Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/18/15


AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
515 PM PDT SUN MAY 17 2015 .SYNOPSIS...BELOW NORMAL TEMPERATURES WITH MOSTLY DRY CONDITIONS ARE EXPECTED TO CONTINUE THROUGH FRIDAY. THERE COULD BE A FEW SHOWERS OVER INTERIOR MOUNTAINS LATE TODAY AND AGAIN THURSDAY AS WEAK LOW PRESSURE DISTURBANCES MOVE ONSHORE. HIGH PRESSURE AND WARMER CONDITIONS ARE EXPECTED OVER THE MEMORIAL DAY WEEKEND. && .DISCUSSION...AS OF 02:16 PM PDT SUNDAY...DESPITE MID AND HIGH CLOUDS...MANAGING TO GET A FEW CONVECTIVE BUILDUPS OVER INTERIOR MOUNTAINS WHERE SUNSHINE IS MORE PREVALENT. HRRR MODEL CAPTURING THE CONVECTION OVER NORTHEAST SANTA CLARA COUNTY PRETTY WELL AND SHOULD PERSIST FOR A FEW MORE HOURS...THEN SHIFT EAST AND DECREASE THIS EVENING. MODEL ALSO SHOWS ACTIVITY FORMING OVER EASTERN SAN BENITO COUNTY AND PARTS OF MONTEREY COUNTY...BUT THICKER CLOUDS HAVE LIMITED CONVECTION. WOULD EXPECT SOME BUILDUPS AND POSSIBLY A SHOWER IN THIS AREA AS WELL LATER THIS AFTERNOON AS SOME BREAKS IN MID CLOUDS EXPECTED. OTHER AREA TO WATCH IS EXTREME NORTH BAY OVER ELEVATED TERRAIN...BUT NOT EXPECTING MORE THAN A FEW CUMULUS BUILDUPS. WELL MIXED MARINE LAYER PERSISTS AND IS AT LEAST 3000 FEET DEEP THIS AFTERNOON NEAR THE COAST AND BAY AREA. TEMPERATURES MOSTLY IN THE 60S AND NOT MUCH CHANGE EXPECTED IN THE CURRENT COOL TEMPERATURE REGIME THROUGH AT LEAST THURSDAY. MARINE LAYER SHOULD REMAIN DEEP THROUGH THE WEEK AS WELL WITH A LINGERING TROF ALONG THE COAST. SERIES OF SHORT WAVES WILL REINFORCE THIS TROF THROUGHOUT THE WEEK WITH ONE WAVE MOVING ACROSS THE AREA MONDAY AND ANOTHER ONE WEDNESDAY AND THURSDAY. STRONGEST FEATURE LOOKS TO ARRIVE THURSDAY AND PUSHES TOWARD SOUTHERN CALIFORNIA. MAIN IMPACT ON CENTRAL CALIFORNIA COAST WEATHER WILL BE PERSISTENT LOW CLOUDS ESPECIALLY NEAR THE COAST...COOL TEMPERATURES...AND MOSTLY DRY WEATHER. SHOWER THREAT SHOULD BE REDUCED MONDAY AND TUESDAY AS DYNAMICS AND MOISTURE SHIFT FURTHER INLAND. OUTSIDE CHANCE OF A SHOWER EACH AFTERNOON IN EXTREME NORTH BAY GIVEN INSTABILITY OVER TERRAIN. THURSDAY BRINGS A BETTER RISK FOR SHOWERS OVER INTERIOR AS THE STRONGEST WAVE IN THE SERIES BRINGS CYCLONIC CURVATURE AND SOME ADDED LIFT TO THE AREA. RIDGE BUILDS INTO COAST OVER THE WEEKEND...SO DRYING AND WARMING TREND EXPECTED FROM FRIDAY INTO SUNDAY. && .AVIATION...AS OF 5:15 PM PDT SUNDAY... TROUGH SITUATED JUST OFFSHORE OF THE CALIFORNIA COASTLINE THIS EVENING. SYSTEM WILL SWEEP INLAND AND CLOUD COVERAGE EARLY THIS EVENING. EXPECT PREDOMINATELY MVFR CONDITIONS WITH BASES 1800-2500 FT. BRIEF PERIODS OF VFR FEW/SCT CONDS POSBL FROM 00-03Z OVER MONTEREY BAY TERMINALS AND FURTHER INLAND AROUND THE SF BAY. ONSHORE FLOW WILL PREVAIL THROUGH THE NIGHT WITH SPEEDS UP TO 15 KT AND GUSTS AOA 20 KT. VICINITY OF KSFO... MVFR WITH ONSHORE FLOW THROUGH THE NEXT 24 HOURS. VFR POSBL IN EARLY AFTERNOON MON. KSFO BRIDGE APPROACH... SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS... VFR THROUGH THE NEXT FEW HOURS THEN MVFR WITH BASES 1500-2500FT THROUGH THE NIGHT. WEAK ONSHORE FLOW. VFR MIX OUT AOA 21Z MON. && .MARINE...AS OF 05:08 PM PDT SUNDAY...RELATIVELY LIGHT NORTHWESTERLY WINDS WILL PREVAIL OVER THE COASTAL WATERS THROUGH MIDWEEK. WINDS ARE FORECAST TO INCREASE LATE IN THE WEEK. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...NONE. $$ PUBLIC FORECAST: KBB AVIATION: DRP MARINE: DYKEMA VISIT US AT WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS EUREKA CA
335 PM PDT SAT MAY 16 2015 .SYNOPSIS...A SERIES OF UPPER LOWS WILL BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO MAINLY THE INTERIOR EACH AFTERNOON THROUGH MID WEEK. OTHERWISE DRY WEATHER CONDITIONS WITH BELOW NORMAL TEMPERATURES WILL CONTINUE TO PREVAIL THROUGH NEXT WEEK. && .DISCUSSION...AN UPPER LOW WILL APPROACH THE NORTH COAST TONIGHT INTO SUNDAY MORNING. PROFILES ARE NOT LOOKING ALL THAT IMPRESSIVE FOR STORMS THIS EVENING WITH LIFTED INDICES NEAR -1C...CAPE AROUND 300J/KG AND EQUILIBRIUM LEVELS NEAR 22KFT. WILL GO AHEAD AND TOSS ISOLATED SHOWERS AND STORMS INTO THE FORECAST OVER THE YOLLA BOLLYS AND TRINITY MOUNTAINS FOR EARLY THIS EVENING IN THE OUTSIDE CHANCE WE DO GET A FEW STRIKES. THIS WILL ALSO BLEND WITH NEIGHBORING CWA`S AND SPC`S GENERAL TSTM OUTLOOK. HIGH RESOLUTION MODELS SHOW THE ACTIVITY DYING DOWN THIS EVENING AFTER LOSS OF PEAK HEATING...THEN SPIKING UP AGAIN LATE TONIGHT INTO SUNDAY MORNING. CONFIDENCE IS NOT HIGH THIS WILL ACTUALLY OCCUR DUE TO THE RELATIVELY LOW CAPE AND WEAK FORCING FROM THE APPROACHING LOW PRESSURE SYSTEM ALOFT. THE POSSIBILITY DOES EXIST WE MAY SEE STORMS REDEVELOP IN THE EARLY MORNING HOURS...SO WILL GO AHEAD AND ADD THEM TO THE FORECAST. IF IT DOES NOT HAPPEN...OH WELL. SUNDAY IS STILL LOOKING BETTER FOR INTERIOR CONVECTION AS THE UPPER LOW APPROACHES CAPE MENDO. THE AREA OF GREATEST INSTABILITY AND PRECIP SHOULD SHIFT INTO WESTERN PORTIONS OF HUMBOLDT AND DEL NORTE COUNTIES WITH PERHAPS SOME ACTIVITY IN THE NE PORTION OF MENDOCINO COUNTY. CONFIDENCE THUNDERSTORMS WILL ADVECT OUT TO THE COAST IS NOT HIGH DUE TO WEAK SSE FLOW ALOFT TO PROPEL THE STORMS. ANY STORMS THAT DO MANAGE TO SPROUT UP WITH HEATING WILL PROBABLY QUICKLY COLLAPSE. THE GFS AND ECMWF HAVE BEEN TOO BROAD BRUSH WITH THE PRECIP SO WILL CONTINUE TO USE THE NAM12 AS THE PRIMARY GUIDANCE. THE HIRES-NMM AND HRRR HAVE BEEN MODELING THE CONVECTION FAIRLY GOOD AS WELL. THUS THE BROAD BRUSH GFS AND ECMWF FIELDS HAVE BEEN SCALED BACK. SHOWER AND ISOLATED STORM CHANCES WILL LIKELY PERSIST ON MONDAY AS THE UPPER LOW MEANDERS SOUTHWARD OVER CENTRAL CALIFORNIA. A BROAD LOW PRESSURE SYSTEM ALOFT WILL REMAIN OVER THE REGION ON TUE. CONVECTIVE PARAMETERS WERE NOT LOOKING AS FAVORABLE FOR STORMS ON TUE. IT IS STILL 3 DAYS OUT AND A LOT WILL CHANGE BETWEEN NOW AND THEN. SO WILL NOT MAKE TOO MANY CHANGES HERE. .LONG-TERM...WED THROUGH SAT...A BROAD AND COMPLEX LOW PRESSURE SYSTEM ALOFT WILL CONTINUE TO BRING A THREAT OF SHOWERS AND PERHAPS ISOLATED T-STORMS TO MAINLY THE INTERIOR THROUGH THU. MORE STABLE CONDITIONS MAY DEVELOP FRI INTO SAT AS A RIDGE ALOFT BUILDS CLOSER TO THE COAST. THE MODELS WERE NOT EXACTLY IN GREAT AGREEMENT HERE. THE GFS BUILDS A FLAT RIDGE OVER THE WEST COAST WHILE THE ECMWF HAS ANOTHER UPPER LOW DIVING SOUTHWARD. THE GEM WAS IN BETWEEN WITH BROAD CYCLONICALLY CURVED NORTH FLOW OVER THE AREA. CONSIDERING THE PERSISTENT LARGE SCALE TROUGH PATTERN AND THE DISCONGRUITY IN THE MODEL DATA...WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS IN THE INTERIOR FRI THROUGH SAT. && .AVIATION...VFR CEILING HAVE PERSISTED ALONG THE COASTAL AIR TERMINALS MOST OF THE DAY...ALTHOUGH CLOUDS MAY CONTINUE TO NUDGE SLIGHTLY WEST INTO ACV AND CEC THROUGH THE AFTERNOON. CEILINGS SHOULD BUILD BACK INTO COASTAL AREAS DURING THE LATE AFTERNOON /EVENING...THEN REMAIN MVFR THOUGH THE LATE MORNING HOURS ON SUNDAY. INLAND CONDITIONS SHOULD REMAIN VFR THROUGH THE NEXT TAF CYCLE. && .MARINE...GENERALLY LIGHT NORTHERLIES AND SMALL SHORT PERIOD SEAS ARE BEING OBSERVED ACROSS ALL WATERS. THESE CONDITIONS WILL REMAIN GENERALLY STEADY STATE THROUGH THE MIDDLE OF THE WEEK...AS WINDS ARE EXPECTED TO REMAIN IN THE MODERATE TO FRESH RANGE. A REINFORCING MID PERIOD WESTERLY SWELL WILL BUILD INTO THE WATERS OVER THE WEEKEND BUT IS NOT EXPECTED TO BE PARTICULARLY LARGE...WHILE A SMALL SOUTHERLY SWELL WILL CONTINUE TO MOVE THROUGH AS WELL. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...NONE. NORTHWEST CALIFORNIA COASTAL WATERS...NONE. && $$ VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA FOLLOW US ON FACEBOOK AND TWITTER AT: HTTP://WWW.FACEBOOK.COM/NWSEUREKA HTTP://WWW.TWITTER.COM/NWSEUREKA
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
540 PM MDT SUN MAY 17 2015 .SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT) ISSUED AT 331 PM MDT SUN MAY 17 2015 IN SPITE OF BUILDING HIGH PRESSURE OVER UTAH AND WARMING TEMPS ALOFT...AFTERNOON CAPE VALUES OF 250-500 J/KG SUGGEST CONVECTIVE SHOWERS WITH SOME THUNDERSTORMS. MOISTURE TRANSPORT DOES EXIST FROM THE UINTA MOUNTAINS TOWARD VAIL AND INDEPENDENCE PASS REGION...AND SHOWERS/STORMS WILL BE CONCENTRATED ACROSS THIS AREA. CONVECTIVE POTENTIAL EXIST ELSEWHERE BUT NOT AS NUMEROUS OVER SW COLORADO...AND MOSTLY DRY OVER SE UTAH. CONVECTIVE POTENTIAL MOSTLY DIMINISHES WITH SUNSET. NOT SO SURE THIS WILL BE THE CASE ACROSS PARTS OF ERN UTAH AS MOISTURE TRANSPORT INCREASES OVERNIGHT...THE HRRR SHOW CONVECTIVE SHOWERS PERSISTING PAST MIDNIGHT AND TRACKING OVER THE UINTA BASIN/MOUNTAINS. BY DAYBREAK...HIGH CLOUDS WILL BE SPREADING FROM THE SOUTH AS THE NEXT CALIFORNIA UPPER LOW ADVECTS MOISTURE TOWARDS THE FOUR CORNERS REGION. THE PACIFIC WAVE TRAIN CONTINUES MONDAY AS THE NEXT STORM SYSTEM MOVES SLOWLY ONSHORE...ITS CENTER SETTLING OVER CALIFORNIA/S SAN JOAQUIN VALLEY LATE IN THE AFTERNOON. SOUTHERLY FLOW AHEAD OF THE TROUGH WILL CAUSE MOISTURE LEVELS TO RISE ONCE AGAIN AS GULF MOISTURE IS TAPPED. GFS AND NAM BOTH INDICATED PRECIPITABLE WATER VALUES RISING TO NEAR 0.6 OF AN INCH. MEANWHILE...AN 110 KT JET ROTATES THROUGH THE BASE OF THE TROUGH GIVING IT A SLIGHTLY NEGATIVE TILT. THE NOSE OF THE JET PUSHES TOWARD THE FOUR CORNERS WHICH WILL PROVIDE CONSIDERABLE DIVERGENCE TO ADD TO THE DIFFLUENT FLOW ALOFT. THE DYNAMIC LIFT JUST DESCRIBED COMBINED WITH DAYTIME HEATING WILL GENERATE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FAVORING THE MOUNTAINS. AS MENTIONED IN THE PREVIOUS DISCUSSION...ARRIVING MOISTURE WILL BE HIGH BASED ACCORDING TO AREA TIME SECTIONS SO EXPECT MAIN STORM THREAT...ASIDE FROM LIGHTNING...WILL BE STRONG AND GUSTY OUTFLOW WINDS. WAA ADVECTION WILL CAUSE TEMPERATURES TO CLIMB CLOSER TO SEASONAL NORMS... THOUGH EXPECT CLOUDS AND SHOWERS WILL LIMIT HIGHS. THEREFORE... NUDGED MONDAY/S HIGHS TOWARD COOLER MAV GUIDANCE. MONDAY NIGHT WILL REMAIN ACTIVE AS THE PACIFIC SYSTEM MOVES OVER SOUTHERN NEVADA DURING THE NIGHT. DIFFLUENT/DIVERGENT FORCING REMAINS IN PLACE WHILE MOISTURE CONTINUES TO STREAM INTO THE AREA FROM THE SOUTH. AS A RESULT...WILL CONTINUE WITH LIKELY POPS IN THE MOUNTAINS WITH CHANCE POPS ACROSS THE VALLEYS. COLDER AIR BEGINS TO ADVECT OVER THE REGION DURING THE NIGHT CAUSING SNOW LEVELS TO LOWER TO AROUND 9000 TO 9500 FEET. EXPECT ACCUMULATING SNOW FOR AREAS ABOVE 10000 FEET WITH AMOUNTS OF UP TO 8 INCHES POSSIBLE ABOVE THE TIMBERLINE. MODELS SUGGEST AMOUNTS OF 12 INCHES OR MORE BUT APPEARS CONVECTIVE PARAMETERIZATION MAY BE A BIT OVERDONE AS LAPSE RATES ONLY MODERATELY UNSTABLE. IMPACTS TO ROADWAYS OVER THE HIGH PASSES PROBABLY NEGLIGIBLE WITH MOST SNOW MELTING ON CONTACT SO WILL HOLD OFF ISSUING HILITES. CLOUDS... SHOWERS AND WAA WILL YIELD MILDER OVERNIGHT LOWS AS PREVIOUSLY FORECAST. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 331 PM MDT SUN MAY 17 2015 COOL AND UNSETTLED CONDITIONS WILL CONTINUE TUESDAY AS THE PACIFIC STORM MOVES OVER THE REGION. SNOW LEVELS WILL RISE WITH DAYTIME WARMING...ESPECIALLY SOUTH...WHICH WILL INHIBIT ANY ADDITIONAL ACCUMULATIONS BELOW 10000 FEET. CONDITIONS IMPROVE TUESDAY NIGHT AS A TRANSIENT SHORTWAVE RIDGE BUILDS OVER THE AREA. ANOTHER LOW DEVELOPS OVER THE EASTERN PACIFIC AT MIDWEEK BUT STAYS QUASI-STATIONARY UNTIL THURSDAY NIGHT. A DRIER SOUTHWEST FLOW WILL MOVE OVER THE FORECAST AREA AHEAD OF THIS SYSTEM LIMITING MOIST CONVECTION TO THE MOUNTAIN AREAS DURING THE AFTERNOON AND EVENING WEDNESDAY AND THURSDAY. TEMPERATURES WILL RECOVER DURING THIS PERIOD REACHING NEAR NORMAL LEVELS THURSDAY AFTERNOON. THE PACIFIC SYSTEM THEN FOLLOWS THE WELL BEATEN PATH PREVIOUS STORMS HAVE TAKEN OVER THE PAST COUPLE OF WEEKS...TRACKING OVER EASTERN UTAH AND WESTERN COLORADO FRIDAY AND SATURDAY. CONSEQUENTLY...LOOK FOR AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY ONCE AGAIN ALONG WITH COOLER THAN NORMAL TEMPERATURES. CONDITIONS ON SUNDAY LESS CERTAIN AS LATEST ECMWF DRIVES A SHORTWAVE TROUGH ACROSS THE REGION FROM THE NORTHWEST WHILE GFS FAVORS A TRANSITORY RIDGE. BOTH SOLUTIONS POINT TO A CONTINUATION OF UNSETTLED CONDITIONS AS MOISTURE WILL LINGER IN EITHER CASE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 538 PM MDT SUN MAY 17 2015 SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL LINGER THROUGH 03Z BEFORE ENDING FOR THE NIGHT. EXPECT BRIEF MVFR CIGS IN THE VCNTY OF SHOWERS...WITH KASE AND KEGE MOST LIKELY TO BE IMPACTED THIS EVENING. VFR CONDS THEN EXPECTED THROUGH MIDDAY MONDAY...BEFORE ANOTHER SURGE OF MOISTURE MOVES IN. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS LATE MONDAY AFTERNOON AND EVENING...WITH CIGS DROPPING AND MOUNTAINS BECOMING OBSCURED. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...PF/NL LONG TERM...NL AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1147 PM MDT FRI MAY 15 2015 .UPDATE... ISSUED AT 543 PM MDT FRI MAY 15 2015 QUICK UPDATE TO BOOST POPS ACROSS MUCH OF THE FORECAST AREA FOR THE NEXT SEVERAL HOURS. LATEST HRRR AND 18Z RUNS A LITTLE MORE AGGRESSIVE OVERNIGHT AND WILL TREND POPS IN THIS DIRECTION. MINOR WIGGLES OR WAVES IN THE FLOW WILL CONTINUE TO SPARK AREAS OF SHOWERS WITH PERIODS OF NULL WEATHER ALSO EXPECTED THROUGH THE OVERNIGHT HOURS. && .SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT) ISSUED AT 352 PM MDT FRI MAY 15 2015 THE LOW PRESSURE SYSTEM OVER THE GREAT BASIN WILL VERY GRADUALLY SHIFT TO THE NORTHEAST TONIGHT AND CENTER ITS MAIN CORE OVER NORTHERN UTAH AT 500MB BY THE EARLY MORNING HOURS...WITH A WEAK CENTER OF CIRCULATION NEAR THE 4 CORNERS EMBEDDED IN THE GENERAL PATTERN AT THIS SAME TIME. THIS SYSTEM IS BROADLY ORGANIZED AND BECAUSE OF THAT...POCKETS OF NO SIGNIFICANT WEATHER AND POCKETS OF MODERATE TO HEAVY PRECIPITATION WILL OCCUR. CURRENT SATELLITE IMAGERY INDICATES AN AREA OF GOOD UPLIFT OVER THE PAGOSA SPRINGS/WOLF CREEK REGION. NE UTAH AND NW COLORADO ARE TRANSITIONING INTO A MORE STABLE AREA SO WILL SEE A BREAK FOR ABOUT 6 TO 12 HOURS THIS EVENING WITH THE OCCASIONAL ISOLATED SHOWER ABLE TO DEVELOP. COLD AIR IS ADVECTING INTO THE REGION WITH SNOW LEVEL EXPECTED TO DROP THROUGHOUT THE EVENING. GOOD VERTICAL VELOCITY FORECAST FOR THE FOUR CORNERS TONIGHT BETWEEN 5PM THIS EVENING THROUGH TOMORROW MORNING SO WILL EXPECT PRECIPITATION TO PICK UP THIS EVENING IN THIS AREA WITH EFFICIENT PRECIPITATION RATES...AND SNOW DOWN TO 7500 FEET AND FALLING BY MIDNIGHT. ANOMALOUSLY STRONG CLOSED LOW EJECTS NORTHEAST ACROSS THE WESTERN SLOPE ON SATURDAY. THE COLDEST AIR AND DYNAMICAL LIFT OCCURS WITH THIS FEATURE. THE BEST QPF WILL BE FOCUSED OVER THE SAN JUAN MOUNTAINS...ALTHOUGH THE WRN CO MOUNTAINS WILL GET A FAIR AMOUNT TONIGHT AND SATURDAY MORNING. A SECONDARY SHORT WAVE ROTATES INTO WRN COLORADO SATURDAY NIGHT. ALTHOUGH THIS SHORT WAVE ARRIVES FROM THE NORTHWEST...MODEL DATA SHOWS BRIEF MID LEVEL COLD ADVECTION SATURDAY EVENING (BUT NOT ANY COLDER THAN THE MAIN COLD CORE TONIGHT/SATURDAY). SNOW LEVELS WILL NOT FALL ANY LOWER THAN OCCURS SATURDAY MORNING...POSSIBLY BECOME SLIGHTER HIGHER GIVEN SLIGHTLY WARMER AIR AND LOWER QPF RATES. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 352 PM MDT FRI MAY 15 2015 SOME SHORT LIVED TERRAIN DRIVEN CONVECTIVE SHOWERS WILL OCCUR SUNDAY AFTERNOON...OTHERWISE A BRIEF RESPITE FROM THE RAIN OR SNOW. BUT THE NEXT PACIFIC CLOSED LOW BARRELS INTO CALIFORNIA ON MONDAY. A NEGATIVELY TILTED SHORT WAVE EJECTS ACROSS THE FORECAST AREA MONDAY NIGHT AND TUESDAY. LIKE THE CURRENT WEATHER SYSTEM...THIS GENERATES ANOTHER HEALTHY DOSE OF SHOWERS/STORMS WITH A FAIR AMOUNT OF RAINFALL. THIS WILL BE A WARMER SYSTEM AND SNOW WILL BE LIMITED TO ABOVE TIMBERLINE...MAYBE SNOW LEVELS LOWERING TO THE MOUNTAIN PASSES. DRIER SOUTHWEST FLOW PREVAILS OVER THE FOUR CORNERS REGION FOR THE WEDNESDAY THROUGH FRIDAY TIME FRAME. SOME DIURNAL CONVECTIVE SHOWERS MAY STILL FORM OVER THE MOUNTAIN AREAS...BUT THESE WILL NOT BE LONG LASTING AND PRODUCE LIGHT RAIN AMOUNTS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1126 PM MDT FRI MAY 15 2015 THIS VERY WET SYSTEM WILL CONTINUE TO IMPACT FLIGHT OPERATIONS ACROSS EASTERN UTAH AND WESTERN COLORADO OVER THE NEXT 24 HOURS. THREATS WILL BE LOWERED FLIGHT CRITERIA AND OCCASIONAL LIGHTNING DURING THE AFTERNOON AND EVENING TIME PERIODS FROM PASSING THUNDERSTORMS. MOST VALLEY LOCATIONS WILL BE ABLE TO SUSTAIN VFR CONDITIONS BUT TEMPORARY MVFR WILL BE POSSIBLE IN PASSING SHOWERS. AT THE MOUNTAIN TERMINALS SITES INCLUDING KASE...KTEX AND POSSIBLY KEGE...IFR CONDITIONS WILL ALSO BE POSSIBLE WITH REDUCTION TO BOTH VSBY AND CIGS COMING FROM SNOWFALL THROUGH 17/06Z. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ009-010- 012-018-019. WINTER STORM WARNING UNTIL 9 AM MDT SUNDAY FOR COZ009-010-012- 018-019. WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR COZ017. WINTER WEATHER ADVISORY UNTIL 9 AM MDT SUNDAY FOR COZ004-013. UT...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR UTZ028. && $$ UPDATE...JDC SHORT TERM...JAM/PF LONG TERM...PF AVIATION...JDC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
347 PM EDT SAT MAY 16 2015 .SYNOPSIS... A WARM FRONT WILL BE SLOW TO PUSH NORTH OF THE AREA THROUGH THIS EVENING...WHILE A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST...LINGERING NEARBY ON SUNDAY. A BACKDOOR COLD FRONT MOVES THROUGH SUNDAY NIGHT. THE FRONT STALLS JUST SOUTHWEST OF THE REGION ON MONDAY WITH HIGH PRESSURE BUILDING IN FROM THE NORTHEAST. THIS FRONT WILL LIFT THROUGH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD FRONT ON TUESDAY. HIGH PRESSURE IS THEN IN CONTROL INTO NEXT WEEKEND...WITH THE EXCEPTION OF A WEAK COLD FRONTAL PASSAGE ON FRIDAY && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... WARM FRONT LOCATED NEAR THE NYC METRO AS OF 19Z WILL CONTINUE TO SLOWLY LIFT NE THROUGH THE AREA THIS EVENING. IT IS POSSIBLE THE WARM FRONT DOES NOT COMPLETELY CLEAR FAR EASTERN ZONES UNTIL TONIGHT. DESTABILIZATION UNDERWAY WEST OF THE HUDSON RIVER WITH ENOUGH BREAKS IN THE CLOUDS FOR SUNSHINE TO WARM TEMPERATURES INTO THE UPPER 70S AND LOWER 80S...WITH DEW POINTS IN THE UPPER 50S AND LOWER 60S. LATEST HRRR AS WELL AS ITS PREVIOUS SEVERAL RUNS HAVE A BAND OF CONVECTION MOVING INTO THE LOWER HUDSON VALLEY AROUND 21-22Z. THIS HAS SUPPORT FROM THE 12Z NAM AND 15Z RAP AS WELL AS THE 12Z SPC WRF. SURFACE BASED INSTABILITY DIFFERS SOMEWHAT AMONG THE MODEL GUIDANCE...BUT HAVE ENOUGH CONFIDENCE THAT 800 TO 1200 J/KG OF SURFACE BASED CAPE WILL BE AVAILABLE ACROSS THE FAR NW INTERIOR FOR CONVECTION TO TAP INTO LATE THIS AFTERNOON AS IT MOVES INTO THE AREA. MODERATELY STRONG WESTERLY LOW-MID LEVEL FLOW SUPPORTS UNIDIRECTIONAL SHEAR AROUND 30 KT. A MARGINAL RISK OF SEVERE WEATHER PER SPC CONTINUES WEST OF THE HUDSON RIVER WHERE GREATEST SURFACE BASED INSTABILITY WILL RESIDE. THE THREAT IS FOR A STORM OR TWO TO CONTAIN DAMAGING WIND GUSTS. THE BAND OF CONVECTION WILL CONTINUE MOVING EAST THIS EVENING... REACHING THE NYC METRO AROUND 00Z. WITH MARITIME INFLUENCE ALONG AND EAST IF THE HUDSON RIVER...INSTABILITY WILL BE ELEVATED WITH LITTLE TO NO CHANCE FOR ANY SEVERE CONVECTION. CONVECTION SHOULD ELEVATED AND BEGIN TO WEAK AS IT MOVES OVER LONG ISLAND AND SOUTHERN CT. HOWEVER...MULTIPLE SHORT WAVES ALOFT ROUNDING THE TOP OF THE RIDGE MAY HELP TO SUSTAIN THE CONVECTION AS IT WORKS ITS WAY EAST. CURRENT FORECAST PACKAGE INDICATED LIKELY SHOWERS/STORMS WEST OF THE HUDSON AND LIKELY SHOWERS WITH A CHANCE OF THUNDERSTORMS EAST OF THE HUDSON. HIGH PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY DOWNPOURS IN ANY STORM. MINOR URBAN FLOODING IS A POSSIBILITY. CONVECTION DISSIPATES BY MIDNIGHT WITH SHOWERS LINGERING THROUGH DAYBREAK SUNDAY. TEMPERATURES TONIGHT WILL BE MILD IN THE 60S. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... DEEP UPPER LEVEL RIDGE BUILDS ACROSS THE EASTERN US ON SUNDAY. SURFACE TROUGH LINGERS ACROSS THE AREA. WITH A DRIER AIR MASS IN PLACE...EXPECTING MORE IN THE WAY OF SUNSHINE. THIS SHOULD ALLOW TEMPERATURES TO WARM INTO THE LOWER AND MIDDLE 80S INLAND AND IN THE NYC METRO...AND THE UPPER 70S CLOSER TO THE COAST. INSTABILITY WILL BE ON THE INCREASE DURING THE DAY FROM THE CITY NORTH AND WEST. AFTERNOON SEA BREEZES FURTHER EAST WILL LIMIT INSTABILITY. LOW CHANCE POPS FORECAST ACROSS WESTERN ZONES IN THE BETTER INSTABILITY AND WITH SURFACE TROUGH IN THE VICINITY. HOWEVER...THE UPPER LEVEL RIDGE SHOULD LIMIT CONVECTIVE DEVELOPMENT. IF A STORM DEVELOPS SUNDAY...IT MAY BE SLOW MOVING WITH WEAK LOW AND MIDDLE LEVEL FLOW. HIGH PRESSURE WILL BEGIN TO BUILD SW ACROSS THE AREA SUNDAY NIGHT SENDING A BACK DOOR FRONT THROUGH. MODELS DIFFER IN THE TIMING OF THE FRONT PASSAGE. CURRENT THINKING IS THAT THE FRONT WILL BEGIN MOVING SOUTH ACROSS THE AREA SUNDAY EVENING. WITH THIS FRONT...AN ISOLATED SHOWER OR STORM CANNOT BE RULED OUT. AS THE LOW LEVELS COOL AND MOISTEN BEHIND THE FRONT...SOME FOG OR DRIZZLE ARE POSSIBLE BY DAYBREAK MONDAY. LOW TEMPERATURES IN THE UPPER 50S AND LOWER 60S ARE FORECAST SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE OF NEXT WEEK. SLIGHT DIFFERENCES COME INTO PLAY WITH TIMING AND AMPLITUDE OF A SHORTWAVE TROUGH MOVING THROUGH NEW ENGLAND ON WED...ALTHOUGH SHOWER/TSTM ACTIVITY CURRENTLY LOOKS TO REMAIN TO OUR N. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE WEEK WITH ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING AROUND THE BASE RESULTS IN AMPLIFICATION. AT THE SFC...A FRONTAL BOUNDARY JUST TO THE SW OF THE AREA MON MORNING...WILL REMAIN NEARLY STATIONARY AS SUBSIDENCE FROM HIGH PRES TO THE NE NOSES IN. LOW LEVELS SATURATE EARLY IN THE MORNING AS A RESULT WITH STRATUS EXPECTED AND WITH WEAK LIFT IN THE SATURATED LAYER COULD CAUSE DRIZZLE. THERE IS ALSO A WEAK SHORTWAVE MOVING THROUGH THE FLOW ALOFT WHICH COULD CAUSE A FEW AREAS OF RAIN. THE LATTER WILL BE DETERMINED BY HOW MUCH DRY AIR IS IN PLACE ALOFT FROM THE HIGH. HAVE ADDED SLIGHT CHANCE RAIN OR DRIZZLE FOR A FEW HOURS MON MORNING AS A RESULT. WITH THE FRONT NEARBY THROUGH THE DAY...HAVE MAINTAINED THE SLIGHT CHANCE POPS MAINLY FROM NYC AND AREAS N AND W FOR ANY ACTIVITY THAT MAY DEVELOP IN THE AFTERNOON WITH WEAK AREAS OF VORTICITY MOVING THROUGH THE MID-LEVELS. MON NIGHT MAY END UP BEING DRY FOR THE MOST PART WITH MODEL TRENDS INDICATING THAT ANY ACTIVITY REMAINS TO OUR SW...BUT MAINTAINED THE SLIGHT CHANCE TO LOW CHANCE POPS FOR THE TIME BEING SINCE THERE IS UNCERTAINTY WITH HOW MUCH THE HIGH TO THE NE BUILDS IN. WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN THE EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH PRESSURE THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH THE END OF THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER ASSOCIATED WITH A WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI AFTERNOON/EVE. TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE PERIOD. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... A WARM FRONT LIFTS THROUGH THE REGION THIS AFTERNOON. A SURFACE TROUGH THEN CROSSES THE AREA TONIGHT. A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH SUNDAY MORNING...THEN BEGINS TO SINK SOUTH INTO THE TRI-STATE SUNDAY AFTERNOON. VFR OUTSIDE OF CONVECTION THROUGH THIS EVENING...EXCEPT FOR MVFR HAZE AT KHPN AND MVFR CEILINGS AT KGON. FOR TERMINALS W OF HUDSON HAVE GONE WITH PREVAILING SHRA/TEMPO TSRA LATE THIS AFTERNOON/EARLY THIS EVENING. FOR TERMINALS E OF THE HUDSON HAVE GONE WITH VCTS WITH TEMPO SHRA THIS EVENING. WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. FOR NOW HAVE CONTINUED WITH LOW END MVFR FORECAST (3SM/1000FT)...HOWEVER CANNOT RULE OUT IFR...OR EVEN VFR FOR THAT MATTER. WINDS MAINLY LIGHT AND VARIABLE OUTSIDE OF SEABREEZES THIS AFTERNOON...AND SOUND BREEZE KLGA AND SEABREEZE KJFK/KBDR/KGON LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON. .OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY... .SUNDAY AFTERNOON/EVENING...MAINLY VFR. MVFR OR LOWER POSSIBLE IN ANY ISOLD SHRA/TSTM. .SUNDAY NIGHT-MONDAY EVENING...MVFR OR LOWER POSSIBLE IN LOW CLOUDS/FOG. NE WINDS G15-20KT POSSIBLE DURING THE DAY ON MONDAY. .LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN FOG/STRATUS AND/OR SHRA/TSTM. .LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE. && .MARINE... S WINDS 10-20 KT ON THE OCEAN WATERS THIS AFTERNOON AND EVENING DIMINISH TONIGHT. BRIEF GUSTY WINDS ARE ALSO POSSIBLE IN ANY SHOWER AND THUNDERSTORMS THAT MAY MOVE ACROSS THE WATERS. OTHERWISE...SUB-SCA CONDITIONS ARE FORECAST FOR THE REMAINDER OF THE FORECAST PERIOD WITH A RELATIVELY LIGHT FLOW PERSISTING ACROSS THE AREA. GUSTS MAY REACH AROUND 20 KT LATE TUE NIGHT THROUGH WED. && .HYDROLOGY... BASIN AVERAGE RAINFALL OF 1/4 INCH IS POSSIBLE THROUGH SUNDAY MORNING WITH LOCALIZED HIGHER AMOUNTS IN A BAND OF SHOWERS AND THUNDERSTORMS. MINOR URBAN FLOODING IS POSSIBLE IN ANY OF THE HEAVIER SHOWERS/STORMS. AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL SYSTEM ON TUE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...DS/24 NEAR TERM...DS SHORT TERM...DS LONG TERM...24 AVIATION...MALOIT MARINE...DS/24 HYDROLOGY...DS/24
AREA FORECAST DISCUSSION
NWS NEW YORK NY
139 PM EDT SAT MAY 16 2015 .SYNOPSIS... A WARM FRONT WILL BE SLOW TO PUSH NORTH OF THE AREA THIS AFTERNOON... WHILE A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST THIS EVENING AND STALLS OUT ACROSS THE AREA ON SUNDAY. A BACKDOOR COLD FRONT MOVES THROUGH LATE SUNDAY NIGHT AS HIGH PRESSURE BUILDS SOUTH ALONG THE NEW ENGLAND COAST. THE FRONT WILL THEN RETURN NORTH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD FRONT LATE TUESDAY. HIGH PRESSURE WILL THEN BUILD IN FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WARM FRONT LOCATED NEAR THE NYC METRO AS OF 17Z WILL CONTINUE TO SLOWLY LIFT NE OF THE AREA THROUGH THIS AFTERNOON. ENOUGH BREAKS IN THE CLOUDS SHOWING UP ON VISIBLE SATELLITE IMAGERY FOR HIGHER CONFIDENCE IN ACHIEVING HIGH TEMPERATURE FORECAST OF HIGHS IN THE LOWER 80S INLAND AND INVOF NYC METRO...AND MAINLY IN THE 70S ELSEWHERE. INSTABILITY WILL BEGIN TO INCREASE THIS AFTERNOON WEST OF THE HUDSON RIVER AHEAD OF MID LEVEL IMPULSE AND WEAK SHORTWAVE. A LEE TROUGH ALSO DEVELOPS ACROSS E PA AND APPROACHES LATE THIS AFTERNOON. LATEST 15Z HRRR GUIDANCE AS WELL AS ITS PREVIOUS SEVERAL RUNS HAVE A BAND OF CONVECTION MOVING INTO THE LOWER HUDSON VALLEY AROUND 21-22Z. THIS HAS SUPPORT FROM THE 12Z NAM AND 15Z RAP AS WELL AS THE 00Z SPC WRF. SURFACE BASED INSTABILITY DIFFERS SOMEWHAT AMONG THE MODEL GUIDANCE...BUT HAVE ENOUGH CONFIDENCE THAT 800 TO 1200 J/KG OF SURFACE BASED CAPE WILL BE AVAILABLE ACROSS THE FAR NW INTERIOR FOR CONVECTION TO TAP INTO LATE THIS AFTERNOON AS IT MOVES INTO THE AREA. MODERATELY STRONG WESTERLY LOW-MID LEVEL FLOW SUPPORTS UNIDIRECTIONAL SHEAR AROUND 30 KT. THE STREAK OF 23 CONSECUTIVE DAYS...APRIL 23 TO MAY 15...OF NO MEASURABLE PRECIPITATION AT CENTRAL PARK HAS ENDED TODAY WITH 0.09 INCHES OF RAIN OCCURRING THIS MORNING. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... A BAND OF CONVECTION WILL BE MOVING INTO LOCATIONS WEST OF THE HUDSON RIVER THIS EVENING...REACHING THE NYC METRO AROUND 00Z. A MARGINAL RISK OF SEVERE WEATHER PER SPC CONTINUES WEST OF THE HUDSON RIVER WHERE GREATEST SURFACE BASED INSTABILITY WILL RESIDE. THE THREAT IS FOR A STORM OR TWO TO CONTAIN DAMAGING WIND GUSTS. WITH MARITIME INFLUENCE FURTHER EAST...INSTABILITY WILL BE ELEVATED WITH LOWER CHANCE FOR ANY SEVERE CONVECTION. CONVECTION LIKELY BECOMES ELEVATED AND WEAKER AS IT MOVES EAST OF THE HUDSON. HOWEVER...MULTIPLE SHORT WAVES ALOFT ROUNDING THE TOP OF THE RIDGE MAY HELP TO SUSTAIN THE COMPLEX AS IT WORKS TOWARD THE COAST. HIGH PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY DOWNPOURS. MINOR URBAN FLOODING IS A POSSIBILITY. CONVECTION IS FORECAST TO DISSIPATE BY DAYBREAK SUN WITH A QUIETER DAY EXPECTED WITH THE UPPER RIDGE BUILDING DIRECTLY OVERHEAD. SHOULD SEE SOME PARTIAL CLEARING WITH HIGHS ABOVE NORMAL BY ABOUT TEN DEGREES. UPPER RIDGE AXIS BUILDS INTO THE CANADIAN MARITIMES SUN NIGHT...STRENGTHENING THE LOW-LEVEL RIDGE ACROSS THE NE AND ALLOWING FOR A BACKDOOR COLD FRONTAL PASSAGE. THIS SHOULD RESULT IN MUCH COOLER CONDITIONS WORKING IN ON MON. && .LONG TERM /MONDAY THROUGH FRIDAY/... THE WESTWARD EXTENT OF THE BACKDOOR COLD FRONT WILL BE A KEY PLAYER IN DETERMINING IF THE AREA STAYS OUT OF CONVECTION ON MON AND HOW COOL TEMPS GET. 00Z CYCLE SHOWS THE FRONT GETTING TO THE LEE OF THE POCONOS AND CATSKILLS. THIS MAY RESULT IS SOME SHOWER ACTIVITY OVER THE WESTERN PORTIONS OF THE AREA. THE FRONT APPROACHES AS WARM FRONT TUE MORNING. THE FLOW ALOFT TURNS MORE CYCLONIC...AND INCREASING MOISTURE AND LIFT COULD PRODUCE SOME SHOWERS...PRIMARILY OVER THE WESTERN HALF OF THE CWA. A TRAILING COLD FRONT APPROACHES TUE AFT AND IS PROGGED TO BE THROUGH BY EARLY EVENING. THERE IS A GOOD CHANCE OF CONVECTION ALONG AND AHEAD OF THE FRONT TUE. HIGH PRESSURE BUILDS IN FOR WEDNESDAY THROUGH FRIDAY. A MODERATE DOWNSLOPE FLOW SHOULD BE ABLE TO OFFSET SOME OF THE COLD AIR ADVECTION...KEEPING HIGHS NEAR NORMAL ON WEDNESDAY. TEMPS ALOFT THEN WARM UP ON THURSDAY AND FRIDAY...WITH HIGHS A LITTLE WARMER THAN THOSE ON WEDNESDAY. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... A WARM FRONT LIFTS THROUGH THE REGION THIS AFTERNOON. A SURFACE TROUGH THEN CROSSES THE AREA TONIGHT. A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH SUNDAY MORNING...THEN BEGINS TO SINK SOUTH INTO THE TRI-STATE SUNDAY AFTERNOON. VFR OUTSIDE OF CONVECTION THROUGH THIS EVENING...EXCEPT FOR IFR NEXT COUPLE OF HOURS AT KGON. FOR TERMINALS W OF HUDSON HAVE GONE WITH PREVAILING SHRA/TEMPO TSRA LATE THIS AFTERNOON/EARLY THIS EVENING. FOR TERMINALS E OF THE HUDSON HAVE GONE WITH VCTS WITH TEMPO SHRA THIS EVENING. WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. FOR NOW HAVE CONTINUED WITH LOW END MVFR FORECAST (3SM/1000FT)...HOWEVER CANNOT RULE OUT IFR...OR EVEN VFR FOR THAT MATTER. WINDS MAINLY LIGHT AND VARIABLE OUTSIDE OF SEABREEZES THIS AFTERNOON...AND SOUND BREEZE KLGA AND SEABREEZE KJFK/KBDR/KGON LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON. .OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY... .SUNDAY AFTERNOON/EVENING...MAINLY VFR. MVFR OR LOWER POSSIBLE IN ANY ISOLD SHRA/TSTM. .SUNDAY NIGHT-MONDAY EVENING...MVFR OR LOWER POSSIBLE IN LOW CLOUDS/FOG. NE WINDS G15-20KT POSSIBLE DURING THE DAY ON MONDAY. .LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN FOG/STRATUS AND/OR SHRA/TSTM. .LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE. && .MARINE... S WINDS 5-10 KT BECOME 10-20 KT ON THE OCEAN WATERS THIS AFTERNOON...THEN WILL DIMINISH TONIGHT. WITH A LIGHT PRES GRADIENT OVER THE AREA THROUGH THE START OF THE NEW WEEK...SUB-SCA CONDITIONS ON TAP WITH SEAS 2-4 FT ON THE OCEAN WATERS AND 1 FT OR LESS ON THE SOUND/HARBOR/BAYS. && .HYDROLOGY... BASIN AVG RAINFALL OF 1/4 TO 1/2 INCH IS POSSIBLE THROUGH TONIGHT WITH LOCALIZED HIGHER AMOUNTS AS A COMPLEX OF SHOWERS AND THUNDERSTORMS MOVES IN FROM PA TONIGHT. A QUARTER TO HALF INCH OF RAINFALL IS POSSIBLE LATE MONDAY NIGHT THROUGH TUESDAY WITH A COLD FRONTAL PASSAGE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...DW NEAR TERM...DS/DW SHORT TERM...DS/DW LONG TERM...DW/JC AVIATION...MALOIT MARINE...MPS HYDROLOGY...DW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
716 AM EDT SAT MAY 16 2015 .SYNOPSIS... SCATTERED SHOWERS THIS MORNING AS A WARM FRONT MOVES ACROSS THE REGION. WARM AND MORE HUMID WEATHER FOLLOWS SUNDAY. THEN A BACKDOOR COLD FRONT USHERS IN MUCH COOLER AIR INTO THE REGION SUNDAY NIGHT THROUGH EARLY NEXT WEEK. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS TO THE REGION MON NIGHT INTO TUE FOLLOWED BY DRY WEATHER MID TO LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 715 AM UPDATE... BATCH OF SHOWERS MOVING EWD THROUGH CT THIS MORNING WILL BE FOCUSED MAINLY ALONG THE CT S COAST TO COASTAL RI...WITH ISOLD SHOWERS POSSIBLE REMAINDER OF SNE THIS MORNING. SOME ELEVATED INSTABILITY EXISTS AND NOTED SOME LIGHTNING EARLIER ACROSS SE NY SO CANT RULE OUT AN ISOLD TSTM ACROSS S COASTAL RI. HRRR SUGGESTS SHOWERS EXITING THE REGION BY MIDDAY. UPDATED POPS TO REFLECT CURRENT RADAR TRENDS. PREVIOUS DISCUSSION... AFTER THIS MORNING...EXPECT LITTLE IN THE WAY OF PRECIP FOR THE REMAINDER OF THE DAY. THE EXCEPTION TO THIS COULD BE LATE IN THE DAY CONVECTION FROM WESTERN NEW YORK STATE/PENNSYLVANIA COULD MOVE EASTWARD INTO THE SOUTHWESTERN PORTIONS OF SOUTHERN NEW ENGLAND. WITH MOSTLY CLOUDY SKIES MUCH OF THE DAY AND DIMINISHING DAYTIME INSTABILITY...EXPECT A FEW SHOWERS TO BE THE EXTENT OF THE PRECIP REACHING THIS AREA. TEMPERATURE FORECAST IS A BIT COMPLICATED. WHILE NOT EXPECTING WIDESPREAD PRECIP TODAY...DO EXPECT SKY TO REMAIN MOSTLY CLOUDY TO OVERCAST. THIS COULD LIMIT TEMPERATURES SOMEWHAT...THOUGH ANY PEEKS OF SUN WILL ALLOW TEMPS TO JUMP UP. FOR NOW...WENT AGAIN WITH THE HIRES GUIDANCE WHICH GAVE HIGH TEMPS AROUND 70 FOR MUCH OF THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT...UPPER RIDGE CONTINUES TO BUILD INTO THE NORTHEAST U.S. WHILE THE WARM FRONT CONTINUES TO MOVE NORTH OF SOUTHERN NEW ENGLAND. ASIDE FROM THE FEW SHOWERS MENTIONED ABOVE...EXPECT MUCH OF THE NIGHT TO BE DRY. OVERCAST SKIES CONTINUE...INSULATING US FROM ABOVE. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE UPPER 50S TO AROUND 60. SUNDAY...THE BACK DOOR COLD FRONT HAS SLOWED SUBSTANTIALLY SINCE LAST NIGHTS MODEL RUNS. THIS WILL LEAD TO A MUCH WARMER DAY THAN PREVIOUSLY FORECAST. UPPER RIDGE HOLDS STRONG ACROSS THE NORTHEAST AND SEABREEZES ARE LIKELY TO DEVELOP WITH LIGHT FLOW ALOFT. THIS WILL KEEP TEMPERATURES ALONG THE IMMEDIATE COAST IN THE MID TO UPPER 60S. HOWEVER...FARTHER INLAND...HIGHS SHOULD CLIMB INTO THE LOW 80S FOR MOST LOCATIONS. EXPECT MOSTLY SUNNY SKIES AS WELL WITH DIURNAL CU FORMING DURING THE AFTERNOON HOURS. SHOULD BE THE PICK OF THE WEEKEND. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * MAINLY DRY AND COOLER SUN NIGHT AND MONDAY * A PERIOD OF SHOWERS LIKELY MON NIGHT AND TUE FOLLOWED BY DRY AND SEASONABLE WEATHER MID TO LATE NEXT WEEK OVERVIEW... MODELS ARE IN GOOD AGREEMENT ON THE LARGE SCALE FLOW DURING THE EXTENDED PERIOD. MID LEVEL SHORTWAVE MOVING S FROM NOVA SCOTIA WILL BRING A BACKDOOR FRONT ACROSS SNE SUN NIGHT WHICH WILL USHER IN A MUCH COOLER MARITIME AIRMASS LATE SUN NIGHT INTO MON. THEN NEXT MID LEVEL TROF MOVES EAST FROM THE UPPER MIDWEST WHICH WILL LIKELY BRING A PERIOD OF SHOWERS MON NIGHT AND ESPECIALLY TUE. THIS TROF WILL SETTLE ACROSS SE CANADA MID TO LATE WEEK BRINGING MAINLY DRY AND SEASONABLE WEATHER. SUN NIGHT AND MON... BACKDOOR FRONT MOVES ACROSS SNE SUN NIGHT AS STRONG RIDGE NOSES DOWN FROM THE MARITIMES TO THE GULF OF MAINE. LOW LEVEL NE FLOW WILL LEAD TO INCREASING LOW LEVEL MOISTURE AND AN EXPANSION OF STRATUS AND PATCHY FOG LATE SUN NIGHT INTO EARLY MON ALONG WITH THE POSSIBILITY OF SOME PATCHY DRIZZLE. CLOUDS SHOULD LIFT AND GIVE WAY TO PTSUNNY SKIES BY MON AFTERNOON...BUT CLOUDS COULD LINGER ALONG THE COAST. WITH DEVELOPING SUNSHINE HIGHS ON MON SHOULD RECOVER INTO THE MID/UPPER 60S AND SOME LOWER 70S CT VALLEY...BUT CLOSER TO 60 ALONG E COASTAL MA. MON NIGHT INTO TUE... DEEPENING MOISTURE PLUME AHEAD OF APPROACHING COLD FRONT MOVES INTO SNE LATE MON NIGHT AND TUE. MODEST LOW LEVEL JET ACTING ON 1.5"+ PWATS ALONG WITH MARGINAL ELEVATED INSTABILITY WILL RESULT IN A PERIOD OF SHOWERS AND PERHAPS AN ISOLD TSTM LATE MON NIGHT INTO TUE. TIMING NOT CERTAIN AT THIS TIME RANGE BUT IT APPEARS BEST CHANCE OF SHOWERS WILL BE DURING TUE...ESPECIALLY AFTERNOON ACROSS E NEW ENG. HIGHS TUE IN THE 60S. A FEW SHOWERS COULD LINGER INTO TUE EVENING ALONG THE COAST...OTHERWISE DRYING MOVES IN TUE NIGHT BEHIND THE FRONT. WED THROUGH FRI... LONG WAVE TROF SETS UP ACROSS SE CANADA WITH HIGH PRES IN CONTROL LEADING TO MAINLY DRY AND SEASONABLE CONDITIONS. && .AVIATION /11Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY/... TODAY...HIGH CONFIDENCE. MAINLY VFR. A FEW SHOWERS THIS MORNING WITH BRIEF MVFR VSBY POSSIBLE ESPECIALLY CT AND S RI. TONIGHT...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR CONDITIONS IN LOW CLOUDS AND PATCHY FOG. SUNDAY...HIGH CONFIDENCE. VFR. SEABREEZES DEVELOP ALONG THE EAST AND SOUTH COASTS ABOUT 14-15Z. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... SUN NIGHT AND MON...MODERATE CONFIDENCE. WINDS BECOMING NE FROM E TO W SUN NIGHT BEHIND A BACKDOOR FRONT WITH IFR STRATUS AND PATCHY FOG DEVELOPING LATE SUN NIGHT INTO MON MORNING...THEN IMPROVING TO VFR MON AFTERNOON BUT MVFR CIGS MAY LINGER ALONG THE COAST. MON NIGHT AND TUE...MODERATE CONFIDENCE. AREAS OF MVFR/IFR REDEVELOPING WITH SCT TO NUMEROUS SHOWERS AND POSSIBLY A TSTM...ESPECIALLY TUE. WED...MODERATE CONFIDENCE. VFR. DRY WEATHER LIKELY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY/...HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE OVER THE WATERS. SOUTHERLY WINDS 10 TO 15 KTS THROUGH THE PERIOD WITH GUSTS TO 20 KTS TODAY...SHIFTING TO LIGHT AND VARIABLE SUNDAY. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... SUN NIGHT AND MON...HIGH CONFIDENCE. A PERIOD OF NE GUSTS TO 20 KT LIKELY LATE SUN NIGHT INTO EARLY MON...WITH E WINDS MON AFTERNOON TURNING SOUTHERLY MON NIGHT. VSBYS MAY BE REDUCED IN PATCHY FOG. TUE...HIGH CONFIDENCE. PREFRONTAL S/SW WINDS INCREASING TO 20 KT INTO TUE EVENING WITH LOW PROB FOR A FEW G25 KT...THEN SHIFTING TO NW LATE MON NIGHT BEHIND FROPA. SHOWERS AND PATCHY FOG WILL REDUCE VSBYS. WED...HIGH CONFIDENCE. W/NW WINDS WITH GUSTS TO 20-25 KT. MARGINAL SCA CONDITIONS POSSIBLE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/RLG NEAR TERM...KJC/RLG SHORT TERM...RLG LONG TERM...KJC AVIATION...KJC/RLG MARINE...KJC/RLG
AREA FORECAST DISCUSSION
NWS ALBANY NY
159 AM EDT SAT MAY 16 2015 .SYNOPSIS... A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION OVERNIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM WEATHER SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... CLOUD COVER CONTINUES TO LOWER WITH SHOWERS DEVELOPING AND MOVING INTO THE FORECAST AREA AHEAD OF THE APPROACHING WARM FRONT/LOW PRESSURE SYSTEM AND UPPER LEVEL SHORT WAVE TROUGH. SHOWERS HAVE BEEN VERY LIGHT THUS FAR AS THE ATMOSPHERE IS RATHER DAY AS NOTED BY THE VERY DRY LAYER FROM 1000-700 MB ON THE 00Z/ALY SOUNDING. HRRR SHOWS SHOWERS MOVING ACROSS THE AREA THROUGH THE EARLY MORNING HOURS. USED REGIONAL RADARS AND HRRR TO ADJUST POPS. THERE HAS BEEN A FEW LIGHTNING STRIKES ACROSS CENTRAL NEW YORK WHICH LINES UP FAIRLY WELL WITH THE MODELED SHOWALTER INDICES. THE -2 TO ZERO INDICES MOVES ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA...USED THIS AS A GUIDE WHERE TO MENTION SLIGHT CHANCE OF THUNDER FOR THE OVERNIGHT/EARLY MORNING HOURS. OVERALL DID ADJUST TEMPERATURES UP A BIT...HAVE LOWS MAINLY IN THE 50S WITH SOME 40S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS INTO THE NORTHERN BERKSHIRES. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/... THE WARM FRONT WILL CROSS THE REGION SATURDAY MORNING AND THAT SHOULD BRING TO AN END ANY STEADY RAINFALL THAT MAY OCCUR AHEAD OF IT. A WEAK COLD FRONT AND SOME DRIER AIR WILL TRY TO PUSH SOUTHWARD INTO THE REGION SATURDAY AFTN AND NIGHT. IT WILL NOT BE SOUTH OF THE REGION UNTIL EARLY SUNDAY MORNING. AS A RESULT... THERE WILL STILL BE A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS SATURDAY AFTN AND NIGHT...ESPECIALLY AREAS SOUTH OF ALBANY. HAVE GENERALLY FORECAST 20 TO 30 PERCENT POPS FROM THE CAPITAL DISTRICT NORTH DURING SATURDAY AFTERNOON...AND 30 TO 40 PERCENT POPS TO THE SOUTH. THESE POPS CONTINUE TO DECREASE SATURDAY NIGHT WITH MOST OF THE REGION DRY BY SUNRISE SUNDAY. THE DRIER AIR BEHIND THIS WEAK COLD FRONT WILL RESULT IN FAIR AND WARM WEATHER SUNDAY AND SUNDAY NIGHT. HIGHS SATURDAY WILL BE IN THE UPPER 60S AND 70S. LOWS SATURDAY NIGHT GENERALLY 50 TO 60. HIGHS SUNDAY 75 TO 85. LOWS SUNDAY NIGHT IN THE UPPER 40S AND 50S. && .LONG TERM /MONDAY THROUGH FRIDAY/... THE LONG TERM PERIOD WILL BEGIN SOMEWHAT UNSETTLED...BEFORE FAIR WEATHER AND COOLER TEMPERATURES DOMINATE FOR THE BULK OF THE REMAINDER OF THE LONG TERM. FOR MON...A SHARP UPPER LEVEL RIDGE WILL CREST OVER THE REGION BEFORE MOVING OFF THE NEW ENGLAND COAST LATE IN THE DAY. AT THE SFC...A BACKDOOR COLD FRONTAL BOUNDARY SHOULD START OUT ACROSS CENTRAL NYS...POSSIBLY EXTREME WESTERN AREAS OF THE REGION IN THE MORNING. THIS BOUNDARY SHOULD WEAKEN...BEFORE DRIFTING BACK EAST LATER IN THE DAY. ALSO...A MUCH STRONGER COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES REGION. IT APPEARS THAT SHOWERS SHOULD SLOWLY EXPAND EASTWARD ACROSS THE REGION DURING THE DAY. HOWEVER...GIVEN THE SHARPNESS OF THE UPPER LEVEL RIDGE...IT IS QUITE POSSIBLE THAT AREAS EAST OF THE HUDSON RIVER REMAIN DRY THROUGH SUNSET. SO...WILL ONLY GRADUALLY INCREASE POPS INTO THE CHC RANGE FOR WESTERN AREAS...AND MAINLY SLIGHT CHC FOR EASTERN AREAS BY LATE IN THE DAY...WITH MAINLY DRY CONDITIONS FOR ALL AREAS IN THE MORNING. TEMPERATURES WILL BE WARMEST ACROSS THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK RIVER VALLEY...WHERE TEMPS NEAR 80 ARE EXPECTED. ELSEWHERE...A MARINE MODIFIED AIR MASS SHOULD RESULT IN SLIGHTLY COOLER TEMPS FURTHER SOUTH AND EAST...WITH GENERALLY 70S FOR VALLEYS...AND UPPER 60S/LOWER 70S ACROSS HIGHER ELEVATIONS. MON NT-TUE...THE COLD FRONT ACROSS THE GREAT LAKES REGION SHOULD SLOWLY SWING EAST ACROSS THE REGION. THIS SHOULD RESULT IN SOME ROUNDS OF SHOWERS AND POSSIBLE THUNDERSTORMS. THE BEST CHANCE FOR SIGNIFICANT RAINFALL WILL BE ACROSS THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY...WHICH WILL BE CLOSER TO THE PASSING UPPER LEVEL DYNAMICS. SHOWERS MAY TEND TO BECOME MORE SCATTERED FOR AREAS SOUTH AND EAST OF ALBANY. DEPENDING ON THE SPEED OF THE FRONT...SHOWERS MAY TEND TO TAPER OFF FROM NW TO SE TUE AFTERNOON. ALTHOUGH MID/UPPER LEVEL WINDS WILL STRENGTHEN...AT THIS TIME...MID LEVEL LAPSE RATES DO NOT APPEAR VERY STRONG...SO AT LEAST AT THIS TIME RANGE...IT APPEARS THAT THE OVERALL THREAT FOR WIDESPREAD STRONG/SEVERE THUNDERSTORMS SHOULD BE LOW. MON NT/TUE AM MIN TEMPS SHOULD BE MILD...MAINLY IN THE 50S TO LOWER 60S. TUE MAX TEMPS ARE TRICKY...DEPENDING ON HOW MUCH SUN CAN BREAK OUT. ASSUMING CLOUDS REMAIN FAIRLY WIDESPREAD...CURRENT FORECAST MAX TEMPS ARE IN THE 70- 75 RANGE IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. HOWEVER...IF THE FRONT SLOWS DOWN AND SOME BREAKS CAN DEVELOP...MUCH WARMER MAXES COULD OCCUR. TUE NT-FRI...LARGE HIGH PRESSURE SHOULD SLOWLY BUILD ACROSS THE REGION FROM THE GREAT LAKES. MOST LONG TERM GUIDANCE SUGGESTS ANOMALOUSLY COOL MID/UPPER LEVEL HEIGHTS AND CORRESPONDING H925-850 TEMPS. THERE COULD BE SPOTTY SHOWERS/SPRINKLES IN ASSOCIATION WITH THE UPPER LEVEL COLD POOL AND EVEN SOME WEAK LAKE EFFECT PROCESSES FOR TUE NT-WED ACROSS THE SOUTHWEST ADIRONDACKS. OTHERWISE...TEMPS WILL BE QUITE COOL WED...WITH MAXES ONLY REACHING 60-65 IN VALLEYS...AND 50S FOR MOST HIGHER ELEVATIONS...ALTHOUGH SOME OF THE HIGHEST PEAKS OF THE SOUTHERN ADIRONDACKS AND SOUTHERN VT MAY ONLY REMAIN IN THE 40S. OVERNIGHT MIN TEMPS FOR TUE NT/WED AM WILL MAINLY BE IN THE 40S TO LOWER 50S. FOR WED NT/THU AM...MIN TEMPS SHOULD BE EVEN COOLER...WITH 30S ACROSS THE WESTERN ADIRONDACKS...AND 40S ELSEWHERE. THERE COULD BE SOME FROST ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS...WHERE THE GROWING SEASON BEGINS MAY 21. THU AND FRI MAX TEMPS SHOULD WARM SLIGHTLY...WITH LOWER 70S IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. MIN TEMPS FOR THU NT/FRI AM SHOULD FALL INTO THE 40S FOR MOST AREAS. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... A WARM FRONT WILL MOVE ACROSS ERN NY AND WRN NEW ENGLAND LATE THIS MORNING INTO THE EARLY AFTERNOON. THE REGION WILL BE IN A WARM SECTOR BRIEFLY LATE THIS AFTERNOON INTO THE EARLY EVENING. A COLD FRONT WILL MOVE THROUGH TONIGHT...BEFORE HIGH PRESSURE RIDGES IN FOR SUNDAY. VFR CONDITIONS THIS MORNING WILL LOWER TO HIGH MVFR LEVELS IN TERMS OF VSBYS/CIGS WITH THE SHOWERS AHEAD OF THE WARM FRONT. THERE MAYBE A BRIEF RUMBLE OF THUNDER...BUT SINCE IT IS ISOLATED NO THUNDERSTORMS WERE ADDED TO THE TAF SITES AT THIS TIME. THE BEST CHC OF MVFR CIGS/VSBYS WILL BE BTWN 08Z-14Z. THE CONDITIONS WILL INCREASE BACK TO VFR LEVELS AFTER THE SHOWERS. SCT-BKN CUMULUS AND MID LEVEL CLOUDINESS WILL LINGER IN THE LATE MORNING INTO THE AFTERNOON. THE COLD FRONT AND A PREFRONTAL DISTURBANCE WILL APPROACH LATE IN THE PM INTO THE EARLY EVENING. A VCSH GROUP WAS PLACED IN KGFL/KALB/KPOU/KPSF IN THE 21Z-23Z TIME FRAME. LATER TAF ISSUANCES MAY HAVE TO ADD THUNDERSTORMS IF CONFIDENCE INCREASES. THE WINDS WILL BE LIGHT FROM THE S TO SE AT 5 KTS OR LESS THAN MORNING...THEN INCREASE FROM THE S AT 5-10 KTS IN THE LATE MORNING INTO THE AFTERNOON. OUTLOOK... SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA. SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX. SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. TUESDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA. TUESDAY NIGHT: ISOLATED SHRA. WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION TONIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM WEATHER SUNDAY INTO MONDAY. WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND RH VALUES WILL BE 90 TO 100 PERCENT. WINDS WILL BECOME SOUTHWEST SATURDAY AT 10 TO 15 MPH WITH RH 50 TO 60 PERCENT. RAINFALL TONIGHT AND SATURDAY MAY PRODUCE UP TO A QUARTER TO A THIRD OF INCH. DRY WEATHER IS EXPECTED SUNDAY AND MONDAY. && .HYDROLOGY... THE NEXT CHANCE OF SHOWERS WILL BE TONIGHT INTO SATURDAY...WITH RAINFALL AMOUNTS EXPECTED TO BE AROUND A QUARTER TO A THIRD OF AN INCH. THIS WILL HAVE LITTLE IMPACT ON AREA RIVERS AND STREAMS. ONLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED SATURDAY AFTERNOON AND NIGHT...WITH MAINLY DRY WEATHER EXPECTED FOR SUNDAY. ANOTHER ROUND OF RAIN IS LIKELY LATE MONDAY INTO TUESDAY WITH THE POTENTIAL FOR ANOTHER QUARTER TO THIRD OF AN INCH. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/GJM NEAR TERM...IAA/KL/GJM/LFM SHORT TERM...GJM LONG TERM...KL AVIATION...WASULA FIRE WEATHER...GJM HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS ALBANY NY
139 AM EDT SAT MAY 16 2015 .SYNOPSIS... A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION OVERNIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM WEATHER SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... CLOUD COVER CONTINUES TO LOWER WITH SHOWERS DEVELOPING AND MOVING INTO THE FORECAST AREA AHEAD OF THE APPROACHING WARM FRONT/LOW PRESSURE SYSTEM AND UPPER LEVEL SHORT WAVE TROUGH. SHOWERS HAVE BEEN VERY LIGHT THUS FAR AS THE ATMOSPHERE IS RATHER DAY AS NOTED BY THE VERY DRY LAYER FROM 1000-700 MB ON THE 00Z/ALY SOUNDING. HRRR SHOWS SHOWERS MOVING ACROSS THE AREA THROUGH THE EARLY MORNING HOURS. USED REGIONAL RADARS AND HRRR TO ADJUST POPS. THERE HAS BEEN A FEW LIGHTNING STRIKES ACROSS CENTRAL NEW YORK WHICH LINES UP FAIRLY WELL WITH THE MODELED SHOWALTER INDICES. THE -2 TO ZERO INDICES MOVES ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA...USED THIS AS A GUIDE WHERE TO MENTION SLIGHT CHANCE OF THUNDER FOR THE OVERNIGHT/EARLY MORNING HOURS. OVERALL DID ADJUST TEMPERATURES UP A BIT...HAVE LOWS MAINLY IN THE 50S WITH SOME 40S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS INTO THE NORTHERN BERKSHIRES. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/... THE WARM FRONT WILL CROSS THE REGION SATURDAY MORNING AND THAT SHOULD BRING TO AN END ANY STEADY RAINFALL THAT MAY OCCUR AHEAD OF IT. A WEAK COLD FRONT AND SOME DRIER AIR WILL TRY TO PUSH SOUTHWARD INTO THE REGION SATURDAY AFTN AND NIGHT. IT WILL NOT BE SOUTH OF THE REGION UNTIL EARLY SUNDAY MORNING. AS A RESULT... THERE WILL STILL BE A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS SATURDAY AFTN AND NIGHT...ESPECIALLY AREAS SOUTH OF ALBANY. HAVE GENERALLY FORECAST 20 TO 30 PERCENT POPS FROM THE CAPITAL DISTRICT NORTH DURING SATURDAY AFTERNOON...AND 30 TO 40 PERCENT POPS TO THE SOUTH. THESE POPS CONTINUE TO DECREASE SATURDAY NIGHT WITH MOST OF THE REGION DRY BY SUNRISE SUNDAY. THE DRIER AIR BEHIND THIS WEAK COLD FRONT WILL RESULT IN FAIR AND WARM WEATHER SUNDAY AND SUNDAY NIGHT. HIGHS SATURDAY WILL BE IN THE UPPER 60S AND 70S. LOWS SATURDAY NIGHT GENERALLY 50 TO 60. HIGHS SUNDAY 75 TO 85. LOWS SUNDAY NIGHT IN THE UPPER 40S AND 50S. && .LONG TERM /MONDAY THROUGH FRIDAY/... THE LONG TERM PERIOD WILL BEGIN SOMEWHAT UNSETTLED...BEFORE FAIR WEATHER AND COOLER TEMPERATURES DOMINATE FOR THE BULK OF THE REMAINDER OF THE LONG TERM. FOR MON...A SHARP UPPER LEVEL RIDGE WILL CREST OVER THE REGION BEFORE MOVING OFF THE NEW ENGLAND COAST LATE IN THE DAY. AT THE SFC...A BACKDOOR COLD FRONTAL BOUNDARY SHOULD START OUT ACROSS CENTRAL NYS...POSSIBLY EXTREME WESTERN AREAS OF THE REGION IN THE MORNING. THIS BOUNDARY SHOULD WEAKEN...BEFORE DRIFTING BACK EAST LATER IN THE DAY. ALSO...A MUCH STRONGER COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES REGION. IT APPEARS THAT SHOWERS SHOULD SLOWLY EXPAND EASTWARD ACROSS THE REGION DURING THE DAY. HOWEVER...GIVEN THE SHARPNESS OF THE UPPER LEVEL RIDGE...IT IS QUITE POSSIBLE THAT AREAS EAST OF THE HUDSON RIVER REMAIN DRY THROUGH SUNSET. SO...WILL ONLY GRADUALLY INCREASE POPS INTO THE CHC RANGE FOR WESTERN AREAS...AND MAINLY SLIGHT CHC FOR EASTERN AREAS BY LATE IN THE DAY...WITH MAINLY DRY CONDITIONS FOR ALL AREAS IN THE MORNING. TEMPERATURES WILL BE WARMEST ACROSS THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK RIVER VALLEY...WHERE TEMPS NEAR 80 ARE EXPECTED. ELSEWHERE...A MARINE MODIFIED AIR MASS SHOULD RESULT IN SLIGHTLY COOLER TEMPS FURTHER SOUTH AND EAST...WITH GENERALLY 70S FOR VALLEYS...AND UPPER 60S/LOWER 70S ACROSS HIGHER ELEVATIONS. MON NT-TUE...THE COLD FRONT ACROSS THE GREAT LAKES REGION SHOULD SLOWLY SWING EAST ACROSS THE REGION. THIS SHOULD RESULT IN SOME ROUNDS OF SHOWERS AND POSSIBLE THUNDERSTORMS. THE BEST CHANCE FOR SIGNIFICANT RAINFALL WILL BE ACROSS THE SOUTHERN ADIRONDACKS AND WESTERN MOHAWK VALLEY...WHICH WILL BE CLOSER TO THE PASSING UPPER LEVEL DYNAMICS. SHOWERS MAY TEND TO BECOME MORE SCATTERED FOR AREAS SOUTH AND EAST OF ALBANY. DEPENDING ON THE SPEED OF THE FRONT...SHOWERS MAY TEND TO TAPER OFF FROM NW TO SE TUE AFTERNOON. ALTHOUGH MID/UPPER LEVEL WINDS WILL STRENGTHEN...AT THIS TIME...MID LEVEL LAPSE RATES DO NOT APPEAR VERY STRONG...SO AT LEAST AT THIS TIME RANGE...IT APPEARS THAT THE OVERALL THREAT FOR WIDESPREAD STRONG/SEVERE THUNDERSTORMS SHOULD BE LOW. MON NT/TUE AM MIN TEMPS SHOULD BE MILD...MAINLY IN THE 50S TO LOWER 60S. TUE MAX TEMPS ARE TRICKY...DEPENDING ON HOW MUCH SUN CAN BREAK OUT. ASSUMING CLOUDS REMAIN FAIRLY WIDESPREAD...CURRENT FORECAST MAX TEMPS ARE IN THE 70- 75 RANGE IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. HOWEVER...IF THE FRONT SLOWS DOWN AND SOME BREAKS CAN DEVELOP...MUCH WARMER MAXES COULD OCCUR. TUE NT-FRI...LARGE HIGH PRESSURE SHOULD SLOWLY BUILD ACROSS THE REGION FROM THE GREAT LAKES. MOST LONG TERM GUIDANCE SUGGESTS ANOMALOUSLY COOL MID/UPPER LEVEL HEIGHTS AND CORRESPONDING H925-850 TEMPS. THERE COULD BE SPOTTY SHOWERS/SPRINKLES IN ASSOCIATION WITH THE UPPER LEVEL COLD POOL AND EVEN SOME WEAK LAKE EFFECT PROCESSES FOR TUE NT-WED ACROSS THE SOUTHWEST ADIRONDACKS. OTHERWISE...TEMPS WILL BE QUITE COOL WED...WITH MAXES ONLY REACHING 60-65 IN VALLEYS...AND 50S FOR MOST HIGHER ELEVATIONS...ALTHOUGH SOME OF THE HIGHEST PEAKS OF THE SOUTHERN ADIRONDACKS AND SOUTHERN VT MAY ONLY REMAIN IN THE 40S. OVERNIGHT MIN TEMPS FOR TUE NT/WED AM WILL MAINLY BE IN THE 40S TO LOWER 50S. FOR WED NT/THU AM...MIN TEMPS SHOULD BE EVEN COOLER...WITH 30S ACROSS THE WESTERN ADIRONDACKS...AND 40S ELSEWHERE. THERE COULD BE SOME FROST ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS...WHERE THE GROWING SEASON BEGINS MAY 21. THU AND FRI MAX TEMPS SHOULD WARM SLIGHTLY...WITH LOWER 70S IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. MIN TEMPS FOR THU NT/FRI AM SHOULD FALL INTO THE 40S FOR MOST AREAS. && .AVIATION /05Z SATURDAY THROUGH WEDNESDAY/... A WARM FRONT WILL APPROACH FROM THE SOUTHWEST LATER TONIGHT AND SATURDAY MORNING...PRECEDED AND ACCOMPANIED BY SOME SHOWERS. GENERALLY VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS ENDING 00Z/SUN...DESPITE SOME MID LEVEL CLOUDS AND SHOWERS TONIGHT. DEPENDING ON IF MEASURABLE RAIN ACTUALLY FALLS...THERE COULD BE ENOUGH MOISTENING OF THE BOUNDARY LAYER BETWEEN 10Z- 14Z/SAT TO PRODUCE MVFR CIGS AND VSBYS...BUT THIS APPEARS TO BE A RATHER LOW PROBABILITY. THE BEST CHANCE THAT THIS OCCURS WOULD BE KGFL. AFTER THE WARM FRONT PASSES SAT MORNING...AN ISOLATED SHOWER OR THUNDERSTORM COULD DEVELOP LATER IN THE AFTERNOON. THE BEST CHANCE OF THIS WOULD BE AT KPOU...BUT OVERALL AREAL COVERAGE AND PROBABILITY IS TOO LOW TO MENTION IN TAFS AT THIS TIME. OUTLOOK... SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA. SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX. SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. TUESDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA. TUESDAY NIGHT: ISOLATED SHRA. WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION TONIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM WEATHER SUNDAY INTO MONDAY. WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND RH VALUES WILL BE 90 TO 100 PERCENT. WINDS WILL BECOME SOUTHWEST SATURDAY AT 10 TO 15 MPH WITH RH 50 TO 60 PERCENT. RAINFALL TONIGHT AND SATURDAY MAY PRODUCE UP TO A QUARTER TO A THIRD OF INCH. DRY WEATHER IS EXPECTED SUNDAY AND MONDAY. && .HYDROLOGY... THE NEXT CHANCE OF SHOWERS WILL BE TONIGHT INTO SATURDAY...WITH RAINFALL AMOUNTS EXPECTED TO BE AROUND A QUARTER TO A THIRD OF AN INCH. THIS WILL HAVE LITTLE IMPACT ON AREA RIVERS AND STREAMS. ONLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED SATURDAY AFTERNOON AND NIGHT...WITH MAINLY DRY WEATHER EXPECTED FOR SUNDAY. ANOTHER ROUND OF RAIN IS LIKELY LATE MONDAY INTO TUESDAY WITH THE POTENTIAL FOR ANOTHER QUARTER TO THIRD OF AN INCH. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/GJM NEAR TERM...IAA/KL/GJM/LFM SHORT TERM...GJM LONG TERM...KL AVIATION...KL FIRE WEATHER...GJM HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
400 PM EDT SAT MAY 16 2015 .SYNOPSIS... A WEAK COLD FRONT IS FORECAST TO MOVE THROUGH OUR AREA SUNDAY INTO SUNDAY NIGHT. THE NEXT LOW PRESSURE SYSTEM CURRENTLY NEAR THE ROCKIES IS EXPECTED TO PROGRESS EASTWARD ACROSS THE GREAT LAKES REGION, SENDING A COLD FRONT THROUGH OUR AREA TUESDAY INTO TUESDAY NIGHT. HIGH PRESSURE WILL THEN GRADUALLY BUILD EAST INTO OUR REGION FROM MIDWEEK THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A DISORGANIZED AREA OF CONVECTION HAS BEEN STEADILY MOVING EASTWARD THIS AFTERNOON THROUGH CENTRAL PENNSYLVANIA WHERE BULK SHEAR VALUES ARE LESS THAN 25 KNOTS. AS THIS LINE MOVES CLOSER TO OUR REGION IT WILL BEGIN TO INGEST MORE UNSTABLE AIR WITH BETTER BULK SHEAR IN PLACE ALLOWING FOR SOMEWHAT MORE ORGANIZATION AND LONGEVITY. EXPECTING THESE STORMS TO MOVE INTO OUR WESTERN ZONES OVER THE NEXT COUPLE OF HOURS. FORECAST SOUNDINGS STILL SHOW LONG THIN CAPE PROFILES WITH SOME DRY AIR IN THE MID-LEVELS. LATEST RUC DCAPE VALUES ARE AROUND 800 TO 1000J/KG WITH STRONG TO ISOLATED SEVERE WIND GUSTS THE MAIN THREAT TO ANY OF THESE STORMS. VERY HEAVY RAINFALL IS ALSO EXPECTED AS THEY PUSH THROUGH WITH PWAT VALUES RUNNING AROUND THE 99TH PERCENTILE FOR MID-MAY. THIS COUPLED WITH VERY DRY CONDITIONS SHOULD ALLOW FOR MORE EFFICIENT RUNOFF TO OCCUR WITH PONDING ON ROADWAYS AND POOR DRAINAGE LOCATIONS. FORTUNATELY THE MEAN STEERING FLOW OF THESE STORMS IS ALLOWING THEM TO MOVE RELATIVELY QUICKLY, AROUND 30 KNOTS TOWARDS THE EAST. ONCE THESE STORMS EITHER PUSH OFF THE COAST OF BECOME ELEVATED IN NATURE WITH THE LOSS OF DAYTIME HEATING MORE SCATTERED SHOWER ACTIVITY IS EXPECTED THROUGH MOST OF THE LATE EVENING HOURS BEFORE WE DRY OUT SOME. VERY MUGGY CONDITIONS WILL EXIST TONIGHT WITH AMPLE MOISTURE IN THE LOW-LEVELS. PATCHY FOG IS POSSIBLE AS THE WINDS DECOUPLE AND BECOME LIGHT AND VARIABLE. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... ALMOST A CARBON COPY OF SATURDAY IN TERMS OF THE SHOWER/CONVECTION THREAT DURING THE DAY...MAYBE NOT AS WIDESPREAD. WE WILL HAVE THE MOISTURE IN PLACE WITH ANOTHER WELL ABOVE AVERAGE TEMPERATURE FORECAST. ONE OF THE BIGGEST QUESTIONS IS THE POTENTIAL LACK OF BETTER SURFACE BASED INSTABILITY WITH A PERSISTENT STRATOCU DECK IN PLACE...MAYBE SOME BREAKS POSSIBLE AS THE WINDS VEER MORE TOWARDS THE WEST DURING THE AFTERNOON. TEMPERATURES MAY END UP A TAD COOLER WITH THE AMOUNT OF MOISTURE TRAPPED UNDER THE LOW-LEVEL INVERSION, BUT A WARMER STARTING POINT SHOULD YIELD LOW-80S. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... DESPITE STARTING OUT UNDER THE AXIS OF AN UPPER LEVEL SHORTWAVE RIDGE...THERE LOOK TO BE PLENTY OF OPPORTUNITIES FOR RAIN, AT LEAST TO BEGIN THE LONG TERM PERIODS. SUNDAY NIGHT...SHORTWAVE RIDGE PIVOTS OVERHEAD, WHILE AT THE SURFACE, THE WEAK COLD FRONT CONTINUES TO SLIDE SOUTH OVER THE REGION. THE COMBINATION OF MID AND UPPER LEVEL SUBSIDENCE, ALONG WITH A NOCTURNAL INVERSION SHOULD HELP TO SUPPRESS OVERNIGHT CONVECTION. THEREFORE, STAYED CLOSE TO THE PREVIOUS FORECAST WITH PRECIP CHANCES DROPPING FROM 20 TO 50 PERCENT IN THE EVENING TO 10 TO 20 PERCENT AFTER MIDNIGHT. MONDAY INTO TUESDAY...SURFACE LOW STILL EXPECTED TO TRACK ACROSS THE GREAT LAKES REGION, WHILE IN THE MID AND UPPER LEVELS, THE RIDGE SHIFTS OFF SHORE. PERSISTENT EASTERLY FLOW ON MONDAY RESULTING IN LOW CLOUDS, MAY LIMIT SURFACE BASED INSTABILITY, BUT ELEVATED INSTABILITY IS POSSIBLE. THEREFORE, INCLUDED THUNDERSTORM MENTION ACROSS THE REGION, THOUGH WOULD EXPECT MOSTLY STRATIFORM RAIN OR SHOWERS ON MONDAY. ON TUESDAY HOWEVER, WINDS SHIFT TO SOUTHERLY AND SOUTHWESTERLY AS A PRE FRONTAL TROUGH ARRIVES TUESDAY AFTERNOON. THE COLD FRONT SHOULD ARRIVE TUESDAY EVENING/OVERNIGHT. THERE ALSO APPEARS TO BE SUBSTANTIAL SPEED SHEAR (20 TO 35 KT) THROUGH THE DAY. THERE ARE A FEW POTENTIAL LIMITATIONS TO CONVECTION THOUGH, PRIMARILY MEAGER LAPSE RATES ABOVE THE BOUNDARY LAYER. PRECIPITABLE WATER VALUES SHOULD BE WELL ABOVE NORMAL, AND THE WARM CLOUD LAYER IS EXPECTED TO BE QUITE DEEP. AND WHILE FORECAST STORM MOTIONS SHOULD BE AROUND 20 TO 25 KT, THERE IS THE POTENTIAL FOR TRAINING STORMS IF THE PRE FRONTAL TROUGH SERVES AS A FOCUS FOR CONVECTIVE INITIATION. THEREFORE, WILL ADD MENTION IN THE HWO OF HEAVY RAIN THREAT. WEDNESDAY THROUGH SATURDAY...FRONT CLEARS OUT QUICKLY BY EARLY WEDNESDAY MORNING, LEAVING THE REGION UNDER A MOSTLY DRY PATTERN AS A SURFACE HIGH IS EXPECTED TO BUILD IN OVER MUCH OF THE NORTHEAST. A FEW CAVEATS, HOWEVER. FIRST, A PAIR OF SHORTWAVE TROUGHS ON THE BACK SIDE OF THE DEPARTING UPPER LEVEL TROUGH MAY DIG OVER OUR REGION, BUT THE TIMING OF THE TROUGHS IS UNCERTAIN, AND LOW LEVEL MOISTURE MAY BE LIMITED WITH PERSISTENT DOWN SLOPE FLOW. SECOND, BOTH THE GFS AND ECMWF SHOW A COASTAL LOW DEVELOPING OVER THE CAROLINA/VIRGINIA COASTS BY FRIDAY. DEPENDING ON HOW FAR NORTH THIS DEVELOPS, IT COULD RESULT IN PRECIP ACROSS THE DELMARVA PENINSULA AND FAR SOUTHERN NJ. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THIS EVENING - TONIGHT...MOSTLY VFR WITH SOME MVFR/IFR SHOWERS AND THUNDERSTORMS POSSIBLE THIS EVENING. STILL THINKING MOST OF THE THUNDER ACTIVITY OCCURS AROUND 20 TO 00Z THIS EVENING FROM WEST TO EAST. AFTERWARDS LINGERING SHOWERS ARE POSSIBLE ALLOWING CONDITIONS TO DETERIORATE TOWARDS MVFR AFTER MIDNIGHT...LOW CONFIDENCE ON MVFR CONDITIONS TONIGHT. SUNDAY...ANY MVFR RESTRICTIONS SHOULD LIFT/BURN OFF BY LATE MORNING ALLOWING FOR MORE VFR CONDITIONS. CONTINUED SOUTHWESTERLY FLOW WILL KEEP MOISTURE STREAMING INTO THE REGION SO WE MAY NOT BREAK OUT MUCH DURING THE DAY. MORE SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE DURING THE AFTERNOON HOURS. OUTLOOK... SUNDAY NIGHT INTO MONDAY...WIDESPREAD MVFR AND LOCALIZED IFR CONDITIONS WITH LOW CLOUDS AND SHOWERS POSSIBLE FOR MUCH OF THE PERIOD. CHANCE FOR THUNDERSTORMS MONDAY AFTERNOON AND EVENING. TUESDAY...THUNDERSTORMS LIKELY. MVFR AND LOCALIZED IFR CONDITIONS EXPECTED TO CONTINUE. WEDNESDAY AND THURSDAY...VFR CONDITIONS EXPECTED. && .MARINE... TONIGHT - SUNDAY...SUB-SCA CONDITIONS ACROSS THE WATERS EXPECTED. SOUTHERLY FLOW WILL CONTINUE THROUGH SUNDAY ALLOWING SEAS TO BUILD UPWARDS OF 4 FEET BY SUNDAY AFTERNOON. WITH COLDER THAN NORMAL WATER TEMPERATURES AND A WARMER AIRMASS IN PLACE EXPECTING THE AMOUNT OF MIXING TO BE KEPT TO A MINIMUM...LESS THAN 20 KNOTS. OUTLOOK... MONDAY AND TUESDAY...SUB SCA CONDITIONS LIKELY. HOWEVER, A FEW GUSTS ABOVE 20 KT ARE POSSIBLE ON MONDAY ON THE OCEAN WATERS, AND HIGHER GUSTS WILL BE POSSIBLE IN THE VICINITY OF ANY THUNDERSTORMS. WEDNESDAY AND THURSDAY...WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA. && .RIP CURRENTS... THE RISK FOR RIP CURRENTS IS BORDERLINE LOW TO MODERATE FOR THE NJ COAST ON SATURDAY AFTERNOON. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...JOHNSON NEAR TERM...HEAVENER SHORT TERM...HEAVENER LONG TERM...JOHNSON AVIATION...HEAVENER/JOHNSON MARINE...HEAVENER/JOHNSON RIP CURRENTS...O`HARA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
228 PM EDT SAT MAY 16 2015 .SYNOPSIS... 18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN AMPLIFIED UPPER LEVEL PATTERN OVER THE CONUS TODAY. DEEP AND POTENT UPPER TROUGH IS SPINNING OVER THE INTERMOUNTAIN WEST/WESTERN PLAINS...WITH DOWNSTREAM STRONG RIDGING ALOFT OVER THE EASTERN THIRD OF THE NATION. WV IMAGERY SHOWS A STRONG SHORTWAVE ROUNDING THE BASE OF THE WESTERN TROUGH AND ABOUT TO EJECT NORTHEASTWARD OVER THE CENTRAL PLAINS. THIS ENERGY IS FORECAST TO BRING A POTENTIAL SIGNIFICANT SEVERE WEATHER OUTBREAK TO PARTS OF TEXAS/OK/KS LATER TODAY. WHILE THIS WEATHER SYSTEM AND ITS ASSOCIATED ORGANIZED SEVERE WEATHER THREAT WILL STAY WELL TO OUR NORTHWEST THIS WEEKEND...WE IN WEST-CENTRAL AND SOUTHWEST FLORIDA WILL BE DEALING WITH MORE OF OUR OWN LATE DAY SEA-BREEZE STORMS. MORE INFO ON OUR THUNDERSTORM THREAT IN THE SHORT TERM DISCUSSION BELOW. AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO THE WEST INTO THE GA/CAROLINA COAST...PROVIDING OUR REGION WITH A GENERAL EAST TO SOUTHEAST LOW LEVEL FLOW. SIMILAR TO PREVIOUS DAYS...THIS EASTERLY SYNOPTIC FLOW WILL FAVOR THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA WEST COAST SEA-BREEZE DUE TO THE ADDED CONVERGENCE AND EVENTUAL ARRIVAL/COLLISION OF THE EAST COAST SEA- BREEZE BOUNDARY. && .SHORT TERM... REST OF TODAY...WITHIN THE LARGE SCALE PRESSURE GRADIENT ON THE SOUTHERN PERIPHERY OF THE ATLANTIC RIDGE TO OUR NORTH...WE CAN ANALYZE A WEAK INVERTED TROUGH/CONVERGENCE ZONE ALONG THE SOUTHEAST FL COAST. SCATTERED SHOWERS BEGAN MIGRATING WESTWARD FROM THIS FEATURE INTO THE SOUTH-CENTRAL ZONES (HIGHLANDS/HARDEE/DESOTO) DURING THE EARLY AFTERNOON...AND NOW MOVING OVER TOWARD THE PUNTA GORDA/FORT MYERS AREA. SO...A FEW SHOWERS AROUND FOR THE SOUTHERN ZONES FROM THIS ACTIVITY THROUGH MID AFTERNOON...BUT THE MAIN CONVECTIVE DEVELOPMENT IS STILL NOT EXPECTED UNTIL LATER IN THE AFTERNOON/EARLY EVENING HOURS. BEFORE THE EXPECTED CONVECTIVE BURST...MUCH OF THE REGION FROM THE I-4 CORRIDOR NORTHWARD WILL SEE A MIX OF SUN AND CLOUDS WITH TEMPERATURES INTO THE 80S. FORECASTING SEA-BREEZE THUNDERSTORMS IS NEVER A PERFECT SCIENCE... BUT HERE IS THE BREAKDOWN LEADING TO THE CURRENT FORECAST. WE START WITH THE SYNOPTIC LOW LEVEL (1000-700MB) FLOW...WHICH TODAY IS MODERATE FROM THE EAST/SOUTHEAST. THIS FLOW REGIME DURING THE WARM SEASON FAVORS LATE DAY THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA WEST COAST...WITH DRIER CONDITIONS BY LATE AFTERNOON FOR THE FLORIDA EAST COAST. THE WEST COAST IS FAVORED DUE TO THE ENHANCED CONVERGENCE OF THE LARGE SCALE FLOW HEADING WESTWARD...AND THE WEST COAST SEA-BREEZE TRYING TO MOVE EAST. EVENTUALLY THE EAST COAST SEA- BREEZE...SPED ALONG BY THE LARGE SCALE FLOW ARRIVES AT THE I-75 CORRIDOR AND FURTHER ENHANCES THE LOW LEVEL FOCUS/CONVERGENCE. ALOFT...THERE IS NOT REALLY ANY SIGNIFICANT HOSTILE LAYER TOWARD DEEP CONVECTION...WITH MINIMUM THETAE VALUES NO LOWER THAN AROUND 320K (FAIRLY TYPICAL FOR MID MAY). THE CURRENT FORECAST FAVORS THE HIGHEST RAIN CHANCES LATE AFTERNOON/EVENING FROM TAMPA BAY SOUTHWARD DUE TO THE FACT THAT THE FLOW JUST ALOFT OFF THE SURFACE SEEMS TO BE A BIT STRONGER FOR THE NATURE COAST...AND IS BORDERLINE STRONG ENOUGH TO PREVENT AN ORGANIZED SEA-BREEZE...OR TO KEEP IT SUPPRESSED JUST OFFSHORE. LIGHTER FLOW FURTHER SOUTH SHOULD ALLOW SOME INLAND PENETRATION OF THE SEA-BREEZE CIRCULATION SO THAT THE MORE EFFICIENT LOW LEVEL FOCUS ZONE TO ENHANCE LIFT APPEARS TO SET UP FROM PASCO/PINELLAS COUNTIES SOUTHWARD. THERE IS ACTUALLY VERY GOOD AGREEMENT AMONG THE HIRES CONVECTION ALLOWING GUIDANCE FROM NCEP AND LOCAL RUNS TO SUPPORT THIS SCENARIO. IN FACT...THE LAST FEW RUNS OF THE HRRR HAVE BEEN FOCUSING MAINLY FROM MANATEE COUNTY SOUTHWARD. SINCE...THE HIRES GUIDANCE ARE SUBJECT TO INFLUENCE FROM THEIR OWN EARLIER CONVECTION...AND THE PARAMETERIZED MODELS ARE STILL SHOWING DEVELOPMENT A BIT FURTHER NORTH...HAVE INCLUDED THE TAMPA BAY/PASCO AREA IN THE LIKELY RAIN/THUNDER CHANCES. WILL SEE HOW ALL THIS WORKS OUT AS WE GET LATER INTO THE DAY...BUT BASED ON ALL AVAILABLE INFO AND PATTERN RECOGNITION...FEEL THIS IS THE BEST FORECAST. HAVE ALSO BEEN FAIRLY IMPRESSED WITH THE GENERAL UPDRAFT VELOCITY VALUES OUT OF THE HRRR FOR LATER TODAY. PEAK VALUES ALONG THE SUN COAST TO THE SOUTH OF TAMPA BAY HAVE BEEN IN THE 14-18M/S RANGE...WHICH IS FAIRLY SUBSTANTIAL FOR LOW SHEAR PULSE CONVECTION. WITH THIS IN MIND WILL NEED TO BE MINDFUL OF PRECIP LOADING AND DOWNBURST POTENTIAL WITH STRONGER CELLS. ALSO...THE POTENTIAL FOR SOME EFFICIENT LIGHTNING PRODUCERS IS ALSO THERE. WHAT IS LEFT OF THE STORMS PUSH OFFSHORE INTO THE COASTAL WATERS BY LATE EVENING...FOLLOWED BY A GENERALLY QUIET...DRY AND SEASONABLY WARM OVERNIGHT PERIOD. SUNDAY... WE SEE ONE MORE DAY WITH THIS BROKEN RECORD PATTERN OF EASTERLY SYNOPTIC FLOW BEFORE THE PATTERN BEGINS TO TRANSITION. ONE THING ADVERTISED BY THE CURRENT MODEL SUITE...IS A MORE UNIFORM LIGHT FLOW ABOVE THE SURFACE FOR THE AFTERNOON HOURS...RESULTING IN A MORE UNIFORM ORGANIZATION TO THE SEA-BREEZE ALONG OUR COASTS. THEREFORE...AFTER A QUIET MORNING AND EARLY AFTERNOON...YET ANOTHER ROUND OF LATE DAY STORMS IS ANTICIPATED ALONG THE I-75 CORRIDOR. AS IT STANDS NOW...APPEARS WE SHOULD SEE A SCATTERING OF SHOWERS/STORMS PROGRESS FROM EAST TO WEST ACROSS THE FORECAST AREA ALONG THE EAST COAST SEA BREEZE DURING THE EARLY/MID AFTERNOON...WITH CONVECTION RAMPING UP TO NUMEROUS THUNDERSTORMS ALONG AND INSIDE THE I-75 CORRIDOR AFTER AROUND 400 PM. && .LONG TERM (MONDAY THROUGH NEXT SATURDAY)...ALOFT - RIDGING GENERALLY DOMINATES THE GULF AND FL...ALTHOUGH IT BRIEFLY WEAKENS AND DRIFTS BACK WEST MID-WEEK...AS A COUPLE OF LOWS/TROUGHS TRAVERSES THE NORTHERN TIER OF STATES. AT THE SURFACE - HIGH PRESSURE WAS OVER CENTRAL CANADA WITH A FRONT THAT ARCED FROM THE UPPER GREAT LAKES THROUGH THE SOUTHERN HIGH PLAINS THEN BACK UP THROUGH THE PACIFIC NORTHWEST...THIS HIGH DROPS DOWN INTO THE MID-MISSISSIPPI VALLEY THEN TRACKS EAST WITH THE FRONT SAGGING IN ALONG THE AL/GA/FL BORDER BY THE END OF THE WORK WEEK AND IN ACROSS NORTHERN FRI SAT. ATLANTIC HIGH PRESSURE...WITH AN AXIS INITIALLY ALONG THE NORTHERN FL LINE...SINKS SOUTH WITH IT/S AXIS SETTLING IN ACROSS CENTRAL FL THEN SOUTH FL. THE FORECAST PHILOSOPHY WILL BE BASED ON A GENERALLY MOIST AIRMASS IN PLACE...WITH MODEL PWAT VALUES RUNNING ABOVE 1.6 INCHES AND UP TO NEAR 2.0 INCHES AT TIMES. THE EXCEPTION MAY BE SAT WHEN THE FRONT SAGS INTO NORTH FL WITH SOME DRIER AIR BEHIND IT. HOWEVER...AT THIS POINT IN THE FORECAST THE GFS BRINGS THE FRONT INTO FL WHILE THE ECMWF HOLDS IT ON THE STATE LINE OR ABOVE. THE SURFACE RIDGE AXIS TRACKING SOUTH WITH GRADUALLY TRANSITIONING FLOW FROM SOUTHEASTERLY WITH SEA BREEZES TO WESTERLY BY FRI. BUT AGAIN...BASED ON THE FASTER GFS...FLOW SHIFTS AROUND TO NORTHEASTERLY BY THE END OF THE PERIOD. SHOWERS AND THUNDERSTORMS WILL BE IN THE SCATTERED RANGE WITH THE HIGHEST COVERAGE SWITCHING FROM COASTAL TO MORE INLAND THROUGH THE WORK WEEK. ABOVE NORMAL TEMPERATURES WILL CONTINUE. && .AVIATION... CONDITIONS ARE QUIET WITH PREVAILING VFR ONGOING LATE THIS MORNING ACROSS WEST CENTRAL AND SW FLORIDA. HOWEVER...THESE CALM CONDITIONS ARE NOT EXPECTED TO LAST THE REMAINDER OF THE DAY. SIMILAR TO PREVIOUS DAYS...RAPID THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG THE I-75 CORRIDOR AFTER 20Z...WITH STORMS THEN PUSHING SLOWLY TO THE WEST. A PERIOD OF IFR OR LOWER VIS/CIGS ALONG WITH GUSTY WINDS AND FREQUENT LIGHTING IS POSSIBLE FOR ANY TERMINAL LATER TODAY. WILL ADD THUNDER TEMPO GROUPS WITH 18Z PACKAGE. && .MARINE... A GENERAL EAST TO SOUTHEAST WINDS FLOW WILL REMAIN IN PLACE THROUGH SUNDAY WITH WINDS TURNING ONSHORE AT THE COAST EACH AFTERNOON AS THE SEA BREEZE DEVELOPS. THUNDERSTORMS ARE EXPECTED TO RAPIDLY DEVELOP NEAR THE COAST DURING THE LATE AFTERNOON AND EVENING HOUR BOTH TODAY AND SUNDAY...THEN PUSH OFFSHORE DURING THE NIGHTTIME HOURS. BOATERS ENJOYING THE COASTAL WATERS OF THE FLORIDA WEST COAST SHOULD KEEP AND EYE TO THEIR EAST DURING THE LATE DAY HOURS THIS WEEKEND...AND BE PREPARED TO SEEK SAFE HARBOR SHOULD THREATENING WEATHER ADVANCE. HEADING THROUGH THE UPCOMING WORK WEEK...WINDS WILL SHIFT MORE WESTERLY...KEEPING MOST OF THE THUNDERSTORM ACTIVITY INLAND. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. LATE AFTERNOON AND EVENING THUNDERSTORMS WILL BE MOST NUMEROUS NEAR THE COAST FROM TAMPA BAY SOUTHWARD TODAY...THEN ALONG THE ENTIRE COASTAL I-75 CORRIDOR FOR LATE SUNDAY. THE PATTERN WILL THEN BEGIN TO TRANSITION TO ONE SUPPORTING LATE DAY STORMS FURTHER INLAND...WITH DRIER CONDITIONS NEAR THE COAST. FOG IMPACT...NO SIGNIFICANT FOG IS EXPECTED FOR THE NEXT FEW DAYS...BUT LATE NIGHT PATCHY GROUND FOG COULD DEVELOP IN AREAS THAT SEE RAIN DURING THE EVENING HOURS. && .PRELIMINARY POINT TEMPS/POPS... TPA 73 89 73 89 / 30 60 50 20 FMY 72 90 72 90 / 40 60 30 30 GIF 72 90 71 91 / 10 40 10 20 SRQ 72 87 72 88 / 40 60 50 20 BKV 69 90 69 90 / 20 60 40 30 SPG 75 89 75 89 / 40 60 50 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SHORT TERM/AVIATION/FIRE WEATHER/MARINE...14/MROCZKA LONG TERM/DECISION SUPPORT...09/RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1130 AM EDT SAT MAY 16 2015 .SYNOPSIS... 16Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN AMPLIFIED UPPER LEVEL PATTERN OVER THE CONUS TODAY. DEEP AND POTENT UPPER TROUGH IS SPINNING OVER THE INTERMOUNTAIN WEST/WESTERN PLAINS...WITH DOWNSTREAM STRONG RIDGING ALOFT OVER THE EASTERN THIRD OF THE NATION. WV IMAGERY SHOWS A STRONG SHORTWAVE ROUNDING THE BASE OF THE WESTERN TROUGH AND ABOUT TO EJECT NORTHEASTWARD OVER THE CENTRAL PLAINS. THIS ENERGY IS FORECAST TO BRING A POTENTIAL SIGNIFICANT SEVERE WEATHER OUTBREAK TO PARTS OF TEXAS/OK/KS LATER TODAY. WHILE THIS WEATHER SYSTEM AND ITS ASSOCIATED ORGANIZED SEVERE WEATHER THREAT WILL STAY WELL TO OUR NORTHWEST THIS WEEKEND...WE IN WEST- CENTRAL AND SOUTHWEST FLORIDA WILL BE DEALING WITH MORE OF OUR OWN LATE DAY SEA-BREEZE STORMS. MORE INFO ON OUR THUNDERSTORM THREAT IN THE SHORT TERM DISCUSSION BELOW. ALREADY SEEING RAPID CUMULUS FIELD DEVELOPMENT ACROSS MUCH OF THE PENINSULA LATE THIS MORNING...AND THIS SCT-BKN CLOUD FIELDS SHOULD INVADE ALL OF OUR SKIES INTO THE EARLY AFTERNOON HOURS. AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO THE WEST INTO THE GA/CAROLINA COAST...PROVIDING OUR REGION WITH A GENERAL EAST TO SOUTHEAST LOW LEVEL FLOW. SIMILAR TO PREVIOUS DAYS...THIS EASTERLY SYNOPTIC FLOW WILL FAVOR THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA WEST COAST SEA-BREEZE DUE TO THE ADDED CONVERGENCE AND EVENTUAL ARRIVAL/COLLISION OF THE EAST COAST SEA- BREEZE BOUNDARY. && .SHORT TERM (REST OF TODAY THROUGH SUNDAY)... REST OF TODAY... WITHIN THE LARGE SCALE PRESSURE GRADIENT ON THE SOUTHERN PERIPHERY OF THE ATLANTIC RIDGE TO OUR NORTH...WE CAN ANALYZE A WEAK INVERTED TROUGH/CONVERGENCE ZONE ALONG THE SOUTHEAST FL COAST. WILL SEE A SCATTERING OF SHOWERS BEGIN TO MIGRATE WESTWARD FROM THIS FEATURE INTO THE SOUTH-CENTRAL ZONES (HIGHLANDS/HARDEE/DESOTO) DURING THE EARLY AFTERNOON...AND EVENTUALLY OVER TOWARD THE PUNTA GORDA/FORT MYERS AREA. MAY SEE A BRIEF SHOWER FROM THIS ACTIVITY...BUT THE MAIN CONVECTIVE DEVELOPMENT IS NOT EXPECTED UNTIL LATER IN THE AFTERNOON/EARLY EVENING HOURS. BEFORE THE EXPECTED CONVECTIVE BURST...MUCH OF THE REGION WILL SEE A MIX OF SUN AND CLOUDS WITH TEMPERATURES CLIMBING THROUGH THE 80S. FORECASTING SEA-BREEZE THUNDERSTORMS IS NEVER A PERFECT SCIENCE... BUT HERE IS THE BREAKDOWN LEADING TO THE CURRENT FORECAST. WE START WITH THE SYNOPTIC LOW LEVEL (1000-700MB) FLOW...WHICH TODAY IS MODERATE FROM THE EAST/SOUTHEAST. THIS FLOW REGIME DURING THE WARM SEASON FAVORS LATE DAY THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA WEST COAST...WITH DRIER CONDITIONS BY LATE AFTERNOON FOR THE FLORIDA EAST COAST. THE WEST COAST IS FAVORED DUE TO THE ENHANCED CONVERGENCE OF THE LARGE SCALE FLOW HEADING WESTWARD...AND THE WEST COAST SEA-BREEZE TRYING TO MOVE EAST. EVENTUALLY THE EAST COAST SEA- BREEZE...SPED ALONG BY THE LARGE SCALE FLOW ARRIVES AT THE I-75 CORRIDOR AND FURTHER ENHANCES THE LOW LEVEL FOCUS/CONVERGENCE. ALOFT...THERE IS NOT REALLY ANY SIGNIFICANT HOSTILE LAYER TOWARD DEEP CONVECTION...WITH MINIMUM THETAE VALUES NO LOWER THAN AROUND 320K (FAIRLY TYPICAL FOR MID MAY). THE CURRENT FORECAST FAVORS THE HIGHEST RAIN CHANCES LATE AFTERNOON/EVENING FROM TAMPA BAY SOUTHWARD DUE TO THE FACT THAT THE FLOW JUST ALOFT OFF THE SURFACE SEEMS TO BE A BIT STRONGER FOR THE NATURE COAST...AND IS BORDERLINE STRONG ENOUGH TO PREVENT AN ORGANIZED SEA-BREEZE...OR TO KEEP IT SUPPRESSED JUST OFFSHORE. LIGHTER FLOW FURTHER SOUTH SHOULD ALLOW SOME INLAND PENETRATION OF THE SEA-BREEZE CIRCULATION SO THAT THE MORE EFFICIENT LOW LEVEL FOCUS ZONE TO ENHANCE LIFT APPEARS TO SET UP FROM PASCO/PINELLAS COUNTIES SOUTHWARD. THERE IS ACTUALLY VERY GOOD AGREEMENT AMONG THE HIRES CONVECTION ALLOWING GUIDANCE FROM NCEP AND LOCAL RUNS TO SUPPORT THIS SCENARIO. IN FACT...THE LAST FEW RUNS OF THE HRRR HAVE BEEN FOCUSING MAINLY FROM MANATEE COUNTY SOUTHWARD. SINCE...THE HIRES GUIDANCE ARE SUBJECT TO INFLUENCE FROM THEIR OWN EARLIER CONVECTION...AND THE PARAMETERIZED MODELS ARE STILL SHOWING DEVELOPMENT A BIT FURTHER NORTH...HAVE INCLUDED THE TAMPA BAY/PASCO AREA IN THE LIKELY RAIN/THUNDER CHANCES. WILL SEE HOW ALL THIS WORKS OUT AS WE GET LATER INTO THE DAY...BUT BASED ON ALL AVAILABLE INFO AND PATTERN RECOGNITION...FEEL THIS IS THE BEST FORECAST. HAVE ALSO BEEN FAIRLY IMPRESSED WITH THE GENERAL UPDRAFT VELOCITY VALUES OUT OF THE HRRR FOR LATER TODAY. PEAK VALUES SOUTH OF TAMPA BAY HAVE BEEN IN THE 15-20M/S RANGE...WHICH IS FAIRLY SUBSTANTIAL FOR LOW SHEAR PULSE CONVECTION. WITH THIS IN MIND WILL NEED TO BE MINDFUL OF PRECIP LOADING AND DOWNBURST POTENTIAL WITH STRONGER CELLS. ALSO...THE POTENTIAL FOR SOME EFFICIENT LIGHTNING PRODUCERS IS ALSO THERE. WHAT IS LEFT OF THE STORMS PUSH OFFSHORE INTO THE COASTAL WATERS BY LATE EVENING...FOLLOWED BY A GENERALLY QUIET...DRY AND SEASONABLY WARM OVERNIGHT PERIOD. SUNDAY... WE SEE ONE MORE DAY WITH THIS BROKEN RECORD PATTERN OF EASTERLY SYNOPTIC FLOW. ONE THING ADVERTISED BY THE CURRENT MODEL SUITE...IS A MORE UNIFORM LIGHT FLOW ABOVE THE SURFACE FOR THE AFTERNOON HOURS...RESULTING IN A MORE UNIFORM ORGANIZATION TO THE SEA-BREEZE ALONG OUR COASTS. THEREFORE...AFTER A QUIET MORNING AND EARLY AFTERNOON...YET ANOTHER ROUND OF LATE DAY STORMS IS ANTICIPATED ALONG THE I-75 CORRIDOR. AS IT STANDS NOW...APPEARS WE SHOULD SEE A SCATTERING OF SHOWERS/STORMS PROGRESS FROM EAST TO WEST ACROSS THE FORECAST AREA ALONG THE EAST COAST SEA BREEZE DURING THE EARLY/MID AFTERNOON...WITH CONVECTION RAMPING UP TO NUMEROUS THUNDERSTORMS ALONG AND INSIDE THE I-75 CORRIDOR AFTER AROUND 400 PM. THE SYNOPTIC PATTERN FINALLY BEGINS TO TRANSITION TO A MORE WESTERLY FLOW REGIME EARLY NEXT WEEK...WHICH SHOULD SHIFT THE HIGHER RAIN CHANCES AWAY FROM THE COAST TOWARD THE INLAND AREAS/FL EAST COAST. && .AVIATION... CONDITIONS ARE QUIET WITH PREVAILING VFR ONGOING LATE THIS MORNING ACROSS WEST CENTRAL AND SW FLORIDA. HOWEVER...THESE CALM CONDITIONS ARE NOT EXPECTED TO LAST THE REMAINDER OF THE DAY. SIMILAR TO PREVIOUS DAYS...RAPID THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG THE I-75 CORRIDOR AFTER 20Z...WITH STORMS THEN PUSHING SLOWLY TO THE WEST. A PERIOD OF IFR OR LOWER VIS/CIGS ALONG WITH GUSTY WINDS AND FREQUENT LIGHTING IS POSSIBLE FOR ANY TERMINAL LATER TODAY. WILL ADD THUNDER TEMPO GROUPS WITH 18Z PACKAGE. && .MARINE... A GENERAL EAST TO SOUTHEAST WINDS FLOW WILL REMAIN IN PLACE THROUGH SUNDAY WITH WINDS TURNING ONSHORE AT THE COAST EACH AFTERNOON AS THE SEA BREEZE DEVELOPS. THUNDERSTORMS ARE EXPECTED TO RAPIDLY DEVELOP NEAR THE COAST DURING THE LATE AFTERNOON AND EVENING HOUR BOTH TODAY AND SUNDAY...THEN PUSH OFFSHORE DURING THE NIGHTIME HOURS. BOATERS ENJOYING THE COASTAL WATERS OF THE FLORIDA WEST COAST SHOULD KEEP AND EYE TO THEIR EAST DURING THE LATE DAY HOURS THIS WEEKEND...AND BE PREPARED TO SEEK SAFE HARBOR SHOULD THREATENING WEATHER ADVANCE. HEADING THROUGH THE UPCOMING WORK WEEK...WINDS WILL SHIFT MORE WESTERLY...KEEPING MOST OF THE THUNDERSTORM ACTIVITY INLAND. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... TPA 89 73 89 73 / 60 30 60 20 FMY 91 72 90 72 / 70 40 60 20 GIF 90 72 90 71 / 30 10 50 10 SRQ 88 72 88 72 / 70 40 60 20 BKV 90 70 89 69 / 50 20 60 10 SPG 89 75 89 75 / 60 40 60 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/AVIATION/FIRE WX...MROCZKA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1011 PM EDT SUN MAY 17 2015 .SYNOPSIS... DRY WEATHER WILL CONTINUE THROUGH TONIGHT WITH HIGH PRESSURE AT THE SURFACE AND ALOFT. THE CHANCE FOR RAIN WILL INCREASE MONDAY AFTERNOON AHEAD OF AN APPROACHING COLD FRONT SCHEDULED TO CROSS THE AREA TUESDAY. TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE WEEK. && .NEAR TERM /UNTIL 7 AM MONDAY MORNING/... DRY WEATHER WILL CONTINUE THROUGH TONIGHT AS AN UPPER-LEVEL RIDGE HOLDS ACROSS THE REGION AND SURFACE HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC RIDGES INTO THE SOUTHEASTERN STATES. DEEPER MOISTURE WILL REMAIN JUST TO OUR WEST AND NORTH. LOWS TONIGHT WILL BE MAINLY IN THE MID 60S...EXCEPT SLIGHTLY WARMER ON THE AREA LAKES. WATER TEMPERATURES AT LAKE MURRAY IN THE LOW/MID 70S. && .SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... UPPER-LEVEL RIDGE AXIS OVER THE REGION WILL BEGIN BREAKING DOWN MONDAY AFTERNOON IN ADVANCE OF A FRONTAL BOUNDARY CROSSING THE TN VALLEY AND WESTERN GULF STATES. THIS WILL ALLOW ADDITIONAL MOISTURE INTO THE FORECAST AREA WITH PWAT VALUES MONDAY AFTERNOON AROUND 1.75 INCHES WITH MODERATE INSTABILITY. ALTHOUGH A STRONG TRIGGER WILL NOT BE IN PLACE CONVECTION WHICH DEVELOPS COULD TAP INTO SOME REMAINING MID-LEVEL DRY AIR RESULTING IN GUSTY OUTFLOWS AND GENESIS OF NEW CELLS. CONTINUE TO EXPECT CHANCE SHOWERS AND THUNDERSTORMS FOR MOST AREAS WITH LOW POTENTIAL FOR DAMAGING WINDS GUSTS. CONVECTION WILL DIMINISH WITH SUNSET WITH CLOUDS LINGERING MONDAY NIGHT AS THE BOUNDARY PUSHES INTO EASTERN TN AND THE CENTRAL GULF STATES BY DAYBREAK TUESDAY. MODELS HAVE DECREASED MOISTURE SLIGHTLY WITH THE LATEST RUN WITH PWAT VALUES AROUND 1.5 INCHES. FRONTAL BOUNDARY WILL CROSS THE AREA LATE TUESDAY AFTERNOON/TUESDAY EVENING AND...ALTHOUGH WEAK...WILL BE ENOUGH TO COMBINE WITH DIURNAL HEATING TO IGNITE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. SEVERE THREAT TUESDAY WILL REMAIN LOW. TEMPERATURES WILL BE IN THE UPPER 80S TO LOWER 90S FOR DAYTIME HIGHS WITH OVERNIGHT LOWS IN THE MID 60S TO NEAR 70. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM WITH WEAK HIGH PRESSURE NORTH OF THE AREA WEDNESDAY AND THE NEXT COLD FRONT CROSSING THE REGION THURSDAY. WITH LOW-LEVEL MOISTURE REMAINING IN PLACE AND THE FRONTAL BOUNDARY THROUGH THE REGION THE CHANCE OF MAINLY DIURNAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THURSDAY THROUGH SUNDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY ABOVE NORMAL. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... EXPECT MAINLY VFR CONDITIONS THROUGH THE TAF PERIOD. LOW-LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY HELP SUPPORT STRATUS AND FOG DURING THE EARLY MORNING HOURS. HOWEVER...MOISTURE APPEARS LIMITED AND THE NAM INDICATES SOME MIXING SHOULD OCCUR ASSOCIATED WITH A LOW-LEVEL JET. MOST OF THE GFS AND NAM MOS MAINTAIN VFR CONDITIONS. THE SREF GUIDANCE RESTRICTION PROBABILITIES ARE LOW. THE HRRR INDICATES CONTINUED VFR CONDITIONS. FORECASTED VFR CONDITIONS EXCEPT FOR A PERIOD OF MVFR FOG AT AGS AND OGB AROUND SUNRISE BASED ON THE ADDED MOISTURE AND COOLING ASSOCIATED WITH THE RIVER VALLEYS. HEATING AND MIXING SHOULD DISSIPATE ANY FOG LATER IN THE MORNING. HEATING...A PRE-FRONTAL TROUGH AND A MID- LEVEL SHORTWAVE TROUGH MOVING INTO THE RIDGE SHOULD HELP SUPPORT THUNDERSTORMS MONDAY AFTERNOON. EXPECT SCATTERED COVERAGE WITH THE THUNDERSTORM CHANCE TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN MAINLY AFTERNOON AND EVENING SCATTERED THUNDERSTORMS. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 99
