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


AREA FORECAST DISCUSSION
NWS PUEBLO CO
236 PM MDT SUN MAY 3 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 234 PM MDT SUN MAY 3 2015 SHOWERS AND STORMS THAT HAVE DEVELOPED THIS AFTERNOON HAVE GENERALLY BE FAIRLY SLOW MOVING AND SHORT LIVED. ISOLATED TO SCATTERED SHOWERS AND TSTMS OVR THE AREA WL CONTINUE INTO THE EVENING HOURS...AND DECREASING TOWARD MIDNIGHT. A COLD FRONT WL MOVE SOUTH INTO THE SOUTHEAST PLAINS THIS EVENING...WITH THE NAM SHOWING IT REACHING THE SRN CO BORDER EARLY MON MORNING. BEHIND THE FRONT...SFC DEW POINTS INCREASE INTO THE 40S...AND LOW STRATUS IS FORECAST TO DEVELOP OVR NORTHERN EL PASO COUNTY BY MIDNIGHT AND THEN SPREADING SOUTHWARD OVERNIGHT. THE HRRR...NSSL WRF AND NAM CONTINUE TO SHOW PCPN BEHIND THE FRONT OVR EL PASO AND TELLER COUNTIES DURING THE LATE NIGHT HOURS...WITH MUCH OF THE REST OF THE FORECAST AREA BEING DRY. THE HRRR SPREADS PCPN SOUTHWARD INTO PUEBLO AND FREMONT COUNTIES AS WELL. ON MONDAY AN UPR LOW BECOME CENTERED OVR THE CA AND AZ BORDER WITH SOUTHERLY FLOW ALOFT OVR THE FORECAST AREA AHEAD OF THIS SYSTEM...DRAWING MSTR NORTHWARD. WITH MOIST LOW TO MID LEVEL SOUTHEASTERLY WINDS...KEEPING AFTERNOON SFC DEW POINTS ACRS THE SERN PLAINS IN THE MID40S TO LOWER 50S. MOST OF THE LOW STRATUS IS EXPECTED TO DISSIPATE BEFORE AFTERNOON. THE NAM SHOWS SHOWERS/TSTMS DEVELOPING IN THE MID MORNING HOURS OVR THE MTNS...ESPECIALLY ALONG THE CONTDVD...WHERE A SHORTWAVE TROF IS EXPECTED TO MOVE NORTHWARD THRU THE AREA. PCPN WL INCREASE ACRS THE MTNS BY MIDDAY AND WL SPREAD TO THE ADJACENT LOWER ELEVATIONS...AND THEN THROUGH THE AFTERNOON WL BECOME WIDESPREAD ACRS MOST OF THE FORECAST AREA. THERE WL BE THE POTENTIAL FOR LOCALIZED HEAVY RAIN. ALSO...PORTIONS OF THE SERN PLAINS COULD SEE ONE OR TWO MARGINALLY SEVERE STORMS IN THE AFTERNOON. HIGH TEMPS ON MON WILL BE COOLER THAN TODAY AND SHOULD GENERALLY BE JUST A LITTLE BELOW NORMAL. HIGH TEMPS IN THE SAN LUIS VALLEY SHOULD BE CLOSE TO NORMAL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 234 PM MDT SUN MAY 3 2015 ...STORMY WEATHER THROUGH TUESDAY... MONDAY NIGHT...WILL SEE SEVERAL ONGOING ROUNDS OF PRECIP AND STORMS OVER THE AREA. THE STRONGEST OF THESE WILL LIKELY BE OVER THE ERN PLAINS...GENERALLY E OF KLHX...AND ANOTHER AREA OVER THE PALMER DVD. GIVEN THE ABUNDANT LLVL MOISTURE AND INCREASED SHEAR DUE TO BACKED LLVL FLOW...CANNOT RULE OUT A STRONG TO SVR STORM OR TWO ESPECIALLY IN THESE FAVORED AREAS. COULD SEE A BRIEF LULL IN THE PRECIP MON EVE BEFORE PRECIP COVERAGE INCREASES LATER MON NIGHT...IN BANDS OF CONVECTION ROTATING UP FROM THE SOUTH. WILL MAINTAIN ISOLD OR SLIGHT CHANCE OF TS OVERNIGHT ALONG WITH MORE WIDESPREAD LIKELY POPS ACROSS THE MTS AND PLAINS. ON TUE...THE UPPER LOW WILL MOVE INTO THE FOUR CORNERS REGION...THEN TRACK TO THE NE DURING THE DAY. TEMPS WILL BE COOLER...IN THE 60S FOR THE PLAINS...DUE TO WIDESPREAD CLOUDS AND PRECIP. IT LOOKS LIKE MUCH OF THE BEST PRECIP COVERAGE WILL BE TUE MORNING...ALTHOUGH EVEN IF THERE ARE ANY BREAKS IN THE SHOWERS AND STORMS...THEY SHOULD PICK UP AGAIN BY TUE AFTERNOON. SNOW LEVELS MON-TUE WILL BE PRETTY HIGH...BUT GIVEN THE AMOUNT OF QPF...COULD SEE SOME LOCAL SIGNIFICANT ACCUMS IN THE MTS OF SIX INCHES OR MORE...ESPECIALLY ABOVE 12000 FEET. SO...RECREATIONISTS SHOULD BE AWARE OF WINTER CONDITIONS FOR THE HIGH PEAKS. GIVEN ALL THE PRECIP...THE BL SHOULD BE PRETTY STABILIZED BY TUE SO SURFACE BASED CONVECTION LOOKS UNLIKELY. BUT...A STRONG STORM OR TWO CANNOT BE RULED OUT OVER THE AREA AS THE UPPER LOW MOVES THROUGH NRN CO. BY WED...SHOULD SEE THINGS WINDING DOWN AS THE FIRST UPPER LOW MOVES OFF INTO THE DAKOTAS AND NE. WILL STILL SEE SOME WRAP AROUND PRECIP OVER THE DVD AND NRN PORTIONS OF THE CWA. TEMPS SHOULD REBOUND NICELY BACK INTO THE 70S OVER THE PLAINS. THE NEXT SYSTEM WILL DROP SWD FROM THE PACNW ON WED...THEN CUTOFF OVER CA THU-SAT...AND SLOWLY MOVE TO THE NE OVER THE WEEKEND. GLOBAL MODELS ARE STILL IN GOOD AGREEMENT THAT THIS SYSTEM WILL TRACK TO OUR NORTH NEXT WEEKEND...ALTHOUGH LATEST RUNS HINT THAT THE TRACK MAY BE A BIT FARTHER SOUTH. STILL LOOKS LIKE MOST OF SE CO WILL BE STUCK IN THE DRY SW FLOW TO THE SOUTH OF THE LOW...BUT GIVEN THE UNCERTAINTIES WILL MAINTAIN POPS OVER THE AREA...ESPECIALLY FOR THE MTS. TEMPS WILL BE CONSIDERABLY LOWER WITH THIS SYSTEM...AS H7 TEMPS ARE MINUS THREE OR LOWER...SO SOME MTN SNOWS SEEM LIKE A GOOD BET. ROSE && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 234 PM MDT SUN MAY 3 2015 VFR CONDITIONS ARE EXPECTED AT THE TAF SITES UNTIL LATE TONIGHT. ISOLATED TO SCATTERED TSTMS MAY MOVE INTO THE VCNTY OF THE TAF SITES THIS EVENING WITH ERRATIC GUSTY WINDS BEING THE MAIN THREAT. LATE TONIGHT IT LOOKS LIKE AT KCOS AN MVFR OR IFR CIG WL DEVELOP AS LOW STRATUS DEVELOPS BEHIND A COLD FRONT. ISOLD SHOWERS AND TSTMS MAY ALSO CONTINUE AT KCOS INTO THE LATE NIGHT HOURS. KPUB COULD ALSO SEE SOME PCPN LATE TONIGHT AND MAYBE EVEN SEE SOME LOW STRATUS MOVE INTO THE VCNTY...HOWEVER CHANCES OF THIS OCCURRING ARE A BIT UNCERTAIN AT THIS TIME. THE LOW STRATUS IS FORECAST TO DISSIPATE BY MID TO LATE MORNING WITH VFR CONDITIONS EXPECTED AT THE TAF SITES ON MONDAY. SHOWERS AND TSTMS ARE ONCE AGAIN A POSSIBILITY AT THE TAF SITES...MAINLY IN THE AFTERNOON HOURS. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...ROSE AVIATION...28
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1255 PM EDT SUN MAY 3 2015 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE OVER THE EASTERN UNITED STATES TODAY WILL GRADUALLY MOVE OFFSHORE ON MONDAY. A COLD FRONT IS FORECAST TO WEAKEN AS IT DROPS SOUTHWARD ACROSS THE AREA TUESDAY THROUGH EARLY WEDNESDAY. HIGH PRESSURE RETURNS LATE IN THE WEEK. THE HIGH WILL EVENTUALLY SHIFT OFF THE EAST COAST NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12Z UA ANLYS VERY DRY AT 850MB AND 925MB LEVELS IN THE EASTERN CONUS. HAVE TO CLIMB TO 700MB TO FIND SOME APPRECIABLE MOISTURE. 925MB TEMPS IN THE GREAT LAKES AROUND 18C WITH 850MB TEMPS NORTH OF 10C. THAT WILL BE OUR AIR MASS TOMORROW. WE ARE PLANNING NO BIG CHANGES WITH THE NEXT UPDATE. 12Z MODEL DATA EXCEPT FOR THE GFS AND ALL OTHER MESOSCALE MODELS KEEP US DRY INTO THIS EVENING. THE GFS HAS HAD THE HIGHEST .01" ISOHYET WET BIAS (AMONG IT, SREF, NAM AND EC) WI 24HR DURING THE PAST MONTH AND THE LOWEST QPF SKILL SCORE OF ALL THOSE MODELS IN THE NORTHEAST WITH QPF OF LESS THAN .75". THERMALLY IT IS SIMILAR TO YESTERDAY WITH LOCATIONS NW RISING FASTER THAN FORECAST WITH SOME LOCALES LAGGING NEAR THE COAST. OVERALL WE ARE WITHIN ABOUT 3F OF EXPECTATIONS, SO JUST SLIGHT ADJUSTMENTS WILL BE MADE. HIGH PRES WILL BE OVER THE SERN CONUS TODAY. SWLY FLOW WILL INCREASE AND TEMPS WILL WARM IN RESPONSE. HIGHS ARE EXPECTED TO BE IN THE MID TO UPPER 70S, WITH SOME LOCATIONS MAKING A RUN AT 80 DEGREES. NO PRECIP IS ANTICIPATED. THERE WILL BE SOME SCT CLOUDS ON AN OTHERWISE BEAUTIFUL DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... THE AREA OF HIGH PRES WILL MOVE EWD AND OFF THE CST AND A GENLY CLEAR SKY IS IN STORE WITH LIGHT WIND. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE CENTER OF SURFACE HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND MORE HUMID AIR UP THE EASTERN SEABOARD. MONDAY WILL CONTEND WITH APRIL 18TH FOR THE WARMEST DAY SO FAR THIS YEAR WITH HIGHS 80-85 DEGREES (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). CONDITIONS ACROSS THE FORECAST AREA WILL BE DRY THROUGH MONDAY NIGHT OWING TO STRONG SUBSIDENCE PRESENT BENEATH THE H8 RIDGE. A COLD FRONT WILL MOVE SLOWLY SOUTHWARD THROUGH THE AREA TUESDAY AFTERNOON AND NIGHT. CLOUDS OVERSPREADING NORTHEAST PA AND NORTHWEST NJ WILL RESULT IN SLIGHTLY COOLER HIGHS IN THE 70S ON TUESDAY. FARTHER SOUTH IN THE WARM SECTOR, HIGHS TUESDAY HAVE THE POTENTIAL TO BE CLOSE TO MONDAY`S FROM ABOUT PHILLY SOUTHWARD IF THE FRONT AND ITS ASSOCIATED CLOUD COVER HANGS BACK TO THE NORTH. MOISTURE WILL POOL ALONG THE FRONT AS NOTED BY PWATS INCREASING TO NEAR 1.5 INCHES AND SURFACE DEWPOINTS TO NEAR 60F BY THE AFTERNOON. BUFKIT SOUNDINGS FROM THE 00Z GFS AND 21Z SREF SHOW MODEST INSTABILITY (ML CAPE AROUND 500 J/KG) WHILE THE 00Z NAM DEPICTS A CONSIDERABLY MORE UNSTABLE ENVIRONMENT (ML CAPE AOA 1000 J/KG). WENT MORE CONSERVATIVE WITH FORECAST COVERAGE OF THUNDERSTORMS DUE TO THE PRESENCE OF WEAK SHEAR AND LIMITED FORCING IN ADDITION TO THE QUESTIONABLE INSTABILITY. A GENERAL WEAKENING TREND IS EXPECTED WITH THE CONVECTION AFTER SUNSET, ALTHOUGH SHOWERS MAY LINGER INTO THE OVERNIGHT AS SLIGHTLY BETTER LIFT ASSOCIATED WITH AN UPPER SHORTWAVE TROUGH ARRIVES LATE. THE FRONT MAY EITHER CONTINUE TO SAG SOUTHWARD SLOWLY OR EVEN STALL OVER THE DELMARVA WEDNESDAY MORNING. LIFT ASSOCIATED WITH THE FRONT ITSELF SHOULD WEAKEN AS THE BOUNDARY IS EXPECTED TO BECOME INCREASINGLY DIFFUSE. CONSEQUENTIALLY, COVERAGE OF SHOWERS EXPECTED TO BE RELATIVELY LOW ON WEDNESDAY. THUNDERSTORM CHANCES CONFINED TO THE LOWER DELMARVA, WHERE THESE LOCATIONS HAVE THE BEST CHANCE OF RESIDING IN THE WARM SECTOR TO THE SOUTH OF THE BOUNDARY. THE CAA BEHIND THE FRONT IS NOT SIGNIFICANT, SO THE TREND OF ABOVE NORMAL TEMPS SHOULD CONTINUE INTO WEDNESDAY. HOWEVER, WE WILL HAVE TO WATCH FOR THE POSSIBILITY OF ONSHORE FLOW TO DEVELOP. THIS MAY PREVENT TEMPS FROM REACHING 70F IN THE COASTAL PLAIN, ESPECIALLY THE EASTERLY WIND BECOMES ENHANCED BY A SEABREEZE. EXPANSIVE HIGH PRESSURE OVER THE EASTERN SEABOARD WILL PROVIDE A MAINLY DRY PATTERN THURSDAY THROUGH SATURDAY. THE HUMIDITY IS FORECAST TO INCREASE A BIT FRIDAY AND SATURDAY AS SOUTHERLY RETURN FLOW DEVELOPS WITH THE SURFACE HIGH MOVING OFFSHORE. CANNOT RULE OUT THE POSSIBILITY OF A A SHOWER DEVELOPING DURING THE AFTERNOON HOURS FRIDAY AND SATURDAY BUT THE SUBSIDENCE INVERSION UNDERNEATH THE RIDGE SHOULD MINIMIZE THE CONVECTIVE POTENTIAL. ABOVE NORMAL TEMPS WILL PERSIST WITH HIGHS IN THE 70S TO NEAR 80F EACH DAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 18Z TAFS WILL BE VFR. THIS AFTERNOON...VERY HIGH BASED (7K) FEW TO SCATTERED CUMULUS CLOUDS EXPECTED. LIGHT WEST WINDS (AROUND 5 KNOTS) ALL TERMINALS PRECEDING ANY SEA/BAY BREEZE FRONTAL PASSAGE. SEA/BAY BREEZE FRONT SHOULD BE FROM LEWES THROUGH CAPE MAY COUNTY, JUST WEST OF KACY AND KBLM AT START OF TAF PERIOD. BY 21Z SHOULD BE WEST OF KGED AND KDOV AND THRU KMIV, MOST OF ATLC COUNTY, SERN BURLINGTON COUNTY AND OCEAN AND MONMOUTH COUNTIES. FROM THERE THE PROGRESS IS EXPECTED TO BE SLOWER PASSING KILG BY 22Z AND REACHING THE DELAWARE RIVER TERMINALS AROUND 00Z. WINDS BEHIND THE FRONT SHOULD AVERAGE SOUTH-SOUTHEAST AT AROUND 10 KNOTS. TONIGHT...CLEAR SKIES AND WINDS BECOMING LIGHT AND VARIABLE. AIR MASS AGAIN IS QUITE CLEAN AND WE ARE NOT ANTICIPATING ANY FOG AT THE TERMINALS. MONDAY...A SOUTHWEST WIND WILL DEVELOP IN THE MORNING AND SHOULD AVERAGE CLOSE TO 10 KNOTS. SOME GUSTINESS IS LIKELY AS THE DAY PROGRESS, MORE LIKELY IN THE AFTERNOON. THE PREDICTED MOISTURE AT THE CUMULUS LEVEL IS SLIGHTLY MORE THAN TODAY, SO MAYBE A FEW MORE HIGH BASED (LOOKS AROUND 7K AGAIN) CUMULUS CLOUDS AGAIN. OUTLOOK... MONDAY AFTERNOON AND MONDAY NIGHT...VFR. SWLY MAY GUST TO 20 KT LATE IN THE DAY. TUESDAY AND TUESDAY NIGHT...PREDOMINATELY VFR. SCT SHRA AND ISO TSRA DURING THE AFTERNOON AND NIGHT COULD YIELD LOCAL MVFR/IFR CONDITIONS. WEDNESDAY...SHRA MAY LINGER INTO WEDNESDAY BUT MOST OF THE TERMINALS SHOULD DRY OUT. SOME MODEL SOLUTIONS ARE INDICATING EASTERLY WINDS TO DEVELOP. WILL HAVE TO WATCH FOR LOW CLOUDS AND MVFR CIGS TO ACCOMPANY MARINE LAYER. WEDNESDAY NIGHT AND THURSDAY...VFR. && .MARINE... SEAS AS OF 10 AM HAVE DROPPED TO 4.6 FEET AT BOTH BUOY9 AND 65. IN ADDITION, THE PERIOD HAS INCREASED TO AROUND 10 SECONDS. WITH THE DOWNWARD TREND UNDERWAY, WE WILL FINALLY PUT THIS SMALL CRAFT ADVISORY IN THE BOOKS AND HAVE NO FURTHER EXTENSION. WE ADJUSTED THE WINDS IN DELAWARE BAY THIS AFTERNOON AND EVE BASED ON HRRR AND ARW MODELS AS THEY HANDLED THE UP THE BAY BREEZE WELL YESTERDAY. NO ADDITIONAL FLAGS ARE EXPECTED DURG THE REMAINDER OF THE NR AND SHORT TERM PDS. OUTLOOK... MONDAY THROUGH THURSDAY...WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA. THE STRONGEST WINDS ARE EXPECTED MONDAY AND TUESDAY AS HIGH PRESSURE MOVES OFFSHORE AND A S-SW FLOW AROUND 15-20 KT ENSUES. && .FIRE WEATHER... RELATIVE HUMIDITY VALUES NEAR 30 PERCENT, ALONG WITH OCCASIONAL WIND GUSTS TO NEAR 20 MPH MAY ENHANCE THE FIRE WEATHER RISK LATE IN THE DAY ON MONDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...GIGI/KLEIN/NIERENBERG MARINE...GIGI/KLEIN/NIERENBERG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1152 AM EDT SUN MAY 3 2015 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE OVER THE EASTERN UNITED STATES TODAY WILL GRADUALLY MOVE OFFSHORE ON MONDAY. A COLD FRONT IS FORECAST TO WEAKEN AS IT DROPS SOUTHWARD ACROSS THE AREA TUESDAY THROUGH EARLY WEDNESDAY. HIGH PRESSURE RETURNS LATE IN THE WEEK. THE HIGH WILL EVENTUALLY SHIFT OFF THE EAST COAST NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12Z UA ANLYS VERY DRY AT 850MB AND 925MB LEVELS IN THE EASTERN CONUS. HAVE TO CLIMB TO 700MB TO FIND SOME APPRECIABLE MOISTURE. 925MB TEMPS IN THE GREAT LAKES AROUND 18C WITH 850MB TEMPS NORTH OF 10C. THAT WILL BE OUR AIR MASS TOMORROW. WE ARE PLANNING NO BIG CHANGES WITH THE NEXT UPDATE. 12Z MODEL DATA EXCEPT FOR THE GFS AND ALL OTHER MESOSCALE MODELS KEEP US DRY INTO THIS EVENING. THE GFS HAS HAD THE HIGHEST .01" ISOHYET WET BIAS (AMONG IT, SREF, NAM AND EC) WI 24HR DURING THE PAST MONTH AND THE LOWEST QPF SKILL SCORE OF ALL THOSE MODELS IN THE NORTHEAST WITH QPF OF LESS THAN .75". THERMALLY IT IS SIMILAR TO YESTERDAY WITH LOCATIONS NW RISING FASTER THAN FORECAST WITH SOME LOCALES LAGGING NEAR THE COAST. OVERALL WE ARE WITHIN ABOUT 3F OF EXPECTATIONS, SO JUST SLIGHT ADJUSTMENTS WILL BE MADE. HIGH PRES WILL BE OVER THE SERN CONUS TODAY. SWLY FLOW WILL INCREASE AND TEMPS WILL WARM IN RESPONSE. HIGHS ARE EXPECTED TO BE IN THE MID TO UPPER 70S, WITH SOME LOCATIONS MAKING A RUN AT 80 DEGREES. NO PRECIP IS ANTICIPATED. THERE WILL BE SOME SCT CLOUDS ON AN OTHERWISE BEAUTIFUL DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... THE AREA OF HIGH PRES WILL MOVE EWD AND OFF THE CST AND A GENLY CLEAR SKY IS IN STORE WITH LIGHT WIND. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE CENTER OF SURFACE HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND MORE HUMID AIR UP THE EASTERN SEABOARD. MONDAY WILL CONTEND WITH APRIL 18TH FOR THE WARMEST DAY SO FAR THIS YEAR WITH HIGHS 80-85 DEGREES (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). CONDITIONS ACROSS THE FORECAST AREA WILL BE DRY THROUGH MONDAY NIGHT OWING TO STRONG SUBSIDENCE PRESENT BENEATH THE H8 RIDGE. A COLD FRONT WILL MOVE SLOWLY SOUTHWARD THROUGH THE AREA TUESDAY AFTERNOON AND NIGHT. CLOUDS OVERSPREADING NORTHEAST PA AND NORTHWEST NJ WILL RESULT IN SLIGHTLY COOLER HIGHS IN THE 70S ON TUESDAY. FARTHER SOUTH IN THE WARM SECTOR, HIGHS TUESDAY HAVE THE POTENTIAL TO BE CLOSE TO MONDAY`S FROM ABOUT PHILLY SOUTHWARD IF THE FRONT AND ITS ASSOCIATED CLOUD COVER HANGS BACK TO THE NORTH. MOISTURE WILL POOL ALONG THE FRONT AS NOTED BY PWATS INCREASING TO NEAR 1.5 INCHES AND SURFACE DEWPOINTS TO NEAR 60F BY THE AFTERNOON. BUFKIT SOUNDINGS FROM THE 00Z GFS AND 21Z SREF SHOW MODEST INSTABILITY (ML CAPE AROUND 500 J/KG) WHILE THE 00Z NAM DEPICTS A CONSIDERABLY MORE UNSTABLE ENVIRONMENT (ML CAPE AOA 1000 J/KG). WENT MORE CONSERVATIVE WITH FORECAST COVERAGE OF THUNDERSTORMS DUE TO THE PRESENCE OF WEAK SHEAR AND LIMITED FORCING IN ADDITION TO THE QUESTIONABLE INSTABILITY. A GENERAL WEAKENING TREND IS EXPECTED WITH THE CONVECTION AFTER SUNSET, ALTHOUGH SHOWERS MAY LINGER INTO THE OVERNIGHT AS SLIGHTLY BETTER LIFT ASSOCIATED WITH AN UPPER SHORTWAVE TROUGH ARRIVES LATE. THE FRONT MAY EITHER CONTINUE TO SAG SOUTHWARD SLOWLY OR EVEN STALL OVER THE DELMARVA WEDNESDAY MORNING. LIFT ASSOCIATED WITH THE FRONT ITSELF SHOULD WEAKEN AS THE BOUNDARY IS EXPECTED TO BECOME INCREASINGLY DIFFUSE. CONSEQUENTIALLY, COVERAGE OF SHOWERS EXPECTED TO BE RELATIVELY LOW ON WEDNESDAY. THUNDERSTORM CHANCES CONFINED TO THE LOWER DELMARVA, WHERE THESE LOCATIONS HAVE THE BEST CHANCE OF RESIDING IN THE WARM SECTOR TO THE SOUTH OF THE BOUNDARY. THE CAA BEHIND THE FRONT IS NOT SIGNIFICANT, SO THE TREND OF ABOVE NORMAL TEMPS SHOULD CONTINUE INTO WEDNESDAY. HOWEVER, WE WILL HAVE TO WATCH FOR THE POSSIBILITY OF ONSHORE FLOW TO DEVELOP. THIS MAY PREVENT TEMPS FROM REACHING 70F IN THE COASTAL PLAIN, ESPECIALLY THE EASTERLY WIND BECOMES ENHANCED BY A SEABREEZE. EXPANSIVE HIGH PRESSURE OVER THE EASTERN SEABOARD WILL PROVIDE A MAINLY DRY PATTERN THURSDAY THROUGH SATURDAY. THE HUMIDITY IS FORECAST TO INCREASE A BIT FRIDAY AND SATURDAY AS SOUTHERLY RETURN FLOW DEVELOPS WITH THE SURFACE HIGH MOVING OFFSHORE. CANNOT RULE OUT THE POSSIBILITY OF A A SHOWER DEVELOPING DURING THE AFTERNOON HOURS FRIDAY AND SATURDAY BUT THE SUBSIDENCE INVERSION UNDERNEATH THE RIDGE SHOULD MINIMIZE THE CONVECTIVE POTENTIAL. ABOVE NORMAL TEMPS WILL PERSIST WITH HIGHS IN THE 70S TO NEAR 80F EACH DAY. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDS WILL PREVAIL THRU THE TAF PD WITH HIGH PRES TO THE SE TODAY MOVG OFFSHORE TONIGHT. THE FLOW WILL BECOME SWLY BY AFTN BUT WILL BE LESS THAN 10 KTS. ONLY SCT CLOUDS ARE ANTICIPATED. WITH LIGHT FLOW, STILL EXPECTING ANOTHER SEA BREEZE AT KACY AND KMIV. AT THESE LOCATIONS, WIND COULD REACH 10 KT OR SO. OUTLOOK... MONDAY AND MONDAY NIGHT...VFR. SWLY MAY GUST TO 20 KT LATE IN THE DAY. TUESDAY AND TUESDAY NIGHT...PREDOMINATELY VFR. SCT SHRA AND ISO TSRA DURING THE AFTERNOON AND NIGHT COULD YIELD LOCAL MVFR/IFR CONDITIONS. WEDNESDAY...SHRA MAY LINGER INTO WEDNESDAY BUT MOST OF THE TERMINALS SHOULD DRY OUT. SOME MODEL SOLUTIONS ARE INDICATING EASTERLY WINDS TO DEVELOP. WILL HAVE TO WATCH FOR LOW CLOUDS AND MVFR CIGS TO ACCOMPANY MARINE LAYER. WEDNESDAY NIGHT AND THURSDAY...VFR. && .MARINE... SEAS AS OF 10 AM HAVE DROPPED TO 4.6 FEET AT BOTH BUOY9 AND 65. IN ADDITION, THE PERIOD HAS INCREASED TO AROUND 10 SECONDS. WITH THE DOWNWARD TREND UNDERWAY, WE WILL FINALLY PUT THIS SMALL CRAFT ADVISORY IN THE BOOKS AND HAVE NO FURTHER EXTENSION. WE ADJUSTED THE WINDS IN DELAWARE BAY THIS AFTERNOON AND EVE BASED ON HRRR AND ARW MODELS AS THEY HANDLED THE UP THE BAY BREEZE WELL YESTERDAY. NO ADDITIONAL FLAGS ARE EXPECTED DURG THE REMAINDER OF THE NR AND SHORT TERM PDS. OUTLOOK... MONDAY THROUGH THURSDAY...WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA. THE STRONGEST WINDS ARE EXPECTED MONDAY AND TUESDAY AS HIGH PRESSURE MOVES OFFSHORE AND A S-SW FLOW AROUND 15-20 KT ENSUES. && .FIRE WEATHER... RELATIVE HUMIDITY VALUES NEAR 30 PERCENT, ALONG WITH OCCASIONAL WIND GUSTS TO NEAR 20 MPH MAY ENHANCE THE FIRE WEATHER RISK LATE IN THE DAY ON MONDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...KLEIN/NIERENBERG MARINE...GIGI/KLEIN/NIERENBERG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1052 AM EDT SUN MAY 3 2015 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE OVER THE EASTERN UNITED STATES TODAY WILL GRADUALLY MOVE OFFSHORE ON MONDAY. A COLD FRONT IS FORECAST TO WEAKEN AS IT DROPS SOUTHWARD ACROSS THE AREA TUESDAY THROUGH EARLY WEDNESDAY. HIGH PRESSURE RETURNS LATE IN THE WEEK. THE HIGH WILL EVENTUALLY SHIFT OFF THE EAST COAST NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO BIG CHANGES MADE WITH THIS UPDATE. 12Z SOUNDINGS HAVE HIGH TEMPS REACHING THE 70S TODAY, BUT WITH CONTINUED AIR MASS MODIFICATION AND SOME WAA, SOME LOW 80S ARE POSSIBLE INLAND. SINCE THE HRRR DID PRETTY WELL WITH THE SEA BREEZE FRONT YESTERDAY, WE ADJUSTED WINDS BASED ON ITS LATEST RUN OR TWO. HIGH PRES WILL BE OVER THE SERN CONUS TODAY. SWLY FLOW WILL INCREASE AND TEMPS WILL WARM IN RESPONSE. HIGHS ARE EXPECTED TO BE IN THE MID TO UPPER 70S, WITH SOME LOCATIONS MAKING A RUN AT 80 DEGREES. NO PRECIP IS ANTICIPATED. THERE WILL BE SOME SCT CLOUDS ON AN OTHERWISE BEAUTIFUL DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... THE AREA OF HIGH PRES WILL MOVE EWD AND OFF THE CST AND A GENLY CLEAR SKY IS IN STORE WITH LIGHT WIND. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE CENTER OF SURFACE HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND MORE HUMID AIR UP THE EASTERN SEABOARD. MONDAY WILL CONTEND WITH APRIL 18TH FOR THE WARMEST DAY SO FAR THIS YEAR WITH HIGHS 80-85 DEGREES (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). CONDITIONS ACROSS THE FORECAST AREA WILL BE DRY THROUGH MONDAY NIGHT OWING TO STRONG SUBSIDENCE PRESENT BENEATH THE H8 RIDGE. A COLD FRONT WILL MOVE SLOWLY SOUTHWARD THROUGH THE AREA TUESDAY AFTERNOON AND NIGHT. CLOUDS OVERSPREADING NORTHEAST PA AND NORTHWEST NJ WILL RESULT IN SLIGHTLY COOLER HIGHS IN THE 70S ON TUESDAY. FARTHER SOUTH IN THE WARM SECTOR, HIGHS TUESDAY HAVE THE POTENTIAL TO BE CLOSE TO MONDAY`S FROM ABOUT PHILLY SOUTHWARD IF THE FRONT AND ITS ASSOCIATED CLOUD COVER HANGS BACK TO THE NORTH. MOISTURE WILL POOL ALONG THE FRONT AS NOTED BY PWATS INCREASING TO NEAR 1.5 INCHES AND SURFACE DEWPOINTS TO NEAR 60F BY THE AFTERNOON. BUFKIT SOUNDINGS FROM THE 00Z GFS AND 21Z SREF SHOW MODEST INSTABILITY (ML CAPE AROUND 500 J/KG) WHILE THE 00Z NAM DEPICTS A CONSIDERABLY MORE UNSTABLE ENVIRONMENT (ML CAPE AOA 1000 J/KG). WENT MORE CONSERVATIVE WITH FORECAST COVERAGE OF THUNDERSTORMS DUE TO THE PRESENCE OF WEAK SHEAR AND LIMITED FORCING IN ADDITION TO THE QUESTIONABLE INSTABILITY. A GENERAL WEAKENING TREND IS EXPECTED WITH THE CONVECTION AFTER SUNSET, ALTHOUGH SHOWERS MAY LINGER INTO THE OVERNIGHT AS SLIGHTLY BETTER LIFT ASSOCIATED WITH AN UPPER SHORTWAVE TROUGH ARRIVES LATE. THE FRONT MAY EITHER CONTINUE TO SAG SOUTHWARD SLOWLY OR EVEN STALL OVER THE DELMARVA WEDNESDAY MORNING. LIFT ASSOCIATED WITH THE FRONT ITSELF SHOULD WEAKEN AS THE BOUNDARY IS EXPECTED TO BECOME INCREASINGLY DIFFUSE. CONSEQUENTIALLY, COVERAGE OF SHOWERS EXPECTED TO BE RELATIVELY LOW ON WEDNESDAY. THUNDERSTORM CHANCES CONFINED TO THE LOWER DELMARVA, WHERE THESE LOCATIONS HAVE THE BEST CHANCE OF RESIDING IN THE WARM SECTOR TO THE SOUTH OF THE BOUNDARY. THE CAA BEHIND THE FRONT IS NOT SIGNIFICANT, SO THE TREND OF ABOVE NORMAL TEMPS SHOULD CONTINUE INTO WEDNESDAY. HOWEVER, WE WILL HAVE TO WATCH FOR THE POSSIBILITY OF ONSHORE FLOW TO DEVELOP. THIS MAY PREVENT TEMPS FROM REACHING 70F IN THE COASTAL PLAIN, ESPECIALLY THE EASTERLY WIND BECOMES ENHANCED BY A SEABREEZE. EXPANSIVE HIGH PRESSURE OVER THE EASTERN SEABOARD WILL PROVIDE A MAINLY DRY PATTERN THURSDAY THROUGH SATURDAY. THE HUMIDITY IS FORECAST TO INCREASE A BIT FRIDAY AND SATURDAY AS SOUTHERLY RETURN FLOW DEVELOPS WITH THE SURFACE HIGH MOVING OFFSHORE. CANNOT RULE OUT THE POSSIBILITY OF A A SHOWER DEVELOPING DURING THE AFTERNOON HOURS FRIDAY AND SATURDAY BUT THE SUBSIDENCE INVERSION UNDERNEATH THE RIDGE SHOULD MINIMIZE THE CONVECTIVE POTENTIAL. ABOVE NORMAL TEMPS WILL PERSIST WITH HIGHS IN THE 70S TO NEAR 80F EACH DAY. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDS WILL PREVAIL THRU THE TAF PD WITH HIGH PRES TO THE SE TODAY MOVG OFFSHORE TONIGHT. THE FLOW WILL BECOME SWLY BY AFTN BUT WILL BE LESS THAN 10 KTS. ONLY SCT CLOUDS ARE ANTICIPATED. WITH LIGHT FLOW, STILL EXPECTING ANOTHER SEA BREEZE AT KACY AND KMIV. AT THESE LOCATIONS, WIND COULD REACH 10 KT OR SO. OUTLOOK... MONDAY AND MONDAY NIGHT...VFR. SWLY MAY GUST TO 20 KT LATE IN THE DAY. TUESDAY AND TUESDAY NIGHT...PREDOMINATELY VFR. SCT SHRA AND ISO TSRA DURING THE AFTERNOON AND NIGHT COULD YIELD LOCAL MVFR/IFR CONDITIONS. WEDNESDAY...SHRA MAY LINGER INTO WEDNESDAY BUT MOST OF THE TERMINALS SHOULD DRY OUT. SOME MODEL SOLUTIONS ARE INDICATING EASTERLY WINDS TO DEVELOP. WILL HAVE TO WATCH FOR LOW CLOUDS AND MVFR CIGS TO ACCOMPANY MARINE LAYER. WEDNESDAY NIGHT AND THURSDAY...VFR. && .MARINE... SEAS AS OF 10 AM HAVE DROPPED TO 4.6 FEET AT BOTH BUOY9 AND 65. IN ADDITION, THE PERIOD HAS INCREASED TO AROUND 10 SECONDS. WITH THE DOWNWARD TREND UNDERWAY, WE WILL FINALLY PUT THIS SMALL CRAFT ADVISORY IN THE BOOKS AND HAVE NO FURTHER EXTENSION. WE ADJUSTED THE WINDS IN DELAWARE BAY THIS AFTERNOON AND EVE BASED ON HRRR AND ARW MODELS AS THEY HANDLED THE UP THE BAY BREEZE WELL YESTERDAY. NO ADDITIONAL FLAGS ARE EXPECTED DURG THE REMAINDER OF THE NR AND SHORT TERM PDS. OUTLOOK... MONDAY THROUGH THURSDAY...WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA. THE STRONGEST WINDS ARE EXPECTED MONDAY AND TUESDAY AS HIGH PRESSURE MOVES OFFSHORE AND A S-SW FLOW AROUND 15-20 KT ENSUES. && .FIRE WEATHER... RELATIVE HUMIDITY VALUES NEAR 30 PERCENT, ALONG WITH OCCASIONAL WIND GUSTS TO NEAR 20 MPH MAY ENHANCE THE FIRE WEATHER RISK LATE IN THE DAY ON MONDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...KLEIN/NIERENBERG MARINE...GIGI/KLEIN/NIERENBERG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
920 AM EDT SUN MAY 3 2015 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE OVER THE EASTERN UNITED STATES TODAY WILL GRADUALLY MOVE OFFSHORE ON MONDAY. A COLD FRONT IS FORECAST TO WEAKEN AS IT DROPS SOUTHWARD ACROSS THE AREA TUESDAY THROUGH EARLY WEDNESDAY. HIGH PRESSURE RETURNS LATE IN THE WEEK. THE HIGH WILL EVENTUALLY SHIFT OFF THE EAST COAST NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO BIG CHANGES MADE WITH THIS UPDATE. 12Z SOUNDINGS HAVE HIGH TEMPS REACHING THE 70S TODAY, BUT WITH CONTINUED AIR MASS MODIFICATION AND SOME WAA, SOME LOW 80S ARE POSSIBLE INLAND. SINCE THE HRRR DID PRETTY WELL WITH THE SEA BREEZE FRONT YESTERDAY, WE ADJUSTED WINDS BASED ON ITS LATEST RUN OR TWO. HIGH PRES WILL BE OVER THE SERN CONUS TODAY. SWLY FLOW WILL INCREASE AND TEMPS WILL WARM IN RESPONSE. HIGHS ARE EXPECTED TO BE IN THE MID TO UPPER 70S, WITH SOME LOCATIONS MAKING A RUN AT 80 DEGREES. NO PRECIP IS ANTICIPATED. THERE WILL BE SOME SCT CLOUDS ON AN OTHERWISE BEAUTIFUL DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... THE AREA OF HIGH PRES WILL MOVE EWD AND OFF THE CST AND A GENLY CLEAR SKY IS IN STORE WITH LIGHT WIND. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE CENTER OF SURFACE HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST ON MONDAY. SOUTHWESTERLY RETURN FLOW AROUND THE HIGH WILL DRAW EVEN WARMER AND MORE HUMID AIR UP THE EASTERN SEABOARD. MONDAY WILL CONTEND WITH APRIL 18TH FOR THE WARMEST DAY SO FAR THIS YEAR WITH HIGHS 80-85 DEGREES (EXCEPT COOLER ALONG THE COAST AND IN THE POCONOS). CONDITIONS ACROSS THE FORECAST AREA WILL BE DRY THROUGH MONDAY NIGHT OWING TO STRONG SUBSIDENCE PRESENT BENEATH THE H8 RIDGE. A COLD FRONT WILL MOVE SLOWLY SOUTHWARD THROUGH THE AREA TUESDAY AFTERNOON AND NIGHT. CLOUDS OVERSPREADING NORTHEAST PA AND NORTHWEST NJ WILL RESULT IN SLIGHTLY COOLER HIGHS IN THE 70S ON TUESDAY. FARTHER SOUTH IN THE WARM SECTOR, HIGHS TUESDAY HAVE THE POTENTIAL TO BE CLOSE TO MONDAY`S FROM ABOUT PHILLY SOUTHWARD IF THE FRONT AND ITS ASSOCIATED CLOUD COVER HANGS BACK TO THE NORTH. MOISTURE WILL POOL ALONG THE FRONT AS NOTED BY PWATS INCREASING TO NEAR 1.5 INCHES AND SURFACE DEWPOINTS TO NEAR 60F BY THE AFTERNOON. BUFKIT SOUNDINGS FROM THE 00Z GFS AND 21Z SREF SHOW MODEST INSTABILITY (ML CAPE AROUND 500 J/KG) WHILE THE 00Z NAM DEPICTS A CONSIDERABLY MORE UNSTABLE ENVIRONMENT (ML CAPE AOA 1000 J/KG). WENT MORE CONSERVATIVE WITH FORECAST COVERAGE OF THUNDERSTORMS DUE TO THE PRESENCE OF WEAK SHEAR AND LIMITED FORCING IN ADDITION TO THE QUESTIONABLE INSTABILITY. A GENERAL WEAKENING TREND IS EXPECTED WITH THE CONVECTION AFTER SUNSET, ALTHOUGH SHOWERS MAY LINGER INTO THE OVERNIGHT AS SLIGHTLY BETTER LIFT ASSOCIATED WITH AN UPPER SHORTWAVE TROUGH ARRIVES LATE. THE FRONT MAY EITHER CONTINUE TO SAG SOUTHWARD SLOWLY OR EVEN STALL OVER THE DELMARVA WEDNESDAY MORNING. LIFT ASSOCIATED WITH THE FRONT ITSELF SHOULD WEAKEN AS THE BOUNDARY IS EXPECTED TO BECOME INCREASINGLY DIFFUSE. CONSEQUENTIALLY, COVERAGE OF SHOWERS EXPECTED TO BE RELATIVELY LOW ON WEDNESDAY. THUNDERSTORM CHANCES CONFINED TO THE LOWER DELMARVA, WHERE THESE LOCATIONS HAVE THE BEST CHANCE OF RESIDING IN THE WARM SECTOR TO THE SOUTH OF THE BOUNDARY. THE CAA BEHIND THE FRONT IS NOT SIGNIFICANT, SO THE TREND OF ABOVE NORMAL TEMPS SHOULD CONTINUE INTO WEDNESDAY. HOWEVER, WE WILL HAVE TO WATCH FOR THE POSSIBILITY OF ONSHORE FLOW TO DEVELOP. THIS MAY PREVENT TEMPS FROM REACHING 70F IN THE COASTAL PLAIN, ESPECIALLY THE EASTERLY WIND BECOMES ENHANCED BY A SEABREEZE. EXPANSIVE HIGH PRESSURE OVER THE EASTERN SEABOARD WILL PROVIDE A MAINLY DRY PATTERN THURSDAY THROUGH SATURDAY. THE HUMIDITY IS FORECAST TO INCREASE A BIT FRIDAY AND SATURDAY AS SOUTHERLY RETURN FLOW DEVELOPS WITH THE SURFACE HIGH MOVING OFFSHORE. CANNOT RULE OUT THE POSSIBILITY OF A A SHOWER DEVELOPING DURING THE AFTERNOON HOURS FRIDAY AND SATURDAY BUT THE SUBSIDENCE INVERSION UNDERNEATH THE RIDGE SHOULD MINIMIZE THE CONVECTIVE POTENTIAL. ABOVE NORMAL TEMPS WILL PERSIST WITH HIGHS IN THE 70S TO NEAR 80F EACH DAY. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDS WILL PREVAIL THRU THE TAF PD WITH HIGH PRES TO THE SE TODAY MOVG OFFSHORE TONIGHT. THE FLOW WILL BECOME SWLY BY AFTN BUT WILL BE LESS THAN 10 KTS. ONLY SCT CLOUDS ARE ANTICIPATED. WITH LIGHT FLOW, STILL EXPECTING ANOTHER SEA BREEZE AT KACY AND KMIV. AT THESE LOCATIONS, WIND COULD REACH 10 KT OR SO. OUTLOOK... MONDAY AND MONDAY NIGHT...VFR. SWLY MAY GUST TO 20 KT LATE IN THE DAY. TUESDAY AND TUESDAY NIGHT...PREDOMINATELY VFR. SCT SHRA AND ISO TSRA DURING THE AFTERNOON AND NIGHT COULD YIELD LOCAL MVFR/IFR CONDITIONS. WEDNESDAY...SHRA MAY LINGER INTO WEDNESDAY BUT MOST OF THE TERMINALS SHOULD DRY OUT. SOME MODEL SOLUTIONS ARE INDICATING EASTERLY WINDS TO DEVELOP. WILL HAVE TO WATCH FOR LOW CLOUDS AND MVFR CIGS TO ACCOMPANY MARINE LAYER. WEDNESDAY NIGHT AND THURSDAY...VFR. && .MARINE... DOGGEDLY PERSISTENT 5 FOOT SEAS NOW HAVE MADE IT INTO ALL OF OUR MARINE ZONES. WE HAVE EXTENDED THE SCA THROUGH ALL OUR WATERS FOR THIS MORNING. SINCE WINDS ARE NOW WELL BELOW SCA THRESHOLD FOR WINDS, WE CONVERTED THE SCA OVER TO HAZARDOUS SEAS ALL OCEAN ZONES. ONCE THIS SCA COMES DOWN, NO ADDITIONAL FLAGS ARE EXPECTED DURG THE REMAINDER OF THE NR AND SHORT TERM PDS. OUTLOOK... MONDAY THROUGH THURSDAY...WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA. THE STRONGEST WINDS ARE EXPECTED MONDAY AND TUESDAY AS HIGH PRESSURE MOVES OFFSHORE AND A S-SW FLOW AROUND 15-20 KT ENSUES. && .FIRE WEATHER... RELATIVE HUMIDITY VALUES NEAR 30 PERCENT, ALONG WITH OCCASIONAL WIND GUSTS TO NEAR 20 MPH MAY ENHANCE THE FIRE WEATHER RISK LATE IN THE DAY ON MONDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM EDT THIS MORNING FOR ANZ450>455. && $$ SYNOPSIS...KLEIN NEAR TERM...GIGI/NIERENBERG SHORT TERM...NIERENBERG LONG TERM...KLEIN AVIATION...KLEIN/NIERENBERG MARINE...GIGI/KLEIN/NIERENBERG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS MIAMI FL
140 PM EDT SUN MAY 3 2015 .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD. WINDS THIS AFTERNOON WILL CONTINUE TO BE OUT OF THE EAST BETWEEN 15 TO 20 KNOTS WITH HIGHER GUSTS POSSIBLE. WINDS WILL SLIGHTLY SUBSIDE DURING THE OVERNIGHT HOURS, HOWEVER, THEY ARE EXPECTED TO INCREASE TO 15 TO 20 KNOTS AGAIN ON MONDAY MORNING WITH HIGHER GUSTS ONCE AGAIN POSSIBLE. && .PREV DISCUSSION... /ISSUED 954 AM EDT SUN MAY 3 2015/ UPDATE... THE CURRENT MODEL ANALYSIS SHOWS MOSTLY ZONAL FLOW ACROSS THE FLORIDA PENINSULA WITH A VERY WEAK MID LEVEL TROUGH OVER SOUTH FLORIDA. AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE EXISTS ACROSS THE SOUTHEAST STATES CENTERED FROM WEST VIRGINIA TO NORTHERN GEORGIA. THE MID LEVEL TROUGH IS REFLECTED WELL ON THE 12Z MFL SOUNDING SHOWING A NORTH-NORTHEAST WIND IN THE LAYER FROM 600MB TO 450MB WITH WESTERLY FLOW ABOVE AND BELOW THAT. LOW LEVEL FLOW IS EAST-NORTHEAST WITH THE HIGH PRESSURE CENTERED TO THE NORTH. THE SURFACE HIGH WILL RAPIDLY SHIFT EAST TODAY IN RESPONSE TO A COLD FRONT THAT WILL MOVE INTO THE CENTRAL PORTION OF THE CONTINENTAL U.S. WITH THE PRESSURE GRADIENT TIGHTENING ACROSS SOUTH FLORIDA BY EARLY THIS AFTERNOON. THIS WILL KEEP THE HIGH RISK OF RIP CURRENTS AT THE ATLANTIC BEACHES WITH MIAMI BEACH OCEAN RESCUE ALREADY REPORTING STRONG CURRENTS THIS MORNING. THE 12Z SOUNDING ALSO SHOWS A VERY STABLE AIRMASS LAYER BETWEEN 850MB AND 750MB SO THIS WILL CONTINUE TO KEEP RAIN CHANCES OUT OF THE FORECAST ALTHOUGH THE HRRR IS INDICATING THE POSSIBILITY OF A COUPLE OF QUICK PASSING SHOWERS. HOWEVER, IT IS ONLY DEPICTING 20-25 DBZ INTENSITY SO NOT WORTH MENTIONING AT THIS TIME AND THE HRRR OFTEN TIMES OVER EMPHASIZES SHOWERS IN A DRY EASTERLY FLOW REGIME. BUT STILL, SOMETHING TO MONITOR. FOR THE MARINE FORECAST, DO NOT PLAN ANY CHANGES AT THIS TIME. HOWEVER, THE LATEST GFS MODEL GUIDANCE IS SHOWING A TAD BIT STRONGER WINDS OVER THE ATLANTIC WATERS THIS AFTERNOON THAN IS CURRENTLY DEPICTED. DUE TO THIS BEING FROM THE INTERMEDIATE RUN AT 06Z AND ONLY ONE UPDATE SHOWING THIS, WILL WAIT FOR THE 12Z RUN TO MAKE ANY DECISIONS BUT MAY NEED TO BUMP UP THE WIND TO 20 KNOTS FROM THE CURRENT 15-20 KNOTS WHICH COULD AFFECT THE SIGNIFICANT WAVE HEIGHTS AS WELL AND MAY NEED TO BEGIN THE SCA FOR THOSE WATERS EARLIER THAN THE 00Z START NOW. KOB PREV DISCUSSION... /ISSUED 744 AM EDT SUN MAY 3 2015/ AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY MORNING HOURS AND THROUGH THE AFTERNOON WITH MAINLY STABLE WEATHER CONDITIONS ANTICIPATED. AS HIGH PRESSURE BUILDS...EAST NORTHEAST WINDS FORECAST TO INCREASE TO THE 15 TO 20 KNOTS RANGE BY LATE MORNING WITH HIGHER GUSTS POSSIBLE AND SUBSIDING OVERNIGHT BUT STILL REMAINING AROUND 10-15 KTS EXCEPT AROUND 10 KNOTS AT APF AND TMB. PREV DISCUSSION... /ISSUED 433 AM EDT SUN MAY 3 2015/ DISCUSSION... THE REGIONAL SYNOPTIC FEATURES EARLY THIS MORNING INCLUDE A WEAK SURFACE TROUGH JUST WEST OF THE KEYS AND EXTENDING NORTHWARD...A MID TO UPPER LEVEL TROUGH EXTENDING INTO THE CENTRAL TO EASTERN GULF AND A COLD FRONT ACROSS EASTERN CUBA THAT EXTENDS NORTHWARD TO A SURFACE LOW NORTHEAST OF THE MID-ATLANTIC STATES. FOR TODAY...HIGH PRESSURE WILL SLOWLY DEVELOP OFF THE GEORGIA/CAROLINAS COAST WITH THE AFOREMENTIONED SURFACE TROUGH ERODING. IN ADDITION DEEPER LAYERED MOISTURE WILL LIKELY REMAIN ACROSS THE KEYS TODAY. WITH HIGHER PRESSURE BUILDING INTO THE REGION THE WEST COAST SEA BREEZE WILL BE SUPPRESSED AND WITH PWAT EXPECTED TO BE AROUND ONLY AN INCH CONVECTION IS NOT LIKELY TODAY ALTHOUGH SOME ISOLATED SHOWER ACTIVITY IS POSSIBLE ACROSS THE SOUTHERN TIP OF THE PENINSULA. THERE WILL BE A HIGH RISK OF RIP CURRENTS ALONG THE ATLANTIC COAST BEACHES TODAY AND TONIGHT WITH A LONG PERIOD NORTHEASTERLY SWELL IN THE 2 TO 4 FOOT RANGE FORECAST TO ENTER THE ATLANTIC WATERS EAST OF PALM BEACH COUNTY THIS MORNING...WITH THE GREATEST IMPACT EXPECTED ACROSS THE WATERS TO THE EAST OF PALM BEACH COUNTY. FOR MONDAY...MOISTURE AND CLOUDINESS WILL BEGIN TO RETURN TO THE REGION. THE MID TO UPPER LEVEL TROUGH ACROSS THE GULF IS FORECAST TO DEEPEN WITH THE FLORIDA PENINSULA TO THE EAST OF THE TROUGH AXIS. THE LOW LEVEL FLOW WILL BECOME SOUTHERLY BRINGING DEEP MOISTURE ACROSS CUBA NORTHWARD INTO THE REGION. MODERATE EASTERLY WINDS WILL FAVOR SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS MAINLY ALONG THE EASTERN THIRD OF THE PENINSULA AND THE ADJACENT ATLANTIC WATERS. FOR TUESDAY...PREVIOUS DISCUSSIONS HAVE ALREADY INDICATED THAT DEEP TROPICAL MOISTURE IS FORECAST TO ENTER ON TUESDAY WITH THE MID TO UPPER LEVEL TROUGH AXIS JUST WEST OF FLORIDA AND A BROAD LOW LEVEL TROUGH DEVELOPING ACROSS THE FLORIDA STRAITS AND EXTENDING INTO THE NORTHWEST BAHAMAS. THE PWAT IS FORECAST TO BE ABOUT 1.7 INCHES AND MID LEVEL TEMPERATURES FORECAST TO BE SIGNIFICANTLY COOL FOR THIS TIME OF YEAR...ABOUT 3 DEGREES COOLER. ALL THESE FACTORS ARE FORECAST TO BRING SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS TO THE REGION ON TUESDAY WITH A SYNOPTIC PATTERN SUPPORTIVE OF LOCALLY HEAVY RAINFALL WITH FLOODING POTENTIAL POSSIBLE IN ISOLATED AREAS. BY WEDNESDAY THE GLOBAL MODELS START TO DIVERGE SOME IN THEIR SOLUTIONS BUT THE GFS ENSEMBLE SHOWS BROAD FEATURES THAT SEEM LIKE A GENERAL CONSENSUS BETWEEN THE GFS AND THE ECMWF. THE ENSEMBLE INDICATES THAT THE UPPER LEVEL TROUGH AXIS IS FORECAST TO SHIFT EAST ACROSS THE FLORIDA PENINSULA WITH A BROAD LOW LEVEL AND SURFACE TROUGH OFF THE EAST CENTRAL FLORIDA COAST WITH DEEP MOISTURE EXTENDING ACROSS SOUTH FLORIDA. SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS ARE FORECAST WITH A SYNOPTIC PATTERN AGAIN SUPPORTIVE OF LOCALLY HEAVY RAINFALL. FOR THE EXTENDED FORECAST...BY THURSDAY THE ECMWF...GFS AND THE GFS ENSEMBLE HAVE BROAD AGREEMENT THAT THE UPPER LEVEL TROUGH WILL PERSIST NEAR THE FLORIDA PENINSULA WITH A CLOSED SURFACE LOW FORECAST OFF THE NORTHEAST FLORIDA COAST. THE GUIDANCE GENERALLY SUGGESTS THAT THE LOW COULD SLOWLY DRIFT TO THE NORTHWEST INTO NEXT WEEKEND. OBVIOUSLY ITS TOO EARLY TO SPECULATE ON THIS SCENARIO AND WHAT IF ANY IMPACT IT MIGHT HAVE FOR SOUTH FLORIDA AND WILL HAVE TO WAIT AND SEE WHAT CONSENSUS THE GUIDANCE HAS DURING THIS WEEK. MARINE... A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE GULF WATERS FOR WINDS TO NEAR 20 KNOTS OR JUST ABOVE THROUGH 10 AM. WINDS ARE FORECAST TO SLOWLY DECREASE TODAY THEN INCREASE AGAIN TO 20 KNOTS OR JUST ABOVE MAINLY ACROSS THE OFF SHORE WATERS. THEREFORE THE SMALL CRAFT ADVISORY WILL BE ALLOWED TO EXPIRE THIS MORNING BUT A NEW ONE WILL BE ISSUED FOR TONIGHT...STARTING AT 00Z FOR THE OFF SHORE GULF WATERS. WITH THE COMBINATION OF NORTHEASTERLY WINDS IN THE 15 TO 20 KNOT RANGE ACROSS THE ATLANTIC WATERS AND A LONG PERIOD NORTHEASTERLY SWELL IN THE 2 TO 4 FOOT RANGE FORECAST TO ENTER THE ATLANTIC WATERS EAST OF PALM BEACH COUNTY LATER THIS MORNING...HAZARDOUS SEAS TO NEAR 7 FEET ARE FORECAST ACROSS THE ATLANTIC WATERS WITH A SMALL CRAFT ADVISORY IN EFFECT TODAY STARTING AT 18Z THROUGH 00Z TUESDAY BUT MAY HAVE TO BE EXTENDED WITH LATER GUIDANCE. THERE IS A LOT OF UNCERTAINTY IN THE EXTENDED FORECAST GIVEN THE UNCERTAINTIES OUTLINED IN THE DISCUSSION ABOVE. SO THERE COULD BE CONSIDERABLE CHANGES TO THE WIND AND WAVES FORECAST IN THE EXTENDED PERIODS IN THE NEXT FEW DAYS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 69 82 73 78 / 0 20 60 70 FORT LAUDERDALE 71 82 73 80 / 10 20 70 70 MIAMI 70 82 72 81 / 10 20 70 70 NAPLES 63 86 67 86 / 10 10 20 60 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...HIGH RIP CURRENT RISK UNTIL MIDNIGHT EDT TONIGHT FOR FLZ168-172- 173. AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM EDT MONDAY FOR AMZ650-651-670-671. GM...SMALL CRAFT ADVISORY FOR WINDS FROM 8 PM THIS EVENING TO 8 AM EDT MONDAY FOR GMZ676. && $$ SHORT TERM...52/PS LONG TERM....52/PS AVIATION...55/CWC
AREA FORECAST DISCUSSION
NWS MIAMI FL
954 AM EDT SUN MAY 3 2015 .UPDATE... THE CURRENT MODEL ANALYSIS SHOWS MOSTLY ZONAL FLOW ACROSS THE FLORIDA PENINSULA WITH A VERY WEAK MID LEVEL TROUGH OVER SOUTH FLORIDA. AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE EXISTS ACROSS THE SOUTHEAST STATES CENTERED FROM WEST VIRGINIA TO NORTHERN GEORGIA. THE MID LEVEL TROUGH IS REFLECTED WELL ON THE 12Z MFL SOUNDING SHOWING A NORTH-NORTHEAST WIND IN THE LAYER FROM 600MB TO 450MB WITH WESTERLY FLOW ABOVE AND BELOW THAT. LOW LEVEL FLOW IS EAST-NORTHEAST WITH THE HIGH PRESSURE CENTERED TO THE NORTH. THE SURFACE HIGH WILL RAPIDLY SHIFT EAST TODAY IN RESPONSE TO A COLD FRONT THAT WILL MOVE INTO THE CENTRAL PORTION OF THE CONTINENTAL U.S. WITH THE PRESSURE GRADIENT TIGHTENING ACROSS SOUTH FLORIDA BY EARLY THIS AFTERNOON. THIS WILL KEEP THE HIGH RISK OF RIP CURRENTS AT THE ATLANTIC BEACHES WITH MIAMI BEACH OCEAN RESCUE ALREADY REPORTING STRONG CURRENTS THIS MORNING. THE 12Z SOUNDING ALSO SHOWS A VERY STABLE AIRMASS LAYER BETWEEN 850MB AND 750MB SO THIS WILL CONTINUE TO KEEP RAIN CHANCES OUT OF THE FORECAST ALTHOUGH THE HRRR IS INDICATING THE POSSIBILITY OF A COUPLE OF QUICK PASSING SHOWERS. HOWEVER, IT IS ONLY DEPICTING 20-25 DBZ INTENSITY SO NOT WORTH MENTIONING AT THIS TIME AND THE HRRR OFTEN TIMES OVER EMPHASIZES SHOWERS IN A DRY EASTERLY FLOW REGIME. BUT STILL, SOMETHING TO MONITOR. FOR THE MARINE FORECAST, DO NOT PLAN ANY CHANGES AT THIS TIME. HOWEVER, THE LATEST GFS MODEL GUIDANCE IS SHOWING A TAD BIT STRONGER WINDS OVER THE ATLANTIC WATERS THIS AFTERNOON THAN IS CURRENTLY DEPICTED. DUE TO THIS BEING FROM THE INTERMEDIATE RUN AT 06Z AND ONLY ONE UPDATE SHOWING THIS, WILL WAIT FOR THE 12Z RUN TO MAKE ANY DECISIONS BUT MAY NEED TO BUMP UP THE WIND TO 20 KNOTS FROM THE CURRENT 15-20 KNOTS WHICH COULD AFFECT THE SIGNIFICANT WAVE HEIGHTS AS WELL AND MAY NEED TO BEGIN THE SCA FOR THOSE WATERS EARLIER THAN THE 00Z START NOW. KOB && .PREV DISCUSSION... /ISSUED 744 AM EDT SUN MAY 3 2015/ AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY MORNING HOURS AND THROUGH THE AFTERNOON WITH MAINLY STABLE WEATHER CONDITIONS ANTICIPATED. AS HIGH PRESSURE BUILDS...EAST NORTHEAST WINDS FORECAST TO INCREASE TO THE 15 TO 20 KNOTS RANGE BY LATE MORNING WITH HIGHER GUSTS POSSIBLE AND SUBSIDING OVERNIGHT BUT STILL REMAINING AROUND 10-15 KTS EXCEPT AROUND 10 KNOTS AT APF AND TMB. PREV DISCUSSION... /ISSUED 433 AM EDT SUN MAY 3 2015/ DISCUSSION... THE REGIONAL SYNOPTIC FEATURES EARLY THIS MORNING INCLUDE A WEAK SURFACE TROUGH JUST WEST OF THE KEYS AND EXTENDING NORTHWARD...A MID TO UPPER LEVEL TROUGH EXTENDING INTO THE CENTRAL TO EASTERN GULF AND A COLD FRONT ACROSS EASTERN CUBA THAT EXTENDS NORTHWARD TO A SURFACE LOW NORTHEAST OF THE MID-ATLANTIC STATES. FOR TODAY...HIGH PRESSURE WILL SLOWLY DEVELOP OFF THE GEORGIA/CAROLINAS COAST WITH THE AFOREMENTIONED SURFACE TROUGH ERODING. IN ADDITION DEEPER LAYERED MOISTURE WILL LIKELY REMAIN ACROSS THE KEYS TODAY. WITH HIGHER PRESSURE BUILDING INTO THE REGION THE WEST COAST SEA BREEZE WILL BE SUPPRESSED AND WITH PWAT EXPECTED TO BE AROUND ONLY AN INCH CONVECTION IS NOT LIKELY TODAY ALTHOUGH SOME ISOLATED SHOWER ACTIVITY IS POSSIBLE ACROSS THE SOUTHERN TIP OF THE PENINSULA. THERE WILL BE A HIGH RISK OF RIP CURRENTS ALONG THE ATLANTIC COAST BEACHES TODAY AND TONIGHT WITH A LONG PERIOD NORTHEASTERLY SWELL IN THE 2 TO 4 FOOT RANGE FORECAST TO ENTER THE ATLANTIC WATERS EAST OF PALM BEACH COUNTY THIS MORNING...WITH THE GREATEST IMPACT EXPECTED ACROSS THE WATERS TO THE EAST OF PALM BEACH COUNTY. FOR MONDAY...MOISTURE AND CLOUDINESS WILL BEGIN TO RETURN TO THE REGION. THE MID TO UPPER LEVEL TROUGH ACROSS THE GULF IS FORECAST TO DEEPEN WITH THE FLORIDA PENINSULA TO THE EAST OF THE TROUGH AXIS. THE LOW LEVEL FLOW WILL BECOME SOUTHERLY BRINGING DEEP MOISTURE ACROSS CUBA NORTHWARD INTO THE REGION. MODERATE EASTERLY WINDS WILL FAVOR SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS MAINLY ALONG THE EASTERN THIRD OF THE PENINSULA AND THE ADJACENT ATLANTIC WATERS. FOR TUESDAY...PREVIOUS DISCUSSIONS HAVE ALREADY INDICATED THAT DEEP TROPICAL MOISTURE IS FORECAST TO ENTER ON TUESDAY WITH THE MID TO UPPER LEVEL TROUGH AXIS JUST WEST OF FLORIDA AND A BROAD LOW LEVEL TROUGH DEVELOPING ACROSS THE FLORIDA STRAITS AND EXTENDING INTO THE NORTHWEST BAHAMAS. THE PWAT IS FORECAST TO BE ABOUT 1.7 INCHES AND MID LEVEL TEMPERATURES FORECAST TO BE SIGNIFICANTLY COOL FOR THIS TIME OF YEAR...ABOUT 3 DEGREES COOLER. ALL THESE FACTORS ARE FORECAST TO BRING SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS TO THE REGION ON TUESDAY WITH A SYNOPTIC PATTERN SUPPORTIVE OF LOCALLY HEAVY RAINFALL WITH FLOODING POTENTIAL POSSIBLE IN ISOLATED AREAS. BY WEDNESDAY THE GLOBAL MODELS START TO DIVERGE SOME IN THEIR SOLUTIONS BUT THE GFS ENSEMBLE SHOWS BROAD FEATURES THAT SEEM LIKE A GENERAL CONSENSUS BETWEEN THE GFS AND THE ECMWF. THE ENSEMBLE INDICATES THAT THE UPPER LEVEL TROUGH AXIS IS FORECAST TO SHIFT EAST ACROSS THE FLORIDA PENINSULA WITH A BROAD LOW LEVEL AND SURFACE TROUGH OFF THE EAST CENTRAL FLORIDA COAST WITH DEEP MOISTURE EXTENDING ACROSS SOUTH FLORIDA. SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS ARE FORECAST WITH A SYNOPTIC PATTERN AGAIN SUPPORTIVE OF LOCALLY HEAVY RAINFALL. FOR THE EXTENDED FORECAST...BY THURSDAY THE ECMWF...GFS AND THE GFS ENSEMBLE HAVE BROAD AGREEMENT THAT THE UPPER LEVEL TROUGH WILL PERSIST NEAR THE FLORIDA PENINSULA WITH A CLOSED SURFACE LOW FORECAST OFF THE NORTHEAST FLORIDA COAST. THE GUIDANCE GENERALLY SUGGESTS THAT THE LOW COULD SLOWLY DRIFT TO THE NORTHWEST INTO NEXT WEEKEND. OBVIOUSLY ITS TOO EARLY TO SPECULATE ON THIS SCENARIO AND WHAT IF ANY IMPACT IT MIGHT HAVE FOR SOUTH FLORIDA AND WILL HAVE TO WAIT AND SEE WHAT CONSENSUS THE GUIDANCE HAS DURING THIS WEEK. MARINE... A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE GULF WATERS FOR WINDS TO NEAR 20 KNOTS OR JUST ABOVE THROUGH 10 AM. WINDS ARE FORECAST TO SLOWLY DECREASE TODAY THEN INCREASE AGAIN TO 20 KNOTS OR JUST ABOVE MAINLY ACROSS THE OFF SHORE WATERS. THEREFORE THE SMALL CRAFT ADVISORY WILL BE ALLOWED TO EXPIRE THIS MORNING BUT A NEW ONE WILL BE ISSUED FOR TONIGHT...STARTING AT 00Z FOR THE OFF SHORE GULF WATERS. WITH THE COMBINATION OF NORTHEASTERLY WINDS IN THE 15 TO 20 KNOT RANGE ACROSS THE ATLANTIC WATERS AND A LONG PERIOD NORTHEASTERLY SWELL IN THE 2 TO 4 FOOT RANGE FORECAST TO ENTER THE ATLANTIC WATERS EAST OF PALM BEACH COUNTY LATER THIS MORNING...HAZARDOUS SEAS TO NEAR 7 FEET ARE FORECAST ACROSS THE ATLANTIC WATERS WITH A SMALL CRAFT ADVISORY IN EFFECT TODAY STARTING AT 18Z THROUGH 00Z TUESDAY BUT MAY HAVE TO BE EXTENDED WITH LATER GUIDANCE. THERE IS A LOT OF UNCERTAINTY IN THE EXTENDED FORECAST GIVEN THE UNCERTAINTIES OUTLINED IN THE DISCUSSION ABOVE. SO THERE COULD BE CONSIDERABLE CHANGES TO THE WIND AND WAVES FORECAST IN THE EXTENDED PERIODS IN THE NEXT FEW DAYS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 79 69 82 73 / 10 0 20 60 FORT LAUDERDALE 80 71 82 73 / 10 10 20 70 MIAMI 81 70 82 72 / 10 10 20 70 NAPLES 87 63 86 67 / 10 10 10 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...HIGH RIP CURRENT RISK THROUGH THIS EVENING FOR FLZ168-172-173. AM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 AM EDT THIS MORNING FOR AMZ651-671. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM THIS AFTERNOON TO 8 PM EDT MONDAY FOR AMZ650-651-670-671. GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 AM EDT THIS MORNING FOR GMZ656-657-676. SMALL CRAFT ADVISORY FOR WINDS FROM 8 PM THIS EVENING TO 8 AM EDT MONDAY FOR GMZ676. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
900 PM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 848 PM CDT MON MAY 4 2015 LATEST SURFACE ANALYSIS HAS A NEARLY STATIONARY FRONTAL BOUNDARY CUTTING WEST TO EAST ACROSS CENTRAL ILLINOIS ROUGHLY FROM QUINCY TO PARIS. THIS BOUNDARY IS FAIRLY WELL DELINEATED BY AN EXPANDING FINE LINE OF SHOWERS AND ISOLATED THUNDERSTORMS. THE PREVIOUS INTENSITY OF THE AREA OF STORMS PUSHING INTO WEST-CENTRAL ILLINOIS HAS FADED WITH THE LOSS OF DIURNAL INSTABILITY WITH THE BULK OF THE STORMS IN OUR VICINITY CURRENTLY OF THE "GARDEN VARIETY". THE BULK OF THE GUIDANCE, ESPECIALLY RECENT RUNS OF MANY HIGH RESOLUTION MODELS, SUGGEST THE BULK OF THE SHOWERS/STORMS THOUGH THE NIGHT WILL EXIST ALONG/NORTH OF THE FRONTAL BOUNDARY. ALSO, A WAVE LIFTING NORTHEAST OUT OF THE PLAINS IS EXPECTED TO HELP PUSH THE FRONT A LITTLE FURTHER NORTH WITH TIME OVERNIGHT. THESE FACTORS WOULD SUGGEST THE BULK OF THE UPSTREAM PRECIPITATION OVER IOWA AND MISSOURI WOULD TRACK NORTH OF MOST OF THE FORECAST AREA. PLAN TO UPDATE FORECAST TO REFINE POPS, MAINLY TO PUSH THE RISK FURTHER NORTH. OTHERWISE, MINOR TWEAKS ARE NEEDED FOR THE LATEST HOURLY TRENDS. && .SHORT TERM...(TONIGHT) ISSUED AT 245 PM CDT MON MAY 4 2015 FRONTAL BOUNDARY EXTENDING FROM SOUTHERN LAKE MICHIGAN TO NORTHERN KANSAS WILL SINK SOUTHWARD...EVENTUALLY STALLING NEAR THE I-72 CORRIDOR LATER THIS EVENING. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY...WITH MOST MODEL SOLUTIONS SUGGESTING THE GREATEST AREAL COVERAGE OF PRECIP ACROSS THE NORTHERN HALF OF THE KILX CWA. HRRR IS SHOWING WIDELY SCATTERED STORMS DEVELOPING OVER THE NEXT COUPLE OF HOURS...WITH THE CONVECTION BECOMING MORE WIDESPREAD AFTER SUNSET AS A WEAK LOW-LEVEL JET DEVELOPS. HAVE ADJUSTED RAIN CHANCES ACCORDINGLY...WITH LIKELY POPS ALONG/NORTH OF I-72 TAPERING DOWN TO JUST SLIGHT CHANCE ALONG/SOUTH OF I-70. .LONG TERM...(TUESDAY THROUGH MONDAY) ISSUED AT 245 PM CDT MON MAY 4 2015 AN UPPER LEVEL RIDGE IS EXPECTED TO AMPLIFY OVER THE CENTER OF THE NATION STARTING ON TUESDAY WHICH SHOULD PUSH THE BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS NORTH OF THE FORECAST AREA...AT LEAST INTO THURSDAY. SHORTWAVE ENERGY IS THEN FORECAST TO EJECTS NORTH OUT OF THE SOUTHERN PLAINS AND BRING ABOUT A CHANCE FOR MORE SHOWERS AND THUNDERSTORMS...ESPECIALLY ACROSS OUR WEST...THURSDAY NIGHT INTO FRIDAY. A MORE POTENT 500 MB TROF IS THEN FORECAST TO SLOWLY TRACK OUT OF THE ROCKIES DURING THE WEEKEND BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. MOST MODELS TRACK THIS LOW NORTH-NORTHEAST ON SUNDAY SUGGESTING THE MORE SIGNIFICANT LIFT TO REMAIN WEST OF OUR AREA UNTIL LATE SUNDAY OR MONDAY OF NEXT WEEK WHEN THE SYSTEM WILL SWING A COLD FRONT THROUGH CENTRAL ILLINOIS. UNTIL THEN...WARM TEMPERATURES TO PREVAIL WITH THE SHOWER AND STORM CHANCES ACROSS THE FAR NORTH TOMORROW AS THE FRONT RETREATS BACK TO THE NORTH...AND THEN RAIN CHANCES RETURN LATE THU INTO FRIDAY AND HOLDS THROUGH EARLY NEXT WEEK BEFORE WE FINALLY GET A CHANGE IN AIR MASS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 650 PM CDT MON MAY 4 2015 SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND TRACK ACROSS CENTRAL ILLINOIS FOR MUCH OF THE NIGHT IN THE VICINITY OF A STALLED W-E ORIENTED FRONTAL BOUNDARY. BASED ON THE EXPECTED POSITION OF THE FRONT, KPIA, KBMI, AND KCMI ARE THE MOST LIKELY OF THE LOCAL TAF SITES TO BE IMPACTED. EXPECT MOSTLY VARIABLE WINDS THROUGH THE NIGHT IN THE VICINITY OF THE FRONT, WITH WINDS TRENDING SOUTHERLY TUESDAY AS THE FRONT PUSHES BACK NORTHWARD, ALSO TAKING THE BULK OF THE PRECIPITATION RISK WITH IT. PREDOMINANTLY VFR CONDITIONS ARE EXPECTED, ALTHOUGH PERIODS OF MVFR CONDITIONS WILL DEVELOP TONIGHT IN AREAS THAT RECEIVE STEADIER RAINFALL. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BAK SHORT TERM...BARNES LONG TERM...SMITH AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
