Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/31/13


AREA FORECAST DISCUSSION
NWS TAUNTON MA
709 AM EDT FRI MAR 29 2013 .SYNOPSIS... MILD AND MAINLY DRY WEATHER IS EXPECTED THROUGH THE FIRST PART OF THE WEEKEND. A SERIES OF FRONTS WILL BRING SOME WET WEATHER SUNDAY NIGHT INTO MONDAY...WITH COLDER WEATHER EXPECTED INTO THE MID PART OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 7 AM UPDATE... ONLY MINOR TWEAKS NEEDED TO THE FORECAST THIS MORNING. UPDATED SKIES TOWARD LATEST RAP SOLUTION GIVEN IT IS HANDLING SOME MID CLOUDS OVER SRN NEW HAMPSHIRE AND CLOUDS UPSTREAM ASSOCIATED WITH A SHORTWAVE EXPECTED TO MOVE OVER THE AREA TODAY. STILL EXPECTING ANOTHER ROUND OF DIURNALLY DRIVEN SHOWERS PARTICULARLY CENTRAL AND EASTERN PORTIONS OF THE FORECAST AREA...SO HAVE ADJUSTED POPS SOMEWHAT AS WELL. OTHERWISE...ASIDE FROM BRINGING TEMPS AND DWPTS UP TO CURRENT TRENDS...OTHER PARAMETERS REMAIN ON TRACK. PREVIOUS DISCUSSION... A MIXTURE OF CLOUDS AND SUNSHINE THIS MORNING WILL PROBABLY GIVE WAY TO MORE IN THE WAY OF CLOUDINESS DURING THE AFTERNOON. THIS A RESULT OF A MID LEVEL SHORTWAVE APPROACHING FROM THE WEST AND 500 MB TEMPS DROPPING BELOW -30C. THIS SHOULD RESULT IN ENOUGH INSTABILITY FOR ISOLATED SHOWERS TO DEVELOP DURING THE AFTERNOON. HOWEVER...AREAL COVERAGE OF ANY ACTIVITY THAT DEVELOPS SHOULD BE LIMITED AND THE VAST MAJORITY OF THE DAY SHOULD BE DRY IN A GIVEN LOCATION. THEREFORE...JUST WILL INCLUDE LOW POPS IN THE FORECAST. AS FOR HIGH TEMPS...THE ATMOSPHERE SHOULD BE WELL MIXED WITH NORTHWEST SURFACE WINDS. SO DESPITE 850 MB TEMPS AROUND -3C...HIGH TEMPS SHOULD REACH WELL INTO THE 50S ACROSS MOST LOCATIONS. WEAK GRADIENT MAY ALLOW FOR SEA BREEZES TO DEVELOP ALONG THE VERY IMMEDIATE COAST...RESULTING LOCALLY COOLER TEMPS IN THIS REGION DURING THE AFTERNOON. && .SHORT TERM /SATURDAY/... TONIGHT... ISOLATED DIURNALLY DRIVEN SHOWERS SHOULD DISSIPATE DURING THE EVENING HOURS. HOWEVER...CONSIDERABLE CLOUDINESS MAY LINGER WELL INTO THE OVERNIGHT HOURS GIVEN COLD POOL ALOFT AND A FAIR AMOUNT OF MID LEVEL MOISTURE. THEREFORE...THINK GUIDANCE NUMBERS MAY BE A BIT TOO COOL AND LOW TEMPS WILL MAINLY BE IN THE UPPER 20S TO THE MIDDLE 30S IN MOST LOCALES. SATURDAY... A NICE START TO THE WEEKEND IS ON TAP FOR SOUTHERN NEW ENGLAND. THE UPPER TROUGH BEGINS TO MOVE EAST OF THE REGION ALLOWING FOR RISING HEIGHT FIELDS. THIS SHOULD YIELD MAINLY DRY WEATHER AND MORE SUNSHINE THAN TODAY. HIGHS AGAIN SHOULD BE IN THE LOWER TO MIDDLE 50S ACROSS MOST LOCALES. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... * WARMER TEMPERATURES EXPECTED THROUGH THE WEEKEND * SHOWERS EXPECTED AHEAD OF WARM FRONT SUN AND MON * COOLER WEATHER MOVES BACK IN TUES AND WED OVERVIEW AND MODEL PREFERENCES... 29/00Z MODEL GUIDANCE SUITE IS BEGINNING TO CONVERGE ON BROAD SCALE PATTERN THROUGH MUCH OF THE LONG TERM. MAINLY IN THAT THEY CONTINUE THE GREENLAND BLOCK THAT HAS BEEN IN PLACE FOR MUCH OF THE LAST MONTH OR SO. THEREFORE THE CUTOFF LOW PRES ASSOCIATED WITH THE EARLY WEEK OCCLUSION/COLD FRONTAL PASSAGE WILL STALL IN THE NEWFOUNDLAND LABRADOR REGION...DRAWING A FAIR AMOUNT OF COLD AIR INTO SRN NEW ENGLAND THROUGH NEXT WEEK. WILL CONTINUE TO ERR TOWARD A GFS/ECMWF BLEND AS A BASELINE. THE ONLY CAVEAT WILL BE A SECONDARY ARCTIC FROPA STALLING S OF THE REGION AND SECONDARY SHORTWAVE AND SFC LOW WHICH WILL PASS ALONG IT ON TUE. LATEST GFS IS MORE SUPPRESSED...LEANING CLOSER TO ITS ENSEMBLE MEAN...WHILE ECMWF HAS ALWAYS BEEN AB IT MORE SUPPRESSED. THERE IS STILL THE SLIGHT THREAT FOR SOME LIGHT PRECIP /WHAT WOULD LIKELY BE SNOW/ ALONG THE S COAST WITH THIS WAVE...SO WILL MAINTAIN AT LEAST SLIGHT CHANCE POPS /CLOSER TO THE ECWMF SOLUTION/ ON TUE. DETAILS... SAT NIGHT INTO SUN... UPPER LVL RIDGE AND SFC HIGH PRES CREST OVER THE REGION AND BEGINS TO SLIDE E. THIS ALLOWS FOR WARM ADVECTION UNDER RETURN FLOW INTO SUN. THEREFORE...WARM TEMPS /POSSIBLY APPROACHING 60/ ARE LIKELY DISPUTE INCREASING CLOUDS IN ADVANCE OF OCCLUDED FRONT. MUCH OF THE DAY REMAINS DRY ALTHOUGH AREAS NEAR AND W OF THE CT VALLEY MAY BEGIN TO SEE SOME RAIN BY LATE AFTERNOON AND EVENING. SUN NIGHT AND MON... MODELS STILL SHOWING DECENT OCCLUSION PUSHING THROUGH THE AREA AS LOW PRES PASSES WELL N OF THE ST LAWRENCE VALLEY. DECENT MOISTURE AND LIFT SUPPORT WIDESPREAD QPF VALUES AROUND A HALF INCH ALTHOUGH WITH PWAT VALUES CLOSER TO 0.75-1.0 INCHES...A FEW LOCALLY HIGHER AMOUNTS ARE POSSIBLE. GIVEN THE WARM START AND DECENT RIDGING THE PRECIP WILL LIKELY REMAIN MOSTLY RAIN...ALTHOUGH THERMAL PROFILES DO SUGGEST THAT HIGHER TERRAIN OF SRN MA AND NRN MA MAY CHANGE OVER BRIEFLY LATE SUN NIGHT...WITH LITTLE ACCUMULATION. STEERING FLOW SUGGESTS THIS FRONT IS A FAST MOVER AND PRECIP MAY LIKELY DONE EVERYWHERE SAVE FOR MAYBE EXTREME N AND E LOCATIONS NOT LONG AFTER 06Z. HOWEVER...AFTER A BRIEF LULL...A SECONDARY ARCTIC FRONT IS EXPECTED TO PUSH THROUGH DURING THE AFTERNOON...PRECIP FROM THIS TOO WILL LIKELY BE SHOWERY AND MOSTLY RAIN TO START BUT A BRIEF CHANGE-OVER TO SNOW CANNOT BE RULED OUT THANKS TO A VERY COLD AIRMASS BUILDING IN FROM THE W BEHIND THE FRONT ESPECIALLY TOWARD THE OVERNIGHT HOURS. EXPECTING THAT THE FRONT SHOULD BE OFFSHORE BY EARLY OVERNIGHT MON NIGHT. TUE.... THE KEY HERE IS A MIX OF HOW QUICKLY SFC RIDGING MOVES IN AND WHERE THE ARCTIC FRONT STALLS IN PROXIMITY TO SRN NEW ENGLAND. THE ECMWF AND SOME ECENS/GEFS MEMBERS CONTINUE TO KEEP THE BAROCLINIC ZONE FROM THE DELMARVA TO ABOUT THE BENCHMARK...WHILE THE GFS AND A FEW ENSEMBLE MEMBERS ARE FURTHER S. WHEN A SECONDARY WAVE MOVES THROUGH A WEAK LOW PRES IS EXPECTED TO MOVE ALONG THIS WAVE. THE CLOSER PASS /ECMWF/ WOULD SUGGEST SOME PRECIP /LIKELY MOSTLY SNOW...ALTHOUGH SOME RAIN COULD STILL MIX IN GIVEN THE EARLY APRIL SUN ANGLE/ ESPECIALLY S OF THE MA PIKE WHILE THE GFS IS DRY. WILL STILL AT LEAST HAVE POPS BECAUSE THE POTENTIAL IS THERE GIVEN THE UPSTREAM BLOCK...BUT WILL NEED TO MONITOR THE SHORTWAVE ONCE IT BECOMES BETTER SAMPLED. WED INTO FRI... UPPER LVL CUTOFF HOLDS NEAR LABRADOR-NEWFOUNDLAND ALLOWING FOR A DRAW OF SEASONABLY COLD AIR INTO THE REGION AS STRONG HIGH PRES BUILDS OVER FROM THE W. LIKELY SEE MOSTLY DRY CONDITIONS WITH TEMPERATURES GENERALLY BELOW NORMAL FOR EARLY APRIL. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW...HIGH CONFIDENCE THROUGH SATURDAY AFTERNOON. VFR CONDITIONS DOMINATE MUCH OF THE DAY WITH SOME EVEN WITH SOME LOWER STRATO-CU EXPECTED TO BUILD IN THROUGH THE DAY. CAN/T RULE OUT SOME ISOLATED MVFR CIGS/VSBYS ASSOCIATED WITH SOME DIURNALLY DRIVEN SHOWERS PARTICULARLY DURING THE AFTERNOON HOURS. KBOS TAF...HIGH CONFIDENCE IN VFR BUT LOWER CONFIDENCE IN WIND DIRECTION. MAIN CONCERN IS THE POTENTIAL FOR A WEAK SEABREEZE DEVELOPMENT DURING THE AFTERNOON. WILL CARRY IT IN THE TAF DUE TO POTENTIAL...BUT SHOULD WINDS NEVER QUITE DIMINISH BELOW 10 KT MAY BE VERY LOW POTENTIAL IN SEA BREEZE COMING ONSHORE. WILL NEED TO KEEP AN EYE ON WINDS THROUGH THE DAY. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SAT NIGHT INTO EARLY SUN AFTERNOON...HIGH CONFIDENCE. VFR. LIGHT AND VRB WINDS BECOME MORE SW INTO SUN. LATE DAY SUN INTO MON...MODERATE CONFIDENCE. VFR GIVES WAY TO MIX OF MVFR AND POTENTIALLY IFR IN RAIN. BULK OF RAIN OCCURS EVENING AND EARLY OVERNIGHT SUN NIGHT WITH A BREAK EARLY MON. POSSIBLE MVFR AGAIN WITH COLD FRONT DURING MON AFTERNOON. TUESDAY...MODERATE TO HIGH CONFIDENCE. MAINLY VFR. && .MARINE... HIGH CONFIDENCE THROUGH SATURDAY AFTERNOON. WEAK PRESSURE GRADIENT WILL KEEP WINDS/SEAS BELOW SCA THRESHOLDS THROUGH THAT TIME. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SAT NIGHT INTO EARLY SUN...HIGH CONFIDENCE. WINDS AND SEAS REMAIN BELOW SMALL CRAFT THRESHOLDS THROUGH THE PERIOD. SUN NIGHT THROUGH TUE...MODERATE CONFIDENCE. A SERIES OF FRONTS CROSS THE WATERS SUN NIGHT AND MON. THIS WILL ALLOW WINDS TO APPROACH 25 KT AT TIMES PARTICULARLY ON THE OUTER WATERS. SEAS ALSO GRADUALLY BUILD TO 5-8 FT ON OUTER WATERS WHICH WILL LIKELY LINGER INTO TUE. SMALL CRAFT ADVISORIES ARE LIKELY NEEDED THROUGH THE PERIOD. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANK/DOODY NEAR TERM...FRANK/DOODY SHORT TERM...FRANK LONG TERM...DOODY AVIATION...FRANK/DOODY MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
320 AM EDT FRI MAR 29 2013 .SYNOPSIS... 07Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A GENERALLY BENIGN UPPER LEVEL PATTERN ACROSS THE CONUS THIS MORNING. NORTHERN STREAM FLOW FORMS A BROAD LONGWAVE RIDGE OVER THE INTER-MOUNTAIN WEST AND CENTRAL PLAINS BEFORE SLIPPING BACK TO THE SOUTHEAST INTO A BROAD TROUGH NOW EXITING INTO THE WESTERN ATLANTIC. 29/00Z KTBW SOUNDING PROFILE CONTINUED TO SHOW A DRY COLUMN THROUGH THE EXTENT OF THE TROP WITH A PW VALUE OF ONLY AROUND 0.3". WITH LITTLE MOISTURE AND ESSENTIALLY NO SYNOPTIC SUPPORT FOR LIFT...SKIES ARE MOSTLY CLEAR OVER THE REGION THIS MORNING. AT THE SURFACE...HIGH PRESSURE IS RIDGING DOWN OVER THE PENINSULA FROM THE SOUTHERN/CENTRAL APPALACHIANS. ONCE AGAIN THE LIGHT GRADIENT...AND DRY ATMOSPHERE ARE ALLOWING TEMPERATURES TO BECOME QUITE COOL FOR LATE MARCH DUE TO THE GOOD RADIATIONAL COOLING SETUP. DUE TO CURRENTLY SLIGHTLY HIGHER DEWPOINTS COMPARED TO PREVIOUS NIGHTS...NOT ANTICIPATING LOW TEMPERATURES TO DROP DOWN AS LOW AS WAS SEEN THE PAST COUPLE NIGHTS. HOWEVER...A FEW NORMALLY COLDER LOCATIONS OVER THE INTERIOR NATURE COAST AND ALSO DOWN ACROSS DE SOTO...HARDEE... AND HIGHLANDS COUNTIES MAY BRIEFLY DIP INTO THE MIDDLE 30S TOWARD SUNRISE WITH A THREAT FOR SOME PATCHY FROST. && .SHORT TERM (TODAY THROUGH SUNDAY)... TODAY/TONIGHT...A PLEASANT AND QUIET DAY ON TAP IN TERMS OF SENSIBLE WEATHER. SURFACE HIGH PRESSURE WILL HOLD IN CONTROL OF THE REGION UNDER A DEEP LAYER WEST TO NORTHWEST FLOW REGIME. THE LIGHT GRADIENT WILL NOT BE IDEAL FOR MIXING...HOWEVER ABUNDANT SUNSHINE WOULD HELP TEMPERATURES RISE INTO THE LOW/MID 70S NORTH OF I-4 AND MID/UPPER 70S SOUTH. SHOULD SEE JUST ENOUGH TERRESTRIAL WARMING TO FORCE A FEEBLE SEA-BREEZE NEAR THE COAST THIS AFTERNOON...WHICH WILL HELP KEEP THINGS A BIT COOLER AT THE BEACHES. LOW TEMPERATURES TONIGHT WILL CONTINUE THE SLOW WARMING TREND...BUT STILL BE QUITE A BIT BELOW AVERAGE FOR MANY LOCATIONS. LOOKS AS THROUGH TEMPS WILL STAY WARM ENOUGH TO PREVENT ANY FROST CONCERNS...WITH THE COLDEST SPOTS ACROSS THE NATURE COAST AND INTERIOR CENTRAL COUNTIES DROPPING DOWN TO AROUND 40. ELSEWHERE WIDESPREAD MID/UPPER 40S LOOK COMMON AWAY FROM THE WARMER SUNCOAST BEACHES. SATURDAY/SATURDAY NIGHT...THE WARMING TREND CONTINUES! SURFACE HIGH PRESSURE WILL SLIP OFF THE SE CONUS COAST...BUT CONTINUE TO RIDGE BACK ACROSS THE CENTRAL FL PENINSULA. SLIGHTLY BETTER MIXING AND MODIFIED LOW LEVEL AIRMASS SHOULD ALLOW AFTERNOON TEMPS TO REACH WELL UP INTO THE 70S NORTH AND INTO THE LOWER 80S SOUTH AWAY FROM THE BEACHES. THE BETTER WARMING SHOULD CERTAINLY HELP TO FORCE SEA-BREEZE CIRCULATIONS SATURDAY AFTERNOON AND KEEP THE BEACHES COOLER. THE SEA-BREEZES WILL HAVE MORE POTENTIAL TO MOVE INLAND NORTH OF TAMPA BAY WHERE THE GRADIENT FLOW ON THE NORTH SIDE OF THE RIDGE AXIS WILL AID IN THE EASTWARD EXPANSION OF THE CIRCULATION. THE COOLEST SHELF WATERS ARE STILL FOUND OFF THE NATURE COAST...AND WITH THIS IN MIND...HAVE TEMPERATURES DROPPING BACK DOWN TOWARD THE UPPER 60S/LOW 70S NEAR THE COAST TO THE NORTH OF TAMPA BAY DURING THE SECOND HALF OF THE AFTERNOON. PLENTY OF SUNSHINE IS LIKELY TO START THE DAY...HOWEVER DURING THE MIDDLE TO LATER PORTION OF THE AFTERNOON WOULD EXPECT A SLOW INCREASE IN MID/HIGH LEVEL CLOUDS TO FILTER THE SUN IN RESPONSE TO THE APPROACH OF A WEAK IMPULSE. SATURDAY NIGHT LOOKS TO BE DRY AND SEASONABLY COOL. COLDEST SPOTS WILL ONLY DROP INTO THE UPPER 40S WITH MOST LOCATIONS STAYING ABOVE 50. THESE NUMBERS ARE CLOSE TO THE MOS CONSENSUS...HOWEVER COULD SEE LOW TEMPS BEING EVEN WARMER...ESPECIALLY ACROSS THE NATURE COAST. LATEST GFS/NAM CROSS SECTIONS BOTH SHOWING A BRIEF BY DECENT SWATH OF MID/HIGH LEVEL MOISTURE AND SYNOPTIC LIFT ASSOCIATED WITH THE PASSAGE OF THE PRE-MENTIONED IMPULSE. ALL THE DYNAMICS AND MOISTURE ARE PRETTY HIGH...SO NOT ANTICIPATING ANY PRECIP POTENTIAL. HOWEVER...IF SKIES DO END UP MOSTLY CLOUDY...THEN TEMPS SHOULD HAVE A MORE DIFFICULT TIME FALLING FOR THE MAJORITY OF THE NIGHT. SUNDAY...INITIAL IMPULSE QUICKLY PULLS EAST OF THE AREA DURING THE MORNING. LOOKING WELL TO OUR NORTH...AN AMPLIFYING UPPER TROUGH WILL HELP PUSH A WEAK COLD FRONT INTO THE SOUTHEASTERN CONUS DURING THE DAY. THIS FRONT LOOKS TO STALL NORTH OF I-10 AND NEVER GET DOWN THIS FAR DURING THE UPCOMING WEEKEND. NOT OUT OF THE QUESTION TO SEE A BRIEF SHOWER OR TWO ACROSS LEVY/CITRUS COUNTIES ON SUNDAY... HOWEVER THE BETTER LOW LEVEL FOCUS FOR LIFT ASSOCIATED WITH THE FRONT IS CURRENTLY PROGGED TO STAY NORTH OF OUR ZONES. OF NOTE...THE CONVECTIVE PARAMETRIZATION SCHEMES FROM THE GFS AND SOME SREF MEMBERS ARE KICKING OFF OVER THE PENINSULA (SOUTH OF I-4) DURING SUNDAY AFTERNOON. AGAIN...NOT OUT OF THE QUESTION TO SEE A BRIEF SHOWER...HOWEVER...SURFACE DEWPOINTS IN THE 50S ARGUE AGAINST ANY INSTABILITY THAT WOULD CURRENTLY WARRANT SHOWER MENTION IN THE FORECAST. WILL KEEP POPS AT SILENT 10%. TEMPERATURES WILL CONTINUE TO CLIMB ANOTHER COUPLE OF DEGREES FROM HIGHS ON SATURDAY. && .LONG TERM (SUNDAY NIGHT THROUGH NEXT THURSDAY)... HE PERIOD BEGINS WITH AN UPPER TROUGH JUST NORTH OF THE UPPER GREAT LAKES WITH NEARLY ZONAL FLOW ALOFT THE GULF REGION...A FRONTAL BOUNDARY STRETCHED ALONG THE GULF COAST/SE STATES...AND ATLANTIC HIGH PRESSURE RIDGING WEST ACROSS FL TO THE GULF. THROUGH ABOUT MID-WEEK THE UPPER TROUGH SAGS SOUTHWARD SOME AS IT TRACKS ALONG THE GREAT LAKES...WITH THE FRONTAL BOUNDARY SHIFTING INTO NORTHERN GULF WATERS AND THE NORTHERN HALF OF FL AS THE SURFACE RIDGE MOVES EAST AND SOUTH. BY MID-WEEK THE UPPER TROUGH LIFTS NORTHEAST AS A SHORT WAVE TROUGH MOVES FROM THE ROCKIES INTO THE SOUTHERN PLAINS THEN EAST TO THE CENTRAL GULF COAST. THIS FORMS A SURFACE TROUGH/LOW INITIALLY OVER THE WEST OR SOUTHWEST GULF THAT MOVES UP TO THE NORTH-CENTRAL OR NORTHEAST GULF BY THE END OF THE PERIOD...WITH THE BOUNDARY ACROSS THE STATE MOVING NORTH AS A WARM FRONT. A SLIGHT CHANCE OF SHOWERS WILL ONLY REACH THE NORTHERN CWA MON AND TUE BUT THEN SPREAD SOUTHWARD ACROSS THE REST OF THE CWA WED AND THU...INCREASING TO LOW END CHANCE. TEMPERATURES WILL RUN ABOVE NORMAL ALTHOUGH THEY WILL DECREASE SLIGHTLY AFTER MID-WEEK DUE TO AN INCREASE IN CLOUDS AND RAIN CHANCES. && .AVIATION... VFR FOR THE NEXT 24 HOURS. LIGHT VARIABLE WINDS OVERNIGHT INCREASE AND BECOME NE OR EAST IN THE MORNING THEN SHIFT TO NORTH OR NW IN THE AFTERNOON. && .MARINE... HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN GULF THROUGH THE UPCOMING WEEKEND. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW HEADLINE CRITERIA WITH WINDS BECOME VARIABLE NEAR THE COAST EACH AFTERNOON WITH THE DEVELOPMENT OF SEA-BREEZE CIRCULATIONS. A WEAK FRONT WILL SETTLE INTO THE NORTHERN GULF AROUND TUESDAY OF NEXT WEEK FOLLOWED BY WHAT LOOKS TO BE A PERIOD OF INCLEMENT WEATHER FOR THE MIDDLE AND END OF THE WEEK. && .FIRE WEATHER... HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION THE NEXT COUPLE OF DAYS PROVIDING DRY CONDITIONS. WIDESPREAD DURATIONS OF CRITICALLY LOW RELATIVE HUMIDITY ARE EXPECTED TODAY WITH MINIMUM VALUES DROPPING INTO THE LOWER 20S FOR MANY LOCATIONS. RED FLAG WARNINGS REMAIN IN EFFECT FOR PINELLAS...HIGHLANDS...POLK...SARASOTA...AND LEE COUNTIES WHERE FORECASTED ERC VALUES ARE AT OR GREATER THAN 37. ANOTHER DAY WITH WIDESPREAD CRITICALLY LOW RELATIVE HUMIDITY VALUES EXPECTED FOR SATURDAY...HOWEVER THE MINIMUM VALUES SHOULD BE IN THE MIDDLE AND UPPER 20S. A FIRE WEATHER WATCH HAS BEEN ISSUED FOR POLK...HIGHLANDS...SARASOTA...AND LEE COUNTIES. PINELLAS AS BEEN LEFT OUT OF THE WATCH AS CRITICAL DURATIONS OF LOW RELATIVE HUMIDITY ARE NOT CURRENTLY EXPECTED ALONG THE COAST. && .PRELIMINARY POINT TEMPS/POPS... TPA 73 53 75 60 / 0 0 0 10 FMY 79 54 81 59 / 0 0 0 10 GIF 76 48 80 55 / 0 0 0 10 SRQ 73 51 75 57 / 0 0 0 10 BKV 75 42 78 49 / 0 0 0 10 SPG 73 59 76 62 / 0 0 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR HIGHLANDS-LEE-PINELLAS-POLK-SARASOTA. FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR HIGHLANDS-LEE-POLK-SARASOTA. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1220 PM CDT FRI MAR 29 2013 .DISCUSSION... ISSUED 948 AM CDT FRI MAR 29 2013 HIGH PRESSURE AXIS CURRENTLY ANALYZED FROM WISCONSIN SOUTHEAST INTO THE CAROLINAS. EARLIER WARM AIR ADVECTION SHOWERS HAVE SHIFTED INTO THE OHIO VALLEY...ALTHOUGH SOME ALTOCUMULUS LINGERS IN THE FORECAST AREA AND HAVE EVEN HAD A FEW SPRINKLES OUT OF IT AROUND CHAMPAIGN. WHILE THE ALTOCUMULUS SHOULD DIMINISH WITH TIME...CU-RULE OFF THE RAP MODEL SHOWS SOME DIURNAL CUMULUS POTENTIAL FOR THIS AFTERNOON...WITH THE NET RESULT BEING PARTLY TO MOSTLY SUNNY SKIES. MORNING COOPERATIVE OBSERVATIONS SHOWING ONLY 1 TO 3 INCHES OF SNOW LINGERING FROM NEAR LINCOLN SOUTHWEST TO PITTSFIELD AND TRACE AMOUNTS EASTWARD...AND MUCH OF THIS SHOULD DISAPPEAR TODAY AS HIGHS REACH INTO THE 50S. HAVE SENT SOME UPDATED GRIDS TO ADJUST HOURLY TRENDS...BUT NO CHANGES NEEDED TO THE ZONE FORECASTS AT THIS TIME. GEELHART && .AVIATION... ISSUED 1220 PM CDT FRI MAR 29 2013 VFR CONDITIONS EXPECTED THE NEXT 24 HOURS. SOME SCATTERED TO BROKEN CLOUDS AROUND 5000 FEET ARE EXPECTED THROUGH THE AFTERNOON. WOULD NOT BE SURPRISED TO SEE THESE LINGER NEAR KSPI/KDEC FURTHER INTO THE EVENING. SATURDAY MORNING...WILL BEGIN TO SEE A GENERAL INCREASE IN CLOUDS FROM THE WEST...ALTHOUGH REMAINING VERY HIGH THROUGH THE MORNING. WINDS THROUGH THIS EVENING WILL GENERALLY REMAIN EASTERLY DUE TO AN AREA OF HIGH PRESSURE OVER THE MIDWEST...THEN TREND TOWARD THE SOUTHEAST AND INCREASE ON SATURDAY AHEAD OF A COLD FRONT APPROACHING FROM THE WEST. GEELHART && .PREV DISCUSSION... ISSUED 236 AM CDT FRI MAR 29 2013 SHORT TERM...TODAY THROUGH SATURDAY SURFACE RIDGE AXIS EXTENDING FROM THE UPPER MS VALLEY SOUTHEAST INTO THE OHIO VALLEY PROVIDED LIGHT WINDS OVERNIGHT. SCATTERED SHOWERS WERE AFFECTING SOUTHERN MO IN THE VICINITY OF A SFC WARM FRONT...WHILE ELEVATED WARM ADVECTION WAS PRODUCING SHOWERS INTO SOUTHERN IL. OBSERVATIONAL TRENDS SUGGEST THIS ACTIVITY WILL REMAIN SOUTH OF THE AREA THIS MORNING...BUT MAIN AFFECT FOR MOST AREAS WILL BE AREAS OF AC AND MOSTLY CLOUDY SKIES THIS MORNING. AS THE SYSTEM SINKS SOUTHEAST...A CLEARING TREND WORKS IN FROM THE NORTH THIS AFTERNOON. WILL ADD A FEW DEGREES TO YESTERDAYS HIGHS WITH MOST AREAS GETTING INTO THE LOW/MID 50S. A COLD FRONT MOVING ACROSS THE STATE SATURDAY AFTERNOON/NIGHT BRINGS SCATTERED SHOWERS WITH GENERALLY LIGHT QPF OF A QUARTER TO LESS THAN A HALF INCH. 00Z NAM HAD TRENDED MUCH QUICKER WITH THIS FEATURE BRINGING SHOWERS ALL THE WAY TO EASTERN IL BY SAT AFTERNOON. FEEL THIS IS A BIT FAST AND HAVE BASED FORECAST ON SREF/GFS BLEND WHICH BRINGS RAIN WEST OF THE IL RIVER BY MID TO LATE AFTERNOON...THEN SHIFTS EAST ACROSS THE REMAINDER OF THE CWA THROUGH EVENING. SOUTHERLY FLOW AHEAD OF THE FRONT WILL PRODUCE THE WARMEST DAY OF THE MONTH FOR MANY AREAS WITH HIGHS IN THE UPPER 50S. LONG TERM...SUNDAY THROUGH THURSDAY NOT MUCH OF A COOL PUSH BEHIND THE INITIAL FRONT AND READINGS EXPECTED TO GET BACK UP INTO THE 50S SUNDAY ALONG WITH A FAIR AMOUNT OF SUNSHINE. AN ARCTIC FRONT DIVING IN FROM THE NORTH SUNDAY NIGHT SENDS TEMPERATURES CRASHING BACK WELL BELOW NORMAL. FRONTOGENETIC FORCING ALONG/BEHIND THE BOUNDARY WILL WRING OUT WHAT MOISTURE REMAINS AFTER THE PREVIOUS FRONTAL PASSAGE. THERMAL PROFILES SUGGEST THE BULK OF THE PRECIP TO FALL AS SNOW AFTER A BRIEF RAIN/SNOW MIX AT ONSET SUNDAY NIGHT. NAM MOST AGGRESSIVE AT BRINGING ACCUMULATING SNOW...BUT GIVEN PROGRESSIVE NATURE OF FRONT AND WARM GROUND FEEL ANY ACCUMULATIONS WILL BE MINOR. SNOW SHOULD EXIT THE SOUTH/EAST MONDAY MORNING. BRISK NORTHERLY WINDS ON THE EASTERN FLANK OF STRONG LATE SEASON 1035 MB ARCTIC HIGH BUILDING INTO THE NORTHERN PLAINS...BRINGS STRONG COLD ADVECTION. 850 MB TEMPS DIP AS LOW AS -12C ACROSS CENTRAL IL MONDAY AFTERNOON THROUGH TUESDAY. THIS PRODUCES TEMPERATURES 20+ DEGREES BELOW NORMAL WHICH MAY NOT BE TOO FAR FROM RECORD TERRITORY. IN CONTRAST TO THE LAST ARCTIC AIR MASS...CYCLONIC FLOW IS DISPLACED MUCH FARTHER NORTHEAST THIS TIME AROUND AND SHOULD RESULT IN MORE SUNSHINE BY DAY AND CLEAR COLD NIGHTS. UNSEASONABLY COLD AND DRY WEATHER CONTINUES THROUGH MID WEEK AS THE MODIFIED ARCTIC RIDGE SETTLES OVERHEAD. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
949 AM CDT FRI MAR 29 2013 .DISCUSSION... ISSUED 948 AM CDT FRI MAR 29 2013 HIGH PRESSURE AXIS CURRENTLY ANALYZED FROM WISCONSIN SOUTHEAST INTO THE CAROLINAS. EARLIER WARM AIR ADVECTION SHOWERS HAVE SHIFTED INTO THE OHIO VALLEY...ALTHOUGH SOME ALTOCUMULUS LINGERS IN THE FORECAST AREA AND HAVE EVEN HAD A FEW SPRINKLES OUT OF IT AROUND CHAMPAIGN. WHILE THE ALTOCUMULUS SHOULD DIMINISH WITH TIME...CU-RULE OFF THE RAP MODEL SHOWS SOME DIURNAL CUMULUS POTENTIAL FOR THIS AFTERNOON...WITH THE NET RESULT BEING PARTLY TO MOSTLY SUNNY SKIES. MORNING COOPERATIVE OBSERVATIONS SHOWING ONLY 1 TO 3 INCHES OF SNOW LINGERING FROM NEAR LINCOLN SOUTHWEST TO PITTSFIELD AND TRACE AMOUNTS EASTWARD...AND MUCH OF THIS SHOULD DISAPPEAR TODAY AS HIGHS REACH INTO THE 50S. HAVE SENT SOME UPDATED GRIDS TO ADJUST HOURLY TRENDS...BUT NO CHANGES NEEDED TO THE ZONE FORECASTS AT THIS TIME. GEELHART && .AVIATION... ISSUED 615 AM CDT FRI MAR 29 2013 MAIN FORECAST CONCERN THIS PERIOD WILL BE COVERAGE OF LOW VFR CIGS...ESP ACRS OUR SOUTHERN TAF (KSPI...KDEC AND KCMI) SITES LATER THIS MORNING INTO THE AFTERNOON HOURS. NOT MANY CHANGES PLANNED TO CURRENT SET OF TAFS AS MOISTURE FROM A DISTURBANCE PASSING TO OUR SOUTH MAY KEEP THE LOWER VFR CIGS AROUND A BIT LONGER ACROSS THE SOUTH BEFORE THEY PUSH OFF TO THE EAST AND SOUTH BY LATE AFTN...LEAVING MAINLY VFR CONDITIONS FOR TNT. WILL HAVE TO WATCH FOR THE POSSIBILITY OF SOME PATCHY FOG DEVELOP LATE TONIGHT BUT AT THIS TIME IT APPEARS THAT PROBABILITY IS TOO LOW TO INCLUDE IN THIS SET OF TAFS. WINDS WILL NOT BE A FACTOR THRU TNT WITH SPEEDS OF LESS THAN 10 KTS...MOSTLY OUT OF AN EASTERLY DIRECTION. SMITH && .PREV DISCUSSION... ISSUED 236 AM CDT FRI MAR 29 2013 SHORT TERM...TODAY THROUGH SATURDAY SURFACE RIDGE AXIS EXTENDING FROM THE UPPER MS VALLEY SOUTHEAST INTO THE OHIO VALLEY PROVIDED LIGHT WINDS OVERNIGHT. SCATTERED SHOWERS WERE AFFECTING SOUTHERN MO IN THE VICINITY OF A SFC WARM FRONT...WHILE ELEVATED WARM ADVECTION WAS PRODUCING SHOWERS INTO SOUTHERN IL. OBSERVATIONAL TRENDS SUGGEST THIS ACTIVITY WILL REMAIN SOUTH OF THE AREA THIS MORNING...BUT MAIN AFFECT FOR MOST AREAS WILL BE AREAS OF AC AND MOSTLY CLOUDY SKIES THIS MORNING. AS THE SYSTEM SINKS SOUTHEAST...A CLEARING TREND WORKS IN FROM THE NORTH THIS AFTERNOON. WILL ADD A FEW DEGREES TO YESTERDAYS HIGHS WITH MOST AREAS GETTING INTO THE LOW/MID 50S. A COLD FRONT MOVING ACROSS THE STATE SATURDAY AFTERNOON/NIGHT BRINGS SCATTERED SHOWERS WITH GENERALLY LIGHT QPF OF A QUARTER TO LESS THAN A HALF INCH. 00Z NAM HAD TRENDED MUCH QUICKER WITH THIS FEATURE BRINGING SHOWERS ALL THE WAY TO EASTERN IL BY SAT AFTERNOON. FEEL THIS IS A BIT FAST AND HAVE BASED FORECAST ON SREF/GFS BLEND WHICH BRINGS RAIN WEST OF THE IL RIVER BY MID TO LATE AFTERNOON...THEN SHIFTS EAST ACROSS THE REMAINDER OF THE CWA THROUGH EVENING. SOUTHERLY FLOW AHEAD OF THE FRONT WILL PRODUCE THE WARMEST DAY OF THE MONTH FOR MANY AREAS WITH HIGHS IN THE UPPER 50S. LONG TERM...SUNDAY THROUGH THURSDAY NOT MUCH OF A COOL PUSH BEHIND THE INITIAL FRONT AND READINGS EXPECTED TO GET BACK UP INTO THE 50S SUNDAY ALONG WITH A FAIR AMOUNT OF SUNSHINE. AN ARCTIC FRONT DIVING IN FROM THE NORTH SUNDAY NIGHT SENDS TEMPERATURES CRASHING BACK WELL BELOW NORMAL. FRONTOGENETIC FORCING ALONG/BEHIND THE BOUNDARY WILL WRING OUT WHAT MOISTURE REMAINS AFTER THE PREVIOUS FRONTAL PASSAGE. THERMAL PROFILES SUGGEST THE BULK OF THE PRECIP TO FALL AS SNOW AFTER A BRIEF RAIN/SNOW MIX AT ONSET SUNDAY NIGHT. NAM MOST AGGRESSIVE AT BRINGING ACCUMULATING SNOW...BUT GIVEN PROGRESSIVE NATURE OF FRONT AND WARM GROUND FEEL ANY ACCUMULATIONS WILL BE MINOR. SNOW SHOULD EXIT THE SOUTH/EAST MONDAY MORNING. BRISK NORTHERLY WINDS ON THE EASTERN FLANK OF STRONG LATE SEASON 1035 MB ARCTIC HIGH BUILDING INTO THE NORTHERN PLAINS...BRINGS STRONG COLD ADVECTION. 850 MB TEMPS DIP AS LOW AS -12C ACROSS CENTRAL IL MONDAY AFTERNOON THROUGH TUESDAY. THIS PRODUCES TEMPERATURES 20+ DEGREES BELOW NORMAL WHICH MAY NOT BE TOO FAR FROM RECORD TERRITORY. IN CONTRAST TO THE LAST ARCTIC AIR MASS...CYCLONIC FLOW IS DISPLACED MUCH FARTHER NORTHEAST THIS TIME AROUND AND SHOULD RESULT IN MORE SUNSHINE BY DAY AND CLEAR COLD NIGHTS. UNSEASONABLY COLD AND DRY WEATHER CONTINUES THROUGH MID WEEK AS THE MODIFIED ARCTIC RIDGE SETTLES OVERHEAD. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1227 PM EDT FRI MAR 29 2013 .UPDATE... ISSUED AT 1227 PM EDT FRI MAR 29 2013 GRID UPDATE COMPLETED TO ADJUST FOR GENERALLY FASTER TRENDS IN TEMP CLIMB...MUCH LOWER DEWPTS ACROSS THE NORTH AND SKY COVER. SLOWLY DECREASING AREA OF MID CLOUDS THAT ORIGINATED OVER N ILLINOIS WAS SLOWLY DRIFTING SE IMPACTING MAINLY ALONG AND SOUTH OF US 30. WARMING CLOUD TOPS AND OVERALL APPEARANCE OF THE CLOUDS WOULD SUGGEST A CONTINUATION OF MIXING OUT SHOULD OCCUR OVER THE NEXT COUPLE OF HOURS...LEADING TO SUNNY TO MOSTLY SUNNY SKIES. TEMPS CLIMBED FAIRLY RAPIDLY THIS MORNING BUT HAVE SINCE SHOWED SIGNS OF SLOWING DOWN. IN AREAS WHERE THE SNOW PACK HAS BEEN GONE MUCH DRIER SFC DEWPTS WERE IN PLACE WITH READINGS IN THE UPR TEENS TO LOWER 20S VS UPR 20S TO AROUND 30 IN FAR S SECTIONS. DO EXPECT THESE HIGHER DEWPTS TO MIX SOMEWHAT THROUGH THE DAY AS THE CLOUD COVER LEAVES. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 523 AM EDT FRI MAR 29 2013 WEAK SHORT WAVE AND ASSOCIATED JET STREAK MOVING ACROSS THE GREAT LAKES THIS MORNING. COUPLED WITH WEAK MID LEVEL THETA E ADVECTION THESE FEATURES HAVE HELPED GENERATE AN AREA OF MID LEVEL CLOUDS THIS MORNING JUST TO OUR WEST. RAP13 SEEMS TO HAVE BEST HANDLE ON THIS MOISTURE WITH ITS 850-700MB LAYER RH. HRRR IS TRYING TO CATCH UP BUT STILL DOES NOT APPEAR TO HAVE THE SCOPE SEEN ON SATELLITE. SPECTRAL MODELS GENERALLY CLUELESS. SHORT WAVE WILL PASS THROUGH OUR AREA DURING EARLY TO MID MORNING HOURS. RAP13 MOVES HIGHER RH VALUES ACROSS WESTERN HALF OF OUR AREA THIS MORNING AND GRADUALLY SINKS THIS AREA SOUTH WHILE MIXING ALSO HELPS TO ERODE CLOUDS. HAVE INCREASED CLOUD COVER THIS MORNING SUBSTANTIALLY ACROSS WESTERN AREAS USING SATELLITE TRENDS AND RAP AS GUIDANCE. GRADUALLY DECREASED AMOUNT OF SKY COVER BY EARLY AFTERNOON SO SHOULD SEE A PARTLY TO MOSTLY CLOUDY MORNING TRANSITIONING TO MOSTLY SUNNY THIS AFTERNOON. EASTERN AREAS TO REMAIN FAR ENOUGH REMOVED PER TRAJECTORIES TO KEEP MOSTLY SUNNY THROUGH THE DAY. RESULT OF THIS MAY HELP KEEP TEMPS DOWN A FEW DEGREES WEST BUT EXPECT RAPID INCREASE ONCE CLOUDS DEPART. OTHERWISE TEMPS WILL BE A FEW DEGREES WARMER THAN THURSDAY OUTSIDE OF CLOUDS. WARMER TEMPS ON SATURDAY AHEAD OF NEXT SHORT WAVE WITH HIGHS NEARING 60. INCREASING HIGH CLOUDS IN AFTERNOON MAY SLOW WARMING BUT IF SKIES REMAIN CLEAR WOULD EXPECT SOME AREAS INTO 60S GIVEN MOS COOL BIAS YESTERDAY WITH FULL SUN. STRONG THETA E SURGE WITH MID LEVEL TROUGH APPROACHING SAT NIGHT SHOULD LEAD TO RAIN SHOWERS. MODELS CONTINUE TO TREND FASTER WITH NAM12 SHOWING PCPN DURING FIRST HALF OF NIGHT. USED COMPROMISE OF SOLUTIONS FOR TIMING BUT LOOKS LIKE ALL AREAS WILL RECEIVE A NICE RAINFALL OF ONE QUARTER TO ONE HALF INCH. ELEVATED THUNDER STILL NOT OUT OF QUESTION BUT REMAINS LOW PROB EVENT SO NO INCLUSION JUST YET. IF WE CAN GET SOME LIGHTNING WITH THIS RAIN RAPID GREEN UP WOULD BE EXPECTED IN WAKE OF RAIN. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 523 AM EDT FRI MAR 29 2013 SUNDAY THROUGH THURSDAY...A WEAK UPPER LEVEL TROF WILL BE MOVING ACROSS THE AREA SUNDAY...FOLLOWED BY A COLD FRONT SUNDAY NIGHT. THERMAL PROFILES SUNDAY ARE BORDERLINE BETWEEN RAIN AND A RAIN/SNOW MIX SUNDAY MORNING OVER NORTHERN AREAS...ESPECIALLY THE GFS. FOR NOW LEFT JUST RAIN IN THE FCST GIVEN SFC TEMPERATURES MAINLY IN THE 40S AND NAM 1000/850 MB THICKNESSES ALMOST EXCLUSIVELY ABOVE 1300 METERS. VERY CHILLY AIR WILL ONCE AGAIN SPREAD ACROSS THE AREA SUNDAY NIGHT AND MONDAY. DELTA T VALUES SUPPORT SOME LAKE EFFECT SNOW SHOWERS...HOWEVER...VERY LITTLE PRECONDITIONING IS EXPECTED. A 300 TO 310 FETCH WITH UPSTREAM DEW PTS IN THE SINGLE DIGITS MAY NOT ALLOW MUCH MORE THAN LAKE EFFECT CLOUDS. OTHERWISE...ATTEMPTED TO TREND TEMPERATURES DOWN MONDAY NIGHT THROUGH WEDNESDAY IN LINE WITH THE GFS MEX MOS. 850 MB TEMPS TUESDAY MORNING NEAR -14C TUESDAY WILL HELP KEEP HIGHS IN THE 30S...ESPECIALLY NEAR THE LAKE WITH LAKE ENHANCED CLOUDS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1227 PM EDT FRI MAR 29 2013 A VFR MID DECK OF CLOUDS HAS BEEN PROGRESSIVELY MIXING OUT...IMPACTING ONLY FT WAYNE AT THIS TIME. OVER THE NEXT COUPLE OF HOURS CLEAR SKIES SHOULD SETTLE IN WITH CONTINUATION OF LIGHT WINDS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...FISHER SHORT TERM...LASHLEY LONG TERM...SKIPPER AVIATION...FISHER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
623 AM EDT FRI MAR 29 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 523 AM EDT FRI MAR 29 2013 WEAK SHORT WAVE AND ASSOCIATED JET STREAK MOVING ACROSS THE GREAT LAKES THIS MORNING. COUPLED WITH WEAK MID LEVEL THETA E ADVECTION THESE FEATURES HAVE HELPED GENERATE AN AREA OF MID LEVEL CLOUDS THIS MORNING JUST TO OUR WEST. RAP13 SEEMS TO HAVE BEST HANDLE ON THIS MOISTURE WITH ITS 850-700MB LAYER RH. HRRR IS TRYING TO CATCH UP BUT STILL DOES NOT APPEAR TO HAVE THE SCOPE SEEN ON SATELLITE. SPECTRAL MODELS GENERALLY CLUELESS. SHORT WAVE WILL PASS THROUGH OUR AREA DURING EARLY TO MID MORNING HOURS. RAP13 MOVES HIGHER RH VALUES ACROSS WESTERN HALF OF OUR AREA THIS MORNING AND GRADUALLY SINKS THIS AREA SOUTH WHILE MIXING ALSO HELPS TO ERODE CLOUDS. HAVE INCREASED CLOUD COVER THIS MORNING SUBSTANTIALLY ACROSS WESTERN AREAS USING SATELLITE TRENDS AND RAP AS GUIDANCE. GRADUALLY DECREASED AMOUNT OF SKY COVER BY EARLY AFTERNOON SO SHOULD SEE A PARTLY TO MOSTLY CLOUDY MORNING TRANSITIONING TO MOSTLY SUNNY THIS AFTERNOON. EASTERN AREAS TO REMAIN FAR ENOUGH REMOVED PER TRAJECTORIES TO KEEP MOSTLY SUNNY THROUGH THE DAY. RESULT OF THIS MAY HELP KEEP TEMPS DOWN A FEW DEGREES WEST BUT EXPECT RAPID INCREASE ONCE CLOUDS DEPART. OTHERWISE TEMPS WILL BE A FEW DEGREES WARMER THAN THURSDAY OUTSIDE OF CLOUDS. WARMER TEMPS ON SATURDAY AHEAD OF NEXT SHORT WAVE WITH HIGHS NEARING 60. INCREASING HIGH CLOUDS IN AFTERNOON MAY SLOW WARMING BUT IF SKIES REMAIN CLEAR WOULD EXPECT SOME AREAS INTO 60S GIVEN MOS COOL BIAS YESTERDAY WITH FULL SUN. STRONG THETA E SURGE WITH MID LEVEL TROUGH APPROACHING SAT NIGHT SHOULD LEAD TO RAIN SHOWERS. MODELS CONTINUE TO TREND FASTER WITH NAM12 SHOWING PCPN DURING FIRST HALF OF NIGHT. USED COMPROMISE OF SOLUTIONS FOR TIMING BUT LOOKS LIKE ALL AREAS WILL RECEIVE A NICE RAINFALL OF ONE QUARTER TO ONE HALF INCH. ELEVATED THUNDER STILL NOT OUT OF QUESTION BUT REMAINS LOW PROB EVENT SO NO INCLUSION JUST YET. IF WE CAN GET SOME LIGHTNING WITH THIS RAIN RAPID GREEN UP WOULD BE EXPECTED IN WAKE OF RAIN. && .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 523 AM EDT FRI MAR 29 2013 SUNDAY THROUGH THURSDAY...A WEAK UPPER LEVEL TROF WILL BE MOVING ACROSS THE AREA SUNDAY...FOLLOWED BY A COLD FRONT SUNDAY NIGHT. THERMAL PROFILES SUNDAY ARE BORDERLINE BETWEEN RAIN AND A RAIN/SNOW MIX SUNDAY MORNING OVER NORTHERN AREAS...ESPECIALLY THE GFS. FOR NOW LEFT JUST RAIN IN THE FCST GIVEN SFC TEMPERATURES MAINLY IN THE 40S AND NAM 1000/850 MB THICKNESSES ALMOST EXCLUSIVELY ABOVE 1300 METERS. VERY CHILLY AIR WILL ONCE AGAIN SPREAD ACROSS THE AREA SUNDAY NIGHT AND MONDAY. DELTA T VALUES SUPPORT SOME LAKE EFFECT SNOW SHOWERS...HOWEVER...VERY LITTLE PRECONDITIONING IS EXPECTED. A 300 TO 310 FETCH WITH UPSTREAM DEW PTS IN THE SINGLE DIGITS MAY NOT ALLOW MUCH MORE THAN LAKE EFFECT CLOUDS. OTHERWISE...ATTEMPTED TO TREND TEMPERATURES DOWN MONDAY NIGHT THROUGH WEDNESDAY IN LINE WITH THE GFS MEX MOS. 850 MB TEMPS TUESDAY MORNING NEAR -14C TUESDAY WILL HELP KEEP HIGHS IN THE 30S...ESPECIALLY NEAR THE LAKE WITH LAKE ENHANCED CLOUDS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 622 AM EDT FRI MAR 29 2013 VFR CONDITIONS EXPECTED THROUGH THE PERIOD. SATELLITE SHOWS AREA OF MID LEVEL CLOUDS THINNING WITH TIME AS THEY MOVE EAST INTO DRIER AIR AND MID LEVEL JET MAX EXITS REGION. A FEW MORE HOURS OF OCCASIONAL BKN080 POSSIBLE THIS MORNING BEFORE BECOMING SCT. WINDS WILL REMAIN LIGHT THIS MORNING AND SHOULD STAY UNDER 10 KNOTS TODAY. CLEAR SKIES AND LIGHT WINDS AGAIN TONIGHT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...LASHLEY LONG TERM...SKIPPER AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
525 AM EDT FRI MAR 29 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 523 AM EDT FRI MAR 29 2013 WEAK SHORT WAVE AND ASSOCIATED JET STREAK MOVING ACROSS THE GREAT LAKES THIS MORNING. COUPLED WITH WEAK MID LEVEL THETA E ADVECTION THESE FEATURES HAVE HELPED GENERATE AN AREA OF MID LEVEL CLOUDS THIS MORNING JUST TO OUR WEST. RAP13 SEEMS TO HAVE BEST HANDLE ON THIS MOISTURE WITH ITS 850-700MB LAYER RH. HRRR IS TRYING TO CATCH UP BUT STILL DOES NOT APPEAR TO HAVE THE SCOPE SEEN ON SATELLITE. SPECTRAL MODELS GENERALLY CLUELESS. SHORT WAVE WILL PASS THROUGH OUR AREA DURING EARLY TO MID MORNING HOURS. RAP13 MOVES HIGHER RH VALUES ACROSS WESTERN HALF OF OUR AREA THIS MORNING AND GRADUALLY SINKS THIS AREA SOUTH WHILE MIXING ALSO HELPS TO ERODE CLOUDS. HAVE INCREASED CLOUD COVER THIS MORNING SUBSTANTIALLY ACROSS WESTERN AREAS USING SATELLITE TRENDS AND RAP AS GUIDANCE. GRADUALLY DECREASED AMOUNT OF SKY COVER BY EARLY AFTERNOON SO SHOULD SEE A PARTLY TO MOSTLY CLOUDY MORNING TRANSITIONING TO MOSTLY SUNNY THIS AFTERNOON. EASTERN AREAS TO REMAIN FAR ENOUGH REMOVED PER TRAJECTORIES TO KEEP MOSTLY SUNNY THROUGH THE DAY. RESULT OF THIS MAY HELP KEEP TEMPS DOWN A FEW DEGREES WEST BUT EXPECT RAPID INCREASE ONCE CLOUDS DEPART. OTHERWISE TEMPS WILL BE A FEW DEGREES WARMER THAN THURSDAY OUTSIDE OF CLOUDS. WARMER TEMPS ON SATURDAY AHEAD OF NEXT SHORT WAVE WITH HIGHS NEARING 60. INCREASING HIGH CLOUDS IN AFTERNOON MAY SLOW WARMING BUT IF SKIES REMAIN CLEAR WOULD EXPECT SOME AREAS INTO 60S GIVEN MOS COOL BIAS YESTERDAY WITH FULL SUN. STRONG THETA E SURGE WITH MID LEVEL TROUGH APPROACHING SAT NIGHT SHOULD LEAD TO RAIN SHOWERS. MODELS CONTINUE TO TREND FASTER WITH NAM12 SHOWING PCPN DURING FIRST HALF OF NIGHT. USED COMPROMISE OF SOLUTIONS FOR TIMING BUT LOOKS LIKE ALL AREAS WILL RECEIVE A NICE RAINFALL OF ONE QUARTER TO ONE HALF INCH. ELEVATED THUNDER STILL NOT OUT OF QUESTION BUT REMAINS LOW PROB EVENT SO NO INCLUSION JUST YET. IF WE CAN GET SOME LIGHTNING WITH THIS RAIN RAPID GREEN UP WOULD BE EXPECTED IN WAKE OF RAIN. && .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 523 AM EDT FRI MAR 29 2013 SUNDAY THROUGH THURSDAY...A WEAK UPPER LEVEL TROF WILL BE MOVING ACROSS THE AREA SUNDAY...FOLLOWED BY A COLD FRONT SUNDAY NIGHT. THERMAL PROFILES SUNDAY ARE BORDERLINE BETWEEN RAIN AND A RAIN/SNOW MIX SUNDAY MORNING OVER NORTHERN AREAS...ESPECIALLY THE GFS. FOR NOW LEFT JUST RAIN IN THE FCST GIVEN SFC TEMPERATURES MAINLY IN THE 40S AND NAM 1000/850 MB THICKNESSES ALMOST EXCLUSIVELY ABOVE 1300 METERS. VERY CHILLY AIR WILL ONCE AGAIN SPREAD ACROSS THE AREA SUNDAY NIGHT AND MONDAY. DELTA T VALUES SUPPORT SOME LAKE EFFECT SNOW SHOWERS...HOWEVER...VERY LITTLE PRECONDITIONING IS EXPECTED. A 300 TO 310 FETCH WITH UPSTREAM DEW PTS IN THE SINGLE DIGITS MAY NOT ALLOW MUCH MORE THAN LAKE EFFECT CLOUDS. OTHERWISE...ATTEMPTED TO TREND TEMPERATURES DOWN MONDAY NIGHT THROUGH WEDNESDAY IN LINE WITH THE GFS MEX MOS. 850 MB TEMPS TUESDAY MORNING NEAR -14C TUESDAY WILL HELP KEEP HIGHS IN THE 30S...ESPECIALLY NEAR THE LAKE WITH LAKE ENHANCED CLOUDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY) ISSUED AT 123 AM EDT FRI MAR 29 2013 VFR CONDITIONS EXPECTED AT TAF SITES BUT SATELLITE SHOWS A LARGE AREA OF MID LEVEL CLOUDS ACROSS IL ASSOCIATED WITH WEAK SHORT WAVE AND MID LEVEL MOISTURE ADVECTION. RUC13 AND HRRR TO SOME EXTENT ONLY MODELS PICKING UP ON THESE CLOUDS WITH RUC13 850-700MB RH FIELDS HANDLING IT THE BEST. THIS GUIDANCE AND SATELLITE LOOPS SUPPPORT A SOUTHEAST MOVEMENT AND EXPECT THESE CLOUDS INTO KSBN IN NEXT FEW HOURS AND KFWA TOWARD DAYBREAK. SOUNDINGS AND CROSS SECTIONS SUGGEST CLOUDS TO LINGER THROUGH MID TO LATE MORNING BEFORE MIXING AND MOVING SOUTH. OTHERWISE LIGHT AND VARIABLE WINDS GENERALLY UNDER 10 KNOTS THROUGH THE PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...LASHLEY LONG TERM...SKIPPER AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
141 AM EDT FRI MAR 29 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 327 PM EDT THU MAR 28 2013 NO SENSIBLE WEATHER CONCERNS THROUGH THE PERIOD WITH SFC RIDGE AXIS...CURRENTLY LOCATED FROM THE ARROWHEAD OF MN INTO CENTRAL TENNESSEE...SET TO DRIFT SLOWLY EAST. EVEN ON THE "COLD" SIDE OF THE RIDGE...TEMPS HAVE REBOUNDED NICELY WITH MOST LOCATIONS IN THE MID 40S. SNOW PACK STILL EXISTS IN THE FAR SOUTHERN COUNTIES...HAMPERING THE WARM UP SLIGHTLY. HOWEVER...INCREASING LATE MARCH SUN ANGLE HELPING OFFSET THE USUAL COLD CONTRIBUTION WITH MOST SITES NOW PUSHING 40 AND SNOW PACK DWINDLING EACH HOUR. GENERALLY CLEAR SKIES WILL PREVAIL WITH OVERNIGHT LOWS VERY SIMILAR TO LAST NIGHT IN THE MID TO UPPER 20S. TEMPS WILL REBOUND ONCE AGAIN ON FRIDAY...WITH SOUNDING INDICATE MIXING THROUGH TO AT LEAST 900 MB. AFTERNOON HIGHS WILL BE AT LEAST AS HIGH...IF NOT A FEW DEGREES WARMER FRI AFTERNOON WITH MOST LOCATIONS IN THE UPR 40S TO AROUND 50. && .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 327 PM EDT THU MAR 28 2013 UPR LOW OVER NW TERRITORIES THIS AFTN WILL STRENGTHEN AND DIG SE TO ONTARIO OVER THE WEEKEND AS JET STREAK OVER THE GULF OF ALASKA PROPAGATES EAST INTO BASE OF THE TROF. LEAD SHRTWV TO S-SE OF UPR LOW WILL MOVE ACROSS THE GRTLKS SAT NGT/SUNDAY. LOW LEVEL WAA AND LINGERING DRY AIRMASS SHOULD ALLOW FOR ABOVE NORMAL TEMPS AHEAD OF THIS SYSTEM SAT. NAM APPEARS TO BE SUFFERING FROM LOW LEVEL COOL BIAS LATELY THUS LEANED TOWARD WARMER GFS/MAV GUIDANCE FOR HIGHS SAT FCST IN THE M-U50S. STRONG/DEEP UVM... LOW LEVEL THETA-E ADVECTION... AND WK INSTABILITY EXPECTED TO ACCOMPANY SHRTWV/CDFNT SAT NGT AS IT MOVES INTO THE CWA... THUS TRENDED POPS/QPF UP FOR THIS PERIOD... SOME POTENTIAL FOR ELEVATED TSTMS REACHING AS FAR NORTH AS OUR CWA... BUT HELD OFF ADDING TO FCST ATTM. FRONTAL BOUNDARY MOVG THROUGH ERN PORTION OF THE CWA SUNDAY MORNING WILL LIKELY RESULT IN SHOWERS CONTG THERE... WITH JUST A CHC FARTHER WEST. SHOULD BE A LITTLE COOLER SUNDAY BUT MAIN BLAST OF COLD AIR EXPECTED TO MOVE INTO THE AREA SUNDAY NIGHT. ALONG WITH THE SECONDARY CDFNT... SERIES OF MID LEVEL SHRTWV`S ROTATING AROUND ONTARIO LOW WILL MOVE THROUGH THE GRTLKS SUNDAY NIGHT/MONDAY...PSBLY ACCOMPANIED BY RAIN/SNOW SHOWERS. STRONG CANADIAN SFC HIGH EXPECTED TO MOVE SE ACROSS THE PLAINS AND INTO GRTLKS/OH VALLEY TUE-WED RESULTING IN DRY PERIOD. UNSEASONABLY COLD CONDITIONS EXPECTED WITH HIGHS 35-40 MON-TUE. TEMPS SHOULD WARM INTO THE 40S WED AS AIRMASS MODIFIES AND BACK TO NEAR NORMAL BY THU AS WAA ON BACKSIDE OF THE RIDGE AND AHEAD OF A WK CDFNT OVERSPREADS THE CWA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 134 AM EDT FRI MAR 29 2013 VFR CONDITIONS EXPECTED AT TAF SITES BUT SATELLITE SHOWS A LARGE AREA OF MID LEVEL CLOUDS ACROSS IL ASSOCIATED WITH WEAK SHORT WAVE AND MID LEVEL MOISTURE ADVECTION. RUC13 AND HRRR TO SOME EXTENT ONLY MODELS PICKING UP ON THESE CLOUDS WITH RUC13 850-700MB RH FIELDS HANDLING IT THE BEST. THIS GUIDANCE AND SATELLITE LOOPS SUPPPORT A SOUTHEAST MOVEMENT AND EXPECT THESE CLOUDS INTO KSBN IN NEXT FEW HOURS AND KFWA TOWARD DAYBREAK. SOUNDINGS AND CROSS SECTIONS SUGGEST CLOUDS TO LINGER THROUGH MID TO LATE MORNING BEFORE MIXING AND MOVING SOUTH. OTHERWISE LIGHT AND VARIABLE WINDS GENERALLY UNDER 10 KNOTS THROUGH THE PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...FISHER LONG TERM...JT AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS JACKSON KY
133 PM EDT FRI MAR 29 2013 .UPDATE... ISSUED AT 1253 PM EDT FRI MAR 29 2013 HAVE UPDATED NDFD AND ZFP FOR LATEST OBSERVATIONAL TRENDS. RAIN HAS MEASURED AT MONTICELLO AND IT HAS STARTED RAINING AT SME. MAIN CHANGES WERE TO REDUCE THE NORTHERN EXTENT OF ANY RAIN CHANCES. HAVE ALSO LOWERED MAXIMUM TEMPERATURES IN THE SOUTH WHERE EXTENSIVE CLOUD COVER WILL PERSIST THIS AFTERNOON. UPDATE ISSUED AT 948 AM EDT FRI MAR 29 2013 MESONET DATA SHOWING MEASURABLE RAIN HAS OCCURRED OVER MOST OF WESTERN KY AND AS FAR SOUTHEAST AS CUMBERLAND COUNTY. RAIN ALSO FALLING AS FAR NORTH AS EVV INDIANA. RADAR SHOWS MOVEMENT OF RAIN TO THE ESE...SO EXPECT NUMEROUS SHOWERS TO AFFECT THE FAR SOUTHWEST AND FAR SOUTHERN PART OF THE FORECAST AREA. THIS IS SUPPORTED BY SREF PROBABILITIES AND LATEST DATA FROM THE HRRR AND NAM. AS SUCH HAVE UPDATED NDFD AND ZFP TO INCREASE RAIN PROBABILITIES IN THE FAR SOUTHWEST AND FAR SOUTH TODAY. UPDATE ISSUED AT 740 AM EDT FRI MAR 29 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. ONLY MADE SOME SLIGHT CHANGES TO TEMPERATURES...DEW POINTS CLOUDS AND WINDS IN THE FIRST TWO PERIODS. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 308 AM EDT FRI MAR 29 2013 A WEAK WEATHER SYSTEM WILL BRING SOME LIGHT RAIN TO THE SOUTHWESTERN HALF OF EASTERN KENTUCKY TODAY. THIS SYSTEM IS A WARM FRONT WHICH WILL TRY MOVING INTO THE AREA BUT THEN BE PUSHED BACK TO THE SOUTH TONIGHT. THIS WILL MAKE FOR A DRY SATURDAY BEFORE THE NEXT SYSTEM STARTS PUSHING ITS WAY INTO THE AREA ON SATURDAY NIGHT. THE JURY IS OUT ABOUT HOW MUCH RAIN THE WEAK SYSTEM TODAY WILL BE ABLE TO PRODUCE. IT MAY BE A LOT OF CLOUDS AND SOME SPRINKLES...AT BEST AND JUST A COUPLE OF HUNDREDTHS OF AN INCH OF RAIN AT THE WORST. AS YOU MOVE TO THE NORTHEAST FROM WAYNE COUNTY...THE CHANCE FOR MEASURABLE RAIN DECREASES. EXPECTING HIGHS IN THE MID 50S TODAY AND THEN NEAR 60 ON SATURDAY AS SOME WARMER AIR WORKS ITS WAY INTO THE AREA. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 412 AM EDT FRI MAR 29 2013 THE GFS AND ECMWF ARE IN GOOD AGREEMENT THROUGH THE PERIOD. FOR THE LOCAL AREA THEY SHOW A WARM AIR ADVECTION REGIME DEVELOPING IN ADVANCE OF A COLD FRONT SATURDAY NIGHT...WITH THE COLD FRONT THEN PASSING THROUGH ON SUNDAY. THERE APPEARS TO BE A DECENT AMOUNT OF MOISTURE WHICH MAKES ITS WAY IN FROM THE GULF BEFORE THE FRONT ARRIVES...AND LIKELY POPS FROM GFS MEXMOS SEEM REASONABLE. MARGINAL DEEP INSTABILITY IS ALSO INDICATED...AND IS WORTH A MENTION OF A SLIGHT CHANCE OF THUNDER. ANY LINGERING PRECIP IN THE SOUTH AND EAST ASSOCIATED WITH THE COLD FRONT SHOULD EXIT MONDAY EVENING. HOWEVER...THERE IS ADDITIONAL POTENTIAL FOR MORE PRECIP TOWARD THE END OF THE NIGHT...ALBEIT SMALL. THE NAM SHOWS A WAVE PASSING TO OUR SOUTH AND GRAZING OUR AREA...WHILE THE GFS AND ECMWF ARE FURTHER SOUTH WITH IT. WITH THE NAM BEING THE ONLY MODEL THAT EVEN GETS PRECIP TO THE EDGE OF OUR AREA...WILL NOT BRING ANY PRECIP INTO THE LOCAL AREA WITH THIS SYSTEM. HOWEVER...ALL THREE MODELS SHOW ANOTHER COLD FRONT MOVING IN FROM THE NW TOWARD MONDAY MORNING. WHILE THEY KEEP THE DEEP MOISTURE WITH THE FRONT NEAR OR NORTH OF THE OHIO RIVER...CONFIDENCE IN TIMING IS NOT GOOD ENOUGH TO PRECLUDE PRECIP HERE...AND HAVE ALLOWED FOR A SLIGHT CHANCE IN THE NORTH AT DAWN. WILL USE CHANCE POPS FOR RAIN ON MONDAY AS THE FRONT MOVES THROUGH. HAVE RESERVED THE HIGHEST POPS WITH THIS FRONT...STILL IN CHANCE CATEGORY...FOR MONDAY NIGHT AS A WAVE MOVES ALONG THE FRONT AFTER IT HAS PASSED. UP UNTIL MONDAY THE PRECIP FORM SHOULD BE LIQUID...BUT ENOUGH COLD AIR ARRIVES TO THREATEN SNOW BEFORE POPS DROP OFF LATE MONDAY NIGHT. LARGE...COLD...SPRAWLING SURFACE HIGH PRESSURE THEN HEADS IN FROM THE NW AND IS EXPECTED TO BRING DRY WEATHER INTO THURSDAY. LOW PRESSURE PASSING WELL TO OUR SOUTH THURSDAY AND THURSDAY NIGHT LOOKS AT THIS POINT LIKE IT WILL GRAZE THE SOUTHERN PART OF THE FORECAST AREA WITH RAIN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 133 PM EDT FRI MAR 29 2013 VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. A WEAK WEATHER DISTURBANCE WILL BRING LIGHT RAIN TO THE EXTREME SOUTHERN PART OF THE FORECAST AREA THIS AFTERNOON...WELL SOUTH OF JKL...AND MAINLY SOUTH OF SME AND LOZ AS WELL. WHERE THE RAIN OCCURS LOCAL MVFR TO IFR CONDITIONS ARE POSSIBLE...MAINLY WITH LOWER VISIBILITIES. OUTSIDE OF THE RAIN AREA VFR CONDITIONS WILL PREVAIL TODAY. DEWPOINTS HAVE INCREASED IN THE FAR SOUTH TODAY...AND IF CLOUDS BREAK TONIGHT SOME FOG IS POSSIBLE. HOWEVER...AT THIS POINT EXPECT EXTENSIVE CLOUDINESS IN THE SOUTHERN PART OF THE FORECAST AREA TO LIMIT FOG FORMATION TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...JJ LONG TERM...HAL AVIATION...SBH
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
109 PM EDT FRI MAR 29 2013 ...Updated Aviation Discussion... .Short Term (Now - Saturday)... Issued at 300 AM EDT Fri Mar 29 2013 An upper level shortwave and weak sfc boundary were located to our WSW early this morning producing showers and t-storms from eastern KS to western KY. The latest RAP model guidance seems to be handling this area of precip quite well, so have relied on it for short term POPs. Rain showers look likely across portions of south central KY this morning before moving south of the area into TN this afternoon. Think that better lapse rates out west are producing the t-storms with this wave and do not anticipate those better lapse rates to translate eastward so will not include thunder in this forecast. For high temperatures today, have gone with mid 50s over southern Indiana and north central KY which will see less cloud cover overall and no precip. Lower 50s can be expected for highs over south central KY where rain is anticipated. Tonight sfc high pressure will quickly work in from the north allowing for dry conditions and only partly cloudy skies across southern IN and northern KY. Went with a decent temp gradient due to cloud cover with low to mid 30s for lows over southern IN/northern KY to upper 30s and lower 40s over south central KY. The next push of moisture doesn`t look to arrive until late Sat afternoon or evening as a warm front pushes into south central KY. Therefore, limited POP chances to just the afternoon hours over south central KY for Sat. The rest of the area should be dry and warm up quite nicely. With only partly cloudy skies anticipated during the morning and early afternoon, went with high temps in the low to mid 60s. .Long Term (Saturday Night - Thursday)... Issued at 300 AM EDT Fri Mar 29 2013 Cold front number one will be fast approaching from the northwest Saturday night. Rain and a few embedded rumbles of thunder will overspread the forecast area Saturday night and through the morning hours Sunday. Rain chances will diminish from west to east late Sunday morning, with a dry period anticipated from roughly Sunday afternoon through Sunday night. A second cold front will quickly enter the forecast area from the north Monday and sag south through Monday night. Expect rain chances to increase through the day Monday and rain should exit the southern CWA by Tuesday morning. Temperatures will fall behind the front Monday night and soundings indicate the potential for some smaller ice crystal growth. It appears the loss of moisture/ice crystals within the dendritic growth layer will limit large snowflake generation. So, there could be some light snow mixed with the rain overnight as the system exits. Then, high pressure will build across the Ohio Valley, with the active storm track being pushed well to our south. The only question is whether a southern track system Thursday will be deep enough to increase moisture and rain potential across the Ohio and Tennessee Valleys as it tracks across the Gulf States. Rain probabilities are low for Thursday, with an overall slower trend noted in latest guidance. Will go with a dry forecast Tuesday through Thursday, with perhaps a slight rain chance across our south and southeast CWA just beyond the long-term period. The cold front that swings through the area early Sunday will not be followed by a cold air mass. Still expect temperatures in the 60s Sunday afternoon. However, the passage of the second front on Monday will bring a return to unseasonably cool conditions through Thursday. The good news is temperatures appear to moderate some through the work week. So, while highs in the 40s are expected Tuesday, highs Thursday appear to reach the middle 50s. && .Aviation (18Z TAF Issuance)... Issued at 109 PM EDT Fri Mar 29 2013 Ceilings are the main challenge with this forecast package. Mesoscale models are showing MVFR clouds forming to our west early this afternoon and spreading eastward by mid and late afternoon, particularly over southern Kentucky. Recent obs show that some low stratus has indeed formed across southeast Missouri and southern Illinois. In southern Kentucky, GLW has started reporting a ceiling at 032. Will go ahead and bring an MVFR ceiling into BWG, but will keep it on the high side of MVFR -- above 2000 feet. Will monitor to see if we need to go lower. The rain at BWG should cease around 19Z. The northern TAF sites should stay VFR. Winds at all three sites will remain light and variable. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Short Term.......AMS Long Term........MJP Aviation.........13
AREA FORECAST DISCUSSION
NWS JACKSON KY
1254 PM EDT FRI MAR 29 2013 .UPDATE... ISSUED AT 1253 PM EDT FRI MAR 29 2013 HAVE UPDATED NDFD AND ZFP FOR LATEST OBSERVATIONAL TRENDS. RAIN HAS MEASURED AT MONTICELLO AND IT HAS STARTED RAINING AT SME. MAIN CHANGES WERE TO REDUCE THE NORTHERN EXTENT OF ANY RAIN CHANCES. HAVE ALSO LOWERED MAXIMUM TEMPERATURES IN THE SOUTH WHERE EXTENSIVE CLOUD COVER WILL PERSIST THIS AFTERNOON. UPDATE ISSUED AT 948 AM EDT FRI MAR 29 2013 MESONET DATA SHOWING MEASURABLE RAIN HAS OCCURRED OVER MOST OF WESTERN KY AND AS FAR SOUTHEAST AS CUMBERLAND COUNTY. RAIN ALSO FALLING AS FAR NORTH AS EVV INDIANA. RADAR SHOWS MOVEMENT OF RAIN TO THE ESE...SO EXPECT NUMEROUS SHOWERS TO AFFECT THE FAR SOUTHWEST AND FAR SOUTHERN PART OF THE FORECAST AREA. THIS IS SUPPORTED BY SREF PROBABILITIES AND LATEST DATA FROM THE HRRR AND NAM. AS SUCH HAVE UPDATED NDFD AND ZFP TO INCREASE RAIN PROBABILITIES IN THE FAR SOUTHWEST AND FAR SOUTH TODAY. UPDATE ISSUED AT 740 AM EDT FRI MAR 29 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. ONLY MADE SOME SLIGHT CHANGES TO TEMPERATURES...DEW POINTS CLOUDS AND WINDS IN THE FIRST TWO PERIODS. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 308 AM EDT FRI MAR 29 2013 A WEAK WEATHER SYSTEM WILL BRING SOME LIGHT RAIN TO THE SOUTHWESTERN HALF OF EASTERN KENTUCKY TODAY. THIS SYSTEM IS A WARM FRONT WHICH WILL TRY MOVING INTO THE AREA BUT THEN BE PUSHED BACK TO THE SOUTH TONIGHT. THIS WILL MAKE FOR A DRY SATURDAY BEFORE THE NEXT SYSTEM STARTS PUSHING ITS WAY INTO THE AREA ON SATURDAY NIGHT. THE JURY IS OUT ABOUT HOW MUCH RAIN THE WEAK SYSTEM TODAY WILL BE ABLE TO PRODUCE. IT MAY BE A LOT OF CLOUDS AND SOME SPRINKLES...AT BEST AND JUST A COUPLE OF HUNDREDTHS OF AN INCH OF RAIN AT THE WORST. AS YOU MOVE TO THE NORTHEAST FROM WAYNE COUNTY...THE CHANCE FOR MEASURABLE RAIN DECREASES. EXPECTING HIGHS IN THE MID 50S TODAY AND THEN NEAR 60 ON SATURDAY AS SOME WARMER AIR WORKS ITS WAY INTO THE AREA. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 412 AM EDT FRI MAR 29 2013 THE GFS AND ECMWF ARE IN GOOD AGREEMENT THROUGH THE PERIOD. FOR THE LOCAL AREA THEY SHOW A WARM AIR ADVECTION REGIME DEVELOPING IN ADVANCE OF A COLD FRONT SATURDAY NIGHT...WITH THE COLD FRONT THEN PASSING THROUGH ON SUNDAY. THERE APPEARS TO BE A DECENT AMOUNT OF MOISTURE WHICH MAKES ITS WAY IN FROM THE GULF BEFORE THE FRONT ARRIVES...AND LIKELY POPS FROM GFS MEXMOS SEEM REASONABLE. MARGINAL DEEP INSTABILITY IS ALSO INDICATED...AND IS WORTH A MENTION OF A SLIGHT CHANCE OF THUNDER. ANY LINGERING PRECIP IN THE SOUTH AND EAST ASSOCIATED WITH THE COLD FRONT SHOULD EXIT MONDAY EVENING. HOWEVER...THERE IS ADDITIONAL POTENTIAL FOR MORE PRECIP TOWARD THE END OF THE NIGHT...ALBEIT SMALL. THE NAM SHOWS A WAVE PASSING TO OUR SOUTH AND GRAZING OUR AREA...WHILE THE GFS AND ECMWF ARE FURTHER SOUTH WITH IT. WITH THE NAM BEING THE ONLY MODEL THAT EVEN GETS PRECIP TO THE EDGE OF OUR AREA...WILL NOT BRING ANY PRECIP INTO THE LOCAL AREA WITH THIS SYSTEM. HOWEVER...ALL THREE MODELS SHOW ANOTHER COLD FRONT MOVING IN FROM THE NW TOWARD MONDAY MORNING. WHILE THEY KEEP THE DEEP MOISTURE WITH THE FRONT NEAR OR NORTH OF THE OHIO RIVER...CONFIDENCE IN TIMING IS NOT GOOD ENOUGH TO PRECLUDE PRECIP HERE...AND HAVE ALLOWED FOR A SLIGHT CHANCE IN THE NORTH AT DAWN. WILL USE CHANCE POPS FOR RAIN ON MONDAY AS THE FRONT MOVES THROUGH. HAVE RESERVED THE HIGHEST POPS WITH THIS FRONT...STILL IN CHANCE CATEGORY...FOR MONDAY NIGHT AS A WAVE MOVES ALONG THE FRONT AFTER IT HAS PASSED. UP UNTIL MONDAY THE PRECIP FORM SHOULD BE LIQUID...BUT ENOUGH COLD AIR ARRIVES TO THREATEN SNOW BEFORE POPS DROP OFF LATE MONDAY NIGHT. LARGE...COLD...SPRAWLING SURFACE HIGH PRESSURE THEN HEADS IN FROM THE NW AND IS EXPECTED TO BRING DRY WEATHER INTO THURSDAY. LOW PRESSURE PASSING WELL TO OUR SOUTH THURSDAY AND THURSDAY NIGHT LOOKS AT THIS POINT LIKE IT WILL GRAZE THE SOUTHERN PART OF THE FORECAST AREA WITH RAIN. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 740 AM EDT FRI MAR 29 2013 VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. HIGH CLOUDS AND MIDDLE CLOUDS HAVE ARRIVED AND WILL BE LOWERING THROUGH THE DAY TODAY. ISOLATED LIGHT SHOWER POSSIBLE BY MID DAY IN THE CUMBERLAND VALLEY. MAINTAINED A VCSH AND CIGS AROUND 5K FEET FOR THIS IN THE LOZ AND SME TAFS. WINDS WILL HAVE A W TO WNW TENDENCY...AT 5 KTS OR LESS THROUGH THE PERIOD AS WELL. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...JJ LONG TERM...HAL AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
948 AM EDT FRI MAR 29 2013 .UPDATE... ISSUED AT 948 AM EDT FRI MAR 29 2013 MESONET DATA SHOWING MEASURABLE RAIN HAS OCCURRED OVER MOST OF WESTERN KY AND AS FAR SOUTHEAST AS CUMBERLAND COUNTY. RAIN ALSO FALLING AS FAR NORTH AS EVV INDIANA. RADAR SHOWS MOVEMENT OF RAIN TO THE ESE...SO EXPECT NUMEROUS SHOWERS TO AFFECT THE FAR SOUTHWEST AND FAR SOUTHERN PART OF THE FORECAST AREA. THIS IS SUPPORTED BY SREF PROBABILITIES AND LATEST DATA FROM THE HRRR AND NAM. AS SUCH HAVE UPDATED NDFD AND ZFP TO INCREASE RAIN PROBABILITIES IN THE FAR SOUTHWEST AND FAR SOUTH TODAY. UPDATE ISSUED AT 740 AM EDT FRI MAR 29 2013 UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL TRENDS. ONLY MADE SOME SLIGHT CHANGES TO TEMPERATURES...DEW POINTS CLOUDS AND WINDS IN THE FIRST TWO PERIODS. THE REST OF THE FORECAST IS ON TRACK. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 308 AM EDT FRI MAR 29 2013 A WEAK WEATHER SYSTEM WILL BRING SOME LIGHT RAIN TO THE SOUTHWESTERN HALF OF EASTERN KENTUCKY TODAY. THIS SYSTEM IS A WARM FRONT WHICH WILL TRY MOVING INTO THE AREA BUT THEN BE PUSHED BACK TO THE SOUTH TONIGHT. THIS WILL MAKE FOR A DRY SATURDAY BEFORE THE NEXT SYSTEM STARTS PUSHING ITS WAY INTO THE AREA ON SATURDAY NIGHT. THE JURY IS OUT ABOUT HOW MUCH RAIN THE WEAK SYSTEM TODAY WILL BE ABLE TO PRODUCE. IT MAY BE A LOT OF CLOUDS AND SOME SPRINKLES...AT BEST AND JUST A COUPLE OF HUNDREDTHS OF AN INCH OF RAIN AT THE WORST. AS YOU MOVE TO THE NORTHEAST FROM WAYNE COUNTY...THE CHANCE FOR MEASURABLE RAIN DECREASES. EXPECTING HIGHS IN THE MID 50S TODAY AND THEN NEAR 60 ON SATURDAY AS SOME WARMER AIR WORKS ITS WAY INTO THE AREA. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 412 AM EDT FRI MAR 29 2013 THE GFS AND ECMWF ARE IN GOOD AGREEMENT THROUGH THE PERIOD. FOR THE LOCAL AREA THEY SHOW A WARM AIR ADVECTION REGIME DEVELOPING IN ADVANCE OF A COLD FRONT SATURDAY NIGHT...WITH THE COLD FRONT THEN PASSING THROUGH ON SUNDAY. THERE APPEARS TO BE A DECENT AMOUNT OF MOISTURE WHICH MAKES ITS WAY IN FROM THE GULF BEFORE THE FRONT ARRIVES...AND LIKELY POPS FROM GFS MEXMOS SEEM REASONABLE. MARGINAL DEEP INSTABILITY IS ALSO INDICATED...AND IS WORTH A MENTION OF A SLIGHT CHANCE OF THUNDER. ANY LINGERING PRECIP IN THE SOUTH AND EAST ASSOCIATED WITH THE COLD FRONT SHOULD EXIT MONDAY EVENING. HOWEVER...THERE IS ADDITIONAL POTENTIAL FOR MORE PRECIP TOWARD THE END OF THE NIGHT...ALBEIT SMALL. THE NAM SHOWS A WAVE PASSING TO OUR SOUTH AND GRAZING OUR AREA...WHILE THE GFS AND ECMWF ARE FURTHER SOUTH WITH IT. WITH THE NAM BEING THE ONLY MODEL THAT EVEN GETS PRECIP TO THE EDGE OF OUR AREA...WILL NOT BRING ANY PRECIP INTO THE LOCAL AREA WITH THIS SYSTEM. HOWEVER...ALL THREE MODELS SHOW ANOTHER COLD FRONT MOVING IN FROM THE NW TOWARD MONDAY MORNING. WHILE THEY KEEP THE DEEP MOISTURE WITH THE FRONT NEAR OR NORTH OF THE OHIO RIVER...CONFIDENCE IN TIMING IS NOT GOOD ENOUGH TO PRECLUDE PRECIP HERE...AND HAVE ALLOWED FOR A SLIGHT CHANCE IN THE NORTH AT DAWN. WILL USE CHANCE POPS FOR RAIN ON MONDAY AS THE FRONT MOVES THROUGH. HAVE RESERVED THE HIGHEST POPS WITH THIS FRONT...STILL IN CHANCE CATEGORY...FOR MONDAY NIGHT AS A WAVE MOVES ALONG THE FRONT AFTER IT HAS PASSED. UP UNTIL MONDAY THE PRECIP FORM SHOULD BE LIQUID...BUT ENOUGH COLD AIR ARRIVES TO THREATEN SNOW BEFORE POPS DROP OFF LATE MONDAY NIGHT. LARGE...COLD...SPRAWLING SURFACE HIGH PRESSURE THEN HEADS IN FROM THE NW AND IS EXPECTED TO BRING DRY WEATHER INTO THURSDAY. LOW PRESSURE PASSING WELL TO OUR SOUTH THURSDAY AND THURSDAY NIGHT LOOKS AT THIS POINT LIKE IT WILL GRAZE THE SOUTHERN PART OF THE FORECAST AREA WITH RAIN. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 740 AM EDT FRI MAR 29 2013 VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. HIGH CLOUDS AND MIDDLE CLOUDS HAVE ARRIVED AND WILL BE LOWERING THROUGH THE DAY TODAY. ISOLATED LIGHT SHOWER POSSIBLE BY MID DAY IN THE CUMBERLAND VALLEY. MAINTAINED A VCSH AND CIGS AROUND 5K FEET FOR THIS IN THE LOZ AND SME TAFS. WINDS WILL HAVE A W TO WNW TENDENCY...AT 5 KTS OR LESS THROUGH THE PERIOD AS WELL. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...JJ LONG TERM...HAL AVIATION...JJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