AREA FORECAST DISCUSSION
NWS LINCOLN IL
900 PM CDT SUN MAY 17 2015 .UPDATE... ISSUED AT 852 PM CDT SUN MAY 17 2015 OVERNIGHT FORECAST DOING WELL. SOUTHERLY WINDS MAINTAINING SOME WARM TEMPS FOR THE OVERNIGHT...AND MAJORITY OF PRECIP THREAT ALONG AND SOUTH OF A LINE FROM TAYLORVILLE TO CHAMPAIGN. SHORT TERM MODELS PREV BLEW SOME CONVECTION INTO SOUTHEASTERN IL WORKING OFF OF OUTFLOW FROM ACTIVITY IN MO. HOWEVER, ATMOSPHERE HAVING DIFFICULT TIME FOCUSING ANY LIFT, PARTICULARLY WITH THE LOSS OF THE DIURNAL COMPONENT TO THE INSTABILITY. SHOWERS SO FAR HAVE REMAINED LIMITED AND THE BULK OF THE THUNDER FURTHER TO THE SOUTH. ISO TS POSSIBLE IN THE FAR SE...BUT NOT WIDESPREAD. NOT MUCH IN THE WAY OF UPDATES ANTICIPATED AT THIS TIME. && .SHORT TERM...(TONIGHT) ISSUED AT 256 PM CDT SUN MAY 17 2015 POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF 2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT. HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 256 PM CDT SUN MAY 17 2015 COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY. WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE OVERNIGHT LOWS DIP INTO THE 40S. PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER. ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY AND FRIDAY. MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 636 PM CDT SUN MAY 17 2015 MODELS INCONSISTENT AND NOT DOING WELL WITH TIMING OR DEVELOPMENT OF CONVECTION AND CONSIDERING THE LACK OF ACTIVITY OUT TO THE WEST THIS AFTERNOON...KEEPING EVEN MENTION OUT. MAY NEED TO CONSIDER ADDING VCTS TO DEC OR CMI IN THE OVERNIGHT DEPENDING ON TRACK OF WEAK CONVECTION TO THE SOUTHWEST...BUT SO FAR...NOT A MAJOR THREAT. GUSTS EXPECTED TO SLACK OFF AS SUN SETS...WINDS BECOMING MORE WESTERLY BY TOMORROW AND SOME SCT CU ALONG AND SOUTHEAST OR A BMI TO SPI LINE FOR THE MOST PART, WITH SOME CIRRUS. SO FAR, A VFR FORECAST THROUGH 24 HRS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...BARNES LONG TERM...BARNES AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
639 PM CDT SUN MAY 17 2015 .SHORT TERM...(TONIGHT) ISSUED AT 256 PM CDT SUN MAY 17 2015 POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF 2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT. HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 256 PM CDT SUN MAY 17 2015 COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY. WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE OVERNIGHT LOWS DIP INTO THE 40S. PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER. ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY AND FRIDAY. MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 636 PM CDT SUN MAY 17 2015 MODELS INCONSISTENT AND NOT DOING WELL WITH TIMING OR DEVELOPMENT OF CONVECTION AND CONSIDERING THE LACK OF ACTIVITY OUT TO THE WEST THIS AFTERNOON...KEEPING EVEN MENTION OUT. MAY NEED TO CONSIDER ADDING VCTS TO DEC OR CMI IN THE OVERNIGHT DEPENDING ON TRACK OF WEAK CONVECTION TO THE SOUTHWEST...BUT SO FAR...NOT A MAJOR THREAT. GUSTS EXPECTED TO SLACK OFF AS SUN SETS...WINDS BECOMING MORE WESTERLY BY TOMORROW AND SOME SCT CU ALONG AND SOUTHEAST OR A BMI TO SPI LINE FOR THE MOST PART, WITH SOME CIRRUS. SO FAR, A VFR FORECAST THROUGH 24 HRS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1234 PM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 947 AM CDT SAT MAY 16 2015 SHOWERS INCREASING IN COVERAGE TO OUR SOUTH...AND HAVE SEEN SCATTERED SHOWERS ALSO DEVELOPING MORE WITHIN OUR FORECAST AREA. SO FAR THUNDER UPSTREAM HAS BEEN RATHER MINIMAL...AND SURFACE BASED CAPE VALUES PROGGED BY THE RAP MODEL EXPECTED TO BE LESS THAN 500 J/KG FROM ABOUT I-57 EASTWARD. WITH NO SUBSTANTIAL HEATING IN THAT AREA...HAVE DOWNPLAYED THE THUNDER POTENTIAL ACROSS THE EASTERN CWA THROUGH THE AFTERNOON. FURTHER WEST... CAPES 1000-1500 J/KG EXPECTED AND THERE ARE ALSO SOME SUBSTANTIAL BREAKS IN THE CLOUDS ACROSS SOUTHERN IOWA AND NORTHEAST MISSOURI...SO HAVE MAINTAINED GENERAL SHOWER/THUNDERSTORM MENTION ACROSS THE REMAINDER OF THE FORECAST AREA. WITH RAIN ACROSS THE SOUTHEAST CWA EXPECTED TO BECOME FAIRLY WIDESPREAD...HAVE LOWERED HIGHS IN THAT AREA A COUPLE DEGREES...WITH MOST OF THE REMAINING CWA GENERALLY EXPECTED TO REACH AROUND 80 DEGREES. && .SHORT TERM...(TODAY) ISSUED AT 336 AM CDT SAT MAY 16 2015 ANOTHER RELATIVELY WARM AND HUMID DAY IS ANTICIPATED ACROSS CENTRAL AND SOUTHEAST ILLINOIS TODAY AS SOUTHERLY LOW LEVEL FLOW PERSISTS. DAYTIME HIGHS MAY BE A FEW DEGREES COOLER THAN YESTERDAY, ESPECIALLY ACROSS SOUTHEAST ILLINOIS WHERE CLOUD COVER WILL BE THICKEST AND RAINFALL MOST WIDESPREAD, BUT MOST LOCATIONS SHOULD STILL CRACK THE 80 DEGREE MARK. AS FAR AS SHOWER/STORM POTENTIAL TODAY, GIVEN THE FAIRLY JUICED UP LOW-LEVEL AIRMASS AND LACK OF APPRECIABLE CAPPING, IT WILL NOT TAKE MUCH TO POP OFF SOME CONVECTION. PLAN TO CARRY AT LEAST CHANCE POPS AREAWIDE TODAY GIVEN THIS POTENTIAL. MODEL PROGS SUGGEST MOST OF THE FORECAST AREA SHOULD SEE DIURNALLY INDUCED CAPE VALUES OF AT 1500 J/KG, ALTHOUGH SHEAR PROFILES SHOULD BE QUITE WEAK OVER THE NORTHERN 2/3 OR SO OF THE REGION. THE BETTER FORCING ACROSS SOUTHEAST ILLINOIS WILL COME COURTESY OF A WEAK SHORT WAVE LIFTING NORTHEAST FROM THE MID-MISSISSIPPI RIVER VALLEY. HAVE BUMPED POPS UP TO CATEGORICAL SOUTH OF I-70 FOR THE MIDDAY/EARLY AFTERNOON HOURS TO ACCOUNT FOR THE PASSAGE OF THIS WAVE. .LONG TERM...(TONIGHT THROUGH FRIDAY) ISSUED AT 336 AM CDT SAT MAY 16 2015 DIURNALLY ENHNANCED CONVECTION THIS AFTERNOON AND EARLY EVENING WILL DIMINISH IN COVERAGE AFTER SUNSET SIMILAR TO WHAT HAPPENED FRIDAY EVENING AS INSTABILITY WANES. WILL CARRY HIGHEST POPS IN SOUTHEAST IL THIS EVENING ESPECIALLY BEFORE DARK WITH SHORT WAVES NEAR EASTERN/SE IL EARLY THIS EVENING AROUND 00Z/7 PM. MILD LOWS TONIGHT IN THE MID TO UPPER 60S WITH MILDEST READINGS SW AREAS. CUTOFF LOW OVER THE CENTRAL ROCKIES TO EJECT NE INTO MN BY SUNDAY EVENING AND HAS A PREFRONTAL TROF PUSHING EAST TOWARD THE MS RIVER. THIS TO INCREASE CHANCES OF CONVECTION FROM WEST TO EAST DURING THE DAY SUNDAY AND THEN DIMINISH FROM WEST TO EAST DURING SUNDAY NIGHT. SPC HAS SLIGHT RISK OF SEVERE STORMS SUNDAY AFTERNOON/EVENING FROM BLOOMINGTON TO TAYLORVILLE WEST WHERE STRONGER BULK SHEAR OF 35-45 KTS OCCURS ALONG WITH INCREASE INSTABILITY WITH CAPES PEAKING AROUND 2500 J/KG SUNDAY AFTERNOON. WARM HIGHS IN THE LOWER 80S SUNDAY WITH BREEZY SSW WINDS AND MUGGY DEWPOINTS IN THE MID TO UPPER 60S. MAIN COLD FRONT TO PUSH EAST ACROSS IL DURING MONDAY AND BRINGS BEST CHANCES OF SHOWERS AND THUNDERSTORMS TO AREAS EAST OF I-55. SPC KEEPS MARGINAL RISK OF SEVERE EAST OF IL OVER PARTS OF INDIANA ON MONDAY. HAVE BUMPED UP THE HIGHS ON MONDAY A FEW DEGREES WITH MID 70S FROM IL RIVER NW TO LOWER 80S IN EASTERN IL. DRIER...COOLER AND LESS HUMID AIR USHERS INTO IL DURING MONDAY NIGHT AND TUE BEHIND THE COLD FRONT. LOWS MONDAY NIGHT RANGE FROM MID 40S NW OF IL RIVER TO NEAR 55F FAR SE IL NEAR WABASH RIVER BY LAWRENCVILLE. HIGHS TUE IN THE MID 60S CENTRAL IL AND 65-70F IN SOUTHEAST IL. A COOL NIGHT AHEAD FOR TUE NIGHT WITH LOWS IN THE MID TO UPPER 40S. EXTENDED MODELS TRY TO BRING SOME QPF BACK INTO PARTS OF CENTRAL AND ESPECIALLY SOUTHERN/SW IL WED AND THEN SUPPRESS IS SOUTHWARD BY THU WITH SOME ENERGY EJECTING FROM THE UPPER LEVEL TROF/LOW NEAR CA AND MOVING INTO THE MID/LOWER MS RIVER VALLEY. WILL KEEP POPS LOW FROM WED-THU WITH MAINLY SLIGHT CHANCES, THOUGH SW AREAS HAVE CHANCE POPS 30-40% WED AND WED EVENING. HIGHS IN THE LOW TO MID 60S WED AND 65 TO 70F ON THU. TEMPS CONTINUE TO SLOWLY MODIFY FRIDAY WITH HIGHS MAINLY IN THE LOWER 70S AND DRY CONDITIONS WITH WEAK HIGH PRESSURE IN THE CENTRAL PLAINS AND RIDGING EAST TOWARD IL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1234 PM CDT SAT MAY 16 2015 SOME MVFR CEILINGS LINGER AROUND KBMI/KCMI AT MIDDAY...BUT THESE SHOULD CONTINUE TO IMPROVE. ASIDE FROM A CLUSTER OF STORMS THAT HAVE RECENTLY PASSED KBMI...CONVECTION REMAINS RATHER ISOLATED AND DISORGANIZED. THE CURRENT STATE OF THE ATMOSPHERE DOES NOT HAVE ANY PARTICULAR BOUNDARIES OR FRONTS TO FOCUS THE ACTION...THUS WILL MAINTAIN THE VCTS MENTIONS FOR NOW...AND WILL UPDATE WHEN THE CONVECTION STARTS TO GET ORGANIZED. MOST OF THE HIGH- RESOLUTION MODEL GUIDANCE LARGELY HAS THE THREAT OUT OF CENTRAL ILLINOIS BY 00Z AND HAVE KEPT THE OVERNIGHT HOURS DRY. SOME QUESTION AS TO HOW LOW THE CEILINGS WILL GET AND WILL GO WITH LOW-END MVFR CEILINGS AT ALL SITES. LOW-LEVEL WIND SHEAR IS MARGINAL FOR TONIGHT...BUT WILL HAVE TO MONITOR THIS POTENTIAL OVER THE NEXT FEW HOURS. SOME OF THIS LOW LEVEL JET WILL WORK TOWARD THE SURFACE SUNDAY MORNING...AND SOUTHERLY GUSTS SHOULD START REACHING 20 KNOTS OR SO BY MID MORNING. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...BAK LONG TERM...07 AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
948 AM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 947 AM CDT SAT MAY 16 2015 SHOWERS INCREASING IN COVERAGE TO OUR SOUTH...AND HAVE SEEN SCATTERED SHOWERS ALSO DEVELOPING MORE WITHIN OUR FORECAST AREA. SO FAR THUNDER UPSTREAM HAS BEEN RATHER MINIMAL...AND SURFACE BASED CAPE VALUES PROGGED BY THE RAP MODEL EXPECTED TO BE LESS THAN 500 J/KG FROM ABOUT I-57 EASTWARD. WITH NO SUBSTANTIAL HEATING IN THAT AREA...HAVE DOWNPLAYED THE THUNDER POTENTIAL ACROSS THE EASTERN CWA THROUGH THE AFTERNOON. FURTHER WEST... CAPES 1000-1500 J/KG EXPECTED AND THERE ARE ALSO SOME SUBSTANTIAL BREAKS IN THE CLOUDS ACROSS SOUTHERN IOWA AND NORTHEAST MISSOURI...SO HAVE MAINTAINED GENERAL SHOWER/THUNDERSTORM MENTION ACROSS THE REMAINDER OF THE FORECAST AREA. WITH RAIN ACROSS THE SOUTHEAST CWA EXPECTED TO BECOME FAIRLY WIDESPREAD...HAVE LOWERED HIGHS IN THAT AREA A COUPLE DEGREES...WITH MOST OF THE REMAINING CWA GENERALLY EXPECTED TO REACH AROUND 80 DEGREES. && .SHORT TERM...(TODAY) ISSUED AT 336 AM CDT SAT MAY 16 2015 ANOTHER RELATIVELY WARM AND HUMID DAY IS ANTICIPATED ACROSS CENTRAL AND SOUTHEAST ILLINOIS TODAY AS SOUTHERLY LOW LEVEL FLOW PERSISTS. DAYTIME HIGHS MAY BE A FEW DEGREES COOLER THAN YESTERDAY, ESPECIALLY ACROSS SOUTHEAST ILLINOIS WHERE CLOUD COVER WILL BE THICKEST AND RAINFALL MOST WIDESPREAD, BUT MOST LOCATIONS SHOULD STILL CRACK THE 80 DEGREE MARK. AS FAR AS SHOWER/STORM POTENTIAL TODAY, GIVEN THE FAIRLY JUICED UP LOW-LEVEL AIRMASS AND LACK OF APPRECIABLE CAPPING, IT WILL NOT TAKE MUCH TO POP OFF SOME CONVECTION. PLAN TO CARRY AT LEAST CHANCE POPS AREAWIDE TODAY GIVEN THIS POTENTIAL. MODEL PROGS SUGGEST MOST OF THE FORECAST AREA SHOULD SEE DIURNALLY INDUCED CAPE VALUES OF AT 1500 J/KG, ALTHOUGH SHEAR PROFILES SHOULD BE QUITE WEAK OVER THE NORTHERN 2/3 OR SO OF THE REGION. THE BETTER FORCING ACROSS SOUTHEAST ILLINOIS WILL COME COURTESY OF A WEAK SHORT WAVE LIFTING NORTHEAST FROM THE MID-MISSISSIPPI RIVER VALLEY. HAVE BUMPED POPS UP TO CATEGORICAL SOUTH OF I-70 FOR THE MIDDAY/EARLY AFTERNOON HOURS TO ACCOUNT FOR THE PASSAGE OF THIS WAVE. .LONG TERM...(TONIGHT THROUGH FRIDAY) ISSUED AT 336 AM CDT SAT MAY 16 2015 DIURNALLY ENHNANCED CONVECTION THIS AFTERNOON AND EARLY EVENING WILL DIMINISH IN COVERAGE AFTER SUNSET SIMILAR TO WHAT HAPPENED FRIDAY EVENING AS INSTABILITY WANES. WILL CARRY HIGHEST POPS IN SOUTHEAST IL THIS EVENING ESPECIALLY BEFORE DARK WITH SHORT WAVES NEAR EASTERN/SE IL EARLY THIS EVENING AROUND 00Z/7 PM. MILD LOWS TONIGHT IN THE MID TO UPPER 60S WITH MILDEST READINGS SW AREAS. CUTOFF LOW OVER THE CENTRAL ROCKIES TO EJECT NE INTO MN BY SUNDAY EVENING AND HAS A PREFRONTAL TROF PUSHING EAST TOWARD THE MS RIVER. THIS TO INCREASE CHANCES OF CONVECTION FROM WEST TO EAST DURING THE DAY SUNDAY AND THEN DIMINISH FROM WEST TO EAST DURING SUNDAY NIGHT. SPC HAS SLIGHT RISK OF SEVERE STORMS SUNDAY AFTERNOON/EVENING FROM BLOOMINGTON TO TAYLORVILLE WEST WHERE STRONGER BULK SHEAR OF 35-45 KTS OCCURS ALONG WITH INCREASE INSTABILITY WITH CAPES PEAKING AROUND 2500 J/KG SUNDAY AFTERNOON. WARM HIGHS IN THE LOWER 80S SUNDAY WITH BREEZY SSW WINDS AND MUGGY DEWPOINTS IN THE MID TO UPPER 60S. MAIN COLD FRONT TO PUSH EAST ACROSS IL DURING MONDAY AND BRINGS BEST CHANCES OF SHOWERS AND THUNDERSTORMS TO AREAS EAST OF I-55. SPC KEEPS MARGINAL RISK OF SEVERE EAST OF IL OVER PARTS OF INDIANA ON MONDAY. HAVE BUMPED UP THE HIGHS ON MONDAY A FEW DEGREES WITH MID 70S FROM IL RIVER NW TO LOWER 80S IN EASTERN IL. DRIER...COOLER AND LESS HUMID AIR USHERS INTO IL DURING MONDAY NIGHT AND TUE BEHIND THE COLD FRONT. LOWS MONDAY NIGHT RANGE FROM MID 40S NW OF IL RIVER TO NEAR 55F FAR SE IL NEAR WABASH RIVER BY LAWRENCVILLE. HIGHS TUE IN THE MID 60S CENTRAL IL AND 65-70F IN SOUTHEAST IL. A COOL NIGHT AHEAD FOR TUE NIGHT WITH LOWS IN THE MID TO UPPER 40S. EXTENDED MODELS TRY TO BRING SOME QPF BACK INTO PARTS OF CENTRAL AND ESPECIALLY SOUTHERN/SW IL WED AND THEN SUPPRESS IS SOUTHWARD BY THU WITH SOME ENERGY EJECTING FROM THE UPPER LEVEL TROF/LOW NEAR CA AND MOVING INTO THE MID/LOWER MS RIVER VALLEY. WILL KEEP POPS LOW FROM WED-THU WITH MAINLY SLIGHT CHANCES, THOUGH SW AREAS HAVE CHANCE POPS 30-40% WED AND WED EVENING. HIGHS IN THE LOW TO MID 60S WED AND 65 TO 70F ON THU. TEMPS CONTINUE TO SLOWLY MODIFY FRIDAY WITH HIGHS MAINLY IN THE LOWER 70S AND DRY CONDITIONS WITH WEAK HIGH PRESSURE IN THE CENTRAL PLAINS AND RIDGING EAST TOWARD IL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 639 AM CDT SAT MAY 16 2015 AREAS OF IFR STRATUS AND FOG HAVE DEVELOPED ACROSS CENTRAL ILLINOIS EARLY THIS MORNING. THIS STRATUS/FOG SHOULD BURN OFF WITHIN THE NEXT FEW HOURS AS DIURNAL HEATING INCREASES. THEN, ATTENTION TURNS TO AN UPPER LEVEL DISTURBANCE LIFTING NORTHEAST INTO THE AREA. THIS DISTURBANCE SHOULD PRODUCE AT LEAST SCATTERED SHOWERS/STORMS TODAY AS IT MOVES THROUGH, WITH KDEC & KCMI THE MOST LIKELY OF THE LOCAL TERMINALS TO BE IMPACTED. HAVE INCLUDED A 4 HOUR TEMPO FOR THUNDER AT THOSE LOCATIONS DURING THE PREFERRED TIME PERIOD, BUT ONLY INCLUDED A VCTS AT KPIA, KBMI, AND KSPI AS THE STORM COVERAGE SHOULD BE MORE SPOTTY FURTHER WEST. CAN`T RULE OUT SOME CONVECTION POPPING UP OUTSIDE THE FAVORED DIURNAL HEATING PERIOD, WHICH OVERLAPS TODAY WITH THE PASSAGE OF THE DISTURBANCE, BUT EXPECTED COVERAGE IS TOO LOW TO MENTION AT THIS TIME. AS THE AIRMASS, CLOUD, AND WIND CONDITIONS SHOULD BE SIMILAR TONIGHT TO EARLY THIS MORNING, PLAN TO HAVE IFR CONDITIONS DEVELOPING ONCE AGAIN LATER TONIGHT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...BAK LONG TERM...07 AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1152 PM CDT FRI MAY 15 2015 .UPDATE... ISSUED AT 906 PM CDT FRI MAY 15 2015 PLENTY OF WARM AIR ADVECTING INTO THE REGION AND WIDESPREAD MID/HIGH LEVEL CLOUDS IN ADDITION TO REMAINING LOW WILL KEEP THE TEMPS UP OVERNIGHT FOR CENTRAL ILLINOIS. ALTHOUGH LLVL RH HAS BEEN ENHANCED BY THE EVENINGS RAINFALL...WIDESPREAD FOG NOT LIKELY AS THE WINDS AND TEMPS STAY UP OVERNIGHT. WILL HAVE TO WATCH FOR SOME PATCHY VIS REDUCTIONS, BUT NOT ENOUGH CONFIDENCE TO PUT IT IN THE ZONES JUST YET. UPDATES FOR THE BREAK IN THE PRECIP...BRINGING BACK CHANCE POPS IN THE VERY EARLY HOURS OF THE MORNING AS MODELS STILL SPLIT OVER HOW TO HANDLE A POTENTIAL ROUND TWO. && .SHORT TERM...(TONIGHT) ISSUED AT 253 PM CDT FRI MAY 15 2015 THUNDERSTORMS HAVE BEEN ON THE INCREASE ACROSS MISSOURI THE LAST FEW HOURS AS A SHORTWAVE LIFTS NORTHEAST...WITH MORE ISOLATED CONVECTION IN THE SOUTHEASTERN CWA. NOT MUCH HOLDING THESE STORMS BACK AS SURFACE BASED CAPE`S ARE OVER 2500 J/KG...BUT VERY LITTLE WIND SHEAR ALOFT IS RESULTING IN A MORE PULSE-TYPE STORM ENVIRONMENT. HRRR MODEL LIFTS THE BULK OF THESE STORMS THROUGH THE FORECAST AREA BY 8- 9 PM. MODEL GUIDANCE BEYOND THAT GETS A BIT MORE DISJOINTED...AS SEVERAL OF THE HIGH-RESOLUTION MODELS PRETTY MUCH DRY THINGS OUT ALTHOUGH THE HRRR TRIES TO BRING ANOTHER LOBE THROUGH LATE EVENING. HAVE LARGELY GONE WITH 30-40% POP`S THROUGH THE NIGHT IN MOST AREAS EXCEPT FOR SOME HIGHER VALUES EARLY EVENING ACROSS THE SOUTHWEST CWA WITH THE CURRENT ACTIVITY. HOURLY TEMPERATURES WILL BE TRICKY AS THE STORMS WILL CAUSE SOME TEMPORARY COOLDOWNS...BUT OVERALL LOWS IN THE MID 60S REQUIRED LITTLE CHANGE FROM THE PREVIOUS FORECAST. .LONG TERM...(SATURDAY THROUGH FRIDAY) ISSUED AT 253 PM CDT FRI MAY 15 2015 MORNING UPPER AIR AND MOISTURE CHANNEL IMAGERY SHOWS CLOSED UPPER LOW IN ROCKIES WITH A MAIN VORT LOBE IN THE CENTRAL PLAINS, ADVECTING DEEP MOISTURE PLUME NORTHWARD FROM TX INTO THE CENTRAL MIDWEST. SURFACE DATA SHOWS VERY MOIST AIRMASS OVER IL REGION, WITH 2500 CAPE, DEW POINTS APPROACHING 70 AND TEMPS IN LOWER 80S. WITH THE PROGGED CONTINUING OF THE MOISTURE FETCH NORTHWARD TONIGHT THROUGH MUCH OF STATE SATURDAY, THERE WILL BE LITTLE CHANGE IN RESULT FOR THE START OF WEEKEND. EXPECT SCATTERED STORMS TONIGHT INTO DAY SATURDAY, BUT WILL LIMITED SHEAR AVAILABLE, SEVERE POTENTIAL WILL BE ON THE LOCALIZED SCALE. BY SUNDAY THOUGH, PATTERN CHANGES AS THE UPPER LOW STARTS TO MOVE NORTHEAST SATURDAY NIGHT. BY SUNDAY IT REACHES THE DAKOTAS AND ANOTHER WAVE ROTATES EAST AROUND THE LOW INTO THE PLAINS. THIS WILL GET THE FRONT MOVING EAST, PROVIDING AN INCREASE IN SHEAR AND CONVERGENCE INTO THE IL REGION ON SUNDAY. WITH LITTLE CHANGE IN MOISTURE, THE AFTERNOON AND EVENING WILL BE THE BEST CHANCES FOR ORGANIZED SEVERE. AMOUNT OF SHEAR AND STRENGTH OF UPPER LEVEL SUPPORT IN THE AREA STILL A LITTLE UNCERTAIN, BUT A SLIGHT RISK OF SEVERE STILL IS SUPPORTABLE. DRYING SUNDAY NIGHT AS UPPER WAVE MOVES EAST WILL CLEAR PCPN CHANCES FOR MONDAY. COOLER AIR MOVES IN AND WILL SOME WEAK RIDGING ALOFT, QUITE WEATHER IS RULE EARLY IN THE WEEK. A WEAK UPPER LEVEL WAVE MOVES OUT OF STILL STAGNATE UPPER TROUGH IN THE WESTERN ROCKIES, WHICH WILL BRING CHANCE OF PCPN WED TO THURS, BUT WITH DRIER, MORE STABLE AIR IN AREA, SLIGHT CHANCE POPS ARE THE RESULT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1149 PM CDT FRI MAY 15 2015 ILX TERMINALS STILL ANCHORED IN THE WARM SECTOR OF SORTS TOMORROW...MAINTAINING THE TREND OF SOUTHERLY WINDS AND SHOWERS AND THUNDERSTORMS WITH A DIURNAL COMPONENT THROUGH TOMORROW. MODELS INCONSISTENT WITH TIMING OF THE ONSET OF SHOWERS...BUT WITH THE RUNS THAT HAVE IT EARLIER...THEY ARE ALSO OVERDONE WITH THE SECONDARY SHOWERS TO THE SOUTHWEST. AS A RESULT...KEEPING TO VCSH UNTIL ROUGHLY MIDDAY. SPREAD OF PRECIP NOT A PROGRESSION BUT MORE SCATTERED. PULLING BACK ON THE RAIN MENTION FOR THE EVENING WITH THE MID DECK REESTABLISHING...VERY SIMILAR TO THIS EVENING. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...GEELHART LONG TERM...GOETSCH AVIATION...HJS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
219 PM EDT SAT MAY 16 2015 .SYNOPSIS... ISSUED AT 149 PM EDT SAT MAY 16 2015 THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 75...WITH LOW TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 402 AM EDT SAT MAY 16 2015 NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500 K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY WIND DOWN IN THE 12-14Z TIMEFRAME. LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO WARM. FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID 60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 402 AM EDT SAT MAY 16 2015 PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z. AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET. STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5 C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000 J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR. ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST. SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 215 PM EDT SAT MAY 16 2015 LOTS OF WEAK ENERGY DISTURBANCES AND AREAS OF DIFFERENTIAL HEATING ALLOWING DISORGANIZED BANDS OF SHOWERS AND A FEW STORMS TO DEVELOP AND PERSIST OVER THE AREA. ALSO...MFR CLOUDS HANGING AROUND UNDER A DEEP COLUMN OF MOISTURE WHICH WAS SATURATED OR NEARLY SATURATED UP TO 400 MB AS INDICATED ON SOME ACARS/AFCT SOUNDINGS. REALLY HARD TO PICK A TIME FOR SHOWERS OR A STORMS AT EITHER TAF SITE. WENT FAIRLY CONSERVATIVE ON PLACING ANY SHOWERS OR STORMS AT TAF SITES AS OVERALL SHOWER/STORM COVERAGE SHOULD NOT BE THAT GREAT. HOWEVER... MADE TAFS MUCH MORE PESSIMISTIC WITH ANY CLEARING OF MVFR CLOUDS. HAVE BROUGHT BOTH SBN AND FWA SITES DOWN TO LOW MVFR... WITH THE POSSIBILITY INCREASING FOR IFR CONDITIONS AT SOME POINT TONIGHT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MCD/SKIPPER SHORT TERM...MARSILI LONG TERM...AGD AVIATION...SKIPPER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1022 AM EDT SAT MAY 16 2015 .SYNOPSIS... ISSUED AT 1021 AM EDT SAT MAY 16 2015 THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 80...WITH LOW TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 402 AM EDT SAT MAY 16 2015 NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500 K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY WIND DOWN IN THE 12-14Z TIMEFRAME. LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO WARM. FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID 60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 402 AM EDT SAT MAY 16 2015 PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z. AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET. STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5 C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000 J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR. ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST. SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 544 AM EDT SAT MAY 16 2015 THE COMBINATION OF LOW/MID LEVEL MOISTURE TRANSPORT AND SEVERAL WEAK EMBEDDED WAVES IN SOUTHWEST FLOW HAS LED TO NARROW BAND OF SHOWERS FROM KSBN TO NORTH OF KFWA EARLY THIS MORNING. THIS BAND WILL LIFT NORTH OF KSBN BY 12Z. A LULL IS THEN EXPECTED IN TERMS OF PRECIP COVERAGE FOR THE TERMINALS...ALTHOUGH ADDITIONAL IMPULSES EJECTING OUT OF SOUTHERN MISSOURI/ARKANSAS WILL POSE A THREAT FOR ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS FROM LATE MORNING INTO THIS AFTERNOON. CURRENT INDICATIONS WOULD SUGGEST A MORE FAVORABLE SHORT WAVE TRACK FOR NORTHEAST INDIANA. THUS...GREATER CONVECTIVE COVERAGE MAY AFFECT KFWA LATER THIS MORNING INTO THIS AFTERNOON. HOWEVER WITH LOW CONFIDENCE IN TIMING AND POINT PROBABILITIES...WILL LIMIT MENTION TO VCSH AT KFWA AT THIS TIME. LIGHT SOUTH WINDS THIS MORNING WILL BECOME SOUTHWEST 10 TO 15 KNOTS WITH DIURNAL MIXING THIS MORNING...AND THEN LIGHT SOUTH AGAIN TONIGHT. DID ADD SOME MVFR VSBYS AT KSBN LATER TONIGHT IN CLOSER PROXIMITY TO OLD LOW LEVEL BOUNDARY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MCD SHORT TERM...MARSILI LONG TERM...AGD AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
611 AM EDT SAT MAY 16 2015 .SYNOPSIS... ISSUED AT 136 AM EDT SAT MAY 16 2015 THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT IN A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 80...WITH LOW TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 402 AM EDT SAT MAY 16 2015 NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500 K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY WIND DOWN IN THE 12-14Z TIMEFRAME. LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO WARM. FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID 60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 402 AM EDT SAT MAY 16 2015 PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z. AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET. STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5 C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000 J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR. ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST. SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 544 AM EDT SAT MAY 16 2015 THE COMBINATION OF LOW/MID LEVEL MOISTURE TRANSPORT AND SEVERAL WEAK EMBEDDED WAVES IN SOUTHWEST FLOW HAS LED TO NARROW BAND OF SHOWERS FROM KSBN TO NORTH OF KFWA EARLY THIS MORNING. THIS BAND WILL LIFT NORTH OF KSBN BY 12Z. A LULL IS THEN EXPECTED IN TERMS OF PRECIP COVERAGE FOR THE TERMINALS...ALTHOUGH ADDITIONAL IMPULSES EJECTING OUT OF SOUTHERN MISSOURI/ARKANSAS WILL POSE A THREAT FOR ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS FROM LATE MORNING INTO THIS AFTERNOON. CURRENT INDICATIONS WOULD SUGGEST A MORE FAVORABLE SHORT WAVE TRACK FOR NORTHEAST INDIANA. THUS...GREATER CONVECTIVE COVERAGE MAY AFFECT KFWA LATER THIS MORNING INTO THIS AFTERNOON. HOWEVER WITH LOW CONFIDENCE IN TIMING AND POINT PROBABILITIES...WILL LIMIT MENTION TO VCSH AT KFWA AT THIS TIME. LIGHT SOUTH WINDS THIS MORNING WILL BECOME SOUTHWEST 10 TO 15 KNOTS WITH DIURNAL MIXING THIS MORNING...AND THEN LIGHT SOUTH AGAIN TONIGHT. DID ADD SOME MVFR VSBYS AT KSBN LATER TONIGHT IN CLOSER PROXIMITY TO OLD LOW LEVEL BOUNDARY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...AGD AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
404 AM EDT SAT MAY 16 2015 .SYNOPSIS... ISSUED AT 136 AM EDT SAT MAY 16 2015 THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT IN A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 80...WITH LOW TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 402 AM EDT SAT MAY 16 2015 NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500 K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY WIND DOWN IN THE 12-14Z TIMEFRAME. LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY PICK THESE UPSTREAM WAVES OUT THIS MORNING...ALTHOUGH BULK OF GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE FAVORABLE SHORT WAVE TRACK THIS AFTERNOON. A MODEST MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO WARM. FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID 60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 402 AM EDT SAT MAY 16 2015 PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z. AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET. STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5 C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000 J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR. ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST. SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 136 AM EDT SAT MAY 16 2015 UPPER LEVEL RIDGING WILL REBUILD ACROSS THE GREAT LAKES REGION TODAY...ALTHOUGH SEVERAL SMALL SCALE DISTURBANCES IN SOUTHWEST FLOW ALOFT COMBINED WITH WEAK TO MODERATE AFTERNOON INSTABILITY MAY RESULT IN ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS. GIVEN WEAK NATURE TO FORCING MECHANISMS AND INSTABILITY POSSIBLY A BIT MORE TEMPERED IN COMPARISON TO YESTERDAY...HAVE OPTED TO CONTINUE TO REFRAIN FROM ANY MENTION WITH THE 06Z TAFS DUE TO LOW CONFIDENCE. THUNDER CHANCES TONIGHT APPEAR TO BE QUITE LOW GIVEN WEAKENING INSTABILITY AND BETTER FORCING HOLDING OFF UNTIL AFTER THIS FORECAST VALID PERIOD. SOME PATCHY FOG MAY FORM OVER THE NEXT SEVERAL HOURS AND HAVE MAINTAINED TREND TO MVFR CONDITIONS IN THE 09Z-13Z TIMEFRAME. OTHERWISE...LIGHT SOUTH WINDS OVERNIGHT WILL BECOME SOUTHWESTERLY AFTER 14Z WITH SOME GUSTS TO 15 TO 20 KNOTS NOT OUT OF THE QUESTION. SOME MORE PATCHY FOG IS POSSIBLE AGAIN FOR SATURDAY NIGHT...AND WILL ADDRESS THIS MORE FULLY WITH THE 12Z TAFS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...AGD AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1127 PM CDT FRI MAY 15 2015 .SHORT TERM /TONIGHT/... ISSUED AT 425 PM CDT FRI MAY 15 2015 LOW PRESSURE CONTINUES TO WORK ITS WAY OFF OF THE ROCKIES AND INTO NE COLORADO AND SW NEBRASKA THIS AFTERNOON AND WILL BE THE MAIN DRIVER OF WEATHER OVER THE WEEKEND...BUT NOT IN THIS PERIOD. INSTEAD...VORTICITY ASSOCIATED WITH A SHORTWAVE MOVING UP THROUGH THE PLAINS HAS KICKED OFF CONVECTION IN E KANSAS AND W AND C MISSOURI. THETA-E ADVECTION IS NOT SIGNIFICANT WITH THE CONVECTION IN KANSAS...BUT IS MORE SO IN MISSOURI AND IS EXPECTED TO INCREASE LATER THIS AFTERNOON AND EVENING AS THE LOW LEVEL FLOW INCREASES AND HELPS KEEP SHOWERS AND STORMS GOING AS DAYTIME HEATING AND INSTABILITY BEGINS TO WANE. A FEW STORMS MAY CONTAIN SEVERE HAIL AND HIGH WINDS EARLY THIS EVENING WITH CAPE VALUES IN EXCESS OF 1500- 2000 J/KG...WIDESPREAD SEVERE IS NOT EXPECTED THOUGH GIVEN THE LACK OF SUPPORTIVE SHEAR. SHOWERS AND STORMS ARE ALREADY IN THE SW CWA AND WILL CONTINUE TO MOVE NORTHEAST...REACHING THE DES MOINES METRO AROUND 00Z...AND THE WATERLOO AROUND 03Z...WEAKENING AS THE EVENING GOES ON. THE HIGH-RES MODELS HAVE NOT BEEN IN GREAT AGREEMENT...WITH THE HRRR OVERLY AGGRESSIVE IN PROGRESSION. THE ARW-EAST HAS THE BEST HANDLE ON CONVECTION CURRENTLY...AND HAVE LEANED THAT WAY FOR POPS THIS EVENING. AM EXPECTING LOCALLY DENSE FOG OVERNIGHT...AS WELL...WITH HIGH DEW PTS FROM INCOMING PRECIP AND SOLID MOISTURE TRANSPORT THROUGH THE EVENING AND OVERNIGHT...BUT WILL REFRAIN FROM WIDESPREAD FOR NOT AND DENOTE PATCHY FOG. .LONG TERM /SATURDAY THROUGH FRIDAY/... ISSUED AT 425 PM CDT FRI MAY 15 2015 DYNAMIC UPPER LEVEL SYSTEM EXTENDING FROM SOUTHERN CALIFORNIA THROUGH IDAHO WILL SEGMENT INTO TWO SECTIONS WITH ONE SEGMENT LIFTING INTO WYOMING AND MONTANA AND LINGERING THERE THROUGH SUNDAY. THE STRONGER SEGMENT WILL MOVE EAST THROUGH THE DESERT SOUTHWEST ON SUNDAY THEN LIFT NORTHEAST THROUGH THE TEXAS PANHANDLE LATE SATURDAY THEN OVER EASTERN NEBRASKA BY EARLY SUNDAY. THE INITIAL SHORTWAVE THAT WILL MOVE ACROSS IOWA OVERNIGHT WILL LEAVE SOME STABILITY THROUGH THE MORNING WITH THE PASSAGE OF MID LEVEL DRY AIR. INSTABILITY WILL DEVELOP BY THE AFTERNOON THROUGH SFC HEATING HOWEVER NO GOOD FORCING MECHANISM WILL BE AVAILABLE AND THIS SHOULD LIMIT THE AREAL COVERAGE OF THUNDERSTORM DEVELOPMENT. THE STRONGER THUNDERSTORMS SATURDAY AFTERNOON AND EVENING WILL INITIALIZE ACROSS NEBRASKA AND KANSAS. THESE STORMS SHOULD MOVE INTO WESTERN IOWA SATURDAY NIGHT AS THE UPPER LEVEL SYSTEM ADVANCES NORTHEAST. A FEW SEVERE STORMS ARE POSSIBLE AS THIS ACTIVITY ARRIVES. THE THUNDERSTORM POTENTIAL ON SUNDAY EARLY IN THE DAY WILL BE FROM LINGERING ACTIVITY FROM THE OVERNIGHT. A BOUNDARY WILL MOVE THROUGH IN THE MORNING AND WILL BRING DRIER AIR TO THE STATE. TEMPERATURES SHOULD WARM IN TO THE 70S AND 80S BEHIND THE BOUNDARY HOWEVER THUNDERSTORM CHANCES WILL BE LIMITED BY THE DRIER AIR. THE BEST POTENTIAL FOR THUNDERSTORMS WILL BE ACROSS NORTHERN IOWA DURING THE AFTERNOON IN CLOSER VICINITY TO THE UPPER LEVEL COLD CORE. AN ATTENDANT HAIL THREAT WOULD BE POSSIBLE WITH ANY AFTERNOON STORMS. THE REMAINDER OF THE EXTENDED WILL BE COOL WITH 850 MB TEMPERATURES IN THE 0-5C RANGE THROUGH WEDNESDAY. BREEZY AND COOL CONDITIONS ON MONDAY. NOT EXPECTING ANY SHOWERS DESPITE THE CYCLONIC FLOW WITH A GOOD INVERSION IN PLACE ABOVE THE BOUNDARY LAYER. ANOTHER PUSH OF COOLER AIR TUESDAY NIGHT AND WEDNESDAY ALONG WITH ANOTHER CHANCE FOR SHOWERS. && .AVIATION...16/06Z ISSUED AT 1127 PM CDT FRI MAY 15 2015 A FEW SHRA/TSRA ARE POSSIBLE OVERNIGHT...BUT COVERAGE TOO LOW FOR INCLUSION IN THE TAFS. OTHERWISE...PRIMARY FORECAST CHALLENGE IS THE POTENTIAL FOR FOG/STRATUS DEVELOPMENT OVERNIGHT. WITH DEWPTS IN THE LOWER 60S AND LOW DEPRESSIONS THERE IS CLEARLY A RISK FOR SUCH REDEVELOPMENT...HOWEVER...SATELLITE IMAGERY SHOWS PRETTY SUBSTANTIAL MID/HIGH LEVEL CLOUDS OVERHEAD AND UPSTREAM...AND THE SURFACE FLOW IS LIGHT BUT ORGANIZED OUT OF THE SOUTHEAST MITIGATING THIS THREAT SOMEWHAT. ALSO NOTE THAT IT IS ALMOST MIDNIGHT ALREADY AND ONLY ONE STATION IN IOWA IS REPORTING LOWER THAN VFR CONDITIONS WITH ALL VSBYS UNRESTRICTED. HAVE THUS OPTED TO GO WITH MVFR BR/CIGS OVERNIGHT BUT WILL BE CLOSELY MONITORING OBSERVATIONAL TRENDS IN CASE AMENDMENTS BECOME NECESSARY. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...CURTIS LONG TERM...DONAVON AVIATION...LEE
***THIS FORECAST DISCUSSION FOCUSES ON SEVERE WEATHER POTENTIAL
TODAY...INCLUDING THE THREAT OF ANOTHER TORNADO OUTBREAK ACROSS THE
HIGH PLAINS.*** TODAY...WIDESPREAD OUTBREAK OF SEVERE WEATHER IS LIKELY AS MANY PIECES COME TOGETHER. OVERALL...FEEL THIS IS ANOTHER DANGEROUS SATURDAY WITH REGARDS TO SEVERE WEATHER AND CLOSE ATTENTION NEEDS TO BE PAID TO LATEST FORECAST UPDATES. SURFACE LOW PRESSURE WILL CONTINUE TO DEEPEN THROUGH THE AFTERNOON HOURS OVER SOUTHEAST COLORADO WITH LITTLE ADVANCEMENT TO THE EAST FORECAST UNTIL AFTER 00Z/6 PM MDT. AHEAD OF THE SURFACE LOW...SOUTHEAST WINDS INCREASE...BECOMING QUITE GUSTY. WITH THE POSITION OF THE LOW AND INCREASING SOUTHEAST WINDS...DO NOT FORESEE AN OPPORTUNITY FOR THE DRYLINE TO RACE EAST AS FORECAST BY MANY HIGH RESOLUTION GUIDANCE MEMBERS. INSTEAD...HAVE USED THE LATEST NAM 12 AS THE BASIS FOR MY FORECAST WHICH INDICATES A NEARLY STATIONARY DRYLINE. BY THIS REASONING...MORE OF TRI-STATE REGION IS UNDER THREAT FOR A HIGHER IMPACT DAY THAN PREVIOUSLY FORECAST. THIS THREAT MAY EVEN EXIST AS FAR WEST AS PORTIONS OF NORTHEAST COLORADO. THREATS: THE THREATS TODAY ARE LARGE HAIL TO BASEBALL SIZE...DAMAGING WINDS AS HIGH AS 70 MPH AND TORNADOES...SOME OF WHICH COULD BE STRONG...LONG-TRACKED TORNADOES. HEAVY RAINS FROM TRAINING STORMS ARE ALSO A CONCERN SO FLASH FLOODING IS A POSSIBILITY. ADDITIONALLY...THESE STORMS WILL PROPAGATE QUICKLY WITH STORM MOTIONS AS FAST AS 50 MPH POSSIBLE. LOCATION: THE HIGHEST CHANCE FOR VIOLENT SUPERCELL THUNDERSTORMS EXTENDS GENERALLY EAST OF THE COLORADO BORDER. PLEASE SEE THE LATEST SPC GRAPHICS FOR BETTER RESOLUTION AS WE STRONGLY AGREE WITH THEIR ASSESSMENT FOR LOCATIONS OF THE ENHANCED AND MODERATE RISK AREAS. TIMING: THERE MAY BE A FEW ROUNDS OF SEVERE WEATHER THIS AFTERNOON. THE FIRST...MOST SIGNIFICANT ROUND BEGINS SHORTLY AFTER NOON. THIS IS WHEN SUPERCELL THUNDERSTORMS WILL DEVELOP ALONG THE DRYLINE AND SPREAD EAST. ANOTHER LINE OF STORMS MAY DEVELOP ALONG THE DRYLINE LATER IN THE AFTERNOON. FINALLY...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER CENTRAL COLORADO AND MOVE ON FROM THE WEST. WHAT YOU NEED TO KNOW: A TORNADO OUTBREAK SEEMS LIKELY TODAY FOR PORTIONS OF THE HIGH PLAINS. CLOSE ATTENTION NEEDS TO BE PAID TO LATEST FORECAST UPDATES AND WATCHES/WARNINGS AS THEY ARE ISSUED TODAY. STORMS...ONCE THEY DEVELOP...WILL ALMOST INSTANTANEOUSLY BECOME SEVERE AND MOVE QUICKLY NORTHEAST. RAPIDLY CHANGING CONDITIONS ARE EXPECTED SO PLEASE BE AWARE OF THIS DEVELOPING WEATHER SITUATION. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 327 AM MDT SAT MAY 16 2015 LATEST GUIDANCE CONTINUES TO INDICATE AN ACTIVE PATTERN ACROSS THE HIGH PLAINS TUESDAY THROUGH SATURDAY. AN UPPER LEVEL LOW WILL MOVE OUT OF THE SOUTHWEST ON TUESDAY AND DEEPEN... CREATING A NEGATIVE TROUGH THAT WILL MOVE NORTHEAST INTO THE REGION AS WE HEAD INTO WEDNESDAY. THE 0- 6KM SHEAR PROFILE IS STRONG WITH 55-65KT ON TUESDAY AND WEDNESDAY AS INDICATED BY BOTH THE GFS AND ECMWF. CAPE VALUES CONTINUE TO REMAIN MODEST WITH THE GLOBAL MODELS INDICATING 200-400 J/KG AT BEST. THE LOW WILL MOVE NORTHWARD THROUGH THE DAY ON WEDNESDAY AND THURSDAY WHICH WILL KEEP POPS IN THE REGION IN THE 20-40 PERCENT RANGE. THE DEVELOPMENT OF SEVERE STORMS WILL BE LIMITED DUE TO THE LOW CAPE AND WEAK THETA-E GRADIENTS HOWEVER WE CANNOT RULE OUT STRONGER THUNDERSTORM DEVELOPMENT AS THE HIGH SHEAR REMAINS IN PLACE. A PERSISTENT TROUGH REMAINS IN PLACE IN THE SOUTHWEST LATE THURSDAY AND EARLY FRIDAY. EARLY GUIDANCE FROM THE GFS AND ECMWF INDICATE A STRONG LOW MOVING SOUTHEASTWARD OUT OF THE PACIFIC LATE FRIDAY AND INTO SATURDAY WHICH WILL REINFORCE AND DEEPEN THIS TROUGH. AT THE SAME TIME LONG FETCH RETURN FLOW WILL INCREASE CAPE VALUES ACROSS THE HIGH PLAINS. CAPE VALUES ON SATURDAY WILL INCREASE TO 800-1200 J/KG WITH LIMITED SHEAR OF 30-40KTS MAINLY IN THE SOUTHERN AREAS OF THE CWA. IT IS VERY EARLY STILL HOWEVER WE CANNOT RULE OUT THE POSSIBILITY OF SEVERE THUNDERSTORMS NEXT SATURDAY AND SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1139 AM MDT SAT MAY 16 2015 BOTH TAF SITES WILL BEGIN TO SEE TRW DEVELOPMENT THIS AFTERNOON IN THE VICINITY OF EACH AIRPORT...LASTING INTO THE EVENING HOURS. BETTER POTENTIAL IS FOR KMCK BY 00Z TONIGHT...WITH HEAVY TRW POSSIBLE FOR A COUPLE OF HOURS. BY 06Z...TRW ACTIVITY WILL DIMINISH WITH VCSH FOR A COUPLE HOURS. OVERALL...MAINLY VFR CONDITIONS IN SCT050-070 UNLESS THUNDER DEVELOPS. WINDS WILL BEGIN AT SSW 20-30KTS...BECOMING WNW AT KGLD BY 02Z SUNDAY AT 15-25KTS...ESPECIALLY AFT 11Z SUNDAY. FOR KMCK...SSW WINDS BEGIN BACKING TO THE SE THRU 00Z TONIGHT THEN SHIFT TO THE WNW BY 06Z TONIGHT AS LOW PRESSURE PASSES REGION...WITH 15-25KTS MAINLY AFTER 16Z SUNDAY...5-15KTS BEFORE THAT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JN SHORT TERM...RRH LONG TERM...TML AVIATION...JN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
205 PM CDT SAT MAY 16 2015 ...UPDATED LONG TERM SECTION... .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 128 PM CDT SAT MAY 16 2015 ABBREVIATED SHORT TERM WITH MET WATCH. MADE ADJUSTMENTS TO POPS CONCERNING THE NON SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL KANSAS EARLY THIS AFTERNOON. SOME OF THE ACTIVITY ACROSS OKLAHOMA HAS BEEN INCREASING IN INTENSITY, SO WILL HAVE TO WATCH OUT FOR MARGINALLY SEVERE BASICALLY SE OF A LINE FROM ASHLAND TO ST JOHN. THE NEXT AREA OF CONCERN IS OUT WEST. BUBBLING CUMULUS HAS BEEN NOTED ON VIS SAT. TOOK A BLEND OF THE HRRR AND WRF-ARW FOR POP ARRANGEMENTS WITH THIS ACTIVITY. WE LAUNCHED AN 18Z RAOB, WHICH LOOKS FAR FROM SPECTACULAR. FIRST, INSTABILITY IS OBVIOUSLY VERY LIMITED WITH ALL LINGERING CLOUD COVER. SECOND, 850-HPA WINDS ARE VERY WEAK. IN FACT, THE ENTIRE LOW LEVELS ARE WEAK, ALTHOUGH THERE IS DECENT VEERING. THIRDLY, UPPER LEVEL WINDS ARE BACKED. TRANSLATION: MESSY HP SUPERCELLS. SO THE SITUATION HAS CHANGED A BIT FROM PREVIOUSLY THOUGHT. THE MORNING SHOWERS AND THUNDERSTORMS WILL PROBABLY HAVE DELETERIOUS IMPACTS TO STORM INTENSITY. RAP ANALYSIS DOES SHOW CAPE INCREASING OUT WEST. STILL THINK WE WILL STILL SEE SEVERE. THINK TORNADO POTENTIAL IS NOT AS HIGH AS PREVIOUSLY THOUGH. THERE IS ENOUGH SHEAR TO GET ROTATING STORMS THOUGH AND A FEW TORNADOES ARE NOT OUT OF THE QUESTION. WHAT IS IN QUESTION IS IF THE TORNADOES WILL BE STRONG OR NOT. HAVE SEEN AN UPTICK ON UPDRAFT HELICITY RECENTLY, SO SOMETHING TO MONITOR. FROM THE 18Z RAOB, IT WILL TAKE QUITE THE ATMOSPHERIC TURN OVER TO GET IT PRIMED FOR STRONG TORNADOES WITH DECENT INSTABILITY AND STRENGTHENING LOW LEVEL WINDS. THERE IS SOME CONCERN ACROSS SOUTH- CENTRAL KANSAS THAT LOW LEVEL WINDS THIS EVENING WILL STRENGTHEN AND THE TORNADO POTENTIAL COULD GO UP. BUT BY THAT TIME, THE STORMS COULD BE OUTFLOWY, PRECIPITATION LADEN MESSY STORMS. WILL CONTINUE TO MONITOR THE MESOSCALE SITUATION AND ADJUST AS NECESSARY. STORMS WILL BE MOVING AT A GOOD CLIP TOO. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 156 PM CDT SAT MAY 16 2015 THE SOUTHERN BRANCH OF THE WESTERLIES WILL CONTINUE TO BE ACTIVE WITH AMPLIFICATION RESULTING FROM TROPICAL CONVECTION ACROSS THE WESTERN PACIFIC. SUNDAY AND MONDAY WILL BE BETWEEN SYSTEMS AND THE ONLY FORECAST CHALLENGE WILL BE TEMPERATURES AS ACTIVELY GROWING VEGETATION AND WET SOILS WILL IMPACT TEMPERATURES. THE NORTHERN BRANCH OF THE WESTERLIES WILL ALLOW SFC HIGH PRESSURE TO BUILD INTO THE AREA MONDAY. WITH THE APPROACH OF ANOTHER S/WV TROUGH IN THE SOUTHERN BRANCH, THE MOIST BOUNDARY LAYER AIR SHOULD BE MOVING BACK NORTHWEST INTO THE HIGHER TERRAIN. WIDESPREAD CONVECTION SHOULD RESULT BY TUESDAY AND INTO WEDNESDAY. YET ANOTHER SYSTEM IS EXPECTED TOWARDS NEXT WEEKEND WITH ADDITIONAL PCPN EXPECTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1200 PM CDT SAT MAY 16 2015 CIGS SHOULD BE PRIMARILY VFR. CANNOT RULE OUT TEMPORARY IFR CONDITIONS LATER THIS AFTERNOON IN ASSOCIATION WITH +TSRA. THIS WILL BE LOCALIZED AND NOT THE PREVAILING FLIGHT CATEGORY. WILL CONTINUE WITH CB/VCTS GROUPS FOR KHYS AND KGCK AND USE A TEMPO GROUP FOR KDDC FOR STORMS THIS EVENING. SOUTHERLY WINDS 15-25 KT TODAY WILL BECOME SOUTHWESTERLY 10-15 KT THROUGH THE OVERNIGHT. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 82 49 70 / 70 0 0 10 GCK 50 80 47 69 / 60 0 0 0 EHA 48 79 47 69 / 10 0 0 0 LBL 50 81 50 73 / 20 0 0 0 HYS 53 80 48 67 / 80 0 0 0 P28 56 83 54 76 / 80 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SUGDEN LONG TERM...HUTTON AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
128 PM CDT SAT MAY 16 2015 ...UPDATED SHORT TERM... .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 128 PM CDT SAT MAY 16 2015 ABBREVIATED SHORT TERM WITH MET WATCH. MADE ADJUSTMENTS TO POPS CONCERNING THE NON SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL KANSAS EARLY THIS AFTERNOON. SOME OF THE ACTIVITY ACROSS OKLAHOMA HAS BEEN INCREASING IN INTENSITY, SO WILL HAVE TO WATCH OUT FOR MARGINALLY SEVERE BASICALLY SE OF A LINE FROM ASHLAND TO ST JOHN. THE NEXT AREA OF CONCERN IS OUT WEST. BUBBLING CUMULUS HAS BEEN NOTED ON VIS SAT. TOOK A BLEND OF THE HRRR AND WRF-ARW FOR POP ARRANGEMENTS WITH THIS ACTIVITY. WE LAUNCHED AN 18Z RAOB, WHICH LOOKS FAR FROM SPECTACULAR. FIRST, INSTABILITY IS OBVIOUSLY VERY LIMITED WITH ALL LINGERING CLOUD COVER. SECOND, 850-HPA WINDS ARE VERY WEAK. IN FACT, THE ENTIRE LOW LEVELS ARE WEAK, ALTHOUGH THERE IS DECENT VEERING. THIRDLY, UPPER LEVEL WINDS ARE BACKED. TRANSLATION: MESSY HP SUPERCELLS. SO THE SITUATION HAS CHANGED A BIT FROM PREVIOUSLY THOUGHT. THE MORNING SHOWERS AND THUNDERSTORMS WILL PROBABLY HAVE DELETERIOUS IMPACTS TO STORM INTENSITY. RAP ANALYSIS DOES SHOW CAPE INCREASING OUT WEST. STILL THINK WE WILL STILL SEE SEVERE. THINK TORNADO POTENTIAL IS NOT AS HIGH AS PREVIOUSLY THOUGH. THERE IS ENOUGH SHEAR TO GET ROTATING STORMS THOUGH AND A FEW TORNADOES ARE NOT OUT OF THE QUESTION. WHAT IS IN QUESTION IS IF THE TORNADOES WILL BE STRONG OR NOT. HAVE SEEN AN UPTICK ON UPDRAFT HELICITY RECENTLY, SO SOMETHING TO MONITOR. FROM THE 18Z RAOB, IT WILL TAKE QUITE THE ATMOSPHERIC TURN OVER TO GET IT PRIMED FOR STRONG TORNADOES WITH DECENT INSTABILITY AND STRENGTHENING LOW LEVEL WINDS. THERE IS SOME CONCERN ACROSS SOUTH- CENTRAL KANSAS THAT LOW LEVEL WINDS THIS EVENING WILL STRENGTHEN AND THE TORNADO POTENTIAL COULD GO UP. BUT BY THAT TIME, THE STORMS COULD BE OUTFLOWY, PRECIPITATION LADEN MESSY STORMS. WILL CONTINUE TO MONITOR THE MESOSCALE SITUATION AND ADJUST AS NECESSARY. STORMS WILL BE MOVING AT A GOOD CLIP TOO. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 234 AM CDT SAT MAY 16 2015 FAIR WEATHER CAN BE EXPECTED SUNDAY IN THE WAKE OF THE AFOREMENTIONED UPPER LEVEL TROUGH, ALONG WITH 10-15 KT SOUTHWEST WINDS AND HIGHS IN THE UPPER 70S TO MID 80S. ANOTHER STRONG UPPER LEVEL STORM SYSTEM WILL PROGRESS INTO THE SOUTHWESTERN UNITED STATES BY LATE MONDAY, AND AHEAD OF THIS FEATURE, A COLD FRONT WILL PASS THROUGH WESTERN KANSAS. HIGH TEMPERATURES WILL FALL INTO THE UPPER 60S MONDAY NEAR INTERSTATE 70, WITH MID 70S IN SOUTH CENTRAL KANSAS. AS THE NEXT UPPER LEVEL STORM SYSTEM APPROACHES ON TUESDAY, LOW LEVEL MOISTURE WILL INCREASE, LEADING TO INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY AND TUESDAY NIGHT. HIGH-END SEVERE STORMS ARE NOT EXPECTED GIVEN THE COOL AIRMASS IN PLACE ACROSS WESTERN KANSAS, BUT MARGINALLY SEVERE ELEVATED THUNDERSTORMS CANNOT BE RULED OUT. HIGH TEMPERATURES WILL PROBABLY BE IN THE UPPER 50S TO 60S TUESDAY. ANOTHER BREAK IN THE RAIN MAY WILL PROBABLY OCCUR WEDNESDAY AND THURSDAY BEFORE THE NEXT UPPER LEVEL SYSTEM APPROACHES FROM THE WEST. HIGHS OUGHT TO BE IN THE 60S TO LOWER 70S WITH LOWS IN THE 40S TO LOWER 50S. WIDESPREAD SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITH THIS SYSTEM FRIDAY AND SATURDAY; AND SOME OF THE STORMS SATURDAY MAY BE SEVERE AS WARMER AND MOIST AIR MOVES INTO WESTERN KANSAS FROM THE SOUTH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1200 PM CDT SAT MAY 16 2015 CIGS SHOULD BE PRIMARILY VFR. CANNOT RULE OUT TEMPORARY IFR CONDITIONS LATER THIS AFTERNOON IN ASSOCIATION WITH +TSRA. THIS WILL BE LOCALIZED AND NOT THE PREVAILING FLIGHT CATEGORY. WILL CONTINUE WITH CB/VCTS GROUPS FOR KHYS AND KGCK AND USE A TEMPO GROUP FOR KDDC FOR STORMS THIS EVENING. SOUTHERLY WINDS 15-25 KT TODAY WILL BECOME SOUTHWESTERLY 10-15 KT THROUGH THE OVERNIGHT. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 82 49 70 / 70 0 0 10 GCK 50 80 47 69 / 60 0 0 0 EHA 48 79 47 69 / 10 0 0 0 LBL 50 81 50 73 / 20 0 0 0 HYS 53 80 48 67 / 80 0 0 0 P28 56 83 54 76 / 80 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SUGDEN LONG TERM...FINCH AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1236 PM CDT Sat May 16 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 346 AM CDT SAT MAY 16 2015 A broad upper level low was located across NV, UT and AZ early this morning. A 65KT mid level jet max was lifting northeast across eastern NM into western KS. The strong ascent ahead of this jet max has helped to develop a line of showers and thunderstorms from central NE, south-southwest into west TX. Most numerical models show this line weakening as it moves east into a more stable airmass across eastern KS through the morning hours. A stronger H5 trough located along the southern base of the upper level low will lift northeast across eastern NM into the northern TX PNHDL through the late morning hours. Several numerical models all show an area of scattered to numerous thunderstorms developing ahead of a surface dryline across the eastern TX PNHDL through the mid and late morning hours. These storms lift northeast and intensify through the early and mid afternoon hours, as they move northeast across western OK into south central KS. The 5Z HRRR shows this area of thunderstorms moving northeast into the western counties of the CWA by 20Z. Most numerical models show the atmosphere destabilizing early this afternoon across the CWA, after the weaker storms from this morning dissipate or lift off to the northeast. the WRF runs, NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks fairly weak with most models forecasting less than 100m2/s2 of 0-1KM SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS during the afternoon. Therefore, the environment will be favorable for severe thunderstorms this afternoon. Another question will be the mode of convection. If a complex of storms develops across northwest OK late this morning and maintains itself northeast across the CWA than any tornado threat will be quite low. Though stronger updrafts within a QLCS or complex of thunderstorms would produce large hail and damaging wind gusts. The HRRR and NAM 4KM simulated reflectivity forecast more scattered to isolated thunderstorms developing across north central OK and south central KS early this afternoon, and moving northeast into the southwest and southern counties of the CWA after 22Z. I suppose if we see discrete supercells than there will be a chance for tornadoes along with the large hail and damaging wind gusts. Late this afternoon most models show thunderstorms developing along the Pacific front/dryline across west central KS and western OK. The environment will really improve ahead of the dryline late this afternoon, with much stronger low-level vertical wind shear. Any discrete supercells that develop along the Pacific front/dryline across west central KS and western OK will have a chance to produce tornadoes. Through the evening hours these discrete to scattered supercell thunderstorms may congeal into line segments or a QLCS and move northeast into the western counties of the CWA during the mid evening hours. If discrete supercells move into the western counties this evening, then there will be a chance for tornadoes. I suppose if a QLCS develops there is a potential for meso-vortices tornadoes. Cloud cover will probably keep high temperatures in the mid to upper 70s. Tonight, The upper low and lead H5 trough will lift northeast into southwest NE. Line segments of thunderstorms or a QLCS will move east across the remainder of the CWA during the late evening hours into the early morning hours of Sunday. The primary hazard will be large hail, damaging winds and heavy rainfall. .LONG TERM...(Sunday through Friday) Issued at 346 AM CDT SAT MAY 16 2015 On Sunday the dry slot will work across the area with lower dewpoints but daytime highs should still reach to around 80 given mixing and expected sun. The cold front will finally move across the area Sunday night and it should pass through dry however there are some signals that precip may develop along it toward Mon morning southeast of the area. For now will keep conds dry and with CAA on Monday expect much cooler highs and lower humidities as dewpoints fall into the 40s. Tues should also remain dry for most of the day with rain expected to overspread the area Tues night and last through Weds. Limited CAPE suggests only isolated thunder but look for another widespread soaking rain out of this system. Perhaps a brief dry spell on Thursday before the next upper wave approaches for late next week into next weekend. This system looks very similar to this weekends so an active pattern will continue. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1234 PM CDT SAT MAY 16 2015 Sites have cleared to VFR after a line of showers moved through the area this morning. VFR should continue until a line of storms moves from SW to NE this afternoon into tonight impacting all terminals. Exact timing and coverage of these storms is still uncertain, and have continued to use VCTS for this reason. Storms will clear overnight into tomorrow morning from W to E. After this clearing VFR will prevail. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gargan LONG TERM...Omitt AVIATION...Heller
AREA FORECAST DISCUSSION
NWS TOPEKA KS
634 AM CDT Sat May 16 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 346 AM CDT SAT MAY 16 2015 A broad upper level low was located across NV, UT and AZ early this morning. A 65KT mid level jet max was lifting northeast across eastern NM into western KS. The strong ascent ahead of this jet max has helped to develop a line of showers and thunderstorms from central NE, south-southwest into west TX. Most numerical models show this line weakening as it moves east into a more stable airmass across eastern KS through the morning hours. A stronger H5 trough located along the southern base of the upper level low will lift northeast across eastern NM into the northern TX PNHDL through the late morning hours. Several numerical models all show an area of scattered to numerous thunderstorms developing ahead of a surface dryline across the eastern TX PNHDL through the mid and late morning hours. These storms lift northeast and intensify through the early and mid afternoon hours, as they move northeast across western OK into south central KS. The 5Z HRRR shows this area of thunderstorms moving northeast into the western counties of the CWA by 20Z. Most numerical models show the atmosphere destabilizing early this afternoon across the CWA, after the weaker storms from this morning dissipate or lift off to the northeast. the WRF runs, NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks fairly weak with most models forecasting less than 100m2/s2 of 0-1KM SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS during the afternoon. Therefore, the environment will be favorable for severe thunderstorms this afternoon. Another question will be the mode of convection. If a complex of storms develops across northwest OK late this morning and maintains itself northeast across the CWA than any tornado threat will be quite low. Though stronger updrafts within a QLCS or complex of thunderstorms would produce large hail and damaging wind gusts. The HRRR and NAM 4KM simulated reflectivity forecast more scattered to isolated thunderstorms developing across north central OK and south central KS early this afternoon, and moving northeast into the southwest and southern counties of the CWA after 22Z. I suppose if we see discrete supercells than there will be a chance for tornadoes along with the large hail and damaging wind gusts. Late this afternoon most models show thunderstorms developing along the Pacific front/dryline across west central KS and western OK. The environment will really improve ahead of the dryline late this afternoon, with much stronger low-level vertical wind shear. Any discrete supercells that develop along the Pacific front/dryline across west central KS and western OK will have a chance to produce tornadoes. Through the evening hours these discrete to scattered supercell thunderstorms may congeal into line segments or a QLCS and move northeast into the western counties of the CWA during the mid evening hours. If discrete supercells move into the western counties this evening, then there will be a chance for tornadoes. I suppose if a QLCS develops there is a potential for meso-vortices tornadoes. Cloud cover will probably keep high temperatures in the mid to upper 70s. Tonight, The upper low and lead H5 trough will lift northeast into southwest NE. Line segments of thunderstorms or a QLCS will move east across the remainder of the CWA during the late evening hours into the early morning hours of Sunday. The primary hazard will be large hail, damaging winds and heavy rainfall. .LONG TERM...(Sunday through Friday) Issued at 346 AM CDT SAT MAY 16 2015 On Sunday the dry slot will work across the area with lower dewpoints but daytime highs should still reach to around 80 given mixing and expected sun. The cold front will finally move across the area Sunday night and it should pass through dry however there are some signals that precip may develop along it toward Mon morning southeast of the area. For now will keep conds dry and with CAA on Monday expect much cooler highs and lower humidities as dewpoints fall into the 40s. Tues should also remain dry for most of the day with rain expected to overspread the area Tues night and last through Weds. Limited CAPE suggests only isolated thunder but look for another widespread soaking rain out of this system. Perhaps a brief dry spell on Thursday before the next upper wave approaches for late next week into next weekend. This system looks very similar to this weekends so an active pattern will continue. && .AVIATION...(For the 12Z TAFs through 12Z Sunday Morning) Issued at 633 AM CDT SAT MAY 16 2015 Currently, TOP/FOE are varying between VFR/MVFR conditions. Have kept prevailing VFR with a tempo MVFR group until 15Z to account for this. At MHK, MVFR conditions are expected to prevail until 19Z when ceilings will lift slightly. A line of TSRA moving slowly east this morning and may reach terminals before weakening, so have mentioned VCTS starting at 15Z at MHK and 17Z at FOE/TOP. The main storms today should be in the afternoon, but timing in hard to pinpoint so have included only VCTS at this time. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gargan LONG TERM...Omitt AVIATION...Heller
AREA FORECAST DISCUSSION
NWS TOPEKA KS
400 AM CDT Sat May 16 2015 .SHORT TERM...(Today and Tonight) Issued at 346 AM CDT SAT MAY 16 2015 A broad upper level low was located across NV, UT and AZ early this morning. A 65KT mid level jet max was lifting northeast across eastern NM into western KS. The strong ascent ahead of this jet max has helped to develop a line of showers and thunderstorms from central NE, south-southwest into west TX. Most numerical models show this line weakening as it moves east into a more stable airmass across eastern KS through the morning hours. A stronger H5 trough located along the southern base of the upper level low will lift northeast across eastern NM into the northern TX PNHDL through the late morning hours. Several numerical models all show an area of scattered to numerous thunderstorms developing ahead of a surface dryline across the eastern TX PNHDL through the mid and late morning hours. These storms lift northeast and intensify through the early and mid afternoon hours, as they move northeast across western OK into south central KS. The 5Z HRRR shows this area of thunderstorms moving northeast into the western counties of the CWA by 20Z. Most numerical models show the atmosphere destabilizing early this afternoon across the CWA, after the weaker storms from this morning dissipate or lift off to the northeast. the WRF runs, NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks fairly weak with most models forecasting less than 100m2/s2 of 0-1KM SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS during the afternoon. Therefore, the environment will be favorable for severe thunderstorms this afternoon. Another question will be the mode of convection. If a complex of storms develops across northwest OK late this morning and maintains itself northeast across the CWA than any tornado threat will be quite low. Though stronger updrafts within a QLCS or complex of thunderstorms would produce large hail and damaging wind gusts. The HRRR and NAM 4KM simulated reflectivity forecast more scattered to isolated thunderstorms developing across north central OK and south central KS early this afternoon, and moving northeast into the southwest and southern counties of the CWA after 22Z. I suppose if we see discrete supercells than there will be a chance for tornadoes along with the large hail and damaging wind gusts. Late this afternoon most models show thunderstorms developing along the Pacific front/dryline across west central KS and western OK. The environment will really improve ahead of the dryline late this afternoon, with much stronger low-level vertical wind shear. Any discrete supercells that develop along the Pacific front/dryline across west central KS and western OK will have a chance to produce tornadoes. Through the evening hours these discrete to scattered supercell thunderstorms may congeal into line segments or a QLCS and move northeast into the western counties of the CWA during the mid evening hours. If discrete supercells move into the western counties this evening, then there will be a chance for tornadoes. I suppose if a QLCS develops there is a potential for meso-vortices tornadoes. Cloud cover will probably keep high temperatures in the mid to upper 70s. Tonight, The upper low and lead H5 trough will lift northeast into southwest NE. Line segments of thunderstorms or a QLCS will move east across the remainder of the CWA during the late evening hours into the early morning hours of Sunday. The primary hazard will be large hail, damaging winds and heavy rainfall. .LONG TERM...(Sunday through Friday) Issued at 346 AM CDT SAT MAY 16 2015 On Sunday the dry slot will work across the area with lower dewpoints but daytime highs should still reach to around 80 given mixing and expected sun. The cold front will finally move across the area Sunday night and it should pass through dry however there are some signals that precip may develop along it toward Mon morning southeast of the area. For now will keep conds dry and with CAA on Monday expect much cooler highs and lower humidities as dewpoints fall into the 40s. Tues should also remain dry for most of the day with rain expected to overspread the area Tues night and last through Weds. Limited CAPE suggests only isolated thunder but look for another widespread soaking rain out of this system. Perhaps a brief dry spell on Thursday before the next upper wave approaches for late next week into next weekend. This system looks very similar to this weekends so an active pattern will continue. && .AVIATION...(For the 06Z TAFs through 06Z Saturday Night) Issued at 1148 PM CDT FRI MAY 15 2015 VFR prevails initially with increased low level moisture bringing in a MVFR stratus deck with haze closer to 10Z according to short term guidance. Line of TSRA in central KS is forecast to weaken west of terminals and will need to monitor trends. Scattered TSRA are possible after 15Z at KTOP/KFOE where VCTS mention is placed. Believe the better forcing arrives late afternoon/early evening where storms develop in central KS and track east through the evening. Confidence in timing or duration is too uncertain to mention at this time. Gusty south winds prevail throughout period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gargan LONG TERM...Omitt AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1202 AM CDT SAT MAY 16 2015 ...UPDATE TO AVIATION... .SYNOPSIS... ISSUED AT 1102 PM CDT FRI MAY 15 2015 WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE A BROAD UPPER LEVEL TROUGH OF LOW PRESSURE PUSHING SLOWLY EAST ACROSS THE GREAT BASIN REGION. MEANWHILE, AN H5 VORT MAXIMA IS CYCLING EASTWARD ACROSS THE DESERT SOUTHWEST WITHIN THE BROADER SCALE TROUGH. NEAR THE SURFACE, AN AREA OF LOW PRESSURE IS POSITIONED ACROSS NORTHEASTERN COLORADO WITH AN ATTENDANT TROUGH AXIS EXTENDING SOUTHWARD ALONG THE KANSAS AND COLORADO BORDER. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 141 PM CDT FRI MAY 15 2015 RAP AND NGM BOTH SUPPORTING A SURFACE BOUNDARY EXTENDING FROM NEAR HAYS TO COLDWATER AT 00Z SATURDAY WITH WEAK 0-1KM MOISTURE CONVERGENCE OCCURRING ALONG THIS BOUNDARY. 0-6KM SHEAR IN THIS AREA WILL BE FROM 20 TO 25 KNOTS AND CAPE VALUES ARE EXPECTED TO RANGE FROM 1000 TO 1500 J/KG. RAP HAS SOME CIN REMAINING IN THIS AREA GIVEN THE WARM MID LEVEL TEMPERATURES WHILE THE NAM SUGGESTS A FEW ISOLATED THUNDERSTORMS BEING POSSIBLE. AT THIS TIME GIVEN THE CU DEVELOPING WILL RETAIN MENTION OF ISOLATED THUNDERSTORMS GOING ALONG AND EAST OF THIS BOUNDARY EARLY TONIGHT. ANOTHER AREA OF THUNDERSTORMS WILL DEVELOP EARLY THIS EVENING NEAR THE COLORADO BORDER. THIS AREA WILL HAVE MORE FAVORABLE UPPER LEVEL DYNAMICS ALONG WITH IMPROVING WARM AIR ADVECTION NEAR THE NOSE OF A 50 KNOT 850MB JET BASED ON THE 12Z NAM. THESE STORMS WILL MARCH EAST ACROSS WESTERN KANSAS OVERNIGHT WITH A FEW OF THESE STORMS BEING CAPABLE OF PRODUCING SMALL HAIL AND WIND GUSTS OF UP TO 55 MPH. BY EARLY SATURDAY MORNING THIS THUNDERSTORM ACTIVITY WILL BE MOVE INTO CENTRAL KANSAS AS AN UPPER LEVEL TROUGH CROSSES EASTERN COLORADO AND NORTHEAST NEW MEXICO. 12Z NAM SHOWING 0-6KM SHEAR SATURDAY AFTERNOON RANGING FROM 40 TO NEAR 50 KNOTS AND CAPE VALUES WILL RANGING FROM 1500 TO 2500 J/KG AHEAD OF THIS UPPER LEVEL SYSTEM. THIS CONTINUES TO SUPPORT THE CHANCE FOR SEVERE THUNDERSTORMS ALONG AND EAST OF WHERE THIS DRY LINE WILL BE LOCATED BETWEEN 18Z AND 21Z SATURDAY. LARGE HAIL AND STRONG DAMAGING WINDS CURRENTLY APPEARS TO BE THE MAIN HAZARD ALONG WITH PERIODS OF HEAVY RAINFALL. A FEW TORNADOES WILL ALSO BE POSSIBLE LATE SATURDAY AND EARLY SATURDAY NIGHT. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 141 PM CDT FRI MAY 15 2015 EVENING CONVECTION WILL TAPER OFF EARLY SATURDAY NIGHT AS THE UPPER LEVEL TROUGH LIFTS NORTHEAST INTO NORTH CENTRAL KANSAS AND THE DRY LINE/COLD FRONT MOVES SOUTH AND EAST. WESTERLY DOWNSLOPE FLOW WILL DEVELOP BY EARLY SUNDAY MORNING AND CONTINUE THROUGH THE REMAINDER OF THE WEEKEND AS ANOTHER UPPER LEVEL TROUGH MOVES OUT OF SOUTHERN WYOMING AND INTO THE CENTRAL HIGH PLAINS. 700MB TO 500MB LAPSE RATES WILL VARY FROM 7 TO 8C/KM AHEAD OF THIS UPPER WAVE, HOWEVER MOISTURE APPEARS SOMEWHAT LIMITED EARLY SUNDAY NIGHT. ALTHOUGH A FEW SPRINKLE MAY BE POSSIBLE NEAR AND NORTH OF THE INTERSTATE 70 CORRIDOR, AT THIS TIME WILL ONLY INCREASE CLOUD COVER AT THIS TIME SUNDAY EVENING GIVEN THE LIMITED MOISTURE IN THE LOWER LEVELS. GIVEN THE WESTERLY DOWNSLOPE FLOW AND 850MB TEMPERATURES AT 00Z MONDAY WILL RANGING FROM 18C TO NEAR 24C THE PREVIOUS FORECAST STILL LOOKS ON TRACK WITH HIGHS RANGING FROM THE UPPER 70S IN WEST CENTRAL KANSAS TO THE LOWER 80S IN SOUTH CENTRAL KANSAS. EARLY NEXT WEEK AN UPPER LEVEL RIDGE AXIS WILL CROSS WESTERN KANSAS AS AN AREA OF HIGH PRESSURE AT THE SURFACE BUILDS INTO KANSAS PLAINS. TEMPERATURES ON MONDAY WILL AVERAGE AROUND 10F COOLER WHEN COMPARED TO THE HIGHS ON SUNDAY GIVEN THE 900 TO 850MB TEMPERATURE TRENDS FROM 00Z MONDAY AND 00Z TUESDAY. CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS AN UPPER LEVEL TROUGH/LOW MOVES EAST ACROSS THE SOUTHWEST UNITED STATES. IN ADDITION TO THE INCREASING CLOUDS THERE WILL ALSO BE A CHANCE FOR PRECIPITATION TO DEVELOP BY EARLY TUESDAY GIVEN A MOIST SOUTHEASTERLY UPSLOPE FLOW, WARM AIR ADVECTION, AND IMPROVING ISENTROPIC LIFT ACROSS SOUTHWEST KANSAS. HIGH PRECIPITATION CHANCES WILL CONTINUE THROUGH MID WEEK AS THE UPPER LEVEL SYSTEM WEAKENS AND MOVES EAST NORTHEAST INTO THE CENTRAL PLAINS. TEMPERATURES THROUGH MID WEEK WILL STAY ON THE COOL SIDE GIVEN THE CLOUD COVER AND HIGH PRECIPITATION CHANCES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1200 AM CDT SAT MAY 16 2015 SHOWERS AND ISOLATED THUNDERSTORMS WILL SPREAD NORTHEAST ACROSS SOUTHWEST AND CENTRAL KANSAS OVERNIGHT POTENTIALLY AFFECTING ALL TAF SITES. OTHERWISE, VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH EARLY SATURDAY AFTERNOON. SCATTERED THUNDERSTORMS WILL BE POSSIBLE AGAIN LATE SATURDAY AFTERNOON, GENERALLY IN THE VICINITY OF KGCK AND TO THE EAST. A SURFACE LOW WILL REMAIN ANCHORED ACROSS NORTHEASTERN COLORADO OVERNIGHT WITH AN ATTENDANT TROUGH AXIS EXTENDING SOUTHWARD NEAR AND ALONG THE COLORADO BORDER. THIS WILL RESULT IN SOUTHERLY WINDS OF 10 TO 20KT PERSISTING ACROSS WESTERN KANSAS THROUGH LATE SATURDAY MORNING. THE SURFACE LOW IS THEN EXPECTED TO DEEPEN ACROSS NORTHEASTERN COLORADO SATURDAY AFTERNOON INCREASING WINDS UP TO AROUND 25 TO 35KT. && .PRELIMINARY POINT TEMPS/POPS... DDC 53 82 50 69 / 40 0 0 10 GCK 51 79 47 69 / 20 0 0 0 EHA 49 79 47 69 / 10 0 0 0 LBL 51 81 50 71 / 20 0 0 0 HYS 54 79 50 67 / 60 0 0 0 P28 58 83 54 72 / 50 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJOHNSON SHORT TERM...BURGERT LONG TERM...BURGERT AVIATION...JJOHNSON
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1030 PM EDT SUN MAY 17 2015 .UPDATE... ISSUED AT 1030 PM EDT SUN MAY 17 2015 THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN ISSUED. UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015 23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER... AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK. FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 300 PM EDT SUN MAY 17 2015 THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH 0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING. TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 300 PM EDT SUN MAY 17 2015 MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY NIGHT INTO EARLY THURSDAY. IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48 HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION. A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE IN THE WEEK...DY6 FRI. THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS. THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE END OF THE FORECAST WINDOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 800 PM EDT SUN MAY 17 2015 THE MAIN CONCERN WITH THIS UPDATE TO THE TAFS REVOLVE AROUND THE DOWNSTREAM IMPACTS OF THE INBOUND ARC OF STORMS AND TRAILING RAINS HEADED FOR THE JKL CWA. HAVE TIMED THIS THROUGH THE TAF SITES WITH IFR AND MVFR VIS/CIGS ALONG WITH GUSTY WINDS AS IT PASSES... DIMINISHING WITH TIME AND DISTANCE WHILE PROGRESSING EAST. FOLLOWING THE BAND OF STORMS/RAINS...PATCHY FOG WILL BE THE NEXT CONCERN AND HAVE INCLUDED AT LEAST SOME MVFR VIS AT THE SITES THROUGH 13Z. FOR MONDAY...ANTICIPATE A SIMILAR DAY WITH CONVECTION DEVELOPING FROM THE HEATING MAKING STORMS POSSIBLE IN THE AFTERNOON. OUTSIDE OF ANY STORMS...THE WINDS WILL BE LIGHT FROM THE SOUTH TO SOUTHWEST TONIGHT BEFORE PICKING UP AT 5 TO 10 KTS BY MIDDAY MONDAY...ALONG WITH SOME GUSTS TO 15 KTS POSSIBLE IN THE AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
800 PM EDT SUN MAY 17 2015 .UPDATE... ISSUED AT 730 PM EDT SUN MAY 17 2015 23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER... AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK. FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 300 PM EDT SUN MAY 17 2015 THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH 0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING. TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 300 PM EDT SUN MAY 17 2015 MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY NIGHT INTO EARLY THURSDAY. IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48 HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION. A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE IN THE WEEK...DY6 FRI. THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS. THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE END OF THE FORECAST WINDOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 800 PM EDT SUN MAY 17 2015 THE MAIN CONCERN WITH THIS UPDATE TO THE TAFS REVOLVE AROUND THE DOWNSTREAM IMPACTS OF THE INBOUND ARC OF STORMS AND TRAILING RAINS HEADED FOR THE JKL CWA. HAVE TIMED THIS THROUGH THE TAF SITES WITH IFR AND MVFR VIS/CIGS ALONG WITH GUSTY WINDS AS IT PASSES... DIMINISHING WITH TIME AND DISTANCE WHILE PROGRESSING EAST. FOLLOWING THE BAND OF STORMS/RAINS...PATCHY FOG WILL BE THE NEXT CONCERN AND HAVE INCLUDED AT LEAST SOME MVFR VIS AT THE SITES THROUGH 13Z. FOR MONDAY...ANTICIPATE A SIMILAR DAY WITH CONVECTION DEVELOPING FROM THE HEATING MAKING STORMS POSSIBLE IN THE AFTERNOON. OUTSIDE OF ANY STORMS...THE WINDS WILL BE LIGHT FROM THE SOUTH TO SOUTHWEST TONIGHT BEFORE PICKING UP AT 5 TO 10 KTS BY MIDDAY MONDAY...ALONG WITH SOME GUSTS TO 15 KTS POSSIBLE IN THE AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
208 PM CDT SAT MAY 16 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 208 PM CDT SAT MAY 16 2015 LOCALLY HEAVY RAIN IN PARTS OF WEST KY WITH AMOUNTS SINCE MIDNIGHT 1-2" IN A FEW SPOTS...MOSTLY AT OR BELOW 1". AREAL FLOOD ADVISORIES WILL SUFFICE GIVEN THE PROGRESSIVE NATURE OF THE ACTIVITY AND THE DOWNWARD TREND EXPECTED OVERALL. LITTLE TO NO LIGHTNING...DEFINITELY EFFICIENT NONE THE LESS GIVEN WEAK LAPSE RATES AND SMALL CAPE. ALL THE MODELS POINT TO A DIMINISHING TREND FOR THE OVERNIGHT IN THE WAKE OF THIS WAVE THAT WE HAVE MONITORED ON WVAPOR MOVING SLOWLY NE. THE RAP AND NAM WERE GENERALLY FOLLOWED. WE CONTINUE TO HOLD TEMPS DOWN THE REST OF TODAY AS WELL. THEY SHOULD FALL LITTLE TONIGHT WITH THE STAGNANT/HUMID AIRMASS IN PLACE AND SOUTHERLY FLOW THE RULE. SPC EXPANDED THEIR SLIGHT RISK AREA EAST DAY 2 INTO 1/2 OF THE AREA FROM THE WEST. THIS SEEMS OVERDONE AND TEND TO DISAGREE. SURE THERE COULD BE A FEW WARNINGS. BUT ENOUGH QUESTION MARKS EXIST. THE NAM SUGGESTS A MIN CORRIDOR OF WEAK INSTABILITY ACROSS MUCH OF THE AREA SUNDAY WITH CONVECTION AND CLOUDS ALREADY INTO THE AREA AND BETTER DESTABILIZATION TO OUR WEST AND EAST. THE GFS AND ECMWF SHOW BETTER DESTABILIZATION THROUGH THE DAY. EVEN IF WE DESTABILIZE... BETTER WIND FIELDS ARE POSITIONED TO OUR WEST AND NORTH AND NOT SUPPORTIVE OF SUSTAINED ORGANIZATION. WILL KEEP POPS HIGH CHANCE GIVEN UNCERTAINTY WITH RESPECT TO COVERAGE. SHOULD BE WARMER THAN TODAY. SUNDAY NIGHT THROUGH MONDAY EVENING...WILL CONTINUE WITH HIGH CHANCE TO LOW END LIKELY POPS FOR CONVECTION...AS THE FRONT VERY SLOWLY WORKS SOUTH INTO THE AREA BY MONDAY EVENING/NIGHT. BEST CHANCES WILL EVENTUALLY FOCUS ACROSS THE SOUTHEAST 1/2 TO 2/3 OF THE AREA. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 208 PM CDT SAT MAY 16 2015 HIGHER THAN AVERAGE CONFIDENCE IN THE EXTENDED. MODELS AND ENSEMBLES IN FAIR AGREEMENT WITH THE EXTENDED FORECAST. SURFACE HIGH PRESSURE WILL BE THE MAIN SYNOPTIC SCALE FEATURE IN CONTROL. HOWEVER THERE WILL BE A WEAK PERTURBATION IN THE NEARLY ZONAL FLOW ALOFT WITH A REFLECTION OF A SURFACE LOW PASSING JUST TO OUR SOUTH. THIS WILL BRING AT LEAST A CHANCE OF SHOWERS TO THE AREA WEDNESDAY. SURFACE BASED CONVECTION LOOKS UNLIKELY WITH POSITIVE LI`S AND LITTLE TO NO CAPE. ALTHOUGH SHOWALTERS IN VERY POSITIVE...K INDEX VALUES ARE IN THE MID 20S. SO WILL NOT RULE OUT A CLAP OF THUNDER BUT NOTHING IMPRESSIVE AT THIS TIME. OTHERWISE HIGH PRESSURE WILL BE THE DOMINANT FEATURE AFTER THE PASSAGE OF THIS SURFACE LOW. TEMPERATURES WILL BE AT SLIGHTLY BELOW NORMAL IN THE EXTENDED WITH WINDS RELATIVELY LIGHT AFTER WEDNESDAY. && .AVIATION... ISSUED AT 208 PM CDT SAT MAY 16 2015 WILL MAINTAIN CONVECTIVE CHANCES THROUGH MID TO LATE AFTERNOON. OVERNIGHT EXPECT A DOWNWARD TREND IN COVERAGE...SO NO INCLUSION FOR THE OVERNIGHT INTO THE MORNING SUNDAY. LOW CONFIDENCE IN BASE HEIGHTS OVERNIGHT. GENERALLY STAYED MVFR THROUGH VARIABILITY IS NOT OUT OF THE QUESTION. SOUTH WINDS TO PERSIST...WITH GUSTS 15-20 KTS DEVELOPING SUNDAY MORNING. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1032 PM CDT SUN MAY 17 2015 .UPDATE... TO MAKE ADJUSTMENTS TO THE RAIN CHANCES TONIGHT THROUGH MONDAY NIGHT AND CONTINUED THE THREAT FOR FLASH FLOODING FOR EAST AND NORTHEAST TEXAS...NORTHWEST AND NORTH CENTRAL LOUISIANA AND ADJACENT SOUTHWEST AND SOUTH CENTRAL ARKANSAS AND SOUTHEAST OKLAHOMA. && .DISCUSSION... A CONTINUED SOUTHERLY FLOW OF GULF MOISTURE TO GO ALONG WITH A CONTRIBUTING SUPPLY OF PACIFIC MOISTURE AND A SERIES OF UPPER LEVEL DISTURBANCES RIDING TOWARD THE FOUR STATE REGION WILL CONTINUE TO PROVIDE SHOWERS AND THUNDERSTORMS OVERNIGHT. SOME OF THE STORMS WILL DEVELOP AND SPREAD OVER THE SAME AREAS THAT HAVE HAD LOCALLY HEAVY RAIN LATELY RESULTING IN FLASH FLOODING. /06/ && .PREV DISCUSSION... /ISSUED 630 PM CDT SUN MAY 17 2015/ AVIATION... AREAL TERMINAL SITES ALL REPORTING VFR CONDITIONS AS CONVECTION HAS SHIFTED TO THE EAST AND TO THE SOUTH OF THE REGION...WITH MOSTLY MID AND UPPER LVL CIGS REMAINING. MCS DEVELOPMENT PROGGED TO POSSIBLY MOVE INTO THE KTXK...KTYR...AND KGGG VCNTYS AFTER 18/04Z...AND BECOME MORE ORGANISED ACROSS THE LA TERMINALS AT KSHV AND KMLU BTWN 18/06-08Z. HOWEVER...AIRMASS CURRENTLY WORKED OVER SO TIMING OF REDEVELOPMENT IN QUESTION. SOME PATCHY FOG POSSIBLE FROM WET GROUND AND LIGHT WINDS OVERNIGHT...ESPECIALLY WHERE UPPER LVL CLOUDS THIN OUT. WINDS TO REMAIN WELL BELOW 10 KTS AREAWIDE THRU PERIOD...AND MOSTLY SOUTHERLY./VII/. PREV DISCUSSION... /ISSUED 455 PM CDT SUN MAY 17 2015/ DISCUSSION... MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL- DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE DIFFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT. HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0 INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE. AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY. THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH THE MAIN ATTENDENT TROUGH LIFTING NE INTO THE SRN ROCKIES BY EARLY TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH WILL HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE SRN PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH THE FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT TERM PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING SW INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING STATIONARY. PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE GFS...WHICH SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS ALOFT TO HELP DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP FOCUS SCT CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER ISOLATED TO WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY. HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE CLIMO THROUGH MUCH OF THE PERIOD. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 71 82 70 86 / 70 70 30 30 MLU 72 81 69 86 / 60 70 40 40 DEQ 68 83 67 82 / 50 40 40 30 TXK 70 83 68 83 / 60 50 40 30 ELD 70 81 68 84 / 70 70 40 30 TYR 71 82 69 85 / 60 50 30 30 GGG 70 82 69 86 / 70 60 30 30 LFK 72 82 71 88 / 40 70 30 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR ARZ050-051- 059>061-070>073. LA...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR LAZ001>006- 010>012. OK...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OKZ077. TX...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR TXZ096-097- 108>112-124>126-136>138-149>153. && $$ 06
