CONVECTIVE GUIDANCE LOOKED AT HAS THAT FORM OF SOLUTION. INSTABILITY PROFILES ARE ENOUGH TO WARRANT MAINLY A HAIL THREAT IF ANY STORM WERE TO SUSTAIN ITSELF. MTF //PREV DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * PERSISTENT FOG WITH 4-5SM VIS TO LINGER THROUGH THE AFTERNOON AND OVERNIGHT HOURS. * HIGH END MVFR CEILINGS THIS AFTERNOON BEFORE BECOMING VFR THIS EVENING. * NORTHEAST WINDS THIS AFTERNOON AND EVENING BECOMING EAST SOUTHEAST MONDAY MORNING. RODRIGUEZ //DISCUSSION...UPDATED 18Z... A COMPLEX WEATHER PATTERN REMAINS OVER THE TERMINALS EARLY THIS AFTERNOON AS A FRONTAL BOUNDARY IS SITUATED ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA. ITS THIS BOUNDARY WHICH IS HELPING TO PROVIDE VARYING SKY AND WEATHER CONDITIONS OVER RATHER SMALL DISTANCES. LOWER CEILINGS WHICH HAVE BEEN SITUATED OVER FAR NORTHERN ILLINOIS AND SOUTHERN WISCONSIN HAVE FINALLY WORKED THEIR WAY SOUTH OVER ALL OF THE TERMINALS...WITH THE EXCEPTION OF GYY AT THIS TIME. WITH THIS SOUTHERLY PUSH...HIGH END MVFR CEILINGS HAVE SHIFTED OVERHEAD AND EXPECT THESE CEILINGS/HEIGHTS TO REMAIN THROUGH THE REMAINDER OF THE AFTERNOON/EARLY EVENING WITH GYY ALSO OBSERVING THESE LOWER CEILINGS THIS AFTERNOON. THE OVERALL EXTENT OF THIS LOW CLOUD COVER HAS BEEN ERODING ON ALL SIDES TODAY AND EXPECT THIS TO CONTINUE AS DRIER AIR TO THE NORTH ADVECTS SOUTH...WITH CEILINGS TO SCATTER/SHIFT OUT OF THE TERMINALS LATER THIS EVENING. WITH THE BOUNDARY OVER THE TERMINALS TODAY...FOG WITH VIS OF 3-5SM HAS BEEN IN PLACE. INITIAL THOUGHTS WERE THAT THIS FOG WOULD SCATTER OUT BY MID DAY...BUT LATEST THINKING HAS SINCE CHANGED WITH LITTLE IF ANY IMPROVEMENT HAS BEEN OBSERVED. NOW THAT THESE LOWER CEILINGS HAVE MOVED OVERHEAD...DONT SEE ANY REASON WHY THE FOG WILL IMPROVE THROUGH THE REMAINDER OF THE AFTERNOON. SO HAVE INCLUDED FOG OF 4-5SM THROUGH THIS AFTERNOON AND EVENING...WITH CONDITIONS TO IMPROVE BY MONDAY MORNING. WINDS WILL HOLD OUT OF THE NORTHEAST THIS AFTERNOON WITH SOME INCREASE IN SPEED...BUT WITH NO PREVAILING GUSTS EXPECTED. THEN WINDS WILL SLOWLY SHIFT TO MORE OF AN EAST SOUTHEAST DIRECTION TONIGHT INTO MONDAY WITH SPEEDS/GUSTS INCREASING THROUGHOUT THE DAY WITH DAY TIME MIXING. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM HIGH CONFIDENCE WITH FOG/VIS TRENDS. * MEDIUM CONFIDENCE WITH CEILINGS/TRENDS THIS AFTERNOON AND EVENING. * HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH CHANCE TSRA. TUESDAY...VFR WITH CHANCE SHRA/TSRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. MDB && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1258 PM CDT SUN APR 1 2012 .DISCUSSION... ISSUED 1040 AM CDT SUN APR 1 2012 PRECIP ASSOCIATED WITH EXITING MCS WELL OFF TO THE EAST LEAVING SUNNY SKIES IN ITS WAKE. TEMPERATURES ARE QUICK TO REBOUND AS WELL...LENDING MORE CONFIDENCE TO THE WARM FORECAST. NEWEST NAM KEEPS AFTERNOON DRY...CONSIDERING THE RAPID RETREAT OF THE SHOWERS THIS MORNING...WILL KEEP ISL WORDING...AND NOT RAISE THE POP THIS AFTERNOON IN THE EAST. MINOR TWEAKS TO HRLY AND POP GRIDS. UPDATE OUT MOMENTARILY. && .AVIATION... ISSUED 1254 PM CDT SUN APR 1 2012 NEW MODELS COMING IN DRY THRU TAF PD. SWRLY/WRLY WINDS COMING AROUND TO SRLY THEN EASTERLY AFTER 06Z TONIGHT AS WEAK BOUNDARY MOVES BACK NORTH. CU THRU THE AFTERNOON SCT OUT AS LLVL STRATUS DEVELOPS WITH MOISTURE TRAPPED IN BOUNDARY LAYER ON RH TIME HEIGHTS. NOT DROPPING CIGS BELOW MVFR HOWEVER...AS PLENTY OF SUNSHINE THIS AFTERNOON MAY COUNTER AND MIX OUT A BIT MORE EFFECTIVELY THAN MOS HINTS. HJS && .PREV DISCUSSION... ISSUED 300 AM CDT SUN APR 1 2012 SMALL MCS FORMED AS EXPECTED OVER EASTERN IOWA LATE IN THE EVENING...AND HAS BEEN MOVING ACROSS THE NORTHERN CWA OVERNIGHT...PRODUCING SEVERE HAIL AT TIMES. HAVE SEEN SOME SHOWERS/STORMS AS FAR SOUTH AS LINCOLN AT 2 AM. SHORT TERM...TODAY THROUGH TUESDAY... LATEST HRRR MODEL...WHICH HAS A GOOD HANDLE ON THE ACTIVITY... SHOWS MUCH OF THE RAIN SHOULD LARGELY BE OUT OF THE CWA BY SUNRISE. WILL MAKE A LAST MINUTE DECISION ON HOW LONG TO LINGER IT THIS MORNING. ONCE THAT CLEARS OUT...TEMPERATURES BECOME THE PRIMARY FOCUS. STILL LOOKING FOR HIGHS IN THE 80S ACROSS THE ENTIRE AREA...CLOSE TO THE DAILY RECORDS. HOWEVER...EVENING MODEL RUNS SHOWING A FRONTAL BOUNDARY NEAR THE I-80 CORRIDOR WILL LIKELY SLIP A BIT SOUTHWARD THIS AFTERNOON...DRIVEN BY A RATHER STIFF NORTHEAST FLOW. IF IT SLIPS TOO FAR...THEN TEMPERATURES ACROSS THE NORTHEAST CWA MAY END UP BEING COOLER THAN EXPECTED. WRF MODEL OUT OF WFO CHICAGO HAS THE BOUNDARY ALMOST ALL THE WAY TO I-74 BY 6 PM. WILL NEED TO WATCH THIS CLOSELY DURING THE AFTERNOON. BOUNDARY WILL PROBABLY REACH AT LEAST INTO PART OF THE CWA THIS EVENING...BEFORE BEGINNING TO RETREAT. SAME PROBLEM EXISTS WITH TEMPERATURES MONDAY AFTERNOON...DUE TO ITS POSITION. HAVE PULLED HIGH TEMPERATURES DOWN A BIT NORTH OF I-74...BUT STILL GOING A FEW DEGREES ABOVE GUIDANCE IN THAT AREA. REMAINDER OF THE CWA MORE LIKELY TO REACH THE 85-90 DEGREE RANGE...AGAIN NEAR THE RECORDS. TIMING OF COLD FRONTAL PASSAGE TUESDAY MORNING APPEARS TO HAVE SLOWED A BIT FROM EARLIER RUNS...SO HAVE KEPT TEMPERATURES SOUTH OF I-70 WARMER THAN PREVIOUSLY FORECAST...WITH LOWER 80S. THREAT OF SHOWERS/STORMS TO CONTINUE INTO THE AFTERNOON WITH THE BOUNDARY IN THE AREA. LONG TERM...WEDNESDAY THROUGH SATURDAY... STILL LOOKING TO BE MUCH COOLER THAN THE START OF THE WEEK...ALTHOUGH STILL A BIT ABOVE NORMAL. FOCUS IN THIS PERIOD REMAINS WITH A CUTOFF LOW WHICH WILL DEVELOP OVER THE SOUTHERN ROCKIES EARLY IN THE WEEK. LONGER RANGE MODELS IN REASONABLE AGREEMENT WITH A TRACK THAT TAKES IT SOUTH OF THE OHIO VALLEY...BUT WILL STILL SEE THE RAIN SHIELD ON THE NORTHERN FLANK EXTEND WELL TO THE NORTH. HAVE CUT BACK ON THE RAIN ACROSS THE NORTHERN CWA FOR WEDNESDAY/THURSDAY... WITH THE PERSISTENT NORTHEAST FLOW BRINGING DRIER AIR INTO CENTRAL ILLINOIS. MAINLY DRY CONDITIONS EXPECTED LATE IN THE WEEK...AS A NARROW RIDGE OF HIGH PRESSURE MOVES INTO THE MISSISSIPPI VALLEY. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1122 AM CDT SUN APR 1 2012 .DISCUSSION... 1005 AM CDT THE EARLY MORNING STORMS HAVE MOVED QUICKLY SOUTHEAST INTO SOUTHERN INDIANA. IN THEIR WAKE...THEY HELPED TO SINK THE FRONTAL BOUNDARY SOUTH TO NEAR INTERSTATE 88 AT AROUND 10 AM. TO THE NORTH...WHERE STRATUS AND NORTHERLY WINDS PREVAIL...TEMPERATURES HAVE BEEN BASICALLY FLAT LINE. WHILE SOME MIXING OUT OF THE STRATUS MAY OCCUR LATE THIS MORNING...REINFORCING NORTHEAST COLD AIR ADVECTION WILL EVOLVE AS A WEAK LOW SHIFTS EAST ALONG THE FRONTAL BOUNDARY. THIS SCENARIO SHOULD ENABLE THE FRONT TO MOVE SOUTH KEEPING TEMPERATURES COOLER TO THE NORTH...WITH PLACES SEEING A FALL THIS AFTERNOON ESPECIALLY IN THE NEAR DOWNSTREAM OF LAKE MICHIGAN. THE 01.12 NAM CAPTURES THIS TREND WELL...AND SEEMS TO HAVE A DECENT HANDLE ON THE STRATUS EVOLUTION...HINTING AT LOW CLOUDS ALONG AND IMMEDIATELY BEHIND THE BOUNDARY THROUGH THIS AFTERNOON. IT IS A TALE OF TWO DIFFERENT DAYS ACROSS THE CWA AS TO THE SOUTH OF THE FRONT...TEMPERATURES ARE OFF TO THE RACES WITH MID 60S ALREADY AT 10 AM IN PERU AND PONTIAC. A WARM-UP TO AROUND OR JUST ABOVE 80 DEGREES STILL LOOKS WELL IN PLACE...ESPECIALLY SEEING GUSTS TO AROUND 20 KTS ALREADY INDICATING GOOD MIXING AND CONTINUED LOW- LEVEL WARM AIR ADVECTION. THE 12Z ILX RAOB HAD NEAR 1300 J/KG OF MUCAPE WHICH SHOULD BE A GOOD BASELINE FOR WHAT IS SHIFTING OVER THE SOUTHERN FORECAST AREA AS IT CONTINUES TO WARM. THIS LOOKS TO MAXIMIZE/POOL THIS AFTERNOON BETWEEN 1500 AND 2000 J/KG IN THE FAR SOUTH...BUT IN THE ABSENCE OF ANY PRONOUNCED TRIGGER AND A QUICKLY WEAKENING LOW- LEVEL JET. THE WEAK SURFACE CIRCULATION ALONG THE BOUNDARY MAY HELP TO INCREASE CONVERGENCE SOME AS IT SHIFTS EAST THROUGH THE AFTERNOON. ALSO...AN ILL- DEFINED SHORT WAVE RIPPLE IN EASTERN IA IS SHIFTING EAST. TOGETHER IT MIGHT BE ENOUGH TO SPARK ISOLATED THUNDERSTORMS...GENERALLY SOUTH OF U.S. HIGHWAY 24 THIS AFTERNOON. ABOUT ONE THIRD OF EXPLICIT CONVECTIVE GUIDANCE LOOKED AT HAS THAT FORM OF SOLUTION. INSTABILITY PROFILES ARE ENOUGH TO WARRANT MAINLY A HAIL THREAT IF ANY STORM WERE TO SUSTAIN ITSELF. MTF //PREV DISCUSSION... 