Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/14/15


AREA FORECAST DISCUSSION
NWS TUCSON AZ
330 PM MST TUE MAY 12 2015 .SYNOPSIS...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY EAST OF TUCSON TONIGHT. DRY CONDITIONS WILL THEN PREVAIL WEDNESDAY INTO THURSDAY. A STRONG LOW PRESSURE SYSTEM WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY. COOLER TEMPERATURES AND GUSTY WINDS WILL ACCOMPANY THIS SYSTEM. EXPECT DRY CONDITIONS AND MUCH WARMER TEMPERATURES EARLY NEXT WEEK. && .DISCUSSION...IR/VISIBLE SATELLITE IMAGERY DEPICTED FAIRLY THICK MID AND HIGH-LEVEL CLOUDS ACROSS MUCH OF SE ARIZONA THIS AFTERNOON. MORE EXTENSIVE BREAKS IN THE OVERCAST WERE NOTED ACROSS WRN PIMA COUNTY. THE BACK EDGE OF THIS CLOUD MASS REPRESENTING A SHORTWAVE TROUGH AXIS EXTENDED FROM SRN CALIFORNIA SOUTHWARD TO NEAR THE BAJA CALIFORNIA SPUR. MEANWHILE...A VERY DRY SURFACE ENVIRONMENT WAS ONGOING WITH DEWPOINTS AT LOWER ELEVATIONS VALID 22Z RANGING FROM THE MID TEENS TO MID 20S. HAVE FAVORED SEVERAL RUC HRRR SOLUTIONS FOR PRECIP POTENTIAL THRU TONIGHT. THUS...THERE IS A SLIGHT CHANCE OF SHOWERS/TSTMS THIS EVENING FROM TUCSON EWD/SWD TO THE NEW MEXICO/INTERNATIONAL BORDERS. A SLIGHT CHANCE OF SHOWERS CONTINUES MAINLY NEAR THE NEW MEXICO BORDER LATE TONIGHT. GIVEN THE VERY DRY NEAR-SURFACE ENVIRONMENT...ANY MEASURABLE PRECIP AMOUNTS WILL BE QUITE LIGHT. CLEARING SKIES WILL OCCUR FROM WEST-TO-EAST LATE TONIGHT AS THE MID-LEVEL TROUGH AXIS MOVES INTO SWRN NEW MEXICO. FLOW ALOFT WILL BECOME INCREASINGLY SWLY WED-THUR IN RESPONSE TO DEEPENING LOW PRESSURE ALOFT OVER THE ERN PACIFIC. THE TIGHTENING MID-LEVEL GRADIENT WILL PRODUCE BREEZY TO WINDY CONDITIONS... ESPECIALLY DURING THE AFTERNOON HOURS. EXPECT THE STRONGEST WIND SPEEDS TO OCCUR THUR. 12/12Z GFS/ECMWF/CMC WERE IN GOOD AGREEMENT WITH DEPICTING A 550 DM LOW TO BE CENTERED NEAR THE CENTRAL CALIFORNIA COAST FRI MORNING. THIS UPPER LOW IS THEN PROGGED TO BE CENTERED OVER WYOMING SAT MORNING...WITH A MID-LEVEL TROUGH AXIS TO EXTEND SWWD INTO SRN ARIZONA. BASED ON THESE SOLUTIONS...APPEARS THE BEST CHANCE OF MEASURABLE PRECIP FOR THE TUCSON METRO AREA WOULD OCCUR FRI NIGHT. THE GRIDDED DATA POP FIELDS WERE ADJUSTED TO REFLECT THIS SCENARIO. AT ANY RATE...THERE IS A SLIGHT CHANCE OF SHOWERS MAINLY NORTH OF TUCSON FRI MORNING. PRECIP CHANCES INCREASE FRI AFTERNOON...AND A CHANCE OF SHOWERS/TSTMS EXISTS ACROSS MUCH OF THE AREA FRI NIGHT. A CHANCE OF SHOWERS CONTINUES SAT MAINLY ACROSS THE WHITE MOUNTAINS. DRY CONDITIONS SHOULD OCCUR BY SAT AFTERNOON FROM TUCSON WWD ACROSS THE WRN DESERTS. DRY CONDITIONS WILL PREVAIL AREA-WIDE LATE SAT NIGHT AND CONTINUE THRU TUE UNDER GENERALLY SWLY FLOW ALOFT. WARMER TEMPS WILL OCCUR WED FOLLOWED BY A FEW DEGS OF COOLING THUR...THEN MORE SIGNIFICANT COOLING IS ON TAP FRI. MARKEDLY WARMER TEMPS WILL PREVAIL SUN-TUE. && .AVIATION...VALID THRU 14/00Z. EXPECT ISOLATED -SHRA/-TSRA FROM KTUS VICINITY EASTWARD TO THE NEW MEXICO BORDER THIS EVENING. ISOLATED -SHRA WILL THEN PREVAIL MAINLY NEAR THE NEW MEXICO BORDER LATE TONIGHT...THEN DRY CONDITIONS WILL OCCUR AREA-WIDE WEDNESDAY. OTHERWISE...CLOUD DECKS THRU ABOUT 06Z- 09Z WEDNESDAY WILL GENERALLY BE AT 6-12K FT AGL FOLLOWED BY DECREASING CLOUDS EARLY WEDNESDAY MORNING. CLEAR SKIES TO SCATTERED CLOUDS ABOVE 10K FT AGL WILL PREVAIL WEDNESDAY AFTERNOON. SURFACE WIND EARLY THIS EVENING AND WEDNESDAY AFTERNOON WILL BE SLY/SWLY AT 12-20 KTS WITH GUSTS OF 20-30 KTS. SURFACE WIND WILL GENERALLY BE LESS THAN 10 KTS AT OTHER TIMES. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY EAST OF TUCSON TONIGHT. DRY CONDITIONS WILL THEN PREVAIL WEDNESDAY INTO THURSDAY. THE COMBINATION OF STRONG AND GUSTY WINDS AND LOW RELATIVE HUMIDITIES MAY CREATE CRITICAL FIRE WEATHER CONDITIONS AT LOWER ELEVATIONS THURSDAY AFTERNOON AND EARLY THURSDAY EVENING. HOWEVER...WIND SPEEDS AND RELATIVE HUMIDITIES NEEDED TO ACHIEVE RED FLAG CRITERIA WILL BE MARGINAL AND SHORT- LIVED. A STRONG STORM SYSTEM MOVING NORTH OF THE AREA WILL THEN BRING A CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY. COOLER TEMPERATURES AND GUSTY WINDS WILL OCCUR WITH THIS SYSTEM. EXPECT DRY CONDITIONS WITH MUCH WARMER TEMPERATURES EARLY NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST TUE MAY 12 2015 .SYNOPSIS...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS EAST OF TUCSON THROUGH WEDNESDAY MORNING. OTHERWISE...DRY CONDITIONS WILL PREVAIL INTO THURSDAY. A STRONG LOW PRESSURE SYSTEM FROM THE EASTERN PACIFIC WILL THEN BRING A CHANCE OF SHOWERS AND THUNDERSTORMS THURSDAY NIGHT INTO SATURDAY. COOLER TEMPERATURES AND GUSTY WINDS WILL ALSO OCCUR. && .DISCUSSION...IR/VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE PARTLY CLOUDY SKIES ACROSS THE WHITE MOUNTAINS...AND MOSTLY CLOUDY TO CLOUDY SKIES ELSEWHERE. THE THICKER CLOUDINESS AS PER ENHANCED COLDER CLOUD TOPS EXTENDED FROM TUCSON SOUTHWARD TO THE INTERNATIONAL BORDER. DEWPOINTS AT LOWER ELEVATIONS VALID 16Z RANGED FROM THE MID 20S-MID 40S. THESE TEMPS WERE NEARLY 2-5 DEGS F HIGHER VERSUS 24 HOURS AGO EXCEPT IN THE VICINITY OF SAFFORD...WHERE THE DEWPOINT WAS 15 DEGS HIGHER VERSUS THIS TIME MON. SURFACE TEMPS VALID 16Z WERE GENERALLY 2-9 DEGS F COOLER VERSUS 24 HOURS AGO. 12/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 0.40 INCH. THE PROFILE EXHIBITED A VERY DRY SURFACE-500 MB LAYER AND SOME SATURATION OF THE COLUMN ABOVE 500 MB. 12/12Z UPPER AIR PLOTS DEPICTED RIDGE AXIS FROM TEXAS NWWD INTO MONTANA...AND A 548 DM LOW WAS CENTERED OVER SWRN OREGON. MODERATE TO STRONG GENERALLY SWLY FLOW PREVAILED OVER SE ARIZONA. BASED ON SATELLITE IMAGERY AND THE 12/12Z NAM...GRIDDED DATA SKY VALUES WERE INCREASED TO REPRESENT INCREASED CLOUDINESS VERSUS THE PREVIOUS FORECAST. THE 12/12Z NAM LIMITED MEASURABLE PRECIP TO THE WHITE MOUNTAINS TONIGHT. HOWEVER...THE 12/14Z RUC HRRR WAS FURTHER WEST WITH THE POTENTIAL FOR MEASURABLE PRECIP VERSUS THE NAM...AND YIELDED SCATTERED COVERAGE ACROSS GREENLEE/GRAHAM/COCHISE COUNTIES THIS EVENING. THE INHERITED OFFICIAL FORECAST APPEARS TO BE A GOOD COMPROMISE BETWEEN THESE SOLUTIONS. THUS...THERE IS A SLIGHT CHANCE OF SHOWERS/TSTMS THIS AFTERNOON ACROSS THE WHITE MOUNTAINS WITH DRY CONDITIONS ELSEWHERE. A SLIGHT CHANCE OF SHOWERS/TSTMS EXISTS TONIGHT ACROSS ERN SECTIONS WITH DRY CONDITIONS CONTINUING ELSEWHERE. A FEW LINGERING SHOWERS MAY OCCUR WED MORNING NEAR THE NEW MEXICO BORDER...THEN DRY CONDITIONS WILL PREVAIL AREA WIDE INTO THUR AFTERNOON. HIGH TEMPS THIS AFTERNOON WILL GENERALLY BE A FEW DEGS COOLER VERSUS MON. && .AVIATION...VALID THRU 13/18Z. EXPECT ISOLATED -SHRA/-TSRA EAST OF KTUS TO THE NEW MEXICO BORDER INTO WEDNESDAY MORNING. OTHERWISE...INCREASING MAINLY MID AND HIGH- LEVEL MOISTURE THIS MORNING WILL PRODUCE BROKEN TO OVERCAST CLOUD DECKS MAINLY AT 10-15K FT AGL THIS AFTERNOON INTO WEDNESDAY MORNING. SURFACE WIND THIS AFTERNOON AND EARLY THIS EVENING WILL BE SLY/SWLY AT 12-20 KTS WITH GUSTS OF 20-30 KTS. SURFACE WIND WILL THEN DIMINISH TO GENERALLY LESS THAN 10 KTS 02Z-04Z WEDNESDAY AND CONTINUE INTO WEDNESDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS EAST OF TUCSON INTO EARLY WEDNESDAY. OTHERWISE...DRY CONDITIONS WILL PREVAIL THROUGH THURSDAY. EXPECT OCCASIONALLY GUSTY WINDS DURING THE AFTERNOON HOURS INTO WEDNESDAY. A STRONG PACIFIC LOW PRESSURE SYSTEM WILL APPROACH CALIFORNIA THURSDAY. THIS SYSTEM WILL PRODUCE STRONG SOUTHWEST WINDS WITH THE POTENTIAL FOR BORDERLINE RED FLAG CONDITIONS IN ONLY A FEW PLACES. AS THE STORM MOVES CLOSER ON FRIDAY...WINDS WILL INCREASE FURTHER. HOWEVER... HUMIDITY LEVELS WILL BE HIGHER WITH LOWER TEMPERATURES AND A CHANCE FOR SHOWERS AND/OR THUNDERSTORMS. THE SOUTHERN PORTION OF THIS SYSTEM WILL MOVE ACROSS ARIZONA SATURDAY MAINTAINING A THREAT OF SHOWERS AND THUNDERSTORMS. DAYTIME TEMPERATURES WILL BE 10-15 DEGREES COOLER THAN NORMAL SATURDAY...THEN DRIER AND SOMEWHAT WARMER CONDITIONS WILL OCCUR SUNDAY AND MONDAY. && .PREV DISCUSSION...EXPECT A BRIEF RESPITE FROM THE SHOWERS FROM LATE WEDNESDAY THROUGH LATE THURSDAY BEFORE A MUCH STRONGER PACIFIC SYSTEM WILL BEGIN TO AFFECT THE REGION LATE THURSDAY EVENING AND ESPECIALLY OVERNIGHT INTO THE EARLY MORNING HOURS ON FRIDAY AS AN UPPER LOW WILL BE CENTERED OVER THE GREAT BASIN AT THAT TIME. ISOLATED TO SCATTERED SHOWERS WILL AFFECT MOSTLY THE HIGHER TERRAIN THURSDAY NIGHT INTO EARLY FRIDAY. BY FRIDAY AFTERNOON EXPECT ISOLATED SHOWERS AND THUNDERSTORMS AREA-WIDE WITH SCATTERED ACTIVITY OVER PARTS OF GRAHAM AND GREENLEE COUNTIES. THIS WILL CONTINUE INTO FRIDAY NIGHT AND EARLY SATURDAY. MODELS STILL AT ODDS WITH EACH OTHER ON BOTH TIMING AND POP VALUES. LATEST MOS GUIDANCE HAS FLIP- FLOPPED FROM THIS TIME YESTERDAY...WITH THE GFS POPS VALUES RANGING FROM SINGLE DIGITS TO SLIGHT CHANCES ON FRIDAY...THEN IN THE SOLID CHANCE CATEGORY FOR SATURDAY. MEANWHILE...THE ECMWF MOS NUMBERS FOR POP REFLECT SLIGHT CHANCE TO LOW END CHANCE FOR FRIDAY AND SIMILAR FOR SATURDAY. GIVEN THIS CONTINUED UNCERTAINTY...OPTED TO ONLY MAKE MINOR ADJUSTMENTS TO THE FORECAST AND TO BLEND WITH SURROUNDING OFFICES. BY SATURDAY THE UPPER LOW WILL HAVE LIFTED TO THE NORTHEAST INTO THE NORTHERN ROCKIES...MORE SPECIFICALLY OVER SOUTHEASTERN IDAHO AND CENTRAL WYOMING. THE TAIL END OF THIS SYSTEM WILL EXTEND ACROSS NEW MEXICO AND INTO SOUTHEAST ARIZONA AND NORTHERN SONORA. BY THAT TIME THE BULK OF THE MOISTURE WITH THIS SYSTEM WILL BE TO OUR NORTH...SO ONLY EXPECTING A SLIGHT CHANCE OF MOUNTAIN SHOWERS AND/OR THUNDERSTORMS WITH A SLIGHTLY BETTER THREAT FOR PARTS OF GRAHAM AND GREENLEE COUNTIES. BY EARLY SUNDAY THE LOW WILL BE OVER THE NORTHERN ROCKIES/PLAINS STATES WITH WEAK RIDGING BUILDING IN BEHIND THE SYSTEM AND A RETURN TO DRY WEATHER THROUGH THE REMAINDER OF THE FORECAST PERIOD...ALONG WITH WARMING TEMPERATURES INTO EARLY NEXT WEEK. FOR TUCSON...HIGH TEMPERATURES WILL GENERALLY RANGE FROM 2 TO 4 DEGS BELOW NORMAL TODAY THROUGH THURSDAY...THEN 12 TO 16 DEGS BELOW NORMAL FOR FRIDAY AND SATURDAY. THEREAFTER...AROUND 8 TO 10 DEGS BELOW NORMAL FOR SUNDAY AND 3 TO 5 DEGS BELOW NORMAL FOR MONDAY. LOW TEMPS WILL BE NEAR NORMAL WEDNESDAY THROUGH FRIDAY MORNINGS...THEN 6 TO 8 DEGS BELOW NORMAL FOR THE WEEKEND AND 2 TO 4 DEGS BELOW NORMAL FOR EARLY NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON DISCUSSION...FRANCIS PREVIOUS DISCUSSION...MOLLERE AVIATION/FIRE WEATHER...HUMPHREYS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
256 PM MDT TUE MAY 12 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 256 PM MDT TUE MAY 12 2015 AIRMASS IS BECOMING UNSTABLE ALONG THE FRONT RANGE AND NEAR BY EASTERN PLAINS WHERE CAPES ARE UP TO 1000 J/KG. SHOWERS AND STORMS HAVE BEEN SLOW TO FORM OVER THE HIGHER TERRAIN WHERE DEW POINTS ARE IN THE 20S. THE HRRR AND RAP CONTINUE TO SHOW ISOLATED TO SCATTERED CONVECTION LATER THIS AFTERNOON. AS THESE STORMS MOVE OFF THE HIGHER TERRAIN...THEY WILL ENCOUNTER GREATER MOISTURE AND INSTABILITY. EXPECT THE STORMS TO BE CAPABLE OF PRODUCE BRIEF HEAVY...GUSTY OUTFLOW WINDS TO 40 MPH AND SMALL HAIL. WILL KEEP THE ISOLATED TO SCATTERED POPS IN THE FORECAST FOR THE EVENING HOURS. A SHORT WAVE TROUGH CURRENTLY OVER BAJA CALIFORNIA WILL LIFT NORTHEAST ACROSS THE REGION ON WEDNESDAY. EXPECT MOSTLY CLOUDY SKIES AHEAD OF THIS FOR WEDNESDAY. BEST LIFT AND MOISTURE WILL REMAIN TO THE SOUTH AND EAST OF THE AREA. HOWEVER SHOULD BE ENOUGH MOISTURE AND LIFT WITH FOR SCATTERED SHOWERS AND THUNDERSTORMS. CAPES WILL BE LESS THAN 500 J/KG...SO EXPECT STORMS TO STAY BELOW SEVERE THRESHOLDS. LOWERED HIGH TEMPERATURES A FEW DEGREES DUE TO THE CLOUDINESS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 256 PM MDT TUE MAY 12 2015 WEAK QG ASCENT SHOULD STILL BE IMPACTING MUCH OF THE CWA AT 00Z THURSDAY AND WILL GRADUALLY TRANSITION TO SUBSIDENCE OVERNIGHT AS UPPER LEVEL RIDGING MOVES IN. THIS WILL ALLOW THURSDAY TO HAVE LOWER POPS ALTHOUGH PROBABLY NOT COMPLETELY ZERO...ESPECIALLY IN THE MOUNTAINS. THE NEXT WAVE AND QG ASCENT BEGINS IN THE MORE SOUTHERLY FLOW ON FRIDAY WHICH SHOULD ALLOW FOR A BIT MORE SHOWER COVERAGE IN THE MOUNTAINS DURING THE NORMAL DIURNAL TIMES BUT STILL NOTHING TREMENDOUS. SHOWER ACTIVITY ON THE PLAINS WILL BE BATTLING A LACK OF UPSLOPE SO PRECIPITATION THERE WILL BE SPOTTY AT BEST. THE SYSTEM FOR SATURDAY IS LOOKING A BIT LESS PROMISING THAN EARLIER. SOME SPREAD IN THE SOLUTIONS OF THE UPPER LOW POSITION BUT THE MODELS ARE SHOWING SOME QG ASCENT OVER THE CWA ALONG WITH LIGHT QPF. AGAIN...NOTHING TERRIBLY NOTEWORTHY. STRONG QG SUBSIDENCE IS FORECAST ON SUNDAY ALONG WITH A PUSH OF LOW LEVEL HIGH PRESSURE FROM THE NORTH WHICH MAY PUT A SIGNIFICANT DAMPER ON THE PRECIPITATION THREAT SUNDAY. THE UPPER RIDGE MOVES EAST OF COLORADO ON MONDAY FOR A SLIGHT INCREASE IN CONVECTIVE ACTIVITY BY TUESDAY. ALL IN ALL AT THIS TIME IT APPEARS THAT THERE IS A RATHER LOW RISK OF HEAVY PRECIPITATION THAT COULD WORSEN THE FLOODING SITUATION. MOREOVER...TEMPERATURES WILL REMAIN ON THE COOL SIDE WHICH WILL LESSEN THE MELTING OF THE SNOWPACK. && .AVIATION...(FOR THE TAFS THROUGH 00Z WEDNESDAY LATE AFTERNOON) ISSUED AT 256 PM MDT TUE MAY 12 2015 VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH WEDNESDAY. ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED 22-03Z TODAY. ANOTHER ROUND OF AFTERNOON THUNDERSTORMS ARE EXPECTED FOR WEDNESDAY...LIKELY A LITTLE EARLIER. THE STORMS WILL BE CAPABLE OF PRODUCING WIND GUSTS TO 35 KNOTS...BRIEF HEAVY RAIN AND SMALL HAIL. OUTSIDE OF OUTFLOW WINDS FROM THUNDERSTORMS...WINDS WILL BE SOUTHERLY AT KAPA AND KDEN. THROUGH WEDNESDAY. A WEAK DENVER CYCLONE MAY CAUSE WINDS TO TURN NORTHWESTERLY AFTER 12Z WEDNESDAY AT KDEN. && .HYDROLOGY... ISSUED AT 256 PM MDT TUE MAY 12 2015 THE SOUTH PLATTE RIVER IS CRESTING OVER WESTERN MORGAN COUNTY. THE CREST IS EXPECTED TO MOVE DOWN STREAM THROUGH MORGAN COUNTY THE NEXT 24 HOURS. FORECAST CRESTS HAVE BEEN SLIGHTLY LOWERED THIS MORNING ALONG THE SOUTH PLATTE RIVER. ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS EVENING AND WEDNESDAY AFTERNOON AND EVENING. BRIEF HEAVY RAIN IS POSSIBLE WITH THE THUNDERSTORMS. BEST CHANCE FOR HEAVY RAIN WILL BE WEDNESDAY AFTERNOON WHERE UP TO AN INCH WILL BE POSSIBLE UNDER THE STRONGEST STORMS. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...MEIER LONG TERM...ET AVIATION...MEIER HYDROLOGY...MEIER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1040 AM MDT TUE MAY 12 2015 .UPDATE... ISSUED AT 1040 AM MDT TUE MAY 12 2015 THE LATEST HRRR ...ARW...NMM AND NAM SHOW THE BEST CHANCE FOR SHOWERS AND STORMS ALONG THE FRONT RANGE FROM DENVER TO GREELEY TO FORT MORGAN. WILL INCREASE POPS INTO THE SCATTERED RANGE FOR THIS. WITH THE DRY LOW LEVELS...THE CONVECTION WILL PRODUCE GUSTY OUTFLOW WINDS. ANY HEAVY RAIN WILL BE LOCALIZED AND LIKELY LESS THAN A HALF INCH. NO OTHER CHANGES TO THE FORECAST ARE PLANNED. && .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 419 AM MDT TUE MAY 12 2015 UPPER RIDGE IS SHIFTING EAST OF COLORADO WITH SURFACE HIGH PRESSURE ON THE PLAINS. HIGH LEVEL MOISTURE MOVING ACROSS IN SOUTHWEST FLOW ALOFT...WHILE LOW LEVELS REMAIN DRY. LOOKING LIKE THERE WILL BE SOME DECREASE IN THE HIGH LEVEL MOISTURE LATER TODAY...BUT CONVECTION WILL LIKELY OFFSET THAT. STICKING WITH THE FORECAST OF SCATTERED CONVECTION OVER THE MOUNTAINS...WITH ISOLATED STORMS WORKING ONTO THE PLAINS LATE IN THE DAY. WITH CAPES EXPECTED TO BE 500-1000 J/KG OVER THE MOUNTAINS AND DRY LOW LEVELS...SOME OF THE STORMS WILL LIKELY PRODUCE GUSTY WINDS BUT WITH LIMITED FLOW ALOFT NOT TOO MUCH OF A SEVERE THREAT. THE PLAINS WILL BE WEAKLY CAPPED MOST OF THE DAY...MOST LIKELY CONVECTION WILL BE ON OUTFLOWS FROM THE MOUNTAIN CONVECTION. ANY SIGNIFICANT RAIN SHOULD BE ON A SMALL SCALE SO NOT MUCH IMPACT TO CURRENT RIVER CONDITIONS. I ONLY MADE MINOR ADJUSTMENTS TO THE FORECAST...INCREASING CLOUDS THIS MORNING AND ADDING A BIT MORE WIND ON THE PLAINS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 419 AM MDT TUE MAY 12 2015 STARTING WEDNESDAY MORNING A SHORTWAVE TROUGH WILL MOVE NORTH OUT OF THE DESERT SOUTHWEST ACROSS EASTERN COLORADO. MOISTURE AND PRECIPITATION WILL MOVE INTO THE MOUNTAINS FIRST WITH A LEE SIDE TROUGH DOMINATING THE NE COLORADO PLAINS. THROUGH THE DAY WEDNESDAY WITH THE INCREASE OF INSTABILITY FROM HEATING AND MOISTURE AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. PERIODS OF HEAVIER RAIN WILL BE POSSIBLE UNDER THE STRONGER STORMS...ESPECIALLY OVER THE EASTERN PLAINS. SNOW IN THE MOUNTAINS ABOVE 10000FT WILL BE POSSIBLE WITH LIGHT ACCUMULATIONS ON WEDNESDAY. TEMPERATURES ON WEDNESDAY WILL BE SLIGHTLY COOLER WITH HIGHS IN THE UPPER 60S. THE TROUGH WILL CONTINUE TO MOVE NORTH ON THURSDAY WITH SURFACE HIGH PRESSURE PUSHING INTO WESTERN COLORADO AND A LEE TROUGH FORMING OVER EASTERN COLORADO. UPPER LEVEL RIDGING THURSDAY WILL HELP DRY OUT CONDITIONS BRINGING ANOTHER SHORT REPRIEVE FROM RAIN. TEMPERATURES THURSDAY WILL BOUNCE BACK TO SEASONAL NORMALS WITH HIGHS REACHING INTO THE MID 70S. MODELS ARE CURRENTLY IN DECENT AGREEMENT REGARDING THE NEXT SYSTEM FORMING OFF THE COAST OF CALIFORNIA BY THURSDAY EVENING. UPPER LEVEL FLOW WILL BE STRONG FROM THE SOUTHWEST. SEVERAL EMBEDDED DISTURBANCES WILL KEEP A STEADY STREAM OF MOISTURE MOVING INTO COLORADO THAT WILL HELP BRING A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS TO THE NE REGION. FOR FRIDAY...TEMPERATURES REACH INTO THE UPPER 70S WITH INCREASED CAPE VALUES ALONG THE KS BORDER ALONG WITH A SHARP DRY LINE THAT COULD AID IN STRONG THUNDERSTORM DEVELOPMENT FOR FRIDAY AFTERNOON AND EVENING. ON SATURDAY AND SUNDAY THE UPPER LEVEL LOW WILL CONTINUE TO MAKE ITS EASTWARD PROGRESSION WITH STEADY MOISTURE OVER THE MOUNTAINS AND PLAINS THROUGH THE WEEKEND. TEMPERATURES WILL DIP BACK TO JUST BELOW NORMALS WITH HIGHS ONLY GETTING INTO THE MID TO UPPER 60S. THE SYSTEM LIFTS OUT TO THE NORTHEAST BY MONDAY EVENING BRINGING UPPER LEVEL RIDGING AND WARMER TEMPERATURES FOR TUESDAY. && .AVIATION...(FOR THE TAFS THROUGH 18Z WEDNESDAY MORNING) ISSUED AT 1040 AM MDT TUE MAY 12 2015 VFR THROUGH WEDNESDAY. ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED BETWEEN 21Z AND 03Z WITH THE MAIN THREAT BEING GUSTY WINDS TO AROUND 30 KNOTS. WINDS AT KAPA WILL MAINLY BE FROM THE SOUTH...WHILE KDEN WILL BE EAST TO SOUTHEAST. A WEAK DENVER CYCLONE PRODUCED A LIGHT THIS MORNING AND MAY AGAIN LATE TONIGHT AND WEDNESDAY MORNING. && .HYDROLOGY... ISSUED AT 419 AM MDT TUE MAY 12 2015 MAIN CREST ON THE SOUTH PLATTE IS MOVING INTO MORGAN COUNTY...WITH A SERIES OF SMALLER RISES PRECEDING IT. LITTLE CHANGE TO THE RIVER FORECAST AS MODERATE TO MAJOR FLOODING IS EXPECTED DOWNSTREAM TO STERLING THROUGH FRIDAY...AND MINOR TO MODERATE FLOODING BETWEEN STERLING AND JULESBURG THIS WEEKEND. WE WILL NEED TO WATCH ANY ADDITIONAL RAINFALL...THE FIRST OPPORTUNITY IS WEDNESDAY AFTERNOON AND EVENING WHICH LOOKS LIGHT OVERALL BUT THERE COULD BE SOME LOCALIZED HEAVIER RAIN OF UP TO AN INCH. THAT WOULD EXACERBATE LOCAL PROBLEMS... BUT PROBABLY NOT MUCH INFLUENCE ON THE PLATTE FLOODING. THERE MAY BE BETTER COVERAGE OF THUNDERSTORMS WITH ADDITIONAL RAINFALL OVER THE WEEKEND...NOT MUCH INDICATION OF ANY HEAVY RAINFALL HOWEVER. CLOSER TO THE FRONT RANGE STREAMS WILL REMAIN HIGH INDEFINITELY WITH SATURATED SOILS AND INCREASING SNOWMELT WITH THE WARMER TEMPERATURES. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MEIER SHORT TERM...GIMMESTAD LONG TERM...BOWEN AVIATION...MEIER HYDROLOGY...GIMMESTAD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
152 AM EDT TUE MAY 12 2015 .SYNOPSIS... ANOTHER MILD AND HUMID NIGHT WITH DENSE FOG TONIGHT GIVES WAY TO ANOTHER WARM DAY WITH SOME SHOWERS AND THUNDERSTORMS POSSIBLE IN THE AFTERNOON AS THE REMNANTS OF ANA PASS BY. LARGE HIGH PRESSURE WILL BUILD ACROSS THE EASTERN U.S. WITH DRIER WEATHER THROUGH THE REMAINDER OF THE WEEK. AN APPROACHING WARM FRONT COULD BRING SCATTERED SHOWERS NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 150 AM UPDATE... A FEW SHOWERS HAVE DEVELOPED ACROSS NE CT THROUGH SE MA EARLY THIS MORNING. ADDITIONAL SHOWERS S OF LONG ISLAND ASSOCD WITH ANA REMNANTS WILL BE LIFTING N ACROSS THE COASTAL PLAIN THROUGH DAYBREAK. AN ISOLD TSTM IS POSSIBLE AS ELEVATED INSTABILITY PARAMETERS ARE MARGINAL. CONVECTIVE LINE MOVING THROUGH CENTRAL NY IS EXPECTED TO REMAIN WEST OF SNE THROUGH DAYBREAK. PREVIOUS DISCUSSION... BACKDOOR FRONT APPEARS TO HAVE STALLED FROM NE RI THROUGH PORTIONS OF SE MA. TEMPS IN THE 50S TO THE N AND E OF THE FRONT AND MAINLY 60S JUST TO THE S AND W. AS REMNANTS OF ANA APPROACHES LATE TONIGHT...HI-RES GUIDANCE LIFTS THE FRONT BACK TO THE N OVERNIGHT ACROSS RI AND SE MA. AREAS OF DENSE FOG HAVE OVERSPREAD THE IMMEDIATE S COAST THIS EVENING. WITH LOW LEVEL S/SW FLOW EXPECT DENSE FOG THREAT WILL BE CONFINED TO THE S COAST AND SE MA...AND ALONG NE MA COAST WHERE WINDS ARE EASTERLY. LATEST HRRR HAS LOWEST VSBYS ALONG THE S AND E COASTS SO WE TRIMMED THE DENSE FOG ADVISORY AWAY FROM THE COAST. FINALLY...HAVE INCREASED POPS ACROSS SE COASTAL MA AND CAPE COD FOR LATE TONIGHT AS REMNANTS OF ANA TRACK TO THE SOUTH. MODELS SHOW AREA OF DEEPER MOISTURE ALONG WITH SOME ELEVATED INSTABILITY AT THE NOSE OF A LOW LEVEL JET WHICH SHOULD BRING AN AREA OF SHOWERS OR AN ISOLD TSTM TO SE COASTAL NEW ENG. LATEST RAP SHOWS AN AREA OF MEASURABLE RAINFALL LATE TONIGHT OVERSPREADING PORTIONS OF RI AND SE MA. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... TOMORROW... THE EARLY MORNING WILL BE MARKED BY A FAIRLY ROBUST DECK OF LOW LVL CLOUDS AND FOG POSSIBLY AS FAR WEST AS THE CT VALLEY. THIS WILL TAKE SOME TIME TO BURN OFF DURING THE MORNING AS DIURNAL MIXING COMMENCES. EXACTLY HOW QUICKLY WILL DETERMINE THE THREAT FOR CONVECTION/SEVERITY AS A COLD FRONT APPROACHES FOR THE AFTERNOON. BY AFTERNOON...AS THE FRONT MAKES IT/S PASS/APPROACH...SOME BREAKS OF SUN ARE LIKELY ESPECIALLY FOR INTERIOR NRN MA AND WRN CT. THIS AREA WILL BE THE PLACE TO WATCH AS BUFKIT PROFILES SHOW MODEST CAPE VALUES APPROACHING 1000-1500 J/KG COMBINED WITH ABOUT 30 KT OF 0-3KM SHEAR. UPPER LVL PROFILES WILL BE DRYING HOWEVER RATHER QUICKLY SO IT/S A RACE AGAINST TIME AS TO WHETHER THE DRY AIR OR INSTABILITY WINS AS THE LOW LVL F-GEN SOURCE APPROACHES. HI-RES AND EVEN MORE COARSE GUIDANCE ALL SHOWING THE POSSIBILITY OF AFTERNOON CONVECTIVE ACTIVITY WITH THE FROPA...ESPECIALLY NRN INTERIOR MA AWAY FROM WHERE THE LOW LVL CLOUDS WILL HOLD IN. SLIGHT CHANCE OF A STRONG STORM GIVEN THE MODEST SHEAR VALUES...WHICH COINCIDES WELL WITH THE 18Z DAY TWO SWODY FROM SPC...WHICH HIGHLIGHTS A MARGINAL RISK. THERE WILL STILL BE SOME LEFTOVER LOW-LVL MOISTURE FROM ANA AHEAD OF THE FRONT...SO WILL ALSO NEED TO WATCH FOR HEAVIER RAIN. OTHER ISSUES FOR TOMORROW... FIRE WEATHER CONCERNS... AREAS WHERE THE CLOUD DISSIPATE WILL SEE LOW RELATIVE RH VALUES AND GIVEN DIURNAL MIXING...WIND GUSTS OF 25-30 MPH AT TIMES. THEREFORE...HAVE A MARGINAL RISK OF ELEVATED FIRE WEATHER DURING THE DAY IN SPITE OF THE T-STORM/SHRA POTENTIAL. FOR MORE ON THIS...SEE THE FIRE WEATHER SECTION BELOW. HIGH SURF... THE REMNANTS OF ANA WILL BRING 6 TO 10 FOOT SWELL TO OUR SOUTHERN COASTAL WATERS TOMORROW. THIS WILL BRING HIGH SURF AND DANGEROUS RIP CURRENTS TO OUR OCEAN EXPOSED SOUTH FACING BEACHES ON TUE. GIVEN RELATIVELY WARM TEMPS EXPECTED...WE MAY STILL HAVE TO CONSIDER A HIGH SURF ADVISORY EVEN THOUGH THE SUMMER SEASON HAS NOT OFFICIAL BEGUN. TUESDAY NIGHT... FINALLY...THE HIGHER DWPTS...DRIER AIR AND IMPROVING CONDITIONS WILL BE MOVING ACROSS THE REGION FROM W-E DURING THE OVERNIGHT HOURS. LEFTOVER TSRA/SHRA WILL GENERALLY DIMINISH WITH THE LOSS OF DIURNAL HEATING...SO THERE MAY BE A FEW CLOUDS STILL TO CONTEND WITH EARLY. GIVEN THE MASS FIELDS ALSO SUPPORT A MODERATE PRES GRADIENT...TEMPS ARE NOT LIKELY TO FALL AS LOW AS THEIR POTENTIAL DESPITE THE DROPPING DWPTS. MINS MAINLY IN THE MID 40S AND LOW 50S. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * BREAK IN THE HEAT ON WEDNESDAY WITH NORMAL TEMPS * HIGH PRESSURE ON THURS & FRI KEEP CONDITIONS DRY * RAIN RELIEF POSSIBLE OVER THE WEEKEND WITH APPROACHING LOW OVERVIEW... FORECAST GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT FOR MOST OF THE EXTENDED. NOTICED 11.12Z GUIDANCE LEANED TOWARDS THE 11.00Z GFS FROM LAST NIGHT IN BRINGING PRECIP INTO THE REGION FOR THE WEEKEND. OTHERWISE BY LATE WEEKEND INTO EARLY NEXT WEEK APPEARS THAT THE EC IS MORE AMPLIFIED IN BUILDING A STOUT RIDGE OVER NEW ENGLAND COMPARED TO THE GFS. THIS COULD MAKE THINGS LESS STORMY THEN PREVIOUSLY THOUGHT. APPEARS TEMPS WILL LEAN MORE TOWARDS OR JUST ABOVE NORMAL OVER THE LONG TERM. COULD SEE AN INCREASE IN THE HEAT BY NEXT WEEK. DETAILS... * WEDNESDAY...HIGH CONFIDENCE. SECONDARY COLD FRONT WILL PASS THROUGH THE REGION PUSHING UPPER LEVEL TROUGH OFFSHORE AND TEMPS ALOFT TO COOL OVER THE AREA. WINDS WILL SWITCH TO A MORE NW FLOW...ALLOWING FOR GOOD DOWNSLOPING. PARTLY SUNNY SKIES WILL ALLOW FOR TEMPS TO WARM INTO THE UPPER 60S...WHICH IS NEAR NORMAL! DID LOWER DEWPOINTS AND INCREASE WIND GUSTS VERSUS GUIDANCE AS MIXING ON WED WILL BE VERY GOOD. THIS WILL BRING A RISK OF FIRE WEATHER CONCERNS TO THE REGION. DETAILS IN THE FIRE WEATHER SECTION BELOW. BECAUSE OF THE FALLING TEMPS ALOFT AND MARGINAL MOISTURE FIELD... HAVE INSERTED A LOW CHANCE FOR AN ISOLATED SHOWER FOR FRANKLIN COUNTY. CONFIDENCE IS LOW...BUT CANNOT RULE IT OUT. TEMPS ALOFT WILL DROP THROUGHOUT THE DAY AND INTO THE OVERNIGHT HOURS. IN FACT 850MB COULD DROP DOWN TO 0C OVERNIGHT. THIS COMBINED WITH CLEAR SKIES AND DECOUPLE WINDS WILL ALLOW FOR RADIATIONAL COOLING OVERNIGHT. TEMPS WILL DROP INTO THE LOWER 40S. COULD SEE A FEW UPPER 30S BUT HAVE A LOW CONFIDENCE ON FROST DEVELOPMENT IN THE VALLEY LOCALS ACROSS THE NW PORTION OF THE AREA. * THURSDAY AND FRIDAY...HIGH CONFIDENCE. HIGH PRESSURE WILL MOVE RIGHT ON IN FOR THURSDAY AND LAST INTO FRIDAY. THIS WILL ALLOW FOR DRY WEATHER AND PLENTY OF SUNSHINE. HAVE AN INCREASE CHANCE THAT SEA BREEZES WILL DEVELOP ACROSS THE COASTLINES FOR BOTH DAYS. TEMPERATURES WILL WARM ABOVE AVERAGE ONCE AGAIN...WITH HIGHS IN THE LOW 70S ON THURSDAY AND MID 70S ON FRIDAY AWAY FROM THE COASTLINES. * THE WEEKEND...MODERATE CONFIDENCE. HIGH PRESSURE WILL MOVE SOUTH AND OFFSHORE ALLOWING FOR APPROACHING LOW PRESSURE FROM THE WEST TO PUSH A WARM FRONT OVER THE REGION. DEPENDING ON WHERE THIS WARM FRONT SETS UP WE COULD SEE A FEW ROUNDS OF SHOWERS AS A WAVE OR TWO MOVES THROUGH THE AREA. NOT EXPECTING A DROUGHT BUSTER AS WE NEED ABOUT 3-5 INCHES...BUT SOME RAIN RELIEF TO THE REGION IS ANTICIPATED. * MONDAY...LOW CONFIDENCE. MONDAY IS LOOKING WARM BUT STILL UNCERTAIN ON PRECIP CHANCES AS THE PATTERN WILL BE FOCUSED ON IF THE RIDGE WILL BUILD OR NOT. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. THROUGH 12Z...WIDESPREAD IFR/LIFR CONDITIONS IN STRATUS AND FOG...ALTHOUGH SOME MVFR IN THE CT VALLEY. DENSE FOG CONFINED TO THE S COAST. SCT SHOWERS AND ISOLD TSTM NE CT THROUGH SE MA. TODAY...MODERATE CONFIDENCE. IFR/LIFR STRATUS AND FOG WILL IMPROVE TO VFR BY MIDDAY...BUT AREAS OF IFR WILL LIKELY PERSIST ALONG THE IMMEDIATE S COAST AND ESPECIALLY THE ISLANDS INTO THE AFTERNOON. CHANCE OF A FEW THUNDERSTORMS IN THE AFTERNOON. SW GUSTS TO 25 KT POSSIBLE RI AND SE MA DURING THE AFTERNOON. TONIGHT...MODERATE CONFIDENCE. MAINLY VFR...BUT IFR CONDITIONS POSSIBLE INTO THE EVENING ACROSS OUTER CAPE/ISLANDS. WEDNESDAY...HIGH CONFIDENCE. VFR CIGS. NW GUSTS TO 25 KT. KBOS TAF...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN TIMING OF IMPROVEMENT TO VFR. KBDL TAF...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN TIMING OF IMPROVEMENT TO VFR. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...HIGH CONFIDENCE. THURSDAY-FRIDAY...VFR. LIGHT AND VARIABLE WINDS. SEA BREEZES POSSIBLE ON BOTH DAYS. SATURDAY...VFR/MVFR WITH AN INCREASE IN SHOWERS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY NIGHT/... TONIGHT INTO TOMORROW...MODERATE CONFIDENCE. LEFTOVER SWELL FROM ANA WILL BEGIN TO BUILD ALONG THE S COASTAL WATERS LATE. REACHING A PEAK OF ABOUT 7-9 FT BY THE MID DAY TOMORROW. SMALL CRAFT ADVISORIES CONTINUE FOR THIS THREAT. OTHERWISE...WINDS REMAIN GENERALLY OUT OF THE S-SW UNTIL A COLD FRONTAL PASSAGE TOMORROW LATE IN THE DAY...AT WHICH POINT THEY SHIFT W. THERE IS THE LOW THREAT FOR SOME THUNDERSTORMS...MAINLY ACROSS THE E WATERS LATE IN THE DAY TOMORROW. FOG/STRATUS WILL ONCE AGAIN YIELD NEAR ZERO VSBYS ACROSS THE WATERS TONIGHT INTO TOMORROW. TOMORROW NIGHT...HIGH CONFIDENCE. SLOW IMPROVEMENT AS WINDS SHIFT TO THE W. ANY SHOWERS/STORMS WILL END AND SCOUR OUT THE LEFTOVER FOG. SEAS WILL ALSO GRADUALLY DECLINE SUCH THAT SMALL CRAFT ADVISORIES MAY BE DROPPED BY THE EARLY MORNING HOURS. OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE. WEDNESDAY...LINGERING 5FT SEAS WILL CONTINUE ON WED. HOWEVER GUSTS WILL BE ON THE INCREASE TO 25 KTS ESP ACROSS THE INTERIOR WATERS...SCA WILL BE NEEDED. THURSDAY-FRIDAY...HIGH PRESSURE BUILDS OVER THE WATERS. WINDS AND SEAS WILL BE BELOW SMALL CRAFT CRITERIA. SATURDAY...WARM FRONT WILL PUSH OVER THE WATERS INCREASING PRECIP CHANCES. BUT BOTH WINDS AND SEAS WILL REMAIN BELOW SCA. && .FIRE WEATHER... TOMORROW...TEMPERATURES MAY RISE TO NEAR 90 IN THE LOWER CT VALLEY OF MA AND CT WITH DWPTS HOLDING IN THE 50S AND 60S. THERE IS THE POSSIBILITY THEREFORE...THAT MIN RH VALUES WILL FALL TO AROUND 25-35 PERCENT IN PORTIONS OF SW MA DURING THE DAY. SW WINDS WILL GUST 25-30 MPH AT TIMES BY THE AFTERNOON. ALSO...THERE IS THE THREAT FOR THUNDERSTORMS AND ACCUMULATING RAINFALL...BUT THESE WILL GENERALLY BE HIT OR MISS AND WILL NOT PROVIDE THE WIDESPREAD RAINFALL THAT MUCH OF THE REGION REQUIRES. A FIRE WEATHER WATCH WILL BE ISSUED FOR SW PORTIONS OF MA DUE TO THE COLLOCATION OF DRIEST RH VALUES...HIGHEST WINDS AND LOWEST THREAT FOR RAINFALL. WEDNESDAY...A HIGHER RISK FOR FIRE WEATHER DEVELOPMENT IS EXPECTED ON WEDNESDAY...HOWEVER IT WILL BE DEPENDENT ON PRECIP CHANCES OVER THE NEXT 24-48 HOURS. SECONDARY COLD FRONT WILL PUSH THROUGH WED MORNING ALLOWING FOR WINDS TO BE MORE OUT OF THE NW. THIS WILL ALLOW FOR A DOWNSLOPING EFFECT...WHICH WILL INCREASE THE WIND GUSTS AND LOWER DEWPOINTS. RIGHT NOW BELIEVE THAT RH VALUES WILL DROP TO AROUND 30 PERCENT ACROSS MUCH OF THE REGION WITH NW WINDS GUSTING TO NEAR 30 MPH. ONLY DIFFERENCE COMPARED TO THE PREVIOUS DAYS IS HIGH TEMPS WILL WARM ONLY INTO THE UPPER 60S. HOWEVER APPEARS THAT THERE WILL BE A GOOD AMOUNT OF SUNSHINE ACROSS MOST OF THE REGION. WILL NEED TO CONTINUE TO MONITOR WEDNESDAY FOR POSSIBLE HEADLINES. THURSDAY AND FRIDAY...DRY WEATHER CONDITIONS WILL CONTINUE WITH RH VALUES DROPPING WELL INTO THE 20 PERCENT LEVEL AND WITH FULL SHINE. SINCE HIGH PRESSURE WILL BE OVERHEAD WIND WILL BE LIGHT AND VARIABLE...GUSTS COULD REACH 10-15 MPH. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MAZ018>024. FIRE WEATHER WATCH FROM NOON EDT TODAY THROUGH THIS EVENING FOR MAZ008>012. RI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR RIZ005>008. MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ254>256. && $$ SYNOPSIS...DOODY/DUNTEN NEAR TERM...KJC SHORT TERM...DOODY LONG TERM...DUNTEN AVIATION...KJC/DUNTEN MARINE...DOODY/DUNTEN FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1222 PM CDT TUE MAY 12 2015 .UPDATE... ISSUED AT 943 AM CDT TUE MAY 12 2015 MAIN STRATOCUMULUS SHIELD BASICALLY MADE IT DOWN TO THE I-74 CORRIDOR WITH SOME SCATTERED CLOUDS AS FAR SOUTH AS MATTOON AND LAWRENCEVILLE...BUT THESE SHOULD CONTINUE TO PULL BACK NORTHWARD THROUGH MIDDAY. HOWEVER...LATEST RAP GUIDANCE SUGGESTS THE CLOUDS HOLDING ON A BIT LONGER AROUND CHAMPAIGN AND DANVILLE. CURRENTLY SEEING SOME WIND GUSTS OF 25-30 MPH...WHICH SHOULD CONTINUE INTO MID AFTERNOON. TEMPERATURES CURRENTLY ON TRACK AND ONLY REQUIRED SOME MINOR TWEAKS. UPDATES TO THE ZONES/GRIDS WERE MAINLY DONE FOR THE SKY COVER AND WIND TRENDS. && .SHORT TERM...(TODAY) ISSUED AT 329 AM CDT TUE MAY 12 2015 07Z/2AM SURFACE ANALYSIS SHOWS 1001MB LOW OVER THE NORTHERN GREAT LAKES WHILE A 1025MB HIGH BUILDS INTO THE CENTRAL PLAINS. PRESSURE GRADIENT BETWEEN THESE TWO FEATURES WILL REMAIN TIGHT ENOUGH TO PRODUCE BRISK WESTERLY WINDS ACROSS CENTRAL ILLINOIS TODAY. SUSTAINED WINDS WILL GENERALLY BE IN THE 10 TO 15 MPH RANGE...BUT GUSTS COULD REACH 25 TO 30 MPH AS MIXING TAKES PLACE LATER THIS MORNING. LATEST VWP NETWORK SHOWS 925MB WINDS OF 40 TO 45 MPH AND THINK SOME OF THIS HIGHER MOMENTUM AIR WILL GET MIXED DOWN TO THE SURFACE ONCE MORNING INVERSION IS BROKEN. PRESSURE GRADIENT WILL TEND TO RELAX AS THE DAY PROGRESSES...SO GUSTS WILL BEGIN TO SLOWLY SUBSIDE BY MID-AFTERNOON. LOW CLOUDS CURRENTLY ALONG/NORTH OF A RUSHVILLE TO BLOOMINGTON LINE WILL LIFT NORTHEASTWARD AND CLEAR OUT OF THE AREA BY MID-MORNING...FOLLOWED BY MOSTLY SUNNY SKIES ACROSS THE BOARD FOR THE REMAINDER OF THE DAY. AFTERNOON HIGH TEMPERATURES WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS...WITH READINGS ONLY RISING INTO THE LOWER TO MIDDLE 60S. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 329 AM CDT TUE MAY 12 2015 HIGH PRESSURE WILL BUILD EASTWARD INTO THE MIDWEST TONIGHT...WITH THE RIDGE AXIS EXPECTED TO BE POSITIONED RIGHT OVER ILLINOIS BY 12Z WED. CLEAR SKIES AND LIGHT WINDS BENEATH THE RIDGE WILL ALLOW EXCELLENT RADIATIONAL COOLING OF THE DRY AIRMASS TO TAKE PLACE...RESULTING IN OVERNIGHT LOW TEMPERATURES IN THE LOWER TO MIDDLE 40S. MAY EVEN SEE A FEW UPPER 30S IN FAVORED LOW-LYING RURAL AREAS. THE HIGH WILL BEGIN TO SHIFT OFF TO THE EAST ON WEDNESDAY...HOWEVER LOW-LEVEL FLOW WILL MAINTAIN A DISTINCT EASTERLY COMPONENT. AS A RESULT...HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE IN THE UPPER 60S TO AROUND 70 DEGREES. UPPER HEIGHTS BEGIN TO RISE SIGNIFICANTLY BY THURSDAY AS DEEP UPPER LOW OVER THE GULF OF ALASKA DROPS SOUTHEASTWARD AND REACHES THE CALIFORNIA COAST...RESULTING IN DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN CONUS. A WEAK DISTURBANCE NOTED ON LATEST WATER VAPOR IMAGERY OFF THE COAST OF SOUTHERN CALIFORNIA WILL GET EJECTED NORTHEASTWARD BY THE DIGGING WEST COAST TROUGH...WITH THIS FEATURE TRACKING INTO THE GREAT LAKES BY FRIDAY. MODELS ARE IN GOOD AGREEMENT WITH THE TRACK AND TIMING OF THIS WAVE...WITH SOME MINOR DISCREPANCIES ON HOW QUICKLY TO SPREAD PRECIP INTO ILLINOIS. GIVEN INITIALLY VERY DRY AIRMASS IN PLACE BENEATH THE SURFACE HIGH...PREFER A SLOWER ARRIVAL OF PRECIP. AS A RESULT...HAVE GONE WITH A DRY FORECAST THROUGH THURSDAY MORNING EAST OF I-55 WITH LOW CHANCE POPS DELAYED UNTIL AFTERNOON. FURTHER WEST...RAIN CHANCES WILL INCREASE TO LIKELY ACROSS THE ILLINOIS RIVER VALLEY BY AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS MUCH OF THE AREA THURSDAY NIGHT...WITH THE BEST RAIN CHANCES FOCUSED NORTH OF THE I-70 CORRIDOR. ONCE THE SHORT-WAVE SHIFTS INTO THE GREAT LAKES...FORCING FOR ADDITIONAL PRECIP BECOMES MUCH WEAKER FRIDAY AND SATURDAY. SEVERAL MODELS ARE HINTING THAT ANOTHER WEAK WAVE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW MAY ENHANCE SHOWERS ACROSS SOUTHERN ILLINOIS INTO THE OHIO RIVER VALLEY...HOWEVER VERY LITTLE FOCUS FOR ORGANIZED CONVECTION EXISTS FURTHER NORTH ACROSS THE REMAINDER OF THE AREA. AS A RESULT...WILL ONLY CARRY LOW CHANCE POPS THROUGH THE PERIOD. DEEP UPPER LOW OVER CALIFORNIA WILL GRADUALLY EJECT NORTHEASTWARD LATE IN THE WEEKEND. MODELS ARE IN GOOD AGREEMENT WITH THIS PROCESS THROUGH 144 HOURS...THEN SOLUTIONS BEGIN TO DIVERGE AFTER THAT. BOTH THE GFS AND ECMWF SHOW THE LOW TRACKING INTO THE DAKOTAS BY SUNDAY EVENING...WITH CONVECTION DEVELOPING ALONG A TRAILING COLD FRONT ACROSS THE PLAINS. THE ECMWF THEN BECOMES MORE PROGRESSIVE WITH THE WAVE...AS IT OPENS UP AND PUSHES EASTWARD INTO THE NORTHERN GREAT LAKES BY MONDAY. MEANWHILE...THE GFS KEEPS THE LOW CLOSED LONGER AND IS THUS SLOWER WITH ITS EASTWARD TRACK. THIS MAKES A BIG DIFFERENCE WITH TIMING OF ASSOCIATED COLD FRONT...AS GFS LINGERS THIS BOUNDARY AND RAIN CHANCES UNTIL TUESDAY. SINCE OVERALL SYNOPTIC PATTERN HAS BEEN PROGRESSIVE OVER THE PAST WEEK AND THE GEM SUPPORTS THE ECMWF...WILL BE GOING WITH THE FASTER ECMWF/GEM SOLUTION IN THE EXTENDED. AS A RESULT...WILL BRING LIKELY POPS INTO THE FAR WESTERN CWA SUNDAY AFTERNOON...THEN FURTHER EAST ACROSS THE REMAINDER OF THE AREA SUNDAY NIGHT. WILL THEN BEGIN TO SHIFT THE RAIN CHANCES OUT OF THE PICTURE ON MONDAY...WITH DRY WEATHER RETURNING MONDAY NIGHT AND TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1219 PM CDT TUE MAY 12 2015 THICKER STRATOCUMULUS AROUND 3500 FEET CONTINUES TO BREAK UP AND WILL BE MOST PROMINENT AT KCMI/KDEC FOR A COUPLE MORE HOURS. OTHERWISE...GENERAL TREND WILL BE VFR WITH SOME INCREASE IN HIGH CLOUDS LATER THIS AFTERNOON. GUSTY WEST/NORTHWEST WINDS AROUND 25 KNOTS SHOULD BE SETTLING DOWN AFTER ABOUT 23Z...AND WILL GRADUALLY TURN MORE THE NORTH/NORTHEAST OVERNIGHT AS AN AREA OF HIGH PRESSURE MOVES THROUGH THE MIDWEST. AS THE HIGH MOVES FURTHER EAST WEDNESDAY MORNING...WINDS WILL BECOME MORE EASTERLY AND INCREASE TO AROUND 10 KNOTS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...BARNES LONG TERM...BARNES AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
943 AM CDT TUE MAY 12 2015 .UPDATE... ISSUED AT 943 AM CDT TUE MAY 12 2015 MAIN STRATOCUMULUS SHIELD BASICALLY MADE IT DOWN TO THE I-74 CORRIDOR WITH SOME SCATTERED CLOUDS AS FAR SOUTH AS MATTOON AND LAWRENCEVILLE...BUT THESE SHOULD CONTINUE TO PULL BACK NORTHWARD THROUGH MIDDAY. HOWEVER...LATEST RAP GUIDANCE SUGGESTS THE CLOUDS HOLDING ON A BIT LONGER AROUND CHAMPAIGN AND DANVILLE. CURRENTLY SEEING SOME WIND GUSTS OF 25-30 MPH...WHICH SHOULD CONTINUE INTO MID AFTERNOON. TEMPERATURES CURRENTLY ON TRACK AND ONLY REQUIRED SOME MINOR TWEAKS. UPDATES TO THE ZONES/GRIDS WERE MAINLY DONE FOR THE SKY COVER AND WIND TRENDS. && .SHORT TERM...(TODAY) ISSUED AT 329 AM CDT TUE MAY 12 2015 07Z/2AM SURFACE ANALYSIS SHOWS 1001MB LOW OVER THE NORTHERN GREAT LAKES WHILE A 1025MB HIGH BUILDS INTO THE CENTRAL PLAINS. PRESSURE GRADIENT BETWEEN THESE TWO FEATURES WILL REMAIN TIGHT ENOUGH TO PRODUCE BRISK WESTERLY WINDS ACROSS CENTRAL ILLINOIS TODAY. SUSTAINED WINDS WILL GENERALLY BE IN THE 10 TO 15 MPH RANGE...BUT GUSTS COULD REACH 25 TO 30 MPH AS MIXING TAKES PLACE LATER THIS MORNING. LATEST VWP NETWORK SHOWS 925MB WINDS OF 40 TO 45 MPH AND THINK SOME OF THIS HIGHER MOMENTUM AIR WILL GET MIXED DOWN TO THE SURFACE ONCE MORNING INVERSION IS BROKEN. PRESSURE GRADIENT WILL TEND TO RELAX AS THE DAY PROGRESSES...SO GUSTS WILL BEGIN TO SLOWLY SUBSIDE BY MID-AFTERNOON. LOW CLOUDS CURRENTLY ALONG/NORTH OF A RUSHVILLE TO BLOOMINGTON LINE WILL LIFT NORTHEASTWARD AND CLEAR OUT OF THE AREA BY MID-MORNING...FOLLOWED BY MOSTLY SUNNY SKIES ACROSS THE BOARD FOR THE REMAINDER OF THE DAY. AFTERNOON HIGH TEMPERATURES WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS...WITH READINGS ONLY RISING INTO THE LOWER TO MIDDLE 60S. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 329 AM CDT TUE MAY 12 2015 HIGH PRESSURE WILL BUILD EASTWARD INTO THE MIDWEST TONIGHT...WITH THE RIDGE AXIS EXPECTED TO BE POSITIONED RIGHT OVER ILLINOIS BY 12Z WED. CLEAR SKIES AND LIGHT WINDS BENEATH THE RIDGE WILL ALLOW EXCELLENT RADIATIONAL COOLING OF THE DRY AIRMASS TO TAKE PLACE...RESULTING IN OVERNIGHT LOW TEMPERATURES IN THE LOWER TO MIDDLE 40S. MAY EVEN SEE A FEW UPPER 30S IN FAVORED LOW-LYING RURAL AREAS. THE HIGH WILL BEGIN TO SHIFT OFF TO THE EAST ON WEDNESDAY...HOWEVER LOW-LEVEL FLOW WILL MAINTAIN A DISTINCT EASTERLY COMPONENT. AS A RESULT...HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE IN THE UPPER 60S TO AROUND 70 DEGREES. UPPER HEIGHTS BEGIN TO RISE SIGNIFICANTLY BY THURSDAY AS DEEP UPPER LOW OVER THE GULF OF ALASKA DROPS SOUTHEASTWARD AND REACHES THE CALIFORNIA COAST...RESULTING IN DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN CONUS. A WEAK DISTURBANCE NOTED ON LATEST WATER VAPOR IMAGERY OFF THE COAST OF SOUTHERN CALIFORNIA WILL GET EJECTED NORTHEASTWARD BY THE DIGGING WEST COAST TROUGH...WITH THIS FEATURE TRACKING INTO THE GREAT LAKES BY FRIDAY. MODELS ARE IN GOOD AGREEMENT WITH THE TRACK AND TIMING OF THIS WAVE...WITH SOME MINOR DISCREPANCIES ON HOW QUICKLY TO SPREAD PRECIP INTO ILLINOIS. GIVEN INITIALLY VERY DRY AIRMASS IN PLACE BENEATH THE SURFACE HIGH...PREFER A SLOWER ARRIVAL OF PRECIP. AS A RESULT...HAVE GONE WITH A DRY FORECAST THROUGH THURSDAY MORNING EAST OF I-55 WITH LOW CHANCE POPS DELAYED UNTIL AFTERNOON. FURTHER WEST...RAIN CHANCES WILL INCREASE TO LIKELY ACROSS THE ILLINOIS RIVER VALLEY BY AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS MUCH OF THE AREA THURSDAY NIGHT...WITH THE BEST RAIN CHANCES FOCUSED NORTH OF THE I-70 CORRIDOR. ONCE THE SHORT-WAVE SHIFTS INTO THE GREAT LAKES...FORCING FOR ADDITIONAL PRECIP BECOMES MUCH WEAKER FRIDAY AND SATURDAY. SEVERAL MODELS ARE HINTING THAT ANOTHER WEAK WAVE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW MAY ENHANCE SHOWERS ACROSS SOUTHERN ILLINOIS INTO THE OHIO RIVER VALLEY...HOWEVER VERY LITTLE FOCUS FOR ORGANIZED CONVECTION EXISTS FURTHER NORTH ACROSS THE REMAINDER OF THE AREA. AS A RESULT...WILL ONLY CARRY LOW CHANCE POPS THROUGH THE PERIOD. DEEP UPPER LOW OVER CALIFORNIA WILL GRADUALLY EJECT NORTHEASTWARD LATE IN THE WEEKEND. MODELS ARE IN GOOD AGREEMENT WITH THIS PROCESS THROUGH 144 HOURS...THEN SOLUTIONS BEGIN TO DIVERGE AFTER THAT. BOTH THE GFS AND ECMWF SHOW THE LOW TRACKING INTO THE DAKOTAS BY SUNDAY EVENING...WITH CONVECTION DEVELOPING ALONG A TRAILING COLD FRONT ACROSS THE PLAINS. THE ECMWF THEN BECOMES MORE PROGRESSIVE WITH THE WAVE...AS IT OPENS UP AND PUSHES EASTWARD INTO THE NORTHERN GREAT LAKES BY MONDAY. MEANWHILE...THE GFS KEEPS THE LOW CLOSED LONGER AND IS THUS SLOWER WITH ITS EASTWARD TRACK. THIS MAKES A BIG DIFFERENCE WITH TIMING OF ASSOCIATED COLD FRONT...AS GFS LINGERS THIS BOUNDARY AND RAIN CHANCES UNTIL TUESDAY. SINCE OVERALL SYNOPTIC PATTERN HAS BEEN PROGRESSIVE OVER THE PAST WEEK AND THE GEM SUPPORTS THE ECMWF...WILL BE GOING WITH THE FASTER ECMWF/GEM SOLUTION IN THE EXTENDED. AS A RESULT...WILL BRING LIKELY POPS INTO THE FAR WESTERN CWA SUNDAY AFTERNOON...THEN FURTHER EAST ACROSS THE REMAINDER OF THE AREA SUNDAY NIGHT. WILL THEN BEGIN TO SHIFT THE RAIN CHANCES OUT OF THE PICTURE ON MONDAY...WITH DRY WEATHER RETURNING MONDAY NIGHT AND TUESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 600 AM CDT TUE MAY 12 2015 VFR CIGS EXPECTED TO PUSH OFF TO OUR EAST THIS MORNING BASED ON CURRENT TRENDS IN SATELLITE DATA AND LATEST FORECAST SOUNDINGS. CIG BASES HAVE BEEN FROM 3500 TO 4500 FEET WITH SOME LOWER...MVFR CIGS...NOTED TO OUR NORTHWEST AND NORTH. THOSE ARE EXPECTED TO REMAIN JUST TO THE NORTH OF PIA AND BMI THIS MORNING. SPI...DEC AND CMI HAVE BEEN RIGHT ON THE EDGE OF THE VFR CIGS AND EXPECT THOSE AREAS TO SEE SOME SCT-BKN CIGS FOR A TIME THIS MORNING WITH THE MAIN AREA OF OVR CIGS TO THE NORTH. GUSTY WINDS WILL CONTINUE TODAY WITH FORECAST SOUNDINGS SUGGESTING WIND GUSTS TO AROUND 25 KTS AT TIMES OUT OF THE WEST AND THEN NORTHWEST THIS AFTERNOON. LOOK FOR THE WINDS TO RAPIDLY DIMINISH JUST AFTER SUNSET AS HIGH PRESSURE SETTLES IN OVERNIGHT WITH VFR CONDITIONS CONTINUING. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...BARNES LONG TERM...BARNES AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
329 AM CDT TUE MAY 12 2015 .SHORT TERM...(TODAY) ISSUED AT 329 AM CDT TUE MAY 12 2015 07Z/2AM SURFACE ANALYSIS SHOWS 1001MB LOW OVER THE NORTHERN GREAT LAKES WHILE A 1025MB HIGH BUILDS INTO THE CENTRAL PLAINS. PRESSURE GRADIENT BETWEEN THESE TWO FEATURES WILL REMAIN TIGHT ENOUGH TO PRODUCE BRISK WESTERLY WINDS ACROSS CENTRAL ILLINOIS TODAY. SUSTAINED WINDS WILL GENERALLY BE IN THE 10 TO 15 MPH RANGE...BUT GUSTS COULD REACH 25 TO 30 MPH AS MIXING TAKES PLACE LATER THIS MORNING. LATEST VWP NETWORK SHOWS 925MB WINDS OF 40 TO 45 MPH AND THINK SOME OF THIS HIGHER MOMENTUM AIR WILL GET MIXED DOWN TO THE SURFACE ONCE MORNING INVERSION IS BROKEN. PRESSURE GRADIENT WILL TEND TO RELAX AS THE DAY PROGRESSES...SO GUSTS WILL BEGIN TO SLOWLY SUBSIDE BY MID-AFTERNOON. LOW CLOUDS CURRENTLY ALONG/NORTH OF A RUSHVILLE TO BLOOMINGTON LINE WILL LIFT NORTHEASTWARD AND CLEAR OUT OF THE AREA BY MID-MORNING...FOLLOWED BY MOSTLY SUNNY SKIES ACROSS THE BOARD FOR THE REMAINDER OF THE DAY. AFTERNOON HIGH TEMPERATURES WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS...WITH READINGS ONLY RISING INTO THE LOWER TO MIDDLE 60S. && .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 329 AM CDT TUE MAY 12 2015 HIGH PRESSURE WILL BUILD EASTWARD INTO THE MIDWEST TONIGHT...WITH THE RIDGE AXIS EXPECTED TO BE POSITIONED RIGHT OVER ILLINOIS BY 12Z WED. CLEAR SKIES AND LIGHT WINDS BENEATH THE RIDGE WILL ALLOW EXCELLENT RADIATIONAL COOLING OF THE DRY AIRMASS TO TAKE PLACE...RESULTING IN OVERNIGHT LOW TEMPERATURES IN THE LOWER TO MIDDLE 40S. MAY EVEN SEE A FEW UPPER 30S IN FAVORED LOW-LYING RURAL AREAS. THE HIGH WILL BEGIN TO SHIFT OFF TO THE EAST ON WEDNESDAY...HOWEVER LOW-LEVEL FLOW WILL MAINTAIN A DISTINCT EASTERLY COMPONENT. AS A RESULT...HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE IN THE UPPER 60S TO AROUND 70 DEGREES. UPPER HEIGHTS BEGIN TO RISE SIGNIFICANTLY BY THURSDAY AS DEEP UPPER LOW OVER THE GULF OF ALASKA DROPS SOUTHEASTWARD AND REACHES THE CALIFORNIA COAST...RESULTING IN DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN CONUS. A WEAK DISTURBANCE NOTED ON LATEST WATER VAPOR IMAGERY OFF THE COAST OF SOUTHERN CALIFORNIA WILL GET EJECTED NORTHEASTWARD BY THE DIGGING WEST COAST TROUGH...WITH THIS FEATURE TRACKING INTO THE GREAT LAKES BY FRIDAY. MODELS ARE IN GOOD AGREEMENT WITH THE TRACK AND TIMING OF THIS WAVE...WITH SOME MINOR DISCREPANCIES ON HOW QUICKLY TO SPREAD PRECIP INTO ILLINOIS. GIVEN INITIALLY VERY DRY AIRMASS IN PLACE BENEATH THE SURFACE HIGH...PREFER A SLOWER ARRIVAL OF PRECIP. AS A RESULT...HAVE GONE WITH A DRY FORECAST THROUGH THURSDAY MORNING EAST OF I-55 WITH LOW CHANCE POPS DELAYED UNTIL AFTERNOON. FURTHER WEST...RAIN CHANCES WILL INCREASE TO LIKELY ACROSS THE ILLINOIS RIVER VALLEY BY AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS MUCH OF THE AREA THURSDAY NIGHT...WITH THE BEST RAIN CHANCES FOCUSED NORTH OF THE I-70 CORRIDOR. ONCE THE SHORT-WAVE SHIFTS INTO THE GREAT LAKES...FORCING FOR ADDITIONAL PRECIP BECOMES MUCH WEAKER FRIDAY AND SATURDAY. SEVERAL MODELS ARE HINTING THAT ANOTHER WEAK WAVE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW MAY ENHANCE SHOWERS ACROSS SOUTHERN ILLINOIS INTO THE OHIO RIVER VALLEY...HOWEVER VERY LITTLE FOCUS FOR ORGANIZED CONVECTION EXISTS FURTHER NORTH ACROSS THE REMAINDER OF THE AREA. AS A RESULT...WILL ONLY CARRY LOW CHANCE POPS THROUGH THE PERIOD. DEEP UPPER LOW OVER CALIFORNIA WILL GRADUALLY EJECT NORTHEASTWARD LATE IN THE WEEKEND. MODELS ARE IN GOOD AGREEMENT WITH THIS PROCESS THROUGH 144 HOURS...THEN SOLUTIONS BEGIN TO DIVERGE AFTER THAT. BOTH THE GFS AND ECMWF SHOW THE LOW TRACKING INTO THE DAKOTAS BY SUNDAY EVENING...WITH CONVECTION DEVELOPING ALONG A TRAILING COLD FRONT ACROSS THE PLAINS. THE ECMWF THEN BECOMES MORE PROGRESSIVE WITH THE WAVE...AS IT OPENS UP AND PUSHES EASTWARD INTO THE NORTHERN GREAT LAKES BY MONDAY. MEANWHILE...THE GFS KEEPS THE LOW CLOSED LONGER AND IS THUS SLOWER WITH ITS EASTWARD TRACK. THIS MAKES A BIG DIFFERENCE WITH TIMING OF ASSOCIATED COLD FRONT...AS GFS LINGERS THIS BOUNDARY AND RAIN CHANCES UNTIL TUESDAY. SINCE OVERALL SYNOPTIC PATTERN HAS BEEN PROGRESSIVE OVER THE PAST WEEK AND THE GEM SUPPORTS THE ECMWF...WILL BE GOING WITH THE FASTER ECMWF/GEM SOLUTION IN THE EXTENDED. AS A RESULT...WILL BRING LIKELY POPS INTO THE FAR WESTERN CWA SUNDAY AFTERNOON...THEN FURTHER EAST ACROSS THE REMAINDER OF THE AREA SUNDAY NIGHT. WILL THEN BEGIN TO SHIFT THE RAIN CHANCES OUT OF THE PICTURE ON MONDAY...WITH DRY WEATHER RETURNING MONDAY NIGHT AND TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1154 PM CDT MON MAY 11 2015 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WRAP- AROUND CLOUDS CONTINUE TO MOVE ACROSS THE NORTHERN THIRD OF THE STATE WITH BROKEN TO OVERCAST CLOUDS OCCURRING AT PIA. THESE CLOUDS SHOULD REACH BMI SO WILL HAVE BROKEN TO OVERCAST CLOUDS AT BOTH SITES BUT HAVE A TEMPO GROUP FOR BMI FOR FIRST SEVERAL HOURS OF TAF FOR SCATTERED CLOUDS. OTHER SITES WILL JUST SEE SCATTERED CLOUDS OVERNIGHT AND THROUGH MOST OF THE DAY. HRRR MODEL SHOWS THE POSSIBILITY OF SOME BROKEN CIGS REACHING CMI IN THE MORNING SO WILL HAVE TEMPO GROUP TO COVER THAT IN THE MORNING. ALL SITES WILL EITHER REMAIN SCATTERED OR SCATTER OUT DURING THE MORNING HOURS AND THEN BECOME CLEAR LATE MORNING TO EVENING HOURS. WEST WINDS WILL CONTINUE AND THEN BECOME NORTHWEST TOMORROW EVENING. GUSTY WINDS ARE EXPECTED AGAIN TOMORROW. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1154 PM CDT MON MAY 11 2015 .UPDATE... ISSUED AT 904 PM CDT MON MAY 11 2015 WRAP-AROUND CLOUDS CONTINUE TO SLOWLY MAKE THEIR WAY INTO THE AREA THIS EVENING WITH THE THICKEST CLOUDS BEING ACROSS THE NORTHERN THIRD OF THE CWA. STILL COULD GET SOME CLOUDS ACROSS THE I-72 CORRIDOR, BUT SHOULD REMAIN PARTLY CLOUDY OVERNIGHT. REMAINDER OF THE FORECAST LOOKS FINE WITH LOWS IN THE MID 40S TO LOWER 50S. WINDS SHOULD STAY UP A TAD AS WELL WITH GUSTS STILL SHOWING UP AT SOME SITES. WILL MAKE SOME ADJUSTMENTS TO CLOUD COVER AND WINDS IN THE GRIDS. WILL SEND AN UPDATE SHORTLY, THOUGH THERE WILL PROBABLY NOT BE MUCH CHANGE IN THE WORDED FORECAST. && .SHORT TERM...(TONIGHT) ISSUED AT 255 PM CDT MON MAY 11 2015 A COLD FRONT DELINEATED BY A THIN LINE OF SHOWERS EXTENDED FROM JUST WEST OF CHICAGO TO JUST EAST OF BLOOMINGTON AND TAYLORVILLE. THIS FRONT WILL PUSH EAST TO THE IL/IN BORDER BY 00Z/7 PM WITH ISOLATED SHOWERS POSSIBLE ALONG AND AHEAD OF IT THE REST OF THE EASTERN IN EASTERN IL. ISOLATED THUNDERSTORMS SHOULD MOSTLY STAY EAST OF CENTRAL IL OVER INDIANA REST OF TODAY WHILE SEVERE STORMS STAY OVER OHIO AND EASTERN PARTS OF IN/KY INTO EARLY EVENING. OTHERWISE DRY CONDITIONS EXPECTED TONIGHT INTO TUE ACROSS CENTRAL AND SOUTHEAST IL ALONG WITH BREEZY AND COOLER CONDITIONS. LOW CLOUDS WERE DECREASING BEHIND THE COLD FRONT WEST OF I-55 AT MID AFTERNOON AND EXPECT THESE CLOUDS TO CONTINUE TO DECREASE OVER EASTERN IL LATE THIS AFTERNOON AND EARLY EVENING. ANOTHER AREA OF LOW CLOUDS OVER IA AND NW MO WAS TRACKING EASTWARD AND WILL SKIRT ACROSS THE IL RIVER VALLEY BY THIS EVENING SO HAVE MORE CLOUDS OVER NORTHERN/NW COUNTIES TONIGHT. THE SOUTHERN/SE EDGE OF THESE CLOUDS IS DIURNALLY ENHANCED SO MAY SEE THIS DISSIPATE AFTER SUNSET. 1003 MB SURFACE LOW PRESSURE OVER CENTRAL MN WILL TRACK EASTWARD ACROSS NORTHERN MI OVERNIGHT AND FAIRLY TIGHT PRESSURE GRADIENT TO REMAIN OVER CENTRAL IL INTO TUE. SW WINDS OF 15 TO 25 MPH AND GUSTS OF 25 TO 30 MPH THIS AFTERNOON TO SHIFT MORE WESTERLY DURING THE NIGHT AND DIMINISH TO 10-17 MPH AFTER SUNSET WITH GUSTS 18-25 MPH THIS EVENING. .LONG TERM...(TUESDAY THROUGH MONDAY) ISSUED AT 255 PM CDT MON MAY 11 2015 A COUPLE COOLER DAYS, ALTHOUGH NOT AS COOL AS ANTICIPATED A FEW DAYS AGO, ARE EXPECTED TUESDAY AND WEDNESDAY. A SPRAWLING SURFACE HIGH WILL BUILD ACROSS THE AREA DURING THE PERIOD, WITH THE UPPER LEVEL FLOW QUICKLY TRANSITIONING FROM WEAK TROFFING TO A BUILDING RIDGE. THIS SCENARIO IS ALSO SUPPORTIVE OF DRY WEATHER CONDITIONS. HOWEVER, CONDITIONS FLIP RATHER QUICKLY BACK TO WARM AND UNSETTLED AFTER THE MIDDLE OF THE WEEK. A SYSTEM CURRENTLY DIVING DOWN THE WEST COAST WILL CARVE OUT A NEW WESTERN U.S. TROF, WHICH WILL HELP DEVELOP A DOWNSTREAM EASTERN U.S. RIDGE. DISTURBANCES EJECTING OUT OF THIS TROF WILL CAUSE PERIODIC SHOWERS/STORMS ACROSS CENTRAL AND SOUTHEAST ILLINOIS FOR THE END OF THE WEEK AND THE WEEKEND, MUCH AS WAS SEEN THIS PAST WEEKEND. TEMPERATURES SHOULD ALSO TREND WELL ABOVE NORMAL, WITH DAYTIME HIGHS HEADING BACK TOWARD THE 80S BY THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1154 PM CDT MON MAY 11 2015 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WRAP- AROUND CLOUDS CONTINUE TO MOVE ACROSS THE NORTHERN THIRD OF THE STATE WITH BROKEN TO OVERCAST CLOUDS OCCURRING AT PIA. THESE CLOUDS SHOULD REACH BMI SO WILL HAVE BROKEN TO OVERCAST CLOUDS AT BOTH SITES BUT HAVE A TEMPO GROUP FOR BMI FOR FIRST SEVERAL HOURS OF TAF FOR SCATTERED CLOUDS. OTHER SITES WILL JUST SEE SCATTERED CLOUDS OVERNIGHT AND THROUGH MOST OF THE DAY. HRRR MODEL SHOWS THE POSSIBILITY OF SOME BROKEN CIGS REACHING CMI IN THE MORNING SO WILL HAVE TEMPO GROUP TO COVER THAT IN THE MORNING. ALL SITES WILL EITHER REMAIN SCATTERED OR SCATTER OUT DURING THE MORNING HOURS AND THEN BECOME CLEAR LATE MORNING TO EVENING HOURS. WEST WINDS WILL CONTINUE AND THEN BECOME NORTHWEST TOMORROW EVENING. GUSTY WINDS ARE EXPECTED AGAIN TOMORROW. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AUTEN SHORT TERM...07 LONG TERM...BAK AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