926 AM EDT FRI MAR 29 2013 .Forecast Update... Issued at 926 AM EDT Fri Mar 29 2013 Quick update to raise PoPs to 100% where it is currently raining and sky cover to 100% where it is currently overcast. Also bumped up precipitation amounts a bit based on totals coming in from western Kentucky this morning. && .Short Term (Now - Saturday)... Issued at 300 AM EDT Fri Mar 29 2013 An upper level shortwave and weak sfc boundary were located to our WSW early this morning producing showers and t-storms from eastern KS to western KY. The latest RAP model guidance seems to be handling this area of precip quite well, so have relied on it for short term POPs. Rain showers look likely across portions of south central KY this morning before moving south of the area into TN this afternoon. Think that better lapse rates out west are producing the t-storms with this wave and do not anticipate those better lapse rates to translate eastward so will not include thunder in this forecast. For high temperatures today, have gone with mid 50s over southern Indiana and north central KY which will see less cloud cover overall and no precip. Lower 50s can be expected for highs over south central KY where rain is anticipated. Tonight sfc high pressure will quickly work in from the north allowing for dry conditions and only partly cloudy skies across southern IN and northern KY. Went with a decent temp gradient due to cloud cover with low to mid 30s for lows over southern IN/northern KY to upper 30s and lower 40s over south central KY. The next push of moisture doesn`t look to arrive until late Sat afternoon or evening as a warm front pushes into south central KY. Therefore, limited POP chances to just the afternoon hours over south central KY for Sat. The rest of the area should be dry and warm up quite nicely. With only partly cloudy skies anticipated during the morning and early afternoon, went with high temps in the low to mid 60s. .Long Term (Saturday Night - Thursday)... Issued at 300 AM EDT Fri Mar 29 2013 Cold front number one will be fast approaching from the northwest Saturday night. Rain and a few embedded rumbles of thunder will overspread the forecast area Saturday night and through the morning hours Sunday. Rain chances will diminish from west to east late Sunday morning, with a dry period anticipated from roughly Sunday afternoon through Sunday night. A second cold front will quickly enter the forecast area from the north Monday and sag south through Monday night. Expect rain chances to increase through the day Monday and rain should exit the southern CWA by Tuesday morning. Temperatures will fall behind the front Monday night and soundings indicate the potential for some smaller ice crystal growth. It appears the loss of moisture/ice crystals within the dendritic growth layer will limit large snowflake generation. So, there could be some light snow mixed with the rain overnight as the system exits. Then, high pressure will build across the Ohio Valley, with the active storm track being pushed well to our south. The only question is whether a southern track system Thursday will be deep enough to increase moisture and rain potential across the Ohio and Tennessee Valleys as it tracks across the Gulf States. Rain probabilities are low for Thursday, with an overall slower trend noted in latest guidance. Will go with a dry forecast Tuesday through Thursday, with perhaps a slight rain chance across our south and southeast CWA just beyond the long-term period. The cold front that swings through the area early Sunday will not be followed by a cold air mass. Still expect temperatures in the 60s Sunday afternoon. However, the passage of the second front on Monday will bring a return to unseasonably cool conditions through Thursday. The good news is temperatures appear to moderate some through the work week. So, while highs in the 40s are expected Tuesday, highs Thursday appear to reach the middle 50s. && .Aviation (12Z TAF Issuance)... Issued at 645 AM EDT Fri Mar 29 2013 VFR conditions are expected for this TAF period. Mid and upper level clouds will continue to stream into the area this morning and continue through the day as an upper level shortwave passes through south central KY. This wave looks to bring precip in the form of rain showers to BWG today. These showers have made it into the BWG terminal with the main push of moisture progged to occur from roughly 13Z-20Z. SDF/LEX still look to remain dry although will need to monitor the northern extent of the precip shield to make sure it doesn`t creep into SDF. The 0Z NAM indicates MVFR conditions will develop at BWG today, but feel it is an outlier at this point compared to other model runs and upstream obs. Still will need to watch BWG for some cig/vsby restrictions today. Winds will be hard to pin down throughout the TAF period. Generally they will remain light (under 5 kts). Variable winds can be expected during the early morning hours and again tonight. Think that the predominant wind direction at BWG this afternoon will be SSE with SDF/LEX winds predominantly SSW. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........13 Short Term.......AMS Long Term........MJP Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
648 AM EDT FRI MAR 29 2013 ...Updated Aviation Discussion... .Short Term (Now - Saturday)... Issued at 300 AM EDT Fri Mar 29 2013 An upper level shortwave and weak sfc boundary were located to our WSW early this morning producing showers and t-storms from eastern KS to western KY. The latest RAP model guidance seems to be handling this area of precip quite well, so have relied on it for short term POPs. Rain showers look likely across portions of south central KY this morning before moving south of the area into TN this afternoon. Think that better lapse rates out west are producing the t-storms with this wave and do not anticipate those better lapse rates to translate eastward so will not include thunder in this forecast. For high temperatures today, have gone with mid 50s over southern Indiana and north central KY which will see less cloud cover overall and no precip. Lower 50s can be expected for highs over south central KY where rain is anticipated. Tonight sfc high pressure will quickly work in from the north allowing for dry conditions and only partly cloudy skies across southern IN and northern KY. Went with a decent temp gradient due to cloud cover with low to mid 30s for lows over southern IN/northern KY to upper 30s and lower 40s over south central KY. The next push of moisture doesn`t look to arrive until late Sat afternoon or evening as a warm front pushes into south central KY. Therefore, limited POP chances to just the afternoon hours over south central KY for Sat. The rest of the area should be dry and warm up quite nicely. With only partly cloudy skies anticipated during the morning and early afternoon, went with high temps in the low to mid 60s. .Long Term (Saturday Night - Thursday)... Issued at 300 AM EDT Fri Mar 29 2013 Cold front number one will be fast approaching from the northwest Saturday night. Rain and a few embedded rumbles of thunder will overspread the forecast area Saturday night and through the morning hours Sunday. Rain chances will diminish from west to east late Sunday morning, with a dry period anticipated from roughly Sunday afternoon through Sunday night. A second cold front will quickly enter the forecast area from the north Monday and sag south through Monday night. Expect rain chances to increase through the day Monday and rain should exit the southern CWA by Tuesday morning. Temperatures will fall behind the front Monday night and soundings indicate the potential for some smaller ice crystal growth. It appears the loss of moisture/ice crystals within the dendritic growth layer will limit large snowflake generation. So, there could be some light snow mixed with the rain overnight as the system exits. Then, high pressure will build across the Ohio Valley, with the active storm track being pushed well to our south. The only question is whether a southern track system Thursday will be deep enough to increase moisture and rain potential across the Ohio and Tennessee Valleys as it tracks across the Gulf States. Rain probabilities are low for Thursday, with an overall slower trend noted in latest guidance. Will go with a dry forecast Tuesday through Thursday, with perhaps a slight rain chance across our south and southeast CWA just beyond the long-term period. The cold front that swings through the area early Sunday will not be followed by a cold air mass. Still expect temperatures in the 60s Sunday afternoon. However, the passage of the second front on Monday will bring a return to unseasonably cool conditions through Thursday. The good news is temperatures appear to moderate some through the work week. So, while highs in the 40s are expected Tuesday, highs Thursday appear to reach the middle 50s. && .Aviation (12Z TAF Issuance)... Issued at 645 AM EDT Fri Mar 29 2013 VFR conditions are expected for this TAF period. Mid and upper level clouds will continue to stream into the area this morning and continue through the day as an upper level shortwave passes through south central KY. This wave looks to bring precip in the form of rain showers to BWG today. These showers have made it into the BWG terminal with the main push of moisture progged to occur from roughly 13Z-20Z. SDF/LEX still look to remain dry although will need to monitor the northern extent of the precip shield to make sure it doesn`t creep into SDF. The 0Z NAM indicates MVFR conditions will develop at BWG today, but feel it is an outlier at this point compared to other model runs and upstream obs. Still will need to watch BWG for some cig/vsby restrictions today. Winds will be hard to pin down throughout the TAF period. Generally they will remain light (under 5 kts). Variable winds can be expected during the early morning hours and again tonight. Think that the predominant wind direction at BWG this afternoon will be SSE with SDF/LEX winds predominantly SSW. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Short Term.......AMS Long Term........MJP Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
317 AM EDT FRI MAR 29 2013 .Short Term (Now - Saturday)... Issued at 300 AM EDT Fri Mar 29 2013 An upper level shortwave and weak sfc boundary were located to our WSW early this morning producing showers and t-storms from eastern KS to western KY. The latest RAP model guidance seems to be handling this area of precip quite well, so have relied on it for short term POPs. Rain showers look likely across portions of south central KY this morning before moving south of the area into TN this afternoon. Think that better lapse rates out west are producing the t-storms with this wave and do not anticipate those better lapse rates to translate eastward so will not include thunder in this forecast. For high temperatures today, have gone with mid 50s over southern Indiana and north central KY which will see less cloud cover overall and no precip. Lower 50s can be expected for highs over south central KY where rain is anticipated. Tonight sfc high pressure will quickly work in from the north allowing for dry conditions and only partly cloudy skies across southern IN and northern KY. Went with a decent temp gradient due to cloud cover with low to mid 30s for lows over southern IN/northern KY to upper 30s and lower 40s over south central KY. The next push of moisture doesn`t look to arrive until late Sat afternoon or evening as a warm front pushes into south central KY. Therefore, limited POP chances to just the afternoon hours over south central KY for Sat. The rest of the area should be dry and warm up quite nicely. With only partly cloudy skies anticipated during the morning and early afternoon, went with high temps in the low to mid 60s. .Long Term (Saturday Night - Thursday)... Issued at 300 AM EDT Fri Mar 29 2013 Cold front number one will be fast approaching from the northwest Saturday night. Rain and a few embedded rumbles of thunder will overspread the forecast area Saturday night and through the morning hours Sunday. Rain chances will diminish from west to east late Sunday morning, with a dry period anticipated from roughly Sunday afternoon through Sunday night. A second cold front will quickly enter the forecast area from the north Monday and sag south through Monday night. Expect rain chances to increase through the day Monday and rain should exit the southern CWA by Tuesday morning. Temperatures will fall behind the front Monday night and soundings indicate the potential for some smaller ice crystal growth. It appears the loss of moisture/ice crystals within the dendritic growth layer will limit large snowflake generation. So, there could be some light snow mixed with the rain overnight as the system exits. Then, high pressure will build across the Ohio Valley, with the active storm track being pushed well to our south. The only question is whether a southern track system Thursday will be deep enough to increase moisture and rain potential across the Ohio and Tennessee Valleys as it tracks across the Gulf States. Rain probabilities are low for Thursday, with an overall slower trend noted in latest guidance. Will go with a dry forecast Tuesday through Thursday, with perhaps a slight rain chance across our south and southeast CWA just beyond the long-term period. The cold front that swings through the area early Sunday will not be followed by a cold air mass. Still expect temperatures in the 60s Sunday afternoon. However, the passage of the second front on Monday will bring a return to unseasonably cool conditions through Thursday. The good news is temperatures appear to moderate some through the work week. So, while highs in the 40s are expected Tuesday, highs Thursday appear to reach the middle 50s. && .Aviation (06Z TAF Issuance)... Issued at 105 AM EDT Fri Mar 29 2013 VFR conditions are expected for this TAF period. Mid and upper level clouds will continue to stream into the area overnight and continue through the day as an upper level shortwave passes through south central KY. This wave looks to bring precip in the form of rain showers to BWG today. These showers have made it as far east as western KY and a few will likely make it into the BWG TAF within the next 1-3 hrs. The main push of moisture should hold off until later this morning with light steady rain showers expected from roughly 13Z-20Z. SDF/LEX still look to remain dry. The 0Z NAM indicates MVFR conditions will develop at BWG today, but feel it is an outlier at this point compared to other model runs and upstream obs. Still will need to watch BWG for some cig/vsby restrictions today. Winds will be hard to pin down throughout the TAF period. Generally they will remain light (under 5 kts). Variable winds can be expected during the early morning hours and again this evening. Think that the predominant wind direction at BWG this afternoon will be SSE with SDF/LEX winds predominantly SSW. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Short Term.......AMS Long Term........MJP Aviation.........AMS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
840 PM EDT SAT MAR 30 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 453 PM EDT SAT MAR 30 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER THE FAR WRN CONUS INTO WRN CANADA WHILE DOWNSTREAM TROF WAS AMPLIFYING S THRU CNTRL CANADA INTO THE NCNTRL CONUS. WITHIN THE DEEPENING TROF...A SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES HAS BROUGHT A BAND OF PCPN TO UPPER MI TODAY. PCPN WAS MAINLY RAIN OVER THE W...BUT MIXED WITH/CHANGED TO SNOW OVER THE CNTRL/E. SNOW WAS MDT/HVY ACROSS IRON/DICKINSON COUNTIES WHERE A FEW INCHES OF WET SNOW ACCUMULATION HAS BEEN REPORTED. THE HEAVIER SNOW IS NOW STREAKING E TOWARD LUCE COUNTY. BACKEDGE OF THE MAIN PCPN AREA WAS OVER CNTRL UPPER MI AS OF 20Z. WITH DEPARTURE OF THIS AREA OF PCPN...ATTENTION IN THE SHORT TERM SHIFTS TO SHORTWAVE DIGGING SHARPLY INTO THE UPPER GREAT LAKES LATE TONIGHT/SUN AND THE INCREASINGLY COLDER AIR IT WILL BRING. INCORPORATING EXTRAPOLATION FOR ENDING PCPN...EXPECT STEADIER PCPN TO EXIT THE ERN FCST AREA AROUND 03Z WITH ALL OF THE AREA DRY BY 06Z. MAY SEE AN INCH OR SO OF WET SNOW OVER THE INTERIOR E DURING THE LATE AFTN. LOW CLOUDS AND FOG WERE PRESENT EARLY TODAY BEHIND THE PCPN AREA IN MN...AND WILL PROBABLY SEE SOME OF THAT AND PERHAPS SOME -DZ IN MAINLY AREAS THAT SEE UPSLOPING WITH A W WIND FOR A FEW HRS AFTER PCPN ENDS AND BEFORE THE ONSET OF CAA OVERNIGHT INCREASES LOW-LEVEL MIXING. BY 12Z...850MB TEMPS ARE PROGGED AT -8/-9C OVER WRN LAKE SUPERIOR. WHILE THAT IS SHY OF THE THRESHOLD FOR LES GIVEN WATER TEMPS AROUND 1C...SRN EDGE OF DEEP LAYER FORCING ASSOCIATED WITH APPROACHING SHORTWAVE AND PRESENCE OF CYCLONIC FLOW MAY GENERATE SOME LAKE ENHANCED -SHSN OVER NW UPPER MI LATE IN THE NIGHT. DURING THE DAY SUN...SHORTWAVE DIGS S ACROSS THE UPPER GREAT LAKES...BRINGING 100-120M HEIGHT FALLS AT 500MB. ALTHOUGH BEST DEEP LAYER FORCING PASSES N AND NE OF UPPER MI...DEEP CYCLONIC FLOW AND SUFFICIENT INCREASE IN MOISTURE DEPTH TO AROUND 10KFT SUGGESTS SCT TO NMRS -SHSN ARE A GOOD BET. LATE MAR SOLAR INSOLATION WILL ADD A DIURNAL COMPONENT TO -SHSN COVERAGE OVER THE INTERIOR WHILE DISRUPTING NORMAL LAKE EFFECT PROCESSES THAT WOULD BE GETTING UNDERWAY OVER LAKE SUPERIOR AS 850MB TEMPS FALL TOWARD -14C IN THE AFTN. ALTHOUGH COLUMN BECOMES MORE SUPPORTIVE OF SNOW AS PTYPE AS THE DAY PROGRESSES...DAYTIME HEATING SHOULD RESULT IN MIX WITH -SHRA INTO THE MID AFTN OVER THE SCNTRL. WINDS MAY APPROACH ADVY CRITERIA OVER THE KEWEENAW...BUT WITH MIXED LAYER WINDS LOW/MID 30KT AT MOST AND ONLY MODEST PRES RISES APPROACHING FROM THE NW...DO NOT ANTICIPATE WIND ADVY BEING NEEDED AT THIS POINT. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 453 PM EDT SAT MAR 30 2013 CONTINUE TO SEE GOOD AGREEMENT FROM GFS/ECMWF/GEM-NH IN OVERALL LARGER SCALE PATTERN FOR THE LONG TERM. DEEP AND COLD TROUGHING INITIALLY IN PLACE LEADS TO A PERIOD OF LAKE ENHANCED SNOW FOR SNOWBELTS FAVORED BY NORTHWEST WINDS SUNDAY NIGHT THROUGH TUESDAY MORNING. FOCUSED IN ON MORE OF THE DETAILS THIS GO AROUND. WAVE THAT MOVES THROUGH TO BRING IN THE TROUGHING ON SUNDAY NIGHT PRETTY SHARP UPSTREAM THIS MORNING OVER NORTHERN MANITOBA INTO NINAVUT. WENT WITH MODELS THAT WERE SHARPER WITH H5 WAVE AND RESULTING SFC TROUGH DROPPING ACROSS LK SUPERIOR LATE SUNDAY AFTN INTO SUNDAY EVENING. SOUNDINGS DURING THAT TIME INDICATE MORE OF A WIDESPREAD SNOW JUST IN WAKE OF FRONT...ALONG WITH PUSH OF NORTH WINDS TO AROUND 40 MPH. EXPANDED POPS OVER MUCH OF THE NORTH HALF OF CWA SUNDAY EVENING. SNOWFALL RATES MAY EXCEED 1"/HOUR FOR A COUPLE HOURS AS THIS BAND OF SNOW MOVES THROUGH. BY MIDNIGHT...MODELS INDICATE WIDESPREAD DEEPER H8-H7 MOISTURE DEPARTS LEAVING MOST OF THE SNOW SET UP OVER HIGHER TERRAIN OF WEST AND NCNTRL CWA AND ALSO FOR SNOWBELTS FROM MUNISING TO NEWBERRY. LAKE ENHANCED SNOW THAT OCCURS FOR THOSE SNOWBELTS LATER SUNDAY NIGHT INTO MONDAY MAY BE HEAVY AT TIMES AS SOUNDINGS INDICATE MOISTURE THROUGH H8 AND INVERSION HEIGHTS UP TO 10KFT. OVER-WATER INSTABILITY IS SUFFICIENT AS H85 TEMPS ARE AROUND -16C. AT FIRST GLANCE SEEMS LIKE LAKE EFFECT SNOW WATCH MAY BE IN ORDER. THERE ARE A COUPLE NEGATIVE FACTORS THOUGH THAT PROHIBITED ISSUANCE OF WATCH. FIRST OF WHICH IS DRYING NOTED BLO 5KFT LEADING TO MORE OF AN INVERTED-V LOOK TO SOUNDING...ESPECIALLY OVERNIGHT SUNDAY NIGHT INTO MONDAY. SECOND NEGATIVE IS SHEAR IN THE MOIST CONVECTIVE LAYER AT LEAST TO START OUT...BUT THIS DOES EASE LATE SUNDAY NIGHT THOUGH BLYR WINDS STAY UP TO 30 KTS FROM THE NORTHWEST. BEST SHOT AT HEAVIER SNOW WOULD BE THROUGH MID-LATE MORNING ON MONDAY AS DAYTIME HEATING/HIGHER SUN ANGLE WILL ACT TO DISRUPT SNOW SHOWERS AS THE DAY GOES ON. LAKE EFFECT SNOW SHOWERS MAY INCREASE AGAIN MONDAY NIGHT. DUE TO COMBO OF THE LAKE EFFECT SNOWS AND BLOWING SNOW...LIKELY WILL NEED ADVISORY HEADLINES INTO MONDAY NIGHT AND TUESDAY MORNING. SINCE THERE IS NOT MUCH BLOCKINESS DOWNSTREAM...DEEP TROUGH WILL REMAIN PROGRESSIVE WITH RISING HEIGHTS DEVELOPING OVER UPPER LAKES AS EARLY AS TUESDAY. SUFFICIENTLY COLD AND MOIST ENOUGH FOR LK EFFECT BUT LARGER SCALE NEGATIVES SHOULD RESULT IN DIMINISHING TREND TO LK EFFECT BY TUESDAY AFTN. POPS REFLECTED THIS FOR MOST PART...JUST NEEDED SOME MINOR TWEAKS. AFTER PARTIAL CLEARING AND WARMER CONDITIONS FOR WEDNESDAY ANOTHER SHORTWAVE TROUGH THEN SWINGS ACROSS MANITOBA AND NORTHERN ONTARIO WEDNESDAY NIGHT AND THURSDAY. ASSOCIATED COLD FRONT MOVES ACROSS UPPER LAKES ON THURSDAY. DPROG/DT FROM EARLIER GFS/ECMWF RUNS INDICATED A SLOWER TREND WITH SHORTWAVE POINTING TO MOST OF PRECIPITATION FROM THE SYSTEM TAKING PLACE ON THURSDAY OVER UPPER MICHIGAN. 12Z GFS REALLY SPED UP AND SEEMS OUT OF PLACE NOW WITH PCPN TIMING. 1000-500MB AND 1000-850MB THICKNESSES INDICATE MIX OF RAIN/SNOW. LIMITED MOISTURE WILL KEEP AMOUNTS LIGHT. COOLER AND DRY IN WAKE OF COLD FRONT INTO FRIDAY. QUESTIONS INCREASE FOR NEXT WEEKEND. GOOD BET THAT UPPER LAKES WILL BE ON THE SOUTHERN EDGE OF STRONGER JET STREAM RIDING ALONG SOUTHERN TIER OF CANADA. AS MID-LEVEL FLOW BECOMES MORE WESTERLY MODELS INDICATE SHORTWAVE TROUGH AND SFC-H85 LOWS VCNTY OF NORTHERN PLAINS INTO WESTERN GREAT LAKES BY 12Z SATURDAY. POOR CONSISTENCY ON WHERE SFC-H85 LOWS SET UP THOUGH. LATEST ECMWF/GFS CONTINUE TO INDICATE FARTHER NORTH LOW WITH QPF INTO UPPER LAKES BY NEXT SATURDAY WHILE EARLIER RUNS KEPT MOST OF QPF TO SOUTH. 1000-500MB AND 1000-850MB THICKNESSES AT OR ABOVE 540DAM AND 1305M AND H85 TEMPS OVER 0C INTO WESTERN CWA INDICATE MIX OF RAIN AND SNOW. CONSENSUS OF MODELS CAME UP WITH HIGHER CHANCE POPS WHICH WILL WORK IF THE NORTHERN TREND CONTINUES IN THE MODELS. JUST CANNOT SEEM TO SHAKE THIS COOLER AND ACTIVE WEATHER PATTERN AS WE HEAD INTO THE FIRST WEEK OF APRIL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 808 PM EDT SAT MAR 30 2013 AREA OF PCPN ASSOCIATED WITH LOW PRES TROF HAS SHIFTED E OF THE TAF SITES. PER SATELLITE IMAGERY AND PER SFC OBS DRIER AIR ADVECTING IN BEHIND TROUGH HAS ERODED LOW CLOUDS AND FOG OVER KIWD AND KCMX WHERE CONDITIONS SHOULD BE VFR AND MVFR FOR A TIME THIS EVENING RESPECTIVELY. DRIER AIR WILL BE SLOWER TO REACH KSAW WHERE LIFR CONDITIONS WILL SLOWLY IMPROVE TO IFR LATE THIS EVENING/OVERNIGHT. APPROACH OF NEXT DISTURBANCE WILL BRING A RETURN TO MVFR CONDITIONS AT KIWD OVERNIGHT. EXPECT INCREASING POTENTIAL OF -SHSN AND CONTINUED MVFR CONDITIONS AT KIWD/KCMX LATE TONIGHT INTO SUNDAY AS DISTURBANCE ARRIVES. GUSTY WNW WINDS WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE LATE MORNING. AT KSAW...ONSET OF WESTERLY WIND WILL FAVOR DOWNSLOPE DRYING AFT 12Z SUNDAY SO EXPECT CIGS TO IMPROVE TO MVFR AT THAT TIME. WNW AND COLD ADVECTION BEHIND FRONT WILL BRING A CHANCE OF -SHSN SUNDAY AFTERNOON AT KSAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 453 PM EDT SAT MAR 30 2013 STRONGER DISTURBANCE MOVING INTO THE UPPER LAKES SUN WILL USHER COLDER AIR OVER LAKE SUPERIOR WHILE SFC LOW PRES DEEPENS TO THE E AND NE. THIS WILL RESULT IN STRENGTHENING NW WINDS ACROSS THE LAKE. IN FACT...NW GALES ARE EXPECTED TO DEVELOP OVER CNTRL AND ERN LAKE SUPERIOR SUN AFTN. UNDER SLOW MOVING WEATHER PATTERN WITH COLD UNSTABLE AIR OVER THE LAKE...THE GALES WILL LIKELY CONTINUE INTO TUE. FREEZING SPRAY WILL ALSO DEVELOP SUN NIGHT AND LINGER INTO TUE AS UNSEASONABLY COLD AIR SETTLES OVER THE AREA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 2 PM SUNDAY TO 8 PM EDT TUESDAY FOR LSZ264>267. GALE WARNING FROM 2 PM SUNDAY TO 6 PM EDT MONDAY FOR LSZ244-245- 249>251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...VOSS MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GAYLORD MI
130 PM EDT FRI MAR 29 2013 .SYNOPSIS... ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND. THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE EFFECT SNOW SHOWERS AND WINDY CONDITIONS. && .UPDATE... ISSUED AT 129 PM EDT FRI MAR 29 2013 STRATUS IS GONE OVER EASTERN UPPER. A FEW CU HAVE FIRED SOUTH OF CAD/HTL...AND INLAND OF OSC/TAWAS...OTHERWISE SKIES ARE CLEAR. OSC BRIEFLY TWEAKED UP TO 47F...BUT A LAKE BREEZE HAS BROUGHT THEM BACK TO EARTH. MOST SITES NEAR 40S TO THE MID 40S...SOME OF THE MORE MARITIME LOCALES STILL STUCK IN THE 30S. NO MAJOR CHANGES MADE. UPDATE ISSUED AT 959 AM EDT FRI MAR 29 2013 PATCHY STRATUS CONTINUES IN EASTERN CHIPPEWA CO AND OVER WHITEFISH BAY...THOUGH HAS BROKEN UP SOMEWHAT OVER THE SAULTS PROPER. THE STRATUS SHOULD ERODE AND MIX OUT OVER THE NEXT 3 HOURS. TEMPS HAVE REBOUNDED INTO THE MID 20S TO MID 30S...DO NOT PLAN ON ANY SIGNIFICANT CHANGES TO THE MAX TEMP FORECAST. UPDATE ISSUED AT 613 AM EDT FRI MAR 29 2013 CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH IMPACT WEATHER POTENTIAL: NONE. OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY! THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES REFREEZE. TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT /DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES... WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE LESS. TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 329 AM EDT FRI MAR 29 2013 SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z. SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO CONTINUE THE LIKELY POPS. SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT. EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS -14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT. THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 129 PM EDT FRI MAR 29 2013 VFR. CLOUDS INCREASING ON SATURDAY. HIGH PRESSURE OVER THE PRESSURE PROVIDING NEARLY CLEAR SKIES THIS AFTERNOON AND MOST OF TONIGHT. THE HIGH MOVES EAST TONIGHT AND MORE RAPIDLY SO ON SATURDAY...ALLOWING CLOUDS TO FILTER IN FROM THE WEST. ANY PRECIP THREAT WILL WAIT UNTIL AFTER 18Z SATURDAY. LIGHT NW WINDS TODAY...INTERRUPTED BY LAKE BREEZES. LIGHT WINDS TONIGHT...SOUTHERLY WINDS SATURDAY. && .MARINE... ISSUED AT 329 AM EDT FRI MAR 29 2013 SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM THE WEST. HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE SOUTHEAST TO PRESQUE ISLE LIGHT/. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JZ SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...JZ MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
959 AM EDT FRI MAR 29 2013 .SYNOPSIS... ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND. THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE EFFECT SNOW SHOWERS AND WINDY CONDITIONS. && .UPDATE... ISSUED AT 959 AM EDT FRI MAR 29 2013 PATCHY STRATUS CONTINUES IN EASTERN CHIPPEWA CO AND OVER WHITEFISH BAY...THOUGH HAS BROKEN UP SOMEWHAT OVER THE SAULTS PROPER. THE STRATUS SHOULD ERODE AND MIX OUT OVER THE NEXT 3 HOURS. TEMPS HAVE REBOUNDED INTO THE MID 20S TO MID 30S...DO NOT PLAN ON ANY SIGNIFICANT CHANGES TO THE MAX TEMP FORECAST. UPDATE ISSUED AT 613 AM EDT FRI MAR 29 2013 CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH IMPACT WEATHER POTENTIAL: NONE. OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY! THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES REFREEZE. TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT /DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES... WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE LESS. TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 329 AM EDT FRI MAR 29 2013 SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z. SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO CONTINUE THE LIKELY POPS. SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT. EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS -14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT. THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 638 AM EDT FRI MAR 29 2013 SUMMARY: HIGH PRESSURE CENTERED JUST WEST OF THE WESTERN GREAT LAKES WILL SHIFT EAST...MOVING OVERHEAD THROUGH MOST OF THE UPCOMING TAF PERIOD...ALLOWING FOR CONTINUED GOOD FLYING CONDITIONS. RESTRICTIONS: NONE EXPECTED THROUGH THE TAF PERIOD. CONFIDENCE HIGH. WINDS: CALM WINDS WILL BECOME NORTHWEST 5-10KTS BY MID-LATE MORNING AND THROUGH THE AFTERNOON BEFORE RETURNING TO CALM TONIGHT. A LAKE BREEZE MAY CAUSE THESE NORTHWEST WINDS TO DIE OFF/SHIFT WEAK SOUTHEAST AT APN BY MID/LATE AFTERNOON. && .MARINE... ISSUED AT 329 AM EDT FRI MAR 29 2013 SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM THE WEST. HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE SOUTHEAST TO PRESQUE ISLE LIGHT/. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JZ SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...ARNOTT MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
639 AM EDT FRI MAR 29 2013 .SYNOPSIS... ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND. THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE EFFECT SNOW SHOWERS AND WINDY CONDITIONS. && .UPDATE... ISSUED AT 613 AM EDT FRI MAR 29 2013 CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH IMPACT WEATHER POTENTIAL: NONE. OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY! THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES REFREEZE. TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT /DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES... WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE LESS. TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 329 AM EDT FRI MAR 29 2013 SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z. SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO CONTINUE THE LIKELY POPS. SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT. EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS -14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT. THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 638 AM EDT FRI MAR 29 2013 SUMMARY: HIGH PRESSURE CENTERED JUST WEST OF THE WESTERN GREAT LAKES WILL SHIFT EAST...MOVING OVERHEAD THROUGH MOST OF THE UPCOMING TAF PERIOD...ALLOWING FOR CONTINUED GOOD FLYING CONDITIONS. RESTRICTIONS: NONE EXPECTED THROUGH THE TAF PERIOD. CONFIDENCE HIGH. WINDS: CALM WINDS WILL BECOME NORTHWEST 5-10KTS BY MID-LATE MORNING AND THROUGH THE AFTERNOON BEFORE RETURNING TO CALM TONIGHT. A LAKE BREEZE MAY CAUSE THESE NORTHWEST WINDS TO DIE OFF/SHIFT WEAK SOUTHEAST AT APN BY MID/LATE AFTERNOON. && .MARINE... ISSUED AT 329 AM EDT FRI MAR 29 2013 SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM THE WEST. HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE SOUTHEAST TO PRESQUE ISLE LIGHT/. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...ARNOTT SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...ARNOTT MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
619 AM EDT FRI MAR 29 2013 .SYNOPSIS... ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH PRESSURE WILL ADVANCE FROM THE UPPER MIDWEST THROUGH THE GREAT LAKES TO ROUND OUT TODAY. THIS PATTERN WILL BRING SUNSHINE THROUGH THE FIRST HALF OF SATURDAY. TEMPERATURES WILL ALSO FINALLY...ALTHOUGH BRIEFLY...WARM ABOVE NORMAL FOR THE FIRST HALF OF THE WEEKEND. THAT TREND WILL BE SHORT LIVED...AS A STRONG COLD FRONT ARRIVES SATURDAY NIGHT...WITH A ROUND OF RAIN OR SNOW SHOWERS LIKELY. AS THE FRONT PASSES...MUCH COLDER WEATHER WILL ARRIVE LATER SUNDAY AND STICK AROUND THROUGH AT LEAST TUESDAY...WITH PERIODIC LAKE EFFECT SNOW SHOWERS AND WINDY CONDITIONS. && .UPDATE... ISSUED AT 613 AM EDT FRI MAR 29 2013 CHANGES THIS HOUR: COULDN/T QUITE GET THROUGH THE OVERNIGHT WITHOUT DEALING WITH SOME STRATUS. A PATCH HAS POPPED UP OVER THE PAST HOUR FROM KANJ NORTH INTO THE HIGH TERRAIN EAST OF WHITEFISH BAY ACROSS THE BORDER IN ONTARIO. NEAR TERM RUC PROGS SUGGEST THAT SOMEWHAT ENHANCED H9 MOISTURE FROM THIS AREA EAST WILL MOVE EAST AND AWAY FROM THE REGION THIS MORNING. DON/T EXPECT THIS TO GET TOO OUT OF HAND/WIDESPREAD...BUT WILL CARRY SOME ADDITIONAL CLOUDINESS THROUGH THE NEXT FEW HOURS AS EARLY MORNING INVERSION WILL ALLOW ANYTHING THAT DEVELOPS TO PERSIST FOR A TIME. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 329 AM EDT FRI MAR 29 2013 HIGH IMPACT WEATHER POTENTIAL: NONE. OVERVIEW: EARLY MORNING WATER VAPOR IMAGERY REVEALS RECENT BLOCKING OVER EASTERN CANADA RETREATING EAST AS BROAD NORTHWEST FLOW BEGINS TO TAKE OVER ALOFT ACROSS THE GREAT LAKES REGION. THE CLOSED HIGH ASSOCIATED WITH THIS BLOCK HAS OPENED UP...AND WAS OVERHEAD AS SHORTWAVE RIDGING YESTERDAY AND HAS NOW PUSHED INTO THE NORTHEASTERN CONUS AS OF THIS MORNING. MOVING DOWN TO THE SURFACE...A MODEST SURFACE RIDGE AXIS IS DRAPED FROM JUST WEST OF THE WESTERN LAKES INTO INDIANA/KENTUCKY...WHICH HAS PROVIDED CALM/QUIET WEATHER ACROSS THE GREAT LAKES REGION. 00Z APX RAOB SHOWED -4C AT H8...JUST ABOUT NORMAL FOR THIS TIME OF YEAR WITH OUR AVERAGE TEMPERATURE FOR THE DATE YESTERDAY SIMILARLY CLOSE TO NORMAL. WITH THIS HIGH OVERHEAD AND THE MAJORITY OF ANY JET ENERGY RESIDING OVER THE SOUTHEASTERN STATES...THE WEATHER LOOKS QUIET THROUGH THE SHORT TERM PORTION OF THE FORECAST...BUT THE AFOREMENTIONED BREAKING DOWN OF THE BLOCK OVER CANADA PORTENDS THAT THIS QUIET STRETCH OF WEATHER WILL BE COMING TO AN END SOON...SO DON/T GET USED TO WHAT YOU SEE TODAY! THROUGH DAYBREAK: TERRIFIC RADIATIONAL COOLING CONDITIONS ALLOWING SOME SPOTS TO REACH 20F AS OF THIS WRITING...WITH A WEAK WIND KEEPING SOME HIGHER TERRAIN SPOTS AS WELL AS THE NE LOWER COAST IN THE UPPER 20S TO AROUND 30 UNDER CLEAR SKIES. LITTLE CHANGE THROUGH DAYBREAK...WITH SOME LOCAL SLICK SPOTS LIKELY AS AFTERNOON PUDDLES REFREEZE. TODAY: WEAK SHORTWAVE TROUGH NOW EXITING TO THE SOUTHEAST OF THE REGION WILL ALLOW FOR GRADUALLY BUILDING MID LEVEL HEIGHTS /ALONG WITH MID LEVEL NVA/ TODAY WITH THE RIDGE OF SURFACE HIGH PRESSURE SLIDING EAST INTO THE REGION. LLEVEL TRAJECTORIES SHOW TODAY/S AIRMASS ARRIVING FROM WESTERN ONTARIO 24 HOURS PREVIOUSLY...AND A LOOK AT YESTERDAY/S CONDITIONS THERE SHOW NO CUMULUS DEVELOPMENT /DEWPOINTS FALLING INTO THE LOWER-MID TEENS/ ALONG WITH LOWER 40S FOR HIGHS. GIVEN THE OVERHEAD HIGH PRESSURE AND NVA...WILL ALLOW FOR SOME WARMING TO THIS AIRMASS THROUGH SUBSIDENCE WHICH SUGGESTS TRENDING TOWARDS THE WARMER ECMWF-MOS GUIDANCE TODAY...YIELDING HIGHS IN THE MID-UPPER 40S MOST LOCATIONS UNDER SUNNY SKIES... WARMEST SOUTHEASTERN AREAS WHERE LAKE INFLUENCE ON TEMPS WILL BE LESS. TONIGHT: HIGH PRESSURE SETTLES OVERHEAD WITH SHORT-WAVE RIDGING CONTINUING/SHARPENING AT MID LEVELS IN RESPONSE TO OUR NEXT WEATHER MAKER DROPPING SOUTH OUT OF CENTRAL CANADA. THIS WILL LIKELY SPREAD SOME HIGH CLOUDINESS INTO THE REGION AFTER MIDNIGHT...BUT FOR THE MOST PART EXPECT ANOTHER CALM/CLEAR/QUIET NIGHT WITH TERRIFIC RADIATIONAL COOLING CONDITIONS YET AGAIN. AFTERNOON CROSSOVER TEMPS WILL LIKELY BE IN THE LOWER-MIDDLE TEENS...SO LOWS SHOULD HAVE NO PROBLEM FALLING INTO THE MIDDLE-UPPER TEENS IN THE COLD SPOTS YET AGAIN WITH LOWS GENERALLY IN THE LOWER 20S ELSEWHERE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 329 AM EDT FRI MAR 29 2013 SATURDAY...AS THE SFC HIGH MOVES EAST, THE COLD FRONT FROM THE WEST BEARS DOWN ON THE FORECAST AREA. AIDING THE COLD FRONT IS THE 500 MB SHORTWAVE TROUGH THAT IS CHASING THE RIDGE EAST AS WELL. THE MORNING LOOKS TO REMAIN DRY AS THE MOISTURE AT 850 MB AND IN THE 700-500 MB LAYER TAKES UNTIL AROUND 18Z TO BEGIN GETTING MOIST ENOUGH TO SUPPORT PRECIPITATION. THE PROFILE WOULD SUGGEST THAT THE PRECIPITATION WOULD BE ALL RAIN THROUGH 00Z. SATURDAY NIGHT...MOISTURE CONTINUES OVER THE REGION AND THE PROFILES BEGIN TO MOVE TOWARD 0C SO THAT THERE WILL BE A MIX IN E UPPER AND PROBABLY RAIN IN N LOWER. THE PROFILES DON`T CHANGE MUCH OVERNIGHT SO THAT A MIX IS WHAT WILL BE EXPECTED. ALSO, THE 700-500 MB LAYER BEGINS TO DRY OUT SIGNIFICANTLY ENOUGH THAT IT MAY STOP PRECIPITATING. SO WILL GO WITH THE CHANCE POPS IN E UPPER AND OVER LAKE MICHIGAN. STILL LOTS OF MOISTURE OVER N LOWER AND LAKE HURON TO CONTINUE THE LIKELY POPS. SUNDAY...THE MOISTURE CONTINUES TO MOVE EAST, WITH COLD AIR SPILLING INTO THE FORECAST AREA. AS THE COLD AIR MOVES IN THE MOISTURE BEGINS TO MOVE INTO THE REGION WITH SATURATION REACHING -10C. THIS GETS THE LIGHT SNOW/FLURRIES STARTED AS THE STABILITY BEGINS TO DECREASE AND UNDER THE 500 MB LOW AND SHORTWAVES ROTATING AROUND IT. OVERNIGHT, THE 850 MB TEMPERATURES FALL TO AROUND -13C ON THE ECMWF BY 12Z. THE GFS IS SIGNIFICANTLY COLDER (-17C) AND WOULD PRODUCE LES FAIRLY WELL WITH THE 500 MB LOW. WILL HEDGE PESSIMISTIC AS THIS SEASON HAS REMAINED COLDER THAN FIRST THOUGHT. EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, LOOKS LIKE THE TEMPERATURES FALL ENOUGH TO HAVE LES ON BOTH MODELS AS THE ECMWF HAS -14C AT 850 MB BY 00Z. EARLIER IN THE WEEK, THE WINDS LOOKED STRONGER, NOW IT LOOKS BREEZY. WILL CONTINUE THE GUSTY WINDS IN THE HWO. TUESDAY, AS THE SFC HIGH BEGINS TO MOVE INTO THE REGION, THE 850 MB TEMPERATURES BEGIN TO WARM SLIGHTLY, JUST ENOUGH THAT WE MAY LOSE THE INSTABILITY NEEDED FOR THE LES. THIS CONTINUES INTO THE NIGHT SO WOULD EXPECT THAT THE SNOW WOULD STOP. 00Z ECMWF SAYS THAT IT SHOULD. WEDNESDAY, HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, THE ANOTHER COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE THROUGH THE REGION. ONE SOLUTION IS WARM ENOUGH FOR RAIN AND ONE COLD ENOUGH FOR SNOW. SO WILL GO WITH A MIX AT THIS POINT. THURSDAY, THINK THAT THE GFS IS A LITTLE TOO WET AT 850 MB AND THINK THAT THE THE ECMWF HAS THE RIGHT IDEA, THAT IS IT IS IN LINE WITH THE CURRENT FORECAST SO WILL CONTINUE THE DRY DAY AND NIGHT AT HIGH PRESSURE BEGINS TO BUILD INTO THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 129 AM EDT FRI MAR 29 2013 SUMMARY: HIGH PRESSURE JUST WEST OF THE GREAT LAKES REGION WILL PUSH OVERHEAD BRINGING VERY QUIET CONDITIONS THROUGH THE UPCOMING TAF PERIOD. OUTSIDE OF A FEW HIGH CLOUDS...EXPECT CLEAR SKIES THROUGH THE TAF PERIOD. RESTRICTIONS: NONE EXPECTED THROUGH THE TAF PERIOD. CONFIDENCE HIGH. WINDS: CALM WINDS THROUGH DAYBREAK WILL BECOME NORTHWEST 5-10KTS BY MID-LATE MORNING AND THROUGH THE AFTERNOON BEFORE RETURNING TO CALM FRIDAY NIGHT. A LAKE BREEZE MAY CAUSE THESE NORTHWEST WINDS TO DIE OFF/SHIFT WEAK SOUTHEAST AT APN BY MID/LATE AFTERNOON. && .MARINE... ISSUED AT 329 AM EDT FRI MAR 29 2013 SUMMARY: HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION/S WEATHER THROUGH SATURDAY WITH QUIET CONDITIONS OVER THE LAKES. A COLD FRONT WILL APPROACH SUNDAY...BRINGING STRENGTHENING SOUTHERLY WINDS. IN IT/S WAKE...NORTHWEST WINDS WILL DEVELOP AND STRENGTHEN SUNDAY NIGHT INTO MONDAY WITH STRONG WINDS CONTINUING THROUGH TUESDAY BEFORE HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FROM THE WEST. HEADLINE POTENTIAL: SMALL CRAFT POTENTIAL UNDER SOUTHERLY FLOW SATURDAY WITH A PROLONGED PERIOD OF SMALL CRAFT WINDS DEVELOPING BEHIND A STRONG COLD FRONT SUNDAY NIGHT AND CONTINUING THROUGH NEXT TUESDAY. THERE IS SOME POTENTIAL FOR LOW-END GALE FORCE WINDS IN THE MONDAY-TUESDAY TIMEFRAME FOR NW FLOW FAVORED AREAS /NEAR WHITEFISH POINT AND ALONG THE LAKE HURON COAST FROM THE BRIDGE SOUTHEAST TO PRESQUE ISLE LIGHT/. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...ARNOTT SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...ARNOTT MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1003 PM CDT SAT MAR 30 2013 .UPDATE... DESPITE ELEVATED WIND SPEEDS ACROSS WRN AND SRN MN...DEW POINTS IN THE LOW-MID 30S IN AREAS WHERE DEEP SNOW PACK REMAINS HAS PROMOTED THE DEVELOPMENT OF AREAS OF FOG. WINDS HAVE ACTUALLY BECOME CALM ACROSS WRN WI UNDER CLEAR SKIES WHICH IS A BIT MORE CONCERNING AND A FEW OBS HAVE REPORTED VIS LESS THAN 1/2 MILE. DECIDED TO POST A DENSE FOG ADVISORY FOR THESE AREAS WHERE DENSE FOG HAD BEEN REPORTED EVEN LATE THIS AFTERNOON. ADDED AREAS OF FOG TO THE GRIDS OVER MUCH OF THE REST OF THE AREA...EXCEPT IN THE TC METRO AND NORTH ALONG I-35 WHERE VISIBILITIES ARE STILL 10 MILES. A COLD FRONT WILL PUSH THROUGH LATE TONIGHT. INCREASING CLOUDS...STRONGER WINDS...AND DRIER AIR WILL PUT AN END TO THE FOG THREAT BETWEEN 4 AND 7 AM FROM WEST TO EAST. && .PREV DISCUSSION.../ISSUED AT 237 PM CDT SAT MAR 30 2013/ OUR RECENT WARM-UP WILL BE COMING TO AN ABRUPT END TONIGHT... MAKING FOR A CHILLY START TO THE MONTH OF APRIL. IN THE BIG PICTURE... THE SEEMINGLY EVER- PRESENT EASTERN NORTH AMERICAN UPPER TROUGH WILL REASSERT ITSELF THROUGH THE FIRST PART OF THE UPCOMING WEEK... KEEPING UP IN NORTHWEST FLOW WITH PREDOMINANTLY COLD TEMPERATURES AND DRY WEATHER. HOWEVER... THE FLOW LOOKS TO FLATTEN OUT WITH A WARMING TREND OVER THE SECOND HALF OF THE WEEK. THE GFS AND ECMWF ARE ALSO SUGGESTING A MORE SUBSTANTIAL SHIFT IN THE PATTERN AS WE MOVE INTO THE FOLLOWING WEEK... WITH BOTH 12Z RUNS SUGGESTING A PROMINENT UPPER RIDGE OVER THE EASTERN CONUS BY THE 8TH AND 9TH OF APRIL... WITH A DEEP TROUGH OVER THE WESTERN CONUS DIGGING INTO FAR NORTHERN MEXICO. IF THAT WORKS OUT IT WOULD MEAN QUITE THE SUBSTANTIAL WARM-UP AS WE MOVE INTO THE START OF NEXT WEEK... WITH PERHAPS SOME INTERESTING WEATHER OVER THE CENTRAL PART OF THE COUNTY ONCE THE TROUGH EJECTS EAST. BUT... THAT/S OBVIOUSLY MANY DAYS AWAY... AND NOT ALL OF THE ENSEMBLE SOLUTIONS ARE IN LINE WITH THAT THINKING... SO WILL BE SOMETHING TO MULL OVER AND KEEP AN EYE ON THROUGH THE UPCOMING WEEK. IN THE MEANTIME... THINGS WILL BE FAIRLY QUIET AND COOL... WITH A FEW CHANCES FOR PCPN OVER THE UPCOMING SEVEN DAYS. PCPN ASSOCIATED WITH THE INITIAL FRONTAL PASSAGE HAS EXITED THE FORECAST AREA... WITH MAINLY PARTLY CLOUDY SKIES DEVELOPING IN ITS WAKE. HOWEVER... THERE IS AN AREA OF STRATUS AND FOG NORTH OF THE MINNESOTA RIVER VALLEY AND ALSO ACROSS THE NORTHWEST CWFA NEAR KAXN. THESE HAVE MIXED OUT SOME DURING THE DAY... BUT LIKELY WILL NOT GO AWAY ENTIRELY BEFORE NIGHT DESCENDS ON THE AREA. THE ARCTIC COLD FRONT WILL DROP ACROSS THE AREA TONIGHT BRINGING THE RETURN OF MUCH BELOW NORMAL TEMPERATURES FOR SEVERAL DAYS. EXPECT TO SEE SOME SNOW SHOWERS/FLURRIES SQUEEZED OUT AS THE FRONT MOVES THROUGH THE AREA... WITH PERHAPS SOME FLURRIES LINGERING OVER THE EAST INTO SUNDAY AS CYCLONIC FLOW AND DECENT BOUNDARY LAYER MOISTURE PERSIST. STRONG NORTHWEST WINDS WILL OCCUR BEHIND THE FRONT... ADDING AND ADDITIONAL NIP TO THE AIR THROUGH SUNDAY BEFORE ARCTIC HIGH PRESSURE BUILDS IN AND WORKS TO KEEP THINGS COLD AND DRY THROUGH WEDNESDAY. THE GFS AND ECMWF ARE IN REMARKABLY GOOD AGREEMENT THROUGH THE FORECAST PERIOD... WITH BOTH BRINGING US INTO RETURN FLOW ON THE BACKSIDE OF THE HIGH BY LATE WEDNESDAY... THEN SWINGING ANOTHER COLD FRONT THROUGH THE AREA ON THURSDAY. THAT FRONT WON/T HAVE NEARLY THE PUNCH AS TONIGHT/S... BUT WILL STILL DELAY THE RETURN OF MUCH WARMER TEMPERATURES. WE WILL ALSO SEE SOME CHANCE FOR LIGHT PCPN WEDNESDAY INTO EARLY THURSDAY AHEAD OF THE FRONT. WENT WITH CHANCES FOR RAIN AND SNOW AT THIS POINT... SINCE IT/S TOUGH TO SAY EXACTLY HOW MUCH WE/LL WARM BEFORE WE COOL DOWN SLIGHTLY AGAIN. CHANCES FOR MORE WIDESPREAD PCPN LOOK TO WORK INTO THE AREA LATE FRIDAY INTO SATURDAY AS WE GET INTO MORE ROBUST RETURN FLOW AND WARM ADVECTION AHEAD OF A SURFACE LOW THAT LOOKS TO LIFT NORTHEAST ACROSS MINNESOTA ON SATURDAY. ALLOWED FOR A TRANSITION FROM SNOW TO RAIN CHANCES WITH THAT SYSTEM... AND A SOMEWHAT EARLIER ARRIVAL THAN THE 12Z GUIDANCE WOULD SUGGEST. HOWEVER... PREVIOUS RUNS HAD A BIT MORE UNCERTAINTY WITH THE TIMING... SO WANTED TO TREND THINGS TOWARD A LATER START WITHOUT ENTIRELY DITCHING EARLIER FORECASTS. LATEST GUIDANCE WOULD ALSO SHIFT ANY CHANCE OF SNOW WELL NORTH ON SATURDAY... BUT KEPT SOME MIXED POTENTIAL OVER THE FAR NORTHERN CWFA TO AT LEAST ALLOW FOR SOME AT THE START OF THE DAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 06Z SUNDAY EVENING) WATCHING SHORTWAVE ACROSS THE DAKOTAS...ALONG WITH SECONDARY COLD FRONT MOVING SOUTH ACROSS SRN CAN. SREF IN PARTICULAR WANTING TO BREAK OUT SOME LIGHT PRECIP NORTH OF I-94 AS THE SHORT WAVE MOVES ACROSS THE AREA THIS EVENING. DEEP MOISTURE LOOKS TO BE LACKING...SO HELD ANY PRECIP MENTION IN TAFS TO A VC. AGAIN...LOCAL HOPWRF HI-RES ENSEMBLE LOOKS TO HAVE A GOOD HANDEL ON THIS FEATURE...SO USED IT TO TIME ANY VC MENTION IN TAFS. AS FOR THE COLD FRONT...UNLIKE THIS MORNINGS...THIS SECOND COLD FRONT WILL BRING WITH IT STRONG COLD AIR ADVECTION AND WITH THAT...A BANK OF POST FRONTAL STRATUS. 925-850 LAYER RH FROM THE NAM/RAP WAS USED TO TIME THESE CIGS INTO TERMINALS LATE TONIGHT. HOPWRF ENSEMBLE SHOWS MVFR CIGS RETURNING AS WELL...THOUGH SEVERAL HOURS EARLIER. GIVEN THE LACK OF MVFR CIGS CURRENTLY BEING OBS ACROSS CANADA...FAVORED THE SLOWER TIMING IN THESE TAFS. GIVEN STEEP LAPSE RATES EXPECTED SUNDAY...SHOULD HAVE NO PROBLEM MAINTAINING BKN-OVC STRATOCU...QUESTION IS HOW LOW. FOR NOW...PLAYED CONDS TO TREND TOWARD VFR BY THE AFTERNOON...BUT WE COULD VERY WELL HOLD CIGS IN THE 020-030 RANGE THROUGH MONDAY NIGHT. OUT IN WRN MN...BR/HZ OBS HAVE BEEN SLOW TO IMPROVE FROM REMNANT FOG THIS MORNING...AND WITH A WEAKNESS IN THE PRESSURE FIELD SEEN OUT THERE...FOLLOWED THE IDEA OF THE HRRR WITH MVFR OR LOWER VSBYS RETURNING FOR AXN/RWF AHEAD OF THE SECONDARY BOUNDARY...THOUGH CONFIDENCE IS LOW IN THIS SCENARIO PLAYING OUT AT RWF/AXN. FINALLY...ON WINDS...DEEP MIXING IS A CERTAINTY TOMORROW...AND CONFIDENCE IS QUITE HIGH IN NW WINDS GUSTING TO BETWEEN 25 AND 30 KTS MUCH OF THE DAY ON SUNDAY ACROSS MN. KMSP...CONFIDENCE PRETTY HIGH IN FORECAST THROUGH FIRST 8 HOURS...BUT DECREASES AFTER THAT AS NEXT UPPER LEVEL AND SFC BOUNDARY APPROACH. HELD BACK ON MVFR CIGS UNTIL 12Z...WHICH IS WHEN COLD AIR ADVECTION ARRIVES IN FORCE...THOUGH MVFR CONDS COULD COME IN EARLIER BASED ON HOPWRF PROBS FOR CIGS LESS THAN 3K FT. FOR NOW...KEPT CIGS ABOVE 017..BUT WOULD NOT RULE OUT CIGS BETWEEN 010 AND 015 SUNDAY MORNING. FOR NOW...SHOW CIGS TRENDING TO VFR...BUT CONFIDENCE NOT VERY HIGH ON THAT. CONFIDENCE IS HIGH HOWEVER IN THE WIND FORECAST AND IF ANYTHING...WOULD SAY THE SPEEDS ARE CONSERVATIVE...THOUGH A 300-320 DIRECTION WILL BE FAVORABLE FOR AIRPORT OPS. /OUTLOOK FOR KMSP/ MON...MVFR CIGS POSSIBLE. WINDS NW 15G25KTS. TUE...VFR. WIND NW 10 KTS. WED...VFR. WIND S 5-10 KTS BCMG 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...DENSE FOG ADVISORY UNTIL 7 AM CDT SUNDAY FOR WIZ015-016-025-027- 028. && $$ UPDATE...BORGHOFF PREV DISCUSSION...TRH AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
712 PM CDT SAT MAR 30 2013 .UPDATE... 00Z AVIATION DISCUSSION ADDED BELOW. && .PREVIOUS DISCUSSION... /ISSUED AT 237 PM CDT SAT MAR 30 2013/ OUR RECENT WARM-UP WILL BE COMING TO AN ABRUPT END TONIGHT... MAKING FOR A CHILLY START TO THE MONTH OF APRIL. IN THE BIG PICTURE... THE SEEMINGLY EVER- PRESENT EASTERN NORTH AMERICAN UPPER TROUGH WILL REASSERT ITSELF THROUGH THE FIRST PART OF THE UPCOMING WEEK... KEEPING UP IN NORTHWEST FLOW WITH PREDOMINANTLY COLD TEMPERATURES AND DRY WEATHER. HOWEVER... THE FLOW LOOKS TO FLATTEN OUT WITH A WARMING TREND OVER THE SECOND HALF OF THE WEEK. THE GFS AND ECMWF ARE ALSO SUGGESTING A MORE SUBSTANTIAL SHIFT IN THE PATTERN AS WE MOVE INTO THE FOLLOWING WEEK... WITH BOTH 12Z RUNS SUGGESTING A PROMINENT UPPER RIDGE OVER THE EASTERN CONUS BY THE 8TH AND 9TH OF APRIL... WITH A DEEP TROUGH OVER THE WESTERN CONUS DIGGING INTO FAR NORTHERN MEXICO. IF THAT WORKS OUT IT WOULD MEAN QUITE THE SUBSTANTIAL WARM-UP AS WE MOVE INTO THE START OF NEXT WEEK... WITH PERHAPS SOME INTERESTING WEATHER OVER THE CENTRAL PART OF THE COUNTY ONCE THE TROUGH EJECTS EAST. BUT... THAT/S OBVIOUSLY MANY DAYS AWAY... AND NOT ALL OF THE ENSEMBLE SOLUTIONS ARE IN LINE WITH THAT THINKING... SO WILL BE SOMETHING TO MULL OVER AND KEEP AN EYE ON THROUGH THE UPCOMING WEEK. IN THE MEANTIME... THINGS WILL BE FAIRLY QUIET AND COOL... WITH A FEW CHANCES FOR PCPN OVER THE UPCOMING SEVEN DAYS. PCPN ASSOCIATED WITH THE INITIAL FRONTAL PASSAGE HAS EXITED THE FORECAST AREA... WITH MAINLY PARTLY CLOUDY SKIES DEVELOPING IN ITS WAKE. HOWEVER... THERE IS AN AREA OF STRATUS AND FOG NORTH OF THE MINNESOTA RIVER VALLEY AND ALSO ACROSS THE NORTHWEST CWFA NEAR KAXN. THESE HAVE MIXED OUT SOME DURING THE DAY... BUT LIKELY WILL NOT GO AWAY ENTIRELY BEFORE NIGHT DESCENDS ON THE AREA. THE ARCTIC COLD FRONT WILL DROP ACROSS THE AREA TONIGHT BRINGING THE RETURN OF MUCH BELOW NORMAL TEMPERATURES FOR SEVERAL DAYS. EXPECT TO SEE SOME SNOW SHOWERS/FLURRIES SQUEEZED OUT AS THE FRONT MOVES THROUGH THE AREA... WITH PERHAPS SOME FLURRIES LINGERING OVER THE EAST INTO SUNDAY AS CYCLONIC FLOW AND DECENT BOUNDARY LAYER MOISTURE PERSIST. STRONG NORTHWEST WINDS WILL OCCUR BEHIND THE FRONT... ADDING AND ADDITIONAL NIP TO THE AIR THROUGH SUNDAY BEFORE ARCTIC HIGH PRESSURE BUILDS IN AND WORKS TO KEEP THINGS COLD AND DRY THROUGH WEDNESDAY. THE GFS AND ECMWF ARE IN REMARKABLY GOOD AGREEMENT THROUGH THE FORECAST PERIOD... WITH BOTH BRINGING US INTO RETURN FLOW ON THE BACKSIDE OF THE HIGH BY LATE WEDNESDAY... THEN SWINGING ANOTHER COLD FRONT THROUGH THE AREA ON THURSDAY. THAT FRONT WON/T HAVE NEARLY THE PUNCH AS TONIGHT/S... BUT WILL STILL DELAY THE RETURN OF MUCH WARMER TEMPERATURES. WE WILL ALSO SEE SOME CHANCE FOR LIGHT PCPN WEDNESDAY INTO EARLY THURSDAY AHEAD OF THE FRONT. WENT WITH CHANCES FOR RAIN AND SNOW AT THIS POINT... SINCE IT/S TOUGH TO SAY EXACTLY HOW MUCH WE/LL WARM BEFORE WE COOL DOWN SLIGHTLY AGAIN. CHANCES FOR MORE WIDESPREAD PCPN LOOK TO WORK INTO THE AREA LATE FRIDAY INTO SATURDAY AS WE GET INTO MORE ROBUST RETURN FLOW AND WARM ADVECTION AHEAD OF A SURFACE LOW THAT LOOKS TO LIFT NORTHEAST ACROSS MINNESOTA ON SATURDAY. ALLOWED FOR A TRANSITION FROM SNOW TO RAIN CHANCES WITH THAT SYSTEM... AND A SOMEWHAT EARLIER ARRIVAL THAN THE 12Z GUIDANCE WOULD SUGGEST. HOWEVER... PREVIOUS RUNS HAD A BIT MORE UNCERTAINTY WITH THE TIMING... SO WANTED TO TREND THINGS TOWARD A LATER START WITHOUT ENTIRELY DITCHING EARLIER FORECASTS. LATEST GUIDANCE WOULD ALSO SHIFT ANY CHANCE OF SNOW WELL NORTH ON SATURDAY... BUT KEPT SOME MIXED POTENTIAL OVER THE FAR NORTHERN CWFA TO AT LEAST ALLOW FOR SOME AT THE START OF THE DAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 06Z SUNDAY EVENING) WATCHING SHORTWAVE ACROSS THE DAKOTAS...ALONG WITH SECONDARY COLD FRONT MOVING SOUTH ACROSS SRN CAN. SREF IN PARTICULAR WANTING TO BREAK OUT SOME LIGHT PRECIP NORTH OF I-94 AS THE SHORT WAVE MOVES ACROSS THE AREA THIS EVENING. DEEP MOISTURE LOOKS TO BE LACKING...SO HELD ANY PRECIP MENTION IN TAFS TO A VC. AGAIN...LOCAL HOPWRF HI-RES ENSEMBLE LOOKS TO HAVE A GOOD HANDEL ON THIS FEATURE...SO USED IT TO TIME ANY VC MENTION IN TAFS. AS FOR THE COLD FRONT...UNLIKE THIS MORNINGS...THIS SECOND COLD FRONT WILL BRING WITH IT STRONG COLD AIR ADVECTION AND WITH THAT...A BANK OF POST FRONTAL STRATUS. 925-850 LAYER RH FROM THE NAM/RAP WAS USED TO TIME THESE CIGS INTO TERMINALS LATE TONIGHT. HOPWRF ENSEMBLE SHOWS MVFR CIGS RETURNING AS WELL...THOUGH SEVERAL HOURS EARLIER. GIVEN THE LACK OF MVFR CIGS CURRENTLY BEING OBS ACROSS CANADA...FAVORED THE SLOWER TIMING IN THESE TAFS. GIVEN STEEP LAPSE RATES EXPECTED SUNDAY...SHOULD HAVE NO PROBLEM MAINTAINING BKN-OVC STRATOCU...QUESTION IS HOW LOW. FOR NOW...PLAYED CONDS TO TREND TOWARD VFR BY THE AFTERNOON...BUT WE COULD VERY WELL HOLD CIGS IN THE 020-030 RANGE THROUGH MONDAY NIGHT. OUT IN WRN MN...BR/HZ OBS HAVE BEEN SLOW TO IMPROVE FROM REMNANT FOG THIS MORNING...AND WITH A WEAKNESS IN THE PRESSURE FIELD SEEN OUT THERE...FOLLOWED THE IDEA OF THE HRRR WITH MVFR OR LOWER VSBYS RETURNING FOR AXN/RWF AHEAD OF THE SECONDARY BOUNDARY...THOUGH CONFIDENCE IS LOW IN THIS SCENARIO PLAYING OUT AT RWF/AXN. FINALLY...ON WINDS...DEEP MIXING IS A CERTAINTY TOMORROW...AND CONFIDENCE IS QUITE HIGH IN NW WINDS GUSTING TO BETWEEN 25 AND 30 KTS MUCH OF THE DAY ON SUNDAY ACROSS MN. KMSP...CONFIDENCE PRETTY HIGH IN FORECAST THROUGH FIRST 8 HOURS...BUT DECREASES AFTER THAT AS NEXT UPPER LEVEL AND SFC BOUNDARY APPROACH. HELD BACK ON MVFR CIGS UNTIL 12Z...WHICH IS WHEN COLD AIR ADVECTION ARRIVES IN FORCE...THOUGH MVFR CONDS COULD COME IN EARLIER BASED ON HOPWRF PROBS FOR CIGS LESS THAN 3K FT. FOR NOW...KEPT CIGS ABOVE 017..BUT WOULD NOT RULE OUT CIGS BETWEEN 010 AND 015 SUNDAY MORNING. FOR NOW...SHOW CIGS TRENDING TO VFR...BUT CONFIDENCE NOT VERY HIGH ON THAT. CONFIDENCE IS HIGH HOWEVER IN THE WIND FORECAST AND IF ANYTHING...WOULD SAY THE SPEEDS ARE CONSERVATIVE...THOUGH A 300-320 DIRECTION WILL BE FAVORABLE FOR AIRPORT OPS. /OUTLOOK FOR KMSP/ MON...MVFR CIGS POSSIBLE. WINDS NW 15G25KTS. TUE...VFR. WIND NW 10 KTS. WED...VFR. WIND S 5-10 KTS BCMG 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ AVIATION...MPG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
318 PM CDT FRI MAR 29 2013 .SYNOPSIS... ISSUED AT 318 PM CDT FRI MAR 29 2013 H5 HAND ANALYSIS THIS MORNING IS INDICATING BROAD LOW AMPLITUDE FLOW ACROSS THE LOWER 48...WITH EMBEDDED SHORTWAVES NOTED OVER THE NORTHERN ROCKIES OF IDAHO AND MONTANA. ABUNDANT MID LEVEL INSTABILITY AND MID LEVEL ALTO CU HAS TRACKED INTO WESTERN AND CENTRAL NEBRASKA THIS MORNING...WITH RADAR INDICATING HIGHLY ELEVATED SHOWERS...NONE OF WHICH IS REACHING THE GROUND ATTM. AT THE SURFACE...A LEE SIDE TROUGH HAS BEGUN TO DEEPEN ACROSS THE PANHANDLE AND FAR EASTERN COLORADO OVER THE PAST COUPLE OF HOURS. THIS HAS RESULTED IN INCREASED SRLY WINDS THIS AFTERNOON AND INCREASED LOW LEVEL MOISTURE...WITH DEW POINTS BEGINNING TO REACH INTO THE LOWER 40S AS OF 3 PM CDT. TEMPERATURES AS OF 3 PM CDT RANGED FROM 64 DEGREES AT VALENTINE TO 71 DEGREES AT OGALLALA. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 318 PM CDT FRI MAR 29 2013 MAIN FORECASTING CHALLENGES OVER THE NEXT 24 HOURS ARE THUNDERSTORM POTENTIAL AND ASSOCIATED PRECIPITATION CHANCES TONIGHT...THEN LOW PRECIPITATION CHANCES FOR SATURDAY...IN PARTICULAR SATURDAY AFTERNOON. FOR TONIGHT...AM EXPECTING SOME ISOLATED TSRA INITIATION INVOF OF SURFACE TROUGH AXIS LATER THIS AFTERNOON. BASED ON THE LATEST NAM AND RUC SOLNS...THIS SHOULD BE SOMEWHERE FROM AROUND OGALLALA TO NORTHERN CHERRY COUNTY BY 21Z THIS AFTERNOON. AM EXPECTING ISOLATED CONVECTION TO FIRE INVOF OF THIS FEATURE DURING THE 21Z TO 00Z TIME FRAME LATER THIS AFTERNOON. DECENT MID LEVEL FLOW...WILL TRACK ANY ISOLATED CONVECTION QUICKLY EAST INTO THE CENTRAL AND EASTERN CWFA LATER THIS EVENING AND OVERNIGHT. CONVECTION IS EXPECTED TO BECOME BETTER ORGANIZED IN THE EASTERN CWFA OVERNIGHT AS A NICE LOW LEVEL JET PUSHES NORTH INTO EASTERN NEBR...THE NOSE OF WHICH PUSHES INTO OUR NERN ZONES. FOR PRECIPITATION CHANCES TONIGHT...FAVORED POPS AROUND 20 PERCENT...ALONG AND WEST OF HIGHWAY 83...INCREASING THEM EASTWARD TO AROUND 50 PERCENT IN THE NERN CWA. AS FOR THE THREAT OF SEVERE THUNDERSTORMS TONIGHT...THE LATEST SWODY1 HAS A SEE TEXT ACROSS OUR SWRN ZONES AND CENTRAL SANDHILLS MAINLY FOR EARLY EVENING CONVECTION TIED TO PEAK HEATING. AT THIS JUNCTURE...SOME GUSTY WINDS MAY ACCOMPANY THE STRONGEST STORMS GIVEN THE DRY CONDS BLO 10000 FT AGL AND EXPECTED HIGH BASED TSRAS IN THE WEST. EVEN IN LIGHT OF WET BULB ZEROES OF AROUND 9000 FT MSL...LARGE HAIL THREAT WILL BE MINIMAL AS DEEP LAYER SHEAR IS ONLY AROUND 30 KTS AND FREEZING LEVELS ARE AROUND 5 TO 7 THOUSAND FT AGL. FOR SATURDAY...NORTHWESTERLY WINDS WILL DEVELOP BEHIND EXITING LOW PRESSURE AND MAY BECOME GUSTY DURING THE AFTERNOON HOURS. WITH SURFACE HEATING...MID LEVEL LAPSE RATES WILL STEEPEN SIGNIFICANTLY DURING THE AFTERNOON HOURS...AND WILL CONTINUE MENTION OF ISOLATED SHOWERS. LI`S ARE BARELY NEGATIVE TOMORROW AFTERNOON AND WILL FORGO MENTION OF THUNDER ATTM. HIGHS SATURDAY WILL BE COOLER THAN TDYS READINGS. BASED ON H85 TEMPS AND GOOD MIXING...HIGHS WILL RANGE FROM THE 50S NORTH...TO THE LOWER 60S IN THE SOUTH. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 318 PM CDT FRI MAR 29 2013 SATURDAY NIGHT WILL SEE A DISTURBANCE PUSHING SOUTH AND AN ARCTIC COLD FRONT DIPPING SOUTH ACROSS THE NORTHERN PLAINS. BY SUNDAY AFTERNOON THE COLD FRONT WILL BE PUSHING INTO NRN NEBRASKA. SHOULD SQUEAK OUT ANOTHER NICE DAY WITH HIGHS IN THE 60S FOR MOST OF THE CWA. PORTIONS OF NORTH CENTRAL WILL SEE HIGHS ONLY IN THE 50S AS THE COLD FRONT ARRIVES BEFORE PEAK HEAT. ALSO GOING TO SEE SOME SHOWERS DEVELOP ALONG/AHEAD OF THE FRONT...MAINLY WHERE THERE IS BETTER MOISTURE TO THE EAST. BY SUNDAY NIGHT COLD AIR WILL PUSH ACROSS THE AREA. NOT A GREAT CHANCE FOR PRECIP...BUT COLD AIR ALOFT WILL CREATE SOME STEEP LAPSE RATES. ALSO AS TEMPS FALL A MIX OR CHANGE TO SNOW CAN BE EXPECTED. MONDAY WILL FEEL THE COLD ARCTIC AIR AS HIGHS ONLY WARM INTO THE MID 30S TO MID 40S. PRECIP WILL BE PUSHING SOUTH...SO HIGHS MAY ACTUALLY BE ABLE TO WARM UP A LITTLE MORE THAN FORECAST AS APRIL SUNSHINE ARRIVES FOR THE AFTERNOON. COLD AIR IS SHORT LIVED AS CENTER OF HIGH SHIFTS TO THE EAST FOR TUESDAY...WITH RETURN SOUTHERLY FLOW BY TUESDAY AFTERNOON. NOT A FAST REBOUND ON TUESDAY AS HIGHS ONLY IN THE 40S TO LOW 50S. WEDNESDAY INTO THURSDAY WILL CONTINUE TO SEE A REBOUND OF TEMPS. SURF HIGH CONTINUES TO PUSH TO THE SE WITH MORE WARM AIR TO PUSH NORTHWARD AND THE BACKSIDE OF THE HIGH. 850 MB TEMPS PUSH INTO THE SINGLE DIGITS ABOVE ZERO AND CLOSE TO 10 IN THE WEST WITH GUIDANCE CLOSE TO 60. PRECIP CHANCES DO NOT LOOK GOOD THROUGH THE WEEK...AS GULF MOISTURE REMAINS SHUT OFF AND MODELS CONTINUE A DRY BL. AN UPPER LEVEL DISTURBANCE LATE IN THE WEEK MAY BRING SOME LIGHT PRECIP...BUT WILL HAVE TO BE A TOP DOWN SATURATION AND DO NOT HAVE IN THE FORECAST ATTM. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1250 CDT FRI MAR 29 2013 GENERALLY VRF CONDITIONS THE NEXT 24 HOURS. TROUGH MOVING ACROSS THE AREA THIS EVENING. WEAK INSTABILITY SHOULD BE ENOUGH FOR ISOLD TO SCT THUNDERSTORM DEVELOPMENT. DEVELOPMENT IS EXPECTED ACROSS WESTERN NEBRASKA AROUND 22Z TO 23Z AND PROGRESS EASTWARD. AM EXPECTING IMPACT AT BOTH TERMINALS...KLBF AND KVTN...HOWEVER DURATION WILL NOT BE LONG. COULD SEE A BRIEF REDUCTION TO MVFR VSBY...HOWEVER THE THUNDER WILL BE THE MAIN CONCERN. BY 01Z THE STORMS SHOULD BE EAST OF THE TERMINALS. WINDS TODAY WILL BE SOUTHERLY...BECOMING NORTHWESTERLY OVERNIGHT...BEHIND THE TROUGH. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CLB SHORT TERM...CLB LONG TERM...MASEK AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1244 PM CDT FRI MAR 29 2013 .AVIATION... 18Z TAFS FOR KOMA...KLNK AND KOFK. VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST 04Z THEN ARE EXPECTED TO DETERIORATE AS AN AREA OF SHOWERS DEVELOPS TO THE WEST AND DRIFTS SOUTHEAST AHEAD OF AN APPROCHING COLD FRONT. A FEW ISOLATED THUNDERSTORMS ARE POSSIBLE BUT WILL LEAVE THE MENTION OUT OF THE TAFS FOR NOW WITH ANOTHER MAIN TAF ISSUANCE BETWEEN NOW AND THE TIME ANY DEVELOPMENT WOULD OCCUR. CIGS MAY DROP TO MVFR OR EVEN AS LOW AS IFR IN THE SHOWERS. SFC WINDS WILL TURN TO THE NORTHWEST AROUND 12Z AS THE SFC COLD FRONT PUSHES ACROSS THE SITES. && .PREV DISCUSSION... /ISSUED 340 AM CDT FRI MAR 29 2013/ SHORT TERM...TODAY THROUGH SATURDAY NIGHT. THE MAIN FORECAST CONCERNS IN THIS PERIOD ARE CHANCES FOR SHOWERS/ THUNDERSTORMS AND TEMPERATURES. TEMPERATURES YESTERDAY TOPPED OUT MAINLY IN THE UPPER 50S AND LOWER 60S ACROSS THE FORECAST AREA. HIGHS TODAY SHOULD BE ABOUT 3 TO 5 DEGREES WARMER...BASED ON A SMALL INCREASE IN 850 MB TEMPS. THERE IS SOME CONCERN THAT PCPN COULD DEVELOP LATE THIS AFTERNOON AS LOW LEVEL MOISTURE AND INSTABILITY INCREASE. BUT BASED ON MOST RECENT FORECASTS OF MOST UNSTABLE CAPE FORECASTS FROM RAP MODEL...KEPT THINGS DRY UNTIL THIS EVENING. 850 MB DEWPOINTS WERE IN THE 5 TO 10 DEGREE CELSIUS RANGE LAST EVENING ACROSS THE SOUTHERN PLAINS... MAINLY FROM OKLAHOMA SOUTH. MODEL SHOW MOISTURE INCREASING IN OUR AREA...BUT MAIN AXIS STAYS MAINLY TO OUR WEST IN CENTRAL NEBRASKA THROUGH 00Z THIS EVENING. THIS 850 MB MOISTURE SHOULD SPREAD OVER OUR AREA TONIGHT AND THEN OUT OF THE AREA SATURDAY. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND SATURDAY MORNING. SOME OF THE MODEL QPFS LOOK A LITTLE HIGH...BUT CERTAINLY AMOUNTS BETWEEN A TENTH AND A QUARTER OF AN INCH SEEM REASONABLE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. COMBINATION OF CLOUD COVER AND WIND SHOULD HELP KEEP LOWS TONIGHT IN THE 40S MOST SPOTS. ON SATURDAY...A WIND SHIFT WILL MOVE ACROSS THE AREA...BUT 850 MB TEMPERATURES DO NOT CHANGE MUCH AND MIXING SHOULD BE GOOD. STAYED FAIRLY CLOSE TO PREVIOUS FORECAST FOR HIGHS SATURDAY...RANGING FROM UPPER 50S NORTH TO MID OR UPPER 60S FAR SOUTH. IF CLOUDS AND PCPN CLEAR OUT FASTER THAN CURRENTLY EXPECTED...HIGHS COULD BE A LITTLE WARMER NORTHERN AND CENTRAL ZONES. SATURDAY NIGHT WE ARE BETWEEN SYSTEMS AND FOR NOW KEPT THINGS DRY. SOME SHOWERS COULD DEVELOP TO OUR WEST IN THE AFTERNOON BUT FOR NOW EXPECTED THESE TO DISSIPATE SATURDAY EVENING BEFORE REACHING SOUTHEAST NEBRASKA. LOWS WILL DROP INTO THE 30S SATURDAY NIGHT. MILLER LONG TERM...SUNDAY THROUGH THURSDAY. MAIN CONCERNS IN THIS PERIOD ARE TEMPERATURES SUNDAY AND PCPN CHANCES FOR SUNDAY INTO SUNDAY NIGHT. A STRONG COLD FRONT WILL BE PUSHING INTO OUR NORTHERN ZONES SUNDAY AFTERNOON...SO JUST HOW WARM IT WILL GET IS PROBLEMATIC. AIRMASS WILL BE STARTING OUT QUITE MILD...BUT TEMPERATURES SHOULD BE FALLING IN THE AFTERNOON ACROSS NORTHEAST NEBRASKA AS WINDS SHIFT TO THE NORTH. WENT WITH HIGHS CLOSE TO NOON NORTH IN THE 50S...BUT IN THE 60S MID OR LATE AFTERNOON SOUTH. BUT AGAIN THIS WILL DEPEND ON FRONTAL TIMING. AREAS ALONG THE KANSAS BORDER COULD APPROACH 70...BUT DID NOT WANT TO GET TOO OPTIMISTIC AT THIS POINT. FAIRLY DECENT FORCING IS EXPECTED ALONG AND BEHIND THE FRONT...SO KEPT POPS 20 TO 30 PERCENT MOST AREAS SUNDAY AFTERNOON. PCPN TYPE WILL BE AN ISSUE AS THE COLD AIR POURS IN FOR SUNDAY NIGHT...WITH RAIN CHANGING TO SNOW. TRIED TO ADD SOME DETAIL TO PCPN TYPE SUNDAY NIGHT BUT THIS WILL BE REFINED AS WE GET CLOSER. DID NOT MENTION ANY SNOW ACCUMULATION AT THIS POINT...BUT THAT WILL NEED TO BE MONITORED CLOSELY. HIGHS MONDAY SHOULD ONLY REACH THE 30S...BUT THEN LOOK FOR MODERATING TEMPERATURES THROUGH THURSDAY AS MILDER AIR MOVES IN FROM THE SOUTH AND WEST. MILLER && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
