Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/01/13


AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1215 PM PDT SAT MAR 30 2013 UPDATED CLIMATE SECTION .DISCUSSION...AS OF 8:29 AM PDT SATURDAY...IR SATELLITE AND KMUX PRETTY MUCH SAY IT ALL...A STORM SYSTEM IS APPROACHING THE BAY AREA WITH A MIXTURE OF CLOUDS AND SHOWERS. AS MENTIONED ON THE PREVIOUS DISCUSSION...MUCH OF THE SHORT TERM WEATHER CONCERNS WILL BE ASSOCIATED WITH A SFC LOW NEAR 34N/132W. KMUX RADAR IMAGERY CONTINUES TO INDICATE SHOWER ACTIVITY OFF THE NORTH BAY COAST AND PARTS OF THE NORTH BAY. HOWEVER...THESE SHOWERS ARE BEING DETECTED AT ROUGHLY 10-12K FEET AGL. THE MORNING KOAK SOUNDING SHOWS A MOIST LAYER AROUND 10K FEET...BUT A LARGE DRY POCKET OF AIR JUST BELOW 10K FEET. THE ECHOES DETECTED ON RADAR ARE PROBABLY NOT REACHING THE GROUND. THIS IS FURTHER CONFIRMED BY THE LACK OF SFC REPORTS FOR MEASURABLE PRECIP. THAT BEING SAID...PATCHY STRATUS DOES EXIST ALONG THE COAST WITH LIGHT DRIZZLE BEING REPORTED. ALSO...DURING THE MORNING HOURS A FEW SPRINKLES MAY BE POSSIBLE WITH THE RADAR ECHOES...BUT WIDESPREAD SHOWERS SEEMS UNLIKELY. NO UPDATE PLANNED AT THIS TIME. WILL CONTINUE TO MONITOR DEVELOPING SHOWERS AND APPROACHING STORM SYSTEM. THERE WILL BE A BETTER CHANCE FOR SHOWERS LATE THIS AFTERNOON AND EVENING AS THE PARENT SFC LOW MOVES CLOSER TO THE COAST. IN FACT...SOME OF THE 12Z MODEL GUIDANCE...INCLUDING THE RAP AND HRRR...KEEP THE BULK OF THE MOISTURE OFF THE COAST UNTIL AFTER 00Z SUNDAY. THE OTHER INTERESTING ITEM OF NOTE...THE NAM12 FCST SOUNDINGS STILL DEVELOP CONVECTION OVER THE NORTH BAY THIS AFTERNOON...CAPE 500 J/KG WITH LITTLE CIN AND LI/S MINUS 3. NOT TOTALLY BUYING OFF ON THIS YET GIVEN THE CLOUD COVER/WEAK MARINE LAYER AND LACK OF SOLAR HEATING EXPECTED. BETTER CHANCE FOR CONVECTION ON SUNDAY AS THE UPPER LOW AND COLD AIR ALOFT PASS OVERHEAD. THE BULK OF THE RAIN STILL LOOKS TO OCCUR DURING THE OVERNIGHT HOURS TONIGHT AND SUNDAY. HIGH PRESSURE BUILDS OVER THE REGION ON MONDAY AND ANY LINGERING SHOWERS WILL DIMINISH. NAILING DOWN PRECIP AMOUNTS IS SOMEWHAT PROBLEMATIC GIVEN THE CONVECTIVE NATURE OF PRECIP TONIGHT THROUGH EARLY MONDAY. FOR NOW...BEST GUESS CONTINUES INDICATE A FEW TENTHS OVER THE LOWER ELEVATIONS AND UP TO ONE INCH OVER THE COASTAL MOUNTAINS. PREVIOUS...THE NEXT RAIN CHANCES WILL OCCUR WEDNESDAY NIGHT AND THURSDAY AS AN UPPER TROUGH MOVES ONTO THE COAST...WITH ANOTHER SYSTEM POSSIBLE BY NEXT WEEKEND. && .AVIATION...AS OF 11:45 AM PDT SATURDAY...FOR 18Z TAFS. SOUTHERLY FLOW ASSOCIATED WITH UPPER LOW IS KEEPING STUBBORN LOW CLOUDS AROUND THE REGION ALONG WITH MID AND HIGH DECKS. AIRPORT LEAST IMPACTED CONTINUES TO BE SAN JOSE WHILE MVFR CLOUD DECKS CONTINUE TO COME IN AND OUT OF KSFO AND KOAK WITH SHOWERS AND IFR CONDITIONS IN THE NORTH BAY. IN GENERAL LOOK FOR LIFTING CLOUD DECKS THIS AFTERNOON AND EVENING AS THE AREA WILL BE IN A LULL REGION BEFORE THE NEXT SPOKE OF ENERGY ROTATES ONSHORE AFTER 06Z. VICINITY OF KSFO...MVFR CONDITIONS CONTINUE THROUGH 21Z BUT WITH CIG HEIGHTS CONTINUING TO LIFT THROUGH THE LATE AFTERNOON AND EVENING HOURS. NEXT BAND OF SHOWERS LOOKS TO HOLD OFF UNTIL SOMETIME AROUND MIDNIGHT. KSFO BRIDGE APPROACH...SIMILAR TO KSFO BUT WITH LESS LOW CLOUDS EXPECTED SOUTH OF THE BRIDGE AND TOWARDS KSJC THIS AFTERNOON AND EVENING. MONTEREY BAY AREA TERMINALS...STUBBORN CIGS CONTINUE TO IMPACT KMRY AND KSNS BUT WITH CLEAR SKIES JUST WEST OF KMRY AND OVER THE OCEAN EXPECTED TO DEVELOP BY LATER THIS AFTERNOON. -SHRA EXPECTED TO DEVELOP LATER THIS EVENING NEAR KMRY IN SW FLOW AHEAD OF NEXT UPPER DISTURBANCE. && .CLIMATE...DOWNTOWN SAN FRANCISCO IS ON TRACK TO HAVE ITS DRIEST JANUARY THROUGH MARCH ON RECORD. THE CITY HAS A CONTINUAL DATA SET GOING BACK TO 1850, SO IT IS NOTABLE WHEN RECORDS ARE BROKEN THERE. AS OF NOON TODAY, ONLY 1.73" OF RAIN HAS BEEN RECORDED. THIS AMOUNT IS NEARLY 1.5" BELOW THE CURRENT JANUARY THROUGH MARCH RECORD OF 3.20" SET ALL OF THE WAY BACK IN 1850. THE AVERAGE RAINFALL FOR THE SAME TIME PERIOD IS 12.22". WE WILL PROVIDE UPDATED NUMBERS AS RAIN FALLS IN SAN FRANCISCO THIS WEEKEND. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: MM AVIATION/MARINE: RWW CLIMATE: BELL VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1145 AM PDT SAT MAR 30 2013 .DISCUSSION...AS OF 8:29 AM PDT SATURDAY...IR SATELLITE AND KMUX PRETTY MUCH SAY IT ALL...A STORM SYSTEM IS APPROACHING THE BAY AREA WITH A MIXTURE OF CLOUDS AND SHOWERS. AS MENTIONED ON THE PREVIOUS DISCUSSION...MUCH OF THE SHORT TERM WEATHER CONCERNS WILL BE ASSOCIATED WITH A SFC LOW NEAR 34N/132W. KMUX RADAR IMAGERY CONTINUES TO INDICATE SHOWER ACTIVITY OFF THE NORTH BAY COAST AND PARTS OF THE NORTH BAY. HOWEVER...THESE SHOWERS ARE BEING DETECTED AT ROUGHLY 10-12K FEET AGL. THE MORNING KOAK SOUNDING SHOWS A MOIST LAYER AROUND 10K FEET...BUT A LARGE DRY POCKET OF AIR JUST BELOW 10K FEET. THE ECHOES DETECTED ON RADAR ARE PROBABLY NOT REACHING THE GROUND. THIS IS FURTHER CONFIRMED BY THE LACK OF SFC REPORTS FOR MEASURABLE PRECIP. THAT BEING SAID...PATCHY STRATUS DOES EXIST ALONG THE COAST WITH LIGHT DRIZZLE BEING REPORTED. ALSO...DURING THE MORNING HOURS A FEW SPRINKLES MAY BE POSSIBLE WITH THE RADAR ECHOES...BUT WIDESPREAD SHOWERS SEEMS UNLIKELY. NO UPDATE PLANNED AT THIS TIME. WILL CONTINUE TO MONITOR DEVELOPING SHOWERS AND APPROACHING STORM SYSTEM. THERE WILL BE A BETTER CHANCE FOR SHOWERS LATE THIS AFTERNOON AND EVENING AS THE PARENT SFC LOW MOVES CLOSER TO THE COAST. IN FACT...SOME OF THE 12Z MODEL GUIDANCE...INCLUDING THE RAP AND HRRR...KEEP THE BULK OF THE MOISTURE OFF THE COAST UNTIL AFTER 00Z SUNDAY. THE OTHER INTERESTING ITEM OF NOTE...THE NAM12 FCST SOUNDINGS STILL DEVELOP CONVECTION OVER THE NORTH BAY THIS AFTERNOON...CAPE 500 J/KG WITH LITTLE CIN AND LI/S MINUS 3. NOT TOTALLY BUYING OFF ON THIS YET GIVEN THE CLOUD COVER/WEAK MARINE LAYER AND LACK OF SOLAR HEATING EXPECTED. BETTER CHANCE FOR CONVECTION ON SUNDAY AS THE UPPER LOW AND COLD AIR ALOFT PASS OVERHEAD. THE BULK OF THE RAIN STILL LOOKS TO OCCUR DURING THE OVERNIGHT HOURS TONIGHT AND SUNDAY. HIGH PRESSURE BUILDS OVER THE REGION ON MONDAY AND ANY LINGERING SHOWERS WILL DIMINISH. NAILING DOWN PRECIP AMOUNTS IS SOMEWHAT PROBLEMATIC GIVEN THE CONVECTIVE NATURE OF PRECIP TONIGHT THROUGH EARLY MONDAY. FOR NOW...BEST GUESS CONTINUES INDICATE A FEW TENTHS OVER THE LOWER ELEVATIONS AND UP TO ONE INCH OVER THE COASTAL MOUNTAINS. PREVIOUS...THE NEXT RAIN CHANCES WILL OCCUR WEDNESDAY NIGHT AND THURSDAY AS AN UPPER TROUGH MOVES ONTO THE COAST...WITH ANOTHER SYSTEM POSSIBLE BY NEXT WEEKEND. && .AVIATION...AS OF 11:45 AM PDT SATURDAY...FOR 18Z TAFS. SOUTHERLY FLOW ASSOCIATED WITH UPPER LOW IS KEEPING STUBBORN LOW CLOUDS AROUND THE REGION ALONG WITH MID AND HIGH DECKS. AIRPORT LEAST IMPACTED CONTINUES TO BE SAN JOSE WHILE MVFR CLOUD DECKS CONTINUE TO COME IN AND OUT OF KSFO AND KOAK WITH SHOWERS AND IFR CONDITIONS IN THE NORTH BAY. IN GENERAL LOOK FOR LIFTING CLOUD DECKS THIS AFTERNOON AND EVENING AS THE AREA WILL BE IN A LULL REGION BEFORE THE NEXT SPOKE OF ENERGY ROTATES ONSHORE AFTER 06Z. VICINITY OF KSFO...MVFR CONDITIONS CONTINUE THROUGH 21Z BUT WITH CIG HEIGHTS CONTINUING TO LIFT THROUGH THE LATE AFTERNOON AND EVENING HOURS. NEXT BAND OF SHOWERS LOOKS TO HOLD OFF UNTIL SOMETIME AROUND MIDNIGHT. KSFO BRIDGE APPROACH...SIMILAR TO KSFO BUT WITH LESS LOW CLOUDS EXPECTED SOUTH OF THE BRIDGE AND TOWARDS KSJC THIS AFTERNOON AND EVENING. MONTEREY BAY AREA TERMINALS...STUBBORN CIGS CONTINUE TO IMPACT KMRY AND KSNS BUT WITH CLEAR SKIES JUST WEST OF KMRY AND OVER THE OCEAN EXPECTED TO DEVELOP BY LATER THIS AFTERNOON. -SHRA EXPECTED TO DEVELOP LATER THIS EVENING NEAR KMRY IN SW FLOW AHEAD OF NEXT UPPER DISTURBANCE. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: MM AVIATION/MARINE: RWW VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
831 AM PDT SAT MAR 30 2013 .DISCUSSION...AS OF 8:29 AM PDT SATURDAY...IR SATELLITE AND KMUX PRETTY MUCH SAY IT ALL...A STORM SYSTEM IS APPROACHING THE BAY AREA WITH A MIXTURE OF CLOUDS AND SHOWERS. AS MENTIONED ON THE PREVIOUS DISCUSSION...MUCH OF THE SHORT TERM WEATHER CONCERNS WILL BE ASSOCIATED WITH A SFC LOW NEAR 34N/132W. KMUX RADAR IMAGERY CONTINUES TO INDICATE SHOWER ACTIVITY OFF THE NORTH BAY COAST AND PARTS OF THE NORTH BAY. HOWEVER...THESE SHOWERS ARE BEING DETECTED AT ROUGHLY 10-12K FEET AGL. THE MORNING KOAK SOUNDING SHOWS A MOIST LAYER AROUND 10K FEET...BUT A LARGE DRY POCKET OF AIR JUST BELOW 10K FEET. THE ECHOES DETECTED ON RADAR ARE PROBABLY NOT REACHING THE GROUND. THIS IS FURTHER CONFIRMED BY THE LACK OF SFC REPORTS FOR MEASURABLE PRECIP. THAT BEING SAID...PATCHY STRATUS DOES EXIST ALONG THE COAST WITH LIGHT DRIZZLE BEING REPORTED. ALSO...DURING THE MORNING HOURS A FEW SPRINKLES MAY BE POSSIBLE WITH THE RADAR ECHOES...BUT WIDESPREAD SHOWERS SEEMS UNLIKELY. NO UPDATE PLANNED AT THIS TIME. WILL CONTINUE TO MONITOR DEVELOPING SHOWERS AND APPROACHING STORM SYSTEM. THERE WILL BE A BETTER CHANCE FOR SHOWERS LATE THIS AFTERNOON AND EVENING AS THE PARENT SFC LOW MOVES CLOSER TO THE COAST. IN FACT...SOME OF THE 12Z MODEL GUIDANCE...INCLUDING THE RAP AND HRRR...KEEP THE BULK OF THE MOISTURE OFF THE COAST UNTIL AFTER 00Z SUNDAY. THE OTHER INTERESTING ITEM OF NOTE...THE NAM12 FCST SOUNDINGS STILL DEVELOP CONVECTION OVER THE NORTH BAY THIS AFTERNOON...CAPE 500 J/KG WITH LITTLE CIN AND LI/S MINUS 3. NOT TOTALLY BUYING OFF ON THIS YET GIVEN THE CLOUD COVER/WEAK MARINE LAYER AND LACK OF SOLAR HEATING EXPECTED. BETTER CHANCE FOR CONVECTION ON SUNDAY AS THE UPPER LOW AND COLD AIR ALOFT PASS OVERHEAD. THE BULK OF THE RAIN STILL LOOKS TO OCCUR DURING THE OVERNIGHT HOURS TONIGHT AND SUNDAY. HIGH PRESSURE BUILDS OVER THE REGION ON MONDAY AND ANY LINGERING SHOWERS WILL DIMINISH. NAILING DOWN PRECIP AMOUNTS IS SOMEWHAT PROBLEMATIC GIVEN THE CONVECTIVE NATURE OF PRECIP TONIGHT THROUGH EARLY MONDAY. FOR NOW...BEST GUESS CONTINUES INDICATE A FEW TENTHS OVER THE LOWER ELEVATIONS AND UP TO ONE INCH OVER THE COASTAL MOUNTAINS. PREVIOUS...THE NEXT RAIN CHANCES WILL OCCUR WEDNESDAY NIGHT AND THURSDAY AS AN UPPER TROUGH MOVES ONTO THE COAST...WITH ANOTHER SYSTEM POSSIBLE BY NEXT WEEKEND. && .AVIATION...AS OF 4:47 AM PDT SATURDAY...CURRENTLY THE IR SATELLITE IMAGE IS SHOWING MID TO HIGH CLOUDS AND SOUTHERLY FLOW OVER THE FORECAST AREA. THE GOES IFR PROB PROD IS INDICATING IFR PROB GREATER THAN 60% OVER PORTIONS OF SAN FRANCISCO BAY WITH KOAK OB INDICATING BKN005. SOUTHERLY FLOW SHOULD HELP TO KEEP THE LOW CIGS OUT OF KSFO BUT THERE MAY BE SOME IFR CIGS OVER THE APPROACH. RUNWAYS SHOULD REMAIN DRY THIS MORNING WITH SHOWERS EXPECTED TO DEVELOP LATER THIS EVENING. VICINITY OF KSFO...VFR IS ANTICIPATED TODAY WITH A LOW PROBABILITY OF IFR CIGS THIS MORNING. IF IFR DOES DEVELOP CONDITIONS SHOULD IMPROVE NO LATER THAN 1700Z. GENERALLY LIGHT WINDS WILL INCREASE OUT OF THE SOUTHWEST TO 10 TO 12 KT BY 2100Z. KSFO BRIDGE APPROACH...SIMILAR TO KSFO WITH A HIGHER PROB OF IFR CIGS THIS MORNING. IF IFR CIGS DO DEVELOP CONDITIONS SHOULD IMPROVE BY 1700Z. MONTEREY BAY AREA TERMINALS...LIFR CIGS THIS MORNING WILL IMPROVE TO IFR BY 1700Z WITH CONTINUED IMPROVEMENT TO VFR BY 2000Z. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: MM AVIATION/MARINE: LARRY VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS TAUNTON MA
706 AM EDT SAT MAR 30 2013 .SYNOPSIS... HIGH PRESSURE WILL BRING DRY AND MILD WEATHER TO THE REGION TODAY INTO MOST OF SUNDAY AFTERNOON. AN APPROACHING COLD FRONT WILL BRING A PERIOD OF SHOWERS TO THE REGION SUN NIGHT WITH EVEN THE RISK FOR AN ISOLATED THUNDERSTORM. ANOTHER COLD FRONT WILL BRING COLDER WEATHER INTO THE MID PART OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 7 AM UPDATE... MID LVL SHORTWAVE IS NOW BEGINNING TO SHIFT E OF THE FORECAST AREA EARLY THIS MORNING. THIS IS ALLOWING BOTH SOME LOW TO MID STRATO- CU AND SOME LIGHT SHOWERS OVER THE ISLANDS TO BEGIN SHIFTING E OF THE AREA...GIVING WAY TO MOSTLY SKC CONDITIONS ACROSS MUCH OF THE INTERIOR. THE TREND WILL BE TOWARD THIS CLEARING EVEN IN THE E. WILL STILL NEED TO MONITOR FOR THE SLIGHT CHANCE OF AN AFTERNOON SHOWER PARTICULARLY IN THE SE...BUT IT APPEARS MUCH OF THE AY WILL BE DRY. THEREFORE WILL CONTINUE WITH NIL POPS. ADJUSTED SKIES TOWARD LATEST RAP AND ALSO UPDATED TEMPS AND DWPTS TO BRING THEM UP TO CURRENT TRENDS. PREVIOUS DISCUSSION... A MID LEVEL SHORTWAVE WAS RESULTING IN A FEW LINGERING SPRINKLES/LIGHT SHOWERS ACROSS THE CAPE AND ISLANDS VERY EARLY THIS MORNING. THIS ACTIVITY SHOULD EXIT THE REGION BY DAYBREAK. OTHERWISE...A PARTLY TO MOSTLY SUNNY AND MILD DAY IS ON TAP FOR THE REGION. ALTHOUGH 850 MB TEMPS ARE AROUND -3C...DRY NORTHWEST FLOW AND A WELL MIXED ATMOSPHERE WILL YIELD A SUPER ADIABATIC ATMOSPHERE. HIGH TEMPS SHOULD RISE INTO THE MID TO UPPER 50S...AND ITS NOT OUT OF THE QUESTION THAT A FEW SPOTS HIT THE 60 DEGREE MARK. GIVEN THE RELATIVELY WEAK PRESSURE GRADIENT...SEA BREEZES MAY DEVELOP ALONG THE VERY IMMEDIATE COAST RESULTING IN LOCALIZED COOLER CONDITIONS IN THOSE REGIONS DURING AFTERNOON. WE KEPT THE FORECAST DRY AS UPPER LEVEL TROUGH IS MOVING EAST AND ALLOWING FOR RISING HEIGHT FIELDS IN SOUTHERN NEW ENGLAND. GUESS THERE IS STILL A LOW RISK OF AN ISOLATED SPOT SHOWER NEAR THE SOUTHEAST NEW ENGLAND COAST THIS AFTERNOON...BUT NOT WORTH MENTIONING IN THE FORECAST. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... TONIGHT... A RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION. THIS WILL RESULT IN MAINLY CLEAR SKIES/LIGHT WINDS AND A GOOD NIGHT OF RADIATIONAL COOLING. DESPITE THE MILD DAY...LOW TEMPS SHOULD FALL WELL DOWN INTO THE 20S TO LOWER 30S IN MOST LOCALES BY DAYBREAK SUN. SUNDAY AND SUNDAY NIGHT... THE RIDGE OF HIGH PRESSURE MOVES OFF THE COAST EARLY ON SUN...ALLOWING FOR A SOUTHERLY FLOW OF MILD AIR TO WORK INTO THE REGION. WHILE CLOUDS WILL INCREASE DURING THE AFTERNOON FROM WEST TO EAST...A FAIR AMOUNT OF SUNSHINE IS EXPECTED FOR THE FIRST PART OF THE DAY. THIS SHOULD ALLOW HIGH TEMPS TO REACH INTO THE UPPER 50S TO AROUND 60 NORTHWEST OF BOS TO PVD LINE. SOUTHERLY FLOW OFF THE OCEAN WILL RESULT IN TEMPS A BIT COOLER SOUTHEAST OF THIS REGION...WITH HIGHS HELD DOWN INTO THE UPPER 40S AND LOWER 50S ACROSS THE CAPE/ISLANDS. EXPECT THE WEATHER TO PRETTY MUCH REMAIN DRY DURING THE DAY SUNDAY. A COLD FRONT APPROACHING FROM THE WEST WILL BRING A BAND OF SHOWERS ACROSS THE REGION SUNDAY NIGHT FOR A FEW HOURS. THERE MAY BE JUST ENOUGH ELEVATED INSTABILITY FOR A FEW EMBEDDED THUNDERSTORMS...WITH THE BEST CHANCE ALONG THE SOUTHEAST NEW ENGLAND COAST. THE MODELS INDICATE THAT TOTAL TOTALS MAY RISE INTO THE MID 50S WITH SHOWALTERS DROPPING TO AROUND ZERO...SO HAVE INSERTED SOME ISOLATED THUNDER INTO THE FORECAST. THE FRONT WILL BE FAST MOVING SO SHOWERS SHOULD ONLY LAST A FEW HOURS IN A GIVEN LOCATION...WITH RAINFALL AMOUNTS LESS THAN A HALF INCH. && .LONG TERM /MONDAY THROUGH FRIDAY/... * WARMER TEMPERATURES EXPECTED MON THEN COOLING * COOLER WEATHER MOVES BACK IN TUES AND WED * WARMING THU AND FRI...BUT WILL HAVE TO WATCH OCEAN STORM OVERVIEW AND MODEL PREFERENCES... 30/00Z MODEL GUIDANCE SUITE CONTINUES TO SHOW REASONABLY GOOD AGREEMENT THROUGH MUCH OF THE LONG TERM AND HAS BEEN DELAYING THE BREAKDOWN OF BLOCKING GREENLAND RIDGE. CPC CONTINUES TO SHOW A NEGATIVE AO PATTERN NOW INTO EARLY APRIL...WHICH SUPPORTS THIS THINKING. THE RIDGE LOOKS TO REMAIN IN PLACE THROUGH MUCH OF THE COMING WEEK AND THEREFORE HOLDS CUTOFF LOW PRES IN VICINITY OF NEWFOUNDLAND AND LABRADOR. THIS SETUP SUGGESTS TEMPERATURES GENERALLY REMAIN ON THE COOL SIDE OF NORMAL FOR MUCH OF THE WEEK. OPERATIONAL GFS AND ECMWF ARE BOTH IN AGREEMENT HERE...BUT THE ECMWF CONTINUES TO BE A BIT COLDER...AND SEEMS TO HAVE BEEN MORE PERSISTENT. THEREFORE...WILL CONTINUE WITH USING IT AS A BASELINE. DETAILS... MON INTO MON NIGHT... FOLLOWING OCCLUSION IN THE MORNING EXPECT A BRIEF LULL IN PRECIPITATION LIKELY UNTIL MID TO LATE AFTERNOON THANKS TO A FAIRLY ROBUST DRY SLOT IN ADVANCE OF AN ARCTIC COLD FRONT. THIS SECONDARY FRONT IS EXPECTED TO MOVE THROUGH BETWEEN 18Z AND 00Z TUE...WITH SOME ISOLATED RAIN SHOWERS INITIALLY. GIVEN A FAIR AMOUNT OF COLD DRY AIR ADVECTING IN RAPIDLY...MAY ACTUALLY SEE A BRIEF CHANGE OVER TO SOME SNOW SHOWERS TOWARD THE END OF THE DAY. AT THIS POINT...GIVEN THE WARM START /H85 TEMPS START HIGHER THAN 0C/ WILL LIKELY SEE LITTLE ACCUMULATION IF ANY UNLESS A BRIEF HEAVIER SNOW SHOWER OCCURS IN WHICH DYNAMIC COOLING IS ENOUGH FOR BETTER SNOW DEVELOPMENT. MAY SEE SOME WIND GUSTS EXCEEDING 30 MPH ESPECIALLY WITH THE FRONT...BUT EXPECT THAT MOST GUSTS SHOULD REMAIN BELOW WIND ADVISORY CRITERIA. TUE AND WED... ARCTIC FRONT MOVES FURTHER OFFSHORE TUE AND DRY HIGH PRES BEGINS TO BUILD IN FROM THE W. THIS ALLOWS THE CONTINUED COOL NW FLOW OVER THE REGION. MAY SEE SOME CLOUDS AND LIGHT SHOWERS PARTICULARLY IN THE NW THANKS TO DECENT MID LVL COLD ADVECTION...BUT OTHERWISE THE BEGINNING OF A MOSTLY DRY PERIOD IS EXPECTED. EXPECTING THE CONTINUATION OF SOME 20 TO 30 MPH WIND GUSTS PARTICULARLY DURING THE DAY...SO IT WILL BE BLUSTERY. H85 TEMPERATURES ARE EXPECTED TO HOVER CLOSE TO ABOUT -10C...SO TEMPERATURES IN THE LOW TO MID 40S ARE LIKELY GIVEN THE EARLY APRIL SUN. THU INTO FRI... HIGH PRES BUILDS OVER THE REGION DURING THIS PERIOD. AT THIS POINT...MOST LONG RANGE GUIDANCE SUGGESTS THE BLOCKING HIGH SHIFTS INTO THE MARITIMES AND SETS UP SUCH THAT SRN STREAM WAVE STAYS TOO FAR OFFSHORE TO AFFECT THE REGION. HOWEVER...THIS WILL NEED TO BE MONITORED SHOULD THE BLOCK SHIFT TO THE N...WHICH MAY ALLOW THIS COASTAL LOW TO AFFECT THE REGION. THE 00Z ECMWF DOES SHOW THIS MAKING A CLOSE ENOUGH PASS...SUCH THAT PRECIP MAY FALL...HOWEVER WILL CONTINUE TO HOLD THE DRY TREND CONSIDERING THIS IS THE FIRST RUN AND MANY OF ITS ENSEMBLE MEMBERS CONTINUE TO BE FURTHER OFFSHORE. EXPECTING A SLIGHT MODERATING TREND IN TEMPERATURES AS HIGH PRES SLIDES E AND SOME WEAK WARM ADVECTION DEVELOPS. NEXT WEEKEND... WHILE THIS WILL BE DEPENDENT SOMEWHAT ON EXACTLY WHAT THE SRN STREAM WAVE DOES...IT APPEARS THAT SOME HIGH PRES WILL BUILD BACK OVER THE REGION BY NEXT WEEKEND. ALLOWING FOR A GENERAL DRYING TREND. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW...HIGH CONFIDENCE THROUGH SUNDAY AFTERNOON. MODERATE CONFIDENCE SUNDAY NIGHT. VFR CONDITIONS TODAY THROUGH SUNDAY AFTERNOON. OTHERWISE...MVFR CONDITIONS BEGIN WITH A BAND OF RAIN MOVING FROM W TO E BY SUN AFTERNOON...MVFR WILL LIKELY ACCOMPANY THIS RAIN ALTHOUGH CAN/T RULE OUT A BRIEF PERIOD OF IFR. THERE ALSO MAY BE A FEW EMBEDDED THUNDERSTORMS WITH THE BEST CHANCE ALONG THE COASTAL PLAIN DURING THE EVENING AND EARLY OVERNIGHT SUN NIGHT.. KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS TODAY AND TONIGHT. WILL HAVE TO MONITOR FOR ANOTHER WEAK SEA BREEZE FOR A COUPLE OF HOURS THIS AFTERNOON. WILL TIME THIS IN THE TAF...AND WILL HAVE TO MONITOR THE STRENGTH OF THE SFC WIND...SHOULD IT DIMINISH THIS AFTERNOON THE CHANCE OF THE SEA BREEZE COMING ON SHORE IS HIGHER. KBDL TAF...HIGH CONFIDENCE IN TAF TODAY AND TONIGHT. OUTLOOK...MONDAY THROUGH WEDNESDAY... MONDAY...MODERATE CONFIDENCE IN MAINLY VFR CONDITIONS. HOWEVER...A SECONDARY FRONT MAY BRING ISOLATED MVFR CONDITIONS LATE DAY MON. TUESDAY AND WEDNESDAY...HIGH CONFIDENCE. MAINLY VFR. && .MARINE... HIGH CONFIDENCE THROUGH SUNDAY AFTERNOON THAT WINDS/SEAS WILL REMAIN BELOW SCA THRESHOLDS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN PLACE. AN APPROACHING COLD FRONT WILL LIKELY BRING A PERIOD OF SOUTHERLY SCA WIND GUSTS AND SEAS TO THE WATERS SUNDAY NIGHT. SINCE ITS A 4TH PERIOD EVENT...IT WAS TOO EARLY TO ISSUE ANY MARINE HEADLINES. OUTLOOK...MONDAY THROUGH WEDNESDAY... MODERATE TO HIGH CONFIDENCE. AFTER A SERIES OF FRONTS SUN NIGHT AND MONDAY...EXPECT NW WINDS TO BUILD AND MAINTAIN AROUND 25 TO 30 KT AT TIMES FROM LATE DAY MON INTO WED. SEAS MAY DROP A BIT ESPECIALLY ON NEAR SHORE WATERS...BUT WILL LIKELY REMAIN ABOVE 5 FT OVER OUT WATERS. SMALL CRAFT ADVISORIES ARE LIKELY FROM MON INTO WED. LOW PROBABILITY OF SOME ISOLATED GALE FORCE WIND GUSTS DURING THIS PERIOD AS WELL. && .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
NWS TAMPA BAY RUSKIN FL
355 AM EDT SAT MAR 30 2013 .SYNOPSIS... 07Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUES TO SHOW A GENERALLY BENIGN UPPER LEVEL PATTERN IN PLACE OVER THE CONUS THIS MORNING. CONVERGENT FLOW ARRIVES OVER THE PACIFIC NORTHWEST AND THEN FORMS A GENERAL WEST TO NORTHWEST FLOW PATTERN ACROSS THE REMAINDER OF THE CONUS. ONLY SIGNIFICANT ONGOING SENSIBLE WEATHER ARE THUNDERSTORMS ACROSS THE PLAINS IN ASSOCIATION WITH A WEAK IMPULSE EJECTING OUT OF THE INTER-MOUNTAIN WEST WITHIN THE MAIN FLOW. WV IMAGERY SHOWS OUR FORECAST AREA RESIDES UNDER THIS GENERAL WESTERLY FLOW ALOFT AND THIS IS CONFIRMED BY THE 30/00Z KTBW SOUNDING PROFILE. THE PROFILE FROM LAST EVENING WAS STILL QUITE DRY THROUGH THE EXTENT OF THE COLUMN...HOWEVER WE SHOULD SEE THE MID/UPPER LEVELS BEGIN TO MOISTEN SOMEWHAT OVER THE NEXT 12-18 HOURS AS THE WEAK IMPULSE NOTED ABOVE APPROACHES FROM THE NORTHWEST. AT THE SURFACE...SURFACE HIGH PRESSURE IS RIDGING BACK WESTWARD OVER THE PENINSULA AND EASTERN GULF FROM A POSITION CENTERED NORTH OF THE BAHAMAS EARLY THIS MORNING. THE RIDGE AXIS AND CLEAR SKIES OVERHEAD ARE ALLOWING YET ANOTHER COOL OVERNIGHT FOR LATE MARCH...HOWEVER UNLIKE PREVIOUS MORNING...IT DOES NOT APPEAR AS THOUGH TEMPERATURES WILL DROP ENOUGH FOR FROST TO BE A REAL CONCERN. && .SHORT TERM (TODAY THROUGH MONDAY)... TODAY/TONIGHT... SURFACE HIGH PRESSURE OFF THE SE CONUS COAST WILL RIDGE BACK ACROSS THE CENTRAL FL PENINSULA. EFFICIENT DIURNAL 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. VIRTUALLY ALL NWP GUIDANCE IS SHOWING SEA-BREEZE DEVELOPMENT BY EARLY AFTERNOON...AND WILL FOLLOW LOCAL HI-RES GUIDANCE FOR THE WIND GRIDS IN TERMS OF TIMING AND STRENGTH FOR THE INLAND PROPAGATION OF THE INITIAL BOUNDARY. THE SEA-BREEZE WILL HAVE MORE POTENTIAL FOR SIGNIFICANT INLAND PENETRATION TO THE 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 IN THE LOWER TO MIDDLE 60S ARE STILL FOUND OFF THE NATURE COAST...AND THE ONSHORE FLOW OFF THESE WATERS IS LIKELY TO DROP TEMPS BACK DOWN TOWARD THE UPPER 60S/LOW 70S NEAR THE COAST DURING THE SECOND HALF OF THE AFTERNOON. WILL SEE SOME COOLING FOR THE SUNCOAST BEACHES SOUTH OF TAMPA BAY AS WELL...HOWEVER THE WEAKER SEA-BREEZE AND RELATIVELY WARMER SHELF WATERS SHOULD LIMIT THE COOLING. PLENTY OF SUNSHINE WILL START THE DAY. DURING THE MIDDLE TO LATER PORTION OF THE AFTERNOON TIME-HEIGHT PLOTS FROM THE GFS/NAM/ECMWF ALL SHOW AN EVENTUAL INCREASE IN MID/HIGH LEVEL CLOUDS TO FILTER THE SUN IN RESPONSE TO THE APPROACH OF A SHORTWAVE IMPULSE. TONIGHT STILL LOOKS DRY AND SEASONABLY COOL. NO FROST CONCERNS EXPECTED WITH THE COOLEST LOCATIONS ONLY DROPPING INTO THE UPPER 40S BY SUNRISE. SEVERAL MODEL RUNS NOW HAVE SHOWN A DECENT SWATH OF MOISTURE COINCIDENT WITH SYNOPTIC LIFT IN THE MID/UPPER LEVELS ASSOCIATED WITH THIS SHORTWAVE DURING THE OVERNIGHT PERIOD. APPEARS TO BE ENOUGH FOR SKIES TO POTENTIALLY GO MOSTLY CLOUDY NORTH OF I-4 FOR A PERIOD. SUNDAY/SUNDAY NIGHT... INITIAL SHORTWAVE QUICKLY PULLS EAST OF THE AREA DURING THE MORNING. THE NEXT SHORTWAVE IN LINE ROTATING AROUND AN AMPLIFYING LONGWAVE TROUGH WELL TO OUR NORTH WILL BE APPROACHING DURING THE DAY...BUT SHOULD REMAIN FAR ENOUGH WEST TO HAVE LITTLE IMPACT DURING THE DAYLIGHT HOURS. LEADING THIS ENERGY...A COLD FRONT WILL PUSH INTO THE SOUTHEASTERN CONUS DURING THE DAY. THIS FRONT LOOKS TO STALL NORTH OF I-10 LATER SUNDAY OR SUNDAY NIGHT. THE FORECAST PHILOSOPHY HAS NOT CHANGED IN THE PAST 24 HOURS...AND ALTHOUGH IT IS NOT OUT OF THE QUESTION TO SEE A BRIEF SHOWER OR TWO ACROSS LEVY/CITRUS COUNTIES LATER SUNDAY/SUNDAY NIGHT...THE BETTER LOW LEVEL FOCUS FOR LIFT REMAINS PROGGED TO STAY NORTH OF OUR ZONES. OF NOTE...THE CONVECTIVE PARAMETRIZATION SCHEMES FROM A FEW OF THE SREF MEMBERS ARE STILL KICKING OFF OVER THE PENINSULA (SOUTH OF I-4) DURING SUNDAY AFTERNOON. THE GFS HAS BACKED OFF ON THIS SCENARIO...AND SURFACE DEWPOINTS IN THE 50S SEEM TO ARGUE AGAINST ANY INSTABILITY THAT WOULD CURRENTLY WARRANT SHOWER MENTION IN THE FORECAST. AVAILABLE CONVECTION ALLOWING GUIDANCE ALSO SHOW LITTLE SHOWER POTENTIAL AND WILL KEEP POPS AT SILENT 10%. TEMPERATURES WILL BE SEASONABLE WITH UPPER 70S TO AROUND 80 NORTH OF I-4 AND LOW/MID 80S FURTHER SOUTH. AFTERNOON SEA-BREEZES WILL AGAIN KEEP THE BEACHES COOLER. MONDAY... SURFACE RIDGE AXIS WILL SETTLE A BIT SOUTH WHILE THE SURFACE COLD FRONT REMAINS STALLED JUST TO THE NORTH OF I-10. AS THE NEXT SHORTWAVE IN LINE CROSSES THE AREA...BETTER CHANCES FOR SHOWERS WILL ARRIVE FOR THE NATURE COAST...ESPECIALLY NORTH OF HERNANDO COUNTY... IN CLOSER PROXIMITY TO THE FRONTAL FOCUS. ALSO...SLIGHTLY BETTER CHANCES FOR A FEW SEA-BREEZE FORCED SHOWERS MONDAY AFTERNOON FURTHER SOUTH ACROSS THE PENINSULA DUE TO BETTER LOW LEVEL MOISTURE AND SOME AIDED SUPPORT BY THE PASSING SHORTWAVE. BEST CHANCES TO SEE A BRIEF SHOWER MONDAY AFTERNOON LOOK TO BE WELL INLAND FROM THE GULF...AND MOST LIKELY OVER BY THE I-95 CORRIDOR WHERE SEA-BREEZE FOCUS WILL BE MAXIMIZED. FOR NOW WILL SHOW A SLIGHT 20% CHANCE FOR THE AFTERNOON SHOWERS TO THE EAST OF THE I-75 CORRIDOR. HIGH TEMPS INTO THE 80S FOR MOST LOCATIONS AWAY FROM THE WATER. && .LONG TERM (MONDAY NIGHT THROUGH NEXT FRIDAY)... THE PERIOD BEGINS WITH ONE UPPER LOW OVER THE SIERRA NEVADA/GREAT BASIN REGION AND A SECOND LOW OVER ONTARIO/QUEBEC...RESULTING IN WESTERLY FLOW ALOFT THE GULF AND FL. AT THE SURFACE A FRONTAL BOUNDARY WAS STRUNG OUT ALONG THE GULF COAST AND SE U.S. AS HIGH PRESSURE RIDGED ACROSS FL FROM THE ATLANTIC TO THE GULF. THROUGH THE REST OF THE WEEK - THE WESTERN LOW BECOMES AN OPEN TROUGH AS IT TRACKS EASTWARD...REACHING THE EASTERN SEABOARD AND EAST GULF LATE FRI. THE SURFACE RIDGE RETREATS EAST ALLOWING THE FRONTAL BOUNDARY TO SAG IN ACROSS THE STATE AND WEAKEN THROUGH WED. MEANWHILE THE APPROACHING UPPER TROUGH FORMS A INVERTED TROUGH/LOW OVER THE WESTERN GULF THAT MOVES NORTHEASTWARD CROSSING THE GULF TO THE SE U.S COASTAL WATERS FRI WITH A COLD FRONT SWEEPING INTO FL. WITH SOME TIMING AND LOCATION DIFFERENCES BETWEEN THE MODELS HAVE OPTED TO MAKE FEW CHANGES TO THE CURRENT FORECAST. CLOUDS ALONG WITH RAIN CHANCES WILL BE INCREASING BUT HAVE KEPT POPS AT 40 PERCENT OR LESS AND JUST SHOWERS FOR NOW. WINDS WILL BE PICKING UP MID AND LATE WEEK BUT THAT WILL BE MORE OF A MARINE ISSUE AND HAVE CAPPED WINDS AROUND 20 KNOTS. TEMPERATURES WILL RUN ABOVE NORMAL ALTHOUGH THEY WILL COOL SLIGHTLY BY WEEKS END. && .AVIATION... VFR CONDITIONS FOR THE NEXT 24 HOURS WITH FEW-SCT CUMULUS UNDER SOME CIRRUS. LIGHT VARIABLE WINDS INCREASE DURING THE MORNING THEN SHIFT TO ONSHORE IN THE AFTERNOON. && .MARINE... HIGH PRESSURE WILL CONTINUE TO RIDGE WESTWARD ACROSS THE EASTERN GULF OF MEXICO THROUGH THE WEEKEND. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH LATER MONDAY...BUT LIKELY WASH OUT BEFORE REACHING THE NORTHERN WATERS ON TUESDAY. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW HEADLINE CRITERIA DURING THE NEXT SEVERAL DAYS. SEA-BREEZE CIRCULATIONS DEVELOPING THIS AFTERNOON AND AGAIN ON SUNDAY AFTERNOON WILL TURN WINDS ONSHORE NEAR THE COAST. && .FIRE WEATHER... ANOTHER DRY DAY ACROSS THE REGION WITH SURFACE HIGH PRESSURE IN CONTROL. MINIMUM RELATIVE HUMIDITY VALUES AWAY FROM THE COAST WILL DROP INTO THE UPPER 20S...WITH UP TO 6 HOUR OF CRITICAL RELATIVE HUMIDITY VALUES POSSIBLE. A DEVELOPING SEA-BREEZE SHOULD HELP TO BRING INCREASED LOW LEVEL MOISTURE TO LOCATIONS CLOSE TO THE COAST DURING THE SECOND HALF OF THE AFTERNOON. A RED FLAG WARNING REMAINS IN EFFECT FOR POLK...HIGHLANDS...AND LEE COUNTIES WHERE RELATIVE HUMIDITY AND ERC VALUES MEET CRITERIA. A SLOW INCREASE IN LOW LEVEL MOISTURE WILL LIKELY PREVENT CRITICAL DURATIONS OF LOW RELATIVE HUMIDITY ON SUNDAY ALTHOUGH A FEW HOURS OF SUB 35 PERCENT READINGS WILL BE POSSIBLE EAST OF THE I-75 CORRIDOR. A FURTHER INCREASE OF LOW LEVEL MOISTURE SHOULD END FIRE WEATHER CONCERNS BY MONDAY. && .PRELIMINARY POINT TEMPS/POPS... TPA 75 58 79 63 / 0 0 0 10 FMY 80 60 85 63 / 0 0 10 10 GIF 79 55 82 61 / 0 0 10 10 SRQ 74 58 78 62 / 0 0 0 10 BKV 77 49 81 57 / 0 10 0 10 SPG 75 62 79 65 / 0 0 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR HIGHLANDS-LEE-POLK. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
920 PM EDT SUN MAR 31 2013 .UPDATE... WEAK CONVERGENCE BOUNDARY SITUATED ACROSS CENTRAL GA THIS EVENING. WV ANALYSIS SHOWS A MID LEVEL SHORTWAVE AXIS MOVING THROUGH CENTRAL AL. THIS FEATURE...ALONG WITH SOME MARGINAL INSTABILITY AT THE SURFACE...HAS HELPED FIRE AND SUSTAIN CONVECTION ACROSS THE SOUTHERN CWFA THIS EVENING. FOR THE PAST HOUR...CONVECTION HAS DECREASED IN INTENSITY AND A LITTLE IN COVERAGE. MADE A FEW UPDATES TO THE ONGOING FORECAST. HAVE REDUCED POPS ACROSS NORTHERN SECTIONS FROM CATEGORICAL TO LIKELY/HIGH END CHANCE. THERE IS VERY LITTLE FORCING ALONG THE CONVERGENCE ZONE ITSELF. MESOSCALE OUTFLOW BOUNDARY ACROSS THE CENTRAL CWFA CONTINUES MOVE NORTH...AND HAS PROVIDED SOME LIFT FOR SCT SHOWERS. ALSO...BUMPED MIN TEMPS UP A FEW DEGREES. && .PREV DISCUSSION... /ISSUED 744 PM EDT SUN MAR 31 2013/ PREV DISCUSSION... /ISSUED 329 PM EDT SUN MAR 31 2013/ SHORT TERM /TONIGHT THROUGH TUESDAY/... SCATTERED SHOWERS WILL BECOME MORE WIDESPREAD THIS EVENING AS THE COLD FRONT MOVES INTO THE TENNESSEE VALLEY. THE ATMOSPHERE AHEAD OF THE FRONT IS TROPICAL IN NATURE AND THE SMALL SHOWERS ARE PUTTING OUT SOME HEAVY RAINFALL. THERE WILL ALSO BE ISOLATED TO SCATTERED THUNDER MIXED IN WITH THE SHOWERS. THE PRECIP WILL END FROM THE NORTHWEST LATE TONIGHT WITH MOST AREAS BECOMING PARTLY SUNNY BY LATE MORNING ON MONDAY. GUIDANCE TEMPS LOOK REASONABLE AND HAVE MADE ONLY MINOR CHANGES TO TEMPS FOR TONIGHT AND MONDAY. /17 LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE LATEST 12Z ECMWF AND GFS MODEL RUNS ARE NOW IN MUCH BETTER AGREEMENT WITH RESPECT TO OVERALL POSITION AND TIMING OF OUR LOW PRESSURE SYSTEM TOWARD END WEEK. BOTH MODELS NOW TRACK THE SURFACE LOW OVER MAINLY SOUTH GA THURSDAY NIGHT... WITH MOST OF THE FORECAST AREA REMAINING IN A COOLER NORTHEAST WEDGE FLOW AT THE SURFACE... RESULTING IN MORE OF A STABLE OVERRUNNING RAIN EVENT FOR THURSDAY AND THURSDAY NIGHT. HOWEVER... APPEARS THAT PARTS OF CENTRAL GA COULD GET IN THE WARM SECTOR THURSDAY EVENING AND OVERNIGHT... WHICH WOULD SUPPORT MORE SURFACE BASED CONVECTION IN THAT AREA. WITH MUCH UNCERTAINTY ON THE PROGRESSION OF THE WARM FRONT NORTHWARD INTO CENTRAL GEORGIA... ALL INTEREST ARE ADVISED TO MONITOR LATER FORECAST CLOSELY FOR POTENTIAL SEVERE WEATHER RISK DEVELOPING ALONG AND SOUTH OF THE WARM FRONT ON THURSDAY AND THURSDAY NIGHT. AT THIS TIME... IT APPEARS THIS EVENT COULD BE MORE OF A HEAVY RAIN EVENT... WHERE 1 TO 3 INCHES OF RAIN LOOKS POSSIBLE OVER THE FORECAST AREA FROM EARLY THURSDAY THROUGH EARLY FRIDAY... WITH THE GREATER AMOUNTS EXPECTED OVER CENTRAL GA WHERE THE HEAVIER...MORE UNSTABLE CONVECTION APPEARS MORE LIKELY TO OCCUR AT THIS TIME. EXPECT TO CLEAR OUT ON FRIDAY WITH HIGH PRESSURE AND DRIER CONDITIONS ON TAP FOR THE WEEKEND. /39 PREVIOUS LONG TERM ... /MONDAY NIGHT THROUGH SATURDAY/ /ISSUED AT 415 AM EDT SUN MAR 31 2013/ 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... 00Z UPDATE... WEAK CONVERGENCE BOUNDARY REMAINS SITUATED ACROSS SOUTH CENTRAL GA THIS EVENING. 500MB ANALYSIS SHOWS A MID LEVEL SHORTWAVE TROUGH AXIS ACROSS WESTERN AL MOVING EAST. THIS FEATURE HAS HELPED FIRE AND SUSTAIN CONVECTION. LATEST HRRR RUN DOES SHOW SHOWERS MOVING IN FROM THE NW OVERNIGHT...WITH THE MID LEVEL TROUGH AXIS. REDUCED CIGS/VSBYS IN SHRA THROUGH 8Z. PATCHY FOG WILL LIKELY DEVELOP WITH VSBYS IN THE 4-6SM RANGE. IFR CIGS WITH RAIN SHOULD HANG AROUND THROUGH SUNRISE. A WIND SHIFT TO THE NW SHOULD OCCUR AROUND 12Z MON. //ATL CONFIDENCE...00Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. NLISTEMAA && .PRELIMINARY POINT TEMPS/POPS... ATHENS 54 75 46 65 / 80 10 10 10 ATLANTA 54 71 50 62 / 80 10 10 10 BLAIRSVILLE 47 67 39 60 / 90 10 20 10 CARTERSVILLE 51 72 43 60 / 80 10 10 10 COLUMBUS 59 77 52 75 / 80 30 5 10 GAINESVILLE 51 72 47 60 / 80 10 10 10 MACON 58 77 48 73 / 80 30 5 10 ROME 50 72 43 60 / 80 10 20 10 PEACHTREE CITY 54 73 45 66 / 80 10 5 10 VIDALIA 60 76 53 77 / 70 60 10 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...LISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
744 PM EDT SUN MAR 31 2013 .PREV DISCUSSION... /ISSUED 329 PM EDT SUN MAR 31 2013/ SHORT TERM /TONIGHT THROUGH TUESDAY/... SCATTERED SHOWERS WILL BECOME MORE WIDESPREAD THIS EVENING AS THE COLD FRONT MOVES INTO THE TENNESSEE VALLEY. THE ATMOSPHERE AHEAD OF THE FRONT IS TROPICAL IN NATURE AND THE SMALL SHOWERS ARE PUTTING OUT SOME HEAVY RAINFALL. THERE WILL ALSO BE ISOLATED TO SCATTERED THUNDER MIXED IN WITH THE SHOWERS. THE PRECIP WILL END FROM THE NORTHWEST LATE TONIGHT WITH MOST AREAS BECOMING PARTLY SUNNY BY LATE MORNING ON MONDAY. GUIDANCE TEMPS LOOK REASONABLE AND HAVE MADE ONLY MINOR CHANGES TO TEMPS FOR TONIGHT AND MONDAY. /17 LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE LATEST 12Z ECMWF AND GFS MODEL RUNS ARE NOW IN MUCH BETTER AGREEMENT WITH RESPECT TO OVERALL POSITION AND TIMING OF OUR LOW PRESSURE SYSTEM TOWARD END WEEK. BOTH MODELS NOW TRACK THE SURFACE LOW OVER MAINLY SOUTH GA THURSDAY NIGHT... WITH MOST OF THE FORECAST AREA REMAINING IN A COOLER NORTHEAST WEDGE FLOW AT THE SURFACE... RESULTING IN MORE OF A STABLE OVERRUNNING RAIN EVENT FOR THURSDAY AND THURSDAY NIGHT. HOWEVER... APPEARS THAT PARTS OF CENTRAL GA COULD GET IN THE WARM SECTOR THURSDAY EVENING AND OVERNIGHT... WHICH WOULD SUPPORT MORE SURFACE BASED CONVECTION IN THAT AREA. WITH MUCH UNCERTAINTY ON THE PROGRESSION OF THE WARM FRONT NORTHWARD INTO CENTRAL GEORGIA... ALL INTEREST ARE ADVISED TO MONITOR LATER FORECAST CLOSELY FOR POTENTIAL SEVERE WEATHER RISK DEVELOPING ALONG AND SOUTH OF THE WARM FRONT ON THURSDAY AND THURSDAY NIGHT. AT THIS TIME... IT APPEARS THIS EVENT COULD BE MORE OF A HEAVY RAIN EVENT... WHERE 1 TO 3 INCHES OF RAIN LOOKS POSSIBLE OVER THE FORECAST AREA FROM EARLY THURSDAY THROUGH EARLY FRIDAY... WITH THE GREATER AMOUNTS EXPECTED OVER CENTRAL GA WHERE THE HEAVIER...MORE UNSTABLE CONVECTION APPEARS MORE LIKELY TO OCCUR AT THIS TIME. EXPECT TO CLEAR OUT ON FRIDAY WITH HIGH PRESSURE AND DRIER CONDITIONS ON TAP FOR THE WEEKEND. /39 PREVIOUS LONG TERM ... /MONDAY NIGHT THROUGH SATURDAY/ /ISSUED AT 415 AM EDT SUN MAR 31 2013/ 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... 00Z UPDATE... WEAK CONVERGENCE BOUNDARY REMAINS SITUATED ACROSS SOUTH CENTRAL GA THIS EVENING. 500MB ANALYSIS SHOWS A MID LEVEL SHORTWAVE TROUGH AXIS ACROSS WESTERN AL MOVING EAST. THIS FEATURE HAS HELPED FIRE AND SUSTAIN CONVECTION. LATEST HRRR RUN DOES SHOW SHOWERS MOVING IN FROM THE NW OVERNIGHT...WITH THE MID LEVEL TROUGH AXIS. REDUCED CIGS/VSBYS IN SHRA THROUGH 8Z. PATCHY FOG WILL LIKELY DEVELOP WITH VSBYS IN THE 4-6SM RANGE. IFR CIGS WITH RAIN SHOULD HANG AROUND THROUGH SUNRISE. A WIND SHIFT TO THE NW SHOULD OCCUR AROUND 12Z MON. //ATL CONFIDENCE...00Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. NLISTEMAA && .PRELIMINARY POINT TEMPS/POPS... ATHENS 54 75 46 65 / 80 10 10 10 ATLANTA 54 71 50 62 / 80 10 10 10 BLAIRSVILLE 47 67 39 60 / 90 10 20 10 CARTERSVILLE 51 72 43 60 / 80 10 10 10 COLUMBUS 59 77 52 75 / 80 30 5 10 GAINESVILLE 51 72 47 60 / 80 10 10 10 MACON 58 77 48 73 / 80 30 5 10 ROME 50 72 43 60 / 80 10 20 10 PEACHTREE CITY 54 73 45 66 / 80 10 5 10 VIDALIA 60 76 53 77 / 70 60 10 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
404 PM CDT SAT MAR 30 2013 ...UPDATED SHORT TERM AND LONG TERM SECTIONS... .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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 215 PM CDT SAT MAR 30 2013 SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS WESTERN KANSAS DURING THE LATE EVENING HOURS. A COLD FRONT WILL MOVE SOUTH TIED TO A SHORTWAVE TROUGH MOVING SOUTHEAST OUT OF NEBRASKA. BEHIND THE FRONT...CEILINGS WILL DEVELOP IN THE MVFR RANGE AND WILL FORECAST 1500 TO 2500 CEILING IN THE 09-15Z TIME FRAME. THERE WILL BE A 2 OR 3 HOUR PERIOD OF FAIRLY STRONG NORTH TO NORTHWEST WINDS IMMEDIATELY BEHIND THE FRONT OF 20 TO 25 KNOTS WITH SOME GUSTS ABOVE 30 KNOTS. && .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...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