614 PM EDT TUE MAY 12 2015 .SYNOPSIS... LOW PRESSURE WILL CONTINUE ACROSS QUEBEC TONIGHT BRINGING A COLD FRONT INTO THE AREA. THE COLD FRONT WILL PUSH THROUGH THE REGION WEDNESDAY MORNING AND OFF THE COAST. HIGH PRESSURE WILL BUILD TOWARD THE REGION LATER WEDNESDAY NIGHT INTO THURSDAY. && .NEAR TERM /THROUGH WEDNESDAY/... 614 PM UPDATE...A LINE OF SHOWERS MOVING OUT OF CENTRAL MAINE WILL QUICKLY MOVE TO THE NEW BRUNSWICK BORDER OVER THE NEXT 1 TO 2 HOURS. CALLS TO WEATHER SPOTTERS INDICATE SOME HEAVY DOWNPOURS...BUT LITTLE WIND. THUS FAR ONLY SOME IN CLOUD LIGHTNING DETECTED. ONCE THIS LINE MOVES OUT OF THE AREA ATTENTION TURNS TO SHOWERS AND THUNDERSTORMS IN QUEBEC THAT WILL DRIFT INTO FAR NORTHERN MAINE OVER THE NEXT FEW HOURS. MAIN ADJUSTMENT WAS TO THE POPS OVER THE NEXT COUPLE OF HOURS TO ACCOUNT FOR THE LINE OF SHOWERS MOVING OUT OF CENTRAL MAINE. PREVIOUS DISCUSSION... ISOLATED THUNDERSTORMS POSSIBLE W/SOME DECENT WIND GUSTS. LOW CLOUDS SLOWLY ERODING ACROSS THE EASTERN AREAS THIS AFTERNOON KEEPING THE LLVLS STABLE WHILE WESTERN AND SW AREAS HAVE BROKEN OUT W/SUNSHINE AND HENCE TEMPS WARMING. THIS HAS ALLOWED FOR THINGS TO DESTABILIZE MORE. 18Z SURFACE ANALYSIS HAD THE WARM FRONT/PRE-FRONTAL BOUNDARY SLOWLY LIFT INTO WESTERN MAINE W/THE COLD FRONT STILL BACK WESTERN QUEBEC. STEADY RAIN HAS ENDED OR MOVED E W/A MORE SHOWERY NATURE OF THE PRECIP SETTING UP. LATEST NAM AND RAP SOUNDINGS SUPPORT DECENT SB/MU CAPE OF 700+ JOULES W/LIS DOWN TO -2 IN THESE AREAS. GOOD SHEAR IN THE 0-6KM LAYER AROUND 35 KTS. SPC MESO ANALYSIS SHOWED DECENT MID LEVEL LAPSE RATES OF 6.5 C/KM HELPING W/INSTABILITY. KEPT ENHANCED WORDING FOR FOR NOW FOR GUSTY WINDS AND HEAVY RAINFALL POTENTIAL. THINGS WILL WIND DOWN ACROSS THE W AND SW THIS EVENING AND THEN SHIFT ACROSS THE NORTHERN AREAS AS THE COLD FRONT APCHS W/LOW PRES PASSING ACROSS SOUTHERN QUEBEC. 12Z UA SHOWED DECENT MID LEVEL COOLING AND STRONG JET FROM 700-500MBS OF AROUND 65 KTS. THOSE STRONGER WINDS COULD GET MIXED DOWN SOME TO THE SFC W/ANY ELEVATED CONVECTION. LEANED W/ENHANCED WORDING FOR THE GUSTY WINDS IN ANY STORMS THROUGH MIDNIGHT. HEAVY RAINFALL POTENTIAL IS POSSIBLE AS WELL W/THE STORMS MOVING PARALLEL TO THE UPPER FLOW. CONVECTIVE POTENTIAL WINDS DOWN AFTER MIDNIGHT W/JUST SHOWERS AND THE BULK OF THE ACTION ACROSS THE NORTHERN TIER. COOLING TO TAKE AFFECT AS NW WIND TAKE OVER THROUGH THE COLUMN. WE ARE TALKING UPPER 30S BACK ACROSS THE WNW BY EARLY WEDNESDAY MORNING W/40S ELSEWHERE. THIS COLD AIR CAN BE SEEN ALREADY SHOWING UP IN NW QUEBEC. WEDNESDAY WILL BE MUCH COOLER W/THE UPPER TROF ACROSS THE REGION W/UPPER 50S NORTH AND WEST WHILE CENTRAL AND DOWNEAST WILL SEE AROUND 60F OR SO DUE TO SOME DOWNSLOPING. IT WILL BE BREEZY W/NW WINDS. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... STRONG HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WEDNESDAY NIGHT AND CREST OVER THE REGION EARLY FRIDAY KEEPING THE STATE RELATIVELY DRY. WILL BLEND THE GFS AND ECMWF FOR POPS... QPF AND SKY CONDITIONS. FOR WINDS HAVE USED THE MOSG25. THE SUPER BLEND WAS USED TO POPULATE THE TEMPERATURE AND DEW POINT GRIDS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... STRONG HIGH PRESSURE WILL MOVE OFF THE EAST COAST LATE FRIDAY. WEAK LOW PRESSURE WILL PASS TO THE SOUTH OF THE REGION SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH MONDAY. A COLD FRONT WILL APPROACH FROM THE WEST MONDAY NIGHT AND CROSS THE REGION TUESDAY. WILL USE THE SUPER BLEND TO POPULATE ALL GRIDS. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... NEAR TERM: MOSTLY VFR EARLYTHIS EVENING AT THE NORTHERN TERMINALS WITH CONDITIONS TO DROP BACK TO MVFR AND IFR W/THE APCHG COLD FRONT TONIGHT. IMPROVEMENT TO MVFR BY MID MORNING AND VFR BY LATE IN THE DAY. KBGR AND KBHB WILL SEE VFR THROUGH TUESDAY. THERE IS A RISK OF AN ISOLATED TSTM THROUGH THIS EVENING W/GUSTY WINDS. SHORT TERM: EXPECT VFR CONDITIONS WEDNESDAY NIGHT THROUGH SUNDAY. && .MARINE... NEAR TERM: SCA FOR HAZARDOUS SEAS IS IN EFFECT INCLUDING THE INTRA-COASTAL ZONE. A SWELL BEING GENERATED FROM LEFTOVER TD ANA IS FORECAST LIFT ACROSS THE WATERS LATER THIS EVENING INTO WEDNESDAY. DECIDED ON HEIGHTS UP TO A RANGE OF 6-7 FT W/THE HIGHEST WAVES OVER THE OUTER WATERS. THE INTRA-COASTAL ZONE WILL MOST LIKELY SEE WAVES OF AROUND 5FT W/A 8-9 SECOND PERIOD. FOG WILL BE A NUISANCE FOR NAVIGATION THROUGH TONIGHT. FOR THE WINDS, DECIDED ATTM TO KEEP WIND GUSTS IN THE LOWER 2OS ON WEDNESDAY W/THE NW FLOW. THE OUTER WATERS COULD SEE GUSTS HIT 25 KT FOR A BRIEF PERIOD. SHORT TERM: HAVE BLENDED THE NAM12 AND GFS40 FOR SUSTAINED WINDS WEDNESDAY NIGHT THROUGH FRIDAY THEN TRANSITION TO THE SUPER BLEND WINDS. FOR WAVES: PRIMARY WAVE SYSTEM WILL BE LONG PERIOD SWELL FROM REMNANTS OF TROPICAL DEPRESSION ANA. EXPECT 5 FEET/9-10 SECONDS WAVE HEIGHTS WEDNESDAY NIGHT SUBSIDING DURING THE DAY THURSDAY. WILL CARRY AN SCA EARLY WEDNESDAY EVENING BUT EXPECT SEAS TO SUBSIDE BELOW SCA LATER AT NIGHT AS THE LONG PERIOD WAVE SYSTEM SUBSIDES. WILL USE THE NEAR SHORE WAVE MODEL THROUGH FRIDAY THEN TRANSITION TO THE WAVE WATCH III. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM MIDNIGHT TONIGHT TO MIDNIGHT EDT WEDNESDAY NIGHT FOR ANZ050>052. && $$ NEAR TERM...CB/HEWITT SHORT TERM...MIGNONE LONG TERM...MIGNONE AVIATION...CB/HEWITT/MIGNONE MARINE...CB/HEWITT/MIGNONE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
354 PM EDT TUE MAY 12 2015 .SYNOPSIS... LOW PRESSURE WILL CONTINUE ACROSS QUEBEC TONIGHT BRINGING A COLD FRONT INTO THE AREA. THE COLD FRONT WILL PUSH THROUGH THE REGION WEDNESDAY MORNING AND OFF THE COAST. HIGH PRESSURE WILL BUILD TOWARD THE REGION LATER WEDNESDAY NIGHT INTO THURSDAY. && .NEAR TERM /THROUGH WEDNESDAY/... ISOLATED THUNDERSTORMS POSSIBLE W/SOME DECENT WIND GUSTS. LOW CLOUDS SLOWLY ERODING ACROSS THE EASTERN AREAS THIS AFTERNOON KEEPING THE LLVLS STABLE WHILE WESTERN AND SW AREAS HAVE BROKEN OUT W/SUNSHINE AND HENCE TEMPS WARMING. THIS HAS ALLOWED FOR THINGS TO DESTABILIZE MORE. 18Z SURFACE ANALYSIS HAD THE WARM FRONT/PRE-FRONTAL BOUNDARY SLOWLY LIFT INTO WESTERN MAINE W/THE COLD FRONT STILL BACK WESTERN QUEBEC. STEADY RAIN HAS ENDED OR MOVED E W/A MORE SHOWERY NATURE OF THE PRECIP SETTING UP. LATEST NAM AND RAP SOUNDINGS SUPPORT DECENT SB/MU CAPE OF 700+ JOULES W/LIS DOWN TO -2 IN THESE AREAS. GOOD SHEAR IN THE 0-6KM LAYER AROUND 35 KTS. SPC MESO ANALYSIS SHOWED DECENT MID LEVEL LAPSE RATES OF 6.5 C/KM HELPING W/INSTABILITY. KEPT ENHANCED WORDING FOR FOR NOW FOR GUSTY WINDS AND HEAVY RAINFALL POTENTIAL. THINGS WILL WIND DOWN ACROSS THE W AND SW THIS EVENING AND THEN SHIFT ACROSS THE NORTHERN AREAS AS THE COLD FRONT APCHS W/LOW PRES PASSING ACROSS SOUTHERN QUEBEC. 12Z UA SHOWED DECENT MID LEVEL COOLING AND STRONG JET FROM 700-500MBS OF AROUND 65 KTS. THOSE STRONGER WINDS COULD GET MIXED DOWN SOME TO THE SFC W/ANY ELEVATED CONVECTION. LEANED W/ENHANCED WORDING FOR THE GUSTY WINDS IN ANY STORMS THROUGH MIDNIGHT. HEAVY RAINFALL POTENTIAL IS POSSIBLE AS WELL W/THE STORMS MOVING PARALLEL TO THE UPPER FLOW. CONVECTIVE POTENTIAL WINDS DOWN AFTER MIDNIGHT W/JUST SHOWERS AND THE BULK OF THE ACTION ACROSS THE NORTHERN TIER. COOLING TO TAKE AFFECT AS NW WIND TAKE OVER THROUGH THE COLUMN. WE ARE TALKING UPPER 30S BACK ACROSS THE WNW BY EARLY WEDNESDAY MORNING W/40S ELSEWHERE. THIS COLD AIR CAN BE SEEN ALREADY SHOWING UP IN NW QUEBEC. WEDNESDAY WILL BE MUCH COOLER W/THE UPPER TROF ACROSS THE REGION W/UPPER 50S NORTH AND WEST WHILE CENTRAL AND DOWNEAST WILL SEE AROUND 60F OR SO DUE TO SOME DOWNSLOPING. IT WILL BE BREEZY W/NW WINDS. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... STRONG HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WEDNESDAY NIGHT AND CREST OVER THE REGION EARLY FRIDAY KEEPING THE STATE RELATIVELY DRY. WILL BLEND THE GFS AND ECMWF FOR POPS... QPF AND SKY CONDITIONS. FOR WINDS HAVE USED THE MOSG25. THE SUPER BLEND WAS USED TO POPULATE THE TEMPERATURE AND DEW POINT GRIDS. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE WILL MOVE OFF THE EAST COAST LATE FRIDAY. WEAK LOW PRESSURE WILL PASS TO THE SOUTH OF THE REGION SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH MONDAY. A COLD FRONT WILL APPROACH FROM THE WEST MONDAY NIGHT AND CROSS THE REGION TUESDAY. WILL USE THE SUPER BLEND TO POPULATE ALL GRIDS. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... NEAR TERM: IFR NORTHERN TERMINALS TO GO VFR THIS EVENING AND THEN DROP BACK TO MVFR AND IFR W/THE APCHG COLD FRONT TONIGHT. IMPROVEMENT TO MVFR BY MID MORNING AND VFR BY LATE IN THE DAY. KBGR AND KBHB WILL SEE VFR THROUGH TUESDAY. THERE IS A RISK OF AN ISOLATED TSTM THROUGH THIS EVENING W/GUSTY WINDS. SHORT TERM: EXPECT VFR CONDITIONS WEDNESDAY NIGHT THROUGH SUNDAY. && .MARINE... NEAR TERM: SCA FOR HAZARDOUS SEAS IS IN EFFECT INCLUDING THE INTRA-COASTAL ZONE. A SWELL BEING GENERATED FROM LEFTOVER TD ANA IS FORECAST LIFT ACROSS THE WATERS LATER THIS EVENING INTO WEDNESDAY. DECIDED ON HEIGHTS UP TO A RANGE OF 6-7 FT W/THE HIGHEST WAVES OVER THE OUTER WATERS. THE INTRA-COASTAL ZONE WILL MOST LIKELY SEE WAVES OF AROUND 5FT W/A 8-9 SECOND PERIOD. FOG WILL BE A NUISANCE FOR NAVIGATION THROUGH TONIGHT. FOR THE WINDS, DECIDED ATTM TO KEEP WIND GUSTS IN THE LOWER 2OS ON WEDNESDAY W/THE NW FLOW. THE OUTER WATERS COULD SEE GUSTS HIT 25 KT FOR A BRIEF PERIOD. SHORT TERM: HAVE BLENDED THE NAM12 AND GFS40 FOR SUSTAINED WINDS WEDNESDAY NIGHT THROUGH FRIDAY THEN TRANSITION TO THE SUPER BLEND WINDS. FOR WAVES: PRIMARY WAVE SYSTEM WILL BE LONG PERIOD SWELL FROM REMNANTS OF TROPICAL DEPRESSION ANA. EXPECT 5 FEET/9-10 SECONDS WAVE HEIGHTS WEDNESDAY NIGHT SUBSIDING DURING THE DAY THURSDAY. WILL CARRY AN SCA EARLY WEDNESDAY EVENING BUT EXPECT SEAS TO SUBSIDE BELOW SCA LATER AT NIGHT AS THE LONG PERIOD WAVE SYSTEM SUBSIDES. WILL USE THE NEAR SHORE WAVE MODEL THROUGH FRIDAY THEN TRANSITION TO THE WAVE WATCH III. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM MIDNIGHT TONIGHT TO MIDNIGHT EDT WEDNESDAY NIGHT FOR ANZ050>052. && $$ NEAR TERM...HEWITT SHORT TERM...MIGNONE LONG TERM...MIGNONE AVIATION...HEWITT/MIGNONE MARINE...HEWITT/MIGNONE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
400 AM EDT TUE MAY 12 2015 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA LATE TODAY. HIGH PRESSURE RETURNS WEDNESDAY AND THURSDAY...THEN PUSHES OFFSHORE ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... THE REMNANTS OF ANA HAVE PUSHED WELL OFF THE MID-ATLANTIC COAST THIS MORNING. THE NEXT FEATURE TO IMPACT THE LOCAL AREA IS A COLD FRONT CURRENTLY MAKING ITS WAY THROUGH THE OH VALLEY...AND STRETCHING SOUTHWARD TO THE LOWER MS VALLEY. WARM/HUMID SW FLOW IN PLACE THIS MORNING IS MAKING IT FEEL MORE LIKE MID-SUMMER WITH TEMPS GENERALLY IN THE MID 60S TO MID 70S AT THIS HOUR. THE CURRENT RADAR SCANS SHOWS THAT THE CONVECTION FROM LAST EVENING HAS WANED. HOWEVER...A NEW ROUND OF SHWR ACTIVITY STRETCHING FROM NEAR LYNCHBURG TO MARTINSVILLE IS POISED TO MAKE A RUN AT OUR EASTERN PIEDMONT COUNTIES BY AROUND DAYBREAK. WILL CARRY SLIGHT CHC POPS WESTERN AREAS THRU AROUND 9 AM TO ACCOUNT FOR THIS POSSIBILITY. LATEST HRRR APPEARS A BIT ROBUST WITH PCPN MAKING IT ALL THE WAY TO RICHMOND...BUT DOES SUPPORT THE AFOREMENTIONED SLIGHT CHC POPS. THE COLD FRONT CONTINUES TO MOVE EAST THROUGH THE DAY...REACHING EASTERN PORTIONS OF THE FA AROUND 00Z. AHEAD OF THE FRONT...MODELS ARE IN GOOD AGREEMENT SHOWING A PRE-FRONTAL TROUGH SHARPENING ACROSS THE PIEDMONT BY 18Z WITH DEEP LAYERED WSW FLOW BRINGING DRIER AIR (AND SIGNIFICANT LOWERING OF DEW POINTS) INTO THE REGION. THE BEST MOISTURE AHEAD OF THE APPROACHING COLD FRONT IS SHOWN TO QUICKLY SHIFT EAST INTO EASTERN AREAS THIS AFTN/EVE... ESPECIALLY SE VA AND NE NC. MODEL SOUNDINGS SHOW A STRONG CAP DEVELOPING BETWEEN 6-8KFT DURING THE AFTN HOURS ALONG AND NW OF A LINE FROM AVC-PTB-WAL...WHICH WILL INHIBIT CONVECTION. SLOWER DEEP LAYERED DRYING AND A WEAKER CAP IN SE VA/NE NC DURING THE AFTN/EARLY EVE MAY RESULT IN POSSIBLE ISOLD/SCT CONVECTION AT TIME OF PEAK HEATING. POPS WERE ADJUSTED ACCORDINGLY TO REFLECT A 30% POP FROM ABOUT THE TRI-CITIES ON SOUTHEAST THIS AFTN/EVE. SPC HAS SE VA/NE NC ONLY IN A MARGINAL RISK OF SVR WX LATER TODAY...AS THERE MAY BE JUST ENOUGH INSTABILITY/MOISTURE IN PLACE (ML CAPE 1000-1500 J/KG) COUPLED WITH MODEST SHEAR 20-30 KT TO PRODUCE AN ISOLD DAMAGING WIND GUST THREAT. OTW...TODAY WILL BE SUMMER-LIKE WITH HIGH TEMPS IN THE MID-UPR 80S ALONG THE IMMEDIATE COAST...UPR 80S-LOW 90S ELSEWHERE. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... SUBSTANTIAL DRYING TONIGHT THROUGH WED AS FLOW ALOFT BECOMES NW AND SFC HIGH PRESSURE BUILDS TWD THE FA FROM THE GREAT LAKES. LOW TEMPS TONIGHT FROM THE MID-UPR 50S...EXCEPT LOW 60S SE. SUNNY AND LESS HUMID WED AS SFC HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION FROM THE NW. HIGH TEMPS RANGING FROM THE MID 60S-LOW 70S ALONG THE COAST...MID-UPR 70S INLAND. DRY/PLEASANT WX WED NIGHT/THU W/ LGT/VRB WINDS AND CLEAR-PTCLDY SKY. LOW TEMPS WED NIGHT FROM THE MID-UPR 40S INLAND TO THE MID 50S AT THE COAST. HIGH TEMPS THU 65 TO 70F AT THE BEACHES TO THE LOW-MID 70S INLAND. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE RESIDES OVER THE AREA FOR ONE MORE NIGHT...KEEPING LOW TEMPERATURES IN THE LOWER 50S INLAND AND MID-UPPER 50S AT THE IMMEDIATE COAST. HIGH PRESSURE THEN SLIDES OFF THE COAST DURING THE DAY ON FRIDAY...ALLOWING WARM AIR ADVECTION PROCESSES TO COMMENCE IN RETURN SWLY FLOW. GULF MOISTURE WILL GRADUALLY BE PULLED INTO THE REGION AROUND THE BACK SIDE OF A LARGE-SCALE HIGH PRESSURE OVER THE SOUTHEAST COAST...THUS INTRODUCING PRECIPITATION BACK INTO THE FORECAST BEGINNING FRIDAY AFTERNOON. UNSETTLE CONDITIONS THEN PREVAIL THROUGH THE UPCOMING WEEKEND AND INTO EARLY NEXT WEEK WITH NO SIGNIFICANT UPSTREAM FEATURES TO PUSH THE HIGH SOUTH OR EAST. EXPECT PERIODS OF OFF AND ON RAIN SHOWERS/AFTN THUNDERSTORMS (30-40 PERCENT) DURING THIS TIMEFRAME. HIGHS SLOWLY REBOUND TO SLIGHTLY ABOVE SEASONAL NORMALS THROUGH THE WEEKEND AS THE SFC HIGH MOVES OFFSHORE. EXPECT HIGHS 75-85 (5-7 DEGREES COOLER AT THE IMMEDIATE COAST) AND LOWS IN THE LOW-MID 60S. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... THE REMNANT LOW FROM ANA IS NOW IN VICINITY OF THE CENTRAL NJ COAST AS OF 06Z...AND IS IN THE PROCESS OF BECOMING ABSORBED BY LOW PRESSURE OVER THE GREAT LAKES. A COLD FRONT ASSOCIATED WITH THE GREAT LAKES LOW IS BACK OVER THE OHIO VALLEY. THE LOCAL AREA IS NOW WITHIN A REGION OF SW FLOW AHEAD OF THE COLD FRONT. BKN CIGS AOA 6KFT COMBINED WITH A 6-10KT SW WIND SHOULD INHIBIT FOG DEVELOPMENT OVERNIGHT. THE BEST CHC FOR MVFR VSBY IS AT SBY WHERE THE DEWPOINT DEPRESSION IS 2F...MEANWHILE OTHER LOCATIONS ARE 8-10F. ISOLATED -SHRA/TSRA WILL LINGER OVERNIGHT...BUT THE PROBABILITY OF A DIRECTLY AFFECTING A TAF SITE IS VERY LOW. OTHERWISE...EXPECT BREEZY CONDITIONS TO DEVELOP LATER THIS MORNING AHEAD OF THE COLD FRONT WITH A SW WIND AVERAGING 12-15KT...WITH GUSTS OF 20-25KT THROUGH THE AFTERNOON. A FEW -SHRA/TSRA ARE POSSIBLE THIS AFTERNOON MAINLY OVER SE VA/NE NC. THE COLD FRONT SWEEPS THROUGH THE AREA THIS EVENING...WITH HIGH PRESSURE PREVAILING MIDWEEK. HIGH PRESSURE MOVES OFFSHORE FRIDAY AND SATURDAY. && .MARINE... THE REMNANT LOW OF ANA ABSORBS INTO LOW PRESSURE TRACKING ACROSS THE SAINT LAWRENCE VALLEY TODAY. THIS WILL DRAG A COLD FRONT TOWARD THE REGION TODAY...WITH THE BOUNDARY CROSSING THE COAST THIS EVENING. EXPECT A SW WIND TO AVERAGE ~15KT OVER THE BAY EARLY TODAY WITH 15- 20KT OVER THE OCEAN...BEFORE RELAXING TO 10-15KT THIS AFTERNOON. A SHORT DURATION PERIOD OF ~20KT IS POSSIBLE ACROSS THE LOWER BAY/LOWER JAMES AROUND 10-12Z BUT SHOULD NOT BE LONG ENOUGH TO WARRANT AN SCA. ADDITIONALLY...A FEW TSTMS ARE POSSIBLE WITH THE FRONTAL PASSAGE THIS AFTERNOON AND EVENING. MODEST CAA ARRIVES LATER TONIGHT INTO EARLY WEDNESDAY...ESPECIALLY ACROSS THE NRN HALF OF THE AREA IN THE WAKE OF THE FRONT. AN SCA HAS BEEN ISSUED FOR THE BAY FOR LATE TONIGHT INTO WEDNESDAY MORNING. THE SCA N OF PARRAMORE ISLAND HAS BEEN EXTENDED THROUGH TODAY AS SEAS COULD LINGER ~5FT (ESPECIALLY OUT NEAR 20NM)...AND CONTINUING TONIGHT INTO WEDNESDAY MORNING FOR THE CAA SURGE. A SECONDARY NORTHERLY SURGE WEDNESDAY NIGHT HAS THE POTENTIAL TO PRODUCE MARGINAL SCA CONDITIONS...BEFORE HIGH PRESSURE SETTLES INTO THE REGION THURSDAY AND THURSDAY NIGHT. HIGH PRESSURE MOVES OFFSHORE FRIDAY AND SATURDAY ALLOWING THE WIND TO RETURN TO SSW. SEAS SHOULD AVERAGE 2-4FT LATER WEDNESDAY THROUGH SATURDAY...WITH WAVES IN THE BAY AVERAGING 1-3FT. && .CLIMATE... RATHER HOT TUE...WITH A GOOD CHANCE AT SEEING OUR 1ST 90- DEGREE DAY OF THE YEAR: MEAN DATE OF 1ST 90-DEGREE DAY (1981-2010 CLIMATOLOGY): RICHMOND....MAY 13TH NORFOLK.....MAY 17TH SALISBURY...MAY 27TH ELIZ CITY...MAY 25TH RECORD HIGHS POSSIBLE TUE...RECORDS ARE LISTED BELOW FOR MAY 12TH: RICHMOND....92 (1956) NORFOLK.....92 (1881) SALISBURY...93 (1914) ELIZ CITY...90 (2001) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ650- 652-654. && $$ SYNOPSIS...JDM NEAR TERM...JDM SHORT TERM...ALB/JDM LONG TERM...BMD AVIATION...AJZ MARINE...AJZ CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
139 AM EDT TUE MAY 12 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 421 PM EDT MON MAY 11 2015 WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW THE MID LEVEL LOW THAT WAS OVER WRN NEBRASKA/SD 24HRS AGO NOW CENTERED IN WCNTRL MN. AHEAD OF FEATURE...WARM CONVEYOR BELT MOISTURE RIBBON EXTENDS FROM THE LWR MISSISSIPPI VALLEY TO THE WRN GREAT LAKES. RESULT HAS BEEN NMRS SHRA SPREADING ACROSS THE FCST AREA TODAY. A FEW TSTMS WERE NOTED THIS MORNING OVER THE W HALF OF UPPER MI. AT THE SFC...LOW PRES LOCATED IN CNTRL MN IS BECOMING LESS WELL-DEFINED WITH TENDENCY FOR LOW PRES REDEVELOPMENT AT THE TRIPLE POINT FARTHER E. OCCLUDED FRONT IS APPROACHING THE MI/WI BORDER AS OF 20Z. AS THE WARM CONVEYOR MOISTURE RIBBON TRANSLATES E...WIDESPREAD SHRA NOW OVER THE E HALF OF THE FCST AREA WILL ALSO SHIFT E AND OUT OF THE AREA IN THE NEXT FEW HRS. FOG AND SOME -DZ WILL PERSIST IN THE UPSLOPE FLOW OFF LAKE SUPERIOR INTO THE KEWEENAW AND WRN PORTIONS OF NCNTRL UPPER MI...AND A FEW SHRA MAY DEVELOP NEAR THE OCCLUDED FRONT WHICH SHOULD LIFT INTO OR THRU MUCH OF CNTRL AND ERN UPPER MI THIS EVENING. OTHERWISE...AS MID LEVEL LOW OPENS UP AND UPPER TROF MOVES E INTO THE WRN GREAT LAKES TONIGHT...DEEPER MOISTURE WILL WRAP BACK INTO THE AREA FROM THE N AND W. AIDED BY DEEP CYCLONIC FLOW...SHRA WILL SPREAD BACK INTO THE FCST AREA...ESPECIALLY ACROSS THE W. AS CAA INCREASES OVERNIGHT...FCST SOUNDINGS/WETBULB ZERO HEIGHTS SUGGEST POTENTIAL FOR SNOW TO MIX WITH THE RAIN OVER THE HIGH TERRAIN OF THE W LATE TONIGHT. AS TROF CONTINUES TO SHIFT E TUE...DEEP LAYER QVECTOR DIVERGENCE OVERSPREADS THE AREA WITH HEIGHTS BEGINNING TO RISE...MORE SUBSTANTIALLY IN THE AFTN. THIS WILL TEND TO DIMINISH THE WRAP AROUND PCPN WITH TIME...BUT THIS WILL BE COUNTERACTED BY SHARP CYCLONIC FLOW AND CONSIDERABLE LOW TO MID LEVEL MOISTURE THAT LINGERS THRU THE DAY. THIS WILL RESULT IN PCPN BEING MOST PERSISTENT IN THE AREAS THAT SEE UPSLOPING UNDER NW TO N WINDS. DOWNSLOPE AREAS WILL SEE PCPN DIMINISH OR END. CONTINUED CAA WILL DROP 850MB TEMPS TO -3 TO AS LOW AS -6C...AND THIS WILL RESULT IN RAIN MIXING WITH SNOW...MAINLY OVER THE HIGHER TERRAIN OF THE W AND CNTRL. PCPN WILL LIKELY CHANGE TO ALL SNOW AT LEAST FOR A TIME OVER THE HIGH TERRAIN OF THE W HALF AS LOWEST 850MB TEMPS ARE FCST THERE. THAT AREA WILL ALSO HAVE THE BEST CHANCE FOR A LITTLE SNOW ACCUMULATION ON GRASSY SFCS. IT WILL BE AN UNSEASONABLY COLD DAY WITH TEMPS AROUND 20 DEGREES BLO NORMAL ACROSS THE W AND N WHERE TEMPS WILL STRUGGLE TO GET MUCH ABOVE 40F. ACROSS THE SCNTRL...TEMPS MAY SNEAK INTO THE LWR 50S. BLUSTERY WINDS WILL ADD TO THE CHILL. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 255 PM EDT MON MAY 11 2015 WILL STILL HAVE SOME LINGERING MAINLY SNOW SHOWERS /WITH A FEW RAIN SHOWERS OR AREAS OF DRIZZLE MIXED IN/ TUESDAY NIGHT OVER THE N HALF OF UPPER MI. THE BEST CHANCE OF PRECIP WILL BE N CENTRAL AS FAVORABLE N-NNW WINDS RESIDE THERE FROM THE SFC-850MB. TEMPERATURES WILL BE COOLING INTO THE LOW 30S OVERNIGHT...WITH LOCATIONS OVER THE INTERIOR W HALF FALLING INTO THE MID 20S AS WINDS BECOME NEARLY CALM AND DRIER AIR WORKS IN AND 850MB TEMPS BEGIN TO WARM SLIGHTLY FROM - 4 TO -6C...TO AROUND -3C. HIGH PRESSURE WILL BE STRETCHING FROM HUDSON BAY THROUGH MANITOBA AND MN...DOWN THROUGH THE MS VALLEY AT 00Z WEDNESDAY. LOOK FOR THE AREA OF HIGH PRESSURE TO BUILD ACROSS THE UPPER GREAT LAKES THROUGH WEDNESDAY...WITH DRY WEATHER FIGURED INTO AT LEAST WEDNESDAY EVENING. WAA WILL TAKE HOLD AT THE SFC ON MAINLY S WINDS OVER THE W HALF OF THE CWA...WITH AFTERNOON HIGHS IN THE 50S FOR MOST LOCATIONS /EXCLUDING THE COOLER N CENTRAL AND E LAKE SUPERIOR SHORELINE/ AS 850MB TEMPS REBOUND TO AROUND 4C W TO 1C E. PRECIP COULD SLIDE IN AS EARLY AS LATE WEDNESDAY AFTERNOON SW /GFS SOLUTION/. THIS WOULD BE ALONG THE SW AS AN INITIAL FRONTAL BOUNDARY SHIFTS TO OUR N. THE MAIN CONCERN IS THAT THE LOWER LEVELS WILL BE TOO DRY WITH THE SFC RIDGE STILL OVER MUCH OF THE AREA WITH THIS BOUNDARY/SHORTWAVE ROUNDING THE 500MB RIDGE. WILL CONTINUE TO GO WITH A MINIMAL PRECIP SOLUTION FOR THIS PERIOD. THE SFC HIGH WILL SHIFT ACROSS THE ENTIRE GREAT LAKES REGION WEDNESDAY NIGHT...WITH SLOWLY INCREASING S FLOW OVER UPPER MI PUSHING IN INCREASED MOISTURE AS 850MB TEMPS RUMP TO AROUND 8C OVER THE SW. THE APEX OF THE 500MB RIDGE WILL BE ACROSS THE AREA THURSDAY AFTERNOON...WITH FCST MODELS INDICATING A NEARING EMBEDDED 500MB TROUGH IN THE SW FLOW OVER THE N PLAINS AND W MN. THE GFS HAS A DEEPER/WRAPPED UP SFC LOW OVER THE CENTRAL PLAINS OFF THE GFS IS NOT QUITE A S STRONG AS THE ECMWF...ESPECIALLY THE PREVIOUS 11/06Z RUN. THIS LEADS TO ONLY MODERATE CONFIDENCE IN THE FCST BEYOND THURSDAY. THE DIFFERENCE SHOWS UP WELL IN THE MODEL QPF...WITH THE 11/06Z GFS SHOWING 24HR PRECIP OF 0.75-1.45IN BY 00Z SATURDAY. THE 11/00Z ECMWF ON THE OTHER HAND RANGES FROM LESS THAN 0.10IN ACROSS THE KEWEENAW PENINSULA...TO 0.5IN OVER FAR S MENOMINEE CO. THIS WILL BE AS THE SFC LOW OFF THE GFS TRACKS FROM THE CENTRAL PLAINS TO N LAKE MI BY 00Z SATURDAY. THE CANADIAN THE ECMWF KEEP A RIDGE ACROSS LAKE SUPERIOR AND MUCH OF UPPER MI DURING THE SAME TIME PERIOD. ON A POSITIVE NOTE...THE 11/12Z GFS CAME IN AT LEAST A LITTLE LESS INTENSE WITH THE SFC LOW...AND DROPS ABOUT 1/2 AS MUCH PRECIP. AN ADDITIONAL LOW DEVELOPING OFF THE N ROCKIES TOWARDS THE END OF THE WORK WEEK WILL LIKELY BE SET UP ACROSS MT AND WY SATURDAY MORNING...AND MOVE ACROSS THE DAKOTAS SATURDAY NIGHT...AND THE UPPER GREAT LAKES ON MONDAY. THE 12Z RUNS HAVE BECOME MUCH MORE IN LINE WITH THE SFC LOW TRACKING OVER E MN/FAR W LAKE SUPERIOR BY 06Z MONDAY. THE RESULT IS AT LEAST MODERATE CONFIDENCE IN RAIN. WILL GO WITH LIKELY PRECIP FOR SUNDAY NIGHT ACROSS MOST OF THE CWA. SO FOR THE UPCOMING WEEKEND IT LOOKS TO BE MAINLY DRY SATURDAY...WITH WET WEATHER APPROACHING SUNDAY AND POSSIBLY LINGERING INTO MONDAY AS THE SFC LOW SLOWLY EDGES E OF THE CWA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 138 AM EDT TUE MAY 12 2015 A LOW PRES SYSTEM WILL MOVE E ACROSS THE UPPER GREAT LAKES TONIGHT AND THEN E TO QUEBEC TUE. ABUNDANT LOW-LEVEL MOISTURE WILL GENERALLY SUPPORT IFR TO LIFR CONDITIONS OVERNIGHT TONIGHT AND -SHRA AT KIWD/KCMX/KSAW TONIGHT WITH THE LOWEST CONDITIONS OCCURRING AT TERMINALS EXPERIENCING UPSLOPE WINDS. COLDER AIR WRAPPING INTO THE AREA BEHIND THE LOW SHOULD BE COLD ENOUGH TO RESULT IN -SHRA MIXING WITH OR CHANGING OVER TO -SHSN LATE TONIGHT/TUE MORNING. CHANGE OVER TO ALL SNOW IS MORE LIKELY TO OCCUR AT KIWD/KCMX. DRIER AIR WORKING IN BEHIND THE LOW LATE TUE AFTERNOON INTO TUE EVENING WILL END PCPN AND ALLOW ALL THE TAF SITES TO IMPROVE TO MVFR BY TUE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 421 PM EDT MON MAY 11 2015 ONGOING MARGINAL GALES OVER THE WRN PORTION OF LAKE SUPERIOR WILL CONTINUE TO DIMINISH...FALLING BLO GALE FORCE EARLY THIS EVENING... AS PRES GRADIENT WEAKENS AND WINDS BACK DUE TO LOW PRES SHIFTING ACROSS UPPER MI AND ERN LAKE SUPERIOR. ON THE BACK SIDE OF THE LOW...NNW WINDS WILL INCREASE TO 20-30KT ACROSS CNTRL AND ERN LAKE SUPERIOR LATE TONIGHT/TUE MORNING. MAY SEE A FEW GALE FORCE GUSTS TUE MORNING OVER SCNTRL LAKE SUPERIOR AROUND GRANITE ISLAND DUE TO LOCAL COASTAL CONVERGENCE. WINDS WILL DIMINISH FROM W TO E TUE AFTN/TUE NIGHT WITH LIGHT WINDS MOSTLY UNDER 15KT TO FOLLOW FOR WED/THU AS HIGH PRES BUILDS INTO THE UPPER LAKES WED AND THEN LINGERS INTO THU. AS THE HIGH PRES SHIFTS E AND A WEAK LOW PRES PASSES BY TO THE S...WINDS MAY INCREASE SOME FOR THU NIGHT/FRI BEFORE DIMINISHING AGAIN ON SAT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...VOSS MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1210 AM EDT TUE MAY 12 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 328 PM EDT MON MAY 11 2015 A COLD FRONT WILL COME THROUGH THE AREA TONIGHT ENDING OVER A WEEKS WORTH OF UNSEASONABLY WARM TEMPERATURES. THERE WILL BE SHOWERS AND A FEW THUNDERSTORMS AHEAD OF THE COLD FRONT THIS EVENING...THEN A FEW LIGHT RAIN SHOWERS TUESDAY AS CHILLY WESTERLY WINDS KEEP AFTERNOON TEMPERATURES IN THE 50S. SKIES WILL BECOME PARTLY CLOUDY TUESDAY NIGHT REMAIN SO ON WEDNESDAY. ANOTHER STORM SYSTEM WILL BRING MORE SHOWERS AND POSSIBLY THUNDERSTORMS LATER THIS WEEK INTO THE WEEKEND. IT WILL WARM UP AGAIN BY THE END TOO. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 328 PM EDT MON MAY 11 2015 THE MAIN ISSUE IS THE THREAT FOR SEVERE STORMS (NOT MUCH) THEN THE CHANCE FOR LIGHT RAIN SHOWERS TUESDAY AND POSSIBLE FROST TOMORROW NIGHT. THE LATEST RAP MODEL SHOWS THE LOW LEVEL JET CORE LIFTING NORTHEAST FROM SOUTHWEST LOWER MICHIGAN EARLY THIS AFTERNOON TO THE THUMB AREA BY EARLY THIS EVENING. THE MOST UNSTABLE CAPE (OVER 500 J/KG) STAYS JUST EAST OF OUR CWA LATE THIS AFTERNOON. WHILE THERE IS GOOD DEEP LAYER SHEAR...THE RAIN COOLED AIR OVER MOST OF OUR CWA WILL MITIGATE MOST OF THE SEVERE WEATHER THREAT. POSSIBLY ISOLATED DAMAGING WINDS COULD HAPPEN OVER OUR EXTREME SOUTHEAST COUNTIES EARLY THIS EVENING. OTHERWISE THE AREA OF RAIN WILL MOVE OUT BY MID EVENING. THEN THE DRY SLOT MOVES IN BEHIND THE COLD FRONT SO SKIES WILL CLEAR AT LEAST PARTLY. WE THEN GET WRAP AROUND COLD AIR ADVECTION INSTABILITY SHOWERS (MOSTLY SPRINKLES) TUESDAY AND IT WILL BE BREEZY AND CHILLY WITH HIGHS ONLY IN THE 50S. THE UPPER TROUGH MOVES OUT QUICKLY TUESDAY NIGHT ALLOWING FOR SOME CLEARING. FROST IS POSSIBLE OVER NORTHERN AREAS WEDNESDAY MORNING. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 328 PM EDT MON MAY 11 2015 AS HIGH PRESSURE MOVES EAST THURSDAY LOW PRESSURE WILL MOVE TOWARD THE GREAT LAKES. CONFIDENCE IS INCREASING THAT WE/LL SEE SOME PRECIPITATION MOVE OVER THE CWA THURSDAY NIGHT AND FRIDAY. ADDED THUNDER TO THE GRIDS FRIDAY AS LI/S FALL TO AROUND -2C AND CAPE INCREASES TO 1K J/KG. MUCH OF THE PCPN WILL BE EAST OF THE CWA BY SATURDAY AS THE SFC LOW MOVES AWAY. HOWEVER WE/LL KEEP LOW POPS IN TO COVER THE UPPER TROUGH. CHANCES FOR TSRA WILL INCREASE TOWARD THE BEGINNING OF NEXT WEEK AS A STRONGER COLD FRONT MOVES TOWARD THE CWA. STRONG SOUTH FLOW AHEAD OF IT WILL SEND ABUNDANT MOISTURE NORTHWARD AND CREATE SOME INSTABILITY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1209 AM EDT TUE MAY 12 2015 PREDOMINATELY VFR OVERNIGHT BUT AROUND 12Z TUESDAY MVFR CIGS WILL SPREAD IN FROM THE WEST AND PERSIST MUCH OF THE DAY. A FEW LIGHT SHOWERS OR SPRINKLES ARE POSSIBLE BUT IF ANY REDUCTIONS TO VSBYS OCCURRED IT SHOULD BE VERY BRIEF. CIGS ARE EXPECTED TO IMPROVE TO VFR AGAIN TUESDAY NIGHT AFTER 00-02Z. GUSTY SOUTHWEST TO WEST SFC WINDS OF 15 TO 25 KNOTS TONIGHT WILL INCREASE TO 20 TO 30 KNOTS ON TUESDAY... RESULTING IN SOME LOW LEVEL TURBULENCE. WINDS WILL DECREASE TUESDAY NIGHT AFTER 00-02Z. && .MARINE... ISSUED AT 328 PM EDT MON MAY 11 2015 THE STRONG WINDS BEHIND OUR SYSTEM WILL LEAD TO 4 TO 6 FOOT WAVES AND WINDS TO 30 KNOTS BY MID MORNING TUESDAY. AS A RESULT I ISSUED A SMALL CRAFT ADVISORY. && .HYDROLOGY... ISSUED AT 1222 PM EDT MON MAY 11 2015 ADDITIONAL RAINFALL AMOUNTS BETWEEN A QUARTER AND THREE QUARTERS OF AN INCH WILL BE POSSIBLE MAINLY BEFORE MIDNIGHT TONIGHT. WE ARE ISSUING ADVISORIES FOR THE SYCAMORE CREEK AT HOLT...WHICH SHOULD CREST SHORTLY AFTER MIDNIGHT TONIGHT. CONFIDENCE IS HIGH THAT IT WILL REMAIN BELOW FLOOD STAGE. AFTER TONIGHT DRY CONDITIONS SHOULD PREVAIL UNTIL THURSDAY...WHEN RAIN SHOWERS RETURN TO THE AREA. THIS SHOULD GIVE RIVER LEVELS SOME TIME TO SUBSIDE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY FROM 5 AM EARLY THIS MORNING TO 6 PM EDT THIS EVENING FOR LMZ844>849. && $$ SYNOPSIS...WDM SHORT TERM...WDM LONG TERM...93 AVIATION...MEADE HYDROLOGY...TJT MARINE...WDM
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1237 AM CDT TUE MAY 12 2015 .UPDATE... ISSUED AT 734 PM CDT MON MAY 11 2015 UPDATED POPS AS CURRENT RADAR TRENDS SHOW PRECIPITATION INCREASING IN COVERAGE AND INTENSITY ACROSS THE FORECAST AREA. AN AREA OF CONVECTIVE SHOWERS WITH REFLECTIVITY VALUES OVER 40 DBZ HAS DEVELOPED ABOUT 30 MILES NORTH OF DULUTH...ON THE LEADING EDGE OF THE H50 LOW/VORT MAX AND AN REGION OF LOW LEVEL FRONTOGENESIS DEPICTED IN THE LATEST RUC MESO ANALYSIS. ANTICIPATE ECHOES TO CONTINUE TO INTENSIFY OVER THE IRON RANGE/ARROWHEAD AS THE VORT MAX TRANSLATES EAST ACROSS THE FORECAST AREA. AT THIS TIME THE PRECIP TYPE BEING REPORTED BY AUTOMATED STATIONS IS ALL RAIN. HOWEVER...AS PROFILES COOL THROUGH THE EVENING THE RAIN IS EXPECTED TO CHANGE OVER TO SNOW FOR AT LEAST THE NORTHERN PORTION OF MN. ALSO ADDED AREAS OF FOG ALONG SOUTH SHORE OF LAKE SUPERIOR WHERE SURFACE OBSERVATIONS AND SPOTTERS HAVE REPORTED VISIBILITY OF LESS THAN A HALF MILE AT TIMES. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 328 PM CDT MON MAY 11 2015 A CLOSED AND NEARLY STACKED UPPER LOW OVER MINNESOTA WILL CONTINUE SHOWERS OVER THE REGION TONIGHT AS IT SLOWLY MOVES EAST. THE STRONGEST LIFT NORTH OF THE BAROCLINIC ZONE WILL BE IN NORTHERN MINNESOTA BUT CANNOT RULE OUT SHOWERS ACROSS REST OF THE FORECAST AREA. COLD AIR ADVECTION BEHIND THE LOW LATER TONIGHT COULD RESULT IN SNOW SHOWERS. BUT WITH THE WET GROUND, DO NOT EXPECT MUCH ACCUMULATION. THERE WILL BE A GRADUAL END TO ANY SHOWERS SLOWLY FORM WEST TO EAST TUESDAY WITH SFC HIGH PRESSURE BUILDING OVER THE AREA. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 328 PM CDT MON MAY 11 2015 THE NORTHLAND CAN EXPECT A BIT OF WET PATTERN OVER THE NEXT WEEK WITH SEVERAL OPPORTUNITIES FOR RAIN. HIGH PRESSURE WILL BE OVER THE NORTHLAND TUESDAY NIGHT AND WILL MAKE FOR A COOL AND RELATIVELY CLEAR NIGHT. TEMPERATURES WILL DIP INTO THE LOWER 30S AND UPPER 20S. THERE WILL BE INCREASING CLOUD COVER FROM THE WEST LATE TUESDAY NIGHT AND WEDNESDAY AS A MID LEVEL FRONTOGENETICAL BAND MOVES INTO THE NORTHLAND. THIS FRONTOGENETICAL BAND WILL LIKELY RESULT IN RAINS SHOWERS FOR PARTS OF THE NORTHLAND WEDNESDAY AND WEDNESDAY NIGHT. THE SW FORECAST AREA HAS THE BEST CHANCE OF RAIN. A LOW PRESSURE SYSTEM IN THE CENTRAL PLAINS WEDNESDAY NIGHT WILL LIFT INTO THE NORTHERN PLAINS THURSDAY AND THURSDAY NIGHT. THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THIS WILL BRING MORE RAIN TO THE NORTHLAND THURSDAY INTO FRIDAY. THE SOUTHERN FORECAST AREA HAS THE BEST CHANCE OF RAIN WITH THE PASSAGE OF THIS SYSTEM. WEAK HIGH PRESSURE WILL GIVE ANOTHER SHORT BREAK BETWEEN WEATHER SYSTEMS LATE FRIDAY AND SATURDAY. A LOW IN THE NORTHERN PLAINS WILL LIFT A WARM FRONT INTO THE UPPER MIDWEST. THE GFS AND ECMWF ARE IN RELATIVELY GOOD AGREEMENT THAT THE NORTHLAND WILL SEE SHOWERS AND STORMS LATE SATURDAY INTO EARLY MONDAY WITH THE PASSAGE OF THIS SYSTEM. THE SOUTHERN FORECAST AREA HAS THE BEST CHANCE OF SEEING THUNDER SINCE THE WARM FRONT MIGHT GET SHUNTED SOUTH BECAUSE OF COOL EASTERLY FLOW FROM LAKE SUPERIOR AND ONTARIO. HOWEVER...THERE COULD BE ELEVATED CONVECTION NORTH OF THE WARM FRONT...BUT THOUGHT IT TOO EARLY TO INCLUDE THUNDER OVER ALL OF THE NORTHLAND. TEMPERATURES WILL REMAIN COOL FOR THE MIDDLE OF THE WEEK...BUT WILL LIKELY REBOUND TO CLOSE TO NORMAL BY THIS WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1235 AM CDT TUE MAY 12 2015 WIDESPREAD RAIN/DRIZZLE...MIXING WITH SNOW AT TIMES...AND LIFR/IFR CONDITIONS WILL PREVAIL OVERNIGHT. CEILINGS WILL GRADUALLY IMPROVE FROM THE WEST THROUGH THE DAY AS DRIER AIR ASSOCIATED WITH BUILDING HIGH PRESSURE FILTERS INTO THE REGION. HOWEVER...THE COLD AIR MASS AND LINGERING MOISTURE WILL BE SUFFICIENT FOR INSTABILITY SHOWERS INTO THE AFTERNOON. A FEW OF THE SHOWERS WILL BE CAPABLE OF PRODUCING GUSTY NORTH WINDS TO 30 KT. && .PRELIMINARY POINT TEMPS/POPS... DLH 34 50 38 54 / 10 60 40 50 INL 30 56 40 58 / 10 0 50 50 BRD 37 52 46 59 / 10 60 50 60 HYR 31 56 43 61 / 10 40 30 50 ASX 32 52 39 57 / 10 40 40 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...GRANING SHORT TERM...CLC LONG TERM...GROCHOCINSKI AVIATION...CLC
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
843 PM MDT WED MAY 13 2015 .UPDATE... MID- AND HIGH-LEVEL CLOUD COVER EARLIER TODAY DELAYED AND REDUCED DESTABILIZATION...AND LARGE-SCALE FORCING WAS WEAK. THE RESULT IS WHAT WE SEE ON RADAR AT MID-EVENING...ONE BATCH OF STORMS CENTERED ACROSS WHEATLAND COUNTY AND REMNANTS OF CONVECTION WHICH FORMED ON THE BIGHORN MOUNTAINS FROM SHERIDAN TO LAME DEER. THERE/S NOT MUCH ELSE GOING ON...AND NEITHER RADAR TRENDS OR RECENT HRRR RUNS WOULD SUGGEST MUCH OTHER DEVELOPMENT OVERNIGHT. THUS...WE CHOSE TO LOWER POPS INTO THE SLIGHT CHANCE CATEGORY IN MANY AREAS LIKE BILLINGS WHILE MAINTAINING A BIT HIGHER POPS DOWNSTREAM OF CURRENT ACTIVITY. THE RISK OF STRONG STORMS IS WANING AND WILL DIMINISH BY ABOUT 10 PM MDT AS SURFACE-BASED INSTABILITY DECREASES. SCHULTZ && .SHORT TERM...VALID FOR THU AND FRI... A SHORTWAVE SEEN ON WATER VAPOR IMAGERY OVER NM THIS AFTERNOON WAS PUMPING MOISTURE NORTHWARD INTO THE FORECAST AREA IN THE FORM OF MID AND HIGH CLOUDS. THE CLOUDINESS SLOWED TEMPERATURE RISES...BUT RECENTLY THERE HAVE BEEN MORE SUNNY BREAKS AND READINGS HAVE CLIMBED INTO THE 60S. FURTHER S OVER WY...THERE WERE SCATTERED SHOWERS AND THUNDERSTORMS MOVING N. 19Z MESOANALYSIS DID NOT SHOW ANY APPRECIABLE SURFACE CAPE OVER THE FORECAST AREA. THE LATEST SREF DID SHOW A HIGH PROBABILITY OF 500 J/KG SURFACE CAPES BY 21Z OVER WESTERN AND SOUTH CENTRAL AREAS. THERE WAS A LOWER PROBABILITY OF 1000 J/KG OVER THESE AREAS AS WELL. THE SHEAR LOOKED MARGINAL FOR SEVERE WEATHER THIS AFTERNOON. SOME JET DIVERGENCE WILL MOVE THROUGH THE REGION THROUGH THIS EVENING AND WILL COMBINE WITH THE MOISTURE AND EASTERLY UPSLOPE FLOW TO BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA. PER THE ABOVE...THERE COULD BE AN ISOLATED STRONG/SEVERE STORM. THE AIRMASS WILL BECOME MORE STABLE AFTER 06Z...BUT STEEP MID/UPPER LEVEL LAPSE RATES WILL SUPPORT A SLIGHT CHANCE OF THUNDER. MORE JET DIVERGENCE WILL CROSS THE AREA THU AND THU NIGHT. THERE WILL ALSO BE A DIFFLUENT FLOW ALOFT AND LOW-LEVEL UPSLOPE FLOW... WITH INCREASING SHORTWAVES MOVING THROUGH THE FLOW. MOISTURE WILL CONTINUE TO INCREASE OVER THE AREA AS WELL. CAPES WILL BE SIMILAR TO TODAY/S EXPECTED VALUES AND THE SHEAR WILL BE SLIGHTLY HIGHER THAN TODAY/S SHEAR. MODELS HAD SOME LOW CHANCES OF PRECIPITATION OVER THE AREA THROUGH 18Z...THEN DEVELOPED PRECIPITATION ALONG THE TERRAIN THROUGH THE EVENING. THE QPF WILL SPREAD NE OVERNIGHT. ADJUSTED THE MORNING POPS A BIT...OTHERWISE KEPT THE POPS BASICALLY THE SAME AS THE PREVIOUS FORECAST THROUGH THU NIGHT. AGAIN...AN ISOLATED STRONG OR SEVERE STORM IS POSSIBLE IN THE AFTERNOON AND EVENING. TEMPERATURES ON THU WILL BE A LITTLE LOWER THAN TODAY/S HIGHS. MORE JET DIVERGENCE WILL CROSS THE AREA FRI AND FRI NIGHT AS THE BROAD W COAST UPPER LOW SHIFTS E. SHORTWAVE ENERGY WILL CONTINUE INCREASING OVER THE AREA AND AN 850 MB JET WILL INCREASE PRECIPITABLE WATERS TO AROUND 1 INCH OVER THE E HALF OF THE AREA. CAPES AND SHEAR WILL BE LOWER THAN RECENT DAYS. HAD MAINLY LIKELY POPS THROUGH THE PERIOD...EXCEPT LOWERED THEM ACROSS THE S LATE FRI NIGHT AS THE GFS TRIES TO BRING A DRY SLOT N INTO THE AREA. ALSO THERE WERE STILL SOME SUBTLE MODEL DIFFERENCES IN QPF AMOUNTS/PLACEMENT DURING FRI AND FRI NIGHT...SO DID NOT WANT TO GO CATEGORICAL AT THIS POINT. HAD JUST A SLIGHT MENTION OF THUNDER IN THE AFTERNOON AND EVENING. INHIBITED MIXING WILL LEAD TO HIGH TEMPERATURES IN THE 50S ON FRI. ARTHUR .LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED... CONFIDENCE REMAINS HIGH FOR A WET WEEKEND AND WELL BELOW NORMAL TEMPERATURES BUT THERE STILL REMAINS SOME UNCERTAINTY AS TO THE OVERALL EXTENT OF COVERAGE AND PRECIP AMOUNTS. MODELS KEEP A LARGE TROUGH ACROSS THE ENTIRE WESTERN U.S. SATURDAY INTO SUNDAY WITH SEVERAL UPPER LOWS OVER THE GREAT BASIN AND FOUR CORNERS REGION. THESE LOWS WILL SHIFT NORTHEAST SATURDAY BUT MODELS DIFFER IN THEIR PLACEMENT. THE GFS BRINGS THE LOW ACROSS OUR AREA INTO NORTHEAST MONTANA SHIFTING MOST IF NOT ALL THE PRECIP WITH IT SATURDAY LEAVING A MOSTLY DRY DAY. HOWEVER...THE ECMWF TAKES THE LOW INTO FAR SOUTHEAST MONTANA/NORTHEAST WYOMING RESULTING IN THE AREA OF PRECIP TO BE ACROSS MOST OF OUR FORECAST AREA. WILL CONTINUE TO TAKE A BLEND OF THE MODELS AS PRECIP AMOUNTS COULD STILL BE IN THE 1-3 INCH RANGE OVER A 3 DAY PERIOD FRIDAY THROUGH SUNDAY. GIVEN PLACEMENT OF THE LOW AND PRECIP AREAS...MODELS ALSO ARE OUT OF AGREEMENT WITH HIGH TEMPERATURES FOR SATURDAY...BASICALLY A 20 DEGREE DIFFERENCE FROM 48 WITH THE ECMWF TO 68 WITH THE MEX GUIDANCE. MODELS CONTINUE TO KICK THE LOWS EAST SUNDAY WHICH WOULD START A DRYING TREND FROM WEST TO EAST. PRESSURE GRADIENTS WILL BE TIGHT ACROSS THE CENTRAL AND ESPECIALLY EASTERN AREAS WHICH WILL RESULT IN VERY GUSTY NORTHERLY WINDS. THIS COMBINED WITH COOL TEMPERATURES SUNDAY WILL RESULT IN A BLUSTERY "COLD" DAY. 700MB TEMPERATURES WILL AGAIN SUPPORT SOME SNOW FOR THE MOUNTAINS BUT AMOUNTS ARE UNCERTAIN AT THIS TIME. MODELS THEN BRING ANOTHER UPPER LOW AND TROUGH ACROSS THE FORECAST AREA EARLY NEXT WEEK BRINGING CONTINUED PRECIP CHANCES. TEMPERATURES WILL BE BELOW NORMAL THROUGH THE ENTIRE EXTENDED PERIOD ESPECIALLY ON SUNDAY. HOOLEY && .AVIATION... AN AREA OF THUNDERSTORMS AROUND HARLOWTON WILL SLOWLY MOVE EAST AND WILL DISSIPATE BY AROUND MIDNIGHT. NO ACTIVITY EXPECTED TO IMPACT ANY TERMINALS. VFR CONDITIONS EXPECTED ACROSS THE AREA. SCATTERED THUNDERSTORMS WILL AGAIN BE POSSIBLE TOMORROW AFTERNOON. REIMER && .PRELIMINARY POINT TEMP/POPS... THU FRI SAT SUN MON TUE WED ----------------------------------------------------------- BIL 046/064 048/056 045/053 041/052 038/060 041/056 042/058 24/T 66/T 66/T 66/W 22/W 24/W 44/W LVM 040/063 044/056 040/052 038/054 034/058 037/055 038/060 25/T 56/T 67/T 66/W 23/W 33/W 44/W HDN 045/068 047/060 045/056 041/053 036/063 041/059 041/060 22/T 66/T 57/T 76/W 22/W 23/W 44/W MLS 045/067 046/058 046/058 042/054 035/060 040/058 041/059 31/B 35/T 78/T 76/W 22/W 23/W 44/W 4BQ 047/067 047/058 046/061 042/052 034/059 039/057 040/057 31/B 47/T 77/T 76/W 32/W 33/W 66/W BHK 043/063 042/058 045/062 041/051 032/056 037/057 038/056 42/W 15/T 78/T 87/W 32/W 23/W 55/W SHR 041/066 044/061 041/055 038/051 035/058 040/055 039/057 43/T 66/T 57/T 76/W 32/W 35/W 66/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1130 PM MDT MON MAY 11 2015 AVIATION SECTION UPDATED .DISCUSSION... UPDATE FORTHCOMING. SOUTHWEST FLOW ALOFT CONTINUES TO BRING MOISTURE AND INSTABILITY TO SOUTHWEST MONTANA WHERE SCATTERED SHOWERS SHOULD CONTINUE THROUGH THE NIGHT. BOTH THE HRRR AND RUC ANALYSIS BRING SHOWERS AS FAR NORTH AS JUST ABOUT GREAT FALLS BY 12Z. TEMPERATURES OVERNIGHT LOOK ON TRACK. && .AVIATION... UPDATED 0530Z. VFR CONDITIONS EXPECTED TONIGHT. SOUTHWEST FLOW ALOFT AHEAD OF A LOW PRESSURE SYSTEM ALONG THE OREGON COAST WILL PUSH EXTENSIVE MOISTURE INTO CENTRAL/SOUTHWEST MT TONIGHT. THIS WILL RESULT IN WIDESPREAD MID-LEVEL CEILINGS (GENERALLY IN THE 6000-10000 FT RANGE) AT ALL TAF SITES WITH ISOLATED -SHRA VCNTY KHLN/KBZN DEVELOPING AROUND 09-12Z. SCATTERED SHOWERS AND ISOLATED -TSRA BECOME MORE LIKELY FROM KHLN SOUTH TO THE MT/ID BORDER BY MID-AFTN AS THE COASTAL LOW COMES INLAND AND BRINGS ADDITIONAL MOISTURE AND INSTABILITY. BRIEF MVFR CEILINGS AND MODERATE RAINFALL POSSIBLE NEAR KHLN/KBZN WITH ANY STRONGER CONVECTIVE CELLS. WARANAUSKAS && .PREV DISCUSSION...ISSUED 259 PM MDT MON MAY 11 2015 MONDAY THROUGH WEDNESDAY...CONDITIONS WILL GENERALLY CHANGE TO A WETTER PATTERN THROUGH THE MIDDLE OF THE WEEK AS SHORTWAVE TROUGHS MOVE ONSHORE AND BEGIN TO BRING MOISTURE INTO THE REGION. SOME SHOWERS OVER THE HIGHER TERRAIN WILL BE POSSIBLE THIS EVENING AS THE FIRST SHORTWAVE MOVES INTO THE AREA. PRECIPITATION WILL BE LIMITED WITH THIS SYSTEM WITH MOST OF THE SHOWERS OCCURRING OVER THE ROCKY MOUNTAIN FRONT. THE NEXT SYSTEM WILL BEGIN TO MOVE INTO MONTANA TUESDAY NIGHT AND SHOULD BRING AN INCREASE IN SHOWERS AND THUNDERSTORMS TO THE AREA TUESDAY AFTERNOON AND EVENING. THIS EVENT LOOKS LIKE IT SHOULD BRING MORE WIDESPREAD PRECIPITATION TO THE AREA AS THE MOVES ACROSS THE STATE WEDNESDAY. PRECIPITATION IS EXPECTED TO DECREASE WEDNESDAY AFTERNOON AND EVENING. TEMPERATURES SHOULD COOL OFF TUESDAY AND WEDNESDAY BACK BELOW SEASONAL AVERAGES. SUK WEDNESDAY NIGHT THROUGH MONDAY. AT THIS TIME, FORECAST CONFIDENCE IS LOW FOR MUCH OF THIS PERIOD AS PRIMARY FORECAST MODELS NOT SHOWING MUCH CONSENSUS, ESPECIALLY ON PRECIPITATION COVERAGE AND AMOUNTS. THE MODEL DIFFERENCES CENTER ON THE EVOLUTION OF A BROAD SHORTWAVE TROF THAT WILL BE OFF THE CALIFORNIA COAST ON THURSDAY. MODELS ARE IN GENERALLY GOOD AGREEMENT THAT THE TROF WILL MAKE SLOW EASTWARD PROGRESS AND BE CENTERED OVER THE GREAT BASIN/DESERT SOUTHWEST BY LATE FRIDAY. PLUMES OF MOISTURE STREAMING NORTHWARD AHEAD OF THE TROF AXIS WILL BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS INTO MT BY THURS AFTN CONTINUING THRU FRIDAY, WITH THE ECMWF MODEL INDICATING MUCH WIDER PRECIP COVERAGE OVER CENTRAL/SOUTHWEST MT. THINGS GET MORE COMPLICATED OVER THE WEEKEND AS THE TROF LIFTS NORTHEASTWARD TOWARD THE CENTRAL ROCKIES. BOTH THE GFS AND EC MODELS SHIFT OUR WINDS ALOFT TO EASTERLY AS THE TROF PASSES TO OUR SOUTH, SETTING UP THE POSSIBILITY OF PULLING EXTENSIVE GULF OF MEXICO MOISTURE THROUGH THE UPPER MIDWEST AND INTO THE TREASURE STATE ON BOTH SAT/SUN. THE EC IS NOTABLY STRONGER WITH THIS LONG MOISTURE FETCH, DRIVEN MAINLY BY A CLOSED MID-LEVEL LOW PRESSURE AREA WITHIN THE TROF, WHEREAS THE GFS INDICATES AN OVERALL WEAKER TROF WITH LESS MOISTURE OVER OUR REGION. IN FACT, THE GFS HAS MUCH OF THE TROF AND PRECIPITATION OUT OF OUR AREA BY SUNDAY MORNING WHILE THE EC PAINTS EXTENSIVE RAINFALL WITH AMOUNTS RANGING FROM 0.1 INCH ALONG THE HI-LINE TO 0.5-0.75 INCH FROM GREAT FALLS SOUTHWARD TO THE IDAHO BORDER. GIVEN THE TROUBLESOME MODEL DIFFERENCES, THE CURRENT EXTENDED FORECAST LARGELY RELIES ON CLIMATOLOGICAL PRECIP PROBABILITIES (MOSTLY 30-40%) FOR SATURDAY AND EARLY SUNDAY, THEN REDUCES RAINFALL CHANCES SUN EVE INTO MONDAY AS THE TROF HEADS TOWARD THE GREAT LAKES STATES. THE GOOD NEWS IS THAT IT LOOKS THAT MOST/ALL OF THE FORECAST AREA SHOULD RECEIVE SOME NEEDED RAINFALL THIS WEEKEND; WE`LL JUST HAVE TO WAIT FOR ADDITIONAL MODEL OUTPUT TO GET A BETTER ESTIMATE ON AMOUNTS. AS FOR TEMPERATURES, THEY WILL REMAIN AT OR SLIGHTLY ABOVE SEASONAL VALUES THROUGH THE LATTER HALF OF THE WEEK, WITH HIGHS IN THE MID- AND UPPER 60S EACH DAY. WARANAUSKAS && .PRELIMINARY POINT TEMPS/POPS... GTF 36 60 41 59 / 10 20 30 60 CTB 30 56 35 51 / 10 10 20 70 HLN 40 61 41 65 / 30 30 40 50 BZN 38 60 38 66 / 20 20 50 40 WEY 30 62 31 61 / 30 40 40 30 DLN 41 62 41 67 / 20 40 50 40 HVR 33 63 36 59 / 10 10 20 60 LWT 37 59 39 63 / 20 20 30 50 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