628 AM CDT FRI MAR 29 2013 .AVIATION... 12Z TAFS FOR KOMA...KLNK...KOFK. VFR CONDITIONS EXPECTED THROUGH 03Z THEN CONDITIONS EXPECTED TO DETERIORATE FOR THE REMAINDER OF THE PERIOD AS APPROACHING COLD FRONT BRINGS SCATTERED SHOWERS AND THUNDERSTORMS INTO THE AREA WITH MVFR CIGS AND VSBYS. && .PREV DISCUSSION... /ISSUED 340 AM CDT FRI MAR 29 2013/ SHORT TERM...TODAY THROUGH SATURDAY NIGHT. THE MAIN FORECAST CONCERNS IN THIS PERIOD ARE CHANCES FOR SHOWERS/ THUNDERSTORMS AND TEMPERATURES. TEMPERATURES YESTERDAY TOPPED OUT MAINLY IN THE UPPER 50S AND LOWER 60S ACROSS THE FORECAST AREA. HIGHS TODAY SHOULD BE ABOUT 3 TO 5 DEGREES WARMER...BASED ON A SMALL INCREASE IN 850 MB TEMPS. THERE IS SOME CONCERN THAT PCPN COULD DEVELOP LATE THIS AFTERNOON AS LOW LEVEL MOISTURE AND INSTABILITY INCREASE. BUT BASED ON MOST RECENT FORECASTS OF MOST UNSTABLE CAPE FORECASTS FROM RAP MODEL...KEPT THINGS DRY UNTIL THIS EVENING. 850 MB DEWPOINTS WERE IN THE 5 TO 10 DEGREE CELSIUS RANGE LAST EVENING ACROSS THE SOUTHERN PLAINS... MAINLY FROM OKLAHOMA SOUTH. MODEL SHOW MOISTURE INCREASING IN OUR AREA...BUT MAIN AXIS STAYS MAINLY TO OUR WEST IN CENTRAL NEBRASKA THROUGH 00Z THIS EVENING. THIS 850 MB MOISTURE SHOULD SPREAD OVER OUR AREA TONIGHT AND THEN OUT OF THE AREA SATURDAY. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND SATURDAY MORNING. SOME OF THE MODEL QPFS LOOK A LITTLE HIGH...BUT CERTAINLY AMOUNTS BETWEEN A TENTH AND A QUARTER OF AN INCH SEEM REASONABLE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. COMBINATION OF CLOUD COVER AND WIND SHOULD HELP KEEP LOWS TONIGHT IN THE 40S MOST SPOTS. ON SATURDAY...A WIND SHIFT WILL MOVE ACROSS THE AREA...BUT 850 MB TEMPERATURES DO NOT CHANGE MUCH AND MIXING SHOULD BE GOOD. STAYED FAIRLY CLOSE TO PREVIOUS FORECAST FOR HIGHS SATURDAY...RANGING FROM UPPER 50S NORTH TO MID OR UPPER 60S FAR SOUTH. IF CLOUDS AND PCPN CLEAR OUT FASTER THAN CURRENTLY EXPECTED...HIGHS COULD BE A LITTLE WARMER NORTHERN AND CENTRAL ZONES. SATURDAY NIGHT WE ARE BETWEEN SYSTEMS AND FOR NOW KEPT THINGS DRY. SOME SHOWERS COULD DEVELOP TO OUR WEST IN THE AFTERNOON BUT FOR NOW EXPECTED THESE TO DISSIPATE SATURDAY EVENING BEFORE REACHING SOUTHEAST NEBRASKA. LOWS WILL DROP INTO THE 30S SATURDAY NIGHT. MILLER LONG TERM...SUNDAY THROUGH THURSDAY. MAIN CONCERNS IN THIS PERIOD ARE TEMPERATURES SUNDAY AND PCPN CHANCES FOR SUNDAY INTO SUNDAY NIGHT. A STRONG COLD FRONT WILL BE PUSHING INTO OUR NORTHERN ZONES SUNDAY AFTERNOON...SO JUST HOW WARM IT WILL GET IS PROBLEMATIC. AIRMASS WILL BE STARTING OUT QUITE MILD...BUT TEMPERATURES SHOULD BE FALLING IN THE AFTERNOON ACROSS NORTHEAST NEBRASKA AS WINDS SHIFT TO THE NORTH. WENT WITH HIGHS CLOSE TO NOON NORTH IN THE 50S...BUT IN THE 60S MID OR LATE AFTERNOON SOUTH. BUT AGAIN THIS WILL DEPEND ON FRONTAL TIMING. AREAS ALONG THE KANSAS BORDER COULD APPROACH 70...BUT DID NOT WANT TO GET TOO OPTIMISTIC AT THIS POINT. FAIRLY DECENT FORCING IS EXPECTED ALONG AND BEHIND THE FRONT...SO KEPT POPS 20 TO 30 PERCENT MOST AREAS SUNDAY AFTERNOON. PCPN TYPE WILL BE AN ISSUE AS THE COLD AIR POURS IN FOR SUNDAY NIGHT...WITH RAIN CHANGING TO SNOW. TRIED TO ADD SOME DETAIL TO PCPN TYPE SUNDAY NIGHT BUT THIS WILL BE REFINED AS WE GET CLOSER. DID NOT MENTION ANY SNOW ACCUMULATION AT THIS POINT...BUT THAT WILL NEED TO BE MONITORED CLOSELY. HIGHS MONDAY SHOULD ONLY REACH THE 30S...BUT THEN LOOK FOR MODERATING TEMPERATURES THROUGH THURSDAY AS MILDER AIR MOVES IN FROM THE SOUTH AND WEST. MILLER && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ FOBERT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
340 AM CDT FRI MAR 29 2013 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT. THE MAIN FORECAST CONCERNS IN THIS PERIOD ARE CHANCES FOR SHOWERS/ THUNDERSTORMS AND TEMPERATURES. TEMPERATURES YESTERDAY TOPPED OUT MAINLY IN THE UPPER 50S AND LOWER 60S ACROSS THE FORECAST AREA. HIGHS TODAY SHOULD BE ABOUT 3 TO 5 DEGREES WARMER...BASED ON A SMALL INCREASE IN 850 MB TEMPS. THERE IS SOME CONCERN THAT PCPN COULD DEVELOP LATE THIS AFTERNOON AS LOW LEVEL MOISTURE AND INSTABILITY INCREASE. BUT BASED ON MOST RECENT FORECASTS OF MOST UNSTABLE CAPE FORECASTS FROM RAP MODEL...KEPT THINGS DRY UNTIL THIS EVENING. 850 MB DEWPOINTS WERE IN THE 5 TO 10 DEGREE CELSIUS RANGE LAST EVENING ACROSS THE SOUTHERN PLAINS... MAINLY FROM OKLAHOMA SOUTH. MODEL SHOW MOISTURE INCREASING IN OUR AREA...BUT MAIN AXIS STAYS MAINLY TO OUR WEST IN CENTRAL NEBRASKA THROUGH 00Z THIS EVENING. THIS 850 MB MOISTURE SHOULD SPREAD OVER OUR AREA TONIGHT AND THEN OUT OF THE AREA SATURDAY. KEPT FAIRLY HIGH POPS GOING FOR TONIGHT AND SATURDAY MORNING. SOME OF THE MODEL QPFS LOOK A LITTLE HIGH...BUT CERTAINLY AMOUNTS BETWEEN A TENTH AND A QUARTER OF AN INCH SEEM REASONABLE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. COMBINATION OF CLOUD COVER AND WIND SHOULD HELP KEEP LOWS TONIGHT IN THE 40S MOST SPOTS. ON SATURDAY...A WIND SHIFT WILL MOVE ACROSS THE AREA...BUT 850 MB TEMPERATURES DO NOT CHANGE MUCH AND MIXING SHOULD BE GOOD. STAYED FAIRLY CLOSE TO PREVIOUS FORECAST FOR HIGHS SATURDAY...RANGING FROM UPPER 50S NORTH TO MID OR UPPER 60S FAR SOUTH. IF CLOUDS AND PCPN CLEAR OUT FASTER THAN CURRENTLY EXPECTED...HIGHS COULD BE A LITTLE WARMER NORTHERN AND CENTRAL ZONES. SATURDAY NIGHT WE ARE BETWEEN SYSTEMS AND FOR NOW KEPT THINGS DRY. SOME SHOWERS COULD DEVELOP TO OUR WEST IN THE AFTERNOON BUT FOR NOW EXPECTED THESE TO DISSIPATE SATURDAY EVENING BEFORE REACHING SOUTHEAST NEBRASKA. LOWS WILL DROP INTO THE 30S SATURDAY NIGHT. MILLER .LONG TERM...SUNDAY THROUGH THURSDAY. MAIN CONCERNS IN THIS PERIOD ARE TEMPERATURES SUNDAY AND PCPN CHANCES FOR SUNDAY INTO SUNDAY NIGHT. A STRONG COLD FRONT WILL BE PUSHING INTO OUR NORTHERN ZONES SUNDAY AFTERNOON...SO JUST HOW WARM IT WILL GET IS PROBLEMATIC. AIRMASS WILL BE STARTING OUT QUITE MILD...BUT TEMPERATURES SHOULD BE FALLING IN THE AFTERNOON ACROSS NORTHEAST NEBRASKA AS WINDS SHIFT TO THE NORTH. WENT WITH HIGHS CLOSE TO NOON NORTH IN THE 50S...BUT IN THE 60S MID OR LATE AFTERNOON SOUTH. BUT AGAIN THIS WILL DEPEND ON FRONTAL TIMING. AREAS ALONG THE KANSAS BORDER COULD APPROACH 70...BUT DID NOT WANT TO GET TOO OPTIMISTIC AT THIS POINT. FAIRLY DECENT FORCING IS EXPECTED ALONG AND BEHIND THE FRONT...SO KEPT POPS 20 TO 30 PERCENT MOST AREAS SUNDAY AFTERNOON. PCPN TYPE WILL BE AN ISSUE AS THE COLD AIR POURS IN FOR SUNDAY NIGHT...WITH RAIN CHANGING TO SNOW. TRIED TO ADD SOME DETAIL TO PCPN TYPE SUNDAY NIGHT BUT THIS WILL BE REFINED AS WE GET CLOSER. DID NOT MENTION ANY SNOW ACCUMULATION AT THIS POINT...BUT THAT WILL NEED TO BE MONITORED CLOSELY. HIGHS MONDAY SHOULD ONLY REACH THE 30S...BUT THEN LOOK FOR MODERATING TEMPERATURES THROUGH THURSDAY AS MILDER AIR MOVES IN FROM THE SOUTH AND WEST. MILLER && .AVIATION... 06Z TAFS FOR KOMA...KLNK...KOFK. LIGHT FOG REMAINS A SMALL RISK AT TAF SITES LATE TONIGHT...BUT DWPTS HAVE REMAINED LOW ENOUGH SO THAT CHANCES APPEARED TOO SMALL TO INCLUDE IN 06Z TAFS. A DISTURBANCE TRACKING ACROSS THE DAKOTAS LATE FRIDAY WILL BRING INCREASING MID CLOUDS AND POSSIBLY MVFR CIGS TO TAF SITES FRIDAY NIGHT...ALONG WITH SCT SHOWERS/ THUNDERSTORMS. IT APPEARED MVFR OR LOWER CIGS...IF THEY OCCURRED... WOULD HOLD OFF UNTIL AFTER 30/06Z. SHOWERS COULD APPROACH KOFK VICINITY BEFORE 30/06Z AND A PROB30 GROUP WAS INCLUDED AT THAT SITE LAST 3 HRS OF TAF PERIOD. APPEARS SHOWER CHANCES AT KOMA AND KLNK WOULD BE MAINLY AFTER 30/06Z. CHERMOK && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
704 PM EDT FRI MAR 29 2013 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE COLD FRONT WILL SHIFT SOUTHEASTWARD ACROSS THE NORTH COUNTRY DURING THE LATE AFTERNOON AND EVENING HOURS...BRINGING SCATTERED RAIN SHOWERS AND HIGHER ELEVATION SNOW SHOWERS. PRECIPITATION WILL END DURING THE PRE-DAWN HOURS SATURDAY. SURFACE HIGH PRESSURE BUILDS INTO THE NORTH COUNTRY DURING SATURDAY BRINGING MOSTLY SUNNY SKIES AND VALLEY TEMPERATURES IN THE UPPER 40S TO LOWER 50S. CLOUDS WILL INCREASE DURING SUNDAY...WITH THE NEXT FRONTAL SYSTEM BRINGING RAIN LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... AS OF 651 PM EDT FRIDAY...RECENT COMPOSITE RADAR IMAGERY SHOWS AN OVERALL DECREASE IN COVERAGE OF INSTABILITY RAIN/MTN SNOW SHOWERS ACROSS THE NORTH COUNTRY LATE THIS AFTERNOON. WATER VAPOR IMAGERY AND RAP OBJECTIVE ANALYSES SUGGEST THE THE WEAK SHORTWAVE DISTURBANCE IN NORTHWEST FLOW ALOFT AND ITS ASSOCIATED COLD POCKET OF AIR IN LOW/MID-LEVELS IS CURRENTLY PUSHING INTO SOUTHERN NEW ENGLAND...WITH DRIER SUBSIDENT FLOW ENTERING INTO THE SAINT LAWRENCE VALLEY. COMBINATION OF LOSS OF DAYTIME HEATING AND THE CONTINUED SOUTHEASTWARD MOVEMENT OF THE SHORTWAVE TROUGH SHOULD CONTINUE TO RESULT IN A DECREASE IN RAIN/SNOW SHOWER COVERAGE AND SKY COVER OVER THE NEXT FEW HOURS. BY LATE EVENING...WOULD EXPECT THAT ANY SHOWER ACTIVITY WOULD HAVE ENDED. MAINLY DRY FORECAST WITH SKIES CONTINUING TO CLEAR OUT DURING THE OVERNIGHT. THERE COULD BE A FEW SHELTERED VALLEYS AND HOLLOWS THAT MAY SEE SOME GROUND FOG/MIST BUT WILL LEAVE OUT OF THE FORECAST FOR NOW DUE TO THE LIMITED EXTENT OF ANY MIST/FOG. NO CHANGES TO LOW TEMPERATURES FOR THIS EVENING...GENERALLY IN THE 20S TO LOWER 30S. PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 337 PM EDT FOLLOWS... MARGINALLY UNSTABLE AIR MASS IN PLACE LATE THIS AFTERNOON (RAP- BASED LAPS ANALYSIS SHOWS SBCAPE VALUES AROUND 100 J/KG AT 19Z) WITH TEMPS IN THE UPR 40S IN THE VALLEYS. WEAK UPR TROUGH AND ASSOCIATED SFC COLD FRONT ACROSS THE ST. LAWRENCE VALLEY WILL TRANSLATE STEADILY SEWD ACROSS THE NORTH COUNTRY THIS EVENING...AND ASSOCIATED WEAK SYNOPTIC ASCENT AND INSTABILITY WILL MAINTAIN SCATTERED CONVECTIVE SHOWERS ALONG AND IN ADVANCE OF THE FRONT THROUGH 03Z. THEREAFTER...CLEARING IS RATHER SHARP BEHIND THE SHORTWAVE TROUGH...AND PRECIPITATION SHOULD GENERALLY END. MAY SEE A FEW LINGERING SNOW SHOWERS THRU 06-09Z ACROSS THE NRN MTNS WITH 1-2 ACCUMULATION ACROSS THE SUMMITS...BUT SKIES WILL GRADUALLY CLEAR IN VALLEY LOCATIONS. NW WINDS 5-10 MPH OVERNIGHT SHOULD PRECLUDE MUCH IN THE WAY OF FOG...BUT CAN/T COMPLETELY RULE OUT A BIT OF GROUND FOG IN THE SHELTERED VALLEYS DURING THE PRE- DAWN HOURS. STAYED SLIGHTLY ABOVE GUIDANCE FOR OVERNIGHT LOWS...MAINLY IN THE LOW 30S ACROSS THE CHAMPLAIN VALLEY AND UPR 20S ELSEWHERE. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 337 PM EDT FRIDAY...MUCH DRIER AIR MASS IN PLACE SATURDAY WITH SURFACE RIDGE AXIS MOVING IN AND CRESTING OVER THE NORTH COUNTRY LATE SATURDAY AFTN/EVE. LOOKING AT MOSTLY CLEAR SKIES AND LIGHT NWLY WINDS. HAVE RAISED HIGH TEMPS 5 DEG FROM MAV/MET BLEND BASED ON RECENT TRENDS...YIELDING A HIGH AROUND 50F IN BURLINGTON. OVERALL...A PLEASANT SATURDAY EXPECTED. CLEAR SKIES PERSIST MOST OF SATURDAY NIGHT WITH GOOD RADIATIONAL COOLING. LIGHT AND VARIABLE WINDS BECOME LIGHT S-SW ACROSS ST. LAWRENCE COUNTY AND INTO THE CHAMPLAIN VALLEY LATE AS RIDGE AXIS SLIDES TO THE MAINE COAST. LOWS AROUND 30F IN THE CHAMPLAIN/ST. LAWRENCE VALLEYS...BUT WILL LOCALLY DROP TO AROUND 20F IN THE MORE SHELTERED LOCATIONS OF THE ADIRONDACKS AND NE KINGDOM OF VERMONT GIVEN GOOD RADIATIVE COOLING SETUP IN THOSE LOCATIONS. A BREEZY DAY AND MILD DAY IS EXPECTED SUNDAY AS P-GRADIENT INCREASES. GRADIENT FLOW INCREASES FROM THE SOUTH AS OCCLUDED FRONT REACHES WRN NY/WRN PA BY 18Z SUNDAY. LOOKING AT 15-25 MPH WITH GUSTS TO 30 MPH EXPECTED. INCREASING HIGH CLOUDS DURING THE MORNING...THEN INTRODUCED INCREASING CHANCES FOR RAIN FROM WEST TO EAST DURING THE AFTN AND EVENING HOURS CONSISTENT WITH MOST OF THE MODEL GUIDANCE (12Z ECMWF IS A BIT SLOWER). WENT A COULD DEGREES ABOVE MOS CONSENSUS FOR HIGH TEMPS (MAINLY IN THE MID 50S IN THE VALLEYS). OCCLUDED FRONT SWINGS THRU 00-06Z MONDAY AND HAVE A PERIOD OF 80-100 POPS WITH SYSTEM BRINGING 0.2-0.4" RAINFALL AMTS MOST SECTIONS. SHOULD SEE ENOUGH COOLING ACROSS THE NRN ADIRONDACKS FOR A SWITCH TO SNOW ACROSS THE HIGHER TERRAIN LATE SUNDAY NIGHT WITH LIGHT SNOW ACCUMULATION POSSIBLE. LOW TEMPS WILL GENERALLY BE IN THE 30S SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 337 PM EDT FRIDAY...OCCLUDED FRONT FROM THE ABOVE MENTIONED SYSTEM SHIFTS EAST OFF THE ATLANTIC COAST MONDAY LEAVING THE CWA IN A SEMI-DRY SLOT MONDAY MORNING. PRECIPITATION WILL FILL BACK IN ACROSS THE REGION BY MID-DAY THOUGH AS SURFACE COLD FRONT MOVES IN ASSOCIATED WITH PARENT LOW MOVING THROUGH SOUTHERN ONTARIO/QUEBEC. BOUNDARY LAYER PROFILES CONTINUE TO SHOW MAIN PTYPE WILL BE RAIN THROUGH MONDAY...BUT TRANSITIONS TO SNOW SHOWERS AS THE FRONT PUSHES THROUGH MONDAY NIGHT. CHANCES FOR SNOW/RAIN SHOWERS CONTINUE TUESDAY AND WEDNESDAY AS WELL AS UPPER LOW IS SLOW TO SHIFT EAST ACROSS QUEBEC AND A SERIES OF SHORTWAVES ROTATE AROUND THE UPPER FLOW. WITH THE COLD CORE UPPER LOW OVER THE REGION AND STRONG COLD AIR ADVECTION AT THE SURFACE...HIGH TEMPS TUESDAY/WEDNESDAY WILL BE WELL BELOW NORMAL IN THE 30S. LOOKS LIKE A FAIRLY COLD NIGHT TOO FOR TUESDAY NIGHT WITH 925-850MB TEMPS IN THE TEENS BELOW ZERO SUPPORTING LOWS MAINLY IN THE TEENS AND DOWN INTO THE SINGLE NUMBERS IN THE COLDER HOLLOWS OF THE DACKS (IE KSLK). PRECIP CHANCES DECREASE GOING INTO WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS EAST FROM THE GREAT LAKES AND ANOTHER BELOW NORMAL NIGHT IS EXPECTED WITH LOWS IN THE TEENS TO LOWER 20S. UPPER RIDGE CRESTS OVER THE NORTH COUNTRY THURSDAY WITH A NICE SPRING DAY LIKELY WITH SUNNY SKIES AND TEMPS WARMING INTO THE 40S. RIDGE BREAKS DOWN THOUGH GOING INTO THURSDAY NIGHT AND FRIDAY TURNING INTO FAIRLY ZONAL FLOW. NO REAL SYSTEMS ON THE OUTLOOK THROUGH THIS PERIOD BUT WITH WESTERLY FLOW ALOFT WE`LL LIKELY SEE A MIX OF SUN AND CLOUDS AND TEMPS RUNNING NEAR NORMAL WITH HIGHS IN THE 40S AND LOWS IN THE 20S TO LOW 30S. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... THROUGH 00Z SUNDAY...ANY LINGERING LIGHT SHOWERS/SPRINKLES ENDING THIS EVENING AS BKN/OVC VFR CIGS TREND TOWARD SKC AFTER 04-08Z AS HIGH PRESSURE BUILDS INTO THE REGION. ONLY EXCEPTION AT KSLK TERMINAL WHERE SOME PESKY MVFR CIGS AROUND FL025 WILL PERSIST THROUGH 03-05Z. WINDS GENERALLY LIGHT WEST TO NORTHWESTERLY AT 5 KTS OR LESS. WE COULD ALSO SEE SOME PATCHY BR SFC VISIBILITIES LATER TONIGHT AS LOWER LEVELS NEAR SATURATION...BUT FEEL ENOUGH MIXING IN THE LOWER LEVELS TO PRECLUDE MENTION AT ANY DISCRETE TERMINAL AT THIS TIME. AFTER 14Z SATURDAY...CLEAR SKIES AND LIGHT WEST TO NORTHWESTERLY WINDS OF 5-10 KTS ARE EXPECTED AS AFOREMENTIONED HIGH PRESSURE BUILDS INTO THE REGION. OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY... 00Z SUNDAY THROUGH 18Z SUNDAY...VFR CONDITIONS UNDER HIGH PRESSURE. 18Z SUNDAY THROUGH 12Z WEDNESDAY...FRONTAL SYSTEM MOVING THROUGH SOUTHERN ONTARIO/QUEBEC WILL BRING LOWERING CEILINGS AND MVFR CONDITIONS IN SCATTERED RAIN/SNOW SHOWERS. 12Z WEDNESDAY THROUGH 00Z THURSDAY...MVFR TRENDING TO VFR AS HIGH PRESSURE BUILDS INTO THE REGION. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS/LOCONTO SHORT TERM...BANACOS LONG TERM...LAHIFF AVIATION...JMG/LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
651 PM EDT FRI MAR 29 2013 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE COLD FRONT WILL SHIFT SOUTHEASTWARD ACROSS THE NORTH COUNTRY DURING THE LATE AFTERNOON AND EVENING HOURS...BRINGING SCATTERED RAIN SHOWERS AND HIGHER ELEVATION SNOW SHOWERS. PRECIPITATION WILL END DURING THE PRE-DAWN HOURS SATURDAY. SURFACE HIGH PRESSURE BUILDS INTO THE NORTH COUNTRY DURING SATURDAY BRINGING MOSTLY SUNNY SKIES AND VALLEY TEMPERATURES IN THE UPPER 40S TO LOWER 50S. CLOUDS WILL INCREASE DURING SUNDAY...WITH THE NEXT FRONTAL SYSTEM BRINGING RAIN LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... AS OF 651 PM EDT FRIDAY...RECENT COMPOSITE RADAR IMAGERY SHOWS AN OVERALL DECREASE IN COVERAGE OF INSTABILITY RAIN/MTN SNOW SHOWERS ACROSS THE NORTH COUNTRY LATE THIS AFTERNOON. WATER VAPOR IMAGERY AND RAP OBJECTIVE ANALYSES SUGGEST THE THE WEAK SHORTWAVE DISTURBANCE IN NORTHWEST FLOW ALOFT AND ITS ASSOCIATED COLD POCKET OF AIR IN LOW/MID-LEVELS IS CURRENTLY PUSHING INTO SOUTHERN NEW ENGLAND...WITH DRIER SUBSIDENT FLOW ENTERING INTO THE SAINT LAWRENCE VALLEY. COMBINATION OF LOSS OF DAYTIME HEATING AND THE CONTINUED SOUTHEASTWARD MOVEMENT OF THE SHORTWAVE TROUGH SHOULD CONTINUE TO RESULT IN A DECREASE IN RAIN/SNOW SHOWER COVERAGE AND SKY COVER OVER THE NEXT FEW HOURS. BY LATE EVENING...WOULD EXPECT THAT ANY SHOWER ACTIVITY WOULD HAVE ENDED. MAINLY DRY FORECAST WITH SKIES CONTINUING TO CLEAR OUT DURING THE OVERNIGHT. THERE COULD BE A FEW SHELTERED VALLEYS AND HOLLOWS THAT MAY SEE SOME GROUND FOG/MIST BUT WILL LEAVE OUT OF THE FORECAST FOR NOW DUE TO THE LIMITED EXTENT OF ANY MIST/FOG. NO CHANGES TO LOW TEMPERATURES FOR THIS EVENING...GENERALLY IN THE 20S TO LOWER 30S. PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 337 PM EDT FOLLOWS... MARGINALLY UNSTABLE AIR MASS IN PLACE LATE THIS AFTERNOON (RAP- BASED LAPS ANALYSIS SHOWS SBCAPE VALUES AROUND 100 J/KG AT 19Z) WITH TEMPS IN THE UPR 40S IN THE VALLEYS. WEAK UPR TROUGH AND ASSOCIATED SFC COLD FRONT ACROSS THE ST. LAWRENCE VALLEY WILL TRANSLATE STEADILY SEWD ACROSS THE NORTH COUNTRY THIS EVENING...AND ASSOCIATED WEAK SYNOPTIC ASCENT AND INSTABILITY WILL MAINTAIN SCATTERED CONVECTIVE SHOWERS ALONG AND IN ADVANCE OF THE FRONT THROUGH 03Z. THEREAFTER...CLEARING IS RATHER SHARP BEHIND THE SHORTWAVE TROUGH...AND PRECIPITATION SHOULD GENERALLY END. MAY SEE A FEW LINGERING SNOW SHOWERS THRU 06-09Z ACROSS THE NRN MTNS WITH 1-2 ACCUMULATION ACROSS THE SUMMITS...BUT SKIES WILL GRADUALLY CLEAR IN VALLEY LOCATIONS. NW WINDS 5-10 MPH OVERNIGHT SHOULD PRECLUDE MUCH IN THE WAY OF FOG...BUT CAN/T COMPLETELY RULE OUT A BIT OF GROUND FOG IN THE SHELTERED VALLEYS DURING THE PRE- DAWN HOURS. STAYED SLIGHTLY ABOVE GUIDANCE FOR OVERNIGHT LOWS...MAINLY IN THE LOW 30S ACROSS THE CHAMPLAIN VALLEY AND UPR 20S ELSEWHERE. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 337 PM EDT FRIDAY...MUCH DRIER AIR MASS IN PLACE SATURDAY WITH SURFACE RIDGE AXIS MOVING IN AND CRESTING OVER THE NORTH COUNTRY LATE SATURDAY AFTN/EVE. LOOKING AT MOSTLY CLEAR SKIES AND LIGHT NWLY WINDS. HAVE RAISED HIGH TEMPS 5 DEG FROM MAV/MET BLEND BASED ON RECENT TRENDS...YIELDING A HIGH AROUND 50F IN BURLINGTON. OVERALL...A PLEASANT SATURDAY EXPECTED. CLEAR SKIES PERSIST MOST OF SATURDAY NIGHT WITH GOOD RADIATIONAL COOLING. LIGHT AND VARIABLE WINDS BECOME LIGHT S-SW ACROSS ST. LAWRENCE COUNTY AND INTO THE CHAMPLAIN VALLEY LATE AS RIDGE AXIS SLIDES TO THE MAINE COAST. LOWS AROUND 30F IN THE CHAMPLAIN/ST. LAWRENCE VALLEYS...BUT WILL LOCALLY DROP TO AROUND 20F IN THE MORE SHELTERED LOCATIONS OF THE ADIRONDACKS AND NE KINGDOM OF VERMONT GIVEN GOOD RADIATIVE COOLING SETUP IN THOSE LOCATIONS. A BREEZY DAY AND MILD DAY IS EXPECTED SUNDAY AS P-GRADIENT INCREASES. GRADIENT FLOW INCREASES FROM THE SOUTH AS OCCLUDED FRONT REACHES WRN NY/WRN PA BY 18Z SUNDAY. LOOKING AT 15-25 MPH WITH GUSTS TO 30 MPH EXPECTED. INCREASING HIGH CLOUDS DURING THE MORNING...THEN INTRODUCED INCREASING CHANCES FOR RAIN FROM WEST TO EAST DURING THE AFTN AND EVENING HOURS CONSISTENT WITH MOST OF THE MODEL GUIDANCE (12Z ECMWF IS A BIT SLOWER). WENT A COULD DEGREES ABOVE MOS CONSENSUS FOR HIGH TEMPS (MAINLY IN THE MID 50S IN THE VALLEYS). OCCLUDED FRONT SWINGS THRU 00-06Z MONDAY AND HAVE A PERIOD OF 80-100 POPS WITH SYSTEM BRINGING 0.2-0.4" RAINFALL AMTS MOST SECTIONS. SHOULD SEE ENOUGH COOLING ACROSS THE NRN ADIRONDACKS FOR A SWITCH TO SNOW ACROSS THE HIGHER TERRAIN LATE SUNDAY NIGHT WITH LIGHT SNOW ACCUMULATION POSSIBLE. LOW TEMPS WILL GENERALLY BE IN THE 30S SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 337 PM EDT FRIDAY...OCCLUDED FRONT FROM THE ABOVE MENTIONED SYSTEM SHIFTS EAST OFF THE ATLANTIC COAST MONDAY LEAVING THE CWA IN A SEMI-DRY SLOT MONDAY MORNING. PRECIPITATION WILL FILL BACK IN ACROSS THE REGION BY MID-DAY THOUGH AS SURFACE COLD FRONT MOVES IN ASSOCIATED WITH PARENT LOW MOVING THROUGH SOUTHERN ONTARIO/QUEBEC. BOUNDARY LAYER PROFILES CONTINUE TO SHOW MAIN PTYPE WILL BE RAIN THROUGH MONDAY...BUT TRANSITIONS TO SNOW SHOWERS AS THE FRONT PUSHES THROUGH MONDAY NIGHT. CHANCES FOR SNOW/RAIN SHOWERS CONTINUE TUESDAY AND WEDNESDAY AS WELL AS UPPER LOW IS SLOW TO SHIFT EAST ACROSS QUEBEC AND A SERIES OF SHORTWAVES ROTATE AROUND THE UPPER FLOW. WITH THE COLD CORE UPPER LOW OVER THE REGION AND STRONG COLD AIR ADVECTION AT THE SURFACE...HIGH TEMPS TUESDAY/WEDNESDAY WILL BE WELL BELOW NORMAL IN THE 30S. LOOKS LIKE A FAIRLY COLD NIGHT TOO FOR TUESDAY NIGHT WITH 925-850MB TEMPS IN THE TEENS BELOW ZERO SUPPORTING LOWS MAINLY IN THE TEENS AND DOWN INTO THE SINGLE NUMBERS IN THE COLDER HOLLOWS OF THE DACKS (IE KSLK). PRECIP CHANCES DECREASE GOING INTO WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS EAST FROM THE GREAT LAKES AND ANOTHER BELOW NORMAL NIGHT IS EXPECTED WITH LOWS IN THE TEENS TO LOWER 20S. UPPER RIDGE CRESTS OVER THE NORTH COUNTRY THURSDAY WITH A NICE SPRING DAY LIKELY WITH SUNNY SKIES AND TEMPS WARMING INTO THE 40S. RIDGE BREAKS DOWN THOUGH GOING INTO THURSDAY NIGHT AND FRIDAY TURNING INTO FAIRLY ZONAL FLOW. NO REAL SYSTEMS ON THE OUTLOOK THROUGH THIS PERIOD BUT WITH WESTERLY FLOW ALOFT WE`LL LIKELY SEE A MIX OF SUN AND CLOUDS AND TEMPS RUNNING NEAR NORMAL WITH HIGHS IN THE 40S AND LOWS IN THE 20S TO LOW 30S. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... THROUGH 12Z SATURDAY...GENERALLY VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS. WIDESPREAD BKN-OVC VFR DECK THIS AFTERNOON WITH A SOME ISOLATED SHOWERS OUT THERE ASSOCIATED WITH A WEAK DISTURBANCE PASSING THROUGH THE FLOW ALOFT. AS THIS EXITS THE REGION TO THE EAST LATER THIS EVENING AND HIGH PRESSURE BUILDS IN...SKIES WILL BEGIN TO CLEAR FROM WEST TO EAST AFTER 22Z AT KMSS...AND BY 02/03Z AT KMPV/KRUT. FOR THE REMAINDER OF THE OVERNIGHT HOURS...GOOD LIKELIHOOD OF SOME BR FORMING WITH CLEARING SKIES...ABATING WINDS AND LOTS OF SOIL MOISTURE ACROSS THE REGION. DON`T THINK WE`LL SEE ANYTHING LOWER THEN MVFR THOUGH AS BOUNDARY LAYER WINDS STAY AROUND 5-10KTS UP TO 1 KFT. AFTER 14Z...CLEAR SKIES AND LIGHT NW WINDS OF 5-10 KTS IS EXPECTED FOR SATURDAY. OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY... 18Z SATURDAY THROUGH 18Z SUNDAY...VFR CONDITIONS UNDER HIGH PRESSURE. 18Z SUNDAY THROUGH 12Z WEDNESDAY...FRONTAL SYSTEM MOVING THROUGH SOUTHERN ONTARIO/QUEBEC WILL BRING LOWERING CEILINGS AND MVFR CONDITIONS IN SCATTERED RAIN/SNOW SHOWERS. 12Z WEDNESDAY THROUGH 00Z THURSDAY...MVFR TRENDING TO VFR AS HIGH PRESSURE BUILDS INTO THE REGION. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS/LOCONTO SHORT TERM...BANACOS LONG TERM...LAHIFF AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
106 PM EDT FRI MAR 29 2013 .SYNOPSIS... SURFACE HIGH PRESSURE WILL CONTINUE TO MOVE SLOWLY EAST THROUGH SATURDAY. AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE REGION OVERNIGHT THROUGH EARLY SATURDAY. A WARM FRONT LIFTS NORTH ACROSS PARTS OF THE CAROLINAS SUNDAY...WITH A WEAK COLD FRONT SWEEPING EAST OVER THE REGION SUNDAY AFTERNOON AND SUNDAY NIGHT. && .NEAR TERM /THROUGH SATURDAY/... AS OF 955 AM FRIDAY... THROUGH TONIGHT: THE LATEST SURFACE ANALYSIS SHOWED THE SURFACE RIDGE OF HIGH PRESSURE DIRECTLY OVER CENTRAL NORTH CAROLINA...AND THIS WILL GRADUALLY MOVE TO THE EAST DURING THE AFTERNOON AS MID-LEVEL SHORTWAVE APPROACHES THE AREA FROM THE WEST AND NORTHWEST. IR IMAGES SHOW A SMALL REGION OF COLD-TOPPED CLOUDS ASSOCIATED WITH PRECIPITATION OVER PARTS OF KENTUCKY AND TENNESSEE...THOUGH GUIDANCE SUGGESTS THESE CLOUDS SHOULD WARM AND PRECIPITATION WEAKEN AS DRY AIR IS ENCOUNTERED TO THE EAST. THE MORNING KGSO SOUNDING SHOWED A PRECIPITABLE WATER VALUE UNDER A QUARTER-INCH...AND CENTRAL NORTH CAROLINA WAS REGIONALLY THE MINIMUM IN SURFACE THETA-E...ALONG WITH BUFR SOUNDINGS FROM THE NAM AND THE GFS MAINTAINING A FAIRLY DRY AIR MASS THROUGH THE AFTERNOON. A LARGE PATCH OF COOL HIGH SC/LOW AC TOWARD KRZZ AND KETC SHOULD GRADUALLY SHIFT EAST-SOUTHEAST LATE THIS MORNING AND THIS AFTERNOON IN CONCERT WITH THE LOW-LEVEL MOISTURE FIELDS OF THE RUC AND NAM...SUCH THAT MOST OF CENTRAL NORTH CAROLINA WILL SEE CONSIDERABLE SUNSHINE FOR MUCH OF THE DAY. MID-LEVEL CLOUDS WILL INCREASE LATE...AND WHILE MOISTURE INCREASES IN THE ICE NUCLEATION ZONE BETWEEN -10C AND -15C VERY LATE TODAY AND ESPECIALLY THIS EVENING...THE DEPTH OF MOISTURE IS SHALLOW WITH DRY AIR REMAINING IN THE BOUNDARY LAYER. KEPT HIGH TEMPERATURES AS IS THOUGH THE IMMEDIATE TRIAD MAY BE ON THE HIGH END OF THE EXPECTED RANGE...BUT GOOD SUN FOR MUCH OF THE DAY AND WEST WINDS WITH A FEW GUSTS IN THE LOWER TEENS KTS SHOULD HELP WARM THE AIR MASS. THE LATEST BUFR SOUNDINGS FROM THE NAM AND THE GFS SUGGEST THAT THE SOUTHWEST PIEDMONT INTO THE SANDHILLS HAVE A CHANCE OF SPRINKLES OVERNIGHT. TOWARD KGSO...KRDU...AND KRWI...THE MOISTURE DEPTH REMAINS SHALLOW...HOWEVER...TOWARD KFAY...ON BOTH MODELS THE DEPTH OF MOISTURE IS GREATER WITH ALSO GREATER MOISTURE IN THE BOUNDARY LAYER. WITH QPF FORECAST BY BOTH MODELS AS WELL...FOR NOW HAVE INTRODUCED SPRINKLES AND MAY HAVE TO INCREASE POPS INTO THE CHANCE CATEGORY FOR PARTS OF THIS AREA IN SUBSEQUENT FORECASTS...WHICH COULD LINGER INTO PART OF SATURDAY MORNING. THE INCREASE IN CLOUD COVER SHOULD LEAD TO WARMER OVERNIGHT LOW TEMPERATURES THAN PREVIOUS NIGHTS...WITH LOWS GENERALLY IN THE UPPER 30S TO LOWER 40S. -DJF SATURDAY: SURFACE HIGH PRESSURE CENTERED TO THE NORTH OF THE AREA SATURDAY MORNING WILL QUICKLY SHIFT OFFSHORE ON SATURDAY AFTERNOON RESULTING IN A RENEWED SOUTHERLY/SOUTHWESTERLY RETURN FLOW AFTER A BRIEF PERIOD OF NORTHERLY SURFACE FLOW BEHIND THE AFOREMENTIONED SURFACE TROUGH. HOWEVER... GIVEN LINGERING LOW LEVEL MOISTURE BELOW THE SUBSIDENCE INVERSION AROUND 800 MB ALONG WITH INCREASING MID AND HIGH CLOUDS IN ADVANCE OF A SYSTEM APPROACHING THE AREA FROM THE WEST WILL HELP KEEP SKIES PARTLY SUNNY DURING THE AFTERNOON. AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO BE AROUND 10 TO 15 METERS BELOW NORMAL AT LEAST. THUS... GIVEN THIS AND THE CLOUD COVER WILL CONTINUE TO TREND FORECAST HIGHS FOR SATURDAY A LITTLE BIT BELOW STATISTICAL GUIDANCE VALUES. THIS YIELDS HIGH TEMPS IN THE LOWER TO MID 60S ACROSS THE AREA. -BSD && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 305 AM FRIDAY... SATURDAY NIGHT INTO SUNDAY...INCREASING LOW LEVEL WAA COUPLED WITH MODEST MOISTURE TRANSPORT OFF THE NE GULF OF MEXICO AND ATLANTIC WILL AID IN THE DEVELOPMENT OF SPOTTY RAIN SHOWERS LATE SATURDAY NIGHT INTO SUNDAY MORNING...MAINLY ACROSS THE SOUTHERN AND WESTERN SECTIONS OF CENTRAL NC. INCREASING/THICKENING CLOUD COVERAGE AND A LIGHT SLY SFC WIND WILL RESULT IN MIN TEMPS SATURDAY NIGHT ABOUT 10 DEGREES WARMER THAN TONIGHT. LATER SUNDAY...A WEAK MID LEVEL TROUGH WILL CROSS THE REGION. THIS FEATURE INTERACTING WITH THE AVAILABLE MOISTURE AND WEAK INSTABILITY WILL TRIGGER ADDITIONAL SHOWER ACTIVITY. EXPECT SHOWER COVERAGE TO BE A LITTLE MORE IN THE NORTHERN PIEDMONT DUE TO CLOSE PROXIMITY OF A STALLED SURFACE BOUNDARY ACROSS SOUTHERN VA. SHOWER COVERAGE/INTENSITY SHOULD DIMINISH WEST-TO-EAST BY MID-LATE AFTERNOON AS THE MID LEVEL TROUGH EXITS THE REGION. RAIN TOTALS APPEAR MEAGER THOUGH DUE TO LACK OF STRONG CONVERGENCE IN THE LOW-MID LEVELS OF THE ATMOSPHERE. RAINFALL SHOULD TOTAL UNDER A QUARTER OF AN INCH WITH MOST LOCATIONS MEASURING LESS THAN A TENTH OF AN INCH. IN SPITE OF CONSIDERABLE CLOUDINESS AND SCATTERED SHOWERS...MAX TEMPS SUNDAY WILL BE JUST A FEW DEGREES SHY OF NORMAL...MAINLY IN THE MID-UPPER 60S. IF SHOWER COVERAGE IS MORE EXTENSIVE THAN CURRENT THINKING...THIS MAY HOLD DOWN TEMPS BY 4-6 DEGREES...ESPECIALLY ACROSS THE NW. SUNDAY NIGHT AND MONDAY...SUBSIDENCE IN WEAK OF DEPARTING MID LEVEL TROUGH ALONG WITH MEAN WLY FLOW WILL RESULT IN DECREASING CLOUD COVERAGE SUNDAY NIGHT INTO MONDAY. RESIDUAL SFC MOISTURE AND CLEARING SKIES ALOFT MAY ALLOW FOR THE DEVELOPMENT OF PATCHY FOG BY EARLY MONDAY. A LIGHT SW SFC FLOW ALONG WITH PATCHY CLOUD COVER SHOULD RESULT IN FAIRLY MILD OVERNIGHT TEMPS (COMPARED TO THE PAST TWO WEEKS). MIN TEMPS GENERALLY 50-55. A MIXTURE OF CLOUDS/SUN ON MONDAY PLUS A STEADY SW WIND OCCASIONALLY GUSTING BETWEEN 20-25 MPH WILL BOOST TEMPS TO NEAR OR SLIGHTLY ABOVE NORMAL (NEAR 70-LOWER 70S). AFTERNOON HEATING MAY TRIGGER A SHOWER OR TWO BUT MOST LOCATIONS WILL REMAIN DRY. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... AS OF 305 AM FRIDAY... MONDAY NIGHT THROUGH TUESDAY NIGHT...A MODERATE TO STRONG S/W IN THE NORTHERN BRANCH OF POLAR JET CROSSING THE GREAT LAKES WILL AID TO DRIVE THE STALLED SFC BOUNDARY ACROSS SOUTHERN VA THROUGH CENTRAL NC LATE MONDAY NIGHT INTO TUESDAY. GFS MUCH QUICKER WITH THIS FRONTAL MOVEMENT...ABOUT 6-8 HOURS FASTER COMPARED TO THE ECMWF. ECMWF HAS BACKING OF OTHER MODELS WHILE GFS APPEARS TO BE A SOUTHERN/EASTERN OUTLIER BY TUESDAY. THUS WILL FAVOR THE SLOWER FRONTAL ARRIVAL TIME. THIS REQUIRES SOME ADJUSTMENT TO MIN TEMPS MONDAY NIGHT. WILL RAISE MIN TEMPS ABOUT 5 DEGREES FROM PREVIOUS FORECAST (WITH THE POTENTIAL FOR MIN TEMPS TO BE AN ADDITIONAL 5-7 DEGREES WARMER). MIN TEMPS UPPER 40S TO LOWER 50S. COOL/MOIST NE FLOW BEHIND THE BOUNDARY WILL RESULT IN A DREARY DAY TUESDAY WITH PATCHES OF LIGHT RAIN PROBABLE IN THE HYBRID DAMMING SCENARIO. TEMPS WILL BE MUCH COOLER (ABOUT 20 DEGREES) COMPARED TO MONDAY WITH DAYTIME TEMPS 50-55. FOR MANY LOCATIONS...CALENDER DAY HIGH TEMPS WILL LIKELY OCCUR BETWEEN MIDNIGHT-8 AM. EXPECT IMPROVING CONDITIONS LATE TUESDAY INTO TUESDAY NIGHT AS SFC FRONT SLIDES FARTHER AWAY AND MID LEVEL TROUGH CROSSES THE REGION. MIN TEMPS TUESDAY NIGHT LOW-MID 30S. WEDNESDAY INTO THURSDAY WILL FEATURE DRY AND COOL CONDITIONS AS SURFACE HIGH OVER THE CENTRAL U.S. BUILDS INTO THE CAROLINAS AND BASE OF L/W TROUGH SETTLES OVERHEAD. THICKNESSES WEDNESDAY CLOSE TO 40M BELOW NORMAL WITH A MODEST RECOVERY ON THU. THIS SUGGEST AFTERNOON TEMPS WELL BELOW NORMAL FOR EARLY APRIL. MAX TEMPS 50-55 WEDNESDAY AND LOW-MID 50S THURSDAY. EXPECT MIN TEMPS EARLY THU IN THE 30-35 DEGREE RANGE. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AS OF 105 PM FRIDAY... VFR CONDITIONS ARE ANTICIPATED THROUGH THE 18Z VALID TAF PERIOD. MID-LEVEL CLOUDS WILL INCREASE OVER CENTRAL NORTH CAROLINA...AND AS AN UPPER-LEVEL DISTURBANCE MOVES INTO AND THROUGH THE REGION LATE TONIGHT AND EARLY SATURDAY...THERE SHOULD BE AREAS OF LIGHT RAIN MAINLY TOWARD KFAY. MODEL GUIDANCE SUGGESTS THAT CONDITIONS SHOULD REMAIN PREDOMINANTLY VFR IN THE LIGHT RAIN...ALTHOUGH THERE IS CERTAINLY A MODEST CHANCE OF MVFR CONDITIONS IN CLOUDS AND/OR VISIBILITY AT KFAY MAINLY BETWEEN 10Z AND 16Z SATURDAY. BEYOND THE 18Z VALID TAF PERIOD...CHANCES FOR ADVERSE AVIATION CONDITIONS INCLUDING IFR CONDITIONS INCREASE FOR LATE SATURDAY NIGHT AND SUNDAY MORNING. AHEAD OF A WARM FRONT...THERE IS SOME POTENTIAL FOR LOW-LEVEL WIND SHEAR AS WELL DURING THE SAME TIME FRAME...WITH VEERING OF THE WINDS ALOFT AND AN INCREASE IN SPEED THROUGH THE LOW LEVELS OF THE ATMOSPHERE. A FEW THUNDERSTORMS ARE ALSO POSSIBLE SUNDAY AHEAD OF A COLD FRONT. BEYOND SUNDAY...THERE IS ANOTHER CHANCE FOR IFR CONDITIONS OVERNIGHT MONDAY INTO EARLY TUESDAY AHEAD OF ANOTHER COLD FRONT THAT WILL PUSH THROUGH CENTRAL NORTH CAROLINA. CONDITIONS ARE MOST LIKELY VFR DURING THE DAY MONDAY...AND AGAIN FOR WEDNESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF/BSD SHORT TERM...WSS LONG TERM...WSS AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
956 AM EDT FRI MAR 29 2013 .SYNOPSIS... HIGH PRESSURE WILL MOVE ACROSS THE REGION TODAY AND OFF THE SOUTHEAST COAST SATURDAY. AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST LATE TODAY...MOVING THROUGH THE REGION OVERNIGHT AND EARLY SATURDAY. A FRONTAL SYSTEM WILL APPROACH FROM THE WEST LATE SATURDAY AND MOVE SLOWLY THROUGH THE AREA SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... AS OF 955 AM FRIDAY... THROUGH TONIGHT: THE LATEST SURFACE ANALYSIS SHOWED THE SURFACE RIDGE OF HIGH PRESSURE DIRECTLY OVER CENTRAL NORTH CAROLINA...AND THIS WILL GRADUALLY MOVE TO THE EAST DURING THE AFTERNOON AS MID-LEVEL SHORTWAVE APPROACHES THE AREA FROM THE WEST AND NORTHWEST. IR IMAGES SHOW A SMALL REGION OF COLD-TOPPED CLOUDS ASSOCIATED WITH PRECIPITATION OVER PARTS OF KENTUCKY AND TENNESSEE...THOUGH GUIDANCE SUGGESTS THESE CLOUDS SHOULD WARM AND PRECIPITATION WEAKEN AS DRY AIR IS ENCOUNTERED TO THE EAST. THE MORNING KGSO SOUNDING SHOWED A PRECIPITABLE WATER VALUE UNDER A QUARTER-INCH...AND CENTRAL NORTH CAROLINA WAS REGIONALLY THE MINIMUM IN SURFACE THETA-E...ALONG WITH BUFR SOUNDINGS FROM THE NAM AND THE GFS MAINTAINING A FAIRLY DRY AIR MASS THROUGH THE AFTERNOON. A LARGE PATCH OF COOL HIGH SC/LOW AC TOWARD KRZZ AND KETC SHOULD GRADUALLY SHIFT EAST-SOUTHEAST LATE THIS MORNING AND THIS AFTERNOON IN CONCERT WITH THE LOW-LEVEL MOISTURE FIELDS OF THE RUC AND NAM...SUCH THAT MOST OF CENTRAL NORTH CAROLINA WILL SEE CONSIDERABLE SUNSHINE FOR MUCH OF THE DAY. MID-LEVEL CLOUDS WILL INCREASE LATE...AND WHILE MOISTURE INCREASES IN THE ICE NUCLEATION ZONE BETWEEN -10C AND -15C VERY LATE TODAY AND ESPECIALLY THIS EVENING...THE DEPTH OF MOISTURE IS SHALLOW WITH DRY AIR REMAINING IN THE BOUNDARY LAYER. KEPT HIGH TEMPERATURES AS IS THOUGH THE IMMEDIATE TRIAD MAY BE ON THE HIGH END OF THE EXPECTED RANGE...BUT GOOD SUN FOR MUCH OF THE DAY AND WEST WINDS WITH A FEW GUSTS IN THE LOWER TEENS KTS SHOULD HELP WARM THE AIR MASS. THE LATEST BUFR SOUNDINGS FROM THE NAM AND THE GFS SUGGEST THAT THE SOUTHWEST PIEDMONT INTO THE SANDHILLS HAVE A CHANCE OF SPRINKLES OVERNIGHT. TOWARD KGSO...KRDU...AND KRWI...THE MOISTURE DEPTH REMAINS SHALLOW...HOWEVER...TOWARD KFAY...ON BOTH MODELS THE DEPTH OF MOISTURE IS GREATER WITH ALSO GREATER MOISTURE IN THE BOUNDARY LAYER. WITH QPF FORECAST BY BOTH MODELS AS WELL...FOR NOW HAVE INTRODUCED SPRINKLES AND MAY HAVE TO INCREASE POPS INTO THE CHANCE CATEGORY FOR PARTS OF THIS AREA IN SUBSEQUENT FORECASTS...WHICH COULD LINGER INTO PART OF SATURDAY MORNING. THE INCREASE IN CLOUD COVER SHOULD LEAD TO WARMER OVERNIGHT LOW TEMPERATURES THAN PREVIOUS NIGHTS...WITH LOWS GENERALLY IN THE UPPER 30S TO LOWER 40S. -DJF SATURDAY: SURFACE HIGH PRESSURE CENTERED TO THE NORTH OF THE AREA SATURDAY MORNING WILL QUICKLY SHIFT OFFSHORE ON SATURDAY AFTERNOON RESULTING IN A RENEWED SOUTHERLY/SOUTHWESTERLY RETURN FLOW AFTER A BRIEF PERIOD OF NORTHERLY SURFACE FLOW BEHIND THE AFOREMENTIONED SURFACE TROUGH. HOWEVER... GIVEN LINGERING LOW LEVEL MOISTURE BELOW THE SUBSIDENCE INVERSION AROUND 800 MB ALONG WITH INCREASING MID AND HIGH CLOUDS IN ADVANCE OF A SYSTEM APPROACHING THE AREA FROM THE WEST WILL HELP KEEP SKIES PARTLY SUNNY DURING THE AFTERNOON. AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO BE AROUND 10 TO 15 METERS BELOW NORMAL AT LEAST. THUS... GIVEN THIS AND THE CLOUD COVER WILL CONTINUE TO TREND FORECAST HIGHS FOR SATURDAY A LITTLE BIT BELOW STATISTICAL GUIDANCE VALUES. THIS YIELDS HIGH TEMPS IN THE LOWER TO MID 60S ACROSS THE AREA. -BSD && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 305 AM FRIDAY... SATURDAY NIGHT INTO SUNDAY...INCREASING LOW LEVEL WAA COUPLED WITH MODEST MOISTURE TRANSPORT OFF THE NE GULF OF MEXICO AND ATLANTIC WILL AID IN THE DEVELOPMENT OF SPOTTY RAIN SHOWERS LATE SATURDAY NIGHT INTO SUNDAY MORNING...MAINLY ACROSS THE SOUTHERN AND WESTERN SECTIONS OF CENTRAL NC. INCREASING/THICKENING CLOUD COVERAGE AND A LIGHT SLY SFC WIND WILL RESULT IN MIN TEMPS SATURDAY NIGHT ABOUT 10 DEGREES WARMER THAN TONIGHT. LATER SUNDAY...A WEAK MID LEVEL TROUGH WILL CROSS THE REGION. THIS FEATURE INTERACTING WITH THE AVAILABLE MOISTURE AND WEAK INSTABILITY WILL TRIGGER ADDITIONAL SHOWER ACTIVITY. EXPECT SHOWER COVERAGE TO BE A LITTLE MORE IN THE NORTHERN PIEDMONT DUE TO CLOSE PROXIMITY OF A STALLED SURFACE BOUNDARY ACROSS SOUTHERN VA. SHOWER COVERAGE/INTENSITY SHOULD DIMINISH WEST-TO-EAST BY MID-LATE AFTERNOON AS THE MID LEVEL TROUGH EXITS THE REGION. RAIN TOTALS APPEAR MEAGER THOUGH DUE TO LACK OF STRONG CONVERGENCE IN THE LOW-MID LEVELS OF THE ATMOSPHERE. RAINFALL SHOULD TOTAL UNDER A QUARTER OF AN INCH WITH MOST LOCATIONS MEASURING LESS THAN A TENTH OF AN INCH. IN SPITE OF CONSIDERABLE CLOUDINESS AND SCATTERED SHOWERS...MAX TEMPS SUNDAY WILL BE JUST A FEW DEGREES SHY OF NORMAL...MAINLY IN THE MID-UPPER 60S. IF SHOWER COVERAGE IS MORE EXTENSIVE THAN CURRENT THINKING...THIS MAY HOLD DOWN TEMPS BY 4-6 DEGREES...ESPECIALLY ACROSS THE NW. SUNDAY NIGHT AND MONDAY...SUBSIDENCE IN WEAK OF DEPARTING MID LEVEL TROUGH ALONG WITH MEAN WLY FLOW WILL RESULT IN DECREASING CLOUD COVERAGE SUNDAY NIGHT INTO MONDAY. RESIDUAL SFC MOISTURE AND CLEARING SKIES ALOFT MAY ALLOW FOR THE DEVELOPMENT OF PATCHY FOG BY EARLY MONDAY. A LIGHT SW SFC FLOW ALONG WITH PATCHY CLOUD COVER SHOULD RESULT IN FAIRLY MILD OVERNIGHT TEMPS (COMPARED TO THE PAST TWO WEEKS). MIN TEMPS GENERALLY 50-55. A MIXTURE OF CLOUDS/SUN ON MONDAY PLUS A STEADY SW WIND OCCASIONALLY GUSTING BETWEEN 20-25 MPH WILL BOOST TEMPS TO NEAR OR SLIGHTLY ABOVE NORMAL (NEAR 70-LOWER 70S). AFTERNOON HEATING MAY TRIGGER A SHOWER OR TWO BUT MOST LOCATIONS WILL REMAIN DRY. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... AS OF 305 AM FRIDAY... MONDAY NIGHT THROUGH TUESDAY NIGHT...A MODERATE TO STRONG S/W IN THE NORTHERN BRANCH OF POLAR JET CROSSING THE GREAT LAKES WILL AID TO DRIVE THE STALLED SFC BOUNDARY ACROSS SOUTHERN VA THROUGH CENTRAL NC LATE MONDAY NIGHT INTO TUESDAY. GFS MUCH QUICKER WITH THIS FRONTAL MOVEMENT...ABOUT 6-8 HOURS FASTER COMPARED TO THE ECMWF. ECMWF HAS BACKING OF OTHER MODELS WHILE GFS APPEARS TO BE A SOUTHERN/EASTERN OUTLIER BY TUESDAY. THUS WILL FAVOR THE SLOWER FRONTAL ARRIVAL TIME. THIS REQUIRES SOME ADJUSTMENT TO MIN TEMPS MONDAY NIGHT. WILL RAISE MIN TEMPS ABOUT 5 DEGREES FROM PREVIOUS FORECAST (WITH THE POTENTIAL FOR MIN TEMPS TO BE AN ADDITIONAL 5-7 DEGREES WARMER). MIN TEMPS UPPER 40S TO LOWER 50S. COOL/MOIST NE FLOW BEHIND THE BOUNDARY WILL RESULT IN A DREARY DAY TUESDAY WITH PATCHES OF LIGHT RAIN PROBABLE IN THE HYBRID DAMMING SCENARIO. TEMPS WILL BE MUCH COOLER (ABOUT 20 DEGREES) COMPARED TO MONDAY WITH DAYTIME TEMPS 50-55. FOR MANY LOCATIONS...CALENDER DAY HIGH TEMPS WILL LIKELY OCCUR BETWEEN MIDNIGHT-8 AM. EXPECT IMPROVING CONDITIONS LATE TUESDAY INTO TUESDAY NIGHT AS SFC FRONT SLIDES FARTHER AWAY AND MID LEVEL TROUGH CROSSES THE REGION. MIN TEMPS TUESDAY NIGHT LOW-MID 30S. WEDNESDAY INTO THURSDAY WILL FEATURE DRY AND COOL CONDITIONS AS SURFACE HIGH OVER THE CENTRAL U.S. BUILDS INTO THE CAROLINAS AND BASE OF L/W TROUGH SETTLES OVERHEAD. THICKNESSES WEDNESDAY CLOSE TO 40M BELOW NORMAL WITH A MODEST RECOVERY ON THU. THIS SUGGEST AFTERNOON TEMPS WELL BELOW NORMAL FOR EARLY APRIL. MAX TEMPS 50-55 WEDNESDAY AND LOW-MID 50S THURSDAY. EXPECT MIN TEMPS EARLY THU IN THE 30-35 DEGREE RANGE. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 620 AM FRIDAY... 24 HOUR TAF PERIOD: VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE 24 HOUR TAF PERIOD. SURFACE HIGH PRESSURE WILL SLOWLY SLIP TO THE SOUTH AND SOUTHEAST OF THE AREA TODAY... ALLOWING LIGHT NORTH TO NORTHWESTERLY WINDS THIS MORNING TO BECOME WEST TO SOUTHWESTERLY BY AFTERNOON IN THE 6 TO 10 KT RANGE... WITH POSSIBLY A FEW GUSTS OF AROUND 15 KTS OR SO DURING THE AFTERNOON (BEST CHANCE OF ANY WINDS GUSTS AT KINT/KGSO). EXPECT CLOUD COVER WILL BEGIN TO INCREASE ACROSS THE AREA IN THE MID TO LATE AFTERNOON AS A WEAK UPPER LEVEL DISTURBANCE APPROACHES THE AREA ALONG WITH AN ACCOMPANYING WEAK SURFACE TROUGH... WHICH IS EXPECTED TO MOVE THROUGH THE AREA LATE THIS EVENING INTO EARLY SATURDAY MORNING... WITH SURFACE HIGH PRESSURE BUILDING INTO THE AREA IN THE WAKE OF THE SYSTEM. THUS... EXPECT AN INCREASE IN CLOUD COVER (WITH MOSTLY TO CLOUDY TO EVEN OVERCAST SKIES EXPECTED LATE IN THE DAY INTO THE OVERNIGHT)... GENERALLY 5 KFT OR ABOVE... TO ACCOMPANY THE DISTURBANCE. OUTLOOK: VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH SATURDAY. LOW LEVEL MOISTENING WILL OCCUR SATURDAY NIGHT AS THE SURFACE RIDGE MOVES OFFSHORE... AND SUB-VFR CONDITIONS WITH FOG/STRATUS ARE EXPECTED TO FORM TOWARD SUNDAY MORNING WITH INCREASE CHANCES FOR SHOWERS. PERIODS OF SUB-VFR CONDITIONS ALONG WITH PERIODS OF SHOWERS ARE EXPECTED SUNDAY THROUGH TUESDAY AS A FRONTAL SYSTEM MOVES INTO THE AREA AND STALLS SOMEWHERE ACROSS THE REGION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF/BSD SHORT TERM...WSS LONG TERM...WSS AVIATION...BSD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
324 PM CDT FRI MAR 29 2013 .SHORT TERM... MAIN CHALLENGE FOR THIS FORECAST CONTINUES TO BE PERSISTENT FOG AND TEMPERATURES. SOUNDINGS CONTINUE TO SHOW STRONG INVERSION NEAR THE SURFACE WITH LIGHT WINDS...THUS EXPECT AREAS OF FOG TO CONTINUE IN THE DVL BASIN AND ALONG THE RED RIVER VALLEY. HOWEVER...WILL LET THE ADVISORY EXPIRE AT 21Z AS MOST AREAS HAVE IMPROVED. FOR THIS EVENING INTO TONIGHT...A WAVE ASSOCIATED WITH AN AREA OF LOW PRESSURE IS EXPECTED TO MOVE ACROSS THE AREA TONIGHT. ANALYSIS OF THE 295K ISENTROPIC SFC SHOWS DECENT UPGLIDE AND FAVORABLE CONDENSATION PRESSURE DEFICITS POINTING TOWARD PCPN OVERNIGHT. FCST SOUNDINGS SHOW A WARM LAYER ALOFT AND IS SUFFICIENTLY DEEP TO FAVOR -ZR ACROSS THE SRN ZONES AND IS REFLECTED IN THE GRIDS. FOR SATURDAY...GFS AND ECMWF SHOW GOOD COLD ADVECTION BEHIND THE FRONT WITH BREEZY CONDITIONS AND EXPECT THE COLD AIR WILL OFFSET ANY SOLAR. WITH A SIGNIFICANT SNOWPACK OVER THE FA...WILL KEEP TEMPS A BIT COOLER WITH LITTLE RECOVERY DURING THE DAY. OTHERWISE...EXPECT LOWS SUNDAY MORNING TO BE NEAR SINGLE DIGITS ACROSS THE NORTH. THE SFC RIDGE LOOKS TO CROSS THE AREA RAPIDLY AND RETURN FLOW ON MONDAY WILL HELP TEMPS RECOVER A BIT BUT REMAIN BELOW SEASONAL AVERAGES. LITTLE PCPN IS EXPECTED FOR THE REMAINDER OF THE WEEKEND. .LONG TERM (TUE THRU FRI)... THROUGH MUCH OF THE EXTENDED PERIOD THE VARIOUS MODELS ARE IN DECENT AGREEMENT THROUGH MOST OF THIS PERIOD. LIKE THE GFS BLENDED WITH BC-ECMWF. MODELS DIVERGE ON SOLUTIONS TOWARD THE END OF THE PERIOD AND BEYOND. AT THE START OF THE EXTENDED A SHARP TROUGH OVER THE GREAT LAKES WITH RESULTING NORTHWEST FLOW OVER CWFA. ECMWF/GEM/GFS/DGEX ALL IN GOOD AGREEMENT WITH SURFACE HIGH NORTH TO SOUTH THROUGH FA. LIGHT WINDS AND DECREASING CLOUD COVER FORECAST SO HAVE OPTED TO LOWER MINS TUESDAY MORNING ABOUT 5F...CLOSER TO BC-GRIDS WHICH HAVE BEEN PERFORMING BETTER. RETURN FLOW BEGINS BY 00Z WEDNESDAY BUT GUIDANCE SUGGESTS LOW LEVEL WAA SLOW TO CRANK UP. THEREFORE HAVE LOWERED MAXES ABOUT 2F TO 4F... AGAIN LEANING ON A BC-BLEND. LOW LEVEL WAA DOES KICK IN PRETTY STRONGLY BY 12Z WEDNESDAY. WHEN COMBINED WITH APPROACHING SHORTWAVE ...LOW LEVEL LIFT...850-500MB OMEGA AND LOWER COND PRES DEF LIKE THE IDEA OF SLGHT CHC/CHC POPS. LIKELY A MIX OF RA/SN...PERHAPS ALL RA AFTERNOON...BUT LIGHT AMOUNTS FORECAST. MODEST BOUNDARY LAYER TEMPERATURE DROP OF 4C TO 6C FORECAST BETWEEN WEDNESDAY AND THURSDAY...SO HAVE LOWERED THURSDAY MAXES ACCORDINGLY. I HAVE ALSO UPPED WIND SPEEDS A TAD AS THE LOW LEVEL CAA APPEARS FAIRLY IMPRESSIVE ON ALL MODELS. THIS FORECAST PERIOD ENDS WITH MODEL DIFFERENCES BECOMING MORE GLARING. WITH RETURN FLOW...INCREASING CLOUDS AND MOISTURE AS STRONG LOW LEVEL BOUNDARY SET THE STAGE FOR LIGHT -RA/-SN. ECMWF HAS A MORE PROGRESSIVE AND FARTHER NORTH SYSTEM WHILE GFS MUCH SLOWER AND FARTHER SOUTH. FOLLOWED GUIDANCE TO PAINT SWATH OF PRECIPITATION MOVING WEST TO EAST LATE THURSDAY INTO FRIDAY. MADE A RASN MIX DURING THE OVERNIGHT THURSDAY INTO EARLY FRIDAY. && .AVIATION... CONDITIONS ARE ALL OVER THE PLACE AS FOG DISSIPATES IN USUAL CHAOTIC MANNER. WELL DEFINED TONGUE OF IFR CIG/VSBY WITHIN THE RRV FLOOR SHRINKING FROM OUTSIDE INWARD. BIG QUESTION IS WILL LIFR FOG AND CIGS REDEVELOP AFTER SUNSET. GFS AND LAMP-MOS RE-EXPAND THE LOW CLOUDS AFTER 02Z. WILL FOLLOW THE LAMP/GFS MOS AS IT HAS HAD AN OKAY HANDLE ON THE CONDITIONS. HRRR HAS BEEN TOO EXPANSIVE AND GENERALLY IGNORED. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR NDZ006>008- 014>016-024-026>030-038-039-049-052>054. MN...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR MNZ001>004- 007-029. && $$ HOPKINS/EWENS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
109 PM CDT FRI MAR 29 2013 .UPDATE... ISSUED AT 109 PM CDT FRI MAR 29 2013 TRIMMED THE WESTERN FRINGE OF THE DENSE FOG ADVISORY AS VISIBILITIES HAVE RECENTLY IMPROVED. JAMESTOWN IS STILL REPORTING ONE QUARTER MILE VISIBILITIES WITH SLOW IMPROVEMENT EXPECTED THROUGH THE AFTERNOON. AS A RESULT...EXTENDED THE DENSE FOG ADVISORY FOR THE EXTREME EASTERN CWA UNTIL 4 PM CDT. WILL CONTINUE TO MONITOR AFTERNOON OBS/TRENDS. FURTHERMORE...ADDED A SLIGHT CHANCE OF THUNDER SOUTHWEST AS THE LATEST SHORT RANGE MODELS PROG CAPE APPROACHING 200 J/KG AND SHOWALTER INDICES APPROACHING ZERO THIS AFTERNOON. NOT MUCH IF ANY PRECIP ASSOCIATED WITH A SHORTWAVE MOVING ACROSS THE REGION HAS BEEN REACHING THE GROUND. FURTHERMORE...SURFACE TEMPS NEAR TIOGA AND STANLEY ARE RIGHT AT 32 DEGREES. THEREFORE...THINK THE FREEZING RAIN THREAT IS DIMINISHING ACROSS NORTHWESTERN NORTH DAKOTA. HOWEVER...WILL CONTINUE TO HIGHLIGHT THIS ACTIVITY WITH SPECIAL WEATHER STATEMENTS. UPDATE ISSUED AT 1041 AM CDT FRI MAR 29 2013 FOG CONTINUES TO DISSIPATE ACROSS WESTERN AND PORTIONS OF CENTRAL NORTH DAKOTA THIS MORNING. AS A RESULT...CANCELLED THE DENSE FOG ADVISORY FOR AREAS ALONG AND WEST OF HIGHWAY 83. THE KGGW WSR-88D DETECTED AN AREA OF LIGHT PRECIPITATION MOVING EAST ACROSS NORTHEASTERN MONTANA THIS MORNING. THIS ACTIVITY IS EXPECTED TO ENTER NORTHWESTERN NORTH DAKOTA LATER THIS MORNING. HOWEVER...BY THE TIME IT REACHES SAID PORTION OF THE STATE...SURFACE TEMPS MAY BE NEAR OR ABOVE FREEZING. AS A RESULT...WILL HOLD OFF ON A FREEZING RAIN ADVISORY FOR NOW. WILL LIKELY HANDLE THE SITUATION WITH SPECIAL WEATHER STATEMENTS BASED ON SPOTTER REPORTS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 645 AM CDT FRI MAR 29 2013 NO MAJOR CHANGES FROM THE CURRENT FORECAST. DENSE FOG REMAINS ALONG THE MISSOURI RIVER COUNTIES AND ALL POINTS NORTH AND EAST. DID GET A REPORT OF BREAKS IN THE FOG IN MCLEAN COUNTY...BUT OVERALL SFC OBS ARE COMING IN AT 1/4SM OR ZERO. FREEZING RAIN HAS BEEN REPORTED IN GLASGOW MONTANA...AND WILL NEED TO MONITOR IN CASE A FREEZING RAIN ADVISORY BECOMES NEEDED THIS MORNING. RIGHT NOW IT IS UNCERTAIN WHERE THE BEST ACCUMULATING PRECIPITATION WILL FALL OVER MY WEST. THE RAP TAKES IT SOUTH OF THE MISSOURI RIVER WHILE THE EC AND GEM ARE FARTHER NORTH NEAR KISN...AND THE NAM BRINGS THE HIGHER QPF OVER MY FAR NORTHWEST ALONG THE CANADIAN BORDER. && .SHORT TERM...TODAY AND TONIGHT... ISSUED AT 330 AM CDT FRI MAR 29 2013 THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS AFTERNOON WITH A WINTRY MIX NORTH. THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC. THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN AND SLEET ARE POSSIBLE. FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS TONIGHT. .LONG TERM...SATURDAY THROUGH NEXT FRIDAY... ISSUED AT 330 AM CDT FRI MAR 29 2013 WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY. CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS SUNDAY INTO MONDAY. TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR MOVES OFF TO OUR EAST. WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR SOUTHERN CANADA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 109 PM CDT FRI MAR 29 2013 VLIFR CONDITIONS IN FOG WILL CONTINUE AT KJMS THROUGH MID- AFTERNOON. OTHERWISE...ELEVATED SHOWER ACTIVITY WILL CONTINUE TO PUSH ACROSS THE STATE GENERATING VIRGA FROM MID-LEVEL CLOUDS. MOISTURE TRAPPED BENEATH HIGH PRESSURE BUILDING INTO THE REGION TONIGHT MAY GENERATE MVFR CIGS...MAINLY AFTER 06Z SATURDAY. A MIX OF MVFR/VFR CIGS ARE EXPECTED AREAWIDE SATURDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR NDZ005-013- 023-025-037-048-051. && $$ UPDATE...TM SHORT TERM...AYD LONG TERM...NH AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1041 AM CDT FRI MAR 29 2013 .UPDATE... ISSUED AT 1041 AM CDT FRI MAR 29 2013 FOG CONTINUES TO DISSIPATE ACROSS WESTERN AND PORTIONS OF CENTRAL NORTH DAKOTA THIS MORNING. AS A RESULT...CANCELLED THE DENSE FOG ADVISORY FOR AREAS ALONG AND WEST OF HIGHWAY 83. THE KGGW WSR-88D DETECTED AN AREA OF LIGHT PRECIPITATION MOVING EAST ACROSS NORTHEASTERN MONTANA THIS MORNING. THIS ACTIVITY IS EXPECTED TO ENTER NORTHWESTERN NORTH DAKOTA LATER THIS MORNING. HOWEVER...BY THE TIME IT REACHES SAID PORTION OF THE STATE...SURFACE TEMPS MAY BE NEAR OR ABOVE FREEZING. AS A RESULT...WILL HOLD OFF ON A FREEZING RAIN ADVISORY FOR NOW. WILL LIKELY HANDLE THE SITUATION WITH SPECIAL WEATHER STATEMENTS BASED ON SPOTTER REPORTS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 645 AM CDT FRI MAR 29 2013 NO MAJOR CHANGES FROM THE CURRENT FORECAST. DENSE FOG REMAINS ALONG THE MISSOURI RIVER COUNTIES AND ALL POINTS NORTH AND EAST. DID GET A REPORT OF BREAKS IN THE FOG IN MCLEAN COUNTY...BUT OVERALL SFC OBS ARE COMING IN AT 1/4SM OR ZERO. FREEZING RAIN HAS BEEN REPORTED IN GLASGOW MONTANA...AND WILL NEED TO MONITOR IN CASE A FREEZING RAIN ADVISORY BECOMES NEEDED THIS MORNING. RIGHT NOW IT IS UNCERTAIN WHERE THE BEST ACCUMULATING PRECIPITATION WILL FALL OVER MY WEST. THE RAP TAKES IT SOUTH OF THE MISSOURI RIVER WHILE THE EC AND GEM ARE FARTHER NORTH NEAR KISN...AND THE NAM BRINGS THE HIGHER QPF OVER MY FAR NORTHWEST ALONG THE CANADIAN BORDER. && .SHORT TERM...TODAY AND TONIGHT... ISSUED AT 330 AM CDT FRI MAR 29 2013 THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS AFTERNOON WITH A WINTRY MIX NORTH. THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC. THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN AND SLEET ARE POSSIBLE. FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS TONIGHT. .LONG TERM...SATURDAY THROUGH NEXT FRIDAY... ISSUED AT 330 AM CDT FRI MAR 29 2013 WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY. CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS SUNDAY INTO MONDAY. TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR MOVES OFF TO OUR EAST. WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR SOUTHERN CANADA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 645 AM CDT FRI MAR 29 2013 VLIFR CONDITIONS IN FOG WILL CONTINUE AT KMOT AND KJMS THROUGH AT LEAST 18 UTC FRIDAY...WITH SLOW IMPROVEMENT THEREAFTER. VLIFR FOG AT KBIS SHOULD BURN OFF A BIT FASTER...IN THE 15-17 UTC TIMEFRAME WITH THE LACK OF A DEEP SNOWPACK. KISN AND KDIK HAVE REMAINED ON THE FRINGE OF THE FOG BANK THUS FAR TONIGHT...AND ARE EXPECTED TO THROUGH FRIDAY MORNING. THAT SAID...TEMPORARY REDUCTIONS TO IFR CANNOT BE RULED OUT. SCATTERED PRECIPITATION POSSIBLY IN THE FORM OF FREEZING RAIN OR SLEET MAY IMPACT KISN AND KMOT...AND POSSIBLY KJMS FRIDAY EVENING. SCATTERED SHOWERS WITH POSSIBLY AN ISOLATED THUNDERSTORM IS POSSIBLE NEAR KDIK FRIDAY AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NDZ004-005- 012-013-022-023-025-036-037-047-048-050-051. && $$ UPDATE...TM SHORT TERM...AYD LONG TERM...NH AVIATION...AYD/NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
645 AM CDT FRI MAR 29 2013 .UPDATE... ISSUED AT 645 AM CDT FRI MAR 29 2013 NO MAJOR CHANGES FROM THE CURRENT FORECAST. DENSE FOG REMAINS ALONG THE MISSOURI RIVER COUNTIES AND ALL POINTS NORTH AND EAST. DID GET A REPORT OF BREAKS IN THE FOG IN MCLEAN COUNTY...BUT OVERALL SFC OBS ARE COMING IN AT 1/4SM OR ZERO. FREEZING RAIN HAS BEEN REPORTED IN GLASGOW MONTANA...AND WILL NEED TO MONITOR IN CASE A FREEZING RAIN ADVISORY BECOMES NEEDED THIS MORNING. RIGHT NOW IT IS UNCERTAIN WHERE THE BEST ACCUMULATING PRECIPITATION WILL FALL OVER MY WEST. THE RAP TAKES IT SOUTH OF THE MISSOURI RIVER WHILE THE EC AND GEM ARE FARTHER NORTH NEAR KISN...AND THE NAM BRINGS THE HIGHER QPF OVER MY FAR NORTHWEST ALONG THE CANADIAN BORDER. && .SHORT TERM...TODAY AND TONIGHT... ISSUED AT 330 AM CDT FRI MAR 29 2013 THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS AFTERNOON WITH A WINTRY MIX NORTH. THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC. THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN AND SLEET ARE POSSIBLE. FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS TONIGHT. .LONG TERM...SATURDAY THROUGH NEXT FRIDAY... ISSUED AT 330 AM CDT FRI MAR 29 2013 WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY. CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS SUNDAY INTO MONDAY. TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR MOVES OFF TO OUR EAST. WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR SOUTHERN CANADA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 645 AM CDT FRI MAR 29 2013 VLIFR CONDITIONS IN FOG WILL CONTINUE AT KMOT AND KJMS THROUGH AT LEAST 18 UTC FRIDAY...WITH SLOW IMPROVEMENT THEREAFTER. VLIFR FOG AT KBIS SHOULD BURN OFF A BIT FASTER...IN THE 15-17 UTC TIMEFRAME WITH THE LACK OF A DEEP SNOWPACK. KISN AND KDIK HAVE REMAINED ON THE FRINGE OF THE FOG BANK THUS FAR TONIGHT...AND ARE EXPECTED TO THROUGH FRIDAY MORNING. THAT SAID...TEMPORARY REDUCTIONS TO IFR CANNOT BE RULED OUT. SCATTERED PRECIPITATION POSSIBLY IN THE FORM OF FREEZING RAIN OR SLEET MAY IMPACT KISN AND KMOT...AND POSSIBLY KJMS FRIDAY EVENING. SCATTERED SHOWERS WITH POSSIBLY AN ISOLATED THUNDERSTORM IS POSSIBLE NEAR KDIK FRIDAY AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 1 PM CDT /NOON MDT/ THIS AFTERNOON FOR NDZ001>005-009>013-019>023-025-034>037-042-045>048-050-051. && $$ UPDATE...NH AVIATION...AYD/NH SHORT TERM...AYD LONG TERM...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