654 PM CDT MON MAY 4 2015 .SHORT TERM...(TONIGHT) ISSUED AT 245 PM CDT MON MAY 4 2015 FRONTAL BOUNDARY EXTENDING FROM SOUTHERN LAKE MICHIGAN TO NORTHERN KANSAS WILL SINK SOUTHWARD...EVENTUALLY STALLING NEAR THE I-72 CORRIDOR LATER THIS EVENING. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY...WITH MOST MODEL SOLUTIONS SUGGESTING THE GREATEST AREAL COVERAGE OF PRECIP ACROSS THE NORTHERN HALF OF THE KILX CWA. HRRR IS SHOWING WIDELY SCATTERED STORMS DEVELOPING OVER THE NEXT COUPLE OF HOURS...WITH THE CONVECTION BECOMING MORE WIDESPREAD AFTER SUNSET AS A WEAK LOW-LEVEL JET DEVELOPS. HAVE ADJUSTED RAIN CHANCES ACCORDINGLY...WITH LIKELY POPS ALONG/NORTH OF I-72 TAPERING DOWN TO JUST SLIGHT CHANCE ALONG/SOUTH OF I-70. .LONG TERM...(TUESDAY THROUGH MONDAY) ISSUED AT 245 PM CDT MON MAY 4 2015 AN UPPER LEVEL RIDGE IS EXPECTED TO AMPLIFY OVER THE CENTER OF THE NATION STARTING ON TUESDAY WHICH SHOULD PUSH THE BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS NORTH OF THE FORECAST AREA...AT LEAST INTO THURSDAY. SHORTWAVE ENERGY IS THEN FORECAST TO EJECTS NORTH OUT OF THE SOUTHERN PLAINS AND BRING ABOUT A CHANCE FOR MORE SHOWERS AND THUNDERSTORMS...ESPECIALLY ACROSS OUR WEST...THURSDAY NIGHT INTO FRIDAY. A MORE POTENT 500 MB TROF IS THEN FORECAST TO SLOWLY TRACK OUT OF THE ROCKIES DURING THE WEEKEND BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. MOST MODELS TRACK THIS LOW NORTH-NORTHEAST ON SUNDAY SUGGESTING THE MORE SIGNIFICANT LIFT TO REMAIN WEST OF OUR AREA UNTIL LATE SUNDAY OR MONDAY OF NEXT WEEK WHEN THE SYSTEM WILL SWING A COLD FRONT THROUGH CENTRAL ILLINOIS. UNTIL THEN...WARM TEMPERATURES TO PREVAIL WITH THE SHOWER AND STORM CHANCES ACROSS THE FAR NORTH TOMORROW AS THE FRONT RETREATS BACK TO THE NORTH...AND THEN RAIN CHANCES RETURN LATE THU INTO FRIDAY AND HOLDS THROUGH EARLY NEXT WEEK BEFORE WE FINALLY GET A CHANGE IN AIR MASS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 650 PM CDT MON MAY 4 2015 SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND TRACK ACROSS CENTRAL ILLINOIS FOR MUCH OF THE NIGHT IN THE VICINITY OF A STALLED W-E ORIENTED FRONTAL BOUNDARY. BASED ON THE EXPECTED POSITION OF THE FRONT, KPIA, KBMI, AND KCMI ARE THE MOST LIKELY OF THE LOCAL TAF SITES TO BE IMPACTED. EXPECT MOSTLY VARIABLE WINDS THROUGH THE NIGHT IN THE VICINITY OF THE FRONT, WITH WINDS TRENDING SOUTHERLY TUESDAY AS THE FRONT PUSHES BACK NORTHWARD, ALSO TAKING THE BULK OF THE PRECIPITATION RISK WITH IT. PREDOMINANTLY VFR CONDITIONS ARE EXPECTED, ALTHOUGH PERIODS OF MVFR CONDITIONS WILL DEVELOP TONIGHT IN AREAS THAT RECEIVE STEADIER RAINFALL. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARNES LONG TERM...SMITH AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
256 PM CDT SUN MAY 3 2015 .SHORT TERM...(TONIGHT) ISSUED AT 250 PM CDT SUN MAY 3 2015 A WEAKENING SHORT WAVE OVER EASTERN IA AND NW IL BY MS RIVER WILL LIFT INTO SE WI BY SUNSET AND KEEP BEST CHANCES OF SHOWERS AND THUNDERSTORMS NORTH OF I-80 THROUGH SUNSET WITH JUST ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS OVER THE IL RIVER VALLEY. CHANCES OF SHOWERS AND THUNDERSTORMS WILL INCREASE DURING THE NIGHT ESPECIALLY OVERNIGHT OVER THE IL RIVER VALLEY WITH SLIGHT CHANCES EXTENDING AS FAR SE AT CHARLESTON/MATTOON BY SUNRISE MONDAY AS YET ANOTHER SHORT WAVE OVER EASTERN NEBRASKA TRACKS EAST TOWARD THE IA/IL BORDER BY 12Z/7 AM MONDAY. SPC KEEPS RISK OF SEVERE STORMS NW OF IL OVER NORTHERN IA, SE MN AND INTO CENTRAL WI THROUGH DAYBREAK MONDAY WHERE BETTER FORCING WILL BE AS COLD FRONT PUSHES SE INTO CENTRAL PARTS OF WI/IA BY SUNRISE MONDAY. STAYED CLOSE TO MET/MAV GUIDANCE LOWS TONIGHT IN THE UPPER 50S AND LOWER 60S WITH COOLEST READINGS IN EASTERN/SE IL. BREEZY SSW WINDS 15-25 MPH THIS AFTERNOON WILL DIMINISH SOUTH 7-14 MPH AFTER SUNSET. && .LONG TERM...(MONDAY THROUGH SUNDAY) ISSUED AT 250 PM CDT SUN MAY 3 2015 MAIN FORECAST CHALLENGE WILL BE POSITION OF FRONTAL BOUNDARY AND HIGHER RAIN CHANCES LATER TONIGHT THRU MONDAY NIGHT. REMNANTS OF TODAY`S MCV SHOULD PUSH OFF TO OUR NORTHEAST PUSHING THE SHOWERS EVEN FURTHER AWAY FROM THE FORECAST AREA THIS EVENING. WEAK UPPER LEVEL DISTURBANCE OVER THE MISSOURI VALLEY HAS A FEW SHOWERS ASSOCIATED WITH IT BUT THE LAST FEW RUNS OF THE RAP AND HRRR HAVE BACKED OFF SOME ON ANY ORGANIZED SHOWER AND THUNDERSTORM THREAT WITH THAT FEATURE. IT STILL APPEARS OUR MAIN THREAT WILL COME LATER TONIGHT AND THRU THE MORNING HOURS OF MONDAY WITH REDEVELOPMENT TAKING PLACE LATER TOMORROW AFTERNOON INTO THE EVENING RIGHT ALONG THE STALLED FRONTAL BOUNDARY. HAVE TRENDED MORE TOWARDS THE HIGH RESOLUTION MODEL SOLUTIONS FROM THE NSSL-ARW AND 4KM NAM-WRF WITH RESPECT TO FRONTAL POSITION ON MONDAY AND ASSOCIATED PRECIP CHANCES ALONG IT. THE HIGHER POPS WILL REMAIN ACROSS THE NORTHERN HALF OF THE FORECAST AREA BEFORE THE BOUNDARY SHIFTS BACK NORTH LATE TUESDAY INTO WEDNESDAY AS UPPER LEVEL RIDGING BUILDS ACROSS THE REGION. SEVERE THREAT WILL BE TIED TO THE POSITION OF THE BOUNDARY MONDAY AFTERNOON AND EVENING WITH THE NAM-WRF INDICATING A 40-45 KT LOW LEVEL JET SETTING UP TONIGHT FROM NORTHERN MISSOURI NORTHEAST INTO NORTHERN IL WITH THE STRONGER 850 MB THETA-E ADVECTION AND MOISTURE TRANSPORT LOCATED FROM NORTHEAST MISSOURI INTO NORTHERN IL. STORMS SHOULD DEVELOP WELL OUT TO OUR WEST AND NORTHWEST LATER THIS EVENING AND THEN TRANSLATE EAST AND SOUTHEAST INTO OUR NORTHERN AREAS BY LATE EVENING OR DURING THE EARLY MORNING HOURS OF MONDAY. IF A DECENT COLD POOL DEVELOPS LATER TONIGHT...THOSE STORMS MAY TRACK FURTHER SOUTH AND AFFECT THE POSITION OF THE SYNOPTIC SCALE BOUNDARY IN OUR AREA ON MONDAY/MONDAY EVENING. WITH THE WEST TO EAST BOUNDARY LOCATED ACROSS A PORTION OF THE FORECAST AREA MONDAY AFTERNOON AND EVENING...LOOK FOR STORMS TO FIRE AGAIN ALONG THE INSTABILITY AXIS WHICH SHOULD BE ALIGNED FROM NORTHERN MISSOURI INTO WEST CENTRAL IL BY MID AFTERNOON. MIXED LAYER CAPES OF 1500-2000 J/KG AND EFFECTIVE SHEAR VALUES OF 25 KTS SHOULD PROMOTE STORM ORGANIZATION WITH ISOLATED STRONG WIND GUSTS AND HAIL POSSIBLE WITH 700-500 MB LAPSE RATES OF 6.5-7 DEG/C DEPICTED ON SOUNDINGS TOMORROW AFTERNOON ACROSS THE NORTH. SCATTERED STORMS SHOULD CONTINUE MONDAY NIGHT AND THEN BEGIN TO EDGE NORTHWARD BY TUESDAY AS THE UPPER LEVEL RIDGING BEGINS TO AMPLIFY ACROSS THE MIDWEST. ONCE THE 500 MB RIDGE BUILDS OVER THE AREA ON TUESDAY...SHOWER AND THUNDERSTORM CHANCES WILL SHIFT NORTH CLOSER TO THE RETREATING SURFACE BOUNDARY. OUR NEXT THREAT WILL BE ASSOCIATED WITH A LEAD SHORTWAVE TROF THAT IS FORECAST TO EJECT NORTHEAST INTO THE SOUTHERN AND CENTRAL PLAINS ON THURSDAY WITH THE HIGHEST POPS...AT LEAST INITIALLY...ACROSS THE WEST AS MODELS SUGGEST MOST OF THE STRONGER LIFT AND INSTABILITY WILL SHIFT MORE NORTH THAN EAST. HOWEVER...OUR AREA WILL BE UNDER A SOUTHWEST FLOW ALOFT LATE IN THE WEEK AND INTO NEXT WEEKEND WITH A DEEPER UPPER LEVEL LOW FORECAST BY MEDIUM RANGE MODELS TO PUSH OUT OF THE PLAINS AND INTO THE MIDWEST BY LATE IN THE WEEKEND. UNFORTUNATELY...THIS TYPE OF A PATTERN THIS TIME OF YEAR BRINGS DAILY CHANCES FOR SHOWERS AND STORMS BUT AT LEAST THE TEMPERATURES WILL REMAIN ABOVE NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1255 PM CDT SUN MAY 3 2015 VFR CONDITIONS GENERALLY EXPECTED TO CONTINUE ACROSS THE CENTRAL IL AIRPORTS NEXT 24 HOURS THROUGH 18Z/1 PM MONDAY DUE TO UPPER LEVEL RIDGE INTO THE MID MS RIVER VALLEY. SCATTERED TO BROKEN MID/HIGH CLOUDS TO OCCUR AT TIMES THROUGH MONDAY MORNING. FEW TO SCATTERED CUMULUS CLOUDS 5-8 KFT APPEARING THIS AFTERNOON AND COULD GO BROKEN AT TIMES TONIGHT INTO MID MONDAY MORNING. VCSH AT PIA THIS AFTERNOON WHILE BRUNT OF SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON STAY NORTH OF I-80 AS WEAKENING SHORT WAVE IN EASTERN IA LIFT ACROSS NORTHERN IL AND SE WI THROUGH SUNSET. CARRIED VCSH SHOWERS AT PIA AND BMI THIS EVENING THOUGH BEST CHANCES AGAIN TO THE NW PER HIGH RES MODELS LIKE HRRR AND RAP. A LITTLE BETTER CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS FROM 09Z-15Z ESPECIALLY AT NORTHERN AIRPORTS OF BMI AND PIA AS ANOTHER SHORT WAVE TRACKS EASTWARD FROM IA INTO THE IL RIVER VALLEY BY 15Z/MON. BREEZY SSW WINDS 13-18 KTS WITH GUSTS OF 20-27 KTS THIS AFTERNOON TO DIMINISH SOUTH CLOSER TO 10 KTS AFTER SUNSET AND BECOME SW 10-13 KTS WITH GUSTS 15-20 KTS AFTER 15Z/MONDAY. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...07 LONG TERM...SMITH AVIATION...07
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1256 PM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 1045 AM CDT SUN MAY 3 2015 FORECAST WAS UPDATED TWICE THIS MORNING TO ADDRESS THE SMALL CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS OVER NORTHERN COUNTIES TODAY AND HANDLING CLOUD COVER. HAVE 20% CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON MAINLY NW OF I-55 WITH 30% CHANCE FAR NORTHERN COUNTIES OF KNOX, STARK AND MARSHALL COUNTIES. SCATTERED SHOWERS OVER SE IA INTO NW IL JUST NW OF ILX CWA WAS TRACKING ENE AHEAD OF ANOTHER WEAK SHORT WAVE OVER CENTRAL IA THAT WILL WEAKEN A LIFT INTO NE IL THIS AFTERNOON KEEPING BETTER CHANCES OF CONVECTION NORTH OF CENTRAL IL REST OF TODAY. IL RIVER VALLEY WILL BE ON SOUTHERN EDGE OF THIS WEATHER SYSTEM TO HAVE SMALL CHANCES OF CONVECTION THERE. TEMPS AT 1030 AM HAVE WARMED INTO THE UPPER 60S TO MID 70S AND WARM HIGHS IN THE LOWER 80S EXPECTED BY 4 PM TODAY ACROSS MUCH OF THE AREA. BREEZY SOUTHWEST WINDS OF 15 TO 25 MPH AND PARTLY TO MOSTLY SUNNY SKIES. && .SHORT TERM...(TODAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 SURFACE TROUGH AND FRONTAL BOUNDARY REMAIN WELL OFF TO THE NORTHWEST THIS MORNING...DRAPED FROM SD NORTHEAST THROUGH MN. THIS WILL BECOME THE FOCUS FOR CONVECTIVE ACTIVITY LATER TODAY AS IT MOVES CLOSER TO CENTRAL IL IN THE LATE AFTERNOON. THIS MORNING A SHORTWAVE EVIDENT ON WATER VAPOR IMAGERY OVER CENTRAL IL CONTINUES TO PRODUCE A FEW SHOWERS...EXPECTED TO MOVE EASTWARD AND DISSIPATE LATER THIS MORNING IN EAST CENTRAL IL ACCORDING TO LATEST HRRR RUN. ANOTHER SHORTWAVE OVER WEST IA IS EXPECTED TO TRACK ENE AND PASS BY THE CENTRAL IL FORECAST AREA TO THE NORTH. WITH GENERAL SUBSIDENCE INDICATED ACROSS THE AREA...HAVE KEPT THE FORECAST DRY LATE MORNING THROUGH LATE AFTERNOON/EARLY EVENING ONCE THE INITIAL ROUND OF MORNING SHOWERS PASSES THROUGH. LOW LEVEL SOUTHERLY FLOW WILL KEEP THE WARMING TREND GOING FOR TODAY WITH HIGHS REACHING AROUND 80 DEGREES. FORECAST SOUNDINGS INDICATE BOUNDARY LAYER MOMENTUM CAPABLE OF PRODUCING GUSTS 20-25 MPH FROM I-70 NORTHWARD...WITH SUSTAINED SOUTHERLY WINDS 12-18 MPH. .LONG TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 NOT A LOT OF CHANGES IN THE FORECAST. MAJORITY OF FORECAST REVOLVES AROUND A SLOWING/STALLED FRONTAL BOUNDARY ACROSS THE REGION FOR TONIGHT AND THROUGH TOMORROW BEFORE BEING EDGED TO THE NORTH BEFORE ANOTHER SYSTEM SPINS UP OVER THE PLAINS AND MOVES INTO THE REGION. FOR TONIGHT, THE FRONTAL BOUNDARY SETTLING IN JUST TO THE NORTHWEST WILL PROVIDE AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS FOR THE AREA...SETTLING INTO THE NORTHERN HALF OF THE STATE AND BECOMING HUNG UP IN QUASI ZONAL FLOW ALOFT. BEST CHANCES FOR PRECIP REMAIN IN THE NORTHERN HALF OF THE STATE PROVIDING SOME FOCUS FOR STORM DEVELOPMENT. MODELS HAVE TRENDED A LITTLE MORE SCATTERED IN THE QPF FIELDS, ALTHOUGH THE NORTHERN HALF OF THE STATE STILL SEEMS PRIMED FOR THE BEST CHANCES OF PRECIP THROUGH MONDAY NIGHT, SPECIFICALLY THE AREAS WHERE THE BOUNDARY STALLS. SPC HAS KEPT THE NORTHERN HALF OF THE CWA IN A MARGINAL RISK FOR STORMS INVOF THE BOUNDARY ON MONDAY. CLUSTERS OF STORMS NEAR A WEAK BOUNDARY LOOKING BORDERLINE AT THIS POINT, BUT IN AN AREA OF CONTINUING WARM AIR ADVECTION PROVIDING POTENTIAL INSTABILITY JUST SOUTH OF THE BOUNDARY THAT WILL SLOWLY BE SETTLING SOUTH INTO THE WARMER AND MORE BUOYANT AIR. A RIDGE BEGINS TO BUILD INTO THE MIDWEST FROM THE SOUTHEAST...WITH ENOUGH SUBSIDENCE IN THE REGION OF THE RIDGE AXIS TO ERODE SHOWER CHANCES AT LEAST TUES NIGHT THROUGH WED NIGHT. ANOTHER PATTERN SHIFT TAKES HOLD FOR THE LATER HALF OF THE WEEK, SETTING UP MORE OF A SOUTHWESTERLY FLOW AND AN ACTIVE WEATHER PATTERN AGAIN AS WAVES CONTINUE TO RIPPLE AROUND THE SWRN LOW AND INTO THE MIDWEST. A RATHER WET FORECAST OVERALL, WITH SEVERAL DIFFERENT PATTERNS ESTABLISHING THEMSELVES...AND KEEPING SHOWERS AND THUNDERSTORMS IN THE OUTLOOK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1255 PM CDT SUN MAY 3 2015 VFR CONDITIONS GENERALLY EXPECTED TO CONTINUE ACROSS THE CENTRAL IL AIRPORTS NEXT 24 HOURS THROUGH 18Z/1 PM MONDAY DUE TO UPPER LEVEL RIDGE INTO THE MID MS RIVER VALLEY. SCATTERED TO BROKEN MID/HIGH CLOUDS TO OCCUR AT TIMES THROUGH MONDAY MORNING. FEW TO SCATTERED CUMULUS CLOUDS 5-8 KFT APPEARING THIS AFTERNOON AND COULD GO BROKEN AT TIMES TONIGHT INTO MID MONDAY MORNING. VCSH AT PIA THIS AFTERNOON WHILE BRUNT OF SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON STAY NORTH OF I-80 AS WEAKENING SHORT WAVE IN EASTERN IA LIFT ACROSS NORTHERN IL AND SE WI THROUGH SUNSET. CARRIED VCSH SHOWERS AT PIA AND BMI THIS EVENING THOUGH BEST CHANCES AGAIN TO THE NW PER HIGH RES MODELS LIKE HRRR AND RAP. A LITTLE BETTER CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS FROM 09Z-15Z ESPECIALLY AT NORTHERN AIRPORTS OF BMI AND PIA AS ANOTHER SHORT WAVE TRACKS EASTWARD FROM IA INTO THE IL RIVER VALLEY BY 15Z/MON. BREEZY SSW WINDS 13-18 KTS WITH GUSTS OF 20-27 KTS THIS AFTERNOON TO DIMINISH SOUTH CLOSER TO 10 KTS AFTER SUNSET AND BECOME SW 10-13 KTS WITH GUSTS 15-20 KTS AFTER 15Z/MONDAY. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...07 SHORT TERM...ONTON LONG TERM...HJS AVIATION...07
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1044 AM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 1045 AM CDT SUN MAY 3 2015 FORECAST WAS UPDATED TWICE THIS MORNING TO ADDRESS THE SMALL CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS OVER NORTHERN COUNTIES TODAY AND HANDLING CLOUD COVER. HAVE 20% CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON MAINLY NW OF I-55 WITH 30% CHANCE FAR NORTHERN COUNTIES OF KNOX, STARK AND MARSHALL COUNTIES. SCATTERED SHOWERS OVER SE IA INTO NW IL JUST NW OF ILX CWA WAS TRACKING ENE AHEAD OF ANOTHER WEAK SHORT WAVE OVER CENTRAL IA THAT WILL WEAKEN A LIFT INTO NE IL THIS AFTERNOON KEEPING BETTER CHANCES OF CONVECTION NORTH OF CENTRAL IL REST OF TODAY. IL RIVER VALLEY WILL BE ON SOUTHERN EDGE OF THIS WEATHER SYSTEM TO HAVE SMALL CHANCES OF CONVECTION THERE. TEMPS AT 1030 AM HAVE WARMED INTO THE UPPER 60S TO MID 70S AND WARM HIGHS IN THE LOWER 80S EXPECTED BY 4 PM TODAY ACROSS MUCH OF THE AREA. BREEZY SOUTHWEST WINDS OF 15 TO 25 MPH AND PARTLY TO MOSTLY SUNNY SKIES. && .SHORT TERM...(TODAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 SURFACE TROUGH AND FRONTAL BOUNDARY REMAIN WELL OFF TO THE NORTHWEST THIS MORNING...DRAPED FROM SD NORTHEAST THROUGH MN. THIS WILL BECOME THE FOCUS FOR CONVECTIVE ACTIVITY LATER TODAY AS IT MOVES CLOSER TO CENTRAL IL IN THE LATE AFTERNOON. THIS MORNING A SHORTWAVE EVIDENT ON WATER VAPOR IMAGERY OVER CENTRAL IL CONTINUES TO PRODUCE A FEW SHOWERS...EXPECTED TO MOVE EASTWARD AND DISSIPATE LATER THIS MORNING IN EAST CENTRAL IL ACCORDING TO LATEST HRRR RUN. ANOTHER SHORTWAVE OVER WEST IA IS EXPECTED TO TRACK ENE AND PASS BY THE CENTRAL IL FORECAST AREA TO THE NORTH. WITH GENERAL SUBSIDENCE INDICATED ACROSS THE AREA...HAVE KEPT THE FORECAST DRY LATE MORNING THROUGH LATE AFTERNOON/EARLY EVENING ONCE THE INITIAL ROUND OF MORNING SHOWERS PASSES THROUGH. LOW LEVEL SOUTHERLY FLOW WILL KEEP THE WARMING TREND GOING FOR TODAY WITH HIGHS REACHING AROUND 80 DEGREES. FORECAST SOUNDINGS INDICATE BOUNDARY LAYER MOMENTUM CAPABLE OF PRODUCING GUSTS 20-25 MPH FROM I-70 NORTHWARD...WITH SUSTAINED SOUTHERLY WINDS 12-18 MPH. .LONG TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 NOT A LOT OF CHANGES IN THE FORECAST. MAJORITY OF FORECAST REVOLVES AROUND A SLOWING/STALLED FRONTAL BOUNDARY ACROSS THE REGION FOR TONIGHT AND THROUGH TOMORROW BEFORE BEING EDGED TO THE NORTH BEFORE ANOTHER SYSTEM SPINS UP OVER THE PLAINS AND MOVES INTO THE REGION. FOR TONIGHT, THE FRONTAL BOUNDARY SETTLING IN JUST TO THE NORTHWEST WILL PROVIDE AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS FOR THE AREA...SETTLING INTO THE NORTHERN HALF OF THE STATE AND BECOMING HUNG UP IN QUASI ZONAL FLOW ALOFT. BEST CHANCES FOR PRECIP REMAIN IN THE NORTHERN HALF OF THE STATE PROVIDING SOME FOCUS FOR STORM DEVELOPMENT. MODELS HAVE TRENDED A LITTLE MORE SCATTERED IN THE QPF FIELDS, ALTHOUGH THE NORTHERN HALF OF THE STATE STILL SEEMS PRIMED FOR THE BEST CHANCES OF PRECIP THROUGH MONDAY NIGHT, SPECIFICALLY THE AREAS WHERE THE BOUNDARY STALLS. SPC HAS KEPT THE NORTHERN HALF OF THE CWA IN A MARGINAL RISK FOR STORMS INVOF THE BOUNDARY ON MONDAY. CLUSTERS OF STORMS NEAR A WEAK BOUNDARY LOOKING BORDERLINE AT THIS POINT, BUT IN AN AREA OF CONTINUING WARM AIR ADVECTION PROVIDING POTENTIAL INSTABILITY JUST SOUTH OF THE BOUNDARY THAT WILL SLOWLY BE SETTLING SOUTH INTO THE WARMER AND MORE BUOYANT AIR. A RIDGE BEGINS TO BUILD INTO THE MIDWEST FROM THE SOUTHEAST...WITH ENOUGH SUBSIDENCE IN THE REGION OF THE RIDGE AXIS TO ERODE SHOWER CHANCES AT LEAST TUES NIGHT THROUGH WED NIGHT. ANOTHER PATTERN SHIFT TAKES HOLD FOR THE LATER HALF OF THE WEEK, SETTING UP MORE OF A SOUTHWESTERLY FLOW AND AN ACTIVE WEATHER PATTERN AGAIN AS WAVES CONTINUE TO RIPPLE AROUND THE SWRN LOW AND INTO THE MIDWEST. A RATHER WET FORECAST OVERALL, WITH SEVERAL DIFFERENT PATTERNS ESTABLISHING THEMSELVES...AND KEEPING SHOWERS AND THUNDERSTORMS IN THE OUTLOOK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 656 AM CDT SUN MAY 3 2015 VFR CONDITIONS AND LIGHT SOUTHERLY WINDS ACROSS CENTRAL IL THIS MORNING WITH ISOLATED -SHRA THROUGH MORNING. PARTIAL CLEARING EXPECTED LATE MORNING THROUGH AFTERNOON WITH SSW WINDS INCREASING TO AROUND 15 KTS WITH GUSTS 20-25 KTS. A FRONTAL BOUNDARY APPROACHING FROM THE NORTHWEST OVERNIGHT EXPECTED TO SPREAD SCT SHRA/ISOLD TSRA INTO CENTRAL IL AFTER 00Z. INCLUDED LOWER VFR CEILINGS AND VCSH IN TAFS FROM KSPI-KBMI NORTHWESTWARD BEFORE 12Z...HOWEVER KDEC-KCMI SOUTHEASTWARD NOT LIKELY TO BE AFFECTED BEFORE 12Z. ISOLD MVFR CIGS/VSBYS POSSIBLE WITH STRONGER STORMS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...07 SHORT TERM...ONTON LONG TERM...HJS AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
656 AM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 SURFACE TROUGH AND FRONTAL BOUNDARY REMAIN WELL OFF TO THE NORTHWEST THIS MORNING...DRAPED FROM SD NORTHEAST THROUGH MN. THIS WILL BECOME THE FOCUS FOR CONVECTIVE ACTIVITY LATER TODAY AS IT MOVES CLOSER TO CENTRAL IL IN THE LATE AFTERNOON. THIS MORNING A SHORTWAVE EVIDENT ON WATER VAPOR IMAGERY OVER CENTRAL IL CONTINUES TO PRODUCE A FEW SHOWERS...EXPECTED TO MOVE EASTWARD AND DISSIPATE LATER THIS MORNING IN EAST CENTRAL IL ACCORDING TO LATEST HRRR RUN. ANOTHER SHORTWAVE OVER WEST IA IS EXPECTED TO TRACK ENE AND PASS BY THE CENTRAL IL FORECAST AREA TO THE NORTH. WITH GENERAL SUBSIDENCE INDICATED ACROSS THE AREA...HAVE KEPT THE FORECAST DRY LATE MORNING THROUGH LATE AFTERNOON/EARLY EVENING ONCE THE INITIAL ROUND OF MORNING SHOWERS PASSES THROUGH. LOW LEVEL SOUTHERLY FLOW WILL KEEP THE WARMING TREND GOING FOR TODAY WITH HIGHS REACHING AROUND 80 DEGREES. FORECAST SOUNDINGS INDICATE BOUNDARY LAYER MOMENTUM CAPABLE OF PRODUCING GUSTS 20-25 MPH FROM I-70 NORTHWARD...WITH SUSTAINED SOUTHERLY WINDS 12-18 MPH. .LONG TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 NOT A LOT OF CHANGES IN THE FORECAST. MAJORITY OF FORECAST REVOLVES AROUND A SLOWING/STALLED FRONTAL BOUNDARY ACROSS THE REGION FOR TONIGHT AND THROUGH TOMORROW BEFORE BEING EDGED TO THE NORTH BEFORE ANOTHER SYSTEM SPINS UP OVER THE PLAINS AND MOVES INTO THE REGION. FOR TONIGHT, THE FRONTAL BOUNDARY SETTLING IN JUST TO THE NORTHWEST WILL PROVIDE AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS FOR THE AREA...SETTLING INTO THE NORTHERN HALF OF THE STATE AND BECOMING HUNG UP IN QUASI ZONAL FLOW ALOFT. BEST CHANCES FOR PRECIP REMAIN IN THE NORTHERN HALF OF THE STATE PROVIDING SOME FOCUS FOR STORM DEVELOPMENT. MODELS HAVE TRENDED A LITTLE MORE SCATTERED IN THE QPF FIELDS, ALTHOUGH THE NORTHERN HALF OF THE STATE STILL SEEMS PRIMED FOR THE BEST CHANCES OF PRECIP THROUGH MONDAY NIGHT, SPECIFICALLY THE AREAS WHERE THE BOUNDARY STALLS. SPC HAS KEPT THE NORTHERN HALF OF THE CWA IN A MARGINAL RISK FOR STORMS INVOF THE BOUNDARY ON MONDAY. CLUSTERS OF STORMS NEAR A WEAK BOUNDARY LOOKING BORDERLINE AT THIS POINT, BUT IN AN AREA OF CONTINUING WARM AIR ADVECTION PROVIDING POTENTIAL INSTABILITY JUST SOUTH OF THE BOUNDARY THAT WILL SLOWLY BE SETTLING SOUTH INTO THE WARMER AND MORE BUOYANT AIR. A RIDGE BEGINS TO BUILD INTO THE MIDWEST FROM THE SOUTHEAST...WITH ENOUGH SUBSIDENCE IN THE REGION OF THE RIDGE AXIS TO ERODE SHOWER CHANCES AT LEAST TUES NIGHT THROUGH WED NIGHT. ANOTHER PATTERN SHIFT TAKES HOLD FOR THE LATER HALF OF THE WEEK, SETTING UP MORE OF A SOUTHWESTERLY FLOW AND AN ACTIVE WEATHER PATTERN AGAIN AS WAVES CONTINUE TO RIPPLE AROUND THE SWRN LOW AND INTO THE MIDWEST. A RATHER WET FORECAST OVERALL, WITH SEVERAL DIFFERENT PATTERNS ESTABLISHING THEMSELVES...AND KEEPING SHOWERS AND THUNDERSTORMS IN THE OUTLOOK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 656 AM CDT SUN MAY 3 2015 VFR CONDITIONS AND LIGHT SOUTHERLY WINDS ACROSS CENTRAL IL THIS MORNING WITH ISOLATED -SHRA THROUGH MORNING. PARTIAL CLEARING EXPECTED LATE MORNING THROUGH AFTERNOON WITH SSW WINDS INCREASING TO AROUND 15 KTS WITH GUSTS 20-25 KTS. A FRONTAL BOUNDARY APPROACHING FROM THE NORTHWEST OVERNIGHT EXPECTED TO SPREAD SCT SHRA/ISOLD TSRA INTO CENTRAL IL AFTER 00Z. INCLUDED LOWER VFR CEILINGS AND VCSH IN TAFS FROM KSPI-KBMI NORTHWESTWARD BEFORE 12Z...HOWEVER KDEC-KCMI SOUTHEASTWARD NOT LIKELY TO BE AFFECTED BEFORE 12Z. ISOLD MVFR CIGS/VSBYS POSSIBLE WITH STRONGER STORMS. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ONTON LONG TERM...HJS AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
339 AM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 SURFACE TROUGH AND FRONTAL BOUNDARY REMAIN WELL OFF TO THE NORTHWEST THIS MORNING...DRAPED FROM SD NORTHEAST THROUGH MN. THIS WILL BECOME THE FOCUS FOR CONVECTIVE ACTIVITY LATER TODAY AS IT MOVES CLOSER TO CENTRAL IL IN THE LATE AFTERNOON. THIS MORNING A SHORTWAVE EVIDENT ON WATER VAPOR IMAGERY OVER CENTRAL IL CONTINUES TO PRODUCE A FEW SHOWERS...EXPECTED TO MOVE EASTWARD AND DISSIPATE LATER THIS MORNING IN EAST CENTRAL IL ACCORDING TO LATEST HRRR RUN. ANOTHER SHORTWAVE OVER WEST IA IS EXPECTED TO TRACK ENE AND PASS BY THE CENTRAL IL FORECAST AREA TO THE NORTH. WITH GENERAL SUBSIDENCE INDICATED ACROSS THE AREA...HAVE KEPT THE FORECAST DRY LATE MORNING THROUGH LATE AFTERNOON/EARLY EVENING ONCE THE INITIAL ROUND OF MORNING SHOWERS PASSES THROUGH. LOW LEVEL SOUTHERLY FLOW WILL KEEP THE WARMING TREND GOING FOR TODAY WITH HIGHS REACHING AROUND 80 DEGREES. FORECAST SOUNDINGS INDICATE BOUNDARY LAYER MOMENTUM CAPABLE OF PRODUCING GUSTS 20-25 MPH FROM I-70 NORTHWARD...WITH SUSTAINED SOUTHERLY WINDS 12-18 MPH. && .LONG TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 338 AM CDT SUN MAY 3 2015 NOT A LOT OF CHANGES IN THE FORECAST. MAJORITY OF FORECAST REVOLVES AROUND A SLOWING/STALLED FRONTAL BOUNDARY ACROSS THE REGION FOR TONIGHT AND THROUGH TOMORROW BEFORE BEING EDGED TO THE NORTH BEFORE ANOTHER SYSTEM SPINS UP OVER THE PLAINS AND MOVES INTO THE REGION. FOR TONIGHT, THE FRONTAL BOUNDARY SETTLING IN JUST TO THE NORTHWEST WILL PROVIDE AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS FOR THE AREA...SETTLING INTO THE NORTHERN HALF OF THE STATE AND BECOMING HUNG UP IN QUASI ZONAL FLOW ALOFT. BEST CHANCES FOR PRECIP REMAIN IN THE NORTHERN HALF OF THE STATE PROVIDING SOME FOCUS FOR STORM DEVELOPMENT. MODELS HAVE TRENDED A LITTLE MORE SCATTERED IN THE QPF FIELDS, ALTHOUGH THE NORTHERN HALF OF THE STATE STILL SEEMS PRIMED FOR THE BEST CHANCES OF PRECIP THROUGH MONDAY NIGHT, SPECIFICALLY THE AREAS WHERE THE BOUNDARY STALLS. SPC HAS KEPT THE NORTHERN HALF OF THE CWA IN A MARGINAL RISK FOR STORMS INVOF THE BOUNDARY ON MONDAY. CLUSTERS OF STORMS NEAR A WEAK BOUNDARY LOOKING BORDERLINE AT THIS POINT, BUT IN AN AREA OF CONTINUING WARM AIR ADVECTION PROVIDING POTENTIAL INSTABILITY JUST SOUTH OF THE BOUNDARY THAT WILL SLOWLY BE SETTLING SOUTH INTO THE WARMER AND MORE BUOYANT AIR. A RIDGE BEGINS TO BUILD INTO THE MIDWEST FROM THE SOUTHEAST...WITH ENOUGH SUBSIDENCE IN THE REGION OF THE RIDGE AXIS TO ERODE SHOWER CHANCES AT LEAST TUES NIGHT THROUGH WED NIGHT. ANOTHER PATTERN SHIFT TAKES HOLD FOR THE LATER HALF OF THE WEEK, SETTING UP MORE OF A SOUTHWESTERLY FLOW AND AN ACTIVE WEATHER PATTERN AGAIN AS WAVES CONTINUE TO RIPPLE AROUND THE SWRN LOW AND INTO THE MIDWEST. A RATHER WET FORECAST OVERALL, WITH SEVERAL DIFFERENT PATTERNS ESTABLISHING THEMSELVES...AND KEEPING SHOWERS AND THUNDERSTORMS IN THE OUTLOOK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1150 PM CDT SAT MAY 2 2015 ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO MOVE ACROSS THE AREA OVERNIGHT. SO WILL BE KEEPING VCSH IN OVERNIGHT FOR ALL SITES. OTHERWISE, VFR AND MID LEVEL CIGS WILL BE HAD AT ALL SITES OVERNIGHT. HRRR MODEL ENDS THE PCPN TOWARD EARLY MORNING BUT MID LEVEL CIGS CONTINUE FOR A FEW HOURS. THEN CLOUDS WILL SCATTER OUT. WILL HAVE HIGH CIRRUS WHICH WILL BE THE BLOW OFF FROM THE STORMS CURRENTLY WELL WEST OF THE AREA. NOT EXPECTING TO SEE ANY OF THE PCPN ASSOCIATED WITH THESE STORMS IN THE AREA TOMORROW, BUT MODELS ADVECT SOME REMNANTS OF THESE STORMS INTO NORTHERN IL. WINDS WILL BE SOUTH TO SOUTHWEST THROUGH THE PERIOD WITH STILL THINKING OF SOME GUSTS AROUND 22-25KTS TOMORROW LATE MORNING THROUGH AFTERNOON AFTER THE CLOUDS CLEAR AND GOOD MIXING TAKES PLACE. MAY SEE SOME LLWS TOMORROW NIGHT BUT SOME UNCERTAINTY, SO NOT GOING TO PUT IN TAFS AT THIS POINT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ONTON LONG TERM...HJS AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1150 PM CDT SAT MAY 2 2015 .UPDATE... ISSUED AT 857 PM CDT SAT MAY 2 2015 ISOLATED TO SCATTERED SHOWERS ARE MOVING INTO THE AREA FROM THE WEST AND IT APPEARS THEY WILL CONTINUE TO MOVE EAST THROUGH THE NIGHT. MODELS CONTINUE TO SHOW THIS AREA WEAKENING AS IT MOVES EAST, AND IR SATELLITE LOOP SEEMS TO SUPPORT THIS WITH CLOUD TOPS WARMING ACROSS THE WHOLE AREA OF WHERE THE SHOWERS ARE. ITS ALSO MOVING AWAY INTO A DRIER AIRMASS. HAVE TRIED TO MAKE SOME ADJUSTMENTS TO POPS FOR REMAINDER OF THE NIGHT IN THE GRIDS. OTHER PARAMETERS SHOULD BE OK OR RELATIVELY CLOSE TO CURRENT AND EXPECTED CONDITIONS REMAINDER OF THE NIGHT. OTHER SHOWERS AND THUNDERSTORMS HAVE BEEN DEVELOPING FURTHER WEST IN THE PLAINS. HRRR MODEL SHOWS THESE MAKING THEIR WAY INT WESTERN AND NORTHWESTERN IL TOMORROW MORNING. WILL BE TAKING A CLOSER LOOK AT THIS OVER THE NEXT SEVERAL HOURS. ANOTHER UPDATE MAY BE NEEDED LATER THIS EVENING BEFORE NEW FORECAST PACKAGE COMES OUT AT 4AM. UPDATE TO FORECAST WILL BE COMING SHORTLY. && .SHORT TERM...(TONIGHT) ISSUED AT 255 PM CDT SAT MAY 2 2015 A WEAK SHORT WAVE OVER WESTERN IA WILL TRACK EAST TO THE IL/IA BORDER BY MIDNIGHT AND WEAKEN AS IT MOVES ACROSS CENTRAL AND NORTHERN IL OVERNIGHT. AN AREA OF SHOWERS AND ISOLATED THUNDERSTORMS OVER NORTHERN MO AND SOUTHERN IA WILL CONTINUE TO TRACK EASTWARD INTO WEST CENTRAL IL EARLY THIS EVENING BETWEEN 6-8 PM AND INTO CENTRAL IL LATER THIS EVENING AND OVERNIGHT AS SHOWERS BECOME MORE ISOLATED. HAVE 20-30% CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS FROM I-55 NW AFTER SUNSET TONIGHT AND LINGERING ISOLATED LIGHT SHOWERS UNTIL MID SUNDAY MORNING NORTH OF I-72 UNTIL WEAKENING SHORT WAVE PASSES EAST OF IL INTO WESTERN IN BY MIDDAY SUNDAY. MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE FROM THE WEST LATE THIS AFTERNOON AND EVENING WITH SOUTHEAST IL SEEING LESS CLOUD COVER TONIGHT SINCE CLOSER TO HIGH PRESSURE RIDGE OVER SOUTHEAST STATES. LOWS TONIGHT IN THE LOW TO MID 50S WITH COOLEST READINGS NEAR WABASH RIVER WHERE LIGHTER WINDS AND LESS CLOUD COVER TONIGHT. SSW WINDS 7- 14 MPH AND GUSTS 15-20 MPH THIS AFTERNOON TO DIMINISH LESS THAN 10 MPH AFTER SUNSET AND VEER SSE. .LONG TERM...(SUNDAY THROUGH SATURDAY) ISSUED AT 255 PM CDT SAT MAY 2 2015 IOWA SHORTWAVE FORECAST BY MODELS TO TRACK ACROSS THE AREA OVERNIGHT AND INTO THE MORNING HOURS OF SUNDAY BRINGING ISOLATED SHOWERS TO PARTS OF THE FORECAST AREA. SOUNDINGS STILL SHOWING A VERY DRY PROFILE BELOW 725 MB (~8500 FEET) INTO SUNDAY MORNING BEFORE THE WAVE SHIFTS OFF TO OUR EAST DURING THE MORNING. WILL KEEP SLIGHTS GOING FOR A FEW HOURS IN THE MORNING BEFORE THE WAVE MOVES OUT OF THE AREA. OUR ATTENTION THEN TURNS TO A NORTHERN STREAM SHORTWAVE THAT WILL DRAG A COLD FRONT SOUTHEAST INTO THE LOWER GREAT LAKES LATE SUNDAY AND INTO MONDAY INCREASING THE CHANCES FOR MORE WIDESPREAD SHOWERS AND STORMS...ESPECIALLY OVER THE NORTHERN HALF OF THE FORECAST AREA WHERE THE BOUNDARY IS FORECAST TO BECOME STATIONARY. AFTER OUR SLIGHT CHANCES SUNDAY MORNING...THE REST OF THE DAY LOOKS QUIET AND WARM WITH A GUSTY SOUTH TO SOUTHWEST WIND HELPING TO PUSH AFTERNOON TEMPS INTO THE UPPER 70S TO LOWER 80S. POPS START TO RAMP UP SUNDAY NIGHT ACROSS THE FAR NORTHWEST AS THE BOUNDARY EDGES SLOWLY SOUTHEAST WITH MODELS TRENDING SLOWER WITH THE FRONTAL BOUNDARY AND QPF ALONG IT. MAY HAVE TO SLOW THE ONSET OF THE SHOWERS EVEN MORE IF THESE TRENDS CONTINUE. BETTER LOW LEVEL JET SUPPORT AND 850 MB THETA-E ADVECTION REMAINS OUT TO OUR NORTHWEST LATE SUNDAY NIGHT WITH MOST MODELS SUGGESTING THAT A CLUSTER OF STORMS...AT LEAST WHAT`S LEFT OF THEM...WILL APPROACH OUR FAR NORTHWEST COUNTIES WELL AFTER MIDNIGHT SUNDAY NIGHT. THE SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO SPREAD SLOWLY SOUTHEAST ON MONDAY AND INTO MONDAY NIGHT WITH THE HIGHER THREAT BEING AGAIN WHERE THE BOUNDARY IS EXPECTED TO BECOME STATIONARY... WHICH AT THIS TIME LOOKS TO BE NORTH OF I-72. FORECAST SOUNDINGS SHOWING MIXED LAYER CAPES OF AROUND 1500 J/KG MONDAY AFTERNOON INTO EARLY MONDAY EVENING WITH THE STRONGER 500 MB WIND FLOW TO OUR NORTH WITH 30-35 KTS FORECAST. SPC HAS A LARGE AREA OF MARGINAL RISK FOR SEVERE STORMS MONDAY AFTERNOON AND EVENING STRETCHING FROM THE SOUTHERN PLAINS UP ACROSS THE NORTHERN HALF OF OUR CWA. SEVERE PARAMETERS BORDERLINE AT THIS TIME BUT WITH THE BOUNDARY IN THE AREA AND FORECAST CONVECTIVE TEMPS AROUND 80...MULTI-CELL STORMS SHOULD DEVELOP DURING THE AFTERNOON AND CONTINUE INTO THE EVENING WITH THE POSSIBILITY FOR SOME GUSTY WINDS...HAIL AND HEAVY RAINFALL WITH SOME OF THE MORE ORGANIZED CLUSTERS OF STORMS THAT FORM ALONG THE STALLED FRONTAL BOUNDARY. MODELS SUGGEST THE BOUNDARY WILL SHIFT NORTH OF THE AREA STARTING ON TUESDAY AS UPPER LEVEL HEIGHTS BUILD IN RESPONSE TO A RATHER VIGOROUS UPPER WAVE THAT WILL BE PUSHING ACROSS THE SOUTHERN ROCKIES AND EVENTUALLY SWING NORTHEAST INTO THE PLAINS BY MID TO LATE IN THE UPCOMING WORK WEEK. WILL INDICATE A BIT OF A LULL IN THE SHOWER AND STORM CHANCES UNTIL LATE THURSDAY OR FRIDAY WHEN THE WAVE WILL APPROACH OUR AREA. TEMPERATURES LOOK TO BE ABOVE NORMAL THRU THE WORK WEEK WITH AFTERNOON HIGHS CLIMBING INTO THE UPPER 70S TO LOWER 80S...WHILE EARLY MORNING LOWS ONLY DROP OFF INTO THE UPPER 50S TO LOWER 60S TUESDAY MORNING...WITH MOST OF OUR AREA SEEING LOW TEMPERATURES IN THE LOW TO MID 60S FOR THE REMAINDER OF THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1150 PM CDT SAT MAY 2 2015 ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO MOVE ACROSS THE AREA OVERNIGHT. SO WILL BE KEEPING VCSH IN OVERNIGHT FOR ALL SITES. OTHERWISE, VFR AND MID LEVEL CIGS WILL BE HAD AT ALL SITES OVERNIGHT. HRRR MODEL ENDS THE PCPN TOWARD EARLY MORNING BUT MID LEVEL CIGS CONTINUE FOR A FEW HOURS. THEN CLOUDS WILL SCATTER OUT. WILL HAVE HIGH CIRRUS WHICH WILL BE THE BLOW OFF FROM THE STORMS CURRENTLY WELL WEST OF THE AREA. NOT EXPECTING TO SEE ANY OF THE PCPN ASSOCIATED WITH THESE STORMS IN THE AREA TOMORROW, BUT MODELS ADVECT SOME REMNANTS OF THESE STORMS INTO NORTHERN IL. WINDS WILL BE SOUTH TO SOUTHWEST THROUGH THE PERIOD WITH STILL THINKING OF SOME GUSTS AROUND 22-25KTS TOMORROW LATE MORNING THROUGH AFTERNOON AFTER THE CLOUDS CLEAR AND GOOD MIXING TAKES PLACE. MAY SEE SOME LLWS TOMORROW NIGHT BUT SOME UNCERTAINTY, SO NOT GOING TO PUT IN TAFS AT THIS POINT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AUTEN SHORT TERM...07 LONG TERM...SMITH AVIATION...AUTEN
AREA FORECAST DISCUSSION
1152 PM CDT SAT MAY 2 2015
.UPDATE... ISSUED AT 957 PM CDT SAT MAY 2 2015 UPDATE MADE TO THE FORECAST FOR THE EVENING CONCERNS PRECIP UNCERTAINTIES FOR THE OVERNIGHT. THE HI-RES MODELS ALL PICK UP ON SOME ELEVATED INSTABILITY DRIBBLING ACROSS THE FORECAST AREA TONIGHT WHILE THE OTHER MODELS KEEP US DRY. WATER VAPOR SHOWS A VORT MAX AND A SECONDARY SHORTWAVE PUSHING EAST OUT OF OMAHA WHICH THE HRRR BRINGS ACROSS IOWA THROUGH THE OVERNIGHT. CERTAINLY THE STORMS OVER EASTERN NEBRASKA HAVE HELD TOGETHER AS THEY CROSSED INTO IOWA AND ADDITIONAL SHOWERS/STORMS ARE CURRENTLY RE- DEVELOPING ACROSS OUR WESTERN FORECAST AREA. THE UPDATE BROUGHT PRECIP BACK INTO THE WEST THIS EVENING INTO THE OVERNIGHT BUT JUST HOW LONG IT WILL PERSIST IS THE QUESTION. DESPITE THE HI-RES MODELS SOLUTION...THE STORMS OUT WEST ARE DYING THE FURTHER EAST THEY COME AND WE ARE FORECAST TO LOSE AT LEAST SOME OF OUR INSTABILITY OVERNIGHT. ANY SHOWERS THAT WOULD HAPPEN WOULD BE VERY HIT OR MISS IN POCKETS OF RESIDUAL INSTABILITY WHICH ARE JUST TOO HARD TO FORECAST AND CERTAINLY NOT WORTH PAINTING SLIGHT CHANCE POPS ACROSS OUR ENTIRE FORECAST AREA...AT LEAST AT THIS POINT. IF WE SEE BETTER EVIDENCE OF MORE WIDESPREAD INSTABILITY TO COINCIDE WITH THE HRRR`S WEAK SHORTWAVE AND VORT MAX DRIFTING ACROSS THE CWA OVERNIGHT WE MAY NEED TO ADD A LITTLE MORE WIDESPREAD SLIGHT CHANCE POPS TO THE GRIDS. CERTAINLY AN INTERESTING AND NOT CLEAR CUT FORECAST TONIGHT. && .SHORT TERM /TONIGHT/... ISSUED AT 310 PM CDT SAT MAY 2 2015 AREA OF SHOWERS AND A FEW THUNDERSTORMS HAS SLOWLY PROGRESSED EASTWARD ACROSS THE SOUTHERN HALF OF IOWA TODAY. THIS ACTIVITY IS IN AN AREA OF MID LEVEL THETA-E ADVECTION AND WARM ADVECTION AHEAD OF A WEAK SHORTWAVE THAT IS QUITE EVIDENT IN THE WATER VAPOR IMAGERY. THIS ACTIVITY WILL CONTINUE TO PROGRESS EASTWARD THIS EVENING WITHOUT AND EVENTUALLY EXIT THE EAST LATER THIS EVENING AS SUBSIDENCE INCREASES FROM THE WEST BEHIND THE WAVE. OVERNIGHT WILL BE RELATIVELY QUIET WITH MODEST SOUTHERLY SURFACE WINDS AND GENERALLY CLEAR TO PARTLY CLOUDY SKIES. HAVE KEPT TEMPERATURES AT OR SLIGHTLY ABOVE GUIDANCE GIVEN THE ONGOING WARM ADVECTION OVERNIGHT AND INCREASING MOISTURE. .LONG TERM /SUNDAY THROUGH SATURDAY/... ISSUED AT 310 PM CDT SAT MAY 2 2015 ACTIVE WEATHER PATTERN SETS UP ACROSS THE REGION SUNDAY NIGHT AND LASTS THROUGHOUT MUCH OF THE WEEK. SEVERE POTENTIAL SUNDAY LATE AFTERNOON INTO THE EVENING OVER THE NORTH BUT NO OTHER CLEAR CUT TIME FRAME FOR SEVERE WEATHER THE REMAINDER OF THE WEEK. LEANED TOWARD A BLEND OF THE NAM12/ECMWF FOR TEMPS AND POPS THROUGH TUESDAY...THEN A GFS/ECMWF BLEND THROUGH THE REST OF THE WEEK. SUNDAY INTO TUESDAY...GOOD SURGE OF WAA ACROSS THE STATE WILL PUSH MAX TEMPS WELL INTO THE 80S ACROSS CENTRAL IOWA. BUMPED UP MAX TEMPS UP A COUPLE DEGREES AS WELL AS WINDS DURING THE AFTERNOON WITH THE STRONG SOUTHWEST FLOW AND MIXING TO AROUND 900MB. BOUNDARY SAGS SOUTH INTO NORTHERN IOWA SUNDAY EVENING AND HELPS WEAKEN THE CAP OVER NORTHERN IOWA PAST 22Z SUNDAY. MUCAPE INCREASES TO 1500-2200 J/KG LATE IN THE AFTERNOON INTO THE EVENING WITH DEEP LAYER SHEAR STRONG ENOUGH TO SUPPORT UPDRAFTS FOR A CONSIDERABLE TIME FRAME. LOW LEVEL SHEAR IS WEAK...SO MAINLY LOOKING AT ELEVATED HAIL OVER THE NORTHERN SECTIONS OF THE FORECAST AREA WITH A SECONDARY THREAT OF DAMAGING WINDS PER LOW VALUES OF DCAPE PRESENT. TEMPERATURES MONDAY WILL BE COOLER WITH THE BOUNDARY STALLING ACROSS CENTRAL IOWA FROM WEST TO EAST...BASICALLY ALONG INTERSTATE 80 TO HIGHWAY 30 CORRIDOR THROUGH MONDAY EVENING. THUNDERSTORMS CHANCES CONTINUED SOUTH OF THE BOUNDARY DURING THE DAY MONDAY AND BY MONDAY NIGHT INTO TUESDAY...THE WARM FRONT SURGES BACK NORTHWARD AND HAVE LIKELY POPS GOING ACROSS THE ENTIRE FORECAST AREA THROUGH TUESDAY MORNING WITH FORCING AND MOISTURE TRANSPORT INTO THE STATE DURING THIS TIME. SEVERE THREAT LOOKS MINIMAL ATTM WITH THE LACK OF SIGNIFICANT INSTABILITY AND SHEAR PRESENT. THE WARM FRONT CONTINUES TO SURGE NORTH INTO SOUTHERN MINNESOTA ON TUESDAY AND PLACES THE FORECAST AREA WELL INTO THE WARM SECTOR. THE 850MB TEMPS WARM TO +12C TO +14C AND BUMPED UP MAX TEMPS CONSIDERABLY...ESPECIALLY OVER NORTHERN IOWA FOR TUESDAY. THE ATMOSPHERE BECOMES STABILIZED BY TUESDAY NIGHT INTO WEDNESDAY...AND WENT COMPLETELY DRY ACROSS MUCH OF THE FORECAST AREA DURING THIS TIME. MODELS ARE IN GOOD AGREEMENT WITH THIS DRY PERIOD. WEDNESDAY THROUGH SATURDAY...MORE PERIODIC RAIN CHANCES DURING THIS TIME FRAME WITH THE BEST POTENTIAL LOOK TO BE LATE WEDNESDAY INTO THURSDAY AS A DECENT SHORTWAVE EJECTS OUT OF THE CENTRAL ROCKIES INTO WESTERN IOWA. AFTER THURSDAY...DEPENDING ON WHICH MODEL...THERE IS THUNDERSTORM CHANCES EACH PERIOD THROUGH NEXT WEEKEND. && .AVIATION...03/06Z ISSUED AT 1152 PM CDT SAT MAY 2 2015 INTERESTING FORECAST TONIGHT AS HI-RES MODELS HAVE PICKED UP ON MID LEVEL INSTABILITY IN RESPONSE TO A WEAK WAVE PUSHING OUT OF NEBRASKA AND ACROSS IOWA TONIGHT. THUNDERSTORMS HAVE DEVELOPED IN THIS AREA AND WILL CONTINUE TO TREK EAST IN A NARROW CORRIDOR OVERNIGHT... MAINLY AFFECTING KFOD AND KALO. AFT 21Z A FRONT WILL SLOWLY SAG SOUTH ACROSS TAF LOCATIONS BRINGING THUNDERSTORMS CHANCES INCREASING ACROSS NORTHERN TAFS BY EARLY TO MID EVENING AND APPROACHING KDSM BY 06Z. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...FAB SHORT TERM...COGIL LONG TERM...PODRAZIK AVIATION...FAB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
731 PM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 720 PM MDT MON MAY 4 2015 LATEST RADAR SHOWS THE TWO SEPARATE WAVES HAVE MERGED INTO ONE OVER THE STATIONARY FRONT. MODELS INDICATE THE FRONT WILL MOVE NORTHWARD THROUGH THE NIGHT. A CONSISTENT PLUME OF LIFT WILL REMAIN OVER THE FRONT AS IT PROGRESSES NORTHWARD. AS IT MOVES NORTHWARD LIFT DECLINES OVER THE NORTHEAST QUADRANT OF THE AREA. HAVE RAINFALL CHANCES DECLINING SOME AS A RESULT. MEANWHILE TO THE SOUTH ANOTHER WAVE WILL MOVE INTO THE AREA. MODELS DISAGREE WITH WHETHER THIS WAVE WILL REMAIN OVER THE SOUTHERN PART OF THE AREA OR MOVE NORTHWARD. AM MORE INCLINED TO BELIEVE THE WAVE WILL MOVE NORTHWARD SINCE EACH OF THESE WAVES ARE ROTATING TO THE NORTH AROUND THE UPPER LEVEL LOW TO THE WEST. DUE TO THE SLOW MOVEMENT AND EFFICIENT RAIN PROCESSES...AM EXPECTING MODERATE TO HEAVY RAINFALL...PRIMARILY WITH THE FIRST WAVE TONIGHT. UPDATE ISSUED AT 555 PM MDT MON MAY 4 2015 CURRENT RADAR SHOWS THE TWO SEPARATE WAVES OF RAINFALL MERGING INTO ONE AS OUTFLOW BOUNDARIES FROM THE SOUTHERN WAVE OVER SOUTHWEST KANSAS MERGE WITH THE NEARLY STATIONARY STORMS OVER THE FRONT. CURRENT FORECAST SEEMS TO HAVE THE GENERAL TREND OF STORM DEVELOPMENT TONIGHT HANDLED FAIRLY WELL. GENERALLY LOOKS LIKE LOCATIONS WEST OF HIGHWAY 25 WILL HAVE THE BEST SHOT AT PROLONGED RAINFALL TONIGHT AS TWO DIFFERENT WAVES MOVE OVER THAT PART OF THE AREA. DUE TO THE SLOW MOVEMENT OF THE STORMS...LESS THAN 20 MPH...FLASH FLOODING WILL BE A CONCERN THROUGH THE NIGHT. REGARDING SEVERE WEATHER...INSTABILITY DECLINES DURING THE EARLY EVENING BUT THEN RETURNS OVERNIGHT EAST OF HIGHWAY 83. THERE STRONG TO POSSIBLY SEVERE STORMS ARE POSSIBLE...ALTHOUGH DEEP LAYER SHEAR IS ONLY 25KTS WHICH IS BARELY ENOUGH TO SUPPORT SUPERCELLS. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 220 PM MDT MON MAY 4 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW DEEPENING TROUGH OVER SOUTHERN CALIFORNIA WITH SW FLOW FROM THE GULF OF ALASKA AND ACROSS THE CENTRAL/HIGH PLAINS. MOIST PLUME EXTENDS FROM THE GREAT BASIN ACROSS THE OHIO RIVER VALLEY WITH ADDITIONAL MOISTURE FEEDING IN THE PLAINS FROM THE GULF OF MEXICO. AT THE SURFACE A STATIONARY FRONT EXTENDS FROM NORTHEAST KANSAS TO SOUTHEAST COLORADO AND LIES JUST SOUTHEAST OF OUR CWA...WITH BAROCLINIC ZONE EXTENDING NORTH INTO THE SE PART OF OUR CWA. THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG THIS FRONTAL ZONE TOWARDS THE SOUTHEAST PART OF OUR CWA. THIS AFTERNOON-EVENING...ALONG THIS FRONTAL ZONE ANALYSIS INDICATES ML CAPE VALUES RANGING FROM 1500 J/KG IN THE WARM SECTOR TO 500 J/KG IN OUR SE CWA. BULK SHEER IS APPROXIMATELY 30-35KT...SO DEPENDING ON POSITION OF FRONT (CURRENTLY ADVERTISED TO SLIDE NORTH INTO OUR SOUTHEAST)...THERE IS THE POTENTIAL FOR A FEW STRONGER THUNDERSTORMS...POSSIBLY SEVERE WITH LARGE HAIL/DAMAGING WINDS MAIN THREAT. IF FRONT WERE TO LIFT NORTH AS WARM FRONT WE COULD SEE BETTER SB/ML CAPE AND THE POSSIBILITY FOR A FEW MORE ORGANIZED CELLS IN THE SOUTHEAST. ANALYSIS ALSO INDICATES PWAT VALUES ALREADY IN EXCESS OF 1" OVER OUR EAST. STORM MOTIONS WILL BE ROUGHLY TANGENTIAL/PARALLEL THIS AFTERNOON BECOMING PERPENDICULAR TO FRONTAL ZONE THIS EVENING. AS THIS TRANSITION OCCURS THERE IS THE FOR BACKBUILDING OR TRAINING AS VERY MOIST/UNSTABLE AIR IN THE WARM SECTOR FEEDS NORTH. THERE COULD BE A THREAT FOR FLASH FLOODING IF THIS SCENARIO PLAYS OUT. EITHER WAY WITH VERY MOIST AIR MASS AND INCREASING ELEVATED INSTABILITY...THUNDERSTORMS COULD BE VERY EFFICIENT RAINFALL PRODUCERS. TONIGHT-TUESDAY...UPSTREAM AREAS OF MID LEVEL VORTICITY WILL ROTATE INTO THE CWA WITH INCREASING LIFT LATE THIS EVENING INTO THE OVERNIGHT. AS TROUGH CONTINUES TO DEEPEN OVER THE SW US AND MOVE EAST WE WILL CONTINUE TO SEE VERY GOOD FORCING/MOISTURE ROTATES THROUGH THE REGION. LARGE SCALE Q VECTOR FIELDS INDICATED FORCING INCREASING THROUGH THE NIGHT AND OMEGA/MOISTURE CONVERGENCE FIELDS SHOW SUPPORT FOR INCREASING COVERAGE/COMPLEX OF SHOWERS THUNDERSTORMS. ELEVATED INSTABILITY TRANSITIONS NORTHWARD AND WEAKENS...HOWEVER THERE IS ENOUGH TO KEEP THUNDER MENTION IN PLACE THROUGH TUESDAY AFTERNOON. WHILE GUIDANCE IS IN AGREEMENT ON GENERAL LARGE SCALE PATTERN THE MAIN DIFFERENCES ARE ON TIMING OF POTENTIAL PERIODS OF HEAVIER PRECIP...WITH BEST PRECIP SIGNAL AND MOISTURE PROFILES OVERLAPPING TUESDAY MORNING THROUGH TUESDAY AFTERNOON ACROSS THE WESTERN 2/3 OF THE CWA (THOUGH ECMWF MIGHT BE A LITTLE EAST). THERE WILL BE MODERATE/ELEVATED INSTABILITY IN PLACE THROUGH THE DAY TUESDAY...SO STRONG TO SEVERE THUNDERSTORMS WILL STILL BE POSSIBLE AGAIN...THOUGH SEVERE POTENTIAL MIGHT NOT BE AS GOOD AS TODAY WITH WIDESPREAD SHOWERS AND STRATUS LIMITING SURFACE BASED PARCELS AND ANY ACTIVITY LIKELY EMBEDDED WITH OTHER SHOWER CLUSTERS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 124 PM MDT MON MAY 4 2015 MAIN TROUGH AXIS WILL LIFT NORTHEAST ACROSS THE AREA TUESDAY NIGHT WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUING. AFTER MIDNIGHT...GENERAL TREND WILL BE FOR A WEST TO EAST END OF THE PRECIPITATION AS DRY SLOT WORKS IN BEHIND THE TROUGH. AFTER A LULL WEDNESDAY MORNING...WRAPAROUND PRECIPITATION WILL MOVE IN FROM COLORADO WEDNESDAY AFTERNOON AND BECOME WIDESPREAD WEDNESDAY NIGHT. A COLD FRONT WILL ALSO MOVE THROUGH WEDNESDAY NIGHT WHICH WILL PROVIDE A FOCUS FOR THUNDERSTORMS IN THE EVENING...BUT THE POST FRONTAL ENVIRONMENT HAS ONLY LIMITED ELEVATED INSTABILITY AND EXPECT ONLY ISOLATED THUNDERSTORMS THROUGH THURSDAY MORNING. HOWEVER BY THURSDAY AFTERNOON SBCAPE INCREASES ONCE AGAIN AND A COMBINATION OF MOIST LOW LEVEL UPSLOPE AND ANOTHER SHORTWAVE TROUGH IN THE SOUTHWESTERLY FLOW ALOFT WILL RESULT IN THUNDERSTORM DEVELOPMENT IN EASTERN COLORADO WHICH WILL MOVE INTO NORTHWEST KANSAS AND SOUTHWEST NEBRASKA THURSDAY EVENING. SEVERE THREAT WILL DEPEND ON HOW MUCH INSTABILITY CAN DEVELOP AFTER A CLOUDY MORNING...BUT DEEP LAYER SHEAR WOULD BE SUPPORTIVE OF ORGANIZED UPDRAFTS THROUGH EARLY EVENING BEFORE BOUNDARY LAYER DECOUPLES WITH NOCTURNAL COOLING. OVERALL PATTERN CHANGES LITTLE ON FRIDAY ALTHOUGH MODELS SHOWING ONLY MINIMAL SBCAPE AVAILABLE SO SEVERE THREAT MAY NOT BE AS GREAT. ANOTHER STRONG UPPER LOW WILL KICK OUT OF THE DESERT SOUTHWEST ON SATURDAY WITH A NEGATIVE TILT AND PROVIDE THE SYNOPTIC SCALE FORCING FOR THUNDERSTORMS. THE PATTERN SUGGESTS A SEVERE THREAT WITH MODELS SHOWING DEEP LAYER SHEAR OF OVER 50KTS AND SUFFICIENT INSTABILITY FOR SUPERCELLS. IF CURRENT TIMING TRENDS CONTINUE WOULD EXPECT TO SEE A DRY SLOT SATURDAY NIGHT FOLLOWED BY WRAPAROUND PRECIPITATION CHANCES ON SUNDAY. THE PATTERN FINALLY CHANGES BY EARLY NEXT WEEK WITH SUBTLE SHORTWAVE RIDGING IN A ZONAL FLOW WHICH WOULD TRANSLATE TO DRY CONDITIONS AND SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 555 PM MDT MON MAY 4 2015 VFR TO LIFR CONDITIONS FOR THE TAFS. CHALLENGING SET OF TAFS DUE TO TIMING OF THE DIFFERENT WAVES OF RAINFALL...THE CEILING HEIGHTS AND VISIBILITY. IN GENERAL LOOKS LIKE KGLD WILL HAVE A BETTER CHANCE FOR RECEIVING RAINFALL THAN KMCK...ESPECIALLY PROLONGED RAINFALL. BASED TIMING OF THE STORMS FOR BOTH SITES BY TRACKING THE SPEED OF THE CURRENT STORMS. IF STORM MOVEMENT CHANGES THAT WILL AFFECT THE TIMING IN THE TAFS. BASED ON OBSERVATIONS AND MODEL SOUNDINGS...LOOKS LIKE THE SECOND WAVE OF STORMS WILL CAUSE CEILINGS TO FALL. OVERNIGHT VISIBILITIES WILL DECLINE SOME BUT THEN IMPROVE BY MID MORNING. HAVE VC FOR KMCK DUE TO UNCERTAINTY THERE WILL STILL BE RAINFALL AT THE SITE DURING THE MORNING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...024 AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