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
630 PM CDT SUN MAY 17 2015 .AVIATION... AREAL TERMINAL SITES ALL REPORTING VFR CONDITIONS AS CONVECTION HAS SHIFTED TO THE EAST AND TO THE SOUTH OF THE REGION...WITH MOSTLY MID AND UPPER LVL CIGS REMAINING. MCS DEVELOPMENT PROGGED TO POSSIBLY MOVE INTO THE KTXK...KTYR...AND KGGG VCNTYS AFTER 18/04Z...AND BECOME MORE ORGANISED ACROSS THE LA TERMINALS AT KSHV AND KMLU BTWN 18/06-08Z. HOWEVER...AIRMASS CURRENTLY WORKED OVER SO TIMING OF REDEVELOPMENT IN QUESTION. SOME PATCHY FOG POSSIBLE FROM WET GROUND AND LIGHT WINDS OVERNIGHT...ESPECIALLY WHERE UPPER LVL CLOUDS THIN OUT. WINDS TO REMAIN WELL BELOW 10 KTS AREAWIDE THRU PERIOD...AND MOSTLY SOUTHERLY./VII/. && .PREV DISCUSSION... /ISSUED 455 PM CDT SUN MAY 17 2015/ DISCUSSION... MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL- DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE DIFFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT. HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0 INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE. AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY. THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH THE MAIN ATTENDENT TROUGH LIFTING NE INTO THE SRN ROCKIES BY EARLY TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH WILL HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE SRN PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH THE FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT TERM PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING SW INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING STATIONARY. PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE GFS...WHICH SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS ALOFT TO HELP DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP FOCUS SCT CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER ISOLATED TO WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY. HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE CLIMO THROUGH MUCH OF THE PERIOD. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 71 82 70 86 / 70 70 30 30 MLU 72 81 69 86 / 60 70 30 40 DEQ 68 83 67 82 / 60 40 30 30 TXK 70 83 68 83 / 70 50 30 30 ELD 70 81 68 84 / 70 70 30 30 TYR 71 82 69 85 / 60 50 20 30 GGG 70 82 69 86 / 70 60 20 30 LFK 72 82 71 88 / 40 70 20 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY AFTERNOON FOR ARZ050-051-059>061-070>073. LA...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY AFTERNOON FOR LAZ001>006-010>012. OK...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY AFTERNOON FOR OKZ077. TX...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY AFTERNOON FOR TXZ096-097-108>112-124>126-136>138-149>153. && $$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
406 PM CDT SAT MAY 16 2015 SHORT TERM...NOT MUCH HAS CHANGED FROM 24 HOURS AGO. STILL IN QUITE AN ACTIVE CONVECTIVE DAY WITH WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS IMPACTING THE CWA EXCEPT FOR AREAS SOUTH OF INTERSTATE 10. THINKING THAT SINCE THE ENVIRONMENT IS SO SIMILAR...ACTIVITY MAINTAINABILITY WILL GO WELL INTO THE AFTERNOON AND EVENING HOURS AGAIN. HRRR SHOWS STORMS GOING PAST MIDNIGHT EAST OF I-55. MAIN THREAT WILL BE HEAVY RAIN AND POSSIBLE FLASH FLOODING AS SOME TRAINING HAS BEEN OCCURRING. OTHERWISE...TYPICAL MARITIME ENVIORNMENT IN PLACE POSES THE THREAT FOR WATERSPOUTS WHICH CAN ON OCCASION MOVE ONSHORE. SYNOPTICALLY SPEAKING...AN UPPER LEVEL TROUGH IS IN THE PROCESS OF SWINGING ACROSS THE ROCKIES AND WILL REACH THE UPPER MISSISSIPPI VALLEY BY LATE TOMORROW. THE WESTERN ATLANTIC AND EASTERN GULF OF MEXICO WILL REMAIN UNDER AN UPPER RIDGE DURING THIS TIME. THE LOCAL CWA BEING CAUGHT BETWEEN THESE 2 FEATURES WHICH WILL BE A FUNNEL ZONE OF MOISTURE AND WEAK SHORTWAVES. DAYTIME POPS INTO TOMORROW STILL AT ABOUT 50 PERCENT. MEFFER && .LONG TERM...A WEAK FRONTAL BOUNDARY WILL SAG INTO THE AREA GOING INTO TUESDAY. A GENERAL WEAK SURFACE TROUGH WILL BE THE FOCUS FOR ENHANCED CONVECTION THROUGH JUST ABOUT THE ENTIRE WEEK WITH AT LEAST 40 PERCENT FOR DAILY POPS. UPPER LEVEL RIDGE WILL TRY TO REASSERT ITSELF OVER THE REGION LATE WEEK AND INTO THE WEEKEND WHICH WOULD LOWER POPS AND INCREASE TEMPS. UPPER 80S TO NEAR 90 DEGREES COULD BE COMING THEN. MEFFER && .AVIATION... SHOWERS AND THUNDERSTORMS WILL GENERALLY BE A POTENTIAL IMPACT TO TERMINALS NORTH OF A KNEW TO KHUM LINE THROUGH THE NEXT SEVERAL HOURS BEFORE STARTING TO WIND DOWN. IN ADDITION...STRONG SOUTHEAST WINDS WILL RELAX QUITE A BIT ONCE THE SUN BEGINS TO SET. VFR CONDITIONS EXPECTED ONCE THE CONVECTION WANES THIS EVENING. KGPT AND KASD WILL BE THE LAST TO BE CONVECTION FREE AND THAT MAY NOT HAPPEN UNTIL LATE TONIGHT. MEFFER && .MARINE...CURRENT WINDS OVER OFFSHORE WATERS ARE RIGHT AT OR JUST ABOVE 15 KNOTS...SO REISSUING EXERCISE CAUTION THRU TONIGHT. CURRENT SYNOPSIS SHOWS SURFACE RIDGE CENTERED JUST OFF THE CAROLINA COASTS EXTENDS WELL INTO THE GULF OF MEXICO WHICH HAS ESTABLISHED ONSHORE FLOW. THIS HIGH WILL SLOWLY WEAKEN AS IT SAGS SOUTH TOWARDS FLORIDA. LOCAL WINDS WILL FOLLOW THIS WEAKENING TREND AS WELL...FALLING TO LESS THAN 10 KNOTS ON TUESDAY. WEAK WIND FIELD WILL REMAIN IN PLACE AS A COLD FRONT STALLS ALONG THE NORTHERN GULF COAST MID WEEK AND A RAGGED SURFACE HIGH TRIES TO ESTABLISH ITSELF OVER THE GULF OF MEXICO. COULD RETURN TO MORE CONSISTENT SOUTHEASTERLY WINDS NEXT WEEKEND. MEFFER && DSS CODE...GREEN. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...NONE. DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 71 85 71 85 / 40 50 20 60 BTR 73 87 73 87 / 40 50 20 60 ASD 74 85 73 86 / 40 40 20 50 MSY 75 86 75 86 / 40 40 20 50 GPT 75 84 75 84 / 50 40 20 30 PQL 73 84 73 84 / 50 40 10 40 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1145 PM CDT FRI MAY 15 2015 .MESOSCALE UPDATE... AREAL FLOOD ADVISORIES WILL BE ALLOWED TO EXPIRE AS ISSUED...MIDNIGHT FOR SOUTH SHORE POLYGON AND 115 AM FOR NORTH SHORE POLYGON. CONVERGENT BOUNDARY SHOULD WEAKEN WHILE OUTFLOW BECOMES A MORE DOMINANT PLAYER OVERNIGHT FOR PROPAGATION OF STORM INTO THE MISSISSIPPI COASTAL COUNTIES OVERNIGHT. HRRR MODEL RUN FAVORS THIS SOLUTION AND MAY WARRANT ADDITIONAL ISSUANCES OF FLOOD ADVISORIES...POSSIBLE FLASH FLOOD WARNINGS SHOULD A CONVERGENCE AXIS BECOME ESTABLISHED FOR ANY SIGNIFICANT DURATION TONIGHT AND EARLY SATURDAY MORNING. 24/RR .AVIATION... ONLY TERMINALS CURRENTLY WITH CONVECTIVE IMPACTS ARE KMSY AND KASD AND EXPECTING DIMINISHING COVERAGE NEXT 1-2 HOURS. MEANWHILE...KGPT AND KPQL HAVE HAD MINIMAL INFLUENCES FROM AREAL CONVECTION TODAY AND MAY BE PRONE TO NOCTURNAL DEVELOPMENTS BETWEEN 06-11Z. MVFR CONDITIONS AT MOST LOCATIONS TONIGHT IMPROVING TO LOW END VFR CIGS OUTSIDE CONVECTION SATURDAY. GUST POTENTIAL SOULD BE AROUND 30 KT WITH THE INITIAL STRONGER STORMS BETWEEN 16Z-18Z CAPABLE OF WET MICROBURST GUSTS 40-45 KT...AND FAVORED IN WESTERN TAFS LIKE KBTR AND KMCB WHERE MOISTURE RECOVERY WILL BE GREATEST. 24/RR && .PREV DISCUSSION... /ISSUED 840 PM CDT FRI MAY 15 2015/ ..SOUNDING DISCUSSION... ATMOSPHERE IS JUICY TONIGHT WITH A PRECIPITABLE WATER /PW/ VALUE OVER 2 STANDARD DEVIATIONS ABOVE NORMAL AT 2.14 INCHES. THIS DESTROYS THE OLD RECORD PW VALUE FOR THIS DATE AND TIME OF 1.8 INCHES AS FOUND ON THE SPC PW CLIMATOLOGY PAGE. THE TROPICAL MOISTURE IS BEING DRAWN INTO THE AREA ON SOUTHERLY WINDS AVERAGING 20 TO 25 KNOTS IN THE LOW AND MID-LEVELS. A PEAK WIND SPEED OF 52 KNOTS WAS FOUND AT 46200 FEET. THERE IS A FAIR AMOUNT OF INSTABILITY IN THE ATMOSPHERE...WHICH MAY ALLOW SHOWERS AND THUNDERSTORMS TO LAST UNTIL AROUND OR PERHAPS AN HOUR OR TWO AFTER MIDNIGHT. 00Z BALLOON INFO: LAUNCH WAS DELAYED A BIT DUE TO LIGHTNING IN THE AREA...BUT OTHERWISE A ROUTINE FLIGHT. THE BALLOON ASCENDED FOR 74 MINUTES WHILE TRAVELING 13 MILES DOWNRANGE BURSTING EAST OF NICHOLSON AT A HEIGHT OF 15.1 MILES ABOVE THE GROUND. ANSORGE PREV DISCUSSION... /ISSUED 354 PM CDT FRI MAY 15 2015/ PREVIOUS LONG TERM...LITTLE CHANGE IN THE LONG TERM FORECAST PATTERN WITH CHANCES OF SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE WORK WEEK. BLENDED GUIDANCE WILL BE USED WITH MAINLY CHANCE/SCATTERED RAINFALL CHANCES DURING THE DIURNALLY FAVORED TIME PERIODS. ALSO LITTLE DAY TO DAY TEMPERATURE CHANGE WITH THE EXCEPTION OF THOSE SITES SEEING CONVECTION EARLY IN THE DAY. 35 AVIATION... SHOWERS AND THUNDERSTORMS WILL GENERALLY BE A POTENTIAL IMPACT TO TERMINALS THROUGH THE NEXT FEW HOURS BEFORE STARTING TO WIND DOWN AFTER AROUND 02Z. SO WILL CARRY -RA AND TEMPO TSRA IN MOST TAFS THRU THIS AFTN. OVERNIGHT CONDITIONS WILL RANGE FROM MVFR TO IFR CEILINGS. MEFFER MARINE... HIGH PRESSURE OVER THE EAST COAST WILL MAINTAIN A SOUTHEASTERLY FLOW THROUGH MONDAY. THE PRESSURE GRADIENT WILL KEEP OFFSHORE WATERS RIGHT AT THE THRESHOLD FOR EXERCISE CAUTION. IT DOES APPEAR IT WILL BE EXCEEDED TONIGHT...SO GOING IT HAVE THE SCS HEADLINE IN GRIDS THEN. THE HIGH WILL MOVE INTO THE GULF EARLY NEXT WEEK CAUSING WIND SPEEDS TO LOWER EVEN MORE WITH A LIGHT BREEZE OUT OF THE WEST BY WED. EACH DAY WILL BRING A GOOD CHANCE OF SH/TS THROUGH THE MIDDLE OF NEXT WEEK. MEFFER DSS CODE...GREEN. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...NONE. DECISION SUPPORT SERVICES (DSS) CODE LEGEND GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH VISIBILITY EVENT YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE && .PRELIMINARY POINT TEMPS/POPS... MCB 70 83 71 85 / 50 60 50 50 BTR 71 85 72 86 / 40 60 50 50 ASD 72 83 73 85 / 50 60 50 50 MSY 73 84 75 85 / 40 60 50 50 GPT 74 82 75 84 / 50 60 40 40 PQL 72 82 73 84 / 50 60 50 50 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1132 PM CDT FRI MAY 15 2015 .AVIATION...LOW LEVEL WIND FIELD WILL BE STRENGTHENING OVERNIGHT ACROSS THE AREA BRINGING IN WIDESPREAD MVFR CLOUDINESS. ENHANCED LIFT AHEAD OF AN APPROACHING MID/UPPER TROF WILL MAINTAIN A FEW SHOWERS OVER ACADIANA. MAINTAINING VCSH THROUGH THE NIGHT AT ARA AND LFT. PASSAGE OF AFOREMENTIONED TROF AND DRIER AIR IN ITS WAKE WILL RESULT IN LESS CONVECTION SATURDAY THAN TODAY FOR THE AREA. WILL KEEP VCSH FOR THE MORNING AT ALL TERMINALS AND VCTS THROUGH THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 1017 PM CDT FRI MAY 15 2015/ DISCUSSION... LIFT ASSOCIATED WITH A SHORTWAVE TROF LIFTING THROUGH EASTERN TX ALONG WITH A DEEP MSTR POOL PER KLIX 00Z RAOB HELPING TO SUSTAIN/GENERATE CONVECTION ACROSS SOUTH CENTRAL/SOUTHEAST LA AND THE ADJACENT COASTAL WATERS. POP/WX/QPF GRIDS WERE ADJUSTED IN THE SHORT TERM BASED PRIMARILY ON THE HRRR AND RADAR TRENDS...WITH A NOD TO THE FORMER OVERNIGHT WHICH SHOWS ISOLATED TO PERHAPS SCATTERED ACTIVITY CONTINUING EAST OF THE SABINE RIVER. MINOR TWEAKS TO REMAINING GRIDS...WITH A SLIGHT INCREASE IN WIND/WIND GUST GRIDS REQUIRING A SCEC HEADLINE OVER THE GULF WATERS. 13 PREV DISCUSSION... /ISSUED 650 PM CDT FRI MAY 15 2015/ AVIATION...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE OVER CENTRAL LOUISIANA INTO ACADIANA. REMAINDER OF THE AREA IS CLEAR OF ANY PRECIP. MUCH OF THIS ACTIVITY WILL BE DYING OFF IN THE NEXT FEW HOURS WITH COOLING. WILL HOWEVER MAINTAIN VCSH THROUGH THE NIGHT AT LFT AND ARA WITH ACTIVITY NOTED OFFSHORE FROM THESE SITES. OTHERWISE...VFR ONGOING OVER THE AREA AT THIS TIME. EXPECTING ANOTHER ROUND OF MVFR STRATOCU TO DEVELOP AS THE NIGHT PROGRESSES. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO RETURN AREA-WIDE SATURDAY MORNING...TRANSITIONING TO TSRA FOR THE AFTERNOON. PREV DISCUSSION... /ISSUED 325 PM CDT FRI MAY 15 2015/ DISCUSSION...AN UPPER TROUGH REMAINS ACROSS THE WEST HALF OF THE COUNTRY THIS AFTERNOON WITH MULTIPLE SHORT WAVES ROTATING AROUND THE LARGER GYRE. ONE SHORT WAVE IS PUSHING THROUGH THE EAST HALF OF TX WITH A LINE OF STORMS PUSH ACROSS THE CENTRAL TX COAST. FARTHER EAST ACROSS DEEP SE TX AND LA WHERE THE HEATING OF THE DAY HAS COMBINED WITH THE UPPER DIVERGENCE IN PLACE TO DEVELOP SCT TO NUMEROUS SHOWERS AND STORMS AWAY FROM THE COAST. AS SUNSET APPROACHES CONVECTION IS EXPECTED TO DECREASE INCLUDING THE CENTRAL TX COAST QLCS, HOWEVER AREAS OF RAIN MAY MOVE INTO THE WEST HALF OF THE CWA AS THE REMNANTS OF THE LINE OF STORMS DRAWS CLOSER AND ADDITIONAL SCT STORMS MAY REDEVELOP LATER IN THE NIGHT AS THE SHORT WAVE MOVES IN. A SIMILAR SITUATION IS EXPECTED FOR SAT AND SUN AS CONVECTION WILL REDEVELOP EACH AFTERNOON AND GRADUALLY DECREASE THROUGH THE LATE AFTERNOON AND EARLY EVENING. A SLIGHT INCREASE IN COVERAGE IS EXPECTED MONDAY AND TUESDAY AS THE LARGER WESTERN TROUGH AXIS MOVES ACROSS THE REGION. FROM MID WEEK ON MORE TYPICAL EARLY SUMMER WEATHER IS EXPECTED WITH ISOLATED TO WIDELY SCT AFTERNOON STORMS OCCUR UNDER WEAK RIDGING. && .PRELIMINARY POINT TEMPS/POPS... AEX 70 85 72 87 / 20 60 30 50 LCH 74 85 75 86 / 30 40 20 40 LFT 72 86 74 87 / 40 50 30 40 BPT 75 86 75 86 / 20 30 20 40 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT EXERCISE CAUTION UNTIL 6 AM CDT SATURDAY FOR GMZ450- 452-455-470-472-475. && $$ AVIATION...23
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1140 PM EDT SUN MAY 17 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 326 PM EDT SUN MAY 17 2015 A STRONG STORM FOR THIS TIME OF YEAR WILL TRACK TOWARD WESTERN LAKE SUPERIOR BY MONDAY MORNING AND THEN INTO CENTRAL ONTARIO BY TUESDAY MORNING. THAT WILL CAUSE A STRONG COLD FRONT TO COME THROUGH THIS AREA MONDAY AFTERNOON. SCATTERED SHOWER AND THUNDERSTORMS ARE EXPECTED EARLY TONIGHT WELL AHEAD OF THE COLD FRONT. THEN IT WILL TURN BREEZY AND MUCH COLDER MONDAY NIGHT AND TUESDAY. HIGHS WILLS STRUGGLE TO MAKE 50 TUESDAY AND THERE COULD BE A FROST AND FREEZING TEMPERATURES BY WEDNESDAY MORNING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 326 PM EDT SUN MAY 17 2015 I CONTINUE TO BELIEVE THE RISK FOR STRONG TO SEVERE STORMS IS RATHER LIMITED TONIGHT. THE BEST DYNAMICS ARE TO OUR WEST AND NORTH...CLOSER TO THE SYSTEM OVER MINNESOTA AND WISCONSIN. THE LATEST RUN OF THE RAP MODEL (18Z) CONTINUES TO SHOW THE LOW LEVEL JET CORE TRACKING THROUGH WESTERN WISCONSIN THIS EVENING LEAVING SOUTHWEST MICHIGAN IN THE SPEED AREA BEHIND THAT JET. ALSO THE BEST UPPER DIVERGENCE ASSOCIATED WITH THE POLAR JET CORE IS EASILY OVER WISCONSIN. WHILE THERE IS A SIGNIFICANT AMOUNT OF MIXED LAYER CAPE THIS EVENING THE LACK OF DYNAMICS WILL RESULT IN THE BEST STORMS STAYING OVER WISCONSIN. EVEN SO SOME SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH OUR EASTERN CWA LATE THIS AFTERNOON THEN ANOTHER AREA WILL TRACK THROUGH OUR CENTRAL AND EASTER COUNTIES AFTER 8PM BUT I DO NOT EXPECT ANY SEVERE STORMS AT THIS TIME. DRY AIR MOVES IN MONDAY THEN MUCH COLDER AIR MOVES IN BEHIND THE SYSTEM FOR MONDAY NIGHT INTO TUESDAY NIGHT. THERE IS NOT ENOUGH MOISTURE FOR SHOWERS IN THE COLD AIR MONDAY NIGHT OR TUESDAY. WE MAY WILL HAVE FREEZING TEMPERATURES AND WIDESPREAD FROST TUESDAY NIGHT AS SKIES CLEAR. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 326 PM EDT SUN MAY 17 2015 MUCH OF THE EXTENDED PERIOD WILL BE COOL AND DRY...BUT WE SHOULD SEE A WARM UP BY THE WEEKEND...ALONG WITH A CHANCE OF SHOWERS AND STORMS RETURNING SATURDAY NIGHT AND SUNDAY. AN UPPER LOW OVER JAMES BAY WILL KEEP US COOL WITH A NORTHWEST UPPER FLOW. H8 TEMPS WED THROUGH FRI REMAIN IN THE +1 TO +4C RANGE... KEEPING DAYTIME HIGH TEMPS BELOW NORMAL...MAINLY IN THE LOW AND MID 60S. THERE SHOULD BE A BACK DOOR COLD FRONT COME THROUGH THURSDAY NIGHT...BUT IT APPEARS DRY...JUST SUPPLYING A EXTRA SHOT OF COOL AIR INTO FRIDAY. A WARM UP SHOULD COMMENCE SATURDAY AS AN UPPER RIDGE BEGINS TO BUBBLE TOWARD THE AREA PUSHING THE NW FLOW EAST. TEMPS SHOULD RETURN TO NEAR NORMAL VALUES. RAIN CHANCES WILL RETURN SATURDAY NIGHT OR SUNDAY AS A WARM FRONT LIFTS NORTH ACROSS IN/OH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1134 PM EDT SUN MAY 17 2015 OVERALL THE SHOWERS AND THUNDERSTORMS HAVE BEEN DIMINISHING THIS EVENING. WILL KEEP ONLY VCSH GOING FOR A FEW SITES TONIGHT. FOG AND SOME STRATUS COULD DEVELOP. THIS WILL NEED TO BE MONITORED AS AN ELEVATED RISK FOR IFR EXITS. ANY FOG SHOULD DISSIPATE BY MID MORNING MONDAY. I DID ADD VCTS TO KJXN FOR MON AFTN. THE ATMOSPHERE DESTABILIZES DURING THE DAY. AS A FRONT PUSHES IN THERE COULD BE A FEW STORMS DEVELOPING ROUGHLY MID AFTERNOON INTO THE LATE AFTERNOON HOURS. WINDS WILL VEER AND INCREASE THROUGH MON AFTERNOON AS A COOLER AND DRIER AIRMASS FLOWS IN. && .MARINE... ISSUED AT 326 PM EDT SUN MAY 17 2015 I CONTINUED THE FOG ADVISORY AS WEB CAMS DO SHOW SOME FOG YET. WE WILL LIKELY NEED A SMALL CRAFT ADVISORY MONDAY NIGHT AND TUESDAY AS THE COLD AIR COMES IN. && .HYDROLOGY... ISSUED AT 1210 AM EDT SUN MAY 17 2015 THE MAIN THREAT THROUGH THE NEXT 24 HOURS WILL BE THE POSSIBILITY FOR LOCALIZED HEAVY RAINFALL. A MAJORITY OF THE AREA STREAMS AND RIVERS ARE RUNNING WELL BELOW ADVISORY LEVELS WITH A COUPLE OF SITES SLIGHTLY BELOW. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AND TRAVEL EAST OUT OF THE UPPER MIDWEST THIS EVENING AND INTO TONIGHT. AREA AVERAGE RAINFALL MAY RUN FROM A FEW TENTHS OF AN INCH UPWARDS OF A HALF INCH. LOCALIZED HEAVY POCKETS WILL CREATE GREAT VARIATIONS IN RAINFALL TOTALS IN SHORT DISTANCES. LOCATIONS THAT ARE AFFECTED BY HEAVIER RAINFALL MAY EXPERIENCE LOCALIZED PONDING OR TEMPORARY STREET FLOODING WITH SMALL CREEK AND STREAM FLUCTUATIONS POSSIBLE. LARGER RIVERS ARE EXPECTED TO REMAIN BELOW ACTION STAGE THROUGH THE PERIOD AS FEEDBACK TIMES WILL TAKE US INTO DRIER WEATHER FOR THE UPCOMING WEEK. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...WDM SHORT TERM...WDM LONG TERM...JK AVIATION...MJS HYDROLOGY...JAM MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
739 PM EDT SUN MAY 17 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 326 PM EDT SUN MAY 17 2015 A STRONG STORM FOR THIS TIME OF YEAR WILL TRACK TOWARD WESTERN LAKE SUPERIOR BY MONDAY MORNING AND THEN INTO CENTRAL ONTARIO BY TUESDAY MORNING. THAT WILL CAUSE A STRONG COLD FRONT TO COME THROUGH THIS AREA MONDAY AFTERNOON. SCATTERED SHOWER AND THUNDERSTORMS ARE EXPECTED EARLY TONIGHT WELL AHEAD OF THE COLD FRONT. THEN IT WILL TURN BREEZY AND MUCH COLDER MONDAY NIGHT AND TUESDAY. HIGHS WILLS STRUGGLE TO MAKE 50 TUESDAY AND THERE COULD BE A FROST AND FREEZING TEMPERATURES BY WEDNESDAY MORNING. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 326 PM EDT SUN MAY 17 2015 I CONTINUE TO BELIEVE THE RISK FOR STRONG TO SEVERE STORMS IS RATHER LIMITED TONIGHT. THE BEST DYNAMICS ARE TO OUR WEST AND NORTH...CLOSER TO THE SYSTEM OVER MINNESOTA AND WISCONSIN. THE LATEST RUN OF THE RAP MODEL (18Z) CONTINUES TO SHOW THE LOW LEVEL JET CORE TRACKING THROUGH WESTERN WISCONSIN THIS EVENING LEAVING SOUTHWEST MICHIGAN IN THE SPEED AREA BEHIND THAT JET. ALSO THE BEST UPPER DIVERGENCE ASSOCIATED WITH THE POLAR JET CORE IS EASILY OVER WISCONSIN. WHILE THERE IS A SIGNIFICANT AMOUNT OF MIXED LAYER CAPE THIS EVENING THE LACK OF DYNAMICS WILL RESULT IN THE BEST STORMS STAYING OVER WISCONSIN. EVEN SO SOME SHOWERS AND THUNDERSTORMS WILL TRACK THROUGH OUR EASTERN CWA LATE THIS AFTERNOON THEN ANOTHER AREA WILL TRACK THROUGH OUR CENTRAL AND EASTER COUNTIES AFTER 8PM BUT I DO NOT EXPECT ANY SEVERE STORMS AT THIS TIME. DRY AIR MOVES IN MONDAY THEN MUCH COLDER AIR MOVES IN BEHIND THE SYSTEM FOR MONDAY NIGHT INTO TUESDAY NIGHT. THERE IS NOT ENOUGH MOISTURE FOR SHOWERS IN THE COLD AIR MONDAY NIGHT OR TUESDAY. WE MAY WILL HAVE FREEZING TEMPERATURES AND WIDESPREAD FROST TUESDAY NIGHT AS SKIES CLEAR. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 326 PM EDT SUN MAY 17 2015 MUCH OF THE EXTENDED PERIOD WILL BE COOL AND DRY...BUT WE SHOULD SEE A WARM UP BY THE WEEKEND...ALONG WITH A CHANCE OF SHOWERS AND STORMS RETURNING SATURDAY NIGHT AND SUNDAY. AN UPPER LOW OVER JAMES BAY WILL KEEP US COOL WITH A NORTHWEST UPPER FLOW. H8 TEMPS WED THROUGH FRI REMAIN IN THE +1 TO +4C RANGE... KEEPING DAYTIME HIGH TEMPS BELOW NORMAL...MAINLY IN THE LOW AND MID 60S. THERE SHOULD BE A BACK DOOR COLD FRONT COME THROUGH THURSDAY NIGHT...BUT IT APPEARS DRY...JUST SUPPLYING A EXTRA SHOT OF COOL AIR INTO FRIDAY. A WARM UP SHOULD COMMENCE SATURDAY AS AN UPPER RIDGE BEGINS TO BUBBLE TOWARD THE AREA PUSHING THE NW FLOW EAST. TEMPS SHOULD RETURN TO NEAR NORMAL VALUES. RAIN CHANCES WILL RETURN SATURDAY NIGHT OR SUNDAY AS A WARM FRONT LIFTS NORTH ACROSS IN/OH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 732 PM EDT SUN MAY 17 2015 SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE INTO TONIGHT. CELLS WERE DEVELOPING AT THIS TIME...ESPECIALLY AROUND KJXN AND SW OF KAZO. BASED ON THE INSTABILITY IN THE AIRMASS...WILL FEATURE THE HIGHEST PROBABILITY OF STORMS FOR KAZO...KBTL...KJXN AND KLAN. WILL NEED TO MONITOR TRENDS IN THE DEVELOPING CELLS FOR KGRR AND KMKG. ONE BIGGER CHANGE TO THE FORECAST WAS TO FEATURE IFR FOR KMKG. AS THE MOIST AIRMASS ADVECTS OVER THE COLDER WATERS OF LAKE MI...WE SHOULD SEE SOME LOWER CLOUDS/FOG MOVE IN FOR KMKG MAINLY AFTER MIDNIGHT. AN AFTERNOON STORM LOOKS POSSIBLE INLAND TOWARD KLAN AND KJXN ON MONDAY...HOWEVER THE COVERAGE LOOKS TOO LIMITED TO INCLUDE IN THE FORECAST AT THIS TIME. WILL MONITOR TRENDS CLOSELY ON THIS POTENTIAL. && .MARINE... ISSUED AT 326 PM EDT SUN MAY 17 2015 I CONTINUED THE FOG ADVISORY AS WEB CAMS DO SHOW SOME FOG YET. WE WILL LIKELY NEED A SMALL CRAFT ADVISORY MONDAY NIGHT AND TUESDAY AS THE COLD AIR COMES IN. && .HYDROLOGY... ISSUED AT 1210 AM EDT SUN MAY 17 2015 THE MAIN THREAT THROUGH THE NEXT 24 HOURS WILL BE THE POSSIBILITY FOR LOCALIZED HEAVY RAINFALL. A MAJORITY OF THE AREA STREAMS AND RIVERS ARE RUNNING WELL BELOW ADVISORY LEVELS WITH A COUPLE OF SITES SLIGHTLY BELOW. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AND TRAVEL EAST OUT OF THE UPPER MIDWEST THIS EVENING AND INTO TONIGHT. AREA AVERAGE RAINFALL MAY RUN FROM A FEW TENTHS OF AN INCH UPWARDS OF A HALF INCH. LOCALIZED HEAVY POCKETS WILL CREATE GREAT VARIATIONS IN RAINFALL TOTALS IN SHORT DISTANCES. LOCATIONS THAT ARE AFFECTED BY HEAVIER RAINFALL MAY EXPERIENCE LOCALIZED PONDING OR TEMPORARY STREET FLOODING WITH SMALL CREEK AND STREAM FLUCTUATIONS POSSIBLE. LARGER RIVERS ARE EXPECTED TO REMAIN BELOW ACTION STAGE THROUGH THE PERIOD AS FEEDBACK TIMES WILL TAKE US INTO DRIER WEATHER FOR THE UPCOMING WEEK. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...DENSE FOG ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849. && $$ SYNOPSIS...WDM SHORT TERM...WDM LONG TERM...JK AVIATION...MJS HYDROLOGY...JAM MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
121 PM EDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT SAT MAY 16 2015 WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH PLAINS OF S DAKOTA TO NEB. BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY. MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER 100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH EDGE OF H85-H7 MOISTURE TRANSPORT. EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF FOG...LOCALLY DENSE. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 520 AM EDT SAT MAY 16 2015 SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50 KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5 INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400- 800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY WITH PERHAPS A FEW LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE MICHIGAN SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH COOLER (AROUND 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY BE DRY OVERNIGHT. MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD -SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W- NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST. MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN. DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED THRU FRI...BUT REMAIN BLO NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 121 PM EDT SAT MAY 16 2015 TOUGH FORECAST TO FIGURE OUT WITH CONFIDENCE FAIRLY LOW. VFR CONDITIONS WILL CONTINUE INTO THIS EVENING. UPSLOPE STRATUS AND FOG COULD AFFECT BOTH CMX AND SAW TONIGHT WITH CMX GETTING IT FROM LAKE SUPERIOR AND SAW GETTING IT WITH SOUTHEAST FLOW FROM LAKE MICHIGAN. TOUGH TO TELL HOW LOW THE VISIBILITIES WILL GO AND WHAT HEIGHT IT WILL BE...BUT WENT AHEAD AND WENT MVFR CONDITIONS FOR BOTH SITES ANYWAY. IWD COULD GET THE SAME THING AND WENT MVFR CONDITIONS LATE TONIGHT. THINK CMX WILL BE ABLE TO MIX OUT FOR SUN MORNING AND WENT VFR FOR THEM. IWD AND SAW WILL HAVE A HARDER TIME MIXING OUT AND KEPT THE LOW CLOUDS IN LONGER. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT SAT MAY 16 2015 WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250. && $$ SHORT TERM...JLA LONG TERM...VOSS AVIATION...07 MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT SAT MAY 16 2015 WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH PLAINS OF S DAKOTA TO NEB. BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY. MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER 100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH EDGE OF H85-H7 MOISTURE TRANSPORT. EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF FOG...LOCALLY DENSE. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 520 AM EDT SAT MAY 16 2015 SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50 KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5 INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400- 800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY WITH PERHAPS A FEW LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE MICHIGAN SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH COOLER (AROUND 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY BE DRY OVERNIGHT. MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD -SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W- NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST. MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN. DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED THRU FRI...BUT REMAIN BLO NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 728 AM EDT SAT MAY 16 2015 THICKER CLOUDS IN MID-LEVELS EARLY THIS MORNING HAVE PROHIBITED WIDESPREAD FOG FROM FORMING. SHALLOW GROUND FOG EARLY AT KIWD BUT OTHERWISE EXPECT MINIMAL FOG ISSUES REST OF THE DAY AND INTO TONIGHT. SCT-BKN VFR CLOUDS WILL CONTINUE AT ALL THE TAF SITES INTO TONIGHT. MIGHT SEE AN ISOLD SHRA OR TSRA LATE TONIGHT...BUT COVERAGE AND PROBABILITY IS TOO LOW TO INCLUDE FOR THESE TAFS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT SAT MAY 16 2015 WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250. && $$ SHORT TERM...JLA LONG TERM...VOSS AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT SAT MAY 16 2015 WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH PLAINS OF S DAKOTA TO NEB. BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY. MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER 100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH EDGE OF H85-H7 MOISTURE TRANSPORT. EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF FOG...LOCALLY DENSE. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 520 AM EDT SAT MAY 16 2015 SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50 KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5 INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400- 800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY WITH PERHAPS A FEW LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE MICHIGAN SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH COOLER (AROUND 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY BE DRY OVERNIGHT. MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD -SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W- NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST. MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN. DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED THRU FRI...BUT REMAIN BLO NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 142 AM EDT SAT MAY 16 2015 LIGHT WINDS AND ANTECEDENT MOISTURE CONTINUE TO MAKE THE FORECAST A CHALLENGE THIS MORNING. THERE CONTINUES TO BE A POTENTIAL FOR LOW CIGS AND FOG AT ALL THREE SITES. HOWEVER ONLY KSAW AT IFR CIGS AT THIS TIME WHILE KCMX AND KIWD ARE MVFR. CONCERN IS 0Z NAM BUFKIT SUPPORTS LOW CLOUDS/FOG AT ALL THREE SITES...HOWEVER THE NAM HAS BEEN NOTED AS BEING A BIT AGGRESSIVE WITH LOW LEVEL MOISTURE. AT THIS TIME...STILL EXPECT IFR CONDITIONS AT KCMX AND KSAW FOR A TIME OVERNIGHT BUT DO NOT EXPECT RESTRICTIONS TO BE AS SIGNIFICANT AS SUGGESTED BY THE NAM. FORTUNATELY...LOW CLOUDS AND FOG WILL LIFT AFTER SUNRISE WITH VFR CONDITIONS PREVAILING BY 15Z AT THE LATEST AT KCMX AND KSAW. THERE IS A SLIGHT CHANCE OF SHOWERS AND PERHAPS A THUNDERSTORMS MOVING INTO THE KIWD AREA CLOSE TO THE END OF THE FORECAST BUT FOR NOW HAVE LEFT THIS OUT OF THE CURRENT DUE TO A HIGH DEGREE OF UNCERTAINTY WITH THE TIMING OF THE ARRIVAL OF THE CONVECTION. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT SAT MAY 16 2015 WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250. && $$ SHORT TERM...JLA LONG TERM...VOSS AVIATION...RJT MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
925 PM CDT SUN MAY 17 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 412 PM CDT SUN MAY 17 2015 THUNDERSTORMS HAVE BECOME FAIRLY WIDESPREAD THIS AFTERNOON TO THE EAST OF A COLD FRONT THAT IS ADVANCING EAST ACROSS MN. THE SFC LOW DRIVING THIS FRONT WAS DOWN TO 995 MB AND SPINNING RATHER AGGRESSIVELY ACROSS NE SODAK. BASED ON SFC PRESSURE FALLS...THIS LOW WILL BE ON ITS WAY OFF TO THE ARROWHEAD TONIGHT. WE HAVE QUITE THE CONTRAST IN AIRMASSES ACROSS THE SYSTEM...WITH SUMMER-LIKE AIR TO ITS EAST WITH TEMPERATURES IN THE 70S AND DEWPS IN THE 60S...WHILE WEST OF THE LOW...TEMPERATURES ARE DOWN IN THE MID 30S ACROSS NODAK. IN FACT...IT IS COLD ENOUGH ON THE WRN EDGE OF THE PRECIP SHIELD THAT WE ARE SEEING A RAIN/SNOW MIX THIS AFTERNOON. FOR THE REST OF TODAY...LIKE THE IDEA THAT THE HRRR HAS BEEN RUNNING WITH ALL DAY THAT MATCHES WELL WITH REALITY NOW. AND THAT IS FOR THE WIDESPREAD DISCRETE CELLS TO CONTINUE THROUGH THE EVENING AHEAD OF THE COLD FRONT. WE HAVE SEEN SBCAPE INCREASE TO BETWEEN 1000 AND 1500 J/KG...BUT WITH LITTLE CIN IN PLACE...WE ARE BASICALLY POPPING CONVECTION AS SOON AS INSTABILITY DEVELOPS. MID-LEVEL LAPSE RATES ARE PRETTY WEAK THOUGH...WHICH IS A BIG LIMITING FACTOR IN THE SVR. STILL...FREEZING LEVELS HAVE DROPPED FROM ALMOST 12K FT AGL YESTERDAY TO BETWEEN 8K AND 9K FEET TODAY...WHICH WILL CONTINUE TO ALLOW FOR THE THREAT FOR MARGINALLY SVR HAIL THROUGH THE EVENING. GIVEN THE DEPTH OF THE SYSTEM IN TO OUR NW...WE ARE SEEING LOTS OF WIND THROUGH PRETTY MUCH THE WHOLE DEPTH OF THE ATMO...SO THESE SHOWERS WILL LIKELY BE ABLE TO MIX SOME OF THAT DOWN...LEADING TO SOME GUSTY WINDS AS WELL. TORNADO THREAT DOES NOT LOOK AS GOOD AS YESTERDAY...WHEN WE HAD A WARM FRONT DRAPED ACROSS THE STATE...BUT THE RAP HAS BEEN SHOWING 0-1 SHEAR INCREASING LATE THIS AFTERNOON ACROSS ERN MN/WRN WI...WHERE THE BEST CHANCE FOR SEEING A BRIEF TORNADO WOULD EXIST. FOR TONIGHT...THE BIG THING WE WILL SEE IS STRONG CAA AS THE LOW PUSHES TOWARD THE ARROWHEAD. THIS WILL LEAD TO SOME AGGRESSIVE TEMPERATURE DROPS OVERNIGHT...WHERE LOWS IN WRN MN WILL FALL BACK INTO THE MID 30S...OR ABOUT 35 DEGREES COLDER THAN THE HIGHS WERE THIS AFTERNOON. IN ADDITION TO THE COLD AIR...WE WILL SEE WRAP AROUND PRECIP DIP DOWN ABOUT AS FAR SOUTH AS A MADISON TO MILLE LACS LAKE LINE. FORECAST SOUNDINGS IN THIS AREA ARE ALSO COLD ENOUGH TO SHOW A RAIN/SLEET MIX DEVELOPING LATE TONIGHT. IN FACT...THE NAM WOULD SAY THE P-TYPE AT AXN WILL BE ALL SLEET TOMORROW MORNING...SO DID INTRODUCE A PRECIP MIX INTO THE GRIDS. BESIDE THE PRECIP...WINDS WILL BE STRONG AS WELL. TOP OF THE CHANNEL MIX DOWN AT MOST SITES IN MN IS OVER 40 KTS. WE ARE RIGHT ON THE CUSP OF NEEDING A WIND ADVY...BUT DECIDED TO HOLD OFF ON ONE FOR NOW AND WILL LET THE SEVERE POTENTIAL PLAY OUT BEFORE HOISTING A WIND ADVY. FOR MONDAY...THERE IS NO WAY AROUND IT...IT WILL BE A RAW DAY. NAM HAS H85 TEMPS DROPPING TO BETWEEN -5 AND -8C...WHICH IS BELOW THE CLIMATOLOGICAL RECORD FOR H85 TEMPS FOR THE DAY AT STC/MPX. THROW IN THE MOSTLY CLOUDY SKIES...AND HAVE HIGH CONFIDENCE IN HIGHS STAYING IN THE 40S...WITH HIGHS ONLY IN THE 30S OUT TOWARD AXN. THESE VALUES WILL BE IN THE 25 TO 35 DEGREES BELOW NORMAL RANGE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 412 PM CDT SUN MAY 17 2015 THE AFOREMENTIONED STRONG COLD ADVECTION ON MONDAY WILL KEEP THE LOCAL AREA COOL ON TUESDAY AS WELL WITH HIGHS LIKELY REMAINING IN THE 50S. THE TROUGH MOVES EAST BY WEDNESDAY AND EAST COAST TROUGH SHEARS OUT BEFORE ADVANCING OUT OF THE ROCKIES. THEREFORE WE SHOULD SEE DRY WEATHER AND COOL TO MILD TEMPERATURES THROUGH THE WEEK...WITH A SLOW WARMING TREND TIME. WE EXPECT TUESDAY AND WEDNESDAY MORNINGS TO FALL INTO THE 30S ACROSS CENTRAL MN AND WEST CENTRAL WI...SO WE COULD SEE A LITTLE FROST IF WE MANAGE TO GET CLEARING AND THE WINDS STAY CALM. WEDNESDAY MORNING HAS A BETTER CHANCE OF A CALM WIND AND AT LEAST PARTIAL CLEARING. THE NEXT CHANCE FOR THUNDERSTORMS WILL LIKELY HOLD OFF UNTIL THE WEEKEND WHEN ANOTHER TROUGH APPROACHES THE REGION FROM THE PLAINS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 925 PM CDT SUN MAY 17 2015 SCATTERED SHOWERS WILL CONTINUE IN EASTERN MN THROUGH BY 03Z AND ABOUT 04-05Z IN WESTERN WI. THERE WILL BE SEVERAL HOURS OF VFR IN MN /LONGER IN WI/ BEFORE AN MVFR STRATUS DECK MOVES IN LATE THIS EVENING AND TONIGHT AND LINGERS THROUGH THE DAY TOMORROW. IFR IS POSSIBLE ACROSS PORTIONS OF CENTRAL MN...BUT MOST OF THE TAF SITES SHOULD REMAIN BETWEEN 1500-2500FT FOR CLOUD BASES. STRONG WINDS RIGHT ALONG OR BEHIND THE SHOWERS LOOK TO CONTINUE THIS EVENING WITH GUSTS BETWEEN 40-50MPH BEING OBSERVED AT MANY SITES. KMSP... SHOWERS HAVE ENDED...BUT THE BIG CONCERN IS NOW THE STRONG SW WINDS AND CROSSWIND COMPONENT THAT HAS CAUGHT US A LITTLE OFF GAURD. WE THIN THE STRONGEST WINDS WILL SUBSIDE BY 03Z...BACK UNDER 35KTS...BUT THE DIRECTION MAY TAKE ANOTHER 1-2 HOURS /05Z/ TO BACK MORE TO THE WEST TONIGHT. OTHERWISE...WE HAVE MEDIUM TO HIGH CONFIDENCE OF 2000-2200FT CEILINGS AT THE AIRPORT BEFORE THE MONDAY MORNING COMMUTE...BUT WE ARE NOT TOO CONFIDENT THEY WILL BE BELOW 1700FT. WE SHOULD HAVE A MUCH BETTER IDEA AT THE 06Z AND 09Z UPDATES. /OUTLOOK FOR KMSP/ TUE...MVFR CIGS POSSIBLE EARLY. WINDS N AT 10 KTS. WED...VFR. WINDS N 5 KTS. THU...VFR. WINDS NNW 5 TO 10 KTS. FRI...VFR. WINDS VARIABLE 0 TO 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 4 AM CDT MONDAY FOR MNZ047-054>056-064-065- 073-074-082-091. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...CLF AVIATION...CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
700 PM CDT SUN MAY 17 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 412 PM CDT SUN MAY 17 2015 THUNDERSTORMS HAVE BECOME FAIRLY WIDESPREAD THIS AFTERNOON TO THE EAST OF A COLD FRONT THAT IS ADVANCING EAST ACROSS MN. THE SFC LOW DRIVING THIS FRONT WAS DOWN TO 995 MB AND SPINNING RATHER AGGRESSIVELY ACROSS NE SODAK. BASED ON SFC PRESSURE FALLS...THIS LOW WILL BE ON ITS WAY OFF TO THE ARROWHEAD TONIGHT. WE HAVE QUITE THE CONTRAST IN AIRMASSES ACROSS THE SYSTEM...WITH SUMMER-LIKE AIR TO ITS EAST WITH TEMPERATURES IN THE 70S AND DEWPS IN THE 60S...WHILE WEST OF THE LOW...TEMPERATURES ARE DOWN IN THE MID 30S ACROSS NODAK. IN FACT...IT IS COLD ENOUGH ON THE WRN EDGE OF THE PRECIP SHIELD THAT WE ARE SEEING A RAIN/SNOW MIX THIS AFTERNOON. FOR THE REST OF TODAY...LIKE THE IDEA THAT THE HRRR HAS BEEN RUNNING WITH ALL DAY THAT MATCHES WELL WITH REALITY NOW. AND THAT IS FOR THE WIDESPREAD DISCRETE CELLS TO CONTINUE THROUGH THE EVENING AHEAD OF THE COLD FRONT. WE HAVE SEEN SBCAPE INCREASE TO BETWEEN 1000 AND 1500 J/KG...BUT WITH LITTLE CIN IN PLACE...WE ARE BASICALLY POPPING CONVECTION AS SOON AS INSTABILITY DEVELOPS. MID-LEVEL LAPSE RATES ARE PRETTY WEAK THOUGH...WHICH IS A BIG LIMITING FACTOR IN THE SVR. STILL...FREEZING LEVELS HAVE DROPPED FROM ALMOST 12K FT AGL YESTERDAY TO BETWEEN 8K AND 9K FEET TODAY...WHICH WILL CONTINUE TO ALLOW FOR THE THREAT FOR MARGINALLY SVR HAIL THROUGH THE EVENING. GIVEN THE DEPTH OF THE SYSTEM IN TO OUR NW...WE ARE SEEING LOTS OF WIND THROUGH PRETTY MUCH THE WHOLE DEPTH OF THE ATMO...SO THESE SHOWERS WILL LIKELY BE ABLE TO MIX SOME OF THAT DOWN...LEADING TO SOME GUSTY WINDS AS WELL. TORNADO THREAT DOES NOT LOOK AS GOOD AS YESTERDAY...WHEN WE HAD A WARM FRONT DRAPED ACROSS THE STATE...BUT THE RAP HAS BEEN SHOWING 0-1 SHEAR INCREASING LATE THIS AFTERNOON ACROSS ERN MN/WRN WI...WHERE THE BEST CHANCE FOR SEEING A BRIEF TORNADO WOULD EXIST. FOR TONIGHT...THE BIG THING WE WILL SEE IS STRONG CAA AS THE LOW PUSHES TOWARD THE ARROWHEAD. THIS WILL LEAD TO SOME AGGRESSIVE TEMPERATURE DROPS OVERNIGHT...WHERE LOWS IN WRN MN WILL FALL BACK INTO THE MID 30S...OR ABOUT 35 DEGREES COLDER THAN THE HIGHS WERE THIS AFTERNOON. IN ADDITION TO THE COLD AIR...WE WILL SEE WRAP AROUND PRECIP DIP DOWN ABOUT AS FAR SOUTH AS A MADISON TO MILLE LACS LAKE LINE. FORECAST SOUNDINGS IN THIS AREA ARE ALSO COLD ENOUGH TO SHOW A RAIN/SLEET MIX DEVELOPING LATE TONIGHT. IN FACT...THE NAM WOULD SAY THE P-TYPE AT AXN WILL BE ALL SLEET TOMORROW MORNING...SO DID INTRODUCE A PRECIP MIX INTO THE GRIDS. BESIDE THE PRECIP...WINDS WILL BE STRONG AS WELL. TOP OF THE CHANNEL MIX DOWN AT MOST SITES IN MN IS OVER 40 KTS. WE ARE RIGHT ON THE CUSP OF NEEDING A WIND ADVY...BUT DECIDED TO HOLD OFF ON ONE FOR NOW AND WILL LET THE SEVERE POTENTIAL PLAY OUT BEFORE HOISTING A WIND ADVY. FOR MONDAY...THERE IS NO WAY AROUND IT...IT WILL BE A RAW DAY. NAM HAS H85 TEMPS DROPPING TO BETWEEN -5 AND -8C...WHICH IS BELOW THE CLIMATOLOGICAL RECORD FOR H85 TEMPS FOR THE DAY AT STC/MPX. THROW IN THE MOSTLY CLOUDY SKIES...AND HAVE HIGH CONFIDENCE IN HIGHS STAYING IN THE 40S...WITH HIGHS ONLY IN THE 30S OUT TOWARD AXN. THESE VALUES WILL BE IN THE 25 TO 35 DEGREES BELOW NORMAL RANGE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 412 PM CDT SUN MAY 17 2015 THE AFOREMENTIONED STRONG COLD ADVECTION ON MONDAY WILL KEEP THE LOCAL AREA COOL ON TUESDAY AS WELL WITH HIGHS LIKELY REMAINING IN THE 50S. THE TROUGH MOVES EAST BY WEDNESDAY AND EAST COAST TROUGH SHEARS OUT BEFORE ADVANCING OUT OF THE ROCKIES. THEREFORE WE SHOULD SEE DRY WEATHER AND COOL TO MILD TEMPERATURES THROUGH THE WEEK...WITH A SLOW WARMING TREND TIME. WE EXPECT TUESDAY AND WEDNESDAY MORNINGS TO FALL INTO THE 30S ACROSS CENTRAL MN AND WEST CENTRAL WI...SO WE COULD SEE A LITTLE FROST IF WE MANAGE TO GET CLEARING AND THE WINDS STAY CALM. WEDNESDAY MORNING HAS A BETTER CHANCE OF A CALM WIND AND AT LEAST PARTIAL CLEARING. THE NEXT CHANCE FOR THUNDERSTORMS WILL LIKELY HOLD OFF UNTIL THE WEEKEND WHEN ANOTHER TROUGH APPROACHES THE REGION FROM THE PLAINS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 700 PM CDT SUN MAY 17 2015 SCATTERED SHOWERS AND WEAK THUNDERSTORMS WILL CONTINUE IN EASTERN MN THROUGH ABOUT 01-02Z AND ABOUT 04Z IN WESTERN WI. THERE WILL BE SEVERAL HOURS OF VFR IN MN /LONGER IN WI/ BEFORE AN MVFR STRATUS DECK MOVES IN LATE THIS EVENING AND TONIGHT AND LINGERS THROUGH THE DAY TOMORROW. IFR IS POSSIBLE ACROSS PORTIONS OF CENTRAL MN...BUT MOST OF THE TAF SITES SHOULD REMAIN BETWEEN 1500-2500FT FOR CLOUD BASES. KMSP... THERE ARE A FEW SHOWERS TO THE WEST OF KMSP...WHICH WILL BE IN THE VICINITY FOR THE NEXT 1-2 HOURS BEFORE THE DRIER AIR TAKES OVER AND SHUTS DOWN THE PRECIP CHANCES. OTHERWISE...WE HAVE MEDIUM TO HIGH CONFIDENCE OF 2000-2200FT CEILINGS AT THE AIRPORT BEFORE THE MONDAY MORNING COMMUTE...BUT WE ARE NOT TOO CONFIDENT THEY WILL BE BELOW 1700FT. WE SHOULD HAVE A MUCH BETTER IDEA AT THE 06Z AND 09Z UPDATES. /OUTLOOK FOR KMSP/ TUE...MVFR CIGS POSSIBLE EARLY. WINDS N AT 10 KTS. WED...VFR. WINDS N 5 KTS. THU...VFR. WINDS NNW 5 TO 10 KTS. FRI...VFR. WINDS VARIABLE 0 TO 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 4 AM CDT MONDAY FOR MNZ047-054>056-064-065- 073-074-082-091. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...CLF AVIATION...CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
357 PM CDT SAT MAY 16 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 351 PM CDT SAT MAY 16 2015 WATER VAPOR IMAGERY THIS AFTERNOON INDICATES A STRONG UPPER LEVEL CIRCULATION PUSHING EAST THROUGH NORTHERN NEW MEXICO...WITH CONVECTIVE INITIATION IMMEDIATELY DOWNSTREAM OF THE WAVE ACROSS THE TEXAS PANHANDLE. MEANWHILE...A WARM FRONT HAS LIFTED INTO SOUTHERN MN AND DEW POINTS HAVE RISEN WELL INTO THE 60S. ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS WESTERN MN INTO EASTERN SD WILL CONTINUE AS DESTABILIZATION HAS OCCURRED. A SUBTLE WAVE ADVANCING NORTH WILL HELP INITIATE STORM DEVELOPMENT IN THIS AREA. EFFECTIVE BULK SHEAR VALUES OF AROUND 30-40 KNOTS MAY PRODUCE MULTICELL CLUSTERS WITH ISOLATED EMBEDDED SUPERCELLS CAPABLE OF PRODUCING ISOLATED SEVERE WEATHER ACROSS WESTERN MN THIS EVENING. EASTERN MN AND WESTERN WI SHOULD GENERALLY REMAIN DRY THROUGH THE EVENING...BEFORE SCATTERED SHOWERS AND WEAK THUNDERSTORMS MOVE IN LATE TONIGHT THROUGH SUNDAY MORNING. ON SUNDAY...THE AFOREMENTIONED UPPER LEVEL SHORTWAVE WILL ADVANCE NORTH AND A DEEPENING SURFACE LOW WILL ADVANCE FROM KANSAS NORTHWARD THROUGH NEBRASKA AND EVENTUALLY INTO EASTERN SOUTH DAKOTA. WITH A MOIST AND UNSTABLE AIRMASS PRESENT...MUCH BETTER SHEAR AND SURFACE ENERGY WILL COME TOGETHER THROUGH EARLY AFTERNOON...ESPECIALLY ACROSS EASTERN MN AND WESTERN WI...WHERE THE SEVERE WEATHER RISK HAS BEEN UPGRADED TO THE ENHANCED CATEGORY. 0-6KM EFFECTIVE SHEAR APPROACHING 60 KNOTS COMBINED WITH BETTER SURFACE HEATING ACROSS THIS AREA WILL ALLOW SURFACE BASED CAPE VALUES OF 1000-2000 J/KG. CONFIDENCE IS RELATIVELY LOW THOUGH IN THE SEVERE DEVELOPMENT POTENTIAL DUE TO MORNING CONVECTION AND ITS POSSIBLE AFFECT ON DESTABILIZATION BY EARLY AFTERNOON. GIVEN SUFFICIENT HEATING THOUGH...EXPECT BY EARLY AFTERNOON THE POSSIBILITY OF DISCRETE SUPERCELL THUNDERSTORMS INITIATING IN EASTERN MN AND WESTERN WI WHICH WOULD BE CAPABLE OF PRODUCING SEVERE HAIL...WIND...AND A FEW TORNADOES. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 351 PM CDT SAT MAY 16 2015 SFC LOW OVER N-CENTRAL MN WILL HAVE ITS PROGRESS SLOWED AS IT RUNS INTO HIGHER PRES FROM THE N. MEANWHILE...THE DEEP UPR LVL LOW WILL THEN RUN ATOP THE SFC LOW...MAKING FOR A DEEPLY STACKED LOW PRES AREA CENTERED OVER NERN MN COME DAYBREAK MON MRNG. THE BULK OF THE SHWRS/TSTMS WILL BE IN ERN PORTIONS OF THE WFO MPX CWFA BY SUN EVE...PARTICULARLY ANYTHING OF A STRONG/SEVERE NATURE... LEAVING MAINLY RESIDUAL SHOWERS AND ISOLD TSTMS IN THE WAKE OF THE PASSING CDFNT. WHILE THE FRONTAL PRECIP COVERAGE WANES SUN NIGHT INTO MON...THE DEEP COLD LOW MOVING OVER THE REGION MAY BRING ADDITIONAL LIGHT RAIN SHOWERS TO NRN-CENTRAL MN AND NWRN WI DURG THE DAY ON MON. THIS LOW WILL THEN PULL AWAY FROM THE AREA MON NIGHT INTO TUE...BEING REPLACED BY SFC HIGH PRES THAT WILL REMAIN IN PLACE TUE THRU FRI...MAKING FOR A PROLONGED DRY PERIOD FOR THE REGION. HOWEVER...AT THE SAME TIME...THE NW-SE ORIENTATION OF THE SFC HIGH COMBINED WITH A LONGWAVE TROF SETTING UP OVER ERN NOAM WILL ALLOW A PERSISTENT PATH OF MUCH COLDER CANADIAN AIR TO TAKE RESIDENCE OVER THE REGION THRU AT LEAST THE FIRST HALF OF THE WEEK. THIS POTENT SURGE OF CAA WILL DROP TEMPS NEARLY 30 DEGREES FROM SUN INTO MON AS HIGHS ON MON WILL RANGE FROM THE LOWER 40S TO THE LOWER 50S. TEMPERATURES WILL THEN SLOWLY MODERATE THROUGH THE REST OF THE WEEK...WITH HIGHS RETURNING TO THE UPPER 60S BY THE END OF THE WEEK. FROST MAY BE A CONCERN ON MON AND TUE NIGHTS AS LOWS DIP INTO THE LOW/MID 30S ACROSS PARTS OF CENTRAL MN/WI. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1246 PM CDT SAT MAY 16 2015 CURRENT SCENARIO MAKES FOR A MESSY AVIATION FORECAST FOR THE AREA. A SURFACE LOW IS PUSHING INTO WESTERN SOUTH DAKOTA FROM THE WEST...WITH A WARM FRONT EXTENDING EAST AND DEW POINTS IN THE MID 60S SURGING NORTHWARD INTO SOUTHERN MN. DEW POINT DEPRESSIONS WILL REMAIN JUST A COUPLE DEGREES...AND LOW LEVEL LCL`S SHOULD REMAIN IN PLACE. SO...EXPECTING WIDESPREAD MVFR TO HOLD FOR THE MOST PART WITH A FEW PERIODS OF SCATTERING OCCURRING THIS AFTERNOON. LATE THIS AFTERNOON...A LINE OF THUNDERSTORMS IS EXPECTED TO DEVELOP AND PUSH EAST INTO WESTERN MN AND CONTINUE NORTHEAST THROUGH THE EVENING. RWF/STC/AXN MAY ALL BE DIRECTLY IMPACTED BY THIS LINE...BUT MSP MAY BE ON THE SOUTHERN PERIPHERY OF THESE STORMS...WILL BE SOMETHING TO MONITOR. AS THE LOW DEEPENS IN SOUTH DAKOTA TONIGHT AND TOMORROW MORNING...WE`LL REMAIN IN UNSTABLE AIR AND MORE THUNDERSTORM DEVELOPMENT IS EXPECTED TOMORROW MORNING. KMSP...BEST CHANCE FOR THUNDER TONIGHT WILL BE FROM 03Z TO 06Z...HOWEVER THE HRRR INDICATES THE POSSIBILITY THAT THE THUNDERSTORM CLUSTER MOVING THROUGH WESTERN MN THIS AFTERNOON MAY SLIDE JUST NORTH OF MSP...BUT IF IT DOES STILL EXPECT OTHER SPOTTY THUNDERSTORM DEVELOPMENT LATE TONIGHT. FOR TOMORROW AFTERNOON...STRONG THUNDERSTORMS LOOK TO DEVELOP AND MOVE THROUGH FROM ROUGHLY 20-23Z. /OUTLOOK FOR KMSP/ MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS. TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS. WED...VFR. WINDS NNE 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...SPD LONG TERM...JPC/CLF AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
104 PM CDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 406 AM CDT SAT MAY 16 2015 VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE ACROSS THE PLAINS AND INTO THE UPPER MIDWEST. SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 406 AM CDT SAT MAY 16 2015 THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON. THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON SUNDAY AFTERNOON. THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL MN/WI THROUGH MONDAY. BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE 60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS PARTS OF CENTRAL MN/WI. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1246 PM CDT SAT MAY 16 2015 CURRENT SCENARIO MAKES FOR A MESSY AVIATION FORECAST FOR THE AREA. A SURFACE LOW IS PUSHING INTO WESTERN SOUTH DAKOTA FROM THE WEST...WITH A WARM FRONT EXTENDING EAST AND DEW POINTS IN THE MID 60S SURGING NORTHWARD INTO SOUTHERN MN. DEW POINT DEPRESSIONS WILL REMAIN JUST A COUPLE DEGREES...AND LOW LEVEL LCL`S SHOUDL REMAIN IN PLACE. SO...EXPECTING WIDESPREAD MVFR TO HOLD FOR THE MOST PART WITH A FEW PERIODS OF SCATTERING OCCURRING THIS AFTERNOON. LATE THIS AFTERNOON...A LINE OF THUNDERSTORMS IS EXPECTED TO DEVELOP AND PUSH EAST INTO WESTERN MN AND CONTINUE NORTHEAST THROUGH THE EVENING. RWF/STC/AXN MAY ALL BE DRIECTLY IMPACTED BY THIS LINE...BUT MSP MAY BE ONTHE SOUTHERN PERIPHERY OF THESE STORMS...WILL BE SOMETHING TO MONITOR. AS THE LOW DEEPENS IN SOUTH DAKOTA TONIGHT AND TOMORROW MORNING...WE`LL REMAIN IN UNSTABLE AIR AND MORE THUNDERSTORM DEVELOPMENT IS EXPECTED TOMORROW MORNING. KMSP...BEST CHANCE FOR THUNDER TONIGHT WILL BE FROM 03Z TO 06Z...HOWEVER THE HRRR INDICATES THE POSSIBLITY THAT THE THUNDERSTORM CLUSTER MOVING THROUGH WESTERN MN THIS AFTERNOON MAY SLIDE JUST NORTH OF MSP...BUT IF IT DOES STILL EXPECT OTHER SPOTTY THUNDERSTORM DEVELOPMENT LATE TONIGHT. FOR TOMORROW AFTERNOON...STRONG THUNDERSTORMS LOOK TO DEVELOP AND MOVE THROUGH FROM ROUGHLY 20-23Z. /OUTLOOK FOR KMSP/ MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS. TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS. WED...VFR. WINDS NNE 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...LS AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
546 AM CDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 406 AM CDT SAT MAY 16 2015 VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE ACROSS THE PLAINS AND INTO THE UPPER MIDWEST. SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 406 AM CDT SAT MAY 16 2015 THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON. THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON SUNDAY AFTERNOON. THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL MN/WI THROUGH MONDAY. BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE 60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS PARTS OF CENTRAL MN/WI. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 540 AM CDT SAT MAY 16 2015 HIGH CONFIDENCE THAT THE FIRST 6 HRS WILL BE THUNDERSTORM FREE WITH THE EXCEPTION OF KRWF/KAXN WHERE ISOLD STORMS WILL BE POSSIBLE BUT NOT ENOUGH TO WARRANT MORE THAN VCTS. MVFR CIGS WILL SPREAD NORTHWARD ACROSS CENTRAL MN...WITH VFR CONDS ELSEWHERE THRU 15Z. AFT 18Z...CONFIDENCE IS MUCH LOWER ON SHRA/TSRA COVERAGE...ESPECIALLY IN EASTERN MN/WC WI WHERE TSRA/SHRA MAY NOT OCCUR UNTIL LATER THIS EVENING. HIGHER CONFIDENCE THAT WC/SW MN WILL HAVE SHRA/TSRA WITH LOWER VSBYS/CIGS BY THIS EVENING. WINDS WILL INCREASE FROM THE ESE/SE TODAY...WITH SOME GUSTS DURING THE AFTN. KMSP... CONFIDENCE IS HIGH THAT NO TSRA/SHRA WILL OCCUR IN THE FIRST 6 HRS. CONFIDENCE DECREASES BY MID/LATE AFTN BUT CIGS SHOULD REMAIN VFR. BEST CHC OF TSRA WILL OCCUR LATER THIS EVENING/OVERNIGHT. WINDS WILL SHIFT TO THE SE AND INCREASE DURING THE MORNING. /OUTLOOK FOR KMSP/ MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS. TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS. WED...VFR. WINDS NNE 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...LS AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
406 AM CDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 406 AM CDT SAT MAY 16 2015 VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE ACROSS THE PLAINS AND INTO THE UPPER MIDWEST. SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 406 AM CDT SAT MAY 16 2015 THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON. THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON SUNDAY AFTERNOON. THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL MN/WI THROUGH MONDAY. BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE 60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS PARTS OF CENTRAL MN/WI. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1105 PM CDT FRI MAY 15 2015 SOME LOW CLOUDS REMAIN ACROSS SOUTHERN MN AND WESTERN WI AS A WARM FRONT CONTINUES TO MOVE NORTH THROUGH IOWA. AREAS OF MVFR CIGS ARE POSSIBLE OVERNIGHT THROUGH SATURDAY MORNING...ESPECIALLY FROM 12Z-15Z SATURDAY AS THE FRONT MOVES INTO SOUTHERN MN. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD DEVELOP OVER WESTERN MN SATURDAY MORNING...AND SPREAD INTO CENTRAL AND EASTERN MN BETWEEN 18Z-00Z. BRIEF PERIODS OF IFR CONDITIONS ARE POSSIBLE IN ANY STORMS THAT DEVELOP...AS WELL AS GUSTY WINDS AND A CHANCE OF HAIL IN THE STRONGEST STORMS...ESPECIALLY AT AXN AND RWF DURING SATURDAY AFTERNOON AND EVENING. KMSP...SCATTERED/BROKEN AREAS OF LOW CLOUDS WILL CONTINUE OVERNIGHT...AND MVFR CIGS ARE POSSIBLE BETWEEN 12Z-15Z AHEAD OF A WARM FRONT MOVING THROUGH SOUTHERN MN. CIGS SHOULD REBOUND LATER SATURDAY MORNING...BUT THUNDERSTORM CHANCES WILL INCREASE DURING THE AFTERNOON. PERIODS OF IFR CONDITIONS ARE POSSIBLE IN THE THUNDERSTORMS...AND WILL BECOME MORE LIKELY AFTER 00Z AS STORM CHANCES INCREASE. /OUTLOOK FOR KMSP/ SUN...VFR WITH SCATTERED IFR/TSRA. WINDS S AT 15-25 KTS. MON...VFR. WINDS NW AT 15-25 KTS. TUE...VFR. WINDS N AT 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...LS AVIATION...ADL
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1018 AM CDT SAT MAY 16 2015 .UPDATE...WIDESPREAD CLOUD COVER PREVALENT OVER THE REGION THIS MORNING SHOULD CONTINUE TO SLOW THE WARMING PROCESS. LATEST HRRR APPEARS TO WARM THE REGION UP A LITTLE TOO FAST COMPARED TO LATEST OBSERVATIONS. CURRENT FORECAST MAX TEMPS IN THE MID 80S STILL LOOKS ATTAINABLE...JUST MAY TAKE A LITTLE LONGER TO ACHIEVE. AREA SOUNDINGS SHOW DEEP MOISTURE IN PLACE THIS MORNING WITH PW VALUES RUNNING CLOSE TO 1.75 INCHES. BEST LOW LEVEL MOISTURE REMAINS OVER THE SOUTH...WHILE ON THE JAN SOUNDING THIS MORNING A DRY LAYER EXISTED FROM 800-950 MB. LOOKING AT THE HRRR DATA...THIS DRY LAYER MAY SERVE TO SLOW CONVECTIVE INITIATION UNTIL TEMPS CAN REACH INTO THE LOWER 80S. CURRENT FORECAST PACKAGE APPEARS ON TRACK./26/ && .AVIATION...UNDER SOUTHERLY MOIST FLOW EXPECT LINGERING IFR CEILINGS IN THE SOUTHWEST TO LIFT UP TO MVFR BY 17Z. SHRA/TSRA CHANCES(IFR/MVFR CONDITIONS) WILL BE LIKELY FOR THE WHOLE CWA FOR THIS AFTERNOON AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST. THE DISTURBANCE WILL COMBINE WITH DAYTIME HEATING TO BRING GOOD PCPN COVERAGE. SO INTERESTS SHOULD PLAN FOR TSRA AT ALL SITES FOR THIS AFTERNOON. SHRA/TSRA WILL DIMINISH EARLY THIS EVNG WITH A FEW SHRA LINGERING OVERNIGHT. LATEST GUIDANCE SUGGEST WIDESPREAD IFR STRATUS WILL DEVELOP LATE TONIGHT INTO EARLY SUNDAY MRNG. /17/EC/ && .PREV DISCUSSION... /ISSUED 436 AM CDT SAT MAY 16 2015/ DISCUSSION... TODAY THROUGH SUNDAY NIGHT... FORECAST THINKING REMAINS THE SAME FOR TODAY AS A PERSISTENT TROUGH TO RIDGE PATTERN OVER THE CENTRAL/EASTERN CONUS CONTINUES TO PROMOTE VERY MOIST SOUTHERLY FLOW JUXTAPOSED BY DISTURBED SOUTHWESTERLY FLOW ALOFT. LATEST HIGH-RES GUIDANCE CONTINUE TO SUGGEST WEATHER TRENDS SIMILAR TO YESTERDAY. SHOWER/THUNDERSTORM ACTIVITY WILL REGENERATE WITH DAYTIME HEATING AHEAD OF ANOTHER UPPER LEVEL SHORTWAVE TROUGH... AND MAY BECOME FAIRLY WIDESPREAD IN THE AFTERNOON. 20-30KTS OF LOW/MID LEVEL FLOW WILL SUPPORT SOME MULTI-CELL STORM ORGANIZATION WITH STEEP LOW LEVEL LAPSE RATES AND FLOW SUPPORTIVE OF STRONG TO PERHAPS EVEN A FEW SEVERE WIND GUSTS. THIS WILL ESPECIALLY BE THE CASE WHERE STORMS ANCHOR ALONG OUTFLOW BOUNDARIES DURING PEAK HEATING...AND WHERE THE BOUNDARIES ARE ORIENTED MORE WNW-ESE AND ORTHOGONAL TO SSW LOW LEVEL SHEAR VECTORS. EXPECT ANY SEVERE WEATHER OCCURRENCES TO BE VERY ISOLATED AND WILL KEEP THE MENTION OUT OF THE HAZARDOUS WEATHER PRODUCTS FOR NOW. GIVEN SUBSTANTIAL OUTFLOW MOTIONS AND HIGH COVERAGE OF PRECIPITATION AGAIN TODAY...HAVE FOLLOWED HIGHER GUIDANCE POPS. CONVECTION WILL DIMINISH EARLY IN THE EVENING AND DO NOT EXPECT IT TO PERSIST AS LONG AS IT DID LAST NIGHT. SUNDAY WILL SEE SOMEWHAT OF A REPEAT OF THIS PATTERN...BUT BETTER CONVECTIVE PRECIPITATION COVERAGE MAY HOLD OFF UNTIL A STRONGER BOUNDARY APPROACHES LATE SUNDAY NIGHT IN NORTHWEST PORTIONS OF THE ARKLAMISS. /EC/ MONDAY INTO SATURDAY...THE MED RANGE/LONG TERM LOOKS TO REMAIN A BIT ON THE ACTIVE SIDE WRT PRECIP POTENTIAL. DEEP MOISTURE (PWS 1.6-1.8 IN) WILL RESIDE OVER THE REGION THROUGH MUCH OF THE PERIOD WITH THE PRESENCE OF A WEAK SFC BOUNDARY IN THE VICINITY THROUGH THIS TIME AS WELL. ADDITIONALLY...GLOBAL MODELS CONTINUE TO SHOW SEVERAL DISTURBANCES INTERACTING WITH THE MOISTURE AND BOUNDARY TO HELP TRIGGER SHOWERS/STORMS. AT THIS TIME...THE MOST PREVALENT WAVE LOOKS TO IMPACT THE CWA ON MON. IN RESPONSE TO THIS...40-70% POPS ARE IN PLACE TO CAPTURE THE POTENTIAL. THE OVERALL EVOLUTION OF ACTIVITY ON MON IS NOT CLEAR AS SOME OF THE AREA COULD SEE PRECIP EARLY IN THE DAY FROM SOME LEFT OVER STORMS MOVING OUT OF AR WITH OTHER SOLUTIONS SHOWING ACTIVITY WAITING UNTIL THE AFTERNOON. THERE IS SOME POTENTIAL FOR STRONGER STORMS AS BETTER MID LEVEL LAPSE RATES WILL BE IN PLACE ALONG WITH HIGHER DEEP LAYER SHEAR. OVERALL...HOW THINGS EVOLVE AND TIMING WILL PLAY A KEY ROLE AND WITH UNCERTAINTY IN THOSE...WILL NOT MENTION ANYTHING IN THE HWO AT THIS TIME...BUT WILL KEEP A CLOSE EYE ON TRENDS. LINGERING PRECIP CHANCES WILL EXIST THROUGH THE REMAINDER OF THE WEEK WITH AT LEAST ONE OPPORTUNITY FOR A DECENT SHOT AT MORE PRECIP. AT THIS TIME...THU INTO THU NGT MAY BE THAT PERIOD AS MOST MODELS SHOW ANOTHER DECENT WAVE AND GOOD QPF SIGNAL. AS FOR TEMPS...PERSISTENCE TYPE FORECAST IS IN ORDER AND THE BLENDED GUID SEEMS TO BE ON TARGET. EXPECT TEMPS TO REMAIN JUST A BIT WARMER THAN CLIMO READINGS WITH HIGHS ROUGHLY 85-90 AND LOWS 65-70. SOUTHERN AREAS WILL LIKELY BE ON THE WARMER SIDE OF THOSE RANGES AS THEY WILL BE FURTHER REMOVED FROM THE LINGERING SFC BOUNDARY. /CME/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 86 70 87 70 / 62 33 43 32 MERIDIAN 84 69 86 68 / 70 35 44 29 VICKSBURG 86 71 88 72 / 60 26 41 32 HATTIESBURG 85 70 87 70 / 70 45 41 20 NATCHEZ 85 72 87 72 / 59 29 40 23 GREENVILLE 85 71 86 71 / 64 34 59 50 GREENWOOD 85 70 87 70 / 69 34 49 49 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1201 AM CDT Sat May 16 2015 .SHORT TERM...(This Evening through Saturday) Issued at 222 PM CDT FRI MAY 15 2015 A weak impulse is currently moving across the Missouri Ozarks and lifting northeastward. Scattered convection has developed ahead of the impulse across central Missouri and the eastern Ozarks where instability is better. This convection will continue to move northward. There appears to be a little subsidence behind the exiting upper level impulse. Additional isolated to widely scattered convection is possible elsewhere through the evening hours where the sun is able to add some instability but it will be limited. Short range models like the HRRR and RUC13 keep most of the convection redevelopment towards central Missouri this evening. Later this evening...for the most part the weather should be fairly quiet. Will mention the possibility of some patchy fog near large lakes and river valleys by sunrise in the morning. Forecast cape for tomorrow approach 2500 J/KG but the deep shear will be limited around 20 to 25 knots for most of the day over the Ozarks. The better dynamics will be just to our west across Kansas and Oklahoma for severe convection. Scattered convection will develop around the Missouri Ozarks by midday to afternoon on Saturday with the best potential over south central Missouri. Models indicate that the leftover severe convection that develops across Kansas and Oklahoma will move into southeast Kansas and extreme western Missouri late Saturday evening and overnight. There is a slight risk for severe weather Saturday evening for these areas with the main threat being damaging wind gusts and large hail. MUCape will be between 1500 to 2000 J/KG with Bulk shear values increasing to 40 knots by Saturday evening over southeast Kansas and western Missouri. Line segments and clusters of convection is expected moving eastward from Kansas and Oklahoma into the western Missouri Ozarks. Total QPF this weekend is expected on average between 0.5 to 1.0 of an inch. .LONG TERM...(Sunday through Friday) Issued at 222 PM CDT FRI MAY 15 2015 The main upper level support and energy moves away from the area on Sunday and Sunday night. Models indicate the best potential for additional convection develop on Sunday afternoon and evening will be south and east of I-44 across south central Missouri. There is a very limited potential for a couple strong storms over south central Missouri Sunday evening. A cold front finally makes some progress into the area by Monday. There will be a chance for showers and storms across south central Missouri before the front clears through the area. Cool and drier air will move in for Monday night through Tuesday evening. Temperatures will be below average. The weather pattern becomes unsettled again by the middle and end of next week. Another broad trough develops across the western U.S. and weak shortwaves and impulses will move across the central Plains and Midwest starting Wednesday through Friday with scattered rain chances and thunderstorms. && .AVIATION...(For the 06Z TAFS through 06Z Saturday Night) Issued at 1148 PM CDT FRI MAY 15 2015 An area of showers and perhaps a few thunderstorms will spread north into portions of southern Missouri late tonight and early Saturday morning. MVFR ceilings will also accompany this activity...especially around Branson. There is even some potential for IFR ceilings across south-central Missouri. Confidence in this scenario remains low enough to preclude IFR from the TAFs. Additional scattered thunderstorm development is then expected from late Saturday morning into early Saturday afternoon across western Missouri. MVFR and brief IFR conditions can be expected with any thunderstorms. Outside of thunderstorms, surface winds will increase out of the south on Saturday and will become gusty. Yet another round of thunderstorms will then be possible across western Missouri late Saturday evening towards the end of the TAF period. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Griffin LONG TERM...Griffin AVIATION...Schaumann
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
333 PM CDT SAT MAY 16 2015 .SHORT TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 332 PM CDT SAT MAY 16 2015 SEVERE POTENTIAL TONIGHT REMAINS THE PRIMARY FORECAST CONCERN. SCATTERED CONVECTION SUNDAY FOLLOWED BY COOLER TEMPERATURES TO BEGIN THE WORK WEEK ARE SECONDARY CONCERNS. 18Z SOUNDING AT KOAX SHOWED ALMOST 1500 J/KG OF SURFACE-BASED CAPE...WHICH IS MUCH LOWER THAN THE 2500 J/KG SHOWN BY OPERATIONAL RAP ANALYSIS OBSERVED ON SPC MESOANALYSIS PAGE. SOUNDING ALSO SHOWED ALMOST 50 J/KG OF CONVECTIVE INHIBITION. HOWEVER AXIS OF HIGHEST CAPE NEAR OUR CWA DEPICTED BY RAP STILL LOOKS GOOD STRETCHING FROM EASTERN SOUTH DAKOTA INTO WESTERN IOWA WHERE AVERAGE TEMPS AND DEW POINTS WERE IN THE UPPER 70S AND UPPER 60S. EXPERIMENTAL HRRR SUGGESTS A FEW STORMS WILL FIRE THIS AFTERNOON FROM SOUTHEAST SOUTH DAKOTA INTO EASTERN NEBRASKA ON WESTERN SIDE OF INSTABILITY GRADIENT...AND ALREADY ARE SEEING THE START OF THAT CONVECTION IN SOUTH DAKOTA AND NEAR THE OMAHA METRO. THESE STORM SHOULD CONTINUE TO MOVE OFF TO THE NORTHEAST RATHER QUICKLY...AND COULD SEE A WIND/HAIL EVENT BEFORE EXITING OUR CWA LATE THIS AFTERNOON. ATTENTION THEN TURNS TO POTENTIALLY MORE WIDESPREAD SEVERE IGNITING WELL TO OUR SOUTHWEST IN THE HIGHS PLAINS FROM WESTERN NEBRASKA INTO THE TEXAS PANHANDLE. HI-RES MODELS ALL HAVE SOME VARIATION IN THIS CONVECTION...AND SPREAD IT INTO SOUTHEAST NEBRASKA LATER THIS EVENING. WHAT KIND OF ATMOSPHERE WILL BE AVAILABLE FOR THOSE STORMS IS STILL IN QUESTION...MAINLY DUE TO ON-GOING STORMS IN CENTRAL KANSAS INTO NORTH CENTRAL OKLAHOMA. THE MOST LIKELY SCENARIO BASED ON LATEST HRRR AND RAP IS SOME OF THE KANSAS CONVECTION WILL TRACK NORTHEAST INTO EASTERN NEBRASKA LATE THIS AFTERNOON THEN EXIT TO THE EAST THIS EVENING. GIVEN CURRENT INSTABILITY AND SHEAR...ROTATING STORMS ARE LIKELY WITH AT LEAST SOME HAIL THREAT AND MOST NOTABLY WIND. TORNADOES ARE STILL A THREAT AS WELL IF FORECAST STORM- RELATIVE 0-1KM HELICITY NEAR 150 M2/S2 IS REALIZED. MODELS DEPICT THIS AREA OF CONVECTION WILL BOW OUT ACROSS WESTERN IOWA BEFORE EXITING TO OUR EAST. THEN SECONDARY SURGE OF STORMS IS SLATED TO RACE NORTHEAST FROM OKLAHOMA PANHANDLE AND ENTER SOUTHEAST NEBRASKA AT MID TO LATE EVENING. SOME RECOVERY IN AIRMASS IS LIKELY AFTER EARLIER STORMS. AN INCREASE IN LOW LEVEL JET TO NEAR 50KT IS LIKELY AS INCREASINGLY DIFFLUENT MID LEVEL FLOW OVERSPREADS THE PLAINS. SO LATER-EVENING STORMS WILL STILL HAVE VIGOROUS WIND FIELDS TO PLAY WITH... SUPPORTING AT LEAST SOME TORNADO AND WIND THREAT PAST DARK. TREND IN HOURLY UPDATES OF HRRR FORECASTS HAS BEEN FOR NORTHERNMOST SEVERE STORMS TO ONLY GRAZE FAR SOUTHEAST NEBRASKA IN THE 03Z TO 06Z TIMEFRAME. SO WILL KEEP A CLOSE EYE ON IF THIS TREND CONTINUES. WHILE SECOND LINE OF STORMS MOVES EAST OF OUR CWA AFTER MIDNIGHT...MORE SHOWERS/STORMS ARE FORECAST TO DEVELOP IN WESTERN NEBRASKA AND TRACK INTO NORTHEAST NEBRASKA OVERNIGHT AS UPPER LOW MOVES INTO THE NORTHERN PLAINS. A WAVE ROTATING AROUND THIS FEATURE WILL LIKELY IGNITE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MUCH OF SUNDAY IN SOUTH DAKOTA AND NORTHERN NEBRASKA. GFS SUGGESTS UP TO 1000 J/KG OF SURFACE-BASED CAPE WILL BE AVAILABLE FOR THIS ACTIVITY INTO THE AFTERNOON. AFTER WAVE PASSES SUNDAY AFTERNOON...STRONG COLD ADVECTION WILL OVERSPREAD OUR AREA...DROPPING 850 TEMPERATURES TO BELOW 0C ON MONDAY IN OUR NORTH. COULD SEE A PASSING SHOWER ALONG THIS COLD PUSH SUNDAY NIGHT...BUT THE MAIN WEATHER STORY WILL BE COOLER AND DRIER AIR BEING PUSHED INTO THE REGION ON BRISK NORTHWEST WINDS MONDAY. HIGHS IN THE LOWER 60S SHOULD BE ALL WE CAN MUSTER THEN. THE COOL WEATHER CONTINUES INTO TUESDAY WHEN SURFACE HIGH PRESSURE SETTLES INTO THE REGION. COULD SEE SUB-40 LOWS IN MANY AREAS TUESDAY MORNING. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 332 PM CDT SAT MAY 16 2015 MID LEVEL FLOW PATTERN WILL RELOAD AS ANOTHER UPPER LOW SETTLES INTO THE SOUTHWEST STATES AT MID WEEK ON HEELS OF EXITING NORTHERN PLAINS LOW. THIS WILL BRING GENERALLY SOUTHWEST FLOW OVER THE MIDDLE OF THE COUNTRY...WITH A POTENT WAVE EJECTING INTO THE PLAINS ON WEDNESDAY. THAT WAVE WILL BRING OUR NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS BEGINNING TUESDAY NIGHT BEFORE EXITING WEDNESDAY NIGHT. MOISTURE RETURN LOOKS MINIMAL...SO SEVERE STORMS APPEAR UNLIKELY DESPITE THE CALENDAR SAYING WE ARE IN MID TO LATE MAY. SOME WEAK RIDGING BEHIND EXITING WAVE SUGGESTS RAIN CHANCES WILL BE AT A MINIMUM TO END THE WEEK...BUT SOUTHWESTERN TROUGH AXIS BEGINS LIFTING TOWARD THE PLAINS BY SATURDAY. WILL BRING STORM CHANCES BACK INTO THE FORECAST THEN...BUT DETAILS WILL HAVE TO BE WORKED OUT WITH TIME ON DEGREE OF POTENTIAL SEVERE RISK. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1230 PM CDT SAT MAY 16 2015 ALL THREE TAF SITES WERE VFR AS OF 17Z. A BAND OF SHOWERS AND THUNDERSTORMS IS STILL EXPECTED TO DEVELOP ACROSS KANSAS AND MOVE ACROSS ALL THREE TAF SITES THIS EVENING AND OVERNIGHT. ISOLATED TSRA COULD DEVELOP ABOUT ANYTIME AROUND 21Z BUT EXPECTING THE BETTER CHANCE OF ORGANIZED STORMS TO OCCUR AFTER 00Z. THIS IS COVERED WITH TEMPO GROUPS IN ALL TAFS AND WILL LIKELY NEED TO BE ADJUSTED ONCE ACTIVITY DEVELOPS. THUNDERSTORMS WILL MOVE NORTHEAST LATE IN THE FORECAST PERIOD AND HAVE TRENDED THEM OUT OF KOMA AND KLNK AFTER 14Z. DUE TO WRAP AROUND ACTIVITY AROUND DEEP SURFACE LOW OVER EASTERN SOUTH DAKOTA BY 15Z...WILL KEEP THREAT OF -RA OR EVEN -TSRA IN THE KOFK VICINITY THROUGH 18Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...MEYER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
850 PM PDT SUN MAY 17 2015 .SYNOPSIS...PRECIPITATION CHANCES WILL SPREAD FROM WEST TO EAST ACROSS THE REGION TONIGHT AND MONDAY AS A LOW PRESSURE SYSTEM MOVES INLAND. THIS SYSTEM WILL THEN MOVE SLOWLY NORTHEAST WITH SHOWERS LINGERING MAINLY NORTH OF LAS VEGAS TUESDAY INTO TUESDAY NIGHT. YET ANOTHER STORM WILL IMPACT THE AREA LATER IN THE WEEK. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE WEEK. && .UPDATE...RECENT RADAR RETURNS INDICATED AN AREA OF LIGHT SHOWERS DEVELOPING OVER DEATH VALLEY NATIONAL PARK ON THE SOUTHEAST PERIPHERY OF THE CENTRAL CALIFORNIA LOW. THE LATEST HRRR AND 00Z NAM QPF DEPICTIONS PICKED UP THIS GENERAL TREND AND SPREAD PRECIPITATION UP THROUGH THE PAHRUMP VALLEY...AMARGOSA VALLEY AND BEATTY BEFORE 06Z. RAINFALL AMOUNTS ARE EXPECTED TO BE QUITE LIGHT GIVEN THE LIGHT RETURNS AND THE 15-20 MPH NORTHWARD MOVEMENT OF THE SHOWERS. THE POP/WX/QPF GRIDS WERE ADJUSTED ACCORDINGLY. OTHERWISE...THE FORECAST IS ON TRACK WITH SHOWERS SLOWLY SPREADING TO THE SOUTHEAST MONDAY MORNING THROUGH AFTERNOON. && .AVIATION...FOR MCCARRAN...SOUTHEAST WINDS GUSTING AROUND 20-25 KTS ARE EXPECTED TO DECREASE BEFORE 06Z AND BECOME A MORE TYPICAL SOUTH/SOUTHWEST DRAINAGE WIND AROUND 10 KTS THE REST OF THE NIGHT. WINDS MAY BECOME LIGHT AND VARIABLE MONDAY MORNING BUT WINDS BY EARLY AFTERNOON WILL BE SOUTHERLY 10-15 KTS WITH GUSTS POSSIBLY UP TO 20 KTS. SCT CLOUDS WITH BASES AS LOW AS 10 KFT WILL LINGER THROUGH TONIGHT AND WILL PROBABLY BECOME BKN MONDAY MORNING AND COULD LOWER TO 8 KFT AS SHOWERS MOVE ACROSS THE AREA BY LATE MORNING OR EARLY AFTERNOON. SHOWERS WILL BE POSSIBLE THROUGH MONDAY EVENING BUT SHOULD END OVERNIGHT. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...SOUTH TO SOUTHEAST WINDS BETWEEN 10-15 KTS WITH GUSTS 20-25 KTS OVER MOST AREAS THROUGH MUCH OF TONIGHT WITH SCATTERED TO NUMEROUS SHOWERS OVER THE SOUTHERN SIERRA. ISOLATED SHOWERS WILL BE POSSIBLE ACROSS THE REST OF INYO COUNTY AND OVER ESMERALDA AND CENTRAL NYE COUNTIES. MAINLY TYPICAL NIGHT TIME DRAINAGE WINDS WILL DEVELOP LATER TONIGHT. PRECIPITATION CHANCES WILL SPREAD ACROSS THE REST OF THE AREA MONDAY AS A STORM SYSTEM MOVES THROUGH THE REGION. SOUTHERLY WINDS WILL INCREASE AGAIN MONDAY TO 10-18 KTS WITH GUSTS 20-30 KTS. CIGS WITH SHOWERS TONIGHT AND MONDAY WILL LOWER TO 5-7 KFT. && .PREV DISCUSSION... 240 PM PDT SUN MAY 17 2015 .SHORT TERM...THROUGH TUESDAY NIGHT. AN UPPER LOW WAS ALONG THE COAST THIS AFTERNOON WITH WEAK CONVECTION ACROSS PORTIONS OF THE FORECAST AREA. WEB CAMS AND RADAR SHOWED SOME SHOWERS OVER THE SIERRA. OTHERWISE THERE IS NO REAL EVIDENCE OF PRECIPITATION REACHING THE GROUND SO FAR. THE UPPER LOW WILL MOVE INLAND TONIGHT WITH PRECIPITATION CHANCES INCREASING IN THE SIERRA WITH AT LEAST A SLIGHT CHANCE ACROSS MUCH OF INYO COUNTY AS WELL AS ESMERALDA...CENTRAL NYE AND NORTHERN LINCOLN COUNTIES. THE LOW CENTER WILL MOVE TO ROUGHLY THE NV/CA LINE MONDAY WITH PRECIPITATION CHANCES SPREADING TO ALL BUT SOUTHERN SAN BERNARDINO COUNTY. THE BEST CHANCE OF ANY DECENT PRECIPITATION REMAINS OF THE HIGHER TERRAIN. THE LOW WILL START TO WEAKEN MONDAY NIGHT BUT PRECIPITATION CHANCES WILL CONTINUE IN MOST AREAS. THE LOW WILL CONTINUE TO WEAKEN AND MOVE NORTHEAST TUESDAY WITH WITH PRECIPITATION CHANCES LINGERING NORTH OF LAS VEGAS. WITH THE AREA BETWEEN TWO SYSTEMS TUESDAY NIGHT WE SHOULD SEE ANY LINGERING PRECIPITATION ENDING BY LATE EVENING. TEMPERATURES WILL REMAIN BELOW NORMAL ACROSS THE AREA THROUGH TUESDAY. SNOW LEVELS WITH THIS SYSTEM WILL MAINLY BE ABOVE 8000-8500 FEET. THE HIGHER ELEVATIONS OF THE SIERRA AND THE WHITE MOUNTAINS AND SPRING MOUNTAINS COULD SEE A FEW INCHES OF SNOW. .LONG TERM...WEDNESDAY THROUGH SUNDAY NIGHT. WELL THE VACATION FROM TYPICAL MAY WEATHER CONTINUES INTO THE START OF THE MEMORIAL DAY WEEKEND. YET ANOTHER COLD MID/UPPER LOW AWAITS TO MOVE ON IN FOR WEDNESDAY AS IT APPROACHES THE CENTRAL COAST OF CALIFORNIA. AS THE LOW APPROACHES THE COAST, IT SHOULD SPREAD IN ENOUGH MID-LEVEL MOISTURE TO SPARK OFF A FEW SHOWERS AND PERHAPS A THUNDERSTORM OVER THE NORTHWEST CWFA ESPECIALLY THE SOUTHERN SIERRA, WHITE MOUNTAINS, THE OWENS VALLEY AND ESMERALDA COUNTY IN THE LATE MORNING AND AFTERNOON. OTHERWISE LOOK FOR A DRY DAY WITH WINDS PICKING UP IN THE AFTERNOON FROM THE SOUTH TO SOUTHWEST AND GUSTING TO 20-30 MPH. HIGH TEMPS WILL WARM UP A FEW DEGREES FROM TUESDAY BUT STILL BE 5-7 DEGREES BELOW NORMAL. MOST OF WHATEVER CONVECTIVE ACTIVITY WE SEE DURING THE DAY ON WEDNESDAY SHOULD DIE OFF WITH THE LOSS OF HEATING DURING THE EARLY EVENING. THE CENTER OF THE LOW ITSELF IS EXPECTED TO PASS NEAR POINT CONCEPTION ON THURSDAY AFTERNOON AND HEAD TOWARD THE COAST OF SOCAL BY THURSDAY NIGHT. ONCE AGAIN IT APPEARS WE COULD MAINLY SEE DIURNALLY DRIVEN AFTERNOON AND EVENING SHOWERS AND PERHAPS A FEW THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE AREA. HOWEVER, SOME SHOWERS COULD STICK AROUND INTO THURSDAY NIGHT AS THE LOW CENTER GETS CLOSER. SNOW LEVELS SHOULD DROP TO 8500 FEET THEN SO THE HIGHEST ELEVATIONS MAY SEE A FEW INCHES OF SNOW IF ANY HEAVIER OR STEADIER SHOWERS PASS OVER THEM. THE LOW CENTER IS EXPECTED TO PASS ACROSS SOCAL ON FRIDAY DURING THE MORNING THEN LIFT NORTHEAST INTO MOHAVE COUNTY BY THE AFTERNOON. AT THIS TIME, THE OPERATIONAL MODELS KEEP THE BULK OF THE MOISTURE NORTH OF WHERE THE CENTER OF THE LOW TRACKS AND MOST OF THE QPF THEY DEVELOP. THUS WE HAVE CONTINUED TO KEEP THE GREATEST SHOWER CHANCES NORTH OF I-40 AND OVER THE HIGHER ELEVATIONS. HIGH TEMPS ON THURSDAY AND FRIDAY SHOULD BE ABOUT 8-12 DEGREES BELOW NORMAL. EVEN WHERE WE STAY DRY THERE LOOKS TO BE A DECENT CIRRUS SHIELD PASSING OVER THE AREA ON THURSDAY AS THE JET STREAM PASSES BY JUST TO OUR SOUTH AND ENOUGH MID-LEVEL MOISTURE ON FRIDAY TO GENERATE PLENTY OF CUMULUS. THUS THE CLOUDS AND COOLER AIR ALOFT COURTESY OF THE LOW CENTER WILL AID GREATLY IN HOLDING DOWN TEMPS. MOST SHOWER ACTIVITY SHOULD END BY FRIDAY NIGHT AS THE LOW CENTER PULLS EAST, HOWEVER, AS THE FLOW ALOFT TURNS NORTHWEST ADDITIONAL ENERGY DROPPING SOUTH MAY TRIGGER A FEW SHOWERS OVER THE SOUTHERN GREAT BASIN ON SATURDAY AND TO A LESSER EXTENT ON SUNDAY. ELSEWHERE, IT SHOULD REMAIN DRY. DESPITE THE FLOW ALOFT TURNING NORTH, TEMPS WILL START TO WARM IN RESPONSE TO RISING HEIGHTS AND MAY GET BACK CLOSER TO NORMAL VALUES FOR HIGHS BY NEXT SUNDAY. ENJOY THE SAVINGS ON YOUR ELECTRIC BILL WHILE THE AIR CONDITIONERS AND FANS GET A BREAK. && && .SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ UPDATE...ADAIR SHORT TERM/AVIATION...HARRISON LONG TERM...STACHELSKI FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