331 AM CDT FRI MAR 29 2013 .SHORT TERM...TODAY AND TONIGHT... ISSUED AT 330 AM CDT FRI MAR 29 2013 THE CHALLENGES OF THE SHORT TERM ARE HOW LONG THE ONGOING DENSE FOG WILL PERSIST...THE IMPACT OF THE FOG ON TEMPERATURES FOR TODAY AND THE POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST THIS AFTERNOON WITH A WINTRY MIX NORTH. THE RAP AND HRRR HAVE HAD A GOOD HANDLE ON THE EVOLUTION OF THE DENSE FOG ACROSS CENTRAL AND NORTHWEST NORTH DAKOTA THROUGH THE NIGHT...AND WILL FOLLOW THEIR VISIBILITY FORECASTS FROM THEIR LATEST RUN (29/04 UTC). THIS WOULD SUGGEST THAT DENSE FOG...ESPECIALLY OVER THE SNOWPACK MAY HOLD NEAR ONE QUARTER OF A MILE THROUGH 18 UTC. THIS IS SUPPORTED BY THE OBSERVED FOG TRENDS SEEN ON THURSDAY IN A SIMILAR ENVIRONMENT. THUS HAVE EXPANDED THE DENSE FOG ADVISORY THROUGH 18 UTC. WOULD NOT RULE OUT A POSSIBLE EXPANSION IN TIME FOR PORTIONS OF THE ADVISORY LATER INTO THE AFTERNOON AS MID LEVEL CLOUD COVER MAY SLOW DOWN THE BURNING OFF OF THE FOG. IN REGARDS TO TEMPERATURES...WILL USE THE OBSERVED TEMPERATURE PATTERN ON THURSDAY AS A GUIDE...AND WILL LIMIT HIGHS TO THE UPPER 20S ACROSS MUCH OF THE SNOWPACK IMPACTED BY FOG. LIKE THURSDAY...THE SNOW AND FOG FREE SOUTHWEST IS EXPECTED TO WARM INTO THE UPPER 50S TO THE LOWER 60S AS MIXING INCREASES BEHIND A WEAK TROUGH. STEEP LAPSE RATES THROUGH MUCH OF THE TROPOSPHERE SUGGESTS DIURNALLY DRIVEN SHOWER ACTIVITY IS POSSIBLE...WITH ISOLATED THUNDERSTORMS NOT OUT OF THE QUESTION GIVEN THE COOL TEMPERATURES ALOFT AND STEEP LAPSE RATES SUPPORTING AFTERNOON ML CAPE VALUES OF 200-400 J/KG. ELSEWHERE IN REGARDS TO PRECIPITATION TODAY...A WEAK WAVE ACROSS SOUTHWEST SASKATCHEWAN AS OF 08 UTC WILL PROPAGATE SOUTHEAST THROUGH THE DAY. GIVEN THE WEAK FORCING AND DRY LOW LEVELS...PRECIPITATION WITH SCATTERED ACTIVITY WILL BE LIGHT. HOWEVER...WITH A WARM LAYER ALOFT ABOVE THE SUB-FREEZING SURFACE TEMPERATURES OF THE SNOWPACK...FREEZING RAIN AND SLEET ARE POSSIBLE. FOR TONIGHT...BOUNDARY LAYER MIXING ON THE ORDER OF 10 KTS CWA WIDE IN THE WAKE OF THE AFOREMENTIONED SURFACE TROUGH SHOULD HELP TO KEEP TEMPERATURES FROM BOTTOMING OUT TOO FAR...WITH SOME STRATUS ALSO HINTED IN THE 00 UTC DETERMINISTIC GUIDANCE. THUS...FOLLOWED FAIRLY CLOSELY TO A BLEND OF THE 00 UTC DETERMINISTIC MODEL SUITE FOR LOWS TONIGHT. .LONG TERM...SATURDAY THROUGH NEXT FRIDAY... ISSUED AT 330 AM CDT FRI MAR 29 2013 WILL SEE AN ACTIVE FLOW PATTERN THROUGH THE EASTER HOLIDAY WEEKEND AS A CLOSED UPPER LOW MOVES SOUTH ACROSS CENTRAL CANADA ON SATURDAY AND INTO THE GREAT LAKES REGION SUNDAY AND MONDAY. CYCLONIC FLOW ALOFT WILL BRING SEVERAL EMBEDDED S/WVS ACROSS THE NORTHERN PLAINS SATURDAY THROUGH SUNDAY AFTERNOON SO WILL MAINTAIN PRECIP CHANCES. ONLY LIGHT QPF IS DEPICTED. THE UPPER LOW WILL ALSO BRING A SURGE OF COLDER AIR INTO THE NORTHERN PLAINS SUNDAY INTO MONDAY. TEMPERATURES MODERATE BACK TO NORMAL BY MID-WEEK AS THE COLDER AIR MOVES OFF TO OUR EAST. WILL MAINTAIN A DRY FORECAST SUNDAY NIGHT THROUGH TUESDAY NIGHT WITH UPPER LEVEL RIDGING BUILDING ALOFT. FOR MID-WEEK...MODELS DISAGREEING ON A POTENTIAL CLIPPER IMPACTING THE REGION. OPTED TO KEEP THE FORECAST DRY. NEXT CHANCE OF PRECIPITATION ARRIVES AT THE END OF THE WORK WEEK WHEN THE UPPER JET PUSHES SOUTH TO ACROSS FAR SOUTHERN CANADA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 330 AM CDT FRI MAR 29 2013 VLIFR CONDITIONS IN FOG WILL CONTINUE AT KMOT AND KJMS THROUGH AT LEAST 18 UTC FRIDAY...WITH SLOW IMPROVEMENT THEREAFTER. VLIFR FOG AT KBIS SHOULD BURN OFF A BIT FASTER...IN THE 15-17 UTC TIMEFRAME WITH THE LACK OF A DEEP SNOWPACK. KISN AND KDIK HAVE REMAINED ON THE FRINGE OF THE FOG BANK THUS FAR TONIGHT...AND ARE EXPECTED TO THROUGH FRIDAY MORNING. THAT SAID...TEMPORARY REDUCTIONS TO IFR CANNOT BE RULED OUT. SCATTERED PRECIPITATION POSSIBLY IN THE FORM OF FREEZING RAIN OR SLEET MAY IMPACT KISN AND KMOT...AND POSSIBLY KJMS FRIDAY EVENING. SCATTERED SHOWERS WITH POSSIBLY AN ISOLATED THUNDERSTORM IS POSSIBLE NEAR KDIK FRIDAY AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR NDZ001>005-009>013-019>023-025-034>037-042-045>048-050-051. && $$ SHORT TERM/AVIATION...AYD LONG TERM...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1251 AM CDT FRI MAR 29 2013 .UPDATE... ISSUED AT 1240 AM CDT FRI MAR 29 2013 BASED UPON WEBCAMS AND SURFACE OBSERVATIONS THROUGH 0530 UTC...EXPANDED THE DENSE FOG ADVISORY INTO DICKEY...LAMOURE... MCINTOSH...MORTON...MERCER...GRANT...OLIVER AND SIOUX COUNTIES. THE HRRR THROUGH THE NIGHT HAS CONSISTENTLY BEEN HANDLING THE EVOLUTION OF THE FOG WELL...WHICH CONTINUES WITH ITS LATEST 02 UTC RUN. BASED ON THE HRRR...MAY HAVE TO EXTEND THE ADVISORY PAST 15 UTC...ESPECIALLY OVER THE SNOWPACK WITH THE NEXT UPDATE IF ITS FORECAST TRENDS CONTINUE. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 314 PM CDT THU MAR 28 2013 THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM IS FOG TONIGHT AND MIXED PRECIPITATION FOR LATE TONIGHT AND FRIDAY. FOG HAD BEEN PROBLEMATIC TODAY AS THE CURRENT SNOW PACK MAINLY NORTH AND EAST OF THE MISSOURI RIVER WAS PROVIDING LOW LEVEL MOISTURE AND KEEPING THE SURFACE LAYER COOLER. ADDING TO THE COMPLEXITY WAS THE EAST/NORTH LIGHT WIND FLOW WHICH MOVES UP IN ELEVATION ALONG THE COTEAU OVER NORTHERN NORTH DAKOTA TO SOUTH AND WEST OF JAMESTOWN...COOLING JUST ENOUGH TO KEEP LOW CLOUDS AND FOG IN THE AREA. ONLY AROUND 1-2 PM CDT WAS SIGNIFICANT DISSIPATION OF THE FOG LAYER EVIDENT ON SATELLITE. SOME LINGERING PATCHY DENSE FOG CONTINUED AT MINOT TO HARVEY/CARRINGTON/RUGBY AT 2 PM. ABOVE THE SURFACE BOUNDARY LAYER THROUGH H850...SIGNIFICANT WARM ADVECTION WAS MOVING IN FROM SOUTHWEST TO NORTHEAST ACROSS THE REGION. HAD EXPECTED THE FOG TO DISSIPATE EARLIER BASED ON THIS...BUT IT WAS DELAYED BY THE SNOW PACK AND COTEAU INFLUENCES MENTIONED ABOVE. AS THE FOG AND LOW CLOUDS DISSIPATE...THE WARM ADVECTION FROM ABOVE THE BOUNDARY LAYER SHOULD BECOME MORE WELL-ESTABLISHED WHICH SHOULD ACT TO KEEP FOG FROM RE-DEVELOPING. HOWEVER...WITH SUNSET APPROACHING TEMPERATURES WILL FALL AND THE THREAT FOR RE-DEVELOPMENT OF FOG OVER THE SNOW PACK RISES. THUS THE PROBLEM FOR TONIGHT IS WHERE/WHEN/HOW DENSE ANY FOG WILL RE-DEVELOP - IN OTHER WORDS WHICH FORCES WILL WIN OUT. THUS REGARDING FOG TONIGHT - HAVE A MENTION OF PATCHY/AREAS/WIDESPREAD FOG MAINLY OVER THE SNOW PACK THROUGH MID MORNING ON FRIDAY. NEXT ATTENTION TURNS TO THE UPPER LEVEL SHORTWAVE TO BRING SOME LIGHT PRECIPITATION TO THE AREA. LATEST SATELLITE IMAGERY INDICATES THE SHORTWAVE IS OVER SOUTHERN ALBERTA/SASKATCHEWAN. THIS SHORTWAVE IS PROGGED TO REACH WESTERN NORTH DAKOTA AROUND MIDNIGHT AND SPREAD EASTWARD ACROSS THE STATE ON FRIDAY. TEMPERATURE PROFILES FROM FORECAST SOUNDINGS INDICATE A STRONG WARM LAYER ALOFT AT H850 MENTIONED ABOVE. THESE FACTORS RESULT IN EXPECTED PRECIPITATION TO BE IN THE FORM OF FREEZING RAIN OR SLEET IN THE NORTHWEST AND FREEZING RAIN SOUTHWEST AFTER MIDNIGHT THROUGH DAYBREAK. PRECIPITATION SPREADS EASTWARD ON FRIDAY...MAINLY IN THE FORM OF RAIN IN THE SOUTHWEST AND FAR SOUTH CENTRAL BY LATE MORNING/AFTERNOON...AND IN THE FORM OF A WINTRY MIX ACROSS THE NORTHWEST AND NORTH CENTRAL. LIGHT AMOUNTS OF ONLY A FEW HUNDREDTHS UP TO A TENTH OF AN INCH ARE EXPECTED. REGARDING TEMPERATURES: LOWS TONIGHT MAINLY IN THE TEENS NORTH AND EAST OF THE MISSOURI RIVER AND IN THE 20S SOUTH AND WEST OF THE RIVER. STRONG WARM ADVECTION ON FRIDAY SHOULD ALLOW THE SNOW FREE AREAS OF THE SOUTHWEST TO WARM INTO THE MID 50S TO LOWER 60S (NOTING THAT HETTINGER HAD REACHED THE LOWER 50S AS OF 2 PM CDT THURSDAY). ACROSS THE SNOWPACK LOOK FOR HIGHS FRIDAY IN THE 30S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 314 PM CDT THU MAR 28 2013 H5 PATTERN PER GFS/ECMWF/GEM ADVERTISE AN UPPER LOW FORECAST TO MOVE FROM THE NORTHWEST TERRITORIES OF CANADA FRIDAY NIGHT INTO THE NORTHERN GREAT LAKES BY EARLY NEXT WEEK. IN DOING SO...A NORTHWESTERLY FLOW ALOFT WILL BECOME FIRMLY ENTRENCHED INTO NORTH DAKOTA FOR THE WEEKEND AND INTO THE EARLY/MIDDLE PART OF NEXT WEEK. A COUPLE OF SHORTWAVES WILL MOVE THROUGH WITH THEIR ASSOCIATED SURFACE FEATURES/COLD FRONTAL PASSAGES...RESULTING IN COLDER AIR FOR THE WEEKEND. THE FIRST COLD FRONT IS FORECAST TO MOVE THROUGH FRIDAY NIGHT WITH A CHANCE OF A WINTRY MIX OF FREEZING RAIN/SLEET/OR RAIN. SATURDAY LOOKS DRY...A BIT COOLER BEHIND THE INITIAL COLD FRONT AS MENTIONED ABOVE. HOWEVER...THE MAIN SURGE OF THE COLDEST AIR WILL MOVE THROUGH SATURDAY NIGHT...AND REMAIN IN WESTERN AND CENTRAL NORTH DAKOTA THROUGH MONDAY MORNING. THIS IS WHEN THE MAIN H85 BAROCLINIC ZONE WITH TEMPERATURES AS COLD AS -16C DOMINATE MOST OF NORTH DAKOTA. WITH THAT BAROCLINIC ZONE PUSHING INTO THE SOUTHWEST...THE INTERACTION OF LOW LEVEL CONVERGENCE AND A 100KT H3 JET STREAK WILL PRODUCE ENOUGH LARGE SCALE ASCENT/H85-H3 OMEGA FOR AN AREA OF SNOW TO DEVELOP LATE SATURDAY NIGHT INTO SUNDAY IN THE SOUTHWEST. UPWARDS OF AROUND ONE INCH IS FORECAST BY SUNDAY EVENING IN THE SOUTHWEST. UPPER LEVEL RIDGING AND ITS ASSOCIATED SURFACE HIGH PRESSURE OF 1037MB WILL FOLLOW FOR MONDAY AND TUESDAY RESULTING IN DRY WEATHER. THE SURFACE HIGH IS FORECAST TO REACH NORTHWEST NORTH DAKOTA MONDAY MORNING PRODUCING THE COLDEST READINGS THERE...THEN SHIFTING INTO THE JAMES RIVER VALLEY BY TUESDAY MORNING. ON THE BACK SIDE OF THE HIGH PRESSURE...EXPECT A BRIEF RETURN OF MILDER AIR AS A LOW LEVEL SOUTHERLY FLOW INITIATES TUESDAY INTO TUESDAY NIGHT. ANOTHER COLD FRONT WHIPS THROUGH WEDNESDAY...HOWEVER PRECIPITATION LOOKS MINIMAL AT THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 845 PM CDT THU MAR 28 2013 LIFR/VLIFR CONDITIONS IN DENSE FOG WILL CONTINUE AT KMOT AND KJMS POSSIBLY THROUGH 17-18 UTC FRIDAY. SIMILIAR CONDITIONS AT KBIS MAY IMPROVE SLIGHTLY FASTER IN THE 15-16 UTC TIME FRAME. AS OF 0530 UTC...KISN WAS ON THE FRINGE OF THE DENSE FOG BANK...AND MAY FALL INTO IFR CONDITIONS BY 08 UTC...AFTER WHICH MID LEVEL CLOUDS SPREAD ACROSS THE AREA AND MAY LIMIT FOG THEREAFTER FOR KISN. WITH WEAK UPSLOPE FLOW THROUGH THE NIGHT...KDIK MAY SEE A CONTINUED TREND TOWARDS MVFR/IFR VISIBILITIES IN FOG. FOR FRIDAY...SCATTERED PRECIPITATION POSSIBLY IN THE FORM OF FREEZING RAIN OR SLEET MAY IMPACT KISN AND KMOT...AND POSSIBLY KJMS FRIDAY EVENING. SCATTERED SHOWERS WITH POSSIBLY AN ISOLATED THUNDERSTORM IS POSSIBLE NEAR KDIK FRIDAY AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR NDZ001>005-009>013-019>023-025-034>037-042-045>048-050-051. && $$ UPDATE...AYD SHORT TERM...JV LONG TERM...KS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1016 PM EDT SAT MAR 30 2013 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OF THE REGION TONIGHT. A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY ON SUNDAY...PROVIDING A CHANCE OF RAIN. A COLD FRONT WILL THEN MOVE THROUGH SUNDAY NIGHT...PROVIDING COOLER TEMPERATURES FOR THE FIRST PART OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... PCPN IS BEGINNING TO FORM IN SOUTH CENTRAL KY IN RESPONSE TO THE H5 S/W THAT IS WORKING UP THE OHIO VALLEY. 18Z LOW DEVELOPED A MORE DEFINED SFC LOW AND MOVED IT ACROSS THE FA OVERNIGHT. THE 00Z NAM IS A LITTLE LESS DEVELOPED PUT STILL PUSHES THE BEST PCPN ACROSS THE SE QUARTER OF THE FA BETWEEN 06Z-12Z. THE PREVIOUS FORECAST HAD THIS SCENARIO...SO ONLY ADJUSTED THE TIMING A LITTLE AT THE BEGINNING. TEMPERATURES IN THE E COOLED OFF QUICKLY THIS EVENING WITH THE DRY DEWPOINTS AND MIGHT DROP A FEW MORE DEGREES BEFORE STARTING TO RISE TOWARDS MORNING. OVERALL KEPT THE LOWS IN THE PREVIOUS FORECAST RANGES. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... A SHORTWAVE CURRENTLY MOVING THROUGH THE MIDDLE MISSISSIPPI VALLEY WILL BEGIN TO AFFECT THE WESTERN CWA BY 06Z. THE AMPLITUDE OF THIS SHORTWAVE IS NOT ESPECIALLY STRONG...AND IT IS SOMEWHAT TOUGH TO DISCERN WHEN LOOKING ONLY AT 500MB HEIGHT CONTOURS. WITH THE DRY AIR IN PLACE OVER MUCH OF THE OHIO VALLEY RIGHT NOW...IT IS NOT ENTIRELY SURPRISING THAT THE TREND HAS BEEN TOWARD SLIGHTLY DRIER SOLUTIONS FOR SUNDAY MORNING. THE SIGNAL FROM THE HIGH- RESOLUTION OUTPUT IS CONFLICTING...WITH THE 12Z SPC-WRF INDICATING ONLY SCATTERED SHOWERS (AND SOME BIG DRY PATCHES)...AND THE MOST RECENT HRRR RUN SHOWING A SOLID AREA OF PRECIPITATION FOR THE SOUTHERN HALF OF THE CWA. TIMING WAS ADJUSTED ON THE POPS...WITH A SLIGHTLY ADJUSTMENT DOWNWARD IN VALUE AS WELL...AND NO HIGHER THAN LIKELY FOR THE SOUTHERN CWA. AN ASPECT OF THE SYSTEM THAT IS AGREED UPON FROM ALL SOURCES IS A SPLIT IN THE PRECIPITATION BETWEEN A SOUTHERN AREA OF PRECIPITATION (PRIMARILY AFFECTING KENTUCKY AND TENNESSEE) AND WITH A NORTHERN STREAM SYSTEM MOVING THROUGH MICHIGAN. THE NORTHERN SYSTEM WILL LAG BEHIND THE SOUTHERN SYSTEM BY SEVERAL HOURS...BUT THIS WILL LIKELY ACT TO INITIATE MORE SHOWERS OVER THE EASTERN CWA THROUGH MID-AFTERNOON. SPC SREF PARAMETERS INDICATE THAT SOME WEAK INSTABILITY COULD BUILD IN TO THE SOUTHEASTERN AND EASTERN CWA DURING THIS TIME FRAME...SO THUNDER WAS KEPT IN THE FORECAST. BY SUNDAY NIGHT...A COLD FRONT WILL BE MOVING INTO THE NORTHERN PORTIONS OF THE CWA. WHILE THE COLD ADVECTION IS NOTABLE BEHIND THE FRONT...THE SURFACE PRESSURE PATTERN IS WEAK...AND FORCING IS ALMOST NON-EXISTENT. AS A RESULT OF THIS...THE FRONT SHOULD PASS THROUGH DRY. HOWEVER...IN A REGION OF COLD ADVECTION BEHIND THE FRONT...A WEAK RIPPLE IN THE FLOW (ROUNDING THE SOUTHWESTERN EDGE OF THE LARGE UPPER TROUGH) WILL PASS INTO THE CWA. THIS FEATURE MAY BRING A BAND OF LIGHT PRECIPITATION DURING THE FIRST TWO-THIRDS OF MONDAY. HOWEVER...THIS HAS BEEN MODELED DRIER ON THE LAST SET OF RUNS...SO POPS HAVE BEEN LIMITED TO 20 PERCENT. TEMPERATURES SUPPORT A MIX OF SNOW AND RAIN (WITH GENERALLY SNOW IN THE NORTH AND GENERALLY RAIN IN THE SOUTH)...BUT AS QPF IS EXTREMELY LIGHT...THE DAY SHOULD NOT BE A STRIKEOUT. WITH THE ONLY SIGNIFICANT TEMPERATURE ADVECTION OCCURRING SUNDAY NIGHT WITH THE COLD FRONT...TEMPS SHOULD REMAIN GENERALLY DIURNAL THROUGH THE PERIOD. AFTER A DAY OF COLD ADVECTION AND AS SKIES CLEAR OUT MONDAY NIGHT...TEMPS APPEAR TO BE SET TO DROP INTO THE 20S...10-15 DEGREES BELOW NORMAL FOR EARLY APRIL. && .LONG TERM /TUESDAY THROUGH SATURDAY/... DEEP MID LVL TROUGH WILL PROGRESS EASTWARD TUESDAY INTO WEDNESDAY ALLOWING SFC HIGH PRESSURE TO SETTLE INTO THE GREAT LAKES AND OHIO VALLEY. ON TUESDAY...THERE COULD BE SOME DIURNALLY DRIVEN CUMULUS BUT IT LOOKS LIKE MOST OF THE REGION WILL BE MOSTLY SUNNY. IT SHOULD BE MOSTLY CLEAR TUESDAY NIGHT AND MOSTLY SUNNY ON WEDNESDAY. COLDEST TEMPERATURES ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. HIGHS ON TUESDAY WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH. LOWS TUESDAY NIGHT WILL DROP INTO THE LOWER AND MID 20S. SOME MODIFICATION IS EXPECTED ON WEDNESDAY BUT TEMPERATURES WILL REMAIN BELOW NORMAL FOR EARLY APRIL. HIGHS WILL RANGE FROM THE LOWER 40S NE TO THE UPPER 40S SOUTHWEST. UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN LATE IN THE WEEK. THERE WILL BE A SPLIT FLOW BETWEEN NRN STREAM ENERGY AND SRN STREAM ENERGY. MODELS HAVE BEEN OSCILLATING ON HOW THE NRN STREAM ENERGY WILL INTERACT WITH THE SRN STREAM ENERGY. FOR NOW...HAVE KEPT AN UPR LVL LOW AND PCPN WITH THE SRN STREAM ENERGY TO OUR SOUTH AND EAST THURSDAY INTO FRIDAY WHILE A WEAK COLD FRONT DROPS SOUTHEAST THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO MODERATE WITH HIGHS IN THE 50S ON THURSDAY AND 50S TO NEAR 60 ON FRIDAY. FOR FRIDAY NIGHT INTO SATURDAY...SURFACE HIGH PRESSURE WILL PUSH INTO THE REGION AND WILL EVENTUALLY MOVE EAST. DRY WEATHER WITH TEMPERATURES NEAR SEASONAL NORMALS ARE EXPECTED. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... H5 S/W SWINGS UP THE OH VALLEY THIS EVENING AND INTO THE TAFS AFT 06Z. BEST LIFT WILL BE ACROSS KY WITH THIS INITIAL SHOT AS A WEAK SFC LOW DEVELOPS IN KY...THUS AFFECTING CVG/LUK WITH THE BEST CHANCE OF PCPN AND MVFR CONDITIONS. AS LOW WORKS E BETWEEN 06Z-12Z SHRA DEVELOP ACROSS SRN OH...LEAVING ILN/CMH/LCK ON THE FRINGE OF THE PCPN SHIELD. NOT SEEING MUCH IN THE WAY OF INSTABILITY EITHER SURFACE OR ALOFT WITH THIS INITIAL SHOT SO REMOVED MENTION OF THUNDER. AS INITIAL SFC TROF SWINGS THRU AROUND 12Z SOME ADDITIONAL SHOWERS COULD DEVELOP...SO KEPT A MENTION OF VCSH DURING THE MORNING HOURS. SECONDARY TROF THIN WORK THROUGH AROUND 18Z SCATTERING THINGS OUT AND PUSHING THE SHRA E. WINDS PICK UP AS THEY TURN TO THE W BEHIND THIS TROF. SOME CAPE DEVELOPS INT HE AFTN...BUT WILL PCPN SHOULD BE SHUNTED E BEFORE THIS CAN BE REALIZED AS THUNDER. OUTLOOK...MVFR POSSIBLE ON MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...SITES SHORT TERM...HATZOS LONG TERM...HICKMAN AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
811 PM EDT SAT MAR 30 2013 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OF THE REGION TONIGHT. A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY ON SUNDAY...PROVIDING A CHANCE OF RAIN. A COLD FRONT WILL THEN MOVE THROUGH SUNDAY NIGHT...PROVIDING COOLER TEMPERATURES FOR THE FIRST PART OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A RELATIVELY DRY SURFACE AIR MASS HAS INHIBITED CUMULUS DEVELOPMENT TODAY. A LOOK AT SURFACE OBS SHOWS THAT DEWPOINTS OVER THE REGION REMAIN IN THE 20S TO LOWER 30S...WITH DEWPOINTS OVER 40 SOUTH AND WEST OF A BOUNDARY THAT CUTS THROUGH THE FAR SOUTHWESTERN TIP OF INDIANA. AT THE SAME TIME...HIGH CLOUDS HAVE BEEN INCREASING...AND MOISTURE IS EXPECTED TO CONTINUE TO LOWER THROUGH THE NEAR TERM OF THE FORECAST. THE FOCUS FOR PRECIPITATION WILL BE ON A SHORTWAVE CURRENTLY MOVING ACROSS MISSOURI AND INTO ILLINOIS. THERE WILL BE EFFECTS ON THE CWA BEFORE MORNING...BUT FOR THE SAKE OF EASE...THIS FEATURE WILL BE DISCUSSED IN THE SHORT TERM SECTION OF THE AFD. WITH CLOUDS MOVING IN...AND WARM ADVECTION AHEAD OF THE SHORTWAVE...OVERNIGHT TEMPS WILL BE AT LEAST TEN DEGREES WARMER THAN LAST NIGHT. MIN TEMP VALUES ARE NEAR OR SLIGHTLY WARMER THAN THE MODEL BLEND...WHICH EXHIBITS A RELATIVELY SMALL SPREAD. HOWEVER...THE FORECAST IS NOT AS WARM AS THE RAP13. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... A SHORTWAVE CURRENTLY MOVING THROUGH THE MIDDLE MISSISSIPPI VALLEY WILL BEGIN TO AFFECT THE WESTERN CWA BY 06Z. THE AMPLITUDE OF THIS SHORTWAVE IS NOT ESPECIALLY STRONG...AND IT IS SOMEWHAT TOUGH TO DISCERN WHEN LOOKING ONLY AT 500MB HEIGHT CONTOURS. WITH THE DRY AIR IN PLACE OVER MUCH OF THE OHIO VALLEY RIGHT NOW...IT IS NOT ENTIRELY SURPRISING THAT THE TREND HAS BEEN TOWARD SLIGHTLY DRIER SOLUTIONS FOR SUNDAY MORNING. THE SIGNAL FROM THE HIGH- RESOLUTION OUTPUT IS CONFLICTING...WITH THE 12Z SPC-WRF INDICATING ONLY SCATTERED SHOWERS (AND SOME BIG DRY PATCHES)...AND THE MOST RECENT HRRR RUN SHOWING A SOLID AREA OF PRECIPITATION FOR THE SOUTHERN HALF OF THE CWA. TIMING WAS ADJUSTED ON THE POPS...WITH A SLIGHTLY ADJUSTMENT DOWNWARD IN VALUE AS WELL...AND NO HIGHER THAN LIKELY FOR THE SOUTHERN CWA. AN ASPECT OF THE SYSTEM THAT IS AGREED UPON FROM ALL SOURCES IS A SPLIT IN THE PRECIPITATION BETWEEN A SOUTHERN AREA OF PRECIPITATION (PRIMARILY AFFECTING KENTUCKY AND TENNESSEE) AND WITH A NORTHERN STREAM SYSTEM MOVING THROUGH MICHIGAN. THE NORTHERN SYSTEM WILL LAG BEHIND THE SOUTHERN SYSTEM BY SEVERAL HOURS...BUT THIS WILL LIKELY ACT TO INITIATE MORE SHOWERS OVER THE EASTERN CWA THROUGH MID-AFTERNOON. SPC SREF PARAMETERS INDICATE THAT SOME WEAK INSTABILITY COULD BUILD IN TO THE SOUTHEASTERN AND EASTERN CWA DURING THIS TIME FRAME...SO THUNDER WAS KEPT IN THE FORECAST. BY SUNDAY NIGHT...A COLD FRONT WILL BE MOVING INTO THE NORTHERN PORTIONS OF THE CWA. WHILE THE COLD ADVECTION IS NOTABLE BEHIND THE FRONT...THE SURFACE PRESSURE PATTERN IS WEAK...AND FORCING IS ALMOST NON-EXISTENT. AS A RESULT OF THIS...THE FRONT SHOULD PASS THROUGH DRY. HOWEVER...IN A REGION OF COLD ADVECTION BEHIND THE FRONT...A WEAK RIPPLE IN THE FLOW (ROUNDING THE SOUTHWESTERN EDGE OF THE LARGE UPPER TROUGH) WILL PASS INTO THE CWA. THIS FEATURE MAY BRING A BAND OF LIGHT PRECIPITATION DURING THE FIRST TWO-THIRDS OF MONDAY. HOWEVER...THIS HAS BEEN MODELED DRIER ON THE LAST SET OF RUNS...SO POPS HAVE BEEN LIMITED TO 20 PERCENT. TEMPERATURES SUPPORT A MIX OF SNOW AND RAIN (WITH GENERALLY SNOW IN THE NORTH AND GENERALLY RAIN IN THE SOUTH)...BUT AS QPF IS EXTREMELY LIGHT...THE DAY SHOULD NOT BE A STRIKEOUT. WITH THE ONLY SIGNIFICANT TEMPERATURE ADVECTION OCCURRING SUNDAY NIGHT WITH THE COLD FRONT...TEMPS SHOULD REMAIN GENERALLY DIURNAL THROUGH THE PERIOD. AFTER A DAY OF COLD ADVECTION AND AS SKIES CLEAR OUT MONDAY NIGHT...TEMPS APPEAR TO BE SET TO DROP INTO THE 20S...10-15 DEGREES BELOW NORMAL FOR EARLY APRIL. && .LONG TERM /TUESDAY THROUGH SATURDAY/... DEEP MID LVL TROUGH WILL PROGRESS EASTWARD TUESDAY INTO WEDNESDAY ALLOWING SFC HIGH PRESSURE TO SETTLE INTO THE GREAT LAKES AND OHIO VALLEY. ON TUESDAY...THERE COULD BE SOME DIURNALLY DRIVEN CUMULUS BUT IT LOOKS LIKE MOST OF THE REGION WILL BE MOSTLY SUNNY. IT SHOULD BE MOSTLY CLEAR TUESDAY NIGHT AND MOSTLY SUNNY ON WEDNESDAY. COLDEST TEMPERATURES ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. HIGHS ON TUESDAY WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH. LOWS TUESDAY NIGHT WILL DROP INTO THE LOWER AND MID 20S. SOME MODIFICATION IS EXPECTED ON WEDNESDAY BUT TEMPERATURES WILL REMAIN BELOW NORMAL FOR EARLY APRIL. HIGHS WILL RANGE FROM THE LOWER 40S NE TO THE UPPER 40S SOUTHWEST. UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN LATE IN THE WEEK. THERE WILL BE A SPLIT FLOW BETWEEN NRN STREAM ENERGY AND SRN STREAM ENERGY. MODELS HAVE BEEN OSCILLATING ON HOW THE NRN STREAM ENERGY WILL INTERACT WITH THE SRN STREAM ENERGY. FOR NOW...HAVE KEPT AN UPR LVL LOW AND PCPN WITH THE SRN STREAM ENERGY TO OUR SOUTH AND EAST THURSDAY INTO FRIDAY WHILE A WEAK COLD FRONT DROPS SOUTHEAST THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO MODERATE WITH HIGHS IN THE 50S ON THURSDAY AND 50S TO NEAR 60 ON FRIDAY. FOR FRIDAY NIGHT INTO SATURDAY...SURFACE HIGH PRESSURE WILL PUSH INTO THE REGION AND WILL EVENTUALLY MOVE EAST. DRY WEATHER WITH TEMPERATURES NEAR SEASONAL NORMALS ARE EXPECTED. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... H5 S/W SWINGS UP THE OH VALLEY THIS EVENING AND INTO THE TAFS AFT 06Z. BEST LIFT WILL BE ACROSS KY WITH THIS INITIAL SHOT AS A WEAK SFC LOW DEVELOPS IN KY...THUS AFFECTING CVG/LUK WITH THE BEST CHANCE OF PCPN AND MVFR CONDITIONS. AS LOW WORKS E BETWEEN 06Z-12Z SHRA DEVELOP ACROSS SRN OH...LEAVING ILN/CMH/LCK ON THE FRINGE OF THE PCPN SHIELD. NOT SEEING MUCH IN THE WAY OF INSTABILITY EITHER SURFACE OR ALOFT WITH THIS INITIAL SHOT SO REMOVED MENTION OF THUNDER. AS INITIAL SFC TROF SWINGS THRU AROUND 12Z SOME ADDITIONAL SHOWERS COULD DEVELOP...SO KEPT A MENTION OF VCSH DURING THE MORNING HOURS. SECONDARY TROF THIN WORK THROUGH AROUND 18Z SCATTERING THINGS OUT AND PUSHING THE SHRA E. WINDS PICK UP AS THEY TURN TO THE W BEHIND THIS TROF. SOME CAPE DEVELOPS INT HE AFTN...BUT WILL PCPN SHOULD BE SHUNTED E BEFORE THIS CAN BE REALIZED AS THUNDER. OUTLOOK...MVFR POSSIBLE ON MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...HICKMAN AVIATION...SITES
AREA FORECAST DISCUSSION
NWS TULSA OK
1150 PM CDT THU MAR 28 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. VFR CONDITIONS ARE THE NORM ACROSS THE AREA AT THIS TIME..THAT IS EXPECTED TO CHANGE SOME AS WE MOVE INTO FRIDAY MORNING WITH MVFR CONDITIONS DEVELOPING DUE TO CEILINGS AND SCATTERED SHOWERS AND THUNDERSTORMS. CONDITIONS WILL IMPROVE SOME LATE FRIDAY MORNING/EARLY AFTERNOON BEFORE MORE SHOWERS AND THUNDERSTORMS MOVE INTO THE AREA. && .PREV DISCUSSION... /ISSUED 910 PM CDT THU MAR 28 2013/ UPDATE... FORECAST WAS UPDATED TO REDUCE POPS THIS EVENING BASED ON LATEST DATA. SEE DISCUSSION BELOW. DISCUSSION... THE LATEST DATA FROM THE HRRR AND NEW 00Z NAM SUGGEST THAT THE ACTIVITY WILL BE SLOWER TO GET GOING TONIGHT...AND THUS POPS WERE REDUCED THRU 06Z. POPS AFT 06Z LOOK GOOD...AND ARE A GOOD COMPROMISE BETWEEN THE HRRR AND NAM SOLUTIONS. ISENTROPIC CHARTS EXPLAIN WHY THE ACTIVITY WILL BE SLOWER TO GET GOING...WITH LITTLE IN THE WAY OF ASCENT FORECAST THRU 06Z. BY 06Z AND AFTER...THE 295K SHOWS SOME LIFT AND GOOD MOISTURE TRANSPORT AIMED AT THE OZARK REGION. THERE IS STILL A LIMITED RISK OF AN ISOLATED SEVERE HAIL STORM WITH POTENTIAL FOR UP TO HALF DOLLAR SIZE GIVEN SUFFICIENT SHEAR AND INCREASING ELEVATED INSTABILITY ACROSS EASTERN OKLAHOMA AFT MIDNIGHT. LACY PREV DISCUSSION... /ISSUED 630 PM CDT THU MAR 28 2013/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. CONDITIONS WILL DETERIORATE TONIGHT WITH MVFR CONDITIONS DEVELOPING AFTER MIDNIGHT AND CONTINUING THROUGH FRIDAY MORNING. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO AFFECT AREA TAFS LATE TONIGHT INTO FRIDAY MORNING WITH SOME REDEVELOPED EXPECTED LATE FRIDAY AFTERNOON PRIOR TO THE EXPIRATION OF THE CURRENT TAF PERIOD. PREV DISCUSSION... /ISSUED 346 PM CDT THU MAR 28 2013/ DISCUSSION... A NEARLY STATIONARY FRONTAL BOUNDARY WAS POSITIONED FROM THE OKLAHOMA PANHANDLE TO SOUTHEAST KANSAS THIS AFTERNOON. SOUTH OF THE BOUNDARY...TEMPERATURES ARE RUNNING ABOUT 5 TO 10 DEGREES WARMER THAN THIS TIME YESTERDAY WITH HIGH CLOUDS AND SOUTHERLY WINDS BEING COMMON. LOW LEVEL MOISTURE HAS ALSO INCREASED FROM SOUTH TO NORTH ACROSS THE REGION THIS AFTERNOON...LIMITING FIRE WEATHER DANGERS FOR EASTERN OKLAHOMA AND NORTHWEST ARKANSAS. THE FRONTAL BOUNDARY JUST NORTH OF THE CWA WILL BE THE FOCUS FOR CHANCES OF SHOWERS AND THUNDERSTORMS OVER THE NEXT SEVERAL DAYS AS MID LEVEL WAVES PROGRESS THROUGH THE PLAINS WITHIN NORTHWESTERLY UPPER LEVEL FLOW. THE FIRST WAVE IS EXPECTED TO MOVE THROUGH TONIGHT AND FRIDAY...WITH A SECOND WAVE FRIDAY NIGHT AND SATURDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE THIS EVENING ACROSS THE REGION WITH GREATER CHANCES LATE TONIGHT AND FRIDAY ACROSS NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS. CHANCES THEN CONTINUE TO SPREAD SOUTHWARD FRIDAY EVENING AND SATURDAY WITH THE NEXT WAVE. WARM SURFACE TEMPS...STEEP LAPSE RATES AND COLD TEMPERATURES ALOFT DURING THIS TIME FRAME WILL ALLOW FOR INSTABILITY TO DEVELOP OVER THE REGION WHICH COULD ALLOW FOR SOME THUNDERSTORMS TO BECOME STRONG TO SEVERE WITH LARGE HAIL BEING THE MAIN THREAT. THE FRONTAL BOUNDARY IS PROGGED TO PUSH INTO EASTERN OKLAHOMA AND NORTHWEST ARKANSAS SATURDAY NIGHT AS A MORE DEFINED UPPER LEVEL WAVE DROPS SOUTHEAST OUT OF CANADA. THIS WILL CONTINUE CHANCES FOR SHOWERS AND THUNDERSTORMS INTO SUNDAY. LATEST MODEL SOLUTIONS ARE INDICATING THAT THE FRONTAL BOUNDARY COULD HANG UP NEAR THE RED RIVER VALLEY...WHICH WOULD CONTINUE PRECIP CHANCES ACROSS THE SOUTH DURING THE DAY SUNDAY. TEMPERATURES DURING THE DAY SUNDAY LOOK TO REMAIN WARM WITH HIGHS IN THE MID 60S TO LOW 70S POSSIBLE. THE WARM TEMPERATURES WILL BE QUICK TO MOVE OUT SUNDAY NIGHT AND MONDAY AS ANOTHER MORE STRONGER COLD FRONT PUSHES THROUGH THE REGION. CHANCES OF SHOWERS AND THUNDERSTORMS WILL AGAIN SPREAD OVER THE REGION DURING THE DAY MONDAY WITH THE MOVEMENT OF THE FRONT. BEHIND THE FRONT...MUCH COLDER AND DRIER AIR IS EXPECTED TO FILTER IN WITH TEMPERATURES DROPPING DURING THE DAY BEHIND THE FRONT. LOWS TUESDAY MORNING COULD POTENTIALLY REACH CLOSE TO FREEZING NEAR THE KANSAS BORDER. THIS FRONT LOOKS TO PUSH THROUGH THE REGION AND KEEP AN UPPER LEVEL WAVE MOVING OUT OF THE DESERT SOUTHWEST SOUTH OF THE REGION. THIS SHOULD KEEP PRECIP SOUTH OF THE REGION FOR THE MIDDLE PART OF THE WEEK. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...10
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1029 PM CDT SAT MAR 30 2013 .UPDATE... IT IS QUIET ACROSS THE REGION AT THIS TIME BUT ANOTHER COMPLEX OF STORMS IS EXPECTED TO CROSS OUT OF OKLAHOMA AND INTO NORTH TEXAS NEAR DAYBREAK SUNDAY MORNING. BOTH THE LATEST NAM AND OCCASIONAL RUNS OF THE RAP DEVELOP STORMS AROUND AND/OR NORTHEAST OF THE DFW METROPLEX AROUND 4 AM. THE LATEST RUN OF THE RAP DOES NOT HAVE THESE STORMS. AROUND 4 AM...THE MODELS STILL HAVE THE BEST LIFT WEST OF THE REGION BUT SOME WEAK HEIGHT FALLS MAY BE STARTING TO SPREAD EAST AS A SHORTWAVE APPROACHES THE REGION FROM THE WEST. ISENTROPIC LIFT LOOKS TO BE FAIRLY WEAK AT THIS TIME WITH SOME WEAK LIFT ON THE 295K SURFACE. BUFR SOUNDINGS AT THIS TIME SHOW A WELL CAPPED ENVIRONMENT WITH NOT MUCH MOISTURE OR INSTABILITY ABOVE THE CAP. THEREFORE...THINK IT WILL BE DIFFICULT FOR STORMS TO DEVELOP THIS EARLY BUT NOT ENTIRELY IMPOSSIBLE. INSTEAD...THE MAIN FOCUS FOR THE OVERNIGHT PERIOD SHIFTS TO THE COMPLEX OF STORMS OR MCS THAT WILL DEVELOP ALONG THE COLD FRONT IN OKLAHOMA AND MARCH SOUTHEAST INTO NORTH TEXAS. THE BEST TIMING FOR THESE STORMS TO CROSS THE RED RIVER NEAR MONTAGUE AND COOKE COUNTIES IS AROUND 5-6 AM. THEREFORE...TRENDED HIGHEST POPS BACK TO THE WEST SOME AND ALSO TRIMMED ACROSS THE SOUTH SOME DUE TO THE SLIGHTLY SLOWER ARRIVAL TIME. BECAUSE OF THIS SLOWER TIME...ALSO ADJUSTED THE HIGHER POPS SUNDAY MORNING FARTHER NORTH AND WEST. AT THE TIME THE STORMS ARRIVE...THE CAP WILL BE WEAK OR ERODED AND THERE WILL BE A THREAT FOR SEVERE STORMS PRODUCING HAIL AND DAMAGING WINDS. SOME ADDITIONAL DECENT RAINFALL IS ALSO LIKELY WITH THIS STORM SYSTEM...ESPECIALLY OVER THE NORTHERN AND EASTERN COUNTIES. ADDITIONAL STORMS WILL ALSO BE POSSIBLE SUNDAY AFTERNOON ACROSS THE SOUTHERN COUNTIES WHERE THE FRONT WILL BE LOCATED IN THE AFTERNOON HOURS. THESE STORMS COULD POTENTIALLY BE SEVERE AS WELL. 82/JLD && .AVIATION... A RELATIVELY QUIET EVENING FOR ALL NORTH TEXAS TERMINALS. CHALLENGES INCLUDE TIMING OF MVFR CIGS AFTER MIDNIGHT AND STORMS BY DAYBREAK SUNDAY AND AFTER WITH THE ARRIVAL OF A COLD FRONT. ISOLATED STRONG TO SEVERE STORMS ARE DEVELOPING TO THE WEST ON THE DRYLINE AND NORTHWEST OFF A WEAK SURFACE BOUNDARY ACROSS SOUTHWEST OKLAHOMA. MEAN STEERING CURRENTS WILL MOVE THIS ACTIVITY SOUTHEAST WITH TIME...HOWEVER WE EXPECT A DIMINISHING TREND AFTER NIGHTFALL AS WE AWAIT THE BETTER FORCING WITH A SHORTWAVE AND COLD FRONT LATE TONIGHT AND SUNDAY MORNING. VFR WILL PREVAIL THROUGH THE EVENING HOURS WITH SOUTHEAST WINDS AROUND 10 KTS. THE COLD FRONT OVER NORTHERN OKLAHOMA BEGINS MOVING SOUTH AFTER MIDNIGHT WITH THE SUPPORT FROM A SHORTWAVE MOVING OUT OF THE SOUTHERN ROCKIES. MVFR CIGS WILL DEVELOP JUST AHEAD OF THE COLD FRONT AS WINDS WEAKEN AND THE BOUNDARY LAYER COOLS. CHANCES FOR SHOWERS AND STORMS WILL INCREASE AT METRO AIRPORTS AROUND SUNRISE AND LAST THROUGH MID MORNING...WHILE ARRIVING MORE TOWARD MIDDAY OR AFTER AT WACO AS THE COLD FRONT MOVES INTO THE AREA. WINDS MAY VEER BRIEFLY SOUTHWEST AROUND 10 KTS JUST AHEAD OF THE COLD FRONT... BUT SHIFT TO THE NORTH AT 10 TO 15 KTS BEHIND IT BY LATE MORNING AT DFW AND IN THE EARLY AFTERNOON AT WACO. CIGS WILL SLOWLY RISE DURING THE AFTERNOON BACK INTO THE VFR CATEGORY. BY EVENING...WINDS VEER NORTHEAST AT 5-10 KTS...AS SURFACE HIGH PRESSURE SETTLES IN FROM THE NORTH. 05/ && .PREV UPDATE... .UPDATE... HAVE CANCELLED THE SEVERE THUNDERSTORM WATCH FOR THE NORTHERN PORTIONS OF THE AREA. STORMS IN THE SOUTHWESTERN COUNTIES CONTINUE TO WEAKEN WITH THE LOST OF HEATING AND WILL NOW SHIFT TO ASSESS THE RAIN AND SEVERE WEATHER THREAT OVERNIGHT. 82/JLD && .PREV DISCUSSION... /ISSUED 351 PM CDT SAT MAR 30 2013/ SOMEWHAT OF A COMPLEX SURFACE PATTERN IN PLACE ACROSS THE SOUTHERN PLAINS THIS AFTERNOON WHICH WILL AFFECT WHICH AREAS SEE THUNDERSTORMS OVER THE NEXT 12 HOURS. A BROAD SURFACE LOW PERSISTS ACROSS FAR WEST TEXAS NEAR LUBBOCK WITH WHAT HAS BEEN A QUASI STATIONARY FRONTAL BOUNDARY EXTENDING TO THE NORTHEAST INTO SOUTHERN KANSAS. THIS ELONGATED TROUGH WILL BECOME A WELL DEFINED COLD FRONT BY LATE TONIGHT AND BEGIN TO MOVE SOUTH INTO THE RED RIVER VALLEY. MEANWHILE A WELL DEFINED WARM SECTOR EXISTS FROM NEAR SAN ANGELO NORTHWARD TO NEAR OKLAHOMA CITY AND BACK SOUTHEAST INTO THE ARKLATEX. THERE IS ALSO ONE DISTINCT OUTFLOW BOUNDARY WHICH IS NOW ALSO MOVING INTO THE ARKLATEX WITH SCATTERED THUNDERSTORMS DEVELOPING ALONG IT. 20Z OBJECTIVE ANALYSIS INDICATES A MODERATELY UNSTABLE AIRMASS IN PLACE ACROSS NORTH TEXAS WITH SURFACE BASED CAPE AROUND 1500J/KG AND LITTLE CONVECTIVE INHIBITION REMAINING ESPECIALLY ACROSS THE EASTERN HALF OF THE CWA. TWO AMDAR VAPOR SOUNDINGS HOWEVER JUST CAME IN ABOUT 20 MINUTES AGO FROM DFW AIRPORT AND REVEALED THAT SUFFICIENT CONVECTIVE INHIBITION REMAINS IN PLACE. THE FLIGHT PATHS CAME IN FROM THE EAST WHERE THE CAP WAS OBSERVED SO THIS YIELDS HIGHER CONFIDENCE THAT CAPPING REMAINS IN PLACE FARTHER EAST THAN INDICATED BY OBJECTIVE ANALYSIS. A VEERED LOW LEVEL WIND PROFILE IS ALSO REINFORCING A WARM LAYER ALOFT ESPECIALLY ACROSS THE WESTERN COUNTIES THIS AFTERNOON. SO WHAT HAPPENS... WITH THE LACK OF ANY APPRECIABLE LARGE SCALE FORCING FOR ASCENT IN THE NEXT 6 HOURS IT APPEARS UNLIKELY THAT THUNDERSTORMS WILL DEVELOP ACROSS NORTH TEXAS THROUGH THIS EVENING. MESOSCALE FORCING ALONG THE OUTFLOW BOUNDARY TO THE EAST IS MORE THAN SUFFICIENT FOR THUNDERSTORM DEVELOPMENT TO CONTINUE IN THE ARKLATEX...AND WILL HAVE SOME 20 POPS ACROSS THE FAR NORTHEAST TO ACCOUNT FOR THIS. OTHERWISE...IT APPEARS THAT WE WILL HAVE TO WAIT UNTIL LATER TONIGHT FOR ADDITIONAL THUNDERSTORMS TO AFFECT THE AREA. THE ONE CAVEAT TO THIS IS THE FAR WESTERN COUNTIES. THE HIGH RES GUIDANCE AND TO A LESSER EXTENT THE GFS/NAM ALL APPEAR TO ATTEMPT TO CONVECT BY 00Z THIS EVENING. THIS APPEARS TO BE IN RESPONSE TO SURFACE HEATING WITH FORCING ALONG THE DRYLINE. CONFIDENCE IN THIS SCENARIO IS LOW NOW GIVEN THE VEERED LOW LEVEL WIND FIELDS AND A LACK OF SUBSTANTIAL CONVERGENCE. AFTER 00Z IT APPEARS THAT THE SURFACE WINDS MAY BACK MORE IN RESPONSE TO UPSTREAM HEIGHT FALLS. THIS COULD LOCALLY ENHANCE CONVERGENCE ACROSS THE WESTERN COUNTIES. IF ANYTHING WERE TO DEVELOP IN THIS AREA IT WOULD LIKELY BE SEVERE. THE MORE LIKELY SCENARIO FOR THUNDERSTORMS TONIGHT APPEARS TO BE IN RESPONSE TO INCREASING FORCING FOR ASCENT AS A SHORTWAVE MOVES THROUGH THE CENTRAL PLAINS AND HEIGHT FALLS OVERSPREAD THE REGION. THE COLD FRONT ACROSS OKLAHOMA WILL BEGIN TO MOVE SOUTH AND SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG IT. ADDITIONAL THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT EARLIER IN THE NIGHT ALONG A PRE-FRONTAL TROUGH WHERE CAPPING GETS SUFFICIENTLY WEAKENED IN RESPONSE TO INCREASING LIFT. ALL OF THIS IS LIKELY TO INITIATE ACROSS SOUTHERN OKLAHOMA AND MOVE SOUTH ACROSS THE RED RIVER. THE BEST TIMING FOR THE INITIAL CONVECTIVE DEVELOPMENT...IF IT CAN DEVELOP...APPEARS TO BE AROUND MIDNIGHT. IF CONVECTION FAILS TO INITIATE ALONG THIS PRE-FRONTAL TROUGH THEN THE MAIN SHOW SHOULD BE ALONG THE FRONT VERY LATE TONIGHT INTO EARLY SUNDAY MORNING. THE ATMOSPHERE REMAINS MODERATELY UNSTABLE WITH VERY STEEP LAPSE RATES SO THUNDERSTORMS WILL HAVE THE POTENTIAL TO BE SEVERE. IF THE EARLIER ROUND OF STORMS CAN DEVELOP...ITS SEVERE POTENTIAL WILL BE GREATER AS IT WILL HAVE AN UNTAPPED RESERVOIR OF INSTABILITY TO WORK WITH. IT IS LIKELY THAT THUNDERSTORMS THAT DEVELOP THAT LATE IN THE NIGHT WILL BE SLIGHTLY ELEVATED...HOWEVER WITH 1500-2000J/KG OF MUCAPE AND 40-50KTS OF DEEP LAYER SHEAR TO WORK WITH...ELEVATED SUPERCELLS ARE LIKELY. LARGE HAIL WILL BE THE MAIN THREAT...ALTHOUGH DAMAGING WINDS CAN EASILY MAKE IT TO THE GROUND DESPITE BEING SLIGHTLY ELEVATED. WILL HAVE POPS INCREASING THROUGH THE NIGHT TONIGHT WITH HIGHEST NUMBERS ALONG THE RED RIVER AND NORTHEAST COUNTIES. ONE OR MORE CLUSTERS OF THUNDERSTORMS SHOULD BE ONGOING EARLY EASTER MORNING ACROSS NORTH TEXAS. AS THE FRONT CONTINUES TO MOVE SOUTH THE THUNDERSTORMS WILL GRADUALLY SHIFT SOUTH AS WELL THROUGH THE DAY. BY AFTERNOON...THE ATMOSPHERE ACROSS THE SOUTHERN HALF OF THE CWA WILL BE UNSTABLE AND SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS THE SOUTHERN COUNTIES. THESE WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL AND DAMAGING WINDS. MONDAY APPEARS TO PROVIDE A BRIEF RESPITE FROM THE ACTIVE WEATHER WITH THE OLD FRONTAL BOUNDARY TO THE SOUTH AND WEAK RIDGING ALOFT. THE BREAK IS EXPECTED TO BE SHORT THOUGH AS A STRONG UPPER LOW MOVES INTO THE 4-CORNERS REGION. THE STRONGER FRONT ASSOCIATED WITH THIS SYSTEM WILL SLIDE SOUTH WITH STRONG ISENTROPIC ASCENT COMMENCING MONDAY NIGHT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED LATE MONDAY NIGHT. BETTER RAIN CHANCES ACROSS NORTH TEXAS WILL BE TUESDAY AND ESPECIALLY TUESDAY NIGHT AS THE LOW SLOWLY MOVES EAST. WILL HAVE HIGH POPS ACROSS THE ENTIRE CWA AS IT APPEARS VERY BENEFICIAL RAINFALL WILL OCCUR ACROSS THE REGION. THUNDERSTORM ACTIVITY IS EXPECTED TO BE ELEVATED AND MORE ISOLATED IN NATURE DURING THIS TIME...SO WIDESPREAD SEVERE WEATHER IS NOT EXPECTED AT THIS TIME. DID WARM TEMPS UP A BIT THROUGH MIDWEEK AS GUIDANCE IS NOT QUITE AS COLD WITH THE AIR COMING DOWN. IT WILL STILL BE CHILLY WITH HIGHS IN THE UPPER 50S AND LOWER 60S. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 62 74 53 76 54 / 50 70 10 10 40 WACO, TX 65 76 58 77 59 / 20 60 20 10 40 PARIS, TX 58 72 52 75 47 / 60 80 10 10 20 DENTON, TX 61 74 53 77 50 / 60 70 10 10 50 MCKINNEY, TX 61 73 53 75 52 / 60 80 10 10 40 DALLAS, TX 64 76 55 78 56 / 50 70 20 10 40 TERRELL, TX 63 74 54 76 56 / 50 80 20 10 30 CORSICANA, TX 63 76 58 77 59 / 20 70 20 10 30 TEMPLE, TX 64 78 58 79 61 / 20 60 20 10 30 MINERAL WELLS, TX 60 75 53 79 52 / 40 50 10 10 50 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/82
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1240 PM CDT FRI MAR 29 2013 .AVIATION... A PERIOD OF UNSETTLED WEATHER IS EXPECTED THE NEXT 24-30 HOURS FOR ALL NORTH TEXAS TAF SITES. AN UPPER LEVEL DISTURBANCE WILL BE MOVING ACROSS THE REGION TONIGHT AND WILL PRODUCE SCATTERED TO CLUSTERS OF CONVECTION THAT BEGIN TO THE WEST AND TRACK EAST ACROSS THE METROPLEX TONIGHT /04-09 UTC /. HAVE ADDED A TEMPO GROUP FOR TSRA/BKN018CB 05-08 UTC. THERE IS ALSO THE POTENTIAL FOR A FEW STORMS TO BE MARGINALLY SEVERE OR SEVERE. IF THIS PANS OUT...THEN THE SEVERE WEATHER THREAT WILL BE MAINLY LARGE HAIL /ONE INCH TO TWO INCHES/ AND A LESSER THREAT OF DAMAGING WINDS. KACT SHOULD ESCAPE THIS EVENT BUT SHOULD SEE VCSH OVERNIGHT. CIGS ARE LIFTING AND EXPECT VFR SKIES THE REST OF THE AFTERNOON. MVFR CIGS WILL RETURN TONIGHT AFTER 03 UTC AND LAST THROUGH MID SUNDAY MORNING BEFORE IMPROVING. ALL SITES HAVE THE POTENTIAL TO SEE BRIEF IFR CONDITIONS 11-14 UTC SUNDAY AFTER THE CONVECTION MOVES EAST OF THE TAF SITES...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THIS CYCLE. WINDS WILL REMAIN SOUTHERLY 13-18KTS TODAY AND SUNDAY...AND 10-15KTS TONIGHT. 75 && .UPDATE... CURRENT FORECAST THROUGH THIS AFTERNOON IS IN GOOD SHAPE AND WILL ONLY MAKE SOME MINOR ADJUSTMENTS TO THE HOURLY GRIDDED DATA. SURFACE ANALYSIS INDICATES A WEAK LOW PRESSURE CENTER ACROSS THE TEXAS PANHANDLE THIS MORNING WITH A STATIONARY FRONTAL BOUNDARY EXTENDING EASTWARD ACROSS CENTRAL OKLAHOMA. STRONG LOW LEVEL WARM ADVECTION HAS AIDED IN A CLUSTER OF SHOWERS AND ELEVATED THUNDERSTORMS ACROSS CENTRAL OKLAHOMA. THESE SHOULD PRIMARILY CONTINUE TO MOVE EAST/SOUTHEAST THROUGH THE DAY WITH A GENERAL WEAKENING TREND AS LOW LEVEL FLOW BACKS AND WEAKENS OVER THE NEXT SEVERAL HOURS. FARTHER SOUTH...SOME SHOWERS ARE APPROACHING THE NORTHWEST COUNTIES. THIS ACTIVITY SHOULD REMAIN IN THE FORM OF SHOWERS AS A STRONG CAPPING INVERSION IS PRESENT ACROSS NORTH TEXAS AT THE PRESENT TIME. FOCUS QUICKLY TURNS TO AN APPROACHING MID LEVEL DISTURBANCE CURRENTLY ENTERING NEW MEXICO. THIS FEATURE INITIALLY WAS NOT SAMPLED WELL BY THE GUIDANCE AS IT WAS OFF THE COAST OF BAJA CALIFORNIA. IT SHOWED UP BETTER IN THE 12Z UPPER AIR ANALYSIS AS A MID LEVEL COLD POCKET OVER TUCSON ARIZONA THIS MORNING AND NOW APPEARS TO BE APPROACHING FAR WEST TEXAS. 12Z GUIDANCE APPEARS TO GENERATE SIGNIFICANTLY MORE FORCING FOR ASCENT WITH THIS FEATURE THIS AFTERNOON DURING PEAK HEATING. BY 00Z A DRYLINE SHOULD BE LOCATED ACROSS THE PANHANDLE AS THE STRONGEST FORCING OVERSPREADS IT. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE AFTERNOON/EARLY EVENING IN AN AREA OF MODERATE INSTABILITY WITH VERY STEEP MID LEVEL LAPSE RATES. THIS SCENARIO WOULD SUPPORT A LARGE HAIL AND DAMAGING WIND THREAT MAINLY ACROSS NORTHWEST TEXAS. IT NOW APPEARS THAT AS THIS FORCING SPREADS EAST...CAPPING ACROSS NORTH TEXAS WILL RAPIDLY WEAKEN AND A CLUSTER OF THUNDERSTORMS WILL SPREAD EAST. THE COVERAGE AND INTENSITY DOES REMAIN SOMEWHAT IN QUESTION FARTHER EAST THOUGH DESPITE AN ERODING CAP. STORMS MAY TEND TO BECOME ELEVATED AS THE BOUNDARY LAYER COOLS AFTER SUNSET. WILL BE ASSESSING SOME HIGH RES GUIDANCE THROUGH EARLY AFTERNOON AND WILL LIKELY UP POPS DURING THE OVERNIGHT TIME FRAME ACROSS NORTH TEXAS. DUNN && .PREV DISCUSSION... /ISSUED 350 AM CDT FRI MAR 29 2013/ LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING. THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE 00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330 MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY. WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING. PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY. AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR MARGINALLY SEVERE STORM SUNDAY AFTERNOON. ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST. AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH. NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL LOCATIONS...BUT CHANCES ARE THERE EACH DAY. TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN BE EXPECTED. HAMPSHIRE && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40 WACO, TX 77 61 79 64 79 / 5 20 20 20 40 PARIS, TX 73 58 75 60 74 / 20 50 30 50 40 DENTON, TX 75 61 80 58 75 / 10 30 20 40 40 MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40 DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40 TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40 CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40 TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30 MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 75/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1118 AM CDT FRI MAR 29 2013 .UPDATE... CURRENT FORECAST THROUGH THIS AFTERNOON IS IN GOOD SHAPE AND WILL ONLY MAKE SOME MINOR ADJUSTMENTS TO THE HOURLY GRIDDED DATA. SURFACE ANALYSIS INDICATES A WEAK LOW PRESSURE CENTER ACROSS THE TEXAS PANHANDLE THIS MORNING WITH A STATIONARY FRONTAL BOUNDARY EXTENDING EASTWARD ACROSS CENTRAL OKLAHOMA. STRONG LOW LEVEL WARM ADVECTION HAS AIDED IN A CLUSTER OF SHOWERS AND ELEVATED THUNDERSTORMS ACROSS CENTRAL OKLAHOMA. THESE SHOULD PRIMARILY CONTINUE TO MOVE EAST/SOUTHEAST THROUGH THE DAY WITH A GENERAL WEAKENING TREND AS LOW LEVEL FLOW BACKS AND WEAKENS OVER THE NEXT SEVERAL HOURS. FARTHER SOUTH...SOME SHOWERS ARE APPROACHING THE NORTHWEST COUNTIES. THIS ACTIVITY SHOULD REMAIN IN THE FORM OF SHOWERS AS A STRONG CAPPING INVERSION IS PRESENT ACROSS NORTH TEXAS AT THE PRESENT TIME. FOCUS QUICKLY TURNS TO AN APPROACHING MID LEVEL DISTURBANCE CURRENTLY ENTERING NEW MEXICO. THIS FEATURE INITIALLY WAS NOT SAMPLED WELL BY THE GUIDANCE AS IT WAS OFF THE COAST OF BAJA CALIFORNIA. IT SHOWED UP BETTER IN THE 12Z UPPER AIR ANALYSIS AS A MID LEVEL COLD POCKET OVER TUCSON ARIZONA THIS MORNING AND NOW APPEARS TO BE APPROACHING FAR WEST TEXAS. 12Z GUIDANCE APPEARS TO GENERATE SIGNIFICANTLY MORE FORCING FOR ASCENT WITH THIS FEATURE THIS AFTERNOON DURING PEAK HEATING. BY 00Z A DRYLINE SHOULD BE LOCATED ACROSS THE PANHANDLE AS THE STRONGEST FORCING OVERSPREADS IT. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE AFTERNOON/EARLY EVENING IN AN AREA OF MODERATE INSTABILITY WITH VERY STEEP MID LEVEL LAPSE RATES. THIS SCENARIO WOULD SUPPORT A LARGE HAIL AND DAMAGING WIND THREAT MAINLY ACROSS NORTHWEST TEXAS. IT NOW APPEARS THAT AS THIS FORCING SPREADS EAST...CAPPING ACROSS NORTH TEXAS WILL RAPIDLY WEAKEN AND A CLUSTER OF THUNDERSTORMS WILL SPREAD EAST. THE COVERAGE AND INTENSITY DOES REMAIN SOMEWHAT IN QUESTION FARTHER EAST THOUGH DESPITE AN ERODING CAP. STORMS MAY TEND TO BECOME ELEVATED AS THE BOUNDARY LAYER COOLS AFTER SUNSET. WILL BE ASSESSING SOME HIGH RES GUIDANCE THROUGH EARLY AFTERNOON AND WILL LIKELY UP POPS DURING THE OVERNIGHT TIMEFRAME ACROSS NORTH TEXAS. DUNN && .AVIATION... MVFR CEILINGS ARE EXPECTED THROUGH 18-19Z BEFORE CLOUDS LIFT ABOVE 3000 FEET. SOUTH WINDS 10-16 KNOTS WILL PREVAIL. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP TO THE NORTHWEST OF NORTH TEXAS LATE AFTERNOON/EARLY EVENING AND THEN MOVE SOUTHEAST TONIGHT. THE CHANCES ARE NOT HIGH ENOUGH TO MENTION TSRA IN THE TAFS AT THIS TIME...BUT HAVE PLACED VCSH IN THE METROPLEX TAFS SITES FOR THE 03Z THROUGH 08Z PERIOD. MVFR CEILINGS ARE EXPECTED TO SPREAD BACK NORTH AFTER 07Z AT WACO...AND AFTER 08Z IN THE METROPLEX. 58 && .PREV DISCUSSION... /ISSUED 350 AM CDT FRI MAR 29 2013/ LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING. THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE 00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330 MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY. WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING. PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY. AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR MARGINALLY SEVERE STORM SUNDAY AFTERNOON. ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST. AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH. NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL LOCATIONS...BUT CHANCES ARE THERE EACH DAY. TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN BE EXPECTED. HAMPSHIRE && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40 WACO, TX 77 61 79 64 79 / 5 20 20 20 40 PARIS, TX 73 58 75 60 74 / 20 50 30 50 40 DENTON, TX 75 61 80 58 75 / 10 30 20 40 40 MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40 DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40 TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40 CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40 TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30 MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
630 AM CDT FRI MAR 29 2013 .AVIATION... MVFR CEILINGS ARE EXPECTED THROUGH 18-19Z BEFORE CLOUDS LIFT ABOVE 3000 FEET. SOUTH WINDS 10-16 KNOTS WILL PREVAIL. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP TO THE NORTHWEST OF NORTH TEXAS LATE AFTERNOON/EARLY EVENING AND THEN MOVE SOUTHEAST TONIGHT. THE CHANCES ARE NOT HIGH ENOUGH TO MENTION TSRA IN THE TAFS AT THIS TIME...BUT HAVE PLACED VCSH IN THE METROPLEX TAFS SITES FOR THE 03Z THROUGH 08Z PERIOD. MVFR CEILINGS ARE EXPECTED TO SPREAD BACK NORTH AFTER 07Z AT WACO...AND AFTER 08Z IN THE METROPLEX. 58 && .PREV DISCUSSION... /ISSUED 350 AM CDT FRI MAR 29 2013/ LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING. THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE 00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330 MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY. WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING. PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY. AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR MARGINALLY SEVERE STORM SUNDAY AFTERNOON. ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST. AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH. NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL LOCATIONS...BUT CHANCES ARE THERE EACH DAY. TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN BE EXPECTED. HAMPSHIRE && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40 WACO, TX 77 61 79 64 79 / 5 20 20 20 40 PARIS, TX 73 58 75 60 74 / 20 50 30 50 40 DENTON, TX 75 61 80 58 75 / 10 30 20 40 40 MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40 DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40 TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40 CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40 TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30 MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 58/85
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
350 AM CDT FRI MAR 29 2013 .DISCUSSION... LATEST UPPER AIR ANALYSIS SHOWS TROUGHS OF LOW PRESSURE ACROSS THE NORTHEASTERN CONUS AND NORTHWESTERN CANADA. A SHORTWAVE CAN BE SEEN MOVING ONSHORE BAJA CALIFORNIA AND THIS DISTURBANCE WILL BE THE MAIN FOCUS FOR THE NEXT 24 HOURS. ON THE SURFACE...A LOW CENTER REMAINS POSITIONED NEAR THE TEXAS PANHANDLE WITH A TROUGH EXTENDING TO THE EAST INTO OKLAHOMA. THE 00Z FWD RAOB INDICATED A STOUT CAP IN PLACE AS WEST WINDS BETWEEN 700 AND 800 MB ARE LEADING TO WARM AIR ADVECTION. THIS CAP WILL KEEP NORTH TEXAS RAIN FREE FOR MOST OF THE DAY TODAY. THE FORECAST THEN BECOMES PROBLEMATIC AS THE SHORTWAVE NEARS THE REGION THIS EVENING. THE MODELS DIFFER ON THE HANDLING OF THIS SYSTEM AND THE WEAKENING OF THE CAP BY LATE AFTERNOON. THE GFS KEEPS THE CAP IN PLACE AND MOST OF THE AREA RAIN FREE...WHILE THE NAM/WRF/CANADIAN/ECMWF ALL WEAKEN THE CAP TO SOME DEGREE. THE NAM IS THE MOST AGGRESSIVE WITH THE REMOVAL OF THE CAP COMPLETELY BY 00Z. CURRENTLY ON WATER VAPOR THE SHORTWAVE LOOKS STRONGER THAN WHAT MOST MODELS HAVE INITIALIZED. THE DISTURBANCE IS STRONG ENOUGH THAT IT CAN BE SEEN ON CONSTANT PV SURFACES AS THE TROPOPAUSE DESCENDS IN THE ATMOSPHERE WITHIN THE CENTER OF THE TROUGH OF LOW PRESSURE. THE 00-HR RAP IS CURRENTLY INITIALIZING THIS TO OCCUR AT 330 MB...WHILE THE GFS AND NAM ARE AT 280 MB AND 295 MB RESPECTIVELY. WITH THE STRONGER TROUGH...WILL HOLD MORE WEIGHT WITH THE NAMS FORECAST OF ERODING THE CAP THIS AFTERNOON. HIGH-RES MODELS ARE INITIALIZING THUNDERSTORM DEVELOPMENT WEST/NORTHWEST OF THE FORECAST AREA...NEAR THE SURFACE LOW BEFORE 00Z THIS EVENING. PREVIOUS THINKING WAS THE CAP WOULD HOLD AND THESE STORMS WOULD WEAKEN AS THEY PROGRESSED EAST...RUNNING INTO THE CAP. IF THE CAP DOES ERODE...THERE SHOULD BE A DECENT COVERAGE OF STORMS INTO THE NORTHWEST ZONES AFTER 00Z. WITH CAPE VALUES NEAR 1500 J/KG AND MODERATE SHEAR VALUES A STRONG TO MARGINALLY SEVERE STORM IS POSSIBLE. OVERNIGHT...A COMPLEX OF STORMS IS EXPECTED TO DEVELOP NEAR THE SURFACE TROUGH IN OKLAHOMA AND THIS ACTIVITY COULD CLIP OUR NORTHEASTERN ZONES NEAR SUNRISE SATURDAY. AFTER THIS SYSTEM MOVES OUT ON SATURDAY...THINK THE REMAINDER OF THE DAY SHOULD BE RELATIVELY QUIET AS NO LARGE SCALE FORCING FOR ASCENT IS IN PLACE. SATURDAY NIGHT...THE TROUGH THAT IS CURRENTLY IN NORTHWESTERN CANADA WILL CONTINUE TO SLIDE SOUTHEAST AND SEND A COLD FRONT INTO SOUTHERN OKLAHOMA. THIS FRONT COMBINING WITH ANOTHER WEAK EMBEDDED SHORTWAVE WILL BRING MORE THUNDERSTORM CHANCES TO MAINLY THE NORTHERN ZONES. THIS FRONTAL BOUNDARY IS EXPECTED TO STALL NEAR THE I-20 CORRIDOR SUNDAY AFTERNOON AS THE UPPER LOW SHIFTS EAST. WITH THE SURFACE FOCUS IN PLACE FOR THE CWA...ADDITIONAL THUNDERSTORMS ARE POSSIBLE FOR THE AREA. CAPE VALUES MAY EXCEED 2000 J/KG AS LOWER 60 DEWPOINTS WILL BE IN PLACE. SHEAR IS EXPECTED TO BE WEAKER AND THIS WILL LIMIT THE OVERALL SEVERE POTENTIAL...BUT CANT RULE OUT A STRONG OR MARGINALLY SEVERE STORM SUNDAY AFTERNOON. ANOTHER SOUTHWARD MOVING IMPULSE OF UPPER ENERGY OUT OF CANADA WILL SEND A STRONGER FRONT SOUTH ON MONDAY. THIS FRONT IS EXPECTED TO MOVE THROUGH THE CWA MONDAY EVENING AND WILL CARRY ADDITIONAL THUNDERSTORM CHANCES WITH THE FROPA. MEDIUM RANGE GUIDANCE HAS HAD POOR RUN-TO-RUN CONSISTENCY WITH THE HANDLING OF FEATURES BEYOND MONDAY. THE 00Z GFS AND ECMWF ARE SIMILAR AND KEEP STRONG UPGLIDE ON TOP OF THE FRONTAL INVERSION THROUGH TUESDAY NIGHT AND WILL KEEP SLIGHT TO CHANCE POPS FOR LIGHT RAIN IN THE FORECAST. AFTER A VERY ACTIVE PERIOD...THE FINAL CHANCE OF RAIN WILL COME WHEN THE UPPER TROUGH CURRENTLY OVER THE PACIFIC OCEAN WILL SWING THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. MODELS LAST NIGHT SHOWED THIS LOW WEAKENING BEFORE IT MOVED THROUGH...BUT TONIGHT KEEP IT AS A STRONGER CLOSED LOW. THE TRACK OF THE LOW IS DIFFERENT BETWEEN THE GFS AND ECMWF...BUT BOTH SHOW LARGE SCALE FORCING FOR ASCENT AND WILL FORECAST 30 POPS FOR WEDNESDAY AND WEDNESDAY NIGHT. AGAIN...MODELS HAVE HAD A HARD TIME WITH THE FORECAST BEYOND MONDAY AND CONFIDENCE IS NOT HIGH. NEVERTHELESS...AN UNSETTLED WEATHER PATTERN IS EXPECTED BETWEEN TODAY AND NEXT WEDNESDAY WITH RAIN CHANCES IN THE FORECAST EACH DAY FOR MOST OF THE AREA. IT WONT RAIN EVERYDAY FOR ALL LOCATIONS...BUT CHANCES ARE THERE EACH DAY. TEMPERATURES THROUGH MONDAY WILL BE IN THE 70S/80S FOR HIGHS WITH LOWS IN THE 50S/60S. AFTER MONDAY...TEMPERATURES WILL BE DRASTICALLY COLDER BEHIND THE FRONT. HIGHS BEHIND THE FRONT TUESDAY AND WEDNESDAY WILL BE IN THE 40S/50S FOR HIGHS WITH LITTLE DIURNAL RANGE GIVEN THE CLOUD COVER AND RAIN CHANCES. SOUTH WINDS WILL RETURN BY THE END OF THE WEEK AND MODERATING TEMPERATURES CAN BE EXPECTED. HAMPSHIRE && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 77 62 80 62 76 / 10 30 20 40 40 WACO, TX 77 61 79 64 79 / 5 20 20 20 40 PARIS, TX 73 58 75 60 74 / 20 50 30 50 40 DENTON, TX 75 61 80 58 75 / 10 30 20 40 40 MCKINNEY, TX 75 61 80 60 76 / 10 30 20 40 40 DALLAS, TX 77 62 81 63 76 / 10 30 20 40 40 TERRELL, TX 76 62 79 63 75 / 10 30 20 30 40 CORSICANA, TX 76 60 77 62 78 / 10 20 20 20 40 TEMPLE, TX 76 61 78 62 81 / 5 10 20 20 30 MINERAL WELLS, TX 77 57 83 59 78 / 10 40 20 30 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
547 PM CDT FRI MAR 29 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND SATURDAY ISSUED AT 236 PM CDT FRI MAR 29 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE STRETCHING FROM THE SOUTHEAST CONUS TO THE WESTERN GREAT LAKES EARLY THIS AFTERNOON. MID-LEVEL CLOUD DECK IS SLOWLY MOVING EAST OVER WESTERN WISCONSIN AND IS APPROACHING CENTRAL WISCONSIN. A FEW SPRINKLES HAVE BEEN REPORTED OVER MINNESOTA OUT OF THIS CLOUD DECK BUT AIRMASS IS COMPARATIVELY DRIER OVER CENTRAL WISCONSIN...SO WILL KEEP ANY MENTION OF SPRINKLES OUT OF THE FORECAST. SHORTWAVE TROUGH... WHICH WILL BRING THE NEXT CHANCE OF PRECIP TOMORROW...IS JUST ENTERING THE WESTERN DAKOTAS. AS THIS WAVE AND ATTENDANT COLD FRONT APPROACHES...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...SURFACE HIGH PRESSURE WILL MOVE FROM THE CENTRAL TO THE EASTERN GREAT LAKES...WHILE A SHEARED SHORTWAVE WILL PUSH A COOL FRONT ACROSS THE NORTHERN PLAINS INTO THE NORTHERN MISSISSIPPI VALLEY. SCT TO BKN LOW TO MID-DECK UPSTREAM WILL GRADUALLY MOVE NORTHEAST THROUGH THE NIGHT...BUT DEEPER MOISTURE WILL NOT ARRIVE INTO NORTHWEST WISCONSIN UNTIL LATE TONIGHT. SOUTH TO SOUTHWEST LOW LEVEL WINDS WILL ADVECT IN DRY AIR FROM THE RECEDING AIRMASS...WHICH WILL CAUSE LEVELS BELOW 5-6KFT TO STRUGGLE TO SATURATE. FIRST THOUGHT WAS TO DELAY PRECIP CHANCES BECAUSE OF THIS DRY AIR...BUT AREAS ACROSS THE NORTH MAY STILL REACH ENOUGH SATURATION FOR LIGHT RAIN TO ARRIVE AFTER 09Z. SO WILL TREND A LITTLE SLOWER WITH THE PRECIP CHANCES OVER CENTRAL AND NORTHEAST WISCONSIN...WHICH WILL KEEP THE SE HALF OF THE AREA DRY BEFORE 15Z. THE DRY AIR SHOULD ALLOW TEMPS TO FALL QUICKLY THIS EVENING AND WILL HAVE LOWS AROUND MIDNIGHT...THEN TEMPS SHOULD RISE AS THICKENING CLOUDS ARRIVE. WET BULB TEMPS LOOK TO BE SLIGHTLY ABOVE FREEZING OVER N-C WISCONSIN BY THE TIME THE PRECIP ARRIVES...SO WILL KEEP A MENTION OF FREEZING RAIN OUT OF THE FORECAST. THOUGH WILL MENTION TO THE EVENING CREW TO WATCH TEMPS CLOSELY. LOWS IN THE UPPER 20S TO LOW 30S. SATURDAY...WEAK SHORTWAVE WILL MOVE FROM NORTHERN MINNESOTA TO EASTERN LAKE SUPERIOR AND WILL PUSH THE COOL FRONT ACROSS MOST OF THE STATE EXCEPT FOR EASTERN WISCONSIN. WARM ADVECTION PRECIP OVER NORTH-CENTRAL WISCONSIN WILL LIFT NORTH INTO THE UPPER PENINSULA DURING THE EARLY MORNING. THEN THE 850MB THETAE AXIS WILL SHIFT INTO CENTRAL WISCONSIN BY 15Z AND INTO EASTERN WISCONSIN AFTER 18Z. PRECIP AMOUNTS SHOULD RANGE FROM A QUARTER TO A HALF INCH. HIGHS MAINLY IN THE LOW TO MID 40S. .LONG TERM...SATURDAY NIGHT THROUGH FRIDAY ISSUED AT 236 PM CDT FRI MAR 29 2013 MODELS SHOWED A COLD FRONT...THAT WAS MOVING ACROSS WISCONSIN...EXTENDING FROM NORTHEAST TO SOUTHWEST WISCONSIN AT 00Z SUNDAY. HAVE KEPT LIKELY POPS FOR THE SOUTHEAST PART OF THE AREA DURING THE EARLY PART OF THE EVENING...BUT THEN DOWN TO CHANCE POPS BY LATE EVENING. HAVE A SLIGHT CHANCE FOR SNOW SHOWERS ACROSS THE FAR NORTH LATE IN THE NIGHT AS COLD AIR PASSES OVER THE WARMER LAKE SUPERIOR WATERS IN CYCLONIC FLOW. SNOW AND/OR RAIN SHOWERS REMAIN POSSIBLE ON SUNDAY AS A SECONDARY COLD FRONT PUSHES THROUGH WISCONSIN. THERE WILL BE A CHANCE OF SNOW SHOWERS SUNDAY NIGHT AND MONDAY BUT THEY SHOULD MAINLY BE CONFINED TO VILAS COUNTY AS WINDS BECOME LESS FAVORABLE FOR LAKE EFFECT IN MOST LOCATIONS. CLOUDS AND THE COLD FRONT SHOULD KEEP TEMPERATURES MAINLY IN THE 30S IN THE FAR NORTH ON SUNDAY...AND THE ENTIRE AREA MONDAY AND TUESDAY. A SURFACE HIGH AND UPPER LEVEL RIDGE WILL BRING DRIER CONDITIONS TO THE AREA FOR THE MIDDLE PART OF THE WEEK AND TEMPERATURES SHOULD WARM UP A BIT WITH LESS CLOUD COVER. RETURN FLOW AROUND THE HIGH SHOULD BRING NEAR NORMAL TEMPERATURES TO THE AREA ON THURSDAY. ANOTHER SYSTEM APPROACHING THE AREA WILL BRING A SLIGHT CHANCE OF PRECIPITATION FOR FRIDAY. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 545 PM CDT FRI MAR 29 2013 WL CARRY LOW-END LLWS IN ALL THE TAFS LATE TNGT AS SSWLY FLOW ALOFT INCREASES. EXPECT BAND OF SHRA TO WORK ACRS THE AREA SAT. CIGS MAY HOLD UP INITIALLY AS LOW-LEVELS WL START OUT DRY. A BETTER CHC AT LOWER CIGS DEVELOPING IN THE WAKE OF THE MAIN RAIN BAND AS WINDS DECR NEAR FRONTAL BOUNDARY. && .HYDROLOGY... ISSUED AT 236 PM CDT FRI MAR 29 2013 EXPECT MILD TEMPERATURES FOR THE NEXT TWO DAYS...WITH HIGHS IN MID TO UPPER 40S OVER THE FORECAST AREA. THIS WILL CONTINUE THE GRADUAL MELTING OF THE SNOWPACK. RAIN IS EXPECTED SATURDAY INTO SATURDAY EVENING...WITH PCPN AMOUNTS OF A QUARTER TO HALF INCH POSSIBLE. GIVEN THIS SCENARIO...THE EXPECTED RUNOFF SHOULD CAUSE A GRADUAL RISE IN THE RIVERS OVER THE FORECAST AREA THIS WEEKEND. A FEW RIVERS IN EAST CENTRAL WISCONSIN COULD EXCEED BANKFULL. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......MG AVIATION.......SKOWRONSKI HYDROLOGY......MPC
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SATURDAY ISSUED AT 236 PM CDT FRI MAR 29 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE STRETCHING FROM THE SOUTHEAST CONUS TO THE WESTERN GREAT LAKES EARLY THIS AFTERNOON. MID-LEVEL CLOUD DECK IS SLOWLY MOVING EAST OVER WESTERN WISCONSIN AND IS APPROACHING CENTRAL WISCONSIN. A FEW SPRINKLES HAVE BEEN REPORTED OVER MINNESOTA OUT OF THIS CLOUD DECK BUT AIRMASS IS COMPARATIVELY DRIER OVER CENTRAL WISCONSIN...SO WILL KEEP ANY MENTION OF SPRINKLES OUT OF THE FORECAST. SHORTWAVE TROUGH... WHICH WILL BRING THE NEXT CHANCE OF PRECIP TOMORROW...IS JUST ENTERING THE WESTERN DAKOTAS. AS THIS WAVE AND ATTENDANT COLD FRONT APPROACHES...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...SURFACE HIGH PRESSURE WILL MOVE FROM THE CENTRAL TO THE EASTERN GREAT LAKES...WHILE A SHEARED SHORTWAVE WILL PUSH A COOL FRONT ACROSS THE NORTHERN PLAINS INTO THE NORTHERN MISSISSIPPI VALLEY. SCT TO BKN LOW TO MID-DECK UPSTREAM WILL GRADUALLY MOVE NORTHEAST THROUGH THE NIGHT...BUT DEEPER MOISTURE WILL NOT ARRIVE INTO NORTHWEST WISCONSIN UNTIL LATE TONIGHT. SOUTH TO SOUTHWEST LOW LEVEL WINDS WILL ADVECT IN DRY AIR FROM THE RECEDING AIRMASS...WHICH WILL CAUSE LEVELS BELOW 5-6KFT TO STRUGGLE TO SATURATE. FIRST THOUGHT WAS TO DELAY PRECIP CHANCES BECAUSE OF THIS DRY AIR...BUT AREAS ACROSS THE NORTH MAY STILL REACH ENOUGH SATURATION FOR LIGHT RAIN TO ARRIVE AFTER 09Z. SO WILL TREND A LITTLE SLOWER WITH THE PRECIP CHANCES OVER CENTRAL AND NORTHEAST WISCONSIN...WHICH WILL KEEP THE SE HALF OF THE AREA DRY BEFORE 15Z. THE DRY AIR SHOULD ALLOW TEMPS TO FALL QUICKLY THIS EVENING AND WILL HAVE LOWS AROUND MIDNIGHT...THEN TEMPS SHOULD RISE AS THICKENING CLOUDS ARRIVE. WET BULB TEMPS LOOK TO BE SLIGHTLY ABOVE FREEZING OVER N-C WISCONSIN BY THE TIME THE PRECIP ARRIVES...SO WILL KEEP A MENTION OF FREEZING RAIN OUT OF THE FORECAST. THOUGH WILL MENTION TO THE EVENING CREW TO WATCH TEMPS CLOSELY. LOWS IN THE UPPER 20S TO LOW 30S. SATURDAY...WEAK SHORTWAVE WILL MOVE FROM NORTHERN MINNESOTA TO EASTERN LAKE SUPERIOR AND WILL PUSH THE COOL FRONT ACROSS MOST OF THE STATE EXCEPT FOR EASTERN WISCONSIN. WARM ADVECTION PRECIP OVER NORTH-CENTRAL WISCONSIN WILL LIFT NORTH INTO THE UPPER PENINSULA DURING THE EARLY MORNING. THEN THE 850MB THETAE AXIS WILL SHIFT INTO CENTRAL WISCONSIN BY 15Z AND INTO EASTERN WISCONSIN AFTER 18Z. PRECIP AMOUNTS SHOULD RANGE FROM A QUARTER TO A HALF INCH. HIGHS MAINLY IN THE LOW TO MID 40S. .LONG TERM...SATURDAY NIGHT THROUGH FRIDAY ISSUED AT 236 PM CDT FRI MAR 29 2013 MODELS SHOWED A COLD FRONT...THAT WAS MOVING ACROSS WISCONSIN...EXTENDING FROM NORTHEAST TO SOUTHWEST WISCONSIN AT 00Z SUNDAY. HAVE KEPT LIKELY POPS FOR THE SOUTHEAST PART OF THE AREA DURING THE EARLY PART OF THE EVENING...BUT THEN DOWN TO CHANCE POPS BY LATE EVENING. HAVE A SLIGHT CHANCE FOR SNOW SHOWERS ACROSS THE FAR NORTH LATE IN THE NIGHT AS COLD AIR PASSES OVER THE WARMER LAKE SUPERIOR WATERS IN CYCLONIC FLOW. SNOW AND/OR RAIN SHOWERS REMAIN POSSIBLE ON SUNDAY AS A SECONDARY COLD FRONT PUSHES THROUGH WISCONSIN. THERE WILL BE A CHANCE OF SNOW SHOWERS SUNDAY NIGHT AND MONDAY BUT THEY SHOULD MAINLY BE CONFINED TO VILAS COUNTY AS WINDS BECOME LESS FAVORABLE FOR LAKE EFFECT IN MOST LOCATIONS. CLOUDS AND THE COLD FRONT SHOULD KEEP TEMPERATURES MAINLY IN THE 30S IN THE FAR NORTH ON SUNDAY...AND THE ENTIRE AREA MONDAY AND TUESDAY. A SURFACE HIGH AND UPPER LEVEL RIDGE WILL BRING DRIER CONDITIONS TO THE AREA FOR THE MIDDLE PART OF THE WEEK AND TEMPERATURES SHOULD WARM UP A BIT WITH LESS CLOUD COVER. RETURN FLOW AROUND THE HIGH SHOULD BRING NEAR NORMAL TEMPERATURES TO THE AREA ON THURSDAY. ANOTHER SYSTEM APPROACHING THE AREA WILL BRING A SLIGHT CHANCE OF PRECIPITATION FOR FRIDAY. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 236 PM CDT FRI MAR 29 2013 HIGH PRESSURE WILL DRIFT SE TODAY...REACHING SOUTHERN LAKE MICHIGAN THIS EVENING. THE HIGH WILL BRING VFR CONDITIONS TO THE FORECAST AREA...WITH INCREASING MID-LEVEL CLOUDS DURING THE EVENING. SOUTH TO SOUTHWEST WINDS WILL BRING AN INCREASE IN MOISTURE LATE TONIGHT... AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE NORTHWEST. THIS SYSTEM WILL BRING SCT RAIN SHOWERS TO MAINLY NC WI AFTER 09Z/SAT. && .HYDROLOGY... ISSUED AT 236 PM CDT FRI MAR 29 2013 EXPECT MILD TEMPERATURES FOR THE NEXT TWO DAYS...WITH HIGHS IN MID TO UPPER 40S OVER THE FORECAST AREA. THIS WILL CONTINUE THE GRADUAL MELTING OF THE SNOWPACK. RAIN IS EXPECTED SATURDAY INTO SATURDAY EVENING...WITH PCPN AMOUNTS OF A QUARTER TO HALF INCH POSSIBLE. GIVEN THIS SCENARIO...THE EXPECTED RUNOFF SHOULD CAUSE A GRADUAL RISE IN THE RIVERS OVER THE FORECAST AREA THIS WEEKEND. A FEW RIVERS IN EAST CENTRAL WISCONSIN COULD EXCEED BANKFULL. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......MG AVIATION.......MPC HYDROLOGY......MPC
AREA FORECAST DISCUSSION...CORRECTED
NWS LA CROSSE WI
1137 PM CDT THU MAR 28 2013 .SHORT TERM...TONIGHT THROUGH SUNDAY 345 PM CDT THU MAR 28 2013 AT 3 PM...A 1028 MB SURFACE HIGH WAS CENTERED OVER SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN. DESPITE THIS HIGH PRESSURE AREA...A BROKEN DECK OF MID CLOUDS WERE LOCATED ACROSS THIS AFOREMENTIONED AREA. THIS WAS DUE TO MODERATE WARM AIR ADVECTION AHEAD OF A SHORT WAVE MOVING THROUGH SOUTHWEST MINNESOTA. OVERALL THE 28.17Z RAP MODEL IS HANDLING THESE CLOUDS THE BEST. THEY SHOW THAT THESE MID CLOUDS WILL MOVE SOUTHEAST OUT OF THE AREA BY 29.03Z...AND THEN SOME MORE MID CLOUDS WILL MOVE BACK INTO THE AREA FROM WESTERN MINNESOTA AND DAKOTAS AFTER 29.06Z. THESE CLOUDS ARE THE RESULT OF SOME WARM AIR ADVECTION AHEAD OF YET ANOTHER SHORT WAVE TROUGH MOVING OUT OF NORTH DAKOTA. SOUNDINGS SUGGEST THAT THIS MOISTURE WILL LIMITED TO A 100 TO 150 MB LAYER AROUND 700 MB. AS A RESULT...NOT EXPECTING ANY PRECIPITATION FROM THIS WAVE. THIS IS IN DESPITE THE GFS TRYING TO GENERATE SOME PRECIPITATION JUST UPSTREAM OF THE FORECAST AREA. FROM LATE FRIDAY NIGHT INTO SATURDAY EVENING...A STRONG SHORT WAVE TROUGH WILL MOVE SOUTHEAST THROUGH THE FORECAST AREA. AHEAD OF THIS WAVE...THERE WILL BE MODERATE TO STRONG 290K ISENTROPIC LIFT...AND MODERATE 925 MB TO 850 MB MOISTURE TRANSPORT. THIS WILL RESULT IN THE DEVELOPMENT OF A BAND OF RAIN ALONG AND AHEAD OF THIS FRONT. INSTABILITY STILL LOOKS LIMITED WITH MOST UNSTABLE CAPES CLIMBING UP TO 100 J/KG. AS A RESULT...LEFT ISOLATED THUNDERSTORMS IN THE FORECAST MAINLY ALONG AND SOUTH OF INTERSTATE 90. TEMPERATURES AT THE ONSET OF THIS PRECIPITATION MAY RESULT IN A BRIEF WINTRY MIX OF FREEZING RAIN AND SLEET MAINLY NORTHEAST OF INTERSTATE 94. THERE MAY BE A BRIEF PERIOD OF GLAZING. HOWEVER... IT WILL SHORT-LIVED AS TEMPERATURES CLIM QUICKLY INTO THE 40S. ON SUNDAY...A STRONG CANADIAN COLD FRONT WILL MOVE SOUTHEAST THROUGH THE FORECAST AREA. THERE IS VERY LITTLE 925 AND 850 MB MOISTURE TRANSPORT ASSOCIATED WITH THIS FRONT. IN THE WAKE OF THIS FRONT...THERE WILL BE MODERATE 290K ISENTROPIC LIFT. HOWEVER SUBSIDENCE IN THE WAKE OF THIS FRONT WILL CAUSE CONDENSATION PRESSURE DEFICITS TO RISE INTO THE 50 TO 100 MB RANGE. AS A RESULT...THERE IS A QUESTION ON WHETHER THERE WILL BE ENOUGH MOISTURE FOR ANY RAIN AND SNOW SHOWERS DURING THE AFTERNOON AND EVENING...THUS...KEPT PRECIPITATION CHANCES ON THE LOW SIDE MAINLY NORTH OF INTERSTATE 94. .LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY 345 PM CDT THU MAR 28 2013 FROM SUNDAY NIGHT INTO TUESDAY...IT CONTINUES TO LOOK LIKE ANOMALOUS COLD AIR MASS WILL BE LOCATED ACROSS THE AREA. THE ECMWF 850 TEMPERATURES ARE RUNNING 1 TO 1.5 STANDARD DEVIATIONS BELOW NORMAL ON MONDAY...AND AROUND 1 STANDARD DEVIATION BELOW NORMAL ON TUESDAY. THIS WILL RESULT IN HIGH TEMPERATURES IN THE LOWER AND MID 30S ON MONDAY...AND IN THE MID AND UPPER 30S ON TUESDAY. ON WEDNESDAY...ANOTHER COLD FRONT WILL MOVE SOUTHEAST THROUGH THE REGION. AT THIS TIME...IT LOOKS LIKE THE BEST MOISTURE AND LIFT WILL BE TO OUR NORTH...THUS KEPT THE FORECAST DRY. LOOKING AHEAD TO THE FIRST HALF OF APRIL...THE CFS VERSION 2 CONTINUES TO SHOW THAT THE AREA WILL SEE PREDOMINANTLY NORTHWEST FLOW. AS A RESULT...IT CONTINUES TO SHOW COLDER-THAN-NORMAL TEMPERATURES PERSISTING THROUGH THIS TIME PERIOD. THE MAIN REASON FOR THIS IS THAT THE ARCTIC OSCILLATION REMAINS NEGATIVE. && .AVIATION...FRIDAY 1137 PM CDT THU MAR 28 2013 QUIET VFR CONDITIONS WILL PREVAIL FOR MOST OF FRIDAY AS HIGH PRESSURE SLOWLY RETREATS EASTWARD. JUST PATCHY MID LEVEL CLOUDS MOVING THROUGH WESTERN GREAT LAKES AS LOW LEVEL FLOW BECOMES SOUTHEASTERLY THROUGH THE MORNING. DEW POINTS A BIT HIGHER CLOSER TO INTERSTATE 35 AND WITH TEMPERATURES STAYING UP COULD SEE SOME LIGHT FOG /4-6SM BR/ DEVELOP OVER PARTS OF NORTHEAST IOWA AND SOUTHEAST MINNESOTA. ALREADY SEEING SOME MINOR RESTRICTIONS TO VISIBILITIES CLOSER TO SOUTH DAKOTA BORDER. SOME INCREASE IN CLOUDS NOTED AHEAD OF CANADIAN SHORT WAVE TROUGH BY FRIDAY EVENING BUT PRECIPITATION THREAT SHOULD HOLD OFF UNTIL AFTER 30/06Z. && .HYDROLOGY... 345 PM CDT THU MAR 28 2013 DUE TO A MELTING SNOWPACK OVER THE LAST SEVERAL DAYS...MANY RIVERS ACROSS NORTHEAST IA/SOUTHEAST MN/AND SOUTHWEST WI HAVE EXPERIENCED WITHIN BANK RISES OF 2 TO 4 FEET. IN AREAS WHERE THE SNOW HAS MELTED...SOME OF THE FROST HAS MELTED IN THE TOP FEW INCHES OF THE SOIL...THIS IS ALLOWING SOME OF THE SNOW MELT TO GET INTO THE TOP SOILS. THIS MOISTURE THEN FREEZES IN THE TOP SOILS AT NIGHT. THIS IS LIMITING THE AMOUNT OF RUNOFF INTO THE RIVERS. ON SATURDAY...LOOK FOR A QUARTER TO HALF INCH OF RAIN. THIS WILL ADD ONTO THE RUNOFF FROM THE SNOW MELT. HOWEVER THE WARM RAINS WILL HELP TO MELT SOME FROST IN THE TOP SOILS...SO NOT LOOKING FOR COMPLETE RUNOFF LIKE WE HAD EARLIER IN THE MONTH. WHILE NO FLOODING IS EXPECTED AT THIS TIME...PEOPLE LIVING NEAR OR HAVING INTERESTS ALONG RIVER WAYS ARE URGED TO MONITOR LATEST RIVER FORECASTS AND STATEMENTS. && .ARX WATCHES/WARNINGS/ADVISORIES... 243 PM CDT THU MAR 28 2013 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION....SHEA HYDROLOGY...DAS/BOYNE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