609 PM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 555 PM MDT MON MAY 4 2015 CURRENT RADAR SHOWS THE TWO SEPERATE WAVES OF RAINFALL MERGING INTO ONE AS OUTFLOW BOUNDARIES FROM THE SOUTHERN WAVE OVER SOUTHWEST KANSAS MERGE WITH THE NEARLY STATIONARY STORMS OVER THE FRONT. CURRENT FORECAST SEEMS TO HAVE THE GENERAL TREND OF STORM DEVELOPMENT TONIGHT HANDLED FAIRLY WELL. GENERALLY LOOKS LIKE LOCATIONS WEST OF HIGHWAY 25 WILL HAVE THE BEST SHOT AT PROLONGED RAINFALL TONIGHT AS TWO DIFFERENT WAVES MOVE OVER THAT PART OF THE AREA. DUE TO THE SLOW MOVEMENT OF THE STORMS...LESS THAN 20 MPH...FLASH FLOODING WILL BE A CONCERN THROUGH THE NIGHT. REGARDING SEVERE WEATHER...INSTABILITY DECLINES DURING THE EARLY EVENING BUT THEN RETURNS OVERNIGHT EAST OF HIGHWAY 83. THERE STRONG TO POSSIBLY SEVERE STORMS ARE POSSIBLE...ALTHOUGH DEEP LAYER SHEAR IS ONLY 25KTS WHICH IS BARELY ENOUGH TO SUPPORT SUPERCELLS. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 220 PM MDT MON MAY 4 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW DEEPENING TROUGH OVER SOUTHERN CALIFORNIA WITH SW FLOW FROM THE GULF OF ALASKA AND ACROSS THE CENTRAL/HIGH PLAINS. MOIST PLUME EXTENDS FROM THE GREAT BASIN ACROSS THE OHIO RIVER VALLEY WITH ADDITIONAL MOISTURE FEEDING IN THE PLAINS FROM THE GULF OF MEXICO. AT THE SURFACE A STATIONARY FRONT EXTENDS FROM NORTHEAST KANSAS TO SOUTHEAST COLORADO AND LIES JUST SOUTHEAST OF OUR CWA...WITH BAROCLINIC ZONE EXTENDING NORTH INTO THE SE PART OF OUR CWA. THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG THIS FRONTAL ZONE TOWARDS THE SOUTHEAST PART OF OUR CWA. THIS AFTERNOON-EVENING...ALONG THIS FRONTAL ZONE ANALYSIS INDICATES ML CAPE VALUES RANGING FROM 1500 J/KG IN THE WARM SECTOR TO 500 J/KG IN OUR SE CWA. BULK SHEER IS APPROXIMATELY 30-35KT...SO DEPENDING ON POSITION OF FRONT (CURRENTLY ADVERTISED TO SLIDE NORTH INTO OUR SOUTHEAST)...THERE IS THE POTENTIAL FOR A FEW STRONGER THUNDERSTORMS...POSSIBLY SEVERE WITH LARGE HAIL/DAMAGING WINDS MAIN THREAT. IF FRONT WERE TO LIFT NORTH AS WARM FRONT WE COULD SEE BETTER SB/ML CAPE AND THE POSSIBILITY FOR A FEW MORE ORGANIZED CELLS IN THE SOUTHEAST. ANALYSIS ALSO INDICATES PWAT VALUES ALREADY IN EXCESS OF 1" OVER OUR EAST. STORM MOTIONS WILL BE ROUGHLY TANGENTIAL/PARALLEL THIS AFTERNOON BECOMING PERPENDICULAR TO FRONTAL ZONE THIS EVENING. AS THIS TRANSITION OCCURS THERE IS THE FOR BACKBUILDING OR TRAINING AS VERY MOIST/UNSTABLE AIR IN THE WARM SECTOR FEEDS NORTH. THERE COULD BE A THREAT FOR FLASH FLOODING IF THIS SCENARIO PLAYS OUT. EITHER WAY WITH VERY MOIST AIR MASS AND INCREASING ELEVATED INSTABILITY...THUNDERSTORMS COULD BE VERY EFFICIENT RAINFALL PRODUCERS. TONIGHT-TUESDAY...UPSTREAM AREAS OF MID LEVEL VORTICITY WILL ROTATE INTO THE CWA WITH INCREASING LIFT LATE THIS EVENING INTO THE OVERNIGHT. AS TROUGH CONTINUES TO DEEPEN OVER THE SW US AND MOVE EAST WE WILL CONTINUE TO SEE VERY GOOD FORCING/MOISTURE ROTATES THROUGH THE REGION. LARGE SCALE Q VECTOR FIELDS INDICATED FORCING INCREASING THROUGH THE NIGHT AND OMEGA/MOISTURE CONVERGENCE FIELDS SHOW SUPPORT FOR INCREASING COVERAGE/COMPLEX OF SHOWERS THUNDERSTORMS. ELEVATED INSTABILITY TRANSITIONS NORTHWARD AND WEAKENS...HOWEVER THERE IS ENOUGH TO KEEP THUNDER MENTION IN PLACE THROUGH TUESDAY AFTERNOON. WHILE GUIDANCE IS IN AGREEMENT ON GENERAL LARGE SCALE PATTERN THE MAIN DIFFERENCES ARE ON TIMING OF POTENTIAL PERIODS OF HEAVIER PRECIP...WITH BEST PRECIP SIGNAL AND MOISTURE PROFILES OVERLAPPING TUESDAY MORNING THROUGH TUESDAY AFTERNOON ACROSS THE WESTERN 2/3 OF THE CWA (THOUGH ECMWF MIGHT BE A LITTLE EAST). THERE WILL BE MODERATE/ELEVATED INSTABILITY IN PLACE THROUGH THE DAY TUESDAY...SO STRONG TO SEVERE THUNDERSTORMS WILL STILL BE POSSIBLE AGAIN...THOUGH SEVERE POTENTIAL MIGHT NOT BE AS GOOD AS TODAY WITH WIDESPREAD SHOWERS AND STRATUS LIMITING SURFACE BASED PARCELS AND ANY ACTIVITY LIKELY EMBEDDED WITH OTHER SHOWER CLUSTERS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 124 PM MDT MON MAY 4 2015 MAIN TROUGH AXIS WILL LIFT NORTHEAST ACROSS THE AREA TUESDAY NIGHT WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUING. AFTER MIDNIGHT...GENERAL TREND WILL BE FOR A WEST TO EAST END OF THE PRECIPITATION AS DRY SLOT WORKS IN BEHIND THE TROUGH. AFTER A LULL WEDNESDAY MORNING...WRAPAROUND PRECIPITATION WILL MOVE IN FROM COLORADO WEDNESDAY AFTERNOON AND BECOME WIDESPREAD WEDNESDAY NIGHT. A COLD FRONT WILL ALSO MOVE THROUGH WEDNESDAY NIGHT WHICH WILL PROVIDE A FOCUS FOR THUNDERSTORMS IN THE EVENING...BUT THE POST FRONTAL ENVIRONMENT HAS ONLY LIMITED ELEVATED INSTABILITY AND EXPECT ONLY ISOLATED THUNDERSTORMS THROUGH THURSDAY MORNING. HOWEVER BY THURSDAY AFTERNOON SBCAPE INCREASES ONCE AGAIN AND A COMBINATION OF MOIST LOW LEVEL UPSLOPE AND ANOTHER SHORTWAVE TROUGH IN THE SOUTHWESTERLY FLOW ALOFT WILL RESULT IN THUNDERSTORM DEVELOPMENT IN EASTERN COLORADO WHICH WILL MOVE INTO NORTHWEST KANSAS AND SOUTHWEST NEBRASKA THURSDAY EVENING. SEVERE THREAT WILL DEPEND ON HOW MUCH INSTABILITY CAN DEVELOP AFTER A CLOUDY MORNING...BUT DEEP LAYER SHEAR WOULD BE SUPPORTIVE OF ORGANIZED UPDRAFTS THROUGH EARLY EVENING BEFORE BOUNDARY LAYER DECOUPLES WITH NOCTURNAL COOLING. OVERALL PATTERN CHANGES LITTLE ON FRIDAY ALTHOUGH MODELS SHOWING ONLY MINIMAL SBCAPE AVAILABLE SO SEVERE THREAT MAY NOT BE AS GREAT. ANOTHER STRONG UPPER LOW WILL KICK OUT OF THE DESERT SOUTHWEST ON SATURDAY WITH A NEGATIVE TILT AND PROVIDE THE SYNOPTIC SCALE FORCING FOR THUNDERSTORMS. THE PATTERN SUGGESTS A SEVERE THREAT WITH MODELS SHOWING DEEP LAYER SHEAR OF OVER 50KTS AND SUFFICIENT INSTABILITY FOR SUPERCELLS. IF CURRENT TIMING TRENDS CONTINUE WOULD EXPECT TO SEE A DRY SLOT SATURDAY NIGHT FOLLOWED BY WRAPAROUND PRECIPITATION CHANCES ON SUNDAY. THE PATTERN FINALLY CHANGES BY EARLY NEXT WEEK WITH SUBTLE SHORTWAVE RIDGING IN A ZONAL FLOW WHICH WOULD TRANSLATE TO DRY CONDITIONS AND SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 555 PM MDT MON MAY 4 2015 VFR TO LIFR CONDITIONS FOR THE TAFS. CHALLENGING SET OF TAFS DUE TO TIMING OF THE DIFFERENT WAVES OF RAINFALL...THE CEILING HEIGHTS AND VISIBILITY. IN GENERAL LOOKS LIKE KGLD WILL HAVE A BETTER CHANCE FOR RECEIVING RAINFALL THAN KMCK...ESPECIALLY PROLONGED RAINFALL. BASED TIMING OF THE STORMS FOR BOTH SITES BY TRACKING THE SPEED OF THE CURRENT STORMS. IF STORM MOVEMENT CHANGES THAT WILL AFFECT THE TIMING IN THE TAFS. BASED ON OBSERVATIONS AND MODEL SOUNDINGS...LOOKS LIKE THE SECOND WAVE OF STORMS WILL CAUSE CIELINGS TO FALL. OVERNIGHT VISIBILITIES WILL DECLINE SOME BUT THEN IMPROVE BY MID MORNING. HAVE VC FOR KMCK DUE TO UNCERTAINTY THERE WILL STILL BE RAINFALL AT THE SITE DURING THE MORNING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...024 AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
234 PM MDT SUN MAY 3 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 224 PM MDT SUN MAY 3 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY FLOW IN PLACE ACROSS THE PLAINS WITH A SHORTWAVE TROUGH UPSTREAM OVER THE CENTRAL ROCKIES. AT THE SURFACE A TROUGH IS CURRENTLY IN PLACE OVER THE CWA...WITH A COLD FRONT NEAR IMPERIAL NEBRASKA EXTENDING INTO NORTHEAST COLORADO. REGIONAL RADAR SHOWS SCATTERED THUNDERSTORM ACTIVITY ALREADY MOVING OFF THE HIGHER TERRAIN IN COLORADO AND MOVING OFF THE PALMER DIVIDE TOWARDS THE WESTERN PART OF OUR CWA. THIS AFTERNOON-TONIGHT...WINDOW FOR SEVERE WEATHER APPEARS TO BE MAINLY AHEAD OF COLD FRONT WHERE MODELS HAD BEEN ADVERTISING MODERATE INSTABILITY DEVELOPING BY 00Z (MAINLY EAST OF SURFACE TROUGH). SO FAR RAP ANALYSIS SHOWS ML CAPE GENERALLY AROUND 500 J/KG LIKELY DUE TO MUCH LOWER TD VALUES AHEAD OF COLD FRONT THAN PREVIOUSLY ANTICIPATED. HRRR/RAP HAVE BEEN SHOWING ISOLATED DEVELOPMENT ALONG SURFACE TROUGH AXIS WHERE CAP HAS BEEN WEAKENED. THERE IS A WINDOW FOR INCREASING SHEER AS COLD FRONT MOVES SOUTH AND DEPENDING ON STRENGTH OF UPDRAFTS WE COULD SEE SOME ORGANIZED CELLS...OTHERWISE IT APPEARS TO BE AN ENVIRONMENT FAVORING PULSE TYPE THUNDERSTORMS THROUGH MOST OF THE NIGHT. DCAPE VALUES IN EXCESS OF 1000 J/KG DO RAISE CONCERNS FOR MICROBURST POTENTIAL AHEAD OF COLD FRONT SO EVEN WEAKER UPDRAFTS COULD PRODUCE NEAR SEVERE OR SEVERE WINDS AS THEY COLLAPSE. SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE LATE THIS EVENING ALONG/NORTH OF COLD FRONT WITH INCREASING MOISTURE RETURN AND ELEVATED CAPE IN PLACE. BY LATE TONIGHT INSTABILITY BEGINS TO WANE...WHILE LARGE SCALE FORCING STARTS TO SHIFT NORTH AND EAST OF THE REGION. THIS IS WHERE MODELS DIVERGE WITH NAM CONTINUING TO INDICATE AND LULL OR DRY PERIOD WHILE ECMWF/GFS INDICATE POSSIBLE OVERRUNNING OR STRATUS/FOG/DRIZZLE DEVELOPMENT ALONG/NORTH OF THE FRONT. TOUGH CALL AND WHILE I HEDGED TOWARD THE DRY NAM AT 12Z...I COULD SEE IN THIS TYPE OF PATTERN A LIGHT PRECIP/DRIZZLE EVEN EVOLVING BY MONDAY MORNING. MONDAY...UPPER LOW OVER THE SOUTHWEST US BEGINS TO DEEPEN AND MOVE EAST WITH BETTER LARGE SCALE FORCING SPREADING OVER THE CWA BY LATE AFTERNOON. DEPENDING ON WHAT HAPPENS TO POSSIBLE STRATUS DURING THE DAY WE MAY OR MAY NOT HAVE A WINDOW FOR SEVERE THUNDERSTORMS IN THE EASTERN PART OF OUR CWA WHERE MODELS SHOW WAA AND INCREASING TDS/INSTABILITY. FURTHER NORTH AND WEST STRATUS IS MORE LIKELY TO LINGER...HOLDING TEMPS DOWN IN AND ANY INSTABILITY WOULD BE ELEVATED AND WEAKER. DEPENDING ON CHOICE IN MODEL SHOWERS/THUNDERSTORMS COULD BE POSSIBLE THROUGH THE DAY...HOWEVER BETTER CHANCES SHOULD BE TIED TO STRONGER LARGE SCALE FORCING LATER DURING THE DAY MONDAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 224 PM MDT SUN MAY 3 2015 SOUTHWEST FLOW WILL PRECEDE AN UPPER TROUGH THAT WILL AFFECT THE CENTRAL PLAINS TUESDAY THROUGH WEDNESDAY. SURFACE HIGH PRESSURE WILL SHIFT EAST ACROSS THE CENTRAL PLAINS MONDAY NIGHT AS LOW PRESSURE MOVES INTO COLORADO TUESDAY. LOW PRESSURE WILL REMAIN OVER COLORADO AND WESTERN KANSAS THROUGH WEDNESDAY. POPS WILL INCREASE FROM MONDAY EVENING TO OVERNIGHT AS BETTER DYNAMICS AND MOISTURE MOVE NORTH INTO THE FA. PLAN TO GO WITH CHANCE POPS ACROSS THE WESTERN PORTION OF THE FA DURING THE EVENING WITH LIKELY POPS OVER THE SOUTHEAST ZONES CLOSER TO THE SURFACE BOUNDARY. LIKELY POPS WILL SPREAD NORTH ACROSS THE FA OVERNIGHT AS VERY FAVORABLE MOISTURE AND LIFT MOVE INTO THE FA. LIKELY AND DEFINITE POPS WILL BE USED ACROSS THE ENTIRE FA TUESDAY AND TUESDAY EVENING AS GOOD DYNAMICS AND MOISTURE CONTINUE TO STREAM NORTHWARD ACROSS THE FA. PRECIPITABLE WATER VALUES ARE AROUND AN INCH SO WILL INCLUDE MODERATE RAIN IN THE GRIDS TUESDAY. POPS WILL START DECREASING TO CHANCE POPS AFTER 06Z WEDNESDAY AS THE UPPER TROUGH STARTS TO LIFT OUT OF THE AREA. SOME LIKELY POPS WILL STILL EXIST ACROSS THE NORTHERN FA WEDNESDAY AFTERNOON AS INSTABILITY INCREASES. MIN TEMPERATURES MONDAY NIGHT SHOULD COOL TO THE MID 40S IN EASTERN COLORADO AND THE MID 50S IN THE EASTERN FA. MIN TEMPERATURES TUESDAY NIGHT WILL RANGE FROM THE LOWER TO MID 50S. MAX TEMPERATURES TUESDAY SHOULD RANGE FROM 65 TO 70 AND 70 TO 75 WEDNESDAY. IN THE EXTENDED...(WEDNESDAY NIGHT THROUGH SUNDAY)...THE UPPER TROUGH LIFTS NORTHEAST WEDNESDAY NIGHT WITH SOUTHWEST FLOW FOLLOWING THROUGH SATURDAY. THE NEXT UPPER TROUGH MOVES INTO THE PLAINS SATURDAY NIGHT AND SUNDAY. SHORTWAVES MOVING THROUGH THE FLOW AND INCREASING DYNAMICS WITH THE NEXT TROUGH SATURDAY NIGHT AND SUNDAY WILL KEEP AT LEAST A CHANCE OF THUNDERSTORMS ACROSS THE FA EACH DAY. MIN TEMPERATURES THROUGH SATURDAY NIGHT SHOULD RANGE FROM 45 TO 55. MAX TEMPERATURES WILL GENERALLY RANGE FROM THE MID 60S TO THE MID 70S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1132 AM MDT SUN MAY 3 2015 SCATTERED THUNDERSTORMS SHOULD DEVELOP THIS AFTERNOON ALONG SURFACE TROUGH WITHIN VICINITY OF BOTH KGLD AND KMCK...WITH BETTER COVERAGE LATE AFTERNOON AND EVENING. A COLD FRONT WILL DROP SOUTH OVERNIGHT WITH INSTABILITY DECREASING LEADING TO TRANSITION TO MAINLY LIGHT SHOWERS LATE...WITH A LULL IN ACTIVITY BY MONDAY MORNING POSSIBLE. SOME GUIDANCE SHOWS LIGHT PRECIP AND LOW STRATUS DEVELOPING NORTH OF THIS FRONT AND CONTINUING TO IMPACT BOTH KGLD AND KMCK AFTER 11-13Z PERIOD THROUGH MIDDAY MONDAY. THERE IS QUITE A BIT OF SPREAD IN GUIDANCE AFTER 09Z...SO CONFIDENCE IS LOW. CONDITIONAL CLIMATOLOGY FAVORS AT LEAST IFR CIGS WITH EASTERLY FLOW/LOW LEVEL MOISTURE INCREASING NORTH OF THE FRONT. I INTRODUCED 2000-2500 CIG GROUPS FOR MONDAY MORNING AS A START AS I WOULD RATHER NOT GO AS LOW AS IFR AT THIS TIME CONSIDERING LEVEL OF CONFIDENCE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...FS AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
329 PM CDT Sun May 3 2015 .SHORT TERM...(This Evening through Monday) Issued at 328 PM CDT SUN MAY 3 2015 Zonal but weak flow aloft continues over the Central Plains between northern and southern branches with a few weak waves moving through. Appears moderate mid-level isentropic lift combined with one of these waves to spark overnight convection, with another wave keeping isolated showers going in eastern Kansas into the early afternoon. High- based nature of this activity keeping much precip from what there is in check however. Water vapor imagery suggesting a stronger wave rotating northeast out of eastern New Mexico with convection firing ahead of it into southeastern Colorado. Cold front was from northwestern Kansas into northeastern Nebraska early this afternoon with a few cumulus along it in central Nebraska. Dewpoints have dropped to around 40F in southwest Kansas with thermal ridge ahead of front pushing temp at CNK to near record levels. Precipitation chances remain the main challenge through Monday afternoon. Recent HRRR and RAP runs continue to attempt to produce convection along the front, but have been too fast to do so. With low levels rather dry to the west, the main player with convection to the west and south could be via the New Mexico wave, or other convective-induced waves from eastern Colorado. Isentropic upglide looks less impressive than this morning but some is again present and could be enough to continue or even produce convection into east central Kansas late this evening and into much of Monday. Other prime scenario for convection seems to be with eventual convection generated in eastern Nebraska sinking south into northeast Kansas on decent 850mb moisture convergence as a moderate low level jet veers with time. This could linger well into Monday morning, and with the earlier possibilities as well, have kept chance PoPs going into the morning Monday, with lesser confidence in precip in the northwest counties nearer the drier low level air. Details in precip activity Monday afternoon will be largely impacted by the earlier activity, but models increase low level moisture further, though NAM likely a bit aggressive again, with CAPE possibly near 2000 J/kg ahead of any outflow or front/effective front. Shear values again look meager to support much severe weather but some potential remains. Have kept highs cooler than today with more cloud/precip/moisture anticipated. .LONG TERM...(Monday Night through Sunday) Issued at 328 PM CDT SUN MAY 3 2015 Models continue to show an active pattern for Monday night through Sunday as they dig another closed low into the southwestern U.S. by the end of the work week. This causes mid level flow to remain from the southwest while gulf moisture continues advecting north. So there looks to be plenty of moisture available with occasional forcing mechanisms passing overhead such that there is a chance for precip in every period of the forecast. The one period with the lowest chance for precip remain Tuesday. There seems to be agreement among the models that shortwave ridge will propagate over eastern KS with some relatively dryer air moving in. Therefore have a dry forecast for northeast and east central KS. North central KS may be close enough to shortwave energy lifting north through the high plains that have kept a small chance for the western counties for Tuesday. The best chance for showers and thunderstorms appears to be late Tuesday night and Wednesday as a well defined shortwave is progged to lift across northeast KS. There are some minor differences in timing of the vort max lifting out. Nevertheless with little or no inhibition to convection expect showers and thunderstorms to overspread the area and have increased POPs into the 70 to 80 percent range. Wednesday night through Saturday does not look like it will be constant precip, but the pattern makes it difficult to say when chances are better than not. With occasional low amplitude waves within the southwest flow and a moist airmass remaining in place, the forecast has a chance for precip each day. There are even some signs of a weak frontal boundary moving into the forecast on Friday which may help focus moisture and provide some lift. Otherwise think chances could be on the increase for Saturday night and Sunday as the upper low begins to lift out of the southern Rockies. Because the GFS is a little further north and doesn`t have as much shortwave energy rotating through the southern plains, have kept POPs in the chance category for now. There should not be any big swings in temps through the period due to the persistent pattern. If anything there may be a slight cool down for Wednesday expecting cloud cover and precip to limit heating. Otherwise temps should be seasonable with lows around 60 and highs in the mid 70s to near 80 && .AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon) Issued at 1229 PM CDT SUN MAY 3 2015 The main aviation concern for the afternoon will be the strong and gusty southerly winds. These will diminish around sunset. Winds likely strong enough overnight to minimize the possibility of wind shear conditions. With the frontal system just off to the North of the terminals, there is some suggestion that KMHK, KTOP/KFOE terminals could at least see some VCSH or perhaps VCTS, but this would be high based and confidence is to low at this point to carry in the TAFs. This is something to stay tuned to though if planning transit to or from the terminals. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...65 LONG TERM...Wolters AVIATION...Drake
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1237 PM CDT Sun May 3 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 346 AM CDT SUN MAY 3 2015 Isolated thunderstorms developed this morning shortly after 06Z in warm/moist advection within the low level jet. Vad wind profiles as well as water vapor imagery shows a mid level wave around 700 mb moving across central Kansas at 08Z. Latest runs of the HRRR and RAP move the isolated convection east into Missouri by 12Z-13Z. After this early morning round of convection, the rest of the day should be dry with clouds gradually decreasing through the early afternoon hours. Deep mixing today along with warm advection will yield highs in the low to mid 80s. Main thermal axis sets up from New Mexico through north central Kansas into northeast Nebraska today. Winds will increase by mid morning as pressure gradient increases. Surface front moves southeast into western Kansas this afternoon while it moves little across Nebraska. Expect afternoon heating out west will overcome convective inhibition for scattered storms to develop. These will remain to the west of north central Kansas into the early evening hours. Models eject weak waves northeast across western Kansas into southern Nebraska overnight. Expect convection to fire along the front in Nebraska tonight with outflow pushing south into north central and northeast Kansas. Southerly low level jet will help to develop scattered showers and thunderstorms overnight. Shear is marginal 20 to 30 kts overnight with MUCAPE 800-1000 J/kg. Expect some strong storms are possible with a few severe storms not out of the question later this evening across north central Kansas. Hail and winds will be the main hazards. Lows tonight will be mild with readings in the lower 60s. .LONG TERM...(Monday through Saturday) Issued at 346 AM CDT SUN MAY 3 2015 A wet pattern looks to be setting up for this upcoming week with several chances for precipitation all the way into next weekend. By Monday, a mid-level ridge will stretch across the Southern Plains and southeastern U.S. with a surface low centered over southwest Kansas. Models show the associated cold front extending into north central Kansas and southeast Nebraska, however the last few models runs have shown this front becoming fairly stationary over northern Kansas Monday into Monday night, limiting the southeastern extent of precipitation chances across the CWA. As a result, have continued to diminish PoPs across far east central Kansas through that period with likely PoPs along the KS/NE border with the stationary boundary. There continues to be the potential for some strong to severe thunderstorms to develop along this stationary boundary Monday afternoon into Monday evening as storms should be surface-based due to little to no inhibition present. The NAM continues to be the most aggressive with the amount of available moisture, thus increasing the parameters for severe thunderstorms. However, CAPE values could reach upwards of 1000-2000 J/kg with decent low-level lapse rates. However, 0-6km bulk shear continues to look fairly weak with most models showing upwards of only about 30kts. The main concern with any strong to severe storms will likely be some large hail and potentially some locally heavy rain as thunderstorms may train across north central Kansas into the evening and overnight hours with the low-level jet looking to be parallel to the boundary. The mid-level ridge should stretch further northward into the Central Plains Monday night into Tuesday, helping to push the cold front northward into Nebraska and further limiting the precipitation potential across the southeastern portions of the forecast area. At this time, Tuesday looks to show the best potential for being dry across much of the forecast area. However, focus quickly shifts to the southwest where a mid-level trough will be beginning to lift northeastward across the High Plains through Wednesday and into the Northern Plains by Wednesday night. At the surface, a low pressure system will strengthen across the High Plains but looks to become anchored over that region through mid to late week, resulting in persistent southerly surface winds advecting warm, moist air into the region. The combination of this steady stream of moisture and a frontal boundary that will likely remain hung up just west of the forecast area through much of the remainder of the week will help to support continued scattered shower and thunderstorm chances through the end of the week. While there is decent model agreement with the timing and tracking of the mid-level trough and the development of weak embedded waves within the pattern by late week, there is less agreement with the surface features in when the associated cold front will become tilted enough to move into the forecast area during the latter part of the week. Due to the low confidence in this boundary placement, have lowered PoPs some from the consensus blend but still have chance PoPs in for the entire forecast area through Saturday. This fairly stationary surface pattern should result in fairly similar temperatures throughout the week with highs in the 70s/near 80, lows in the upper 50s/low 60s, and dewpoints in the 50s and 60s. && .AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon) Issued at 1229 PM CDT SUN MAY 3 2015 The main aviation concern for the afternoon will be the strong and gusty southerly winds. These will diminish around sunset. Winds likely strong enough overnight to minimize the possibility of wind shear conditions. With the frontal system just off to the North of the terminals, there is some suggestion that KMHK, KTOP/KFOE terminals could at least see some VCSH or perhaps VCTS, but this would be high based and confidence is to low at this point to carry in the TAFs. This is something to stay tuned to though if planning transit to or from the terminals. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...Hennecke AVIATION...Drake
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1211 PM CDT SUN MAY 3 2015 ...UPDATED SYNOPSIS AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1207 PM CDT SUN MAY 3 2015 AT 12Z SUNDAY AN UPPER LEVEL TROUGH/LOW WAS LOCATED JUST OFF THE SOUTHERN CALIFORNIA COAST WITH WEAK UPPER LEVEL RIDGING OCCURRING OVER THE SOUTHERN AND CENTRAL PLAINS. FURTHER NORTH AN UPPER LEVEL TROUGH WAS CROSS THE NORTHERN PLAINS. AT 12Z SUNDAY A 700MB TROUGH WAS LOCATED OVER WESTERN KANSAS WITH A THERMAL RIDGE AXIS EXTENDING FROM SOUTHEAST COLORADO INTO THE PANHANDLE OF TEXAS. A SURFACE COLD FRONT STRETCHED FROM EASTERN WYOMING, ACROSS NEBRASKA, TO SOUTHWEST MINNESOTA. JUST SOUTH OF THIS COLD FRONT A A SURFACE TROUGH EXTENDED FROM NORTH CENTRAL NEBRASKA INTO THE TEXAS PANHANDLE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 320 AM CDT SUN MAY 3 2015 THE MAIN CONCERN FOR THE SHORT TERM IS CONVECTIVE CHANCES, COVERAGE, AND STRENGTH FOR LATE THIS AFTERNOON INTO THE EVENING. ON THE SYNOPTIC SCALE, A RATHER WEAK WEST-TO-EAST FLOW WAS FOUND IN THE MID AND UPPER TROPOSPHERE, WITH 500MB FLOW AVERAGING ABOUT 15 TO 20 KNOTS ACROSS THE CENTRAL ROCKIES AND PLAINS WITH 250MB FLOW NOT MUCH STRONGER AT 25 TO 30 KNOTS. THIS IS MORE LIKE A LATE JUNE/EARLY JULY FLOW REGIME. AS A RESULT, THE CONVECTION THAT IS EXPECTED TO DEVELOP LATE THIS AFTERNOON WILL BEHAVE MORE LIKE LATE JUNE/JULY STORMS: SLOW MOVING, AND MARGINAL-AT-BEST SEVERE WEATHER PROSPECTS. THUNDERSTORMS WILL DEVELOP IN THE DEEPLY MIXED AIRMASS THAT WILL DEVELOP ALONG AND WEST OF THE LEE TROUGH AXIS/NEBULOUS DRYLINE. THE CONVERGENCE WILL NOT BE ALL THAT STRONG, BUT THE LOWER TO MID TROPOSPHERIC LAPSE RATES OF EARLY MAY WILL BE STEEP ENOUGH SUCH THAT EVEN WEAK CONVERGENCE WILL AID IN THUNDERSTORM DEVELOPMENT ALONG THE WEAK DRYLINE/LEE TROUGH. WHEN COMPARED AGAINST THE GFS, ECMWF, AND WRF-ARW, THE NAM12/NMMB SURFACE DEWPOINTS APPEAR TO BE TOO AMBITIOUS WITH MID 50S DEWPOINTS AS FAR WEST AS HIGHWAY 283 BY LATE AFTERNOON, RESULTING IN LARGE AREA OF 2000+ J/KG SBCAPE. THERE WILL LIKELY BE A BIT MORE MIXING THAN WHAT THE NAM12 SHOWS WITH TEMPERATURES WARMING WELL INTO THE MID TO UPPER 80S AND THE LACK OF ANY EASTERLY COMPONENT WIND. THAT SAID, THE EARLY RUNS OF THE RAP13 AND HRRR APPEAR TO BE WHACKED OUT WITH SURFACE FLOW TOO VEERED OUT/WESTERLY COMPONENT WITH DEWPOINTS TANKING INTO THE UPPER 30S TO AROUND 40F FOR ALL OF SOUTHWEST KANSAS. BELIEVE THAT SOMETHING IN THE MIDDLE IS MORE REALISTIC IN TERMS OF WHAT WILL REALLY PAN OUT WITH THE SURFACE SETUP LATE THIS AFTERNOON. NEVERTHELESS, 1000 TO 1500 J/KG SBCAPE SHOULD BE REALIZED AHEAD OF THE DEVELOPING CONVECTION THIS AFTERNOON. THE GREATEST THREAT FROM ANY OF THE STORMS WILL BE SOME LOCALIZED DOWNBURST WIND GUSTS IN EXCESS OF 50 KNOTS/58 MPH GIVEN THE ANTICIPATED HIGH TEMPERATURE- DEWPOINT SPREADS APPROACHING 40F LATE THIS AFTERNOON. THE HAIL RISK LOOKS QUITE LOW GIVEN THE POOR CAPE-SHEAR COMBINATION AND LACK OF ANY UPPER TROPOSPHERIC FLOW TO SUPPORT MID-UPPER STORM-RELATIVE SHEAR. THE STRONGEST STORM WILL STILL BE CAPABLE OF QUARTER TO PERHAPS HALF-DOLLAR SIZE HAIL, THOUGH. THE FORECAST POPS OF 40 TO 50 PERCENT WILL COVER AREAS ALONG AND BETWEEN THE HIGHWAY 83 AND 283 CORRIDOR, INCLUDING SCOTT CITY, GARDEN, LIBERAL, NESS CITY, WAKEENEY, AND HAYS. ANTICIPATED SLOW STORM MOTIONS WILL RESULT IN LOCALIZED HEAVY RAINFALL, ESPECIALLY DURING THE EVENING WHEN UPSCALE GROWTH OCCURS BETWEEN 00-03Z. LOSS OF DIURNAL HEATING WILL LIKELY RESULT IN THE DEMISE OF CONVECTION BY 06Z MUCH LIKE WE HAVE SEEN OVER THE PAST COUPLE NIGHTS OUT ALONG THE KS-CO BORDER. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 AN UPPER LEVEL LOW IS EXPECTED TO MOVE INTO THE DESERT SOUTHWEST SUNDAY INTO MONDAY THEN WEAKEN INTO AN OPEN WAVE AND CURLS NORTHEASTWARD INTO THE CENTRAL ROCKIES BY TUESDAY INTO TUESDAY NIGHT. THIS FEATURE THEN MOVES INTO THE CENTRAL PLAINS WEDNESDAY THEN INTO THE NORTHERN PLAINS THURSDAY. MOISTURE ABOVE WESTERN KANSAS WILL INCREASE AS THIS FEATURE APPROACHES LEADING TO INCREASING CLOUDS MONDAY WITH MOSTLY CLOUDY SKIES EXPECTED MONDAY NIGHT THROUGH TUESDAY NIGHT. A FRONTAL BOUNDARY AT THE SURFACE IS ANTICIPATED TO SPRAWL OUT ACROSS WEST CENTRAL KANSAS MONDAY THEN SHIFT NORTHWARD MONDAY NIGHT INTO TUESDAY AS A WARM FRONT. WINDS AHEAD OF THIS BOUNDARY WILL GENERALLY BE FROM A SOUTHERLY DIRECTION WITH WINDS BEHIND THIS BOUNDARY FROM MORE OF A NORTHERLY DIRECTION. A DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS THE EASTERN UNITED STATES WITH TRAJECTORIES ON THE WEST SIDE BRINGING UP COPIOUS AMOUNTS OF MOISTURE FROM THE GULF INTO THE CENTRAL PLAINS. AS FOR PRECIPITATION CHANCES, THUNDERSTORMS MAY BE POSSIBLE ACROSS CENTRAL KANSAS MONDAY MORNING BUT SHOULD QUICKLY MOVE OUT OF THE CWA BY LATE MORNING. ADDITIONAL THUNDERSTORMS ARE PROGGED TO DEVELOP ACROSS WESTERN KANSAS IN THE AFTERNOON AND SPREAD ACROSS THE REMAINDER OF THE AREA MONDAY NIGHT. A FEW STORMS COULD BECOME STRONG TO SEVERE ACROSS CENTRAL KANSAS DEPENDING ON HOW MUCH HEATING OCCURS DURING THE DAY. RAIN CHANCES BECOME LIKELY TUESDAY AS MOISTURE CONTINUES TO BE PULLED UP FROM THE GULF AND PWAT`S SURPASS AN INCH. MEANWHILE, AN UPPER LEVEL LOW ENTERS THE WESTERN UNITED STATES TUESDAY THEN SLIDES SOUTHWARD INTO THE DESERT SOUTHWEST BY THURSDAY. THIS LOW THEN CURLS NORTHEAST INTO THE CENTRAL ROCKIES FRIDAY THEN INTO THE NORTHERN ROCKIES WEEKEND. WEAK SHORTWAVES ARE EXPECTED TO MOVE AROUND THE PERIPHERY OF THIS SYSTEM AND TOWARDS THE CENTRAL PLAINS FOR THE REMAINDER OF THE WEEK. THIS WILL ALLOW PRECIPITATION CHANCES TO CONTINUE ACROSS THE AREA WITH THE BEST CHANCE OF BENEFICIAL RAINFALL ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. AS FOR TEMPERATURES, HIGHS MONDAY LOOK TO RANGE FROM THE LOWER 70S ACROSS WEST CENTRAL KANSAS WHERE THE FRONTAL BOUNDARY WILL BE LOCATED TO LOWER 80S ACROSS SOUTH CENTRAL KANSAS. HIGHS TUESDAY ARE ANTICIPATED TO BE AROUND 70 DEGREES. LOWS MONDAY NIGHT AND TUESDAY NIGHT ARE PROGGED TO RANGE FROM AROUND 50 DEGREES ACROSS FAR WESTERN KANSAS TO AROUND 60 DEGREES ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. HIGHS FOR THE REMAINDER OF THE WEEK INTO THE WEEKEND ARE EXPECTED TO BE IN THE UPPER 70S TO LOWER 80S WITH LOWS RANGING FROM AROUND 50 DEGREES ACROSS FAR WESTERN KANSAS TO AROUND 60 DEGREES ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1207 PM CDT SUN MAY 3 2015 A SURFACE BOUNDARY WILL REMAIN NEARLY STATIONARY TODAY ACROSS WESTERN KANSAS TODAY. GIVE THE LOCATION OF THIS SURFACE BOUNDARY THE WINDS TODAY WILL AVERAGE LESS THAN 10 KNOTS. AFTER SUNSET THE PREVAILING WINDS WILL BECOME SOUTHEAST AT 10 TO 15 KNOTS. SCATTERED THUNDERSTORMS ARE ALSO EXPECTED TO DEVELOP ALONG AND EAST OF THIS SURFACE BOUNDARY LATE TODAY AND THEN CONTINUE THROUGH EARLY TONIGHT. BUFR SOUNDINGS KEEP CLOUD BASES WITH THESE STORMS AT OR ABOVE 5000FT AGL SO VFR CONDITIONS ARE EXPECTED WITH THESE STORMS. SOME OF THESE STORMS EARLY THIS EVENING WILL BE CAPABLE OF PRODUCING QUARTER SIZE HAIL AND WIND GUSTS OF 50 TO 60 MPH. AT THIS TIME THE THUNDERSTORMS WILL BE MORE LIKELY AT GCK BETWEEN 23Z SUNDAY AND 02Z MONDAY. AT DDC AND HAY FROM 02Z TO 06Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 88 58 80 57 / 30 30 50 70 GCK 88 55 78 55 / 40 40 60 90 EHA 88 54 75 53 / 30 20 60 80 LBL 90 57 79 56 / 40 50 60 90 HYS 88 58 78 57 / 40 50 60 60 P28 86 60 81 59 / 10 20 20 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURGERT SHORT TERM...UMSCHEID LONG TERM...HOVORKA_42 AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
638 AM CDT Sun May 3 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 346 AM CDT SUN MAY 3 2015 Isolated thunderstorms developed this morning shortly after 06Z in warm/moist advection within the low level jet. Vad wind profiles as well as water vapor imagery shows a mid level wave around 700 mb moving across central Kansas at 08Z. Latest runs of the HRRR and RAP move the isolated convection east into Missouri by 12Z-13Z. After this early morning round of convection, the rest of the day should be dry with clouds gradually decreasing through the early afternoon hours. Deep mixing today along with warm advection will yield highs in the low to mid 80s. Main thermal axis sets up from New Mexico through north central Kansas into northeast Nebraska today. Winds will increase by mid morning as pressure gradient increases. Surface front moves southeast into western Kansas this afternoon while it moves little across Nebraska. Expect afternoon heating out west will overcome convective inhibition for scattered storms to develop. These will remain to the west of north central Kansas into the early evening hours. Models eject weak waves northeast across western Kansas into southern Nebraska overnight. Expect convection to fire along the front in Nebraska tonight with outflow pushing south into north central and northeast Kansas. Southerly low level jet will help to develop scattered showers and thunderstorms overnight. Shear is marginal 20 to 30 kts overnight with MUCAPE 800-1000 J/kg. Expect some strong storms are possible with a few severe storms not out of the question later this evening across north central Kansas. Hail and winds will be the main hazards. Lows tonight will be mild with readings in the lower 60s. .LONG TERM...(Monday through Saturday) Issued at 346 AM CDT SUN MAY 3 2015 A wet pattern looks to be setting up for this upcoming week with several chances for precipitation all the way into next weekend. By Monday, a mid-level ridge will stretch across the Southern Plains and southeastern U.S. with a surface low centered over southwest Kansas. Models show the associated cold front extending into north central Kansas and southeast Nebraska, however the last few models runs have shown this front becoming fairly stationary over northern Kansas Monday into Monday night, limiting the southeastern extent of precipitation chances across the CWA. As a result, have continued to diminish PoPs across far east central Kansas through that period with likely PoPs along the KS/NE border with the stationary boundary. There continues to be the potential for some strong to severe thunderstorms to develop along this stationary boundary Monday afternoon into Monday evening as storms should be surface-based due to little to no inhibition present. The NAM continues to be the most aggressive with the amount of available moisture, thus increasing the parameters for severe thunderstorms. However, CAPE values could reach upwards of 1000-2000 J/kg with decent low-level lapse rates. However, 0-6km bulk shear continues to look fairly weak with most models showing upwards of only about 30kts. The main concern with any strong to severe storms will likely be some large hail and potentially some locally heavy rain as thunderstorms may train across north central Kansas into the evening and overnight hours with the low-level jet looking to be parallel to the boundary. The mid-level ridge should stretch further northward into the Central Plains Monday night into Tuesday, helping to push the cold front northward into Nebraska and further limiting the precipitation potential across the southeastern portions of the forecast area. At this time, Tuesday looks to show the best potential for being dry across much of the forecast area. However, focus quickly shifts to the southwest where a mid-level trough will be beginning to lift northeastward across the High Plains through Wednesday and into the Northern Plains by Wednesday night. At the surface, a low pressure system will strengthen across the High Plains but looks to become anchored over that region through mid to late week, resulting in persistent southerly surface winds advecting warm, moist air into the region. The combination of this steady stream of moisture and a frontal boundary that will likely remain hung up just west of the forecast area through much of the remainder of the week will help to support continued scattered shower and thunderstorm chances through the end of the week. While there is decent model agreement with the timing and tracking of the mid-level trough and the development of weak embedded waves within the pattern by late week, there is less agreement with the surface features in when the associated cold front will become tilted enough to move into the forecast area during the latter part of the week. Due to the low confidence in this boundary placement, have lowered PoPs some from the consensus blend but still have chance PoPs in for the entire forecast area through Saturday. This fairly stationary surface pattern should result in fairly similar temperatures throughout the week with highs in the 70s/near 80, lows in the upper 50s/low 60s, and dewpoints in the 50s and 60s. && .AVIATION...(For the 12Z TAFs through 12Z Monday Morning) Issued at 638 AM CDT SUN MAY 3 2015 Isolated shra and tsra are possible at TOP and FOE terminals through 14Z. VFR conditions are expected through the period outside of convective activity. South to southwest winds will increase to near 15 kts with gusts to 24kts from 14Z-00Z, then decrease to around 10 kts. TSRA may be possible at the terminals after 06Z. Confidence to low for timing at the terminals attm to go with more than VCTS. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...Hennecke AVIATION...53
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
618 AM CDT SUN MAY 3 2015 ...UPDATED AVIATION SECTION... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 320 AM CDT SUN MAY 3 2015 THE MAIN CONCERN FOR THE SHORT TERM IS CONVECTIVE CHANCES, COVERAGE, AND STRENGTH FOR LATE THIS AFTERNOON INTO THE EVENING. ON THE SYNOPTIC SCALE, A RATHER WEAK WEST-TO-EAST FLOW WAS FOUND IN THE MID AND UPPER TROPOSPHERE, WITH 500MB FLOW AVERAGING ABOUT 15 TO 20 KNOTS ACROSS THE CENTRAL ROCKIES AND PLAINS WITH 250MB FLOW NOT MUCH STRONGER AT 25 TO 30 KNOTS. THIS IS MORE LIKE A LATE JUNE/EARLY JULY FLOW REGIME. AS A RESULT, THE CONVECTION THAT IS EXPECTED TO DEVELOP LATE THIS AFTERNOON WILL BEHAVE MORE LIKE LATE JUNE/JULY STORMS: SLOW MOVING, AND MARGINAL-AT-BEST SEVERE WEATHER PROSPECTS. THUNDERSTORMS WILL DEVELOP IN THE DEEPLY MIXED AIRMASS THAT WILL DEVELOP ALONG AND WEST OF THE LEE TROUGH AXIS/NEBULOUS DRYLINE. THE CONVERGENCE WILL NOT BE ALL THAT STRONG, BUT THE LOWER TO MID TROPOSPHERIC LAPSE RATES OF EARLY MAY WILL BE STEEP ENOUGH SUCH THAT EVEN WEAK CONVERGENCE WILL AID IN THUNDERSTORM DEVELOPMENT ALONG THE WEAK DRYLINE/LEE TROUGH. WHEN COMPARED AGAINST THE GFS, ECMWF, AND WRF-ARW, THE NAM12/NMMB SURFACE DEWPOINTS APPEAR TO BE TOO AMBITIOUS WITH MID 50S DEWPOINTS AS FAR WEST AS HIGHWAY 283 BY LATE AFTERNOON, RESULTING IN LARGE AREA OF 2000+ J/KG SBCAPE. THERE WILL LIKELY BE A BIT MORE MIXING THAN WHAT THE NAM12 SHOWS WITH TEMPERATURES WARMING WELL INTO THE MID TO UPPER 80S AND THE LACK OF ANY EASTERLY COMPONENT WIND. THAT SAID, THE EARLY RUNS OF THE RAP13 AND HRRR APPEAR TO BE WHACKED OUT WITH SURFACE FLOW TOO VEERED OUT/WESTERLY COMPONENT WITH DEWPOINTS TANKING INTO THE UPPER 30S TO AROUND 40F FOR ALL OF SOUTHWEST KANSAS. BELIEVE THAT SOMETHING IN THE MIDDLE IS MORE REALISTIC IN TERMS OF WHAT WILL REALLY PAN OUT WITH THE SURFACE SETUP LATE THIS AFTERNOON. NEVERTHELESS, 1000 TO 1500 J/KG SBCAPE SHOULD BE REALIZED AHEAD OF THE DEVELOPING CONVECTION THIS AFTERNOON. THE GREATEST THREAT FROM ANY OF THE STORMS WILL BE SOME LOCALIZED DOWNBURST WIND GUSTS IN EXCESS OF 50 KNOTS/58 MPH GIVEN THE ANTICIPATED HIGH TEMPERATURE- DEWPOINT SPREADS APPROACHING 40F LATE THIS AFTERNOON. THE HAIL RISK LOOKS QUITE LOW GIVEN THE POOR CAPE-SHEAR COMBINATION AND LACK OF ANY UPPER TROPOSPHERIC FLOW TO SUPPORT MID-UPPER STORM-RELATIVE SHEAR. THE STRONGEST STORM WILL STILL BE CAPABLE OF QUARTER TO PERHAPS HALF-DOLLAR SIZE HAIL, THOUGH. THE FORECAST POPS OF 40 TO 50 PERCENT WILL COVER AREAS ALONG AND BETWEEN THE HIGHWAY 83 AND 283 CORRIDOR, INCLUDING SCOTT CITY, GARDEN, LIBERAL, NESS CITY, WAKEENEY, AND HAYS. ANTICIPATED SLOW STORM MOTIONS WILL RESULT IN LOCALIZED HEAVY RAINFALL, ESPECIALLY DURING THE EVENING WHEN UPSCALE GROWTH OCCURS BETWEEN 00-03Z. LOSS OF DIURNAL HEATING WILL LIKELY RESULT IN THE DEMISE OF CONVECTION BY 06Z MUCH LIKE WE HAVE SEEN OVER THE PAST COUPLE NIGHTS OUT ALONG THE KS-CO BORDER. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 AN UPPER LEVEL LOW IS EXPECTED TO MOVE INTO THE DESERT SOUTHWEST SUNDAY INTO MONDAY THEN WEAKEN INTO AN OPEN WAVE AND CURLS NORTHEASTWARD INTO THE CENTRAL ROCKIES BY TUESDAY INTO TUESDAY NIGHT. THIS FEATURE THEN MOVES INTO THE CENTRAL PLAINS WEDNESDAY THEN INTO THE NORTHERN PLAINS THURSDAY. MOISTURE ABOVE WESTERN KANSAS WILL INCREASE AS THIS FEATURE APPROACHES LEADING TO INCREASING CLOUDS MONDAY WITH MOSTLY CLOUDY SKIES EXPECTED MONDAY NIGHT THROUGH TUESDAY NIGHT. A FRONTAL BOUNDARY AT THE SURFACE IS ANTICIPATED TO SPRAWL OUT ACROSS WEST CENTRAL KANSAS MONDAY THEN SHIFT NORTHWARD MONDAY NIGHT INTO TUESDAY AS A WARM FRONT. WINDS AHEAD OF THIS BOUNDARY WILL GENERALLY BE FROM A SOUTHERLY DIRECTION WITH WINDS BEHIND THIS BOUNDARY FROM MORE OF A NORTHERLY DIRECTION. A DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS THE EASTERN UNITED STATES WITH TRAJECTORIES ON THE WEST SIDE BRINGING UP COPIOUS AMOUNTS OF MOISTURE FROM THE GULF INTO THE CENTRAL PLAINS. AS FOR PRECIPITATION CHANCES, THUNDERSTORMS MAY BE POSSIBLE ACROSS CENTRAL KANSAS MONDAY MORNING BUT SHOULD QUICKLY MOVE OUT OF THE CWA BY LATE MORNING. ADDITIONAL THUNDERSTORMS ARE PROGGED TO DEVELOP ACROSS WESTERN KANSAS IN THE AFTERNOON AND SPREAD ACROSS THE REMAINDER OF THE AREA MONDAY NIGHT. A FEW STORMS COULD BECOME STRONG TO SEVERE ACROSS CENTRAL KANSAS DEPENDING ON HOW MUCH HEATING OCCURS DURING THE DAY. RAIN CHANCES BECOME LIKELY TUESDAY AS MOISTURE CONTINUES TO BE PULLED UP FROM THE GULF AND PWAT`S SURPASS AN INCH. MEANWHILE, AN UPPER LEVEL LOW ENTERS THE WESTERN UNITED STATES TUESDAY THEN SLIDES SOUTHWARD INTO THE DESERT SOUTHWEST BY THURSDAY. THIS LOW THEN CURLS NORTHEAST INTO THE CENTRAL ROCKIES FRIDAY THEN INTO THE NORTHERN ROCKIES WEEKEND. WEAK SHORTWAVES ARE EXPECTED TO MOVE AROUND THE PERIPHERY OF THIS SYSTEM AND TOWARDS THE CENTRAL PLAINS FOR THE REMAINDER OF THE WEEK. THIS WILL ALLOW PRECIPITATION CHANCES TO CONTINUE ACROSS THE AREA WITH THE BEST CHANCE OF BENEFICIAL RAINFALL ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. AS FOR TEMPERATURES, HIGHS MONDAY LOOK TO RANGE FROM THE LOWER 70S ACROSS WEST CENTRAL KANSAS WHERE THE FRONTAL BOUNDARY WILL BE LOCATED TO LOWER 80S ACROSS SOUTH CENTRAL KANSAS. HIGHS TUESDAY ARE ANTICIPATED TO BE AROUND 70 DEGREES. LOWS MONDAY NIGHT AND TUESDAY NIGHT ARE PROGGED TO RANGE FROM AROUND 50 DEGREES ACROSS FAR WESTERN KANSAS TO AROUND 60 DEGREES ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. HIGHS FOR THE REMAINDER OF THE WEEK INTO THE WEEKEND ARE EXPECTED TO BE IN THE UPPER 70S TO LOWER 80S WITH LOWS RANGING FROM AROUND 50 DEGREES ACROSS FAR WESTERN KANSAS TO AROUND 60 DEGREES ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 612 AM CDT SUN MAY 3 2015 A FRONTAL BOUNDARY WILL BIFURCATE THE AREA TODAY WITH SOUTHERLY WINDS FELT AHEAD OF THE FRONT WITH NORTHWESTERLY WINDS BEHIND THE FRONT. THE DDC TERMINAL LOOKS TO STAY AHEAD OF THE FRONT THROUGHOUT THE DAY WHERE AS THE GCK AND HYS TERMINALS LOOK TO BE VERY CLOSE TO THE FRONT THIS MORNING. THIS IS THE REASON FOR THE VRB CONDITIONS CURRENTLY IN THE TAFS. WINDS LOOK TO BE FROM A SOUTHERLY DIRECTION BY THIS AFTERNOON AS THE AFOREMENTIONED FRONT MOVES NORTH AS A WARM FRONT. VFR CONDITIONS WILL PREVAIL TODAY WITH SCATTERED HIGH CLOUDS THIS MORNING. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS AROUND THE HYS TERMINAL THIS EVENING AND A PROB30 HAS BEEN ADDED TO ACCOUNT FOR THIS. && .PRELIMINARY POINT TEMPS/POPS... DDC 88 58 80 57 / 30 30 50 70 GCK 88 55 78 55 / 40 40 60 90 EHA 88 54 75 53 / 30 20 60 80 LBL 90 57 79 56 / 40 50 60 90 HYS 87 58 78 57 / 40 50 60 60 P28 86 60 81 59 / 10 20 20 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...UMSCHEID LONG TERM...HOVORKA_42 AVIATION...HOVORKA_42
AREA FORECAST DISCUSSION
NWS TOPEKA KS
404 AM CDT Sun May 3 2015 .SHORT TERM...(Today and Tonight) Issued at 346 AM CDT SUN MAY 3 2015 Isolated thunderstorms developed this morning shortly after 06Z in warm/moist advection within the low level jet. Vad wind profiles as well as water vapor imagery shows a mid level wave around 700 mb moving across central Kansas at 08Z. Latest runs of the HRRR and RAP move the isolated convection east into Missouri by 12Z-13Z. After this early morning round of convection, the rest of the day should be dry with clouds gradually decreasing through the early afternoon hours. Deep mixing today along with warm advection will yield highs in the low to mid 80s. Main thermal axis sets up from New Mexico through north central Kansas into northeast Nebraska today. Winds will increase by mid morning as pressure gradient increases. Surface front moves southeast into western Kansas this afternoon while it moves little across Nebraska. Expect afternoon heating out west will overcome convective inhibition for scattered storms to develop. These will remain to the west of north central Kansas into the early evening hours. Models eject weak waves northeast across western Kansas into southern Nebraska overnight. Expect convection to fire along the front in Nebraska tonight with outflow pushing south into north central and northeast Kansas. Southerly low level jet will help to develop scattered showers and thunderstorms overnight. Shear is marginal 20 to 30 kts overnight with MUCAPE 800-1000 J/kg. Expect some strong storms are possible with a few severe storms not out of the question later this evening across north central Kansas. Hail and winds will be the main hazards. Lows tonight will be mild with readings in the lower 60s. .LONG TERM...(Monday through Saturday) Issued at 346 AM CDT SUN MAY 3 2015 A wet pattern looks to be setting up for this upcoming week with several chances for precipitation all the way into next weekend. By Monday, a mid-level ridge will stretch across the Southern Plains and southeastern U.S. with a surface low centered over southwest Kansas. Models show the associated cold front extending into north central Kansas and southeast Nebraska, however the last few models runs have shown this front becoming fairly stationary over northern Kansas Monday into Monday night, limiting the southeastern extent of precipitation chances across the CWA. As a result, have continued to diminish PoPs across far east central Kansas through that period with likely PoPs along the KS/NE border with the stationary boundary. There continues to be the potential for some strong to severe thunderstorms to develop along this stationary boundary Monday afternoon into Monday evening as storms should be surface-based due to little to no inhibition present. The NAM continues to be the most aggressive with the amount of available moisture, thus increasing the parameters for severe thunderstorms. However, CAPE values could reach upwards of 1000-2000 J/kg with decent low-level lapse rates. However, 0-6km bulk shear continues to look fairly weak with most models showing upwards of only about 30kts. The main concern with any strong to severe storms will likely be some large hail and potentially some locally heavy rain as thunderstorms may train across north central Kansas into the evening and overnight hours with the low-level jet looking to be parallel to the boundary. The mid-level ridge should stretch further northward into the Central Plains Monday night into Tuesday, helping to push the cold front northward into Nebraska and further limiting the precipitation potential across the southeastern portions of the forecast area. At this time, Tuesday looks to show the best potential for being dry across much of the forecast area. However, focus quickly shifts to the southwest where a mid-level trough will be beginning to lift northeastward across the High Plains through Wednesday and into the Northern Plains by Wednesday night. At the surface, a low pressure system will strengthen across the High Plains but looks to become anchored over that region through mid to late week, resulting in persistent southerly surface winds advecting warm, moist air into the region. The combination of this steady stream of moisture and a frontal boundary that will likely remain hung up just west of the forecast area through much of the remainder of the week will help to support continued scattered shower and thunderstorm chances through the end of the week. While there is decent model agreement with the timing and tracking of the mid-level trough and the development of weak embedded waves within the pattern by late week, there is less agreement with the surface features in when the associated cold front will become tilted enough to move into the forecast area during the latter part of the week. Due to the low confidence in this boundary placement, have lowered PoPs some from the consensus blend but still have chance PoPs in for the entire forecast area through Saturday. This fairly stationary surface pattern should result in fairly similar temperatures throughout the week with highs in the 70s/near 80, lows in the upper 50s/low 60s, and dewpoints in the 50s and 60s. && .AVIATION...(For the 06Z TAFs through 06Z Sunday Night) Issued at 1126 PM CDT SAT MAY 2 2015 VFR conditions expected through most of the taf period. There is a slight chance for showers and storms towards the end of the period, but confidence is low on timing at this point. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...Hennecke AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