315 AM CDT THIS MORNING HIGH PRESSURE OVER THE EASTERN GREAT LAKES REGION WILL PUSH EASTWARD WITH FRONTAL BOUNDARY SLOWLY TRYING TO LIFT NORTHWARD THROUGH THE EARLY MORNING HOURS. ONGOING ELEVATED CONVECTION ON NOSE OF LOW LEVEL JET WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE REGION RIDING H5 HEIGHTS DOWN THE RIDGE ALONG THE INSTABILITY GRADIENT. SEVERE THREAT THROUGH THE PREDAWN HOURS WILL REMAIN MARGINAL...BUT LATEST RUC CONTINUES TO SHOW NEAR 1000 J/KG GENERALLY ALONG AND WEST OF THE I39 CORRIDOR SUPPORTING AT LEAST SOME THREAT FOR HAIL. THREAT SHOULD TAPER THROUGH DAYBREAK THIS MORNING AS LOW LEVEL JET VEERS AND THETA E ADVECTION WEAKENS. MEANWHILE...WEAK AREA OF LOW PRESSURE NEAR LAKE SUPERIOR WILL PUSH EAST INTO SOUTHEASTERN ONTARIO BY EARLY THIS AFTERNOON. GUIDANCE SUGGESTS BAROCLINIC ZONE WILL BE FARTHER SOUTH/WEST THAN ORIGINALLY ANTICIPATED THUS BUMPED DOWN TEMPERATURES SLIGHTLY ACROSS THE AREA FOR THIS AFTERNOON. IN ADDITION WINDS TURNING TO THE NORTHEAST BY MID MORNING IN RESPONSE TO LOW MOVING ACROSS ONTARIO WILL LIMIT HIGH TEMPS ALONG THE LAKE SHORE...WITH TEMPERATURES FALLING INLAND THROUGH THE AFTERNOON AS MARINE LAYER SPREADS INLAND. MONDAY...GUIDANCE CONTINUES TO STRUGGLE WITH PLACEMENT OF BAROCLINIC ZONE/LOW PRESSURE. A LARGE TEMPERATURE SPREAD IS STILL EXPECTED TO SET UP ACROSS THE CWA. MAJORITY OF GUIDANCE SHOWS SOUTHWEST PORTIONS OF THE CWA TRYING TO REACHING THE 80 MARK...BUT WARMER TEMPERATURES ARE NOW EXPECTED TO BE FARTHER WEST. ALSO HAD TO DROP TEMPERATURES ALONG THE LAKE FRONT SEVERAL DEGREES AS LATEST GUIDANCE IN GENERAL SUGGESTS 60S POSSIBLY EVEN 50S AS WE STAY UNDER SOUTHEAST FLOW THROUGH THE DAY WITH WINDS OFF THE LAKE IN ILLINOIS. AM CONCERNED TEMPS ARE STILL A LITTLE HIGH THOUGH FOR MONDAY ALONG THE ILLINOIS SHORES. TUESDAY THOUGH SATURDAY...COLD FRONT WILL SWEEP ACROSS THE REGION TUESDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. BROAD AREA OF HIGH PRESSURE BUILDS ACROSS THE CANADIAN PRAIRIES EAST TOWARDS THE GREAT LAKE REGION THROUGH THE END OF THE WEEK. NORTHERN ILLINOIS AND NORTHWEST INDIANA WILL BE IN AREA OF NORTHERLY FLOW AND EXPECT TO BE CLIPPED BY COOLER AIR ALOFT //H85 TEMPS FALLING TO AROUND -3C THURSDAY// BEHIND THE COLD FRONT. SHOULD SEE PLENTY OF SUNSHINE FOR THE LATTER HALF OF THE WEEK. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY ABOVE NORMAL...BUT SHOULD BE MORE SEASONABLE WITH HIGHS IN THE UPPER 50S TO LOW 60S AND LOWS IN THE UPPER 30S TO LOW 40S. BMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * FOG WITH VIS OF 4-5SM THROUGH LATE MORNING...WITH CONDITIONS IMPROVING BY MID DAY. * VFR CEILINGS SCATTERING OUT BY MID AFTERNOON. * NORTHEAST WINDS STEADILY INCREASING THROUGHOUT THE DAY...WITH SOME GUSTS POSSIBLE IN THE AFTERNOON. RODRIGUEZ //DISCUSSION...UPDATED 12Z... EXPECT SOME RATHER VARIABLE CONDITIONS THROUGH EARLY AFTERNOON IN TERMS OF WINDS/CIGS/VSBY. CURRENTLY...SHRA/TSRA ACTIVITY ACROSS FAR NE IL IS MOVING INTO NW IN AND WILL EXIT TO THE EAST OF GYY TOWARD 14Z. NEXT CONCERNS ARE RELATED TO WEAK LOW PRESSURE WHICH WILL MOVE ALONG A FRONTAL BOUNDARY EXTENDING FROM NEAR KCID TO KRPJ TO JUST NORTH OF KPWK THIS MORNING. THIS FRONT IS EXPECTED TO SAG SOUTHWARD THROUGH THE MORNING BRINGING WINDS TO THE NORTHEAST ACROSS THE CHI AND NW IN TERMINALS...WITH RFD ALREADY SEEING NE WINDS. AS THE FRONT MOVES WINDS WILL LIKELY BECOME LIGHT AND VARIABLE WITH A SOUTH TO WEST DIRECTION. GIVEN THE RAINFALL THIS MORNING AND THE LIGHT WIND REGIME EXPECT THAT MVFR VSBY WILL PREVAIL...WITH SOME IFR TOWARDS DPA AND RFD...THROUGH AT LEAST MID MORNING AND POSSIBLY LONGER. IN ADDITION...FORECAST SOUNDINGS CONTINUE TO SHOW DEVELOPMENT OF MVFR LEVEL STRATUS DECK BY MIDDAY WHICH WOULD THEN SCATTER LATER THIS AFTERNOON. THIS SEEMS PLAUSIBLE GIVEN THE SHIFT TO A COOLER NORTHEASTERLY FLOW OFF THE LAKE AND THE ABUNDANT LOW LEVEL MOISTURE ALREADY IN PLACE. THERE IS A CHANCE THAT MIST/HAZE WILL CONTINUE THROUGH THE AFTERNOON AS WELL BUT CONFIDENCE IS LOW. NORTHEAST WINDS WILL TURN EASTERLY TONIGHT AS RIDGING BUILDS TO THE EAST AND LOW PRESSURE TAKES SHAPE ACROSS THE CENTRAL PLAINS. VFR SHOULD PREVAIL BUT SOME MVFR VSBY REDUCTION IS POSSIBLE LATE. WINDS WILL THEN TURN MORE SOUTHEASTERLY MONDAY MORNING. MDB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE OF FOG/VIS TRENDS AND TIMING IMPROVEMENT. * MEDIUM CONFIDENCE WITH CEILING TRENDS THROUGH THE AFTERNOON. * HIGH CONFIDENCE IN WIND SPEED AND DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH CHANCE TSRA. TUESDAY...VFR WITH CHANCE SHRA/TSRA EARLY. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. MDB && .MARINE... 210 AM CDT HIGH PRESSURE OVER OHIO EXTENDS NORTHEASTWARD ACROSS THE ST. LAWRENCE VALLEY THIS MORNING WHILE A COMPLEX SERIES OF WEAK LOW PRESSURE SYSTEMS ARE NOTED FROM LAKE SUPERIOR INTO THE MID MISSISSIPPI RIVER VALLEY...WITH BETTER ORGANIZED LOW PRESSURE IN THE LEE OF THE ROCKIES. ONE LOW...OVER LAKE SUPERIOR...WILL MOVE SOUTHEASTWARD TODAY AND MOVE OFF THE EAST COAST THIS EVENING WHERE IT WILL DEEPEN. ANOTHER AREA OF LOW PRESSURE OVER WESTERN IOWA WILL DRIFT EAST WITH A COOL FRONTAL BOUNDARY SETTING UP FROM THE FIRST LOW INTO THIS WEAKER LOW. HIGH PRESSURE WILL THEN SPREAD SOUTHWARD FROM HUDSON BAY AND INTO THE GREAT LAKES BEHIND THE LOW. AS A RESULT OF THIS FAIRLY COMPLEX PATTERN SOUTHERLY WINDS IN PLACE ACROSS LAKE MICHIGAN THIS MORNING WILL TURN NORTHEASTERLY TODAY AND EASTERLY TONIGHT...BEFORE BECOMING SOUTHEAST FOR MONDAY. IT APPEARS THAT THERE WILL BE SEVERAL PERIODS OF STRONGER WINDS FROM TONIGHT THROUGH TUESDAY AS THE PRESSURE GRADIENT MODULATES BETWEEN SYSTEMS. THE FIRST INCREASE SHOULD OCCUR TONIGHT ACROSS CENTRAL AND SOUTHERN PARTS OF THE LAKE WITH GUSTS TO AROUND 25 KT EXPECTED. SPEEDS LOOK TO EASE SOMEWHAT MONDAY BEFORE INCREASING AGAIN MONDAY EVENING THEN DROPPING OFF TUESDAY MORNING AS A LOW PASSES JUST TO THE SOUTH. THE GRADIENT TIGHTENS BEHIND THE LOW TUESDAY AFTERNOON AS STRONG HIGH PRESSURE SPREADS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS LOOKS TO BE THE PERIOD OF STRONGEST WINDS WITH 30 KT POSSIBLE FROM THE NORTH. THE HIGH THEN GRADUALLY SPREADS EASTWARD KEEPING ITS INFLUENCE OVER THE LAKE THROUGH THE END OF THE WEEK. LOWS WILL PASS TO THE EAST AND SOUTH OF THE LAKE SO PERIODS OF SLIGHTLY STRONGER WINDS WILL BE POSSIBLE DESPITE THE PRESENCE OF THE HIGH...BUT HIGHEST SPEEDS LOOK TO BE UNDER 20 KTS OR SO FROM MID WEEK ONWARD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS JACKSON KY
527 PM EDT SUN APR 1 2012 .UPDATE... ISSUED AT 526 PM EDT SUN APR 1 2012 LAST OF THE MCS IS FINALLY DEPARTING OFF TO OUR SOUTHEAST...WITH SKIES QUICKLY CLEARING ACROSS THE AREA THIS EVENING. THIS SHOULD ALLOW FOR MOST PLACES TO REACH THEIR HIGH FOR THE DAY OVER THE NEXT HOUR OR TWO AS TEMPERATURES QUICKLY SHOOT UP WITH THE SUNSHINE. WITH STABLE AREA ENTRENCHED ACROSS EASTERN KENTUCKY STRETCHING NORTH INTO SOUTHERN OHIO...ANY DEVELOPING MCS WILL BE AT LEAST 3 TO 6 HOURS BEFORE IT IMPACTS OUR NECK OF THE WOODS. WITH THIS IN MIND...HAVE GONE AHEAD AND DELAYED THE BETTER PRECIPITATION CHANCES UNTIL AFTER 04Z (MIDNIGHT). THE HRRR SEEMS TO HAVE THE BEST TIMING AND HANDLING ON THE SITUATION WITH ALL OTHER MODELS TO AGGRESSIVE ON REDEVELOPING ACTIVITY IN THE STABLE BOUNDARY LAYER OVER THE NEXT FEW HOURS. NO INDICATION THIS WILL HAPPEN AS CLOUDS ARE FEW AND FAR BETWEEN. THUS...THE HRRR INDICATION OF LATER CONVECTION SEEMS LIKE THE WAY TO GO UNTIL SOMETHING SHOWS ME OTHERWISE. STILL GOING TO BE MAINLY A HAIL THREAT...ESPECIALLY GIVEN MOST OF THE ACTIVITY SHOULD BE ELEVATED. WILL CONTINUE TO MONITOR FOR ADDITIONAL UPDATES AS EVENTS UNFOLD OVER THE NEXT 3 TO 6 HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 359 PM EDT SUN APR 1 2012 THE LEFTOVER MCS IS FINALLY MAKING AN EXIT ACROSS THE AREA...WITH THE BACK EDGE LIKELY TO EXIT BETWEEN 4 AND 5 PM. HIGHS HAVE REALLY BEEN HAMPERED BY THE CLOUD COVER...BUT DO EXPECT A LATE IN THE DAY PUSH...WITH SOME LOW TO MID 70S FOUND WEST OF I-75...WHILE MOST OTHERS RANGE FROM THE MIDDLE 60S TO AROUND 70 DEGREES. THE MODELS CONTINUE TO PLAY UP ANOTHER THUNDERSTORM COMPLEX TO DEVELOP ACROSS THE UPPER OHIO BASIN LATER THIS EVENING IN RESPONSE TO A DIGGING SHORT WAVE TROUGH WHICH WILL NOSE IN FROM THE SAINT LAWRENCE RIVER VALLEY OVERNIGHT. THE MODEL TIMING OF THIS ACTIVITY IF IT DOES HAPPEN...SEEMS A BIT FAST...AS THERE IS NOTHING POPPING YET IN NORTHERN OHIO. WILL CONTINUE TO ALLOW FOR SOME GOOD CHANCE POPS LATER TONIGHT FOR THE NORTHEAST HALF OF THE AREA...SCALING BACK QUICKLY TO SLIGHT CHANCE TO THE SOUTHWEST. AS FOR THE SEVERE THREAT...HAVE EVEN LESS CONFIDENCE IN THIS...AS WE HAVE BEEN STABILIZED BY THE STORMS THAT TOOK PLACE THIS AFTERNOON. WILL HAVE TO WAIT AND SEE HOW THE ATMOSPHERE RECOVERS TONIGHT...WITH AT LEAST LIGHT SOUTHWEST WINDS ADVECTING SOME LOW LEVEL MOISTURE...WHICH MAY RECHARGE US SOMEWHAT. THIS COMPLEX...WILL HELP DRAG A BACKDOOR COOL FRONT THROUGH THE AREA DURING THE DAY TOMORROW. BESIDES SOME LEFTOVER CONVECTION IN THE MORNING...DO NOT EXPECT ANY RE-FIRING LATER IN THE DAY...WITH THE MODEL SOUNDINGS SHOWING SOME DECENT CAPPING. THE FRONT WILL THEN MOVE BACK TO THE NORTHEAST MONDAY NIGHT AS A WARM FRONT...PERHAPS KICKING OFF SOME ISOLATED CONVECTION AS THIS OCCURS. AS FOR TEMPERATURES...ABOVE NORMAL READINGS WILL CONTINUE...ALTHOUGH READINGS HAVE COME IN A BIT COOLER FOR MONDAY WITH A LITTLE MORE COOLER AND DRIER AIR INTRUSION...SO 70S WILL MOST LIKELY BE THE RULE FOR MOST LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 PM EDT SUN APR 1 2012 A RATHER COMPLEX AND SOMEWHAT PROGRESSIVE PATTERN IS ANTICIPATED DURING THE LONG TERM PERIOD. MOST OF THE TIME THE MAIN BAND OF WESTERLIES ARE EXPECTED TO RESIDE TO OUR WEST...NORTH OR NORTHEAST WITH UPPER LEVEL RIDGING POSSIBLY DOMINATING DURING TWO DISTINCT PERIODS...WITH THE HIGHEST CHANCE OF THIS LATE IN THE PERIOD. OVERALL...MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE PATTERN WITH SOME DIFFERENCES LATER IN THE PERIOD AND SOME TIMING DIFFERENCES FROM INDIVIDUAL MODEL RUN TO MODEL RUN. EARLY ON...A WARM FRONT WILL BE MOVING NORTHEAST AND POSSIBLY EXIT NORTHEAST OF THE AREA BY TUESDAY AFTERNOON OR EVENING. MODELS GENERALLY DEVELOP PRECIP ONLY OVER THE EASTERN HALF OF THE CWA EARLY IN THE PERIOD...WITH A POSSIBLE PERIOD OF SHORTWAVE RIDGING/DRY SLOTTING OCCURRING