845 PM MST SAT MAR 30 2013 .SYNOPSIS...CLEARING TONIGHT...OTHERWISE DRY AND WARM INTO NEXT WEEK. A LOW PRESSURE SYSTEM SKIRTING BY NORTHEAST OF THE AREA WILL BRING A FEW DEGREES OF COOLING AND GUSTY WINDS AT TIMES THE FIRST HALF OF THE WEEK. && .DISCUSSION...FLAT RIDGE WITH MODEST WESTERLY FLOW UNDER LOW STILL OFF THE CALIFORNIA COAST. CONSIDERABLE CLOUDINESS ABOVE H7 EARLIER BUT NICE SECONDARY DRY SLOT ON WATER VAPOR IMAGERY PUSHING INTO SOUTHWEST AND SOUTHERN ARIZONA THIS EVENING. WE UPDATED EARLIER TO ACCELERATE THE OVERALL CLEARING TREND...WHILE TWEAKING SOME OVERNIGHT LOWS DOWN A FEW DEGREES WITH MORE COMPLETE CLEARING BEFORE SUNRISE. OTHERWISE NO SURPRISES WITH CURRENT ANALYSIS AND EARLY LOOKS AT 00Z NAM AND DERIVATIVE SUITE TRENDS OR RECENT HRRR OUTPUT. && .PREV DISCUSSION...WARM CLOUDY DAY ACROSS THE AREA WITH SOME AREAS OF VIRGA. THE BACK EDGE OF CLOUDS HAS PUSHED THROUGH SW ARIZONA THIS AFTERNOON AND EXPECT THIS TO PUSH EAST TONIGHT INTO EASTER SUNDAY MORNING. THUS EXPECT A CLOUDY START TO TH EVENING THEN BECOMING MOSTLY CLEAR TOWARD MORNING. OVERNIGHT LOWS...DUE TO LESS CLOUD COVER...WILL BE COOLER THAN THIS MORNING. UPPER LOW CURRENTLY SPINNING OFF CENTRAL CALIFORNIA COAST WILL AMPLIFY RIDGE OVER THE AREA SUNDAY AS IT MOVES CLOSER TO THE BAY AREA. UPPER LOW TO MOVE INLAND SUNDAY EVENING...THEN ACROSS NEVADA MONDAY MORNING...ACROSS SOUTHERN UTAH MONDAY AFTERNOON/EVENING... THE FOUR CORNERS TUESDAY MORNING...AND OVER WESTERN NEW MEXICO TUESDAY AFTERNOON. MOISTURE RATHER LIMITED AND NEAR THE CENTER OF THE LOW. HAVE UPPED POPS A BIT IN THE WHITES ON TUESDAY BUT STILL ON THE SLIGHT CHANCE SIDE. COOLER TUESDAY WITH HIGHS NEAR NORMAL. SOME BREEZES MONDAY AND TUESDAY. WARMER THE REMAINDER OF THE WEEK AS UPPER RIDGE AMPLIFIES OVER THE DESERT SW. && .AVIATION...CLEARING FROM THE WEST...SCT-BKN ABV 12K FT AGL EARLY...BECOMING SKC OVERNIGHT THROUGH SUNDAY. NORMAL DIURNAL WIND TRENDS GENERALLY LESS THAN 8 KTS OVERNIGHT...BECOMING WESTERLY 10-12 KTS AND GUSTY AT TIMES SUNDAY AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...CLEARING TONIGHT AND SUNDAY AS WEAK HIGH PRESSURE ALOFT BUILDS IN. MEANWHILE...WE`RE WATCHING AN AREA OF LOW PRESSURE ACROSS THE EASTERN PACIFIC THAT WILL TRACK TO THE NORTH OF SOUTHERN ARIZONA EARLY THIS WEEK. THERE WILL BE A SLIGHT CHANCE OF SHOWERS IN THE HIGHER TERRAIN OF THE WHITE MOUNTAINS TUESDAY. WINDS WILL ALSO INCREASE AND BECOME BREEZY MAINLY MONDAY AND TUESDAY AFTERNOON. THEREAFTER...AN AREA OF HIGH PRESSURE WILL BUILD BACK IN STARTING WEDNESDAY THROUGH THE END OF THE WEEK WITH DRY CONDITIONS AND JUST A FEW AFTERNOON BREEZES. TEMPERATURES WILL REMAIN ABOVE NORMAL MOST OF THIS WEEK WITH NEAR NORMAL TEMPERATURES TUESDAY. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON MEYER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
240 AM MDT SUN MAR 31 2013 .SHORT TERM...GENERALLY DRY NW FLOW WILL BE OVER THE AREA THRU THIS AFTN AS SFC LOW PRES DEVELOPS OVER ERN CO. 850-700 MB TEMPS ARE A DEGREE OR TWO WARMER THIS AFTN SO WILL KEEP HIGHS IN THE 65 TO 70 DEGREE RANGE OVER NERN CO. FOR TONIGHT THE FLOW ALOFT WILL BECOME MORE WSW AS A WEAK UPPER LEVEL LOW BEGINS TO MOVE TOWARDS THE GREAT BASIN. SOME MOISTURE WILL INCREASE IN THE MTNS LATE TONIGHT SO WILL MENTION A SLIGHT CHC OF -SHSN WEST OF THE DIVIDE AFTER MIDNIGHT. OVER NERN CO A CDFNT WILL BACKDOOR INTO THE AREA OVERNIGHT HOWEVER OUTSIDE OF SOME INCREASE IN LOW LVL CLOUDS AT THIS TIME DO NOT EXPECT ANY PCPN. .LONG TERM...MODELS SLOWER WITH WEAK UPPER LOW. NOW ITS OVER THE FOUR CORNERS FROM 18Z TO 00Z TUESDAY AFTERNOON. IT WEAKENS AND BECOMES AN OPEN TROUGH...ITS AXIS IS OVER EASTERN COLORADO AT 12Z WEDNESDAY MORNING. THE FLOW ALOFT IS PRETTY WEAK ACROSS THE CWA FROM MONDAY NIGHT THROUGH TUESDAY NIGHT. THERE IS UPWARD SYNOPTIC SCALE ENERGY PROGGED FOR THE CWA MONDAY THROUGH TUESDAY NIGHT. THE BOUNDARY LAYER FLOW IS PROGGED TO BE UPLSOPE MONDAY THROUGH MUCH OF TUESDAY NIGHT...WITH EITHER EAST OR SOUTHEAST DIRECTIONS. THE MOISTURE IS NOT AS EXTENSIVE AND PROLONGED AS PREVIOUS MODEL RUNS INDICATED. THE QPF FIELDS DO NOT START MEASURABLE PRECIPITATION UNTIL LATER MONDAY MORNING. MODELS SHOW MEASURABLE PRECIPITATION INTO WEDNESDAY MORNING NOW. THE AMOUNTS ARE LESS THAN YESTERDAY`S 00Z RUNS INDICATED. SO RATHER THAN CHASING THE LATEST/GREATEST MODELS AND AT THE RISK OF CONTINUING TO YO-YO THE FORECAST...WILL CHANGE VERY LITTLE THROUGH TUESDAY NIGHT. TEMPERATURES LOOK CONSIDERABLY WARMER ON MONDAY THAN YESTERDAY`S 00Z RUNS INDICATED. MONDAY`S HIGHS ARE NOW ONLY 4-7 COOLER THAN SUNDAY`S HIGHS. TUESDAY`S HIGHS ARE 1-3 C COOLER THAN MONDAY`S. AGAIN WILL LEAVE THINGS STATUS QUO THIS UPDATE. FOR THE LATER DAYS...WEDNESDAY THROUGH SATURDAY...THERE IS UPPER RIDGING INTO FRIDAY MORNING ...THEN A WEAK UPPER TROUGH MOVES ACROSS FRIDAY NIGHT...AND MORE RIDGING SATURDAY. && .AVIATION...LIGHT DRAINAGE WINDS THRU THE MORNING HOURS WILL BECOME NWLY BY EARLY AFTN. LATEST RAP SHOWS WINDS COULD GUSTY UP TO 20 MPH FOR A FEW HOURS BETWEEN 22Z AND 00Z BEFORE DECREASING. TONIGTH A CDFNT WILL BACKDOOR INTO THE AREA BETWEEN 03Z AND 06Z WITH WINDS BECOMING MORE NELY. AFTER 06Z WINDS WILL SHIFT TO LIGHT ESE. TOWARDS 12Z MAY SEE SOME STRATUS WITH CEILINGS IN THE 2000-3000 FT RANGE. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM....RJK AVIATION...RPK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
355 AM EDT SUN MAR 31 2013 .SYNOPSIS... 07Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE BEGINNINGS OF A PATTERN AMPLIFICATION THAT WILL OCCUR ACROSS THE EASTERN HALF OF THE CONUS THROUGH THE EARLY PORTION OF THE WEEK. THE OVERALL PATTERN CONTINUES TO SHOW A CONVERGENT FLOW OVER THE WESTERN THIRD OF THE NATION FOLLOWED BY A GENERAL DOWNSTREAM WEST TO EAST REGIME. THIS WESTERLY FLOW IS JUST NOW BEGINNING TO AMPLIFY AS A SERIES OF SHORTWAVES EJECT SOUTHWARD FROM SOUTHERN CANADA. TWO FEATURES WITHIN THE FLOW THAT WILL INFLUENCE OUR WEATHER THROUGH THE SHORT TERM INCLUDE A SHORTWAVE CURRENTLY MOVING EASTWARD ALONG THE NORTHERN GULF COAST...AND ANOTHER SHORTWAVE STILL UP OVER THE HIGH PLAINS THAT WILL RAPIDLY PUSH TOWARD THE SOUTHEASTERN CONUS. AT THE SURFACE...HIGH PRESSURE IS RIDGING BACK ACROSS THE PENINSULA AND EASTERN GULF OF MEXICO FROM A POSITION NEAR THE NORTHERN BAHAMA ISLANDS. THE RIDGE AXIS IS ACROSS THE SOUTHERN HALF OF THE PENINSULA GIVING OUR FORECAST AREA A LIGHT SOUTHEAST TO SOUTH FLOW. AN INCREASE IN COLUMN MOISTURE AND A LESS FAVORABLE RIDGE POSITION WILL HELP KEEP TEMPERATURES EARLY THIS MORNING CONSIDERABLY WARMER FOR MOST SPOTS THAN WHAT HAS BEEN EXPERIENCED THE PAST SEVERAL NIGHTS. && .SHORT TERM (TODAY THROUGH TUESDAY)... TODAY/TONIGHT... A GENERALLY QUIET AND WARM DAY IN STORE FOR THE REGION AS WE RESIDE BETWEEN PASSING SHORTWAVES FOR THE DAYLIGHT HOURS. HIGH PRESSURE AT THE SURFACE WILL DOMINATE THE LOWER LEVELS AS IT RIDGES WESTWARD ACROSS THE SOUTH-CENTRAL PENINSULA. AN AMPLIFYING UPPER LEVEL PATTERN ACROSS THE EASTERN HALF OF THE NATION WILL PROPEL A SURFACE COLD FRONT INTO THE SOUTHEASTERN STATES...HOWEVER IT SEEMS APPARENT THAT THE BEST COMBINATION OF FRONTAL FOCUS AND DEEP LAYER SYNOPTIC FORCING AHEAD OF THE APPROACHING SHORTWAVE WILL STAY NORTH AND NORTHWEST OF THE FORECAST ZONES THROUGH THE EVENING. A LIGHT SOUTH TO SOUTHEAST FLOW IN THE MORNING WILL TURN SOUTHWEST NEAR THE COAST AS STRONG TERRESTRIAL HEATING FORCE SEA-BREEZE CIRCULATIONS. HIGH TEMPERATURES WILL BE NEAR SEASONABLE NORMS FOR THE FINAL DAY OF MARCH UNDER A MIX OF SUN AND CLOUDS. LOOKING FOR HIGHS APPROACHING 80 NORTH OF I-4 AND INTO THE LOWER 80S SOUTH AWAY FROM THE COAST. WOULD EXPECT AFTERNOON TEMPS TO BE AT LEAST SEVERAL DEGREES COOLER AT THE BEACHES DUE TO THE DEVELOPING ONSHORE FLOW OFF THE COOLER SHELF WATERS...ESPECIALLY ALONG THE NATURE COAST. TONIGHT...WILL SEE THE COLD FRONT CONTINUE TO SETTLE SOUTHWARD TO A POSITION JUST NORTH OF I-10 BY SUNRISE. THE CLOSER PROXIMITY OF THIS BOUNDARY AND THE SHORTWAVE WILL BRING A CHANCE FOR A FEW SHOWERS TO THE NORTHERN NATURE COAST...MAINLY LEVY/CITRUS COUNTIES DURING THE SECOND HALF OF THE NIGHT. HOWEVER...APPEARS THE BEST CHANCE OF SHOWER FOR THESE ZONES WILL STILL HOLD OFF UNTIL THE DAYLIGHT HOURS OF MONDAY MORNING WHEN THE BEST SYNOPTIC FORCING ARRIVES. MONDAY/MONDAY NIGHT... SURFACE RIDGE DROPS SOUTHWARD OUT OF THE AREA IN RESPONSE TO THE ARRIVAL OF THE SURFACE FRONT ACROSS NORTHERN FLORIDA. AS MENTIONED ABOVE...EXPECT TO SEE A SCATTERING OF SHOWERS DURING THE MORNING/EARLY AFTERNOON HOURS TO THE NORTH OF TAMPA BAY IN RESPONSE TO A FAVORABLE COMBINATION OF SURFACE FOCUS AND QG-FORCING. FURTHER SOUTH...THE RAINFALL POTENTIAL IS MORE TRICKY. A BETTER MOISTURE PROFILE... CONVERGENT INLAND FLOW AND AT LEAST SOME SYNOPTIC SUPPORT INTO THE AFTERNOON SUGGESTS THAT AT LEAST WIDELY SCT CONVECTION MAY FIRE ALONG THE INLAND PROPAGATING SEA-BREEZE BOUNDARY. A BIT EARLY IN THE YEAR FOR THIS...BUT WITH THE SYNOPTIC SUPPORT...ITS NOT OUT OF THE QUESTION. MOST AVAILABLE CONVECTION ALLOWING MODELS ARE ALSO SHOWING THE SHOWER/ISOLATED STORM POTENTIAL...MAINLY EAST OF THE I-75 CORRIDOR. THIS SCENARIO AND CONVECTIVE PLACEMENT MAKES SENSE GIVEN THE QUICK INLAND MOVEMENT OF THE SEA-BREEZE. IT WOULD ALSO SUGGEST THAT ANY ACTIVITY THAT DOES DEVELOP WILL QUICKLY TRANSLATE TOWARD THE I-95 CORRIDOR BY LATE AFTERNOON/EARLY EVENING. WILL ATTEMPT TO REPRESENT THIS PHILOSOPHY OF THE AREAL COVERAGE AND TIMING IN THE POP GRIDS. MONDAY NIGHT...SURFACE FRONT QUICKLY WASHES OUT AS IT TRIES TO MOVE SOUTH INTO THE FL PENINSULA. THIS LOSS OF FOCUS ALONG WITH THE DEPARTURE OF THE SHORTWAVE ENERGY SHOULD BRING A RATHER QUICK END TO ANY LINGERING SHOWERS...AND BASICALLY HAVE A DRY OVERNIGHT PERIOD IN THE GRIDS. ONE CONCERN THAT WILL NEED TO BE EVALUATE WITH FUTURE FORECAST PACKAGES IS THE POTENTIAL FOR SEA-FOG DEVELOPING MONDAY AFTERNOON/EVENING...AND POSSIBLY EXPANDING ONSHORE WITH TIME. THE LATEST SREF GUIDANCE IS QUITE AGGRESSIVE WITH THIS SCENARIO...AND GIVEN THE HIGHER DEWPOINT AIR THAT WILL BE ARRIVING...AND THE STILL COOL SHELF WATERS AFTER SUCH A COLD MARCH...IT IS CERTAINLY PLAUSIBLE. TUESDAY... A PLEASANT AND WARM SPRING DAY LOOKS LIKELY UNDER A ZONAL FLOW PATTERN. A MIX OF SUN AND CLOUD WILL BE FORECAST WITH TEMPERATURES CLIMBING INTO THE 80 AWAY FROM THE BEACHES WHERE DEVELOPING ONSHORE FLOW SHOULD ONCE AGAIN KEEP TEMPS COOLER. A FEW OF THE GLOBAL MODELS ALONG WITH THE SREF ARE KICKING OFF THEIR CONVECTIVE PARM SCHEMES SOUTH OF I-4 DURING THE AFTERNOON...HOWEVER...GIVEN THE TIME OF YEAR AND LACK OF ANY SYNOPTIC FORCING...MENTIONABLE SHOWER CHANCES SEEM UNLIKELY. WILL KEEP RAIN CHANCES OUT OF THE FORECAST FOR THE ENTIRE AREA. && .LONG TERM (TUESDAY NIGHT THROUGH NEXT SATURDAY)...THE AREA STARTS OFF UNDER NEARLY ZONAL FLOW ALOFT...A RESULT OF A SHORT WAVE TROUGH/LOW OVER THE FOUR CORNERS REGION AND A SECOND LOW OVER THE LOWER SAINT LAWRENCE VALLEY. AT THE SURFACE...HIGH PRESSURE IN THE UPPER MISSISSIPPI VALLEY RIDGES TO THE SE U.S. AS THE REMNANTS OF A FRONTAL BOUNDARY RESIDES ACROSS FL AND THE EAST GULF OF MEXICO. AS THE WEEK PROGRESSES THE FOUR CORNERS TROUGH/LOW TRACKS INTO THE SOUTHERN PLAINS/WESTERN GULF COAST...FORMING A SURFACE TROUGH/LOW OVER THE WESTERN GULF. THIS ALONG WITH THE SURFACE RIDGE THAT SHIFTS OFFSHORE FROM THE SE U.S. WILL INCREASE LOW LEVEL FLOW AND SHIFT IT TO SE AND SOUTHERLY. BY FRI THE UPPER TROUGH IS SOMEWHERE ALONG THE GULF COAST WITH IT/S SURFACE REFLECTION IN THE NE GULF TO CAROLINA COASTAL AREA. ON SAT THE UPPER TROUGH HAS REACHED THE EASTERN SEABOARD WITH THE SURFACE FEATURE OVER ATLANTIC COAST WATERS...TRAILING A COLD FRONT THAT WILL BE EAST OF THE STATE. THE MODELS ARE IN GENERAL AGREEMENT WITH THE BIG PICTURE BUT CONTINUE TO DIFFER IN MINOR DETAILS LIKE LOCATION...TIMING AND STRENGTH. ALTHOUGH THE 31/00Z ECMWF IS NOW MORE IN LINE WITH THE LATEST GFS THAN THE PREVIOUS ECMWF WAS. CLOUDS ALONG WITH RAIN CHANCES WILL GRADUALLY INCREASE THEN DECREASE SHARPLY SAT. FOR NOW HAVE KEPT JUST SHOWERS AND NO MORE THAN 50 POPS. WINDS WILL BECOME ROBUST...BUT MAINLY A MARINE ISSUE. TEMPERATURES WILL RUN ABOVE NORMAL ALTHOUGH THEY WILL DROP SOME FOR SAT. && .AVIATION... VFR CONDITIONS CONTINUE FOR THE NEXT 24 HOURS UNDER FEW-SCT CU OR SC AND SCT-BKN CIRRUS. EAST AND SE WINDS BECOME ONSHORE IN THE AFTERNOON IN THE 10-12 KT RANGE. && .MARINE... HIGH PRESSURE WILL REMAIN IN CONTROL OF THE EASTERN GULF OF MEXICO THROUGH TONIGHT AND THEN RETREAT SOUTH AND EAST IN RESPONSE TO AN APPROACHING COLD FRONT FROM THE NORTH. THIS FRONT WILL WASH OUT AS IT ARRIVES OVER THE NORTHERN GULF AND BE QUICKLY REPLACED BY HIGH PRESSURE RIDGING IN FROM THE NORTH ON TUESDAY. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW HEADLINE CRITERIA THROUGH TUESDAY. AFTERNOON SEA-BREEZES CAN BE EXPECTED TO TURN WINDS ONSHORE NEAR THE COAST EACH DAY. && .FIRE WEATHER... A CONTINUED SLOW INCREASE IN LOW LEVEL MOISTURE SHOULD GENERALLY PREVENT RED FLAG CONDITIONS FROM BEING REACHED TODAY. CONDITIONS WILL BE MARGINAL FOR POLK AND HIGHLANDS COUNTIES WHERE 3 TO 4 HOURS CRITICAL RELATIVE HUMIDITY IS CURRENTLY FORECAST. ENOUGH MOISTURE WILL ARRIVE BY MONDAY TO PREVENT ANY CRITICALLY LOW RELATIVE HUMIDITY ACROSS WEST CENTRAL AND SOUTHWEST FLORIDA. && .PRELIMINARY POINT TEMPS/POPS... TPA 78 63 78 63 / 0 10 20 10 FMY 83 64 84 64 / 10 10 20 10 GIF 84 61 83 60 / 10 10 40 10 SRQ 78 63 78 63 / 0 10 20 10 BKV 81 59 80 57 / 0 10 30 10 SPG 79 65 79 64 / 0 10 20 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM/AVIATION/DSS...RUDE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
603 PM CDT SAT MAR 30 2013 ...UPDATE TO AVIATION... .SYNOPSIS... ISSUED AT 215 PM CDT SAT MAR 30 2013 THE LONGWAVE PATTERN WAS CHARACTERIZED BY NORTHWEST FLOW FROM WESTERN CANADA INTO THE CENTRAL CONUS. SEVERAL SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW PATTERN COULD BE IDENTIFIED ON WATER VAPOR LOOP AND RAP ANALYSIS. THE DISTURBANCE WHICH LED TO LAST NIGHT`S SEVERE WEATHER EVENT WAS LOCATED OVER MISSOURI AND ARKANSAS EARLY THIS AFTERNOON. FARTHER UPSTREAM...ANOTHER SHORTWAVE TROUGH WAS EVIDENT FROM WYOMING TO SOUTH DAKOTA. MEANWHILE...A FAIRLY LARGE UPPER LOW WAS CENTERED OFF THE COAST OF CALIFORNIA DISCONNECTED FROM THE POLAR JET STREAM FLOW. A SUBTROPICAL JET CONTAINED A FAIR AMOUNT OF HIGH LEVEL CIRRUS IN THE LOW LATITUDES SOUTH OF THE AFOREMENTIONED UPPER LOW INTO WESTERN MEXICO. AT THE SURFACE...A WEAK TROUGH AXIS EXTENDED FROM NORTHEAST KANSAS INTO WESTERN OKLAHOMA. THE NORTH TO NORTHWEST WINDS BEHIND THE TROUGH AXIS HAD LOWER MOISTURE CONTENT WITH DEWPOINTS IN THE UPPER 30S TO LOWER 40S. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 403 PM CDT SAT MAR 30 2013 THE SHORTWAVE TROUGH MOVING SOUTHEAST ACROSS WESTERN NEBRASKA WILL AID IN THE DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS LATE THIS AFTERNOON ACROSS SOUTHWEST NEBRASKA AND NORTHEAST COLORADO. THE AIRMASS IN THIS REGION IS DRY WITH DEWPOINT TEMPERATURES ONLY IN THE LOWER TO MID 30S. STEEP LAPSE RATES WERE FOUND AHEAD OF THIS SHORTWAVE TROUGH AS SURFACE TEMPERATURES WARM INTO THE LOWER TO MID 60S...AND MID LEVEL TEMPERATURES WERE COLD (-20 TO -22C AT 500MB, 0 TO -4C AT 700MB). THIS THERMODYNAMIC SETTING RESULTED IN A LITTLE BIT OF CONVECTIVE INSTABILITY WITH SBCAPE AROUND A COUPLE HUNDRED J/KG. THERE WILL BE LOOSELY ORGANIZED SHOWERS AND EMBEDDED THUNDER MOVING SOUTHEAST FROM THE CO/NE/KS TRI-BORDER REGION TO WESTERN/CENTRAL KANSAS LATE TONIGHT. MID LEVEL COLD ADVECTION AND DEEP TROPOSPHERIC ASCENT AHEAD OF THE WAVE WILL AID IN SUSTAINING SHOWER AND THUNDER ACTIVITY THROUGH THE NIGHT. AREAS CLOSER TO CENTRAL KANSAS (I.E. ELLIS COUNTY) WILL STAND A BETTER CHANCE AT MORE ORGANIZED CONVECTION AS REMNANT LOW LEVEL MOISTURE WAS HANGING AROUND AFTER THE TROUGH PASSAGE FROM EARLIER TODAY. POPS WERE RAISED TO 40 TO 50 PERCENT...ESPECIALLY IN THE NORTHEASTERN DDC FORECAST AREA (CLOSER TO CENTRAL KANSAS). SUBSIDENCE IN THE WAKE OF THE SHORTWAVE TROUGH WILL MOVE INTO WEST CENTRAL KANSAS DURING THE 09-12Z TIME FRAME...AND THE SHOWER ACTIVITY WILL MOVE INTO SOUTH CENTRAL KANSAS AND NORTHERN OKLAHOMA. AS FAR AS TEMPERATURES GO...COLD ADVECTION WILL BE RATHER WEAK AT THE SURFACE WITH SOME DOWNSLOPE MODIFICATION...SO LOWS TONIGHT AFTER THE SHOWERS MOVE THROUGH WILL ONLY BOTTOM OUT IN THE UPPER 30S TO LOWER 40S. ON SUNDAY...SUBSIDENCE WILL PREVAIL WITH WEAK SURFACE HIGH YIELDING LIGHT WINDS THROUGH THE DAY. HIGHS WERE LOWERED JUST A COUPLE DEGREES INTO THE UPPER 60S GIVEN THE SLIGHTLY COOLER LOWER TROPOSPHERE BEHIND THE WAVE. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 403 PM CDT SAT MAR 30 2013 A COLD CANADIAN HIGH PRESSURE WILL AGAIN INFLUENCE THE WEATHER FOR AT LEAST THE MONDAY THROUGH WEDNESDAY TIMEFRAME. BOTH THE GFS AND ECMWF ALLOW A SURFACE BACKDOOR COLD FRONT TO SLIDE INTO WESTERN KANSAS SUNDAY NIGHT INTO EARLY MONDAY, BRINGING EASTERLY UPSLOPE WINDS THAT REMAIN ESTABLISHED THROUGH ABOUT WEDNESDAY MORNING. ADDITIONALLY, THE MODELS HAVE BEEN VERY CONSISTENT NOW FOR SEVERAL DAYS IN DEVELOPING A PROGRESSIVE TROUGH OVER THE WESTERN UNITED STATES WHICH DIGS INTO THE SOUTHERN ROCKIES BY TUESDAY AND TUESDAY NIGHT. THE RESULT WILL BE AN INCREASING CHANCE OF PRECIPITATION (EITHER RAIN/SNOW OR BOTH) FROM THE LATE MONDAY TIMEFRAME THROUGH TUESDAY AND WEDNESDAY MORNING. WITH THE COOL AND EASTERLY UPSLOPE EXPECTED BY MONDAY, TEMPERATURES WILL DROP 20 TO 30 DEGREES FROM SUNDAY AFTERNOON`S LOW 70`S. STRATUS WILL LIKELY IMPEDE INSOLATION SIGNIFICANTLY DURING THE TIMEFRAME BASED ON MODEL 925-850 MB RELATIVE HUMIDITY FIELDS. THROUGH THE DAY THE LAYER BECOME THICKER WITH TIME, WHICH MIGHT SUGGEST SOME LIGHT FOG OR EVEN DRIZZLE POTENTIAL THROUGH THE OVERNIGHT SUNDAY WITH TEMPERATURES REMAINING ABOVE FREEZING. SNOW PRECIPITATION TYPE REALLY WON`T BE DEPENDENT ON THE ARRIVAL OF COLD ENOUGH AIR ALOFT, BUT RATHER THE MOISTENING UP OF A DEEP ENOUGH SATURATED LAYER THROUGH THE QG-FRONTOGENESIS/ISENTROPIC LIFTING PROCESS ON TUESDAY. THE LATEST ECMWF MODEL RUN DEPICT THE HEAVIER SNOWFALL TO OCCUR FARTHER SOUTHWEST OVER SOUTHEAST COLORADO AND THE PANHANDLES, THAN THE GFS MODEL RUNS WHICH FORECASTS HEAVY SNOW ACROSS SOUTHWEST KANSAS. AT A MINIMUM THE MODEL TRENDS LEND CONFIDENCE TO HIGHER CHANCES FOR PRECIPITATION DURING THIS TIMEFRAME, AND INFLUENCING COOLER TEMPERATURES FOR WEDNESDAY. THE REMAINDER OF THE WEEK SHOULD BRING A WARMING TREND BACK TOWARD CLIMATOLOGY AS UPPER LEVEL RIDGING TO FLAT ZONAL UPPER LEVEL FLOW AND SOUTHERLY SURFACE WINDS BECOME RE-ESTABLISHED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 600 PM CDT SAT MAR 30 2013 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH LATE THIS EVENING. A COLD FRONT IS THEN EXPECTED TO PUSH SOUTHEAST ACROSS WESTERN KANSAS LATE TONIGHT. SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE ALONG AND BEHIND THE FRONT AS IT MOVES THROUGH OVERNIGHT. MVFR CIGS/VSBYS MAY OCCUR IN ASSOCIATION WITH ANY POTENTIAL STORMS. OTHERWISE, EXPECT VFR CONDITIONS TO CONTINUE/REDEVELOP EARLY SUNDAY MORNING. LIGHT NORTHERLY WINDS THIS EVENING WILL INCREASE UP TO AROUND 15 TO 25KT LATE TONIGHT AS THE AFOREMENTIONED COLD FRONT PUSHES THROUGH WESTERN KANSAS. THE WINDS WILL SUBSIDE SUNDAY MORNING AS SURFACE HIGH PRESSURE BEGINS TO PUSH SOUTHEAST INTO THE WESTERN HIGH PLAINS. && .PRELIMINARY POINT TEMPS/POPS... DDC 40 68 35 45 / 40 10 40 40 GCK 38 68 35 44 / 40 10 30 40 EHA 41 68 40 44 / 30 10 30 40 LBL 41 68 42 45 / 30 10 30 40 HYS 38 67 34 44 / 50 10 40 40 P28 47 69 40 46 / 40 10 50 50 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...RUSSELL AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
914 AM CDT FRI MAR 29 2013 .UPDATE... ISSUED AT 901 AM CDT FRI MAR 29 2013 NO MAJOR UPDATES TO THE FORECAST. INTITIALIZED FORECAST GRIDS WITH 900 AM OBSERVATIONS. GARGAN && .SHORT TERM AND LONG TERM...(TODAY THROUGH THURSDAY) ISSUED AT 414 AM CDT FRI MAR 29 2013 MOST RECENT SHORTWAVE TROUGH AT 08Z EXTENDING FROM IA INTO KS IS MOVING SOUTHEAST AND WILL EXIT THE CWA EARLY THIS MORNING. THIS WAVE IN CONJUNCTION WITH ISENTROPIC LIFT NORTH OF THE STATIONARY BOUNDARY TO THE SOUTH HAS RESULTED IN NUMEROUS ELEVATED SHOWERS AND THUNDERSTORMS PRIMARILY SOUTH OF I 70. AS THE WAVE AND LIFT SHIFT SOUTHEAST AND MUCH DRIER AIR ALOFT OVERSPREADS THE AREA...PRECIP CHANCES WILL DIMINISH BY SUNRISE LEAVING A DRY FCST ACROSS THE COUNTY WARNING AREA FOR THE REMAINDER OF THE DAY. CLOUDS WILL ALSO DECREASE OVER THE SOUTHERN AREA EARLY LEAVING MOSTLY SUNNY SKIES MOST AREAS. HAVE THEREFORE BUMPED UP HIGHS FOR TODAY INTO THE MIDDLE TO UPPER 60S ALL AREAS. AS THE LLVL FLOW VEERS TONIGHT AND BECOMES MORE SOUTH/SOUTHWESTERLY...MOISTURE WILL ONCE AGAIN SURGE BACK TO THE NORTH...MAINLY FROM LATE EVENING THROUGH THE MORNING HOURS ON SATURDAY. THE BETTER FOCUS FOR FORCING/CONVERGENCE AND ISENTROPIC LIFT WILL OCCUR ACROSS PRIMARILY THE NORTHERN CWA AND HAVE MAINTAINED HIGHER END CHANCE POPS IN THIS AREA...THEN DECREASED SOUTHWARD. AS THE NEXT FRONT MOVES SOUTHEAST ACROSS THE CWA ON SATURDAY...THE AXIS OF HIGHER CAPE/INSTABILITY WILL SET UP ACROSS THE SOUTHEAST PORTIONS OF THE CWA IN THE AFTERNOON...PRIMARILY SOUTH AND EAST OF THE TURNPIKE. IF INHIBITION IS ERODED...STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE IN THIS AREA INTO THE EVENING HOURS BEFORE DECREASING AND EXITING THE SOUTHEAST CORNER BY MIDNIGHT. UP TO QUARTER SIZE HAIL AND STRONG GUSTY WINDS WOULD BE THE PRIMARY THREAT WITH THE STRONGER CELLS. SUNDAY IS STILL LOOKING DRY AHEAD OF THE NEXT...MUCH STRONGER COLD FRONT ON MONDAY. A WEDGE OF WARM AIR WILL STILL RESIDE ACROSS THE CWA OUT AHEAD OF THIS FRONT AND HAVE THEREFORE INCREASED SUNDAYS HIGH TEMPS INTO THE MIDDLE TO UPPER 60S. AS THE FRONT THEN TRAVERSES THE CWA FROM NORTH TO SOUTH...AT LEAST SCATTERED POST FRONTAL RAIN SHOULD DEVELOP AND MAY MIX WITH AND/OR CHANGEOVER TO ALL SNOW LATE SUNDAY NIGHT AND MONDAY BEFORE ENDING BY AFTERNOON. ANY SNOWFALL ACCUMULATIONS AT THIS POINT APPEAR TO BE GENERALLY LESS THAN AN INCH. EITHER WAY...MUCH COLDER CONDITIONS WITH HIGHS IN THE UPPER 30S TO LOW 40S ARE IN STORE FOR THE AREA ON MONDAY. THE AREA SHOULD GRADUALLY TRANSITION FROM COOLER NORTHWEST FLOW ALOFT TO A MORE ZONAL PATTERN THROUGH THE WEEK RESULTING IN MODERATING TEMPERATURES. HIGHS SHOULD RISE INTO THE 50S BY WEDNESDAY...THEN THE 60S BY THURSDAY. WILL MAINTAIN A DRY FCST THROUGH THE REMAINDER OF THE WEEK. 63 && .AVIATION... 11Z WATER VAPOR IMAGERY SHOWS THE WEAK UPPER WAVE BEGINNING TO PASS TO THE EAST. WITH THE RAP AND NAM SHOWING ISENTROPIC LIFT DIMINISHING...THINK ELEVATED SHOWERS WILL CONTINUE TO MOVE OFF TO THE EAST. MODELS DO NOT SHOW THE MOISTURE ADVECTION AND ISENTROPIC LIFT RETURNING UNTIL AFTER 02Z SAT. UNTIL THEN EXPECT VFR CONDITIONS DUE TO A LACK OF STRONG FORCING AND THE BOUNDARY REMAINING TO THE SOUTH AND WEST. UNCERTAINTY IN LOCATION OF PRECIP OVERNIGHT PRELUDES ANY MENTION OTHER THAN A VCSH ONCE THE 850 WINDS VEER AROUND TO THE SOUTHWEST AND BEGIN TO LIFT MOISTURE BACK INTO NORTHEAST KS LATE THIS EVENING. WOLTERS && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GARGAN SHORT TERM...63 LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1107 AM CDT FRI MAR 29 2013 .DISCUSSION... SEE PREV DISCUSSION. && .AVIATION... 11Z WATER VAPOR IMAGERY SHOWS THE WEAK UPPER WAVE BEGINNING TO PASS TO THE EAST. WITH THE RAP AND NAM SHOWING ISENTROPIC LIFT DIMINISHING...THINK ELEVATED SHOWERS WILL CONTINUE TO MOVE OFF TO THE EAST. MODELS DO NOT SHOW THE MOISTURE ADVECTION AND ISENTROPIC LIFT RETURNING UNTIL AFTER 02Z SAT. UNTIL THEN EXPECT VFR CONDITIONS DUE TO A LACK OF STRONG FORCING AND THE BOUNDARY REMAINING TO THE SOUTH AND WEST. UNCERTAINTY IN LOCATION OF PRECIP OVERNIGHT PRELUDES ANY MENTION OTHER THAN A VCSH ONCE THE 850 WINDS VEER AROUND TO THE SOUTHWEST AND BEGIN TO LIFT MOISTURE BACK INTO NORTHEAST KS LATE THIS EVENING. WOLTERS && .PREV DISCUSSION... /414 AM CDT FRI MAR 29 2013/ MOST RECENT SHORTWAVE TROUGH AT 08Z EXTENDING FROM IA INTO KS IS MOVING SOUTHEAST AND WILL EXIT THE CWA EARLY THIS MORNING. THIS WAVE IN CONJUNCTION WITH ISENTROPIC LIFT NORTH OF THE STATIONARY BOUNDARY TO THE SOUTH HAS RESULTED IN NUMEROUS ELEVATED SHOWERS AND THUNDERSTORMS PRIMARILY SOUTH OF I 70. AS THE WAVE AND LIFT SHIFT SOUTHEAST AND MUCH DRIER AIR ALOFT OVERSPREADS THE AREA...PRECIP CHANCES WILL DIMINISH BY SUNRISE LEAVING A DRY FCST ACROSS THE COUNTY WARNING AREA FOR THE REMAINDER OF THE DAY. CLOUDS WILL ALSO DECREASE OVER THE SOUTHERN AREA EARLY LEAVING MOSTLY SUNNY SKIES MOST AREAS. HAVE THEREFORE BUMPED UP HIGHS FOR TODAY INTO THE MIDDLE TO UPPER 60S ALL AREAS. AS THE LLVL FLOW VEERS TONIGHT AND BECOMES MORE SOUTH/SOUTHWESTERLY...MOISTURE WILL ONCE AGAIN SURGE BACK TO THE NORTH...MAINLY FROM LATE EVENING THROUGH THE MORNING HOURS ON SATURDAY. THE BETTER FOCUS FOR FORCING/CONVERGENCE AND ISENTROPIC LIFT WILL OCCUR ACROSS PRIMARILY THE NORTHERN CWA AND HAVE MAINTAINED HIGHER END CHANCE POPS IN THIS AREA...THEN DECREASED SOUTHWARD. AS THE NEXT FRONT MOVES SOUTHEAST ACROSS THE CWA ON SATURDAY...THE AXIS OF HIGHER CAPE/INSTABILITY WILL SET UP ACROSS THE SOUTHEAST PORTIONS OF THE CWA IN THE AFTERNOON...PRIMARILY SOUTH AND EAST OF THE TURNPIKE. IF INHIBITION IS ERODED...STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE IN THIS AREA INTO THE EVENING HOURS BEFORE DECREASING AND EXITING THE SOUTHEAST CORNER BY MIDNIGHT. UP TO QUARTER SIZE HAIL AND STRONG GUSTY WINDS WOULD BE THE PRIMARY THREAT WITH THE STRONGER CELLS. SUNDAY IS STILL LOOKING DRY AHEAD OF THE NEXT...MUCH STRONGER COLD FRONT ON MONDAY. A WEDGE OF WARM AIR WILL STILL RESIDE ACROSS THE CWA OUT AHEAD OF THIS FRONT AND HAVE THEREFORE INCREASED SUNDAYS HIGH TEMPS INTO THE MIDDLE TO UPPER 60S. AS THE FRONT THEN TRAVERSES THE CWA FROM NORTH TO SOUTH...AT LEAST SCATTERED POST FRONTAL RAIN SHOULD DEVELOP AND MAY MIX WITH AND/OR CHANGEOVER TO ALL SNOW LATE SUNDAY NIGHT AND MONDAY BEFORE ENDING BY AFTERNOON. ANY SNOWFALL ACCUMULATIONS AT THIS POINT APPEAR TO BE GENERALLY LESS THAN AN INCH. EITHER WAY...MUCH COLDER CONDITIONS WITH HIGHS IN THE UPPER 30S TO LOW 40S ARE IN STORE FOR THE AREA ON MONDAY. THE AREA SHOULD GRADUALLY TRANSITION FROM COOLER NORTHWEST FLOW ALOFT TO A MORE ZONAL PATTERN THROUGH THE WEEK RESULTING IN MODERATING TEMPERATURES. HIGHS SHOULD RISE INTO THE 50S BY WEDNESDAY...THEN THE 60S BY THURSDAY. WILL MAINTAIN A DRY FCST THROUGH THE REMAINDER OF THE WEEK. 63 && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
405 AM CDT SUN MAR 31 2013 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 406 AM CDT SUN MAR 31 2013 CONSIDERED A DENSE FOG ADVISORY FOR WESTERN PORTIONS OF SOUTHEAST MISSOURI DUE TO KPOF REPORTING 1/2 MILE OR LESS...BUT IT SEEMS TO BE IMPROVING A BIT IN THE LAST HOUR AND WE HAVE LITTLE CLUE HOW WIDESPREAD IT IS. WILL KEEP AN EYE ON IT...BUT FOR NOW WILL JUST LET IT BE. WEAK ECHOES FOR LIGHT RAIN HAVE JUST ABOUT PUSHED EAST OF THE EVANSVILLE TRI STATE...BUT THERE MAY BE JUST A BIT LINGERING IN THE KOWB AREA. THIS SHOULD COME TO AN END SHORTLY. OF GREATER CONCERN IS THE AREA OF SHOWERS AND THUNDERSTORMS MOVING EAST SOUTHEAST ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI. HAD TO LEAN ON THE HRRR MODEL SIMULATED REFLECTIVITY TO REPRESENT THIS IN THE GRIDS. IN GENERAL WOULD EXPECT THE AREA TO WEAKEN AS IT MOVES INTO OUR REGION JUST AFTER SUNRISE...SO WILL HAVE 20-30 POPS FOR NOW...GENERALLY SWEEPING ACROSS OUR SOUTHWEST HALF 14Z- 20Z. THIS WEAKENING TREND IS SUPPORTED BY THE 06Z NAM...WHICH KEEPS ANY INSTABILITY TO OUR WEST AND SOUTHWEST. WILL HAVE TO KEEP A CLOSE EYE ON THIS SITUATION AS WELL AND BE PREPARED TO UPDATE IF/WHEN IT BECOMES NECESSARY. TEMPERATURES EARLY THIS MORNING ARE NEARLY STEADY...SO WE WILL HAVE A MILD START TO THE DAY...WHICH IS GOOD BECAUSE THE LOW CLOUDS/FOG AND EVENTUALLY SOME SHOWERS WILL DELAY WARMING THROUGH THE MORNING. TRIED TO CAPTURE THIS TREND IN THE TEMPERATURE GRIDS...BUT WE SHOULD JUMP UP WELL INTO THE 60S WITH SOME SUNSHINE THIS AFTERNOON. STAYED CLOSE TO CONSENSUS. LIKE THE 00Z AND 06Z NAM WITH THE REAL COLD FRONT/SURFACE HIGH SURGE THROUGH THE AREA LATE TONIGHT AND MONDAY...AS IT SHOULD HANDLE THE SHALLOW COLD AIRMASS BETTER THAN THE LESSER RESOLVED GFS. THE NAM DOES GENERATE SOME VERY MEAGER QPF OVER THE EVANSVILLE TRI STATE TONIGHT WITH THE INITIAL WIND SHIFT...BUT THE GFS IS DRY. DECIDED TO MENTION SOME SPRINKLES IN THAT AREA THROUGH THE NIGHT...BUT DID NOT INTRODUCE A MEASURABLE POP. CONSENSUS OF GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON TEMPERATURES TONIGHT. TEMPERATURES ONLY FALL INTO THE UPPER 30S IN THE NORTH...SO LITTLE CHANCE OF FLURRIES WITH THE SPRINKLES TONIGHT. FOR MONDAY...THE MODELS CONTINUE TO TREND DRIER AND DRIER FOR OUR AREA. SIMILAR TO TONIGHT...DECIDED TO JUST PLASTER A CHANCE OF SPRINKLES ACROSS THE ENTIRE AREA THROUGH THE DAY...IN LIEU OF A VERY SMALL MEASURABLE POP. TEMPERATURES WILL SUPPORT ALL LIQUID THROUGH THE DAY. FIGURE WITH THE SURGE CONSISTENTLY ADVERTISED IN THE NAM RUNS...THAT TEMPERATURES WILL BE COOLER THAN MOST GUIDANCE INDICATES. STAYED ON THE LOW SIDE OF GUIDANCE CLOSER TO THE NAM/MET...BUT THAT MAY NOT BE COOL ENOUGH. MONDAY NIGHT WILL BE DRY...BUT WE WILL REMAIN IN CYCLONIC WEST NORTHWEST FLOW ALOFT...SO CANNOT RULE OUT SOME LIGHT PRECIPITATION...ESPECIALLY OVER OUR SOUTHWEST MONDAY NIGHT INTO TUESDAY. THE GFS IS THE MOST AGGRESSIVE IN GENERATING LIGHT QPF WITH SOME FRONTOGENETIC FORCING IN THE 850-700MB LAYER IN THE FAR SOUTHWEST. INTRODUCED SOME VERY SMALL POPS NEAR THE ARKANSAS BORDER AND THE BOOT HEEL REGION JUST TO BE SAFE. LATELY...IF THERE IS ANY CHANCE OF US GETTING WET IT SEEMS TO HAPPEN. TEMPERATURES IN THAT AREA SHOULD BE NO LOWER THAN THE MIDDLE 30S...SO KEPT THIS ALL RAIN AS WELL. CONSENSUS TEMPERATURES LOOKED FINE MONDAY NIGHT AND TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 406 AM CDT SUN MAR 31 2013 THIS EXTENDED PERIOD FOR THIS FORECAST ISSUANCE WILL SERVE AS THE TRANSITION OF EXTREMES IN TEMPERATURE FROM NEAR RECORD LOWS WEDNESDAY MORNING TO ABOVE NORMAL /MIDDLE 60S/ HIGHS NEXT WEEKEND. GIVEN THE BELOW NORMAL TEMPERATURES WE HAVE BEEN EXPERIENCING IN MARCH...TEMPERATURES AT OR ABOVE NORMAL WILL BE A WELCOME CHANGE. THE ONLY WEATHER MAKER OF CONSEQUENCE WILL OCCUR THURSDAY/THURSDAY NIGHT. ANY MEASURABLE POPS AND WEATHER /GENERALLY SLIGHT IN CATEGORY/ WILL BE LIMITED TO WEST KENTUCKY AND A SMALL PART OF THE SOUTHEAST MISSOURI BOOTHILL. THE SOURCE REGION FOR THIS SYSTEM IS THE CLOSED LOW CURRENTLY OFF THE CALIFORNIA COAST. THIS FEATURE IS EXPECTED TO PUSH TOWARD THE CENTRAL ROCKIES AND DIVE EAST-SOUTHEAST INTO THE LOWER MISSISSIPPI VALLEY. DURING THE PAST 3-4 DAYS...THE NORTHERN EDGE OF THIS CLOSED LOW/WAVE HAS BEEN FORECAST BY THE GFS/ECMWF/GEM GUIDANCE TO SKIRT ALONG THE SOUTHERN BORDER OF THE WFO PAH FORECAST AREA. THERE HAS BEEN ENOUGH MODEL RUNS TO STILL INDICATE THAT VERY FEW LOCATIONS WILL SEE ANY RAIN...IF ANY...ON THURSDAY. THE MAIN IMPACT WILL BE CLOUD COVER...WITH A SHARP DEMARCATION LINE ON THE NORTHERN EDGE OF THE DEFORMATION ZONE ASSOCIATED WITH THE LOW/WAVE. NORTHEAST WINDS DURING THIS TIME PERIOD MAY TEMPER HIGHS SOMEWHAT. WITH HIGH PRESSURE DOMINATING THE REGION THROUGH MOST OF THE PERIOD...CLOUD COVER WILL BE MINIMAL OUTSIDE OF THE DISTURBANCE ON THURSDAY. THIS WILL SET THE STAGE FOR GOOD INSOLATION/DRY AIR ADVECTION AND EVAPORATION. A MANUAL UPWARD ADJUSTMENT WAS MADE TO THE MAX TEMPERATURES FROM FRIDAY THROUGH SUNDAY TO ACCOUNT FOR A LARGER DIURNAL RANGE /25-27 DEGREES F/IN TEMPERATURES WITH THE DRIER AIR IN PLACE ACROSS THE WFO PAH FORECAST AREA. AS A SIDE NOTE...MIN FORECAST TEMPERATURES WEDNESDAY MORNING LOOK LIKE THEY MAY BE ONE TO TWO DEGREES HIGHER THAN THE RECORD TEMPERATURES ON THE BOOKS. SUBTLE MICRO-CLIMATE CHANGES AROUND THE OBSERVATION SITES WILL DETERMINE WHETHER ANY RECORDS ARE TIED OR SET WEDNESDAY MORNING. && .AVIATION... ISSUED AT 1223 AM CDT SUN MAR 31 2013 RAIN WILL CONTINUE TO SHIFT EAST OF THE REGION OVERNIGHT. LEFTOVER LOW LEVEL MOISTURE WILL RESULT IN IFR CONDITIONS DUE TO BOTH FOG AND LOW CLOUDS. THE GREATEST POTENTIAL FOR DENSE FOG APPEARS TO BE WEST OF THE MISSISSIPPI RIVER. THE FOG AND LOW CLOUDS WILL GRADUALLY CLEAR OUT SUNDAY MORNING...LEAVING BEHIND VFR CONDITIONS BY AFTERNOON. LIGHT AND VARIABLE WINDS TONIGHT WILL BECOME W/NW 5 TO 10 KNOTS SUNDAY. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...DRS LONG TERM...SMITH AVIATION...RJP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 AM EDT SUN MAR 31 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 453 PM EDT SAT MAR 30 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE OVER THE FAR WRN CONUS INTO WRN CANADA WHILE DOWNSTREAM TROF WAS AMPLIFYING S THRU CNTRL CANADA INTO THE NCNTRL CONUS. WITHIN THE DEEPENING TROF...A SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES HAS BROUGHT A BAND OF PCPN TO UPPER MI TODAY. PCPN WAS MAINLY RAIN OVER THE W...BUT MIXED WITH/CHANGED TO SNOW OVER THE CNTRL/E. SNOW WAS MDT/HVY ACROSS IRON/DICKINSON COUNTIES WHERE A FEW INCHES OF WET SNOW ACCUMULATION HAS BEEN REPORTED. THE HEAVIER SNOW IS NOW STREAKING E TOWARD LUCE COUNTY. BACKEDGE OF THE MAIN PCPN AREA WAS OVER CNTRL UPPER MI AS OF 20Z. WITH DEPARTURE OF THIS AREA OF PCPN...ATTENTION IN THE SHORT TERM SHIFTS TO SHORTWAVE DIGGING SHARPLY INTO THE UPPER GREAT LAKES LATE TONIGHT/SUN AND THE INCREASINGLY COLDER AIR IT WILL BRING. INCORPORATING EXTRAPOLATION FOR ENDING PCPN...EXPECT STEADIER PCPN TO EXIT THE ERN FCST AREA AROUND 03Z WITH ALL OF THE AREA DRY BY 06Z. MAY SEE AN INCH OR SO OF WET SNOW OVER THE INTERIOR E DURING THE LATE AFTN. LOW CLOUDS AND FOG WERE PRESENT EARLY TODAY BEHIND THE PCPN AREA IN MN...AND WILL PROBABLY SEE SOME OF THAT AND PERHAPS SOME -DZ IN MAINLY AREAS THAT SEE UPSLOPING WITH A W WIND FOR A FEW HRS AFTER PCPN ENDS AND BEFORE THE ONSET OF CAA OVERNIGHT INCREASES LOW-LEVEL MIXING. BY 12Z...850MB TEMPS ARE PROGGED AT -8/-9C OVER WRN LAKE SUPERIOR. WHILE THAT IS SHY OF THE THRESHOLD FOR LES GIVEN WATER TEMPS AROUND 1C...SRN EDGE OF DEEP LAYER FORCING ASSOCIATED WITH APPROACHING SHORTWAVE AND PRESENCE OF CYCLONIC FLOW MAY GENERATE SOME LAKE ENHANCED -SHSN OVER NW UPPER MI LATE IN THE NIGHT. DURING THE DAY SUN...SHORTWAVE DIGS S ACROSS THE UPPER GREAT LAKES...BRINGING 100-120M HEIGHT FALLS AT 500MB. ALTHOUGH BEST DEEP LAYER FORCING PASSES N AND NE OF UPPER MI...DEEP CYCLONIC FLOW AND SUFFICIENT INCREASE IN MOISTURE DEPTH TO AROUND 10KFT SUGGESTS SCT TO NMRS -SHSN ARE A GOOD BET. LATE MAR SOLAR INSOLATION WILL ADD A DIURNAL COMPONENT TO -SHSN COVERAGE OVER THE INTERIOR WHILE DISRUPTING NORMAL LAKE EFFECT PROCESSES THAT WOULD BE GETTING UNDERWAY OVER LAKE SUPERIOR AS 850MB TEMPS FALL TOWARD -14C IN THE AFTN. ALTHOUGH COLUMN BECOMES MORE SUPPORTIVE OF SNOW AS PTYPE AS THE DAY PROGRESSES...DAYTIME HEATING SHOULD RESULT IN MIX WITH -SHRA INTO THE MID AFTN OVER THE SCNTRL. WINDS MAY APPROACH ADVY CRITERIA OVER THE KEWEENAW...BUT WITH MIXED LAYER WINDS LOW/MID 30KT AT MOST AND ONLY MODEST PRES RISES APPROACHING FROM THE NW...DO NOT ANTICIPATE WIND ADVY BEING NEEDED AT THIS POINT. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 453 PM EDT SAT MAR 30 2013 CONTINUE TO SEE GOOD AGREEMENT FROM GFS/ECMWF/GEM-NH IN OVERALL LARGER SCALE PATTERN FOR THE LONG TERM. DEEP AND COLD TROUGHING INITIALLY IN PLACE LEADS TO A PERIOD OF LAKE ENHANCED SNOW FOR SNOWBELTS FAVORED BY NORTHWEST WINDS SUNDAY NIGHT THROUGH TUESDAY MORNING. FOCUSED IN ON MORE OF THE DETAILS THIS GO AROUND. WAVE THAT MOVES THROUGH TO BRING IN THE TROUGHING ON SUNDAY NIGHT PRETTY SHARP UPSTREAM THIS MORNING OVER NORTHERN MANITOBA INTO NINAVUT. WENT WITH MODELS THAT WERE SHARPER WITH H5 WAVE AND RESULTING SFC TROUGH DROPPING ACROSS LK SUPERIOR LATE SUNDAY AFTN INTO SUNDAY EVENING. SOUNDINGS DURING THAT TIME INDICATE MORE OF A WIDESPREAD SNOW JUST IN WAKE OF FRONT...ALONG WITH PUSH OF NORTH WINDS TO AROUND 40 MPH. EXPANDED POPS OVER MUCH OF THE NORTH HALF OF CWA SUNDAY EVENING. SNOWFALL RATES MAY EXCEED 1"/HOUR FOR A COUPLE HOURS AS THIS BAND OF SNOW MOVES THROUGH. BY MIDNIGHT...MODELS INDICATE WIDESPREAD DEEPER H8-H7 MOISTURE DEPARTS LEAVING MOST OF THE SNOW SET UP OVER HIGHER TERRAIN OF WEST AND NCNTRL CWA AND ALSO FOR SNOWBELTS FROM MUNISING TO NEWBERRY. LAKE ENHANCED SNOW THAT OCCURS FOR THOSE SNOWBELTS LATER SUNDAY NIGHT INTO MONDAY MAY BE HEAVY AT TIMES AS SOUNDINGS INDICATE MOISTURE THROUGH H8 AND INVERSION HEIGHTS UP TO 10KFT. OVER-WATER INSTABILITY IS SUFFICIENT AS H85 TEMPS ARE AROUND -16C. AT FIRST GLANCE SEEMS LIKE LAKE EFFECT SNOW WATCH MAY BE IN ORDER. THERE ARE A COUPLE NEGATIVE FACTORS THOUGH THAT PROHIBITED ISSUANCE OF WATCH. FIRST OF WHICH IS DRYING NOTED BLO 5KFT LEADING TO MORE OF AN INVERTED-V LOOK TO SOUNDING...ESPECIALLY OVERNIGHT SUNDAY NIGHT INTO MONDAY. SECOND NEGATIVE IS SHEAR IN THE MOIST CONVECTIVE LAYER AT LEAST TO START OUT...BUT THIS DOES EASE LATE SUNDAY NIGHT THOUGH BLYR WINDS STAY UP TO 30 KTS FROM THE NORTHWEST. BEST SHOT AT HEAVIER SNOW WOULD BE THROUGH MID-LATE MORNING ON MONDAY AS DAYTIME HEATING/HIGHER SUN ANGLE WILL ACT TO DISRUPT SNOW SHOWERS AS THE DAY GOES ON. LAKE EFFECT SNOW SHOWERS MAY INCREASE AGAIN MONDAY NIGHT. DUE TO COMBO OF THE LAKE EFFECT SNOWS AND BLOWING SNOW...LIKELY WILL NEED ADVISORY HEADLINES INTO MONDAY NIGHT AND TUESDAY MORNING. SINCE THERE IS NOT MUCH BLOCKINESS DOWNSTREAM...DEEP TROUGH WILL REMAIN PROGRESSIVE WITH RISING HEIGHTS DEVELOPING OVER UPPER LAKES AS EARLY AS TUESDAY. SUFFICIENTLY COLD AND MOIST ENOUGH FOR LK EFFECT BUT LARGER SCALE NEGATIVES SHOULD RESULT IN DIMINISHING TREND TO LK EFFECT BY TUESDAY AFTN. POPS REFLECTED THIS FOR MOST PART...JUST NEEDED SOME MINOR TWEAKS. AFTER PARTIAL CLEARING AND WARMER CONDITIONS FOR WEDNESDAY ANOTHER SHORTWAVE TROUGH THEN SWINGS ACROSS MANITOBA AND NORTHERN ONTARIO WEDNESDAY NIGHT AND THURSDAY. ASSOCIATED COLD FRONT MOVES ACROSS UPPER LAKES ON THURSDAY. DPROG/DT FROM EARLIER GFS/ECMWF RUNS INDICATED A SLOWER TREND WITH SHORTWAVE POINTING TO MOST OF PRECIPITATION FROM THE SYSTEM TAKING PLACE ON THURSDAY OVER UPPER MICHIGAN. 12Z GFS REALLY SPED UP AND SEEMS OUT OF PLACE NOW WITH PCPN TIMING. 1000-500MB AND 1000-850MB THICKNESSES INDICATE MIX OF RAIN/SNOW. LIMITED MOISTURE WILL KEEP AMOUNTS LIGHT. COOLER AND DRY IN WAKE OF COLD FRONT INTO FRIDAY. QUESTIONS INCREASE FOR NEXT WEEKEND. GOOD BET THAT UPPER LAKES WILL BE ON THE SOUTHERN EDGE OF STRONGER JET STREAM RIDING ALONG SOUTHERN TIER OF CANADA. AS MID-LEVEL FLOW BECOMES MORE WESTERLY MODELS INDICATE SHORTWAVE TROUGH AND SFC-H85 LOWS VCNTY OF NORTHERN PLAINS INTO WESTERN GREAT LAKES BY 12Z SATURDAY. POOR CONSISTENCY ON WHERE SFC-H85 LOWS SET UP THOUGH. LATEST ECMWF/GFS CONTINUE TO INDICATE FARTHER NORTH LOW WITH QPF INTO UPPER LAKES BY NEXT SATURDAY WHILE EARLIER RUNS KEPT MOST OF QPF TO SOUTH. 1000-500MB AND 1000-850MB THICKNESSES AT OR ABOVE 540DAM AND 1305M AND H85 TEMPS OVER 0C INTO WESTERN CWA INDICATE MIX OF RAIN AND SNOW. CONSENSUS OF MODELS CAME UP WITH HIGHER CHANCE POPS WHICH WILL WORK IF THE NORTHERN TREND CONTINUES IN THE MODELS. JUST CANNOT SEEM TO SHAKE THIS COOLER AND ACTIVE WEATHER PATTERN AS WE HEAD INTO THE FIRST WEEK OF APRIL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 134 AM EDT SUN MAR 31 2013 ARRIVAL OF DRIER AIR SHOWN ON THE 00Z INL RAOB WILL RESULT IN VFR CONDITIONS EARLY THIS MRNG AT CMX/IWD AND A BREAKUP OF THE FOG/ST/IFR CONDITIONS NOW IMPACTING SAW BY 09Z. EXPECT INCREASING POTENTIAL OF -SHSN AT WRN TAF SITES BY LATE MRNG AS CONDITIONS FALL TO MVFR AT CMX/IWD WITH ARRIVAL OF NEXT DISTURBANCE. GUSTY WNW WINDS WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE LATE THIS MORNING. WNW AND COLD ADVECTION BEHIND FRONT WILL BRING A CHANCE OF -SHSN SUNDAY AFTERNOON AT KSAW ALONG WITH MVFR CIGS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 453 PM EDT SAT MAR 30 2013 STRONGER DISTURBANCE MOVING INTO THE UPPER LAKES SUN WILL USHER COLDER AIR OVER LAKE SUPERIOR WHILE SFC LOW PRES DEEPENS TO THE E AND NE. THIS WILL RESULT IN STRENGTHENING NW WINDS ACROSS THE LAKE. IN FACT...NW GALES ARE EXPECTED TO DEVELOP OVER CNTRL AND ERN LAKE SUPERIOR SUN AFTN. UNDER SLOW MOVING WEATHER PATTERN WITH COLD UNSTABLE AIR OVER THE LAKE...THE GALES WILL LIKELY CONTINUE INTO TUE. FREEZING SPRAY WILL ALSO DEVELOP SUN NIGHT AND LINGER INTO TUE AS UNSEASONABLY COLD AIR SETTLES OVER THE AREA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT TUESDAY FOR LSZ264>267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 PM EDT MONDAY FOR LSZ244-245-249>251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...KC MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
225 AM CDT SUN MAR 31 2013 .SHORT TERM...(EASTER SUNDAY) ISSUED AT 224 AM CDT SUN MAR 31 2013 FORECAST HAS CHANGED TODAY GIVEN CURRENT CONDITIONS AND LATEST SHORT RANGE MODEL GUIDANCE. SHORTWAVE ENERGY...EVIDENT ON LATEST WATER VAPOR IMAGERY...DROPPING SOUTHEAST FROM SOUTHERN NEBRASKA HAS LED TO A LARGE AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOPING ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI. LATEST RUC AND HRRR SHOW THIS AREA OF RAIN SHOWERS/STORMS EXPANDING AS EAST/SOUTHEAST THIS MORNING ACROSS CENTRAL MISSOURI AND THE OZARKS...PERHAPS GRAZING EAST CENTRAL MISSOURI AND SOUTHWEST ILLINOIS. WILL FINE TUNE POPS BEFORE FORECAST ISSUANCE BASED ON THE VERY LATEST RADAR TRENDS. THERE WILL OBVIOUSLY BE A SLOWER CLEARING TREND TO THE CLOUDS THANKS TO THIS SHORTWAVE...AND FEEL IT PRUDENT TO SIDE WITH SLIGHTLY COOLER MAV GUIDANCE FOR HIGH TEMPERATURES. TO COMPLICATE THE FORECAST EVEN FURTHER...MUCH OF THE EXPLICIT AND HIGH RESOLUTION MODEL GUIDANCE DEPICT SOME ISOLATED SHOWERS DEVELOPING ALONG A PREFRONTAL TROF THIS AFTERNOON AND EVENING FROM CENTRAL ILLINOIS TOWARD THE ST. LOUIS METRO AREA. SO HAVE INCLUDED SOME LOW CHANCE/ISOLATED POPS FOR THIS AS WELL. CVKING && .LONG TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 224 AM CDT SUN MAR 31 2013 (TONIGHT AND MONDAY) ARCTIC COLD FRONT EXPECTED TO MOVE SOUTH ACROSS THE CWA TONIGHT WITH NORTH WIND AND COLD ADVECTION TAKING CONTROL OF THE WEATHER FOR THE EARLY PART OF THE WORK WEEK. LATEST GUIDANCE CONTINUES TO DEPICT A BAND OF LIGHT POST FRONTAL PRECIPITATION AFFECTING MAINLY NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS SUNDAY NIGHT. THIS PRECIPITATION SHOULD WEAKEN AS IT PROGRESSES SOUTH MONDAY MORNING TO THE I-70 CORRIDOR. MAINTAINED RAIN/SNOW MIX...BUT DONT EXPECT ANY ACCUMULATION DUE TO WARM AIR AND GROUND TEMPERATURES. HAVE SIDED WITH COOLER MET GUIDANCE FOR TEMPERATURES. (TUESDAY THROUGH SATURDAY) SLOW WARMING TREND EXPECTED WITH HIGH PRESSURE MOVING EAST OF THE AREA BY LATE IN THE WEEK. HAVE KEPT FORECAST DRY AS GUIDANCE KEEPS CUTOFF LOW TO THE SOUTH OF THE AREA THURSDAY. CVKING && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 619 PM CDT SAT MAR 30 2013 COMPLEX WX FORECAST THRU THE NEXT 6 TO 12 HRS. RA WILL CONTINUE TO MOVE EWD AND SHUD BE AFFECTING ONLY KCPS BY THE TIME TAFS ARE VALID. CONDITIONS SHUD IMPROVE BRIEFLY BEHIND THE PRECIP...BUT SHUD FALL BACK INTO THE MVFR RANGE QUICKLY. LARGER FORECAST ISSUE FOR TONIGHT IS IF FG/ST WILL DEVELOP LATER TONIGHT. ATTM...KCOU HAS THE BEST POTENTIAL FOR IFR FG/ST DEVELOPING AND HAVE TRENDED TAF IN THAT DIRECTION. TOO MANY QUESTIONS REMAIN TO CHANGE THE FORECAST DRASTICALLY NOW. OTHERWISE...CONDITIONS SHUD IMPROVE QUICKLY SUN MORNING AS THE FNT DRIFTS S OF THE TERMINALS. WITH DEEP MIXING...HIGH BASED CU SHUD FORM DURING THE AFTERNOON HOURS AND MAY EVEN GENERATE PRECIP AFFECTING KUIN/KSUS/KCPS IN THE MID TO LATE AFTERNOON. SPECIFICS FOR KSTL...BULK OF PRECIP SHUD BE E OF THE TERMINAL BY 00Z WITH ONLY LIGHT PRECIP LINGERING. STILL SOME QUESTION REGARDING FG/ST DEVELOPMENT TONIGHT AND MADE ONLY MINOR CHANGES TO THE PREV TAF. CONDITIONS SHUD IMPROVE QUICKLY SUN MORNING AS THE FNT MOVES S OF THE TERMINAL. EXPECT HIGH BASED CU TO DEVELOP AND POSSIBLY A BRIEF SHRA SUN MID TO LATE AFTERNOON. TILLY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
319 AM EDT SUN MAR 31 2013 .SYNOPSIS... SOUTHERLY WINDS WILL BRING A MILD DAY TODAY BEFORE A COLD FRONT APPROACHES WITH SHOWERS DEVELOPING DURING THE AFTERNOON. THE COLD FRONT WILL USHER IN MUCH COLDER TEMPERATURES FOR THE FIRST HALF OF NEXT WEEK ALONG WITH SCATTERED SNOW SHOWERS AND HEAVIER LAKE EFFECT SNOW EAST OF THE LAKES. && .NEAR TERM /THROUGH TONIGHT/... LEAD SHORTWAVE CURRENTLY LIFTING INTO THE OHIO VALLEY. ASSOCIATED SHOWER ACTIVITY SHOWING UP ON UPSTREAM REGIONAL RADARS ACROSS WESTERN OHIO. THIS ACTIVITY IS IN DECENT AGREEMENT WITH LATEST HIGHER RESOLUTION HRRR RUN WHICH BRINGS THE LEADING EDGE OF SHOWERS ASSOCIATED WITH THIS SHORTWAVE INTO THE SOUTHERN TIER AND WESTERN FINGER LAKES BETWEEN 10 AM AND 2 PM. MODELS CONTINUING TO AGREE UPON THE SPLIT IN PRECIPITATION PATTERN BETWEEN THE SOUTHERN AREA OF PRECIPITATION ASSOCIATED WITH THE SHORTWAVE WORKING THROUGH THE OHIO VALLEY... AND THE NORTHERN STREAM SYSTEM WHICH LAGS BEHIND BY SEVERAL HOURS. THE NORTHERN SYSTEM WILL GENERATE ADDITIONAL WIDESPREAD SHOWER ACTIVITY BY EARLY TO MID AFTERNOON AS THE ASSOCIATED COLD FRONT APPROACHES THE REGION. SPC SREF PARAMETERS KEEP PRIMARY INSTABILITY AXIS WELL SOUTH OF THE AREA...THEREFORE NO NEED TO INCLUDE MENTION OF THUNDER IN THE FORECAST. AHEAD OF THE FRONT AND BEFORE THE RAIN ARRIVES...THE SOUTHERLY DOWNSLOPE FLOW COMBINED WITH WARMER TEMPERATURES ALOFT WILL ALLOW THE LAKE PLAINS TO WARM WELL INTO THE 50S. THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER AND EAST OF LAKE ONTARIO WILL TOP OUT IN THE MID TO UPPER 40S WITHOUT THE BENEFIT OF DOWNSLOPE FLOW AND AN EARLIER START TO THE RAIN. THE COLD FRONT WILL BE PUSH THROUGH EARLY TONIGHT. THE COLD AIR ADVECTION IS QUITE IMPRESSIVE BEHIND THE FRONT AND WE SHOULD SEE A CHANGE OVER TO SNOW OR A MIX BRIEFLY BEFORE THE PRECIPITATION DIMINISHES OVERNIGHT. WIND SHOULD PICK UP IN THE STRONG COLD AIR ADVECTIVE PATTERN...BUT SHOULD BE LIMITED TO GUSTS TO NEAR 30 MPH. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AN ARCTIC FRONT WILL CROSS THE REGION MONDAY MORNING WITH A CHANGEOVER FROM RAIN TO SNOW SHOWERS. 850MB TEMPS AT 12Z MONDAY WILL RANGE -12C AT THE NIAGARA RIVER TO -4C ACROSS CENTRAL NY...FALLING TO -12C TO -13C BY 00Z TUESDAY. THESE BOUNDARY LAYER TEMPS WILL BE SUFFICIENTLY COLD TO SUPPORT SOME LAKE EFFECT RESPONSE...BUT THE DESTABILIZING EFFECT OF EARLY APRIL SUNSHINE WILL DISRUPT ANY CONCENTRATED PRECIP...WILL HAVE LIKELY POPS FOR SMALL ACCUMULATIONS BUT DO NOT EXPECT ANY SIGNIFICANT ACCUMS UNTIL OVERNIGHT MONDAY NIGHT TO TUESDAY MORNING. WELL ALIGNED WESTERLY WINDS WILL FOCUS THE LAKE SNOW ON THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER AND ON THE TOP OF THE TUG HILL PLATEAU EAST OF LAKE ONTARIO. THE LONGER FETCH ALONG THE LENGTH OF LAKE ONTARIO WILL ALLOW THE TUG HILL TO APPRECIATE A BETTER CHANCE FOR SIGNIFICANT SNOW ACCUMULATION MONDAY NIGHT THROUGH EARLY WEDNESDAY. BOTH 00Z GFS AND ECMWF SHOW A WEAK SHORT WAVE CROSSING THE EASTERN GREAT LAKES ON WEDNESDAY WITH ONLY CHANCE POPS ASSOCIATED...LIMITING FACTORS AS THE LACK OF DEEP MOISTURE AND SURFACE HIGH PRESSURE STARTING TO BUILD IN FROM THE WEST. IT IS POSSIBLE THAT THIS LAKE EFFECT EVENT FROM MONDAY NIGHT TO WEDNESDAY MORNING MAY BRING WARNING CRITERIA SNOWS AS SUGGESTED BY RECENT CIPS ANALOGS OF THE TOP 15 MOST SIMILAR EVENTS. ACCUMULATIONS OF 6 TO 12 INCHES OR MORE MAY BE POSSIBLE UNDER THE MOST PERSISTENT BANDS. THE DURATION OF THE EVENT WILL LIKELY LEAD TO THE HIGHER ACCUMULATIONS...EVEN WITH THE LIMITING FACTOR OF LESS THAN OPTIMAL MOISTURE PROFILE AND THE DISRUPTIVE INSOLATION EFFECTS DURING THE DAYTIME. WILL CONTINUE TO HIGHLIGHT THIS EVENT IN THE HWO...BUT WILL HOLD OFF FOR ANOTHER MODEL RUN TO ASSESS THE POSSIBILITY OF A LAKE SNOW WATCH. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH MONDAY AND TUESDAY. THE COLD AIR ADVECTION WILL KEEP HIGHS LIMITED TO THE LOW AND MID 30S...AND ONLY UPPER 20S OVER THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER AND TUG HILL ON TUESDAY. OVERNIGHT LOWS WILL BE IN THE 20S MONDAY AND TUESDAY NIGHTS. WEDNESDAY WILL HAVE A SLIGHT RISE IN TEMPS WITH HIGHS IN THE 30S ACROSS THE REGION AND BACK TO 20S WEDNESDAY NIGHT. && .LONG TERM /THURSDAY THROUGH SATURDAY/... NOW HERE IS THE GOOD NEWS...WE BEGIN TO SEE TEMPERATURES MODERATING BACK TO NORMAL THROUGH NEXT WEEKEND. WE WILL SEE SOME BRIEF RIDGING ON THURSDAY BRINGING A SUNNY DAY WITH WARMER TEMPS RISING INTO THE UPPER 40S. SIMILAR CONDITIONS TO WHAT WE SAW THIS FINE SATURDAY AFTERNOON. THE FORECAST BECOMES A BIT DIFFICULT ON FRIDAY WHERE BOTH GFS AND EC MODELS PHASE THE TWO SHORTWAVES TOGETHER ALONG THE EAST COAST WITH DEEP SURFACE CYCLOGENESIS OCCURRING. THERE ARE SOME DIFFERENCES IN TIMING AND LOCATION OF THE FORMATION OF A STRONG SURFACE LOW BUT GENERALLY THE MODELS LIFT IT FROM THE CAROLINA COAST NORTH TOWARD NEW ENGLAND BY FRIDAY NIGHT. ANOTHER WEAKER SYSTEM WILL DRIFT ACROSS EASTERN CANADA. THERE IS POTENTIAL FOR EITHER SYSTEM TO CLIP OUR FORECAST AREA SO WILL GO WITH LOW CHANGE FOR SHOWERS AT THIS TIME. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO INCREASE OVERNIGHT AS MOISTURE ASSOCIATED WITH THE APPROACHING MIDWEST FRONT MOVES SLOWLY TO THE EAST. A FEW SHOWERS MAY DEVELOP LATE SUNDAY MORNING ACROSS THE FINGER LAKES AND CENTRAL NEW YORK...AND THEN SPREAD INTO THE EASTERN LAKE ONTARIO REGION BY EARLY AFTERNOON WITH LOCAL MVFR CONDITIONS. IT APPEARS THIS FIRST BATCH OF SHOWERS WILL REMAIN JUST EAST OF THE TAF SITES. LATER SUNDAY AFTERNOON PERIODS OF RAIN WILL BECOME MORE WIDESPREAD ACROSS THE REGION AND LAST THROUGH SUNDAY EVENING BEFORE TAPERING OFF FROM WEST TO EAST. THIS WILL PRODUCE AREAS OF MVFR...WITH IFR ACROSS THE HIGHER TERRAIN. OUTLOOK... MONDAY...VFR/MVFR WITH A FEW SNOW SHOWERS LIKELY. MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS...EXCEPT IFR IN LAKE EFFECT SNOW EAST OF THE LAKES. WEDNESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS. THURSDAY...VFR. && .MARINE... SOUTHERLY WINDS WILL INCREASE TODAY AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL SWEEP ACROSS THE LOWER LAKES TONIGHT. FOLLOWING THE FRONT MODERATE TO STRONG WESTERLIES WILL BRING AN EXTENDED PERIOD OF SMALL CRAFT CONDITIONS TO BOTH LAKES THROUGH MIDWEEK. WINDS MAY GET CLOSE TO GALE FORCE AT TIMES MONDAY AND TUESDAY ON LAKE ONTARIO. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM EDT MONDAY FOR LEZ040- 041. SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 AM EDT TUESDAY FOR LOZ042-043. SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR LOZ044-045. && $$ SYNOPSIS...TMA NEAR TERM...TMA SHORT TERM...WCH LONG TERM...SMITH/WCH AVIATION...TMA MARINE...TMA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
119 AM EDT SUN MAR 31 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE OHIO VALLEY TODAY...PROVIDING A CHANCE OF RAIN. A COLD FRONT WILL THEN MOVE THROUGH TONIGHT...PROVIDING COOLER TEMPERATURES FOR THE FIRST PART OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... PCPN IS BEGINNING TO FORM IN SOUTH CENTRAL KY IN RESPONSE TO THE H5 S/W THAT IS WORKING UP THE OHIO VALLEY. 18Z LOW DEVELOPED A MORE DEFINED SFC LOW AND MOVED IT ACROSS THE FA OVERNIGHT. THE 00Z NAM IS A LITTLE LESS DEVELOPED PUT STILL PUSHES THE BEST PCPN ACROSS THE SE QUARTER OF THE FA BETWEEN 06Z-12Z. THE PREVIOUS FORECAST HAD THIS SCENARIO...SO ONLY ADJUSTED THE TIMING A LITTLE AT THE BEGINNING. TEMPERATURES IN THE E COOLED OFF QUICKLY THIS EVENING WITH THE DRY DEWPOINTS AND MIGHT DROP A FEW MORE DEGREES BEFORE STARTING TO RISE TOWARDS MORNING. OVERALL KEPT THE LOWS IN THE PREVIOUS FORECAST RANGES. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/... A SHORTWAVE CURRENTLY MOVING THROUGH THE MIDDLE MISSISSIPPI VALLEY WILL BEGIN TO AFFECT THE WESTERN CWA BY 06Z. THE AMPLITUDE OF THIS SHORTWAVE IS NOT ESPECIALLY STRONG...AND IT IS SOMEWHAT TOUGH TO DISCERN WHEN LOOKING ONLY AT 500MB HEIGHT CONTOURS. WITH THE DRY AIR IN PLACE OVER MUCH OF THE OHIO VALLEY RIGHT NOW...IT IS NOT ENTIRELY SURPRISING THAT THE TREND HAS BEEN TOWARD SLIGHTLY DRIER SOLUTIONS FOR SUNDAY MORNING. THE SIGNAL FROM THE HIGH- RESOLUTION OUTPUT IS CONFLICTING...WITH THE 12Z SPC-WRF INDICATING ONLY SCATTERED SHOWERS (AND SOME BIG DRY PATCHES)...AND THE MOST RECENT HRRR RUN SHOWING A SOLID AREA OF PRECIPITATION FOR THE SOUTHERN HALF OF THE CWA. TIMING WAS ADJUSTED ON THE POPS...WITH A SLIGHTLY ADJUSTMENT DOWNWARD IN VALUE AS WELL...AND NO HIGHER THAN LIKELY FOR THE SOUTHERN CWA. AN ASPECT OF THE SYSTEM THAT IS AGREED UPON FROM ALL SOURCES IS A SPLIT IN THE PRECIPITATION BETWEEN A SOUTHERN AREA OF PRECIPITATION (PRIMARILY AFFECTING KENTUCKY AND TENNESSEE) AND WITH A NORTHERN STREAM SYSTEM MOVING THROUGH MICHIGAN. THE NORTHERN SYSTEM WILL LAG BEHIND THE SOUTHERN SYSTEM BY SEVERAL HOURS...BUT THIS WILL LIKELY ACT TO INITIATE MORE SHOWERS OVER THE EASTERN CWA THROUGH MID-AFTERNOON. SPC SREF PARAMETERS INDICATE THAT SOME WEAK INSTABILITY COULD BUILD IN TO THE SOUTHEASTERN AND EASTERN CWA DURING THIS TIME FRAME...SO THUNDER WAS KEPT IN THE FORECAST. BY SUNDAY NIGHT...A COLD FRONT WILL BE MOVING INTO THE NORTHERN PORTIONS OF THE CWA. WHILE THE COLD ADVECTION IS NOTABLE BEHIND THE FRONT...THE SURFACE PRESSURE PATTERN IS WEAK...AND FORCING IS ALMOST NON-EXISTENT. AS A RESULT OF THIS...THE FRONT SHOULD PASS THROUGH DRY. HOWEVER...IN A REGION OF COLD ADVECTION BEHIND THE FRONT...A WEAK RIPPLE IN THE FLOW (ROUNDING THE SOUTHWESTERN EDGE OF THE LARGE UPPER TROUGH) WILL PASS INTO THE CWA. THIS FEATURE MAY BRING A BAND OF LIGHT PRECIPITATION DURING THE FIRST TWO-THIRDS OF MONDAY. HOWEVER...THIS HAS BEEN MODELED DRIER ON THE LAST SET OF RUNS...SO POPS HAVE BEEN LIMITED TO 20 PERCENT. TEMPERATURES SUPPORT A MIX OF SNOW AND RAIN (WITH GENERALLY SNOW IN THE NORTH AND GENERALLY RAIN IN THE SOUTH)...BUT AS QPF IS EXTREMELY LIGHT...THE DAY SHOULD NOT BE A STRIKEOUT. WITH THE ONLY SIGNIFICANT TEMPERATURE ADVECTION OCCURRING SUNDAY NIGHT WITH THE COLD FRONT...TEMPS SHOULD REMAIN GENERALLY DIURNAL THROUGH THE PERIOD. AFTER A DAY OF COLD ADVECTION AND AS SKIES CLEAR OUT MONDAY NIGHT...TEMPS APPEAR TO BE SET TO DROP INTO THE 20S...10-15 DEGREES BELOW NORMAL FOR EARLY APRIL. && .LONG TERM /TUESDAY THROUGH SATURDAY/... DEEP MID LVL TROUGH WILL PROGRESS EASTWARD TUESDAY INTO WEDNESDAY ALLOWING SFC HIGH PRESSURE TO SETTLE INTO THE GREAT LAKES AND OHIO VALLEY. ON TUESDAY...THERE COULD BE SOME DIURNALLY DRIVEN CUMULUS BUT IT LOOKS LIKE MOST OF THE REGION WILL BE MOSTLY SUNNY. IT SHOULD BE MOSTLY CLEAR TUESDAY NIGHT AND MOSTLY SUNNY ON WEDNESDAY. COLDEST TEMPERATURES ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. HIGHS ON TUESDAY WILL RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH. LOWS TUESDAY NIGHT WILL DROP INTO THE LOWER AND MID 20S. SOME MODIFICATION IS EXPECTED ON WEDNESDAY BUT TEMPERATURES WILL REMAIN BELOW NORMAL FOR EARLY APRIL. HIGHS WILL RANGE FROM THE LOWER 40S NE TO THE UPPER 40S SOUTHWEST. UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN LATE IN THE WEEK. THERE WILL BE A SPLIT FLOW BETWEEN NRN STREAM ENERGY AND SRN STREAM ENERGY. MODELS HAVE BEEN OSCILLATING ON HOW THE NRN STREAM ENERGY WILL INTERACT WITH THE SRN STREAM ENERGY. FOR NOW...HAVE KEPT AN UPR LVL LOW AND PCPN WITH THE SRN STREAM ENERGY TO OUR SOUTH AND EAST THURSDAY INTO FRIDAY WHILE A WEAK COLD FRONT DROPS SOUTHEAST THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL CONTINUE TO MODERATE WITH HIGHS IN THE 50S ON THURSDAY AND 50S TO NEAR 60 ON FRIDAY. FOR FRIDAY NIGHT INTO SATURDAY...SURFACE HIGH PRESSURE WILL PUSH INTO THE REGION AND WILL EVENTUALLY MOVE EAST. DRY WEATHER WITH TEMPERATURES NEAR SEASONAL NORMALS ARE EXPECTED. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS WILL START OUT THE TAF PERIOD. A DISTURBANCE WILL WORK INTO THE TAF SITES OVERNIGHT AND INTO THE DAYTIME MORNING HOURS. THIS DISTURBANCE WILL BRING RAIN SHOWERS TO THE AREA. VSBYS MAY BE REDUCED TO MVFR WITH THE SHOWER ACTIVITY. MVFR CIGS WILL DEVELOP AND MOVE INTO THE REGION DURING THE MORNING HOURS AND REMAIN ACROSS THE TAF SITES THROUGH AROUND MID DAY. EXPECT VFR CONDITIONS TO RETURN TO THE TAF SITES AROUND MID DAY AND BY THEN MOST OF THE SHOWER ACTIVITY WILL BE OUT OF THE TAF SITES. SOME RESIDUAL SHOWER ACTIVITY MAY LINGER AT KCMH AND KLCK INTO THE MID AFTERNOON HOURS. WINDS WILL PICK UP FOR THE DAYTIME HOURS WITH WINDS GUSTING AROUND 20 TO 25 KNOTS DURING THE AFTERNOON AND EARLY EVENING HOURS. WIND GUSTS WILL SUBSIDE SUNDAY EVENING HOWEVER EXPECT WINDS TO STAY UP SOME THROUGH THE NIGHT TONIGHT. ANOTHER DISTURBANCE WILL MOVE THROUGH TONIGHT AND WILL BRING SOME LIGHT PRECIPITATION TO THE TAF SITES FOR A COUPLE OF HOURS. OUTLOOK...MVFR CONDITIONS POSSIBLE ON MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...SITES SHORT TERM...HATZOS LONG TERM...HICKMAN AVIATION...NOVAK
AREA FORECAST DISCUSSION...CORRECTED
NWS MEDFORD OR