321 AM CDT SUN MAY 3 2015 ...UPDATED SHORT TERM AND LONG TERM SECTIONS... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 320 AM CDT SUN MAY 3 2015 THE MAIN CONCERN FOR THE SHORT TERM IS CONVECTIVE CHANCES, COVERAGE, AND STRENGTH FOR LATE THIS AFTERNOON INTO THE EVENING. ON THE SYNOPTIC SCALE, A RATHER WEAK WEST-TO-EAST FLOW WAS FOUND IN THE MID AND UPPER TROPOSPHERE, WITH 500MB FLOW AVERAGING ABOUT 15 TO 20 KNOTS ACROSS THE CENTRAL ROCKIES AND PLAINS WITH 250MB FLOW NOT MUCH STRONGER AT 25 TO 30 KNOTS. THIS IS MORE LIKE A LATE JUNE/EARLY JULY FLOW REGIME. AS A RESULT, THE CONVECTION THAT IS EXPECTED TO DEVELOP LATE THIS AFTERNOON WILL BEHAVE MORE LIKE LATE JUNE/JULY STORMS: SLOW MOVING, AND MARGINAL-AT-BEST SEVERE WEATHER PROSPECTS. THUNDERSTORMS WILL DEVELOP IN THE DEEPLY MIXED AIRMASS THAT WILL DEVELOP ALONG AND WEST OF THE LEE TROUGH AXIS/NEBULOUS DRYLINE. THE CONVERGENCE WILL NOT BE ALL THAT STRONG, BUT THE LOWER TO MID TROPOSPHERIC LAPSE RATES OF EARLY MAY WILL BE STEEP ENOUGH SUCH THAT EVEN WEAK CONVERGENCE WILL AID IN THUNDERSTORM DEVELOPMENT ALONG THE WEAK DRYLINE/LEE TROUGH. WHEN COMPARED AGAINST THE GFS, ECMWF, AND WRF-ARW, THE NAM12/NMMB SURFACE DEWPOINTS APPEAR TO BE TOO AMBITIOUS WITH MID 50S DEWPOINTS AS FAR WEST AS HIGHWAY 283 BY LATE AFTERNOON, RESULTING IN LARGE AREA OF 2000+ J/KG SBCAPE. THERE WILL LIKELY BE A BIT MORE MIXING THAN WHAT THE NAM12 SHOWS WITH TEMPERATURES WARMING WELL INTO THE MID TO UPPER 80S AND THE LACK OF ANY EASTERLY COMPONENT WIND. THAT SAID, THE EARLY RUNS OF THE RAP13 AND HRRR APPEAR TO BE WHACKED OUT WITH SURFACE FLOW TOO VEERED OUT/WESTERLY COMPONENT WITH DEWPOINTS TANKING INTO THE UPPER 30S TO AROUND 40F FOR ALL OF SOUTHWEST KANSAS. BELIEVE THAT SOMETHING IN THE MIDDLE IS MORE REALISTIC IN TERMS OF WHAT WILL REALLY PAN OUT WITH THE SURFACE SETUP LATE THIS AFTERNOON. NEVERTHELESS, 1000 TO 1500 J/KG SBCAPE SHOULD BE REALIZED AHEAD OF THE DEVELOPING CONVECTION THIS AFTERNOON. THE GREATEST THREAT FROM ANY OF THE STORMS WILL BE SOME LOCALIZED DOWNBURST WIND GUSTS IN EXCESS OF 50 KNOTS/58 MPH GIVEN THE ANTICIPATED HIGH TEMPERATURE- DEWPOINT SPREADS APPROACHING 40F LATE THIS AFTERNOON. THE HAIL RISK LOOKS QUITE LOW GIVEN THE POOR CAPE-SHEAR COMBINATION AND LACK OF ANY UPPER TROPOSPHERIC FLOW TO SUPPORT MID-UPPER STORM-RELATIVE SHEAR. THE STRONGEST STORM WILL STILL BE CAPABLE OF QUARTER TO PERHAPS HALF-DOLLAR SIZE HAIL, THOUGH. THE FORECAST POPS OF 40 TO 50 PERCENT WILL COVER AREAS ALONG AND BETWEEN THE HIGHWAY 83 AND 283 CORRIDOR, INCLUDING SCOTT CITY, GARDEN, LIBERAL, NESS CITY, WAKEENEY, AND HAYS. ANTICIPATED SLOW STORM MOTIONS WILL RESULT IN LOCALIZED HEAVY RAINFALL, ESPECIALLY DURING THE EVENING WHEN UPSCALE GROWTH OCCURS BETWEEN 00-03Z. LOSS OF DIURNAL HEATING WILL LIKELY RESULT IN THE DEMISE OF CONVECTION BY 06Z MUCH LIKE WE HAVE SEEN OVER THE PAST COUPLE NIGHTS OUT ALONG THE KS-CO BORDER. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 AN UPPER LEVEL LOW IS EXPECTED TO MOVE INTO THE DESERT SOUTHWEST SUNDAY INTO MONDAY THEN WEAKEN INTO AN OPEN WAVE AND CURLS NORTHEASTWARD INTO THE CENTRAL ROCKIES BY TUESDAY INTO TUESDAY NIGHT. THIS FEATURE THEN MOVES INTO THE CENTRAL PLAINS WEDNESDAY THEN INTO THE NORTHERN PLAINS THURSDAY. MOISTURE ABOVE WESTERN KANSAS WILL INCREASE AS THIS FEATURE APPROACHES LEADING TO INCREASING CLOUDS MONDAY WITH MOSTLY CLOUDY SKIES EXPECTED MONDAY NIGHT THROUGH TUESDAY NIGHT. A FRONTAL BOUNDARY AT THE SURFACE IS ANTICIPATED TO SPRAWL OUT ACROSS WEST CENTRAL KANSAS MONDAY THEN SHIFT NORTHWARD MONDAY NIGHT INTO TUESDAY AS A WARM FRONT. WINDS AHEAD OF THIS BOUNDARY WILL GENERALLY BE FROM A SOUTHERLY DIRECTION WITH WINDS BEHIND THIS BOUNDARY FROM MORE OF A NORTHERLY DIRECTION. A DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS THE EASTERN UNITED STATES WITH TRAJECTORIES ON THE WEST SIDE BRINGING UP COPIOUS AMOUNTS OF MOISTURE FROM THE GULF INTO THE CENTRAL PLAINS. AS FOR PRECIPITATION CHANCES, THUNDERSTORMS MAY BE POSSIBLE ACROSS CENTRAL KANSAS MONDAY MORNING BUT SHOULD QUICKLY MOVE OUT OF THE CWA BY LATE MORNING. ADDITIONAL THUNDERSTORMS ARE PROGGED TO DEVELOP ACROSS WESTERN KANSAS IN THE AFTERNOON AND SPREAD ACROSS THE REMAINDER OF THE AREA MONDAY NIGHT. A FEW STORMS COULD BECOME STRONG TO SEVERE ACROSS CENTRAL KANSAS DEPENDING ON HOW MUCH HEATING OCCURS DURING THE DAY. RAIN CHANCES BECOME LIKELY TUESDAY AS MOISTURE CONTINUES TO BE PULLED UP FROM THE GULF AND PWAT`S SURPASS AN INCH. MEANWHILE, AN UPPER LEVEL LOW ENTERS THE WESTERN UNITED STATES TUESDAY THEN SLIDES SOUTHWARD INTO THE DESERT SOUTHWEST BY THURSDAY. THIS LOW THEN CURLS NORTHEAST INTO THE CENTRAL ROCKIES FRIDAY THEN INTO THE NORTHERN ROCKIES WEEKEND. WEAK SHORTWAVES ARE EXPECTED TO MOVE AROUND THE PERIPHERY OF THIS SYSTEM AND TOWARDS THE CENTRAL PLAINS FOR THE REMAINDER OF THE WEEK. THIS WILL ALLOW PRECIPITATION CHANCES TO CONTINUE ACROSS THE AREA WITH THE BEST CHANCE OF BENEFICIAL RAINFALL ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. AS FOR TEMPERATURES, HIGHS MONDAY LOOK TO RANGE FROM THE LOWER 70S ACROSS WEST CENTRAL KANSAS WHERE THE FRONTAL BOUNDARY WILL BE LOCATED TO LOWER 80S ACROSS SOUTH CENTRAL KANSAS. HIGHS TUESDAY ARE ANTICIPATED TO BE AROUND 70 DEGREES. LOWS MONDAY NIGHT AND TUESDAY NIGHT ARE PROGGED TO RANGE FROM AROUND 50 DEGREES ACROSS FAR WESTERN KANSAS TO AROUND 60 DEGREES ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. HIGHS FOR THE REMAINDER OF THE WEEK INTO THE WEEKEND ARE EXPECTED TO BE IN THE UPPER 70S TO LOWER 80S WITH LOWS RANGING FROM AROUND 50 DEGREES ACROSS FAR WESTERN KANSAS TO AROUND 60 DEGREES ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1203 AM CDT SUN MAY 3 2015 THE PERSISTENT LEE TROUGH WILL REMAIN THROUGH SUNDAY...ALTHOUGH IT WILL PUSH FARTHER EAST, WHICH WILL RESULT IN LESSER WIND ESPECIALLY FOR GCK TERMINAL. IN FACT, GCK SHOULD SEE WIND BELOW 10 KNOTS THROUGH JUST ABOUT THE ENTIRE PERIOD...OUTSIDE OF CONVECTION. SPEAKING OF CONVECTION, THERE IS A PRETTY HIGH LIKELIHOOD OF STORMS LATE TOMORROW AFTERNOON/EVENING ACROSS SOUTHWEST KANSAS, WITH THE GCK TERMINAL MOST LIKELY AFFECTED ANYTIME AFTER 23Z OR SO. && .PRELIMINARY POINT TEMPS/POPS... DDC 88 58 80 57 / 20 30 50 70 GCK 88 55 78 55 / 30 40 60 90 EHA 88 54 75 53 / 30 30 60 80 LBL 90 57 79 56 / 30 30 60 90 HYS 87 58 78 57 / 20 40 60 60 P28 86 60 81 59 / 10 10 20 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...UMSCHEID LONG TERM...HOVORKA_42 AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS GOODLAND KS
220 AM MDT SUN MAY 3 2015 .UPDATE... ISSUED AT 814 PM MDT SAT MAY 2 2015 BASED ON RADAR TRENDS OVER THE LAST COUPLE HOURS AND LATEST MODEL DATA...HAVE LOWERED RAINFALL CHANCES ACROSS MOST OF THE AREA EXCEPT FOR THE YUMA COUNTY AREA AND GREELEY AND WICHITA COUNTIES WHERE RAINFALL IS OR WILL BE MOVING OVER IN THE NEXT FEW HOURS. LATEST DATA INDICATES THE LIFT OVER THE NORTHWEST QUADRANT OF THE IS AT ITS BEST NOW AND WILL DECLINE RATHER QUICKLY OVER THE NEXT COUPLE OF HOURS. FURTHER SOUTH...THE TRACK OF THE 700MB SHORT WAVE TROUGH HAS BEEN PUSHED FURTHER SOUTH FOR TONIGHT...WITH THE MAJORITY OF THE LIFT REMAINING SOUTH OF THE AREA. STILL EXPECTING RAINFALL CHANCES TO END BY OR SHORTLY AFTER MIDNIGHT AS THE LIFT WITH THE SHORT WAVE TROUGH COMES TO AN END AS THE TROUGH FILLS/MOVES OUT OF THE AREA. UPDATE ISSUED AT 552 PM MDT SAT MAY 2 2015 MAIN CHANGE WAS TO INCREASE RAINFALL CHANCES FOR THE EVENING BASED ON LATEST DATA. LATEST RADAR SHOWS LINE OF STORMS AHEAD OF A 700MB SHORT WAVE TROUGH OVER EASTERN COLORADO. 700-500MB FRONTOGENESIS STRENGTHENS RAPIDLY DURING THE EARLY EVENING AND SHIFTS EAST TO THE CENTRAL PART OF THE AREA BY MID EVENING ACCOMPANYING THE 700MB SHORT WAVE TROUGH. MEANWHILE ISENTROPIC LIFT STRENGTHENS THROUGH THE FIRST HALF OF THE EVENING...WITH THE STRONGEST LIFT WEST OF HIGHWAY 25 WHILE CONDENSATION PRESSURE DEFICITS DECLINE. TOWARD MIDNIGHT THE LIFT DECLINES AND CONDENSATION PRESSURE DEFICITS INCREASE AS THE SHORT WAVE TROUGH MOVES ACROSS THE EAST HALF OF THE AREA. WITH THIS IN MIND HAVE THE HIGHEST CHANCES FOR RAINFALL DURING THE FIRST HALF OF THE EVENING MAINLY FOR LOCATIONS SOUTH OF I-70. TOWARD MIDNIGHT...AS ENVIRONMENT BECOMES LESS FAVORABLE FOR RAINFALL...HAVE RAINFALL CHANCES QUICKLY DECLINING OVER THE EAST HALF OF THE AREA. LOOKING AT THE SEVERE WEATHER POTENTIAL...STRONGEST STORMS STILL REMAIN WEST OF THE AREA WHERE THE BEST FORCING IS LOCATED. HAVE HAD SOME ISOLATED STORMS DEVELOP ALONG THE SURFACE TROUGH EXTENDING FROM SOUTHWEST TO NORTHEAST OVER THE CENTRAL PART OF THE AREA. HOWEVER THESE STORMS HAVE BEEN TOO FAR REMOVED FROM THE BETTER UPPER LEVEL FORCING TO LAST VERY LONG AND HAVE BEEN FAIRLY WEAK. AS STORMS MOVE EAST INTO THE AREA...THE LIKELIHOOD FOR SEVERE OUTFLOW WINDS INCREASES OVER THE NEXT HOUR OR SO BEFORE THE INVERSION DEVELOPS. OVERALL SEVERE STORMS ARE MOST LIKELY WEST OF HIGHWAY 25 PRIOR TO 9 PM CT OR 8 PM MT. AFTER THAT THE FORCING...SHEAR...AND INSTABILITY DECLINE. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 157 PM MDT SAT MAY 2 2015 LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY ZONAL FLOW IN PLACE FROM THE GREAT BASIN ACROSS THE CENTRAL ROCKIES INTO THE MISSISSIPPI VALLEY WITH EMBEDDED H5/H7 SHORTWAVE TROUGHS MOVING THROUGH THE MEAN FLOW. AT THE SURFACE LEE TROUGH HAS DEVELOPED ACROSS EASTERN COLORADO WITH A MEAN SURFACE TROUGH FROM THE NE PANHANDLE AND ALONG THE COLORADO BORDER. THUNDERSTORM ACTIVITY HAS ALREADY DEVELOPED ALONG THE CHEYENNE RIDGE AND HIGHER TERRAIN IN COLORADO. THIS AFTERNOON-TONIGHT...RAP ANALYSIS (WHICH IS IN LINE WITH EARLIER NAM) SHOWS 2000 J/KG OF SB CAPE IN PLACE ALONG AND AHEAD OF THE SURFACE TROUGH...CENTERED OVER OUR CWA. CINH APPEARS TO BE WEAKENING...HOWEVER ONLY SOME SHALLOW CU HAVE FORMED SO FAR THIS AFTERNOON. AS MID LEVEL VORTICITY ROTATES FROM THE CENTRAL ROCKIES INTO EASTERN COLORADO I WOULD EXPECT DEVELOPMENT TO SPREAD EAST WHICH IS IN LINE WITH SYNOPTIC SCALE GUIDANCE. HRRR/RAP BOTH INDICATE ISOLATED ACTIVITY DEVELOPING ALONG AND EAST OF THE SURFACE TROUGH OVER OUR CWA WITH ADDITIONAL ACTIVITY SPREADING IN FROM THE WEST. BULK SHEER/HELICITY ARE NOT VERY IMPRESSIVE AT THIS POINT WHERE BETTER INSTABILITY IS IN PLACE (WEST). MOISTURE PROFILES ARE NOT PARTICULARLY IMPRESSIVE...AND THIS COULD LIMIT COVERAGE TO ISOLATE/SCATTERED. BETTER PRECIP SIGNAL AND INSTABILITY ARE SHOW IN IN THE LOWER SHEER ENVIRONMENT...WHERE PULSE TYPE THUNDERSTORMS WOULD BE MORE LIKELY. STEEP MID LEVEL LAPSE RATES AND MODERATE INSTABILITY COULD SUPPORT STRONGER UPDRAFTS/CORES...WITH LARGE HAIL/SEVERE WINDS POSSIBLE. DCAPE VALUES 1000-1500 J/KG AND IN HIGHER TD DEPRESSIONS (MAINLY WEST) DO RAISE A CONCERN FOR INCREASED MICROBURST POTENTIAL WITH SOME OF THESE STORMS. IF ANY OF THIS ACTIVITY WAS TO MOVE INTO THE EASTERN CWA IT COULD BECOME MORE ORGANIZED WITH INCREASING SPEED SHEER (35KT BULK EFFECTIVE SHEER AROUND 00Z). AS THE SUN SETS AND WE LOOSE DAYTIME HEATING ANY LINGERING ACTIVITY SHOULD QUICKLY WEAKEN AS THERE IS ELEVATED CAPE LATE AND ONLY A WEAK LLJ IN PLACE OVERNIGHT. SUNDAY...ANOTHER VERY WARM DAY IS EXPECTED AS SURFACE TROUGH DEEPENS A LITTLE OVER THE CWA AND WAA INCREASES OVER THE CWA. THIS IS IN RESPONSE TO A STRONGER SHORTWAVE TROUGH MOVING INTO THE NORTHERN PLAINS AND A COLD FRONT DROPPING SOUTH INTO NORTHERN NEBRASKA. HIGHS SHOULD BE SIMILAR TO TODAY WITH MOST IN THE 80S...AND A FEW LOCATIONS APPROACHING 90 (MAINLY MCCOOK/HILL CITY). SURFACE TROUGH WILL SHIFT JUST A LITTLE BIT EAST AND LOW LEVEL MOISTURE RETURN COULD BRING HIGHER TD VALUES INTO NORTH CENTRAL KS. NAM MAY BE A LITTLE HIGH...BUT EITHER WAY THIS BETTER BL MOISTURE WILL SUPPORT HIGHER CAPE VALUES IN THE AFTERNOON IN THE 2000-2500 J/KG RANGE. SHEER MAY ALSO BE A LITTLE BIT BETTER WHERE GOOD INSTABILITY IS IN PLACE THAN TODAY...SO THERE MAY BE A BIGGER THREAT FOR MORE ORGANIZE THUNDERSTORM DEVELOPMENT IF ANYTHING IS TO DEVELOP IN THE AFTERNOON. THUNDERSTORM ACTIVITY IS SHOWN TO INITIATE PRIMARILY ALONG SURFACE TROUGH IN THE AFTERNOON. HOWEVER WITH DRIER MOISTURE PROFILES AGAIN IN PLACE COVERAGE COULD BE LIMITED AT LEAST UNTIL LATER WHEN BETTER LARGE SCALE FORCING/DEEPER MOISTURE MOVINGS IN TO THE REGION FROM THE NORTHWEST. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 219 AM MDT SUN MAY 3 2015 THERE WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE TRI STATE AREA ON WEDNESDAY AS AN UPPER LEVEL SHORTWAVE TROUGH MOVES ACROSS THE AREA. THE NEGATIVELY TILTED FEATURE WILL BRING SOME STEEPER LAPSE RATES ALOFT AND AREA CAPE VALUES AROUND 1000 J/KG WEDNESDAY AFTERNOON BASED ON GFS MODEL SOUNDINGS...HOWEVER WEAK SPEED AND DIRECTIONAL SHEAR DOES NOT SUPPORT THE DEVELOPMENT OF STRONGER STORMS. WITH SOUTHERLY ADVECTION THROUGH MOST OF THE PROFILE WEDNESDAY MORNING...DEEP SATURATION IS LIKELY WITH PRECIPITABLE WATER VALUES BETWEEN 0.80 AND 1.00 INCHES. THEREFORE...RAIN SHOWERS AND GENERAL WIDESPREAD THUNDERSTORMS ARE EXPECTED WEDNESDAY AFTERNOON AND EVENING WITH LOCALLY HEAVY RAINFALL POSSIBLE. THE UPPER LEVEL TROUGH CONTINUES TO DEEPEN OVERNIGHT WEDNESDAY AND BECOMES SEPARATED FROM THE UPPER LEVEL FLOW THURSDAY OVER THE WESTERN CONUS. MODELS DIFFER SLIGHTLY ON THE PROGRESSION OF THE PATTERN...BUT THE TIMING IS GENERALLY IN AGREEMENT FOR THE FEATURE TO CONTINUE TO SPIN SLOWLY EASTWARD FOR THURSDAY THROUGH THE BEGINNING OF NEXT WEEKEND...THUS AFFECTING THE TRI STATE AREA. BECAUSE OF THE POSITION OF THE SLOW MOVING UPPER LEVEL SYSTEM...THERE WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS FOR THE ENTIRETY OF THE EXTENDED FORECAST. SURFACE TEMPERATURES THROUGH THE PERIOD WILL REMAIN STEADY DUE TO THE RELATIVELY UNCHANGING UPPER FLOW...WITH HIGHS IN THE MID TO UPPER 70S AND LOWS IN THE UPPER 40S TO LOWER 50S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1055 PM MDT SAT MAY 2 2015 VFR CONDITIONS FORECAST FOR THE 6Z TAFS. STORM ACTIVITY HAS COME TO AN END ACROSS THE TRI-STATE AREA. LIGHT WINDS WILL CONTINUE THROUGH THE REST OF THE NIGHT AND SUNDAY. DURING THE DAY A SURFACE TROUGH WILL MOVE THROUGH THE AREA CAUSING THE WINDS TO TURN CLOCKWISE THROUGH THE DAY...BECOMING NORTHEAST TO EAST BY EARLY EVENING. DURING THE EVENING STORM COVERAGE WILL INCREASE. DID NOT PLACE A MENTION IN THE TAFS AT THIS TIME SINCE THERE IS A POSSIBILITY THE STORMS WILL NOT MOVE NEAR THE SITES UNTIL AFTER 6Z...WHEN CHANCES FOR STORMS WILL INCREASE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...MK AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1055 PM MDT SAT MAY 2 2015 .UPDATE... ISSUED AT 814 PM MDT SAT MAY 2 2015 BASED ON RADAR TRENDS OVER THE LAST COUPLE HOURS AND LATEST MODEL DATA...HAVE LOWERED RAINFALL CHANCES ACROSS MOST OF THE AREA EXCEPT FOR THE YUMA COUNTY AREA AND GREELEY AND WICHITA COUNTIES WHERE RAINFALL IS OR WILL BE MOVING OVER IN THE NEXT FEW HOURS. LATEST DATA INDICATES THE LIFT OVER THE NORTHWEST QUADRANT OF THE IS AT ITS BEST NOW AND WILL DECLINE RATHER QUICKLY OVER THE NEXT COUPLE OF HOURS. FURTHER SOUTH...THE TRACK OF THE 700MB SHORT WAVE TROUGH HAS BEEN PUSHED FURTHER SOUTH FOR TONIGHT...WITH THE MAJORITY OF THE LIFT REMAINING SOUTH OF THE AREA. STILL EXPECTING RAINFALL CHANCES TO END BY OR SHORTLY AFTER MIDNIGHT AS THE LIFT WITH THE SHORT WAVE TROUGH COMES TO AN END AS THE TROUGH FILLS/MOVES OUT OF THE AREA. UPDATE ISSUED AT 552 PM MDT SAT MAY 2 2015 MAIN CHANGE WAS TO INCREASE RAINFALL CHANCES FOR THE EVENING BASED ON LATEST DATA. LATEST RADAR SHOWS LINE OF STORMS AHEAD OF A 700MB SHORT WAVE TROUGH OVER EASTERN COLORADO. 700-500MB FRONTOGENESIS STRENGTHENS RAPIDLY DURING THE EARLY EVENING AND SHIFTS EAST TO THE CENTRAL PART OF THE AREA BY MID EVENING ACCOMPANYING THE 700MB SHORT WAVE TROUGH. MEANWHILE ISENTROPIC LIFT STRENGTHENS THROUGH THE FIRST HALF OF THE EVENING...WITH THE STRONGEST LIFT WEST OF HIGHWAY 25 WHILE CONDENSATION PRESSURE DEFICITS DECLINE. TOWARD MIDNIGHT THE LIFT DECLINES AND CONDENSATION PRESSURE DEFICITS INCREASE AS THE SHORT WAVE TROUGH MOVES ACROSS THE EAST HALF OF THE AREA. WITH THIS IN MIND HAVE THE HIGHEST CHANCES FOR RAINFALL DURING THE FIRST HALF OF THE EVENING MAINLY FOR LOCATIONS SOUTH OF I-70. TOWARD MIDNIGHT...AS ENVIRONMENT BECOMES LESS FAVORABLE FOR RAINFALL...HAVE RAINFALL CHANCES QUICKLY DECLINING OVER THE EAST HALF OF THE AREA. LOOKING AT THE SEVERE WEATHER POTENTIAL...STRONGEST STORMS STILL REMAIN WEST OF THE AREA WHERE THE BEST FORCING IS LOCATED. HAVE HAD SOME ISOLATED STORMS DEVELOP ALONG THE SURFACE TROUGH EXTENDING FROM SOUTHWEST TO NORTHEAST OVER THE CENTRAL PART OF THE AREA. HOWEVER THESE STORMS HAVE BEEN TOO FAR REMOVED FROM THE BETTER UPPER LEVEL FORCING TO LAST VERY LONG AND HAVE BEEN FAIRLY WEAK. AS STORMS MOVE EAST INTO THE AREA...THE LIKELIHOOD FOR SEVERE OUTFLOW WINDS INCREASES OVER THE NEXT HOUR OR SO BEFORE THE INVERSION DEVELOPS. OVERALL SEVERE STORMS ARE MOST LIKELY WEST OF HIGHWAY 25 PRIOR TO 9 PM CT OR 8 PM MT. AFTER THAT THE FORCING...SHEAR...AND INSTABILITY DECLINE. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 157 PM MDT SAT MAY 2 2015 LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY ZONAL FLOW IN PLACE FROM THE GREAT BASIN ACROSS THE CENTRAL ROCKIES INTO THE MISSISSIPPI VALLEY WITH EMBEDDED H5/H7 SHORTWAVE TROUGHS MOVING THROUGH THE MEAN FLOW. AT THE SURFACE LEE TROUGH HAS DEVELOPED ACROSS EASTERN COLORADO WITH A MEAN SURFACE TROUGH FROM THE NE PANHANDLE AND ALONG THE COLORADO BORDER. THUNDERSTORM ACTIVITY HAS ALREADY DEVELOPED ALONG THE CHEYENNE RIDGE AND HIGHER TERRAIN IN COLORADO. THIS AFTERNOON-TONIGHT...RAP ANALYSIS (WHICH IS IN LINE WITH EARLIER NAM) SHOWS 2000 J/KG OF SB CAPE IN PLACE ALONG AND AHEAD OF THE SURFACE TROUGH...CENTERED OVER OUR CWA. CINH APPEARS TO BE WEAKENING...HOWEVER ONLY SOME SHALLOW CU HAVE FORMED SO FAR THIS AFTERNOON. AS MID LEVEL VORTICITY ROTATES FROM THE CENTRAL ROCKIES INTO EASTERN COLORADO I WOULD EXPECT DEVELOPMENT TO SPREAD EAST WHICH IS IN LINE WITH SYNOPTIC SCALE GUIDANCE. HRRR/RAP BOTH INDICATE ISOLATED ACTIVITY DEVELOPING ALONG AND EAST OF THE SURFACE TROUGH OVER OUR CWA WITH ADDITIONAL ACTIVITY SPREADING IN FROM THE WEST. BULK SHEER/HELICITY ARE NOT VERY IMPRESSIVE AT THIS POINT WHERE BETTER INSTABILITY IS IN PLACE (WEST). MOISTURE PROFILES ARE NOT PARTICULARLY IMPRESSIVE...AND THIS COULD LIMIT COVERAGE TO ISOLATE/SCATTERED. BETTER PRECIP SIGNAL AND INSTABILITY ARE SHOW IN IN THE LOWER SHEER ENVIRONMENT...WHERE PULSE TYPE THUNDERSTORMS WOULD BE MORE LIKELY. STEEP MID LEVEL LAPSE RATES AND MODERATE INSTABILITY COULD SUPPORT STRONGER UPDRAFTS/CORES...WITH LARGE HAIL/SEVERE WINDS POSSIBLE. DCAPE VALUES 1000-1500 J/KG AND IN HIGHER TD DEPRESSIONS (MAINLY WEST) DO RAISE A CONCERN FOR INCREASED MICROBURST POTENTIAL WITH SOME OF THESE STORMS. IF ANY OF THIS ACTIVITY WAS TO MOVE INTO THE EASTERN CWA IT COULD BECOME MORE ORGANIZED WITH INCREASING SPEED SHEER (35KT BULK EFFECTIVE SHEER AROUND 00Z). AS THE SUN SETS AND WE LOOSE DAYTIME HEATING ANY LINGERING ACTIVITY SHOULD QUICKLY WEAKEN AS THERE IS ELEVATED CAPE LATE AND ONLY A WEAK LLJ IN PLACE OVERNIGHT. SUNDAY...ANOTHER VERY WARM DAY IS EXPECTED AS SURFACE TROUGH DEEPENS A LITTLE OVER THE CWA AND WAA INCREASES OVER THE CWA. THIS IS IN RESPONSE TO A STRONGER SHORTWAVE TROUGH MOVING INTO THE NORTHERN PLAINS AND A COLD FRONT DROPPING SOUTH INTO NORTHERN NEBRASKA. HIGHS SHOULD BE SIMILAR TO TODAY WITH MOST IN THE 80S...AND A FEW LOCATIONS APPROACHING 90 (MAINLY MCCOOK/HILL CITY). SURFACE TROUGH WILL SHIFT JUST A LITTLE BIT EAST AND LOW LEVEL MOISTURE RETURN COULD BRING HIGHER TD VALUES INTO NORTH CENTRAL KS. NAM MAY BE A LITTLE HIGH...BUT EITHER WAY THIS BETTER BL MOISTURE WILL SUPPORT HIGHER CAPE VALUES IN THE AFTERNOON IN THE 2000-2500 J/KG RANGE. SHEER MAY ALSO BE A LITTLE BIT BETTER WHERE GOOD INSTABILITY IS IN PLACE THAN TODAY...SO THERE MAY BE A BIGGER THREAT FOR MORE ORGANIZE THUNDERSTORM DEVELOPMENT IF ANYTHING IS TO DEVELOP IN THE AFTERNOON. THUNDERSTORM ACTIVITY IS SHOWN TO INITIATE PRIMARILY ALONG SURFACE TROUGH IN THE AFTERNOON. HOWEVER WITH DRIER MOISTURE PROFILES AGAIN IN PLACE COVERAGE COULD BE LIMITED AT LEAST UNTIL LATER WHEN BETTER LARGE SCALE FORCING/DEEPER MOISTURE MOVINGS IN TO THE REGION FROM THE NORTHWEST. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 233 PM MDT SAT MAY 2 2015 UPPER LEVEL FLOW WILL BE SOUTHWEST FROM SUNDAY NIGHT THROUGH TUESDAY AHEAD OF A LOW MOVING EAST FROM THE DESERT SOUTHWEST INTO THE CENTRAL AND SOUTHERN ROCKIES. A SURFACE TROUGH NEAR NORTHWEST KANSAS WILL MOVE EAST MONDAY. HIGH PRESSURE WILL BUILD INTO NORTHWEST KANSAS MONDAY NIGHT AND TUESDAY. AN AREA OF LOW PRESSURE WILL MOVE INTO COLORADO TUESDAY. A SHORTWAVE SHOULD AFFECT THE FA SUNDAY EVENING AND INITIATE STORMS NEAR THE SURFACE TROUGH OVER NORTHEAST COLORADO INTO SOUTHWEST NEBRASKA. PLAN TO USE HIGH CHANCE POPS IN THAT AREA WITH LOWER CHANCE POPS ELSEWHERE ACROSS THE FA. PLAN TO KEEP HIGHER CHANCE POPS ACROSS THE NORTHERN FA AS STORMS DRIFT NORTHEAST INTO THE FA OVERNIGHT. THERE SHOULD BE A LULL MONDAY MORNING BEHIND THE EXITING WAVE. POPS WILL INCREASE TO HIGH CHANCE MONDAY AFTERNOON AND EVENING AS THE NEXT SHORTWAVE COMES THROUGH. MOISTURE AND DYNAMICS LOOK GOOD FOR MONDAY NIGHT SO WILL CONTINUE HIGH CHANCE AND LIKELY POPS. GOOD DYNAMICS AND MOISTURE CONTINUE TO STREAM ACROSS THE FA TUESDAY AS THE MAIN TROUGH MOVES INTO THE AREA. PRECIPITABLE WATER VALUES ACROSS THE FA FOR TUESDAY RANGE FROM 1.0 TO 1.2 INCHES. PLAN TO CONTINUE LIKELY AND DEFINITE POPS. MIN TEMPERATURES THROUGH MONDAY NIGHT SHOULD COOL INTO THE MID 40S IN EASTERN COLORADO TO THE MID 50S IN THE EASTERN FA. MAX TEMPERATURES MONDAY SHOULD RANGE FROM THE LOWER 60S IN EASTERN COLORADO TO THE LOWER 70S IN THE EASTERN FA. IN THE EXTENDED...(TUESDAY NIGHT THROUGH SATURDAY)...AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE CENTRAL PLAINS TUESDAY NIGHT AND WEDNESDAY AND THEN LIFT OUT OF THE AREA WEDNEDAY NIGHT. GOOD DYNAMICS AND MOISTURE SUPPORT HIGH POPS THROUGH WEDNESDAY. POPS WILL DECREASE TO CHANCE THURSDAY AND FRIDAY BEHIND THE EXITING TROUGH WITH A COUPLE OF SHORTWAVES IN SOUTHWEST FLOW PRODUCING STORMS. POPS WILL INCREASE AGAIN SATURDAY AS THE NEXT UPPER LEVEL TROUGH BEGINS IMPACTING THE CENTRAL PLAINS. MIN TEMPERATURES SHOULD RANGE FROM 45 TO 55 THROUGH FRIDAY NIGHT WITH COOLER READINGS IN EASTERN COLORADO. MAX TEMPERATURES WILL GENERALLY WARM TO THE 70S EACH DAY WITH SOME UPPER 60S POSSIBLE IN EASTERN COLORADO AND NEAR 80 IN THE EASTERN FA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1055 PM MDT SAT MAY 2 2015 VFR CONDITIONS FORECAST FOR THE 6Z TAFS. STORM ACTIVITY HAS COME TO AN END ACROSS THE TRI-STATE AREA. LIGHT WINDS WILL CONTINUE THROUGH THE REST OF THE NIGHT AND SUNDAY. DURING THE DAY A SURFACE TROUGH WILL MOVE THROUGH THE AREA CAUSING THE WINDS TO TURN CLOCKWISE THROUGH THE DAY...BECOMING NORTHEAST TO EAST BY EARLY EVENING. DURING THE EVENING STORM COVERAGE WILL INCREASE. DID NOT PLACE A MENTION IN THE TAFS AT THIS TIME SINCE THERE IS A POSSIBILITY THE STORMS WILL NOT MOVE NEAR THE SITES UNTIL AFTER 6Z...WHEN CHANCES FOR STORMS WILL INCREASE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...FS AVIATION...JTL
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1129 PM CDT Sat May 2 2015 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Sunday) Issued at 404 PM CDT SAT MAY 2 2015 19Z water vapor imagery shows a shortwave moving across IA while 500MB profiler data suggests a more subtle wave has passed through eastern KS. Meanwhile a weak mid level ridge has propagated east and is centered over the TX big bend region with the mean westerlies remain north along the Canadian boarder. At the surface, high pressure over the southeast U.S. and low pressure in the northern plains has favored continued moisture advection with southerly winds bringing mid 50s dewpoints into the central plains. For tonight and Sunday, large scale forcing continues to be absent from the pattern. However models hint at the possibility for sporadic shower activity as early as this evening. The HRRR and RAP are the most optimistic in generating the shower activity. It appears the evening QPF is driven by warm air advection and isentropic upglide around 700MB. However RAP soundings suggest moisture will be rather limited in this layer. Because of this and the general subsidence behind the subtle wave, am not convinced showers will redevelop across central KS this evening. There are also signs that another subtle wave could come out of the CO Rockies late tonight and Sunday morning with some elevated light shower activity. There is a more organized signal in the isentropic surfaces of a shallow layer of lift Sunday morning. With bases at 10 KFT and little if any instability above this layer, am not sure any precip would amount to much and it end up being mainly virga. So have maintained a dry forecast for now, but there could be some light hit or miss precip with not much impact. Thanks for the collaboration EAX and ICT. Southerly winds and increased low level moisture should help keep lows tonight around 60 degrees. Increasing clouds from the west should also help keep overnight lows mild. With continued southerly winds, models continue the warming trend at 850MB with good mixing. Therefore have maintained highs in the lower and mid 80s. However if there is elevated shower activity, the forecast may be to warm for areas that remain cloudy. .LONG TERM...(Sunday Night through Saturday) Issued at 404 PM CDT SAT MAY 2 2015 Several opportunities for precipitation remain present through the forecast, with challenges on where and when the higher chances will be being the main challenge. The main trend in the nearer periods is the trend for a farther north settling of the cold front as it enters the area. Getting the front much past the northwest counties could be difficult with little/no additional frontogenesis from convection through Sunday afternoon along it and west to southwest flow over it. Have continued to taper precip chances, especially in the south into Monday night. There continues to be at least minor potential for severe weather and perhaps training storms near the boundary. NAM continues to look overdone with low level moisture and thus CAPE, but values near 2000 J/kg seem possible along the front with flow aloft nearly parallel to the boundary with slow cell motions and PWs near 1.5", more likely late Monday into Monday night. The front/effective front remains on track to mix back north Tuesday with some drier air moving in through the day, but attention then turns to the southwest as an upper wave remains on track to push slowly northeast through the Central Plains Tuesday night through Wednesday night. Models are fairly consistent with better upper forcing to the northwest and southeast, but also with widespread convection developing to the south-southwest and translating through late Tuesday night into Wednesday. Beyond Wednesday night, there continues to be indications of a weak boundary near to just west of the area with continued moisture availability into the area into Saturday. && .AVIATION...(For the 06Z TAFs through 06Z Sunday Night) Issued at 1126 PM CDT SAT MAY 2 2015 VFR conditions expected through most of the taf period. There is a slight chance for showers and storms towards the end of the period, but confidence is low on timing at this point. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...65 AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1036 PM CDT MON MAY 4 2015 .UPDATE... WEAK INVERTED TROF/ELY WAVE CONTINUES ITS TREK WEST...CURRENTLY LOCATED ROUGHLY SOUTH OF THE CAMERON/VERMILION PARISH LINE. LATEST KLCH RADAR SHOWS ISLTD SHOWERS OVER THE COASTAL WATERS EAST OF CAMERON ALONG WITH A NARROW BAND MOVING WEST ACRS THE SABINE RIVER. SHOWER CHCS SHOULD DIMINISH ACRS ERN PORTIONS OF THE AREA TONIGHT...WITH A SLT TO LOW END CHC EXPECTED MAINLY ALONG AND WEST OF A LINE FROM LEESVILLE TO LAKE CHARLES. ADJUSTED POP/WX GRIDS SLIGHTLY TO INCORPORATE RECENT HRRR GUIDANCE. ALSO TWEAKED HOURLY WINDS AS WELL AS TEMP AND DEWPOINT GRIDS...ACCOUNTING FOR RECENT OBSERVATIONS. REMAINDER OF FCST IS IN OTHERWISE DECENT SHAPE AND UPDATES HAVE BEEN SENT. 24 && .PREV DISCUSSION... /ISSUED 706 PM CDT MON MAY 4 2015/ DISCUSSION... 05/00Z TAF ISSUANCE. AVIATION... ISLTD SHRA/TSRA AND BKN VFR CIGS ACCOMPANY A WEAK INVERTED TROF CROSSING SRN LA AND THE NRN GULF OF MEXICO. THIS TROF WILL CROSS THE REGION TONIGHT INTO TUESDAY MORNING...WITH THE MAIN AXIS OF CLOUDS/SHRA SHIFTING WEST. ACTIVITY EXPECTED TO DIMINISH THIS EVENING THEN INCREASE LATE TONIGHT...MAINLY NEAR LCH/BPT...AS SHOWERS OR STORMS MOVE INLAND OFF THE GULF. OTHERWISE...EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE PERIOD AT LFT/ARA/AEX WITH MVFR CIGS DEVELOPING AT LCH/BPT AFTER MIDNIGHT. SELY WINDS 5-10 KT TONIGHT WILL STRENGTHEN 10-15 KT TUESDAY MORNING WITH GUSTS TO 25 KT AT TIMES DURING THE DAY. 24 PREV DISCUSSION... /ISSUED 350 PM CDT MON MAY 4 2015/ DISCUSSION... NORTH-SOUTH ORIENTED INVERTED SFC TROF...OR EASTERLY WAVE...STRETCHES ROUGHLY ALONG THE ATCHAFALAYA RIVER AND ON OUT INTO THE CENTRAL GULF OF MEXICO AS OF 20Z. THIS FEATURE HAS ASSISTED WITH THE DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OVER PARTS OF SOUTH AND EAST CENTRAL LOUISIANA THIS AFTERNOON. THE WAVE IS PROGGED TO CONTINUE WWD TONIGHT...WITH A GENERAL DECREASE IN BOTH COVERAGE AND INTENSITY OF CONVECTION EXPECTED THIS EVENING WITH THE LOSS OF DIURNAL INSTABILITY. AN UPTICK IS LIKELY OVER THE GULF WATERS AFTER MIDNIGHT AND TWD THE EARLY MORNING HRS WITH THE MARINE DMAX...WITH THE NWD CELL MOTION LEADING TO AT LEAST SOME ACTIVITY SPREADING INLAND. POPS WERE RAISED OVER EAST TX TOMORROW AS THE WAVE ENTERS A REGION OF INCREASED UPPER DIVERGENCE AND DEEPER MSTR...WITH COVERAGE EXPECTED TO EXCEED THAT OBSERVED TODAY. PATTERN THEREAFTER MARKED BY A SW TO NE RIDGE AXIS OVERHEAD...WITH A MOIST SOUTHERLY LOW LEVEL FLOW AND SUBTLE IMPULSES EJECTING AHEAD OF A DIGGING WRN CONUS TROF. LOW END POPS...WITH A GRADIENT THAT GENERALLY DECREASES FROM WEST TO EAST...ALONG WITH SEASONAL HIGHS AND ABOVE NORMAL LOWS WILL RESULT. THE TROF IS PROGGED TO EDGE EASTWARD OVER THE WEEKEND...SLOWLY ERODING THE RIDGE ALOFT...THEN FINALLY LIFTING OUT INTO THE CENTRAL CONUS AND FLATTENING IT OUT EARLY NEXT WEEK. GLOBAL MODELS ALSO PROG A FRONTAL BOUNDARY INTO THE REGION ON SUN NIGHT INTO MON. 13 MARINE... WINDS AND SEAS WILL INCREASE TONIGHT INTO TUESDAY AS THE PRESSURE GRADIENT TIGHTENS WHILE AN EASTERLY WAVE MOVES WEST ACROSS THE NORTHERN GULF. ELEVATED WINDS AND SEAS WILL CONTINUE INTO TUESDAY NIGHT...SUBSIDING ON WEDNESDAY AS THE PRESSURE GRADIENT RELAXES. THE CHANCE OF SHOWERS WILL INCREASE AS THE EASTERLY WAVE MOVES ACROSS THE REGION TODAY AND TUESDAY. && .PRELIMINARY POINT TEMPS/POPS... AEX 82 63 81 62 / 20 10 10 10 LCH 81 67 80 66 / 10 30 30 10 LFT 80 65 81 64 / 40 10 10 10 BPT 81 68 80 69 / 10 40 50 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 1 AM CDT WEDNESDAY FOR GMZ452-455-470- 472-475. SMALL CRAFT EXERCISE CAUTION THROUGH LATE TUESDAY NIGHT FOR GMZ450. && $$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1234 PM CDT SUN MAY 3 2015 .AVIATION...HIGH PRESSURE RIDGING IN FROM JUST OFF THE CAROLINAS PROVIDING A LIGHT ANTICYCLONIC ONSHORE FLOW. MAINLY HIGH BASED FAIR WX CU WITH SOME ENHANCEMENT BETWEEN LCH AND LFT ON VISIBLE IMAGERY. SHORTWAVE ENERGY AROUND BPT AND AEX DUE PARTIALLY TO SOME UPPER DIVERGENCE AND HRRR IMPLIES ISOLD SHOWERS A POSSIBLILITY BUT WILL LEAVE OUT OF THE TAFS AS COVERAGE WOULD BE TOO SPARSE TO WORRY ABOUT. CONTINUED VFR. SWEENEY && .PREV DISCUSSION... /ISSUED 1058 AM CDT SUN MAY 3 2015/ DISCUSSION... FORECAST IS GENERALLY ON TRACK THIS MORNING. LATEST HIGH RESOLUTION MODELS POINT TWD THE POTENTIAL FOR ISOLD -RW ACROSS THE AREA IN RESPONSE TO INCREASING MSTR...A WEAK SHORTWAVE PUSHING EAST FROM TX...AND WEAK LL CONVERGENCE. SATELLITE IMAGERY AND A QUICK LOOK OUTSIDE REVEALS MOSTLY FLAT CU...THOUGH SOME VERTICAL DEPTH WAS NOTED OFF TO THE EAST/SE. KLCH/KPOE 88DS HAVE SHOWN SOME BRIEF LIGHT SHOWERS AS WELL. WITH ALL OF THIS IN MIND...INTRODUCED A LOW POP ALONG WITH ISOLATED SHOWERS TO THE FCST FOR TODAY. REMAINING GRIDS LOOK FINE WITH ONLY MINOR ADJUSTMENTS MADE. 13 PREV DISCUSSION... /ISSUED 410 AM CDT SUN MAY 3 2015/ DISCUSSION... EARLY MORNING SFC ANALYSIS SHOWS HIGH PRESSURE CENTERED OVER THE TENNESSEE VALLEY KEEPING A LOW-LEVEL SRLY FLOW IN PLACE OVER THE REGION. MEANWHILE WATER VAPOR IMAGERY SHOWS WEAK RIDGING IN PLACE FROM THE WRN GULF UP THROUGH THE SRN PLAINS. SATELLITE IMAGERY AND SFC OBS INDICATE LITTLE CLOUDINESS OVERHEAD ATTM...WHILE REGIONAL 88DS ARE ACCORDINGLY PPINE. ONE MORE DRY DAY LOOKS ON TAP FOR THE FORECAST AREA AS THE RIDGE ALOFT HOLDS FIRM. SEASONAL TEMPS IN THE LOWER 80S SHOULD BE THE RULE FOR THE AFTERNOON. OVER THE EARLY PART OF THE COMING WEEK THE NEXT PACIFIC STORM SYSTEM ALOFT MOVING ASHORE ALONG THE WEST COAST WILL GIVE A PUSH TO THE RIDGE...EVENTUALLY SHOVING IT TO THE SERN CONUS. IN THE MEANTIME A WEAK ERLY WAVE IS PROGGED TO SLIP PAST THE REGION ON MONDAY...ALLOWING FOR WIDELY SCATTERED SHOWERS OR STORMS TO DEVELOP BY AFTERNOON/EVENING. THEREAFTER SMALL POPS...MAINLY DAYTIME...LINGER THROUGH THE REMAINDER OF THE FORECAST AS THE PACIFIC SYSTEM GRADUALLY OPENS AND LIFTS THROUGH THE WRN CONUS AND PLAINS STATES...USHERING IN A SERIES OF WEAK DISTURBANCES ACROSS THE WRN GULF STATES. MARINE... AN ONSHORE FLOW...THOUGH SOMETIMES MORE ERLY...WILL LINGER THROUGH THE PERIOD WITH HIGH PRESSURE CENTERED OVER THE SERN CONUS AND OFF THE SRN ATLANTIC COAST. A TIGHTENING GRADIENT WITH LOW PRESSURE DEVELOPING OVER THE SRN PLAINS WILL ALLOW FOR AT LEAST CAUTION-CRITERIA WINDS BY LATE TUESDAY. && .PRELIMINARY POINT TEMPS/POPS... AEX 82 58 82 63 / 20 10 20 10 LCH 81 61 82 66 / 20 0 20 20 LFT 82 61 81 64 / 20 10 30 20 BPT 83 63 83 67 / 20 0 10 20 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$ AVIATION...11
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
340 PM EDT SUN MAY 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN MAY 3 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW MID/UPPER LEVEL TROUGH OVER WRN CANADA...FROM BC INTO NW ONTARIO. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW WAS LIFTING NE FROM FAR NW ONTARIO TO TOWARD HUDSON BAY WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING INTO SRN MANITOBA. AT THE SFC...SSW FLOW WAS INCREASING THROUGH THE UPPER MS VALLEY INTO THE WRN LAKES AHEAD OF A COLD FRONT STRETCHING FROM NW MN INTO ERN SD. SCT SHRA AND ISOLD TSRA HAD DEVELOPED AHEAD OF THE FRONT OVER CNTRL INTO NE MN WITH FAVORABLE 925 MB THETA-E ADVECTION. UPSTREAM DEWPOINTS FROM MN INTO NW WI HAD CLIMBED TO AROUND 50. A SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL SLIDE THROUGH THE NRN GREAT LAKES LATE THIS AFTERNOON AND TONIGHT. MOISTURE IS EXPECTED TO INCREASE AHEAD OF THE FRONT WITH 850 MB DEWPOINTS NEAR 10C...SFC DEWPOINTS INTO THE LOWER 50S AND PWAT VALUES TO AROUND 1.25 INCH. EVEN WITH INCREASING CLOUDS...WAA WILL HELP PUSH TEMPS INTO THE MID TO UPPER 70S OVER THE WEST HALF. THE COMBINATION OF WEAK TO MODERATE 700-500 MB QVECTOR CONV AHEAD OF THE SHRTWV AND LOW LEVEL CONV ALONG AND AHEAD OF THE FRONT WILL SUPPORT SCT/NUMEROUS SHRA/TSRA INTO THE WEST HALF OF UPPER MI BY MID TO LATE SUN AFTERNOON AND ACROSS THE REST OF THE CWA SUN EVENING. LAKE BREEZE BOUNDARIES WILL ALSO PROVIDE A FOCUS FOR TSRA DEVELOPMENT. MLCAPE LIKELY TO AROUND 1K J/KG DURING PEAK AFTERNOON HEATING ALONG WITH 0-6KM SHEAR OF 30-35KT AND WBZERO HEIGHTS OF 9K- 10K FT MAY BE ENOUGH TO SUPPORT SOME ISOLD SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL...MAINLY OVER THE SW CWA WHERE THE INSTABILITY IS EXPECTED TO GREATEST. THERE IS STILL SOME UNCERTAINTY WITH THE SEVERE RISK INTO UPPER MICHIGAN AS NAM REMAINS MORE AGGRESSIVE WITH THE AMOUNT OF MLCAPE AVAILABLE COMPARED TO THE ECMWF/GFS/GEM WHICH KEEP THE GREATER MOISTURE/INSTABILITY FARTHER SOUTH. EXPECT MOST OF THE SHRA/TSRA TO MOVE SOUTH AND EAST OF THE CWA BY 06Z WITH SOME LINGERING PCPN OVER THE FAR S AND E LATE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 300 PM EDT SUN MAY 3 2015 THE MODELS INDICATE THAT THE NRN STREAM ZONAL FLOW WILL GIVE WAY TO RIDGING OVER THE WRN GREAT LAKES DOWNSTREAM FROM A TROUGH DEVELOPING OVER THE WRN CONUS. BY LATE IN THE WEEK...SHORTWAVES EMERGING FROM THE SW CONUS AND CNTRL PLAINS WILL HELP TO FLATTEN THE RIDGE AND BRING AN INCREASING POTENTIAL FOR PCPN INTO THE WRN GREAT LAKES. TEMPS ARE EXPECTED TO REMAIN ABOVE NORMAL THROUGH MUCH OF THE PERIOD. HIGH PRES WILL DOMIMATE KEEPING CONDITIONS DRY MON NIGHT THROUGH TUE. WITH PWATS DROPPING DOWN BLO .25 INCH AND LIGHT WINDS EXPECTED UNDER THE SFC HIGH...MIN TEMPS MON NIGHT COULD VERY WELL DROP BELOW FREEZING AT SEVERAL OF THE TYPICAL INLAND COLD SPOTS. EXPECT TEMPS TO REBOUND ON TUESDAY AND MAYBE BE A FEW DEGREES WARMER THAN MONDAY/S READINGS...WITH HIGHS IN THE 60S AND LOWER 70S...WARMEST WEST. COOLER READINGS IN THE 50S CAN BE EXPECTED NEAR THE GREAT LAKES...ESPECIALLY NEAR LAKE MICHIGAN WITH DEVELOPING LIGHT SE FLOW ON BACKSIDE OF SFC RIDGE AXIS. TUE NIGHT-WED NIGHT...INCLUDED SOME LOW POPS FOR SHRA OVER MAINLY WEST HALF (ESPECIALLY ALONG THE WI BORDER) WHICH MAY DEVELOP LATE TUE NIGHT INTO WED ALONG AN 850 MB WARM FRONT LIFTING SLOWLY NNE FROM THE UPPER MS VALLEY AND AHEAD OF A STRENGTHENING 850 MB JET NOSING INTO THE WRN GREAT LAKES. TEMPS WILL BEGIN TO INCREASE WED WITH WAA BUT THERE COULD BE SOME WAA CLOUDS AROUND TO KEEP TEMPS DOWN A BIT. MODELS SUGGEST A LULL IN PCPN WED NIGHT AS 850 MB WARM FRONT LIFTS NORTH OF THE AREA AND WRN GREAT LAKES REGION BECOMES CAPPED BY WARMER/DRIER AIR ALOFT. THU-FRI...TEMPS SHOULD REALLY CLIMB THU ALONG WITH INCREASING GULF MOISTURE IN STRENGTHENING SRLY FLOW AHEAD OF A PLAINS SFC TROUGH THAT WILL EDGE TOWARD THE UPPER MS VALLEY. LAYER PWATS INCREASE FROM NEAR 1.5 INCHES WEST TO 1.25 INCHES EAST. MODELS STILL DIFFER ON TIMING OF COLD FRONTAL PASSAGE LATE IN THE WEEK WITH THE 00Z ECMWF 12-18 HRS FASTER THAN EITHER THE 12Z GFS OR 12Z CANADIAN MODEL. 00Z ECMWF HAS FRONT MOVING THROUGH LATE THU NIGHT AND FRI WHILE THE 12Z GFS/CANADIAN SHOW A FRONTAL TIMING OF FRI ATFERNOON AND FRI NIGHT. ALL MODELS SHOW INCREASING PCPN CHANCES OVER THE WEST HALF THU AFTERNOON SPREADING INTO THE EAST HALF THU NIGHT AHEAD OF APPROACHING FRONTAL BOUNDARY. MOST OF THE MODELS SHOW SHRA/TSRA HANGING AROUND ON FRIDAY WITH ECMWF SHOWING FRONTAL PASSAGE TAKING PLACE AND GFS/CANADIAN SHOWING FRONTAL BOUNDARY APPROACHING THE WRN CWA. FRI NIGHT-SATURDAY...MODEL DIFFERENCES WILL HAVE BIGGEST IMPACT ON FCST TOWARD NEXT WEEKEND. IF 00Z ECMWF VERIFIES THEN FRI NIGHT AND SAT WILL BE MOSTLY DRY AND COOLER IN WAKE OF FRONTAL PASSAGE. THE 12Z SLOWER GFS AND CANADIAN SOLN WITH FRONT WOULD WARRANT KEEPING SHRA/TSRA CHCS IN FOR AT LEAST THE CENTRAL AND ERN FCST AREA FRI NIGHT AND MAYBE EVEN LINGERING INTO SAT MORNING. GFS AND CANADIAN WOULD THEN ARGUE FOR DRIER/COOLER CONDITIONS SAT AFTERNOON INTO SAT NIGHT AS HIGH PRES BUILDS IN FM THE NW IN THE WAKE OF THE FRONTAL PASSAGE. GIVEN POOR MODEL AGREEMENT WILL PROBABLY EMPLOY A BLEND OF FCST GUIDANCE FOR POPS DURING THIS PERIOD. NEXT SUNDAY...AGAIN MODEL DIFFERENCES WILL PROBABLY ARGUE FOR USING A BLEND OF MODEL GUIDANCE BY DAY 7 FCST. THIS WOULD WARRANT A DRY FCST FOR MUCH OF THE CWA ESPECIALLY CENTRAL AND EAST STILL UNDER INFLUENCE OF CANADIAN HIGH PRES OVER AREA. THE ECMWF SHOWS SYSTEM DEVELOPING OVER CENTRAL PLAINS AND TRIES TO DEVELOP PCPN ALONG THE WI BORDER COUNTIES IN STRENGTHENING WAA PATTERN OUT AHEAD OF IT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 151 PM EDT SUN MAY 3 2015 EXPECT MAINLY VFR CEILINGS/VIS THROUGH THE PERIOD. THE ONLY EXCEPTION WILL BE IF AND WHEN TS ENTER THE AREA. SHOWERS AND ISOLATED TS ACTIVITY ACROSS CENTRAL MN WILL CONTINUE TO EDGE NE...WITH ADDITIONAL SHOWERS AND TS DEVELOPMENT ALONG THE NEARING COLD FRONT STRETCHING FROM SE ACROSS CENTRAL MANITOBA TO NEAR THE W LAKE SUPERIOR SHORELINE...AND THROUGH CENTRAL MN. LOOK FOR THE BEST CHANCE FOR TS DEVELOPMENT AT IWD 20-22Z. WHILE SAW WILL HAVE A CHANCE OF TS AROUND 23Z...IT WAS LESS LIKELY...SO LEFT VCTS OUT OF THE TAF FOR THEM. DRY HIGH PRESSURE ROLLING INTO E MT AND THE DAKOTAS THIS AFTERNOON WILL QUICKLY BUILD IN BEHIND THE FRONT. THE RESULT WILL BE A CLEAR/MOSTLY CLEAR BY DAYBREAK MONDAY IF NOT EARLIER. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 339 PM EDT SUN MAY 3 2015 OUTSIDE OF ANY THUNDERSTORM ACTIVITY...WINDS ACROSS LAKE SUPERIOR SHOULD BE AROUND 25KTS OR LESS THROUGH THE PERIOD. A LOW OVER S HUDSON BAY WILL MOVE INTO FAR N QUEBEC TONIGHT AND DRAG A TROUGH/COLD FRONT OVER LAKE SUPERIOR...WITH SHOWER AND THUNDERSTORMS...AND THE POTENTIAL FOR AREAS OF FOG. FOG WILL LINGER INTO MONDAY OVER THE E HALF OF LAKE SUPERIOR. IN THE WAKE OF THE TROUGH...HIGH PRESSURE WILL BUILD OVER THE UPPER LAKES FROM THE W-NW ON MONDAY. EXPECT THIS HIGH TO DRIFT INTO SE ONTARIO LATER TUESDAY INTO WEDNESDAY...AS ANOTHER AREA OF HIGH PRESSURE MOVES INTO NW ONTARI...AND A LOW TAKES SHAPE OVER THE PLAINS. A LOW PRESSURE CENTER EMERGING FROM THIS TROUGH WILL MOVE THROUGH THE N PLAINS ON THURSDAY WHILE THE ONTARIO HIGH DRIFTS ACROSS HUDSON BAY INTO QUEBEC. THE LOW WILL DRAG A TROUGHACROSS THE UPPER GREAT LAKES REGION THURSDAY NIGHT THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...VOSS AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
300 PM EDT SUN MAY 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN MAY 3 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW MID/UPPER LEVEL TROUGH OVER WRN CANADA...FROM BC INTO NW ONTARIO. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW WAS LIFTING NE FROM FAR NW ONTARIO TO TOWARD HUDSON BAY WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING INTO SRN MANITOBA. AT THE SFC...SSW FLOW WAS INCREASING THROUGH THE UPPER MS VALLEY INTO THE WRN LAKES AHEAD OF A COLD FRONT STRETCHING FROM NW MN INTO ERN SD. SCT SHRA AND ISOLD TSRA HAD DEVELOPED AHEAD OF THE FRONT OVER CNTRL INTO NE MN WITH FAVORABLE 925 MB THETA-E ADVECTION. UPSTREAM DEWPOINTS FROM MN INTO NW WI HAD CLIMBED TO AROUND 50. A SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL SLIDE THROUGH THE NRN GREAT LAKES LATE THIS AFTERNOON AND TONIGHT. MOISTURE IS EXPECTED TO INCREASE AHEAD OF THE FRONT WITH 850 MB DEWPOINTS NEAR 10C...SFC DEWPOINTS INTO THE LOWER 50S AND PWAT VALUES TO AROUND 1.25 INCH. EVEN WITH INCREASING CLOUDS...WAA WILL HELP PUSH TEMPS INTO THE MID TO UPPER 70S OVER THE WEST HALF. THE COMBINATION OF WEAK TO MODERATE 700-500 MB QVECTOR CONV AHEAD OF THE SHRTWV AND LOW LEVEL CONV ALONG AND AHEAD OF THE FRONT WILL SUPPORT SCT/NUMEROUS SHRA/TSRA INTO THE WEST HALF OF UPPER MI BY MID TO LATE SUN AFTERNOON AND ACROSS THE REST OF THE CWA SUN EVENING. LAKE BREEZE BOUNDARIES WILL ALSO PROVIDE A FOCUS FOR TSRA DEVELOPMENT. MLCAPE LIKELY TO AROUND 1K J/KG DURING PEAK AFTERNOON HEATING ALONG WITH 0-6KM SHEAR OF 30-35KT AND WBZERO HEIGHTS OF 9K- 10K FT MAY BE ENOUGH TO SUPPORT SOME ISOLD SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL...MAINLY OVER THE SW CWA WHERE THE INSTABILITY IS EXPECTED TO GREATEST. THERE IS STILL SOME UNCERTAINTY WITH THE SEVERE RISK INTO UPPER MICHIGAN AS NAM REMAINS MORE AGGRESSIVE WITH THE AMOUNT OF MLCAPE AVAILABLE COMPARED TO THE ECMWF/GFS/GEM WHICH KEEP THE GREATER MOISTURE/INSTABILITY FARTHER SOUTH. EXPECT MOST OF THE SHRA/TSRA TO MOVE SOUTH AND EAST OF THE CWA BY 06Z WITH SOME LINGERING PCPN OVER THE FAR S AND E LATE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 300 PM EDT SUN MAY 3 2015 THE MODELS INDICATE THAT THE NRN STREAM ZONAL FLOW WILL GIVE WAY TO RIDGING OVER THE WRN GREAT LAKES DOWNSTREAM FROM A TROUGH DEVELOPING OVER THE WRN CONUS. BY LATE IN THE WEEK...SHORTWAVES EMERGING FROM THE SW CONUS AND CNTRL PLAINS WILL HELP TO FLATTEN THE RIDGE AND BRING AN INCREASING POTENTIAL FOR PCPN INTO THE WRN GREAT LAKES. TEMPS ARE EXPECTED TO REMAIN ABOVE NORMAL THROUGH MUCH OF THE PERIOD. HIGH PRES WILL DOMIMATE KEEPING CONDITIONS DRY MON NIGHT THROUGH TUE. WITH PWATS DROPPING DOWN BLO .25 INCH AND LIGHT WINDS EXPECTED UNDER THE SFC HIGH...MIN TEMPS MON NIGHT COULD VERY WELL DROP BELOW FREEZING AT SEVERAL OF THE TYPICAL INLAND COLD SPOTS. EXPECT TEMPS TO REBOUND ON TUESDAY AND MAYBE BE A FEW DEGREES WARMER THAN MONDAY/S READINGS...WITH HIGHS IN THE 60S AND LOWER 70S...WARMEST WEST. COOLER READINGS IN THE 50S CAN BE EXPECTED NEAR THE GREAT LAKES...ESPECIALLY NEAR LAKE MICHIGAN WITH DEVELOPING LIGHT SE FLOW ON BACKSIDE OF SFC RIDGE AXIS. TUE NIGHT-WED NIGHT...INCLUDED SOME LOW POPS FOR SHRA OVER MAINLY WEST HALF (ESPECIALLY ALONG THE WI BORDER) WHICH MAY DEVELOP LATE TUE NIGHT INTO WED ALONG AN 850 MB WARM FRONT LIFTING SLOWLY NNE FROM THE UPPER MS VALLEY AND AHEAD OF A STRENGTHENING 850 MB JET NOSING INTO THE WRN GREAT LAKES. TEMPS WILL BEGIN TO INCREASE WED WITH WAA BUT THERE COULD BE SOME WAA CLOUDS AROUND TO KEEP TEMPS DOWN A BIT. MODELS SUGGEST A LULL IN PCPN WED NIGHT AS 850 MB WARM FRONT LIFTS NORTH OF THE AREA AND WRN GREAT LAKES REGION BECOMES CAPPED BY WARMER/DRIER AIR ALOFT. THU-FRI...TEMPS SHOULD REALLY CLIMB THU ALONG WITH INCREASING GULF MOISTURE IN STRENGTHENING SRLY FLOW AHEAD OF A PLAINS SFC TROUGH THAT WILL EDGE TOWARD THE UPPER MS VALLEY. LAYER PWATS INCREASE FROM NEAR 1.5 INCHES WEST TO 1.25 INCHES EAST. MODELS STILL DIFFER ON TIMING OF COLD FRONTAL PASSAGE LATE IN THE WEEK WITH THE 00Z ECMWF 12-18 HRS FASTER THAN EITHER THE 12Z GFS OR 12Z CANADIAN MODEL. 00Z ECMWF HAS FRONT MOVING THROUGH LATE THU NIGHT AND FRI WHILE THE 12Z GFS/CANADIAN SHOW A FRONTAL TIMING OF FRI ATFERNOON AND FRI NIGHT. ALL MODELS SHOW INCREASING PCPN CHANCES OVER THE WEST HALF THU AFTERNOON SPREADING INTO THE EAST HALF THU NIGHT AHEAD OF APPROACHING FRONTAL BOUNDARY. MOST OF THE MODELS SHOW SHRA/TSRA HANGING AROUND ON FRIDAY WITH ECMWF SHOWING FRONTAL PASSAGE TAKING PLACE AND GFS/CANADIAN SHOWING FRONTAL BOUNDARY APPROACHING THE WRN CWA. FRI NIGHT-SATURDAY...MODEL DIFFERENCES WILL HAVE BIGGEST IMPACT ON FCST TOWARD NEXT WEEKEND. IF 00Z ECMWF VERIFIES THEN FRI NIGHT AND SAT WILL BE MOSTLY DRY AND COOLER IN WAKE OF FRONTAL PASSAGE. THE 12Z SLOWER GFS AND CANADIAN SOLN WITH FRONT WOULD WARRANT KEEPING SHRA/TSRA CHCS IN FOR AT LEAST THE CENTRAL AND ERN FCST AREA FRI NIGHT AND MAYBE EVEN LINGERING INTO SAT MORNING. GFS AND CANADIAN WOULD THEN ARGUE FOR DRIER/COOLER CONDITIONS SAT AFTERNOON INTO SAT NIGHT AS HIGH PRES BUILDS IN FM THE NW IN THE WAKE OF THE FRONTAL PASSAGE. GIVEN POOR MODEL AGREEMENT WILL PROBABLY EMPLOY A BLEND OF FCST GUIDANCE FOR POPS DURING THIS PERIOD. NEXT SUNDAY...AGAIN MODEL DIFFERENCES WILL PROBABLY ARGUE FOR USING A BLEND OF MODEL GUIDANCE BY DAY 7 FCST. THIS WOULD WARRANT A DRY FCST FOR MUCH OF THE CWA ESPECIALLY CENTRAL AND EAST STILL UNDER INFLUENCE OF CANADIAN HIGH PRES OVER AREA. THE ECMWF SHOWS SYSTEM DEVELOPING OVER CENTRAL PLAINS AND TRIES TO DEVELOP PCPN ALONG THE WI BORDER COUNTIES IN STRENGTHENING WAA PATTERN OUT AHEAD OF IT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 151 PM EDT SUN MAY 3 2015 EXPECT MAINLY VFR CEILINGS/VIS THROUGH THE PERIOD. THE ONLY EXCEPTION WILL BE IF AND WHEN TS ENTER THE AREA. SHOWERS AND ISOLATED TS ACTIVITY ACROSS CENTRAL MN WILL CONTINUE TO EDGE NE...WITH ADDITIONAL SHOWERS AND TS DEVELOPMENT ALONG THE NEARING COLD FRONT STRETCHING FROM SE ACROSS CENTRAL MANITOBA TO NEAR THE W LAKE SUPERIOR SHORELINE...AND THROUGH CENTRAL MN. LOOK FOR THE BEST CHANCE FOR TS DEVELOPMENT AT IWD 20-22Z. WHILE SAW WILL HAVE A CHANCE OF TS AROUND 23Z...IT WAS LESS LIKELY...SO LEFT VCTS OUT OF THE TAF FOR THEM. DRY HIGH PRESSURE ROLLING INTO E MT AND THE DAKOTAS THIS AFTERNOON WILL QUICKLY BUILD IN BEHIND THE FRONT. THE RESULT WILL BE A CLEAR/MOSTLY CLEAR BY DAYBREAK MONDAY IF NOT EARLIER. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN MAY 3 2015 OUTSIDE OF ANY THUNDERSTORM ACTIVITY...WINDS ACROSS LAKE SUPERIOR SHOULD BE AROUND 25KTS OR LESS THROUGH THE PERIOD. LOW PRESSURE OVER NW ONTARIO WILL LIFT NORTHEAST TO HUDSON BAY...DRAGGING A COLD FRONT ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING ALONG WITH A CHANCE OF THUNDERSTORMS...AND PATCHY TO AREAS OF FOG. LOOK FOR HIGH PRESSURE ACROSS NORTH DAKOTA TONIGHT TO BUILD ACROSS THE UPPER GREAT LAKES MONDAY...WITH DRIER AIR LIMITING ANY LINGERING FOG ACROSS LAKE SUPERIOR. THE HIGH WILL SLOWLY EXIT ACROSS THE LOWER GREAT LAKES WEDNESDAY NIGHT...IN RESPONSE TO A LOW NEARING FROM THE N AND CENTRAL PLAINS WEDNESDAY NIGHT AND THURSDAY. THE CHANCE OF THUNDERSTORMS WILL ALSO RETURN WEDNESDAY AFTERNOON THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...VOSS AVIATION...KF MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