325 PM MDT SAT MAY 16 2015 .SYNOPSIS... PRECIPITATION AND WINDS OVERALL SHOULD DECREASE TONIGHT...WITH QUIET AND WARMER WEATHER SUNDAY. ANOTHER FRONT AND STORM SYSTEM WILL COLLIDE BY MONDAY NIGHT AND TUESDAY...WITH ANOTHER WET AND COOLER PERIOD...ESPECIALLY FOR LOCALES EXTENDING FROM THE RIO GRANDE VALLEY EASTWARD ACROSS THE EASTERN PLAINS. DRYING EXPECTED THEREAFTER WITH SOME WARMING BUT SOME STORMS WILL STILL BE POSSIBLE ACROSS AT LEAST OVER THE FAR EASTERN PLAINS AND NORTHERN MOUNTAINS THE END OF NEXT WEEK. && .DISCUSSION... PRECIPITATION AND WINDS OVERALL SHOULD DECREASE OVERNIGHT...BUT WITH SOME POSSIBLE EXCEPTIONS. WIND ADVY SPOTTY AT BEST THIS AFTERNOON AND STRONGEST GUSTS APPEAR TO HAVE BEEN CONVECTION RELATED...HOWEVER...H7 WINDS INCREASE OVERNIGHT OVER PARTS OF THE NORTHEAST AS THE UPPER LOW/TROF SWINGS OUT INTO THE PLAINS STATES...SO WILL KEEP THE NPW GOING. WILL ALSO KEEP THE CURRENT WSW AS IS...WITH GFS/NAM NOT INDICATING MUCH SNOW AFTER 00Z. THE HRRR ON THE OTHER HAND...KEEPS SOME SNOW GOING OVER THE NRN SANGRE DE CRISTO MTS...AND THE FORECAST MOIST W-NWLY BOUNDARY LAYER WINDS INTO THE SANGRES COULD CONTINUE TO ACCUMULATE SOME SNOW INTO THE LATE EVENING. ARRGH...WILL HAVE TO CONTINUE TO MONITOR...BUT GRIDS HAVE ANOTHER 1 TO 3 INCHES IN THIS AREA TONIGHT...ALTHOUGH THAT WOULD BE UNDERDONE IF HRRR IS RIGHT. BUT NO MODEL SEEMS TO BE DOING THAT WELL TODAY. DRIER AND WARMER SUNDAY INTO MONDAY. THEN ANOTHER WETTER AND COOLER PERIOD MONDAY NIGHT THROUGH TUESDAY AS ANOTHER SYSTEM COMING FROM THE WEST AND A FRONT FROM THE EAST COLLIDE TO PRODUCE WIDESPREAD PRECIPITATION. TRIMMED DOWN POPULATED QPF WHICH TOTALED A LARGE SWATH OF A COUPLE OF INCHES JUST MONDAY NIGHT ALONG THE CENTRAL MT CHAIN TO THE PECOS VALLEY. BUT SOME GENEROUS AMOUNTS POSSIBLE TUESDAY AS WELL AS THE UPPER SYSTEM SWINGS OVER NE NM. H7 TEMPS NOT AS COLD AS WITH PRESENT SYSTEM SO NOT ANTICIPATING THE LOWER SNOW LEVELS THAT HAVE BEEN OBSERVED TODAY. LOTS OF VARIATION MID TO LATE NEXT WEEK...THE GFS IS DRIER AND WINDY WHILE THE ECMWF IS WETTER THANKS TO A FRONT ON FRIDAY...SURPRISE. IN ANY EVENT...THE UNSETTLED WEATHER PATTERN APPEARS TO CONTINUE INTO THE MEMORIAL DAY WEEKEND. && .FIRE WEATHER... NO WIDESPREAD FIRE WEATHER CONCERNS THROUGH THE FORECAST PERIOD AS THE WEATHER PATTERN CONTINUES TO FAVOR UNSETTLED...ACTIVE WEATHER AND SEASONABLY COOLER THAN NORMAL TEMPERATURES. CURRENT UPPER LEVEL TROUGH IS CROSSING NM THIS PM AND WILL SHIFT TO THE EAST TONIGHT. SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE EVENING HOURS...MAINLY NORTH OF I 40. SHOWERS MAY LINGER OVER THE NORTH LATE TONIGHT. RH RECOVERIES WILL BE GOOD TO EXCELLENT. A MAINLY DRY DAY IS IN STORE SUNDAY AS A WEAK UPPER LEVEL RIDGE MOVES OVER. DESPITE THE RIDGE...HIGH TEMPERATURES REMAIN BELOW AVERAGE FOR MID MAY. MODELS INDICATING RESIDUAL MOISTURE WILL COMBINE WITH DAYTIME HEATING TO PRODUCE A FEW SHOWERS AND MAYBE THUNDERSTORMS OVER THE NORTHERN MOUNTAINS. A BACK DOOR COLD FRONT WILL DROP SOUTH INTO THE NORTHEAST EAST SUNDAY NIGHT. IT WILL STALL MONDAY BEFORE RACING SOUTH AND WEST MONDAY NIGHT. STRONG EAST WINDS INTO THE RIO GRANDE VALLEY ARE POSSIBLE. MEANWHILE THE NEXT UPPER LEVEL TROUGH WILL BE APPROACHING MONDAY THEN SWEEP ACROSS THE STATE MONDAY NIGHT INTO TUESDAY. THE COMBINATION OF LOW LEVEL MOISTURE BEHIND THE FRONT...INSTABILITY FROM THE UPPER TROUGH...AND DEEP MOISTURE GETTING DRAWN NORTHWEST INTO NM FROM TX WILL RESULT IN A SIGNIFICANT RAIN EVENT FOR MUCH OF THE FORECAST AREA...WITH THE LEAST FAVORED AREA THE SOUTHWEST AND THE MOST FAVORED AREA ALL OF THE EAST. ALL THE MODELS HAVE A FAIRLY WIDESPREAD...SOAKING RAIN EVENT WITH ONE TO TWO INCH RAIN AMOUNTS FOR THE EASTERN PLAINS AND LOCALLY UP TO THREE INCHES IN THE MONDAY NIGHT THROUGH TUESDAY TIME PERIODS. YET ANOTHER STORM WILL BE ORGANIZING OFF THE CA COAST LATER NEXT WEEK. THE FAR EASTERN PLAINS WILL BE UNDER THE GUN FOR SHOWERS AND STORMS WEDNESDAY INTO FRIDAY. A DRY LINE WILL WOBBLE BACK WEST AT NIGHT AND TO THE EAST DURING THE DAY. ELSEWHERE SHOULD BE MOSTLY DRY. ALL AREAS WILL REMAIN BELOW NORMAL. WINDS WILL BE ON THE INCREASE NEXT FRIDAY AND SATURDAY. BRIEF CRITICAL FIRE WEATHER CONDITIONS ARE NOT OUT OF THE QUESTION OVER THE SOUTHERN PORTION OF THE MIDDLE RIO GRANDE VALLEY FRIDAY AFTERNOON. A PORTION OF THE ABOVE MENTIONED STORM WILL CROSS NM SATURDAY WHILE ANOTHER PORTION HANGS BACK OVER UT AND AZ. THIS LAZY TROUGH WILL INCH ITS WAY EAST WHILE KEEPING SHOWERS AND STORMS IN THE FORECAST FOR THE NORTH AND EAST LATE NEXT WEEKEND INTO EARLY THE FOLLOWING WEEK. 40 && .AVIATION... 18Z TAF CYCLE AN UPPER LEVEL TROUGH WILL SWING ACROSS NM THIS AFTERNOON. A SURFACE COLD FRONT WILL ACCOMPANY THE TROUGH. PLENTY OF LOW LEVEL MOISTURE AND AN UNSTABLE ATMOSPHERE WILL PRODUCE SHOWERS AND THUNDERSTORMS THROUGH AT LEAST 03Z. A FEW STORMS OVER THE NE COULD BE STRONG TO SEVERE THIS PM. BRIEF MVFR TO IFR CONDITIONS LIKELY WITH ANY STORM. WET SNOW WILL FALL IN THE MTS WITH OBSCURATIONS. WIND GUSTS APPROACHING 50 KT WITH THE STRONGEST STORMS. OTHERWISE...MOSTLY VFR CONDITIONS. AREAS OF FOG WILL DEVELOP LATE TONIGHT...ESPECIALLY OVER WRN AND CENTRAL NM WHERE WINDS WILL BE LOWEST. FOR NOW HAVE VCFG IN MANY OF THE TAF SITES. 40 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 37 68 42 77 / 20 0 0 10 DULCE........................... 30 64 35 69 / 40 5 5 20 CUBA............................ 32 64 38 69 / 30 5 5 10 GALLUP.......................... 29 66 35 76 / 20 0 0 10 EL MORRO........................ 28 63 33 69 / 20 0 0 10 GRANTS.......................... 30 67 32 74 / 20 0 0 10 QUEMADO......................... 32 64 34 71 / 10 0 0 5 GLENWOOD........................ 37 72 43 80 / 5 0 0 5 CHAMA........................... 27 59 30 63 / 60 10 10 20 LOS ALAMOS...................... 37 61 44 66 / 30 5 5 10 PECOS........................... 35 62 39 64 / 20 5 5 10 CERRO/QUESTA.................... 29 63 33 64 / 50 10 10 20 RED RIVER....................... 27 53 32 56 / 60 10 10 40 ANGEL FIRE...................... 26 58 30 59 / 50 10 5 30 TAOS............................ 27 64 35 67 / 30 5 5 20 MORA............................ 34 62 38 61 / 30 0 5 20 ESPANOLA........................ 38 68 42 71 / 20 5 5 10 SANTA FE........................ 38 62 44 66 / 20 5 5 10 SANTA FE AIRPORT................ 36 67 40 71 / 20 5 5 10 ALBUQUERQUE FOOTHILLS........... 39 68 43 73 / 20 0 0 10 ALBUQUERQUE HEIGHTS............. 44 70 49 76 / 10 0 0 5 ALBUQUERQUE VALLEY.............. 39 72 46 80 / 10 0 0 5 ALBUQUERQUE WEST MESA........... 43 71 48 77 / 20 0 0 5 LOS LUNAS....................... 39 71 44 78 / 10 0 0 5 RIO RANCHO...................... 42 70 48 76 / 20 0 0 5 SOCORRO......................... 43 74 47 81 / 10 0 0 5 SANDIA PARK/CEDAR CREST......... 38 64 44 70 / 20 0 0 10 TIJERAS......................... 37 68 40 73 / 20 0 0 10 MORIARTY/ESTANCIA............... 32 66 32 70 / 10 0 0 10 CLINES CORNERS.................. 34 65 39 67 / 10 0 0 10 GRAN QUIVIRA.................... 36 66 38 71 / 10 0 0 10 CARRIZOZO....................... 41 69 44 76 / 5 0 0 10 RUIDOSO......................... 40 65 46 72 / 5 0 0 10 CAPULIN......................... 35 67 40 63 / 30 0 10 20 RATON........................... 36 72 41 68 / 30 0 10 30 SPRINGER........................ 38 72 42 68 / 30 0 5 20 LAS VEGAS....................... 36 66 37 65 / 20 0 0 20 CLAYTON......................... 45 76 47 70 / 30 0 5 20 ROY............................. 42 71 45 67 / 20 0 5 20 CONCHAS......................... 47 77 49 75 / 10 0 5 10 SANTA ROSA...................... 45 75 47 76 / 5 0 0 10 TUCUMCARI....................... 48 80 49 78 / 5 0 5 10 CLOVIS.......................... 46 77 48 78 / 5 0 10 10 PORTALES........................ 47 77 49 79 / 5 0 10 10 FORT SUMNER..................... 46 77 48 79 / 5 0 5 10 ROSWELL......................... 48 80 50 84 / 5 0 5 10 PICACHO......................... 44 74 47 76 / 5 0 0 10 ELK............................. 41 69 46 72 / 5 0 5 10 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES... NMZ523-526-529>540. WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ510-511-513-514. && $$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1042 PM CDT SUN MAY 17 2015 .UPDATE... ISSUED AT 1042 PM CDT SUN MAY 17 2015 ROLLA STILL SUSTAINED AT OVER 40KTS WITH TURTLE MOUNTAIN RAWS STILL GUSTING TO 61 MPH. WILL EXTEND THE HIGH WIND WARNING A COUPLE OF HOURS...TILL 1AM CDT. RAP PRESSURE RISES ON THE DECREASE SO A 1AM EXPIRATION SHOULD BE GOOD. UPDATE ISSUED AT 1004 PM CDT SUN MAY 17 2015 HEADLINES WILL REMAIN AS IS. AN ARGUMENT CAN BE MADE FOR A SMALL AREA FOR BLIZZARD HEADLINES WITH BOTH ROLLA AND HARVEY REPORTING STRONG WINDS GUSTING 35-45KTS AND 1/4 MILE VIS IN HEAVY SNOW. HOWEVER...VIS HAVE BEEN JUMPING FROM 1/4 TO 3/4 AND DO NOT FEEL THE SMALL AREA AND TIME DURATION JUSTIFIES AN UPGRADE. THUS WILL MAINTAIN THE WINTER WEATHER ADVISORY AS IS WITH NEAR BLIZZARD WORDING AND OTHER DIRE TERMINOLOGY IN THE OVERVIEW AND SEGMENT. HIGH WIND WARNING OVER MY FAR NORTHEAST EXPIRES AT 11PM. WILL REVISIT IN 30-45 MIN FOR A POSSIBLE EXTENSION. UPDATE ISSUED AT 710 PM CDT SUN MAY 17 2015 RAIN CHANGING OVER TO SNOW AS TEMPERATURES AT THE SURFACE AND ALOFT COOL. HAVE HAD A MIX OF SLEET SOUTH CENTRAL WHERE SOUNDINGS INDICATE A WARM LAYER ALOFT...COLD LAYER AROUND 850MB...AND SURFACE TEMPERATURES IN THE MIDDLE 30S. THE WARM LAYER WILL COOL WITH ALL SNOW BY 01-02Z. HEADLINES ALL STILL VALID...AND WILL STAY THE COURSE WITH THIS UPDATE. UPDATE ISSUED AT 608 PM CDT SUN MAY 17 2015 OPTED TO ISSUE A HIGH WIND WARNING OVER ROLETTE AND PIERCE COUNTIES. WINDS CONTINUE TO GUST OVER 60 MPH AT OBSERVING SITES ACROSS MY FAR NORTHEAST. CANNOT IGNORE THIS SO WENT WITH A WARNING. OTHER EDITS MINOR FOR NOW...ANOTHER UPDATE OUT BY 0030Z. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 330 PM CDT SUN MAY 17 2015 SIGNIFICANT STORM IMPACTING NORTH DAKOTA WILL BEGIN TO WANE TONIGHT AND EXIT THE REGION ON MONDAY. AS COLDER AIR WRAPS UP INTO THE SYSTEM SNOW WILL START TO ACCUMULATE ACROSS THE NORTH CENTRAL...WITH 2 TO NEAR 6 INCHES EXPECTED. STRONG WINDS WILL CONTINUE THROUGH THE NIGHT. WILL KEEP WIND ADVISORY THROUGH 7 PM NORTH CENTRAL THEN TRANSITION TO A WINTER WEATHER ADVISORY FOR THE SNOW AND MENTION THE STRONG WINDS IN THE WINTER WEATHER ADVISORY. WILL MAINTAIN WIND ADVISORY THROUGH THE NIGHT SOUTH CENTRAL. THE RAIN WILL SIGNIFICANTLY DECREASE AFTER MIDNIGHT. UNTIL THEN THERE IS A FLOOD ADVISORY FOR EAST CENTRAL NORTH DAKOTA WHERE WIDESPREAD WARM CONVEYER BELT PRECIP HAS BEEN QUASI STATIONARY TODAY. FINALLY...WIDESPREAD FREEZING TEMPERATURES ARE EXPECTED ACROSS WEST AND CENTRAL NORTH DAKOTA TONIGHT. WILL LET THE WINTER WEATHER ADVISORY AND ITS SNOW AMOUNTS STAND IN FOR THE FREEZE WARNING NORTH CENTRAL. ACROSS THE WEST AND SOUTH WILL ISSUE A FREEZE WARNING TONIGHT AND EARLY MONDAY. MONDAY WILL BECOME SUNNY WITH DIMINISHING WINDS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 PM CDT SUN MAY 17 2015 COOL AND DRY WILL CHARACTERIZE THE LONG TERM. HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING WEEKEND STORM MONDAY NIGHT. THIS WILL LEAD TO CLEAR SKIES AND LIGHT WIND. TEMPERATURES OVERNIGHT WILL LIKELY FALL INTO THE MID 20S FOR MOST OF NORTH DAKOTA. A FREEZE WARNING WILL BE POSSIBLE WITH WIDESPREAD FROST. THE REST OF THE WEEK LOOKS DRY WITH SURFACE HIGH PRESSURE REMAINING ENTRENCHED OVER NORTH DAKOTA AND UPPER LEVEL RIDING BUILDING WEST. THIS WILL KEEP MOST OF THE MOISTURE AND STORM TRACKS THIS WEEK SOUTH OF NORTH DAKOTA. TEMPERATURES LOOK TO REBOUND INTO THE 60S BY THURSDAY. THE NEXT CHANCE FOR PRECIPITATION ARRIVES THIS WEEKEND AS THE RIDGE BREAKS DOWN AND AN UPPER LEVEL LOW MOVES INTO THE PLAINS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 1004 PM CDT SUN MAY 17 2015 WIDESPREAD IFR CONDITIONS IN RAIN AND SNOW WILL CONTINUE THROUGH TONIGHT. RAIN WILL CONTINUE TO TRANSITION TO ALL SNOW OVERNIGHT. CONDITIONS WILL IMPROVE NORTHWEST 04-07Z...ELSEWHERE WEST 08-12Z...AND ACROSS CENTRAL NORTH DAKOTA TOMORROW MORNING FROM WEST TO EAST. && .HYDROLOGY... ISSUED AT 330 PM CDT SUN MAY 17 2015 HAVE ISSUED AN AREAL FLOOD ADVISORY THROUGH THIS EVENING EAST CENTRAL. RAINFALL AMOUNTS OF TWO TO 4 INCHES WITH SOME ISOLATED HIGHER AMOUNTS CAUSING PONDING...AND FLOODED FIELDS. CALLS AND INQUIRIES SO FAR HAVE REVEALED ROADS TO BE OK WITH SOME MINOR FLOODING. && .BIS WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ MONDAY FOR NDZ001-009- 017>020-031>037-040>048-050-051. WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ MONDAY FOR NDZ019-020- 034>037-042-045>048-050-051. WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ002>005- 010>013-021>023-025. HIGH WIND WARNING UNTIL 1 AM CDT MONDAY FOR NDZ005-013. && $$ UPDATE...NH SHORT TERM...WAA LONG TERM...AJ AVIATION...NH HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 PM CDT SUN MAY 17 2015 .UPDATE... ISSUED AT 955 PM CDT SUN MAY 17 2015 RADAR INDICATES WHAT WAS TALKED ABOUT BELOW AND FEEL THE FORECAST IS WORKING OUT AS EXPECTED. WINDS NEAR THE INTERNATIONAL BORDER BY ROLLA...CANDO...AND LANGDON STILL NEAR OR INTO WARNING CRITERIA...BUT THE GENERAL TREND SHOULD BE SLOWLY DIMINISHING. UPDATE ISSUED AT 700 PM CDT SUN MAY 17 2015 GETTING REPORTS OF SLEET AND SNOW WITHIN THE DEFORMATION ZONE BAND OF PRECIP ACROSS THE DEVILS LAKE BASIN...AND DID INTRODUCE SLEET TO THE FORECAST. THIS PRECIP BAND WILL LIKELY START TO SLOWLY DISSIPATE AS THE MID-LEVEL LOW PROPAGATES INTO NORTHERN MINNESOTA (AND ANOTHER BAND OF PRECIP DEVELOPS EAST OF THE VALLEY). RAP/HRRR SUGGESTING THIS BAND OF PRECIP WILL REMAIN RELATIVELY STATIONARY THROUGH MIDNIGHT WHILE DISSIPATING. NOT SURE HOW MUCH SNOW WILL ACCUMULATE ON TOP OF THE WARM GROUND...BUT REDUCED VSBY WILL BE AN ISSUE. NEAR BLIZZARD CONDITIONS ALSO POSSIBLE IF THE P-TYPE CAN CHANGE TO ALL SNOWFALL (ALTHOUGH THESE CONDITIONS WOULD BE FOR LESS THAN 3 HOURS...SO A BLIZZARD WARNING IS NOT ANTICIPATED). WILL NOT MESS WITH POPS AT THIS POINT AS MOST AREAS SHOULD EXPERIENCE AT LEAST SOME PRECIP OVERNIGHT. HOWEVER...DID ADJUST QPF TO LOWER WITHIN THE MIDDLE AREA OF THE CURRENT DEF BAND ACROSS THE DVL BASIN AND WHERE THE NEXT DEF BAND IS EXPECTED TO DEVELOP. UPDATE ISSUED AT 610 PM CDT SUN MAY 17 2015 WILL NEED TO ISSUE A HIGH WIND WARNING ACROSS THE DEVILS LAKE BASIN FOR THIS EVENING. OBSERVATIONS OF SUSTAINED 40 MPH...AND GUSTS TO 60 MPH ARE BECOMING MORE WIDESPREAD. THERE HAS ALSO BEEN A REPORT OF DOWNED TREES IN BOTTINEAU...AND LARGER TREE BRANCHES DOWN IN DEVILS LAKE. THE LATEST RAP SUGGESTS THE SFC PRESSURE GRADIENT WILL SLIGHTLY INCREASE THROUGH 03Z...WITH 925MB AND 850MB WIND SPEEDS SLIGHTLY INCREASING. THUS...STRONG WINDS WITH THE POTENTIAL TO CAUSE DAMAGE WILL CONTINUE FOR AT LEAST A FEW MORE HOURS. WILL KEEP THE WINTER WX ADVISORY IN EFFECT WITH REPORTS THAT THE PRECIP IS BEGINNING TO CHANGEOVER TO SLEET/SNOW...AND ANTICIPATE WINTRY WEATHER THIS EVENING AND OVERNIGHT. OF COURSE...IF THE PRECIP BECOMES ALL SNOW THEN BLIZZARD CONDITIONS MAY BE POSSIBLE...BUT LIKELY FOR LESS THAN 3 HOURS. WILL MONITOR THE SITUATION CLOSELY. ELSEWHERE...THE THREAT FOR TORNADOES ACROSS NW MN APPEARS TO HAVE DIMINISHED AS THE WARM SECTOR IS PROPAGATING EASTWARD. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 337 PM CDT SUN MAY 17 2015 FIRST OFF...SFC LOW NEAR SISSETON/WAHPETON AREA AT MID AFTN AND SFC PRESSURE FALLS ARE NOT CENTERED NEAR FOSSTON MN. SO SFC LOW WILL TACK NORTHEAST TOWARD THAT AREA THIS EVENING. EAST OF SFC LOW AREA IN DRY SLOT WHERE HEATING OCCURRED FAVORABLE FOR SOME THUNDERSTORM TO FORM. FOCUS IS FROM ALEXANDRIA NORTH TO EAST OF FERGUS FALLS....TO BEMIDJI...PARK RAPIDS AND WADENA. SFC AND UPPER AIR LOW PLACEMENT FAVORS LOW TOPPED SUPERCELLS WITH POSSIBLE FUNNEL FORMATION. PER SPC NOT EXPECTING WIDESPREAD STORMS THIS STRONG....BUT COULD BE THRU 00Z. ANOTHER QUESTION IS NW EDGE OF DEF ZONE PRECIP. RAIN FALLING PER PUBLIC LANGDON-DEVILS LAKE AREA STILL. MODELS TAKE DRIER AIR WEST AND WANT TO SHUT OFF DEF ZONE HEAVY PRECIP THIS EVENING LEAVING LIGHT PRECIP OVERNIGHT INTO MONDAY MORNING IN THE COLD AIR WHERE IT WILL BE COLD ENOUGH FOR SNOW. SO JUST HOW MUCH SNOW WILL FALL IS QUESTIONABLE. WILL LEAVE WSW OUT FOR 1-3 INCHES IN DVL BASIN-LANGDON AREAS OVERNIGHT AS TOO UNCERTAIN TO TINKER WITH IT. WINDS WILL BE A BIG FACTOR AND CONTINUE TO GUST IN THE 40-55 MPH RANGE IN DVL BASIN AND SPREAD INTO THE RRV THIS EVE. STRONG WINDS OVERNIGHT INTO MONDAY MORNING SO HAVE WIND ADVISORIES OUT. MOVED PRECIP OUT A BIT FASTER THAN EARLIER FCSTS MONDAY. OTHERWISE COLD AND WINDY. CLEARING OVERSPREADS AREA MON NIGHT AND LIKELY FREEZE CONDITIONS IN MANY AREAS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 337 PM CDT SUN MAY 17 2015 WELCOME DRY WEATHER TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES IN AND TEMPS BEGIN TO RECOVER. FOR WED NIGHT THROUGH SUNDAY...SMALL DISCUSSION TODAY DUE TO SEVERE WEATHER POTENTIAL. BASICALLY KEPT THE THU/FRI PERIOD DRY AND LEFT PCPN CHANCES AS THEY WERE FOR SAT/SUN. TEMPS LOOK TO RETURN TO NEAR NORMAL VALUES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 700 PM CDT SUN MAY 17 2015 IFR/LIFR CONDITIONS EXPECTED INTO MONDAY...WITH GRADUALLY IMPROVING CONDITIONS ON MONDAY. STRONG NORTH WINDS ALONG AND WEST OF THE VALLEY OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ008-016-026>030-038- 039-049-052>054. HIGH WIND WARNING UNTIL 11 PM CDT THIS EVENING FOR NDZ006-007- 014-015. WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ006-007-014- 015-024. MN...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ001>004-007-029. && $$ UPDATE...TG SHORT TERM...RIDDLE LONG TERM...GODON/RIDDLE AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
610 PM CDT SUN MAY 17 2015 .UPDATE... ISSUED AT 610 PM CDT SUN MAY 17 2015 WILL NEED TO ISSUE A HIGH WIND WARNING ACROSS THE DEVILS LAKE BASIN FOR THIS EVENING. OBSERVATIONS OF SUSTAINED 40 MPH...AND GUSTS TO 60 MPH ARE BECOMING MORE WIDESPREAD. THERE HAS ALSO BEEN A REPORT OF DOWNED TREES IN BOTTINEAU...AND LARGER TREE BRANCHES DOWN IN DEVILS LAKE. THE LATEST RAP SUGGESTS THE SFC PRESSURE GRADIENT WILL SLIGHTLY INCREASE THROUGH 03Z...WITH 925MB AND 850MB WIND SPEEDS SLIGHTLY INCREASING. THUS...STRONG WINDS WITH THE POTENTIAL TO CAUSE DAMAGE WILL CONTINUE FOR AT LEAST A FEW MORE HOURS. WILL KEEP THE WINTER WX ADVISORY IN EFFECT WITH REPORTS THAT THE PRECIP IS BEGINNING TO CHANGEOVER TO SLEET/SNOW...AND ANTICIPATE WINTRY WEATHER THIS EVENING AND OVERNIGHT. OF COURSE...IF THE PRECIP BECOMES ALL SNOW THEN BLIZZARD CONDITIONS MAY BE POSSIBLE...BUT LIKELY FOR LESS THAN 3 HOURS. WILL MONITOR THE SITUATION CLOSELY. ELSEWHERE...THE THREAT FOR TORNADOES ACROSS NW MN APPEARS TO HAVE DIMINISHED AS THE WARM SECTOR IS PROPAGATING EASTWARD. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 337 PM CDT SUN MAY 17 2015 FIRST OFF...SFC LOW NEAR SISSETON/WAHPETON AREA AT MID AFTN AND SFC PRESSURE FALLS ARE NOT CENTERED NEAR FOSSTON MN. SO SFC LOW WILL TACK NORTHEAST TOWARD THAT AREA THIS EVENING. EAST OF SFC LOW AREA IN DRY SLOT WHERE HEATING OCCURRED FAVORABLE FOR SOME THUNDERSTORM TO FORM. FOCUS IS FROM ALEXANDRIA NORTH TO EAST OF FERGUS FALLS....TO BEMIDJI...PARK RAPIDS AND WADENA. SFC AND UPPER AIR LOW PLACEMENT FAVORS LOW TOPPED SUPERCELLS WITH POSSIBLE FUNNEL FORMATION. PER SPC NOT EXPECTING WIDESPREAD STORMS THIS STRONG....BUT COULD BE THRU 00Z. ANOTHER QUESTION IS NW EDGE OF DEF ZONE PRECIP. RAIN FALLING PER PUBLIC LANGDON-DEVILS LAKE AREA STILL. MODELS TAKE DRIER AIR WEST AND WANT TO SHUT OFF DEF ZONE HEAVY PRECIP THIS EVENIGN LEAVING LIGHT PRECIP OVERNIGHT INTO MONDAY MORNING IN THE COLD AIR WHERE IT WILL BE COLD ENOUGH FOR SNOW. SO JUST HOW MUCH SNOW WILL FALL IS QUESTIONABLE. WILL LEAVE WSW OUT FOR 1-3 INCHES IN DVL BASIN-LANGDON AREAS OVERNIGHT AS TOO UNCERTAIN TO TINKER WITH IT. WINDS WILL BE A BIG FACTOR AND CONTINUE TO GUST IN THE 40-55 MPH RANGE IN DVL BASIN AND SPREAD INTO THE RRV THIS EVE. STRONG WINDS OVERNIGHT INTO MONDAY MORNING SO HAVE WIND ADVISORIES OUT. MOVED PRECIP OUT A BIT FASTER THAN EARLIER FCSTS MONDAY. OTHERWISE COLD AND WINDY. CLEARING OVERSPREADS AREA MON NIGHT AND LIKELY FREEZE CONDITIONS IN MANY AREAS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 337 PM CDT SUN MAY 17 2015 WELCOME DRY WEATHER TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES IN AND TEMPS BEGIN TO RECOVER. FOR WED NIGHT THROUGH SUNDAY...SMALL DISCUSSION TODAY DUE TO SEVERE WEATHER POTENTIAL. BASICALLY KEPT THE THU/FRI PERIOD DRY AND LEFT PCPN CHANCES AS THEY WERE FOR SAT/SUN. TEMPS LOOK TO RETURN TO NEAR NORMAL VALUES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 107 PM CDT SUN MAY 17 2015 LOT OF ELEMENTS TO COVER IN THE TAFS FOR THE NEXT 24 HOURS. FIRST OF ALL TSTM CHANCES. HAVE SOME THINNING OF THE CLOUDS ACROSS WEST CENTRAL MN WHICH COULD POSSIBLY LEAD TO SOME THUNDER YET AT KBJI. OTHERWISE OTHER TAF LOCATIONS LOOK TO BE TOO FAR WEST. MAIN AREA OF PCPN APPEARS TO BE PINWHEELING BACK TO THE NW AND MAY GIVE ALL TAF SITES BUT KDVL A LITTLE BREAK FROM THE STEADY PCPN. EVEN IF IT DOES GIVE A BREAK IT SHOULD SLIDE BACK TO THE EAST LATER...BUT MAYBE WITH NOT QUITE SO HEAVY OF PCPN. WINDS WILL REALLY HOWL AT KDVL/KGFK FOR THE NEXT 24 HOURS AND WILL EVENTUALLY SPREAD TO KFAR/KTVF AND FINALLY KBJI LATER. TEMPS PLUNGE BEHIND THE SYSTEM SO THERE WILL BE A SWITCH TO RAIN/SNOW THEN ALL SNOW TONIGHT. QUESTION IS STILL HOW MUCH THE VSBY WILL BE RESTRICTED BY ANY SNOW...AND DO NOT HAVE A GOOD IDEA AT THE MOMENT. TAFS WILL HAVE TO BE UPDATED FREQUENTLY I AM SURE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ008-016-026>030-038- 049-052-054. WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ039-053. HIGH WIND WARNING UNTIL 11 PM CDT THIS EVENING FOR NDZ006-007- 014-015. WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ006-007-014- 015-024. WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ024. MN...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ001-004-007. WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ002-003-029. && $$ UPDATE...TG SHORT TERM...RIDDLE LONG TERM...GODON/RIDDLE AVIATION...GODON
AREA FORECAST DISCUSSION
NWS BISMARCK ND
339 PM CDT SAT MAY 16 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 340 PM CDT SAT MAY 16 2015 CONCERNS THIS FORECAST PERIOD INCLUDE SEVERE WEATHER POSSIBILITY AND HEAVY RAIN. BY THE END OF THE SHORT TERM THE TRANSITION TO MUCH COOLER WEATHER WITH SOME SNOW BEGINS TO BE SEEN. AT 230 PM CDT...SURFACE LOW PRESSURE WAS CENTERED NEAR NORTHWEST SOUTH DAKOTA WITH AN EAST WEST WARM FRONTAL BOUNDARY EXTENDED ACROSS NORTH CENTRAL SOUTH DAKOTA. FLOW OVER THE WARM FRONT WAS GENERATING SHOWERS AND SCATTERED THUNDERSTORMS FROM MOBRIDGE NORTH TO NEAR MINOT AND NORTH TO THE CANADIAN BORDER. CONCERNING SEVERE WEATHER POTENTIAL...AN 18Z KBIS SOUNDINGS WAS CONDUCTED. HRRR FORECAST CAPE VALUES IN THE NEIGHBORHOOD OF 2000 ARE FORECAST TO POOL ACROSS SOUTH CENTRAL INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND EVENING. EXPECT THE SEVERE WEATHER POTENTIAL TO EXTEND FROM BISMARCK EAST. TO THE WEST EXPECT MORE ELEVATED THUNDERSTORMS. LATE TONIGHT AND SUNDAY...AN UPPER LEVEL LOW SWINGS INTO EASTERN SOUTH DAKOTA THEN TRACKS NORTHEAST AND SPREADS A LARGE AREA OF THE RAINSHOWERS ACROSS THE EAST HALF OF THE STATE AND ESPECIALLY THE JAMES RIVER VALLEY. ACROSS THE NORTH CENTRAL...COOLER AIR WILL BEGIN A RAIN/SNOW CHANGE OVER. AS THE SURFACE LOW WRAPS UP NORTH WINDS OF 25 TO 35 MPH WILL BE COMMON ACROSS CENTRAL NORTH DAKOTA ON SUNDAY. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 340 PM CDT SAT MAY 16 2015 RAIN...SNOW AND COLD TEMPERATURES WILL HIGHLIGHT THE LONG TERM. THE STORM IMPACTING NORTH DAKOTA SATURDAY AND SUNDAY WILL CONTINUE TO INFLUENCE THE REGION THROUGH MONDAY. THE UPPER LEVEL LOW AND SURFACE LOW WILL BECOME NEARLY VERTICALLY STACKED OVER EASTERN NORTH DAKOTA SUNDAY NIGHT. THIS WILL LEAD TO ENHANCED LIFT AND PRECIPITATION ACROSS PORTIONS OF CENTRAL AND EASTERN NORTH DAKOTA. AS THE LOW PROPAGATES EASTWARD SUNDAY NIGHT INTO MONDAY...COLD AIR WILL WRAP IN FROM THE NORTH. A STEADY RAIN WILL TRANSITION TO SNOW FROM NORTHWEST TO SOUTHEAST SUNDAY NIGHT. IN ADDITION TO TRANSITIONING RAIN TO SNOW...STRONG COLD AIR ADVECTION AND A STEEP PRESSURE GRADIENT WILL PRODUCE GUSTY NORTHWEST WINDS AROUND 35 MPH. THE 12 UTC GFS/ECMWF/SREF/GEM ARE IN GOOD AGREEMENT WITH RESPECT TO PRECIPITATION AMOUNTS AND TEMPERATURES. THEREFORE...UTILIZED A BLEND OF THE OPERATIONAL MODELS. THIS GENERALLY YIELDED LIQUID PRECIPITATION AMOUNTS AROUND HALF AN INCH AND SNOW AMOUNTS AROUND 1 OR 2 INCHES SUNDAY NIGHT INTO MONDAY. WITH TEMPERATURES HOVERING NEAR FREEZING...ROAD TEMPERATURES COULD BE WARM ENOUGH TO LIMIT NEGATIVE IMPACTS TO TRAVEL. FROST AND TEMPERATURES IN THE 20S AND LOW 30S ARE LIKELY SUNDAY NIGHT AND MONDAY NIGHT. FOR NORTH DAKOTA THE REST OF THE LONG TERM APPEARS COOL AND DRY...WITH FREQUENT RAIN CHANCES ACROSS SOUTH DAKOTA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 340 PM CDT SAT MAY 16 2015 AT 230 PM CDT A WARM FRONT EXTENDED FROM A SURFACE LOW PRESSURE CENTERED OVER NORTHWEST SOUTH DAKOTA WITH AN EAST WEST WARM FRONT EXTENDING EAST ACROSS NORTH CENTRAL SOUTH DAKOTA. MOIST FLOW OVER THE FRONT WILL MAINTAIN WIDESPREAD IFR KISN- KDIK-KBIS-KMOT WITH MVFR CONDITIONS KJMS. THUNDERSTORMS WILL BECOME MORE NUMEROUS LATE SATURDAY AFTERNOON AND EVENING EAST OF KBIS- KMOT LINE. && .HYDROLOGY... ISSUED AT 340 PM CDT SAT MAY 16 2015 FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN ONE AND TWO INCHES. CONFIDENCE IS LOW REGARDING TIMING AND PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...WAA LONG TERM...AJ AVIATION...WAA HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1248 PM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 1239 PM CDT SAT MAY 16 2015 LAUNCHED AN 18Z SOUNDING IN SUPPORT OF THE SEVERE WEATHER OPERATIONS THIS AFTERNOON AND EVENING. AT 1230 CDT A WARM FRONT EXTENDED FROM A LOW IN SOUTHEAST MONTANA EAST THROUGH NORTH CENTRAL SOUTH DAKOTA. FOCUSED THE HIGHEST POPS WEST CENTRAL INTO THE NORTH WHERE BEST OVER RUNNING FLOW OVER THE WARM FRONT CURRENTLY IS SPAWNING SHOWERS AND A FEW THUNDERSTORMS. RIGHT NOW THE ACTIVITY IS ELEVATED WAND WEAK. WILL BE ANTICIPATING FURTHER DEVELOPMENT NEXT FEW HOURS INTO THE EVENING CENTRAL MOVING INTO THE JAMES RIVER VALLEY THIS EVENING. UPDATE ISSUED AT 923 AM CDT SAT MAY 16 2015 VERY MOIST BOUNDARY LAYER AFTER OVERNIGHT RAINS. ACROSS THE SOUTHWEST A SOUTHEAST UPSLOPE FLOW HAS RESULTED IN AREAS OF FOG AND LOW CLOUDS. WILL ADD THIS TO THE FOREST THROUGH NOON. ELEVATED CONVECTION ONGOING OVER THE LOW LEVELS SOUTHWEST SO KEPT A SLIGHT CHANCE OF THUNDERSTORMS THERE. HOWEVER...DROPPED THE MENTION OF THUNDERSTORMS THIS MORNING NORTH AND EAST BASED ON LATEST HRRR CAPE FORECAST WHICH BASICALLY HOLDS OF THE THREAT OF THUNDER TIL THIS AFTERNOON. UPDATE ISSUED AT 615 AM CDT SAT MAY 16 2015 AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN RAPID CITY AND ABERDEEN SOUTH DAKOTA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM CDT SAT MAY 16 2015 MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT. THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD. THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY OVER CENTRAL NORTH DAKOTA. TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5 INCH TO 1.25 INCHES. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 445 AM CDT SAT MAY 16 2015 NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS POINTS OVER THE NEXT SEVERAL DAYS. FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S. AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR. COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8 TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES. EVEN UNDER CLOUD COVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG NORTHWEST WINDS CONTINUE. WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN THE 27 TO 34 DEGREE RANGE. BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1239 PM CDT SAT MAY 16 2015 AT 1230 PM CDT A WARM FRONT EXTENDED FROM A SURFACE LOW PRESSURE CENTERED OVER SOUTHEAST MONTANA WITH A WARM FRONT EXTENDING EAST ACROSS NORTH CENTRAL SOUTH DAKOTA. MOIST FLOW OVER THE FRONT WILL MAINTAIN WIDESPREAD IFR KISN- KDIK-KBIS WITH MVFR CONDITIONS KMOT- KJMS. CONDITIONS GENERALLY BECOMING MVFR LATE SATURDAY AFTERNOON. THUNDERSTORMS WILL BECOME MORE NUMEROUS LATE SATURDAY AFTERNOON AND EVENING EAST OF KBIS-KMOT LINE. && .HYDROLOGY... ISSUED AT 445 AM CDT SAT MAY 16 2015 FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...JV LONG TERM...JPM AVIATION...WAA HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
936 AM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 923 AM CDT SAT MAY 16 2015 VERY MOIST BOUNDARY LAYER AFTER OVERNIGHT RAINS. ACROSS THE SOUTHWEST A SOUTHEAST UPSLOPE FLOW HAS RESULTED IN AREAS OF FOG AND LOW CLOUDS. WILL ADD THIS TO THE FOREST THROUGH NOON. ELEVATED CONVECTION ONGOING OVER THE LOW LEVELS SOUTHWEST SO KEPT A SLIGHT CHANCE OF THUNDERSTORMS THERE. HOWEVER...DROPPED THE MENTION OF THUNDERSTORMS THIS MORNING NORTH AND EAST BASED ON LATEST HRRR CAPE FORECAST WHICH BASICALLY HOLDS OF THE THREAT OF THUNDER TIL THIS AFTERNOON. UPDATE ISSUED AT 615 AM CDT SAT MAY 16 2015 AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN RAPID CITY AND ABERDEEN SOUTH DAKOTA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM CDT SAT MAY 16 2015 MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT. THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD. THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY OVER CENTRAL NORTH DAKOTA. TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5 INCH TO 1.25 INCHES. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 445 AM CDT SAT MAY 16 2015 NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS POINTS OVER THE NEXT SEVERAL DAYS. FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S. AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR. COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8 TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES. EVEN UNDER CLOUD COVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG NORTHWEST WINDS CONTINUE. WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN THE 27 TO 34 DEGREE RANGE. BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 923 AM CDT SAT MAY 16 2015 AT 930 AM CDT A SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHEAST MONTANA WITH A WARM FRONT EXTENDED EAST ACROSS CENTRAL SOUTH DAKOTA. MOIST FLOW OVER THE FRONT WILL MAINTAIN WIDESPREAD IFR KISN- KDIK-KBIS WITH MVFR CONDITIONS KMOT-KJMS THROUGH NOON. LOW LEVEL UPSLOPE FLOW ACROSS THE SOUTHWEST WILL RESULT IN VERY LOW IFR CONDITIONS IN FOG AT KDIK THROUGH 17Z. CONDITIONS GENERALLY BECOMING MVFR SATURDAY AFTERNOON. THUNDERSTORMS WILL BECOME MORE NUMEROUS LATE SATURDAY AFTERNOON AND EVENING EAST OF KBIS-KMOT LINE. && .HYDROLOGY... ISSUED AT 445 AM CDT SAT MAY 16 2015 FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...JV LONG TERM...JPM AVIATION...WAA HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
623 AM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 615 AM CDT SAT MAY 16 2015 AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN RAPID CITY AND ABERDEEN SOUTH DAKOTA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM CDT SAT MAY 16 2015 MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT. THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD. THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY OVER CENTRAL NORTH DAKOTA. TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5 INCH TO 1.25 INCHES. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 445 AM CDT SAT MAY 16 2015 NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS POINTS OVER THE NEXT SEVERAL DAYS. FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S. AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR. COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8 TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES. EVEN UNDER CLOUDCOVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG NORTHWEST WINDS CONTINUE. WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN THE 27 TO 34 DEGREE RANGE. BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 615 AM CDT SAT MAY 16 2015 THE MAIN CONCERN IS THE SHOWER / THUNDERSTORM CHANCES AND THE ASSOCIATED MVFR CEILINGS / VISIBILITIES. EXPECT INCREASING CHANCES FOR SHOWERS THROUGH THE DAY...WITH INCREASING CHANCES FOR THUNDERSTORMS ESPECIALLY CENTRAL AND EASTERN NORTH DAKOTA TAF SITES. AFTER 03Z ON THE 17TH THUNDER CHANCES WILL DECREASE AS WIDESPREAD RAIN MOVES IN WITH MVFR CONDITIONS. && .HYDROLOGY... ISSUED AT 445 AM CDT SAT MAY 16 2015 FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JPM SHORT TERM...JV LONG TERM...JPM AVIATION...JV/JPM HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
455 AM CDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM CDT SAT MAY 16 2015 MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT. THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD. THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY OVER CENTRAL NORTH DAKOTA. TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5 INCH TO 1.25 INCHES. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 445 AM CDT SAT MAY 16 2015 NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS POINTS OVER THE NEXT SEVERAL DAYS. FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S. AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR. COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8 TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES. EVEN UNDER CLOUDCOVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG NORTHWEST WINDS CONTINUE. WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN THE 27 TO 34 DEGREE RANGE. BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 445 AM CDT SAT MAY 16 2015 THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN WILL LIFT NORTH BRINGING A CHANCE OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS TO THE TERMINALS THIS MORNING. CEILINGS WILL LOWER AS THE RAIN MOVES INTO THE REGION. THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN SATURDAY AFTERNOON AND NIGHT. CHANCES ARE BETTER SATURDAY AFTERNOON AND EVENING FOR THUNDER. && .HYDROLOGY... ISSUED AT 445 AM CDT SAT MAY 16 2015 FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JV LONG TERM...JPM AVIATION...JV HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
115 AM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 114 AM CDT SAT MAY 16 2015 MAIN UPDATE TO THE FORECAST WAS TO SLOW THE ONSET OF PRECIPITATION IN THE SOUTHWEST. THOUGH IT IS RAINING IN HETTINGER...THE LEADING EDGE OF RAIN SHOWERS HAD NOT YET REACHED DICKINSON OR GRANT OR SIOUX COUNTY. THE LATEST HRRR MODEL WAS HANDLING THE CURRENT PRECIPITATION AREA WELL...SO BACKED OFF ON PRECIP CHANCES NORTH AND EAST FOR EARLY THIS MORNING AND INCREASED CHANCES AFTER AROUND 3 AM CDT. OTHERWISE FORECAST ON TRACK FOR THE OVERNIGHT HOURS. UPDATE ISSUED AT 946 PM CDT FRI MAY 15 2015 MAIN UPDATE TO THE FORECAST THIS EVENING WAS TO SPREAD THE POSSIBILITY OF ISOLATED THUNDERSTORMS INTO THE WESTERN PART OF THE STATE. FORECAST MUCAPE FROM THE RAP SHOWS WEAK INSTABILITY FROM WESTERN INTO SOUTH CENTRAL NORTH DAKOTA OVERNIGHT. CURRENT RADAR MOSAIC INDICATES SHOWERS AND THUNDERSTORMS IN WESTERN SOUTH DAKOTA CONTINUE TO MOVE NORTH...WHICH IS WELL COVERED IN THE FORECAST WITH HIGH POPS IN PLACE OVERNIGHT. DECIDED TO ISSUE THE SPECIAL WEATHER STATEMENT (SPS) AGAIN TO HIGHLIGHT THE ACTIVE WEATHER IN THE FORECAST FOR THIS WEEKEND. UPDATE ISSUED AT 645 PM CDT FRI MAY 15 2015 REGIONAL RADAR MOSAIC SHOWERS A FEW LIGHT SHOWERS MOVING ACROSS WESTERN NORTH DAKOTA INTO EASTERN MONTANA. FARTHER SOUTH...THUNDERSTORMS WERE LIFTING NORTH ACROSS PARTS OF WESTERN SOUTH DAKOTA. THE LATEST HRRR AND RAP SUGGEST IT WILL TAKE A FEW MORE HOURS BEFORE THE MAIN AREA OF RAIN IN SOUTH DAKOTA REACHES THE SOUTHWEST PART OF THE STATE. THE HRRR ALSO SUGGESTS THERE COULD BE A FEW ISOLATED SHOWERS IN ADVANCE OF THE MAIN AREA OF RAIN...SO DID NOT REMOVE POPS ALTOGETHER IN THE NEAR TERM...BUT DID DECREASE THEM TO SOME DEGREE EARLY THIS EVENING. MADE MINOR ADJUSTMENTS TO SKY COVER AND TEMPERATURES...BUT OVERALL THE REMAINDER OF THE FORECAST LOOKS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 303 PM CDT FRI MAY 15 2015 MAIN ISSUES IN THE SHORT TERM ARE TIMING THE START OF PRECIPITATION THIS EVENING AND POSSIBLE SEVERE THUNDERSTORMS SATURDAY. MODELS AND RADAR SHOWING SLOWER TRENDS OF PRECIPITATION SO WILL DELAY THE ONSET OF PRECIP ACROSS THE SOUTH CENTRAL AND JAMES RIVER VALLEY TO MID TO LATE EVENING. NAM/GFS BOTH HAVE A FAIRLY GOOD CAP LOWER LEVELS. THERE IS SOME ELEVATED CAPE THIS EVENING AND OVERNIGHT SO REFINED THE THREAT OF NON SEVERE THUNDERSTORMS TONIGHT TO JUST THE SOUTH CENTRAL AND AFTER 9 PM CDT. ON SATURDAY LOOKING FRO A MORE SIGNIFICANT SHORTWAVE TROUGH SUPPORTING THUNDERSTORMS. BEST CAPE REMAINS SOUTH CENTRAL WITH THE JAMES RIVER VALLEY MORE CAPPED TRENDING TO TALL SKINNY CAPE BY EVENING. THIS WOULD LEND LESS SUPPORT TO SEVERE MORE TO MODERATE RAIN. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 303 PM CDT FRI MAY 15 2015 VERY ACTIVE WEATHER WILL OCCUR OVER THE WEEKEND WITH NUMEROUS IMPACTS AS A STRONG STORM SYSTEM CROSSES THE NORTHERN PLAINS. INITIALLY...SEVERE THUNDERSTORMS WILL BE THE THREAT SATURDAY EVENING...THOUGH SURFACE BASED INSTABILITY WILL DIMINISH WHILE PROFILES SATURATE PER FORECAST SOUNDINGS. MEANWHILE A STRONG 100KT JET WILL BEGIN NOSING INTO THE DAKOTAS AND HELP DEEPEN THE CUT OFF UPPER LOW WHICH IS LOCATED OVER SOUTH DAKOTA AT 12Z SUNDAY. DEEP SURFACE LOW REACHES SOUTHEASTERN NORTH DAKOTA BY 00Z MON WITH STRONG SURFACE PRESSURE GRADIENT ACROSS THE STATE...26MB CHANGE FROM NORTHWEST ND TO THE SOUTHEAST PART OF THE STATE PER GFS. SUB- FREEZING 850MB TEMPS DROP SOUTHWARD INTO CENTRAL NORTH DAKOTA...WITH SOUNDINGS SUPPORTING A CHANGEOVER OF RAIN TO SNOW LATE SUNDAY/SUNDAY NIGHT. WPC WINTER WEATHER DESK SHOWS AMOUNTS AROUND 2-4 INCHES ACROSS THE NORTH. TRAVEL COULD BECOME HAZARDOUS IN SOME AREAS WITH COMBINATION OF STRONG WIND AND SNOW. BY MID-DAY MONDAY THE LOW CENTER REACHES THE GREAT LAKES WITH HIGH PRESSURE BUILDING ACROSS THE STATE. MAX TEMPS WILL GRADUALLY MODERATE TO THE 50S AND 60S BY WED/THU. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 114 AM CDT SAT MAY 16 2015 THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN ACROSS SOUTH DAKOTA WILL LIFT NORTH BRINGING A CHANCE OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS TO THE TERMINALS THIS MORNING. CEILINGS WILL LOWER AS THE RAIN MOVES INTO THE REGION. THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN SATURDAY AFTERNOON AND NIGHT. CHANCES ARE BETTER SATURDAY AFTERNOON AND EVENING FOR THUNDER. && .HYDROLOGY... ISSUED AT 303 PM CDT FRI MAY 15 2015 ENSEMBLE SITUATIONAL AWARENESS TABLE SHOWS PRECIPITABLE WATER OVER OUR AREA AROUND 90TH PERCENTILE FROM SATURDAY INTO SUNDAY AFTERNOON. FORECAST PRECIP AMOUNTS THROUGH 00Z MONDAY RANGE FROM AROUND 0.75 INCHES OVER SOUTHWESTERN ND TO 2+ INCHES...MAINLY NORTH AND EAST. CONTEMPLATED AN AREAL FLOOD WATCH...BUT THE HEAVIEST QPF AMOUNTS WITH THIS STORM ARE GENERALLY NORTH AND EAST OF THE AREAS THAT HAVE RECEIVED THE HEAVIEST PRECIPITATION OVER THE PAST COUPLE WEEKS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...WAA LONG TERM...JNS AVIATION...JV HYDROLOGY...WAA/JNS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
237 PM EDT SAT MAY 16 2015 .SYNOPSIS... WEAK MID/UPPER LEVEL DISTURBANCES...INCREASED MOISTURE AND INSTABILITY RESULTS IN ROUNDS OF SHOWERS/THUNDERSTORMS INTO EARLY NEXT WEEK. COLD FRONT PUSHES EAST TUESDAY. DRIER WEDNESDAY. && .NEAR TERM /THROUGH SUNDAY/... STILL HIGHLIGHTING THE RAIN...OVER ANY CONVECTIVE SEVERE THREAT FOR LARGE HAIL AND DAMAGING WINDS. THINKING WE COULD HAVE SOME EFFICIENT RAIN MAKERS/DUMPERS NEXT 24 HOURS...AS PRECIPITABLE WATER INCREASES TOWARD 1.7 INCHES. PLUS...WE HAVE WEAK MID/UPPER LEVEL DISTURBANCES TRYING TO RIDE UP AND OVER THE STUBBORN SE 500 MB RIDGE. OF COURSE...MOST COUNTIES NEED THE RAIN. PLUS...WE HAVE OUR BIG CONSUMER NOW WORKING HARD...THAT BEING THE FRESH SPRING VEGETATION. YET...WE DO NOT WANT TOO MUCH OF A GOOD THING. JUST MENTIONED IN THE HAZARDOUS WEATHER POTENTIAL ABOUT SOME PROGRESSIVE LOCALIZED DOWNPOURS. WE JUST HAVE TO WATCH FOR ANY REPETITIVE ACTION. THAT BEING SAID...THE VORT MAX WE DISCUSSED IN THE MORNING UPDATED AFD...LIFTED THROUGH NORTH CENTRAL WV ON SCHEDULE AROUND 17Z. A FEW SPOTS GOT A HALF INCH OF RAIN...MOST GOT MUCH LESS. MOST OF THAT ENERGY AT 1830Z WAS TRANSFERRING EAST OF US...TOWARD SOUTH CENTRAL PENNSYLVANIA AND FAR EASTERN WV PANHANDLE. NEXT VORT MAX ON RAP MOVES OUT OF KENTUCKY AND TOWARD MID OHIO VALLEY AND PKB BY 01Z SUNDAY. SO MENTIONED SOME LOCALIZED DOWNPOURS ASSOCIATED WITH IT...ACROSS OUR WESTERN COUNTIES. MOST MODEL SOLUTIONS SHOW ANOTHER 500 MB DISTURBANCE LATE TONIGHT FROM 06Z TO 12Z SUNDAY...RIDGING THROUGH SE OHIO THEN ACROSS NORTHERN WV SUNDAY MORNING. SO OF COURSE...HAD TO LEAVE POPS THROUGH THE NIGHT...HIGHEST IN THE WEST AND NORTH...LOWEST IN THE SOUTH AND EAST. NO BIG CHANGES PICTURED FOR SUNDAY...THROUGH THE HIGHER POPS MAY TRANSFER TO THE MOUNTAINS SUNDAY AFTERNOON...BEFORE TRANSFERRING BACK WEST AGAIN. FIGURING MAXIMUM TEMPERATURES REMAIN A HEADACHE...JUST DEPENDING ON THE BREAKS IN THE CLOUDS AND TIMING OF THE SHOWERS. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS NOTED BY PREVIOUS SHIFT...MODELS HAVE SLOWED DOWN COLD FRONT PASSAGE UNTIL TUESDAY. MAIN CHANGES THIS FORECAST PACKAGE WERE TO INCREASE POPS SOME ON TUESDAY AND ALSO TRY TO A THIN LINE OF HIGHER POPS ALONG THE FRONT AS IT MOVES THROUGH ON TUESDAY. HAVE THE HIGHEST POPS ACROSS THE EAST...AS THE FRONT WILL BE CROSSING THERE DURING THE AFTERNOON. WITH THE DELAYED FROPA...ALSO RAISED TEMPERATURES A BIT MONDAY NIGHT AND TUESDAY. OUTSIDE OF THESE CHANGES...MAINTAINED LIKELY POPS ON MONDAY IN THE WARM SECTOR. PRECIPITABLE WATER VALUES ON MONDAY WILL BE AROUND 1.75 INCHES. THIS WILL LIKELY PRODUCE POCKETS OF HEAVY RAIN IN AREAS OF HEALTHY CONVECTION. STORMS SHOULD MAINLY BE SCATTERED IN NATURE...WITH LITTLE SYNOPTIC ORGANIZATIONAL FORCING...SO WILL JUST HAVE TO WATCH FOR AREAS THAT MAY RECEIVE REPETITIVE BURSTS AS THE DAY GOES ON. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... NO REAL SIGNIFICANT WEATHER MAKERS IN THE LONG TERM PATTERN. THE PERIOD WILL START OUT ON THE NEAR NORMAL TO COOL SIDE IN THE WAKE OF TUESDAYS COLD FRONT. GFS/ECMWF BOTH SHOW A SURFACE HIGH SLOWLY MARCHING ACROSS THE NORTHERN PLAINS FOR THE LATTER HALF OF THE WEEK INTO THE WEEKEND. ANY PRECIPITATION SHOULD BE TIED TO 500MB RIPPLES WORKING THROUGH THE FAIRLY ZONAL FLOW. HAVE SOME SLIGHT CHANCE POPS ACROSS THE HIGHER TERRAIN THURSDAY AND FRIDAY AFTERNOON...BUT CONFIDENCE ON THIS IS RATHER LOW AT THIS POINT. TEMPERATURES WILL BE BACK UP TO NEAR AND ABOVE NORMAL BY THE END OF THE WEEK. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... HIGHLY VARIABLE CONDITIONS IN ROUNDS OF SHOWERS AND THUNDERSTORMS. THINKING THE CONVECTION MOST WIDESPREAD IN THE WESTERN LOWLANDS INCLUDING SOUTHEAST OHIO AND NORTHEAST KENTUCKY. HAVE ONE LOBE OF CONVECTION LIFTING NNE THROUGH THOSE COUNTIES 19Z TODAY TO 00Z SUNDAY. MORE SHOWERS WITH EMBEDDED THUNDERSTORMS COULD EASILY FORM OVERNIGHT EVEN 06Z TO 12Z. OUTSIDE OF THE CONVECTION...HAVE VSBY BECOMING 3 TO 5 MILES IN LIGHT FOG 06Z TO 12Z. HOPING LAYERED CLOUDS AND BOUNDARY LAYER WINDS KEEP THREAT FOG OUTSIDE OF THE CONVECTION FROM FORMING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM ALTERNATE SCENARIOS: HIGHLY VARIABLE CONDITIONS IN THE SHOWERS AND STORMS WITH CONDITIONS BRIEFLY GOING LOWER THAN FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H M M M M M M HTS CONSISTENCY H M M M M M M M M M M M BKW CONSISTENCY H H H H M H M M M M M H EKN CONSISTENCY H H H H H M M M M M M M PKB CONSISTENCY H H H H M M M M M M M M CKB CONSISTENCY M H H H H H M M M M M M AFTER 18Z SUNDAY... BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY AFTERNOON INTO TUESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...MZ AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
142 PM EDT SAT MAY 16 2015 .SYNOPSIS... A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL AFFECT THE REGION THIS WEEKEND. A COLD FRONT WILL APPROACH ON MONDAY...MOVING THROUGH BY EARLY TUESDAY. HIGH PRESSURE BUILDS IN DURING THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... PRECIPITATION HAS SLOWLY BEGUN TO INCREASE IN COVERAGE OVER THE PAST FEW HOURS...AND THIS TREND IS GENERALLY EXPECTED TO CONTINUE THROUGH EARLY TO MID AFTERNOON. AN ANALYSIS OF LOW-LEVEL WINDS INDICATES PERSISTENT SOUTHWESTERLY FLOW...BRINGING A CONTINUED TRANSPORT OF MOISTURE DIRECTLY INTO THE OHIO VALLEY. THERE IS CONVERGENCE AHEAD OF THIS MOISTURE ADVECTION...AND AS WEAK INSTABILITY BUILDS...THE COVERAGE AND INTENSITY SHOULD INCREASE AS WELL. POPS HAVE BEEN REFINED SLIGHTLY BUT REMAIN AT THE HIGH CHANCE TO LIKELY LEVELS ACROSS THE FORECAST AREA (PRIMARILY AROUND 18Z-21Z). IF THE HRRR VERIFIES...PRECIPITATION MAY END UP EVEN MORE WIDESPREAD...AND FUTURE UPDATES MAY NEED TO INCREASE THE PRECIPITATION CHANCES EVEN FURTHER. THE 12Z KILN SOUNDING IS VERY MOIST (PWAT OF 1.42 INCHES) WITH POOR LAPSE RATES THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE. THIS WILL LIMIT INSTABILITY TODAY...WITH A NARROW PROFILE OF CAPE THAT MAY GET TO AROUND 1000 J/KG AT MOST. WITH WEAK SHEAR...STORM ORGANIZATION SHOULD NOT BE MUCH TO SPEAK OF...AND THUS THE THREAT FOR STRONG STORMS APPEARS LOW. TEMPERATURES WERE ADJUSTED JUST SLIGHTLY DOWNWARD...WITH CONFIDENCE IN CLOUDS AND PRECIPITATION (AND A MOIST BOUNDARY LAYER) LIMITING HEATING POTENTIAL. PREVIOUS DISCUSSION > A FEW SHOWERS CONTINUE TO AFFECT WESTERN/CENTRAL OHIO AT 07Z. THIS ACTIVITY WILL CONTINUE TO MOVE NORTH-NORTHEAST OVER THE NEXT FEW HOURS...LIKELY DISSIPATING BY SUNRISE. RIDGE AXIS HAS SHIFTED A LITTLE EAST OF THE OHIO VALLEY EARLY THIS MORNING...RESULTING IN A BROAD SOUTHWEST FLOW ALOFT. WEAK VORT MAXES EMBEDDED WITHIN THIS FLOW WILL CONTINUE TO SUPPORT PERIODS OF CONVECTIVE ACTIVITY THROUGH THE DAY. IT LOOKS LIKE THE NEXT ROUND OF CONVECTION WILL LIKELY OCCUR IN NORTHERN KENTUCKY/SOUTHWEST OHIO BY 10-11Z...MOVING NORTHEAST DURING THE MORNING. THEN AN ADDITIONAL UPTICK IN CONVECTION WILL LIKELY OCCUR FOR THE MIDDAY/AFTERNOON GIVEN INCREASING PRECIPITABLE WATER VALUES /POSSIBLY AROUND 1.7 INCHES BY AFTERNOON/...AFTERNOON INSTABILITY AND THE LIKELIHOOD OF ANOTHER VORT MAX PROMOTING LIFT. WENT WITH HIGH CHANCE TO LOW END LIKELY POPS ACROSS THE CWA DURING THIS TIME. GIVEN RELATIVE WEAK INSTABILITY /MOST GUIDANCE SUGGESTING CAPE LESS THAN 1000 J/KG/ AND SHEAR...SEVERE WEATHER IS NOT EXPECTED. HOWEVER CAN/T RULE OUT A LOCALLY STRONG STORM WITH GUSTY WINDS AND ALSO GIVEN HIGHER MOISTURE CONTENT LOCALLY HEAVY DOWNPOURS MAY RESULT. USED A BLEND OF BIAS CORRECTED MET/MAV FOR HIGH TEMPERATURES TODAY...FAVORING UPPER 70S/AROUND 80 ACROSS MUCH OF THE CWA. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... WHILE COVERAGE OF CONVECTION FROM THE AFTERNOON/EARLY EVENING SHOULD WANE OVERNIGHT...WILL CONTINUE WITH LOW CHANCE POPS ACROSS THE CWA AS ATMOSPHERE WILL REMAIN WARM/MOIST AND ANY VORT MAX MAY KEEP SOME CONVECTION GOING INTO THE NIGHT. SIMILAR SITUATION IS EXPECTED ON SUNDAY...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGHOUT THE DAY BUT THE HIGHEST COVERAGE TO FAVOR THE AFTERNOON. A COLD FRONT IS THEN EXPECTED TO APPROACH ON MONDAY. WIND FIELDS MAY BE A LITTLE BETTER AND COULD PROMOTE SOME DEGREE OF ORGANIZATION TO THUNDERSTORMS. CONFIDENCE IS LOW HOWEVER AND WILL LEAVE MENTION OF STRONG/SEVERE STORMS OUT OF THE HWO ATTM. MONDAY WILL FEATURE ONE MORE WARM/MUGGY DAY BEFORE CHANGES OCCUR BEHIND THE FRONT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A COLD FRONT WILL THEN MOVE THROUGH THE AREA LATE MONDAY NIGHT AND TUESDAY MORNING WITH DRIER AND COOLER AIR MOVING IN BEHIND. MODELS HAVE SLOWED THE FRONT DOWN A BIT AND GIVEN CURRENT FORECASTED UPPER LEVEL FLOW THIS MAKES SENSE. THE UPPER LEVEL LOW JUST NORTH OF WISCONSIN MONDAY WASHES OUT WITH A SECONDARY SHORTWAVE MOVING SOUTH TUESDAY INTO WEDNESDAY. FORECASTED 850 TEMPERATURES FOR NEXT WEEK (5 - 10 DEGREES C) ALSO DON`T LOOK AS COOL AS THEY WERE OVER THE LAST COUPLE OF DAYS. HAVE TRENDED HIGH TEMPERATURES UP TOWARDS 70 A BIT TO ACCOUNT FOR THIS. BELOW NORMAL TEMPERATURES WILL THEN CONTINUE THROUGH THE END OF THE NEXT WORK WEEK. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... ALTHOUGH SCATTERED SHOWERS HAVE BEEN AROUND THE TAF SITES ALL MORNING...A MORE STEADY AREA OF RAIN (WITH EMBEDDED CONVECTION) IS NOW MOVING INTO THE CINCINNATI AIRPORTS...AND WILL SPREAD NORTH TO DAYTON AND COLUMBUS IN THE NEXT COUPLE HOURS. PREVAILING MVFR CONDITIONS ARE EXPECTED...THOUGH A HEAVY DOWNPOUR COULD BRING BRIEF IFR CONDITIONS. THUNDER REMAINS A POSSIBILITY...BUT FOR THE MOST PART THERE HAS NOT BEEN AN ABUNDANCE OF LIGHTNING OBSERVED IN THE CURRENT PRECIPITATION...SO THIS HAS NOT BEEN INCLUDED SPECIFICALLY IN THE TAFS. RAIN IS EXPECTED TO BECOME MORE SCATTERED THIS EVENING AND INTO THE OVERNIGHT. HOWEVER...MVFR CEILINGS ARE EXPECTED TO REMAIN IN PLACE. THERE IS THE POTENTIAL FOR ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT LATE IN THE TAF PERIOD...BOTH EARLY SUNDAY MORNING AS WELL AS SUNDAY AFTERNOON. THE EXACT TIMING AND INTENSITY OF THIS POTENTIAL DEVELOPMENT IS UNCERTAIN...SO A VCSH WILL BE USED THROUGHOUT THE REST OF THE TAF PERIOD. WINDS THROUGH THE TAF PERIOD WILL BE OUT OF THE SSW...GENERALLY AT AROUND 10 KNOTS. OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE AT TIMES ON SUNDAY AND MONDAY. MVFR CEILINGS MAY ALSO OCCUR AT TIMES ON SUNDAY AND MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BPP NEAR TERM...HATZOS/BPP SHORT TERM...BPP LONG TERM...HAINES AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1000 AM EDT SAT MAY 16 2015 .SYNOPSIS... A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL AFFECT THE REGION THIS WEEKEND. A COLD FRONT WILL APPROACH ON MONDAY...MOVING THROUGH BY EARLY TUESDAY. HIGH PRESSURE BUILDS IN DURING THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... PRECIPITATION HAS SLOWLY BEGUN TO INCREASE IN COVERAGE OVER THE PAST FEW HOURS...AND THIS TREND IS GENERALLY EXPECTED TO CONTINUE THROUGH EARLY TO MID AFTERNOON. AN ANALYSIS OF LOW-LEVEL WINDS INDICATES PERSISTENT SOUTHWESTERLY FLOW...BRINGING A CONTINUED TRANSPORT OF MOISTURE DIRECTLY INTO THE OHIO VALLEY. THERE IS CONVERGENCE AHEAD OF THIS MOISTURE ADVECTION...AND AS WEAK INSTABILITY BUILDS...THE COVERAGE AND INTENSITY SHOULD INCREASE AS WELL. POPS HAVE BEEN REFINED SLIGHTLY BUT REMAIN AT THE HIGH CHANCE TO LIKELY LEVELS ACROSS THE FORECAST AREA (PRIMARILY AROUND 18Z-21Z). IF THE HRRR VERIFIES...PRECIPITATION MAY END UP EVEN MORE WIDESPREAD...AND FUTURE UPDATES MAY NEED TO INCREASE THE PRECIPITATION CHANCES EVEN FURTHER. THE 12Z KILN SOUNDING IS VERY MOIST (PWAT OF 1.42 INCHES) WITH POOR LAPSE RATES THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE. THIS WILL LIMIT INSTABILITY TODAY...WITH A NARROW PROFILE OF CAPE THAT MAY GET TO AROUND 1000 J/KG AT MOST. WITH WEAK SHEAR...STORM ORGANIZATION SHOULD NOT BE MUCH TO SPEAK OF...AND THUS THE THREAT FOR STRONG STORMS APPEARS LOW. TEMPERATURES WERE ADJUSTED JUST SLIGHTLY DOWNWARD...WITH CONFIDENCE IN CLOUDS AND PRECIPITATION (AND A MOIST BOUNDARY LAYER) LIMITING HEATING POTENTIAL. PREVIOUS DISCUSSION > A FEW SHOWERS CONTINUE TO AFFECT WESTERN/CENTRAL OHIO AT 07Z. THIS ACTIVITY WILL CONTINUE TO MOVE NORTH-NORTHEAST OVER THE NEXT FEW HOURS...LIKELY DISSIPATING BY SUNRISE. RIDGE AXIS HAS SHIFTED A LITTLE EAST OF THE OHIO VALLEY EARLY THIS MORNING...RESULTING IN A BROAD SOUTHWEST FLOW ALOFT. WEAK VORT MAXES EMBEDDED WITHIN THIS FLOW WILL CONTINUE TO SUPPORT PERIODS OF CONVECTIVE ACTIVITY THROUGH THE DAY. IT LOOKS LIKE THE NEXT ROUND OF CONVECTION WILL LIKELY OCCUR IN NORTHERN KENTUCKY/SOUTHWEST OHIO BY 10-11Z...MOVING NORTHEAST DURING THE MORNING. THEN AN ADDITIONAL UPTICK IN CONVECTION WILL LIKELY OCCUR FOR THE MIDDAY/AFTERNOON GIVEN INCREASING PRECIPITABLE WATER VALUES /POSSIBLY AROUND 1.7 INCHES BY AFTERNOON/...AFTERNOON INSTABILITY AND THE LIKELIHOOD OF ANOTHER VORT MAX PROMOTING LIFT. WENT WITH HIGH CHANCE TO LOW END LIKELY POPS ACROSS THE CWA DURING THIS TIME. GIVEN RELATIVE WEAK INSTABILITY /MOST GUIDANCE SUGGESTING CAPE LESS THAN 1000 J/KG/ AND SHEAR...SEVERE WEATHER IS NOT EXPECTED. HOWEVER CAN/T RULE OUT A LOCALLY STRONG STORM WITH GUSTY WINDS AND ALSO GIVEN HIGHER MOISTURE CONTENT LOCALLY HEAVY DOWNPOURS MAY RESULT. USED A BLEND OF BIAS CORRECTED MET/MAV FOR HIGH TEMPERATURES TODAY...FAVORING UPPER 70S/AROUND 80 ACROSS MUCH OF THE CWA. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... WHILE COVERAGE OF CONVECTION FROM THE AFTERNOON/EARLY EVENING SHOULD WANE OVERNIGHT...WILL CONTINUE WITH LOW CHANCE POPS ACROSS THE CWA AS ATMOSPHERE WILL REMAIN WARM/MOIST AND ANY VORT MAX MAY KEEP SOME CONVECTION GOING INTO THE NIGHT. SIMILAR SITUATION IS EXPECTED ON SUNDAY...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGHOUT THE DAY BUT THE HIGHEST COVERAGE TO FAVOR THE AFTERNOON. A COLD FRONT IS THEN EXPECTED TO APPROACH ON MONDAY. WIND FIELDS MAY BE A LITTLE BETTER AND COULD PROMOTE SOME DEGREE OF ORGANIZATION TO THUNDERSTORMS. CONFIDENCE IS LOW HOWEVER AND WILL LEAVE MENTION OF STRONG/SEVERE STORMS OUT OF THE HWO ATTM. MONDAY WILL FEATURE ONE MORE WARM/MUGGY DAY BEFORE CHANGES OCCUR BEHIND THE FRONT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A COLD FRONT WILL THEN MOVE THROUGH THE AREA LATE MONDAY NIGHT AND TUESDAY MORNING WITH DRIER AND COOLER AIR MOVING IN BEHIND. MODELS HAVE SLOWED THE FRONT DOWN A BIT AND GIVEN CURRENT FORECASTED UPPER LEVEL FLOW THIS MAKES SENSE. THE UPPER LEVEL LOW JUST NORTH OF WISCONSIN MONDAY WASHES OUT WITH A SECONDARY SHORTWAVE MOVING SOUTH TUESDAY INTO WEDNESDAY. FORECASTED 850 TEMPERATURES FOR NEXT WEEK (5 - 10 DEGREES C) ALSO DON`T LOOK AS COOL AS THEY WERE OVER THE LAST COUPLE OF DAYS. HAVE TRENDED HIGH TEMPERATURES UP TOWARDS 70 A BIT TO ACCOUNT FOR THIS. BELOW NORMAL TEMPERATURES WILL THEN CONTINUE THROUGH THE END OF THE NEXT WORK WEEK. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... UNSETTLED WEATHER OVER THE OHIO VALLEY WILL NECESSITATE SOME TYPE OF SHOWER AND THUNDERSTORM MENTION AT ALL TAF SITES FOR THE FORESEEABLE FUTURE. SOUTHERLY FLOW WILL CONTINUE TO PUMP INCREASED MOISTURE TO THE REGION AND MID LEVEL SHORTWAVES WILL TRAVERSE A H5 RIDGE THAT IS IN PLACE OVER THE EASTERN U.S. THIS ESTABLISHED RIDGE WILL KEEP MOST STORMS IN CHECK AND THE CONSENSUS IN THE NEXT DAY OR TWO IS FOR GARDEN VARIETY THUNDERSTORMS OF A SCATTERED NATURE BECOMING MORE NUMEROUS DURING THE DAY. SHOWERS AND OCCASIONAL THUNDERSTORMS WILL DROP VSBYS TO MVFR VALUES BUT MOST CIGS SHOULD REMAIN VFR FOR THE NEXT 24-30 HOURS. SATURATED CONDITIONS THROUGH THE LOWER ATMOSPHERE WILL BE FOUND AT VARIOUS LEVELS THAT WILL BE AS DIFFICULT TO PINPOINT AS THE LOCATIONS OF THE STORMS. CONTINUE TO LEAVE OUT MVFR CIGS FROM CU/SC WHILE DROPPING THEM SLIGHTLY IN PRECIP WHICH IS MORE HEAVILY FOCUSED IN TEMPO GROUPS. WINDS WILL BE SSW AT 10KT OR LESS. OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY THROUGH MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...BPP NEAR TERM...HATZOS/BPP SHORT TERM...BPP LONG TERM...HAINES AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
941 AM EDT SAT MAY 16 2015 .SYNOPSIS... WEAK MID/UPPER LEVEL DISTURBANCES...INCREASED MOISTURE AND INSTABILITY RESULTS IN ROUNDS OF SHOWERS/THUNDERSTORMS INTO EARLY NEXT WEEK. COLD FRONT PUSHES EAST TUESDAY. DRIER WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... FROM 00Z TO 12Z SOUNDINGS...SHOW PRECIPITABLE WATER AT BNA INCREASED FROM 1.3 TO 1.7 INCHES...AT ILN FROM 1.1 TO 1.4 INCHES. PIT DID NOT INCREASE MUCH IN PAST 12 HRS. VERY WEAK 500 MB VORT MAX ON RAP LIFTS FROM HTS VCNTY AT 13Z THROUGH NORTH CENTRAL WV 17-19Z...BUT OVERALL 500 HEIGHTS ARE NOT FALLING. AS A RESULT...INCREASED POPS A BIT QUICKER IN WESTERN WEST VIRGINIA THIS MORNING INTO EARLY AFTERNOON. ANOTHER 500 MB DISTURBANCE MAY LIFT OUT OF TENNESSEE RIVER VALLEY TODAY...REACHING US TONIGHT. WE MAINTAIN AT LEAST CHANCE POPS THROUGH THE NIGHT. WITH PLENTY OF LAYERED CLOUDS OVERNIGHT...DID NOT HIT FOG HARD OVERNIGHT FOR THE PUBLIC...BUT COULD EASILY BE 3 TO 5 MILES. DID LOWER MAX TEMP A FEW DEGREES IN SOUTHEAST OHIO AND NRN WV TODAY...FIGURING ON THE AFFECTS OF THIS FIRST DISTURBANCE. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... MODELS SHOW H500 RIDGE AXIS MOVING OVER WV SUNDAY. THE CMC/NAM/GFS MODELS SHOW FEW VORTICITY MAX ALONG THIS RIDGE FLOW FROM 12Z SUNDAY THROUGH 00Z MONDAY. MODELS ALSO SHOW AN INCREASE IN PRECIPITABLE WATER REACHING 1.9 INCHES BY 18Z SUNDAY. H850 FLOW BECOMES STEADY FROM THE SOUTHWEST PUMPING JUICIER AND WARMER AIR MASS TO THE AREA. THUS...UNSETTLED ATMOSPHERE...WITH SFC CAPE FROM 1800-2000 J/KG SUGGEST GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS MAINLY DURING THE AFTERNOON HOURS. BY MONDAY...A COLD FRONT CROSSES THE OH VALLEY...KEEPING OUR AREA UNDER A WARM SECTOR. WITH BETTER SUPPORT FROM THIS COLD FRONT...SUSPECT CONVECTION AHEAD OF THE FRONT WILL LIGHT UP TO ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER AROUND 1.7 AHEAD OF THE FRONT SUGGEST SOME STORMS COULD PRODUCE HEAVY DOWNPOURS MONDAY. KEPT LIKELY POPS WITH THIS ENVIRONMENT. THE COLD FRONT SHOULD REACH SOUTHEAST OH BY 12Z TUESDAY...CROSSING EAST ENDING PCPN BY 00Z WEDNESDAY. EXPECT ABOVE NORMAL TEMPERATURES SUNDAY AND MONDAY BECOMING NEAR NORMAL TUESDAY. USED A BLEND OF PREVIOUS NUMBERS AND THE BIAS CORRECTED CONSENSUS ALL GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A COLD FRONT WILL PUSH THROUGH MONDAY NIGHT. ECMWF HAS PERSISTENTLY BEEN PUSHING IT THROUGH CLEANLY...WHILE THE GFS HAS AT TIMES SHOWED SIGNS OF IT GETTING HUNG UP...BUT RECENTLY HAS BEEN SHOWING THE CLEAN SWEET AS WELL. SO MINIMAL CHANGES TO PREVIOUS FORECAST...WITH DRIER AND COOLER AIR FILTERING IN MID WEEK. THINGS MAY GET A LITTLE MESSIER AT THE END OF THE WEEK AND INTO THE WEEKEND AS MOISTURE BEGINS TO RETURN. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... 06Z SATURDAY THRU 06Z SUNDAY... ISOLATED STORMS HAVE PUSHED EAST OF THE AREA AT THIS TIME. VFR CONDITIONS PREVAILED IN MOST LOCATIONS...WITH SOME VALLEY LOCATIONS SEEING MVFR AND EVEN IFR VSBYS. ADDITIONAL SHOWERS AND STORMS...WHICH WERE APPROACHING FROM THE WEST...SHOULD SPREAD EAST ACROSS THE REGION...AND INCREASE IN AREAL COVERAGE. CURRENT THINKING IS THE GREATEST CONCENTRATION OF STORMS SHOULD OCCUR BETWEEN 17Z AND 23Z. EXPECT BRIEF MVFR AND IFR CONDITIONS IN VICINITY OF STORMS. GUSTY WINDS ARE ALSO POSSIBLE WITH THE STRONGER STORMS. THE STORMS SHOULD BEGIN TO DECREASE IN INTENSITY AND AREAL COVERAGE AFTER 03Z. WHILE CONDITIONS SHOULD BE VFR IN MOST LOCATIONS...MVFR AND IFR CONDITIONS WILL BE POSSIBLE ALONG RIVER VALLEYS AND IN AREAS THAT RECEIVED RAINFALL TODAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY... FORECAST CONFIDENCE: MEDIUM ALTERNATE SCENARIOS: STORMS WITH ISOLATED CONDITIONS MAY NOT BE AS NUMEROUS AS EXPECTED. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY M H M H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H M H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z SUNDAY... BRIEF IFR IN THUNDERSTORMS POSSIBLE THROUGH TUESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/KTB/ARJ NEAR TERM...KTB SHORT TERM...ARJ LONG TERM...MZ AVIATION...JSH
AREA FORECAST DISCUSSION
NWS TULSA OK
935 PM CDT SUN MAY 17 2015 .DISCUSSION... A MUCH QUIETER EVENING AS THE AREA HAS REMAINED PRECIP FREE FOR THE DURATION. BOUNDARY SEPARATING DEW POINTS IN UPPER 60S TO NEAR 70S FROM DRIER AIR EXTENDS FROM SOUTH CENTRAL OK INTO WESTERN OSAGE COUNTY AND NEAR THIS INTERFACE WITH LIGHT WINDS SOME FOG DEVELOPMENT REMAINS POSSIBLE. WARM MOIST SECTOR OVER WESTERN OK AND WESTERN AR REMAINS CAPPED AND SHORT RANGE GUIDANCE INCLUDING THE 00Z NAM TRENDING TOWARD A DRIER SOLUTION FOR TONIGHT. WILL KEEP SLIGHT CHANCE ACROSS FAR EASTERN/SOUTHERN AREAS AS A SUBTLE WAVER MOVES ACROSS TONIGHT AND MAY HAVE JUST ENOUGH LIFT TO SPARK A FEW SHOWERS LATE TONIGHT OR EARLY MON MORNING. UPDATED PRODUCTS WILL BE OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 634 PM CDT SUN MAY 17 2015/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. SCATTERED TO BROKEN MID/HIGH CLOUDS WILL CONTINUE OVERNIGHT AS WEAK UPPER DISTURBANCE TRAVERSES THE AREA. COULD SEE SOME LIGHT FOG TOWARDS MORNING AS WINDS BECOME LIGHT AHEAD OF APPROACHING FRONTAL BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. PREV DISCUSSION... /ISSUED 359 PM CDT SUN MAY 17 2015/ DISCUSSION... NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER SHORT TERM HRRR LOOKS GOOD TONIGHT. NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST. CHANCE POPS THURSDAY INTO FRIDAY. UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY. ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND. GW && .PRELIMINARY POINT TEMPS/POPS... TUL 64 83 60 75 / 10 10 10 10 FSM 68 84 66 81 / 20 30 20 20 MLC 67 84 63 80 / 10 20 20 30 BVO 58 81 54 72 / 10 10 10 10 FYV 62 81 58 76 / 20 30 20 10 BYV 64 81 57 75 / 20 30 20 10 MKO 64 83 61 77 / 10 10 10 30 MIO 63 80 56 73 / 10 10 10 10 F10 64 83 61 77 / 10 10 10 30 HHW 68 83 67 81 / 30 30 20 40 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...14 LONG TERM....99
AREA FORECAST DISCUSSION
NWS TULSA OK
634 PM CDT SUN MAY 17 2015 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. SCATTERED TO BROKEN MID/HIGH CLOUDS WILL CONTINUE OVERNIGHT AS WEAK UPPER DISTURBANCE TRAVERSES THE AREA. COULD SEE SOME LIGHT FOG TOWARDS MORNING AS WINDS BECOME LIGHT AHEAD OF APPROACHING FRONTAL BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. && .PREV DISCUSSION... /ISSUED 359 PM CDT SUN MAY 17 2015/ DISCUSSION... NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER SHORT TERM HRRR LOOKS GOOD TONIGHT. NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST. CHANCE POPS THURSDAY INTO FRIDAY. UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY. ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND. GW && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...12
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1202 PM EDT SAT MAY 16 2015 .SYNOPSIS... A STALLED FRONTAL ZONE WILL BE THE FOCUS FOR PERIODS OF UNSETTLED WEATHER THIS WEEKEND...AS SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH DAY. THE WEEKEND WILL NOT BE A WASHOUT...AS THERE WILL BE DRY TIMES WITH PERIODS OF SUNSHINE AS WELL. A RELATIVELY STRONG COLD FRONT WILL PUSH ACROSS THE AREA MONDAY NIGHT AND TUESDAY...USHERING IN ANOTHER COOL...DRY AIRMASS FOR LATE TUESDAY THROUGH THURSDAY. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... 1150 AM UPDATE... CONVECTIONWANED FOR A BIT...BUT STARTING UP AGAIN. HRRR HAS A GREAT HANDLE ON CURRENT CROP OF STORMS...INCL THE STUFF NEAR KHLG/KPIT AND KBFD. HEATING WILL POP CONVECTION IN MANY MORE LOCATIONS AS THE SHORT WAVE DRIVING THE CURRENT ACTIVITY RUNS INTO THE CURRENTLY SUNNY AREA. WILL KNOCK TEMPS DOWN A BIT IN THE NW AND UP SLIGHTLY FOR THE NEXT FEW HRS IN THE SE. THEN WIDESPREAD CONVECTION SHOULD COOL IT OFF. SEVERE THREAT STILL LURKING AROUND THE CORNER...WITH BEST GUIDANCE ALSO INDICATING SOME STRONGER WINDS ALOFT. WOULD NOT BE SURPRISED TO SEE A BOX SOMETIME THIS AFTN...ESP IF THE CLUSTER OVER KPIT CONTINUES TO INCREASE IN COVG/INTENSITY...WHICH SEEMS MORE THAN LIKELY. PREV... SCATTERED SHOWERS CONTINUE TO TRACK ACROSS THE NORTHERN HALF OF CENTRAL PA...NOW ACCOMPANIED BY ISOLATED THUNDER AS STATIC STABILITY HAS DECREASED OVERNIGHT WITH THE PASSING OF A SHORTWAVE TROF FROM THE EASTERN GLAKS CROSSING THE FINGERLAKES REGION. MARGINALLY UNSTABLE AIR MASS WITH MODERATE MOISTURE (PW ~1.5") AND BOUNDARY LAYER CONVERGENCE INVOF STALLED WARM FRONT WILL FOCUS SHOWER AND THUNDERSTORM CHANCES THROUGHOUT THE DAY. SHOWERS WILL BE MOST PROBABLE AND NUMEROUS ACROSS THE NORTHERN HALF OF CENTRAL PA...BUT EVEN THE SOUTH CAN SEE AN ISOLATED SHOWER OR THUNDERSTORM AT JUST ABOUT ANY TIME...BUT MOST LIKELY DURING MAX DIURNAL HEATING THIS AFTERNOON. N CENTRAL PA IS IN MARGINAL SPC OUTLOOK FOR THIS AFTERNOON...SO WILL BE WATCHFUL FOR PULSE STORMS WHICH COULD PRODUCE HEAVY DOWNPOURS...GUSTY WINDS AND SMALL HAIL. HIGHS WILL RANGE FROM THE MID 70S NORTH WHERE CLOUDS WILL BE THICKEST AND SHOWERS AT THEIR MOST FREQUENT...TO THE LOWER TO MIDDLE 80S SOUTHEAST. && .SHORT TERM /10 PM THIS EVENING THROUGH 6 PM SUNDAY/... AFOREMENTIONED QUASISTATIONARY BOUNDARY WILL BE DRAPED ACROSS PA TONIGHT INTO EARLY SUNDAY BEFORE SETTLING SOUTHWARD SUNDAY AFTERNOON AS DRIER AND COOLER AIR WORKS SOUTHWARD FROM HIGH PRESSURE OVER NORTHERN NEW ENGLAND AND NEWFOUNDLAND. WHILE THE TREND WILL BE FOR DECREASING SHOWER ACTIVITY...A SHOWER OR TSTM CAN/T BE RULED OUT AT PRACTICALLY ANY TIME DURING THIS PERIOD. KEPT POPS IN THE LOWER TO MID CHC RANGE FROM TONIGHT THROUGH SUNDAY MORNING...WITH DECREASING POPS SUNDAY AFTERNOON. LOWS TONIGHT WILL RANGE FROM THE UPPER 50S NORTH TO THE MID 60S SOUTHEAST. HIGHS WILL ONCE AGAIN RANGE FROM THE MID 70S NORTH TO AROUND 80 OVER THE LOWER SUSQ. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... LEAD SHORTWAVE ENERGY CLIMBING THE WESTERN-SIDE OF ANOMALOUS 500MB RIDGE OVER THE EASTERN US...ALONG WITH ABOVE NORMAL PWATS AND DIURNAL INSTABILITY WILL HELP PROMOTE SCATTERED CONVECTION ON SUNDAY...ESPECIALLY ALONG/SOUTH OF THE QUASI-STNRY/WARM FRONTAL BOUNDARY PIVOTING OVER THE AREA. USED A BLEND FOR POPS/QPF WHICH FAVORED THE LAUREL HIGHLANDS AND SOUTH-CENTRAL MTNS ON DAY 3. GIVEN LACK OF FORCING AND LOSS OF DAYTIME HEATING...CUT BACK POPS TO THE MID-CHC RANGE SUNDAY NIGHT /40 PERCENT WEST TO 30 PERCENT EAST/. THE VIGOROUS/DEEP CLOSED LOW EJECTING OUT OF THE SOUTHWESTERN U.S. SHOULD REACH THE NORTHERN PLAINS BY 00Z MON...WHERE THE MODELS SHOW IT SLOWING DOWN AND EVENTUALLY BECOMING ABSORBED INTO AN UPPER TROUGH CROSSING HUDSON BAY. THIS HAS APPEARED TO SLOW THE EASTWARD PROGRESSION OF ITS TRAILING COLD FRONT BY 12HRS OR SO...NOW PROGGED TO CROSS THE AREA DURING THE DAYTIME ON TUESDAY (PREVIOUSLY MONDAY NIGHT/AM TUESDAY). THIS SLOWER TREND WAS EVIDENT IN THE GUIDANCE AND HAVE ADJUSTED TEMPS AND POPS ACCORDINGLY. THE PARENT SHORTWAVE WILL LOSE MUCH OF ITS AMPLITUDE AS IT TRACKS THROUGH THE UPPER GREAT LAKES AND FOR NOW DOES NOT APPEAR TO POSE A SIGNIFICANT SVR WX RISK FOR EARLY NEXT WEEK. IN THE WAKE OF THE COLD FRONTAL PASSAGE...A RESPECTABLE ANTICYCLONE WILL EXTEND SEWD FROM THE UPPER MIDWEST WITH COOLER AND NOTICEABLY DRIER AIR FILTERING INTO THE REGION FOR THE MID TO LATE WEEK PERIOD. THIS PATTERN SHOULD SUPPRESS THE PCPN RISK TO THE SOUTH OF CENTRAL PA WITH GENERALLY FAIR WEATHER AND SEASONABLY COOL TO MODERATING TEMPERATURES PREVAILING AT DAYS 6-8. ALSO OF NOTE IS THE RISK FOR PATCHY FROST ON MAY 21ST/THURSDAY MORNING MAINLY OVER THE NORTH-CENTRAL ZONES WHERE ECENS/GFS ENSEMBLE MOS GUIDANCE IS SHOWING MID 30S AT BFD...JUST IN TIME FOR THE START OF THE GROWING SEASON. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... NOON... CONVECTION MOVING BACK IN FROM THE WEST. WILL ATTEMPT TO TIME IT INTO JST/AOO/IPT. WINDS MAY BE ERRATIC/GUSTY IN THUNDERSTORMS...BUT TOO TIGHT OF A WINDOW TO TRY TO MAKE MORE THAN A TEMPO MENTION OF THAT. PREV... THE LAST REMAINING CLUSTER OF SHOWERS AND THUNDERSTORMS HAVE MOVED PAST IPT AND ARE CONTINUING TO PROGRESS EASTWARD. EXPECT A LULL IN THE PRECIPITATION THROUGH THE MORNING. HOWEVER AS THE WARM FRONT LAGS...AND THE TEMPERATURES RISE...PRECIPITATION WILL BEGIN TO BUBBLE AND MOVE THROUGH CENTRAL PA...AFFECTING MOST TAF SITES AT TIMES THIS AFTERNOON AND EARLY EVENING. HOWEVER VFR CIGS AND VSBYS WILL BE DOMINATE WITH MVFR TO IFR IN HEAVIER SHOWERS AND THUNDERSTORMS. THE STRONGEST STORMS SHOULD BE ALONG THE SOUTHERN CORRIDOR OF PENNSYLVANIA...AFFECTING JST...AOO...MDT AND LNS. SHOWERS COULD CONTINUE OVERNIGHT...WITH MVFR CIGS POSSIBLE AFTER 03Z. BFD COULD SEE IFR BY THIS TIME DUE TO CALMING WINDS AND COPIOUS AMOUNTS OF LOW LEVEL MOISTURE PRESENT. THIS ALSO REMAINS POSSIBLE AT UNV. WINDS SHOULD PERSIST AT JST WHICH SHOULD ONLY ALLOW MVFR...THOUGH IFR REMAINS POSSIBLE...THOUGH LOWER PROBABILITY. OUTLOOK... SUN-TUE MORNING...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WITH LOCAL REDUCTIONS TO MVFR AND BRIEF IFR POSSIBLE. WED-THU...MAINLY VFR WITHIN A COOLER/DRIER AIRMASS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR NEAR TERM...DANGELO/DEVOIR SHORT TERM...DEVOIR/LAMBERT LONG TERM...STEINBUGL AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
653 AM EDT SAT MAY 16 2015 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE WEEKEND. INCREASING MOISTURE OVER THE WESTERN EDGE OF THE HIGH WILL BRING PRECIPITATION CHANCES MAINLY TO THE MOUNTAINS TODAY AND SUNDAY. A COLD FRONT APPROACHES MONDAY...POSING BETTER CHANCES FOR PRECIPITATION FOR THE WHOLE AREA THROUGH TUESDAY. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL RETURN WEDNESDAY IN THE WAKE OF THE FRONT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 655 AM EDT...THE EARLY MORNING HOURS HAVE TRENDED LESS CLOUDY OVER THE HEART OF THE FORECAST AREA...WHICH HAS PERMITTED SOME PATCHY DENSE FOG TO FORM OVER THE NC FOOTHILLS...MAINLY NEAR MORGANTON. A LOWER CLOUD DECK DID MANAGE TO DEVELOP ALONG INTERSTATE 77...BUT THIS SHOULD BE MUCH SHORTER LIVED THAN THE LOW CLOUDS OBSERVED YESTERDAY MORNING GIVEN THE SMALLER SPATIAL EXTENT OF THE CLOUDS AND EXPECTED MORNING HEATING. OTHERWISE...A BROAD UPPER LEVEL RIDGE AXIS WILL REMAIN IN PLACE OVER THE EASTERN THIRD OF THE NATION TODAY THROUGH TONIGHT. THE BEST LOW TO MID LEVEL MOISTURE RETURN AROUND THE RIDGE WILL CONTINUE TO AFFECT THE SPINE OF THE SRN APPALACHIANS THROUGH THE PERIOD. WITH LOW LEVEL WINDS VEERED MORE S TO SW TODAY...TRIGGERING OF SHRA AND LATER DAY TSRA MAY BE EVEN MORE CONFINED TO THE MTNS...ESPECIALLY NEAR THE TN BORDER...THAN OBSERVED ON FRI. THERE WILL BE MUCH LESS IN THE WAY OF EARLY DAY LOW CLOUDS...BUT STILL EXPECT OCNL MID AND HIGH LEVEL CLOUDS TOPPING THE ERN RIDGE...ALONG WITH A DEVELOPING CUMULUS FIELD FROM THE RECOVERING SFC DEWPOINTS AND HEATING. ALL TOLD...ENOUGH INSOLATION IS EXPECTED TO PERMIT TEMPS TO WARM INTO THE UPPER 70S TO NEAR 80 IN THE LOWER MTN VALLEYS AND 80 TO 85 EAST OF THE MTNS. SBCAPE VALUES ALONG THE SPINE OF THE MTNS MAY REACH 1000 TO 1500 J/KG...WITH LESSER INSTABILITY EAST DUE TO MORE NEGATIVE BUOYANCY AREAS IN THE MODEL PROFILES AND BETTER MID LEVEL CAPPING. STEERING FLOW WILL ONCE AGAIN BE LIGHT...WITH LIGHTNING AND LOCALLY HEAVY RAINFALL IN THE MTNS THE PRIMARY THREATS WITH ANY THUNDERSTORMS. LINGERING EVENING ISOLD TO SCT SHRA/TSRA IN THE MTNS WILL DIMINISH QUICKLY TONIGHT AND LIKELY DISSIPATE EVERYWHERE BUT THE FAR SW MTNS OVERNIGHT. MIN TEMPS SHOULD GAIN ANOTHER DEGREE OR SO AS THE AIRMASS CONTINUES TO MODIFY UNDER SRLY FLOW. IF THE HIGH CLOUDS THIN SUFFICIENTLY...MTN VALLEY FOG WILL BECOME MORE LIKELY LATE TONIGHT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 230 AM SAT...SHARP UPPER RIDGE WILL BE SITUATED OVER THE ERN SEABOARD SUNDAY AS A WELL DEVELOPED LOW PRESSURE SYSTEM MOVES INTO THE UPPER MISSISSIPPI VALLEY. SW FLOW OFF THE GULF WILL CONTINUE THRU SUN AFTN...AND CONVECTION IS EXPECTED TO INITIATE OVER THE MTNS IN TYPICAL FASHION. HOWEVER FAVORABLE PROFILES ARE SEEN ON NAM PROGS INTO THE FOOTHILLS AS WELL. THE RIDGE PUSHES EWD IN ADVANCE OF THE LOW SUNDAY NIGHT...ALLOWING SLIGHTLY LOWER HEIGHTS ALOFT MONDAY. THIS WILL MAKE FOR MORE UNSTABLE CONDITIONS WHICH SPREAD ACRS THE CWFA. COLD FRONT ASSOC WITH THE LOW CONTINUES TO APPROACH MON NIGHT BUT APPRECIABLE COLD ADVECTION DOES NOT ARRIVE UNTIL NEAR DAYBREAK TUE. WHILE MOIST PROFILES MAY STILL BE PRESENT MON NIGHT...CONVECTION GENERALLY LOOKS TO WANE WITH THE LOSS OF HEATING. THREATS WILL PRIMARILY BE HEAVY RAIN EACH DAY...WITH PWAT VALUES PROGGED TO BE ABOVE THE 75TH PERCENTILE AND WEAK FLOW IMPLYING SLOW MOVING STORMS. THE UPSIDE OF THE MOIST PROFILES IS THAT DOWNBURST THREAT WILL BE FAIRLY LOW. TEMPS TREND UPWARD FROM SUN TO MON BUT WITH AFTN MAXES SEVERAL DEGREES ABOVE CLIMO BOTH DAYS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 250 AM SAT...AS SFC LOW MOVES ACRS QUEBEC TUESDAY...COLD FRONT WILL MOVE OFF THE MID-ATLANTIC COAST. ASSOCIATED CONVERGENCE ZONE WILL LIKELY ENHANCE CONVECTIVE COVERAGE OVER OUR PIEDMONT REGION WHERE SIMILAR INSTABILITY WILL BE IN PLAY COMPARED TO THAT OF MONDAY. HOWEVER THE MTNS WILL SEE LESS UNSTABLE CONDITIONS ON ACCOUNT OF THE INCOMING CONTINENTAL AIRMASS. BY WED THIS WILL HAVE SPREAD ACROSS THE WHOLE CWFA. DRY AND SETTLED WEATHER MAY BE SHORT LIVED AS THE NRN STREAM CONTINUES TO FEATURE A TROUGH TO OUR NORTH LATE IN THE WEEK...AROUND WHICH DISTURBANCES OR MINOR SHORTWAVES WILL PASS ATOP A WEAK STATIONARY BOUNDARY ON THE SRN FRINGE OF THE HIGH. THIS WILL BRING SMALL PRECIP CHANCES BACK THU...GFS AND EC SHOWING SOME DIFFERENCES /AND RUN-TO-RUN VARIATION/ IN EXACTLY WHERE THAT BOUNDARY SETS UP. INSTABILITY WILL REMAIN ON ITS WARM SIDE SUPPORTING POPS EVEN IF ANY UPGLIDE OVER IT IS TOO WEAK. DIURNAL INSTABILITY LOOKS TO RETURN BY FRIDAY ANYWAY AS POPS AGAIN EXHIBIT A CLIMATOLOGICAL FOCUS ON THE MTNS. CONFIDENCE IS LOW ON THE TEMP FCST...WITH A COOLING TREND AND RETURN TO NEAR-NORMAL READINGS LIKELY IF THE BOUNDARY SETTLES PAST THE AREA...BUT ABOVE NORMAL MAX TEMPS CONTINUING IF IT STALLS TO THE NORTH. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...AN MVFR DECK HAS FORMED OVERHEAD...BUT IT SHOULD BE FAIRLY SHORT LIVED SINCE IT HAS LIMITED SPATIAL EXTENT AND RAP PROFILES DISSIPATE THE LOW LEVEL MOISTURE QUICKLY THROUGH 14Z. OTHERWISE...EXPECT MAINLY SCT TO BKN HIGHER LEVEL VFR CLOUDS SPILLING OVER THE RIDGE THROUGH THE PERIOD...WITH CONVECTIVE CUMULUS FILLING IN AT 5 TO 6 KFT DURING THE PEAK HEATING HOURS. SURFACE WINDS WILL REMAIN SOLIDLY S TO SW AT SPEEDS LESS THAN 10 KT. MODEL PROFILES ALL STILL EXHIBIT A WEAK SUBSIDENCE CAP WHICH WILL LIMIT ANY PIEDMONT CONVECTION. ELSEWHERE...KAVL WILL SEE A CHANCE OF A SHOWER OR LATE DAY THUNDERSTORM...BUT WITH SLIGHTLY MORE CAPPING IN PROFILES DIMINISHING THE CHANCES FARTHER EAST OVER THE FOOTHILLS. EXPECT OCNL VFR CIGS THROUGHOUT...WITH MID AND HIGH LEVEL CIGS TOPPING THE UPPER RIDGE AXIS EARLY AND LATE...AND PERHAPS CONVECTIVE CUMULUS CIGS AT 5 TO 6 KFT WITH PEAK HEATING. SRLY WINDS WILL REMAIN 10 KT OR LESS THROUGH THE PERIOD. BRIEF FOG IS POSSIBLE MAINLY NEAR KHKY AROUND DAYBREAK THIS MORNING...AND AT KAVL LATE TONIGHT. OUTLOOK...A PLUME OF MOISTURE FROM THE GULF OF MEXICO WILL INCREASE ACROSS THE REGION THROUGH EARLY NEXT WEEK. RESTRICTIONS FROM STRATUS AND/OR FOG COULD DEVELOP DURING THE PRE/DAWN HOURS EACH MORNING ACROSS AREAS THAT RECEIVED RAIN THE PREVIOUS AFTERNOON OR EVENING. CONFIDENCE TABLE... 11-17Z 17-23Z 23-05Z 05-06Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 94% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 94% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...WIMBERLEY NEAR TERM...HG SHORT TERM...WIMBERLEY LONG TERM...WIMBERLEY AVIATION...HG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1250 PM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 1059 AM CDT SAT MAY 16 2015 MESSY DAY AHEAD AS A SMALL MCS EXITS TO THE NORTH LEAVING BEHIND EASTERLY FLOW IN THE FAR NORTHERN CWA. JET MAX LIFTING NORTH OVER THE WESTERN HIGH PLAINS WILL SWING THROUGH THE ENTRANCE REGION THIS AFTERNOON AND SOME EFFECTS OF THAT MAY ALREADY BE SHOWING UP. A SMALL POSSIBLE MCV IS LIFTING NORTH INTO NORTH CENTRAL NEBRASKA AND WILL LIFT THROUGH THE CWA EARLY THIS AFTERNOON. A HANDFUL OF THE HIGH RESOLUTION MODELS INDICATING SCATTERED THUNDERSTORMS POSSIBLE BETWEEN ABOUT THE JAMES RIVER AND INTERSTATE 29 AND SUSPECT IT IS ASSOCIATED WITH THIS FEATURE. NOT SURE HOW MUCH TO REALLY BITE ON THIS RIGHT NOW. IF THESE STORMS CAN DEVELOP AN ISOLATED SEVERE STORM WOULD BE POSSIBLE BUT WITH CAPE VALUES FAIRLY LOW...AROUND 1000 J/KG...MAINLY LOOKING AT QUARTERS AND 60 MPH WINDS. IF THIS SMALL MCV FEATURE DOES NOT SET ANY ACTIVITY OFF THE FLOW IS NOT REALLY CONVERGENT AT ALL AND WOULD EXPECT A BETTER CHANCE TO THE WEST OF OUR AREA AND OF COURSE TO THE SOUTH. THE ACTIVITY TO THE SOUTH WILL BE THE MOST IMPORTANT TO WATCH AS THAT WILL LIKELY ADVECT/DEVELOP NORTH THROUGH THE EVENING. AGAIN...INSTABILITY MARGINAL SO QUARTERS TO MAYBE HALF DOLLARS WILL BE THE MAIN THREAT. WILL ALSO NEED TO WATCH FOR A SMALL CHANCE FOR SOME FLASH FLOODING...ESPECIALLY FAR SOUTHEAST SD...NORTHWEST IA AND SOUTHWEST MN WHERE HEAVY RAIN HAS FALLEN AS OF LATE AND OR THE MODELS ARE HINTING AT SOME HIGHER RAINFALL POTENTIAL. THE 3 HOUR FLASH FLOOD GUIDANCE IN THESE LOCATIONS RUNNING GENERALLY LESS THAN 2 INCHES. WILL PROBABLY DECREASE POPS A BIT THIS AFTERNOON AND FOCUS BEST CHANCES AFTER ABOUT 2-4Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT SAT MAY 16 2015 TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND SEVERE STORM CHANCES LATER ON TODAY. SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE. COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR THIS AFTERNOON AND EVENING. EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE OVER AN INCH IS POSSIBLE THROUGH TONIGHT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 340 AM CDT SAT MAY 16 2015 STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH OF THE AREA. AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE 70S EAST TO THE 60S WEST. THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S. MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST. HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY THE END OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1246 PM CDT SAT MAY 16 2015 MVFR CEILINGS WILL LIFT NORTH THROUGH THE AFTERNOON...BUT MAY AGAIN REDEVELOP AFTER SUNSET AS MIXING DECREASES AND THE INVERSION STRENGTHENS AGAIN. BACKED OFF ON THUNDERSTORM CHANCES THIS AFTERNOON AND EVENING BUT WILL STILL BRING A GOOD CHANCES FOR THUNDERSTORMS THROUGH FROM ABOUT 4Z THROUGH 12Z. AT THIS TIME NOT EXPECTING MORE THAN ISOLATED SEVERE STORMS BUT THERE COULD BE QUITE A FEW STORMS CAPABLE OF LIGHTNING...SMALL HAIL AND HEAVY RAINFALL. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...08 SHORT TERM... LONG TERM... AVIATION...08