216 PM CDT SAT MAR 30 2013 ...UPDATED AVIATION AND SYNOPSIS SECTIONS... .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...(TODAY AND TONIGHT) ISSUED AT 234 AM CDT SAT MAR 30 2013 TODAY: NORTHWESTERLY FLOW ALOFT AND AN EMBEDDED SHORTWAVE TROF WILL MOVE ACROSS THE NORTHERN PRAIRIES AND ACROSS THE CENTRAL PLAINS TODAY. THIS UL FEATURE WILL USHER IN THE PASSAGE FOR A COLD FRONT WITH MUCH DRIER AIR ADVECTING IN ACROSS THE REGION. NNW WINDS WILL STILL BE DOWNSLOPE AND A WARM 850 HPA PLUME WILL ADVECT ACROSS THE REGION, SO TEMPERATURES ARE EXPECTED TO BE WARM. FORECASTING HIGHS IN THE MID TO UPPER 70S DEG F, WHICH IS IN LINE WITH MOS GUIDANCE. TONIGHT: AN AREA OF ENHANCED 800-600 HPA FRONTOGENESIS WILL MOVE ACROSS THE REGION AND COULD RESULT IN A FEW SHOWERS TONIGHT. EVEN THOUGH 500 HPA TEMPERATURES ARE FAIRLY COLD /-20 DEG C/ NOT EXPECTING MUCH INSTABILITY AS THE DRY AIR ADVECTS IN AND THE HIGHER THETA-E AXIS MOVES EAST OF THE REGION. OVERNIGHT LOWS INTO SUNDAY WILL BE COOLER WITH THE DRIER AIRMASS - 30S AND 40S DEG F. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 347 AM CDT SAT MAR 30 2013 A STRONG COLD FRONT IS STILL ADVERTISED TO PUSH SOUTH ACROSS THE CENTRAL HIGH PLAINS LATE SUNDAY NIGHT INTO EARLY MONDAY. THE MEDIUM RANGE MODELS ARE FOR THE MOST PART CONTINUING TO TREND TOWARD A LESSENING IMPACT OF COLD AIR BEHIND THE FRONT. THE CANADIAN AND ECMWF KEEP 850 MB TEMPERATURES ABOVE 0C ON MONDAY WHILE THE GFS IS THE COLDEST WITH BELOW 0C TEMPERATURES SPREADING SOUTH THROUGH NEARLY ALL OF SOUTHWEST KANSAS. HOWEVER, EVEN THIS MODEL IS NOT AS COLD AS IT WAS A FEW DAYS AGO. HAVE BACKED OFF A BIT ON THE MENTION OF SNOW FOR MONDAY...KEEPING IT CONFINED TO THE AREA ALONG AND NORTH OF HIGHWAY 96 DURING THE DAY. WILL KEEP SOME SLIGHT CHANCES FOR RAIN OR SNOW GOING MONDAY NIGHT INTO TUESDAY OVER FAR SOUTHWEST KANSAS AS THE REMAINS OF THE WEST COAST SYSTEM MOVE OUT INTO THE CENTRAL AND SOUTHERN PLAINS. THROUGH THE REMAINDER OF THE EXTENDED PERIOD WE SHOULD SEE WARMER TEMPERATURES RETURN AS UPPER LEVEL RIDGING BUILDS BACK INTO THE CENTRAL PART OF THE COUNTRY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 215 PM CDT SAT MAR 30 2013 SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS WESTERN KANSAS DURING THE LATE EVENING HOURS. A COLD FRONT WILL MOVE SOUTH TIED TO A SHORTWAVE TROUGH MOVING SOUTHEAST OUT OF NEBRASKA. BEHIND THE FRONT...CEILINGS WILL DEVELOP IN THE MVFR RANGE AND WILL FORECAST 1500 TO 2500 CEILING IN THE 09-15Z TIME FRAME. THERE WILL BE A 2 OR 3 HOUR PERIOD OF FAIRLY STRONG NORTH TO NORTHWEST WINDS IMMEDIATELY BEHIND THE FRONT OF 20 TO 25 KNOTS WITH SOME GUSTS ABOVE 30 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... DDC 39 71 35 45 / 40 10 40 40 GCK 38 71 35 44 / 40 10 30 40 EHA 41 71 40 44 / 30 10 30 40 LBL 41 71 42 45 / 30 10 30 40 HYS 38 70 34 44 / 50 10 40 40 P28 47 72 40 46 / 40 10 50 50 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...UMSCHEID SHORT TERM...SUGDEN LONG TERM...GERARD AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1006 AM CDT SAT MAR 30 2013 .UPDATE... ISSUED AT 955 AM CDT SAT MAR 30 2013 UPDATED FORECAST TO REMOVE POPS THIS MORNING ACROSS MUCH OF THE AREA. SCATTERED SHOWERS WILL CONTINUE ACROSS BROWN...NORTHERN JACKSON AND NORTHERN JEFFERSON THROUGH NOON. SHOWERS AND THUNDERSTORMS WILL REDEVELOP AHEAD OF A COLD FRONT ACROSS NORTHEAST AND EAST CENTRAL KS THIS AFTERNOON. IF WE GET INSOLATION LATE THIS MORNING AND DURING THE AFTERNOON HOURS...THE ATMOSPHERE MAY DESTABILIZE ENOUGH DURING THE AFTERNOON HOURS FOR SOME OF THE THUNDERSTORMS TO BECOME STRONG TO POSSIBLY SEVER...WITH THE PRIMARY HAZARD BEING QUARTER SIZE HAIL AND STRONG WIND GUSTS. GARGAN && .SHORT TERM...(TODAY THROUGH SUNDAY) WATER VAPOR IMAGERY SHOWING ONE SHORTWAVE TROUGH OVER NE MOVING SOUTHEAST WITH CONVECTION OUT AHEAD OF IT WITHIN WAA REGIME ACROSS SOUTHERN NE INTO CENTRAL KS. THIS AREA OF CONVECTION WILL CONTINUE TO MOVE EAST AND SOUTHEAST ACROSS THE CWA THROUGH SUNRISE BEFORE DIMINISHING. A COLD FRONT OVER CENTRAL NE WILL MOVE SOUTHEAST ACROSS THE CWA THROUGH THE MIDDAY/AFTERNOON HOURS. IF SUFFICIENT HEATING/DESTABILIZATION IN THE WAKE OF THIS MORNINGS ACTIVITY OCCURS...MUCAPES OF 1500-2000 J/KG ARE POSSIBLE ACROSS THE SOUTHEAST CWA...PRIMARILY ALONG AND SOUTHEAST OF THE I 35 CORRIDOR AT THE TIME OF THE FROPA. IF ANY ISOLATED TO SCATTERED CONVECTION IS ABLE TO REDEVELOP ALONG/AHEAD OF THE FRONT WITHIN THIS ENVIRONMENT...THEY MAY BECOME CAPABLE OF PRODUCING SOME HAIL TO QUARTER SIZE AND STRONG GUSTY WINDS. THIS ACTIVITY WOULD LIKELY EXIT THE FAR SOUTHEAST CWA BY EARLY EVENING...ALTHOUGH MORE POST FRONTAL SHOWERS COULD STILL REDEVELOP FURTHER TOWARDS THE NORTHWEST IN ADVANCE OF THE SHORTWAVE TROUGH CURRENTLY MOVING INTO WY. ANY SHOWERS ASSOCIATED WITH THIS SHOULD DISSIPATE BY MIDNIGHT...LEAVING THE REMAINDER OF NIGHT DRY AND COOLER. SUNDAY STILL LOOKING DRY AND MILD WITH HIGHS GENERALLY 65 TO 70 IN ADVANCE OF THE NEXT MUCH STRONGER COLD FRONT TO THE NORTH. THIS FRONT WILL PASS THROUGH THE CWA NORTH TO SOUTH THROUGH THE EVENING WITH A CHANCE FOR RAIN...THEN A CHANCE FOR RAIN OR SNOW OVERNIGHT INTO MONDAY AS THE COLDER AIR PLUNGES SOUTHWARD. ANY SNOWFALL APPEAR SHOULD PRIMARILY BE UNDER HALF AN INCH AT THIS TIME. THE WINTRY MIX POTENTIAL WILL SHIFT TO THE SOUTHERN CWA THROUGH AFTERNOON THEN END BY EVENING...BUT AGAIN AMOUNTS SHOULD BE VERY LIGHT. 63 .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 955 AM CDT SAT MAR 30 2013* ISSUED AT 955 AM CDT SAT MAR 30 2013 MODELS STILL KEEPING THE NEXT TROUGH IN THE ROCKIES TO THE SOUTH OF THE AREA THROUGH MID WEEK WITH DRY CONDITIONS AND A GRADUAL MODERATION IN TEMPS AS THE AREA GRADUALLY TRANSITIONS FROM NORTHWEST FLOW ALOFT TO A MORE ZONAL FLOW. HIGHS SHOULD RISE FROM NEAR 40 ON MONDAY TO THE 50S BY WEDNESDAY...THEN THE 60S AGAIN BY FRIDAY. LOWS IN THE 20S EARLY IN THE WEEK SHOULD RISE TO NEAR 40 BY FRIDAY. 63 && .AVIATION... LOW CIGS HAVE HAD A HARD TIME MOVING INTO THE TERMINALS AND THINK THE MODELS CONTINUE TO BE TO COOL IN THE BOUNDARY LAYER AND OVERDOING THE RH. OUTSIDE OF SOME LIGHT SHOWERS...THINK CONDITIONS WILL TEND TO BE VFR. ONLY EXCEPTION WOULD BE IF WE CLEAR OUT. THEN THERE COULD BE SOME RADIATIONAL FOG...BUT THINK THE CLOUDS WILL HANG IN UNTIL AFTER SUNRISE. FROPA SHOULD OCCUR IN THE EARLY TO MID AFTERNOON. SOME OF THE HIGH RES SOLUTIONS SHOW SOME WEAK POP UP SHOWERS POSSIBLE UNTIL THE FRONT MOVES THROUGH. THE HRRR SEEMS TO BE DOING THE BEST WITH THIS MORNINGS PRECIP AND TAKES MOST OF THE ACTIVITY EAST OF TOP AND FOE BY 15Z. SO WILL KEEP A DRY FORECAST DUE TO LOW CONFIDENCE IN LOCATION OF ANY ISOLATED SHOWER ACTIVITY THIS AFTERNOON. WOLTERS && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GARGAN SHORT TERM...63 LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
617 AM CDT SAT MAR 30 2013 .DISCUSSION... SEE PREV DISCUSSION. && .AVIATION... LOW CIGS HAVE HAD A HARD TIME MOVING INTO THE TERMINALS AND THINK THE MODELS CONTINUE TO BE TO COOL IN THE BOUNDARY LAYER AND OVERDOING THE RH. OUTSIDE OF SOME LIGHT SHOWERS...THINK CONDITIONS WILL TEND TO BE VFR. ONLY EXCEPTION WOULD BE IF WE CLEAR OUT. THEN THERE COULD BE SOME RADIATIONAL FOG...BUT THINK THE CLOUDS WILL HANG IN UNTIL AFTER SUNRISE. FROPA SHOULD OCCUR IN THE EARLY TO MID AFTERNOON. SOME OF THE HIGH RES SOLUTIONS SHOW SOME WEAK POP UP SHOWERS POSSIBLE UNTIL THE FRONT MOVES THROUGH. THE HRRR SEEMS TO BE DOING THE BEST WITH THIS MORNINGS PRECIP AND TAKES MOST OF THE ACTIVITY EAST OF TOP AND FOE BY 15Z. SO WILL KEEP A DRY FORECAST DUE TO LOW CONFIDENCE IN LOCATION OF ANY ISOLATED SHOWER ACTIVITY THIS AFTERNOON. WOLTERS && .PREV DISCUSSION... /415 AM CDT SAT MAR 30 2013/ WATER VAPOR IMAGERY SHOWING ONE SHORTWAVE TROUGH OVER NE MOVING SOUTHEAST WITH CONVECTION OUT AHEAD OF IT WITHIN WAA REGIME ACROSS SOUTHERN NE INTO CENTRAL KS. THIS AREA OF CONVECTION WILL CONTINUE TO MOVE EAST AND SOUTHEAST ACROSS THE CWA THROUGH SUNRISE BEFORE DIMINISHING. A COLD FRONT OVER CENTRAL NE WILL MOVE SOUTHEAST ACROSS THE CWA THROUGH THE MIDDAY/AFTERNOON HOURS. IF SUFFICIENT HEATING/DESTABILIZATION IN THE WAKE OF THIS MORNINGS ACTIVITY OCCURS...MUCAPES OF 1500-2000 J/KG ARE POSSIBLE ACROSS THE SOUTHEAST CWA...PRIMARILY ALONG AND SOUTHEAST OF THE I 35 CORRIDOR AT THE TIME OF THE FROPA. IF ANY ISOLATED TO SCATTERED CONVECTION IS ABLE TO REDEVELOP ALONG/AHEAD OF THE FRONT WITHIN THIS ENVIRONMENT...THEY MAY BECOME CAPABLE OF PRODUCING SOME HAIL TO QUARTER SIZE AND STRONG GUSTY WINDS. THIS ACTIVITY WOULD LIKELY EXIT THE FAR SOUTHEAST CWA BY EARLY EVENING...ALTHOUGH MORE POST FRONTAL SHOWERS COULD STILL REDEVELOP FURTHER TOWARDS THE NORTHWEST IN ADVANCE OF THE SHORTWAVE TROUGH CURRENTLY MOVING INTO WY. ANY SHOWERS ASSOCIATED WITH THIS SHOULD DISSIPATE BY MIDNIGHT...LEAVING THE REMAINDER OF NIGHT DRY AND COOLER. SUNDAY STILL LOOKING DRY AND MILD WITH HIGHS GENERALLY 65 TO 70 IN ADVANCE OF THE NEXT MUCH STRONGER COLD FRONT TO THE NORTH. THIS FRONT WILL PASS THROUGH THE CWA NORTH TO SOUTH THROUGH THE EVENING WITH A CHANCE FOR RAIN...THEN A CHANCE FOR RAIN OR SNOW OVERNIGHT INTO MONDAY AS THE COLDER AIR PLUNGES SOUTHWARD. ANY SNOWFALL APPEAR SHOULD PRIMARILY BE UNDER HALF AN INCH AT THIS TIME. THE WINTRY MIX POTENTIAL WILL SHIFT TO THE SOUTHERN CWA THROUGH AFTERNOON THEN END BY EVENING...BUT AGAIN AMOUNTS SHOULD BE VERY LIGHT. MODELS STILL KEEPING THE NEXT TROUGH IN THE ROCKIES TO THE SOUTH OF THE AREA THROUGH MID WEEK WITH DRY CONDITIONS AND A GRADUAL MODERATION IN TEMPS AS THE AREA GRADUALLY TRANSITIONS FROM NORTHWEST FLOW ALOFT TO A MORE ZONAL FLOW. HIGHS SHOULD RISE FROM NEAR 40 ON MONDAY TO THE 50S BY WEDNESDAY...THEN THE 60S AGAIN BY FRIDAY. LOWS IN THE 20S EARLY IN THE WEEK SHOULD RISE TO NEAR 40 BY FRIDAY. 63 && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1000 PM EDT SUN MAR 31 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL MOVE ACROSS SOUTHERN VIRGINIA AND NORTHEAST NORTH CAROLINA LATER TONIGHT INTO EARLY MONDAY. WARM AND BREEZY CONDITIONS WILL PREVAIL MONDAY AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT WILL CROSS THE REGION MONDAY NIGHT...FOLLOWED BY MUCH COOLER AND DRY WEATHER TUESDAY AND WEDNESDAY...AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... LATEST WX ANALYSIS DEPICTS A WARM FRONT NORTH OF THE AREA...AND A SFC TROUGH OF LOW PRESSURE (OR A WEAK COLD FRONT) TO THE LEE OF THE MTNS. MODELS SHOW THIS SFC TROUGH SETTING UP OVER FAR SOUTHERN VA AND NE NC LATER TONIGHT AND GIVEN ZONAL/WESTERLY FLOW ALOFT PER LATEST 00Z SOUNDINGS EXPECT THE BOUNDARY TO BE SLOW TO PUSH SOUTH OVERNIGHT. LATEST RADAR SHOWS A FAIR AMOUNT OF SHOWER ACTIVITY ACRS NORTH CENTRAL NC MOVING EAST AND EXPECTED TO AFFECT OUR FAR SOUTHERN VA AND NE NC COUNTIES OVER THE NEXT FEW HRS. HAVE RAISED POPS FOR THE REMAINDER OF THE EVENING/EARLY AM HRS TO HIGH CHANCE OR LIKELY ACRS THESE ZONES. MEANWHILE...SKIES ARE STARTING TO CLEAR OVER NORTHERN PORTIONS OF THE CWA...AND SOME PATCHY FOG IS DEVELOPING. WITH THE LOW LEVEL FLOW GENLY BEING RATHER LIGHT...WILL CONTINUE TO SEE FOG DEVELOPMENT SLOWLY SPREAD SOUTH ALTHOUGH NOT SURE HOW FAR SOUTH IT GETS AS CLOUDS ACRS SOUTHERN ZONES WILL BE SLOW TO CLEAR OVERNIGHT. LATEST RUC AND NAM12 SOUNDINGS SHOW THIS POTENTIAL ESPECIALLY FROM 06-09Z SO HAVE ADDED PATCHY FOG TO PORTIONS OF CENTRAL VA AND THE MD ERN SHORE. LITTLE UPDATE TO OVERNIGHT TEMPERATURE FORECAST...LOWS 40-45 FAR NORTH...45-50 ACRS MOST OF THE CWA AND LOWER 50S IN NE NC WHERE SKIES STAY CLOUDY WITH MORE MIXING THROUGH THE NIGHT. .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID- ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT. WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE COLDER AIR. DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE. PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS THE MID-ATLANTIC TUE AND WED. HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID 30S WELL INLAND. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID- ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT. WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE COLDER AIR. DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE. PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS THE MID-ATLANTIC TUE AND WED. HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID 30S WELL INLAND. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AN UPPER LEVEL TROUGH OF COLDER CANADIAN AIR SLOWLY MOVES ACROSS THE NE CONUS ON THU AS SFC HIGH PRESSURE CROSSES THE MID ATLANTIC STATES. EXPECT MORNING LOWS IN THE 30S (NEAR 40 IMMEDIATE COAST) AND HIGHS IN THE MID TO UPPER 50S (NEAR 50 IMMEDIATE COAST). THE SFC HIGH MOVES OFF THE COAST BY THU NIGHT...CAUSING WINDS TO BECOME ONSHORE/SELY AND ALSO CREATING THE POTENTIAL FOR A COLD AIR WEDGE TO DEVELOP OVER NW PORTIONS OF THE FA. A LOW PRESSURE SYSTEM PASSING ACROSS THE GULF COAST STATES FROM TX TO FL DURING THE MIDDLE OF THE WEEK IS STILL EXPECTED TO LIFT NORTH TWD THE MID ATLANTIC STATES THU NIGHT INTO FRI. IT IS TOO SOON TO DETERMINE THE EXACT TRACK OF THIS SYSTEM OR HOW MUCH IT WILL IMPACT THE REGION DUE TO TIMING/PLACEMENT DIFFERENCES AMONG EXTENDED MODELS. THE GFS IS FASTER/MORE PROGRESSIVE WHILE THE ECMWF IS SLOWER. HAVE CONTINUED A GENERAL INCREASE IN PRECIP DURING THIS TIMEFRAME WITH PRECIP SHUTTING OFF QUICKLY BEHIND THE DEPARTING SYSTEM. P-TYPE APPEARS TO BE ALL RAIN AT THIS TIME REGARDLESS OF MODEL DIFFERENCES. HAVE COOLED TEMPERATURES A FEW DEGREES FOR FRI OVER NW PORTIONS OF THE FA DUE TO THE POSSIBLE COLD AIR WEDGE. HIGH PRESSURE RETURNS TO THE AREA ON SAT...FOLLOWED BY A LOW PRESSURE SYSTEM CROSSING THE UPPER OH VALLEY AND ERN GREAT LAKES REGION ON SUN. THIS SYSTEM IS EXPECTED TO DRAG A COLD FRONT ACROSS THE AREA SUN NIGHT INTO MON...ONLY A SLIGHT CHANCE FOR PRECIP OVER FAR NW COUNTIES OF FA IN VA AND MD ATTM. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... CLOUD CEILINGS HAVE IMPROVED TO MOSTLY VFR ACROSS THE REGION. SATELLITE AND RADAR SHOWING AREA OF RAIN OVER NC MOVG EAST AND LIKELY TO AFFECT ECG AND PSBLY ORF THRU MIDNIGHT. WNDS GENERALLY SW-WSW 5 TO 10 KT TONIGHT. SOME PTCHY FOG STARTING TO DEVELOP IN WESTERN PORTIONS OF THE CWA. WENT WITH 3-4 MILES VISBILITY AND FOG FOR TAF SITES BUT WOULD NOT BE SURPRISED TO GET PERIOD OF IFR OVERNIGHT. EXPECT OCNL -RA TONIGHT FOR ECG WITH CIGS PSBLY DOWN TO MVFR. CONFIDENCE LOW FOR ANY DENSE FOG DEVELOPMENT. FRONTL BNDRY WILL PUSH THRU THE REGION OVERNIGHT AND INTO FAR SE VA/NE NC BY MORNING. WEAK WAVES ALONG THE BNDRY WILL CONT TO BRING CHC OF -RA IN SOUTHERN PORTIONS OVERNIGHT AND FOR ENTIRE CWA MON. EXPECT MVFR/VFR CONDS ON MON WITH CHC OF SCT RAIN THRU THE DAY. ANOTHER FRONT MOVES THRU MON EVENING. HI PRES THEN BUILDS INTO THE REGION FOR TUE AND WED WITH VFR CONDS. && .MARINE... UPDATE...SCA FLAGS FOR SRN CHES BAY ALLOWED TO EXPIRE AT 6 PM EDT THIS EVENING. WINDS HAVE SUBSIDED TO SPEEDS AOB 15 KT. PREVIOUS DISCUSSION...A WARM FRONT WILL SLOWLY LIFT NWD OVER CTRL AND NRN WATERS THROUGH THIS EVENING. A COLD FRONT THEN CROSSES THE WATERS LATER TONIGHT. OCCASIONAL WIND GUSTS OF 20-30 KT MAY BE POSSIBLE DURING THE FRONTAL PASSAGE AND WILL COVER THIS POTENTIAL HAZARD WITH MWW OR SMW HEADLINES IF NEEDED. BEHIND THE COLD FRONT...WINDS TO SWITCH TO THE W. SPEEDS ARE EXPECTED TO REMAIN AOB 15 KT DUE TO LACK OF CAA...THEN BECOME SWLY ON MON AS THE FRONT STALLS OVER THE CAROLINAS. A STRONGER FRONTAL BOUNDARY ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE NE U.S. WILL CROSS THE WATERS OVERNIGHT MON NIGHT INTO TUE...FOLLOWED BY MUCH COLDER AIR THROUGH AT LEAST WED. NW-N WINDS SHOULD AVERAGE AROUND 15-20 KT WITH GUSTS UP TO 30 KT OVER THE BAY AND COASTAL WATERS. BEST CHANCES FOR SCA FLAGS CONTINUE TO BE MON NIGHT WITH THE FIRST SURGE OF COLD AIR/CAA...AND THEN AGAIN ON TUE NIGHT INTO WED MORNING. 12Z MODEL RUNS HAVE BACKED OFF A LITTLE BIT ON THE OVERALL STRENGTH OF WINDS THAT CAN MIX DOWN ON MON NIGHT...AND HAVE DECIDED TO HOLD OFF ON ISSUING SCA HEADLINES ATTM. HIGH PRESSURE THEN BUILDS OVER THE MID ATLANTIC REGION WED INTO WED NIGHT...SLIDING OFF THE COAST ON THU. A MORE ROBUST LOW PRESSURE SYSTEM APPROACHES THE MID ATLANTIC REGION THU NIGHT AND MOVES ACROSS THE WATERS FRI INTO FRI NIGHT. SCA FLAGS WILL LIKELY BE NEEDED FOR THIS SYSTEM AS WELL. STAY TUNED. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...LKB NEAR TERM...LKB/DAP SHORT TERM...DAP LONG TERM...BMD AVIATION...JEF MARINE...BMD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
929 PM EDT SUN MAR 31 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL MOVE ACROSS SOUTHERN VIRGINIA AND NORTHEAST NORTH CAROLINA LATER TONIGHT INTO EARLY MONDAY. WARM AND BREEZY CONDITIONS WILL PREVAIL MONDAY AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT WILL CROSS THE REGION MONDAY NIGHT...FOLLOWED BY MUCH COOLER AND DRY WEATHER TUESDAY AND WEDNESDAY...AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... LATEST WX ANALYSIS DEPICTS A WARM FRONT NORTH OF THE AREA...AND A SFC TROUGH OF LOW PRESSURE (OR A WEAK COLD FRONT) TO THE LEE OF THE MTNS. MODELS SHOW THIS SFC TROUGH SETTING UP OVER FAR SOUTHERN VA AND NE NC LATER TONIGHT AND GIVEN ZONAL/WESTERLY FLOW ALOFT PER LATEST 00Z SOUNDINGS EXPECT THE BOUNDARY TO BE SLOW TO PUSH SOUTH OVERNIGHT. LATEST RADAR SHOWS A FAIR AMOUNT OF SHOWER ACTIVITY ACRS NORTH CENTRAL NC MOVING EAST AND EXPECTED TO AFFECT OUR FAR SOUTHERN VA AND NE NC COUNTIES OVER THE NEXT FEW HRS. HAVE RAISED POPS FOR THE REMAINDER OF THE EVENING TO HIGH CHANCE ACRS THESE ZONES. MEANWHILE...SKIES ARE STARTING TO CLEAR OVER NW PORTIONS OF THE CWA...AND WITH THE LOW LEVEL FLOW GENLY BEING RATHER LIGHT...SHOULD SEE SOME FOG DEVELOPMENT OVER THE NEXT FEW HRS ACRS NORTHERN AREAS. LATEST RUC AND NAM12 SOUNDINGS SHOW THIS POTENTIAL ESPECIALLY FROM 06-09Z SO HAVE ADDED PATCHY FOG TO PORTIONS OF CENTRAL VA AND THE MD ERN SHORE. LITTLE UPDATE TO OVERNIGHT TEMPERATURE FORECAST...LOWS 40-45 FAR NORTH...45-50 ACRS MOST OF THE CWA AND LOWER 50S IN NE NC WHERE SKIES STAY CLOUDY WITH MORE MIXING THROUGH THE NIGHT. .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID- ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT. WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE COLDER AIR. DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE. PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS THE MID-ATLANTIC TUE AND WED. HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID 30S WELL INLAND. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID- ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT. WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE COLDER AIR. DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE. PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS THE MID-ATLANTIC TUE AND WED. HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID 30S WELL INLAND. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AN UPPER LEVEL TROUGH OF COLDER CANADIAN AIR SLOWLY MOVES ACROSS THE NE CONUS ON THU AS SFC HIGH PRESSURE CROSSES THE MID ATLANTIC STATES. EXPECT MORNING LOWS IN THE 30S (NEAR 40 IMMEDIATE COAST) AND HIGHS IN THE MID TO UPPER 50S (NEAR 50 IMMEDIATE COAST). THE SFC HIGH MOVES OFF THE COAST BY THU NIGHT...CAUSING WINDS TO BECOME ONSHORE/SELY AND ALSO CREATING THE POTENTIAL FOR A COLD AIR WEDGE TO DEVELOP OVER NW PORTIONS OF THE FA. A LOW PRESSURE SYSTEM PASSING ACROSS THE GULF COAST STATES FROM TX TO FL DURING THE MIDDLE OF THE WEEK IS STILL EXPECTED TO LIFT NORTH TWD THE MID ATLANTIC STATES THU NIGHT INTO FRI. IT IS TOO SOON TO DETERMINE THE EXACT TRACK OF THIS SYSTEM OR HOW MUCH IT WILL IMPACT THE REGION DUE TO TIMING/PLACEMENT DIFFERENCES AMONG EXTENDED MODELS. THE GFS IS FASTER/MORE PROGRESSIVE WHILE THE ECMWF IS SLOWER. HAVE CONTINUED A GENERAL INCREASE IN PRECIP DURING THIS TIMEFRAME WITH PRECIP SHUTTING OFF QUICKLY BEHIND THE DEPARTING SYSTEM. P-TYPE APPEARS TO BE ALL RAIN AT THIS TIME REGARDLESS OF MODEL DIFFERENCES. HAVE COOLED TEMPERATURES A FEW DEGREES FOR FRI OVER NW PORTIONS OF THE FA DUE TO THE POSSIBLE COLD AIR WEDGE. HIGH PRESSURE RETURNS TO THE AREA ON SAT...FOLLOWED BY A LOW PRESSURE SYSTEM CROSSING THE UPPER OH VALLEY AND ERN GREAT LAKES REGION ON SUN. THIS SYSTEM IS EXPECTED TO DRAG A COLD FRONT ACROSS THE AREA SUN NIGHT INTO MON...ONLY A SLIGHT CHANCE FOR PRECIP OVER FAR NW COUNTIES OF FA IN VA AND MD ATTM. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... CLOUD CEILINGS HAVE IMPROVED TO MOSTLY VFR ACROSS THE REGION. SATELLITE AND RADAR SHOWING AREA OF RAIN OVER NC MOVG EAST AND LIKELY TO AFFECT ECG AND PSBLY ORF THRU MIDNIGHT. WNDS GENERALLY SW-WSW 5 TO 10 KT TONIGHT. SOME PTCHY FOG STARTING TO DEVELOP IN WESTERN PORTIONS OF THE CWA. WENT WITH 3-4 MILES VISBILITY AND FOG FOR TAF SITES BUT WOULD NOT BE SURPRISED TO GET PERIOD OF IFR OVERNIGHT. EXPECT OCNL -RA TONIGHT FOR ECG WITH CIGS PSBLY DOWN TO MVFR. CONFIDENCE LOW FOR ANY DENSE FOG DEVELOPMENT. FRONTL BNDRY WILL PUSH THRU THE REGION OVERNIGHT AND INTO FAR SE VA/NE NC BY MORNING. WEAK WAVES ALONG THE BNDRY WILL CONT TO BRING CHC OF -RA IN SOUTHERN PORTIONS OVERNIGHT AND FOR ENTIRE CWA MON. EXPECT MVFR/VFR CONDS ON MON WITH CHC OF SCT RAIN THRU THE DAY. ANOTHER FRONT MOVES THRU MON EVENING. HI PRES THEN BUILDS INTO THE REGION FOR TUE AND WED WITH VFR CONDS. && .MARINE... UPDATE...SCA FLAGS FOR SRN CHES BAY ALLOWED TO EXPIRE AT 6 PM EDT THIS EVENING. WINDS HAVE SUBSIDED TO SPEEDS AOB 15 KT. PREVIOUS DISCUSSION...A WARM FRONT WILL SLOWLY LIFT NWD OVER CTRL AND NRN WATERS THROUGH THIS EVENING. A COLD FRONT THEN CROSSES THE WATERS LATER TONIGHT. OCCASIONAL WIND GUSTS OF 20-30 KT MAY BE POSSIBLE DURING THE FRONTAL PASSAGE AND WILL COVER THIS POTENTIAL HAZARD WITH MWW OR SMW HEADLINES IF NEEDED. BEHIND THE COLD FRONT...WINDS TO SWITCH TO THE W. SPEEDS ARE EXPECTED TO REMAIN AOB 15 KT DUE TO LACK OF CAA...THEN BECOME SWLY ON MON AS THE FRONT STALLS OVER THE CAROLINAS. A STRONGER FRONTAL BOUNDARY ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE NE U.S. WILL CROSS THE WATERS OVERNIGHT MON NIGHT INTO TUE...FOLLOWED BY MUCH COLDER AIR THROUGH AT LEAST WED. NW-N WINDS SHOULD AVERAGE AROUND 15-20 KT WITH GUSTS UP TO 30 KT OVER THE BAY AND COASTAL WATERS. BEST CHANCES FOR SCA FLAGS CONTINUE TO BE MON NIGHT WITH THE FIRST SURGE OF COLD AIR/CAA...AND THEN AGAIN ON TUE NIGHT INTO WED MORNING. 12Z MODEL RUNS HAVE BACKED OFF A LITTLE BIT ON THE OVERALL STRENGTH OF WINDS THAT CAN MIX DOWN ON MON NIGHT...AND HAVE DECIDED TO HOLD OFF ON ISSUING SCA HEADLINES ATTM. HIGH PRESSURE THEN BUILDS OVER THE MID ATLANTIC REGION WED INTO WED NIGHT...SLIDING OFF THE COAST ON THU. A MORE ROBUST LOW PRESSURE SYSTEM APPROACHES THE MID ATLANTIC REGION THU NIGHT AND MOVES ACROSS THE WATERS FRI INTO FRI NIGHT. SCA FLAGS WILL LIKELY BE NEEDED FOR THIS SYSTEM AS WELL. STAY TUNED. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...LKB NEAR TERM...LKB/DAP SHORT TERM...DAP LONG TERM...BMD AVIATION...JEF MARINE...BMD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
859 PM EDT SUN MAR 31 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL MOVE ACROSS SOUTHERN VIRGINIA AND NORTHEAST NORTH CAROLINA LATER TONIGHT INTO EARLY MONDAY. WARM AND BREEZY CONDITIONS WILL PREVAIL MONDAY AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT WILL CROSS THE REGION MONDAY NIGHT...FOLLOWED BY MUCH COOLER AND DRY WEATHER TUESDAY AND WEDNESDAY...AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... LATEST WX ANALYSIS DEPICTS A WARM FRONT NORTH OF THE AREA...AND A SFC TROUGH OF LOW PRESSURE (OR A WEAK COLD FRONT) TO THE LEE OF THE MTNS. MODELS SHOW THIS SFC TROUGH SETTING UP OVER FAR SOUTHERN VA AND NE NC LATER TONIGHT AND GIVEN ZONAL/WESTERLY FLOW ALOFT PER LATEST 00Z SOUNDINGS EXPECT THE BOUNDARY TO BE SLOW TO PUSH SOUTH OVERNIGHT. LATEST RADAR SHOWS A FAIR AMOUNT OF SHOWER ACTIVITY ACRS NORTH CENTRAL NC MOVING EAST AND EXPECTED TO AFFECT OUR FAR SOUTHERN VA AND NE NC COUNTIES OVER THE NEXT FEW HRS. HAVE RAISED POPS FOR THE REMAINDER OF THE EVENING TO HIGH CHANCE ACRS THESE ZONES. MEANWHILE...SKIES ARE STARTING TO CLEAR OVER NW PORTIONS OF THE CWA...AND WITH THE LOW LEVEL FLOW GENLY BEING RATHER LIGHT...SHOULD SEE SOME FOG DEVELOPMENT OVER THE NEXT FEW HRS ACRS NORTHERN AREAS. LATEST RUC AND NAM12 SOUNDINGS SHOW THIS POTENTIAL ESPECIALLY FROM 06-09Z SO HAVE ADDED PATCHY FOG TO PORTIONS OF CENTRAL VA AND THE MD ERN SHORE. LITTLE UPDATE TO OVERNIGHT TEMPERATURE FORECAST...LOWS 40-45 FAR NORTH...45-50 ACRS MOST OF THE CWA AND LOWER 50S IN NE NC WHERE SKIES STAY CLOUDY WITH MORE MIXING THROUGH THE NIGHT. .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... SOME BRIEF CLEARING WILL TAKE PLACE MONDAY AHEAD OF THE NEXT STRONG COLD FRONT THAT WILL MOVE THROUGH MONDAY NIGHT. THE MAJOR IMPACT OF THIS FRONT WILL BE THE SHOT OF COLDER AIR IT BRINGS TO THE MID- ATLANTIC. DUE TO THE LIMITED MOISTURE AVAILABLE...ONLY A SLIGHT CHANCE/20% FOR A BRIEF PERIOD OF SHOWERS EXPECTED WITH AN AREA OF CONVERGENCE AHEAD OF THE FRONT LATE MON AFTN INTO MONDAY NIGHT. WINDS WILL SHIFT TO THE N/NW BEHIND THE FRONT USHERING IN THE COLDER AIR. DRIER/COOLER AIR WILL BE MAINTAINED THROUGH WED DUE TO MID LEVEL FLOW OUT OF THE WNW-NW AND HIGH PRESSURE MOVING E FROM THE NORTHERN PLAINS KEEPS A PERSISTENT...COOLER W/WNW FLOW AT THE SURFACE. PARTY CLOUDY CONDITIONS WILL PREVAIL DUE SHORT WAVES MOVING ACROSS THE MID-ATLANTIC TUE AND WED. HIGH TEMPS WILL RANGE FROM THE LOWER 70S SOUTH TO MID 60S NORTH FOR MON...COOLING INTO THE LOW TO MID 50S FOR TUE AND WED. LOW TEMPS TUE MORNING WILL BE ~40 ACROSS NE NC AND IN THE LOWER TO MID 30S WELL INLAND. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AN UPPER LEVEL TROUGH OF COLDER CANADIAN AIR SLOWLY MOVES ACROSS THE NE CONUS ON THU AS SFC HIGH PRESSURE CROSSES THE MID ATLANTIC STATES. EXPECT MORNING LOWS IN THE 30S (NEAR 40 IMMEDIATE COAST) AND HIGHS IN THE MID TO UPPER 50S (NEAR 50 IMMEDIATE COAST). THE SFC HIGH MOVES OFF THE COAST BY THU NIGHT...CAUSING WINDS TO BECOME ONSHORE/SELY AND ALSO CREATING THE POTENTIAL FOR A COLD AIR WEDGE TO DEVELOP OVER NW PORTIONS OF THE FA. A LOW PRESSURE SYSTEM PASSING ACROSS THE GULF COAST STATES FROM TX TO FL DURING THE MIDDLE OF THE WEEK IS STILL EXPECTED TO LIFT NORTH TWD THE MID ATLANTIC STATES THU NIGHT INTO FRI. IT IS TOO SOON TO DETERMINE THE EXACT TRACK OF THIS SYSTEM OR HOW MUCH IT WILL IMPACT THE REGION DUE TO TIMING/PLACEMENT DIFFERENCES AMONG EXTENDED MODELS. THE GFS IS FASTER/MORE PROGRESSIVE WHILE THE ECMWF IS SLOWER. HAVE CONTINUED A GENERAL INCREASE IN PRECIP DURING THIS TIMEFRAME WITH PRECIP SHUTTING OFF QUICKLY BEHIND THE DEPARTING SYSTEM. P-TYPE APPEARS TO BE ALL RAIN AT THIS TIME REGARDLESS OF MODEL DIFFERENCES. HAVE COOLED TEMPERATURES A FEW DEGREES FOR FRI OVER NW PORTIONS OF THE FA DUE TO THE POSSIBLE COLD AIR WEDGE. HIGH PRESSURE RETURNS TO THE AREA ON SAT...FOLLOWED BY A LOW PRESSURE SYSTEM CROSSING THE UPPER OH VALLEY AND ERN GREAT LAKES REGION ON SUN. THIS SYSTEM IS EXPECTED TO DRAG A COLD FRONT ACROSS THE AREA SUN NIGHT INTO MON...ONLY A SLIGHT CHANCE FOR PRECIP OVER FAR NW COUNTIES OF FA IN VA AND MD ATTM. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... MANAGED IFR CONDS FOR A PD AT RIC SO FAR...LO PROB FOR SBY IN THE NEXT FEW HRS AS RA CONTS TO MOVE TO THE E REACHING THE CST. OTRW...DRYING EVIDENT ON VSBL IMAGERY ENTERING SRN VA/NE NC W/ ANY CIGS RISING TO 5KFT AND ABV. WNDS BECOMING MORE SSW AS WELL. TRAILING SFC TROUGH TO CROSS THE RGN THIS EVE W/ PSBL SCT-BKN CIGS (GENLY ABV 3KFT) AND PTNTLLY ISOLD/SCT CNVTN. LO PROB FOR MVFR/IFR IN CIGS/FG LT TNGT/ERY MON (AFT RA TDA...AND RELATIVE LGT WNDS AFT MDNGT). VFR CONDS MON AHD OF APPROACHING CDFNT. MDLS CONTG W/ TREND OF DCRSG MSTR ASSOCIATED W/ THAT FNTL PASSAGE MON NGT (TSECTIONS SUGGEST ANY CIGS 5-10KFT). SFC HI PRES BUILDING INTO THE RGN MIDWEEK RESULTS IN VFR CONDS. && .MARINE... UPDATE...SCA FLAGS FOR SRN CHES BAY ALLOWED TO EXPIRE AT 6 PM EDT THIS EVENING. WINDS HAVE SUBSIDED TO SPEEDS AOB 15 KT. PREVIOUS DISCUSSION...A WARM FRONT WILL SLOWLY LIFT NWD OVER CTRL AND NRN WATERS THROUGH THIS EVENING. A COLD FRONT THEN CROSSES THE WATERS LATER TONIGHT. OCCASIONAL WIND GUSTS OF 20-30 KT MAY BE POSSIBLE DURING THE FRONTAL PASSAGE AND WILL COVER THIS POTENTIAL HAZARD WITH MWW OR SMW HEADLINES IF NEEDED. BEHIND THE COLD FRONT...WINDS TO SWITCH TO THE W. SPEEDS ARE EXPECTED TO REMAIN AOB 15 KT DUE TO LACK OF CAA...THEN BECOME SWLY ON MON AS THE FRONT STALLS OVER THE CAROLINAS. A STRONGER FRONTAL BOUNDARY ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE NE U.S. WILL CROSS THE WATERS OVERNIGHT MON NIGHT INTO TUE...FOLLOWED BY MUCH COLDER AIR THROUGH AT LEAST WED. NW-N WINDS SHOULD AVERAGE AROUND 15-20 KT WITH GUSTS UP TO 30 KT OVER THE BAY AND COASTAL WATERS. BEST CHANCES FOR SCA FLAGS CONTINUE TO BE MON NIGHT WITH THE FIRST SURGE OF COLD AIR/CAA...AND THEN AGAIN ON TUE NIGHT INTO WED MORNING. 12Z MODEL RUNS HAVE BACKED OFF A LITTLE BIT ON THE OVERALL STRENGTH OF WINDS THAT CAN MIX DOWN ON MON NIGHT...AND HAVE DECIDED TO HOLD OFF ON ISSUING SCA HEADLINES ATTM. HIGH PRESSURE THEN BUILDS OVER THE MID ATLANTIC REGION WED INTO WED NIGHT...SLIDING OFF THE COAST ON THU. A MORE ROBUST LOW PRESSURE SYSTEM APPROACHES THE MID ATLANTIC REGION THU NIGHT AND MOVES ACROSS THE WATERS FRI INTO FRI NIGHT. SCA FLAGS WILL LIKELY BE NEEDED FOR THIS SYSTEM AS WELL. STAY TUNED. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...LKB NEAR TERM...LKB/DAP SHORT TERM...DAP LONG TERM...BMD AVIATION...ALB MARINE...BMD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
914 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 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 846 PM EDT SUN MAR 31 2013 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. LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS SHOULD PERSIST AT KIWD AND KCMX AS UNSTABLE CONDITIONS REMAIN IN PLACE. WINDS BACKING A BIT MORE TO THE WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT KSAW ON MONDAY. && .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...VOSS MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
723 PM EDT SUN MAR 31 2013 .AVIATION... //DISCUSSION... WELL MIXED WEST-NORTHWEST GRADIENT WILL PERSIST IN ADVANCE OF A COLD FRONT THROUGH THE LATTER HALF OF THE EVENING. INTERMITTENT GUSTS INTO THE 20 KNOT RANGE...WITH GUST FREQUENCY TENDING TO DECREASE WITH TIME COINCIDING WITH THE LOSS OF HEATING. A LOWER STABILITY ENVIRONMENT WILL ALLOW WIDELY SCATTERED LIGHT SHOWERS TO DEVELOP DURING THIS TIME...BUT LIMITED COVERAGE AND DURATION WILL PRECLUDE A MENTION. UPSTREAM RADAR DOES INDICATE A GREATER POTENTIAL FOR A BRIEF PERIOD OF LIGHT PRECIPITATION IN MVFR ACROSS THE NORTHERN TAF SITES AS THE FRONTAL BOUNDARY MOVES THROUGH 03-05Z. OTHERWISE... OBSERVATIONS CONFIRM RECENT MODEL GUIDANCE IN MAINTAINING A CEILING PREDOMINATELY WITHIN LOWER VFR THROUGH THE NIGHT...MVFR CONDITIONS MORE WORTHY OF A TEMPO TO HIGHLIGHT THE MOST LIKELY WINDOW. CEILINGS LIFT INTO THE 5-6K FT RANGE AS DEEPER MIXING ENSUES ON MONDAY. GUSTY NORTHWEST WINDS FOR MONDAY AFTERNOON...PEAK GUST POTENTIAL IN THE 25-28 KNOT RANGE. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET TONIGHT AND MONDAY MORNING. && .PREV DISCUSSION...ISSUED 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. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...UNTIL 10 PM MONDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 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. && $$ AVIATION.....MR SHORT TERM...DRK LONG TERM....SC MARINE.......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
458 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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 134 PM EDT SAT MAR 30 2013 AREA OF PCPN ASSOCIATED WITH LOW PRES TROF HAS SHIFTED E OF KIWD AND WILL SOON BE E OF KCMX. PER SATELLITE IMAGERY AND PER SFC OBS SHOWING INCREASING SFC T/TD SPREADS UPSTREAM...THERE SHOULD BE SUFFICIENT DRYING BEHIND TROF TO ALLOW IFR CONDITIONS TO IMPROVE TO MVFR AND THEN VFR AT KIWD BY LATE AFTN. MEANWHILE...AT KCMX...EXPECT IFR/LIFR CONDITIONS TO IMPROVE TO MVFR LATE IN THE AFTN. APPROACH OF NEXT DISTURBANCE WILL BRING A RETURN TO MVFR CONDITIONS AT KIWD OVERNIGHT. EXPECT INCREASING POTENTIAL OF -SHSN AND CONTINUED MVFR AT KIWD/KCMX LATE TONIGHT/SUN MORNING AS DISTURBANCE ARRIVES. GUSTY WNW WINDS WILL DEVELOP FOLLOWING NEXT SFC TROF PASSAGE LATE MORNING. AT KSAW...IFR/LIFR CONDITIONS WITH -SN/-RA SHOULD IMPROVE TO MVFR LATE AFTN AS PCPN EXITS. DRYING IS MORE UNCERTAIN AT KSAW DUE TO LIGHTER WIND REGIME AND LESS POTENTIAL TO ADVECT DRIER AIR INTO THE AREA. ALTHOUGH WESTERLY WIND WOULD FAVOR DOWNSLOPE DRYING...OPTED TO MAINTAIN MVFR THRU THE EVENING AS WINDS ARE LIGHT. AS WINDS DIMINISH FURTHER OVERNIGHT...MAY SEE IFR CIGS DEVELOP. EXPECT IMPROVEMENT TO MVFR IN THE MORNING UNDER STRENGTHENING CAA. && .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...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
909 PM CDT SUN MAR 31 2013 .UPDATE...THE FORECAST HAS BEEN UPDATED TO REMOVE POPS FOR THE SOUTHEASTERN CWA FOR THE REMAINDER OF THE NIGHT...AS SHWRS AND TSTMS HAVE MOVED EAST OF THE FORECAST AREA. HOURLY TEMPERATURES WERE ALSO SLIGHTLY TWEAKED TO ACCOUNT FOR THE LATEST TRENDS. AREAS OF LOW CLOUDS AND FOG WILL REDEVELOP THIS EVENING WITH AREAS OF DENSE FOG POSSIBLE THROUGH EARLY MONDAY MORNING. /27/ && .AVIATION...AREAS OF IFR/MVFR CLOUDS DECKS WILL CONTINUE THIS EVENING WITH PATCHES OF IFR/LIFR CIG/VSBY IN FOG. LOW CLOUDS AND FOG WILL BE ON THE INCREASE LATER TONIGHT BECOMING WIDESPREAD AFTER MIDNIGHT. FOG WILL CLEAR AND LOW CLOUDS WILL LIFT 13-15Z MONDAY FOR VFR CONDITIONS BY MID MORNING. && PREV 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/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 54 78 49 69 / 10 14 4 20 MERIDIAN 53 77 45 72 / 14 13 4 12 VICKSBURG 54 78 51 68 / 9 14 3 31 HATTIESBURG 60 79 51 74 / 14 22 5 13 NATCHEZ 54 77 54 70 / 10 20 3 28 GREENVILLE 52 75 46 61 / 7 10 3 36 GREENWOOD 51 75 46 65 / 9 10 4 26 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 27/ALLEN
AREA FORECAST DISCUSSION
NWS JACKSON MS
755 PM CDT SUN MAR 31 2013 .UPDATE...THE FORECAST HAS BEEN UPDATED TO REMOVE SEVERE POTENTIAL FOR THE AREA. THE WATCH HAS BEEN CANCELLED AND THE TSTMS HAVE MOVED TO THE EAST OF THE FORECAST AREA. POPS AND CLOUD COVER WAS ALSO ADJUSTED IN THE WAKE OF THE BAND OF STORMS AND TEMPERATURES WERE TWEAKED SLIGHTLY COOLER DUE TO CLEARING SKIES IN THE IMMEDIATE WAKE OF THE RAINFALL. AREAS OF LOW CLOUDS AND FOG WILL REDEVELOP AFTER DARK WITH PATCHES OF DENSE FOG POSSIBLE THROUGH EARLY MONDAY MORNING. && .PREV 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...AREAS OF IFR/MVFR CLOUDS DECKS WILL CONTINUE THIS EVENING WITH ISOLATED LIGHT SHOWERS OVER ERN ZONES THROUGH 9 PM. CLOUDS WILL BE ON THE INCREASE LATER TONIGHT WITH WIDESPREAD IFR CIGS AND PATCHES OF IFR/LIFR VSBYS DUE IN FOG. FOG WILL CLEAR AND LOW CLOUDS WILL LIFTS BY 14Z MONDAY FOR VFR CONDITIONS BY LATE MORNING. && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ ALLEN/15/03