606 PM CDT WED MAY 13 2015 .SHORT TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 305 PM CDT WED MAY 13 2015 TONIGHT LATEST SHORT TERM PROGS IN AGREEMENT SHOWING THAT GOING RAINFALL FCST FOR TONIGHT IS ON TRACK WITH PCPN ACTIVITY DEVELOPING OVER KS THEN EXPANDING NWD INTO THE CWA EARLY THIS EVENING. GIVEN COMBINATION OF UPPER SUPPORT VIA POTENT VORT MAX/STRONG DIVG WORKING IN TANDEM WITH RATHER MOIST 305K UPGLIDE...SEEMS REASONABLE TO ASSUME THAT SEVERAL LOCATIONS SHOULD SEE RAINFALL TOTALS OF AT LEAST HALF AN INCH MAINLY OVER THE SRN CWA WHERE LIFT/MOISTURE WILL BE MORE PREVALENT. IN ADDITION...MODELS ARE SHOWING INSTABILITY PARAMETERS WILL BE WEAK AT BEST SO ANY TSTM DEVELOPMENT SHOULD BE ISOLATED. DEE THURSDAY THROUGH SATURDAY TIMING AND POTENTIAL FOR SEVERE STORMS BOTH FRIDAY AND SATURDAY WILL BE THE MAIN FORECAST CONCERNS. OUR AREA WILL GENERALLY BE IN SOUTH OR SOUTHWEST MID TROPOSPHERIC FLOW THE NEXT FEW DAYS. WATER VAPOR IMAGERY EARLY THIS WEDNESDAY AFTERNOON...IN COMBINATION WITH EARLY AFTERNOON RAP MODEL INTITIALIZATIONS...SHOWED FAIRLY IMPRESSIVE SHORTWAVE TROUGH FROM COLORADO DOWN INTO WEST TEXAS. THIS WILL LIFT NORTHEAST ACROSS THE AREA TONIGHT AND THURSDAY. BRIEF SHORTWAVE RIDGING BUILDS IN FOR LATE THURSDAY/EARLY THURSDAY NIGHT...WHILE A STRONG CLOSED LOW DIGS DOWN INTO NEVADA AND CALIFORNIA. GENERAL MODEL CONSENSUS SHOWS THE CENTER OF THAT 500 MB LOW SHOULD LIFT OUT INTO NORTHEAST WYOMING OR SOUTHEAST MONTANA BY SATURDAY EVENING. THURSDAY...SHOWERS WILL LINGER AT LEAST IN THE MORNING...WITH ISOLATED THUNDER POSSIBLE. CHANCES DECREASE THROUGH THE AFTERNOON. EXPECT AT LEAST THE SOUTHWEST HALF OF OUR FORECAST AREA TO SEE SOME AFTERNOON SUNSHINE AND THAT SHOULD HELP PUSH HIGHS INTO THE 70S THERE. AREAS FROM AROUND YANKTON DOWN TO ONAWA...HARLAN AND RED OAK MAY ONLY TOP OUT FROM 65 TO 70. PCPN AMOUNTS THURSDAY ARE EXPECTED TO BE MOSTLY UNDER 0.25 INCHES. A WEAK COLD FRONT WILL SETTLE DOWN INTO THE FORECAST AREA THURSDAY NIGHT AND THEN STALL. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND NORTH OF THE BOUNDARY THURSDAY NIGHT AS THE LOW LEVEL JET INCREASES AND CAUSES ISENTROPIC LIFT. BEST FOCUS SEEMS TO BE OVER SOUTHEAST NEBRASKA. FRIDAY AND FRIDAY NIGHT WILL BE INTERESTING. SOUTHERLY LOW LEVEL FLOW INCREASES AS LOW PRESSURE INITIALLY OVER NORTHEAST COLORADO AT 12Z FRIDAY LIFTS NORTH TO WEST/NORTHWEST OF VALENTINE BY 06Z SATURDAY. HIGHS FRIDAY SHOULD REACH 75 TO 80...PUSHING BOUNDARY LAYER CAPE VALUES INTO THE 1500 TO 3000 J/KG RANGE. 0-6 KM AGL BULK SHEAR VALUES SHOULD BE MOSTLY 25-40 KNOTS. STORMS MAY INITIALLY BE MOSTLY NORTH OF THE FRONT...BUT THEN COULD ALSO DEVELOP IN THE WARM SECTOR OR FARTHER BACK TO THE WEST IN CENTRAL NEBRASKA LATER IN THE DAY. DETAILS SHOULD BECOME MORE CLEAR WITH THURSDAY MODEL RUNS ON THE LOCATION OF FRONTAL BOUNDARIES WHICH WILL HELP FOCUS THE ACTIVITY IN THE AFTERNOON AND EVENING. STORM COVERAGE MAY DROP OFF DRASTICALLY AFTER MIDNIGHT. SATURDAY...OVERALL PARAMETERS ARE EXPECTED TO BE IN PLACE FOR ANOTHER POSSIBLE SEVERE EVENT...BUT NOT COMPLETELY SOLD ON THAT SINCE IT WILL AT LEAST SOMEWHAT DEPEND ON WHAT HAPPENS FRIDAY. MID LEVEL WINDS SHOULD INCREASE AND THEREFORE BULK SHEAR VALUES MAY END UP HIGHER THAN THOSE FRIDAY. TIMING OF CONVECTION WILL BE THE KEY. MILLER .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 305 PM CDT WED MAY 13 2015 STORMS SHOULD LINGER INTO SATURDAY NIGHT...WITH SHOWERS/A FEW EMBEDDED STORMS POSSIBLE SUNDAY MORNING. THE 12Z GFS WAS MOSTLY DRY IN OUR AREA SUNDAY...BUT THE 12Z ECMWF WAS ABOUT 6 HOURS SLOWER LIFTING PCPN OUT OF THE AREA. SO...FOR NOW WE HAVE KEPT SOME LOW POPS SUNDAY IN OUR NORTHERN ZONES SUNDAY. SUNDAY NIGHT THROUGH TUESDAY SHOULD BE LESS ACTIVE AS HIGH PRESSURE BUILDS INTO THE REGION WITH COOL TEMPERATURES. SOME LOWS COULD DROP DOWN TO NEAR 40. IT APPEARS THAT CHANCES FOR SHOWERS/STORMS WILL INCREASE AGAIN BY TUESDAY NIGHT AND WEDNESDAY AS SHORTWAVE ENERGY MOVES IN FROM THE WEST/SOUTHWEST. MILLER && .AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 605 PM CDT WED MAY 13 2015 RAIN IS BEGINNING TO OVERSPREAD THE AREA AND WILL LAST INTO THURSDAY MORNING. VFR CIGS WILL DETERIORATE TO MVFR/IFR ALONG WITH SOME MVFR VSBYS. CIGS WILL BEGIN TO IMPROVE FROM WEST TO EAST 21-00Z. BRISK SOUTHEAST WINDS 8 TO 18KTS THROUGH THURSDAY MORNING WILL DECREASE TO 10KTS OR LESS THURSDAY AFTERNOON. WILL MENTION LLWS AT KOMA AND KLNK 02Z-12Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DEE/MILLER LONG TERM...MILLER AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1238 PM CDT TUE MAY 12 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT TUE MAY 12 2015 HIGH PRESSURE CENTERED ACROSS KS MOVES EAST INTO MISSOURI TODAY. LOW PRESSURE WILL BEGIN TO ORGANIZE ACROSS THE NRN HIGH PLAINS THIS AFTERNOON. THE MODEL CONSENSUS SHOWS STRONG RETURN FLOW DEVELOPING THIS AFTERNOON WITH SOUTH WINDS INCREASING TO 20 TO 30 MPH ACROSS WRN NEB. THESE WINDS SHOULD CONTINUE TONIGHT AS THE LOW LEVEL JET FORMS AND STRENGTHENS TO AROUND 50 KT. THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARMER SIDE OF THE MODEL CONSENSUS. SEVERAL MODELS WERE VERY COLD WITH HIGHS IN THE 60S WHILE THE RAP WAS VERY WARM WITH HIGHS IN THE UPPER 70S. THE FORECAST IS FOR HIGHS IN THE UPPER 60S TO MID 70S. LOWS TONIGHT FALL INTO THE UPPER 40S TO AROUND 50. SOUTH WINDS AT 15 TO 20 MPH SHOULD KEEPS LOWS MILD. LASTLY...THE MODELS SHOW A WEAK DISTURBANCE FIRING THUNDERSTORMS ON THE LARAMIE AND FRONT RANGES LATE THIS AFTERNOON AROUND 21Z WHICH CARRY EAST TOWARD WESTERN NEBRASKA. THE BEST GUESS IS FOR ISOLATED SPRINKLES THIS EVENING. THE GFS WAS THE WET MODEL WHICH ACTUALLY SHOWS SOME MEASURABLE QPF. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 359 AM CDT TUE MAY 12 2015 MODELS CONTINUE TO ADVERTISE A RAPID RETURN OF GULF MOISTURE TAKING PLACE WEDNESDAY...WITH MODELS PROJECTING 850 MB DEW POINTS IN THE 10 TO 12C RANGE BY WEDNESDAY EVENING ACROSS THE REGION. A LARGE UPPER TROUGH WILL BE TAKING SHAPE ALONG THE WEST COAST MID TO LATE WEEK...WITH A LEAD SHORTWAVE EJECTING NORTHEAST THROUGH THE PLAINS AHEAD OF THE TROUGH WEDNESDAY NIGHT INTO THURSDAY. THIS SYSTEM IS SHOWN TO HAVE SOMEWHAT OF A NEGATIVE TILT...WHICH WILL HELP DRAW MOISTURE WESTWARD INTO THE HIGH PLAINS. THE COMBINATION OF STRONG LIFT AND MOISTURE TRANSPORT ON A SOUTHERLY LOW LEVEL JET...CONTINUES TO GIVE CONFIDENCE THAT PRECIPITATION SHOULD RESULT LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. WILL MAINTAIN THE LIKELY POPS ALONG AND EAST OF HIGHWAY 83 WEDNESDAY NIGHT...AND ALSO INTRODUCE EVENING LIKELY POPS ALONG A SURFACE TROUGH ACROSS THE PANHANDLE INTO THE WESTERN SANDHILLS. THE LEAD WAVE QUICKLY PASSES AND MOVES NORTHEAST AWAY FROM THE AREA THURSDAY. ATTENTION THEN TURNS TO THE LONG WAVE TROUGH ALONG THE WEST COAST. MODELS/ENSEMBLES PROJECT THIS TO MOVE EAST AS A CLOSED SYSTEM DURING THE WEEKEND. THE GENERAL CONSENSUS IN THE MODELS AND ENSEMBLE MEAN IS FOR THE CENTER OF THE SYSTEM TO TRACK ACROSS WYOMING INTO SOUTH DAKOTA. THIS PUTS OUR AREA IN THE WARM MOIST SECTOR. INSTABILITY LOOKS TO BE STRONG...AND AS DEEP LAYER SHEAR INCREASES...STRONG TO SEVERE STORMS WILL LIKELY RESULT. WILL INTRODUCE THE POTENTIAL FOR SEVERE THUNDERSTORMS IN THE HAZARDOUS WEATHER OUTLOOK FOR FRIDAY AND SATURDAY. THE GFS AND ECMWF CONTINUE TO DIFFER SOMEWHAT ON THE LOW LEVEL BOUNDARY PLACEMENT...BUT THE LATEST TREND IS TO HOLD THE DRY LINE BACK TO THE WEST ACROSS WESTERN NEBRASKA INTO WESTERN KANSAS...WHICH WOULD PLACE SEVERE STORM DEVELOPMENT ACROSS THE FORECAST AREA OF WESTERN AND NORTH CENTRAL NEBRASKA. WE WILL LIKELY BE IN THE MIDST OF THE MID LEVEL DRY SLOT SUNDAY AS THE STORM SYSTEM CROSSES THE DAKOTAS...BUT AT LEAST SOME CHANCE FOR SHOWERS IN WRAP AROUND PATTERN ACROSS NORTHERN NEBRASKA. DRY WEATHER FOR MONDAY...THEN MORE CHANCES FOR RAIN NEXT WEEK BEYOND THE FORECAST PERIOD...AS THE NEXT DEEP TROUGH MOVES EAST INTO THE WESTERN CONUS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1238 PM CDT TUE MAY 12 2015 FOR THE 18Z KLBF AND KVTN TAF...HIGH PRESSURE WILL BUILD EAST ACROSS THE MID-MISSISSIPPI VALLEY WITH A BROAD AREA OF LOW PRESSURE DEVELOPING WEST OF THE ROCKIES. THIS WILL INCREASE THE PRESSURE GRADIENT ACROSS WEST CENTRAL NEBRASKA...PROVIDING FOR INCREASING SOUTHERLY WINDS...WHICH WILL CONTINUE THROUGH THE OVERNIGHT HOURS. LLWS MAY BECOME TROUBLESOME ACROSS OUR EASTERN ZONES OVERNIGHT...MAINLY IMPACTING KONL...KBBW...AND POSSIBLY KLBF. OTHERWISE INCREASING CLOUDINESS EARLY ON WEDNESDAY WILL LEAD TO OVC SKIES BY EARLY AFTERNOON. && .HYDROLOGY... ISSUED AT 359 AM CDT TUE MAY 12 2015 THE COMBINATION OF SEASONAL SNOW MELT IN THE UPPER SOUTH PLATTE RIVER BASIN AND RECENT HEAVY PRECIPITATION OVER WESTERN NEBRASKA AND NORTHEAST COLORADO WILL LEAD TO FLOODING ON THE SOUTH PLATTE AND PLATTE RIVERS IN SOUTHWEST NEBRASKA LATER THIS WEEK AND INTO EARLY NEXT WEEK. AT THIS TIME SOME UNCERTAINTY STILL REMAINS WITH THE FORECAST AS KEY UPSTREAM GAUGES IN NORTHEAST COLORADO HAVE YET TO CREST. HOWEVER...LATEST PROJECTIONS CONTINUE TO HIGHLIGHT AN INCREASING THREAT FOR SIGNIFICANT FLOODING TO OCCUR...POTENTIALLY NEAR SEPTEMBER 2013 FLOOD LEVELS. RIVER STAGE FORECASTS WILL BE CLOSELY MONITORED AND UPDATED ONCE MORE UPSTREAM RIVER DATA BECOMES AVAILABLE. PERSONS THAT LIVE IN VULNERABLE AREAS ALONG THE SOUTH PLATTE RIVER AND PLATTE RIVER IN SOUTHWEST NEBRASKA SHOULD PAY CLOSE ATTENTION TO FLOOD FORECASTS IN THE COMING DAYS AND BE PREPARED TO TAKE PROPER ACTION. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...JACOBS HYDROLOGY...MARTIN/TAYLOR
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
630 AM CDT TUE MAY 12 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT TUE MAY 12 2015 HIGH PRESSURE CENTERED ACROSS KS MOVES EAST INTO MISSOURI TODAY. LOW PRESSURE WILL BEGIN TO ORGANIZE ACROSS THE NRN HIGH PLAINS THIS AFTERNOON. THE MODEL CONSENSUS SHOWS STRONG RETURN FLOW DEVELOPING THIS AFTERNOON WITH SOUTH WINDS INCREASING TO 20 TO 30 MPH ACROSS WRN NEB. THESE WINDS SHOULD CONTINUE TONIGHT AS THE LOW LEVEL JET FORMS AND STRENGTHENS TO AROUND 50 KT. THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARMER SIDE OF THE MODEL CONSENSUS. SEVERAL MODELS WERE VERY COLD WITH HIGHS IN THE 60S WHILE THE RAP WAS VERY WARM WITH HIGHS IN THE UPPER 70S. THE FORECAST IS FOR HIGHS IN THE UPPER 60S TO MID 70S. LOWS TONIGHT FALL INTO THE UPPER 40S TO AROUND 50. SOUTH WINDS AT 15 TO 20 MPH SHOULD KEEPS LOWS MILD. LASTLY...THE MODELS SHOW A WEAK DISTURBANCE FIRING THUNDERSTORMS ON THE LARAMIE AND FRONT RANGES LATE THIS AFTERNOON AROUND 21Z WHICH CARRY EAST TOWARD WESTERN NEBRASKA. THE BEST GUESS IS FOR ISOLATED SPRINKLES THIS EVENING. THE GFS WAS THE WET MODEL WHICH ACTUALLY SHOWS SOME MEASURABLE QPF. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 359 AM CDT TUE MAY 12 2015 MODELS CONTINUE TO ADVERTISE A RAPID RETURN OF GULF MOISTURE TAKING PLACE WEDNESDAY...WITH MODELS PROJECTING 850 MB DEW POINTS IN THE 10 TO 12C RANGE BY WEDNESDAY EVENING ACROSS THE REGION. A LARGE UPPER TROUGH WILL BE TAKING SHAPE ALONG THE WEST COAST MID TO LATE WEEK...WITH A LEAD SHORTWAVE EJECTING NORTHEAST THROUGH THE PLAINS AHEAD OF THE TROUGH WEDNESDAY NIGHT INTO THURSDAY. THIS SYSTEM IS SHOWN TO HAVE SOMEWHAT OF A NEGATIVE TILT...WHICH WILL HELP DRAW MOISTURE WESTWARD INTO THE HIGH PLAINS. THE COMBINATION OF STRONG LIFT AND MOISTURE TRANSPORT ON A SOUTHERLY LOW LEVEL JET...CONTINUES TO GIVE CONFIDENCE THAT PRECIPITATION SHOULD RESULT LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. WILL MAINTAIN THE LIKELY POPS ALONG AND EAST OF HIGHWAY 83 WEDNESDAY NIGHT...AND ALSO INTRODUCE EVENING LIKELY POPS ALONG A SURFACE TROUGH ACROSS THE PANHANDLE INTO THE WESTERN SANDHILLS. THE LEAD WAVE QUICKLY PASSES AND MOVES NORTHEAST AWAY FROM THE AREA THURSDAY. ATTENTION THEN TURNS TO THE LONG WAVE TROUGH ALONG THE WEST COAST. MODELS/ENSEMBLES PROJECT THIS TO MOVE EAST AS A CLOSED SYSTEM DURING THE WEEKEND. THE GENERAL CONSENSUS IN THE MODELS AND ENSEMBLE MEAN IS FOR THE CENTER OF THE SYSTEM TO TRACK ACROSS WYOMING INTO SOUTH DAKOTA. THIS PUTS OUR AREA IN THE WARM MOIST SECTOR. INSTABILITY LOOKS TO BE STRONG...AND AS DEEP LAYER SHEAR INCREASES...STRONG TO SEVERE STORMS WILL LIKELY RESULT. WILL INTRODUCE THE POTENTIAL FOR SEVERE THUNDERSTORMS IN THE HAZARDOUS WEATHER OUTLOOK FOR FRIDAY AND SATURDAY. THE GFS AND ECMWF CONTINUE TO DIFFER SOMEWHAT ON THE LOW LEVEL BOUNDARY PLACEMENT...BUT THE LATEST TREND IS TO HOLD THE DRY LINE BACK TO THE WEST ACROSS WESTERN NEBRASKA INTO WESTERN KANSAS...WHICH WOULD PLACE SEVERE STORM DEVELOPMENT ACROSS THE FORECAST AREA OF WESTERN AND NORTH CENTRAL NEBRASKA. WE WILL LIKELY BE IN THE MIDST OF THE MID LEVEL DRY SLOT SUNDAY AS THE STORM SYSTEM CROSSES THE DAKOTAS...BUT AT LEAST SOME CHANCE FOR SHOWERS IN WRAP AROUND PATTERN ACROSS NORTHERN NEBRASKA. DRY WEATHER FOR MONDAY...THEN MORE CHANCES FOR RAIN NEXT WEEK BEYOND THE FORECAST PERIOD...AS THE NEXT DEEP TROUGH MOVES EAST INTO THE WESTERN CONUS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 630 AM CDT TUE MAY 12 2015 VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. STRONG SOUTH WINDS DEVELOP TODAY INCREASING TO 18020G32KT. ISOLATED TSTMS ARE EXPECTED ACROSS THE LARAMIE AND COLORADO FRONT RANGES AOA 21Z THIS AFTN. THERE IS A SLIGHT CHANCE THESE STORMS COULD REACH WRN NEB THIS EVENING IN THE FORM OF -SHRA/SPRINKLES. && .HYDROLOGY... ISSUED AT 359 AM CDT TUE MAY 12 2015 THE COMBINATION OF SEASONAL SNOW MELT IN THE UPPER SOUTH PLATTE RIVER BASIN AND RECENT HEAVY PRECIPITATION OVER WESTERN NEBRASKA AND NORTHEAST COLORADO WILL LEAD TO FLOODING ON THE SOUTH PLATTE AND PLATTE RIVERS IN SOUTHWEST NEBRASKA LATER THIS WEEK AND INTO EARLY NEXT WEEK. AT THIS TIME SOME UNCERTAINTY STILL REMAINS WITH THE FORECAST AS KEY UPSTREAM GAUGES IN NORTHEAST COLORADO HAVE YET TO CREST. HOWEVER...LATEST PROJECTIONS CONTINUE TO HIGHLIGHT AN INCREASING THREAT FOR SIGNIFICANT FLOODING TO OCCUR...POTENTIALLY NEAR SEPTEMBER 2013 FLOOD LEVELS. RIVER STAGE FORECASTS WILL BE CLOSELY MONITORED AND UPDATED ONCE MORE UPSTREAM RIVER DATA BECOMES AVAILABLE. PERSONS THAT LIVE IN VULNERABLE AREAS ALONG THE SOUTH PLATTE RIVER AND PLATTE RIVER IN SOUTHWEST NEBRASKA SHOULD PAY CLOSE ATTENTION TO FLOOD FORECASTS IN THE COMING DAYS AND BE PREPARED TO TAKE PROPER ACTION. && .LBF WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR NEZ006>010-026>029-038-058-059-069>071. FREEZE WARNING UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR NEZ004- 005-022>025-035>037-056-057-094. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC HYDROLOGY...MARTIN/TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
411 AM CDT TUE MAY 12 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT TUE MAY 12 2015 HIGH PRESSURE CENTERED ACROSS KS MOVES EAST INTO MISSOURI TODAY. LOW PRESSURE WILL BEGIN TO ORGANIZE ACROSS THE NRN HIGH PLAINS THIS AFTERNOON. THE MODEL CONSENSUS SHOWS STRONG RETURN FLOW DEVELOPING THIS AFTERNOON WITH SOUTH WINDS INCREASING TO 20 TO 30 MPH ACROSS WRN NEB. THESE WINDS SHOULD CONTINUE TONIGHT AS THE LOW LEVEL JET FORMS AND STRENGTHENS TO AROUND 50 KT. THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARMER SIDE OF THE MODEL CONSENSUS. SEVERAL MODELS WERE VERY COLD WITH HIGHS IN THE 60S WHILE THE RAP WAS VERY WARM WITH HIGHS IN THE UPPER 70S. THE FORECAST IS FOR HIGHS IN THE UPPER 60S TO MID 70S. LOWS TONIGHT FALL INTO THE UPPER 40S TO AROUND 50. SOUTH WINDS AT 15 TO 20 MPH SHOULD KEEPS LOWS MILD. LASTLY...THE MODELS SHOW A WEAK DISTURBANCE FIRING THUNDERSTORMS ON THE LARAMIE AND FRONT RANGES LATE THIS AFTERNOON AROUND 21Z WHICH CARRY EAST TOWARD WESTERN NEBRASKA. THE BEST GUESS IS FOR ISOLATED SPRINKLES THIS EVENING. THE GFS WAS THE WET MODEL WHICH ACTUALLY SHOWS SOME MEASURABLE QPF. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 359 AM CDT TUE MAY 12 2015 MODELS CONTINUE TO ADVERTISE A RAPID RETURN OF GULF MOISTURE TAKING PLACE WEDNESDAY...WITH MODELS PROJECTING 850 MB DEW POINTS IN THE 10 TO 12C RANGE BY WEDNESDAY EVENING ACROSS THE REGION. A LARGE UPPER TROUGH WILL BE TAKING SHAPE ALONG THE WEST COAST MID TO LATE WEEK...WITH A LEAD SHORTWAVE EJECTING NORTHEAST THROUGH THE PLAINS AHEAD OF THE TROUGH WEDNESDAY NIGHT INTO THURSDAY. THIS SYSTEM IS SHOWN TO HAVE SOMEWHAT OF A NEGATIVE TILT...WHICH WILL HELP DRAW MOISTURE WESTWARD INTO THE HIGH PLAINS. THE COMBINATION OF STRONG LIFT AND MOISTURE TRANSPORT ON A SOUTHERLY LOW LEVEL JET...CONTINUES TO GIVE CONFIDENCE THAT PRECIPITATION SHOULD RESULT LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. WILL MAINTAIN THE LIKELY POPS ALONG AND EAST OF HIGHWAY 83 WEDNESDAY NIGHT...AND ALSO INTRODUCE EVENING LIKELY POPS ALONG A SURFACE TROUGH ACROSS THE PANHANDLE INTO THE WESTERN SANDHILLS. THE LEAD WAVE QUICKLY PASSES AND MOVES NORTHEAST AWAY FROM THE AREA THURSDAY. ATTENTION THEN TURNS TO THE LONG WAVE TROUGH ALONG THE WEST COAST. MODELS/ENSEMBLES PROJECT THIS TO MOVE EAST AS A CLOSED SYSTEM DURING THE WEEKEND. THE GENERAL CONSENSUS IN THE MODELS AND ENSEMBLE MEAN IS FOR THE CENTER OF THE SYSTEM TO TRACK ACROSS WYOMING INTO SOUTH DAKOTA. THIS PUTS OUR AREA IN THE WARM MOIST SECTOR. INSTABILITY LOOKS TO BE STRONG...AND AS DEEP LAYER SHEAR INCREASES...STRONG TO SEVERE STORMS WILL LIKELY RESULT. WILL INTRODUCE THE POTENTIAL FOR SEVERE THUNDERSTORMS IN THE HAZARDOUS WEATHER OUTLOOK FOR FRIDAY AND SATURDAY. THE GFS AND ECMWF CONTINUE TO DIFFER SOMEWHAT ON THE LOW LEVEL BOUNDARY PLACEMENT...BUT THE LATEST TREND IS TO HOLD THE DRY LINE BACK TO THE WEST ACROSS WESTERN NEBRASKA INTO WESTERN KANSAS...WHICH WOULD PLACE SEVERE STORM DEVELOPMENT ACROSS THE FORECAST AREA OF WESTERN AND NORTH CENTRAL NEBRASKA. WE WILL LIKELY BE IN THE MIDST OF THE MID LEVEL DRY SLOT SUNDAY AS THE STORM SYSTEM CROSSES THE DAKOTAS...BUT AT LEAST SOME CHANCE FOR SHOWERS IN WRAP AROUND PATTERN ACROSS NORTHERN NEBRASKA. DRY WEATHER FOR MONDAY...THEN MORE CHANCES FOR RAIN NEXT WEEK BEYOND THE FORECAST PERIOD...AS THE NEXT DEEP TROUGH MOVES EAST INTO THE WESTERN CONUS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1120 PM CDT MON MAY 11 2015 EXCEPT FOR A BRIEF PERIOD OF MIDDLE CLOUD CEILINGS 10-14Z... UNLIMITED CEILING AND VISIBILITY ARE FORECAST TO CONTINUE TONIGHT AND TUESDAY THROUGH LATE TUESDAY EVENING. VARIABLE WIND IS EXPECTED TONIGHT AS HIGH PRESSURE DRIFTS TO THE EAST AND WIND SWINGS AROUND TO THE SOUTH. WIND WILL INCREASE TUESDAY MORNING AND...BY 15Z...IS EXPECTED TO BE 150-180 AT 12-15G20-24. THE WIND IS THEN EXPECTED TO CONTINUE INCREASING...BECOMING 160-180 AT 18-22G28-32KT. AFTER 00Z...THE WIND WILL DECREASE TO 12-14G20-22KT. && .HYDROLOGY... ISSUED AT 359 AM CDT TUE MAY 12 2015 THE COMBINATION OF SEASONAL SNOW MELT IN THE UPPER SOUTH PLATTE RIVER BASIN AND RECENT HEAVY PRECIPITATION OVER WESTERN NEBRASKA AND NORTHEAST COLORADO WILL LEAD TO FLOODING ON THE SOUTH PLATTE AND PLATTE RIVERS IN SOUTHWEST NEBRASKA LATER THIS WEEK AND INTO EARLY NEXT WEEK. AT THIS TIME SOME UNCERTAINTY STILL REMAINS WITH THE FORECAST AS KEY UPSTREAM GAUGES IN NORTHEAST COLORADO HAVE YET TO CREST. HOWEVER...LATEST PROJECTIONS CONTINUE TO HIGHLIGHT AN INCREASING THREAT FOR SIGNIFICANT FLOODING TO OCCUR...POTENTIALLY NEAR SEPTEMBER 2013 FLOOD LEVELS. RIVER STAGE FORECASTS WILL BE CLOSELY MONITORED AND UPDATED ONCE MORE UPSTREAM RIVER DATA BECOMES AVAILABLE. PERSONS THAT LIVE IN VULNERABLE AREAS ALONG THE SOUTH PLATTE RIVER AND PLATTE RIVER IN SOUTHWEST NEBRASKA SHOULD PAY CLOSE ATTENTION TO FLOOD FORECASTS IN THE COMING DAYS AND BE PREPARED TO TAKE PROPER ACTION. && .LBF WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR NEZ006>010-026>029-038-058-059-069>071. FREEZE WARNING UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR NEZ004- 005-022>025-035>037-056-057-094. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...SPRINGER HYDROLOGY...MARTIN/TAYLOR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1242 AM CDT TUE MAY 12 2015 .UPDATE... ISSUED AT 1242 AM CDT TUE MAY 12 2015 TEMPS ARE FALLING SLOWLY AS WINDS ARE STILL 5-7 KTS MOST LOCATIONS. 04Z HRRR INDICATES THE SFC RIDGE AXIS WILL MOVE THRU RIGHT AROUND DAWN. WINDS SHOULD THEN DROP OFF AND ALLOW TEMPS TO REACH THE LOW-MID 30S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 1242 AM CDT TUE MAY 12 2015 THIS SERVES AS THE FIRST DRAFT FOR THIS SHIFT... ALOFT: HEIGHTS WILL CONT TO RISE TODAY. WNW FLOW WILL TRANSITION TO WSW TONIGHT AS A SHORTWAVE RIDGE PASSES THRU. SURFACE: HIGH PRES WAS OVER KS AT 08Z AND WILL DRIFT E OF THE REGION TODAY. MEANWHILE...LOW PRES WILL CONT ORGANIZING OVER THE INTERMOUNTAIN W THRU TONIGHT. RETURN FLOW WILL RESULT WITH A TIGHTENING PRES GRAD. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 339 PM CDT MON MAY 11 2015 A LARGE AREA OF LOW PRESSURE WILL DROP SOUTH ACROSS THE WESTERN STATES OVER THE MIDDLE OF THE WEEK...RESULTING IN GENERALLY SOUTHWESTERLY FLOW ALOFT AND MULTIPLE CHANCES FOR THUNDERSTORMS BEGINNING WEDNESDAY AFTERNOON. TEMPERATURE WISE...GENERALLY MILD CONDITIONS ARE EXPECTED THROUGH THE EXTENDED PERIODS...WITH TEMPERATURES EXPECTED TO BE NEAR OR ABOVE CLIMATOLOGY EACH DAY. STARTING WEDNESDAY...EXPECT A WEAK UPPER LEVEL DISTURBANCE/OPEN WAVE TO BE LIFTED NORTHWARD ACROSS THE PLAINS AS A LARGE AREA OF LOW PRESSURE CIRCULATES ACROSS THE WESTERN STATES. WHILE SOUTHERLY RETURN FLOW WILL HELP DEWPOINTS CLIMB BACK TO NEAR 50 BY WEDNESDAY AFTERNOON...INSTABILITY WILL STILL BE VERY MARGINAL...SO OPTED TO ONLY MENTION AN ISOLATED THUNDERSTORM WEDNESDAY/WEDNESDAY NIGHT...WITH THE FOCUS OF THIS ACTIVITY SHIFTING SLIGHTLY EASTWARD FROM PREVIOUS FORECASTS AS THE LLJ IS FORECAST TO BE FOCUSED JUST EAST OF THE LOCAL AREA. WHILE INSTABILITY VALUES WILL BE A LITTLE MORE RESPECTABLE ON THURSDAY AFTERNOON...THE LACK OF ANY SIGNIFICANT FORCING MECHANISM SHOULD HELP LIMIT ANY DEVELOPMENT TO PRIMARILY THE DAYTIME HOURS... DEPENDING ON THE TIMING OF THE AFOREMENTIONED DISTURBANCE...WITH DRY WEATHER ANTICIPATED THURSDAY NIGHT INTO FRIDAY MORNING. THEREAFTER...INSTABILITY WILL INCREASE SIGNIFICANTLY ACROSS THE LOCAL AREA WITH MULTIPLE DISTURBANCES PASSING OUT OF THE LONGWAVE TROUGH. THIS SHOULD RESULT IN MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE LOCAL AREA FOR THE END OF THE WEEK AND START OF THE UPCOMING WEEKEND. IN ADDITION...WITH A MODEST LLJ EXPECTED TO DEVELOP EACH NIGHT...INCREASING SHEAR VALUES...AND MULTIPLE PASSING UPPER LEVEL DISTURBANCES...EXPECT THE POTENTIAL FOR SOME SEVERE WEATHER TO RETURN ON FRIDAY AND SATURDAY...WITH THE LOCAL AREA NOW HIGHLIGHTED FOR A CHANCE OF SEVERE WEATHER BY SPC IN THEIR DAY 5 AND DAY 6 FORECASTS. COULD SEE A BREAK IN SHOWER AND THUNDERSTORM ACTIVITY LATE IN THE UPCOMING WEEKEND AND EARLY NEXT WEEK AS A SHORTWAVE TROUGH TRANSITIONS ACROSS THE PLAINS...BUT MODELS ARE HINTING AT YET ANOTHER UPPER LEVEL LOW EMERGING FROM THE SOUTHWEST EARLY NEXT WEEK WHICH COULD AFFECT THE LOCAL AREA JUST BEYOND THE CURRENT SCOPE OF THE EXTENDED FORECAST. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z TUE NIGHT) ISSUED AT 1242 AM CDT TUE MAY 12 2015 REST OF TONIGHT: VFR SKC. LIGHT W WINDS WILL BECOME LGT AND VRBL. CONFIDENCE: HIGH TUE: VFR WITH A PERIOD OF PATCHY OF 7K FT SCT CLOUDS. WINDS BECOME S AND WILL GUST 20-27 KTS WITH POTENTIAL FOR 32 KTS. CONFIDENCE: HIGH TUE EVE: VFR. S WINDS BECOME SSE AND WILL CONT TO GUST UP TO 25 KTS AT TIMES. HAVE INCLUDED LLWS TO COVER PERIODIC LULLS IN SFC WINDS. CONFIDENCE: HIGH && .GID WATCHES/WARNINGS/ADVISORIES... NE...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039-040-046- 047-060>062-072>075-082>085. KS...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ005>007- 017>019. && $$ UPDATE...HALBLAUB SHORT TERM...HALBLAUB LONG TERM...ROSSI AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
646 PM EDT TUE MAY 12 2015 .SYNOPSIS... SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED LATE TODAY AHEAD OF A COLD FRONT TONIGHT. LESS HUMID AIR WILL ARRIVE WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 620 PM TUESDAY...SOME RE-ADJUSTMENTS OF THIS EVENING AND OVERNIGHT POPS BASED ON LATEST TSTORM ACTIVITY BREAKING OUT ACROSS THE EXTREME WESTERN PORTIONS OF THE ILM CWA AHEAD OF THE APPROACHING COLD FRONT. IF THE ACTIVITY HOLDS TOGETHER AS IT PUSHES EASTWARD...AND MEETS UP WITH THE SEA BREEZE...FURTHER ACTIVITY COULD BLOSSOM. ALTHOUGH AT THIS TIME VIA KLTX 88D AND VIS SAT IMAGERY...IT LOOKS LIKE THE SEA BREEZE HAS REACHED ITS MAXIMUM PUSH INLAND. STILL...ENOUGH SFC FORCING SHOULD AID CONTINUING THE CONVECTION AS IT PUSHES EASTWARD BEFORE THE MARINE INFLUENCES BEHIND THE SEA BREEZE LIKELY PARTIALLY OR ENTIRELY EXTINGUISHES IT. OVERALL...KEPT POPS IN THE LOWER CHANCE CATEGORY. CURRENT MIN TEMP FORECAST LOOKS AOK...NO CHANGES NEEDED AT THIS TIME. PREVIOUS...................................................... AS OF 318 PM TUESDAY...VERY HOT DAY ONGOING ACROSS THE CWA WITH LOTS OF 90-91 READINGS AND MID 60S TO AROUND 70 DEWPOINTS. THE SEA BREEZE IS CLEARLY EVIDENT AS A LINE OF MODERATE CU FROM ABOUT BURGAW TO TABOR CITY TO GEORGETOWN...MAKING MUCH MORE PROGRESS NW INTO NC ON THE RESULTANT. THIS WILL CONTINUE TO SLOWLY PUSH WEST THIS AFTN...BUT BASED OFF THE STRUGGLE OF THE CU TO GAIN VERTICAL DEPTH...HAVE CUT BACK POP TO JUST A VERY ISOLATED SHOWER ALONG THE SEA BREEZE. PRE-FRONTAL TROUGH WILL APPROACH THIS EVENING AND IS LIKELY TO BE OUR ONLY CHANCE FOR TSTMS TODAY. HRRR IS ALL OF A SUDDEN VERY AGGRESSIVE WITH CONVECTION ALONG IT THIS EVENING AND RACING EAST OFFSHORE EARLY IN THE NIGHTTIME PERIOD. WHILE THIS TIMING IS APPROPRIATE...HAVE A HARD TIME PLACING MORE THAN 40 POP ANYWHERE FOR ISOLATED TO SCATTERED TSTMS...MORE LIKE THE WRF SOLUTION. THINK THE MID-LEVELS ARE JUST A BIT TOO WARM FOR STRONG CONVECTION...BUT THE SPC SWODY1 MAINTAINS A MRGL RISK FOR OUR NC ZONES AND CANNOT RULE OUT AN ISOLATED WIND GUST AS INVERTED-V SOUNDINGS ARE FORECAST AHEAD OF THIS TROUGH. PRE-FRONTAL TROUGH WILL MOVE OFFSHORE...AND THEN SUBSEQUENT COLD FRONT WILL THEN TRAVERSE THE CWA LATE TONIGHT...MOVING OFFSHORE BY DAWN WEDNESDAY. NO CONVECTION EXPECTED ALONG THE BOUNDARY...BUT A SIGNIFICANT AIR MASS CHANGE WITH QUICKLY COOLING TEMPS AND MUCH DRIER DEWPOINTS WILL OCCUR. LOWS TONIGHT WILL RANGE FROM AROUND 60 WELL INLAND...TO ABOUT 65 AT THE COAST. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 318 PM TUESDAY...CHANGING OF THE GUARD SO TO SPEAK IN TERMS OF AIR MASS REPLACEMENT THIS PERIOD...AS A COLD FRONT MIGRATES OFF THE COAST AROUND DAYBREAK WEDNESDAY. POST FRONTAL N WIND WILL TEND TO NE WEDNESDAY ACCOMPANIED BY LOWERING DEWPOINTS IN THE 50S MAKING FOR CONSIDERABLY LESS MUGGINESS...WITH MAXIMUMS OF UPPER 70S TO LOWER 80S WITH SUN. EARLY THURSDAY SEASONABLY COOL MINIMUMS OF UPPER 50S TO LOWER 60S...MILDEST COAST. A COOLER DAY SETTING UP THURSDAY AS HIGH PRESSURE FROM THE GREAT LAKES DROPS SOUTHEAST TOWARD THE CAROLINAS...SUPPLYING A DOSE OF COOL AIR ADVECTION. MINIMUMS EARLY FRIDAY SIMILAR TO THURSDAY UPPER 50S TO LOWER 60S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 318 PM TUESDAY...TRANSITION PERIOD AS HIGH PRESSURE MOVES OFFSHORE FRIDAY AND RETURN FLOW RESUMES ACROSS THE AREA. THIS WILL BRING A TREND UPWARD IN TEMPERATURES AND HUMIDITY WITH AN INCREASING CHANCE OF SHOWERS/TSTMS AS A COLD FRONT GRADUALLY APPROACHES FROM THE WEST THIS WEEKEND. THE FRONT MAY STALL OVER THE AREA EARLY NEXT WEEK...OFFERING HIGH HUMIDITY AND EVEN A BETTER CHANCE OF PCPN INTO EARLY NEXT WEEK. THIS REGIME SHOULD RESULT IN TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATE STANDARDS FOR MIDDLE MAY. && .AVIATION /00Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...SOME ISOLATED CONVECTION IS TRYING TO FORM AHEAD OF A COLD FRONT THAT WILL SWING THROUGH THE REGION OVERNIGHT. SINCE WE ARE LOSING OUR AFTERNOON HEATING...DO NOT THINK THE CONVECTION WILL GET BETTER ORGANIZED BUT THERE COULD BE A BRIEF BUMP UP AS THE CONVECTION ENCOUNTERS THE SEA BREEZE BOUNDARY IN A COUPLE OF HOURS. OVERNIGHT...LOOK FOR ANY LEFTOVER CONVECTION TO REACH THE COAST BY 05Z. WINDS WILL SHIFT TO THE NORTH BEHIND THE COLD FRONT AFTER MIDNIGHT...WITH MODERATE NORTHEAST FLOW EXPECTED FOR WEDNESDAY WITH LESS HUMID CONDITIONS. EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 PM TUESDAY...SSW-SW WINDS 15 TO 20 KT TO PREVAIL WELL INTO TONIGHT...DIMINISHING TO 10-15 KT AS THE COLD FRONT APPROACHES...AND LIKELY VEERING TO THE NW-N AROUND 15 KT BY DAYBREAK WED AFTER FROPA. SIGNIFICANT SEAS WILL RUN 2 TO 4 FT...HIEST ACROSS THE WATERS FROM CAPE FEAR SOUTH TO LITTLE RIVER INLET WHERE THE FETCH IS GREATEST GIVEN THE WIND DIRECTION. A 1 TO 2 FOOT 7-8 SECOND PERIOD GROUND SWELL REMAINS IDENTIFIABLE...BUT WIND DRIVEN WAVES AT 4 TO 5 SECONDS WILL DOMINATE THE SIGNIFICANT SEAS. PREVIOUS..................................................... AS OF 318 PM TUESDAY...HIGH PRESSURE OFFSHORE CONTINUES TO DRIVE SW WINDS ACROSS THE WATERS THIS AFTN. SPEEDS ARE GENERALLY AROUND 15 KTS...BUT ARE REACHING 20 KTS WITH SOME BACKING TO THE SOUTH NEAR THE COAST THANKS TO THE LOCAL SEA BREEZE ENHANCEMENT. THE SEA BREEZE WILL EASE WITH LOSS OF HEATING...LEAVING 15 KT WINDS ACROSS THE WATERS TONIGHT...ALONG WITH PERSISTENT 2-4 FT SEAS. THE WAVE PERIOD WILL BE AROUND 7 SEC...SHORTER IN THE MORE WIND-DRIVEN SEA BREEZE NEAR SHORE. A COLD FRONT WILL CROSS THE WATERS TOWARDS DAWN ON WEDNESDAY...TURNING THE WINDS QUICKLY TO THE N/NW AND DRIVING THE HIGHER WAVES AWAY FROM SHORE. A FEW SHOWERS AND TSTMS MAY ACCOMPANY THIS FRONT...BUT WIDESPREAD CONVECTION IS NOT CURRENTLY ANTICIPATED. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 318 PM TUESDAY...A COLD FRONTAL PASSAGE TO BRING A WINDSHIFT TO NORTH ON THE WATERS WEDNESDAY...TENDING TO NE AND ENE HEADING INTO LATER WEDNESDAY AND THURSDAY. NO ADVISORIES BUT NE GUSTS TO 20 KT EXPECTED EARLY THURSDAY AS HIGH PRESSURE BUILDS FROM THE NW. SEAS 2-3 FEET WEDNESDAY WILL BUILD TO 3-4 FEET THURSDAY. NO TSTMS OR VISIBILITY RESTRICTIONS ON THE 0-20 NM WATERS EXPECTED WED/THU/ .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 318 PM TUESDAY...A TRANSITION TO A BERMUDA HIGH PRESSURE PATTERN AS HIGH PRESSURE MOVES OFFSHORE AND RETURN SW WINDS PREVAIL BEGINNING FRIDAY AND PERSISTING THROUGH THE WEEKEND. WARMING DAYTIME TEMPERATURES WILL DRIVE A SEA BREEZE AND AFTERNOON GUSTS TO 20 KT SHOULD BE EXPECTED NEAR SHORE OVER THE WEEKEND. ISOLATED SHOWERS AND TSTMS SHOULD ALSO BE EXPECTED INTO THE WEEKEND AS S AND SW WINDS INTRODUCE ADDITIONAL MOISTURE INTO THE REGION. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MJC NEAR TERM...DCH/JDW SHORT TERM...MJC LONG TERM...SHK AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
642 PM EDT TUE MAY 12 2015 .SYNOPSIS... SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED LATE TODAY AHEAD OF A COLD FRONT TONIGHT. LESS HUMID AIR WILL ARRIVE WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 620 PM TUESDAY...SOME RE-ADJUSTMENTS OF THIS EVENING AND OVERNIGHT POPS BASED ON LATEST TSTORM ACTIVITY BREAKING OUT ACROSS THE EXTREME WESTERN PORTIONS OF THE ILM CWA AHEAD OF THE APPROACHING COLD FRONT. IF THE ACTIVITY HOLDS TOGETHER AS IT PUSHES EASTWARD...AND MEETS UP WITH THE SEA BREEZE...FURTHER ACTIVITY COULD BLOSSOM. ALTHOUGH AT THIS TIME VIA KLTX 88D AND VIS SAT IMAGERY...IT LOOKS LIKE THE SEA BREEZE HAS REACHED ITS MAXIMUM PUSH INLAND. STILL...ENOUGH SFC FORCING SHOULD AID CONTINUING THE CONVECTION AS IT PUSHES EASTWARD BEFORE THE MARINE INFLUENCES BEHIND THE SEA BREEZE LIKELY PARTIALLY OR ENTIRELY EXTINGUISHES IT. OVERALL...KEPT POPS IN THE LOWER CHANCE CATEGORY. CURRENT MIN TEMP FORECAST LOOKS AOK...NO CHANGES NEEDED AT THIS TIME. PREVIOUS...................................................... AS OF 318 PM TUESDAY...VERY HOT DAY ONGOING ACROSS THE CWA WITH LOTS OF 90-91 READINGS AND MID 60S TO AROUND 70 DEWPOINTS. THE SEA BREEZE IS CLEARLY EVIDENT AS A LINE OF MODERATE CU FROM ABOUT BURGAW TO TABOR CITY TO GEORGETOWN...MAKING MUCH MORE PROGRESS NW INTO NC ON THE RESULTANT. THIS WILL CONTINUE TO SLOWLY PUSH WEST THIS AFTN...BUT BASED OFF THE STRUGGLE OF THE CU TO GAIN VERTICAL DEPTH...HAVE CUT BACK POP TO JUST A VERY ISOLATED SHOWER ALONG THE SEA BREEZE. PRE-FRONTAL TROUGH WILL APPROACH THIS EVENING AND IS LIKELY TO BE OUR ONLY CHANCE FOR TSTMS TODAY. HRRR IS ALL OF A SUDDEN VERY AGGRESSIVE WITH CONVECTION ALONG IT THIS EVENING AND RACING EAST OFFSHORE EARLY IN THE NIGHTTIME PERIOD. WHILE THIS TIMING IS APPROPRIATE...HAVE A HARD TIME PLACING MORE THAN 40 POP ANYWHERE FOR ISOLATED TO SCATTERED TSTMS...MORE LIKE THE WRF SOLUTION. THINK THE MID-LEVELS ARE JUST A BIT TOO WARM FOR STRONG CONVECTION...BUT THE SPC SWODY1 MAINTAINS A MRGL RISK FOR OUR NC ZONES AND CANNOT RULE OUT AN ISOLATED WIND GUST AS INVERTED-V SOUNDINGS ARE FORECAST AHEAD OF THIS TROUGH. PRE-FRONTAL TROUGH WILL MOVE OFFSHORE...AND THEN SUBSEQUENT COLD FRONT WILL THEN TRAVERSE THE CWA LATE TONIGHT...MOVING OFFSHORE BY DAWN WEDNESDAY. NO CONVECTION EXPECTED ALONG THE BOUNDARY...BUT A SIGNIFICANT AIR MASS CHANGE WITH QUICKLY COOLING TEMPS AND MUCH DRIER DEWPOINTS WILL OCCUR. LOWS TONIGHT WILL RANGE FROM AROUND 60 WELL INLAND...TO ABOUT 65 AT THE COAST. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 318 PM TUESDAY...CHANGING OF THE GUARD SO TO SPEAK IN TERMS OF AIR MASS REPLACEMENT THIS PERIOD...AS A COLD FRONT MIGRATES OFF THE COAST AROUND DAYBREAK WEDNESDAY. POST FRONTAL N WIND WILL TEND TO NE WEDNESDAY ACCOMPANIED BY LOWERING DEWPOINTS IN THE 50S MAKING FOR CONSIDERABLY LESS MUGGINESS...WITH MAXIMUMS OF UPPER 70S TO LOWER 80S WITH SUN. EARLY THURSDAY SEASONABLY COOL MINIMUMS OF UPPER 50S TO LOWER 60S...MILDEST COAST. A COOLER DAY SETTING UP THURSDAY AS HIGH PRESSURE FROM THE GREAT LAKES DROPS SOUTHEAST TOWARD THE CAROLINAS...SUPPLYING A DOSE OF COOL AIR ADVECTION. MINIMUMS EARLY FRIDAY SIMILAR TO THURSDAY UPPER 50S TO LOWER 60S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 318 PM TUESDAY...TRANSITION PERIOD AS HIGH PRESSURE MOVES OFFSHORE FRIDAY AND RETURN FLOW RESUMES ACROSS THE AREA. THIS WILL BRING A TREND UPWARD IN TEMPERATURES AND HUMIDITY WITH AN INCREASING CHANCE OF SHOWERS/TSTMS AS A COLD FRONT GRADUALLY APPROACHES FROM THE WEST THIS WEEKEND. THE FRONT MAY STALL OVER THE AREA EARLY NEXT WEEK...OFFERING HIGH HUMIDITY AND EVEN A BETTER CHANCE OF PCPN INTO EARLY NEXT WEEK. THIS REGIME SHOULD RESULT IN TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATE STANDARDS FOR MIDDLE MAY. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... AS OF 18Z...THE SEA BREEZE HAS DEVELOPED WITH PRETTY MUCH A STEADY S-SSW WIND AROUND 13KT AT THE COASTAL TERMINALS. WINDS AT KFLO/KLBT ARE SW 8-12KT. TERMINALS ARE VFR...AND THE IFR CIGS JUST NORTH OF CRE SHOULD REMAIN JUST AWAY FROM THE TERMINAL. CONFIDENCE IS MODERATE TO HIGH KCRE WILL REMAIN VFR. A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF PERIOD. IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO DEVELOP THIS EVENING. APPEARS THE BEST AREA FOR DEVELOPMENT WILL BE BETWEEN THE INLAND AND COASTAL TERMINALS WHERE SURFACE WINDS ARE CONVERGING...AND LATEST HIGH RES GUIDANCE SUGGESTS THIS WILL NOT EVEN REACH THE COASTAL TERMINALS AS IT STABILIZES BEHIND THE SEA BREEZE. CONVECTION SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT WILL MOVE THROUGH DURING OVERNIGHT HOURS. PRECIPITATION WILL DROP AFTER THE FRONT MOVES THROUGH. VFR WILL CONTINUE INTO THE MORNING HOURS WITH VFR/NE WINDS AFTER SUNRISE. EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 PM TUESDAY...SSW-SW WINDS 15 TO 20 KT TO PREVAIL WELL INTO TONIGHT...DIMINISHING TO 10-15 KT AS THE COLD FRONT APPROACHES...AND LIKELY VEERING TO THE NW-N AROUND 15 KT BY DAYBREAK WED AFTER FROPA. SIGNIFICANT SEAS WILL RUN 2 TO 4 FT...HIEST ACROSS THE WATERS FROM CAPE FEAR SOUTH TO LITTLE RIVER INLET WHERE THE FETCH IS GREATEST GIVEN THE WIND DIRECTION. A 1 TO 2 FOOT 7-8 SECOND PERIOD GROUND SWELL REMAINS IDENTIFIABLE...BUT WIND DRIVEN WAVES AT 4 TO 5 SECONDS WILL DOMINATE THE SIGNIFICANT SEAS. PREVIOUS..................................................... AS OF 318 PM TUESDAY...HIGH PRESSURE OFFSHORE CONTINUES TO DRIVE SW WINDS ACROSS THE WATERS THIS AFTN. SPEEDS ARE GENERALLY AROUND 15 KTS...BUT ARE REACHING 20 KTS WITH SOME BACKING TO THE SOUTH NEAR THE COAST THANKS TO THE LOCAL SEA BREEZE ENHANCEMENT. THE SEA BREEZE WILL EASE WITH LOSS OF HEATING...LEAVING 15 KT WINDS ACROSS THE WATERS TONIGHT...ALONG WITH PERSISTENT 2-4 FT SEAS. THE WAVE PERIOD WILL BE AROUND 7 SEC...SHORTER IN THE MORE WIND-DRIVEN SEA BREEZE NEAR SHORE. A COLD FRONT WILL CROSS THE WATERS TOWARDS DAWN ON WEDNESDAY...TURNING THE WINDS QUICKLY TO THE N/NW AND DRIVING THE HIGHER WAVES AWAY FROM SHORE. A FEW SHOWERS AND TSTMS MAY ACCOMPANY THIS FRONT...BUT WIDESPREAD CONVECTION IS NOT CURRENTLY ANTICIPATED. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 318 PM TUESDAY...A COLD FRONTAL PASSAGE TO BRING A WINDSHIFT TO NORTH ON THE WATERS WEDNESDAY...TENDING TO NE AND ENE HEADING INTO LATER WEDNESDAY AND THURSDAY. NO ADVISORIES BUT NE GUSTS TO 20 KT EXPECTED EARLY THURSDAY AS HIGH PRESSURE BUILDS FROM THE NW. SEAS 2-3 FEET WEDNESDAY WILL BUILD TO 3-4 FEET THURSDAY. NO TSTMS OR VISIBILITY RESTRICTIONS ON THE 0-20 NM WATERS EXPECTED WED/THU/ .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 318 PM TUESDAY...A TRANSITION TO A BERMUDA HIGH PRESSURE PATTERN AS HIGH PRESSURE MOVES OFFSHORE AND RETURN SW WINDS PREVAIL BEGINNING FRIDAY AND PERSISTING THROUGH THE WEEKEND. WARMING DAYTIME TEMPERATURES WILL DRIVE A SEA BREEZE AND AFTERNOON GUSTS TO 20 KT SHOULD BE EXPECTED NEAR SHORE OVER THE WEEKEND. ISOLATED SHOWERS AND TSTMS SHOULD ALSO BE EXPECTED INTO THE WEEKEND AS S AND SW WINDS INTRODUCE ADDITIONAL MOISTURE INTO THE REGION. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MJC NEAR TERM...DCH/JDW SHORT TERM...MJC LONG TERM...SHK AVIATION...DL
AREA FORECAST DISCUSSION...COR
NWS WILMINGTON NC
318 PM EDT TUE MAY 12 2015 .SYNOPSIS... SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED LATE TODAY AHEAD OF A COLD FRONT TONIGHT. LESS HUMID AIR WILL ARRIVE WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 318 PM TUESDAY...VERY HOT DAY ONGOING ACROSS THE CWA WITH LOTS OF 90-91 READINGS AND MID 60S TO AROUND 70 DEWPOINTS. THE SEA BREEZE IS CLEARLY EVIDENT AS A LINE OF MODERATE CU FROM ABOUT BURGAW TO TABOR CITY TO GEORGETOWN...MAKING MUCH MORE PROGRESS NW INTO NC ON THE RESULTANT. THIS WILL CONTINUE TO SLOWLY PUSH WEST THIS AFTN...BUT BASED OFF THE STRUGGLE OF THE CU TO GAIN VERTICAL DEPTH...HAVE CUT BACK POP TO JUST A VERY ISOLATED SHOWER ALONG THE SEA BREEZE. PRE-FRONTAL TROUGH WILL APPROACH THIS EVENING AND IS LIKELY TO BE OUR ONLY CHANCE FOR TSTMS TODAY. HRRR IS ALL OF A SUDDEN VERY AGGRESSIVE WITH CONVECTION ALONG IT THIS EVENING AND RACING EAST OFFSHORE EARLY IN THE NIGHTTIME PERIOD. WHILE THIS TIMING IS APPROPRIATE...HAVE A HARD TIME PLACING MORE THAN 40 POP ANYWHERE FOR ISOLATED TO SCATTERED TSTMS...MORE LIKE THE WRF SOLUTION. THINK THE MID-LEVELS ARE JUST A BIT TOO WARM FOR STRONG CONVECTION...BUT THE SPC SWODY1 MAINTAINS A MRGL RISK FOR OUR NC ZONES AND CANNOT RULE OUT AN ISOLATED WIND GUST AS INVERTED-V SOUNDINGS ARE FORECAST AHEAD OF THIS TROUGH. PRE-FRONTAL TROUGH WILL MOVE OFFSHORE...AND THEN SUBSEQUENT COLD FRONT WILL THEN TRAVERSE THE CWA LATE TONIGHT...MOVING OFFSHORE BY DAWN WEDNESDAY. NO CONVECTION EXPECTED ALONG THE BOUNDARY...BUT A SIGNIFICANT AIR MASS CHANGE WITH QUICKLY COOLING TEMPS AND MUCH DRIER DEWPOINTS WILL OCCUR. LOWS TONIGHT WILL RANGE FROM AROUND 60 WELL INLAND...TO ABOUT 65 AT THE COAST. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 318 PM TUESDAY...CHANGING OF THE GUARD SO TO SPEAK IN TERMS OF AIR MASS REPLACEMENT THIS PERIOD...AS A COLD FRONT MIGRATES OFF THE COAST AROUND DAYBREAK WEDNESDAY. POST FRONTAL N WIND WILL TEND TO NE WEDNESDAY ACCOMPANIED BY LOWERING DEWPOINTS IN THE 50S MAKING FOR CONSIDERABLY LESS MUGGINESS...WITH MAXIMUMS OF UPPER 70S TO LOWER 80S WITH SUN. EARLY THURSDAY SEASONABLY COOL MINIMUMS OF UPPER 50S TO LOWER 60S...MILDEST COAST. A COOLER DAY SETTING UP THURSDAY AS HIGH PRESSURE FROM THE GREAT LAKES DROPS SOUTHEAST TOWARD THE CAROLINAS...SUPPLYING A DOSE OF COOL AIR ADVECTION. MINIMUMS EARLY FRIDAY SIMILAR TO THURSDAY UPPER 50S TO LOWER 60S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 318 PM TUESDAY...TRANSITION PERIOD AS HIGH PRESSURE MOVES OFFSHORE FRIDAY AND RETURN FLOW RESUMES ACROSS THE AREA. THIS WILL BRING A TREND UPWARD IN TEMPERATURES AND HUMIDITY WITH AN INCREASING CHANCE OF SHOWERS/TSTMS AS A COLD FRONT GRADUALLY APPROACHES FROM THE WEST THIS WEEKEND. THE FRONT MAY STALL OVER THE AREA EARLY NEXT WEEK...OFFERING HIGH HUMIDITY AND EVEN A BETTER CHANCE OF PCPN INTO EARLY NEXT WEEK. THIS REGIME SHOULD RESULT IN TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATE STANDARDS FOR MIDDLE MAY. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... AS OF 18Z...THE SEA BREEZE HAS DEVELOPED WITH PRETTY MUCH A STEADY S-SSW WIND AROUND 13KT AT THE COASTAL TERMINALS. WINDS AT KFLO/KLBT ARE SW 8-12KT. TERMINALS ARE VFR...AND THE IFR CIGS JUST NORTH OF CRE SHOULD REMAIN JUST AWAY FROM THE TERMINAL. CONFIDENCE IS MODERATE TO HIGH KCRE WILL REMAIN VFR. A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF PERIOD. IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO DEVELOP THIS EVENING. APPEARS THE BEST AREA FOR DEVELOPMENT WILL BE BETWEEN THE INLAND AND COASTAL TERMINALS WHERE SURFACE WINDS ARE CONVERGING...AND LATEST HIGH RES GUIDANCE SUGGESTS THIS WILL NOT EVEN REACH THE COASTAL TERMINALS AS IT STABILIZES BEHIND THE SEA BREEZE. CONVECTION SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT WILL MOVE THROUGH DURING OVERNIGHT HOURS. PRECIPITATION WILL DROP AFTER THE FRONT MOVES THROUGH. VFR WILL CONTINUE INTO THE MORNING HOURS WITH VFR/NE WINDS AFTER SUNRISE. EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 318 PM TUESDAY...HIGH PRESSURE OFFSHORE CONTINUES TO DRIVE SW WINDS ACROSS THE WATERS THIS AFTN. SPEEDS ARE GENERALLY AROUND 15 KTS...BUT ARE REACHING 20 KTS WITH SOME BACKING TO THE SOUTH NEAR THE COAST THANKS TO THE LOCAL SEA BREEZE ENHANCEMENT. THE SEA BREEZE WILL EASE WITH LOSS OF HEATING...LEAVING 15 KT WINDS ACROSS THE WATERS TONIGHT...ALONG WITH PERSISTENT 2-4 FT SEAS. THE WAVE PERIOD WILL BE AROUND 7 SEC...SHORTER IN THE MORE WIND-DRIVEN SEA BREEZE NEAR SHORE. A COLD FRONT WILL CROSS THE WATERS TOWARDS DAWN ON WEDNESDAY...TURNING THE WINDS QUICKLY TO THE N/NW AND DRIVING THE HIGHER WAVES AWAY FROM SHORE. A FEW SHOWERS AND TSTMS MAY ACCOMPANY THIS FRONT...BUT WIDESPREAD CONVECTION IS NOT CURRENTLY ANTICIPATED. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 318 PM TUESDAY...A COLD FRONTAL PASSAGE TO BRING A WINDSHIFT TO NORTH ON THE WATERS WEDNESDAY...TENDING TO NE AND ENE HEADING INTO LATER WEDNESDAY AND THURSDAY. NO ADVISORIES BUT NE GUSTS TO 20 KT EXPECTED EARLY THURSDAY AS HIGH PRESSURE BUILDS FROM THE NW. SEAS 2-3 FEET WEDNESDAY WILL BUILD TO 3-4 FEET THURSDAY. NO TSTMS OR VISIBILITY RESTRICTIONS ON THE 0-20 NM WATERS EXPECTED WED/THU/ .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 318 PM TUESDAY...A TRANSITION TO A BERMUDA HIGH PRESSURE PATTERN AS HIGH PRESSURE MOVES OFFSHORE AND RETURN SW WINDS PREVAIL BEGINNING FRIDAY AND PERSISTING THROUGH THE WEEKEND. WARMING DAYTIME TEMPERATURES WILL DRIVE A SEA BREEZE AND AFTERNOON GUSTS TO 20 KT SHOULD BE EXPECTED NEAR SHORE OVER THE WEEKEND. ISOLATED SHOWERS AND TSTMS SHOULD ALSO BE EXPECTED INTO THE WEEKEND AS S AND SW WINDS INTRODUCE ADDITIONAL MOISTURE INTO THE REGION. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...MJC LONG TERM...MJC AVIATION...MRR/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
124 PM EDT TUE MAY 12 2015 .SYNOPSIS... SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AHEAD OF A COLD FRONT. LESS HUMID AIR ARRIVES ON WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM TUESDAY...HOT AND HUMID DAY ONGOING ACROSS THE CWA EVEN AT THIS EARLY HOUR. AFTER STARTING FROM LOWS AROUND 70...TEMPS ARE SHOOTING UP QUICKLY THIS MORNING THANKS TO 950MB TEMPS CLOSE TO 22C ON THE 8AM KCHS U/A SOUNDING. HIGH PRESSURE CENTERED WELL OFFSHORE IS PUMPING RETURN FLOW INTO THE CAROLINAS...WHICH IS STRENGTHENING WARM ADVECTION IN A PRE-FRONTAL AIRMASS. THE COMBINATION OF THIS HEAT AND DEWPOINT TEMPS AROUND 70 WILL DRIVE HEAT INDICES INTO THE MID 90S AWAY FROM THE COAST TODAY...THE MOST UNCOMFORTABLE DAY OF 2015 SO FAR. THIS HUMID AIR MASS WILL DRIVE INSTABILITY THIS AFTN...AND CONVECTION IS ONCE AGAIN EXPECTED ACROSS THE AREA. VERY STEEP LR`S UP TO 800MB WILL DRIVE RAPID UPDRAFTS...AND SBCAPE IS FORECAST TO RISE TO AROUND 3000 J/KG...POSSIBLY HIGHER RIGHT ALONG THE SEA BREEZE. THIS WILL SERVE AS THE FUEL FOR STORMS TODAY...WHICH SHOULD DEVELOP ALONG THE SEA BREEZE...AND THEN LATER ALONG A PRE-FRONTAL TROUGH APPROACHING FROM THE WEST. WHILE RESIDUAL BOUNDARIES MAY FIRE WEAK STORMS...MID LEVEL TEMPS ARE NOT EXCEEDINGLY COOL (-8C AT 500MB) SO WIDESPREAD STRONG UPDRAFTS ARE NOT ANTICIPATED. STILL...ENOUGH FORCING WILL DRIVE PARCELS UP INTO DECENT HAIL-ZONE INSTABILITY...AND AN INVERTED-V TYPE SIGNATURE IS PROGGED WELL INLAND AHEAD OF THE PRE-FRONTAL TROUGH. BULK-SHEAR VALUES STRUGGLE TO AROUND 20 KTS...SO WIDESPREAD STORM ORGANIZATION IS UNLIKELY...BUT PULSE STORMS AND AT LEAST SOME LINEAR FEATURES ALONG THE PRE-FRONTAL TROUGH WILL HAVE THE POTENTIAL TO PRODUCE AN ISOLATED WIND GUST OR LARGE HAIL STONE THIS AFTN. HIGH-RES HRRR AND NSSL WRF SUGGEST ONLY ISOLATED STORMS UNTIL THE PRE-FRONTAL TROUGH THIS EVENING...WHICH WILL BE THE PRIMARY DRIVER OF CONVECTION TODAY. BY THIS EVENING HOWEVER...WE BEGIN TO LOSE HEATING...AND HAVE CAPPED POP IN THE HIGH CHC RANGE. HIGHEST PROBABILITY FOR STORMS LOOKS TO BE ACROSS THE MIDDLE-PART OF THE CWA WHERE THE WESTWARD ADVANCING SEA BREEZE WILL INTERACT WITH THE EASTWARD MOVING TROUGH. CONVECTION WILL WANE AFTER DARK...AND LITTLE FANFARE IS EXPECTED WITH THE ACTUAL FROPA TONIGHT. HOWEVER...A SIGNIFICANT AIRMASS CHANGE WILL ACCOMPANY THIS FRONT...WITH MUCH DRIER AIR AND LOWS DROPPING INTO THE MID 60S AT THE COAST...AROUND 60 WELL INLAND. ALSO NEED TO NOTE A PERSISTENT AREA OF SEA-STRATUS FROM ABOUT NORTH MYRTLE BEACH TO BALD HEAD ISLAND. SHELF WATERS MUST BE JUST COOL ENOUGH TO TAP INTO THE IDEALIZED RESIDENCE PARCEL TIMES ENCOUNTERED BY THE W/SW WINDS IN ORDER TO SATURATE IN THIS AREA. THE COMBINATION OF THE BACKING WINDS WITHIN THE SEA BREEZE...AS WELL AS SIGNIFICANT HEATING JUST INLAND...SHOULD BREAK APART THIS STRATUS BY EARLY AFTN...BUT IT IS UNLIKELY THE NEAR-COAST AREA HERE WILL EXPERIENCE THE HOT/HUMID/SUNNY DAY GOING ON ELSEWHERE ACROSS THE CWA. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY... SOME VERY PLEASANT WEATHER EXPECTED THROUGH THE PERIOD. HIGH PRESSURE WELL TO OUR NORTH WILL SHOW LITTLE MOVEMENT WEDNESDAY WHILE THE TUESDAY NIGHT COLD FRONT STALLS WELL TO OUR SOUTH. IN BETWEEN THE TWO WE WILL SEE A N TO NE FLOW LOCALLY THAT WILL BRING SOME MUCH LOWER DEWPOINTS. A MILD LEVEL RIDGE WILL BE JUST TO OUR WEST ALLOWING FOR DEEP LAYER DRY AIR AND AMPLE SUNSHINE. ON THURSDAY THE HIGH WILL MOVE CLOSER TO THE REGION KEEPING TEMPERATURES A BIT BELOW CLIMATOLOGY. A LITTLE MOISTURE RETURN MAY GET UNDERWAY THURSDAY NIGHT AS THE HIGH MOVES FURTHER TO THE EAST, MAINLY OVER WESTERN ZONE. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...RETURN FLOW ON FRIDAY AND SATURDAY AS HIGH PRESSURE SITES OFF THE COAST. THE MID LEVEL RIDGE WILL BE OVERHEAD HOWEVER PRECLUDING DEEP MOISTURE AND CONFINING IT TO THE LOWER LEVELS. SO WHILE A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED OUT ANY COVERAGE SHOULD BE MINIMAL. OVER THE WEEKEND AND EVEN INTO MONDAY FOR THAT MATTER THE MID LEVEL RIDGING APPEARS TO RESURGE. DESPITE THIS THE GFS AND ECMWF BOTH DEPICT AN INCREASE IN PRECIPITATION COVERAGE. WHILE THE CONTINUED MOISTENING OF THE LOW LEVELS DOES IN FACT ARGUE FOR THIS THE MID LEVEL DRYNESS PROBABLY MEANS THAT ITS RATHER SUBTLE. TEMPERATURES MEANWHILE WILL GROW WARMER EACH DAY AND NIGHT. && .AVIATION /18Z TUESDAY THROUGH SUNDAY /... AS OF 18Z...THE SEA BREEZE HAS DEVELOPED WITH PRETTY MUCH A STEADY S- SSW WIND AROUND 13KT AT THE COASTAL TERMINALS. WINDS AT KFLO/KLBT ARE SW 8-12KT. TERMINALS ARE VFR...AND THE IFR CIGS JUST NORTH OF CRE SHOULD REMAIN JUST AWAY FROM THE TERMINAL. CONFIDENCE IS MODERATE TO HIGH KCRE WILL REMAIN VFR. A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF PERIOD. IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO DEVELOP THIS EVENING. APPEARS THE BEST AREA FOR DEVELOPMENT WILL BE BETWEEN THE INLAND AND COASTAL TERMINALS WHERE SURFACE WINDS ARE CONVERGING...AND LATEST HIGH RES GUIDANCE SUGGESTS THIS WILL NOT EVEN REACH THE COASTAL TERMINALS AS IT STABILIZES BEHIND THE SEA BREEZE. CONVECTION SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT WILL MOVE THROUGH DURING OVERNIGHT HOURS. PRECIPITATION WILL DROP AFTER THE FRONT MOVES THROUGH. VFR WILL CONTINUE INTO THE MORNING HOURS WITH VFR/NE WINDS AFTER SUNRISE. EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM TUESDAY...HIGH PRESSURE OFFSHORE IS THE DOMINANT SYNOPTIC FEATURE ACROSS THE WATERS TODAY...DRIVING SW FLOW AND WINDS OF 10-15 KTS ACROSS THE WATERS. LOCAL ENHANCEMENTS OF UP TO 20 KTS...ALONG WITH A BACKING IN DIRECTION TO THE SOUTH...IS LIKELY ALONG THE SEA BREEZE THROUGH THE AFTN AS WELL. OTHER THAN SOME CHOPPY WATERS WITHIN THE NEAR SHORE WATERS THANKS TO THE SEA BREEZE...WAVE HEIGHTS ARE EXPECTED TO PERSIST AT 2-4 FT WITH A 6-7 SEC PERIOD DOMINANT. A COLD FRONT WILL CROSS THE WATERS LATE TONIGHT TURNING WINDS TO THE N/NW AT AROUND 15 KTS...AND PUSHING THE HIGHEST SEAS AWAY FROM THE COAST. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM TUESDAY... TUESDAY NIGHT`S FROPA WILL BRING A NORTHERLY FLOW ON WEDNESDAY. SURFACE HIGH REMAINS UP IN THE GREAT LAKES SO THE FLOW WILL BE QUITE LIGHT LOCALLY AND SEAS LIKELY JUST 2 TO 3 FT. JUST A SLIGHT VEER WEDNESDAY NIGHT WITH FLOW POSSIBLY GOING LIGHT AND VARIABLE FOR A TIME. THE HIGH EXTENDS JUST SLIGHTLY SOUTH ON THURSDAY WHILE PROGRESSING EAST. NE WINDS COULD INCREASE BY A CATEGORY AND BECOME A LITTLE GUSTY. THE COAST- PARALLEL FLOW WILL PRECLUDE MUCH BUILDING OF SEAS HOWEVER. .LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY... THE HIGH TO OUR NORTH PROGRESSES FURTHER EAST ON FRIDAY LEADING TO MORE VEERING LOCALLY. FRIDAY MAY SEE ONSHORE/EASTERLY FLOW MOST OF THE DAY WHILE A SOUTHERLY COMPONENT TRIES TO GET ESTABLISHED MAINLY OVER SOUTHERN ZONES. ON SATURDAY WE TRANSITION TO A FAIRLY NORMAL RETURN FLOW AROUND HIGH PRESSURE OFF THE EAST COAST. NOT A BERMUDA HIGH THOUGH WHICH TYPICALLY BRINGS SOUTHWESTERLY FLOW...THE WEEKEND WILL LIKELY SEE SOUTHEAST INSTEAD. THERE COULD BE A VERY GRADUAL INCREASE IN WAVE PERIOD AS A SWELL BECOMES ESTABLISHED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...JDW SHORT TERM...MBB LONG TERM...MBB AVIATION...MRR/JDW MARINE...JDW/MBB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1049 AM EDT TUE MAY 12 2015 .SYNOPSIS... SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AHEAD OF A COLD FRONT. LESS HUMID AIR ARRIVES ON WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM TUESDAY...HOT AND HUMID DAY ONGOING ACROSS THE CWA EVEN AT THIS EARLY HOUR. AFTER STARTING FROM LOWS AROUND 70...TEMPS ARE SHOOTING UP QUICKLY THIS MORNING THANKS TO 950MB TEMPS CLOSE TO 22C ON THE 8AM KCHS U/A SOUNDING. HIGH PRESSURE CENTERED WELL OFFSHORE IS PUMPING RETURN FLOW INTO THE CAROLINAS...WHICH IS STRENGTHENING WARM ADVECTION IN A PRE-FRONTAL AIRMASS. THE COMBINATION OF THIS HEAT AND DEWPOINT TEMPS AROUND 70 WILL DRIVE HEAT INDICES INTO THE MID 90S AWAY FROM THE COAST TODAY...THE MOST UNCOMFORTABLE DAY OF 2015 SO FAR. THIS HUMID AIR MASS WILL DRIVE INSTABILITY THIS AFTN...AND CONVECTION IS ONCE AGAIN EXPECTED ACROSS THE AREA. VERY STEEP LR`S UP TO 800MB WILL DRIVE RAPID UPDRAFTS...AND SBCAPE IS FORECAST TO RISE TO AROUND 3000 J/KG...POSSIBLY HIGHER RIGHT ALONG THE SEA BREEZE. THIS WILL SERVE AS THE FUEL FOR STORMS TODAY...WHICH SHOULD DEVELOP ALONG THE SEA BREEZE...AND THEN LATER ALONG A PRE-FRONTAL TROUGH APPROACHING FROM THE WEST. WHILE RESIDUAL BOUNDARIES MAY FIRE WEAK STORMS...MID LEVEL TEMPS ARE NOT EXCEEDINGLY COOL (-8C AT 500MB) SO WIDESPREAD STRONG UPDRAFTS ARE NOT ANTICIPATED. STILL...ENOUGH FORCING WILL DRIVE PARCELS UP INTO DECENT HAIL-ZONE INSTABILITY...AND AN INVERTED-V TYPE SIGNATURE IS PROGGED WELL INLAND AHEAD OF THE PRE-FRONTAL TROUGH. BULK-SHEAR VALUES STRUGGLE TO AROUND 20 KTS...SO WIDESPREAD STORM ORGANIZATION IS UNLIKELY...BUT PULSE STORMS AND AT LEAST SOME LINEAR FEATURES ALONG THE PRE-FRONTAL TROUGH WILL HAVE THE POTENTIAL TO PRODUCE AN ISOLATED WIND GUST OR LARGE HAIL STONE THIS AFTN. HIGH-RES HRRR AND NSSL WRF SUGGEST ONLY ISOLATED STORMS UNTIL THE PRE-FRONTAL TROUGH THIS EVENING...WHICH WILL BE THE PRIMARY DRIVER OF CONVECTION TODAY. BY THIS EVENING HOWEVER...WE BEGIN TO LOSE HEATING...AND HAVE CAPPED POP IN THE HIGH CHC RANGE. HIGHEST PROBABILITY FOR STORMS LOOKS TO BE ACROSS THE MIDDLE-PART OF THE CWA WHERE THE WESTWARD ADVANCING SEA BREEZE WILL INTERACT WITH THE EASTWARD MOVING TROUGH. CONVECTION WILL WANE AFTER DARK...AND LITTLE FANFARE IS EXPECTED WITH THE ACTUAL FROPA TONIGHT. HOWEVER...A SIGNIFICANT AIRMASS CHANGE WILL ACCOMPANY THIS FRONT...WITH MUCH DRIER AIR AND LOWS DROPPING INTO THE MID 60S AT THE COAST...AROUND 60 WELL INLAND. ALSO NEED TO NOTE A PERSISTENT AREA OF SEA-STRATUS FROM ABOUT NORTH MYRTLE BEACH TO BALD HEAD ISLAND. SHELF WATERS MUST BE JUST COOL ENOUGH TO TAP INTO THE IDEALIZED RESIDENCE PARCEL TIMES ENCOUNTERED BY THE W/SW WINDS IN ORDER TO SATURATE IN THIS AREA. THE COMBINATION OF THE BACKING WINDS WITHIN THE SEA BREEZE...AS WELL AS SIGNIFICANT HEATING JUST INLAND...SHOULD BREAK APART THIS STRATUS BY EARLY AFTN...BUT IT IS UNLIKELY THE NEAR-COAST AREA HERE WILL EXPERIENCE THE HOT/HUMID/SUNNY DAY GOING ON ELSEWHERE ACROSS THE CWA. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY... SOME VERY PLEASANT WEATHER EXPECTED THROUGH THE PERIOD. HIGH PRESSURE WELL TO OUR NORTH WILL SHOW LITTLE MOVEMENT WEDNESDAY WHILE THE TUESDAY NIGHT COLD FRONT STALLS WELL TO OUR SOUTH. IN BETWEEN THE TWO WE WILL SEE A N TO NE FLOW LOCALLY THAT WILL BRING SOME MUCH LOWER DEWPOINTS. A MILD LEVEL RIDGE WILL BE JUST TO OUR WEST ALLOWING FOR DEEP LAYER DRY AIR AND AMPLE SUNSHINE. ON THURSDAY THE HIGH WILL MOVE CLOSER TO THE REGION KEEPING TEMPERATURES A BIT BELOW CLIMATOLOGY. A LITTLE MOISTURE RETURN MAY GET UNDERWAY THURSDAY NIGHT AS THE HIGH MOVES FURTHER TO THE EAST, MAINLY OVER WESTERN ZONE. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...RETURN FLOW ON FRIDAY AND SATURDAY AS HIGH PRESSURE SITES OFF THE COAST. THE MID LEVEL RIDGE WILL BE OVERHEAD HOWEVER PRECLUDING DEEP MOISTURE AND CONFINING IT TO THE LOWER LEVELS. SO WHILE A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED OUT ANY COVERAGE SHOULD BE MINIMAL. OVER THE WEEKEND AND EVEN INTO MONDAY FOR THAT MATTER THE MID LEVEL RIDGING APPEARS TO RESURGE. DESPITE THIS THE GFS AND ECMWF BOTH DEPICT AN INCREASE IN PRECIPITATION COVERAGE. WHILE THE CONTINUED MOISTENING OF THE LOW LEVELS DOES IN FACT ARGUE FOR THIS THE MID LEVEL DRYNESS PROBABLY MEANS THAT ITS RATHER SUBTLE. TEMPERATURES MEANWHILE WILL GROW WARMER EACH DAY AND NIGHT. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...RETURN FLOW ON FRIDAY AND SATURDAY AS HIGH PRESSURE SITES OFF THE COAST. THE MID LEVEL RIDGE WILL BE OVERHEAD HOWEVER PRECLUDING DEEP MOISTURE AND CONFINING IT TO THE LOWER LEVELS. SO WHILE A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED OUT ANY COVERAGE SHOULD BE MINIMAL. OVER THE WEEKEND AND EVEN INTO MONDAY FOR THAT MATTER THE MID LEVEL RIDGING APPEARS TO RESURGE. DESPITE THIS THE GFS AND ECMWF BOTH DEPICT AN INCREASE IN PRECIPITATION COVERAGE. WHILE THE CONTINUED MOISTENING OF THE LOW LEVELS DOES IN FACT ARGUE FOR THIS THE MID LEVEL DRYNESS PROBABLY MEANS THAT ITS RATHER SUBTLE. TEMPERATURES MEANWHILE WILL GROW WARMER EACH DAY AND NIGHT. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...MID/HIGH CLOUDS ARE DECREASING FROM NW-SE WITH PATCHY IFR/MVFR CLOUDS MOVING SW-NE. AT KFLO IFR CIGS ARE OCCURRING. AT KCRE IFR/LIFR MARINE STRATUS IS OCCURRING AND MOVING NNE AND LIFTING INTO A MVFR LAYER AT KILM. WINDS ARE SSW 4-10 KTS. EXPECT LITTLE CHANGE OVER THE NEXT COUPLE OF HOURS. LOW CIGS WILL GRADUALLY BECOME VFR MID-LATE MORNING AS HEATING BEGINS. THEN THERE IS MODERATE TO HIGH CONFIDENCE VFR WILL PERSIST FOR THE REMAINDER OF THE TAF VALID PERIOD. A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF PERIOD. WINDS WILL INCREASE THIS MORNING WITH GUSTS TO AROUND 20KT. IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO DEVELOP. APPEARS MOST WILL DEVELOP BETWEEN THE INLAND AND COASTAL TERMINALS. WILL INDICATE VCSH IN TAFS AND AMEND LATER IF NECESSARY. CONVECTION SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT WILL MOVE THROUGH DURING THE LATE EVENING AND OVERNIGHT HOURS. EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM TUESDAY...HIGH PRESSURE OFFSHORE IS THE DOMINANT SYNOPTIC FEATURE ACROSS THE WATERS TODAY...DRIVING SW FLOW AND WINDS OF 10-15 KTS ACROSS THE WATERS. LOCAL ENHANCEMENTS OF UP TO 20 KTS...ALONG WITH A BACKING IN DIRECTION TO THE SOUTH...IS LIKELY ALONG THE SEA BREEZE THROUGH THE AFTN AS WELL. OTHER THAN SOME CHOPPY WATERS WITHIN THE NEAR SHORE WATERS THANKS TO THE SEA BREEZE...WAVE HEIGHTS ARE EXPECTED TO PERSIST AT 2-4 FT WITH A 6-7 SEC PERIOD DOMINANT. A COLD FRONT WILL CROSS THE WATERS LATE TONIGHT TURNING WINDS TO THE N/NW AT AROUND 15 KTS...AND PUSHING THE HIGHEST SEAS AWAY FROM THE COAST. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM TUESDAY... TUESDAY NIGHT`S FROPA WILL BRING A NORTHERLY FLOW ON WEDNESDAY. SURFACE HIGH REMAINS UP IN THE GREAT LAKES SO THE FLOW WILL BE QUITE LIGHT LOCALLY AND SEAS LIKELY JUST 2 TO 3 FT. JUST A SLIGHT VEER WEDNESDAY NIGHT WITH FLOW POSSIBLY GOING LIGHT AND VARIABLE FOR A TIME. THE HIGH EXTENDS JUST SLIGHTLY SOUTH ON THURSDAY WHILE PROGRESSING EAST. NE WINDS COULD INCREASE BY A CATEGORY AND BECOME A LITTLE GUSTY. THE COAST- PARALLEL FLOW WILL PRECLUDE MUCH BUILDING OF SEAS HOWEVER. .LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY... THE HIGH TO OUR NORTH PROGRESSES FURTHER EAST ON FRIDAY LEADING TO MORE VEERING LOCALLY. FRIDAY MAY SEE ONSHORE/EASTERLY FLOW MOST OF THE DAY WHILE A SOUTHERLY COMPONENT TRIES TO GET ESTABLISHED MAINLY OVER SOUTHERN ZONES. ON SATURDAY WE TRANSITION TO A FAIRLY NORMAL RETURN FLOW AROUND HIGH PRESSURE OFF THE EAST COAST. NOT A BERMUDA HIGH THOUGH WHICH TYPICALLY BRINGS SOUTHWESTERLY FLOW...THE WEEKEND WILL LIKELY SEE SOUTHEAST INSTEAD. THERE COULD BE A VERY GRADUAL INCREASE IN WAVE PERIOD AS A SWELL BECOMES ESTABLISHED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...JDW SHORT TERM...MBB LONG TERM...MBB AVIATION...MRR MARINE...JDW/MBB