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1241 PM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 1159 AM CDT SAT MAY 16 2015 MUCH UNCERTAINTY OVER SEVERE WEATHER POTENTIAL THIS AFTERNOON THANKS MAINLY TO CLOUD COVER. WARM FRONT CONTINUES TO SLOWLY LIFT ACROSS THE CWA...PROVIDING A NARROW RIBBON OF FAVORABLE SEVERE WEATHER PARAMETERS...AND AS A FOCUS FOR AROUND 1000 J/KG CAPE. HOWEVER HRRR AND NSSL WRF TEND TO GENERATE SPOTTY CONVECTION ACROSS THE CWA IN THE AFTERNOON/EVENING...WHICH MAY BE AN ARTIFACT OF THE WEAK UPPER SUPPORT AND INHIBITION FROM CLOUD COVER. DESPITE THESE RESERVATIONS...LOW LEVEL SHEAR AND LOW LCLS SUPPORT CONTINUED MONITORING FOR A SEVERE WEATHER THREAT AND MENTION IN ZONE. THE MAIN SHORTWAVE LIFTING NORTH TOWARDS SUNDAY AM IS ASSOCIATED WITH THE BEST JET DYNAMICS...AND SREF PROBABILITIES FOR HEAVY RAIN ARE QUITE HIGH. && .SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON) ISSUED AT 435 AM CDT SAT MAY 16 2015 AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD! INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY. TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW" ACROSS WESTERN SD. IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500- 1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO. CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS APPEARS REASONABLE. SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST. .LONG TERM...(MONDAY EVENING THROUGH FRIDAY) ISSUED AT 435 AM CDT SAT MAY 16 2015 COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD. LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE. THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL BE OVER THE WEST/SOUTHWEST CWA. MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1231 PM CDT SAT MAY 16 2015 MAINLY VFR OR PERHAPS OCCASIONALLY MVFR CONDITIONS ON SOUTH/SOUTHEASTERLY WINDS WILL BE THE RULE OVER THE NEXT 12 HOURS AT LEAST. ANY CONVECTION WILL LIKELY KNOCK THAT DOWN INTO IFR RANGE DUE TO VISBY/CIG RESTRAINTS IN HEAVIER DOWNPOURS. CONVECTION TODAY/TONIGHT WILL HAVE THE ABILITY TO PRODUCE LARGE HAIL...DAMAGING WINDS AND PERHAPS EVEN A BRIEF TORNADO. LATER TONIGHT INTO SUNDAY...STRONG NORTH/NORTHWEST WINDS WILL DEVELOP OVER THE KPIR AND KMBG TERMINALS WHILE A BROAD BAND OF MODERATE TO OCCASIONALLY HEAVY RAIN SHOWERS AND EMBEDDED THUNDER LIFTS UP ACROSS THE REGION...LIKELY AFFECTING ALL FOUR TERMINALS AT SOME POINT HEADING INTO SUNDAY MORNING. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...CONNELLY SHORT TERM...FOWLE LONG TERM...TMT AVIATION...DORN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1224 PM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 1159 AM CDT SAT MAY 16 2015 MUCH UNCERTAINTY OVER SEVERE WEATHER POTENTIAL THIS AFTERNOON THANKS MAINLY TO CLOUD COVER. WARM FRONT CONTINUES TO SLOWLY LIFT ACROSS THE CWA...PROVIDING A NARROW RIBBON OF FAVORABLE SEVERE WEATHER PARAMETERS...AND AS A FOCUS FOR AROUND 1000 J/KG CAPE. HOWEVER HRRR AND NSSL WRF TEND TO GENERATE SPOTTY CONVECTION ACROSS THE CWA IN THE AFTERNOON/EVENING...WHICH MAY BE AN ARTIFACT OF THE WEAK UPPER SUPPORT AND INHIBITION FROM CLOUD COVER. DESPITE THESE RESERVATIONS...LOW LEVEL SHEAR AND LOW LCLS SUPPORT CONTINUED MONITORING FOR A SEVERE WEATHER THREAT AND MENTION IN ZONE. THE MAIN SHORTWAVE LIFTING NORTH TOWARDS SUNDAY AM IS ASSOCIATED WITH THE BEST JET DYNAMICS...AND SREF PROBABILITIES FOR HEAVY RAIN ARE QUITE HIGH. UPDATE ISSUED AT 647 AM CDT SAT MAY 16 2015 AVIATION DISCUSSION UPDATED BELOW FOR 12Z TAFS. && .SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON) ISSUED AT 435 AM CDT SAT MAY 16 2015 AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD! INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY. TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW" ACROSS WESTERN SD. IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500- 1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO. CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS APPEARS REASONABLE. SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST. .LONG TERM...(MONDAY EVENING THROUGH FRIDAY) ISSUED AT 435 AM CDT SAT MAY 16 2015 COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD. LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE. THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL BE OVER THE WEST/SOUTHWEST CWA. MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 647 AM CDT SAT MAY 16 2015 QUITE A VARIATION OF CONDITIONS THROUGH THE TAF FORECAST PERIOD. THIS MORNING...A MIX OF CIGS ACROSS THE REGION RANGING FROM AROUND 500 FT TO LOW END VFR CONDITIONS. ALSO SEEING SHRA AFFECTING KABR AND KATY BUT WILL BE ENDING BY 13Z. EXPECTING REDEVELOPMENT OF SHOWER AND STORM ACTIVITY BY AROUND 18Z AND PERSISTING THROUGH THE AFTERNOON ACROSS MUCH OF THE FORECAST AREA. HEAVIER STORMS MAY DROP CIGS INTO MVFR AND VSBY INTO IFR. SEVERE STORMS ARE POSSIBLE AS WELL AND COULD AFFECT TERMINALS WITH GUSTY SFC WINDS AND HAIL. LATE T0NIGHT...ANOTHER BATCH OF RAINFALL IS EXPECTED TO MOVE NORTHWARD INTO THE REGION. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...CONNELLY SHORT TERM...FOWLE LONG TERM...TMT AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1115 AM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 1059 AM CDT SAT MAY 16 2015 MESSY DAY AHEAD AS A SMALL MCS EXITS TO THE NORTH LEAVING BEHIND EASTERLY FLOW IN THE FAR NORTHERN CWA. JET MAX LIFTING NORTH OVER THE WESTERN HIGH PLAINS WILL SWING THROUGH THE ENTRANCE REGION THIS AFTERNOON AND SOME EFFECTS OF THAT MAY ALREADY BE SHOWING UP. A SMALL POSSIBLE MCV IS LIFTING NORTH INTO NORTH CENTRAL NEBRASKA AND WILL LIFT THROUGH THE CWA EARLY THIS AFTERNOON. A HANDFUL OF THE HIGH RESOLUTION MODELS INDICATING SCATTERED THUNDERSTORMS POSSIBLE BETWEEN ABOUT THE JAMES RIVER AND INTERSTATE 29 AND SUSPECT IT IS ASSOCIATED WITH THIS FEATURE. NOT SURE HOW MUCH TO REALLY BITE ON THIS RIGHT NOW. IF THESE STORMS CAN DEVELOP AN ISOLATED SEVERE STORM WOULD BE POSSIBLE BUT WITH CAPE VALUES FAIRLY LOW...AROUND 1000 J/KG...MAINLY LOOKING AT QUARTERS AND 60 MPH WINDS. IF THIS SMALL MCV FEATURE DOES NOT SET ANY ACTIVITY OFF THE FLOW IS NOT REALLY CONVERGENT AT ALL AND WOULD EXPECT A BETTER CHANCE TO THE WEST OF OUR AREA AND OF COURSE TO THE SOUTH. THE ACTIVITY TO THE SOUTH WILL BE THE MOST IMPORTANT TO WATCH AS THAT WILL LIKELY ADVECT/DEVELOP NORTH THROUGH THE EVENING. AGAIN...INSTABILITY MARGINAL SO QUARTERS TO MAYBE HALF DOLLARS WILL BE THE MAIN THREAT. WILL ALSO NEED TO WATCH FOR A SMALL CHANCE FOR SOME FLASH FLOODING...ESPECIALLY FAR SOUTHEAST SD...NORTHWEST IA AND SOUTHWEST MN WHERE HEAVY RAIN HAS FALLEN AS OF LATE AND OR THE MODELS ARE HINTING AT SOME HIGHER RAINFALL POTENTIAL. THE 3 HOUR FLASH FLOOD GUIDANCE IN THESE LOCATIONS RUNNING GENERALLY LESS THAN 2 INCHES. WILL PROBABLY DECREASE POPS A BIT THIS AFTERNOON AND FOCUS BEST CHANCES AFTER ABOUT 2-4Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT SAT MAY 16 2015 TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND SEVERE STORM CHANCES LATER ON TODAY. SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE. COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR THIS AFTERNOON AND EVENING. EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE OVER AN INCH IS POSSIBLE THROUGH TONIGHT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 340 AM CDT SAT MAY 16 2015 STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH OF THE AREA. AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE 70S EAST TO THE 60S WEST. THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S. MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST. HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY THE END OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 638 AM CDT SAT MAY 16 2015 BROAD AREA OF MVFR AND IFR CONDITIONS ACROSS THE FORECAST AREA THIS MORNING IN ADDITION TO SCATTERED TSRA TRACKING NORTHEAST THROUGH THE REGION. EXPECT THIS ACTIVITY TO CONTINUE TO WEAKEN AND DIMINISH THROUGH 15Z. MODELS SUGGEST THAT SOME IMPROVEMENT TO CEILINGS FROM SOUTH TO NORTH THROUGH MIDDAY. ADDITIONAL SHOWER AND THUNDERSTORMS DEVELOPMENT IS EXPECTED IN THE AFTERNOON...BECOMING MORE WIDESPREAD BY EVENING. TIMING IS A BIT DIFFICULT AT THIS POINT...BUT HAVE ADDED TSRA MENTION AND LOWER CEILINGS TO TAF SITES THIS EVENING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...08 SHORT TERM... LONG TERM... AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
656 AM CDT SAT MAY 16 2015 .UPDATE... ISSUED AT 647 AM CDT SAT MAY 16 2015 AVIATION DISCUSSION UPDATED BELOW FOR 12Z TAFS. && .SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON) ISSUED AT 435 AM CDT SAT MAY 16 2015 AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD! INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY. TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW" ACROSS WESTERN SD. IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500- 1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO. CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS APPEARS REASONABLE. SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST. .LONG TERM...(MONDAY EVENING THROUGH FRIDAY) ISSUED AT 435 AM CDT SAT MAY 16 2015 COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD. LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE. THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL BE OVER THE WEST/SOUTHWEST CWA. MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 647 AM CDT SAT MAY 16 2015 QUITE A VARIATION OF CONDITIONS THROUGH THE TAF FORECAST PERIOD. THIS MORNING...A MIX OF CIGS ACROSS THE REGION RANGING FROM AROUND 500 FT TO LOW END VFR CONDITIONS. ALSO SEEING SHRA AFFECTING KABR AND KATY BUT WILL BE ENDING BY 13Z. EXPECTING REDEVELOPMENT OF SHOWER AND STORM ACTIVITY BY AROUND 18Z AND PERSISTING THROUGH THE AFTERNOON ACROSS MUCH OF THE FORECAST AREA. HEAVIER STORMS MAY DROP CIGS INTO MVFR AND VSBY INTO IFR. SEVERE STORMS ARE POSSIBLE AS WELL AND COULD AFFECT TERMINALS WITH GUSTY SFC WINDS AND HAIL. LATE T0NIGHT...ANOTHER BATCH OF RAINFALL IS EXPECTED TO MOVE NORTHWARD INTO THE REGION. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...TMT SHORT TERM...FOWLE LONG TERM...TMT AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
649 AM CDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT SAT MAY 16 2015 TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND SEVERE STORM CHANCES LATER ON TODAY. SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE. COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR THIS AFTERNOON AND EVENING. EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE OVER AN INCH IS POSSIBLE THROUGH TONIGHT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 340 AM CDT SAT MAY 16 2015 STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH OF THE AREA. AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE 70S EAST TO THE 60S WEST. THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S. MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST. HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY THE END OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 638 AM CDT SAT MAY 16 2015 BROAD AREA OF MVFR AND IFR CONDITIONS ACROSS THE FORECAST AREA THIS MORNING IN ADDITION TO SCATTERED TSRA TRACKING NORTHEAST THROUGH THE REGION. EXPECT THIS ACTIVITY TO CONTINUE TO WEAKEN AND DIMINISH THROUGH 15Z. MODELS SUGGEST THAT SOME IMPROVEMENT TO CEILINGS FROM SOUTH TO NORTH THROUGH MIDDAY. ADDITIONAL SHOWER AND THUNDERSTORMS DEVELOPMENT IS EXPECTED IN THE AFTERNOON...BECOMING MORE WIDESPREAD BY EVENING. TIMING IS A BIT DIFFICULT AT THIS POINT...BUT HAVE ADDED TSRA MENTION AND LOWER CEILINGS TO TAF SITES THIS EVENING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM... LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
441 AM CDT SAT MAY 16 2015 .SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON) ISSUED AT 435 AM CDT SAT MAY 16 2015 AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD! INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY. TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW" ACROSS WESTERN SD. IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500- 1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO. CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS APPEARS REASONABLE. SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST. .LONG TERM...(MONDAY EVENING THROUGH FRIDAY) ISSUED AT 435 AM CDT SAT MAY 16 2015 COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD. LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE. THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL BE OVER THE WEST/SOUTHWEST CWA. MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 435 AM CDT SAT MAY 16 2015 TWO WAVES OF SHOWERS AND THUNDERSTORMS ARE EXPECTED TO AFFECT ALL TERMINALS TONIGHT AND AGAIN SATURDAY AFTERNOON. A STRONG WARM FRONT/LLJ SURGING NORTH ALONG WITH AN UPPER LEVEL TROUGH/JET STREAK WILL CONTINUE TO SPREAD THE FIRST ROUND OF SHOWERS AND THUNDERSTORMS ACROSS ALL OF THE AREA INTO SATURDAY MORNING. EXPECT MAINLY MVFR CEILINGS AND VISIBILITIES TONIGHT. THE RAIN AND STRATUS ARE EXPECTED TO LIFT NORTH WHILE NEW SHOWER AND THUNDERSTORM DEVELOPMENT IS EXPECTED SATURDAY AFTERNOON. SOME OF THESE COULD BE SEVERE. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...FOWLE LONG TERM...TMT AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
340 AM CDT SAT MAY 16 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT SAT MAY 16 2015 TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND SEVERE STORM CHANCES LATER ON TODAY. SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE. COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR THIS AFTERNOON AND EVENING. EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE OVER AN INCH IS POSSIBLE THROUGH TONIGHT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 340 AM CDT SAT MAY 16 2015 STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH OF THE AREA. AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE 70S EAST TO THE 60S WEST. THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S. MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST. HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY THE END OF THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1107 PM CDT FRI MAY 15 2015 CURRENTLY...MVFR TO VFR CONTINUES TO DOMINATE THE SIOUX FALLS FORECAST AREA. MOST OF THE MVFR IS BOTTLED UP ALONG AND NORTH OF I 90 WITH PRIMARILY VFR SOUTH OF I 90. OVERALL CONFIDENCE IS LOW WITH THE 06Z SET OF TAFS WITH THE DETAILS. MODELS INCLUDING THE LATEST NAM/GFS AND GEM REGIONAL CONTINUE TO SHOW A LOT OF LOW LEVEL HUMIDITY BUILDING BACK IN BETWEEN 06Z AND 12Z TONIGHT BUT HOW MUCH OF THIS IS BELIEVABLE REMAINS TO BE SEEN. TAKEN LITERALLY...ALL OF THE TAF SITES WOULD GO IFR IF NOT LIFR BY 09Z OR 10Z SATURDAY. WITH A RELATIVELY DRY EAST TO SOUTHEAST FLOW OF AIR AM NOT BUYING THAT TOTALLY...AND OPTED TO HEDGE AND PUT IN MVFR INSTEAD FOR NOW. THERE COULD BE ONE BAND OF RAIN MOVING THROUGH SOUTHEAST SD AND EAST CENTRAL SD EARLY SATURDAY MORNING...AND AGAIN ACROSS PARTS OF THE AREA LATE SATURDAY AFTERNOON. FOR NOW...LEFT OUT THE MENTION OF THUNDERSTORMS AS ELEVATED INSTABILITY IS ABUNDANT...BUT REMAINS TOO SKITTISH TO MENTION AT A POINT LOCATION. AND A BULK OF THE ORGANIZED RAINFALL WHEN THERE WILL BE THUNDERSTORMS FOR SURE DOES NOT OCCUR UNTIL IT IS ON SIOUX CITY`S DOORSTEP TOWARD THE END OF THE TAF PERIOD. SO AGAIN...LEFT IT OUT FOR NOW. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM... LONG TERM... AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1109 PM CDT FRI MAY 15 2015 .UPDATE... ISSUED AT 914 PM CDT FRI MAY 15 2015 UPDATED EARLIER THIS EVENING TO REDUCE THE CHANCES FOR RAIN AND STORMS THROUGH THE OVERNIGHT HOURS TO SLIGHT CHANCE OR NONE. HOWEVER AM RELUNCTANT TO RADICALLY ALTER SHOWER AND THUNDERSTORM CHANCES LATE TONIGHT AS THE HRRR AND NOW THE NEW NAM12 SHOW SOME DEVELOPMENT ARCING THROUGH IN A NORTHWEST TO SOUTHEAST BAND. THIS OCCURS LATE TONIGHT AND EARLY SATURDAY ALONG AN ELEVATED WARM FRONT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 414 PM CDT FRI MAY 15 2015 DEEP UPPER TROUGHING OVER THE SOUTHWESTERN UNITED STATES CONTINUES TO POUR MOISTURE NORTHWARD INTO THE PLAINS THIS AFTERNOON. HOWEVER...FOCUS FOR CONVECTION HAS BEEN SPLIT THROUGH MUCH OF THE DAY...WITH MCV LIFTING NORTHWARD THROUGH WESTERN SD AND A SECONDARY SHORTWAVE DRIVING CONVECTION IN THE MID/LOWER MISSOURI RIVER VALLEY. OVERHEAD...WEAK ISENTROPIC ASSENT TIED NEAR THE 305K SFC CONTINUES TO PRODUCE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. HEADING INTO THE LATE AFTERNOON AND EVENING HOURS...MAIN FOCUS TURNS TO WESTERN NE/SD AS UPPER JET BEGINS TO NOSE INTO THE PLAINS. ALREADY A WELL DEVELOPED WARM FRONT STRETCHING ACROSS PORTIONS OF NEBRASKA...BUT THE REINFORCING ELEVATED CONVECTION HAS KEPT THIS BOUNDARY SW OF THE CWA THROUGH THE DAY. WITH 850:700 MB FLOW BEGINNING TO BACK INTO THE WESTERN PLAINS ONGOING SHOWER ACTIVITY IN THE LOCAL AREA MAY BEGIN TO WANE AS EVENING APPROACHES WITH CONVECTION OVER NEBRASKA PANHANDLE TAKING OFF. WITH THE SFC WARM FRONT TRYING TO REACH THE NE/SD LINE IN SOUTH CENTRAL SD...AN ISOLATED STORM MAY STILL BE POSSIBLE EARLY THIS EVENING NEAR THE MISSOURI RIVER. THROUGH THE OVERNIGHT HOURS...LATEST HIGH RES GUIDANCE HINTS AT SEVERAL CLUSTERS OF STORMS LIFTING NORTHEAST ACROSS NE/SD OVERNIGHT. AS THE LEAD SHORTWAVE ENTERS THE PLAINS LATE THIS EVENING...WE MAY BEGIN TO SEE THE LLJ VEER SOUTHWESTERLY WHICH COULD REIGNITE ADDITIONAL ELEVATED CONVECTION FURTHER SOUTHEAST THROUGH CENTRAL NEBRASKA AND SOUTH CENTRAL SD ALONG ELEVATED BOUNDARY LIFTING NORTHEAST. INSTABILITY WOULD BE WANING AT THIS POINT...BUT COULD BE DEALING WITH MARGINAL HAIL OR PERHAPS BRIEF WIND GUSTS GIVEN PARALLEL ORIENTATION OF LOW LVL FLOW. THIS STRONGER STORM RISK WOULD MAINLY BE WEST OF THE JAMES RIVER INTO THE EARLY MORNING HOURS...HOWEVER THE RISK OF CONVECTION COULD SPREAD ALL THE WAY EASTWARD INTO WESTERN MN. FOR SATURDAY...A VERY TRICKY FORECAST REMAINS. DEEP MERIDIONAL FLOW IS EXPECTED TO FURTHER ENHANCE MOISTURE OVERNIGHT INTO THE AREA...WITH LLJ KEEPING ELEVATED CONVECTION LINGERING OVER THE CWA INTO EARLY SATURDAY MORNING. A MUCH STRONGER WAVE WILL PIVOT INTO THE PLAINS SATURDAY AFTERNOON. THE BIGGEST QUESTION FOR SATURDAY...GIVEN THE DEEP MERIDIONAL FLOW...IS THE DEGREE OF CLOUD COVER AND INSTABILITY THAT CAN GROW THROUGH THE AFTERNOON. THERE ARE SOME HINTS THAT LINGERING CLOUD COVER AND ELEVATED SHOWERS MAY WORK TO REINFORCE THE EML IN THE AFTERNOON...WITH MODELS HINTING AT A WEAK SHORTWAVE RACING NORTHWARD AND THROUGH THE AREA BY MID-DAY SATURDAY. HOWEVER...THE BEST CHANCE FOR ANY MORE SUBSTANTIAL GROWTH IN SFC BASED INSTABILITY WILL BE ALONG A NORTH-SOUTH ORIENTATED SFC BOUNDARY ACROSS WEST CENTRAL SD/NE. THAT SAID...CANNOT RULE OUT A FEW STRONG STORM CLUSTERS...MAINLY BOWING SEGMENTS FURTHER EAST...ESPECIALLY IF STRONGER POCKETS OF INSTABILITY CAN GROW GIVEN THE UNIDIRECTIONAL FLOW AND DECENT SPEED SHEAR ALOFT. AGAIN...VERY CONDITIONAL AND UNCERTAIN. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 414 PM CDT FRI MAY 15 2015 THE CHANCE FOR THUNDERSTORMS WILL INCREASE RAPIDLY SATURDAY EVENING AS A STRONG SHORT WAVE TROUGH AND JET STREAK MOVE NORTHWARD INTO SOUTH DAKOTA. EXPECTED SCENARIO AT THIS TIME IS THAT THUNDERSTORM COVERAGE WILL SLOWLY INCREASE THROUGH THE EVENING AS WAVE APPROACHES WITH A CLUSTER OF SHOWERS AND THUNDERSTORMS MOVING INTO THE MISSOURI VALLEY AROUND SUNSET AND REACHING I90 BEFORE MIDNIGHT. WITH ALMOST NO CAPPING INVERSION...THESE SHOWERS AND STORMS WILL CONTINUE DEVELOP AND MOVE NORTHEAST THROUGH THE NIGHT. WITH WIDESPREAD STORMS...SEVERE WEATHER IS UNLIKELY EXCEPT AHEAD OF THE MAIN CLUSTER OF STORMS IN THE EVENING...ASSUMING ENOUGH INSTABILITY IS PRESENT TO PRODUCE A STRONG ENOUGH UPDRAFT TO SUPPORT MARGINALLY SEVERE HAIL. AS NOTED ABOVE...THIS THREAT IS VERY CONDITIONAL AND UNCERTAIN AS CAPES BY EVENING WILL LIKELY BE AT OR BELOW 1000 J/KG. INSTEAD EXPECTING A WIDESPREAD 0.5 TO 1.0 INCH OF RAIN SATURDAY NIGHT. LOCAL AMOUNTS COULD EXCEED 1.5 INCHES IN PORTIONS OF THE AREA. WITH THE CLOUDS AND PRECIPITATION LOWS WILL BE AROUND 60. ON SUNDAY...SHOWERS AND STORMS WILL LINGER INTO THE MORNING...ESPECIALLY NORTH OF I90. THEN A DRY SLOT WILL MOVE OVER THE AREA WHICH SHOULD BRING A RESPITE TO THE PRECIPITATION TO MOST AREA. A DRY LINE IS THEN EXPECTED TO MOVE ACROSS THE AREA ON SUNDAY MORNING. AT THIS POINT...HAVE LOW POPS WITH THE DRY LINE AS UPPER FORCING FOR ASCENT IS MINIMAL AND ATMOSPHERE WILL BE FAIRLY STABLE FOLLOWING THE OVERNIGHT CONVECTION. A COLD FRONT WILL MOVE ACROSS SUNDAY AFTERNOON. WITH LIMITED MOISTURE... PRECIPITATION WILL NOT BE AS WIDESPREAD AND IS EXPECTED TO BE FOCUSED CLOSER TO THE UPPER LOW MOVING ACROSS CENTRAL SD AND EASTERN ND. SO HAVE THE HIGHEST POPS NORTH OF INTERSTATE 90. WHILE THUNDER IS POSSIBLE WITH ANY STORMS...WITH THE LIMITED INSTABILITY AND MOISTURE...HAVE PRIMARILY RAIN SHOWERS WITH A LOWER PROBABILITY OF THUNDER. HIGHS WILL BE IN THE MID 70S WHERE THE COLD FRONT WILL MOVE THROUGH IN THE LATE AFTERNOON...WITH MID 60S IN CENTRAL SOUTH DAKOTA WHERE THERE WILL BE MORE CLOUDS AND MUCH EARLY COLD FRONTAL PASSAGE. FROM SUNDAY AFTERNOON INTO MONDAY EVENING...THE FOCUS WILL SHIFT FOR RAIN TO WIND AND COLD. ONCE THE COLD FRONT MOVES THROUGH SUNDAY AFTERNOON...NORTHWEST WIND WILL REALLY INCREASE WITH GUSTS WELL ABOVE 30 MPH BY SUNDAY EVENING. WINDS WILL DROP LITTLE ON SUNDAY NIGHT AND THEN PICK BACK UP WITH SUSTAINED WINDS OVER 20 MPH ON MONDAY. TEMPERATURES WILL FALL FAIRLY QUICKLY SUNDAY NIGHT WITH LOWS IN THE 30S TO LOW 40S. ON MONDAY...THERE WILL BE A LOT OF LOW LEVEL MOISTURE AROUND SO EVEN IF THERE IS SOME BREAKS IN CLOUDS MONDAY MORNING...WITH 850 MB TEMPS BELOW ZERO...SUNSHINE WILL BE SELF DESTRUCTIVE AND SKIES IN MOST AREA WILL BECOME CLOUDY BY LATE MORNING. MOST PLACES WILL LIKELY REACH HIGHS IN THE 40S TO MID 50S BY EARLY AFTERNOON AND THEN HOLDING STEADY. AT THIS POINT THE GFS BUFR SOUNDINGS SHOW A VERY SHALLOW UNSTABLE LAYER SO NOT EXPECTING SHOWERS TO DEVELOP BUT WILL NEED TO MONITOR THE POTENTIAL AS NAM/ECMWF SOUNDINGS WOULD SUPPORT A MIX OF GRAUPAL AND RAIN IN PORTIONS OF SW MN AND EAST CENTRAL SD. IN THE LONGER RANGE...MONDAY NIGHT THROUGH FRIDAY...BELOW NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE. THE MODELS HAVE A GENERAL AGREEMENT WITH A LONG WAVE TROUGH OVER THE AREA THROUGH THE WEEK. THE BEST CHANCE OF RAIN WILL BE ON LATE TUESDAY NIGHT AND WEDNESDAY BUT THERE IS SOME QUESTION HOW FAR EAST THE RAIN WILL GET AS EASTERLY FLOW FROM HIGH PRESSURE WILL ACT TO LIMIT MOISTURE FLOW INTO THE AREA AND MAY PREVENT RAIN FROM REACHING SW MN AND PORTIONS OF NW IA. TEMPERATURES THROUGH WEDNESDAY WILL BE IN THE 50S WITH UNSEASONABLY COLD AIR BOTH DAYS AND CLOUDS AND RAIN ON WEDNESDAY. A GRADUAL WARM UP WILL BEGIN ON THURSDAY AND CONTINUE INTO FRIDAY ALTHOUGH IT IS MOST LIKELY HIGHS WILL REMAIN IN THE 60S. A STRONGER WAVE WILL ALSO APPROACH LATER FRIDAY WHICH MAY BRING A CHANCE OF THUNDERSTORMS BY AFTERNOON. HOWEVER...THE BETTER CHANCE WILL BE INTO MEMORIAL DAY WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1107 PM CDT FRI MAY 15 2015 CURRENTLY...MVFR TO VFR CONTINUES TO DOMINATE THE SIOUX FALLS FORECAST AREA. MOST OF THE MVFR IS BOTTLED UP ALONG AND NORTH OF I 90 WITH PRIMARILY VFR SOUTH OF I 90. OVERALL CONFIDENCE IS LOW WITH THE 06Z SET OF TAFS WITH THE DETAILS. MODELS INCLUDING THE LATEST NAM/GFS AND GEM REGIONAL CONTINUE TO SHOW A LOT OF LOW LEVEL HUMIDITY BUILDING BACK IN BETWEEN 06Z AND 12Z TONIGHT BUT HOW MUCH OF THIS IS BELIEVABLE REMAINS TO BE SEEN. TAKEN LITERALLY...ALL OF THE TAF SITES WOULD GO IFR IF NOT LIFR BY 09Z OR 10Z SATURDAY. WITH A RELATIVELY DRY EAST TO SOUTHEAST FLOW OF AIR AM NOT BUYING THAT TOTALLY...AND OPTED TO HEDGE AND PUT IN MVFR INSTEAD FOR NOW. THERE COULD BE ONE BAND OF RAIN MOVING THROUGH SOUTHEAST SD AND EAST CENTRAL SD EARLY SATURDAY MORNING...AND AGAIN ACROSS PARTS OF THE AREA LATE SATURDAY AFTERNOON. FOR NOW...LEFT OUT THE MENTION OF THUNDERSTORMS AS ELEVATED INSTABILITY IS ABUNDANT...BUT REMAINS TOO SKITTISH TO MENTION AT A POINT LOCATION. AND A BULK OF THE ORGANIZED RAINFALL WHEN THERE WILL BE THUNDERSTORMS FOR SURE DOES NOT OCCUR UNTIL IT IS ON SIOUX CITY`S DOORSTEP TOWARD THE END OF THE TAF PERIOD. SO AGAIN...LEFT IT OUT FOR NOW. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...MJ SHORT TERM...DUX LONG TERM...SCHUMACHER AVIATION...MJ
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
856 PM CDT SUN MAY 17 2015 .DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES INDICATE A MESOSCALE CONVECTIVE VORTEX /MCV/ OVER LOUISIANA. THIS MCV ALONG WITH A SUBTLE 700 MB SHORTWAVE TROUGH OVER THE LOWER MISSISSIPPI HAD RESULTED IN ADDITIONAL SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS THE MID SOUTH THIS EVENING...MAINLY WEST OF THE MISSISSIPPI RIVER. AS OF 8 PM CDT...TEMPERATURES ACROSS THE MID SOUTH ARE IN THE LOWER 70S AT MOST LOCATIONS. LATEST HRRR ALONG WITH THE 00Z WRF INDICATE POTENTIAL FOR RE- DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE MID SOUTH OVERNIGHT. WILL MAKE SOME ADJUSTMENTS TO POPS AND ALL OTHER ELEMENTS AS NEEDED FOR THE REMAINDER OF THE NIGHT. UPDATED GRIDS WILL BE AVAILABLE SHORTLY. CJC && .PREV DISCUSSION... /ISSUED 639 PM CDT SUN MAY 17 2015/ UPDATE...AVIATION DISCUSSION. PREV DISCUSSION... /ISSUED 304 PM CDT SUN MAY 17 2015/ THE MIDSOUTH REMAINS STUCK UNDERNEATH SOUTHWEST FLOW ALOFT. THE SOUTHWEST FLOW ALOFT HAS BROUGHT THIS WET PATTERN TO THE REGION AS THE COMBINATION OF SHORTWAVES MOVING THROUGH THE FLOW AND AN ABUNDANCE OF MOISTURE FROM THE GULF OF MEXICO HAS PRODUCED ROUND AFTER ROUND OF SHOWERS AND THUNDERSTORMS. LOOKING AT LATEST RADAR IMAGES...MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY HAS NOW PUSHED EAST OF THE MISSISSIPPI RIVER. MOST OF THIS CONVECTION WILL LIKELY PUSH EAST OF THE CWA BY 7 PM. HOWEVER...LATEST HRRR SHOWS REDEVELOPMENT OCCURRING OVER NORTHEAST ARKANSAS BY THAT TIME. THE CORRIDOR FROM NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL MAY SEE MOST OF THE CONVECTION DURING THE LATE EVENING INTO THE OVERNIGHT HOURS BEFORE IT SHIFTS SOUTHWARD ON MONDAY. HAVE ADJUSTED POPS ACCORDINGLY. IN ADDITION...SINCE THERE ARE PORTIONS OF NORTHEAST MISSISSIPPI THAT HAS SEEN SEVERAL ROUNDS OF HEAVY SHOWERS TODAY...WILL GO AHEAD AND EXPAND THE FLASH FLOOD WATCH SOUTHWARD TO COVER THE ENTIRE CWA THROUGH MONDAY. MONDAY WILL BE ANOTHER RAINY DAY FOR THE MIDSOUTH WITH OFF AND ON PERIODS OF HEAVY SHOWERS AND THUNDERSTORMS. EXPECT HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLD FRONT WILL FINALLY BEGIN TO PUSH INTO THE AREA MONDAY NIGHT INTO TUESDAY. MODELS ARE COMING INTO TO CLOSER AGREEMENT THAT THE FRONT WILL STALL OUT JUST SOUTH OF THE CWA AND BEGIN LIFTING BACK NORTHWARD AS A WARM FRONT LATE TUESDAY NIGHT INTO WEDNESDAY. THIS WILL KEEP SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR PORTIONS OF EAST-CENTRAL ARKANSAS AND NORTH MISSISSIPPI WHILE GIVING THE REST OF THE CWA ONLY A BRIEF REPRIEVE ON TUESDAY NIGHT. BY WEDNESDAY...THE ENTIRE MIDSOUTH WILL SEE CHANCES FOR SHOWERS AND THUNDERSTORMS AGAIN AS A WEAK SHORTWAVE MOVES ACROSS THE CWA. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL COME WEDNESDAY NIGHT INTO THURSDAY AS THE FRONT MOVES BACK THROUGH THE AREA AS A COLD FRONT. HIGH PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT THROUGH SATURDAY. NO PRECIPITATION IS EXPECTED AS A RESULT. HIGHS WILL BE IN THE MID 70S TO LOWER 80S. LOWS WILL BE IN THE MID 50S TO LOWER 60S. LOOKS LIKE THE MIDSOUTH COULD BE UNDERNEATH SOUTHWEST FLOW ALOFT AGAIN BY SATURDAY NIGHT CONTINUING INTO EARLY NEXT WEEK. THIS COULD BRING ANOTHER EXTENDED WET PERIOD TO THE REGION. KRM && .AVIATION... 00Z TAFS MORE OF THE SAME OVER THE NEXT 24 HOURS....ALTHOUGH THIS LOOKS LIKE THE END OF SEVERAL DAYS OF DEALING WITH STORMS. PERIODS OF THUNDERSTORMS WILL RESULT IN BRIEF IFR VIS AND VARIABLE GUSTY WINDS. A LINE OF THUNDERSTORMS IS DEVELOPING OVER EAST ARKANSAS AND COULD IMPACT JBR BY 1-2Z. DID NOT INCLUDE TS AT MEM...BUT THAT MAY NEED TO BE ADDED BASED ON RADAR TRENDS OVER THE NEXT COUPLE OF HOURS. ARRIVAL WOULD LIKELY BE 3-4Z. SHORT RANGE MODELS INDICATE ANOTHER YET ROUND OF TSRAS WILL FIRE UP AFTER MIDNIGHT...SHIFTING ACROSS JBR...MEM...AND MKL PRIOR TO SUNRISE. MODELS DISAGREE ON HOW WIDESPREAD LOW CLOUDS LATER TONIGHT AND MON MORNING. BEST CHANCES APPEAR TO BE AT KTUP AND PLACED A MVFR CIG THERE MONDAY MORNING OTRW WILL GO WITH OPTIMISTIC FORECAST. ANOTHER ROUND OF DAYTIME HEATING DRIVEN STORMS IS EXPECTED TOMORROW. WILL CARRY TEMPO TSRA AT ALL SIDES FOR MOST OF THE AFTERNOON. SOUTH WINDS 10-12 KTS WITH HIGHER GUSTS THIS AFTN...8-10 KTS TONIGHT. WINDS SHOULD BEGIN TO SHIFT MORE WESTERLY OR NORTHWESTERLY BY SUNSET TOMORROW...AND PRECIPITATION SHOULD COME TO AN END. 30 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR CLAY-CRAIGHEAD- CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI- PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS. MO...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR DUNKLIN-PEMISCOT. MS...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR ALCORN-BENTON MS- CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS- MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN- TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA. TN...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR BENTON TN-CARROLL- CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN- HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON- MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
311 PM CDT SAT MAY 16 2015 .DISCUSSION... POPCORN TYPE SHOWERS AND THUNDERSTORMS ARE OCCURRING ACROSS THE MIDSOUTH AND SURROUNDING AREAS. LATEST HRRR SHOWS THIS ACTIVITY CONTINUING THROUGH AROUND 7-8 PM. THEREAFTER...ACTIVITY WILL DISSIPATE FROM THE LOSS OF DAYTIME HEATING. EXPECT THE REMAINDER OF THE NIGHT TO BE TRANQUIL. WILL LEAVE 30 POPS IN CASE A STRAY SHOWER OR THUNDERSTORM DEVELOPS. LOWS WILL BE IN THE MID TO UPPER 60S. A SEVERE LINE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP THIS EVENING ACROSS OKLAHOMA...KANSAS...AND TEXAS. MODELS HAVE BEEN PRETTY CONSISTENT WITH BRINGING THE REMNANTS OF THIS LINE INTO EASTERN ARKANSAS AROUND SUNRISE. STILL EXPECT THE LINE TO BE IN THE DYING PHASES AS IT MOVES IN. THE LINE WILL FALL APART AS IT REACHES THE MS RIVER DURING THE MORNING. HOWEVER...REDEVELOPMENT ALONG LEFTOVER BOUNDARIES WILL BE POSSIBLE ALONG AND EAST OF THE MISSISSIPPI RIVER FROM MID-MORNING ON SUNDAY INTO THE AFTERNOON HOURS. EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DIE OUT AGAIN BY 7PM SUNDAY EVENING. NEW DEVELOPMENT MAY OCCUR ALONG AND WEST OF THE MISSISSIPPI RIVER DURING THE LATE EVENING TO OVERNIGHT HOURS AS A SHORTWAVE MOVES INTO THE REGION. THIS ACTIVITY WILL BLOSSOM OVER THE CWA INTO MONDAY. THE COLD FRONT IS STILL EXPECTED TO MOVE INTO THE AREA MONDAY NIGHT INTO TUESDAY. SCATTERED CHANCES FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE ALONG AND AHEAD OF THE FRONT. THE ECMWF AND GFS DIFFER ON HOW FAR SOUTH THE FRONT WILL PROGRESS. IF THE ECMWF IS CORRECT...TUESDAY NIGHT MAY BE THE ONLY DRY PERIOD BEFORE THE FRONT MOVES BACK NORTH AS A WARM FRONT. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL OCCUR ALONG AND AHEAD OF THE WARM FRONT. THE FRONT WILL RETURN SOUTHWARD AS A COLD FRONT ON THURSDAY. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL LIKELY OCCUR ON THURSDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA ON FRIDAY. && .AVIATION... 18Z TAFS WIDESPREAD MVFR CIGS ACROSS THE MIDSOUTH THIS MORNING WILL GRADUALLY LIFT TO VFR THIS AFTERNOON. SCATTERED SHRA AND TSRAS EXPECTED ACROSS THE REGION AND WILL CONTINUE VCTS AT ALL TERMINALS THROUGH EARLY EVENING. COVERAGE WILL DIMINISH WILL LOSS OF HEATING THIS EVENING. QUIET OVERNIGHT THEN LOW CLOUDS SHOULD REDEVELOP LATER TONIGHT INTO EARLY SUNDAY...ESPECIALLY AT KJBR AND KTUP. A WEAKENING LINE OF SHRAS AND TSRAS WILL BE PUSHING INTO THE MIDSOUTH SUNDAY MORNING. SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER GUSTS THIS AFTERNOON AT MEM AND KJBR. SJM && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
102 PM CDT SAT MAY 16 2015 .DISCUSSION... UPDATED FOR 18Z AVIATION DISCUSSION && .PREV DISCUSSION... /ISSUED 1049 AM CDT SAT MAY 16 2015/ UPDATE... AN AREA OF SHOWERS CONTINUE TO MOVE NORTH OVER PORTIONS OF WEST TENNESSEE...NORTHEAST ARKANSAS...AND THE MISSOURI BOOTHEEL. THIS AREA SHOULD MOVE INTO KENTUCKY AND MISSOURI BETWEEN 12-1 PM. MEANWHILE...DRY CONDITIONS ARE CURRENTLY OCCURRING OVER NORTH MISSISSIPPI. THE LATEST HRRR SHOWS ADDITIONAL DEVELOPMENT OCCURRING ACROSS SOUTHERN MISSISSIPPI THAT WILL MOVE INTO NORTH MISSISSIPPI AROUND 2 PM. THE CONVECTION WILL EVENTUALLY SPREAD INTO THE REST OF THE MIDSOUTH BETWEEN 3-5 PM. FORECAST LOOKS GOOD...NO UPDATES ARE EXPECTED. KRM DISCUSSION... /ISSUED 430 AM CDT SAT MAY 16 2015/ A WET DAY IS IN STORE FOR THE MIDSOUTH TODAY...FINALLY SEEMS MORE LIKE MAY ACROSS THE MIDSOUTH THAN WHAT WE HAVE EXPERIENCED THROUGH MUCH OF THE FIRST HALF OF THE MONTH. AREAS OF RAIN AND A FEW THUNDERSTORMS WERE ALREADY OCCURRING ACROSS THE MIDSOUTH EARLY THIS MORNING. THE WET PATTERN WILL CONTINUE INTO MONDAY AND WILL NEED TO MONITOR FOR THE POSSIBILITY OF FLOODING / FLASH FLOODING AS RAINFALL AMOUNTS INCREASE OVER TIME THROUGH THE WEEKEND INTO MONDAY. A LARGE UPPER LEVEL LOW WAS LOCATED OVER THE WESTERN UNITED STATES WITH AN UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST. A SOUTHERLY WIND FLOW BETWEEN THESE TWO SYSTEMS WAS PUSHING ABUNDANT MOISTURE INTO THE MIDSOUTH FROM THE GULF OF MEXICO. AN UPPER LEVEL SHORT WAVE WAS LOCATED OVER EAST TX AND WILL MOVE NORTHEASTWARD THROUGH THE MIDSOUTH TODAY. OCCASIONAL SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY. PRECIPITABLE WATER VALUES WILL BE BETWEEN 1.8 AND 2.0 INCHES WITH SURFACE DEW POINTS IN THE MIDDLE 60S TO NEAR 70 DEGREES. AS A RESULT...LOCALLY HEAVY RAINFALL MAY RESULT IN FLOODING IN SOME LOCATIONS TODAY...BUT NOT CONFIDENT ENOUGH THAT WILL BE WIDESPREAD ENOUGH FOR A FLASH FLOOD WATCH ATTM. DID MENTION THE THREAT OF LOCALLY HEAVY RAINFALL AND FLOODING IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. INSTABILITY LOOKS TO BE A LITTLE LESS THAN YESTERDAY WITH MORE WIDESPREAD RAIN AND CLOUDS. FOR TONIGHT...AN UPPER LEVEL TROUGH MOVES INTO THE CENTRAL PLAINS WITH AN ASSOCIATED COLD FRONT STRETCHING FROM KS INTO TX. ORGANIZED CONVECTION IS EXPECTED TO DEVELOP AHEAD OF THIS FRONT THROUGH THE PLAINS PERHAPS APPROACHING NORTHEAST ARKANSAS LATE TONIGHT...ALTHOUGH INSTABILITY DECREASING BY THAT TIME. WEAK UPPER LEVEL DISTURBANCES EMBEDDED IN SOUTHWEST FLOW ALOFT WILL CONTINUE THE THREAT FOR SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT ACROSS THE MIDSOUTH. SUNDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR WITH LOCALLY HEAVY RAINFALL A CONTINUING THREAT. THE UPPER LEVEL TROUGH WILL PUSH TO THE NORTHEAST THROUGH THE CENTRAL PLAINS WITH THE ASSOCIATED COLD FRONT REMAINING TO OUR WEST AND NORTH. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE TO OUR NORTH. 0-6 KM BULK SHEAR VALUES ARE ONLY MARGINAL FOR ORGANIZED SHEAR WEATHER NEAR EXTREME NORTHEAST ARKANSAS AND THE MO BOOTHEEL. HOWEVER... WIND FIELDS WILL BE STRONGER ACROSS THE MIDSOUTH SUNDAY AS THE UPPER LEVEL TROUGH MOVES TO OUR NORTH. THIS WILL ALLOW WARMER SURFACE TEMPERATURES TO PUSH INTO THE MIDSOUTH CAUSING GREATER INSTABILITY AND THE POSSIBILITY A FEW STRONG TO SEVERE THUNDERSTORMS. IF ANY SEVERE THUNDERSTORMS DO DEVELOP...DAMAGING WIND AND LARGE HAIL WOULD BE THE GREATEST SEVERE WEATHER THREATS. A COLD FRONT WILL SAG INTO THE MIDSOUTH FROM THE NORTH MONDAY AS THE UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST WEAKENS SOME WITH LOWERING UPPER LEVEL HEIGHTS ACROSS THE MIDSOUTH. WILL ONCE AGAIN NEED TO MONITOR FOR HEAVY RAINFALL AND FLOODING / FLASH FLOODING. THE COLD FRONT WILL GRADUALLY PUSH THROUGH THE MIDSOUTH MONDAY NIGHT AND TUESDAY WITH DECREASING CHANCES FOR RAIN FROM THE NORTH. TEMPERATURES WILL BE A LITTLE COOLER WITH PASSAGE OF THE COLD FRONT. FOR THE REMAINDER OF THE WORK WEEK...THE ECMWF AND GFS ARE NOT IN VERY GOOD AGREEMENT ON HOW FAR SOUTH THE COLD FRONT PUSHES AND HOW QUICKLY IT PUSHES BACK NORTH. NEVERTHELESS...THE MODELS DO INDICATE A CHANCE OF SHOWERS...PERHAPS THUNDERSTORMS...WILL MOVE BACK INTO THE REGION FROM THE WEST. THE ECMWF IS FASTER BRINGING THE THREAT OF SHOWERS AND THUNDERSTORMS BACK INTO THE REGION AS QUICKLY AS WEDNESDAY. JCL && .AVIATION... 18Z TAFS WIDESPREAD MVFR CIGS ACROSS THE MIDSOUTH THIS MORNING WILL GRADUALLY LIFT TO VFR THIS AFTERNOON. SCATTERED SHRA AND TSRAS EXPECTED ACROSS THE REGION AND WILL CONTINUE VCTS AT ALL TERMINALS THROUGH EARLY EVENING. COVERAGE WILL DIMINISH WILL LOSS OF HEATING THIS EVENING. QUIET OVERNIGHT THEN LOW CLOUDS SHOULD REDEVELOP LATER TONIGHT INTO EARLY SUNDAY...ESPECIALLY AT KJBR AND KTUP. A WEAKENING LINE OF SHRAS AND TSRAS WILL BE PUSHING INTO THE MIDSOUTH SUNDAY MORNING. SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER GUSTS THIS AFTERNOON AT MEM AND KJBR. SJM && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1257 PM CDT SAT MAY 16 2015 .UPDATE... 18Z TAF DISCUSSION. && .AVIATION... NUMEROUS -SHRA CONTINUE NEAR ALL AIRPORTS THIS AFTERNOON ALTHOUGH ACTIVITY IS BECOMING MORE SCATTERED WITH TIME. WILL HAVE -SHRA UNTIL 21-00Z AT TERMINALS WITH VCSH AFTERWARDS...BUT ADDITIONAL -SHRA AT CSV AFTER 03Z AS HRRR SHOWS ANOTHER ROUND MOVING THROUGH. WILL LEAVE OUT MENTION OF TS DUE TO LIMITED INSTABILITY IN THE VERY MOIST AIRMASS. IFR/MVFR CIGS/VIS WILL PREVAIL THROUGH 00Z WITH MVFR/VFR AFTER THAT TIME. LIGHT SOUTH WINDS ANTICIPATED THROUGH THE TAF PERIOD. SHAMBURGER && .PREV DISCUSSION... /ISSUED 927 AM CDT SAT MAY 16 2015/ UPDATE...MADE SOME MINOR ADJUSTMENTS TO POPS AND HOURLY TRENDS...OTHERWISE FORECAST ON TRACK. SHOWERS COVERED MUCH OF MID TN THIS MORNING...AND THIS WILL CONTINUE THROUGH MIDDAY. DURING THE AFTERNOON...THE COVERAGE OF SHOWERS WILL DECREASE SLIGHTLY FROM SOUTHWEST TO NORTHEAST...ALLOWING FOR SOME BREAKS IN THE RAINFALL. THIS WILL ALSO ALLOW A LITTLE MORE DESTABILIZATION...AND A BETTER CHANCE FOR ISOLATED THUNDERSTORMS. NO SEVERE WX IS EXPECTED. RAINFALL AMOUNTS TODAY WILL RANGE MOSTLY FROM ONE QUARTER TO THREE QUARTERS OF AN INCH. THE EXTENSIVE SHOWERS/CLOUDS WILL LIMIT HIGH TEMPS TO THE 70S FOR MOST AREAS. 13 PREV DISCUSSION... /ISSUED 627 AM CDT SAT MAY 16 2015/ UPDATE...FOR 12Z AVIATION. AVIATION...12Z TAF DISCUSSION. SHOWERS ARE MOVING NORTHWARD INTO MIDDLE TN AT ISSUANCE AND SHOULD BEGIN AFFECTING ALL 3 TERMINALS OVER THE NEXT COUPLE OF HOURS. FLIGHT CATEGORIES WILL WAVER BETWEEN VFR AND MVFR FOR THE MOST PART AS THESE LIGHT TO MODERATE RAIN MOVE THROUGH THE STATE. SOME TS MAY BE MIXED IN BUT JUST COVERED WITH VCTS ATTM. ACTIVITY WILL CONTINUE ON AND OFF THROUGHOUT THE DAY AND INTO THE EVENING HOURS. SOME IFR CIGS/VIS CAN BE EXPECTED WITH ANY HEAVIER RAINS AND/OR TS. SOUTHERLY WINDS WILL BE 8-12 KTS THROUGHOUT THE DAY WITH A GUST TO 20 OR 25 KTS POSSIBLE IN AND AROUND ANY TS THAT MAY AFFECT A TERMINAL. UNGER PREV DISCUSSION... /ISSUED 218 AM CDT SAT MAY 16 2015/ DISCUSSION...SURFACE MAP AT 06Z SHOWS AN INCREASING SOUTHERLY FLOW AS THE NEXT ACTIVE WEATHER SYSTEM DEEPENS OUT WEST. EARLIER SHOWERS HAVE ALL BUT DISSIPATED ACROSS MIDDLE TENNESSEE, WITH MINIMAL ACTIVITY EXPECTED OVERNIGHT. LOOK FOR MORE WIDESPREAD SHOWERS TODAY AS A WEAK UPPER TROUGH PROVIDES SOME FOCUSING FOR DEEPER MOISTURE, ALTHOUGH THE FORECAST MODEL SOUNDINGS SHOW ONLY WEAK INSTABILITY TODAY. THUS, THUNDERSTORMS WON`T BE WIDESPREAD; MOST OF TODAY`S ACTIVITY WILL BE SHOWERS ONLY. TOMORROW, WE CAN EXPECT A GREAT DEAL MORE INSTABILITY, BUT LESS MOISTURE CONTENT, SO POP`S ON SUNDAY WILL BE LOWER BUT THE CHANCE OF STORMS WILL BE GREATER. AT THIS TIME, WE ARE EXPECTING GENERAL THUNDERSTORMS ONLY, ALTHOUGH THE NEW DAY 2 CONVECTIVE OUTLOOK FROM THE SPC DOES BRING A MARGINAL RISK RIGHT UP TO OUR DOORSTEP, SO A FEW STORMS SUNDAY MAY AT LEAST BE STRONG. FROPA WILL LIKELY OCCUR MONDAY EVENING. AFTER A BRIEF SPELL OF HIGH PRESSURE, A FOLLOW-UP SYSTEM WILL MOVE THROUGH THURSDAY, BUT WITH MINIMAL EFFECTS. TEMPERATURES NEXT WEEK WILL BE SLIGHTLY COOLER THAN THIS WEEK`S, BUT NO SIGNIFICANT FLUCTUATIONS ARE EXPECTED THROUGH DAY 7. ROSE && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 55
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1049 AM CDT SAT MAY 16 2015 .UPDATE... AN AREA OF SHOWERS CONTINUE TO MOVE NORTH OVER PORTIONS OF WEST TENNESSEE...NORTHEAST ARKANSAS...AND THE MISSOURI BOOTHEEL. THIS AREA SHOULD MOVE INTO KENTUCKY AND MISSOURI BETWEEN 12-1 PM. MEANWHILE...DRY CONDITIONS ARE CURRENTLY OCCURRING OVER NORTH MISSISSIPPI. THE LATEST HRRR SHOWS ADDITIONAL DEVELOPMENT OCCURRING ACROSS SOUTHERN MISSISSIPPI THAT WILL MOVE INTO NORTH MISSISSIPPI AROUND 2 PM. THE CONVECTION WILL EVENTUALLY SPREAD INTO THE REST OF THE MIDSOUTH BETWEEN 3-5 PM. FORECAST LOOKS GOOD...NO UPDATES ARE EXPECTED. KRM && .DISCUSSION... /ISSUED 430 AM CDT SAT MAY 16 2015/ A WET DAY IS IN STORE FOR THE MIDSOUTH TODAY...FINALLY SEEMS MORE LIKE MAY ACROSS THE MIDSOUTH THAN WHAT WE HAVE EXPERIENCED THROUGH MUCH OF THE FIRST HALF OF THE MONTH. AREAS OF RAIN AND A FEW THUNDERSTORMS WERE ALREADY OCCURRING ACROSS THE MIDSOUTH EARLY THIS MORNING. THE WET PATTERN WILL CONTINUE INTO MONDAY AND WILL NEED TO MONITOR FOR THE POSSIBILITY OF FLOODING / FLASH FLOODING AS RAINFALL AMOUNTS INCREASE OVER TIME THROUGH THE WEEKEND INTO MONDAY. A LARGE UPPER LEVEL LOW WAS LOCATED OVER THE WESTERN UNITED STATES WITH AN UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST. A SOUTHERLY WIND FLOW BETWEEN THESE TWO SYSTEMS WAS PUSHING ABUNDANT MOISTURE INTO THE MIDSOUTH FROM THE GULF OF MEXICO. AN UPPER LEVEL SHORT WAVE WAS LOCATED OVER EAST TX AND WILL MOVE NORTHEASTWARD THROUGH THE MIDSOUTH TODAY. OCCASIONAL SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY. PRECIPITABLE WATER VALUES WILL BE BETWEEN 1.8 AND 2.0 INCHES WITH SURFACE DEW POINTS IN THE MIDDLE 60S TO NEAR 70 DEGREES. AS A RESULT...LOCALLY HEAVY RAINFALL MAY RESULT IN FLOODING IN SOME LOCATIONS TODAY...BUT NOT CONFIDENT ENOUGH THAT WILL BE WIDESPREAD ENOUGH FOR A FLASH FLOOD WATCH ATTM. DID MENTION THE THREAT OF LOCALLY HEAVY RAINFALL AND FLOODING IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. INSTABILITY LOOKS TO BE A LITTLE LESS THAN YESTERDAY WITH MORE WIDESPREAD RAIN AND CLOUDS. FOR TONIGHT...AN UPPER LEVEL TROUGH MOVES INTO THE CENTRAL PLAINS WITH AN ASSOCIATED COLD FRONT STRETCHING FROM KS INTO TX. ORGANIZED CONVECTION IS EXPECTED TO DEVELOP AHEAD OF THIS FRONT THROUGH THE PLAINS PERHAPS APPROACHING NORTHEAST ARKANSAS LATE TONIGHT...ALTHOUGH INSTABILITY DECREASING BY THAT TIME. WEAK UPPER LEVEL DISTURBANCES EMBEDDED IN SOUTHWEST FLOW ALOFT WILL CONTINUE THE THREAT FOR SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT ACROSS THE MIDSOUTH. SUNDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR WITH LOCALLY HEAVY RAINFALL A CONTINUING THREAT. THE UPPER LEVEL TROUGH WILL PUSH TO THE NORTHEAST THROUGH THE CENTRAL PLAINS WITH THE ASSOCIATED COLD FRONT REMAINING TO OUR WEST AND NORTH. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE TO OUR NORTH. 0-6 KM BULK SHEAR VALUES ARE ONLY MARGINAL FOR ORGANIZED SHEAR WEATHER NEAR EXTREME NORTHEAST ARKANSAS AND THE MO BOOTHEEL. HOWEVER... WIND FIELDS WILL BE STRONGER ACROSS THE MIDSOUTH SUNDAY AS THE UPPER LEVEL TROUGH MOVES TO OUR NORTH. THIS WILL ALLOW WARMER SURFACE TEMPERATURES TO PUSH INTO THE MIDSOUTH CAUSING GREATER INSTABILITY AND THE POSSIBILITY A FEW STRONG TO SEVERE THUNDERSTORMS. IF ANY SEVERE THUNDERSTORMS DO DEVELOP...DAMAGING WIND AND LARGE HAIL WOULD BE THE GREATEST SEVERE WEATHER THREATS. A COLD FRONT WILL SAG INTO THE MIDSOUTH FROM THE NORTH MONDAY AS THE UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST WEAKENS SOME WITH LOWERING UPPER LEVEL HEIGHTS ACROSS THE MIDSOUTH. WILL ONCE AGAIN NEED TO MONITOR FOR HEAVY RAINFALL AND FLOODING / FLASH FLOODING. THE COLD FRONT WILL GRADUALLY PUSH THROUGH THE MIDSOUTH MONDAY NIGHT AND TUESDAY WITH DECREASING CHANCES FOR RAIN FROM THE NORTH. TEMPERATURES WILL BE A LITTLE COOLER WITH PASSAGE OF THE COLD FRONT. FOR THE REMAINDER OF THE WORK WEEK...THE ECMWF AND GFS ARE NOT IN VERY GOOD AGREEMENT ON HOW FAR SOUTH THE COLD FRONT PUSHES AND HOW QUICKLY IT PUSHES BACK NORTH. NEVERTHELESS...THE MODELS DO INDICATE A CHANCE OF SHOWERS...PERHAPS THUNDERSTORMS...WILL MOVE BACK INTO THE REGION FROM THE WEST. THE ECMWF IS FASTER BRINGING THE THREAT OF SHOWERS AND THUNDERSTORMS BACK INTO THE REGION AS QUICKLY AS WEDNESDAY. JCL && .AVIATION... 12Z TAFS AN AREA OF SHOWERS WITH ISOLATED LIGHTNING STRIKES IS CURRENTLY BEING OBSERVED ACROSS MEM...JBR AND MKL. THIS WILL CONTINUE TO LIFT NORTH THIS MORNING WITH LOW CIGS ACCOMPANYING IT. CIGS DOWN TO MVFR AND OCCASIONALLY IFR AT TIMES ARE EXPECTED. EXPECT REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS DURING THE LATE MORNING HOURS ACROSS ALL TERMINALS SO VCTS COVERS THIS POTENTIAL UNTIL TIMING CAN BE NAILED DOWN. IT APPEARS THAT A LULL IN THE SHOWER ACTIVITY WILL OCCUR LATE SATURDAY NIGHT INTO SUNDAY MORNING ALTHOUGH WINDS WILL STAY ABOVE 10KTS THROUGH THE NIGHT FROM THE SOUTH. TVT && && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1133 PM CDT FRI MAY 15 2015 .UPDATE... 06 TAF DISCUSSION. && .AVIATION... LINE OF STORMS CROSSING TN RIVER WILL REACH CKV AROUND START OF TAF PERIOD. LEANED HEAVILY ON LATEST HRRR FOR TIMING...AND EXPECT -SHRA TO CONTINUE AT CKV THROUGH THE NIGHT...REACHING BNA BY 12Z AND CSV BY 14Z. MIX OF -SHRA/-TSRA EXPECTED BY 15Z AT ALL AIRPORTS AS INSTABILITY INCREASES WITH DAYTIME HEATING...WITH -SHRA/-TSRA CONTINUING TO 16/21Z. VFR CIGS TO BECOME MVFR BY 15Z AS PRECIP BECOMES MORE WIDESPREAD. LIGHT SOUTH WINDS ANTICIPATED THROUGH THE TAF PERIOD WITH OCCASIONAL GUSTS TO 20 KNOTS. SHAMBURGER && .PREV DISCUSSION... /ISSUED 635 PM CDT FRI MAY 15 2015/ UPDATE... IMPULSE TO RIDE NORTHEAST AND INFLUENCE THE WEATHER OVER THE MID STATE TONIGHT. BEST PVA TRAJECTORY APPEARS TO BE OVER WESTERN AREAS. FURTHERMORE...DEEPEST MOISTURE TO POOL OVER THAT REGION AS WELL. LATEST RADAR TRENDS SHOWS SOME INITIAL CONVECTION KNOCKING AT THE DOOR ALONG THE TN RIVER. WILL GO AHEAD AND UPDATE THE ZONES TO REMOVE THE LATE AFTERNOON WORDING. ALSO...WILL INCREASE POPS TO THE LIKELY LEVEL FAR WEST...WILL INCLUDE 50 POPS CENTRAL AREAS. OTW...HUMID AIRMASS SHOULD PREVENT TEMPS FROM DROPPING MUCH OVERNIGHT. MIN TEMPS SHOULD HOLD IN THE 60S SO NO CHANGES NEEDED. UPDATE OUT SHORTLY. PREV DISCUSSION... /ISSUED 623 PM CDT FRI MAY 15 2015/ AVIATION 00Z DISCUSSION... SHOWER AND TSTM ACTIVITY WILL MAKE A RUN AT THE AREA...MAINLY AFT 06Z. THE CATALYST WILL BE AN OVERNIGHT SHORTWAVE WHICH WILL BE RIDING NORTHWESTWARD THROUGH THE MID STATE. CIGS WILL LOWER OVERNIGHT AND VSBYS SHOULD GENERALLY REMAIN AT 3SM OR GREATER. CONVECTIVE COVERAGE WILL DECREASE AFT 18Z. PREV DISCUSSION... /ISSUED 238 PM CDT FRI MAY 15 2015/ DISCUSSION...AFTER MORE THAN 2 WEEKS WITHOUT SIGNIFICANT RAIN FOR MOST OF MID TN...SCATTERED THUNDERSTORMS HAVE DEVELOPED. THE POTENTIAL FOR WET WX WILL CONTINUE THROUGHOUT THE WEEKEND... ESPECIALLY ON SATURDAY. THIS IS GOOD NEWS TO MANY...BUT LOTS OF OUTDOOR EVENTS WILL BE IN JEOPARDY. FOR THE REMAINDER OF TODAY...SCATTERED SHOWERS AND STORMS WILL CONTINUE WITH POPS AROUND 40 PERCENT. NO SIGNIFICANT BOUNDARIES ARE EVIDENT TO INDICATE ANY SPECIFIC LOCATIONS THAT WILL BE IMPACTED. THE ACTIVITY WILL TEND TO DIMINISH AS THE SUN SETS THIS EVENING. OVERNIGHT...A FEW SHOWERS OR STORMS WILL LINGER...AND THE ACTIVITY MAY INCREASE AGAIN TOWARD DAYBREAK. A FEW AREAS OF FOG ARE POSSIBLE WITH LOWS IN THE MUGGY 60S. FOR SATURDAY...ALL SIGNS POINT TO LOTS OF SHOWERS AND THUNDERSTORMS. LOW LEVEL SOUTHERLY FLOW WILL CONTINUE TO BRING MOIST AIR FROM THE GULF WHILE SOUTHWEST FLOW ALOFT ADDS MOISTURE AND A COUPLE OF SHORTWAVE TROUGHS. PRECIPITABLE WATER VALUES WILL APPROACH 2 INCHES...ESPECIALLY OVER OUR NORTHWEST COUNTIES. THE GREATEST RAINFALL COVERAGE WILL BE SATURDAY MORNING THROUGH EARLY AFTERNOON WITH THE MAIN SHORTWAVE. AFTER THAT...THE COVERAGE WILL DECREASE...BUT THERE WILL CONTINUE TO BE PLENTY OF MOISTURE AND ADEQUATE INSTABILITY TO GENERATE CLUSTERS OF SHOWERS AND THUNDERSTORMS. RAINFALL AMOUNTS FOR SATURDAY WILL RANGE FROM ONE QUARTER TO ONE INCH...WITH THE HIGHER TOTALS EXPECTED GENERALLY OVER THE NORTHWEST HALF OF MID TN. BECAUSE OF THE RAIN AND CLOUDS...WE WILL GO ON THE LOW SIDE OF GUIDANCE TEMPERATURES FOR SATURDAY. THE COVERAGE OF SHOWERS AND STORMS WILL DECREASE SATURDAY NIGHT THROUGH SUNDAY...TO 40-50 PERCENT. CONDITIONS WILL REMAIN QUITE MUGGY WITH LOWS IN THE MID TO UPPER 60S. LOWER RAIN COVERAGE AND SOME INTERVALS OF SUNSHINE WILL BRING WARMER TEMPS ON SUNDAY...MAINLY LOW TO MID 80S. RAIN CHANCES WILL INCREASE AGAIN SUNDAY NIGHT INTO MONDAY AS A COLD FRONT APPROACHES. ANOTHER QUARTER TO 1 INCH OF RAINFALL IS EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. FORTUNATELY...WE DO NOT EXPECT ANY WIDESPREAD OR ORGANIZED SEVERE WX. COOLER AND DRIER AIR WILL FOLLOW THE FRONT FOR MIDWEEK. A COUPLE OF DISTURBANCES WILL BRING A SMALL CHANCE FOR SHOWERS BY THURSDAY THEN TRENDING WARM AND UNSETTLED AGAIN FOR NEXT WEEKEND. 13 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 55
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1028 AM CDT SAT MAY 16 2015 .UPDATE... A QUICK LOOK AT THE ENVIRONMENT THIS MORNING FROM THE 12Z FORT WORTH SOUNDING DOES SHOW SUBSIDENCE WAS RELATIVELY STRONGER THAN EXPECTED LATE YESTERDAY BEHIND THE DEPARTING SHORTWAVE. HOWEVER... LAPSE RATES ABOVE THE EML REMAIN STEEP AND MOISTURE RICH ENOUGH THAT SOME HIT AND MISS SHOWERS AND STORMS ARE POSSIBLE OVER THE REGION THIS AFTERNOON. TODAY. HIGH RES MODELS OUTSIDE OF THE RAPID REFRESH/HRRR HAVE DELAYED ACTIVITY INTO THE WESTERN COUNTIES UNTIL AFTER 00Z/7 PM. THE HRRR IS AN HOUR OR TWO SOONER FOR CONVECTIVE POTENTIAL. WE WILL BE ISSUING A SPECIAL 18Z SOUNDING EARLY THIS AFTERNOON TO RE-EVALUATE THE ENVIRONMENTAL CHANGES. WE HAVE TRIMMED BACK THE ARRIVAL FOR POSSIBLE DISCRETE SEVERE STORMS TO VERY LATE THIS AFTERNOON FOR MAINLY YOUNG/JACK/AND MONTAGUE COUNTIES WHERE AN ENHANCED RISK FOR SEVERE WEATHER REMAINS. THE MAIN UNCERTAINTY WILL BE THE DELAYED TIMING OF THE STRONGER MID-LEVEL HEIGHT FALLS/LARGE SCALE ASCENT AND THE MODEST EML CURRENTLY IN PLACE. THE DRYLINE REMAINS WELL TO THE WEST ACROSS EASTERN NEW MEXICO AND HAS A WAYS TO GO BEFORE REACHING OUR WESTERN COUNTIES LATE TODAY. REGARDLESS...BY THIS EVENING SEVERE STORMS WILL BE POSSIBLE ACROSS AREAS MAINLY NORTH OF I-20 AND WEST OF I-35/35W WITH ALL MODES OF SEVERE WEATHER POSSIBLE. HAVE MADE TIMING ADJUSTMENTS FOR THE DAYTIME PERIOD WITH ALL THESE ITEMS IN MIND. AS THE SYSTEM BECOMES LINEAR TO THE LARGE SCALE FORCING LATE THIS EVENING AND OVERNIGHT...IT WILL BE FED BY A STRENGTHENING LLJ AND ASSOCIATED WAA. THE SEVERE THREAT WILL BECOME MORE LOCALIZED WHILE THE HYDROLOGICAL THREAT RAMPS WITH POSSIBLE TRAINING STORMS WITH VERY HEAVY RAINFALL WITH PWAT VALUES WELL ABOVE NORMAL. CURRENT FLOOD PROBLEMS WILL ONLY BE EXACERBATED WITH FLASH FLOODING POSSIBLE DURING THE OVERNIGHT HOURS INTO SUNDAY MORNING. A FLASH FLOOD REMAINS IN EFFECT FOR MOST OF THE AREA THROUGH TONIGHT...THEN FOR OUR CENTRAL TEXAS COUNTIES ON SUNDAY. 05/ && .AVIATION... /ISSUED 656 AM CDT SAT MAY 16 2015/ MVFR CEILINGS WILL PREVAIL AT ALL TAF SITES THROUGH THE MORNING WITH CEILINGS LIFTING AND SCATTERING THIS AFTERNOON. VFR CONDITIONS ARE EXPECTED THIS EVENING EXCEPT IN AND NEAR THUNDERSTORMS. LIFT WILL BE ON THE INCREASE THROUGH THE AFTERNOON AS A POWERFUL UPPER LOW MOVES TOWARD THE NORTHERN HIGH PLAINS. WE EXPECT THUNDERSTORMS TO DEVELOP WEST OF THE TAF SITES LATE THIS AFTERNOON. THESE STORMS SHOULD ORGANIZE INTO A LINE AND MOVE EAST DURING THE EVENING. THE BEST WINDOW OF TIME FOR THE STORMS TO MOVE ACROSS THE METROPLEX TAF SITES WILL BE BETWEEN 05Z AND 09Z AND SLIGHTLY LATER IN WACO. A SOUTH WIND WILL PREVAIL THROUGH TONIGHT AT SPEEDS BETWEEN 11 AND 16 KNOTS WITH SOME HIGHER GUSTS DURING THE DAY. WINDS COULD BECOME STRONG AND GUSTY AS THE LINE OF THUNDERSTORMS MOVES THROUGH TONIGHT. 79 && .PREV DISCUSSION... /ISSUED 338 AM CDT SAT MAY 16 2015/ WV SAT LOOP SHOWS A BROAD UPPER LOW OVER THE INTERMOUNTAIN REGION WITH A SHORT WAVE TROUGH OVER SOUTHERN ARIZONA AND ANOTHER OVER WESTERN NEVADA. THE SOUTHERN RADAR MOSAIC THIS MORNING SHOWS SIGNIFICANT CONVECTION ALONG A DRYLINE/PACIFIC COLD FRONT OVER THE TEXAS HIGH PLAINS AND PANHANDLE REGION WHICH WILL CONTINUE TO ADVANCE TOWARD NORTH/CENTRAL TEXAS TODAY. AS THE CONVECTION ENTERS THE FAR WESTERN COUNTIES LATE THIS AFTERNOON...THERE COULD BE SOME MARGINALLY SEVERE TO SEVERE THUNDERSTORMS DUE TO HIGH CAPE AND 0-3KM SHEAR OF 35-40 KNOTS. ANY DISCRETE SUPERCELL WILL NEED TO BE WATCHED FOR STRONG ROTATING UPDRAFTS THAT COULD PRODUCE A TORNADO. COME THIS EVENING...THE STORMS SHOULD BECOME MORE LINEAR AND MORE PARALLEL TO THE UPPER FLOW WHICH WILL INCREASE THE POTENTIAL FOR ECHO TRAINING...HEAVY RAINFALL AND FLASH FLOODING DURING THE OVERNIGHT HOURS. THE HEAVY RAIN POTENTIAL WILL CONTINUE THROUGH SUNDAY MORNING OVER THE SOUTHEAST ONE HALF OF THE CWA...THUS WE HAVE DECIDED TO MOVE THE WATCH SOUTHEASTWARD AND EXTEND IT THROUGH SUNDAY AFTERNOON AS SOME AREAS MAY RECEIVE AN ADDITIONAL 1/2 TO 1 INCH DURING THE DAY. THE WATCH MAY NEED TO BE EXTENDED FURTHER INTO SUNDAY NIGHT IF THE QPF OF THE GFS AND ECMWF PANS OUT. WE WILL TACKLE PROBLEM ON THE NEXT COUPLE OF SHIFTS. SINCE THE AIR MASS DOES NOT CHANGE MUCH ON MONDAY...WE WILL CONTINUE TO CARRY A CHANCE OF CONVECTION DURING THE DAY WITH A LESSER CHANCE MONDAY NIGHT. A COLD FRONT WILL MOVE SOUTH OF THE RED RIVER LATE MONDAY NIGHT AND THEN STALL ALONG THE I-20 CORRIDOR ON TUESDAY. THE FRONT WILL MOVE BACK NORTH TUESDAY NIGHT ONLY TO COME BACK SOUTH LATER IN THE WEEK AS OUR NEXT UPPER SYSTEM MOVES THROUGH THE DESERT SOUTHWEST AND INTO THE CENTRAL ROCKIES. THE SHORT WAVE ENERGY ASSOCIATED WITH THIS SYSTEM SHOULD PASS FARTHER TO THE NORTHWEST OF NORTH TEXAS...THUS WE/LL KEEP POPS MOSTLY IN THE CHANCE CATEGORY TUESDAY THROUGH WEDNESDAY. HOWEVER...THERE IS A FAIRLY STRONG CONVECTIVE SIGNAL BEING ADVERTISED WEDNESDAY NIGHT PER THE GFS/ECMWF MODELS AND HAVE ADDED LIKELY POPS TO THE RED RIVER REGION FOR THE WEDNESDAY NIGHT PERIOD. THURSDAY THROUGH FRIDAY...WE/LL KEEP CHANCE POPS ACROSS THE CWA AS ANOTHER UPPER TROUGH DROPS DOWN THE WEST COAST AND INTO THE SOUTHWEST BY LATE NEXT WEEK. THIS WILL RESULT IN SLIGHT UPPER RIDGING ON THURSDAY FOLLOWED BY SOUTHWESTERLY FLOW ALOFT AND A COUPLE OF SHORTWAVE RIPPLES ON FRIDAY. THERE WILL BE LITTLE CHANGE IN MAX/MIN TEMPERATURES THROUGH THIS FORECAST...HIGHS MOSTLY 80-85 AND LOWS MOSTLY IN THE MID-UPPER 60S. 75 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 82 69 84 70 83 / 30 80 40 40 40 WACO, TX 83 71 83 70 83 / 30 70 70 50 50 PARIS, TX 81 69 82 69 81 / 40 80 60 50 40 DENTON, TX 80 68 84 68 84 / 30 80 30 40 30 MCKINNEY, TX 81 69 83 68 83 / 30 80 40 50 40 DALLAS, TX 82 69 85 70 84 / 30 80 50 50 40 TERRELL, TX 83 71 84 69 82 / 30 70 60 60 40 CORSICANA, TX 83 72 83 70 81 / 30 50 70 50 50 TEMPLE, TX 84 72 83 70 83 / 30 50 60 40 50 MINERAL WELLS, TX 81 66 84 67 84 / 40 80 30 20 30 && .FWD WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH SUNDAY MORNING FOR TXZ091>095-100>107-115>121-129>134-141. FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR TXZ147-148-158-160>162-174-175. FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH SUNDAY AFTERNOON FOR TXZ122-123-135-142>146-156-157-159. && $$ 79/05
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AREA FORECAST DISCUSSION
NWS PORTLAND
220 PM PDT SAT MAY 16 2015 .SYNOPSIS...A LARGE BUT WEAK UPPER LEVEL LOW PRES SYSTEM WILL REMAIN OVER THE REGION THROUGH MUCH OF THE COMING WEEK. A WEAK LOW LEVEL OFFSHORE FLOW SUN AND MON WILL LEAD TO WARMER TEMPS AS WELL AS A CHANCE FOR SHOWERS AND THUNDERSTORMS. ONSHORE FLOW WILL RETURN TUE FOR A LITTLE COOLING AGAIN BUT A CONTINUED CHANCE OF SHOWERS. THROUGH THE END OF THE WEEK TEMPERATURES WILL REMAIN CLOSE TO SEASONAL NORMALS WITH ENOUGH INSTABILITY FOR A FEW SHOWERS. && .SHORT TERM...RADAR AND SURFACE OBSERVATIONS HAVE SHOWN A FEW LIGHT SHOWERS OVER THE NORTHERN PART OF THE FORECAST AREA EARLY THIS AFTERNOON...THE RESULT OF SHALLOW INSTABILITY AND WEAK TROUGHINESS ALOFT. A NEW UPPER LOW SEEN IN WATER VAPOR PICTURES WELL OFFSHORE BETWEEN 135 AND 140W IS EXPECTED TO SLIDE SLOWLY SE INTO CA BY MON. THIS TURNS THE MID AND UPPER LEVEL FLOW MORE TO THE SE WITH TIME... WHILE WARMER TEMPS AT H8 WRAP IN FROM THE E. WITH REDUCED CLOUD COVER AND WARMER H8 TEMPS WILL SEE TEMPS WARM BACK TO A LITTLE ABOVE NORMAL FOR SUN AND MON. OVERALL THIS LEADS TO PROGRESSIVE DESTABILIZATION OF THE ATMOSPHERE...WITH NAM AND GFS MODEL SOUNDINGS INDICATING SOME INSTABILITY DEVELOPING OVER THE CASCADES BY SUN AFTERNOON. BETTER INSTABILITY IS DEPICTED MON WITH AN EL AS HIGH AS 35K FT. THE POTENTIAL INSTABILITY ALSO EXTENDS AS FAR W AS THE COAST RANGE MON. FORCING MECHANISM IS NOT QUITE AS OBVIOUS EITHER DAY AS THE MON SHORTWAVE DEPICTED PREVIOUSLY BY GFS AND ECMWF IS MUCH WEAKER. OVERALL WILL KEEP POPS CONSERVATIVE SUN MAINLY OVER THE CASCADES...THEN INDICATE BETTER CHANCES FOR MON WITH LIKELY POPS OVER THE CASCADES BASED ON GOOD INSTABILITY AND SOME DIFFLUNECE ALOFT. WILL ALSO CARRY THE SLIGHT CHANCE FOR THUNDER AS FAR W AS THE COAST RANGE BASED ON EASTERLY COMPONENT TO THE FLOW AND INSTABILITY. AS THE CA LOW MOVES WELL E TOWARDS UTAH TUE...LOW LEVEL FLOW TURNS BACK ONSHORE. THIS EXPECTED TO PUSH MARINE CLOUDS BACK INLAND FOR COOLER TEMPS. MODEL SOUNDINGS HOWEVER CONTINUE TO INDICATE MARGINAL INSTABILITY ALOFT WITH STILL SOME MID AND UPPER LEVEL MOISTURE. WILL NEED TO KEEP A CHANCE FOR SHOWERS IN THROUGH TUE. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...BROAD UPPER-LEVEL LOW REMAINS IN PLACE THROUGH THE WEEK...KEEPING COOLER CLOUDY MARINE AIRMASS IN PLACE OVER THE REGION THROUGH FRIDAY. THIS WILL KEEP THE AREA UNDER CLOUDY WEATHER WITH OCCASIONAL SHOWERS. MOISTURE STARTS TO WANE LATER IN THE WEEK...WHICH WILL LIMIT SHOWERS TO THE CASCADES. THE MODELS ARE SUGGESTING THAT AN UPPER LEVEL RIDGE TRIES TO PUSH THE UPPER-LEVEL LOW OFF TO THE EAST FOR SATURDAY WHICH COULD DRY WEATHER OUT FOR THE WEEKEND...BUT CONFIDENCE IS LOW ON TIMING AND WHETHER THIS WILL ACTUALLY OCCUR THIS FAR OUT IN THE FORECAST PERIOD. -MCCOY && .AVIATION...IFR CIGS WITH PERIODS OF IFR VSBYS WITH LIGHT DRIZZLE WILL CONTINUE AT THE COAST AT LEAST THROUGH 19Z AND PERHAPS INTO THE AFTERNOON THROUGH 21Z BEFORE IMPROVING TO MVFR. EXPECT A RETURN TO IFR CIGS LATE OVERNIGHT AROUND 10Z. INLAND...MODEL TIME HEIGHT MOISTURE SUPPORTS MARINE STRATUS CONTINUING OVERNIGHT WITH A FAVORING OF THE MORE PESSIMISTIC GFS. NAM12 APPEARS TO CLEAR THE SKIES TOO FAST AND ESPECIALLY GIVEN THE LONG FETCH OF UPSTREAM MOISTURE WHICH SHOULD CONTINUE TO REINFORCE THE MARINE LAYER. AS SUCH...EXPECT THE LARGELY VFR CIGS NOW TO LOWER THIS EVENING BACK TOWARD THE 025 AGL MARK WHERE THEY WILL PERSIST THROUGH 12Z AT LEAST AND LIKELY THROUGH 18Z BEFORE SHOWING SIGNS OF BREAKING UP. KPDX AND APPROACHES...VFR STRATUS CIGS AROUND 030-040 WILL LIKELY STAY IN PLACE THROUGH AT LEAST 12Z. CONFIDENCE HAS IMPROVED WITH A PERSISTENT VFR STRATUS TO STAY IN PLACE BUT LIKELY LOWER CLOSER TO THE 025 MARK AROUND 06Z. FIRST IMPRESSION HAS THE 025 STRATUS DECK REMAINING IN PLACE THROUGH THE MORNING PUSH WITH HINTS OF CLEARING AFTER 16Z AT THE EARLIEST. /JBONK && .MARINE...WEAK SURFACE HIGH PRESSURE OFFSHORE WILL COMBINE WITH SURFACE LOW PRESSURE INLAND TO PRODUCE MAINLY NORTHWEST TO NORTH WINDS FOR THE WEEK AHEAD. WIND GUSTS STAY BELOW 20 KTS FOR THE ENTIRE FORECAST. RELATIVELY MILD SWELL CONDITIONS FOR THE WEEK AHEAD. A COUPLE SMALLER SWELL TRAINS COMBINE FOR HEIGHTS OF 4 TO 5 FEET. LONGER PERIOD SWELLS AROUND 15 TO 17 SECONDS WILL SHORTEN INTO THE 11 TO 14 SECOND RANGE BY MID WEEK. EXPECT CHOP DURING THE EBBS BUT WITH A HEIGHT OF 5 FEET AND MAYBE 7 FEET ON THE VERY STRONG OVERNIGHT EBB...WILL NOT MEET CRITERIA AS WIND SPEEDS DO NOT SUPPORT CREATING MAIN CHANNEL BREAKERS. /JBONK && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...NONE. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
Area Forecast Discussion National Weather Service Spokane WA 1247 PM PDT SAT MAY 16 2015 .SYNOPSIS... Scattered showers with embedded thunderstorms will be possible for the next several days. The best chance of widespread showers and isolated thunderstorms will be late this afternoon and Sunday, especially over north Idaho and Northeast Washington. Seasonably mild conditions will continue through the next week with showers possible over the higher terrain. && .DISCUSSION... A minor update has been sent to extend the band of wrap around rain slightly to the west to include the Lewiston area. Radar trends as well as the HRRR suggest this area of rain will shift south and east of the Lewiston area and Camas Prairie by late morning so this is not expected to last much longer. For this afternoon the HRRR shows increasing shower and isolated thunderstorm development over NE Washington Mountains and Idaho Panhandle, and then drifting southwestward into the Spokane area, Okanogan Highlands, and Palouse by late this afternoon or early evening as a low level boundary helps initiate convection. Elevated dew points currently in the mid 40s to lower 50s around Spokane, Deer Park, and Sandpoint along with an eroding mid level cloud deck should allow for some morning and afternoon sun which will allow for increased surface heating to help inititate convection. It is this area that the 06z GFS has the best instability with uncapped CAPE values as high as 500-1000 J/KG. Brief heavy rain...small hail...and wind gusts to around 30 mph are the main threats with these storms. JW && .AVIATION... 18z TAFS: Main concern will the development of showers and isolated thunderstorms over NE Washington and North Idaho through early this evening. KGEG/KSFF/KCOE are most favored for this activity...although with only isolated coverage expected only went with VCTS in the TAF between 23z-02z based on HRRR timing which is currently lining up well with radar data. This activity should decrease after sunset although showers may increase in North Central WA overnight where the best mid level instability will lie ahead of a closed low near Vancouver Island. Mainly VFR conditions are expected through 18z Sun...although in heavier showers or storms a lowering of visibility is likely. Also overnight an increase in NE winds for KGEG/KSFF/KCOE should limit the fog/stratus potential. The NAM shows the best stratus potential overnight at KPUW...although confidence is low-moderate of this occurring as the GFS shows drying in the boundary layer late tonight/early Sunday as easterly flow begins to increase. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 72 51 69 49 72 49 / 40 60 10 10 10 10 Coeur d`Alene 68 48 69 45 72 47 / 70 60 10 10 10 10 Pullman 65 49 67 44 71 45 / 40 60 30 20 20 20 Lewiston 70 54 73 51 76 53 / 40 60 30 30 30 20 Colville 77 52 72 48 74 50 / 40 60 20 10 10 10 Sandpoint 69 48 69 40 70 41 / 70 50 10 10 10 10 Kellogg 65 46 68 43 70 44 / 70 60 10 10 10 10 Moses Lake 78 53 73 50 77 51 / 10 30 40 20 10 10 Wenatchee 78 55 72 54 78 55 / 10 50 50 20 10 10 Omak 79 52 72 50 76 49 / 10 50 50 20 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CDT SUN MAY 17 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 303 PM CDT SUN MAY 17 2015 MAIN CONCERN IS SEVERE THREAT LATE THIS AFTERNOON INTO THIS EVENING. LATEST WATER VAPOR SATELLITE IMAGERY SHOWS UPPER LEVEL LOW/TROUGH OVER EASTERN SOUTH DAKOTA AND WESTERN MINNESOTA...IN ADDITION A SHORTWAVE TROUGH OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. LATEST 19Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTHEAST NORTH DAKOTA AND WEST CENTRAL MINNESOTA...WITH A COLD FRONT EXTENDING SOUTH INTO WESTERN IOWA. LATEST SATELLITE IMAGERY SHOWS STRATUS OVER FORECAST AREA BECOMING MORE CELLUAR AND SCATTERED SHOWERS DEVELOPED OVER NORTH CENTRAL WISCONSIN AND PARTS OF SOUTHEAST MINNESOTA PER LATEST ARX RADAR. WITH THE STRATUS DECK OVER MUCH OF THE REGION THROUGH EARLY AFTERNOON HOURS...THIS HAS LIMITED INSTABILITY OVER FORECAST AREA THIS AFTERNOON...WITH THE 17.19Z LAPS SHOWING 200-800 J/KG OVER FORECAST AREA AND AROUND 1000-1200 J/KG ALONG AND JUST AHEAD OF THE COLD FRONT. THE LATEST SPC MESOSCALE ANALYSIS INDICATES 40 KNOTS OF 0-6KM SHEAR OVER FORECAST AREA...WITH THE BEST SHEAR IN THE 0-3KM SHEAR PER 17.18Z RAP OF 30 TO 40 KNOTS ALONG AND AHEAD OF SURFACE FRONT. SPC MESOSCALE 0-1KM SHEAR INDICATES ABOUT 10 TO 20 KNOTS ALONG AND AHEAD OF COLD FRONT. WITH MINIMAL INSTABILITY AND SHEAR DECREASING OVER FORECAST AREA...SEVERE THREAT OVER FORECAST AREA HAS DECREASED. HOWEVER CANNOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM WITH DAMAGING WINDS...LARGE HAIL OR POSSIBLY AN ISOLATED TORNADO LATE THIS AFTERNOON INTO THIS EVENING. MONDAY...FORECAST AREA REMAINS UNDER THE INFLUENCE OF THE UPPER LEVEL LOW/TROUGH OVER SOUTHERN ONTARIO AND LAKE SUPERIOR. THE 17.12Z GFS/NAM INDICATE COLD AIR ADVECTING INTO THE FORECAST AREA...WITH 925MB TEMPERATURES FALLING TO 0 TO MINUS 2 DEGREES CELSIUS OVER THE FORECAST AREA. HIGH TEMPERATURES ARE EXPECTED TO BE WELL BELOW NORMAL...WITH READINGS IN THE UPPER 40S TO LOWER 60S ACROSS THE FORECAST AREA. TIGHT PRESSURE GRADIENT WILL ALLOW FOR WINDS TO BE SUSTAINED AT 15 TO 20 KNOTS AND GUSTS OF 20 TO 30 KNOTS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 303 PM CDT SUN MAY 17 2015 TUESDAY INTO WEDNESDAY...SURFACE RIDGE BUILDS INTO MUCH OF MINNESOTA AND NORTHERN WISCONSIN. SUBSIDENCE UNDERNEATH THE RIDGE SHOULD ALLOW FOR DRY WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES TUESDAY AND TUESDAY NIGHT. PATCHY TO AREAS OF FROST IS POSSIBLE ACROSS PARTS OF CENTRAL WISCONSIN TUESDAY NIGHT INTO WEDNESDAY MORNING. MID TO HIGH CLOUDS STREAMING AHEAD OF SHORTWAVE TROUGH SOUTHWEST OF FORECAST AREA MAY NOT ALLOW TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE 30S. TIMING OF MOISTURE ABOVE 700MB WILL BE THE BIGGEST FACTOR AND THIS IS EVIDENT BY THE 17.12Z GFS/NAM. WEDNESDAY...SHORTWAVE TROUGH FLATTENS UPPER LEVEL SHORTWAVE RIDGE WEDNESDAY OVER NEBRASKA AND IOWA. WITH DRY AIRMASS IN PLACE OVER FORECAST AREA AND THE DEEPER FORCING/LIFT ASSOCIATED WITH SHORTWAVE TROUGH SOUTH OF FORECAST AREA...HIGHER PRECIPITATION/SHOWER CHANCES WILL REMAIN MAINLY SOUTH OF FORECAST AREA WEDNESDAY. HOWEVER...THE 17.12Z GFS/NAM SUGGEST 500-300MB PV ADVECTION ALONG THE MINNESOTA AND IOWA BORDER DURING THE DAY WEDNESDAY. WILL INTRODUCE A SMALL PRECIPITATION CHANCE OVER THE EXTREME SOUTH PART OF THE FORECAST AREA...AS THE 17.12 GFS/NAM DEVELOP LIGHT QPF...A HUNDREDTH OR TWO...OVER THE EXTREME SOUTHERN PART OF THE FORECAST AREA. MAIN FORECAST CONCERNS FROM WEDNESDAY NIGHT INTO MEMORIAL DAY WEEKEND ARE PRECIPITATION CHANCES FOR MEMORIAL DAY WEEKEND. THE 17.12Z GFS/ECMWF/GEM ARE IN GOOD AGREEMENT IN BUILDING IN SHORTWAVE/SURFACE RIDGE INTO THE UPPER MIDWEST AND GREAT LAKES REGION WEDNESDAY NIGHT INTO FRIDAY PROVIDING DRY WEATHER AND SLIGHTLY TO NEAR NORMAL TEMPERATURES BOTH DAYS. FOCUS TURNS TO MEMORIAL DAY WEEKEND...WHERE THE 17.12Z GFS/ECMWF ARE IN GOOD AGREEMENT IN EJECTING PIECES OF ENERGY OUT OF UPPER LEVEL LOW/TROUGH OVER THE SOUTHWEST UNITED STATES INTO THE CENTRAL UNITED STATES. BOTH THE 17.12Z GFS/ECMWF SHOW INCREASING LOW LEVEL JET/MOISTURE TRANSPORT/CONVERGENCE AND LIFT/FORCING SATURDAY INTO SUNDAY INTO THE FORECAST AREA. WILL CONTINUE TO TREND OF SHOWERS AND THUNDERSTORMS SATURDAY INTO SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1100 PM CDT SUN MAY 17 2015 LOW CLOUDS ADVANCING QUICKER EAST THAN ORIGINALLY ANTICIPATED...AND WILL BE ACROSS KRST/KLSE AROUND 06Z. ONCE IN...EXPECT THE MVFR CLOUDS TO HOLD INTO THE MORNING HOURS...WITH SOME DIURNAL BUMP UP INTO VFR BY MID/LATE MORNING MON. LIKELY SEE A RETURN TO MVFR CIGS MONDAY EVENING. STRONG WINDS AT KRST FOR THE FIRST PART OF THE OVERNIGHT...SUSTAINED 20 TO 25 WITH GUSTS UPWARDS OF 35 KTS. MODELS SUGGEST IMPROVEMENT BY 09Z OR SO...BUT WINDS SHOULD CONTINUE NEAR 20 KTS WITH HIGHER GUSTS INTO EARLY MON EVENING AT KRST. SLIGHTLY LESS AT KLSE. THERE WILL BE IMPROVEMENT LATER MONDAY NIGHT AS HIGH PRESSURE STARTS TO APPROACH FROM THE NORTHERN PLAINS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DTJ LONG TERM...DTJ AVIATION...RIECK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
834 PM CDT SUN MAY 17 2015 .UPDATE... LOOKS LIKE ANY CHANCE FOR SHOWERS HAS ENDED. THE DRY AIR HAS OVERSPREAD THE AREA AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WON/T HAVE ANYTHING TO WORK WITH AND WILL COME THROUGH DRY LATE TONIGHT THROUGH ABOUT MID MORNING ON MONDAY. SO...LOOK FOR A FAIRLY QUIET NIGHT WITH WINDS REMAINING SOMEWHAT ELEVATED AND TEMPS FALLING BACK INTO THE MID 50S TO LOWER 60S. && .AVIATION/06Z TAFS/... VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. THE ONLY OPERATIONAL CONCERN WILL BE LOW LEVEL WIND SHEAR THROUGH ABOUT 10-12Z MONDAY. WINDS AT 2000FT WILL BE AROUND 35-40KTS WHILE AT THE SURFACE THEY MAY DIMINISH TO AROUND 10KTS. A COLD FRONT WILL SWEEP ACROSS THE AREA...DRY...FROM ABOUT 10-14Z MONDAY WITH WINDS BECOMING WESTERLY BEHIND THE FRONT. WINDS WILL BE GUSTY TO NEAR 25 KNOTS MONDAY AFTERNOON...DIMINISHING BY MONDAY EVENING. && .PREV DISCUSSION... /ISSUED 330 PM CDT SUN MAY 17 2015/ SHORT TERM... TONIGHT...FORECAST CONFIDENCE MEDIUM. THE HRRR MODEL HAS BEEN CONSISTENT TODAY AND SO FAR CORRECT. OTHER MESO MODELS ARE SIMILAR. A LINE OF SHOWERS AND THUNDERSTORMS WAS ORIENTED ROUGHLY NORTH TO SOUTH ACROSS THE CENTRAL MKX FORECAST AREA AT 2 PM THIS AFTERNOON. THIS LINE IS SLOWLY TRACKING EAST WITH MID LEVEL VORTICITY ADVECTION. THESE ARE WORKING OFF THE HIGHER CAPE AXIS THAT DEVELOPED OVER INLAND WI AREAS AND ALSO WEAK SURFACE CONVERGENCE. THE CONVECTION IS LOW-TOPPED SINCE MID LEVEL LAPSE RATES ARE WEAK. THEREFORE... MANY OF THE ECHO TOPS ARE BENEATH THE FREEZING LEVEL OF 12.5 KFT AND ARE NOT EVEN PRODUCING THUNDER. SEVERAL CELLS HAVE TOPS AROUND 20 KFT AND WE ARE SEEING CLOUD TO GROUND LIGHTNING STRIKES WITH THEM. PER THE HRRR AND OTHER MESO MODELS... THESE SHOWERS WILL CONTINUE EAST THROUGH 6 PM... ALL THE WAY THROUGH MILWAUKEE. EXPECT HEAVY DOWNPOURS. BRIEF LOCALIZED FLOODING IS POSSIBLE IN URBAN AREAS. THERE IS A BREAK BEHIND THIS LINE OF SHOWERS AND STORMS LATE THIS AFTERNOON. LOOK FOR GUSTY SOUTH-SOUTHWEST WINDS AS THE LOW LEVELS MIX OUT AND DEWPOINTS DROP TO AROUND 60. CAPE/INSTABILITY WILL LOWER IN THIS AREA. 0-6KM BULK SHEAR WILL REMAIN HIGH... AROUND 40 KT. THERE IS ONE MORE CHANCE FOR STORMS ACROSS SOUTHERN WI THIS EVENING... BUT THE CHANCE IS BECOMING VERY LOW. THE HRRR... NAMNEST AND OTHER MESO MODELS ARE SHOWING QUITE A DRY SCENARIO FOR OUR AREA. THE FEATURE WE HAVE BEEN FOCUSING OUR ATTENTION ON FOR SEVERE POTENTIAL IS AN UPPER LEVEL WAVE AND A SURFACE PRE-FRONTAL TROUGH ASSOCIATED WITH AN OCCLUDING LOW PRESSURE SYSTEM OVER THE EASTERN DAKOTAS AND WEST CENTRAL MN. THE UPPER WAVE NOW LOOKS LIKE IT WILL COME THROUGH SOUTHERN WI A LITTLE AHEAD OF THE PRE-FRONTAL TROUGH... SO DEVELOPMENT OF STORMS WILL BE HARDER TO ACHIEVE. IF ANY STORMS DEVELOP... THE CAPE WILL BE MARGINAL AND SHEAR WILL BE HIGH. THUS... THERE IS STILL A SMALL RISK FOR SEVERE. SPC STILL HAS OUR AREA IN A SLIGHT RISK FOR SEVERE STORMS. SKIES SHOULD CLEAR LATE THIS EVENING WITH THE DRY AIR WRAPPING INTO SOUTHERN WI AS THE SURFACE LOW TRACKS INTO NORTHEAST MN. WINDS WILL SHIFT TO THE SW AND WEST TOWARD MORNING. MONDAY...FORECAST CONFIDENCE HIGH. THE SURFACE/925MB COLD FRONT WILL TRACK THROUGH SOUTHERN WI DURING THE DAY MONDAY. IT WILL BE SLOW TO REACH SOUTHEAST WI... THUS MAX TEMPS WILL BE IN THE MID 70S THERE. THE DELLS AREA WILL BE COOLEST WITH HIGHS AROUND 60. EXPECT BRISK AND GUSTY WEST WINDS DUE TO A STRONG PRESSURE GRADIENT OVER THE REGION. MONDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM. THE UPPER LOW OVER NRN MN WILL BECOME AN OPEN WAVE AND MOVE ACROSS LAKE SUPERIOR AND INTO ONTARIO CANADA MON NT. A WEAKER SHORTWAVE TROUGH WILL ALSO MOVE ACROSS CENTRAL WI DURING THAT TIME. THE SHORTWAVE WILL LIKELY AID IN BROKEN STRATUS SHIFTING SOUTH INTO S WI ALONG WITH THE NWLY SFC FLOW AND COLD ADVECTION. NLY SFC FLOW WILL CONTINUE INTO TUE BUT WITH WEAKENING COLD ADVECTION. DAYTIME HEATING AND DRIER AIR SHOULD BE ENOUGH TO SCATTER OUT THE STRATUS DECK. HOWEVER HIGH TEMPS WILL REMAIN WELL BELOW NORMAL WITH 925 MB TEMPS ONLY WARMING TO 5-7C. AN UPPER LOW OVER THE WRN USA WILL THEN OPEN UP AS A SHORTWAVE TROUGH AND MOVE TOWARD WI FOR WED. DESPITE MID LEVEL FRONTOGENESIS OVER THE REGION...KEPT THE FCST DRY AS MUCH OF THE LOW TO MID LEVEL WARM...MOIST ADVECTION STAYS TO THE SOUTH. THUS EXPECT MO CLOUDY SKIES FROM MIDDLE TO HIGH CLOUDS. THE CLOUDS WILL KEEP THE HIGH TEMPS MAINLY IN THE 50S FOR THE 2ND DAY IN A ROW. LONG TERM... THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM. THE SRN PERIPHERY OF AN UPPER TROUGH WILL MOVE ACROSS THE NORTHERN AND EASTERN GREAT LAKES THU-FRI. THIS IS EXPECTED TO BRING A WEAK AND DRY BACKDOOR COLD FRONT ACROSS SRN WI ON FRI. HIGH PRESSURE WILL THEN FOLLOW FROM THE NORTHERN GREAT LAKES TO THE EASTERN GREAT LAKES FOR FRI-SAT. FOR SAT NT AND SUN AN UPPER TROUGH WILL EJECT NEWD TOWARD WI FROM THE 4 CORNERS REGION ALONG WITH ITS SFC TROUGH. A GOOD SURGE OF WARM...MOIST ADVECTION AND SHOWERS/TSTORMS ARE EXPECTED. TEMPS WILL RETURN TO NEAR NORMAL FOR THE THU-SUN PERIOD. AVIATION/00Z TAFS/... AN AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL WI SHOULD EXPAND AS IT TRACKS INTO SOUTHEAST WI THROUGH 6 PM. THIS WILL BE ABOUT A 2 HOUR PERIOD OF MODERATE TO HEAVY RAIN AND OCCASIONAL THUNDER. LOOK FOR A QUIET PERIOD OF WEATHER LATE THIS AFTERNOON. THERE IS ONE MORE SMALL CHANCE FOR THUNDERSTORMS EARLY THIS EVENING... BUT THAT CHANCE IS NOW LOOKING VERY LOW. THE RISK FOR SEVERE WEATHER HAS DECREASED... BUT ISOLATED SEVERE STORMS ARE STILL POSSIBLE. LOOK FOR CLEARING SKIES OVERNIGHT. GUSTY WEST WINDS AND SCATTERED TO BROKEN VFR CUMULUS CLOUDS EXPECTED MONDAY. MARINE... DENSE FOG ADVISORY WAS EXTENDED UNTIL 00Z/ 7PM THIS EVENING DUE TO PERSISTENT SOUTHEAST WINDS AND WARM AND HUMID AIR OVER THE LAKE. INCREASING SOUTH TO SOUTHWEST WINDS SHOULD PUSH ANY LINGERING FOG OUT OF THE NEARSHORE WATERS THIS EVENING. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...DAVIS TONIGHT/MONDAY AND AVIATION/MARINE...MRC MONDAY NIGHT THROUGH SUNDAY...GEHRING
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
609 PM CDT SUN MAY 17 2015 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 608 PM CDT SUN MAY 17 2015 STORMS HAVE DIMINISHED IN INTENSITY AND COVERAGE THE LAST FEW HOURS OVER THE FORECAST AREA. MESO DATA SUGGESTS THE REGION OF POTENTIAL NEW DEVELOPMENT OF STORMS LIKELY OVER THE NORTHWEST HALF OF THE STATE...INCLUDING PARTS OF CENTRAL AND NORTH CENTRAL WISCONSIN WITH THE BEST SHEAR VALUES...AND STEEP SURFACE LAPSE RATES. ANTICIPATE THE SURFACE LAPSE RATES TO BE ON THE DECLINE THE NEXT FEW HOURS...SO THE THREAT OF STRONG TO SEVERE STORMS SHOULD LESSON. SPIRALING BANDS OF CONVECTION OVER EASTERN MINNESOTA AND FAR WESTERN WISCONSIN CLOSER TO THE LOW PRESSURE AREA OVER NORTHERN MINNESOTA MAY ROTATE INTO THIS ENVIRONMENT AND INTENSIFY OVER NORTH CENTRAL WISCONSIN THIS EVENING. && .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 229 PM CDT SUN MAY 17 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED LOW PRESSURE SYSTEM SPINNING OVER THE EASTERN DAKOTAS. SHORTWAVES ARE ROTATING NORTHWARD AHEAD OF THIS OCCLUDED CYCLONE...THE STRONGEST OF WHICH IS LOCATED OVER EASTERN IOWA. A PWAT AXIS IS MOVING ACROSS WISCONSIN EARLY THIS AFTERNOON...WHICH COMBINED WITH MOISTURE CONVERGENCE...IS CONTRIBUTING TO SCATTERED SHOWER DEVELOPMENT OVER CENTRAL WISCONSIN. CLOUD COVER HAS SIGNIFICANTLY SLOWED THE HEATING CURVE SO FAR TODAY...KEEPING ML CAPES BELOW 200 J/KG. WITH SHOWER COVERAGE EXPECT TO INCREASE THROUGH THE AFTERNOON...IT WILL BE TOUGH TO SEE MUCH OF AN INCREASE OF INSTABILITY. STILL THOUGH...RADAR ECHOES SUGGEST SOME THUNDERSTORMS WILL BE POSSIBLE...AND ANY STORMS COULD BRING DOWN STRONG WINDS FROM ALOFT. WILL HAVE TO KEEP A MENTION OF ISOLATED DAMAGING WINDS THROUGH EARLY THIS EVENING. OTHERWISE...THE LATEST HRRR CONGEALS THE SHOWER ACTIVITY INTO BAND AND PROGRESSES IT ACROSS THE FORECAST AREA FOR THE REST OF THE AFTERNOON. TONIGHT...LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN MINNESOTA...WHILE A COLD FRONT WILL PUSH EAST THROUGH ALL BUT FAR EASTERN WISCONSIN OVERNIGHT. THOUGH SHORTWAVE ENERGY WILL BE ROTATING NORTHEAST OVER NORTHWEST WISCONSIN THROUGH THE EVENING...CONCERNED THAT STRONG DRYING AND INCREASING CAPPING IN THE MID-LEVELS WILL EVEN FURTHER LIMIT THUNDERSTORM POTENTIAL FOR THE FIRST COUPLE HOURS IN THE EVENING. WILL KEEP A MENTION OF ISOLATED DAMAGING WINDS THROUGH 02Z IN CASE SOME THUNDERSTORMS MAKE A RUN INTO N-C WISCONSIN FROM MINNESOTA. ONCE THE THREAT OF STORMS ENDS...MODELS SHOW CLEARING TAKING PLACE UNTIL LOW CLOUDS FLOOD EAST BEHIND THE COLD FRONT LATE TONIGHT. LOW TEMPS NEAR 60 OVER THE EAST...BUT COOLING TO NEAR 50 OVER THE WEST. MONDAY...OCCLUDED LOW PRESSURE WILL BE WEAKENING AS IT MOVES TO THE EAST ACROSS LAKE SUPERIOR. WEST WINDS ON THE SOUTHERN FLANK OF THE LOW WILL BE COLD ADVECTING THROUGH THE DAY...WHILE PUSHING IN WRAP AROUND MOISTURE. SHOULD SEE AMPLE CLOUD COVER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THROUGH THE DAY...BUT EAST-CENTRAL WISCONSIN WILL LIKELY SEE SOME SUN IN THE MORNING BEFORE CLOUDS INCREASE IN THE AFTERNOON. WITH THE SUNSHINE...TEMPS SHOULD WARM TO NEAR 70 IN THE EAST...BUT ONLY INTO THE MID AND UPPER 50S OVER THE WEST. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 229 PM CDT SUN MAY 17 2015 MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK...DRY AND MILDER CONDITIONS FOR THE LATTER HALF...AND A POSSIBLE RETURN TO WET WEATHER LATER IN THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST CONCERNS. THE REMNANTS OF THE UPPER LOW WILL TRACK ACROSS NORTHERN LAKE SUPERIOR ON MONDAY NIGHT...FOLLOWED BY A S/W TROF PASSING NORTH OF WI ON TUESDAY. UNSEASONABLY COLD AIR (H8 TEMPS -8 TO -10 C) WILL FLOW INTO THE REGION ON NNW WINDS...SETTING THE STAGE FOR SOME LAKE-ENHANCED SHOWERS OVER NC WI. LOW-LEVEL TEMPS AND THICKNESSES SUPPORT A MIX THEN CHANGEOVER TO SNOW LATE MONDAY NIGHT INTO TUESDAY MORNING...WITH LITTLE OR NO ACCUMULATION EXPECTED. ANY LINGERING PCPN SHOULD END TUESDAY AFTERNOON AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION. HIGH PRESSURE WILL COVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. STILL EXPECTING FROST TUESDAY NIGHT...BUT GETTING A LITTLE CONCERNED ABOUT THE POSSIBILITY OF THICKER HIGH LEVEL CLOUDS...DUE TO THE PRESENCE OF A STRONG JET STREAK OVER THE REGION. RIGHT NOW...HAVE JUST BUMPED UP CLOUD COVER A BIT OVER C/EC WI...BUT KEPT MOSTLY CLEAR SKIES OVER NORTHERN WI. WILL CONTINUE TO CARRY WIDESPREAD FROST OR FREEZE CONDITIONS OVER NORTHERN WI...AND PATCHY FROST OVER MOST OF C/EC WI. A WEAK BACK DOOR COLD FRONT WILL SAG THROUGH THE FORECAST AREA THURSDAY INTO THURSDAY NIGHT...BUT WILL NOT HAVE ANY MOISTURE TO WORK WITH...SO DRY WEATHER WILL PREVAIL. BEHIND THE FRONT...CANADIAN HIGH PRESSURE WILL REESTABLISH ITSELF OVER THE WESTERN GREAT LAKES...AND IS EXPECTED TO LINGER INTO SATURDAY. ABUNDANT SUNSHINE SHOULD BRING A RETURN TO NEAR NORMAL TEMPERATURES FOR THE LATTER HALF OF THE WEEK. AN UPPER TROF...LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL IMPACT THE REGION FROM SATURDAY NIGHT INTO SUNDAY. GULF MOISTURE IS EXPECTED TO FLOW INTO THE REGION AHEAD OF THE FRONT...WITH PRECIPITABLE WATER VALUES REACHING 1.00-1.25 INCHES. HAVE RAMPED POPS UP TO LIKELY FOR SUNDAY. THE ECMWF PULLS MOST OF THE PCPN OUT OF THE REGION SUNDAY EVG...WHILE THE GFS HANGS ONTO SIGNIFICANT QPF INTO MEMORIAL DAY...SO FCST CONFIDENCE WANES BEYOND SUNDAY. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 552 PM CDT SUN MAY 17 2015 MARGINAL TO STRONG SHEAR ALONG WITH MARGINAL INSTABILITY WILL CONTINUE TO PRODUCE AN ENVIRONMENT FOR THE DEVELOPMENT OF STORMS THIS SUNDAY EVENING. PRIMARY FOCUS OF STRONGER STORMS THIS EVENING APPEAR TO BE OVER THE NORTHWEST HALF THE STATE INCLUDING PARTS OF CENTRAL AND NORTH CENTRAL WISCONSIN. IFR CONDITIONS WITH LIFR CIGS WILL LINGER ALONG THE LAKE MICHIGAN SHORE LINE. SOUTHWEST WINDS WILL IMPROVE CONDITIONS OVERNIGHT. OTHERWISE AFTER A PERIOD OF VFR CONDITIONS OVERNIGHT...MVFR CIGS WILL FILTER INTO THE STATE FROM NORTHWEST TO SOUTHEAST THROUGH MONDAY WITH BLUSTERY WEST TO NORTHWEST WINDS. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........TDH SHORT TERM.....MPC LONG TERM......KIECKBUSCH AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