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1213 PM CDT SAT MAR 30 2013 .UPDATE... ISSUED AT 1212 PM CDT SAT MAR 30 2013 STRATUS CONTS TO MIX OUT. ONLY THE FAR SE FRINGE OF THE FCST AREA HAS ANY STRATUS OVC BUT IT IS RAPIDLY THINNING/DISSIPATING. FCST TEMPS WERE RUNNING TOO WARM WHERE STRATUS HAS IMPEDED WARMING. SO MERGED CURRENT OBS WITH THE FCST 3 HRS IN ADVANCE TO GET BACK ON THE TEMP CURVE. DWPTS CONT MUCH HIGHER THAN FCST. SO USED HRRR FOR 18Z AND NAM FOR 21Z/00Z AND INTERPOLATED WITH CURRENT OBS. THE STRATUS WILL CLEAR RESULTING IN A RAPID INCREASE IN TEMPS. GRI IS ALREADY 60F. SO WE MAY NEED TO INCREASE HIGH TEMPS. THE FIRST BATCH OF MID-LEVEL SHWRS WILL BE MOVING INTO VALLEY/GREELEY COUNTIES WITHIN THE HR. AT THIS POINT BELIEVE THE SUB-CLOUD LAYER IS TOO DRY FOR SPRINKLES. CLOUD BASES ARE AVERAGING AROUND 10K FT. THE 4 AM FCST EMPHASIZES SHWR CHANCES OVER THE WRN FRINGE OF THE FCST AREA THIS AFTN. BASED ON CURRENT SATL WE MADE NEED TO RECONFIGURE THEM MORE ACROSS OUR NRN COUNTIES. UPDATE ISSUED AT 915 AM CDT SAT MAR 30 2013 ESTF UPDATE EXTENDED THE DENSE FOG ADVY THRU 16Z BUT WE WERE ABLE TO REMOVE SOME COUNTIES. VIS SATL SHOWS STRATUS/FOG IS SHIFTING S. IT/S THIN AND SUN WARMING THE GROUND AROUND ITS EDGES...EXPECT MIXING WILL DISSIPATE THE FOG/STRATUS BY NO LATER THAN 18Z. SOME ADJUSTMENTS TO SHORT-TERM CLOUDS WERE ALSO MADE. WE MAY NEED TO ADJUST TEMP CURVES AS STRATUS WILL HAMPER HEATING OVER THE NEXT COUPLE HRS. PLEASE SEE UPDATED AVN SECTION. UPDATE ISSUED AT 650 AM CDT SAT MAR 30 2013 AS MENTIONED IN THE SHORT-TERM DISCUSSION BELOW...REMNANT MOISTURE FROM LAST NIGHTS RAIN HAS PROVIDED HIGH DEWPOINTS AND WITH THE LOWER TROPOSPHERE READILY RADIATING OUT...NEAR-ZERO TO ZERO LOW LEVEL DEWPOINT DEPRESSIONS HAVE RESULTED ACROSS MUCH OF THE CWA. IN ADDITION...AS OF 11Z THE SURFACE TROUGH WAS NOTED BISECTING THE CWA FROM NORTHEAST TO SOUTHWEST. THE LOW LEVEL WIND FIELD ACROSS OUR CWA HAS BECOME VERY LIGHT AS A RESULT. THE COMBINATION OF LOW DEWPOINT DEPRESSIONS AND A LIGHT WIND HAS RESULTED IN WIDESPREAD FOG DEVELOPMENT ACROSS THE CWA...WITH MANY LOCATIONS NEAR OR BELOW 1/4SM. THIS FOG SHOULD DIMINISH RAPIDLY POST SUNRISE AS DIABATIC HEATING COMMENCES THUS PROVIDING INCREASING BOUNDARY LAYER HEIGHT AND MIXING. UNTIL THAT TIME HOWEVER...DENSE FOG WILL PERSIST ACROSS MUCH OF THE AREA AND AS A RESULT...WENT AHEAD WITH A DENSE FOG ADVISORY...IN EFFECT UNTIL 14Z...FOR LOCATIONS GENERALLY ALONG AND NORTHWEST OF A LINE FROM OSBORNE TO OSCEOLA. REMAINDER OF THE FORECAST REMAINS IN GOOD SHAPE WITH ONLY MINOR TWEAKS MADE TO HOURLY TEMPERATURE...DEWPOINT AND WIND GRIDS TO BETTER REFLECT CURRENT CONDITIONS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 441 AM CDT SAT MAR 30 2013 OVERNIGHT UPPER AIR ANALYSIS INDICATES NORTHWESTERLY MID AND UPPER LEVEL FLOW OVER THE WESTERN HALF OF THE CONUS...WITH QUASI-ZONAL FLOW PERSISTING ACROSS THE EAST. MID AND UPPER LEVEL FLOW OVER OUR AREA MAXES OUT AT AROUND 55KTS NEAR 200MB PER 00Z SOUNDING DATA FROM KOAX. WATER VAPOR IMAGERY INDICATES A MID LEVEL PERTURBATION MOVING OVER THE CENTRAL PLAINS...WITH ANOTHER MID LEVEL PERTURBATION OVER THE NORTHERN PLAINS. AT THE SURFACE A TROUGH OF LOW BAROMETRIC PRESSURE EXISTS FROM EASTERN SOUTH DAKOTA INTO WESTERN NEBRASKA AND WESTERN KANSAS. THE SYNOPTIC LOW LEVEL WIND FIELD REMAINS FROM THE SOUTHEAST ACROSS OUR CWA AS A RESULT...ALTHOUGH REMNANT OUTFLOW FROM EARLIER CONVECTION HAS DISRUPTED THE SYNOPTIC FLOW AT A FEW LOCATIONS ACROSS OUR CWA. RADAR DATA FROM KUEX INDICATES LINGERING CONVECTION OVER EASTERN NEBRASKA...WITH SOME OF THIS ACTIVITY STILL IMPACTING EXTREME EASTERN PORTIONS OF OUR CWA. REGIONAL RADAR DATA ALSO INDICATES ADDITIONAL CONVECTION ONGOING ACROSS PORTIONS OF CENTRAL AND EASTERN KANSAS. CLOUDY SKIES PERSIST OVER EAST/SOUTHEASTERN PORTIONS OF OUR CWA WHERE CONVECTION IS NEAR AND ALTHOUGH CLEARING SKIES HAVE BEEN NOTED FARTHER WEST/NORTHWEST ACROSS THE AREA...PATCHY FOG IS QUICKLY REPLACING MUCH OF THE CLEARING WHICH HAS BEEN OBSERVED. 0.37" OF RAIN WAS OBSERVED HERE AT THE OFFICE FROM OVERNIGHT CONVECTION...WITH ANYWHERE FROM A FEW TENTHS OF AN INCH TO AROUND A HALF INCH OF RAIN...MAYBE MORE...LIKELY OBSERVED ACROSS MUCH OF THE CWA. REMNANT MOISTURE FROM THIS RAINFALL IS PROVIDING RELATIVELY HIGH SURFACE DEWPOINTS EARLY THIS MORNING...GENERALLY IN THE MID 40S TO LOWER 50S ACROSS OUR CWA. WITH THE AFOREMENTIONED CLEARING SKIES BEHIND THE PRIMARY AREA OF CONVECTION...THE LOWER TROPOSPHERE IS RADIATING OUT VERY QUICKLY THUS RESULTING IN NEAR-ZERO LOW LEVEL DEWPOINT DEPRESSIONS. IN ADDITION THE LOW DEWPOINT DEPRESSION...THE LOW LEVEL WIND FIELD IS ALSO DECREASING IN INTENSITY AS THE SURFACE TROUGH...CURRENTLY OVER WESTERN NEBRASKA AND WESTERN KANSAS...APPROACHES FROM THE WEST. THESE INGREDIENTS ARE PROVIDING THE DEVELOPING FOG WE HAVE NOTICED ACROSS OUR WESTERN CWA THROUGH THE PAST FEW HOURS AND THESE ARE TRENDS WHICH ARE EXPECTED TO CONTINUE THROUGH SUNRISE OR SHORTLY THEREAFTER. GIVEN THIS...WENT AHEAD AND INTRODUCED PATCHY FOG TO THE FORECAST FOR THIS MORNING. MODEL GUIDANCE SUGGESTS DRY CONDITIONS WILL BE OBSERVED ACROSS OUR AREA THROUGH MUCH OF TODAY ONCE THE CURRENT BATCH OF CONVECTION PUSHES OFF TO THE EAST. AS A RESULT...DRY CONDITIONS ARE IN THE FORECAST THROUGH MID AFTERNOON. BY MID TO LATE AFTERNOON HOWEVER...FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR SOUTH/SOUTHEASTERN CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST THE CONVECTIVE TEMPERATURE WILL BE REACHED THUS PROVIDING THE OPPORTUNITY FOR ISOLATED CONVECTION. WENT AHEAD WITH 20% POPS ACROSS OUR SOUTH/SOUTHEAST DURING THE MID AND LATE AFTERNOON HOURS AS A RESULT. IN ADDITION TO THE POSSIBILITY OF AFTERNOON CONVECTION...GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC...AND SREF-MEAN ALL SUGGEST THE MID LEVEL PERTURBATION...CURRENTLY OVER THE NORTHERN PLAINS...WILL CONTINUE MOVING SOUTHEAST AND NEAR OUR AREA LATE THIS AFTERNOON. GUIDANCE CURRENTLY SUGGESTS THERE SHOULD BE JUST ENOUGH LOW TO MID TROPOSPHERIC MOISTURE AND JUST ENOUGH OMEGA...PERHAPS APPROACHING 5-UBAR/S...FOR PRECIPITATION PRODUCTION ACROSS WESTERN PORTIONS OF OUR CWA BEGINNING MID TO LATE THIS AFTERNOON. WENT AHEAD WITH ~20% POPS ACROSS OUR WEST MID TO LATE AFTERNOON AS A RESULT. ANY SURFACE-BASED CONVECTION ACROSS OUR SOUTH/SOUTHEAST SHOULD DIMINISH SHORTLY AFTER SUNSET THIS EVENING AS DIABATIC HEATING IS LOST. PRECIPITATION ACROSS OUR WEST HOWEVER SHOULD SPREAD ACROSS THE SOUTHWESTERN HALF OF OUR CWA TONIGHT AS OMEGA...AHEAD OF THE APPROACHING MID LEVEL PERTURBATION...CONTINUES OVERTAKING THE AREA. TAKING AN EVEN-AVERAGE OF THE NAM...OPERATIONAL GFS...EC...AND SREF-MEAN PROVIDES RAINFALL AMOUNTS OF ~0.05" ACROSS SOUTHWESTERN PORTIONS OF OUR CWA 00Z-06Z AND AS A RESULT...WENT AHEAD WITH 30%-40% POPS ACROSS OUR SOUTHWESTERN CWA 00Z-06Z. PRECIPITATION CHANCES QUICKLY COME TO AN END ACROSS OUR CWA BY 06Z HOWEVER AS THE MID LEVEL PERTURBATION CLEARS THE AREA AND OMEGA IS LOST. DRY CONDITIONS ARE CURRENTLY FORECAST 06Z-12Z. SHOULD AFTERNOON CONVECTION ACROSS OUR SOUTH/SOUTHEAST BE REALIZED...FORECAST PROXIMITY SOUNDINGS...PER THE NAM AND OPERATIONAL GFS...SUGGEST 500 TO 600J/KG 0-1KM MLCAPE WILL BE AVAILABLE FOR UPDRAFT PRODUCTION. NOT OVERLY IMPRESSIVE BUT GIVEN THE LOW FREEZING HEIGHTS TYPICAL THIS TIME OF YEAR...WILL GO AHEAD AND MENTION SMALL HAIL IN THE HWO. IN ADDITION TO THE SMALL HAIL THREAT...FORECAST PROXIMITY SOUNDINGS...IN PARTICULAR FROM THE NAM...SUGGEST DEEP INVERTED-V SOUNDINGS TO AROUND 800MB WILL BE IN EXISTENCE...THUS PRESENTING THE OPPORTUNITY FOR BRIEF GUSTY WINDS. GIVEN THIS THREAT...WILL ALSO MENTION SUB-SEVERE WIND GUSTS IN THE HWO. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 441 AM CDT SAT MAR 30 2013 PRIMARY FORECAST CONCERN FOR THE LONG TERM RESIDES SUNDAY NIGHT AND MONDAY AS A COLD FRONT PUSHES IN FROM THE NORTH ACROSS THE CWA. THE MAIN CHALLENGES DURING THE LONG TERM WILL BE PRECIPITATION AND TEMPERATURES...MAINLY SUNDAY THROUGH MONDAY. PRESSURE RISES ON THE ORDER OF 10 TO 15 MB WILL BE REALIZED BEHIND THE FRONT SUNDAY NIGHT. TEMPERATURES ACROSS THE CWA WILL DROP ROUGHLY 40 DEGREES IN MOST LOCATIONS FROM SUNDAY AFTERNOON TO MONDAY MORNING...BRINGING A COLD REMINDER OF WINTER-LIKE TEMPERATURES TO THE AREA. IN OTHER WORDS...WE WILL GO FROM SLIGHTLY ABOVE NORMAL TEMPERATURES SUNDAY AFTERNOON...TO WELL BELOW NORMAL TEMPERATURES MONDAY WHEN HIGHS ARE FORECAST TO BE AROUND 20 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. NORMAL HIGH TEMPERATURES FOR THIS TIME OF YEAR RANGE FROM THE MID 50S TO THE UPPER 50S...AND NORMAL LOW TEMPERATURES FOR THIS TIME OF YEAR RANGE FROM THE LOWER 30S TO THE MID 30S. 850MB TEMPERATURES ARE TRENDING WARMER INITIALLY BEHIND THE COLD FRONT...SO NOT MUCH SNOW IS EXPECTED AT THE BEGINNING OF THE EVENT. FORECAST SOUNDINGS ARE DEPICTING A RELATIVELY WARM LAYER NEAR THE SURFACE...AND THE REALITY IS THIS LAYER NEAR THE SURFACE WOULD NEED TO COOL MUCH QUICKER TO GET ANY SNOW TO REACH THE SURFACE. GOING TO HOLD OFF ON THE MENTION OF ANY SNOW UNTIL AFTER MIDNIGHT ON SUNDAY. THESE PRECIPITATION CHANCES APPEAR TO BE MOSTLY SYNOPTICALLY DRIVEN. THE RIGHT REAR QUADRANT OF THE UPPER LEVEL JET WILL SET UP OVER THE CWA...AND HENCE AN AREA OF DIVERGENT AIR ALOFT WILL BE REALIZED...HELPING INDUCE RISING AIR BELOW THE JET MONDAY MORNING. HOWEVER...LITTLE TO NO PRECIPITATION IS EXPECTED AFTER 12Z MONDAY. IF ANYTHING...THERE MIGHT BE SOME ACTIVITY ACROSS OUR KANSAS COUNTIES MONDAY MORNING WHERE A SLIGHT CHANCES OF PRECIPITATION WILL EXIST. CONFIDENCE IS PRETTY HIGH REGARDING THE OUTLOOK OF PRECIPITATION AFTER 12Z AS THERE IS GOOD AGREEMENT BETWEEN THE NAM...GFS AND EC. NORTHWESTERLY FLOW ALOFT WILL DOMINATE THE WEATHER PATTERN THROUGH MOST OF THE LONG TERM PERIOD. OUTSIDE OF MONDAY...PRECIPITATION CHANCES ARE LOOKING VERY SLIM. THE LATEST RUN OF THE EC IS NOW HINTING AT SOME POTENTIAL RAINFALL ACROSS THE CWA WEDNESDAY NIGHT THROUGH THURSDAY. HOWEVER...THE GFS DOES NOT HAVE ANYTHING NEAR THE AMOUNT OF COVERAGE OR INTENSITY. SINCE THE LATEST RUN OF THE EC IS VASTLY DIFFERENT THAN THE PREVIOUS RUN...GOING TO LEAVE THIS RAIN MENTION OUT FOR NOW UNTIL SOME CONSISTENCY BECOMES EVIDENT BETWEEN THE MODELS. HIGH TEMPERATURES WILL BE NEAR NORMAL FOR BOTH WEDNESDAY AND THURSDAY. TUESDAY HIGHS...ON THE OTHER HAND...WILL BE ROUGHLY 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. AND LASTLY...FRIDAY AFTERNOON HIGHS WILL BE ABOVE NORMAL...WITH LOCATIONS ACROSS THE SOUTH FLIRTING WITH 70 DEGREES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1212 PM CDT SAT MAR 30 2013 THIS AFTN: VFR WITH A 7-10K FT MID-LEVEL CIGS GRADUALLY INVADING FROM THE NW. N WINDS GUST TO 20 KTS AT TIMES. TNGT: VFR MID-LEVEL CIGS WILL CONT WITH A CHANCE FOR A BRIEF SHWR OR SPRINKLES. AFTER 08Z CLEARING. WINDS DIMINISH TO LESS THAN 10 KTS AND THEN SHIFT TO WNW. SUN THRU 18Z: VFR WITH ESSENTIALLY SKC. NW WINDS AVERAGE 10 KTS. CIG CONFIDENCE: HIGH VSBY CONFIDENCE: HIGH WIND CONFIDENCE: HIGH WX CONFIDENCE: HIGH && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HALBLAUB SHORT TERM...BRYANT LONG TERM...GUERRERO AVIATION...HALBLAUB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1122 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. && .UPDATE... ISSUED AT 817 PM CDT FRI MAR 29 2013 THE SHOWERS AND THUNDERSTORMS HAVE LARGELY MOVED OFF TO THE EAST. GIVEN THE RESIDUAL MOISTURE ALOFT WHICH WILL REMAIN IN PLACE THROUGH SATURDAY EVENING. ISOLATED SHOWERS ARE POSSIBLE THROUGH MIDNIGHT TONIGHT AND THEN AGAIN SATURDAY MORNING WITH SHOWERS AND THUNDERSTORMS POSSIBLE SATURDAY AFTERNOON AS ANOTHER DISTURBANCE MOVES THROUGH IN THE NORTHWEST FLOW ALOFT. A NEW FORECAST IS OUT. && .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 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1122 PM CDT FRI MAR 29 2013 VFR IS GENERALLY EXPECTED OVERNIGHT THROUGH 20Z. THEREAFTER...ANOTHER UPPER LEVEL DISTURBANCE...CURRENTLY ACROSS SCNTL MT...WILL MOVE SOUTHEAST THROUGH WESTERN AND SOUTH CENTRAL NEBRASKA PRODUCING ISOLATED TO SCATTERED SHRA AND TSTM COVERAGE. THESE STORMS ARE EXPECTED TO EXIT THE FCST AREA BY AROUND 03Z. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...CLB LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
739 PM EDT SUN MAR 31 2013 .SYNOPSIS... MILD CONDITIONS AND SCATTERED SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM CAN BE EXPECTED THROUGH MONDAY. THE FIRST OF TWO COLD FRONTS WILL CROSS THE AREA MONDAY MORNING ACCOMPANIED BY SHOWERS. THE SECOND FRONT WILL BE DRY AND MOVE ACROSS THE AREA EARLY TUE. CANADIAN HIGH PRESSURE WILL BRING A RETURN OF CHILLY AIR THROUGH THE MIDDLE OF THE WEEK. UNSETTLED WEATHER WILL ARRIVE FROM THE GULF OF MEXICO THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 645 PM SUNDAY...LATEST KLTX AND SURROUNDING 88DS ILLUSTRATE SCATTERED CONVECTION MOVING ENE AT A GOOD CLIP...WITH ACTIVITY AFFECTING THE WESTERN PORTIONS OF THE ILM CWA AT THE MOMENT. THE PCPN TO CONTINUE ITS TREK EASTWARD THIS EVENING...WITH POPS RE- ORIENTED TO CURRENT ACTIVITY AND ITS PROGRESSION ACROSS THE FA THIS EVENING. A WEAK RESULTANT WIND/SEA BREEZE BOUNDARY HAS PUSHED SLIGHTLY INLAND THIS AFTERNOON AND EVENING...AND WILL PROVIDE A WEAKENING TREND TO THE CONVECTION THAT PUSHES ACROSS IT AND INTO A COOL STABLE MARINE LAYER ALONG THE IMMEDIATE COAST. POPS HAVE BEEN RE-ALIGNED ALONG THE IMMEDIATE COAST FOR THIS EVENING. IN ADDITION...PCPN PROGGED TO DROP SOUTHWARD WITH TIME AS A SFC COLD FRONT SLOWLY SUPPRESSES TO THE SOUTH OVERNIGHT AND MONDAY. LATEST NAM AND HRRR OUTPUT ILLUSTRATE AND BASICALLY CONFIRM THIS INCREASING PCPN COVERAGE AT THE MOMENT...AND CONTINUING OVERNIGHT ACROSS THE FA. CURRENT MIN TEMPS LOOKING AOK WITH VERY LITTLE IF ANY TWEAKING NEEDED AT THIS TIME. PREVIOUS DISCUSSION.............................................. AS OF 3 PM SUNDAY...DEEP AND MODERATE SW FLOW PREVAILS ACROSS THE REGION PRESENTLY AND SO FAR THIS SWIFT FLOW HAS OVERPOWERED AND PREVENTED WHAT MINUSCULE INSTABILITY AND LIFT DOES EXIST FROM BLOSSOMING INTO PRECIPITATING CONVECTION. A FEW LIGHT SHOWERS HAVE FORMED BRIEFLY BUT HAVE BEEN INSIGNIFICANT THUS FAR. ALSO THERE APPEARS TO BE A BIT OF MID-LEVEL DRY AIR INDUCING A WEAK CAP FOR ADDED INHIBITION. TEMPERATURES HAD RISEN INTO THE 70S THIS AFTN AWAY FROM THE IMMEDIATE COAST WHERE CHILLY SEA SFC TEMPS RESIDE. OVERNIGHT IT SEEMS APPARENT THAT COLUMN MOISTURE WILL DEEPEN AND ALL SHORT-RANGE MODELS POINT TO INCREASING CHANCES OF SHOWERS IN SOME DEGREE OR ANOTHER...MOST NOTABLY AFTER MIDNIGHT INTO EARLY MORNING OF MONDAY. SEVERAL NOTEWORTHY PERTURBATIONS ALOFT IN THE WSW FLOW WILL TRACK OVERHEAD LATE TONIGHT...AND OVERALL WE CAN EXPECT UPPER TROUGHING OVER THE REGION TO DEEPEN SLIGHTLY. ALL THESE FACTORS POINT TO AN INCREASING CHANCE OF PCPN AND TONIGHTS FORECAST WILL ADVERTISE LIKELY POP VALUES. EXPECT MILD MINIMUM TEMPERATURES OVERNIGHT GIVEN WINDS AND CLOUD COVER IN A WARM SECTOR REGIME AS A WARM FRONT HAS ALREADY LIFTED WELL NORTH OF THE REGION. IN FACT TEMPERATURE CURVES WILL HOLD PRETTY DARN FLAT FROM LATE EVENING ONWARD. COMPLICATING THIS ARE COLD NEAR-SHORE WATERS IN ONSHORE FLOW TONIGHT...BUT THINK UPPER 50S TO LOWER 60S COASTAL ZONES TO THE MIDDLE AND UPPER 50S INLAND LOOKS GOOD. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...TWO SEPARATE COLD FRONTS ARE SET TO IMPACT THE REGION DURING THE PERIOD. FIRST FRONT WILL BE NEAR THE COAST MON MORNING...SLOWLY PUSHING OFF THE COAST AS THE DAY WEARS ON. EXITING SHORTWAVE AND WEAKLY DIVERGENT FLOW ALOFT...ALONG WITH THE SLOW TO MOVE BOUNDARY AND DIURNAL INSTABILITY WILL KEEP PRECIP CHANCES ELEVATED MON. COAST IS FAVORED OVER INLAND WITH SUBSIDENCE BEHIND EXITING WAVE AND DRY AIR MOVING IN FROM THE NORTH HELPING DRY INLAND AREAS OUT. LOW CLOUD WILL HOLD ON INTO THE AFTERNOON BEFORE DRY AIR ARRIVES. INTERIOR NC WILL CLEAR OUT FIRST FOLLOWED BY INLAND SC AND FINALLY THE COAST. HIGHS WILL BE NEAR TO ABOVE CLIMO MON...LOW TO MID 70S IN MOST AREAS. FIRST FRONT MOVES OFF THE COAST MON NIGHT WITH SKIES CLEARING AND WINDS VEERING FROM WEST-NORTHWEST TO NORTHEAST BU TUE MORNING. RELATIVELY DRY MID LEVELS COMBINED WITH LITTLE FORCING AHEAD OF AND ALONG THE NEXT FRONT. MAY SEE AN INCREASE IN MID CLOUDS WITH THE PASSAGE OF THE FRONT TUE MORNING BUT PRECIP IS NOT ANTICIPATED. ALTHOUGH COLD FRONT WILL BE SOUTH OF THE AREA THE RELATIVELY FLAT UPPER PATTERN KEEPS THE COLDEST AIR TRAPPED TO THE NORTH. TEMPERATURES MON NIGHT SHOULD BE FAIRLY UNIFORM WITH MOST AREAS IN THE UPPER 40S. GRADUAL COLD ADVECTION TUE...INCREASING A LITTLE IN THE AFTERNOON...WILL KEEP HIGHS IN THE MID 60S. WEAK WARM ADVECTION JUST ABOVE THE SURFACE STARTS LATE TUE NIGHT. WITH COLDER AIR IN PLACE THIS IS NOT LIKELY TO HAVE MUCH OF AN IMPACT...THOUGH PORTIONS OF SC MAY RUN A FEW DEGREES WARMER THAN THE REST OF THE FORECAST AREA AS CLOUDS INCREASE. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...SURFACE HIGH PRESSURE WILL RIDGE INTO AREA ON WED FROM SYSTEM OVER THE UPPER MID WEST. THIS HIGH WILL SHIFT EAST OVER THE MID ATLANTIC STATES THROUGH THURS AS A LOW PRESSURE SYSTEM DEVELOPS OVER THE GULF COAST. A SHALLOW COOL AIR MASS FROM THE NORTH WILL REACH INTO THE LOCAL AREA WHILE WARM MOIST AIR WILL BEGIN TO PUSH UP FROM THE SOUTH. SHOULD SQUEEZE OUT A DECENT DAY ON WED BUT MAY SEE SOME CLOUDS DEVELOP AS WARM MOIST LOW LEVEL SW FLOW RUNS OVER THE COOL NE FLOW AT THE SURFACE. PCP WATER VALUES REMAIN AROUND A QUARTER OF INCH OVER NORTHERN TIER ZONES WHILE NORTHEAST SC MAKES IT UP TO AN INCH. CLOUDS AND PCP WILL EVENTUALLY SPREAD NORTH THROUGH WED NIGHT INTO THURS. BY THURS THE HIGH SHIFTS EAST INTO THE ATLANTIC WHILE LOW PRESSURE DEEPENS AS IT SHIFTS EAST OVER THE GULF COAST. OVERALL MOISTURE WILL INCREASE THROUGH THURS WITH PCP WATER VALUES REACHING UP NEAR 1.25 INCHES BY THURS MORNING AND UP TO 1.5 INCHES LATE THURS AND CLOSE TO 1.75 INCHES EARLY FRI. LOOKS LIKE GREATEST QPF WITH THIS EVENT WILL COME THURS NIGHT INTO EARLY FRI AS LOW LIFTS OFF TO THE NORTHEAST TRACKING UP ALONG THE SOUTHEAST COAST. LOW LEVEL WINDS INCREASE OUT OF THE SOUTH UP CLOSE TO 50 KTS BY THURS NIGHT. EXPECT BEST LIFT AND MOISTURE THROUGH THURS NIGHT WITH MODERATE TO HEAVY RAIN POSSIBLE ESPECIALLY AS CONVECTION DEVELOPS ON THE EAST SIDE OF LOW. DEEP NW FLOW WILL DEVELOP ON THE BACK END OF THE LOW PRESSURE SYSTEM AS IT LIFTS RAPIDLY OFF TO THE NORTHEAST THROUGH LATE FRI. THE LOW SHOULD REACH HATTERAS BY FRI AFTERNOON AND THE NEW ENGLAND COAST BY FRI NIGHT. COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN BEHIND IT THROUGH SATURDAY. AIR MASS WILL BEGIN TO MODIFY THROUGH THE WEEKEND AS HIGH PRESSURE CENTER MOVES OVER THE SOUTHEAST WITH RETURN FLOW SETTING UP BY SUNDAY AS THE HIGH SHIFTS OFF THE COAST. AS FOR TEMPS...SHALLOW COOL AIR WILL BE IN PLACE WED INTO THURS WITH TEMPS ONLY REACHING AROUND 60 DEGREES ON WED AND HOLDING IN THE 50S IN PLACES WITH CLOUDS. WINDS WILL COME AROUND TO THE E-SE BRINGING WITH WAA HEADING INTO THURS NIGHT. THIS SHOULD KEEP TEMPS UP CLOSER TO 50 FOR LOWS THURS NIGHT IN CLOUDS AND RAIN. TEMPS SHOULD START OUT WARMER ON FRI BUT ONCE DEEP NW WINDS DEVELOP ON BACK END OF LOW THROUGH FRI AFTN INTO THE EVENING...COOL AIR WILL BRING TEMPS DOWN. OVERNIGHT LOWS SHOULD DROP INTO THE 40S MOST PLACES. COOLING WILL BE BRIEF AS MID TO UPPER RIDGE BUILDS UP THE SOUTHEAST COAST THROUGH SAT WITH H5 HEIGHTS RISING AND LOW LEVEL RETURN FLOW DEVELOPING. OVERALL...LONG TERM PERIOD WILL START OUT COOL WITH OVERNIGHT LOWS IN THE 30S POSSIBLY WED NIGHT BUT WILL END UP WITH SPRING LIKE WEATHER BY THE END OF THE WEEKEND WITH SUNSHINE AND TEMPS IN THE 70S. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 00Z...RADAR IMAGERY SHOWS A LINE OF SHRA/TSRA OVER OUR WESTERN COUNTIES CURRENTLY MOVING THROUGH KFLO. TEMPO MVFR VSBYS ARE CERTAINLY POSSIBLE IN HEAVIER SHOWERS AS THIS LINE MOVES ACROSS OUR CWA THIS EVENING. A WET TAF PERIOD IS IN STORE WITH AN APPROACHING SHORTWAVE AND A WEAK COLD FRONT SAGGING TOWARDS OUR AREA. EXPECT LIGHT TO MODERATE SHOWERS WITH ISO T-STORMS OVERNIGHT THROUGH MONDAY MORNING. VFR CIGS WILL LIKELY PREVAIL TONIGHT...BUT MVFR CIGS COULD DEVELOP MONDAY MORNING IN AREAS THAT RECEIVE MORE PERSISTENT RAINFALL. SOUTHWEST WINDS 8 TO 12 KTS WILL PERSIST FOR MUCH OF THE PERIOD...BECOMING MORE WESTERLY TMRW AFTERNOON. HAVE INCLUDED VCSH INTO THE AFTERNOON HOURS AS THE SFC BOUNDARY MAY LINGER NEAR THE COAST. EXTENDED OUTLOOK...VFR TUESDAY AND WEDNESDAY. SHOWERS AND SUB-VFR CONDITIONS LIKELY THURSDAY AND FRIDAY AS LOW PRESSURE MOVES UP THE ATLANTIC COAST. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 645 PM SUNDAY...WEAK RESULTANT/SEA BREEZE BOUNDARY NOTED BY FINE LINE PUSHING INLAND FROM THE COAST WITH THE 0.5 DEGREE KLTX 88D. THIS HAS RESULTED WITH S TO SSW 15+ KT WINDS NEARSHORE. WITH TIME THIS EVENING AND OVERNIGHT...WINDS WILL RE-ORIENT THEMSELVES BACK TO A SYNOPTIC SW AT 15-25 KT. SSTS IN THE 50S PREVENTING THE 30KT OR STRONGER WIND GUSTS FROM REACHING THE OCEAN SFC ACROSS THE ILM COASTAL WATERS. THE TIGHTENED SFC PG WILL CONTINUE TO SUPPORT THE SUSTAINED 15-25 KT WIND SPEEDS ACROSS THE LOCAL WATERS OVERNIGHT. SIGNIFICANT SEAS PRIMARILY DOMINATED BY THE 5 TO 6 SECOND AVERAGE PERIOD WIND DRIVEN WAVES. OF NOTE...A 1 TO 2 FOOT ESE GROUND SWELL AT 13+ SECOND PERIODS IS AFFECTING THE LOCAL WATERS. OVERALL...LOOKING AT 3 TO 6 FOOT SIGNIFICANT SEAS WITH 7 FOOTERS POSSIBLE ACROSS THE OUTER WATERS OFF CAPE FEAR. PREVIOUS DISCUSSION.............................................. AS OF 3 PM SUNDAY...SMALL CRAFT ADVISORIES WILL REMAIN HOISTED OVERNIGHT FOR ALL WATERS FOR GUSTS TO 25-30 KT AND GENERALLY 3-6 FOOT SEAS AND HIGHEST OFFSHORE. IT APPEARS THE PRESSURE GRADIENT WILL LOOSEN INTO DAYBREAK MONDAY AS A WEAK COLD FRONT SAGS S INTO THE FORECAST AREA FROM THE NW...ALLOWING WINDS TO MELLOW WELL BELOW ADVISORY CRITERIA. SEAS MAY REQUIRE ANOTHER FEW HOURS TO RECOVER AND THE ADVISORIES WILL RUN TO 9AM NC WATERS AND 6AM SC WATERS DUE TO THE BUILDING TREND EXPECTED TONIGHT...HIGHEST SEAS OUTER PORTION AROUND THE FRYING PAN SHOAL. SHORT-CRESTED WAVES DUE TO SHORT WAVE PERIODS/INTERVALS WILL MAKE FOR STEEP WAVES ADDING TO THE WIND HAZARD. ADDITIONALLY MARINERS SHOULD BE AWARE THAT A FEW TSTMS WILL BE FAVORED OVER THE OUTER WATERS AND WEST WALL OF THE GULF STREAM OVERNIGHT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...SOUTHWEST FLOW MON BECOMES WEST-NORTHWEST AS COLD FRONT MOVES SOUTH ACROSS THE WATERS. FRONT WILL BE SLOW TO MOVE WITH OFFSHORE FLOW NOT DEVELOPING UNTIL MON NIGHT. SPEEDS WILL BE 10 TO 15 KT INTO MON AFTERNOON BUT DROP AS BOUNDARY REACHES THE WATERS. WEAK GRADIENT BEHIND THE FRONT AND LACK OF SIGNIFICANT COLD ADVECTION KEEP WINDS 10 KT OR LESS INTO TUE. A SECOND FRONT WILL PUSH SOUTH TUE MORNING...REINFORCING NORTHERLY FLOW. THIS FRONT ALSO LACKS A SIGNIFICANT COLD SURGE WITH PROLONGED STEADY COLD ADVECTION BEHIND IT INSTEAD. SPEEDS WILL NOT INCREASE APPRECIABLY BEHIND THE FRONT. WINDS MAY OCCASIONALLY EXCEED 10 KT BUT OVERALL 10 KT SHOULD BE SUFFICIENT. REDUCTION IN WINDS THROUGH THE PERIOD WILL TRANSLATE TO SEAS FALLING FROM 3 TO 5 FT AT THE START OF THE PERIOD TO 2 TO 4 FT MON NIGHT AND 2 TO 3 FT TUE/TUE NIGHT. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...WINDS WILL VEER AROUND FROM THE N TO THE NE AS HIGH PRESSURE BUILDS INTO THE WATERS WED. IN GENERAL EXPECT WINDS 15 KTS OR LESS AND SEAS 3 FT OR LESS THROUGH WED. BY WED NIGHT INTO THURS HIGH PRESSURE WILL SHIFT OFF SHORE AS LOW PRESSURE DEEPENS OVER THE GULF COAST AND THEN MOVES UP THROUGH THE SOUTHEAST THURS NIGHT INTO FRI. NORTHEAST WINDS WILL INCREASE AND VEER AROUND FROM THE NE TO E WED NIGHT THROUGH THURS AS GRADIENT TIGHTENS BETWEEN THESE TWO SYSTEMS. WINDS WILL EVENTUALLY SHIFT AROUND BECOMING INCREASINGLY ON SHORE THURS NIGHT. SEAS SHOULD REACH UP INTO SCA THRESHOLDS BY THURS AFTN WITH INCREASING ON SHORE WINDS UP TO 25 TO 30 KTS DRIVING SEAS UP TO 4 TO 6 FT NEAR SHORE BY THURS EVENING AND UP TO 9 TO 11 FT OVER THE OUTER WATERS THROUGH THURS NIGHT. WINDS WILL SHIFT AROUND TO THE W-NW THROUGH FRI ON THE BACK END OF THE LOW PRESSURE SYSTEM AS IT LIFTS OFF TO THE NORTHEAST. THIS OFF SHORE FLOW WILL HELP TO LOWER SEAS NEAR SHORE BUT CAA AND TIGHTENED GRADIENT FLOW WILL KEEP SEAS UP NEAR SCA IN OUTER WATERS THROUGH FRI EVENING. BY SAT MORNING WINDS WILL DIMINISH TO 15 KTS OR LESS AND SEAS WILL BE DOWN TO 2 TO 4 FT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 9 AM EDT MONDAY FOR AMZ250-252. && $$ NEAR TERM...DCH/MJC SHORT TERM...III LONG TERM...RGZ AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
727 PM EDT SUN MAR 31 2013 .SYNOPSIS... MILD CONDITIONS AND SCATTERED SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM CAN BE EXPECTED THROUGH MONDAY. THE FIRST OF TWO COLD FRONTS WILL CROSS THE AREA MONDAY MORNING ACCOMPANIED BY SHOWERS. THE SECOND FRONT WILL BE DRY AND MOVE ACROSS THE AREA EARLY TUE. CANADIAN HIGH PRESSURE WILL BRING A RETURN OF CHILLY AIR THROUGH THE MIDDLE OF THE WEEK. UNSETTLED WEATHER WILL ARRIVE FROM THE GULF OF MEXICO THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 645 PM SUNDAY...LATEST KLTX AND SURROUNDING 88DS ILLUSTRATE SCATTERED CONVECTION MOVING ENE AT A GOOD CLIP...WITH ACTIVITY AFFECTING THE WESTERN PORTIONS OF THE ILM CWA AT THE MOMENT. THE PCPN TO CONTINUE ITS TREK EASTWARD THIS EVENING...WITH POPS RE- ORIENTED TO CURRENT ACTIVITY AND ITS PROGRESSION ACROSS THE FA THIS EVENING. A WEAK RESULTANT WIND/SEA BREEZE BOUNDARY HAS PUSHED SLIGHTLY INLAND THIS AFTERNOON AND EVENING...AND WILL PROVIDE A WEAKENING TREND TO THE CONVECTION THAT PUSHES ACROSS IT AND INTO A COOL STABLE MARINE LAYER ALONG THE IMMEDIATE COAST. POPS HAVE BEEN RE-ALIGNED ALONG THE IMMEDIATE COAST FOR THIS EVENING. IN ADDITION...PCPN PROGGED TO DROP SOUTHWARD WITH TIME AS A SFC COLD FRONT SLOWLY SUPPRESSES TO THE SOUTH OVERNIGHT AND MONDAY. LATEST NAM AND HRRR OUTPUT ILLUSTRATE AND BASICALLY CONFIRM THIS INCREASING PCPN COVERAGE AT THE MOMENT...AND CONTINUING OVERNIGHT ACROSS THE FA. CURRENT MIN TEMPS LOOKING AOK WITH VERY LITTLE IF ANY TWEAKING NEEDED AT THIS TIME. PREVIOUS DISCUSSION.............................................. AS OF 3 PM SUNDAY...DEEP AND MODERATE SW FLOW PREVAILS ACROSS THE REGION PRESENTLY AND SO FAR THIS SWIFT FLOW HAS OVERPOWERED AND PREVENTED WHAT MINUSCULE INSTABILITY AND LIFT DOES EXIST FROM BLOSSOMING INTO PRECIPITATING CONVECTION. A FEW LIGHT SHOWERS HAVE FORMED BRIEFLY BUT HAVE BEEN INSIGNIFICANT THUS FAR. ALSO THERE APPEARS TO BE A BIT OF MID-LEVEL DRY AIR INDUCING A WEAK CAP FOR ADDED INHIBITION. TEMPERATURES HAD RISEN INTO THE 70S THIS AFTN AWAY FROM THE IMMEDIATE COAST WHERE CHILLY SEA SFC TEMPS RESIDE. OVERNIGHT IT SEEMS APPARENT THAT COLUMN MOISTURE WILL DEEPEN AND ALL SHORT-RANGE MODELS POINT TO INCREASING CHANCES OF SHOWERS IN SOME DEGREE OR ANOTHER...MOST NOTABLY AFTER MIDNIGHT INTO EARLY MORNING OF MONDAY. SEVERAL NOTEWORTHY PERTURBATIONS ALOFT IN THE WSW FLOW WILL TRACK OVERHEAD LATE TONIGHT...AND OVERALL WE CAN EXPECT UPPER TROUGHING OVER THE REGION TO DEEPEN SLIGHTLY. ALL THESE FACTORS POINT TO AN INCREASING CHANCE OF PCPN AND TONIGHTS FORECAST WILL ADVERTISE LIKELY POP VALUES. EXPECT MILD MINIMUM TEMPERATURES OVERNIGHT GIVEN WINDS AND CLOUD COVER IN A WARM SECTOR REGIME AS A WARM FRONT HAS ALREADY LIFTED WELL NORTH OF THE REGION. IN FACT TEMPERATURE CURVES WILL HOLD PRETTY DARN FLAT FROM LATE EVENING ONWARD. COMPLICATING THIS ARE COLD NEAR-SHORE WATERS IN ONSHORE FLOW TONIGHT...BUT THINK UPPER 50S TO LOWER 60S COASTAL ZONES TO THE MIDDLE AND UPPER 50S INLAND LOOKS GOOD. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...TWO SEPARATE COLD FRONTS ARE SET TO IMPACT THE REGION DURING THE PERIOD. FIRST FRONT WILL BE NEAR THE COAST MON MORNING...SLOWLY PUSHING OFF THE COAST AS THE DAY WEARS ON. EXITING SHORTWAVE AND WEAKLY DIVERGENT FLOW ALOFT...ALONG WITH THE SLOW TO MOVE BOUNDARY AND DIURNAL INSTABILITY WILL KEEP PRECIP CHANCES ELEVATED MON. COAST IS FAVORED OVER INLAND WITH SUBSIDENCE BEHIND EXITING WAVE AND DRY AIR MOVING IN FROM THE NORTH HELPING DRY INLAND AREAS OUT. LOW CLOUD WILL HOLD ON INTO THE AFTERNOON BEFORE DRY AIR ARRIVES. INTERIOR NC WILL CLEAR OUT FIRST FOLLOWED BY INLAND SC AND FINALLY THE COAST. HIGHS WILL BE NEAR TO ABOVE CLIMO MON...LOW TO MID 70S IN MOST AREAS. FIRST FRONT MOVES OFF THE COAST MON NIGHT WITH SKIES CLEARING AND WINDS VEERING FROM WEST-NORTHWEST TO NORTHEAST BU TUE MORNING. RELATIVELY DRY MID LEVELS COMBINED WITH LITTLE FORCING AHEAD OF AND ALONG THE NEXT FRONT. MAY SEE AN INCREASE IN MID CLOUDS WITH THE PASSAGE OF THE FRONT TUE MORNING BUT PRECIP IS NOT ANTICIPATED. ALTHOUGH COLD FRONT WILL BE SOUTH OF THE AREA THE RELATIVELY FLAT UPPER PATTERN KEEPS THE COLDEST AIR TRAPPED TO THE NORTH. TEMPERATURES MON NIGHT SHOULD BE FAIRLY UNIFORM WITH MOST AREAS IN THE UPPER 40S. GRADUAL COLD ADVECTION TUE...INCREASING A LITTLE IN THE AFTERNOON...WILL KEEP HIGHS IN THE MID 60S. WEAK WARM ADVECTION JUST ABOVE THE SURFACE STARTS LATE TUE NIGHT. WITH COLDER AIR IN PLACE THIS IS NOT LIKELY TO HAVE MUCH OF AN IMPACT...THOUGH PORTIONS OF SC MAY RUN A FEW DEGREES WARMER THAN THE REST OF THE FORECAST AREA AS CLOUDS INCREASE. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...SURFACE HIGH PRESSURE WILL RIDGE INTO AREA ON WED FROM SYSTEM OVER THE UPPER MID WEST. THIS HIGH WILL SHIFT EAST OVER THE MID ATLANTIC STATES THROUGH THURS AS A LOW PRESSURE SYSTEM DEVELOPS OVER THE GULF COAST. A SHALLOW COOL AIR MASS FROM THE NORTH WILL REACH INTO THE LOCAL AREA WHILE WARM MOIST AIR WILL BEGIN TO PUSH UP FROM THE SOUTH. SHOULD SQUEEZE OUT A DECENT DAY ON WED BUT MAY SEE SOME CLOUDS DEVELOP AS WARM MOIST LOW LEVEL SW FLOW RUNS OVER THE COOL NE FLOW AT THE SURFACE. PCP WATER VALUES REMAIN AROUND A QUARTER OF INCH OVER NORTHERN TIER ZONES WHILE NORTHEAST SC MAKES IT UP TO AN INCH. CLOUDS AND PCP WILL EVENTUALLY SPREAD NORTH THROUGH WED NIGHT INTO THURS. BY THURS THE HIGH SHIFTS EAST INTO THE ATLANTIC WHILE LOW PRESSURE DEEPENS AS IT SHIFTS EAST OVER THE GULF COAST. OVERALL MOISTURE WILL INCREASE THROUGH THURS WITH PCP WATER VALUES REACHING UP NEAR 1.25 INCHES BY THURS MORNING AND UP TO 1.5 INCHES LATE THURS AND CLOSE TO 1.75 INCHES EARLY FRI. LOOKS LIKE GREATEST QPF WITH THIS EVENT WILL COME THURS NIGHT INTO EARLY FRI AS LOW LIFTS OFF TO THE NORTHEAST TRACKING UP ALONG THE SOUTHEAST COAST. LOW LEVEL WINDS INCREASE OUT OF THE SOUTH UP CLOSE TO 50 KTS BY THURS NIGHT. EXPECT BEST LIFT AND MOISTURE THROUGH THURS NIGHT WITH MODERATE TO HEAVY RAIN POSSIBLE ESPECIALLY AS CONVECTION DEVELOPS ON THE EAST SIDE OF LOW. DEEP NW FLOW WILL DEVELOP ON THE BACK END OF THE LOW PRESSURE SYSTEM AS IT LIFTS RAPIDLY OFF TO THE NORTHEAST THROUGH LATE FRI. THE LOW SHOULD REACH HATTERAS BY FRI AFTERNOON AND THE NEW ENGLAND COAST BY FRI NIGHT. COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN BEHIND IT THROUGH SATURDAY. AIR MASS WILL BEGIN TO MODIFY THROUGH THE WEEKEND AS HIGH PRESSURE CENTER MOVES OVER THE SOUTHEAST WITH RETURN FLOW SETTING UP BY SUNDAY AS THE HIGH SHIFTS OFF THE COAST. AS FOR TEMPS...SHALLOW COOL AIR WILL BE IN PLACE WED INTO THURS WITH TEMPS ONLY REACHING AROUND 60 DEGREES ON WED AND HOLDING IN THE 50S IN PLACES WITH CLOUDS. WINDS WILL COME AROUND TO THE E-SE BRINGING WITH WAA HEADING INTO THURS NIGHT. THIS SHOULD KEEP TEMPS UP CLOSER TO 50 FOR LOWS THURS NIGHT IN CLOUDS AND RAIN. TEMPS SHOULD START OUT WARMER ON FRI BUT ONCE DEEP NW WINDS DEVELOP ON BACK END OF LOW THROUGH FRI AFTN INTO THE EVENING...COOL AIR WILL BRING TEMPS DOWN. OVERNIGHT LOWS SHOULD DROP INTO THE 40S MOST PLACES. COOLING WILL BE BRIEF AS MID TO UPPER RIDGE BUILDS UP THE SOUTHEAST COAST THROUGH SAT WITH H5 HEIGHTS RISING AND LOW LEVEL RETURN FLOW DEVELOPING. OVERALL...LONG TERM PERIOD WILL START OUT COOL WITH OVERNIGHT LOWS IN THE 30S POSSIBLY WED NIGHT BUT WILL END UP WITH SPRING LIKE WEATHER BY THE END OF THE WEEKEND WITH SUNSHINE AND TEMPS IN THE 70S. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 17Z...VFR WITH VCSH. POTENTIAL FOR MVFR/IFR DUE TO LOWERED CIGS AND REDUCED VISIBILITIES IN AREAS OF RAINFALL LATE OVERNIGHT INTO EARLY MONDAY MORNING...IMPROVING TO VFR BY LATE MONDAY MORNING. RAIN FROM EARLIER HAS FOR THE MOST PART TAPERED OFF...WITH CURRENT SATELLITE DEPICTING A FEW BREAKS IN THE CLOUDS UPSTREAM. EXPECT VFR TO PREVAIL...WITH SCATTERED TO MOSTLY CLOUDY SKIES AND SOUTHWEST WINDS INCREASING TO AOB 15 KTS WITH GUSTS UP TO 25 KTS POSSIBLE. AS THE DAY GOES ON...ANTICIPATE POSSIBILITY OF ISOLATED SHOWERS AND EVEN AN ISOLATED THUNDERSTORM BEFORE TONIGHT. INTO THE OVERNIGHT HOURS AND THROUGH MONDAY MORNING...ANTICIPATE SOUTHWEST WINDS AOB 8 KTS WITH SCATTERED SHOWERS AND THE POTENTIAL FOR MVFR/IFR DUE TO LOWERED CIGS. ANY LINGERING RESTRICTIONS WILL GRADUALLY IMPROVE TO VFR BY LATE MONDAY MORNING WITH WEST-NORTHWEST WINDS AOB 10 KTS. EXTENDED OUTLOOK...SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE ON MONDAY. OTHERWISE EXPECT VFR THROUGH EXTENDED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 645 PM SUNDAY...WEAK RESULTANT/SEA BREEZE BOUNDARY NOTED BY FINE LINE PUSHING INLAND FROM THE COAST WITH THE 0.5 DEGREE KLTX 88D. THIS HAS RESULTED WITH S TO SSW 15+ KT WINDS NEARSHORE. WITH TIME THIS EVENING AND OVERNIGHT...WINDS WILL RE-ORIENT THEMSELVES BACK TO A SYNOPTIC SW AT 15-25 KT. SSTS IN THE 50S PREVENTING THE 30KT OR STRONGER WIND GUSTS FROM REACHING THE OCEAN SFC ACROSS THE ILM COASTAL WATERS. THE TIGHTENED SFC PG WILL CONTINUE TO SUPPORT THE SUSTAINED 15-25 KT WIND SPEEDS ACROSS THE LOCAL WATERS OVERNIGHT. SIGNIFICANT SEAS PRIMARILY DOMINATED BY THE 5 TO 6 SECOND AVERAGE PERIOD WIND DRIVEN WAVES. OF NOTE...A 1 TO 2 FOOT ESE GROUND SWELL AT 13+ SECOND PERIODS IS AFFECTING THE LOCAL WATERS. OVERALL...LOOKING AT 3 TO 6 FOOT SIGNIFICANT SEAS WITH 7 FOOTERS POSSIBLE ACROSS THE OUTER WATERS OFF CAPE FEAR. PREVIOUS DISCUSSION.............................................. AS OF 3 PM SUNDAY...SMALL CRAFT ADVISORIES WILL REMAIN HOISTED OVERNIGHT FOR ALL WATERS FOR GUSTS TO 25-30 KT AND GENERALLY 3-6 FOOT SEAS AND HIGHEST OFFSHORE. IT APPEARS THE PRESSURE GRADIENT WILL LOOSEN INTO DAYBREAK MONDAY AS A WEAK COLD FRONT SAGS S INTO THE FORECAST AREA FROM THE NW...ALLOWING WINDS TO MELLOW WELL BELOW ADVISORY CRITERIA. SEAS MAY REQUIRE ANOTHER FEW HOURS TO RECOVER AND THE ADVISORIES WILL RUN TO 9AM NC WATERS AND 6AM SC WATERS DUE TO THE BUILDING TREND EXPECTED TONIGHT...HIGHEST SEAS OUTER PORTION AROUND THE FRYING PAN SHOAL. SHORT-CRESTED WAVES DUE TO SHORT WAVE PERIODS/INTERVALS WILL MAKE FOR STEEP WAVES ADDING TO THE WIND HAZARD. ADDITIONALLY MARINERS SHOULD BE AWARE THAT A FEW TSTMS WILL BE FAVORED OVER THE OUTER WATERS AND WEST WALL OF THE GULF STREAM OVERNIGHT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...SOUTHWEST FLOW MON BECOMES WEST-NORTHWEST AS COLD FRONT MOVES SOUTH ACROSS THE WATERS. FRONT WILL BE SLOW TO MOVE WITH OFFSHORE FLOW NOT DEVELOPING UNTIL MON NIGHT. SPEEDS WILL BE 10 TO 15 KT INTO MON AFTERNOON BUT DROP AS BOUNDARY REACHES THE WATERS. WEAK GRADIENT BEHIND THE FRONT AND LACK OF SIGNIFICANT COLD ADVECTION KEEP WINDS 10 KT OR LESS INTO TUE. A SECOND FRONT WILL PUSH SOUTH TUE MORNING...REINFORCING NORTHERLY FLOW. THIS FRONT ALSO LACKS A SIGNIFICANT COLD SURGE WITH PROLONGED STEADY COLD ADVECTION BEHIND IT INSTEAD. SPEEDS WILL NOT INCREASE APPRECIABLY BEHIND THE FRONT. WINDS MAY OCCASIONALLY EXCEED 10 KT BUT OVERALL 10 KT SHOULD BE SUFFICIENT. REDUCTION IN WINDS THROUGH THE PERIOD WILL TRANSLATE TO SEAS FALLING FROM 3 TO 5 FT AT THE START OF THE PERIOD TO 2 TO 4 FT MON NIGHT AND 2 TO 3 FT TUE/TUE NIGHT. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...WINDS WILL VEER AROUND FROM THE N TO THE NE AS HIGH PRESSURE BUILDS INTO THE WATERS WED. IN GENERAL EXPECT WINDS 15 KTS OR LESS AND SEAS 3 FT OR LESS THROUGH WED. BY WED NIGHT INTO THURS HIGH PRESSURE WILL SHIFT OFF SHORE AS LOW PRESSURE DEEPENS OVER THE GULF COAST AND THEN MOVES UP THROUGH THE SOUTHEAST THURS NIGHT INTO FRI. NORTHEAST WINDS WILL INCREASE AND VEER AROUND FROM THE NE TO E WED NIGHT THROUGH THURS AS GRADIENT TIGHTENS BETWEEN THESE TWO SYSTEMS. WINDS WILL EVENTUALLY SHIFT AROUND BECOMING INCREASINGLY ON SHORE THURS NIGHT. SEAS SHOULD REACH UP INTO SCA THRESHOLDS BY THURS AFTN WITH INCREASING ON SHORE WINDS UP TO 25 TO 30 KTS DRIVING SEAS UP TO 4 TO 6 FT NEAR SHORE BY THURS EVENING AND UP TO 9 TO 11 FT OVER THE OUTER WATERS THROUGH THURS NIGHT. WINDS WILL SHIFT AROUND TO THE W-NW THROUGH FRI ON THE BACK END OF THE LOW PRESSURE SYSTEM AS IT LIFTS OFF TO THE NORTHEAST. THIS OFF SHORE FLOW WILL HELP TO LOWER SEAS NEAR SHORE BUT CAA AND TIGHTENED GRADIENT FLOW WILL KEEP SEAS UP NEAR SCA IN OUTER WATERS THROUGH FRI EVENING. BY SAT MORNING WINDS WILL DIMINISH TO 15 KTS OR LESS AND SEAS WILL BE DOWN TO 2 TO 4 FT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 9 AM EDT MONDAY FOR AMZ250-252. && $$ SYNOPSIS... NEAR TERM...DCH/MJC SHORT TERM...III LONG TERM...RGZ AVIATION...BJR MARINE...