AREA FORECAST DISCUSSION
NWS NORMAN OK
856 PM CDT WED MAY 13 2015 .UPDATE... MADE SOME ADJUSTMENTS TO THE PRECIP CHANCES THIS EVENING BASED ON LATEST RADAR TRENDS. THOUGHT ABOUT CANCELLING THE FLASH FLOOD WATCH... HOWEVER SOME OF THE HIGH RES MODELS KEEP THE CONVECTION IN SOUTHWEST MOVING ACROSS THE AREA OVERNIGHT. WITH ANTECEDENT CONDITIONS WOULD NOT TAKE MUCH ADDITIONAL RAINFALL TO CAUSE ADDITIONAL FLOODING. THEREFORE WILL KEEP WATCH GOING FOR NOW. OTHERWISE... NOT OTHER CHANGES AT THIS POINT. && .PREV DISCUSSION... /ISSUED 615 PM CDT WED MAY 13 2015/ AVIATION... 0Z TAFS... IFR/LIFR CEILINGS WILL CONT THIS EVENING. CEILINGSWILL LIKELY IMPROVE THURSDAY WITH EVERYONE EVENTUALLY AT MVFR/VFR LEVELS. RAIN... HEAVY AT TIMES WILL CONTINUE TO MOVE ACROSS THE REGION TONIGHT... GRADUALLY ENDING FROM WEST TO EAST. HOWEVER SOME LOWERED VISIBILITIES WILL BE POSSIBLE THROUGH THU MORNING. THUNDERSTORMS WILL ALSO BE POSSIBLE THIS EVENING. PREV DISCUSSION... /ISSUED 412 PM CDT WED MAY 13 2015/ DISCUSSION... PRIMARY PRECIPITATION SHIELD CONTINUES TO PIVOT EAST THROUGH CENTRAL AND EASTERN PORTIONS OF THE COUNTY WARNING AREA... ALTHOUGH CONVECTION IS REDEVELOPING IN THE TEXAS PANHANDLE AND WEST TEXAS WHICH MAY MOVE INTO WESTERN PORTIONS OF THE AREA THIS AFTERNOON AND EVENING AGAIN. HRRR AND OUNWRF SHOW THAT THIS MAY PERSIST FOR A WHILE THIS EVENING IN WESTERN OKLAHOMA/NORTH TEXAS BUT LIMITED INSTABILITY SHOULD PREVENT STORMS WIDESPREAD STORMS. OVERALL... STILL EXPECT GENERAL DECREASE IN PRECIPITATION FROM WEST TO EAST OVERNIGHT AND EARLY TOMORROW MORNING AS SHORTWAVE MOVES NORTHEAST PAST THE AREA. FLASH FLOOD WATCH STILL LOOKS GOOD AS THE MODERATE RAINFALL CAN STILL CAUSE FLOODING ISSUES BECAUSE OF THE HEAVY RECENT RAINFALL. STORMS EXPECTED AGAIN THURSDAY NIGHT INTO FRIDAY WITH MOISTURE INCREASE AND PERHAPS A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE PRIMARY UPPER TROUGH APPROACHES AND INCREASES POPS SIGNIFICANTLY FRIDAY NIGHT AND SATURDAY. DECENT SIGNAL OF A COMPLEX DEVELOPING WEST AND MOVING INTO THE AREA SATURDAY MORNING WITH REDEVELOPMENT EXPECTED AGAIN ON SATURDAY. THERE ARE STILL SOME QUESTIONS ON THE EXPECTED EVOLUTION ON SATURDAY... BUT STILL WILL BE LOOKING AT THE SEVERE WEATHER POTENTIAL FOR SATURDAY AS WE GET CLOSER. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 60 80 65 79 / 50 20 30 40 HOBART OK 58 80 62 81 / 70 10 40 30 WICHITA FALLS TX 61 82 65 82 / 70 10 40 40 GAGE OK 55 83 60 82 / 40 10 30 20 PONCA CITY OK 58 80 65 80 / 90 30 20 30 DURANT OK 63 81 66 79 / 60 40 30 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR OKZ007-008-012-013- 017>020-022>048-050>052. TX...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR TXZ083>090. && $$ 30/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
615 PM CDT WED MAY 13 2015 .AVIATION... 0Z TAFS... IFR/LIFR CEILINGS WILL CONT THIS EVENING. CEILINGSWILL LIKELY IMPROVE THURSDAY WITH EVERYONE EVENTUALLY AT MVFR/VFR LEVELS. RAIN... HEAVY AT TIMES WILL CONTINUE TO MOVE ACROSS THE REGION TONIGHT... GRADUALLY ENDING FROM WEST TO EAST. HOWEVER SOME LOWERED VISIBILITIES WILL BE POSSIBLE THROUGH THU MORNING. THUNDERSTORMS WILL ALSO BE POSSIBLE THIS EVENING. && .PREV DISCUSSION... /ISSUED 412 PM CDT WED MAY 13 2015/ DISCUSSION... PRIMARY PRECIPITATION SHIELD CONTINUES TO PIVOT EAST THROUGH CENTRAL AND EASTERN PORTIONS OF THE COUNTY WARNING AREA... ALTHOUGH CONVECTION IS REDEVELOPING IN THE TEXAS PANHANDLE AND WEST TEXAS WHICH MAY MOVE INTO WESTERN PORTIONS OF THE AREA THIS AFTERNOON AND EVENING AGAIN. HRRR AND OUNWRF SHOW THAT THIS MAY PERSIST FOR A WHILE THIS EVENING IN WESTERN OKLAHOMA/NORTH TEXAS BUT LIMITED INSTABILITY SHOULD PREVENT STORMS WIDESPREAD STORMS. OVERALL... STILL EXPECT GENERAL DECREASE IN PRECIPITATION FROM WEST TO EAST OVERNIGHT AND EARLY TOMORROW MORNING AS SHORTWAVE MOVES NORTHEAST PAST THE AREA. FLASH FLOOD WATCH STILL LOOKS GOOD AS THE MODERATE RAINFALL CAN STILL CAUSE FLOODING ISSUES BECAUSE OF THE HEAVY RECENT RAINFALL. STORMS EXPECTED AGAIN THURSDAY NIGHT INTO FRIDAY WITH MOISTURE INCREASE AND PERHAPS A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE PRIMARY UPPER TROUGH APPROACHES AND INCREASES POPS SIGNIFICANTLY FRIDAY NIGHT AND SATURDAY. DECENT SIGNAL OF A COMPLEX DEVELOPING WEST AND MOVING INTO THE AREA SATURDAY MORNING WITH REDEVELOPMENT EXPECTED AGAIN ON SATURDAY. THERE ARE STILL SOME QUESTIONS ON THE EXPECTED EVOLUTION ON SATURDAY... BUT STILL WILL BE LOOKING AT THE SEVERE WEATHER POTENTIAL FOR SATURDAY AS WE GET CLOSER. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 60 80 65 79 / 80 20 30 40 HOBART OK 58 80 62 81 / 50 10 40 30 WICHITA FALLS TX 61 82 65 82 / 50 10 40 40 GAGE OK 55 83 60 82 / 60 10 30 20 PONCA CITY OK 58 80 65 80 / 90 30 20 30 DURANT OK 63 81 66 79 / 80 40 30 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR OKZ007-008-012- 013-017>020-022>048-050>052. TX...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR TXZ083>090. && $$ 30/25/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
1248 PM CDT TUE MAY 12 2015 .AVIATION... 18Z TAFS...VFR CONDITIONS EXPECTED MUCH OF THE TAF PERIOD. FROM 06Z THROUGH 12Z WED...LOW LEVEL MOISTURE WILL INCREASE...RESULTING MVFR/IFR CIGS SPREADING FROM SW TO NE ACROSS THE REGION...ALONG WITH LIGHT TO MODERATE RAINFALL. RAIN MAY BECOME HEAVY AT TIMES DURING THE DAY WED...WITH VSBYS LESS THAN 2 MILES...BUT CONFIDENCE IN THESE VSBYS IS TOO LOW TO MENTION IN TAFS. FOR NOW WILL GO WITH PREVAILING -RA AT SOUTHWESTERN TERMINALS...WHERE CONFIDENCE IN RAIN IS HIGHER. && .PREV DISCUSSION... /ISSUED 1100 AM CDT TUE MAY 12 2015/ UPDATE... ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES. DISCUSSION... ALTHOUGH MID-HIGH CLOUDS WILL THIN SOMEWHAT FROM WEST TO EAST THROUGH THE AFTERNOON...MOST AREAS OUTSIDE OF FAR NORTH/WEST OKLAHOMA WILL STAY MOSTLY CLOUDY TODAY AND WILL KEEP TEMPS FROM GETTING TOO WARM. INCREASED CLOUD COVER AND LOWERED HIGHS A FEW DEGREES NEAR AND SOUTH OF OKC. A FEW SPRINKLES MAY MOVE INTO WESTERN NORTH TEXAS THIS AFTERNOON BUT MAIN RAIN EVENT STILL APPEARS TO COMMENCE AFTER MIDNIGHT TONIGHT AND MAINLY DURING THE DAY TOMORROW. FLASH FLOOD WATCH WILL BE CONTINUED FOR LATE TONIGHT AND TOMORROW. LATEST RUN OF MODELS LOOKS FAVORABLE FOR HEAVIER RAIN AXIS TO BE FARTHER WEST...SOME OF WHICH WILL BE JUST OUTSIDE OF CURRENT WATCH. HOWEVER...AREAS WEST OF THE FLASH FLOOD WATCH CAN TAKE MUCH MORE RAIN THAN THE RAIN SOAKED CENTRAL/SOUTHEAST OKLAHOMA. WE WILL TAKE A CLOSER LOOK TO EXPANDING THE WATCH BUT IT WILL NOT BE DONE WITH THIS UPDATE. ALTHOUGH SEVERE WEATHER DOES LOOK POSSIBLE FRIDAY...STILL APPEARS THAT SATURDAY COULD BE THE PRIMARY IMPACT DAY FOR SEVERE WEATHER. PREV DISCUSSION... /ISSUED 615 AM CDT TUE MAY 12 2015/ AVIATION... 12Z TAFS...THIN BAND OF SHOWERS AND EMBEDDED STORMS ACROSS CENTRAL AND WEST TEXAS IS EXPECTED TO REMAIN SOUTH OF TAF SITES THROUGH THE DAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH 6Z...BEFORE CEILINGS LOWER ACROSS WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA AS PRECIPITATION DEVELOPS. PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 12 2015/ DISCUSSION... EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS. THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP IN CHANCE POPS FOR OUR TEXAS COUNTIES. ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT. WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN. BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING ANOTHER PERIOD OF DRY WEATHER. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 56 67 62 79 / 30 100 100 30 HOBART OK 56 67 61 80 / 40 100 70 20 WICHITA FALLS TX 59 70 64 82 / 60 100 70 30 GAGE OK 53 66 56 81 / 20 80 60 10 PONCA CITY OK 53 66 59 79 / 10 70 100 50 DURANT OK 59 71 64 80 / 40 80 70 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OKZ007-008-012-013-017>020-022>048-050>052. TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR TXZ083>090. && $$ 11/84
AREA FORECAST DISCUSSION
NWS NORMAN OK
1100 AM CDT TUE MAY 12 2015 .UPDATE... ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES. && .DISCUSSION... ALTHOUGH MID-HIGH CLOUDS WILL THIN SOMEWHAT FROM WEST TO EAST THROUGH THE AFTERNOON...MOST AREAS OUTSIDE OF FAR NORTH/WEST OKLAHOMA WILL STAY MOSTLY CLOUDY TODAY AND WILL KEEP TEMPS FROM GETTING TOO WARM. INCREASED CLOUD COVER AND LOWERED HIGHS A FEW DEGREES NEAR AND SOUTH OF OKC. A FEW SPRINKLES MAY MOVE INTO WESTERN NORTH TEXAS THIS AFTERNOON BUT MAIN RAIN EVENT STILL APPEARS TO COMMENCE AFTER MIDNIGHT TONIGHT AND MAINLY DURING THE DAY TOMORROW. FLASH FLOOD WATCH WILL BE CONTINUED FOR LATE TONIGHT AND TOMORROW. LATEST RUN OF MODELS LOOKS FAVORABLE FOR HEAVIER RAIN AXIS TO BE FARTHER WEST...SOME OF WHICH WILL BE JUST OUTSIDE OF CURRENT WATCH. HOWEVER...AREAS WEST OF THE FLASH FLOOD WATCH CAN TAKE MUCH MORE RAIN THAN THE RAIN SOAKED CENTRAL/SOUTHEAST OKLAHOMA. WE WILL TAKE A CLOSER LOOK TO EXPANDING THE WATCH BUT IT WILL NOT BE DONE WITH THIS UPDATE. ALTHOUGH SEVERE WEATHER DOES LOOK POSSIBLE FRIDAY...STILL APPEARS THAT SATURDAY COULD BE THE PRIMARY IMPACT DAY FOR SEVERE WEATHER. && .PREV DISCUSSION... /ISSUED 615 AM CDT TUE MAY 12 2015/ AVIATION... 12Z TAFS...THIN BAND OF SHOWERS AND EMBEDDED STORMS ACROSS CENTRAL AND WEST TEXAS IS EXPECTED TO REMAIN SOUTH OF TAF SITES THROUGH THE DAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH 6Z...BEFORE CEILINGS LOWER ACROSS WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA AS PRECIPITATION DEVELOPS. PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 12 2015/ DISCUSSION... EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS. THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP IN CHANCE POPS FOR OUR TEXAS COUNTIES. ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT. WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN. BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING ANOTHER PERIOD OF DRY WEATHER. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 70 56 67 62 / 0 30 100 100 HOBART OK 71 56 67 61 / 0 40 100 70 WICHITA FALLS TX 71 59 70 64 / 10 60 100 70 GAGE OK 70 53 66 56 / 0 20 80 60 PONCA CITY OK 71 53 66 59 / 0 10 70 100 DURANT OK 72 59 71 64 / 10 40 80 70 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OKZ007-008-012-013-017>020-022>048-050>052. TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR TXZ083>090. && $$ 11/84
AREA FORECAST DISCUSSION
NWS NORMAN OK
615 AM CDT TUE MAY 12 2015 .AVIATION... 12Z TAFS...THIN BAND OF SHOWERS AND EMBEDDED STORMS ACROSS CENTRAL AND WEST TEXAS IS EXPECTED TO REMAIN SOUTH OF TAF SITES THROUGH THE DAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH 6Z...BEFORE CEILINGS LOWER ACROSS WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA AS PRECIPITATION DEVELOPS. && .PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 12 2015/ DISCUSSION... EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS. THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP IN CHANCE POPS FOR OUR TEXAS COUNTIES. ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT. WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN. BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING ANOTHER PERIOD OF DRY WEATHER. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 71 56 67 62 / 0 30 80 80 HOBART OK 71 56 67 61 / 0 40 90 70 WICHITA FALLS TX 72 59 70 64 / 10 60 90 70 GAGE OK 71 53 66 56 / 0 20 70 60 PONCA CITY OK 72 53 66 59 / 0 10 70 90 DURANT OK 73 59 71 64 / 10 40 80 70 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OKZ007-008-012-013-017>020-022>048-050>052. TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR TXZ083>090. && $$
AREA FORECAST DISCUSSION
NWS NORMAN OK
325 AM CDT TUE MAY 12 2015 .DISCUSSION... EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS. THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP IN CHANCE POPS FOR OUR TEXAS COUNTIES. ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT. WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN. BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING ANOTHER PERIOD OF DRY WEATHER. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 71 56 67 62 / 0 30 80 80 HOBART OK 71 56 67 61 / 0 40 90 70 WICHITA FALLS TX 72 59 70 64 / 10 60 90 70 GAGE OK 71 53 66 56 / 0 20 70 60 PONCA CITY OK 72 53 66 59 / 0 10 70 90 DURANT OK 73 59 71 64 / 10 40 80 70 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OKZ007-008-012-013-017>020-022>048-050>052. TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR TXZ083>090. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MEDFORD OR
731 PM PDT WED MAY 13 2015 UPDATED AVIATION .SHORT TERM...WATER VAPOR IMAGERY THIS AFTERNOON SHOWS A DEEP LONGWAVE TROUGH OVER THE NORTHEAST PACIFIC WATERS EXTENDING INLAND THROUGH THE FAR WESTERN CONUS. EMBEDDED IN THIS LARGE TROUGH ARE SEVERAL WELL- DEFINED SHORTWAVE TROUGHS FROM COASTAL CALIFORNIA NORTH TROUGH EASTERN WASHINGTON. CLOSER TO HOME...WE`RE DEALING WITH SHORTWAVE ENERGY MOVING SOUTH TO NORTH OVER NORTHERN CALIFORNIA...AND THIS WILL COMBINE WITH SOME INSTABILITY OVER THE FORECAST AREA TO GENERATE SHOWERS AND SOME THUNDERSTORMS THIS AFTERNOON. LATEST HRRR GUIDANCE HAS HELPED US REFINE AREAS FOR THUNDERSTORM POTENTIAL...AND WE HAVE SPREAD THE CHANCES ALL THE WAY INTO THE UMPQUA BASIN LATE THIS AFTERNOON BASED ON THIS OUTPUT. STORMS WILL TRACK SOUTH- SOUTHEAST TO NORTH-NORTHWEST SO ANY SHOWERS AND STORMS OVER THE SISKIYOUS AND CASCADES HAVE THE POTENTIAL TO MOVE OVER THE MEDFORD AREA THIS AFTERNOON/EVENING. TONIGHT...SHORTWAVE ENERGY WILL BE OVERHEAD AND WILL MAINTAIN THE CHANCE FOR SHOWERS FOR MOST OF THE CWA. WE HAVE DECIDED TO KEEP THUNDERSTORMS OUT OF THE FORECAST OVERNIGHT BECAUSE IT DOES NOT SEEM LIKE INSTABILITY ALOFT IS FAVORABLE ENOUGH TO SUPPORT NOCTURNAL STORMS. TOMORROW SHOULD BE THE BEST CHANCE FOR THUNDERSTORMS OVER A WIDE AREA OF SOUTHERN OREGON AND NORTHERN CALIFORNIA. INSTABILITY INCREASES SUBTLY THROUGH MUCH OF THE ATMOSPHERIC COLUMN TOMORROW AND SHORTWAVE ENERGY WILL BE OF MODERATE STRENGTH. GFS40 850MB COMPUTED LIFTED INDICES ARE ZERO OR SLIGHTLY NEGATIVE AND THIS SUPPORTS A SLIGHT CHANCE OF THUNDERSTORMS. BULK SHEAR FROM 0-6KM IS HIGHER TOMORROW SO THERE IS A BETTER CHANCE FOR A FEW STRONG STORMS. ON FRIDAY...THE UPPER LOW THAT`S THE SOURCE OF ENERGY FOR OUR SHOWERS WILL PUSH INTO NEVADA AND PRECIPITATION CHANCES WILL BE FOCUSED EAST OF THE CASCADES. THE LOW PROGRESSION CONTINUES EASTWARD AND BY SATURDAY THERE IS INCREASED STABILITY AND LITTLE TO NO SHORTWAVE ACTIVITY...SO WE HAVE REMOVED RAIN CHANCES FOR A GOOD PORTION OF THE FORECAST AREA. IN SHORT...SATURDAY SHOULD BE THE DRIEST DAY OF THE WEEK. .LONG TERM...SUNDAY MAY 17TH THROUGH WEDNESDAY MAY 20TH...NOT MANY CHANGES MADE TO THE LONG TERM. MODELS ARE STILL IN GOOD AGREEMENT ON A GENERAL LONG WAVE TROUGH PATTERN REMAINING OVER THE AREA. THIS LENDS TO HIGH CONFIDENCE THAT UNSETTLED WEATHER WILL CONTINUE THROUGH THE EXTENDED PERIOD. MODELS SHOW MARGINAL INSTABILITY DURING THE AFTERNOONS AND EVENINGS THROUGH THIS TIME FRAME AND IS ENOUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS OVER THE CASCADES AND EAST SIDE. TEMPERATURES WILL REMAIN WITHIN A FEW DEGREES OF NORMAL THROUGH THE EXTENDED AND DAY TO DAY VARIABILITY WILL BE MINIMAL. MND && .AVIATION...FOR THE 14/00Z TAF CYCLE...SOME THUNDERSTORM ACTIVITY IN SISKIYOU AND MODOC COUNTY. STORMS ARE EXPECTED TO SPREAD NORTHWARD AND TRANSITION TO ORDINARY SHOWERS WITHIN THE NEXT FEW HOURS. SHOWERS AND MOSTLY CLOUDY TO OVERCAST SKIES WILL CONTINUE THROUGH TOMORROW EVENING OVER MOST OF AREA, WITH NEARLY ALL TERMINALS LIKELY TO SEE AT LEAST A SHOWER IN THE VICINITY. CIGS ARE EXPECTED TO DROP AND REMAIN PRIMARILY MVFR TONIGHT ALONG THE COAST AND IN THE UMPQUA BASIN...WITH LOCAL AREAS OF IFR AND PARTIAL TERRAIN OBSCURATION. MVFR CIGS WILL DEVELOP IN OTHER WEST SIDE VALLEYS BY THURSDAY MORNING. CIGS SHOULD LIFT TO VFR BY THURSDAY AFTERNOON. CASCADES AND EAST...MOSTLY VFR CIGS WITH AREAS OF TERRAIN OBSCURATION AND LOCAL AREAS OF MVFR. POSSIBLE ISOLATED THUNDERSTORMS THURSDAY AFTERNOON. -MSC && .MARINE...UPDATED 230 PM PDT WEDNESDAY, MAY 13, 2015...WINDS WILL REMAIN WEAK TONIGHT AND PRIMARILY SOUTHERLY. SCATTERED LIGHT SHOWERS WILL AFFECT THE WATERS THROUGH THURSDAY AFTERNOON AS AN UPPER LOW CURRENTLY CENTERED ROUGHLY 400 MILES WEST OF VANCOUVER ISLAND TRACKS SOUTH/SOUTHEASTWARD. NORTHWESTERLY SWELL ASSOCIATED WITH THIS SYSTEM WILL CONTINUE BUILDING THIS EVENING INTO THURSDAY, CAUSING MODERATE SEAS. NORTHERLY WINDS WILL INCREASE THURSDAY EVENING, BUT ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. WINDS WILL BE STRONGEST SOUTH OF CAPE BLANCO. SEAS BEGIN DIMINISHING THURSDAY NIGHT, AND WILL REMAIN RELATIVELY CALM THROUGH THE WEEKEND. WINDS WILL REMAIN NORTHERLY TO NORTHWESTERLY AND MODERATE THROUGH THE WEEKEND. BOTH 13/12Z GFS AND EC SHOW SIMILAR LOW PRESSURE SYSTEMS THIS WEEKEND FORMING FAR ENOUGH OFFSHORE TO KEEP WINDS BELOW ADVISORY CRITERIA. -MSC && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PACIFIC COASTAL WATERS...NONE. $$ NSK/BPN/MND/MSC
AREA FORECAST DISCUSSION...UPDATED
NWS MEDFORD OR
729 PM PDT WED MAY 13 2015 UPDATED AVIATION DISCUSSION .SHORT TERM...WATER VAPOR IMAGERY THIS AFTERNOON SHOWS A DEEP LONGWAVE TROUGH OVER THE NORTHEAST PACIFIC WATERS EXTENDING INLAND THROUGH THE FAR WESTERN CONUS. EMBEDDED IN THIS LARGE TROUGH ARE SEVERAL WELL- DEFINED SHORTWAVE TROUGHS FROM COASTAL CALIFORNIA NORTH TROUGH EASTERN WASHINGTON. CLOSER TO HOME...WE`RE DEALING WITH SHORTWAVE ENERGY MOVING SOUTH TO NORTH OVER NORTHERN CALIFORNIA...AND THIS WILL COMBINE WITH SOME INSTABILITY OVER THE FORECAST AREA TO GENERATE SHOWERS AND SOME THUNDERSTORMS THIS AFTERNOON. LATEST HRRR GUIDANCE HAS HELPED US REFINE AREAS FOR THUNDERSTORM POTENTIAL...AND WE HAVE SPREAD THE CHANCES ALL THE WAY INTO THE UMPQUA BASIN LATE THIS AFTERNOON BASED ON THIS OUTPUT. STORMS WILL TRACK SOUTH- SOUTHEAST TO NORTH-NORTHWEST SO ANY SHOWERS AND STORMS OVER THE SISKIYOUS AND CASCADES HAVE THE POTENTIAL TO MOVE OVER THE MEDFORD AREA THIS AFTERNOON/EVENING. TONIGHT...SHORTWAVE ENERGY WILL BE OVERHEAD AND WILL MAINTAIN THE CHANCE FOR SHOWERS FOR MOST OF THE CWA. WE HAVE DECIDED TO KEEP THUNDERSTORMS OUT OF THE FORECAST OVERNIGHT BECAUSE IT DOES NOT SEEM LIKE INSTABILITY ALOFT IS FAVORABLE ENOUGH TO SUPPORT NOCTURNAL STORMS. TOMORROW SHOULD BE THE BEST CHANCE FOR THUNDERSTORMS OVER A WIDE AREA OF SOUTHERN OREGON AND NORTHERN CALIFORNIA. INSTABILITY INCREASES SUBTLY THROUGH MUCH OF THE ATMOSPHERIC COLUMN TOMORROW AND SHORTWAVE ENERGY WILL BE OF MODERATE STRENGTH. GFS40 850MB COMPUTED LIFTED INDICES ARE ZERO OR SLIGHTLY NEGATIVE AND THIS SUPPORTS A SLIGHT CHANCE OF THUNDERSTORMS. BULK SHEAR FROM 0-6KM IS HIGHER TOMORROW SO THERE IS A BETTER CHANCE FOR A FEW STRONG STORMS. ON FRIDAY...THE UPPER LOW THAT`S THE SOURCE OF ENERGY FOR OUR SHOWERS WILL PUSH INTO NEVADA AND PRECIPITATION CHANCES WILL BE FOCUSED EAST OF THE CASCADES. THE LOW PROGRESSION CONTINUES EASTWARD AND BY SATURDAY THERE IS INCREASED STABILITY AND LITTLE TO NO SHORTWAVE ACTIVITY...SO WE HAVE REMOVED RAIN CHANCES FOR A GOOD PORTION OF THE FORECAST AREA. IN SHORT...SATURDAY SHOULD BE THE DRIEST DAY OF THE WEEK. LONG TERM...SUNDAY MAY 17TH THROUGH WEDNESDAY MAY 20TH...NOT MANY CHANGES MADE TO THE LONG TERM. MODELS ARE STILL IN GOOD AGREEMENT ON A GENERAL LONG WAVE TROUGH PATTERN REMAINING OVER THE AREA. THIS LENDS TO HIGH CONFIDENCE THAT UNSETTLED WEATHER WILL CONTINUE THROUGH THE EXTENDED PERIOD. MODELS SHOW MARGINAL INSTABILITY DURING THE AFTERNOONS AND EVENINGS THROUGH THIS TIME FRAME AND IS ENOUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS OVER THE CASCADES AND EAST SIDE. TEMPERATURES WILL REMAIN WITHIN A FEW DEGREES OF NORMAL THROUGH THE EXTENDED AND DAY TO DAY VARIABILITY WILL BE MINIMAL. MND AVIATION...FOR THE 14/00Z TAF CYCLE...FOR THE 14/00Z TAF CYCLE...SOME THUNDERSTORM ACTIVITY IN SISKIOY AND MODOC COUNTY. STORMS ARE EXPECTED TO SPREAD NORTHWARD AND TRANSITION TO ORDINARY SHOWERS WITHIN THE NEXT FEW HOURS. SHOWERS AND MOSTLY CLOUDY TO OVERCAST SKIES WILL CONTINUE THROUGH TOMORROW EVENING OVER MOST OF AREA, WITH NEARLY ALL TERMINALS LIKELY TO SEE AT LEAST A SHOWER IN THE VICINITY. CIGS ARE EXPECTED TO DROP AND REMAIN PRIMARILY MVFR TONIGHT ALONG THE COAST AND IN THE UMPQUA BASIN...WITH LOCAL AREAS OF IFR AND PARTIAL TERRAIN OBSCURATION. MVFR CIGS WILL DEVELOP IN OTHER WEST SIDE VALLEYS BY THURSDAY MORNING. CIGS SHOULD LIFT TO VFR BY THURSDAY AFTERNOON. CASCADES AND EAST...MOSTLY VFR CIGS WITH AREAS OF TERRAIN OBSCURATION AND LOCAL AREAS OF MVFR. POSSIBLE ISOLATED THUNDERSTORMS THURSDAY AFTERNOON. -MSC MARINE...UPDATED 230 PM PDT WEDNESDAY, MAY 13, 2015...WINDS WILL REMAIN WEAK TONIGHT AND PRIMARILY SOUTHERLY. SCATTERED LIGHT SHOWERS WILL AFFECT THE WATERS THROUGH THURSDAY AFTERNOON AS AN UPPER LOW CURRENTLY CENTERED ROUGHLY 400 MILES WEST OF VANCOUVER ISLAND TRACKS SOUTH/SOUTHEASTWARD. NORTHWESTERLY SWELL ASSOCIATED WITH THIS SYSTEM WILL CONTINUE BUILDING THIS EVENING INTO THURSDAY, CAUSING MODERATE SEAS. NORTHERLY WINDS WILL INCREASE THURSDAY EVENING, BUT ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. WINDS WILL BE STRONGEST SOUTH OF CAPE BLANCO. SEAS BEGIN DIMINISHING THURSDAY NIGHT, AND WILL REMAIN RELATIVELY CALM THROUGH THE WEEKEND. WINDS WILL REMAIN NORTHERLY TO NORTHWESTERLY AND MODERATE THROUGH THE WEEKEND. BOTH 13/12Z GFS AND EC SHOW SIMILAR LOW PRESSURE SYSTEMS THIS WEEKEND FORMING FAR ENOUGH OFFSHORE TO KEEP WINDS BELOW ADVISORY CRITERIA. -MSC && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PACIFIC COASTAL WATERS...NONE. $$ NSK/BPN/MND/MSC
AREA FORECAST DISCUSSION...UPDATE
NWS PENDLETON OR
351 PM PDT TUE MAY 12 2015 UPDATED FOR AVIATION DISCUSSION .SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY NIGHT. AN INTENSE AND STATIONARY LOW PRESSURE SYSTEM OVER THE PACNW WILL CONTINUE TO PUMP MOISTURE INTO OUR AREA AND COMBINING THIS WITH DAYTIME HEATING WILL PRODUCE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING. THE TSRA COULD BECOME STRONG AND PRODUCE GUSTY WINDS AND HAIL WITH THE BEST CHANCES OF THIS OCCURRING OVER THE EASTERN ZONES THAT INCLUDES IN AND AROUND THE BLUE/WALLOWA MOUNTAINS AS WELL AS GRANT COUNTY. ELSEWHERE SHOWERS WILL CONTINUE DEVELOPING ACROSS THE REGION INTO THIS EVENING. AS THE LOW DRIFTS INTO NE OREGON LATER TONIGHT MOISTURE WILL RAP AROUND THIS SYSTEM AND INTO THE EASTERN PORTIONS OF THE AREA AND MODERATE TO HEAVY RAINFALL IS POSSIBLE WITH UP TO AN INCH IN SOME LOCATIONS. THE LOW AND THE BULK OF THE MOISTURE DRIFT NORTH WEDNESDAY MORNING WITH DECREASING CHANCES OF PCPN EXPECTED BUT THE CLOUDS AND SHOWERS WILL PERSIST INTO WEDNESDAY AFTERNOON. A WEAK DISTURBANCE WILL NEAR CENTRAL OREGON WEDNESDAY AFTERNOON THAT COULD PRODUCE AN ISOLD TSRA. OTHERWISE THE BEST CHANCES FOR PCPN SHOULD OCCUR ALONG THE WA/OR CASCADES WEDNESDAY NIGHT AND THURSDAY. BY THURSDAY ANOTHER LOW PRESSURE SYSTEM WILL TRACK TO OUR SOUTH BUT SHOWERS FROM THIS SYSTEM WILL MOVE NORTH AND INTO MOST PORTIONS OF OUR AREA THURSDAY NIGHT. AFTERNOON TEMPERATURES WILL REMAIN COOL TOMORROW BEFORE WARMER TEMPERATURES CAN BE EXPECTED THURSDAY. && .LONG TERM...FRIDAY THROUGH MONDAY NIGHT...MILD YET UNSETTLED WEATHER CAN BE EXPECTED FOR THE EXTENDED. A LOW PRESSURE SYSTEM CENTERED OVER CENTRAL NEVADA WILL CONTINUE TO SPIN UP MOISTURE AND POSSIBLE THUNDERSTORMS TO THE AREA ON FRIDAY. THIS SYSTEM WILL EXIT THE AREA FRIDAY NIGHT WITH ANOTHER LOW MOVING TOWARDS THE PACIFIC COAST ON SATURDAY. THIS LOW IS CURRENTLY FORECAST TO TRACK SOUTH OF THE CWA TOWARDS THE NORTHERN CALIFORNIA COAST THROUGH THE WEEKEND. THIS WILL ALLOW FOR MORE MOISTURE AND INSTABILITY TO BE SPUN UP OVER THE AREA...PROVIDING ANOTHER CHANCE FOR THUNDERSTORMS. THE LOW IS EXPECTED TO SLOWLY MOVE INLAND AND BE CENTERED OVER THE CA/NV BOARDER ON MONDAY NIGHT. OVERALL THE AIRMASS SHOULD BE FAIRLY WARM OVER THE AREA...KEEPING THE TEMPERATURES NEAR TO ABOVE NORMAL. REASONABLE CLOUD COVER CAN BE EXPECTED AT NIGHT AS WELL...ALLOWING FOR MILD NIGHTTIME LOWS. WEBER && .AVIATION...00Z TAFS...MVFR CONDITIONS CAN BE EXPECTED OVER THE NEXT 12-18 HOURS...AS A DEFORMATION BAND IS EXPECTED TO SET UP OVER SOUTHERN WASHINGTON DURING THIS PERIOD. THIS COULD ALLOW FOR PERIODS OF MODERATE RAIN...WITH CIGS POSSIBLY FALLING TO IFR CATEGORIES. FOR NOW PROB30 GROUPS COVER THE PERIODS OF CONCERN. STILL POSSIBLE -TSRA AT KPDT AND KALW FROM 0Z-3Z THIS AFTERNOON...BUT DUE TO LOWER CONFIDENCE HAVE REMOVED THE TEMPO GROUP FOR THUNDER AND JUST LEFT SHOWERS. WINDS WILL RANGE FROM 5 TO 15 KTS...WITH GUSTS UP TO 25 KTS. WEBER && .PRELIMINARY POINT TEMPS/POPS... PDT 45 62 45 64 / 90 70 10 30 ALW 48 65 46 69 / 90 80 10 30 PSC 51 70 46 70 / 90 80 10 20 YKM 49 68 43 70 / 80 70 40 20 HRI 49 69 44 70 / 80 70 10 30 ELN 47 66 41 70 / 90 80 40 20 RDM 35 60 36 59 / 50 30 30 50 LGD 43 62 41 64 / 100 70 20 30 GCD 41 63 39 65 / 80 20 20 50 DLS 48 65 46 71 / 60 50 30 30 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. && FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT... WWW.WEATHER.GOV/PENDLETON $$ 97/89/89
AREA FORECAST DISCUSSION
NWS PENDLETON OR
225 PM PDT TUE MAY 12 2015 .SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY NIGHT. AN INTENSE AND STATIONARY LOW PRESSURE SYSTEM OVER THE PACNW WILL CONTINUE TO PUMP MOISTURE INTO OUR AREA AND COMBINING THIS WITH DAYTIME HEATING WILL PRODUCE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING. THE TSRA COULD BECOME STRONG AND PRODUCE GUSTY WINDS AND HAIL WITH THE BEST CHANCES OF THIS OCCURRING OVER THE EASTERN ZONES THAT INCLUDES IN AND AROUND THE BLUE/WALLOWA MOUNTAINS AS WELL AS GRANT COUNTY. ELSEWHERE SHOWERS WILL CONTINUE DEVELOPING ACROSS THE REGION INTO THIS EVENING. AS THE LOW DRIFTS INTO NE OREGON LATER TONIGHT MOISTURE WILL RAP AROUND THIS SYSTEM AND INTO THE EASTERN PORTIONS OF THE AREA AND MODERATE TO HEAVY RAINFALL IS POSSIBLE WITH UP TO AN INCH IN SOME LOCATIONS. THE LOW AND THE BULK OF THE MOISTURE DRIFT NORTH WEDNESDAY MORNING WITH DECREASING CHANCES OF PCPN EXPECTED BUT THE CLOUDS AND SHOWERS WILL PERSIST INTO WEDNESDAY AFTERNOON. A WEAK DISTURBANCE WILL NEAR CENTRAL OREGON WEDNESDAY AFTERNOON THAT COULD PRODUCE AN ISOLD TSRA. OTHERWISE THE BEST CHANCES FOR PCPN SHOULD OCCUR ALONG THE WA/OR CASCADES WEDNESDAY NIGHT AND THURSDAY. BY THURSDAY ANOTHER LOW PRESSURE SYSTEM WILL TRACK TO OUR SOUTH BUT SHOWERS FROM THIS SYSTEM WILL MOVE NORTH AND INTO MOST PORTIONS OF OUR AREA THURSDAY NIGHT. AFTERNOON TEMPERATURES WILL REMAIN COOL TOMORROW BEFORE WARMER TEMPERATURES CAN BE EXPECTED THURSDAY. && .LONG TERM...FRIDAY THROUGH MONDAY NIGHT...MILD YET UNSETTLED WEATHER CAN BE EXPECTED FOR THE EXTENDED. A LOW PRESSURE SYSTEM CENTERED OVER CENTRAL NEVADA WILL CONTINUE TO SPIN UP MOISTURE AND POSSIBLE THUNDERSTORMS TO THE AREA ON FRIDAY. THIS SYSTEM WILL EXIT THE AREA FRIDAY NIGHT WITH ANOTHER LOW MOVING TOWARDS THE PACIFIC COAST ON SATURDAY. THIS LOW IS CURRENTLY FORECAST TO TRACK SOUTH OF THE CWA TOWARDS THE NORTHERN CALIFORNIA COAST THROUGH THE WEEKEND. THIS WILL ALLOW FOR MORE MOISTURE AND INSTABILITY TO BE SPUN UP OVER THE AREA...PROVIDING ANOTHER CHANCE FOR THUNDERSTORMS. THE LOW IS EXPECTED TO SLOWLY MOVE INLAND AND BE CENTERED OVER THE CA/NV BOARDER ON MONDAY NIGHT. OVERALL THE AIRMASS SHOULD BE FAIRLY WARM OVER THE AREA...KEEPING THE TEMPERATURES NEAR TO ABOVE NORMAL. REASONABLE CLOUD COVER CAN BE EXPECTED AT NIGHT AS WELL...ALLOWING FOR MILD NIGHTTIME LOWS. WEBER && .AVIATION...PREVIOUS DISCUSSION...18Z TAFS...MVFR-VFR CONDITIONS OVER THE NEXT 6 HOURS...WITH BETTER CHANCES OF MVFR CONDITIONS OVER THE 0Z-12Z WEDNESDAY TIME PERIOD. DEFORMATION BAND EXPECTED TO SET UP OVER SOUTHERN WASHINGTON DURING THIS PERIOD. THIS COULD ALLOW FOR PERIODS OF MODERATE RAIN...WITH CIGS POSSIBLY FALLING TO IFR CATEGORIES. FOR NOW PROB30 GROUPS COVER THE PERIODS OF CONCERN. POSSIBLE -TSRA AT KPDT AND KALW FROM 0Z-3Z THIS AFTERNOON. HAVE ADDED A TEMPO GROUP TO COVER THE THUNDER. WINDS WILL RANGE FROM 5 TO 15 KTS...WITH GUSTS UP TO 25 KTS. WEBER && .PRELIMINARY POINT TEMPS/POPS... PDT 45 62 45 64 / 90 70 10 30 ALW 48 65 46 69 / 90 80 10 30 PSC 51 70 46 70 / 90 80 10 20 YKM 49 68 43 70 / 80 70 40 20 HRI 49 69 44 70 / 80 70 10 30 ELN 47 66 41 70 / 90 80 40 20 RDM 35 60 36 59 / 50 30 30 50 LGD 43 62 41 64 / 100 70 20 30 GCD 41 63 39 65 / 80 20 20 50 DLS 48 65 46 71 / 60 50 30 30 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. && FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT... WWW.WEATHER.GOV/PENDLETON $$ 97/89/89
AREA FORECAST DISCUSSION
NWS PORTLAND
915 PM PDT MON MAY 11 2015 .SYNOPSIS...AN UPPER LOW WILL MOVE INLAND AND ACROSS SOUTHWESTERN OREGON TONIGHT AND TUESDAY. A BAND OF STRATIFORM RAIN ALONG THE COLUMBIA RIVER WILL PINWHEEL SOUTH ALONG THE COAST AND RETURN INLAND ACROSS THE CENTRAL AND SOUTHERN OREGON COAST TUESDAY. THE UPPER LOW WILL GRADUALLY FILL AS IT DRIFTS NORTHEAST TOWARD EASTERN WASHINGTON TUESDAY NIGHT AND WEDNESDAY WITH LIGHT SHOWER ACTIVITY CONTINUING. AT THE SAME TIME...ANOTHER LOW DROPS SOUTH OFF THE PACIFIC NORTHWEST COAST AND SLOWLY MOVES INTO CALIFORNIA DURING THE LATTER PART OF THE WEEK AND NEXT WEEKEND. && .UPDATE...UPPER LOW CENTER ROUGHLY OVER THE SOUTHERN OREGON COAST NEAR PORT ORFORD. THE BULK OF CONVECTION EAST OF THE CASCADES HAS ENDED WITH A COUPLE STRAY CELLS FIRING AT THIS HOUR. 21Z SREF AND 00Z NAM/GFS RUNS ARE KEEPING THE UPPER LOW CENTER JUST THIS SIDE OF THE OR/CA BORDER FOR TONIGHT WHICH IS CLOSER TO WHAT PREVIOUS RUNS OF THE NAM HAD SHOWN. ADDITIONALLY...THE BETTER DYNAMIC LIFT ASSOCIATED WITH THE DIFFLUENT SE QUADRANT OF THE LOW DEVELOPED ABOUT 75 MILES FURTHER EAST THAN WAS PREVIOUSLY EXPECTED. THUS...A BLEND OF THE 00Z NAM...AND TO A LESSER EXTENT...THE 12Z ECMWF SEEMS TO BE A DECENT MIDDLE GROUND WITH REGARD TO HANDLING THE REST OF TONIGHT. AS SUCH...AM FEELING THE PRIMARY DEFORMATION BAND WILL STAY ALONG THE COLUMBIA RIVER WITH THE EASTERLY FLOW ALONG THE NORTHERN PERIPHERY OF THE UPPER CIRCULATION CONTINUING TO STREAM PRECIPITATION OUT TO SEA ACROSS ASTORIA. OVERNIGHT WILL SEE THE FLOW AND DEEPER MOISTURE THEN WRAP BACK SOUTH CLOSER TO THE COAST. THIS STANDS TO LEAVE THE CASCADE WEST SLOPES (NOW IN THE LEE OF THE SYSTEM) ON THE RELATIVELY DRIER SIDE OF THINGS. THE LEADING EDGE OF THE WRAP AROUND MOISTURE THEN CURLS BACK INLAND AROUND NEWPORT/FLORENCE AND PICKS UP A BIT OF UPSLOPE ENHANCEMENT FOR THE MORNING HOURS TOMORROW. DID NOT HAVE ENOUGH CONFIDENCE THEREAFTER TO MAKE CHANGES TO THE FORECAST PACKAGE AS WE WILL NEED TO SEE HOW THIS FIRST PART WORKS OUT. IT SHOULD BE SAID THAT NO ONE MODEL IS REALLY DOING A STELLAR JOB OF FINDING THE CORRECT MIX OF RAIN PLACEMENT WITH RAIN INTENSITY LEAVING THIS FORECAST WITH MODERATE CONFIDENCE AT BEST. UPDATES WILL BE AVAILABLE SHORTLY. /JBONK && .AVIATION...RAIN AND OCCASIONAL MVFR CIG/VIS ARE SPREADING WEST AND SOUTH THIS EVENING WITH THE TREND CONTINUING INTO THE LATE EVENING. EXPECT MORE WIDESPREAD MVFR CONDITIONS TO DEVELOP THROUGH THE OVERNIGHT AND STICK AROUND MUCH OF TUESDAY WITH RAIN. WINDS WILL BE VARIABLE THROUGH THE PERIOD AND GENERALLY REMAIN BELOW 10 KT. KPDX AND APPROACHES...MVFR CIGS DEVELOPING BY 12Z TUESDAY AND STAYING THROUGH TUESDAY. OCCASIONAL MVFR VIS WITH RAIN. BOWEN && .MARINE...HIGH PRESSURE OVER THE NE PACIFIC IS KEEPING CONDITIONS FAIRLY BENIGN. SEAS SHOULD REMAIN AROUND 5 TO 7 FT THROUGH TUESDAY WITH NORTHWESTERLY WINDS STAYING BELOW 20 KT. SEAS WILL BE CHOPPY DUE TO SHORT PERIODS AROUND 8 SECONDS. MADE ONLY MINOR TWEAKS TO THE FORECAST FOR THE EVENING UPDATE. BOWEN A WEAK LOW PRESSURE SYSTEM MOVES THROUGH ON WEDNESDAY...BUILDING SEAS TO AROUND 8 FT...BUT WINDS EXPECTED TO REMAIN BELOW 20 KT. SEAS FALL BACK DOWN TO 5 TO 6 FT BY THE END OF THIS WEEK WITH THE RETURN OF NORTHWESTERLY WINDS AS HIGH PRESSURE BUILDS BACK OVER THE WATERS. -MCCOY && .PREV DISCUSSION... /ISSUED 215 PM PDT MON MAY 11 2015/ SHORT TERM...TONIGHT THROUGH THURSDAY...EARLY-AFTERNOON WATER VAPOR LOOP SHOWS AN UPPER LEVEL LOW CENTERED WEST OF KONP AND SINKING TO THE S. CONSIDERABLE MOISTURE IN WATER VAPOR FOCUSED OVER THE CASCADES. ALSO LOOKS LIKE A SHORT-WAVE ROTATING INTO SOUTH-CENTRAL OREGON...WHICH HAS RESULTED IN THUNDERSTORM ACTIVITY IN SWRN LAKE COUNTY. KRTX DUAL-POL DOPPLER RADAR SHOWS THE BULK OF THE PRECIP ECHOES ALONG THE CENTRAL AND NORTH OREGON CASCADES INTO ERN CLARK AND COWLITZ COUNTIES IN SW WA. 12Z MODEL RUNS AGREE THAT THE UPPER LOW WILL CONTINUE TO DRIFT SOUTH THIS EVENING...THEN MOVE INLAND OVER NW CALIFORNIA BY 12Z TUE. MODELS ALSO SUGGEST THAT PRECIP WILL BECOME MORE ENHANCED LATE THIS AFTERNOON DUE TO SE-S MID-LEVEL FLOW. HOWEVER...MODELS DO NOT SEEM TO AGREE ON QPF. GFS SHOW MUCH MORE RAINFALL TONIGHT THAN THE NAM OR ECMWF. THE NAM PIVOTS THE DEVELOPING DEFORMATION BAND FURTHER N THAN THE GLOBAL MODELS. THE 19Z HRRR RUN HAS THE DEFORMATION BAND DEVELOPING A FEW HOURS LATER THAN THE EARLIER MORNING RUNS INDICATED...AND SETTLING OVER SRN WA DOWN TO ABOUT A KTMK-KSLE-MT. HOOD LINE BY 07Z TUE. HIGH CONFIDENCE IN WETTING RAIN AMOUNTS...ONE-QUARTER INCH OR GREATER...ACROSS PORTIONS OF THE CWA TONIGHT AND TUE MORNING. LOWER CONFIDENCE ON EXACT LOCATION OF THE DEFORMATION BAND. CONVECTIVE CHANCES TODAY DO NOT LOOK ALL THAT IMPRESSIVE. NAM SOUNDINGS FOR KPDX SHOW AN ISOTHERMAL LAYER THIS AFTERNOON BETWEEN 850 AND 700 MB. MODEL SOUNDING FOR A POINT IN THE CASCADES HAS THE SAME GENERAL PROFILE...BUT DOES HAVE AN LI NEAR 0C THIS AFTERNOON. INCREASED POPS IN THE 00-06Z TUE TIME FRAME...ESPECIALLY IN THE CASCADES AND NORTHERN ZONES. THE DEFORMATION ZONE PERSISTS TUE MORNING. THE NAM ROTATES IT ACROSS SW WA TO THE N OREGON COAST BY 18Z TUE...SIMILAR TO THE ECMWF. IT FINALLY BREAKS UP TUE AFTERNOON. THE MODELS SHOW A DECENT AMOUNT OF CYCLONIC LOW LEVEL ONSHORE FLOW DEVELOPING BELOW THIS BAND AS WELL. CASCADE MODEL SOUNDINGS SUGGEST A LIT MORE SUPPORT FOR CONVECTION TUE AFTERNOON. NAM SOUNDING GIVES 200-250 J/KG CAPE 00Z WED...WHILE THE GFS HAS NEAR-ZERO LI VALUES. THE REMAINS OF THE UPPER LOW LIFT OUT INTO SE WASHINGTON TUE NIGHT AND INTO NE WA BY WED AFTERNOON. ANY REMAINING DEFORMATION WILL LINGER OVER THE S WA CASCADES WED MORNING AND HAVE THE HIGHEST POPS THERE. DECIDED TO INCLUDE A MENTION OF THUNDERSTORMS FOR THE CENTRAL AND N OREGON CASCADES BEGINNING WED AFTERNOON. MODEL SOUNDINGS SHOW A DEFINITE CAP AROUND 700 MB WED MORNING...BUT BY 21Z THE CAP IS GONE WITH CAPE OVER 100 J/KG. AT 00Z THU MODEL CAPE HAS INCREASED TO NEARLY 300 J/KG WITH LI -1C. THINK THE S WA CASCADES WILL HAVE TOO MUCH CLOUD COVER AS THE DEFORMATION BAND SLOWLY DRIFTS N. MUCH MORE IMPRESSIVE CONVECTIVE ENVIRONMENT POSSIBLE THU. PRIMARY UPPER LOW SETTLES OFF THE N CALIFORNIA COAST THU AFTERNOON...WHICH SETS UP UNSTABLE SE-S FLOW OVER THE FORECAST AREA. NAM SOUNDING NEAR SANTIAM PASS HAS NEARLY 550 J/KG CAPE WITH AN LI OF -2C 00Z FRI. GFS EVEN MORE IMPRESSIVE WITH CONVECTIVE PARAMETERS THU. WEISHAAR LONG TERM...THURSDAY NIGHT THROUGH SUNDAY...BY THURSDAY NIGHT A BROAD UPPER LOW PRESSURE WILL CONTINUE A GENERAL TRACK SOUTHWARD ALONG THE CALIFORNIA COAST. MODEL GUIDANCE THIS AFTERNOON IS COMING INTO GOOD AGREEMENT WITH THE GENERAL PATTERN AND EXPECT SHOWERS LINGERING THURSDAY NIGHT AND ALSO ON FRIDAY...WITH THE BEST CHANCES TOWARDS THE CASCADES. MIGHT ALSO BE ENOUGH INSTABILITY TO GET A FEW THUNDERSTORMS NEAR THE CASCADES FROM MT HOOD SOUTHWARD ON FRIDAY. THIS UPPER LOW CONTINUES EASTWARD WITH THE NEXT UPPER LOW PRESSURE SYSTEM MOVING TOWARDS THE REGION OVER THE WEEKEND...MAINTAINING ONSHORE FLOW ALOFT AND THE POTENTIAL FOR CONTINUING SHOWERS THIS WEEKEND. OVERALL...NOT MUCH CHANGE TO THE OVERALL PATTERN THROUGH THE EXTENDED PERIOD WITH TEMPERATURES NEAR SEASONAL NORMS AND SHOWER CHANCES CONTINUING. CULLEN && .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
1136 AM EDT TUE MAY 12 2015 .SYNOPSIS... OUR RECENT STRING OF WARM DAYS AND MILD NIGHTS WILL BE CUT TODAY AS A STRONG COLD FRONT PUSHES EAST ACROSS THE STATE. COOLER... DRIER AND WINDY CONDITIONS WILL ARRIVE DURING THE DAYLIGHT HOURS TODAY...AND LAST THROUGH WEDNESDAY NIGHT. A LARGE AREA OF HIGH PRESSURE WILL BECOME CENTERED OVER THE STATE WEDNESDAY NIGHT AND EARLY THURSDAY. AS THE HIGH DRIFTS EAST AND OFF THE MID ATLANTIC COAST...MILDER CONDITIONS WILL RETURN FOR THURSDAY AND FRIDAY AND CONTINUE THIS WEEKEND AS ANOTHER UPPER RIDGE BUILDS ACROSS THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD FRONT TRACKING ACROSS CENTRAL PA LATE THIS MORNING... DELINEATED BY LINE OF SHALLOW CONVECTION. KBFD JUST HAD A PEAK WIND OF 32 KTS AS THIS BAND MOVED ACROSS...IN LINE WITH PREVIOUS EXPECTATIONS. HI RES HRRR AND 4KM SPC WRF AND MODEL SOUNDINGS INDICATE A RIBBON OF A FEW TO SEVERAL HUNDRED J/KG AVAILABLE FOR SHALLOW CONVECTION TO ACCOMPANY ITS PASSAGE ACROSS MOST OF CENTRAL PA. HI RES SIMULATIONS DAMPEN CONVECTION OVER THE LOWER SUSQ LATER TODAY DUE TO INCREASING DOWNSLOPE COMPONENT...BUT WE`LL LIKELY SEE SOME GUSTY SHOWERS WITH ISOLATED THUNDER FOR MUCH OF THE EARLY AFTERNOON AS THE FRONT SLIDES EAST. STRONG COLD ADVECTION AND 30-40 KT 850 MB WINDS WILL INCREASINGLY MIX BY THIS AFTERNOON BEHIND THE FRONT...WITH FREQUENT GUSTS OF 30+ MPH REACHING THE SFC. HIGH TEMPS WILL RANGE FROM THE COOLISH M-U60S NW...TO THE LOWER AND MID 80S IN THE SOUTHEAST /WHICH WILL BE ABOUT 10-12 DEG ABOVE NORMAL FOR TODAY IN THE GREATER HARRISBURG...YORK...LANCASTER AREA/. EXTENSIVE...COLD AIR STRATO CU WILL SPREAD INTO THE WEST THIS AFTERNOON...BUT BREAK UP AND FLATTEN OUT IN THE LLVL DOWNSLOPE AND ADIABATIC WARMING/DRYING REGIME ACROSS THE CENTRAL VALLEYS AND SUSQ REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... DEEPENING NW FLOW...WITH SHALLOW COLD AIR AT LLVLS WILL LEAD TO GENERALLY PARTLY SKIES ACROSS THE SUSQ VALLEY....WITH MOSTLY CLOUD TO CLOUDY CONDITIONS OVER THE MW MTNS. THIS CLOUD DISTRIBUTION WILL HELP TO LESSEN THE NORMAL STRONG NW/SE DIFF IN MIN TEMPS ACROSS THE STATE. LOWS EARLY TUESDAY WILL BE IN THE UPPER 30S TO LOW 40S WEST...AND IN THE U40S TO LOWER 50S THROUGHOUT THE SUSQEHANNA VALLEY && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... LATER SHIFTS WILL NEED TO MONITOR THE THREAT FOR FROST OR FREEZE PRODUCTS WED NIGHT AS TEMPS WILL BE PLUMMETING INTO THE U20S/L30S INVOF KBFD...AND MID 30S TO AROUND 40F AS YOU HEAD SE FROM THE I99/RT200 CORRIDOR TWD INTERSTATE 81. LOWS ACROSS THE LOWER SUSQ VALLEY SHOULD BE AOA 40F EARLY THURSDAY. A FEW WEAK SYSTEMS CRESTING THE MEAN EASTERN U.S. UPPER RIDGE AND DROPPING SE FROM THE GLAKES WILL BRING THE CHC OF SOME SHOWERS FRIDAY AFTERNOON THROUGH SAT. UPPER RIDGE SHARPENS OVER THE MID ATLANTIC REGION SAT NIGHT INTO SUNDAY. WASHED OUT FRONT TO THE SOUTH OF THE STATE SAT NIGHT WILL LIKELY RETURN NORTH AS A WARM FRONT SUNDAY...BRINGING BACK THE CHC FOR SHOWERS/SCTD TSRA SUNDAY AFTERNOON INTO EARLY NEXT WEEK AHEAD OF A STRONGER SYSTEM THAT WILL BE GRADUALLY SHEARING OUT AS IT HEADS NE TWD THE GLAKES REGION. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... COLD FRONT AND NARROW BAND OF MVFR CIGS/SHRA WITH SFC WND G35 KTS SPREADING ACROSS NORTHERN AND CENTRAL AIRFIELDS. ASSOC DRIER AIR WILL CAUSE CIGS TO BECOME VFR...EVEN OVR THE W MTNS THIS AFTERNOON. WIDESPREAD VFR CONDS EXPECTED FOR THE BALANCE OF THE DAY...AS DRIER AIR FLOWS IN BEHIND COLD FRONT. MAIN CONCERN LATER TODAY WILL BE THE GUSTY WEST WINDS...RESULTING FROM TIGHT PRESSURE GRADIENT SOUTH OF LOW PRES OVR S QUEBEC. MDL SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS BY THIS AFTN. THE STRONGEST GUSTS WILL DIMINISH AFTER SUNSET...BUT IT WILL REMAIN BREEZY OVERNIGHT. OUTLOOK... WED...NO SIG WX EXPECTED. THU...EARLY AM FOG POSS NW MTNS. FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS. SAT...SCT PM TSRA IMPACTS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...DEVOIR/LAMBERT SHORT TERM...LAMBERT LONG TERM...LAMBERT AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
613 AM EDT TUE MAY 12 2015 .SYNOPSIS... OUR RECENT STRING OF WARM DAYS AND MILD NIGHTS WILL BE CUT TODAY AS A STRONG COLD FRONT PUSHES EAST ACROSS THE STATE. COOLER... DRIER AND WINDY CONDITIONS WILL ARRIVE DURING THE DAYLIGHT HOURS TODAY...AND LAST THROUGH WEDNESDAY NIGHT. A LARGE AREA OF HIGH PRESSURE WILL BECOME CENTERED OVER THE STATE WEDNESDAY NIGHT AND EARLY THURSDAY. AS THE HIGH DRIFTS EAST AND OFF THE MID ATLANTIC COAST...MILDER CONDITIONS WILL RETURN FOR THURSDAY AND FRIDAY AND CONTINUE THIS WEEKEND AS ANOTHER UPPER RIDGE BUILDS ACROSS THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SFC-850 MB NORTH/SOUTH THETA-E RIDGE WAS SLIDING INTO THE EASTERN HALF OF THE STATE AT 09Z...WITH JUST A FEW BRIEF SHOWERS OR SPRINKLES RACING ENE. SFC DEWPOINTS DROPPING OFF BY SEVERAL DEG F ACROSS WESTERN PENN /TO THE WEST OF RT 219/...AND THIS MARKS THE WEAK...INITIAL COLD FRONT THAT WILL SLIDE ACROSS MUCH OF THE FCST AREA BY 12Z. COLD FRONT JUST PUSHED THROUGH KTOL OVER THE PAST HOUR...AND WE/LL HAVE TO CONTENT WITH THIS WEATHER FEATURE DURING THE LATE MORNING /WEST/ AND AFTERNOON HOURS /EAST/. WELL DEFINED DRY SLOT WITHIN 50 MILES WITHER SIDE OF THE FRONT...WILL BE PUSHING OVER THE CWA LATE THIS MORNING /WEST/ AND DURING THE AFTERNOON /EAST/. TEMPS WILL CLIMB ONLY ABOUT 5-7 DEG ACROSS THE ALLEGHENIES OF NW PENN TODAY...WHILE THE CENTRAL AND SE VALLEYS SEE A TEMP INCREASE OF 13 TO 15F TODAY. HIGH TEMPS RANGING FROM THE U60S NW...TO THE MID 80S IN THE SOUTHEAST WILL BE ABOUT 10-12 DEG ABOVE NORMAL FOR TODAY. EXTENSIVE...COLD AIR STRATO CU WILL SPREAD INTO THE THIS AFTERNOON...BUT BREAK UP AND FLATTEN OUT IN THE LLVL DOWNSLOPE AND ADIABATIC WARMING/DRYING REGIME ACROSS THE CENTRAL VALLEYS AND SUSQ REGION. IN ADDITION...LATEST MODEL FORECAST SOUNDINGS INDICATE MODERATE MIXING POTENTIAL WITH MANY AREAS SEEING WIND GUSTS IN THE 30-35 MPH RANGE /OR SLIGHTLY HIGHER/. EXPECT HIGHER TERRAIN OF THE NORTH AND WEST TO SEE SCT -SHRA...WHILE CENTRAL AND SOUTHEAST AREAS REMAIN PARTLY SUNNY AND DRY. HIGHS WILL RANGE FROM JUST 60 TO 65F ACROSS THE NORTHWEST MTNS...TO THE LOWER 80S THROUGHOUT THE LOWER SUSQ RIVER VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... DEEPENING NW FLOW...WITH SHALLOW COLD AIR AT LLVLS WILL LEAD TO GENERALLY PARTLY SKIES ACROSS THE SUSQ VALLEY....WITH MOSTLY CLOUD TO CLOUDY CONDITIONS OVER THE MW MTNS. THIS CLOUD DISTRIBUTION WILL HELP TO LESSEN THE NORMAL STRONG DIFF IN MIN TEMPS ACROSS CENTRAL PENN AND THE SUSQ VALLEY. LOWS EARLY TUESDAY WILL BE IN THE UPPER 30S TO LOW 40S WEST...AND IN THE U40S TO LOWER 50S THROUGHOUT THE SUSQEHANNA VALLEY && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... LATER SHIFTS WILL NEED TO MONITOR THE THREAT FOR FROST OR FREEZE PRODUCTS WED NIGHT AS TEMPS WILL BE PLUMMETING INTO THE U20S/L30S INVOF KBFD...AND MID 30S TO AROUND 40F AS YOU HEAD SE FROM THE I99/RT200 CORRIDOR TWD INTERSTATE 81. LOWS ACROSS THE LOWER SUSQ VALLEY SHOULD BE AOA 40F EARLY THURSDAY. A FEW WEAK SYSTEMS CRESTING THE MEAN EASTERN U.S. UPPER RIDGE AND DROPPING SE FROM THE GLAKES WILL BRING THE CHC OF SOME SHOWERS FRIDAY AFTERNOON THROUGH SAT. UPPER RIDGE SHARPENS OVER THE MID ATLANTIC REGION SAT NIGHT INTO SUNDAY. WASHED OUT FRONT TO THE SOUTH OF THE STATE SAT NIGHT WILL LIKELY RETURN NORTH AS A WARM FRONT SUNDAY...BRINGING BACK THE CHC FOR SHOWERS/SCTD TSRA SUNDAY AFTERNOON INTO EARLY NEXT WEEK AHEAD OF A STRONGER SYSTEM THAT WILL BE GRADUALLY SHEARING OUT AS IT HEADS NE TWD THE GLAKES REGION. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... RADAR AT 06Z SHOWS ONE LINE OF SHRA/TSRA PUSHING THRU EASTERN PA AND ANOTHER BATCH OF SHRA ASSOC WITH APPROACHING COLD FRONT OVER WESTERN PA. FOR MUCH OF CENTRAL PA...NO SIG CIG/VIS REDUCTIONS ARE EXPECTED EARLY THIS MORNING. THE EXCEPTION COULD BE KBFD AND KJST...WHERE A BRIEF PERIOD OF IFR CIGS MAY DEVELOP AS PLUME OF MOIST AIR ALONG COLD FRONT ASCENDS THE W MTNS. MDL RH TIMESECTIONS AND HRRR OUTPUT SUGGEST THE WINDOW OF OPPORTUNITY FOR IFR CONDS AT KBFD/KJST WILL BE 09Z-11Z. AFTER 11Z...DRIER AIR WILL ARRIVE ON WEST WIND...CAUSING IMPROVING CONDS. WIDESPREAD VFR CONDS EXPECTED AFTER SUNRISE...AS DRIER AIR FLOWS IN BEHIND COLD FRONT. MAIN CONCERN TODAY WILL BE THE GUSTY WEST WINDS...RESULTING FROM TIGHT PRESSURE GRADIENT SOUTH OF LOW PRES OVR S QUEBEC. MDL SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS BY THIS AFTN. THE STRONGEST GUSTS WILL DIMINISH AFTER SUNSET...BUT IT WILL REMAIN BREEZY OVERNIGHT. OUTLOOK... WED...NO SIG WX EXPECTED. THU...EARLY AM FOG POSS NW MTNS. FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS. SAT...SCT PM TSRA IMPACTS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...LAMBERT/MARTIN AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