1020 PM PDT SAT MAR 30 2013 .DISCUSSION...AN UPDATE HAS BEEN ISSUED TO LOWER THE SUNDAY MORNING POPS IN SOUTHERN OREGON. THERE STILL MAY BE A FEW SHOWERS NORTH OF THE BORDER..BUT BEFORE 11 AM ON SUNDAY THE RAP AND GFS MODELS BOTH SHOW THE LARGE MAJORITY OF THE SHOWERS REMAINING IN NORTHERN CALIFORNIA. BY THE AFTERNOON...THE DEFORMATION BAND WILL SHIFT NORTHWARD WITH THE HIGHEST QPF LIKELY OCCURRING NEAR THE OREGON/CALIFORNIA BORDER. THE BROAD CLOSED UPPER LOW OFFSHORE FROM SAN FRANCISCO ALONG 130W IS MOVING EAST-NORTHEAST AND WILL MOVE INLAND BY SUNDAY EVENING. A SHORTWAVE ROTATING AROUND THE LOW HELPED THUNDERSTORMS TO DEVELOP OVER THE NORTHERN SIERRA NEVADA THIS AFTERNOON THEN BY EARLY EVENING THEY SPREAD INTO EASTERN SISKIYOU COUNTY BEFORE CONTINUING NORTHWESTWARD ACROSS YREKA AND SEIAD VALLEY. AFTER 630 PM...A MULTI-CELLULAR THUNDERSTORM STRENGTHENED OVER THE APPLEGATE VALLEY AND MOVED ACROSS THE GRANTS PASS...MERLIN AND WILDERVILLE AREA. BESIDES LIGHTNING...THE MAIN DISTINGUISHING CHARACTERISTIC WAS GUSTY DOWNDRAFT WINDS. THIS INCLUDED A GUST TO 38 MPH MEASURED AT THE MEDFORD AIRPORT AND ESTIMATED GUSTS OF 40 TO 50 MPH ACROSS CENTRAL JOSEPHINE COUNTY. THE THUNDERSTORMS WERE AT THEIR STRONGEST BETWEEN 7 PM AND 8 PM AND THE STRONGEST OF THE CELLS IS FINALLY WEAKENING NOW NEAR AGNESS AND GOLD BEACH IN CURRY COUNTY. MOVING FORWARD...THE SOUTHEAST WINDS ALOFT WILL BACK TO THE EAST TONIGHT WITH A SLIGHT CHANCE OF ADDITIONAL THUNDERSTORMS BUT MAINLY SIMPLY SCATTERED LIGHT TO MODERATE SHOWERS. FOR EASTER SUNDAY...ANOTHER COUPLE OF STRONGER SHORTWAVES THAT ARE PRESENTLY REACHING SOUTHERN CALIFORNIA WILL BRING AN INCREASE IN COVERAGE AND INTENSITY OF SHOWERS. THE ACTIVITY OVERNIGHT INTO SUNDAY MORNING WILL BE FOCUSED FROM THE SIERRA NEVADA INTO SISKIYOU COUNTY BUT BY MID TO LATE MORNING THEN THROUGH SUNDAY NIGHT RAIN SHOWERS ARE LIKELY ACROSS OUR AREA AND THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS. THE SHOWERY NATURE OF THE PRECIPITATION WILL LIKELY LEAD TO A WIDE RANGE OF QPF AMOUNTS BUT AMOUNTS OF A QUARTER TO A HALF OF AN INCH SHOULD BE COMMON. THE UPPER LOW IS FORECAST TO EXIT EAST INTO NEVADA ON MONDAY BUT WRAP-AROUND SHOWERS ARE LIKELY...ESPECIALLY IN THE MORNING AND EAST OF THE CASCADES. HIGH PRESSURE WILL BRING A RETURN OF WARM AND DRY WEATHER TUESDAY THROUGH WEDNESDAY THEN A SERIES OF FRONTAL SYSTEMS WILL LIKELY BRING WET AND COOLER WEATHER FOR THE REMAINDER OF THE WEEK. && .AVIATION... BASED ON THE 31/00Z TAF CYCLE. IFR CONDITIONS WILL DEVELOP OVERNIGHT ALONG THE COAST AS ONSHORE FLOW CONTINUES. SHOWERS AND ISOLATED THUNDERSTORMS ARE LIKELY TO REMAIN MOSTLY FROM THE SISKIYOUS AND THE CURRY AND JOSEPHINE COUNTY COASTAL MOUNTAINS SOUTHWARD OVERNIGHT. MVFR CONDITIONS WILL DEVELOP ACROSS THE WEST SIDE DURING THE DAY ON EASTER SUNDAY. THERE WILL BE A THREAT OF THUNDERSTORMS AS WELL AS SHOWERS THAT WILL BE MODERATE TO LOCALLY HEAVY AT TIMES FROM ABOUT THE MEDFORD AREA SOUTHWARD AND EASTWARD DURING THE AFTERNOON AND EVENING. BTL && .PREV DISCUSSION... /ISSUED 256 PM PDT SAT MAR 30 2013/ SHORT TERM...A CUTOFF LOW OFF THE CENTRAL CALIFORNIA COAST REMAINS THE MAIN WEATHER MAKER FOR THE NEXT COUPLE DAYS. THIS LOW IS MOVING TOWARDS THE REGION TODAY AND IS FORECAST TO MOVE INLAND SUNDAY AND MONDAY. THEN A HIGH PRESSURE RIDGE WILL BRING WARM AND DRY CONDITIONS BEGINNING TUESDAY. AHEAD OF THIS LOW...MOISTURE AND INSTABILITY ARE INCREASING TODAY. ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON TO THE SOUTH IN LASSEN AND SHASTA COUNTY WHERE THE BEST LIFT IS INDICATED IN THE MESO ANALYSIS AND RAP FORECAST. ALSO, MESO ANALYSIS SHOWS PRECIPITABLE WATER VALUES OF 0.8 INCHES ALONG THE NORTHERN CALIFORNIA COAST. INLAND PW AMOUNTS RANGE FROM 0.4 TO 0.7 INCHES AND WILL INCREASE LATE THIS AFTERNOON AND THIS EVENING AS MOISTURE MOVES UP FROM THE SOUTH AND SOUTHEAST INTO THE AREA. DAYTIME HEATING WILL RESULT IN SURFACE BASED INSTABILITY AND MODELS SHOW INCREASING LIFT OVER CENTRAL PORTIONS AND SOUTHERN PORTIONS OF THE AREA IN THE LATE AFTERNOON AND EVENING. ALSO MODELS SHOW THAT CAPE WILL INCREASE FROM THE CASCADES WEST DURING THIS PERIOD. THE INCREASE IN MOISTURE...LIFT AND INSTABILITY WILL ALLOW SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON INTO THIS EVENING OVER SISKIYOU AND MODOC COUNTIES IN NORTHERN CALIFORNIA AND OVER SOUTHWESTERN PORTIONS OF SOUTHERN OREGON....MAINLY FROM KLAMATH COUNTY WEST. ADDITIONALLY A BAND OF SHOWERS IS EXPECTED TO MOVE INTO THE CWA FROM THE SOUTH LATE THIS EVENING AND TONIGHT. SOME ISOLATED EMBEDDED THUNDERSTORMS AS WELL AS AREAS OF MODERATE TO HEAVY RAIN ARE ALSO POSSIBLE WITH THIS LINE. ON SUNDAY...THE LOW BEGINS TO MOVES INLAND TO THE SOUTH AND WILL BRING CONTINUED MOISTURE AND SHOWERS TO THE AREA. BY AFTERNOON...EXPECT SHOWERS TO BECOME WIDESPREAD OVER MOST THE AREA. INSTABILITY INCREASES OVER THE AREA AGAIN SUNDAY AFTERNOON. HAVE EXPANDED THE SLIGHT RISK OF THUNDERSTORMS OVER THE INLAND AREAS SUNDAY AFTERNOON INTO SUNDAY EVENING GIVEN THE MODEL CONSENSUS ON BETTER INSTABILITY...AS WELL AS INCREASED DIVERGENCE ALOFT AND CONTINUED MOISTURE CONVERGENCE OVER PORTIONS OF THE CWA. ON MONDAY...MODELS CONTINUE TO SHOW DIFFERENCES ON THE SPEED OF THE LOW AS IT MOVES EAST INTO NEVADA AND UTAH WITH THE ECMWF BEING SLOWER THAN THE GFS AND NAM. HAVE COMPROMISED IN THE FORECAST WITH CHANCE POPS OVER THE CENTRAL AND EASTERN PORTIONS OF THE CWA AND A SLIGHT CHANCE ELSEWHERE. BY MONDAY NIGHT EXPECT SHOWER ACTIVITY TO DIMINISH ACROSS THE AREA AS A STRONG RIDGE OF HIGH PRESSURE BUILDS INTO PLACE. ON TUESDAY...A RIDGE WILL BRING DRY AND VERY WARM CONDITIONS WITH HIGHS IN THE UPPER 60S TO MID 70S FOR VALLEYS WEST OF THE CASCADES AND IN THE MID 60S EAST OF THE CASCADES. THESE WARM AND DRY CONDITIONS CONTINUE INTO WEDNESDAY. LONG TERM...AN ACTIVE PATTERN IS IN THE WORKS STARTING NEXT THURSDAY AND COULD LAST THROUGH NEXT WEEKEND. THE EC AND GFS OPERATIONAL AND ENSEMBLE MEANS HAVE BEEN TRENDING IN THIS DIRECTION FOR THE PAST FEW DAYS. SO CONFIDENCE IS BECOMING HIGHER WE`LL BE HEADING INTO A COOLER AND WETTER PATTERN....BUT LESS CONFIDENT ON THE TIMING OF EACH INDIVIDUAL SYSTEM. THE EC IS SLOWER THEN THE GFS WITH A NEGATIVE TILTED TROUGH MOVING INTO THE AREA THURSDAY AFTERNOON. SO WE`LL CONTINUE TO GO ABOVE CLIMO FROM THURSDAY ONWARD IN THE EXTENDED. TEMPERATURES ARE ALSO LIKELY TO BE BELOW NORMAL DURING THE DAY...BUT NEAR OR SLIGHTLY ABOVE NORMAL AT NIGHT DUE TO CLOUD COVER AND PRECIPITATION. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PACIFIC COASTAL WATERS...NONE. $$ DW/BTL/NSK
AREA FORECAST DISCUSSION
NWS MEDFORD OR
913 PM PDT SAT MAR 30 2013 .DISCUSSION...THE BROAD CLOSED UPPER LOW OFFSHORE FROM SAN FRANCISCO ALONG 130W IS MOVING EAST-NORTHEAST AND WILL MOVE INLAND BY SUNDAY EVENING. A SHORTWAVE ROTATING AROUND THE LOW HELPED THUNDERSTORMS TO DEVELOP OVER THE NORTHERN SIERRA NEVADA THIS AFTERNOON THEN BY EARLY EVENING THEY SPREAD INTO EASTERN SISKIYOU COUNTY BEFORE CONTINUING NORTHWESTWARD ACROSS YREKA AND SEIAD VALLEY. AFTER 630 PM...A MULTI-CELLULAR THUNDERSTORM STRENGTHENED OVER THE APPLEGATE VALLEY AND MOVED ACROSS THE GRANTS PASS...MERLIN AND WILDERVILLE AREA. BESIDES LIGHTNING...THE MAIN DISTINGUISHING CHARACTERISTIC WAS GUSTY DOWNDRAFT WINDS. THIS INCLUDED A GUST TO 38 MPH MEASURED AT THE MEDFORD AIRPORT AND ESTIMATED GUSTS OF 40 TO 50 MPH ACROSS CENTRAL JOSEPHINE COUNTY. THE THUNDERSTORMS WERE AT THEIR STRONGEST BETWEEN 7 PM AND 8 PM AND THE STRONGEST OF THE CELLS IS FINALLY WEAKENING NOW NEAR AGNESS AND GOLD BEACH IN CURRY COUNTY. MOVING FORWARD...THE SOUTHEAST WINDS ALOFT WILL BACK TO THE EAST TONIGHT WITH A SLIGHT CHANCE OF ADDITIONAL THUNDERSTORMS BUT MAINLY SIMPLY SCATTERED LIGHT TO MODERATE SHOWERS. FOR EASTER SUNDAY...ANOTHER COUPLE OF STRONGER SHORTWAVES THAT ARE PRESENTLY REACHING SOUTHERN CALIFORNIA WILL BRING AN INCREASE IN COVERAGE AND INTENSITY OF SHOWERS. THE ACTIVITY OVERNIGHT INTO SUNDAY MORNING WILL BE FOCUSED FROM THE SIERRA NEVADA INTO SISKIYOU COUNTY BUT BY MID TO LATE MORNING THEN THROUGH SUNDAY NIGHT RAIN SHOWERS ARE LIKELY ACROSS OUR AREA AND THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS. THE SHOWERY NATURE OF THE PRECIPITATION WILL LIKELY LEAD TO A WIDE RANGE OF QPF AMOUNTS BUT AMOUNTS OF A QUARTER TO A HALF OF AN INCH SHOULD BE COMMON. THE UPPER LOW IS FORECAST TO EXIT EAST INTO NEVADA ON MONDAY BUT WRAP-AROUND SHOWERS ARE LIKELY...ESPECIALLY IN THE MORNING AND EAST OF THE CASCADES. HIGH PRESSURE WILL BRING A RETURN OF WARM AND DRY WEATHER TUESDAY THROUGH WEDNESDAY THEN A SERIES OF FRONTAL SYSTEMS WILL LIKELY BRING WET AND COOLER WEATHER FOR THE REMAINDER OF THE WEEK. && .AVIATION... BASED ON THE 31/00Z TAF CYCLE. IFR CONDITIONS WILL DEVELOP OVERNIGHT ALONG THE COAST AS ONSHORE FLOW CONTINUES. SHOWERS AND ISOLATED THUNDERSTORMS ARE LIKELY TO REMAIN MOSTLY FROM THE SISKIYOUS AND THE CURRY AND JOSEPHINE COUNTY COASTAL MOUNTAINS SOUTHWARD OVERNIGHT. MVFR CONDITIONS WILL DEVELOP ACROSS THE WEST SIDE DURING THE DAY ON EASTER SUNDAY. THERE WILL BE A THREAT OF THUNDERSTORMS AS WELL AS SHOWERS THAT WILL BE MODERATE TO LOCALLY HEAVY AT TIMES FROM ABOUT THE MEDFORD AREA SOUTHWARD AND EASTWARD DURING THE AFTERNOON AND EVENING. BTL && .PREV DISCUSSION... /ISSUED 256 PM PDT SAT MAR 30 2013/ SHORT TERM...A CUTOFF LOW OFF THE CENTRAL CALIFORNIA COAST REMAINS THE MAIN WEATHER MAKER FOR THE NEXT COUPLE DAYS. THIS LOW IS MOVING TOWARDS THE REGION TODAY AND IS FORECAST TO MOVE INLAND SUNDAY AND MONDAY. THEN A HIGH PRESSURE RIDGE WILL BRING WARM AND DRY CONDITIONS BEGINNING TUESDAY. AHEAD OF THIS LOW...MOISTURE AND INSTABILITY ARE INCREASING TODAY. ISOLATED THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON TO THE SOUTH IN LASSEN AND SHASTA COUNTY WHERE THE BEST LIFT IS INDICATED IN THE MESO ANALYSIS AND RAP FORECAST. ALSO, MESO ANALYSIS SHOWS PRECIPITABLE WATER VALUES OF 0.8 INCHES ALONG THE NORTHERN CALIFORNIA COAST. INLAND PW AMOUNTS RANGE FROM 0.4 TO 0.7 INCHES AND WILL INCREASE LATE THIS AFTERNOON AND THIS EVENING AS MOISTURE MOVES UP FROM THE SOUTH AND SOUTHEAST INTO THE AREA. DAYTIME HEATING WILL RESULT IN SURFACE BASED INSTABILITY AND MODELS SHOW INCREASING LIFT OVER CENTRAL PORTIONS AND SOUTHERN PORTIONS OF THE AREA IN THE LATE AFTERNOON AND EVENING. ALSO MODELS SHOW THAT CAPE WILL INCREASE FROM THE CASCADES WEST DURING THIS PERIOD. THE INCREASE IN MOISTURE...LIFT AND INSTABILITY WILL ALLOW SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON INTO THIS EVENING OVER SISKIYOU AND MODOC COUNTIES IN NORTHERN CALIFORNIA AND OVER SOUTHWESTERN PORTIONS OF SOUTHERN OREGON....MAINLY FROM KLAMATH COUNTY WEST. ADDITIONALLY A BAND OF SHOWERS IS EXPECTED TO MOVE INTO THE CWA FROM THE SOUTH LATE THIS EVENING AND TONIGHT. SOME ISOLATED EMBEDDED THUNDERSTORMS AS WELL AS AREAS OF MODERATE TO HEAVY RAIN ARE ALSO POSSIBLE WITH THIS LINE. ON SUNDAY...THE LOW BEGINS TO MOVES INLAND TO THE SOUTH AND WILL BRING CONTINUED MOISTURE AND SHOWERS TO THE AREA. BY AFTERNOON...EXPECT SHOWERS TO BECOME WIDESPREAD OVER MOST THE AREA. INSTABILITY INCREASES OVER THE AREA AGAIN SUNDAY AFTERNOON. HAVE EXPANDED THE SLIGHT RISK OF THUNDERSTORMS OVER THE INLAND AREAS SUNDAY AFTERNOON INTO SUNDAY EVENING GIVEN THE MODEL CONSENSUS ON BETTER INSTABILITY...AS WELL AS INCREASED DIVERGENCE ALOFT AND CONTINUED MOISTURE CONVERGENCE OVER PORTIONS OF THE CWA. ON MONDAY...MODELS CONTINUE TO SHOW DIFFERENCES ON THE SPEED OF THE LOW AS IT MOVES EAST INTO NEVADA AND UTAH WITH THE ECMWF BEING SLOWER THAN THE GFS AND NAM. HAVE COMPROMISED IN THE FORECAST WITH CHANCE POPS OVER THE CENTRAL AND EASTERN PORTIONS OF THE CWA AND A SLIGHT CHANCE ELSEWHERE. BY MONDAY NIGHT EXPECT SHOWER ACTIVITY TO DIMINISH ACROSS THE AREA AS A STRONG RIDGE OF HIGH PRESSURE BUILDS INTO PLACE. ON TUESDAY...A RIDGE WILL BRING DRY AND VERY WARM CONDITIONS WITH HIGHS IN THE UPPER 60S TO MID 70S FOR VALLEYS WEST OF THE CASCADES AND IN THE MID 60S EAST OF THE CASCADES. THESE WARM AND DRY CONDITIONS CONTINUE INTO WEDNESDAY. LONG TERM...AN ACTIVE PATTERN IS IN THE WORKS STARTING NEXT THURSDAY AND COULD LAST THROUGH NEXT WEEKEND. THE EC AND GFS OPERATIONAL AND ENSEMBLE MEANS HAVE BEEN TRENDING IN THIS DIRECTION FOR THE PAST FEW DAYS. SO CONFIDENCE IS BECOMING HIGHER WE`LL BE HEADING INTO A COOLER AND WETTER PATTERN....BUT LESS CONFIDENT ON THE TIMING OF EACH INDIVIDUAL SYSTEM. THE EC IS SLOWER THEN THE GFS WITH A NEGATIVE TILTED TROUGH MOVING INTO THE AREA THURSDAY AFTERNOON. SO WE`LL CONTINUE TO GO ABOVE CLIMO FROM THURSDAY ONWARD IN THE EXTENDED. TEMPERATURES ARE ALSO LIKELY TO BE BELOW NORMAL DURING THE DAY...BUT NEAR OR SLIGHTLY ABOVE NORMAL AT NIGHT DUE TO CLOUD COVER AND PRECIPITATION. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PACIFIC COASTAL WATERS...NONE. $$ DW/BTL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
434 AM EDT SUN MAR 31 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION FROM THE WEST TONIGHT...WITH A SECOND COLD FRONT MOVING OVER THE AREA MONDAY NIGHT. HIGH PRESSURE WILL FILL IN BEHIND THE SECOND FRONT USHERING IN COOLER THAN NORMAL TEMPERATURES THROUGH THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... 430 AM EDT UPDATE...NO SIGFNT CHANGES NEED TO THE FCST. TEMPS AND TD/S ARE PRETTY MUCH LOCKED IN WITH THE SATURATED SFC LAYER CWFA/WIDE. POPS ARE STILL LOOKING GOOD WITH RADAR TRENDS AND HI/RES MODEL OUTPUT. IN FACT...THE LATEST HRRR AGREES WELL WITH THE 00Z WRF MODELS WITH THE MOVEMENT AND MASS FIELDS ASSOCIATED WITH THE WARM FRONT. THIS GIVES GOOD CONFIDENCE IN THE EXPECTED GENERAL WANING OF PRECIP...WHICH THE MAJORITY SHOULD BE PUSHING EAST OF THE FCST AREA BY 13Z/14Z. PRECIP AMOUNTS PER THE RAIN GAUGE NETWORK AND COMP RADAR IS RIGHT ON TRACK WITH THE FCST/D AMOUNTS AND PLACEMENT. AS OF 305 AM EDT SUNDAY...A WARM FRONT IS BISECTING THE CWFA ATTM WITH A WIDESPREAD PRECIP SHIELD REACHING NEARLY ALL ZONES EXCEPT THE FAR NW/RN COUNTIES. HYDROVIEW IS SHOWING 8-HR PRECIP AMOUNTS RANGING FROM A HALF AN INCH ACROSS NE GA TO LESS THAN A TENTH EAST OF I-26. BASED ON EXPECTED RADAR TRENDS...THIS FITS WELL WITH THE OVERALL FCST/D AMOUNTS THROUGH 12Z. EXPECT ANOTHER HALF INCH OR SO ACROSS THE ERN HALF OF THE CWFA AND PERHAPS A COUPLE MORE TENTHS WEST BY THE TIME THE FRONT PUSHES NE OF THE AREA AROUND 14Z. NO HYDRO CONCERNS ARE HAD WITH THIS BENEFICIAL RAINFALL. THE AREA WILL REMAIN IN SMALL WARM SECTOR TODAY AND A FAIRLY TIGHT P/GRAD WILL DEVELOP ASSOCIATED WITH THE OVERALL COMPACT SYSTEM. THIS WILL ENABLE SUSTAINED WINDS OF 12+ KTS THIS AFTERNOON...YET WITH LOW END GUSTS DUE TO THE WAA PATTERN AND RISING MOTION. THE SW SFC FLOW WILL ALLOW TD/S TO MODIFY INTO THE L50S ACROSS THE SW/RN ZONES AND THIS WILL PROBABLY BE ENOUGH FOR ISOL THUNDER LATE THIS AFTERNOON... ENDING QUICKLY AFT 00Z. SOUNDINGS SHOW UNIDIRECTIONAL AND RELATIVELY WEAK SHEAR ALONG WITH SHALLOW AND LOW SBCAPE...WHILE UPPER DIV IS AND SYNOPTIC FORCING IS DISPLACED NORTH OF THE BEST THERMODYNAMICAL REGION. SO...WILL ANTICIPATE GENERAL TS WITH CTG LIGHTNING AS THE MAIN THREAT. THE COLD FRONT ADVANCES UPON THE CWFA TONIGHT AND INCREASES THE DEEP LAYERED LIFT. HOWEVER...WITH A NOCTURNAL FROPA...DON/T ANTICIPATE MUCH MORE THAN -SHRA WITH RELATIVELY LOW QPF. THE FRONT ITSELF IS DISJOINTED FROM IT/S PARENT OCCLUDED SFC LOW BY 06Z AND WILL HAVE NEGLIGIBLE UPPER SUPPORT. THUS...THE BEST LIFT WILL BE MECH ACROSS THE MTNS AND TO THE SW OF THE CWFA ASSOCIATED WITH A LLVL THETA/E RIDGE. THE FAR SRN ZONES COULD SEE A NEW 12-HR RAINFALL OF 0.25 INCHES WITH QUICKLY DIMINISHING AMOUNTS TO THE NORTH THROUGH 12Z. MAX TEMPS WILL BE SEASONAL...PERHAPS A COUPLE DEGREES ABOVE WITH SOME BRIEF SCATTERING AND DECENT WAA. MINS WILL REMAIN ABOUT 6-8 DEGREES ABOVE NORMAL WITH PLENTY OF CLOUD COVER/PRECIP AND A NW/LY WIND SHIFT NOT OCCURRING UNTIL AROUND 10Z. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 245 AM SUNDAY...THE SHORT RANGE CONTINUES TO BE VEXED BY UNCERTAINTY WITH THE MODEL GUIDANCE...MOSTLY WITH HOW TO HANDLE THE LOCATION AND ACTIVITY ALONG TWO SURFACE COLD FRONTS. STARTING MONDAY MORNING...THE FIRST FRONT SHOULD BE LAID DOWN ACROSS THE COASTAL PLAIN...BUT THE BACK EDGE OF LIGHT PRECIP MIGHT STILL LINGER ACROSS THE SOUTHEASTERN ZONES. THAT FRONT SHOULD GET SOME ADDITIONAL EASTWARD PUSH IN THE MORNING...SO THINK ANY REMNANT PRECIP SHOULD LEAVE THE EASTERN ZONES EARLY IN THE DAY. MEANWHILE...THE NEXT FRONT WILL BE APPROACHING FROM THE NW...WITH SOME UPSLOPE FLOW OF MOISTURE AT LOW LEVELS INTO THE NC MTNS. BOTH MODELS SHOW SOME UPSLOPE PRECIP THROUGH THE AFTERNOON HOURS SO A CHANCE POP WAS KEPT ON THE TN BORDER THROUGH MIDDAY...BUT THEN DIMINISHES BY EVENING AS MOISTURE WILL BE LESS THAN IMPRESSIVE. IN BETWEEN...DO NOT EXPECT MUCH TO HAPPEN ACROSS THE MAJORITY OF THE FCST AREA...BECAUSE OF A LACK OF FORCING AND MOISTURE. INSTEAD...WE SHOULD EXPECT ANOTHER SEASONALLY WARM DAY WITH A WNW FLOW PROVIDING SOME DOWNSLOPE E OF THE MTNS THAT WILL HELP GET TEMPS A CATEGORY OR SO ABOVE NORMAL. FROM MONDAY EVENING ONWARD...CONFIDENCE SUFFERS A BIT. THE NAM MAINTAINS NW FLOW PRECIP ON THE TN BORDER THROUGH MONDAY NIGHT AND INTO TUESDAY MORNING WITH TEMPS COOL ENOUGH FOR MORE SNOW. THE GFS REMAINS DRY. NO CHANGES WILL BE MADE TO THE DRY FCST THAT WAS INHERITED. IN FACT...THE FCST WAS KEPT GFS-LIKE AND DRY THROUGH THE REST OF THE SHORT RANGE. THE SECOND FRONT SHOULD DROP DOWN ACROSS THE FCST AREA EARLY TUESDAY WHICH SHOULD DROP TEMPS BACK TWO CATEGORIES BELOW NORMAL. NOT READY TO BUY THE NAM SOLUTION OF MOVING AN AREA OF PRECIP ALONG THIS FRONT TUESDAY...AGAIN WITH POTENTIAL PRECIP TYPE ISSUES OVER THE MTNS. THE GFS EVENTUALLY BRINGS SOME LIGHT PRECIP AMTS ACROSS THE REGION FROM THE WEST TUESDAY NIGHT. CAN ENVISION SOMETHING FALLING OUT OF A MID LEVEL CLOUD DECK BUT IT PROBABLY WOULD NOT AMT TO MUCH. SIMILAR TO MONDAY NIGHT...HAVE KEPT AN ALREADY DRY FCST THE SAME WAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 315 AM SUNDAY...STARTING TO SEE SOME BETTER AGREEMENT AND RUN TO RUN CONSISTENCY OUT OF THE MEDIUM RANGE GUIDANCE WITH RESPECT TO THE NEXT SYSTEM EXPECTED DURING THE LATTER HALF OF THE WEEK. THE 00Z RUNS OF THE GFS AND ECMWF ACTIVATE THE OLD FRONTAL BOUNDARY TO OUR SOUTH ON WEDNESDAY NIGHT WITH MOISTURE RETURNING FROM THE GULF OVER THE TOP OF A COOL AND DRY LOW LEVEL AIR MASS WITH HIGH PRESSURE MOVING OVER THE MID-ATLANTIC REGION. ISENTROPIC LIFT GETS GOING BEFORE SUNRISE ON THURSDAY AND REMAINS PRODUCTIVE INTO THURSDAY NIGHT WITH PLENTY OF ATLANTIC AND GULF MOISTURE. WILL FOLLOW THE LEAD OF THE NEWER HPC GUIDANCE AND GET A JUMP ON RAISING PRECIP CHANCES INTO THE LIKELY RANGE FOR THURSDAY AND THURSDAY NIGHT...WITH A CHANCE LINGERING INTO FRIDAY. AM SKEPTICAL ABOUT THE EXTENT OF ANY WINTRY PRECIP EARLY THURSDAY AS GFS FCST SOUNDINGS ARE NOT REALLY SUPPORTIVE OF ANYTHING BUT RAIN. WILL ALSO HAVE TO CONSIDER LOWERING MAX TEMPS ON FRIDAY IF PRECIP LINGERS LONG ENOUGH. THE REST OF THE MEDIUM RANGE WAS LEFT ALONE FOR NOW. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... AT KCLT AND ELSEWHERE...PRECIP SHIELD IS MAKING IT/S WAY NE ACROSS THE CWFA AHEAD OF A WARM FRONT. SOME EMBEDDED HEAVIER SHOWERS HAVE PRODUCED VSBY/S IN THE IFR RANGE...BUT MOST OF THE PRECIP HAS BEEN LIGHTER. MOS GUIDANCE AND MODEL SOUNDINGS AGREE WITH THE DEVELOPMENT OF IFR CIGS THIS MORNING AT ALL SITES EXCEPT KAND WHERE CIGS WERE HELD AT MVFR. THE SFC P/GRAD TIGHTENS AFT SUNRISE AND LOW END GUSTS SHOULD DEVELOP OUTSIDE THE MTNS AND FOOTHILLS THROUGH THE AFTERNOON WITH THE AREA REMAINING IN A SLIGHT WAA PATTERN. THE ATMOS WILL LIKELY BECOME RELATIVELY UNSTABLE ACROSS THE SRN MOST ZONES THIS AFTERNOON...AND A PROB30 TS IS IN PLACE AFT 17Z FOR A FEW HRS AT KAND AND KCLT. OUTLOOK...FAIR WEATHER EXPECTED ON MON. ANOTHER COLD FRONT MOVES THROUGH ON TUESDAY...BUT RESTRICTIONS LOOK DOUBTFUL WITH THIS SYSTEM. DRY HIGH PRESSURE SETTLE OVER THE AREA ON WEDNESDAY. CONFIDENCE TABLE... 08-14Z 14-20Z 20-02Z 02-08Z KCLT MED 71% HIGH 81% HIGH 100% HIGH 100% KGSP HIGH 81% HIGH 94% HIGH 100% HIGH 95% KAVL MED 73% HIGH 87% HIGH 100% HIGH 100% KHKY MED 73% HIGH 82% HIGH 100% HIGH 100% KGMU MED 76% HIGH 93% HIGH 100% HIGH 100% KAND HIGH 94% HIGH 91% HIGH 100% HIGH 98% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...SBK NEAR TERM...SBK SHORT TERM...PM LONG TERM...PM AVIATION...SBK
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1149 PM CDT SAT MAR 30 2013 .AVIATION... NO MAJOR CHANGES FROM THE EARLIER TAF FORECAST. CHALLENGES ON TIMING MVFR CIGS...THUNDERSTORMS...AND THE COLD FRONT REMAIN. OUTSIDE OF AN ISOLATED SEVERE STORM IN SOUTHERN OKLAHOMA MOVING TOWARD THE ARKLATEX LATE THIS EVENING...LARGE SCALE ASCENT FROM A SHORTWAVE LIFTING OUT OF THE ROCKIES CAN NOW BE SEEN ON REGIONAL RADAR AROUND THE OK/TX PANHANDLES. VFR CONDITIONS WILL CONTINUE THROUGH 10Z AT DFW AIRPORTS AND 08Z AT WACO...BEFORE MVFR CIGS SEEN DEVELOPING ALONG THE COASTAL BEND ARRIVE INTO THE AIRPORTS. MODELS HAVE SLOWED THE COLD FRONT AND ARRIVAL OF A THUNDERSTORM COMPLEX UNTIL CLOSER TO MID MORNING SUNDAY FOR THE METRO AIRPORTS.... THEN TOWARD MIDDAY OR EARLY AFTERNOON AT WACO. WILL HOLD ON TO 3 HOUR TEMPO GROUP OF IFR CONDITIONS WITH THE HEAVIER RAINFALL WITH THE ACTIVITY. WINDS WILL START OFF ESE 5-10 KTS...THEN BECOME SE AROUND 10 KTS BEFORE SUNRISE AS STORM-RELATIVE INFLOW INCREASES AHEAD OF THE STORM COMPLEX MOVING SOUTHEAST THROUGH OKLAHOMA. WINDS BEHIND THE COLD FRONT WILL SHIFT TO THE NORTH 10-15 KTS...BEFORE VEERING NORTHEAST 5-10 KTS EVENING. 05/ && .UPDATE... IT IS QUIET ACROSS THE REGION AT THIS TIME BUT ANOTHER COMPLEX OF STORMS IS EXPECTED TO CROSS OUT OF OKLAHOMA AND INTO NORTH TEXAS NEAR DAYBREAK SUNDAY MORNING. BOTH THE LATEST NAM AND OCCASIONAL RUNS OF THE RAP DEVELOP STORMS AROUND AND/OR NORTHEAST OF THE DFW METROPLEX AROUND 4 AM. THE LATEST RUN OF THE RAP DOES NOT HAVE THESE STORMS. AROUND 4 AM...THE MODELS STILL HAVE THE BEST LIFT WEST OF THE REGION BUT SOME WEAK HEIGHT FALLS MAY BE STARTING TO SPREAD EAST AS A SHORTWAVE APPROACHES THE REGION FROM THE WEST. ISENTROPIC LIFT LOOKS TO BE FAIRLY WEAK AT THIS TIME WITH SOME WEAK LIFT ON THE 295K SURFACE. BUFR SOUNDINGS AT THIS TIME SHOW A WELL CAPPED ENVIRONMENT WITH NOT MUCH MOISTURE OR INSTABILITY ABOVE THE CAP. THEREFORE...THINK IT WILL BE DIFFICULT FOR STORMS TO DEVELOP THIS EARLY BUT NOT ENTIRELY IMPOSSIBLE. INSTEAD...THE MAIN FOCUS FOR THE OVERNIGHT PERIOD SHIFTS TO THE COMPLEX OF STORMS OR MCS THAT WILL DEVELOP ALONG THE COLD FRONT IN OKLAHOMA AND MARCH SOUTHEAST INTO NORTH TEXAS. THE BEST TIMING FOR THESE STORMS TO CROSS THE RED RIVER NEAR MONTAGUE AND COOKE COUNTIES IS AROUND 5-6 AM. THEREFORE...TRENDED HIGHEST POPS BACK TO THE WEST SOME AND ALSO TRIMMED ACROSS THE SOUTH SOME DUE TO THE SLIGHTLY SLOWER ARRIVAL TIME. BECAUSE OF THIS SLOWER TIME...ALSO ADJUSTED THE HIGHER POPS SUNDAY MORNING FARTHER NORTH AND WEST. AT THE TIME THE STORMS ARRIVE...THE CAP WILL BE WEAK OR ERODED AND THERE WILL BE A THREAT FOR SEVERE STORMS PRODUCING HAIL AND DAMAGING WINDS. SOME ADDITIONAL DECENT RAINFALL IS ALSO LIKELY WITH THIS STORM SYSTEM...ESPECIALLY OVER THE NORTHERN AND EASTERN COUNTIES. ADDITIONAL STORMS WILL ALSO BE POSSIBLE SUNDAY AFTERNOON ACROSS THE SOUTHERN COUNTIES WHERE THE FRONT WILL BE LOCATED IN THE AFTERNOON HOURS. THESE STORMS COULD POTENTIALLY BE SEVERE AS WELL. 82/JLD && .PREV DISCUSSION... /ISSUED 351 PM CDT SAT MAR 30 2013/ SOMEWHAT OF A COMPLEX SURFACE PATTERN IN PLACE ACROSS THE SOUTHERN PLAINS THIS AFTERNOON WHICH WILL AFFECT WHICH AREAS SEE THUNDERSTORMS OVER THE NEXT 12 HOURS. A BROAD SURFACE LOW PERSISTS ACROSS FAR WEST TEXAS NEAR LUBBOCK WITH WHAT HAS BEEN A QUASI STATIONARY FRONTAL BOUNDARY EXTENDING TO THE NORTHEAST INTO SOUTHERN KANSAS. THIS ELONGATED TROUGH WILL BECOME A WELL DEFINED COLD FRONT BY LATE TONIGHT AND BEGIN TO MOVE SOUTH INTO THE RED RIVER VALLEY. MEANWHILE A WELL DEFINED WARM SECTOR EXISTS FROM NEAR SAN ANGELO NORTHWARD TO NEAR OKLAHOMA CITY AND BACK SOUTHEAST INTO THE ARKLATEX. THERE IS ALSO ONE DISTINCT OUTFLOW BOUNDARY WHICH IS NOW ALSO MOVING INTO THE ARKLATEX WITH SCATTERED THUNDERSTORMS DEVELOPING ALONG IT. 20Z OBJECTIVE ANALYSIS INDICATES A MODERATELY UNSTABLE AIRMASS IN PLACE ACROSS NORTH TEXAS WITH SURFACE BASED CAPE AROUND 1500J/KG AND LITTLE CONVECTIVE INHIBITION REMAINING ESPECIALLY ACROSS THE EASTERN HALF OF THE CWA. TWO AMDAR VAPOR SOUNDINGS HOWEVER JUST CAME IN ABOUT 20 MINUTES AGO FROM DFW AIRPORT AND REVEALED THAT SUFFICIENT CONVECTIVE INHIBITION REMAINS IN PLACE. THE FLIGHT PATHS CAME IN FROM THE EAST WHERE THE CAP WAS OBSERVED SO THIS YIELDS HIGHER CONFIDENCE THAT CAPPING REMAINS IN PLACE FARTHER EAST THAN INDICATED BY OBJECTIVE ANALYSIS. A VEERED LOW LEVEL WIND PROFILE IS ALSO REINFORCING A WARM LAYER ALOFT ESPECIALLY ACROSS THE WESTERN COUNTIES THIS AFTERNOON. SO WHAT HAPPENS... WITH THE LACK OF ANY APPRECIABLE LARGE SCALE FORCING FOR ASCENT IN THE NEXT 6 HOURS IT APPEARS UNLIKELY THAT THUNDERSTORMS WILL DEVELOP ACROSS NORTH TEXAS THROUGH THIS EVENING. MESOSCALE FORCING ALONG THE OUTFLOW BOUNDARY TO THE EAST IS MORE THAN SUFFICIENT FOR THUNDERSTORM DEVELOPMENT TO CONTINUE IN THE ARKLATEX...AND WILL HAVE SOME 20 POPS ACROSS THE FAR NORTHEAST TO ACCOUNT FOR THIS. OTHERWISE...IT APPEARS THAT WE WILL HAVE TO WAIT UNTIL LATER TONIGHT FOR ADDITIONAL THUNDERSTORMS TO AFFECT THE AREA. THE ONE CAVEAT TO THIS IS THE FAR WESTERN COUNTIES. THE HIGH RES GUIDANCE AND TO A LESSER EXTENT THE GFS/NAM ALL APPEAR TO ATTEMPT TO CONVECT BY 00Z THIS EVENING. THIS APPEARS TO BE IN RESPONSE TO SURFACE HEATING WITH FORCING ALONG THE DRYLINE. CONFIDENCE IN THIS SCENARIO IS LOW NOW GIVEN THE VEERED LOW LEVEL WIND FIELDS AND A LACK OF SUBSTANTIAL CONVERGENCE. AFTER 00Z IT APPEARS THAT THE SURFACE WINDS MAY BACK MORE IN RESPONSE TO UPSTREAM HEIGHT FALLS. THIS COULD LOCALLY ENHANCE CONVERGENCE ACROSS THE WESTERN COUNTIES. IF ANYTHING WERE TO DEVELOP IN THIS AREA IT WOULD LIKELY BE SEVERE. THE MORE LIKELY SCENARIO FOR THUNDERSTORMS TONIGHT APPEARS TO BE IN RESPONSE TO INCREASING FORCING FOR ASCENT AS A SHORTWAVE MOVES THROUGH THE CENTRAL PLAINS AND HEIGHT FALLS OVERSPREAD THE REGION. THE COLD FRONT ACROSS OKLAHOMA WILL BEGIN TO MOVE SOUTH AND SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG IT. ADDITIONAL THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT EARLIER IN THE NIGHT ALONG A PRE-FRONTAL TROUGH WHERE CAPPING GETS SUFFICIENTLY WEAKENED IN RESPONSE TO INCREASING LIFT. ALL OF THIS IS LIKELY TO INITIATE ACROSS SOUTHERN OKLAHOMA AND MOVE SOUTH ACROSS THE RED RIVER. THE BEST TIMING FOR THE INITIAL CONVECTIVE DEVELOPMENT...IF IT CAN DEVELOP...APPEARS TO BE AROUND MIDNIGHT. IF CONVECTION FAILS TO INITIATE ALONG THIS PRE-FRONTAL TROUGH THEN THE MAIN SHOW SHOULD BE ALONG THE FRONT VERY LATE TONIGHT INTO EARLY SUNDAY MORNING. THE ATMOSPHERE REMAINS MODERATELY UNSTABLE WITH VERY STEEP LAPSE RATES SO THUNDERSTORMS WILL HAVE THE POTENTIAL TO BE SEVERE. IF THE EARLIER ROUND OF STORMS CAN DEVELOP...ITS SEVERE POTENTIAL WILL BE GREATER AS IT WILL HAVE AN UNTAPPED RESERVOIR OF INSTABILITY TO WORK WITH. IT IS LIKELY THAT THUNDERSTORMS THAT DEVELOP THAT LATE IN THE NIGHT WILL BE SLIGHTLY ELEVATED...HOWEVER WITH 1500-2000J/KG OF MUCAPE AND 40-50KTS OF DEEP LAYER SHEAR TO WORK WITH...ELEVATED SUPERCELLS ARE LIKELY. LARGE HAIL WILL BE THE MAIN THREAT...ALTHOUGH DAMAGING WINDS CAN EASILY MAKE IT TO THE GROUND DESPITE BEING SLIGHTLY ELEVATED. WILL HAVE POPS INCREASING THROUGH THE NIGHT TONIGHT WITH HIGHEST NUMBERS ALONG THE RED RIVER AND NORTHEAST COUNTIES. ONE OR MORE CLUSTERS OF THUNDERSTORMS SHOULD BE ONGOING EARLY EASTER MORNING ACROSS NORTH TEXAS. AS THE FRONT CONTINUES TO MOVE SOUTH THE THUNDERSTORMS WILL GRADUALLY SHIFT SOUTH AS WELL THROUGH THE DAY. BY AFTERNOON...THE ATMOSPHERE ACROSS THE SOUTHERN HALF OF THE CWA WILL BE UNSTABLE AND SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS THE SOUTHERN COUNTIES. THESE WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL AND DAMAGING WINDS. MONDAY APPEARS TO PROVIDE A BRIEF RESPITE FROM THE ACTIVE WEATHER WITH THE OLD FRONTAL BOUNDARY TO THE SOUTH AND WEAK RIDGING ALOFT. THE BREAK IS EXPECTED TO BE SHORT THOUGH AS A STRONG UPPER LOW MOVES INTO THE 4-CORNERS REGION. THE STRONGER FRONT ASSOCIATED WITH THIS SYSTEM WILL SLIDE SOUTH WITH STRONG ISENTROPIC ASCENT COMMENCING MONDAY NIGHT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED LATE MONDAY NIGHT. BETTER RAIN CHANCES ACROSS NORTH TEXAS WILL BE TUESDAY AND ESPECIALLY TUESDAY NIGHT AS THE LOW SLOWLY MOVES EAST. WILL HAVE HIGH POPS ACROSS THE ENTIRE CWA AS IT APPEARS VERY BENEFICIAL RAINFALL WILL OCCUR ACROSS THE REGION. THUNDERSTORM ACTIVITY IS EXPECTED TO BE ELEVATED AND MORE ISOLATED IN NATURE DURING THIS TIME...SO WIDESPREAD SEVERE WEATHER IS NOT EXPECTED AT THIS TIME. DID WARM TEMPS UP A BIT THROUGH MIDWEEK AS GUIDANCE IS NOT QUITE AS COLD WITH THE AIR COMING DOWN. IT WILL STILL BE CHILLY WITH HIGHS IN THE UPPER 50S AND LOWER 60S. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 62 74 53 76 54 / 50 70 10 10 40 WACO, TX 65 76 58 77 59 / 20 60 20 10 40 PARIS, TX 58 72 52 75 47 / 60 80 10 10 20 DENTON, TX 61 74 53 77 50 / 60 70 10 10 50 MCKINNEY, TX 61 73 53 75 52 / 60 80 10 10 40 DALLAS, TX 64 76 55 78 56 / 50 70 20 10 40 TERRELL, TX 63 74 54 76 56 / 50 80 20 10 30 CORSICANA, TX 63 76 58 77 59 / 20 70 20 10 30 TEMPLE, TX 64 78 58 79 61 / 20 60 20 10 30 MINERAL WELLS, TX 60 75 53 79 52 / 40 50 10 10 50 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/82
AREA FORECAST DISCUSSION
NWS TAUNTON MA
713 AM EDT SUN MAR 31 2013 .SYNOPSIS... AFTER A CHILLY START EARLY THIS MORNING...DRY AND MILD WEATHER IS EXPECTED FOR THE AFTERNOON AS HIGH PRESSURE MOVES OFF THE COAST. A COLD FRONT WILL BRING A PERIOD RAIN SHOWERS TO THE REGION TONIGHT...AND PERHAPS AN EMBEDDED THUNDERSTORM OR TWO. A SECONDARY COLD FRONT WILL LIKELY BRING A FEW SHOWERS TO THE REGION MON. COOL AIR AND GUSTY WINDS ARE EXPECTED THROUGH MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 7 AM UPDATE... ONLY MINOR ADJUSTMENTS TO THE FORECAST THIS MORNING. ADJUSTED TIMING OF SKIES TOWARD LATEST RAP WHICH SEEMS TO BE HANDLING THE CI DECK MOVING IN AHEAD OF AN OCCLUDED FRONT BETTER THAN MOST AVAILABLE GUIDANCE. OTHERWISE...MUCH OF THE REST OF THE FORECAST REMAINS ON TRACK. BROUGHT TEMPS AND DWPTS UP TO CURRENT TRENDS. PREVIOUS DISCUSSION... MOSTLY SUNNY SKIES FOR MUCH OF THE MORNING WILL GIVE WAY TO AN INCREASE IN CLOUDINESS FROM THE WEST THIS AFTERNOON. THIS A RESULT OF MID/HIGH LEVEL MOISTURE STREAMING OUT AHEAD OF AN APPROACHING COLD FRONT. THE BEST DYNAMICS AND FORCING WILL REMAIN WELL TO OUR WEST THROUGH THE AFTERNOON HOURS...SO EXPECT DRY WEATHER TO PREVAIL TODAY. ALTHOUGH ITS QUITE CHILLY VERY THIS MORNING...THE STRONG LATE MARCH SUN ANGLE ALONG WITH A RELATIVELY DRY AIRMASS IN PLACE WILL ALLOW FOR A QUICK RECOVERY. HIGH TEMPS SHOULD REACH INTO THE UPPER 50S TO NEAR 60 ACROSS MANY LOCALES. IT WILL BE COOLER ALONG THE IMMEDIATE SOUTH COAST WITH SOUTH TO SOUTHWEST WINDS BLOWING OFF THE COLD OCEAN. IT MAY ALSO BE COOLER ON THE VERY IMMEDIATE EASTERN MA COAST AS A RESULT OF LOCALIZED SEA BREEZES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... TONIGHT... THE COLD FRONT WILL MOVE ACROSS THE REGION TONIGHT AS A SECONDARY WAVE OF LOW PRESSURE DEVELOPS NEAR THE SOUTH COAST. THE FRONT HAS FAIRLY GOOD DYNAMICS ALONG WITH DECENT MOISTURE...SO EXPECT A BAND OF WIDESPREAD RAIN SHOWERS FOR SEVERAL HOURS. WHILE THE RAIN SHOULD ONLY LAST FOR A 3 TO 5 HOUR PERIOD IN A GIVEN LOCATION...IT MAY BE BRIEFLY HEAVY. IN ADDITION...TOTAL TOTAL VALUES RISE INTO THE LOW TO MID 50S ALONG WITH SHOWALTERS DROPPING CLOSE TO ZERO. THIS MAY BE JUST ENOUGH ELEVATED INSTABILITY FOR A FEW EMBEDDED THUNDERSTORMS WITH THE BEST CHANCE ALONG THE SOUTHEAST NEW ENGLAND COAST. WILL CONTINUE TO CARRY ISOLATED THUNDER IN THE FORECAST TO COVER THIS POTENTIAL. MONDAY... THE RAIN SHOWERS WILL HAVE LONG SINCE EXITED THE COAST BY DAYBREAK MONDAY. A FAIR AMOUNT OF SUN EARLY AND A MILD START SHOULD ALLOW MUCH OF THE REGION TO SEE HIGHS RECOVER INTO THE UPPER 50S AND LOWER 60S...ALTHOUGH IT WILL BE QUITE BREEZY. BY MON AFTERNOON...A SECONDARY COLD FRONT AND A POTENT SHORTWAVE WILL SWING ACROSS THE REGION. THIS LOOKS TO BE QUITE A DYNAMIC SETUP WITH STEEP MID LEVEL LAPSE RATES APPROACHING 7 TO 7.5 C/KM. THERE PROBABLY WILL BE A FEW HUNDRED J/KG OF SURFACE BASED CAPE ALONG WITH 100+ KNOT 250 MB JET. EXPECT SCATTERED SHOWERS TO DEVELOP AND THEY MAY CONTAIN LOCALLY GUSTY WINDS GIVEN DECENT TEMP/DEWPOINT SPREADS. HAVE ALSO INCLUDED A SLIGHT CHANCE OF THUNDER GIVEN THE STEEP MID LEVEL LAPSE RATES AND STRONG JET DYNAMICS. TEMPERATURES WILL FALL QUICKLY INTO THE UPPER 30S AND 40S BY EARLY MONDAY EVENING AS MUCH COLDER AIR WORKS INTO THE REGION BEHIND THE FRONT. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... HIGHLIGHTS... * GUSTY NORTHWEST WINDS TUE AND WED ESPECIALLY. * TEMPERATURES SEASONABLY COOL THROUGH WED AS WELL. * WILL HAVE TO WATCH COASTAL LOW FOR FRI. OVERVIEW AND MODEL PREFERENCES... 31/00Z MODEL GUIDANCE SUITE CONTINUES TO BE IN FAIRLY GOOD AGREEMENT REGARDING SYNOPTIC PATTERN THROUGH MUCH OF THE WEEK. GREENLAND BLOCK REMAINS IN PLACE. THE BIGGEST DIFFERENCES REMAIN WITH SRN STREAM ENERGY AND ITS SFC REFLECTION...A COASTAL LOW PRES WHICH WILL PASS S OF THE REGION. THE TRACK IS WHAT REMAINS IN QUESTION...AND IS LIKELY DEPENDENT ON THE CONTINUED GREENLAND BLOCK THE GUIDANCE SHOWS IN PLACE. WILL NEED TO KEEP AN EYE ON THIS...AS MODELS CONTINUE TO SWAP BACK AND FORTH AS TO WHETHER OR NOT IT EFFECTS THIS REGION. WILL CONTINUE USING GFS/ECMWF AS A BASELINE FOR MUCH OF THE FORECAST...BUT WILL LEAN CLOSE TO PERSISTENCE WITH THE FRI LOW PASSAGE AS PREVIOUS FORECAST SCENARIO SEEMS LIKE A GOOD STARTING POINT. ENSEMBLES ARE NOT MUCH HELP HERE...SO CHANCE TO SLIGHT CHANCE POPS SEEM GOOD FOR THAT TIME FRAME. DETAILS... TUE THRU THU... MOSTLY DRY DURING THIS PERIOD AS SLOW MOVING HIGH PRES AND UPPER LVL RIDGE GRADUALLY CREST OVER THE REGION. H85 TEMPS START ABOUT -10C TUE SUPPORTING TEMPS IN THE LOW TO MID 40S...-8C ON WED SUPPORTING TEMPS TOWARD THE UPPER 40S TO ABOUT -5C BY THU...SO TEMPS IN THE LOW TO MID 50S ARE LIKELY TO RETURN. TIGHT PRES GRADIENT WITH LOW LVL WINDS POSSIBLY MIXING TO 25-30KT AT TIMES...SO SFC WIND GUSTS OF 20-30 MPH ARE NOT OUT OF THE QUESTION ESPECIALLY TUE AND WED. FRI INTO FRI NIGHT... HIGH PRES SLIPS TO THE NE SETTING UP A POTENTIAL BLOCK...THE LOCATION OF WHICH WILL HAVE FAIRLY SIGNIFICANT IMPACT ON THE FINAL TRACK OF A COASTAL LOW PRES S AND E OF SRN NEW ENGLAND. LATEST GFS AND SOME ECENS AND GEFS ENSEMBLE MEMBERS ARE NOW BRINGING THE THIS JUST SE OF THE 40/70 BENCHMARK...WITH SOME PRECIPITATION SPREADING FROM SRN CT NE TO ABOUT BOS. THIS SOLUTION IS ALSO A BIT COLDER...WITH H85 TEMPS DIPPING BELOW 0C N OF THE CAPE COD CANAL...WHICH SUGGEST SOME WET SNOW POSSIBLE IN THE INTERIOR COASTAL PLAIN. HOWEVER...ECWMF AND MANY GEFS/ECENS MEMBERS ARE A BIT FURTHER OFFSHORE AND WARMER. GIVEN THE DIFFERENCES HERE...WILL CONTINUE TO ERR TOWARD POPS SUGGESTED BY PREVIOUS FORECASTER...WHICH SUGGESTS CHANCE POPS ALONG THE IMMEDIATE COAST AND SLIGHT CHANCE POPS UP TO ABOUT THE MASS PIKE AS THIS IS A GOOD MIDDLE GROUND. THE TIMING DIFFERENCES SEEM TO BE COMING TOGETHER WITH THE LATEST GFS SLOWING A BIT AND THE ECMWF SPEEDING UP SOMEWHAT...SUGGESTING THE CLOSEST PASS IS NOW MORE LIKE FRI NIGHT. IN TERMS OF THERMAL PROFILES WILL USE A 50-50 BLEND OF THE WARMER ECMWF AND COLDER GFS FOR THE TIME BEING...WHICH STILL DOES INTRODUCE AT LEAST THE POTENTIAL FOR A RAIN-SNOW MIX AWAY FROM THE COAST DURING THE OVERNIGHT HOURS. HOWEVER...DURING THE DAY FRI...BL TEMPS MAY PRECLUDE ANY SNOW CHANCES UNLESS A COLDER NORTHERLY DRAW APPEARS LIKELY OR DYNAMIC COOLING IS ENOUGH TO OVERCOME THIS TOWARD THE EVENING. A LOT OF PLAYERS STILL YET TO COME IN LINE. SAT... GUIDANCE CONTINUES TO SUPPORT...AFTER ANY POTENTIAL PRECIP...THAT HIGH PRES BUILDS IN FOR THE EARLY HALF OF THE WEEKEND. MOSTLY DRY WEATHER AND TEMPS NEAR SEASONABLE LOOK REASONABLE GIVEN THE THERMAL PROFILE. SUN... MODELS ARE ACTUALLY IN DECENT AGREEMENT THAT A FAST MOVING MID LVL SHORTWAVE WILL PASS THROUGH THE ZONAL JET SET UP JUST TO THE N OF THE AREA...HOWEVER THE SFC REFLECTION SPREAD IS QUITE BROAD. WILL ERR TOWARD A MORE UNSETTLED SOLUTION FOR SUN. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW...HIGH CONFIDENCE TODAY WITH MODERATE CONFIDENCE TONIGHT. HIGH CONFIDENCE RETURNS ON MONDAY. TODAY...HIGH CONFIDENCE IN VFR CONDITIONS. SOUTHERLY WIND GUSTS AROUND 20 TO 25 KNOTS EXPECTED THIS AFTERNOON. TONIGHT...MVFR CONDITIONS DEVELOP FROM WEST TO EAST WITH EVEN SOME IFR CONDITIONS LIKELY FOR A TIME. THIS A RESULT FROM A BAND OF RAIN SHOWERS WHICH MAY BE BRIEFLY HEAVY AHEAD OF AN APPROACHING COLD FRONT. A FEW EMBEDDED THUNDERSTORMS ARE ALSO POSSIBLE WITH THE BEST CHANCE ACROSS THE SOUTHEAST NEW ENGLAND COAST. MONDAY...MAINLY VFR CONDITIONS EARLY IN THE DAY WITH GUSTY WEST WINDS OF 25 TO 30 KNOTS. CAN/T RULE OUT SOME BRIEF MVFR CONDITIONS ALONG WITH A COUPLE OF SHOWERS AS A SECONDARY COLD FRONT MOVES THROUGH THE REGION. KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS TODAY. STILL EXPECTING AN ESE SEABREEZE ESPECIALLY THIS MORNING. HIGH CONFIDENCE IN AT LEAST A PERIOD OF MVFR CONDITIONS TONIGHT WITH BRIEF IFR CONDITIONS ALSO POSSIBLE. THIS IN ASSOCIATION WITH A BAND OF SHOWERS AND A LOW PROBABILITY OF AN ISOLATED THUNDERSTORM. KBDL TAF...HIGH CONFIDENCE VFR CONDITIONS TODAY. HIGH CONFIDENCE IN AT LEAST A PERIOD OF MVFR CONDITIONS TONIGHT WITH BRIEF IFR CONDITIONS ALSO POSSIBLE. THIS IN ASSOCIATION WITH A BAND OF SHOWERS AND A LOW PROBABILITY OF AN ISOLATED THUNDERSTORM. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY... MONDAY NIGHT THROUGH THURSDAY...HIGH CONFIDENCE. VFR. WEST TO NORTHWEST WINDS GUST TO AROUND 25 TO EVEN AN ISOLATED 30 KNOTS TUESDAY AND WEDNESDAY. && .MARINE... TODAY...HIGH CONFIDENCE THAT WINDS/SEAS REMAIN BELOW SCA THRESHOLDS. HOWEVER...SOUTHERLY WINDS MAY GUST TO 20 KNOTS THIS AFTERNOON AS HIGH PRESSURE MOVES EAST OF THE REGION. TONIGHT...HIGH CONFIDENCE IN A PERIOD OF SOUTH TO SOUTHEAST SCA WIND GUSTS/SEAS ACROSS MOST OF OUR OPEN WATERS. PREVIOUS SCA HEADLINES FOR ALL OPEN WATERS CONTINUES. THIS A RESULT OF AN INCREASING PRESSURE GRADIENT AHEAD OF AN APPROACHING COLD FRONT AND WAVE OF LOW PRESSURE. A BAND OF RAIN SHOWERS WILL ACCOMPANY THE FRONT AND CAN/T RULE OUT A FEW ISOLATED THUNDERSTORMS ESPECIALLY ACROSS THE SOUTHEAST WATERS. MONDAY...HIGH CONFIDENCE IN SCA WIND GUSTS OF 25 TO 30 KNOTS ACROSS THE WATERS ESPECIALLY NEAR SHORE WITH EXCELLENT MIXING. HAVE EXTENDED SCA FOR ALL OPEN WATERS THROUGH MON AFTERNOON. LATER SHIFTS WILL ALSO PROBABLY NEED TO ISSUE SCA FOR BOSTON HARBOR AND NARR BAY...BUT SINCE ITS WAS 3RD PERIOD HELD OFF ON IT ON THIS SHIFT. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY... MODERATE TO HIGH CONFIDENCE. MONDAY THROUGH WEDNESDAY... PROLONGED PERIOD WITH NW WIND GUSTS 25 TO 30 KT POSSIBLE. LOW PROBABILITY OF AN OCCASIONAL GALE FORCE GUST. SEAS WILL BE 5-7 FT ON OUTER WATERS. SMALL CRAFT ADVISORIES WILL BE NEEDED. THURSDAY...DIMINISHING WINDS AND SEAS. SMALL CRAFT HEADLINES MAY LINGER ON THE OUTER WATERS DURING THE MORNING. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT MONDAY FOR ANZ231>235-237-250-254>256. SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 8 PM EDT MONDAY FOR ANZ251. && $$ SYNOPSIS...FRANK/DOODY NEAR TERM...FRANK/DOODY SHORT TERM...FRANK LONG TERM...DOODY AVIATION...FRANK/DOODY MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1022 AM EDT SUN MAR 31 2013 .UPDATE... A FEW SHOWERS LINGER OVER TOOMBS COUNTY BUT THESE ARE MOVING QUICKLY TO THE EAST. AN AREA OF SHOWERS AND ISOLATED TSTORMS OVER CENTRAL AL IS HOLDING TOGETHER AND SHOULD MOVE INTO WEST CENTRAL GA AROUND NOON. MODELS NOT HANDLING THIS AS WELL...ALTHOUGH THE HRRR DOES HAVE THE AREA OF SHOWERS BUT TOO FAR NORTH. THE 2ND WAVE OVER OK/AR STILL PROGGED TO MOVE INTO THE CWA LATE THIS AFTERNOON/THIS EVENING. TEMPS STILL LOOK ON TARGET. EVEN WITH THE CLOUDS THERE IS STILL SOME GOOD WAA TODAY. OTHER THAN ADJUSTING THE POPS...NO OTHER CHANGES PLANNED. && .SHORT TERM /TODAY THROUGH MONDAY/... /ISSUED AT 740 AM EDT SUN MAR 31 2013/ SHORT WAVE CURRENTLY MOVING THROUGH OHIO/TN VALLEY AREA. SHOWERS ASSOCIATED WITH THIS FEATURE WILL CONTINUE TO MOVE EAST THROUGH THE CWA THIS MORNING. SHOWERS SHOULD DIMINISH THROUGH THE MORNING AND MODELS INDICATE A BREAK BETWEEN THIS WAVE AND THE NEXT ONE WHICH SHOULD AFFECT US STARTING THIS AFTERNOON. HAVE INCREASED POPS AGAIN STARTING AROUND 18Z AND CONTINUE WITH LIKELY POPS FOR MUCH OF THE CWA THROUGH 06Z MONDAY. INSTABILITY INCREASES ALSO DURING THIS AFTERNOON WITH BEST CAPE AND LIFTED INDEX VALUES 18Z TODAY THROUGH 06Z MONDAY. HAVE CONTINUED WITH MENTION OF THUNDER DURING THAT TIME. UPPER TROUGH DEEPENING OVER THE NORTHERN STATES SHOULD PUSH A SURFACE BOUNDARY INTO NORTH GA LATE TONIGHT AND INTO MONDAY. SOME DRYING SHOULD OCCUR BEHIND THIS BOUNDARY AND HAVE ENDED SHOWERS FROM THE NORTH MONDAY MORNING WITH SOME POPS CONTINUING THROUGH THE CENTRAL ZONES INTO THE AFTERNOON. TEMPERATURES CONTINUE WARM THROUGH THE SHORT TERM AND HAVE TAKEN A BLEND OF THE MAV/MET. 41 .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... /ISSUED AT 740 AM EDT SUN MAR 31 2013/ NEXT MAIN RAIN EVENT WILL ENCOMPASS THE SECOND HALF OF THE WEEK. GFS/EUROPEAN SIMILAR WITH BRINGING RAIN TO THE AREA POSSIBLY AS EARLY AS TUESDAY NIGHT/WEDNESDAY BUT MORE SO WEDNESDAY NIGHT INTO FRIDAY. A WARM FRONT DEVELOPS ALONG THE GULF COAST WITH OVERRUNNING MOIST FLOW SETTING UP. THE MAIN DIFFERENCE BETWEEN THE GFS AND EUROPEAN IS THE EUROPEAN BRINGS SURFACE LOW PRESSURE ACROSS CENTRAL TO S GA THURSDAY NIGHT AND FRIDAY WHILE THE GFS TAKES THE SURFACE LOW ACROSS N FL. GFS BRINGS ONLY MINIMAL MUCAPE INTO CENTRAL GA THURSDAY/THURSDAY NIGHT. IF THE EUROPEAN SURFACE SOLUTION COMES TO PASS THE CHANCES FOR THUNDERSTORMS WOULD BE GREATER WITH THE WARM FRONT POSSIBLY GETTING INTO CENTRAL GA WITH A LOW END THREAT FOR SEVERE WEATHER. EITHER WAY A GOOD RAIN EVENT WITH 1 TO 2 INCHES ACROSS CENTRAL GA. THE UPPER TROUGH MOVES TO THE AREA FRIDAY WITH THE GFS A LITTLE FASTER WITH THE TROUGH AND MOISTURE EXITING THAN THE EUROPEAN. A DAMPENING SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE MOVE TO THE AREA SATURDAY WITH DRY CONDITIONS EXPECTED AND THIS LOOKS TO CONTINUE FOR SUNDAY. BDL && .AVIATION... 12Z UPDATE... SEVERAL WAVES OF LOW PRESSURE WILL MOVE EAST ALONG A STALLED FRONT THROUGH SUNDAY....BRINGING ROUNDS OF SHOWERS ACROSS THE FORECAST AREA. EXPECT VARIABLE CEILINGS THROUGH THE REMAINDER OF THE MORNING WITH SOME AREAS OF IFR UNTIL 14Z. CEILINGS IMPROVING TO VFR AFTER 14Z BUT SHOWERS AND A FEW THUNDERSTORMS DEVELOPING AGAIN BY 18Z AND CONTINUING INTO THE EVENING. WINDS SOUTHWEST 10KT WITH SOME GUSTS TO NEAR 18Z MAINLY AFTER 18Z. //ATL CONFIDENCE...12Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. 41 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 71 53 75 46 / 40 60 10 10 ATLANTA 70 54 73 50 / 50 60 10 10 BLAIRSVILLE 63 47 69 39 / 50 60 10 20 CARTERSVILLE 69 50 72 43 / 60 60 10 10 COLUMBUS 76 58 77 52 / 50 70 30 5 GAINESVILLE 69 51 74 47 / 40 60 10 10 MACON 76 57 77 48 / 40 70 30 5 ROME 70 50 73 43 / 60 60 10 20 PEACHTREE CITY 71 52 74 45 / 50 60 10 5 VIDALIA 78 60 77 53 / 30 70 60 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...41 LONG TERM....BDL AVIATION...41
AREA FORECAST DISCUSSION
NWS PADUCAH KY
702 AM CDT SUN MAR 31 2013 .UPDATE... ISSUED AT 701 AM CDT SUN MAR 31 2013 LATEST RADAR TRENDS SHOW ANY THUNDER THREAT GETTING SHUNTED TO OUR WEST AND SOUTHWEST. THE FRESHEST DEVELOPMENT IS IN NORTHERN ARKANSAS...WHICH MAY SPELL A RAPID END TO THE MISSOURI CONVECTION EARLY THIS MORNING. SOME SHORT TERM GUIDANCE PUSHES THE NORTHERN ARKANSAS CONVECTION MORE TO THE EAST...POTENTIALLY IMPACTING OUR ENTIRE SOUTHERN BORDER WITH TIME THROUGH THE DAY. BEST GUESS IS THAT AREAS ALONG AND WEST OF A LINE FROM MARBLE HILL MISSOURI TO FULTON KENTUCKY LINE COULD SEE SOME TANGIBLE SHOWERS THIS MORNING. UPDATED TO BRING CHANCE POPS SOUTHEAST ACROSS THIS AREA THROUGH THE MORNING. AREAS NEAR THE TENNESSEE BORDER COULD SEE A STRAY SHOWER EARLY THIS AFTERNOON. THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z TAF ISSUANCE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 406 AM CDT SUN MAR 31 2013 CONSIDERED A DENSE FOG ADVISORY FOR WESTERN PORTIONS OF SOUTHEAST MISSOURI DUE TO KPOF REPORTING 1/2 MILE OR LESS...BUT IT SEEMS TO BE IMPROVING A BIT IN THE LAST HOUR AND WE HAVE LITTLE CLUE HOW WIDESPREAD IT IS. WILL KEEP AN EYE ON IT...BUT FOR NOW WILL JUST LET IT BE. WEAK ECHOES FOR LIGHT RAIN HAVE JUST ABOUT PUSHED EAST OF THE EVANSVILLE TRI STATE...BUT THERE MAY BE JUST A BIT LINGERING IN THE KOWB AREA. THIS SHOULD COME TO AN END SHORTLY. OF GREATER CONCERN IS THE AREA OF SHOWERS AND THUNDERSTORMS MOVING EAST SOUTHEAST ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI. HAD TO LEAN ON THE HRRR MODEL SIMULATED REFLECTIVITY TO REPRESENT THIS IN THE GRIDS. IN GENERAL WOULD EXPECT THE AREA TO WEAKEN AS IT MOVES INTO OUR REGION JUST AFTER SUNRISE...SO WILL HAVE 20-30 POPS FOR NOW...GENERALLY SWEEPING ACROSS OUR SOUTHWEST HALF 14Z- 20Z. THIS WEAKENING TREND IS SUPPORTED BY THE 06Z NAM...WHICH KEEPS ANY INSTABILITY TO OUR WEST AND SOUTHWEST. WILL HAVE TO KEEP A CLOSE EYE ON THIS SITUATION AS WELL AND BE PREPARED TO UPDATE IF/WHEN IT BECOMES NECESSARY. TEMPERATURES EARLY THIS MORNING ARE NEARLY STEADY...SO WE WILL HAVE A MILD START TO THE DAY...WHICH IS GOOD BECAUSE THE LOW CLOUDS/FOG AND EVENTUALLY SOME SHOWERS WILL DELAY WARMING THROUGH THE MORNING. TRIED TO CAPTURE THIS TREND IN THE TEMPERATURE GRIDS...BUT WE SHOULD JUMP UP WELL INTO THE 60S WITH SOME SUNSHINE THIS AFTERNOON. STAYED CLOSE TO CONSENSUS. LIKE THE 00Z AND 06Z NAM WITH THE REAL COLD FRONT/SURFACE HIGH SURGE THROUGH THE AREA LATE TONIGHT AND MONDAY...AS IT SHOULD HANDLE THE SHALLOW COLD AIRMASS BETTER THAN THE LESSER RESOLVED GFS. THE NAM DOES GENERATE SOME VERY MEAGER QPF OVER THE EVANSVILLE TRI STATE TONIGHT WITH THE INITIAL WIND SHIFT...BUT THE GFS IS DRY. DECIDED TO MENTION SOME SPRINKLES IN THAT AREA THROUGH THE NIGHT...BUT DID NOT INTRODUCE A MEASURABLE POP. CONSENSUS OF GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON TEMPERATURES TONIGHT. TEMPERATURES ONLY FALL INTO THE UPPER 30S IN THE NORTH...SO LITTLE CHANCE OF FLURRIES WITH THE SPRINKLES TONIGHT. FOR MONDAY...THE MODELS CONTINUE TO TREND DRIER AND DRIER FOR OUR AREA. SIMILAR TO TONIGHT...DECIDED TO JUST PLASTER A CHANCE OF SPRINKLES ACROSS THE ENTIRE AREA THROUGH THE DAY...IN LIEU OF A VERY SMALL MEASURABLE POP. TEMPERATURES WILL SUPPORT ALL LIQUID THROUGH THE DAY. FIGURE WITH THE SURGE CONSISTENTLY ADVERTISED IN THE NAM RUNS...THAT TEMPERATURES WILL BE COOLER THAN MOST GUIDANCE INDICATES. STAYED ON THE LOW SIDE OF GUIDANCE CLOSER TO THE NAM/MET...BUT THAT MAY NOT BE COOL ENOUGH. MONDAY NIGHT WILL BE DRY...BUT WE WILL REMAIN IN CYCLONIC WEST NORTHWEST FLOW ALOFT...SO CANNOT RULE OUT SOME LIGHT PRECIPITATION...ESPECIALLY OVER OUR SOUTHWEST MONDAY NIGHT INTO TUESDAY. THE GFS IS THE MOST AGGRESSIVE IN GENERATING LIGHT QPF WITH SOME FRONTOGENETIC FORCING IN THE 850-700MB LAYER IN THE FAR SOUTHWEST. INTRODUCED SOME VERY SMALL POPS NEAR THE ARKANSAS BORDER AND THE BOOT HEEL REGION JUST TO BE SAFE. LATELY...IF THERE IS ANY CHANCE OF US GETTING WET IT SEEMS TO HAPPEN. TEMPERATURES IN THAT AREA SHOULD BE NO LOWER THAN THE MIDDLE 30S...SO KEPT THIS ALL RAIN AS WELL. CONSENSUS TEMPERATURES LOOKED FINE MONDAY NIGHT AND TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 406 AM CDT SUN MAR 31 2013 THIS EXTENDED PERIOD FOR THIS FORECAST ISSUANCE WILL SERVE AS THE TRANSITION OF EXTREMES IN TEMPERATURE FROM NEAR RECORD LOWS WEDNESDAY MORNING TO ABOVE NORMAL /MIDDLE 60S/ HIGHS NEXT WEEKEND. GIVEN THE BELOW NORMAL TEMPERATURES WE HAVE BEEN EXPERIENCING IN MARCH...TEMPERATURES AT OR ABOVE NORMAL WILL BE A WELCOME CHANGE. THE ONLY WEATHER MAKER OF CONSEQUENCE WILL OCCUR THURSDAY/THURSDAY NIGHT. ANY MEASURABLE POPS AND WEATHER /GENERALLY SLIGHT IN CATEGORY/ WILL BE LIMITED TO WEST KENTUCKY AND A SMALL PART OF THE SOUTHEAST MISSOURI BOOTHILL. THE SOURCE REGION FOR THIS SYSTEM IS THE CLOSED LOW CURRENTLY OFF THE CALIFORNIA COAST. THIS FEATURE IS EXPECTED TO PUSH TOWARD THE CENTRAL ROCKIES AND DIVE EAST-SOUTHEAST INTO THE LOWER MISSISSIPPI VALLEY. DURING THE PAST 3-4 DAYS...THE NORTHERN EDGE OF THIS CLOSED LOW/WAVE HAS BEEN FORECAST BY THE GFS/ECMWF/GEM GUIDANCE TO SKIRT ALONG THE SOUTHERN BORDER OF THE WFO PAH FORECAST AREA. THERE HAS BEEN ENOUGH MODEL RUNS TO STILL INDICATE THAT VERY FEW LOCATIONS WILL SEE ANY RAIN...IF ANY...ON THURSDAY. THE MAIN IMPACT WILL BE CLOUD COVER...WITH A SHARP DEMARCATION LINE ON THE NORTHERN EDGE OF THE DEFORMATION ZONE ASSOCIATED WITH THE LOW/WAVE. NORTHEAST WINDS DURING THIS TIME PERIOD MAY TEMPER HIGHS SOMEWHAT. WITH HIGH PRESSURE DOMINATING THE REGION THROUGH MOST OF THE PERIOD...CLOUD COVER WILL BE MINIMAL OUTSIDE OF THE DISTURBANCE ON THURSDAY. THIS WILL SET THE STAGE FOR GOOD INSOLATION/DRY AIR ADVECTION AND EVAPORATION. A MANUAL UPWARD ADJUSTMENT WAS MADE TO THE MAX TEMPERATURES FROM FRIDAY THROUGH SUNDAY TO ACCOUNT FOR A LARGER DIURNAL RANGE /25-27 DEGREES F/IN TEMPERATURES WITH THE DRIER AIR IN PLACE ACROSS THE WFO PAH FORECAST AREA. AS A SIDE NOTE...MIN FORECAST TEMPERATURES WEDNESDAY MORNING LOOK LIKE THEY MAY BE ONE TO TWO DEGREES HIGHER THAN THE RECORD TEMPERATURES ON THE BOOKS. SUBTLE MICRO-CLIMATE CHANGES AROUND THE OBSERVATION SITES WILL DETERMINE WHETHER ANY RECORDS ARE TIED OR SET WEDNESDAY MORNING. && .AVIATION... ISSUED AT 701 AM CDT SUN MAR 31 2013 IFR CONDITIONS TO BEGIN WITH WILL DISSIPATE IN FAVOR OF VFR CEILINGS AS A BAND OF CLOUDS FROM 1500 FT TO 6KFT MOVES ACROSS THE ENTIRE AREA THIS MORNING. COULD SEE SOME SPRINKLES OUT OF THESE CLOUDS AS THEY PASS OVER KCGI AND KPAH. WINDS WILL BE HIGHLY VARIABLE IN SPACE AND TIME TODAY...BUT THEY WILL GENERALLY BE LIGHT. SHOULD SEE A LIGHT SOUTH SOUTHEAST WIND DEVELOP BY SUNSET...AS A SIGNIFICANT COLD FRONT APPROACHES. THE FRONT WILL PUSH SOUTH THROUGH THE AREA OVERNIGHT. KEPT NORTH POST FRONTAL WINDS RATHER LIGHT...AS THE MORE SIGNIFICANT SURFACE PRESSURE SURGE WILL BE DELAYED A FEW HOURS. NOT LOOKING FOR ANY CEILINGS OTHER THAN VFR BEYOND THIS MORNING. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS SHORT TERM...DRS LONG TERM...SMITH AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
928 AM EDT SUN MAR 31 2013 .SYNOPSIS... A CROSSING FRONT WILL BRING RAIN ON SUNDAY AND USHER IN COLD TEMPERATURES FOR MUCH OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FOR THIS MORNINGS UPDATE...ONLY MADE SOME SLIGHT TIMING CHANGES TO THE POPS AND TEMPERATURES BASED OFF OF THE MOST RECENT RADAR COVERAGE AND HI RES MODEL TRENDS. THE HRRR AND THE RUC CONTINUE TO SUGGEST...AS THE MID-SHIFT DISCUSSED BELOW...THAT THE GREATEST SYNOPTIC LIFT AND QPF WILL REMAIN OVER MUCH OF THE SOUTHEASTERN HALF OF OUR ZONES TODAY. THE ONLY THING TO NOTE: THE HRRR MAY BE JUST A BIT SLOW ON IT`S COLD FRONT TIMING...AS IT IS ALREADY MAKING IT INTO WESTERN OHIO. WILL CONTINUE TO MONITOR THE FRONTAL TIMING AND ADJUST AS NECESSARY. OTHERWISE...LEFT FORECAST AS IS FOR NOW. PREVIOUS DISCUSSION FOLLOWS... TODAY`S SYSTEM LOOKS TO START TO BRING LIFT INTO THE SOUTHWESTERN PORTIONS OF THE AREA SHORTLY AFTER SUN UP...WITH THE CONSENSUS OF THE TRACK OF STRONGEST LIFT AND HENCE QPF ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA THROUGH THE DAY. POPS AND QPF WERE ADJUSTED FOR A LATER ONSET AS WELL AS TO FOCUS ON THE SOUTHEASTERN ZONES. ALSO OF NOTE IS THAT THE INSTABILITY THAT THE NAM HAD INDICATED OVER THE AREA ON YESTERDAY`S 00Z RUNS HAS BASICALLY DISAPPEARED WITH THIS CYCLE. WHILE SOME POSITIVE AREA IS NOTED...IT IS GENERALLY WELL BELOW THE LAYER IN WHICH IT WOULD BE REQUIRED FOR CHARGE SEPARATION. ADDITIONALLY...SINCE THE BULK OF THE SYNOPTIC LIFT TRAVERSES AREAS TO THE SOUTH OF US...STRONG LIFT REALLY IS LACKING. WHILE RAIN SHOWERS ARE PRETTY MUCH A FOREGONE CONCLUSION...THUNDERSTORMS STILL SEEM QUITE UNLIKELY TODAY. TEMPERATURES WERE ADJUSTED GENERALLY DOWNWARD SLIGHTLY. SIGNIFICANT CLOUD COVER COMBINED WITH DEVELOPING RAINFALL SHOULD MANAGE TO RESTRICT OUR DIURNAL RISES SLIGHTLY...HOWEVER HIGHS NEAR NORMAL IN THE 50S ARE STILL EXPECTED. FRIES && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... THE INITIAL COLD FRONT IS EXPECTED TO BE EAST OF THE REGION TONIGHT. ADDITIONALLY...A SECONDARY COLD FRONT LARGELY STACKED IN THE 850-500 MB LAYER LOOKS TO MOVE INTO THE AREA BY LATE TONIGHT. THAT WILL BRING BOTH A SECONDARY SHOT OF COLDER AIR AS WELL AS A SECONDARY SHOT AT FRONTOGENETICAL LIFTING. WHILE QPF VALUES WITH THIS FRONT WILL LIKELY BE QUITE LIGHT...POPS WERE INCREASED FOR LOW END QPF AND A RAIN TO SNOW SHOWER TRANSITION AS IT MOVES FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA THROUGH MONDAY. THE MODEL CONSENSUS HAS REALLY CONVERGED ON BRINGING MUCH DRIER AIR INTO THE AREA BEHIND THE SECONDARY FRONT. SO WHILE SHOWERS ARE LIKELY TO TRANSITION TO SNOW...THEY SHOULD NOT PERSIST LONG BEHIND THE PASSAGE. DEWPOINTS FROM BOTH EXPLICIT...ENSEMBLE...AND MOS SOURCES DROP TOWARD 10F BY MID-WEEK...SO POPS WERE ESSENTIALLY REMOVED FROM THE FORECAST. HOWEVER...WITH DRY AIR MOVING IN BRINGING CLEAR SKIES...OVERNIGHT LOW WERE TRIMMED A FEW DEGREES...AND MAY LIKELY STILL BE TOO WARM. FRIES && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... MODEL AND ENSEMBLE SOLUTIONS ALL FAVOR A DRY EXTENDED FORECAST. A WEAK SYSTEM LOOK SUPPRESSED TO OUR SOUTH IN THE SPLIT FLOW PATTERN LATE IN THE WEEK...WITH OPERATIONAL GUIDANCE FAVORING A TRACK INTO THE D.C. REGION. WHILE SOME OF THIS MAY CLIP THE SOUTHEASTERN PORTIONS OF THE FORECAST AREA...THE PREPONDERANCE OF THE PAST SEVERAL MODEL CYCLES SUGGESTS THAT IT SHOULD REMAIN LARGELY TO OUR SOUTHEAST. AS SUCH...THE ENTIRE EXTENDED FORECAST LOOKS FAIRLY DRY FOR THE MOMENT. TEMPERATURES THROUGH THE EXTENDED MODERATE TOWARD NORMAL. WITH A SPLIT FLOW LIKELY TO BE IN PLACE...OUR AREA SHOULD REMAIN LARGELY LOCKED BETWEEN THE NORTHERN AND SOUTHERN STREAM. AS A RESULT...NO WILD SWINGS ABOVE OR BELOW NORMAL ARE EXPECTED AT THIS TIME. FRIES && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... A GENERAL VFR FORECAST IS EXPECTED THROUGH MOST OF THE FORECAST PERIOD. THERE WILL BE PERIODS OF TEMPO MVFR RESTRICTIONS WITH SHOWERS BEGINNING DURING THE LATE MORNING HOURS AND CONTINUING THROUGH MOST OF THE AFTERNOON. LATER FORECASTS CAN BETTER ADDRESS THE TIMING OF THE RESTRICTIONS. LIGHT AND VARIABLE WINDS WILL VEER TO THE SOUTH-SOUTHWEST AND INCREASE TO 10KTS. HIGHER GUSTS ARE POSSIBLE IN THE AFTERNOON AT ZZV. .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RAIN SHOWERS WILL BECOME MORE SCT AND ISO SUNDAY NIGHT AND MONDAY AND MAY MIX WITH OR CHANGE OVER TO SNOW SHOWERS AS COLD NORTHWEST FLOW DEVELOPS BEHIND THE FRONT. A FEW RESTRICTIONS ARE POSSIBLE IN THE SCATTERED SNOW SHOWERS THROUGH MONDAY. SOME FLURRIES MAY CONTINUE INTO TUESDAY MORNING BUT GENERAL VFR CONDITIONS CAN BE EXPECTED THROUGH THURSDAY AS HIGH PRESSURE BUILDS OVR THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1000 AM EDT SUN MAR 31 2013 .SYNOPSIS... ISSUED AT 330 AM EDT SUN MAR 31 2013 TEMPERATURES WILL AVERAGE NEAR NORMAL TODAY BEFORE ANOTHER ROUND OF UNSEASONABLY COLD AIR MOVES IN TONIGHT THROUGH TUESDAY. TEMPERATURES WILL AVERAGE TEN TO FIFTEEN DEGREES BELOW NORMAL MONDAY THROUGH TUESDAY WITH A FEW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES FROM THE EARLY MORNING HOURS MONDAY THROUGH TUESDAY MORNING. TEMPERATURES WILL MODERATE MID TO LATE WEEK AND RETURN TO NEAR NORMAL BY THURSDAY AND FRIDAY. DRY WEATHER IS ANTICIPATED MID TO LATE WEEK AS HIGH PRESSURE BUILDS IN. && .SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON) ISSUED AT 1000 AM EDT SUN MAR 31 2013 LOOKING AT A FAIR AMOUNT OF EARLY AFTERNOON SUNSHINE AS LOW LEVEL MOISTURE MIXES OUT THIS MORNING. STILL LOOKING AT EARLY AFTERNOON TEMPS RANDING FROM THE UPPER 40S AT THE COAST TO MID 50S INLAND. ALSO LIKE HI RES GUIDANCE SUGGESTING A COUPLE BANDS OF LIGHT SHRA / SPRINKLES SPREADING WEST TO EAST AFTER 5PM. SHRA ACTIVITY WILL BE ALONG AND AHEAD OF LEADING EDGE OF ARCTIC AIR. EXPECT WESTERLY WIND GUSTS TO 30 MPH INLAND THIS AFTERNOON WITH INITAL CAA AND MIXING. INITIALLY...STABLE TEMPERATURE STRATIFICATION OVER THE LAKE WILL INHIBIT GUSTINESS. A SECOND ROUND OF WIND GUSTS TO 35 MPH WILL AFFECT ALL AREAS AS THE ARCTIC AIR MOVES IN EARLY THIS EVENING. SCATTERED WNW FLOW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL DEVELOP VERY LATE TONIGHT AND CONTINUE MONDAY AS H8 TEMPS FALL TO -13 TO -15 C BY 12Z MON. HOWEVER WITH A VERY DRY AIRMASS ADVECTING IN AND LACK OF BETTER MOISTURE OR UPSTREAM RH THIS WILL NOT AMOUNT TO ANYTHING (TRACE AMOUNTS TO JUST A FEW TENTHS OF AN INCH OF SNOW FROM THE EARLY MORNING HOURS MONDAY THROUGH EARLY TUESDAY). ANY LINGERING FLURRIES EARLY TUESDAY SHOULD END WITH AN EVEN DRIER AIRMASS IN PLACE LATER ON TUESDAY AND AS H8 TEMPS BEGIN TO MODERATE A BIT BY TUESDAY AFTN. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 330 AM EDT SUN MAR 31 2013 AFTER THE EARLY WEEK COLD BLAST... IT LOOKS LIKE WINTER WILL LOOSEN ITS GRIP ON THE GREAT LAKES REGION. MEDIUM RANGE GUIDANCE IS STARTING TO SHOW SOME CONSISTENCY THAT THE TROUGHING WHICH HAS PERSISTED MOST OF MARCH OVER THE ERN U.S. WILL FINALLY LIFT OUT. FOR THE MID TO LATE WEEK PERIOD THE UPPER FLOW WILL BE ZONAL WHICH IMPLIES UNEVENTFUL WEATHER WITH TEMPERATURES MODERATING TO CLOSER TO NORMAL VALUES. HOWEVER THERE ARE SIGNS THAT AN UPPER RIDGE WILL BEGIN TO BUILD OVER THE REGION ABOUT A WEEK FROM NOW AS A DEEP LONGWAVE TROUGH EVOLVES OVER THE WRN UNITED STATES. THIS IMPLIES THAT ABOVE NORMAL TEMPERATURES WILL DEVELOP BEYOND DAY 7. SFC HIGH PRESSURE WEDNESDAY AND THURSDAY OUGHT TO LEAD TO ABUNDANT SUNSHINE ALTHOUGH RATHER CHILLY NIGHTTIME TEMPERATURES. A WEAK SFC BOUNDARY DOES DROP SOUTH THROUGH THE REGION ON THURSDAY NIGHT BUT NO PRECIP IS EXPECTED AS THERE IS LITTLE MOISTURE TO WORK WITH. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 752 AM EDT SUN MAR 31 2013 IFR CONDITIONS HAVE SETTLED INTO WRN LWR MI BEHIND THE SFC FRONT WHICH AT 1130Z WAS ORIENTED NORTH-SOUTH ALONG ROUGHLY THE HIGHWAY 131 CORRIDOR. THE IFR CONDITIONS IN LOW CIGS AND MIST ARE EXPECTED TO LINGER THROUGH MID TO LATE MORNING BEFORE LIFTING AS SFC WINDS INCREASE OUT OF THE WEST AND BECOME GUSTY. PRIMARILY VFR IS EXPECTED AFTER 18Z AS THE MORNING STRATUS SHOULD HAVE TRANSITIONED INTO A CUMULUS DECK WITH HIGHER BASES. SOME ADDITIONAL ISOLATED RAIN SHOWERS MAY DEVELOP THIS AFTERNOON BUT LEFT THEM OUT OF THE TAFS SINCE VSBY RESTRICTIONS ARE UNLIKELY AND COVERAGE SHOULD BE LIMITED. && .MARINE... ISSUED AT 1000 AM EDT SUN MAR 31 2013 BASED ON LATEST 3KM HRRR GUIDANCE...SMALL CRAFT CONDITIONS WILL DEVELOP AROUND 00Z (8PM EDT) THIS EVENING...A BIT EARLIER THAN FIRST EXPECTED. WIND GUSTS AROUND 30 KTS WITH SEAS BUILDING 5 TO 7 FEET STILL LOOKING GOOD. VISIBILITY WILL OCCASIONALLY DROP BELOW 1 MILE IN LAKE EFFECT SNOW SHOWERS OVERNIGHT THROUGH MONDAY. HIGH PRESSURE WILL BRING FAIR WEATHER AND LIGHT WINDS FOR LATE TUESDAY THROUGH THURSDAY. && .HYDROLOGY... ISSUED AT 330 AM EDT SUN MAR 31 2013 NO HYDRO ISSUES EXPECTED. RIVERS ARE ALL WELL BELOW ACTION STAGE AND WILL REMAIN SO THROUGH THE WEEK. THE OVERALL WEATHER PATTERN THIS WEEK WILL BE CONDUCIVE TO A GRADUAL MELTING AND RUNOFF OF REMAINING SNOW COVER. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT TUESDAY FOR LMZ844>849. && $$ SYNOPSIS...LAURENS SHORT TERM...COBB LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...LAURENS MARINE...COBB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