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
847 PM CDT SUN MAR 31 2013 .DISCUSSION... MADE A FEW MINOR TWEAKS TO TEMPERATURES BUT NO REALLY MAJOR CHANGES FOR THE EVENING UPDATE. HIGH PRESSURE CONTINUES TO EXTEND FROM SASKATCHEWAN INTO THE DAKOTAS. STRATOCU HAS MOSTLY DISSIPATED AFTER SUNSET AS EXPECT...ALTHOUGH SAT LOOP SHOWS A FEW LINGERING CLOUDS OVER THE EASTERN CWA. CONTINUE TO SEEM ON TRACK FOR A CLEAR AND COLD NIGHT. MOST MOS GUIDANCE KEEPS US IN THE POSITIVE DIGITS...BUT THE GEM AND RAP DROP US TO NEAR -10 IN SOME SPOTS. THINK THIS IS OVERDONE GIVEN THE DEW POINTS UPSTREAM...BUT EVEN THE SREF HAS SOME LOCATIONS DROPPING TO AROUND 5 BELOW ZERO. LEANED A BIT ON THE COLDER SIDE AND DROPPED LOWS ANOTHER DEGREE OR SO. THINK THAT WINDS WILL STAY UP AROUND 5 KTS AND FOG WILL STAY WEST OF THE AREA...BUT WILL KEEP AN EYE ON ANYTHING DEVELOPING. && .AVIATION... VFR CONDITIONS WILL RETURN TO ALL THE TAF SITES IN THE NEXT HOUR OR SO AS STRATOCU CONTINUES TO DISSIPATE. CLEAR SKIES AND DECREASING NORTHWEST WINDS TO AROUND 10 KTS WILL BE FOUND ACROSS MOST OF THE AREA. SOME STRATOCU REDEVELOPMENT TOMORROW AFTERNOON WILL BE POSSIBLE TOWARDS THE END OF THE PERIOD. && .PREV DISCUSSION... /ISSUED 238 PM CDT SUN MAR 31 2013/ SHORT TERM... MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE TEMPS. MODELS IN FAIR AGREEMENT ON DETAILS SO WILL USE A MODEL BLEND. TONIGHT...QUITE A BIT OF STRATOCU DEVELOPED ALONG AND EAST OF THE RED RIVER VALLEY BY LATE MORNING AND EARLY AFTERNOON. EXPECT MOST OF THIS TO FADE AWAY WITH LOSS OF DAYTIME HEATING LEAVING MOST OF THE AREA MOSTLY CLEAR TONIGHT. NORTH/NORTHWEST WINDS ARE STILL FAIRLY BRISK AND WOULD ALSO EXPECT THESE TO DROP OFF SLOWLY THIS EVENING. THIS SETS THE STAGE FOR A COLD NIGHT AGAIN. UNDER SIMILAR CIRCUMSTANCES LAST WEEK THE TOWNER/BENSON COUNTY AREA DROPPED DOWN INTO THE FIVE BELOW TO TEN BELOW ZERO RANGE. HOWEVER IT IS NOW ALMOST APRIL SO IT DOES NOT SEEM LOGICAL THAT LOWS CAN STILL DROP THAT LOW. EVEN SO WILL UNDERCUT MOST GUIDANCE AND GO WITH SUBZERO TEMPS AROUND THE KDVL REGION. THIS AREA HAS ALSO EXPERIENCED QUITE A BIT OF FOG RECENTLY BUT HAVE MY DOUBTS ABOUT TONIGHT. STIFF NORTHWEST FLOW AND LITTLE MELTING TODAY ARE NOT GREAT CONTRIBUTORS TO FOG SO WILL LET THE NEXT SHIFT TAKE ANOTHER LOOK AT THAT. MON-WED...SHOULD BASICALLY BE LOOKING AT CONTINUED SFC HIGH PRESSURE THROUGHOUT THE MON-TUE NIGHT TIME FRAME WITH NO PCPN EXPECTED. SHOULD SEE A LITTLE BIT OF WARMING FOR DAYTIME HIGHS FROM MON INTO TUE. MODELS ADVERTISING THE BEST CHANCE OF WARMER TEMPS FOR WED WITH MODELS SHOWING 850MB TEMPS RISING BACK ABOVE ZERO. NEXT SHOT OF PCPN COMES ON WED AS THE MAIN SFC LOW TRACKS ACROSS SOUTHERN CANADA. FRONTAL BOUNDARY DOES PUSH ACROSS THE AREA WITH SLIGHTLY BETTER CHANCES FOR PCPN BEING ALONG AND NORTH OF HIGHWAY 200. AT THIS POINT PCPN TYPE LOOKS TO BE RAIN BUT COULD BE A MIX IN THE MORNING. LONG TERM (WED NIGHT-SUN)... A POTENTIALLY ACTIVE PATTERN MAY DEVELOP BY NEXT FRIDAY INTO SUNDAY. TEMPS SHOULD REMAIN BELOW NORMAL WITH THE COLDEST DAY ON THU WITH HIGH PRESSURE. ON FRI...A HYBRID SYSTEM SHOULD SPREAD MOSTLY SNOW INTO THE SOUTHERN 2/3 OF THE AREA...WITH PERHAPS SOME RAIN MIXING IN. THE GFS AND LATEST INDICATIONS OF THE OTHER DETERMINISTIC MODELS WOULD INDICATE ACCUMULATING SNOW IS POSSIBLE FRIDAY NIGHT INTO SAT. THIS COULD DELAY THE LARGE SCALE SPRING MELTING A BIT FURTHER IF LATEST TRENDS CONTINUE...ALTHOUGH THERE ARE DIFFERENCES AFTER THU SO STAY TUNED. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ JR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
359 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 /19Z SATURDAY THROUGH THURSDAY/... LOCATIONS OF GREATEST CONFIDENCE FOR SHRA WILL BE KCVG/KLUK WITH BEING ON THE NORTHERN FRINGE OF TONIGHTS SHORTWAVE PUSHING ACROSS THE TN/CUMBERLAND VALLEYS. CARRIED THUNDER IN THE 10-13Z TIMEFRAME...THOUGH CONFIDENCE NOT WITH THE LATEST MODEL RUNS. WOULD STILL EXPECT PERIOD OF MVFR CIGS MAINLY AT KDAY/KCVG/KLUK AND POSSIBLY KILN CLOSER TO THE SOUTHERN STREAM S/WV. SECONDARY WAVE SWINGING ACROSS NORTHERN AREA MAY NOT HAVE AS MUCH OF AN EFFECT ON TAF SITES AS CURRENT MODELS PLACE BEST CHANCE FOR PRECIPITATION FURTHER NORTH THAN TAF SITES. AS A RESULT...MVFR LIMITED TO MAINLY THE SOUTHERN SYSTEM FROM THE 10Z-15Z TIMEFRAME...WITH WESTERLY WINDS BECOMING A LITTLE MORE GUSTY AFTER 20Z. OUTLOOK...MVFR CONDITIONS AGAIN ON MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...HICKMAN AVIATION...JDR
AREA FORECAST DISCUSSION
NWS TULSA OK
1225 PM CDT SAT MAR 30 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. MORNING ROUND OF SHOWERS AND STORMS EXITING THIS MORNING WITH GENERALLY VFR CONDITIONS IN ITS WAKE...BUT SOME MVFR CEILINGS MAY LINGER AN HOUR OR SO OVER WESTERN ARKANSAS. SOME ADDITIONAL THUNDERSTORMS MAY DEVELOP LATE IN THE AFTERNOON TOWARD 00Z WITH AN INCREASE TONIGHT AS A COLD FRONT PUSHES THROUGH 06-12Z. WHILE PREVAILING CONDITIONS SHOULD REMAIN JUST ABOVE VFR LEVELS...A PERIOD OF MVFR OR EVEN IFR CONDITIONS WITHIN THAT TIME FRAME IS LIKELY AS THE FRONT PASSES. CONDITIONS WILL IMPROVE FROM THE NORTH AFTER 12Z. && .PREV DISCUSSION... /ISSUED 1026 AM CDT SAT MAR 30 2013/ DISCUSSION... SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS EAST CENTRAL OK AND NORTHWEST AR THIS MORNING BUT CONTINUE TO DECREASE IN INTENSITY AS THEY SHIFT SOUTHEAST. EXPECT THIS ROUND TO MOVE OUT OF THE FORECAST AREA AROUND 19-20Z WITH ENOUGH BREAKS IN CLOUDS TO SEND TEMPS WELL INTO 70S ACROSS MUCH OF EASTERN OK...AND REMAINING A BIT COOLER IN FAR EASTERN AREAS. RE-DEVELOPMENT OF STORMS ALONG ANY BOUNDARIES THIS AFTERNOON APPEARS QUESTIONABLE...THOUGH CERTAINLY NOT A ZERO CHANCE IN UNSTABLE AND WEAKLY CAPPED ENVIRONMENT. HAVE UPDATED POPS BASED ON RADAR TRENDS FOR THE MORNING AND HAVE REDUCED THEM SOME FOR THE AFTERNOON ACROSS WESTERN AREAS. ALSO KNOCKED A FEW DEGREES OFF FORECAST HIGHS IN FAR NW ARKANSAS. PREV DISCUSSION... /ISSUED 623 AM CDT SAT MAR 30 2013/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. VARIABLE SKY CONDITIONS WILL PERSIST THROUGH THE MORNING HOURS...WITH AREAS OF MVFR/IFR CIGS MAINLY ACROSS SOUTHEAST OK AND WEST CENTRAL AR. LOCALIZED LOWER CIGS/VSBYS WILL OCCUR WITH SHOWERS/THUNDERSTORMS THROUGH THE MORNING HOURS. SOME IMPROVEMENT IS EXPECTED INTO THE AFTERNOON...WITH AREAS OF SHOWERS/THUNDERSTORMS DEVELOPING AGAIN BY LATE AFTERNOON OR EARLY EVENING. PREV DISCUSSION... /ISSUED 457 AM CDT SAT MAR 30 2013/ DISCUSSION... WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING. SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT HAIL PRODUCERS OVERNIGHT. IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z. QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR WILL BE CAPABLE OF LARGE HAIL PRODUCTION. CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER. SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED RIVER. NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY. WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP. MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK. GW && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...99 LONG TERM....99 AVIATION...14
AREA FORECAST DISCUSSION
NWS TULSA OK
1026 AM CDT SAT MAR 30 2013 .DISCUSSION... SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS EAST CENTRAL OK AND NORTHWEST AR THIS MORNING BUT CONTINUE TO DECREASE IN INTENSITY AS THEY SHIFT SOUTHEAST. EXPECT THIS ROUND TO MOVE OUT OF THE FORECAST AREA AROUND 19-20Z WITH ENOUGH BREAKS IN CLOUDS TO SEND TEMPS WELL INTO 70S ACROSS MUCH OF EASTERN OK...AND REMAINING A BIT COOLER IN FAR EASTERN AREAS. RE-DEVELOPMENT OF STORMS ALONG ANY BOUNDARIES THIS AFTERNOON APPEARS QUESTIONABLE...THOUGH CERTAINLY NOT A ZERO CHANCE IN UNSTABLE AND WEAKLY CAPPED ENVIRONMENT. HAVE UPDATED POPS BASED ON RADAR TRENDS FOR THE MORNING AND HAVE REDUCED THEM SOME FOR THE AFTERNOON ACROSS WESTERN AREAS. ALSO KNOCKED A FEW DEGREES OFF FORECAST HIGHS IN FAR NW ARKANSAS. && .PREV DISCUSSION... /ISSUED 623 AM CDT SAT MAR 30 2013/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. VARIABLE SKY CONDITIONS WILL PERSIST THROUGH THE MORNING HOURS...WITH AREAS OF MVFR/IFR CIGS MAINLY ACROSS SOUTHEAST OK AND WEST CENTRAL AR. LOCALIZED LOWER CIGS/VSBYS WILL OCCUR WITH SHOWERS/THUNDERSTORMS THROUGH THE MORNING HOURS. SOME IMPROVEMENT IS EXPECTED INTO THE AFTERNOON...WITH AREAS OF SHOWERS/THUNDERSTORMS DEVELOPING AGAIN BY LATE AFTERNOON OR EARLY EVENING. PREV DISCUSSION... /ISSUED 457 AM CDT SAT MAR 30 2013/ DISCUSSION... WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING. SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT HAIL PRODUCERS OVERNIGHT. IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z. QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR WILL BE CAPABLE OF LARGE HAIL PRODUCTION. CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER. SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED RIVER. NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY. WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP. MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK. GW && .PRELIMINARY POINT TEMPS/POPS... TUL 77 51 73 43 / 90 60 10 10 FSM 73 56 74 48 / 70 60 30 10 MLC 75 55 73 48 / 70 60 30 10 BVO 76 46 72 40 / 40 50 10 10 FYV 67 51 70 42 / 100 70 20 0 BYV 65 49 69 41 / 90 70 10 0 MKO 75 54 72 46 / 60 60 20 10 MIO 71 47 71 42 / 90 60 0 10 F10 76 54 72 47 / 50 60 20 10 HHW 74 57 72 53 / 50 60 60 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...14
AREA FORECAST DISCUSSION
NWS TULSA OK
623 AM CDT SAT MAR 30 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. VARIABLE SKY CONDITIONS WILL PERSIST THROUGH THE MORNING HOURS...WITH AREAS OF MVFR/IFR CIGS MAINLY ACROSS SOUTHEAST OK AND WEST CENTRAL AR. LOCALIZED LOWER CIGS/VSBYS WILL OCCUR WITH SHOWERS/THUNDERSTORMS THROUGH THE MORNING HOURS. SOME IMPROVEMENT IS EXPECTED INTO THE AFTERNOON...WITH AREAS OF SHOWERS/THUNDERSTORMS DEVELOPING AGAIN BY LATE AFTERNOON OR EARLY EVENING. && .PREV DISCUSSION... /ISSUED 457 AM CDT SAT MAR 30 2013/ DISCUSSION... WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING. SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT HAIL PRODUCERS OVERNIGHT. IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z. QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR WILL BE CAPABLE OF LARGE HAIL PRODUCTION. CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER. SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED RIVER. NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY. WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP. MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK. GW && .PRELIMINARY POINT TEMPS/POPS... TUL 77 51 73 43 / 50 60 10 10 FSM 73 56 74 48 / 80 60 30 10 MLC 75 55 73 48 / 50 60 30 10 BVO 76 46 72 40 / 40 50 10 10 FYV 69 51 70 42 / 90 70 20 0 BYV 67 49 69 41 / 90 70 10 0 MKO 75 54 72 46 / 60 60 20 10 MIO 71 47 71 42 / 70 60 0 10 F10 76 54 72 47 / 50 60 20 10 HHW 74 57 72 53 / 60 60 60 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...18
AREA FORECAST DISCUSSION
NWS TULSA OK
457 AM CDT SAT MAR 30 2013 .DISCUSSION... WAVE TRAIN ROLLING ALONG IN NORTHWEST FLOW HAULING CLUSTERS OF SHOWERS AND THUNDERSTORMS THIS MORNING. SOME OF THE STRONGER THUNDERSTORMS PROVED EFFICIENT HAIL PRODUCERS OVERNIGHT. IN THE SHORT TERM FOLLOWED HRRR MODEL WHICH HAS BEEN GOOD LAST SIX HOURS WITH CONVECTIVE ACTION. BULK OF CURRENT PRECIP EAST OF NORTHWEST AR ZONES AROUND 18Z. QUESTION THEN BECOMES WHAT BOUNDARIES ARE LEFT BEHIND TO FIRE LATE AFTERNOON..OR EVENING. TEMPERATURES INTO THE MID 70S THIS AFTERNOON..IN ADVANCE OF A WEAK COOL FRONTAL BOUNDARY SAGGING INTO THE FORECAST AREA WILL LIKELY IGNITE ANOTHER ROUND OF THUNDER. CAPE VALUES IN THE 2000 J/KG NEIGHBORHOOD AND SUFFICIENT SHEAR WILL BE CAPABLE OF LARGE HAIL PRODUCTION. CONVECTION MIGRATING SOUTHEAST OVERNIGHT LEAVING MOST AREAS NORTH OF INTERSTATE 40 WITH A DRY WARM EASTER. SHOWERS THUNDER MOST LIKELY NEAR OR SOUTH OF THE RED RIVER. NEXT WAVE AND REAL COLD FRONT ARRIVE SOMETIME MONDAY. WRF VERY FAST AND THE OUTLIER IN BRINGING IN THE COLD AIR COMPARED TO MOST OF THE OTHER MODELS. RESULTING WRF MOS BASED MAX TEMPS SOME 15 TO 20 DEGREES COLDER FOR NORTHERN LOCATIONS. USED FOUR MODEL MAX TEMP. MODEL DIFFERENCES CONTINUE TO PLAGUE THE MIDWEEK TIME PERIOD. ECMWF CONSISTENT WITH ITSELF BRINGING AN UPPER LOW DIRECTLY OVER FORECAST AREA. MEANWHILE GFS WEAKER DRIER... MORE PROGRESSIVE WITH THE FEATURE. ECMWF TOO GOOD TO TOTALLY IGNORE..CHANCE POPS MIDWEEK. GW && .PRELIMINARY POINT TEMPS/POPS... TUL 77 51 73 43 / 50 60 10 10 FSM 73 56 74 48 / 80 60 30 10 MLC 75 55 73 48 / 50 60 30 10 BVO 76 46 72 40 / 40 50 10 10 FYV 69 51 70 42 / 90 70 20 0 BYV 67 49 69 41 / 90 70 10 0 MKO 75 54 72 46 / 60 60 20 10 MIO 71 47 71 42 / 70 60 0 10 F10 76 54 72 47 / 50 60 20 10 HHW 74 57 72 53 / 60 60 60 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...18 LONG TERM....21
AREA FORECAST DISCUSSION...CORRECTED
NWS MEDFORD OR
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 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 SHOWER 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 && .AVIATION...VFR CONDITIONS WILL CONTINUE INTO TONIGHT. HIGH AND MID LEVEL CLOUDS WILL GRADUALLY INCREASE IN THE AFTERNOON WITH LIGHT TO MODERATE EAST TO NORTHEAST WINDS ALOFT VEERING TO SOUTHERLY. THE AIR MASS WILL DESTABILIZE LATE THIS THE AFTERNOON WITH SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE OVER THE MOUNTAINS OF SISKIYOU COUNTY. TEMPORARY MVFR CIGS ARE POSSIBLE EARLY SUNDAY MORNING IN THE ROGUE VALLEY AND UMPQUA BASIN WITH PARTIAL MOUNTAIN OBSCURATIONS. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PACIFIC COASTAL WATERS...NONE. $$ CC
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
949 AM EDT SAT MAR 30 2013 .DISCUSSION... LOW LEVEL MOISTURE APPEARS TO BE TRAPPED IN THE TN VALLEY. WITH VERY WEAK FLOW FROM THE SURFACE TO 850 MB...THE CLOUDS WILL PROBABLY BE SLOWER TO CLEAR THAN MODELS INDICATE. EXPECT THAT CLEARING WILL NOT COME UNTIL AROUND 18Z OR LATER BASED ON THE LATEST RUC SOUNDINGS. THIS WILL AFFECT TEMPS...SO THE UPDATE WILL MAKE SOME DOWNWARD ADJUSTMENTS. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DGS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1224 PM EDT SAT MAR 30 2013 .SYNOPSIS... HIGH PRESSURE ACROSS THE REGION WILL GRADUALLY SHIFT EAST AND OFFSHORE THIS AFTERNOON INTO TONIGHT. THIS WILL RESULT IN MILDER TEMPERATURES AHEAD OF A COLD FRONT THAT WILL BRING A CHANCE OF RAIN SHOWERS LATER TONIGHT INTO SUNDAY. ANOTHER COLD FRONT SHOULD PROVIDE A RETURN TO COLDER CONDITIONS DURING NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1210 PM EDT SATURDAY... ADJUSTED CLOUD COVER TO AC/CU FIELDS IN THE MOUNTAINS. MODIFIED TEMPERATURES AND RAISE HIGH TEMPERATURES A FEW DEGREES ESPECAILLY IN THE SOUTHEAST. WAITING TO SEE IF ANY SHOWERS DEVELOP THIS AFTERNOON ACROSS THE HIGHER TERRAIN. AS OF 943 AM EDT SATURDAY... THIS MORNING 8AM/12Z RNK SOUNDING DISPLAYED AN INVERSION AROUND 910MB WITH A POCKET OF MOISTURE ABOUT 720 MB AND A WEST TO NORTHWEST FLOW. HIGH PRESSURE OVER OHIO THIS MORNING WILL TRAVEL EAST TODAY INTO TONIGHT. THIS WILL RESULT IN PLEASANT WEATHER THIS AFTERNOON FOR OUR REGION WITH SEASONABLE TEMPERATURES. RNK WRFARW AND HRRR SUPPORT THE MENTION OF ISOLATED SHOWERS ACROSS SOUTHWEST PORTIONS OF CWA THIS AFTERNOON AND EVENING. THE MAIN AREA OF RAIN ASSOCIATED WITH THE WARM FRONT ON TRACK TO DEVELOP OVERNIGHT. MADE SOME MINOR MODIFICATIONS TO TEMPERATURES...CLOUD COVER AND POPS FOR TODAY. AS OF 252 AM EDT SATURDAY... WARMING TREND CONTINUES OVER THE NEXT 24 HOURS AS HIGH PRESSURE ACROSS THE REGION THIS MORNING GRADUALLY SHIFTS EAST AND OFFSHORE ALLOWING A WEAK WARM ADVECTION PATTERN TO TAKE SHAPE. WILL HAVE A WEAK IMPULSE PASSING TO THE SOUTH EARLY THIS MORNING BEFORE THE AREA WORKS INTO A WEAK SUBSIDENCE REGION BETWEEN THE RIDGE AND A WARM FRONT TO THE SW THIS AFTERNOON. THIS LOOKS TO HELP DIMINISH CLOUDS IN ALL AREAS EXCEPT PERHAPS THE FAR SW WHERE SOME MOISTURE MAY GET STUCK FROM THE NW NC RIDGES INTO SW VA. MAY ALSO LEAVE IN THE GOING ISOLATED -RA MENTION IN NW NC EARLY BEFORE DEEPER MOISTURE EXITS WITH MORE OF AN AC TO CU FIELD ELSW THIS AFTERNOON. LATEST MODEL THICKNESS COMBO WITH WEAK SW FLOW AND BASED ON MORE INSOLATION SUPPORTS HIGHS LOW/MID 60S BLUE RIDGE EAST TODAY...AND MID/UPPER 50S WEST OUTSIDE OF THE HIGHER ELEVATIONS. WARM FRONT AND ASSOCIATED WEAK VORT AXIS WILL APPROACH FROM THE SW OVERNIGHT HELPING TURN THE LOW LEVEL FLOW MORE SE THIS EVENING AHEAD OF THE MAIN BODY OF DEEPER MOISTURE/SHRA THAT WILL BE NEARING THE WEST SHORTLY AFTER MIDNIGHT. MODELS REMAIN RATHER CONSISTENT IN SHOWING A SWATH OF BETTER LIFT ACROSS THE NW CLOSER TO THE MAIN SHORTWAVE AXIS...AND ALONG THE SRN BLUE RIDGE WHERE AIDED BY WEAK UPSLOPE AND PERHAPS A SECONDARY BAGGY WAVE ALONG THE WARM FRONT LATE. THIS INITIAL UPSLOPE FLOW SUPPORTS GOING A BIT FASTER WITH POPS OVERNIGHT WITH ALL EXCEPT THE EASTERN THIRD SEEING LIKELY/CAT POPS BY DAYBREAK. CANT TOTALLY RULE OUT A RUMBLE OF THUNDER ESPCLY SW GIVEN DECENT LIFT AND PUNCH OF WARM AIR COMING IN WITH AN INCREASING 85H JET LIKELY WITH WHATS LEFT OF AN EARLIER MCS. HOWEVER GIVEN FCST LOW LEVEL STABILITY WONT INCLUDE FOR NOW. HEAVIEST QPF THRU DAWN LOOKS TO BE OVER THE FAR WEST WITH AROUND A QUARTER TO ONE HALF INCH POSSIBLE ESPCLY WHERE ENHANCED BY WEAK UPSLOPE AND SOME EMBEDDED CONVECTION ALOFT. LOW TEMPS SHOULD BE MUCH MILDER THAN SEEN IN A WHILE WITH UPPER 30S TO MID 40S...WITH PERHAPS A FEW VALLEYS AND EASTERN SPOTS A BIT COLDER EARLY ON BEFORE RISING LATE AS CLOUDS/SHRA ARRIVE. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... AS OF 315 AM EDT SATURDAY... A WARM FRONT WILL SPREAD A QUICK SHOT OF RAIN ACROSS THE REGION DURING THE FIRST HALF OF SUNDAY. THE COLD FRONT HOLDS TO THE NW LONG ENOUGH SO THAT MONDAY WILL FEATURE MANY HIGHS IN THE 60S WITH H85 TEMPS FROM +4C TO +8C. ALTHOUGH ITS BEEN SAID WAY TOO MANY TIMES THIS MARCH...THE COLD SHOT ARRIVING MONDAY NIGHT THROUGH TUESDAY MAY BE WINTER`S LAST GASP...WITH -10C AT H85 ONCE AGAIN TOUCHING SE WEST VA. ALTHOUGH THE OP GFS IS GENERATING LIGHT SNOW ACROSS MOSTLY GREENBRIER MONDAY NIGHT...ALL OTHER MODELS SAY NO...AND ARE MUCH DRIER AT H85 AND H7. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 115 PM EDT FRIDAY... COLDER AIR PUSHING IN WITH STRONG CANADIAN HIGH MOVING SE INTO THE PLAINS. THIS HIGH MOVES INTO THE OHIO VALLEY BY WEDNESDAY AND SHIFTS EAST OF US THURSDAY. TEMPS WILL AGAIN BE FALLING WELL BELOW NORMAL WITH HIGHS TUE-WED IN THE UPPER 30S TO MID 40S MTNS...AND MID 40S TO LOWER 50S EAST. FOR THE THU NIGHT-FRI TIME FRAME...THE 00Z ECMWF SHOWS THE NEXT SHORTWAVE PUSHING INTO THE OHIO VALLEY SOUTH TO THE GULF COAST. MEANWHILE...THE 12Z GFS IS FASTER AND FURTHER SOUTH WITH ITS SYSTEM KEEPING PRECIP MORE OVER THE SOUTHEAST. THE ECMWF WORKS A WARM FRONT AND LOW NE TO THE AREA FRIDAY WITH RAIN...AND RETREATING HIGH PRESSURE. LEANED THE FORECAST TOWARD A WETTER SOLUTION SIMILAR TO THE ECMWF. SHOULD BE MAINLY RAIN BUT CANNOT RULE OUT SOME WINTRY PRECIP IF THE COLD AIR IS SLOW TO DISLODGE. BOTH MODELS AFTER FRIDAY CLOSE OFF AN UPPER LOW ALONG THE EAST COAST...DELMARVA AREA FOR ECMWF AND EAST OF SOUTH CAROLINA FOR THE GFS. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... AS OF 1205 PM EDT SATURDAY... EXPECT GOOD FLYING CONDITIONS TO PREVAIL IN MOST AREAS INTO/THROUGH EARLY THIS EVENING BEFORE THE APPROACH OF A WARM FRONT BRINGS AN INCREASING THREAT OF SHOWERS ALONG WITH FLIGHT RESTRICTIONS BACK INTO MVFR OR IFR RANGE LATER TONIGHT INTO MUCH OF SUNDAY. LOOKS LIKE MOST OF THE RAINFALL WILL AFFECT THE WESTERN TAF LOCATIONS SUCH AS KBLF/KBCB SHORTLY AFTER MIDNIGHT...AND THEN PROGRESS NORTH/EAST OVER THE REMAINDER OF THE FORECAST POINTS BY DAYBREAK. COULD SEE CIGS/VSBYS RAPIDLY LOWER AS WELL AROUND DAWN ON SUNDAY AS A PERIOD OF MODERATE TO HEAVY RAIN TRACKS ACROSS PARTS OF THE AREA AS WELL. AN ISOLATED THUNDERSTORM IS POSSIBLE. BECAUSE OF THE LIMITED COVERAGE...LEFT OUT OF TAFS FOR NOW. PASSAGE OF THE WARM FRONT EARLY AND SUBSEQUENT COLD FRONT LATER IN THE DAY SHOULD BRING END TO RAIN THREAT ALONG WITH CLEARING SKIES IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE BY LATE SUNDAY AFTERNOON. HOWEVER TYPICAL UPSLOPING CLOUDS..AND POSSIBLY SOME ISOLATED SHOWERS SHOULD MAINTAIN A THREAT FOR AT LEAST OCCASIONAL MVFR CEILINGS THROUGH SUNDAY NIGHT ACROSS SOUTHEASTERN WV TERMINAL FORECAST POINTS. APPROACH OF MUCH MORE POTENT COLD FRONT WILL MAINTAIN MVFR TO POSSIBLY IFR RESTRICTIONS WITH INCREASING THREAT OF PRECIPITATION ACROSS UPSLOPE AREAS OF THE WEST LATER MONDAY INTO MONDAY NIGHT. EXPECT VFR CONDITIONS EAST OF THE BLUE RIDGE TO BE OVERTAKEN BY AT LEAST MVFR RESTRICTIONS MONDAY NIGHT INTO TUESDAY MORNING AS COLD FRONT AND ASSOCIATED PRECIPITATION MOVE EAST THROUGH THE AREA. PROLONGED PERIOD OF COLD UPSLOPING WINDS AND SNOW SHOWERS WILL AGAIN MAINTAIN MVFR TO OCCASIONAL IFR RESTRICTIONS TO WESTERN FLANKS OF THE APPALACHIANS TUESDAY THROUGH WEDNESDAY...BUT WITH A RETURN TO VFR WEATHER EXPECTED IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE FOLLOWING FRONTAL PASSAGE TUESDAY AFTERNOON CONTINUING INTO WEDNESDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WP NEAR TERM...JH/KK SHORT TERM...KM LONG TERM...WP AVIATION...JH/KK/WERT
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1008 AM EDT SAT MAR 30 2013 .SYNOPSIS... HIGH PRESSURE ACROSS THE REGION WILL GRADUALLY SHIFT EAST AND OFFSHORE THIS AFTERNOON INTO TONIGHT. THIS WILL RESULT IN MILDER TEMPERATURES AHEAD OF A COLD FRONT THAT WILL BRING A CHANCE OF RAIN SHOWERS LATER TONIGHT INTO SUNDAY. ANOTHER COLD FRONT SHOULD PROVIDE A RETURN TO COLDER CONDITIONS DURING NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 943 AM EDT SATURDAY... THIS MORNING 8AM/12Z RNK SOUNDING DISPLAYED AN INVERSION AROUND 910MB WITH A POCKET OF MOISTURE ABOUT 720 MB AND A WEST TO NORTHWEST FLOW. HIGH PRESSURE OVER OHIO THIS MORNING WILL TRAVEL EAST TODAY INTO TONIGHT. THIS WILL RESULT IN PLEASANT WEATHER THIS AFTERNOON FOR OUR REGION WITH SEASONABLE TEMPERATURES. RNK WRFARW AND HRRR SUPPORT THE MENTION OF ISOLATED SHOWERS ACROSS SOUTHWEST PORTIONS OF CWA THIS AFTERNOON AND EVENING. THE MAIN AREA OF RAIN ASSOCIATED WITH THE WARM FRONT ON TRACK TO DEVELOP OVERNIGHT. MADE SOME MINOR MODIFICATIONS TO TEMPERATURES...CLOUD COVER AND POPS FOR TODAY. AS OF 252 AM EDT SATURDAY... WARMING TREND CONTINUES OVER THE NEXT 24 HOURS AS HIGH PRESSURE ACROSS THE REGION THIS MORNING GRADUALLY SHIFTS EAST AND OFFSHORE ALLOWING A WEAK WARM ADVECTION PATTERN TO TAKE SHAPE. WILL HAVE A WEAK IMPULSE PASSING TO THE SOUTH EARLY THIS MORNING BEFORE THE AREA WORKS INTO A WEAK SUBSIDENCE REGION BETWEEN THE RIDGE AND A WARM FRONT TO THE SW THIS AFTERNOON. THIS LOOKS TO HELP DIMINISH CLOUDS IN ALL AREAS EXCEPT PERHAPS THE FAR SW WHERE SOME MOISTURE MAY GET STUCK FROM THE NW NC RIDGES INTO SW VA. MAY ALSO LEAVE IN THE GOING ISOLATED -RA MENTION IN NW NC EARLY BEFORE DEEPER MOISTURE EXITS WITH MORE OF AN AC TO CU FIELD ELSW THIS AFTERNOON. LATEST MODEL THICKNESS COMBO WITH WEAK SW FLOW AND BASED ON MORE INSOLATION SUPPORTS HIGHS LOW/MID 60S BLUE RIDGE EAST TODAY...AND MID/UPPER 50S WEST OUTSIDE OF THE HIGHER ELEVATIONS. WARM FRONT AND ASSOCIATED WEAK VORT AXIS WILL APPROACH FROM THE SW OVERNIGHT HELPING TURN THE LOW LEVEL FLOW MORE SE THIS EVENING AHEAD OF THE MAIN BODY OF DEEPER MOISTURE/SHRA THAT WILL BE NEARING THE WEST SHORTLY AFTER MIDNIGHT. MODELS REMAIN RATHER CONSISTENT IN SHOWING A SWATH OF BETTER LIFT ACROSS THE NW CLOSER TO THE MAIN SHORTWAVE AXIS...AND ALONG THE SRN BLUE RIDGE WHERE AIDED BY WEAK UPSLOPE AND PERHAPS A SECONDARY BAGGY WAVE ALONG THE WARM FRONT LATE. THIS INITIAL UPSLOPE FLOW SUPPORTS GOING A BIT FASTER WITH POPS OVERNIGHT WITH ALL EXCEPT THE EASTERN THIRD SEEING LIKELY/CAT POPS BY DAYBREAK. CANT TOTALLY RULE OUT A RUMBLE OF THUNDER ESPCLY SW GIVEN DECENT LIFT AND PUNCH OF WARM AIR COMING IN WITH AN INCREASING 85H JET LIKELY WITH WHATS LEFT OF AN EARLIER MCS. HOWEVER GIVEN FCST LOW LEVEL STABILITY WONT INCLUDE FOR NOW. HEAVIEST QPF THRU DAWN LOOKS TO BE OVER THE FAR WEST WITH AROUND A QUARTER TO ONE HALF INCH POSSIBLE ESPCLY WHERE ENHANCED BY WEAK UPSLOPE AND SOME EMBEDDED CONVECTION ALOFT. LOW TEMPS SHOULD BE MUCH MILDER THAN SEEN IN A WHILE WITH UPPER 30S TO MID 40S...WITH PERHAPS A FEW VALLEYS AND EASTERN SPOTS A BIT COLDER EARLY ON BEFORE RISING LATE AS CLOUDS/SHRA ARRIVE. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... AS OF 315 AM EDT SATURDAY... A WARM FRONT WILL SPREAD A QUICK SHOT OF RAIN ACROSS THE REGION DURING THE FIRST HALF OF SUNDAY. THE COLD FRONT HOLDS TO THE NW LONG ENOUGH SO THAT MONDAY WILL FEATURE MANY HIGHS IN THE 60S WITH H85 TEMPS FROM +4C TO +8C. ALTHOUGH ITS BEEN SAID WAY TOO MANY TIMES THIS MARCH...THE COLD SHOT ARRIVING MONDAY NIGHT THROUGH TUESDAY MAY BE WINTER`S LAST GASP...WITH -10C AT H85 ONCE AGAIN TOUCHING SE WEST VA. ALTHOUGH THE OP GFS IS GENERATING LIGHT SNOW ACROSS MOSTLY GREENBRIER MONDAY NIGHT...ALL OTHER MODELS SAY NO...AND ARE MUCH DRIER AT H85 AND H7. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 115 PM EDT FRIDAY... COLDER AIR PUSHING IN WITH STRONG CANADIAN HIGH MOVING SE INTO THE PLAINS. THIS HIGH MOVES INTO THE OHIO VALLEY BY WEDNESDAY AND SHIFTS EAST OF US THURSDAY. TEMPS WILL AGAIN BE FALLING WELL BELOW NORMAL WITH HIGHS TUE-WED IN THE UPPER 30S TO MID 40S MTNS...AND MID 40S TO LOWER 50S EAST. FOR THE THU NIGHT-FRI TIME FRAME...THE 00Z ECMWF SHOWS THE NEXT SHORTWAVE PUSHING INTO THE OHIO VALLEY SOUTH TO THE GULF COAST. MEANWHILE...THE 12Z GFS IS FASTER AND FURTHER SOUTH WITH ITS SYSTEM KEEPING PRECIP MORE OVER THE SOUTHEAST. THE ECMWF WORKS A WARM FRONT AND LOW NE TO THE AREA FRIDAY WITH RAIN...AND RETREATING HIGH PRESSURE. LEANED THE FORECAST TOWARD A WETTER SOLUTION SIMILAR TO THE ECMWF. SHOULD BE MAINLY RAIN BUT CANNOT RULE OUT SOME WINTRY PRECIP IF THE COLD AIR IS SLOW TO DISLODGE. BOTH MODELS AFTER FRIDAY CLOSE OFF AN UPPER LOW ALONG THE EAST COAST...DELMARVA AREA FOR ECMWF AND EAST OF SOUTH CAROLINA FOR THE GFS. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AS OF 650 AM EDT SATURDAY... AN UPPER LEVEL DISTURBANCE WILL CONTINUE TO TRACK SE OF THE AREA THIS MORNING ALLOWING A REDUCTION IN COVERAGE OF LOW/MID CLOUDS THROUGH MIDDAY. APPEARS ANY LEFTOVER MID DECK OR STRATO-CU LAYER ALONG WITH PATCHY FOG WILL QUICKLY MIX OUT THIS MORNING PER HEATING TO MORE SCTD/BKN VFR LEVEL CU BY AFTERNOON. THUS EXPECT GOOD FLYING CONDITIONS TO PREVAIL IN MOST AREAS INTO/THROUGH EARLY THIS EVENING BEFORE THE APPROACH OF A WARM FRONT BRINGS AN INCREASING THREAT OF SHOWERS ALONG WITH FLIGHT RESTRICTIONS BACK INTO MVFR OR IFR RANGE LATER TONIGHT INTO MUCH OF SUNDAY. LOOKS LIKE MOST OF THE RAINFALL WILL AFFECT THE WESTERN TAF LOCATIONS SUCH AS KBLF/KBCB SHORTLY AFTER MIDNIGHT...AND THEN PROGRESS NORTH/EAST OVER THE REMAINDER OF THE FORECAST POINTS BY DAYBREAK. COULD SEE CIGS/VSBYS RAPIDLY LOWER AS WELL AROUND DAWN ON SUNDAY AS A PERIOD OF MODERATE TO HEAVY RAIN TRACKS ACROSS PARTS OF THE AREA AS WELL. PASSAGE OF THE WARM FRONT EARLY AND SUBSEQUENT COLD FRONT LATER IN THE DAY SHOULD BRING END TO RAIN THREAT ALONG WITH CLEARING SKIES IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE BY LATE SUNDAY AFTERNOON. HOWEVER TYPICAL UPSLOPING CLOUDS..AND POSSIBLY SOME ISOLATED SHOWERS SHOULD MAINTAIN A THREAT FOR AT LEAST OCCASIONAL MVFR CEILINGS THROUGH SUNDAY NIGHT ACROSS SOUTHEASTERN WV TERMINAL FORECAST POINTS. APPROACH OF MUCH MORE POTENT COLD FRONT WILL MAINTAIN MVFR TO POSSIBLY IFR RESTRICTIONS WITH INCREASING THREAT OF PRECIPITATION ACROSS UPSLOPE AREAS OF THE WEST LATER MONDAY INTO MONDAY NIGHT. EXPECT VFR CONDITIONS EAST OF THE BLUE RIDGE TO BE OVERTAKEN BY AT LEAST MVFR RESTRICTIONS MONDAY NIGHT INTO TUESDAY MORNING AS COLD FRONT AND ASSOCIATED PRECIPITATION MOVE EAST THROUGH THE AREA. PROLONGED PERIOD OF COLD UPSLOPING WINDS AND SNOW SHOWERS WILL AGAIN MAINTAIN MVFR TO OCCASIONAL IFR RESTRICTIONS TO WESTERN FLANKS OF THE APPALACHIANS TUESDAY THROUGH WEDNESDAY...BUT WITH A RETURN TO VFR WEATHER EXPECTED IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE FOLLOWING FRONTAL PASSAGE TUESDAY AFTERNOON CONTINUING INTO WEDNESDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WP NEAR TERM...JH/KK SHORT TERM...KM LONG TERM...WP AVIATION...JH/WERT
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
126 AM EDT MON APR 1 2013 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PREVAIL OVERNIGHT. A COLD FRONT WILL MOVE ACROSS THE AREA LATE MONDAY AFTERNOON INTO MONDAY EVENING...FOLLOWED BY HIGH PRESSURE BUILDING FROM THE NORTH THROUGH THE MIDDLE OF THE WEEK. A LOW PRESSURE SYSTEM WILL THEN PASS ALONG THE SOUTHEAST COAST LATE IN THE WEEK INTO EARLY NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... UPSTREAM PCPN TRENDS AND LATEST RAP MODEL DATA HAVE TRENDED A BIT SLOWER WITH RAIN REACHING THE I-95 CORRIDOR THROUGH 6 AM. WE KNOCKED BACK POPS ALONG AND E OF I-95 DOWN ON THE MIDNIGHT UPDATE. TEMPS WILL BE NO LOWER THAN THE UPPER 50S AND LOWER 60S...MAKING THEM THE WARMEST NIGHT TIME LOWS IN MANY LOCALES SINCE FEBRUARY 11TH. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... MONDAY...A COLD FRONT WILL BE SITUATED ACROSS THE SOUTH CAROLINA MIDLANDS AND EAST-CENTRAL GEORGIA TO START THE DAY...WITH AN AXIS OF DEEP MOISTURE IN PLACE OVER THE AREA AHEAD OF THE FRONT WHERE PRECIPITABLE WATER VALUES WILL PEAK AROUND 1.3 TO 1.4 INCHES. THE DEEP MOISTURE COMBINED WITH FORCING FROM THE RIGHT ENTRANCE REGION OF A WEAKENING H25 JET WILL SUPPORT NUMEROUS SHOWERS ACROSS THE AREA IN THE MORNING. THE SHOWERS WILL THEN BEGIN TO TAPER OFF FROM THE WEST DURING THE AFTERNOON AS THE FRONT SHIFTS ACROSS THE AREA AND OFFSHORE BY LATE IN THE DAY. SOME THUNDERSTORMS ARE POSSIBLE...A FEW OF WHICH COULD BE STRONG/SEVERE AT TIMES WITH SURFACE BASED CAPE VALUES OF 800-1000 J/KG AND...LI VALUES OF -3C TO -5C AND MID LEVEL LAPSE RATES OF 6-7 C/KM. WET BULB ZERO HEIGHTS POSSIBLY REACHING AS LOW AS 8-9K FT WILL SUPPORT A HAIL THREAT...WITH DAMAGING WINDS ALSO POSSIBLE. THE GREATEST POTENTIAL FOR ANY STRONG/SEVERE THUNDERSTORMS APPEARS TO BE ACROSS SOUTHEAST GEORGIA...BUT GIVEN UNCERTAINTY IN THE EXTENT OF DIURNAL HEATING THAT CAN TAKE PLACE DUE TO EXTENSIVE CLOUD COVER AND PRECIPITATION...WILL KEEP MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR NOW. DESPITE THE EXTENSIVE CLOUD COVER INITIALLY...A GOOD SOUTHWEST FLOW AND WEAK COMPRESSIONAL HEATING AHEAD OF THE FRONT FOLLOWED BY A WARM WESTERLY FLOW IN ITS WAKE SHOULD ALLOW TEMPERATURES TO REACH HIGHS IN THE MID 70S ACROSS THE AREA AWAY FROM THE COOLER IMMEDIATE COAST. MONDAY NIGHT...A SECONDARY COLD FRONT WILL SWING THROUGH THE AREA DURING THE EVENING...WITH A DEVELOPING NORTHWEST/NORTH FLOW ADVECTING A DRIER AIRMASS INTO THE REGION. ANY LINGERING ISOLATED SHOWERS EARLY IN THE EVENING WILL QUICKLY COME TO AN END...WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED THROUGH THE REMAINDER OF THE NIGHT. LOW TEMPERATURES WILL BE IN THE UPPER 40S TO LOWER 50S. TUESDAY AND TUESDAY NIGHT...A WEAK BUBBLE HIGH WILL SETTLE OVER THE CAROLINAS WITH A NEARLY ZONAL FLOW IN PLACE ALOFT. RAIN-FREE CONDITIONS AND PARTLY CLOUDY SKIES ARE EXPECTED. A WEAK DOWNSLOPE FLOW ALOFT SHOULD HELP TEMPERATURES REACHES HIGH ON TUESDAY IN THE LOWER TO MID 70S ACROSS MUCH OF THE AREA AWAY FROM THE IMMEDIATE COAST...WITH SOME UPPER 70S EVEN POSSIBLE SOUTH OF THE I-16 CORRIDOR. LOWS TUESDAY NIGHT WILL BE IN THE UPPER 40S TO LOWER 50S ONCE AGAIN. WEDNESDAY...IT APPEARS THAT A WEAK BACKDOOR COLD FRONT DROPS THROUGH THE AREA IN RESPONSE TO A STRONGER WEDGE OF HIGH PRESSURE BUILDING FROM THE NORTH. THERE IS SOME MODEL DISAGREEMENT WITH RESPECT TO THE EXTENT OF MOISTURE ACCOMPANYING THE BUILDING WEDGE...WITH THE NAM MUCH MORE AGGRESSIVE THAN THE OTHER MODELS. WHILE THE CONSENSUS IS FOR NOT MUCH IN THE WAY OF RAINFALL STILL FEEL THAN AN ISOLATED SHOWER CANNOT BE RULED OUT AND THE FORECAST INDICATES A SLIGHT CHANCE OF RAIN AS A RESULT. THE TEMPERATURE FORECAST IS ALSO TRICKY AND THERE WILL LIKELY BE A LARGE GRADIENT ACROSS THE AREA...BUT FEEL THE SAFEST BET IS TO FORECAST HIGHS RANGING FROM THE LOWER AND MID 60S IN SOUTHEAST SOUTH CAROLINA TO THE UPPER 60S AND LOWER 70S IN SOUTHEAST GEORGIA. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... WEDNESDAY NIGHT THROUGH FRIDAY...WE WILL SEE A TRANSITION TO A MUCH WETTER PATTERN AS A SFC LOW DEEPENS OVER THE NORTHERN GULF WHILE AN H5 SHORTWAVE DIGS OVER THE DEEP SOUTH. PRECIP CHANCES WILL INCREASE IN SOUTHEAST GEORGIA..THEN INTO SOUTHEAST SOUTH CAROLINA AS AN EASTWARD EXTENDING WARM FRONT DEVELOPS WEDNESDAY NIGHT AND BECOMES POSITIONED ALONG THE SOUTHEAST COAST THURSDAY. THE AMOUNT OF RAINFALL ASSOCIATED WITH THIS SYSTEM WILL BE HIGHLY DEPENDENT ON THE POSITION OF THE WARM FRONT AND THE TRACK OF THE SFC LOW FROM THE NORTHERN GULF OF MEXICO TO THE SOUTHEAST COAST. AT THIS TIME...HIGH PRESSURE LOOKS TO MAINTAIN SOME HOLD OVER THE FORECAST AREA...THUS FORCING A MORE SOUTHERN TRACK OF THE SFC LOW OVER NORTHERN FLORIDA AND THEN ALONG THE SOUTHEAST COAST. WITH THIS TRACK IN MIND...HAVE INTRODUCED LIKELY POPS OVER SOUTHEAST GEORGIA AND CHANCE POPS OVER SOUTHEAST SOUTH CAROLINA WEDNESDAY NIGHT...WITH LIKELY POPS ACROSS THE AREA THURSDAY AND THURSDAY NIGHT BEFORE THE SFC LOW RAPIDLY DEEPENS AND SHIFTS TO THE NORTHEAST FRIDAY. SHOULD A MORE NORTHERN TRACK TAKE PLACE...A CHANCE OF THUNDERSTORMS WILL LIKELY NEED TO BE INTRODUCED OVER THE AREA. OVERALL TEMPS SHOULD REMAIN COOL ON THURSDAY WITH HIGH PRESSURE MAINTAINING A HOLD. OVERALL TEMPS SHOULD RANGE BETWEEN THE UPPER 50S NORTH...TO LOW/MID 60S SOUTH. BY FRIDAY...TEMPS SHOULD MODIFY A FEW DEGREES WITH THE WARM FRONT ALONG THE COAST. OVERNIGHT LOWS SHOULD REACH THE LOW/MID 40S WEDNESDAY NIGHT AND UPPER 40S TO LOWER 50S THURSDAY AND FRIDAY NIGHT. SATURDAY AND SUNDAY...A DRY AND WARMING TREND IS ANTICIPATED FOR THE SECOND HALF OF THE WEEKEND AS MID LVL RIDGING GRADUALLY EXPANDS INTO THE SOUTHEAST. WITH LITTLE CLOUD ANTICIPATED...OVERALL TEMPS SHOULD REACH THE UPPER 60S TO LOWER 70S SATURDAY AND LOWER 70S OVER MOST LOCATIONS ON SUNDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... OVERNIGHT WE HAVE MAINTAINED VFR WITH DRY WEATHER AT KSAV AND KCHS. LATEST MODEL GUIDANCE SUGGESTS THE BEST TIMING FOR SCATTERED SHOWERS WILL BE FROM 8 AM TO ABOUT NOON TODAY. TSTMS ARE POSSIBLE BUT TOO EARLY/UNCERTAIN TO INTRO TSRA/CB AT THIS TIME. THIS AFTERNOON...WEST WINDS WILL DIMINISH RAIN CHANCES AND MVFR CIG POTENTIAL BUT WILL HAVE TO WATCH FOR ISOLATED TSTMS AHEAD OF THE COLD FRONT. AFTER SUNSET...VFR CONDITIONS TO ALSO PREVAIL. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS SHOULD PREVAIL THROUGH WEDNESDAY. MVFR OR LOWER CIGS/VSBYS ARE POSSIBLE WEDNESDAY NIGHT THROUGH FRIDAY MORNING DUE TO RAIN/SHOWERS ASSOCIATED WITH A SFC LOW TRACKING OVER NORTHERN FLORIDA AND THEN ALONG THE SOUTHEAST COAST. && .MARINE... OVERNIGHT...THE COASTAL WATERS WILL BE SITUATED UNDER THE NW FRINGES OF ATLANTIC RIDGING...WITH AN UPSTREAM COLD FRONT OVER THE SE UNITED STATES. THE PRESSURE GRADIENT BETWEEN THESE TWO SYNOPTIC FEATURES WILL BE TIGHT ENOUGH WHERE SOUTH AND SW WINDS WILL REMAIN ELEVATED. SPEEDS WILL BE A SOLID 15 OR 20 KT OVER THE OCEAN...WITH FREQUENT GUSTS OF 25 KT ACROSS THE OUTER GA WATERS. IT IS THERE WHERE WE HAVE MAINTAINED THE SCA. IN CHARLESTON HARBOR WINDS WILL GENERALLY HOLD UNDER 15 KT. DUE TO THESE WINDS AND A SOMEWHAT FAVORABLE FETCH...SEAS WILL BE AS HIGH AS 3-5 FT WITHIN 20 NM OF THE SHORE...BUT 4-6 FT ACROSS THE GA WATERS 20-60 NM OUT. MONDAY THROUGH FRIDAY...SOUTHWEST FLOW WILL PREVAIL AHEAD OF AN APPROACHING COLD FRONT MONDAY...WITH A TIGHT SURFACE PRESSURE GRADIENT SUPPORTING MARGINAL SMALL CRAFT ADVISORY CONDITIONS OVER PORTIONS OF THE OUTER GEORGIA WATERS DURING THE MORNING. CONDITIONS WILL IMPROVE FOLLOWING THE PASSAGE OF A COLD FRONT MONDAY EVENING AS WINDS SHIFT OFFSHORE. BUILDING HIGH PRESSURE WILL ALLOW A NORTHEAST SURGE TO DEVELOP LATE MONDAY NIGHT INTO TUESDAY...WITH WINDS PEAKING AROUND 15-20 KT. WEAK HIGH PRESSURE OVER THE CAROLINAS WILL THEN KEEP CONDITIONS RATHER BENIGN OVER THE WATERS THROUGH TUESDAY NIGHT. A WEAK BACK DOOR COLD FRONT WILL DROP THROUGH AS STRONGER HIGH PRESSURE BUILDS FROM THE NORTH ON WEDNESDAY...CAUSING WINDS/SEAS TO BEGIN DETERIORATING LATE WEDNESDAY AND WEDNESDAY NIGHT. SMALL CRAFT ADVISORY CONDITIONS ARE THEN LIKELY LATE WEEK AS CONDITIONS DETERIORATE FURTHER DUE TO AN ENHANCED PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE WESTERN ATLANTIC AND LOW PRESSURE OVER THE NORTHERN GULF ON THURSDAY FOLLOWED BY THE PASSAGE OF A COASTAL LOW ALONG THE SOUTHEAST COAST THURSDAY NIGHT INTO FRIDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR AMZ374. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...JAQ LONG TERM...DPB/JAQ AVIATION... MARINE...
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
415 AM EDT MON APR 1 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 353 AM EDT MON APR 1 2013 A WEAK UPPER WAVE WILL MOVE THROUGH THE AREA THIS MORNING BUT HIGH PRESSURE WILL BUILD IN THIS AFTERNOON AND KEEP DRY WEATHER ACROSS THE AREA THROUGH SATURDAY. SATURDAY NIGHT A LOW PRESSURE SYSTEM WILL APPROACH AND BRING CHANCES FOR RAIN. TEMPERATURES WILL BE WELL BELOW NORMAL TODAY THROUGH TUESDAY NIGHT AND THEN REBOUND TO ABOVE NORMAL BY THE WEEKEND. && .NEAR TERM /TODAY/... ISSUED AT 353 AM EDT MON APR 1 2013 FORECAST FOCUS IS ON NEED FOR ANY POPS FROM EARLY TO MID MORNING. UPPER WAVE IS CURRENTLY MOVING SOUTHEAST THROUGH SOUTHERN IOWA AND WESTERN ILLINOIS. RADAR MOSAIC SHOWS WEAK ECHOES OVER WESTERN AND CENTRAL ILLINOIS AS WELL AS SOME ENTERING WESTERN INDIANA BUT SURFACE OBS SHOW NO PRECIP AT THE GROUND. GFS AND NAM ARE BOTH DRY AND GUIDANCE IS AS WELL. RAPID REFRESH AND RAP SHOW SOME DEVELOPMENT OCCURRING ACROSS THE SOUTHERN COUNTIES AROUND 11-12Z AND MOVING THROUGH BY 15Z. WITH BOTH OF THE RAPID UPDATE MODELS SHOWING THIS DEVELOPMENT WILL GO AHEAD AND LEAVE A SLIGHT CHANCE FOR RAIN AND SNOW MOVING ACROSS THE SOUTH FROM 11 TO 15Z AND DRY FROM 15Z ON. SHOULD NOT AMOUNT TO ANYTHING. WILL DROP ANY MENTION OF FLURRIES ELSEWHERE. CLOUDS SHOULD SCATTER OUT AS THE DAY GOES ON. WILL SEE COLD ADVECTION THROUGHOUT THE DAY SO TEMPERATURES SHOULD STRUGGLE TO WARM AND THUS WENT WITH A CONSENSUS OF RAW MODEL NUMBERS SINCE CLIMATOLOGY COULD BIAS THINGS UP. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 353 AM EDT MON APR 1 2013 HIGH PRESSURE WILL DOMINATE THE WEATHER IN THE SHORT TERM. MODELS ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS. WITH MOSTLY CLEAR TO CLEAR SKIES THROUGHOUT THE SHORT TERM STUCK CLOSE TO COOLER GUIDANCE NUMBERS AT NIGHT OF LOW TO MIDDLE 20S. FOR HIGHS TUESDAY AGAIN THOUGHT GUIDANCE WAS BIASED A BIT WARM FROM CLIMATOLOGY SO STUCK WITH A RAW MODEL CONSENSUS IN THE LOW TO MID 40S...BUT BY WEDNESDAY THE AIR MASS SHOULD BE REBOUNDING UNDER WARM ADVECTION AND A COMPLETE CONSENSUS LOOKED GOOD IN THE UPPER 40S TO LOW 50S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 324 AM EDT MON APR 1 2013 A LARGE AREA OF HIGH PRESSURE WILL BE MOVING AWAY TO THE EAST ON THURSDAY WITH A SPLIT FLOW PATTERN ALOFT AS A WEAK FRONT APPROACHES FROM THE NORTHWEST AND AN UPPER LOW TRACKS ACROSS THE SOUTHERN PLAINS. MODEL CONSENSUS HAS BEEN TRACKING THE UPPER WAVE FURTHER NORTH OVER THE LAST COUPLE DAYS AND BRINGS THE NORTHERN FRINGES OF THE RAINFALL ASSOCIATED WITH THE UPPER LOW INTO THE OHIO RIVER VALLEY THURSDAY NIGHT. CONSIDERING THE NORTHERLY LOW LEVEL FLOW...PRESENCE OF DRIER AIR OVER THE REGION AND THE BULK OF THE DEEPER FORCING REMAINING TO THE SOUTH OF THE FORECAST AREA...WILL CONTINUE TO KEEP A DRY FORECAST GOING THURSDAY NIGHT. DO ANTICIPATE AN INCREASE IN CLOUDS OVER THE SOUTHERN COUNTIES THURSDAY NIGHT AND EARLY FRIDAY AS THE UPPER WAVE PASSES TO THE SOUTH. THE AFOREMENTIONED WEAK FRONT APPROACHING FROM THE NORTHWEST SET TO WASH OUT ACROSS THE LOWER GREAT LAKES THURSDAY NIGHT. AS THE UPPER WAVE WEAKENS AND SHIFTS INTO THE SOUTHEAST STATES BY FRIDAY AFTERNOON...HIGH PRESSURE WILL REESTABLISH ACROSS THE OHIO VALLEY WITH AN EXPANSION OF RIDGING ALOFT BRINGING WARMER AIR INTO THE REGION. LOW LEVEL THERMALS SUPPORT HIGH TEMPS RISING INTO THE 60S BY SATURDAY. FORECAST MORE MUDDLED FOR THE SECOND HALF OF THE WEEKEND AS A DEVELOPING WARM FRONT SETS UP OVER THE LOWER GREAT LAKES AND A SURFACE WAVE TRACKS ALONG THE BOUNDARY ON SUNDAY. WILL CARRY LOW CHANCE POPS SATURDAY NIGHT INTO SUNDAY AS THE SURFACE WAVE PASSES THROUGH THE AREA. APPEARS THE BOUNDARY MAY SETTLE FURTHER SOUTH NEAR THE OHIO RIVER BY LATE SUNDAY WITH THE PASSAGE OF THE LOW...BEFORE THE BOUNDARY RETURNS BACK NORTH EARLY NEXT WEEK. LOW LEVEL THERMALS STILL SUGGESTIVE OF HIGHS IN THE 60S FOR SUNDAY EVEN AS THE BOUNDARY SHIFTS SOUTH...WITH POSSIBILITY FOR WARMER DAYTIME HIGHS EARLY NEXT WEEK ONCE THE FRONT LIFTS BACK NORTH. && .AVIATION /DISCUSSION FOR THE 010900Z TAF UPDATE/... ISSUED AT 415 AM EDT MON APR 1 2013 MID LEVEL CLOUDS EXPANDING BACK ACROSS THE TERMINALS EARLY THIS MORNING AS THE UPPER TROUGH SHARPENS OVER THE REGION. TWEAKED CLOUDS AND WIND SPEEDS BASED ON CURRENT OBS WITH EXPECTATION OF SOME GUSTS APPROACHING 20KTS THROUGH THE MORNING. AREA OF SCATTERED LIGHT SNOW SHOWERS/FLURRIES OVER NORTHEAST MISSOURI AND WESTERN ILLINOIS WILL MOVE EAST TOWARDS THE REGION BY DAYBREAK. AT THIS POINT HOWEVER... STILL APPEARS THIS AREA OF PRECIP WILL CONTINUE TO WEAKEN WITH POSSIBILITY OF JUST A FEW FLURRIES AT KBMG/KHUF/KIND IN THE 12-15Z PERIOD. WILL MAINTAIN NO PRECIP MENTION IN TERMINALS AT THIS TIME. 06Z DISCUSSION FOLLOWS. VFR THROUGH THE PERIOD. SCT TO BKN MID CLOUD LIKELY THE ONLY SKY COVER THROUGH THE NIGHT. WINDS WILL ONCE AGAIN GUST TOMORROW TO NEAR 20KT...AND DIURNAL CUMULUS WILL FORM AROUND 5KFT. NO VISIBILITY ISSUES ANTICIPATED THROUGH THE PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....RYAN AVIATION...NIELD/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