152 PM EDT SUN MAY 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN MAY 3 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW MID/UPPER LEVEL TROUGH OVER WRN CANADA...FROM BC INTO NW ONTARIO. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW WAS LIFTING NE FROM FAR NW ONTARIO TO TOWARD HUDSON BAY WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING INTO SRN MANITOBA. AT THE SFC...SSW FLOW WAS INCREASING THROUGH THE UPPER MS VALLEY INTO THE WRN LAKES AHEAD OF A COLD FRONT STRETCHING FROM NW MN INTO ERN SD. SCT SHRA AND ISOLD TSRA HAD DEVELOPED AHEAD OF THE FRONT OVER CNTRL INTO NE MN WITH FAVORABLE 925 MB THETA-E ADVECTION. UPSTREAM DEWPOINTS FROM MN INTO NW WI HAD CLIMBED TO AROUND 50. A SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL SLIDE THROUGH THE NRN GREAT LAKES LATE THIS AFTERNOON AND TONIGHT. MOISTURE IS EXPECTED TO INCREASE AHEAD OF THE FRONT WITH 850 MB DEWPOINTS NEAR 10C...SFC DEWPOINTS INTO THE LOWER 50S AND PWAT VALUES TO AROUND 1.25 INCH. EVEN WITH INCREASING CLOUDS...WAA WILL HELP PUSH TEMPS INTO THE MID TO UPPER 70S OVER THE WEST HALF. THE COMBINATION OF WEAK TO MODERATE 700-500 MB QVECTOR CONV AHEAD OF THE SHRTWV AND LOW LEVEL CONV ALONG AND AHEAD OF THE FRONT WILL SUPPORT SCT/NUMEROUS SHRA/TSRA INTO THE WEST HALF OF UPPER MI BY MID TO LATE SUN AFTERNOON AND ACROSS THE REST OF THE CWA SUN EVENING. LAKE BREEZE BOUNDARIES WILL ALSO PROVIDE A FOCUS FOR TSRA DEVELOPMENT. MLCAPE LIKELY TO AROUND 1K J/KG DURING PEAK AFTERNOON HEATING ALONG WITH 0-6KM SHEAR OF 30-35KT AND WBZERO HEIGHTS OF 9K- 10K FT MAY BE ENOUGH TO SUPPORT SOME ISOLD SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL...MAINLY OVER THE SW CWA WHERE THE INSTABILITY IS EXPECTED TO GREATEST. THERE IS STILL SOME UNCERTAINTY WITH THE SEVERE RISK INTO UPPER MICHIGAN AS NAM REMAINS MORE AGGRESSIVE WITH THE AMOUNT OF MLCAPE AVAILABLE COMPARED TO THE ECMWF/GFS/GEM WHICH KEEP THE GREATER MOISTURE/INSTABILITY FARTHER SOUTH. EXPECT MOST OF THE SHRA/TSRA TO MOVE SOUTH AND EAST OF THE CWA BY 06Z WITH SOME LINGERING PCPN OVER THE FAR S AND E LATE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 AM EDT SUN MAY 3 2015 ABOVE AVERAGE TEMPS WITH GENERALLY DRY CONDITIONS ARE EXPECTED ACROSS THE FORECAST AREA THROUGH TUESDAY BEFORE OFF AND ON CHANCES OF SHOWERS AND THUNDERSTORMS CLOSE OUT THE WEEK. MONDAY AND TUESDAY...A SPLIT UPPER JET PATTERN WILL BE WELL IN PLACE TO BEGIN THE PERIOD...WITH A VERY BROAD MID-LEVEL TROUGH ACROSS THE UPPER MS VALLEY AND UPPER GREAT LAKES. THE COLD FRONT AND ASSOCIATED CONVECTION EXPECTED TO INFLUENCE THE CWA THIS AFTERNOON AND TONIGHT WILL CLEAR THE CWA BY 12Z MONDAY. WITH SFC HIGH PRESSURE SHIFTING ACROSS THE CWA AND A MID-LEVEL RIDGE BUILDING ACROSS THE NORTHERN PLAINS...DRY CONDITIONS ARE EXPECTED MONDAY THROUGH TUESDAY. TEMPS WILL BE COOLER THAN TODAY FOR BOTH MONDAY AND TUESDAY AS 850 HPA TEMPS FALL TO 3-7C. WITH A WNW WIND MON...TEMPS WILL BE CHILLY ACROSS PORTIONS OF THE LAKE SUPERIOR SHORELINE...ESPECIALLY EAST OF MARQUETTE. SOME HINTS AS LINGERING LOW-LEVEL MOISTURE OVER EASTERN LAKE SUPERIOR MAY ALSO RESULT IN SOME FOG ALONG THE SHORELINE THROUGH MOST OF MONDAY. TUESDAY NIGHT AND WEDNESDAY...A BROAD SFC LOW FORMING UNDER THE SOUTHERN UPPER JET AND A MID-LEVEL TROUGH OVER THE SW STATES WILL BEGIN TO LIFT INTO THE CENTRAL PLAINS BY THIS TIME. MEANWHILE...THE MID-LEVEL RIDGE ACROSS THE PLAINS AND MS VALLEY WILL CONTINUE TO BUILD WHILE DRIFTING EASTWARD. LOW-LEVEL WAA/ISENTROPIC LIFT WELL AHEAD OF THIS LOW IS EXPECTED ACROSS WI AND THE WEST AND CENTRAL CWA TUESDAY NIGHT INTO WEDNESDAY...AND SHOULD BE ENOUGH TO GENERATE LIGHT RAIN ALOFT. HOW MUCH REACHES THE GROUND REMAINS IN QUESTION AS THE LOW-LEVELS WILL BE QUITE DRY TUESDAY. BECAUSE OF THIS...ALL MODEL SOLUTIONS SHOW A RAPID DETERIORATION OF THE PRECIP AS IT MOVES OVER UPPER MI. HAVE OPTED TO KEEP ONLY LOW CHANCE POPS ALONG THE WI BORDER TUESDAY NIGHT...AND ACROSS MUCH OF WESTERN AND CENTRAL UPPER MI ON WEDNESDAY. THURSDAY THROUGH SATURDAY...THE SFC LOW OVER THE PLAINS WILL CONTINUE TO MEANDER TO THE NE AS THE ASSOCIATED MID-LEVEL WAVE ATTEMPTS TO ROUND THE RIDGE. WITH MINIMAL FORCING...MUCH OF THE AREA SHOULD REMAIN DRY WED NIGHT INTO THU MORNING. BY THE AFTERNOON...FORCING FROM THE APPROACHING MID-LEVEL SHORTWAVE WILL BE ENOUGH TO INDUCE SCATTERED SHOWERS AND POSSIBLY SOME THUNDERSTORMS ACROSS THE WEST HALF OF THE CWA. WITH THE WAVE AND SFC LOW LIFTING ACROSS THE ARROWHEAD OF MN AND NORTH OF LAKE SUPERIOR...SCATTERED SHOWERS AND STORMS ARE EXPECTED INTO FRIDAY MORNING. COVERAGE MAY INCREASE FRIDAY AFTERNOON AS THE SFC COLD FRONT BEGINS TO MOVE IN FROM THE WEST. OVERALL...DO NOT SEE ANY REASON TO GO WITH ANYTHING HIGHER THAN HIGH-END CHANCE POPS GIVEN THE OVERALL SCATTERED NATURE OF EXPECTED PRECIP. BY SATURDAY...THE SFC COLD FRONT WILL CLEAR THE AREA AS IT BEGINS TO STALL/WASH OUT OVER WI. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 151 PM EDT SUN MAY 3 2015 EXPECT MAINLY VFR CEILINGS/VIS THROUGH THE PERIOD. THE ONLY EXCEPTION WILL BE IF AND WHEN TS ENTER THE AREA. SHOWERS AND ISOLATED TS ACTIVITY ACROSS CENTRAL MN WILL CONTINUE TO EDGE NE...WITH ADDITIONAL SHOWERS AND TS DEVELOPMENT ALONG THE NEARING COLD FRONT STRETCHING FROM SE ACROSS CENTRAL MANITOBA TO NEAR THE W LAKE SUPERIOR SHORELINE...AND THROUGH CENTRAL MN. LOOK FOR THE BEST CHANCE FOR TS DEVELOPMENT AT IWD 20-22Z. WHILE SAW WILL HAVE A CHANCE OF TS AROUND 23Z...IT WAS LESS LIKELY...SO LEFT VCTS OUT OF THE TAF FOR THEM. DRY HIGH PRESSURE ROLLING INTO E MT AND THE DAKOTAS THIS AFTERNOON WILL QUICKLY BUILD IN BEHIND THE FRONT. THE RESULT WILL BE A CLEAR/MOSTLY CLEAR BY DAYBREAK MONDAY IF NOT EARLIER. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN MAY 3 2015 OUTSIDE OF ANY THUNDERSTORM ACTIVITY...WINDS ACROSS LAKE SUPERIOR SHOULD BE AROUND 25KTS OR LESS THROUGH THE PERIOD. LOW PRESSURE OVER NW ONTARIO WILL LIFT NORTHEAST TO HUDSON BAY...DRAGGING A COLD FRONT ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING ALONG WITH A CHANCE OF THUNDERSTORMS...AND PATCHY TO AREAS OF FOG. LOOK FOR HIGH PRESSURE ACROSS NORTH DAKOTA TONIGHT TO BUILD ACROSS THE UPPER GREAT LAKES MONDAY...WITH DRIER AIR LIMITING ANY LINGERING FOG ACROSS LAKE SUPERIOR. THE HIGH WILL SLOWLY EXIT ACROSS THE LOWER GREAT LAKES WEDNESDAY NIGHT...IN RESPONSE TO A LOW NEARING FROM THE N AND CENTRAL PLAINS WEDNESDAY NIGHT AND THURSDAY. THE CHANCE OF THUNDERSTORMS WILL ALSO RETURN WEDNESDAY AFTERNOON THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...KF MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EDT SUN MAY 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN MAY 3 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW MID/UPPER LEVEL TROUGH OVER WRN CANADA...FROM BC INTO NW ONTARIO. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW WAS LIFTING NE FROM FAR NW ONTARIO TO TOWARD HUDSON BAY WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING INTO SRN MANITOBA. AT THE SFC...SSW FLOW WAS INCREASING THROUGH THE UPPER MS VALLEY INTO THE WRN LAKES AHEAD OF A COLD FRONT STRETCHING FROM NW MN INTO ERN SD. SCT SHRA AND ISOLD TSRA HAD DEVELOPED AHEAD OF THE FRONT OVER CNTRL INTO NE MN WITH FAVORABLE 925 MB THETA-E ADVECTION. UPSTREAM DEWPOINTS FROM MN INTO NW WI HAD CLIMBED TO AROUND 50. A SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL SLIDE THROUGH THE NRN GREAT LAKES LATE THIS AFTERNOON AND TONIGHT. MOISTURE IS EXPECTED TO INCREASE AHEAD OF THE FRONT WITH 850 MB DEWPOINTS NEAR 10C...SFC DEWPOINTS INTO THE LOWER 50S AND PWAT VALUES TO AROUND 1.25 INCH. EVEN WITH INCREASING CLOUDS...WAA WILL HELP PUSH TEMPS INTO THE MID TO UPPER 70S OVER THE WEST HALF. THE COMBINATION OF WEAK TO MODERATE 700-500 MB QVECTOR CONV AHEAD OF THE SHRTWV AND LOW LEVEL CONV ALONG AND AHEAD OF THE FRONT WILL SUPPORT SCT/NUMEROUS SHRA/TSRA INTO THE WEST HALF OF UPPER MI BY MID TO LATE SUN AFTERNOON AND ACROSS THE REST OF THE CWA SUN EVENING. LAKE BREEZE BOUNDARIES WILL ALSO PROVIDE A FOCUS FOR TSRA DEVELOPMENT. MLCAPE LIKELY TO AROUND 1K J/KG DURING PEAK AFTERNOON HEATING ALONG WITH 0-6KM SHEAR OF 30-35KT AND WBZERO HEIGHTS OF 9K- 10K FT MAY BE ENOUGH TO SUPPORT SOME ISOLD SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL...MAINLY OVER THE SW CWA WHERE THE INSTABILITY IS EXPECTED TO GREATEST. THERE IS STILL SOME UNCERTAINTY WITH THE SEVERE RISK INTO UPPER MICHIGAN AS NAM REMAINS MORE AGGRESSIVE WITH THE AMOUNT OF MLCAPE AVAILABLE COMPARED TO THE ECMWF/GFS/GEM WHICH KEEP THE GREATER MOISTURE/INSTABILITY FARTHER SOUTH. EXPECT MOST OF THE SHRA/TSRA TO MOVE SOUTH AND EAST OF THE CWA BY 06Z WITH SOME LINGERING PCPN OVER THE FAR S AND E LATE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 AM EDT SUN MAY 3 2015 ABOVE AVERAGE TEMPS WITH GENERALLY DRY CONDITIONS ARE EXPECTED ACROSS THE FORECAST AREA THROUGH TUESDAY BEFORE OFF AND ON CHANCES OF SHOWERS AND THUNDERSTORMS CLOSE OUT THE WEEK. MONDAY AND TUESDAY...A SPLIT UPPER JET PATTERN WILL BE WELL IN PLACE TO BEGIN THE PERIOD...WITH A VERY BROAD MID-LEVEL TROUGH ACROSS THE UPPER MS VALLEY AND UPPER GREAT LAKES. THE COLD FRONT AND ASSOCIATED CONVECTION EXPECTED TO INFLUENCE THE CWA THIS AFTERNOON AND TONIGHT WILL CLEAR THE CWA BY 12Z MONDAY. WITH SFC HIGH PRESSURE SHIFTING ACROSS THE CWA AND A MID-LEVEL RIDGE BUILDING ACROSS THE NORTHERN PLAINS...DRY CONDITIONS ARE EXPECTED MONDAY THROUGH TUESDAY. TEMPS WILL BE COOLER THAN TODAY FOR BOTH MONDAY AND TUESDAY AS 850 HPA TEMPS FALL TO 3-7C. WITH A WNW WIND MON...TEMPS WILL BE CHILLY ACROSS PORTIONS OF THE LAKE SUPERIOR SHORELINE...ESPECIALLY EAST OF MARQUETTE. SOME HINTS AS LINGERING LOW-LEVEL MOISTURE OVER EASTERN LAKE SUPERIOR MAY ALSO RESULT IN SOME FOG ALONG THE SHORELINE THROUGH MOST OF MONDAY. TUESDAY NIGHT AND WEDNESDAY...A BROAD SFC LOW FORMING UNDER THE SOUTHERN UPPER JET AND A MID-LEVEL TROUGH OVER THE SW STATES WILL BEGIN TO LIFT INTO THE CENTRAL PLAINS BY THIS TIME. MEANWHILE...THE MID-LEVEL RIDGE ACROSS THE PLAINS AND MS VALLEY WILL CONTINUE TO BUILD WHILE DRIFTING EASTWARD. LOW-LEVEL WAA/ISENTROPIC LIFT WELL AHEAD OF THIS LOW IS EXPECTED ACROSS WI AND THE WEST AND CENTRAL CWA TUESDAY NIGHT INTO WEDNESDAY...AND SHOULD BE ENOUGH TO GENERATE LIGHT RAIN ALOFT. HOW MUCH REACHES THE GROUND REMAINS IN QUESTION AS THE LOW-LEVELS WILL BE QUITE DRY TUESDAY. BECAUSE OF THIS...ALL MODEL SOLUTIONS SHOW A RAPID DETERIORATION OF THE PRECIP AS IT MOVES OVER UPPER MI. HAVE OPTED TO KEEP ONLY LOW CHANCE POPS ALONG THE WI BORDER TUESDAY NIGHT...AND ACROSS MUCH OF WESTERN AND CENTRAL UPPER MI ON WEDNESDAY. THURSDAY THROUGH SATURDAY...THE SFC LOW OVER THE PLAINS WILL CONTINUE TO MEANDER TO THE NE AS THE ASSOCIATED MID-LEVEL WAVE ATTEMPTS TO ROUND THE RIDGE. WITH MINIMAL FORCING...MUCH OF THE AREA SHOULD REMAIN DRY WED NIGHT INTO THU MORNING. BY THE AFTERNOON...FORCING FROM THE APPROACHING MID-LEVEL SHORTWAVE WILL BE ENOUGH TO INDUCE SCATTERED SHOWERS AND POSSIBLY SOME THUNDERSTORMS ACROSS THE WEST HALF OF THE CWA. WITH THE WAVE AND SFC LOW LIFTING ACROSS THE ARROWHEAD OF MN AND NORTH OF LAKE SUPERIOR...SCATTERED SHOWERS AND STORMS ARE EXPECTED INTO FRIDAY MORNING. COVERAGE MAY INCREASE FRIDAY AFTERNOON AS THE SFC COLD FRONT BEGINS TO MOVE IN FROM THE WEST. OVERALL...DO NOT SEE ANY REASON TO GO WITH ANYTHING HIGHER THAN HIGH-END CHANCE POPS GIVEN THE OVERALL SCATTERED NATURE OF EXPECTED PRECIP. BY SATURDAY...THE SFC COLD FRONT WILL CLEAR THE AREA AS IT BEGINS TO STALL/WASH OUT OVER WI. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 740 AM EDT SUN MAY 3 2015 EXPECT VFR CONDITIONS THROUGH THIS MORNING AT ALL THE TAF SITES WITH RELATIVELY DRY AIRMASS ASSOCIATED WITH RETREATING HIGH PRES DOMINATING. DURING THE AFTERNOON...THE INTERACTION BETWEEN AN APPROACHING DISTURBANCE/COLD FRONT...INCREASING LOW LEVEL MOISTURE IN A GUSTY SW FLOW AHEAD OF THE FRONT AND DAYTIME HEATING/DESTABILIZATION WILL RESULT IN SOME SHRA AND TSRA. THERE IS STILL SOME UNCERTAINTY ON THE DEGREE OF LOW LEVEL MOISTENING/DESTABILIZATION...BUT DID INCLUDE A MENTION OF SOME TS AT SAW...WHICH IS MORE LIKELY TO SEE HIGHER INSTABILITY. MVFR CONDITIONS ARE LIKELY TO ACCOMPANY THE STRONGER SHRA/TS. ANY STRONGER TS COULD ALSO PRODUCE VERY GUSTY WINDS. LOOK FOR VFR CONDITIONS OVERNIGHT WITH DRYING BEHIND THE COLD FRONT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN MAY 3 2015 OUTSIDE OF ANY THUNDERSTORM ACTIVITY...WINDS ACROSS LAKE SUPERIOR SHOULD BE AROUND 25KTS OR LESS THROUGH THE PERIOD. LOW PRESSURE OVER NW ONTARIO WILL LIFT NORTHEAST TO HUDSON BAY...DRAGGING A COLD FRONT ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING ALONG WITH A CHANCE OF THUNDERSTORMS...AND PATCHY TO AREAS OF FOG. LOOK FOR HIGH PRESSURE ACROSS NORTH DAKOTA TONIGHT TO BUILD ACROSS THE UPPER GREAT LAKES MONDAY...WITH DRIER AIR LIMITING ANY LINGERING FOG ACROSS LAKE SUPERIOR. THE HIGH WILL SLOWLY EXIT ACROSS THE LOWER GREAT LAKES WEDNESDAY NIGHT...IN RESPONSE TO A LOW NEARING FROM THE N AND CENTRAL PLAINS WEDNESDAY NIGHT AND THURSDAY. THE CHANCE OF THUNDERSTORMS WILL ALSO RETURN WEDNESDAY AFTERNOON THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
507 AM EDT SUN MAY 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN MAY 3 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD SHALLOW MID/UPPER LEVEL TROUGH OVER WRN CANADA...FROM BC INTO NW ONTARIO. A SHORTWAVE TROUGH AND ASSOCIATED SFC LOW WAS LIFTING NE FROM FAR NW ONTARIO TO TOWARD HUDSON BAY WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING INTO SRN MANITOBA. AT THE SFC...SSW FLOW WAS INCREASING THROUGH THE UPPER MS VALLEY INTO THE WRN LAKES AHEAD OF A COLD FRONT STRETCHING FROM NW MN INTO ERN SD. SCT SHRA AND ISOLD TSRA HAD DEVELOPED AHEAD OF THE FRONT OVER CNTRL INTO NE MN WITH FAVORABLE 925 MB THETA-E ADVECTION. UPSTREAM DEWPOINTS FROM MN INTO NW WI HAD CLIMBED TO AROUND 50. A SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL SLIDE THROUGH THE NRN GREAT LAKES LATE THIS AFTERNOON AND TONIGHT. MOISTURE IS EXPECTED TO INCREASE AHEAD OF THE FRONT WITH 850 MB DEWPOINTS NEAR 10C...SFC DEWPOINTS INTO THE LOWER 50S AND PWAT VALUES TO AROUND 1.25 INCH. EVEN WITH INCREASING CLOUDS...WAA WILL HELP PUSH TEMPS INTO THE MID TO UPPER 70S OVER THE WEST HALF. THE COMBINATION OF WEAK TO MODERATE 700-500 MB QVECTOR CONV AHEAD OF THE SHRTWV AND LOW LEVEL CONV ALONG AND AHEAD OF THE FRONT WILL SUPPORT SCT/NUMEROUS SHRA/TSRA INTO THE WEST HALF OF UPPER MI BY MID TO LATE SUN AFTERNOON AND ACROSS THE REST OF THE CWA SUN EVENING. LAKE BREEZE BOUNDARIES WILL ALSO PROVIDE A FOCUS FOR TSRA DEVELOPMENT. MLCAPE LIKELY TO AROUND 1K J/KG DURING PEAK AFTERNOON HEATING ALONG WITH 0-6KM SHEAR OF 30-35KT AND WBZERO HEIGHTS OF 9K- 10K FT MAY BE ENOUGH TO SUPPORT SOME ISOLD SEVERE STORMS WITH DAMAGING WINDS AND LARGE HAIL...MAINLY OVER THE SW CWA WHERE THE INSTABILITY IS EXPECTED TO GREATEST. THERE IS STILL SOME UNCERTAINTY WITH THE SEVERE RISK INTO UPPER MICHIGAN AS NAM REMAINS MORE AGGRESSIVE WITH THE AMOUNT OF MLCAPE AVAILABLE COMPARED TO THE ECMWF/GFS/GEM WHICH KEEP THE GREATER MOISTURE/INSTABILITY FARTHER SOUTH. EXPECT MOST OF THE SHRA/TSRA TO MOVE SOUTH AND EAST OF THE CWA BY 06Z WITH SOME LINGERING PCPN OVER THE FAR S AND E LATE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 AM EDT SUN MAY 3 2015 ABOVE AVERAGE TEMPS WITH GENERALLY DRY CONDITIONS ARE EXPECTED ACROSS THE FORECAST AREA THROUGH TUESDAY BEFORE OFF AND ON CHANCES OF SHOWERS AND THUNDERSTORMS CLOSE OUT THE WEEK. MONDAY AND TUESDAY...A SPLIT UPPER JET PATTERN WILL BE WELL IN PLACE TO BEGIN THE PERIOD...WITH A VERY BROAD MID-LEVEL TROUGH ACROSS THE UPPER MS VALLEY AND UPPER GREAT LAKES. THE COLD FRONT AND ASSOCIATED CONVECTION EXPECTED TO INFLUENCE THE CWA THIS AFTERNOON AND TONIGHT WILL CLEAR THE CWA BY 12Z MONDAY. WITH SFC HIGH PRESSURE SHIFTING ACROSS THE CWA AND A MID-LEVEL RIDGE BUILDING ACROSS THE NORTHERN PLAINS...DRY CONDITIONS ARE EXPECTED MONDAY THROUGH TUESDAY. TEMPS WILL BE COOLER THAN TODAY FOR BOTH MONDAY AND TUESDAY AS 850 HPA TEMPS FALL TO 3-7C. WITH A WNW WIND MON...TEMPS WILL BE CHILLY ACROSS PORTIONS OF THE LAKE SUPERIOR SHORELINE...ESPECIALLY EAST OF MARQUETTE. SOME HINTS AS LINGERING LOW-LEVEL MOISTURE OVER EASTERN LAKE SUPERIOR MAY ALSO RESULT IN SOME FOG ALONG THE SHORELINE THROUGH MOST OF MONDAY. TUESDAY NIGHT AND WEDNESDAY...A BROAD SFC LOW FORMING UNDER THE SOUTHERN UPPER JET AND A MID-LEVEL TROUGH OVER THE SW STATES WILL BEGIN TO LIFT INTO THE CENTRAL PLAINS BY THIS TIME. MEANWHILE...THE MID-LEVEL RIDGE ACROSS THE PLAINS AND MS VALLEY WILL CONTINUE TO BUILD WHILE DRIFTING EASTWARD. LOW-LEVEL WAA/ISENTROPIC LIFT WELL AHEAD OF THIS LOW IS EXPECTED ACROSS WI AND THE WEST AND CENTRAL CWA TUESDAY NIGHT INTO WEDNESDAY...AND SHOULD BE ENOUGH TO GENERATE LIGHT RAIN ALOFT. HOW MUCH REACHES THE GROUND REMAINS IN QUESTION AS THE LOW-LEVELS WILL BE QUITE DRY TUESDAY. BECAUSE OF THIS...ALL MODEL SOLUTIONS SHOW A RAPID DETERIORATION OF THE PRECIP AS IT MOVES OVER UPPER MI. HAVE OPTED TO KEEP ONLY LOW CHANCE POPS ALONG THE WI BORDER TUESDAY NIGHT...AND ACROSS MUCH OF WESTERN AND CENTRAL UPPER MI ON WEDNESDAY. THURSDAY THROUGH SATURDAY...THE SFC LOW OVER THE PLAINS WILL CONTINUE TO MEANDER TO THE NE AS THE ASSOCIATED MID-LEVEL WAVE ATTEMPTS TO ROUND THE RIDGE. WITH MINIMAL FORCING...MUCH OF THE AREA SHOULD REMAIN DRY WED NIGHT INTO THU MORNING. BY THE AFTERNOON...FORCING FROM THE APPROACHING MID-LEVEL SHORTWAVE WILL BE ENOUGH TO INDUCE SCATTERED SHOWERS AND POSSIBLY SOME THUNDERSTORMS ACROSS THE WEST HALF OF THE CWA. WITH THE WAVE AND SFC LOW LIFTING ACROSS THE ARROWHEAD OF MN AND NORTH OF LAKE SUPERIOR...SCATTERED SHOWERS AND STORMS ARE EXPECTED INTO FRIDAY MORNING. COVERAGE MAY INCREASE FRIDAY AFTERNOON AS THE SFC COLD FRONT BEGINS TO MOVE IN FROM THE WEST. OVERALL...DO NOT SEE ANY REASON TO GO WITH ANYTHING HIGHER THAN HIGH-END CHANCE POPS GIVEN THE OVERALL SCATTERED NATURE OF EXPECTED PRECIP. BY SATURDAY...THE SFC COLD FRONT WILL CLEAR THE AREA AS IT BEGINS TO STALL/WASH OUT OVER WI. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 125 AM EDT SUN MAY 3 2015 EXPECT VFR CONDITIONS THRU THIS MRNG AT ALL THE TAF SITES WITH RELATIVELY DRY AIRMASS ASSOCIATED WITH RETREATING HI PRES DOMINATING. DURING THE AFTN...THE INTERACTION BTWN AN APRCHG DISTURBANCE/COLD FNT...INCRSG LLVL ABSOLUTE MSTR IN A GUSTY SW FLOW AHEAD OF THE FNT AND DAYTIME HEATING/DESTABILIZATION WL RESULT IN SOME SHRA AND TS. THERE IS STILL SOME UNCERTAINTY ON THE DEGREE OF LLVL MOISTENING/DESTABILIZATION...BUT DID INCLUDE A MENTION OF SOME TS AT SAW...WHICH IS MORE LIKELY TO SEE SUFFICIENT MOISTENING. MVFR CONDITIONS ARE LIKELY TO ACCOMPANY THE STRONGER SHRA/TS. ANY STRONGER TS COULD ALSO PRODUCE VERY GUSTY WINDS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN MAY 3 2015 OUTSIDE OF ANY THUNDERSTORM ACTIVITY...WINDS ACROSS LAKE SUPERIOR SHOULD BE AROUND 25KTS OR LESS THROUGH THE PERIOD. LOW PRESSURE OVER NW ONTARIO WILL LIFT NORTHEAST TO HUDSON BAY...DRAGGING A COLD FRONT ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING ALONG WITH A CHANCE OF THUNDERSTORMS...AND PATCHY TO AREAS OF FOG. LOOK FOR HIGH PRESSURE ACROSS NORTH DAKOTA TONIGHT TO BUILD ACROSS THE UPPER GREAT LAKES MONDAY...WITH DRIER AIR LIMITING ANY LINGERING FOG ACROSS LAKE SUPERIOR. THE HIGH WILL SLOWLY EXIT ACROSS THE LOWER GREAT LAKES WEDNESDAY NIGHT...IN RESPONSE TO A LOW NEARING FROM THE N AND CENTRAL PLAINS WEDNESDAY NIGHT AND THURSDAY. THE CHANCE OF THUNDERSTORMS WILL ALSO RETURN WEDNESDAY AFTERNOON THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1216 AM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 940 PM CDT SAT MAY 2 2015 THE DECAYING LINE OF SHOWERS AND THUNDERSTORMS CONTINUED TO DIMINISH AS IT MOVES EASTWARD INTO THE CWA DURING THE EVENING. SOME GUSTY WINDS REMAINED ACROSS AREAS WEST OF THE BRAINERD LAKES REGION...ALTHOUGH WIND SPEED VALUES HAVE DECREASED CONSIDERABLY. COULD STILL BE SOME GUSTY WINDS...MAINLY ACROSS THE BRAINERD LAKES AND LEECH LAKE AREAS DURING THE REMAINDER OF THE EVENING. OVERALL...THINK THINGS WILL QUIET DOWN FURTHER AS THE NIGHT WEARS ON...PER HRRR AND RAP SIMULATED REFLECTIVITY AS WELL AS THE 4KM NMM WRF. WILL CONTINUE ISOLATED TO SCATTERED MENTION FOR MUCH OF THE AREA AS THE NIGHT WEARS ON. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 324 PM CDT SAT MAY 2 2015 A SFC LOW WAS MOVING INTO NW ONTARIO AT 19Z WITH A TRAILING COLD FRONT SWWD INTO WESTERN ND. A SFC TROF WAS ALSO FOUND IN CENTRAL ND. THUNDERSTORMS WERE FIRING AHEAD OF THIS TROF IN THE VCNTY OF EMBEDDED PIECES OF ENERGY IN FAST ZONAL FLOW ALOFT. AN AREA OF SFC FGEN WAS ALSO CO-LOCATED WITH THE STORMS. EXPECT THIS LINE OF STORMS TO REACH NW MN BY 21Z. THE STORMS WILL CONTINUE TO MOVE EWD AND REACH THE NW CORNER OF KOOCHICHING COUNTY BY 01Z. HOWEVER...IT IS AT THIS POINT IN TIME WHEN THE STORMS BEGIN TO ENCOUNTER DRIER AIR THAT HAS BEEN CAMPED OUT OVER THE FORECAST AREA. LATEST SHORT TERM HIRES MODELS INCLUDING THE HRRR AND RAP SHOW THIS TREND AS WELL. AS THIS INITIAL ROUND OF STORMS DISSOLVES...THE NEXT ROUND WILL BEGIN TO DEVELOP OVER THE WESTERN HALF OF THE AREA AROUND 06Z AS THE SFC FRONT MAKES PROGRESS EWD INTO THE REGION. A LOW LEVEL INVERSION SEEN ON AREA FORECAST SOUNDINGS INDICATE THAT THESE STORMS WILL BE ELEVATED IN NATURE. ON SUNDAY...THE FRONT WILL PROGRESS SLOWLY EWD THROUGH THE DAY. SOME WEAK THUNDERSTORMS WILL BE AROUND IN THE MORNING AS A THERMAL RIDGE AXIS IS OVER THE REGION AND INSTABILITY IS WEAK. BY AFTERNOON...THE FRONT PUSHES INTO NW WI WITH MAX HEATING...STORMS WILL BECOME A BIT MORE VIGOROUS...AND BORDER ON SEVERE. SBCAPE INCREASES TO NEAR 3000 J/KG AND LI/S TO -8C PER FORECAST SOUNDINGS. SHOULD SEE SOME STORMS NEAR SEVERE WITH LARGE HAIL AND BRIEF HEAVY RAIN AS PWATS ARE 1 TO 1.25 INCHES. MODELS COME INTO AGREEMENT WITH THIS SOLUTION AND HAVE ROBUST QPF BY 00Z MONDAY. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 324 PM CDT SAT MAY 2 2015 SUNDAY EVENING THE COLD FRONT MOVES SOUTHEAST AWAY FROM THE AREA...AND WHILE I HAVE MAINTAINED SOME POPS FOR THE EVENING HOURS...EXPECT THEY WILL ONLY BE ONGOING AT THE VERY BEGINNING OF THE PERIOD AND EXIT QUICKLY DURING THE EVENING. A COOLER AND DRIER AIRMASS MOVES INTO THE AREA AFTER MIDNIGHT AND WILL LINGER THROUGH MONDAY AND MONDAY NIGHT. LOWS SUNDAY NIGHT AND MONDAY NIGHT TO FALL INTO THE MID 30S TO MID 40S FOR MUCH OF THE AREA...WITH HIGHS MONDAY BACK IN THE 60S TO AROUND 70. THE UPPER LEVEL PATTERN IS EXPECTED TO SHIFT TO A LONGWAVE TROUGH OVER THE WEST COAST AND ROCKIES...WITH WEAK RIDGING TO ZONAL FLOW OVER THE EASTERN CONUS. THIS TROUGHINESS TO OUR WEST IS GOING TO SENT A STRONG...SLOW MOVING UPPER LEVEL LOW SHORTWAVE ACROSS THE UPPER MIDWEST TUESDAY THROUGH FRIDAY...WITH SOME FAIRLY HIGH CHANCES FOR PRECIPITATION DURING THE PERIOD. TEMPERATURES WILL ALSO BE ABOVE NORMAL WITH HIGHS IN THE 70S EVEN WITH INCREASED CLOUD COVER AND PRECIPITATION. THIS SYSTEM TO MOVE OFF TO THE NORTHEAST BY SATURDAY...BUT THE UPPER LEVEL PATTERN OF A TROUGH OUT WEST REMAINS WITH WARM AIR STILL BEING FUNNELED IN OUR DIRECTION AND SOME LINGERING PRECIPITATION CHANCES INTO THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1212 AM CDT SUN MAY 3 2015 A COLD FRONT WILL MOVE EASTWARD ACROSS THE NORTHLAND ON SUNDAY. ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO BE FOUND ACROSS THE AREA OVERNIGHT...AS INCREASINGLY UNSTABLE AIR DEVELOPS ACROSS THE REGION INTO SUNDAY. THE COLD FRONT SHOULD REACH A KBRD TO KCDD LINE BY 15Z SUNDAY...AND KSTC TO NEAR KDLH LINE BY 18Z. THE FRONT WILL BE THE CATALYST FOR STRONG THUNDERSTORM DEVELOPMENT ON SUNDAY... WITH STORMS EXPECTED TO FIRE UP FROM EAST CENTRAL MINNESOTA INTO KDLH AND THE NORTH SHORE BY MIDDAY. THE BEST CHANCE FOR STORMS WILL BE IN WISCONSIN...ESPECIALLY FOR KHYR AND AREAS TO THE SOUTH AND EAST. SOME VSBY AND CIG RESTRICTIONS TO MVFR WILL BE POSSIBLE IN AND AROUND THE THUNDERSTORMS BUT OVERALL IT SHOULD BE VFR DUE TO DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE. CONDITIONS WILL THEN IMPROVE FROM NW TO SE AS THE DAY WEARS ON AND INTO THE EVENING WITH SKIES CLEARING AND GUSTY WINDS DEVELOPING FOR A TIME. && .PRELIMINARY POINT TEMPS/POPS... DLH 44 67 40 68 / 0 0 0 0 INL 38 66 38 74 / 0 0 0 0 BRD 44 70 41 70 / 0 0 0 10 HYR 44 70 40 69 / 20 0 0 10 ASX 44 67 37 69 / 10 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...DAP SHORT TERM...GSF LONG TERM...LE AVIATION...GRANING
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
122 PM CDT Sun May 3 2015 .UPDATE: Issued at 104 PM CDT Sun May 3 2015 Nudged temps up a degree or two from the metro area east. Lowered Dps across s cntrl IL which match observed RH values already below 30%. The low RHs and fuel moisture below 10 percent will combine with breezy conditions to create elevated fire conditions this afternoon across s cntrl IL. Reduced going sky cover to clear/mostly. Also reduced PoPs this aftn across NE MO and w cntrl IL as it doesn`t appear that this threat will materialize. 2% && .SHORT TERM: (Today and Tonight) Issued at 325 AM CDT Sun May 3 2015 There is quite a bit of cloud cover early this morning across the region courtesy of two weak short waves in the westerly flow aloft. The first of these currently centered from northern IL into southeast MO has been generating some spotty high-based showers from the associated mid clouds/moisture. Present indications are this wave and the mid level moisture will continue to push east this morning with a few sprinkles still possible after 12z in south central IL. The other short wave is currently centered near the Nebraska/Iowa border into northeast KS and is more problematic. The associated convection has generated a sizable cloud canopy which has not been resolved by the models and will overspread a good portion of the CWA this morning. Unclear is how it will evolve with time - i.e. thinning, but the RAP has this wave centered through far eastern IA at midday and the current thought is to have quite a bit of clouds the first half of this morning then thinning and moving east by midday into early afternoon. There are also suggestions in the RAP, ECMWF, and a few of the hi-res WRFs that the southwest stretching tail of this short wave could generate a few showers across northeast MO and west central IL this afternoon and early this evening. I have added a slight chance as a result. Otherwise a warm day is on tap with well above normal temperatures expected. While the morning clouds will hamper the temp rise a bit, increasing south-southwesterly low level flow and rising low- level temperatures should compensate and will result in highs in the upper 70s to mid 80s across the area. South-southwest lower trop flow will maintain a low-level warm advection region tonight and moisture will gradually be improving. The thermal and moisture advection combined with a plume of relatively steep mid level lapse rates will result in a swath of weak instability across northern parts of the CWA in advance of the southward sinking cold front. While the front will remain well north of the CWA at daybreak Monday, northwest steering flow will help push at least scattered showers and thunderstorms or thunderstorm clusters into northeast MO and west central IL late tonight. We could also see spotty WAA generated showers well in advance of the activity that has moved off the front, hence the low pops all the way down to St. Louis. Glass .LONG TERM: (Monday through Saturday) Issued at 325 AM CDT Sun May 3 2015 The west-east oriented cold front will ooze southward out of IA and northern IL into northern sections of the CWA by early Monday evening. Ongoing showers and thunderstorms at daybreak should dissipate by midday. Heating and continued low-level moistening in their wake will result in weak-moderate instability along the frontal zone and the combo of a migrating impulse and good low level convergence along the boundary should result in extensive convective development during the later half of the afternoon spanning from KS across northern MO/southern IA into central IL. A broad veering southwesterly LLJ will maintain numerous thunderstorms/clusters during the evening, with the activity shunting a bit northward overnight in response to increasing ridging aloft and a slight northward shift in the frontal zone. The front will continue to shift northward on Tuesday as ridging aloft continues to build from the lower TN Valley into the upper MS Valley. There are some suggestions of air mass type convection across southern portions of the CWA but I`m not sold on it and have kept pops in the slight range and confined the coverage. Otherwise Tuesday will be another day of above normal temps with highs in the 80s. This warmth will persist on Wednesday and even into Thursday with the chance of showers and thunderstorms slowly increasing west-east over the 2 day period as the ridging aloft shunts east and southwest flow aloft becomes more dominant with time. The greatest threat of showers and thunderstorms in the extended period will be Friday-Saturday with an active southwest flow aloft, moist unstable warm sector, and slowly encroaching cold front. Glass && .AVIATION: (For the 18z TAFs through 18z Monday Afternoon) Issued at 104 PM CDT Sun May 3 2015 VFR fcst thru the prd. The region is on the backside of a large sfc ridge that is fcst to remain anchored just off the east coast. This will keep the area in return flow for an extended prd. Guidance indicates that a cold front will approach the region tonight but should stall along or near the IA/MO border. This will limit the best precip chances to those areas and have included a VCSH group at KUIN late tonight to account for the threat...though not confident that precip will make it that far south. Can`t completely rule out precip further south tonight into Monday mrng near I70 as these types of patterns often produce isld light precip further east and south than expected. Specifics for KSTL: Dry VFR fcst with sthrly flow...diurnal cu and aftn gusts. 2% && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
700 AM CDT Sun May 3 2015 .SHORT TERM: (Today and Tonight) Issued at 325 AM CDT Sun May 3 2015 There is quite a bit of cloud cover early this morning across the region courtesy of two weak short waves in the westerly flow aloft. The first of these currently centered from northern IL into southeast MO has been generating some spotty high-based showers from the associated mid clouds/moisture. Present indications are this wave and the mid level moisture will continue to push east this morning with a few sprinkles still possible after 12z in south central IL. The other short wave is currently centered near the Nebraska/Iowa border into northeast KS and is more problematic. The associated convection has generated a sizeable cloud canopy which has not been resolved by the models and will overspread a good portion of the CWA this morning. Unclear is how it will evolve with time - i.e. thinning, but the RAP has this wave centered through far eastern IA at midday and the current thought is to have quite a bit of clouds the first half of this morning then thinning and moving east by midday into early afternoon. There are also suggestions in the RAP, ECMWF, and a few of the hi-res WRFs that the southwest stretching tail of this short wave could generate a few showers across northeast MO and west central IL this afternoon and early this evening. I have added a slight chance as a result. Otherwise a warm day is on tap with well above normal temperatures expected. While the morning clouds will hamper the temp rise a bit, increasing south-southwesterly low level flow and rising low- level temperatures should compensate and will result in highs in the upper 70s to mid 80s across the area. South-southwest lower trop flow will maintain a low-level warm advection region tonight and moisture will gradually be improving. The thermal and moisture advection combined with a plume of relatively steep mid level lapse rates will result in a swath of weak instability across northern parts of the CWA in advance of the southward sinking cold front. While the front will remain well north of the CWA at daybreak Monday, northwest steering flow will help push at least scattered showers and thunderstorms or thunderstorm clusters into northeast MO and west central IL late tonight. We could also see spotty WAA generated showers well in advance of the activity that has moved off the front, hence the low pops all the way down to St. Louis. Glass .LONG TERM: (Monday through Saturday) Issued at 325 AM CDT Sun May 3 2015 The west-east oriented cold front will ooze southward out of IA and northern IL into northern sections of the CWA by early Monday evening. Ongoing showers and thunderstorms at daybreak should dissipate by midday. Heating and continued low-level moistening in their wake will result in weak-moderate instability along the frontal zone and the combo of a migrating impulse and good low level convergence along the boundary should result in extensive convective development during the later half of the afternoon spanning from KS across northern MO/southern IA into central IL. A broad veering southwesterly LLJ will maintain numberous thunderstorms/clusters during the evening, with the activity shunting a bit northward overnight in response to increasing ridging aloft and a slight northward shift in the frontal zone. The front will continue to shift northward on Tuesday as ridging aloft continues to build from the lower TN Valley into the upper MS Valley. There are some suggestions of air mass type convection across southern portions of the CWA but I`m not sold on it and have kept pops in the slight range and confined the coverage. Otherwise Tuesday will be another day of above normal temps with highs in the 80s. This warmth will persist on Wednesday and even into Thursday with the chance of showers and thunderstorms slowly increasing west-east over the 2 day period as the ridging aloft shunts east and southwest flow aloft becomes more dominant with time. The greatest threat of showers and thunderstorms in the extended period will be Friday-Saturday with an active southwest flow aloft, moist unstable warm sector, and slowly encroaching cold front. Glass && .AVIATION: (For the 12z TAFs through 12z Monday Morning) Issued at 700 AM CDT Sun May 3 2015 VFR conditions to prevail through forecast period with just mid and high clouds. Low level wind shear to diminish by mid morning with winds mixing down to surface. Winds to pickup from the south to southwest and gust to around 20kts at times this afternoon before diminishing towards sunset. Some showers possible around KUIN but will be widely scattered so no mention for now. As for next system that will approach late tonight, did add vicinity shower mention at KUIN, dry elsewhere. Specifics for KSTL: VFR conditions to prevail through forecast period with just mid and high clouds. Low level wind shear to diminish by 14z Sunday with winds mixing down to surface. Winds to pickup from the south and gust to around 20kts at times this afternoon before diminishing after 01z Monday. As for next system that will approach late tonight, activity to remain north of metro area. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
341 AM CDT Sun May 3 2015 .SHORT TERM: (Today and Tonight) Issued at 325 AM CDT Sun May 3 2015 There is quite a bit of cloud cover early this morning across the region courtesy of two weak short waves in the westerly flow aloft. The first of these currently centered from northern IL into southeast MO has been generating some spotty high-based showers from the associated mid clouds/moisture. Present indications are this wave and the mid level moisture will continue to push east this morning with a few sprinkles still possible after 12z in south central IL. The other short wave is currently centered near the Nebraska/Iowa border into northeast KS and is more problematic. The associated convection has generated a sizeable cloud canopy which has not been resolved by the models and will overspread a good portion of the CWA this morning. Unclear is how it will evolve with time - i.e. thinning, but the RAP has this wave centered through far eastern IA at midday and the current thought is to have quite a bit of clouds the first half of this morning then thinning and moving east by midday into early afternoon. There are also suggestions in the RAP, ECMWF, and a few of the hi-res WRFs that the southwest stretching tail of this short wave could generate a few showers across northeast MO and west central IL this afternoon and early this evening. I have added a slight chance as a result. Otherwise a warm day is on tap with well above normal temperatures expected. While the morning clouds will hamper the temp rise a bit, increasing south-southwesterly low level flow and rising low- level temperatures should compensate and will result in highs in the upper 70s to mid 80s across the area. South-southwest lower trop flow will maintain a low-level warm advection region tonight and moisture will gradually be improving. The thermal and moisture advection combined with a plume of relatively steep mid level lapse rates will result in a swath of weak instability across northern parts of the CWA in advance of the southward sinking cold front. While the front will remain well north of the CWA at daybreak Monday, northwest steering flow will help push at least scattered showers and thunderstorms or thunderstorm clusters into northeast MO and west central IL late tonight. We could also see spotty WAA generated showers well in advance of the activity that has moved off the front, hence the low pops all the way down to St. Louis. Glass .LONG TERM: (Monday through Saturday) Issued at 325 AM CDT Sun May 3 2015 The west-east oriented cold front will ooze southward out of IA and northern IL into northern sections of the CWA by early Monday evening. Ongoing showers and thunderstorms at daybreak should dissipate by midday. Heating and continued low-level moistening in their wake will result in weak-moderate instability along the frontal zone and the combo of a migrating impulse and good low level convergence along the boundary should result in extensive convective development during the later half of the afternoon spanning from KS across northern MO/southern IA into central IL. A broad veering southwesterly LLJ will maintain numberous thunderstorms/clusters during the evening, with the activity shunting a bit northward overnight in response to increasing ridging aloft and a slight northward shift in the frontal zone. The front will continue to shift northward on Tuesday as ridging aloft continues to build from the lower TN Valley into the upper MS Valley. There are some suggestions of air mass type convection across southern portions of the CWA but I`m not sold on it and have kept pops in the slight range and confined the coverage. Otherwise Tuesday will be another day of above normal temps with highs in the 80s. This warmth will persist on Wednesday and even into Thursday with the chance of showers and thunderstorms slowly increasing west-east over the 2 day period as the ridging aloft shunts east and southwest flow aloft becomes more dominant with time. The greatest threat of showers and thunderstorms in the extended period will be Friday-Saturday with an active southwest flow aloft, moist unstable warm sector, and slowly encroaching cold front. Glass && .AVIATION: (For the 06z TAFs through 06z Sunday Night) Issued at 1128 PM CDT Sat May 2 2015 VFR flight conditions are expected to continue through Sunday. Very light showers continue to drift southeast over parts of the area. Shower activity should continue to diminish slowly through the rest of the night. Showers are so light that there should be no impact to operations if one does move over an airport. Low level wind shear is a good possibility especially over central and northeast Missouri as well as west central Illinois. Models are indicating that the wind will increase to around 30kts between 400-800 ft providing +/- 20-25 kts of shear from the surface to those altitudes. Shear values look to fall off further east/southeast. Expect increasing south-southwest wind on Sunday morning with gusts to around 20kts during the afternoon. Specifics for KSTL: VFR flight conditions are expected to continue through Sunday. There may be a sprinkle or two through the rest of the night, but airport operations are not expected to be affected. Some low level wind shear still looks possible at Lambert, but values do not look high enough to warrant a mention in the TAF at this time. Wind will increase from the south-southwest Sunday morning with gusts to around 20kts during the afternoon. Carney && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
905 AM MDT SUN MAY 3 2015 .UPDATE... WEAK ECHOES ON RADAR FROM S OF KBIL THROUGH SE MT THIS MORNING WERE MAINLY MID CLOUDS PER SURFACE OBSERVATIONS...WITH POSSIBLE SPRINKLES. WEB CAMS SHOWED DRY CONDITIONS. SPRINKLES/MID CLOUDS WERE BEING INDUCED BY WEAK RIGHT-REAR JET QUADRANT UPPER DIVERGENCE WHICH WILL CONTINUE THROUGH THE EVENING FROM THE 90 KT JET TO THE N OF THE AREA. NEW WRF SHOWED MID-LEVEL FRONTOGENESIS OVER THE AREA OF RADAR ECHOES INTO THE AFTERNOON. CHANCE OF SPRINKLES WILL END BY 18Z AS FRONTOGENESIS MOVES OUT. ISENTROPIC LIFT INCREASES OVER WESTERN AREAS BY 00Z TONIGHT. TRIMMED BACK THE SPRINKLES TO BETTER FIT THE CURRENT RADAR ECHOES AND REMOVED POPS FROM THE NE BIGHORNS THIS MORNING. THE AFTERNOON POPS OVER THE MOUNTAINS WERE FINE AND NO MENTION OF THUNDER MADE SENSE GIVEN THE LOW CAPES ON THE SREF...AND RAP SOUNDINGS. TEMPERATURES AND DEWPOINTS LOOKED GOOD TODAY. ADJUSTED SKY COVER BASED ON CURRENT SATELLITE...AND WIND SPEEDS BASED ON LATEST GUIDANCE. KLVM TENDS TO BECOME GUSTY WITH AN E WIND. LOW-LEVEL SE FLOW INCREASES TONIGHT AND MON WHILE ISENTROPIC LIFT CONTINUES OVER THE AREA. POPS WERE IN GOOD SHAPE. ARTHUR && .SHORT TERM...VALID FOR TDY AND MON... QUIET END TO THE WEEKEND EXPECTED AS A WESTERLY FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA TODAY. SATELLITE SHOWING AN AREA OF CLOUDS ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE STATE WITH CLEARING JUST TO THE WEST OF OUR AREA. EXPECT THESE CLOUDS TO MOVE EAST ALLOWING FOR PARTLY SUNNY SKIES TO DEVELOP FROM WEST TO EAST TODAY. RADAR HAS BEEN SHOWING SOME RETURNS FROM ABOUT BIG HORN COUNTY EAST TO THE DAKOTAS. HOWEVER...BELIEVE MOST IF NOT ALL OF THIS IS VIRGA AS TEMPERATURE/DEWPOINT SPREADS ARE QUITE HIGH AND CLOUD BASES ARE AROUND 11K FEET. TEMPERATURES TODAY WILL BE A GOOD 10 DEGREES COOLER AS A RESULT OF THE FRONT THAT MOVED THROUGH LAST EVENING. MOST AREAS WILL SEE HIGHS IN THE 60S WHICH IS NORMAL FOR THIS TIME OF YEAR. AN UPPER LOW AND TROUGH APPROACH THE PACIFIC NORTHWEST COAST LATE IN THE DAY MONDAY. THIS WILL ALLOW THE FLOW TO BUCKLE SOMEWHAT RESULTING IN WEAK RIDGING BUILDING ACROSS OUR AREA...AS WELL AS A SOUTHWEST FLOW ALOFT. A WEAK DISTURBANCE WILL MOVE NORTHEAST OUT OF THE GREAT BASIN AREA DURING THE AFTERNOON AND EVENING BRINGING A SLIGHT SHOWER AND ISOLATED THUNDERSTORM CHANCE TO OUR FAR WESTERN AREAS WITH THE BEST CHANCES OVER THE ABSAROKA/BEARTOOTH AND BIG HORN MOUNTAINS AND ADJACENT FOOTHILLS. AS THE DISTURBANCE MOVES EAST...THE BETTER SHOWER CHANCES WILL SHIFT ACROSS OUR SOUTHEAST COUNTIES MONDAY NIGHT. TEMPERATURES MONDAY WILL WARM BACK TO ABOVE NORMAL WITH READINGS IN THE 70S...EXCEPT FOR SOME 60S OUT TOWARD THE DAKOTA BORDERS. HOOLEY .LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT... MODELS HAVE CONTINUED THE SAME GENERAL PATTERN IN THE LONG TERM...WETTER AND COOLER. TUESDAY THE LOW OVER THE PACIFIC WILL BEGIN TO MOVE ALONG THE COAST AS IT DIGS SOUTH. THIS WILL BRING MOIST SOUTHWEST FLOW INTO THE AREA. THE FLOW WILL GENERALLY BE UNSETTLED AS SEVERAL IMPULSES OF ENERGY MOVE THROUGH THE FLOW. THIS WILL GIVE THE AREA A SHOT AT RAIN...BUT MOSTLY IN THE MOUNTAINS. THE BEST CHANCES FOR RAIN WILL COME TOWARDS THE WEEKEND AS THE LOW IN THE GREAT BASIN LIFTS INTO WYOMING. THIS WILL BRING THE GREATEST ENERGY MOVING THROUGH COINCIDENT WITH SOME DECENT FORCING. THERE CONTINUES TO BE SOME TIMING AND PLACEMENT ISSUES BETWEEN THE MODELS WITH THE PRECIP...SO HAVE NOT GOTTEN TOO SPECIFIC. WITH THE INCREASED MOISTURE AND CLOUDINESS...CONTINUE TO EXPECT TEMPERATURES TO BE NEAR NORMAL...GENERALLY IN THE 60S FOR HIGHS. REIMER && .AVIATION... VFR CONDITIONS WILL CONTINUE TO PREVAIL OVER THE NEXT 24 HOURS. WINDS WILL GENERALLY BE LIGHT THROUGHOUT THE DAY. SOME SHOWERS WILL CONTINUE TO BE POSSIBLE IN THE MOUNTAINS WITH LOCALIZED MOUNTAIN OBSCURATION. REIMER/FRIEDERS && .PRELIMINARY POINT TEMP/POPS... TDY MON TUE WED THU FRI SAT ------------------------------------------------------- BIL 065 045/075 050/076 047/065 045/051 040/053 041/058 1/B 11/B 12/T 54/T 34/W 44/W 55/W LVM 066 038/074 043/075 041/062 039/047 035/049 036/059 2/W 12/T 23/T 55/T 45/W 44/W 55/W HDN 067 043/078 045/079 046/067 044/054 040/056 040/062 1/B 21/B 12/T 43/T 34/W 33/W 44/W MLS 066 045/073 049/076 050/067 044/059 041/060 042/060 0/B 11/N 11/B 44/T 33/W 33/W 34/W 4BQ 066 043/070 046/074 048/066 045/059 042/056 040/060 1/B 32/W 11/N 45/T 33/W 33/W 44/W BHK 064 039/067 045/070 047/064 043/058 038/057 038/056 1/B 12/W 11/N 46/T 33/W 22/W 34/W SHR 065 043/072 044/072 044/063 041/054 038/055 039/057 2/W 32/T 22/T 44/T 34/W 44/W 55/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