346 AM EDT TUE MAY 12 2015 .SYNOPSIS... SUMMERTIME WARMTH AND HUMIDITY WILL COME TO AN END TODAY AS A VIGOROUS UPPER TROF AND ASSOCIATED COLD FRONT CROSSES THE REGION. COOLER...DRIER AND WINDY CONDITIONS WILL ARRIVE DURING THE DAYLIGHT HOURS TUESDAY...AND LAST THROUGH WEDNESDAY NIGHT. MILDER CONDITIONS WILL RETURN FOR THURSDAY AND FRIDAY AND CONTINUE THIS WEEKEND AS ANOTHER UPPER RIDGE BUILDS ACROSS THE REGION. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... SFC-850 MB NORTH/SOUTH THETA-E RIDGE WAS SLICING RIGHT THROUGH CENTRAL PENN AT 07Z WITH JUST SOME ISOLATED-SCATTERED SHOWERS RACING QUCIKLY TO THE ENE. SFC DEWPOINTS DROPPING OFF BY SEVERAL DEG F ALONG THE PENN/OHIO BORDER ATTM /MARKING THE WEAK...INITIAL COLD FRONT THAT WILL SLIDE ACROSS MUCH OF THE FCST AREA BY 12Z. TEMPS WILL STAY MILD FOR THE REST OF THE NIGHT AND IT WILL FEEL MUGGY WITH TEMPS AND DEWPOINTS IN THE L-M 60S /EXCEPT U50S INVOF KBFD/. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... INITIAL CFRONT CLEARS OUR FAR EASTERN COUNTIES DURING THE MID MORNING HOURS TODAY...FOLLOWED BY WINDY AND DRIER CONDITIONS IN STORE FOR MOST OF THE REGION. MODEL FORECAST SOUNDINGS INDICATE MODERATE MIXING POTENTIAL WITH MANY AREAS SEEING 30-35 MPH GUSTS OR HIGHER. EXPECT HIGHER TERRAIN OF THE NORTH AND WEST TO SEE SCT -SHRA...WHILE CENTRAL AND SOUTHEAST AREAS REMAIN PARTLY SUNNY AND DRY. HIGHS WILL RANGE FROM JUST 60 TO 65F ACROSS THE NORTHWEST MTNS...TO THE LOWER 80S THROUGHOUT THE LOWER SUSQ RIVER VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STILL LOOKING AT A FEW SHOWERS ACROSS THE NORTH TUESDAY NIGHT INTO WED...WITH THE COLD AIR ALOFT. IT WILL BE BREEZY AND COLDER FROM LATE TUE INTO THU MORNING. LATER SHIFTS WILL NEED TO MONITOR THE NEED FOR FROST AND FREEZE PRODUCTS. MID SHIFT INSERTED SHOWERS INTO THE FCST FOR FRIDAY INTO SAT. THIS BASED ON WEAK SYSTEM DROPPING SE. WHILE MOISTURE MAY BE LIMITED...DIRECTIONAL SHEAR WILL BE THERE. I DID CUT BACK ON THE SHOWERS SOME ON THE FIRST PART OF FRIDAY. DID ADJUST POPS SOME FOR SUNDAY...AS SYSTEM DROPS SE OF OUR AREA...DID CUT BACK SOME. FOR MONDAY...ADJUSTED POPS SOME MORE...AS WE WILL BE ON THE EASTERN AND NORTHERN EDGE OF THE WARM ADVECTION. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... RADAR AT 06Z SHOWS ONE LINE OF SHRA/TSRA PUSHING THRU EASTERN PA AND ANOTHER BATCH OF SHRA ASSOC WITH APPROACHING COLD FRONT OVER WESTERN PA. FOR MUCH OF CENTRAL PA...NO SIG CIG/VIS REDUCTIONS ARE EXPECTED EARLY THIS MORNING. THE EXCEPTION COULD BE KBFD AND KJST...WHERE A BRIEF PERIOD OF IFR CIGS MAY DEVELOP AS PLUME OF MOIST AIR ALONG COLD FRONT ASCENDS THE W MTNS. MDL RH TIMESECTIONS AND HRRR OUTPUT SUGGEST THE WINDOW OF OPPORTUNITY FOR IFR CONDS AT KBFD/KJST WILL BE 09Z-11Z. AFTER 11Z...DRIER AIR WILL ARRIVE ON WEST WIND...CAUSING IMPROVING CONDS. WIDESPREAD VFR CONDS EXPECTED AFTER SUNRISE...AS DRIER AIR FLOWS IN BEHIND COLD FRONT. MAIN CONCERN TODAY WILL BE THE GUSTY WEST WINDS...RESULTING FROM TIGHT PRESSURE GRADIENT SOUTH OF LOW PRES OVR S QUEBEC. MDL SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS BY THIS AFTN. THE STRONGEST GUSTS WILL DIMINISH AFTER SUNSET...BUT IT WILL REMAIN BREEZY OVERNIGHT. OUTLOOK... WED...NO SIG WX EXPECTED. THU...EARLY AM FOG POSS NW MTNS. FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS. SAT...SCT PM TSRA IMPACTS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/LAMBERT NEAR TERM...DANGELO/LAMBERT SHORT TERM...DEVOIR LONG TERM...MARTIN AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
237 AM EDT TUE MAY 12 2015 .SYNOPSIS... SUMMERTIME WARMTH AND HUMIDITY WILL COME TO AN END LATE TONIGHT AND TUESDAY AS A VIGOROUS UPPER TROF AND ASSOCIATED COLD FRONT CROSSES THE REGION. COOLER...DRIER AND WINDY CONDITIONS WILL ARRIVE DURING THE DAYLIGHT HOURS TUESDAY...AND LAST THROUGH WEDNESDAY NIGHT. MILDER CONDITIONS WILL RETURN FOR THURSDAY AND FRIDAY AND CONTINUE THIS WEEKEND AS ANOTHER UPPER RIDGE BUILDS ACROSS THE REGION. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... COLD POOL FROM THE STORMS OVER OH AND WRN PA HAVE MADE QUITE AN ACTIVE EVENING AS IT FORMED INTO A NICE BOW ECHO. MANY DAMAGE REPORTS WITH TREES NOW PRETTY MUCH LEAFED OUT EVERYWHERE. MESO MDLS CONTINUE TO MAKE NO PRECIP TO THE SE OF AOO/UNV/IPT OVERNIGHT. BUT ALLOWING FOR SOME CONTINUATION IN THE LINE OF SHOWERS AS IT IS...BUT BUYING INTO THE WEAKENING/DISSIPATION A LITTLE MORE AS THE LATEST ECHOES PLAY THAT THE GUST FRONT IS RACING TOO FAR AHEAD OF THE SRN CELLS. THIS BODES WELL FOR WEAKENING THERE. LEFT IN JUST A 30 POP FOR AN HR OR TWO FOR THE SERN COS. COLD AIR SEEMS LIKE IT COMES IN TWO WAVES...WITH THE FIRST SURGE LATER TONIGHT BEING ACCOMPANIED BY MORE SHOWERS...MAINLY ACROSS THE NW MTNS. A SECONDARY FRONT IN THE MORNING WILL ALSO MAKE A FEW SHRA. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... FRONT CLEARS SOUTHEASTERN COUNTIES EARLY TUESDAY...WITH WINDY AND DRIER CONDITIONS IN STORE FOR MOST OF THE REGION. MODEL FORECAST SOUNDINGS INDICATE MODERATE MIXING POTENTIAL WITH MANY AREAS SEEING 30-35 MPH GUSTS OR HIGHER. EXPECT HIGHER TERRAIN OF THE NORTH AND WEST TO SEE SCT -SHRA...WHILE CENTRAL AND SOUTHEAST AREAS REMAIN PARTLY SUNNY AND DRY. HIGHS WILL RANGE FROM THE UPPER 60S NORTHWEST TO THE LOWER 80S LOWER SUSQ RIVER VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STILL LOOKING AT A FEW SHOWERS ACROSS THE NORTH TUESDAY NIGHT INTO WED...WITH THE COLD AIR ALOFT. IT WILL BE BREEZY AND COLDER FROM LATE TUE INTO THU MORNING. LATER SHIFTS WILL NEED TO MONITOR THE NEED FOR FROST AND FREEZE PRODUCTS. MID SHIFT INSERTED SHOWERS INTO THE FCST FOR FRIDAY INTO SAT. THIS BASED ON WEAK SYSTEM DROPPING SE. WHILE MOISTURE MAY BE LIMITED...DIRECTIONAL SHEAR WILL BE THERE. I DID CUT BACK ON THE SHOWERS SOME ON THE FIRST PART OF FRIDAY. DID ADJUST POPS SOME FOR SUNDAY...AS SYSTEM DROPS SE OF OUR AREA...DID CUT BACK SOME. FOR MONDAY...ADJUSTED POPS SOME MORE...AS WE WILL BE ON THE EASTERN AND NORTHERN EDGE OF THE WARM ADVECTION. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... RADAR AT 06Z SHOWS ONE LINE OF SHRA/TSRA PUSHING THRU EASTERN PA AND ANOTHER BATCH OF SHRA ASSOC WITH APPROACHING COLD FRONT OVER WESTERN PA. FOR MUCH OF CENTRAL PA...NO SIG CIG/VIS REDUCTIONS ARE EXPECTED EARLY THIS MORNING. THE EXCEPTION COULD BE KBFD AND KJST...WHERE A BRIEF PERIOD OF IFR CIGS MAY DEVELOP AS PLUME OF MOIST AIR ALONG COLD FRONT ASCENDS THE W MTNS. MDL RH TIMESECTIONS AND HRRR OUTPUT SUGGEST THE WINDOW OF OPPORTUNITY FOR IFR CONDS AT KBFD/KJST WILL BE 09Z-11Z. AFTER 11Z...DRIER AIR WILL ARRIVE ON WEST WIND...CAUSING IMPROVING CONDS. WIDESPREAD VFR CONDS EXPECTED AFTER SUNRISE...AS DRIER AIR FLOWS IN BEHIND COLD FRONT. MAIN CONCERN TODAY WILL BE THE GUSTY WEST WINDS...RESULTING FROM TIGHT PRESSURE GRADIENT SOUTH OF LOW PRES OVR S QUEBEC. MDL SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS BY THIS AFTN. THE STRONGEST GUSTS WILL DIMINISH AFTER SUNSET...BUT IT WILL REMAIN BREEZY OVERNIGHT. OUTLOOK... WED...NO SIG WX EXPECTED. THU...EARLY AM FOG POSS NW MTNS. FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS. SAT...SCT PM TSRA IMPACTS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR NEAR TERM...DANGELO SHORT TERM...DEVOIR LONG TERM...MARTIN AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
136 PM EDT TUE MAY 12 2015 .SYNOPSIS... A WEAK COLD FRONT WILL CROSS OUR AREA TODAY...BEFORE STRONG HIGH PRESSURE BUILDS IN FROM THE NORTH AND REMAINS THROUGH FRIDAY. MOISTURE WILL SPREAD OVER THE AREA AHEAD OF ANOTHER COLD FRONT THAT APPROACHES FROM THE WEST EARLY NEXT WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 130 PM EDT...RADAR HAS BEEN RELATIVELY QUIET EARLY THIS AFTERNOON AS A COLD FRONT SLIPS SLOWLY EASTWARD ACROSS THE REGION. HOWEVER...THE HRRR CONTINUES TO INSIST ON SCATTERED CONVECTIVE DEVELOPMENT ALONG THE PASSING COLD FRONT...WITH PEAK PIEDMONT COVERAGE CIRCA 19Z TO 20Z. THIS IS SOMEWHAT CONSISTENT WITH SB CAPE VALUES OF 1000 TO 1500 J/KG OR GREATER OVER THE ERN PIEDMONT PARTS OF OUR FORECAST AREA...AND ALSO WITH MODEL PROFILES FINALLY OVERCOMING LOW LEVEL CINH AROUND THAT TIME. HOWEVER...THE MID DECK OF CLOUDS HAS GREATLY LIMITED HEATING FOR MUCH OF THE AREA...SO EXPECT THAT ANY ISOLD TO SCT CONVECTION THAT DOES FORM WILL BE RATHER WEAK. OTHERWISE...THE SFC COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA THIS EVENING WITH DRIER HIGH PRESSURE BUILDING OVER TO THE N THROUGH WED. WEAK CHANNELED VORTICITY WILL SLIDE EAST ACROSS THE AREA OVERNIGHT TO PRODUCE SOME HIGH LEVEL CLOUDINESS...BUT WITH LOWER LEVELS DRY. EXPECT MINS TO FALL INTO THE 40S MTNS AND 50S PIEDMONT UNDER WEAK COLD ADVECTION. HEIGHT RISES WILL DEVELOP FROM THE WEST ON WED WITH COMFORTABLE MAXES NEAR CLIMO. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... AT 300 AM EDT TUESDAY...ON WEDNESDAY MORNING AN UPPER TROUGH WILL BE ALONG THE EAST COAST...WHILE AND UPPER RIDGE WILL EXTEND FROM THE GULF STATES TO THE NORTHERN PLAINS. BY THURSDAY THIS NEGATIVELY TILTED RIDGE WILL EXTEND FROM FL TO THE UPPER MS RIVER VALLEY. A STRONG SHORTWAVE WILL ACROSS THE MS RIVER VALLEY ON THURSDAY... WEAKENING AS IT MOVES THROUGH THE RIDGE AXIS ON THURSDAY NIGHT. AT THE SURFACE...ON WEDNESDAY DRY HIGH PRESSURE CENTERED OVER THE GREAT LAKES WILL BUILD SOUTH ACROSS OUR AREA IN THE WAKE OF A DEPARTING COLD FRONT. AS THE HIGH MOVES EAST ON THURSDAY...IT EXTENDS SOUTH ALONG THE EAST SLOPES OF THE APPALACHIANS. ON THURSDAY NIGHT...ISENTROPIC UPGLIDE OVER THE HIGH SETS THE STAGE FOR PRECIPITATION...MAINLY OVER THE MOUNTAINS. TEMPERATURES WILL START OUT SLIGHTLY ABOVE NORMAL IN DOWNSLOPE WARMING BEHIND THE FRONT...FALLING TO NEAR NORMAL AS THE COOLER AIR MASS ARRIVES AND LOW LEVEL FLOW VEERS TO NE. && .LONG TERM /FRIDAY THROUGH MONDAY/... AT 135 PM EDT TUESDAY...HIGH CONFIDENCE IS HAD THROUGHOUT THE EXT PERIOD. GOOD INDIVIDUAL RUN TO RUN AND MODEL TO MODEL CONSISTENCY CONTINUES TO INDICATE A BUILDING H5 RIDGE SAT BECOMING REINFORCED ON SUN...THEN SLOWLY BREAKING DOWN MON THROUGH TUE. THERE ARE SOME SUBTLE DIFFERENCES IN IN THE MAGNITUDE AND LOCATION OF THE RIDGE AXIS...HOWEVER NOT ENOUGH DIFFERENCES TO IMPACT THE SENSIBLE WX SIGFNTLY. AT THE SFC...THE MAIN SYNOPTIC FEATURE WILL BE A MID ATL HIGH MERGING WITH THE BERMUDA HIGH CREATING A DOMINATE RIDGING PATTERN ACROSS THE CWFA THROUGH MOST OF THE PERIOD. THIS SETUP WILL KEEP THE MAIN STORM ACTIVITY AND HIGHER DEEP LAYERED INSTABILITY WEST OF THE AREA SAT AND SUN...WITH ISOL/SCT PULSE MTN TSTMS PROBABLE EACH AFTERNOON. THE SFC RIDGE WEAKENS ON MON WHICH WILL ALLOW HIGHER TD/S NORTH AND INCREASE SBCAPE VALUES...ENUF SO FOR MENTION OF DIURNAL THUNDER ACROSS ALL ZONES. WITH LIMITED ULVL ENERGY...THE ATMOS WILL BE IN A TYPICAL SUMMERTIME PATTERN WITH SCT PULSE SEVERE STORMS POSSIBLE EACH AFTERNOON MON/TUE. WITH CONTINUED RIDGING AND SW/LY LLVL FLOW...MAX TEMPS WILL BEGIN RIGHT AROUND NORMAL SAT AND INCREASE TO A COUPLE CATS ABOVE NORMAL BY TUE. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AT KCLT...MID CLOUDS THROUGH MIDDAY HAVE LIMITED HEATING AND INSTABILITY. WILL THUS CONTINUE TO FEATURE ONLY VCSH WITH THE FROPA THIS AFTN. OTHERWISE...EXPECT WSW WINDS TO TOGGLE NW WITH FROPA TOWARD EVENING AND THEN TURN NRLY AND NE OVERNIGHT INTO WED MORNING. ANY CIGS SHOULD BE MID AND HIGH CLOUDS...WITH HIGHER CLOUDS THINNING LATER IN THE PERIOD. ELSEWHERE...MORNING MID CLOUDS HAVE LIMITED INSTABILITY...WHICH SHOULD KEEP FOOTHILL TAFS DRY THIS AFTN. THE FROPA IS THROUGH KAVL...SO DRY AND VFR CONDITIONS WILL CONTINUE THERE AS WELL...WITH OCNL NW GUSTS. FOOTHILL WINDS WILL TOGGLE NW THROUGH LATE AFTN AND NRLY THEN NE OVERNIGHT THROUGH WED MORNING. LITTLE MORE THAN HIGH CLOUDS ARE THEN EXPECTED THE LATER HALF OF THE PERIOD. OUTLOOK...DRIER AIR WILL SETTLE IN UNDER BUILDING HIGH PRESSURE THROUGH THU. RETURN FLOW MOISTURE AROUND THE HIGH PRESSURE MAY ALLOW DIURNAL SHOWERS AND THUNDERSTORMS TO RETURN TO THE AREA FRIDAY THROUGH THE WEEKEND...ESPECIALLY OVER THE MTNS. CONFIDENCE TABLE... 17-23Z 23-05Z 05-11Z 11-12Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 100% 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...JAT NEAR TERM...HG SHORT TERM...JAT LONG TERM...JAT AVIATION...HG
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1112 AM MDT TUE MAY 12 2015 .UPDATE... ISSUED AT 938 AM MDT TUE MAY 12 2015 15Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM NORTHWEST WY INTO SOUTHWEST SD. LIFT UNDER RIGHT ENTRANCE REGION OF JET STREAK ACROSS THE NORTHERN PLAINS ASSISTING SOME WEAKER RETURNS ON RADAR ACROSS FAR NORTHEAST WY/SOUTHEAST MT/ENTERING NORTHWEST SD. MOST OF IT NOT REACHING THE GROUND...AND LOOKING AT THE 12Z KUNR SOUNDING THERE IS SOME DRY AIR TO OVERCOME. 12Z RAP SHOWS A BIT OF SBCAPE OVER THE HIGHER TERRAIN AS DECENT SOUTHERLY FLOW FEEDS MOISTURE POOLING ALONG THE BOUNDARY SO HAVE ADDED SMALL POPS LATER THIS AFTERNOON FOR THOSE AREAS. && .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT ISSUED AT 300 AM MDT TUE MAY 12 2015 WESTERN CONUS UPPER LEVEL TROUGHING ONGOING THIS MORNING WITH A LOCAL WAA RESPONSE. WEAK LEAD IMPULSE FROM THIS SYSTEM WILL SUPPORT INCREASING MID/HIGH CLOUDS THROUGH MORNING ACROSS THE NORTHERN HALF...WITH A FEW SPRINKLES POSSIBLE ACROSS THE FAR NORTH. MEANWHILE ANOTHER UPPER LEVEL IMPULSE WILL SHIFT NE INTO THE SW CONUS AND SOUTHERN PLAINS. THIS SYSTEM WILL HELP SUPPORT DEEPER MOISTURE NORTH INTO THE AREA THROUGH TONIGHT. ONGOING PRESSURE FALLS PER THE ADVANCING WESTERN CONUS UPPER TROUGH WILL SUPPORT A LLJ TONIGHT WITH SOME FORCING FOR ASCENT PER A SLOW MOVING NW CONUS UPPER TROUGH GRAZING THE NORTHERN PLAINS TONIGHT. STEEP MID LEVEL LAPSE RATE WITH AN FGEN RESPONSE AND INCREASING ELEVATED INSTABILITY NOTED IN MU CAPES WILL SUPPORT A SLIGHT CHANCE SHOWER/TS THREAT ACROSS THE NORTHERN HALF TONIGHT. HIRES MODELS INCLUDING THE NAM SUGGEST AN ISOLD HIGH BASED SHRA/TS COULD DEVELOP OVER NE WY THIS EVENING AS CIN IS MINIMIZED PER INSOLATION...WITH ANY ACTIVITY BEING CARRIED NE BY A DEVELOPING LLJ. DID ADJUST SLIGHT CHANCE POPS SW INTO NE WY AND THE BH AFTER 00Z THIS EVENING FOR THIS...WITH A SLIGHTLY EARLIER START TIME POSSIBLE. LEE SIDE TROUGH WILL SHIFT EAST ACROSS THE FA WED MORNING AND STALL WITH THE SOUTHERN PLAINS IMPULSE SHIFTING NORTH. RENEWED FGEN FROM THIS SYSTEM WILL SUPPORT INCREASING LL CONVERGENCE ALONG AND NEAR THE SFC TROUGH WHICH WILL BE SOMEWHERE ACROSS THE EASTERN FA. INCREASING LL MOISTURE COMBINED WITH DIURNAL INSTABILITY WILL ALLOW INCREASING CHANCES FOR SHRA/TS THERE...WITH OTHER ACTIVITY POSSIBLE OVER THE BH AND NE WY PER DIURNAL HEATING IN THE PRESENCE OF UNSTABLE PROFILES/WEAK CIN. SHRA/TS CHANCES SHOULD INCREASE WED NIGHT AS THE LLJ SUSTAINED WITH ONGOING MOISTURE TRANSPORT AND INCREASING LSA FROM THE EXPECTED IMPULSE. BULK OF FORCING FROM THIS SYSTEM WILL REMAIN SE OF THE FA...INCLUDING THE ASSOCIATED PRECIP CHANCES. HAVE RETAINED HIGH CHANCE POPS...PRECLUDING LIKELY ATTM GIVEN CONVECTIVE COMPONENT TO PRECIP. AS FOR TEMPS...BUMPED HIGHS UP BOTH TODAY AND WED. SNOW PACK HAS ERODED QUITE WELL OVER MUCH OF THE AREA...WITH THE DEEPEST SNOW REMAINING OVER SW SD. STRONG SE WINDS UNDER MAY SUN SHOULD MIX WARMER AIR DOWN WITH NO PROBLEM...THUS HAVE OPTED FOR TEMPS MORE IN LINE WITH GUIDANCE. .LONG TERM...THURSDAY THROUGH MONDAY ISSUED AT 300 AM MDT TUE MAY 12 2015 THE UPPER LEVEL RIDGE WILL MOVE EAST OF THE AREA ON WEDNESDAY. THIS WILL PUT THE AREA IN ACTIVE SOUTHWEST FLOW FOR MID WEEK INTO THE WEEKEND...WITH DAILY CHANCES FOR RAIN SHOWERS AND SOME THUNDERSTORMS. A FAST-MOVING SHORTWAVE WILL SWEEP THROUGH THE CENTRAL CONUS WEDNESDAY NIGHT AND THURSDAY...AND THEN ANOTHER UPPER LOW IS PROGGED TO MOVE ACROSS THE ROCKIES AND INTO THE PLAINS THIS WEEKEND...BRINGING THE BEST CHANCES FOR ADDITIONAL RAINFALL. MODELS ARE INDICATING AROUND A HALF INCH OF QPF BY THE END OF THE WEEK...WITH AN ADDITIONAL INCH OR TWO DURING THE WEEKEND. AS FAR AS TEMPERATURES GO...MORE SPRING LIKE READINGS ARE EXPECTED FROM MID WEEK THROUGH THE WEEKEND. THEREFORE...THE PRECIPITATION SHOULD REMAIN RAIN. && .AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY ISSUED AT 1110 AM MDT TUE MAY 12 2015 GUSTY SOUTHERLY WINDS ACROSS SOUTH CENTRAL SD WILL DIMINISH THIS EVENING. NORTHWEST SD INTO NORTHEAST WY AND THE BLACK HILLS HAVE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THIS EVENING AND OVERNIGHT. GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH WEDNESDAY MORNING...ALTHOUGH THERE MAY BE SOME LOCAL MFVR CIGS WITH ANY SHOWERS AND THUNDERSTORMS. MODELS ARE IN DISAGREEMENT ON THE POSSIBLE DEVELOPMENT OF FOG ACROSS NORTHEAST WY AND AREAS JUST EAST OF THE BH. COULD BE SOME LOW STRATUS...BUT WILL KEEP TAFS VFR FOR NOW. && .HYDROLOGY... ISSUED AT 300 AM MDT TUE MAY 12 2015 RUNOFF FROM RAIN AND MELTING SNOW IS CAUSING RAPID RISES IN THE LEVEL OF THE WHITE RIVER BETWEEN INTERIOR AND OACOMA. A FLOOD WARNING HAS BEEN ISSUED FOR THAT AREA AS MINOR TO MODERATE FLOODING IS FORECAST TO DEVELOP STARTING TUESDAY MORNING. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...HELGESON SHORT TERM...JC LONG TERM...7 AVIATION...POJORLIE HYDROLOGY...JC
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
950 AM MDT TUE MAY 12 2015 .UPDATE... ISSUED AT 938 AM MDT TUE MAY 12 2015 15Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM NORTHWEST WY INTO SOUTHWEST SD. LIFT UNDER RIGHT ENTRANCE REGION OF JET STREAK ACROSS THE NORTHERN PLAINS ASSISTING SOME WEAKER RETURNS ON RADAR ACROSS FAR NORTHEAST WY/SOUTHEAST MT/ENTERING NORTHWEST SD. MOST OF IT NOT REACHING THE GROUND...AND LOOKING AT THE 12Z KUNR SOUNDING THERE IS SOME DRY AIR TO OVERCOME. 12Z RAP SHOWS A BIT OF SBCAPE OVER THE HIGHER TERRAIN AS DECENT SOUTHERLY FLOW FEEDS MOISTURE POOLING ALONG THE BOUNDARY SO HAVE ADDED SMALL POPS LATER THIS AFTERNOON FOR THOSE AREAS. && .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT ISSUED AT 300 AM MDT TUE MAY 12 2015 WESTERN CONUS UPPER LEVEL TROUGHING ONGOING THIS MORNING WITH A LOCAL WAA RESPONSE. WEAK LEAD IMPULSE FROM THIS SYSTEM WILL SUPPORT INCREASING MID/HIGH CLOUDS THROUGH MORNING ACROSS THE NORTHERN HALF...WITH A FEW SPRINKLES POSSIBLE ACROSS THE FAR NORTH. MEANWHILE ANOTHER UPPER LEVEL IMPULSE WILL SHIFT NE INTO THE SW CONUS AND SOUTHERN PLAINS. THIS SYSTEM WILL HELP SUPPORT DEEPER MOISTURE NORTH INTO THE AREA THROUGH TONIGHT. ONGOING PRESSURE FALLS PER THE ADVANCING WESTERN CONUS UPPER TROUGH WILL SUPPORT A LLJ TONIGHT WITH SOME FORCING FOR ASCENT PER A SLOW MOVING NW CONUS UPPER TROUGH GRAZING THE NORTHERN PLAINS TONIGHT. STEEP MID LEVEL LAPSE RATE WITH AN FGEN RESPONSE AND INCREASING ELEVATED INSTABILITY NOTED IN MU CAPES WILL SUPPORT A SLIGHT CHANCE SHOWER/TS THREAT ACROSS THE NORTHERN HALF TONIGHT. HIRES MODELS INCLUDING THE NAM SUGGEST AN ISOLD HIGH BASED SHRA/TS COULD DEVELOP OVER NE WY THIS EVENING AS CIN IS MINIMIZED PER INSOLATION...WITH ANY ACTIVITY BEING CARRIED NE BY A DEVELOPING LLJ. DID ADJUST SLIGHT CHANCE POPS SW INTO NE WY AND THE BH AFTER 00Z THIS EVENING FOR THIS...WITH A SLIGHTLY EARLIER START TIME POSSIBLE. LEE SIDE TROUGH WILL SHIFT EAST ACROSS THE FA WED MORNING AND STALL WITH THE SOUTHERN PLAINS IMPULSE SHIFTING NORTH. RENEWED FGEN FROM THIS SYSTEM WILL SUPPORT INCREASING LL CONVERGENCE ALONG AND NEAR THE SFC TROUGH WHICH WILL BE SOMEWHERE ACROSS THE EASTERN FA. INCREASING LL MOISTURE COMBINED WITH DIURNAL INSTABILITY WILL ALLOW INCREASING CHANCES FOR SHRA/TS THERE...WITH OTHER ACTIVITY POSSIBLE OVER THE BH AND NE WY PER DIURNAL HEATING IN THE PRESENCE OF UNSTABLE PROFILES/WEAK CIN. SHRA/TS CHANCES SHOULD INCREASE WED NIGHT AS THE LLJ SUSTAINED WITH ONGOING MOISTURE TRANSPORT AND INCREASING LSA FROM THE EXPECTED IMPULSE. BULK OF FORCING FROM THIS SYSTEM WILL REMAIN SE OF THE FA...INCLUDING THE ASSOCIATED PRECIP CHANCES. HAVE RETAINED HIGH CHANCE POPS...PRECLUDING LIKELY ATTM GIVEN CONVECTIVE COMPONENT TO PRECIP. AS FOR TEMPS...BUMPED HIGHS UP BOTH TODAY AND WED. SNOW PACK HAS ERODED QUITE WELL OVER MUCH OF THE AREA...WITH THE DEEPEST SNOW REMAINING OVER SW SD. STRONG SE WINDS UNDER MAY SUN SHOULD MIX WARMER AIR DOWN WITH NO PROBLEM...THUS HAVE OPTED FOR TEMPS MORE IN LINE WITH GUIDANCE. .LONG TERM...THURSDAY THROUGH MONDAY ISSUED AT 300 AM MDT TUE MAY 12 2015 THE UPPER LEVEL RIDGE WILL MOVE EAST OF THE AREA ON WEDNESDAY. THIS WILL PUT THE AREA IN ACTIVE SOUTHWEST FLOW FOR MID WEEK INTO THE WEEKEND...WITH DAILY CHANCES FOR RAIN SHOWERS AND SOME THUNDERSTORMS. A FAST-MOVING SHORTWAVE WILL SWEEP THROUGH THE CENTRAL CONUS WEDNESDAY NIGHT AND THURSDAY...AND THEN ANOTHER UPPER LOW IS PROGGED TO MOVE ACROSS THE ROCKIES AND INTO THE PLAINS THIS WEEKEND...BRINGING THE BEST CHANCES FOR ADDITIONAL RAINFALL. MODELS ARE INDICATING AROUND A HALF INCH OF QPF BY THE END OF THE WEEK...WITH AN ADDITIONAL INCH OR TWO DURING THE WEEKEND. AS FAR AS TEMPERATURES GO...MORE SPRING LIKE READINGS ARE EXPECTED FROM MID WEEK THROUGH THE WEEKEND. THEREFORE...THE PRECIPITATION SHOULD REMAIN RAIN. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 300 AM MDT TUE MAY 12 2015 GUSTY SOUTHERLY WINDS ARE EXPECTED OVER NORTHEASTERN WYOMING DURING THE REST OF THE NIGHT. THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ON TUESDAY EVENING. LCL MVFR CIGS ARE POSSIBLE WITH ANY SHOWERS OR THUNDERSTORMS...OTHERWISE VFR CIGS WILL PREVAIL. && .HYDROLOGY... ISSUED AT 300 AM MDT TUE MAY 12 2015 RUNOFF FROM RAIN AND MELTING SNOW IS CAUSING RAPID RISES IN THE LEVEL OF THE WHITE RIVER BETWEEN INTERIOR AND OACOMA. A FLOOD WARNING HAS BEEN ISSUED FOR THAT AREA AS MINOR TO MODERATE FLOODING IS FORECAST TO DEVELOP STARTING TUESDAY MORNING. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...HELGESON SHORT TERM...JC LONG TERM...7 AVIATION...7 HYDROLOGY...JC
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1258 AM CDT TUE MAY 12 2015 .DISCUSSION...UPDATED FOR 06Z AVIATION. && .AVIATION...CONVECTION IS THE MAIN AVIATION CONCERN IN THE SHORT TERM. LINE OF SHOWERS AND STORMS CONTINUES TO MOVE W TO E ACROSS SOUTH TEXAS. KEPT SHRA/TSRA REMARKS IN THE TAFS FOR THE NEXT SEVERAL HOURS. LOCALLY REDUCED VSBYS AND ERRATIC WINDS WILL OCCUR IF THUNDERSTORMS DIRECTLY IMPACT TAFS. LAST COUPLE OF HRRR RUNS INDICATE THERE COULD BE A LULL IN ACTIVITY LATER THIS MORNING AS THIS ROUND OF STORMS MOVES OFF TO THE EAST. HOWEVER...ADDITIONAL ACTIVITY WILL BE POSSIBLE AGAIN TODAY AS MOIST AIRMASS AND BOUNDARY REMAINS IN THE AREA. IFR/MVFR CEILINGS TONIGHT SHOULD TRANSITION TO MOSTLY MVFR/LOW END VFR DURING THE DAY ON TUESDAY. OUTSIDE OF THUNDERSTORMS...WINDS WILL GENERALLY BE OUT OF THE EAST AND ESE. && .PREV DISCUSSION... /ISSUED 924 PM CDT MON MAY 11 2015/ DISCUSSION...OTHER THAN THE IMPRESSIVE SUPERCELL THAT SAT OVER SOUTHERN DUVAL COUNTY FOR AWHILE BEFORE MOVING EAST-SOUTHEAST TO THE FALFURRIAS AREA...CONVECTION HAS BEEN GENERALLY DISORGANIZED. SURFACE TO 6 KM SHEAR WAS NOT QUITE AS STRONG AS ANTICIPATED AS WELL AS SLIGHTLY LOWER INSTABILITY DUE TO CLOUD COVER. BUT 00Z CRP SOUNDING STILL SHOWED MEAN LAYER CAPE AROUND 2500 J/KG AS MOISTURE HAS INCREASED SUBSTANTIALLY WITH PRECIPITABLE WATER VALUES UP TO 2.15 INCHES. SLOW MOVING SUPERCELL OVER DUVAL COUNTY LIKELY PRODUCED BETWEEN 7 AND 10 INCHES OF RAIN...BETWEEN BRUNI AND REALITOS EARLIER THIS EVENING...AS STORM INGESTED THIS HIGHER MOISTURE SOURCE ALONG THE COAST. WATER VAPOR IMAGERY SHOWS A MID LEVEL SHORT WAVE TROUGH OVER NORTHWEST MEXICO MOVING TO THE EAST. THE INCREASING MID AND UPPER LEVEL FLOW ASSOCIATED WITH THIS SHORT WAVE TROUGH WILL MOVE OUT OF NORTHEAST MEXICO INTO THE BRUSH COUNTRY OVERNIGHT. THIS WILL INCREASE THE OVERALL SHEAR PROFILE THROUGH THE NIGHT. LATEST HI- RES MODELS INDICATE THE POTENTIAL FOR A MORE ORGANIZED CONVECTIVE COMPLEX TO FORM OVER THE RIO GRANDE PLAINS AND MOVE EAST-SOUTHEAST LATER TONIGHT. INFRARED SATELLITE TRENDS SHOW COOLING CLOUD TOPS WITH AREA OF CONVECTION FROM THE WESTERN HILL COUNTRY SOUTH TO NORTHWEST OF LAREDO. HARD TO DISCERN WHERE FRONTAL BOUNDARY IS WITH AREAS OF CONVECTION BUT THE BOUNDARY MAY BE OVER THE NORTHERN COUNTIES AT THIS TIME. LOW LEVEL CONVERGENCE MAY BE SLIGHTLY HIGHER NEAR THIS BOUNDARY WITH CONVECTION TO THE NORTHWEST MOVING ALONG IT. WILL REMOVE THE MENTION OF SEVERE FOR THE REST OF TONIGHT...ALTHOUGH THREAT FOR ISOLATED SEVERE STORMS WILL STILL EXIST...AND RETAIN LOCALLY HEAVY RAINFALL IN FORECAST. NO CHANGES MADE TO THE FLASH FLOOD WATCH AREA WITH BETTER THREAT NEAR THE BOUNDARY AND OVER THE BRUSH COUNTRY AS ACTIVITY MOVES IN FROM THE WEST. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 81 74 81 74 85 / 70 60 40 50 50 VICTORIA 80 70 81 72 84 / 70 60 50 50 50 LAREDO 82 71 84 71 88 / 80 70 60 60 50 ALICE 82 72 83 72 87 / 70 60 40 60 50 ROCKPORT 80 75 80 74 83 / 70 60 40 50 50 COTULLA 78 69 83 70 88 / 90 80 70 60 50 KINGSVILLE 83 73 83 73 87 / 70 60 40 50 50 NAVY CORPUS 80 75 80 75 83 / 70 60 40 50 50 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR THE FOLLOWING ZONES: BEE...DUVAL...GOLIAD...LA SALLE...LIVE OAK... MCMULLEN...VICTORIA...WEBB. GM...NONE. && $$ TB/78...AVIATION
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
325 PM CDT TUE MAY 12 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 325 PM CDT TUE MAY 12 2015 FORECAST CONCERNS INCLUDE TEMPERATURES/FROST HEADLINES TONIGHT AND THEN PRECIP/THUNDERSTORM CHANCES THROUGH EARLY NEXT WEEK. DESPITE SOME MODEL TIMING DIFFERENCES FOR THURSDAY/S SYSTEM... 12.12Z MODEL SUITE IN GOOD OVERALL AGREEMENT THROUGH THURSDAY... BUT THEN DIVERGE ON THE CONVECTIVE DETAILS FRIDAY INTO THE WEEKEND. WILL USE A BLENDED MODEL APPROACH. FOR TONIGHT...SURFACE RIDGE AXIS WILL SLIDE ACROSS THE UPPER MS RIVER VALLEY...CENTERED ACROSS THE MN ARROWHEAD INTO NORTH-CENTRAL WI BY 12Z WEDNESDAY. SHOULD SEE SOME INCREASING SOUTHEASTERLY RETURN FLOW ACROSS SOUTHEAST MN AND NORTHEAST IA BY WEDNESDAY MORNING...BUT FOR AREAS EAST OF THE MS RIVER...A WEAK PRESSURE GRADIENT WILL LEAD TO CALM WINDS THROUGH THE NIGHT. IN ADDITION... SIMULATED IR IMAGERY FROM THE NSSL WRF SUGGESTS CURRENT CU WILL DISSIPATE AFTER SUNSET AND CIRRUS ACROSS THE DAKOTAS INTO CENTRAL MN SHOULD REMAIN JUST WEST OF THE FORECAST AREA. AS A RESULT... EXPECT MOSTLY CLEAR SKIES OVERNIGHT ALLOWING FOR MAXIMUM NOCTURNAL COOLING. WILL HOIST A FROST ADVISORY FOR ALL WI COUNTIES EXCEPT FOR BUFFALO/CRAWFORD/GRANT FROM MIDNIGHT THROUGH 7 AM WEDNESDAY WHERE OVERNIGHT TEMPERATURES WILL FALL INTO THE UPPER 20S TO MID 30S. WARM AIR ADVECTION TO INCREASE ON WEDNESDAY ALLOWING TEMPERATURES TO REBOUND BACK INTO THE UPPER 50S TO LOWER 60S. SOUTHEAST WINDS TO INCREASE BETWEEN 10 AND 20 MPH AS SURFACE PRESSURE GRADIENT STRENGTHENS ACROSS THE REGION. SHOULD SEE A FAIR AMOUNT OF SUN AS CLOUDS/PRECIP WILL BE ANCHORED TO PRIMARY WARM FRONTAL BOUNDARY FARTHER NORTH AND WEST ACROSS THE DAKOTAS INTO NORTHERN MN. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 325 PM CDT TUE MAY 12 2015 RAIN SHOWERS TO INCREASE FROM WEST TO EAST THURSDAY AND THURSDAY NIGHT AS A SHORT-WAVE EJECTS INTO THE UPPER MIDWEST FROM A BROADER PACIFIC TROUGH PARKED ALONG THE WEST COAST. FRONTOGENESIS IS RATHER WEAK WITH THIS SYSTEM...BUT MODEST WARM AIR ADVECTION/ ISENTROPIC LIFT COMBINED WITH INCREASING MOISTURE TRANSPORT WILL RESULT IN A SWATH OF SHOWERS MOVING ACROSS THE REGION. PWATS RISE ABOVE ONE INCH...RESULTING IN WIDESPREAD ACCUMULATIONS OF AT LEAST A HALF INCH AND POSSIBLY AN INCH OR HIGHER IN SOME PLACES. THUNDER WILL NOT ACCOMPANY THIS SYSTEM AS INSTABILITY IS NEARLY NON- EXISTENT. CLOUDS/RAIN WILL KEEP THURSDAY COOL WITH AFTERNOON HIGHS ONLY IN THE UPPER 50S TO LOWER 60S. CONVECTIVE POTENTIAL A BIT MURKY FRIDAY INTO SATURDAY. BEST MOISTURE TRANSPORT FOCUSES ITSELF EITHER EAST OR WEST OF THE FORECAST AREA AND WITH LITTLE UPPER LEVEL DYNAMIC SUPPORT GIVEN STRENGTHENING RIDGE...THUNDERSTORM POTENTIAL IS UNCERTAIN. BEST CHANCE WOULD BE SATURDAY WITH NORTHWARD SURGING WARM FRONT. FOR NOW...WILL FOLLOW SUPERBLEND 20 TO 30 PERCENT CHANCES. OF GREATER CERTAINTY WILL BE INCREASING TEMPERATURES WITH HIGHS IN THE 60S TO LOWER 70S ON FRIDAY RISING INTO THE MID TO UPPER 70S FOR SATURDAY. BETTER CHANCE FOR MORE ORGANIZED THUNDERSTORMS ON SUNDAY WITH APPROACHING PACIFIC TROUGH AND COLD FRONT. MUCAPE AND BULK SHEAR WITHIN THE 0 TO 6 KM LAYER INCREASE TO BETWEEN 1000 AND 1500 J/KG AND 35 TO 40 KTS RESPECTIVELY...BUT ONGOING CONVECTION EARLIER IN THE DAY COULD IMPACT AFTERNOON/EVENING THUNDERSTORM/SEVERE POTENTIAL. THIS IS HIGHLIGHTED IN THE DAY 6 SPC OUTLOOK AND SOMETHING TO WATCH THROUGH THE WEEK. DRIER/COOLER CONDITIONS RETURN MONDAY/ TUESDAY AFTER COLD FRONTAL PASSAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1201 PM CDT TUE MAY 12 2015 LOW LEVEL CYCLONIC FLOW AROUND THE SYSTEM EXITING THE NORTHERN GREAT LAKES CONTINUES TO PRODUCE CLOUDS AND FEW SHOWERS ACROSS THE AREA. FOR THE MOST PART...THE SHOWERS HAVE MOVED EAST OF BOTH TAF SITES AND DO NOT ANTICIPATE THESE BEING A PROBLEM FOR THE REMAINDER OF THE AFTERNOON. VISIBLE SATELLITE TRENDS SHOW THE WESTERN PORTION OF THE CLOUD DECK IS BECOMING MORE OPEN CELLULAR SUGGESTING THESE CLOUDS WILL DISSIPATE AT SOME POINT THIS AFTERNOON. BOTH THE 12.15Z RAP AND 12.12Z NAM SUGGEST THE LOW LEVEL MOISTURE FIELD WILL CONTINUE TO SLIDE EAST WITH THE DEPARTING SYSTEM WITH THE CLOUDS SCATTERING OUT BY MID AFTERNOON. UNTIL THIS HAPPENS...THE CEILINGS WILL FLUCTUATE BETWEEN MVFR AND VFR. THESE LOWER CLOUDS WILL TOTALLY DISSIPATE WITH SUNSET THIS EVENING AND THE WINDS WILL DIMINISH AS HIGH PRESSURE BUILDS IN. THIS HIGH WILL QUICKLY SLIP EAST OF THE AREA WEDNESDAY MORNING ALLOWING THE WINDS TO BECOME EAST AND INCREASE TO AROUND 10 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT WEDNESDAY FOR WIZ017-029-033-034-041>044-053-055. MN...NONE. IA...NONE. && $$ SHORT TERM...ROGERS LONG TERM...ROGERS AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1201 PM CDT TUE MAY 12 2015 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 334 AM CDT TUE MAY 12 2015 DEPARTING SHOWERS THIS MORNING/FROST POTENTIAL TONIGHT ARE THE MAIN CONCERNS IN THE SHORT TERM. CURRENT MAP ANALYSIS HAS DEEP 1002MB LOW JUST EAST OF LAKE SUPERIOR. MEANWHILE...WATER VAPOR IMAGERY SHOWS A CLOSED LOW OVER NORTHEAST MN WITH EMBEDDED SHORTWAVE TROUGH ENERGY ROTATING EASTWARD ACROSS SOUTHERN MN/WESTERN WI. RADAR MOSAIC/SURFACE OBS INDICATING SCATTERED SHOWER/DRIZZLE ACTIVITY MAINLY ALONG AND EAST OF THE MISSISSIPPI BEING FORCED BY THESE EMBEDDED TROUGHS. OTHERWISE... TEMPERATURES ACROSS THE AREA WERE IN THE 40S WITH SOMEWHAT BRISK WESTERLY WINDS OF 10-20 MPH. FOR TODAY...THE SURFACE/CLOSED MID-LEVEL LOW WILL SLOWLY PUSH NORTHEAST OF THE AREA THIS MORNING WITH A RIDGE OF HIGH PRESSURE BUILDING IN FROM THE WEST DURING THE AFTERNOON. KEPT SCATTERED SHOWER MENTION IN FOR AREAS ALONG/N OF THE I-90/94 CORRIDORS THROUGH THE MORNING HOURS...BUT THEN IT SHOULD BE DRY THROUGH THE AFTERNOON WITH A SLOW EROSION OF CLOUD COVER FROM SOUTHWEST TO NORTHEAST AS WELL. PLAN ON COOLER THAN NORMAL TEMPERATURES TODAY AS HIGHS ONLY MAKE IT INTO THE UPPER 40S TO THE MIDDLE 50S. THESE COOLER TEMPERATURES AND BRISK NORTHWEST WINDS WILL GIVE AN OVERALL RAW FEEL TO THE DAY. HIGH PRESSURE BUILDS INTO THE AREA TONIGHT FOR PARTLY CLOUDY SKIES AND LIGHT WINDS. THIS WILL LEAD TO SOME CHILLY OVERNIGHT LOWS AS READINGS DIP INTO THE 30S. WITH TEMPERATURES NEARING THE FREEZING MARK...FEEL THE SAND COUNTRY OF CENTRAL WI WOULD BE MOST SUSCEPTIBLE FOR FROST. HOWEVER...THERE IS SOME INDICATION OF HIGH/MID CLOUD STREAMING IN FROM UPSTREAM WARM AIR ADVECTION ACROSS THE DAKOTAS/MN. IN ADDITION...APPEARS THE RIDGE AXIS ACTUALLY PASSES INTO EASTERN WI AFTER MIDNIGHT WHICH MAY BE ENOUGH TO PRODUCE SOME LIGHT EAST WIND TO KEEP LOWER BOUNDARY LAYER MIXED ENOUGH TO PREVENT WIDESPREAD FROST. BASED ON THESE UNCERTAINTIES...HAVE HELD OFF ON FROST HEADLINES FOR NOW AND WILL LET THE DAYSHIFT ASSESS WITH MORE INPUT FROM 12Z MODEL RUNS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 334 AM CDT TUE MAY 12 2015 PLAN SOME INCREASE IN MID/HIGH CLOUD ON WEDNESDAY IN RESPONSE TO WARM FRONT PUSHING NORTH THROUGH MN. HOWEVER...DRY LOWER LAYERS THANKS TO SURFACE HIGH PRESSURE OVER THE GREAT LAKES IS EXPECTED TO KEEP THE AREA PRECIPITATION-FREE. PLAN ON HIGHS IN THE UPPER 50S TO THE MIDDLE 60S WHICH IS STILL SOME 5 DEGREES BELOW NORMAL. FOR LATER WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...WILL BE WATCHING A MID-LEVEL TROUGH MOVE FROM THE CENTRAL PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. FORCING FROM THIS WAVE AND AMPLE 850MB MOISTURE TRANSPORT ENOUGH TO DRIVE THE LIKELIHOOD OF SHOWERS. VERY LIMITED/NIL CAPE SHOULD PREVENT ANY THUNDER POTENTIAL. AS SUCH REMOVED ANY THUNDER MENTION. WITH CLOUD COVER/PRECIPITATION... TEMPERATURES WILL SUFFER A BIT ON THURSDAY AS HIGHS ONLY TOP OFF IN THE UPPER 50S TO THE LOWER 60S. SOME LINGERING SHOWERS STILL POSSIBLE MAINLY FRIDAY MORNING AS THE WAVE DEPARTS THE AREA. WITH BULK OF THIS SHOWER CHANCE IN THE MORNING...APPEARS RIDGE OF HIGH PRESSURE AND INCREASING HEIGHTS WILL RESULT IN HIGH TEMPERATURES WELL INTO THE 60S. AFTER A DRY/PLEASANT SATURDAY WITH HIGHS LOOKING TO PUSH INTO THE 70S...ACTIVE WEATHER PATTERN SETTING UP FOR THE REST OF THE WEEKEND INTO MONDAY. INCREASING SHOWERS AND THUNDERSTORM CHANCES WILL OVERSPREAD THE AREA...MAINLY CENTERED ON SUNDAY AS A POTENT LOW PRESSURE SYSTEM PUSHES TOWARD THE UPPER MISSISSIPPI RIVER VALLEY REGION. APPEARS TO BE AMPLE BULK SHEAR...WITH GFS INDICATING 0-3KM MUCAPE IN THE 500-1000J/KG RANGE SUNDAY AFTERNOON. BASED ON THIS...THE POSSIBILITY IS THERE FOR A FEW SEVERE STORMS. HOWEVER...UNCERTAINTY REMAINS GIVEN LIKELIHOOD OF ONGOING/MUDDLED CONVECTION THROUGH THE DAY ON SUNDAY. WILL BE KEEPING A CLOSE EYE ON THIS SITUATION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1201 PM CDT TUE MAY 12 2015 LOW LEVEL CYCLONIC FLOW AROUND THE SYSTEM EXITING THE NORTHERN GREAT LAKES CONTINUES TO PRODUCE CLOUDS AND FEW SHOWERS ACROSS THE AREA. FOR THE MOST PART...THE SHOWERS HAVE MOVED EAST OF BOTH TAF SITES AND DO NOT ANTICIPATE THESE BEING A PROBLEM FOR THE REMAINDER OF THE AFTERNOON. VISIBLE SATELLITE TRENDS SHOW THE WESTERN PORTION OF THE CLOUD DECK IS BECOMING MORE OPEN CELLULAR SUGGESTING THESE CLOUDS WILL DISSIPATE AT SOME POINT THIS AFTERNOON. BOTH THE 12.15Z RAP AND 12.12Z NAM SUGGEST THE LOW LEVEL MOISTURE FIELD WILL CONTINUE TO SLIDE EAST WITH THE DEPARTING SYSTEM WITH THE CLOUDS SCATTERING OUT BY MID AFTERNOON. UNTIL THIS HAPPENS...THE CEILINGS WILL FLUCTUATE BETWEEN MVFR AND VFR. THESE LOWER CLOUDS WILL TOTALLY DISSIPATE WITH SUNSET THIS EVENING AND THE WINDS WILL DIMINISH AS HIGH PRESSURE BUILDS IN. THIS HIGH WILL QUICKLY SLIP EAST OF THE AREA WEDNESDAY MORNING ALLOWING THE WINDS TO BECOME EAST AND INCREASE TO AROUND 10 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...04
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
555 AM EDT THU MAY 14 2015 .SYNOPSIS... HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH TONIGHT. THE HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY NEXT WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA NEXT TUESDAY OR WEDNESDAY. HIGH PRESSURE WILL THEN RETURN BY THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FOG HAS BECOME A BIT MORE WIDESPREAD THAN EARLIER ANTICIPATED. WEBCAMS...SURFACE OBSERVATIONS AND MEDIA REPORTS INDICATE THE FOG IS LOCALLY DENSE AT TIMES WITH VISIBILITIES 1/4 MI OR LESS. GOES FOG PRODUCTS SUGGESTS THE DENSE FOG MAY BE A BIT MORE WIDESPREAD ACROSS PARTS OF SCREVEN...JENKINS AND BULLOCH COUNTIES. A DENSE FOG ADVISORY MAY BE NEEDED FOR SOME COUNTIES IF THE DENSE FOG CONTINUES TO EXPAND IN AREA. TODAY...DEEP LAYERED HIGH PRESSURE WILL REMAIN IN TACT ACROSS THE SOUTHEAST U.S. TODAY. HIGH RESOLUTION MODELS SUGGEST A NORTHEAST WIND SURGE WORKING STEADILY DOWN THE NORTH CAROLINA COAST COULD PROVIDE ENOUGH LOW-LEVEL CONVERGENCE TO SPREAD SOME ISOLATED MARINE-BASED SHOWER ACTIVITY INLAND ACROSS PART OF UPPER CHARLESTON AND EASTERN BERKELEY COUNTIES LATER THIS MORNING. CONFIDENCE IS QUITE LOW IN THIS SCENARIO GIVEN HOW DRY THE LOWER TROPOSPHERE IS ABOVE THE BOUNDARY LAYER SO WILL CARRY SOME VERY LOW NON-ZERO POPS IN THIS AREA...BUT GENERALLY EXPECT DRY CONDITIONS TO PREVAIL. LOW-LEVEL MOISTURE RETURN WILL BEGIN TO SNEAK INTO THE FAR SOUTHERN AND SOUTHWESTERN ZONES THIS AFTERNOON AS SURFACE HIGH PRESSURE MOVES OFF THE MID-ATLANTIC COAST. FORECAST SOUNDINGS DO NOT REALLY SUPPORT MUCH IN THE WAY OF MEANINGFUL INSTABILITY IN THESE AREAS DESPITE THE SLOW EROSION OF THE CAPPING INVERSION. WITH LITTLE/NO LOW-LEVEL CONVERGENCE EXPECTED ALONG THE PURE /VERSUS RESULTANT/ SEA BREEZE CIRCULATION...POPS WILL BE KEPT BELOW MENTIONABLE THRESHOLDS FOR NOW. HIGHS WILL RANGE FROM THE LOWER 80S NORTH TO THE MID 80S CENTRAL AND SOUTH...WARMEST ACROSS FAR INTERIOR SOUTHEAST GEORGIA. MID TO UPPER 70S ARE LIKELY AT THE BEACHES WITH BREEZY ONSHORE WINDS. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... TONIGHT...LOW-LEVEL MOISTURE RETURN WILL CONTINUE THROUGH THE NIGHT AS HIGH PRESSURE SHIFTS FARTHER OFFSHORE INTO THE WESTERN ATLANTIC. MEAN MID-UPPER LEVEL RIDGING STILL LOOKS STRONG ENOUGH TO PRECLUDE SHOWER ACTIVITY OVERNIGHT...BUT A BRIEF SPRINKLE OR SHOWER CAN NOT BE COMPLETELY RULED OUT ACROSS SOUTHEAST GEORGIA OVERNIGHT...MAINLY SOUTH OF THE I-16 CORRIDOR. WILL CONTINUE TO HIGHLIGHT A DRY FORECAST FOR NOW GIVEN LOW CONFIDENCE IN ANY MEASURABLE SHOWER ACTIVITY DEVELOPING. CLOUDS WILL THICKEN THROUGH THE NIGHT WITH LOWS RANGING FROM THE LOWER 60S FAR NORTH TO THE MID 60S ELSEWHERE. SFC HIGH PRESSURE WILL BECOME CENTERED OVER THE WESTERN ATLANTIC BY THE WEEKEND...SETTING UP EAST/SOUTHEAST FLOW THAT SLOWLY DEEPENS MOISTURE OVER THE AREA AHEAD OF A SERIES OF SUBTLE H5 SHORTWAVES THAT ROUND THE NORTHWEST FRINGE OF A MID LVL RIDGE CENTERED TO OUR SOUTH. A SLIGHT CHANCE OF DIURNAL SHOWERS AND/OR THUNDERSTORMS WILL BE POSSIBLE OVER INLAND PORTIONS OF SOUTHEAST GEORGIA ON FRIDAY AND SATURDAY...FOLLOWED BY CHANCES OF AFTERNOON SHOWERS AND THUNDERSTORMS ON SUNDAY...MAINLY AWAY FROM THE COAST WHERE LOW LVL MOISTURE IS HIGHEST AND A SEABREEZE PROGRESSES INLAND. TEMPS SHOULD BE A FEW DEGREES COOLER ON FRIDAY...IN THE UPPER 70S TO LOWER 80S...BUT A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE WEEKEND. IN GENERAL...HIGH TEMPS SHOULD RANGE IN THE LOW TO MID 80S ON SATURDAY...THEN MID TO UPPER 80S ON SUNDAY...WARMEST AWAY FROM THE COAST. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO RETURN TO THE AREA WHILE WEAK H5 SHORTWAVES CONTINUE TO ROUND NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF SHOWERS AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING INTO EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A COLD FRONT WILL THEN APPROACH FROM THE NORTH/NORTHWEST ON TUESDAY BEFORE PUSHING THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. HIGHER COVERAGE OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITH COLD FROPA. HIGH PRESSURE SHOULD THEN BUILD INTO THE AREA FROM THE NORTH/NORTHWEST INTO THURSDAY. TEMPS WILL BE ON A WARMING TREND NEXT WEEK...WITH MAX TEMPS REACHING THE UPPER 80S TO LOWER 90S ON TUESDAY AHEAD OF THE APPROACHING COLD FRONT. TEMPS SHOULD BE A FEW DEGREES COOLER ON WEDNESDAY AS HIGH PRESSURE BUILDS BEHIND THE FRONT THROUGH THURSDAY. OVERNIGHT LOWS SHOULD RANGE IN THE MID TO UPPER 60S AWAY FROM THE COAST. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY NEXT WEEK. && .MARINE... TODAY...A NORTHEAST WIND SURGE WILL OVERSPREAD THE WATERS TODAY WITH DIRECTIONS SLOWLY VEERING TO THE EAST. WINDS LOOK TO GO NO HIGHER THAN 15-20 KT FOR ALL LEGS WITH GUSTS HOLDING BELOW 25 KT. SEAS WILL BUILD IN THE NORTHEAST FETCH...REACHING 3-5 FT NEARSHORE WATERS AND A SOLID 5 FT FOR THE GEORGIA OFFSHORE WATERS BY LATE THIS AFTERNOON. ATTM BOTH WINDS AND SEAS LOOK TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. TONIGHT...MODEST ONSHORE WINDS WILL PERSIST...ALTHOUGH SPEEDS WILL DIMINISH SOMEWHAT. WINDS ARE EXPECTED TO DROP TO 10-15 KT NEARSHORE WATERS...BUT REMAIN 15-20 KT FOR THE GEORGIA OFFSHORE WATERS. SEAS WILL BUILD A BIT MORE...PEAKING 3-5 FT NEARSHORE WATERS WITH 4-6 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE ISSUED FOR THE GEORGIA OFFSHORE LEG...BEGINNING AT 6 PM THIS EVENING AND REMAINING IN FORCE THROUGH THE NIGHT. FRIDAY THROUGH MONDAY...MARGINAL SMALL CRAFT ADVISORY CONDITIONS SHOULD LINGER IN OFFSHORE GEORGIA WATERS INTO EARLY FRIDAY...BEFORE HIGH PRESSURE BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. WINDS WILL THEN IMPROVE THROUGH THE WEEKEND AS THE PRESSURE GRADIENT WEAKENS OVER THE COASTAL WATERS. SEAS WILL ALSO SUBSIDE THROUGH THE WEEKEND...RANGING NO HIGHER THAN 2-4 FT. HIGHEST SEAS ARE EXPECTED IN OFFSHORE GEORGIA WATERS. && .TIDES/COASTAL FLOODING... ONSHORE WINDS COMBINED WITH LUNAR INFLUENCES WILL HELP PUSH TIDE LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL TIDES THROUGH LATE WEEK...POSSIBLY CAUSING SHALLOW COASTAL FLOODING LATER IN THE WEEK DURING THE EVENING HIGH TIDES...MAINLY ALONG THE SOUTH CAROLINA COAST SATURDAY AND SUNDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 11 AM EDT FRIDAY FOR AMZ374. && $$ ST/DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
409 AM EDT THU MAY 14 2015 .SYNOPSIS... HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH TONIGHT. THE HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY NEXT WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA NEXT TUESDAY OR WEDNESDAY. HIGH PRESSURE WILL THEN RETURN BY THURSDAY. && .NEAR TERM /THROUGH TODAY/... THROUGH SUNRISE...SOME VERY SHALLOW GROUND FOG HAS DEVELOPED ALONG PORTIONS OF THE GEORGIA COAST THIS MORNING. WEBCAMS AND SURFACE OBSERVATIONS INDICATE THE FOG IS QUITE SHALLOW IN NATURE AND SHOULD NOT SIGNIFICANTLY IMPACT TRAVEL THIS MORNING. THE FOG COULD EXPAND NORTH ALONG THE LOWER SOUTH CAROLINA THROUGH SUNRISE. TODAY...DEEP LAYERED HIGH PRESSURE WILL REMAIN IN TACT ACROSS THE SOUTHEAST U.S. TODAY. HIGH RESOLUTION MODELS SUGGEST A NORTHEAST WIND SURGE WORKING STEADILY DOWN THE NORTH CAROLINA COAST COULD PROVIDE ENOUGH LOW-LEVEL CONVERGENCE TO SPREAD SOME ISOLATED MARINE-BASED SHOWER ACTIVITY INLAND ACROSS PART OF UPPER CHARLESTON AND EASTERN BERKELEY COUNTIES LATER THIS MORNING. CONFIDENCE IS QUITE LOW IN THIS SCENARIO GIVEN HOW DRY THE LOWER TROPOSPHERE IS ABOVE THE BOUNDARY LAYER SO WILL CARRY SOME VERY LOW NON-ZERO POPS IN THIS AREA...BUT GENERALLY EXPECT DRY CONDITIONS TO PREVAIL. LOW-LEVEL MOISTURE RETURN WILL BEGIN TO SNEAK INTO THE FAR SOUTHERN AND SOUTHWESTERN ZONES THIS AFTERNOON AS SURFACE HIGH PRESSURE MOVES OFF THE MID-ATLANTIC COAST. FORECAST SOUNDINGS DO NOT REALLY SUPPORT MUCH IN THE WAY OF MEANINGFUL INSTABILITY IN THESE AREAS DESPITE THE SLOW EROSION OF THE CAPPING INVERSION. WITH LITTLE/NO LOW-LEVEL CONVERGENCE EXPECTED ALONG THE PURE /VERSUS RESULTANT/ SEA BREEZE CIRCULATION...POPS WILL BE KEPT BELOW MENTIONABLE THRESHOLDS FOR NOW. HIGHS WILL RANGE FROM THE LOWER 80S NORTH TO THE MID 80S CENTRAL AND SOUTH...WARMEST ACROSS FAR INTERIOR SOUTHEAST GEORGIA. MID TO UPPER 70S ARE LIKELY AT THE BEACHES WITH BREEZY ONSHORE WINDS. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... TONIGHT...LOW-LEVEL MOISTURE RETURN WILL CONTINUE THROUGH THE NIGHT AS HIGH PRESSURE SHIFTS FARTHER OFFSHORE INTO THE WESTERN ATLANTIC. MEAN MID-UPPER LEVEL RIDGING STILL LOOKS STRONG ENOUGH TO PRECLUDE SHOWER ACTIVITY OVERNIGHT...BUT A BRIEF SPRINKLE OR SHOWER CAN NOT BE COMPLETELY RULED OUT ACROSS SOUTHEAST GEORGIA OVERNIGHT...MAINLY SOUTH OF THE I-16 CORRIDOR. WILL CONTINUE TO HIGHLIGHT A DRY FORECAST FOR NOW GIVEN LOW CONFIDENCE IN ANY MEASURABLE SHOWER ACTIVITY DEVELOPING. CLOUDS WILL THICKEN THROUGH THE NIGHT WITH LOWS RANGING FROM THE LOWER 60S FAR NORTH TO THE MID 60S ELSEWHERE. SFC HIGH PRESSURE WILL BECOME CENTERED OVER THE WESTERN ATLANTIC BY THE WEEKEND...SETTING UP EAST/SOUTHEAST FLOW THAT SLOWLY DEEPENS MOISTURE OVER THE AREA AHEAD OF A SERIES OF SUBTLE H5 SHORTWAVES THAT ROUND THE NORTHWEST FRINGE OF A MID LVL RIDGE CENTERED TO OUR SOUTH. A SLIGHT CHANCE OF DIURNAL SHOWERS AND/OR THUNDERSTORMS WILL BE POSSIBLE OVER INLAND PORTIONS OF SOUTHEAST GEORGIA ON FRIDAY AND SATURDAY...FOLLOWED BY CHANCES OF AFTERNOON SHOWERS AND THUNDERSTORMS ON SUNDAY...MAINLY AWAY FROM THE COAST WHERE LOW LVL MOISTURE IS HIGHEST AND A SEABREEZE PROGRESSES INLAND. TEMPS SHOULD BE A FEW DEGREES COOLER ON FRIDAY...IN THE UPPER 70S TO LOWER 80S...BUT A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE WEEKEND. IN GENERAL...HIGH TEMPS SHOULD RANGE IN THE LOW TO MID 80S ON SATURDAY...THEN MID TO UPPER 80S ON SUNDAY...WARMEST AWAY FROM THE COAST. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO RETURN TO THE AREA WHILE WEAK H5 SHORTWAVES CONTINUE TO ROUND NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF SHOWERS AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING INTO EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A COLD FRONT WILL THEN APPROACH FROM THE NORTH/NORTHWEST ON TUESDAY BEFORE PUSHING THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. HIGHER COVERAGE OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITH COLD FROPA. HIGH PRESSURE SHOULD THEN BUILD INTO THE AREA FROM THE NORTH/NORTHWEST INTO THURSDAY. TEMPS WILL BE ON A WARMING TREND NEXT WEEK...WITH MAX TEMPS REACHING THE UPPER 80S TO LOWER 90S ON TUESDAY AHEAD OF THE APPROACHING COLD FRONT. TEMPS SHOULD BE A FEW DEGREES COOLER ON WEDNESDAY AS HIGH PRESSURE BUILDS BEHIND THE FRONT THROUGH THURSDAY. OVERNIGHT LOWS SHOULD RANGE IN THE MID TO UPPER 60S AWAY FROM THE COAST. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY NEXT WEEK. && .MARINE... TODAY...A NORTHEAST WIND SURGE WILL OVERSPREAD THE WATERS TODAY WITH DIRECTIONS SLOWLY VEERING TO THE EAST. WINDS LOOK TO GO NO HIGHER THAN 15-20 KT FOR ALL LEGS WITH GUSTS HOLDING BELOW 25 KT. SEAS WILL BUILD IN THE NORTHEAST FETCH...REACHING 3-5 FT NEARSHORE WATERS AND A SOLID 5 FT FOR THE GEORGIA OFFSHORE WATERS BY LATE THIS AFTERNOON. ATTM BOTH WINDS AND SEAS LOOK TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. TONIGHT...MODEST ONSHORE WINDS WILL PERSIST...ALTHOUGH SPEEDS WILL DIMINISH SOMEWHAT. WINDS ARE EXPECTED TO DROP TO 10-15 KT NEARSHORE WATERS...BUT REMAIN 15-20 KT FOR THE GEORGIA OFFSHORE WATERS. SEAS WILL BUILD A BIT MORE...PEAKING 3-5 FT NEARSHORE WATERS WITH 4-6 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE ISSUED FOR THE GEORGIA OFFSHORE LEG...BEGINNING AT 6 PM THIS EVENING AND REMAINING IN FORCE THROUGH THE NIGHT. FRIDAY THROUGH MONDAY...MARGINAL SMALL CRAFT ADVISORY CONDITIONS SHOULD LINGER IN OFFSHORE GEORGIA WATERS INTO EARLY FRIDAY...BEFORE HIGH PRESSURE BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. WINDS WILL THEN IMPROVE THROUGH THE WEEKEND AS THE PRESSURE GRADIENT WEAKENS OVER THE COASTAL WATERS. SEAS WILL ALSO SUBSIDE THROUGH THE WEEKEND...RANGING NO HIGHER THAN 2-4 FT. HIGHEST SEAS ARE EXPECTED IN OFFSHORE GEORGIA WATERS. && .TIDES/COASTAL FLOODING... ONSHORE WINDS COMBINED WITH LUNAR INFLUENCES WILL HELP PUSH TIDE LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL TIDES THROUGH LATE WEEK...POSSIBLY CAUSING SHALLOW COASTAL FLOODING LATER IN THE WEEK DURING THE EVENING HIGH TIDES...MAINLY ALONG THE SOUTH CAROLINA COAST SATURDAY AND SUNDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 11 AM EDT FRIDAY FOR AMZ374. && $$ ST/DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
130 AM EDT THU MAY 14 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD FROM THE NORTH OVERNIGHT INTO LATE WEEK. THE HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY NEXT WEEK. A WEAK COLD FRONT COULD PUSH THROUGH THE AREA NEXT TUESDAY OR WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... MINOR ADJUSTMENTS FOR CURRENT TRENDS. NOT TOO KEAN ON FOG OR STRATUS DEVELOPMENT GIVEN LATEST HIGH RESOLUTION DATA. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/... MODELS IN GOOD AGREEMENT THAT HIGH PRESSURE RIDGING WILL PREVAIL THIS PERIOD ALONG WITH LIMITED MOISTURE KEEPING RAIN CHANCES BELOW NORMAL. HOWEVER...THAT DOES NOT MEAN IT WILL BE DRY EVERYWHERE THE ENTIRE TIME...ESPECIALLY CLOSER TO THE ALTAMAHA RIVER WHERE THE BEST MOISTURE AND INSTABILITY ARE EXPECTED. TEMPERATURES SHOULD BE NEAR TO SLIGHTLY BELOW NORMAL...WITH THE WARMEST TEMPS ON SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO RETURN TO THE AREA WHILE NUMEROUS H5 SHORTWAVES ROUND THE NORTH/NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF SHOWERS AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING INTO EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A WEAK COLD FRONT COULD THEN APPROACH THE AREA FROM THE NORTH/NORTHWEST TUESDAY AND/OR WEDNESDAY...LEADING TO HIGHER COVERAGE OF SHOWERS AND THUNDERSTORMS OVER THE AREA. TEMPS WILL BE ON A WARMING TREND NEXT WEEK...WITH MAX TEMPS REACHING THE UPPER 80S TO AROUND 90 AWAY FROM THE COAST. TEMPS COULD BE A FEW DEGREES COOLER ON WEDNESDAY SHOULD COLD FROPA OCCUR. OVERNIGHT LOWS SHOULD RANGE IN THE MID TO UPPER 60S AWAY FROM THE COAST. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY NEXT WEEK. && .MARINE... OVERNIGHT...A WEAK PRESSURE GRADIENT AND ONSHORE WINDS LESS THAN 15 KT WILL GIVE WAY TO HIGH PRESSURE BUILDING FROM THE NORTH...TIGHTENING THE GRADIENT AND SUPPORTING A MODEST SURGE OF NE WINDS AS HIGH AS 15-20 KT ACROSS SC WATERS LATE. EARLY SEAS OF 1-3 FT WILL BUILD TO 2-4 FT LATE...HIGHEST BEYOND 20 NM. THURSDAY THROUGH SUNDAY...HIGH PRESSURE TO THE NORTH WILL SLOWLY SHIFT OFFSHORE INTO THE ATLANTIC AND PERSIST THERE THROUGH THE WEEKEND. THIS PATTERN WILL RESULT IN WINDS/SEAS THAT MOSTLY REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. HOWEVER...WHILE THE HIGH IS CLOSE TO THE AREA THURSDAY...A TIGHT PRESSURE GRADIENT WILL EXIST OVER THE AREA AND WE CANNOT RULE OUT SOME 25 KT GUSTS OVER THE NEAR SHORE WATERS AND 6 FT SEAS BEYOND 20 NM INTO THURSDAY NIGHT. && .TIDES/COASTAL FLOODING... ONSHORE WINDS WILL HELP PUSH TIDE LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL TIDES THROUGH LATE WEEK...POSSIBLY CAUSING SHALLOW COASTAL/SALT WATER FLOODING LATER IN THE WEEK DURING THE EVENING HIGH TIDES...MAINLY ALONG THE SC COAST. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