BEFORE A COLD FRONT APPROACHES LATE IN THE DAY OR TUE NIGHT. THIS COLD FRONT WILL DROP SLOWLY SOUTH FROM TUE NIGHT INTO WED...WITH THE MODEL CONSENSUS TAKING THE BOUNDARY SOUTH OF THE CWA BY WED EVENING. HOWEVER...THE BOUNDARY SHOULD THEN STALL FOR A TIME...THOUGH THE MODELS VARY IN HOW LONG DUE TO DIFFERENCES IN HANDLING AN UPPER LOW THAT WILL MEANDER SOUTH OF A NORTHERN PLAINS/NORTHERN GREAT LAKES RIDGE FROM THE SOUTHERN ROCKIES ACROSS THE PLAINS AND MS VALLEY AND ON INTO THE EASTERN CONUS...POSSIBLY ACROSS THE TN VALLEY AND INTO THE SOUTHERN APPALACHIANS AND THEN OFF THE EASTERN SEABOARD. THIS UPPER LOW IS EXPECTED TO FOLLOW THIS MEANDERING PATH FROM THE START OF THE PERIOD ON TUE THROUGH FRI. AS MENTIONED BY THE PREVIOUS FORECASTER....BUT FRI IT SHOULD FINALLY GET PICKED UP BY A TROUGH TO ITS NORTHEAST AND THIS SHOULD THEN TAKE IT OUT TO SEA. THEREAFTER...THE MODEL CONSENSUS IS FOR THE UPPER LEVEL RIDGE TO BUILD IN AND DOMINATE THAT LAST TWO TO TWO AND A HALF DAYS OF THE PERIOD. AS FOR POPS...WENT WITH SLIGHT CHANCE TO CHANCE POPS EARLY ON TUE WITH THE WARM FRONT AND THEN INCREASED POPS LATE ON TUE INTO TUE EVENING IN ADVANCE OF THE APPROACHING COLD FRONT AND SHORTWAVE THAT THE MODEL CONSENSUS TAKES ACROSS THE OH VALLEY REGION OR THE CWA ON TUE NIGHT. THE BOUNDARY SHOULD CONTINUE SLIPPING SOUTH ON WED AND CONTINUED CHANCE POPS DURING WED...BUT GRADUALLY LOWERED POPS IN THE NORTH FARTHER AWAY FROM THE BOUNDARY. A SFC LOW MAY DEVELOP ALONG THE BOUNDARY AS THE UPPER LOW APPROACHES AROUND MIDWEEK AND SLOW THE SOUTHWARD PROGRESS OF THE FRONT AND HOLD IN CHANCES FOR ISOLATED TO SCATTERED CONVECTION AS THE SFC LOW AND UPPER SYSTEM PROBABLY TRACK JUST TO OUR SOUTH ACROSS THE TN VALLEYS. ONCE THE UPPER SYSTEM TRACKS EAST...PRECIP CHANCES WILL DIMINISH LATE THU NIGHT OR FRI. FOR NOW THE END OF THE FORECAST IS EXPECTED TO BE DRY...WITH UPPER LEVEL RIDGING DOMINATING. WITH THIS RIDGE...OPTED TO FAVOR THE ECMWF RUNS. TEMPERATURES SHOULD BE WARMEST AND MOST ABOVE NORMAL ON TUESDAY AND THEN MORE MODEST DEPARTURES OF ABOUT 5 DEGREES ABOVE NORMAL AT THE END OF THE PERIOD. OVERNIGHT LOWS SHOULD AVERAGE AT LEAST 5 DEGREES ABOVE NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 158 PM EDT SUN APR 1 2012 A COMPLEX OF SHOWERS AND THUNDERSTORMS WILL GRADUALLY WEAKEN AND EXIT OFF TO THE SOUTHEAST IN THE NEXT FEW HOURS...ALLOWING FOR AT LEAST TEMPORARILY IMPROVING CONDITIONS AT SME AND LOZ. VFR CONDITIONS WILL RETURN...ALTHOUGH THERE WILL BE A RENEWED THREAT OF CONVECTION THIS EVENING AND INTO THE OVERNIGHT HOURS TONIGHT...HOWEVER WILL ONLY MAINTAIN THE VCTS WORDING FOR NOW...AS CONFIDENCE REMAINS LOW IN WHERE AND WHEN THE CONVECTION WILL OCCUR. RIGHT NOW...IT DOES APPEAR THAT THE BETTER THREAT WILL BE ALONG AND EAST OF A LINE FROM MOREHEAD...TO JACKSON...TO HARLAN. .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...GEOGERIAN LONG TERM....JP AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
412 PM EDT SUN APR 1 2012 .SYNOPSIS... A COLD FRONT MOVING SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY TONIGHT WILL SPAWN SHOWERS AND SCATTERED EVENING THUNDERSTORMS. CANADIAN HIGH PRESSURE WILL THEN PROVIDE DRY SEASONABLE WEATHER MONDAY. A LOW PRESSURE SYSTEM, COMING SOUTHEAST FROM MONTANA, WILL BRING SHOWERS AND SCATTERED THUNDERSTORMS TUESDAY AFTERNOON AND NIGHT. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT SHOW A SLOWER DEVELOPMENT OF THE COLD FRONTAL SHOWER BAND ACROSS THE I-80 CORRIDOR. THIS MAY BE DUE TO SURFACE LAYER DRYNESS WHICH WOULD INHIBIT INSTABILITY. THIS WOULD LIKEWISE INHIBIT THUNDERSTORM DEVELOPMENT THIS EVENING, BUT AT THIS JUNCTURE HAVE NOT OMITTED MENTION OF SCATTERED EVENING THUNDERSTORMS. CONCUR WITH RECENT HRRR THAT ANY REMAINING SHOWERS WILL HAVE EXITED SOUTH INTO CENTRAL WEST VIRGINIA BY LATE TONIGHT. FORECASTED TEMPERATURES TONIGHT USING BLEND OF HRRR, LAMP, AND NAM MODEL OUTPUT WHICH YIELDED VALUES EITHER NEAR OR SLIGHTLY WARMER THAN NORMAL. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... BLEND OF RECENT SREF MODEL OUTPUT SHOWS CANADIAN HIGH PRESSURE PROVIDING SUBSIDENCE AND DRYING MONDAY. HENCE EXPECT SUNSHINE TO BE PREVALENT. LOW PRESSURE SYSTEM, COMING SOUTHEAST FROM MONTANA, WILL NEXT SPREAD CLOUDS EASTWARD ACROSS THE UPPER OHIO VALLEY STARTING LATE MONDAY NIGHT. HAVE MAINTAINED A FORECAST OF A CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY AFTERNOON AND NIGHT WITH THE EASTWARD PASSAGE OF THE LOW PRESSURE CENTER ACROSS THE UPPER OHIO VALLEY. HIGH PRESSURE WILL FOLLOW WITH DRY CONDITIONS WEDNESDAY. FORECASTED TEMPERATURES, USING CONSENSUS OF SREF, GFS AND NAM GUIDANCE, TO BE NEAR NORMAL MONDAY, 7 TO 10 DEGREES WARMER THAN NORMAL TUESDAY, AND NO MORE LIKE 3 TO 5 DEGREES WARMER THAN NORMAL DAYTIME WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... DRY WEATHER SHOULD PREVAIL ACROSS THE UPPER OHIO VALLEY REGION INTO THE WEEKEND AS A LARGE AREA OF HIGH PRESSURE SLIDES SOUTHEAST ACROSS THE GREAT LAKES. A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK EASTWARD FROM THE LOWER MS VALLEY TO OFF SOUTHEAST COAST LATE IN THE WEEK. THE BULK OF ASSOCIATED MOISTURE IS PROGGED TO REMAIN SOUTH OF THE FORECAST AREA. HPC GUIDANCE SHOWS THE NEXT COLD FRONT APPROACHING FROM THE WEST WITH A CHANCE OF SHOWERS LATE SUNDAY. TEMPERATURES ARE FORECAST TO BE NEAR NORMAL THROUGH FRIDAY...THEN WARMING TO AROUND 10 DEGREES ABOVE NORMAL DURING THE WEEKEND. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... A SHORTWAVE TROUGH WILL CONTINUE TO PLUNGE SOUTHEAST OFF THE MID ATLANTIC COAST EARLY TONIGHT. THE ASSOCIATED WEAK SURFACE REFLECTION AND COLD FRONT WILL MOVE ACROSS THE TERMINALS EARLY TONIGHT. SCATTERED SHOWERS WITH BRIEF MVFR RESTRICTIONS ARE EXPECTED AS THE SYSTEM MOVES THROUGH...FOLLOWED BY GENERALLY MVFR CEILINGS BEHIND THE FRONT OVERNIGHT. CONDITIONS ARE FORECAST TO IMPROVE TO VFR BY LATE MONDAY MORNING AS A SURFACE RIDGE BUILDS IN FROM THE NORTH. SOUTHWEST SURFACE WINDS WILL BECOME NORTHWEST AROUND 10KT BEHIND THE FRONTAL BOUNDARY TONIGHT. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... ANOTHER SHORTWAVE TROUGH AND COLD FRONT WILL BRING SCATTERED SHOWERS AND THE POTENTIAL FOR RESTRICTIONS LATE TUESDAY INTO TUESDAY NIGHT. A RETURN TO PREDOMINATELY VFR WEATHER IS EXPECTED WEDNESDAY THROUGH FRIDAY AS HIGH PRESSURE SLIDES ACROSS THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
307 PM EDT SUN APR 1 2012 .SYNOPSIS... A COLD FRONT WILL PASS THROUGH THE REGION TONIGHT BEFORE HIGH PRESSURE BUILDS OVERHEAD MONDAY THROUGH MONDAY NIGHT. HIGH PRESSURE WILL MOVE OFF THE COAST TUESDAY AND ANOTHER COLD FRONT WILL IMPACT THE REGION WEDNESDAY. HIGH PRESSURE IS EXPECTED TO BUILD OVERHEAD LATE IN THE WEEK. && .NEAR TERM /THROUGH MONDAY/... CU/STRATOCU FIELD EAST OF THE BLUE RIDGE WAS BREAKING UP/SCATTERING THIS AFTERNOON. THIS WILL ALLOW FOR PARTIAL SUNSHINE THIS AFTERNOON BEFORE THE NEXT BATCH OF CLOUDS ROLLS IN BY EARLY EVENING. HAVE A FEW SHOWERS MAKING THEIR WAY INTO CENTRAL PENNSYLVANIA AT 2 PM. SOUTHERN EDGE MAY CLIP MARYLAND COUNTIES ALONG THE MASON DIXON LINE THIS AFTERNOON BUT PER HRRR GUIDANCE THE BULK OF THESE STAY TO THE NORTH/NORTHEAST OF THE CWA THIS AFTERNOON. HOWEVER...AS LOW PRESSURE AND A COLD FRONT APPROACH FROM THE WEST...EXPECT A NEW AREA OF SHOWERS TO DEVELOP AND PRESS SOUTH THROUGH THE EVENING/OVERNIGHT HOURS. WRF-ARW SEEMS A LITTLE ON THE FAST SIDE...AND PREFER THE TIMING/EVOLUTION INDICATED BY THE HRRR WHICH HAS GENERAL SUPPORT FROM THE NAM/GFS/SREFS. HAVE INCREASED POPS TO CATEGORICAL ACROSS THE NORTHERN HALF OF THE CWA...WITH HIGH CHANCE TO LIKELY ACROSS THE SOUTHERN REACHES OF THE CWA. GIVEN TIME OF DAY/RELATIVE LACK OF INSTABILITY...HAVE LOW CONFIDENCE IN THUNDERSTORMS. HAVE ALLOWED FOR ISOLATED EVENING THUNDER ACROSS THE WEST WHERE SUNSHINE THIS AFTERNOON HAS BEEN LONGER AND WHERE THERE MAY BE A LITTLE INSTABILITY. FURTHER EAST...ONLY P-TYPE INCLUDED IS SHOWERS. LOW PRESSURE SHOULD BE OFF THE COAST AND THE COLD FRONT SOUTH OF THE AREA BY AROUND 10Z MONDAY. SKIES WILL CLEAR OUT BEHIND THE FRONT...PAVING THE WAY FOR PLENTY OF SUNSHINE. HOWEVER WITH SUNSHINE MIXING WILL BE DECENT AND EXPECT WIND GUSTS AOA 25 MPH. LEANED TOWARD THE WARMER SET OF MOS FOR MAX T ON MONDAY...WHICH RANGES FROM LOWER 60S ACROSS NORTHEAST MARYLAND TO UPPER 60S TOWARD THE CENTRAL VA FOOTHILLS. && .SHORT TERM /MONDAY NIGHT/... SURFACE HIGH PRESSURE WILL BUILD OVERHEAD MONDAY NIGHT...CAUSING DRY AND SEASONABLY CHILLY CONDITIONS. LIGHT WINDS...DRY AIR AND MAINLY CLEAR SKIES WILL PROVIDE A GOOD SETUP FOR RADIATIONAL COOLING. MIN TEMPS WILL RANGE FROM THE LOWER AND MIDDLE 30S ACROSS NORTHERN MARYLAND INTO EASTERN WEST VIRGINIA AND NORTHERN VIRGINIA...TO THE LOWER AND MIDDLE 40S IN DOWNTOWN WASHINGTON/BALTIMORE AND LOWER SOUTHERN MARYLAND. AREAS OF FROST ARE POSSIBLE ACROSS PORTIONS OF THE NORTHERN MARYLAND...EASTERN WEST VIRGINIA AND NORTHERN VIRGINIA LATE MONDAY NIGHT. A FROST ADVISORY MAY BE NEEDED. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGH PRESSURE WILL MOVE OFF THE COAST TUESDAY AND A RETURN FLOW FROM THE SOUTH WILL USHER IN MILD CONDITIONS. MAX TEMPS WILL RANGE FROM THE MID 60S ACROSS NORTHEASTERN MARYLAND TO THE MIDDLE 70S ACROSS CENTRAL VIRGINIA. WARM AND MOIST AIR WILL LEAD TO LIMITED INSTABILITY ACROSS THE POTOMAC HIGHLANDS AND SHENANDOAH VALLEY. SCATTERED SHOWERS/T-STORMS ARE POSSIBLE ACROSS THESE AREAS LATE IN THE DAY. A COLD FRONT WILL PASS THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. A FEW SHOWERS ARE POSSIBLE ALONG AND AHEAD OF THE COLD FRONT. THE BEST CHANCE FOR PRECIPITATION WILL BE ACROSS CENTRAL VIRGINIA AND LOWER SOUTHERN MARYLAND WEDNESDAY AFTERNOON. HIGH PRESSURE WILL BUILD IN BEHIND THIS SYSTEM WEDNESDAY NIGHT THROUGH THURSDAY...BRINGING DRY AND SEASONABLE CONDITIONS. A STORM SYSTEM WILL PASS BY TO OUR SOUTH THURSDAY NIGHT AND FRIDAY. AS OF NOW IT APPEARS THAT IT WILL BE TOO FAR TO OUR SOUTH TO HAVE A SIGNIFICANT IMPACT ON OUR WEATHER...BUT THE CERTAINTY REMAINS LOW THIS FAR OUT. HIGH PRESSURE WILL RETURN NEXT WEEKEND BEHIND THIS SYSTEM. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... MAINLY VFR CU/STRATOCU WILL CONTINUE TO BREAK UP THIS AFTERNOON BEFORE CLOUDS ROLL BACK IN THIS EVENING. LOW PRESSURE/FRONT WILL BRING THE LIKELIHOOD OF SHOWERS TONIGHT DURING A SEVERAL HOUR WINDOW. TIMING FROM HRRR MODEL LOOKS REASONABLE. INCLUDED MVFR RESTRICTIONS IN SHOWERS. WINDS SHIFT TO THE NORTHWEST OVERNIGHT AND BECOME GUSTY. GUSTS AOA 25 KT ARE EXPECTED ON MONDAY BEFORE DIMINISHING LATE. HIGH PRESSURE WILL BUILD OVER THE TERMINALS MONDAY NIGHT BEFORE MOVING OFF THE COAST TUESDAY. VFR CONDITIONS ARE EXPECTED DURING THIS TIME. A COLD FRONT WILL BRING THE CHANCE FOR SHOWERS TUESDAY NIGHT AND WEDNESDAY. THE TIMING OF THE FRONTAL PASSAGE REMAINS UNCERTAIN THIS FAR OUT...BUT IF THE FRONTAL PASSAGE IS SLOW ENOUGH THEN THUNDERSTORMS ARE POSSIBLE WEDNESDAY AFTERNOON. HIGH PRESSURE WILL RETURN FOR LATE IN THE WEEK. && .MARINE... WILL HAVE TO WATCH SOUTHERLY FLOW THIS EVENING. WINDS HAVE REMAINED IN CHECK /AROUND 10 KT/ SO FAR THIS AFTERNOON...BUT CHANNELLING THIS EVENING COULD BRING WINDS CLOSE TO SCA THRESHOLDS UP THE BAY. HIGHER CONFIDENCE EXISTS IN SCA CONDITIONS WITH A FROPA/WIND SHIFT TO THE NORTHWEST TONIGHT AND CONTINUING INTO MONDAY. HIGH PRESSURE WILL BUILD OVER THE WATERS MONDAY NIGHT BEFORE MOVING OFF THE COAST TUESDAY. NORTHWEST WINDS AHEAD OF THE HIGH WILL GUST PAST SCA CRITERIA CROSS THE MIDDLE PORTION OF THE BAY AND LOWER TIDAL POTOMAC RIVER. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THESE AREAS. WINDS WILL DIMINISH TOWARD TUESDAY MORNING AS HIGH PRESSURE BUILDS OVERHEAD. A RETURN FLOW WILL DEVELOP AROUND THE DEPARTING HIGH TUESDAY. A COLD FRONT WILL PASS THROUGH THE WATERS LATE TUESDAY NIGHT INTO WEDNESDAY. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS DURING THIS TIME. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT LATE IN THE WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS THURSDAY. && .TIDES/COASTAL FLOODING... WILL CONTINUE COASTAL FLOOD ADVISORY THROUGH HIGH TIDE TIMES IN COUNTIES ADJACENT TO THE UPPER BAY THIS AFTERNOON. AT 2 PM...ANNAPOLIS REMAINED ABOUT 2.5 FT MLWW BUT WILL BE ON THE WAY DOWN OVER THE NEXT COUPLE OF HOURS. BIG QUESTION IS WHAT OCCURS ON THE OVERNIGHT HIGH TIDE CYCLE. THERE IS THE CHANCE THAT ANOMALIES MAY REMAIN STEADY AND IF THAT IS THE CASE THE COASTAL FLOOD ADVISORY MAY NEED TO BE EXTENDED FOR THE NEXT HIGH TIDE CYCLE BEFORE NORTHWEST WINDS DRIVE WATER OUT OF THE BAY OVERNIGHT INTO MONDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...COASTAL FLOOD ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MDZ007- 011-014-018. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 8 PM EDT MONDAY FOR ANZ530- 531-535-536-538-539. SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 2 AM EDT TUESDAY FOR ANZ532>534-537-540>543. && $$ SYNOPSIS...BPP/BJL NEAR TERM...BPP SHORT TERM...BJL LONG TERM...BJL AVIATION...BPP/BJL MARINE...BPP/BJL TIDES/COASTAL FLOODING...BPP
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
347 PM EDT SUN APR 1 2012 .SYNOPSIS... ISSUED AT 347 PM EDT SUN APR 1 2012 A STALLED FRONT WILL BRING SOME ISOLATED SHOWERS THIS EVENING. FAIR WEATHER IS EXPECTED FOR MONDAY THEN SOME SHOWERS AND AN ISOLATED THUNDERSTORM IS POSSIBLE MONDAY NIGHT AS LOW PRESSURE MOVES JUST SOUTH OF LOWER MICHIGAN. CANADIAN HIGH PRESSURE WILL BUILD IN FOR WEDNESDAY THROUGH THE END OF THE WEEK WITH FAIR WEATHER AND FROSTY OVERNIGHT LOWS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 347 PM EDT SUN APR 1 2012 BANDS OF LIGHT OVERRUNNING SHOWERS ACROSS NORTHERN WISCONSIN WILL BE MOVING INTO THE FORECAST AREA THROUGH THE EVENING. MOST OF THESE SHOWERS ARE LIGHT AND SOME OF THE RAIN IS EVAPORATING BEFORE REACHING THE GROUND...SO SLIGHT CHANCE POPS AND ISOLATED WORDING SHOULD COVER IT. HRRR RUC HAS HAD A GOOD HANDLE ON THIS THROUGH THE DAY...SO FOLLOWED IT FOR POPS OVERNIGHT. AFTER A BREAK IN THE PRECIP...MORE SHOWERS SHOULD MOVE IN MONDAY EVENING AS SFC LOW APPROACHES. SOME ELEVATED INSTABILITY EXISTS BUT IT IS MARGINAL...SO WENT WITH ISOLATED THUNDER CHANCES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 PM EDT SUN APR 1 2012 LOW PRESSURE IS EXPECTED TO BE SLIDING EAST OVER THE LOWER GREAT LAKES ON TUESDAY. IT STILL LOOKS LIKE SOME POTENTIAL FOR STRONG STORMS WILL HAIL...ESPECIALLY EARLY IN THE DAY...AND MAINLY ALONG AND SOUTH OF I-96. SYSTEM LOOKS A BIT SLOWER NOW...SO HAVE POPS GOING THROUGHOUT THE DAY. VERY DRY AIR FOLLOWS THE SYSTEM BY TUESDAY EVENING WITH CLEARING SKIES. COULD BE THE THREAT OF FROST BY WEDNESDAY MORNING...BUT THIS SHOULD BE PATCHY OVER INLAND AREAS AS THE PRESSURE GRADIENT SHOULD STILL CAUSE SOME MIXING THROUGH THE NIGHT. LOOKS LIKE THE BEST CHANCE OF FROST WILL COME LATE WEDNESDAY NIGHT AND LATE THURSDAY NIGHT AS THE SURFACE RIDGE AXIS WILL BE NEARBY GIVING US LIGHTER WINDS AND SINKING TEMPS TO THE LOW TO MID 30S IN MANY LOCATIONS. NEXT CHANCE OF RAIN SHOULD NOT COME UNTIL SATURDAY NIGHT INTO SUNDAY. STILL SOME UNCERTAINTY IN THIS GIVEN THE STRONG RIDGE TO OUR EAST. BUT GENERAL GUIDANCE CONSCIENCE SHOWS A FRONT COMING THROUGH ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 256 PM EDT SUN APR 1 2012 MVFR IN HAZE AND SOME CEILINGS BELOW 2000 FEET SHOULD BE GOING TO VFR BY LATE AFTERNOON. SOME LIGHT SHOWERS MOVING IN BY 00Z CONTINUING THIS EVENING BUT THESE SHOULD BE ISOLATED AND NOT AFFECT THE GENERALLY VFR CONDITIONS OVERNIGHT. && .MARINE... ISSUED AT 256 PM EDT SUN APR 1 2012 WINDS AND WAVES WILL BE RELATIVELY CALM THIS WEEK. && .HYDROLOGY... ISSUED AT 256 PM EDT SUN APR 1 2012 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...OSTUNO SHORT TERM...OSTUNO LONG TERM....JK AVIATION...OSTUNO HYDROLOGY...OSTUNO MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
336 PM EDT SUN APR 1 2012 .SYNOPSIS... ISSUED AT 1256 PM EDT SUN APR 1 2012 A FEW SHOWERS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING. ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME MONDAY NIGHT AND TUESDAY. THEN HIGH PRESSURE WILL BRING FAIR WEATHER WITH FROSTY OVERNIGHT LOWS FOR THE REST OF THE WEEK. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 1256 PM EDT SUN APR 1 2012 ADDED SLIGHT CHANCE POPS FOR LATE AFTERNOON INTO THIS EVENING. OVERRUNNING SHOWERS CURRENTLY OVER NORTHERN WISCONSIN WILL BE SINKING SOUTHEAST INTO LOWER MICHIGAN. HRRR RUC SEEMS TO HAVE A HANDLE ON THESE AND THE TIMING WAS FOLLOWED IN THE GRIDS. ALSO TWEAKED TEMPS DOWN A FEW DEGREES THIS AFTERNOON BASED ON CURRENT OBS AND STUBBORN LOW LEVEL STRATUS THIS IS SLOW TO MIX OUT GIVEN CURRENT STRONG INVERSION BELOW 700 MB. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 PM EDT SUN APR 1 2012 LOW PRESSURE IS EXPECTED TO BE SLIDING EAST OVER THE LOWER GREAT LAKES ON TUESDAY. IT STILL LOOKS LIKE SOME POTENTIAL FOR STRONG STORMS WILL HAIL...ESPECIALLY EARLY IN THE DAY...AND MAINLY ALONG AND SOUTH OF I-96. SYSTEM LOOKS A BIT SLOWER NOW...SO HAVE POPS GOING THROUGHOUT THE DAY. VERY DRY AIR FOLLOWS THE SYSTEM BY TUESDAY EVENING WITH CLEARING SKIES. COULD BE THE THREAT OF FROST BY WEDNESDAY MORNING...BUT THIS SHOULD BE PATCHY OVER INLAND AREAS AS THE PRESSURE GRADIENT SHOULD STILL CAUSE SOME MIXING THROUGH THE NIGHT. LOOKS LIKE THE BEST CHANCE OF FROST WILL COME LATE WEDNESDAY NIGHT AND LATE THURSDAY NIGHT AS THE SURFACE RIDGE AXIS WILL BE NEARBY GIVING US LIGHTER WINDS AND SINKING TEMPS TO THE LOW TO MID 30S IN MANY LOCATIONS. NEXT CHANCE OF RAIN SHOULD NOT COME UNTIL SATURDAY NIGHT INTO SUNDAY. STILL SOME UNCERTAINTY IN THIS GIVEN THE STRONG RIDGE TO OUR EAST. BUT GENERAL GUIDANCE CONSCIENCE SHOWS A FRONT COMING THROUGH ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 256 PM EDT SUN APR 1 2012 MVFR IN HAZE AND SOME CEILINGS BELOW 2000 FEET SHOULD BE GOING TO VFR BY LATE AFTERNOON. SOME LIGHT SHOWERS MOVING IN BY 00Z CONTINUING THIS EVENING BUT THESE SHOULD BE ISOLATED AND NOT AFFECT THE GENERALLY VFR CONDITIONS OVERNIGHT. && .MARINE... ISSUED AT 256 PM EDT SUN APR 1 2012 WINDS AND WAVES WILL BE RELATIVELY CALM THIS WEEK. && .HYDROLOGY... ISSUED AT 256 PM EDT SUN APR 1 2012 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...OSTUNO SHORT TERM...OSTUNO LONG TERM....JK AVIATION...OSTUNO HYDROLOGY...OSTUNO MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