746 AM EDT SUN MAR 31 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 544 AM EDT SUN MAR 31 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR TROF OVER CENTRAL NAMERICA DOWNSTREAM OF RDG OFF THE W COAST AS FAIRLY VIGOROUS SHRTWV NEAR LK WINNIPEG IS DIGGING SEWD TOWARD NW MN. SHRTWV RESPONSIBLE FOR PCPN ON SAT IS NOW OVER LOWER MI...AND ARRIVAL OF MUCH DRIER AIR SHOWN ON THE 00Z INL RAOB IS TENDING TO BREAK UP LINGERING FOG/LO CLD AT LEAST OVER THE WRN TIER DESPITE UPSLOPE LLVL WNW FLOW IN WAKE OF SFC LO PRES TROF ASSOCIATED WITH THAT DISTURBANCE. SINCE THE INCOMING AIRMASS WITH 00Z H85 TEMP OF -2C AT INL IS NOT SUFFICIENTLY COLD FOR LES EITHER...THERE IS NO PCPN. LOOKING UPSTREAM...AN AREA OF MID CLD IS PRESENT OVER NW MN/ NW ONTARIO AHEAD OF THE LK WINNIPEG SHRTWV AND ASSOCIATED COLD FNT PLUNGING SSEWD. PCPN AHEAD OF THIS BNDRY IS ABSENT GIVEN THE DRYNESS OF THE INL/YPL RAOBS DESPITE SOME RATHER SHARP DVPA/H85-5 QVECTOR CNVGC...BUT SOME PLACES SHOW SN IMMEDIATELY BEHIND THE FROPA. ALTHOUGH H85 TEMPS FALL SHARPLY BEHIND THE COLD FNT TO -14C AT THE PAS IN MANITOBA NEAR LK WINNIPEG...THE 00Z RAOB FM THAT SITE SHOWS A FAIRLY DRY AIRMASS/INVERTED V T-TD PROFILE BLO H85. BUT JUST TO THE E WITHIN THE COLDER AIRMASS...MORE CLDS/-SN ARE EVIDENT IN FAR NW ONTARIO. MAIN FCST CONCERNS THRU TNGT ARE SHSN POTENTIAL AND WINDS ASSOCIATED WITH AND FOLLOWING SHRTWV DIGGING TOWARD THE UPR GRT LKS/ATTENDANT COLD FROPA. EASTER SUN...AS LLVL DRY AIR MOVES IN EARLY THIS MRNG...EXPECT TREND TOWARD FOG/ST TO BREAK UP W-E. BUT ARRIVAL OF COLD FNT OVER THE NW BY LATE MRNG WL RESULT IN MORE CLDS AND SHSN IN THIS AREA AS AREA OF MSTR IN NW MN/ADJOINING ONTARIO SWINGS OVHD. SINCE THE MOST IMPRESSIVE DPVA/H85-5 QVECTOR CNVGC IS PROGGED TO SWING BY TO THE N OF UPR MI...EXPECT ACCOMPANYING SHSN TO BE RELATIVELY MODEST EVEN IF THERE IS SOME ENHANCEMENT OVER MAINLY THE HIER TERRAIN OF THE NW. AS THE FNT SWINGS THRU THE REST OF THE CWA EARLY THIS AFTN...DEEP LYR QVECTOR DVGC/MID LVL DRYING SHOULD LIMIT PCPN TO SCT -SHSN THAT WL BE AT LEAST MIXED WITH RA OVER THE SCNTRL AS TEMPS RISE AOA 40 IN THOSE DOWNSLOPE AREAS. BEST CHC FOR MORE NMRS SHSN WL BE OVER THE NRN TIER CLOSER TO SHRTWV DYNAMICS. EVEN WITH STRENGTHENING NW FLOW/CAD BEHIND THE FROPA THAT DROPS H85 TEMPS TO NEAR -14C BY 00Z MON...ARRIVAL OF DRIER AIR MORE REPRESENTED BY THE 00Z YQD RAOB ALONG WITH DAYTIME HEATING/INVERTED V LOOK TO GFS FCST SDNGS FOR CMX SHOULD TEND TO LIMIT THE SHSN INTENSITY IN THE WAKE OF THE FROPA. AS FOR THE WINDS...THE PREFERRED GFS SHOWS A FAIRLY SHARP PRES RISE CENTER FOLLOWING THE FROPA AND REACHING NCENTRL LK SUP BY 00Z WITH ISALLOBARIC WIND FAVORABLY ALIGNED WITH THE NW GRADIENT FLOW. SINCE SEVERAL MODELS SHOW H925 WINDS UP TO 40 KTS STREAMING INTO THE ERN ZNS AT 00Z WITH CONSIDERABLE CAD/DESTABILIZATION AS WELL AS THE FAVORABLE ALIGNMENT OF THE ISALLOBARIC WIND TO THE GRADIENT FLOW... EXPECT ADVY LVL GUSTS TO 45 MPH IN THE EXPOSED LK SUP SHORELINE E OF MQT AFT 21Z. AS THE CLOSED LO OVER SE CANADA MOVES TO THE E TNGT...SHARP CYC NW FLOW IS PROGGED TO VEER A BIT MORE TOWARD THE NNW...WHICH MIGHT ALLOW DEEPER MSTR NOW OVER NW ONTARIO TO INFILTRATE THE UPR LKS AS SHOWN BY NMRS MODEL H7 RH PROGS. IN COMBINATION WITH H85 TEMPS FALLING AS LO AS -17C TO -18C AND NOCTURNAL COOLING THAT WOULD FAVOR MORE TYPICAL LES BANDING...MAINTAINED THE FLAVOR OF PREVIOUS FCST WITH LES POPS INCRSG TO CATEGORICAL IN THE SN BELTS FAVORED BY THE EXPECTED FLOW. NEARLY UNIDIRECTIONAL NATURE OF THE SFC-H85 FLOW IN THE WELL MIXED CONVECTIVE LYR MIGHT ALSO FAVOR HEAVIER SN BANDS. SINCE THE ERN ZNS WL BE CLOSER TO THE DEPARTING LO...HAVE A BETTER OPPORTUNITY TO BE IMPACTED BY THE DEEPER MSTR...AND WL SEE ADVY LVL WIND GUSTS AT LEAST THRU 06Z BEFORE THE PRES RISE CENTER SHIFTS FARTHER E AND WEAKENS THE ISALLOBARIC WIND...OPTED TO ISSUE A WINTER WX ADVY FOR ALGER/NRN SCHOOLCRAFT/LUCE COUNTIES FOR THE COMBINATION OF STRONG WINDS...LES...AND BLSN. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 544 AM EDT SUN MAR 31 2013 AFTER A SEVERAL DAY STRETCH OF NEAR NORMAL EARLY SPRING WEATHER...IT LOOKS LIKE A RETURN TO FEBRUARY LIKE WEATHER IS ON TAP FOR THE EARLY PART OF THE WORK WEEK. COLD ADVECTION WILL CONTINUE ON MONDAY ON THE BACKSIDE OF UPPER TROUGH PUSHING THROUGH THE UPPER LAKES. 85H TEMPS FALL DOWN TO AROUND -18C ACROSS LAKE SUPERIOR DURING THE DAY ON MONDAY. UNUSUAL TO BE DEALING WITH LAKE EFFECT IN EARLY APRIL BUT WITH LAKE TEMPS BETWEEN 1-2C...SUFFICIENT DELTA TS WILL BE IN PLACE FOR LAKE EFFECT SNOW IN NORTHWESTERLY WIND SNOW BELTS. THE CHALLENGE OF THE FCST IS THE EXTENT OF ACCUMULATIONS AND OVERALL IMPACTS OF THE SNOW. THE FACT THAT IT IS APRIL...FCST SOUNDINGS ARE SHOWING A LOW LEVEL INVERTED V SIGNATURE...THE TYPICAL DISRUPTION IN THE LAKE EFFECT PROCESS FROM DIURNAL HEATING THIS TIME OF YEAR...ALL LEND TO THE UNCERTAINTY IN THE FCST. AREAS MOSTLY LIKELY TO SEE MORE OF THE IMPACTS WILL BE ALGER AND LUCE COUNTIES AND WILL LET WINTER WEATHER ADVISORY EXTEND THROUGH MONDAY MORNING TO ACCOUNT FOR FALLING SNOW AND BLOWING SNOW...ESPECIALLY NEAR LAKE SUPERIOR. THE NEGATIVES LISTED ABOVE MAY THEN BECOME TOO MUCH FOR SIGNIFICANT IMPACTS DURING THE AFTERNOON MONDAY. AWAY FROM THIS AREA...EXPECT LAKE EFFECT SNOW SNOW SHOWERS TO PRODUCE SOME LIGHT ACCUMULATIONS ACROSS THE KEWEENAW AND WESTERN U.P. THE MOST NOTICEABLE THING ABOUT MONDAY WILL BE THE FACT THAT TEMPERATURES WILL ONLY CLIMB INTO THE LOWER TO MID 20S AND WITH GUSTY NORTHWEST WINDS IT WILL FEEL CONSIDERABLY COLDER. THERE COULD BE A SLIGHT UPTICK IN LAKE EFFECT SNOW MONDAY NIGHT ACROSS THE EAST WITH INVERSION HEIGHTS REMAINING AROUND 8KFT...TRAJECTORIES FAVORING A LITTLE MORE LOW LEVEL MOISTURE...AND TYPICAL NIGHTTIME INCREASE IN LAKE EFFECT THIS TIME OF YEAR. MAY NEED TO CONSIDER ANOTHER ADVISORY FOR ALGER AND LUCE COUNTIES AGAIN MONDAY NIGHT. ELSEWHERE...EXPECT LAKE EFFECT SNOW SHOWERS TO CONTINUE ACROSS THE WEST BUT ACCUMULATIONS SHOULD REMAIN RELATIVELY LIGHT. LAKE EFFECT PROCESS WINDS DOWN QUICKLY ON TUESDAY WITH INVERSION LOWERING SIGNIFICANTLY AND SURFACE RIDGING APPROACHING FROM THE WEST. TEMPERATURES WILL REMAIN WELL BELOW NORMAL...MORE LIKE MID FEBRUARY. RIDGE AXIS WILL MOVE ACROSS THE AREAM ON WEDNESDAY. WITH ABUNDANT SUNSHINE AND WARM ADVECTION COMMENCING ON THE BACK SIDE OF THE RIDGE TEMPS SHOULD REBOUND BACK ABOVE FREEZING TO WITHIN A FEW DEGREES OF NORMAL. NEXT TROUGH AND FRONT WILL CROSS THE AREA ON THURSDAY. NOT VERY MUCH MOISTURE TO WORK WITH SO ONLY EXPECT SOME LIGHT RAIN AND SNOW SHOWERS WITH ITS PASSAGE. ANOTHER DECENT COLD SHOT WILL KNOCK TEMPERATURES BACK BELOW NORMAL FOR FRIDAY. HAVENT LOOKED TOO MUCH AT NEXT WEEKENDS FORECAST BUT THERE APPEARS TO BE A TREND POINTING TOWARD A MORE SOUTHERN TRACK OF A STORM SYSTEM PUSHING THROUGH THE LOWER LAKES. WILL BE SOMETHING TO KEEP AN EYE ON AS THE WEEK PROGRESSES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 746 AM EDT SUN MAR 31 2013 WITH DRY AIR SHOWN ON THE 00Z INL RAOB DOMINATING EARLY IN THE FCST PERIOD...VFR CONDITIONS WL PREDOMINATE. THE ARRIVAL OF A SHARP COLD FNT OVER THE W BY LATE MRNG WL CAUSE SOME SHSN AND CONDITIONS TO DETERIORATE TO MVFR AT CMX/IWD. THE BEST CHC FOR SOME HEAVIER SHSN AND IFR CONDITIONS WL BE AT CMX...CLOSER TO THE INCOMING DISTURBANCE AND WHERE NW FLOW WL UPSLOPE. GUSTY NW WINDS WL REACH AOA 30 KTS AT THE MORE EXPOSED CMX LOCATION IN THE WAKE OF THE COLD FROPA THIS AFTN. DOWNSLOPE NATURE OF THE FLOW AND GREATER DAYTIME HEATING/ MIXING INDICATES VFR CONDITIONS WL PREDOMINATE AT SAW MOST OF THE DAY. WITH NOCTURNAL COOLING AND THE ARRIVAL OF SOME DEEPER MSTR... EXPECT MVFR CONDITIONS WITH SOME SHSN TNGT AT ALL 3 SITES AS THE GUSTY NW WINDS DRAW COLDER AIR INTO THE UPR LKS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 544 AM EDT SUN MAR 31 2013 AS A STRONG DISTURBANCE MOVES OVER LK SUP TODAY...A DEEP LO PRES WILL TAKE SHAPE OVER SE CANADA AND CAUSE NW WIND TO INCREASE TO GALE FORCE OVER THE NCENTRAL AND E PORTIONS OF THE LAKE BY THIS AFTERNOON. THESE STRONG NW WINDS WILL CONTINUE TONIGHT AND DRAW MUCH COLDER AIR INTO THE UPPER LAKES. THE RESULT WILL BE FREEZING SPRAY. MAINTAINED GOING GALE WARNING FOR MOST OF THE NCENTRAL AND E HALF. NORTHWEST GALES WILL CONTINUE ACROSS THE EASTERN HALF OF LAKE SUPERIOR INTO TUESDAY BEFORE RIDGING BUILDS ACROSS THE LAKE WITH WINDS DIMINISHING TO LESS THAN 20 KNOTS. WINDS SHOULD REMAIN BELOW 20 KNOTS INTO THURSDAY BEFORE THE NEXT QUICK MOVING FRONT MOVES ACROSS THE UPPER GREAT LAKES. NORTHWEST WINDS TO 30 KNOTS WILL BE POSSIBLE BEHIND THE FRONT TO END THE WORK WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT MONDAY FOR MIZ006-007-085. LAKE SUPERIOR... GALE WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT TUESDAY FOR LSZ264>267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 PM EDT MONDAY FOR LSZ244-245-249>251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...MZ AVIATION...KC MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
544 AM EDT SUN MAR 31 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 544 AM EDT SUN MAR 31 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR TROF OVER CENTRAL NAMERICA DOWNSTREAM OF RDG OFF THE W COAST AS FAIRLY VIGOROUS SHRTWV NEAR LK WINNIPEG IS DIGGING SEWD TOWARD NW MN. SHRTWV RESPONSIBLE FOR PCPN ON SAT IS NOW OVER LOWER MI...AND ARRIVAL OF MUCH DRIER AIR SHOWN ON THE 00Z INL RAOB IS TENDING TO BREAK UP LINGERING FOG/LO CLD AT LEAST OVER THE WRN TIER DESPITE UPSLOPE LLVL WNW FLOW IN WAKE OF SFC LO PRES TROF ASSOCIATED WITH THAT DISTURBANCE. SINCE THE INCOMING AIRMASS WITH 00Z H85 TEMP OF -2C AT INL IS NOT SUFFICIENTLY COLD FOR LES EITHER...THERE IS NO PCPN. LOOKING UPSTREAM...AN AREA OF MID CLD IS PRESENT OVER NW MN/ NW ONTARIO AHEAD OF THE LK WINNIPEG SHRTWV AND ASSOCIATED COLD FNT PLUNGING SSEWD. PCPN AHEAD OF THIS BNDRY IS ABSENT GIVEN THE DRYNESS OF THE INL/YPL RAOBS DESPITE SOME RATHER SHARP DVPA/H85-5 QVECTOR CNVGC...BUT SOME PLACES SHOW SN IMMEDIATELY BEHIND THE FROPA. ALTHOUGH H85 TEMPS FALL SHARPLY BEHIND THE COLD FNT TO -14C AT THE PAS IN MANITOBA NEAR LK WINNIPEG...THE 00Z RAOB FM THAT SITE SHOWS A FAIRLY DRY AIRMASS/INVERTED V T-TD PROFILE BLO H85. BUT JUST TO THE E WITHIN THE COLDER AIRMASS...MORE CLDS/-SN ARE EVIDENT IN FAR NW ONTARIO. MAIN FCST CONCERNS THRU TNGT ARE SHSN POTENTIAL AND WINDS ASSOCIATED WITH AND FOLLOWING SHRTWV DIGGING TOWARD THE UPR GRT LKS/ATTENDANT COLD FROPA. EASTER SUN...AS LLVL DRY AIR MOVES IN EARLY THIS MRNG...EXPECT TREND TOWARD FOG/ST TO BREAK UP W-E. BUT ARRIVAL OF COLD FNT OVER THE NW BY LATE MRNG WL RESULT IN MORE CLDS AND SHSN IN THIS AREA AS AREA OF MSTR IN NW MN/ADJOINING ONTARIO SWINGS OVHD. SINCE THE MOST IMPRESSIVE DPVA/H85-5 QVECTOR CNVGC IS PROGGED TO SWING BY TO THE N OF UPR MI...EXPECT ACCOMPANYING SHSN TO BE RELATIVELY MODEST EVEN IF THERE IS SOME ENHANCEMENT OVER MAINLY THE HIER TERRAIN OF THE NW. AS THE FNT SWINGS THRU THE REST OF THE CWA EARLY THIS AFTN...DEEP LYR QVECTOR DVGC/MID LVL DRYING SHOULD LIMIT PCPN TO SCT -SHSN THAT WL BE AT LEAST MIXED WITH RA OVER THE SCNTRL AS TEMPS RISE AOA 40 IN THOSE DOWNSLOPE AREAS. BEST CHC FOR MORE NMRS SHSN WL BE OVER THE NRN TIER CLOSER TO SHRTWV DYNAMICS. EVEN WITH STRENGTHENING NW FLOW/CAD BEHIND THE FROPA THAT DROPS H85 TEMPS TO NEAR -14C BY 00Z MON...ARRIVAL OF DRIER AIR MORE REPRESENTED BY THE 00Z YQD RAOB ALONG WITH DAYTIME HEATING/INVERTED V LOOK TO GFS FCST SDNGS FOR CMX SHOULD TEND TO LIMIT THE SHSN INTENSITY IN THE WAKE OF THE FROPA. AS FOR THE WINDS...THE PREFERRED GFS SHOWS A FAIRLY SHARP PRES RISE CENTER FOLLOWING THE FROPA AND REACHING NCENTRL LK SUP BY 00Z WITH ISALLOBARIC WIND FAVORABLY ALIGNED WITH THE NW GRADIENT FLOW. SINCE SEVERAL MODELS SHOW H925 WINDS UP TO 40 KTS STREAMING INTO THE ERN ZNS AT 00Z WITH CONSIDERABLE CAD/DESTABILIZATION AS WELL AS THE FAVORABLE ALIGNMENT OF THE ISALLOBARIC WIND TO THE GRADIENT FLOW... EXPECT ADVY LVL GUSTS TO 45 MPH IN THE EXPOSED LK SUP SHORELINE E OF MQT AFT 21Z. AS THE CLOSED LO OVER SE CANADA MOVES TO THE E TNGT...SHARP CYC NW FLOW IS PROGGED TO VEER A BIT MORE TOWARD THE NNW...WHICH MIGHT ALLOW DEEPER MSTR NOW OVER NW ONTARIO TO INFILTRATE THE UPR LKS AS SHOWN BY NMRS MODEL H7 RH PROGS. IN COMBINATION WITH H85 TEMPS FALLING AS LO AS -17C TO -18C AND NOCTURNAL COOLING THAT WOULD FAVOR MORE TYPICAL LES BANDING...MAINTAINED THE FLAVOR OF PREVIOUS FCST WITH LES POPS INCRSG TO CATEGORICAL IN THE SN BELTS FAVORED BY THE EXPECTED FLOW. NEARLY UNIDIRECTIONAL NATURE OF THE SFC-H85 FLOW IN THE WELL MIXED CONVECTIVE LYR MIGHT ALSO FAVOR HEAVIER SN BANDS. SINCE THE ERN ZNS WL BE CLOSER TO THE DEPARTING LO...HAVE A BETTER OPPORTUNITY TO BE IMPACTED BY THE DEEPER MSTR...AND WL SEE ADVY LVL WIND GUSTS AT LEAST THRU 06Z BEFORE THE PRES RISE CENTER SHIFTS FARTHER E AND WEAKENS THE ISALLOBARIC WIND...OPTED TO ISSUE A WINTER WX ADVY FOR ALGER/NRN SCHOOLCRAFT/LUCE COUNTIES FOR THE COMBINATION OF STRONG WINDS...LES...AND BLSN. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 544 AM EDT SUN MAR 31 2013 AFTER A SEVERAL DAY STRETCH OF NEAR NORMAL EARLY SPRING WEATHER...IT LOOKS LIKE A RETURN TO FEBRUARY LIKE WEATHER IS ON TAP FOR THE EARLY PART OF THE WORK WEEK. COLD ADVECTION WILL CONTINUE ON MONDAY ON THE BACKSIDE OF UPPER TROUGH PUSHING THROUGH THE UPPER LAKES. 85H TEMPS FALL DOWN TO AROUND -18C ACROSS LAKE SUPERIOR DURING THE DAY ON MONDAY. UNUSUAL TO BE DEALING WITH LAKE EFFECT IN EARLY APRIL BUT WITH LAKE TEMPS BETWEEN 1-2C...SUFFICIENT DELTA TS WILL BE IN PLACE FOR LAKE EFFECT SNOW IN NORTHWESTERLY WIND SNOW BELTS. THE CHALLENGE OF THE FCST IS THE EXTENT OF ACCUMULATIONS AND OVERALL IMPACTS OF THE SNOW. THE FACT THAT IT IS APRIL...FCST SOUNDINGS ARE SHOWING A LOW LEVEL INVERTED V SIGNATURE...THE TYPICAL DISRUPTION IN THE LAKE EFFECT PROCESS FROM DIURNAL HEATING THIS TIME OF YEAR...ALL LEND TO THE UNCERTAINTY IN THE FCST. AREAS MOSTLY LIKELY TO SEE MORE OF THE IMPACTS WILL BE ALGER AND LUCE COUNTIES AND WILL LET WINTER WEATHER ADVISORY EXTEND THROUGH MONDAY MORNING TO ACCOUNT FOR FALLING SNOW AND BLOWING SNOW...ESPECIALLY NEAR LAKE SUPERIOR. THE NEGATIVES LISTED ABOVE MAY THEN BECOME TOO MUCH FOR SIGNIFICANT IMPACTS DURING THE AFTERNOON MONDAY. AWAY FROM THIS AREA...EXPECT LAKE EFFECT SNOW SNOW SHOWERS TO PRODUCE SOME LIGHT ACCUMULATIONS ACROSS THE KEWEENAW AND WESTERN U.P. THE MOST NOTICEABLE THING ABOUT MONDAY WILL BE THE FACT THAT TEMPERATURES WILL ONLY CLIMB INTO THE LOWER TO MID 20S AND WITH GUSTY NORTHWEST WINDS IT WILL FEEL CONSIDERABLY COLDER. THERE COULD BE A SLIGHT UPTICK IN LAKE EFFECT SNOW MONDAY NIGHT ACROSS THE EAST WITH INVERSION HEIGHTS REMAINING AROUND 8KFT...TRAJECTORIES FAVORING A LITTLE MORE LOW LEVEL MOISTURE...AND TYPICAL NIGHTTIME INCREASE IN LAKE EFFECT THIS TIME OF YEAR. MAY NEED TO CONSIDER ANOTHER ADVISORY FOR ALGER AND LUCE COUNTIES AGAIN MONDAY NIGHT. ELSEWHERE...EXPECT LAKE EFFECT SNOW SHOWERS TO CONTINUE ACROSS THE WEST BUT ACCUMULATIONS SHOULD REMAIN RELATIVELY LIGHT. LAKE EFFECT PROCESS WINDS DOWN QUICKLY ON TUESDAY WITH INVERSION LOWERING SIGNIFICANTLY AND SURFACE RIDGING APPROACHING FROM THE WEST. TEMPERATURES WILL REMAIN WELL BELOW NORMAL...MORE LIKE MID FEBRUARY. RIDGE AXIS WILL MOVE ACROSS THE AREAM ON WEDNESDAY. WITH ABUNDANT SUNSHINE AND WARM ADVECTION COMMENCING ON THE BACK SIDE OF THE RIDGE TEMPS SHOULD REBOUND BACK ABOVE FREEZING TO WITHIN A FEW DEGREES OF NORMAL. NEXT TROUGH AND FRONT WILL CROSS THE AREA ON THURSDAY. NOT VERY MUCH MOISTURE TO WORK WITH SO ONLY EXPECT SOME LIGHT RAIN AND SNOW SHOWERS WITH ITS PASSAGE. ANOTHER DECENT COLD SHOT WILL KNOCK TEMPERATURES BACK BELOW NORMAL FOR FRIDAY. HAVENT LOOKED TOO MUCH AT NEXT WEEKENDS FORECAST BUT THERE APPEARS TO BE A TREND POINTING TOWARD A MORE SOUTHERN TRACK OF A STORM SYSTEM PUSHING THROUGH THE LOWER LAKES. WILL BE SOMETHING TO KEEP AN EYE ON AS THE WEEK PROGRESSES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 134 AM EDT SUN MAR 31 2013 ARRIVAL OF DRIER AIR SHOWN ON THE 00Z INL RAOB WILL RESULT IN VFR CONDITIONS EARLY THIS MRNG AT CMX/IWD AND A BREAKUP OF THE FOG/ST/IFR CONDITIONS NOW IMPACTING SAW BY 09Z. EXPECT INCREASING POTENTIAL OF -SHSN AT WRN TAF SITES BY LATE MRNG AS CONDITIONS FALL TO MVFR AT CMX/IWD WITH ARRIVAL OF NEXT DISTURBANCE. GUSTY WNW WINDS WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE LATE THIS MORNING. WNW AND COLD ADVECTION BEHIND FRONT WILL BRING A CHANCE OF -SHSN SUNDAY AFTERNOON AT KSAW ALONG WITH MVFR CIGS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 544 AM EDT SUN MAR 31 2013 AS A STRONG DISTURBANCE MOVES OVER LK SUP TODAY...A DEEP LO PRES WILL TAKE SHAPE OVER SE CANADA AND CAUSE NW WIND TO INCREASE TO GALE FORCE OVER THE NCENTRAL AND E PORTIONS OF THE LAKE BY THIS AFTERNOON. THESE STRONG NW WINDS WILL CONTINUE TONIGHT AND DRAW MUCH COLDER AIR INTO THE UPPER LAKES. THE RESULT WILL BE FREEZING SPRAY. MAINTAINED GOING GALE WARNING FOR MOST OF THE NCENTRAL AND E HALF. NORTHWEST GALES WILL CONTINUE ACROSS THE EASTERN HALF OF LAKE SUPERIOR INTO TUESDAY BEFORE RIDGING BUILDS ACROSS THE LAKE WITH WINDS DIMINISHING TO LESS THAN 20 KNOTS. WINDS SHOULD REMAIN BELOW 20 KNOTS INTO THURSDAY BEFORE THE NEXT QUICK MOVING FRONT MOVES ACROSS THE UPPER GREAT LAKES. NORTHWEST WINDS TO 30 KNOTS WILL BE POSSIBLE BEHIND THE FRONT TO END THE WORK WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT MONDAY FOR MIZ006-007-085. LAKE SUPERIOR... GALE WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT TUESDAY FOR LSZ264>267. GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 PM EDT MONDAY FOR LSZ244-245-249>251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...MZ AVIATION...KC MARINE...KC/MZ
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
659 AM CDT SUN MAR 31 2013 .SHORT TERM...(EASTER SUNDAY) ISSUED AT 224 AM CDT SUN MAR 31 2013 FORECAST HAS CHANGED TODAY GIVEN CURRENT CONDITIONS AND LATEST SHORT RANGE MODEL GUIDANCE. SHORTWAVE ENERGY...EVIDENT ON LATEST WATER VAPOR IMAGERY...DROPPING SOUTHEAST FROM SOUTHERN NEBRASKA HAS LED TO A LARGE AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOPING ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI. LATEST RUC AND HRRR SHOW THIS AREA OF RAIN SHOWERS/STORMS EXPANDING AS EAST/SOUTHEAST THIS MORNING ACROSS CENTRAL MISSOURI AND THE OZARKS...PERHAPS GRAZING EAST CENTRAL MISSOURI AND SOUTHWEST ILLINOIS. WILL FINE TUNE POPS BEFORE FORECAST ISSUANCE BASED ON THE VERY LATEST RADAR TRENDS. THERE WILL OBVIOUSLY BE A SLOWER CLEARING TREND TO THE CLOUDS THANKS TO THIS SHORTWAVE...AND FEEL IT PRUDENT TO SIDE WITH SLIGHTLY COOLER MAV GUIDANCE FOR HIGH TEMPERATURES. TO COMPLICATE THE FORECAST EVEN FURTHER...MUCH OF THE EXPLICIT AND HIGH RESOLUTION MODEL GUIDANCE DEPICT SOME ISOLATED SHOWERS DEVELOPING ALONG A PREFRONTAL TROF THIS AFTERNOON AND EVENING FROM CENTRAL ILLINOIS TOWARD THE ST. LOUIS METRO AREA. SO HAVE INCLUDED SOME LOW CHANCE/ISOLATED POPS FOR THIS AS WELL. CVKING && .LONG TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 224 AM CDT SUN MAR 31 2013 (TONIGHT AND MONDAY) ARCTIC COLD FRONT EXPECTED TO MOVE SOUTH ACROSS THE CWA TONIGHT WITH NORTH WIND AND COLD ADVECTION TAKING CONTROL OF THE WEATHER FOR THE EARLY PART OF THE WORK WEEK. LATEST GUIDANCE CONTINUES TO DEPICT A BAND OF LIGHT POST FRONTAL PRECIPITATION AFFECTING MAINLY NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS SUNDAY NIGHT. THIS PRECIPITATION SHOULD WEAKEN AS IT PROGRESSES SOUTH MONDAY MORNING TO THE I-70 CORRIDOR. MAINTAINED RAIN/SNOW MIX...BUT DONT EXPECT ANY ACCUMULATION DUE TO WARM AIR AND GROUND TEMPERATURES. HAVE SIDED WITH COOLER MET GUIDANCE FOR TEMPERATURES. (TUESDAY THROUGH SATURDAY) SLOW WARMING TREND EXPECTED WITH HIGH PRESSURE MOVING EAST OF THE AREA BY LATE IN THE WEEK. HAVE KEPT FORECAST DRY AS GUIDANCE KEEPS CUTOFF LOW TO THE SOUTH OF THE AREA THURSDAY. CVKING && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 640 AM CDT SUN MAR 31 2013 IFR CIGS/VSBYS WILL CONTINUE TO BE POSSIBLE ACROSS MUCH OF CENTRAL AND NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS UNTIL 14-15Z. ANOTHER AREA OF IFR OVER SOUTHWEST AND SOUTH CENTRAL ILLINOIS WILL LIKELY PERSIST UNTIL 15Z AS WELL. AFTER THAT...EXPECT VFR FLIGHT CONDITIONS TO PREVAIL TODAY AHEAD OF A STRONG COLD FRONT. WILL LIKELY ALSO SEE SOME GUSTY WEST-NORTHWEST WINDS OF UP TO AROUND 25KTS TODAY AHEAD OF THE FRONT. WILL EXPECT TO SEE WINDS DROP OFF AROUND 00Z. COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING...SHIFTING THE WIND TO THE NORTH. THERE MAY BE SOME LIGHT RAIN OR LIGHT SNOW NORTH OF I-70 TONIGHT SPECIFICS FOR KSTL... EXPECT MVFR FLIGHT CONDITIONS TO PREVAIL FOR A FEW MORE HOURS THIS MORNING AT LAMBERT BEFORE RISING TO VFR BETWEEN 14-15Z. THERE IS A CHANCE THAT CIGS OR VSBYS COULD DROP BACK BRIEFLY INTO IFR RANGE...BUT THE CHANCE OF THAT HAPPENING IS RAPIDLY DIMINISHING WITH SUNRISE AND DRIER AIR MOVING IN FROM THE NORTHWEST. WIND WILL PICK UP BY EARLY THIS AFTERNOON AND WE COULD SEE GUSTS TO AROUND 25KTS. WIND SHOULD DIMINISH BY AROUND 00Z. COLD FRONT WILL MOVE THROUGH THE TERMINAL AROUND 06Z TONIGHT WHICH WILL SHIFT THE WIND TO THE NORTH. CURRENT INDICATIONS ARE THAT THE FRONT WILL GO THROUGH DRY AND CEILINGS WILL STAY ABOVE 5000FT UNTIL AROUND 12Z MONDAY MORNING. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
734 AM EDT SUN MAR 31 2013 .SYNOPSIS... SOUTHERLY WINDS WILL BRING A MILD DAY TODAY BEFORE A COLD FRONT APPROACHES WITH SHOWERS DEVELOPING DURING THE AFTERNOON. THE COLD FRONT WILL USHER IN MUCH COLDER TEMPERATURES FOR THE FIRST HALF OF NEXT WEEK ALONG WITH SCATTERED SNOW SHOWERS AND HEAVIER LAKE EFFECT SNOW EAST OF THE LAKES. && .NEAR TERM /THROUGH TONIGHT/... LEAD SHORTWAVE CURRENTLY LIFTING INTO THE OHIO VALLEY. ASSOCIATED SHOWER ACTIVITY SHOWING UP ON UPSTREAM REGIONAL RADARS ACROSS WESTERN OHIO. THIS ACTIVITY IS IN DECENT AGREEMENT WITH LATEST HIGHER RESOLUTION HRRR RUN WHICH BRINGS THE LEADING EDGE OF SHOWERS ASSOCIATED WITH THIS SHORTWAVE INTO THE SOUTHERN TIER AND WESTERN FINGER LAKES BETWEEN 10 AM AND 2 PM. MODELS CONTINUING TO AGREE UPON THE SPLIT IN PRECIPITATION PATTERN BETWEEN THE SOUTHERN AREA OF PRECIPITATION ASSOCIATED WITH THE SHORTWAVE WORKING THROUGH THE OHIO VALLEY... AND THE NORTHERN STREAM SYSTEM WHICH LAGS BEHIND BY SEVERAL HOURS. THE NORTHERN SYSTEM WILL GENERATE ADDITIONAL WIDESPREAD SHOWER ACTIVITY BY EARLY TO MID AFTERNOON AS THE ASSOCIATED COLD FRONT APPROACHES THE REGION. SPC SREF PARAMETERS KEEP PRIMARY INSTABILITY AXIS WELL SOUTH OF THE AREA...THEREFORE NO NEED TO INCLUDE MENTION OF THUNDER IN THE FORECAST. AHEAD OF THE FRONT AND BEFORE THE RAIN ARRIVES...THE SOUTHERLY DOWNSLOPE FLOW COMBINED WITH WARMER TEMPERATURES ALOFT WILL ALLOW THE LAKE PLAINS TO WARM WELL INTO THE 50S. THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER AND EAST OF LAKE ONTARIO WILL TOP OUT IN THE MID TO UPPER 40S WITHOUT THE BENEFIT OF DOWNSLOPE FLOW AND AN EARLIER START TO THE RAIN. THE COLD FRONT WILL BE PUSH THROUGH EARLY TONIGHT. THE COLD AIR ADVECTION IS QUITE IMPRESSIVE BEHIND THE FRONT AND WE SHOULD SEE A CHANGE OVER TO SNOW OR A MIX BRIEFLY BEFORE THE PRECIPITATION DIMINISHES OVERNIGHT. WIND SHOULD PICK UP IN THE STRONG COLD AIR ADVECTIVE PATTERN...BUT SHOULD BE LIMITED TO GUSTS TO NEAR 30 MPH. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AN ARCTIC FRONT WILL CROSS THE REGION MONDAY MORNING WITH A CHANGEOVER FROM RAIN TO SNOW SHOWERS. 850MB TEMPS AT 12Z MONDAY WILL RANGE -12C AT THE NIAGARA RIVER TO -4C ACROSS CENTRAL NY...FALLING TO -12C TO -13C BY 00Z TUESDAY. THESE BOUNDARY LAYER TEMPS WILL BE SUFFICIENTLY COLD TO SUPPORT SOME LAKE EFFECT RESPONSE...BUT THE DESTABILIZING EFFECT OF EARLY APRIL SUNSHINE WILL DISRUPT ANY CONCENTRATED PRECIP...WILL HAVE LIKELY POPS FOR SMALL ACCUMULATIONS BUT DO NOT EXPECT ANY SIGNIFICANT ACCUMS UNTIL OVERNIGHT MONDAY NIGHT TO TUESDAY MORNING. WELL ALIGNED WESTERLY WINDS WILL FOCUS THE LAKE SNOW ON THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER AND ON THE TOP OF THE TUG HILL PLATEAU EAST OF LAKE ONTARIO. THE LONGER FETCH ALONG THE LENGTH OF LAKE ONTARIO WILL ALLOW THE TUG HILL TO APPRECIATE A BETTER CHANCE FOR SIGNIFICANT SNOW ACCUMULATION MONDAY NIGHT THROUGH EARLY WEDNESDAY. BOTH 00Z GFS AND ECMWF SHOW A WEAK SHORT WAVE CROSSING THE EASTERN GREAT LAKES ON WEDNESDAY WITH ONLY CHANCE POPS ASSOCIATED...LIMITING FACTORS AS THE LACK OF DEEP MOISTURE AND SURFACE HIGH PRESSURE STARTING TO BUILD IN FROM THE WEST. IT IS POSSIBLE THAT THIS LAKE EFFECT EVENT FROM MONDAY NIGHT TO WEDNESDAY MORNING MAY BRING WARNING CRITERIA SNOWS AS SUGGESTED BY RECENT CIPS ANALOGS OF THE TOP 15 MOST SIMILAR EVENTS. ACCUMULATIONS OF 6 TO 12 INCHES OR MORE MAY BE POSSIBLE UNDER THE MOST PERSISTENT BANDS. THE DURATION OF THE EVENT WILL LIKELY LEAD TO THE HIGHER ACCUMULATIONS...EVEN WITH THE LIMITING FACTOR OF LESS THAN OPTIMAL MOISTURE PROFILE AND THE DISRUPTIVE INSOLATION EFFECTS DURING THE DAYTIME. WILL CONTINUE TO HIGHLIGHT THIS EVENT IN THE HWO...BUT WILL HOLD OFF FOR ANOTHER MODEL RUN TO ASSESS THE POSSIBILITY OF A LAKE SNOW WATCH. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH MONDAY AND TUESDAY. THE COLD AIR ADVECTION WILL KEEP HIGHS LIMITED TO THE LOW AND MID 30S...AND ONLY UPPER 20S OVER THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER AND TUG HILL ON TUESDAY. OVERNIGHT LOWS WILL BE IN THE 20S MONDAY AND TUESDAY NIGHTS. WEDNESDAY WILL HAVE A SLIGHT RISE IN TEMPS WITH HIGHS IN THE 30S ACROSS THE REGION AND BACK TO 20S WEDNESDAY NIGHT. && .LONG TERM /THURSDAY THROUGH SATURDAY/... NOW HERE IS THE GOOD NEWS...WE BEGIN TO SEE TEMPERATURES MODERATING BACK TO NORMAL THROUGH NEXT WEEKEND. WE WILL SEE SOME BRIEF RIDGING ON THURSDAY BRINGING A SUNNY DAY WITH WARMER TEMPS RISING INTO THE UPPER 40S. SIMILAR CONDITIONS TO WHAT WE SAW THIS FINE SATURDAY AFTERNOON. THE FORECAST BECOMES A BIT DIFFICULT ON FRIDAY WHERE BOTH GFS AND EC MODELS PHASE THE TWO SHORTWAVES TOGETHER ALONG THE EAST COAST WITH DEEP SURFACE CYCLOGENESIS OCCURRING. THERE ARE SOME DIFFERENCES IN TIMING AND LOCATION OF THE FORMATION OF A STRONG SURFACE LOW BUT GENERALLY THE MODELS LIFT IT FROM THE CAROLINA COAST NORTH TOWARD NEW ENGLAND BY FRIDAY NIGHT. ANOTHER WEAKER SYSTEM WILL DRIFT ACROSS EASTERN CANADA. THERE IS POTENTIAL FOR EITHER SYSTEM TO CLIP OUR FORECAST AREA SO WILL GO WITH LOW CHANGE FOR SHOWERS AT THIS TIME. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS THIS MORNING WILL DETERIORATE TO MVFR IN AREAS OF RAIN SHOWERS DURING THE MID TO LATE AFTERNOON...WITH IFR POSSIBLE ACROSS THE HIGHER TERRAIN. S-SW SURFACE WINDS WILL INCREASE TO 15-25 KTS LATER THIS MORNING AND AFTERNOON. A FRONTAL BOUNDARY WILL CROSS THIS EVENING WITH WINDS SHIFTING TO THE SOUTHWEST BETWEEN 21Z-03Z...THEN TO THE WEST BETWEEN 06Z AND 12Z. OUTLOOK... MONDAY...VFR/MVFR WITH A FEW SNOW SHOWERS LIKELY. MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS...EXCEPT IFR IN LAKE EFFECT SNOW EAST OF THE LAKES. WEDNESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS. THURSDAY...VFR. && .MARINE... SOUTHERLY WINDS WILL INCREASE TODAY AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL SWEEP ACROSS THE LOWER LAKES TONIGHT. FOLLOWING THE FRONT MODERATE TO STRONG WESTERLIES WILL BRING AN EXTENDED PERIOD OF SMALL CRAFT CONDITIONS TO BOTH LAKES THROUGH MIDWEEK. WINDS MAY GET CLOSE TO GALE FORCE AT TIMES MONDAY AND TUESDAY ON LAKE ONTARIO. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM EDT MONDAY FOR LEZ040- 041. SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 AM EDT TUESDAY FOR LOZ042-043. SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR LOZ044-045. && $$ SYNOPSIS...TMA NEAR TERM...TMA SHORT TERM...WCH LONG TERM...SMITH/WCH AVIATION...TMA MARINE...TMA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
642 AM EDT SUN MAR 31 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE AREA THIS MORNING. A COLD FRONT WILL FOLLOW TONIGHT. HIGH PRESSURE WILL BUILD IN FOR THE FIRST HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RADAR SHOWS ECHOES MOVING ACROSS THE SOUTHERN PART OF THE FORECAST AREA EARLY THIS MORNING. THESE WILL CONTINUE TO MOVE EAST AND MAY CLEAR THE AREA SHORTLY AFTER DAYBREAK. A TROUGH OF LOW PRESSURE IN INDIANA WILL PUSH ACROSS THE AREA DURING THE MORNING AS WELL. SO FAR ONLY A FEW SHOWERS ALONG AND AHEAD OF IT. BUT RECENT HRRR AND RAP RUNS SUGGEST THAT COVERAGE COULD INCREASE AS IT MOVES INTO THE REGION. THERE SHOULD BE SOME BREAK IN THE CLOUDS AFTER THE TROUGH PASSES AND WINDS COULD GUST UP TO 30 MPH. TRAILING SHORT WAVE WILL MOVE ACROSS THE REGION IN THE AFTERNOON AND CANNOT RULE OUT A FEW ADDITIONAL SHOWERS WITH IT ESPECIALLY IF THERE IS SUFFICIENT HEATING. RAINFALL AMOUNTS TODAY WILL BE LIGHT. HIGHS ARE FORECAST TO BE NEAR PERSISTENCE. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE AREA TONIGHT. APPEARS THAT A FEW SHOWERS COULD ACCOMPANY THE BOUNDARY. 00Z MODELS CONTINUE TO TREND DRIER ON MONDAY. BUT CANNOT COMPLETELY DISCOUNT THE POSSIBILITY OF A SHOWER OR TWO AS A SHORT WAVE DROPS INTO THE BASE OF AN UPPER TROUGH. AT THIS POINT FELT THAT NOTHING MORE THAN SLIGHT CHANCE WAS WARRANTED FOR EITHER TONIGHT OR MONDAY. HIGH PRESSURE WILL RIDGE IN FROM THE NORTHWEST THROUGH THE REMAINDER OF THE PERIOD AS NORTHWEST UPPER FLOW CONTINUES. WITH THE TRANSITION IN AIR MASS TONIGHT LOWS MAY END UP BEING NEAR NORMAL. BUT THEREAFTER READINGS WILL BE BACK TO WELL BELOW SEASONAL AVERAGE. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... UPPER TROUGH WILL DEPART EARLY IN THE PERIOD WITH THE SURFACE HIGH FINALLY BUILDING ACROSS THE AREA. THIS WILL ALLOW TEMPERATURES TO BEGIN TO MODERATE MID WEEK. A WELL DEVELOPED SYSTEM IS FORECAST TO PASS SOUTH OF THE REGION THURSDAY NIGHT AND FRIDAY. THERE IS SOME UNCERTAINTY WITH HOW FAR NORTH THE PRECIPITATION SHIELD WILL SPREAD. BUT WITH THE 00Z ECMWF...CANADIAN AND GEFS MEAN SUGGESTING THAT PRECIPITATION COULD SNEAK UP INTO THE FAR SOUTHEAST COUNTIES...FELT THAT ADDING LOW CHANCE POPS WAS PRUDENT AT THIS POINT. ANOTHER HIGH WILL BUILD IN SATURDAY AFTER THIS SYSTEM PASSES OFF TO THE EAST. TEMPERATURES SHOULD BE NEAR NORMAL FOR THE LATTER PART OF THE WEEK. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... A DISTURBANCE WILL CONTINUE TO WORK THROUGH THE TAF SITES THIS MORNING. COVERAGE IN RAIN SHOWERS WILL DECREASE FROM WEST TO EAST AS THE MORNING PROGRESSES. SOME MVFR VSBYS MAY BE POSSIBLE IN SOME OF THE SHOWER ACTIVITY. AFTER THE MAIN SHOWER ACTIVITY THERE IS AN AREA OF LOWER CIGS AND VSBYS CURRENTLY SW OF THE TAF SITES. HAVE MVFR CIGS AND SOME MVFR VSBYS WORKING INTO THE AREA TODAY. WINDS WILL PICK UP FOR THE DAYTIME HOURS TODAY WITH SOME WIND GUSTS UPWARDS OF 20 TO 25 KNOTS. BY LATE IN THE DAY EXPECT VFR CONDITIONS TO RETURN. ANOTHER DISTURBANCE WILL WORK INTO THE TAF SITES TONIGHT ALLOWING FOR SOME ADDITIONAL LIGHT PRECIPITATION ACROSS THE REGION. EXPECT MVFR CIGS TO AGAIN WORK INTO THE AREA TONIGHT ACROSS THE TAF SITES. OUTLOOK...MVFR CONDITIONS POSSIBLE ON MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...NOVAK
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1000 AM CDT SUN MAR 31 2013 .DISCUSSION...JUST MADE SOME MINOR MODIFICATIONS TO GRIDS (MAINLY MOISTURE AND MINOR AT THAT) BUT OTHERWISE NO REAL CHANGES NEEDED. NEW NAM12 RUN HAS CONVECTION APPROACHING AREA AROUND 00Z BUT THEN WEAKENS IT AS IT MOVES SOUTHWARD. HRRR MODEL HAS CONVECTION TOO BUT FARTHER EAST AND PUSHES IT A BIT FARTHER SOUTH (BUT NOT MUCH). ALL IN ALL...THIS JUSTIFIES MAINTAINING THE 20 POPS OVER THE NORTHERN TIER OF AREA AS PREVIOUSLY FORECAST FOR TODAY. WILL LET TEMPERATURE FORECAST RIDE. WILL UPDATE PFM AND AFM TEXT PRODUCTS BUT ZFPCRP SEEMS OK FOR NOW. && .MARINE...HAVE HAD OBSERVATIONS OF FOG/SEA FOG OVER THE GULF WATERS THIS MORNING...PATCHY DENSE AT TIMES. HAVE WRITTEN MARINE WEATHER STATEMENT TO HIGHLIGHT CONCERN MAINLY FOR TONIGHT AND MONDAY...AS SOME OBSERVATIONS HAVE DEW POINTS AROUND 70F THIS MORNING AND SHELF TEMPS STILL IN THE MID/UPPER 60S. WILL LOOK AT LATER PERIODS ONCE NEW MODEL RUNS AND OBSERVATIONS COME IN. && .PREV DISCUSSION... /ISSUED 626 AM CDT SUN MAR 31 2013/ DISCUSSION...UPDATE FOR 12Z AVIATION. AVIATION...BKN-OVC 500-1500 STRATUS DECK IN PLACE ACROSS EASTERN PORTIONS OF SOUTH TEXAS THIS MORNING...ALONG A HBV-BEA-VCT LINE EAST TO THE COAST. STRATUS DECK WILL GRADUALLY ERODE 15Z-18Z WITH VFR CONDITIONS FOR THIS AFTERNOON. S TO SE WINDS 6-12 KTS INCREASING TO 10-15 KTS AFTER 15Z...AND INCREASING FURTHER AT CRP 15-20 KTS WITH GUSTS TO 25 KTS THIS AFTERNOON. IFR CIGS WILL QUICKLY RE-DEVELOP EARLY THIS EVENING FROM E TO W. PREV DISCUSSION... /ISSUED 351 AM CDT SUN MAR 31 2013/ SHORT TERM (TODAY THROUGH MONDAY)...MID AND UPPER LEVEL SHORTWAVE DIVING SOUTHEAST THROUGH SOUTH-CENTRAL PLAINS EARLY THIS MORNING WITH A SECOND SHORTWAVE TROUGH ACROSS NEW MEXICO TRACKING EAST INTO TEXAS. COLD FRONT HAS ENTERED THE PANHANDLE AND WILL PUSH SOUTH THROUGH WEST-CENTRAL TEXAS THIS MORNING. SOUTH OF THE FRONT ACROSS SOUTH TEXAS...WARM CONDITIONS WILL PREVAIL FOR THIS EASTER SUNDAY. INITIALLY MODELS INDICATING SOME SLIGHT DRYING TAKING PLACE NOW THROUGH 18Z IN THE 925MB-850MB LAYER...BUT THEN MOISTENING BACK UP ACROSS THE CENTRAL AND NORTHERN COUNTIES LATE THIS AFTERNOON...IN ADVANCE OF THE WEAKENING COLD FRONT ENTERING THE HILL COUNTRY AND SOUTH-CENTRAL TEXAS. BACKING LOW LEVEL FLOW AHEAD OF THE SYSTEM MAY YIELD AN ISOLATED SHOWER OR THUNDERSTORMS ACROSS THE CENTRAL COUNTIES LATER THIS AFTERNOON WHERE PWATS POOLED AROUND 1.5"...BUT THE MAIN AREA TO WATCH WILL BE UPSTREAM CONVECTION ACROSS THE EWX CWA CLOSER TO THE FRONT AND SECOND SHORTWAVE. HI RESOLUTIONS MODELS HAVE BEEN INDICATING THIS CONVECTION POSSIBLY MAKING IT INTO THE FAR NORTHERN CWA LATE AFTERNOON/EARLY EVENING...WITH 00Z ECMWF AND 00Z NAM12 ALSO HINTING AT THIS. SHOULD NOTE THAT THE 00Z 4KM ARW/NMM WAS SHOWING CONVECTIVE COMPLEX REACHING THE COAST THIS EVENING BUT AM DISCOUNTING THIS FOR THE TIME BEING...AND THINKING THAT IF CONVECTION MAKES IT INTO THE AREA...IT WOULD LIKELY BE CONFINED TO NORTHERN AND WESTERN AREAS OF THE CWA...AS CIN WOULD BE RAPIDLY INCREASING IN THE EARLY EVENING ACROSS THE COASTAL PLAINS BEHIND THE SEA-BREEZE. GIVEN THE INSTABILITY FORECAST TO DEVELOP LATE AFTERNOON ACROSS THE BRUSH COUNTRY (1700-2000 J/KG CAPE)...STEEP MID LEVEL LAPSE RATES...AND DEEP LAYER SHEAR OF AROUND 50 KTS OVER THE CWA...ISOLATED STRONG TO SEVERE STORMS ARE POSSIBLE. SPC HAS IN FACT EXTENDED SOUTHWARD THE SLIGHT RISK INTO THE CWA...ALONG AND NORTH OF A LINE FROM JUST NORTH OF LAREDO TO ALICE TO VICTORIA. IF CONVECTION DOES DEVELOP OVER OR INTO THE CWA IT SHOULD DIMINISH LATE IN EVENING WITH LOSS OF HEATING. SLIGHTLY COOLER TONIGHT...WITH WINDS BACKED EAST AND NORTHEAST. PATCHY TO AREAS OF FOG DEVELOPING OVERNIGHT. SLIGHTLY COOLER (BUT STILL WARM) ON MONDAY ACROSS SOUTH TEXAS. ECMWF INDICATING QPF ACROSS THE RIO GRANDE PLAINS AND EDWARDS PLATEAU ON MONDAY...WHERE PWATS STILL POOLED NEAR 1.5"...BUT AM KEEPING FORECAST DRY DUE TO LOW CONFIDENCE. LONG TERM (MONDAY THROUGH SATURDAY)...CHALLENGING FORECAST CONTINUES THROUGH THE EXTENDED...HOWEVER EACH NEW MODEL RUN BRINGS THE DIFFERENT GUIDANCE OPTIONS CLOSER TOGETHER...WELL...EXCEPT FOR THE NAM...WHICH IS A PRETTY FAR OUTLIER. WILL FOCUS MAINLY TOWARD THE GFS AND ECMWF THROUGHOUT THE FORECAST. THESE HAVE COME IN QUITE GOOD AGREEMENT WITH FRONTAL PASSAGE TIMING BEING WEDNESDAY AFTERNOON. (THE NAM MUCH FASTER THAN THIS...AND THE CANADIAN A BIT SLOWER.) TOUGH PART OF THE FORECAST IS PRECIP TIMING AND AMOUNTS. COULD SEE SOME ISOLATED ACTIVITY BY MONDAY NIGHT...BUT BETTER CHANCES BEGIN ON TUESDAY. WITH FAVORABLE ISENTROPIC LIFT PATTERN SETTING UP...AND PLENTY OF MOISTURE POOLING ACROSS THE AREA...SEEMS A GOOD CHANCE FOR A WIDESPREAD RAIN ACROSS SOUTH TEXAS. WITH A SUFFICIENTLY WEAKENED CAP WILL HAVE THE POTENTIAL FOR THUNDERSTORMS TUESDAY AND WEDNESDAY. ONE THING NOTABLE SEPARATING THIS EVENT FROM OTHER FRONTS/PRECIP CHANCES WE/VE HAD RECENTLY...WINDS IN THE LOWER LEVELS OF THE ATMOSPHERE STAY SOUTHEAST OR SOUTH THROUGH TUESDAY BEFORE VEERING SOUTHWEST WEDNESDAY MORNING. THIS WOULD ALLOW FOR A MOIST/SATURATED LAYER UP TO AROUND 850MB. HAVE NOT MADE MUCH CHANGE TO PREVIOUS POP FORECAST...MAXING OUT AT 70 POPS ON TUESDAY NIGHT AND EARLY WEDNESDAY...THEN TRAILING OFF WEDNESDAY NIGHT. UNLESS FRONTAL TIMING BACKS UP FURTHER...THINK PRECIP SHOULD BE DONE BY SUNRISE THURSDAY AS UPPER LOW/TROUGH LIFTS OUT OF THE AREA. TOUGH TO MAKE A SPECIFIC CALL ON PRECIP TOTALS AT THIS TIME...BUT CERTAINLY HAVE THE POTENTIAL FOR AN INCH OR MORE OF RAIN FOR SOME OF US...BEST CHANCES BEING THE NORTHEAST PORTION OF THE FORECAST AREA. CURRENTLY HAVE A GENERALLY RANGE OF ONE HALF TO ONE INCH ACROSS THE CWA. AS FAR AS TEMPERATURES...WARMED THINGS UP A BIT ON WEDNESDAY WITH FRONT NOT COMING THROUGH UNTIL THE AFTERNOON...HOWEVER WITH NEARLY OVERCAST SKIES AND PRECIP IN THE AREA WILL BE SEVERAL DEGREES COOLER THAN TUESDAY. WILL ONLY REALLY SEE ONE DAY OF NORTHERLY WINDS/COLD ADVECTION BEHIND THE FRONT BEFORE HIGH PRESSURE RIDGE PUSHES OFF TO THE EAST BY FRIDAY. THUS A COOL DAY ON THURSDAY...BUT GRADUALLY WARMING TEMPS FRIDAY INTO THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 87 64 85 68 81 / 10 10 10 10 40 VICTORIA 83 61 83 65 78 / 20 20 10 20 50 LAREDO 94 68 89 68 86 / 10 10 10 20 40 ALICE 91 64 89 68 82 / 10 10 10 10 40 ROCKPORT 78 64 77 66 77 / 10 10 10 20 40 COTULLA 89 64 88 67 84 / 20 30 10 20 50 KINGSVILLE 89 64 86 67 83 / 10 10 10 10 40 NAVY CORPUS 81 66 79 68 79 / 10 10 10 10 40 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1019 AM MDT SUN MAR 31 2013 .UPDATE...WEAKENING UPPER LEVEL RIDGE WILL PASS ACROSS COLORADO TODAY. THIS WILL KEEP SKIES MOSTLY SUNNY THROUGH THE DAY. MADE SMALL TWEAKS TO THE SKY TO REFLECT THIS. TEMPERATURES APPEAR ON TRACK AND NO OTHER UPDATES ARE PLANNED AT THIS TIME. && .AVIATION...SOUTHERLY WINDS WILL TURN WEST TO NORTHWEST AFTER 18Z. A WEAK COLD FRONT WILL CAUSE WINDS TO SHIFT NORTHEASTERLY TONIGHT AT SPEEDS UNDER 20 KNOTS. MOSTLY CLEAR SKIES WILL PREVAIL THROUGH THE DAY. HIGH CLOUDS WILL INCREASE OVERNIGHT. A LAYER OF STRATUS MAY DEVELOP MONDAY MORNING AROUND 12Z WITH CEILINGS IN THE 2000 TO 3000 FEET RANGE. && .PREV DISCUSSION... /ISSUED 240 AM MDT SUN MAR 31 2013/ SHORT TERM...GENERALLY DRY NW FLOW WILL BE OVER THE AREA THRU THIS AFTN AS SFC LOW PRES DEVELOPS OVER ERN CO. 850-700 MB TEMPS ARE A DEGREE OR TWO WARMER THIS AFTN SO WILL KEEP HIGHS IN THE 65 TO 70 DEGREE RANGE OVER NERN CO. FOR TONIGHT THE FLOW ALOFT WILL BECOME MORE WSW AS A WEAK UPPER LEVEL LOW BEGINS TO MOVE TOWARDS THE GREAT BASIN. SOME MOISTURE WILL INCREASE IN THE MTNS LATE TONIGHT SO WILL MENTION A SLIGHT CHC OF -SHSN WEST OF THE DIVIDE AFTER MIDNIGHT. OVER NERN CO A CDFNT WILL BACKDOOR INTO THE AREA OVERNIGHT HOWEVER OUTSIDE OF SOME INCREASE IN LOW LVL CLOUDS AT THIS TIME DO NOT EXPECT ANY PCPN. LONG TERM...MODELS SLOWER WITH WEAK UPPER LOW. NOW ITS OVER THE FOUR CORNERS FROM 18Z TO 00Z TUESDAY AFTERNOON. IT WEAKENS AND BECOMES AN OPEN TROUGH...ITS AXIS IS OVER EASTERN COLORADO AT 12Z WEDNESDAY MORNING. THE FLOW ALOFT IS PRETTY WEAK ACROSS THE CWA FROM MONDAY NIGHT THROUGH TUESDAY NIGHT. THERE IS UPWARD SYNOPTIC SCALE ENERGY PROGGED FOR THE CWA MONDAY THROUGH TUESDAY NIGHT. THE BOUNDARY LAYER FLOW IS PROGGED TO BE UPSLOPE MONDAY THROUGH MUCH OF TUESDAY NIGHT...WITH EITHER EAST OR SOUTHEAST DIRECTIONS. THE MOISTURE IS NOT AS EXTENSIVE AND PROLONGED AS PREVIOUS MODEL RUNS INDICATED. THE QPF FIELDS DO NOT START MEASURABLE PRECIPITATION UNTIL LATER MONDAY MORNING. MODELS SHOW MEASURABLE PRECIPITATION INTO WEDNESDAY MORNING NOW. THE AMOUNTS ARE LESS THAN YESTERDAY`S 00Z RUNS INDICATED. SO RATHER THAN CHASING THE LATEST/GREATEST MODELS AND AT THE RISK OF CONTINUING TO YO-YO THE FORECAST...WILL CHANGE VERY LITTLE THROUGH TUESDAY NIGHT. TEMPERATURES LOOK CONSIDERABLY WARMER ON MONDAY THAN YESTERDAY`S 00Z RUNS INDICATED. MONDAY`S HIGHS ARE NOW ONLY 4-7 COOLER THAN SUNDAY`S HIGHS. TUESDAY`S HIGHS ARE 1-3 C COOLER THAN MONDAY`S. AGAIN WILL LEAVE THINGS STATUS QUO THIS UPDATE. FOR THE LATER DAYS...WEDNESDAY THROUGH SATURDAY...THERE IS UPPER RIDGING INTO FRIDAY MORNING ..THEN A WEAK UPPER TROUGH MOVES ACROSS FRIDAY NIGHT...AND MORE RIDGING SATURDAY. AVIATION...LIGHT DRAINAGE WINDS THRU THE MORNING HOURS WILL BECOME NWLY BY EARLY AFTN. LATEST RAP SHOWS WINDS COULD GUSTY UP TO 20 MPH FOR A FEW HOURS BETWEEN 22Z AND 00Z BEFORE DECREASING. TONIGHT A CDFNT WILL BACKDOOR INTO THE AREA BETWEEN 03Z AND 06Z WITH WINDS BECOMING MORE NELY. AFTER 06Z WINDS WILL SHIFT TO LIGHT ESE. TOWARDS 12Z MAY SEE SOME STRATUS WITH CEILINGS IN THE 2000-3000 FT RANGE. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM....RJK UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
353 PM EDT SUN MAR 31 2013 .SYNOPSIS... A COLD FRONT WILL MOVE INTO THE FORECAST AREA TONIGHT...BRINGING INCREASED CHANCES OF RAIN. A DRY REINFORCING COLD FRONT WILL MOVE THROUGH THE AREA MONDAY NIGHT AND STALL JUST TO OUR SOUTH TUESDAY. CHANCES OF RAIN INCREASE AGAIN LATE IN THE WEEK AS ANOTHER SYSTEM APPROACHES FROM THE WEST. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... RADAR CURRENTLY INDICATES A BAND OF SCATTERED SHOWERS PUSHING EAST TOWARDS THE CSRA. LATEST RUC TAKES THIS ACTIVITY EAST ACROSS THE FORECAST AREA (FA) OVER THE NEXT FEW HOURS. THEN...POPS AND COVERAGE WILL INCREASE LATER TONIGHT AS A COLD FRONT DRIVEN BY AN UPPER SHORTWAVE PUSHES INTO THE REGION. PRECIPITABLE WATER VALUES CURRENTLY BELOW AN INCH WILL RISE TO NEAR 1.3 INCHES JUST AHEAD OF THE FRONT WITH A 30-40 KT LOW LEVEL JET SUPPORTING MOISTURE TRANSPORT INTO THE AREA. WILL INCREASE POPS TO HIGH LIKELY. SEVERE POTENTIAL SEEMS WEAK BUT CANNOT BE RULED OUT AS THERE IS SOME WEAK INSTABILITY AND SHEAR IS MODERATE...BUT WITH THE LOSS OF HEATING THINK ANY SEVERE THREAT WOULD BE ISOLATED AND LIMITED TO THE SOUTHERN PART OF THE FORECAST AREA. SPC HAS THE AREA OUTLOOKED IN GENERAL THUNDER. TEMPERATURES WILL BE SLOW TO FALL OVERNIGHT DUE TO CLOUD COVER...PRECIPITATION AND WINDS STAYING UP A BIT. OVERNIGHT LOWS SHOULD BE ABOVE NORMAL WELL IN THE 50S. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... MONDAY...MODELS SHOW WEAK SHORT WAVE MOVING THROUGH REGION LATE TONIGHT THROUGH MONDAY MORNING. WILL CARRY HIGHEST POPS DURING THIS PERIOD WITH 50-60 PERCENT CHANCE MONDAY MORNING...DROPPING TO 20-30 PERCENT BY MONDAY AFTERNOON. WEAK WARM FRONT THAT MOVED NORTHWARD SUNDAY IS EXPECTED TO BE PICKED UP BY THE SHORT WAVE AND MOVED EAST DURING THE DAY MONDAY. WESTERLY WINDS 5-10 KNOTS BEHIND THE FRONT SHOULD BRING DRIER AIR TO THE REGION. THIS WILL BE REFLECTED BY LOWER POPS MONDAY AFTERNOON. NOT MUCH IN THE WAY OF COLD AIR ADVECTION BEHIND WEAK COLD FRONT MONDAY. WITH SUNSHINE MONDAY AFTERNOON...HIGH TEMPERATURES ARE EXPECTED TO RISE INTO THE MIDDLE TO UPPER 70S. THIS WILL HELP THE ATMOSPHERE TO BECOME MORE UNSTABLE ESPECIALLY BY EARLY MONDAY AFTERNOON. STILL A MENTION OF SHOWERS AT THIS TIME. AND WITH STABILITY PARAMETERS SHOWING LIS -1/-2...TOTALS NEAR 45...PW VALUES NEAR 1 INCH AND CAPES NEAR 600 J/KG...THERE MAY BE A FEW THUNDERSTORMS AROUND. HOWEVER... WITH WEAK INSTABILITY...DO NOT EXPECT ANY STRONG OR SEVERE STORMS TO DEVELOP. ACTUALLY...SPC JUST HAS A GENERAL THUNDERSTORM AREA OVER THE SOUTHERN PART OF THE FORECAST AREA. AFTER 18Z MONDAY AFTERNOON...THERE IS ADDITIONAL DRYING WITH PW VALUES DROPPING TO AROUND 0.70 OF AN INCH AND A WEAK MID LEVEL CAP. MONDAY EVENING...A BETTER DEFINED COLD FRONT DROPS TO THE SOUTH WITH AT LEAST A TEMPERATURE GRADIENT. IT HAS SOME MOISTURE AT FIRST BUT LOSES JUST ABOUT ALL THE MOISTURE AS IN MOVES ACROSS THE APPALACHIAN MOUNTAINS IN NORTH CAROLINA. SO THE FRONT WILL MOVE THROUGH MONDAY NIGHT DRY. COOLER MONDAY NIGHT WITH LOWS IN THE MIDDLE TO UPPER 40S. TUESDAY AND TUESDAY NIGHT...HIGH PRESSURE WITH COOLER DRIER AIR. HIGHS MAINLY IN THE MIDDLE 60S WITH LOWS TUESDAY NIGHT MAINLY IN THE MIDDLE 40S. THERE MAY BE SOME INCREASE IN HIGH AND MID LEVEL CLOUDINESS LATE TUESDAY NIGHT AS A NEW WEATHER SYSTEM BEGINS TO APPROACH FROM THE WEST. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... MEDIUM RANGE MODELS IN GOOD AGREEMENT AT LEAST EARLY IN THE EXTENDER PERIOD WEDNESDAY. MODELS THEN BRING A SYSTEM OUT OF THE GULF OF MEXICO THURSDAY AND FRIDAY. THE GFS HAS A STRONGER SYSTEM AND MORE PROGRESSIVE SYSTEM BUT BOTH THE GFS AND ECMWF BRING THE LOW UP THE CAROLINA COAST. A WEDGE PATTERN IS EXPECTED THURSDAY. AS THE SYSTEM MOVES FARTHER TO THE NORTHEAST...COLD AIR ADVECTION WITH NORTHERLY WINDS AND WRAP AROUND MOISTURE ARE EXPECTED ON FRIDAY. THE SYSTEM IS GONE BY THE WEEKEND AND HIGH PRESSURE AND DRIER AIR FOR THE WEEKEND. TEMPERATURES ARE EXPECTED TO BE WELL BELOW NORMAL FOR MOST OF THE PERIOD EXCEPT MAYBE RETURNING TO CLOSE TO NORMAL BY SUNDAY. WILL HAVE THURSDAY AS THE COOLEST DAY WITH A WEDGE AND HIGHS MAINLY IN THE LOWER 50S. DEPENDING ON ANY EVAPORATIVE COOLING WITH THE RAINFALL... THURSDAY MAY BE COOLER. FRIDAY IS STILL FAIRLY COOL WITH HIGHS IN THE UPPER 50S. WITH THE RETURN OF SUNSHINE...THE WEEKEND PROMISES TO BE WARMER. HIGHS IN THE MIDDLE 60S SATURDAY AND HIGHS AROUND 70 SUNDAY. OVERNIGHT LOWS SHOULD BE MOSTLY IN THE 40S FOR MUCH OF THE EXTENDED PERIOD. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS EXPECTED THROUGH THIS EVENING...FOLLOWED BY DETERIORATING CONDITIONS LATER TONIGHT AND MONDAY MORNING. SCATTERED SHOWERS DEVELOPING WITH DAYTIME HEATING AND WARM ADVECTION WILL AFFECT THE MIDLANDS AND CSRA. COULD SEE MVFR OR LOWER CONDITIONS IN SHOWERS...BUT PROBABILITY AND CONFIDENCE TOO LOW TO INCLUDE AT THIS TIME. WILL AMEND TAFS AS NEEDED. A COLD FRONT WILL MOVE INTO THE AREA OVERNIGHT...SO EXPECT WIDESPREAD RAIN TO OVERSPREAD THE TERMINALS BEGINNING AROUND 05Z WITH DETERIORATING MVFR/IFR CONDITIONS WHICH SHOULD HOLD THROUGH AROUND 15Z. THUNDERSTORMS CANNOT BE RULED OUT BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN FORECAST. WINDS WILL REMAIN SOUTHWESTERLY AROUND 10-15 MPH WITH GUSTS TO 25 MPH LATE THIS AFTERNOON...THEN DECREASING OVERNIGHT AND SHIFTING TO THE WEST BY 12Z. EXTENDED AVIATION OUTLOOK...NO RESTRICTIONS TO AVIATION EXPECTED. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
352 PM EDT SUN MAR 31 2013 .SYNOPSIS... A COLD FRONT WILL MOVE INTO THE FORECAST AREA TONIGHT...BRINGING INCREASED CHANCES OF RAIN. A DRY REINFORCING COLD FRONT WILL MOVE THROUGH THE AREA MONDAY NIGHT AND STALL JUST TO OUR SOUTH TUESDAY. CHANCES OF RAIN INCREASE AGAIN LATE IN THE WEEK AS ANOTHER SYSTEM APPROACHES FROM THE WEST. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... RADAR CURRENTLY INDICATES A BAND OF SCATTERED SHOWERS PUSHING EAST TOWARDS THE CSRA. LATEST RUC TAKES THIS ACTIVITY EAST ACROSS THE FORECAST AREA (FA) OVER THE NEXT FEW HOURS. THEN...POPS AND COVERAGE WILL INCREASE LATER TONIGHT AS A COLD FRONT DRIVEN BY AN UPPER SHORTWAVE PUSHES INTO THE REGION. PRECIPITABLE WATER VALUES CURRENTLY BELOW AN INCH WILL RISE TO NEAR 1.3 INCHES JUST AHEAD OF THE FRONT WITH A 30-40 KT LOW LEVEL JET SUPPORTING MOISTURE TRANSPORT INTO THE AREA. WILL INCREASE POPS TO HIGH LIKELY. SEVERE POTENTIAL SEEMS WEAK BUT CANNOT BE RULED OUT AS THERE IS SOME WEAK INSTABILITY AND SHEAR IS MODERATE...BUT WITH THE LOSS OF HEATING THINK ANY SEVERE THREAT WOULD BE ISOLATED AND LIMITED TO THE SOUTHERN PART OF THE FORECAST AREA. SPC HAS THE AREA OUTLOOKED IN GENERAL THUNDER. TEMPERATURES WILL BE SLOW TO FALL OVERNIGHT DUE TO CLOUD COVER...PRECIPITATION AND WINDS STAYING UP A BIT. OVERNIGHT LOWS SHOULD BE ABOVE NORMAL WELL IN THE 50S. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... MONDAY...MODELS SHOW WEAK SHORT WAVE MOVING THROUGH REGION LATE TONIGHT THROUGH MONDAY MORNING. WILL CARRY HIGHEST POPS DURING THIS PERIOD WITH 50-60 PERCENT CHANCE MONDAY MORNING...DROPPING TO 20-30 PERCENT BY MONDAY AFTERNOON. WEAK WARM FRONT THAT MOVED NORTHWARD SUNDAY IS EXPECTED TO BE PICKED UP BY THE SHORT WAVE AND MOVED EAST DURING THE DAY MONDAY. WESTERLY WINDS 5-10 KNOTS BEHIND THE FRONT SHOULD BRING DRIER AIR TO THE REGION. THIS WILL BE REFLECTED BY LOWER POPS MONDAY AFTERNOON. NOT MUCH IN THE WAY OF COLD AIR ADVECTION BEHIND WEAK COLD FRONT MONDAY. WITH SUNSHINE MONDAY AFTERNOON...HIGH TEMPERATURES ARE EXPECTED TO RISE INTO THE MIDDLE TO UPPER 70S. THIS WILL HELP THE ATMOSPHERE TO BECOME MORE UNSTABLE ESPECIALLY BY EARLY MONDAY AFTERNOON. STILL A MENTION OF SHOWERS AT THIS TIME. AND WITH STABILITY PARAMETERS SHOWING LIS -1/-2...TOTALS NEAR 45...PW VALUES NEAR 1 INCH AND CAPES NEAR 600 J/KG...THERE MAY BE A FEW THUNDERSTORMS AROUND. HOWEVER... WITH WEAK INSTABILITY...DO NOT EXPECT ANY STRONG OR SEVERE STORMS TO DEVELOP. ACTUALLY...SPC JUST HAS A GENERAL THUNDERSTORM AREA OVER THE SOUTHERN PART OF THE FORECAST AREA. AFTER 18Z MONDAY AFTERNOON...THERE IS ADDITIONAL DRYING WITH PW VALUES DROPPING TO AROUND 0.70 OF AN INCH AND A WEAK MID LEVEL CAP. MONDAY EVENING...A BETTER DEFINED COLD FRONT DROPS TO THE SOUTH WITH AT LEAST A TEMPERATURE GRADIENT. IT HAS SOME MOISTURE AT FIRST BUT LOSES JUST ABOUT ALL THE MOISTURE AS IN MOVES ACROSS THE APPALACHIAN MOUNTAINS IN NORTH CAROLINA. SO THE FRONT WILL MOVE THROUGH MONDAY NIGHT DRY. COOLER MONDAY NIGHT WITH LOWS IN THE MIDDLE TO UPPER 40S. TUESDAY AND TUESDAY NIGHT...HIGH PRESSURE WITH COOLER DRIER AIR. HIGHS MAINLY IN THE MIDDLE 60S WITH LOWS TUESDAY NIGHT MAINLY IN THE MIDDLE 40S. THERE MAY BE SOME INCREASE IN HIGH AND MID LEVEL CLOUDINESS LATE TUESDAY NIGHT AS A NEW WEATHER SYSTEM BEGINS TO APPROACH FROM THE WEST. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... MEDIUM RANGE MODELS IN GOOD AGREEMENT AT LEAST EARLY IN THE EXTENDER PERIOD WEDNESDAY. MODELS THEN BRING A SYSTEM OUT OF THE GULF OF MEXICO THURSDAY AND FRIDAY. THE GFS HAS A STRONGER SYSTEM AND MORE PROGRESSIVE SYSTEM BUT BOTH THE GFS AND ECMWF BRING THE LOW UP THE CAROLINA COAST. A WEDGE PATTERN IS EXPECTED THURSDAY. AS THE SYSTEM MOVES FARTHER TO THE NORTHEAST...COLD AIR ADVECTION WITH NORTHERLY WINDS AND WRAP AROUND MOISTURE ARE EXPECTED ON FRIDAY. THE SYSTEM IS GONE BY THE WEEKEND AND HIGH PRESSURE AND DRIER AIR FOR THE WEEKEND. TEMPERATURES ARE EXPECTED TO BE WELL BELOW NORMAL FOR MOST OF THE PERIOD EXCEPT MAYBE RETURNING TO CLOSE TO NORMAL BY SUNDAY. WILL HAVE THURSDAY AS THE COOLEST DAY WITH A WEDGE AND HIGHS MAINLY IN THE LOWER 50S. DEPENDING ON ANY EVAPORATIVE COOLING WITH THE RAINFALL... THURSDAY MAY BE COOLER. FRIDAY IS STILL FAIRLY COOL WITH HIGHS IN THE UPPER 50S. WITH THE RETURN OF SUNSHINE...THE WEEKEND PROMISES TO BE WARMER. HIGHS IN THE MIDDLE 60S SATURDAY AND HIGHS AROUND 70 SUNDAY. OVERNIGHT LOWS SHOULD BE MOSTLY IN THE 40S FOR MUCH OF THE EXTENDED PERIOD. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
135 PM EDT SUN MAR 31 2013 .UPDATE... /ISSUED AT 1022 AM EDT SUN MAR 31 2013/ A FEW SHOWERS LINGER OVER TOOMBS COUNTY BUT THESE ARE MOVING QUICKLY TO THE EAST. AN AREA OF SHOWERS AND ISOLATED TSTORMS OVER CENTRAL AL IS HOLDING TOGETHER AND SHOULD MOVE INTO WEST CENTRAL GA AROUND NOON. MODELS NOT HANDLING THIS AS WELL...ALTHOUGH THE HRRR DOES HAVE THE AREA OF SHOWERS BUT TOO FAR NORTH. THE 2ND WAVE OVER OK/AR STILL PROGGED TO MOVE INTO THE CWA LATE THIS AFTERNOON/THIS EVENING. TEMPS STILL LOOK ON TARGET. EVEN WITH THE CLOUDS THERE IS STILL SOME GOOD WAA TODAY. OTHER THAN ADJUSTING THE POPS...NO OTHER CHANGES PLANNED. && .SHORT TERM /TODAY THROUGH MONDAY/... /ISSUED AT 740 AM EDT SUN MAR 31 2013/ SHORT WAVE CURRENTLY MOVING THROUGH OHIO/TN VALLEY AREA. SHOWERS ASSOCIATED WITH THIS FEATURE WILL CONTINUE TO MOVE EAST THROUGH THE CWA THIS MORNING. SHOWERS SHOULD DIMINISH THROUGH THE MORNING AND MODELS INDICATE A BREAK BETWEEN THIS WAVE AND THE NEXT ONE WHICH SHOULD AFFECT US STARTING THIS AFTERNOON. HAVE INCREASED POPS AGAIN STARTING AROUND 18Z AND CONTINUE WITH LIKELY POPS FOR MUCH OF THE CWA THROUGH 06Z MONDAY. INSTABILITY INCREASES ALSO DURING THIS AFTERNOON WITH BEST CAPE AND LIFTED INDEX VALUES 18Z TODAY THROUGH 06Z MONDAY. HAVE CONTINUED WITH MENTION OF THUNDER DURING THAT TIME. UPPER TROUGH DEEPENING OVER THE NORTHERN STATES SHOULD PUSH A SURFACE BOUNDARY INTO NORTH GA LATE TONIGHT AND INTO MONDAY. SOME DRYING SHOULD OCCUR BEHIND THIS BOUNDARY AND HAVE ENDED SHOWERS FROM THE NORTH MONDAY MORNING WITH SOME POPS CONTINUING THROUGH THE CENTRAL ZONES INTO THE AFTERNOON. TEMPERATURES CONTINUE WARM THROUGH THE SHORT TERM AND HAVE TAKEN A BLEND OF THE MAV/MET. 41 .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... /ISSUED AT 740 AM EDT SUN MAR 31 2013/ NEXT MAIN RAIN EVENT WILL ENCOMPASS THE SECOND HALF OF THE WEEK. GFS/EUROPEAN SIMILAR WITH BRINGING RAIN TO THE AREA POSSIBLY AS EARLY AS TUESDAY NIGHT/WEDNESDAY BUT MORE SO WEDNESDAY NIGHT INTO FRIDAY. A WARM FRONT DEVELOPS ALONG THE GULF COAST WITH OVERRUNNING MOIST FLOW SETTING UP. THE MAIN DIFFERENCE BETWEEN THE GFS AND EUROPEAN IS THE EUROPEAN BRINGS SURFACE LOW PRESSURE ACROSS CENTRAL TO S GA THURSDAY NIGHT AND FRIDAY WHILE THE GFS TAKES THE SURFACE LOW ACROSS N FL. GFS BRINGS ONLY MINIMAL MUCAPE INTO CENTRAL GA THURSDAY/THURSDAY NIGHT. IF THE EUROPEAN SURFACE SOLUTION COMES TO PASS THE CHANCES FOR THUNDERSTORMS WOULD BE GREATER WITH THE WARM FRONT POSSIBLY GETTING INTO CENTRAL GA WITH A LOW END THREAT FOR SEVERE WEATHER. EITHER WAY A GOOD RAIN EVENT WITH 1 TO 2 INCHES ACROSS CENTRAL GA. THE UPPER TROUGH MOVES TO THE AREA FRIDAY WITH THE GFS A LITTLE FASTER WITH THE TROUGH AND MOISTURE EXITING THAN THE EUROPEAN. A DAMPENING SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE MOVE TO THE AREA SATURDAY WITH DRY CONDITIONS EXPECTED AND THIS LOOKS TO CONTINUE FOR SUNDAY. BDL && .AVIATION... 18Z UPDATE... SCATTERED SHOWERS REMAINING FROM THIS MORNINGS CONVECTION OVER ALABAMA WILL CONTINUE ACROSS THE FORECAST AREA THIS AFTERNOON. AS SURFACE HEATING INCREASES LATE THIS AFTERNOON...ISOLATED TSRA WILL DEVELOP. THE NEXT SHORT WAVE WILL MOVE INTO THE AREA THIS EVENING BRINGING SHOWERS AND SCATTERED THUNDERSTORMS. PRECIP WILL END FROM THE NORTH AFTER MIDNIGHT. PLENTY OF LOW LEVEL MOISTURE TONIGHT WILL KEEP CIGS BELOW 1000 FT MOST AREAS. CIGS WILL RISE TO VFR BY 18Z MON ALL AREAS AND REMAIN VFR THROUGH MONDAY AFTERNOON. SOUTHWEST WINDS WILL BECOME LIGHT THIS EVENING...THEN NORTHWEST AFTER FROPA LATE TONIGHT. WIND SPEEDS WILL INCREASE MONDAY MORNING WITH GUSTS TO 15 TO 20KTS MONDAY AFTERNOON. //ATL CONFIDENCE...18Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. 17 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 71 53 75 46 / 40 60 10 10 ATLANTA 70 54 73 50 / 50 60 10 10 BLAIRSVILLE 63 47 69 39 / 50 60 10 20 CARTERSVILLE 69 50 72 43 / 60 60 10 10 COLUMBUS 76 58 77 52 / 50 70 30 5 GAINESVILLE 69 51 74 47 / 40 60 10 10 MACON 76 57 77 48 / 40 70 30 5 ROME 70 50 73 43 / 60 60 10 20 PEACHTREE CITY 71 52 74 45 / 50 60 10 5 VIDALIA 78 60 77 53 / 30 70 60 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...41 LONG TERM....BDL AVIATION...41
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1225 PM CDT SUN MAR 31 2013 .UPDATE... ISSUED AT 1221 PM CDT SUN MAR 31 2013 UPDATED THE AVIATION SECTION FOR THE 18Z TAF ISSUANCE. && UPDATE ISSUED AT 701 AM CDT SUN MAR 31 2013 LATEST RADAR TRENDS SHOW ANY THUNDER THREAT GETTING SHUNTED TO OUR WEST AND SOUTHWEST. THE FRESHEST DEVELOPMENT IS IN NORTHERN ARKANSAS...WHICH MAY SPELL A RAPID END TO THE MISSOURI CONVECTION EARLY THIS MORNING. SOME SHORT TERM GUIDANCE PUSHES THE NORTHERN ARKANSAS CONVECTION MORE TO THE EAST...POTENTIALLY IMPACTING OUR ENTIRE SOUTHERN BORDER WITH TIME THROUGH THE DAY. BEST GUESS IS THAT AREAS ALONG AND WEST OF A LINE FROM MARBLE HILL MISSOURI TO FULTON KENTUCKY LINE COULD SEE SOME TANGIBLE SHOWERS THIS MORNING. UPDATED TO BRING CHANCE POPS SOUTHEAST ACROSS THIS AREA THROUGH THE MORNING. AREAS NEAR THE TENNESSEE BORDER COULD SEE A STRAY SHOWER EARLY THIS AFTERNOON. THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z TAF ISSUANCE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 406 AM CDT SUN MAR 31 2013 CONSIDERED A DENSE FOG ADVISORY FOR WESTERN PORTIONS OF SOUTHEAST MISSOURI DUE TO KPOF REPORTING 1/2 MILE OR LESS...BUT IT SEEMS TO BE IMPROVING A BIT IN THE LAST HOUR AND WE HAVE LITTLE CLUE HOW WIDESPREAD IT IS. WILL KEEP AN EYE ON IT...BUT FOR NOW WILL JUST LET IT BE. WEAK ECHOES FOR LIGHT RAIN HAVE JUST ABOUT PUSHED EAST OF THE EVANSVILLE TRI STATE...BUT THERE MAY BE JUST A BIT LINGERING IN THE KOWB AREA. THIS SHOULD COME TO AN END SHORTLY. OF GREATER CONCERN IS THE AREA OF SHOWERS AND THUNDERSTORMS MOVING EAST SOUTHEAST ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI. HAD TO LEAN ON THE HRRR MODEL SIMULATED REFLECTIVITY TO REPRESENT THIS IN THE GRIDS. IN GENERAL WOULD EXPECT THE AREA TO WEAKEN AS IT MOVES INTO OUR REGION JUST AFTER SUNRISE...SO WILL HAVE 20-30 POPS FOR NOW...GENERALLY SWEEPING ACROSS OUR SOUTHWEST HALF 14Z- 20Z. THIS WEAKENING TREND IS SUPPORTED BY THE 06Z NAM...WHICH KEEPS ANY INSTABILITY TO OUR WEST AND SOUTHWEST. WILL HAVE TO KEEP A CLOSE EYE ON THIS SITUATION AS WELL AND BE PREPARED TO UPDATE IF/WHEN IT BECOMES NECESSARY. TEMPERATURES EARLY THIS MORNING ARE NEARLY STEADY...SO WE WILL HAVE A MILD START TO THE DAY...WHICH IS GOOD BECAUSE THE LOW CLOUDS/FOG AND EVENTUALLY SOME SHOWERS WILL DELAY WARMING THROUGH THE MORNING. TRIED TO CAPTURE THIS TREND IN THE TEMPERATURE GRIDS...BUT WE SHOULD JUMP UP WELL INTO THE 60S WITH SOME SUNSHINE THIS AFTERNOON. STAYED CLOSE TO CONSENSUS. LIKE THE 00Z AND 06Z NAM WITH THE REAL COLD FRONT/SURFACE HIGH SURGE THROUGH THE AREA LATE TONIGHT AND MONDAY...AS IT SHOULD HANDLE THE SHALLOW COLD AIRMASS BETTER THAN THE LESSER RESOLVED GFS. THE NAM DOES GENERATE SOME VERY MEAGER QPF OVER THE EVANSVILLE TRI STATE TONIGHT WITH THE INITIAL WIND SHIFT...BUT THE GFS IS DRY. DECIDED TO MENTION SOME SPRINKLES IN THAT AREA THROUGH THE NIGHT...BUT DID NOT INTRODUCE A MEASURABLE POP. CONSENSUS OF GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON TEMPERATURES TONIGHT. TEMPERATURES ONLY FALL INTO THE UPPER 30S IN THE NORTH...SO LITTLE CHANCE OF FLURRIES WITH THE SPRINKLES TONIGHT. FOR MONDAY...THE MODELS CONTINUE TO TREND DRIER AND DRIER FOR OUR AREA. SIMILAR TO TONIGHT...DECIDED TO JUST PLASTER A CHANCE OF SPRINKLES ACROSS THE ENTIRE AREA THROUGH THE DAY...IN LIEU OF A VERY SMALL MEASURABLE POP. TEMPERATURES WILL SUPPORT ALL LIQUID THROUGH THE DAY. FIGURE WITH THE SURGE CONSISTENTLY ADVERTISED IN THE NAM RUNS...THAT TEMPERATURES WILL BE COOLER THAN MOST GUIDANCE INDICATES. STAYED ON THE LOW SIDE OF GUIDANCE CLOSER TO THE NAM/MET...BUT THAT MAY NOT BE COOL ENOUGH. MONDAY NIGHT WILL BE DRY...BUT WE WILL REMAIN IN CYCLONIC WEST NORTHWEST FLOW ALOFT...SO CANNOT RULE OUT SOME LIGHT PRECIPITATION...ESPECIALLY OVER OUR SOUTHWEST MONDAY NIGHT INTO TUESDAY. THE GFS IS THE MOST AGGRESSIVE IN GENERATING LIGHT QPF WITH SOME FRONTOGENETIC FORCING IN THE 850-700MB LAYER IN THE FAR SOUTHWEST. INTRODUCED SOME VERY SMALL POPS NEAR THE ARKANSAS BORDER AND THE BOOT HEEL REGION JUST TO BE SAFE. LATELY...IF THERE IS ANY CHANCE OF US GETTING WET IT SEEMS TO HAPPEN. TEMPERATURES IN THAT AREA SHOULD BE NO LOWER THAN THE MIDDLE 30S...SO KEPT THIS ALL RAIN AS WELL. CONSENSUS TEMPERATURES LOOKED FINE MONDAY NIGHT AND TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 406 AM CDT SUN MAR 31 2013 THIS EXTENDED PERIOD FOR THIS FORECAST ISSUANCE WILL SERVE AS THE TRANSITION OF EXTREMES IN TEMPERATURE FROM NEAR RECORD LOWS WEDNESDAY MORNING TO ABOVE NORMAL /MIDDLE 60S/ HIGHS NEXT WEEKEND. GIVEN THE BELOW NORMAL TEMPERATURES WE HAVE BEEN EXPERIENCING IN MARCH...TEMPERATURES AT OR ABOVE NORMAL WILL BE A WELCOME CHANGE. THE ONLY WEATHER MAKER OF CONSEQUENCE WILL OCCUR THURSDAY/THURSDAY NIGHT. ANY MEASURABLE POPS AND WEATHER /GENERALLY SLIGHT IN CATEGORY/ WILL BE LIMITED TO WEST KENTUCKY AND A SMALL PART OF THE SOUTHEAST MISSOURI BOOTHILL. THE SOURCE REGION FOR THIS SYSTEM IS THE CLOSED LOW CURRENTLY OFF THE CALIFORNIA COAST. THIS FEATURE IS EXPECTED TO PUSH TOWARD THE CENTRAL ROCKIES AND DIVE EAST-SOUTHEAST INTO THE LOWER MISSISSIPPI VALLEY. DURING THE PAST 3-4 DAYS...THE NORTHERN EDGE OF THIS CLOSED LOW/WAVE HAS BEEN FORECAST BY THE GFS/ECMWF/GEM GUIDANCE TO SKIRT ALONG THE SOUTHERN BORDER OF THE WFO PAH FORECAST AREA. THERE HAS BEEN ENOUGH MODEL RUNS TO STILL INDICATE THAT VERY FEW LOCATIONS WILL SEE ANY RAIN...IF ANY...ON THURSDAY. THE MAIN IMPACT WILL BE CLOUD COVER...WITH A SHARP DEMARCATION LINE ON THE NORTHERN EDGE OF THE DEFORMATION ZONE ASSOCIATED WITH THE LOW/WAVE. NORTHEAST WINDS DURING THIS TIME PERIOD MAY TEMPER HIGHS SOMEWHAT. WITH HIGH PRESSURE DOMINATING THE REGION THROUGH MOST OF THE PERIOD...CLOUD COVER WILL BE MINIMAL OUTSIDE OF THE DISTURBANCE ON THURSDAY. THIS WILL SET THE STAGE FOR GOOD INSOLATION/DRY AIR ADVECTION AND EVAPORATION. A MANUAL UPWARD ADJUSTMENT WAS MADE TO THE MAX TEMPERATURES FROM FRIDAY THROUGH SUNDAY TO ACCOUNT FOR A LARGER DIURNAL RANGE /25-27 DEGREES F/IN TEMPERATURES WITH THE DRIER AIR IN PLACE ACROSS THE WFO PAH FORECAST AREA. AS A SIDE NOTE...MIN FORECAST TEMPERATURES WEDNESDAY MORNING LOOK LIKE THEY MAY BE ONE TO TWO DEGREES HIGHER THAN THE RECORD TEMPERATURES ON THE BOOKS. SUBTLE MICRO-CLIMATE CHANGES AROUND THE OBSERVATION SITES WILL DETERMINE WHETHER ANY RECORDS ARE TIED OR SET WEDNESDAY MORNING. && .AVIATION... ISSUED AT 1221 PM CDT SUN MAR 31 2013 VFR CONDITIONS EXPECTED AT KCGI/KPAH THROUGH THE PERIOD. MVFR CIGS EARLY AT KEVV/KOWB WILL BECOME VFR BY 20-21Z. WEST TO NORTHWEST WINDS AOB 10 KTS WILL GRADUALLY VEER AROUND TO THE NORTH BY THE END OF THE PERIOD. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM/FIRE WX...MY LONG TERM/AVIATION...JP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