423 AM EDT THU MAY 14 2015 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EDT THU MAY 14 2015 WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL... STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE MID 40S TO THE MID 50S. THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO VALLEY AHEAD OF IT. EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL CONTINUE WITH A DRY FORECAST TODAY. TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS GUIDANCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 329 AM EDT THU MAY 14 2015 FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE PERIOD. UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED. SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40 POPS OVER THE ENTIRE FORECAST AREA. REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT. TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK. WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY FORECAST AFTER MONDAY. && .AVIATION /DISCUSSION FOR THE 140900Z KIND TAF UPDATE/... ISSUED AT 423 AM EDT THU MAY 14 2015 WILL VEER THE WIND FORECAST AND INCREASE THE SPEEDS SOME ON THE UPDATE BASED ON CURRENT OBSERVATIONS. PREVIOUS DISCUSSION FOLLOWS. VFR THROUGH THE PERIOD. EXPECT ONLY GRADUALLY INCREASING MID AND HIGH CLOUD THROUGH THE PERIOD AS HIGH PRESSURE ALOFT AND AT THE SURFACE SLIDE EASTWARD. WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD. NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...NIELD/JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
329 AM EDT THU MAY 14 2015 .UPDATE... THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EDT THU MAY 14 2015 WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL... STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE MID 40S TO THE MID 50S. THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO VALLEY AHEAD OF IT. EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL CONTINUE WITH A DRY FORECAST TODAY. TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS GUIDANCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 329 AM EDT THU MAY 14 2015 FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE PERIOD. UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED. SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40 POPS OVER THE ENTIRE FORECAST AREA. REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT. TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK. WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY FORECAST AFTER MONDAY. && .AVIATION /DISCUSSION FOR THE 14/06Z TAFS/... ISSUED AT 1230 AM EDT THU MAY 14 2015 VFR THROUGH THE PERIOD. EXPECT ONLY GRADUALLY INCREASING MID AND HIGH CLOUD THROUGH THE PERIOD AS HIGH PRESSURE ALOFT AND AT THE SURFACE SLIDE EASTWARD. WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD. NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...NIELD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
332 AM CDT THU MAY 14 2015 .SYNOPSIS... ISSUED AT 312 AM CDT THU MAY 14 2015 AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN 2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION SHOULD CONTINUE TO BE SEEN. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CDT THU MAY 14 2015 TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z. HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10 PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY. TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT. MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700 PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH. ERVIN .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 312 AM CDT THU MAY 14 2015 FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S. THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500 J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD. CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST. THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN. HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK 850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI. SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER THAN FRIDAY AS WELL. SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE ISOLATED. FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION VECTORS AND PWAT VALUES NEAR 1.50 INCHES. SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE SFC COLD FRONT. MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1149 PM CDT WED MAY 13 2015 VFR CONDITIONS WILL CONTINUE 15Z/14 AS CIGS SLOWLY LOWER DUE TO AN APPROACHING STORM SYSTEM FROM THE PLAINS. AFT 15Z/14 CONDITIONS WILL SLOWLY DETERIORATE TO MVFR THROUGH 00Z/15. AFT 00Z/15 THERE IS A SMALL POSSIBILITY OF IFR CIGS DEVELOPING. HOWEVER...THIS POSSIBILITY WAS NOT INCLUDED IN THE 06Z TAFS DUE TO UNCERTAINTY ON HOW LOW CLOUD HEIGHTS WILL GET. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...ERVIN SHORT TERM...ERVIN LONG TERM...UTTECH AVIATION...08
AREA FORECAST DISCUSSION
NWS HASTINGS NE
420 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT THU MAY 14 2015 ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3) TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK). STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM) WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID 0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS. LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN MOST PLACES. NOW LOOKING AHEAD FORECAST-WISE... EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO- NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST. HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE POP IS BELOW 20 PERCENT. WOULD NORMALLY A BIT MORE CONCERNED ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING. TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY. THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13 NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST BREEZES THIS MORNING WILL STEADILY MORE SOUTHWESTERLY IF NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT EXPECTED TO AVERAGE MORE THAN 10-15 MPH. THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN 1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE- MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST. COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500 J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61 DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY 1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE FOCUS REMAIN ON THE THUNDERSTORM CHANCES. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 420 AM CDT THU MAY 14 2015 A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS. OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK. STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR 60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO. AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY... EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER. CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID WEEK TO BE MORE ISOLATED ACROSS THE REGION. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 100 AM CDT THU MAY 14 2015 OVERALL NO MAJOR CHANGES FROM PREVIOUS 00Z PACKAGE...AS A COMBINATION OF MVFR/IFR CONDITIONS ARE EXPECTED TO DOMINATE AT LEAST THE FIRST HALF OF THE PERIOD...AND POSSIBLY A FEW HOURS BEYOND...WITH VFR CEILING/VISIBILITY THEN RETURNING FROM ROUGHLY MID-AFTERNOON ONWARD. WHILE THIS GENERAL TREND CARRIES FAIRLY HIGH CONFIDENCE...THERE ARE PLENTY OF QUESTION MARKS ESPECIALLY WITH REGARD TO VISIBILITY...AND WHETHER OR NOT AT LEAST A BRIEF PERIOD OF MORE SUBSTANTIAL FOG COULD SET IN BEHIND THE RAIN SHIELD THIS MORNING...BUT FOR NOW HAVE NOT GONE TOO PESSIMISTIC DOWN THIS ROAD. SPEAKING OF RAIN...AT LEAST THROUGH THESE FIRST 5-6 HOURS OR SO...A FAIRLY STEADY LIGHT RAIN WILL PERSIST AT BOTH TERMINALS BEFORE POSSIBLY TRANSITIONING TO A FEW HOURS OF LIGHT DRIZZLE BEFORE PRECIP ENDS COMPLETELY. WILL AIM FOR A RETURN TO PREVAILING VFR VISIBILITY BY MID-LATE MORNING...BUT WILL HOLD ONTO AN MVFR CEILING INTO MID-AFTERNOON BEFORE SCATTERING OUT/LIFTING TO VFR LEVELS. CONFIDENCE IS FAIRLY HIGH IN VFR CONDITIONS FOR THE LATTER SEVERAL HOURS OF THE PERIOD THURSDAY EVENING. THERE IS AN OUTSIDE CHANCE THAT ISOLATED SHOWERS/THUNDERSTORMS COULD BE STARTING TO DEVELOP IN THE GENERAL AREA TOWARD THE VERY END OF THE PERIOD...BUT THIS SEEMS MORE LIKELY DURING THE FOLLOWING 6 HOURS SO WILL HOLD OFF ON ANY MENTION FOR NOW. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...ROSSI AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
359 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT THU MAY 14 2015 ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3) TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK). STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM) WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID 0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS. LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN MOST PLACES. NOW LOOKING AHEAD FORECAST-WISE... EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO- NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST. HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE POP IS BELOW 20 PERCENT. WOULD NORMALLY A BIT MORE CONCERNED ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING. TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY. THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13 NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST BREEZES THIS MORNING WILL STEADILY MORE SOUTHWESTERLY IF NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT EXPECTED TO AVERAGE MORE THAN 10-15 MPH. THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN 1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE- MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST. COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500 J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61 DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY 1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE FOCUS REMAIN ON THE THUNDERSTORM CHANCES. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 400 AM CDT THU MAY 14 2015 THIS SECTION WILL BE ADDED WITHIN THE NEXT HOUR...STAY TUNED. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 100 AM CDT THU MAY 14 2015 OVERALL NO MAJOR CHANGES FROM PREVIOUS 00Z PACKAGE...AS A COMBINATION OF MVFR/IFR CONDITIONS ARE EXPECTED TO DOMINATE AT LEAST THE FIRST HALF OF THE PERIOD...AND POSSIBLY A FEW HOURS BEYOND...WITH VFR CEILING/VISIBILITY THEN RETURNING FROM ROUGHLY MID-AFTERNOON ONWARD. WHILE THIS GENERAL TREND CARRIES FAIRLY HIGH CONFIDENCE...THERE ARE PLENTY OF QUESTION MARKS ESPECIALLY WITH REGARD TO VISIBILITY...AND WHETHER OR NOT AT LEAST A BRIEF PERIOD OF MORE SUBSTANTIAL FOG COULD SET IN BEHIND THE RAIN SHIELD THIS MORNING...BUT FOR NOW HAVE NOT GONE TOO PESSIMISTIC DOWN THIS ROAD. SPEAKING OF RAIN...AT LEAST THROUGH THESE FIRST 5-6 HOURS OR SO...A FAIRLY STEADY LIGHT RAIN WILL PERSIST AT BOTH TERMINALS BEFORE POSSIBLY TRANSITIONING TO A FEW HOURS OF LIGHT DRIZZLE BEFORE PRECIP ENDS COMPLETELY. WILL AIM FOR A RETURN TO PREVAILING VFR VISIBILITY BY MID-LATE MORNING...BUT WILL HOLD ONTO AN MVFR CEILING INTO MID-AFTERNOON BEFORE SCATTERING OUT/LIFTING TO VFR LEVELS. CONFIDENCE IS FAIRLY HIGH IN VFR CONDITIONS FOR THE LATTER SEVERAL HOURS OF THE PERIOD THURSDAY EVENING. THERE IS AN OUTSIDE CHANCE THAT ISOLATED SHOWERS/THUNDERSTORMS COULD BE STARTING TO DEVELOP IN THE GENERAL AREA TOWARD THE VERY END OF THE PERIOD...BUT THIS SEEMS MORE LIKELY DURING THE FOLLOWING 6 HOURS SO WILL HOLD OFF ON ANY MENTION FOR NOW. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...ROSSI AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 326 AM CDT THU MAY 14 2015 TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR HIGHS IN THE 70S TO 80 SOUTH. WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING SCATTERED TSTMS FROM 06Z ONWARD. INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 326 AM CDT THU MAY 14 2015 LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE. DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS. LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION. THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE. MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK NORTH AND EAST THROUGH THE EVENING. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7 RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR WIDESPREAD QPF AND STRONG MODEL CONSENSUS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1125 PM CDT WED MAY 13 2015 FOR THE KLBF TERMINAL...LOOK FOR RAIN SHOWERS TO COME TO AN END BY 07Z THURSDAY. PATCHY FOG WILL FOLLOW THE RAIN SHOWERS WITH CIGS FALLING AS LOW AS 400 FT AGL WITH VISBYS DOWN TO 2SM. CIGS WILL IMPROVE BY MID MORNING THURSDAY WITH MVFR CIGS OF 1500 FT AGL. SKIES WILL CLEAR THURSDAY AFTERNOON AND REMAIN CLEAR THROUGH 06Z FRIDAY. FOR THE KVTN TERMINAL...EXPECT LIGHT RAIN SHOWERS TO CONTINUE THROUGH 10Z THURSDAY WITH PATCHY FOG POSSIBLE THEREAFTER THROUGH MID MORNING THURSDAY. CIGS MAY FALL AS LOW AS 700 FT OVERNIGHT WITH VISBYS DOWN TO 4SM. MVFR CIGS AROUND 1500 FT AGL WILL DEVELOP AFTER MID MORNING...WITH VFR CIGS OF 5000 FT AGL EXPECTED THURSDAY AFTERNOON. SKIES WILL CLEAR THURSDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MARTIN AVIATION...CLB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1149 PM CDT WED MAY 13 2015 .SHORT TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 305 PM CDT WED MAY 13 2015 TONIGHT LATEST SHORT TERM PROGS IN AGREEMENT SHOWING THAT GOING RAINFALL FCST FOR TONIGHT IS ON TRACK WITH PCPN ACTIVITY DEVELOPING OVER KS THEN EXPANDING NWD INTO THE CWA EARLY THIS EVENING. GIVEN COMBINATION OF UPPER SUPPORT VIA POTENT VORT MAX/STRONG DIVG WORKING IN TANDEM WITH RATHER MOIST 305K UPGLIDE...SEEMS REASONABLE TO ASSUME THAT SEVERAL LOCATIONS SHOULD SEE RAINFALL TOTALS OF AT LEAST HALF AN INCH MAINLY OVER THE SRN CWA WHERE LIFT/MOISTURE WILL BE MORE PREVALENT. IN ADDITION...MODELS ARE SHOWING INSTABILITY PARAMETERS WILL BE WEAK AT BEST SO ANY TSTM DEVELOPMENT SHOULD BE ISOLATED. DEE THURSDAY THROUGH SATURDAY TIMING AND POTENTIAL FOR SEVERE STORMS BOTH FRIDAY AND SATURDAY WILL BE THE MAIN FORECAST CONCERNS. OUR AREA WILL GENERALLY BE IN SOUTH OR SOUTHWEST MID TROPOSPHERIC FLOW THE NEXT FEW DAYS. WATER VAPOR IMAGERY EARLY THIS WEDNESDAY AFTERNOON...IN COMBINATION WITH EARLY AFTERNOON RAP MODEL INTITIALIZATIONS...SHOWED FAIRLY IMPRESSIVE SHORTWAVE TROUGH FROM COLORADO DOWN INTO WEST TEXAS. THIS WILL LIFT NORTHEAST ACROSS THE AREA TONIGHT AND THURSDAY. BRIEF SHORTWAVE RIDGING BUILDS IN FOR LATE THURSDAY/EARLY THURSDAY NIGHT...WHILE A STRONG CLOSED LOW DIGS DOWN INTO NEVADA AND CALIFORNIA. GENERAL MODEL CONSENSUS SHOWS THE CENTER OF THAT 500 MB LOW SHOULD LIFT OUT INTO NORTHEAST WYOMING OR SOUTHEAST MONTANA BY SATURDAY EVENING. THURSDAY...SHOWERS WILL LINGER AT LEAST IN THE MORNING...WITH ISOLATED THUNDER POSSIBLE. CHANCES DECREASE THROUGH THE AFTERNOON. EXPECT AT LEAST THE SOUTHWEST HALF OF OUR FORECAST AREA TO SEE SOME AFTERNOON SUNSHINE AND THAT SHOULD HELP PUSH HIGHS INTO THE 70S THERE. AREAS FROM AROUND YANKTON DOWN TO ONAWA...HARLAN AND RED OAK MAY ONLY TOP OUT FROM 65 TO 70. PCPN AMOUNTS THURSDAY ARE EXPECTED TO BE MOSTLY UNDER 0.25 INCHES. A WEAK COLD FRONT WILL SETTLE DOWN INTO THE FORECAST AREA THURSDAY NIGHT AND THEN STALL. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND NORTH OF THE BOUNDARY THURSDAY NIGHT AS THE LOW LEVEL JET INCREASES AND CAUSES ISENTROPIC LIFT. BEST FOCUS SEEMS TO BE OVER SOUTHEAST NEBRASKA. FRIDAY AND FRIDAY NIGHT WILL BE INTERESTING. SOUTHERLY LOW LEVEL FLOW INCREASES AS LOW PRESSURE INITIALLY OVER NORTHEAST COLORADO AT 12Z FRIDAY LIFTS NORTH TO WEST/NORTHWEST OF VALENTINE BY 06Z SATURDAY. HIGHS FRIDAY SHOULD REACH 75 TO 80...PUSHING BOUNDARY LAYER CAPE VALUES INTO THE 1500 TO 3000 J/KG RANGE. 0-6 KM AGL BULK SHEAR VALUES SHOULD BE MOSTLY 25-40 KNOTS. STORMS MAY INITIALLY BE MOSTLY NORTH OF THE FRONT...BUT THEN COULD ALSO DEVELOP IN THE WARM SECTOR OR FARTHER BACK TO THE WEST IN CENTRAL NEBRASKA LATER IN THE DAY. DETAILS SHOULD BECOME MORE CLEAR WITH THURSDAY MODEL RUNS ON THE LOCATION OF FRONTAL BOUNDARIES WHICH WILL HELP FOCUS THE ACTIVITY IN THE AFTERNOON AND EVENING. STORM COVERAGE MAY DROP OFF DRASTICALLY AFTER MIDNIGHT. SATURDAY...OVERALL PARAMETERS ARE EXPECTED TO BE IN PLACE FOR ANOTHER POSSIBLE SEVERE EVENT...BUT NOT COMPLETELY SOLD ON THAT SINCE IT WILL AT LEAST SOMEWHAT DEPEND ON WHAT HAPPENS FRIDAY. MID LEVEL WINDS SHOULD INCREASE AND THEREFORE BULK SHEAR VALUES MAY END UP HIGHER THAN THOSE FRIDAY. TIMING OF CONVECTION WILL BE THE KEY. MILLER .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 305 PM CDT WED MAY 13 2015 STORMS SHOULD LINGER INTO SATURDAY NIGHT...WITH SHOWERS/A FEW EMBEDDED STORMS POSSIBLE SUNDAY MORNING. THE 12Z GFS WAS MOSTLY DRY IN OUR AREA SUNDAY...BUT THE 12Z ECMWF WAS ABOUT 6 HOURS SLOWER LIFTING PCPN OUT OF THE AREA. SO...FOR NOW WE HAVE KEPT SOME LOW POPS SUNDAY IN OUR NORTHERN ZONES SUNDAY. SUNDAY NIGHT THROUGH TUESDAY SHOULD BE LESS ACTIVE AS HIGH PRESSURE BUILDS INTO THE REGION WITH COOL TEMPERATURES. SOME LOWS COULD DROP DOWN TO NEAR 40. IT APPEARS THAT CHANCES FOR SHOWERS/STORMS WILL INCREASE AGAIN BY TUESDAY NIGHT AND WEDNESDAY AS SHORTWAVE ENERGY MOVES IN FROM THE WEST/SOUTHWEST. MILLER && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1140 PM CDT WED MAY 13 2015 VSBYS/CIGS HAVE DROPPED TO MVFR WITH THE BAND OF RAIN THAT MOVED ACROSS THE FORECAST AREAS THIS EVENING. THESE CONDITIONS WILL CONTINUE THROUGH THURSDAY MORNING...HOWEVER...OBS/RAP13 SHOW THERE IS AN AREA OF DRIER AIR THAT WILL AFFECT THE KOMA/KLNK WITH MORE VARIABLE CONDITIONS...WHERE VFR CONDITIONS WILL BE POSSIBLE BEFORE DROPPING BACK TO MVFR/IFR THROUGH 18-00Z. LOOK FOR IMPROVING CONDITIONS WITH DECREASING CLOUDS FROM WEST TO EAST THURSDAY AFTERNON. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DEE/MILLER LONG TERM...MILLER AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
256 AM PDT THU MAY 14 2015 .SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES. && .SHORT TERM...THROUGH SATURDAY NIGHT. THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS THE MOJAVE DESERT. WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON. WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE... BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH. WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST ANY WIND HEADLINES. BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH. FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL AVERAGES. ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY BUT STILL BE AROUND 15 DEGREES BELOW NORMAL. .LONG TERM...SUNDAY THROUGH THURSDAY. SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON. THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND. && .AVIATION... FOR MCCARRAN...INCREASING CLOUDS AND LOWERING CEILINGS EXPECTED TODAY AS A PACIFIC STORM IMPACTS THE REGION. SOUTH WINDS OF 15-25KT EXPECTED WITH GUSTS TO 30KTS BUT SOME VARIABILITY POSSIBLE WHILE SHOWERS MOVE THROUGH THE VALLEY IN THE LATE AFTERNOON. CIGS FALLING IN THE 8-10K FT RANGE THIS AFTERNOON AND EVENING. ADDITIONAL RAIN AND REDUCED CIGS POSSIBLE FRIDAY. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE. BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED. && .SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ SHORT TERM/AVIATION...OUTLER LONG TERM...ADAIR 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
330 AM MDT THU MAY 14 2015 .SYNOPSIS... ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE. SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY. && .DISCUSSION... WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT. SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7 WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY. && .FIRE WEATHER... A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY... PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA. STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH. BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS... MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED. ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD. 43 && .AVIATION... 06Z TAF CYCLE VFR CONDITIONS TO PERSIST AT AREA TERMINALS...EXCEPT AT KROW WHERE IFR VSBYS IN FOG ARE POSSIBLE EARLY THURSDAY MORNING. SOME POTENTIAL FOR FOG DEVELOPMENT AT KTCC AS WELL...BUT FORECASTER CONFIDENCE TOO LOW TO INCLUDE IN TAF. OTHERWISE...LOOK FOR INCREASING SOUTHWEST LOW LEVEL FLOW THURSDAY WITH WINDY CONDITIONS BY AFTERNOON. HIGHEST GUSTS FORECAST AT KLVS THURSDAY AFTERNOON AROUND 36-38KTS. HIGH-BASED SHOWERS LIKELY NORTH WITH GUSTY WINDS MAY IMPACT KFMN AND KGUP LATE DAY. A FEW THUNDERSTORMS ARE POSSIBLE LATE DAY AS WELL...MAINLY NEAR THE TEXAS BORDER AND ACROSS THE NORTHEAST QUARTER...POSSIBLY IMPACTING KTCC. 11 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 74 44 61 41 / 20 30 30 50 DULCE........................... 69 40 57 35 / 30 30 40 70 CUBA............................ 70 43 59 35 / 20 10 40 60 GALLUP.......................... 71 38 59 35 / 10 10 30 50 EL MORRO........................ 66 36 56 35 / 5 10 30 60 GRANTS.......................... 71 38 61 33 / 5 10 30 40 QUEMADO......................... 68 37 60 38 / 5 10 20 50 GLENWOOD........................ 78 42 68 43 / 5 10 20 30 CHAMA........................... 64 33 53 31 / 30 30 40 70 LOS ALAMOS...................... 67 46 61 39 / 10 10 30 40 PECOS........................... 66 40 60 38 / 10 10 20 30 CERRO/QUESTA.................... 68 36 60 35 / 20 20 20 40 RED RIVER....................... 60 34 55 30 / 30 20 20 40 ANGEL FIRE...................... 61 35 56 30 / 20 20 20 40 TAOS............................ 68 38 61 35 / 20 10 20 40 MORA............................ 65 39 60 37 / 20 10 20 30 ESPANOLA........................ 73 40 65 43 / 10 10 20 30 SANTA FE........................ 70 39 62 40 / 10 10 20 40 SANTA FE AIRPORT................ 73 41 64 37 / 10 10 20 30 ALBUQUERQUE FOOTHILLS........... 74 44 64 46 / 10 10 20 30 ALBUQUERQUE HEIGHTS............. 77 49 67 44 / 5 5 20 20 ALBUQUERQUE VALLEY.............. 78 44 69 45 / 5 5 20 20 ALBUQUERQUE WEST MESA........... 77 45 69 44 / 10 5 20 20 LOS LUNAS....................... 77 47 71 42 / 5 5 20 20 RIO RANCHO...................... 77 48 68 44 / 10 5 20 30 SOCORRO......................... 79 50 73 46 / 5 10 10 10 SANDIA PARK/CEDAR CREST......... 71 43 66 39 / 10 10 20 30 TIJERAS......................... 73 43 68 42 / 10 10 20 30 MORIARTY/ESTANCIA............... 74 40 65 36 / 10 10 20 30 CLINES CORNERS.................. 70 42 64 37 / 10 10 20 30 GRAN QUIVIRA.................... 72 44 67 42 / 5 10 20 20 CARRIZOZO....................... 77 48 72 49 / 5 20 10 20 RUIDOSO......................... 73 47 69 41 / 10 20 10 30 CAPULIN......................... 74 43 67 42 / 5 20 5 20 RATON........................... 75 42 70 39 / 10 20 10 20 SPRINGER........................ 73 41 68 41 / 10 20 10 20 LAS VEGAS....................... 70 40 65 38 / 10 10 10 20 CLAYTON......................... 79 49 76 48 / 5 20 5 20 ROY............................. 76 47 71 44 / 10 20 10 20 CONCHAS......................... 77 49 76 51 / 10 10 5 20 SANTA ROSA...................... 80 50 78 47 / 10 10 5 20 TUCUMCARI....................... 84 53 81 51 / 10 20 5 20 CLOVIS.......................... 82 52 77 51 / 10 20 10 30 PORTALES........................ 84 53 79 55 / 10 20 10 40 FORT SUMNER..................... 84 52 80 51 / 10 20 5 20 ROSWELL......................... 86 54 83 52 / 10 20 5 30 PICACHO......................... 78 52 79 50 / 10 20 5 20 ELK............................. 72 51 73 48 / 10 20 10 20 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORMAN OK
1106 PM CDT WED MAY 13 2015 .AVIATION... 06Z TAFS... ANOTHER ROUND OF SHOWERS/STORMS WILL MOVE ACROSS THE AREA OVERNIGHT/EARLY THU. CEILINGS WILL GRADUALLY IMPROVE OVERNIGHT INTO THURSDAY. CEILINGS WILL THEN AGAIN LOWER THU EVENING AS NEXT SYSTEM APPROACHES. SHOWERS/STORMS WILL BE POSSIBLE AGAIN THU NIGHT. && .PREV DISCUSSION... /ISSUED 856 PM CDT WED MAY 13 2015/ UPDATE... MADE SOME ADJUSTMENTS TO THE PRECIP CHANCES THIS EVENING BASED ON LATEST RADAR TRENDS. THOUGHT ABOUT CANCELLING THE FLASH FLOOD WATCH... HOWEVER SOME OF THE HIGH RES MODELS KEEP THE CONVECTION IN SOUTHWEST MOVING ACROSS THE AREA OVERNIGHT. WITH ANTECEDENT CONDITIONS WOULD NOT TAKE MUCH ADDITIONAL RAINFALL TO CAUSE ADDITIONAL FLOODING. THEREFORE WILL KEEP WATCH GOING FOR NOW. OTHERWISE... NOT OTHER CHANGES AT THIS POINT. PREV DISCUSSION... /ISSUED 615 PM CDT WED MAY 13 2015/ AVIATION... 0Z TAFS... IFR/LIFR CEILINGS WILL CONT THIS EVENING. CEILINGSWILL LIKELY IMPROVE THURSDAY WITH EVERYONE EVENTUALLY AT MVFR/VFR LEVELS. RAIN... HEAVY AT TIMES WILL CONTINUE TO MOVE ACROSS THE REGION TONIGHT... GRADUALLY ENDING FROM WEST TO EAST. HOWEVER SOME LOWERED VISIBILITIES WILL BE POSSIBLE THROUGH THU MORNING. THUNDERSTORMS WILL ALSO BE POSSIBLE THIS EVENING. PREV DISCUSSION... /ISSUED 412 PM CDT WED MAY 13 2015/ DISCUSSION... PRIMARY PRECIPITATION SHIELD CONTINUES TO PIVOT EAST THROUGH CENTRAL AND EASTERN PORTIONS OF THE COUNTY WARNING AREA... ALTHOUGH CONVECTION IS REDEVELOPING IN THE TEXAS PANHANDLE AND WEST TEXAS WHICH MAY MOVE INTO WESTERN PORTIONS OF THE AREA THIS AFTERNOON AND EVENING AGAIN. HRRR AND OUNWRF SHOW THAT THIS MAY PERSIST FOR A WHILE THIS EVENING IN WESTERN OKLAHOMA/NORTH TEXAS BUT LIMITED INSTABILITY SHOULD PREVENT STORMS WIDESPREAD STORMS. OVERALL... STILL EXPECT GENERAL DECREASE IN PRECIPITATION FROM WEST TO EAST OVERNIGHT AND EARLY TOMORROW MORNING AS SHORTWAVE MOVES NORTHEAST PAST THE AREA. FLASH FLOOD WATCH STILL LOOKS GOOD AS THE MODERATE RAINFALL CAN STILL CAUSE FLOODING ISSUES BECAUSE OF THE HEAVY RECENT RAINFALL. STORMS EXPECTED AGAIN THURSDAY NIGHT INTO FRIDAY WITH MOISTURE INCREASE AND PERHAPS A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE PRIMARY UPPER TROUGH APPROACHES AND INCREASES POPS SIGNIFICANTLY FRIDAY NIGHT AND SATURDAY. DECENT SIGNAL OF A COMPLEX DEVELOPING WEST AND MOVING INTO THE AREA SATURDAY MORNING WITH REDEVELOPMENT EXPECTED AGAIN ON SATURDAY. THERE ARE STILL SOME QUESTIONS ON THE EXPECTED EVOLUTION ON SATURDAY... BUT STILL WILL BE LOOKING AT THE SEVERE WEATHER POTENTIAL FOR SATURDAY AS WE GET CLOSER. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 60 80 65 79 / 70 20 30 40 HOBART OK 58 80 62 81 / 70 10 40 30 WICHITA FALLS TX 61 82 65 82 / 40 10 40 40 GAGE OK 55 83 60 82 / 40 10 30 20 PONCA CITY OK 58 80 65 80 / 80 30 20 30 DURANT OK 63 81 66 79 / 50 40 30 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR OKZ007-008-012-013- 017>020-022>048-050>052. TX...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR TXZ083>090. && $$ 30/25/25
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
341 AM MDT THU MAY 14 2015 .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 300 AM MDT THU MAY 14 2015 FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LLVL MOISTURE IS NOT ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z. UPPER LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE EJECTS NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER CALIFORNIA. WITH GOOD MIDLVL ISENTROPIC ASCENT AND SOME ELEVATED CAPE...THIS IS ACTUALLY A SITUATION WHERE SHOWER AND TSTM COVERAGE COULD BE GREATER INTO THE NIGHT...ESPECIALLY OVER THE NORTHEASTERN HALF OF THE CWA. THUS...KEPT THE 30-40 POPS GOING THROUGH EARLY FRI MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE TO ADVECT HIGHER DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT. THE MOST IMPACTFUL EVENT IN THE SHORT TERM IS STILL LOOKING LIKE THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI. OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS THIS WOULD PUSH THE SVR THREAT INTO SOUTHEAST WY. WHILE LARGE HAIL WOULD LIKELY BE THE PRIMARY THREAT...THE LLVL SHEAR PARAMETERS DO SHOW THE POTENTIAL FOR SOME WEAK TORNADOES ESPECIALLY ALONG AND JUST NORTH OF THE WARM FRONT WHERE WINDS WILL BE BACKED THE MOST. NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3 KM HELICITY OF 250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2 SPC OUTLOOK HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A SLIGHT RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO NORTH PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE SFC LOW AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE A BIT LESS LLVL MOISTURE AND INSTABILITY TO WORK WITH ON SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A COLD FRONT PUSHING ACROSS THE REGION. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 300 AM MDT THU MAY 14 2015 AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG /NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LLVL UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LLVL FORCING BENEATH INCREASINGLY DIFLUENT FLOW ALOFT AND A COUPLED H25 JET. THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM ADVECTION IN LLVL EASTERLY/UPSLOPE FLOW MAKES THIS QUESTIONABLE AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO SEE PCPN CHANGE TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST FOR HIGHER ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST VIRTUALLY EVERY DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES EACH AFTN THROUGH WED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 214 AM MDT THU MAY 14 2015 AMENDED AVIATION DISCUSSION FOR 06Z TAFS. AREAS OF FOG ARE NOW DEVELOPING OVER THE WESTERN NE PANHANDLE...WITH IFR CIGS/VSBYS OVER SEVERAL TERMINALS. THE HRRR SHOWS THIS CONTINUING THROUGH AT LEAST SUNRISE...LINGERING A BIT LONGER AT KAIA. VFR CONDITIONS ARE EXPECTED OVER SOUTHEAST WYOMING SITES. SHOWERS AND TSTMS ARE STILL EXPECTED ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT. && .FIRE WEATHER... ISSUED AT 300 AM MDT THU MAY 14 2015 NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO 25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL GREEN UP AFTER THE RECENT WET PERIOD. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...CLH AVIATION...CLH FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
216 AM MDT THU MAY 14 2015 .UPDATE... ISSUED AT 906 PM MDT WED MAY 13 2015 AS OUR AFTERNOON FORECAST TEAM PREDICTED...SHOWERS HAVE DECREASED CONSIDERABLY IN AREAL COVERAGE. BASED ON TRENDS AND 00Z MODEL GUIDANCE...WILL MAINTAIN LOW CHANCES FOR PRECIPITATION THE REST OF THE NIGHT. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 400 PM MDT WED MAY 13 2015 SHORTWAVE ENERGY AND UPPER LEVEL JET MAX WILL CONTINUE TO LIFT NORTHEAST OUT OF THE FORECAST AREA THIS EVENING WITH MOST SHOWER ACTIVITY ENDING WEST OF THE SHORTWAVE AND JET. A FEW SHOWERS MAY LINGER PAST 9 PM BUT MOST ACTIVITY SHOULD HAVE ENDED BY THAT TIME. TO THE WEST OF THE LARAMIE RANGE SHOWER ACTIVITY IS LARGELY BEING DRIVEN BY INSTABILITY. THIS AREAS OF SHOWER ACTIVITY WILL ALSO TAPER OFF THIS EVENING. SUBSIDENCE WILL ALLOW SET IN THIS EVENING AS A RIDGE BUILDS OVER THE NORTHERN ROCKIES. SKIES WILL CLEAR AND WINDS WILL BE ON THE LIGHT SIDE TONIGHT. SOME POCKETS OF RADIATION FOG MAY DEVELOP LATE TONIGHT. NOT EXPECTING LARGE IMPACTS FROM ANY FOG TONIGHT THAT MIGHT FORM BUT IT WILL BE SOMETHING TO KEEP AN EYE ON LATE TONIGHT...MAINLY WEST OF THE LARAMIE RANGE. A BROAD WEST COAST TROUGH WILL BEGIN TO PUSH INTO THE ROCKIES LATE TOMORROW AS THE RIDGE AXIS SHIFTS INTO THE PLAINS. A FEW SHOWERS AND THUNDERSTORMS WILL DEVELOP THURSDAY AFTERNOON. THE SET UP IS NOT SUPPORTIVE OF SEVERE THUNDERSTORMS BUT A FEW MARGINAL STORMS NOT COMPLETELY QUESTION NEAR THE LARAMIE RANGE LATE AFTERNOON. UPPER LEVEL ENERGY WITH ISENTROPIC FORCING WILL KEEP CHANCES FOR SHOWERS AND A FEW THUNDERSTORMS GOING INTO THURSDAY NIGHT BUT THE MAIN CHANCES FOR PRECIPITATION WILL HOLD OFF UNTIL FRIDAY. WILL NEED TO KEEP A CLOSE EYE ON SEVERE THUNDERSTORM POTENTIAL INTO THE PLAINS FRIDAY. THERE IS STILL A LOT OF UNCERTAINLY IN THE PLACEMENT OF A WARM FRONT AND TIMING OF COLD FRONT FRIDAY. MODELS ARE SHOWING A LOT OF ELEVATED CAPE AND ENOUGH SHEAR FOR SUPERCELL THUNDERSTORMS. NORTH OF THE WARM FRONT LARGE HAIL WILL BE THE MAIN SEVERE THUNDERSTORM THREAT BUT ALONG AND CLOSE TO THE SURFACE WARM FRONT THERE WILL LIKELY BE AN ELEVATED TORNADO THREAT. WILL CONTINUE TO MONITOR MODEL CHANGES BUT AT THIS TIME IT LOOKS AT THROUGH THE SURFACE FRONT WILL EXTEND ACROSS THE NORTHERN NEBRASKA PANHANDLE FRIDAY AFTERNOON. .LONG TERM...SATURDAY THROUGH TUESDAY... ISSUED AT 400 PM MDT WED MAY 13 2015 MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT WITH LARGELY MERIDIONAL FLOW ALOFT THROUGH THE PERIOD. THIS SHOULD RESULT IN A FAIRLY ACTIVE WEATHER PERIOD FOR SOUTHEAST WYO AND THE WESTERN NEB PANHANDLE THRU THE WEEKEND AND INTO EARLY NEXT WEEK. THE WEEKEND STILL APPEARS TO BE RATHER WET WITH A COMPLEX NEGATIVELY TILTED SHORTWAVE MOVING EAST ONTO THE PLAINS ON SAT. BOTH THE GFS AND ECMWF BRING AN ASSOCIATED DOUBLE-BARRELED SURFACE LOW INTO SD/NE...WITH WRAPAROUND PCPN LIKELY SPREADING ACROSS THE CWA. WEAK CAPES SUGGEST CONVECTION WILL BE AT A MINIMUM...BUT COOL AIR ALOFT MAY YIELD ENOUGH INSTABILITY FOR A FEW LIGHTNING STRIKES AND POSSIBLY SMALL HAIL. THERE IS SOME POTENTIAL FOR ACCUMULATING SNOWFALL IN THE HIGH MOUNTAINS ABOVE 9K FEET ON SAT AND SUN WITH FAVORABLE OROGRAPHICS AND H7 TEMPS FALLING TO -2 DEG C OR LOWER PER THE ECMWF. EXPECT THIS TO BE SUB-ADVISORY. A TRANSITORY RIDGE PROVIDES A BRIEF BREAK ON SUN NIGHT INTO MON BEFORE STRONG SW FLOW ALOFT INCREASES AGAIN AHEAD OF THE NEXT SYSTEM OVER SOUTHERN CALIFORNIA. SOME DIFFERENCES IN MODEL QPF/PCPN COVERAGE HEADING INTO TUES...WITH THE ECMWF SHOWING MUCH MORE WIDESPREAD SHOWERS AND TSTMS WITH LLVL UPSLOPE DEVELOPING ALONG THE LARAMIE RANGE. THE GFS TURNS WINDS WESTERLY/DOWNSLOPE AS IT MOVES THE SURFACE TROUGH QUICKLY INTO WESTERN NEB. INCREASED POPS ABOVE GUIDANCE WITH BOTH THE GFS AND ECM SHOWING STRONG UPPER DIFFLUENCE. WOULD TEND TO LEAN TOWARD THE ECMWF WITH SOUTHERLY MID/UPPER-LEVEL FLOW KEEPING THE SURFACE FEATURE TIED TO THE LARAMIE RANGE AS WELL. BOTH MODELS SUGGEST UPWARDS OF 1500 J/KG OF CAPE ON THE EAST SIDE OF THE BOUNDARY...SO THE POTENTIAL FOR STRONG CONVECTION SHOULD BE ON THE UPTICK COME TUE AFTN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 214 AM MDT THU MAY 14 2015 AMENDED AVIATION DISCUSSION FOR 06Z TAFS. AREAS OF FOG ARE NOW DEVELOPING OVER THE WESTERN NE PANHANDLE...WITH IFR CIGS/VSBYS OVER SEVERAL TERMINALS. THE HRRR SHOWS THIS CONTINUING THROUGH AT LEAST SUNRISE...LINGERING A BIT LONGER AT KAIA. VFR CONDITIONS ARE EXPECTED OVER SOUTHEAST WYOMING SITES. SHOWERS AND TSTMS ARE STILL EXPECTED ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT. && .FIRE WEATHER... ISSUED AT 331 PM MDT WED MAY 13 2015 CONDITIONS WILL REMAIN ON THE COOL SIDE OF AVERAGE OVER THE NEXT 7 DAYS AS AN ACTIVE WEATHER PATTERN REMAINS IN PLACE. THERE WILL BE A CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS SEVERAL DAYS DURING THIS PERIOD. THERE ARE NO CRITICAL FIRE CONCERNS. && .HYDROLOGY... ISSUED AT 331 PM MDT WED MAY 13 2015 THE LARAMIE RIVER NEAR LARAMIE WILL CONTINUE TO RUN HIGH THE NEXT SEVERAL DAYS...BUT ASSUMING FORECAST PRECIPITATION AMOUNTS ARE CLOSE TO CORRECT...THEN THE RIVER WILL REMAIN BELOW FLOOD STAGE. TEMPERATURES WILL REMAIN AT TO BELOW NORMAL OVER THE NEXT WEEK...SO AS LONG AND STRONG THUNDERSTORMS DO NOT OCCUR OVER THE MOUNTAINS...SNOW PACK WILL SLOWLY COME OFF THE MOUNTAINS WITH NO BIG CONCERNS FOR RIVER FLOODING OVER THE NEXT WEEK. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...RUBIN SHORT TERM...SML LONG TERM...CAH AVIATION...CLH FIRE WEATHER...SML HYDROLOGY...SML
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
433 AM PDT THU MAY 14 2015 .SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK. COOLER THAN NORMAL TEMPERATURES WILL CONTINUE. && .DISCUSSION...AS OF 3:00 AM PDT THURSDAY...KMUX RADAR THIS MORNING IS STARTING TO PICK UP THE LEADING EDGE OF PRECIPITATION FROM A SYSTEM OFF OUR COAST. CLOSEST ECHOES AROUND ABOUT 70 MILES TO THE WEST OF MONTEREY WITH MORE SUBSTANTIAL RETURNS ABOUT 75 MILES WEST OF BIG SUR. THIS VERIFIES WELL WITH THE LATEST RUN OF THE HRRR. MODELS ARE GENERALLY IN GOOD AGREEMENT THAT RAIN WILL CONTINUE TO ADVANCE TO THE COAST THIS MORNING AND BE NEAR LOCAL BEACHES BY MID TO LATE MORNING. BY EARLY AFTERNOON RAIN IS EXPECTED TO BE ACROSS OUR ENTIRE AREA. RAIN WILL ALSO CHANGE OVER TO SHOWERS BY AFTERNOON AS THE ATMOSPHERE BECOMES MORE UNSTABLE. LIFTED VALUES DROP AS LOW AS MINUS 2 ALONG WITH SOME WEAK CAPE NUMBERS SO THUNDERSTORMS AND SMALL HAIL CANNOT BE RULED OUT. RAINFALL AMOUNTS ARE STILL EXPECTED TO BE HIGHER THE FARTHER TO THE SOUTH YOU TRAVEL WITH THE HIGHEST VALUES FOR COASTAL MONTEREY COUNTY MOUNTAINS. THERE HALF AN INCH TO AN INCH COULD EASILY FALL. FOR THE REST OF OUR AREA...MANY PLACES WILL LIKELY SEE A TENTH TO A QUARTER OF AN INCH. INTERESTING TO NOTE OFF THE HRRR THAT IT INDICATES SOME POCKETS OF HALF AN INCH TO THE EAST BY BY THE AFTERNOON. AS IS ALWAYS THE CASE WITH SHOWERS...WE WILL LIKELY SEE A FEW SPOTS GETTING MUCH MORE THAN EXPECTED WHILE OTHER PLACES GET LITTLE TO NO RAINFALL. SHOWERS WILL LINGER INTO THE OVERNIGHT HOURS AND SLOWLY DIMINISH THROUGH FRIDAY. SYNOPTICALLY THE SYSTEM THAT WILL PROVIDE THE RAIN IS ASSOCIATED WITH A LONGWAVE TROF THAT IS DIVING SOUTHWARD OFF THE WEST COAST. BASED OFF THE TRACK OF THE PARENT LOW ASSOCIATED WITH THE TROF THE NEXT ROUND OF RAIN WILL FOCUS WELL TO OUR SOUTH. PERSONS WHO HAVE TRAVEL PLANS TO SOUTHERN CALIFORNIA ON FRIDAY SHOULD PAY VERY CLOSE ATTENTION TO THE LATEST FORECASTS. A MIX OF SUN AND CLOUDS ALONG WITH COOLER THAN NORMAL TEMPERATURES WILL LIKELY GO THROUGH THE WEEKEND INTO ALL OF NEXT WEEK AS A BROAD LONGWAVE TROF REMAINS ACROSS OUR ENTIRE REGION. MULTIPLE DISTURBANCES WILL ROTATE THROUGH THE TROF ALTHOUGH THE VAST MAJORITY OF ASSOCIATED RAINFALL WITH LIKELY STAY WELL OUT OF OUR CWA. ON THE FLIP SIDE...THE UNSETTLED PATTERN WILL HELP TO LIMIT THE MARINE LAYER. && .AVIATION...AS OF 4:30 AM PDT THURSDAY...CLOUDS ARE LOWERING WITH THE APPROACH OF AN UPPER LEVEL LOW. RADAR IS STARTING TO DETECT LIGHT SHOWERS OFF THE COAST AND THESE WILL MOVE INTO THE COAST BY MIDMORNING AND INLAND LATE MORNING. WINDS WILL BE LIGHT SOUTHERLY THIS MORNING BUT WILL SWITCH TO WESTERLY IN THE AFTERNOON. VICINITY OF KSFO...MVFR CIGS. SHOWERS AFTER 16Z. SOUTHEAST WINDS 5-10 KT SWITCHING TO THE WEST AFTER 20Z. CLOUDS DECREASING AFTER 02Z. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...MVFR CIGS. SHOWERS AFTER 15Z. CLOUDS DECREASING AFTER 01Z. && .MARINE...AS OF 4:30 AM PDT THURSDAY...A 1010 MB LOW OFF THE NORTHERN CALIFORNIA COAST WILL TRACK SOUTHWARD BRINGING A SLIGHT CHANCE OF THUNDERSTORMS TODAY AND TONIGHT. NORTHWEST WINDS WILL INCREASE FRIDAY AND SATURDAY AS THE LOW MOVES INLAND OVER SOUTHERN CALIFORNIA AND HIGH PRESSURE BUILDS OFF THE CALIFORNIA COAST. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: BELL AVIATION/MARINE: W PI 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 SAN FRANCISCO BAY AREA
259 AM PDT THU MAY 14 2015 .SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK. COOLER THAN NORMAL TEMPERATURES WILL CONTINUE. && .DISCUSSION...AS OF 3:00 AM PDT THURSDAY...KMUX RADAR THIS MORNING IS STARTING TO PICK UP THE LEADING EDGE OF PRECIPITATION FROM A SYSTEM OFF OUR COAST. CLOSEST ECHOES AROUND ABOUT 70 MILES TO THE WEST OF MONTEREY WITH MORE SUBSTANTIAL RETURNS ABOUT 75 MILES WEST OF BIG SUR. THIS VERIFIES WELL WITH THE LATEST RUN OF THE HRRR. MODELS ARE GENERALLY IN GOOD AGREEMENT THAT RAIN WILL CONTINUE TO ADVANCE TO THE COAST THIS MORNING AND BE NEAR LOCAL BEACHES BY MID TO LATE MORNING. BY EARLY AFTERNOON RAIN IS EXPECTED TO BE ACROSS OUR ENTIRE AREA. RAIN WILL ALSO CHANGE OVER TO SHOWERS BY AFTERNOON AS THE ATMOSPHERE BECOMES MORE UNSTABLE. LIFTED VALUES DROP AS LOW AS MINUS 2 ALONG WITH SOME WEAK CAPE NUMBERS SO THUNDERSTORMS AND SMALL HAIL CANNOT BE RULED OUT. RAINFALL AMOUNTS ARE STILL EXPECTED TO BE HIGHER THE FARTHER TO THE SOUTH YOU TRAVEL WITH THE HIGHEST VALUES FOR COASTAL MONTEREY COUNTY MOUNTAINS. THERE HALF AN INCH TO AN INCH COULD EASILY FALL. FOR THE REST OF OUR AREA...MANY PLACES WILL LIKELY SEE A TENTH TO A QUARTER OF AN INCH. INTERESTING TO NOTE OFF THE HRRR THAT IT INDICATES SOME POCKETS OF HALF AN INCH TO THE EAST BY BY THE AFTERNOON. AS IS ALWAYS THE CASE WITH SHOWERS...WE WILL LIKELY SEE A FEW SPOTS GETTING MUCH MORE THAN EXPECTED WHILE OTHER PLACES GET LITTLE TO NO RAINFALL. SHOWERS WILL LINGER INTO THE OVERNIGHT HOURS AND SLOWLY DIMINISH THROUGH FRIDAY. SYNOPTICALLY THE SYSTEM THAT WILL PROVIDE THE RAIN IS ASSOCIATED WITH A LONGWAVE TROF THAT IS DIVING SOUTHWARD OFF THE WEST COAST. BASED OFF THE TRACK OF THE PARENT LOW ASSOCIATED WITH THE TROF THE NEXT ROUND OF RAIN WILL FOCUS WELL TO OUR SOUTH. PERSONS WHO HAVE TRAVEL PLANS TO SOUTHERN CALIFORNIA ON FRIDAY SHOULD PAY VERY CLOSE ATTENTION TO THE LATEST FORECASTS. A MIX OF SUN AND CLOUDS ALONG WITH COOLER THAN NORMAL TEMPERATURES WILL LIKELY GO THROUGH THE WEEKEND INTO ALL OF NEXT WEEK AS A BROAD LONGWAVE TROF REMAINS ACROSS OUR ENTIRE REGION. MULTIPLE DISTURBANCES WILL ROTATE THROUGH THE TROF ALTHOUGH THE VAST MAJORITY OF ASSOCIATED RAINFALL WITH LIKELY STAY WELL OUT OF OUR CWA. ON THE FLIP SIDE...THE UNSETTLED PATTERN WILL HELP TO LIMIT THE MARINE LAYER. && .AVIATION...AS OF 10:53 PM PDT WEDNESDAY...A MIX OF LOW, MID AND HIGH CLOUDS WILL CONTINUE TO MOVE ACROSS THE REGION WITH AN INCREASING CHANCE OF RAIN LATE TONIGHT INTO EARLY THURSDAY MORNING. A FRONTAL BAND ASSOCIATED WITH THE APPROACHING LOW WILL ARRIVE PARALLEL TO THE COAST THEN SWEEP ACROSS THE REGION THURSDAY MORNING BRINGING RAIN TO THE ENTIRE AREA. WET RUNWAYS ARE POSSIBLE AFTER 12Z THURSDAY. VICINITY OF KSFO...VFR CIGS WILL LOWER TO AROUND 3000 FEET OVERNIGHT WITH RAIN CHANCES INCREASING AFTER 12Z TONIGHT. LIGHT SOUTHWESTERLY WINDS OF 5 TO 10 KT EXPECTED THROUGH LATE TONIGHT. WINDS WILL TURN SOUTHERLY OVERNIGHT INTO THURSDAY. WET RUNWAYS POSSIBLE AFTER 12Z. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CIGS WILL LOWER TO AROUND 2500 FEET OVERNIGHT WITH RAIN CHANCES INCREASING AFTER 15Z TONIGHT. LIGHT SOUTHWESTERLY WINDS OF 5 TO 10 KT EXPECTED THROUGH LATE TONIGHT. WINDS WILL TURN SOUTHERLY OVERNIGHT INTO THURSDAY. WET RUNWAYS POSSIBLE AFTER 15Z. && .MARINE...AS OF 9:07 PM PDT WEDNESDAY...LIGHT SOUTHERLY WINDS WILL CONTINUE TONIGHT AS A LOW PRESSURE SYSTEM APPROACHES THE AREA. A SLIGHT CHANCE OF THUNDERSTORMS EXISTS THURSDAY AS THIS STORM MOVES ACROSS THE COASTAL WATERS. STRONGER NORTHWEST WINDS RETURN LATE IN THE WEEK AND INTO THE WEEKEND AS HIGH PRESSURE REDEVELOPS OVER THE REGION. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: BELL AVIATION/MARINE: CW 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 TAUNTON MA
1003 AM EDT THU MAY 14 2015 .SYNOPSIS... LARGE HIGH PRESSURE WILL BUILD ACROSS THE EASTERN U.S. WITH DRIER WEATHER THROUGH THE REMAINDER OF THIS WEEK. AN UPPER LEVEL DISTURBANCE WILL BRING SHOWERS TO THE REGION FRIDAY NIGHT AND SATURDAY. A BACK DOOR COLD FRONT USHERS IN COOLER AIR SUNDAY THROUGH THE BEGINNING OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM UPDATE... MINOR CHANGES TO THE FORECAST. WENT WITH A HRRR / RAP BLEND FOR THE NEXT 12-HOURS WITH RESPECT TO TEMPERATURES / DEWPOINTS / WIND THAT NETS HIGHS AROUND THE UPPER-60S TO LOW-70S WITH MINIMUM RELATIVE HUMIDITY VALUES DOWN AROUND 20-PERCENT. HIGH PRESSURE IN CONTROL RESULTING IN LIGHT WINDS WHICH WILL ALLOW SEABREEZES TO COME ASHORE BY MIDDAY...PUSHING INTO THE EASTERN- INTERIOR BY EVENING. WINDS OVERALL REMAINING LIGHT...EXPECTING THE STRONGEST ALONG THE COASTS WITH ONSHORE FLOW...GUSTS AROUND 15 MPH POSSIBLE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... TONIGHT... ANOTHER GOOD RADIATIONAL COOLING NIGHT WITH LIGHT WINDS AND CLEAR SKIES AS HIGH PRES REMAINS IN CONTROL. MINS WILL LIKELY DROP INTO THE MID/UPPER 30S WITH PATCHY FROST IN THE NORMALLY COLDER LOCATIONS IN W MA AND INTERIOR E MA AND FROST ADVISORIES MAY BE NEEDED AGAIN. ELSEWHERE LOWS WILL BE MOSTLY IN THE 40S. FRIDAY... HIGH PRES WILL BE S OF NEW ENG WITH DEVELOPING SW FLOW BRINGING MILDER AIR TO SNE. 850 MB TEMPS WARMING TO 7-8C WHICH TRANSLATES TO HIGHS IN THE LOW TO MID 70S...BUT COOLER ALONG THE COAST WHERE SEABREEZES LIKELY AGAIN. SUNSHINE WILL GIVE WAY TO INCREASING HIGH CLOUDS IN THE AFTERNOON. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * RAIN LATE FRI INTO THE WEEKEND WITH SHORTWAVE * BACK DOOR COLD FRONT WILL BRING COOLER TEMPERATURES SUN AND MON * COLD FRONT MAY BRING ANOTHER ROUND OF SHOWERS TOWARDS MIDWEEK MODELS ARE IN DECENT AGREEMENT THROUGH THE LONG TERM PERIOD. AS WE MOVE INTO THE WEEKEND SHORTWAVE WILL MOVE THROUGH SOUTHERN NEW ENGLAND BRINGING RAIN SHOWERS TO THE REGION. AN UPPER LEVEL RIDGE THEN BUILDS OVER THE REGION AND A BACK DOOR COLD FRONT WILL MOVE INTO SOUTHERN NEW ENGLAND SUNDAY. THE EXACT TIMING AND SOUTHWESTWARD EXTENT OF THE FRONT IS IN QUESTION WITH THE ECMWF BRINGING IT MUCH FARTHER SOUTHWEST THAN THE GFS. THIS WILL MAKE A BIG DIFFERENCE IN HIGH TEMPERATURES. BEYOND THE BACK DOOR COLD FRONT...THERE ARE TIMING DISCREPANCIES AMONGST THE MODELS. FRIDAY NIGHT AND SATURDAY...THIS PERIOD LOOKS TO HAVE SOME RAIN SHOWERS AS A SHORTWAVE DISTURBANCE MOVES OVER SOUTHERN NEW ENGLAND. THERE IS SOME MODEST INSTABILITY DURING THIS TIME FRAME AS INDICATED BY K INDICES ABOVE 30 AND NEGATIVE SHOWALTER INDICES. THIS COULD RESULT IN SOME ISOLATED THUNDER WITH THESE SHOWERS. SUNDAY...A BACK DOOR COLD FRONT WILL PUSH INTO SOUTHERN NEW ENGLAND...BRINGING AN END TO THE RAIN SHOWERS. AS MENTIONED ABOVE...THE WESTWARD EXTENT OF THIS FRONT DEPENDS ON THE MODEL MAKING TEMPERATURE FORECASTS DIFFICULT. EXPECT SUNDAY TO BE A DRY DAY WITH CHILLY NORTHEAST WINDS ALONG THE EAST COAST AND PARTICULARLY ACROSS NORTHEASTERN MASSACHUSETTS. TEMPERATURE FORECAST IS LOW CONFIDENCE...PARTICULARLY ACROSS EASTERN MASS AND RHODE ISLAND. MONDAY THROUGH WEDNESDAY...THERE ARE TIMING DISCREPANCIES AMONGST THE MODELS BUT THE OVERALL PATTERN IS SIMILAR BETWEEN THE SOLUTIONS. THE UPPER RIDGE OVER NEW ENGLAND WILL WEAKEN AND GRADUALLY MOVE OFFSHORE LATE MONDAY INTO TUESDAY. THEN LOW PRESSURE MOVING THROUGH QUEBEC WILL BRING A COLD FRONT THROUGH SOUTHERN NEW ENGLAND TUESDAY OR WEDNESDAY ALLOWING FOR ANOTHER CHANCE OF SHOWERS. TEMPERATURES WILL BE RIGHT AROUND NORMAL DURING THIS TIME FRAME. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE. THROUGH FRIDAY...VFR. ONSHORE SEABREEZES DEVELOPING AROUND 15Z. KBOS TAF...HIGH CONFIDENCE IN TAF. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY... FRIDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE. MAINLY VFR. PERIODS OF MVFR/IFR IN SCATTERED SHOWERS AND FOG. SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR CONDITIONS BEHIND BACK DOOR COLD FRONT. MONDAY...HIGH CONFIDENCE. VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE. TODAY THROUGH FRIDAY...HIGH PRES WILL BRING QUIET BOATING WEATHER WITH LIGHT WINDS AND SEAS AND GOOD VSBYS. WINDS WILL BECOME ONSHORE 10-15 KTS OVER NEARSHORE WATERS TODAY AND AGAIN FRI AS SEABREEZES DEVELOP. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY... FRIDAY NIGHT AND SATURDAY...LOW CONFIDENCE. WHILE CONDITIONS ARE CURRENTLY EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA...WINDS AND SEAS WILL BE INCREASING AS A COLD FRONT APPROACHES THE WATERS. 5 FOOT SEAS IN PARTICULAR ARE NOT OUT OF THE QUESTION FOR THE OUTER WATERS. SUNDAY AND MONDAY...MAINLY QUIET BOATING WEATHER AS HIGH PRESSURE BUILDS SOUTH OVER THE WATERS. NORTHEASTERLY WINDS SUNDAY WILL GRADUALLY BECOME LIGHT AND VARIABLE. && .FIRE WEATHER... TODAY AND FRIDAY...DRY WEATHER CONDITIONS WILL CONTINUE WITH MINIMUM RH VALUES AWAY FROM THE IMMEDIATE COAST DROPPING TO UPPER TEENS TO 20S TODAY AND 20-30 PERCENT FRIDAY. SINCE HIGH PRESSURE WILL BE OVERHEAD...WINDS WILL BE LIGHT WITH SPEEDS LESS THAN 15 MPH. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...FROST ADVISORY FROM 2 AM TO 7 AM EDT FRIDAY FOR MAZ002-003-008- 010. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/RLG NEAR TERM...KJC/RLG/SIPPRELL SHORT TERM...KJC LONG TERM...RLG AVIATION...KJC/RLG MARINE...KJC/RLG FIRE WEATHER...WFO BOX STAFF
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
1002 AM EDT THU MAY 14 2015 .UPDATE... ANOTHER WARM AND MUGGY DAY EXPECTED ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA. EARLY MORNING VISIBLE SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES THIS MORNING WITH ONLY A FEW HIGH CLOUDS PRESENT ACROSS THE AREA. WITH MOSTLY CLEAR SKIES...TEMPS WILL WARM QUICKLY INTO THE MIDDLE/UPPER 80S BEFORE ULTIMATELY TOPPING OUT IN THE LOWER 90S FOR MUCH OF THE AREA...SLIGHTLY COOLER ALONG THE IMMEDIATE COAST. AS FAR AS RAIN CHANCES ARE CONCERNED...THE OVERALL SETUP FOR TODAY LOOKS SIMILAR TO YESTERDAY. WITH DECENT SE/E FLOW IN PLACE IN THE LOWER LEVELS WEST COAST SEA BREEZE WILL LIKELY HAVE A DIFFICULT TIME PENETRATING TOO FAR INLAND TODAY. LOCAL HI-RES MODELS SUPPORT THIS THINKING OF A LIKELY SEA BREEZE COLLISION NEAR THE I-75 CORRIDOR. MOST RECENT HRRR RUN IS NOT VERY ROBUST WITH OVERALL PRECIP COVERAGE NOR ARE RECENT RUNS OF CONVECTION ALLOWING MODELS SO MAINTAINING POPS IN THE 30 TO 50 RANGE FOR THE AREA...HIGHEST NEAR AND WEST OF I-75...SEEMS REASONABLE. ONLY MADE A FEW MINOR ADJUSTMENTS FOR THE MORNING UPDATE. && .AVIATION... VFR CONDITIONS EXPECTED TO PREVAIL THIS MORNING AND INTO THE AFTERNOON. EASTERLY FLOW THROUGH THE MORNING HOURS WILL GIVE WAY TO AN AFTERNOON WEST COAST SEA BREEZE FOR COASTAL TERMINALS. VCTS DEVELOPING DURING THE LATE AFTERNOON HOURS WILL AFFECT TAFS SITES INTO THE EVENING BEFORE STORM COVERAGE DISSIPATES AFTER SUNSET. LOCALIZED MVFR/IFR RESTRICTIONS WILL BE POSSIBLE WITH ANY THUNDERSTORMS BUT WILL NOT INCLUDE ANY TEMPOS AT THIS TIME. && .MARINE... SURFACE RIDGING CENTERED WELL NORTH OF THE AREA WILL HELP MAINTAIN GENERALLY EASTERLY FLOW. EXPECT A SEA BREEZE CIRCULATION TO DEVELOP EACH AFTERNOON NEAR THE COAST WITH A NOCTURNAL EASTERLY SURGE THROUGH THE WEEKEND. SCATTERED SHOWERS AND STORMS NEAR THE COAST ARE EXPECTED TO SHIFT INTO THE NEAR AND OFF SHORE WATERS DURING THE LATE EVENING HOURS AS THE LAND BREEZE DEVELOPS. NO CHANGES NEEDED FOR THE MORNING UPDATE. && .PRELIMINARY POINT TEMPS/POPS... TPA 90 73 89 72 / 50 40 50 50 FMY 91 71 91 71 / 40 20 40 30 GIF 91 71 90 71 / 40 10 50 10 SRQ 89 71 88 71 / 50 40 50 50 BKV 91 70 88 69 / 50 20 50 20 SPG 90 75 89 75 / 40 40 50 50 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/AVIATION/FIRE WEATHER/MARINE...11/MCKAUGHAN DECISION SUPPORT...14/MROCZKA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