400 AM EDT MON APR 1 2013 .UPDATE... THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 353 AM EDT MON APR 1 2013 A WEAK UPPER WAVE WILL MOVE THROUGH THE AREA THIS MORNING BUT HIGH PRESSURE WILL BUILD IN THIS AFTERNOON AND KEEP DRY WEATHER ACROSS THE AREA THROUGH SATURDAY. SATURDAY NIGHT A LOW PRESSURE SYSTEM WILL APPROACH AND BRING CHANCES FOR RAIN. TEMPERATURES WILL BE WELL BELOW NORMAL TODAY THROUGH TUESDAY NIGHT AND THEN REBOUND TO ABOVE NORMAL BY THE WEEKEND. && .NEAR TERM /TODAY/... ISSUED AT 353 AM EDT MON APR 1 2013 FORECAST FOCUS IS ON NEED FOR ANY POPS FROM EARLY TO MID MORNING. UPPER WAVE IS CURRENTLY MOVING SOUTHEAST THROUGH SOUTHERN IOWA AND WESTERN ILLINOIS. RADAR MOSAIC SHOWS WEAK ECHOES OVER WESTERN AND CENTRAL ILLINOIS AS WELL AS SOME ENTERING WESTERN INDIANA BUT SURFACE OBS SHOW NO PRECIP AT THE GROUND. GFS AND NAM ARE BOTH DRY AND GUIDANCE IS AS WELL. RAPID REFRESH AND RAP SHOW SOME DEVELOPMENT OCCURRING ACROSS THE SOUTHERN COUNTIES AROUND 11-12Z AND MOVING THROUGH BY 15Z. WITH BOTH OF THE RAPID UPDATE MODELS SHOWING THIS DEVELOPMENT WILL GO AHEAD AND LEAVE A SLIGHT CHANCE FOR RAIN AND SNOW MOVING ACROSS THE SOUTH FROM 11 TO 15Z AND DRY FROM 15Z ON. SHOULD NOT AMOUNT TO ANYTHING. WILL DROP ANY MENTION OF FLURRIES ELSEWHERE. CLOUDS SHOULD SCATTER OUT AS THE DAY GOES ON. WILL SEE COLD ADVECTION THROUGHOUT THE DAY SO TEMPERATURES SHOULD STRUGGLE TO WARM AND THUS WENT WITH A CONSENSUS OF RAW MODEL NUMBERS SINCE CLIMATOLOGY COULD BIAS THINGS UP. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 353 AM EDT MON APR 1 2013 HIGH PRESSURE WILL DOMINATE THE WEATHER IN THE SHORT TERM. MODELS ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS. WITH MOSTLY CLEAR TO CLEAR SKIES THROUGHOUT THE SHORT TERM STUCK CLOSE TO COOLER GUIDANCE NUMBERS AT NIGHT OF LOW TO MIDDLE 20S. FOR HIGHS TUESDAY AGAIN THOUGHT GUIDANCE WAS BIASED A BIT WARM FROM CLIMATOLOGY SO STUCK WITH A RAW MODEL CONSENSUS IN THE LOW TO MID 40S...BUT BY WEDNESDAY THE AIR MASS SHOULD BE REBOUNDING UNDER WARM ADVECTION AND A COMPLETE CONSENSUS LOOKED GOOD IN THE UPPER 40S TO LOW 50S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 324 AM EDT MON APR 1 2013 A LARGE AREA OF HIGH PRESSURE WILL BE MOVING AWAY TO THE EAST ON THURSDAY WITH A SPLIT FLOW PATTERN ALOFT AS A WEAK FRONT APPROACHES FROM THE NORTHWEST AND AN UPPER LOW TRACKS ACROSS THE SOUTHERN PLAINS. MODEL CONSENSUS HAS BEEN TRACKING THE UPPER WAVE FURTHER NORTH OVER THE LAST COUPLE DAYS AND BRINGS THE NORTHERN FRINGES OF THE RAINFALL ASSOCIATED WITH THE UPPER LOW INTO THE OHIO RIVER VALLEY THURSDAY NIGHT. CONSIDERING THE NORTHERLY LOW LEVEL FLOW...PRESENCE OF DRIER AIR OVER THE REGION AND THE BULK OF THE DEEPER FORCING REMAINING TO THE SOUTH OF THE FORECAST AREA...WILL CONTINUE TO KEEP A DRY FORECAST GOING THURSDAY NIGHT. DO ANTICIPATE AN INCREASE IN CLOUDS OVER THE SOUTHERN COUNTIES THURSDAY NIGHT AND EARLY FRIDAY AS THE UPPER WAVE PASSES TO THE SOUTH. THE AFOREMENTIONED WEAK FRONT APPROACHING FROM THE NORTHWEST SET TO WASH OUT ACROSS THE LOWER GREAT LAKES THURSDAY NIGHT. AS THE UPPER WAVE WEAKENS AND SHIFTS INTO THE SOUTHEAST STATES BY FRIDAY AFTERNOON...HIGH PRESSURE WILL REESTABLISH ACROSS THE OHIO VALLEY WITH AN EXPANSION OF RIDGING ALOFT BRINGING WARMER AIR INTO THE REGION. LOW LEVEL THERMALS SUPPORT HIGH TEMPS RISING INTO THE 60S BY SATURDAY. FORECAST MORE MUDDLED FOR THE SECOND HALF OF THE WEEKEND AS A DEVELOPING WARM FRONT SETS UP OVER THE LOWER GREAT LAKES AND A SURFACE WAVE TRACKS ALONG THE BOUNDARY ON SUNDAY. WILL CARRY LOW CHANCE POPS SATURDAY NIGHT INTO SUNDAY AS THE SURFACE WAVE PASSES THROUGH THE AREA. APPEARS THE BOUNDARY MAY SETTLE FURTHER SOUTH NEAR THE OHIO RIVER BY LATE SUNDAY WITH THE PASSAGE OF THE LOW...BEFORE THE BOUNDARY RETURNS BACK NORTH EARLY NEXT WEEK. LOW LEVEL THERMALS STILL SUGGESTIVE OF HIGHS IN THE 60S FOR SUNDAY EVEN AS THE BOUNDARY SHIFTS SOUTH...WITH POSSIBILITY FOR WARMER DAYTIME HIGHS EARLY NEXT WEEK ONCE THE FRONT LIFTS BACK NORTH. && .AVIATION /DISCUSSION FOR THE 01/06Z TAFS/... ISSUED AT 104 AM EDT MON APR 1 2013 VFR THROUGH THE PERIOD. SCT TO BKN MID CLOUD LIKELY THE ONLY SKY COVER THROUGH THE NIGHT. WINDS WILL ONCE AGAIN GUST TOMORROW TO NEAR 20KT...AND DIURNAL CUMULUS WILL FORM AROUND 5KFT. NO VISIBILITY ISSUES ANTICIPATED THROUGH THE PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....RYAN AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS WICHITA KS
335 AM CDT MON APR 1 2013 .SYNOPSIS... ISSUED AT 332 AM CDT MON APR 1 2013 A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE FIRST PART OF THE WEEK. && .SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT) ISSUED AT 332 AM CDT MON APR 1 2013 THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE. THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN. BILLINGS .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 332 AM CDT MON APR 1 2013 BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST. SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S. TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY. ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS THE TIME PERIOD NEARS. BILLINGS && .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU ISSUED AT 1208 AM CDT MON APR 1 2013 AT 05Z A STRONG ALMOST E-W ORIENTED COLD FRONT THAT HAS BEEN MOVING S THIS EVENING ENTERED NRN KS ~03Z & SHOULD STILL ARRIVE KRSL & KSLN 08Z. THE COLD FRONT SHOULD REACH SC & SE KS ~10Z. DURING FRONTAL PASSAGE WINDS THAT ARE VARIABLE <7KTS WILL QUICKLY & ABRUPTLY SHIFT TOWARD THE NE & INCREASE TO A SUSTAINED ~17KTS/20MPH WITH GUSTS ~25KTS. POST-COLD FRONTAL ~1,500FT STRATOCU WILL SPREAD OVER PRIMARILY KSLN ~11Z BUT ONLY LAST TIL ~15Z. NE WINDS WILL GRADUALLY DIMINISH IN A N-S MANNER AS HIGH PRESSURE SPREADS S/SE FROM THE DAKOTAS TO NEBRASKA. ES && .FIRE WEATHER... ISSUED AT 332 AM CDT MON APR 1 2013 VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST. LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW. WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND FIRE DANGER WILL BE VERY HIGH. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 51 35 43 35 / 40 60 50 30 HUTCHINSON 50 33 45 32 / 30 40 40 20 NEWTON 51 32 43 31 / 30 30 30 20 ELDORADO 51 33 44 33 / 30 40 40 20 WINFIELD-KWLD 53 36 42 36 / 40 70 70 40 RUSSELL 51 30 48 30 / 20 30 20 10 GREAT BEND 50 31 46 31 / 20 30 30 20 SALINA 52 31 50 33 / 20 20 10 10 MCPHERSON 51 32 46 32 / 30 30 20 10 COFFEYVILLE 55 37 44 36 / 40 60 70 40 CHANUTE 53 34 44 34 / 30 30 30 10 IOLA 52 33 45 33 / 30 20 20 10 PARSONS-KPPF 53 35 44 35 / 30 50 50 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
523 AM EDT MON APR 1 2013 .SYNOPSIS... ISSUED AT 422 AM EDT MON APR 1 2013 A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER MICHIGAN. && .UPDATE... ISSUED AT 519 AM EDT MON APR 1 2013 CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP BY LATE MORNING. NO OTHER CHANGES ATTM. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 422 AM EDT MON APR 1 2013 HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES AS WELL. OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING THE SHORT TERM PORTION OF THE FORECAST. THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING COMMUTE. WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE COASTS. TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS WELL. SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS AFTERNOON. WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY NEAR THE LAKESHORES AND OVER EASTERN UPPER. TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID 20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE DAY. HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE. AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS. TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2 INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO COMPELLING REASON TO DEVIATE SIGNIFICANTLY. CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR... GENERALLY IN THE UPPER TEENS TO AROUND 20. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 422 AM EDT MON APR 1 2013 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. THE MOISTURE IN THE 850-700 MB LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON, THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE. THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON. TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW. WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY ALLOWING IT TO JUST TOUCH E UPPER BY 12Z. EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN. SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE PESSIMISTIC FORECAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 128 AM EDT MON APR 1 2013 SUMMARY: STRONG NORTHWEST FLOW WILL CONTINUE THROUGH THE UPCOMING TAF PERIOD...WITH LAKE EFFECT SNOW SHOWERS OCCASIONALLY IMPACTING THE TERMINALS. RESTRICTIONS: EXPECT VFR CONDITIONS TO DOMINATE MOST OF THE TAF PERIOD...WITH HEAVIEST LES OVERNIGHT TONIGHT REMAINING BETWEEN PLN AND TVC. BANDING LOOKS TO TARGET PLN SOMETIME LATER THIS MORNING/EARLY AFTERNOON...ALTHOUGH IT WILL LIKELY BE BREAKING UP INTO MORE CELLULAR ACTIVITY BY THIS TIME. SO...WILL ONLY INCLUDE A PERIOD OF MVFR WITH THIS TAF PACKAGE...AND AWAIT LATER TRENDS TO POTENTIALLY ADD A SHORT PERIOD OF IFR. AT THE OTHER TERMINALS...WHILE A QUICK DROP TO MVFR IN SHSN IS POSSIBLE...THERE IS LOW CONFIDENCE IN TIMING...SO WILL FOLLOW TRENDS THROUGH THE REMAINDER OF THE OVERNIGHT BEFORE ADDING ANY TEMPOS AT TVC/APN. AT THIS TIME...MBL LOOKS TO REMAIN VFR. WINDS: NORTHWEST WINDS 14G22KTS TONIGHT WILL CONTINUE 18G28KTS FOR THE DAY ON MONDAY BEFORE DIMINISHING TO 10-15KTS MONDAY NIGHT. && .MARINE... ISSUED AT 422 AM EDT MON APR 1 2013 SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY MIDWEEK WITH QUIETER CONDITIONS EXPECTED. HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS. BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF NEXT APPROACHING SYSTEM. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR MIZ019-021-022- 028. LH...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349. LM...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341-342- 344>346. LS...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321-322. && $$ UPDATE...ARNOTT SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...ARNOTT MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
444 AM EDT MON APR 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 440 AM EDT MON APR 1 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF CENTERED FM HUDSON BAY INTO THE GRT LKS DOWNSTREAM OF UPR RDG OVER WRN CANADA. 00Z H5/H85 TEMPS ARE AS LO AS -42C/-20C AT THE CORE OF THE COLDEST AIR AT YPL. CYC NNW FLOW ON THE WRN FLANK OF LO PRES MOVING SLOWLY E INTO QUEBEC IS DRAWING THIS VERY COLD AIR SWD INTO THE UPR LKS OVER THE RELATIVELY WARM WATERS OF LAKE SUP...WITH THE RESULT NMRS LES BANDS AS SHOWN ON MQT RADAR. WELL DEFINED AXIS OF COLDER CLD TOPS AS SHOWN ON IR STLT IMAGERY IS PRESENT OVER THE E HALF OF THE LK AND ASSOCIATED WITH FAIRLY SHARP H7-3 QVECTOR CNVGC. THIS AXIS OF DEEPER MSTR HAS CAUSED SOME ENHANCEMENT TO THE SHSN. THE HEAVIEST BAND IS STREAMING INTO CENTRAL ALGER COUNTY/SCHOOLCRAFT COUTY...WITH SOME RETURNS AOA 30 DBZ AT 06Z. SN UNDER THIS BAND IS LIKELY FALLING AT THE RATE OF AT LEAST AN INCH/HR GIVEN FAVORABLE LOCATION OF UVV MAX WITHIN DGZ AS SHOWN BY PROFILE FM LOCAL HI RES MODEL. SINCE THE COLDER CLD TOPS ARE TENDING TO DRIFT TO THE E AND DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB IS PRESSING TO THE E... DROPPING THE SFC DEWPT TO NEAR 7F AT IWD AT 06Z...THE INTENSITY OF THE LES W OF MQT HAS TENDED TO DIMINISH OVER TIME PER RADAR TRENDS EVEN THOUGH IR STLT IMAGERY INDICATES SOME LES BANDS OVER THE W HALF OF THE LK THAT HAVE FORMED IN THE PRESENCE OF NOCTURNAL COOLING THAT IS SO IMPORTANT TO ACHIEVE BETTER LES BAND STRUCTURE THIS TIME OF YEAR. NW WINDS ARE STILL GUSTING AS HI AS 40 KTS AT STANNARD ROCK AS OF 06Z...BUT PASSAGE OF PRES RISE CENTER TRAILING THE SFC LO INTO ONTARIO E OF LK SUP HAS CAUSED A SLOW DIMINISHING TREND TO THE WINDS. MAIN FCST CONCERNS THIS PACKAGE ARE LES TRENDS/GOIND HEADLINES. TODAY...MODELS INDICATE UPR TROF AXIS WL DRIFT SLOWLY TO THE E. AREA OF DEEP LYR QVECTOR CNVGC ENHANCING COMMA HEAD/COLDER CLD TOPS NOW OVER THE E HALF OF LK SUP IS PROGGED TO DRIFT INTO ONTARIO IN THE 09Z-12Z TIME FRAME. IN CONCERT WITH THE ARRIVAL OF SOME DRYING FM THE W...LES INTENSITY/COVERAGE SHUD DIMINISH BY SUNRISE. BUT GIVEN PERSISTENCE OF SGNFT BAND OVER CENTRAL ALGER COUNTY INTO NRN SCHOOLCRAFT COUNTY IN PERSISTENT NNW FLOW THRU THE EARLY MRNG HRS...FVRBL SN/WATER RATIOS UNDER COLDEST H85 TEMPS...AND HIER RES MODEL FCSTS THAT SHOWING FAIRLY HI QPF THRU 18Z WITH DEEPER MSTR PERSISTING LONGEST IN THAT AREA CLOSER TO DEPARTING LO...OPTED TO UPGRADE GOING ADVY FOR THOSE ZONES TO AN LES WARNING. OTRW...RISING H5 HGTS/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE PRESENCE OF DIURNAL HEATING THAT TENDS TO DISRUPT THE LES PROCESS IN EARLY SPRING SHOULD CAUSE THE LES BANDS TO WEAKEN AND TRANSITION TO A MORE BLOTCHY APPEARANCE. SLOWLY BACKING FLOW TOWARD MORE WNW BY THE LATE IN THE DAY WL ALSO CAUSE AREA OF HEAVIER SHSN TO SHIFT. ADDITIONAL SN AMOUNTS OVER THE W WL BE LIGHT WITH LLVL DRY AIR HAVING A MORE SGNFT IMPACT THERE AND MODELS HINTING TOWARD A TRANSITION TO LLVL ACYC FLOW IN THE AFTN. TONIGHT...STEADILY RISING HGTS/DEEP LYR QVECTOR CNVGC THAT DROPS FCST INVRN BASE TOWARD 5-6K FT OVER EVEN THE E SUG LES INTENSITY WL BE SOMEWHAT DIMINISHED EVEN THOUGH PERSISTENT NW FLOW/H85 TEMPS IN THE -16 TO -17C RANGE WL ALLOW FOR CONTINUED WDSPRD LES...ESPECIALLY AFTER MID EVNG WHEN IMPACTS OF DAYTIME HEATING WOULD TEND TO SUBSIDE. WITH INVRN BASE OVER THE W FALLING TO ARND 4K FT OVER THE W...SHSN INTENSITY IN THIS AREA WL BE WEAKER WITH SHORTER FETCH/LESS MODERATION OF UPSTREAM AIRMASS. BUT STILL WENT WITH LIKELY POPS GIVEN FVRBL NW FLOW/OVERWATER INSTABILITY/NOCTURNAL COOLING THAT WL ALLOW LES BANDS TO REDEVELOP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 440 AM EDT MON APR 1 2013 DESPITE ADEQUATE DELTA TS PERSISTING INTO TUESDAY FOR LAKE EFFECT...SFC-H85 FLOW WILL BECOME INCREASINGLY ANTICYCLONIC THROUGH THE DAY. IN ADDITION...INVERSION HEIGHTS BEGIN TO FALL OFF SIGNIFICANTLY BELOW 5KFT. THUS...EXPECT OVERALL COVERAGE AND INTENSITY OF LAKE EFFECT TO BE ON THE WANE AS THE DAY PROGRESSES. TEMPERATURES WILL REMAIN WELL BELOW NORMAL WITH A SIGNIFICANT AMOUNT OF CLOUDINESS DOWNWIND OF LAKE SUPERIOR. LAKE CLOUDS AND EVEN A FEW FLURRIES WILL PERSIST INTO THE MORNING WEDNESDAY OVER THE EAST. AS SURFACE RIDGE AXIS MOVES OVERHEAD THROUGH THE DAY EXPECT SKIES TO BECOME MOSTLY SUNNY AREA WIDE. TEMPERATURES SHOULD REBOUND BACK ABOVE FREEZING AND EVEN APPROACH 40 ACROSS THE WEST WITH WARM ADVECTION INCREASING DURING THE AFTERNOON AND MORE SUNSHINE. MODELS COMING INTO BETTER AGREEMENT WITH THE TIMING OF THE NEXT SHORTWAVE AND SFC TROUGH EXPECTED TO MOVE ACROSS THE AREA WED NIGHT/THU. THE TREND HAS BEEN TOWARD QUICKER MOVEMENT WITH THE TROUGH. SYSTEM IS FAIRLY MOISTURE STARVED...SO DESPITE PRECIP TYPE BEING A CHALLENGE BETWEEN RAIN AND SNOW...AMOUNTS WILL BE LIGHT ENOUGH TO BE PRETTY INSIGNIFICANT. COLD ADVECTION BEHIND THE TROUGH SHOULD PUSH 85H TEMPS BACK DOWN TO THE -10 TO -14C RANGE BY FRIDAY. PROBABLY NOT QUITE COLD ENOUGH FOR LAKE EFFECT THIS TIME AROUND...BUT COLDER AIR WILL KEEP DAYTIME TEMPS BELOW AVERAGE ONLY IN THE 30S. FORECAST FOR NEXT WEEKEND STILL PRETTY CHALLENGING...BUT MODELS SHOWING SOME SIGNS THAT THEY ARE TRYING TO CONVERGE ON A MORE PROBABLE OUTCOME. SHORTWAVE ENERGY AND ASSOCIATED SURFACE LOW MOVING OUT OF THE PLAINS LOOKING LIKE THEY MAY NOW TRACK THROUGH THE LOWER LAKES WHICH WOULD STILL RESULT IN SOME LIGHT SNOWFALL ACROSS SOUTHERN AREAS SATURDAY INTO SUNDAY BUT SPARE THE AREA FROM A MORE SIGNIFICANT STORM. IT IS STILL SOMETHING TO KEEP AN EYE ON AS WE HEAD THROUGH THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 129 AM EDT MON APR 1 2013 INCREASINGLY COLDER AIR MOVING ACROSS LAKE SUPERIOR IN NW FLOW WILL SUSTAIN PERIODS OF LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS INTO MONDAY AT ALL 3 TAF SITES. GUSTY NW WINDS TO 25 KTS AT TIMES COULD ALSO CONTRIBUTE TO LOWER IFR VSBYS IN SNOW AND BLOWING SNOW...MAINLY AT MORE EXPOSED KCMX SITE. WINDS BACKING A BIT MORE TO THE WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT KSAW BY MONDAY AFTERNOON...PERHAPS EVEN LEADING TO VFR CONDITIONS BY MONDAY EVENING. ARRIVAL OF DRIER NEAR SFC AIR SHOWN ON THE 00Z INL RAOB WILL ALSO BRING ABOUT LONG PERIODS OF VFR CONDITIONS AT IWD. THE COMBINATION OF THE DRYING AND DAYTIME HEATING THIS AFTN WILL DIMINISH THE LES INTENSITY AT CMX AS WELL. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 440 AM EDT MON APR 1 2013 AS LO PRES OVER SE CANADA CONTINUES TO THE E AND THE PRES GRADIENT WEAKENS...EXPECT NW WINDS TO SLOWLY DIMINISH AND BELOW GALE FORCE OVER THE CENTRAL BY MID MORNING...SO HASTENED THE ENDING OF THE GALE WARNINGS FOR THIS AREA. ALTHOUG NW GALES TO 35 KTS WILL CONTINUE LONGER OVER THE E INTO THIS EVENING...ENDED THE GALES FOR THAT AREA EARLIER AS WELL. WINDS/WAVES WILL BE SUFFICIENT TO MAINTAIN FREEZING SPRAY OVER AT LEAST THE E HALF THRU TONIGHT. WINDS WILL REMAIN PRETTY GUSTY UP TO 30 KNOTS OVER THE EASTERN LAKE THROUGH THE DAY ON TUESDAY...BUT AS SURFACE RIDGE AXIS PUSHES IN FROM THE WEST PRESSURE GRADIENT WILL RELAX AND WINDS WILL DIMINISH DURING THE EVENING. UNTIL THAT TIME...FREEZING SPRAY SHOULD CONTINUE ACROSS THE EASTERN LAKE. AFTER A BRIEF RESPITE ON WEDNESDAY...SOUTHWESTERLY WINDS UP TO 25 KNOTS AHEAD OF THE NEXT TROUGH CROSSING THE LAKE WILL INCREASE WEDNESDAY NIGHT INTO EARLY THURSDAY BEFORE SHIFTING TO THE NORTHWEST DURING THE DAY THURSDAY INTO THURSDAY NIGHT. WINDS FOR FRIDAY INTO NEXT WEEKEND SHOULD BE BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007. LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-085. LAKE SUPERIOR... GALE WARNING UNTIL 2 AM EDT TUESDAY FOR LSZ266-267. GALE WARNING UNTIL NOON EDT TODAY FOR LSZ265. GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ264. GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249. GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ244-245. GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...MZ AVIATION...VOSS/KC MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS GAYLORD MI
430 AM EDT MON APR 1 2013 .SYNOPSIS... ISSUED AT 422 AM EDT MON APR 1 2013 A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER MICHIGAN. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 422 AM EDT MON APR 1 2013 HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES AS WELL. OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING THE SHORT TERM PORTION OF THE FORECAST. THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING COMMUTE. WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE COASTS. TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS WELL. SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS AFTERNOON. WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY NEAR THE LAKESHORES AND OVER EASTERN UPPER. TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID 20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE DAY. HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE. AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS. TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2 INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO COMPELLING REASON TO DEVIATE SIGNIFICANTLY. CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR... GENERALLY IN THE UPPER TEENS TO AROUND 20. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 422 AM EDT MON APR 1 2013 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. THE MOISTURE IN THE 850-700 MB LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON, THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE. THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON. TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW. WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY ALLOWING IT TO JUST TOUCH E UPPER BY 12Z. EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN. SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE PESSIMISTIC FORECAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 128 AM EDT MON APR 1 2013 SUMMARY: STRONG NORTHWEST FLOW WILL CONTINUE THROUGH THE UPCOMING TAF PERIOD...WITH LAKE EFFECT SNOW SHOWERS OCCASIONALLY IMPACTING THE TERMINALS. RESTRICTIONS: EXPECT VFR CONDITIONS TO DOMINATE MOST OF THE TAF PERIOD...WITH HEAVIEST LES OVERNIGHT TONIGHT REMAINING BETWEEN PLN AND TVC. BANDING LOOKS TO TARGET PLN SOMETIME LATER THIS MORNING/EARLY AFTERNOON...ALTHOUGH IT WILL LIKELY BE BREAKING UP INTO MORE CELLULAR ACTIVITY BY THIS TIME. SO...WILL ONLY INCLUDE A PERIOD OF MVFR WITH THIS TAF PACKAGE...AND AWAIT LATER TRENDS TO POTENTIALLY ADD A SHORT PERIOD OF IFR. AT THE OTHER TERMINALS...WHILE A QUICK DROP TO MVFR IN SHSN IS POSSIBLE...THERE IS LOW CONFIDENCE IN TIMING...SO WILL FOLLOW TRENDS THROUGH THE REMAINDER OF THE OVERNIGHT BEFORE ADDING ANY TEMPOS AT TVC/APN. AT THIS TIME...MBL LOOKS TO REMAIN VFR. WINDS: NORTHWEST WINDS 14G22KTS TONIGHT WILL CONTINUE 18G28KTS FOR THE DAY ON MONDAY BEFORE DIMINISHING TO 10-15KTS MONDAY NIGHT. && .MARINE... ISSUED AT 422 AM EDT MON APR 1 2013 SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY MIDWEEK WITH QUIETER CONDITIONS EXPECTED. HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS. BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF NEXT APPROACHING SYSTEM. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349. LM...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341-342- 344>346. LS...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321-322. && $$ SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...ARNOTT MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
235 AM EDT MON APR 1 2013 .UPDATE... ISSUED AT 233 AM EDT MON APR 1 2013 OPTED TO UPGRADE ADVY FOR ALGER/NRN SCHOOLCRAFT TO A WARNING GIVEN PERSISTENCE OF INTENSE LES BAND JUST E OF MUNISING UNDER COLDER CLD TOPS ASSOCIATED WITH DEEPENING UPR TROF...FVRBL SN/WATER RATIOS WITH UVV MAX WITHIN DGZ...AND REPORTS OF SGNFT BLSN/WHITEOUT CONDITIONS ALONG M-28. ALTHOUGH THE EXPECTED DEPARTURE OF THE COLDER CLD TOPS BY 09Z WOULD SUG THE BAND WL DIMINISH...PERSISTENCE OF BAND SINCE MID EVNG ARND 03Z AND ESTIMATED SN ACCUMS UP TO 2 INCHES/HR SINCE BAND DVLPD SUG WARNING AMNTS ARE LIKELY FM SHINGLETON AND MELSTRAND TO GRAND MARAIS AND SENEY. && .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 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 129 AM EDT MON APR 1 2013 INCREASINGLY COLDER AIR MOVING ACROSS LAKE SUPERIOR IN NW FLOW WILL SUSTAIN PERIODS OF LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS INTO MONDAY AT ALL 3 TAF SITES. GUSTY NW WINDS TO 25 KTS AT TIMES COULD ALSO CONTRIBUTE TO LOWER IFR VSBYS IN SNOW AND BLOWING SNOW...MAINLY AT MORE EXPOSED KCMX SITE. WINDS BACKING A BIT MORE TO THE WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT KSAW BY MONDAY AFTERNOON...PERHAPS EVEN LEADING TO VFR CONDITIONS BY MONDAY EVENING. ARRIVAL OF DRIER NEAR SFC AIR SHOWN ON THE 00Z INL RAOB WILL ALSO BRING ABOUT LONG PERIODS OF VFR CONDITIONS AT IWD. THE COMBINATION OF THE DRYING AND DAYTIME HEATING THIS AFTN WILL DIMINISH THE LES INTENSITY AT CMX AS WELL. && .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... WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007. LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-085. LAKE SUPERIOR... GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251-266-267. GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ244-245-264-265. GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249. LAKE MICHIGAN... NONE. && $$ UPDATE...KC SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...VOSS/KC MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 AM EDT MON APR 1 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 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 129 AM EDT MON APR 1 2013 INCREASINGLY COLDER AIR MOVING ACROSS LAKE SUPERIOR IN NW FLOW WILL SUSTAIN PERIODS OF LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS INTO MONDAY AT ALL 3 TAF SITES. GUSTY NW WINDS TO 25 KTS AT TIMES COULD ALSO CONTRIBUTE TO LOWER IFR VSBYS IN SNOW AND BLOWING SNOW...MAINLY AT MORE EXPOSED KCMX SITE. WINDS BACKING A BIT MORE TO THE WNW...SHOULD REDUCE CHCS FOR LAKE EFFECT SNOW SHOWERS AT KSAW BY MONDAY AFTERNOON...PERHAPS EVEN LEADING TO VFR CONDITIONS BY MONDAY EVENING. ARRIVAL OF DRIER NEAR SFC AIR SHOWN ON THE 00Z INL RAOB WILL ALSO BRING ABOUT LONG PERIODS OF VFR CONDITIONS AT IWD. THE COMBINATION OF THE DRYING AND DAYTIME HEATING THIS AFTN WILL DIMINISH THE LES INTENSITY AT CMX AS WELL. && .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... WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006- 007-085. LAKE SUPERIOR... GALE WARNING UNTIL 6 AM EDT TUESDAY FOR LSZ250-251-266-267. GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ244-245-264-265. GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...VOSS/KC MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1145 PM EDT SUN MAR 31 2013 .AVIATION... //DISCUSSION... LOWER VFR STRATUS WILL CONTINUE TO FUNNEL ACROSS SOUTHEAST MICHIGAN OVERNIGHT IN THE WAKE OF A STRONG COLD FRONTAL PASSAGE. RECENT OBSERVATIONS DO INDICATE THAT A BRIEF MVFR CEILING MAY EMERGE...BUT CURRENT TRENDS SHOW TOO LIMITED OF COVERAGE AND DURATION TO WARRANT A MENTION AT THIS STAGE. SOLID NORTHWEST GRADIENT IN PLACE WITH 10-15 KNOT SPEEDS PERSISTING THROUGH THE NIGHT. THE DEGREE OF COLD AIR ADVECTION WILL PROVIDE SOME DEPTH TO THE MIXED LAYER...YIELDING THE OCCASIONAL 20 KNOT GUST THROUGH THE EARLY MORNING. CEILINGS GRADUALLY CLIMB MONDAY...SETTLING INTO THE 5-6K FT RANGE WITH DIURNAL HEATING BY THE AFTERNOON. GUSTY NORTHWEST WINDS FOR MONDAY AFTERNOON...PEAK GUST POTENTIAL IN THE 25-28 KNOT RANGE. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS AT LEAST INTERMITTENTLY FALLING BELOW 5000 FEET THROUGH THE MORNING HOURS MONDAY. && .PREV DISCUSSION...ISSUED 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. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...UNTIL 10 PM MONDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 8 AM TUESDAY. SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL 10 PM MONDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....MR SHORT TERM...DRK LONG TERM....SC MARINE.......DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS JACKSON MS
1025 PM CDT SUN MAR 31 2013 .UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE FORECAST AREA FOR TONIGHT. MANY AREAS OF DENSE FOG HAVE DEVELOPED AND WITH LIGHT WINDS AND NO CLOUD COVER EXPECTED TO DEVELOP FOG COVERAGE IS EXPECTED TO INCREASE OVERNIGHT. TEMPERATURES HAVE ALSO BEEN TWEAKED SLIGHTLY. && .PREV 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...AREAS OF IFR/MVFR CLOUD DECKS AND IFR/LIFR CONDITIONS IN FOG WILL CONTINUE THIS EVENING. FOG WILL BE ON THE INCREASE WITH WIDESPREAD IFR/LIFR CIGS/VSBYS DUE TO FOG. FOG WILL CLEAR AND LOW CLOUDS WILL LIFT BY 14Z MONDAY FOR VFR CONDITIONS BY LATE MORNING. && .JAN WATCHES/WARNINGS/ADVISORIES... MS...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR MSZ018-019-025>066- 072>074. LA...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR LAZ007>009-015-016- 023>026. AR...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR ARZ074-075. && $$ 03/ALLEN/15
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
241 AM MDT MON APR 1 2013 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT ISSUED AT 240 AM MDT MON APR 1 2013 ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME. THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S. RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR SOME PASSING CIRRUS. TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH. && .LONG TERM...WEDNESDAY THROUGH SUNDAY ISSUED AT 240 AM MDT MON APR 1 2013 UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE WEEKEND. && .AVIATION...FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT ISSUED AT 240 AM MDT MON APR 1 2013 MVFR AND LOCAL IFR CIGS WILL PERSIST ACROSS WESTERN SOUTH DAKOTA THROUGH THE MORNING HOURS BEFORE LIFTING AND SHIFTING EAST BY 18Z. VFR CONDITIONS ARE THEN EXPECTED THROUGH TUESDAY MORNING. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...JC LONG TERM...15 AVIATION...15
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
311 AM CDT MON APR 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 311 AM CDT MON APR 1 2013 A BROAD/DEEP MID TO UPPER LEVEL TROUGH HAS SET UP ACROSS SOUTHEASTERN CANADA WHILE AN AMPLIFYING RIDGE DEVELOPS ACROSS THE WESTERN US. AT THE SURFACE...CYCLONIC FLOW PERSISTS ACROSS THE GREAT LAKES AND UPPER MISSISSIPPI RIVER VALLEY AS A RIDGE OF HIGH PRESSURE PUSHES DOWN TO THE SOUTHEAST ACROSS THE DAKOTAS. SKIES HAVE MAINLY CLEARED OUT THOUGH A FEW CU STREAKS HAVE STUCK AROUND NORTHERN WISCONSIN. SHOULD NOT SEE MUCH IN THE WAY OF CHANGES IN THE PATTERN FOR TODAY AS THE RIDGE UNDERCUTS THE REGION TO THE SOUTHWEST AND STRONGLY SUBSIDENT AIR SHOULD KEEP SKIES MAINLY CLEAR. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 311 AM CDT MON APR 1 2013 WITH 850MB TEMPERATURES STAYING BETWEEN -10C TO -15C INTO WEDNESDAY MORNING...TEMPERATURES WILL STAY WELL BELOW NORMAL OVER THIS PERIOD. THE COLDEST MORNING WILL LIKELY BE ON WEDNESDAY MORNING AS THE CORE OF THE RIDGE MOVES OVERHEAD AND ALLOWS FOR IDEAL RADIATIONAL COOLING WITH CLEAR SKIES AND LIGHT WINDS. THINK THAT SOME OF THE MODELS ARE LEANING TOWARD CLIMO AND HAVE SOME HIGHER VALUES IN THERE...SO HAVE UNDERCUT LOWS THERE A BIT FOR WEDNESDAY MORNING. TEMPERATURES WILL BE ON THE INCREASE ON WEDNESDAY AS THE RIDGE AXIS MOVES IN FROM THE WEST AND 850MB TEMPERATURES IMPROVE TO AROUND -2C TO 0C. HIGH TEMPERATURES WILL STILL BE BELOW NORMAL BUT AT LEAST WILL BE TRENDING IN THE RIGHT DIRECTION. A MID LEVEL TROUGH WILL THEN TRACK ACROSS SOUTHERN CANADA WEDNESDAY NIGHT INTO THURSDAY AND IN TURN BRING A SURFACE LOW ALONG WITH IT. A COLD FRONT WILL EXTEND SOUTH OF THIS LOW AND WILL APPROACH CENTRAL MINNESOTA/NORTHERN WISCONSIN EARLY THURSDAY MORNING. THE BETTER LIFT/MOISTURE CONVERGENCE STILL APPEARS TO BE OFF TO THE NORTHEAST CLOSER TO THE MID LEVEL/SURFACE LOW...SO IT DOES NOT LOOK LIKE THERE SHOULD BE MUCH PRECIPITATION THAT OCCURS ALONG/AHEAD OF THE COLD FRONT. THERMAL PROFILES OFF OF THE 01.00Z GFS SUGGEST THAT THE PRECIPITATION SHOULD MAINLY FALL AS LIGHT RAIN...BUT CAN NOT RULE OUT THAT THERE COULD BE SOME SNOW THAT MIXES IN AS THE PROFILE SATURATES DOWN TO THE WET BULB TEMPERATURE. THE FOCUS THEN GOES TO A MORE POTENT SYSTEM THAT WILL BE DEVELOPING IN THE CENTRAL PLAINS ON FRIDAY WITH THE AFOREMENTIONED COLD FRONT TRANSITIONING TO A WARM FRONT. THE INITIAL QUESTION REMAINS WITH HOW FAR NORTH THAT FRONT MAKES IT NEXT WEEKEND AS TEMPERATURES WILL LIKELY BE IN THE 60S TO THE SOUTH OF IT AND IN THE 30S WITH SNOW TO THE NORTH OF IT. THE ECMWF HAS FLIP FLOPPED AROUND A BIT THE PAST FEW DAYS WITH THE TRACK OF THE SURFACE LOW THAT EVENTUALLY COMES THROUGH THE REGION ON SUNDAY WHILE THE GFS HAS BEEN FAIRLY STEADY WITH ITS TRACK. A FEW OF THE ECMWF RUNS HAVE TAKEN A MORE NORTHERLY TRACK THROUGH SOUTHERN MINNESOTA/CENTRAL WISCONSIN WHILE THE GFS HAS BEEN FAIRLY CONSISTENT WITH TAKING THE LOW THROUGH IOWA. PRECIPITATION WILL INITIALLY START OUT WELL AHEAD OF THIS LOW AS WARM AIR ADVECTION/FRONTOGENESIS STRENGTHENS ALONG THE THERMAL GRADIENT. A LOT OF DETAILS TO BE WORKED OUT AND HAVE BASICALLY DONE A BLEND BETWEEN THE 01.00Z GFS/ECMWF WITH THIS SYSTEM BUT SOME DRASTIC CHANGES COULD BE IN STORE DEPENDING ON WHETHER WE END UP IN THE WARM OR COLD SECTOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) 1148 PM CDT SUN MAR 31 2013 SURFACE HIGH PRESSURE WILL BUILD SOUTHEAST FROM THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY THROUGH THE TAF PERIOD. NORTHWEST WINDS WILL CONTINUE INTO THE 10 TO 15 KNOT RANGE THROUGH 00Z TUESDAY...THEN DIMINISH AS THE SURFACE HIGH SPREADS EASTWARD INTO THE AREA. SOME PATCHES OF MVFR CLOUDS SEEN ON SATELLITE ACROSS NORTHERN MINNESOTA. MODELS...ESPECIALLY THE NAM AND RAP ARE BOTH OVERDOING THE CURRENT MOISTURE FIELD. DID MENTION SCATTERED CLOUDS WITH BASES BETWEEN 020-030K FEET AFTER 11Z AT KRST AND 15Z AT KLSE. THIS WILL THEN DISSIPATE AFTER 00Z TUESDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CDT SUN MAR 31 2013 .SHORT TERM...TONIGHT THROUGH WEDNESDAY 321 PM CDT SUN MAR 31 2013 AT 3 PM...A CANADIAN COLD FRONT EXTENDED FROM TRAVERSE CITY MICHIGAN TO COLUMBIA MISSOURI. ANOTHER MUCH STRONGER CANADIAN COLD FRONT EXTENDED FROM IRONWOOD MICHIGAN TO MANKATO MINNESOTA. SCATTERED RAIN AND SNOW SHOWERS WERE DEVELOPING AHEAD OF THIS SECOND FRONT ACROSS WESTERN WISCONSIN. WITH 925-800 MB LAPSE RATES RUNNING AROUND 8C/KM... THE STRONGER WINDS FROM ALOFT ARE MIXING DOWN TO THE SURFACE. JUST IN THE PAST HOUR...THE WINDS HAVE BEEN GUSTING INTO THE 30 TO 35 MPH RANGE ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA. THE STRONGEST WIND GUST /36 MPH/ WAS A MAYO HELIPAD IN ROCHESTER MINNESOTA. THESE WIND GUST WILL QUICKLY WANE EARLY THIS EVENING WITH THE LOSS OF DIURNAL HEATING. FOR LATE TONIGHT AND MONDAY...THE 31.12Z NAM/WRF SHOWS THAT SOME OF THE CLOUDS ACROSS NORTHERN MINNESOTA...WESTERN ONTARIO...AND EASTERN MANITOBA WILL MOVE SOUTHEAST TOWARD THE FORECAST AREA. IN ADDITION WITH CONVECTIVE TEMPERATURE IN THE MID TO UPPER 20S...THIS WOULD ALSO FAVOR THE DEVELOPMENT OF A SCATTERED TO BROKEN DECK OF CUMULUS CLOUDS. IN ADDITION...THE 31.12Z NMM WOULD SUGGEST THE POSSIBILITY OF A FEW SNOW SHOWERS ACROSS TAYLOR COUNTY AND THE NORTHERN PORTIONS OF CLARK COUNTY IN CENTRAL AND NORTH CENTRAL WISCONSIN. SINCE THIS IS THE ONLY MODEL SHOWING THIS...KEPT THE FORECAST DRY FOR NOW. ON TUESDAY AFTERNOON...THE MODELS CONTINUE TO SHOW THAT ANOTHER SHORT WAVE TROUGH MOVE THROUGH THE NORTHERN AND EASTERN PORTIONS OF WISCONSIN. THE SOUNDINGS SHOW A SLIGHT SATURATION OCCURRING BETWEEN 850 AND 700 MB. WITH THE 270-280K ISENTROPIC CONDENSATION PRESSURE DEFICITS GREATER THAN 100 MB NOT EXPECTING VERY MANY CLOUDS OR PRECIPITATION FROM THIS SYSTEM. ON WEDNESDAY...THE MODELS CONTINUE TO SLOW THE EASTWARD PROGRESSION OF A FRONT MOVING TOWARD THE AREA FROM THE NORTHERN PLAINS. DUE TO THIS...THE PRESSURE GRADIENT IS NOT AS TIGHT AND THE AREA DOES NOT MIX AS DEEP. AS RESULT...COOLED THE HIGH TEMPERATURES A FEW DEGREES. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY 321 PM CDT SUN MAR 31 2013 ON THURSDAY...A FRONT WILL MOVE THROUGH THE AREA. IT CONTINUES TO LOOK LIKE THE BEST SYNOPTIC AND ISENTROPIC LIFT AND THE BEST 925 TO 850 MB MOISTURE TRANSPORT WILL BE MAINLY TO OUR NORTHWEST. THE GFS CONTINUES TO SHOW THAT THIS FRONT WILL PRODUCE A BAND OF PRECIPITATION AS IT PROGRESSES SOUTHEAST ACROSS THE AREA. MEANWHILE THE GEM AND ECMWF SHOW THAT THIS PRECIPITATION WILL DEVELOP NORTH OF INTERSTATE 94 DURING THE MORNING AND THEN MOVES THROUGH THE REMAINDER OF THE AREA DRY DURING THE AFTERNOON. OVERALL PREFER THE ECMWF AND GEM SOLUTIONS DUE TO THE LACK OF MOISTURE TRANSPORT DURING THE AFTERNOON...AND THAT THE GFS HAS BEEN HAVING A LOT OF ISSUES WITH ITS LOW LEVEL MOISTURE DURING THE PAST MONTH. FROM FRIDAY AFTERNOON THROUGH THE UPCOMING WEEKEND...THE MODELS CONTINUE TO STRUGGLE WITH THEIR TIMING AND LOCATION OF A SERIES OF LOW PRESSURE SYSTEMS MOVING THROUGH THE REGION. MUCH OF THIS IS HOW THEY HAVE BEEN TRYING TO DEVELOP A TROUGH OVER THE WESTERN UNITED STATES AND A RIDGE OVER THE CENTRAL UNITED STATES. OVER THE PAST DAY...THE MODELS HAVE BEEN SLOWING THIS DEVELOPMENT AND THIS HAS KEPT OUR AREA MORE IN ZONAL FLOW ALOFT. AS A RESULT...THE TEMPERATURES HAVE BEEN COOLING OVER THE PAST 4 MODEL RUNS. AS A RESULT...HAD TO INTRODUCE MORE SNOW INTO THE FORECAST FOR THIS TIME PERIOD. WITH THE FIRST SYSTEM /FRIDAY AFTERNOON THROUGH SATURDAY/...THE GFS IS PRODUCING A 6 TO 12 INCH BAND OF SNOW ALONG AND NORTH OF INTERSTATE 94. MEANWHILE THE ECMWF HAS A 3 TO 6 INCH BAND OF SNOW ACROSS FAR NORTHERN WISCONSIN AND UPPER MICHIGAN. THE GFS THEN MOVES YET ANOTHER LOW PRESSURE SYSTEM INTO SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN ON SATURDAY. THE ECMWF ALSO SHOWS ANOTHER LOW PRESSURE SYSTEM...BUT IT DOES NOT AFFECT THE AREA UNTIL MONDAY. THE TEMPERATURES ALOFT LOOK A BIT WARMER...SO THE PRECIPITATION WITH THIS SYSTEM LOOKS TO BE IN THE FORM OF RAIN. && .AVIATION...THROUGH 06Z TUESDAY 1148 PM CDT SUN MAR 31 2013 SURFACE HIGH PRESSURE WILL BUILD SOUTHEAST FROM THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY THROUGH THE TAF PERIOD. NORTHWEST WINDS WILL CONTINUE INTO THE 10 TO 15 KNOT RANGE THROUGH 00Z TUESDAY...THEN DIMINISH AS THE SURFACE HIGH SPREADS EASTWARD INTO THE AREA. SOME PATCHES OF MVFR CLOUDS SEEN ON SATELLITE ACROSS NORTHERN MINNESOTA. MODELS...ESPECIALLY THE NAM AND RAP ARE BOTH OVERDOING THE CURRENT MOISTURE FIELD. DID MENTION SCATTERED CLOUDS WITH BASES BETWEEN 020-030K FEET AFTER 11Z AT KRST AND 15Z AT KLSE. THIS WILL THEN DISSIPATE AFTER 00Z TUESDAY. && .HYDROLOGY...TODAY AND TONIGHT 1235 PM CDT SUN MAR 31 2013 MANY RIVERS HAVE CLIMBED OVER THE PAST FEW DAYS DUE TO RECENT SNOW MELT AND THE RAIN THAT FELL ON SATURDAY WHICH GENERALLY TOTALED UP TO BETWEEN A QUARTER AND THREE QUARTERS OF AN INCH. THERE HAVE BEEN REPORTS OF SOME ROADS BEING CLOSED DUE TO HIGH WATER... PARTICULARLY IN PORTIONS OF SOUTHEAST MINNESOTA WHERE THERE HAD BEEN QUITE A BIT OF SNOW STILL ON THE GROUND LEADING UP TO THIS WEEKEND. APPEARS THAT HIGH WATER LEVELS ARE PAST THEIR PEAKS OVER NORTHEAST IA AND SOUTHWEST WI...AND ARE RIGHT AROUND THEIR PEAK NOW FOR SOUTHEAST MN. WITH THE COOLER WEATHER MOVING IN... ANTICIPATE THAT THE RUNOFF WILL SLOW AND CEASE...ALLOWING THIS WATER TO MOVE OFF DOWNSTREAM. WILL CONTINUE TO MONITOR THE RIVERS CLOSELY. REFER TO THE LATEST STATEMENTS FOR UP-TO-DATE INFO. && .ARX WATCHES/WARNINGS/ADVISORIES... 321 PM CDT SUN MAR 31 2013 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...RABERDING HYDROLOGY....MW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
421 AM MDT MON APR 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM MDT MON APR 1 2013 A SHORTWAVE TROF IS WRAPPING AROUND AN UPR LOW THAT IS OVR THE WRN STATES...AND IS BRINGING CLOUDS AND SOME PCPN TO PORTIONS OF WRN CO...SOME OF WHICH WL AFFECT THE CONTDVD THIS MORNING. ALSO THIS MORNING A FRONT IS CONTINUING TO MOVE SOUTHWARD THROUGH THE SERN PLAINS AS OF 3AM IT HAD MOVED SOUTH OF THE ARKANSAS RIVER VALLEY. HAVE SEEN SOME STRATUS DEVELOP BEHIND THIS FRONT IN NE AND PORTIONS OF NWRN KS. THE HRRR AND NAM12 SHOW LOW LEVEL RH VALUES/STRATUS BACKING INTO THE FAR SERN PLAINS A LITTLE LATER THIS MORNING...AND MAYBE BACKING INTO THE FAR ERN PORTIONS OF EL PASO COUNTY. THE NAM AND THE HRRR KEEP THE FAR SERN PLAINS DRY THRU THE MORNING HOURS...WHILE THE GFS PRINTS OUT SOME LIGHT QPF ASSOCIATED WITH THE STRATUS. DO NOT FEEL THAT MEASURABLE PCPN WL OCCUR SO WL KEEP THE FORECAST DRY OUT EAST...AND WL ONLY HAVE POPS ALONG THE CONTDVD THIS MORNING. THIS AFTERNOON THE NAM AND GFS SHOW THE BEST PCPN CHANCES BEING OVR THE CENTRAL CO MTS AND OVR PIKES PEAK AND TELLER COUNTY. THE NSSL WRF SHOWS PCPN IN THESE AREAS AS WELL...BUT ALSO SHOWS A BAND OF PCPN MOVING FROM THE SW ACRS THE SWRN MTS...THE SAN LUIS VALLEY...THE SANGRE DE CRISTO MTS...AND THEN ONTO THE ADJACENT I-25 CORRIDOR BY EARLY EVENING...AND THEN MOVING ACRS THE SERN PLAINS THRU THE EVENING. WL LEAN CLOSER TO THE WRF`S SOLUTION. SHOULD SEE SOME LIGHT SNOW ACCUMS OVR THE HIGHEST ELEVATIONS. TEMPS TODAY WL BE COOLER THAN YESTERDAY OVR THE SERN PLAINS IN THE WAKE OF THE FRONT...BUT GUIDANCE TEMPS ARE NOT IN GOOD AGREEMENT SO WL SPLIT THE DIFFERENCE. COULD SEE SOME LOW CLOUDS HANGING AROUND OVR THE FAR SERN CORNER INTO THE AFTERNOON WHICH WOULD KEEP TEMPS EVEN COOLER OUT THERE. SOME WRN AREAS WL BE A LITTLE COOLER TODAY...WHILE THE SAN LUIS VALLEY WL LIKELY SEE TEMPS SIMILAR TO THOSE ON SUN. OVERNIGHT THE UPR LOW WL MOVE INTO ERN UT AND MUCH OF THE FORECAST AREA ENDS UP IN THE DRY SLOT...AS SHOW IN THE NAM12...THE NSSL WRF AND THE GFS. THE CENTRAL MTS WL PROBABLY CONTINUE TO HAVE SOME PCPN THRU THE NIGHT...BUT SHOULD GENERALLY BE LIGHT. WITH MOIST LOW LEVEL UPSLOPE OVR THE ERN PLAINS TONIGHT...WIDESPREAD STRATUS IS EXPECTED. THE ONLY AREA THAT ALL THE MODELS SHOW WIDESPREAD PCPN TONIGHT IS OVR THE FAR SERN PLAINS...SO WL GO WITH LIKELY POPS IN THAT AREA...WITH DECREASING POPS WESTWARD TO THE ERN MTS. THE NAM AND GFS SHOW A FEW HUNDREDTHS OF PCPN OVR THE FAR ERN AREAS OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 AM MDT MON APR 1 2013 TUESDAY AND WEDNESDAY...THE UPPER LOW PRES SYSTEM TRACKS FROM THE NW TO THE SE DIRECTLY ACROSS COLORADO ON TUE AND WED...BRINGING A DECENT SHOT AT SOME PCPN FOR THE FORECAST AREA. STARTING OUT TUE MORNING...THE UPPER SYSTEM SHOULD BE PRODUCING SOME SHOWERS FOR THE CENT MTS...WHILE LLVL EASTERLY UPSLOPE FLOW DUE TO SFC HI PRES OVER NE AND KS WILL KEEP A SOLID THREAT OF PCPN FOR THE EASTERN PLAINS. HOWEVER...AS THE UPPER LOW CONTINUES TO TRACK ACROSS THE STATE...PCPN CHANCES SPREAD TO MUCH OF THE AREA BY TUE AFTN AND REMAIN PROBABLE THROUGH THE NIGHT. ONGOING POP GRIDS LOOKED REASONABLE FOR TUE NIGHT AND EARLY WED MORN WITH ONLY SLIGHT ADJUSTMENTS NEEDED. THE TROUGH AXIS EXITS THE SE CORNER OF THE STATE WED MID-MORNING...WITH PCPN THEN TAPERING OFF QUICKLY. AS FOR TEMPS...MAX TEMPS IN THE 40S FOR TUE WILL GRADUALLY WARM INTO THE 50S FOR WED. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT..THE REGION DRIES OUT AS AN UPPER RIDGE OF HIGH PRESSURE MOVES ACROSS THE 4 CORNERS. TEMPS SHOULD REMAIN COOL FOR WED...THEN REBOUND INTO THE MID TO UPPER 60S FOR THU. FRIDAY THROUGH SUNDAY...THE EXTENDED MODELS WANT TO KEEP THINGS A BIT UNSETTLED OVER THE WEEKEND. ONE DISTURBANCE ROLLS ACROSS THE ROCKIES ON FRIDAY BUT LOOKS LIKE IT WILL STAY MAINLY TO THE NORTH OF THE STATE. A BRIEF BREAK ON SAT...THEN SAT NIGHT ANOTHER SHORTWAVE TRACKS ACROSS THE GREAT BASIN AND DIGS FURTHER SOUTH...PROMISING A BETTER SHOT AT SOME BENEFICIAL PCPN. FOR THE TIME BEING...KEPT ISOLATED POPS OVER THE MTS OVER THE WEEKEND AS THE EXTENDED PROCEDURE PRODUCED...AND WILL HAVE TO FINE TUNE AS THAT WINDOW NEARS. FOR THE TIME BEING...FRIDAY LOOKS LIKE THE WARMEST DAY OF THE EXTENDED FORECAST PERIOD. MOORE && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 420 AM MDT MON APR 1 2013 EXPECT VFR CONDITIONS TODAY AT KALS...KPUB AND KCOS. THERE COULD BE A FEW LOW CLOUDS IN THE VCNTY OF KCOS THIS MORNING. EARLY THIS EVENING THERE COULD BE A FEW SHOWERS AND MAYBE EVEN A THUNDERSTORMS AT OR IN THE VCNTY OF KCOS...PROBABLY AFTER 22Z AND BEFORE 03Z. KALS COULD ALSO SEE SOME SHOWERS OR A THUNDERSTORM IN THE AREA...MAINLY AFTER 18Z AND BEFORE 01Z. KALS SHOULD HAVE VFR CONDITIONS TONIGHT. KCOS AND KPUB SHOULD SEE LOW CLOUDS MOVE INTO THE AREA AROUND 06Z WITH IFR CONDITIONS EXPECTED. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...MOORE AVIATION...28
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