635 PM CDT MON MAY 4 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM CDT MON MAY 4 2015 A WEAK DISTURBANCE AND MID-LEVEL WARM FRONT WILL PROVIDE FOR ADDITIONAL SHOWERS AND THUNDERSTORMS THIS EVENING AND OVERNIGHT. THE 04.12Z NAM SEEMS TO BE HANDLING THE CURRENT SITUATION WELL...AND THUS WAS CONSIDERED FOR THE POP FORECAST OVERNIGHT. AT THIS POINT...BESIDES OFF AND ON SCATTERED SHOWERS...THE GREATEST CHANCES OF POPS OVERNIGHT COME DURING THE PRE-DAWN HOURS ACROSS OUR SOUTHERN ZONES...THEN THE ACTIVITY LIFTS NORTH THROUGH 15Z. AT THIS POINT WILL GENERALLY KEEP CHANCES AT 50% OR LESS OVERNIGHT. ONLY A WEAK CONVECTIVE ELEMENT IS SHOWN IN REGIONAL PROXIMITY SOUNDINGS OVERNIGHT...SO AT MOST A FEW CG STRIKES WOULD BE ANTICIPATED. A WARM FRONT WILL LIFT NORTH EARLY TUESDAY...PROVIDING A FOCUS FOR ADDITIONAL SHOWERS AND STORMS. MODELS REMAIN IN DECENT AGREEMENT WITH TIMING SUGGESTING THE ARRIVAL EARLY TUESDAY AFTERNOON AS DIFLUENCE ALOFT INCREASES WITH THE APPROACH OF A LEAD CENTRAL ROCKIES SHORTWAVE. THE MODELS INDICATE SUFFICIENT DESTABILIZATION FOR THUNDERSTORM DEVELOPMENT...BUT BULK SHEAR INDICES ARE LESS THAN OPTIMAL FOR ORGANIZED STORM ROTATION. THUS WIDESPREAD SEVERE STORMS ARE NOT ANTICIPATED...BUT A FEW STRONG STORMS TUESDAY AFTERNOON CANNOT BE OVERLOOKED. THE CONTRIBUTION OF THE INSTABILITY IS SPREAD OVER A LARGE DISTANCE OF THE TROPOSPHERE AND GIVEN THAT PWATS ARE SHOWN TO INCREASE TO VALUES OF ABOVE THE 99TH PERCENTILE...HEAVY RAINFALL IS ANTICIPATED UNDER ANY CONVECTIVE STORM. THE GREATEST THREAT OF HEAVY RAINFALL WILL OCCUR BEYOND 21Z TUESDAY AFTERNOON WHEN WARM CLOUD DEPTHS INCREASE ABOVE 6K FEET. THE INHERITED FORECAST INCLUDED LIKELY POPS TUESDAY AFTERNOON...WHICH AT THIS POINT THERE/S NO REASON TO DEVIATE GIVEN THE SITUATION. TEMPERATURES WILL BE MODERATED BY THE PRESENCE OF CLOUDS AND MOISTURE...LOWS WILL FALL INTO THE 40S TO LOWER 50S OVERNIGHT...WITH HIGHS WARMING INTO THE 60S TO LOWER 70S TOMORROW...ESPECIALLY IF THE SUN IS ABLE TO PEEK OUT. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 353 PM CDT MON MAY 4 2015 A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL BE DIGGING SOUTHEAST TOWARD THE CENTRAL GREAT BASIN BY FRIDAY. IN ADVANCE OF THIS SYSTEM...A POTENT NEGATIVELY TILTED PV ANOMALY WILL EJECT NORTHEAST FROM THE DESERT SOUTHWEST ACROSS THE AREA TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. THIS LEAD PV ANOMALY WILL HELP TO INCREASE SOUTHERLY FLOW...WITH ABUNDANT LOW LEVEL GULF MOISTURE STREAMING NORTHWARD INTO THE CENTRAL AND NORTHERN PLAINS. THE RAIN EXPECTED DURING THE DAY TUESDAY WILL DECREASE SOMEWHAT IN COVERAGE TUESDAY NIGHT AS THE BEST LIFT SHIFTS NORTH INTO THE NORTHERN PLAINS. STILL CANNOT RULE OUT SHOWERS OR A FEW STORMS WITH GOOD MOISTURE ADVECTION AND SOME LIFT PRESENT THROUGH THE NIGHT. THE BEST DYNAMICS ASSOCIATED WITH THE PV ANOMALY WILL CROSS THE AREA WEDNESDAY. STILL NOT EXPECTING MUCH IN THE WAY OF DESTABILIZATION DURING THE AFTERNOON AHEAD OF THE COLD FRONT DUE TO ABUNDANT LOW LEVEL MOISTURE AND LOW STRATUS CLOUD COVER. THE RESULT WOULD BE LIMITED SURFACE BASED CONVECTIVE DEVELOPMENT. THE MORE LIKELY SCENARIO WILL BE FOR SURFACE BASED STORMS TO DEVELOP NEAR A TRIPLE POINT ACROSS NORTHWEST KANSAS WHERE LESS LOW CLOUD COVER AND BETTER HEATING WILL OCCUR. EXPECT THESE STORMS TO QUICKLY SPREAD NORTH AND EAST AND BECOME MORE ELEVATED. A FEW OF THESE COULD BE SEVERE WITH LARGE HAIL BEING THE MAIN THREAT. STILL ON TRACK FOR A LULL IN THE PRECIPITATION LATER WEDNESDAY NIGHT INTO THURSDAY. THEN FRIDAY INTO THE WEEKEND...THE LARGE UPPER LEVEL LOW WILL MOVE EAST FROM THE CENTRAL GREAT BASIN TOWARD THE CENTRAL PLAINS. ECMWF AND GEFS CONTINUE TO BE IN VERY GOOD AGREEMENT WITH THE CLOSED LOW TRACKING SLOWLY ACROSS COLORADO AND THEN TURN NORTHEAST AND CROSS NEBRASKA. VERY STRONG MOISTURE ADVECTION AHEAD OF THIS SYSTEM...AND HIGH CONFIDENCE THAT RAIN WILL OCCUR FRIDAY NIGHT INTO SATURDAY. THE GEFS AND ECMWF NOW LINGER THE SYSTEM INTO SUNDAY...SO WILL RAISE POPS FOR THAT DAY. MONDAY SHOULD BE A DRY DAY AS THE SYSTEM MOVES NORTHEAST AWAY FROM THE REGION. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 635 PM CDT MON MAY 4 2015 MVFR CIGS ASSOCIATED WITH RAIN ALONG I-80 WILL CONTINUE FOR A FEW MORE HOURS. ONCE THE RAIN ENDS...A PERIOD OF VFR COULD DEVELOP FOR A FEW HOURS ALSO. THE RAP MODEL THEN SHOWS A RAPID INCREASE IN MOISTURE WHICH IS EXPECTED TO LOWER CIGS AGAIN TO MVFR WITH AREAS OF IFR TOWARD MORNING AS A SECOND BATCH OF RAIN MOVES UP FROM THE SOUTH. THE MODELS SUGGEST THIS RAIN COULD LAST THROUGHOUT THE DAY SOUTH OF VALENTINE. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JACOBS LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1259 PM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 924 AM CDT SUN MAY 3 2015 JUST UPDATED TO ADD A 2-3 HOUR WINDOW OF OPPORTUNITY FOR ISOLATED RAIN SHOWERS/WEAK THUNDERSTORMS TO SEVERAL COUNTIES MAINLY EAST OF AN OSBORNE-CLAY CENTER-OSCEOLA LINE THIS MORNING. ALTHOUGH FORCING IS SUBTLE...THIS RECENT UPTICK IN ELEVATED ACTIVITY APPEARS TO BE TIED TO A SUBTLE MID LEVEL PASSING THROUGH AND GENERATING "JUST ENOUGH" LOW-MID LEVEL THETA-E ADVECTION TO KICK THINGS OFF. ALTHOUGH MODELS HAVE STRUGGLED TO PICK UP ON THIS...WOULD BE SURPRISED TO SEE ANY OF THIS EASTERN ACTIVITY LINGER PAST THE 11AM-12PM HOUR...AS STILL EXPECT THE MAJORITY OF THE CWA TO REMAIN DRY THE MAJORITY OF THE DAY. AS FOR THE LATE AFTERNOON/EVENING/OVERNIGHT STORM CHANCES...UNFORTUNATELY...UNCERTAINTY MAY BE HIGHER IN THE NOW THAN IT WAS 24 HOURS AGO REGARDING HOW THIS PLAYS OUT. PER SOME MODELS...THE OVERALL SEVERE THREAT MAY BE A BIT LESS THAN THOUGHT 24 HOURS AGO...BUT THAT BEING SAID...GIVEN WHAT HAPPENED YESTERDAY WITH THE GREATER-THAN-EXPECTED COVERAGE OF STRONG- SEVERE STORMS IN THE NORTHEAST CWA...THIS PATTERN IS PRONE TO YIELDING SURPRISES. STAY TUNED FOR PLENTY MORE THOUGHTS/UPDATED THINKING WITH THE AFTERNOON DISCUSSION. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 433 AM CDT SUN MAY 3 2015 BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SPLIT FLOW FOR TODAY...CAUGHT BETWEEN THE NORTH AND SOUTH STREAMS. LOCAL SYNOPTIC FLOW WILL BE ZONAL...BUT TURN MORE SOUTHWEST TONIGHT AS A NEGATIVELY TILTED BROAD UPPER LEVEL TROUGH ENTERS THE SOUTHWESTERN UNITED STATES. AT THE SURFACE...A COLD FRONT IS ON ITS WAY SOUTH ACROSS SOUTH DAKOTA. THE TIMING OF THIS FRONT SUGGESTS THAT WE WILL WARM UP SIGNIFICANTLY DUE TO COMPRESSIONAL WARMING. MODELS ARE GENERALLY NOT PICKING UP ON THIS WELL ENOUGH...SO I AM GOING OUT ON A BIT OF A LIMB AND GOING QUITE A BIT MORE THAN GENERAL GUIDANCE IN THE MID 80S. GOING FOR 91 FOR THE TRI-CITIES...FAVORING THE HI RES NMM SOLUTION. BELIEVE IT OR NOT...THIS WOULD BREAK OUR RECORD IN HASTINGS BY 2 DEGREES AND BE ONE DEGREE SHORT OF THE RECORD HIGH IN GRAND ISLAND. THE RAP MODEL BUMPS UP TEMPERATURES EVEN MORE IN NORTH CENTRAL KANSAS TO THE MID 90S. THESE WARMER TEMPERATURES WOULD HAVE PUT US IN THE REALM OF APPROACHING CRITICAL FIRE WEATHER ISSUES IF IT WERE NOT FOR THE FACT THAT WE HAVE GREENED UP. CHANCES OF PRECIPITATION ARE NOT CERTAIN. COVERAGE IS A BIT SPOTTY UNTIL THE CAP BREAKS IN THE EVENING. EVENT THEN...COVERAGE IS IN QUESTION...ESPECIALLY DEPENDING ON THE EXACT PLACEMENT OF THE FRONT WHEN STORMS FIRE. WE WILL PROBABLY NEED A HIGHER NARROW CORRIDOR OF CATEGORICAL CHANCES OF SHOWERS/THUNDERSTORMS...BUT AT THIS TIME...THAT IS VERY DIFFICULT TO DETERMINE...ESPECIALLY AS THE FRONT MAY TEMPORARILY STALL FOR A SHORT TIME TOWARD EVENING. A SECONDARY IMPULSE WITHIN MID-LEVEL FLOW COULD BOOST CHANCES OF RAIN OVERNIGHT...PROBABLY IN OUR SOUTH. I DO NOT GO OVER A 60 PERCENT CHANCE ANYWHERE IN THE CWA...AND HANG AROUND 40-50 PERCENT CHANCE FOR THE TRI-CITIES. AS FOR STRONG/SEVERE CHANCES...WE COULD GET SOME STRONG STORMS WITH MARGINAL INSTABILITY OF 500 TO 1500 J/KG AND LOW- LEVEL WIND SHEAR APPROACHING 30-35 IN OUR NORTH...BUT PROBABLY LOWER IN MOST OF THE REST OF THE CWA. THIS COULD BE ENOUGH TO GIVE US SOME STRONG STORMS WITH NICKEL SIZE HAIL AND PERHAPS A STRONG WIND GUST...BUT THE BETTER SUPPORT FOR SEVERE WEATHER LOOKS LIKE IT SHOULD BE EAST/NORTHEAST OF THE CWA. WENT WITH SIMILAR LOWS FOR TONIGHT COMPARED TO THE PREVIOUS FORECAST AND STUCK WITH SUPERBLEND IN THE 50S. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 433 AM CDT SUN MAY 3 2015 PRIMARY FORECAST CONCERN CONTINUES TO REVOLVE AROUND THE MULTIPLE CHANCES FOR THUNDERSTORMS THROUGH THE ENTIRE PERIOD. THE UNSETTLED WEATHER PATTERN HAS SETTLED IN ACROSS THE REGION BY THE START OF THE PERIOD MON/MON NIGHT...WITH MODELS SHOWING THE AREA UNDER SOUTHWESTERLY FLOW ALOFT...WITH THE PARENT LOW PRESSURE OVER SRN CALIFORNIA AND WEAK RIDGING EXTENDING NORTH FROM THE GULF COAST INTO PORTIONS OF THE MIDWEST. MAY HAVE SOME LINGERING PRECIP ACROSS THE AREA DURING THE MORNING HOURS FROM OVERNIGHT ACTIVITY...BUT WOULD THINK THERE WOULD BE A LULL AT SOME POINT. HARD TO PINPOINT EXACTLY WHERE THAT LINGERING ACTIVITY MAY BE...SO HAVE CHANCE POPS ACROSS THE ENTIRE CWA. AT THE SFC...MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT SHOWING THE PLACEMENT OF THE MAIN SFC FRONT OVER SRN PORTIONS OF THE CWA NEAR THE NEB/KS STATE LINE...WITH SOME SHOWING A LOW PLACED IN CLOSE PROXIMITY TO THE S/SWRN CORNER OF THE CWA. THE PLACEMENT OF THE SFC FRONT...UNCERTAINTY WITH THE AMOUNT OF SKY COVER /LIKELY HIGH/ AND ANY LINGERING PRECIP MAKES THE HIGH TEMP FORECAST TRICKY. MUCH OF SC NEB IS LOOKING AT ERLY WINDS NORTH OF THE FRONT...WITH MORE SRLY WINDS ACROSS NC KS. FORECAST HIGH TEMP IS A BLEND...AND COULD SEE CLOSE TO A 20 DEGREE GRADIENT ACROSS THE CWA /SOME MODELS ARE MORE DRASTIC/...WITH ARND 60 IN THE NORTH TO NEAR 80 IN THE FAR SOUTH. DURING THE AFTERNOON HOURS AND INTO THE EVENING/OVERNIGHT...THIS FRONTAL BOUNDARY WILL BE A FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT AS YET ANOTHER DISTURBANCE MAKES ITS WAY INTO THE REGION...AIDED ALSO BY AN INCREASING LLJ. SEVERE WEATHER REMAINS A CONCERN WITH MODEST INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR...LARGE HAIL/DAMAGING WINDS REMAIN THE PRIMARY CONCERNS...BUT WILL HAVE TO MONITOR THE POTENTIAL FOR AN ISOLATED TORNADO WITH THOSE MORE ERLY WINDS/INCREASED LOW LEVEL SHEAR IN THE AREA. SPC DAY 2 OUTLOOK SLIGHT RISK AREA INCLUDES ROUGHLY THE SERN HALF OF THE CWA. SIMILAR TO MONDAY...TUESDAY MORNING MAY HAVE SOME LINGERING ACTIVITY FROM OVERNIGHT...BUT MODELS SUGGEST THE OVERALL COVERAGE MAY NOT BE AS WIDESPREAD. THE MAIN UPPER LEVEL LOW HAS SHIFTED EAST INTO THE FOUR CORNERS REGION BY TUESDAY MORNING...AND MODELS CONTINUE TO SHOW THE POTENTIAL FOR THE LOW TO WEAKEN SOME/FILL...AS IT COMES UNDER INCREASING INFLUENCE OF A STRONGER UPPER LEVEL LOW MOVING INTO THE PAC NW REGION. AT THE SFC...DURING THE DAYTIME HOURS...THE FRONTAL BOUNDARY CONTINUING TO MEANDER AROUND CENTRAL PORTIONS OF THE CWA LOOKS TO PUSH NORTH AS A WARM FRONT...WITH MOST MODELS SHOWING SRLY WINDS IN PLACE ACROSS THE ENTIRE CWA DURING THE AFTERNOON. MODELS CONTINUE TO SHOW THE BETTER THUNDERSTORMS CHANCES ACROSS WRN PORTIONS OF THE CWA DURING THE AFTERNOON...SPREADING ACROSS THE REST OF THE CWA OVERNIGHT AS LIFT CONTINUES TO INCREASE WITH THE APPROACHING MAIN UPPER TROUGH/LOW...WHICH IS STARTING TO MAKE MORE OF A PUSH ONTO THE THE PLAINS DURING THE LATE TUES NIGHT HOURS/WED MORNING. WED/WED NIGHT CONTINUES TO BE THE PERIOD GENERALLY SHOWN BY MODELS WHEN THAT MAIN TROUGH AXIS /CLOSED LOW?/ MAKES ITS TREK NE THROUGH THE REGION...AS THAT STRONGER UPPER LEVEL LOW DIGS FURTHER SOUTH ALONG THE WEST COAST. THE HIGH CHANCE/LOW END LIKELY POPS CONTINUE IN THE FORECAST...SIMILAR TO PERIODS PRIOR AND FOLLOWING...HARD TO TRIM AREAS OUT OR RAISE POPS IN OTHERS WHEN SO MANY DETAILS HAVE YET TO BE IRONED OUT. THE LOCATION OF THE SFC LOW/ASSOCIATED BOUNDARIES LOOK TO BE PLAYING A BIGGER ROLE/FOCUS FOR CONVECTIVE DEVELOPMENT NEAR/ACROSS THE CWA...SO AS THEIR ULTIMATE PLACEMENT BECOMES MORE CLEAR IN THE COMING MODEL RUNS...CAN PIN DOWN BETTER DETAILS WITH POPS AND SEVERE WEATHER POTENTIAL. THROUGH THE REST OF THE LONG TERM PERIOD THURSDAY THROUGH SATURDAY...ONE NOTABLE DISTURBANCE MOVES OUT...BUT SOUTHWESTERLY FLOW REMAINS IN PLACE IN THE UPPER LEVEL AS THAT NEXT LOW PRESSURE SYSTEM CONTINUES TO DIG FURTHER SOUTH INTO CALIFORNIA. PIECES OF SHORTWAVE ENERGY ASSOCIATED WITH THAT LOW LOOK TO CONTINUE TO BRING AT LEAST PERIODIC THUNDERSTORM CHANCES...KEPT THE FORECAST CLOSE TO THE CR INIT/SUPERBLEND OUTPUT. && .AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1247 PM CDT SUN MAY 3 2015 ALTHOUGH CONFIDENCE IS REASONABLY HIGH IN WIND TRENDS...INCLUDING THE PASSAGE OF A FAIRLY NOTICEABLE COLD FRONT/DIRECTIONAL SHIFT LATE THIS AFTERNOON INTO THIS EVENING...CONFIDENCE IS BELOW AVERAGE REGARDING THE TIMING OF POTENTIAL MVFR CEILING DURING THE LATTER HALF OF THE PERIOD...AND WITH WHAT TIME FRAME(S) CARRIES THE HIGHEST POTENTIAL FOR SHOWER/THUNDERSTORM ACTIVITY. STARTING WITH THESE FIRST SEVERAL HOURS THIS AFTERNOON...DRY AND VFR CONDITIONS WILL PERSIST WITH A GENERALLY WESTERLY BREEZE LARGELY UNDER 12KT. STARTING AT 22Z AND LASTING THROUGH 06Z...HAVE INTRODUCED A GENERIC VICINITY THUNDERSTORM (VCTS) MENTION AS THIS SEEMS TO BE THE MAIN 8-HOUR WINDOW OF OPPORTUNITY FOR POSSIBLE STORMS NEAR THE TAF SITES (LATER UPDATES CAN "UPGRADE" TO TEMPO GROUPS AS NECESSARY). SHOULD ANY STORMS DIRECTLY AFFECT KGRI/KEAR...A PERIOD OF GUSTY WIND AND SMALL HAIL IS CERTAINLY POSSIBLE. AT LEAST FOR NOW...HAVE NOT MENTIONED ANY PRECIPITATION DURING THE 06Z-13Z TIME FRAME...BUT FROM 13Z ONWARD HAVE INTRODUCED AN MVFR CEILING ALONG WITH A GENERIC VICINITY SHOWERS (VCSH) MENTION. RE-VISITING SURFACE WIND TRENDS...ONCE THE COLD FRONT TRACKS THROUGH LATE THIS AFTERNOON/EVENING...A PREVAILING NORTH-NORTHEAST COMPONENT SETTLES IN WITH GUST POTENTIAL AT LEAST 15-20KT THROUGH THE REMAINDER OF THE PERIOD. && .CLIMATE... ISSUED AT 433 AM CDT SUN MAY 3 2015 PREDICTED HIGH TODAY: HASTINGS 91 GRAND ISLAND 91 RECORD HIGH: HASTINGS 89 (1959) GRAND ISLAND 92 (1959) && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...HEINLEIN LONG TERM...ADP AVIATION...PFANNKUCH CLIMATE...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1217 PM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 TODAY...STORMS SHOULD CONTINUE EASTWARD OUT OF THE FORECAST AREA EARLY THIS MORNING. HIGH RES MODELS ARE IN GOOD AGREEMENT WITH THAT. STORMS LAST EVENING DID PRODUCE SOME LARGE HAIL AND A FEW SPOTS RECEIVED STRONG WINDS AS STORMS MIXED DOWN A STRONG LOW LEVEL JET. AS OF AROUND 07Z RUC MODEL INITIALIZATION SHOWED WINDS AT AROUND 1 KM AGL OF AROUND 40-50 KNOTS STRETCHING FROM WESTERN OKLAHOMA INTO SOUTHEAST NEBRASKA AND PARTS OF IOWA. THESE WINDS WILL DECREASE THIS MORNING. COLD FRONT AS OF 08Z STRETCHED FROM NORTHEAST MINNESOTA BACK INTO WESTERN SOUTH DAKOTA. THAT FRONT WILL MOVE SOUTHEAST INTO NORTHEAST NEBRASKA THIS AFTERNOON. LOOK FOR HIGHS IN THE MID TO UPPER 80S AT MOST SPOTS TODAY WITH A FEW HIGHS AROUND 90 POSSIBLE. THIS WILL CREATE CAPE VALUES FROM 1500 TO 2500 J/KG BY MID AFTERNOON. EXPECT CAP TO BREAK NEAR THE FRONT BY MID/LATE AFTERNOON. SOME MODELS ALSO HINT AT THE CAP WEAKENING FARTHER SOUTH...BUT WITH A LACK OF FOCUS AT THAT TIME WILL KEEP HIGHEST POPS CLOSER TO THE FRONT. SOME SEVERE STORMS APPEAR POSSIBLE...WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. GENERALLY USED A BLEND OF SHORT RANGE GUIDANCE FOR TONIGHT WITH THE HIGHEST WEIGHT GIVEN TO THE 00Z HIGH RES WRF-ARW MODEL. LIKE SOME OF THE OTHER MODELS...IT DEVELOPED STORMS LATE AFTERNOON THEN MOVED THEM SOUTH AND EAST. SOME STORMS MAY CONTINUE TO BE SEVERE IN THE EVENING. COVERAGE SHOULD DECREASE AFTER MIDNIGHT. CONVECTION WILL LIKELY FORCE THE FRONT DOWN AT LEAST AS FAR AS SOUTHEAST NEBRASKA AND MAYBE INTO NORTHEAST KANSAS BY 12Z MONDAY. MOST MODELS SHOW LIFT OCCURRING OVER THE BOUNDARY DURING THE DAY MONDAY WITH PCPN COVERAGE INCREASING...SO HAVE POPS INCREASING TO MATCH THAT. TWO CLUSTERS OF STORMS MAY TAKE SHAPE BY LATE AFTERNOON OR EARLY EVENING. ONE NEAR THE NEBRASKA/SOUTH DAKOTA BORDER AND ANOTHER LIFTING FROM NORTHERN KANSAS THROUGH OUR AREA AND TOWARD CENTRAL IOWA MONDAY NIGHT. TUESDAY...WE MAY SEE SOMEWHAT OF A BREAK IN THE WIDESPREAD PCPN... AT LEAST OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. HAVE POPS RANGING FROM 15 TO 50 PERCENT...HIGHEST IN NORTHEAST NEBRASKA. SOUTHERLY FLOW WILL INCREASE AND HELP A WARM FRONT LIFT NORTH OF THE AREA. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 PATTERN WILL BE ACTIVE MUCH OF THIS PERIOD. A LARGE MID TROPOSPHERIC TROUGH SHOULD BE OVER THE WESTERN UNITED STATES AT THE START OF THIS PERIOD WITH EMBEDDED SHORTWAVES. ONE OF THESE WAVES WILL LIFT ACROSS MID AMERICA WEDNESDAY/WEDNESDAY NIGHT...WHILE A CLOSED LOW STARTS TO DIG SOUTHWARD FROM THE PACIFIC NORTHWEST. THIS WILL GENERALLY KEEP OUR AREA IN SOUTHWEST FLOW WITH A DECENT SUPPLY OF LOW LEVEL MOISTURE FOR SHOWERS AND STORMS TO WORK WITH. MODEL AGREEMENT STARTS TO FALL OFF BY DAY 7...SO CONFIDENCE FALLS TO AVERAGE BY DAY 7. TEMPERATURES AND PCPN SHOULD BE AT OR ABOVE NORMAL FOR THIS PERIOD. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1211 PM CDT SUN MAY 3 2015 SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE IN AREAL COVERAGE THIS AFTN ALONG A COLD FRONT PUSHING THRU ERN NEB. IT IS POSSIBLE THAT A FEW STORMS MAY APPROACH OR BECOME SEVERE LATE THIS AFTN. HAVE ADDED TEMPO GROUPS AT ALL TERMINALS FOR POSSIBLE LATE AFTN/EARLY EVENING MVFR CONDITIONS. VFR CONDITIONS THEN PREVAILING THIS EVENING THRU THE REST OF THE FCST PD. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...PEARSON/MILLER LONG TERM...MILLER AVIATION...DEE
AREA FORECAST DISCUSSION
NWS HASTINGS NE
924 AM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 924 AM CDT SUN MAY 3 2015 JUST UPDATED TO ADD A 2-3 HOUR WINDOW OF OPPORTUNITY FOR ISOLATED RAIN SHOWERS/WEAK THUNDERSTORMS TO SEVERAL COUNTIES MAINLY EAST OF AN OSBORNE-CLAY CENTER-OSCEOLA LINE THIS MORNING. ALTHOUGH FORCING IS SUBTLE...THIS RECENT UPTICK IN ELEVATED ACTIVITY APPEARS TO BE TIED TO A SUBTLE MID LEVEL PASSING THROUGH AND GENERATING "JUST ENOUGH" LOW-MID LEVEL THETA-E ADVECTION TO KICK THINGS OFF. ALTHOUGH MODELS HAVE STRUGGLED TO PICK UP ON THIS...WOULD BE SURPRISED TO SEE ANY OF THIS EASTERN ACTIVITY LINGER PAST THE 11AM-12PM HOUR...AS STILL EXPECT THE MAJORITY OF THE CWA TO REMAIN DRY THE MAJORITY OF THE DAY. AS FOR THE LATE AFTERNOON/EVENING/OVERNIGHT STORM CHANCES...UNFORTUNATELY...UNCERTAINTY MAY BE HIGHER IN THE NOW THAN IT WAS 24 HOURS AGO REGARDING HOW THIS PLAYS OUT. PER SOME MODELS...THE OVERALL SEVERE THREAT MAY BE A BIT LESS THAN THOUGHT 24 HOURS AGO...BUT THAT BEING SAID...GIVEN WHAT HAPPENED YESTERDAY WITH THE GREATER-THAN-EXPECTED COVERAGE OF STRONG- SEVERE STORMS IN THE NORTHEAST CWA...THIS PATTERN IS PRONE TO YIELDING SURPRISES. STAY TUNED FOR PLENTY MORE THOUGHTS/UPDATED THINKING WITH THE AFTERNOON DISCUSSION. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 433 AM CDT SUN MAY 3 2015 BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SPLIT FLOW FOR TODAY...CAUGHT BETWEEN THE NORTH AND SOUTH STREAMS. LOCAL SYNOPTIC FLOW WILL BE ZONAL...BUT TURN MORE SOUTHWEST TONIGHT AS A NEGATIVELY TILTED BROAD UPPER LEVEL TROUGH ENTERS THE SOUTHWESTERN UNITED STATES. AT THE SURFACE...A COLD FRONT IS ON ITS WAY SOUTH ACROSS SOUTH DAKOTA. THE TIMING OF THIS FRONT SUGGESTS THAT WE WILL WARM UP SIGNIFICANTLY DUE TO COMPRESSIONAL WARMING. MODELS ARE GENERALLY NOT PICKING UP ON THIS WELL ENOUGH...SO I AM GOING OUT ON A BIT OF A LIMB AND GOING QUITE A BIT MORE THAN GENERAL GUIDANCE IN THE MID 80S. GOING FOR 91 FOR THE TRI-CITIES...FAVORING THE HI RES NMM SOLUTION. BELIEVE IT OR NOT...THIS WOULD BREAK OUR RECORD IN HASTINGS BY 2 DEGREES AND BE ONE DEGREE SHORT OF THE RECORD HIGH IN GRAND ISLAND. THE RAP MODEL BUMPS UP TEMPERATURES EVEN MORE IN NORTH CENTRAL KANSAS TO THE MID 90S. THESE WARMER TEMPERATURES WOULD HAVE PUT US IN THE REALM OF APPROACHING CRITICAL FIRE WEATHER ISSUES IF IT WERE NOT FOR THE FACT THAT WE HAVE GREENED UP. CHANCES OF PRECIPITATION ARE NOT CERTAIN. COVERAGE IS A BIT SPOTTY UNTIL THE CAP BREAKS IN THE EVENING. EVENT THEN...COVERAGE IS IN QUESTION...ESPECIALLY DEPENDING ON THE EXACT PLACEMENT OF THE FRONT WHEN STORMS FIRE. WE WILL PROBABLY NEED A HIGHER NARROW CORRIDOR OF CATEGORICAL CHANCES OF SHOWERS/THUNDERSTORMS...BUT AT THIS TIME...THAT IS VERY DIFFICULT TO DETERMINE...ESPECIALLY AS THE FRONT MAY TEMPORARILY STALL FOR A SHORT TIME TOWARD EVENING. A SECONDARY IMPULSE WITHIN MID-LEVEL FLOW COULD BOOST CHANCES OF RAIN OVERNIGHT...PROBABLY IN OUR SOUTH. I DO NOT GO OVER A 60 PERCENT CHANCE ANYWHERE IN THE CWA...AND HANG AROUND 40-50 PERCENT CHANCE FOR THE TRI-CITIES. AS FOR STRONG/SEVERE CHANCES...WE COULD GET SOME STRONG STORMS WITH MARGINAL INSTABILITY OF 500 TO 1500 J/KG AND LOW- LEVEL WIND SHEAR APPROACHING 30-35 IN OUR NORTH...BUT PROBABLY LOWER IN MOST OF THE REST OF THE CWA. THIS COULD BE ENOUGH TO GIVE US SOME STRONG STORMS WITH NICKEL SIZE HAIL AND PERHAPS A STRONG WIND GUST...BUT THE BETTER SUPPORT FOR SEVERE WEATHER LOOKS LIKE IT SHOULD BE EAST/NORTHEAST OF THE CWA. WENT WITH SIMILAR LOWS FOR TONIGHT COMPARED TO THE PREVIOUS FORECAST AND STUCK WITH SUPERBLEND IN THE 50S. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 433 AM CDT SUN MAY 3 2015 PRIMARY FORECAST CONCERN CONTINUES TO REVOLVE AROUND THE MULTIPLE CHANCES FOR THUNDERSTORMS THROUGH THE ENTIRE PERIOD. THE UNSETTLED WEATHER PATTERN HAS SETTLED IN ACROSS THE REGION BY THE START OF THE PERIOD MON/MON NIGHT...WITH MODELS SHOWING THE AREA UNDER SOUTHWESTERLY FLOW ALOFT...WITH THE PARENT LOW PRESSURE OVER SRN CALIFORNIA AND WEAK RIDGING EXTENDING NORTH FROM THE GULF COAST INTO PORTIONS OF THE MIDWEST. MAY HAVE SOME LINGERING PRECIP ACROSS THE AREA DURING THE MORNING HOURS FROM OVERNIGHT ACTIVITY...BUT WOULD THINK THERE WOULD BE A LULL AT SOME POINT. HARD TO PINPOINT EXACTLY WHERE THAT LINGERING ACTIVITY MAY BE...SO HAVE CHANCE POPS ACROSS THE ENTIRE CWA. AT THE SFC...MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT SHOWING THE PLACEMENT OF THE MAIN SFC FRONT OVER SRN PORTIONS OF THE CWA NEAR THE NEB/KS STATE LINE...WITH SOME SHOWING A LOW PLACED IN CLOSE PROXIMITY TO THE S/SWRN CORNER OF THE CWA. THE PLACEMENT OF THE SFC FRONT...UNCERTAINTY WITH THE AMOUNT OF SKY COVER /LIKELY HIGH/ AND ANY LINGERING PRECIP MAKES THE HIGH TEMP FORECAST TRICKY. MUCH OF SC NEB IS LOOKING AT ERLY WINDS NORTH OF THE FRONT...WITH MORE SRLY WINDS ACROSS NC KS. FORECAST HIGH TEMP IS A BLEND...AND COULD SEE CLOSE TO A 20 DEGREE GRADIENT ACROSS THE CWA /SOME MODELS ARE MORE DRASTIC/...WITH ARND 60 IN THE NORTH TO NEAR 80 IN THE FAR SOUTH. DURING THE AFTERNOON HOURS AND INTO THE EVENING/OVERNIGHT...THIS FRONTAL BOUNDARY WILL BE A FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT AS YET ANOTHER DISTURBANCE MAKES ITS WAY INTO THE REGION...AIDED ALSO BY AN INCREASING LLJ. SEVERE WEATHER REMAINS A CONCERN WITH MODEST INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR...LARGE HAIL/DAMAGING WINDS REMAIN THE PRIMARY CONCERNS...BUT WILL HAVE TO MONITOR THE POTENTIAL FOR AN ISOLATED TORNADO WITH THOSE MORE ERLY WINDS/INCREASED LOW LEVEL SHEAR IN THE AREA. SPC DAY 2 OUTLOOK SLIGHT RISK AREA INCLUDES ROUGHLY THE SERN HALF OF THE CWA. SIMILAR TO MONDAY...TUESDAY MORNING MAY HAVE SOME LINGERING ACTIVITY FROM OVERNIGHT...BUT MODELS SUGGEST THE OVERALL COVERAGE MAY NOT BE AS WIDESPREAD. THE MAIN UPPER LEVEL LOW HAS SHIFTED EAST INTO THE FOUR CORNERS REGION BY TUESDAY MORNING...AND MODELS CONTINUE TO SHOW THE POTENTIAL FOR THE LOW TO WEAKEN SOME/FILL...AS IT COMES UNDER INCREASING INFLUENCE OF A STRONGER UPPER LEVEL LOW MOVING INTO THE PAC NW REGION. AT THE SFC...DURING THE DAYTIME HOURS...THE FRONTAL BOUNDARY CONTINUING TO MEANDER AROUND CENTRAL PORTIONS OF THE CWA LOOKS TO PUSH NORTH AS A WARM FRONT...WITH MOST MODELS SHOWING SRLY WINDS IN PLACE ACROSS THE ENTIRE CWA DURING THE AFTERNOON. MODELS CONTINUE TO SHOW THE BETTER THUNDERSTORMS CHANCES ACROSS WRN PORTIONS OF THE CWA DURING THE AFTERNOON...SPREADING ACROSS THE REST OF THE CWA OVERNIGHT AS LIFT CONTINUES TO INCREASE WITH THE APPROACHING MAIN UPPER TROUGH/LOW...WHICH IS STARTING TO MAKE MORE OF A PUSH ONTO THE THE PLAINS DURING THE LATE TUES NIGHT HOURS/WED MORNING. WED/WED NIGHT CONTINUES TO BE THE PERIOD GENERALLY SHOWN BY MODELS WHEN THAT MAIN TROUGH AXIS /CLOSED LOW?/ MAKES ITS TREK NE THROUGH THE REGION...AS THAT STRONGER UPPER LEVEL LOW DIGS FURTHER SOUTH ALONG THE WEST COAST. THE HIGH CHANCE/LOW END LIKELY POPS CONTINUE IN THE FORECAST...SIMILAR TO PERIODS PRIOR AND FOLLOWING...HARD TO TRIM AREAS OUT OR RAISE POPS IN OTHERS WHEN SO MANY DETAILS HAVE YET TO BE IRONED OUT. THE LOCATION OF THE SFC LOW/ASSOCIATED BOUNDARIES LOOK TO BE PLAYING A BIGGER ROLE/FOCUS FOR CONVECTIVE DEVELOPMENT NEAR/ACROSS THE CWA...SO AS THEIR ULTIMATE PLACEMENT BECOMES MORE CLEAR IN THE COMING MODEL RUNS...CAN PIN DOWN BETTER DETAILS WITH POPS AND SEVERE WEATHER POTENTIAL. THROUGH THE REST OF THE LONG TERM PERIOD THURSDAY THROUGH SATURDAY...ONE NOTABLE DISTURBANCE MOVES OUT...BUT SOUTHWESTERLY FLOW REMAINS IN PLACE IN THE UPPER LEVEL AS THAT NEXT LOW PRESSURE SYSTEM CONTINUES TO DIG FURTHER SOUTH INTO CALIFORNIA. PIECES OF SHORTWAVE ENERGY ASSOCIATED WITH THAT LOW LOOK TO CONTINUE TO BRING AT LEAST PERIODIC THUNDERSTORM CHANCES...KEPT THE FORECAST CLOSE TO THE CR INIT/SUPERBLEND OUTPUT. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 541 AM CDT SUN MAY 3 2015 WIND WILL BE PRIMARILY OUT OF THE SOUTH BEFORE A COLD FRONT MOVES IN BY THIS EVENING...AND SHIFTS TO THE NORTH...WHEN SHOWERS/THUNDERSTORMS WILL BE POSSIBLE. TIMING OF ANY THUNDERSTORMS IS SO UNCERTAIN...THAT A RATHER GENERAL VCTS WAS INCLUDED FOR 00Z AND BEYOND. && .CLIMATE... ISSUED AT 433 AM CDT SUN MAY 3 2015 PREDICTED HIGH TODAY: HASTINGS 91 GRAND ISLAND 91 RECORD HIGH: HASTINGS 89 (1959) GRAND ISLAND 92 (1959) && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...HEINLEIN LONG TERM...ADP AVIATION...HEINLEIN CLIMATE...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
637 AM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 TODAY...STORMS SHOULD CONTINUE EASTWARD OUT OF THE FORECAST AREA EARLY THIS MORNING. HIGH RES MODELS ARE IN GOOD AGREEMENT WITH THAT. STORMS LAST EVENING DID PRODUCE SOME LARGE HAIL AND A FEW SPOTS RECEIVED STRONG WINDS AS STORMS MIXED DOWN A STRONG LOW LEVEL JET. AS OF AROUND 07Z RUC MODEL INITIALIZATION SHOWED WINDS AT AROUND 1 KM AGL OF AROUND 40-50 KNOTS STRETCHING FROM WESTERN OKLAHOMA INTO SOUTHEAST NEBRASKA AND PARTS OF IOWA. THESE WINDS WILL DECREASE THIS MORNING. COLD FRONT AS OF 08Z STRETCHED FROM NORTHEAST MINNESOTA BACK INTO WESTERN SOUTH DAKOTA. THAT FRONT WILL MOVE SOUTHEAST INTO NORTHEAST NEBRASKA THIS AFTERNOON. LOOK FOR HIGHS IN THE MID TO UPPER 80S AT MOST SPOTS TODAY WITH A FEW HIGHS AROUND 90 POSSIBLE. THIS WILL CREATE CAPE VALUES FROM 1500 TO 2500 J/KG BY MID AFTERNOON. EXPECT CAP TO BREAK NEAR THE FRONT BY MID/LATE AFTERNOON. SOME MODELS ALSO HINT AT THE CAP WEAKENING FARTHER SOUTH...BUT WITH A LACK OF FOCUS AT THAT TIME WILL KEEP HIGHEST POPS CLOSER TO THE FRONT. SOME SEVERE STORMS APPEAR POSSIBLE...WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. GENERALLY USED A BLEND OF SHORT RANGE GUIDANCE FOR TONIGHT WITH THE HIGHEST WEIGHT GIVEN TO THE 00Z HIGH RES WRF-ARW MODEL. LIKE SOME OF THE OTHER MODELS...IT DEVELOPED STORMS LATE AFTERNOON THEN MOVED THEM SOUTH AND EAST. SOME STORMS MAY CONTINUE TO BE SEVERE IN THE EVENING. COVERAGE SHOULD DECREASE AFTER MIDNIGHT. CONVECTION WILL LIKELY FORCE THE FRONT DOWN AT LEAST AS FAR AS SOUTHEAST NEBRASKA AND MAYBE INTO NORTHEAST KANSAS BY 12Z MONDAY. MOST MODELS SHOW LIFT OCCURRING OVER THE BOUNDARY DURING THE DAY MONDAY WITH PCPN COVERAGE INCREASING...SO HAVE POPS INCREASING TO MATCH THAT. TWO CLUSTERS OF STORMS MAY TAKE SHAPE BY LATE AFTERNOON OR EARLY EVENING. ONE NEAR THE NEBRASKA/SOUTH DAKOTA BORDER AND ANOTHER LIFTING FROM NORTHERN KANSAS THROUGH OUR AREA AND TOWARD CENTRAL IOWA MONDAY NIGHT. TUESDAY...WE MAY SEE SOMEWHAT OF A BREAK IN THE WIDESPREAD PCPN... AT LEAST OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. HAVE POPS RANGING FROM 15 TO 50 PERCENT...HIGHEST IN NORTHEAST NEBRASKA. SOUTHERLY FLOW WILL INCREASE AND HELP A WARM FRONT LIFT NORTH OF THE AREA. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 PATTERN WILL BE ACTIVE MUCH OF THIS PERIOD. A LARGE MID TROPOSPHERIC TROUGH SHOULD BE OVER THE WESTERN UNITED STATES AT THE START OF THIS PERIOD WITH EMBEDDED SHORTWAVES. ONE OF THESE WAVES WILL LIFT ACROSS MID AMERICA WEDNESDAY/WEDNESDAY NIGHT...WHILE A CLOSED LOW STARTS TO DIG SOUTHWARD FROM THE PACIFIC NORTHWEST. THIS WILL GENERALLY KEEP OUR AREA IN SOUTHWEST FLOW WITH A DECENT SUPPLY OF LOW LEVEL MOISTURE FOR SHOWERS AND STORMS TO WORK WITH. MODEL AGREEMENT STARTS TO FALL OFF BY DAY 7...SO CONFIDENCE FALLS TO AVERAGE BY DAY 7. TEMPERATURES AND PCPN SHOULD BE AT OR ABOVE NORMAL FOR THIS PERIOD. && .AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 637 AM CDT SUN MAY 3 2015 A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA THIS AFTERNOON AND EARLY EVENING. LOOK FOR GUSTY SOUTH WINDS AHEAD OF THE FRONT. SHOWERS AND THUNDERSTORMS SHOULD DEVELOP THIS EVENING AND CONTINUE INTO THE EARLY OVERNIGHT HOURS. A LOT OF LOW-LEVEL MOISTURE IS FORECAST TO REMAIN BEHIND TODAY`S FRONT...THUS HAVE KEPT MVFR CEILINGS IN THE FORECAST THROUGH 12Z MONDAY. WITH SEVERAL WEATHER SYSTEMS EXPECTED TO MOVE THROUGH THIS COMING WEEK EXPECT UNSETTLED WEATHER TO CONTINUE OFF AND ON THROUGH THE WORK WEEK. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...PEARSON/MILLER LONG TERM...MILLER AVIATION...PEARSON
AREA FORECAST DISCUSSION
NWS HASTINGS NE
543 AM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 433 AM CDT SUN MAY 3 2015 BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SPLIT FLOW FOR TODAY...CAUGHT BETWEEN THE NORTH AND SOUTH STREAMS. LOCAL SYNOPTIC FLOW WILL BE ZONAL...BUT TURN MORE SOUTHWEST TONIGHT AS A NEGATIVELY TILTED BROAD UPPER LEVEL TROUGH ENTERS THE SOUTHWESTERN UNITED STATES. AT THE SURFACE...A COLD FRONT IS ON ITS WAY SOUTH ACROSS SOUTH DAKOTA. THE TIMING OF THIS FRONT SUGGESTS THAT WE WILL WARM UP SIGNIFICANTLY DUE TO COMPRESSIONAL WARMING. MODELS ARE GENERALLY NOT PICKING UP ON THIS WELL ENOUGH...SO I AM GOING OUT ON A BIT OF A LIMB AND GOING QUITE A BIT MORE THAN GENERAL GUIDANCE IN THE MID 80S. GOING FOR 91 FOR THE TRI-CITIES...FAVORING THE HI RES NMM SOLUTION. BELIEVE IT OR NOT...THIS WOULD BREAK OUR RECORD IN HASTINGS BY 2 DEGREES AND BE ONE DEGREE SHORT OF THE RECORD HIGH IN GRAND ISLAND. THE RAP MODEL BUMPS UP TEMPERATURES EVEN MORE IN NORTH CENTRAL KANSAS TO THE MID 90S. THESE WARMER TEMPERATURES WOULD HAVE PUT US IN THE REALM OF APPROACHING CRITICAL FIRE WEATHER ISSUES IF IT WERE NOT FOR THE FACT THAT WE HAVE GREENED UP. CHANCES OF PRECIPITATION ARE NOT CERTAIN. COVERAGE IS A BIT SPOTTY UNTIL THE CAP BREAKS IN THE EVENING. EVENT THEN...COVERAGE IS IN QUESTION...ESPECIALLY DEPENDING ON THE EXACT PLACEMENT OF THE FRONT WHEN STORMS FIRE. WE WILL PROBABLY NEED A HIGHER NARROW CORRIDOR OF CATEGORICAL CHANCES OF SHOWERS/THUNDERSTORMS...BUT AT THIS TIME...THAT IS VERY DIFFICULT TO DETERMINE...ESPECIALLY AS THE FRONT MAY TEMPORARILY STALL FOR A SHORT TIME TOWARD EVENING. A SECONDARY IMPULSE WITHIN MID-LEVEL FLOW COULD BOOST CHANCES OF RAIN OVERNIGHT...PROBABLY IN OUR SOUTH. I DO NOT GO OVER A 60 PERCENT CHANCE ANYWHERE IN THE CWA...AND HANG AROUND 40-50 PERCENT CHANCE FOR THE TRI-CITIES. AS FOR STRONG/SEVERE CHANCES...WE COULD GET SOME STRONG STORMS WITH MARGINAL INSTABILITY OF 500 TO 1500 J/KG AND LOW- LEVEL WIND SHEAR APPROACHING 30-35 IN OUR NORTH...BUT PROBABLY LOWER IN MOST OF THE REST OF THE CWA. THIS COULD BE ENOUGH TO GIVE US SOME STRONG STORMS WITH NICKEL SIZE HAIL AND PERHAPS A STRONG WIND GUST...BUT THE BETTER SUPPORT FOR SEVERE WEATHER LOOKS LIKE IT SHOULD BE EAST/NORTHEAST OF THE CWA. WENT WITH SIMILAR LOWS FOR TONIGHT COMPARED TO THE PREVIOUS FORECAST AND STUCK WITH SUPERBLEND IN THE 50S. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 433 AM CDT SUN MAY 3 2015 PRIMARY FORECAST CONCERN CONTINUES TO REVOLVE AROUND THE MULTIPLE CHANCES FOR THUNDERSTORMS THROUGH THE ENTIRE PERIOD. THE UNSETTLED WEATHER PATTERN HAS SETTLED IN ACROSS THE REGION BY THE START OF THE PERIOD MON/MON NIGHT...WITH MODELS SHOWING THE AREA UNDER SOUTHWESTERLY FLOW ALOFT...WITH THE PARENT LOW PRESSURE OVER SRN CALIFORNIA AND WEAK RIDGING EXTENDING NORTH FROM THE GULF COAST INTO PORTIONS OF THE MIDWEST. MAY HAVE SOME LINGERING PRECIP ACROSS THE AREA DURING THE MORNING HOURS FROM OVERNIGHT ACTIVITY...BUT WOULD THINK THERE WOULD BE A LULL AT SOME POINT. HARD TO PINPOINT EXACTLY WHERE THAT LINGERING ACTIVITY MAY BE...SO HAVE CHANCE POPS ACROSS THE ENTIRE CWA. AT THE SFC...MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT SHOWING THE PLACEMENT OF THE MAIN SFC FRONT OVER SRN PORTIONS OF THE CWA NEAR THE NEB/KS STATE LINE...WITH SOME SHOWING A LOW PLACED IN CLOSE PROXIMITY TO THE S/SWRN CORNER OF THE CWA. THE PLACEMENT OF THE SFC FRONT...UNCERTAINTY WITH THE AMOUNT OF SKY COVER /LIKELY HIGH/ AND ANY LINGERING PRECIP MAKES THE HIGH TEMP FORECAST TRICKY. MUCH OF SC NEB IS LOOKING AT ERLY WINDS NORTH OF THE FRONT...WITH MORE SRLY WINDS ACROSS NC KS. FORECAST HIGH TEMP IS A BLEND...AND COULD SEE CLOSE TO A 20 DEGREE GRADIENT ACROSS THE CWA /SOME MODELS ARE MORE DRASTIC/...WITH ARND 60 IN THE NORTH TO NEAR 80 IN THE FAR SOUTH. DURING THE AFTERNOON HOURS AND INTO THE EVENING/OVERNIGHT...THIS FRONTAL BOUNDARY WILL BE A FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT AS YET ANOTHER DISTURBANCE MAKES ITS WAY INTO THE REGION...AIDED ALSO BY AN INCREASING LLJ. SEVERE WEATHER REMAINS A CONCERN WITH MODEST INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR...LARGE HAIL/DAMAGING WINDS REMAIN THE PRIMARY CONCERNS...BUT WILL HAVE TO MONITOR THE POTENTIAL FOR AN ISOLATED TORNADO WITH THOSE MORE ERLY WINDS/INCREASED LOW LEVEL SHEAR IN THE AREA. SPC DAY 2 OUTLOOK SLIGHT RISK AREA INCLUDES ROUGHLY THE SERN HALF OF THE CWA. SIMILAR TO MONDAY...TUESDAY MORNING MAY HAVE SOME LINGERING ACTIVITY FROM OVERNIGHT...BUT MODELS SUGGEST THE OVERALL COVERAGE MAY NOT BE AS WIDESPREAD. THE MAIN UPPER LEVEL LOW HAS SHIFTED EAST INTO THE FOUR CORNERS REGION BY TUESDAY MORNING...AND MODELS CONTINUE TO SHOW THE POTENTIAL FOR THE LOW TO WEAKEN SOME/FILL...AS IT COMES UNDER INCREASING INFLUENCE OF A STRONGER UPPER LEVEL LOW MOVING INTO THE PAC NW REGION. AT THE SFC...DURING THE DAYTIME HOURS...THE FRONTAL BOUNDARY CONTINUING TO MEANDER AROUND CENTRAL PORTIONS OF THE CWA LOOKS TO PUSH NORTH AS A WARM FRONT...WITH MOST MODELS SHOWING SRLY WINDS IN PLACE ACROSS THE ENTIRE CWA DURING THE AFTERNOON. MODELS CONTINUE TO SHOW THE BETTER THUNDERSTORMS CHANCES ACROSS WRN PORTIONS OF THE CWA DURING THE AFTERNOON...SPREADING ACROSS THE REST OF THE CWA OVERNIGHT AS LIFT CONTINUES TO INCREASE WITH THE APPROACHING MAIN UPPER TROUGH/LOW...WHICH IS STARTING TO MAKE MORE OF A PUSH ONTO THE THE PLAINS DURING THE LATE TUES NIGHT HOURS/WED MORNING. WED/WED NIGHT CONTINUES TO BE THE PERIOD GENERALLY SHOWN BY MODELS WHEN THAT MAIN TROUGH AXIS /CLOSED LOW?/ MAKES ITS TREK NE THROUGH THE REGION...AS THAT STRONGER UPPER LEVEL LOW DIGS FURTHER SOUTH ALONG THE WEST COAST. THE HIGH CHANCE/LOW END LIKELY POPS CONTINUE IN THE FORECAST...SIMILAR TO PERIODS PRIOR AND FOLLOWING...HARD TO TRIM AREAS OUT OR RAISE POPS IN OTHERS WHEN SO MANY DETAILS HAVE YET TO BE IRONED OUT. THE LOCATION OF THE SFC LOW/ASSOCIATED BOUNDARIES LOOK TO BE PLAYING A BIGGER ROLE/FOCUS FOR CONVECTIVE DEVELOPMENT NEAR/ACROSS THE CWA...SO AS THEIR ULTIMATE PLACEMENT BECOMES MORE CLEAR IN THE COMING MODEL RUNS...CAN PIN DOWN BETTER DETAILS WITH POPS AND SEVERE WEATHER POTENTIAL. THROUGH THE REST OF THE LONG TERM PERIOD THURSDAY THROUGH SATURDAY...ONE NOTABLE DISTURBANCE MOVES OUT...BUT SOUTHWESTERLY FLOW REMAINS IN PLACE IN THE UPPER LEVEL AS THAT NEXT LOW PRESSURE SYSTEM CONTINUES TO DIG FURTHER SOUTH INTO CALIFORNIA. PIECES OF SHORTWAVE ENERGY ASSOCIATED WITH THAT LOW LOOK TO CONTINUE TO BRING AT LEAST PERIODIC THUNDERSTORM CHANCES...KEPT THE FORECAST CLOSE TO THE CR INIT/SUPERBLEND OUTPUT. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 541 AM CDT SUN MAY 3 2015 WIND WILL BE PRIMARILY OUT OF THE SOUTH BEFORE A COLD FRONT MOVES IN BY THIS EVENING...AND SHIFTS TO THE NORTH...WHEN SHOWERS/THUNDERSTORMS WILL BE POSSIBLE. TIMING OF ANY THUNDERSTORMS IS SO UNCERTAIN...THAT A RATHER GENERAL VCTS WAS INCLUDED FOR 00Z AND BEYOND. && .CLIMATE... ISSUED AT 433 AM CDT SUN MAY 3 2015 PREDICTED HIGH TODAY: HASTINGS 91 GRAND ISLAND 91 RECORD HIGH: HASTINGS 89 (1959) GRAND ISLAND 92 (1959) && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...ADP AVIATION...HEINLEIN CLIMATE...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
436 AM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 433 AM CDT SUN MAY 3 2015 BIGGEST CHALLENGE WILL BE DETERMINING CHANCES AND TIMING OF SHOWERS/THUNDERSTORMS AS WELL AS THE POTENTIAL FOR STRONG STORMS. ANOTHER CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES FOR TODAY. SPLIT FLOW FOR TODAY...CAUGHT BETWEEN THE NORTH AND SOUTH STREAMS. LOCAL SYNOPTIC FLOW WILL BE ZONAL...BUT TURN MORE SOUTHWEST TONIGHT AS A NEGATIVELY TILTED BROAD UPPER LEVEL TROUGH ENTERS THE SOUTHWESTERN UNITED STATES. AT THE SURFACE...A COLD FRONT IS ON ITS WAY SOUTH ACROSS SOUTH DAKOTA. THE TIMING OF THIS FRONT SUGGESTS THAT WE WILL WARM UP SIGNIFICANTLY DUE TO COMPRESSIONAL WARMING. MODELS ARE GENERALLY NOT PICKING UP ON THIS WELL ENOUGH...SO I AM GOING OUT ON A BIT OF A LIMB AND GOING QUITE A BIT MORE THAN GENERAL GUIDANCE IN THE MID 80S. GOING FOR 91 FOR THE TRI-CITIES...FAVORING THE HI RES NMM SOLUTION. BELIEVE IT OR NOT...THIS WOULD BREAK OUR RECORD IN HASTINGS BY 2 DEGREES AND BE ONE DEGREE SHORT OF THE RECORD HIGH IN GRAND ISLAND. THE RAP MODEL BUMPS UP TEMPERATURES EVEN MORE IN NORTH CENTRAL KANSAS TO THE MID 90S. THESE WARMER TEMPERATURES WOULD HAVE PUT US IN THE REALM OF APPROACHING CRITICAL FIRE WEATHER ISSUES IF IT WERE NOT FOR THE FACT THAT WE HAVE GREENED UP. CHANCES OF PRECIPITATION ARE NOT CERTAIN. COVERAGE IS A BIT SPOTTY UNTIL THE CAP BREAKS IN THE EVENING. EVENT THEN...COVERAGE IS IN QUESTION...ESPECIALLY DEPENDING ON THE EXACT PLACEMENT OF THE FRONT WHEN STORMS FIRE. WE WILL PROBABLY NEED A HIGHER NARROW CORRIDOR OF CATEGORICAL CHANCES OF SHOWERS/THUNDERSTORMS...BUT AT THIS TIME...THAT IS VERY DIFFICULT TO DETERMINE...ESPECIALLY AS THE FRONT MAY TEMPORARILY STALL FOR A SHORT TIME TOWARD EVENING. A SECONDARY IMPULSE WITHIN MID-LEVEL FLOW COULD BOOST CHANCES OF RAIN OVERNIGHT...PROBABLY IN OUR SOUTH. I DO NOT GO OVER A 60 PERCENT CHANCE ANYWHERE IN THE CWA...AND HANG AROUND 40-50 PERCENT CHANCE FOR THE TRI-CITIES. AS FOR STRONG/SEVERE CHANCES...WE COULD GET SOME STRONG STORMS WITH MARGINAL INSTABILITY OF 500 TO 1500 J/KG AND LOW- LEVEL WIND SHEAR APPROACHING 30-35 IN OUR NORTH...BUT PROBABLY LOWER IN MOST OF THE REST OF THE CWA. THIS COULD BE ENOUGH TO GIVE US SOME STRONG STORMS WITH NICKEL SIZE HAIL AND PERHAPS A STRONG WIND GUST...BUT THE BETTER SUPPORT FOR SEVERE WEATHER LOOKS LIKE IT SHOULD BE EAST/NORTHEAST OF THE CWA. WENT WITH SIMILAR LOWS FOR TONIGHT COMPARED TO THE PREVIOUS FORECAST AND STUCK WITH SUPERBLEND IN THE 50S. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 433 AM CDT SUN MAY 3 2015 PRIMARY FORECAST CONCERN CONTINUES TO REVOLVE AROUND THE MULTIPLE CHANCES FOR THUNDERSTORMS THROUGH THE ENTIRE PERIOD. THE UNSETTLED WEATHER PATTERN HAS SETTLED IN ACROSS THE REGION BY THE START OF THE PERIOD MON/MON NIGHT...WITH MODELS SHOWING THE AREA UNDER SOUTHWESTERLY FLOW ALOFT...WITH THE PARENT LOW PRESSURE OVER SRN CALIFORNIA AND WEAK RIDGING EXTENDING NORTH FROM THE GULF COAST INTO PORTIONS OF THE MIDWEST. MAY HAVE SOME LINGERING PRECIP ACROSS THE AREA DURING THE MORNING HOURS FROM OVERNIGHT ACTIVITY...BUT WOULD THINK THERE WOULD BE A LULL AT SOME POINT. HARD TO PINPOINT EXACTLY WHERE THAT LINGERING ACTIVITY MAY BE...SO HAVE CHANCE POPS ACROSS THE ENTIRE CWA. AT THE SFC...MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT SHOWING THE PLACEMENT OF THE MAIN SFC FRONT OVER SRN PORTIONS OF THE CWA NEAR THE NEB/KS STATE LINE...WITH SOME SHOWING A LOW PLACED IN CLOSE PROXIMITY TO THE S/SWRN CORNER OF THE CWA. THE PLACEMENT OF THE SFC FRONT...UNCERTAINTY WITH THE AMOUNT OF SKY COVER /LIKELY HIGH/ AND ANY LINGERING PRECIP MAKES THE HIGH TEMP FORECAST TRICKY. MUCH OF SC NEB IS LOOKING AT ERLY WINDS NORTH OF THE FRONT...WITH MORE SRLY WINDS ACROSS NC KS. FORECAST HIGH TEMP IS A BLEND...AND COULD SEE CLOSE TO A 20 DEGREE GRADIENT ACROSS THE CWA /SOME MODELS ARE MORE DRASTIC/...WITH ARND 60 IN THE NORTH TO NEAR 80 IN THE FAR SOUTH. DURING THE AFTERNOON HOURS AND INTO THE EVENING/OVERNIGHT...THIS FRONTAL BOUNDARY WILL BE A FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT AS YET ANOTHER DISTURBANCE MAKES ITS WAY INTO THE REGION...AIDED ALSO BY AN INCREASING LLJ. SEVERE WEATHER REMAINS A CONCERN WITH MODEST INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR...LARGE HAIL/DAMAGING WINDS REMAIN THE PRIMARY CONCERNS...BUT WILL HAVE TO MONITOR THE POTENTIAL FOR AN ISOLATED TORNADO WITH THOSE MORE ERLY WINDS/INCREASED LOW LEVEL SHEAR IN THE AREA. SPC DAY 2 OUTLOOK SLIGHT RISK AREA INCLUDES ROUGHLY THE SERN HALF OF THE CWA. SIMILAR TO MONDAY...TUESDAY MORNING MAY HAVE SOME LINGERING ACTIVITY FROM OVERNIGHT...BUT MODELS SUGGEST THE OVERALL COVERAGE MAY NOT BE AS WIDESPREAD. THE MAIN UPPER LEVEL LOW HAS SHIFTED EAST INTO THE FOUR CORNERS REGION BY TUESDAY MORNING...AND MODELS CONTINUE TO SHOW THE POTENTIAL FOR THE LOW TO WEAKEN SOME/FILL...AS IT COMES UNDER INCREASING INFLUENCE OF A STRONGER UPPER LEVEL LOW MOVING INTO THE PAC NW REGION. AT THE SFC...DURING THE DAYTIME HOURS...THE FRONTAL BOUNDARY CONTINUING TO MEANDER AROUND CENTRAL PORTIONS OF THE CWA LOOKS TO PUSH NORTH AS A WARM FRONT...WITH MOST MODELS SHOWING SRLY WINDS IN PLACE ACROSS THE ENTIRE CWA DURING THE AFTERNOON. MODELS CONTINUE TO SHOW THE BETTER THUNDERSTORMS CHANCES ACROSS WRN PORTIONS OF THE CWA DURING THE AFTERNOON...SPREADING ACROSS THE REST OF THE CWA OVERNIGHT AS LIFT CONTINUES TO INCREASE WITH THE APPROACHING MAIN UPPER TROUGH/LOW...WHICH IS STARTING TO MAKE MORE OF A PUSH ONTO THE THE PLAINS DURING THE LATE TUES NIGHT HOURS/WED MORNING. WED/WED NIGHT CONTINUES TO BE THE PERIOD GENERALLY SHOWN BY MODELS WHEN THAT MAIN TROUGH AXIS /CLOSED LOW?/ MAKES ITS TREK NE THROUGH THE REGION...AS THAT STRONGER UPPER LEVEL LOW DIGS FURTHER SOUTH ALONG THE WEST COAST. THE HIGH CHANCE/LOW END LIKELY POPS CONTINUE IN THE FORECAST...SIMILAR TO PERIODS PRIOR AND FOLLOWING...HARD TO TRIM AREAS OUT OR RAISE POPS IN OTHERS WHEN SO MANY DETAILS HAVE YET TO BE IRONED OUT. THE LOCATION OF THE SFC LOW/ASSOCIATED BOUNDARIES LOOK TO BE PLAYING A BIGGER ROLE/FOCUS FOR CONVECTIVE DEVELOPMENT NEAR/ACROSS THE CWA...SO AS THEIR ULTIMATE PLACEMENT BECOMES MORE CLEAR IN THE COMING MODEL RUNS...CAN PIN DOWN BETTER DETAILS WITH POPS AND SEVERE WEATHER POTENTIAL. THROUGH THE REST OF THE LONG TERM PERIOD THURSDAY THROUGH SATURDAY...ONE NOTABLE DISTURBANCE MOVES OUT...BUT SOUTHWESTERLY FLOW REMAINS IN PLACE IN THE UPPER LEVEL AS THAT NEXT LOW PRESSURE SYSTEM CONTINUES TO DIG FURTHER SOUTH INTO CALIFORNIA. PIECES OF SHORTWAVE ENERGY ASSOCIATED WITH THAT LOW LOOK TO CONTINUE TO BRING AT LEAST PERIODIC THUNDERSTORM CHANCES...KEPT THE FORECAST CLOSE TO THE CR INIT/SUPERBLEND OUTPUT. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1257 AM CDT SUN MAY 3 2015 WIND SHEAR WILL BE A CONCERN FOR THE FIRST FEW HOURS DURING THE OVERNIGHT...BUT SHOULD WANE FROM WEST TO EAST AS THE LOW-LEVEL JET MOVES EAST. ANY CLOUDS SHOULD REMAIN PRIMARILY MID-HIGH LEVEL OVERNIGHT INTO SUNDAY. AS A COLD FRONT APPROACHES FROM THE NORTH...THERE WILL BE AN INCREASED CHANCE OF SHOWERS/T-STORMS. && .CLIMATE... ISSUED AT 433 AM CDT SUN MAY 3 2015 PREDICTED HIGH TODAY: HASTINGS 91 GRAND ISLAND 91 RECORD HIGH: HASTINGS 89 (1959) GRAND ISLAND 92 (1959) && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...ADP AVIATION...HEINLEIN CLIMATE...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
322 AM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 TODAY...STORMS SHOULD CONTINUE EASTWARD OUT OF THE FORECAST AREA EARLY THIS MORNING. HIGH RES MODELS ARE IN GOOD AGREEMENT WITH THAT. STORMS LAST EVENING DID PRODUCE SOME LARGE HAIL AND A FEW SPOTS RECEIVED STRONG WINDS AS STORMS MIXED DOWN A STRONG LOW LEVEL JET. AS OF AROUND 07Z RUC MODEL INITIALIZATION SHOWED WINDS AT AROUND 1 KM AGL OF AROUND 40-50 KNOTS STRETCHING FROM WESTERN OKLAHOMA INTO SOUTHEAST NEBRASKA AND PARTS OF IOWA. THESE WINDS WILL DECREASE THIS MORNING. COLD FRONT AS OF 08Z STRETCHED FROM NORTHEAST MINNESOTA BACK INTO WESTERN SOUTH DAKOTA. THAT FRONT WILL MOVE SOUTHEAST INTO NORTHEAST NEBRASKA THIS AFTERNOON. LOOK FOR HIGHS IN THE MID TO UPPER 80S AT MOST SPOTS TODAY WITH A FEW HIGHS AROUND 90 POSSIBLE. THIS WILL CREATE CAPE VALUES FROM 1500 TO 2500 J/KG BY MID AFTERNOON. EXPECT CAP TO BREAK NEAR THE FRONT BY MID/LATE AFTERNOON. SOME MODELS ALSO HINT AT THE CAP WEAKENING FARTHER SOUTH...BUT WITH A LACK OF FOCUS AT THAT TIME WILL KEEP HIGHEST POPS CLOSER TO THE FRONT. SOME SEVERE STORMS APPEAR POSSIBLE...WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. GENERALLY USED A BLEND OF SHORT RANGE GUIDANCE FOR TONIGHT WITH THE HIGHEST WEIGHT GIVEN TO THE 00Z HIGH RES WRF-ARW MODEL. LIKE SOME OF THE OTHER MODELS...IT DEVELOPED STORMS LATE AFTERNOON THEN MOVED THEM SOUTH AND EAST. SOME STORMS MAY CONTINUE TO BE SEVERE IN THE EVENING. COVERAGE SHOULD DECREASE AFTER MIDNIGHT. CONVECTION WILL LIKELY FORCE THE FRONT DOWN AT LEAST AS FAR AS SOUTHEAST NEBRASKA AND MAYBE INTO NORTHEAST KANSAS BY 12Z MONDAY. MOST MODELS SHOW LIFT OCCURRING OVER THE BOUNDARY DURING THE DAY MONDAY WITH PCPN COVERAGE INCREASING...SO HAVE POPS INCREASING TO MATCH THAT. TWO CLUSTERS OF STORMS MAY TAKE SHAPE BY LATE AFTERNOON OR EARLY EVENING. ONE NEAR THE NEBRASKA/SOUTH DAKOTA BORDER AND ANOTHER LIFTING FROM NORTHERN KANSAS THROUGH OUR AREA AND TOWARD CENTRAL IOWA MONDAY NIGHT. TUESDAY...WE MAY SEE SOMEWHAT OF A BREAK IN THE WIDESPREAD PCPN... AT LEAST OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. HAVE POPS RANGING FROM 15 TO 50 PERCENT...HIGHEST IN NORTHEAST NEBRASKA. SOUTHERLY FLOW WILL INCREASE AND HELP A WARM FRONT LIFT NORTH OF THE AREA. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 PATTERN WILL BE ACTIVE MUCH OF THIS PERIOD. A LARGE MID TROPOSPHERIC TROUGH SHOULD BE OVER THE WESTERN UNITED STATES AT THE START OF THIS PERIOD WITH EMBEDDED SHORTWAVES. ONE OF THESE WAVES WILL LIFT ACROSS MID AMERICA WEDNESDAY/WEDNESDAY NIGHT...WHILE A CLOSED LOW STARTS TO DIG SOUTHWARD FROM THE PACIFIC NORTHWEST. THIS WILL GENERALLY KEEP OUR AREA IN SOUTHWEST FLOW WITH A DECENT SUPPLY OF LOW LEVEL MOISTURE FOR SHOWERS AND STORMS TO WORK WITH. MODEL AGREEMENT STARTS TO FALL OFF BY DAY 7...SO CONFIDENCE FALLS TO AVERAGE BY DAY 7. TEMPERATURES AND PCPN SHOULD BE AT OR ABOVE NORMAL FOR THIS PERIOD. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1215 AM CDT SUN MAY 3 2015 LOOK FOR SCT TSRA WILL MOVE EASTWARD AWAY FROM THE TAF SITES THE NEXT FEW HOURS. TSRA SHOULD DEVELOP ALONG A COLD FRONT NEAR KOFK BY MID AFTERNOON THEN MOVE/DEVELOP SOUTHEAST TOWARD KOMA AND KLNK THROUGH THE EVENING. MVFR OR LOWER CEILINGS AND VSBYS WILL BE POSSIBLE IN THE TSRA. OTHERWISE...LOW LEVEL WIND SHEAR EXPECTED EARLY THIS MORNING WITH STRONG LOW LEVEL JET AROUND 1000-3000 FEET AGL. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...PEARSON/MILLER LONG TERM...MILLER AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS ELKO NV
319 PM PDT SUN MAY 3 2015 .SYNOPSIS...WARMER THAN NORMAL CONDITIONS WILL CONTINUE THROUGH TUESDAY...THEN MUCH COOLER FOR THE MIDDLE AND END OF NEXT WEEK COURTESY OF A COOL LOW PRESSURE SYSTEM. THUNDERSTORMS POSSIBLE EACH AFTERNOON...SOME OF THE STORMS WILL PRODUCE STRONG GUSTY WINDS BUT VERY LITTLE IN THE WAY OF RAINFALL. HOWEVER BEGINNING THURSDAY MUCH OF THE AREA WILL HAVE A GOOD SHOT OF WELCOME PRECIPITATION. && .SHORT TERM...TODAY THROUGH WEDNESDAY. RESIDUAL MOISTURE FROM YESTERDAY RESULTING IN MORE INSTABILITY THAN PREVIOUSLY INDICATED. BEST INSTABILITY IS LOCATED IN NORTHERN LANDER/EUREKA AND ELKO COUNTIES. SHEAR IS MINIMAL...WITH MOST AREAS 15 TO 25KTS. THAT IS GOOD ENOUGH FOR SOME MULTICELLUAR STORMS WITH SMALL HAIL AND GUSTY WINDS TO 55 MPH. WOULD NOT BE SHOCKED TO SEE SOME SLIGHTLY HIGHER GUSTS NEAR OR ABOVE 55 MPH...DUE TO FAVORABLE INVERTED V SOUNDINGS AND DRY SUB CLOUD LAYER. JUST EAST INTO UTAH...ALREADY HAD A GUST TO 57 MPH. THE LATEST HRRR MODEL RUNS SHOWS THIS ACTIVITY SHIFTING NORTHWARD/NORTHEASTWARD THROUGH THE EVENING. LIGHTNING WILL DIMINISH AFTER SUNSET...BUT SHOWERS WILL CONTINUE THROUGH THE EVENING. EXPECT MORE OF THE SAME MONDAY AND TUESDAY AS INSTABILITY AND MOISTURE REMAIN. COULD BE A SLIGHT UPTICK IN CONVECTION TOMORROW WITH ADDITIONAL STRONG STORMS POSSIBLE. TUESDAY...CONVECTION WILL FOCUS IN CENTRAL AND EASTERN NEVADA. ON WEDNESDAY...UPPER LEVEL TROUGH STARTS TO DIG INTO NORTHERN NEVADA WITH A COLD FRONT SLOWING/STALLING ACROSS EASTERN NEVADA. WITH INSTABILITY AND FRONTAL DYNAMICS...COULD SEE SOME MODERATE TO HEAVY SHOWERS/STORMS FORM ALONG/BEHIND THAT FRONT IN EASTERN NEVADA. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY. A STRONG UPPER LEVEL TROUGH ACCOMPANIED BY AN UPPER LEVEL JET /H3 100 KT/ WILL DIG SOUTHWARD FROM THE PACIFIC NORTHWEST TO NORTHERN CALIFORNIA WEDNESDAY NIGHT. HAVE INCREASED POPS FOR A SMOOTH TRANSITION FROM THE END OF THE SHORT TERM PERIOD INTO WEDNESDAY NIGHT. THURSDAY...MODELS BRING THE UPPER LEVEL SYSTEM TO NORTH CENTRAL CALIFORNIA DURING THURSDAY. BOTH THE GFS/ECMWF ARE NOW IN FAIRLY GOOD POSITIONAL AGREEMENT. HAVE TRENDED THE POPS UP AS THE ASSOCIATED SURFACE COLD FRONT TRANSITIONS ACROSS NORTHERN AND CENTRAL NEVADA DURING THE DAY. SURFACE WINDS WILL BE BREEZY IN ADVANCE AND ALONG THE SURFACE COLD FRONT ESPECIALLY OVER WHITE PINE AND NORTHEAST NYE COUNTIES. NOT MUCH CHANGE WAS NOTED WITH THE SNOW LEVELS AS THEY WILL REMAIN AROUND 6500-7500 FEET. WITH IS SYSTEM INFLUENCING THE CWA...THE CLOUD COVER...PRECIPITATION AND COLD AIR WILL RESULT IN BELOW NORMAL THURSDAY. THURSDAY NIGHT THROUGH SATURDAY...THE GFS AND ECMWF ARE IN GOOD AGREEMENT MOVING THE UPPER LOW ACROSS SOUTHERN NEVADA AND INTO CENTRAL UTAH THROUGH SATURDAY. WITH THE COLD CORE OF THIS TROUGH MOVING THROUGH THE GREAT BASIN...SCATTERED RAIN AND SNOW SHOWERS WILL BE COMMON ALONG WITH THE POTENTIAL FOR AFTERNOON AND EVENING THUNDER FRIDAY AND SATURDAY AFTERNOON. AFTERNOON MAX TEMPERATURES WILL REMAIN AOB NORMAL LEVELS DURING THIS PERIOD. SUNDAY...AS THE TROUGH SHIFTS INTO THE INTER-MOUNTAIN WEST...A SHORT WAVE RIDGE BUILDS INTO THE GREAT BASIN SUNDAY. MID/HIGH LEVEL CLOUDS WILL BE EVIDENT SPILLING OVER THE RIDGE WHICH WILL HOLD AFTERNOON TEMPERATURES DOWN TO NEAR NORMAL LEVELS. && .AVIATION...CONVECTION HAS FIRED UP BASICALLY ON A FROM LANDER/EUREKA COUNTIES NORTHEASTWARD INTO SOUTHERN AND NORTHEASTERN ELKO COUNTIES. SOME OF THE STRONGER CELLS AND ASSOCIATED OUTFLOWS HAVE PRODUCED SURFACE WIND GUSTS FROM 35 TO 45 MPH. EXPECT THIS TO CONTINUE INTO THIS EVENING BEFORE TRANSITIONING INTO SHOWERS LATER TONIGHT. SIMILAR CONDITIONS ARE EXPECTED AGAIN ON MONDAY. EXPECT VFR CONDITIONS WITH THE POSSIBILITY OF MVFR CONDITIONS NEAR THE CORES OF THE STRONGEST STORMS. .EQUIPMENT...THE WINNEMUCCA ASOS IS EXPERIENCING TELECOMMUNICATIONS ISSUES AT THIS TIME. ALTHOUGH THE ASOS IS NOT TRANSMITTING OBSERVATIONS THROUGH THE INTERNET...LANDLINE COMMUNICATIONS REMAIN OPERATIONAL. IT IS NOT KNOWN AT THIS TIME WHEN THIS WILL BE REPAIRED. && .LKN WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 94/89/89
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