953 AM CDT THU MAY 14 2015 .UPDATE... ISSUED AT 952 AM CDT THU MAY 14 2015 SHOWERS IN WEST CENTRAL ILLINOIS HAVE BEEN STRUGGLING TO MAKE ANY EASTWARD PROGRESS. OUR MORNING SOUNDING SHOWED VERY DRY AIR BELOW 15000 FEET...AND CEILINGS UNDERNEATH THE RAIN SHIELD ARE STRUGGLING TO GET MUCH BELOW 7000 FEET. RAP FORECAST SOUNDINGS KEEP IT PRETTY DRY BELOW 850 MB INTO THE AFTERNOON AND FOCUS MUCH OF THE RAIN ALONG AND WEST OF THE ILLINOIS RIVER. THIS WOULD BE ASSOCIATED WITH THE SHOWERS THAT ARE CURRENTLY STEADILY MOVING THROUGH CENTRAL AND SOUTHWEST MISSOURI. THE RADAR ECHOES MOVING OUT OF SOUTHWEST ILLINOIS ARE ALSO VERY LIGHT...AND THESE WILL BE MOVING INTO THE SOUTHEAST PART OF THE FORECAST AREA SHORTLY AFTER MIDDAY. HAVE SENT SOME UPDATED ZONES/GRIDS TO MAINLY REFINE THE RAIN TRENDS. && .SHORT TERM...(TODAY) ISSUED AT 319 AM CDT THU MAY 14 2015 1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE. .LONG TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 319 AM CDT THU MAY 14 2015 UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A CHANCE OF THUNDER ACROSS THE BOARD TONIGHT. ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE 60S. WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE MAY NEED TO BE REMOVED BY LATER SHIFTS. ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS DIPPING INTO THE 40S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 600 AM CDT THU MAY 14 2015 VFR CONDITIONS ARE EXPECTED THRU THE DAY WITH POSSIBLE MVFR CIGS AFTER 04Z TONIGHT AS A WARM FRONT LIFTS TOWARDS THE AREA. A LARGE AREA OF LIGHT RAIN WAS MAKING SLOW PROGRESS TO THE EAST AS IT ENCOUNTERS SOME VERY DRY AIR AT THE LOW LEVELS OF THE ATMOSPHERE. LATEST RAP FORECAST SOUNDINGS INDICATING CIGS WILL GRADUALLY LOWER AS THE MOISTURE WORKS ITS WAY INTO OUR AREA TODAY BUT STILL REMAIN VFR INTO EARLY THIS EVENING. AFTER THAT...PERSISTENT MOISTURE ADVECTION FROM THE SOUTH WILL BRING ABOUT SOME MVFR CIGS LATE THIS EVENING AND OVERNIGHT. THE BETTER CHANCES FOR -RA WILL BE OVER PIA AND SPI TODAY BUT STILL WILL CARRY VCSH OVER AT BMI AND DEC. TONIGHT...AS THE BOUNDARY APPROACHES FROM THE SOUTH...WILL INCLUDE VCTS IN THE FORECAST GROUPS AS WE SEE SOME ELEVATED INSTABILITY DRAWN NORTHWARD. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 10 TO 15 KTS WITH OCCASIONAL GUSTS TO AROUND 20 KTS. LOOK FOR WINDS TO VEER MORE INTO THE SOUTH TONIGHT WITH SPEEDS ONCE AGAIN IN THE 10 TO 15 KT RANGE. WILL NEED TO WATCH FOR THE POTENTIAL FOR NON- CONVECTIVE LOW LEVEL WIND SHEAR OVERNIGHT AS SOUNDINGS INDICATE 40-50 KTS AT 1500-2500 FEET AFTER 03Z. FOR NOW...WITH THE THREAT FOR SCATTERED TSRA IN THE AREA...WILL HOLD OFF MENTIONING IN THIS SET OF FORECASTS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...BARNES LONG TERM...BARNES AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
603 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY) ISSUED AT 319 AM CDT THU MAY 14 2015 1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE. .LONG TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 319 AM CDT THU MAY 14 2015 UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A CHANCE OF THUNDER ACROSS THE BOARD TONIGHT. ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE 60S. WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE MAY NEED TO BE REMOVED BY LATER SHIFTS. ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS DIPPING INTO THE 40S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 600 AM CDT THU MAY 14 2015 VFR CONDITIONS ARE EXPECTED THRU THE DAY WITH POSSIBLE MVFR CIGS AFTR 04Z TONIGHT AS A WARM FRONT LIFTS TOWARDS THE AREA. A LARGE AREA OF LIGHT RAIN WAS MAKING SLOW PROGRESS TO THE EAST AS IT ENCOUNTERS SOME VERY DRY AIR AT THE LOW LEVELS OF THE ATMOSPHERE. LATEST RAP FORECAST SOUNDINGS INDICATING CIGS WILL GRADUALLY LOWER AS THE MOISTURE WORKS ITS WAY INTO OUR AREA TODAY BUT STILL REMAIN VFR INTO EARLY THIS EVENING. AFTER THAT...PERSISTENT MOISTURE ADVECTION FROM THE SOUTH WILL BRING ABOUT SOME MVFR CIGS LATE THIS EVENING AND OVERNIGHT. THE BETTER CHANCES FOR -RA WILL BE OVER PIA AND SPI TODAY BUT STILL WILL CARRY VCSH OVER AT BMI AND DEC. TONIGHT...AS THE BOUNDARY APPROACHES FROM THE SOUTH...WILL INCLUDE VCTS IN THE FORECAST GROUPS AS WE SEE SOME ELEVATED INSTABILITY DRAWN NORTHWARD. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 10 TO 15 KTS WITH OCCASIONAL GUSTS TO AROUND 20 KTS. LOOK FOR WINDS TO VEER MORE INTO THE SOUTH TONIGHT WITH SPEEDS ONCE AGAIN IN THE 10 TO 15 KT RANGE. WILL NEED TO WATCH FOR THE POTENTIAL FOR NON- CONVECTIVE LOW LEVEL WIND SHEAR OVERNIGHT AS SOUNDINGS INDICATE 40-50 KTS AT 1500-2500 FEET AFTR 03Z. FOR NOW...WITH THE THREAT FOR SCATTERED TSRA IN THE AREA...WILL HOLD OFF MENTIONING IN THIS SET OF FORECASTS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...BARNES AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1021 AM EDT THU MAY 14 2015 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EDT THU MAY 14 2015 WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL... STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 1013 AM EDT THU MAY 14 2015 ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION FOLLOWS... ISSUED AT 329 AM EDT THU MAY 14 2015 HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE MID 40S TO THE MID 50S. THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO VALLEY AHEAD OF IT. EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL CONTINUE WITH A DRY FORECAST TODAY. TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS GUIDANCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 329 AM EDT THU MAY 14 2015 FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE PERIOD. UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED. SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40 POPS OVER THE ENTIRE FORECAST AREA. REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT. TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK. WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY FORECAST AFTER MONDAY. && .AVIATION /DISCUSSION FOR THE 141200Z TAFS/... ISSUED AT 630 AM EDT THU MAY 14 2015 LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE TERMINALS TODAY. SURFACE WINDS 110-140 DEGREES AT 8-12 KTS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...RYAN NEAR TERM...MRD/RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1020 AM EDT THU MAY 14 2015 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EDT THU MAY 14 2015 WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL... STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE MID 40S TO THE MID 50S. THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO VALLEY AHEAD OF IT. EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL CONTINUE WITH A DRY FORECAST TODAY. TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS GUIDANCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 329 AM EDT THU MAY 14 2015 FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE PERIOD. UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED. SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40 POPS OVER THE ENTIRE FORECAST AREA. REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT. TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK. WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY FORECAST AFTER MONDAY. && .AVIATION /DISCUSSION FOR THE 141500Z IND TAF UPDATE/... ISSUED AT 1020 AM EDT THU MAY 14 2015 NOTHING TO NOTE REGARDING UPDATE. PREVIOUS DISCUSSION FOLLOWS... ISSUED AT 630 AM EDT THU MAY 14 2015 LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE TERMINALS TODAY. SURFACE WINDS 110-140 DEGREES AT 8-12 KTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...JAS/MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
630 AM EDT THU MAY 14 2015 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EDT THU MAY 14 2015 WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL... STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE MID 40S TO THE MID 50S. THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO VALLEY AHEAD OF IT. EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL CONTINUE WITH A DRY FORECAST TODAY. TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS GUIDANCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 329 AM EDT THU MAY 14 2015 FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE PERIOD. UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED. SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40 POPS OVER THE ENTIRE FORECAST AREA. REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT. TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK. WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY FORECAST AFTER MONDAY. && .AVIATION /DISCUSSION FOR THE 141200Z TAFS/... ISSUED AT 630 AM EDT THU MAY 14 2015 LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE TERMINALS TODAY. SURFACE WINDS 110-140 DEGREES AT 8-12 KTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
626 AM CDT THU MAY 14 2015 .SYNOPSIS... ISSUED AT 312 AM CDT THU MAY 14 2015 AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN 2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION SHOULD CONTINUE TO BE SEEN. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CDT THU MAY 14 2015 TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z. HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10 PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY. TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT. MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700 PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH. ERVIN .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 312 AM CDT THU MAY 14 2015 FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S. THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500 J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD. CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST. THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN. HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK 850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI. SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER THAN FRIDAY AS WELL. SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE ISOLATED. FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION VECTORS AND PWAT VALUES NEAR 1.50 INCHES. SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE SFC COLD FRONT. MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 615 AM CDT THU MAY 14 2015 A SLOW MOVING BAND OF RAIN WILL MOVE EAST AFFECTING EASTERN IOWA TERMINALS THROUGH LATE MORNING. CLOUD BASES WILL BE QUITE HIGH...WITH CIGS AROUND 12000 FT...LOWERING BY AFTERNOON TO AROUND 5000 FT. A WARM FRONT WILL BRING MORE MOIST AIR TO THE REGION BY TONIGHT...RESULTING IN CIGS LOWERING TO AROUND 2000 TO 3000 FT...AND VISIBILITIES TO 3 TO 5 MILES IN LIGHT FOG...AND SOME SHOWERS. CONDITIONS ARE LIKELY TO REMAIN SOMEWHAT VARIABLE AFTER 00Z...WITH PASSING SHOWERS AND EVEN A THUNDERSTORM POSSIBLE. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...ERVIN SHORT TERM...ERVIN LONG TERM...UTTECH AVIATION...ERVIN
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
930 AM MDT THU MAY 14 2015 .UPDATE... MADE A FEW CHANGES TO THE FORECAST THROUGH THIS EVENING. STRATUS HAD OVERSPREAD THE AREA WITH THE EXCEPTION OF THE MOUNTAINS AND NEARBY FOOTHILLS. MID CLOUDS WERE MOVING N OVER THE WESTERN ZONES IN THE MOIST FLOW AHEAD OF THE UPPER LOW ALONG THE W COAST. IN GENERAL...HAVE INCREASED CLOUD COVER OVER MOST OF THE AREA THROUGH THE DAY. RAP SOUNDINGS DID SHOW CLOUDS IN THE E DISSIPATING THIS AFTERNOON SO REFLECTED THIS IN THE GRIDS. ALSO WEBCAMS/SURFACE OBSERVATIONS INDICATED PATCHY FOG OVER MOST OF THE AREA...SO HAVE SPREAD THE FOG MENTION FURTHER W THROUGH 18Z. DUE TO THE CLOUD COVER...HAVE LOWERED TEMPERATURES A COUPLE OF DEGREES TOWARD THE NEW WRF. THE CLOUDS WILL INHIBIT THUNDERSTORM FORMATION...SO HAVE CONFINED THUNDER TO THE SUNNIER AREAS...IE...THE MOUNTAINS AND FOOTHILLS THIS AFTERNOON AND EVENING. SREF SHOWED GOOD PROBABILITIES OF 500 J/KG OF SURFACE CAPE IN THESE AREAS...WITH CAPES DIMINISHING QUICKLY THIS EVENING. RAP SHOWED MARGINAL SHEAR OVER THE AREA. NEW WRF SHOWED DRY SLOT MOVING N QUICKLY LATE TONIGHT WHICH WOULD CONTRADICT THE HIGH POPS AFTER 06Z. WILL WAIT TIL MORE GUIDANCE COMES IN BEFORE MAKING ANY CHANGES LATE TONIGHT. ARTHUR && .SHORT TERM...VALID FOR TDY AND FRI... MINIMAL CHANGES TO THE SHORT TERM FORECAST PERIOD...AS UNSETTLED PATTERN PERSISTS. MODELS HAVE BEEN CONSISTENT WITH THIS PATTERN FOR SEVERAL DAYS...SO FORECAST IS IN GOOD SHAPE OVERALL. DIFFLUENT FLOW ALOFT AHEAD OF APPROACHING UPPER LEVEL PACIFIC LOW PRESSURE SYSTEM...AND PERSISTENT UPSLOPE SFC FLOW PREVAIL ACROSS THE REGION FOR TODAY AND FRIDAY. INCREASING MOISTURE AVAILABILITY AND SHORTWAVE ACTIVITY ARE ALSO EXPECTED THROUGH THE PERIOD...RESULTING IN INCREASING CHANCES FOR PRECIPITATION. ADDITIONALLY...IMPROVED CAPES AND SHEAR PROFILE THROUGH THE TODAY...WILL LEND SUPPORT FOR INCREASED CHANCES OF THUNDER TODAY AND INTO TONIGHT. BEST CHANCES TODAY WILL BE FROM SHERIDAN TO BILLINGS AND WEST THROUGH THIS AFTERNOON...AND SPREADING EASTWARD THROUGH THIS EVENING AND TONIGHT. SHOWERS WILL BE MORE WIDESPREAD ON FRIDAY. SHEAR AND CAPE DO NOT APPEAR QUITE AS GOOD FOR FRIDAY...AND WILL ALSO HAVE LIMITED POTENTIAL FOR ADDITIONAL ENERGY FROM DIURNAL HEATING WITH CLOUD COVER. SO THUNDER POTENTIAL APPEARS A BIT LOWER FOR FRIDAY...BUT HAVE STILL KEPT A MENTION OF THUNDER AT THIS TIME. TEMPS WILL STILL HAVE A CHANCE TO WARM UP...BUT COOLING TREND WILL BEGIN TODAY. HIGHS IN THE UPPER 50S TO UPPER 60S ARE EXPECTED. CLOUD COVER ACROSS THE REGION...AND PERSIST SHOWER ACTIVITY ON FRIDAY WILL LIMIT TEMPS TO MAINLY THE 50S. SOME AREAS ALONG THE SOUTHERN BORDER MAY CREEP INTO THE 60S...BUT WILL GREATLY DEPEND ON HOW FAR NORTH DRY SLOTTING OCCURS. AAG .LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED... WET WEATHER COMING THIS WEEKEND THOUGH THERE ARE STILL SOME DETAILS TO BE WORKED OUT. ENERGY EMERGING FROM DEEP WESTERN CONUS LOW WILL LIFT OUT OF WY FRIDAY NIGHT AND CLOSE OFF SOMEWHERE OVER SOUTHEAST MT ON SATURDAY. GOOD GENERAL CONSENSUS AMONG THE MODELS HERE BUT THE EXACT LOCATION OF THE MID LEVEL LOW WILL BE CRUCIAL. WILL CONTINUE TO FOLLOW A MODEL BLEND IN THIS REGARD. BEST CHANCE OF RAIN SATURDAY WILL BE FROM BILLINGS WEST AND NORTHWARD...WITH DRY SLOTTING A REAL POSSIBILITY IN FAR SOUTHEAST MT AND SHERIDAN COUNTY. BILLINGS MAY NOT FAR FROM THE EDGE BUT ALL MODELS TAKE MID LEVEL LOW TO OUR EAST WHICH WOULD SUGGEST PLENTY OF RAIN FOR THE METRO AREA ON SATURDAY. IF THE LOW WERE TO TRACK JUST SLIGHTLY WEST WE COULD SEE A BREAK IN THE PCPN. OVER TIME AS THE LOW SHIFTS EAST WE WILL SEE TROWAL WRAP BACK THROUGH OUR AREA AS THE FLOW TURNS NORTHERLY. THIS WILL RESULT IN WIDESPREAD PCPN SATURDAY NIGHT INTO SUNDAY. LOW WILL DEPART SUNDAY AFTERNOON AND NIGHT WITH DRIER AIR ADVECTING IN FROM THE NORTH. AS FOR PCPN AMOUNTS...GFS SEEMS TO BE SUFFERING SOME CONVECTIVE FEEDBACK ISSUES BUT A MODEL BLEND WILL STILL PRODUCE A WIDESPREAD 1-2 INCHES WITH LOCALLY HIGHER AMTS...IE MAYBE 3 INCHES...AIDED BY CONVECTIVE ENHANCEMENT PRIOR TO THE SATURDAY TROWAL. SHOULD ALSO BE NOTED THAT GULF MOISTURE WILL BE INVOLVED SO MOISTURE AVAILABILITY WILL NOT BE AN ISSUE THROUGH THE COURSE OF THIS EVENT. MOUNTAINS COULD SEE SIGNIFICANT SNOWFALL ESPECIALLY BEGINNING SATURDAY NIGHT AS WE COLD ADVECT AND 700MB TEMPS FALL TO NEAR -5C. WILL ALSO NEED TO KEEP AN EYE ON CLIPPER WHICH WILL EMERGE FROM THE CANADIAN ARCTIC AND PUSH THROUGH SASKATCHEWAN BY SATURDAY NIGHT. THIS WILL BE ASSOCIATED WITH A LOW LEVEL COLD SURGE WHICH COULD DROP 850MB TEMPS TO NEAR 0C BY SUNDAY. IT IS NOT OUT OF THE QUESTION THAT SOME OF THE HIGHER HILLS OF SOUTHEAST MT COULD SEE A MIX WITH WET SNOW ON SUNDAY PRIOR TO THE DRYING. SHORTWAVE RIDGE WILL BUILD IN SUNDAY NIGHT AND MONDAY FOR A BRIEF PERIOD OF QUIETER WEATHER. NEXT PACIFIC TROF WILL MOVE INTO THE WESTERN CONUS AND SET THE STAGE FOR ANOTHER PERIOD OF UPPER DIFFLUENT FLOW...GULF MOISTURE ADVECTION AND A GOOD CHANCE OF SHOWERS IN OUR REGION FROM MONDAY NIGHT THROUGH WEDNESDAY. ANOTHER WIDESPREAD PCPN EVENT IS A POSSIBILITY AS SUGGESTED BY THE MOST RECENT GFS. TEMPERATURES WILL BE WELL BELOW NORMAL THIS WEEKEND WITH MOST AREAS SEEING HIGHS ONLY IN THE 50S. SHOULD SEE SOME MODEST MODERATION NEXT MONDAY/TUESDAY BUT WITH A PERSISTENT EAST WIND REGIME KEEPING OUR TEMPS IN CHECK. TEMPS SHOULD STAY BELOW NORMAL THROUGH THE MIDDLE OF NEXT WEEK. JKL && .AVIATION... AREA OF STRATUS WITH MVFR TO LOCAL IFR CEILINGS WILL IMPACT OUR ENTIRE AREA THIS MORNING...THE EXCEPTION BEING KLVM...KSHR AND THE FOOTHILLS LOCATIONS WHERE VFR CONDITIONS WILL PREVAIL. CONDITIONS ARE EXPECTED TO IMPROVE TO VFR BY 18Z. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG AND WEST OF A KSHR- KBIL LINE THIS AFTERNOON AND EVENING. MVFR CONDITIONS WILL BE POSSIBLE IN ANY SHOWER/THUNDERSTORM ACTIVITY. THE MOUNTAINS WILL BE OBSCURED AT TIMES. HOOLEY && .PRELIMINARY POINT TEMP/POPS... TDY FRI SAT SUN MON TUE WED ------------------------------------------------------- BIL 064 048/056 045/053 041/052 038/060 041/056 042/055 2/W 66/T 78/W 76/W 22/W 24/W 55/W LVM 058 044/056 040/053 038/054 035/058 037/055 038/057 4/T 56/T 78/W 75/W 23/T 35/W 54/W HDN 068 047/060 045/055 041/052 035/063 041/059 041/057 1/E 56/T 67/W 76/W 22/W 24/W 55/W MLS 065 046/058 046/058 041/052 035/058 040/058 041/058 1/B 36/T 87/T 77/W 21/B 23/W 44/W 4BQ 066 047/058 046/062 042/049 032/059 039/055 039/055 1/B 46/T 75/T 77/W 21/B 34/W 55/W BHK 061 042/058 045/063 041/049 031/055 036/055 038/055 1/B 16/T 85/T 66/W 21/B 23/W 44/W SHR 064 044/061 041/056 038/050 034/058 040/055 038/055 2/T 66/T 56/W 77/W 22/T 35/W 55/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
621 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 326 AM CDT THU MAY 14 2015 TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR HIGHS IN THE 70S TO 80 SOUTH. WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING SCATTERED TSTMS FROM 06Z ONWARD. INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 326 AM CDT THU MAY 14 2015 LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE. DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS. LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION. THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE. MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK NORTH AND EAST THROUGH THE EVENING. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7 RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR WIDESPREAD QPF AND STRONG MODEL CONSENSUS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 620 AM CDT THU MAY 14 2015 IMPROVEMENT TO VFR IS EXPECTED 15Z-18Z THIS MORNING...LARGELY THE RESULT OF MIXING PROCESSES. OTHERWISE...SATELLITE TIMING TOOLS SUGGEST MVFR WOULD LAST ALL DAY EAST OF HIGHWAY 61. TONIGHT...AN UPPER LEVEL DISTURBANCE ACROSS AZ SHOULD MOVE THROUGH THE FCST AREA. THE MODELS SUGGEST SCATTERED TSTMS WILL DEVELOP AS THE DISTURBANCE MOVES THROUGH THE FCST AREA. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MARTIN AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
607 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT THU MAY 14 2015 ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3) TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK). STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM) WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID 0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS. LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN MOST PLACES. NOW LOOKING AHEAD FORECAST-WISE... EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO- NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST. HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE POP IS BELOW 20 PERCENT. WOULD NORMALLY BE A BIT MORE CONCERNED ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING. TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY. THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13 NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST BREEZES THIS MORNING WILL STEADILY BECOME MORE SOUTHWESTERLY IF NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT EXPECTED TO AVERAGE MORE THAN 10-15 MPH. THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN 1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE- MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST. COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500 J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61 DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY 1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE FOCUS REMAIN ON THE THUNDERSTORM CHANCES. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 420 AM CDT THU MAY 14 2015 A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS. OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK. STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR 60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO. AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY... EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER. CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID WEEK TO BE MORE ISOLATED ACROSS THE REGION. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 606 AM CDT THU MAY 14 2015 ALTHOUGH CONFIDENCE REMAINS FAIRLY HIGH THAT A MULTI-HOUR PERIOD OF VFR CEILING/VISIBILITY WILL MATERIALIZE BEYOND THE FIRST 6-8 HOURS OF THE PERIOD (POTENTIALLY LASTING WELL INTO THE NIGHT)...MVFR/IFR CEILING AND VISIBILITY WILL CONTINUE TO BE THE MAIN ISSUE THIS MORNING INTO EARLY THIS AFTERNOON...ALONG WITH A FEW HOURS OF LIGHT DRIZZLE POTENTIAL. OBVIOUSLY TIMING IN THE SPECIFICS OF THE RETURN TO VFR CONDITIONS IS SOMEWHAT UNCERTAIN...BUT WILL CONTINUE TO AIM FOR VFR VISIBILITY BY LATE MORNING AND VFR CEILING BY AROUND 20Z THIS AFTERNOON. DURING THE LATTER HALF OF THE PERIOD...HAVE BROUGHT IN A VICINITY THUNDERSTORM (VCTS) MENTION FOR LATE TONIGHT...WITH SOME SMALL HAIL POSSIBLE SHOULD ANY OF THESE STORMS DIRECTLY AFFECT THE TERMINALS. CANNOT RULE OUT SOME SUB-VFR CEILING/VISIBILITY AGAIN TONIGHT AS WELL...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO GO THERE YET. WIND-WISE...FAIRLY LIGHT BREEZES ONLY AROUND 10KT OR LESS SHOULD PREVAIL THROUGH THE PERIOD...WITH DIRECTION TRANSITIONING FROM SOUTH RIGHT AWAY THIS MORNING...TO SOUTHWEST MOST OF THE DAY...AND THEN SOUTHEAST THIS EVENING/TONIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...ROSSI AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
809 AM PDT THU MAY 14 2015 .SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES. && .UPDATE...A QUICK UPDATE TO ADD SHOWERS/STORMS TO PORTIONS OF CLARK COUNTY INCLUDING THE LV VALLEY UP THROUGH LINCOLN COUNTY BASED ON LATEST RADAR TRENDS AND LIGHTNING DATA. -SALMEN-&& .PREVIOUS DISCUSSION...256 AM PDT... .SHORT TERM...THROUGH SATURDAY NIGHT. THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS THE MOJAVE DESERT. WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON. WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE... BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH. WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST ANY WIND HEADLINES. BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH. FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL AVERAGES. ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY BUT STILL BE AROUND 15 DEGREES BELOW NORMAL. .LONG TERM...SUNDAY THROUGH THURSDAY. SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON. THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND. && .AVIATION... FOR MCCARRAN...INCREASING CLOUDS AND LOWERING CEILINGS EXPECTED TODAY AS A PACIFIC STORM IMPACTS THE REGION. SOUTH WINDS OF 15-25KT EXPECTED WITH GUSTS TO 30KTS BUT SOME VARIABILITY POSSIBLE WHILE SHOWERS MOVE THROUGH THE VALLEY IN THE LATE AFTERNOON. CIGS FALLING IN THE 8-10K FT RANGE THIS AFTERNOON AND EVENING. ADDITIONAL RAIN AND REDUCED CIGS POSSIBLE FRIDAY. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE. BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED. && .SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ SHORT TERM/AVIATION...OUTLER LONG TERM...ADAIR FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
605 AM MDT THU MAY 14 2015 .AVIATION... 12Z TAF CYCLE VFR CONDITIONS TO CONTINUE TO BE THE RULE THROUGH THE 12Z FRI... BUT THERE WILL BE A FEW EXCEPTIONS. ONE WILL BE ACROSS FAR EAST CENTRAL NM NEAR THE TX STATE LINE WHERE IFR AND POSS LIFR CIGS WILL BE A POSSIBILITY TIL ABOUT 16Z TODAY AND THEN AFTER ROUGHLY 09Z FRI ACROSS AREAS MAINLY SOUTH OF INTERSTATE 40 AND FROM THE PECOS RIVER VALLEY ON EAST. OTHERWISE...S TO SW LOW LEVEL FLOW TO INCREASE LATE THIS MORN AND AFTN. HIGHEST TERMINAL FCST GUSTS LIKELY TO BE AT KLVS THIS AFTN...IN THE VCNTY OF 34 TO 36KTS. A FEW HIGH BASED AND GUSTY -SHRA AND -TSRA ACROSS NORTH AND FAR WEST NM MAY IMPACT KFMN AND KGUP BETWEEN ABOUT 20Z AND 02Z. A LOWER CHANCE FOR ISOLD TSRA ARE POSSIBLE LATE TODAY AS WELL...MAINLY NEAR THE TX LINE...POSS IMPACTING KTCC. 43 && .PREV DISCUSSION...330 AM MDT THU MAY 14 2015... .SYNOPSIS... ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE. SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY. && .DISCUSSION... WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT. SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7 WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY. && .FIRE WEATHER... A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY... PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA. STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH. BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS... MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED. ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD. 43 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1028 AM CDT THU MAY 14 2015 .UPDATE... ISSUED AT 1029 AM CDT THU MAY 14 2015 SURFACE LOW PRESSURE CENTERED OVER WESTERN NEBRASKA WITH A QUASI- STATIONARY SURFACE FRONT EXTENDING FROM THE LOW NORTH-NORTHEAST ACROSS THE CENTRAL DAKOTAS INTO NORTHEASTERN NORTH DAKOTA. STRONG MID LEVEL S/WV TROUGH LIFTING ACROSS THE EASTERN DAKOTAS TOWARDS THE UPPER MISSISSIPPI VALLEY REGION. SHOWERS...SOME AREAS MODERATE...CONTINUE ALONG THE FRONTAL ZONE ACROSS SOUTH CENTRAL NORTH DAKOTA INTO NORTHEASTERN NORTH DAKOTA THIS MORNING. RAINFALL AMOUNTS WITHIN THE BAND HAVE GENERALLY BEEN IN THE RANGE OF 0.5-0.75"...WITH AMOUNTS IN EARLIER CONVECTIVE BANDS IN EXCESS OF AN INCH. SHOWERS WILL CONTINUE TO SLOWLY LIFT NORTH AND EAST AS THE DAY PROGRESSES...AND SHOULD BE ENTIRELY OUT OF MY EASTERN COUNTIES BY 03Z. OTHER UPDATE WITH THIS FORECAST PACKAGE WAS TO LOWER TEMPERATURES CENTRAL AS LOW CLOUD COVER IS NOW FORECAST TO PERSIST THROUGH THE AFTERNOON AS PER THE LAST FEW HIGH RES HRRR MODEL RUNS ALONG WITH THE LATEST NAM/RAP LOW LEVEL RH FORECAST. STILL EXPECT CLEARING WEST...THOUGH STRATUS FIELD IS EXTENSIVE. HIGH RES MODELS INDICATE OVC CIGS TRENDING FEW-SCT 16-19Z ACROSS MY WEST...SO WILL MONITOR IN CASE CLOUD COVER NEEDS TO BE INCREASED AND TEMPS DROPPED. UPDATE ISSUED AT 640 AM CDT THU MAY 14 2015 SHOWERS CONTINUE TO LIFT SLOWLY NORTHWARD ACROSS CENTRAL AND EASTERN NORTH DAKOTA. LATEST BOWMAN RADAR SHOWS RETURNS DRYING UP OVER WESTERN NORTH DAKOTA...THUS CURRENT RADAR TRENDS LOOK GOOD. OTHERWISE NO SIGNIFICANT UPDATES TO THE CURRENT FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 346 AM CDT THU MAY 14 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE WIDESPREAD SHOWERS TODAY WITH SOME AREAS CENTRAL SEEING HEAVY RAINFALL. CURRENTLY...AN UPPER LEVEL LOW/SHORTWAVE LIFTING NORTHEAST THROUGH THE CENTRAL AND NORTHERN PLAINS WAS ASSOCIATED WITH WIDESPREAD SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ACROSS THE STATE. LIGHTNING ACTIVITY HAD DECREASED IN THE LAST HOUR...AND MESOANALYSIS INDICATES THAT CAPE HAS DECREASED ACROSS THE REGION. AT THE SURFACE...LOW PRESSURE WAS OVER WYOMING WITH A WARM FRONT EXTENDING FROM THE LOW NORTHEASTWARD TO NEAR FORT YATES TO NEAR DEVILS LAKE TO THE NORTHEAST CORNER OF NORTH DAKOTA. FORECAST CAPE VALUES FOR TODAY ARE LOW ENOUGH TO KEEP THE MENTION OF THUNDER OUT OF THE FORECAST FOR THE DAYTIME PERIOD. PRECIPITABLE WATER FORECASTS OF 1.00" TO 1.20" FOR SOUTH CENTRAL NORTH DAKOTA...ALONG THE SURFACE WARM FRONT. WIDESPREAD AREAS OF 0.50" OF RAIN ARE POSSIBLE TODAY ALONG AND EAST OF A LINE FROM THE TURTLE MOUNTAINS TO BISMARCK/MANDAN TO GRANT COUNTY. LOCALLY HIGHER AMOUNTS ARE POSSIBLE. THE UPPER LEVEL SHORTWAVE AND SURFACE WARM FRONT ARE PROGGED TO MOVE EAST TODAY. EXPECT SHOWERS TO DECREASE FROM WEST TO EAST TODAY...LINGERING IN CENTRAL NORTH DAKOTA THIS AFTERNOON BEFORE TAPERING OFF DURING THE EVENING HOURS. AS THE SURFACE WARM FRONT MOVES EAST...HIGH PRESSURE IN SOUTH CENTRAL CANADA WILL PUSH SOUTHWARD INTO THE STATE. HIGHS TODAY SHOULD RANGE IN THE 50S TO LOWER 60S...WITH LOWS TONIGHT FROM THE UPPER 30S TO MID 40S. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 346 AM CDT THU MAY 14 2015 STRONG VERTICALLY STACKED SYSTEM WILL INFLUENCE THE WEATHER ACROSS THE NORTHERN PLAINS FRIDAY THROUGH SUNDAY. MAIN FORECAST ISSUES IN THE LONG TERM ARE SEVERE POTENTIAL ON SATURDAY...PRECIPITATION AMOUNTS AND POSSIBLE LOCALIZED FLOODING ISSUES THROUGH THE WEEKEND AND THE POTENTIAL FOR FREEZING TEMPERATURES MONDAY TUESDAY MORNINGS ON THE BACK SIDE OF THIS SYSTEM. WE START OFF ON A QUIET NOTE FRIDAY AS THE UPPER LEVEL SYSTEM TRACKS ACROSS THE INTER-MOUNTAIN WEST AND BEGINS TO TAKE SHAPE OVER THE NORTHERN HIGH PLAINS. WE BEGIN THE DAY DRY WITH SURFACE HIGH PRESSURE OVER THE FORECAST AREA. SOUTHEAST FLOW ALOFT WILL INCREASE OVER WESTERN NORTH DAKOTA AS CYCLOGENESIS TAKES PLACE OVER THE NORTHERN AND CENTRAL HIGH PLAINS. PRECIPITATION IS EXPECTED TO DEVELOP BY AFTERNOON OVER THE SOUTHWEST AND BEGIN TO SPREAD NORTH AND EAST. FRIDAY NIGHT THROUGH SATURDAY MORNING...STRONG WARM ADVECTION ENVELOPES WESTERN AND CENTRAL NORTH DAKOTA WITH A SURFACE AND UPPER LOW DEVELOPING OVER NORTHEAST MONTANA. MODELS ARE PRETTY SIMILAR IN BRINGING A BAND OF PRECIPITATION SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY MORNING...WITH THE MAJORITY OF THE PRECIPITATION OVER THE NORTHERN TIER COUNTIES ALONG THE DEFORMATION ZONE BY MIDDAY SATURDAY. INSTABILITY ALOFT IS LIMITED INITIALLY BUT IS EXPECTED TO INCREASE DURING THE NIGHT ACROSS NORTHERN SOUTH DAKOTA INTO SOUTHERN NORTH DAKOTA. MOST UNSTABLE CAPES OF 500-1000 J/KG WITH 20-40KTS OF 0-6KM SHEAR LAY ACROSS THE NORTHERN SOUTH DAKOTA BORDER LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING. THUS A THREAT OF SEVERE WEATHER CAN NOT BE RULED OUT DURING THIS PERIOD...BUT EXPECT THE BETTER THREAT WILL REMAIN SOUTH OF THE BORDER. SATURDAY AFTERNOON...POSSIBLY AS EARLY AS LATE SATURDAY MORNING THE FIRST WAVE OF PRECIPITATION WILL HAVE MOVED THROUGH AND MODELS SUGGEST A DRY SLOT WORKING INTO CENTRAL NORTH DAKOTA AS AN 80 KT UPPER LEVEL JET PUSHES INTO EASTERN NORTH DAKOTA BY AROUND MIDDAY SATURDAY. THIS SHOULD ALLOW FOR A DESTABILIZING ATMOSPHERE DURING THE LATE MORNING AND AFTERNOON AS SURFACE TEMPERATURES RISE INTO THE 70S ACROSS THE SOUTHERN HALF OF THE STATE. A STRONG SOUTHERN STREAM JET OVER THE SOUTHWEST U.S. BEGINS LIFTING INTO THE SOUTHERN AND CENTRAL PLAINS...ALLOWING THE NORTHERN STACKED SYSTEM OVER EASTERN MONTANA TO BEGIN MOVING EAST. ALTHOUGH DIRECTIONAL SHEAR IS NOT IMPRESSIVE...SUFFICIENT BULK SHEAR AND CAPE WILL BE AVAILABLE DURING THE LATE MORNING THROUGH THE AFTERNOON THAT SEVERE STORMS ARE POSSIBLE. WILL STILL NEED TO MONITOR TRENDS OF THE NEXT DAY OR SO TO HOPEFULLY GET A BETTER IDEA. SATURDAY NIGHT THROUGH SUNDAY...ANY SEVERE WEATHER THREAT SATURDAY SHOULD QUICKLY DIMINISH FROM WEST TO EAST SATURDAY NIGHT INTO SUNDAY MORNING AS THE SURFACE LOW CONTINUES TO TRACK EAST ACROSS THE DAKOTAS. STRONG NORTHERLY FLOW WILL BRING MUCH COOLER TEMPERATURES FROM WEST TO EAST SUNDAY...WITH MAINLY IN THE 40S NORTH AND WEST...TO THE LOWER 60S SOUTHEAST. THE STRONG SOUTHERN SHORTWAVE LIFTING THROUGH THE SOUTHERN AND CENTRAL PLAINS SATURDAY MOVES INTO THE NORTHERN PLAINS SUNDAY AND MERGES WITH THE STACKED SYSTEM TRACKING ACROSS THE DAKOTAS. BY SUNDAY AFTERNOON THE THREAT OF SEVERE WEATHER WILL BE TO THE EAST OF THE DAKOTAS...BUT A BAND OF PRECIPITATION IN THE DEFORMATION ZONE IS EXPECTED OVER EASTERN AND POSSIBLY BACK INTO CENTRAL NORTH DAKOTA. THUS SOME PRETTY HEFTY PRECIPITATION AMOUNTS COULD FALL OVER SOUTH CENTRAL INTO NORTHEAST NORTH DAKOTA. WILL NEED TO MONITOR FOR SOME AREAS RECEIVING ENOUGH RAIN TO PRODUCE LOCAL FLOODING ISSUES. ESPECIALLY IF THEY GET HIT WITH PRECIPITATION A FEW TIMES BEFORE THIS. PRECIPITATION FINALLY MOVES OUT OF THE AREA BY SUNDAY EVENING WITH COLD HIGH PRESSURE BUILDING OVER THE AREA INTO EARLY NEXT WEEK. WITH THE SURFACE HIGH MOVING INTO NORTH DAKOTA BY MONDAY MORNING IT LOOKS LIKE A GOOD BET THAT WE WILL NEED A FROST ADVISORY OR MORE LIKELY A FREEZE WARNING...IF CURRENT TEMPERATURE TRENDS HOLD. WE COULD STILL BE DEALING WITH FROST ON TUESDAY MORNING AS WELL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 640 AM CDT THU MAY 14 2015 WIDESPREAD MVFR WITH LCL IFR CONDITIONS WILL CONTINUE TO SPREAD OVER THE AREA WITH SHRA SPREADING NORTHWARD. CONDITIONS WILL IMPROVE TO VFR OVER PORTIONS OF NORTHWEST NORTH DAKOTA THURSDAY AFTERNOON...WHILE MOST AREAS WILL REMAIN IFR-MVFR. KISN SHOULD SEE A RETURN OF MVFR-IFR AFT 02Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...JV LONG TERM...TWH AVIATION...JV
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AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 307 AM CDT THU MAY 14 2015 WATER VAPOR IMAGERY THIS MORNING SHOWS A VIGOROUS MID-LEVEL TROUGH LIFTING NORTHEAST ACROSS THE PLAINS WHILE A RIDGE OF HIGH PRESSURE EXTENDED N/S ACROSS OUR AREA. FORCING FROM THIS TROUGH WAS PRODUCING A WIDESPREAD SWATH OF SHOWERS ACROSS EASTERN NEB/WESTERN IA... PUSHING NORTHEAST TOWARD THE AREA. OTHERWISE...PLENTY OF HIGH/MID CLOUD ACROSS THE FORECAST AREA WITH TEMPERATURES AT 2 AM RANGING FROM THE LOWER/MID 40S ACROSS NORTHERN AND CENTRAL WI...TO THE MIDDLE 50S ALONG AND WEST OF THE MISSISSIPPI RIVER. LOOK FOR THAT MID-LEVEL TROUGH TO CONTINUE LIFTING NORTHEAST INTO CENTRAL MN/IA BY LATE THIS AFTERNOON. GOOD AMOUNT OF 850-300MB PV- ADVECTION AND 850MB MOISTURE TRANSPORT WILL CONTINUE TO FUEL SHOWERS AS THEY SLOWLY PUSH INTO THE AREA FROM WEST TO EAST. DRIER LOWER LEVELS ASSOCIATED WITH DEPARTING SURFACE HIGH PRESSURE WILL LIKELY HOLD BULK OF THE SHOWERS WEST OF THE MISSISSIPPI RIVER THROUGH NOON...BEFORE THEY OVERSPREAD THE REST OF THE AREA THROUGH THE AFTERNOON HOURS. DUE TO THE CLOUDS AND INCOMING SHOWERS... TEMPERATURES WILL SUFFER SOMEWHAT...RANGING FROM THE UPPER 50S TO THE LOWER 60S. SHOWERS WILL CONTINUE THROUGH MIDNIGHT ACROSS MOST OF THE AREA...THEN START A SLOW DIMINISHING TREND FROM WEST TO EAST AFTER MIDNIGHT AS THE TROUGH DEPARTS EAST AND RIDGING BUILDS IN FROM MN/IA. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE UPPER 40S TO THE MIDDLE 50S. APPEARS RAINFALL FROM THIS SYSTEM WILL BE SOMEWHERE IN THE 1/2 TO 3/4 INCH RANGE. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 307 AM CDT THU MAY 14 2015 A FEW VERY LIGHT SHOWERS MAY BE ONGOING EARLY FRIDAY MORNING EAST OF THE MISSISSIPPI RIVER EARLY IN THE MORNING AS THE TROUGH DEPART... BUT SKIES ARE EXPECTED TO BECOME PARTLY CLOUDY BY AFTERNOON AS A RIDGE OF HIGH PRESSURE WORKS INTO THE AREA. PLAN ON HIGHS IN THE UPPER 60S THE THE LOWER 70S. FOCUS THEN SHIFTS TO THE POTENTIAL FOR SOME STRONG TO SEVERE STORMS THROUGH THE WEEKEND. MODELS HAVE BEEN CONSISTENT IN PUSHING A WARM FRONT NORTHWARD INTO/ACROSS THE AREA FRIDAY NIGHT THROUGH SATURDAY. INCREASING 850MB MOISTURE TRANSPORT INTO/OVER THE WARM FRONT IS EXPECTED TO FUEL SCATTERED THUNDERSTORM ACTIVITY. NAM SHOWING MUCAPE OF 1500-2000J/KG LATE FRIDAY NIGHT INTO SATURDAY MORNING WITH 0-3KM SHEAR OF 20-25KT. SO...LOOKS LIKE WE HAVE THE POTENTIAL TO GET A FEW STRONGER/MAINLY PULSE TYPE THUNDERSTORMS AHEAD OF THE FRONT AS IT PUSHES NORTH INTO/THROUGH THE AREA. THE FRONT LOOKS LIKE IT WILL PUSH NORTH OF THE AREA BY LATE MORNING...LEAVING OUR AREA IN A WEAKLY CAPPED ENVIRONMENT WITH WARM/HUMID AIRMASS IN PLACE. MAY HAVE TO WATCH CLOSELY FOR SEVERE THUNDERSTORM POTENTIAL DURING THE AFTERNOON WHERE NAM IS PRODUCING MUCAPE IN THE 3000-5000J/KG RANGE ALONG WITH 0-3KM BULK SHEAR OF 25-30KT. NAM INSTABILITY MAY BE A BIT OVERDONE BASED ON 70 DEGREE OUTPUT DEWPOINTS...BUT LOWER/MID 60S DEW POINTS LOOK REALISTIC WHICH WOULD YIELD CAPE IN THE 2000-4000J/KG. LOOKS LIKE HIGHEST SEVERE POTENTIAL WOULD BE WESTERN PORTIONS OF THE AREA WHERE STEEPER MID-LEVEL LAPSE RATES/HIGHER-END OF THE BULK SHEAR WILL EXIST. OTHERWISE...LOOK FOR HIGHS IN THE UPPER 70S TO THE LOWER 80S. SHOWERS AND THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE FROM WEST TO EAST SATURDAY NIGHT THROUGH SUNDAY AS FAIRLY STRONG SURFACE CYCLOGENESIS TAKES PLACE OVER THE NORTHERN PLAINS...FUELING STRONGER MOISTURE TRANSPORT/LIFT INTO THE AREA. CANNOT RULE OUT A FEW STRONG TO SEVERE STORMS OVER WESTERN PORTIONS OF THE AREA SATURDAY NIGHT IN DEEP SHEAR/HIGHER CAPE ENVIRONMENT. STRONG TO SEVERE STORM THREAT CONTINUES SUNDAY AS A COLD FRONT PUSHES INTO THE AREA. EXTENT OF SEVERE THREAT WILL BE DEPENDENT OF HOW MUCH THE ATMOSPHERE CAN RECOVER FROM ONGOING CONVECTION AND TIMING OF THE FRONT. WILL CONTINUE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES SUNDAY ARE EXPECTED TO TOP OFF IN THE MIDDLE/UPPER 70S. AFTER THIS...BEGINNING OF THE NEW WORK WEEK LOOKS COOLER/DRIER BEHIND THE DEPARTING LOW/COLD FRONT. PLAN ON HIGHS MONDAY AND TUESDAY IN THE UPPER 50S TO THE LOWER 60S. SHOWER/THUNDERSTORM CHANCES SPREAD INTO THE AREA AGAIN BY WEDNESDAY IN WARM AIR ADVECTION AHEAD OF A TROUGH PUSHING OUT OF THE PLAINS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 630 AM CDT THU MAY 14 2015 MAIN AVIATION CONCERNS ARE MVFR/IFR CEILING CONDITIONS AND SHOWERS MOVING INTO THE RST/LSE TAF SITES TODAY AND CONTINUE INTO TONIGHT. AN UPPER LEVEL DISTURBANCE OVER NORTHEAST KANSAS...NORTHWEST MISSOURI AND SOUTHWEST IOWA WILL LIFT NORTHEAST INTO THE GREAT LAKES REGION TONIGHT. SOUTHERLY WINDS OUT AHEAD OF THE DISTURBANCE WILL ADVECT LOW LEVEL MOISTURE INTO THE REGION AND LOWER CEILING HEIGHTS TODAY AT THE LSE/RST TAF SITES. THE LATEST 14.06Z NAM AND 14.09Z RAP SHOW CEILING HEIGHTS LOWERING TO IFR CONDITIONS AT RST TAF SITE BY 21Z TODAY AND TO MVFR AT LSE BY 23Z TODAY. WITH THE UPPER LEVEL DISTURBANCE PULLING AWAY TO THE EAST OF THE AREA AND LIGHT RAIN/SHOWERS ENDING TONIGHT...THE LATEST 14.06Z GFS/NAM HINT AT IMPROVING CONDITIONS AT RST/LSE TAF SITES AFTER 06Z FRIDAY. HOWEVER...THE 14.06Z GFS/NAM BUFKIT SOUNDINGS INDICATE NEAR SURFACE BOUNDARY LAYER RESIDUAL MOISTURE DURING THIS TIME FRAME. WILL CONTINUE TREND OF MVFR/IFR CEILING CONDITIONS AT RST/LSE TAF SITES AFTER 06Z FRIDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
551 AM MDT THU MAY 14 2015 .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 300 AM MDT THU MAY 14 2015 FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LLVL MOISTURE IS NOT ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z. UPPER LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE EJECTS NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER CALIFORNIA. WITH GOOD MIDLVL ISENTROPIC ASCENT AND SOME ELEVATED CAPE...THIS IS ACTUALLY A SITUATION WHERE SHOWER AND TSTM COVERAGE COULD BE GREATER INTO THE NIGHT...ESPECIALLY OVER THE NORTHEASTERN HALF OF THE CWA. THUS...KEPT THE 30-40 POPS GOING THROUGH EARLY FRI MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE TO ADVECT HIGHER DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT. THE MOST IMPACTFUL EVENT IN THE SHORT TERM IS STILL LOOKING LIKE THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI. OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS THIS WOULD PUSH THE SVR THREAT INTO SOUTHEAST WY. WHILE LARGE HAIL WOULD LIKELY BE THE PRIMARY THREAT...THE LLVL SHEAR PARAMETERS DO SHOW THE POTENTIAL FOR SOME WEAK TORNADOES ESPECIALLY ALONG AND JUST NORTH OF THE WARM FRONT WHERE WINDS WILL BE BACKED THE MOST. NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3 KM HELICITY OF 250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2 SPC OUTLOOK HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A SLIGHT RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO NORTH PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE SFC LOW AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE A BIT LESS LLVL MOISTURE AND INSTABILITY TO WORK WITH ON SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A COLD FRONT PUSHING ACROSS THE REGION. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 300 AM MDT THU MAY 14 2015 AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG /NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LLVL UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LLVL FORCING BENEATH INCREASINGLY DIFLUENT FLOW ALOFT AND A COUPLED H25 JET. THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM ADVECTION IN LLVL EASTERLY/UPSLOPE FLOW MAKES THIS QUESTIONABLE AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO SEE PCPN CHANGE TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST FOR HIGHER ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST VIRTUALLY EVERY DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES EACH AFTN THROUGH WED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 545 AM MDT THU MAY 14 2015 AREAS OF FOG WILL CONTINUE TO RESULT IN LOCALIZED IFR CONDITIONS AT KAIA/KBFF THROUGH ABOUT 13-14Z. OTHERWISE VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS THROUGH MUCH OF THE DAY. SHOWER AND TSTM CHANCES WILL INCREASE AFTER 19Z OVER SOUTHEAST WY...AND THEN AFTER 00Z FRI OVER WESTERN NE. CONVECTION COULD BE ACCOMPANIED BY GUSTY AND ERRATIC WINDS AND LOCALLY MVFR CIGS/VSBYS. LOW CIGS SHOULD BECOME MORE WIDESPREAD OVER THE WESTERN PANHANDLE BETWEEN 06-12Z FRI. && .FIRE WEATHER... ISSUED AT 300 AM MDT THU MAY 14 2015 NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO 25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL GREEN UP AFTER THE RECENT WET PERIOD. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...CLH AVIATION...CLH FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 AM MST THU MAY 14 2015 .SYNOPSIS...STRONG AND GUSTY WINDS WILL OCCUR INTO FRIDAY AHEAD OF A STRONG LOW PRESSURE SYSTEM APPROACHING FROM THE WEST. THIS SYSTEM WILL ALSO BRING A GOOD CHANCE OF SHOWERS...ISOLATED THUNDERSTORMS AND COOLER TEMPERATURES FRIDAY INTO SATURDAY. EXPECT DRY CONDITIONS AND MUCH WARMER TEMPERATURES EARLY NEXT WEEK. && .DISCUSSION...IR/VISIBLE SATELLITE IMAGERY INDICATED MOSTLY CLOUDY SKIES DUE TO CIRRIFORM CLOUDS FROM THE TUCSON METRO AREA EWD TO THE NEW MEXICO BORDER. CLEARING SKIES WERE NOTED ACROSS THE TOHONO O`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
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
908 AM PDT THU MAY 14 2015 .SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK. TEMPERATURES WILL BE COOLER THAN NORMAL THROUGH THE PERIOD. && .DISCUSSION...AS OF 9:08 AM PDT THURSDAY...LOCAL RADAR IS SHOWING SHOWERS OVER THE COASTAL WATERS THAT ARE SLOWLY MOVING EASTWARD TOWARDS THE COAST. THERE HAVE BEEN A FEW LIGHTNING STRIKES WEST OF THE MONTEREY/SAN LUIS OBISPO COUNTY LINE DURING THE PAST HOUR. EXPECT SHOWER ACTIVITY TO MOVE ONSHORE LATER THIS MORNING WITH A SLIGHT CHANCE OF THUNDERSTORMS THROUGH THE EVENING. RAINFALL TOTALS ARE NOT EXPECTED TO BE LARGE...UP TO A THIRD OF AN INCH IS POSSIBLE...BUT COULD TOP OUT AROUND A HALF INCH IN AREAS OF HEAVIER SHOWERS...MAINLY OVER COASTAL MONTEREY COUNTY. THE HRRR IS STILL INDICATING VERY SPOTTY RAINFALL AMOUNTS WITH SOME AREAS IN THE EAST BAY POSSIBLY GETTING UP TO A HALF INCH. THE MOST LIKELY SCENARIO IS A FEW SPOTS WILL GET MUCH MORE THAN EXPECTED WHILE OTHER PLACES GET LITTLE TO NO RAINFALL. SHOWERS ARE EXPECTED TO LINGER INTO THE OVERNIGHT HOURS AND SLOWLY DIMINISH ON FRIDAY. THE UPPER LOW WILL CONTINUE TO MOVE TO THE SOUTH ON FRIDAY WITH RAIN MOVING INLAND OVER THE LOS ANGELES BASIN FRIDAY MORNING. OUR AREA WILL SEE COOL TEMPERATURES THROUGH THE WEEKEND AS A LONG-WAVE TROUGH REMAINS OVER THE WEST. THIS TROUGH PATTERN WILL MAINTAIN THROUGH NEXT WEEK AS WELL WITH A FEW IMPULSES MOVING THROUGH FROM TIME TO TIME. RIGHT NOW NONE OF THESE ARE EXPECTED TO BRING ANY PRECIPITATION TO THE AREA...HOWEVER...COOLER THAN NORMAL TEMPERATURES WILL BE THE RULE. && .AVIATION...AS OF 4:30 AM PDT THURSDAY...CLOUDS ARE LOWERING WITH THE APPROACH OF AN UPPER LEVEL LOW. RADAR IS STARTING TO DETECT LIGHT SHOWERS OFF THE COAST AND THESE WILL MOVE INTO THE COAST BY MID MORNING AND INLAND LATE MORNING. WINDS WILL BE LIGHT SOUTHERLY THIS MORNING BUT WILL SWITCH TO WESTERLY IN THE AFTERNOON. VICINITY OF KSFO...MVFR CIGS. SHOWERS AFTER 16Z. SOUTHEAST WINDS 5-10 KT SWITCHING TO THE WEST AFTER 20Z. CLOUDS DECREASING AFTER 02Z. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...MVFR CIGS. SHOWERS AFTER 15Z. CLOUDS DECREASING AFTER 01Z. && .MARINE...AS OF 08:21 AM PDT THURSDAY...A 1010 MB LOW OFF THE NORTHERN CALIFORNIA COAST WILL TRACK SOUTHWARD BRINGING A SLIGHT CHANCE OF THUNDERSTORMS TODAY AND TONIGHT. NORTHWEST WINDS WILL INCREASE FRIDAY AND SATURDAY AS THE LOW MOVES INLAND OVER SOUTHERN CALIFORNIA AND HIGH PRESSURE BUILDS OFF THE CALIFORNIA COAST. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: SIMS AVIATION: W PI MARINE: LARRY 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 LINCOLN IL
207 PM CDT THU MAY 14 2015 .SHORT TERM...(TONIGHT) ISSUED AT 206 PM CDT THU MAY 14 2015 SHOWERS THUS FAR HAVE CONTINUED TO BATTLE A VERY DRY AIRMASS OVER CENTRAL ILLINOIS. HOWEVER...A MORE ROBUST AREA OF SHOWERS ASSOCIATED WITH THE UPPER LOW CURRENTLY TRACKING ACROSS NORTHERN MISSOURI WILL BE ARRIVING IN THE ILLINOIS RIVER VALLEY BY MID AFTERNOON. THE HRRR MODEL...WHICH HAS BEEN DOING A DECENT JOB THUS FAR...SHOWS SOME ADDITIONAL DEVELOPMENT WEST OF I-55 LATE AFTERNOON INTO THE EVENING... AND HAVE CONCENTRATED THE HIGHER POP`S IN THESE AREAS. HIGHER-RESOLUTION MODELS SUCH AS THE HRRR AND NMM/ARW AGREE WITH THE NAM SOLUTION OF THE EVOLUTION OF A MORE EAST-WEST CONFIGURATION OF SHOWERS ROUGHLY CENTERED ALONG I-72 BY MIDNIGHT. THUNDER UPSTREAM IN MISSOURI HAS BEEN MINIMAL THUS FAR...AND INSTABILITY PARAMETERS OFF THE NAM...RAP AND ARW SUGGEST ANY THUNDER IN OUR AREA WOULD BE MOST LIKELY ALONG AND WEST OF I-55 TONIGHT. NOT MUCH OF A DROPOFF EXPECTED IN TEMPERATURES TONIGHT...GENERALLY REMAINING STEADY IN THE LOWER 60S. && .LONG TERM...(FRIDAY THROUGH THURSDAY) ISSUED AT 206 PM CDT THU MAY 14 2015 IN THE WAKE OF THE WAVE MOVING ACROSS THE MIDWEST TODAY...HEIGHTS BUILD BRIEFLY AHEAD OF NEXT WEAKER WAVE MOVING NORTHEAST AROUND WEST COAST CLOSED LOW. HOWEVER, MODELS ARE CONSISTENT IN REDEVELOPING THE WARM FRONT OVER CENTRAL ILLINOIS FRIDAY AND WITH THE WEAKER WAVE APPROACHING FRIDAY AFTERNOON, THUNDERSTORMS WILL LIKELY DEVELOP. WILL NEED TO RETAIN AT LEAST LOW POPS DESPITE THE RIDGING. INSTABILITY OF 1500-2000 J/KG WILL BE POSSIBLE ALONG AND TO THE SOUTH OF THE FRONT IN AREAS THAT SEE A LITTLE SUN THOUGH SHEAR WILL BE QUITE LIMITED. AS SOUTHERLY FLOW BECOMES ESTABLISHED...DEW POINTS WILL RESPOND BY CLIMBING INTO THE 60S FOR FRIDAY AFTERNOON AND THE WEEKEND. AS THE WEST COAST ENERGY BEGINS TO PULL NORTHEAST TOWARD THE GREAT LAKES, WAVES WILL EJECT FROM THE SYSTEM AND PERIODICALLY CONTRIBUTE TO LIFT ALONG ANY CONVECTIVELY ENHANCED BOUNDARIES LYING ACROSS THE AREA. THIS WILL MAKE TIMING OF PRECIPITATION DIFFICULT UNTIL THE MAIN ENERGY PASSES NORTHWEST OF ILLINOIS ON SUNDAY. WILL HAVE TO GENERALLY BROADBRUSH GIVEN THE POTENTIAL INSTABILITY (1500-2500 J/KG) IN PLACE. 0-6KM SHEAR IS FORECAST TO REMAIN BELOW 20 KTS THROUGH SATURDAY EVENING, SO WIDESPREAD SEVERE WEATHER IS NOT EXPECTED THOUGH GIVEN THE HIGH PRECIPITABLE WATER WOULD NOT BE SURPRISED TO SEE SOME WET MICROBURST ACTIVITY PRODUCING GUSTY WINDS AT TIMES SATURDAY. THE MISSING INGREDIENT (DEEP SHEAR) JOINS THE ENVIRONMENT ON SUNDAY AS THE MAIN WAVE PASSES NORTHWEST OF ILLINOIS. 0-6KM SHEAR IS EXPECTED TO SURPASE 40 KTS BY SUNDAY EVENING. THERE DOES SEEM TO BE POTENTIAL FOR ROTATING UPDRAFTS GIVEN GFS FORECASTED 0-1KM HELECITY VALUES OF 125-150 M2/S2 AND LCL HEIGHTS BELOW 900 MB. STORM MOTION ALSO SUGGESTS THAT WINDS MAY BE A THREAT WITH FORECASTED STORM MOTION AROUND 40 KTS. THREAT WILL LIKELY INCREASE FROM SOUTHEAST TO NORTHWEST ACROSS FORECAST AREA DUE TO PROXIMITY OF THE WAVE. ASSOCIATED COLD FRONT IS EXPECTED TO PUSH THROUGH SUNDAY NIGHT AND MUCH COOLER TEMPERATURES ARE EXPECTED FOR THE BEGINNING OF THE WORK WEEK. STILL SOME SPREAD IN LATEST MODELS WITH REGARDS TO HOW MUCH COLD AIR WILL PENETRATE THE MIDWEST BEHIND FRONT WITH THE ECMWF COOLER THAN GFS/DGEX. HOWEVER, 12Z GFS IS TRENDING TOWARD THIS COOLER SOLUTION. WILL COMPROMISE BETWEEN THE TWO SOLUTIONS FOR NOW AND KEEP AT LEAST SOME LOW POPS IN FOR WED THROUGH THU. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1237 PM CDT THU MAY 14 2015 INITIAL BATCH OF SHOWERS HAS BEEN ERODING IN THE DRY AIR OVER CENTRAL ILLINOIS...BUT STEADIER SHOWERS ARE MOVING NORTHEAST THROUGH MISSOURI AND SHOULD AFFECT KPIA/KSPI TOWARD MID AFTERNOON. HAVE NOT MADE MUCH CHANGE TO THE CURRENT TAF SET THROUGH ABOUT 09Z...AS SCATTERED RAIN WILL CONTINUE TO DEVELOP THIS EVENING. HAVE REMOVED THUNDER MENTION AT KDEC/KCMI AS THE BETTER INSTABILITY SHOULD BE FURTHER TO THE WEST. STILL HAVE SOME CONCERNS WITH LLWS POTENTIAL IN THE 03-09Z TIME RANGE...BUT ENOUGH QUESTIONS REMAIN ON CONVECTIVE POTENTIAL TO HOLD OFF MENTION. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GEELHART LONG TERM...BARKER AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1237 PM CDT THU MAY 14 2015 .UPDATE... ISSUED AT 952 AM CDT THU MAY 14 2015 SHOWERS IN WEST CENTRAL ILLINOIS HAVE BEEN STRUGGLING TO MAKE ANY EASTWARD PROGRESS. OUR MORNING SOUNDING SHOWED VERY DRY AIR BELOW 15000 FEET...AND CEILINGS UNDERNEATH THE RAIN SHIELD ARE STRUGGLING TO GET MUCH BELOW 7000 FEET. RAP FORECAST SOUNDINGS KEEP IT PRETTY DRY BELOW 850 MB INTO THE AFTERNOON AND FOCUS MUCH OF THE RAIN ALONG AND WEST OF THE ILLINOIS RIVER. THIS WOULD BE ASSOCIATED WITH THE SHOWERS THAT ARE CURRENTLY STEADILY MOVING THROUGH CENTRAL AND SOUTHWEST MISSOURI. THE RADAR ECHOES MOVING OUT OF SOUTHWEST ILLINOIS ARE ALSO VERY LIGHT...AND THESE WILL BE MOVING INTO THE SOUTHEAST PART OF THE FORECAST AREA SHORTLY AFTER MIDDAY. HAVE SENT SOME UPDATED ZONES/GRIDS TO MAINLY REFINE THE RAIN TRENDS. && .SHORT TERM...(TODAY) ISSUED AT 319 AM CDT THU MAY 14 2015 1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE. .LONG TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 319 AM CDT THU MAY 14 2015 UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A CHANCE OF THUNDER ACROSS THE BOARD TONIGHT. ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE 60S. WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE MAY NEED TO BE REMOVED BY LATER SHIFTS. ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS DIPPING INTO THE 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1237 PM CDT THU MAY 14 2015 INITIAL BATCH OF SHOWERS HAS BEEN ERODING IN THE DRY AIR OVER CENTRAL ILLINOIS...BUT STEADIER SHOWERS ARE MOVING NORTHEAST THROUGH MISSOURI AND SHOULD AFFECT KPIA/KSPI TOWARD MID AFTERNOON. HAVE NOT MADE MUCH CHANGE TO THE CURRENT TAF SET THROUGH ABOUT 09Z...AS SCATTERED RAIN WILL CONTINUE TO DEVELOP THIS EVENING. HAVE REMOVED THUNDER MENTION AT KDEC/KCMI AS THE BETTER INSTABILITY SHOULD BE FURTHER TO THE WEST. STILL HAVE SOME CONCERNS WITH LLWS POTENTIAL IN THE 03-09Z TIME RANGE...BUT ENOUGH QUESTIONS REMAIN ON CONVECTIVE POTENTIAL TO HOLD OFF MENTION. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEELHART SHORT TERM...BARNES LONG TERM...BARNES AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