337 PM CDT SAT MAY 16 2015 .SHORT TERM... TONIGHT THROUGH SUNDAY AFTERNOON...FORECAST CONFIDENCE MEDIUM. WIDELY SCATTERED THUNDERSTORMS PERSIST THROUGH LATE AFTERNOON. THESE ARE BEING TRIGGERED BY A WEAK MID LEVEL SHORTWAVE APPROACHING FROM IA/IL. MODEL SOUNDINGS AND RAP SPC MESOSCALE ANALYSIS ARE SHOWING TALL SKINNY CAPE VALUES OF 1000 TO 2000 J/KG INLAND FROM THE LAKESHORE THIS AFTERNOON. THERE IS NOT MUCH SHEAR... SO ONLY BRIEF SMALL HAIL WOULD BE POSSIBLE IN ANY STRONGER STORMS. THE MAIN THREAT WILL BE BRIEF HEAVY RAIN SINCE PRECIPITABLE WATER VALUES ARE AROUND 1.3 INCHES TODAY. THESE THUNDERSTORMS WILL DIMINISH AFTER SUNSET THIS EVENING. LIGHT WINDS AND SMALL DEWPOINT DEPRESSIONS WILL LEAD TO PATCHY FOG AND LOW CLOUDS ACROSS SOUTHERN WI OVERNIGHT. THERE IS A CHANCE THAT MARINE FOG WILL SPREAD INLAND ONCE AGAIN. THE CLOUDS WILL LIKELY LINGER INTO THE MID SUNDAY MORNING HOURS. SURFACE LOW PRESSURE OVER THE DAKOTAS WILL TRACK INTO MINNESOTA TONIGHT AND STALL THROUGH SUNDAY AS IT OCCLUDES. THE 850 MB WARM CONVEYOR BELT... OR WARM MOIST AIR TRANSPORT... WILL LIFT THROUGH SOUTHERN WI SUNDAY MORNING INTO THE EARLY AFTERNOON. THIS WILL BRING A BAND OF NUMEROUS SHOWERS AND THUNDERSTORMS THAT SHOULD MARCH NORTHEAST ACROSS SOUTH CENTRAL AND SOUTHEAST WI. THERE IS SOME CONCERN THAT AN EMBEDDED THUNDERSTORM COULD BECOME SEVERE DURING THE AFTERNOON AS THE ATMOSPHERE BECOMES LESS STABLE. MODELS ARE HINTING AT SOUTHEAST WI AND LAKE MICHIGAN HAVING THE GREATEST THREAT FOR ENHANCED THUNDERSTORMS ON THE BACK EDGE OF THIS FIRST ROUND. TEMPERATURES WILL RISE INTO THE UPPER 70S... SIMILAR TO TODAY. LAKESHORE TEMPS WILL BE A LITTLE COOLER THAN INLAND GIVEN A SLIGHT EASTERLY COMPONENT. WINDS WILL BE STRONG OUT OF THE SOUTH DUE TO A TIGHT PRESSURE GRADIENT WITH THE APPROACHING SURFACE LOW. LATE SUNDAY AFTERNOON THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM. THE OCCLUDED LOW OVER NW MN WILL WEAKEN TO A BROAD W-E SFC TROUGH STARTING LATE SUNDAY NIGHT AND THROUGH MONDAY AS IT MOVES ACROSS LAKE SUPERIOR AND INTO CANADA. BEFORE IT WEAKENS...THE PASSAGE OF A TRAILING UPPER TROUGH AXIS AND A PREFRONTAL SFC TROUGH WILL LIKELY INITIATE A NEW ROUND OF SCATTERED CONVECTION LATE SUNDAY AFTERNOON AND THROUGH THE EVENING. THE NAM AND SOME MESOMODELS ARE SHOWING WHAT WILL LIKELY BE DISCRETE SUPERCELLS DEVELOPING FROM THE MS RIVER EWD. A 60-65 KT 500 MB JET STREAK WILL ACCOMPANY THE UPPER WAVE...SUPPORTING 0-6 KM BULK SHEAR OF 50 KTS AND A SUPERCELL POTENTIAL WITH MLCAPE VALUES UP TO 1500 J/KG OVER SOUTH CENTRAL WI. A TORNADO RISK WILL BE PRESENT DUE TO 0-1 KM SRH OF 150-200 M2/S2 AND 0-1 KM BULK SHEAR RISING TO 25 KTS. LCL HEIGHTS WILL ALSO BE AT OR BELOW 1 KM WITH THE LFC ONLY SLIGHTLY HIGHER. SPC HAS UPGRADED TO AN ENHANCED RISK OF SEVERE TSTORMS OVER MUCH OF WESTERN AND CENTRAL WI...MENTIONING THE POSSIBILITY OF STRONG TORNADOES. CAPE VALUES WILL REMAIN BELOW 1000 J/KG OVER ERN WI AND THE STORMS MAY NOT ARRIVE UNTIL THE MIDDLE TO LATE EVENING...THUS THE SLIGHT RISK THERE. HOWEVER SHEAR VALUES DO BECOME STRONG AS WELL. THE ACTUAL COLD FRONT WILL GRADUAL MOVE ACROSS SRN WI ON MONDAY...THUS 70 DEGREE HIGHS ARE EXPECTED. NWLY FLOW AND COLD ADVECTION WILL THEN PREVAIL FOR MONDAY NIGHT AND TUESDAY. SRN WI APPEARS TO BE FAR ENOUGH SOUTH TO AVOID THE BROKEN STRATUS ON MONDAY BUT SOME STRATUS WILL BE POSSIBLE MONDAY NIGHT INTO TUESDAY. A CANADIAN AIRMASS AND LINGERING CLOUDS INTO TUE AFTERNOON WILL KEEP HIGH TEMPS ONLY IN THE 50S. .LONG TERM... TUESDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM. A LARGE SFC HIGH WILL EXTEND FROM THE GREAT PLAINS TOWARD THE OHIO RIVER VALLEY FOR THIS PERIOD. A RELATIVELY WEAK WNWLY FLOW ALOFT WILL PREVAIL WITH BELOW NORMAL TEMPS EXPECTED IN THE BEGINNING OF THE PERIOD BUT QUICKLY REBOUND TO SEASONAL NORMALS. NO PCPN IS EXPECTED. && .AVIATION/00Z TAFS/...COMING SOON. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...DENSE FOG ADVISORY UNTIL 10 AM CDT SUNDAY FOR LMZ643>646. && $$ TONIGHT/SUNDAY AND AVIATION/MARINE...MRC SUNDAY NIGHT THROUGH SATURDAY...GEHRING
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1129 PM MDT SUN MAY 17 2015 .SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT) ISSUED AT 331 PM MDT SUN MAY 17 2015 IN SPITE OF BUILDING HIGH PRESSURE OVER UTAH AND WARMING TEMPS ALOFT...AFTERNOON CAPE VALUES OF 250-500 J/KG SUGGEST CONVECTIVE SHOWERS WITH SOME THUNDERSTORMS. MOISTURE TRANSPORT DOES EXIST FROM THE UINTA MOUNTAINS TOWARD VAIL AND INDEPENDENCE PASS REGION...AND SHOWERS/STORMS WILL BE CONCENTRATED ACROSS THIS AREA. CONVECTIVE POTENTIAL EXIST ELSEWHERE BUT NOT AS NUMEROUS OVER SW COLORADO...AND MOSTLY DRY OVER SE UTAH. CONVECTIVE POTENTIAL MOSTLY DIMINISHES WITH SUNSET. NOT SO SURE THIS WILL BE THE CASE ACROSS PARTS OF ERN UTAH AS MOISTURE TRANSPORT INCREASES OVERNIGHT...THE HRRR SHOW CONVECTIVE SHOWERS PERSISTING PAST MIDNIGHT AND TRACKING OVER THE UINTA BASIN/MOUNTAINS. BY DAYBREAK...HIGH CLOUDS WILL BE SPREADING FROM THE SOUTH AS THE NEXT CALIFORNIA UPPER LOW ADVECTS MOISTURE TOWARDS THE FOUR CORNERS REGION. THE PACIFIC WAVE TRAIN CONTINUES MONDAY AS THE NEXT STORM SYSTEM MOVES SLOWLY ONSHORE...ITS CENTER SETTLING OVER CALIFORNIA/S SAN JOAQUIN VALLEY LATE IN THE AFTERNOON. SOUTHERLY FLOW AHEAD OF THE TROUGH WILL CAUSE MOISTURE LEVELS TO RISE ONCE AGAIN AS GULF MOISTURE IS TAPPED. GFS AND NAM BOTH INDICATED PRECIPITABLE WATER VALUES RISING TO NEAR 0.6 OF AN INCH. MEANWHILE...AN 110 KT JET ROTATES THROUGH THE BASE OF THE TROUGH GIVING IT A SLIGHTLY NEGATIVE TILT. THE NOSE OF THE JET PUSHES TOWARD THE FOUR CORNERS WHICH WILL PROVIDE CONSIDERABLE DIVERGENCE TO ADD TO THE DIFFLUENT FLOW ALOFT. THE DYNAMIC LIFT JUST DESCRIBED COMBINED WITH DAYTIME HEATING WILL GENERATE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FAVORING THE MOUNTAINS. AS MENTIONED IN THE PREVIOUS DISCUSSION...ARRIVING MOISTURE WILL BE HIGH BASED ACCORDING TO AREA TIME SECTIONS SO EXPECT MAIN STORM THREAT...ASIDE FROM LIGHTNING...WILL BE STRONG AND GUSTY OUTFLOW WINDS. WAA ADVECTION WILL CAUSE TEMPERATURES TO CLIMB CLOSER TO SEASONAL NORMS... THOUGH EXPECT CLOUDS AND SHOWERS WILL LIMIT HIGHS. THEREFORE... NUDGED MONDAY/S HIGHS TOWARD COOLER MAV GUIDANCE. MONDAY NIGHT WILL REMAIN ACTIVE AS THE PACIFIC SYSTEM MOVES OVER SOUTHERN NEVADA DURING THE NIGHT. DIFFLUENT/DIVERGENT FORCING REMAINS IN PLACE WHILE MOISTURE CONTINUES TO STREAM INTO THE AREA FROM THE SOUTH. AS A RESULT...WILL CONTINUE WITH LIKELY POPS IN THE MOUNTAINS WITH CHANCE POPS ACROSS THE VALLEYS. COLDER AIR BEGINS TO ADVECT OVER THE REGION DURING THE NIGHT CAUSING SNOW LEVELS TO LOWER TO AROUND 9000 TO 9500 FEET. EXPECT ACCUMULATING SNOW FOR AREAS ABOVE 10000 FEET WITH AMOUNTS OF UP TO 8 INCHES POSSIBLE ABOVE THE TIMBERLINE. MODELS SUGGEST AMOUNTS OF 12 INCHES OR MORE BUT APPEARS CONVECTIVE PARAMETERIZATION MAY BE A BIT OVERDONE AS LAPSE RATES ONLY MODERATELY UNSTABLE. IMPACTS TO ROADWAYS OVER THE HIGH PASSES PROBABLY NEGLIGIBLE WITH MOST SNOW MELTING ON CONTACT SO WILL HOLD OFF ISSUING HILITES. CLOUDS... SHOWERS AND WAA WILL YIELD MILDER OVERNIGHT LOWS AS PREVIOUSLY FORECAST. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 331 PM MDT SUN MAY 17 2015 COOL AND UNSETTLED CONDITIONS WILL CONTINUE TUESDAY AS THE PACIFIC STORM MOVES OVER THE REGION. SNOW LEVELS WILL RISE WITH DAYTIME WARMING...ESPECIALLY SOUTH...WHICH WILL INHIBIT ANY ADDITIONAL ACCUMULATIONS BELOW 10000 FEET. CONDITIONS IMPROVE TUESDAY NIGHT AS A TRANSIENT SHORTWAVE RIDGE BUILDS OVER THE AREA. ANOTHER LOW DEVELOPS OVER THE EASTERN PACIFIC AT MIDWEEK BUT STAYS QUASI-STATIONARY UNTIL THURSDAY NIGHT. A DRIER SOUTHWEST FLOW WILL MOVE OVER THE FORECAST AREA AHEAD OF THIS SYSTEM LIMITING MOIST CONVECTION TO THE MOUNTAIN AREAS DURING THE AFTERNOON AND EVENING WEDNESDAY AND THURSDAY. TEMPERATURES WILL RECOVER DURING THIS PERIOD REACHING NEAR NORMAL LEVELS THURSDAY AFTERNOON. THE PACIFIC SYSTEM THEN FOLLOWS THE WELL BEATEN PATH PREVIOUS STORMS HAVE TAKEN OVER THE PAST COUPLE OF WEEKS...TRACKING OVER EASTERN UTAH AND WESTERN COLORADO FRIDAY AND SATURDAY. CONSEQUENTLY...LOOK FOR AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY ONCE AGAIN ALONG WITH COOLER THAN NORMAL TEMPERATURES. CONDITIONS ON SUNDAY LESS CERTAIN AS LATEST ECMWF DRIVES A SHORTWAVE TROUGH ACROSS THE REGION FROM THE NORTHWEST WHILE GFS FAVORS A TRANSITORY RIDGE. BOTH SOLUTIONS POINT TO A CONTINUATION OF UNSETTLED CONDITIONS AS MOISTURE WILL LINGER IN EITHER CASE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1123 PM MDT SUN MAY 17 2015 A FEW SHOWERS WILL CONTINUE FOR THE NEXT SEVERAL HOURS ACROSS THE NORTH BEFORE DIMINISHING OVERNIGHT. VFR CONDITIONS WILL CONTINUE THROUGH THE MORNING HOURS ON MONDAY. SHOWERS AND THUNDERSTORMS WILL INCREASE LATE MONDAY AFTERNOON AND INCREASE IN COVERAGE BY MONDAY EVENING. HAVE INCREASED POPS AT TAF SITES WITH TEMPO/SHOWERS WORDING WITH CATEGORICAL PRECIPITATION OVER MOUNTAIN TAF SITES AT ASE AND TEX DEVELOPING BY 19/02Z. EXPECT VISIBILITY AND CEILINGS TO LOWER IN THE SHOWERS AND THUNDERSTORMS WITH MOUNTAIN BECOMING OBSCURED. SNOW LEVELS ARE EXPECTED TO BE AROUND 10000 FEET BUT LOWERING TO 9000 FEET IN HEAVIER SHOWERS. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...PF/NL LONG TERM...NL AVIATION...MPM
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1145 PM CDT SUN MAY 17 2015 .UPDATE... ISSUED AT 852 PM CDT SUN MAY 17 2015 OVERNIGHT FORECAST DOING WELL. SOUTHERLY WINDS MAINTAINING SOME WARM TEMPS FOR THE OVERNIGHT...AND MAJORITY OF PRECIP THREAT ALONG AND SOUTH OF A LINE FROM TAYLORVILLE TO CHAMPAIGN. SHORT TERM MODELS PREV BLEW SOME CONVECTION INTO SOUTHEASTERN IL WORKING OFF OF OUTFLOW FROM ACTIVITY IN MO. HOWEVER, ATMOSPHERE HAVING DIFFICULT TIME FOCUSING ANY LIFT, PARTICULARLY WITH THE LOSS OF THE DIURNAL COMPONENT TO THE INSTABILITY. SHOWERS SO FAR HAVE REMAINED LIMITED AND THE BULK OF THE THUNDER FURTHER TO THE SOUTH. ISO TS POSSIBLE IN THE FAR SE...BUT NOT WIDESPREAD. NOT MUCH IN THE WAY OF UPDATES ANTICIPATED AT THIS TIME. && .SHORT TERM...(TONIGHT) ISSUED AT 256 PM CDT SUN MAY 17 2015 POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF 2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT. HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57. .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 256 PM CDT SUN MAY 17 2015 COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY. WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE OVERNIGHT LOWS DIP INTO THE 40S. PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER. ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY AND FRIDAY. MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1136 PM CDT SUN MAY 17 2015 SOME MINOR ADJUSTMENTS TO INCLUDE A SCT LAYER AT 120-150 THIS EVENING WITH AUGMENTED SITES PICKING UP ON THE MID LEVEL MOISTURE STREAMING IN. SOME PRECIP WELL TO THE WEST KICKING UP ON OUTFLOW BOUNDARY FROM EARLIER STORMS IN SOUTH CENTRAL IOWA. MODELS NOT PICKING UP ON IT AT THIS POINT BUT SEE NO REASON TO INCLUDE IT AT THIS EARLY STAGE...WILL WATCH PIA FOR POTENTIAL IF IT HOLDS TOGETHER. FRONT MOVING THROUGH WILL BRING THE WINDS AROUND TO MORE WESTERLY MID MORNING FOR PIA... MORE MID DAY FOR REMAINING TAF SITES. MOSTLY A CIRRUS KIND OF DAY, THOUGH FORECAST SOUNDINGS AND CU RULE POINT TO A CU FIELD ROUGHLY ALONG AND SOUTHEAST OF A LINE FROM SPI TO BMI...DENSER TO THE SOUTH AND EAST AHEAD OF THE BOUNDARY. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...BARNES LONG TERM...BARNES AVIATION...HJS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
400 AM EDT MON MAY 18 2015 .SYNOPSIS... ISSUED AT 358 AM EDT MON MAY 18 2015 A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE UPPER 70S TO LOWER 80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO LOWER 50S. HIGH TEMPERATURES ON TUESDAY AND WEDNESDAY WILL RANGE FROM THE MID 50S TO LOWER 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 358 AM EDT MON MAY 18 2015 DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500 J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY IN ASSOCIATION WITH SOUTHERN STREAM. ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION. EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION LATER THIS AFTERNOON/THIS EVENING. SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR WILL BE POST-FRONTAL. SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL EXPERIENCE CLEARING SKIES IN THE EVENING. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 358 AM EDT MON MAY 18 2015 TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD. SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID 30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE FORECAST AT THIS POINT AND CONTINUE TO MONITOR. ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 122 AM EDT MON MAY 18 2015 MID LEVEL DRY SLOT HAS OVERSPREAD THE AREA WITH THE CHANCES OF CONVECTION OVERNIGHT HAVING DIMINISHED SIGNIFICANTLY. ANOTHER WEAK SHORT WAVE KICKING OUT OF SOUTHERN INDIANA MAY ALLOW FOR SOME SCATTERED SHOWERS TO LIFT BACK INTO NORTHEAST INDIANA THROUGH EARLY MONDAY MORNING...BUT BETTER CHANCES APPEAR TO BE SOUTHEAST OF FWA. MVFR CIGS OF 2-3K FT ARE POSSIBLE AT KFWA THROUGH AROUND 12Z...WITH GENERALLY VFR CONDITIONS OTHERWISE. A COLD FRONT TRACKING ACROSS THE AREA MONDAY AFTERNOON MAY ALLOW FOR ISOLD-SCT CONVECTION TO DEVELOP BUT INSTABILITY OF ANY CONSEQUENCE SHOULD BE LIMITED TO A FAIRLY NARROW ZONE ALONG AND IMMEDIATELY AHEAD OF THE FRONT. WITH OVERALL MID/UPPER FORCING ON THE WEAK SIDE...HAVE MAINTAINED VCTS MENTION AT KFWA DUE TO LOW CONFIDENCE OF THUNDER OCCURRENCE AT TERMINALS. SOUTHWEST WINDS IN ADVANCE OF THE FRONT SHOULD BECOME SOMEWHAT GUSTY INTO THE 18-23 KNOT RANGE THIS AFTERNOON...WITH WINDS SHIFTING TO THE WEST BEHIND THE FRONT LATE MONDAY AFTERNOON AT KSBN...AND EARLY MONDAY EVENING AT KFWA. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...AGD AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS JACKSON KY
434 AM EDT MON MAY 18 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON MAY 18 2015 03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY. THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND 17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE THIS AFTERNOON. ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 434 AM EDT MON MAY 18 2015 SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS. HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT. ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND. LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL BE TO OUR WEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 135 AM EDT MON MAY 18 2015 TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY. WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP TOMORROW AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...HAL AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
350 AM EDT MON MAY 18 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON MAY 18 2015 03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY. THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND 17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE THIS AFTERNOON. ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 350 AM EDT MON MAY 18 2015 LONG TERM DISCUSSION WILL BE ISSUES SHORTLY... && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 135 AM EDT MON MAY 18 2015 TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY. WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP TOMORROW AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...HAL AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
145 AM EDT MON MAY 18 2015 .UPDATE... ISSUED AT 145 AM EDT MON MAY 18 2015 AREA OF SHOWERS MOVING SLOWLY EAST ALONG THE TN/KY BORDER CONTINUE TO DIMINISH AT THIS LATE NIGHT HOUR. THIS WEAKENING TREND IS EXPECTED TO CONTINUE AND DID UPDATE POP GRIDS TO REFLECT THIS THOUGHT. THERE IS STILL SOME QUESTION AS TO HOW MUCH FOG WE WILL SEE WITH SOME AREAS ABLE TO CLEAR OUT...WHILE OTHERS MAY SEE LITTLE CLEARING. RIGHT NOW THINK THE BEST CHANCES WILL BE ALONG RIVER VALLEYS AND AREAS THAT RECEIVED RAIN EARLY TODAY AND TONIGHT. UPDATED GRIDS WITH LATEST OBS AND TRENDS WITH NO MAJOR CHANGES NEEDED AT THIS POINT. UPDATE ISSUED AT 1030 PM EDT SUN MAY 17 2015 THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN ISSUED. UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015 23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER... AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK. FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 300 PM EDT SUN MAY 17 2015 THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH 0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING. TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 300 PM EDT SUN MAY 17 2015 MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY NIGHT INTO EARLY THURSDAY. IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48 HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION. A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE IN THE WEEK...DY6 FRI. THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS. THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE END OF THE FORECAST WINDOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 135 AM EDT MON MAY 18 2015 TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY. WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP TOMORROW AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...AR LONG TERM...AR AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
135 AM EDT MON MAY 18 2015 .UPDATE... ISSUED AT 1030 PM EDT SUN MAY 17 2015 THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN ISSUED. UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015 23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER... AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK. FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 300 PM EDT SUN MAY 17 2015 THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH 0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING. TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 300 PM EDT SUN MAY 17 2015 MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY NIGHT INTO EARLY THURSDAY. IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48 HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION. A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE IN THE WEEK...DY6 FRI. THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS. THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE END OF THE FORECAST WINDOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 135 AM EDT MON MAY 18 2015 TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY. WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP TOMORROW AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...AR AVIATION...DJ
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
459 AM CDT MON MAY 18 2015 .SYNOPSIS... LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER THE REGION. && .DISCUSSION... MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA. RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA. HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING. RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA. WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE EAST OVER THE WEEKEND. THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING IN LOW-LYING OR URBAN AREAS. LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN THE MIDDLE 80S. && .MARINE... MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL DIMINISH DURING THE MORNING. OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT. && .PRELIMINARY POINT TEMPS/POPS... AEX 84 68 86 70 / 70 30 40 30 LCH 86 72 86 73 / 50 20 30 20 LFT 87 72 86 72 / 50 20 50 20 BPT 87 75 86 74 / 50 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT EXERCISE CAUTION UNTIL 9 AM CDT THIS MORNING FOR GMZ430-432-435-450-452-455-470-472-475. && $$ PUBLIC...24
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1154 PM CDT SUN MAY 17 2015 .AVIATION... REDEVELOPMENT OF TSTMS IS EXPECTED OVER THE NEXT FEW HOURS...WITH N LA TERMINALS MOST PRONE TO BE AFFECTED. CONVECTION IS EXPECTED AT LEAST INTERMITTENTLY FOR THE ENTIRE 06Z TAF PD. FOR TONIGHT...LIGHT WINDS AND MOIST SOILS FROM PREVIOUS RAINS WILL ALLOW FOR SOME PATCHY FOG DEVELOPMENT...ESPECIALLY WHERE CLOUDS ARE ABLE TO THIN OUT. ADDITIONALLY...PATCHY MVFR STRATUS WILL BE POSSIBLE AT A FEW OF THE TERMINALS AS WELL. OTHERWISE...EXPECT SLY WINDS GENERALLY LESS THAN 10 KTS THROUGHOUT THE PD. /12/ && .PREV DISCUSSION... /ISSUED 1032 PM CDT SUN MAY 17 2015/ UPDATE... TO MAKE ADJUSTMENTS TO THE RAIN CHANCES TONIGHT THROUGH MONDAY NIGHT AND CONTINUED THE THREAT FOR FLASH FLOODING FOR EAST AND NORTHEAST TEXAS...NORTHWEST AND NORTH CENTRAL LOUISIANA AND ADJACENT SOUTHWEST AND SOUTH CENTRAL ARKANSAS AND SOUTHEAST OKLAHOMA. DISCUSSION... A CONTINUED SOUTHERLY FLOW OF GULF MOISTURE TO GO ALONG WITH A CONTRIBUTING SUPPLY OF PACIFIC MOISTURE AND A SERIES OF UPPER LEVEL DISTURBANCES RIDING TOWARD THE FOUR STATE REGION WILL CONTINUE TO PROVIDE SHOWERS AND THUNDERSTORMS OVERNIGHT. SOME OF THE STORMS WILL DEVELOP AND SPREAD OVER THE SAME AREAS THAT HAVE HAD LOCALLY HEAVY RAIN LATELY RESULTING IN FLASH FLOODING. /06/ PREV DISCUSSION... /ISSUED 455 PM CDT SUN MAY 17 2015/ DISCUSSION... MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL- DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE DIFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT. HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0 INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE. AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY. THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH THE MAIN ATTENDANT TROUGH LIFTING NE INTO THE SRN ROCKIES BY EARLY TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH WILL HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE SRN PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH THE FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT TERM PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING SW INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING STATIONARY. PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE GFS...WHICH SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS ALOFT TO HELP DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP FOCUS SCT CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER ISOLATED TO WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY. HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE CLIMO THROUGH MUCH OF THE PERIOD. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 82 71 82 70 / 60 70 70 30 MLU 89 72 81 69 / 50 60 70 40 DEQ 79 68 83 67 / 80 50 40 40 TXK 80 70 83 68 / 80 60 50 40 ELD 84 70 81 68 / 60 70 70 40 TYR 78 71 82 69 / 80 60 50 30 GGG 78 70 82 69 / 80 70 60 30 LFK 81 72 82 71 / 80 40 70 30 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR ARZ050-051- 059>061-070>073. LA...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR LAZ001>006- 010>012. OK...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OKZ077. TX...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR TXZ096-097- 108>112-124>126-136>138-149>153. && $$ 12
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT MON MAY 18 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 508 AM EDT MON MAY 18 2015 WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING HRS. TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR (FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT. BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z TUE. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON MAY 18 2015 TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE 17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING. 850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT 12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH DIMINISHES SIGNIFICANTLY. EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF THE INTERIOR W HALF OF UPPER MI/. EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND 0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY /ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/. DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 137 AM EDT MON MAY 18 2015 RAIN IS PRETTY MUCH DONE UNTIL WRAPAROUND MOISTURE ARRIVES WITH SOME SHOWERS LATER MON AFTERNOON AND EVENING AT IWD AND CMX. VFR CONDITIONS WILL TRANSITION TO MVFR OVERNIGHT AT KIWD AND KCMX AS WRAPAROUND MOISTURE ASSOC WITH THE LOW COMES IN. WRAPAROUND MOISTURE WON`T REACH SAW UNTIL LATE MON AFTERNOON/EVENING SO EXPECT TRANSITION FROM VFR TO MVFR CONDITIONS TO OCCUR THERE LATER IN THE DAY. SAW WILL ALSO SEE A LAKE BREEZE MON AFTERNOON THAT WILL SWITCH THEIR WIND TO THE NORTHEAST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT MON MAY 18 2015 LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING AS COLDER AIR ARRIVES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...07 MARINE...VOSS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
515 AM EDT MON MAY 18 2015 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING WITH STACKED SURFACE AND UPPER LEVEL LOW OVER NORTHERN MINNESOTA CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE GREAT LAKES. DEWPOINTS RUNNING CLOSE TO 60F ACROSS WESTERN NEW YORK WITH MID 60S DEWPOINTS FOUND ACROSS MICHIGAN. SPC MESOSCALE ANALYSIS SHOWS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES RUNNING FROM NORTH OF GEORGIAN BAY TO LAKE ERIE. PLENTY OF MOISTURE TO BE FOUND SO FOCUS FOR TIMING OF SHOWER AND THUNDERSTORM ACTIVITY TODAY WILL BE ON ANY SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS THE EASTERN GREAT LAKES. A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS. TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A SECOND ROUND OF SHOWER/TSTM ACTIVITY. TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING MAXIMUM. OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH. TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW TO MID 50S. BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE 40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... IT WILL BE A DRY DAY ON THURSDAY WITH PASSING HIGH CLOUDS AS THE REGION WILL REMAIN UNDERNEATH THE FLATTENED BASE OF A DEEP UPPER LEVEL LOW CENTERED NEAR JAMES BAY. THE UPPER LEVEL FLOW WILL AMPLIFY ONCE MORE ACROSS THE AREA ON FRIDAY AS A JET MAX DROPS INTO THE BASE OF THE TROUGH OVER NORTHEASTERN ONTARIO. THIS WILL HELP PUSH ANOTHER WEAK COLD FRONT ACROSS UPSTATE AND WESTERN NEW YORK ON FRIDAY...POTENTIALLY TRIGGERING A SHOWER OR TWO ACROSS THE NORTH COUNTRY. HOWEVER...A LACK OF MOISTURE WILL ONCE AGAIN LIMIT POPS TO A SLIGHT CHANCE AT BEST. AN EVEN MORE BENIGN PATTERN TAKES SHAPE FOR THE COMING WEEKEND AS SURFACE HIGH PRESSURE TRACKS OVER THE LOWER GREAT LAKES. THERE WILL BE PLENTY OF SUNSHINE TO BE HAD FRIDAY AND SATURDAY AS THE HIGH MOVES OVERHEAD BEFORE MOVING OFF THE EAST COAST SUNDAY. AS THE HIGH MOVES OFF THE EAST COAST...LOOK FOR RETURN FLOW TO SET UP ACROSS THE LOWER GREAT LAKES THAT WILL SIGNAL A RETURN TO WARMER CONDITIONS SUNDAY WITH UNSETTLED WEATHER LIKELY TO FOLLOW BY MONDAY AS A WARM FRONT LIFTS NORTH ACROSS THE GREAT LAKES. REGARDING TEMPERATURES...READINGS WILL RUN IN THE 60S ON THURSDAY. WHILE CERTAINLY WARMER THAN THE CHILLY 50S EXPECTED WEDNESDAY...THE LOWER GREAT LAKES REGION WILL REMAIN CLOSE ENOUGH TO THE AFOREMENTIONED UPPER LEVEL LOW TO KEEP TEMPERATURES A FEW DEGREES BELOW NORMAL. INDEED THE PASSAGE OF THE WEAK COOL FRONT FRIDAY WILL KNOCK TEMPS BACK A COUPLE OF DEGREES. WITH HIGH PRESSURE MOVING BUILDING FRIDAY NIGHT AND COOL/DRY AIR IN PLACE...WE SHOULD SEE A CHILLY NIGHT WITH LOWS IN THE LOW/MID 40S...WITH UPPER 30S IN THE SOUTHERN TIER AND NORTH COUNTRY. THIS TIME WINDS MAY BE LIGHT ENOUGH TO POTENTIALLY ALLOW FOR FROST ACROSS THE SHELTERED AREAS OF THE NORTH COUNTRY AND THE SOUTHERN TIER. THEREAFTER...TEMPERATURES SHOULD GRADUALLY REBOUND THROUGH THE WEEKEND AS THE HIGH DRIFTS EAST OF THE REGION AND RETURN FLOW TAKES HOLD WITH WIDESPREAD 70S EXPECTED ONCE AGAIN BY SUNDAY. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS DURING THE LATE MORNING AND AFTERNOON AS A PRE-FRONTAL TROUGH CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE ERIE SHOULD KEEP KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL DEVELOP FROM THE SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND SYRACUSE. STORM ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH MAINLY DRY CONDITIONS EXPECTED TONIGHT. OUTLOOK... TUESDAY THROUGH FRIDAY...VFR. && .MARINE... LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS AND WAVES. A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST OF THE WEEK WITH LOW WIND AND WAVE ACTION. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040- 041. && $$ SYNOPSIS...SMITH NEAR TERM...SMITH SHORT TERM...WOOD LONG TERM...WOOD AVIATION...SMITH MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
444 AM EDT MON MAY 18 2015 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING WITH STACKED SURFACE AND UPPER LEVEL LOW OVER NORTHERN MINNESOTA CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE GREAT LAKES. DEWPOINTS RUNNING CLOSE TO 60F ACROSS WESTERN NEW YORK WITH MID 60S DEWPOINTS FOUND ACROSS MICHIGAN. SPC MESOSCALE ANALYSIS SHOWS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES RUNNING FROM NORTH OF GEORGIAN BAY TO LAKE ERIE. PLENTY OF MOISTURE TO BE FOUND SO FOCUS FOR TIMING OF SHOWER AND THUNDERSTORM ACTIVITY TODAY WILL BE ON ANY SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS THE EASTERN GREAT LAKES. A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS. TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A SECOND ROUND OF SHOWER/TSTM ACTIVITY. TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING MAXIMUM. OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH. TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW TO MID 50S. BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE 40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... THURSDAY AND FRIDAY...BROAD/FLAT UPPER LEVEL TROUGHING OVER THE GREAT LAKES AND NORTHEAST WILL REAMPLIFY AS A PAIR OF SHORTWAVES DROP THROUGH ITS BACKSIDE AND BASE...WITH AN ATTENDANT SECONDARY COLD FRONT PIVOTING ACROSS OUR REGION BETWEEN THURSDAY NIGHT AND FRIDAY. AT THIS JUNCTURE...THIS LATTER FEATURE STILL APPEARS TO BE TOO WEAK AND STARVED FOR BOTH MOISTURE AND UPPER LEVEL SUPPORT TO WARRANT THE INCLUSION OF ANY PRECIP CHANCES IN THE FORECAST...SO HAVE CONTINUED TO LEAVE THINGS DRY WITH SURFACE HIGH PRESSURE AND DRIER AIR CONTINUING TO DOMINATE OUR WEATHER. IN ADVANCE OF THE AFOREMENTIONED FRONT...SOME MODEST WARMING OF OUR AIRMASS SHOULD ALLOW TEMPS TO RECOVER BACK INTO THE LOWER AND MID 60S ON THURSDAY...BEFORE PULLING BACK AT LEAST A LITTLE BEHIND THE BOUNDARY ON FRIDAY. NEXT WEEKEND...SPRAWLING HIGH PRESSURE AND DRY AIR OVER OUR REGION AT THE START OF SATURDAY WILL SLOWLY DRIFT EASTWARD AND OFF THE ATLANTIC COASTLINE...WHILE HEIGHTS ALOFT ALSO REBUILD AS THE UPPER LEVEL TROUGH OVER OUR REGION LIFTS OUT...AND THE NEXT MODEST TROUGH BEGINS SLIDING EASTWARD ACROSS THE PLAINS STATES. UNDER THIS REGIME...DRY WEATHER SHOULD PERSIST THROUGH AT LEAST THE FIRST HALF OF SUNDAY...BEFORE AN APPROACHING WARM FRONT OVER THE OHIO VALLEY POTENTIALLY BRINGS A RISK OF SHOWERS SUNDAY AFTERNOON. THIS STATED...HAVE ELECTED TO KEEP THINGS DRY ON SUNDAY FOR NOW GIVEN BOTH THE DISTANT VANTAGE POINT AND THE LACK OF AGREEMENT EXHIBITED BY THE MEDIUM RANGE GUIDANCE WITH RESPECT TO THE TIMING OF THE WARM FRONT...WHICH IS TYPICAL FOR THIS FAR IN ADVANCE. WHAT IS MORE CERTAIN IS THAT THIS PATTERN SHOULD ALLOW FOR A WARMING TREND...WITH DAYTIME HIGHS CLIMBING BACK INTO THE 70S BY NEXT SUNDAY. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS DURING THE LATE MORNING AND AFTERNOON AS A PRE-FRONTAL TROUGH CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE ERIE SHOULD KEEP KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL DEVELOP FROM THE SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND SYRACUSE. STORM ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH MAINLY DRY CONDITIONS EXPECTED TONIGHT. OUTLOOK... TUESDAY THROUGH FRIDAY...VFR. && .MARINE... LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS AND WAVES. A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST OF THE WEEK WITH LOW WIND AND WAVE ACTION. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040- 041. && $$ SYNOPSIS...SMITH NEAR TERM...SMITH SHORT TERM...WOOD LONG TERM...JJR AVIATION...SMITH MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
110 AM CDT MON MAY 18 2015 .UPDATE... ISSUED AT 109 AM CDT MON MAY 18 2015 ROLLA SUSTAINED WIND AT 37 MPH GUSTING TO 48 MPH AND TURTLE MOUNTAIN RAWS AT 37 MPH WITH GUSTS TO 57 MPH. THESE VALUES ARE JUST BELOW HIGH WIND WARNING CRITERIA...AND LOOKING AT THE DECREASING TREND EXPECTED DURING THE OVERNIGHT HOURS - WILL ALLOW THE HIGH WIND WARNING FOR ROLETTE AND PIERCE COUNTIES TO EXPIRE. THE STRONG WINDS ARE IN THE WORDING OF THE WINTER WEATHER ADVISORY THAT IS IN EFFECT FOR NORTH CENTRAL NORTH DAKOTA - INCLUDING ROLETTE AND PIERCE COUNTIES. THIS IS IN EFFECT UNTIL 7 AM CDT MONDAY...AND FOR NOW WILL KEEP THE ADVISORY GOING. PRECIPITATION TRENDS ON REGIONAL RADARS INDICATE DECREASE IN AREAL COVERAGE AND INTENSITY. SHOULD THIS TREND CONTINUE THE WINTER WEATHER ADVISORY MAY BE DROPPED/ENDED BEFORE DAYBREAK. WILL WAIT A FEW HOURS FOR THAT DECISION. OTHERWISE WINDS ON TRACK WITH THE WIND ADVISORY GOING UNTIL 7 AM...AND WILL RE-EVALUATE IN A FEW HOURS. REST OF FORECAST ELEMENTS ON TRACK FOR THIS UPDATE. UPDATE ISSUED AT 1042 PM CDT SUN MAY 17 2015 ROLLA STILL SUSTAINED AT OVER 40KTS WITH TURTLE MOUNTAIN RAWS STILL GUSTING TO 61 MPH. WILL EXTEND THE HIGH WIND WARNING A COUPLE OF HOURS...TILL 1AM CDT. RAP PRESSURE RISES ON THE DECREASE SO A 1AM EXPIRATION SHOULD BE GOOD. UPDATE ISSUED AT 1004 PM CDT SUN MAY 17 2015 HEADLINES WILL REMAIN AS IS. AN ARGUMENT CAN BE MADE FOR A SMALL AREA FOR BLIZZARD HEADLINES WITH BOTH ROLLA AND HARVEY REPORTING STRONG WINDS GUSTING 35-45KTS AND 1/4 MILE VIS IN HEAVY SNOW. HOWEVER...VIS HAVE BEEN JUMPING FROM 1/4 TO 3/4 AND DO NOT FEEL THE SMALL AREA AND TIME DURATION JUSTIFIES AN UPGRADE. THUS WILL MAINTAIN THE WINTER WEATHER ADVISORY AS IS WITH NEAR BLIZZARD WORDING AND OTHER DIRE TERMINOLOGY IN THE OVERVIEW AND SEGMENT. HIGH WIND WARNING OVER MY FAR NORTHEAST EXPIRES AT 11PM. WILL REVISIT IN 30-45 MIN FOR A POSSIBLE EXTENSION. UPDATE ISSUED AT 710 PM CDT SUN MAY 17 2015 RAIN CHANGING OVER TO SNOW AS TEMPERATURES AT THE SURFACE AND ALOFT COOL. HAVE HAD A MIX OF SLEET SOUTH CENTRAL WHERE SOUNDINGS INDICATE A WARM LAYER ALOFT...COLD LAYER AROUND 850MB...AND SURFACE TEMPERATURES IN THE MIDDLE 30S. THE WARM LAYER WILL COOL WITH ALL SNOW BY 01-02Z. HEADLINES ALL STILL VALID...AND WILL STAY THE COURSE WITH THIS UPDATE. UPDATE ISSUED AT 608 PM CDT SUN MAY 17 2015 OPTED TO ISSUE A HIGH WIND WARNING OVER ROLETTE AND PIERCE COUNTIES. WINDS CONTINUE TO GUST OVER 60 MPH AT OBSERVING SITES ACROSS MY FAR NORTHEAST. CANNOT IGNORE THIS SO WENT WITH A WARNING. OTHER EDITS MINOR FOR NOW...ANOTHER UPDATE OUT BY 0030Z. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 330 PM CDT SUN MAY 17 2015 SIGNIFICANT STORM IMPACTING NORTH DAKOTA WILL BEGIN TO WANE TONIGHT AND EXIT THE REGION ON MONDAY. AS COLDER AIR WRAPS UP INTO THE SYSTEM SNOW WILL START TO ACCUMULATE ACROSS THE NORTH CENTRAL...WITH 2 TO NEAR 6 INCHES EXPECTED. STRONG WINDS WILL CONTINUE THROUGH THE NIGHT. WILL KEEP WIND ADVISORY THROUGH 7 PM NORTH CENTRAL THEN TRANSITION TO A WINTER WEATHER ADVISORY FOR THE SNOW AND MENTION THE STRONG WINDS IN THE WINTER WEATHER ADVISORY. WILL MAINTAIN WIND ADVISORY THROUGH THE NIGHT SOUTH CENTRAL. THE RAIN WILL SIGNIFICANTLY DECREASE AFTER MIDNIGHT. UNTIL THEN THERE IS A FLOOD ADVISORY FOR EAST CENTRAL NORTH DAKOTA WHERE WIDESPREAD WARM CONVEYER BELT PRECIP HAS BEEN QUASI STATIONARY TODAY. FINALLY...WIDESPREAD FREEZING TEMPERATURES ARE EXPECTED ACROSS WEST AND CENTRAL NORTH DAKOTA TONIGHT. WILL LET THE WINTER WEATHER ADVISORY AND ITS SNOW AMOUNTS STAND IN FOR THE FREEZE WARNING NORTH CENTRAL. ACROSS THE WEST AND SOUTH WILL ISSUE A FREEZE WARNING TONIGHT AND EARLY MONDAY. MONDAY WILL BECOME SUNNY WITH DIMINISHING WINDS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 PM CDT SUN MAY 17 2015 COOL AND DRY WILL CHARACTERIZE THE LONG TERM. HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING WEEKEND STORM MONDAY NIGHT. THIS WILL LEAD TO CLEAR SKIES AND LIGHT WIND. TEMPERATURES OVERNIGHT WILL LIKELY FALL INTO THE MID 20S FOR MOST OF NORTH DAKOTA. A FREEZE WARNING WILL BE POSSIBLE WITH WIDESPREAD FROST. THE REST OF THE WEEK LOOKS DRY WITH SURFACE HIGH PRESSURE REMAINING ENTRENCHED OVER NORTH DAKOTA AND UPPER LEVEL RIDING BUILDING WEST. THIS WILL KEEP MOST OF THE MOISTURE AND STORM TRACKS THIS WEEK SOUTH OF NORTH DAKOTA. TEMPERATURES LOOK TO REBOUND INTO THE 60S BY THURSDAY. THE NEXT CHANCE FOR PRECIPITATION ARRIVES THIS WEEKEND AS THE RIDGE BREAKS DOWN AND AN UPPER LEVEL LOW MOVES INTO THE PLAINS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 109 AM CDT MON MAY 18 2015 VFR AT KISN SHOULD PREVAIL THROUGH THE TAF PERIOD. KDIK SHOULD BE IMPROVING BY AROUND 09Z. WIDESPREAD MVFR CONDITIONS IN SNOW AND FOG AT KMOT/KBIS SHOULD CONTINUE THROUGH AROUND 12Z...THEN IMPROVE TO VFR. KJMS WILL LIKELY REMAIN AT MVFR AND IFR CONDITIONS UNTIL AROUND 00Z. SNOW SHOULD END AT KJMS BY AROUND 15Z BUT LARGE MVFR CLOUD SHIELD SHOULD REMAIN EAST OF KMOT/KBIS BUT ENCOMPASS KJMS THROUGH AROUND 00Z. && .HYDROLOGY... ISSUED AT 330 PM CDT SUN MAY 17 2015 HAVE ISSUED AN AREAL FLOOD ADVISORY THROUGH THIS EVENING EAST CENTRAL. RAINFALL AMOUNTS OF TWO TO 4 INCHES WITH SOME ISOLATED HIGHER AMOUNTS CAUSING PONDING...AND FLOODED FIELDS. CALLS AND INQUIRIES SO FAR HAVE REVEALED ROADS TO BE OK WITH SOME MINOR FLOODING. && .BIS WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR NDZ001-009-017>020-031>037-040>048-050-051. WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ THIS MORNING FOR NDZ019- 020-034>037-042-045>048-050-051. WINTER WEATHER ADVISORY UNTIL 7 AM CDT THIS MORNING FOR NDZ002>005-010>013-021>023-025. && $$ UPDATE...JV SHORT TERM...WAA LONG TERM...AJ AVIATION...JV HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1135 PM CDT SUN MAY 17 2015 .UPDATE... ISSUED AT 1135 PM CDT SUN MAY 17 2015 STILL HAVE WINDS NEAR WARNING CRITERIA WITHIN THE DEVILS LAKE BASIN...BUT MODEL GUIDANCE INDICATES 925MB WIND SPEEDS DECREASING 10 KNOTS FROM 03Z TO 06Z...SO ALLOWED HIGH WIND WARNING TO EXPIRE AT 11PM. WILL NEED TO WATCH THE NORTHERN VALLEY WITH DUE NORTH WINDS AND THE RAP INDICATING INCREASING 925MB WIND SPEEDS. GRAFTON AWOS IS CLOSE TO WARNING CRITERIA...AND WITH THE SFC PRESSURE GRADIENT STILL TIGHTENING CANNOT RULE OUT STRONG WINDS HERE. OTHERWISE...WINTER WEATHER ADVISORY AREA HAS REPORTS OF SNOW AND SLEET AND SLICK ROADS. ALSO HAD A REPORT OF 2.5 INCHES OF SNOW JUST N/NE OF ROLLA (IN CANADA). IMAGINE THAT THERE IS SOME SLUSHY ACCUMULATION INTO THE STATES. ELSEWHERE...RAIN HAS REDEVELOPED AS EXPECTED ACROSS NW MN (EVEN INTO THE VALLEY). && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 337 PM CDT SUN MAY 17 2015 FIRST OFF...SFC LOW NEAR SISSETON/WAHPETON AREA AT MID AFTN AND SFC PRESSURE FALLS ARE NOT CENTERED NEAR FOSSTON MN. SO SFC LOW WILL TACK NORTHEAST TOWARD THAT AREA THIS EVENING. EAST OF SFC LOW AREA IN DRY SLOT WHERE HEATING OCCURRED FAVORABLE FOR SOME THUNDERSTORM TO FORM. FOCUS IS FROM ALEXANDRIA NORTH TO EAST OF FERGUS FALLS....TO BEMIDJI...PARK RAPIDS AND WADENA. SFC AND UPPER AIR LOW PLACEMENT FAVORS LOW TOPPED SUPERCELLS WITH POSSIBLE FUNNEL FORMATION. PER SPC NOT EXPECTING WIDESPREAD STORMS THIS STRONG....BUT COULD BE THRU 00Z. ANOTHER QUESTION IS NW EDGE OF DEF ZONE PRECIP. RAIN FALLING PER PUBLIC LANGDON-DEVILS LAKE AREA STILL. MODELS TAKE DRIER AIR WEST AND WANT TO SHUT OFF DEF ZONE HEAVY PRECIP THIS EVENING LEAVING LIGHT PRECIP OVERNIGHT INTO MONDAY MORNING IN THE COLD AIR WHERE IT WILL BE COLD ENOUGH FOR SNOW. SO JUST HOW MUCH SNOW WILL FALL IS QUESTIONABLE. WILL LEAVE WSW OUT FOR 1-3 INCHES IN DVL BASIN-LANGDON AREAS OVERNIGHT AS TOO UNCERTAIN TO TINKER WITH IT. WINDS WILL BE A BIG FACTOR AND CONTINUE TO GUST IN THE 40-55 MPH RANGE IN DVL BASIN AND SPREAD INTO THE RRV THIS EVE. STRONG WINDS OVERNIGHT INTO MONDAY MORNING SO HAVE WIND ADVISORIES OUT. MOVED PRECIP OUT A BIT FASTER THAN EARLIER FCSTS MONDAY. OTHERWISE COLD AND WINDY. CLEARING OVERSPREADS AREA MON NIGHT AND LIKELY FREEZE CONDITIONS IN MANY AREAS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 337 PM CDT SUN MAY 17 2015 WELCOME DRY WEATHER TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES IN AND TEMPS BEGIN TO RECOVER. FOR WED NIGHT THROUGH SUNDAY...SMALL DISCUSSION TODAY DUE TO SEVERE WEATHER POTENTIAL. BASICALLY KEPT THE THU/FRI PERIOD DRY AND LEFT PCPN CHANCES AS THEY WERE FOR SAT/SUN. TEMPS LOOK TO RETURN TO NEAR NORMAL VALUES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1135 PM CDT SUN MAY 17 2015 LIFR/IFR CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT HOURS...WITH CONDITIONS GRADUALLY IMPROVING ON MONDAY. STRONG NORTH WINDS ALONG AND WEST OF THE VALLEY WILL GRADUALLY DIMINISH ON MONDAY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ008-016-026>030-038- 039-049-052>054. WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ006-007-014- 015-024. MN...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ001>004-007-029. && $$ UPDATE...TG SHORT TERM...RIDDLE LONG TERM...GODON/RIDDLE AVIATION...TG
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
213 AM EDT MON MAY 18 2015 .SYNOPSIS... WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON. && .NEAR TERM /THROUGH TONIGHT/... LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING. LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA. MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT OF SHOWERS AND STORMS TODAY. LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND POOR DRAINAGE AREAS. WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE THE THREAT OF SHOWERS AND STORMS. CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST. RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE FRONT STARTING TUESDAY NIGHT. DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST GIVING ZONAL FLOW FOR THE OHIO VALLEY. WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /THURSDAY THROUGH SUNDAY/... NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY. WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... 06Z MONDAY THRU 06Z TUESDAY... ALL OF THE SHOWERS AND STORMS HAVE MOVED OUT OF THE REGION...OR HAVE DISSIPATED. A FEW SHOWERS ARE STILL POSSIBLE DURING THE OVERNIGHT HOURS. VFR CONDITIONS PREVAILED IN MOST LOCATIONS. HOWEVER...MVFR/IFR CONDITIONS WERE OCCURRING ALONG SOME RIVER VALLEYS. CONDITIONS SHOULD REMAIN ROUGHLY ABOUT THE SAME THRU 12Z...WHEN CONDITIONS SHOULD IMPROVE AFTER SUNRISE. SEVERAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA TODAY...WHICH WILL RESULT IN THE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST LOCATIONS WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS ARE POSSIBLE NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO POSSIBLE NEAR THE STRONGER STORMS. THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED STORMS WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: COVERAGE OF FOG REMAINS IN QUESTION OVER WEST VIRGINIA THROUGH 12Z MON. HIGHLY VARIABLE CONDITIONS IN THE SHOWERS AND STORMS TODAY WITH CONDITIONS GOING LOWER THAN FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE MON 05/18/15 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY H H L L L L H H H M M H HTS CONSISTENCY H H H H H H H H H M H H BKW CONSISTENCY M H H H H H H H H M H H EKN CONSISTENCY L L L L L L H M H H M M PKB CONSISTENCY H H H H H H H H M M M H CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z TUESDAY... BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE MON NIGHT...AND IN LOW CLOUDS TUE MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/ARJ NEAR TERM...JSH SHORT TERM...FB LONG TERM...FB AVIATION...JSH
AREA FORECAST DISCUSSION
NWS TULSA OK
1139 PM CDT SUN MAY 17 2015 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. PATCHY FOG STILL EXPECTED LATE TONIGHT AS WINDS SUBSIDE AHEAD OF COLD FRONT...WHICH WILL MOVE INTO NORTHEAST OKLAHOMA MONDAY MORNING. THUNDERSTORM CHANCES APPEAR TO LOW AT THIS POINT TO MENTION ALONG/AHEAD OF FROPA. && .PREV DISCUSSION... /ISSUED 935 PM CDT SUN MAY 17 2015/ DISCUSSION... A MUCH QUIETER EVENING AS THE AREA HAS REMAINED PRECIP FREE FOR THE DURATION. BOUNDARY SEPARATING DEW POINTS IN UPPER 60S TO NEAR 70S FROM DRIER AIR EXTENDS FROM SOUTH CENTRAL OK INTO WESTERN OSAGE COUNTY AND NEAR THIS INTERFACE WITH LIGHT WINDS SOME FOG DEVELOPMENT REMAINS POSSIBLE. WARM MOIST SECTOR OVER WESTERN OK AND WESTERN AR REMAINS CAPPED AND SHORT RANGE GUIDANCE INCLUDING THE 00Z NAM TRENDING TOWARD A DRIER SOLUTION FOR TONIGHT. WILL KEEP SLIGHT CHANCE ACROSS FAR EASTERN/SOUTHERN AREAS AS A SUBTLE WAVER MOVES ACROSS TONIGHT AND MAY HAVE JUST ENOUGH LIFT TO SPARK A FEW SHOWERS LATE TONIGHT OR EARLY MON MORNING. UPDATED PRODUCTS WILL BE OUT SHORTLY. PREV DISCUSSION... /ISSUED 634 PM CDT SUN MAY 17 2015/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. SCATTERED TO BROKEN MID/HIGH CLOUDS WILL CONTINUE OVERNIGHT AS WEAK UPPER DISTURBANCE TRAVERSES THE AREA. COULD SEE SOME LIGHT FOG TOWARDS MORNING AS WINDS BECOME LIGHT AHEAD OF APPROACHING FRONTAL BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. PREV DISCUSSION... /ISSUED 359 PM CDT SUN MAY 17 2015/ DISCUSSION... NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER SHORT TERM HRRR LOOKS GOOD TONIGHT. NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST. CHANCE POPS THURSDAY INTO FRIDAY. UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY. ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND. GW && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...12
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1123 PM CDT SUN MAY 17 2015 .UPDATE... && .PREV DISCUSSION... /ISSUED 856 PM CDT SUN MAY 17 2015/ DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES INDICATE A MESOSCALE CONVECTIVE VORTEX /MCV/ OVER LOUISIANA. THIS MCV ALONG WITH A SUBTLE 700 MB SHORTWAVE TROUGH OVER THE LOWER MISSISSIPPI HAD RESULTED IN ADDITIONAL SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS THE MID SOUTH THIS EVENING...MAINLY WEST OF THE MISSISSIPPI RIVER. AS OF 8 PM CDT...TEMPERATURES ACROSS THE MID SOUTH ARE IN THE LOWER 70S AT MOST LOCATIONS. LATEST HRRR ALONG WITH THE 00Z WRF INDICATE POTENTIAL FOR RE- DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE MID SOUTH OVERNIGHT. WILL MAKE SOME ADJUSTMENTS TO POPS AND ALL OTHER ELEMENTS AS NEEDED FOR THE REMAINDER OF THE NIGHT. UPDATED GRIDS WILL BE AVAILABLE SHORTLY. CJC PREV DISCUSSION... /ISSUED 639 PM CDT SUN MAY 17 2015/ UPDATE...AVIATION DISCUSSION. PREV DISCUSSION... /ISSUED 304 PM CDT SUN MAY 17 2015/ THE MIDSOUTH REMAINS STUCK UNDERNEATH SOUTHWEST FLOW ALOFT. THE SOUTHWEST FLOW ALOFT HAS BROUGHT THIS WET PATTERN TO THE REGION AS THE COMBINATION OF SHORTWAVES MOVING THROUGH THE FLOW AND AN ABUNDANCE OF MOISTURE FROM THE GULF OF MEXICO HAS PRODUCED ROUND AFTER ROUND OF SHOWERS AND THUNDERSTORMS. LOOKING AT LATEST RADAR IMAGES...MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY HAS NOW PUSHED EAST OF THE MISSISSIPPI RIVER. MOST OF THIS CONVECTION WILL LIKELY PUSH EAST OF THE CWA BY 7 PM. HOWEVER...LATEST HRRR SHOWS REDEVELOPMENT OCCURRING OVER NORTHEAST ARKANSAS BY THAT TIME. THE CORRIDOR FROM NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL MAY SEE MOST OF THE CONVECTION DURING THE LATE EVENING INTO THE OVERNIGHT HOURS BEFORE IT SHIFTS SOUTHWARD ON MONDAY. HAVE ADJUSTED POPS ACCORDINGLY. IN ADDITION...SINCE THERE ARE PORTIONS OF NORTHEAST MISSISSIPPI THAT HAS SEEN SEVERAL ROUNDS OF HEAVY SHOWERS TODAY...WILL GO AHEAD AND EXPAND THE FLASH FLOOD WATCH SOUTHWARD TO COVER THE ENTIRE CWA THROUGH MONDAY. MONDAY WILL BE ANOTHER RAINY DAY FOR THE MIDSOUTH WITH OFF AND ON PERIODS OF HEAVY SHOWERS AND THUNDERSTORMS. EXPECT HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLD FRONT WILL FINALLY BEGIN TO PUSH INTO THE AREA MONDAY NIGHT INTO TUESDAY. MODELS ARE COMING INTO TO CLOSER AGREEMENT THAT THE FRONT WILL STALL OUT JUST SOUTH OF THE CWA AND BEGIN LIFTING BACK NORTHWARD AS A WARM FRONT LATE TUESDAY NIGHT INTO WEDNESDAY. THIS WILL KEEP SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR PORTIONS OF EAST-CENTRAL ARKANSAS AND NORTH MISSISSIPPI WHILE GIVING THE REST OF THE CWA ONLY A BRIEF REPRIEVE ON TUESDAY NIGHT. BY WEDNESDAY...THE ENTIRE MIDSOUTH WILL SEE CHANCES FOR SHOWERS AND THUNDERSTORMS AGAIN AS A WEAK SHORTWAVE MOVES ACROSS THE CWA. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL COME WEDNESDAY NIGHT INTO THURSDAY AS THE FRONT MOVES BACK THROUGH THE AREA AS A COLD FRONT. HIGH PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT THROUGH SATURDAY. NO PRECIPITATION IS EXPECTED AS A RESULT. HIGHS WILL BE IN THE MID 70S TO LOWER 80S. LOWS WILL BE IN THE MID 50S TO LOWER 60S. LOOKS LIKE THE MIDSOUTH COULD BE UNDERNEATH SOUTHWEST FLOW ALOFT AGAIN BY SATURDAY NIGHT CONTINUING INTO EARLY NEXT WEEK. THIS COULD BRING ANOTHER EXTENDED WET PERIOD TO THE REGION. KRM && .AVIATION...06Z TAFS MORE OF THE SAME OVER THE NEXT 24 HOURS....ALTHOUGH THIS LOOKS LIKE THE END OF SEVERAL DAYS OF DEALING WITH STORMS. PERIODS OF THUNDERSTORMS WILL RESULT IN BRIEF IFR VIS AND VARIABLE GUSTY WINDS. THE NEXT ROUND OF THUNDERSTORMS IS DEVELOPING IN SOUTHEAST ARKANSAS AND NORTHWEST MISSISSIPPI...TRACKING TOWARD THE NORTHEAST. FEEL CONFIDENT ENOUGH THAT THEY WILL IMPACT MEM AND MKL TO ADD A PREVAILING THUNDER GROUP FOR A COUPLE OF HOURS STARTING AT 06 AND 0730Z RESPECTIVELY. SHORT RANGE MODELS INDICATE ANOTHER YET ROUND OF TSRAS WILL FIRE UP AFTER MIDNIGHT...SHIFTING ACROSS JBR...MEM...AND MKL PRIOR TO SUNRISE. MODELS DISAGREE ON HOW WIDESPREAD LOW CLOUDS LATER TONIGHT AND MON MORNING. BEST CHANCES APPEAR TO BE AT KTUP AND PLACED A MVFR CIG THERE MONDAY MORNING OTRW WILL GO WITH OPTIMISTIC FORECAST. ANOTHER ROUND OF DAYTIME HEATING DRIVEN STORMS IS EXPECTED TOMORROW. WILL CARRY TEMPO VCTS AT ALL SITES FOR MOST OF THE AFTERNOON. SOUTH WINDS 10-12 KTS WITH HIGHER GUSTS THIS AFTN...8-10 KTS TONIGHT. WINDS SHOULD BEGIN TO SHIFT MORE WESTERLY OR NORTHWESTERLY BY SUNSET TOMORROW...AND PRECIPITATION SHOULD COME TO AN END AFTER SUNSET. 30 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR CLAY-CRAIGHEAD- CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI- PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS. MO...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR DUNKLIN-PEMISCOT. MS...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR ALCORN-BENTON MS- CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS- MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN- TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA. TN...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR BENTON TN-CARROLL- CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN- HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON- MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY. && $$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
340 AM CDT MON MAY 18 2015 .SHORT TERM... THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY AS LATE THIS AFTN. THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS. COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES INDEED OCCUR. ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00- 1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS. WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40 KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY THREATS/. A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND 80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S. .LONG TERM... THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL BEGIN TO THIN FROM WEST TO EAST. WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM. THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD AND THEN RETREATS FRIDAY AND SATURDAY. TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE CAA ASSOCIATED WITH THE FROPA. ALDRICH && .PRELIMINARY POINT TEMPS/POPS... FRIONA 78 55 71 49 / 10 80 90 20 TULIA 79 57 69 51 / 10 80 90 40 PLAINVIEW 79 58 70 53 / 10 80 90 40 LEVELLAND 83 60 74 56 / 20 80 90 30 LUBBOCK 83 61 73 57 / 10 80 90 40 DENVER CITY 82 61 76 60 / 30 80 80 20 BROWNFIELD 84 61 74 59 / 20 80 90 30 CHILDRESS 86 63 71 60 / 10 60 90 60 SPUR 84 63 73 61 / 10 70 90 50 ASPERMONT 87 66 75 64 / 10 70 90 50 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 29/51
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
329 AM CDT MON MAY 18 2015 .SHORT TERM... THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY AS LATE THIS AFTN. THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS. COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES INDEED OCCUR. ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00- 1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS. WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40 KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY THREATS/. A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND 80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S. .LONG TERM... THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES SHOW ALL LIFT AND NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL BEGIN TO THIN FROM WEST TO EAST. WE SHOULD SEE PRECIP MOVE OFF THE THE EAST BY WED MORNING AS A FRONT APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN WIND SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW TO OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM. THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD AND THEN RETREATS FRIDAY AND SATURDAY. TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE CAA ASSOCIATED WITH THE FROPA. ALDRICH && .PRELIMINARY POINT TEMPS/POPS... FRIONA 78 55 71 49 / 10 80 90 20 TULIA 79 57 69 51 / 10 80 90 40 PLAINVIEW 79 58 70 53 / 10 80 90 40 LEVELLAND 83 60 74 56 / 20 80 90 30 LUBBOCK 83 61 73 57 / 10 80 90 40 DENVER CITY 82 61 76 60 / 30 80 80 20 BROWNFIELD 84 61 74 59 / 20 80 90 30 CHILDRESS 86 63 71 60 / 10 60 90 60 SPUR 84 63 73 61 / 10 70 90 50 ASPERMONT 87 66 75 64 / 10 70 90 50 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 29/51
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1136 PM CDT SUN MAY 17 2015 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 608 PM CDT SUN MAY 17 2015 STORMS HAVE DIMINISHED IN INTENSITY AND COVERAGE THE LAST FEW HOURS OVER THE FORECAST AREA. MESO DATA SUGGESTS THE REGION OF POTENTIAL NEW DEVELOPMENT OF STORMS LIKELY OVER THE NORTHWEST HALF OF THE STATE...INCLUDING PARTS OF CENTRAL AND NORTH CENTRAL WISCONSIN WITH THE BEST SHEAR VALUES...AND STEEP SURFACE LAPSE RATES. ANTICIPATE THE SURFACE LAPSE RATES TO BE ON THE DECLINE THE NEXT FEW HOURS...SO THE THREAT OF STRONG TO SEVERE STORMS SHOULD LESSON. SPIRALING BANDS OF CONVECTION OVER EASTERN MINNESOTA AND FAR WESTERN WISCONSIN CLOSER TO THE LOW PRESSURE AREA OVER NORTHERN MINNESOTA MAY ROTATE INTO THIS ENVIRONMENT AND INTENSIFY OVER NORTH CENTRAL WISCONSIN THIS EVENING. && .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 229 PM CDT SUN MAY 17 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED LOW PRESSURE SYSTEM SPINNING OVER THE EASTERN DAKOTAS. SHORTWAVES ARE ROTATING NORTHWARD AHEAD OF THIS OCCLUDED CYCLONE...THE STRONGEST OF WHICH IS LOCATED OVER EASTERN IOWA. A PWAT AXIS IS MOVING ACROSS WISCONSIN EARLY THIS AFTERNOON...WHICH COMBINED WITH MOISTURE CONVERGENCE...IS CONTRIBUTING TO SCATTERED SHOWER DEVELOPMENT OVER CENTRAL WISCONSIN. CLOUD COVER HAS SIGNIFICANTLY SLOWED THE HEATING CURVE SO FAR TODAY...KEEPING ML CAPES BELOW 200 J/KG. WITH SHOWER COVERAGE EXPECT TO INCREASE THROUGH THE AFTERNOON...IT WILL BE TOUGH TO SEE MUCH OF AN INCREASE OF INSTABILITY. STILL THOUGH...RADAR ECHOES SUGGEST SOME THUNDERSTORMS WILL BE POSSIBLE...AND ANY STORMS COULD BRING DOWN STRONG WINDS FROM ALOFT. WILL HAVE TO KEEP A MENTION OF ISOLATED DAMAGING WINDS THROUGH EARLY THIS EVENING. OTHERWISE...THE LATEST HRRR CONGEALS THE SHOWER ACTIVITY INTO BAND AND PROGRESSES IT ACROSS THE FORECAST AREA FOR THE REST OF THE AFTERNOON. TONIGHT...LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN MINNESOTA...WHILE A COLD FRONT WILL PUSH EAST THROUGH ALL BUT FAR EASTERN WISCONSIN OVERNIGHT. THOUGH SHORTWAVE ENERGY WILL BE ROTATING NORTHEAST OVER NORTHWEST WISCONSIN THROUGH THE EVENING...CONCERNED THAT STRONG DRYING AND INCREASING CAPPING IN THE MID-LEVELS WILL EVEN FURTHER LIMIT THUNDERSTORM POTENTIAL FOR THE FIRST COUPLE HOURS IN THE EVENING. WILL KEEP A MENTION OF ISOLATED DAMAGING WINDS THROUGH 02Z IN CASE SOME THUNDERSTORMS MAKE A RUN INTO N-C WISCONSIN FROM MINNESOTA. ONCE THE THREAT OF STORMS ENDS...MODELS SHOW CLEARING TAKING PLACE UNTIL LOW CLOUDS FLOOD EAST BEHIND THE COLD FRONT LATE TONIGHT. LOW TEMPS NEAR 60 OVER THE EAST...BUT COOLING TO NEAR 50 OVER THE WEST. MONDAY...OCCLUDED LOW PRESSURE WILL BE WEAKENING AS IT MOVES TO THE EAST ACROSS LAKE SUPERIOR. WEST WINDS ON THE SOUTHERN FLANK OF THE LOW WILL BE COLD ADVECTING THROUGH THE DAY...WHILE PUSHING IN WRAP AROUND MOISTURE. SHOULD SEE AMPLE CLOUD COVER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THROUGH THE DAY...BUT EAST-CENTRAL WISCONSIN WILL LIKELY SEE SOME SUN IN THE MORNING BEFORE CLOUDS INCREASE IN THE AFTERNOON. WITH THE SUNSHINE...TEMPS SHOULD WARM TO NEAR 70 IN THE EAST...BUT ONLY INTO THE MID AND UPPER 50S OVER THE WEST. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 229 PM CDT SUN MAY 17 2015 MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK...DRY AND MILDER CONDITIONS FOR THE LATTER HALF...AND A POSSIBLE RETURN TO WET WEATHER LATER IN THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST CONCERNS. THE REMNANTS OF THE UPPER LOW WILL TRACK ACROSS NORTHERN LAKE SUPERIOR ON MONDAY NIGHT...FOLLOWED BY A S/W TROF PASSING NORTH OF WI ON TUESDAY. UNSEASONABLY COLD AIR (H8 TEMPS -8 TO -10 C) WILL FLOW INTO THE REGION ON NNW WINDS...SETTING THE STAGE FOR SOME LAKE-ENHANCED SHOWERS OVER NC WI. LOW-LEVEL TEMPS AND THICKNESSES SUPPORT A MIX THEN CHANGEOVER TO SNOW LATE MONDAY NIGHT INTO TUESDAY MORNING...WITH LITTLE OR NO ACCUMULATION EXPECTED. ANY LINGERING PCPN SHOULD END TUESDAY AFTERNOON AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION. HIGH PRESSURE WILL COVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. STILL EXPECTING FROST TUESDAY NIGHT...BUT GETTING A LITTLE CONCERNED ABOUT THE POSSIBILITY OF THICKER HIGH LEVEL CLOUDS...DUE TO THE PRESENCE OF A STRONG JET STREAK OVER THE REGION. RIGHT NOW...HAVE JUST BUMPED UP CLOUD COVER A BIT OVER C/EC WI...BUT KEPT MOSTLY CLEAR SKIES OVER NORTHERN WI. WILL CONTINUE TO CARRY WIDESPREAD FROST OR FREEZE CONDITIONS OVER NORTHERN WI...AND PATCHY FROST OVER MOST OF C/EC WI. A WEAK BACK DOOR COLD FRONT WILL SAG THROUGH THE FORECAST AREA THURSDAY INTO THURSDAY NIGHT...BUT WILL NOT HAVE ANY MOISTURE TO WORK WITH...SO DRY WEATHER WILL PREVAIL. BEHIND THE FRONT...CANADIAN HIGH PRESSURE WILL REESTABLISH ITSELF OVER THE WESTERN GREAT LAKES...AND IS EXPECTED TO LINGER INTO SATURDAY. ABUNDANT SUNSHINE SHOULD BRING A RETURN TO NEAR NORMAL TEMPERATURES FOR THE LATTER HALF OF THE WEEK. AN UPPER TROF...LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL IMPACT THE REGION FROM SATURDAY NIGHT INTO SUNDAY. GULF MOISTURE IS EXPECTED TO FLOW INTO THE REGION AHEAD OF THE FRONT...WITH PRECIPITABLE WATER VALUES REACHING 1.00-1.25 INCHES. HAVE RAMPED POPS UP TO LIKELY FOR SUNDAY. THE ECMWF PULLS MOST OF THE PCPN OUT OF THE REGION SUNDAY EVG...WHILE THE GFS HANGS ONTO SIGNIFICANT QPF INTO MEMORIAL DAY...SO FCST CONFIDENCE WANES BEYOND SUNDAY. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1135 PM CDT SUN MAY 17 2015 LAST OF THE SHOWERS WERE DEPARTING FAR NORTH CENTRAL WISCONSIN LATE THIS EVENING. OTHERWISE VFR CONDITIONS TO PREVAIL OVERNIGHT ALONG WITH LLWS CONDITIONS. LLWS CONDITIONS WILL END MONDAY MORNING BUT BLUSTERY WEST SURFACE WINDS WILL DEVELOP. WRAP AROUND MVFR CIGS DUE TO THE DEPARTING UPPER LOW SYSTEM WILL BEGIN TO WORK INTO CENTRAL AND NORTH CENTRAL WISCONSIN MONDAY MORNING. CIGS WILL CONTINUE TO WORK INTO EASTERN AREAS BUT WILL MORE OF THE LOWER END VFR CIGS. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........TDH SHORT TERM.....MPC LONG TERM......KIECKBUSCH AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1029 AM EDT MON MAY 18 2015 .SYNOPSIS... ISSUED AT 1024 AM EDT MON MAY 18 2015 A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH TEMPERATURES THIS AFTERNOON WILL BE MAINLY IN THE LOWER 80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO LOWER 50S. HIGHS TUESDAY AND WEDNESDAY WILL RANGE FROM THE MID 50S TO LOWER 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 358 AM EDT MON MAY 18 2015 DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500 J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY IN ASSOCIATION WITH SOUTHERN STREAM. ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION. EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION LATER THIS AFTERNOON/THIS EVENING. SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR WILL BE POST-FRONTAL. SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL EXPERIENCE CLEARING SKIES IN THE EVENING. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 358 AM EDT MON MAY 18 2015 TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD. SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID 30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE FORECAST AT THIS POINT AND CONTINUE TO MONITOR. ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 637 AM EDT MON MAY 18 2015 MVFR CIGS TO LINGER THIS MORNING AT KFWA...BUT SHOULD TREND TO VFR BY THE 14Z OR 15Z TIMEFRAME WITH DIURNAL WARMING. MAIN FEATURE OF INTEREST FOR TODAY WILL BE APPROACHING COLD FRONTAL BOUNDARY THAT MAY TRIGGER SOME ISOLATED OR SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS. LOW LEVEL MIXING IN THE AFTERNOON MAY TEND TO DISCOURAGE LARGE MAGNITUDES TO AFTERNOON INSTABILITY HOWEVER...SO CONFIDENCE REMAINS LOW ON THUNDER PROBABILITIES AT KFWA. INSTABILITY EVEN LESS SUBSTANTIAL AT KSBN...SO WILL CONTINUE TO OMIT ANY PRECIP MENTION. LIGHT SOUTH SOUTHWEST WINDS THIS MORNING WILL BECOME GUSTY INTO THE 15 TO 22 KNOT RANGE THIS AFTERNOON AHEAD OF THE FRONT...WITH A WIND SHIFT TO THE WEST OR WEST NORTHWEST FOR LATE AFTERNOON/EARLY EVENING BEHIND THE COLD FRONT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY FOR LMZ043-046. && $$ SYNOPSIS...SKIPPER SHORT TERM...MARSILI LONG TERM...AGD AVIATION...MARSILI/SKIPPER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
646 AM EDT MON MAY 18 2015 .SYNOPSIS... ISSUED AT 358 AM EDT MON MAY 18 2015 A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE UPPER 70S TO LOWER 80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO LOWER 50S. HIGH TEMPERATURES ON TUESDAY AND WEDNESDAY WILL RANGE FROM THE MID 50S TO LOWER 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 358 AM EDT MON MAY 18 2015 DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500 J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY IN ASSOCIATION WITH SOUTHERN STREAM. ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION. EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION LATER THIS AFTERNOON/THIS EVENING. SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR WILL BE POST-FRONTAL. SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL EXPERIENCE CLEARING SKIES IN THE EVENING. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 358 AM EDT MON MAY 18 2015 TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD. SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID 30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE FORECAST AT THIS POINT AND CONTINUE TO MONITOR. ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 637 AM EDT MON MAY 18 2015 MVFR CIGS TO LINGER THIS MORNING AT KFWA...BUT SHOULD TREND TO VFR BY THE 14Z OR 15Z TIMEFRAME WITH DIURNAL WARMING. MAIN FEATURE OF INTEREST FOR TODAY WILL BE APPROACHING COLD FRONTAL BOUNDARY THAT MAY TRIGGER SOME ISOLATED OR SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS. LOW LEVEL MIXING IN THE AFTERNOON MAY TEND TO DISCOURAGE LARGE MAGNITUDES TO AFTERNOON INSTABILITY HOWEVER...SO CONFIDENCE REMAINS LOW ON THUNDER PROBABILITIES AT KFWA. INSTABILITY EVEN LESS SUBSTANTIAL AT KSBN...SO WILL CONTINUE TO OMIT ANY PRECIP MENTION. LIGHT SOUTH SOUTHWEST WINDS THIS MORNING WILL BECOME GUSTY INTO THE 15 TO 22 KNOT RANGE THIS AFTERNOON AHEAD OF THE FRONT...WITH A WIND SHIFT TO THE WEST OR WEST NORTHWEST FOR LATE AFTERNOON/EARLY EVENING BEHIND THE COLD FRONT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY FOR LMZ043-046. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...AGD AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS JACKSON KY
938 AM EDT MON MAY 18 2015 .UPDATE... ISSUED AT 938 AM EDT MON MAY 18 2015 JUST MADE SOME ADJUSTMENTS TO THE FORECAST GRIDS THROUGH THE REST OF THE MORNING. BASED ON CURRENT RADAR IMAGERY...POPS IN OUR SOUTHWESTERN AND WESTERN COUNTIES NEEDED TO BE INCREASED. WENT THROUGH AND INCREASED HOURLY POPS OVER THE NEXT 4 HOURS BY 10 TO 15 PERCENT TO ACCOUNT FOR REAL TIME TRENDS. THIS DID NOT CHANGE THE WORDING IN THE ZONE FORECAST TEXT PRODUCT SO NO UPDATE TO THAT WAS NECESSARY. IN SUMMARY...THE POP...POP12...AND WEATHER TYPE GRIDS HAVE ALL BEEN UPDATED. UPDATE ISSUED AT 709 AM EDT MON MAY 18 2015 A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING. STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON MAY 18 2015 03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY. THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND 17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE THIS AFTERNOON. ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 434 AM EDT MON MAY 18 2015 SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS. HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT. ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND. LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL BE TO OUR WEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 657 AM EDT MON MAY 18 2015 FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN. A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING. OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP TO 15 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...DJ LONG TERM...HAL AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
709 AM EDT MON MAY 18 2015 .UPDATE... ISSUED AT 709 AM EDT MON MAY 18 2015 A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING. STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON MAY 18 2015 03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY. THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND 17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE THIS AFTERNOON. ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 434 AM EDT MON MAY 18 2015 SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS. HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT. ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND. LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL BE TO OUR WEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 657 AM EDT MON MAY 18 2015 FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN. A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING. OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP TO 15 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...DJ LONG TERM...HAL AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
657 AM EDT MON MAY 18 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON MAY 18 2015 03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY. THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND 17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE THIS AFTERNOON. ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 434 AM EDT MON MAY 18 2015 SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS. HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT. ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND. LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL BE TO OUR WEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 657 AM EDT MON MAY 18 2015 FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN. A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING. OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP TO 15 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...HAL AVIATION...DJ
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1004 AM CDT MON MAY 18 2015 .DISCUSSION... SLOW MOVING MCS ACROSS E TX/C LA WILL BE THE MAIN CONCERN THIS MORNING...ESPECIALLY FOR FLASH FLOOD POTENTIAL ACROSS THIS REGION. FOR THIS...ISSUED FLASH FLOOD WATCH FOR TYLER & N JASPER/NEWTON COUNTIES IN SE TX...AND VERNON/RAPIDES/AVOYELLES PARISHES IN C LA. HIGH POPS REMAIN FOR THE REST OF THE AFTERNOON FROM THE I-10 CORRIDOR NORTHWARD. FURTHER SOUTH SOUTH OF THE I-10 CORRIDOR...POPS DROP OFF SIGNIFICANTLY AT THIS TIME...BUT WILL HAVE TO WATCH IF ANY ADDITIONAL OUTFLOW BOUNDARIES MAY GENERATE PRECIP LATER THIS EVENING AND OVERNIGHT ACROSS THIS REGION. DML && .PREV DISCUSSION... /ISSUED 701 AM CDT MON MAY 18 2015/ DISCUSSION... FOR THE 12Z TAF PACKAGE. AVIATION... ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC 4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS STRONG AND/OR GUSTY AS YESTERDAY. 13 PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/ SYNOPSIS... LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER THE REGION. DISCUSSION... MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA. RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA. HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING. RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA. WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE EAST OVER THE WEEKEND. THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING IN LOW-LYING OR URBAN AREAS. LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN THE MIDDLE 80S. 24 MARINE... MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL DIMINISH DURING THE MORNING. OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT. 24 && .PRELIMINARY POINT TEMPS/POPS... AEX 84 68 86 70 / 80 30 40 30 LCH 86 72 86 73 / 50 20 30 20 LFT 87 72 86 72 / 40 20 50 20 BPT 87 75 86 74 / 50 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>029. TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR TXZ180-259-260. GM...NONE. && $$ PUBLIC...04
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
701 AM CDT MON MAY 18 2015 .DISCUSSION... FOR THE 12Z TAF PACKAGE. && .AVIATION... ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC 4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS STRONG AND/OR GUSTY AS YESTERDAY. 13 && .PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/ SYNOPSIS... LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER THE REGION. DISCUSSION... MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA. RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA. HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING. RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA. WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE EAST OVER THE WEEKEND. THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING IN LOW-LYING OR URBAN AREAS. LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN THE MIDDLE 80S. 24 MARINE... MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL DIMINISH DURING THE MORNING. OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT. 24 && .PRELIMINARY POINT TEMPS/POPS... AEX 84 68 86 70 / 70 30 40 30 LCH 86 72 86 73 / 50 20 30 20 LFT 87 72 86 72 / 50 20 50 20 BPT 87 75 86 74 / 50 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT EXERCISE CAUTION UNTIL 9 AM CDT THIS MORNING FOR GMZ430-432-435-450-452-455-470-472-475. && $$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