543 AM MDT SUN MAY 3 2015 .AVIATION... 12Z TAF CYCLE ISO-SCT SHRA/TSRA WILL DEVELOP AROUND OR JUST AFTER 18Z TODAY. SIMILAR STORM COVERAGE AS YDAY THOUGH SLIGHTLY MORE WIDESPREAD ACROSS THE EAST. STORM MOTION WILL BE TOWARD THE EAST AROUND 10KTS. BASED ON HRRR OUTPUT...ANY TAF SITE MAY BE IMPACTED... ESPECIALLY WITH GUSTY OUTFLOW WINDS UP TO 40KTS. THE STRONGER STORMS WILL ALSO BE CAPABLE OF PEA SIZE HAIL AND BRIEF MVFR CIGS/VSBYS. STORMS WILL LARGELY DISSIPATE AFTER SUNSET. 34 && .PREV DISCUSSION...335 AM MDT SUN MAY 3 2015... .SYNOPSIS... SLIGHTLY COOLER TODAY WEST AND CENTRAL BUT HIGHS OVERALL REMAINING ABOVE AVERAGE BEFORE FALLING TO BELOW AVERAGE MONDAY THROUGH THURSDAY. ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP AGAIN TODAY OVER THE HIGHER TERRAIN AND TRACK INTO THE VALLEYS AND PLAINS. A SLOW MOVING STORM SYSTEM WILL BRING WIDESPREAD SHOWERS AND STORMS MONDAY THROUGH TUESDAY NIGHT. HEAVY RAIN WILL BE POSSIBLE FROM THE CENTRAL MOUNTAIN CHAIN TO THE TEXAS BORDER...AND POTENTIAL EXISTS FOR A FEW STRONG TO SEVERE THUNDERSTORMS TO DEVELOP BOTH MONDAY AND TUESDAY FROM THE PECOS VALLEY TO THE TEXAS BORDER...MAINLY OVER DE BACA...CHAVES...CURRY AND ROOSEVELT COUNTIES. DRIER AND BREEZY TO WINDY WEATHER IS FORECAST FOR LATE IN THE WEEK. && .DISCUSSION... SPOTTY SHOWERS AND ISOLD STORMS PERSISTING SOUTH OF I-40 EARLY THIS MORNING...AND EXPECTING ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND STORMS TODAY...DEVELOPING OVER THE HIGHER TERRAIN AND MOVING INTO THE LOWER ELEVATIONS THIS AFTERNOON/EVENING. HIGHS CENTRAL AND WEST SLIDE A FEW MORE DEGREES BEFORE COOLING DOWN BELOW AVERAGE OVER THE ENTIRE FORECAST AREA MONDAY AND TUESDAY. A WIDESPREAD PRECIPITATION EVENT IS LOOKING MORE LIKELY FOR NORTHERN AND CENTRAL NM MONDAY THROUGH TUESDAY NIGHT. HEAVY RAIN WILL BE POSSIBLE FOR THE EASTERN PLAINS...WHERE SIGNIFICANT AMOUNTS COULD RESULT IN POTENTIAL FOR AT LEAST LOCALIZED FLOODING...ESPECIALLY ALONG AND EAST OF THE PECOS. COORDINATED WITH MAF ON POSSIBLE FLASH FLOOD WATCH...WILL LEAVE THAT DECISION TO SUCCEEDING SHIFTS...BUT NEW QPF AMOUNTS UPWARDS OF 2 INCHES MONDAY-TUESDAY NIGHT EAST OF THE PECOS. IN ADDITION...SPC DAY 2 AND 3 CONVECTIVE OUTLOOKS PUT THE EASTERN PLAINS IN A MARGINAL AREA...WITH SLIGHT RISK FOR SEVERE STORMS FOCUSED OVER DE BACA...CHAVES...ROOSEVELT AND CURRY COUNTIES BOTH MONDAY AND TUESDAY. GFS IS TRENDING A BIT DRIER EARLIER...TUESDAY NIGHT...THAN IT HAD BEEN...BUT BY WEDNESDAY THE UPPER TROUGH WILL BE EXITING AND THE FOCUS FOR ANY CONVECTION SHOULD BE OVER THE NORTHWEST THIRD AND PERHAPS ALONG THE EASTERN BORDER WITH TX. THEREAFTER...A LARGE AREA OF LOW PRESSURE ALOFT WILL DEVELOP OVER THE GREAT BASIN...BUT NEW MEXICO WILL BE ON THE DRY AND WINDY SIDE OF THE LOW AS IT EJECTS INTO THE CENTRAL ROCKIES OVER THE UPCOMING WEEKEND. A FEW STORMS COULD IGNITE ALONG THE FAR EASTERN PLAINS LATE IN THE WEEK AS LOW LEVEL MOISTURE SLOSHES BACK AND FORTH. && .FIRE WEATHER... STILL LOOKING FOR ANOTHER ROUND OF SHOWERS AND A MIX OF WET AND DRY THUNDERSTORMS THIS AFTERNOON. CONVECTIVE COVERAGE SHOULD BE SIMILAR TO YESTERDAY...WITH PERHAPS SLIGHTLY MORE ACTIVITY ACROSS THE CENTRAL HIGHLANDS AND EAST CENTRAL PLAINS. OTHERWISE...TEMPS ARE EXPECTED TO BE WITHIN 5 DEGREES OF YESTERDAYS READINGS WITH MINIMUM HUMIDITIES GENERALLY ABOVE 15 PERCENT. HUMIDITY RECOVERIES TONIGHT WILL IMPROVE AGAIN OVER THIS MORNINGS READINGS...MAINLY ACROSS THE EAST...AS GULF MOISTURE ADVECTS INTO THE PLAINS. RECOVERIES WILL BE GOOD TO EXCELLENT MOST AREAS. A PACIFIC LOW WILL APPROACH NM ON MONDAY AND CROSS THE STATE ON TUESDAY. THE AFOREMENTIONED GULF MOISTURE PLUS LIFT AND INSTABILITY AHEAD AND BELOW THE UPPER LOW WILL RESULT IN WIDESPREAD SHOWERS AND THUNDERSTORMS. AREAS ACROSS THE EASTERN PLAINS MAY RECEIVE BETWEEN ONE AND THREE INCHES OF RAINFALL. FLOODING IS POSSIBLE...AS WELL AS SOME SEVERE STORMS IN THE AFTERNOON BOTH MONDAY AND TUESDAY. ELSEWHERE...EXPECT STORMS...THOUGH RAINFALL AMOUNTS WILL NOT BE QUITE AS SIGNIFICANT. TEMPERATURES WILL COOL THROUGH THIS PERIOD...WITH ALL AREAS BETWEEN 5 AND 10 DEGREES BELOW NORMAL TUESDAY AFTERNOON. A WARMING AND DRYING TREND WILL FOLLOW ON WEDNESDAY AND THURSDAY AS A DRY SLOT PUNCHES THROUGH THE STATE. HOWEVER...TEMPS WILL BE NEAR TO JUST BELOW NORMAL. STILL LOOKING FOR A FEW SHOWERS ACROSS THE NORTHWEST ON WEDNESDAY...BUT MOST AREAS SHOULD BE DRY ON THURSDAY...THOUGH SOME DRYLINE ACTIVITY IS NOT OUT OF THE QUESTION. A STRONG LEE SIDE TROUGH WILL DEVELOP ON WEDNESDAY...ALLOWING WEST-SOUTHWESTERLY WINDS TO INCREASE ACROSS THE PLAINS. HUMIDITIES WILL STAY ABOVE 15 PERCENT...PLUS THIS AREA IS EXPECTED TO RECEIVE ABUNDANT RAIN ON MON/TUE...SO NO CRITICAL CONDITIONS ARE EXPECTED. WIND SPEEDS WILL TREND UP ON THURSDAY AND FRIDAY...AS THE NEXT STORM SYSTEM DIVES TOWARD THE GREAT BASIN AND LEE SIDE TROUGHING PERSISTS. A STRONGER DRY SLOT WILL ALSO PUNCH IN OVER NM ON FRIDAY. THE STRONGEST WINDS OF THE WEEK MAY ARRIVE NEXT SATURDAY AS THE SYSTEM LIFTS AND SHIFTS EASTWARD ACROSS UTAH AND COLORADO. TEMPS LOOK TO REMAIN NEAR TO BELOW NORMAL THRU THIS PERIOD. VENTILATION VALUES SHOULD BE GOOD OR BETTER THROUGH THE NEXT 7 DAYS. 34 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1251 PM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 1234 PM CDT SUN MAY 3 2015 FORECAST ON TRACK. NO CHANGES NEEDED. UPDATE ISSUED AT 953 AM CDT SUN MAY 3 2015 BASED ON CURRENT RADAR TRENDS AND HIGH RESOLUTION MODEL SOLUTIONS MAINTAINED ISOLD T THROUGH THE REMAINDER OF THE MORNING ACROSS THE FAR SE CORNER OF THE FA. ALSO MENTIONED SOME SPRINKLES VCNTY VALLEY CITY IN ZONE OF WEAKENING FRONTOGENETIC FORCING. ALSO INCREASED CLOUD COVER THIS MORNING ACROSS ALL BUT THE FAR NORTH AND SOUTH. UPDATE ISSUED AT 648 AM CDT SUN MAY 3 2015 SOME DECENT RADAR RETURNS HAVE DEVELOPED OVER CENTRAL ND ALONG THE 700MB FRONTOGENESIS BAND...WITH A LITTLE BIT OF LIGHT RAIN REACHING THE GROUND AT BIS. THE FRONTOGENESIS WILL BEGIN TO MOVE INTO OUR SOUTHERN COUNTIES BY 15Z...BUT THE RAP AND HRRR HAVE LITTLE TO NO QPF. WILL CONTINUE TO KEEP SOME MINIMAL POPS IN THE SOUTH AND EAST THIS MORNING BUT THINK THAT IT SHOULD BE FAIRLY QUIET. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 346 AM CDT SUN MAY 3 2015 WINDS TODAY AND TEMPERATURES THROUGHOUT THE PERIOD WILL BE THE MAIN FORECAST ISSUES FOR THE SHORT TERM. A SHORTWAVE TROUGH MOVING ACROSS SOUTHERN MANITOBA TODAY AND INTO ONTARIO WILL HELP PUSH A WEAK COLD FRONT THROUGH THE CWA. WINDS HAVE ALREADY SHIFTED TO THE NORTH ACROSS THE DEVILS LAKE BASIN AND NORTHERN RED RIVER VALLEY. THINK THAT THE BOUNDARY WILL BE THROUGH THE SOUTHERN AND EASTERN CWA BY THE 15 TO 18Z TIME FRAME. A FEW LINGERING SHOWERS MAINLY OVER THE SOUTHEASTERN COUNTIES WILL BE POSSIBLE...BUT ANY AMOUNTS WILL BE EVEN LIGHTER THAN YESTERDAY. WINDS WILL BE THE MAIN CONCERN THIS AFTERNOON. THERE WILL BE A FAIRLY DECENT PRESSURE GRADIENT WHICH SHOULD MAKE IT SOMEWHAT BREEZY. MIXING UP TO AROUND 800MB OR SO IS LIKELY...BUT WINDS AT THE TOP OF THE MIXED LAYER ARE ONLY AROUND 20 KTS. THINK THAT SOME SUSTAINED WINDS IN THE TEENS WITH GUSTS ABOVE 20 MPH WILL BE POSSIBLE...ENOUGH TO CAUSE SOME FIRE WEATHER HEADACHES. TEMPS SHOULD BE COOLER THAN YESTERDAY BUT STILL PRETTY MILD...RISING INTO THE 60S TO LOW 70S. TONIGHT...SFC HIGH PRESSURE WILL BUILD INTO THE REGION...BRINGING MOSTLY CLEAR SKIES AND LIGHT WINDS. THIS SHOULD ALLOW TEMPS TO FALL INTO THE UPPER 30S TO LOW 40S. MONDAY WILL ALSO BE VERY QUIET UNDER NEAR ZONAL FLOW AS THE SFC HIGH BEGINS TO MOVE EAST. WINDS SHOULD BE SHIFTING TO THE SOUTH BUT WILL REMAIN FAIRLY LIGHT AND THINK THAT HIGHS AGAIN WILL BE IN THE 60S TO LOW 70S. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 346 AM CDT SUN MAY 3 2015 MONDAY NIGHT THROUGH TUESDAY NIGHT...THE MAIN EVENT WILL BE AN UPPER TROUGH MOVING FROM THE DESERT SOUTHWEST THROUGH COLORADO AND OUT INTO THE CENTRAL PLAINS. SFC LOW PRESSURE WILL BEGIN TO DEVELOP TO OUR WEST AND BRING SOME HIGHER MOISTURE LEVELS AS SOUTHERLY WINDS KICK IN. TEMPS SHOULD BE RISING AGAIN WITH MORE HIGHS IN THE 70S FOR TUESDAY. SFC LOW PRESSURE WILL BE MOVING UP INTO WESTERN SD TUESDAY NIGHT...WITH A WARM FRONT PUSHING INTO ND MAINLY AFTER MIDNIGHT. CONTINUED WITH HIGH POPS FOR TUESDAY NIGHT...AND WITH SHOWALTERS NEAR ZERO KEPT MAINLY SHOWERS WITH ISOLATED THUNDER FOR NOW. WEDNESDAY THROUGH SATURDAY...THE LONG TERM MODELS CONTINUE TO LOOK WET FOR THE MIDDLE PART OF THE WORK WEEK...WITH THE GULF OPENING UP ON TUESDAY FOR DECENT MOISTURE FLUX INTO THE CENTRAL AND NORTHERN PLAINS. A SW UPPER FLOW PATTERN SETS UP ON TUESDAY AND PRECIPITATION BEGINS TO LIFT OUT OF THE CENTRAL PLAINS TUE NIGHT INTO WEDNESDAY. A SFC LOW THEN MOVES INTO NE/SD WED INTO THU...KEEPING PRECIP ACROSS ND AND NW MN. MODELS CONTINUE TO HAVE SLIGHT DIFFERENCES IN PLACEMENT AND TIMING OF ANY DRY SLOT WHICH MAY OCCUR AS THE LOW LIFTS INTO NW MN AND ONTARIO...HOWEVER THERE IS A STRONG SIGNAL FOR PRECIPITATION ACROSS THE CWA IN THE WED/THU TIMEFRAME. THIS COULD PROVIDE SOME RELIEF TO THE DRY FIRE WX CONDS WE HAVE HAD OVER THE LAST SEVERAL WEEKS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1245 PM CDT SUN MAY 3 2015 MODERATE NORTHWEST BOUNDARY LAYER WINDS ACROSS THE FA THIS AFTERNOON WILL DIMINISH WITH NIGHTFALL. MID TO UPPER LEVEL CLOUDS ALG AND EAST OF A ROX-RDR-JMS LINE WILL STEADILY SHIFT EASTWARD WITH VFR CONDS PERSISTING THROUGHOUT THE PERIOD. SURFACE HIGH PRESSURE SHOULD BE CENTERED OVER THE RRV EARLY MONDAY MORNING WITH LIGHT AND VARIABLE WINDS AND FAIR SKIES. && .FIRE WEATHER... ISSUED AT 337 AM PM CDT SAT MAY 2 2015 THE LONG TERM MODELS CONTINUE TO LOOK WET FOR THE MIDDLE PART OF THE WORK WEEK...WITH THE GULF OPENING UP ON TUESDAY FOR DECENT MOISTURE FLUX INTO THE CENTRAL AND NORTHERN PLAINS. A SW UPPER FLOW PATTERN SETS UP ON TUESDAY AND PRECIPITATION BEGINS TO LIFT OUT OF THE CENTRAL PLAINS TUE NIGHT INTO WEDNESDAY. A SFC LOW THEN MOVES INTO NE/SD WED INTO THU...KEEPING PRECIP ACROSS ND AND NW MN. MODELS CONTINUE TO HAVE SLIGHT DIFFERENCES IN PLACEMENT AND TIMING OF ANY DRY SLOT WHICH MAY OCCUR AS THE LOW LIFTS INTO NW MN AND ONTARIO...HOWEVER THERE IS A STRONG SIGNAL FOR PRECIPITATION ACROSS THE CWA IN THE WED/THU TIMEFRAME. THIS COULD PROVIDE SOME RELIEF TO THE DRY FIRE WX CONDS WE HAVE HAD OVER THE LAST SEVERAL WEEKS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...JR LONG TERM...JR/SPEICHER AVIATION...GUST FIRE WEATHER...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
957 AM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 953 AM CDT SUN MAY 3 2015 BASED ON CURRENT RADAR TRENDS AND HIGH RESOLUTION MODEL SOLUTIONS MAINTAINED ISOLD T THROUGH THE REMAINDER OF THE MORNING ACROSS THE FAR SE CORNER OF THE FA. ALSO MENTIONED SOME SPRINKLES VCNTY VALLEY CITY IN ZONE OF WEAKENING FRONTOGENETIC FORCING. ALSO INCREASED CLOUD COVER THIS MORNING ACROSS ALL BUT THE FAR NORTH AND SOUTH. UPDATE ISSUED AT 648 AM CDT SUN MAY 3 2015 SOME DECENT RADAR RETURNS HAVE DEVELOPED OVER CENTRAL ND ALONG THE 700MB FRONTOGENESIS BAND...WITH A LITTLE BIT OF LIGHT RAIN REACHING THE GROUND AT BIS. THE FRONTOGENESIS WILL BEGIN TO MOVE INTO OUR SOUTHERN COUNTIES BY 15Z...BUT THE RAP AND HRRR HAVE LITTLE TO NO QPF. WILL CONTINUE TO KEEP SOME MINIMAL POPS IN THE SOUTH AND EAST THIS MORNING BUT THINK THAT IT SHOULD BE FAIRLY QUIET. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 346 AM CDT SUN MAY 3 2015 WINDS TODAY AND TEMPERATURES THROUGHOUT THE PERIOD WILL BE THE MAIN FORECAST ISSUES FOR THE SHORT TERM. A SHORTWAVE TROUGH MOVING ACROSS SOUTHERN MANITOBA TODAY AND INTO ONTARIO WILL HELP PUSH A WEAK COLD FRONT THROUGH THE CWA. WINDS HAVE ALREADY SHIFTED TO THE NORTH ACROSS THE DEVILS LAKE BASIN AND NORTHERN RED RIVER VALLEY. THINK THAT THE BOUNDARY WILL BE THROUGH THE SOUTHERN AND EASTERN CWA BY THE 15 TO 18Z TIME FRAME. A FEW LINGERING SHOWERS MAINLY OVER THE SOUTHEASTERN COUNTIES WILL BE POSSIBLE...BUT ANY AMOUNTS WILL BE EVEN LIGHTER THAN YESTERDAY. WINDS WILL BE THE MAIN CONCERN THIS AFTERNOON. THERE WILL BE A FAIRLY DECENT PRESSURE GRADIENT WHICH SHOULD MAKE IT SOMEWHAT BREEZY. MIXING UP TO AROUND 800MB OR SO IS LIKELY...BUT WINDS AT THE TOP OF THE MIXED LAYER ARE ONLY AROUND 20 KTS. THINK THAT SOME SUSTAINED WINDS IN THE TEENS WITH GUSTS ABOVE 20 MPH WILL BE POSSIBLE...ENOUGH TO CAUSE SOME FIRE WEATHER HEADACHES. TEMPS SHOULD BE COOLER THAN YESTERDAY BUT STILL PRETTY MILD...RISING INTO THE 60S TO LOW 70S. TONIGHT...SFC HIGH PRESSURE WILL BUILD INTO THE REGION...BRINGING MOSTLY CLEAR SKIES AND LIGHT WINDS. THIS SHOULD ALLOW TEMPS TO FALL INTO THE UPPER 30S TO LOW 40S. MONDAY WILL ALSO BE VERY QUIET UNDER NEAR ZONAL FLOW AS THE SFC HIGH BEGINS TO MOVE EAST. WINDS SHOULD BE SHIFTING TO THE SOUTH BUT WILL REMAIN FAIRLY LIGHT AND THINK THAT HIGHS AGAIN WILL BE IN THE 60S TO LOW 70S. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 346 AM CDT SUN MAY 3 2015 MONDAY NIGHT THROUGH TUESDAY NIGHT...THE MAIN EVENT WILL BE AN UPPER TROUGH MOVING FROM THE DESERT SOUTHWEST THROUGH COLORADO AND OUT INTO THE CENTRAL PLAINS. SFC LOW PRESSURE WILL BEGIN TO DEVELOP TO OUR WEST AND BRING SOME HIGHER MOISTURE LEVELS AS SOUTHERLY WINDS KICK IN. TEMPS SHOULD BE RISING AGAIN WITH MORE HIGHS IN THE 70S FOR TUESDAY. SFC LOW PRESSURE WILL BE MOVING UP INTO WESTERN SD TUESDAY NIGHT...WITH A WARM FRONT PUSHING INTO ND MAINLY AFTER MIDNIGHT. CONTINUED WITH HIGH POPS FOR TUESDAY NIGHT...AND WITH SHOWALTERS NEAR ZERO KEPT MAINLY SHOWERS WITH ISOLATED THUNDER FOR NOW. WEDNESDAY THROUGH SATURDAY...THE LONG TERM MODELS CONTINUE TO LOOK WET FOR THE MIDDLE PART OF THE WORK WEEK...WITH THE GULF OPENING UP ON TUESDAY FOR DECENT MOISTURE FLUX INTO THE CENTRAL AND NORTHERN PLAINS. A SW UPPER FLOW PATTERN SETS UP ON TUESDAY AND PRECIPITATION BEGINS TO LIFT OUT OF THE CENTRAL PLAINS TUE NIGHT INTO WEDNESDAY. A SFC LOW THEN MOVES INTO NE/SD WED INTO THU...KEEPING PRECIP ACROSS ND AND NW MN. MODELS CONTINUE TO HAVE SLIGHT DIFFERENCES IN PLACEMENT AND TIMING OF ANY DRY SLOT WHICH MAY OCCUR AS THE LOW LIFTS INTO NW MN AND ONTARIO...HOWEVER THERE IS A STRONG SIGNAL FOR PRECIPITATION ACROSS THE CWA IN THE WED/THU TIMEFRAME. THIS COULD PROVIDE SOME RELIEF TO THE DRY FIRE WX CONDS WE HAVE HAD OVER THE LAST SEVERAL WEEKS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 648 AM CDT SUN MAY 3 2015 VFR CONDITIONS CONTINUE WITH ONLY SOME MID AND HIGH CLOUDS THROUGHOUT THE PERIOD. NORTHWEST WINDS WILL PICK UP TO AROUND 15 KTS SUSTAINED WITH GUSTS ABOVE 20 KTS. WINDS WILL DIMINISH BY THIS EVENING AND STAY UNDER 10 KTS THROUGH SUNDAY NIGHT. && .FIRE WEATHER... ISSUED AT 337 AM PM CDT SAT MAY 2 2015 THE LONG TERM MODELS CONTINUE TO LOOK WET FOR THE MIDDLE PART OF THE WORK WEEK...WITH THE GULF OPENING UP ON TUESDAY FOR DECENT MOISTURE FLUX INTO THE CENTRAL AND NORTHERN PLAINS. A SW UPPER FLOW PATTERN SETS UP ON TUESDAY AND PRECIPITATION BEGINS TO LIFT OUT OF THE CENTRAL PLAINS TUE NIGHT INTO WEDNESDAY. A SFC LOW THEN MOVES INTO NE/SD WED INTO THU...KEEPING PRECIP ACROSS ND AND NW MN. MODELS CONTINUE TO HAVE SLIGHT DIFFERENCES IN PLACEMENT AND TIMING OF ANY DRY SLOT WHICH MAY OCCUR AS THE LOW LIFTS INTO NW MN AND ONTARIO...HOWEVER THERE IS A STRONG SIGNAL FOR PRECIPITATION ACROSS THE CWA IN THE WED/THU TIMEFRAME. THIS COULD PROVIDE SOME RELIEF TO THE DRY FIRE WX CONDS WE HAVE HAD OVER THE LAST SEVERAL WEEKS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...JR LONG TERM...JR/SPEICHER AVIATION...JR FIRE WEATHER...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
648 AM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 648 AM CDT SUN MAY 3 2015 SOME DECENT RADAR RETURNS HAVE DEVELOPED OVER CENTRAL ND ALONG THE 700MB FRONTOGENESIS BAND...WITH A LITTLE BIT OF LIGHT RAIN REACHING THE GROUND AT BIS. THE FRONTOGENESIS WILL BEGIN TO MOVE INTO OUR SOUTHERN COUNTIES BY 15Z...BUT THE RAP AND HRRR HAVE LITTLE TO NO QPF. WILL CONTINUE TO KEEP SOME MINIMAL POPS IN THE SOUTH AND EAST THIS MORNING BUT THINK THAT IT SHOULD BE FAIRLY QUIET. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 346 AM CDT SUN MAY 3 2015 WINDS TODAY AND TEMPERATURES THROUGHOUT THE PERIOD WILL BE THE MAIN FORECAST ISSUES FOR THE SHORT TERM. A SHORTWAVE TROUGH MOVING ACROSS SOUTHERN MANITOBA TODAY AND INTO ONTARIO WILL HELP PUSH A WEAK COLD FRONT THROUGH THE CWA. WINDS HAVE ALREADY SHIFTED TO THE NORTH ACROSS THE DEVILS LAKE BASIN AND NORTHERN RED RIVER VALLEY. THINK THAT THE BOUNDARY WILL BE THROUGH THE SOUTHERN AND EASTERN CWA BY THE 15 TO 18Z TIME FRAME. A FEW LINGERING SHOWERS MAINLY OVER THE SOUTHEASTERN COUNTIES WILL BE POSSIBLE...BUT ANY AMOUNTS WILL BE EVEN LIGHTER THAN YESTERDAY. WINDS WILL BE THE MAIN CONCERN THIS AFTERNOON. THERE WILL BE A FAIRLY DECENT PRESSURE GRADIENT WHICH SHOULD MAKE IT SOMEWHAT BREEZY. MIXING UP TO AROUND 800MB OR SO IS LIKELY...BUT WINDS AT THE TOP OF THE MIXED LAYER ARE ONLY AROUND 20 KTS. THINK THAT SOME SUSTAINED WINDS IN THE TEENS WITH GUSTS ABOVE 20 MPH WILL BE POSSIBLE...ENOUGH TO CAUSE SOME FIRE WEATHER HEADACHES. TEMPS SHOULD BE COOLER THAN YESTERDAY BUT STILL PRETTY MILD...RISING INTO THE 60S TO LOW 70S. TONIGHT...SFC HIGH PRESSURE WILL BUILD INTO THE REGION...BRINGING MOSTLY CLEAR SKIES AND LIGHT WINDS. THIS SHOULD ALLOW TEMPS TO FALL INTO THE UPPER 30S TO LOW 40S. MONDAY WILL ALSO BE VERY QUIET UNDER NEAR ZONAL FLOW AS THE SFC HIGH BEGINS TO MOVE EAST. WINDS SHOULD BE SHIFTING TO THE SOUTH BUT WILL REMAIN FAIRLY LIGHT AND THINK THAT HIGHS AGAIN WILL BE IN THE 60S TO LOW 70S. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 346 AM CDT SUN MAY 3 2015 MONDAY NIGHT THROUGH TUESDAY NIGHT...THE MAIN EVENT WILL BE AN UPPER TROUGH MOVING FROM THE DESERT SOUTHWEST THROUGH COLORADO AND OUT INTO THE CENTRAL PLAINS. SFC LOW PRESSURE WILL BEGIN TO DEVELOP TO OUR WEST AND BRING SOME HIGHER MOISTURE LEVELS AS SOUTHERLY WINDS KICK IN. TEMPS SHOULD BE RISING AGAIN WITH MORE HIGHS IN THE 70S FOR TUESDAY. SFC LOW PRESSURE WILL BE MOVING UP INTO WESTERN SD TUESDAY NIGHT...WITH A WARM FRONT PUSHING INTO ND MAINLY AFTER MIDNIGHT. CONTINUED WITH HIGH POPS FOR TUESDAY NIGHT...AND WITH SHOWALTERS NEAR ZERO KEPT MAINLY SHOWERS WITH ISOLATED THUNDER FOR NOW. WEDNESDAY THROUGH SATURDAY...THE LONG TERM MODELS CONTINUE TO LOOK WET FOR THE MIDDLE PART OF THE WORK WEEK...WITH THE GULF OPENING UP ON TUESDAY FOR DECENT MOISTURE FLUX INTO THE CENTRAL AND NORTHERN PLAINS. A SW UPPER FLOW PATTERN SETS UP ON TUESDAY AND PRECIPITATION BEGINS TO LIFT OUT OF THE CENTRAL PLAINS TUE NIGHT INTO WEDNESDAY. A SFC LOW THEN MOVES INTO NE/SD WED INTO THU...KEEPING PRECIP ACROSS ND AND NW MN. MODELS CONTINUE TO HAVE SLIGHT DIFFERENCES IN PLACEMENT AND TIMING OF ANY DRY SLOT WHICH MAY OCCUR AS THE LOW LIFTS INTO NW MN AND ONTARIO...HOWEVER THERE IS A STRONG SIGNAL FOR PRECIPITATION ACROSS THE CWA IN THE WED/THU TIMEFRAME. THIS COULD PROVIDE SOME RELIEF TO THE DRY FIRE WX CONDS WE HAVE HAD OVER THE LAST SEVERAL WEEKS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 648 AM CDT SUN MAY 3 2015 VFR CONDITIONS CONTINUE WITH ONLY SOME MID AND HIGH CLOUDS THROUGHOUT THE PERIOD. NORTHWEST WINDS WILL PICK UP TO AROUND 15 KTS SUSTAINED WITH GUSTS ABOVE 20 KTS. WINDS WILL DIMINISH BY THIS EVENING AND STAY UNDER 10 KTS THROUGH SUNDAY NIGHT. && .FIRE WEATHER... ISSUED AT 337 AM PM CDT SAT MAY 2 2015 THE LONG TERM MODELS CONTINUE TO LOOK WET FOR THE MIDDLE PART OF THE WORK WEEK...WITH THE GULF OPENING UP ON TUESDAY FOR DECENT MOISTURE FLUX INTO THE CENTRAL AND NORTHERN PLAINS. A SW UPPER FLOW PATTERN SETS UP ON TUESDAY AND PRECIPITATION BEGINS TO LIFT OUT OF THE CENTRAL PLAINS TUE NIGHT INTO WEDNESDAY. A SFC LOW THEN MOVES INTO NE/SD WED INTO THU...KEEPING PRECIP ACROSS ND AND NW MN. MODELS CONTINUE TO HAVE SLIGHT DIFFERENCES IN PLACEMENT AND TIMING OF ANY DRY SLOT WHICH MAY OCCUR AS THE LOW LIFTS INTO NW MN AND ONTARIO...HOWEVER THERE IS A STRONG SIGNAL FOR PRECIPITATION ACROSS THE CWA IN THE WED/THU TIMEFRAME. THIS COULD PROVIDE SOME RELIEF TO THE DRY FIRE WX CONDS WE HAVE HAD OVER THE LAST SEVERAL WEEKS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...JR LONG TERM...JR/SPEICHER AVIATION...JR FIRE WEATHER...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1234 AM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 1234 AM CDT SUN MAY 3 2015 LATEST BOWMAN RADAR CONTINUES TO SHOW AN EXPANDING AREA OF REFLECTIVITY`S IN SOUTHEAST MONTANA AND INTO SOUTHWEST NORTH DAKOTA...WITH MORE ISOLATED ECHOES FARTHER NORTH. THE HRRR COMPOSITE REFLECTIVITY SEEMS TO BE HANDLING THE CURRENT SCENARIO WELL AND HAVE FOLLOWED A BLEND OF THE HRRR AND NAM12. THE NAM12 SHOWS A LAYER OF FRONTOGENESIS/750MB-650MB...INITIATING OVER SOUTHWEST NORTH DAKOTA AND SHIFTING INTO SOUTH CENTRAL THROUGH 12Z SUNDAY. VERTICAL MOTION/MAX OMEGA FIELD OCCURRING ATOP THIS LAYER WILL RESULT IN LOWERING CLOUDS TO BETWEEN 7KFT AND 10KFT OVERNIGHT...SUFFICIENT ENOUGH FOR PRECIPITATION TO REACH THE GROUND. AFTER COLLABORATING WITH OUR NEIGHBORING OFFICES...HAVE EXPANDED POPS OVERNIGHT FARTHER NORTH AND EAST...RANGING BETWEEN ISOLATED AND SCATTERED THROUGH 15Z SUNDAY. WILL LOOK MORE INTO THE FIRE WEATHER FORECAST AND POSSIBLE HEADLINES IN THE NEXT FORECAST. UPDATE ISSUED AT 1003 PM CDT SAT MAY 2 2015 RADAR RETURNS SOUTHEAST AND ACROSS THE WEST. WILL MAINTAIN SLIGHT CHANCE SHOWERS SOUTHEAST THIS EVENING AND SOUTHWEST OVERNIGHT. WHILE NOT MUCH WILL REACH THE GROUND SOUTHWEST LATE TONIGHT...RADAR RETURNS VIA BOWMAN RADAR APPEAR ROBUST ENOUGH FOR AN ISOLATED SHOWER SO WILL KEEP SOME LOW POPS IN 06-12Z. UPDATE ISSUED AT 825 PM CDT SAT MAY 2 2015 RED FLAG WAS ALLOWED TO EXPIRE AT 02Z. NO OTHER UPDATES AT THIS TIME. UPDATE ISSUED AT 658 PM CDT SAT MAY 2 2015 COLD FRONT NEARLY THROUGH THE JAMES RIVER VALLEY...SO HAVE SCALED BACK ON EVENING PRECIPITATION/THUNDER CHANCES A BIT...ENDING ALL POPS OVER MY FAR SOUTHEAST BY 04Z. WINDS SHOULD TAPER OFF QUICKLY BETWEEN NOW AND SUNSET (~01Z)...SO WILL BE ABLE TO EXPIRE THE RED FLAG WARNING AS SCHEDULED BY 02Z. REMAINDER OF THE FORECAST ON TRACK...SO NO MAJOR CHANGES. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 245 PM CDT SAT MAY 2 2015 CURRENT SURFACE ANALYSIS PLACES COLD FRONT PUSHING THROUGH NORTH CENTRAL INTO WESTERN NORTH DAKOTA WHILE SHOWERS AND THUNDERSTORMS FIRE UP NEAR A PRE-FRONTAL TROUGH PUSHING OVER NORTHEAST INTO SOUTH CENTRAL NORTH DAKOTA. UPPER LEVEL ANALYSIS PLACES WEAK SHORT WAVE SLIDING THROUGH WEST/SOUTHWEST FLOW AHEAD OF A LOW AMPLITUDE TROUGH PUSHING TO THE EAST OF THE ROCKIES. FOR THE REST OF THIS AFTERNOON INTO TONIGHT...SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND PUSH TO THE EAST. MOST ACTIVITY SHOULD SLIDE TO THE EAST OF OUR AREA EARLY THIS EVENING PER LATEST HIGH-RES IMAGERY WHICH HAS HAD A RATHER GOOD HANDLE ON THE TIMING OF THE STORMS. THERE REMAINS A LOW SEVERE WIND/HAIL CONCERN GIVEN STEEP MID-LEVEL LAPSE RATES AND DRY LOW LAYERS...THOUGH WITH WEAK FORCING AND MODEST INSTABILITY DO NOT EXPECT THIS TO BECOME WIDESPREAD. ANOTHER WEAK WAVE PUSHES INTO THE SOUTHWEST LATE TONIGHT WHICH MAY BRING A FEW LIGHT SHOWERS. ON SUNDAY...QUIET WEATHER EXPECTED IN THE WAKE OF THE COLD FRONT BRINGING NORTHWEST WINDS AND DRY CONDITIONS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM CDT SAT MAY 2 2015 THE MAIN CONCERN IN THE LONG TERM WILL BE THE ACTIVE WEATHER PATTERN TAKING SHAPE FOR THE MIDDLE AND END OF NEXT WEEK. NEAR TERM MODEL SOLUTIONS SUGGEST A SMALL CHANCE OF SHOWERS IN THE SOUTHWEST PART OF THE STATE SUNDAY NIGHT INTO MONDAY...BUT ANY RAINFALL LOOKS SPOTTY. ATTENTION THEN SHIFTS TO A LARGE TROUGH /H5 LOW WHICH WILL MOVE INTO THE WESTERN UNITED STATES. AHEAD OF THE LOW...AN INITIAL SHORT WAVE WILL EJECT INTO THE CENTRAL AND NORTHERN PLAINS...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY NIGHT THAT CONTINUES THROUGH THURSDAY. A BRIEF H5 RIDGE MOVES INTO THE NORTHERN PLAINS THURSDAY NIGHT AND FRIDAY...HOWEVER THE LARGE TROUGH ACROSS THE WESTERN UNITED STATES LIFTS INTO THE REGION FOR NEXT WEEKEND. IT APPEARS MUCH OF THE AREA COULD RECEIVE MUCH NEEDED RAIN AS WE HEAD INTO THIS MORE ACTIVE PATTERN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1234 AM CDT SUN MAY 3 2015 A VCSH WILL CONTINUE FOR KDIK/KBIS/KJMS UNTIL AROUND 15Z-8Z SUNDAY AS AN ISOLATED TO SCATTERED RAIN SHOWERS MOVE FROM SOUTHEAST MONTANA ACROSS CENTRAL AND SOUTHERN NORTH DAKOTA. DESPITE THE THREAT OF SHOWERS THROUGH SUNDAY MORNING...CIGS/VSBYS WILL REMAIN VFR. AFTER 18Z SUNDAY...EXPECT A CLEARING SKY WHICH WILL CONTINUE THROUGH THE REST OF THE TAF PERIOD. && .FIRE WEATHER... ISSUED AT 825 PM CDT SAT MAY 2 2015 ON SUNDAY...NEAR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED AS MINIMUM RELATIVE HUMIDITY VALUES RANGE AROUND 20 TO 25 PERCENT WHILE NORTHWEST WINDS INCREASE TO AROUND 15 TO 20 MPH. CONDITIONS WILL BE MONITORED TO SEE IF A FIRE WEATHER HEADLINE WILL BE NEEDED. WETTING RAINS ARE EXPECTED OVER THE REGION TOWARDS THE MIDDLE OF NEXT WEEK. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...JJS LONG TERM...CK AVIATION...KS FIRE WEATHER...JJS/NH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1048 AM EDT SUN MAY 3 2015 .SYNOPSIS... HIGH PRESSURE WILL GENERALLY DOMINATE THE REGION THROUGH MUCH OF NEXT WEEK. ISOLATED SHOWERS AND OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON DURING PEAK HEATING OVER THE MOUNTAINS...WITH CHANCES IMPROVING SLIGHT OUT OVER THE PIEDMONT BY THURSDAY AS A WEAK FRONT SLIDES INTO THE REGION. TEMPERATURES WILL RISE TO ABOVE NORMAL LEVELS...WITH HIGHS TOPPING OUT IN THE LOWER TO MID 80S THE LATTER HALF OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM EDT...TEMPERATURES ARE OFF TO A WARM START IN MOST PLACES AS THE EXPECTED HIGH LEVEL STRATOCUMULUS FIELD HAS NOT FILLED IN APPRECIABLY YET. STILL ANTICIPATE SOME INCREASING CLOUD COVER BELOW A MID LEVEL CAP...BUT WARM MORNING THICKNESSES WILL REQUIRE A ONE DEGREE BOOST IN TEMPS IN MOST PLACES. THE LATEST HRRR RUNS CONTINUE TO FEATURE LITTLE MORE THAN ISOLD AIRMASS TYPE SHOWERS...BUT WITH A GENERAL FOCUS ALONG THE ERN SIDE OF THE MTNS IN DEVELOPING LIGHT UPSLOPE. VERY LITTLE CHANGE TO THE POP FORECAST IS EXPECTED...WITH A RELATIVE FORCING MAXIMUM TOWARD 21Z WITH THE PASSING OF AN UPPER SHORTWAVE TO THE N. ANY AFTN/EARLY EVENING SHOWER ACTIVITY WILL WANE QUICKLY WITH SUNSET TONIGHT. ANOTHER ROUND OF HIGH STRATOCUMULUS/LOW ALTOCU TRAPPED UNDER THE INVERSION WILL KEEP SOME MEASURE OF CLOUDS GOING ALL NIGHT. IN ADDITION...THE AIRMASS WILL CONTINUE TO MODIFY WITH RISING MIN TEMPS. && .SHORT TERM /MONDAY THROUGH TUESDAY/... AS OF 230 AM EDT SUNDAY...THE SHORT TERM FCST PERIOD INITIALIZES MONDAY MORNING AMIDST BROAD FLAT H5 SUBTROPICAL RIDGE...WITH A WEAK DISTURBANCE SLIDING THROUGH THE MEAN FLOW ATOP THE SOUTHERN APPS. AT THE SURFACE...HIGH PRESSURE OFF THE CAROLINA COAST WILL CONTINUE TO ALLOW FOR SOUTHERLY WAA ACROSS NORTHEAST GA AND THE WESTERN CAROLINAS. STEEPENING LOW LEVEL LAPSE RATES DUE TO DIURNAL HEATING ALONG WITH ABOVE MENTIONED UPPER IMPULSE WARRANT CHANCE LEVELS POPS ACROSS THE HIGH TERRAIN ON MONDAY WHERE REGION OF BEST INSTABILITY AND LEAST CIN WILL RESIDE. POPS TAPER SHARPLY TO NON MENTIONABLE LEVEL THROUGH THE FOOTHILLS...LEADING TO A DRY FCST FOR THE PIEDMONT AREAS DUE TO PROXIMITY OF THE PARENT SURFACE HIGH. THE PRIMARY UPPER RIDGE AXIS WILL SHIFT OVERHEAD ON TUESDAY WHICH IS EXPECTED TO LIMIT CONVECTION SOMEWHAT...ESPECIALLY OUTSIDE OF THE MTNS. INSTABILITY WILL BE MAXIMIZED OVER THE HIGH TERRAIN...WHICH COMBINED WITH WEAKER LOW LEVEL CIN DUE TO RETREATING PARENT SURFACE HIGH...CONTINUE TO WARRANT CHANCE POPS. AS STATED ABOVE...EXPECTING ANY CAPPING TO HOLD OUTSIDE OF THE HIGH TERRAIN THUS THE FCST REMAINS DRY FOR TUESDAY ACROSS THESE ZONES. ANY HEAVIER SHOWERS/THUNDERSTORMS THAT DO DEVELOP COULD PRODUCE LOCALLY HEAVY RAINFALL AMOUNTS AS STORM MOTIONS WILL LIKELY BE LESS THAN 5-8KTS...ESPECIALLY ON TUESDAY WHEN MID LEVEL FLOW WEAKENS. OTHERWISE...PARTLY CLOUDY SKIES WILL PREVAIL AMIDST LIGHT SOUTHERLY FLOW. TEMPERATURES THROUGH THE PERIOD WILL EXCEED NORMAL LEVELS WITH HIGHS TOPPING OUT IN THE LOWER 80S ON TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 245 AM EDT SUNDAY...THE MEDIUM RANGE FCST PERIOD INITIALIZES WEDNESDAY MORNING WITH LITTLE TO NO CHANGES MADE TO THE PREVIOUS FCST. HIGHLIGHTS OF THE PERIOD CONTINUE TO BE PREVAILING SUBTROPICAL H5 RIDGE OVER EAST/CENTRAL CONUS WHILE SURFACE HIGH PRESSURE REMAINS CENTERED OVER NEW ENGLAND. FURTHER SOUTH OVER THE NORTHERN CARRIBEAN...A MIDLEVEL DISTURBANCE AND ASSOCIATED HYBRID LOW WILL HAVE FORMED AND MIGRATED NORTHWARD OF THE EAST COAST OF FLORIDA. CLOSER TO HOME...BROAD MID/UPPER LEVEL SUBSIDENCE PATTERN IS EXPECTED TO PREVAIL INITIALLY LEADING TO A CAPPED ENVIRONMENT WITH LITTLE IN THE WAY OF TRIGGERING AVAILABLE FOR CONVECTION ACROSS THE PIEDMONT REGIONS. HOWEVER...OVER THE MOUNTAINS MODELS FAVOR INCREASING INSTABILITY WITH ESE UPSLOPING FLOW PRESENT TO AID CAP EROSION ON WEDNESDAY. THUS...SLIGHT/CHANCE LEVEL POPS ARE FEATURED. ON THURSDAY POPS WILL EXPAND FURTHER INTO THE NC/SC PIEDMONT AND NORTHEAST GA AS THE ABOVE MENTIONED HYBRID LOW...AND ITS LOCATION AT THE TIME BECOMES VITAL TO THE FCST. MODEL DISCONTINUITY AS TO ITS LOCATION WOULD PROVIDE VASTLY DIFFERENT OUTCOMES AS IT PERTAINS TO SENSIBLE WX FOR THE REMAINDER OF THE PERIOD. THE GFS HAS THE LOW SETUP APPROX 2-3 HUNDRED MILES OFF THE SC COAST THURSDAY AFTERNOON...WHILE THE ECMWF IS ABOUT THE SAME DISTANCE FURTHER OUT TO SEA. THE GFS SOLUTION WOULD RESULT IN FLOW ON THE WESTERN FLANK OF THE WAVE YIELDING A NORTHERLY COMPONENT OF MOTION...WHICH WOULD AID INTRUSION OF A WEAK BACK DOOR FRONT INTO THE REGION. THE ECMWF ON THE OTHER HAND INDICATES THE SAME BACK DOOR FRONT...ALBEIT WEAKER. IF THE GFS VERIFIED THE FROPA COULD PROVIDE ENOUGH OF A FOCUS FOR CONVECTION TO OCCUR OUTSIDE OF THE MTNS...THEREFORE FOR THE FCST SLIGHT CHANCE POPS ARE MENTIONED. BOTH THE GFS/ECMWF ILLUSTRATE A WESTWARD JAUNT OF THE LOW ON FRIDAY/SATURDAY EFFECTIVELY KEEPING IT JUST OFF THE GA/SC COAST PER THE GFS...AND THE SC/NC COAST PER THE ECMWF. MOISTURE WRAPPING AROUND THE LOW SHOULD STAY JUST TO THE EAST...THEREFORE THE FCST IS DRY FOR PIEDMONT REGIONS ALL THE WHILE FEATURING SLIGHT/CHANCE LEVEL POPS OVER MTNS WHERE DIURNAL CONVECTION IS FAVORED. TEMPERATURES THROUGH THE PERIOD WILL CONTINUE TO MODERATE TO 5-8 DEGREES ABOVE CLIMO. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... AT KCLT AND ELSEWHERE...VFR IS EXPECTED THROUGH THE PERIOD COURTESY OF DRY HIGH PRESSURE. WILL CONTINUE TO SEE SOME HIGH BASED STRATOCU TRAPPED UNDER THE SUBSIDENCE INVERSION...BUT THIS SHOULD NOT BE OPERATIONALLY SIGNIFICANT. EXPECT WINDS TO COME UP FROM THE SSE TO SSW THROUGH EARLY AFTN AS HIGH PRESSURE MOVES OFF THE COAST. WITH HIGH PRESSURE TO THE EAST...SOME MOISTURE RETURN WILL TAKE PLACE FROM THE S. A CU FIELD IS EXPECTED TO DEVELOP FROM MIDDAY ONWARD...THAT WILL PROBABLY RESULT IN A CEILING IN MOST PLACES IN THE AFTERNOON...BUT WITH A CLOUD BASE AT 060 OR HIGHER. THE MODELS ARE MORE SUPPORTIVE/REACTIVE WITH PRECIP OVER THE HIGHER TERRAIN THIS AFTERNOON...SO A VICINITY SHOWER WAS INCLUDED AT KAVL. OUTLOOK...RETURN FLOW MOISTURE WILL SLOWLY REDEVELOP THROUGH MID WEEK...PRODUCING ISOLD TO SCATTERED DIURNAL CONVECTION EACH DAY... MAINLY OVER THE HIGH TERRAIN. CONFIDENCE TABLE... 14-20Z 20-02Z 02-08Z 08-12Z 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...CDG/HG NEAR TERM...HG SHORT TERM...CDG LONG TERM...CDG AVIATION...HG/PM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
324 PM CDT SUN MAY 3 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 323 PM CDT SUN MAY 3 2015 HAVE SEEN SCATTERED SPRINKLES/LIGHT SHOWERS DEVELOP OVER THE WESTERN CWA ALONG ELEVATED BOUNDARY AHEAD OF THE MID LEVEL WAVE. UPDATED GRIDS TO PROGRESS THIS ACTIVITY EASTWARD ACROSS THE AREA THIS AFTERNOON...WITH CONVECTIVE POTENTIAL GRADUALLY INCREASING ACROSS SOUTHEAST HALF OF THE FORECAST AREA AS THE ELEVATED FRONT WORKS INTO MORE UNSTABLE AIR MASS. SURFACE BASED STORMS MAY BE TOUGHER TO COME BY...AS SURFACE CONVERGENCE SOMEWHAT ILL-DEFINED WITH BROAD AREA OF WEAK/VARIABLE FLOW AHEAD OF THE BOUNDARY... LOCATED SOUTH OF KYKN-KFSD-KTKC LINE AT 18Z. ISOLATED SEVERE STILL APPEAR POSSIBLE ACROSS THE SOUTHEAST...WITH RECENT HRRR MODEL RUNS INDICATING A POTENTIAL FOR WIND THREAT ASSOCIATED WITH COLD POOL AHEAD OF ELEVATED STORMS AS THEY TRACK ACROSS EXTREME SOUTHEAST SD/NORTHWEST IA. NOT WHOLLY CONVINCED THIS WILL PAN OUT...BUT DOES NOT SEEM ENTIRELY UNREASONABLE GIVEN HIGHER-BASED STORMS WITH DRIER AIR UNDERCUTTING BEHIND SURFACE BOUNDARY...SO WILL DEFINITELY NEED TO MONITOR THROUGH THE LATE AFTERNOON/EARLY EVENING. OVERALL CONVECTIVE CHANCES SHOULD WANE AFTER 02Z-03Z AS THE WAVE PASSES BY...WITH OVERNIGHT HOURS INTO EARLY MONDAY MORNING EXPECTED TO BE DRY ACROSS THE AREA. INCREASING ISENTROPIC LIFT AHEAD OF BROAD WAVE SHOULD BEGIN TO SPREAD PRECIP BACK INTO SOUTHERN PARTS OF THE AREA MONDAY AFTERNOON...WITH MAIN QUESTION BEING HOW QUICKLY IT EXPANDS TO THE NORTHEAST THE DRY LOW LEVEL EAST-NORTHEAST FLOW FIRMLY IN PLACE. WILL HOLD GENERALLY SOUTHWEST OF KHON-KFSD-KSPW LINE...SUPPORTED BY GREATER MODEL CONSENSUS OF NAM/ECMWF/GEM. MONDAY SHOULD BE A COOLER DAY...WITH THICKER CLOUDS HOLDING TEMPS IN THE 60S THROUGH THE MISSOURI VALLEY...WITH LOWER 70S MORE PREVALENT TO THE NORTHEAST. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 323 PM CDT SUN MAY 3 2015 ON MONDAY NIGHT AND TUESDAY A WARM FRONT BEGINS TO LIFT NORTHWARD THROUGH NEBRASKA...WITH INCREASING MIDLEVEL THETA E ADVECTION ACROSS OUR AREA DURING THE PERIOD. WITH THIS WILL HAVE INCREASING PRECIPITATION CHANCES...ESPECIALLY IN OUR SOUTH AND EAST. INSTABILITY IS NOT ESPECIALLY IMPRESSIVE SO STAYED MAINLY WITH ISOLATED THUNDER...ALTHOUGH IT DOES LOOK TO BE A LITTLE MORE UNSTABLE IN OUR SOUTH ON TUESDAY AFTERNOON. HIGHS ON TUESDAY WILL MAINLY BE UPPER 60S TO LOWER 70S...THOUGH AREAS THROUGH THE LOWER MO RIVER VALLEY MAY APPROACH 80. ON WEDNESDAY A MORE SIGNIFICANT VORT LOBE BEGINS TO LIFT OUT OF THE WESTERN CONUS UPPER LEVEL TROUGH AND INTO THE CENTRAL AND NORTHERN PLAINS. THIS WILL MOSTLY LIKELY BRING MORE SIGNIFICANT PRECIPITATION TO THE AREA FOR LATER ON WEDNESDAY INTO WEDNESDAY NIGHT. WHILE IT WILL BE FAIRLY UNSTABLE ON WEDNESDAY...SHEAR IS RATHER UNIMPRESSIVE...BUT THERE WILL MOST LIKELY BE THUNDERSTORMS AROUND. HIGHS AGAIN WILL BE RUNNING LOWER TO MID 70S. RAIN CHANCES THEN CONTINUE INTO THURSDAY WHEN A SURFACE FRONTAL BOUNDARY SWINGS ACROSS THE AREA AS THE UPPER LEVEL SHORTWAVE PULLS OFF INTO THE WESTERN GREAT LAKES REGION. MAY FINALLY BEGIN TO DRY OUT BY THURSDAY NIGHT AND FRIDAY AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE REGION BEHIND THE EXITING SYSTEM. SLIGHTLY COOLER AIR FILTERS INTO THE AREA FOR FRIDAY...THOUGH STILL LOOKING AT HIGHS MID 60S TO LOWER 70S. RAIN DOES LOOK TO RETURN BY NEXT WEEKEND HOWEVER AS ANOTHER UPPER LEVEL LOW LIFTS OUT OF THE WESTERN CONUS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 147 PM CDT SUN MAY 3 2015 CONVECTIVE CHANCES THROUGH THE AFTERNOON/EARLY EVENING...ALONG WITH GUSTY POST-FRONTAL SURFACE WINDS...ARE PRIMARY CONCERNS FOR THIS TAF PERIOD. CONVECTIVE THREAT SOMEWHAT ILL-DEFINED AS COOL FRONT WORKS THROUGH MODERATELY UNSTABLE AIR MASS IN NORTHWEST IOWA THIS AFTERNOON. SCATTERED THUNDERSTORMS STILL APPEAR POSSIBLE IN AREAS SOUTH/EAST OF KFSD AND WILL MAINTAIN DRY FORECAST FOR KFSD AS THIS POINT...THOUGH POTENTIAL FOR ISOLATED ELEVATED SHRA/TSRA FOR AN HOUR OR TWO IN THE LATE AFTERNOON. GREATER CHANCE FOR THE KSUX AREA IN THE EARLY EVENING AS ELEVATED FRONT WORKS THROUGH THE AREA. LATE AFTERNOON/EVENING THUNDERSTORM ACTIVITY COULD PRODUCE VARIABLE GUSTY WINDS...POSSIBLY IN EXCESS OF 40KT...THOUGH LOWER CONFIDENCE IN TIMING/LOCATION OF WIND THREAT PRECLUDES MENTION IN TAFS AT THIS TIME. POST-FRONTAL WINDS GUSTING 20-30KT MORE WIDESPREAD AND EXPECTED TO PERSIST INTO THE EVENING BEFORE DIMINISHING AFTER DARK. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JH LONG TERM...JM AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
147 PM CDT SUN MAY 3 2015 .UPDATE... ISSUED AT 147 PM CDT SUN MAY 3 2015 HAVE SEEN SCATTERED SPRINKLES/LIGHT SHOWERS DEVELOP OVER THE WESTERN CWA ALONG ELEVATED BOUNDARY AHEAD OF THE MID LEVEL WAVE. UPDATED GRIDS TO PROGRESS THIS ACTIVITY EASTWARD ACROSS THE AREA THIS AFTERNOON...WITH CONVECTIVE POTENTIAL GRADUALLY INCREASING ACROSS SOUTHEAST HALF OF THE FORECAST AREA AS THE ELEVATED FRONT WORKS INTO MORE UNSTABLE AIR MASS. SURFACE BASED STORMS MAY BE TOUGHER TO COME BY...AS SURFACE CONVERGENCE SOMEWHAT ILL-DEFINED WITH BROAD AREA OF WEAK/VARIABLE FLOW AHEAD OF THE BOUNDARY... LOCATED SOUTH OF KYKN-KFSD-KTKC LINE AT 18Z. ISOLATED SEVERE STILL APPEAR POSSIBLE ACROSS THE SOUTHEAST...WITH RECENT HRRR MODEL RUNS INDICATING A GREATER POTENTIAL FOR WIND THREAT ASSOCIATED WITH EXPANDING COLD POOL AHEAD OF ELEVATED STORMS AS THEY TRACK ACROSS EXTREME SOUTHEAST SD/NORTHWEST IA. OTHERWISE FORECAST APPEARS FAIRLY WELL ON TRACK. POST-FRONTAL WINDS BECAME STRONGER THAN ANTICIPATED WITH INITIAL DEEPER MIXING ACROSS NORTHWEST PARTS OF THE CWA IN THE LATE MORNING...BUT SEEM TO HAVE TAMED DOWN CLOSER TO EXPECTED RANGES NOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 358 AM CDT SUN MAY 3 2015 CONCERNS THIS TODAY AND TONIGHT DEAL WITH CONVECTION CHANCES THIS AFTERNOON ALONG WITH POST FRONTAL FIRE DANGER. EARLY THIS MORNING...LOW LVL JET CONTINUES TO VEER AND PUSH CONVECTION EASTWARD AND AWAY FROM THE CWA INTO CENTRAL IOWA. THERE REMAINS AN OUTSIDE CHANCE FOR A FEW SHOWERS TO POPUP OVER THE EASTERN ZONES...BUT LOOKING LESS LIKELY. THE MAIN STORY TODAY WILL BE FOCUSED ON A FRONTAL BOUNDARY DROPPING SOUTHEAST THROUGH THE AREA THIS EVENING. EARLY THIS MORNING...THE FRONT WAS DRAPED ACROSS CENTRAL SOUTH DAKOTA...ALLOWING LOW TO MID 50 DEW POINTS TO POOL AHEAD OF IT. THIS FRONT WILL SLOWLY PRESS SOUTHEAST STRETCHING FROM WORTHINGTON TO YANKTON BY 4PM. MODELS CONTINUE TO SHOW MODEST DESTABILIZATION THROUGH THE DAY...WITH UPWARDS OF 1500-2000 J/KG MLCAPE VALUES DEVELOPING ALONG AND BEHIND THE BOUNDARY BY LATE AFTERNOON. THERE WILL LIKELY BE TWO MAIN FORCING MECHANISMS THIS AFTERNOON...INCREASING FRONTAL CONVERGENCE LATE THIS AFTERNOON ACROSS THE NORTHEASTERN HALF OF THE FRONT IN MN...AND A SHORTWAVE ROTATING ACROSS NEBRASKA. WHILE DIFFICULT TO PICKUP IN WV IMAGERY...THIS SHORTWAVE WAS BEGINNING TO ENTER THE WESTERN PLAINS EARLY THIS MORNING...EVIDENT BY VEERING NPN/VWP. THE DIFFICULTY THUS FAR...IS ASSESSING THE STRENGTH OF THIS SHORTWAVE...WHICH MODELS HAVE BEEN STRUGGLING WITH. SOUNDINGS INDICATE A RELATIVELY CAPPED ENVIRONMENT...WHICH SHOULD HOLD OFF SFC BASED CONVECTION UNTIL MID-LATE AFTERNOON...WHEN CONVERGENCE ALONG THE BOUNDARY OVER CENTRAL MN SHOULD BE SUFFICIENT. LATEST GUIDANCE SUGGESTS THIS BOUNDARY MAY SURGE A BIT FASTER OVER NORTHERN AND CENTRAL MINNESOTA WITH RATHER HIGH PRESSURE RISES ACROSS THE WESTERN DAKOTAS. THIS IN RETURN COULD LIMIT THE CONVECTIVE POTENTIAL OVER OUR SW MN COUNTIES. HOWEVER...FURTHER SOUTHWEST ALONG THE LINE...INTO FAR SE SD...NW IA...AND NE...INITIAL ISOLATED CONVECTION MAY BE MORE POST FRONTAL AND ELEVATED IN NATURE...DEVELOPING ALONG A SECONDARY 925:850 CONVERGENCE ZONE. MORE ISOLATED TO PERHAPS SCATTERED SFC BASED CONVECTION COULD DEVELOP ONCE FORCING ALOFT CATCHES UP TO THE SFC FRONT TOWARD 00Z. AT THIS POINT...FORCING ASSOCIATED WITH THE SHORTWAVE MAY BE THE MORE DOMINATE FOCUS FOR CONVECTION AS OPPOSED TO THE FRONT...WITH THE BEST CHANCES FOR THUNDER ALONG A YANKTON TO SPENCER LINE. THAT SAID...WOULD NOT BE SURPRISED IF CONVECTION IS JUST NOT THAT WIDESPREAD. AGAIN...INSTABILITY IS MODERATE...BUT SHEAR PROFILE SEEMS MARGINAL FOR THE EVENT. BEST SHEAR IS ACTUALLY IN THE POST FRONTAL ENVIRONMENT. THAT SAID...WOULD ANTICIPATE FAIRLY ISOLATED TO AT MOST SCATTERED CONVECTION...WITH ISOLATED SVR STORMS. RELATIVELY STEEP LAPSE RATES...AND POCKET OF MID-LVL DRY AIR WOULD SUPPORT DAMAGING WIND THREAT. CAPE PROFILE FAIRLY ELONGATED...BUT SKINNY IN NATURE. WITH THE RELATIVELY LOW SHEAR ENVIRONMENT...LOOKING AT A MARGINAL HAIL THREAT. TORNADIC THREAT APPEARS LOW...GIVEN POOR 0-1KM SHEAR...AND RATHER HIGH LCLS. THE SHORTWAVE WILL MOVE QUICKLY EASTWARD IN THE EVENING...WITH CONVECTION PUSHING THE ELEVATED MOISTURE LAYER SOUTH OF THE CWA. DEPENDING ON THE CLEARING...LOOKING AT LOWS IN THE 40S. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 358 AM CDT SUN MAY 3 2015 WHILE STRONGER RIDGING WILL ATTEMPT TO BECOME REESTABLISHED ACROSS THE NORTHERN PLAINS ON MONDAY...WILL HAVE TO DEAL WITH LIFT ASSOCIATED WITH EXITING UPPER JET ENTRANCE REGION PULLING ACROSS THE AREA MONDAY INTO MONDAY EVENING. THE MORNING HOURS WILL SEE MAIN BOUNDARY AT LOWER LEVELS CONTINUING THE PUSH TO AREAS BETWEEN I-80 AND I-70...WITH FAIRLY STRONG PUSH OF LOWER LEVEL DRY AIR THROUGH MUCH OF THE CWA. MID LEVEL MOISTURE SHOULD STALL ACROSS THE AREA... BUT NO MORE THAN A MINIMAL THREAT OF A MID BASED SHOWER ALONG THE EXTREME SOUTHERN BORDER THROUGH THE MORNING. INSTABILITY DISPLACED WELL SOUTHWARD TO PRECLUDE ANY THUNDER MENTION...BUT THIS SHOULD START TO CHANGE DURING THE AFTERNOON AS STRONGER UPPER FORCING WILL COMBINE WITH INCREASE IN ISENTROPIC LIFT TO BULGE PRECIPITATION BACK NORTHWARD THROUGH THE MISSOURI RIVER CORRIDOR ALONG WITH WEAK ELEVATED INSTABILITY FOR AN ISOLATED THUNDER MENTION. GOING THROUGH MONDAY NIGHT AND TUESDAY...LARGER SCALE BROAD ISENTROPIC LIFT WILL SPREAD GRADUALLY NORTHWARD TO THE NORTH OF STRONG SURFACE WARM FRONT LIFTING GRADUALLY NORTH OF I-80. MOST SOLUTIONS DO SUGGEST THAT MAY SEE A MIDDAY MINIMA IN QG SUPPORT FOR PRECIP WITH RIDGING STRENGTHENING ALOFT TO EAST...AND AHEAD OF NEXT LOBE EJECTING FROM SOUTHERN ROCKIES CLOSED LOW PUSHING TOWARD WESTERN CWA. HOWEVER...WITH PERSISTENT ISENTROPIC LIFT...EXPECT AT LEAST A SCATTERING OF SHOWERS TO BE PRESENT. INSTABILITY IS JUST TO THE WEAK SIDE OF NEUTRAL...SO THUNDER WILL BE FAR FROM PREDOMINANT IN COVERAGE...AND HAVE GENERALLY KEPT A CATEGORY OR TWO BELOW ANY PRECIP MENTION. ON TUESDAY NIGHT...COULD ACTUALLY SEE A DECREASE IN COVERAGE OF PRECIP CYCLING NORTHWARD THROUGH THE EASTERN CWA...WITH MAIN ISENTROPIC BAND LIFTING NORTH OF THE CWA...AND LULL AHEAD OF MOISTURE CONVEYOR LOBE WHICH WILL WRAP RAPIDLY NORTH AND EASTWARD TOWARD THE MISSOURI VALLEY BY LATE NIGHT. THE MAIN DYNAMIC FORCING WILL SWING NORTHEASTWARD LATER WEDNESDAY AND WEDNESDAY NIGHT AS UPPER LOW LIFTS FROM COLORADO THROUGH THE DAKOTAS...AND SHOULD FOCUS PERIOD OF MOST SIGNIFICANT RAINFALL ACROSS THE AREA. INSTABILITY JUST A BIT STRONGER...BUT DEEP LAYER SHEAR IS QUITE MINIMAL...SO PROSPECT OF SEVERE STORMS MINIMAL WITH WAVE OUT OF PHASE WITH DIURNAL CYCLE AS WELL. THURSDAY WILL SEE THE LOW LEVEL BOUNDARY PUSHING EASTWARD ACROSS THE CWA AS UPPER LOW LIFTS NORTH OF THE REGION. DEPENDING ON TIMING OF BOUNDARY...DEGREE OF POTENTIAL WARMING AHEAD...MAY SEE SEVERE PARAMETERS FALL OUT A BIT STRONGER NEAR FRONTAL ZONE. MUCH OF THE TUESDAY TO THURSDAY PERIOD WILL HAVE QUITE A BIT OF CLOUDINESS AND MOISTURE...WITH LOWER DIURNAL RANGE. STILL SHOULD SEE TEMPS AT OR ABOVE NORMAL WITH UPPER 60S TO MID 70S COMMON FOR HIGHS...AND 50S TO AROUND 60 FOR LOWS. THE END OF THE LONGER RANGE FOR THURSDAY THROUGH SATURDAY CONTINUES TO ADVERTISE SOME SIGNIFICANT DIFFERENCES IN DETAILS...WHILE A LARGER SCALE AGREEMENT OF WESTERN TROUGHING TO EASTERN PLAINS RIDGING REMAINS IN PLAY. ECMWF/CANADIAN SUGGEST A BIT MORE SOUTHWARD AND QUICKER PUSH TO BAROCLINIC ZONE BY THURSDAY NIGHT AND FRIDAY RESULTING IN A DRIER PERIOD PERHAPS LASTING INTO SATURDAY...AND WOULD NOT BE SURPRISED TO HAVE THINGS SHAKE OUT IN THAT MANNER. ANOTHER FAIRLY STRONG LOBE WILL BE MOVING IN JUST BEYOND THE END OF THE FORECAST PERIOD...AND MAY HAVE SOMEWHAT SLIGHTLY BETTER SHEAR AND INSTABILITY AT HAND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 147 PM CDT SUN MAY 3 2015 CONVECTIVE CHANCES THROUGH THE AFTERNOON/EARLY EVENING...ALONG WITH GUSTY POST-FRONTAL SURFACE WINDS...ARE PRIMARY CONCERNS FOR THIS TAF PERIOD. CONVECTIVE THREAT SOMEWHAT ILL-DEFINED AS COOL FRONT WORKS THROUGH MODERATELY UNSTABLE AIR MASS IN NORTHWEST IOWA THIS AFTERNOON. SCATTERED THUNDERSTORMS STILL APPEAR POSSIBLE IN AREAS SOUTH/EAST OF KFSD AND WILL MAINTAIN DRY FORECAST FOR KFSD AS THIS POINT...THOUGH POTENTIAL FOR ISOLATED ELEVATED SHRA/TSRA FOR AN HOUR OR TWO IN THE LATE AFTERNOON. GREATER CHANCE FOR THE KSUX AREA IN THE EARLY EVENING AS ELEVATED FRONT WORKS THROUGH THE AREA. LATE AFTERNOON/EVENING THUNDERSTORM ACTIVITY COULD PRODUCE VARIABLE GUSTY WINDS...POSSIBLY IN EXCESS OF 40KT...THOUGH LOWER CONFIDENCE IN TIMING/LOCATION OF WIND THREAT PRECLUDES MENTION IN TAFS AT THIS TIME. POST-FRONTAL WINDS GUSTING 20-30KT MORE WIDESPREAD AND EXPECTED TO PERSIST INTO THE EVENING BEFORE DIMINISHING AFTER DARK. && .FIRE WEATHER... ISSUED AT 358 AM CDT SUN MAY 3 2015 HIGH TO VERY HIGH FIRE DANGER EXPECTED TODAY...PRIMARILY ALONG AND WEST OF A MARSHALL TO YANKTON LINE. THE DRIVING FORCE BEHIND TODAYS HIGH FIRE DANGER WILL BE STRONG POST FRONTAL WINDS UP TO 20 KNOTS AT TIMES. THE AIR IMMEDIATELY BEHIND THE INCOMING FRONTAL BOUNDARY WILL NOT BE ALL THAT DRY...SO RH VALUES WILL ONLY FALL TO AROUND 25 TO 30 PERCENT. THUS...NOT ANTICIPATING RED FLAG WARNING CONDITIONS BUT ANY BURNING SHOULD BE DONE WITH CAUTION. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...JH SHORT TERM...DUX LONG TERM...CHAPMAN AVIATION...JH FIRE WEATHER...DUX
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
836 PM CDT Mon May 4 2015 .UPDATE... Convection continues to the west of the CWA. One batch of storms is lifting slowly northeast across the South Plains from Lamesa to near Snyder. A few showers and thunderstorms extend to the south and southeast from this complex, generally along and north of the Colorado River. Farther south, a persistent, right-moving supercell continues to parallel I-10 near Ft. Stockton, with additional development to its west. Given the proximity of this storm to Crockett County, a Tornado Watch was issued through 2 AM. Surface based instability is a bit more limited east of the Pecos River, so the thinking is that this storm should weaken as it moves into Crockett County. However, the HRRR has shown a tendency for additional development in the Big Bend area overnight. There is also the potential for additional thunderstorms to move into the Big Country and Concho Valley late tonight and early Tuesday. If this occurs, it may limit the severe weather potential for tomorrow afternoon/evening. Will have to wait and see how this plays out. Johnson && .PREV DISCUSSION... /ISSUED 629 PM CDT MON MAY 4 2015/ AVIATION... /00Z TAFS/ Flight conditions will deteriorate at all terminals through the next 24 hours. Ceilings will drop into the 1500 to 2500 feet range after 04z at all TAF sites, with southern terminals dropping to around 800 feet after 08z. Southeast winds gusting over 20 knots are likely area- wide tonight, with these gusts increasing to near 30 knots tomorrow afternoon across the northern terminals, and near/over 20 knots farther south. Showers and thunderstorms may develop at any time during the TAF cycle. For now, have inserted VCTS at KABI and KSJT for the next couple of hours based on radar trends.. PREV DISCUSSION... /ISSUED 353 PM CDT Mon May 4 2015/ SHORT TERM... (Tonight-Tuesday Night) The main weather concerns for the short term will be the isolated threat of severe thunderstorms this afternoon and a little more widespread threat for severe weather Tuesday. Thunderstorms have already developed this afternoon across much of west central Texas. So far, storms have been of the single cell pulse variety and staying below severe levels. We may see an isolated storm or two produce severe hail this afternoon/evening. However, the bigger threat for severe weather today will be farther west over the Permian Basin. We may see a few storms cross into our western counties this evening...so have kept precipitation chances going overnight. For tomorrow...an upper trough over eastern New Mexico will head northeast across west Texas as the dryline heads east toward our area. Increased cloud cover may limit instability slightly. However, with decent shear across the area, expect more organized convection to develop tomorrow afternoon with a slightly higher threat for severe weather. Think the best chance for severe storms will be across the northern and western parts of the area. Storms should continue into the evening hours. LONG TERM... (Wednesday-Monday) Unsettled weather will continue through the majority of the extended period, with showers and thunderstorms possible through next weekend. The short-wave trough will lift northeast of the area on Wednesday, while another significant upper trough develops across the western states. We`ll remain in southwest flow aloft ahead of this system through Friday, with periodic disturbances moving across the area. The dryline will remain west of the area on Wednesday but will mix east into far western counties Thursday and Friday. Showers and thunderstorms are expected to develop just about anywhere on Wednesday due to a weaker CAP, with a few strong to severe storms possible during the late afternoon and evening hours. Scattered strong to severe thunderstorms will remain a possibility Thursday and Friday ahead of the upper trough to our west, with a continued chance for severe storms next weekend as the upper trough moves across the Plains. && .PRELIMINARY POINT TEMPS/POPS... Abilene 62 74 64 80 66 / 30 50 60 40 40 San Angelo 63 76 65 82 66 / 30 30 40 30 30 Junction 64 77 66 80 67 / 20 40 40 40 30 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 25
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