340 AM MDT MON APR 1 2013 .SHORT TERM...AN UPPER LEVEL LOW WILL MOVE FROM NEVADA INTO UTAH BY THIS EVENING. AHEAD OF THE LOW THE FLOW ALOFT WILL BE SWLY. AT THE SURFACE HIGH PRES WILL BE OVER THE CNTRL PLAINS WITH LOW PRES OVER WRN COLORADO. THIS WILL LEAD TO SELY LOW LVL FLOW OVER NERN CO THRU TONIGHT. CROSS- SECTIONS SHOW AN INCREASE IN MOISTURE WITH SOME MID LVL QG ASCENT MAINLY LATE TONIGHT. LAPSE RATES ARE BEST OVER THE HIGHER TERRAIN WITH LESS INSTABILITY OVER THE PLAINS. AT THIS TIME THE BEST CHC OF PCPN THRU THIS AFTN LOOKS TO BE IN THE MTNS WITH DRY CONDITIONS OVER THE PLAINS. WILL MENTION SOME THUNDER IN THE MTNS WHERE SOME CAPE EXISTS. HIGHS THIS AFTN OVER NERN CO WILL RANGE FM THE UPPER 40S TO LOWER 50S EXCEPT POSSIBLY ALONG THE FRONT RANGE WHERE SELY LOW LVL WINDS COMING OFF THE PALMER DIVIDE COULD ALLOW FOR READINGS TO RISE INTO THE MID TO UPPER 50S NR DENVER. THE RAP SHOWS HIGHS IN THE LOWER TO MID 60S AROUND DENVER HOWEVER WILL NOT GO THIS WARM. FOR TONIGHT SNOW SHOWERS WILL CONTINUE IN THE MTNS DUE TO INCREASING QG ASCENT HOWEVER SWLY OROGRAPHIC FLOW MAY KEEP ACCUMULATIONS ON THE LIGHT SIDE IN MOST AREAS. EAST OF THE MTNS THE LOW LVL FLOW WILL REMAIN SELY. SHOULD SEE SOME SHOWERS DVLP IN THE FOOTHILLS BY EARLY EVENING WITH SOME OF THE ACTIVITY SPREADING ACROSS THE ADJACENT PLAINS OVERNIGHT. WITH SELY LOW LVL FLOW THE BEST CHC OF PCPN MAY FOCUS IN THE NRN FOOTHILLS AND NORTH OF A DENVER TO LIMON LINE. AT THIS TIME OVERALL CONFIDENCE IS NOT VERY HIGH AS TO WHERE TO MENTION LIKELY POPS OVER THE PLAINS TONIGHT SO WILL KEEP POPS IN THE CHC CATEGORY. SOUNDINGS SHOW WET BULB ZEROS WILL BECOME LOW ENOUGH FOR SHOWERS TO MIX WITH OR CHANGE TO SOME SNOW AFTER MIDNIGHT ACROSS THE PLAINS HOWEVER AT THIS TIME IT LOOKS LIKE ANY ACCUMULATION WILL BE AN INCH OR LESS. .LONG TERM...MODELS HAVE THE UPPER CLOSED LOW OVER EAST CENTRAL UTAH...THEN OVER THE FOUR CORNERS AT 00Z TUESDAY AFTERNOON. BY 18Z WEDNESDAY...ITS OVER SOUTHEASTERN/ WESTERN KANSAS. ON WEDNESDAY NIGHT...INCREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THE FORECAST AREA. THE QG VERTICAL VELOCITY FIELDS HAVE UPWARD MOTION OVER THE CWA TUESDAY AND TUESDAY NIGHT ...HOWEVER IT IS NOT VERY STRONG. WEAK DOWNWARD MOTION IS PROGGED WEDNESDAY AND WEDNESDAY NIGHT. NORTHEAST TO SOUTHEASTERLY LOW LEVEL WINDS ARE PROGGED FOR THE PLAINS AND FOOTHILLS TUESDAY AND TUESDAY EVENING. WEAK FLOW IS PROGGED THE REST OF TUESDAY NIGHT THROUGH WEDNESDAY...WITH A COMBINATION OF NORMAL DUIRNAL PATTERNS TO WEAK DOWNSLOPING WEDNESDAY NIGHT. MOISTURE IS FAIRLY DEEP ON TUESDAY FOR MOST OF THE CWA. IT IS PRETTY DEEP ON THE NAM TUESDAY NIGHT...DRIER ON THE GFS. IT DRIES OUT SOMEWHAT ON WEDNESDAY. THERE IS SOME MOUNTAIN MOISTURE WEDNESDAY NIGHT...BUT ITS DRIER ON THE PLAINS. MODELS SHOW MINOR CAPE OVER THE MOUNTAINS AND FOOTHILLS LATE DAY TUESDAY AND AGAIN WEDNESDAY AFTERNOON. THE QPF FIELDS SHOW MEASURABLE PRECIPITATION TUESDAY AND TUESDAY EVENING FOR MOST AREAS...BEST OVER THE FOOTHILLS AND EASTERN MOUNTIANS ZONES. THERE IS A TAD THE REST OF TUESDAY NIGHT AND WEDNESDAY... MAINLY OVER THE MOUNTIANS. FOR POPS...WILL KEEP THE "LIKELY"S IN OVER THE MOUNTAINS AND "CHANCES" OUT ON THE PLAINS TUESDAY AND TUESDAY EVENING. THE PLAINS WILL SEE BOTH SNOW AND RAIN...WITH LITTLE ACCUMULATION. WILL DECREASE POPS THE REST OF TUESDAY NIGHT. ON WEDNESDAY...JUST SOME MINOR ALPINE POPS. WILL PUT "ISOLATED" THUNDER IN BOTH TUESDAY AND WEDNESDAY AFTERNOONS IN THE MOUNTIANS. FOR TEMPERATURES...TUESDAY`S HIGHS ARE 2.0-3.5 C COOLER THAN TODAY`S EXPECTED HIGHS. WEDNESDAY`S READINGS COME UP 3-7 C FROM TUESDAY`S. FOR THE LATER DAYS...THURSDAY THROUGH SUNDAY...MODELS HAVE UPPER RIDGING FOR COLORADO THROUGH MID DAY FRIDAY...THEN A WEAK UPPER TROUGH IS PROGGED ACROSS THE STATE BY EARLY SATURDAY MORNING. AFTER THAT...WEST-SOUTHWESTERLY FLOW ALOFT IS PROGGED OVER THE CWA THROUGH SUNDAY. THERE IS LIMITED MOISTURE AROUND...BUT IT INCREASES ON SUNDAY. && .AVIATION...SO FAR ANY STRATUS WAS CONFINED TO THE FAR NERN CORNER OF THE PLAINS SO AT THIS POINT IT DOES NOT APPEAR IT WILL AFFECT THE AIRPORT THIS MORNING. AS FOR WINDS BOTH THE RAP AND HRR SHOW A DENVER CYCLONE DEVELOPING SW OF DENVER WITH WINDS BEING E TO SE THRU THE AFTN. COULD SEE SUSTAINED WINDS IN THE 15 TO 20 MPH BY 20Z. AT THIS TIME ANY CHC FOR RAIN SHOWERS WILL BE AFTER 00Z. COULD SEE SHOWERS CHANGE TO SOME SNOW AFTER MIDNIGHT BUT ANY ACCUMULATION WILL BE UNDER ONE HALF INCH AND CONFINED TO GRASSY AREAS. LATEST NAM CONTINUES TO SHOW A CYCLONE OVERNIGHT OVER DENVER WITH WINDS BECOMING MORE SLY AFTER MIDNIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM....RJK AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MIAMI FL
1031 AM EDT MON APR 1 2013 .UPDATE... THE MORNING SURFACE ANALYSIS SHOWED A HIGH PRESSURE RIDGE AXIS EXTENDING WEST ACROSS SOUTH FLORIDA AND THE SOUTHEAST GULF OF MEXICO AND A COLD FRONT APPROACHING FROM THE NORTH. SSW LOW-LEVEL FLOW IS EXPECTED TO GRADUALLY VEER TOWARD THE WEST THROUGH THE COURSE OF THE DAY AS THIS BOUNDARY CONTINUES SOUTH. THIS FLOW COMBINED WITH THE AFTERNOON EAST COAST SEA BREEZE...A COUPLE OF IMPULSES ALOFT AND MODERATE INSTABILITY AND SHEAR (0-6KM 30-35 KT) COULD GENERATE A FEW STRONG TO EVEN SEVERE THUNDERSTORMS THROUGH THE AFTERNOON/EVENING PERIOD TODAY OVER THE METRO/EAST COAST LOCATIONS. THE LATEST WRF AND HRRR MODEL REFLECTIVITIES... HOWEVER...ARE ONLY INDICATING ISOLATED COVERAGE OVER THESE AREAS AT BEST THROUGH THIS TIME. ANY STORMS THAT DO INITIATE COULD BE CAPABLE OF PRODUCING STRONG WINDS, HAIL AND POSSIBLY A TORNADO. THE LATEST FORECAST HAS BEEN UPDATED TO REFLECT THIS POTENTIAL THIS AFTERNOON. ELSEWHERE...VISIBILITIES HAVE BEGUN TO IMPROVE OVER THE PAST HOUR ACROSS THE INTERIOR LOCATIONS FROM THE EARLY MORNING FOG AND THIS TREND IS EXPECTED TO CONTINUE. THE LOCAL OFFICIALS HAVE REPORTED THAT SEGMENTS OF I-75 HAVE BEEN CLOSED TODAY DUE TO A COMBINATION OF THIS FOG EARLIER AND SMOKE FROM THE ONGOING WILDFIRE IN COLLIER COUNTY. && .PREV DISCUSSION... /ISSUED 739 AM EDT MON APR 1 2013/ AVIATION... AN UPPER LEVEL SHORTWAVE ACROSS THE EASTERN GULF WILL MOVE ACROSS THE FLORIDA PENINSULA TODAY. A FEW SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MAINLY TO THE EAST OF THE EAST COAST TAF SITES THIS MORNING. SEA BREEZE BOUNDARIES EARLY THIS AFTERNOON ARE EXPECTED TO HELP GENERATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NEAR THE EAST COAST TAF SITES. SO ADDED VCTS FOR THE EAST COAST TAFS. FOR KAPF...THERE IS A SLIGHT CHANCE OF SHOWERS AHEAD OF THE TROUGH...MAINLY BEFORE 18Z. WIND DIRECTION MAY VARY BETWEEN 160-210 DEGREES DURING THE DAY AT THE EAST COAST TAF SITES. WINDS WILL SHIFT TO THE WEST TO NORTHWEST TONIGHT BEHIND THE BOUNDARY. PREV DISCUSSION... /ISSUED 459 AM EDT MON APR 1 2013/ DISCUSSION... CURRENTLY, A MID LEVEL TROUGH, ROUGHLY AT 700 MB, IS MOVING ACROSS THE EASTERN GULF OF MEXICO. THIS HAS GENERATED A LINE OF THUNDERSTORMS THAT IS EXPECTED TO FALL APART AS IT APPROACHES CENTRAL FLORIDA. THIS TROUGH, ACCORDING TO THE HRRR, MAY SPARK OFF A FEW SHOWERS OVER SOUTH FLORIDA THIS MORNING. ALSO, ANOTHER SHORT WAVE HAS GENERATED SOME SHOWERS AND ISOLATED THUNDERSTORMS OVER THE FLORIDA STRAITS. THESE ARE MOVING NORTH NORTHEAST. THE SHOWERS WILL AFFECT THE SOUTHEASTERN PORTION OF THE CWA THIS MORNING. THE QUESTION IS IF THERE WILL BE ANY THUNDERSTORMS THAT MOVE INTO THE AREA AS WELL. THERE IS AROUND 1000 JOULES JUST ONSHORE, AROUND HOMESTEAD AND MIAMI. SO, ALTHOUGH ORIGINAL THINKING WAS THEY WOULD STAY OFFSHORE, MAY HAVE TO ADD A MENTION OF THUNDERSTORMS FOR THIS AREA THIS MORNING. AS FOR LATER TODAY, MODELS INDICATE THE TROUGH, OR REALLY, A WEAKENING FRONT, WILL MOVE ONSHORE THE GULF COAST LATER THIS MORNING. MODELS ARE INDICATING IT WILL NOT BE TOO ACTIVE, CONVECTION WISE WHEN IT DOES. BUT, AS IT PROGRESS ACROSS THE STATE, ALONG WITH DAYTIME HEATING, CONVECTION MAY BE ABLE TO INITIATE. THE MODELS DO DIFFER GREATLY WITH HOW MUCH CAPE WILL BE AVAILABLE. THE GFS KEEPS THE HIGHEST BOUNDARY LAYER CAPE VALUES WELL OFFSHORE AND ONLY 500-600 JOULES OVER THE ATLANTIC COAST. THE NAM, ON THE OTHER HAND, HAS 1200 TO 1600 JOULES OVER THE ATLANTIC COAST, NEAT WEST PALM BEACH, AND DROPS TO 500-700 JOULES NEAR MIAMI. NOW THE NAM MODEL SOUNDINGS HAVE 1200-1600 JOULES ALL OVER THE ATLANTIC COAST. THEY DO SHOW A WEAK CAP FURTHER NORTH, BUT IT IS SO WEAK, NOT THINKING IT WILL BE A REAL INHIBITOR. THERE IS ALSO A TOUCH OF CIN TO THE NORTH AS WELL, BUT AGAIN, NOTHING THAT REALLY SHOULD INHIBIT DEVELOPMENT. SO, WHAT WILL INHIBIT THEIR DEVELOPMENT. WELL, MODELS DO SHOW THAT THE CAPE WILL BE PUSHING OFF TO THE EAST, AHEAD OF THE TROUGH. SO, WE MAY BE LACKING THE LIFTING MECHANISM. IT MAY ARRIVE WELL AFTER THE CAPE HAS PUSHED OFF SHORE. SO, HAVE KEPT CHC POPS AND SLIGHT CHC TSTMS, BUT HAVE BROADENED THE COVERAGE OF TSTMS THIS AFTERNOON. BEHIND THE TROUGH TODAY, HIGH PRESSURE WILL BE BUILDING IN FAIRLY QUICK. THIS WILL BRING QUIET WEATHER BACK TO SOUTH FLORIDA FOR A FEW DAYS. FOR FRIDAY AND THE WEEKEND, A LOW PRESSURE SYSTEM WILL DEVELOP OVER THE WESTERN GULF AND MOVE OVER THE FLORIDA PANHANDLE THURSDAY NIGHT/FRIDAY MORNING. A COLD FRONT WILL MOVE THROUGH SOUTH FLORIDA FRIDAY. THIS SYSTEM WILL BRING OUR NEXT CHANCE FOR RAIN AND POSSIBLY A THUNDERSTORM. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE STRENGTH, POSITION, AND TIMING OF THIS SYSTEM. GIVEN THIS, HAVE A HIGH CHC POP IN THE FORECAST FOR FRIDAY. BEHIND THE FRONT, HIGH PRESSURE WILL BUILD IN ONCE AGAIN. TEMPERATURES WILL NOT BE MUCH COOLER, ONLY A FEW DEGREES. THIS HIGH PRESSURE WILL LAST FOR THE REMAINDER OF THE EXTENDED FORECAST. MARINE... WINDS AHEAD OF A WEAK FRONT/TROUGH WILL PICK UP OUT OF THE SOUTH TO BETWEEN 13 AND 19 KTS OVER THE ATLANTIC WATERS. THEY SHOULD REMAIN BELOW 10 KTS OVER THE GULF WATERS. THE HIGHER WIND SPEEDS OVER THE ATLANTIC WATERS HAS PROMPTED A SMALL CRAFT SHOULD EXERCISE CAUTION STATEMENT FOR THIS AFTERNOON. SEAS TODAY WILL BE SUBSIDING SOMEWHAT, EVEN WITH THE WINDS, AND ARE EXPECTED TO BE 1 TO 3 FEET BY TOMORROW IN THE ATLANTIC WATERS. THE GULF WATERS WILL BE AROUND 1 FOOT FOR THE NEXT COUPLE OF DAYS. HIGH PRESSURE WILL BUILD IN BEGINNING TONIGHT. THIS WILL CAUSE WINDS TO WEAKEN SOME TONIGHT TO 7-10 KTS OVER THE ATLANTIC AND SHIFT THEM OUT OF THE NORTH TOMORROW. FIRE WEATHER... THE MAIN FIRE WEATHER CONCERN TODAY ARE THE SHIFTING WINDS. AN APPROACHING FRONT/TROUGH WILL CAUSE WINDS TO PICK UP SOME TODAY TO 10 TO 15 MPH OVER GLADES, HENDRY, AND INTERIOR COLLIER COUNTIES. THEY WILL BEGIN OUT OF THE SOUTHEAST, BUT TURN THROUGH THE DAY TO THE SOUTH, THEN SOUTHWEST BY EARLY AFTERNOON. BY THIS EVENING, THEY WILL BECOME WESTERLY BETWEEN 5 AND 10 MPH. ALONG WITH THIS WIND SHIFT, WILL BE THE CHANCE FOR SOME RAIN SHOWERS AND A SLIGHT CHANCE FOR A THUNDERSTORM. THE CHANCES INCREASE AS YOU GO EASTWARD ACROSS SOUTH FLORIDA. IN THE INTERIOR PORTION OF THE AREA, THE DIVIDING LINE FOR THE CHANCE OF AND THUNDERSTORMS IS A DIFFICULT ONE AT BEST. SO, AREAS WEST OF THE FORECASTED AREA, SHOULD REMAIN AWARE OF THE POSSIBILITY THAT THE FORECAST COULD CHANGE TO INCLUDE THEM AS THE TROUGH GETS CLOSER. ONE THE OTHER HAND, IT COULD ALSO BE PUSHED FURTHER EAST. THERE IS JUST GREAT UNCERTAINTY WITH THE CONVECTIVE DEVELOPMENT TODAY. BEHIND THE TROUGH, HIGH PRESSURE WILL BUILD IN THROUGH THURSDAY, BRINGING QUIET WEATHER BACK TO SOUTH FLORIDA. PREV DISCUSSION... /ISSUED 241 AM EDT MON APR 1 2013/ AVIATION... ISOLATED SHOWERS WERE MOVING ACROSS THE ATLANTIC WATERS AND NEAR KFLL AND FXE. ANOTHER AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS WERE MOVING JUST SOUTH OF THE KEYS. THIS AREA OF SHOWERS AND STORMS WILL CONTINUE TO MOVE NORTHWARD OVERNIGHT...AND COULD GET NEAR KTMB AND KMIA IN THE NEXT FEW HOURS IF THEY HOLD TOGETHER. A SHORTWAVE TROUGH MOVING ACROSS THE EASTERN GULF WAS FORCING SHOWERS AND THUNDERSTORMS TO DEVELOP WEST OF TAMPA. THE HRRR KEEPS THIS LINE TOGETHER AND MOVES IT TOWARDS KAPF AROUND 16Z. OTHER SHOWERS OR STORMS COULD ALSO BEGIN DEVELOPING ON THE EAST COAST SEA BREEZE AROUND THIS TIME. THE WIND DIRECTION IS ALSO TRICKY TODAY AS THE BOUNDARY LAYER WINDS SHIFT TO THE SOUTHWEST AHEAD OF THE TROUGH AND WEAK COLD FRONT. SO THE WINDS MAY SHIFT TO THE SOUTHWEST FOR A TIME LATE IN THE MORNING BEFORE THE EAST COAST SEA BREEZE BOUNDARY TRIES TO PUSH THE WINDS BACK TO THE SOUTH OR SOUTHEAST. BY 00Z...SOUTHWESTERLY FLOW IS EXPECTED TO PREVAIL...WITH WEST TO NORTHWESTERLY FLOW BEHIND THE SURFACE TROUGH AFTER 02-04Z. SO FOR THE TAFS...KEPT VCSH FOR NOW...BUT MAY NEED TO ADD VCTS. MVFR CONDITIONS ARE POSSIBLE NEAR ANY SHOWERS OR STORMS THAT FORM. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 82 65 81 68 / 50 20 10 - FORT LAUDERDALE 82 66 82 69 / 50 20 10 - MIAMI 82 67 83 69 / 50 20 10 - NAPLES 79 63 79 63 / 20 10 10 - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
635 AM EDT MON APR 1 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 353 AM EDT MON APR 1 2013 A WEAK UPPER WAVE WILL MOVE THROUGH THE AREA THIS MORNING BUT HIGH PRESSURE WILL BUILD IN THIS AFTERNOON AND KEEP DRY WEATHER ACROSS THE AREA THROUGH SATURDAY. SATURDAY NIGHT A LOW PRESSURE SYSTEM WILL APPROACH AND BRING CHANCES FOR RAIN. TEMPERATURES WILL BE WELL BELOW NORMAL TODAY THROUGH TUESDAY NIGHT AND THEN REBOUND TO ABOVE NORMAL BY THE WEEKEND. && .NEAR TERM /TODAY/... ISSUED AT 353 AM EDT MON APR 1 2013 FORECAST FOCUS IS ON NEED FOR ANY POPS FROM EARLY TO MID MORNING. UPPER WAVE IS CURRENTLY MOVING SOUTHEAST THROUGH SOUTHERN IOWA AND WESTERN ILLINOIS. RADAR MOSAIC SHOWS WEAK ECHOES OVER WESTERN AND CENTRAL ILLINOIS AS WELL AS SOME ENTERING WESTERN INDIANA BUT SURFACE OBS SHOW NO PRECIP AT THE GROUND. GFS AND NAM ARE BOTH DRY AND GUIDANCE IS AS WELL. RAPID REFRESH AND RAP SHOW SOME DEVELOPMENT OCCURRING ACROSS THE SOUTHERN COUNTIES AROUND 11-12Z AND MOVING THROUGH BY 15Z. WITH BOTH OF THE RAPID UPDATE MODELS SHOWING THIS DEVELOPMENT WILL GO AHEAD AND LEAVE A SLIGHT CHANCE FOR RAIN AND SNOW MOVING ACROSS THE SOUTH FROM 11 TO 15Z AND DRY FROM 15Z ON. SHOULD NOT AMOUNT TO ANYTHING. WILL DROP ANY MENTION OF FLURRIES ELSEWHERE. CLOUDS SHOULD SCATTER OUT AS THE DAY GOES ON. WILL SEE COLD ADVECTION THROUGHOUT THE DAY SO TEMPERATURES SHOULD STRUGGLE TO WARM AND THUS WENT WITH A CONSENSUS OF RAW MODEL NUMBERS SINCE CLIMATOLOGY COULD BIAS THINGS UP. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 353 AM EDT MON APR 1 2013 HIGH PRESSURE WILL DOMINATE THE WEATHER IN THE SHORT TERM. MODELS ARE IN GOOD AGREEMENT AND WILL USE A CONSENSUS. WITH MOSTLY CLEAR TO CLEAR SKIES THROUGHOUT THE SHORT TERM STUCK CLOSE TO COOLER GUIDANCE NUMBERS AT NIGHT OF LOW TO MIDDLE 20S. FOR HIGHS TUESDAY AGAIN THOUGHT GUIDANCE WAS BIASED A BIT WARM FROM CLIMATOLOGY SO STUCK WITH A RAW MODEL CONSENSUS IN THE LOW TO MID 40S...BUT BY WEDNESDAY THE AIR MASS SHOULD BE REBOUNDING UNDER WARM ADVECTION AND A COMPLETE CONSENSUS LOOKED GOOD IN THE UPPER 40S TO LOW 50S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 324 AM EDT MON APR 1 2013 A LARGE AREA OF HIGH PRESSURE WILL BE MOVING AWAY TO THE EAST ON THURSDAY WITH A SPLIT FLOW PATTERN ALOFT AS A WEAK FRONT APPROACHES FROM THE NORTHWEST AND AN UPPER LOW TRACKS ACROSS THE SOUTHERN PLAINS. MODEL CONSENSUS HAS BEEN TRACKING THE UPPER WAVE FURTHER NORTH OVER THE LAST COUPLE DAYS AND BRINGS THE NORTHERN FRINGES OF THE RAINFALL ASSOCIATED WITH THE UPPER LOW INTO THE OHIO RIVER VALLEY THURSDAY NIGHT. CONSIDERING THE NORTHERLY LOW LEVEL FLOW...PRESENCE OF DRIER AIR OVER THE REGION AND THE BULK OF THE DEEPER FORCING REMAINING TO THE SOUTH OF THE FORECAST AREA...WILL CONTINUE TO KEEP A DRY FORECAST GOING THURSDAY NIGHT. DO ANTICIPATE AN INCREASE IN CLOUDS OVER THE SOUTHERN COUNTIES THURSDAY NIGHT AND EARLY FRIDAY AS THE UPPER WAVE PASSES TO THE SOUTH. THE AFOREMENTIONED WEAK FRONT APPROACHING FROM THE NORTHWEST SET TO WASH OUT ACROSS THE LOWER GREAT LAKES THURSDAY NIGHT. AS THE UPPER WAVE WEAKENS AND SHIFTS INTO THE SOUTHEAST STATES BY FRIDAY AFTERNOON...HIGH PRESSURE WILL REESTABLISH ACROSS THE OHIO VALLEY WITH AN EXPANSION OF RIDGING ALOFT BRINGING WARMER AIR INTO THE REGION. LOW LEVEL THERMALS SUPPORT HIGH TEMPS RISING INTO THE 60S BY SATURDAY. FORECAST MORE MUDDLED FOR THE SECOND HALF OF THE WEEKEND AS A DEVELOPING WARM FRONT SETS UP OVER THE LOWER GREAT LAKES AND A SURFACE WAVE TRACKS ALONG THE BOUNDARY ON SUNDAY. WILL CARRY LOW CHANCE POPS SATURDAY NIGHT INTO SUNDAY AS THE SURFACE WAVE PASSES THROUGH THE AREA. APPEARS THE BOUNDARY MAY SETTLE FURTHER SOUTH NEAR THE OHIO RIVER BY LATE SUNDAY WITH THE PASSAGE OF THE LOW...BEFORE THE BOUNDARY RETURNS BACK NORTH EARLY NEXT WEEK. LOW LEVEL THERMALS STILL SUGGESTIVE OF HIGHS IN THE 60S FOR SUNDAY EVEN AS THE BOUNDARY SHIFTS SOUTH...WITH POSSIBILITY FOR WARMER DAYTIME HIGHS EARLY NEXT WEEK ONCE THE FRONT LIFTS BACK NORTH. && .AVIATION /DISCUSSION FOR 011200Z TAF ISSUANCE/... ISSUED AT 635 AM EDT MON APR 1 2013 VFR CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST PERIOD. MID LEVEL CLOUDS PRESENT EARLY THIS MORNING AS AN UPPER WAVE MOVES THROUGH THE REGION. AREA OF RETURNS NOTED FROM WESTERN INDIANA BACK INTO ILLINOIS BUT APPEARS LITTLE IF ANY OF THIS IS REACHING THE GROUND BASED ON CURRENT OBS. MAY SEE A FEW FLURRIES AT KBMG/KHUF/KIND THROUGH 15Z BUT EXPECT NO IMPACTS TO TERMINALS. MODEL SOUNDINGS SHOW FAVORABLE CONDITIONS FOR CU DEVELOPMENT THIS AFTERNOON WITH CONVECTIVE TEMPS IN THE UPPER 30S AND INCREASING COLD ADVECTION. LIKELY TO SEE GUSTS TO AROUND 20KTS AS WELL THROUGH THE AFTERNOON WITH GOOD LOW LEVEL MIXING. AS HIGH PRESSURE SPREADS INCREASINGLY DRIER AIR INTO THE FORECAST AREA...WILL SEE A GRADUAL DECREASE IN CU BY LATE DAY WITH SKIES BECOMING MOSTLY CLEAR TONIGHT.NORTHWEST WINDS WILL BECOME LIGHT THIS EVENING. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....RYAN AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS WICHITA KS
1013 AM CDT MON APR 1 2013 .UPDATE... ISSUED AT 1013 AM CDT MON APR 1 2013 SENT OUT A QUICK UPDATE TO KEEP UP WITH CURRENT PRECIP TRENDS. ISENTROPIC LIFT ALONG THE 305K SURFACE HAS RESULTED IN PRECIP EXPANDING OVER SW PORTIONS OF THE FORECAST AREA. THIS ACTIVITY SHOULD CONTINUE TO PUSH EAST LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS. A COUPLE RUMBLES OF THUNDER MAY MIX WITH THE SHOWERS. LAWSON && .SYNOPSIS... ISSUED AT 332 AM CDT MON APR 1 2013 A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE FIRST PART OF THE WEEK. && .SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT) ISSUED AT 332 AM CDT MON APR 1 2013 THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE. THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN. BILLINGS .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 332 AM CDT MON APR 1 2013 BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST. SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S. TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY. ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS THE TIME PERIOD NEARS. BILLINGS && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 648 AM CDT MON APR 1 2013 A SHARP COLD FRONT HAS ALREADY MOVED ACROSS MOST LOCATIONS THIS MORNING EXPECT SOME GUSTY WINDS TO 25 KTS FOR A FEW HOURS AFTER THE FRONT MOVES THROUGH. WILL ALSO SEE SOME POST FRONTAL MVFR CEILINGS ALSO DROP SOUTH ACROSS THE REGION FOR A FEW HOURS AFTER THE FRONT PASSES...WITH CEILINGS OF 1500 FT AGL. EXPECT THIS MVFR CLOUD DECK TO BE SHORT LIVED....WITH LOWER CLOUDS STAYING AROUND FOR ONLY 4 OR 5 HOURS. LIFT OVER THE TOP OF THE SHALLOW COLD AIR ACROSS SRN KS...WILL LEAD TO A CHANCE OF SOME LIGHT RAIN SHOWERS FOR MAINLY SRN KS. SO WILL INCLUDE A VCSH FOR THE KICT/KHUT AND KCNU TAF SITES AFTER 22Z/MON. WILL SEE MORE OF WIDESPREAD LIGHT RAIN CHANCE DEVELOP LATE TNGT INTO TUE AM...AFTER 12Z TUE. COULD ALSO SEE CEILINGS DROP TO LOW MVFR OR POSSIBLY IFR ACROSS SRN KS ON TUE....BUT THIS IS BEYOND THIS TAF TIME FRAME. KETCHAM && .FIRE WEATHER... ISSUED AT 332 AM CDT MON APR 1 2013 VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST. LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW. WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND FIRE DANGER WILL BE VERY HIGH. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 51 35 43 35 / 40 60 50 30 HUTCHINSON 50 33 45 32 / 30 40 40 20 NEWTON 51 32 43 31 / 20 30 30 20 ELDORADO 51 33 44 33 / 30 40 40 20 WINFIELD-KWLD 53 36 42 36 / 40 70 70 40 RUSSELL 51 30 48 30 / 10 30 20 10 GREAT BEND 50 31 46 31 / 20 30 30 20 SALINA 52 31 50 33 / 10 20 10 10 MCPHERSON 51 32 46 32 / 20 30 20 10 COFFEYVILLE 55 37 44 36 / 30 60 70 40 CHANUTE 53 34 44 34 / 20 30 30 10 IOLA 52 33 45 33 / 20 20 20 10 PARSONS-KPPF 53 35 44 35 / 30 50 50 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
651 AM CDT MON APR 1 2013 .SYNOPSIS... ISSUED AT 332 AM CDT MON APR 1 2013 A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE FIRST PART OF THE WEEK. && .SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT) ISSUED AT 332 AM CDT MON APR 1 2013 THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE. THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN. BILLINGS .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 332 AM CDT MON APR 1 2013 BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST. SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S. TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY. ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS THE TIME PERIOD NEARS. BILLINGS && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 648 AM CDT MON APR 1 2013 A SHARP COLD FRONT HAS ALREADY MOVED ACROSS MOST LOCATIONS THIS MORNING EXPECT SOME GUSTY WINDS TO 25 KTS FOR A FEW HOURS AFTER THE FRONT MOVES THROUGH. WILL ALSO SEE SOME POST FRONTAL MVFR CEILINGS ALSO DROP SOUTH ACROSS THE REGION FOR A FEW HOURS AFTER THE FRONT PASSES...WITH CEILINGS OF 1500 FT AGL. EXPECT THIS MVFR CLOUD DECK TO BE SHORT LIVED....WITH LOWER CLOUDS STAYING AROUND FOR ONLY 4 OR 5 HOURS. LIFT OVER THE TOP OF THE SHALLOW COLD AIR ACROSS SRN KS...WILL LEAD TO A CHANCE OF SOME LIGHT RAIN SHOWERS FOR MAINLY SRN KS. SO WILL INCLUDE A VCSH FOR THE KICT/KHUT AND KCNU TAF SITES AFTER 22Z/MON. WILL SEE MORE OF WIDESPREAD LIGHT RAIN CHANCE DEVELOP LATE TNGT INTO TUE AM...AFTER 12Z TUE. COULD ALSO SEE CEILINGS DROP TO LOW MVFR OR POSSIBLY IFR ACROSS SRN KS ON TUE....BUT THIS IS BEYOND THIS TAF TIME FRAME. KETCHAM && .FIRE WEATHER... ISSUED AT 332 AM CDT MON APR 1 2013 VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST. LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW. WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND FIRE DANGER WILL BE VERY HIGH. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 51 35 43 35 / 40 60 50 30 HUTCHINSON 50 33 45 32 / 30 40 40 20 NEWTON 51 32 43 31 / 30 30 30 20 ELDORADO 51 33 44 33 / 30 40 40 20 WINFIELD-KWLD 53 36 42 36 / 40 70 70 40 RUSSELL 51 30 48 30 / 20 30 20 10 GREAT BEND 50 31 46 31 / 20 30 30 20 SALINA 52 31 50 33 / 20 20 10 10 MCPHERSON 51 32 46 32 / 30 30 20 10 COFFEYVILLE 55 37 44 36 / 40 60 70 40 CHANUTE 53 34 44 34 / 30 30 30 10 IOLA 52 33 45 33 / 30 20 20 10 PARSONS-KPPF 53 35 44 35 / 30 50 50 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
927 AM EDT MON APR 1 2013 .SYNOPSIS... NORTHWEST WINDS WILL PROVIDE BELOW NORMAL TEMPERATURES THROUGH MIDWEEK. AN UPPER LEVEL SYSTEM WILL BRING THE RISK FOR RAIN OR SNOW SHOWERS TODAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A MIX OF RAIN AND SNOW SHOWERS CONTINUE TO CROSS THE REGION ALONG AND BEHIND THE COLD FRONT THIS MORNING. HAVE BUMPED UP THE POPS ACCORDINGLY USING RUC DATA THAT SEEMS TO BE HANDLING THE TIMING AND SCATTERED NATURE OF THE SHOWERS QUITE WELL. TEMPERATURES AHEAD OF THIS BOUNDARY HAVE WARMED UP SLIGHTLY BUT THIS WILL BE BRIEF AS COLD ADVECTION SHOULD GENERALLY KEEP A DOWNWARD TREND IN TEMPS DURING THE DAY. LATEST MODEL SOUNDINGS ARE SHOWING A DRY AIR MASS SETTLING IN THE LOWER LEVELS THIS AFTERNOON. THIS WILL LIMIT LAKE EFFECT /UP-SLOPE SNOW SHOWER DEVELOPMENT. THE HIGHEST RIDGES WILL HAVE THE BEST CHANCE TO SEE MORE NUMEROUS SNOW SHOWERS AS ELEVATION WILL KEEP THEM IN A THE SATURATED LAYER. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... OUR BRIEF ACQUAINTANCE WITH SPRING WILL SADLY DEPART AS WE ONCE AGAIN RETURN TO A PATTERN MORE REMINISCENT OF WINTER WITH THE EASTERN HALF OF THE CONUS UNDER THE INFLUENCE OF A LARGE UPPER LEVEL TROUGH THROUGH MUCH OF THE PERIOD. WHILE THE UPPER LEVEL FLOW MAY KEEP A SLIGHTLY MORE WESTERLY THAN NORTHWESTERLY COMPONENT...SHORTWAVES DIVING THROUGH THE COLD UPPER LEVEL FLOW SHOULD PROVIDE AT LEAST CLOUD COVER THROUGH LATE TUESDAY AND SOME LAKE ENHANCED SNOW SHOWERS POSSIBLE IMMEDIATELY DOWNWIND OF LAKE ERIE...THOUGH IT IS QUESTIONABLE TO WHETHER IT WILL REALLY IMPACT OUR NORTHERN ZONES VERY MUCH. BY WEDNESDAY...MODELS SHOW A FEW INCONSISTENCIES IN THE PLACEMENT AND STRENGTH OF A SHORTWAVE DIVING THROUGH THE TROUGH AND ITS IMPACT TO THE REGION. AS SUCH...OPTED TO REMAIN CLOSER TO THE ENSEMBLE MEANS WHICH KEEP THE REGION DRY. EVEN FOR THE START OF APRIL....COLD ADVECTION AND CLOUD COVER SHOULD KEEP TEMPERATURES BELOW SEASONAL AVERAGES THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MODEL AND ENSEMBLE SOLUTIONS ALL FAVOR A DRY EXTENDED FORECAST WITH LOW PRES SUPPRESSED TO OUR SOUTH IN THE SPLIT FLOW PATTERN LATE IN THE WEEK. HOWEVER...AS THE PRECIP SHIELD OF THAT SYSTEM MAY CLIP THE SOUTHEASTERN PORTIONS OF THE FORECAST AREA...HAVE INCLUDED SLGT TO CHC POPS FOR FRIDAY INTO FRIDAY NIGHT. HIGH PRESSURE IS CURRENTLY TIMED TO BRING DRY WEATHER FOR SATURDAY....BUT ANOTHER FRONT MAY BRING A CHANCE OF SHOWERS FOR SUNDAY.. TEMPERATURES THROUGH THE EXTENDED MODERATE TOWARD AVERAGE. 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 OF TEMPS ARE ANTICIPATED. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... A RELATIVELY DRY COLD FRONT WILL CROSS THE TERMINALS THIS MORNING...BRINGING A WIND SHIFT FROM SOUTHWESTERLY TO NORTHWESTERLY WITH ITS PASSAGE. THE FRONT WILL CROSS THE TERMINALS BETWEEN 09Z AND 13Z. WINDS BEHIND THE FRONT WILL INCREASE TO AROUND 15KTS WITH GUSTS UP TO 25KTS LATE THIS MORNING INTO THE AFTERNOON. WITH LITTLE PRECIPITATION EXPECTED OTHER THAN A STRAY SPRINKLE OR FLURRY...VFR CONDITIONS ARE FORECAST ACROSS MOST OF THE TERMINALS THROUGH THE TAF PERIOD. THE EXCEPTION IS AT KFKL/KDUJ...WHERE TEMPO GROUPS ARE FORECAST FOR MVFR CEILINGS LATE THIS MORNING. .OUTLOOK.../TUESDAY THROUGH FRIDAY/... A COLD NORTHWESTERLY FLOW WILL LEAD TO POSSIBLE RESTRICTIONS AT KFKL/KDUJ ON TUESDAY AND TUESDAY NIGHT. OTHERWISE...GENERAL VFR CONDITIONS CAN BE EXPECTED THROUGH THURSDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE REGION. A LOW PRESSURE SYSTEM PASSING SOUTH OF THE AREA MAY BRING RAIN TO LOCATIONS SOUTH OF KPIT ON FRIDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
952 AM EDT MON APR 1 2013 .SYNOPSIS... ISSUED AT 422 AM EDT MON APR 1 2013 A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER MICHIGAN. && .UPDATE... ISSUED AT 951 AM EDT MON APR 1 2013 THE STORM SYSTEM WHICH SWEPT ACROSS THE GREAT LAKES THIS WEEKEND... HAS PUSHED EAST OF THE STATE AND WILL CONTINUE TO LIFT INTO QUEBEC THROUGH TUESDAY. COLD 850MB TEMPS...NORTHWEST WINDS AND LAKE EFFECT SNOWS HAD ALREADY BEGUN TO FILTER INTO NRN MI EARLIER THIS MORNING. 850MB TEMPS DROPPED FROM AROUND 0C SUNDAY AFTERNOON TO ARND -16C BY 12Z THIS MORNING. AS FOR THE REST OF THE AFTN...THE PARAMETERS WHICH ARE CURRENTLY GENERATING LAKE INDUCED SNOWS OVER THE WRN LAKES...ARE NOT EXPECTED TO CHANGE MUCH THROUGH 21Z. 850MB TEMPS WILL LINGER AROUND -16C AS THE AXIS OF THE SFC AND 500MB FEATURES PUSH FURTHER EAST OF THE REGION THIS AFTERNOON. SFC-850MB WINDS WOBBLE DURING THE AFTN...THOUGH REMAIN GENERALLY NW (300-320) WHILE INVERSION HEIGHTS LINGER AROUND 5K FT. OVERALL EXPECT WIDESPREAD LAKE SNOWS TO CONT OVER THE WRN LAKES THROUGH THE AFTN...THOUGH WITH THE HIGH SUN ANGLE...EXPECT DOMINATE SNOW BANDS TO BECOME A LEAST SLIGHTLY DISRUPTED THROUGH THE REST OF THE MORNING. OVERALL WILL KEEP CONT TO MENTION LAKE SNOWS THROUGH THE AFTN. WILL MENTION UP TO 2 INCHES OF SNOW POSSIBLE IN FAVORED SNOW BELTS...AND WILL EXTEND HEADLINES THRU THE AFTN. UPDATE ISSUED AT 708 AM EDT MON APR 1 2013 CHANGES THIS HOUR: ADDITIONAL /UPWARD/ ADJUSTMENTS TO SNOWFALL AS A BAND OF NEARLY 5 INCHES HAS OCCURRED OVER EXTREME SW OTSEGO COUNTY AND NW CRAWFORD COUNTY. BANDING IS MAKING ITS EXPECTED SHIFT EAST...AND IS BEGINNING TO BECOME A LITTLE MORE DIFFUSE. EXPECT WE/VE GOT 2-3 MORE HOURS OF DECENT ACCUMS BEFORE THINGS WIND DOWN. ADVISORY CONTINUES TO LOOK GOOD AND WILL MAKE NO CHANGES TO THIS. UPDATE ISSUED AT 519 AM EDT MON APR 1 2013 CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP BY LATE MORNING. NO OTHER CHANGES ATTM. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 422 AM EDT MON APR 1 2013 HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES AS WELL. OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING THE SHORT TERM PORTION OF THE FORECAST. THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING COMMUTE. WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE COASTS. TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS WELL. SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS AFTERNOON. WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY NEAR THE LAKESHORES AND OVER EASTERN UPPER. TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID 20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE DAY. HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE. AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS. TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2 INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO COMPELLING REASON TO DEVIATE SIGNIFICANTLY. CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR... GENERALLY IN THE UPPER TEENS TO AROUND 20. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 422 AM EDT MON APR 1 2013 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. THE MOISTURE IN THE 850-700 MB LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON, THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE. THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON. TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW. WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY ALLOWING IT TO JUST TOUCH E UPPER BY 12Z. EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN. SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE PESSIMISTIC FORECAST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 708 AM EDT MON APR 1 2013 SUMMARY: STRONG LOW PRESSURE...DEPARTING INTO EASTERN CANADA WILL CAUSE STRONG NORTHWEST WINDS THROUGH THE UPCOMING TAF PERIOD...WITH OCCASIONAL LAKE EFFECT SNOW SHOWERS IMPACTING THE TAF SITES. RESTRICTIONS: LAKE EFFECT SNOW BANDS DOING A GOOD JOB AVOIDING THE TERMINALS EARLY THIS MORNING. PRIMARY BAND FROM CHARLEVOIX TO GAYLORD WILL START TO BREAK UP AS IT SHIFTS EAST...BUT WILL LIKELY BRING A PERIOD OF MVFR/IFR TO PLN FOR A TIME THIS MORNING. LAKE EFFECT SHSN WILL CONTINUE THIS AFTERNOON...BUT IN A MORE CELLULAR/SCATTERED FASHION...WHICH WILL LIKELY ALLOW TVC/MBL/APN TO REMAIN VFR WHILE PLN DEALS WITH OCCASIONAL MVFR VSBYS-CIGS /WITH PERHAPS VERY BRIEF IFR VSBYS/. SHSN ACTIVITY WILL CONTINUE TONIGHT...BUT WILL AVOID INCLUDING MVFR/IFR RESTRICTIONS IN THIS TAF PACKAGE AS THESE SHSN WILL BE SHORT-LIVED AND CONFIDENCE NOT HIGH ENOUGH ON LOCATION /ALTHOUGH BEST CHANCES WILL LIKELY CONTINUE TO BE AT PLN/ TO INCLUDE. WINDS: NORTHWEST WINDS WILL REACH 18G28KTS FOR THE DAY TODAY BEFORE DIMINISHING TO 10-15KTS TONIGHT. && .MARINE... ISSUED AT 422 AM EDT MON APR 1 2013 UPDATE AT 708 AM...DROPPED GALE WARNINGS FOR ALL AREAS SAVE WHITEFISH BAY AND THE COAST OF NORTHERN LAKE HURON. HIGH END SMALL CRAFTS SHOULD SUFFICE THROUGH TODAY AND WILL NEED EXTENDING BEYOND TONIGHT IN SUBSEQUENT UPDATES. SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY MIDWEEK WITH QUIETER CONDITIONS EXPECTED. HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS. BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF NEXT APPROACHING SYSTEM. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR MIZ019-021-022- 028. LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345-346- 349. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ347-348. LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341- 342-344>346. LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ322. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321. && $$ UPDATE...SR SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...ARNOTT MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT MON APR 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 440 AM EDT MON APR 1 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF CENTERED FM HUDSON BAY INTO THE GRT LKS DOWNSTREAM OF UPR RDG OVER WRN CANADA. 00Z H5/H85 TEMPS ARE AS LO AS -42C/-20C AT THE CORE OF THE COLDEST AIR AT YPL. CYC NNW FLOW ON THE WRN FLANK OF LO PRES MOVING SLOWLY E INTO QUEBEC IS DRAWING THIS VERY COLD AIR SWD INTO THE UPR LKS OVER THE RELATIVELY WARM WATERS OF LAKE SUP...WITH THE RESULT NMRS LES BANDS AS SHOWN ON MQT RADAR. WELL DEFINED AXIS OF COLDER CLD TOPS AS SHOWN ON IR STLT IMAGERY IS PRESENT OVER THE E HALF OF THE LK AND ASSOCIATED WITH FAIRLY SHARP H7-3 QVECTOR CNVGC. THIS AXIS OF DEEPER MSTR HAS CAUSED SOME ENHANCEMENT TO THE SHSN. THE HEAVIEST BAND IS STREAMING INTO CENTRAL ALGER COUNTY/SCHOOLCRAFT COUTY...WITH SOME RETURNS AOA 30 DBZ AT 06Z. SN UNDER THIS BAND IS LIKELY FALLING AT THE RATE OF AT LEAST AN INCH/HR GIVEN FAVORABLE LOCATION OF UVV MAX WITHIN DGZ AS SHOWN BY PROFILE FM LOCAL HI RES MODEL. SINCE THE COLDER CLD TOPS ARE TENDING TO DRIFT TO THE E AND DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB IS PRESSING TO THE E... DROPPING THE SFC DEWPT TO NEAR 7F AT IWD AT 06Z...THE INTENSITY OF THE LES W OF MQT HAS TENDED TO DIMINISH OVER TIME PER RADAR TRENDS EVEN THOUGH IR STLT IMAGERY INDICATES SOME LES BANDS OVER THE W HALF OF THE LK THAT HAVE FORMED IN THE PRESENCE OF NOCTURNAL COOLING THAT IS SO IMPORTANT TO ACHIEVE BETTER LES BAND STRUCTURE THIS TIME OF YEAR. NW WINDS ARE STILL GUSTING AS HI AS 40 KTS AT STANNARD ROCK AS OF 06Z...BUT PASSAGE OF PRES RISE CENTER TRAILING THE SFC LO INTO ONTARIO E OF LK SUP HAS CAUSED A SLOW DIMINISHING TREND TO THE WINDS. MAIN FCST CONCERNS THIS PACKAGE ARE LES TRENDS/GOIND HEADLINES. TODAY...MODELS INDICATE UPR TROF AXIS WL DRIFT SLOWLY TO THE E. AREA OF DEEP LYR QVECTOR CNVGC ENHANCING COMMA HEAD/COLDER CLD TOPS NOW OVER THE E HALF OF LK SUP IS PROGGED TO DRIFT INTO ONTARIO IN THE 09Z-12Z TIME FRAME. IN CONCERT WITH THE ARRIVAL OF SOME DRYING FM THE W...LES INTENSITY/COVERAGE SHUD DIMINISH BY SUNRISE. BUT GIVEN PERSISTENCE OF SGNFT BAND OVER CENTRAL ALGER COUNTY INTO NRN SCHOOLCRAFT COUNTY IN PERSISTENT NNW FLOW THRU THE EARLY MRNG HRS...FVRBL SN/WATER RATIOS UNDER COLDEST H85 TEMPS...AND HIER RES MODEL FCSTS THAT SHOWING FAIRLY HI QPF THRU 18Z WITH DEEPER MSTR PERSISTING LONGEST IN THAT AREA CLOSER TO DEPARTING LO...OPTED TO UPGRADE GOING ADVY FOR THOSE ZONES TO AN LES WARNING. OTRW...RISING H5 HGTS/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE PRESENCE OF DIURNAL HEATING THAT TENDS TO DISRUPT THE LES PROCESS IN EARLY SPRING SHOULD CAUSE THE LES BANDS TO WEAKEN AND TRANSITION TO A MORE BLOTCHY APPEARANCE. SLOWLY BACKING FLOW TOWARD MORE WNW BY THE LATE IN THE DAY WL ALSO CAUSE AREA OF HEAVIER SHSN TO SHIFT. ADDITIONAL SN AMOUNTS OVER THE W WL BE LIGHT WITH LLVL DRY AIR HAVING A MORE SGNFT IMPACT THERE AND MODELS HINTING TOWARD A TRANSITION TO LLVL ACYC FLOW IN THE AFTN. TONIGHT...STEADILY RISING HGTS/DEEP LYR QVECTOR CNVGC THAT DROPS FCST INVRN BASE TOWARD 5-6K FT OVER EVEN THE E SUG LES INTENSITY WL BE SOMEWHAT DIMINISHED EVEN THOUGH PERSISTENT NW FLOW/H85 TEMPS IN THE -16 TO -17C RANGE WL ALLOW FOR CONTINUED WDSPRD LES...ESPECIALLY AFTER MID EVNG WHEN IMPACTS OF DAYTIME HEATING WOULD TEND TO SUBSIDE. WITH INVRN BASE OVER THE W FALLING TO ARND 4K FT OVER THE W...SHSN INTENSITY IN THIS AREA WL BE WEAKER WITH SHORTER FETCH/LESS MODERATION OF UPSTREAM AIRMASS. BUT STILL WENT WITH LIKELY POPS GIVEN FVRBL NW FLOW/OVERWATER INSTABILITY/NOCTURNAL COOLING THAT WL ALLOW LES BANDS TO REDEVELOP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 440 AM EDT MON APR 1 2013 DESPITE ADEQUATE DELTA TS PERSISTING INTO TUESDAY FOR LAKE EFFECT...SFC-H85 FLOW WILL BECOME INCREASINGLY ANTICYCLONIC THROUGH THE DAY. IN ADDITION...INVERSION HEIGHTS BEGIN TO FALL OFF SIGNIFICANTLY BELOW 5KFT. THUS...EXPECT OVERALL COVERAGE AND INTENSITY OF LAKE EFFECT TO BE ON THE WANE AS THE DAY PROGRESSES. TEMPERATURES WILL REMAIN WELL BELOW NORMAL WITH A SIGNIFICANT AMOUNT OF CLOUDINESS DOWNWIND OF LAKE SUPERIOR. LAKE CLOUDS AND EVEN A FEW FLURRIES WILL PERSIST INTO THE MORNING WEDNESDAY OVER THE EAST. AS SURFACE RIDGE AXIS MOVES OVERHEAD THROUGH THE DAY EXPECT SKIES TO BECOME MOSTLY SUNNY AREA WIDE. TEMPERATURES SHOULD REBOUND BACK ABOVE FREEZING AND EVEN APPROACH 40 ACROSS THE WEST WITH WARM ADVECTION INCREASING DURING THE AFTERNOON AND MORE SUNSHINE. MODELS COMING INTO BETTER AGREEMENT WITH THE TIMING OF THE NEXT SHORTWAVE AND SFC TROUGH EXPECTED TO MOVE ACROSS THE AREA WED NIGHT/THU. THE TREND HAS BEEN TOWARD QUICKER MOVEMENT WITH THE TROUGH. SYSTEM IS FAIRLY MOISTURE STARVED...SO DESPITE PRECIP TYPE BEING A CHALLENGE BETWEEN RAIN AND SNOW...AMOUNTS WILL BE LIGHT ENOUGH TO BE PRETTY INSIGNIFICANT. COLD ADVECTION BEHIND THE TROUGH SHOULD PUSH 85H TEMPS BACK DOWN TO THE -10 TO -14C RANGE BY FRIDAY. PROBABLY NOT QUITE COLD ENOUGH FOR LAKE EFFECT THIS TIME AROUND...BUT COLDER AIR WILL KEEP DAYTIME TEMPS BELOW AVERAGE ONLY IN THE 30S. FORECAST FOR NEXT WEEKEND STILL PRETTY CHALLENGING...BUT MODELS SHOWING SOME SIGNS THAT THEY ARE TRYING TO CONVERGE ON A MORE PROBABLE OUTCOME. SHORTWAVE ENERGY AND ASSOCIATED SURFACE LOW MOVING OUT OF THE PLAINS LOOKING LIKE THEY MAY NOW TRACK THROUGH THE LOWER LAKES WHICH WOULD STILL RESULT IN SOME LIGHT SNOWFALL ACROSS SOUTHERN AREAS SATURDAY INTO SUNDAY BUT SPARE THE AREA FROM A MORE SIGNIFICANT STORM. IT IS STILL SOMETHING TO KEEP AN EYE ON AS WE HEAD THROUGH THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 726 AM EDT MON APR 1 2013 ALTHOUGH NW FLOW OF COLD AIR FLOWING ACRS LK SUP MAY CAUSE MVFR CONDITIONS AT TIMES AT IWD/CMX WITH UPSLOPE WIND COMPONENT...EXPECT VFR CONDITIONS TO PREDOMINATE AT THESE SITES GIVEN VERY DRY NATURE OF THE LLVLS UPSTREAM AS SHOWN ON THE 00Z INL/YQD RAOBS. WITH A DOWNSLOPE WIND COMPONENT AND THIS DRYNESS...SAW HAS THE BEST SHOT TO REMAIN VFR FOR THE ENTIRE TIME. GUSTY NW WINDS WL LINGER... ESPECIALLY AT THE MORE EXPOSED CMX LOCATION. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 440 AM EDT MON APR 1 2013 AS LO PRES OVER SE CANADA CONTINUES TO THE E AND THE PRES GRADIENT WEAKENS...EXPECT NW WINDS TO SLOWLY DIMINISH AND BELOW GALE FORCE OVER THE CENTRAL BY MID MORNING...SO HASTENED THE ENDING OF THE GALE WARNINGS FOR THIS AREA. ALTHOUG NW GALES TO 35 KTS WILL CONTINUE LONGER OVER THE E INTO THIS EVENING...ENDED THE GALES FOR THAT AREA EARLIER AS WELL. WINDS/WAVES WILL BE SUFFICIENT TO MAINTAIN FREEZING SPRAY OVER AT LEAST THE E HALF THRU TONIGHT. WINDS WILL REMAIN PRETTY GUSTY UP TO 30 KNOTS OVER THE EASTERN LAKE THROUGH THE DAY ON TUESDAY...BUT AS SURFACE RIDGE AXIS PUSHES IN FROM THE WEST PRESSURE GRADIENT WILL RELAX AND WINDS WILL DIMINISH DURING THE EVENING. UNTIL THAT TIME...FREEZING SPRAY SHOULD CONTINUE ACROSS THE EASTERN LAKE. AFTER A BRIEF RESPITE ON WEDNESDAY...SOUTHWESTERLY WINDS UP TO 25 KNOTS AHEAD OF THE NEXT TROUGH CROSSING THE LAKE WILL INCREASE WEDNESDAY NIGHT INTO EARLY THURSDAY BEFORE SHIFTING TO THE NORTHWEST DURING THE DAY THURSDAY INTO THURSDAY NIGHT. WINDS FOR FRIDAY INTO NEXT WEEKEND SHOULD BE BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007. LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-085. LAKE SUPERIOR... GALE WARNING UNTIL 2 AM EDT TUESDAY FOR LSZ250-251-266-267. GALE WARNING UNTIL NOON EDT TODAY FOR LSZ265. GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ244-245-264. GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...MZ AVIATION...KC MARINE...KC/MZ
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