948 AM EDT MON MAY 18 2015 .UPDATE... ISSUED AT 947 AM EDT MON MAY 18 2015 A STRONG COLD FRONT IS OVER EASTERN WI THIS MORNING. TEMPS ARE PUSHING 70F ALONG THE WI LAKE MI COAST...BUT ARE IN THE LOW 40S IN THE NW CORNER OF THE STATE. THERE IS NO PRECIP ALONG THE FRONT...IN FACT THERE IS NO CLOUD COVER ALONG THE FRONT...THOUGH POST-FRONTAL CLOUD COVER IS SUBSTANTIAL. CLOSER TO HOME...PATCHY MID/HIGH CLOUDS ARE SEEN OVER NORTHERN MI...A BIT THICKER ACROSS EASTERN UPPER. A COUPLE OF POINTS OF CONCERN TODAY. THE COLD FRONT WILL CROSS THE REGION THIS AFTERNOON. ANY POTENTIAL CONVECTION ALONG IT LOOKS TO BE CONFINED TO THE EXTREME SE...AS A GENERAL LACK OF FORCING AND WARM TEMPS ALOFT WILL PROVE A SIGNIFICANT OBSTACLE. WE MIGHT BE ABLE TO MUSTER 500J/KG OF SBCAPE IN FAR SE SECTIONS. THE MOST RECENT HRRR AND RUC RUNS DO TRY TO POP SOMETHING EARLY THIS AFTERNOON...BEFORE DRIER AIR ARRIVES LATER IN THE DAY. HAVE ADDED A SLIGHT CHANCE OF A SHRA EARLY/MID AFTERNOON FROM OSC TO STANDISH. THE OTHER ISSUE IS ANY POTENTIAL FIRE WX CONCERNS. JUST BEHIND A COLD FRONT IS A CLASSIC SUMMER FIRE WX PATTERN FOR US...AS WITH STRONG HEATING WE TEND TO DRY OUT FASTER THAN WE COOL OFF. HOWEVER... IDEALLY COLD FROPA WOULD HAPPEN A FEW HOURS EARLIER...IN THE MORNING AS OPPOSED TO THE PM. HAVE LOWERED DEW POINTS A BIT DURING THE AFTERNOON...BUT HAVE ALSO DONE THE SAME TO LATE-DAY TEMPS AS THE COOLER AIR MAKES INITIAL INROADS. SO DON/T HAVE RH LEVELS GOING BELOW 35 PERCENT OR SO. && .NEAR TERM...(TODAY THROUGH TONIGHT) ISSUED AT 319 AM EDT MON MAY 18 2015 ALL REMAINING SHOWERS HAVE EXITED NE OUT OF OUR CWA EARLY THIS MORNING...WITH NO ADDITIONAL SHOWER ACTIVITY CURRENTLY PRESENT UPSTREAM AS THE WRN GREAT LAKES REMAINS FIRMLY WITHIN THE DRY SLOT ASSOCIATED WITH DEEP LOW PRESSURE NOW CENTERED OVER NRN MINNESOTA. SKIES HAVE AT LEAST PARTIALLY CLEARED IN RESPONSE TO THIS DRIER AIR WORKING ITS WAY INTO MICHIGAN. OUR CWA WILL REMAIN WITHIN THE DRY SLOT THRU MUCH OF TODAY AS THE SURFACE LOW CENTER MAKES SLOW EASTWARD PROGRESS THRU UPPER MICHIGAN AND INTO QUEBEC BY 00Z TUESDAY. EXPECT A PARTLY TO MOSTLY SUNNY AND DRY DAY ALONG WITH UNSEASONABLY WARM TEMPS FOR MOST OF OUR CWA. AFTERNOON HIGHS WILL ONLY REACH TO AROUND 70 DEGREES ACROSS ERN UPR MICHIGAN WHERE CAA ON THE BACKSIDE OF THE LOW WILL INITIALLY BEGIN THIS AFTERNOON. BUT TEMPS WILL ONCE AGAIN WARM INTO THE UPPER 70S AND LOWER 80S FOR NRN LWR MICHIGAN (COOLER NEAR THE LAKES)...GIVING US ONE LAST DAY OF SUMMER WARMTH BEFORE THE REALITY OF NRN MICHIGAN IN MID MAY KICKS BACK IN ON TUESDAY. LOW LEVEL MOISTURE/CLOUDS WILL WRAP BACK INTO NRN MICHIGAN TONIGHT ON THE BACKSIDE OF THE DEPARTING LOW. THE CAA BEHIND THE LOW WILL BE RAPID AND IMPRESSIVE THRU THE NIGHT...AS 850 MB TEMPS DROP FROM +13C THIS AFTERNOON TO AROUND -2C BY 12Z TUESDAY. AT THIS POINT...THINK THE ONLY LOCATION THAT WILL SEE A CHANCE OF SHOWERS WILL BE NW CHIPPEWA COUNTY THIS AFTERNOON AND TONIGHT WHERE CAA AND LOW LEVEL WRAP AROUND MOISTURE ADVECTION TAKE PLACE SOONEST. THE REST OF OUR CWA SHOULD BE GENERALLY DRY...BUT WITH DEEP CYCLONIC FLOW... INCREASING LOW LEVEL MOISTURE AND EVENTUALLY SOME OVER-LAKE INSTABILITY DEVELOPING LATE TONIGHT THANKS TO CAA...WILL NEED TO KEEP AN EYE ON THE POTENTIAL FOR SOME SHOWER ACTIVITY TO DEVELOP. FOR NOW...WILL MAINTAIN A DRY FORECAST WITH INCREASING CLOUDS TONIGHT. TEMPS WILL BE NOTICEABLY COLDER TONIGHT...WITH LOWS FALLING MAINLY INTO THE 40S. && .SHORT TERM...(TUESDAY THROUGH WEDNESDAY NIGHT) ISSUED AT 319 AM EDT MON MAY 18 2015 HIGH IMPACT WEATHER: TUESDAY NIGHT LOW TEMPERATURES/FROST POTENTIAL FOR N LOWER. FORECAST CHALLENGE: HOW FAR WILL THE TEMPERATURES FALL TUESDAY NIGHT. (05/19)TUESDAY...WITH THE FRONT SEVERAL HUNDRED MILES TO THE EAST, THE COLD AIR WILL BE PUSHING INTO THE REGION THROUGH THE DAY. TEMPERATURES WILL PRETTY MUCH GO NO WHERE AS THE 850 MB TEMPERATURES FALL FROM AROUND 0C TO ABOUT -4 OR -6C DEPENDING ON THE MODEL. THE ECMWF IS BEGINNING TO BACK OFF ON THE -8C AIR THAT IT WAS ADVERTISING THE LAST 2 RUNS, WITH IT AROUND -6C AT ANJ. WHILE THE GFS WILL BE AROUND -4C. WILL HAVE A MIX OF RAIN AND SNOW IN THE AFTERNOON AS THE SFC TEMPERATURES BEGIN TO FALL INTO THE UPPER 30S BY IN E UPPER. THE MOISTURE DOESN`T LOOK DEEP ENOUGH FOR PRECIPITATION IN N LOWER SO WILL LEAVE IT OUT OF THERE, JUST MOSTLY CLOUDY. OVERNIGHT, THE RH AT 850 MB AND IN THE 700-500 MB LAYER WILL DROP TO LESS THAN 20% ON BOTH MODELS BY 12Z. AND WITH THE 850 MB TEMPERATURES MAINTAINING AROUND 0C OR BELOW, AND, AT LEAST ON THE ECMWF, THE WINDS WILL PROBABLY DECOUPLE, FROST IS PROBABLE, AND MAYBE A FREEZE IS POSSIBLE. FOR NOW WILL HAVE PATCHY AND AREAS OF FROST, BUT THIS IS LOOKING MORE WIDE SPREAD IF THE WINDS DROP OFF LIKE THE ECMWF WOULD SUGGEST. (05/20)WEDNESDAY...LOOKS TO BE A SUNNY TO PARTLY CLOUDY DAY WITH LOW RELATIVE HUMIDITY AND HIGH TEMPERATURES, BELOW NORMAL (LOOKS LIKE NOW AROUND 5 TO 10 DEGREES BELOW) IF THE MODELS PAN OUT. OVERNIGHT, A 500 MB SHORTWAVE PUSHES THROUGH THE FORECAST AREA, BUT THE MODELS SUGGEST THAT ONLY THE MOISTURE IN THE 700-500 MB LAYER WOULD INCREASE, IF ANY AT ALL. SO WILL EXPECT THAT THE NIGHT WOULD REMAIN DRY. MAY IDEAS IS THAT THE SKY REMAINS CLEAR TO PARTLY CLOUDY, SO TEMPERATURES LOOK TO BE IN THE LOWER TO MID 30S, SO ANOTHER FROST NIGHT? PUT PATCHY IN FOR THE INLAND AREAS, AND LEFT THE LAKE SHORES FROST FREE WHERE THE AIR TEMPERATURE IS EXPECTED TO BE A LITTLE WARMER. && .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 319 AM EDT MON MAY 18 2015 EXTENDED (THURSDAY THROUGH SUNDAY)...WITH THE 500 MB TROUGH THAT PARKS ITSELF OVER THE NEW ENGLAND STARTING TUESDAY AND HANGS THERE THROUGH FRIDAY. FRIDAY, THE LOW BEGINS TO MOVE OUT ALLOWING THE 500 MB RIDGE TO BUILD IN THE UPPER GREAT LAKES. SO WHAT DOES THIS MEAN FOR THE LONG TERM? SFC HIGH PRESSURE WILL CAMP OUT IN THE UPPER GREAT LAKES THROUGH THE WEEK, KEEPING THE AREA DRY THROUGH SATURDAY NIGHT, AND THE 500 MB PATTERN WILL KEEP THE HIGH TEMPERATURES AROUND OR BELOW NORMAL THROUGH THE WEEK WHEN THE NORMAL HIGH TEMPERATURES IN GAYLORD AND SAULT STE. MARIE ARE IN THE UPPER 60S. SUNDAY, THE MODELS BEGIN TO KEY IN ON THE NEXT 500 MB LOW THAT MOVES OUT OF THE CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS, PRODUCING SHOWERS AND POSSIBLY THUNDERSTORMS AS THE WARM FRONT PUSHES UP THROUGH THE STATE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY) ISSUED AT 700 AM EDT MON MAY 18 2015 VFR CONDITIONS ARE EXPECTED AT ALL NRN LWR MICHIGAN TAF SITES THRU TODAY AS THE DRY SLOT (ASSOCIATED WITH DEEP LOW PRESSURE JUST WEST OF MICHIGAN) REMAINS OVERHEAD. A LARGE AREA OF LOW LEVEL MOISTURE WILL WRAP BACK INTO NRN MICHIGAN TONIGHT AS THE SURFACE LOW RIDES EAST THRU MICHIGAN AND THEN EXITS INTO QUEBEC. SW SURFACE WINDS AROUND 10 KTS WILL SHIFT TO THE W/NW THIS EVENING. && .MARINE... ISSUED AT 319 AM EDT MON MAY 18 2015 WINDS AND WAVES WILL APPROACH SCA CRITERIA TODAY AND ESPECIALLY TONIGHT AS CAA DEVELOPS ON THE WAKE OF A DEPARTING LOW. AT THIS POINT...EXPECT CONDITIONS SHOULD REMAIN UNDER CRITERIA...SO WILL NOT ISSUE A SCA AT THIS TIME. STRONGER NW WINDS WILL LIKELY DEVELOP ON TUESDAY AS CAA STRENGTHENS BEHIND THE DEPARTING LOW. AREAS OF FOG AND LOW STRATUS WILL CONTINUE TO IMPACT OUR NEARSHORE AREAS THRU THIS MORNING BEFORE MIXING OUT THIS AFTERNOON. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JAZ NEAR TERM...MLR SHORT TERM...JSL LONG TERM...JSL AVIATION...MLR MARINE...MLR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
751 AM EDT MON MAY 18 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 508 AM EDT MON MAY 18 2015 WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING HRS. TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR (FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT. BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z TUE. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON MAY 18 2015 TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE 17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING. 850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT 12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH DIMINISHES SIGNIFICANTLY. EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF THE INTERIOR W HALF OF UPPER MI/. EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND 0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY /ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/. DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 743 AM EDT MON MAY 18 2015 WRAPAROUND MOISTURE BEGINNING TO ARRIVE AT THE WRN TAF SITES WILL PRODUCE SOME SCT RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS. DRY AIR WILL KEEP KSAW VFR UNTIL LATE MORNING WHEN MOISTURE AND BANK OF STRATU MOVES IN FROM THE SW...THEN COULD SEE A PERIOD OF MVFR CIGS. PUSH OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH POSSIBLE IFR CONDITIONS DEVELOPING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT MON MAY 18 2015 LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING AS COLDER AIR ARRIVES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...VOSS MARINE...VOSS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
757 AM EDT MON MAY 18 2015 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING WITH STACKED SURFACE AND UPPER LEVEL LOW OVER THE MINNESOTA ARROWHEAD CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE GREAT LAKES. DEWPOINTS RISING INTO THE MID 60S ACROSS WESTERN NEW YORK AS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES /NEAR MAX ON MID MAY SOUNDING CLIMO/ RUNNING FROM NORTH OF GEORGIAN BAY TO LAKE ERIE. PLENTY OF MOISTURE TO BE FOUND SO FOCUS FOR TIMING OF SHOWER AND THUNDERSTORM ACTIVITY TODAY WILL BE ON ANY SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS THE EASTERN GREAT LAKES. A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS. TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A SECOND ROUND OF SHOWER/TSTM ACTIVITY. TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING MAXIMUM. OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH. TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW TO MID 50S. BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE 40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... IT WILL BE A DRY DAY ON THURSDAY WITH PASSING HIGH CLOUDS AS THE REGION WILL REMAIN UNDERNEATH THE FLATTENED BASE OF A DEEP UPPER LEVEL LOW CENTERED NEAR JAMES BAY. THE UPPER LEVEL FLOW WILL AMPLIFY ONCE MORE ACROSS THE AREA ON FRIDAY AS A JET MAX DROPS INTO THE BASE OF THE TROUGH OVER NORTHEASTERN ONTARIO. THIS WILL HELP PUSH ANOTHER WEAK COLD FRONT ACROSS UPSTATE AND WESTERN NEW YORK ON FRIDAY...POTENTIALLY TRIGGERING A SHOWER OR TWO ACROSS THE NORTH COUNTRY. HOWEVER...A LACK OF MOISTURE WILL ONCE AGAIN LIMIT POPS TO A SLIGHT CHANCE AT BEST. AN EVEN MORE BENIGN PATTERN TAKES SHAPE FOR THE COMING WEEKEND AS SURFACE HIGH PRESSURE TRACKS OVER THE LOWER GREAT LAKES. THERE WILL BE PLENTY OF SUNSHINE TO BE HAD FRIDAY AND SATURDAY AS THE HIGH MOVES OVERHEAD BEFORE MOVING OFF THE EAST COAST SUNDAY. AS THE HIGH MOVES OFF THE EAST COAST...LOOK FOR RETURN FLOW TO SET UP ACROSS THE LOWER GREAT LAKES THAT WILL SIGNAL A RETURN TO WARMER CONDITIONS SUNDAY WITH UNSETTLED WEATHER LIKELY TO FOLLOW BY MONDAY AS A WARM FRONT LIFTS NORTH ACROSS THE GREAT LAKES. REGARDING TEMPERATURES...READINGS WILL RUN IN THE 60S ON THURSDAY. WHILE CERTAINLY WARMER THAN THE CHILLY 50S EXPECTED WEDNESDAY...THE LOWER GREAT LAKES REGION WILL REMAIN CLOSE ENOUGH TO THE AFOREMENTIONED UPPER LEVEL LOW TO KEEP TEMPERATURES A FEW DEGREES BELOW NORMAL. INDEED THE PASSAGE OF THE WEAK COOL FRONT FRIDAY WILL KNOCK TEMPS BACK A COUPLE OF DEGREES. WITH HIGH PRESSURE MOVING BUILDING FRIDAY NIGHT AND COOL/DRY AIR IN PLACE...WE SHOULD SEE A CHILLY NIGHT WITH LOWS IN THE LOW/MID 40S...WITH UPPER 30S IN THE SOUTHERN TIER AND NORTH COUNTRY. THIS TIME WINDS MAY BE LIGHT ENOUGH TO POTENTIALLY ALLOW FOR FROST ACROSS THE SHELTERED AREAS OF THE NORTH COUNTRY AND THE SOUTHERN TIER. THEREAFTER...TEMPERATURES SHOULD GRADUALLY REBOUND THROUGH THE WEEKEND AS THE HIGH DRIFTS EAST OF THE REGION AND RETURN FLOW TAKES HOLD WITH WIDESPREAD 70S EXPECTED ONCE AGAIN BY SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS FOR KJHW/KROC/KART DURING THE LATE MORNING AND AFTERNOON AS A PRE- FRONTAL TROUGH CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE ERIE SHOULD KEEP KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL DEVELOP FROM THE SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND SYRACUSE. STORM ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH MAINLY DRY CONDITIONS EXPECTED TONIGHT. SOME LOW CLOUDS/FOG MAY BRING IFR TO KJHW LATE TONIGHT ESPECIALLY IF HEAVY RAIN FALLS ACROSS THE SOUTHERN TIER. OUTLOOK... TUESDAY THROUGH FRIDAY...VFR. && .MARINE... LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS AND WAVES. A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST OF THE WEEK WITH LOW WIND AND WAVE ACTION. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040- 041. && $$ SYNOPSIS...SMITH NEAR TERM...SMITH SHORT TERM...WOOD LONG TERM...WOOD AVIATION...SMITH MARINE...SMITH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1108 AM EDT MON MAY 18 2015 .SYNOPSIS... WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON. && .NEAR TERM /THROUGH TONIGHT/... NO UPDATES TO THE NEAR TERM OTHER THAN TO TWEAK POPS BASED ON CURRENT TRENDS. PREVIOUS DISCUSSION BELOW... LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING. LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA. MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT OF SHOWERS AND STORMS TODAY. LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND POOR DRAINAGE AREAS. WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE THE THREAT OF SHOWERS AND STORMS. CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST. RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE FRONT STARTING TUESDAY NIGHT. DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST GIVING ZONAL FLOW FOR THE OHIO VALLEY. WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /THURSDAY THROUGH SUNDAY/... NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY. WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... 12Z MONDAY THRU 12Z TUESDAY... CONDITIONS HAVE IMPROVED SINCE 09Z...WITH MOST LOCATIONS MVFR OR BETTER. HOWEVER...ISOLATED IFR CONDITIONS MAY STILL BE OCCURRING ALONG RIVER VALLEYS. LATEST RADAR SHOWS ISOLATED SHOWERS HAVE BEGUN TO DEVELOP ACROSS PORTIONS OF SOUTHEAST OHIO AND NORTHEAST KENTUCKY. THESE SHOWER WERE DEVELOPING IN RESPONSE TO AN UPPER LEVEL DISTURBANCE. EXPECT THESE SHOWERS WILL CONTINUE TO SPREAD ACROSS THE REMAINDER OF THE STATE...AS THE DISTURBANCE MOVES NORTHEAST.. ADDITIONAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA TODAY... WHICH WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS... ESPECIALLY FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST LOCATIONS WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS ARE POSSIBLE NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO POSSIBLE NEAR THE STRONGER STORMS. THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED STORMS WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H M M M M H H HTS CONSISTENCY H H H M M M H H M H H H BKW CONSISTENCY H H H H H H H H M M M M EKN CONSISTENCY L M M H M H H H M M M M PKB CONSISTENCY H H H H H H H H M H H H CKB CONSISTENCY H H H H H H H H M M M M AFTER 12Z TUESDAY... BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE IN LOW CLOUDS TUE MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/ARJ NEAR TERM...JSH/KMC SHORT TERM...FB LONG TERM...FB AVIATION...JSH
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
901 AM EDT MON MAY 18 2015 .SYNOPSIS... A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... REMOVED ALL POPS FOR REMAINDER OF MORNING. BUMPED UP TEMPS ALONG THE EASTERN ERIE LAKESHORE DUE TO UPSLOPE FLOW. REMAINDER OF FORECAST LOOKS REASONABLE. ORIGINAL DISCUSSION... WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES WARMER. PREVIOUS DISCUSSION... NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE. HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING. WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE EAST AND 80 TO 84 IN THE WEST. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE INTO THE REGION. HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN. NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN COME TO SOME KIND OF CONSENSUS. UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT. THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH. OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S. YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY FROST THROUGH THE PERIOD AT THIS TIME. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND. SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST. MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION. FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z. WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE FORECAST PERIOD REMAIN MVFR. .OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA TUESDAY NIGHT. && .MARINE... LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...DJB/LOMBARDY SHORT TERM...LOMBARDY LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
727 AM EDT MON MAY 18 2015 .SYNOPSIS... A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES WARMER. PREVIOUS DISCUSSION... NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE. HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING. WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE EAST AND 80 TO 84 IN THE WEST. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE INTO THE REGION. HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN. NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN COME TO SOME KIND OF CONSENSUS. UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT. THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH. OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S. YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY FROST THROUGH THE PERIOD AT THIS TIME. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND. SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST. MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION. FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z. WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE FORECAST PERIOD REMAIN MVFR. .OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA TUESDAY NIGHT. && .MARINE... LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY SHORT TERM...LOMBARDY LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
645 AM EDT MON MAY 18 2015 .SYNOPSIS... WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON. && .NEAR TERM /THROUGH TONIGHT/... LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING. LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA. MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT OF SHOWERS AND STORMS TODAY. LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND POOR DRAINAGE AREAS. WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE THE THREAT OF SHOWERS AND STORMS. CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST. RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE FRONT STARTING TUESDAY NIGHT. DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST GIVING ZONAL FLOW FOR THE OHIO VALLEY. WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /THURSDAY THROUGH SUNDAY/... NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY. WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... 12Z MONDAY THRU 12Z TUESDAY... CONDITIONS HAVE IMPROVED SINCE 09Z...WITH MOST LOCATIONS MVFR OR BETTER. HOWEVER...ISOLATED IFR CONDITIONS MAY STILL BE OCCURRING ALONG RIVER VALLEYS. LATEST RADAR SHOWS ISOLATED SHOWERS HAVE BEGUN TO DEVELOP ACROSS PORTIONS OF SOUTHEAST OHIO AND NORTHEAST KENTUCKY. THESE SHOWER WERE DEVELOPING IN RESPONSE TO AN UPPER LEVEL DISTURBANCE. EXPECT THESE SHOWERS WILL CONTINUE TO SPREAD ACROSS THE REMAINDER OF THE STATE...AS THE DISTURBANCE MOVES NORTHEAST.. ADDITIONAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA TODAY... WHICH WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS... ESPECIALLY FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST LOCATIONS WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS ARE POSSIBLE NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO POSSIBLE NEAR THE STRONGER STORMS. THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED STORMS WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY L H H H H H H H H M M M HTS CONSISTENCY H H H H H H M M M H H M BKW CONSISTENCY H H H H H H H H H H H M EKN CONSISTENCY L M L L H H H M H H H M PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H M H H H H H H M AFTER 12Z TUESDAY... BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE IN LOW CLOUDS TUE MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/ARJ NEAR TERM...JSH SHORT TERM...FB LONG TERM...FB AVIATION...JSH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
635 AM EDT MON MAY 18 2015 .SYNOPSIS... A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES WARMER. PREVIOUS DISCUSSION... NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE. HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING. WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE EAST AND 80 TO 84 IN THE WEST. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE INTO THE REGION. HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN. NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN COME TO SOME KIND OF CONSENSUS. UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT. THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH. OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S. YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY FROST THROUGH THE PERIOD AT THIS TIME. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND. SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST. MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... CONDITIONS VFR ACROSS NRN OHIO AND NWRN PA AT 05Z. AIRMASS QUITE MOIST BUT UPPER RIDGE JUST EAST OF THE AREA MOSTLY KEEPING A LID ON CONVECTION. GUIDANCE SUGGESTS OVERNIGHT AND INTO THE EARLY MORNING HOURS CIGS AND VISIBILITIES SHOULD GO DOWN TO IFR IN STRATUS AND FOG. AM IN AGREEMENT WITH MVFR VISIBILITIES IN A MORNING FOG/MIST HAVE OPTED TO REMAIN MORE CONSERVATIVE THAN GUIDANCE WHICH MAY BE TOO PESSIMISTIC AS STRATUS THAT HAS DEVELOPED HAS BEEN AT 5 TO 7 KFT. TIME WILL TELL. AS FOR MONDAY GIVEN MOISTURE AND THE APPROACHING COLD FRONT FROM THE WEST WILL CONTINUE WITH VCTS FOR THE AFTERNOON ACROSS THE AREA IN DIURNAL CONVECTION. COULD ALSO HAVE ANOTHER LINE APPROACHING WESTERN TERMINALS TOWARD THE END OF THE PERIOD WITH THE FRONT. .OUTLOOK...NON VFR AT TIMES IN SCATTERED SHOWERS OR THUNDERSTORMS TONIGHT. NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA TUESDAY AFTERNOON/EVENING. && .MARINE... LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY SHORT TERM...LOMBARDY LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
620 AM CDT MON MAY 18 2015 .AVIATION... VFR CONDITIONS EXPECTED DURING THE DAY...BUT WILL DETERIORATE TO MVFR DECKS AND VIS COURTESY OF INCREASING CHANCES OF THUNDERSTORMS THIS EVENING THROUGH TONIGHT. HAVE INSERTING A PREVAILING TSRA AT ALL THREE TAF SITES...COMMENCING THIS EVENING AT KLBB AND KPVW...AND MORE SO BY TONIGHT AT KCDS. RAINFALL COULD BECOME HEAVY AT TIMES. OTHERWISE...LIGHT SOUTHWEST WINDS EARLY THIS MORNING WILL BACK TO THE SOUTH SOUTHEAST THIS AFTERNOON AT 10-15 KTS. && .PREV DISCUSSION... /ISSUED 340 AM CDT MON MAY 18 2015/ SHORT TERM... THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY AS LATE THIS AFTN. THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS. COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES INDEED OCCUR. ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00- 1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS. WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40 KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY THREATS/. A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND 80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S. LONG TERM... THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL BEGIN TO THIN FROM WEST TO EAST. WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM. THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD AND THEN RETREATS FRIDAY AND SATURDAY. TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE CAA ASSOCIATED WITH THE FROPA. ALDRICH && .PRELIMINARY POINT TEMPS/POPS... FRIONA 78 55 71 49 / 10 80 90 20 TULIA 79 57 69 51 / 10 80 90 40 PLAINVIEW 79 58 70 53 / 10 80 90 40 LEVELLAND 83 60 74 56 / 20 80 90 30 LUBBOCK 83 61 73 57 / 10 80 90 40 DENVER CITY 82 61 76 60 / 30 80 80 20 BROWNFIELD 84 61 74 59 / 20 80 90 30 CHILDRESS 86 63 71 60 / 10 60 90 60 SPUR 84 63 73 61 / 10 70 90 50 ASPERMONT 87 66 75 64 / 10 70 90 50 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 29
AREA FORECAST DISCUSSION
NWS RENO NV
300 PM PDT MON MAY 18 2015 .SYNOPSIS... LOW PRESSURE ALOFT WILL REMAIN OVER CALIFORNIA AND NEVADA THROUGH THE END OF THE WORK WEEK, BRINGING BELOW AVERAGE TEMPERATURES AND ROUNDS OF SHOWERS AND THUNDERSTORMS, MAINLY IN THE AFTERNOONS AND EVENINGS. PRECIPITATION CHANCES DECREASE OVER THE MEMORIAL DAY WEEKEND ALTHOUGH A FEW SHOWERS AND THUNDERSTORMS WILL STILL BE POSSIBLE. && .SHORT TERM... A TROUGH OF LOW PRESSURE REMAINS OVER THE WEST. AN UPPER DISTURBANCE OVER SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA IS ROTATING AROUND THE TROUGH, BRINGING INCREASED DIVERGENCE ALOFT AND HELPING TO INITIATE SHOWERS AND THUNDERSTORMS OVER SOUTHERN AND EASTERN NEVADA. FOR NORTHEAST CALIFORNIA AND WESTERN NEVADA, ACTIVITY IS RESTRICTED EARLY THIS AFTERNOON WITH THE BEST FORCING SOUTH AND EAST OF THE AREA. HOWEVER, SCATTERED SHOWERS SHOULD STILL DEVELOP GIVEN THE MOIST AND WEAKLY UNSTABLE ATMOSPHERE, ESPECIALLY FOR EASTERN CALIFORNIA AND FAR WESTERN NEVADA WHERE THE HRRR AND NAM SHOW A LIGHT WESTERLY FLOW OFF THE SIERRA (TO AID LOW LEVEL CONVERGENCE AND UPWARD MOTION) INTO THE EVENING. AS FAR AS THUNDERSTORMS, LOW FREEZING LEVELS AND WEAK INSTABILITY MAKE IT HARD TO RULE OUT BRIEF, ISOLATED CELLS. ANY STORMS THIS EVENING WILL BE WEAK WITH THE MAIN THREAT BEING LIGHTNING AND LARGE QUANTITIES OF SMALL, SOFT HAIL (GRAUPEL TECHNICALLY). LATE TONIGHT, THE HRRR AND LESS-SO THE GFS AND NAM ARE INDICATING WRAP-AROUND PRECIPITATION OVER NORTHEAST CALIFORNIA AND NORTHWEST NEVADA AS THE UPPER LOW ADVANCES INTO EASTERN NEVADA. WITH THIS IN MIND, I HAVE LEFT IN SCATTERED SHOWERS NORTH OF RENO AND FALLON WITH ISOLATED COVERAGE ELSEWHERE. TUESDAY, THE REGION IS BETWEEN UPPER WAVES. HOWEVER, MOISTURE REMAINS IN PLACE AND BETTER HEATING IS POSSIBLE WITH LITTLE UPPER FORCING ALLOWING FOR LESS/THINNER CLOUD COVER IN THE MORNING. THIS SHOULD FACILITATE SCATTERED SHOWERS IN THE AFTERNOON AND EVENING, WITH A LOW CHANCE FOR THUNDERSTORMS. WEDNESDAY, THE BEST UPPER FORCING OF THE SHORT TERM IS EXPECTED AS ANOTHER DISTURBANCE RELOADS THE SOUTHWEST CONUS TROUGH. THE DISTURBANCE IS EXPECTED TO MOVE FROM SOUTH TO NORTH THROUGH CALIFORNIA WITH THE BEST FORCING IN THE AFTERNOON AND EVENING. WITH THIS IN MIND, I HAVE BUMPED POP A BIT MORE OVER MUCH OF FAR WESTERN NEVADA AND EASTERN CALIFORNIA WITH NUMEROUS SHOWERS EXPECTED BY AFTERNOON. WITH THE FORCING, I WOULD EXPECTED AT LEAST ISOLATED THUNDERSTORMS WITH HIGHER COVERAGE POSSIBLE IF WE CAN GET DECENT MORNING HEATING (CLEARER SKIES). SNYDER .LONG TERM...THURSDAY THROUGH MONDAY... BY THURSDAY AN AREA OF LOW PRESSURE WILL AGAIN BE ALONG THE CENTRAL CALIFORNIA COAST. THIS WILL CONTINUE TO BRING WIDESPREAD CHANCES OF PRECIPITATION, ISOLATED THUNDERSTORMS, AND BELOW AVERAGE DAYTIME TEMPERATURES. THURSDAY CURRENTLY LOOKS TO BE THE WETTEST DAY WITH MOISTURE WRAPPING AROUND THE LOW PRESSURE AND BANKING AGAINST THE SIERRA FROM THE EAST. RELATIVELY DEEP MOISTURE AND UPSLOPE FLOW COULD ALLOW SOME AREAS TO PICK UP ANOTHER ROUND OF SIGNIFICANT PRECIPITATION, ESPECIALLY IN THE CENTRAL SIERRA. BY FRIDAY THE LOW PRESSURE WILL MOVE INTO SOUTHERN NEVADA BRINGING NORTHERLY FLOW TO THE AREA. THIS WILL DECREASE THE CHANCE OF SIGNIFICANT QPF IN THE SIERRA, BUT WILL STILL ALLOW WIDESPREAD PRECIPITATION TO WESTERN NEVADA AND THE SIERRA. FOR THE HOLIDAY WEEKEND... CHANCES FOR THUNDERSTORMS WILL BE ON THE DECREASE BY THE HOLIDAY WEEKEND AS THE LOW PRESSURE MOVES INTO THE ROCKIES, BUT WITH SOME RESIDUAL MOISTURE AND INCREASING TEMPERATURES THERE IS STILL A SLIGHT CHANCE OF THUNDERSTORM ACTIVITY IN SIERRA AND WESTERN NEVADA THROUGH THE WEEKEND. SIGNIFICANT MODEL DISCREPANCIES EXIST BY THE WEEKEND SO FORECAST CONFIDENCE IS CURRENTLY LOW ON THE BEST AREA FOR THUNDERSTORM CHANCES. EXPECT A WARMING TREND THROUGH THE WEEKEND WITH DAYTIME TEMPERATURES RIGHT AROUND SEASONAL AVERAGES WITH MID 70`S IN WESTERN NEVADA AND MID 60`S IN THE SIERRA. BY MONDAY WESTERN NEVADA VALLEYS COULD HIT 80 WITH SIERRA VALLEYS REACHING 70. TOLBY && .AVIATION... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED THROUGHOUT THE SIERRA AND WESTERN NEVADA THROUGH THIS EVENING. LOW CLOUD DECKS AND RAIN SHOWERS WILL CREATE SOME MOUNTAIN OBSCURATION IN THE SIERRA. GENERALLY LIGHT WEST WINDS WITH THE CHANCE OF GUSTS TO AROUND 30 KTS NEAR THUNDERSTORMS. TOLBY && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS TAUNTON MA
318 PM EDT MON MAY 18 2015 .SYNOPSIS... MARITIME HIGH PRESSURE BUILDS OVER NEW ENGLAND BRINGING COOLER MARINE AIR TODAY...BUT IT SILL WILL BE A RATHER MILD DAY ACROSS THE INTERIOR. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS TO THE REGION TONIGHT INTO TUE WITH A LOW POTENTIAL FOR AN ISOLATED THUNDERSTORM. WIDELY SCATTERED SHOWERS ARE POSSIBLE WEDNESDAY...FRIDAY...AND MONDAY. BUT IN GENERAL DRY WEATHER AND SEASONABLE TEMPS ARE EXPECTED FROM MID WEEK THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 200 PM UPDATE... SKIES HAVE BECOME MOSTLY SUNNY ACROSS THE VAST MAJORITY OF THE REGION AT MID AFTERNOON. TEMPS HAVE CLIMBED INTO THE 70S ACROSS THE INTERIOR...60S JUST INLAND FROM THE COAST...AND BETWEEN 55 AND 60 ALONG THE IMMEDIATE COAST. TEMPS MAY CLIMB ANOTHER FEW DEGREES ESPECIALLY ACROSS THE INTERIOR. HOWEVER...THE MAIN CONCERN ARE THE LOW CLOUDS AND AREAS OF FOG JUST MOVING ONTO THE OUTER-CAPE. MOST OF THE GUIDANCE IS NOT HANDLING THIS WELL...BUT THE HRRR AND TO SOME DEGREE THE RAP SHOWS THESE LOW CLOUDS AND FOG BACKING INTO EASTERN MAY LATE THIS AFTERNOON/EARLY THIS EVENING. CONFIDENCE IS LOW...BUT GIVEN EASTERLY FLOW LEANING TOWARDS THAT HAPPENING. WILL CONTINUE TO MONITOR. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... LOW PRESSURE MOVES INTO QUEBEC BRINGING A COLD FRONT TOWARDS SOUTHERN NEW ENGLAND. MUCH OF TONIGHT SHOULD BE DRY WITH INCREASING CLOUDS. SHOWERS SHOULD HOLD OFF UNTIL WELL AFTER MIDNIGHT. TEMPERATURES OVERNIGHT WILL BE A COUPLE OF DEGREES COOLER THAN THIS MORNINGS TEMPS WITH THE CONTINUED EASTERLY FLOW AND HIGH PRESSURE EAST OF SOUTHERN NEW ENGLAND. SHOWERS WILL BEGIN WELL AFTER MIDNIGHT AS THE FRONT APPROACHES SOUTHERN NEW ENGLAND. INSTABILITY INCREASES AS DAYBREAK APPROACHES WITH INCREASING MID LEVEL LAPSE RATES AND K INDICES ABOVE 30. SHOWALTER INDICES FALL BELOW 0 IN A FEW LOCATIONS BUT THIS IS NOT WIDESPREAD. WITH THE INSTABILITY IN PLACE...EXPECT WE WILL SEE A FEW THUNDERSTORMS BUT BELIEVE THE MAIN THREAT WILL BE FROM AREAS OF HEAVY RAINFALL. PWATS OF 1.5 TO 1.75 INCHES ARE ABOUT 2 STD ABOVE NORMAL FOR MID MAY. IN ADDITION...850MB WINDS ARE ONLY 20-25KTS. NOT ENOUGH TO MOVE STORMS ALONG QUICKLY. DON/T BELIEVE THERE WILL BE WIDESPREAD FLOODING BUT DEPENDING ON THE TRACKS OF STORMS COULD SEE SOME POOR DRAINAGE FLOODING WHERE STORMS TRAIN. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... BIG PICTURE... THE PATTERN EVOLVES THROUGH THE WEEKEND WITH FLAT FLOW IN THE EASTERN USA GIVING WAY TO A DIGGING TROUGH LATE WEEK. THE TROUGH RELAXS A LITTLE OVER THE WEEKEND. TWO SHORTWAVES MOVE THROUGH THE FLOW...ONE ON WEDNESDAY AND THE SECOND ON FRIDAY. CONTOUR HEIGHTS LOWER BELOW SEASONAL NORMS WEDNESDAY-THURSDAY...THEN RETURN TO NEAR SEASONABLE LEVELS OVER THE WEEKEND. JET PATTERN STARTS WITH NORTHERN AND SOUTHERN STREAMS...BUT THESE MERGE LATER IN THE WEEK IN THE EASTERN USA AS THE UPPER TROUGH DIGS. THE DAILIES... WEDNESDAY... COLD FRONT MOVES WELL OFFSHORE WEDNESDAY WITH COOLER DRIER AIR MOVING INTO NEW ENGLAND. UPPER SHORTWAVE AND COLDER TEMPS/MOISTURE ALOFT WILL GENERATE DIURNAL CU ESPECIALLY ALONG AND NORTH OF THE MASS PIKE. THE AIRMASS IS PROBABLY TOO DRY BELOW 5000 FEET FOR SCATTERED AFTERNOON SHOWERS. MIXING SHOULD REACH 850 MB WHICH WHERE TEMPS OF 1-4C SHOULD SUPPORT MAX SFC TEMPS IN THE 60S. TEMPS COULD REACH 70 IN THE SOUTH ESPECIALLY RI/SOUTHEAST MASS WHERE TEMPS ALOFT MAY BE A LITTLE MILDER OR MIXING A LITTLE DEEPER. WINDS IN THE MIXED LAYER WILL BE 20-25 KNOTS...SO WIND GUSTS SHOULD APPROACH THOSE SPEEDS. WINDS DIMINISH WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS IN. WITH DEW POINTS IN THE 30S...TEMPS SHOULD FALL TO THE 30S IN THE COLDER SPOTS...WITH 40S SOUTH AND EAST. THURSDAY...AFTER THE CHILLY START HIGH PRESSURE SHOULD PROVIDE A FAIR DRY DAY. MIXING SHOULD REACH 800 MB WHERE TEMPS 0-2C SUPPORT MAX SFC TEMPS 65 TO 70. FRIDAY-SATURDAY-SUNDAY... UPPER SHORTWAVE AND CORRESPONDING SURFACE COLD FRONT SWEEP THROUGH ON FRIDAY. THIS MAY CAUSE WIDELY SCATTERED SHOWERS BUT PRECIP WATER VALUES AT OR BELOW 0.5 INCHES SUGGEST A DRY ENVIRONMENT TO OVERCOME. WE USED LOW-END SLIGHT CHANCE POPS FOR THIS PASSAGE. HIGH PRESSURE THEN BUILDS EAST SATURDAY AND PROVIDES DRY WEATHER MUCH OF THE WEEKEND. SUNDAY NIGHT-MONDAY...A COLD FRONT DROPS SOUTH INTO NEW ENGLAND. MODEL CONSENSUS SUGGESTS A FEW SHOWERS MOVING THROUGH THE REGION DURING THIS PERIOD...BUT QUESTIONS ABOUT HOW FAR SOUTH THE FRONT PROGRESSES BEFORE STALLING. WE WILL CONTINUE TO INDICATE A CHANCE OF SHOWERS. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THIS AFTERNOON THROUGH TUESDAY NIGHT/... THIS AFTERNOON AND TONIGHT...LOW TO MODERATE CONFIDENCE. VFR CONDITIONS AT MID AFTERNOON WILL DETERIORATE TO LOW END MVFR/IFR WITH EVEN SOME LIFR CONDITIONS POSSIBLE TONIGHT...BUT TIMING HIGHLY UNCERTAIN. MODELS NOT PICKING UP ON A DECK OF LOW CLOUDS/FOG SITTING OFF CAPE COD WHICH MAY BACK INTO EASTERN MA LATER THIS AFTERNOON/EVENING. OTHER AREAS OF LOW CLOUDS AND FOG ARE EXPECTED TO DEVELOP ACROSS THE REST OF THE REGION...BUT TIMING UNCERTAIN. A CLUSTER OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS WILL MAY WORK INTO OUR WESTERN ZONES TOWARD DAYBREAK. TUESDAY AND TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE. A CLUSTER OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE REGION TUE MORNING INTO EARLY AFTERNOON...BEFORE EXITING THE REGION. LOW END MVFR TO IFR CONDITIONS EXPECTED FOR AT LEAST THE MORNING. TEMPORARY IMPROVEMENT TO VFR MAY OCCUR ESPECIALLY ACROSS THE INTERIOR TUE AFTERNOON. A FEW STRONG THUNDERSTORMS MAY WORK INTO WESTERN MA/NORTHERN CT LATE TUE AFTERNOON/EVENING. ISOLATED STRONG WIND GUSTS/HAIL WILL BE POSSIBLE WITH THIS ACTIVITY. EXPECT THE ACTIVITY TO WEAKEN AS IT MOVES INTO EASTERN MA/RI. CONDITIONS THEN IMPROVE TO VFR FROM WEST TO EAST. KBOS TERMINAL...LOW CONFIDENCE. WATCHING A BANK OF LOW CLOUDS/FOG THAT MAY MOVE INTO THE TERMINAL LATE THIS AFTERNOON/EARLY EVENING BUT LOW CONFIDENCE. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOW END MVFR TO IFR EXPECTED TO DEVELOP TONIGHT BUT TIMING UNCERTAIN. OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE. VFR THROUGH THE PERIOD. NORTHWEST WINDS WILL GUST TO 25 KNOTS WEDNESDAY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE OVER THE WATERS. EASTERLY WINDS 5 TO 10 KTS WILL SHIFT TO THE SOUTH TONIGHT AND INCREASE TO 10 TO 15 KTS WITH GUSTS TO 20 KTS TUESDAY. OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE. WEDNESDAY... INCREASING NORTHWEST WINDS DURING THE DAY. THIS MAY BRING A PERIOD OF GUSTS TO 25 KNOTS DURING THE AFTERNOON. SEAS SHOULD REMAIN BELOW 5 FEET. WILL MONITOR FOR POTENTIAL SMALL CRAFT HEADLINES DUE TO AFTERNOON WIND GUSTS. THURSDAY-FRIDAY... HIGH PRESSURE MOVES OVERHEAD THURSDAY. A WEAK COLD FRONT PASSES THROUGH ON FRIDAY. WINDS AND SEAS SHOULD REMAIN BELOW SMALL CRAFT THRESHOLDS. FRIDAY NIGHT-SATURDAY... NORTHWEST WINDS BEHIND THE COLD FRONT WILL INCREASE AND BRING GUSTS TO 25 KNOTS ACROSS THE WATERS. THIS MAY BRIEFLY BRING SEAS UP TO 5 FEET. A SMALL CRAFT ADVISORY MAY BE NEEDED. && .FIRE WEATHER... WEDNESDAY...COOLER DRIER AIR MOVES IN. THE FORECAST HAS STAYED CLOSE TO MODEL CONSENSUS WHICH BRINGS DEW POINTS DOWN INTO THE 30S WITH RESULTING MINIMUM RELATIVE HUMIDITY PERCENTAGES IN THE 30S. THERE IS SOME CONCERN THAT THIS DATA IS MISSING THE PRESENCE OF DRIER AIR AT 5000 FEET/850 MB...WHERE DEW POINTS ARE FORECAST AT 26-30F DURING THE AFTERNOON. DAYTIME MIXING OF THIS AIRMASS MAY LOWER SURFACE DEW POINTS INTO THE UPPER 20S AND CREATE MIN RH VALUES OF 27-31 PERCENT. ALONG WITH THIS WILL BE EXPECTED WIND GUSTS NEAR 25 KNOTS. SO THE WEATHER PORTION OF THE FIRE WEATHER EQUATION IS INCHING TOWARD HIGHER CONCERN AND WILL NEED TO BE MONITORED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...WTB/RLG NEAR TERM...FRANK SHORT TERM...RLG LONG TERM...WTB AVIATION...WTB/FRANK MARINE...WTB/RLG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
200 PM EDT MON MAY 18 2015 .SYNOPSIS... MARITIME HIGH PRESSURE BUILDS OVER NEW ENGLAND BRINGING COOLER MARINE AIR TODAY...BUT IT SILL WILL BE A RATHER MILD DAY ACROSS THE INTERIOR. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS TO THE REGION TONIGHT INTO TUE WITH A LOW POTENTIAL FOR AN ISOLATED THUNDERSTORM. DRY WEATHER AND SEASONABLE TEMPS WILL FOLLOW FOR MID WEEK LASTING THROUGH NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 200 PM UPDATE... SKIES HAVE BECOME MOSTLY SUNNY ACROSS THE VAST MAJORITY OF THE REGION AT MID AFTERNOON. TEMPS HAVE CLIMBED INTO THE 70S ACROSS THE INTERIOR...60S JUST INLAND FROM THE COAST...AND BETWEEN 55 AND 60 ALONG THE IMMEDIATE COAST. TEMPS MAY CLIMB ANOTHER FEW DEGREES ESPECIALLY ACROSS THE INTERIOR. HOWEVER...THE MAIN CONCERN ARE THE LOW CLOUDS AND AREAS OF FOG JUST MOVING ONTO THE OUTER-CAPE. MOST OF THE GUIDANCE IS NOT HANDLING THIS WELL...BUT THE HRRR AND TO SOME DEGREE THE RAP SHOWS THESE LOW CLOUDS AND FOG BACKING INTO EASTERN MAY LATE THIS AFTERNOON/EARLY THIS EVENING. CONFIDENCE IS LOW...BUT GIVEN EASTERLY FLOW LEANING TOWARDS THAT HAPPENING. WILL CONTINUE TO MONITOR. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... LOW PRESSURE MOVES INTO QUEBEC BRINGING A COLD FRONT TOWARDS SOUTHERN NEW ENGLAND. MUCH OF TONIGHT SHOULD BE DRY WITH INCREASING CLOUDS. SHOWERS SHOULD HOLD OFF UNTIL WELL AFTER MIDNIGHT. TEMPERATURES OVERNIGHT WILL BE A COUPLE OF DEGREES COOLER THAN THIS MORNINGS TEMPS WITH THE CONTINUED EASTERLY FLOW AND HIGH PRESSURE EAST OF SOUTHERN NEW ENGLAND. SHOWERS WILL BEGIN WELL AFTER MIDNIGHT AS THE FRONT APPROACHES SOUTHERN NEW ENGLAND. INSTABILITY INCREASES AS DAYBREAK APPROACHES WITH INCREASING MID LEVEL LAPSE RATES AND K INDICES ABOVE 30. SHOWALTER INDICES FALL BELOW 0 IN A FEW LOCATIONS BUT THIS IS NOT WIDESPREAD. WITH THE INSTABILITY IN PLACE...EXPECT WE WILL SEE A FEW THUNDERSTORMS BUT BELIEVE THE MAIN THREAT WILL BE FROM AREAS OF HEAVY RAINFALL. PWATS OF 1.5 TO 1.75 INCHES ARE ABOUT 2 STD ABOVE NORMAL FOR MID MAY. IN ADDITION...850MB WINDS ARE ONLY 20-25KTS. NOT ENOUGH TO MOVE STORMS ALONG QUICKLY. DON/T BELIEVE THERE WILL BE WIDESPREAD FLOODING BUT DEPENDING ON THE TRACKS OF STORMS COULD SEE SOME POOR DRAINAGE FLOODING WHERE STORMS TRAIN. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * SCT SHOWERS AND AN ISOLD TSTM POSSIBLE TUE EVENING * DRY AND SEASONABLE CONDITIONS MID WEEK INTO NEXT WEEKEND WITH WARMING TEMPS NEXT SUNDAY OVERVIEW... MODELS REMAIN IN GOOD AGREEMENT ON LARGE SCALE FLOW PATTERN WITH MID LEVEL VORTEX SETTING UP ACROSS SE CANADA MID TO LATE WEEK WITH BROAD LONGWAVE TROF ACROSS THE GT LAKES AND NEW ENG. A FEW SHORTWAVES ROTATING THROUGH THE CYCLONIC FLOW WILL BRING A FEW FRONTS INTO THE REGION BUT MAINLY DRY AND SEASONABLE CONDITIONS AS POLAR JET WILL KEEP VERY WARM TEMPS SUPPRESSED TO THE SE US. NEXT WEEKEND...THE TROF BEGINS TO LIFT NE WITH RISING HEIGHTS AS RIDGE BUILDS OVER SE US. THIS WILL RESULT IN WARMING TEMPS TOWARD THE END OF THE WEEKEND. TUESDAY NIGHT... COLD FRONT WILL BE MOVING INTO W NEW ENG AROUND 00Z WED. AXIS OF MARGINAL SFC INSTABILITY WITH CAPES AROUND 500 J/KG WILL BE CONFINED TO W ZONES INVOF THE FRONT SO A FEW THUNDERSTORMS POSSIBLE ALONG THE BOUNDARY IN THE EVENING IN THE WEST. 0-6KM SHEAR AROUND 40 KT BUT INSTABILITY WILL BE A LIMITING FACTOR FOR SEVERE WEATHER. LOW PROB OF A STRONG TSTM IN W NEW ENG IN THE EVENING. OTHERWISE...EXPECT A FEW SHOWERS REST OF SNE IN THE EVENING UNTIL THE FROPA...THEN PARTIAL CLEARING OVERNIGHT BEHIND THE FRONT. WEDNESDAY... DRY POST-FRONTAL NW FLOW WILL PREVAIL AND IT WILL BE GUSTY AT TIMES WITH GUSTS 25-30 MPH. MID LEVEL SHORTWAVE WILL BE MOVING TO THE NORTH WITH MAIN IMPACT BEING SOME DIURNAL CU...ESPECIALLY N ZONES. HIGHS WILL BE MOSTLY IN THE 60S...WITH A FEW 70 DEGREE READINGS IN RI/SE MA. THURSDAY THROUGH SUNDAY... MODELS BRING A WEAK TROF INTO NEW ENG THU FOLLOWED BY A STRONGER COLD FRONT LATE FRI/FRI EVENING. MAINLY DRY WEATHER EXPECTED ALTHOUGH CANT RULE OUT A SHOWER ON FRI WITH THE COLD FRONT. SEASONABLE TEMPS THU WITH SOME MODERATION FRI AHEAD OF THE FRONT. STRONG HIGH PRES BUILDS INTO THE REGION SAT WITH SOMEWHAT COOLER TEMPS...THEN HIGH MOVES S OF NEW ENG SUN WITH RETURN FLOW BRINGING WARMER TEMPS. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THIS AFTERNOON THROUGH TUESDAY NIGHT/... THIS AFTERNOON AND TONIGHT...LOW TO MODERATE CONFIDENCE. VFR CONDITIONS AT MID AFTERNOON WILL DETERIORATE TO LOW END MVFR/IFR WITH EVEN SOME LIFR CONDITIONS POSSIBLE TONIGHT...BUT TIMING HIGHLY UNCERTAIN. MODELS NOT PICKING UP ON A DECK OF LOW CLOUDS/FOG SITTING OFF CAPE COD WHICH MAY BACK INTO EASTERN MA LATER THIS AFTERNOON/EVENING. OTHER AREAS OF LOW CLOUDS AND FOG ARE EXPECTED TO DEVELOP ACROSS THE REST OF THE REGION...BUT TIMING UNCERTAIN. A CLUSTER OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS WILL MAY WORK INTO OUR WESTERN ZONES TOWARD DAYBREAK. TUESDAY AND TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE. A CLUSTER OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE REGION TUE MORNING INTO EARLY AFTERNOON...BEFORE EXITING THE REGION. LOW END MVFR TO IFR CONDITIONS EXPECTED FOR AT LEAST THE MORNING. TEMPORARY IMPROVEMENT TO VFR MAY OCCUR ESPECIALLY ACROSS THE INTERIOR TUE AFTERNOON. A FEW STRONG THUNDERSTORMS MAY WORK INTO WESTERN MA/NORTHERN CT LATE TUE AFTERNOON/EVENING. ISOLATED STRONG WIND GUSTS/HAIL WILL BE POSSIBLE WITH THIS ACTIVITY. EXPECT THE ACTIVITY TO WEAKEN AS IT MOVES INTO EASTERN MA/RI. CONDITIONS THEN IMPROVE TO VFR FROM WEST TO EAST. KBOS TERMINAL...LOW CONFIDENCE. WATCHING A BANK OF LOW CLOUDS/FOG THAT MAY MOVE INTO THE TERMINAL LATE THIS AFTERNOON/EARLY EVENING BUT LOW CONFIDENCE. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOW END MVFR TO IFR EXPECTED TO DEVELOP TONIGHT BUT TIMING UNCERTAIN. OUTLOOK...WEDNESDAY THROUGH FRIDAY... WED THROUGH FRI...HIGH CONFIDENCE. VFR. W/NW GUSTS TO 25 KT ON WED. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE OVER THE WATERS. EASTERLY WINDS 5 TO 10 KTS WILL SHIFT TO THE SOUTH TONIGHT AND INCREASE TO 10 TO 15 KTS WITH GUSTS TO 20 KTS TUESDAY. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. TUE NIGHT...SW WINDS WITH GUSTS TO 20 KT BECOMING NW AFTER MIDNIGHT. SCT SHOWERS AND PATCHY FOG MAY REDUCE VSBYS IN THE EVENING. WED...W/NW WINDS WITH GUSTS TO 25 KT. MARGINAL SCA CONDITIONS POSSIBLE. THU INTO FRI...MAINLY SW WINDS BELOW SCA WITH SEAS BELOW SCA. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/RLG NEAR TERM...FRANK SHORT TERM...RLG LONG TERM...KJC AVIATION...FRANK/KJC MARINE...KJC/RLG
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
349 PM EDT MON MAY 18 2015 .SYNOPSIS... 19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS YET ANOTHER IN A SERIES OF STRONG LONGWAVE TROUGH ABOUT TO PIVOT OUT OF THE SOUTHWESTERN STATES. THE LAST TROUGH IS JUST NOW BEGINNING TO EXIT THE UPPER MIDWEST...BUT HERE COMES THE NEXT ONE CROSSING INTO THE INTER- MOUNTAIN WEST. THANKFULLY FOR OUR LOCAL AREA...THIS INCLEMENT WEATHER WILL REMAIN WELL TO OUR NORTHWEST...WHILE WE REMAIN UNDER THE CONTROL OF WEAK RIDGING ALOFT INTO TUESDAY. AT THE SURFACE...ATLANTIC HIGH PRESSURE IS RIDGING BACK INTO THE NORTHERN FLORIDA PENINSULA THIS AFTERNOON AND WILL CONTINUE TO BOTH SETTLE SLOWLY SOUTHWARD AND WEAKEN DURING THE NEXT 12-24 HOURS. THE POSITION OF THE RIDGE IS RESULTING IN A LIGHT EASTERLY FLOW FOR THE SOUTHERN HALF OF THE AREA...AND A LIGHT AND VARIABLE FLOW TO THE NORTH OF THE TAMPA BAY AREA. ALTHOUGH EASTERLY FLOW IS GENERALLY FAVORABLE FOR CONVECTIVE DEVELOPMENT ALONG THE WEST COAST SEA BREEZE...TODAY IS DIFFERENT FROM PREVIOUS DAYS WITH A SUBSTANTIAL LAYER OF DRY/HOSTILE AIR TOWARD DEEP CONVECTION IN THE MID LEVELS. CAN NOT RULE OUT A FEW ISOLATED STORMS THAT WILL BE ABLE TO SURVIVE THIS DRIER COLUMN TO THE SOUTH OF THE I-4 CORRIDOR...BUT THEY WILL BE FEW AND FAR BETWEEN. MOISTURE PROFILES ARE SLIGHTLY BETTER OVER OUR FAR NORTHERN AREAS...AND ACTUALLY STARTING TO SEE SOME STORMS DEVELOP UP TOWARD PERRY/CROSS CITY. THINK BETTER CHANCES FOR A FEW EVENING STORMS FOR OUR AREA WILL BE UP TOWARD CITRUS/LEVY/NORTHERN SUMTER COUNTY...AS THE SEA-BREEZE SLOWLY MIGRATES INLAND. && .SHORT TERM... SCT EVENING STORMS DECAY QUICKLY WITH THE LOSS OF DIURNAL HEATING LATER THIS EVENING...SETTING UP A GENERALLY DRY AND SEASONABLY WARM MID MAY OVERNIGHT. OVERNIGHT LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S FOR MOST SPOTS...ALTHOUGH NORMALLY WARMER LOCATIONS SUCH AS SOUTHERN PINELLAS COUNTY AND THE ISLANDS OF CHARLOTTE HARBOR WILL STAY EVEN WARMER WITH DEVELOPING LAND BREEZE FLOW OFF THE BAYS. FOR TUESDAY...UPPER RIDGE IS STILL IN PLACE...BUT WILL BEGIN TO WEAKEN WITH HEIGHTS SLOWLY DROPPING THROUGH THE DAY. AT THE SURFACE THE RIDGE AXIS WILL SETTLE DOWN INTO THE CENTRAL OR EVEN SOUTH-CENTRAL FL PENINSULA. THIS MOTION WILL BE FORCED BY THE SLOW APPROACH OF A WEAK FRONT FROM THE NORTH. THIS FRONT MAY REACH AS FAR SOUTH AS THE I-10 CORRIDOR BEFORE TUESDAY IS OVER. THE SYNOPTIC FLOW SOUTH OF THIS FRONT WILL FINALLY SHIFT TO A MORE WESTERLY DIRECTION ACROSS A LARGE PORTION OF OUR AREA. THE WESTERLY FLOW WILL CERTAINLY BE WEAKER DOWN TOWARD FORT MYERS...BUT SHOULD STILL BE PRESENT. THE WEST FLOW WILL ACT TO STEADILY PROGRESS THE SEA BREEZE INLAND...ESPECIALLY FOR THE NATURE COAST. BETTER MOISTURE PROFILES...AND ADDED FOCUS ASSOCIATED WITH THE APPROACHING SYNOPTIC BOUNDARY SHOULD KEEP THE BEST CHANCES FOR DIURNAL CONVECTION ALONG AND NORTH OF THE I-4 CORRIDOR. WILL HAVE 40-50% POPS FOR THE NORTHERN HALF OF THE AREA...AND GENERALLY 20-30% (AT BEST) FURTHER SOUTH. HOWEVER...AS MENTIONED...AS THE SEA-BREEZE MOVES INLAND...RAIN CHANCES WILL DECREASE NEAR THE COAST (EVEN FOR THE NATURE COAST) AS THE AFTERNOON PROGRESSES. BY THE EVENING HOURS...MUCH OF THE STORM ACTIVITY SHOULD BE WELL INLAND. HIGH TEMPERATURES THURSDAY REACH THE MIDDLE 80S AT THE BEACHES WITH UPPER 80S TO LOWER 90S ALONG THE I-75 CORRIDOR AND FURTHER INLAND. && .LONG TERM (WEDNESDAY THROUGH NEXT MONDAY)... WED-FRI: AN UPPER LOW ROTATES OVER EASTERN CANADA WITH A TROUGH THAT PIVOTS FROM THE UPPER MID-WEST TO THE EASTERN SEA BOARD...FLATTENING AND SHIFTING AN UPPER RIDGE OVER THE GULF BACK TO THE WEST. AT THE SURFACE INITIALLY...HIGH PRESSURE SPRAWLS ACROSS THE NORTHERN PLAINS AND MID-MISSISSIPPI VALLEY WITH A FRONT THAT ARCS FROM THE SAINT LAWRENCE VALLEY SOUTH ALONG THE EASTERN U.S. COAST THEN BACK WEST THROUGH THE GULF COASTAL STATES...AND ATLANTIC HIGH PRESSURE RIDGES ACROSS SOUTHERN FL INTO THE GULF. WITH TIME...THE HIGH PRESSURE SAGS SOUTH AS IT BUILDS EAST WITH THE FRONT PUSHING EAST AND SOUTH...WITH THE SOUTHERN/WESTERN END DROPPING DOWN ALONG THE GULF COAST AND THROUGH NORTHERN FL. THE ATLANTIC RIDGE MEANDERS OVER OR OFF SOUTHERN FL. SAT-MON: A PACIFIC UPPER LOW MOVES ACROSS THE GREAT BASIN AND OUT OVER THE PLAINS AS AN OPEN WAVE WITH UPPER RIDGING BUILDING BACK OVER THE GULF THEN SLIDING ACROSS THE SOUTHEAST U.S. TO THE ATLANTIC. THE SURFACE HIGH...BY NOW OVER THE UPPER MID-WEST AND UPPER GREAT LAKES...TRACKS ACROSS THE MID-ATLANTIC STATES THEN OFFSHORE. AS IT DOES IT BRIDGES THE DECAYING FRONT IN THE NORTHERN GULF AND NORTHERN FL AND BUILDS IN ACROSS FL. THE CURRENT FORECAST PHILOSOPHY REMAINS VERY SIMILAR TO THE PAST FEW DAYS. THE ATMOSPHERE CONTINUES WITH AMPLE MOISTURE FOR ISOLATED TO SCATTERED SHOWERS AND STORMS. A WESTERLY FLOW PATTERN SETS UP WED AND CONTINUES THROUGH FRI...WITH A FEW MORNING SHOWERS OR STORMS POSSIBLE ON THE GULF THEN MORE COVERAGE IN THE AFTERNOONS WITH THE HIGHEST INLAND. FOR THE WEEKEND THE PATTERN GOES BACK TO EAST AND SOUTHEAST...AS HIGH PRESSURE BUILDS IN FROM THE NORTH...WITH THE GREATEST SHOWER/STORM COVERAGE IN THE AFTERNOON AND EARLY EVENING ON THE WEST COAST...A RESULT OF SEA BREEZE CIRCULATIONS. TEMPERATURES WILL RUN ABOVE NORMAL...ALTHOUGH THERE MAY BE A SLIGHT DIP LATE IN THE PERIOD. && .AVIATION... VFR CONDITIONS PREVAILING ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA THIS AFTERNOON. JUST A SLIGHT CHANCE FOR AN ISOLATED STORM FOR ANY OF THE TERMINALS THROUGH 00Z...HOWEVER MOST AREAS WILL REMAIN DRY. VFR CONDITIONS GENERALLY PREVAIL FOR THE REMAINDER OF THE OVERNIGHT INTO TUESDAY MORNING. TOWARD THE END OF THE TAF PERIOD (18Z)...A FEW SHOWERS SHOULD START TO FORM ALONG THE SEA- BREEZE IN THE VICINITY OF KTPA/KPIE...AND MAY NEED MENTION IN UPCOMING TAF PACKAGES. && .MARINE... HIGH PRESSURE THAT HAS BEEN OVER THE EASTERN SEABOARD SHIFTS SOUTHWARD AS A WEAK FRONTAL SYSTEM APPROACHES FROM THE NORTH ON TUESDAY. THIS INTERACTION WILL ALLOW FOR THE WINDS TO SHIFT TO A MORE WEST OR NORTHWEST DIRECTION THROUGH THE MIDDLE OF THE WEEK. THE WESTERLY FLOW WILL HELP KEEP THE BEST CHANCES FOR STORMS INLAND THE NEXT SEVERAL DAYS. WINDS AND SEAS REMAIN BELOW HEADLINE CRITERIA. && .FIRE WEATHER... NO SIGNIFICANT FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. THE THUNDERSTORM PATTERN THE NEXT FEW DAYS WILL FAVOR THE SEA-BREEZE MOVING INLAND BEYOND THE I-75 CORRIDOR...AND THEREFORE THE HIGHEST RAIN CHANCES WILL BE AWAY FROM THE COAST AND PROGRESSING INLAND THROUGH THE AFTERNOON AND EARLY EVENING. FOG IMPACT...NO SIGNIFICANT FOG IS EXPECTED FOR THE NEXT FEW DAYS...BUT LATE NIGHT PATCHY GROUND FOG COULD DEVELOP IN AREAS THAT SEE RAIN DURING THE EVENING HOURS. && .PRELIMINARY POINT TEMPS/POPS... TPA 75 87 75 89 / 10 30 20 30 FMY 72 89 74 91 / 10 20 20 40 GIF 72 90 73 92 / 10 30 30 50 SRQ 73 86 74 87 / 20 20 20 30 BKV 69 90 70 90 / 10 30 10 30 SPG 76 87 76 88 / 20 20 20 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...14/MROCZKA LONG TERM/DECISION SUPPORT...09/RUDE
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
148 PM EDT MON MAY 18 2015 .SYNOPSIS... ISSUED AT 135 PM EDT MON MAY 18 2015 A COLD FRONT DROPPING ACROSS THE AREA THIS AFTERNOON WILL BRING A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS THROUGH EARLY EVENING. COOLER AND DRIER AIR WILL SETTLE IN FOR THE WEEK. HIGHS THIS AFTERNOON WILL REACH THE LOWER 80S. LOWS TONIGHT WILL DROP BACK INTO UPPER 40S TO LOWER 50S. EXPECT MUCH COOLER TEMPERATURES TUESDAY AND WEDNESDAY...WITH HIGHS IN THE MID 50S TO LOWER 60S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 358 AM EDT MON MAY 18 2015 DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500 J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY IN ASSOCIATION WITH SOUTHERN STREAM. ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION. EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION LATER THIS AFTERNOON/THIS EVENING. SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR WILL BE POST-FRONTAL. SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL EXPERIENCE CLEARING SKIES IN THE EVENING. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 358 AM EDT MON MAY 18 2015 TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD. SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID 30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE FORECAST AT THIS POINT AND CONTINUE TO MONITOR. ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 135 PM EDT MON MAY 18 2015 ABUNDANT CLOUD COVER AND LACK OF SIGNIFICANT INSTABILITY / BOUNDARY LAYER MOISTURE IS PREVENTING CONVECTIVE DEVELOPMENT OVER THE AREA. ISOLATED SHOWERS HAVE FORMED SOUTH AND EAST OF THE FORECAST AREA AND EXPECT THIS TREND TO CONTINUE THROUGH THE EARLY EVENING. AS OF 17Z THE SURFACE COLD FRONT IS LOCATED OVER THE SOUTHERN TIP OF LAKE MICHIGAN...CROSSING THE IL/IN BORDER. IN THE CLOUD FREE AREAS THE CU FIELD HAS EXPANDED IN THE PAST FEW HOURS AND EXPECT THAT TREND TO CONTINUE THROUGH THE EVENING. FRONTAL PASSAGE WILL BRING IN DRIER AIR AND EXPECT TO SEE AN ABRUPT WIND SHIFT WITH THE PASSAGE. ADDITIONALLY ALL MODELS INDICATE STRONG BOUNDARLY LAYER PRESSURE GRADIENT SO GUSTING WINDS WILL PERSIST THROUGH MUCH OF THE FORECAST PERIOD. LLWS IS NOT FORECAST...HOWEVER WITH THE ORIENTATION OF THE TROF/SFC FRONT...EXPECT TO HAVE A BRIEF AND NARROW CORRIDOR OF TURBULENCE DURING THE PASSAGE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY FOR LMZ043-046. && $$ SYNOPSIS...LEWIS SHORT TERM...MARSILI LONG TERM...AGD AVIATION...LEWIS VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS JACKSON KY
126 PM EDT MON MAY 18 2015 .UPDATE... ISSUED AT 938 AM EDT MON MAY 18 2015 JUST MADE SOME ADJUSTMENTS TO THE FORECAST GRIDS THROUGH THE REST OF THE MORNING. BASED ON CURRENT RADAR IMAGERY...POPS IN OUR SOUTHWESTERN AND WESTERN COUNTIES NEEDED TO BE INCREASED. WENT THROUGH AND INCREASED HOURLY POPS OVER THE NEXT 4 HOURS BY 10 TO 15 PERCENT TO ACCOUNT FOR REAL TIME TRENDS. THIS DID NOT CHANGE THE WORDING IN THE ZONE FORECAST TEXT PRODUCT SO NO UPDATE TO THAT WAS NECESSARY. IN SUMMARY...THE POP...POP12...AND WEATHER TYPE GRIDS HAVE ALL BEEN UPDATED. UPDATE ISSUED AT 709 AM EDT MON MAY 18 2015 A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING. STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 350 AM EDT MON MAY 18 2015 03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY. THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND 17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE THIS AFTERNOON. ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 434 AM EDT MON MAY 18 2015 SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS. HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT. ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND. LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL BE TO OUR WEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 126 PM EDT MON MAY 18 2015 THE PRIMARY FORECAST CONCERN IN THE TAFS WILL BE SHOWER AND THUNDERSTORM ACTIVITY THAT IS CURRENTLY MOVING ACROSS EASTERN KENTUCKY. THESE SHOWERS AND STORMS ARE EXPECTED TO BECOME MORE NUMEROUS AS THE AFTERNOON WEARS ON AS A COLD FRONT APPROACHES FROM THE WEST. THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING. VFR CONDITIONS WILL PREVAIL DURING BREAKS IN THE RAIN. OTHERWISE WE THE TAF SITES COULD EXPERIENCE MVFR TO IFR CONDITIONS WHEN A STRONG SHOWER OR ANY THUNDERSTORMS MOVES PAST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...DJ LONG TERM...HAL AVIATION...AR
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1253 PM CDT MON MAY 18 2015 .AVIATION...A THUNDERSTORM COMPLEX CONTINUES TO PUSH SOUTH THROUGH THE TERMINAL AREA. AEX HAS ALREADY ENCOUNTERED VLIFR AT TIMES WITH HEAVY RAIN. ACTIVITY WILL BE TAPERING OFF AS THE MCS PUSHES ON SOUTH...WILL GO MVFR WITH SOME IFR UNTIL LATER THIS AFTERNOON BECOMING VFR LATE THIS AFTERNOON. COULD SEE SOME MVFR CIG/VIS WITH LIGHT FOG TOWARDS DAYBREAK. VFR LATE MORNING. THE REMAINDER OF THE TERMINALS WILL BE DEALING WITH THE CONVECTIVE COMPLEX THIS AFTERNOON WITH MVFR AS THE SYSTEM WEAKENS UNTIL LATE AFTERNOON. IFR CIGS LATE TNITE BECOMING MVFR DURING THE MORNING ON TUESDAY EXCEPT BPT WHERE IFR CIGS COULD LINGER. MVFR EXPECTED LATE TNITE AT LFT WITH FOG DOWN TO IFR AT ARA. SWEENEY && .PREV DISCUSSION... /ISSUED 1004 AM CDT MON MAY 18 2015/ DISCUSSION... SLOW MOVING MCS ACROSS E TX/C LA WILL BE THE MAIN CONCERN THIS MORNING...ESPECIALLY FOR FLASH FLOOD POTENTIAL ACROSS THIS REGION. FOR THIS...ISSUED FLASH FLOOD WATCH FOR TYLER & N JASPER/NEWTON COUNTIES IN SE TX...AND VERNON/RAPIDES/AVOYELLES PARISHES IN C LA. HIGH POPS REMAIN FOR THE REST OF THE AFTERNOON FROM THE I-10 CORRIDOR NORTHWARD. FURTHER SOUTH SOUTH OF THE I-10 CORRIDOR...POPS DROP OFF SIGNIFICANTLY AT THIS TIME...BUT WILL HAVE TO WATCH IF ANY ADDITIONAL OUTFLOW BOUNDARIES MAY GENERATE PRECIP LATER THIS EVENING AND OVERNIGHT ACROSS THIS REGION. DML PREV DISCUSSION... /ISSUED 701 AM CDT MON MAY 18 2015/ DISCUSSION... FOR THE 12Z TAF PACKAGE. AVIATION... ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC 4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS STRONG AND/OR GUSTY AS YESTERDAY. 13 PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/ SYNOPSIS... LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER THE REGION. DISCUSSION... MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA. RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA. HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING. RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA. WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE EAST OVER THE WEEKEND. THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING IN LOW-LYING OR URBAN AREAS. LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN THE MIDDLE 80S. 24 MARINE... MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL DIMINISH DURING THE MORNING. OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT. 24 && .PRELIMINARY POINT TEMPS/POPS... AEX 77 68 86 70 / 80 30 40 30 LCH 84 72 86 73 / 40 20 30 20 LFT 84 72 86 72 / 60 20 50 20 BPT 84 75 86 74 / 40 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>029. TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR TXZ180-259-260. GM...NONE. && $$ AVIATION...11
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EDT MON MAY 18 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 359 PM EDT MON MAY 18 2015 WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NW ONTARIO INTO THE WRN GREAT LAKES WITH THE LOW CIRCULATION CENTER NEAR CYQT. AT THE SFC...A TROUGH EXTENDED THROUGH NRN LAKE SUPERIOR FROM LOW PRES E OF LAKE SUPERIOR. WITH THE WRAP-AROUND MOISTURE/PCPN MOVING EDGING TOWARD THE AREA...RADARS INDICATED DIURNALLY ENHANCED SCT/NMRS -SHSN/SHRA FROM NE MN INTO NW WI. SOME LIGHT RAIN OR DRIZZLE HAD ALSO DEVELOPED INTO UPSLOPE FLOW LOCATIONS OF NW UPPER MI. TONIGHT...THE COMBINATION OF DEEP MOISTURE SLIDING INTO THE AREA BEHIND THE MID LEVEL LOW AND CAA DROPPING 850 MB TEMPS INTO THE -8C TO -11C RANGE WILL SUPPORT SCT/NMRS -SHRA/-SHSN INTO MAINLY THE WEST HALF OF UPPER MI. THE MOST FAVORABLE UPSLOPE FLOW AND LOW LEVEL CONV WILL SHIFT TO LOCATIONS OVER THE W FAVORED BY NRLY FLOW AND INTO N CNTRL UPPER MI LATE. LOW LEVEL THICKNESS AND WET-BULB ZERO HEIGHTS SUGGEST ANY PCPN WILL CHANGE OVER TO MAINLY SNOW FROM WEST TO EAST THIS EVENING. ALTHOUGH QPF AMOUNTS TO AROUND A TENTH OF AN INCH ARE EXPECTED...WITH THE RELATIVELY WARM GROUND...ANY SNOWFALL AMOUNTS SHOULD REMAIN AROUND A HALF INCH OR LESS...MAINLY ON GRASSY SURFACES. TUE...AS HIGH PRES BUILDS TOWARD THE AREA WITH INCREASINGLY ACYC LOW LEVEL FLOW...AND THE DEEPER MOISTURE DEPARTS TO THE EAST...THE LINGERING SNOW SHOWERS SHOULD GRADUALLY DIMINISH AND END OVER MOST OF THE CWA BY 18Z. THERE MAY BE SOME LIGHT PCPN LINGERING OVER THE EAST DURING THE AFTERNOON. CLOUDS WILL ALSO ONLY SLOWLY DISSIPATE FROM WEST TO EAST DURING THE MID TO LATE AFTERNOON. OTHERWISE...UNSEASONABLY COLD CONDITIONS ARE EXPECTED WITH HIGHS ONLY FROM AROUND 40 NORTH TO THE MID AND UPPER 40S SOUTH AND WEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 320 PM EDT MON MAY 18 2015 A GENERALLY QUIET LONG TERM PERIOD IS IN STORE FOR THE UPPER GREAT LAKES REGION. THIS IS DUE TO THE AREA LARGELY BEING BETWEEN AN UPPER TROUGH OVER EASTERN CANADA AND ANOTHER OVER THE SOUTHWESTERN CONUS. WHILE THE UPPER GREAT LAKES REGION WILL BE BRUSHED BY A FEW WAVES ASSOCIATED WITH THESE FEATURES...THE OVERALL FLOW WILL BE OUT OF THE NORTHWEST OR WEST-NORTHWEST WITH LIMITED MOISTURE. HIGH PRESSURE BUILDS INTO THE AREA ON TUESDAY NIGHT AND REMAINS INTO WEDNESDAY. THE DRY AIR ASSOCIATED WITH THE HIGH WILL DIMINISH ANY LINGERING CLOUDS OVER THE EASTERN CWA QUICKLY DURING THE EARLY EVENING HOURS. THE CLEARING SKIES AND WEAKENING WINDS WILL LEAD TO A COLD NIGHT ACROSS THE AREA ON TUESDAY NIGHT. HAVE FOLLOWED THE LOWER END OF GUIDANCE (WITH PWAT VALUES ONLY AROUND 0.25IN)...WHICH GIVES VALUES IN THE 20S FOR MOST INTERIOR LOCATIONS. ALTHOUGH OUR FROST/FREEZE PROGRAM HASN/T STARTED...WOULD EXPECT A WIDESPREAD FROST (AND A HARD FREEZE FOR THE INTERIOR WEST) ACROSS UPPER MICHIGAN AND PERSONS WITH SENSITIVE PLANTS WOULD BE WISE TO PREPARE FOR A SOLID FROST. A WEAK COLD FRONT DROPS SOUTH FROM ONTARIO WEDNESDAY NIGHT AND WITH THE LACK OF MOISTURE ONLY SHOWED A PERIOD OF PARTLY CLOUDY SKIES AS IT MOVES THROUGH. BEHIND THE FRONT...NORTHERLY FLOW OFF LAKE SUPERIOR WILL KEEP TEMPERATURES COOLER NEAR LAKE SUPERIOR ON THURSDAY (50S) WHILE AREAS INLAND RISE TO OR JUST ABOVE 60. FRIDAY/SATURDAY CONTINUE TO LOOK DRY (WITH TEMPERATURES WARMING TOWARDS NORMAL) AS ANOTHER CANADIAN HIGH PRESSURE MOVES ACROSS THE AREA. THE HIGH WILL DEPART SATURDAY NIGHT...AS ENERGY FROM THE SOUTHWESTERN CONUS TROUGH EJECTS NORTHEAST TOWARDS THE AREA. A SURFACE LOW DEVELOPING IN THE PLAINS WITH THIS FEATURE WILL MOVE INTO IOWA BY SUNDAY NIGHT BEFORE SLOWLY SHIFTING EAST THROUGH SOUTHERN WISCONSIN BY MONDAY NIGHT. AT THIS POINT...EXPECT THE CWA TO BE ON THE NORTHERN EDGE OF MUCH OF THE FORCING (WARM FRONT STALLS OVER SOUTHERN WISCONSIN) AND BEST CHANCES FOR RAIN WILL BE OVER THE SOUTHERN HALF OF THE CWA AS WEAK SHORTWAVES LIFT NORTHEAST ACROSS THE AREA IN THE SOUTHWESTERLY FLOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 128 PM EDT MON MAY 18 2015 WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS. EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS INTO EARLY TUE AFTERNOON. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 PM EDT MON MAY 18 2015 LOW PRES EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE TO THE EAST TONIGHT. A TIGHTENING PRES GRADIENT AHEAD OF HIGH PRES BUILDING TOWARD THE AREA FROM THE NRN PLAINS WILL BOOST NNW WINDS TO 20 TO 30 KNOTS WITH THE POTENTIAL FOR A FEW GALE FORCE GUSTS OVER THE E HALF LATE TONIGHT AND TUE MORNING. WINDS WILL DIMINISH W TO E TUE AFTERNOON/NIGHT THE HIGH BUILDS IN FM THE WEST. WED THRROUGH SAT...WINDS WILL BE UNDER 20KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
320 PM EDT MON MAY 18 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 508 AM EDT MON MAY 18 2015 WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING HRS. TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR (FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT. BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z TUE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 320 PM EDT MON MAY 18 2015 A GENERALLY QUIET LONG TERM PERIOD IS IN STORE FOR THE UPPER GREAT LAKES REGION. THIS IS DUE TO THE AREA LARGELY BEING BETWEEN AN UPPER TROUGH OVER EASTERN CANADA AND ANOTHER OVER THE SOUTHWESTERN CONUS. WHILE THE UPPER GREAT LAKES REGION WILL BE BRUSHED BY A FEW WAVES ASSOCIATED WITH THESE FEATURES...THE OVERALL FLOW WILL BE OUT OF THE NORTHWEST OR WEST-NORTHWEST WITH LIMITED MOISTURE. HIGH PRESSURE BUILDS INTO THE AREA ON TUESDAY NIGHT AND REMAINS INTO WEDNESDAY. THE DRY AIR ASSOCIATED WITH THE HIGH WILL DIMINISH ANY LINGERING CLOUDS OVER THE EASTERN CWA QUICKLY DURING THE EARLY EVENING HOURS. THE CLEARING SKIES AND WEAKENING WINDS WILL LEAD TO A COLD NIGHT ACROSS THE AREA ON TUESDAY NIGHT. HAVE FOLLOWED THE LOWER END OF GUIDANCE (WITH PWAT VALUES ONLY AROUND 0.25IN)...WHICH GIVES VALUES IN THE 20S FOR MOST INTERIOR LOCATIONS. ALTHOUGH OUR FROST/FREEZE PROGRAM HASN/T STARTED...WOULD EXPECT A WIDESPREAD FROST (AND A HARD FREEZE FOR THE INTERIOR WEST) ACROSS UPPER MICHIGAN AND PERSONS WITH SENSITIVE PLANTS WOULD BE WISE TO PREPARE FOR A SOLID FROST. A WEAK COLD FRONT DROPS SOUTH FROM ONTARIO WEDNESDAY NIGHT AND WITH THE LACK OF MOISTURE ONLY SHOWED A PERIOD OF PARTLY CLOUDY SKIES AS IT MOVES THROUGH. BEHIND THE FRONT...NORTHERLY FLOW OFF LAKE SUPERIOR WILL KEEP TEMPERATURES COOLER NEAR LAKE SUPERIOR ON THURSDAY (50S) WHILE AREAS INLAND RISE TO OR JUST ABOVE 60. FRIDAY/SATURDAY CONTINUE TO LOOK DRY (WITH TEMPERATURES WARMING TOWARDS NORMAL) AS ANOTHER CANADIAN HIGH PRESSURE MOVES ACROSS THE AREA. THE HIGH WILL DEPART SATURDAY NIGHT...AS ENERGY FROM THE SOUTHWESTERN CONUS TROUGH EJECTS NORTHEAST TOWARDS THE AREA. A SURFACE LOW DEVELOPING IN THE PLAINS WITH THIS FEATURE WILL MOVE INTO IOWA BY SUNDAY NIGHT BEFORE SLOWLY SHIFTING EAST THROUGH SOUTHERN WISCONSIN BY MONDAY NIGHT. AT THIS POINT...EXPECT THE CWA TO BE ON THE NORTHERN EDGE OF MUCH OF THE FORCING (WARM FRONT STALLS OVER SOUTHERN WISCONSIN) AND BEST CHANCES FOR RAIN WILL BE OVER THE SOUTHERN HALF OF THE CWA AS WEAK SHORTWAVES LIFT NORTHEAST ACROSS THE AREA IN THE SOUTHWESTERLY FLOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 128 PM EDT MON MAY 18 2015 WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS. EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS INTO EARLY TUE AFTERNOON. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT MON MAY 18 2015 LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING AS COLDER AIR ARRIVES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...SRF AVIATION...JLB MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
156 PM EDT MON MAY 18 2015 .UPDATE... ISSUED AT 156 PM EDT MON MAY 18 2015 SCT SHRA HAVE DEVELOPED OVER THE PAST HOUR...A LITTLE FURTHER INLAND THAN EXPECTED (FROM W BRANCH TO NEAR BLACK RIVER). FORECAST ADJUSTED ACCORDINGLY...EXPANDING AND BOOSTING POPS. FORECAST ALSO ADJUSTED EARLIER TO BOOST MAX TEMPS IN PARTS OF NE LOWER...ESPECIALLY NEAR APN/ROGERS...PER OBS. UPDATE ISSUED AT 947 AM EDT MON MAY 18 2015 A STRONG COLD FRONT IS OVER EASTERN WI THIS MORNING. TEMPS ARE PUSHING 70F ALONG THE WI LAKE MI COAST...BUT ARE IN THE LOW 40S IN THE NW CORNER OF THE STATE. THERE IS NO PRECIP ALONG THE FRONT...IN FACT THERE IS NO CLOUD COVER ALONG THE FRONT...THOUGH POST-FRONTAL CLOUD COVER IS SUBSTANTIAL. CLOSER TO HOME...PATCHY MID/HIGH CLOUDS ARE SEEN OVER NORTHERN MI...A BIT THICKER ACROSS EASTERN UPPER. A COUPLE OF POINTS OF CONCERN TODAY. THE COLD FRONT WILL CROSS THE REGION THIS AFTERNOON. ANY POTENTIAL CONVECTION ALONG IT LOOKS TO BE CONFINED TO THE EXTREME SE...AS A GENERAL LACK OF FORCING AND WARM TEMPS ALOFT WILL PROVE A SIGNIFICANT OBSTACLE. WE MIGHT BE ABLE TO MUSTER 500J/KG OF SBCAPE IN FAR SE SECTIONS. THE MOST RECENT HRRR AND RUC RUNS DO TRY TO POP SOMETHING EARLY THIS AFTERNOON...BEFORE DRIER AIR ARRIVES LATER IN THE DAY. HAVE ADDED A SLIGHT CHANCE OF A SHRA EARLY/MID AFTERNOON FROM OSC TO STANDISH. THE OTHER ISSUE IS ANY POTENTIAL FIRE WX CONCERNS. JUST BEHIND A COLD FRONT IS A CLASSIC SUMMER FIRE WX PATTERN FOR US...AS WITH STRONG HEATING WE TEND TO DRY OUT FASTER THAN WE COOL OFF. HOWEVER... IDEALLY COLD FROPA WOULD HAPPEN A FEW HOURS EARLIER...IN THE MORNING AS OPPOSED TO THE PM. HAVE LOWERED DEW POINTS A BIT DURING THE AFTERNOON...BUT HAVE ALSO DONE THE SAME TO LATE-DAY TEMPS AS THE COOLER AIR MAKES INITIAL INROADS. SO DON/T HAVE RH LEVELS GOING BELOW 35 PERCENT OR SO. && .NEAR TERM...(TODAY THROUGH TONIGHT) ISSUED AT 319 AM EDT MON MAY 18 2015 ALL REMAINING SHOWERS HAVE EXITED NE OUT OF OUR CWA EARLY THIS MORNING...WITH NO ADDITIONAL SHOWER ACTIVITY CURRENTLY PRESENT UPSTREAM AS THE WRN GREAT LAKES REMAINS FIRMLY WITHIN THE DRY SLOT ASSOCIATED WITH DEEP LOW PRESSURE NOW CENTERED OVER NRN MINNESOTA. SKIES HAVE AT LEAST PARTIALLY CLEARED IN RESPONSE TO THIS DRIER AIR WORKING ITS WAY INTO MICHIGAN. OUR CWA WILL REMAIN WITHIN THE DRY SLOT THRU MUCH OF TODAY AS THE SURFACE LOW CENTER MAKES SLOW EASTWARD PROGRESS THRU UPPER MICHIGAN AND INTO QUEBEC BY 00Z TUESDAY. EXPECT A PARTLY TO MOSTLY SUNNY AND DRY DAY ALONG WITH UNSEASONABLY WARM TEMPS FOR MOST OF OUR CWA. AFTERNOON HIGHS WILL ONLY REACH TO AROUND 70 DEGREES ACROSS ERN UPR MICHIGAN WHERE CAA ON THE BACKSIDE OF THE LOW WILL INITIALLY BEGIN THIS AFTERNOON. BUT TEMPS WILL ONCE AGAIN WARM INTO THE UPPER 70S AND LOWER 80S FOR NRN LWR MICHIGAN (COOLER NEAR THE LAKES)...GIVING US ONE LAST DAY OF SUMMER WARMTH BEFORE THE REALITY OF NRN MICHIGAN IN MID MAY KICKS BACK IN ON TUESDAY. LOW LEVEL MOISTURE/CLOUDS WILL WRAP BACK INTO NRN MICHIGAN TONIGHT ON THE BACKSIDE OF THE DEPARTING LOW. THE CAA BEHIND THE LOW WILL BE RAPID AND IMPRESSIVE THRU THE NIGHT...AS 850 MB TEMPS DROP FROM +13C THIS AFTERNOON TO AROUND -2C BY 12Z TUESDAY. AT THIS POINT...THINK THE ONLY LOCATION THAT WILL SEE A CHANCE OF SHOWERS WILL BE NW CHIPPEWA COUNTY THIS AFTERNOON AND TONIGHT WHERE CAA AND LOW LEVEL WRAP AROUND MOISTURE ADVECTION TAKE PLACE SOONEST. THE REST OF OUR CWA SHOULD BE GENERALLY DRY...BUT WITH DEEP CYCLONIC FLOW... INCREASING LOW LEVEL MOISTURE AND EVENTUALLY SOME OVER-LAKE INSTABILITY DEVELOPING LATE TONIGHT THANKS TO CAA...WILL NEED TO KEEP AN EYE ON THE POTENTIAL FOR SOME SHOWER ACTIVITY TO DEVELOP. FOR NOW...WILL MAINTAIN A DRY FORECAST WITH INCREASING CLOUDS TONIGHT. TEMPS WILL BE NOTICEABLY COLDER TONIGHT...WITH LOWS FALLING MAINLY INTO THE 40S. && .SHORT TERM...(TUESDAY THROUGH WEDNESDAY NIGHT) ISSUED AT 319 AM EDT MON MAY 18 2015 HIGH IMPACT WEATHER: TUESDAY NIGHT LOW TEMPERATURES/FROST POTENTIAL FOR N LOWER. FORECAST CHALLENGE: HOW FAR WILL THE TEMPERATURES FALL TUESDAY NIGHT. (05/19)TUESDAY...WITH THE FRONT SEVERAL HUNDRED MILES TO THE EAST, THE COLD AIR WILL BE PUSHING INTO THE REGION THROUGH THE DAY. TEMPERATURES WILL PRETTY MUCH GO NO WHERE AS THE 850 MB TEMPERATURES FALL FROM AROUND 0C TO ABOUT -4 OR -6C DEPENDING ON THE MODEL. THE ECMWF IS BEGINNING TO BACK OFF ON THE -8C AIR THAT IT WAS ADVERTISING THE LAST 2 RUNS, WITH IT AROUND -6C AT ANJ. WHILE THE GFS WILL BE AROUND -4C. WILL HAVE A MIX OF RAIN AND SNOW IN THE AFTERNOON AS THE SFC TEMPERATURES BEGIN TO FALL INTO THE UPPER 30S BY IN E UPPER. THE MOISTURE DOESN`T LOOK DEEP ENOUGH FOR PRECIPITATION IN N LOWER SO WILL LEAVE IT OUT OF THERE, JUST MOSTLY CLOUDY. OVERNIGHT, THE RH AT 850 MB AND IN THE 700-500 MB LAYER WILL DROP TO LESS THAN 20% ON BOTH MODELS BY 12Z. AND WITH THE 850 MB TEMPERATURES MAINTAINING AROUND 0C OR BELOW, AND, AT LEAST ON THE ECMWF, THE WINDS WILL PROBABLY DECOUPLE, FROST IS PROBABLE, AND MAYBE A FREEZE IS POSSIBLE. FOR NOW WILL HAVE PATCHY AND AREAS OF FROST, BUT THIS IS LOOKING MORE WIDE SPREAD IF THE WINDS DROP OFF LIKE THE ECMWF WOULD SUGGEST. (05/20)WEDNESDAY...LOOKS TO BE A SUNNY TO PARTLY CLOUDY DAY WITH LOW RELATIVE HUMIDITY AND HIGH TEMPERATURES, BELOW NORMAL (LOOKS LIKE NOW AROUND 5 TO 10 DEGREES BELOW) IF THE MODELS PAN OUT. OVERNIGHT, A 500 MB SHORTWAVE PUSHES THROUGH THE FORECAST AREA, BUT THE MODELS SUGGEST THAT ONLY THE MOISTURE IN THE 700-500 MB LAYER WOULD INCREASE, IF ANY AT ALL. SO WILL EXPECT THAT THE NIGHT WOULD REMAIN DRY. MAY IDEAS IS THAT THE SKY REMAINS CLEAR TO PARTLY CLOUDY, SO TEMPERATURES LOOK TO BE IN THE LOWER TO MID 30S, SO ANOTHER FROST NIGHT? PUT PATCHY IN FOR THE INLAND AREAS, AND LEFT THE LAKE SHORES FROST FREE WHERE THE AIR TEMPERATURE IS EXPECTED TO BE A LITTLE WARMER. && .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 319 AM EDT MON MAY 18 2015 EXTENDED (THURSDAY THROUGH SUNDAY)...WITH THE 500 MB TROUGH THAT PARKS ITSELF OVER THE NEW ENGLAND STARTING TUESDAY AND HANGS THERE THROUGH FRIDAY. FRIDAY, THE LOW BEGINS TO MOVE OUT ALLOWING THE 500 MB RIDGE TO BUILD IN THE UPPER GREAT LAKES. SO WHAT DOES THIS MEAN FOR THE LONG TERM? SFC HIGH PRESSURE WILL CAMP OUT IN THE UPPER GREAT LAKES THROUGH THE WEEK, KEEPING THE AREA DRY THROUGH SATURDAY NIGHT, AND THE 500 MB PATTERN WILL KEEP THE HIGH TEMPERATURES AROUND OR BELOW NORMAL THROUGH THE WEEK WHEN THE NORMAL HIGH TEMPERATURES IN GAYLORD AND SAULT STE. MARIE ARE IN THE UPPER 60S. SUNDAY, THE MODELS BEGIN TO KEY IN ON THE NEXT 500 MB LOW THAT MOVES OUT OF THE CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS, PRODUCING SHOWERS AND POSSIBLY THUNDERSTORMS AS THE WARM FRONT PUSHES UP THROUGH THE STATE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 126 PM EDT MON MAY 18 2015 VFR THRU THIS EVENING. MVFR CIGS DEVELOPING OVERNIGHT PLN/TVC/MBL. LOW PRESSURE IS CENTERED JUST NE OF LAKE SUPERIOR...AND WILL MOVE QUICKLY INTO QUEBEC THRU THIS EVENING. STRONG COLD FRONT WILL CROSS NORTHERN MI THIS AFTERNOON/EARLY EVENING. MINIMAL RISK OF PRECIP WITH THE FRONT...BUT LOW LEVEL MOISTURE WILL INCREASE IN THE MUCH COLDER AIR BEHIND THE FRONT. MVFR CIGS WILL BECOME ESTABLISHED AT PLN/TVC/MBL LATE TONIGHT...AND CONTINUE INTO TUE MORNING. APN WILL STAY VFR. SW WINDS WILL BE GUSTY (20-25KT) THIS AFTERNOON. WINDS VEER W AND NW TONIGHT...BECOMING LESS GUSTY FOR A PERIOD...BEFORE BLUSTERINESS RETURNS TUE MORNING. && .MARINE... ISSUED AT 319 AM EDT MON MAY 18 2015 WINDS AND WAVES WILL APPROACH SCA CRITERIA TODAY AND ESPECIALLY TONIGHT AS CAA DEVELOPS ON THE WAKE OF A DEPARTING LOW. AT THIS POINT...EXPECT CONDITIONS SHOULD REMAIN UNDER CRITERIA...SO WILL NOT ISSUE A SCA AT THIS TIME. STRONGER NW WINDS WILL LIKELY DEVELOP ON TUESDAY AS CAA STRENGTHENS BEHIND THE DEPARTING LOW. AREAS OF FOG AND LOW STRATUS WILL CONTINUE TO IMPACT OUR NEARSHORE AREAS THRU THIS MORNING BEFORE MIXING OUT THIS AFTERNOON. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LHZ345>347. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ341-342. LS...NONE. && $$ UPDATE...JAZ NEAR TERM...MLR SHORT TERM...JSL LONG TERM...JSL AVIATION...JAZ MARINE...MLR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 PM EDT MON MAY 18 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 508 AM EDT MON MAY 18 2015 WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING HRS. TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR (FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT. BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z TUE. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON MAY 18 2015 TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE 17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING. 850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT 12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH DIMINISHES SIGNIFICANTLY. EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF THE INTERIOR W HALF OF UPPER MI/. EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND 0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY /ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/. DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 128 PM EDT MON MAY 18 2015 WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS. EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS INTO EARLY TUE AFTERNOON. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 508 AM EDT MON MAY 18 2015 LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING AS COLDER AIR ARRIVES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...JLB MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