453 PM EDT SUN MAR 31 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 451 PM EDT SUN MAR 31 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF DEEPENING INTO THE GREAT LAKES REGION. VIGOROUS SHORTWAVE WAS PASSING OVER LAKE SUPERIOR. PER SATELLITE IMAGERY AND CANADIAN RADAR IMAGERY...AN ASSOCIATED IMPRESSIVE LOOKING SMALL SWATH OF MDT TO HVY SNOW HAS PASSED JUST N OF THE FCST AREA ACROSS FAR NRN LAKE SUPERIOR/ADJACENT ONTARIO TODAY...ALONG/JUST N OF SHORTWAVE TRACK. AN INCREASINGLY WELL-DEFINED SFC LOW PRES IS ORGANIZING OVER EASTERN LAKE ATTM PER VIS SATELLITE IMAGERY. TO THE S...-SHSN TODAY HAVE DEFINITELY TAKEN ON A SPRINGTIME DIURNAL LAND BASED LOOK WITH UNORGANIZED SCT/NMRS COVERAGE. WELL-MIXED LAYER HAS PREVENTED SOME OF THE PCPN FROM REACHING THE GROUND. UPSTREAM 12Z KINL SOUNDING SHOWED A DEEP MOISTURE PROFILE TO 650MB (AROUND 11KFT)... AND MODIFYING SOUNDING FOR A SFC T/TD IN THE LWR 30S/LWR 20S YIELDED SBCAPE AROUND 100J/KG...AND THUS THE DIURNAL COMPONENT TO THE -SHSN THIS AFTN. MAIN FCST ISSUES TONIGHT/MON ARE POTENTIAL LES ACCUMULATIONS AS WELL AS WINDS. FIRST UP...WINDS. EXPECT STRONGEST WINDS TO OCCUR FROM NOW THRU THE ABOUT MID EVENING AS AREA OF 4MB/3HR PRES RISES CURRENTLY JUST NW OF LAKE SUPERIOR SETTLES SE. THE DEEPENING INCREASINGLY WELL-DEFINED SFC LOW OVER ERN LAKE SUPERIOR IS A CONCERN AS IT WILL SERVE TO STRENGTHEN ISALLOBARIC WINDS. SOME OF THE HIGHER RES MODEL GUIDANCE SEEMS TO BE PICKING UP ON THIS AS A SMALL 5-6MB/3HR PRES RISE MAX DEVELOPS OVER CNTRL/ERN LAKE SUPERIOR WITHIN THE LARGER SCALE PRES RISES. THE IMPACT OF THE DEEPENING LOW HAS ALREADY MADE AN IMPACT AS WINDS HAVE GUSTED TO 50MPH AT KP59. THIS SHOULD BE A GOOD INDICATION OF WHAT IS TO COME IN THE NEXT FEW HRS TO THE E OF MARQUETTE. WIND ADVY HAS BEEN ISSUED FOR KEWEENAW COUNTY INTO MID EVENING TO ACCOUNT FOR STRONG WINDS OVER THE NEXT FEW HRS. AS FOR SNOW...NNW CYCLONIC FLOW SHOULD ALLOW SOME OF THE DEEPER MOISTURE IN NRN ONTARIO PER 12Z CWPL SOUNDING WHICH SHOWED DEEP MOISTURE TO 425MB (20500FT) TO SLIP INTO THE UPPER LAKES. WITH 850MB TEMPS FALLING TO -18C BY 12Z MON...A 3KFT THICK DGZ LAYER FALLS NICELY INTO THE CONVECTIVE LAYER WHERE NAM INDICATES RATHER VIGOROUS UPWARD MOTION TONIGHT. WITH EQUILIBRIUM LEVELS LIKELY ABOVE 10KFT... LES SHOULD GET GOING AT A PRETTY GOOD CLIP...BUT THE LES WILL LIKELY TAKE SOME TIME TO GET FULLY DEVELOPED AND ORGANIZED AS THE TYPICAL DISRUPTIVE EFFECTS OF SPRING DAYTIME HEATING ON LES WILL NEED TO BE ERODED AWAY FIRST. ALTHOUGH IT`S NOT ESPECIALLY COLD YET...NOTE THAT THE LAKE IS HAVING MORE OF A STABILIZING INFLUENCE WITH LESS CLOUD OVER THE WATER THAN LAND...EXCEPT RIGHT IN THE VCNTY OF THE SFC LOW. THE OVERNIGHT PERIOD THRU MON MORNING SHOULD BE THE PRIME PERIOD OF LES...AND THE GOING ADVY LOOKS ON TRACK FOR THE ERN COUNTIES ALONG LAKE SUPERIOR. WILL PROBABLY SEE SOME ACCUMULATIONS UP TO 6-7 INCHES BY MON AFTN. CONSIDERABLE BLSN WILL ALSO BE AN ISSUE...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR. THE W WILL BE MORE ON THE FRINGE OF THE DEEPER MOISTURE PLUS FCST SOUNDINGS SHOW MORE OF A WELL MIXED BOUNDARY LAYER LINGERING THRU THE NIGHT WHICH ARGUES FOR LIGHTER LES THAN OVER THE E. ACCUMULATIONS TONIGHT THRU EARLY MON AFTN SHOULD BE IN THE 1-4 INCH RANGE OVER THE W... INCLUDING INTO THE HIGHER TERRAIN OF NW MARQUETTE COUNTY. CONDITIONS REMAIN FAVORABLE FOR LES MON AS 850MB TEMPS ONLY RISE A DEGREE OR TWO IN THE AFTN. MOISTURE PROFILE REMAINS DEEP OVER THE E...BUT DOES BECOME MORE SHALLOW OVER THE W. SO LES WILL DIMINISH OVER THE W. EVEN OVER THE E...EXPECT LES TO BEGIN TO DIMINISH IN THE AFTN AS STRONG DAYTIME HEATING DISRUPTS LES PROCESSES. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 451 PM EDT SUN MAR 31 2013 LAKE EFFECT WILL BE ONGOING AT THE START OF THE LONGER TERM PERIOD ON MONDAY NIGHT. INVERSIONS 6-8KFT AND DELTA T/S AROUND 18C WITH LAKE EQL NEARING 10KFT INDICATE NW FLOW AREAS EAST OF MARQUETTE WILL CONTINUE TO SEE LIGHT AND MAYBE MODERATE SNOW ACCUMS AND CONTINUING BLOWING SNOW. HEAVIER SNOW LIKELY OCCURS OVERNIGHT MONDAY NIGHT THROUGH EARLY TUESDAY MORNING WHEN DIURNAL DISRUPTION IS MINIMAL AND WHEN LOW-LEVEL CONVERGENCE IS STRONGEST. POSSIBLE THAT MORE ADVISORIES MAY BE NEEDED MONDAY NIGHT THROUGH TUESDAY MORNING IN AREAS THAT ARE CURRENTLY IN A HEADLINE. SFC-H85 FLOW BECOMES INCREASINGLY ANTICYCLONIC TUESDAY WHICH OFFSETS SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS STAY AOB -15C THROUGH 18Z TUESDAY. GFS SOUNDINGS SHOW INVERSION FALLING BLO 5KFT OVR WEST AFT 12Z AND TO AROUND 5KFT FOR AREAS OVR EASTERN CWA. NO ADDITIONAL DEEPER MOISTURE AND CYCLONIC FLOW AT A MINIMUM SHOULD COMBINE WITH HIGHER EARLY APRIL SUN ANGLE/BLYR HEATING TO CONSIDERABLY DISRUPT LAKE EFFECT BY TUESDAY AFTN. GFS/GEM-NH SLIGHTLY LOWER WITH HEIGHTS AND COLDER AT H85 FARTHER WEST TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. RESULT IS AT LEAST ISOLD LK EFFECT CONTINUING OVER FAR EASTERN CWA. ECMWF MORE PROGRESSIVE WITH HEIGHTS AND KEEPS COLDER AIR ON THE MOVE LEADING TO LESS OF CHANCE OF LK EFFECT INTO WEDNESDAY. SOME HINT OF ANOTHER WEAKER TROUGH UPSTREAM THAT WILL HAVE TO DROP ACROSS THE UPPER LAKES AS LARGER TROUGH MOVES TO EAST. WILL HEDGE FORECAST TOWARD GFS/GEM-NH IDEA. SHORTWAVE RIDGING SLIDES ACROSS AREA FOR WEDNESDAY. LINGERING LK EFFECT CLOUDS/FLURRIES IN THE MORNING EAST...BUT THIS SHOULD BREAK UP IN AFTN WITH ARRIVAL OF SFC-H925 RIDGE. MAY SEE INCREASING HIGH CLOUDS OVER WEST BY LATE AFTN. OTHERWISE...A WARMER DAY SHAPING UP WITH LIGHT WINDS/LAKE BREEZES. MIXING TO H9-H85 SUPPORTS MAX TEMPS AS WARM AS LOWER 40S IN THE WEST AND STILL ABOVE THE FREEZING MARK ELSEWHERE. HIGH CLOUDS SPILLING IN LATE ON WEDNESDAY ARE IN ADVANCE OF SHORTWAVE TROUGH TRACKING ACROSS NORTHERN MANITOBA AND NORTHERN ONTARIO. MODELS STILL AT ODDS HOW QUICKLY THIS SYSTEM MOVES THROUGH WEDNESDAY NIGHT AND THURSDAY. 00Z GFS WAS SLOWER BUT 06Z LOOKS MORE LIKE ECMWF. GEM-NH WRAPPED UP AND SLOWER. HEIGHT FALLS AND H7-H5 Q-VECTOR CONVERGENCE FOCUS MOST PRECIPITATION WELL TO NORTH OF LK SUPERIOR. SFC-H85 FRONT/1000-850MB MOISTURE CONVERGENCE SWINGING ACROSS LK SUPERIOR AND UPR MICHIGAN...ALONG WITH RIBBON OF HIGHER H85-H7 MOISTURE...H85 MOISTURE/TEMPERATURE ADVECTION AND STEEPER H7-H5 LAPSE RATES AOA 6.5C/KM NOSING IN FROM WEST ADD UP TO BRIEF PERIOD OF SCATTERED PRECIPITATION AS FRONT WORKS THROUGH. IF TIMING IS LIKE ECMWF...THEN BETTER CHANCES WILL BE IN THE NORTH. IF TIMING ENDS UP SLOWER...THEN MORE AREAS SEE CHANCES AS HEATING OF THE DAY COMBINES WITH THE FORCING. EVEN WITH SLOWER IDEA...MOST PRECIP SHOULD BE OUT OF AREA BY MID AFTN. PTYPE ALSO DEPENDS ON TIMING AS A LATER ARRIVAL WOULD BRING RAIN POTENTIAL INTO MIX. FOR NOW...LOOKS LIKE MOSTLY SNOW AS SOUNDINGS INDICATE WET BULB FALLS BLO ZERO EXCEPT FOR FAR LOWEST REACHES OF BLYR. ONCE FRONT MOVES THROUGH QUIET WEATHER EXPECTED THROUGH FRIDAY AS HIGH PRESSURE DRIFTS ACROSS. GFS A FEW DEGREES COLDER AT H85 ON FRIDAY COMPARED TO ECMWF AND THUS HAS MORE IN WAY OF LAKE EFFECT CLOUDS. SYSTEM FOR NEXT WEEKEND STILL SHOWING UP...BUT THERE REMAIN SOME BIG QUESTIONS. UPPER LAKES REMAINS ON SOUTHERN EDGE OF STRONGER JET STREAM RIDING ALONG SOUTHERN TIER OF CANADA...WHICH WILL HELP ENHANCE PRECIPITATION ALONG SFC-H85 BAROCLINIC ZONE. WHERE THAT ZONE IS LOCATED IS UNCERTAIN. AS MID-LEVEL FLOW BECOMES MORE WESTERLY... SHORTWAVE TROUGH AND SFC-H85 LOWS MOVE FROM ROCKIES ACROSS THE NORTHERN PLAINS INTO WESTERN GREAT LAKES. OPERATIONAL MODELS FROM LAST NIGHT AND NAEFS ENSEMBLES INDICATED SLOWER ARRIVAL TO PRECIPITATION NOT IMPACTING MUCH OF UPR MICHIGAN UNTIL SATURDAY NIGHT. OF COURSE THE 12Z MODELS HAVE TRENDED QUICKER AGAIN. ECMWF IS A LOT QUICKER...BRINGING QPF OVER MOST OF UPR MICHIGAN BY 12Z SATURDAY...AND BASED ON 1000-500MB THICKNESS/H85 TEMPS IS SHOWING BETTER SHOT AT MIXED PRECIPITATION. KIND OF SEEMS LIKE ECMWF IS SHOWING TWO SEPARATE WAVES OF QPF AND THAT IS WHY IT APPEARS MUCH FASTER WITH QPF ARRIVAL. POOR RUN-TO-RUN CONSISTENCY CONTINUES WITH THE SYSTEM. UNTIL CONSISTENCY IMPROVES WILL KEEP WITH CONSENSUS OF MODELS FOR THIS SYSTEM FOR POPS. ENOUGH OF A SIGNAL FROM MODELS OVER LAST COUPLE DAYS TO GO WITH RAIN AND SNOW FOR PTYPE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 136 PM EDT SUN MAR 31 2013 DAYTIME HEATING AND DEVELOPMENT OF MIXED LAYER SHOULD GENERALLY RESULT IN VFR CLOUD BASES THIS AFTN AT KIWD/KCMX/KSAW. HOWEVER... WITH KCMX CLOSER TO SFC LOW TRACKING ACROSS NRN LAKE SUPERIOR AND ASSOCIATED LOW-LEVEL MOISTURE WRAPPING AROUND IT...CIGS WILL DROP TO MVFR AT TIMES THERE. EXPECT OCNL -SHSN WHICH WILL REDUCE VIS TO MVFR AT TIMES...PERHAPS VERY BRIEF IFR. WNW WINDS WILL BE GUSTY THRU THE AFTN...ESPECIALLY AT THE MORE EXPOSED KCMX WHERE WIND GUSTS UPWARDS OF 35KT SHOULD BE COMMON. WITH NOCTURNAL COOLING AND THE ARRIVAL OF SOME DEEPER MOISTURE...EXPECT MVFR CONDITIONS WITH -SHSN TONIGHT AT ALL 3 SITES AS THE GUSTY NW WINDS CONTINUE TO DRAW COLDER AIR INTO THE UPPER LAKES. MAY SEE SOME VERY BRIEF PERIODS OF IFR VIS AT KIWD AND KCMX. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 451 PM EDT SUN MAR 31 2013 STRONG NORTH TO NORTHWEST GALES TO 45 KTS INTO EARLY THIS EVENING AS COLD FRONT CROSSES LK SUPERIOR. STRONGEST WINDS OCCUR THROUGH LATE EVENING IN CORRIDOR FROM CNTRL LK SUPERIOR BUOY TO STANNARD ROCK AND ACROSS REST OF EASTERN LK SUPERIOR. GALES CONTINUE THROUGH MONDAY AND MONDAY NIGHT OVER SAME AREAS...BUT NOT QUITE AS STRONG. WINDS DIMINISH TO LESS THAN 25 KTS BY WEDNESDAY MORNING AS BRIEF RIDGING MOVES ACROSS. STRONGER SOUTHWEST WINDS TO 30 KTS THEN EXPECTED WEDNESDAY NIGHT AND THURSDAY MORNING AS LOW PRESSURE CROSSES NORTHERN ONTARIO AND DRAGS COLD FRONT ACROSS LK SUPERIOR. NORTHWEST WINDS TO 25 KTS DEVELOP BEHIND THE FRONT INTO NEXT WEEKEND. THE STRONG WINDS WILL DRAW MUCH COLDER AIR INTO THE UPPER LAKES EARLY THIS WEEK RESULTING IN FREEZING SPRAY THROUGH TUESDAY NIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND ADVISORY UNTIL 9 PM EDT THIS EVENING FOR MIZ001. WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR MIZ006-007-085. LAKE SUPERIOR... GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251-266-267. GALE WARNING UNTIL 6 PM EDT MONDAY FOR LSZ244-245-264-265. GALE WARNING UNTIL 5 PM EDT MONDAY FOR LSZ249. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
339 PM EDT SUN MAR 31 2013 .SHORT TERM...THROUGH TONIGHT DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES SENT A WEAK TROUGH/COLD FRONTAL BOUNDARY THROUGH THE AREA THIS MORNING WITH LITTLE IN THE WAY OF PRECIP ASSOCIATED WITH IT. IMPRESSIVE DRY SLOT BEHIND THE TROUGH WITHIN A REGION OF DEEP MIXING HAS CLEARED OUT MOST OF THE CLOUDS ALLOWING TEMPS TO SPIKE INTO THE MID 50S. THE DEEP MIXING HAS ALSO PRODUCED GUSTS TO AROUND 20 KNOTS THIS AFTERNOON. A STRONGER TROUGH/FRONT WILL GET SENT THROUGH THE REGION THIS EVENING. MODELS INDICATE STEEP LOW LEVEL LAPSE RATES AND CAPE VALUES BETWEEN 50-100 J/KG WITH A NARROW BAND OF THETA E JUST AHEAD OF THE TROUGH. THEY ALSO SHOW FAIRLY LOW PWATS TIED IN THE LOW LEVELS BRIEFLY SPIKING WITH THE THETA E AXIS BUT DRYING OUT RAPIDLY BEHIND THE TROUGH. THE HRRR AND HIRES WRF BOTH SHOW A PERIOD OF SHOWERS...RAIN BECOMING A MIX OF RAIN AND SNOW...BETWEEN 00Z AND 06Z WITH POSSIBLE FLURRIES OR LIGHT SNOW SHOWERS AFTER THAT. AN AREA OF PRECIP IS CURRENTLY SHOWING UP ON REGIONAL RADAR WITHIN THE TROUGH SO BESIDES FINE TUNING SOME TIMING ISSUES...SEE NO REASONS TO CHANGE MUCH WITH THE OVERNIGHT POPS/WX. WITH THE POSSIBLE CONVECTIVE NATURE OF THE PRECIP AND LONGER DURATION...WILL LEAVE A FEW TENTHS OF SNOW ACCUMULATIONS TO THE NORTH. WINDS WILL STAY ELEVATED OVERNIGHT WHICH WOULD TYPICALLY LEAD TOWARD WARMER MIN TEMPS BUT CAA BEHIND THE TROUGH WILL DROP 850MB TEMPS FROM +1C TO -11C OVERNIGHT. DEWPOINTS UPSTREAM IN THE TEENS WILL TRY TO WORK THEIR WAY INTO THE SAGINAW VALLEY AS WELL SO WE WILL STILL COOL OFF QUITE A BIT TONIGHT. && .LONG TERM... MONDAY THROUGH NEXT SUNDAY POLAR AIR NOW INFILTRATING THE UPPER MS VALLEY WILL BE OVER THE GREAT LAKES REGION BY MONDAY MORNING. THIS AIRMASS IS ASSOCIATED WITH A POLAR VORTEX NOW LOCATED OVER NRN ONTARIO. THIS UPPER LOW IS FORECAST TO DEEPEN AS IT TRACKS NORTHEAST OF LAKE HURON AND INTO QUEBEC ON MONDAY AND WILL REMAIN RATHER PROGRESSIVE...LIFTING INTO NEWFOUNDLAND BY MIDWEEK. BY 12Z MON...850MB TEMPS ARE STILL FORECAST TO PLUNGE TO -12 TO -14C OVER SE MI. WEAK MID LEVEL IMPULSES TRACKING INTO THE REGION TUES/TUES NIGHT WILL HOLD SOME DEGREE OF MID LEVEL TROUGHING OVER THE GREAT LAKES...WITH SE MI REMAINING FIRMLY WITHIN THE LOW LEVEL THERMAL TROUGH. DESPITE SOME INTERVALS OF SUN AND MIXING HEIGHTS EXTENDING UP TO 800MB...THE DEPTH OF COLD AIR WILL REMAIN SUPPORTIVE OF DAYTIME HIGHS MON AND TUES MAINLY IN THE 30S. NIGHTTIME MINS ARE EXPECTED TO DROP OFF INTO THE 20S /POSSIBLY SOME TEENS IF THE BOUNDARY LAYER CAN DECOUPLE/. THESE TEMPS ARE A GOOD 10 TO 15 DEGREES BELOW SEASONAL AVERAGES. W-NW WINDS WILL BE QUITE GUSTY ON MONDAY AS DEEPENING SFC LOW PRESSURE OVER QUEBEC SUSTAINS A TIGHT LOW LEVEL GRADIENT OVER THE REGION. SOME GUSTINESS TO THE WINDS IS LIKELY TO HOLD THROUGH MUCH OF TUESDAY AS THE LAKE AGGREGATE MAINTAINS A HEALTHY GRADIENT OVER SRN LOWER MI. THIS WILL PUT WIND CHILL READINGS IN THE TEENS AND 20S MON AND TUES. THE STEEP LOW LEVEL LAPSE RATES COURTESY OF THE COLD AIR WILL ALLOW A DIURNAL ENHANCEMENT TO THE CLOUDS MON AND TUES AFTERNOON. THE CORE OF THE MID LEVEL COLD POOL WILL HOWEVER TRACK TO THE NORTHEAST OF THE FORECAST AREA...THUS KEEPING CONVECTIVE CLOUD DEPTHS RATHER SHALLOW UNDER A MID LEVEL INVERSION. THIS ALONG WITH SUBSTANTIAL LOW LEVEL DRY AIR ADVECTION WILL SUPPORT JUST SCATTERED SNOW SHOWERS ON MONDAY. THE 12Z MODEL SUITE DO SHOW A MID LEVEL IMPULSE /NOW LOCATED OVER FAR NORTHERN CANADA/ DIVING INTO THE WESTERN GREAT LAKES LATE TUES. THE CURRENT MODEL SUITE SUGGEST THIS FEATURE WILL ARRIVE INTO SE MI TOWARD THE END OF THE DIURNAL CYCLE...WHICH SUPPORTS HOLDING ONTO THE DRY FORECAST AT THIS TIME. A SPLIT FLOW PATTERN IS FORECAST ACROSS NORTH AMERICA BY MID-LATE NEXT WEEK...WITH A FAST MOVING NORTHERN STREAM WAVE EXPECTED TO BRING A COLD FRONT INTO SRN MI IN THE THURS NIGHT/FRIDAY TIME FRAME. STEADY WARM AIR ADVECTION WILL ALLOW TEMPS TO RISE BACK UP INTO THE 50S ON THURSDAY PRIOR TO THE COLD FRONT PASSAGE. WHILE THE MEDIUM RANGE MODEL SUITE ARE IN GOOD AGREEMENT IN SHOWING A STRONG LOWER TROPOSPHERIC BAROCLINIC ZONE SETTING UP ACROSS THE NRN PLAINS AND GREAT LAKES REGION BY NEXT WEEKEND...THERE IS CONSIDERABLE DIFFERENCES WITH RESPECT TO THE TIMING AND AMPLITUDE OF MID LEVEL SHORT WAVE ENERGY EMANATING FROM THE PACIFIC AND TRACKING ALONG THE BAROCLINIC ZONE. LARGE SPREAD AMONG ENSEMBLE MEMBERS ADDS TO THE UNCERTAINTY. THERE IS HOWEVER ENOUGH CONFIDENCE TO CARRY A CHANCE OF PRECIP NEXT WEEKEND. && .MARINE... DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES WILL DROP THE SECOND OF TWO SURFACE TROUGHS THROUGH THE GREAT LAKES THIS EVENING...USHERING A MUCH COLDER AIRMASS INTO THE REGION. STRONG WESTERLY WINDS WILL VEER TO THE NORTHWEST BEHIND THIS TROUGH AND INCREASE WITH A TIGHTENING PRESSURE GRADIENT...ESPECIALLY OVER THE NORTHERN HALF OF LAKE HURON OVERNIGHT. A GALE WARNING HAS BEEN ISSUED FOR THE OPEN WATERS OF NORTHERN LAKE HURON WITH SMALL CRAFT ADVISORIES FOR ALL NEARSHORE WATERS OF LAKE HURON. WINDS WILL REMAIN ELEVATED THROUGH MONDAY NIGHT. && .AVIATION...ISSUED 137 PM EDT SUN MAR 31 2013 //DISCUSSION... LINGERING MVFR CIGS WILL LIFT TO VFR AS MIXING INCREASES THIS AFTERNOON. THE DEEP MIXING WILL ALLOWS WINDS TO GUST UP 25 KNOTS INTO THIS EVENING. THE SECOND COLD FRONT OF THE DAY WILL DROP THROUGH SE MI LATE THIS EVENING VEERING WINDS TO NW AND POSSIBLY PRODUCING SOME LIGHT RAIN SHOWERS THIS EVENING OR A RAIN/SNOW MIX OVERNIGHT...WHILE DROPPING CIGS BACK TO MVFR. COVERAGE AND CONFIDENCE OF PRECIPITATION TOO LOW TO INCLUDE IN THE TAFS ATTM. THE STRONG COLD FRONT WILL ALLOW WINDS TO STAY ELEVATED THROUGH THE NIGHT. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE THAT CEILINGS WILL FALL BELOW 5000 FEET THIS EVENING THROUGH MONDAY MORNING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...FROM 10 PM SUNDAY TO 10 PM MONDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...FROM 10 PM SUNDAY TO 8 AM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT HURON...FROM 4 AM MONDAY TO 8 AM TUESDAY. SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 4 AM MONDAY TO 10 PM MONDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DRK LONG TERM....SC MARINE.......DRK AVIATION.....DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
137 PM EDT SUN MAR 31 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 544 AM EDT SUN MAR 31 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR TROF OVER CENTRAL NAMERICA DOWNSTREAM OF RDG OFF THE W COAST AS FAIRLY VIGOROUS SHRTWV NEAR LK WINNIPEG IS DIGGING SEWD TOWARD NW MN. SHRTWV RESPONSIBLE FOR PCPN ON SAT IS NOW OVER LOWER MI...AND ARRIVAL OF MUCH DRIER AIR SHOWN ON THE 00Z INL RAOB IS TENDING TO BREAK UP LINGERING FOG/LO CLD AT LEAST OVER THE WRN TIER DESPITE UPSLOPE LLVL WNW FLOW IN WAKE OF SFC LO PRES TROF ASSOCIATED WITH THAT DISTURBANCE. SINCE THE INCOMING AIRMASS WITH 00Z H85 TEMP OF -2C AT INL IS NOT SUFFICIENTLY COLD FOR LES EITHER...THERE IS NO PCPN. LOOKING UPSTREAM...AN AREA OF MID CLD IS PRESENT OVER NW MN/ NW ONTARIO AHEAD OF THE LK WINNIPEG SHRTWV AND ASSOCIATED COLD FNT PLUNGING SSEWD. PCPN AHEAD OF THIS BNDRY IS ABSENT GIVEN THE DRYNESS OF THE INL/YPL RAOBS DESPITE SOME RATHER SHARP DVPA/H85-5 QVECTOR CNVGC...BUT SOME PLACES SHOW SN IMMEDIATELY BEHIND THE FROPA. ALTHOUGH H85 TEMPS FALL SHARPLY BEHIND THE COLD FNT TO -14C AT THE PAS IN MANITOBA NEAR LK WINNIPEG...THE 00Z RAOB FM THAT SITE SHOWS A FAIRLY DRY AIRMASS/INVERTED V T-TD PROFILE BLO H85. BUT JUST TO THE E WITHIN THE COLDER AIRMASS...MORE CLDS/-SN ARE EVIDENT IN FAR NW ONTARIO. MAIN FCST CONCERNS THRU TNGT ARE SHSN POTENTIAL AND WINDS ASSOCIATED WITH AND FOLLOWING SHRTWV DIGGING TOWARD THE UPR GRT LKS/ATTENDANT COLD FROPA. EASTER SUN...AS LLVL DRY AIR MOVES IN EARLY THIS MRNG...EXPECT TREND TOWARD FOG/ST TO BREAK UP W-E. BUT ARRIVAL OF COLD FNT OVER THE NW BY LATE MRNG WL RESULT IN MORE CLDS AND SHSN IN THIS AREA AS AREA OF MSTR IN NW MN/ADJOINING ONTARIO SWINGS OVHD. SINCE THE MOST IMPRESSIVE DPVA/H85-5 QVECTOR CNVGC IS PROGGED TO SWING BY TO THE N OF UPR MI...EXPECT ACCOMPANYING SHSN TO BE RELATIVELY MODEST EVEN IF THERE IS SOME ENHANCEMENT OVER MAINLY THE HIER TERRAIN OF THE NW. AS THE FNT SWINGS THRU THE REST OF THE CWA EARLY THIS AFTN...DEEP LYR QVECTOR DVGC/MID LVL DRYING SHOULD LIMIT PCPN TO SCT -SHSN THAT WL BE AT LEAST MIXED WITH RA OVER THE SCNTRL AS TEMPS RISE AOA 40 IN THOSE DOWNSLOPE AREAS. BEST CHC FOR MORE NMRS SHSN WL BE OVER THE NRN TIER CLOSER TO SHRTWV DYNAMICS. EVEN WITH STRENGTHENING NW FLOW/CAD BEHIND THE FROPA THAT DROPS H85 TEMPS TO NEAR -14C BY 00Z MON...ARRIVAL OF DRIER AIR MORE REPRESENTED BY THE 00Z YQD RAOB ALONG WITH DAYTIME HEATING/INVERTED V LOOK TO GFS FCST SDNGS FOR CMX SHOULD TEND TO LIMIT THE SHSN INTENSITY IN THE WAKE OF THE FROPA. AS FOR THE WINDS...THE PREFERRED GFS SHOWS A FAIRLY SHARP PRES RISE CENTER FOLLOWING THE FROPA AND REACHING NCENTRL LK SUP BY 00Z WITH ISALLOBARIC WIND FAVORABLY ALIGNED WITH THE NW GRADIENT FLOW. SINCE SEVERAL MODELS SHOW H925 WINDS UP TO 40 KTS STREAMING INTO THE ERN ZNS AT 00Z WITH CONSIDERABLE CAD/DESTABILIZATION AS WELL AS THE FAVORABLE ALIGNMENT OF THE ISALLOBARIC WIND TO THE GRADIENT FLOW... EXPECT ADVY LVL GUSTS TO 45 MPH IN THE EXPOSED LK SUP SHORELINE E OF MQT AFT 21Z. AS THE CLOSED LO OVER SE CANADA MOVES TO THE E TNGT...SHARP CYC NW FLOW IS PROGGED TO VEER A BIT MORE TOWARD THE NNW...WHICH MIGHT ALLOW DEEPER MSTR NOW OVER NW ONTARIO TO INFILTRATE THE UPR LKS AS SHOWN BY NMRS MODEL H7 RH PROGS. IN COMBINATION WITH H85 TEMPS FALLING AS LO AS -17C TO -18C AND NOCTURNAL COOLING THAT WOULD FAVOR MORE TYPICAL LES BANDING...MAINTAINED THE FLAVOR OF PREVIOUS FCST WITH LES POPS INCRSG TO CATEGORICAL IN THE SN BELTS FAVORED BY THE EXPECTED FLOW. NEARLY UNIDIRECTIONAL NATURE OF THE SFC-H85 FLOW IN THE WELL MIXED CONVECTIVE LYR MIGHT ALSO FAVOR HEAVIER SN BANDS. SINCE THE ERN ZNS WL BE CLOSER TO THE DEPARTING LO...HAVE A BETTER OPPORTUNITY TO BE IMPACTED BY THE DEEPER MSTR...AND WL SEE ADVY LVL WIND GUSTS AT LEAST THRU 06Z BEFORE THE PRES RISE CENTER SHIFTS FARTHER E AND WEAKENS THE ISALLOBARIC WIND...OPTED TO ISSUE A WINTER WX ADVY FOR ALGER/NRN SCHOOLCRAFT/LUCE COUNTIES FOR THE COMBINATION OF STRONG WINDS...LES...AND BLSN. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 544 AM EDT SUN MAR 31 2013 AFTER A SEVERAL DAY STRETCH OF NEAR NORMAL EARLY SPRING WEATHER...IT LOOKS LIKE A RETURN TO FEBRUARY LIKE WEATHER IS ON TAP FOR THE EARLY PART OF THE WORK WEEK. COLD ADVECTION WILL CONTINUE ON MONDAY ON THE BACKSIDE OF UPPER TROUGH PUSHING THROUGH THE UPPER LAKES. 85H TEMPS FALL DOWN TO AROUND -18C ACROSS LAKE SUPERIOR DURING THE DAY ON MONDAY. UNUSUAL TO BE DEALING WITH LAKE EFFECT IN EARLY APRIL BUT WITH LAKE TEMPS BETWEEN 1-2C...SUFFICIENT DELTA TS WILL BE IN PLACE FOR LAKE EFFECT SNOW IN NORTHWESTERLY WIND SNOW BELTS. THE CHALLENGE OF THE FCST IS THE EXTENT OF ACCUMULATIONS AND OVERALL IMPACTS OF THE SNOW. THE FACT THAT IT IS APRIL...FCST SOUNDINGS ARE SHOWING A LOW LEVEL INVERTED V SIGNATURE...THE TYPICAL DISRUPTION IN THE LAKE EFFECT PROCESS FROM DIURNAL HEATING THIS TIME OF YEAR...ALL LEND TO THE UNCERTAINTY IN THE FCST. AREAS MOSTLY LIKELY TO SEE MORE OF THE IMPACTS WILL BE ALGER AND LUCE COUNTIES AND WILL LET WINTER WEATHER ADVISORY EXTEND THROUGH MONDAY MORNING TO ACCOUNT FOR FALLING SNOW AND BLOWING SNOW...ESPECIALLY NEAR LAKE SUPERIOR. THE NEGATIVES LISTED ABOVE MAY THEN BECOME TOO MUCH FOR SIGNIFICANT IMPACTS DURING THE AFTERNOON MONDAY. AWAY FROM THIS AREA...EXPECT LAKE EFFECT SNOW SNOW SHOWERS TO PRODUCE SOME LIGHT ACCUMULATIONS ACROSS THE KEWEENAW AND WESTERN U.P. THE MOST NOTICEABLE THING ABOUT MONDAY WILL BE THE FACT THAT TEMPERATURES WILL ONLY CLIMB INTO THE LOWER TO MID 20S AND WITH GUSTY NORTHWEST WINDS IT WILL FEEL CONSIDERABLY COLDER. THERE COULD BE A SLIGHT UPTICK IN LAKE EFFECT SNOW MONDAY NIGHT ACROSS THE EAST WITH INVERSION HEIGHTS REMAINING AROUND 8KFT...TRAJECTORIES FAVORING A LITTLE MORE LOW LEVEL MOISTURE...AND TYPICAL NIGHTTIME INCREASE IN LAKE EFFECT THIS TIME OF YEAR. MAY NEED TO CONSIDER ANOTHER ADVISORY FOR ALGER AND LUCE COUNTIES AGAIN MONDAY NIGHT. ELSEWHERE...EXPECT LAKE EFFECT SNOW SHOWERS TO CONTINUE ACROSS THE WEST BUT ACCUMULATIONS SHOULD REMAIN RELATIVELY LIGHT. LAKE EFFECT PROCESS WINDS DOWN QUICKLY ON TUESDAY WITH INVERSION LOWERING SIGNIFICANTLY AND SURFACE RIDGING APPROACHING FROM THE WEST. TEMPERATURES WILL REMAIN WELL BELOW NORMAL...MORE LIKE MID FEBRUARY. RIDGE AXIS WILL MOVE ACROSS THE AREAM ON WEDNESDAY. WITH ABUNDANT SUNSHINE AND WARM ADVECTION COMMENCING ON THE BACK SIDE OF THE RIDGE TEMPS SHOULD REBOUND BACK ABOVE FREEZING TO WITHIN A FEW DEGREES OF NORMAL. NEXT TROUGH AND FRONT WILL CROSS THE AREA ON THURSDAY. NOT VERY MUCH MOISTURE TO WORK WITH SO ONLY EXPECT SOME LIGHT RAIN AND SNOW SHOWERS WITH ITS PASSAGE. ANOTHER DECENT COLD SHOT WILL KNOCK TEMPERATURES BACK BELOW NORMAL FOR FRIDAY. HAVENT LOOKED TOO MUCH AT NEXT WEEKENDS FORECAST BUT THERE APPEARS TO BE A TREND POINTING TOWARD A MORE SOUTHERN TRACK OF A STORM SYSTEM PUSHING THROUGH THE LOWER LAKES. WILL BE SOMETHING TO KEEP AN EYE ON AS THE WEEK PROGRESSES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 136 PM EDT SUN MAR 31 2013 DAYTIME HEATING AND DEVELOPMENT OF MIXED LAYER SHOULD GENERALLY RESULT IN VFR CLOUD BASES THIS AFTN AT KIWD/KCMX/KSAW. HOWEVER... WITH KCMX CLOSER TO SFC LOW TRACKING ACROSS NRN LAKE SUPERIOR AND ASSOCIATED LOW-LEVEL MOISTURE WRAPPING AROUND IT...CIGS WILL DROP TO MVFR AT TIMES THERE. EXPECT OCNL -SHSN WHICH WILL REDUCE VIS TO MVFR AT TIMES...PERHAPS VERY BRIEF IFR. WNW WINDS WILL BE GUSTY THRU THE AFTN...ESPECIALLY AT THE MORE EXPOSED KCMX WHERE WIND GUSTS UPWARDS OF 35KT SHOULD BE COMMON. WITH NOCTURNAL COOLING AND THE ARRIVAL OF SOME DEEPER MOISTURE...EXPECT MVFR CONDITIONS WITH -SHSN TONIGHT AT ALL 3 SITES AS THE GUSTY NW WINDS CONTINUE TO DRAW COLDER AIR INTO THE UPPER LAKES. MAY SEE SOME VERY BRIEF PERIODS OF IFR VIS AT KIWD AND KCMX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 544 AM EDT SUN MAR 31 2013 AS A STRONG DISTURBANCE MOVES OVER LK SUP TODAY...A DEEP LO PRES WILL TAKE SHAPE OVER SE CANADA AND CAUSE NW WIND TO INCREASE TO GALE FORCE OVER THE NCENTRAL AND E PORTIONS OF THE LAKE BY THIS AFTERNOON. THESE STRONG NW WINDS WILL CONTINUE TONIGHT AND DRAW MUCH COLDER AIR INTO THE UPPER LAKES. THE RESULT WILL BE FREEZING SPRAY. MAINTAINED GOING GALE WARNING FOR MOST OF THE NCENTRAL AND E HALF. NORTHWEST GALES WILL CONTINUE ACROSS THE EASTERN HALF OF LAKE SUPERIOR INTO TUESDAY BEFORE RIDGING BUILDS ACROSS THE LAKE WITH WINDS DIMINISHING TO LESS THAN 20 KNOTS. WINDS SHOULD REMAIN BELOW 20 KNOTS INTO THURSDAY BEFORE THE NEXT QUICK MOVING FRONT MOVES ACROSS THE UPPER GREAT LAKES. NORTHWEST WINDS TO 30 KNOTS WILL BE POSSIBLE BEHIND THE FRONT TO END THE WORK WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 2 PM EDT MONDAY FOR MIZ006-007-085. LAKE SUPERIOR... GALE WARNING UNTIL 8 PM EDT TUESDAY FOR LSZ264>267. GALE WARNING UNTIL 6 PM EDT MONDAY FOR LSZ244-245-249>251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...MZ AVIATION...ROLFSON MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
127 PM EDT SUN MAR 31 2013 .SYNOPSIS... ISSUED AT 330 AM EDT SUN MAR 31 2013 TEMPERATURES WILL AVERAGE NEAR NORMAL TODAY BEFORE ANOTHER ROUND OF UNSEASONABLY COLD AIR MOVES IN TONIGHT THROUGH TUESDAY. TEMPERATURES WILL AVERAGE TEN TO FIFTEEN DEGREES BELOW NORMAL MONDAY THROUGH TUESDAY WITH A FEW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES FROM THE EARLY MORNING HOURS MONDAY THROUGH TUESDAY MORNING. TEMPERATURES WILL MODERATE MID TO LATE WEEK AND RETURN TO NEAR NORMAL BY THURSDAY AND FRIDAY. DRY WEATHER IS ANTICIPATED MID TO LATE WEEK AS HIGH PRESSURE BUILDS IN. && .SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON) ISSUED AT 1000 AM EDT SUN MAR 31 2013 LOOKING AT A FAIR AMOUNT OF EARLY AFTERNOON SUNSHINE AS LOW LEVEL MOISTURE MIXES OUT THIS MORNING. STILL LOOKING AT EARLY AFTERNOON TEMPS RANDING FROM THE UPPER 40S AT THE COAST TO MID 50S INLAND. ALSO LIKE HI RES GUIDANCE SUGGESTING A COUPLE BANDS OF LIGHT SHRA / SPRINKLES SPREADING WEST TO EAST AFTER 5PM. SHRA ACTIVITY WILL BE ALONG AND AHEAD OF LEADING EDGE OF ARCTIC AIR. EXPECT WESTERLY WIND GUSTS TO 30 MPH INLAND THIS AFTERNOON WITH INITAL CAA AND MIXING. INITIALLY...STABLE TEMPERATURE STRATIFICATION OVER THE LAKE WILL INHIBIT GUSTINESS. A SECOND ROUND OF WIND GUSTS TO 35 MPH WILL AFFECT ALL AREAS AS THE ARCTIC AIR MOVES IN EARLY THIS EVENING. SCATTERED WNW FLOW LIGHT LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL DEVELOP VERY LATE TONIGHT AND CONTINUE MONDAY AS H8 TEMPS FALL TO -13 TO -15 C BY 12Z MON. HOWEVER WITH A VERY DRY AIRMASS ADVECTING IN AND LACK OF BETTER MOISTURE OR UPSTREAM RH THIS WILL NOT AMOUNT TO ANYTHING (TRACE AMOUNTS TO JUST A FEW TENTHS OF AN INCH OF SNOW FROM THE EARLY MORNING HOURS MONDAY THROUGH EARLY TUESDAY). ANY LINGERING FLURRIES EARLY TUESDAY SHOULD END WITH AN EVEN DRIER AIRMASS IN PLACE LATER ON TUESDAY AND AS H8 TEMPS BEGIN TO MODERATE A BIT BY TUESDAY AFTN. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 330 AM EDT SUN MAR 31 2013 AFTER THE EARLY WEEK COLD BLAST... IT LOOKS LIKE WINTER WILL LOOSEN ITS GRIP ON THE GREAT LAKES REGION. MEDIUM RANGE GUIDANCE IS STARTING TO SHOW SOME CONSISTENCY THAT THE TROUGHING WHICH HAS PERSISTED MOST OF MARCH OVER THE ERN U.S. WILL FINALLY LIFT OUT. FOR THE MID TO LATE WEEK PERIOD THE UPPER FLOW WILL BE ZONAL WHICH IMPLIES UNEVENTFUL WEATHER WITH TEMPERATURES MODERATING TO CLOSER TO NORMAL VALUES. HOWEVER THERE ARE SIGNS THAT AN UPPER RIDGE WILL BEGIN TO BUILD OVER THE REGION ABOUT A WEEK FROM NOW AS A DEEP LONGWAVE TROUGH EVOLVES OVER THE WRN UNITED STATES. THIS IMPLIES THAT ABOVE NORMAL TEMPERATURES WILL DEVELOP BEYOND DAY 7. SFC HIGH PRESSURE WEDNESDAY AND THURSDAY OUGHT TO LEAD TO ABUNDANT SUNSHINE ALTHOUGH RATHER CHILLY NIGHTTIME TEMPERATURES. A WEAK SFC BOUNDARY DOES DROP SOUTH THROUGH THE REGION ON THURSDAY NIGHT BUT NO PRECIP IS EXPECTED AS THERE IS LITTLE MOISTURE TO WORK WITH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 126 PM EDT SUN MAR 31 2013 THE BACK EDGE OF THE STRATOCU SHOULD MOVE ONSHORE NEAR KMKG BY 19Z OR SO AND THEN MOVE EAST TO KGRR BY 20Z OR SHORTLY THERE AFTER. THINKING THAT KLAN WILL BE SCT AT 18Z AND REMAIN THAT WAY. HOWEVER...IT/S POSSIBLE THAT KLAN COULD DEVELOP A BKN MVFR CIG FOR A COUPLE OF HOURS IN THE 19-21Z TIME FRAME IF THE CLOUDS NEAR KGRR CAN MOVE EAST. VIS LOOP SHOWS THOSE CLOUDS DECAYING ON THE ERN EDGE AND SO WE LEFT THE CLOUDS SCTD AT KLAN THIS AFTERNOON. WINDS WILL INCREASE FROM THE NW THIS EVENING AS A COLD FRONT MOVES THROUGH. SHSN MAY DEVELOP OVERNIGHT ALONG WITH MVFR CIGS. && .MARINE... ISSUED AT 1000 AM EDT SUN MAR 31 2013 BASED ON LATEST 3KM HRRR GUIDANCE...SMALL CRAFT CONDITIONS WILL DEVELOP AROUND 00Z (8PM EDT) THIS EVENING...A BIT EARLIER THAN FIRST EXPECTED. WIND GUSTS AROUND 30 KTS WITH SEAS BUILDING 5 TO 7 FEET STILL LOOKING GOOD. VISIBILITY WILL OCCASIONALLY DROP BELOW 1 MILE IN LAKE EFFECT SNOW SHOWERS OVERNIGHT THROUGH MONDAY. HIGH PRESSURE WILL BRING FAIR WEATHER AND LIGHT WINDS FOR LATE TUESDAY THROUGH THURSDAY. && .HYDROLOGY... ISSUED AT 330 AM EDT SUN MAR 31 2013 NO HYDRO ISSUES EXPECTED. RIVERS ARE ALL WELL BELOW ACTION STAGE AND WILL REMAIN SO THROUGH THE WEEK. THE OVERALL WEATHER PATTERN THIS WEEK WILL BE CONDUCIVE TO A GRADUAL MELTING AND RUNOFF OF REMAINING SNOW COVER. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT TUESDAY FOR LMZ844>849. && $$ SYNOPSIS...LAURENS SHORT TERM...COBB LONG TERM...MEADE AVIATION...93 HYDROLOGY...LAURENS MARINE...COBB
AREA FORECAST DISCUSSION
NWS JACKSON MS
359 PM CDT SUN MAR 31 2013 .DISCUSSION... TODAY THROUGH EARLY WEDNESDAY WEAKENING SQUALL LINE PUSHING THROUGH THE REGION TO THE SOUTHEAST TONIGHT WITH QUIETER WEATHER MONDAY AND TUESDAY BEFORE MORE RAIN FOR MIDDLE TO LATE WEEK. SEVERAL REPORTS OF TREES AND POWERLINES DOWN HAVE COME IN FROM NORTHEAST LA AND WEST MS AS THE ONCE STRONGER SQUALL LINE MOVED THROUGH. HOWEVER, AN OVERALL WEAKENING TREND OVER THE PAST HOUR AS BEEN OBSERVED AS IT ENCOUNTERS A LESS FAVORABLE AIRMASS TO THE EAST. WARMING CLOUD TOPS VIA IR SAT AND WEAKENING REFLECTIVITY GRADIENT FURTHER SUGGEST MCS IS BECOMING COLD POOL DOMINATED WHILE BEING FARTHER REMOVED FROM LARGER SCALE FORCING. HAVE CANCELED PORTIONS OF THE SEVERE TSTORM WATCH TO THE WEST OF THE CURRENT LINE. THE BEST ENVIRONMENT FOR MARGINAL STRONG TO BRIEFLY SEVERE STORMS IS ACROSS FAR S/SE AREAS WHERE RAP OUTPUT SUGGEST 500-1000 J/KG SBCAPE AND ~30 KT ORGANIZATIONAL DEEP LAYER SHEAR. HOWEVER, FEEL THE COLD POOL DOMINATION AND LACK OF FORCING SHOULD KEEP MOST STORMS IN CHECK FROM BEING SEVERE ACROSS THE REMAINDER OF THE AREA. BUT ONE OR TWO STORMS COULD BRIEFLY BECOME SEVERE ACROSS THIS AREA TROUGH EARLY EVENING. AS THE TSTORM LINE AND CLOUDS CLEAR TONIGHT FROM THE NORTH, DEVELOPMENT OF FOG WILL BE LIKELY ACROSS A MAJORITY OF THE REGION. SOME ISOLATED LOCATIONS OF DENSE FOG ARE PSBL TONIGHT THROUGH 8AM TOMORROW MRNG. FOG WILL DISSIPATE THROUGH 9AM AS MIXING STEADILY INCREASES. THE WEAKENING TSTORM LINE WAS INITIATED ON A LOW-LVL FRONTAL BOUNDARY AND A NRN STREAM H5 S/WV TROUGH PIVOTING ACROSS THE LOWER PLAINS. THIS FRONTAL BOUNDARY WILL STALL ALONG THE I-10 TO HIGHWAY 84 CORRIDOR SECTOR OVERNIGHT AND MONDAY. ANOTHER QUICK MOVING IMPULSE IN THE NW FLOW MAY HELP SOME SHOWERS LINGER THROUGH THE EARLY MRNG HOURS ACROSS FAR SOUTHERN LOCATIONS. THIS BOUNDARY WILL SERVE AS A IMPETUS FOR A FEW SHOWERS AND THUNDERSTORMS MON AFTN ALSO AS DIURNALLY DRIVEN INSTABILITY BUILDS INVOF GREATEST SFC CONVERGENCE. MAV POPS CAME IN QUITE LOW DESPITE GFS HOLDING UP THE FRONT ACROSS THIS REGION. THE EC AND NAM ARE IN AGREEMENT OF DIURNALLY DRIVEN QPF ALSO. THEREFORE, BUMPED POPS UP ACROSS SRN TIER OVER MAV. FOR CNTRL AND NORTH AREAS HOWEVER, BUFR SOUNDINGS SUGGEST AMPLE SUN WITH TEMPS RISING INTO THE MID 70S AS SFC HIGH PRESSURE AXIS NOSES IN. THE SFC HIGH PRESSURE WILL ALSO AID IN A REINFORCING SHOT OF COOLER/DRIER AIR IN THE LOW LEVELS TUESDAY MRNG THAT WILL QUELL TEMPS FROM REACHING MONDAY`S LEVELS. MID AND HIGH LEVEL CLOUDS WILL BE ON THE INCREASE TUESDAY INTO TUESDAY NIGHT AS OUR NEXT SYSTEM TAKES SHAPE ACROSS THE INTER-MOUNTAIN WEST. A SUPPRESSED PACIFIC H5 S/WV TROUGH WILL SWING ACROSS THE FOUR CORNERS REGION LATE TUESDAY AND HELP SFC LOW CYCLOGENESIS ACROSS TEXAS. A DECENT PRESSURE GRADIENT APPEARS TO BE IN PLACE GOING INTO TUES NIGHT WITH SFC HIGH JUST OFF TO NORTH AND THE DEVELOPING SFC LOW. SMALL PERTURBATIONS/ IMPULSES IN THE H5 FLOW WILL MOVE OVER TOP THE ARKLAMISS LATE TUES INTO EARLY WEDS AIDING IN ISENTROPIC ASCENT. LIGHT SHOWER ACTIVITY WILL BE ON THE INCREASE LATE TUES NIGHT INTO WED MRNG FOR WESTERN AND CENTRAL ARKLAMISS AREAS. FOR FORECAST ELEMENTS...WINDS WERE BUMPED UP IN ASSOCIATION WITH THE TSTORM COMPLEX. MAV POPS WERE BUMPED DOWN DRAMATICALLY TONIGHT THEN SLIGHTLY UP FOR SOUTHERN AREAS DAY PERIOD MONDAY. FOG WAS ADDED TO THE OVRNGT PERIOD ALSO. MAV POPS WERE GENERALLY FOLLOWED TUESDAY NIGHT INTO WEDNESDAY. MAV TEMPS WERE DROPPED A TOUCH FOR NRN AREAS TOMORROW GIVEN BUFR SOUNDINGS AND MAX HEATING POTENTIAL. /ALLEN/ && .AVIATION...A LINE OF SHOWERS AND THUNDERSTORMS EXTENDS ACROSS THE CENTRAL PORTIONS OF THE AREA THIS AFTERNOON AND IS CURRENTLY BRINGING MVFR CONDITIONS TO GWO/HKS/JAN. THIS LINE OF STORMS WILL CONTINUE TO MOVE EAST AND AFFECT MEI/HBG AND GTR LATER THIS AFTERNOON INTO THE EARLY EVENING. VFR CONDITIONS ARE RETURNING TO GLH AS DRIER AIR MOVES OVER THE NORTHWESTERN PORTIONS OF THE AREA. THE SHOWERS AND THUNDERSTORM WILL MOVE TO THE EAST OF THE AREA EARLY THIS EVENING...BUT WILL STILL BE POSSIBLE AT HBG THROUGH MUCH OF THE NIGHT. IFR CONDITIONS ARE ONCE AGAIN POSSIBLE EARLY MONDAY OVER MOST SITES DUE TO STRATUS AND FOG. /15/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 54 78 49 69 / 27 14 4 20 MERIDIAN 53 77 45 72 / 32 13 4 12 VICKSBURG 54 78 51 68 / 25 14 3 31 HATTIESBURG 60 79 51 74 / 66 22 5 13 NATCHEZ 54 77 54 70 / 59 20 3 28 GREENVILLE 52 75 46 61 / 11 10 3 36 GREENWOOD 51 75 46 65 / 12 10 4 26 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ ALLEN/15
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
104 PM CDT SUN MAR 31 2013 .SHORT TERM...(EASTER SUNDAY) ISSUED AT 224 AM CDT SUN MAR 31 2013 FORECAST HAS CHANGED TODAY GIVEN CURRENT CONDITIONS AND LATEST SHORT RANGE MODEL GUIDANCE. SHORTWAVE ENERGY...EVIDENT ON LATEST WATER VAPOR IMAGERY...DROPPING SOUTHEAST FROM SOUTHERN NEBRASKA HAS LED TO A LARGE AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOPING ACROSS EASTERN KANSAS AND WEST CENTRAL MISSOURI. LATEST RUC AND HRRR SHOW THIS AREA OF RAIN SHOWERS/STORMS EXPANDING AS EAST/SOUTHEAST THIS MORNING ACROSS CENTRAL MISSOURI AND THE OZARKS...PERHAPS GRAZING EAST CENTRAL MISSOURI AND SOUTHWEST ILLINOIS. WILL FINE TUNE POPS BEFORE FORECAST ISSUANCE BASED ON THE VERY LATEST RADAR TRENDS. THERE WILL OBVIOUSLY BE A SLOWER CLEARING TREND TO THE CLOUDS THANKS TO THIS SHORTWAVE...AND FEEL IT PRUDENT TO SIDE WITH SLIGHTLY COOLER MAV GUIDANCE FOR HIGH TEMPERATURES. TO COMPLICATE THE FORECAST EVEN FURTHER...MUCH OF THE EXPLICIT AND HIGH RESOLUTION MODEL GUIDANCE DEPICT SOME ISOLATED SHOWERS DEVELOPING ALONG A PREFRONTAL TROF THIS AFTERNOON AND EVENING FROM CENTRAL ILLINOIS TOWARD THE ST. LOUIS METRO AREA. SO HAVE INCLUDED SOME LOW CHANCE/ISOLATED POPS FOR THIS AS WELL. CVKING && .LONG TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 224 AM CDT SUN MAR 31 2013 (TONIGHT AND MONDAY) ARCTIC COLD FRONT EXPECTED TO MOVE SOUTH ACROSS THE CWA TONIGHT WITH NORTH WIND AND COLD ADVECTION TAKING CONTROL OF THE WEATHER FOR THE EARLY PART OF THE WORK WEEK. LATEST GUIDANCE CONTINUES TO DEPICT A BAND OF LIGHT POST FRONTAL PRECIPITATION AFFECTING MAINLY NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS SUNDAY NIGHT. THIS PRECIPITATION SHOULD WEAKEN AS IT PROGRESSES SOUTH MONDAY MORNING TO THE I-70 CORRIDOR. MAINTAINED RAIN/SNOW MIX...BUT DONT EXPECT ANY ACCUMULATION DUE TO WARM AIR AND GROUND TEMPERATURES. HAVE SIDED WITH COOLER MET GUIDANCE FOR TEMPERATURES. (TUESDAY THROUGH SATURDAY) SLOW WARMING TREND EXPECTED WITH HIGH PRESSURE MOVING EAST OF THE AREA BY LATE IN THE WEEK. HAVE KEPT FORECAST DRY AS GUIDANCE KEEPS CUTOFF LOW TO THE SOUTH OF THE AREA THURSDAY. CVKING && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1242 PM CDT SUN MAR 31 2013 SCATTERED DIURNAL CUMULUS CLOUDS CAN BE EXEPCTED THIS AFTN. W-NWLY SFC WINDS WILL STRENGTHEN AND BECOME GUSTY THIS AFTN. THESE NWLY SFC WINDS WILL BECOME NLY TGT AFTER PASSAGE OF A COLD FRONT. A BAND OF POST FRONTAL LOW-MID LEVEL CLOUDS WILL ADVECT SWD THROUGH THE TAF SITES LATE TGT AND EARLY MON MRNG. THERE SHOULD BE A BRIEF PERIOD OF LIGHT SNOW IN UIN LATE TGT INTO EARLY MON MRNG AS MUCH COLDER AIR FILTERS INTO THE REGION BEHIND THE COLD FRONT. WILL KEEP ANY PRECIPITATION OUT OF THE REST OF THE TAF SITES FURTHER S AS IT LOOKS LIKE THIS WILL BE MAINLY JUST SPRINKLES OR FLURRIES. WILL ALSO KEEP THE CLOUD CEILING VFR AT COU AND THE ST LOUIS METRO AREA TAFS...ALTHOUGH THERE COULD BE A BRIEF PERIOD OF MVFR CIGS AROUND 09-15Z MON. MOST OF THIS CLOUD COVER SHOULD ADVECT S OF THE TAF SITES BY LATE MON MRNG AS A STRONG SFC RIDGE BUILDS SEWD INTO THE REGION. SPECIFICS FOR KSTL...JUST SCT CUMULUS CLOUDS THIS AFTN...THEN A BAND OF MAINLY VFR LOW-MID LEVEL CLOUDS WILL PASS SWD THROUGH STL BETWEEN 09-15Z MON. THERE COULD BE SPRINKLES OR FLURRIES FROM THESE CLOUDS BUT WILL KEEP THE STL TAF DRY FOR NOW. JUST SCT LOW LEVEL CLOUDS LINGERING INTO MON AFTN. NWLY SFC WIND SHOULD INCREASE SOME AND BECOME GUSTY LATER THIS AFTN...THEN WEAKEN THIS EVNG. THE NWLY SFC WIND WILLL BECOME NLY BY LATE TGT AFTER FROPA. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
525 PM EDT SUN MAR 31 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION FROM THE WEST TONIGHT...WITH A SECOND COLD FRONT MOVING OVER THE AREA MONDAY NIGHT. HIGH PRESSURE WILL FILL IN BEHIND THE SECOND FRONT USHERING IN COOLER THAN NORMAL TEMPERATURES THROUGH THURSDAY. ON FRIDAY A LOW DEVELOPS IN THE GULF AND MOVES TOWARDS THE SOUTH CAROLINA COAST. && .NEAR TERM /THROUGH MONDAY/... AS OF 515 PM EDT...THE LATEST HRRR MESOSCALE MODEL RUNS HAVE BEEN PERFORMING QUITE WELL IN DEPICTING THE HIGHER/STRONGER CONVECTIVE COVERAGE ACROSS THE NW PIEDMONT AHEAD OF A DRIVING UPPER SHORTWAVE. FREEZING LEVELS/WET BULB HEIGHTS IN THOSE AREAS SUPPORT MARGINAL SEVERE HAIL WITH 55 DBZ CORE HEIGHTS TO 19 TO 20 KFT. THE BETTER PRE/FRONTAL TSRA SHOULD MOVE EAST THROUGH 00Z THIS EVENING...BUT WITH SHRA AND ISOLD TSRA COVERAGE LINGERING THROUGH THE EVENING HOURS. POPS HAVE BEEN REORIENTED TO ACCOUNT FOR THIS. OTHERWISE...A COLD FRONT WILL APPROACH FROM THE NW AND THEN MOVE SLOWLY ACROS THE REGION OVERNIGHT THROUGH DAYBREAK MONDAY. THE POTENTIAL EXISTS FOR PATCHY FOG IN AREAS WHERE WINDS SUBSIDE BEFORE THE DRYING FRONT MOVES THROUGH. MINIMUM TEMPERATURES WILL BE AROUND FIVE DEGREES ABOVE NORMAL UNDER CLOUD COVER. THE COLD FRONT IS EXPECTED TO MOVE EAST THROUGH MONDAY...WITH CLEARING SKIES AND NW WINDS. HIGH TEMPERATURES WILL BE AROUND FIVE DEGREES ABOVE NORMAL IN DOWNSLOPE WARMING. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 255 PM SUNDAY...MEAN TROF REMAINS OVER THE ERN US THRU THE SHORT RANGE. THIS ALLOWS A SERIES OF WEAK SHORT WAVES TO MOVE THRU THE FLOW AND ACROSS THE AREA EACH DAY. AT THE SFC...A COLD FRONT DROPS SOUTH ACROSS THE CWFA AND STALLS OVER THE SRN CWFA OR JUST SOUTH OF THE AREA. WITH THE FRONT STALLED NEAR THE AREA...WAVES TRY TO DEVELOP ALONG THE FRONT IN RESPONSE TO THE SHORT WAVES MOVING THRU. THE GUIDANCE AGREES ON CLOUDS DEVELOPING AND MOVING ACROSS THE AREA. HOWEVER...THE NAM DEVELOPS QUITE A BIT OF ISENTROPIC LIFT ALONG THE FRONT AS AN H85 LOW DEVELOPS AND PRODUCES SLY FLOW. THE GFS DOES SOMETHING SIMILAR...BUT WEAKER AND EAST OF OUR CWFA. THE SREF HAS CLOUDS SIMILAR TO THE GFS AND PRECIP SIMILAR TO BUT LESS MAGNITUDE THAN THE NAM. GIVEN THE UNCERTAINTY...WILL KEEP THE FCST DRY THRU THE PERIOD...BUT SHOW INCREASING CLOUDS EARLY...THEN SLOWLY SHIFT THEM SOUTH. WITH THE INCREASE IN CLOUDS...LOW TEMPS LOOK TO BE WARMER THAN EARLIER EXPECTED WHICH ARE SLIGHTLY BELOW NORMAL. HIGHS SHOULD BE 5 TO 10 DEGREES BELOW NORMAL. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 305 PM SUNDAY...BETTER AGREEMENT IN MEDIUM RANGE GUIDANCE TODAY. GFS AND ECMWF OPEN A SRN STREAM WAVE AND MOVE IT ACROSS THE SERN US DURING THE FRIDAY TIME FRAME. THEY ALSO BOTH HAVE A MILLER-A LOW MOVING ALONG THE GULF COAST THU WHICH THEN RIDES UP THE EAST COAST FRI. THIS BRINGS QUITE A BIT OF MOISTURE INTO THE AREA OVER A DAMMING SFC HIGH PRESSURE RIDGE. PRECIP SLOWLY MOVES IN WED NITE... BECOMES WIDESPREAD THU AND THU NITE...THEN TAPERS OFF FRI. COULD SEE SOME WINTRY MIX ACROSS THE HIGHEST ELEVATIONS OF THE NRN MTNS AS PRECIP MOVES IN LATE WED NITE. HOWEVER...DO NOT EXPECT ANY SIGNIFICANT ACCUMS ATTM. TEMPS WILL BE BELOW NORMAL THU AND FRI. ZONAL FLOW DEVELOPS SAT AND SUN. GUIDANCE KEEPS THE FCST DRY AS A SFC LOW AND ASSOCIATED WARM FRONT REMAIN NORTH OF THE AREA. TEMPS SAT RISE TO NEAR NORMAL THEN AROUND NORMAL FOR SUN. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... AT KCLT...LATEST LAPS CAPE ANALYSIS SHOWS 500 TO 600 J/KG FOR NEARBY SFC BASED VALUES LATE THIS AFTN. GIVEN THE CONVECTION ONGOING OVER THE NW PIEDMONT AND ADDITIONAL WEAK ACTIVITY MOVING NE TOWARD THE CLT METRO AREA...WILL KEEP THE TEMPO TS GOING 22Z TO 00Z...WITH BROADER SHOWER COVERAGE THROUGH THE EVENING HOURS. TEMPO MVFR CLOUDS ARE LIKELY IN PRE/FRONTAL AIRMASS TONIGHT...WITH THE COLD FRONT PASSAGE LIKELY OCCURRING TOWARD DAYBREAK MONDAY. THIS WILL CAUSE WINDS TO VEER TO THE NW...AND THE CIG TO RISE TO VFR BEFORE ERODING. ELSEWHERE...TS CHANCES REMAIN BEST AT KHKY THROUGH 23Z...WITH MAINLY TEMPO SHRA ELSEWHERE IN THE WARM SECTOR AIRMASS AHEAD OF THE COLD FRONT APPROACHING FROM THE NW. WINDS WILL REMAIN GUSTY FROM THE SW AT THE UPSTATE SITES. CIGS ARE EXPECTED TO REMAIN LOW VFR THROUGH THE EVENING...BUT WITH TEMPO MVFR PSBL AT TIMES LATE THIS EVENING/OVERNIGHT UNTIL THE COLD FRONT MOVES THROUGH TOWARD DAYBREAK MON. THE COLD FROPA WILL VEER WINDS FROM SW TO NW THROUGHOUT...WITH ANY LINGERING CIGS ERODING. AT KAVL...WINDS WILL REMAIN CHANNELED FROM THE NW. OUTLOOK...FAIR WEATHER EXPECTED LATE MON. ANOTHER COLD FRONT MOVES THROUGH ON TUESDAY...BUT RESTRICTIONS LOOK DOUBTFUL WITH THIS SYSTEM. DRY HIGH PRESSURE SETTLE OVER THE AREA ON WEDNESDAY. A GULF COAST SYSTEM WILL SPREAD CIGS AND PRECIP OVER THE AREA ON THU...AND RESTRICTIONS ARE POSSIBLE. CONFIDENCE TABLE... 21-03Z 03-09Z 09-15Z 15-21Z KCLT HIGH 99% HIGH 88% HIGH 91% HIGH 100% KGSP HIGH 100% HIGH 92% MED 78% HIGH 100% KAVL HIGH 95% HIGH 81% HIGH 83% HIGH 100% KHKY HIGH 97% MED 72% HIGH 87% HIGH 100% KGMU HIGH 100% HIGH 95% MED 73% HIGH 100% KAND HIGH 100% HIGH 90% MED 79% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...PAT NEAR TERM...HG/JAT SHORT TERM...RWH LONG TERM...RWH AVIATION...HG/JAT
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
317 PM CDT SUN MAR 31 2013 .SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...FIRST CONCERN IS CONVECTION TONIGHT. STILL A GOOD DEAL OF UNCERTAINTY WHETHER ANYTHING GETS INTO THE CWFA THIS EVENING...AND HOW FAR SOUTH IT WILL MOVE. WILL MAKE LAST MINUTE ADJUSTMENTS ON FORECAST BASED ON RADAR TRENDS AND 4 KM MODEL TRENDS...BUT THINK ACTIVITY WILL AT BEST SCRAPE OUR NORTHERN AREAS BEFORE DISSIPATING WITH THE SETTING OF THE SUN AND THE APPROACH OF MARINE ENVIRONMENT. STILL...TO MATCH UP WITH SURROUNDING OFFICES WILL GO WITH LOW CHANCE POPS EXTREME NORTHERN TIER AND SLIGHT CHANCE A BIT FARTHER SOUTH. AM GOING A BIT FARTHER SOUTH THAN EXPECTING FOR NOW OUT OF RESPECT FOR HRRR MODEL AND ECMWF (THE LATTER MODEL DID NOT DO SO WELL A FEW DAYS AGO WITH WEEKEND POP FORECAST SO RESPECT NOT AS GOOD). AFTER ANY CONVECTION WANES...QUIET WITH ABOVE NORMAL TEMPERATURES AND AM JUST GOING A DEGREE OR TWO (AT BEST BELOW THIS MORNINGS LOW TEMPERATURES)...GIVEN LIGHTER WINDS OVERNIGHT AND SOME AREAS OF FOG LIKELY TO OCCUR. SHOULD BE COOLER MONDAY GIVEN COOLER BOUNDARY LAYER BUT SILL GENERALLY GOING ABOVE GUIDANCE MOST AREAS AND KEEPING A DRY FORECAST. COULD HAVE SOME CONVECTION MONDAY NIGHT WHICH COULD DEVELOP NORTH AND WEST OF CWFA AND DRIFT IN...WITH RICH THETA-E AIR OVER THAT REGION SO HAVE SLIGHT CHANCE POPS OUT WEST. AGAIN AM GOING ABOVE MOS NUMBERS MONDAY NIGHT. && .MARINE (TONIGHT THROUGH MONDAY NIGHT)...HAVE INCLUDED SEA FOG IN THE FORECAST...WHICH WILL BE THE MAIN CONCERN FOR AT LEAST THE NEXT TWO PERIODS IF NOT THE THIRD. WINDS EXPECTED TO REMAIN BELOW SCA CRITERION...WITH WEAK TO MODERATE EASTERLY WINDS MONDAY AND MONDAY NIGHT. && .LONG TERM (TUESDAY THROUGH SUNDAY)...THE CHALLENGE WITH THE EXTENDED FORECAST MAINLY REMAINS WITH RESPECT TO THE POTENTIAL FOR MUCH NEEDED RAINFALL ON TUESDAY AND WEDNESDAY. 500MB LOW PRESSURE AND ASSOCIATED TROUGH CURRENTLY OFF THE WEST COAST WILL MOVE INTO THE SOUTHWESTERN CONUS THROUGH THE EARLY PART OF THE WORK WEEK. MEANWHILE...PWAT VALUES WILL CONTINUE TO INCREASE ACROSS THE REGION AS PERSISTENT ONSHORE FLOW PREVAILS AT THE SURFACE AND 850MB WINDS TURN MORE OUT OF THE SOUTH/SOUTHEAST. TEMPERATURES WILL ALSO CLIMB ON TUESDAY AFTERNOON WITH AN INCREASE IN CLOUD COVER...HIGH TEMPERATURES WILL REMAIN ABOVE SEASONAL AVERAGES. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BEGIN TO INCREASE BY TUESDAY AFTERNOON AS DISTURBANCES ON THE SOUTHERN PERIPHERY OF THE MID/UPPER LEVEL TROUGH APPROACH SOUTH TEXAS. TUESDAY NIGHT INTO WEDNESDAY MORNING TIME FRAME APPEARS TO BE THE BEST WINDOW FOR WIDESPREAD SHOWERS AND THUNDERSTORMS AS THE MAIN DISTURBANCE NEARS THE REGION...AND 850MB WINDS CONTINUE OUT OF THE SOUTH/SOUTHEAST. THIS SHOULD KEEP DEEP MOISTURE UP TO 700MB-800MB ACROSS SOUTH TEXAS WITH PWAT VALUES IN THE 1.4-1.6 INCH RANGE. THE FORECAST MODELS THEN DIFFER ON THE EXACT TIMING OF A FRONTAL PASSAGE THAT WILL AID IN DRYING OUT CONDITIONS ALOFT AND PUT AND END TO RAIN CHANCES. HAVE WENT WITH A BLEND OF MAINLY THE GFS/ECMWF AND HAVE THE FRONTAL BOUNDARY SLOWLY SLIPPING DOWN INTO SOUTH TEXAS WEDNESDAY AFTERNOON AND OFFSHORE DURING THE EVENING HOURS. WILL CONTINUE LINGERING SHOWERS OVER EASTERN AREAS AND OVER THE OFFSHORE WATERS THROUGH WEDNESDAY NIGHT. CONDITIONS DRY OUT ALOFT AND SURFACE MOISTURE PUSHES OUT WITH NORTHERLY FLOW DEVELOPING IN WAKE OF THE FRONTAL PASSAGE. THIS WILL COOL TEMPERATURES WEDNESDAY NIGHT THROUGH FRIDAY MORNING BEFORE ONSHORE FLOW RESUMES AS SURFACE HIGH PRESSURE QUICKLY SHIFTS EASTWARD. FRIDAY AND BEYOND...TEMPERATURES WARM WITH NO MENTION OF PRECIPITATION. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 67 84 68 83 68 / 10 10 10 40 60 VICTORIA 65 83 66 80 62 / 30 10 10 50 80 LAREDO 69 91 69 87 66 / 10 10 20 40 40 ALICE 66 88 67 85 67 / 10 10 10 40 50 ROCKPORT 67 78 68 76 66 / 10 10 10 40 70 COTULLA 67 88 67 84 64 / 30 10 20 50 50 KINGSVILLE 67 87 68 83 69 / 10 10 10 40 50 NAVY CORPUS 69 77 69 79 69 / 10 10 10 40 60 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM RG/82...LONG TERM
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
100 PM CDT SUN MAR 31 2013 .DISCUSSION... 18Z TAF DISCUSSION BELOW. && .AVIATION... MAIN ISSUE WILL BE CONVECTION THE NEXT 6-9 HRS OVER SE TX. FRONTAL BOUNDARY PUSHING INTO THE AREA MAY INITIATE A FEW STORMS AND ALREADY SEE THAT NEAR KUTS. HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON CONVECTION SO FAR. ITS GUIDANCE SUGGESTS INCREASED THREAT THROUGH THE AFTERNOON AS SHORTWAVE TROUGH IN W TX MOVES EAST THIS AFTERNOON. WILL GO WITH VCTS FOR ALL AREAS AND LIKELY AMEND AS STORMS DEVELOP. SHOULD A LINE OF STORMS DEVELOP...MAY BE ABLE TO GIVE BETTER TIMING OF CONVECTION IN TAFS. DO EXPECT ACTIVITY TO DIMINISH FROM 00-02Z THIS EVENING. SHOULD THERE BE DECENT RAINFALL...THINK THAT WITH LIGHT WINDS COULD GET SOME FOG LIMITING VSBY. MODELS ALSO HINT AT ANOTHER ROUND OF VERY LOW CIGS. WILL GO WITH MVFR/IFR CIGS FOR MOST SITES TONIGHT INTO TOMORROW MORNING. THINK CIGS SHOULD GO VFR LATE MORNING TOMORROW THROUGH AFTERNOON. 39 && .PREV DISCUSSION... /ISSUED 1131 AM CDT SUN MAR 31 2013/ DISCUSSION... NOT A LOT OF CHANGES TO THE GOING FCST FOR THE UPDATE. STILL KEEP- ING A CLOSE EYE ON THE CONVECTION ALONG THE FRONTAL BOUNDARY THAT IS MOVING INTO OUR NRN MOST ZONES. LOOKS LIKE SOME WEAKENING OVER THE TRAILING END OF THE LINE AS IT APPROACHES HOUSTON COUNTY WITH THE STRONGEST ACTIVITY FURTHER E/NE ON THE LINE. NO REAL ARGUMENT WITH THE IDEA OF THIS BOUNDARY LINGERING OVER THE NRN PORTIONS OF THE CWA AS THE CONVECTION CONTINUES TO DIE OFF. SHORT RANGE PROGS STILL SHOWING ADDITIONAL DEVELOPMENT LATE THIS AFTN/EARLY EVENING WITH THE APPROACH/PASSAGE OF A SHORTWAVE. SEEING HINTS OF THIS AS PER RADAR/SATELLITE LOOPS OVER SOUTH CENTRAL TX ATTM. COULD BE AN ACTIVE LATTER PART OF THE SHIFT HOPPING INTO THE NEXT ONE. 41 PREV DISCUSSION... /ISSUED 429 AM CDT SUN MAR 31 2013/ SOUTHEAST TEXAS CLOSES OUT THE MONTH OF MARCH WITH A CHANCE OF MAINLY AFTERNOON THROUGH EARLY EVENING SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE APPROACH OF A WEAK COLD FRONT FROM THE NORTH AND AN UPPER LEVEL DISTURBANCE FROM THE WEST. CONDITIONS APPEAR TO BE FAVORABLE FOR SOME OF THE STORMS TO BECOME STRONG OR SEVERE...MAINLY ALONG AND NORTH OF INTERSTATE 10. RAIN CHANCES WILL BE DECREASING OVERNIGHT...AND SOME LOCATIONS MIGHT END UP DEALING WITH SOME FOG DEVELOPMENT. MONDAY LOOKS QUIET. RAIN CHANCES COME BACK INTO THE FORECAST BEGINNING MONDAY NIGHT AND TUESDAY AS MOISTURE LEVELS BEGIN TO RISE...AND THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS LOOKS LIKE IT MIGHT BE FOCUSING ON A TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON TIME PERIOD AS IMPULSES ASSOCIATED WITH THE LOW CURRENTLY OFF THE CALIFORNIA COAST MOVE ACROSS THE STATE. PORTIONS OF OUR AREA LOOK TO HAVE THE POTENTIAL TO SEE AN INCH OR TWO OF RAIN AROUND MID WEEK WITH THE GREATEST AMOUNTS POSSIBLY FOCUSING NEAR THE COAST OR OFFSHORE. THIS EARLY MARCH STORM SYSTEM EDGES OFF TO THE EAST ON THURSDAY...AND A COOLER AND DRIER AIR MASS SETTLES INTO THE AREA TO CLOSE OUT THE WEEK. WARMER TEMPERATURES ARE EXPECTED OVER THE WEEKEND AS WINDS COME BACK AROUND TO THE SOUTH AND SOUTHEAST. 42 CLIMATE... HOW DRY WILL MARCH END UP? - FOR IAH...THE MONTHLY RAINFALL TOTAL OF 0.54 INCHES CURRENTLY RANKS AS THE 6TH DRIEST MARCH ON RECORD. IAH NEEDS 0.24 INCHES OF RAIN TODAY TO END UP OUT OF THE TOP 10. IAH`S DRIEST MARCH ON RECORD IS A TRACE OF RAIN IN 1916. - FOR HOU...THE MONTHLY RAINFALL TOTAL OF 0.56 INCHES CURRENTLY RANKS AS THE 6TH DRIEST MARCH ON RECORD. HOU NEEDS 0.32 INCHES OF RAIN TODAY TO END UP OUT OF THE TOP 10. HOU`S DRIEST MARCH ON RECORD IS 0.07 INCHES IN 1953. - FOR GLS...THE MONTHLY RAINFALL TOTAL OF 0.19 INCHES CURRENTLY RANKS AS THE 4TH DRIEST MARCH ON RECORD. GLS NEEDS 0.20 INCHES OF RAIN TODAY TO END UP OUT OF THE TOP 10. GLS`S DRIEST MARCH ON RECORD IS 0.06 INCHES IN 1953. 42 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 79 62 81 60 75 / 60 30 10 30 60 HOUSTON (IAH) 78 62 81 62 74 / 50 40 10 30 60 GALVESTON (GLS) 76 64 76 65 71 / 30 30 10 20 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...40 AVIATION/MARINE...39
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1254 PM CDT SUN MAR 31 2013 .DISCUSSION...SEE 18Z AVIATION DISCUSSION. && .AVIATION...MODELS DO NOT AGREE ON WHETHER WE WILL HAVE DENSE FOG WITH STRATUS...OR LIGHT FOG AND STRATUS. GFS HAS LIGHT BOUNDARY LAYER WINDS (MORE FOG) AND NAM HAS STRONGER WINDS (MORE STRATUS/LIGHT FOG). WITH EASTERLY FLOW EXPECTED TOWARD MORNING AND BEING RELATIVELY WEAK...AM GOING TO GO WITH FOG GENERALLY NOT DENSE BUT WITH LOW STRATUS. WITH EAST WINDS...FOG AND STATUS LIKELY TO BE SIMILAR AT KCRP (COULD GET SOME SEA FOG MOVING INLAND) AS AT KALI (MORE FOG-PRONE AREA). OVERALL...WILL BEGIN SEEING MVFR CONDITIONS BY 06Z EASTERN TAFS AND LIFR (AT LEAST TEMPO) BETWEEN 08Z AND 12Z. FOR KLRD...WILL SEE MVFR/IFR CONDITIONS AROUND 08Z. CONDITIONS SHOULD IMPROVE TO VFR BY 16Z ALL TERMINALS EXCEPT KVCT WHERE WILL HAVE MVFR BY 16Z AND THEN THROUGH THE END OF THE FORECAST. CONCERNING CONVECTION...THINK IT WILL STAY OUT OF THE TERMINALS TONIGHT (SPC 4KM MODEL HAS CONVECTION GOING TO THE COAST BUT THINK IT IS NOT ACCOUNTING FOR MORE STABLE MARINE LAYER ENVIRONMENT...MOST OTHER MODELS KEEPING IT OUT OF TERMINALS). IF ANY CONVECTION WOULD OCCUR IT WOULD BE KVCT AND CONFIDENCE IN ACTIVITY GETTING THERE TOO LOW AT THIS TIME FOR EVEN A VCTS. WILL MONITOR SITUATION HOWEVER. && .PREV DISCUSSION... /ISSUED 1000 AM CDT SUN MAR 31 2013/ DISCUSSION...JUST MADE SOME MINOR MODIFICATIONS TO GRIDS (MAINLY MOISTURE AND MINOR AT THAT) BUT OTHERWISE NO REAL CHANGES NEEDED. NEW NAM12 RUN HAS CONVECTION APPROACHING AREA AROUND 00Z BUT THEN WEAKENS IT AS IT MOVES SOUTHWARD. HRRR MODEL HAS CONVECTION TOO BUT FARTHER EAST AND PUSHES IT A BIT FARTHER SOUTH (BUT NOT MUCH). ALL IN ALL...THIS JUSTIFIES MAINTAINING THE 20 POPS OVER THE NORTHERN TIER OF AREA AS PREVIOUSLY FORECAST FOR TODAY. WILL LET TEMPERATURE FORECAST RIDE. WILL UPDATE PFM AND AFM TEXT PRODUCTS BUT ZFPCRP SEEMS OK FOR NOW. MARINE...HAVE HAD OBSERVATIONS OF FOG/SEA FOG OVER THE GULF WATERS THIS MORNING...PATCHY DENSE AT TIMES. HAVE WRITTEN MARINE WEATHER STATEMENT TO HIGHLIGHT CONCERN MAINLY FOR TONIGHT AND MONDAY...AS SOME OBSERVATIONS HAVE DEW POINTS AROUND 70F THIS MORNING AND SHELF TEMPS STILL IN THE MID/UPPER 60S. WILL LOOK AT LATER PERIODS ONCE NEW MODEL RUNS AND OBSERVATIONS COME IN. PREV DISCUSSION... /ISSUED 626 AM CDT SUN MAR 31 2013/ DISCUSSION...UPDATE FOR 12Z AVIATION. AVIATION...BKN-OVC 500-1500 STRATUS DECK IN PLACE ACROSS EASTERN PORTIONS OF SOUTH TEXAS THIS MORNING...ALONG A HBV-BEA-VCT LINE EAST TO THE COAST. STRATUS DECK WILL GRADUALLY ERODE 15Z-18Z WITH VFR CONDITIONS FOR THIS AFTERNOON. S TO SE WINDS 6-12 KTS INCREASING TO 10-15 KTS AFTER 15Z...AND INCREASING FURTHER AT CRP 15-20 KTS WITH GUSTS TO 25 KTS THIS AFTERNOON. IFR CIGS WILL QUICKLY RE-DEVELOP EARLY THIS EVENING FROM E TO W. PREV DISCUSSION... /ISSUED 351 AM CDT SUN MAR 31 2013/ SHORT TERM (TODAY THROUGH MONDAY)...MID AND UPPER LEVEL SHORTWAVE DIVING SOUTHEAST THROUGH SOUTH-CENTRAL PLAINS EARLY THIS MORNING WITH A SECOND SHORTWAVE TROUGH ACROSS NEW MEXICO TRACKING EAST INTO TEXAS. COLD FRONT HAS ENTERED THE PANHANDLE AND WILL PUSH SOUTH THROUGH WEST-CENTRAL TEXAS THIS MORNING. SOUTH OF THE FRONT ACROSS SOUTH TEXAS...WARM CONDITIONS WILL PREVAIL FOR THIS EASTER SUNDAY. INITIALLY MODELS INDICATING SOME SLIGHT DRYING TAKING PLACE NOW THROUGH 18Z IN THE 925MB-850MB LAYER...BUT THEN MOISTENING BACK UP ACROSS THE CENTRAL AND NORTHERN COUNTIES LATE THIS AFTERNOON...IN ADVANCE OF THE WEAKENING COLD FRONT ENTERING THE HILL COUNTRY AND SOUTH-CENTRAL TEXAS. BACKING LOW LEVEL FLOW AHEAD OF THE SYSTEM MAY YIELD AN ISOLATED SHOWER OR THUNDERSTORMS ACROSS THE CENTRAL COUNTIES LATER THIS AFTERNOON WHERE PWATS POOLED AROUND 1.5"...BUT THE MAIN AREA TO WATCH WILL BE UPSTREAM CONVECTION ACROSS THE EWX CWA CLOSER TO THE FRONT AND SECOND SHORTWAVE. HI RESOLUTIONS MODELS HAVE BEEN INDICATING THIS CONVECTION POSSIBLY MAKING IT INTO THE FAR NORTHERN CWA LATE AFTERNOON/EARLY EVENING...WITH 00Z ECMWF AND 00Z NAM12 ALSO HINTING AT THIS. SHOULD NOTE THAT THE 00Z 4KM ARW/NMM WAS SHOWING CONVECTIVE COMPLEX REACHING THE COAST THIS EVENING BUT AM DISCOUNTING THIS FOR THE TIME BEING...AND THINKING THAT IF CONVECTION MAKES IT INTO THE AREA...IT WOULD LIKELY BE CONFINED TO NORTHERN AND WESTERN AREAS OF THE CWA...AS CIN WOULD BE RAPIDLY INCREASING IN THE EARLY EVENING ACROSS THE COASTAL PLAINS BEHIND THE SEA-BREEZE. GIVEN THE INSTABILITY FORECAST TO DEVELOP LATE AFTERNOON ACROSS THE BRUSH COUNTRY (1700-2000 J/KG CAPE)...STEEP MID LEVEL LAPSE RATES...AND DEEP LAYER SHEAR OF AROUND 50 KTS OVER THE CWA...ISOLATED STRONG TO SEVERE STORMS ARE POSSIBLE. SPC HAS IN FACT EXTENDED SOUTHWARD THE SLIGHT RISK INTO THE CWA...ALONG AND NORTH OF A LINE FROM JUST NORTH OF LAREDO TO ALICE TO VICTORIA. IF CONVECTION DOES DEVELOP OVER OR INTO THE CWA IT SHOULD DIMINISH LATE IN EVENING WITH LOSS OF HEATING. SLIGHTLY COOLER TONIGHT...WITH WINDS BACKED EAST AND NORTHEAST. PATCHY TO AREAS OF FOG DEVELOPING OVERNIGHT. SLIGHTLY COOLER (BUT STILL WARM) ON MONDAY ACROSS SOUTH TEXAS. ECMWF INDICATING QPF ACROSS THE RIO GRANDE PLAINS AND EDWARDS PLATEAU ON MONDAY...WHERE PWATS STILL POOLED NEAR 1.5"...BUT AM KEEPING FORECAST DRY DUE TO LOW CONFIDENCE. LONG TERM (MONDAY THROUGH SATURDAY)...CHALLENGING FORECAST CONTINUES THROUGH THE EXTENDED...HOWEVER EACH NEW MODEL RUN BRINGS THE DIFFERENT GUIDANCE OPTIONS CLOSER TOGETHER...WELL...EXCEPT FOR THE NAM...WHICH IS A PRETTY FAR OUTLIER. WILL FOCUS MAINLY TOWARD THE GFS AND ECMWF THROUGHOUT THE FORECAST. THESE HAVE COME IN QUITE GOOD AGREEMENT WITH FRONTAL PASSAGE TIMING BEING WEDNESDAY AFTERNOON. (THE NAM MUCH FASTER THAN THIS...AND THE CANADIAN A BIT SLOWER.) TOUGH PART OF THE FORECAST IS PRECIP TIMING AND AMOUNTS. COULD SEE SOME ISOLATED ACTIVITY BY MONDAY NIGHT...BUT BETTER CHANCES BEGIN ON TUESDAY. WITH FAVORABLE ISENTROPIC LIFT PATTERN SETTING UP...AND PLENTY OF MOISTURE POOLING ACROSS THE AREA...SEEMS A GOOD CHANCE FOR A WIDESPREAD RAIN ACROSS SOUTH TEXAS. WITH A SUFFICIENTLY WEAKENED CAP WILL HAVE THE POTENTIAL FOR THUNDERSTORMS TUESDAY AND WEDNESDAY. ONE THING NOTABLE SEPARATING THIS EVENT FROM OTHER FRONTS/PRECIP CHANCES WE/VE HAD RECENTLY...WINDS IN THE LOWER LEVELS OF THE ATMOSPHERE STAY SOUTHEAST OR SOUTH THROUGH TUESDAY BEFORE VEERING SOUTHWEST WEDNESDAY MORNING. THIS WOULD ALLOW FOR A MOIST/SATURATED LAYER UP TO AROUND 850MB. HAVE NOT MADE MUCH CHANGE TO PREVIOUS POP FORECAST...MAXING OUT AT 70 POPS ON TUESDAY NIGHT AND EARLY WEDNESDAY...THEN TRAILING OFF WEDNESDAY NIGHT. UNLESS FRONTAL TIMING BACKS UP FURTHER...THINK PRECIP SHOULD BE DONE BY SUNRISE THURSDAY AS UPPER LOW/TROUGH LIFTS OUT OF THE AREA. TOUGH TO MAKE A SPECIFIC CALL ON PRECIP TOTALS AT THIS TIME...BUT CERTAINLY HAVE THE POTENTIAL FOR AN INCH OR MORE OF RAIN FOR SOME OF US...BEST CHANCES BEING THE NORTHEAST PORTION OF THE FORECAST AREA. CURRENTLY HAVE A GENERALLY RANGE OF ONE HALF TO ONE INCH ACROSS THE CWA. AS FAR AS TEMPERATURES...WARMED THINGS UP A BIT ON WEDNESDAY WITH FRONT NOT COMING THROUGH UNTIL THE AFTERNOON...HOWEVER WITH NEARLY OVERCAST SKIES AND PRECIP IN THE AREA WILL BE SEVERAL DEGREES COOLER THAN TUESDAY. WILL ONLY REALLY SEE ONE DAY OF NORTHERLY WINDS/COLD ADVECTION BEHIND THE FRONT BEFORE HIGH PRESSURE RIDGE PUSHES OFF TO THE EAST BY FRIDAY. THUS A COOL DAY ON THURSDAY...BUT GRADUALLY WARMING TEMPS FRIDAY INTO THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 87 64 85 68 81 / 10 10 10 10 40 VICTORIA 83 61 83 65 78 / 20 20 10 20 50 LAREDO 94 68 89 68 86 / 10 10 10 20 40 ALICE 91 64 89 68 82 / 10 10 10 10 40 ROCKPORT 78 64 77 66 77 / 10 10 10 20 40 COTULLA 89 64 88 67 84 / 20 30 10 20 50 KINGSVILLE 89 64 86 67 83 / 10 10 10 10 40 NAVY CORPUS 81 66 79 68 79 / 10 10 10 10 40 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...AVIATION