716 AM EDT MON APR 1 2013 .SYNOPSIS... ISSUED AT 422 AM EDT MON APR 1 2013 A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER MICHIGAN. && .UPDATE... ISSUED AT 708 AM EDT MON APR 1 2013 CHANGES THIS HOUR: ADDITIONAL /UPWARD/ ADJUSTMENTS TO SNOWFALL AS A BAND OF NEARLY 5 INCHES HAS OCCURRED OVER EXTREME SW OTSEGO COUNTY AND NW CRAWFORD COUNTY. BANDING IS MAKING ITS EXPECTED SHIFT EAST...AND IS BEGINNING TO BECOME A LITTLE MORE DIFFUSE. EXPECT WE/VE GOT 2-3 MORE HOURS OF DECENT ACCUMS BEFORE THINGS WIND DOWN. ADVISORY CONTINUES TO LOOK GOOD AND WILL MAKE NO CHANGES TO THIS. UPDATE ISSUED AT 519 AM EDT MON APR 1 2013 CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP BY LATE MORNING. NO OTHER CHANGES ATTM. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 422 AM EDT MON APR 1 2013 HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES AS WELL. OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING THE SHORT TERM PORTION OF THE FORECAST. THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING COMMUTE. WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE COASTS. TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS WELL. SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS AFTERNOON. WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY NEAR THE LAKESHORES AND OVER EASTERN UPPER. TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID 20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE DAY. HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE. AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS. TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2 INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO COMPELLING REASON TO DEVIATE SIGNIFICANTLY. CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR... GENERALLY IN THE UPPER TEENS TO AROUND 20. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 422 AM EDT MON APR 1 2013 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. THE MOISTURE IN THE 850-700 MB LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON, THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE. THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON. TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW. WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY ALLOWING IT TO JUST TOUCH E UPPER BY 12Z. EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN. SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE PESSIMISTIC FORECAST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 708 AM EDT MON APR 1 2013 SUMMARY: STRONG LOW PRESSURE...DEPARTING INTO EASTERN CANADA WILL CAUSE STRONG NORTHWEST WINDS THROUGH THE UPCOMING TAF PERIOD...WITH OCCASIONAL LAKE EFFECT SNOW SHOWERS IMPACTING THE TAF SITES. RESTRICTIONS: LAKE EFFECT SNOW BANDS DOING A GOOD JOB AVOIDING THE TERMINALS EARLY THIS MORNING. PRIMARY BAND FROM CHARLEVOIX TO GAYLORD WILL START TO BREAK UP AS IT SHIFTS EAST...BUT WILL LIKELY BRING A PERIOD OF MVFR/IFR TO PLN FOR A TIME THIS MORNING. LAKE EFFECT SHSN WILL CONTINUE THIS AFTERNOON...BUT IN A MORE CELLULAR/SCATTERED FASHION...WHICH WILL LIKELY ALLOW TVC/MBL/APN TO REMAIN VFR WHILE PLN DEALS WITH OCCASIONAL MVFR VSBYS-CIGS /WITH PERHAPS VERY BRIEF IFR VSBYS/. SHSN ACTIVITY WILL CONTINUE TONIGHT...BUT WILL AVOID INCLUDING MVFR/IFR RESTRICTIONS IN THIS TAF PACKAGE AS THESE SHSN WILL BE SHORT-LIVED AND CONFIDENCE NOT HIGH ENOUGH ON LOCATION /ALTHOUGH BEST CHANCES WILL LIKELY CONTINUE TO BE AT PLN/ TO INCLUDE. WINDS: NORTHWEST WINDS WILL REACH 18G28KTS FOR THE DAY TODAY BEFORE DIMINISHING TO 10-15KTS TONIGHT. && .MARINE... ISSUED AT 422 AM EDT MON APR 1 2013 UPDATE AT 708 AM...DROPPED GALE WARNINGS FOR ALL AREAS SAVE WHITEFISH BAY AND THE COAST OF NORTHERN LAKE HURON. HIGH END SMALL CRAFTS SHOULD SUFFICE THROUGH TODAY AND WILL NEED EXTENDING BEYOND TONIGHT IN SUBSEQUENT UPDATES. SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY MIDWEEK WITH QUIETER CONDITIONS EXPECTED. HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS. BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF NEXT APPROACHING SYSTEM. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR MIZ019-021-022- 028. LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345-346- 349. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ347-348. LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341- 342-344>346. LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ322. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321. && $$ UPDATE...ARNOTT SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...ARNOTT MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1030 AM EDT MON APR 1 2013 .SYNOPSIS... A WEAK FRONT WILL MOVE THROUGH AND BRING SCATTERED RAIN SHOWERS THROUGH THIS AFTERNOON. A STRONGER FRONT WILL MOVE THROUGH TONIGHT USHERING IN COOL AIR FOR THE MID WEEK PERIOD. GULF OF MEXICO LOW PRESSURE WILL MOVE UP THE CAROLINA COAST FRIDAY BRINGING A SOAKING RAIN. NEXT WEEKEND SHOULD BE FAIR AND SEASONABLE. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM MONDAY...SEVERAL FEATURES WORKING TOGETHER TO BRING US SOME SHOWERS THIS MORNING...AND THESE WILL LINGER INTO THE EARLY AFTN BEFORE RAPID DRYING OCCURS LATER TODAY. PRECIP ONGOING AT THIS HOUR IS DRIVEN PRIMARILY BY A VORT MAX MOVING ACROSS SC. THIS WILL CONTINUE TO WORK EAST THROUGH THE AFTN...CONTINUING THE CHANCES FOR SHOWERS. BUFR PROFILES SUGGEST INCREASING INSTABILITY AHEAD OF THE UPPER FEATURE...ESPECIALLY ACROSS SOUTHERN ZONES WHICH WILL BE MORE DIRECTLY IMPACTED BY THE IMPULSE MOVING OVERHEAD. HAVE INTRODUCED ISO -TRW FOR THE EXTREME SOUTHERN ZONES SINCE THERE APPEARS TO BE ENOUGH LIFT AND INSTABILITY FOR AN ISOLATED LIGHTNING STRIKE THROUGH THE AFTN...BUT NOTHING WIDESPREAD...AND ANY CHC FOR THUNDER WILL END QUICKLY AS VORT SKIRTS OFFSHORE. WEAK COLD FRONT...AND I DON`T LIKE THE TERM COLD FRONT DUE TO LACK OF ANY TEMP GRADIENT...WILL DROP SOUTH THIS AFTN BEHIND THE DEPARTING SHORTWAVE. THE COMBINATION OF SOME SUBSIDENCE BEHIND THIS SHORTWAVE AND DRYING BEHIND THE COLD FRONT (TROUGH) WILL BRING AN END TO THE SHOWERS EARLY THIS AFTN...WITH RAPID DRYING OCCURRING IN THE COLUMN THEREAFTER. THIS DRYING WILL ALLOW FOR SOME SUN TO PEEK THROUGH THIS AFTN/EVE...AND HIGH TEMPS WILL STILL REACH TO 70 OR HIGHER EVEN BEHIND THE "COLD FRONT" THANKS TO THE APRIL INSOLATION. A MORE SIGNIFICANT COLD FRONT...THIS ONE ACCOMPANIED BY REAL CAA...WILL DROP SOUTH TONIGHT AND TEMPS WILL PLUMMET BEHIND IT. THE EXACT TIMING IS STILL IN QUESTION...BUT IT APPEARS THIS FRONT WILL DROP THROUGH THE CWA AFTER MIDNIGHT AND HELP MINS FALL TO SEASONABLE LEVELS...LOW 40S NORTH TO UPPER 40S SOUTH...AND HAVE LEANED ON THE SLIGHTLY COOLER MAV NUMBERS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...DEEP UPPER CUTOFF NORTH OF NEW ENGLAND STATES ON TUESDAY HELPING TO PUSH ARCTIC COLD FRONT AND ITS ASSOC MOISTURE OFF TO THE SOUTH OF THE AREA. THE UPPER LOW WILL BE LIFTING OUT TO THE NORTH A BIT HOWEVER AND THIS WILL TEMPER THE STRENGTH OF THE COLD AIR ADVECTION INTO THE CAROLINAS. GUIDANCE HAS COME UP A FEW DEGREES PAST SEVERAL RUNS BUT HAVE OPTED TO REMAIN A FEW DEGREES BELOW AS THE VERY SHALLOW NATURE OF THE COLD AIR MAY BUST THE NUMBERS A BIT. CURRENT FORECAST CAPS HIGHS AT ABOUT 10F BELOW CLIMO. THE SAME DEVIATION FROM NORMAL IS EXPECTED TUESDAY NIGHT WITH LOWS UPPER 30S/NR 40. ATTENTION TURNS TO SOUTHERN BRANCH AS WE HEAD INTO WEDNESDAY. THE NORTHERN STREAM UPPER LOW CONTINUES ITS SLOW LIFTING/PROGRESSING ENERGY MOVING ACROSS TX WILL BEGIN CYCLOGENESIS IN THE WESTERN GULF. WRF READILY SPREADS CLOUD COVER AND INCREASING RAIN CHANCES INTO THE REGION LATE WEDNESDAY AND THEN VERY MUCH SO WEDNESDAY NIGHT. GIVEN THE MID LEVEL CONFLUENCE ALLOWING THE HIGH TO REALLY HANG ON AND THAT DEWPOINTS WILL INITIALIZE PRETTY LOW FEEL THAT THIS IS TOO FAST. END OF PERIOD A COMPROMISE BETWEEN GFS AND WRF. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...VERY RAINY PERIOD TO START THE LONG TERM AS SOUTHERN BRANCH FEATURE TAPS COPIOUS GOMEX MOISTURE AND FLINGS IT UP ACROSS THE CAROLINAS. THERE ARE SOME TIMING DIFFERENCES BETWEEN VARIOUS GUIDANCE BUT THE BULK OF THE RAINFALL APPEARS TO BE SLATED FOR THURSDAY NIGHT INTO FRIDAY MORNING. THEREAFTER DEPENDING ON THE TRACK OF THE LOW A DRY SLOT MAY WORK UP THE COAST. TEMPS ALSO VERY MUCH HINGE ON THE TRACK OF THE STORM AS EASTERN COUNTIES APPEAR LIKELY TO SECURELY WARM SECTOR WHERE INLAND ZONES MAY STRUGGLE A BIT. TOUGH TO SAY HOW QUICK THE DRYING IS LATER FRIDAY DUE TO THE LAGGING OF THE UPPER TROUGH INCLUDING WRAPAROUND RAIN POTENTIAL THOUGH SMALL. HIGH BUILDS IN BEHIND THIS SYSTEM FOR THE WEEKEND AMIDST LOW AMPLITUDE MID LVL FLOW BRINGING A FAIR AMOUNT OF SUN AND CLIMO TEMPS...EVEN PERHAPS A WARMING TREND. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... AS OF 12Z...MOST OF THE RAIN IS OVER THE WESTERN TERMINALS AT THIS TIME. TIME HEIGHTS AND HRRR MODEL ARE IN REASONABLE AGREEMENT IN MOVING THE PRECIP TOWARD THE COAST WITH A FRONT THAT BASICALLY WASHES OUT AFTER IT EXITS THE COAST THIS AFTERNOON. LOOK FOR CONDITIONS TO BOUNCE FROM VFR TO MVFR IN THE PRECIP. ALL AREAS WILL BECOME VFR BY EARLY AFTERNOON AS THE BULK OF THE DEEP MOISTURE SHIFTS TO THE SOUTHEAST. A STRONGER FRONT MOVES IN TONIGHT. NO WEATHER ASSOCIATED WITH IT OTHER THAN A WIND SHIFT TO THE NORTH AND A VFR STRATA CU CEILING. EXTENDED OUTLOOK...VFR TUESDAY AND WEDNESDAY. SHOWERS AND SUB-VFR CONDITIONS LIKELY THURSDAY AND FRIDAY AS LOW PRESSURE MOVES UP THE ATLANTIC COAST. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM MONDAY...BUOY 41008 AND 41013 HAVE FINALLY SHOWN THE RAPID DROP OFF WE WERE EXPECTING THIS MORNING...AND DROPPED THE SCA FOR THE NC WATERS AS NEEDED. A SERIES OF COLD FRONTS...THE FIRST QUITE WEAK...WILL DROP SOUTH ACROSS THE WATERS TODAY. THIS FIRST ONE CROSSES LATE THIS AFTN...BRINGING A SLIGHT WIND SHIFT TO W/NW AND AN END TO SHOWERS/TSTMS. THE STRONGER FRONT CROSSES LATE TONIGHT...AND WILL BE ACCOMPANIED BY A STRONG BUT SHORT-LIVED SURGE OF N/NE WINDS APPROACHING 20 KTS. WHILE SEAS MAY TICK UPWARD WITH THIS SURGE...AFTER BEING 2-4 FT MUCH OF THE DAY...DO NOT ANTICIPATE THE NEED FOR ANY CAUTIONARY STATEMENTS OR HEADLINES ATTM. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...MAIN AREA OF HIGH PRESSURE BUILDING IN FROM THE NORTH AND WEST IN A FAIRLY RESTRAINED MANNER ON TUESDAY KEEPING THE CENTER UP IN THE GREAT LAKES. A SMALLER AND POORLY DEFINED CENTER SLIPS INTO THE CAROLINAS HOWEVER KEEPING GRADIENT VERY LIGHT LEADING AND TAME WINDS OUT OF THE N/NE. SEAS BEGIN THE PERIOD STIRRED UP FROM THE NEAR TERM BUT WILL QUICKLY ABATE. THE PARENT AIRMASS DRAWS A LITTLE CLOSER WEDNESDAY PICKING UP AND SLIGHTLY VEERING THE WINDS. AS THE HIGH SETTLES ACRS VA BY THE END OF THE PERIOD AND LOW PRESSURE MARCHES EAST ACROSS THE GULF COAST THERE SHOULD BE AN ADDITIONAL VEER AND SMALL INCREASE IN WINDS. THE SPEED AT WHICH THIS HAPPENS IS A LITTLE UNCERTAIN. .LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...MODERATELY STRONG SOUTHERN BRANCH FEATURE COMING ACROSS THE GULF OF MEXICO ON THURSDAY WHILE WEST ATLANTIC HIGH PRESSURE PROGRESSES EASTWARD BUT AT A SLOWER SPEED. THIS WILL INCREASE THE GRADIENT UP AND DOWN THE SOUTHEAST COAST AND A SMALL CRAFT ADVISORY WILL BE NEEDED. AS THE STORM SYSTEM TURNS TO THE NE AND MOVES RIGHT UP THE CAROLINA COAST ON AN INLAND TRACK THE STRONG SW FLOW WILL BE MAINTAINED IF NOT STRENGTHENED. EXPECT A FURTHER BUILDING OF SEAS FROM ADDED FETCH DURATION IF NOTHING ELSE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...TRA/JDW NEAR TERM...JDW SHORT TERM...MBB LONG TERM...MBB AVIATION...TRA/BJR MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
651 AM EDT MON APR 1 2013 .SYNOPSIS... A WEAK FRONT WILL MOVE THROUGH AND BRING WIDESPREAD RAIN THIS MORNING. A STRONGER FRONT WILL MOVE THROUGH TONIGHT USHERING IN COOL AIR FOR THE MID WEEK PERIOD. GULF OF MEXICO LOW PRESSURE WILL MOVE UP THE CAROLINA COAST FRIDAY BRINGING A SOAKING RAIN. NEXT WEEKEND SHOULD BE FAIR AND SEASONABLE. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...LINEAR EXTRAPOLATION OF THE BACK EDGE OF THE RADAR ECHOES ACROSS EASTERN GEORGIA PLACES IT NEAR FLORENCE AROUND 15Z/10:00 AM EDT...AND IN WILMINGTON AROUND 1730Z/1:30 PM EDT. THAT IS LIKELY A LITTLE SLOW GIVEN HOW QUICKLY THE UPPER LEVEL FEATURE AND ITS SUBSEQUENT MID-LEVEL DRYING SHOULD ADVECT EAST TOWARD THE COAST...SO I FEEL COMFORTABLE WITH A FORECAST STILL CALLING FOR THE BULK OF THE PRECIP TO BE OFFSHORE BY NOON. 06Z MODELS MADE NO SIGNIFICANT CHANGES WITH AFTERNOON TEMPERATURES EITHER. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... A COLD FRONT LIES ACROSS NORTH CAROLINA FROM NEAR CHARLOTTE NORTHEAST THROUGH FAYETTEVILLE AND GREENVILLE... SEPARATING SUBTROPICAL AIR TO THE SOUTH FROM A HEAVILY MODIFIED ARCTIC AIRMASS TO THE NORTH. THIS BOUNDARY WILL SAG SOUTH DURING THE DAY...CLEARING THE COASTLINE BY MID TO LATE AFTERNOON. IN THE UPPER LEVELS A 500 MB DISTURBANCE WILL SWEEP OFFSHORE DURING THE LATE MORNING HOURS...TAKING MOST OF THE DEEP-LAYER MOISTURE WITH IT. RADAR COMPOSITES SHOW A CONCENTRATED STREAK OF SHOWERS AND EMBEDDED THUNDERSTORMS EXTENDING FROM CAPE FEAR WESTWARD ACROSS SC TO NEAR ATLANTA. MODEL SOUNDINGS SHOW SOMETHING WE HAVEN`T SEEN A LOT OF THIS YEAR: CONVECTIVE INSTABILITY THROUGH A DEEP LAYER OF THE ATMOSPHERE. CAPE VALUES ARE NOT AND WILL NOT GET VERY HIGH...ONLY A COUPLE HUNDRED J/KG FOR ANY INITIAL PARCEL LEVEL...BUT GIVEN THE SYNOPTIC LIFT OCCURRING IN ADVANCE OF THE SHORTWAVE UPRIGHT CONVECTION HAS DEVELOPED AND MAY CONTINUE THROUGH THE MORNING. RAINFALL AMOUNTS COULD APPROACH HALF AN INCH ACROSS FLORENCE... MARION AND WHITEVILLE THIS MORNING. ONCE THE SHORTWAVE CLEARS THE COAST THERE IS VERY LITTLE SUPPORT REMAINING FOR SHOWER ACTIVITY. CLOUDS SHOULD ALSO DIMINISH... ALTHOUGH MODELS CONTINUE TO PAINT BOTH CIRRUS AND SOME BOUNDARY- LAYER DRIVEN CUMULUS INTO LATE AFTERNOON. SINCE THERE IS LITTLE REAL COLD ADVECTION BEHIND THIS FIRST COLD FRONT HIGHS SHOULD RISE INTO THE LOWER TO MID 70S AWAY FROM THE BEACHES...ACTUALLY A FEW DEGREES ABOVE NORMAL. TONIGHT A SECOND MUCH STRONGER COLD FRONT WILL DIVE IN FROM THE NORTH SHORTLY AFTER MIDNIGHT...ACCOMPANIED BY A SHIFT TO NORTH WINDS AND A MORE IMPRESSIVE SHOT OF COLD ADVECTION. TEMPERATURES WILL FALL IN EARNEST LATE AND LOWS SHOULD REACH THE 40S EVERYWHERE BY DAYBREAK TUESDAY. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...DEEP UPPER CUTOFF NORTH OF NEW ENGLAND STATES ON TUESDAY HELPING TO PUSH ARCTIC COLD FRONT AND ITS ASSOC MOISTURE OFF TO THE SOUTH OF THE AREA. THE UPPER LOW WILL BE LIFTING OUT TO THE NORTH A BIT HOWEVER AND THIS WILL TEMPER THE STRENGTH OF THE COLD AIR ADVECTION INTO THE CAROLINAS. GUIDANCE HAS COME UP A FEW DEGREES PAST SEVERAL RUNS BUT HAVE OPTED TO REMAIN A FEW DEGREES BELOW AS THE VERY SHALLOW NATURE OF THE COLD AIR MAY BUST THE NUMBERS A BIT. CURRENT FORECAST CAPS HIGHS AT ABOUT 10F BELOW CLIMO. THE SAME DEVIATION FROM NORMAL IS EXPECTED TUESDAY NIGHT WITH LOWS UPPER 30S/NR 40. ATTENTION TURNS TO SOUTHERN BRANCH AS WE HEAD INTO WEDNESDAY. THE NORTHERN STREAM UPPER LOW CONTINUES ITS SLOW LIFTING/PROGRESSING ENERGY MOVING ACROSS TX WILL BEGIN CYCLOGENESIS IN THE WESTERN GULF. WRF READILY SPREADS CLOUD COVER AND INCREASING RAIN CHANCES INTO THE REGION LATE WEDNESDAY AND THEN VERY MUCH SO WEDNESDAY NIGHT. GIVEN THE MID LEVEL CONFLUENCE ALLOWING THE HIGH TO REALLY HANG ON AND THAT DEWPOINTS WILL INITIALIZE PRETTY LOW FEEL THAT THIS IS TOO FAST. END OF PERIOD A COMPROMISE BETWEEN GFS AND WRF. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...VERY RAINY PERIOD TO START THE LONG TERM AS SOUTHERN BRANCH FEATURE TAPS COPIOUS GOMEX MOISTURE AND FLINGS IT UP ACROSS THE CAROLINAS. THERE ARE SOME TIMING DIFFERENCES BETWEEN VARIOUS GUIDANCE BUT THE BULK OF THE RAINFALL APPEARS TO BE SLATED FOR THURSDAY NIGHT INTO FRIDAY MORNING. THEREAFTER DEPENDING ON THE TRACK OF THE LOW A DRY SLOT MAY WORK UP THE COAST. TEMPS ALSO VERY MUCH HINGE ON THE TRACK OF THE STORM AS EASTERN COUNTIES APPEAR LIKELY TO SECURELY WARM SECTOR WHERE INLAND ZONES MAY STRUGGLE A BIT. TOUGH TO SAY HOW QUICK THE DRYING IS LATER FRIDAY DUE TO THE LAGGING OF THE UPPER TROUGH INCLUDING WRAPAROUND RAIN POTENTIAL THOUGH SMALL. HIGH BUILDS IN BEHIND THIS SYSTEM FOR THE WEEKEND AMIDST LOW AMPLITUDE MID LVL FLOW BRINGING A FAIR AMOUNT OF SUN AND CLIMO TEMPS...EVEN PERHAPS A WARMING TREND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 12Z...MOST OF THE RAIN IS OVER THE WESTERN TERMINALS AT THIS TIME. TIME HEIGHTS AND HRRR MODEL ARE IN REASONABLE AGREEMENT IN MOVING THE PRECIP TOWARD THE COAST WITH A FRONT THAT BASICALLY WASHES OUT AFTER IT EXITS THE COAST THIS AFTERNOON. LOOK FOR CONDITIONS TO BOUNCE FROM VFR TO MVFR IN THE PRECIP. ALL AREAS WILL BECOME VFR BY EARLY AFTERNOON AS THE BULK OF THE DEEP MOISTURE SHIFTS TO THE SOUTHEAST. A STRONGER FRONT MOVES IN TONIGHT. NO WEATHER ASSOCIATED WITH IT OTHER THAN A WIND SHIFT TO THE NORTH AND A VFR STRATA CU CEILING. EXTENDED OUTLOOK...VFR TUESDAY AND WEDNESDAY. SHOWERS AND SUB-VFR CONDITIONS LIKELY THURSDAY AND FRIDAY AS LOW PRESSURE MOVES UP THE ATLANTIC COAST. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...SEAS ARE FALLING VERY SLOWLY...BUT BASED ON 6 A.M. BUOY OBS IN THE CAPE FEAR VICINITY THE ADVISORY WILL NEED TO REMAIN POSTED THROUGH AT LEAST 9 A.M. NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... A COLD FRONT ACROSS INTERIOR NORTH CAROLINA WILL DROP SOUTHWARD SLOWLY DURING THE DAY...REACHING THE NORTH AND SOUTH CAROLINA COASTAL WATERS BY LATE AFTERNOON. WINDS WILL GRADUALLY VEER FROM SOUTHWEST TO WEST IN THE VICINITY OF THIS RATHER WEAK FRONT. SHOWER AND THUNDERSTORM ACTIVITY WILL OCCUR THIS MORNING MAINLY NORTH OF MYRTLE BEACH...WITH SHOWERS BECOMING VERY ISOLATED IF NOT TOTALLY ABSENT THIS AFTERNOON. A SECOND BUT MUCH STRONGER COLD FRONT WILL ARRIVE FROM THE NORTH AFTER MIDNIGHT TONIGHT...ACCOMPANIED BY A SHIFT TO NORTH WINDS WITH AN INCREASE IN SPEEDS TO 15-20 KNOTS. AT THIS TIME IT DOESN`T APPEAR SMALL CRAFT ADVISORIES WILL BE NEEDED...BUT CONDITIONS WILL CERTAINLY DETERIORATE LATE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...MAIN AREA OF HIGH PRESSURE BUILDING IN FROM THE NORTH AND WEST IN A FAIRLY RESTRAINED MANNER ON TUESDAY KEEPING THE CENTER UP IN THE GREAT LAKES. A SMALLER AND POORLY DEFINED CENTER SLIPS INTO THE CAROLINAS HOWEVER KEEPING GRADIENT VERY LIGHT LEADING AND TAME WINDS OUT OF THE N/NE. SEAS BEGIN THE PERIOD STIRRED UP FROM THE NEAR TERM BUT WILL QUICKLY ABATE. THE PARENT AIRMASS DRAWS A LITTLE CLOSER WEDNESDAY PICKING UP AND SLIGHTLY VEERING THE WINDS. AS THE HIGH SETTLES ACRS VA BY THE END OF THE PERIOD AND LOW PRESSURE MARCHES EAST ACROSS THE GULF COAST THERE SHOULD BE AN ADDITIONAL VEER AND SMALL INCREASE IN WINDS. THE SPEED AT WHICH THIS HAPPENS IS A LITTLE UNCERTAIN. .LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...MODERATELY STRONG SOUTHERN BRANCH FEATURE COMING ACROSS THE GULF OF MEXICO ON THURSDAY WHILE WEST ATLANTIC HIGH PRESSURE PROGRESSES EASTWARD BUT AT A SLOWER SPEED. THIS WILL INCREASE THE GRADIENT UP AND DOWN THE SOUTHEAST COAST AND A SMALL CRAFT ADVISORY WILL BE NEEDED. AS THE STORM SYSTEM TURNS TO THE NE AND MOVES RIGHT UP THE CAROLINA COAST ON AN INLAND TRACK THE STRONG SW FLOW WILL BE MAINTAINED IF NOT STRENGTHENED. EXPECT A FURTHER BUILDING OF SEAS FROM ADDED FETCH DURATION IF NOTHING ELSE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT THIS MORNING FOR AMZ250- 252. && $$ SYNOPSIS...TRA NEAR TERM...MBB SHORT TERM...MBB LONG TERM...MBB AVIATION...43
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
541 AM MDT MON APR 1 2013 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT ISSUED AT 240 AM MDT MON APR 1 2013 ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME. THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S. RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR SOME PASSING CIRRUS. TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH. .LONG TERM...WEDNESDAY THROUGH SUNDAY ISSUED AT 240 AM MDT MON APR 1 2013 UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 540 AM MDT MON APR 1 2013 MVFR CIGS WILL PERSIST ACROSS THE WESTERN SOUTH DAKOTA PLAINS THROUGH THE MORNING HOURS BEFORE LIFTING AND SHIFTING EAST BY 18Z. VFR CONDITIONS ARE THEN EXPECTED THROUGH TUESDAY MORNING. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...JC LONG TERM...15 AVIATION...15
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1126 AM MDT MON APR 1 2013 .UPDATE... ISSUED AT 1121 AM MDT MON APR 1 2013 PLAN TO DECREASE POPS SIGNIFICANTLY BETWEEN NOW AND MIDDAY TOMORROW ACROSS MANY PARTS OF THE REGION. DRY SLOT WILL SIGNIFICANTLY DECREASE PRECIP CHANCES BETWEEN NOW AND THEN. BEST CHANCES OF POPS DURING THE NEXT 24H WILL BE OVER FAR E PLAINS AND C MTN REGIONS. STILL EXPECT LOW CLOUDS TO INVADE ALL OF THE PLAINS LATER THIS EVENING. UPDATE WILL BE ISSUED AROUND 1 PM. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM MDT MON APR 1 2013 A SHORTWAVE TROF IS WRAPPING AROUND AN UPR LOW THAT IS OVR THE WRN STATES...AND IS BRINGING CLOUDS AND SOME PCPN TO PORTIONS OF WRN CO...SOME OF WHICH WL AFFECT THE CONTDVD THIS MORNING. ALSO THIS MORNING A FRONT IS CONTINUING TO MOVE SOUTHWARD THROUGH THE SERN PLAINS AS OF 3AM IT HAD MOVED SOUTH OF THE ARKANSAS RIVER VALLEY. HAVE SEEN SOME STRATUS DEVELOP BEHIND THIS FRONT IN NE AND PORTIONS OF NWRN KS. THE HRRR AND NAM12 SHOW LOW LEVEL RH VALUES/STRATUS BACKING INTO THE FAR SERN PLAINS A LITTLE LATER THIS MORNING...AND MAYBE BACKING INTO THE FAR ERN PORTIONS OF EL PASO COUNTY. THE NAM AND THE HRRR KEEP THE FAR SERN PLAINS DRY THRU THE MORNING HOURS...WHILE THE GFS PRINTS OUT SOME LIGHT QPF ASSOCIATED WITH THE STRATUS. DO NOT FEEL THAT MEASURABLE PCPN WL OCCUR SO WL KEEP THE FORECAST DRY OUT EAST...AND WL ONLY HAVE POPS ALONG THE CONTDVD THIS MORNING. THIS AFTERNOON THE NAM AND GFS SHOW THE BEST PCPN CHANCES BEING OVR THE CENTRAL CO MTS AND OVR PIKES PEAK AND TELLER COUNTY. THE NSSL WRF SHOWS PCPN IN THESE AREAS AS WELL...BUT ALSO SHOWS A BAND OF PCPN MOVING FROM THE SW ACRS THE SWRN MTS...THE SAN LUIS VALLEY...THE SANGRE DE CRISTO MTS...AND THEN ONTO THE ADJACENT I-25 CORRIDOR BY EARLY EVENING...AND THEN MOVING ACRS THE SERN PLAINS THRU THE EVENING. WL LEAN CLOSER TO THE WRF`S SOLUTION. SHOULD SEE SOME LIGHT SNOW ACCUMS OVR THE HIGHEST ELEVATIONS. TEMPS TODAY WL BE COOLER THAN YESTERDAY OVR THE SERN PLAINS IN THE WAKE OF THE FRONT...BUT GUIDANCE TEMPS ARE NOT IN GOOD AGREEMENT SO WL SPLIT THE DIFFERENCE. COULD SEE SOME LOW CLOUDS HANGING AROUND OVR THE FAR SERN CORNER INTO THE AFTERNOON WHICH WOULD KEEP TEMPS EVEN COOLER OUT THERE. SOME WRN AREAS WL BE A LITTLE COOLER TODAY...WHILE THE SAN LUIS VALLEY WL LIKELY SEE TEMPS SIMILAR TO THOSE ON SUN. OVERNIGHT THE UPR LOW WL MOVE INTO ERN UT AND MUCH OF THE FORECAST AREA ENDS UP IN THE DRY SLOT...AS SHOW IN THE NAM12...THE NSSL WRF AND THE GFS. THE CENTRAL MTS WL PROBABLY CONTINUE TO HAVE SOME PCPN THRU THE NIGHT...BUT SHOULD GENERALLY BE LIGHT. WITH MOIST LOW LEVEL UPSLOPE OVR THE ERN PLAINS TONIGHT...WIDESPREAD STRATUS IS EXPECTED. THE ONLY AREA THAT ALL THE MODELS SHOW WIDESPREAD PCPN TONIGHT IS OVR THE FAR SERN PLAINS...SO WL GO WITH LIKELY POPS IN THAT AREA...WITH DECREASING POPS WESTWARD TO THE ERN MTS. THE NAM AND GFS SHOW A FEW HUNDREDTHS OF PCPN OVR THE FAR ERN AREAS OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 AM MDT MON APR 1 2013 TUESDAY AND WEDNESDAY...THE UPPER LOW PRES SYSTEM TRACKS FROM THE NW TO THE SE DIRECTLY ACROSS COLORADO ON TUE AND WED...BRINGING A DECENT SHOT AT SOME PCPN FOR THE FORECAST AREA. STARTING OUT TUE MORNING...THE UPPER SYSTEM SHOULD BE PRODUCING SOME SHOWERS FOR THE CENT MTS...WHILE LLVL EASTERLY UPSLOPE FLOW DUE TO SFC HI PRES OVER NE AND KS WILL KEEP A SOLID THREAT OF PCPN FOR THE EASTERN PLAINS. HOWEVER...AS THE UPPER LOW CONTINUES TO TRACK ACROSS THE STATE...PCPN CHANCES SPREAD TO MUCH OF THE AREA BY TUE AFTN AND REMAIN PROBABLE THROUGH THE NIGHT. ONGOING POP GRIDS LOOKED REASONABLE FOR TUE NIGHT AND EARLY WED MORN WITH ONLY SLIGHT ADJUSTMENTS NEEDED. THE TROUGH AXIS EXITS THE SE CORNER OF THE STATE WED MID-MORNING...WITH PCPN THEN TAPERING OFF QUICKLY. AS FOR TEMPS...MAX TEMPS IN THE 40S FOR TUE WILL GRADUALLY WARM INTO THE 50S FOR WED. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT..THE REGION DRIES OUT AS AN UPPER RIDGE OF HIGH PRESSURE MOVES ACROSS THE 4 CORNERS. TEMPS SHOULD REMAIN COOL FOR WED...THEN REBOUND INTO THE MID TO UPPER 60S FOR THU. FRIDAY THROUGH SUNDAY...THE EXTENDED MODELS WANT TO KEEP THINGS A BIT UNSETTLED OVER THE WEEKEND. ONE DISTURBANCE ROLLS ACROSS THE ROCKIES ON FRIDAY BUT LOOKS LIKE IT WILL STAY MAINLY TO THE NORTH OF THE STATE. A BRIEF BREAK ON SAT...THEN SAT NIGHT ANOTHER SHORTWAVE TRACKS ACROSS THE GREAT BASIN AND DIGS FURTHER SOUTH...PROMISING A BETTER SHOT AT SOME BENEFICIAL PCPN. FOR THE TIME BEING...KEPT ISOLATED POPS OVER THE MTS OVER THE WEEKEND AS THE EXTENDED PROCEDURE PRODUCED...AND WILL HAVE TO FINE TUNE AS THAT WINDOW NEARS. FOR THE TIME BEING...FRIDAY LOOKS LIKE THE WARMEST DAY OF THE EXTENDED FORECAST PERIOD. MOORE && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1121 AM MDT MON APR 1 2013 I DO NOT EXPECT ANY SIGNIF PRECIP IN THE TAFS (KCOS...KPUB...KALS) NEXT 24H. MAIN CONCERN WILL BE LOW CIGS MOVING INTO KCOS AND KPUB AROUND MIDNIGHT TONIGHT AND LASTING THROUGH THE END OF THE TAF PD. MVFR CIGS ARE LIKELY AT KPUB AND KCOS AFTER MIDNIGHT TONIGHT. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HODANISH SHORT TERM...28 LONG TERM...MOORE AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1018 AM MDT MON APR 1 2013 .UPDATE...NO CHANGES TO THE FORECAST ANTICIPATED THIS TIME AROUND. UPPER LOW CENTER HAS MOVED INTO SOUTHWESTERN UTAH WITH DEFORMATION BAND CLOUDINESS OUT AHEAD OF IT SPREADING OVER WESTERN AND CENTRAL COLORADO. RECENT LIGHTNING DATA PLOTS HAVE SHOWN SOME STRIKES TO THE SOUTH OF VERNAL...UTAH AND ONE OR TWO FLASHES AROUND KGJT. THIS IS INDICATIVE OF THE INSTABILITY PRESENT IN THE DEFORMATION ZONE. THE CURRENT FORECASTS ALREADY MENTION SOME THUNDER OVER THE MOUNTAINS THIS AFTERNOON...WHICH WILL BE LEFT ALONE. KCCU IS ALSO INDICATING SOME SNOW ALREADY FALLING OVER THE HIGHER MOUNTAINS. ACROSS THE EASTERN COLORADO PLAINS...EASTERLY FLOW WILL PERSIST THROUGH THE DAY WHICH MAY HELP SHOWER ACTIVITY TO DEVELOP ALONG THE FOOTHILLS LATE IN THE AFTERNOON. EACH OF THESE FEATURES IS ADEQUATELY COVERED IN THE CURRENT FORECAST. && .AVIATION...HIGH CEILINGS WILL BE DEVELOPING BY EARLY AFTERNOON AND THEN BEGIN LOWERING BY EVENING. SCATTERED SHOWERS WILL BE POSSIBLE THROUGH THE EVENING...BUT MOST ACTIVITY SHOULD BE CLOSER TO THE FOOTHILLS. WINDS SHOULD REMAIN OUT OF THE EAST AND SOUTHEAST THROUGH THE AFTERNOON. A MIX OF RAIN AND SNOW SHOWERS ARE EXPECTED OVERNIGHT WITH A COMPLETE CHANGEOVER TO SNOW POSSIBLE BEFORE SUNRISE TUESDAY. TEMPERATURES SHOULD BE JUST COLD ENOUGH TO ALLOW SNOW TO FALL...BUT GROUND TEMPERATURES SHOULD BE WARM ENOUGH TO LIMIT ANY ACCUMULATION. && .PREV DISCUSSION... /ISSUED 340 AM MDT MON APR 1 2013/ SHORT TERM...AN UPPER LEVEL LOW WILL MOVE FROM NEVADA INTO UTAH BY THIS EVENING. AHEAD OF THE LOW THE FLOW ALOFT WILL BE SWLY. AT THE SURFACE HIGH PRES WILL BE OVER THE CNTRL PLAINS WITH LOW PRES OVER WRN COLORADO. THIS WILL LEAD TO SELY LOW LVL FLOW OVER NERN CO THRU TONIGHT. CROSS- SECTIONS SHOW AN INCREASE IN MOISTURE WITH SOME MID LVL QG ASCENT MAINLY LATE TONIGHT. LAPSE RATES ARE BEST OVER THE HIGHER TERRAIN WITH LESS INSTABILITY OVER THE PLAINS. AT THIS TIME THE BEST CHC OF PCPN THRU THIS AFTN LOOKS TO BE IN THE MTNS WITH DRY CONDITIONS OVER THE PLAINS. WILL MENTION SOME THUNDER IN THE MTNS WHERE SOME CAPE EXISTS. HIGHS THIS AFTN OVER NERN CO WILL RANGE FM THE UPPER 40S TO LOWER 50S EXCEPT POSSIBLY ALONG THE FRONT RANGE WHERE SELY LOW LVL WINDS COMING OFF THE PALMER DIVIDE COULD ALLOW FOR READINGS TO RISE INTO THE MID TO UPPER 50S NR DENVER. THE RAP SHOWS HIGHS IN THE LOWER TO MID 60S AROUND DENVER HOWEVER WILL NOT GO THIS WARM. FOR TONIGHT SNOW SHOWERS WILL CONTINUE IN THE MTNS DUE TO INCREASING QG ASCENT HOWEVER SWLY OROGRAPHIC FLOW MAY KEEP ACCUMULATIONS ON THE LIGHT SIDE IN MOST AREAS. EAST OF THE MTNS THE LOW LVL FLOW WILL REMAIN SELY. SHOULD SEE SOME SHOWERS DVLP IN THE FOOTHILLS BY EARLY EVENING WITH SOME OF THE ACTIVITY SPREADING ACROSS THE ADJACENT PLAINS OVERNIGHT. WITH SELY LOW LVL FLOW THE BEST CHC OF PCPN MAY FOCUS IN THE NRN FOOTHILLS AND NORTH OF A DENVER TO LIMON LINE. AT THIS TIME OVERALL CONFIDENCE IS NOT VERY HIGH AS TO WHERE TO MENTION LIKELY POPS OVER THE PLAINS TONIGHT SO WILL KEEP POPS IN THE CHC CATEGORY. SOUNDINGS SHOW WET BULB ZEROS WILL BECOME LOW ENOUGH FOR SHOWERS TO MIX WITH OR CHANGE TO SOME SNOW AFTER MIDNIGHT ACROSS THE PLAINS HOWEVER AT THIS TIME IT LOOKS LIKE ANY ACCUMULATION WILL BE AN INCH OR LESS. LONG TERM...MODELS HAVE THE UPPER CLOSED LOW OVER EAST CENTRAL UTAH...THEN OVER THE FOUR CORNERS AT 00Z TUESDAY AFTERNOON. BY 18Z WEDNESDAY...ITS OVER SOUTHEASTERN/ WESTERN KANSAS. ON WEDNESDAY NIGHT...INCREASING NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THE FORECAST AREA. THE QG VERTICAL VELOCITY FIELDS HAVE UPWARD MOTION OVER THE CWA TUESDAY AND TUESDAY NIGHT ...HOWEVER IT IS NOT VERY STRONG. WEAK DOWNWARD MOTION IS PROGGED WEDNESDAY AND WEDNESDAY NIGHT. NORTHEAST TO SOUTHEASTERLY LOW LEVEL WINDS ARE PROGGED FOR THE PLAINS AND FOOTHILLS TUESDAY AND TUESDAY EVENING. WEAK FLOW IS PROGGED THE REST OF TUESDAY NIGHT THROUGH WEDNESDAY...WITH A COMBINATION OF NORMAL DUIRNAL PATTERNS TO WEAK DOWNSLOPING WEDNESDAY NIGHT. MOISTURE IS FAIRLY DEEP ON TUESDAY FOR MOST OF THE CWA. IT IS PRETTY DEEP ON THE NAM TUESDAY NIGHT...DRIER ON THE GFS. IT DRIES OUT SOMEWHAT ON WEDNESDAY. THERE IS SOME MOUNTAIN MOISTURE WEDNESDAY NIGHT...BUT ITS DRIER ON THE PLAINS. MODELS SHOW MINOR CAPE OVER THE MOUNTAINS AND FOOTHILLS LATE DAY TUESDAY AND AGAIN WEDNESDAY AFTERNOON. THE QPF FIELDS SHOW MEASURABLE PRECIPITATION TUESDAY AND TUESDAY EVENING FOR MOST AREAS...BEST OVER THE FOOTHILLS AND EASTERN MOUNTIANS ZONES. THERE IS A TAD THE REST OF TUESDAY NIGHT AND WEDNESDAY... MAINLY OVER THE MOUNTIANS. FOR POPS...WILL KEEP THE "LIKELY"S IN OVER THE MOUNTAINS AND "CHANCES" OUT ON THE PLAINS TUESDAY AND TUESDAY EVENING. THE PLAINS WILL SEE BOTH SNOW AND RAIN...WITH LITTLE ACCUMULATION. WILL DECREASE POPS THE REST OF TUESDAY NIGHT. ON WEDNESDAY...JUST SOME MINOR ALPINE POPS. WILL PUT "ISOLATED" THUNDER IN BOTH TUESDAY AND WEDNESDAY AFTERNOONS IN THE MOUNTIANS. FOR TEMPERATURES...TUESDAY`S HIGHS ARE 2.0-3.5 C COOLER THAN TODAY`S EXPECTED HIGHS. WEDNESDAY`S READINGS COME UP 3-7 C FROM TUESDAY`S. FOR THE LATER DAYS...THURSDAY THROUGH SUNDAY...MODELS HAVE UPPER RIDGING FOR COLORADO THROUGH MID DAY FRIDAY...THEN A WEAK UPPER TROUGH IS PROGGED ACROSS THE STATE BY EARLY SATURDAY MORNING. AFTER THAT...WEST-SOUTHWESTERLY FLOW ALOFT IS PROGGED OVER THE CWA THROUGH SUNDAY. THERE IS LIMITED MOISTURE AROUND...BUT IT INCREASES ON SUNDAY. AVIATION...SO FAR ANY STRATUS WAS CONFINED TO THE FAR NERN CORNER OF THE PLAINS SO AT THIS POINT IT DOES NOT APPEAR IT WILL AFFECT THE AIRPORT THIS MORNING. AS FOR WINDS BOTH THE RAP AND HRR SHOW A DENVER CYCLONE DEVELOPING SW OF DENVER WITH WINDS BEING E TO SE THRU THE AFTN. COULD SEE SUSTAINED WINDS IN THE 15 TO 20 MPH BY 20Z. AT THIS TIME ANY CHC FOR RAIN SHOWERS WILL BE AFTER 00Z. COULD SEE SHOWERS CHANGE TO SOME SNOW AFTER MIDNIGHT BUT ANY ACCUMULATION WILL BE UNDER ONE HALF INCH AND CONFINED TO GRASSY AREAS. LATEST NAM CONTINUES TO SHOW A CYCLONE OVERNIGHT OVER DENVER WITH WINDS BECOMING MORE SLY AFTER MIDNIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DANKERS LONG TERM....99 AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS MIAMI FL
150 PM EDT MON APR 1 2013 .AVIATION... SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE DEVELOPING ACROSS THE EASTERN PORTION OF THE PENINSULA THIS AFTERNOON. FOR THE VERY SHORT TERM...SHOWERS AND THUNDERSTORMS ARE IN THE VICINITY OF TERMINALS KTMB...KMIA AND KOPF WITH BRIEF PERIODS OF IFR CONDITIONS POSSIBLE. THERE IS A SLIGHT RISK OF SEVERE WEATHER WITH ANY THUNDERSTORMS THAT DEVELOP THIS AFTERNOON AND EARLY EVENING. AFTER THE EARLY EVENING HOURS THE POTENTIAL FOR CONVECTION WILL START TO DECREASE. FOR THE EAST COAST TERMINALS...AS SOUTHWESTERLY WINDS CONTINUE TO DEVELOP THE CHANCES OF A SEA BREEZE THIS AFTERNOON ARE DIMINISHING BUT WINDS COULD BE SOMEWHAT VARIABLE AT TIMES. 60 && .PREV DISCUSSION... /ISSUED 1031 AM EDT MON APR 1 2013/ UPDATE... THE MORNING SURFACE ANALYSIS SHOWED A HIGH PRESSURE RIDGE AXIS EXTENDING WEST ACROSS SOUTH FLORIDA AND THE SOUTHEAST GULF OF MEXICO AND A COLD FRONT APPROACHING FROM THE NORTH. SSW LOW-LEVEL FLOW IS EXPECTED TO GRADUALLY VEER TOWARD THE WEST THROUGH THE COURSE OF THE DAY AS THIS BOUNDARY CONTINUES SOUTH. THIS FLOW COMBINED WITH THE AFTERNOON EAST COAST SEA BREEZE...A COUPLE OF IMPULSES ALOFT AND MODERATE INSTABILITY AND SHEAR (0-6KM 30-35 KT) COULD GENERATE A FEW STRONG TO EVEN SEVERE THUNDERSTORMS THROUGH THE AFTERNOON/EVENING PERIOD TODAY OVER THE METRO/EAST COAST LOCATIONS. THE LATEST WRF AND HRRR MODEL REFLECTIVITIES... HOWEVER...ARE ONLY INDICATING ISOLATED COVERAGE OVER THESE AREAS AT BEST THROUGH THIS TIME. ANY STORMS THAT DO INITIATE COULD BE CAPABLE OF PRODUCING STRONG WINDS, HAIL AND POSSIBLY A TORNADO. THE LATEST FORECAST HAS BEEN UPDATED TO REFLECT THIS POTENTIAL THIS AFTERNOON. ELSEWHERE...VISIBILITIES HAVE BEGUN TO IMPROVE OVER THE PAST HOUR ACROSS THE INTERIOR LOCATIONS FROM THE EARLY MORNING FOG AND THIS TREND IS EXPECTED TO CONTINUE. THE LOCAL OFFICIALS HAVE REPORTED THAT SEGMENTS OF I-75 HAVE BEEN CLOSED TODAY DUE TO A COMBINATION OF THIS FOG EARLIER AND SMOKE FROM THE ONGOING WILDFIRE IN COLLIER COUNTY. PREV DISCUSSION... /ISSUED 739 AM EDT MON APR 1 2013/ AVIATION... AN UPPER LEVEL SHORTWAVE ACROSS THE EASTERN GULF WILL MOVE ACROSS THE FLORIDA PENINSULA TODAY. A FEW SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MAINLY TO THE EAST OF THE EAST COAST TAF SITES THIS MORNING. SEA BREEZE BOUNDARIES EARLY THIS AFTERNOON ARE EXPECTED TO HELP GENERATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NEAR THE EAST COAST TAF SITES. SO ADDED VCTS FOR THE EAST COAST TAFS. FOR KAPF...THERE IS A SLIGHT CHANCE OF SHOWERS AHEAD OF THE TROUGH...MAINLY BEFORE 18Z. WIND DIRECTION MAY VARY BETWEEN 160-210 DEGREES DURING THE DAY AT THE EAST COAST TAF SITES. WINDS WILL SHIFT TO THE WEST TO NORTHWEST TONIGHT BEHIND THE BOUNDARY. PREV DISCUSSION... /ISSUED 459 AM EDT MON APR 1 2013/ DISCUSSION... CURRENTLY, A MID LEVEL TROUGH, ROUGHLY AT 700 MB, IS MOVING ACROSS THE EASTERN GULF OF MEXICO. THIS HAS GENERATED A LINE OF THUNDERSTORMS THAT IS EXPECTED TO FALL APART AS IT APPROACHES CENTRAL FLORIDA. THIS TROUGH, ACCORDING TO THE HRRR, MAY SPARK OFF A FEW SHOWERS OVER SOUTH FLORIDA THIS MORNING. ALSO, ANOTHER SHORT WAVE HAS GENERATED SOME SHOWERS AND ISOLATED THUNDERSTORMS OVER THE FLORIDA STRAITS. THESE ARE MOVING NORTH NORTHEAST. THE SHOWERS WILL AFFECT THE SOUTHEASTERN PORTION OF THE CWA THIS MORNING. THE QUESTION IS IF THERE WILL BE ANY THUNDERSTORMS THAT MOVE INTO THE AREA AS WELL. THERE IS AROUND 1000 JOULES JUST ONSHORE, AROUND HOMESTEAD AND MIAMI. SO, ALTHOUGH ORIGINAL THINKING WAS THEY WOULD STAY OFFSHORE, MAY HAVE TO ADD A MENTION OF THUNDERSTORMS FOR THIS AREA THIS MORNING. AS FOR LATER TODAY, MODELS INDICATE THE TROUGH, OR REALLY, A WEAKENING FRONT, WILL MOVE ONSHORE THE GULF COAST LATER THIS MORNING. MODELS ARE INDICATING IT WILL NOT BE TOO ACTIVE, CONVECTION WISE WHEN IT DOES. BUT, AS IT PROGRESS ACROSS THE STATE, ALONG WITH DAYTIME HEATING, CONVECTION MAY BE ABLE TO INITIATE. THE MODELS DO DIFFER GREATLY WITH HOW MUCH CAPE WILL BE AVAILABLE. THE GFS KEEPS THE HIGHEST BOUNDARY LAYER CAPE VALUES WELL OFFSHORE AND ONLY 500-600 JOULES OVER THE ATLANTIC COAST. THE NAM, ON THE OTHER HAND, HAS 1200 TO 1600 JOULES OVER THE ATLANTIC COAST, NEAT WEST PALM BEACH, AND DROPS TO 500-700 JOULES NEAR MIAMI. NOW THE NAM MODEL SOUNDINGS HAVE 1200-1600 JOULES ALL OVER THE ATLANTIC COAST. THEY DO SHOW A WEAK CAP FURTHER NORTH, BUT IT IS SO WEAK, NOT THINKING IT WILL BE A REAL INHIBITOR. THERE IS ALSO A TOUCH OF CIN TO THE NORTH AS WELL, BUT AGAIN, NOTHING THAT REALLY SHOULD INHIBIT DEVELOPMENT. SO, WHAT WILL INHIBIT THEIR DEVELOPMENT. WELL, MODELS DO SHOW THAT THE CAPE WILL BE PUSHING OFF TO THE EAST, AHEAD OF THE TROUGH. SO, WE MAY BE LACKING THE LIFTING MECHANISM. IT MAY ARRIVE WELL AFTER THE CAPE HAS PUSHED OFF SHORE. SO, HAVE KEPT CHC POPS AND SLIGHT CHC TSTMS, BUT HAVE BROADENED THE COVERAGE OF TSTMS THIS AFTERNOON. BEHIND THE TROUGH TODAY, HIGH PRESSURE WILL BE BUILDING IN FAIRLY QUICK. THIS WILL BRING QUIET WEATHER BACK TO SOUTH FLORIDA FOR A FEW DAYS. FOR FRIDAY AND THE WEEKEND, A LOW PRESSURE SYSTEM WILL DEVELOP OVER THE WESTERN GULF AND MOVE OVER THE FLORIDA PANHANDLE THURSDAY NIGHT/FRIDAY MORNING. A COLD FRONT WILL MOVE THROUGH SOUTH FLORIDA FRIDAY. THIS SYSTEM WILL BRING OUR NEXT CHANCE FOR RAIN AND POSSIBLY A THUNDERSTORM. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE STRENGTH, POSITION, AND TIMING OF THIS SYSTEM. GIVEN THIS, HAVE A HIGH CHC POP IN THE FORECAST FOR FRIDAY. BEHIND THE FRONT, HIGH PRESSURE WILL BUILD IN ONCE AGAIN. TEMPERATURES WILL NOT BE MUCH COOLER, ONLY A FEW DEGREES. THIS HIGH PRESSURE WILL LAST FOR THE REMAINDER OF THE EXTENDED FORECAST. MARINE... WINDS AHEAD OF A WEAK FRONT/TROUGH WILL PICK UP OUT OF THE SOUTH TO BETWEEN 13 AND 19 KTS OVER THE ATLANTIC WATERS. THEY SHOULD REMAIN BELOW 10 KTS OVER THE GULF WATERS. THE HIGHER WIND SPEEDS OVER THE ATLANTIC WATERS HAS PROMPTED A SMALL CRAFT SHOULD EXERCISE CAUTION STATEMENT FOR THIS AFTERNOON. SEAS TODAY WILL BE SUBSIDING SOMEWHAT, EVEN WITH THE WINDS, AND ARE EXPECTED TO BE 1 TO 3 FEET BY TOMORROW IN THE ATLANTIC WATERS. THE GULF WATERS WILL BE AROUND 1 FOOT FOR THE NEXT COUPLE OF DAYS. HIGH PRESSURE WILL BUILD IN BEGINNING TONIGHT. THIS WILL CAUSE WINDS TO WEAKEN SOME TONIGHT TO 7-10 KTS OVER THE ATLANTIC AND SHIFT THEM OUT OF THE NORTH TOMORROW. FIRE WEATHER... THE MAIN FIRE WEATHER CONCERN TODAY ARE THE SHIFTING WINDS. AN APPROACHING FRONT/TROUGH WILL CAUSE WINDS TO PICK UP SOME TODAY TO 10 TO 15 MPH OVER GLADES, HENDRY, AND INTERIOR COLLIER COUNTIES. THEY WILL BEGIN OUT OF THE SOUTHEAST, BUT TURN THROUGH THE DAY TO THE SOUTH, THEN SOUTHWEST BY EARLY AFTERNOON. BY THIS EVENING, THEY WILL BECOME WESTERLY BETWEEN 5 AND 10 MPH. ALONG WITH THIS WIND SHIFT, WILL BE THE CHANCE FOR SOME RAIN SHOWERS AND A SLIGHT CHANCE FOR A THUNDERSTORM. THE CHANCES INCREASE AS YOU GO EASTWARD ACROSS SOUTH FLORIDA. IN THE INTERIOR PORTION OF THE AREA, THE DIVIDING LINE FOR THE CHANCE OF AND THUNDERSTORMS IS A DIFFICULT ONE AT BEST. SO, AREAS WEST OF THE FORECASTED AREA, SHOULD REMAIN AWARE OF THE POSSIBILITY THAT THE FORECAST COULD CHANGE TO INCLUDE THEM AS THE TROUGH GETS CLOSER. ONE THE OTHER HAND, IT COULD ALSO BE PUSHED FURTHER EAST. THERE IS JUST GREAT UNCERTAINTY WITH THE CONVECTIVE DEVELOPMENT TODAY. BEHIND THE TROUGH, HIGH PRESSURE WILL BUILD IN THROUGH THURSDAY, BRINGING QUIET WEATHER BACK TO SOUTH FLORIDA. PREV DISCUSSION... /ISSUED 241 AM EDT MON APR 1 2013/ AVIATION... ISOLATED SHOWERS WERE MOVING ACROSS THE ATLANTIC WATERS AND NEAR KFLL AND FXE. ANOTHER AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS WERE MOVING JUST SOUTH OF THE KEYS. THIS AREA OF SHOWERS AND STORMS WILL CONTINUE TO MOVE NORTHWARD OVERNIGHT...AND COULD GET NEAR KTMB AND KMIA IN THE NEXT FEW HOURS IF THEY HOLD TOGETHER. A SHORTWAVE TROUGH MOVING ACROSS THE EASTERN GULF WAS FORCING SHOWERS AND THUNDERSTORMS TO DEVELOP WEST OF TAMPA. THE HRRR KEEPS THIS LINE TOGETHER AND MOVES IT TOWARDS KAPF AROUND 16Z. OTHER SHOWERS OR STORMS COULD ALSO BEGIN DEVELOPING ON THE EAST COAST SEA BREEZE AROUND THIS TIME. THE WIND DIRECTION IS ALSO TRICKY TODAY AS THE BOUNDARY LAYER WINDS SHIFT TO THE SOUTHWEST AHEAD OF THE TROUGH AND WEAK COLD FRONT. SO THE WINDS MAY SHIFT TO THE SOUTHWEST FOR A TIME LATE IN THE MORNING BEFORE THE EAST COAST SEA BREEZE BOUNDARY TRIES TO PUSH THE WINDS BACK TO THE SOUTH OR SOUTHEAST. BY 00Z...SOUTHWESTERLY FLOW IS EXPECTED TO PREVAIL...WITH WEST TO NORTHWESTERLY FLOW BEHIND THE SURFACE TROUGH AFTER 02-04Z. SO FOR THE TAFS...KEPT VCSH FOR NOW...BUT MAY NEED TO ADD VCTS. MVFR CONDITIONS ARE POSSIBLE NEAR ANY SHOWERS OR STORMS THAT FORM. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 65 81 67 81 / 20 10 - 10 FORT LAUDERDALE 68 84 71 83 / 20 10 - 10 MIAMI 68 85 69 82 / 20 10 - 10 NAPLES 65 83 64 85 / 10 10 - 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
350 PM EDT MON APR 1 2013 ...BRIEF DRY PERIOD BEFORE RAIN RETURNS MID WEEK... .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... LATEST SURFACE ANALYSIS SHOWS SEMI PERMANENT SURFACE TROUGH FROM JUST SOUTH OF ATHENS THROUGH COLUMBUS. ALONG AND SOUTH OF THIS FEATURE MOISTURE SURFACE CONVERGENCE HAS RESULTED IN SCATTERED TO BROKEN CU DEVELOPMENT BUT SHOWER ACTIVITY HAS REMAINED OUTSIDE OF THE FORECAST AREA. FURTHER NORTH...SURFACE FRONT CONTINUES TO SAG INTO NORTH GA WITH MOISTURE POOLING ALONG ITS LEADING EDGE AS WELL AND ADDITIONAL CLOUD DEVELOPMENT THE RESULT. THIS SHOULD REMAIN JUST CLOUDS WITH NO PRECIP FOR THIS EVENING AS MAIN FOCUS WILL BE ON SOUTHERN TROUGH AND IT AFFECTS ON CENTRAL GEORGIA. LOOKING AT THE LATEST RAP ANALYSIS OF CAPE IN THIS VICINITY AND WE SEE 500 J/KG TO 1000 J/KG OF AVAILABLE ENERGY...SLIGHTLY HIGHER THAN MODEL PROJECTIONS. STILL LOOKING AT 500MN TEMPS IN THE VERY COLD RANGE OF -17C IN THIS AREA SO ANY SUSTAINED UPDRAFTS WILL BE CAPABLE OF PRODUCING LARGE HAIL. ACTIVITY WILL SHIFT EAST QUICKLY THIS EVENING WITH CLEARING CONDITIONS TAKING PLACE. STILL SOME GRADIENT IN PLACE ACROSS THE AREA WHICH WILL PREVENT OPTIMUM RADIATIONAL COOLING CONDITIONS. WENT WITH A MAV/MET BLEND FOR THE OVERNIGHT TEMPS WHICH WILL BE TRICKY TO THE SOUTH BASED ON HOW FAST CLOUDS CLEAR. SURFACE FRONT LOOKS TO STALL ACROSS NORTH GEORGIA TUESDAY AND IMPULSES OF ENERGY BEGIN TO ROUND PERIPHERY OF EAST COAST TROUGH. THIS SHOULD ALLOW A FEW LIGHT SHOWERS TO DEVELOP ACROSS EXTREME NORTH GEORGIA AND HAVE INCLUDED IN THIS GRID PACKAGE. AS HIGH BRIDGES ACROSS THROUGH TUESDAY NIGHT...MAY SEE FRONT SAG FURTHER SOUTH AND TAKE 20 POPS ALONG WITH IT INTO THE REMAINDER OF NORTH GEORGIA. DEESE .LONG TERM /WEDNESDAY THROUGH MONDAY/... MAIN CONCERN FOR THE EXTENDED REMAINS THE SYSTEM MOVING THROUGH THE STATE ON WEDNESDAY INTO THE END OF THE WORK WEEK. DISCREPANCIES STILL REMAIN BETWEEN THE EURO AND GFS AS FAR AS TIMING OF THE SYSTEM LEAVING THE CWA. THE 12Z MODELS ARE STRIKINGLY SIMILAR TO THEIR OOZ COUNTERPARTS. AS SUCH...WAS NOT ABLE TO NAIL DOWN AN ACCURATE END TO THE RAIN THIS WEEK. ACCORDING TO HPC MODEL DISCUSSIONS THE EURO IS AN OUTLIER...MOVING THE SYSTEM FURTHER SOUTH AND IS SLOWER. THAT SAID THEY DECIDED TO WITH A BLEND BETWEEN THE 00Z EURO AND THE 06Z GEFS. WITH THIS MUCH UNCERTAINTY DECIDED TO ONLY CHANGE THE COVERAGE OF THUNDER ON WEDNESDAY AND LEAVE THE REST OF THE FORECAST ALONE. DID LOWER TEMPS ON THURSDAY AS A PSEUDO WEDGE BUILDS IN. CLOUDS AND RAIN IN ASSOCIATION WITH THIS WEDGE SHOULD HELP TO KEEP TEMPS LOW. HAVE INCLUDED PREVIOUS EXTENDED BELOW/ ARG && LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... POTENTIAL FOR A HEAVY RAIN/SEVERE WEATHER EVENT SETTING UP IN THE THURSDAY TO THURSDAY NIGHT TIME FRAME. MODELS SIMILAR WITH SPREADING DEEPER MOISTURE INTO THE AREA LATE WEDNESDAY BUT THE MAIN PRECIP PERIOD LOOKS TO BE WEDNESDAY NIGHT THRU THURSDAY NIGHT. AN OVERRUNNING PATTERN WILL SET LATE WEDNESDAY/WEDNESDAY NIGHT WITH MODELS DEVELOPING A WARM FRONT ALONG THE GULF COAST. SURFACE LOW PRESSURE DEVELOPS OVER THE WESTERN GULF AND MOVES TO THE WESTERN FL PANHANDLE LATE THURSDAY AND THEN ACROSS CENTRAL TO S GA THURSDAY NIGHT/FRIDAY. THE GFS IS FASTER WITH THIS PROGRESSION THAN THE EUROPEAN. THIS TRACK COULD MOVE THE WARM FRONT INTO THE SE CWA AND GIVE POTENTIAL FOR SEVERE THUNDERSTORMS MAINLY THURSDAY NIGHT. IT WILL ALSO GIVE POTENTIAL FOR HEAVY RAIN ACROSS A LARGE PORTION OF EAST GEORGIA AND MODELS IN GENERAL ARE LESS GUN-OH WITH PRECIP AMOUNTS WITH A LARGE AREA OF 1-2 INCHES FORECAST. THE UPPER TROUGH MOVES ACROSS THE AREA ON FRIDAY AND THE GFS IS FASTER WITH THIS PROGRESSION THAN THE EUROPEAN. THE AIRMASS DRIES OUT FOR SATURDAY AND MOSTLY LIKELY SUNDAY WITH THE EUROPEAN INDICATING SOME MOISTURE ASSOCIATED WITH A SHORT WAVE ON SUNDAY...MOST SO FOR N GA. FOR NOW WILL KEEP THINGS DRY AND MONITOR THE PROGRESSION. A SHORT WAVE RIDGE BUILDS FOR MONDAY WITH THE EUROPEAN CONTINUING TO SHOW MORE MOISTURE SKIRTING OVER N GA THAN THE GFS. BDL AVIATION... 18Z UPDATE... VFR FORECAST IN STORE AS MAIN CLOUD SHIELD HAS SLIPPED TO THE SOUTH OF THE TERMINALS. WILL BE WATCHING SECONDARY AREA OF CLOUDS DEVELOPING OVER EXTREME NORTH GA IN ENHANCED MOISTURE ZONE BUT JUST PLAYING AS FEW050 FOR NOW. OTHERWISE...STILL UNCERTAINTY WITH WIND SHIFT POTENTIAL MID MORNING TUESDAY WITH NW VS NE STILL IN QUESTION FOR ATL. WENT WITH CONSENSUS OF NW FOR NOW WHICH AGREES WITH PARTNERS AND CONSENSUS. //ATL CONFIDENCE...18Z UPDATE... MEDIUM ON WIND SHIFT. HIGH ON REMAINING ELEMENTS. DEESE && .PRELIMINARY POINT TEMPS/POPS... ATHENS 42 69 41 64 / 10 10 20 20 ATLANTA 47 67 44 64 / 5 5 20 20 BLAIRSVILLE 37 58 35 63 / 10 10 20 20 CARTERSVILLE 41 65 40 64 / 5 10 20 20 COLUMBUS 51 75 50 70 / 5 5 5 30 GAINESVILLE 44 65 43 61 / 10 10 20 20 MACON 45 75 44 69 / 5 5 5 30 ROME 38 65 38 64 / 5 10 20 20 PEACHTREE CITY 40 70 42 65 / 5 5 20 30 VIDALIA 55 76 51 74 / 20 0 5 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DEESE LONG TERM....ARG AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS WICHITA KS