105 PM CDT MON MAY 18 2015 .UPDATE FOR 18Z AVIATION DISCUSSION... && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 352 AM CDT MON MAY 18 2015 SUB-1000MB LOW OVER NORTHERN MN CONTINUES TO FACILITATE WINDY CONDITIONS AND STRATUS CLOUDS OVER THE FORECAST AREA EARLY THIS MORNING. SLIGHT LOOSENING OF THE PRESSURE GRADIENT AS THE TROUGH WEAKENS AND LIFTS TO THE GREAT LAKES SHOULD ALLOW WINDS TO DIP BELOW WIND ADVISORY CRITERIA TODAY /SUSTAINED 30 MPH/...SO WILL NOT REISSUE THE WIND ADVISORY. HOWEVER...IT WILL REMAIN QUITE BREEZY THROUGH THE DAY. MEANWHILE...THE EXTENSIVE AREA OF SHOWERS OVER NORTHERN MN AND THE EASTERN DAKOTAS WILL SLIP SLIGHTLY FARTHER SOUTH INTO CENTRAL MN THIS MORNING. HAVE MAINTED HIGH CHANCE POPS ACROSS CENTRAL MN TOWARD NORTHERN WI...AND ALSO INCLUDED SPRINKLES FARTHER SOUTH TO INCLUDE THE TWIN CITIES AND AREAS DOWN TOWARD SOUTH CENTRAL MN. TEMPERATURES TODAY WILL BE QUITE CHILLY...AVERAGING 25 TO 30 DEGREES BELOW NORMAL. HIGHS WILL STRUGGLE TO REACH 40 IN WEST CENTRAL MN NEAR ALEXANDRIA...WHILE THE REMAINDER OF THE AREA WILL SEE HIGHS IN THE 40S. TEMPS TONIGHT WILL BE AROUND 10 TO 15 DEGREES BELOW NORMAL...WITH ANTICIPATED LOWS IN THE LOW TO MID 30S. HAVE INCLUDED THE MENTION OF FROST IN THE FORECAST...BUT WILL HOLD OFF ON ANY SORT OF A FROST/FREEZE ADVISORY GIVEN SCT-BKN CLOUDS ARE EXPECTED TO HANG IN UNTIL THE EARLY MORNING HOURS OF TUESDAY...AND WINDS WILL BE IN THE 6-10 MPH RANGE. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 352 AM CDT MON MAY 18 2015 NOT MUCH CHANGE IN THE EXTENDED PERIOD AS WAS PREVIOUSLY ADVERTISED WITH A COOL PERIOD THIS WEEK...THEN WETTER NEXT WEEKEND. THE MEAN UPPER LEVEL FLOW WILL START THIS WEEK FROM THE W-NW DIRECTION WHICH SHOULD KEEP A STORM SYSTEM MOVING OUT OF THE SOUTHERN ROCKIES AND INTO THE MIDWEST...SOUTH OF OUR REGION. BASICALLY THE CONFLUENT FLOW ALOFT AND DRY E/NE FLOW IN THE BOUNDARY LAYER WILL KEEP ANY PRECIPITATION CHANCES IN FAR SOUTHERN MN. EVEN IN THIS AREA...VERY LIGHT PRECIPITATION IS EXPECTED...BUT THE DENSER CLOUD COVER...AND THE CHANCE OF PRECIPITATION...WILL KEEP TEMPS A FEW DEGREES COOLER THAN NORTH IN CENTRAL MN WHERE MORE SUNSHINE WILL OCCUR. CLIMATOLOGY...THIS WEEK WILL REMAIN ON THE COOL SIDE WITH AFTN HIGHS SLOWLY REBOUNDING INTO THE UPPER 60S/LOWER 70S BY THURSDAY/FRIDAY. THE UPPER LEVEL FLOW WILL BEGIN TO BUCKLE BY THE END OF THE WEEK AS A STORM SYSTEM KICKS OUT OF THE SW CONUS...AND A STRONGER RIDGE BUILDS IN THE SE CONUS. THIS WILL LEAD TO A WARMER AND UNSETTLED PATTERN BY NEXT WEEKEND. HOWEVER...BASED ON THE CURRENT MODELS DEPICTION OF THE MAIN SFC FRONT ALONG AND SOUTH OF MN/IA BORDER...MN AND WESTERN WI MAY BE ON THE COOL SIDE WITH OCCASIONAL SHRA/TSRA...BUT NOT AS WARM. THIS COULD CHANGE IF THE RIDGE IN THE SOUTHEASTERN CONUS STRENGTHENS AND ALLOWS THIS SFC FRONT TO MOVE FURTHER NORTHWARD INTO MN. THIS WOULD ALSO LEAD TO MORE SVR WX CHANCES AS WE WOULD BE IN THE WARM SECTOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1257 PM CDT MON MAY 18 2015 WIDESPREAD MVFR CIGS ACROSS THE AREA. SOME RESIDUAL SPRINKLES/LIGHT SHOWERS AROUND. STILL HAVE COLD POOL TO MOVE OVER THE AREA INTO TONIGHT.THE HRRR CONTINUES TO SHOW SOME ISOLD -SHRA INTO TONIGHT AS WEAK SURFACE TROUGH MOVES SOUTHEAST OVER THE NORTHERN CWA. THIS MAY AFFECT CLOUD TRENDS...ESPECIALLY TO THE EAST OVERNIGHT. SOME DRIER AIR TRYING TO WORK OVER SOUTHWEST AREA...WITH MORE CUFORM CLOUDS THIS AFTERNOON. MAY SEE HIGHER END MVFR OR IFR CONDITIONS AT A FEW LOCATIONS IN MN THIS AFTERNOON. WILL TRY AND SCATTERED CLOUDS TO THE WEST OVERNIGHT AS DRIER AIR MOVES EAST. THEY MAY HOLD FIRM FARTHER EAST...BUT OVERALL CONFIDENCE IN CLOUD TREND IS LOW AT THIS TIME. WEST TO NORTHWEST WINDS OVER THE AREA GUSTS OVER 30KT TO THE WEST...SHOULD GRADUALLY DIMINISH INTO THE EVENING FROM WEST TO EAST. NORTHWEST/NORTH WINDS GENERALLY 10-15 KTS INTO TUE WITH CLEARING TREND. KMSP... MVFR CIGS INTO THE NIGHT WITH VFR TRENDS INTO TUESDAY MORNING. SOME QUESTION AS TO HOW LOW CIGS MAY DROP AGAIN INTO THE HE EVENING AS A WEAK SURFACE TROUGH APPROACHES FROM THE NORTH. WILL HAVE TO MONITOR THIS INTO THE EVENING. SOME SMALL CHANCE OF -RA/-DZ ASSOCIATED WITH THIS FEATURE AS WELL...BUT FORCING IS LACKING. NORTHWEST WINDS A BIT GUSTY INTO THE EVENING BECOMING MORE NORTH INTO TUESDAY. /OUTLOOK FOR KMSP/ WED...VFR. WINDS N 5 KTS. THU...VFR. WINDS NNW 5 TO 10 KTS. FRI...VFR. WINDS NE 5 TO 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...JLT AVIATION...DWE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1104 AM CDT MON MAY 18 2015 .UPDATE...LARGE CONVECTIVE COMPLEX AFFECTING MAINLY SW PORTIONS HAS BEEN RESPONSIBLE FOR PROLIFIC RAINFALL AMOUNTS OVERNIGHT AND THIS MORNING. WHILE AREAS AROUND VICKSBURG SAW THE GREATEST AMOUNTS OVERNIGHT AND EARLY THIS MORNING...EMPHASIS NOW HAS SHIFTED SOUTH WITH THE ADVANCING COLD POOL AND A NEW SURGE OF CONVECTION DEVELOPING OVER W LA. MOISTURE TRANSPORT VECTORS FROM THE HRRR AND NAM SUGGEST THAT THE HEAVIEST RAINFALL THIS AFTERNOON WILL OCCUR IN FAR EC LA AND SW PORTIONS OF MS. HAVE THEREFORE REPOSITIONED THE FFA TO ACCOUNT FOR THIS. HAD TO MODIFY POP/WX GRIDS BASED ON CURRENT TRENDS. ALSO...MADE ADJUSTMENT TO TEMPS AS CLOUDS/RAIN WILL SIGNIFICANTLY IMPACT WARMTH OVER THE AREA THIS AFTERNOON./26 && .AVIATION...AREA RADARS WERE PICKING UP NUMEROUS SHRA/TSRA ACROSS THE WEST HALF OF THE REGION. EXPECT IT TO SPREAD ACROSS THE REGION CAUSING PERIODS OF CIG/VISBY IN IFR/MVFR CONDITIONS IN HEAVIER RAINFALL. EXPECT RAIN CHANCES TO CONTINUE THROUGH TUESDAY MORNING. SO MVFR/IFR CIGS WILL CONTINUE WITH PERIODS OF RAIN OVERNIGHT INTO TUESDAY MORNING./17/ && .PREV DISCUSSION... /ISSUED 447 AM CDT MON MAY 18 2015/ DISCUSSION... SHORT TERM (TODAY THROUGH TUESDAY NIGHT)...IT HAS BEEN AN ACTIVE OVERNIGHT PERIOD AS AN MCV HAS INCITED PERSISTENT CONVECTION ACROSS THE REGION. AFTER A TEMPORARY LULL IN INTENSITY/COVERAGE SHORTLY AFTER MIDNIGHT...CONSIDERABLE NEW DEVELOPMENT OCCURRED ACROSS NORTH LOUISIANA OVER THE PAST FEW HOURS. MODEL GUIDANCE...PARTICULARLY HIGH RES GUIDANCE...HAS HAD AN EXTREMELY DIFFICULT TIME WITH DETAILS IN THIS PATTERN DUE TO POOR INITIALIZATION. THUS LESS FOCUS WAS PLACED ON ACTUAL QPF OUTPUT THAN THE OVERALL SYNOPTIC PICTURE. WITH THAT IN MIND...AN UNSEASONABLY MOIST AIRMASS CURRENTLY RESIDES ACROSS THE AREA (PARTICULARLY THE NORTHWESTERN PORTION OF THE CWA)...WITH PWATS AROUND 2 INCHES (NEAR RECORD MAX FOR THIS TIME OF YEAR). A SURFACE FRONT CURRENTLY EXTENDING ACROSS THE MISSOURI VALLEY WILL SINK SOUTHWARD TOWARD THE AREA THROUGH THE DAY. AS AN UPPER SHORTWAVE...WHICH IS CURRENTLY FORCING CONVECTION JUST WEST OF THE REGION...MOVES EASTWARD SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL OCCUR ACROSS THE CWA TODAY. RADAR ESTIMATES SUGGEST 2 TO 4 INCHES HAVE ALREADY OCCURRED ACROSS PORTIONS OF THE DELTA...WITH PERHAPS EVEN HIGHER LOCALIZED AMOUNTS. THUS IN MANY AREAS IT WILL TAKE LITTLE ADDITIONAL RAIN TO CAUSE FLASH FLOODING. A FLASH FLOOD WATCH WAS POSTED FOR MUCH OF THE DELTA REGION FOR TODAY TO HIGHLIGHT THIS POTENTIAL. THE SURFACE FRONT WILL SAG INTO THE AREA AND STALL ON TUESDAY... PROVIDING A CONTINUED FOCUS FOR SCATTERED CONVECTION ACROSS THE AREA. AS HAS BEEN THE CASE OVER THE PAST FEW DAYS...THOUGH LITTLE TO MARGINAL WIND SHEAR IS EXPECTED SUFFICIENT INSTABILITY MAY EXIST TO GENERATE SOME STRONG/SEVERE CONVECTION. HOWEVER THIS THREAT SHOULD BE ISOLATED ENOUGH TO LEAVE MENTION OUT OF THE HWO AT THIS TIME. /DL/ LONG TERM (WEDNESDAY THROUGH MONDAY)...A SUMMERLIKE PATTERN WILL CONTINUE ACROSS THE REGION THROUGH THE WEEK AS MID/UPPER LEVEL RIDGING REMAINS IN PLACE. A MOIST AIRMASS WILL BE PRESENT OVER THE REGION AS PW VALUES REMAIN AROUND 1.6-1.9 INCHES. SOME DRIER AIR MAY BE PRESENT ACROSS THE NORTH WHICH COULD LIMIT CONVECTION AT TIMES. A WEAK SFC FRONT WILL REMAIN ACROSS THE SOUTHERN PORTIONS OF THE FORECAST AREA AND WILL LIKELY SERVE AS FOCUSING MECHANISM FOR MAINLY DIURNAL SHOWERS AND THUNDERSTORMS. WARM CONDITIONS WILL PREVAIL THROUGH THE WEEK INTO THE WEEKEND. ANOTHER POTENT WEATHER SYSTEM ACROSS THE PLAINS WILL TRACK TO THE NORTHEAST AND SEND ANOTHER FRONT IN OUR DIRECTION FOR EARLY NEXT WEEK...WHICH COULD BRING MORE RAIN TO THE REGION. /28/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 79 69 86 68 / 77 37 43 25 MERIDIAN 84 69 85 67 / 52 37 46 20 VICKSBURG 78 69 86 69 / 100 43 43 25 HATTIESBURG 87 70 87 69 / 51 33 46 26 NATCHEZ 81 69 85 69 / 100 39 45 31 GREENVILLE 79 69 84 68 / 100 36 31 30 GREENWOOD 79 68 84 66 / 100 37 32 26 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR MSZ047-048-053- 054-059>063. LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ015-016- 023>026. AR...NONE. && $$
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
339 PM PDT MON MAY 18 2015 .SYNOPSIS...AN AREA OF LOW PRESSURE WILL MOVE EAST ACROSS NEVADA TONIGHT RESULTING IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS AROUND ESPECIALLY EARLY AND TO THE NORTH OF LAS VEGAS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED AGAIN ON TUESDAY ACROSS THE SOUTHERN GREAT BASIN. MOST AREAS WILL SEE DRY CONDITIONS ON WEDNESDAY AND WEDNESDAY NIGHT. A NEW STORM SYSTEM WILL APPROACH THE AREA ON THURSDAY THEN MOVE ACROSS ON FRIDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. A SLOW DRYING AND WARMING TREND IS EXPECTED FOR THE MEMORIAL DAY WEEKEND. && .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT. CLARK AND LINCOLN COUNTIES HAVE REALLY SEEN AN ACTIVE DAY AS SHOWERS AND THUNDERSTORMS GOT GOING SHORTLY AFTER DAYBREAK IN THE NORTHEAST QUADRANT OF A MID/UPPER LEVEL LOW. THE CENTER OF THIS LOW COULD BE SEEN THIS AFTERNOON ON WATER VAPOR AND SATELLITE OVER DEATH VALLEY NATIONAL PARK. DESPITE ONLY 0.53 INCH OF PWAT IN THIS MORNING`S NWS VEGAS SOUNDING AND RELATIVELY LOW-TOPPED CONVECTION, THERE HAVE BEEN SOME IMPRESSIVE PRECIPITATION TOTALS TODAY WHERE STRONGER STORMS DEVELOPED OR ACTIVITY TRAINED. A FEW SPOTS IN SUMMERLIN WEST PICKED UP OVER AN INCH OF RAIN AS WELL AS ONE GUAGE JUST SOUTH OF INSPIRADA IN HENDERSON. WHILE WIDESPREAD HEAVY RAIN IS NOT EXPECTED THIS EVENING, ANY SLOWER MOVING OR STRONGER ACTIVITY COULD DUMP A HALF OF AN INCH OR MORE OF RAIN ESPECIALLY IF IT TRAINS. GIVEN THE ATMOSPHERE HAS BECOME WORKED OVER IN AND AROUND THE LAS VEGAS VALLEY EARLIER TODAY, WE THINK THAT THE INTENSITY OF ACTIVITY IMMEDIATELY IN AND AROUND THE VALLEY SHOULD STAY TOWARD THE LOW-MODERATE END. HOWEVER, CLOSER TO THE LOW CENTER IN THE NORTHEAST QUADRANT WHERE ACTIVITY WAS MORE LIMITED EARLIER TODAY, THINGS COULD BE MORE ACTIVE IN ESMERALDA, EASTERN INYO AND CENTRAL NYE COUNTIES. THE HRRR AND LOCAL NMM AND ARW MODELS ALL KEY IN ON THESE AREAS FOR ACTIVITY TO DEVELOP OR PERSIST THIS EVENING AND THUS POPS WERE ADJUSTED UP IN THESE AREAS. THESE AREAS MAY BE THE SLOWEST TO SEE ACTIVITY END THIS EVENING WHILE ELSEWHERE THINGS SHOULD END BETWEEN 7 AND 9 PM. LOW FREEZING LEVELS HAVE ALSO RESULTED IN STRONGER ACTIVITY PRODUCING HAIL WITH REPORTS EARLIER TODAY AS LARGE AS AN INCH IN DIAMETER IN THE MOST INTENSE ACTIVITY. IN ADDITION SNOW LEVELS AROUND 8500 FEET WERE NOTED AND A LIGHT COATING TO AN INCH OR TWO OF SNOW IS POSSIBLE IN THE HIGHEST ELEVATIONS UNDER ANY SHOWER OR THUNDERSTORM ACTIVITY OVERNIGHT. THE LOW CENTER WILL TRANSITION ACROSS THE AREA TONIGHT WHICH WILL PLACE US ON THE BACK SIDE OF THE LOW FOR TUESDAY. LINGERING ENERGY AND MID-LEVEL MOISTURE WILL BE ENOUGH TO TOUCH OFF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MAINLY ACROSS THE SOUTHERN GREAT BASIN BUT OUTSIDE OF LINCOLN AND CENTRAL NYE COUNTIES THE COVERAGE OF ACTIVITY SHOULD BE LOWER TOMORROW. ONCE AGAIN, LOW FREEZING LEVELS WILL ALLOW FOR HAIL IN ANY STRONGER ACTIVITY. HIGH TEMPS SHOULD WARM UP SEVERAL DEGREES AS DRIER AIR WORKS IN AND ERODES AWAY THE CLOUDS OVER THE MOJAVE DESERT. ANOTHER LOW WILL APPROACH THE COAST OF CALIFORNIA ON WEDNESDAY. THIS WILL SPREAD LOTS OF HIGH LEVEL MOISTURE INTO THE AREA AS THE JET STREAM PASSES BY ACROSS SOCAL INTO ARIZONA RESULTING IN A DECENT AMOUNT OF CIRRUS CLOUDS TO START TO THE DAY AND AGAIN WEDNESDAY NIGHT. OTHERWISE, THE BEST MOISTURE AND INSTABILITY WILL BE OVER THE SOUTHERN SIERRA CREST AND EASTERN SLOPES AS WELL AS ESMERALDA COUNTY AND A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE HERE MAINLY IN THE AFTERNOON. THE REST OF THE AREA LOOKS DRY WITH WINDS PICKING UP FROM THE SOUTH IN THE AFTERNOON AND EVENING AND GUSTING TO 20-30 MPH. HIGH TEMPS SHOULD WARM BACK UP ANOTHER 3-5 DEGREES OVER TUESDAY. THIS LOW WILL EVENTUALLY LOOP BACK OUT AND MERGE WITH ANOTHER LOW THAT HEADS TOWARD THE COAST ON THURSDAY. .LONG TERM...THURSDAY THROUGH MONDAY. THE NEXT UPPER LOW WILL APPROACH THE CENTRAL CALIFORNIA COAST THURSDAY. A SHORTWAVE ROTATING AROUND THE LOW WILL MOVE NORTHEAST INTO CALIFORNIA AND NEVADA DURING THE DAY. AN AREA OF DIFFLUENCE AND DECENT MID LEVEL MOISTURE WILL LEAD TO A CHANCE OF SHOWERS OVER MUCH OF INYO COUNTY AND ACROSS ESMERALDA...CENTRAL NYE AND NORTHERN LINCOLN COUNTIES. THE UPPER LOW WILL MOVE INLAND THURSDAY NIGHT AND ACROSS SOUTHERN NEVADA INTO NORTHWEST ARIZONA FRIDAY. PRECIPITATION CHANCES WILL THUS SPREAD EAST ACROSS A GOOD PORTION OF THE FORECAST AREA...MAINLY NORTH OF INTERSTATE 40. WITH THE LOW MOVING OVERHEAD...HIGH TEMPERATURES FRIDAY WILL BE SOME 10 TO 15 DEGREES BELOW NORMAL. PRECIPITATION CHANCES WILL DECREASE AND SHIFT NORTHEAST FRIDAY NIGHT AS THE LOW STARTS TO EXIT THE AREA. HOWEVER...A SHORTWAVE TROUGH FOLLOWING BEHIND FROM THE NORTH WILL BRING A CHANCE OF SHOWERS SATURDAY TO AREAS MAINLY NORTH OF LAS VEGAS. FOR SUNDAY THROUGH MONDAY THE MODELS ARE NOT IN VERY GOOD AGREEMENT BUT IN GENERAL IT LOOKS LIKE THERE WILL BE SOME SORT OF UPPER TROUGH ROUGHLY OVER NORTHERN NEVADA. THIS WOULD KEEP AT LEAST A SLIGHT CHANCE OF SHOWERS OVER THE FAR NORTHERN PART OF THE FORECAST AREA AND I LEFT SLIGHT CHANCE POPS IN FOR THOSE AREAS. && .AVIATION...FOR MCCARRAN...SCT SHRA AND ISO TSRA WILL CONTINUE THROUGH AROUND 03Z TUESDAY. BASES COULD LOWER TO 5K-8K FEET IN AND NEAR SHRA/TSRA AND WINDS MAY BECOME GUSTY AND ERRATIC POTENTIALLY IMPACTING CONFIGURATIONS. OVERALL IT APPEARS WE SHOULD SEE AN DOWNWARD TREND IN SHRA AND TSRA ACTIVITY BY LATER THIS EVENING IN THE LAS VEGAS VALLEY AS WELL AS IN MOST OF THE APPROACH CORRIDORS WITH THE BEATTY CORRIDOR LIKELY TO SEE ACTIVITY LINGER THE LONGEST. WINDS OTHERWISE SHOULD FOLLOW TYPICAL DIURNAL DIRECTIONS AT 8 KTS OR LESS THROUGH TUESDAY EVENING WITH CLOUDS GRADUALLY DECREASING AND MAINLY ABOVE 10K FEET. ALTHOUGH CONDITIONS LOOK DRY IN THE LAS VEGAS VALLEY ON TUESDAY, ISO SHRA/TSRA ARE POSSIBLE IN THE SPRING MOUNTAINS. ADDITIONAL SHRA AND TSRA CHANCES EXIST FOR FRIDAY AND FRIDAY NIGHT IN THE LAS VEGAS VALLEY. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...SHRA/TSRA ARE EXPECTED MAINLY NORTH OF KIYK-KLAS-KIGM LINE WITH ACTIVITY GRADUALLY DIMINISHING BETWEEN 03Z AND 06Z TUESDAY. ISOLATED SHRA/TSRA ACTIVITY MAY LINGER THOUGH THE NIGHT ESPECIALLY IN THE SOUTHERN GREAT BASIN. SHRA/TSRA WILL AGAIN BE POSSIBLE ON TUESDAY ESPECIALLY AFTER 18Z NORTH OF KIYK-KDRA-KACZ LINE. WINDS MAY BE GUSTY AND ERRATIC IN AND NEAR SHRA/TSRA WITH CIGS LOWERING TO 5K- 8K FEET. OTHERWISE LOOK FOR WINDS TO TREND TOWARD TYPICAL DIURNAL DIRECTIONS AT 10 KTS OR LESS WITH SCT-BKN CLOUDS AOA 10K FEET. && .SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ SHORT TERM/AVIATION...STACHELSKI LONG TERM...HARRISON FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
309 PM EDT MON MAY 18 2015 .SYNOPSIS... WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON. && .NEAR TERM /THROUGH TUESDAY/... SCATTERED POPCORN CONVECTION IS BEING SEEN ACROSS THE AREA THIS AFTERNOON...AS MOIST AIRMASS HEATS UP IN BOUNDARY LAYER HEATING. OTHERWISE...SLIGHTLY MORE ORGANIZED CONVECTION NOTED OVER EASTERN KY AND SOUTHERN OH...AS WEAK VORT FEATURE APPROACHES FROM THE WEST. IT APPEARS THE LATEST RAP RUNS HAVE A FAIR HANDLE ON THE OVERALL MASS FIELDS AND THE PROGRESSION OF FEATURES ACROSS TONIGHT. USED A RATHER BROAD BRUSH APPROACH TO COVER POPS THIS AFTERNOON AND THIS EVENING. HAVE FRONT CROSSING LATE TONIGHT AND EARLY MORNING. SPEED UP TIMING SLIGHTLY...BY AN HOUR OR TWO...NOT MUCH TO REALLY MAKE A CHANGE TO THE OVERALL FORECAST. FOR TEMPS...WILL SEE A FEW DEGREES OF COOLING TUESDAY OVER TODAYS HIGHS AS COOLER AIRMASS MOVES IN...WITH DRYING OF THE ATMOSPHERIC COLUMN. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... ZONAL FLOW FOR THE SHORT TERM PART OF THE FORECAST SHOULD PROVIDE FOR A DRY FORECAST. DO HAVE SLIGHT CHANCE POPS WEDNESDAY NIGHT AS SEVERAL UPPER LEVEL DISTURBANCES MOVE ACROSS THE NORTHERN OHIO VALLEY AROUND THE 520+ LOW OVER NEWFOUNDLAND. WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD...KEEPING THEM BELOW CLIMATOLOGY. && .LONG TERM /FRIDAY THROUGH MONDAY/... A HIGH BEGINS TO BUILD IN THE GULF OF MEXICO ON SUNDAY...MIGRATES EAST AND TRIES TO STRENGTHEN. THIS WILL LEAD TO A POTENTIALLY MESSY FORECAST FOR THE OHIO VALLEY WITH SEVERAL UPPER LEVEL DISTURBANCES ROTATING AROUND THE CANADIAN LOW PRESSURE SYSTEMS. HAVE CHANCE POPS ON SUNDAY AND MONDAY AS EXPECT MOISTURE TO BECOME TRAPPED UNDER THE HIGH. THERE REALLY ISN/T ANYTHING SIGNIFICANT TO FOCUS ON TO TIME THESE EVENTS. WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. TEMPERATURES WILL RISE THROUGH THE EXTENDED PART OF THE FORECAST. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20 TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS. AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR. HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H M M H H H H H H HTS CONSISTENCY H H H H M H H H H H H H BKW CONSISTENCY H H M M M M M M M M M H EKN CONSISTENCY H H M M M M M M M M L L PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H M M M M M H H AFTER 18Z TUESDAY... FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. REDUCE VISIBILITY POSSIBLE IN AND AROUND THUNDERSTORMS NEXT SUNDAY AND MONDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...FB/KMC NEAR TERM...KMC SHORT TERM...FB LONG TERM...FB AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
236 PM EDT MON MAY 18 2015 .SYNOPSIS... WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON. && .NEAR TERM /THROUGH TUESDAY/... SCATTERED POPCORN CONVECTION IS BEING SEEN ACROSS THE AREA THIS AFTERNOON...AS MOIST AIRMASS HEATS UP IN BOUNDARY LAYER HEATING. OTHERWISE...SLIGHTLY MORE ORGANIZED CONVECTION NOTED OVER EASTERN KY AND SOUTHERN OH...AS WEAK VORT FEATURE APPROACHES FROM THE WEST. IT APPEARS THE LATEST RAP RUNS HAVE A FAIR HANDLE ON THE OVERALL MASS FIELDS AND THE PROGRESSION OF FEATURES ACROSS TONIGHT. USED A RATHER BROAD BRUSH APPROACH TO COVER POPS THIS AFTERNOON AND THIS EVENING. HAVE FRONT CROSSING LATE TONIGHT AND EARLY MORNING. SPEED UP TIMING SLIGHTLY...BY AN HOUR OR TWO...NOT MUCH TO REALLY MAKE A CHANGE TO THE OVERALL FORECAST. FOR TEMPS...WILL SEE A FEW DEGREES OF COOLING TUESDAY OVER TODAYS HIGHS AS COOLER AIRMASS MOVES IN...WITH DRYING OF THE ATMOSPHERIC COLUMN. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST. RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE FRONT STARTING TUESDAY NIGHT. DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST GIVING ZONAL FLOW FOR THE OHIO VALLEY. WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /THURSDAY THROUGH MONDAY/... NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY. WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20 TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS. AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR. HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H M M H H H H H H HTS CONSISTENCY H H H H M H H H H H H H BKW CONSISTENCY H H M M M M M M M M M H EKN CONSISTENCY H H M M M M M M M M L L PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H M M M M M H H AFTER 18Z TUESDAY... FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/ARJ NEAR TERM...KMC SHORT TERM...FB LONG TERM...FB AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
147 PM EDT MON MAY 18 2015 .SYNOPSIS... WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON. && .NEAR TERM /THROUGH TONIGHT/... NO UPDATES TO THE NEAR TERM OTHER THAN TO TWEAK POPS BASED ON CURRENT TRENDS. PREVIOUS DISCUSSION BELOW... LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING. LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA. MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT OF SHOWERS AND STORMS TODAY. LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND POOR DRAINAGE AREAS. WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE THE THREAT OF SHOWERS AND STORMS. CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST. RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE FRONT STARTING TUESDAY NIGHT. DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST GIVING ZONAL FLOW FOR THE OHIO VALLEY. WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /THURSDAY THROUGH SUNDAY/... NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY. WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20 TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS. AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR. HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H M M H H H H H H HTS CONSISTENCY H H H H M H H H H H H H BKW CONSISTENCY H H M M M M M M M M M H EKN CONSISTENCY H H M M M M M M M M L L PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H M M M M M H H AFTER 18Z TUESDAY... FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/ARJ NEAR TERM...JSH/KMC SHORT TERM...FB LONG TERM...FB AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
140 PM EDT MON MAY 18 2015 .SYNOPSIS... A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONVECTIVE DEVELOPMENT IS TAKING PLACE FROM NEAR SANDUSKY BAY SOUTHWEST TO NEAR FDY. WITH MODEST AMOUNT OF WIND SHEAR WE DON`T EXPECT MUCH IN THE WAY OF SEVERE POTENTIAL. DCAPE IS LOW GIVEN THE RATHER HUMID CONDITIONS WITH HIGH PRECIPITABLE WATER AMOUNT NEAR 1.6 INCHES. THE HRRR TIMING OF CONVECTIVE DEVELOPMENT IS SLOW BY A COUPLE OF HOURS. THE LATEST MESO ANALYSIS DATA SHOW LOW LEVEL CIN HAS DISSIPATED. EXPECT CONVECTIVE ACTIVITY TO INCREASE IN COVERAGE AND PROGRESS TO THE NORTHEAST. SHORT RANGE MESOSCALE MODELS SUGGEST THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL FORM OVER NORTHEAST OHIO ESPECIALLY IN THE SNOW BELT COUNTIES EAST OF CLE. GIVEN THE RATHER DEEP MOISTURE AND LIMITED SHEAR SEVERE POTENTIAL IS LOW. HAVE RAISED MAXIMUM TEMPERATURE JUST SLIGHTLY IN SPOTS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE INTO THE REGION. HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN. NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN COME TO SOME KIND OF CONSENSUS. UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT. THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH. OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S. YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY FROST THROUGH THE PERIOD AT THIS TIME. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND. SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST. MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... STILL WARM AND HUMID AHEAD OF A COLD FRONT THAT WILL BE CROSSING THE AREA THIS EVENING. SCATTERED SHOWERS HAVE BEEN ABLE TO POP UP ALREADY THIS AFTERNOON. ANY OF THESE COULD BRING CONDITIONS DOWN TO IFR/MVFR BRIEFLY. GAVE IT ANOTHER HOUR OR TWO BEFORE ANY THUNDER MENTIONED IN THE TAF. COLD FRONT LAGS UNTIL THIS EVENING AND THIS COULD BRING ANOTHER CHANCE FOR SHRA/TS. REALLY UNCERTAIN WHAT THE COVERAGE OF ANY TS MIGHT BE THEREFORE JUST WENT WITH VCSH WITH FROPA AND A PERIOD OF MVFR. POST FRONT EXPECT A RETURN TO VFR ALTHOUGH GIVEN TIMING...INLAND EAST WILL LIKELY HANG ON TO THE MVFR A BIT LONGER. VFR CU TUESDAY AND A NORTHWEST WIND...WITH ANY GUSTS 20 KNOTS OR LESS. .OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA TUESDAY NIGHT. && .MARINE... LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LAPLANTE SHORT TERM...LOMBARDY LONG TERM...TK AVIATION...OUDEMAN MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1242 PM EDT MON MAY 18 2015 .SYNOPSIS... A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONVECTIVE DEVELOPMENT IS TAKING PLACE FROM NEAR SANDUSKY BAY SOUTHWEST TO NEAR FDY. WITH MODEST AMOUNT OF WIND SHEAR WE DON`T EXPECT MUCH IN THE WAY OF SEVERE POTENTIAL. DCAPE IS LOW GIVEN THE RATHER HUMID CONDITIONS WITH HIGH PRECIPITAL WATER AMOUNT NEAR 1.6 INCHES. THE HRRR TIMING OF CONVECTIVE DEVELOPMENT IS SLOW BY A COUPLE OF HOURS. THE LATEST MESO ANAYLSIS DATA SHOW LOW LEVEL CIN HAS DISSIPATED. EXPECT CONVECTIVE ACTIVITY TO INCREASE IN COVERAGE AND PROGRESS TO THE NORTHEAST. SHORT RANGE MESOSCALE MODELS SUGGEST THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL FORM OVER NORTHEAST OHIO ESPECIALLY IN THE SNOW BELT COUNTIES EAST OF CLE. GIVEN THE RATHER DEEP MOISTURE AND LIMITED SHEAR SEVERE POTENTIAL IS LOW. HAVE RAISED MAXIMUM TEMPERATURE JUST SLIGHTLY IN SPOTS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE INTO THE REGION. HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN. NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN COME TO SOME KIND OF CONSENSUS. UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT. THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH. OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S. YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY FROST THROUGH THE PERIOD AT THIS TIME. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND. SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST. MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION. FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z. WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE FORECAST PERIOD REMAIN MVFR. .OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA TUESDAY NIGHT. && .MARINE... LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LAPLANTE SHORT TERM...LOMBARDY LONG TERM...TK AVIATION...TK MARINE...TK
AREA FORECAST DISCUSSION
NWS PORTLAND
249 PM PDT MON MAY 18 2015 .SYNOPSIS...ONSHORE FLOW RETURNS TONIGHT AND TUESDAY WITH PLENTY OF CLOUDS AND SOMEWHAT COOLER TEMPERATURES. THIS SHOULD RESULT IN GREATER STABILITY AND CONFINE THE THUNDERSTORM THREAT CLOSER TO THE CASCADE CREST TUESDAY WITH POTENTIAL TO SPREAD A LITTLE WESTWARD WEDNESDAY AND THURSDAY. TEMPERATURES SHOULD BE WITHIN A FEW DEGREES OF NORMAL FOR THE REMAINDER OF THE WEEK. && .SHORT TERM...TONIGHT THROUGH THURSDAY...DEEP CONVECTION AND THUNDERSTORMS HAVE DEVELOPED OVER THE CASCADES ABOUT ON SCHEDULE. THEY HAVE TAKEN ON A VERY SLIGHT WESTWARD DRIFT WHICH HAS ALLOWED THE STORMS A BIT OF LONGEVITY. STRONGEST ACTION HAS BEEN AROUND DETROIT WITH RADAR INDICATED RAIN RATES AS HIGH AS A COUPLE INCHES PER HOUR. THERE HAS BEEN ADDITIONAL FORMATION AROUND AND NORTH OF MT ST HELENS FORTUNATELY...THE WEAK MOVEMENT HAS LIMITED ACCUMULATIONS TO 0.75 TO 1.00 INCHES OVER AN HOUR. THE NORTHERN END OF THE CONVECTIVE LINE NEAR DETROIT HAS WEAKENED A BIT AS IT MOVED OVER THE EASTERN BOUNDARY OF THE FOOTHILL ZONE. LATEST HRRR RUNS STILL MAINTAIN A PRIMARY THREAT FOR THE STORMS TO CONTINUE OVER THE CASCADES THIS EVENING BUT IT WILL BE INTERESTING TO SEE HOW LONG THE VALLEY LASTS BEFORE STARTING CONVECTION. TEMPERATURES ONLY NEED TO RISE 4 TO 5 DEGREES BEFORE POTENTIALLY BREAKING THE 12Z SLE SOUNDING MID LEVEL CAP. STILL EXPECT STORMS WILL FORM...WHEREVER THEY DO...THROUGH THE EARLY EVENING BEFORE WEAKENING CONSIDERABLY WITH THE LOSS OF HEATING. THEN EXPECT SOME CONVECTIVE DEBRIS SHOWERS TO LINGER WEST ACROSS THE VALLEY BEFORE DISSIPATING AND DRIFTING INTO SOUTHWEST OREGON OVERNIGHT. THE VERY BROAD UPPER TROUGH WILL MOVE LITTLE WITH FAIRLY NON-DESCRIPT MID AND UPPER LEVEL FLOW PATTERNS REMAINING OVERHEAD MAKING TUESDAY THROUGH THURSDAY LARGELY A BROKEN RECORD. TUESDAY WILL SEE A BIT OF A COOL OFF FOR THE LOWER ELEVATIONS AS DEEPENING SURFACE LOW ACROSS THE COLUMBIA BASIN WILL EVENTUALLY DRAW THE MARINE LAYER BACK IN ACROSS THE LOWER ELEVATIONS. SEEMS UNLIKELY THE LAYER WILL BE SUBSTANTIALLY DEEP AND SHOULD SEE SOME AFTERNOON/EVENING CONVECTION ACROSS CASCADES ONCE AGAIN AND PROBABLY STAYING CLOSER TO THE CREST. WILL GET A LITTLE WARMER WEDNESDAY AND THURSDAY WITH A LITTLE BIT OF EASTERLY COMPONENT STORM MOTION TO AT LEAST BRING A THREAT OF THE HIGH CASCADE STORMS DRIFTING WEST TOWARD THE FOOTHILLS. MAY SEE SOME LIGHT SHOWER ACTIVITY OVER THE COAST RANGE AND VALLEY AS WELL. /JBONK .LONG TERM...THURSDAY NIGHT THROUGH MONDAY...PACIFIC NORTHWEST REMAINS UNDER LONGWAVE TROUGHING THROUGH THE WEEKEND INTO EARLY NEXT WEEK KEEPING WEATHER AND TEMPERATURES FAIRLY CONSISTENT. EXPECT AFTERNOON/EVENING SHOWERS IN THE CASCADES FRIDAY AND SATURDAY. FRIDAY MAY SEE SHOWERS SPILL WESTWARD INTO THE WILLAMETTE VALLEY...BUT CONFIDENCE IS LOW. HIGH PRESSURE ATTEMPTS TO BUILD ONSHORE SUNDAY...WHICH COULD PUSH MOST OF THE MOISTURE OFF TO THE EAST...THOUGH AS MODELS CONTINUE TO TREND WEAKER WITH THIS RIDGE SUNDAY IS LOOKING MORE LIKELY TO BE SIMILAR TO SATURDAY WITH SHOWERS IN THE CASCADES. MONDAY WILL SEE A RETURN TO THE PATTERN FAVORABLE FOR SHOWERS IN THE CASCADES. -MCCOY && .AVIATION...SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER THE CASCADES THIS AFTERNOON. THERE IS A CHANCE A FEW OF THESE THUNDERSTORMS WILL DRIFT WESTWARD AND IMPACT A WILLAMETTE VALLEY TAF SITE OR TWO LATER TODAY...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY. CONFIDENCE IN WHICH SITES WILL BE IMPACTED REMAINS LOW SO WILL KEEP A VCSH IN THE TAF FOR NOW. OTHERWISE...INCREASING ONSHORE PRESSURE GRADIENTS THIS AFTERNOON AND EVENING SHOULD RESULT IN MVFR STRATUS PUSHING BACK SOLIDLY ONTO THE COAST AND INTO THE COASTAL GAPS OVERNIGHT. THERE IS A GOOD CHANCE THESE LOWER FLIGHT CONDITIONS WILL IMPACT A FEW INTERIOR TAF SITES AS WELL. KPDX AND APPROACHES...SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER THE CASCADES THIS AFTERNOON AND WILL LIKELY IMPACT EASTERN APPROACHES. THERE IS A CHANCE A STORM COULD DRIFT WESTWARD AND IMPACT THE TERMINAL...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY...BUT CONFIDENCE IN THIS SCENARIO PANNING OUT REMAINS LOW. MVFR CONDITIONS SHOULD RETURN TO THE TERMINAL BETWEEN 12Z AND 18Z TUESDAY. /NEUMAN && .MARINE...SURFACE HIGH PRESSURE AND THERMAL LOW PRESSURE OVER THE INLAND NORTHWEST WILL MAINTAIN RELATIVELY LIGHT NORTHWESTERLY WINDS THROUGH THE UPCOMING WEEKEND. VERY STRONG EBBS WILL LIKELY PRODUCE STEEP EBB CHOP THE NEXT SEVERAL MORNINGS ON THE COLUMBIA RIVER BAR...BUT SEAS SHOULD REMAIN SMALL ENOUGH THAT SMALL CRAFT ADVISORIES FOR ROUGH BARS DO NOT APPEAR NECESSARY. /NEUMAN && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...NONE. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS MEDFORD OR
207 PM PDT MON MAY 18 2015 .SHORT TERM...MOISTURE CONTINUES TO ROTATE IN OVER OUR AREA FROM THE EAST AS AN UPPER LOW MOVES INTO THE GREAT BASIN. DYNAMICS ARE WEAK, BUT THERE IS PLENTY OF INSTABILITY PRESENT FROM THE CASCADE CREST AND SISKIYOUS EASTWARD, AND NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS HAVE ALREADY DEVELOPED. THIS CONVECTION WILL INCREASE IN COVERAGE AND MIGRATE TOWARD THE WEST THROUGH THE AFTERNOON. CONVECTION IS ALREADY TRYING TO SPILL OVER ONTO THE WEST SIDE, BUT IT IS BEING INHIBITED BY THE LITTLE REMAINING CAP. THE SUN IS PEAKING THROUGH IN THE WEST SIDE VALLEYS AND THE SURFACE HEATING WILL BREAK THE CAP PRETTY SOON. MESOANALYSIS INDICATES WE`VE BUILT 500-1000 J/KG OF SURFACE BASED CAPE OVER JACKSON AND JOSEPHINE COUNTIES ALREADY, WHICH SHOULD BE RELEASED EVENTUALLY, AND RESULT IN SHOWERS AND THUNDERSTORMS THERE AS WELL. LATEST RAP AND HRRR GUIDANCE ACTUALLY SHOWS QUITE A LOT OF CONVECTION OVER THE ROGUE AND ILLINOIS VALLEYS LATER THIS AFTERNOON. THEY MAY BE A BIT OVERDONE, BUT PEOPLE IN THESE AREAS SHOULD KEEP AN EYE ON THE SKY. AS OPPOSED TO YESTERDAY, THE SUN IS ALSO POKING OUT IN THE UMPQUA, AND THEY DO STAND A BETTER CHANCE OF SEEING SOME THUNDERSTORMS THIS AFTERNOON AS WELL. THERE IS A LOT OF MOISTURE IN THE PROFILE (PRECIPITABLE WATER IS NEAR AN INCH) AND THUS ANY OF THESE STORMS WILL BE CAPABLE OF PRODUCING SMALL HAIL AND HEAVY DOWNPOURS. WITH LITTLE WIND ALOFT TO SPEAK OF, STRONG WINDS SHOULDN`T BE MUCH OF A CONCERN, BUT WE COULD SEE GUSTY WINDS AROUND STORMS. THINGS WILL STABILIZE TONIGHT AS THE BOUNDARY LAYER COOLS, BUT SHOWERS ARE LIKELY TO CONTINUE OVERNIGHT ALONG THE MOUNTAINS AND EAST SIDE. AS BROAD TROUGHING REMAINS OVER THE REGION, WE EXPECT TO REPEAT THIS BASIC DIURNAL PATTERN OF NIGHT TIME SHOWERS AND MORE WIDESPREAD SHOWERS AND THUNDERSTORMS IN THE AFTERNOONS TOMORROW THROUGH THURSDAY. WE SHOULD GRADUALLY BECOME MORE STABLE ON THE WEST SIDE, SO THUNDERSTORMS BECOME LESS OF AN ISSUE. ONE BIGGER CHANGE I MADE WAS TO INCREASE POPS OVER THE WEST SIDE TUESDAY NIGHT INTO WEDNESDAY MORNING AS ALL THE MODELS ARE SHOWING A DEFORMATION BAND FORMING OVER THE AREA. -WRIGHT .LONG TERM...THE MODELS SHOW THE WEAK UPPER LOW MOVING INTO ARIZONA WITH WEAK RIDGING BUILDING OFFSHORE. THE GFS SHOWS MORE RIDGING COMPARED TO THE EC AND BOTH CONTINUE TO SHOW QPF OVER MOST OF THE AREA. I SUSPECT THE QPF MAY BE OVERDONE NOT ONLY WITH AMOUNTS, BUT ALSO THE COVERAGE. THUS HAVE SCALED BACK ON POPS FOR FRIDAY. ANOTHER WEAK UPPER LOW MOVES INTO THE AREA SATURDAY, BUT THIS ONE WILL BE COMING IN FROM THE NORTHWEST AND IS NOT EXPECTED TO HAVE ANY OVER WATER TRAJECTORY, THEREFORE MOISTURE WILL BE LIMITED AND ANY SHOWERS SHOULD BE ISOLATED AND EAST OF THE CASCADES. THE EC AND GFS DISAGREE WITH THE PROGRESSION OF THE UPPER LOW SUNDAY AND THE UPSTREAM UPPER LOW. THE GFS KEEPS THE UPPER LOW OVER THE AREA SUNDAY WHILE THE EC MOVES IT INTO NORTHERN CAL. FOR NOW WE`LL GO WITH A BLEND BETWEEN THE TWO AND KEEP A SLIGHT CHANCE OF SHOWERS EAST OF THE CASCADES. THE ENSEMBLE MEAN SHOWS A LARGE SPREAD IN THIS TIME PERIOD WHICH YIELDS LOWER CONFIDENCE IN THE FORECAST. -PETRUCELLI && .AVIATION...FOR THE 18/18Z TAF CYCLE...THE MAIN CONCERN INTO THIS EVENING WILL BE GUSTY AND ERRATIC WINDS NEAR THUNDERSTORMS. A FEW STORMS COULD ALSO PRODUCE SMALL HAIL. VFR CIGS WILL BE THE DOMINATE CONDITION INTO THIS EVENING FOR ALL TERMINALS, EXCEPT FOR TEMPORARY MVFR CIGS WITH PARTIAL MOUNTAIN OBSCURATION AND REDUCED VISIBILITY IN SHOWERS AND THUNDERSTORMS. THE ATMOSPHERE WILL STABILIZE TONIGHT AND CIGS WILL LOWER TO MVFR, THEN IFR AT THE COAST. MODELS ALSO SHOW PLENTY OF LOW LEVEL MOISTURE INLAND TONIGHT AND IT`S POSSIBLE MVFR CIGS WILL ALSO DEVELOP FOR INLAND LOCATIONS BETWEEN 4-6Z WITH LOCAL IFR CIGS IN THE UMPQUA BASIN LATE TONIGHT. -PETRUCELLI && .MARINE...UPDATED 200 PM PDT, MONDAY 18 MAY 2015...A PATTERN OF WEAK HIGH PRESSURE OFFSHORE AND WEAK LOW PRESSURE INLAND WILL PERSIST MOST OF THIS WEEK WITH LIGHT TO MODERATE NORTH WINDS AND NORTHWEST SWELL OVER THE WATERS. WINDS WILL APPROACH SMALL CRAFT ADVISORY LEVELS ON TUESDAY EVENING AND WEDNESDAY MORNING SOUTH OF CAPE BLANCO. AFTER THIS NORTH WINDS AROUND 10-20 KTS WILL CONTINUE INTO THE WEEKEND. /CS && .FIRE WEATHER...UPDATED 200 PM PDT, MONDAY 18 MAY 2015...AN UPPER LOW CENTERED JUST EAST OF THE BAY AREA IS SENDING MOISTURE NORTHEAST TOWARDS THE AREA. SO FAR ISOLATED STORMS HAVE BEEN CONFINED TO THE CASCADES EAST, BUT THEY ARE EXPECTED TO BECOME MORE FREQUENT AS THE AFTERNOON PROGRESSES INTO THIS EVENING. THE LATEST MESOSCALE ANALYSIS SHOWS HIGHER CAPE VALUES WEST OF THE CASCADES COMPARED TO YESTERDAY AND THE MOIST LAYER IS MUCH DEEPER ALL THE WAY UP TO 400 MB BASED IN THIS MORNINGS SOUNDING. THE 700 MB FLOW WILL BE FROM THE EAST TO NORTHEAST, THERE IS A BETTER CHANCE FOR SHOWERS AND ISOLATED STORMS TO MAKE THEIR WAY WEST OF THE CASCADES. WITH PLENTY OF MOISTURE AVAILABLE, THUNDERSTORMS ARE LIKELY TO BE RAIN PRODUCERS AND THEY WILL BE SLOW MOVERS. SO HEAVY RAINFALL IS POSSIBLE. THUNDERSTORMS WILL DECREASE THIS EVENING AND END TONIGHT, BUT WE`LL CONTINUE TO GET MUCH NEEDED RAIN SHOWERS OVERNIGHT TONIGHT. THE UPPER LOW WILL MOVE EAST AND WEAKEN TUESDAY WITH THE BEST CHANCE FOR THUNDERSTORMS ALONG AND EAST OF THE CASCADES. THE ATMOSPHERE IS EXPECTED TO BE MORE STABLE WEST OF THE CASCADES DUE TO A MARINE INFLUENCE, SO WERE ONLY EXPECTING SHOWERS. -PETRUCELLI && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PACIFIC COASTAL WATERS...NONE. $$
AREA FORECAST DISCUSSION
NWS PORTLAND
942 AM PDT MON MAY 18 2015 .SYNOPSIS...BROAD BUT ILL-DEFINED UPPER LEVEL LOW PRESSURE WILL REMAIN OVER MUCH OF THE WESTERN UNITED STATES THE NEXT SEVERAL DAYS...KEEPING THE WEATHER UNSETTLED IN GENERAL ACROSS THE REGION. WEAK HIGH PRESSURE OVER EASTERN WASHINGTON HAS WEAKENED ONSHORE FLOW CONSIDERABLY. WITHOUT THE STRONG MARINE INFLUENCE...TEMPERATURES WILL BE A FEW DEGREES WARMER INLAND THAN THE PAST FEW DAYS. THIS WILL DESTABILIZE THE ATMOSPHERE TO THE POINT WHERE THUNDERSTORMS COULD DEVELOP FROM THE COAST RANGE EASTWARD THIS AFTERNOON AND EVENING. THE OVERALL AIR MASS IS RATHER MOIST AND STORMS WILL BE SLOW MOVING...SO THE POTENTIAL IS THERE FOR LOCALLY HEAVY RAIN. ONSHORE FLOW RETURNS IN FULL FORCE TONIGHT AND TUESDAY WITH PLENTY OF CLOUDS AND A RETURN TO COOLER TEMPERATURES. THIS SHOULD RESULT IN GREATER STABILITY AND CONFINE THE THUNDERSTORM THREAT TO AREAS ALONG AND EAST OF THE CASCADE CREST FOR MUCH OF THE WEEK. AFTER TODAY...TEMPERATURES SHOULD BE WITHIN A FEW DEGREES OF NORMAL FOR THE REMAINDER OF THE WEEK. && .UPDATE...SOME CHANGES TO THE FORECAST PACKAGE FOR TODAY AND TONIGHT...BUT THE OVERALL MESSAGE WILL BE THE SAME. 12Z SALEM SOUNDING SHOWED A LITTLE STRONGER MID LEVEL CAP WITH TEMPERATURES FEW DEGREES WARMER THAN THE EARLIER MODEL RUNS INDICATED. LOOKS LIKE THE 12Z NAM/GFS AND LAST COUPLE HRRR RUNS PICKED UP ON THIS AND HAVE SOMEWHAT DIMINISHED THE THUNDER THREAT FROM THE WILLAMETTE VALLEY/PORTLAND METRO AND AREAS WEST. FORECASTED HIGH TEMPS TODAY WILL STILL BE AROUND THE CONVECTIVE TEMPS SO CONTINUE TO EXPECT A THUNDERSTORM ALONG THE I-5 CORRIDOR AND WILL LIMIT COVERAGE TO ISOLATED. THE CASCADES AND FOOTHILLS STILL APPEAR TO HAVE THE FAR BETTER CHANCE OF SEEING SCATTERED COVERAGE WITH THE HIGHER TERRAIN ACTING AS THE ELEVATED HEAT SOURCE. THAT WILL MAKE IT EASIER TO BREAK THROUGH THAT CAP. THE BIG UNKNOWN WILL BE THE AMOUNT OF STORM MOTION. MODELED STORM MOTIONS FOR YESTERDAY PRODUCED NORTHERLY DRIFT OF AROUND 5 KTS WHICH WAS JUST ENOUGH TO KEEP THE DOWNDRAFT AWAY FROM THE UPDRAFT AND GIVE SOME LONGEVITY TO THE CELLS. MODELED STORM MOTIONS FOR TODAY BROADLY SHOW ZERO MOVEMENT ACROSS THE AREA. MENTAL MODEL OF THIS PROVIDES FOR MORE OF A PULSE STORM SITUATION WHERE STORMS MAY PUT OUR A BRIEF HEAVY RAIN AND SEVERAL LIGHTNING STRIKES BUT THEN COLLAPSE AS THE UPDRAFT IS CUT OFF BY THE DOWNDRAFT. ENVISION SOMETHING LIKE AN OLD SCHOOL PINBALL MACHINE EFFECT WHERE COLLIDING OUTFLOW BOUNDARIES CONVERGE TO PRODUCE A NEW UPDRAFT AS A TRIGGER FOR A NEW CELL. THUNDERSTORM INITIATION TIMING STILL FAVORS EARLY AFTERNOON FOR THE CASCADES AND FOOTHILLS WITH IT TAKING UNTIL MID TO LATE AFTERNOON FOR THE I-5 CORRIDOR. GIVEN THIS WILL BE MORE OF AN AIR MASS THUNDERSTORM DAY WHERE GROUND HEATING IS THE TRIGGER...FEEL MOST DEEP CONVECTIVE ACTION SHOULD QUICKLY DIMINISH TOWARDS THE 7 TO 8 PM HOURS WITH WEAKER NON-THUNDERSTORM SHOWERS CONTINUING TOWARD MIDNIGHT. LINGERING CONVECTIVE DEBRIS SHOWERS MAY ULTIMATELY HANG ON AFTER MIDNIGHT BUT MAINLY CLOSER TO LANE COUNTY. UPDATES SHOULD BE AVAILABLE NOW. /JBONK && .AVIATION...MARINE STRATUS IS CURRENTLY PRODUCING HIGH END IFR TO LOW MVFR CONDITIONS ALONG THE COAST AND ALONG THE COLUMBIA RIVER. EXPECT INTERIOR LOCATIONS TO TURN VFR BETWEEN 17Z AND 18Z TODAY. CONFIDENCE IN TIMING STRATUS BREAKUP ALONG THE COAST IS LOWER...BUT BASED ON SATELLITE AND MODEL GUIDANCE IT APPEARS VFR CONDITIONS WILL BE LONGER LIVED AT KONP THAN KAST TODAY. SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP OVER THE CASCADES THIS AFTERNOON. THERE IS A CHANCE A FEW THUNDERSTORMS WILL DRIFT WESTWARD AND IMPACT A WILLAMETTE VALLEY TAF SITE OR TWO LATER TODAY...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY...BUT LATEST MODEL GUIDANCE HAS BACKED OFF ON THIS IDEA A BIT. AS A RESULT...CONFIDENCE IN DETAILS REMAINS LOW AND WILL KEEP A VCSH IN THE TAFS FOR NOW. OTHERWISE...HEALTHY ONSHORE FLOW THIS AFTERNOON AND EVENING SHOULD RESULT IN MVFR STRATUS PUSHING BACK SOLIDLY ONTO THE COAST AND INTO THE COASTAL GAPS OVERNIGHT. THERE IS A GOOD CHANCE THESE LOWER FLIGHT CONDITIONS WILL IMPACT AT LEAST KPDX AND KTTD BY 15Z TUESDAY. KPDX AND APPROACHES...TEMPORARY LOW END MVFR CONDITIONS CURRENTLY AT THE TERMINAL WILL END BETWEEN 17Z AND 18Z MONDAY. SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP OVER THE CASCADES LATER TODAY AND COULD DRIFT WESTWARD AND IMPACT THE TERMINAL...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY...BUT CONFIDENCE IN THIS SCENARIO REMAINS LOW. MVFR CONDITIONS SHOULD RETURN TO THE TERMINAL BETWEEN 12Z AND 18Z TUESDAY AS MARINE STRATUS PUSHES UP THE COLUMBIA RIVER. /NEUMAN && .MARINE...SURFACE HIGH PRESSURE AND THERMAL LOW PRESSURE OVER THE INLAND NORTHWEST WILL MAINTAIN RELATIVELY LIGHT NORTHWESTERLY WINDS THROUGH THE UPCOMING WEEKEND. A WEAK UPPER LEVEL LOW PRESSURE SYSTEM MAY TEMPORARILY SHIFT WINDS OUT OF THE SOUTH OVER THE WEEKEND...BUT IMPACTS TO WIND SPEEDS APPEAR NEGLIGIBLE. VERY STRONG EBBS WILL LIKELY PRODUCE STEEP EBB CHOP THE NEXT SEVERAL MORNINGS ON THE COLUMBIA RIVER BAR...BUT SEAS SHOULD REMAIN SMALL ENOUGH THAT SMALL CRAFT ADVISORIES FOR ROUGH BARS DO NOT APPEAR NECESSARY. /NEUMAN && .PREV DISCUSSION... /ISSUED 307 AM PDT MON MAY 18 2015/ SHORT TERM...TODAY THROUGH WEDNESDAY...AS ADVERTISED FOR SEVERAL DAYS NOW...TODAY CONTINUES TO BE THE BEST THREAT IN QUITE SOME TIME FOR SEVERAL NON-SEVERE THUNDERSTORMS TO DEVELOP COAST RANGE EASTWARD. MAIN THREAT FROM THESE STORMS WILL BE LOCALLY HEAVY RAIN AND POSSIBLY SMALL HAIL. SOME HIGHLY LOCALIZED AND BRIEF URBAN AND SMALL STREAM FLOODING ISSUES ARE POSSIBLE IF ANY OF THESE STORMS DEVELOP OVER POOR DRAINAGE AREAS...ESPECIALLY IF THEY MOVE THROUGH THE DENSER URBAN AREAS. TODAY WILL BE AN INTERESTING DAY TO WATCH THE RADAR ACROSS WESTERN OREGON...AND POSSIBLY SOUTHWEST WASHINGTON. THE INGREDIENTS COMING TOGETHER TODAY TO SUPPORT DEEP CONVECTION AND THUNDERSTORMS...1. WEAK HIGH PRESSURE OVER EASTERN WASHINGTON HAS WEAKENED ONSHORE FLOW ACROSS THE FORECAST AREA...LIMITING THE STABILIZING MARINE INFLUENCE TO MAINLY THE COASTAL AREAS. THIS WILL CAUSE INLAND TEMPS TO WARM THROUGH THE 70S...POSSIBLY EVEN UPPER 70S IN THE PORTLAND METRO AREA. 2. SKIES HAVE GENERALLY CLEARED ACROSS THE FORECAST AREA ASIDE FROM SOME THIN HIGH CLOUDS. THIS SHOULD REMAIN THE CASE FOR THE FIRST HALF OF THE DAY. THIS WILL ALSO HELP SFC TEMPS REACH THE CONVECTIVE TEMPS INDICATED ON MODEL SOUNDINGS COAST RANGE EASTWARD. 3. NAM/GFS BUFR SOUNDINGS AGREE THAT THERE WILL BE LITTLE TO NO CAP IN THE ATMOSPHERE UP TO THE TROPOPAUSE. IF SURFACE TEMPS CAN REACH THE CONVECTIVE TEMP OF AROUND 75 DEG F... THERE IS LITTLE TO STOP PARCELS FROM REACHING THE TROPOPAUSE. DEEP BUT FAIRLY SKINNY SBCAPE ON THE ORDER OF 750-1500 J/KG IS BEING SHOWN UP AND DOWN THE WILLAMETTE VALLEY AND CASCADES THIS AFTERNOON WITH LIFTED INDICES OF -1 TO -4 DEG C. AS A RESULT...EQUILIBRIUM LEVELS ARE 30-35 KFT...PLENTY DEEP FOR CHARGE SEPARATION AND LIGHTNING TO DEVELOP. AS USUAL FOR OUR AREA...THERE ARE AT LEAST A COUPLE CONS FOR THUNDER TODAY...AT LEAST FOR AREAS WILLAMETTE VALLEY EASTWARD... 1. MODELS ARE ALREADY OVERESTIMATING THE SFC DEWPOINTS...FORECASTING LOWER 50S THIS MORNING WHILE DEWPOINTS ARE ACTUALLY IN THE MID TO UPPER 40S. IF THIS TREND HOLDS...MODEL CAPE/LI VALUES WILL LIKELY BE EXAGGERATED. 2. LITTLE TO NO SHEAR. UPDRAFTS MAY QUICKLY BE OVERWHELMED BY DOWNDRAFTS...POSSIBLY BEFORE THUNDERSTORMS CAN MATURE. 3. WEAK FORCING. WITH LITTLE FLOW IN OUR VERY BROAD UPPER LEVEL LOW...VORTICITY IS HARD TO COME BY. EXPECT VERY LITTLE HELP FROM ANY SYNOPTIC FEATURES TODAY...DESPITE A WEAK SHORTWAVE DRIFTING WEST ACROSS THE SOUTHERN PORTION OF OUR CWA. GIVEN THE CONVECTION WHICH DEVELOPED IN THE CASCADES SUNDAY IN A LESS FAVORABLE ENVIRONMENT...CONFIDENCE IS HIGHER THAN USUAL THAT SCATTERED THUNDERSTORMS WILL DEVELOP ALONG THE CASCADES TODAY. THE SAME ENVIRONMENT FAVORING THUNDER IN THE CASCADES TODAY SHOULD SUPPORT SCATTERED THUNDERSTORMS POPPING OFF IN THE WILLAMETTE VALLEY BY MID-AFTERNOON...ASSUMING DEBRIS FROM THE EARLIER CASCADE THUNDERSTORMS DO NOT LIMIT SFC HEATING TOO MUCH. ADDITIONALLY SPC SREF CALIBRATED THUNDERSTORM PROBABILITY IS 50-60 PCT ACROSS PORTIONS OF OUR INTERIOR LOWLANDS...THE HIGHEST I HAVE SEEN IT. THEREFORE WE ADDED SCATTERED THUNDERSTORM WORDING TO ALL AREAS COAST RANGE EASTWARD. GIVEN THE WEAK SHEAR ENVIRONMENT...IT IS DOUBTFUL ANY THUNDERSTORMS WILL REACH SEVERE LIMITS. MOST CELLS SHOULD BE PULSE-LIKE...ONLY LASTING FOR A SHORT PERIOD OF TIME WITH LITTLE ORGANIZATION. HOWEVER WITH PRECIPITABLE WATER VALUES APPROACHING 1 INCH AND VERY WEAK STEERING FLOW...THERE IS THE POTENTIAL FOR RAINFALL HEAVY ENOUGH TO CAUSE BRIEF AND LOCALIZED URBAN/SMALL STREAM FLOODING ISSUES. SOME LOCATIONS WILL RECEIVE NO RAIN AT ALL...WHILE SOME MAY SEE UPWARDS OF A HALF INCH OF RAIN IN A VERY SHORT PERIOD OF TIME. HIGHLIGHTED THIS THREAT IN THE GRIDS AND WILL ISSUE A SPECIAL WEATHER STATEMENT MENTIONING THIS POSSIBILITY FOR THE AFTERNOON/EVENING COMMUTE. MEANWHILE SEMI-THERMALLY INDUCED LOW PRESSURE WILL DEVELOP OVER THE COLUMBIA BASIN THIS AFTERNOON...INCREASING THE ONSHORE COMPONENT OF THE LOW LEVEL FLOW. THIS SHOULD CAUSE A SURGE OF MARINE AIR TONIGHT WHICH WILL CUT OFF THE THUNDERSTORM THREAT AND YIELD A MOSTLY CLOUDY...COOLER DAY TUESDAY. TUESDAY HAS SOME POTENTIAL TO BE A LOT LIKE LAST FRI/SAT...SO DECIDED TO UNDERCUT MOS GUIDANCE BY A FEW DEGREES FOR HIGH TEMPS. THE STABLE MARINE AIR WILL LIKELY CONFINE ANY THUNDERSTORMS TO AREAS ALONG AND EAST OF THE CASCADE CREST. WEDNESDAY IS A BIT OF A TOUGH TEMPERATURE FORECAST AS MODELS SHOW GOOD AGREEMENT ON HIGHS ONCE AGAIN REACHING THE MID-UPPER 70S FOR THE INLAND VALLEYS DESPITE CONTINUED ONSHORE PRESSURE GRADIENTS. THE MARINE LAYER APPEARS A BIT SHALLOWER THAN IT WAS FRI/SAT...SO THERE IS BETTER CHANCE OF IT MIXING OUT FOR THE AFTERNOON. NONETHELESS WE DECIDED TO KEEP FCST TEMPS ON THE LOW SIDE OF GUIDANCE FOR WEDNESDAY. THE SHALLOWER MARINE LAYER MAY LEAD TO A BETTER CHANCE OF THUNDER IN THE CASCADES WED AFTN/EVE...ESPECIALLY WITH SOME MODELS SUGGESTING ANOTHER WEAK SHORTWAVE PIVOTING WESTWARD ACROSS OREGON AT THAT TIME. WEAGLE LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... WEDNESDAY NIGHT THROUGH SUNDAY...BROAD UPPER-LEVEL TROUGHING REMAINS IN PLACE THROUGH THE END OF WEEK...WITH SHORTWAVES BRINGING CHANCES OF RAIN THURSDAY AND FRIDAY AND MAYBE SOME THUNDERSTORMS IN THE CASCADES. RIDGING SHOWN YESTERDAY IN MODELS FOR THE WEEKEND IS LOOKING WEAKER...AND LIKELY WON`T PULL US OUT OF THE OVERALL LONGWAVE TROUGH PATTERN. THAT SAID...WITH WEAK HIGH PRESSURE OVER THE REGION SATURDAY AND SUNDAY WEATHER COULD DRY OUT FOR THE WEEKEND WITH MOSTLY SUNNY SKIES. CONFIDENCE IS STILL LOW AS OF NOW DUE TO HOW FAR OUT IN THE FORECAST PERIOD THIS IS AS WELL AS THE WEAKENING TREND IN THE MODELS. -MCCOY && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...NONE. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
657 PM EDT MON MAY 18 2015 .SYNOPSIS... A COLD FRONT WILL PUSH ACROSS THE AREA TONIGHT AND EARLY TUESDAY...PRECEDED BY SHOWERS AND THUNDERSTORMS. THE FRONT WILL USHER IN A COOL...DRY AIRMASS FOR THE MIDDLE OF THE WEEK. MUGGINESS WILL RETURN OVER THE HOLIDAY WEEKEND. && .NEAR TERM /UNTIL 1 AM TUESDAY MORNING/... VERY HIGH PWAT AIR SITTING OVER THE AREA. CAPE HAS BEEN SOMEWHAT LIMITED UNTIL THE LAST 30 TO 60 MINUTES. THE CAP IS BROKEN AND TC HAS BEEN PASSED. SHOWERS AND THUNDERSTORMS HAVE GROWN OVER ALMOST ALL OF THE CWA WITH LITTLE TO NO PATTERN OR ORGANIZATION. THERE HAS BEEN ONE BACK-BUILDING STORM IN SRN LANC CO. BUT THE HIGH MOISTURE WILL TIELD SOME VERY HIGH RAIN RATES. WILL NEED TO KEEP AN EYE ON AREAS WHICH RECEIVE MULTIPLE STORMS/BACKBUILD. THESE SHOWERS WILL CONTINUE INTO THE EVENING. LATEST NAM RUN PUSHES MOST OF THE RAIN OFF TO THE EAST OF THE SUSQ RIVER SHORTLY AFTER 1 AM. && .SHORT TERM /1 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... THE FIRST NUDGE OF DRY AIR COMES IN UNDER A SHORT WAVE CURRENTLY OVER KCVG. THIS SHOULD EFFECTIVELY END MOST OF THE SHOWERS. BUT THE REAL COLD/DRY AIR DOES NOT ARRIVE IN THE WEST UNTIL CLOSE TO SUNRISE TUES. THUS...A SLIGHT CHC OF A SHOWER WILL BE MENTIONED FOR MUCH OF THE AREA OVERNIGHT - ESP IN THE EAST. DEWPOINTS DROP THROUGH THE DAY IN THE NW HALF OF THE AREA...BUT THE SE COULD STAY MUGGY AND THE SKY SHOULD BREAK UP LATER TONIGHT. SO SUNSHINE WILL HEAT UP THE ERN VALLEYS. A STORM OR TWO WILL PROBABLY POP UP IN THE HEATING OF THE DAY THERE...BUT ARRIVAL OF THE DRY AIR WILL MAKE IT DIFFICULT TO ALLOW ANYTHING TO GROW ENOUGH IN THE WEST TO PRECIPITATE. FOG AND LOW CLOUDS ARE AGAIN EXPECTED OVER MOST/ALL OF THE AREA. PERHAPS ONLY THE PLACES WHICH CAN KEEP WIND OVER 5-6KTS THROUGH THE NIGHT - MAINLY HIGHER ELEVS IN THE WEST - CAN STAY AWAY FROM BAD VISBYS. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... AREA OF SHOWERS/TSTMS WILL BE DEPARTING LATE TUE/EARLY TUE EVE...ASSOCIATED WITH A COLD FRONT CLEARING THE REGION. IN IT/S WAKE...RESPECTABLE ANTICYCLONE WILL BUILD IN FROM THE WEST WITH A PUSH OF NOTICEABLY COOLER AND DRIER AIR FILTERING IN FOR MIDWEEK. A WEAK WAVE EJECTS EASTWARD FROM THE S PLAINS TOWARD THE CAROLINA/S ON THU...WHILE TROUGH CONTINUES TO SPIN OVER EASTERN CANADA. CENTRAL PA REMAINS BETWEEN THESE TWO FEATURES...WHICH WILL KEEP US DRY. EVEN WITH NW FLOW...DAYTIME TEMPS WILL REBOUND A BIT WARMER EACH DAY. BUT DIURNAL TEMP RANGES WILL BE FAIRLY LARGE THANKS TO THE DRIER AIRMASS...WHICH WILL BRING CHILLY MORNINGS. THE COLDEST CONTINUES TO LOOK LIKE THURSDAY MORNING WHERE THERE REMAINS A RISK FOR PATCHY FROST...MAINLY OVER THE NORTH-CENTRAL ZONES WHERE GUIDANCE IS SHOWING POSS FOR MID 30S AOA BFD /JUST IN TIME FOR THE START OF THE GROWING SEASON/. THE WEAK LOW OVER CAROLINAS/MID ATLANTIC REGION SLIDES OFFSHORE FRI...WITH SPRAWLING HIGH PRESSURE AREA BUILDING IN FOR SAT/SUN. ONCE RIDGE AXIS SLIDES BY SAT NIGHT...HUMIDITY WILL BEGIN TO INCREASE ON SUNDAY WITH RISING TEMPS /AND ISOLATED CONVECTION POSS/. EVEN WARMER AND MUGGIER ON MEMORIAL DAY...WITH SCATTERED TO EVEN NUMEROUS SHOWERS/TSTMS IN THE FORECAST. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... SCT SHRA/TSRA WILL CONTINUE TO FORM ACROSS CENTRAL PA THIS EVENING IN UNSTABLE AIR MASS AHEAD OF APPROACHING COLD FRONT OVR THE MIDWEST. ANY OF THESE SHRA/TSRA COULD PRODUCE BRIEF VIS REDUCTIONS. HOWEVER...THE MAIN AVIATION CONCERN THIS EVENING WILL BE THE DEVELOPING LOW CIGS ACROSS EASTERN PA...THE RESULT OF MARINE AIR FLOWING OFF THE ATLANTIC OCEAN. LOWER CIGS ALREADY NOTED ACROSS NJ AT 22Z AND NEAR TERM MDL DATA SUPPORT IFR CIGS MOVING INTO KLNS/KMDT BTWN 00Z-02Z. THE IFR MARINE STRATUS DECK COULD WORK AS FAR WEST AS KIPT OVERNIGHT. FURTHER WEST...EXPECT IFR CIGS TO DEVELOP AFTER 06Z AT KBFD/KJST...WHERE A PLUME OF MOISTURE AHEAD OF COLD FRONT WILL ASCEND THE ALLEGHENY MTNS...PRODUCING THE LOW CIGS. BOTH SREF AND LATEST HRRR SUPPORT THIS SCENARIO. MOST FAVORABLE CONDS SHOULD BE AT KAOO/KUNV OVERNIGHT...WHERE SIG REDUCTIONS APPEAR UNLIKELY. LOW CIGS ACROSS THE W MTNS AND EASTERN PA SHOULD LIFT BY LATE AM. CAN/T RULE OUT AN ISOLD SHRA/TSRA ACROSS EASTERN PA ARND MIDDAY WITH PASSAGE OF COLD FRONT. OTHERWISE...EXPECT A RETURN TO WIDESPREAD VFR CONDS...AS A MUCH DRIER WEST WIND FLOWS IN BEHIND THE COLD FRONT. OUTLOOK... WED-SAT...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...RXR AVIATION...DANGELO/FITZGERALD
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
118 PM CDT MON MAY 18 2015 .UPDATE... UPDATED FOR 18Z AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 1100 AM CDT MON MAY 18 2015/ DISCUSSION... THE MCS THAT MOVED THROUGH OVERNIGHT HAS STABILIZED MUCH OF THE MIDSOUTH AND THE MAIN FOCUS FOR HEAVY RAIN HAS SHIFTED SOUTH OF THE AREA. LATEST HRRR INDICATES THAT SCT REDEVELOPMENT WILL OCCUR THIS AFTERNOON AS AIRMASS TRIES TO DESTABILIZE AGAIN DUE TO SURFACE HEATING BUT COVERAGE WILL BE LIMITED AND THE WIDESPREAD HEAVY RAIN THREAT HAS DIMINISHED. AS A RESULT DECIDED TO CANCEL FLASH FLOOD WATCH EARLY. SJM PREV DISCUSSION... /ISSUED 422 AM CDT MON MAY 18 2015/ A WEAKENING MESOSCALE CONVECTIVE SYSTEM (MCS) WAS LOCATED ALONG THE TN RIVER OF WEST TN INTO NORTHEAST MS EARLY THIS MORNING. THE MCS WAS PUSHING TO THE NORTHEAST. ANOTHER MCS WAS STRENGTHENING OVER NORTH LA AND LOOKS LIKE IT MIGHT SKIRT SOUTHERN PORTIONS OF NORTH MS WITH THE POSSIBILITY OF VERY HEAVY RAINFALL. WITH THE HEAVIER STORMS EARLIER TONIGHT ACROSS NORTH MS...VERY HEAVY RAINFALL WAS INDICATED IN SOME SPOTS...IN EXCESS OF 2 INCHES PLUS PER HOUR AS SHOWN BY DUAL POL RADAR. WILL KEEP THE FLASH FLOOD WATCH GOING FOR TODAY. LATEST MODELS DID COME IN WITH POPS A LITTLE LOWER FOR TODAY ESPECIALLY ACROSS AREAS TO THE NORTHWEST INCLUDING NORTHEAST AR AND THE MO BOOTHEEL. ALSO...MODELS ARE SHOWING PRECIPITABLE WATER VALUES DECREASING SLIGHTLY FROM THE NORTHWEST DURING THE DAY. NEVERTHELESS...A COLD FRONT WILL APPROACH THE REGION FROM THE NORTH TODAY MOVING INTO NORTHEAST AR LATE THIS AFTERNOON OR EARLY EVENING. INSTABILITY WILL INCREASE ACROSS THE AREA ALLOWING FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT. PRECIPITABLE WATER VALUES WILL BE BETWEEN 1.5 AND 2.1 INCHES ACROSS MOST OF THE AREA. WITH STORMS BEING VERY EFFICIENT RAIN PRODUCERS...THINK LOCALLY HEAVY RAINFALL COULD STILL BE A PROBLEM LEADING TO FLASH FLOODING. ALSO... THINK INSTABILITY WILL BE SUFFICIENT TO SUPPORT A FEW STRONG THUNDERSTORMS WITH STRONG GUSTY WINDS AND SMALL HAIL. THE COLD FRONT IS FORECAST TO MOVE THROUGH THE MIDSOUTH TONIGHT AND TUESDAY...ALTHOUGH THE NAM AND ECWMF ARE SLOWER WITH THE PASSAGE OF THE FRONT THAN THE GFS. THINK THE CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY WILL BE MAINLY ACROSS EAST CENTRAL AR INTO PORTIONS OF NORTH MS. DRIER AND A LITTLE COOLER AIR WILL SPREAD INTO THE REGION NORTH OF THE FRONT. THUS MUCH OF THE REGION WILL HAVE A VERY NICE SPRING DAY TUESDAY. FOR TUESDAY NIGHT INTO THURSDAY...FOLLOWED THE ECMWF / NAM SOLUTION VERSUS THE GFS. THE ECMWF AND NAM INDICATE THAT THE FRONTAL SYSTEM WILL PUSH BACK TO NORTH TUESDAY NIGHT WITH THE MIDSOUTH ONCE AGAIN IN THE WARM SECTOR WEDNESDAY. SURFACE HIGH PRESSURE WILL THEN PUSH THE FRONT BACK THROUGH THE REGION WEDNESDAY NIGHT AS A COLD FRONT. THIS WOULD RESULT IN ANOTHER THREAT OF HEAVY RAINFALL AND POSSIBLY A FEW STRONG TO SEVERE THUNDERSTORMS WEDNESDAY. HOWEVER...CONFIDENCE IS LOW AND DID NOT MENTION IN THE HAZARDOUS WEATHER OUTLOOK WITH THE GFS KEEPING THE FRONTAL SYSTEM MORE TO OUR SOUTH AND MOST OF OUR FORECAST AREA NOT GETTING BACK INTO THE WARM SECTOR. MODELS DO AGREE THAT DURING THE DAY THURSDAY DRIER AND A LITTLE COOLER AIR WILL SPREAD IN FROM THE NORTH ENCOMPASSING THE ENTIRE AREA BY THURSDAY NIGHT. PLEASANT AND DRY SPRING WEATHER WILL OCCUR FRIDAY AND FOR MOST OF THE AREA SATURDAY. ANOTHER LARGE SCALE UPPER LEVEL TROUGH WILL APPROACH FROM THE WEST BY THE LATTER HALF OF THE WEEKEND BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS...BUT ONCE AGAIN AS OBSERVED MUCH OF THIS SPRING...THE TROUGH IS FORECAST TO LIFT TO THE NORTHEAST AS STRONG UPPER LEVEL HIGH PRESSURE IS LOCATED ALONG THE SOUTHEASTERN UNITED STATES COAST. JCL .AVIATION... 18Z TAFS VFR..MVFR...AND POSSIBLY IFR CONDITIONS ARE EXPECTED THROUGHOUT THE 24 HR TAF CYCLE. SCATTERED SHOWERS AND THUNDERSTORMS HAVE STARTED TO FORM NEAR ALL FOUR TAF SITES THIS AFTERNOON. COVERAGE WILL CONTINUE TO INCREASE THROUGHOUT THE EVENING AND THUNDERSTORMS COULD DEVELOP AS THE ATMOSPHERE CONTINUES TO DESTABILIZE... HOWEVER WE WILL NOT SEE COVERAGE LIKE YESTERDAY. CIGS WILL REMAIN MVFR AND VFR THIS AFTERNOON BEFORE LIFTING AND CLEARING TO VFR LEVELS OVERNIGHT AT ALL SITES EXCEPT KTUP. FROPA WILL CAUSE WINDS TO SHIFT TO THE NORTH AROUND MIDNIGHT FOR KJBR...KMEM...AND KMKL. IFR CONDITIONS WILL BE POSSIBLE AT KTUP OVERNIGHT AND TOMORROW MORNING. JPM3 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1100 AM CDT MON MAY 18 2015 .DISCUSSION... THE MCS THAT MOVED THROUGH OVERNIGHT HAS STABILIZED MUCH OF THE MIDSOUTH AND THE MAIN FOCUS FOR HEAVY RAIN HAS SHIFTED SOUTH OF THE AREA. LATEST HRRR INDICATES THAT SCT REDEVELOPMENT WILL OCCUR THIS AFTERNOON AS AIRMASS TRIES TO DESTABILIZE AGAIN DUE TO SURFACE HEATING BUT COVERAGE WILL BE LIMITED AND THE WIDESPREAD HEAVY RAIN THREAT HAS DIMINISHED. AS A RESULT DECIDED TO CANCEL FLASH FLOOD WATCH EARLY. SJM && PREV DISCUSSION... /ISSUED 422 AM CDT MON MAY 18 2015/ A WEAKENING MESOSCALE CONVECTIVE SYSTEM (MCS) WAS LOCATED ALONG THE TN RIVER OF WEST TN INTO NORTHEAST MS EARLY THIS MORNING. THE MCS WAS PUSHING TO THE NORTHEAST. ANOTHER MCS WAS STRENGTHENING OVER NORTH LA AND LOOKS LIKE IT MIGHT SKIRT SOUTHERN PORTIONS OF NORTH MS WITH THE POSSIBILITY OF VERY HEAVY RAINFALL. WITH THE HEAVIER STORMS EARLIER TONIGHT ACROSS NORTH MS...VERY HEAVY RAINFALL WAS INDICATED IN SOME SPOTS...IN EXCESS OF 2 INCHES PLUS PER HOUR AS SHOWN BY DUAL POL RADAR. WILL KEEP THE FLASH FLOOD WATCH GOING FOR TODAY. LATEST MODELS DID COME IN WITH POPS A LITTLE LOWER FOR TODAY ESPECIALLY ACROSS AREAS TO THE NORTHWEST INCLUDING NORTHEAST AR AND THE MO BOOTHEEL. ALSO...MODELS ARE SHOWING PRECIPITABLE WATER VALUES DECREASING SLIGHTLY FROM THE NORTHWEST DURING THE DAY. NEVERTHELESS...A COLD FRONT WILL APPROACH THE REGION FROM THE NORTH TODAY MOVING INTO NORTHEAST AR LATE THIS AFTERNOON OR EARLY EVENING. INSTABILITY WILL INCREASE ACROSS THE AREA ALLOWING FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT. PRECIPITABLE WATER VALUES WILL BE BETWEEN 1.5 AND 2.1 INCHES ACROSS MOST OF THE AREA. WITH STORMS BEING VERY EFFICIENT RAIN PRODUCERS...THINK LOCALLY HEAVY RAINFALL COULD STILL BE A PROBLEM LEADING TO FLASH FLOODING. ALSO... THINK INSTABILITY WILL BE SUFFICIENT TO SUPPORT A FEW STRONG THUNDERSTORMS WITH STRONG GUSTY WINDS AND SMALL HAIL. THE COLD FRONT IS FORECAST TO MOVE THROUGH THE MIDSOUTH TONIGHT AND TUESDAY...ALTHOUGH THE NAM AND ECWMF ARE SLOWER WITH THE PASSAGE OF THE FRONT THAN THE GFS. THINK THE CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY WILL BE MAINLY ACROSS EAST CENTRAL AR INTO PORTIONS OF NORTH MS. DRIER AND A LITTLE COOLER AIR WILL SPREAD INTO THE REGION NORTH OF THE FRONT. THUS MUCH OF THE REGION WILL HAVE A VERY NICE SPRING DAY TUESDAY. FOR TUESDAY NIGHT INTO THURSDAY...FOLLOWED THE ECMWF / NAM SOLUTION VERSUS THE GFS. THE ECMWF AND NAM INDICATE THAT THE FRONTAL SYSTEM WILL PUSH BACK TO NORTH TUESDAY NIGHT WITH THE MIDSOUTH ONCE AGAIN IN THE WARM SECTOR WEDNESDAY. SURFACE HIGH PRESSURE WILL THEN PUSH THE FRONT BACK THROUGH THE REGION WEDNESDAY NIGHT AS A COLD FRONT. THIS WOULD RESULT IN ANOTHER THREAT OF HEAVY RAINFALL AND POSSIBLY A FEW STRONG TO SEVERE THUNDERSTORMS WEDNESDAY. HOWEVER...CONFIDENCE IS LOW AND DID NOT MENTION IN THE HAZARDOUS WEATHER OUTLOOK WITH THE GFS KEEPING THE FRONTAL SYSTEM MORE TO OUR SOUTH AND MOST OF OUR FORECAST AREA NOT GETTING BACK INTO THE WARM SECTOR. MODELS DO AGREE THAT DURING THE DAY THURSDAY DRIER AND A LITTLE COOLER AIR WILL SPREAD IN FROM THE NORTH ENCOMPASSING THE ENTIRE AREA BY THURSDAY NIGHT. PLEASANT AND DRY SPRING WEATHER WILL OCCUR FRIDAY AND FOR MOST OF THE AREA SATURDAY. ANOTHER LARGE SCALE UPPER LEVEL TROUGH WILL APPROACH FROM THE WEST BY THE LATTER HALF OF THE WEEKEND BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS...BUT ONCE AGAIN AS OBSERVED MUCH OF THIS SPRING...THE TROUGH IS FORECAST TO LIFT TO THE NORTHEAST AS STRONG UPPER LEVEL HIGH PRESSURE IS LOCATED ALONG THE SOUTHEASTERN UNITED STATES COAST. JCL && .AVIATION... 12Z TAFS WIDESPREAD LIGHT RAINFALL WITH A FEW EMBEDDED LIGHTNING STRIKES THIS MORNING ACROSS MOST TERMINALS EXCEPT JBR...WHICH HAS MANAGED TO CLEAR. SIMILAR TO THE PAST FEW DAYS...SHOWERS AND THUNDERSTORMS ARE FORECAST TO REDEVELOP TOWARD 17Z ACROSS ALL TERMINALS. COVERAGE OF STORMS SHOULD BE LESS TODAY AND THERE IS A LITTLE MORE UNCERTAINTY IN THAT ASPECT...BUT VCTS IS IN THE FORECAST AT ALL TERMINALS TO ACCOUNT FOR THIS AS OF NOW. CLOUD COVER SHOULD ALSO BE ABUNDANT TODAY...WITH A PERSISTENT BKN TO OVC DECK. A FRONTAL BOUNDARY SHOULD BRING AN END TO THE PRECIP LATE THIS AFTERNOON WITH CIGS LIFTING AFTER 00Z. THE EXCEPTION TO THIS WILL BE TUP WHERE GUIDANCE IS AGGRESSIVE ON DEVELOPING AN IFR DECK AFTER 06Z. DID NOT BRING CIGS DOWN THAT LOW YET BUT TRENDED DOWNWARD...SO THIS WILL NEED TO BE WATCHED. WINDS SHOULD MAINLY BE SOUTH-SOUTHWESTERLY AROUND 10 MPH THROUGH THE DAY. TVT && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1255 PM CDT MON MAY 18 2015 .AVIATION... VFR DETERIORATING TO IFR TONIGHT AT ALL SITES. SURGE OF MOISTURE INTO THE REGION WILL BREED SCT TSRA SW OF LBB LATER THIS AFTN BEFORE REACHING LBB AND PVW THIS EVENING. MUCH BETTER CHANCE FOR WIDESPREAD TSRA DEVELOPMENT SHOULD OCCUR EARLY TUE MORNING FROM W-E AS AN UPPER TROUGH REACHES THE AREA. IFR CIGS ARE LIKELY TO PERSIST THRU 18Z TUE AS MOIST E-SE UPSLOPE WINDS PERSIST. && PREV DISCUSSION... /ISSUED 340 AM CDT MON MAY 18 2015/ SHORT TERM... THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY AS LATE THIS AFTN. THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS. COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES INDEED OCCUR. ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00- 1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS. WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40 KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY THREATS/. A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND 80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S. LONG TERM... THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL BEGIN TO THIN FROM WEST TO EAST. WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM. THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD AND THEN RETREATS FRIDAY AND SATURDAY. TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE CAA ASSOCIATED WITH THE FROPA. ALDRICH && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 93
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
648 PM EDT MON MAY 18 2015 .SYNOPSIS... A COLD FRONT EXTENDS FROM MICHIGAN TO SOUTHERN MISSOURI. THIS FRONT WILL MOVE EAST ACROSS THE OHIO VALLEY OVERNIGHT...CROSSING THE MID ATLANTIC REGION TUESDAY. MOIST SOUTHERLY FLOW AHEAD OF THE FRONT WILL HELP FUEL SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. ONCE THE FRONT PASSES EAST OF THE AREA TUESDAY...COOLER...DRIER AIR WILL FILTER INTO THE REGION FOR MID WEEK. && .NEAR TERM /THROUGH TUESDAY/... AS OF 640 PM EDT MONDAY... NO MAJOR CHANGES TO THE FORECAST AS WE HEAD INTO THE EVENING HOURS. WE STILL EXPECT SCATTERED SHOWERS AND SOME STORMS ACROSS MUCH OF THE REGION. WHAT DID CHANGE WAS THE FOCUS FOR WHERE THE BEST CHANCES WOULD BE IN THE NEXT COUPLE OF HOURS BASED UPON WHERE THE GREATEST CONCENTRATION IS CURRENTLY LOCATED...FROM FRANKLIN COUNTY VA SOUTHWEST TO AROUND PILOT MOUNTAIN IN NORTH CAROLINA...AND WEST TO THE GRAYSON HIGHLANDS OF SOUTHWEST VIRGINIA. ALSO...ANOTHER GENEROUS REGION OF PRECIPITATION WAS MOVING THROUGH ROCKBRIDGE COUNTY VA...AND THERE WAS ANOTHER ONE APPROACHING WESTERN GREENBRIER COUNTY AND SUMMERS COUNTY IN SOUTHEAST WEST VIRGINIA. AS WE PROGRESS INTO THE LATE EVENING AND TOWARDS MIDNIGHT....FORECAST CHANGES WERE A LITTLE MORE EXPANSIVE. BASED UPON THE LATEST HRRR AND RNK WRF. THE FORECAST WILL NOW REFLECT LITTLE OR NO COVERAGE OF PRECIPITATION OUTSIDE SOUTHEAST WEST VIRGINIA AND NEIGHBORING PORTIONS OF SOUTHWEST VIRGINIA ONCE WE REACH THAT TIME TONIGHT. AS OF 330 PM EDT MONDAY... PWATS 2-3 STANDARD DEVIATIONS ABOVE NORMAL WILL HELP FUEL SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS EVENING. THE AIRMASS IS UNSEASONABLY JUICY BUT LACK OF ANY GOOD DYNAMICS SHOULD KEEP ACTIVITY UNORGANIZED. NEVER THE LESS...SLOW MOVEMENT WILL YIELD HEAVY DOWNPOURS FOR ANY PASSING SHOWER/STORM. FORECAST AREA REMAINS UNDERNEATH A VERY SHARP UPPER LEVEL RIDGE...WHICH IS PROMOTING VERY LIGHT STEERING WINDS...0-8KM MEAN WIND OF ONLY 11 KTS...FROM 290 DEGREES. THIS UPPER RIDGE IS EXPECTED TO WEAKEN AS WE TRANSITION THROUGH THE NEXT 12-18 HOURS...AS LOW PRESSURE MOVES ACROSS THE GREAT LAKES AND INTO ONTARIO CANADA. AT THE SURFACE...A COLD FRONT WILL TRAIL SOUTH FROM THE LOW...CROSSING THE OHIO VALLEY TONIGHT. AS THE FRONT APPROACHES...IT WILL FOCUS THE DEEPER MOISTURE FROM THE OH/TN VALLEYS INTO THE WEST SIDE OF THE APPALACHIANS. THIS SQUEEZE PLAY OF DEEPER MOISTURE IN ADDITION TO LINGERING INSTABILITY OVER THE MOUNTAINS WILL RESULT IN GOOD COVERAGE OF SHOWER ACTIVITY THROUGH THIS EVENING. COVERAGE AND INTENSITY OF SHOWER AND THUNDERSTORM ACTIVITY WILL DECREASE WITH THE LOSS OF DAYTIME HEATING. HOWEVER...WITH THE COLD FRONT CONTINUING ITS APPROACH OVERNIGHT...SHOWER THREAT WILL NOT SUBSIDE ALTOGETHER. MOISTURE TRANSPORT AND CONVERGENCE PER SOUTHWEST WIND FLOW AHEAD OF THE FRONT WILL CONTINUE TO GENERATE ACTIVITY INTO THE LATE NIGHT. SURFACE FRONT IS EXPECTED TO REACH THE WESTERN SLOPES OF THE APPALACHIANS BY DAYBREAK TUESDAY...THEN MOVE OVER AND EAST OF THE MTNS MID-DAY...CLEARING THE CWA BY TUESDAY EVENING. WILL MAINTAIN THREAT FOR SHOWERS UNTIL THE PASSAGE OF THE FRONT...FOLLOWED BY CLEARING AND DRYING WITH FROPA. MET/MAV TEMPERATURE GUIDANCE LOOKS GOOD...AND USED A BLEND FOR TONIGHT`S LOWS AND TUESDAYS HIGHS...READINGS REMAINING QUITE MILD TONIGHT...AOA 60 FOR LOWS...FOLLOWED BY ANOTHER WARM DAY TUESDAY WITH HIGHS RANGING IN THE 70S MTNS TO THE 80S IN THE LOWER ELEVATIONS. ANY SIGNIFICANT COOLING/DRYING WILL NOT TAKE PLACE UNTIL WE CHANGE AIRMASSES LATER TUESDAY...BECOMING NOTICEABLE ONCE THE SUN GOES DOWN TUESDAY EVENING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 300 PM EDT MONDAY... ANY LINGERING CONVECTION IN THE FAR SOUTHEAST PORTIONS OF FORECAST AREA WILL TAPER OFF BY 06Z WEDNESDAY. LOW TEMPERATURES TUESDAY NIGHT WILL RANGE FROM THE UPPER 40S IN THE NORTHWEST MOUNTAINS TO THE LOWER 60S IN THE PIEDMONT. HIGH PRESSURE IN THE MIDWEST WILL RIDGE SOUTHEAST INTO OUR AREA FOR WEDNESDAY PROVIDING A BREAK FROM THE ACTIVE CONVECTION. THE COOLER HIGH TEMPERATURES ON WEDNESDAY WILL ALSO BE A WELCOME CHANGE WITH READINGS FROM THE LOWER 60S IN THE NORTHWEST MOUNTAINS TO THE MID 80S IN THE PIEDMONT. WITH A WEAK SHORTWAVE ROTATING EAST ACROSS THE REGION WEDNESDAY NIGHT...ALLOW FOR SOME LIGHT POPS IN THE WEST. LOW TEMPERATURES WEDNESDAY NIGHT WILL VARY FROM THE UPPER 40S IN THE WEST TO THE UPPER 50S IN THE EAST. THURSDAYS FORECAST REMAINS A CHALLENGE WITH THE LATEST MODEL RUNS ALL DEPICT A STRONGER SHORTWAVE TRACKING ACROSS THE AREA...BUT WITH WIDELY VARYING DEGREES OF INTENSITY AND RESULTANT MOISTURE/PRECIPITATION. WITH CAUTION...ELECTED TO USE A BLEND OF SUPERBLEND AND HPCGUIDE WITH SCATTERED POPS FOR THURSDAY. HIGH TEMPERATURES THURSDAY WILL WARM TO AROUND 60 DEGREES IN THE NORTHWEST TO AROUND 80 DEGREES ALONG THE SOUTHERN BLUE RIDGE. SHORTWAVE WILL EXIT TO THE SOUTHEAST THURSDAY NIGHT AS SFC HIGH PRESSURE SLIDES FROM THE PLAINS TO THE GREAT LAKES. OVERALL...THE AIRMASS APPEARS TO BE TOO STABLE AND DRY IN THE LOWER LEVELS TO SUPPORT MUCH THUNDER WITH THIS EVENT. HOWEVER...A NOSE OF INSTABILITY SUPPORT ISOLATED THUNDERSTORM ACROSS SOUTHERN PORTIONS OF FORECAST AREA. DIURNAL CONVECTION TAPERS OFF QUICKLY THURSDAY NIGHT. LOW TEMPERATURES THURSDAY NIGHT WILL GENERALLY VARY FROM THE UPPER 40S IN THE MOUNTAINS TO THE UPPER 50S IN THE PIEDMONT. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 300 PM EDT MONDAY... MOISTURE...WARMTH...AND HUMIDITY ARE POISED TO RETURN BY EARLY NEXT WEEK AS YET ANOTHER DEEP UPPER LOW BUILDS INTO THE SOUTHWEST UNITED STATE...THE NORTHEAST TROUGH PUSHES EASTWARD INTO THE NORTHERN ATLANTIC...AND AN ELONGATED RIDGE BETWEEN THESE TWO FEATURES DRIFTS INTO OUR REGION. HIGH TEMPERATURES FRIDAY WARM INTO THE MID 60S IN THE MOUNTAINS TO THE MID 70S IN THE PIEDMONT. LOW TEMPERATURES WILL DROP INTO THE MID 40S TO THE 50S IN GENERAL. ON SATURDAY...CANADIAN HIGH PRESSURE SHIFTS OFF THE MID-ATLANTIC COAST...AS FRONTAL BOUNDARY IS CENTRAL U.S. LIFTS NORTHEAST. KEPT SATURDAY DRY...WITH HIGH TEMPERATURES RANGING FROM THE MID 60S IN THE NORTHWEST MOUNTAINS TO THE UPPER 70S IN THE PIEDMONT. AS THE HIGH CENTER MOVES EAST...AN EAST TO SOUTHEAST RETURN FLOW ON THE BACKSIDE MAY DEVELOP A WEDGE ACROSS THE REGION OVER THE WEEKEND. WITH THE POTENTIAL OF OVERRUNNING PRECIPITATION DEVELOPING FROM THE WEST. ADDED A SLIGHT CHANCE OF SHOWERS IN THE NORTHWEST MOUNTAINS OF NORTH CAROLINA. MODERATED LOW TEMPERATURES SATURDAY NIGHT WITH VALUES MAINLY IN THE 50S...WITH INCREASED CLOUD COVER. SCATTERED SHOWERS CONTINUED ON SUNDAY WITH THE BEST CHANCES IN THE NORTHWEST. THE UPPER RIDGE WILL SHIFT SOUTHEAST BY MONDAY...ALLOWING AN ACTIVE BAROCLINIC ZONE TO SHIFT SOUTH AND EAST INTO THE REGION FROM THE OH/TN VALLEY. CONTINUED THE POTENTIAL FOR SCATTERED CONVECTION ON TUESDAY. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 200 PM EDT MONDAY... A VERY MOIST AIR MASS REMAINS ACROSS THE REGION STUCK UNDER AN UPPER RIDGE AS THE PAST SEVERAL DAYS. HOWEVER...THE PATTERN IS FINALLY ABOUT TO CHANGE. THE UPPER LOW THAT HAS PLAGUED THE CENTRAL U.S. THE PAST SEVERAL DAYS IS SHEARING OUT AND MOVING TOWARD THE GREAT LAKES WHERE IT WILL AID IN THE DEVELOPMENT OF A DEEP UPPER LOW ACROSS SOUTHEAST CANADA BY MIDWEEK. THIS WILL PUSH A FRONT INTO OUR REGION BY EARLY TUESDAY...THEN EAST OF THE REGION BY TUE EVENING. FOR THIS AFTERNOON AND EVENING...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED IN ADVANCE OF THE UPPER TROUGH/FRONT. THE ACTIVITY WILL EXTEND FROM THE OH/TN VALLEYS EASTWARD INTO THE MID ATLANTIC...AND FARTHER EAST INTO THE PIEDMONT AS COMPARED TO THE PAST FEW AFTERNOONS. DURING THE AFTERNOON/EVENING...THUNDERSTORMS SHOULD BE MOST NUMEROUS WEST OF THE BLUE RIDGE...SOME WITH LOCALLY HEAVY RAINFALL. THE STRONGER STORMS WILL CONTAIN LOCALIZED OUTFLOW WINDS OF 25-30KTS IN ADDITION TO MVFR CIGS AND BRIEF PERIODS OF MVFR-IFR VSBYS. LACK OF ORGANIZATION MAKES IT DIFFICULT TO PINPOINT TIMING AT ANY OF THE TERMINALS...ESP THOSE EAST OF THE BLUE RIDGE. AS SUCH...WILL CONTINUE TO MENTION VCNTY SHRA/TSRA AND AMEND TAFS PER RADAR TRENDS. COVERAGE OF THE SHOWERS/THUNDERSTORMS WILL DECREASE AFTER SUNSET...BUT GIVEN THE SYNOPTIC PATTERN WOULD EXPECT SOME ACTIVITY TO LINGER ALL NIGHT ACROSS MUCH OF THE CWA. WITH WINDS BECOMING NW...UPSLOPE MVFR CIGS APPEAR LIKELY ACROSS EASTERN WV INTO FAR SOUTHWEST VA...WITH MODELS SUGGESTING PERIOD OF IFR CIGS PRIOR TO DAYBREAK TUESDAY AT KBLF/KLWB. MVFR VSBYS WILL ALSO PREVAIL IN MANY AREAS OVERNIGHT IN A NEAR SATURATED BOUNDARY LAYER WITH MOIST/WET GROUND AND LIGHT WSW-WNW WINDS. ANY LOW CIG/VSBY ELEMENTS SHOULD QUICKLY IMPROVE AFTER 13Z/9AM TUESDAY WITH RETURN OF VFR FOR THE AFTERNOON. SURFACE FRONT WILL PASS THROUGH ALL TERMINALS TUESDAY WITH SKIES CLEARING AND WINDS BECOMING NORTHWEST 6 TO 12 KTS. EXTENDED AVIATION DISCUSSION... DRIER/COOLER CONDITIONS ARE EXPECTED TUESDAY NIGHT AND WEDNESDAY. AN UPPER DISTURBANCE WILL LIKELY BRING SOME MVFR CIGS AND -SHRA BACK INTO THE AREA THU...MOVING OUT FRIDAY WITH VFR CONDITIONS RETURNING FRI-SAT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...DS/PM SHORT TERM...KK LONG TERM...KK AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
550 PM CDT MON MAY 18 2015 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 235 PM CDT MON MAY 18 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED LOW PRESSURE MOVING EAST OVER WESTERN LAKE SUPERIOR. A VERY CHILLY AIRMASS FOR THIS TIME OF THE YEAR IS WRAPPING AROUND THE LOW AND GRADUALLY MOVING EAST OVER THE WESTERN HALF OF WISCONSIN. THE LOW STRATUS HAS MOVED VERY LITTLE EASTWARD SO FAR TODAY...BUT SHOULD GAIN SOME MOMENTUM THROUGH THE AFTERNOON AS THE COLDER AIR AT 850MB OVER TAKES IT. PLENTY OF OBS ARE REPORTING LIGHT RAIN/DRIZZLE...AND EVEN A FEW FLAKES UPSTREAM OVER NORTHWEST WISCONSIN AND NORTHERN MINNESOTA. AS THE COLDER AIR AND LIGHT PRECIP SPREAD ACROSS THE REGION...TEMPS AND PRECIP TRENDS ARE THE MAIN FORECAST CONCERNS. TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE EAST OVER LAKE SUPERIOR AND NORTHERN ONTARIO AND WEAKEN AT THE SAME TIME. AS WINDS SHIFT TO THE NORTHWEST...COLD ADVECTION WILL CONTINUE ACROSS THE STATE THROUGH THE NIGHT...DROPPING 850MB TEMPS TO AROUND -8C TO -10C. DEEPER MOISTURE WILL BE ROTATING ACROSS NORTHERN WISCONSIN AND COMBINED WITH UPSLOPE FLOW OFF LAKE SUPERIOR AND UNSTABLE CONDITIONS...SHOULD SEE PERIODS OF LIGHT RAIN/DRIZZLE...MIXED WITH SNOW AT TIMES. TEMPERATURES WILL BE FALLING INTO THE 30-32 DEGREE RANGE OVER NORTHERN WISCONSIN FOR A FEW HOURS LATE TONIGHT. BUT AREAS OVER THE UPPER PENINSULA AND NORTHWEST WISCONSIN HAVE NOT OFFICIALLY STARTED THEIR GROWING SEASONS...SO WILL HIGHLIGHT THE COLD IN A SPECIAL WEATHER STATEMENT. ELSEWHERE...LOOK FOR A CLOUDY AND BLUSTERY NIGHT. TUESDAY...THERMAL TROUGHING AND FLOW OFF LAKE SUPERIOR ARGUE FOR A CLOUDY/MOSTLY CLOUDY START TO THE DAY. BUT SHOULD SEE CLOUDS GRADUALLY ERODE FROM SOUTHWEST THROUGH NORTHEAST THROUGH THE DAY AS CYCLONIC FLOW ABATES AND LOW LEVEL TEMPS MODERATE. LOWERED MAX TEMPS A DEGREE...AND WENT WITH HIGHS RANGING FROM THE MID 40S NORTH TO MID 50S SOUTH. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 235 PM CDT MON MAY 18 2015 FROST/FREEZE HEADLINE POTENTIAL TUESDAY NIGHT AND WEDNESDAY NIGHT... AND PCPN TRENDS FOR THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST CONCERNS. CANADIAN HIGH PRESSURE WILL BE RIDGED OVER THE WSTRN GREAT LAKES ON TUESDAY NIGHT...AND WILL BRING LIGHT WINDS TO THE FORECAST AREA. EXPECT SKIES TO BE MOSTLY CLEAR OVER NORTHERN WI...LEADING TO WIDESPREAD SUB-FREEZING TEMPERATURES. AVERAGE MIXING RATIOS OF 2.5 TO 3 G/KG SUPPORT THE POTENTIAL FOR MIN TEMPS AS COLD AS 20 TO 25 AT THE CLIMATOLOGICALLY FAVORED COLD SPOTS. HIGH CLOUDS ARE EXPECTED TO INCREASE OVER C/EC WI...ON THE ANTICYCLONIC SHEAR SIDE...AND WITHIN THE RRQ...OF A STRONG UPPER JET STREAK. WHILE THIS LIKELY WILL NOT PREVENT FROST DEVELOPMENT IN OUR SOUTHERN COUNTIES...IT SHOULD AT LEAST KEEP MOST PLACES ABOVE FREEZING. WILL NOT ISSUE ANY HEADLINES WITH THIS FORECAST PACKAGE...BUT FROST/FREEZE HEADLINES APPEAR IMMINENT. THE POTENTIAL FOR FROST WILL CONTINUE INTO WEDNESDAY NIGHT... BUT SHOULD SHIFT TO MAINLY NORTHERN WI...WHERE MIN TEMPS ARE EXPECTED TO DROP INTO THE LOWER TO MIDDLE 30S. A WEAK BACK DOOR COLD FRONT IS EXPECTED TO DROP SOUTH THROUGH THE REGION SOMETIME DURING THE WEDS NGT TO THU NGT PERIOD. THE GFS IS FOCUSING ON WEDS NGT/THU...WHILE THE ECMWF IS SLOWER AND BRINGS THE FRONT THROUGH THU AND EARLY THU NGT. A VERY DRY AIR MASS SHOULD PRECLUDE ANY PCPN DEVELOPMENT. CANADIAN HIGH PRESSURE WILL RETURN TO THE WSTRN GREAT LAKES FRIDAY...AND SHOULD HOLD ANY PCPN AT BAY THROUGH AT LEAST SATURDAY. A COLD FRONT/INVERTED SFC TROF AND UPPER TROF WILL IMPACT THE REGION FOR THE LATTER HALF OF THE MEMORIAL DAY WEEKEND...BUT TIMING DIFFERENCES ARE SIGNIFICANT BETWEEN THE MODELS. THE GFS HAS PCPN OVER THE REGION FROM SAT NGT THROUGH MONDAY...WITH THE HEAVIEST QPF FCST ON SUNDAY. THE ECMWF IS SLOWER...AND FOCUSES MOST OF THE PCPN DURING THE SUNDAY NIGHT AND MONDAY PERIODS. DUE TO THE TIMING DIFFERENCES...HAVE BACKED OFF ON LIKELY POPS FOR ANY SPECIFIC PERIOD...BUT OVERALL TRENDS SUPPORT AT LEAST A PERIOD OR TWO OF MODERATE RAINFALL. SLIGHTLY BLO NORMAL TEMPERATURES ARE EXPECTED AT THE BEGINNING AND END OF THE EXTENDED PERIOD...WITH NEAR NORMAL READINGS FOR THE REST OF THE DAYS. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 548 PM CDT MON MAY 18 2015 A MUCH COLDER AIR MASS WILL POUR ACROSS THE TAF SITES OVER THE NEXT 24 HOURS. OCCASIONAL RAIN SHOWERS...DRIZZLE AND A SNOW SHOWER OR TWO ARE LIKELY ACROSS NORTH-CENTRAL WISCONSIN TONIGHT AS DEEPER MOISTURE MOVES OVERHEAD. OTHERWISE...WINDS WILL VEER TO THE NORTHWEST TONIGHT AND REMAIN GUSTY. BROKEN MVFR CIGS WILL SPREAD EAST INTO EASTERN WISCONSIN LATER THIS EVENING AND HANG AROUND INTO TUESDAY MORNING. COOL DRY HIGH PRESSURE SETTLING INTO THE GREAT LAKES REGION WILL PRODUCE VFR CIGS LATER TUESDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......KIECKBUSCH AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 235 PM CDT MON MAY 18 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED LOW PRESSURE MOVING EAST OVER WESTERN LAKE SUPERIOR. A VERY CHILLY AIRMASS FOR THIS TIME OF THE YEAR IS WRAPPING AROUND THE LOW AND GRADUALLY MOVING EAST OVER THE WESTERN HALF OF WISCONSIN. THE LOW STRATUS HAS MOVED VERY LITTLE EASTWARD SO FAR TODAY...BUT SHOULD GAIN SOME MOMENTUM THROUGH THE AFTERNOON AS THE COLDER AIR AT 850MB OVER TAKES IT. PLENTY OF OBS ARE REPORTING LIGHT RAIN/DRIZZLE...AND EVEN A FEW FLAKES UPSTREAM OVER NORTHWEST WISCONSIN AND NORTHERN MINNESOTA. AS THE COLDER AIR AND LIGHT PRECIP SPREAD ACROSS THE REGION...TEMPS AND PRECIP TRENDS ARE THE MAIN FORECAST CONCERNS. TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE EAST OVER LAKE SUPERIOR AND NORTHERN ONTARIO AND WEAKEN AT THE SAME TIME. AS WINDS SHIFT TO THE NORTHWEST...COLD ADVECTION WILL CONTINUE ACROSS THE STATE THROUGH THE NIGHT...DROPPING 850MB TEMPS TO AROUND -8C TO -10C. DEEPER MOISTURE WILL BE ROTATING ACROSS NORTHERN WISCONSIN AND COMBINED WITH UPSLOPE FLOW OFF LAKE SUPERIOR AND UNSTABLE CONDITIONS...SHOULD SEE PERIODS OF LIGHT RAIN/DRIZZLE...MIXED WITH SNOW AT TIMES. TEMPERATURES WILL BE FALLING INTO THE 30-32 DEGREE RANGE OVER NORTHERN WISCONSIN FOR A FEW HOURS LATE TONIGHT. BUT AREAS OVER THE UPPER PENINSULA AND NORTHWEST WISCONSIN HAVE NOT OFFICIALLY STARTED THEIR GROWING SEASONS...SO WILL HIGHLIGHT THE COLD IN A SPECIAL WEATHER STATEMENT. ELSEWHERE...LOOK FOR A CLOUDY AND BLUSTERY NIGHT. TUESDAY...THERMAL TROUGHING AND FLOW OFF LAKE SUPERIOR ARGUE FOR A CLOUDY/MOSTLY CLOUDY START TO THE DAY. BUT SHOULD SEE CLOUDS GRADUALLY ERODE FROM SOUTHWEST THROUGH NORTHEAST THROUGH THE DAY AS CYCLONIC FLOW ABATES AND LOW LEVEL TEMPS MODERATE. LOWERED MAX TEMPS A DEGREE...AND WENT WITH HIGHS RANGING FROM THE MID 40S NORTH TO MID 50S SOUTH. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 235 PM CDT MON MAY 18 2015 FROST/FREEZE HEADLINE POTENTIAL TUESDAY NIGHT AND WEDNESDAY NIGHT... AND PCPN TRENDS FOR THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST CONCERNS. CANADIAN HIGH PRESSURE WILL BE RIDGED OVER THE WSTRN GREAT LAKES ON TUESDAY NIGHT...AND WILL BRING LIGHT WINDS TO THE FORECAST AREA. EXPECT SKIES TO BE MOSTLY CLEAR OVER NORTHERN WI...LEADING TO WIDESPREAD SUB-FREEZING TEMPERATURES. AVERAGE MIXING RATIOS OF 2.5 TO 3 G/KG SUPPORT THE POTENTIAL FOR MIN TEMPS AS COLD AS 20 TO 25 AT THE CLIMATOLOGICALLY FAVORED COLD SPOTS. HIGH CLOUDS ARE EXPECTED TO INCREASE OVER C/EC WI...ON THE ANTICYCLONIC SHEAR SIDE...AND WITHIN THE RRQ...OF A STRONG UPPER JET STREAK. WHILE THIS LIKELY WILL NOT PREVENT FROST DEVELOPMENT IN OUR SOUTHERN COUNTIES...IT SHOULD AT LEAST KEEP MOST PLACES ABOVE FREEZING. WILL NOT ISSUE ANY HEADLINES WITH THIS FORECAST PACKAGE...BUT FROST/FREEZE HEADLINES APPEAR IMMINENT. THE POTENTIAL FOR FROST WILL CONTINUE INTO WEDNESDAY NIGHT... BUT SHOULD SHIFT TO MAINLY NORTHERN WI...WHERE MIN TEMPS ARE EXPECTED TO DROP INTO THE LOWER TO MIDDLE 30S. A WEAK BACK DOOR COLD FRONT IS EXPECTED TO DROP SOUTH THROUGH THE REGION SOMETIME DURING THE WEDS NGT TO THU NGT PERIOD. THE GFS IS FOCUSING ON WEDS NGT/THU...WHILE THE ECMWF IS SLOWER AND BRINGS THE FRONT THROUGH THU AND EARLY THU NGT. A VERY DRY AIR MASS SHOULD PRECLUDE ANY PCPN DEVELOPMENT. CANADIAN HIGH PRESSURE WILL RETURN TO THE WSTRN GREAT LAKES FRIDAY...AND SHOULD HOLD ANY PCPN AT BAY THROUGH AT LEAST SATURDAY. A COLD FRONT/INVERTED SFC TROF AND UPPER TROF WILL IMPACT THE REGION FOR THE LATTER HALF OF THE MEMORIAL DAY WEEKEND...BUT TIMING DIFFERENCES ARE SIGNIFICANT BETWEEN THE MODELS. THE GFS HAS PCPN OVER THE REGION FROM SAT NGT THROUGH MONDAY...WITH THE HEAVIEST QPF FCST ON SUNDAY. THE ECMWF IS SLOWER...AND FOCUSES MOST OF THE PCPN DURING THE SUNDAY NIGHT AND MONDAY PERIODS. DUE TO THE TIMING DIFFERENCES...HAVE BACKED OFF ON LIKELY POPS FOR ANY SPECIFIC PERIOD...BUT OVERALL TRENDS SUPPORT AT LEAST A PERIOD OR TWO OF MODERATE RAINFALL. SLIGHTLY BLO NORMAL TEMPERATURES ARE EXPECTED AT THE BEGINNING AND END OF THE EXTENDED PERIOD...WITH NEAR NORMAL READINGS FOR THE REST OF THE DAYS. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1207 PM CDT MON MAY 18 2015 A MUCH COLDER AIRMASS WILL FILTER ACROSS THE TAF SITES OVER THE NEXT 24 HOURS. OCCASIONAL RAIN SHOWERS...DRIZZLE...AND A SNOW SHOWER OR TWO ARE LIKELY ACROSS NORTH-CENTRAL WISCONSIN TONIGHT AS DEEPER MOISTURE MOVES OVERHEAD. OTHERWISE...WINDS WILL VEER TO THE NORTHWEST TONIGHT AND REMAIN GUSTY. BROKEN MVFR CIGS WILL SPREAD EAST INTO EASTERN WISCONSIN THIS EVENING AND LOOK TO HANG AROUND THROUGH THE END OF THE TAF PERIOD. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......KIECKBUSCH AVIATION.......MPC