256 PM EDT SUN APR 1 2012 .SYNOPSIS... ISSUED AT 1256 PM EDT SUN APR 1 2012 A FEW SHOWERS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING. ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME MONDAY NIGHT AND TUESDAY. THEN HIGH PRESSURE WILL BRING FAIR WEATHER WITH FORSTY OVERNIGHT LOWS FOR THE REST OF THE WEEK. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 1256 PM EDT SUN APR 1 2012 ADDED SLIGHT CHANCE POPS FOR LATE AFTERNOON INTO THIS EVENING. OVERRUNNING SHOWERS CURRENTLY OVER NORTHERN WISCONSIN WILL BE SINKING SOUTHEAST INTO LOWER MICHIGAN. HRRR RUC SEEMS TO HAVE A HANDLE ON THESE AND THE TIMING WAS FOLLOWED IN THE GRIDS. ALSO TWEAKED TEMPS DOWN A FEW DEGREES THIS AFTERNOON BASED ON CURRENT OBS AND STUBBORN LOW LEVEL STRATUS THIS IS SLOW TO MIX OUT GIVEN CURRENT STRONG INVERSION BELOW 700 MB. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 400 AM EDT SUN APR 1 2012 MONDAY NIGHT AND EARLY TUESDAY COULD BE ACTIVE WITH MCS ACTIVITY AS H8 THETA-E RIDGE AND LOW LEVEL JET ARE PROGGED TO BE IMPACTING THE REGION. ELEVATED INSTABILITY LOOKS PRETTY IMPRESSIVE WITH H8 LI/S AROUND -6C. DEEP LAYER SHEAR IS IN EXCESS OF 35-40 KTS AND SUSPECT A LARGE HAIL THREAT WILL EXIST WITH ANY TSTM CELLS/CLUSTERS TRACKING SOUTHEAST THROUGH THE AREA. THE NAM/GFS SHOW THE SFC FRONT/TROUGH EXITING THE REGION BY 18Z TUESDAY BUT THE EURO IS SLOWER AND SUGGESTS A CONVECTIVE THREAT LINGERING ALL DAY TUESDAY. WEDNESDAY THROUGH SATURDAY IS DOMINATED BY A LARGE/DRY AREA OF HIGH PRESSURE. THIS FEATURE WILL BRING A THREAT OF FROST EACH NIGHT... WITH SUNNY/PLEASANT CONDITIONS AND HIGHS IN THE 50S/60S EXPECTED FOR THE DAYS. DIURNAL TEMP SWINGS SHOULD BE RATHER LARGE DUE TO THE DRY AIR MASS AND MAINLY CLEAR SKIES. CONSIDERING THAT THE LOW LEVEL FLOW SHOULD BE PREDOMINATELY NORTHEASTERLY... WOULD EXPECT THE WARMEST HIGH TEMPERATURES TO BE IN THE WRN HALF OF THE CWFA DURING THE MID TO LATE WEEK PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 256 PM EDT SUN APR 1 2012 MVFR IN HAZE AND SOME CEILINGS BELOW 2000 FEET SHOULD BE GOING TO VFR BY LATE AFTERNOON. SOME LIGHT SHOWERS MOVING IN BY 00Z CONTINUING THIS EVENING BUT THESE SHOULD BE ISOLATED AND NOT AFFECT THE GENERALLY VFR CONDITIONS OVERNIGHT. && .MARINE... ISSUED AT 256 PMEDT SUN APR 1 2012 WINDS AND WAVES WILL BE RELATIVELY CALM THIS WEEK. && .HYDROLOGY... ISSUED AT 256 PM EDT SUN APR 1 2012 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...OSTUNO SHORT TERM...OSTUNO LONG TERM....MEADE AVIATION...OSTUNO HYDROLOGY...OSTUNO MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1257 PM EDT SUN APR 1 2012 .SYNOPSIS... ISSUED AT 1256 PM EDT SUN APR 1 2012 A FEW SHOWERS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING. ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME MONDAY NIGHT AND TUESDAY. THEN HIGH PRESSURE WILL BRING FAIR WEATHER WITH FORSTY OVERNIGHT LOWS FOR THE REST OF THE WEEK. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 1256 PM EDT SUN APR 1 2012 ADDED SLIGHT CHANCE POPS FOR LATE AFTERNOON INTO THIS EVENING. OVERRUNNING SHOWERS CURRENTLY OVER NORTHERN WISCONSIN WILL BE SINKING SOUTHEAST INTO LOWER MICHIGAN. HRRR RUC SEEMS TO HAVE A HANDLE ON THESE AND THE TIMING WAS FOLLOWED IN THE GRIDS. ALSO TWEAKED TEMPS DOWN A FEW DEGREES THIS AFTERNOON BASED ON CURRENT OBS AND STUBBORN LOW LEVEL STRATUS THIS IS SLOW TO MIX OUT GIVEN CURRENT STRONG INVERSION BELOW 700 MB. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 400 AM EDT SUN APR 1 2012 MONDAY NIGHT AND EARLY TUESDAY COULD BE ACTIVE WITH MCS ACTIVITY AS H8 THETA-E RIDGE AND LOW LEVEL JET ARE PROGGED TO BE IMPACTING THE REGION. ELEVATED INSTABILITY LOOKS PRETTY IMPRESSIVE WITH H8 LI/S AROUND -6C. DEEP LAYER SHEAR IS IN EXCESS OF 35-40 KTS AND SUSPECT A LARGE HAIL THREAT WILL EXIST WITH ANY TSTM CELLS/CLUSTERS TRACKING SOUTHEAST THROUGH THE AREA. THE NAM/GFS SHOW THE SFC FRONT/TROUGH EXITING THE REGION BY 18Z TUESDAY BUT THE EURO IS SLOWER AND SUGGESTS A CONVECTIVE THREAT LINGERING ALL DAY TUESDAY. WEDNESDAY THROUGH SATURDAY IS DOMINATED BY A LARGE/DRY AREA OF HIGH PRESSURE. THIS FEATURE WILL BRING A THREAT OF FROST EACH NIGHT... WITH SUNNY/PLEASANT CONDITIONS AND HIGHS IN THE 50S/60S EXPECTED FOR THE DAYS. DIURNAL TEMP SWINGS SHOULD BE RATHER LARGE DUE TO THE DRY AIR MASS AND MAINLY CLEAR SKIES. CONSIDERING THAT THE LOW LEVEL FLOW SHOULD BE PREDOMINATELY NORTHEASTERLY... WOULD EXPECT THE WARMEST HIGH TEMPERATURES TO BE IN THE WRN HALF OF THE CWFA DURING THE MID TO LATE WEEK PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 750 AM EDT SUN APR 1 2012 MVFR CONDITIONS DUE TO 3-5 MILE VSBYS IN LIGHT FOG WERE PRESENT EARLY THIS MORNING. CIGS WERE MOSTLY 4-6K FEET WITH A FEW LIGHT RAIN SHOWERS OR VIRGA/SPRINKLES DOTTING THE REGION. DRIER AIR IS EXPECTED TO FLOW INTO THE REGION TODAY FROM NORTH TO SOUTH AS A WEAK SFC FRONT PASSES THROUGH AND SETTLES SOUTH OF MI THIS AFTERNOON. VSBYS ARE EXPECTED TO INCREASE ABOVE 6SM WITH THE 4-6K CLOUD DECK SCATTERING OUT AS THE FRONT COMES THROUGH AND WINDS SHIFT NORTHERLY AROUND 8 KTS. OPTED TO LEAVE THE MENTION OF TS/CB OUT OF THE I-94 CORRIDOR TAF SITES SINCE THE ACTIVITY CURRENTLY OVER CHICAGO IS SLIDING SE AND SHOULD NOT BE A FACTOR. ANY REDEVELOPMENT LATER TODAY SHOULD BE JUST SOUTH OF THE MI BORDER NEAR THE SFC FRONT. && .MARINE... ISSUED AT 400 AM EDT SUN APR 1 2012 WINDS/WAVES WILL REMAIN UNDER SMALL CRAFT ADVISORY CRITERIA TODAY INTO EARLY NEXT WEEK. && .HYDROLOGY... ISSUED AT 400 AM EDT SUN APR 1 2012 NO HYDRO CONCERNS DUE TO LITTLE IF ANY PCPN TODAY... LIGHT QPF AMOUNTS MONDAY NIGHT/TUE FOLLOWED BY DRY WX MID TO LATE WEEK. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...OSTUNO SHORT TERM...OSTUNO LONG TERM....MEADE AVIATION...MEADE HYDROLOGY...LAURENS MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1023 AM MDT SUN APR 1 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH TUESDAY... UPDATED THE FORECAST TO LOWER THE CHANCE OF RAIN PER THE CURRENT RADAR AND THE HRRR MODEL FOR THIS MORNING AND AFTERNOON. ALSO LOWERED SKY COVER FOR THE AFTERNOON. REST OF THE SHORT TERM FORECAST IS ON TRACK. RSMITH PREVIOUS DISCUSSION...SPLITTING UPPER TROF MOVING ACROSS THE WEST COAST...WILL BE FORMING A CUT OFF LOW OVER THE FOUR CORNERS WHILE THE NORTHERN PORTION LIFTS ACROSS MONTANA AND INTO CENTRAL CANADA THROUGH MONDAY. COLD FRONT ALONG THE WESTERN BORDER OF CWA WITH SHOWERS AND A FEW THUNDERSTORMS STREAMING NORTHWARD ACROSS CENTRAL MONTANA. WEAK SURFACE LOW DEVELOPING OVER SOUTHEAST MONTANA EXPECTED TO PUSH TO THE NORTHEAST TODAY WHILE COLD FRONT MOVES ACROSS EASTERN MONTANA. AREA OF SHOWERS AND THUNDERSTORMS ALSO EXPECTED TO BE LIFTING NORTH SO MAINLY WILL BE AFFECTING THE FAR WESTERN ZONES THIS MORNING. STRONG COLD AIR ADVECTION BEHIND THE FRONT ALONG WITH TIGHTENING PRESSURE GRADIENT WILL RESULT IN STRONG WEST WINDS BY AFTERNOON PERSISTING INTO THE EVENING. AS SHOWERS MOVE NORTH AND WIND INCREASE...RELATIVE HUMIDITY IS EXPECTED TO DROP IN THE AFTERNOON... BRINGING ON CRITICAL FIRE WEATHER CONDITIONS. COLD AIR ADVECTION CONTINUES THROUGH SUNDAY NIGHT WITH THE UPPER TROF MOVING ACROSS THE STATE. THIS WILL KEEP WINDS FROM DIMINISHING COMPLETELY. BY MONDAY MORNING RIDGE BEGINS REBOUNDING OVER THE NORTHERN ROCKIES BUT COLD AIR WILL LINGER OVER EASTERN MONTANA. WINDS WILL KICK UP AGAIN IN THE AFTERNOON WITH GOOD MIXING EXPECTED. UPPER RIDGE SPREADS OVER THE NORTHERN PLAINS ON TUESDAY WITH WARMER AIR PUSHING INTO THE TREASURE STATE. HIGH PRESSURE MOVES INTO THE CENTRAL PLAINS WITH WINDS GOING AROUND TO THE SOUTH AND WEAK LEE TROF DEVELOPING IN CENTRAL MONTANA. EBERT .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... SYNOPTIC SET UP AS OF TUESDAY AFTERNOON... TO THE EAST A COLD AIR POOL OVER THE HUDSON BAY IS DIVING INTO THE GREAT LAKES. A RIDGE RIDES FROM DEATH VALLEY THROUGH CENTRAL MONTANA AND UP INTO NORTHERN ALBERTA. A LONG WAVE TROUGH STRETCHES FROM YUKON TO THE COAST OF BRITISH COLUMBIA DOWN TO OFF THE COAST OF NORTHERN CALIFORNIA. FURTHER UP STREAM A SMALL RIDGE/TROUGH COMBO LIES JUST SOUTH OF THE ALEUTIANS. TUESDAY NIGHT THROUGH WEDNESDAY... RIDGE WILL BE IN FULL CONTROL OVER THE AREA AND SHOULD PRECLUDE ANY SHOWERS WITH A SEMI STABLE ATMOSPHERE. ANTICIPATE PARTLY CLOUDY TO CLEAR SKIES. WEDNESDAY NIGHT THROUGH FRIDAY... OFF SHORE TROUGH WILL MOVE OVER THE INTERMOUNTAIN WEST AND BEGIN IMPACTING THE CENTRAL MONTANA. INITIALLY THUNDERSHOWERS WILL BE POSSIBLE DUE TO THE RIDGE BREAKING DOWN AND LEE SIDE MOUNTAIN TROUGH SETTING UP THURSDAY AFTERNOON. SOUTHWEST FLOW WILL ALSO BEING PUMPING MID LEVEL MOISTURE AND MESOSCALE DISTURBANCES INTO THE REGION AS WELL. THURSDAY NIGHT INTO FRIDAY A SURFACE LOW WILL BEGIN TO FORM AND DRAG IN COLD AIR BEHIND THE SYSTEM. THE CONTRAST WILL PROVIDE LIFT BUT SHOULD TURN IT INTO A STRATIFORM EVENT BY FRIDAY. FRIDAY NIGHT ONWARD... MODELS ARE SWINGING AROUND A BIT AND CONFIDENCE IS BELOW AVERAGE. WHERE AT FIRST WENT WITH AND EC/GEM 12Z BLEND THE NEW CONSENSUS IS GFS/EC 00Z BLEND. GOING PREDOMINATELY PERSISTENCE AND USING SLIGHT BLENDS. SURFACE LOW PREVIOUSLY WAS KICKED OUT TO THE EAST EARLY BUT NOW HOLDS ON OVER SOUTHERN CANADA BEFORE EXITING SATURDAY AFTERNOON. REGION LOOKS TO PUSH FOR ZONAL SO MODERATED TEMPERATURES OUT BY BLUNTING ANY COLD OR WARM PUSHES. GAH && .AVIATION... VFR WITH ISOLATED SHOWERS THIS MORNING ACROSS THE TERMINALS. THE WINDS WILL BE OUT OF THE EAST AT 5 TO 15 KNOTS DURING THE EARLY MORNING. BY LATE MORNING TO MIDDAY A COLD FRONT WILL BACK THE WINDS TO THE NORTHWEST AND INCREASE THEM TO AROUND 20 KTS GUSTING TO 30 KTS. KGDV TERMINAL AWOS EQUIPMENT IS HAVING PROBLEMS WITH VISIBILITY AND OCCASIONAL CEILINGS IN METARS. AMENDMENTS WILL BE LIMITED TO WINDS ONLY. GAH && .FIRE WEATHER... A COLD FRONT WILL CROSS EASTERN MONTANA THIS MORNING WITH SLIGHTLY COOLER BUT WINDIER CONDITIONS EXPECTED. RH WILL AGAIN DIP INTO THE LOWER 20S DRIVING ANOTHER ROUND OF CRITICAL FIRE WEATHER CONDITIONS ACROSS ALL OF NORTHEAST MONTANA. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR MTZ120-122-134>137. LAKE WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR FORT PECK LAKE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