205 PM EDT THU MAY 14 2015 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EDT THU MAY 14 2015 WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL... STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 1013 AM EDT THU MAY 14 2015 ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION FOLLOWS... ISSUED AT 329 AM EDT THU MAY 14 2015 HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE MID 40S TO THE MID 50S. THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO VALLEY AHEAD OF IT. EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL CONTINUE WITH A DRY FORECAST TODAY. TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS GUIDANCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 329 AM EDT THU MAY 14 2015 FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE PERIOD. UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED. SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40 POPS OVER THE ENTIRE FORECAST AREA. REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT. TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... ISSUED AT 205 PM EDT THU MAY 14 2015 ENSEMBLES AND DETERMINISTIC MODELS CONTINUE TO SUGGEST A WARM AND UNSETTLED START TO THE EXTENDED. THE DETERMINISTIC 12Z GFS AND 00Z ECMWF ALONG WITH THE ENSEMBLE MEANS ARE IN VERY GOOD AGREEMENT REGARDING THE SYNOPTIC PATTERN FOR THE EXTENDED. THEY LIFT AN UPPER LOW...CURRENTLY OFF THE CALIFORNIA COAST...NORTHEAST TO ONTARIO ON MONDAY. THIS WILL ALLOW A FRONTAL SYSTEM TO SWEEP SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY. THE FRONT WILL INTERACT WITH WARM...MOIST AND UNSTABLE AIR AND TRIGGER SCATTERED TO NUMEROUS THUNDERSTORMS SUNDAY NIGHT AND MONDAY...BEFORE COOLER AND DRY WEATHER RETURN UNDER THE INFLUENCE OF STRONG HIGH PRESSURE BUILDS IN FROM THE WEST. REGIONAL BLEND POPS HANDLE THIS WELL WITH GOOD CHANCE POPS SUNDAY NIGHT INTO MONDAY AND DRY BY MONDAY NIGHT. TO WRAP UP THE EXTENDED...A WEAK SOUTHERN SYSTEM COULD BRING A FEW SHOWERS OR STORMS TO THE AREA BY NEXT THURSDAY. TEMPERATURES SHOULD START OFF ABOVE NORMAL AHEAD OF THE COLD FRONT AND THEN FALL TO BELOW NORMAL BEHIND THE FRONT WITH HIGHS ONLY IN THE 60S LOOKING GOOD BY TUESDAY PER THE REGIONAL BLEND. && .AVIATION /DISCUSSION FOR THE 141800Z TAF ISSUANCE/... ISSUED AT 1215 PM EDT THU MAY 14 2015 GOOD CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY EXCEPT PERHAPS BRIEF MVFR TOWARD 12Z IN SCATTERED SHOWERS OR THUNDERSTORMS. SHOULD BE DRY THROUGH AT LEAST 04Z ACROSS THE TERMINALS...AND CONFIDENCE IS NOT GOOD ON TIMING A TEMPO GROUP THAT FAR OUT AT ANY ONE AIRPORT...SO WILL JUST TREND TOWARDS INCREASING AFTERNOON MID DECK AND INCREASING OVERNIGHT CU DECK. WINDS WILL START OFF SOUTHEAST AND THEN VEER TO SOUTH AND SOUTHWEST TONIGHT AND FRIDAY. SPEEDS LOOK TO BE 10 KNOTS OR LESS BUT THEN UP TO 15 KNOTS AFTER 14Z FRIDAY WITH GUSTS TO 20. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...RYAN NEAR TERM...MRD/RYAN SHORT TERM...RYAN LONG TERM....MK AVIATION...MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1215 PM EDT THU MAY 14 2015 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EDT THU MAY 14 2015 WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL... STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... ISSUED AT 1013 AM EDT THU MAY 14 2015 ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION FOLLOWS... ISSUED AT 329 AM EDT THU MAY 14 2015 HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE MID 40S TO THE MID 50S. THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO VALLEY AHEAD OF IT. EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL CONTINUE WITH A DRY FORECAST TODAY. TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS GUIDANCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 329 AM EDT THU MAY 14 2015 FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE PERIOD. UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED. SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40 POPS OVER THE ENTIRE FORECAST AREA. REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT. TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 329 AM EDT THU MAY 14 2015 ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK. WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY FORECAST AFTER MONDAY. && .AVIATION /DISCUSSION FOR THE 141800Z TAF ISSUANCE/... ISSUED AT 1215 PM EDT THU MAY 14 2015 GOOD CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY EXCEPT PERHAPS BRIEF MVFR TOWARD 12Z IN SCATTERED SHOWERS OR THUNDERSTORMS. SHOULD BE DRY THROUGH AT LEAST 04Z ACROSS THE TERMINALS...AND CONFIDENCE IS NOT GOOD ON TIMING A TEMPO GROUP THAT FAR OUT AT ANY ONE AIRPORT...SO WILL JUST TREND TOWARDS INCREASING AFTERNOON MID DECK AND INCREASING OVERNIGHT CU DECK. WINDS WILL START OFF SOUTHEAST AND THEN VEER TO SOUTH AND SOUTHWEST TONIGHT AND FRIDAY. SPEEDS LOOK TO BE 10 KNOTS OR LESS BUT THEN UP TO 15 KNOTS AFTER 14Z FRIDAY WITH GUSTS TO 20. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...RYAN NEAR TERM...MRD/RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1248 PM CDT THU MAY 14 2015 .SYNOPSIS... ISSUED AT 312 AM CDT THU MAY 14 2015 AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN 2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION SHOULD CONTINUE TO BE SEEN. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CDT THU MAY 14 2015 TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z. HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10 PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY. TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT. MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700 PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH. ERVIN .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 312 AM CDT THU MAY 14 2015 FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S. THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500 J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD. CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST. THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN. HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK 850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI. SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER THAN FRIDAY AS WELL. SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE ISOLATED. FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION VECTORS AND PWAT VALUES NEAR 1.50 INCHES. SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE SFC COLD FRONT. MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1235 PM CDT THU MAY 14 2015 VFR CIGS WILL BE ERODING FROM THE SOUTHWEST AS RAIN AND SATURATION PROCESSES MOVE INTO THE TAF SITES. MORE SUBSTANTIAL RAIN MAY STILL NOT GET INTO THE DBQ VCNTY UNTIL LATE AFTERNOON. HEAVIER SHOWERS WITH SOME EMBEDDED THUNDER NOW IN CENTRAL TO NORTHEASTERN MO WILL IMPACT THE BRL TO MLI SITES AFTER 2 PM AND INTO THE EVENING WITH MVFR CIGS AND VSBYS. AREAS OF RAIN THEN TO PERSIST THROUGH LATE EVENING/10 PM CDT...BEFORE DIMINISHING. THEN AS A WEAK BOUNDARY MOVES ACRS THE AREA...SFC WINDS MAY GO LIGHTER SOUTH TO SOUTHWEST LATE TONIGHT. WITH MORE LLVL MOISTURE BEING ADVECTED UP ACRS THE REGION...THESE LIGHTER WINDS MAY ALLOW FOR IFR CIGS AND VSBYS FROM FOG TO FORM AFTER MIDNIGHT AND INTO EARLY FRI MORNING AT ALL TAF SITES EXCEPT MAYBE FOR DBQ. A LOW CHC FOR MORE SCTRD SHOWERS/ THUNDERSTORMS TO FESTER ALONG AND SOUTH OF THE BRL SITE LATE TONIGHT. LIGHT SOUTHEAST TO SOUTHWEST WINDS FRI MORNING MAY NOT INCREASE/MIX ENOUGH TO HELP VSBYS AND CIGS IMPROVE UNTIL AFTER 15Z. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...ERVIN SHORT TERM...ERVIN LONG TERM...UTTECH AVIATION...12
AREA FORECAST DISCUSSION
NWS PADUCAH KY
316 PM CDT THU MAY 14 2015 .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 254 PM CDT THU MAY 14 2015 ALTHOUGH MID-LEVEL REGION OF THE RIDGE WEAKENED FURTHER EAST THAN ANTICIPATED IN THE WAKE OF THE EJECTING SHORTWAVE TROUGH TO THE NORTH AND NORTHEAST...SUBSIDENCE SHOULD BUILD BACK IN THIS EVENING WITH A SMALLER AMPLITUDE RIDGE ALOFT. THIS SUBSIDENCE WILL BE SHORT LIVED AS THE NEXT SHORT WAVE ROTATING OUT OF THE ROCKIES MOVES INTO THE WFO PAH FORECAST AREA BY FRIDAY MORNING. ATTEMPTED TO DEPICT THE MINIMA ON POPS AND WEATHER IN THE GRIDS THIS EVENING...FOLLOWED BY A SMALL CHANCE OF RAIN CLOSER TO DAYBREAK AHEAD OF A WEAK LOW/MID LEVEL TROUGH AXIS EMBEDDED IN A MEAN SOUTHWEST FLOW ALOFT. FROM FRIDAY THROUGH SATURDAY NIGHT...A TRAIN OF SMALL AND TRANSIENT SHORTWAVE IMPULSES WILL WORK THROUGH THE WFO PAH FORECAST AREA. THE VARIABILITY IS GOING TO MAKE IT DIFFICULT TO GO MUCH BEYOND CHANCE CATEGORY THROUGH FRIDAY NIGHT. THE INFLUENCE WILL INITIALLY BE DIURNAL...BUT WEAK FORCING WILL DOMINATE SATURDAY AND SATURDAY NIGHT IN THE WARM CONVEYOR BELT. HOWEVER...THE POP SIGNAL GETS MORE PERSISTENT SATURDAY AND SATURDAY NIGHT OVER EXTREME SOUTHERN ILLINOIS...MOST OF WEST KENTUCKY AND SOUTHEAST MISSOURI...AS THE MEAN ISENTROPIC LIFT ZONE REMAINS FOCUSED ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST. CHANNELED VORTICITY ORIENTED PARALLEL TO THE UPPER FLOW WILL MAINTAIN INTERMITTENT RAIN ACTIVITY THROUGH THE PERIOD. LEANED CLOSER TOWARD THE HIGHER RESOLUTION NAM-WRF DETERMINISTIC AND ENSEMBLE GUIDANCE...INCLUDING THE HRRR IN THE 06-18 HOUR TIME FRAME...WITH MORE EMPHASIS TOWARD THE ECMWF AND CANADIAN GUIDANCE TOWARD SATURDAY. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 254 PM CDT THU MAY 14 2015 00Z OPS MODELS AND EC/GFS ENSEMBLE MEAN SOLUTIONS REMAINED IN GOOD AGREEMENT WITH THE OVERALL UPPER AIR PATTERN. AT THE BEGINNING OF THE PERIOD...A MID LEVEL TROF WILL EJECT NEGATIVE TILT FROM THE PLAINS INTO THE UPPER MIDWEST SUNDAY. FRONT STILL OFF TO OUR WEST BUT WITH MOISTURE AND INSTABILITY PRESENT IN AN UNSETTLED SW FLOW ALOFT...CONTINUED WITH HIGH CHANCE POPS FOR CONVECTION. CONFIDENCE REMAINS ABOVE AVERAGE. FRONT WILL SETTLE SOUTH INTO THE AREA LATE SUNDAY NIGHT INTO MONDAY. LIKELY POPS SUNDAY NIGHT AND ESPECIALLY ACROSS THE SE 2/3 OF THE CWFA PER THE LATEST OUTPUT. WILL LINGER POPS MONDAY AS THE FRONT WILL CONTINUE TO PROGRESS SOUTHEAST ACROSS THE AREA. DIMINISHING POPS MONDAY EVENING...AND IT SHOULD BE DRY AFTER MIDNIGHT MONDAY NIGHT. HIGH PRESSURE SHOULD RESULT IN DRY WEATHER TUESDAY THROUGH TUESDAY NIGHT. THE OVERALL MID LEVEL FLOW PATTERN FLATTENS OUT ACROSS THE MID CONUS WITH A TROF OFF THE PACIFIC COAST AND OVER SE CANADA. THE GFS/ECMWF SOLUTIONS OF THE PAST DAY OR SO SUGGEST MODEST MID LEVEL SUPPORT AND MOISTURE MAY RESULT IN A FEW SHOWERS WEDNESDAY. THURSDAY IS MORE UNCLEAR. THE MODELS SHOW DECREASING MOISTURE WITH HIGH PRESSURE TRYING ONCE AGAIN TO BUILD SOUTHEAST. SO NO POPS FOR NOW THURSDAY. THE NEW ECMWF GUIDANCE TRENDED A BIT COOLER FOR MONDAY THROUGH WEDNESDAY. OTHERWISE A CONSENSUS OF THE GFS/GFS ENSEMBLE MOS AND PREVIOUS ECMWF NUMBERS WERE STEADY. WILL CONTINUE TO MONITOR THIS TREND. FOR NOW...JUST SLIGHT ADJUSTMENTS TO OUR EXISTING NUMBERS AND THE OVERALL MOS CONSENSUS FROM THE PAST 48 HOURS. && .AVIATION... ISSUED AT 1208 PM CDT THU MAY 14 2015 VERY LIGHT RAIN SHOWERS/SPRINKLES STILL MOVING SLOWLY EAST ACROSS THE AREA...SOME OF WHICH IS NOT HITTING THE GROUND. NOT PLANNING ON MENTION IN THE TAFS. OTHERWISE MAINLY HIGH CLOUDS WITH A FEW MID CLOUDS. VFR CONDITIONS THE RULE. LIGHT ESE WINDS WILL GRADUALLY VEER THROUGH 18Z FRIDAY...LIGHT THROUGH TONIGHT THEN SSW UP TO 10 KTS BY LATE MORNING FRIDAY. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ SHORT TERM...SMITH LONG TERM...CN AVIATION...CN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1253 PM CDT THU MAY 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 326 AM CDT THU MAY 14 2015 TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR HIGHS IN THE 70S TO 80 SOUTH. WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING SCATTERED TSTMS FROM 06Z ONWARD. INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 326 AM CDT THU MAY 14 2015 LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE. DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS. LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION. THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE. MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK NORTH AND EAST THROUGH THE EVENING. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7 RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR WIDESPREAD QPF AND STRONG MODEL CONSENSUS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1250 PM CDT THU MAY 14 2015 VFR CONDITIONS EXPECTED FOR THE AFTERNOON...ALTHOUGH CAN NOT RULE OUT A BRIEF MVFR CIG ACROSS NRN NEB EARLY. OVERNIGHT A DISTURBANCE WILL LIFT NORTHEAST ACROSS THE AREA...WITH A BAND OF THUNDERSTORMS EXPECTED. IMPACT TO SW NEB AFTER MIDNIGHT...THEN MOVING NORTHEAST THROUGH EARLY MORNING. THE THUNDERSTORMS WILL LIKELY BRING MVFR OR IFR CIGS THAT COULD LINGER AFTER THE THUNDERSTORMS LIFT INTO S DAKOTA. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MARTIN AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
732 AM CDT THU MAY 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT THU MAY 14 2015 ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3) TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK). STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM) WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID 0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS. LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN MOST PLACES. NOW LOOKING AHEAD FORECAST-WISE... EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO- NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST. HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE POP IS BELOW 20 PERCENT. WOULD NORMALLY BE A BIT MORE CONCERNED ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING. TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY. THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13 NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST BREEZES THIS MORNING WILL STEADILY BECOME MORE SOUTHWESTERLY IF NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT EXPECTED TO AVERAGE MORE THAN 10-15 MPH. THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN 1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE- MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST. COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500 J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61 DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY 1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE FOCUS REMAIN ON THE THUNDERSTORM CHANCES. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 420 AM CDT THU MAY 14 2015 A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS. OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK. STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR 60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO. AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY... EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER. CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID WEEK TO BE MORE ISOLATED ACROSS THE REGION. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 722 AM CDT THU MAY 14 2015 MVFR CONDITIONS ARE EXPECTED AT THE TERMINAL SITES THROUGH THE BEGINNING HOURS OF THE TAF FOR LOW CEILINGS...HOWEVER...LATER THIS AFTERNOON CONDITIONS SHOULD IMPROVE TO VFR HAS CLOUD BASES LIFT. WIND SPEEDS SHOULD ALSO GO LIGHT AND VARIABLE NEAR 00Z...WITH CONFIDENCE HIGH REGARDING MINIMAL IMPACTS AT THE TERMINALS WEATHER-WISE THOUGH MOST OF THE AFTERNOON/EVENING. CONFIDENCE BEGINS TO DECREASE WHEN WE STARTING TALKING ABOUT THUNDERSTORM POTENTIAL LATE TONIGHT INTO TOMORROW MORNING. CHANCES ARE THERE COULD BE SOME THUNDERSTORMS IN THE VICINITY OF THE TERMINALS...BUT CURRENT TRENDS APPEAR TO BE BACKING OFF THIS SCENARIO. THAT BEING SAID...THUNDERSTORMS ARE EXPECTED AFTER MIDNIGHT ACROSS THE AREA WITH CHANCES LOOKING TO BE CLOSER TO 12Z...WHICH IS LATER THAN THE PREVIOUS TAF INITIALLY SUGGESTED. CONFIDENCE IN THUNDERSTORM DEVELOPMENT AND COVERAGE SHOULD BECOME CLEARER WITH SUBSEQUENT TAFS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...ROSSI AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
951 AM PDT THU MAY 14 2015 .SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES. && .UPDATE...ONLY LINGERING LIGHT SHOWER ACTIVITY LEFT IN THE FAR NORTHERN LAS VEGAS VALLEY AND THE SHEEP RANGE. MODELS BRING ANOTHER ROUND OF SHOWERS TO THE VALLEY THIS AFTERNOON INTO THE EVENING INCLUDING POSSIBLE THUNDERSTORMS. VISIBLE SATELLITE SHOWS A BROAD DECK OF MID LEVEL CLOUDS OVER SAN BERNARDINO COUNTY AND MOHAVE COUNTY SPREADING NORTH AND PARTLY TO MOSTLY CLOUDY CONDITIONS ARE EXPECTED THROUGH THE DAY WHICH WILL LIKELY LIMIT DAYTIME HEATING IN MOST AREAS. SCATTERED SHOWERS AND ISOLATED STORMS ARE EXPECTED TODAY AS SHORTWAVE ENERGY AHEAD OF LOW PRESSURE OFF THE WEST COAST EJECTS INLAND ACROSS THE CWA. -SALMEN-&& .AVIATION... FOR MCCARRAN...A DENSE BAND OF MID LEVEL CLOUDS ARE SPREADING ACROSS THE VALLEY AND BKN CLOUDS GENERALLY AOA 15K FEET ARE EXPECTED BEFORE SHOWERS REDEVELOP THIS AFTERNOON. SOUTH WINDS OF 15-25KT TO CONTINUE WITH GUSTS TO 30KTS POSSIBLE. SOME VARIABILITY IN WIND SPEED/DIRECTION POSSIBLE WHEN SHOWERS MOVE THROUGH THE VALLEY LATER THIS AFTERNOON. CIGS IN THE 8-10K FT RANGE THIS IS EXPECTED LATER THIS AFTERNOON AND EVENING WITH LOW CIGS POSSIBLE IN RAIN. -SALMEN- FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE. BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED. && .PREV UPDATE...809 AM PDT...A QUICK UPDATE TO ADD SHOWERS/STORMS TO PORTIONS OF CLARK COUNTY INCLUDING THE LV VALLEY UP THROUGH LINCOLN COUNTY BASED ON LATEST RADAR TRENDS AND LIGHTNING DATA. -SALMEN- && .PREVIOUS DISCUSSION...256 AM PDT... .SHORT TERM...THROUGH SATURDAY NIGHT. THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS THE MOJAVE DESERT. WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON. WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE... BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH. WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST ANY WIND HEADLINES. BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH. FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL AVERAGES. ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY BUT STILL BE AROUND 15 DEGREES BELOW NORMAL. .LONG TERM...SUNDAY THROUGH THURSDAY. SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON. THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND. && .SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ SHORT TERM/AVIATION...OUTLER LONG TERM...ADAIR FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1155 AM MDT THU MAY 14 2015 .AVIATION... 18Z TAF CYCLE ISOLD SH/TS WILL IMPACT NW/NC AND PERHAPS EASTERN PORTIONS OF THE FORECAST AREA THROUGH THE EARLY/MID EVENING HRS. LIKELY IMPACTS WOULD BE TO FMN/LVS WITH POSSIBLE IMPACTS TO GUP/TCC. THE IMPACTS ARE NOT EXPECTED TO BE TOO SIGNIFICANT OTHER THAN TO FMN WHERE A TEMPO TS IS USED. WILL MONITOR THAT TREND BECAUSE MAYBE TOO BULLISH WITH THAT SCENARIO. THE NEXT ROUND OF SH SHOULD NOT SIGNIFICANTLY IMPACT TERMINAL SITES UNTIL AFTER 18Z FRI. WIND FLOW WILL INCREASE AND ABQ COULD EXPERIENCE PERIODIC GUSTS NEAR 35 KT LATER THIS AFTERNOON. UNSURE ABOUT AN AWW AT THIS TIME. WILL BE SOMEWHAT DEPENDENT ON CLEARING CLOUD COVER. OTHER SITES WILL SEE GUSTS BETWEEN 30-35 KT AT TIMES...GUP/AEG AND LVS. LVS/GUP SHOULD EXPERIENCE THE HIGHEST WIND VALUES THIS AFTERNOON AND CANT RULE OUT HIGHER GUSTS. MTN TOP OBSCD WILL BE THE MAIN IMPACTS DUE TO PASSING SHOWERS ACROSS THE NORTH. 50 && .PREV DISCUSSION...330 AM MDT THU MAY 14 2015... .SYNOPSIS... ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE. SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY. && .DISCUSSION... WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT. SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7 WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY. && .FIRE WEATHER... A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY... PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA. STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH. BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS... MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED. ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD. 43 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
141 PM CDT THU MAY 14 2015 .UPDATE... ISSUED AT 142 PM CDT THU MAY 14 2015 MAIN UPDATE WAS TO SKY AND TEMPERATURES. LOW STRATUS PERSISTING ACROSS THE WEST. LAST FEW RUNS OF THE HRRR STILL TRENDS MOSTLY SUNNY...JUST WILL BE A BIT LATER THAN PREVIOUSLY THOUGHT. THIS IMPACTED DAYTIME HIGHS ACROSS THE WEST...LOWERING A FEW DEGREES. UPDATE ISSUED AT 1029 AM CDT THU MAY 14 2015 SURFACE LOW PRESSURE CENTERED OVER WESTERN NEBRASKA WITH A QUASI- STATIONARY SURFACE FRONT EXTENDING FROM THE LOW NORTH-NORTHEAST ACROSS THE CENTRAL DAKOTAS INTO NORTHEASTERN NORTH DAKOTA. STRONG MID LEVEL S/WV TROUGH LIFTING ACROSS THE EASTERN DAKOTAS TOWARDS THE UPPER MISSISSIPPI VALLEY REGION. SHOWERS...SOME AREAS MODERATE...CONTINUE ALONG THE FRONTAL ZONE ACROSS SOUTH CENTRAL NORTH DAKOTA INTO NORTHEASTERN NORTH DAKOTA THIS MORNING. RAINFALL AMOUNTS WITHIN THE BAND HAVE GENERALLY BEEN IN THE RANGE OF 0.5-0.75"...WITH AMOUNTS IN EARLIER CONVECTIVE BANDS IN EXCESS OF AN INCH. SHOWERS WILL CONTINUE TO SLOWLY LIFT NORTH AND EAST AS THE DAY PROGRESSES...AND SHOULD BE ENTIRELY OUT OF MY EASTERN COUNTIES BY 03Z. OTHER UPDATE WITH THIS FORECAST PACKAGE WAS TO LOWER TEMPERATURES CENTRAL AS LOW CLOUD COVER IS NOW FORECAST TO PERSIST THROUGH THE AFTERNOON AS PER THE LAST FEW HIGH RES HRRR MODEL RUNS ALONG WITH THE LATEST NAM/RAP LOW LEVEL RH FORECAST. STILL EXPECT CLEARING WEST...THOUGH STRATUS FIELD IS EXTENSIVE. HIGH RES MODELS INDICATE OVC CIGS TRENDING FEW-SCT 16-19Z ACROSS MY WEST...SO WILL MONITOR IN CASE CLOUD COVER NEEDS TO BE INCREASED AND TEMPS DROPPED. UPDATE ISSUED AT 640 AM CDT THU MAY 14 2015 SHOWERS CONTINUE TO LIFT SLOWLY NORTHWARD ACROSS CENTRAL AND EASTERN NORTH DAKOTA. LATEST BOWMAN RADAR SHOWS RETURNS DRYING UP OVER WESTERN NORTH DAKOTA...THUS CURRENT RADAR TRENDS LOOK GOOD. OTHERWISE NO SIGNIFICANT UPDATES TO THE CURRENT FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 346 AM CDT THU MAY 14 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE WIDESPREAD SHOWERS TODAY WITH SOME AREAS CENTRAL SEEING HEAVY RAINFALL. CURRENTLY...AN UPPER LEVEL LOW/SHORTWAVE LIFTING NORTHEAST THROUGH THE CENTRAL AND NORTHERN PLAINS WAS ASSOCIATED WITH WIDESPREAD SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ACROSS THE STATE. LIGHTNING ACTIVITY HAD DECREASED IN THE LAST HOUR...AND MESOANALYSIS INDICATES THAT CAPE HAS DECREASED ACROSS THE REGION. AT THE SURFACE...LOW PRESSURE WAS OVER WYOMING WITH A WARM FRONT EXTENDING FROM THE LOW NORTHEASTWARD TO NEAR FORT YATES TO NEAR DEVILS LAKE TO THE NORTHEAST CORNER OF NORTH DAKOTA. FORECAST CAPE VALUES FOR TODAY ARE LOW ENOUGH TO KEEP THE MENTION OF THUNDER OUT OF THE FORECAST FOR THE DAYTIME PERIOD. PRECIPITABLE WATER FORECASTS OF 1.00" TO 1.20" FOR SOUTH CENTRAL NORTH DAKOTA...ALONG THE SURFACE WARM FRONT. WIDESPREAD AREAS OF 0.50" OF RAIN ARE POSSIBLE TODAY ALONG AND EAST OF A LINE FROM THE TURTLE MOUNTAINS TO BISMARCK/MANDAN TO GRANT COUNTY. LOCALLY HIGHER AMOUNTS ARE POSSIBLE. THE UPPER LEVEL SHORTWAVE AND SURFACE WARM FRONT ARE PROGGED TO MOVE EAST TODAY. EXPECT SHOWERS TO DECREASE FROM WEST TO EAST TODAY...LINGERING IN CENTRAL NORTH DAKOTA THIS AFTERNOON BEFORE TAPERING OFF DURING THE EVENING HOURS. AS THE SURFACE WARM FRONT MOVES EAST...HIGH PRESSURE IN SOUTH CENTRAL CANADA WILL PUSH SOUTHWARD INTO THE STATE. HIGHS TODAY SHOULD RANGE IN THE 50S TO LOWER 60S...WITH LOWS TONIGHT FROM THE UPPER 30S TO MID 40S. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 346 AM CDT THU MAY 14 2015 STRONG VERTICALLY STACKED SYSTEM WILL INFLUENCE THE WEATHER ACROSS THE NORTHERN PLAINS FRIDAY THROUGH SUNDAY. MAIN FORECAST ISSUES IN THE LONG TERM ARE SEVERE POTENTIAL ON SATURDAY...PRECIPITATION AMOUNTS AND POSSIBLE LOCALIZED FLOODING ISSUES THROUGH THE WEEKEND AND THE POTENTIAL FOR FREEZING TEMPERATURES MONDAY TUESDAY MORNINGS ON THE BACK SIDE OF THIS SYSTEM. WE START OFF ON A QUIET NOTE FRIDAY AS THE UPPER LEVEL SYSTEM TRACKS ACROSS THE INTER-MOUNTAIN WEST AND BEGINS TO TAKE SHAPE OVER THE NORTHERN HIGH PLAINS. WE BEGIN THE DAY DRY WITH SURFACE HIGH PRESSURE OVER THE FORECAST AREA. SOUTHEAST FLOW ALOFT WILL INCREASE OVER WESTERN NORTH DAKOTA AS CYCLOGENESIS TAKES PLACE OVER THE NORTHERN AND CENTRAL HIGH PLAINS. PRECIPITATION IS EXPECTED TO DEVELOP BY AFTERNOON OVER THE SOUTHWEST AND BEGIN TO SPREAD NORTH AND EAST. FRIDAY NIGHT THROUGH SATURDAY MORNING...STRONG WARM ADVECTION ENVELOPES WESTERN AND CENTRAL NORTH DAKOTA WITH A SURFACE AND UPPER LOW DEVELOPING OVER NORTHEAST MONTANA. MODELS ARE PRETTY SIMILAR IN BRINGING A BAND OF PRECIPITATION SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY MORNING...WITH THE MAJORITY OF THE PRECIPITATION OVER THE NORTHERN TIER COUNTIES ALONG THE DEFORMATION ZONE BY MIDDAY SATURDAY. INSTABILITY ALOFT IS LIMITED INITIALLY BUT IS EXPECTED TO INCREASE DURING THE NIGHT ACROSS NORTHERN SOUTH DAKOTA INTO SOUTHERN NORTH DAKOTA. MOST UNSTABLE CAPES OF 500-1000 J/KG WITH 20-40KTS OF 0-6KM SHEAR LAY ACROSS THE NORTHERN SOUTH DAKOTA BORDER LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING. THUS A THREAT OF SEVERE WEATHER CAN NOT BE RULED OUT DURING THIS PERIOD...BUT EXPECT THE BETTER THREAT WILL REMAIN SOUTH OF THE BORDER. SATURDAY AFTERNOON...POSSIBLY AS EARLY AS LATE SATURDAY MORNING THE FIRST WAVE OF PRECIPITATION WILL HAVE MOVED THROUGH AND MODELS SUGGEST A DRY SLOT WORKING INTO CENTRAL NORTH DAKOTA AS AN 80 KT UPPER LEVEL JET PUSHES INTO EASTERN NORTH DAKOTA BY AROUND MIDDAY SATURDAY. THIS SHOULD ALLOW FOR A DESTABILIZING ATMOSPHERE DURING THE LATE MORNING AND AFTERNOON AS SURFACE TEMPERATURES RISE INTO THE 70S ACROSS THE SOUTHERN HALF OF THE STATE. A STRONG SOUTHERN STREAM JET OVER THE SOUTHWEST U.S. BEGINS LIFTING INTO THE SOUTHERN AND CENTRAL PLAINS...ALLOWING THE NORTHERN STACKED SYSTEM OVER EASTERN MONTANA TO BEGIN MOVING EAST. ALTHOUGH DIRECTIONAL SHEAR IS NOT IMPRESSIVE...SUFFICIENT BULK SHEAR AND CAPE WILL BE AVAILABLE DURING THE LATE MORNING THROUGH THE AFTERNOON THAT SEVERE STORMS ARE POSSIBLE. WILL STILL NEED TO MONITOR TRENDS OF THE NEXT DAY OR SO TO HOPEFULLY GET A BETTER IDEA. SATURDAY NIGHT THROUGH SUNDAY...ANY SEVERE WEATHER THREAT SATURDAY SHOULD QUICKLY DIMINISH FROM WEST TO EAST SATURDAY NIGHT INTO SUNDAY MORNING AS THE SURFACE LOW CONTINUES TO TRACK EAST ACROSS THE DAKOTAS. STRONG NORTHERLY FLOW WILL BRING MUCH COOLER TEMPERATURES FROM WEST TO EAST SUNDAY...WITH MAINLY IN THE 40S NORTH AND WEST...TO THE LOWER 60S SOUTHEAST. THE STRONG SOUTHERN SHORTWAVE LIFTING THROUGH THE SOUTHERN AND CENTRAL PLAINS SATURDAY MOVES INTO THE NORTHERN PLAINS SUNDAY AND MERGES WITH THE STACKED SYSTEM TRACKING ACROSS THE DAKOTAS. BY SUNDAY AFTERNOON THE THREAT OF SEVERE WEATHER WILL BE TO THE EAST OF THE DAKOTAS...BUT A BAND OF PRECIPITATION IN THE DEFORMATION ZONE IS EXPECTED OVER EASTERN AND POSSIBLY BACK INTO CENTRAL NORTH DAKOTA. THUS SOME PRETTY HEFTY PRECIPITATION AMOUNTS COULD FALL OVER SOUTH CENTRAL INTO NORTHEAST NORTH DAKOTA. WILL NEED TO MONITOR FOR SOME AREAS RECEIVING ENOUGH RAIN TO PRODUCE LOCAL FLOODING ISSUES. ESPECIALLY IF THEY GET HIT WITH PRECIPITATION A FEW TIMES BEFORE THIS. PRECIPITATION FINALLY MOVES OUT OF THE AREA BY SUNDAY EVENING WITH COLD HIGH PRESSURE BUILDING OVER THE AREA INTO EARLY NEXT WEEK. WITH THE SURFACE HIGH MOVING INTO NORTH DAKOTA BY MONDAY MORNING IT LOOKS LIKE A GOOD BET THAT WE WILL NEED A FROST ADVISORY OR MORE LIKELY A FREEZE WARNING...IF CURRENT TEMPERATURE TRENDS HOLD. WE COULD STILL BE DEALING WITH FROST ON TUESDAY MORNING AS WELL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 142 PM CDT THU MAY 14 2015 WIDESPREAD MVFR-IFR CONDITIONS WILL CONTINUE MOST LOCATIONS TODAY. SHRA WILL ALSO CONTINUE TO SPREAD NORTH AND EAST...ENDING AT KJMS 22-00Z. CONDITIONS SHOULD STILL IMPROVE TO VFR OVER PORTIONS OF NORTHWEST NORTH DAKOTA LATER THIS THURSDAY AFTERNOON...WHILE MOST AREAS WILL REMAIN IFR-MVFR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...JV LONG TERM...TWH AVIATION...NH
AREA FORECAST DISCUSSION
NWS AMARILLO TX
417 PM CDT THU MAY 14 2015 .DISCUSSION... WATER VAPOR CHANNEL AND VISIBLE BOTH SHOW EXTENSIVE HIGH LEVEL MOISTURE/CIRRUS STREAMING NORTHEASTWARD ACROSS NEW MEXICO INTO THE SOUTHERN AND CENTRAL PLAINS AHEAD OF A DEEP WEST COAST MID-UPPER LOW. CURRENT OBSERVATIONS SHOW SOUTHERLY SURFACE WINDS AND NEAR NORMAL TEMPERATURES FOR MID MAY ACROSS OUR REGION. THE SHALLOW MOIST LAYER EVIDENT IN 12Z KAMA AND KMAF SOUNDINGS HAS MIXED OUT SOME THIS AFTERNOON WITH A SLIGHT DOWNWARD TREND IN SURFACE DEW POINTS NOTED IN REGIONAL OBSERVATIONS. SLIGHT BACKING TO SURFACE WINDS AND UPSTREAM DEEPER MOISTURE HAS KEPT SURFACE DEW POINTS FROM MIXING OUT FURTHER AND SHORT TERM MODEL FORECAST SOUNDINGS SHOWS GRADUAL DEEPENING OF LOW LEVEL MOISTURE THROUGH THE EVENING. MODEST MLCAPE IS PRESENT ACROSS THE AREA BUT EFFECTIVE BULK SHEAR IS MARGINAL AT BEST FOR STORM ORGANIZATION AND SEVERE WEATHER POTENTIAL. A FEW MARGINALLY SEVERE THUNDERSTORMS ARE STILL POSSIBLE THIS EVENING. VIS SAT/RADAR AND LIGHTNING OBS SHOW ISOLATED/SCATTERED CONVECTIVE DEVELOPMENT SO FAR LIMITED TO SOUTHEAST AND CENTRAL NEW MEXICO AND SOUTHEAST COLORADO. CU FIELD HAS EXPANDED FURTHER EAST BENEATH CIRRUS SHIELD ACROSS EASTERN NEW MEXICO AND AS WEAK SHORTWAVE TROUGH APPROACHES CONVECTION SHOULD EXPAND. CURRENT THINKING IN HOW THIS EVOLVE ALIGNS WELL WITH WRF AND HRRR MODEL PROGNOSTICATIONS AND RESEMBLE OUTPUT FROM THESE REASONABLY WELL. A PATTERN SIMILAR TO WHAT HAS BEEN SEEN RECENTLY AND ONE THAT IS GENERALLY RECOGNIZED FOR BRINGING OUR REGION HIGHER PROBABILITY PRECIPITATION CHANCES CONTINUES THROUGH THE FORECAST PERIOD. AFTER THE DEPARTING WAVE EARLY TOMORROW THE FOCUS SHIFTS TO A PERIOD OF ASCENT WITH ANOTHER APPROACHING SHORTWAVE AND THIS WILL RESULT IN ANOTHER FAIRLY HIGH CONFIDENCE ROUND OF PRECIPITATION FRIDAY EVENING AND OVERNIGHT. MADE MINOR ADJUSTMENTS TO TIMING AND INCREASED BOTH QPF AND PRECIPITATION PROBABILITIES. MODELS ARE NOT TOO DISSIMILAR WITH TIMING OF WHAT COULD BE A FAIRLY EXPANSIVE AREA OF RAIN/THUNDERSTORMS EXITING THE AREA SATURDAY MORNING AND HAVE KEPT PRECIPITATION CHANCES ACROSS THE EASTERN PORTION OF THE AREA THEN. BY AFTERNOON MODEL DIFFERENCES IN POSITION OF THE DRYLINE LEAD TO SOME UNCERTAINTY WITH WHERE CONVECTION WILL REDEVELOP. THE CONSENSUS IS THIS WILL OCCUR NEAR THE TEXAS/OKLAHOMA STATE LINE...OR SLIGHTLY WEST. THUS...RETAINED SLIGHT/LOW CHANCE POPS ACROSS THE EASTERNMOST COUNTIES SATURDAY AFTERNOON. BEHIND THE DRYLINE...DEEP MIXING INTO FAIRLY STRONG MOMENTUM ALOFT COULD RESULT IN A PERIOD OF NEAR ADVISORY CRITERIA WINDS ACROSS PORTIONS OF THE AREA. QUITE WEATHER IS EXPECTED SUNDAY IN BETWEEN TWO WAVES IN A REGION OF MEAN HEIGHT RISES DUE TO LOW AMPLITUDE RIDGING. YET ANOTHER SYSTEM TAKES A SIMILAR TRACK AS THE LAST FEW DOWN THE WEST COAST AND INTO THE DESERT SOUTHWEST BY LATE MONDAY. INCREASING LARGE SCALE ASCENT AND DEEPENING MOISTURE (PWATS RISING TO WELL ABOVE CLIMATOLOGY) SHOULD JUSTIFY FAIRLY HIGH PRECIPITATION PROBABILITIES FROM MONDAY NIGHT THROUGH TUESDAY. THEREAFTER MEDIUM RANGE MODELS DIVERGE BUT THE GENERAL SOUTHWESTERLY FLOW PATTERN WITHOUT ANY ANTECEDENT SIGNIFICANT SOUTHEASTWARD PUSH OF LOW LEVEL MOISTURE NECESSITATES AT LEAST LOW PRECIPITATION PROBABILITIES THROUGH MID WEEK. BRB && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 56 81 57 80 48 / 50 10 60 20 5 BEAVER OK 62 84 59 82 50 / 40 20 60 50 20 BOISE CITY OK 53 79 50 73 47 / 30 10 40 10 5 BORGER TX 60 83 59 79 53 / 50 10 60 20 5 BOYS RANCH TX 55 81 58 78 48 / 50 10 60 10 5 CANYON TX 56 80 57 79 49 / 50 10 60 10 5 CLARENDON TX 59 82 59 80 51 / 50 20 60 30 5 DALHART TX 52 80 54 75 46 / 40 10 50 10 5 GUYMON OK 57 82 56 79 49 / 40 10 50 20 10 HEREFORD TX 54 80 57 77 49 / 40 10 60 10 5 LIPSCOMB TX 62 83 61 81 53 / 50 20 60 50 20 PAMPA TX 59 80 57 78 49 / 50 10 60 30 5 SHAMROCK TX 63 82 63 81 53 / 50 20 60 50 20 WELLINGTON TX 64 84 63 83 54 / 50 20 60 60 20 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 08/17
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 PM CDT THU MAY 14 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 326 PM CDT THU MAY 14 2015 PRIMARY FORECAST CHALLENGES INCLUDE EXITING SHOWERS THIS EVENING... THEN THUNDERSTORM CHANCES AND SEVERE POTENTIAL FRIDAY NIGHT AND AGAIN SUNDAY AFTERNOON AND EVENING. 14.12Z MODEL SUITE IN GOOD OVERALL AGREEMENT AND WILL USE A BLENDED APPROACH. SO FAR TODAY...RAIN HAS BEEN VERY SLOW TO MOVE EAST PAST THE MS RIVER DUE TO DRY SUB-600 HPA LAYER. HOWEVER...AS SHORT-WAVE ALOFT CURRENTLY ACROSS THE EASTERN DAKOTAS INTO SOUTHWEST MN/WESTERN IA LIFTS TO THE NORTHEAST...RAIN SHOWERS WILL MOVE ACROSS THE REST OF THE UPPER MS RIVER VALLEY LATE THIS AFTERNOON AND EVENING. SHOWERS WILL TAPER OFF FROM WEST TO EAST AFTER MIDNIGHT...BUT OVERCAST SKIES OVERNIGHT WILL KEEP TEMPERATURES ELEVATED IN THE 50S. FRIDAY WILL BE WARMER AND DRY AS SHORT-WAVE RIDGING MOVES ACROSS THE REGION. 925 HPA TEMPERATURES RISE TO BETWEEN +14 AND +18 CELSIUS BY 00Z SATURDAY...BUT A MIX OF SUN AND CLOUDS SHOULD RESULT IN AFTERNOON HIGHS RISING INTO THE UPPER 60S ACROSS NORTH CENTRAL WI TO THE MID 70S ACROSS PORTIONS OF NORTHEAST IA AND SOUTHWEST WI. WINDS WILL BE LIGHT AND VARIABLE THROUGH THE DAY. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 326 PM CDT THU MAY 14 2015 FRIDAY EVENING AND OVERNIGHT...SURFACE LOW PRESSURE WILL LIFT FROM THE CENTRAL PLAINS INTO THE DAKOTAS AS A LARGE PACIFIC TROUGH ACROSS THE WESTERN CONUS BEGINS TO PUSH EAST. AN EAST-WEST ORIENTED WARM FRONT WILL MOVE NORTH INTO THE UPPER MS RIVER VALLEY WITH 0 TO 3 KM MUCAPE INCREASING TO BETWEEN 500 AND 1500 J/KG MAINLY SOUTH OF THE I-90 CORRIDOR. AT THE SAME TIME...SHEAR WILL BE WEAK AROUND 20 KTS OR LESS. SOME ELEVATED STRONG TO LOCALLY SEVERE THUNDERSTORMS ARE POSSIBLE...BUT COVERAGE WILL BE LIMITED. PRIMARY THREATS ARE LARGE HAIL AND STRONG WIND. SATURDAY WILL BE WARM AND HUMID WITH INCREASING LOW-LEVEL MOISTURE/ WARM AIR ADVECTION. 925 HPA TEMPERATURES NEARING +20 CELSIUS WILL BRING AFTERNOON HIGHS IN THE UPPER 70S TO LOWER 80S. SURFACE DEW POINT TEMPERATURES WILL ALSO RISE IN THE 60S. AS A RESULT... INSTABILITY WILL RISE ABOVE 2000 J/KG IN PLACES SATURDAY AFTERNOON... BUT FORCING/SHEAR IS VERY WEAK WITH CONTINUED RIDGING ALOFT. SOME SCATTERED SHOWERS AND THUNDERSTORMS COULD DEVELOP...BUT NOT ENOUGH TO WARRANT ANY MORE THAN A 20 TO 30 PERCENT CHANCE. 0 TO 6 KM MUCAPE TO REMAIN AT OR BELOW 500 J/KG SATURDAY NIGHT WITH CONCURRENT DEEP LAYER SHEAR LESS THAN 30 KTS. AGAIN...SOME SCATTERED SHOWERS/ THUNDERSTORMS POSSIBLE OVERNIGHT...BUT MORE SIGNIFICANT CONVECTION WILL BE FARTHER WEST ACROSS THE PLAINS WHICH COULD PROPAGATE IN SOME WAY INTO THE UPPER MS RIVER VALLEY BY SUNDAY MORNING. BEST CHANCE FOR SEVERE CONVECTION ACROSS THE FORECAST AREA WILL BE SUNDAY AFTERNOON AND EVENING AS A STRONG COLD FRONT SWEEPS ACROSS THE UPPER MS RIVER VALLEY. 0 TO 6 KM SHEAR INCREASES TO BETWEEN 40 AND 50 KTS...20 TO 30 KTS OF WHICH ARE IN THE 0 TO 1 KM LAYER. MUCAPE IN THE 0 TO 3 KM LAYER INCREASES TO BETWEEN 1500 AND 2000 J/KG BY 18Z SUNDAY AND WHEN COMBINED WITH STRONG MID-LEVEL MOISTURE TRANSPORT...EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP... SOME OF WHICH MAY BE SEVERE. EARLY SUNDAY MORNING CONVECTION FROM THE PLAINS COMBINED WITH THE SPEED OF THE OVERALL SYSTEM AND POTENTIAL DRY SLOTTING DO INTRODUCE SOME UNCERTAINTY...BUT LARGE HAIL AND STRONG WINDS ARE POSSIBLE WITH ANY STRONGER STORMS THAT DEVELOP. CANNOT RULE OUT AN ISOLATED TORNADO AS WELL GIVEN STRENGTH OF THE SHEAR. WILL BE ABLE TO FINE-TUNE THE DETAILS OVER THE COMING DAYS...BUT FOR NOW...PERSONS WITH OUTDOOR PLANS ON SUNDAY SHOULD PAY CLOSE ATTENTION TO THE LATEST FORECASTS/ STATEMENTS. COLD FRONT TO SWEEP ACROSS THE AREA SUNDAY NIGHT...RESULTING IN A MUCH COOLER AND DRY AIR MASS FOR MUCH OF NEXT WEEK. DAILY HIGHS MONDAY THROUGH THURSDAY UNLIKELY TO BREAK ABOVE THE LOWER 60S WITH OVERNIGHT LOWS FROM THE MID 30S INTO THE 40S. BROAD SURFACE HIGH PRESSURE WILL KEEP CONDITIONS MOSTLY DRY...ALTHOUGH THERE IS A SLIGHT CHANCE FOR SHOWERS WEDNESDAY/THURSDAY AS FLOW ALOFT BECOMES A BIT MORE ZONAL WITH WEAK SHORT-WAVES MOVING THROUGH THE CENTRAL CONUS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1206 PM CDT THU MAY 14 2015 THE LIGHT RAIN HAS BEEN VERY SLOW TO ADVANCE EAST TODAY DUE TO THE DRY AIR IN PLACE OVER WISCONSIN. THE 14.15Z HRRR INDICATES THIS TREND WILL CONTINUE THROUGH THE AFTERNOON WITH THE LIGHT RAIN/SPRINKLES NOT REACHING KLSE UNTIL THE MIDDLE OF THE AFTERNOON. THERE IS ALSO A TREND IN THE HI-RES MESO MODELS THAT THE ACTIVITY COMING UP OUT OF MISSOURI WILL BECOME THE MORE DOMINANT AREA OF RAIN CAUSING A DRY SLOT TO DEVELOP NORTH OF IT AND OVER THE AREA. SOME SUGGESTIONS IN THE REGIONAL RADAR DISPLAY THAT THIS IS INDEED OCCURRING AND THAT IT WILL TAKE THE MORE WIDESPREAD ACTIVITY OVER WESTERN IOWA TO SPREAD IN BEFORE THERE WILL LIKELY BE ANY VISIBILITY RESTRICTIONS OCCURRING. HAVE THUS PUSHED BACK THE TIMING OF MVFR VISIBILITY AT KLSE UNTIL EARLY THIS EVENING BUT STILL SHOW IT BY LATE AFTERNOON AT KRST DUE MORE SO TO SOME LIGHT FOG DEVELOPING AS THE LOW LEVELS CONTINUE TO SATURATE. CEILINGS WILL ALSO CONTINUE TO COME DOWN WITH THIS SATURATION WITH KRST EXPECTED TO GO TO IFR THIS AFTERNOON AND KLSE COMING DOWN TO MVFR THIS EVENING. THE RAIN SHOULD END BY MID TO LATE EVENING WITH BOTH SITES STAYING IFR/MVFR UNTIL FRIDAY MORNING AS THE WINDS START TO PICK UP OUT OF THE NORTHWEST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...ROGERS LONG TERM...ROGERS AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1206 PM CDT THU MAY 14 2015 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 307 AM CDT THU MAY 14 2015 WATER VAPOR IMAGERY THIS MORNING SHOWS A VIGOROUS MID-LEVEL TROUGH LIFTING NORTHEAST ACROSS THE PLAINS WHILE A RIDGE OF HIGH PRESSURE EXTENDED N/S ACROSS OUR AREA. FORCING FROM THIS TROUGH WAS PRODUCING A WIDESPREAD SWATH OF SHOWERS ACROSS EASTERN NEB/WESTERN IA... PUSHING NORTHEAST TOWARD THE AREA. OTHERWISE...PLENTY OF HIGH/MID CLOUD ACROSS THE FORECAST AREA WITH TEMPERATURES AT 2 AM RANGING FROM THE LOWER/MID 40S ACROSS NORTHERN AND CENTRAL WI...TO THE MIDDLE 50S ALONG AND WEST OF THE MISSISSIPPI RIVER. LOOK FOR THAT MID-LEVEL TROUGH TO CONTINUE LIFTING NORTHEAST INTO CENTRAL MN/IA BY LATE THIS AFTERNOON. GOOD AMOUNT OF 850-300MB PV- ADVECTION AND 850MB MOISTURE TRANSPORT WILL CONTINUE TO FUEL SHOWERS AS THEY SLOWLY PUSH INTO THE AREA FROM WEST TO EAST. DRIER LOWER LEVELS ASSOCIATED WITH DEPARTING SURFACE HIGH PRESSURE WILL LIKELY HOLD BULK OF THE SHOWERS WEST OF THE MISSISSIPPI RIVER THROUGH NOON...BEFORE THEY OVERSPREAD THE REST OF THE AREA THROUGH THE AFTERNOON HOURS. DUE TO THE CLOUDS AND INCOMING SHOWERS... TEMPERATURES WILL SUFFER SOMEWHAT...RANGING FROM THE UPPER 50S TO THE LOWER 60S. SHOWERS WILL CONTINUE THROUGH MIDNIGHT ACROSS MOST OF THE AREA...THEN START A SLOW DIMINISHING TREND FROM WEST TO EAST AFTER MIDNIGHT AS THE TROUGH DEPARTS EAST AND RIDGING BUILDS IN FROM MN/IA. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE UPPER 40S TO THE MIDDLE 50S. APPEARS RAINFALL FROM THIS SYSTEM WILL BE SOMEWHERE IN THE 1/2 TO 3/4 INCH RANGE. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 307 AM CDT THU MAY 14 2015 A FEW VERY LIGHT SHOWERS MAY BE ONGOING EARLY FRIDAY MORNING EAST OF THE MISSISSIPPI RIVER EARLY IN THE MORNING AS THE TROUGH DEPART... BUT SKIES ARE EXPECTED TO BECOME PARTLY CLOUDY BY AFTERNOON AS A RIDGE OF HIGH PRESSURE WORKS INTO THE AREA. PLAN ON HIGHS IN THE UPPER 60S THE THE LOWER 70S. FOCUS THEN SHIFTS TO THE POTENTIAL FOR SOME STRONG TO SEVERE STORMS THROUGH THE WEEKEND. MODELS HAVE BEEN CONSISTENT IN PUSHING A WARM FRONT NORTHWARD INTO/ACROSS THE AREA FRIDAY NIGHT THROUGH SATURDAY. INCREASING 850MB MOISTURE TRANSPORT INTO/OVER THE WARM FRONT IS EXPECTED TO FUEL SCATTERED THUNDERSTORM ACTIVITY. NAM SHOWING MUCAPE OF 1500-2000J/KG LATE FRIDAY NIGHT INTO SATURDAY MORNING WITH 0-3KM SHEAR OF 20-25KT. SO...LOOKS LIKE WE HAVE THE POTENTIAL TO GET A FEW STRONGER/MAINLY PULSE TYPE THUNDERSTORMS AHEAD OF THE FRONT AS IT PUSHES NORTH INTO/THROUGH THE AREA. THE FRONT LOOKS LIKE IT WILL PUSH NORTH OF THE AREA BY LATE MORNING...LEAVING OUR AREA IN A WEAKLY CAPPED ENVIRONMENT WITH WARM/HUMID AIRMASS IN PLACE. MAY HAVE TO WATCH CLOSELY FOR SEVERE THUNDERSTORM POTENTIAL DURING THE AFTERNOON WHERE NAM IS PRODUCING MUCAPE IN THE 3000-5000J/KG RANGE ALONG WITH 0-3KM BULK SHEAR OF 25-30KT. NAM INSTABILITY MAY BE A BIT OVERDONE BASED ON 70 DEGREE OUTPUT DEWPOINTS...BUT LOWER/MID 60S DEW POINTS LOOK REALISTIC WHICH WOULD YIELD CAPE IN THE 2000-4000J/KG. LOOKS LIKE HIGHEST SEVERE POTENTIAL WOULD BE WESTERN PORTIONS OF THE AREA WHERE STEEPER MID-LEVEL LAPSE RATES/HIGHER-END OF THE BULK SHEAR WILL EXIST. OTHERWISE...LOOK FOR HIGHS IN THE UPPER 70S TO THE LOWER 80S. SHOWERS AND THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE FROM WEST TO EAST SATURDAY NIGHT THROUGH SUNDAY AS FAIRLY STRONG SURFACE CYCLOGENESIS TAKES PLACE OVER THE NORTHERN PLAINS...FUELING STRONGER MOISTURE TRANSPORT/LIFT INTO THE AREA. CANNOT RULE OUT A FEW STRONG TO SEVERE STORMS OVER WESTERN PORTIONS OF THE AREA SATURDAY NIGHT IN DEEP SHEAR/HIGHER CAPE ENVIRONMENT. STRONG TO SEVERE STORM THREAT CONTINUES SUNDAY AS A COLD FRONT PUSHES INTO THE AREA. EXTENT OF SEVERE THREAT WILL BE DEPENDENT OF HOW MUCH THE ATMOSPHERE CAN RECOVER FROM ONGOING CONVECTION AND TIMING OF THE FRONT. WILL CONTINUE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES SUNDAY ARE EXPECTED TO TOP OFF IN THE MIDDLE/UPPER 70S. AFTER THIS...BEGINNING OF THE NEW WORK WEEK LOOKS COOLER/DRIER BEHIND THE DEPARTING LOW/COLD FRONT. PLAN ON HIGHS MONDAY AND TUESDAY IN THE UPPER 50S TO THE LOWER 60S. SHOWER/THUNDERSTORM CHANCES SPREAD INTO THE AREA AGAIN BY WEDNESDAY IN WARM AIR ADVECTION AHEAD OF A TROUGH PUSHING OUT OF THE PLAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1206 PM CDT THU MAY 14 2015 THE LIGHT RAIN HAS BEEN VERY SLOW TO ADVANCE EAST TODAY DUE TO THE DRY AIR IN PLACE OVER WISCONSIN. THE 14.15Z HRRR INDICATES THIS TREND WILL CONTINUE THROUGH THE AFTERNOON WITH THE LIGHT RAIN/SPRINKLES NOT REACHING KLSE UNTIL THE MIDDLE OF THE AFTERNOON. THERE IS ALSO A TREND IN THE HI-RES MESO MODELS THAT THE ACTIVITY COMING UP OUT OF MISSOURI WILL BECOME THE MORE DOMINANT AREA OF RAIN CAUSING A DRY SLOT TO DEVELOP NORTH OF IT AND OVER THE AREA. SOME SUGGESTIONS IN THE REGIONAL RADAR DISPLAY THAT THIS IS INDEED OCCURRING AND THAT IT WILL TAKE THE MORE WIDESPREAD ACTIVITY OVER WESTERN IOWA TO SPREAD IN BEFORE THERE WILL LIKELY BE ANY VISIBILITY RESTRICTIONS OCCURRING. HAVE THUS PUSHED BACK THE TIMING OF MVFR VISIBILITY AT KLSE UNTIL EARLY THIS EVENING BUT STILL SHOW IT BY LATE AFTERNOON AT KRST DUE MORE SO TO SOME LIGHT FOG DEVELOPING AS THE LOW LEVELS CONTINUE TO SATURATE. CEILINGS WILL ALSO CONTINUE TO COME DOWN WITH THIS SATURATION WITH KRST EXPECTED TO GO TO IFR THIS AFTERNOON AND KLSE COMING DOWN TO MVFR THIS EVENING. THE RAIN SHOULD END BY MID TO LATE EVENING WITH BOTH SITES STAYING IFR/MVFR UNTIL FRIDAY MORNING AS THE WINDS START TO PICK UP OUT OF THE NORTHWEST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...04
AREA FORECAST DISCUSSION...CORRECTED AVIATION
NWS CHEYENNE WY
1204 PM MDT THU MAY 14 2015 .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 300 AM MDT THU MAY 14 2015 FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LOW LEVEL MOISTURE IS NOT ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z. UPPER LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE EJECTS NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER CALIFORNIA. WITH GOOD MID LEVEL ISENTROPIC ASCENT AND SOME ELEVATED CAPE...THIS IS ACTUALLY A SITUATION WHERE SHOWER AND TSTM COVERAGE COULD BE GREATER INTO THE NIGHT...ESPECIALLY OVER THE NORTHEASTERN HALF OF THE CWA. THUS...KEPT THE 30-40 POPS GOING THROUGH EARLY FRI MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE TO ADVECT HIGHER DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT. THE MOST IMPACTING EVENT IN THE SHORT TERM IS STILL LOOKING LIKE THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI. OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS THIS WOULD PUSH THE SEVERE THREAT INTO SOUTHEAST WY. WHILE LARGE HAIL WOULD LIKELY BE THE PRIMARY THREAT...THE LOW LEVEL SHEAR PARAMETERS DO SHOW THE POTENTIAL FOR SOME WEAK TORNADOES ESPECIALLY ALONG AND JUST NORTH OF THE WARM FRONT WHERE WINDS WILL BE BACKED THE MOST. NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3 KM HELICITY OF 250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2 SPC OUTLOOK HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A SLIGHT RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO NORTH PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE SFC LOW AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE A BIT LESS LOW LEVEL MOISTURE AND INSTABILITY TO WORK WITH ON SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A COLD FRONT PUSHING ACROSS THE REGION. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 300 AM MDT THU MAY 14 2015 AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG /NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LOW LEVEL UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LOW LEVEL FORCING BENEATH INCREASINGLY DIFFLUENT FLOW ALOFT AND A COUPLED H25 JET. THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM ADVECTION IN LOW LEVEL EASTERLY/UPSLOPE FLOW MAKES THIS QUESTIONABLE AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO SEE PCPN CHANGE TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST FOR HIGHER ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST VIRTUALLY EVERY DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES EACH AFTN THROUGH WED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1159 AM MDT THU MAY 14 2015 VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS THIS AFTERNOON AND EVENING. WIDELY SCATTERED SHOWERS/TSTORMS WILL DEVELOP AFTER 20Z ACROSS SOUTHEAST WY...WITH MORE ISOLATED OVER FAR WESTERN NE AFTER 00Z. CONVECTION MAY BE ACCOMPANIED BY GUSTY AND ERRATIC WINDS AND LOCALIZED MVFR CIGS/VSBYS. MVFR-IFR CIGS AND MVFR VSBYS SHOULD BECOME MORE WIDESPREAD OVER WESTERN NE AND FAR SOUTHEAST WY AFTER 09Z. && .FIRE WEATHER... ISSUED AT 300 AM MDT THU MAY 14 2015 NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO 25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL GREEN UP AFTER THE RECENT WET PERIOD. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...CLH AVIATION...MJ FIRE WEATHER...ZF