1230 PM CDT MON APR 1 2013 .UPDATE... ISSUED AT 1229 PM CDT MON APR 1 2013 PUT OUT ANOTHER UPDATE TO ADD LIGHT SNOW AS A PRECIP TYPE BASED ON LATEST REPORTS. HOWEVER THE BIGGER REASON FOR THE UPDATE WAS TO DROP HIGHS TODAY SEVERAL DEGREES. ISENTROPIC LIFT NORTH OF THE SURFACE COLD FRONT HAS RESULTED IN NUMEROUS RAIN/SNOW SHOWERS ACROSS MOST OF SOUTH CENTRAL KS. THIS ACTIVITY SHOULD CONTINUE TRACKING OFF TO THE EAST-SOUTHEAST THIS AFTERNOON. WITH WARM GROUND TEMPS...NO ACCUMULATION IS EXPECTED. THE INCREASED CLOUD COVER WILL COMBINE WITH TEMPS WET-BULBING DOWN TO KEEP TEMPS FROM CLIMBING MUCH THIS AFTERNOON. SO WENT AHEAD AND DROPPED HIGHS SEVERAL DEGREES. UPDATE ISSUED AT 1013 AM CDT MON APR 1 2013 SENT OUT A QUICK UPDATE TO KEEP UP WITH CURRENT PRECIP TRENDS. ISENTROPIC LIFT ALONG THE 305K SURFACE HAS RESULTED IN PRECIP EXPANDING OVER SW PORTIONS OF THE FORECAST AREA. THIS ACTIVITY SHOULD CONTINUE TO PUSH EAST LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS. A COUPLE RUMBLES OF THUNDER MAY MIX WITH THE SHOWERS. LAWSON && .SYNOPSIS... ISSUED AT 332 AM CDT MON APR 1 2013 A POTENT DISTURBANCE IS PLUNGING SOUTHWARD INTO THE GREAT LAKES REGION...CAUSING A COLD FRONT TO DIVE SOUTHWARD ACROSS THE CENTRAL PLAINS. THE COLD FRONT HAS MADE IT HALF WAY THROUGH KANSAS AS OF THIS ISSUANCE AND WILL CONTINUE TO MOVE SOUTHWARD THROUGH OKLAHOMA DURING THE DAY. WINDS ARE GUSTY BEHIND THE FRONT WITH LOW TO MID LEVEL CLOUDS. LOOKING WEST...ANOTHER DISTURBANCE IS LOCATED OVER MID-CALIFORNIA/NEVADA/UTAH. THIS WILL BE THE WEATHER MAKER FOR THE FIRST PART OF THE WEEK. && .SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT) ISSUED AT 332 AM CDT MON APR 1 2013 THIS PERIOD WILL BE RAINY OFF AND ON AND COOLER FOR MUCH OF SOUTHERN KANSAS. THE LATEST GUIDANCE...NAM/GFS/ECMWF AND HRRR INDICATE PRECIPITATION DEVELOPING ACROSS SOUTH CENTRAL KANSAS AROUND MID AFTERNOON TODAY BEFORE SPREADING EAST ACROSS SOUTHERN KANSAS THROUGH THE DAY AND OVERNIGHT. PRECIPITATION WILL DEVELOP NEAR THE 850MB FRONT. THE UPPER LEVEL WAVE OVER THE WEST WILL CONTINUE TO MOVE TOWARDS THE AREA...ENHANCING UPPER LEVEL SUPPORT. THE 850MB FRONT WILL REMAIN STATIONARY...KEEPING THE PRECIPITATION CHANCES THROUGH WEDNESDAY. NOT EXPECTING THUNDER WITH THIS EVENT WITH VERY LOW MUCAPE VALUES...BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE. THIS PERIOD WILL REMAIN COOLER...AS THE COLD FRONT USHERED IN UNSEASONABLY COOL AIR. WITH COLD AIR ADVECTION...CLOUDY SKIES AND RAIN...TEMPERATURES WILL BE 10 TO 20 DEGREES BELOW NORMAL. TUESDAY LOOKS TO BE THE COOLEST DAY WITH CLOUD COVER AND RAIN. BILLINGS .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 332 AM CDT MON APR 1 2013 BY THURSDAY THE UPPER LEVEL DISTURBANCE THAT WILL IMPACT THE AREA FOR THE FIRST HALF OF THE FORECAST WILL FINALLY BE ON ITS WAY EAST. SURFACE HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY WITH CLEARING SKIES IN THE SUBSIDENCE ZONE OF THE UPPER WAVE. THIS WILL ALLOW TEMPERATURES TO WARM BACK INTO THE UPPER 50S AND LOW 60S. TEMPERATURES WILL CONTINUE TO INCREASE FOR FRIDAY AND SATURDAY AHEAD OF THE NEXT SYSTEM. LEE CYCLOGENESIS WILL DEEPEN AHEAD OF THE NEXT WAVE...WITH STRONG WARM AIR ADVECTION AND MIXING...TEMPS WILL REACH BACK INTO THE 60S AND 70S. THE NEXT DISTURBANCE WILL MOVE ACROSS THE NORTHERN PLAINS...DRAGGING A COLD FRONT ACROSS THE REGION. THE MAIN LIFT ASSOCIATED WITH THIS FRONT WILL BE ACROSS THE NORTHERN PLAINS...SO NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION ALONG THE FRONTAL BOUNDARY AND HAVE LEFT THE FORECAST DRY FOR SATURDAY AND SUNDAY. TEMPERATURES BEHIND THE FRONT WILL ONLY DECREASE SLIGHTLY. ANOTHER WAVE WILL APPROACH FOR THE VERY END OF THE FORECAST AND PRECIPITATION MAY RETURN FOR SUNDAY AND INTO THE EARLY PART OF NEXT WEEK. WILL CONTINUE TO WATCH THIS PERIOD AS THE FORECAST EVOLVES AS THE TIME PERIOD NEARS. BILLINGS && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1229 PM CDT MON APR 1 2013 MAIN AVIATION FORECAST CONCERNS WILL PRECIP THIS AFTERNOON ALONG WITH LOWERING CIGS TONIGHT. THE PRECIP AFFECTING SOUTH CENTRAL KS WILL CONTINUE SLOWLY TRACKING OFF TO THE SOUTHEAST THIS AFTERNOON WITH MAINLY KICT BEING AFFECTED. A RAIN-SNOW MIX WILL BE THE MAIN PRECIP TYPE. THERE SHOULD BE A BREAK IN THE PRECIP LATE THIS AFTERNOON/EARLY THIS EVENING BEFORE ISENTROPIC LIFT GETS CRANKED UP AGAIN AFTER DARK. HOWEVER FOR THIS EVENING FEEL THAT THE BULK OF THE PRECIP WILL BE SOUTH OF THE KS-OK BORDER WITH KICT BEING ON THE NORTHERN FRINGES OF THE PRECIP. IN ADDITION...CIGS WILL START TO LOWER TOWARD SUNRISE ACROSS SOUTH CENTRAL KS WITH KICT POSSIBLY GETTING INTO SOME MVFR CONDITIONS BY 12Z. LAWSON && .FIRE WEATHER... ISSUED AT 332 AM CDT MON APR 1 2013 VERY LITTLE IN THE WAY OF FIRE CONCERN FOR MUCH OF THE FORECAST. LIGHT WINDS AND PRECIPITATION WILL KEEP GRASSLAND FIRE DANGER LOW. WITH STRONGER WINDS AND WARMER TEMPERATURES ON FRIDAY...GRASSLAND FIRE DANGER WILL BE VERY HIGH. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 45 35 43 35 / 80 60 50 30 HUTCHINSON 42 33 45 32 / 50 40 40 20 NEWTON 43 32 43 31 / 50 30 30 20 ELDORADO 45 33 44 33 / 80 40 40 20 WINFIELD-KWLD 49 36 42 36 / 90 70 70 40 RUSSELL 43 30 48 30 / 10 30 20 10 GREAT BEND 42 31 46 31 / 20 30 30 20 SALINA 43 31 50 33 / 10 20 10 10 MCPHERSON 42 32 46 32 / 20 30 20 10 COFFEYVILLE 52 37 44 36 / 70 60 70 40 CHANUTE 48 34 44 34 / 40 30 30 10 IOLA 47 33 45 33 / 20 20 20 10 PARSONS-KPPF 50 35 44 35 / 60 50 50 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
154 PM EDT MON APR 1 2013 .SYNOPSIS... ISSUED AT 422 AM EDT MON APR 1 2013 A SYSTEM IN QUEBEC IS BRINGING COLD AIR AND NORTHWEST WINDS TO THE STATE TODAY. THE COLDER AIR IS PRODUCING LAKE EFFECT SNOW SHOWERS WHICH WILL PERSIST OVER NORTHERN MICHIGAN THROUGH TUESDAY. THE MOST PERSISTENT SNOW SHOWERS WITH THE BEST CHANCE OF ACCUMULATION WILL BE IN THE TYPICAL SNOW BELTS OF NORTHWEST LOWER AND EAST UPPER MICHIGAN. && .UPDATE... ISSUED AT 153 PM EDT MON APR 1 2013 CURRENT FORECAST IS IN LINE. LAKE EFFECT SNOWS CONTINUE OVER NRN MI...AS SFC-850MB WINDS LINGER FROM THE NW AND 850MB TEMPS REMAIN ARND -16C. UPDATE ISSUED AT 951 AM EDT MON APR 1 2013 THE STORM SYSTEM WHICH SWEPT ACROSS THE GREAT LAKES THIS WEEKEND... HAS PUSHED EAST OF THE STATE AND WILL CONTINUE TO LIFT INTO QUEBEC THROUGH TUESDAY. COLD 850MB TEMPS...NORTHWEST WINDS AND LAKE EFFECT SNOWS HAD ALREADY BEGUN TO FILTER INTO NRN MI EARLIER THIS MORNING. 850MB TEMPS DROPPED FROM AROUND 0C SUNDAY AFTERNOON TO ARND -16C BY 12Z THIS MORNING. AS FOR THE REST OF THE AFTN...THE PARAMETERS WHICH ARE CURRENTLY GENERATING LAKE INDUCED SNOWS OVER THE WRN LAKES...ARE NOT EXPECTED TO CHANGE MUCH THROUGH 21Z. 850MB TEMPS WILL LINGER AROUND -16C AS THE AXIS OF THE SFC AND 500MB FEATURES PUSH FURTHER EAST OF THE REGION THIS AFTERNOON. SFC-850MB WINDS WOBBLE DURING THE AFTN...THOUGH REMAIN GENERALLY NW (300-320) WHILE INVERSION HEIGHTS LINGER AROUND 5K FT. OVERALL EXPECT WIDESPREAD LAKE SNOWS TO CONT OVER THE WRN LAKES THROUGH THE AFTN...THOUGH WITH THE HIGH SUN ANGLE...EXPECT DOMINATE SNOW BANDS TO BECOME A LEAST SLIGHTLY DISRUPTED THROUGH THE REST OF THE MORNING. OVERALL WILL KEEP CONT TO MENTION LAKE SNOWS THROUGH THE AFTN. WILL MENTION UP TO 2 INCHES OF SNOW POSSIBLE IN FAVORED SNOW BELTS...AND WILL EXTEND HEADLINES THRU THE AFTN. UPDATE ISSUED AT 708 AM EDT MON APR 1 2013 CHANGES THIS HOUR: ADDITIONAL /UPWARD/ ADJUSTMENTS TO SNOWFALL AS A BAND OF NEARLY 5 INCHES HAS OCCURRED OVER EXTREME SW OTSEGO COUNTY AND NW CRAWFORD COUNTY. BANDING IS MAKING ITS EXPECTED SHIFT EAST...AND IS BEGINNING TO BECOME A LITTLE MORE DIFFUSE. EXPECT WE/VE GOT 2-3 MORE HOURS OF DECENT ACCUMS BEFORE THINGS WIND DOWN. ADVISORY CONTINUES TO LOOK GOOD AND WILL MAKE NO CHANGES TO THIS. UPDATE ISSUED AT 519 AM EDT MON APR 1 2013 CHANGES THIS HOUR: BAND HESITATED LONG ENOUGH FOR ME...AND HAVE ISSUED A WINTER WEATHER ADVISORY FOR 4 OF THE BIG 5 /EXCLUDED KALKASKA/ THROUGH NOON. RADAR ESTIMATES HAVE REACHED 2-3" IN SPOTS...WITH BIG FLUFFY FLAKES FALLING HERE AT THE OFFICE INDICATING 20:1 RATIOS LOOK GOOD. WINDS AMPLE TO BLOW THIS SNOW AROUND AS WELL. EXPECT 2-4 OVER THE NEXT FEW HOURS AS BAND STARTS TO EDGE EAST FROM ITS CURRENT LOCATION...BEFORE LIKELY BREAKING UP BY LATE MORNING. NO OTHER CHANGES ATTM. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 422 AM EDT MON APR 1 2013 HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WIND GUSTS POSSIBLE ALL MARINE WATERS THROUGH TODAY. SNOW/BLOWING SNOW WILL BRING SOME SLICK TRAVEL AND REDUCED VISIBILITIES TO THE SNOWBELTS OF EASTERN UPPER/NORTHERN LOWER...WITH SNOW SHOWERS REACHING ALL OTHER LOCALES AS WELL. OVERVIEW: WISHING THE EARLY MORNING WATER VAPOR IMAGERY WAS AN APRIL FOOLS JOKE THIS MORNING AS IMPRESSIVE TROUGH CARVES ITSELF OUT OVER THE GREAT LAKES REGION. PICKLE LAKE /ONTARIO/ 00Z RAOB SHOWS -42C AT H5...-25C AT H7 AND -20C AT H8...AN ARCTIC AIRMASS INDEED WITH SURFACE TEMPS UPSTREAM OF THE GREAT LAKES IN THE LOWER TEENS AND DEWPOINTS FALLING TO NEAR ZERO. WITH SUBSTANTIAL DOWNSTREAM BLOCKING IN PLACE FROM GREENLAND SOUTH AND EAST...THE DEVELOPING LONGWAVE TROUGH OVERHEAD WILL BE IN NO HURRY TO DEPART...WITH ITS IMPACTS DOMINATING THE SHORT TERM PORTION OF THE FORECAST. THROUGH DAYBREAK: APX WSR-88D SHOWING LAKE EFFECT SNOW GETTING IT/S ACT TOGETHER OVER NORTHERN LOWER...WITH PRIMARY BAND FROM ACB-GOV STRENGTHENING WITH GOOD LAKE SUPERIOR CONNECTION. EXPECT THIS TREND TO CONTINUE THROUGH DAYBREAK WITH AN INCH OR TWO OF SNOW POSSIBLE OVER THE BIG 5 OF NW LOWER. WILL COVER THIS BAND WITH AN SPS FOR A QUICK 1-2 INCHES WHICH WILL LIKELY IMPACT THE MONDAY MORNING COMMUTE. WINDS REMAIN QUITE BRISK AS 6MB/6HR PRESSURE RISE CENTER OVER NORTHERN LAKE SUPERIOR SLIDES SOUTH AND EAST...WITH 15-25 MPH WINDS THROUGHOUT NORTHERN MICHIGAN...GUSTING AS HIGH AS 35 MPH NEAR THE COASTS. TODAY: WITH THE CORE OF THE H5 LOW PUSHING FROM JUST NORTH OF THE SOO EARLY THIS MORNING TO SOUTHWESTERN QUEBEC BY THSI EVENING...OUR FLOW ALOFT WILL BACK SLIGHTLY AS THE COLDEST AIR ALOFT MAKES ITS CLOSEST APPROACH. T8 AROUND -17C WITH WHAT LOOKS TO BE ROBUST LLEVEL MOISTURE /SEE FOG PRODUCT IMAGERY SHOWING ALL KINDS OF MOISTURE JUST WEST OF THE H5 LOW CENTER /AND THUS...OVERHEAD TODAY/. THIS SPELLS CONTINUED LAKE EFFECT SNOW SHOWERS UNDER STRONG NW WINDS. ALL HIGH RESOLUTION GUIDANCE CONTINUES TO SHOW A DOMINANT BAND TO START THE DAY...WITH THE HRRR LOOKING TO CAPTURE IT/S LOCATION BEST /FURTHER WEST THAN THE RAP AND LOCAL WRF/. GIVEN THAT WE ALREADY HAVE A BAND OF THIS NATURE...SEE NO REASON TO DISAGREE WITH THE GUDIANCE SUGGESTION...WHICH SHOWS THIS BAND STARTING THE DAY CENTERED FROM CVX-ACB-GOV PUSHING EAST GIVEN THE AFOREMENTIONED BACKING FLOW...WITH SOMEWHAT LIGHTER SHSN SURROUNDING IT. THE BAND LOOKS TO BE QUITE MOBILE THROUGH THE MORNING BEFORE CAPE/SHEAR NOMOGRAM SUGGESTS THAT BY LATE MORNING IT WIL BEGIN TO BREAK UP AS OVERLAND INSTABILITY STRENGTHENS. THIS BACKING FLOW SHOULD HELP GET WESTERN CHIPPEWA/MACKINAC BACK INTO THE ACTION DURING THE DAY AS WELL. SNOWFALL: MOBILE SNOWBAND WILL KEEP A LID ON SNOW AMOUNTS...BUT COULD SEE 1-3" FOR THE DAY TODAY OVER THE NW SNOWBELTS...WITH MOST OF THIS FALLING BEFORE ACTIVITY BECOMES MORE CELLULAR THIS AFTERNOON. WHILE WE LOSE HELP FROM ANY ISALLOBARIC COMPONENT TO THE LLEVEL WINDS TODAY...H9 WINDS 25-30KTS AND AMPLE LLEVEL MIXING SUGGEST WINDS 15-25 MPH WINDS WITH GUSTS WELL INTO THE 30S...PARTICULARLY NEAR THE LAKESHORES AND OVER EASTERN UPPER. TEMPS WILL BE VERY SLOW TO CLIMB WITH T9 AROUND -10C SUGGESTING MID 20S /SOME 20F BELOW NORMAL/ WILL BE ABOUT ALL WE CAN MUSTER. WITH THE STRONG WINDS...WIND CHILLS WILL REMAIN IN THE TEENS THROUGH THE DAY. HEADLINES: WILL GO AHEAD AND DROP WINTER WEATHER ADVISORY FOR CHIPPEWA GIVEN LOCATION OF SNOWFALL ACTIVITY WELL WEST OF COUNTY WITH ACCUMS THUS FAR NOT SUFFICIENT TO WARRANT THE HEADLINE. AS DISCUSSED ABOVE...HEAVIEST SNOW IS NOW OVER THE BIG 5 IN NW LOWER...AND WILL MONITOR FOR POTENTIAL HEADLINE THROUGH DAYBREAK...ALTHOUGH EXPECTATION IS THAT THE BAND WILL BEGIN TO MOVE...REDUCING THE THREAT OF SIGNIFICANT ACCUMS. TONIGHT: SYNOPTIC MOISTURE BEGINS TO SLOWLY ERODE WITH TEMPS ALOFT STEADY OR JUST SLIGHTLY WARING UNDER A FAIRLY STEADY 300-310 FLOW REGIME. SOME RESIDUAL LAND-BASED CAPE CONTINUES THROUGH THE OVERNIGHT WHICH MAY NOT FULLY ALLOW THE LAKE EFFECT TO RE-SOLIDIFY INTO BANDS. SHSN WILL CERTAINLY CONTINUE...HOWEVER...WITH ADDITIONAL LIGHT ACCUMULATIONS LIKELY. INHERITED ACCUMS OF 1-2 INCHES /PERHAPS 3 OVER WESTERN CHIPPEWA/ LOOK REASONABLE AND HAVE NO COMPELLING REASON TO DEVIATE SIGNIFICANTLY. CLOUDS WILL LIKELY KEEP TEMPERATURES FROM FALLING ALL THAT FAR... GENERALLY IN THE UPPER TEENS TO AROUND 20. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 422 AM EDT MON APR 1 2013 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. THE MOISTURE IN THE 850-700 MB LAYER FALLS OFF TO BELOW 60% ON ALL THE MODELS SO WOULD EXPECT LIGHT SNOW AND FLURRIES. ALTHOUGH WILL HAVE LIKELY POPS SINCE MEASURABLE SNOW IS EXPECTED FROM THIS PATTERN IN THE MORNING. BY THE AFTERNOON, THE MOISTURE CONTINUES TO FALL OFF IN THE 850-700 MB LAYER. THE ONE THING THAT I HAVE NOTICED ABOUT THESE LATE SEASON LES EVENTS IS THAT IT HAS BECOME HARD FOR THE LOWER END OF THE SOUNDINGS TO SATURATE. THIS HAS BEEN LEADING TO INVERTED V SOUNDINGS AND REALIZING LESS SNOW THAN WE WOULD HAVE EVEN A MONTH AGO DURING THE AFTERNOON. TUESDAY NIGHT...AS THE RIDGE BUILDS INTO THE REGION, THE DRIER AIR REALLY BEGINS TO OVERWHELM THE REGION, SHUTTING OFF MOST OF THE SNOW LEAVING ONLY CHANCE POPS IN THE EVENING IN E UPPER, WHILE N LOWER WILL BE DRY ENOUGH TO NOT HAVE ANY SNOW. WEDNESDAY...HIGH PRESSURE AT THE SFC AND 500 MB RIDGE MOVES THROUGH THE REGION SO THAT WE WILL REMAIN DRY FOR THE DAY. OVERNIGHT, A COLD FRONT AND 500 MB SHORTWAVE TROUGH MOVE INTO THE REGION. THE GFS IS A LITTLE FASTER THAN THE ECMWF AND NAM. WILL HOLD OFF THE SNOW BY ALLOWING IT TO JUST TOUCH E UPPER BY 12Z. EXTENDED (THURSDAY THROUGH SUNDAY)...THURSDAY, THE MODELS DRY THINGS OUT WITH THE FRONTAL PASSAGE DURING THE DAY. SO WILL HAVE CHANCE POPS WITH A MIX OF THE RAIN AND SNOW IN E UPPER AND JUST RAIN IN N LOWER. WITH THE SFC TEMPERATURES IN THE 40S, WOULD NOT BE SURPRISED IF THIS TURNS OUT TO BE FLURRIES AND SPRINKLES. FRIDAY, THE HIGH BUILDS INTO THE UPPER GREAT LAKES REGION AND DRIES THINGS OUT AGAIN. SO DRY WEATHER WILL BE EXPECTED. SATURDAY, THE WARM FRONT WILL BE MOVING INTO THE REGION. THE ECMWF HAS THE WARM AIR INTO E UPPER SO THAT IT COULD BE ALL RAIN, WHILE THE GFS HAS IT PLACED A LITTLE SOUTH. PUT THE DIVIDING LINE AT THE STRAITS SINCE THAT SEEMED TO BE THE MIDDLE GROUND. WHICH WOULD CONTINUE THROUGH THE NIGHT AS THE SYSTEM MOVES EAST. SUNDAY, THE LOW MOVES EAST OF THE REGION AND THE COLD AIR MOVES BACK IN ALLOWING FOR A CHANGE OVER TO SNOW. THE GFS DRIES THINGS OUT. WILL LEAN TOWARD THE ECMWF WHICH WOULD BE THE PESSIMISTIC FORECAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 153 PM EDT MON APR 1 2013 MVFR CIGS WILL CONTINUE OVR NRN MI THRU THE TAF PERIOD...A RESULT OF COLD NORTHWEST FLOW ON THE BACKSIDE OF A SYSTEM WOBBLING OVER QUEBEC. 850MB TEMPS WILL BE COLD ENOUGH TO GENERATE LAKE SNOWS OVER NRN MI TAF SITES INTO TUESDAY AFTN. THE MOST PERSISTENT LAKE SNOWS AND OCCASIONAL IFR VSBYS...WILL INFLUENCE TAF SITES KPLN AND KTVC INTO TUESDAY AFTN. && .MARINE... ISSUED AT 422 AM EDT MON APR 1 2013 UPDATE AT 708 AM...DROPPED GALE WARNINGS FOR ALL AREAS SAVE WHITEFISH BAY AND THE COAST OF NORTHERN LAKE HURON. HIGH END SMALL CRAFTS SHOULD SUFFICE THROUGH TODAY AND WILL NEED EXTENDING BEYOND TONIGHT IN SUBSEQUENT UPDATES. SUMMARY: STRONG NORTHWESTERLY WINDS TO CONTINUE THROUGH TUESDAY AS LOW PRESSURE MOVES INTO EASTERN CANADA. HIGH PRESSURE ARRIVES BY MIDWEEK WITH QUIETER CONDITIONS EXPECTED. HEADLINES: MARGINAL GALES WILL BE ALLOWED TO CONTINUE ALL ZONES THROUGH THIS EVENING. SMALL CRAFTS WILL CERTAINLY BE NEEDED BEYOND THIS...WITH ADDITIONAL GALE FORCE GUSTS POSSIBLE AGAIN TUESDAY...PARTICULARLY FOR NORTHWESTERLY FLOW FAVORED REGIONS. BEYOND THIS...NEXT ROUND OF SMALL CRAFTS LOOKS LIKELY BY WEDNESDAY NIGHT OVER LAKE MICHIGAN AS SOUTHWESTERLY WINDS STRENGTHEN AHEAD OF NEXT APPROACHING SYSTEM. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR MIZ015>017-019-021>023-027-028. LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345-346- 349. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LHZ347-348. LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-341- 342-344>346. LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ322. GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ321. && $$ UPDATE...SR SYNOPSIS...JL SHORT TERM...ARNOTT LONG TERM...JL AVIATION...SR MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
126 PM EDT MON APR 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 440 AM EDT MON APR 1 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF CENTERED FM HUDSON BAY INTO THE GRT LKS DOWNSTREAM OF UPR RDG OVER WRN CANADA. 00Z H5/H85 TEMPS ARE AS LO AS -42C/-20C AT THE CORE OF THE COLDEST AIR AT YPL. CYC NNW FLOW ON THE WRN FLANK OF LO PRES MOVING SLOWLY E INTO QUEBEC IS DRAWING THIS VERY COLD AIR SWD INTO THE UPR LKS OVER THE RELATIVELY WARM WATERS OF LAKE SUP...WITH THE RESULT NMRS LES BANDS AS SHOWN ON MQT RADAR. WELL DEFINED AXIS OF COLDER CLD TOPS AS SHOWN ON IR STLT IMAGERY IS PRESENT OVER THE E HALF OF THE LK AND ASSOCIATED WITH FAIRLY SHARP H7-3 QVECTOR CNVGC. THIS AXIS OF DEEPER MSTR HAS CAUSED SOME ENHANCEMENT TO THE SHSN. THE HEAVIEST BAND IS STREAMING INTO CENTRAL ALGER COUNTY/SCHOOLCRAFT COUTY...WITH SOME RETURNS AOA 30 DBZ AT 06Z. SN UNDER THIS BAND IS LIKELY FALLING AT THE RATE OF AT LEAST AN INCH/HR GIVEN FAVORABLE LOCATION OF UVV MAX WITHIN DGZ AS SHOWN BY PROFILE FM LOCAL HI RES MODEL. SINCE THE COLDER CLD TOPS ARE TENDING TO DRIFT TO THE E AND DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB IS PRESSING TO THE E... DROPPING THE SFC DEWPT TO NEAR 7F AT IWD AT 06Z...THE INTENSITY OF THE LES W OF MQT HAS TENDED TO DIMINISH OVER TIME PER RADAR TRENDS EVEN THOUGH IR STLT IMAGERY INDICATES SOME LES BANDS OVER THE W HALF OF THE LK THAT HAVE FORMED IN THE PRESENCE OF NOCTURNAL COOLING THAT IS SO IMPORTANT TO ACHIEVE BETTER LES BAND STRUCTURE THIS TIME OF YEAR. NW WINDS ARE STILL GUSTING AS HI AS 40 KTS AT STANNARD ROCK AS OF 06Z...BUT PASSAGE OF PRES RISE CENTER TRAILING THE SFC LO INTO ONTARIO E OF LK SUP HAS CAUSED A SLOW DIMINISHING TREND TO THE WINDS. MAIN FCST CONCERNS THIS PACKAGE ARE LES TRENDS/GOIND HEADLINES. TODAY...MODELS INDICATE UPR TROF AXIS WL DRIFT SLOWLY TO THE E. AREA OF DEEP LYR QVECTOR CNVGC ENHANCING COMMA HEAD/COLDER CLD TOPS NOW OVER THE E HALF OF LK SUP IS PROGGED TO DRIFT INTO ONTARIO IN THE 09Z-12Z TIME FRAME. IN CONCERT WITH THE ARRIVAL OF SOME DRYING FM THE W...LES INTENSITY/COVERAGE SHUD DIMINISH BY SUNRISE. BUT GIVEN PERSISTENCE OF SGNFT BAND OVER CENTRAL ALGER COUNTY INTO NRN SCHOOLCRAFT COUNTY IN PERSISTENT NNW FLOW THRU THE EARLY MRNG HRS...FVRBL SN/WATER RATIOS UNDER COLDEST H85 TEMPS...AND HIER RES MODEL FCSTS THAT SHOWING FAIRLY HI QPF THRU 18Z WITH DEEPER MSTR PERSISTING LONGEST IN THAT AREA CLOSER TO DEPARTING LO...OPTED TO UPGRADE GOING ADVY FOR THOSE ZONES TO AN LES WARNING. OTRW...RISING H5 HGTS/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE PRESENCE OF DIURNAL HEATING THAT TENDS TO DISRUPT THE LES PROCESS IN EARLY SPRING SHOULD CAUSE THE LES BANDS TO WEAKEN AND TRANSITION TO A MORE BLOTCHY APPEARANCE. SLOWLY BACKING FLOW TOWARD MORE WNW BY THE LATE IN THE DAY WL ALSO CAUSE AREA OF HEAVIER SHSN TO SHIFT. ADDITIONAL SN AMOUNTS OVER THE W WL BE LIGHT WITH LLVL DRY AIR HAVING A MORE SGNFT IMPACT THERE AND MODELS HINTING TOWARD A TRANSITION TO LLVL ACYC FLOW IN THE AFTN. TONIGHT...STEADILY RISING HGTS/DEEP LYR QVECTOR CNVGC THAT DROPS FCST INVRN BASE TOWARD 5-6K FT OVER EVEN THE E SUG LES INTENSITY WL BE SOMEWHAT DIMINISHED EVEN THOUGH PERSISTENT NW FLOW/H85 TEMPS IN THE -16 TO -17C RANGE WL ALLOW FOR CONTINUED WDSPRD LES...ESPECIALLY AFTER MID EVNG WHEN IMPACTS OF DAYTIME HEATING WOULD TEND TO SUBSIDE. WITH INVRN BASE OVER THE W FALLING TO ARND 4K FT OVER THE W...SHSN INTENSITY IN THIS AREA WL BE WEAKER WITH SHORTER FETCH/LESS MODERATION OF UPSTREAM AIRMASS. BUT STILL WENT WITH LIKELY POPS GIVEN FVRBL NW FLOW/OVERWATER INSTABILITY/NOCTURNAL COOLING THAT WL ALLOW LES BANDS TO REDEVELOP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 440 AM EDT MON APR 1 2013 DESPITE ADEQUATE DELTA TS PERSISTING INTO TUESDAY FOR LAKE EFFECT...SFC-H85 FLOW WILL BECOME INCREASINGLY ANTICYCLONIC THROUGH THE DAY. IN ADDITION...INVERSION HEIGHTS BEGIN TO FALL OFF SIGNIFICANTLY BELOW 5KFT. THUS...EXPECT OVERALL COVERAGE AND INTENSITY OF LAKE EFFECT TO BE ON THE WANE AS THE DAY PROGRESSES. TEMPERATURES WILL REMAIN WELL BELOW NORMAL WITH A SIGNIFICANT AMOUNT OF CLOUDINESS DOWNWIND OF LAKE SUPERIOR. LAKE CLOUDS AND EVEN A FEW FLURRIES WILL PERSIST INTO THE MORNING WEDNESDAY OVER THE EAST. AS SURFACE RIDGE AXIS MOVES OVERHEAD THROUGH THE DAY EXPECT SKIES TO BECOME MOSTLY SUNNY AREA WIDE. TEMPERATURES SHOULD REBOUND BACK ABOVE FREEZING AND EVEN APPROACH 40 ACROSS THE WEST WITH WARM ADVECTION INCREASING DURING THE AFTERNOON AND MORE SUNSHINE. MODELS COMING INTO BETTER AGREEMENT WITH THE TIMING OF THE NEXT SHORTWAVE AND SFC TROUGH EXPECTED TO MOVE ACROSS THE AREA WED NIGHT/THU. THE TREND HAS BEEN TOWARD QUICKER MOVEMENT WITH THE TROUGH. SYSTEM IS FAIRLY MOISTURE STARVED...SO DESPITE PRECIP TYPE BEING A CHALLENGE BETWEEN RAIN AND SNOW...AMOUNTS WILL BE LIGHT ENOUGH TO BE PRETTY INSIGNIFICANT. COLD ADVECTION BEHIND THE TROUGH SHOULD PUSH 85H TEMPS BACK DOWN TO THE -10 TO -14C RANGE BY FRIDAY. PROBABLY NOT QUITE COLD ENOUGH FOR LAKE EFFECT THIS TIME AROUND...BUT COLDER AIR WILL KEEP DAYTIME TEMPS BELOW AVERAGE ONLY IN THE 30S. FORECAST FOR NEXT WEEKEND STILL PRETTY CHALLENGING...BUT MODELS SHOWING SOME SIGNS THAT THEY ARE TRYING TO CONVERGE ON A MORE PROBABLE OUTCOME. SHORTWAVE ENERGY AND ASSOCIATED SURFACE LOW MOVING OUT OF THE PLAINS LOOKING LIKE THEY MAY NOW TRACK THROUGH THE LOWER LAKES WHICH WOULD STILL RESULT IN SOME LIGHT SNOWFALL ACROSS SOUTHERN AREAS SATURDAY INTO SUNDAY BUT SPARE THE AREA FROM A MORE SIGNIFICANT STORM. IT IS STILL SOMETHING TO KEEP AN EYE ON AS WE HEAD THROUGH THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 125 PM EDT MON APR 1 2013 DRY AIR MOVING ACROSS LAKE SUPERIOR SHOULD HELP TO KEEP CMX AND IWD AT OR ABOVE MVFR THROUGH THE TAF PERIOD. CEILINGS SHOULD REMAIN AT OR ABOVE 3KFT FOR EACH TAF SITE...WITH KSAW POSSIBLY REACHING VFR CEILINGS THIS AFTERNOON AND EVENING AS WNW WINDS ALLOW FOR DOWNSLOPING OVER THAT AREA. VISIBILITIES ARE A BIT TRICKY AS INTERMITTENT SNOW SHOWERS PASS OVER EACH TAF SITE...OCCASIONALLY REDUCING VISIBILITY TO MVFR OR LOWER AT TIMES...ESPECIALLY OVER THE KEWEENAW WHERE WINDS MAY REMAIN GUSTY THROUGH THE TAF PERIOD INCREASING THE POTENTIAL FOR BLOWING SNOW. WINDS ARE EXPECTED TO DECREASE OVER THE REMAINING TAF SITES AS PRESSURE GRADIENT IS REDUCED AS THE SURFACE LOW SHIFTS TO CENTRAL QUEBEC BY TUESDAY MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 440 AM EDT MON APR 1 2013 AS LO PRES OVER SE CANADA CONTINUES TO THE E AND THE PRES GRADIENT WEAKENS...EXPECT NW WINDS TO SLOWLY DIMINISH AND BELOW GALE FORCE OVER THE CENTRAL BY MID MORNING...SO HASTENED THE ENDING OF THE GALE WARNINGS FOR THIS AREA. ALTHOUG NW GALES TO 35 KTS WILL CONTINUE LONGER OVER THE E INTO THIS EVENING...ENDED THE GALES FOR THAT AREA EARLIER AS WELL. WINDS/WAVES WILL BE SUFFICIENT TO MAINTAIN FREEZING SPRAY OVER AT LEAST THE E HALF THRU TONIGHT. WINDS WILL REMAIN PRETTY GUSTY UP TO 30 KNOTS OVER THE EASTERN LAKE THROUGH THE DAY ON TUESDAY...BUT AS SURFACE RIDGE AXIS PUSHES IN FROM THE WEST PRESSURE GRADIENT WILL RELAX AND WINDS WILL DIMINISH DURING THE EVENING. UNTIL THAT TIME...FREEZING SPRAY SHOULD CONTINUE ACROSS THE EASTERN LAKE. AFTER A BRIEF RESPITE ON WEDNESDAY...SOUTHWESTERLY WINDS UP TO 25 KNOTS AHEAD OF THE NEXT TROUGH CROSSING THE LAKE WILL INCREASE WEDNESDAY NIGHT INTO EARLY THURSDAY BEFORE SHIFTING TO THE NORTHWEST DURING THE DAY THURSDAY INTO THURSDAY NIGHT. WINDS FOR FRIDAY INTO NEXT WEEKEND SHOULD BE BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-085. WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ007. LAKE SUPERIOR... GALE WARNING UNTIL 2 AM EDT TUESDAY FOR LSZ250-251-266-267. GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...MZ AVIATION...KEC MARINE...KC/MZ
AREA FORECAST DISCUSSION
NWS BISMARCK ND
547 PM CDT MON APR 1 2013 .UPDATE... ISSUED AT 546 PM CDT MON APR 1 2013 LATEST SUITE OF SATELLITE IMAGERY/SURFACE OBSERVATIONS SHOWS CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH THE EXCEPTION OF A SCT/BKN CUMULUS DECK OVER THE HIGHER TERRAIN IN THE SOUTHWEST...IN CONJUNCTION WITH A LOW LEVEL BAROCLINIC ZONE. TEMPERATURES WERE IN THE 50S ACROSS SOUTHEAST MONTANA...WITH TEMPERATURES AROUND 40 IN OUR SOUTHWEST ZONES. OTHERWISE...A 1030MB SURFACE HIGH PRESSURE SITS OVER NORTHERN NORTH DAKOTA THIS EVENING PRODUCING CLEAR SKIES AND LIGHT WINDS. FURTHER UPSTREAM...WATER VAPOR IMAGERY SHOWS A WEAK SHORTWAVE TROUGH ALOFT OVER NORTHEAST SASKATCHEWAN ALONG WITH A SURFACE REFLECTION/SURFACE TROUGH PER MSAS...ALL MOVING SOUTHEAST WITH TIME. THIS SHORTWAVE IS FORECAST TO MOVE TO LAKE WINNIPEG BY 06Z TUESDAY...THEN INTO NORTHERN MINNESOTA BY 12Z TUESDAY. BEST UPWARD VERTICAL MOTION/H85-H3 OMEGA FIELD IS FORECAST OVER SOUTHERN MANITOBA DURING THE 06Z-12Z TUESDAY TIME FRAME. HOWEVER THE 18Z NAM/GFS AND LATEST RAP MODEL PRODUCE A SWATH OF 80 TO 90 PERCENT H85-H7 RH LATER TONIGHT ASSOCIATED WITH THIS SHORTWAVE. THE NAM/GFS ALSO PAINT LIGHT QPF OF 0.01 COVERING PORTIONS OF BOTTINEAU AND ROLETTE COUNTIES BETWEEN 09Z AND 12Z TUESDAY. THE LATEST RAP MODEL KEEPS THE PRECIPITATION JUST EAST OF BOTTINEAU/ROLETTE COUNTIES. OBSERVATIONS AND PAST WEATHER IN LOCATION OF CURRENT SHORTWAVE DOES REVEAL A POCKET OF LOW/MID LEVEL CLOUDS AND A BRIEF PERIOD OF ISOLATED FLURRIES. FOR THIS UPDATE...HAVE COLLABORATED WITH NEIGHBORING OFFICES TO INCREASE THE SKY GRIDS FOR THE NORTHEAST TONIGHT...BUT HOLD OFF ON ANY MENTION OF PRECIPITATION AS BEST VERTICAL MOTION IS FORECAST NORTH/EAST. WILL AWAIT THE 00Z MODEL RUNS AND KEEP A CLOSE EYE ON THE RAP MODEL THIS EVENING FOR ANY CHANGES. UNTIL OBSERVATIONS SUGGEST SOMETHING DEVELOPING CLOSER TO OUR NORTHERN BORDER...WILL STAY THE COURSE WITH THE DRY FORECAST. REST OF FORECAST IS IN GOOD SHAPE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 346 PM CDT MON APR 1 2013 HIGH PRESSURE WILL GRADUALLY SHIFT EAST OF THE REGION THROUGH THE PERIOD. DRY CONDITIONS WILL PREVAIL AS A RESULT. BELOW NORMAL TEMPERATURES WILL CONTINUE THIS AFTERNOON AND TONIGHT. HOWEVER...RETURN FLOW DEVELOPING ACROSS THE REGION COMBINED WITH NO SNOW PACK SOUTHWEST OF THE MISSOURI WILL ALLOW TUESDAY AFTERNOON HIGHS TO BE ABOVE NORMAL SOUTHWEST. BELOW NORMAL TEMPERATURES WILL CONTINUE NORTH AND EAST OF THE MISSOURI RIVER...WHERE THE SNOW PACK IS LOCATED. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 346 PM CDT MON APR 1 2013 THE MAIN FORECAST CHALLENGES FOR THE EXTENDED PERIOD INCLUDE PRECIPITATION CHANCES AND PRECIPITATION TYPE. 12Z SUITE OF MODEL SOLUTIONS ARE IN AGREEMENT EARLY IN THE PERIOD...WITH SOLUTIONS DIVERGING LATE THIS WEEK. WARM AIR ADVECTION WILL CONTINUE ACROSS THE AREA TUESDAY NIGHT AND WEDNESDAY AHEAD OF A UPPER LEVEL WAVE/SURFACE LOW PRESSURE SYSTEM THAT IS FORECAST TO PASS OVER NORTH DAKOTA. WARM H850 TEMPERATURES OF +6 TO +10C WILL BE FIRMLY IN PLACE WEDNESDAY AS PRECIPITATION BEGINS ACROSS THE NORTHWEST AND SPREADS SOUTHEAST ACROSS THE AREA WEDNESDAY. PRECIPITATION WILL BEGIN AS LIGHT FREEZING RAIN AND TRANSITION TO LIGHT RAIN DURING WEDNESDAY AFTERNOON. ACROSS THE SOUTHWEST...ISOLATED WEAK THUNDERSTORMS ARE POSSIBLE...WHERE TEMPERATURES WILL BE IN THE 60S WITH SURFACE BASED CAPE IN THE 100 TO 200 J/KG ADVERTISED BY THE 12Z NAM. BEFORE ENDING WEDNESDAY EVENING...A TRANSITION FROM LIGHT RAIN TO A WINTRY MIX OF SNOW...FREEZING RAIN...AND POSSIBLY SLEET WILL BE SEEN AS A COLD FRONT MOVES SOUTH FROM CANADA. COOLER TEMPERATURES WILL BE SEEN WEDNESDAY NIGHT AND THURSDAY...AS COLD AIR COMMENCES FOLLOWING THE PASSAGE OF THE AFOREMENTIONED COLD FRONT. HOWEVER...ACROSS THE SNOW LESS AREAS...TEMPERATURES WILL BE WARMEST WITH TEMPERATURES IN 50S ON THURSDAY. FOR LOCATIONS ACROSS THE SNOWPACK...TEMPERATURES WILL BE IN THE LOW TO MID 30S. STARTING FRIDAY...AN ACTIVE PERIOD OF WEATHER IS EXPECTED TO START AS A SERIES OF UPPER LEVEL WAVES AND THEIR SURFACE REFLECTIONS ARE PROGGED TO MOVE ACROSS THE AREA IN NORTHWESTERLY FLOW. UNCERTAINTY REMAINS IN THE PLACEMENT AND TYPE OF PRECIPITATION ACROSS NORTH DAKOTA...AS THERE IS DISAGREEMENT AMONGST THE 12Z MODEL SOLUTIONS. THE 12Z GEM/GFS ARE MORE AGGRESSIVE WITH QPF ACROSS THE WEST AND CENTRAL VERSUS THE 12Z EC SOLUTION. THE 12Z EC KEEPS THE BULK OF THE PRECIPITATION FURTHER NORTH ACROSS SOUTHERN MANITOBA AND SASKATCHEWAN. AT THIS TIME HAVE UTILIZED A BLEND OF MODEL SOLUTIONS DURING THE FRIDAY TO MONDAY PERIOD...WHICH GIVE A WIDE ARRAY OF PRECIPITATION TYPES. AT THIS MOMENT...IT LOOKS LIKE THE SOUTHWEST WILL REMAIN MOSTLY RAIN AS IT REMAINS IN THE WARM H850 TEMPERATURES OF +4 TO +8 C. ELSEWHERE...A LIGHT WINTRY MIX OF SNOW...FREEZING RAIN...AND POSSIBLY SLEET MAY OCCUR. BY SUNDAY EVENING AND MONDAY...PRECIPITATION TYPE WILL BE SNOW...AS ANOTHER COLD FRONT DROPS SOUTH OUT OF CANADA. FOLLOWING THE PASSAGE OF THE COLD FRONT...COLDER H850 TEMPERATURES OF -8 TO -12 C ARE POSSIBLE AT THE BEGINNING OF NEXT WEEK...AS A SURFACE HIGH PRESSURE STARTS TO MOVE SOUTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING... ISSUED AT 546 PM CDT MON APR 1 2013 GENERALLY CLEAR SKIES/VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE 00Z TAF PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...TM LONG TERM...LTH AVIATION...KS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1113 AM MDT MON APR 1 2013 .UPDATE... ISSUED AT 1047 AM MDT MON APR 1 2013 CURRENT SURFACE ANALYSIS SHOWS CANADIAN HIGH PRESSURE OVER EASTERN PORTIONS OF THE DAKOTAS. UPPER LEVEL ANALYSIS SHOWS LARGE TROF CENTERED OVER THE GREAT LAKES REGION...WITH RIDGING OVER THE PACIFIC NW. A CUTOFF LOW IS SLOWLY MOVING EAST-SOUTHEAST ACROSS NV. SKIES CURRENTLY RANGE FROM SUNNY ACROSS NORTHEAST WY AND SOUTHWESTERN SD TO PARTLY TO MOSTLY CLOUDY FROM NORTHWESTERN INTO CENTRAL SD. BAND OF CLOUDS IS SLOWLY DISSIPATING ACROSS THESE AREAS...WITH MOSTLY SUNNY SKIES EXPECTED BY EARLY AFTERNOON. NEAR TO SLIGHTLY BELOW AVERAGE TEMPERATURES CAN BE EXPECTED THIS AFTERNOON...WITH HIGHS IN THE MID 40S TO MID 50S...WARMEST OVER NORTHEASTERN WY AND COOLEST OVER FAR EASTERN AREAS. WINDS WILL REMAIN RELATIVELY LIGHT AND VARIABLE THROUGH THE AFTERNOON. MAIN ADJUSTMENTS TO THE FORECAST WERE TO TWEAK CLOUD COVER AND WINDS FOR THE REST OF TODAY. && .SHORT TERM...TODAY THROUGH TUESDAY NIGHT ISSUED AT 240 AM MDT MON APR 1 2013 ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME. THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S. RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR SOME PASSING CIRRUS. TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH. .LONG TERM...WEDNESDAY THROUGH SUNDAY ISSUED AT 240 AM MDT MON APR 1 2013 UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1109 AM MDT MON APR 1 2013 LEFTOVER MARGINALLY MVFR CIGS FROM KPHP TO KVTN WILL MOVE SLOWLY EAST AND DISSIPATE EARLY THIS AFTERNOON AS BOUNDARY LAYER MIXES OUT. SOME VFR CU IS EXPECTED FROM K2WX TO KVTN FOR THE AFTERNOON. OTHERWISE...VFR CONDITIONS WILL BE THE RULE THROUGH THE PERIOD. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...26 SHORT TERM...JC LONG TERM...15 AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1047 AM MDT MON APR 1 2013 .UPDATE... ISSUED AT 1047 AM MDT MON APR 1 2013 CURRENT SURFACE ANALYSIS SHOWS CANADIAN HIGH PRESSURE OVER EASTERN PORTIONS OF THE DAKOTAS. UPPER LEVEL ANALYSIS SHOWS LARGE TROF CENTERED OVER THE GREAT LAKES REGION...WITH RIDGING OVER THE PACIFIC NW. A CUTOFF LOW IS SLOWLY MOVING EAST-SOUTHEAST ACROSS NV. SKIES CURRENTLY RANGE FROM SUNNY ACROSS NORTHEAST WY AND SOUTHWESTERN SD TO PARTLY TO MOSTLY CLOUDY FROM NORTHWESTERN INTO CENTRAL SD. BAND OF CLOUDS IS SLOWLY DISSIPATING ACROSS THESE AREAS...WITH MOSTLY SUNNY SKIES EXPECTED BY EARLY AFTERNOON. NEAR TO SLIGHTLY BELOW AVERAGE TEMPERATURES CAN BE EXPECTED THIS AFTERNOON...WITH HIGHS IN THE MID 40S TO MID 50S...WARMEST OVER NORTHEASTERN WY AND COOLEST OVER FAR EASTERN AREAS. WINDS WILL REMAIN RELATIVELY LIGHT AND VARIABLE THROUGH THE AFTERNOON. MAIN ADJUSTMENTS TO THE FORECAST WERE TO TWEAK CLOUD COVER AND WINDS FOR THE REST OF TODAY. && .SHORT TERM...TODAY THROUGH TUESDAY NIGHT ISSUED AT 240 AM MDT MON APR 1 2013 ACTIVE PROGRESSIVE NORTHERN STREAM FLOW WILL DOMINATE THE WEATHER IN THE PERIOD...WITH A LARGE SCALE SPLIT FLOW REGIME. THIS WILL OFFER WARM DOWNSLOPE PAC ORIGIN FLOW INTO THE AREA...ESP TUE. GREAT LAKES UPPER TROUGH WILL SLOWLY SHIFT EAST WITH DEEP LAYER RIDGING DEVELOPING TODAY...INITIATING WAA BY THIS AFTERNOON OVER THE WESTERN FA. THE ONLY FORECAST CONCERN TODAY WILL BE THE EVOLUTION OF THE CURRENT STRATUS IN PLACE ACROSS THE EASTERN FA...WHICH MAY HAMPER T RISES. THE ONLY FORECAST MODELS WHICH SEEMS TO HAVE ANY SORT OF HANDLE ON THE EXISTENCE OF CLOUD COVER IS THE RAP AND LOCAL WRF...WITH ALL OTHER GUIDANCE REMAINING TOO DRY IN THE LL/S. RAP/LOCAL WRF BOTH INDICATE THAT INCREASING DRY WESTERLY FLOW AT THE BL TOP SHOULD HELP ERODE CLOUD COVER WEST TO EAST THROUGH MORNING AND TRIED TO INCORPORATE THIS IDEA INTO THE GRIDS. ONCE CLOUDS CLEAR...SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD...SAVE FOR SOME PASSING CIRRUS. TEMPS WILL REMAIN ON THE COOL SIDE ACROSS MOST OF THE AREA TODAY...WITH THE SD PLAINS BEING THE COOLEST. NE WY WILL SEE QUICK RESPONSE TO ENSUING WAA WITH MANY PLACES EXPECTED TO BE IN THE 50S THERE. HAVE ADJUSTED TEMPS UP SOME...GIVEN LATEST BLENDED GUIDANCE WITH STRONG INSOLATION EXPECTED. MUCH WARMER CONDITIONS EXPECTED TUE...WITH 50S AND 60S COMMON MOST PLACES. HAVE WARMED MOST PLACES A FEW DEGREES TUE...ESP NE WY. STRONG INSOLATION SHOULD SUPPORT SUPERADIABATS AT MOST LOCATIONS GIVEN WEAK LL FLOW...WITH TEMPS WARMER THAN CURRENT FORECAST HIGHS CERTAINLY POSSIBLE. THE NEXT NORTHERN STREAM IMPULSE WILL APPROACH THE REGION TUE...WITH WAA RAMPING UP...AS WELL AS LL SOUTHERLY FLOW TUE NIGHT. THIS SHOULD KEEP TEMPS UP AT MANY PLACES OVERNIGHT TUE...GIVEN TURBULENT MIXING...ESP IN THE LEE DOWNSLOPE AREAS OF THE BH. .LONG TERM...WEDNESDAY THROUGH SUNDAY ISSUED AT 240 AM MDT MON APR 1 2013 UPPER LEVEL RIDGE FLATTENS LATE WEDNESDAY AS A COLD FRONT CROSSES THE AREA...BRINGING A CHANCE FOR RAIN SHOWERS AND AN ISOLATED THUNDERSTORM. RAIN SHOWERS WILL LINGER INTO THURSDAY...MAINLY ACROSS NORTHERN PORTIONS OF THE AREA. A MORE UNSETTLED PATTERN WILL DEVELOP BY THE WEEKEND AS A LARGE UPPER TROF DEVELOPS OVER THE WEST COAST AND A SERIES OF DISTURBANCES MOVE ACROSS THE NORTHERN PLAINS IN WEST TO SOUTHWEST FLOW. TEMPERATURES WILL GENERALLY STAY ABOVE AVERAGE LATE IN THE WEEK AND LIKELY DROP CLOSER TO AVERAGE LEVELS DURING THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 540 AM MDT MON APR 1 2013 MVFR CIGS WILL PERSIST ACROSS THE WESTERN SOUTH DAKOTA PLAINS THROUGH THE MORNING HOURS BEFORE LIFTING AND SHIFTING EAST BY 18Z. VFR CONDITIONS ARE THEN EXPECTED THROUGH TUESDAY MORNING. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...26 SHORT TERM...JC LONG TERM...15 AVIATION...15
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
329 PM CDT MON APR 1 2013 .SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...ANOTHER ONE OF THESE FORECASTS WHERE MESO-SCALE INFLUENCES MAY PLAY HAVOC ON WHAT TRANSPIRES TONIGHT. MAIN FLY IN OINTMENT NOW IS THAT LOTS OF STRATUS IS JUST ACROSS THE RIVER AND TEMPERATURES OUT WEST ARE NOT THAT WARM...SO SEA BREEZE LIMITED OUT THERE AS WELL AS DAYTIME HEATING. THUS...CONVERGING BOUNDARIES LIKE LAST NIGHT NOT PRESENT AND STORMS MAY HAVE A HARD TIME FIRING UP DIRECTLY WEST OF FORECAST AREA. HOWEVER...STORMS ARE DEVELOPING FARTHER NORTHWEST OF STRATUS DECK (HAVE A LONG WAY TO GO THOUGH). STILL AM GOING TO GO WITH LOW CHANCE POPS NEAR RIO GRANDE AND DIMINISH THEM FARTHER EAST. THING THAT HELPS CONVECTION TO DEVELOP IS EASTERLY UPSLOPE FLOW SO DO NOT WANT TO GO TOO LOW ON POPS (ESPECIALLY WITH SLIGHT RISK IN AREA)...AND WITH SPC 4 KM MODEL AND HRRR MODEL SHOWING ACTIVITY MOVING IN THERE. OTHERWISE...TEMPERATURES SHOULD BE SIMILAR TO LAST NIGHT...EXCEPT WHERE CONVECTION COULD COOL AIR SOME. NO SIGNIFICANT FOG EXPECTED. UPPER LEVEL JET IMPACTS AREA ON TUESDAY AS CAP BREAKS/WEAKENS. AM GOING HIGH CHANCE POPS EASTERN AREAS...TAD LOWER OUT WEST. MORE CLOUDS AND RAIN-COOLED AIR MEANS LOWER TEMPERATURES TUESDAY. SOME JET DYNAMICS REMAIN TUESDAY NIGHT AS FRONT APPROACHES...SO PRETTY MUCH HAVE KEPT POPS SIMILAR TO PREVIOUS FORECAST WITH SLIGHT ADJUSTMENT OF HIGHER POPS A BIT MORE TOWARD THE NORTHEAST (AREA ADJUSTEMENT...STILL NO MORE THAN 70 POPS). WITH COOLER AIR REMAINING NORTH OF AREA (BUT PROBABLY SOME CONVECTION AROUND COOLING THINGS OFF)...WILL GO A BIT COOLER TUESDAY NIGHT THAN TONIGHT. SPECIAL WEATHER STATEMENT HAS BEEN ISSUED TO HIGHLIGHT UPCOMING EVENT. && .MARINE (TONIGHT THROUGH TUESDAY NIGHT)...SEA FOG ALBEIT LIGHT REMAINS IN THE FORECAST AS VISIBLE SATELLITE AND OBSERVATIONS SHOW SOME OUT THERE. OVERALL VISIBILITIES SHOULD REMAIN ABOVE 2 NM. GENERALLY WEAK TO MODERATE ESE/SE FLOW THROUGH THE PERIOD. RAIN CHANCES INCREASE MAINLY LATE TUESDAY AND TUESDAY NIGHT. && .LONG TERM (WEDNESDAY THROUGH SUNDAY)...OVERALL TREND CONTINUES ABUNDANT GULF MOISTURE ACROSS THE REGION WITH PWATS 1.3 TO 1.5 INCHES...WHICH IS JUST OVER 75 PERCENT OF NORMAL PWATS FOR THIS TIME OF YEAR. TIMING OF THE FRONT STILL REMAINS A CHALLENGE ALTHOUGH MODEST AGREEMENT BETWEEN THE EURO/CANADIAN/NAM AROUND 00Z...WITH THE GFS LAGGING A FEW HOURS BEHIND. A PREFRONTAL WIND SHIFT SHOULD TAKE PLACE BETWEEN 18Z-00Z. WITH MULTIPLE SHORTWAVES ROUNDING THE SOUTHERN PERIPHERY OF THE MIDLEVEL LOW //POSITIONED OVER THE CENTRAL PLAINS//...CONTINUED HIGH END CHANCE TO LIKELY POPS GOING INTO WEDNESDAY...WITH MOST ACTIVITY IN THE MORNING BEING MORE OF A SHOWER ACTIVITY UNDER A WEAK CAP. HOWEVER...DID CONTINUE THUNDER WORDING AS A VORT MAX AND 60 KNOT JET MOVE OVER THE AREA. DID SHOW THE INCREASE IN CHANCES INTO THE AFTERNOON AS FURTHER COOLING IN THE MIDLEVELS TAKES PLACE WITH THE FRONT SLOWLY MOVING SOUTHWARD. CONCERN DOES EXIST IN THE AFTERNOON TO EARLY EVENING FOR STRONG TO SEVERE AS LAPSE RATES STEEPEN WITH LI VALUES OF -7C TO -9C. HOWEVER...THE ONSHORE IS WEAK TO FEED INTO ANY STORMS. CURRENTLY IF ANYTHING DEVELOPS INTO THE STRONG TO SEVERE CATEGORY...SHOULD BE MORE OF PULSE STORMS...WITH BETTER CHANCES ALONG THE FRONT ITSELF. WILL CONTINUE TO MONITOR THE DEVELOPMENT OF THIS WEATHER EVENT. MOISTURE AND THE MIDLEVEL LOW PULLS TO THE NORTHEAST WITH DRYING FROM WEST TO EAST LATE WEDNESDAY INTO THURSDAY WITH HIGH PRESSURE ENTERING THE REGION. QUIET WEATHER TO PERSIST INTO THE WEEKEND WITH A ONSHORE FLOW DEVELOPING SATURDAY. TEMPERATURES TO COOL INTO THE 70S AREAWIDE THURSDAY...WITH A WARMING TREND INTO THE WEEKEND UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 68 82 69 81 55 / 10 50 50 70 40 VICTORIA 66 80 66 76 52 / 10 50 70 70 40 LAREDO 67 86 70 83 58 / 40 30 30 40 10 ALICE 68 86 69 83 55 / 10 50 50 60 30 ROCKPORT 68 77 68 75 55 / 10 50 60 70 40 COTULLA 65 83 67 78 53 / 30 30 50 50 10 KINGSVILLE 67 84 69 82 55 / 10 50 40 60 40 NAVY CORPUS 68 78 69 76 58 / 10 50 50 70 40 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ GW/86...SHORT TERM CB/85...LONG TERM
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
208 PM CDT MON APR 1 2013 .SHORT TERM /NOW THROUGH TUESDAY NIGHT/...THE AREA REMAINS IN QUASI-ZONAL FLOW ALOFT WITH AN UPPER LEVEL TROUGH LOCATED OVER THE GREAT BASIN AND A WEAK IMPULSE RIDING WESTERLY FLOW IN NORTHERN MEXICO SOUTH OF THE TEXAS BIG BEND. AT THE SURFACE...SOUTHEASTERLY FLOW CONTINUES TO ADVECT MOISTURE FROM THE GULF OF MEXICO WITH A COLD FRONT LOCATED ACROSS OKLAHOMA AND THE TEXAS PANHANDLE. A 1020MB HIGH IS LOCATED ACROSS THE ARKLAMISS. FOR THE REST OF THE AFTERNOON AND INTO THIS EVENING...WILL CONTINUE TO SEE CLOUDS BREAK UP AS MIXING AND DAYTIME HEATING CONTINUES. THICKER STRATOCU RESIDES OVER ZAPATA/JIM HOGG/STARR COUNTIES AND MAY BE A LITTLE HARDER TO BREAK UP CLOUDS IN THIS AREA. EVEN THOUGH THICK CLOUDS ARE LOCATED HERE...TEMPERATURES HAVE WARMED NICELY AND ARE ACTUALLY ABOVE FORECASTED HOURLY TEMPERATURES BUT LOOK GOOD FOR THE HIGHS THIS AFTERNOON. WEAK IMPULSE TO OUR WEST IS FORECAST TO SPARK CONVECTION ON THE SIERRA MADRE LATER THIS AFTERNOON AS IT MOVES EAST. LATEST HRRR AND SPC 4KM WRF CONTINUE TO ROLL CONVECTION OFF THE HIGHER TERRAIN AND MAKE A RUN AT OUR WESTERN ZONES. CURRENT 20 POPS OUT WEST LOOK GOOD FOR THIS EVENING AND MADE ONLY MINOR ADJUSTMENTS TO MOVE JUST A LITTLE EASTWARD. ANY STORMS THAT DO CREEP INTO OUR AREA WILL QUICKLY DISSIPATE TOWARDS MID EVENING AS BOUNDARY LEVEL STABILIZES. FOR TONIGHT...LOW CLOUDS WILL MOVE BACK IN ON SOUTHEASTERLY LOW LEVEL WINDS BY MID TO LATE EVENING. NAM12/RAP/HRRR SHOW SIGNALS OF SEA FOG DEVELOPING AND/OR ADVECTING IN TO THE COASTAL AREAS OVERNIGHT. ADDED AREAS OF FOG ALONG THE COASTLINE WITH PATCHY FOG INLAND. WILL HOLD OFF ON ANY DENSE FOG ADVISORY AT THIS TIME AND LET SWING SHIFT MAKE THE CALL. INCREASED LOW TEMPERATURES SLIGHTLY WITH EXPECTED ABUNDANCE OF LOW CLOUDS AND LOOKING AT MAINLY UPPER 60S TO LOWER 70S. FOR TUESDAY...WE WILL START OUT WITH THOSE LOW CLOUDS AND WILL BREAK OUT AND DISSIPATE BY LATE MORNING. MIXING WILL TAKE PLACE BY MID MORNING WITH GUSTY WINDS BY LATE MORNING. ANOTHER IMPULSE IS PROGGED TO MOVE ACROSS THE AREA EARLY TUESDAY AFTERNOON. THERE IS PLACEMENT ISSUES BETWEEN THE NAM AND GFS WITH THE NAM FURTHER NORTH AND THE GFS IS ACROSS THE NORTHERN PORTION OF THE AREA AND IS WEAKER THAN THE PREVIOUS RUN. KEPT POPS AS IS AND JUST TWEAKED LOCATION BASED ON 12Z GFS. A STRONG TO SEVERE STORM IS POSSIBLE GIVEN THE THERMODYNAMIC ENVIRONMENT. FOR TUESDAY NIGHT...THAT IMPULSE IS WELL NORTH OF THE AREA WITH JUST A FEW SHOWERS LEFT OVER IN THE COASTAL WATERS. ATMOSPHERE WILL STABILIZE RATHER RAPIDLY AFTER SUNSET WITH SKIES BECOMING CLOUDY ONCE AGAIN. COLD FRONT WILL SAG INTO NORTH CENTRAL TEXAS WITH A SFC LOW SOUTH OF THE TEXAS BIG BEND. CLOUDS WILL KEEP LOWS UP...COMPARABLE TO TONIGHT. .LONG TERM /WEDNESDAY THROUGH MONDAY/...12Z MODEL RUN REMAINS PERSISTENT ON THE TRACK AND STRENGTH OF THE MID TO UPPER LEVEL TROUGH CURRENTLY OVER THE GREAT BASIN. BY 18Z WEDNESDAY GFS PLACES THE UPPER TROUGH AXIS ACROSS NORTHWEST TEXAS AROUND 18Z WITH ITS ASSOCIATED COLD FRONT APPROACHING THE NORTHERN PORTIONS OF THE CWA. LARGE SCALE ASCENT COUPLED WITH LOW LEVEL CONVERGENCE ALONG THE FRONT SHOULD BE THE COMBINATION NEEDED TO BRING ABOUT THE CHANCE OF RAIN WE HAVE SEEN IN A WHILE. MODEST LOW LEVEL MOISTURE WILL BE IN PLACE AND A LATE AFTERNOON FRONTAL PASSAGE SHOULD ALLOW FOR SURFACE HEATING TO EXCEED GUIDANCE VALUES. SPC MAINTAINS GENERAL THUNDERSTORM CHANCES FOR WEDNESDAY BUT CAN NOT RULE OUT ISOLATED SEVERE STORMS AS THE ATMOSPHERE BECOMES INCREASINGLY UNSTABLE. A DAY TO DAY ANALYSIS TO TAKE PLACE BEFORE WE ADD SEVERE WORDING INTO THE FORECAST/GRIDS. POP GUIDANCE REMAINS AT LOW END CHANCE BUT THIS MIGHT BE ON THE LOW END WITH DYNAMICS LOOKING A BETTER THEN YESTERDAY AT THIS TIME. KEEP WED AND WEDNESDAY NIGHT POPS CLOSE TO THE PREVIOUS FORECAST. AS MENTIONED TEMPERATURES SHOULD CLIMB AHEAD OF THE COLD FRONT WITH A LATE AFTERNOON OR EARLY EVENING PASSAGE. FORECAST HIGHS TO REMAIN ABOVE GUIDANCE VALUES ESPECIALLY IF WE SEE MORE SUN PEAK THROUGH. TROUGH AXIS AND SURFACE LOW PRESSURE QUICKLY EXITS TO THE EAST THURSDAY MORNING. HUNG ON TO LOW POPS ACROSS THE COASTAL COUNTIES BEFORE ENDING THURSDAY AFTERNOON AS THIS SYSTEM OPENS AND PUSHES TO THE EAST. FAIR WEATHER ENSUES THURSDAY AFTERNOON INTO FRIDAY AS SHORTWAVE RIDGING BUILDS OVERHEAD. COOL TO MILD TEMPERATURES THURSDAY MORNING WITH SOME RECOVERY THURSDAY WITH HIGHS DROPPING TO SLIGHTLY EARLY APRIL NORMALS. GFS HAS BEEN INDICATING A QUICK RETURN OF GULF MOISTURE FRIDAY NIGHT INTO SATURDAY. A WEAK DISTURBANCE IN THE ZONAL FLOW HAS BEEN SEEN THE LAST FEW RUNS. ALTHOUGH GUIDANCE IS SHOWING VERY LOW POPS ON SATURDAY WILL UP THE CHANCES SLIGHTLY TO MENTION ISOLATED SHOWERS. MODEST DIVERGENCE AND SUFFICIENT MOISTURE...IF OCCURS MIGHT BE ENOUGH FOR A FEW SHOWERS. WIND MACHINE TO POSSIBLY TURN ON SUNDAY AND MONDAY AS NEXT TROUGH AND SURFACE LOW DEVELOP OUT WEST. TEMPERATURES TO CLIMB AS USUAL. && .MARINE /NOW THROUGH TUESDAY/GENERALLY FAVORABLE MARINE CONDITIONS ARE EXPECTED THROUGH TUESDAY NIGHT WITH MODERATE EASTERLY TO SOUTHEASTERLY WINDS. CONDITIONS MAY APPROACH EXERCISE CAUTION LEVELS ON THE GULF OF MEXICO TONIGHT. SEAS SHOULD REMAIN LOW TO MODERATE. WEDNESDAY THROUGH SUNDAY...COLD FRONT ON TAP FOR A LATE WEDNESDAY OR WEDNESDAY EVENING PASSAGE. LIGHT WINDS IN ADVANCE OF THE FRONT TO SHIFT AND INCREASE FROM THE NORTH. SMALL CRAFT ADVISORIES STILL EXPECTED WITH A 6 TO 12 HOUR WINDOW OF STRONG NORTH FLOW WEDNESDAY NIGHT INTO EARLY THURSDAY AS SURFACE LOW PRESSURE DEVELOPS EAST OF PADRE ISLAND ALONG THE FRONT. WITH THE SURFACE LOW TRACKING EAST FAIRLY QUICKLY THURSDAY NORTH TO NORTHEAST WINDS TO WEAKEN. WINDS VEER FRIDAY TO THE EAST AND SOUTHEAST BY FRIDAY NIGHT BUT THE RETURN FLOW REMAINS LIGHT TO MODERATE. MORE SUBSTANTIAL INCREASE OF SOUTHEAST WINDS RESUME SUNDAY INTO MONDAY AS THE GRADIENT TIGHTENS WITH LOW PRESSURE DEEPENING ACROSS WESTERN TEXAS AND NORTHEAST MEXICO. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 70 82 68 82 / 10 20 30 40 BROWNSVILLE 69 84 68 84 / 10 20 30 40 HARLINGEN 70 86 68 84 / 10 20 20 40 MCALLEN 70 87 70 86 / 10 30 20 40 RIO GRANDE CITY 70 90 70 87 / 20 30 20 30 SOUTH PADRE ISLAND 69 76 68 78 / 10 20 30 40 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 55...SHORT TERM 59...LONG TERM