656 PM EDT SUN APR 1 2012 .SYNOPSIS... HIGH PRESSURE NORTH OF LAKE SUPERIOR WILL BUILD SOUTHEAST INTO THE AREA TONIGHT THEN SHIFT OFF TO THE EAST TUESDAY. A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE REGION LATE TUESDAY THEN HIGH PRESSURE WILL SPREAD SOUTHEAST INTO THE AREA BY WEDNESDAY NIGHT AND BECOMES NEARLY STATIONARY INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... SHOWERS AND A FEW EMBEDDED THUNDERSTORMS CONTINUE ALONG A CORRIDOR THROUGH THE CENTRAL PORTION OF THE FORECAST AREA. THIS IS WELL ALIGNED WITH THE GFS MODEL. THE GFS SHOWS A SMALL AREA OF POSITIVE VORTICITY ADVECTION AND ASSOCIATED VORTICITY MAXIMUM MOVING SOUTHEAST INTO THE AREA. A SWATH OF MOISTURE IS ALSO MOVING SOUTHEAST INTO THE AREA AND HENCE THE PRECIPITATION. THE WHOLE AREA WILL MOVE SOUTHWEST WITH TIME AS 500 MB LOW PRESSURE SYSTEM RETROGRADES SOUTHWEST INTO THE AREA. THIS WILL HELP TO AMPLIFY THE 500 MB RIDGE WEST OF THE FORECAST AREA FORCING AXIS OF PRECIPITATION TO SHIFT WEST AS WELL. I WILL KEEP A MENTION OF THUNDER JUST IN CASE A RENEGADE CELL DEVELOPS. I THINK THE THREAT FOR THUNDER WILL CONTINUE TO DIMINISH AS THE SUN SETS THIS EVENING. COLD AIR ADVECTION CONTINUES TO PUSH SOUTH AND HAS REACHED THE EXTREME NORTHEAST PORTIONS OF THE FORECAST AREA BEHIND THE COLD FRONT. CURRENT FORECAST TEMPERATURES LOOK REASONABLE AT THIS TIME. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/... THE RIDGE OF HIGH PRESSURE OVER THE AREA SHOULD KEEP CONDITIONS DRY INTO MON EVENING. A WEAKENING LOW ALONG A COLD FRONT WILL CROSS THE AREA TUESDAY. MODELS HAVE BACKED DOWN ON OVERALL QPF FOR THIS EVENT BUT STILL THINK MOST PLACES WILL SEE SOMETHING AT SOME POINT FROM LATE MON NIGHT INTO TUE EVENING. AIRMASS CONTINUES TO LOOK UNSTABLE ENOUGH FOR TSRA. ANOTHER HIGH RIDGES SOUTH INTO THE CWA TUE NIGHT THROUGH WED BRINGING DRIER AIR AND SHOULD END MOST OF THE SHRA THREAT FROM NORTH TO SOUTH TUE EVENING. RIDGING REMAINS OVER AREA AND SHOULD KEEP DRY WEATHER IN PLACE THROUGH THU NIGHT. HOWEVER...LATEST GFS NOW TRYING TO BRING CUTOFF UPPER LOW CLOSER TO SW OH SO THIS WILL NEED TO BE WATCHES NEXT FEW MODEL RUNS TO SEE IF THIS WILL TURN INTO A TYPICAL SPRINGTIME UPPER LOW THAT FINDS A HOME IN OHIO. WILL HAVE TO WATCH FOR FROST OR FREEZE THREAT FOR WED AND THU NIGHT BUT RIGHT NOW LOOKS LIKE NORTH TO NE WINDS WILL STAY UP ENOUGH TO KEEP FROST AWAY SO REAL CONCERN WILL BE WHERE TEMPS MAY TRY TO DROP TO 32 OR LESS IN THE INLAND EAST THESE NIGHTS. SOME MOISTURE DROPS SOUTH INTO THE SNOWBELT AREA FOR LATER WED NIGHT THROUGH THU NIGHT AND COULD RESULT IN ENOUGH LAKE EFFECT CLOUDS TO KEEP TEMPS FROM GETTING DOWN TO 32...THEREFORE A LOT OF UNCERTAINTY AS TO HOW LOW TEMPS WILL GO WED AND THU NIGHT. && .LONG TERM /THURSDAY THROUGH SUNDAY/... THE FORECASTS REMAIN CONSISTENT WITH A RIDGE ACROSS THE AREA FOR FRIDAY AND SATURDAY. HOWEVER...A SYSTEM IS MOVING JUST TO THE SOUTH OF THE REGION...THIS WILL HAVE TO BE WATCHED. AT THIS TIME IT SEEMS LIKE THE RIDGE WILL BE STRONG ENOUGH TO KEEP IT SOUTH. FOR SUNDAY AND SUNDAY NIGHT A FRONT WILL BE MOVING THROUGH. TIMING IS ON THE EDGE. DID INCLUDE A CHANCE WEST SUNDAY AND MUCH OF THE AREA SUNDAY NIGHT. TEMPERATURES WILL MODERATE AS THE RIDGE MOVES SLOWLY EAST. WENT CLOSE TO HPC GUIDANCE FOR TEMPERATURE. DEPENDING ON THE STRENGTH OF THE NORTHERLY FLOW IT WILL HELP KEEP TEMPERATURES COOLER ALONG THE LAKESHORE AT TIMES. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... FRONTAL SYSTEMS AND LOW HEADED TOWARD THE FORECAST AREA FOR THE AFTERNOON AND EVENING. THE FRONTS SEEM DIFFUSE SO THE WINDS WILL PROBABLY JUST SHIFT ONCE THE LOW MOVES THROUGH. ATTM NOT THAT EXCITED ABOUT A LOT OF THUNDERSTORM ACTIVITY AS MOST OF THE UNSTABLE AIR WILL BE NEAR AND SOUTH OF THE SOUTHERN PORTION OF THE FORECAST AREA. THE CLOUDS WILL BE IN AND OUT THROUGH MID AFTERNOON BUT THE TREND WILL BE FOR CLOUDS MOVING BACK IN FROM THE NORTHWEST. THE WINDS WILL SHIFT FROM THE SOUTHWEST TO NORTHWEST AND THEN TO NORTHEAST BY THIS EVENING. AS THIS HAPPENS AREAS OF MVFR CEILINGS AND MAY BE EVEN SOME IFR THINGS WILL DEVELOP. AT THIS TIME IT LOOKS LIKE IT SHOULD BE DRY TONIGHT. THE HRRR MODEL IS INDICATING SOME SHOWERS...BUT ATTM THEY ARE NOT REACHING THE GROUND. THE FORECAST IS FOR THE CLOUDS TO MOVE OUT OF THE REGION BY DAYBREAK MONDAY. CONFIDENCE IN THIS IS FAIR. .OUTLOOK...NON VFR POSSIBLE TUESDAY AND TUESDAY EVENING. && .MARINE... A LOW WILL BE MOVING ACROSS NORTHERN OHIO AND NORTHWEST PA THROUGH THIS EVENING AND THIS WILL BRING THE WINDS AROUND FROM THE SOUTHWEST TO NORTHEAST BETWEEN DARK AND MIDNIGHT. AS THIS HAPPENS THE WINDS AND WAVES WILL PICK UP...THUS ISSUED A SMALL CRAFT ADVISORY FOR LAKE ERIE STARTING AT 8 PM AND LASTING UNTIL NOON MONDAY. AFTER THAT A RIDGE WILL BUILD IN BRIEFLY FOR MONDAY EVENING DECREASING THE WINDS AND WAVES AND THEN IT WILL MOVE EAST. FOR LATE TUESDAY THROUGH FRIDAY A THREAT FOR SMALL CRAFT ADVISORIES AT TIMES WILL OCCUR. ANOTHER LOW WILL MOVE ACROSS OHIO LATE TUESDAY AND THIS IN COMBINATION WITH A RIDGE BUILDING BACK IN THE WINDS AND WAVES COULD BE CLOSE TO SMALL CRAFT ADVISORY CRITERIA. ON FRIDAY ANOTHER LOW WILL MOVE THROUGH THE TENNESSEE VALLEY AND THIS IN COMBINATION WITH THE RIDGE OVER LAKE ERIE WILL CAUSE A NORTHEAST FLOW AND IT COULD BE STRONG ENOUGH TO CAUSE WAVES TO BE 3 TO 5 FEET. ALL THIS WILL BE WATCHED CLOSELY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT MONDAY FOR LEZ142>149. && $$ SYNOPSIS...ADAMS NEAR TERM...LOMBARDY SHORT TERM...ADAMS LONG TERM...KIELTYKA AVIATION...KIELTYKA MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
325 PM EDT SUN APR 1 2012 .SYNOPSIS... HIGH PRESSURE NORTH OF LAKE SUPERIOR WILL BUILD SOUTHEAST INTO THE AREA TONIGHT THEN SHIFT OFF TO THE EAST TUESDAY. A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE REGION LATE TUESDAY THEN HIGH PRESSURE WILL SPREAD SOUTHEAST INTO THE AREA BY WEDNESDAY NIGHT AND BECOMES NEARLY STATIONARY INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... DRIER AIR PUSHING SOUTH BEHIND THE COLD FRONT WILL PUSH THE THREAT OF SHRA SOUTH OF THE CWA DURING THE EVENING OR CERTAINLY BY 1 TO 2 AM. SOME LAKE EFFECT CLOUDS MAY OCCUR BUT OVERALL LAKE EFFECT CONDITIONS DO NOT APPEAR STRONG ENOUGH TO OFFSET STRONG SUBSIDENCE OCCURRING AS HIGH PRESSURE RIDGES SOUTH INTO THE AREA. ANOTHER COOL NIGHT WITH TEMPS IN THE EAST CLOSE TO FREEZING POINT BY DAYBREAK. HOWEVER...THINK JUST ENOUGH WIND WILL CONTINUE THROUGH THE NIGHT TO KEEP FROST FROM FORMING SO NO ADVISORY PLANNED. && .SHORT TERM /MONDAY THROUGH THURSDAY NIGHT/... THE RIDGE OF HIGH PRESSURE OVER THE AREA SHOULD KEEP CONDITIONS DRY INTO MON EVENING. A WEAKENING LOW ALONG A COLD FRONT WILL CROSS THE AREA TUESDAY. MODELS HAVE BACKED DOWN ON OVERALL QPF FOR THIS EVENT BUT STILL THINK MOST PLACES WILL SEE SOMETHING AT SOME POINT FROM LATE MON NIGHT INTO TUE EVENING. AIRMASS CONTINUES TO LOOK UNSTABLE ENOUGH FOR TSRA. ANOTHER HIGH RIDGES SOUTH INTO THE CWA TUE NIGHT THROUGH WED BRINGING DRIER AIR AND SHOULD END MOST OF THE SHRA THREAT FROM NORTH TO SOUTH TUE EVENING. RIDGING REMAINS OVER AREA AND SHOULD KEEP DRY WEATHER IN PLACE THROUGH THU NIGHT. HOWEVER...LATEST GFS NOW TRYING TO BRING CUTOFF UPPER LOW CLOSER TO SW OH SO THIS WILL NEED TO BE WATCHES NEXT FEW MODEL RUNS TO SEE IF THIS WILL TURN INTO A TYPICAL SPRINGTIME UPPER LOW THAT FINDS A HOME IN OHIO. WILL HAVE TO WATCH FOR FROST OR FREEZE THREAT FOR WED AND THU NIGHT BUT RIGHT NOW LOOKS LIKE NORTH TO NE WINDS WILL STAY UP ENOUGH TO KEEP FROST AWAY SO REAL CONCERN WILL BE WHERE TEMPS MAY TRY TO DROP TO 32 OR LESS IN THE INLAND EAST THESE NIGHTS. SOME MOISTURE DROPS SOUTH INTO THE SNOWBELT AREA FOR LATER WED NIGHT THROUGH THU NIGHT AND COULD RESULT IN ENOUGH LAKE EFFECT CLOUDS TO KEEP TEMPS FROM GETTING DOWN TO 32...THEREFORE A LOT OF UNCERTAINTY AS TO HOW LOW TEMPS WILL GO WED AND THU NIGHT. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE FORECASTS REMAIN CONSISTENT WITH A RIDGE ACROSS THE AREA FOR FRIDAY AND SATURDAY. HOWEVER...A SYSTEM IS MOVING JUST TO THE SOUTH OF THE REGION...THIS WILL HAVE TO BE WATCHED. AT THIS TIME IT SEEMS LIKE THE RIDGE WILL BE STRONG ENOUGH TO KEEP IT SOUTH. FOR SUNDAY AND SUNDAY NIGHT A FRONT WILL BE MOVING THROUGH. TIMING IS ON THE EDGE. DID INCLUDE A CHANCE WEST SUNDAY AND MUCH OF THE AREA SUNDAY NIGHT. TEMPERATURES WILL MODERATE AS THE RIDGE MOVES SLOWLY EAST. WENT CLOSE TO HPC GUIDANCE FOR TEMPERATURE. DEPENDING ON THE STRENGTH OF THE NORTHERLY FLOW IT WILL HELP KEEP TEMPERATURES COOLER ALONG THE LAKESHORE AT TIMES. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... FRONTAL SYSTEMS AND LOW HEADED TOWARD THE FORECAST AREA FOR THE AFTERNOON AND EVENING. THE FRONTS SEEM DIFFUSE SO THE WINDS WILL PROBABLY JUST SHIFT ONCE THE LOW MOVES THROUGH. ATTM NOT THAT EXCITED ABOUT A LOT OF THUNDERSTORM ACTIVITY AS MOST OF THE UNSTABLE AIR WILL BE NEAR AND SOUTH OF THE SOUTHERN PORTION OF THE FORECAST AREA. THE CLOUDS WILL BE IN AND OUT THROUGH MID AFTERNOON BUT THE TREND WILL BE FOR CLOUDS MOVING BACK IN FROM THE NORTHWEST. THE WINDS WILL SHIFT FROM THE SOUTHWEST TO NORTHWEST AND THEN TO NORTHEAST BY THIS EVENING. AS THIS HAPPENS AREAS OF MVFR CEILINGS AND MAY BE EVEN SOME IFR THINGS WILL DEVELOP. AT THIS TIME IT LOOKS LIKE IT SHOULD BE DRY TONIGHT. THE HRRR MODEL IS INDICATING SOME SHOWERS...BUT ATTM THEY ARE NOT REACHING THE GROUND. THE FORECAST IS FOR THE CLOUDS TO MOVE OUT OF THE REGION BY DAYBREAK MONDAY. CONFIDENCE IN THIS IS FAIR. .OUTLOOK...NON VFR POSSIBLE TUESDAY AND TUESDAY EVENING. && .MARINE... A LOW WILL BE MOVING ACROSS NORTHERN OHIO AND NORTHWEST PA THROUGH THIS EVENING AND THIS WILL BRING THE WINDS AROUND FROM THE SOUTHWEST TO NORTHEAST BETWEEN DARK AND MIDNIGHT. AS THIS HAPPENS THE WINDS AND WAVES WILL PICK UP...THUS ISSUED A SMALL CRAFT ADVISORY FOR LAKE ERIE STARTING AT 8 PM AND LASTING UNTIL NOON MONDAY. AFTER THAT A RIDGE WILL BUILD IN BRIEFLY FOR MONDAY EVENING DECREASING THE WINDS AND WAVES AND THEN IT WILL MOVE EAST. FOR LATE TUESDAY THROUGH FRIDAY A THREAT FOR SMALL CRAFT ADVISORIES AT TIMES WILL OCCUR. ANOTHER LOW WILL MOVE ACROSS OHIO LATE TUESDAY AND THIS IN COMBINATION WITH A RIDGE BUILDING BACK IN THE WINDS AND WAVES COULD BE CLOSE TO SMALL CRAFT ADVISORY CRITERIA. ON FRIDAY ANOTHER LOW WILL MOVE THROUGH THE TENNESSEE VALLEY AND THIS IN COMBINATION WITH THE RIDGE OVER LAKE ERIE WILL CAUSE A NORTHEAST FLOW AND IT COULD BE STRONG ENOUGH TO CAUSE WAVES TO BE 3 TO 5 FEET. ALL THIS WILL BE WATCHED CLOSELY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO NOON EDT MONDAY FOR LEZ142>149. && $$ SYNOPSIS...ADAMS NEAR TERM...TK SHORT TERM...ADAMS LONG TERM...KIELTYKA AVIATION...KIELTYKA MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
150 PM EDT SUN APR 1 2012 .SYNOPSIS... WEAK LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES TODAY. A WARM FRONT WILL MOVE INTO THE AREA AHEAD OF THE LOW...FOLLOWED QUICKLY BY A COLD FRONT. HIGH PRESSURE OVER ONTARIO WILL EXTEND ACROSS THE EASTERN GREAT LAKES INTO THE OHIO VALLEY TONIGHT AND MONDAY. THE HIGH WILL MOVE EAST TUESDAY AND ALLOW LOW PRESSURE TO DRIFT IN FROM THE WEST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... GENERAL THINKING FROM PREVIOUS UPDATE (BELOW) REMAINS ON TRACK. ONLY CHANGES ARE FOR CURRENT CONDITIONS AND BLENDING. COLD FRONT SAGGING SOUTH ACROSS MUCH OF THE CWA THIS AFTERNOON INTO EARLY EVENING STILL WELL NORTH OF THE CWA SO THINK MORE OF A SOUTH TO SW FLOW SHOULD DOMINATE UNTIL AT LEAST 19Z TO 20Z THEN SHIFT TO NW AND NORTH SHOULD START NEAR LERI AND PUSH SOUTH REST OF AFTERNOON AND EVENING. AS AIRMASS DESTABILIZES MORE WITH HEAT OF THE DAY EXPECT MORE CONVECTION TO DEVELOP SO AS FRONT PUSHES THROUGH STILL SEE A GOOD CHANCE FOR MOST AREAS. COULD BE SOME STRONG STORMS IN THE FAR SW BUT THE SEVERE THREAT SHOULD STAY SW OF THE AREA WHERE MORE UNSTABLE AIR EXISTS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... 00Z THIS EVENING THE COLD FRONT SHOULD BE ACROSS SOUTHERN OHIO WITH DRY AIR MOVING INTO THE AREA FROM THE NORTH. ENDED PRECIP QUICKLY ALTHOUGH DID HOLD ONTO CHANCE POPS...HIGHEST SOUTH...THIS EVENING TO COVER ANY LINGERING PRECIP. BY 03Z HOWEVER NAM SHOWS DRY AIR IN PLACE AND POSITIVE CAPES WELL SOUTH OF THE AREA. OVERNIGHT HIGH PRESSURE WILL CONTINUE TO BUILD IN. PAST TWO HIGHS HAVE NOT MANAGED TO CLEAR OUT THE STRATUS BUT BUFKIT SHOWS DRIER AIR WILL BE MOVING IN SO WILL GO AHEAD AND BUY INTO THE CLEARING. MONDAY...HIGH PRESSURE WILL CONTINUE OVER THE AREA ALTHOUGH WINDS WILL BE FROM THE NORTH/NORTHEAST. EXPECT LAKESHORE AREAS TO REMAIN CHILLY VS INLAND. ALSO EXPECT A SIZABLE TEMP GRADIENT FROM NORTHEAST TO SOUTHWEST WITH 850MB TEMPS 0 TO 2C OVER ERIE IN THE AFTERNOON AND 8 TO 10C OVER FDY. TUESDAY THE HIGH WILL MOVE EAST AND LOW PRESSURE WILL MOVE IN FROM THE WEST. 850MB TEMPS RISE TO 14C WITH ALL OF THE AREA IN THE WARM SECTOR AHEAD OF THE APPROACHING COLD FRONT. EXPECTING A MILD AFTERNOON ALTHOUGH WITH CAPES SHOWN ON THE NAM AROUND 2000 J/KG WILL LIKELY BE STORMY SO WEST ABOVE GUIDANCE WITH LIKELY POPS FOR THUNDERSTORMS. MUCH DRIER AIR MOVES IN DURING THE EVENING POST COLD FRONT AND BY MORNING...IF SKIES CLEAR COULD SEE ANOTHER ROUND OF FROST. WEDNESDAY AND WED NIGHT WILL BE DRY WITH NEAR NORMAL TEMPS. && .LONG TERM /THURSDAY THROUGH SATURDAY/... GFS AND ECMWF HAVE INCREASED IN SIMILARITY OVER THE PAST DAY TO BRING STRONGER CONFIDENCE IN SHOWING HIGH PRESSURE OVER THE GREAT LAKES WILL DOMINATE ACROSS THE FORECAST AREA THROUGH THE SECOND HALF OF THE UPCOMING WEEK. THIS WILL ALLOW FOR DRY CONDITIONS AND SEASONABLE TEMPERATURES. AS PREVIOUSLY MENTIONED...THE NORTH FLOW OFF THE LAKE OR DEVELOPING LAKE BREEZES WITH A LIGHT GRADIENT...WILL CAUSE FOR AT LEAST SEASONABLE TEMPERATURES ACROSS THE INTERIOR BUT COOLER MAXES ALONG THE LAKESHORE. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... FRONTAL SYSTEMS AND LOW HEADED TOWARD THE FORECAST AREA FOR THE AFTERNOON AND EVENING. THE FRONTS SEEM DIFFUSE SO THE WINDS WILL PROBABLY JUST SHIFT ONCE THE LOW MOVES THROUGH. ATTM NOT THAT EXCITED ABOUT A LOT OF THUNDERSTORM ACTIVITY AS MOST OF THE UNSTABLE AIR WILL BE NEAR AND SOUTH OF THE SOUTHERN PORTION OF THE FORECAST AREA. THE CLOUDS WILL BE IN AND OUT THROUGH MID AFTERNOON BUT THE TREND WILL BE FOR CLOUDS MOVING BACK IN FROM THE NORTHWEST. THE WINDS WILL SHIFT FROM THE SOUTHWEST TO NORTHWEST AND THEN TO NORTHEAST BY THIS EVENING. AS THIS HAPPENS AREAS OF MVFR CEILINGS AND MAY BE EVEN SOME IFR THINGS WILL DEVELOP. AT THIS TIME IT LOOKS LIKE IT SHOULD BE DRY TONIGHT. THE HRRR MODEL IS INDICATING SOME SHOWERS...BUT ATTM THEY ARE NOT REACHING THE GROUND. THE FORECAST IS FOR THE CLOUDS TO MOVE OUT OF THE REGION BY DAYBREAK MONDAY. CONFIDENCE IN THIS IS FAIR. .OUTLOOK...NON VFR POSSIBLE TUESDAY AND TUESDAY EVENING. && .MARINE... SFC HIGH PRESSURE OVER THE LAKE THIS MORNING WILL MOVE TO THE EAST THIS MORNING AS A LOW PRESSURE AND COLD FRONT CROSS THE LAKE THIS AFTERNOON AND EVENING. THIS WILL SHIFT WINDS FROM SOUTHERLY TODAY TO NORTH AND NORTHEAST TONIGHT. WILL HAVE TO WATCH FOR SMALL CRAFT ADVISORY POTENTIAL...BUT LOOKS LIKE THE GRADIENT WILL BE LIGHT ENOUGH TO KEEP WINDS AROUND 15KT AND WAVES AROUND 3 FEET. THE NEXT LOW PRESSURE EXPECTED TO MOVE ACROSS THE LAKE ON TUESDAY. HOWEVER...AGAIN THIS SYSTEM LOOKS BE ON THE WEAKER SIDE ALSO. WHILE WINDS WILL SHIFT FROM SOUTH TO NORTHERLY BETWEEN TUESDAY MORNING AND TUESDAY NIGHT...CONDITIONS MAY ALSO REMAIN JUST BELOW SMALL CRAFT CRITERIA. HIGH PRESSURE TO THE NORTH WILL DOMINATE OVER THE LAKE BY WEDNESDAY AND PERSIST THROUGH THE WEEK. WITH HIGH PRESSURE RIDGING SOUTH OVER THE LAKE DURING THE SECOND HALF OF THE WEEK...THE IS THE CHANCE FOR A PERIOD OF SMALL CRAFT CONDITIONS WEDNESDAY OR THURSDAY BEFORE IT BECOMES SETTLED OVER THE LAKE FOR THE END OF THE WEEK. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...ADAMS SHORT TERM...TK LONG TERM...ABE AVIATION...ADAMS MARINE...ABE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
135 PM EDT SUN APR 1 2012 .SYNOPSIS... A FRONTAL BOUNDARY WILL DROP SOUTH INTO THE OHIO VALLEY TODAY OFFERING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS. THIS FRONT WILL PUSH INTO THE TENNESSEE VALLEY WITH SURFACE HIGH PRESSURE PROVIDING A TEMPORARY DRY PERIOD ON MONDAY. THIS FRONT IS EXPECTED TO RETURN BRINGING ADDITIONAL THUNDERSTORMS MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /UNTIL 9 PM THIS EVENING/... DECAYING MCS WILL BRING A CHANCE FOR SHOWERS MAINLY WEST OF I-75 THROUGH THE LATE MORNING. GRADUAL CLEARING BEHIND THIS FEATURE...COMBINED WITH AMPLE WARM/MOISTURE ADVECTION FROM THE SOUTHWEST ASSOCIATED WITH A WARM FRONT WILL LEAD TO TEMPERATURES INTO THE LOW TO MID 70S ACROSS THE MAJORITY OF THE AREA BY LATE THIS AFTERNOON. NORTHWESTERLY FLOW ALOFT WILL INTENSIFY LATER TODAY AROUND THE PERIPHERY A MID/UPPER LEVEL RIDGE BUILDING ACROSS THE PLAINS. AT THE SAME TIME...A SHORTWAVE TROUGH WILL DROP ACROSS THE EASTERN GREAT LAKES. THIS SHORTWAVE WILL DEVELOP A BACK DOOR COLD FRONT WHICH WILL PUSH TOWARD THE OHIO VALLEY THIS EVENING. AHEAD OF THIS FRONT...AN INCREASINGLY UNSTABLE BOUNDARY LAYER WILL COMBINE WITH DEEP SHEAR TO DEVELOP THUNDERSTORMS ACROSS OUR AREA LATE THIS AFTERNOON AND INTO THE EVENING. SOME OF THESE STORMS HAVE THE POTENTIAL TO BECOME SEVERE. THE MAIN THREAT FROM THESE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS. HOWEVER...CANNOT RULE OUT AN ISOLATED TORNADO. OVERALL...CONVECTION WILL INITIATE ACROSS THE NORTH LATE THIS AFTERNOON...AND PUSH SSE ACROSS OUR SOUTH THIS EVENING WITH THE MEAN FLOW. HAVE FAVORED THE 12Z RUC FOR THIS UPDATE FOR TEMPS AND STORM TIMING. && .SHORT TERM /9 PM THIS EVENING THROUGH TUESDAY/... A BACK DOOR TYPE COLD FRONT TO DROP SOUTH THRU THE OHIO VALLEY AND STALL OUT OVER THE TN VLY OVERNIGHT. WL BUMP POPS UP TO LKLY EARLY ACRS THE SE WHERE BEST FORCING WL EXIST AND THEN TAPER PRECIP OFF FROM NORTH TO SOUTH. SOME OF THE STORMS MAY BE SEVERE DURING INTO THE EARLY EVENING HOURS WITH THE MAIN THREATS BEING WIND AND HAIL. SFC HIGH PRESSURE WILL BRIEFLY BUILD INTO THE FA MONDAY PROVIDING A TEMPORARY DRY PERIOD. HAVE TRENDED MONDAYS HIGHS A LTL COOLER ON MONDAY...FROM THE MID 60S NE TO THE MID/UPR 70S SOUTHWEST. THE MID LEVEL RIDGE WL BUILD E INTO THE REGION WITH UPPER LEVEL DISTURBANCE PASSING THRU THE GREAT LAKES TUESDAY. ASSOCIATED SFC WAVE TO TRACK THRU THE SRN GREAT LAKES. FRONT BOUNDARY TO PIVOT BACK NORTHEAST AS A WARM FRONT LATE MON NIGHT/TUE AND THEN COLD FRONT TO DROP BACK DOWN THRU THE OHIO VALLEY TUES NIGHT. NUMERICAL MODELS ARE NOT IN AGREEMENT REGARDING THIS SYSTEM AND HOW ACTIVE THE INITIAL WARM FRONT WL BE LATE MONDAY NIGHT/TUES. HAVE CHANCE/SLIGHT POPS RE-DEVELOPING LATE WITH THE BEST PROBABILITY ACRS W CENTRAL OHIO. THEN ALLOW CHC POPS TO LAY OUT E-W ON TUESDAY WITH THE APPROACH OF FRONT. CONFIDENCE IS NOT HIGH REGARDING PRECIP CHANCES TUESDAY. ETA/GFS SOLNS ARE FASTER BRINGING THE FRONT IN...WHICH THE ECMWF HOLDS IT BACK. GOING WITH A SLIGHTLY SLOWER SOLN HAVE WARM TEMPS WITH TUESDAYS FCST HIGHS RANGING FROM THE LOWER 70S FAR N TO AROUND 80 SOUTH. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HAVE FAVORED NON-GFS SOLUTION EARLY ON. THIS WOULD LEAD TO A SLOWER PROGRESSION OF A FRONT AND ASSOCIATED PRECIPITATION. HOWEVER THERE COULD BE SOME ELEVATED SHOWERS AND THUNDERSTORMS TUESDAY MORNING WELL AHEAD OF THE FRONT. BUT MOST STORMS SHOULD HOLD OFF UNTIL LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT AS THE FRONT MOVES THROUGH. THIS BOUNDARY WILL STALL IN THE TENNESSEE VALLEY AS HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES ON WEDNESDAY. A CLOSED LOW WILL PASS SOUTH OF THE REGION ON THURSDAY AND THURSDAY NIGHT WHICH MAY SPREAD SHOWERS AND THUNDERSTORMS BACK INTO THE SOUTHERN ZONES. AFTER THIS PASSES HIGH PRESSURE WILL BE ABLE TO BUILD SOUTH OVER THE REGION FOR THE END OF THE WEEK. ABOVE NORMAL TEMPERATURES AT THE BEGINNING OF THE PERIOD WILL TREND TOWARDS NORMAL BY LATER IN THE WEEK. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AFTER CLEARING DURING THE EARLY AFTERNOON...THUNDERSTORMS WILL DEVELOP OUT AHEAD OF A BACK DOOR COLD FRONT LATE THIS AFTERNOON. THESE STORMS WILL LIKELY AFFECT ALL TERMINALS DURING THE EVENING HOURS. EXACT TIMING IS STILL A BIT UNCERTAIN FOR THE ARRIVAL OF THESE STORMS...THEREFORE HAVE KEPT ANY TEMPOS OUT OF THE FORECAST FOR NOT. THESE WILL LIKELY BE ADDED IN AMENDMENTS LATER ON...AFTER THE STORMS ACTUALLY DEVELOP. REGARDLESS...MVFR/IFR VSBYS WILL BE POSSIBLE IN HEAVIER STORMS. WINDS WILL START OF SOUTHWESTERLY...THEN WILL VEER AS THE STORMS PUSH ACROSS THE AREA...AND THE COLD FRONT MOVES THROUGH OVERNIGHT. BY MONDAY MORNING...WINDS WILL BE NORTHEASTERLY AT 5 TO 10 KT. THERE MAY BE A BRIEF PERIOD AFTER FRONTAL PASSAGE OVERNIGHT TONIGHT WHERE CIGS DROP BELOW 3 KFT AS WELL. VFR CONDITIONS ARE EXPECTED DURING THE DAY MONDAY. OUTLOOK...SCATTERED THUNDERSTORMS POSSIBLE MONDAY NIGHT INTO TUESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...AR NEAR TERM...LATTO SHORT TERM...AR LONG TERM... AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS SPOKANE WA
225 PM PDT Sun Apr 1 2012 .SYNOPSIS... The widespread wet weather over the past several days will come to an end tonight leading to a dry start of the work week. A Pacific cold front will move through the area Tuesday night and Wednesday for more rain and mountain snow. The remainder of the week will see cool temperatures with afternoon and evening showers. Next weekend should be dry and warmer. && .DISCUSSION... Tonight: Afternoon instability convective showers will quickly die off this evening along with the winds. The HRRR model (which has done a great job with the convective line between Coulee Dam and Spokane) is suggesting the formation of a convective line that will move across the Spokane/Cd`A metro area around 7pm this evening. Not enough confidence to hit the forecast hard but the HRRR suggests it would be a graupel shower. Winds are gusting to 35 mph but should be diminishing quickly so will cancel the wind advisory with the afternoon forecast package. Another minor wave has moved onto the Oregon coast today. Models show the remnants of this wave tracking across northern Oregon and then into the southern Panhandle. Will keep pops in the Panhandle higher south of I-90. Any precip that does fall would all be in the form of snow as snow levels come crashing down to the valleys overnight. Light accumulations are possible in the valleys south/east of Pullman. RJ Monday through Tuesday night...High pressure will build over the region on Monday for a warming and drying trend. This will be followed by another deep low pressure system moving into the region Tuesday and Tuesday night. Monday and Monday night the ridge axis will be over the Inland Northwest Monday morning ans slide east through the day. The 12z models were showing a weak wave moving through my southeast zones overnight and early Monday morning, with the NAM being a bit stronger with this feature. The 18z NAM is still showing the wave, but not quite as robust. However with southwest flow and lingering low level moisture some showers were kept in the forecast. For the rest of Monday southerly winds will result in up-sloping flow into the northern mountains. Some light showers will be possible, but not widespread and only light accumulations are expected at best. Otherwise the southerly flow will increase temperatures across the region into the upper 40s to upper 50s. Winds will remain gusty through the day, but less then Sunday. Tuesday and Tuesday night the flow will back to almost southerly as the upper level low currently moving through the Gulf of Alaska moves off the west coast. Southerly flow with warm air advection will increase into the 50s and 60s, which are 5 to 8 degrees above normal. Moisture will increase along the Cascades through the day as the southerly flow taps into deep atmospheric river. PW`S are on the order of .50 to .60 which are 120-130 percent of normal. With the upper level flow parallel to the front it will take time for precipitation to cross the Cascade through the day on Tuesday with little eastward movement expected until later in the afternoon/evening when the following cold front moves through the region. Snow levels start out above 4000 feet across the northwest zones and over 5500 feet across the southeast Tuesday, then drop below 2500 feet behind the cold front Tuesday night. By this time, however, the heaviest precipitation should have moved east in the warm sector. As such precipitation will be mainly as rain with high elevation snow turning to snow with and behind the front. Accumulations will only be a few to several inches near the Cascade crest and less for the northern and eastern mountains. /Tobin Wednesday through Sunday: A longwave trough will settle into the region on Wednesday and remain stationary over the Interior West through much of the work-week courtesy of a blocking high, downstream across the central US/Canada. In comparison to Tuesday, temperatures will be on the downward trend with widely scattered showers possible for any location, just about every day, through Saturday; especially late afternoon coinciding with afternoon heating. Models are in pretty good agreement regarding the placement/timing of the mid-level trough but continue to struggle resolving each shortwave circulating within. We have maintained the highest PoPs across the Northeast Mountains of WA and N ID due to breezy southwest flow initially however as each of these shortwaves pivoting within the mean trough, become better resolved, we can anticipate that each shortwave will organize larger clusters of showers and moderate changes to PoPs are highly anticipated. The upper-level trough will eventually fill and become replaced by shortwave ridging as a second pacific wave or "kicker" approaches the coast over the weekend. The evolution of this wave still carries a lot of uncertainty but loose agreement indicates the potential for seasonal temperatures and dry conditions to return to close out the weekend into the start of the new week. /sb && .AVIATION... 18z TAFS: Afternoon showers will be most numerous in the Panhandle and extreme eastern WA. Gusty winds will develop at most TAF sites but should subside by late afternoon. Look for IFR cigs to develop overnight at KGEG/KSFF/KCOE but these should lift by mid-morning on Monday. RJ && .PRELIMINARY POINT TEMPS/POPS... Spokane 31 52 39 62 39 45 / 20 10 0 10 60 60 Coeur d`Alene 31 49 36 61 38 44 / 30 10 0 10 70 70 Pullman 31 52 37 63 35 42 / 20 0 0 0 70 60 Lewiston 34 59 42 67 39 48 / 10 0 0 0 60 60 Colville 31 50 37 63 37 50 / 20 20 10 20 70 60 Sandpoint 30 47 35 60 38 44 / 40 10 10 10 70 70 Kellogg 31 45 33 59 36 41 / 40 20 10 10 80 90 Moses Lake 33 57 43 62 39 56 / 10 10 10 20 60 20 Wenatchee 36 56 43 56 35 54 / 10 10 10 40 40 20 Omak 31 54 40 58 35 53 / 10 10 10 60 50 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$