826 PM CDT MON MAY 4 2015 .UPDATE... /UPDATE FOR NEW TOR WATCH VAL VERDE COUNTY/ ISOLATED SEVERE STORMS WILL CONTINUE TO BE A THREAT FOR VAL VERDE COUNTY. RECENT CELL TRENDS ARE ON THE WAY DOWN OVER SOUTHERN TERRELL COUNTY...BUT THE PAST FEW RUNS OF THE HRRR AND THE TX TECH WRF STILL SUGGEST REGENERATION AND A FAVORABLE SHEAR ENVIRONMENT FOR AN ISOLATED SUPERCELL OR TWO TOWARD MIDNIGHT. THE REST OF THE FORECAST LOOKS IN GOOD SHAPE. && .PREV DISCUSSION... /ISSUED 651 PM CDT MON MAY 4 2015/ UPDATE...UPDATE FOR 00Z AVIATION BELOW. AVIATION...VFR CONDITIONS ONGOING EARLY THIS EVENING ACROSS SOUTH-CENTRAL TEXAS. ISOLATED SHRAS CONTINUE ACROSS VAL VERDE COUNTY...NEAR DRT. STRONGER TSTMS TO THE NORTHWEST MAY MOVE EAST INTO NORTHERN VAL VERDE COUNTY THORUGH THE EVENING. WILL MONITOR RADAR TRENDS...AND SHOULD TSTMS TREND FURTHER SOUTH MAY HAVE TO AMEND TO INCLUDE MENTION AT DRT. OTHERWISE...MOIST LOW LEVEL SOUTH TO SOUTHEAST FLOW WILL CONTINUE...LEADING TO MVFR CEILINGS RE-DEVELOPING 03-06Z AND IFR CEILINGS 07-10Z. CEILINGS FORECAST TO RISE BACK INTO MVFR RANGE 14-16Z...POTENTIALLY VFR MID AFTERNOON ON TUE. SE WINDS AROUND 15 KTS THIS EVENING DIMINISHING TO AROUND 10 KTS AT SAT/SSF/AUS OVERNIGHT. PREV DISCUSSION... /ISSUED 239 PM CDT MON MAY 4 2015/ SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)... UPPER AIR ANALYSIS THIS MORNING SHOWED A RIDGE EXTENDING FROM THE CENTRAL GULF COAST TO THE CENTRAL PLAINS...A TROUGH OVER THE WEST COAST AND SPLIT FLOW DEVELOPING OVER WEST TEXAS. THE 250MB JET EXTENDED FROM THE BOTTOM OF THE WEST COAST TROUGH CURVING ANTICYCLONICALLY ACROSS NORTHERN MEXICO THROUGH WEST TEXAS DOWN TOWARD SOUTH PADRE ISLAND. AT THE SURFACE...HIGH PRESSURE WAS CENTERED TO THE EAST AND WINDS WERE FROM THE SOUTHEAST. LOW LEVEL MOISTURE HAS INCREASED OVER THE LAST 24 HOURS WITH DEW POINT TEMPERATURES 3 TO 10 DEGREES HIGHER. THE LARGER INCREASES ARE ACROSS THE NORTH. DURING THIS PERIOD THE WEST COAST UPPER TROUGH WILL RIDE UP OVER THE RIDGE TO THE CENTRAL PLAINS. THIS WILL BRING SOUTHWESTERLY FLOW OVER TEXAS...BUT IT WILL WEAKEN AS THE TROUGH MOVES TO THE NORTHEAST. CHANCES FOR THUNDERSTORMS WILL MOVE INTO THE REGION FROM THE WEST TONIGHT AND SPREAD ACROSS THE AREA TUESDAY. POPS WILL BE LOW END CHANCE. STORMS ARE LIKELY TO INITIATE ALONG THE DRYLINE OUT WEST. CAPE WILL BE SUFFICIENT TO PRODUCE STRONG TO SEVERE STORMS OUT WEST AND SPC HAS OUR WESTERN AREAS IN THE MARGINAL TO SLIGHT RISK FOR TUESDAY. DEEP LAYER SHEAR MAY BE SUFFICIENT TO SUPPORT A FEW SUPERCELLS. LONG TERM (WEDNESDAY THROUGH MONDAY)... THE UPPER LEVEL PATTERN WILL BE SOMEWHAT STATIC THROUGH THE MIDDLE OF THE WEEK AS A LARGE AMPLITUDE RIDGE AND TROUGH DEVELOP...THE RIDGE IN THE EAST AND THE TROUGH IN THE WEST. THIS WILL KEEP SOUTHWESTERLY FLOW OVER TEXAS. THIS WILL LEAD TO AN EXTENDED PERIOD OF SLIGHT TO LOW END CHANCE POPS WEDNESDAY THROUGH FRIDAY. THE UPPER PATTERN WILL BECOME SLOWLY PROGRESSIVE OVER THE WEEKEND AS THE WESTERN TROUGH MOVES TOWARD THE MIDDLE OF THE COUNTRY. MODELS ARE IN GOOD AGREEMENT ON THE TROUGH MOVING ACROSS TEXAS SUNDAY NIGHT AND MONDAY. THIS WILL BRING HIGHER RAIN CHANCES FOR THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 65 82 69 84 70 / 10 30 40 40 20 AUSTIN BERGSTROM INTL AIRPORT 63 82 68 83 69 / 10 30 40 30 20 NEW BRAUNFELS MUNI AIRPORT 64 82 68 84 70 / 10 30 30 30 20 BURNET MUNI AIRPORT 63 80 67 82 68 / 10 40 40 30 30 DEL RIO INTL AIRPORT 68 81 70 84 70 / 40 40 30 30 30 GEORGETOWN MUNI AIRPORT 63 81 68 82 69 / 10 40 50 40 30 HONDO MUNI AIRPORT 66 81 69 84 70 / 20 30 30 30 30 SAN MARCOS MUNI AIRPORT 64 81 69 82 69 / 10 30 40 30 20 LA GRANGE - FAYETTE REGIONAL 62 82 69 84 71 / 10 30 30 30 20 SAN ANTONIO INTL AIRPORT 66 82 69 84 70 / 10 30 30 30 20 STINSON MUNI AIRPORT 67 83 70 85 71 / 10 20 30 30 20 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...76 SYNOPTIC/GRIDS...18 PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
322 PM MDT SUN MAY 3 2015 .SYNOPSIS... AFTER THREE DAYS OF VERY WARM TEMPERATURES...THE BORDERLAND WILL SEE A COOLER STRETCH OF WEATHER AS A SERIES OF UPPER LOWS TRACK ACROSS THE SOUTHERN U.S. MOISTURE AND INSTABILITY WILL CONTINUE TONIGHT AND MONDAY...ALLOWING ISOLATED THUNDERSTORMS THROUGH MONDAY NIGHT. LOW LEVEL MOISTURE BEGINS DECREASING TUESDAY...THOUGH A SLIGHT CHANCE OF THUNDERSTORMS WILL CONTINUE EAST OF EL PASO. WEDNESDAY THROUGH SATURDAY SHOULD SEE PLENTY OF SUNSHINE...WITH HIGHS REMAINING NEAR NORMAL. && .DISCUSSION... LOOKS LIKE WE ARE ENTERING A COOLER PHASE OF WEATHER THOUGH NOT MUCH WETTER. WV IMAGERY SHOWING DEEPER LAYERED MOISTURE NOW OFF TO OUR EAST AS LARGE DRY SLOT WITH PW`S OF AROUND .4 TO .6 INCHES MOVES OVER THE AREA. HOWEVER IMAGERY DOES APPEAR TO SHOW SEVERAL WEAK DISTURBANCES TRACKING ACROSS THE BAJA TO FAR SOUTHERN ARIZONA AND SOUTHERN NEW MEXICO...ASSOCIATED WITH STRONG 130 KT JET. THE COMBINATION OF THE MODERATE MOISTURE AND DISTURBANCES SHOULD BE ENOUGH TO CONTINUE ISOLATED SHOWERS/THUNDERSTORMS TONIGHT AND MONDAY ACROSS THE CWA. VISIBLE SATELLITE SHOWS CONSIDERABLE CU GROWTH WITH NICE AMOUNT OF TCU/CB. LIGHTNING LOOKS TO BE LIMITED TO MOSTLY DEMING WEST AND ALSO OVER HUDSPETH CO AT THIS TIME. EXPECT THESE ISOLATED TSTMS TO CONTINUE MONDAY...PERHAPS BECOMING SCATTERED OVER THE MOUNTAINS. HRRR SHOWING DCAPES OF 700-900 J/KG...COMBINED WITH DEW POINT DEPRESSIONS OF 50-55 DEG...WILL GIVE SOME WIND GUST POTENTIAL OF 45 TO 55 MPH NEAR ANY SHOWERS TONIGHT. LARGE DEPRESSIONS SHOULD LIMIT ANY RAINFALL AMOUNTS TO QUITE MODEST TOTALS. TUESDAY...MODELS SHOW WHAT LITTLE LOW LEVEL MOISTURE REMAINS...TO BEGIN SCOURING OUT FROM THE WEST AS UPPER LOW PASSES THROUGH NEW MEXICO. LEFT LOW POPS IN FAR EAST IN CASE MOISTURE REMAINS INTO HEATING PERIOD. FLOW TURNS SOUTHWEST WEDNESDAY INTO SATURDAY AHEAD OF A BROAD UPPER TROUGH SLOWLY MOVING ONSHORE OF THE WEST COAST. PATTERN LOOKS LIKE IT SHOULD BE WARM...BUT MODELS NEVER REALLY DEVELOP STRONG LEE SIDE TROUGHING TO DEVELOP WARM SOUTHWEST WINDS. SO HIGH TEMPS LOOK TO REMAIN AROUND NORMAL LAST HALF OF THE WEEK. NICE DAYS WITH SEASONABLE TEMPS AND YET NOT MUCH IN THE WAY OF WINDS. && .AVIATION...VALID 04/00Z-05/00Z... VFR CONDS THRU PD. P6SM SCT-BKN080-100 BKN150-200 WITH ISOLD TO SCT VRB25G40KT -TSRA BKN070-090 THRU 04Z AND AGAIN AFT 18Z. GENERALLY W TO SW WINDS UNDER 12KTS THRU 20Z...THEN INCREASING TO 12-18G25KTS. && .FIRE WEATHER... AN UPPER LEVEL TROUGH WILL BE LIFTING OUT OF THE SOUTHWEST OVER THE NEXT COUPLE OF DAYS. THIS WILL BRING ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO THE REGION. THERE WILL BE SOME DRY LIGHTNING POSSIBLE AS TEMP-DEW POINT SPREAD WILL BE AROUND 50 DEGREES INTO THE EARLY EVENING AND AROUND 45 DEGREES ON MONDAY. WINDS WILL ALSO START TO INCREASE MONDAY AFTERNOON OUT OF THE SOUTHWEST AT 15 TO 20 MPH. TEMPERATURES WILL COOL DOWN ON THE BACK SIDE OF THIS SYSTEM INTO THE UPPER 70S TO LOWER 80S BUT RELATIVE HUMIDITIES WILL STAY AT OR BELOW 15 PERCENT FOR MOST LOWLAND LOCATIONS THROUGH THE UPCOMING WEEK. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 62 86 60 82 58 / 10 10 20 0 0 SIERRA BLANCA 57 83 54 82 54 / 20 10 40 0 0 LAS CRUCES 53 83 51 81 50 / 10 10 20 0 0 ALAMOGORDO 56 83 54 81 53 / 10 20 30 0 0 CLOUDCROFT 45 63 42 60 40 / 20 50 50 30 0 TRUTH OR CONSEQUENCES 53 81 50 79 50 / 10 20 20 10 0 SILVER CITY 48 75 46 72 45 / 10 20 30 20 0 DEMING 51 83 48 81 48 / 10 10 20 0 0 LORDSBURG 52 81 48 80 48 / 10 20 20 10 0 WEST EL PASO METRO 61 85 60 82 59 / 10 10 20 0 0 DELL CITY 55 85 54 81 52 / 20 20 40 20 0 FORT HANCOCK 58 87 56 83 55 / 20 10 30 0 0 LOMA LINDA 58 81 58 79 56 / 10 10 30 0 0 FABENS 57 86 55 82 54 / 10 10 30 0 0 SANTA TERESA 57 85 55 82 54 / 10 10 20 0 0 WHITE SANDS HQ 60 82 58 81 57 / 10 20 20 0 0 JORNADA RANGE 52 83 50 81 48 / 10 20 20 0 0 HATCH 53 83 50 82 49 / 10 20 20 0 0 COLUMBUS 55 81 54 81 53 / 10 10 20 0 0 OROGRANDE 59 84 57 82 57 / 10 20 30 0 0 MAYHILL 51 72 48 70 46 / 20 50 50 30 0 MESCALERO 49 72 45 70 43 / 20 50 50 30 0 TIMBERON 50 71 47 69 45 / 20 50 50 20 0 WINSTON 44 71 44 73 41 / 20 30 40 30 0 HILLSBORO 50 80 48 79 46 / 10 20 20 20 0 SPACEPORT 50 82 48 81 48 / 10 20 30 0 0 LAKE ROBERTS 44 74 44 71 42 / 10 30 30 30 0 HURLEY 47 76 47 75 44 / 10 10 20 20 0 CLIFF 46 80 42 78 42 / 10 20 20 30 0 MULE CREEK 42 78 39 75 39 / 20 20 20 30 0 FAYWOOD 49 77 47 76 46 / 10 10 20 20 0 ANIMAS 51 80 48 81 49 / 10 20 20 0 0 HACHITA 49 81 47 81 48 / 10 10 20 0 0 ANTELOPE WELLS 49 80 46 80 48 / 10 10 20 0 0 CLOVERDALE 48 78 47 77 47 / 10 10 10 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ HEFNER/GRZYWACZ
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1154 AM CDT SUN MAY 3 2015 .AVIATION... 18Z TAF CYCLE AN UPPER LOW WILL APPROACH THE PANHANDLES FROM THE WEST THROUGH MONDAY AND A FRONTAL BOUNDARY WILL PUSH INTO THE NORTHWEST SECTIONS OF THE PANHANDLES TONIGHT AND MONDAY. CONVECTION WILL DEVELOP AND MOVE EAST OUT OF NEW MEXICO THIS AFTERNOON AND TONIGHT OR DEVELOP ACROSS MAINLY THE WESTERN HALF OF THE PANHANDLES. WILL MENTION VCTS AT ALL THREE TAF SITES FOR NOW BETWEEN ABOUT 00Z MONDAY AND 08Z MONDAY WITH VFR CONDITIONS. LIGHT MOSTLY WEST AND SOUTHWEST WINDS 5 TO 15 KNOTS WILL INCREASE FROM THE SOUTH 10 TO 20 KNOTS WITH SOME HIGHER GUSTS POSSIBLE AFTER 20Z TODAY...THEN DIMINISHING TO AROUND 5 TO 15 KNOTS FROM THE SOUTH AND SOUTHEAST AFTER 00Z MONDAY. SCHNEIDER && .PREV DISCUSSION... /ISSUED 618 AM CDT SUN MAY 3 2015/ AVIATION... MORE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING ACROSS MUCH OF THE PANHANDLES. BUT WILL NOT MENTION THUNDERSTORMS AT THE TAF SITES AS THE COVERAGE WILL NOT BE WIDESPREAD ENOUGH TO MENTION AT THIS TIME. SKIES WILL REMAIN VFR...UNLESS A TAF SITE TAKES A DIRECT HIT FROM A THUNDERSTORM...THEN CONDITIONS WILL LIKELY DROP INTO THE MVFR RANGE. GUSTY SOUTHERLY WINDS WILL GRADUALLY DECREASE WITH SUNSET. PREV DISCUSSION... /ISSUED 520 AM CDT SUN MAY 3 2015/ DISCUSSION... NO SIGNIFICANT CHANGES WERE NEEDED TO THE PREVIOUS FORECAST. CURRENT WATER VAPOR AND RAP ANALYSIS SHOW AN UPPER LOW CURRENTLY OFF THE CALIFORNIA COAST MOVING EASTWARD. THIS WILL BE THE IMPETUS FOR WIDESPREAD POTENTIALLY HEAVY RAINFALL EARLY NEXT WEEK ACROSS THE ENTIRE FORECAST AREA. BROAD BUT WEAK UPPER LEVEL RIDGING IS PRESENT OVER THE SOUTH-CENTRAL UNITED STATES AND WILL HAVE LESS INFLUENCE ON OUR WEATHER AS IT CONTINUES TO WEAKEN AND SHIFT EASTWARD. INITIAL PRECIPITATION CHANCES WILL BE TIED TO DIURNAL CYCLE AND OROGRAPHIC EFFECTS OF THE HIGH TERRAIN IN NEW MEXICO WITH CONVECTION BECOMING FAIRLY NUMEROUS THERE BY EARLY/MID AFTERNOON. MEAN WESTERLY FLOW WILL REMAIN RATHER WEAK RESULTING IN SLOW EASTWARD PROGRESSION OF THIS CONVECTION. FURTHER EAST ONTO THE NEW MEXICO PLAINS AND ACROSS AT LEAST THE WESTERN PORTION OF THE PANHANDLES...DEEP MIXING DURING THE AFTERNOON SHOULD BE SUFFICIENT FOR SCATTERED HIGH BASED CONVECTION TO DEVELOP. DEEP DRY SUB-CLOUD LAYER WILL LIMIT PRECIPITATION AMOUNTS BUT COULD RESULT IN STRONG WIND GUSTS WITH THE MOST ROBUST CONVECTION. CONVECTION SHOULD SLOWLY WEAKEN DURING THE EVENING AND EARLY SUNDAY NIGHT. UPPER FLOW BECOMES INCREASINGLY DIFLUENT ON MONDAY AS THE UPPER LOW APPROACHES. EVEN EARLY IN THE DAY SUFFICIENT LARGE SCALE FORCING AND MOISTURE ADVECTION IS PRESENT TO JUSTIFY AT LEAST LOW PRECIPITATION PROBABILITIES PRIMARILY ACROSS THE WESTERN HALF OF THE AREA. 00Z RAOB FROM COASTAL TEXAS OFFICES STILL LACK DEEP MOISTURE BUT LATEST SATELLITE DERIVED TPW SHOWS INCREASING MOISTURE ACROSS THE WESTERN GULF. MODEL GUIDANCE IS INSISTENT ON A SURGE OF LOW LEVEL MOISTURE AND ABOVE CLIMO PWAT VALUES INTO THE AREA BY LATE MONDAY WITH STRENGTHENING LEE TROUGH AND SOUTHERLY WINDS. THIS INCREASE IN MOISTURE COMBINED WITH THE ABOVE MENTIONED LARGE SCALE FORCING SHOULD RESULT IN WIDESPREAD RAIN. SPATIAL AND TEMPORAL DETAILS OF HEAVY RAIN AND POTENTIAL FLOODING ARE STILL A BIT UNCLEAR BUT THE PATTERN FITS THESE THREATS. ONE TO THREE INCHES SEEMS LIKELY. THE MAJORITY OF THE RAINFALL WILL OCCUR MONDAY NIGHT THROUGH THE FIRST HALF OF TUESDAY. SEVERE THUNDERSTORM POTENTIAL SHOULD BE MOST LIKELY...ALBEIT STILL RELATIVELY LOW AND MARGINAL...MONDAY AFTERNOON AND EVENING COINCIDENT WITH LOW LEVEL MOISTURE SURGE BENEATH STEEPENING MID LEVEL LAPSE RATES. THIS SHOULD YIELD AT LEAST MARGINAL INSTABILITY AND DEEPER/STRONGER CONVECTION THAN THE PREVIOUS DAY. EFFECTIVE SHEAR MAY BE MARGINAL FOR STORM ORGANIZATION THOUGH. SIGNIFICANT CONVECTIVE OVERTURNING SHOULD WEAKEN MID LEVEL LAPSE RATES ON TUESDAY PRECLUDING A NOTEWORTHY SEVERE WEATHER THREAT ALTHOUGH IF POCKETS OF INSTABILITY CAN DEVELOP SOME STRONG TO SEVERE THUNDERSTORMS WOULD BE POSSIBLE. ONE OF THE FEW CHANGES THAT WERE MADE TO THE FORECAST WAS TO LOWER HIGH TEMPERATURES ON TUESDAY TO ACCOUNT FOR WIDESPREAD CLOUDS AND PRECIPITATION THAT WILL LIKELY LIMIT THE MAGNITUDE OF DIURNAL HEATING. AS UPPER LOW/OPENING WAVE DEPARTS...WEAK SHORTWAVE RIDGING WILL BRIEFLY INFLUENCE THE AREA RESULTING IN A MOSTLY DRY DAY AND TEMPERATURES RETURNING TO THE UPPER 70S AND LOWER 80S. A DEEP CLOSED LOW WILL EVOLVE ALONG THE WEST COAST BY THURSDAY AND WITH STRENGTHENING MEAN SOUTHWESTERLY FLOW LEE TROUGHING WILL PERSIST/STRENGTHEN. MULTIPLE DAYS OF DRYLINE CONVECTION MAY OCCUR FROM LATE WEEK THROUGH THE WEEKEND WITH HIGHEST PRECIPITATION PROBABILITIES ACROSS THE EASTERN HALF OF THE AREA. SPREAD IN THE ENSEMBLE AND UNCERTAINTY WITH TIMING OF SMALL LEAD WAVES AND EASTWARD PROGRESSION OF UPPER LOW MAKES IT DIFFICULT TO DELINEATE WHEN THE HIGHEST PROBABILITY OF PRECIPITATION WILL BE. SUBSEQUENT FORECASTS WILL REFINE THESE DETAILS. BRB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 11/14
AREA FORECAST DISCUSSION
NWS AMARILLO TX
520 AM CDT SUN MAY 3 2015 .DISCUSSION... NO SIGNIFICANT CHANGES WERE NEEDED TO THE PREVIOUS FORECAST. CURRENT WATER VAPOR AND RAP ANALYSIS SHOW AN UPPER LOW CURRENTLY OFF THE CALIFORNIA COAST MOVING EASTWARD. THIS WILL BE THE IMPETUS FOR WIDESPREAD POTENTIALLY HEAVY RAINFALL EARLY NEXT WEEK ACROSS THE ENTIRE FORECAST AREA. BROAD BUT WEAK UPPER LEVEL RIDGING IS PRESENT OVER THE SOUTH-CENTRAL UNITED STATES AND WILL HAVE LESS INFLUENCE ON OUR WEATHER AS IT CONTINUES TO WEAKEN AND SHIFT EASTWARD. INITIAL PRECIPITATION CHANCES WILL BE TIED TO DIURNAL CYCLE AND OROGRAPHIC EFFECTS OF THE HIGH TERRAIN IN NEW MEXICO WITH CONVECTION BECOMING FAIRLY NUMEROUS THERE BY EARLY/MID AFTERNOON. MEAN WESTERLY FLOW WILL REMAIN RATHER WEAK RESULTING IN SLOW EASTWARD PROGRESSION OF THIS CONVECTION. FURTHER EAST ONTO THE NEW MEXICO PLAINS AND ACROSS AT LEAST THE WESTERN PORTION OF THE PANHANDLES...DEEP MIXING DURING THE AFTERNOON SHOULD BE SUFFICIENT FOR SCATTERED HIGH BASED CONVECTION TO DEVELOP. DEEP DRY SUB-CLOUD LAYER WILL LIMIT PRECIPITATION AMOUNTS BUT COULD RESULT IN STRONG WIND GUSTS WITH THE MOST ROBUST CONVECTION. CONVECTION SHOULD SLOWLY WEAKEN DURING THE EVENING AND EARLY SUNDAY NIGHT. UPPER FLOW BECOMES INCREASINGLY DIFLUENT ON MONDAY AS THE UPPER LOW APPROACHES. EVEN EARLY IN THE DAY SUFFICIENT LARGE SCALE FORCING AND MOISTURE ADVECTION IS PRESENT TO JUSTIFY AT LEAST LOW PRECIPITATION PROBABILITIES PRIMARILY ACROSS THE WESTERN HALF OF THE AREA. 00Z RAOB FROM COASTAL TEXAS OFFICES STILL LACK DEEP MOISTURE BUT LATEST SATELLITE DERIVED TPW SHOWS INCREASING MOISTURE ACROSS THE WESTERN GULF. MODEL GUIDANCE IS INSISTENT ON A SURGE OF LOW LEVEL MOISTURE AND ABOVE CLIMO PWAT VALUES INTO THE AREA BY LATE MONDAY WITH STRENGTHENING LEE TROUGH AND SOUTHERLY WINDS. THIS INCREASE IN MOISTURE COMBINED WITH THE ABOVE MENTIONED LARGE SCALE FORCING SHOULD RESULT IN WIDESPREAD RAIN. SPATIAL AND TEMPORAL DETAILS OF HEAVY RAIN AND POTENTIAL FLOODING ARE STILL A BIT UNCLEAR BUT THE PATTERN FITS THESE THREATS. ONE TO THREE INCHES SEEMS LIKELY. THE MAJORITY OF THE RAINFALL WILL OCCUR MONDAY NIGHT THROUGH THE FIRST HALF OF TUESDAY. SEVERE THUNDERSTORM POTENTIAL SHOULD BE MOST LIKELY...ALBEIT STILL RELATIVELY LOW AND MARGINAL...MONDAY AFTERNOON AND EVENING COINCIDENT WITH LOW LEVEL MOISTURE SURGE BENEATH STEEPENING MID LEVEL LAPSE RATES. THIS SHOULD YIELD AT LEAST MARGINAL INSTABILITY AND DEEPER/STRONGER CONVECTION THAN THE PREVIOUS DAY. EFFECTIVE SHEAR MAY BE MARGINAL FOR STORM ORGANIZATION THOUGH. SIGNIFICANT CONVECTIVE OVERTURNING SHOULD WEAKEN MID LEVEL LAPSE RATES ON TUESDAY PRECLUDING A NOTEWORTHY SEVERE WEATHER THREAT ALTHOUGH IF POCKETS OF INSTABILITY CAN DEVELOP SOME STRONG TO SEVERE THUNDERSTORMS WOULD BE POSSIBLE. ONE OF THE FEW CHANGES THAT WERE MADE TO THE FORECAST WAS TO LOWER HIGH TEMPERATURES ON TUESDAY TO ACCOUNT FOR WIDESPREAD CLOUDS AND PRECIPITATION THAT WILL LIKELY LIMIT THE MAGNITUDE OF DIURNAL HEATING. AS UPPER LOW/OPENING WAVE DEPARTS...WEAK SHORTWAVE RIDGING WILL BRIEFLY INFLUENCE THE AREA RESULTING IN A MOSTLY DRY DAY AND TEMPERATURES RETURNING TO THE UPPER 70S AND LOWER 80S. A DEEP CLOSED LOW WILL EVOLVE ALONG THE WEST COAST BY THURSDAY AND WITH STRENGTHENING MEAN SOUTHWESTERLY FLOW LEE TROUGHING WILL PERSIST/STRENGTHEN. MULTIPLE DAYS OF DRYLINE CONVECTION MAY OCCUR FROM LATE WEEK THROUGH THE WEEKEND WITH HIGHEST PRECIPITATION PROBABILITIES ACROSS THE EASTERN HALF OF THE AREA. SPREAD IN THE ENSEMBLE AND UNCERTAINTY WITH TIMING OF SMALL LEAD WAVES AND EASTWARD PROGRESSION OF UPPER LOW MAKES IT DIFFICULT TO DELINEATE WHEN THE HIGHEST PROBABILITY OF PRECIPITATION WILL BE. SUBSEQUENT FORECASTS WILL REFINE THESE DETAILS. BRB && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 84 59 75 57 64 / 20 30 50 80 80 BEAVER OK 89 60 82 60 66 / 20 30 40 70 80 BOISE CITY OK 84 56 75 54 65 / 30 30 60 80 70 BORGER TX 87 60 78 59 65 / 20 30 50 80 80 BOYS RANCH TX 87 59 78 58 66 / 30 40 60 80 80 CANYON TX 85 59 75 57 65 / 20 30 60 80 80 CLARENDON TX 84 60 76 59 65 / 10 30 30 70 80 DALHART TX 85 56 76 55 66 / 40 30 60 80 80 GUYMON OK 87 58 79 58 65 / 30 30 60 80 80 HEREFORD TX 85 58 76 57 65 / 30 30 60 80 80 LIPSCOMB TX 85 60 79 60 65 / 20 30 30 70 80 PAMPA TX 83 58 76 57 63 / 20 30 40 80 80 SHAMROCK TX 83 60 77 60 66 / 10 20 30 70 80 WELLINGTON TX 85 61 78 61 68 / 5 20 30 60 80 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 15/17
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 948 PM CDT MON MAY 4 2015 HAVE MADE SOME CHANGES TO THE MORNING RAIN CHANCES...HAVE INCREASED THEM NORTHWARD INTO THE I-90 CORRIDOR BUT SLIGHTLY OFFSET HIGHER IN WI. HAVE BEEN WATCHING RUN AFTER RUN OF THE HRRR AND RAP MODELS COME IN THIS EVENING WITH CONSISTENT LIGHT PRECIPITATION FORECAST OVER THE I-90 CORRIDOR BY SUNRISE. WHILE THIS ADDED TO THE CONFIDENCE...WAS WAITING TO SEE ANOTHER MODEL PLATFORM INDICATE THE SAME TO LEND MORE CONFIDENCE TO THE FORECAST. THE 05.00Z NAM HAS NOW MADE THIS SAME CHANGE NORTHWARD. THIS IS IN RESPONSE TO FAIRLY STRONG 600-800MB FRONTOGENESIS ROTATING NORTHEAST TONIGHT FROM DES MOINES TO GREEN BAY ON THE NORTH SIDE OF THE SHORTWAVE JUST EAST OF OMAHA PER RADAR. THE EASTERLY DRY FLOW BELOW 5-8KFT WILL EVAPORATE SOME OF THE PRECIPITATION...BUT HAVE DECIDED TO INCREASE TO MID-RANGE RAIN CHANCES /50 PERCENT/ IN THE EARLY MORNING TO BEGIN A TREND. UPDATE ISSUED AT 648 PM CDT MON MAY 4 2015 HAVE INCREASED THE RAIN CHANCES EARLY THIS EVENING ACROSS THE FAR SOUTH BASED ON RADAR AND SURFACE OBSERVATIONS OF VERY LIGHT RAIN. CLEARLY A NORTHERN EDGE TO THE DEFORMATION AREA IS SEEN ON THE RADAR AT THIS TIME WITH PLENTY OF ECHO AND RAIN DEVELOPMENT AHEAD OF THE SHORTWAVE TROUGH HEADING E-NE FROM NEBRASKA. MODEL GUIDANCE DOES SHOW MID-LEVEL FRONTOGENESIS CURRENTLY ASSOCIATED WITH THE RAIN BAND ACROSS IOWA SHIFTING NORTHEASTWARD INTO THE FORECAST AREA TOWARD KGRB. INTERESTINGLY...THE RAP TAKES THIS FEATURE TO I-90 BY MORNING AND LATEST RAP AND HRRR MODELS ARE PRODUCING PRECIPITATION IN THAT CORRIDOR. 04.18Z NAM AND GFS WILL HAVE NO PART OF IT WITH MUCH WEAKER FORCING. INTERESTING TO SEE NO PRECIPITATION SPLASHING NORTH OF THE GFS RAIN SCHIELD...THIS DUE TO NO CONVECTIVE INSTABILITY FOR THE MODEL TO DRIBBLE OUT ITS SUMMER SPLASHES. CURRENT FORECAST DOES HAVE RAIN CHANCES NORTH TO I-90 BY MORNING /20 PERCENT/ AND WILL CONTINUE TO MONITOR/ADJUST THIS AS THE EVENING PROGRESSES. CERTAINLY THE LOW-LEVEL DRY EASTERLY FLOW WILL NEED TO BE OVERCOME BY STRONGER FORCING SUGGESTED IN THE RAP TO GET RAINFALL TO I-90. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 339 PM CDT MON MAY 4 2015 AT 3 PM...A STATIONARY FRONT WAS LOCATED FROM CHICAGO TO KANSAS CITY. NORTH OF THIS FRONT...DEW POINTS ARE IN THE 60S AS FAR NORTH AS CENTRAL IOWA AND NORTHERN ILLINOIS. NORTH OF THIS AREA...NORTH AND NORTHEAST WINDS HAVE LOWERED DEW POINTS INTO THE 30S AND 40S. FOR TONIGHT AND TUESDAY MORNING...A SHORT WAVE TROUGH...CURRENTLY LOCATED OVER NEBRASKA...WILL MOVE EAST NORTHEAST THROUGH IOWA...AND SOUTHERN WISCONSIN ON TUESDAY. WHILE THE 925 AND 850 MB MOISTURE TRANSPORT WILL BE WEAK...STRONG 900 TO 500 MB FRONTOGENESIS WILL PRODUCE SHOWERS AND THUNDERSTORMS MAINLY SOUTH OF INTERSTATE 90 FROM LATE THIS EVENING THROUGH TUESDAY MORNING. WITH BOTH THE 0-3 KM AND 0-6 KM SHEAR BEING VERY WEAK AND MOST UNSTABLE CAPE LESS THAN 500 J/KG...NOT ANTICIPATING ANY SEVERE WEATHER. ON TUESDAY AFTERNOON...SUBSIDENCE IN THE WAKE OF THE SHORT TROUGH WILL DEVELOP ACROSS THE AREA. BOTH THE ARW AND NMM SUGGEST THAT THE AREA WILL BECOME DRY. MEANWHILE MANY OF THE DETERMINISTIC RUNS SUGGEST THAT SOME PRECIPITATION WILL LINGER INTO THE AFTERNOON. WAS VERY TEMPTED TO LEAN TOWARD THE MESO MODELS. HOWEVER CONSENSUS WAS MORE TOWARD THE DETERMINISTIC RUNS...SO WENT TOWARD THEM. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 339 PM CDT MON MAY 4 2015 FROM TUESDAY NIGHT INTO WEDNESDAY...THE 04/12Z MODELS CONTINUE TO SHOW THAT A SHORT WAVE RIDGE WILL MOVE AHEAD OF THE LONG WAVE TROUGH. THIS WILL HELP THE WARM FRONT TO ADVANCE NORTHWARD ACROSS THE AREA. WITH THE BEST 925 MB AND 850 MB MOISTURE ADVANCING QUICKLY NORTH THROUGH THE AREA...NOT AS SEEING MUCH CONVERGENCE OUTSIDE OF THE WARM FRONT ITSELF. AS A RESULT...THERE WILL BE THE POTENTIAL FOR SOME DRY WEATHER IN THE WARM SECTOR OF THIS SYSTEM ON WEDNESDAY MORNING AND POSSIBLY WEDNESDAY AFTERNOON. THIS IS HIGHLY DEPENDENT ON THE LOCATION OF THE COLD FRONT. WITH WEAK 0-3 KM AND 0-6 KM SHEAR...NO SEVERE WEATHER IS ANTICIPATED WITH THE PASSAGE OF THE WARM FRONT THROUGH THE REGION. ON THURSDAY NIGHT AND FRIDAY...THE COLD FRONT WILL FINALLY MOVE EAST THROUGH THE REGION. MOST UNSTABLE CAPES AHEAD OF THIS FRONT WILL CLIMB INTO THE 1500 TO 2500 J/KG RANGE. WHILE THE 0-6 KM SHEAR REMAINS WEAK...THE 0-3 KM SHEAR DOES CLIMB UP TO 30 KNOTS....SO MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME DAMAGING WINDS. ON SUNDAY NIGHT AND MONDAY...ANOTHER LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION. AT THIS TIME...IT LOOKS LIKE THE WARM SECTOR WILL REMAIN SOUTHEAST OF THE AREA. THIS WILL GREATLY LIMIT THE 0-6 KM SHEAR AND INSTABILITY ACROSS THE REGION. THUS NOT ANTICIPATING ANY SEVERE WEATHER AT THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1056 PM CDT MON MAY 4 2015 VFR CONDITIONS EXPECTED THROUGH THE CYCLE. HOWEVER...AS A WEATHER SYSTEM MOVES THROUGH IOWA AND INTO SOUTHERN WI...RAIN SHOWERS COULD MAKE THERE WAY INTO THE AIRFIELDS...ESPECIALLY KLSE. THIS MAY PROVIDE SOME LOWERING TO THE FORECAST CIGS IN THE 09-15Z WINDOW. HOWEVER...AT THIS TIME...THE FORECAST IS FOR THE DRY EASTERLY FLOW TO HELP KEEP CIGS MORE ELEVATED AND IN THE LOWER VFR CATEGORY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
948 PM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 948 PM CDT MON MAY 4 2015 HAVE MADE SOME CHANGES TO THE MORNING RAIN CHANCES...HAVE INCREASED THEM NORTHWARD INTO THE I-90 CORRIDOR BUT SLIGHTLY OFFSET HIGHER IN WI. HAVE BEEN WATCHING RUN AFTER RUN OF THE HRRR AND RAP MODELS COME IN THIS EVENING WITH CONSISTENT LIGHT PRECIPITATION FORECAST OVER THE I-90 CORRIDOR BY SUNRISE. WHILE THIS ADDED TO THE CONFIDENCE...WAS WAITING TO SEE ANOTHER MODEL PLATFORM INDICATE THE SAME TO LEND MORE CONFIDENCE TO THE FORECAST. THE 05.00Z NAM HAS NOW MADE THIS SAME CHANGE NORTHWARD. THIS IS IN RESPONSE TO FAIRLY STRONG 600-800MB FRONTOGENESIS ROTATING NORTHEAST TONIGHT FROM DES MOINES TO GREEN BAY ON THE NORTH SIDE OF THE SHORTWAVE JUST EAST OF OMAHA PER RADAR. THE EASTERLY DRY FLOW BELOW 5-8KFT WILL EVAPORATE SOME OF THE PRECIPITATION...BUT HAVE DECIDED TO INCREASE TO MID-RANGE RAIN CHANCES /50 PERCENT/ IN THE EARLY MORNING TO BEGIN A TREND. UPDATE ISSUED AT 648 PM CDT MON MAY 4 2015 HAVE INCREASED THE RAIN CHANCES EARLY THIS EVENING ACROSS THE FAR SOUTH BASED ON RADAR AND SURFACE OBSERVATIONS OF VERY LIGHT RAIN. CLEARLY A NORTHERN EDGE TO THE DEFORMATION AREA IS SEEN ON THE RADAR AT THIS TIME WITH PLENTY OF ECHO AND RAIN DEVELOPMENT AHEAD OF THE SHORTWAVE TROUGH HEADING E-NE FROM NEBRASKA. MODEL GUIDANCE DOES SHOW MID-LEVEL FRONTOGENESIS CURRENTLY ASSOCIATED WITH THE RAIN BAND ACROSS IOWA SHIFTING NORTHEASTWARD INTO THE FORECAST AREA TOWARD KGRB. INTERESTINGLY...THE RAP TAKES THIS FEATURE TO I-90 BY MORNING AND LATEST RAP AND HRRR MODELS ARE PRODUCING PRECIPITATION IN THAT CORRIDOR. 04.18Z NAM AND GFS WILL HAVE NO PART OF IT WITH MUCH WEAKER FORCING. INTERESTING TO SEE NO PRECIPITATION SPLASHING NORTH OF THE GFS RAIN SCHIELD...THIS DUE TO NO CONVECTIVE INSTABILITY FOR THE MODEL TO DRIBBLE OUT ITS SUMMER SPLASHES. CURRENT FORECAST DOES HAVE RAIN CHANCES NORTH TO I-90 BY MORNING /20 PERCENT/ AND WILL CONTINUE TO MONITOR/ADJUST THIS AS THE EVENING PROGRESSES. CERTAINLY THE LOW-LEVEL DRY EASTERLY FLOW WILL NEED TO BE OVERCOME BY STRONGER FORCING SUGGESTED IN THE RAP TO GET RAINFALL TO I-90. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 339 PM CDT MON MAY 4 2015 AT 3 PM...A STATIONARY FRONT WAS LOCATED FROM CHICAGO TO KANSAS CITY. NORTH OF THIS FRONT...DEW POINTS ARE IN THE 60S AS FAR NORTH AS CENTRAL IOWA AND NORTHERN ILLINOIS. NORTH OF THIS AREA...NORTH AND NORTHEAST WINDS HAVE LOWERED DEW POINTS INTO THE 30S AND 40S. FOR TONIGHT AND TUESDAY MORNING...A SHORT WAVE TROUGH...CURRENTLY LOCATED OVER NEBRASKA...WILL MOVE EAST NORTHEAST THROUGH IOWA...AND SOUTHERN WISCONSIN ON TUESDAY. WHILE THE 925 AND 850 MB MOISTURE TRANSPORT WILL BE WEAK...STRONG 900 TO 500 MB FRONTOGENESIS WILL PRODUCE SHOWERS AND THUNDERSTORMS MAINLY SOUTH OF INTERSTATE 90 FROM LATE THIS EVENING THROUGH TUESDAY MORNING. WITH BOTH THE 0-3 KM AND 0-6 KM SHEAR BEING VERY WEAK AND MOST UNSTABLE CAPE LESS THAN 500 J/KG...NOT ANTICIPATING ANY SEVERE WEATHER. ON TUESDAY AFTERNOON...SUBSIDENCE IN THE WAKE OF THE SHORT TROUGH WILL DEVELOP ACROSS THE AREA. BOTH THE ARW AND NMM SUGGEST THAT THE AREA WILL BECOME DRY. MEANWHILE MANY OF THE DETERMINISTIC RUNS SUGGEST THAT SOME PRECIPITATION WILL LINGER INTO THE AFTERNOON. WAS VERY TEMPTED TO LEAN TOWARD THE MESO MODELS. HOWEVER CONSENSUS WAS MORE TOWARD THE DETERMINISTIC RUNS...SO WENT TOWARD THEM. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 339 PM CDT MON MAY 4 2015 FROM TUESDAY NIGHT INTO WEDNESDAY...THE 04/12Z MODELS CONTINUE TO SHOW THAT A SHORT WAVE RIDGE WILL MOVE AHEAD OF THE LONG WAVE TROUGH. THIS WILL HELP THE WARM FRONT TO ADVANCE NORTHWARD ACROSS THE AREA. WITH THE BEST 925 MB AND 850 MB MOISTURE ADVANCING QUICKLY NORTH THROUGH THE AREA...NOT AS SEEING MUCH CONVERGENCE OUTSIDE OF THE WARM FRONT ITSELF. AS A RESULT...THERE WILL BE THE POTENTIAL FOR SOME DRY WEATHER IN THE WARM SECTOR OF THIS SYSTEM ON WEDNESDAY MORNING AND POSSIBLY WEDNESDAY AFTERNOON. THIS IS HIGHLY DEPENDENT ON THE LOCATION OF THE COLD FRONT. WITH WEAK 0-3 KM AND 0-6 KM SHEAR...NO SEVERE WEATHER IS ANTICIPATED WITH THE PASSAGE OF THE WARM FRONT THROUGH THE REGION. ON THURSDAY NIGHT AND FRIDAY...THE COLD FRONT WILL FINALLY MOVE EAST THROUGH THE REGION. MOST UNSTABLE CAPES AHEAD OF THIS FRONT WILL CLIMB INTO THE 1500 TO 2500 J/KG RANGE. WHILE THE 0-6 KM SHEAR REMAINS WEAK...THE 0-3 KM SHEAR DOES CLIMB UP TO 30 KNOTS....SO MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME DAMAGING WINDS. ON SUNDAY NIGHT AND MONDAY...ANOTHER LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION. AT THIS TIME...IT LOOKS LIKE THE WARM SECTOR WILL REMAIN SOUTHEAST OF THE AREA. THIS WILL GREATLY LIMIT THE 0-6 KM SHEAR AND INSTABILITY ACROSS THE REGION. THUS NOT ANTICIPATING ANY SEVERE WEATHER AT THIS TIME. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 648 PM CDT MON MAY 4 2015 VFR CONDITIONS ARE FORECAST AT THE TAF SITES. A VIGOROUS WEATHER SYSTEM MOVING THROUGH IOWA AND ILLINOIS WILL SPREAD RAIN INTO AREAS SOUTH OF THE TAF AIRFIELDS. BY SUNRISE...THERE MAY BE SOME LOWER CIGS IN THE HIGH MVFR CATEGORY WITH -SHRA. FOR NOW...THE FORECAST HAS THE DRIER EASTERLY FLOW WINNING OUT AND THE CIGS REMAINING VFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
648 PM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 648 PM CDT MON MAY 4 2015 HAVE INCREASED THE RAIN CHANCES EARLY THIS EVENING ACROSS THE FAR SOUTH BASED ON RADAR AND SURFACE OBSERVATIONS OF VERY LIGHT RAIN. CLEARLY A NORTHERN EDGE TO THE DEFORMATION AREA IS SEEN ON THE RADAR AT THIS TIME WITH PLENTY OF ECHO AND RAIN DEVELOPMENT AHEAD OF THE SHORTWAVE TROUGH HEADING E-NE FROM NEBRASKA. MODEL GUIDANCE DOES SHOW MID-LEVEL FRONTOGENESIS CURRENTLY ASSOCIATED WITH THE RAIN BAND ACROSS IOWA SHIFTING NORTHEASTWARD INTO THE FORECAST AREA TOWARD KGRB. INTERESTINGLY...THE RAP TAKES THIS FEATURE TO I-90 BY MORNING AND LATEST RAP AND HRRR MODELS ARE PRODUCING PRECIPITATION IN THAT CORRIDOR. 04.18Z NAM AND GFS WILL HAVE NO PART OF IT WITH MUCH WEAKER FORCING. INTERESTING TO SEE NO PRECIPITATION SPLASHING NORTH OF THE GFS RAIN SCHIELD...THIS DUE TO NO CONVECTIVE INSTABILITY FOR THE MODEL TO DRIBBLE OUT ITS SUMMER SPLASHES. CURRENT FORECAST DOES HAVE RAIN CHANCES NORTH TO I-90 BY MORNING /20 PERCENT/ AND WILL CONTINUE TO MONITOR/ADJUST THIS AS THE EVENING PROGRESSES. CERTAINLY THE LOW-LEVEL DRY EASTERLY FLOW WILL NEED TO BE OVERCOME BY STRONGER FORCING SUGGESTED IN THE RAP TO GET RAINFALL TO I-90. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 339 PM CDT MON MAY 4 2015 AT 3 PM...A STATIONARY FRONT WAS LOCATED FROM CHICAGO TO KANSAS CITY. NORTH OF THIS FRONT...DEW POINTS ARE IN THE 60S AS FAR NORTH AS CENTRAL IOWA AND NORTHERN ILLINOIS. NORTH OF THIS AREA...NORTH AND NORTHEAST WINDS HAVE LOWERED DEW POINTS INTO THE 30S AND 40S. FOR TONIGHT AND TUESDAY MORNING...A SHORT WAVE TROUGH...CURRENTLY LOCATED OVER NEBRASKA...WILL MOVE EAST NORTHEAST THROUGH IOWA...AND SOUTHERN WISCONSIN ON TUESDAY. WHILE THE 925 AND 850 MB MOISTURE TRANSPORT WILL BE WEAK...STRONG 900 TO 500 MB FRONTOGENESIS WILL PRODUCE SHOWERS AND THUNDERSTORMS MAINLY SOUTH OF INTERSTATE 90 FROM LATE THIS EVENING THROUGH TUESDAY MORNING. WITH BOTH THE 0-3 KM AND 0-6 KM SHEAR BEING VERY WEAK AND MOST UNSTABLE CAPE LESS THAN 500 J/KG...NOT ANTICIPATING ANY SEVERE WEATHER. ON TUESDAY AFTERNOON...SUBSIDENCE IN THE WAKE OF THE SHORT TROUGH WILL DEVELOP ACROSS THE AREA. BOTH THE ARW AND NMM SUGGEST THAT THE AREA WILL BECOME DRY. MEANWHILE MANY OF THE DETERMINISTIC RUNS SUGGEST THAT SOME PRECIPITATION WILL LINGER INTO THE AFTERNOON. WAS VERY TEMPTED TO LEAN TOWARD THE MESO MODELS. HOWEVER CONSENSUS WAS MORE TOWARD THE DETERMINISTIC RUNS...SO WENT TOWARD THEM. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 339 PM CDT MON MAY 4 2015 FROM TUESDAY NIGHT INTO WEDNESDAY...THE 04/12Z MODELS CONTINUE TO SHOW THAT A SHORT WAVE RIDGE WILL MOVE AHEAD OF THE LONG WAVE TROUGH. THIS WILL HELP THE WARM FRONT TO ADVANCE NORTHWARD ACROSS THE AREA. WITH THE BEST 925 MB AND 850 MB MOISTURE ADVANCING QUICKLY NORTH THROUGH THE AREA...NOT AS SEEING MUCH CONVERGENCE OUTSIDE OF THE WARM FRONT ITSELF. AS A RESULT...THERE WILL BE THE POTENTIAL FOR SOME DRY WEATHER IN THE WARM SECTOR OF THIS SYSTEM ON WEDNESDAY MORNING AND POSSIBLY WEDNESDAY AFTERNOON. THIS IS HIGHLY DEPENDENT ON THE LOCATION OF THE COLD FRONT. WITH WEAK 0-3 KM AND 0-6 KM SHEAR...NO SEVERE WEATHER IS ANTICIPATED WITH THE PASSAGE OF THE WARM FRONT THROUGH THE REGION. ON THURSDAY NIGHT AND FRIDAY...THE COLD FRONT WILL FINALLY MOVE EAST THROUGH THE REGION. MOST UNSTABLE CAPES AHEAD OF THIS FRONT WILL CLIMB INTO THE 1500 TO 2500 J/KG RANGE. WHILE THE 0-6 KM SHEAR REMAINS WEAK...THE 0-3 KM SHEAR DOES CLIMB UP TO 30 KNOTS....SO MAY HAVE TO WATCH FOR THE POTENTIAL FOR SOME DAMAGING WINDS. ON SUNDAY NIGHT AND MONDAY...ANOTHER LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION. AT THIS TIME...IT LOOKS LIKE THE WARM SECTOR WILL REMAIN SOUTHEAST OF THE AREA. THIS WILL GREATLY LIMIT THE 0-6 KM SHEAR AND INSTABILITY ACROSS THE REGION. THUS NOT ANTICIPATING ANY SEVERE WEATHER AT THIS TIME. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 648 PM CDT MON MAY 4 2015 VFR CONDITIONS ARE FORECAST AT THE TAF SITES. A VIGOROUS WEATHER SYSTEM MOVING THROUGH IOWA AND ILLINOIS WILL SPREAD RAIN INTO AREAS SOUTH OF THE TAF AIRFIELDS. BY SUNRISE...THERE MAY BE SOME LOWER CIGS IN THE HIGH MVFR CATEGORY WITH -SHRA. FOR NOW...THE FORECAST HAS THE DRIER EASTERLY FLOW WINNING OUT AND THE CIGS REMAINING VFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...BAUMGARDT
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND MONDAY ISSUED AT 327 PM CDT SUN MAY 3 2015 TIMING AND INTENSITY OF THUNDERSTORMS ARE THE MAIN CONCERNS DURING THIS PART OF THE FORECAST. A COLD FRONT MOVED INTO EXTREME NORTHWEST WISCONSIN THIS AFTERNOON AND RADAR AND LIGHTNING DETECTION DATA INDICATED A LINE OF THUNDERSTORMS AHEAD OF THE FRONT ACROSS THE FAR NORTHWEST PART OF THE STATE...ALONG WITH WIDESPREAD CONVECTION IN UPPER MICHIGAN...AT 1945Z. LOCAL MESOANALYSIS GRAPHICS WERE SHOWING 1000+J/KG OF MUCAPE IN NORTH CENTRAL WISCONSIN WITH LITTLE TO NO CIN SINCE ABOUT 16Z. BY 19Z MUCAPE VALUES ACROSS MOST OF THE REST OF THE AREA WERE MAINLY IN THE 250-1000J/KG RANGE...WITH LESS THAN 250J/KG GENERALLY EAST OF A LINE FROM ABOUT WAUSAUKEE TO OSHKOSH. WOULD EXPECT STORMS TO CONTINUE AS THE FRONT REACHES THE UNSTABLE AIR IN THE NORTHERN PART OF THE STATE. 12Z MODELS GENERALLY SHOWED QPF SPREADING ACROSS THE ENTIRE AREA BETWEEN 18Z AND 00Z MONDAY. BUT MESOSCALE MODELS...ARW/HRRR...DID NOT HAVE PRECIPITATION REACHING NORTH CENTRAL WISCONSIN UNTIL SHORTLY BEFORE 00Z MONDAY WITH ONLY ISOLATED SMALL VALUES OF QPF ACROSS THE REST OF THE AREA. MESO MODELS APPEARED TO BE DOING A BETTER JOB OF HANDLING THE SITUATION SO HAVE SLOWED THE PROGRESSION OF THE CONVECTION ACROSS THE AREA. SPC HAS KEPT THE MAJORITY OF THE AREA IN A SLIGHT RISK FOR SEVERE STORMS THIS AFTERNOON AND EVENING. WBZ HEIGHTS AT 20Z RANGED FROM LESS THAN 7500FT IN NORTH CENTRAL WISCONSIN TO MORE THAN 9000FT IN EAST CENTRAL WISCONSIN. 0-6KM SHEAR ACROSS THE NORTH WAS MAINLY 25-35KTS. THERE IS NOT QUITE AS MUCH INSTABILITY AS MODELS SHOWED YESTERDAY...SHEAR WAS NOT ALL THAT IMPRESSIVE AND THERE IS NOT A LOT OF UPPER SUPPORT AVAILABLE...SO STRENGTH OF THE STORMS IS A BIT UNCERTAIN. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 327 PM CDT SUN MAY 3 2015 THE TRAILING END OF THE COLD FRONT WILL STALL OVER NORTHERN ILLINOIS AND SERVE AS A WEAK FOCAL POINT FOR SHOWERS DURING THE FIRST HALF OF THE WEEK AS IT GRADUALLY PUSHES NORTH-NORTHEAST OVER WISCONSIN AND WASHES OUT. MEANWHILE...A BROAD SFC-500MB HIGH PRESSURE RIDGE WILL SPREAD IN FROM THE WEST AS THE WEEK PROGRESSES. THE RIDGE AXIS WILL MOVE EAST OF WISCONSIN BY THE END OF THE WORK WEEK. GFS AND ECMWF MODELS ARE IN AGREEMENT THAT WISCONSIN WILL THEN REMAIN UNDER THE UNSTABLE WEST SIDE OF THE RIDGE THROUGH THE WEEKEND...ENABLING GULF MOISTURE TO ADVECT INTO WISCONSIN FROM THE SOUTHWEST...ALONG WITH A DISTURBANCE OR TWO. ML. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 104 PM CDT SUN MAY 3 2015 CONDITIONS WERE VFR ACROSS THE AREA AT MIDDAY AS A COLD FRONT WAS JUST ENTERING THE NORTHWEST CORNER OF WISCONSIN. CONFIDENCE HAS WANED WITH REGARD TO FORECAST OF CONVECTION ACROSS THE AREA THIS AFTERNOON INTO MONDAY MORNING. ONLY MADE MINOR ADJUSTMENTS TO TIMING FROM THE PREVIOUS FORECAST FOR NOW. THE MOST UNSTABLE CONDITIONS APPEARED TO BE ACROSS NORTH CENTRAL WISCONSIN WHERE MUCAPE VALUES WERE 500+ J/KG WITH LITTLE TO NO CIN THERE...BUT NO CONVECTION WAS YET EVIDENT IN THAT AREA. SHOWERS AND ISOLATED THUNDERSTORMS WERE CONFINED TO MINNESOTA AND EASTERN LAKE SUPERIOR AT 1745Z. MOST OF THE 12Z MODELS SHOWED QPF WITH THE FRONT GREATLY EXPANDING DURING THE AFTERNOON TO COVER THE ENTIRE AREA. A QUICK LOOK AT THE 16Z HRRR INDICATED ISOLATED-SCATTERED LIGHT QPF UNTIL A MORE SOLID AREA OF PRECIPITATION REACHES NORTH CENTRAL WISCONSIN. THIS LOOKS LIKE ITS ON TRACK...AT LEAST RIGHT NOW...SO MAINLY VFR AND DRY THE REST OF THE DAY IF IT REMAINS ON TRACK. CANNOT RULE OUT CONVECTIVE DEVELOPMENT WITH SPC DAY 1 SEVERE OUTLOOK INCLUDING MUCH OF THE AREA IN A SLIGHT RISK FOR SEVERE...WITH POSSIBLE DAMAGING WINDS AND LARGE HAIL THIS AFTERNOON AND TONIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MG LONG TERM......ML AVIATION.......MG
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
104 PM CDT SUN MAY 3 2015 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND MONDAY ISSUED AT 338 AM CDT SUN MAY 3 2015 THUNDERSTORM TIMING TODAY INTO TONIGHT AS WELL AS POTENTIAL OF SEVERE STORMS THE PRIMARY ISSUE FOR THIS PERIOD. RADARS THIS MORNING SHOW SCATTERED SHOWERS AND STORMS OVER MINNESOTA AHEAD OF THE COLD FRONT AND ANOTHER CLUSTER OF SHOWERS AND STORMS OVER IOWA ASSOCIATED WITH A WEAK SHORT WAVE DRIFTING IN THE WEST TO SOUTHWEST FLOW. THIS IOWA SHORT WAVE TROUGH IS PROGGED TO STAY SOUTH BUT DID NOTICE SOME MID LEVEL CLOUDS GRADUALLY DRIFTING NORTHEASTWARD INTO SOUTHWEST WISCONSIN. PROGS OVERALL KEEP THIS CONVECTION SOUTH BUT A FEW DO EXTEND SOME LIGHT AMOUNTS INTO PARTS OF CENTRAL AND EAST CENTRAL WISCONSIN LATER THIS MORNING. OTHERWISE THE BRUNT OF THE CONVECTION TODAY WILL BE WITH THE CONVERGENCE GENERATED ALONG THE COLD FRONT. UPPER JET SUPPORT WELL NORTH OF THE AREA. WILL HAVE AN EARLIER START TIME OF THE CONVECTION AROUND MID DAY FOR NORTH CENTRAL DUE TO POSSIBLE EARLY MORNING MINNESOTA CONVECTION MAY HOLD TOGETHER AND REACH THIS AREA. STRONGEST STORMS WILL LIKELY ARRIVE MID TO LATE AFTERNOON OVER NORTH CENTRAL WISCONSIN AND CENTRAL WISCONSIN DURING PEAK HEATING PERIOD. SPC CONTINUES TO PLACE MUCH OF CENTRAL AND NORTH CENTRAL IN A SLIGHT RISK. SOME MODEL ISSUES WITH RESPECT TO AVAILABLE INSTABILITY DUE TO SURFACE DEWPOINTS TRENDS...NAM PRODUCES UP TO 2000 J/KG CAPES LATE THIS AFTERNOON OVER CENTRAL AND NORTH CENTRAL WISCONSIN WHILE THE GFS FORECAST SOUNDINGS ARE BETWEEN 100O TO 1500. SOME LOWER TO MID 50S NOTED OVER THE CENTRAL PLAINS AND ANTICIPATE SIMILAR VALUES LATER TODAY ALONG AND JUST AHEAD OF THE COLD FRONT. CAPES OF 1000 TO 1500 J/KG WILL BE WORKING WITH AN INCREASINGLY SHEARED ENVIRONMENT DUE TO THE MID LEVEL WESTERLY FLOW. BY THE TIME THE STORMS REACH EAST CENTRAL WISCONSIN LATER THIS EVENING...INSTABILITY DUE TO DAYTIME HEATING WILL DIMINISH...BUT THE WESTERLY MID LEVEL WINDS WILL WORK INTO THE AREA AS THE COLD FRONT PASSES. THE LINGERING SHEARED ENVIRONMENT MAY BE ENOUGH TO MAINTAIN A FEW NEAR SEVERE STORMS THIS EVENING OVER EAST CENTRAL WISCONSIN. SHOWERS AND STORMS WILL BE ON THE DECREASE AFTER MIDNIGHT AND TOWARD MONDAY MORNING AFTER FROPA. HIGH PRESSURE WILL BUILD INTO NORTHWEST WISCONSIN MONDAY FOR SUNNY SKIES ACROSS THE NORTH. SINCE THE COLD FRONT STALLS OVER NORTHERN OR CENTRAL ILLINOIS...CLOUDS MAY HANG AROUND OVER EAST CENTRAL WISCONSIN. NORTHEAST WINDS OFF THE LAKE MAY ALSO CONTRIBUTE TO LOWER LEVEL CLOUDS MONDAY. DUE TO CLOUDS SUNDAY NIGHT...AND A WARM START MONDAY MORNING AND DECREASING CLOUDS MONDAY...FORECAST MAX TEMPERATURES MAY REBOUND INTO AT LEAST THE LOWER 70S AWAY FROM LAKE MICHIGAN AND THE BAY. .LONG TERM...MONDAY NIGHT THROUGH SATURDAY ISSUED AT 338 AM CDT SUN MAY 3 2015 AMPLIFIED MEAN FLOW TO PERSIST THRU MUCH OF THE WEEK WITH A BROAD UPR TROF OVER THE WRN CONUS AND AN UPR RDG OVER THE SE CONUS. THIS PATTERN WOULD BRING A PREVAILING SW FLOW TO THE CNTRL CONUS (INCLUDING WI) WHICH WL KEEP TEMPS ABOVE NORMAL AND ALLOW GULF MOISTURE TO EASILY FLOW NWD. AN ACTIVE WEATHER PERIOD IS EXPECTED FOR NE WI AS A WRMFNT MOVES THRU THE AREA LATE TUE INTO WED... FOLLOWED BY A WEAKENING SHORTWAVE TROF/SFC CDFNT LATE IN THE WEEK. THE EXPECTED PCPN SHOULD HELP TO ALLEVIATE THE DRY CONDITIONS/FIRE DANGER OVER THE REGION. THE SFC HI WL SLOWLY SHIFT TOWARD NE SECTIONS OF THE GREAT LAKES TUE NGT...BUT KEEP A DRY E-NE WIND OVER THE FCST AREA. MEANWHILE... WL BE WATCHING THE STALLED BOUNDARY TO OUR SOUTH WHICH MAY EDGE A BIT NORTH IN RESPONSE TO AN INCREASING LOW-LEVEL JET OVER THE PLAINS. NRN WI TO REMAIN MOSTLY CLEAR THRU THE NGT...HOWEVER EXPECT CNTRL/E-CNTRL WI TO BECOME PARTLY TO MOSTLY CLOUDY OVRNGT AND CANNOT RULE OUT A FEW LIGHT SHWRS REACHING OUR SRN TIER OF COUNTIES TOWARD DAYBREAK AS ADDITIONAL SHWRS/TSTMS MOVE ALONG THE FRONTAL BOUNDARY. MIN TEMPS TO RANGE FROM THE LWR TO MID 30S NEAR THE MI BORDER...TO THE LWR TO MID 40 SOUTH. MODELS SEEM CONVINCED NOW THAT THE STALLED BOUNDARY WL BEGIN TO STEADILY LIFT NORTH AS A WRMFNT ON TUE IN RESPONSE TO A SIGNIFICANT SHORTWAVE TROF MOVING NEWD THRU THE SRN ROCKIES. THE FNT IS EXPECTED TO STRETCH ROUGHLY FROM SRN MN E-SE THRU THE WI/IL BORDER BY 00Z WED WITH CONVERGENCE ALONG THE FNT/GULF MOISTURE LIFTING OVER THE FNT LEADING TO MORE SHWR/TSTM ACTIVITY. MAY NEED TO BRING POPS NORTH A TIER OF COUNTIES...LEAVING ONLY FAR NRN WI DRY THRU THE DAYLIGHT HOURS. MORE CLOUDS/HIGHER POPS WL LEAD TO A COOLER DAY WITH MAX TEMPS RANGING FROM THE LWR 60S SOUTH (COOLER LAKESIDE)...TO NEAR 70 DEGS ALONG THE MI BORDER. CHC OF SHWRS/TSTMS WL CONT ACROSS NE WI TUE NGT AS THE WRMFNT SLOWLY LIFTS NORTH INTO SRN WI. AS THE SHORTWAVE TROF MOVES TOWARD THE CNTRL PLAINS ON WED...THE WRMFNT WL CONT TO LIFT NWD THRU WI AND ESSENTIALLY BE NORTH OF THE FCST AREA BY LATE WED. ANTICIPATE AT LEAST A CHC OF SHWRS/TSTMS TO ACCOMPANY THE WRMFNT...BUT BELIEVE THE PCPN WL HAVE A TENDENCY OF BECOMING MORE ISOLATED IN NATURE ACROSS CNTRL/E-CNTRL WI WED AFTERNOON AS THE MAIN FOCUS SHIFTS NORTH WITH THE FNT AND THERE IS A LACK OF ANY TRIGGER IN THE SOUTH. WED WL FEEL MORE LIKE A SUMMER DAY WITH MAX TEMPS RANGING FROM AROUND 70 DEGS NORTH...UPR 70S CNTRL WI (COOLER NEAR LAKE MI) AND DEW POINTS CLIMBING INTO THE 50S. THE SHORTWAVE TROF IS PROGGED TO MOVE THRU THE CNTRL PLAINS WED NGT AND BEGIN TO WEAKEN IN THE PROCESS. BY THU...WHAT IS LEFT OF THE TROF WL REACH THE UPR MS VALLEY WITH A CDFNT EXTENDED SW THRU THE CNTRL PLAINS. PCPN CHCS APPEAR MINIMAL WED NGT INTO THU MORNING...HOWEVER AS BETTER MID-LEVEL FORCING/INCREASING INSTABILITY BECOME MORE PREVALENT THU AFTERNOON...PCPN CHCS LOOK TO BE ON THE INCREASE ONCE AGAIN. GUSTY SOUTH WINDS ON THU WL CONT TO PUMP GULF MOISTURE INTO WI WITH DEW POINTS EXPECTED TO BE IN THE MID TO UPR 50S. COMBINE THESE DEW POINTS WITH MAX TEMPS IN THE 75-80 DEG RANGE (AWAY FROM LAKE MI) AND WE WL HAVE A SUMMER FEEL TO THE AIR MASS. PCPN CHCS WL CONT THU NGT AS STRONGER WAA SURGES THRU WI AHEAD OF THE ADVANCING CDFNT. THIS CDFNT IS FCST TO PUSH INTO WI ON FRI AND SET THE STAGE FOR ADDITIONAL SHWRS/TSTMS. TOO EARLY TO DETERMINE THE STRENGTH OF THESE STORMS...BUT WITH THE MODELS SHOWING LITTLE IN THE WAY OF MID OR UPR SUPPORT...THIS WOULD LIMIT THE SEVERE RISK. MAX TEMPS ON FRI SHOULD BE A FEW DEGS COOLER THAN THU DUE TO THICKER CLOUDS/HIGHER CHC OF PCPN. JUST LIKE ITS PREDECESSOR...THIS CDFNT IS FCST TO SAG SOUTH AND EVENTUALLY STALL SOMEWHERE IN THE VICINITY OF THE WI/IL BORDER NEXT WEEKEND. THE EXACT LOCATION OF THIS BOUNDARY WL ULTIMATELY DETERMINE THE NRN EXTENT OF ANY PCPN IN THE VICINITY OF CNTRL/E-CNTRL WI. FOR THE MOST PART...NRN WI REMAIN DRY NEXT SAT AS HI PRES OVER SRN CANADA FEEDS DRIER AIR INTO NRN SECTIONS OF THE GREAT LAKES. SAT WL ALSO BE COOLER BEHIND THE INITIAL CDFNT WITH MAX TEMPS RANGING ONLY IN THE MID 50S LAKESIDE...TO THE LWR 70S OVER CNTRL WI. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 104 PM CDT SUN MAY 3 2015 CONDITIONS WERE VFR ACROSS THE AREA AT MIDDAY AS A COLD FRONT WAS JUST ENTERING THE NORTHWEST CORNER OF WISCONSIN. CONFIDENCE HAS WANED WITH REGARD TO FORECAST OF CONVECTION ACROSS THE AREA THIS AFTERNOON INTO MONDAY MORNING. ONLY MADE MINOR ADJUSTMENTS TO TIMING FROM THE PREVIOUS FORECAST FOR NOW. THE MOST UNSTABLE CONDITIONS APPEARED TO BE ACROSS NORTH CENTRAL WISCONSIN WHERE MUCAPE VALUES WERE 500+ J/KG WITH LITTLE TO NO CIN THERE...BUT NO CONVECTION WAS YET EVIDENT IN THAT AREA. SHOWERS AND ISOLATED THUNDERSTORMS WERE CONFINED TO MINNESOTA AND EASTERN LAKE SUPERIOR AT 1745Z. MOST OF THE 12Z MODELS SHOWED QPF WITH THE FRONT GREATLY EXPANDING DURING THE AFTERNOON TO COVER THE ENTIRE AREA. A QUICK LOOK AT THE 16Z HRRR INDICATED ISOLATED-SCATTERED LIGHT QPF UNTIL A MORE SOLID AREA OF PRECIPITATION REACHES NORTH CENTRAL WISCONSIN. THIS LOOKS LIKE ITS ON TRACK...AT LEAST RIGHT NOW...SO MAINLY VFR AND DRY THE REST OF THE DAY IF IT REMAINS ON TRACK. CANNOT RULE OUT CONVECTIVE DEVELOPMENT WITH SPC DAY 1 SEVERE OUTLOOK INCLUDING MUCH OF THE AREA IN A SLIGHT RISK FOR SEVERE...WITH POSSIBLE DAMAGING WINDS AND LARGE HAIL THIS AFTERNOON AND TONIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....TDH LONG TERM......KALLAS AVIATION.......MG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1224 PM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 321 AM CDT SUN MAY 3 2015 REGIONAL RADARS THIS MORNING SHOWING SOME CONVECTIVE ACTIVITY OVER CENTRAL AND WESTERN IOWA. THIS IS OCCURRING ON THE NOSE OF THE LOW LEVEL JET AND AHEAD OF A SHORT WAVE TROUGH MOVING ACROSS NORTHERN NEBRASKA. THE 03.03Z RAP INDICATES THIS WAVE WILL CONTINUE TO TRACK EASTWARD ACROSS NORTHERN IOWA THROUGH THE MORNING WITH THE LOW LEVEL JET VEERING TO THE EAST TO REMAIN AHEAD OF THE WAVE. THE RAP...03.04Z HRRR AND THE 03.00Z HI-RES ARW AND NMM ALL SUGGEST THERE IS A CHANCE THAT SOME OF THE ACTIVITY WITH THIS WAVE COULD GET INTO NORTHEAST IOWA AND SOUTHWEST WISCONSIN AND HAVE ADDED IN A SMALL CHANCE FOR THIS THROUGH ABOUT THE MIDDLE OF THE MORNING. THE MAIN CONVECTIVE SHOW WILL COME LATE THIS AFTERNOON INTO THE EVENING. THE 03.00Z MODELS HAVE REMAIN FAIRLY CONSISTENT TAKING THE MAIN SHORT WAVE TROUGH...CURRENTLY OVER SASKATCHEWAN...ALMOST DUE EAST WITH A SLIGHT POSITIVE TILT AND THE PV ADVECTION IN THE 500-300 MB LAYER REMAINING NORTH OF THE AREA. AS THIS WAVE MOVES EAST...IT WILL PUSH A COLD FRONT INTO THE AREA LATE THIS AFTERNOON AND THEN ACROSS THE REGION TONIGHT. BUFKIT SOUNDINGS FROM THE 03.00Z NAM INDICATE A PRETTY DEEP MIXED LAYER...UP TO ABOUT 850 MB...AHEAD OF THE FRONT THAT COULD BRING DOWN SOME DRIER AIR AND KEEP THE DEW POINTS CAPPED IN THE MID 50S. WITH 925 MB TEMPERATURES RISING ABOUT 2 TO 3C OVER SATURDAY...EXPECT THE SURFACE TEMPERATURES TO BE WARMER THAN SATURDAY WITH MIDDLE 80S FOR MUCH OF THE AREA. THE COMBINATION OF THESE TEMPS AND DEW POINTS SHOULD YIELD ML CAPES AROUND 1500 J/KG OR SO ALONG AND AHEAD OF THE FRONT. THE FORECAST SOUNDINGS ALSO SHOW A WEAK CAP IN THE WARM SECTOR AHEAD OF THE FRONT AND WITH MINIMAL HEIGHT FALLS...IT WILL TAKE THE THERMODYNAMIC FORCING WITH THE FRONT TO BREAK THE CAP. THE FRONTOGENESIS WITH THE FRONT LOOKS TO BE MODERATE IN STRENGTH IN THE 1000-850 MB AND THEN WEAK FROM 850 MB UP THROUGH 500 MB. THIS SHOULD BE ENOUGH TO BREAK THE WEAK CAP AND ALLOW CONVECTION TO FORM ALONG THE FRONT. THERE IS GOOD CLUSTERING AMONG THE HI-RES MESO MODELS...THE 03.00Z NAM12 AND 03.00Z NESTED NAM THAT THE FRONT SHOULD START TO APPROACH LATE THIS AFTERNOON WITH THE CONVECTION FIRST IMPACTING THE NORTHERN PARTS OF THE AREA IN THE 21Z-24Z WINDOW AND THEN DEVELOPING SOUTHWEST ALONG THE FRONT VERY LATE IN THE AFTERNOON INTO THE EARLY EVENING. THIS ACTIVITY SHOULD REMAIN STRONG INTO THE MIDDLE OF THE EVENING BEFORE THE CAPE QUICKLY DWINDLES WITH JUST GENERAL CONVECTION EXPECTED FOR CENTRAL AND SOUTHWEST WISCONSIN. THE SEVERE THREAT IS STILL PRESENT FROM ABOUT 4 PM THROUGH 10 PM WITH LARGE HAIL LOOKING TO BE THE MAIN THREAT AS GOOD MID LEVEL LAPSE RATES SHOULD AID IN THE HAIL PRODUCTION. NOT EXPECTING THE HAIL TO BE OVERLY LARGE AS A GENERAL LACK OF SHEAR WILL KEEP THE UPDRAFT ROTATION SUBDUED. WHAT SHEAR THERE IS WILL BE IN THE 0-3KM LAYER AND IS EXPECTED TO BE ON THE ORDER OF 25 TO 30 KNOTS...WHICH SHOULD BE ENOUGH TO PRODUCE SOME WIND GUSTS BUT MAY NOT BE ENOUGH TO KEEP THE GUST FRONTS CLOSE TO THE STORMS. THE MODELS NOW SUGGEST THE FRONT MAY NOT PUSH AS FAR SOUTH AS PREVIOUSLY INDICATED BEFORE STALLING OUT MONDAY. THE GENERAL MODEL CONSENSUS NOW SHOWS THE FRONT STALLING OVER SOUTHERN IOWA INSTEAD OF NORTHERN MISSOURI. THIS CLOSER PROXIMITY TO THE AREA COULD ALLOW SOME OF THE SHOWERS AND STORMS EXPECTED TO OCCUR NORTH OF THE FRONT TO CONTINUE OVER NORTHEAST IOWA INTO SOUTHWEST WISCONSIN MONDAY AFTERNOON AND EVENING. THE UPPER LEVEL PATTERN WILL START TO SHIFT TO MORE OF A SOUTHWEST FLOW AND BEGIN TO PUSH THE FRONT BACK TO THE NORTH LATE MONDAY NIGHT RESULTING IN A NORTHWARD EXPANSION OF THE RAIN CHANCES OVER ALL OF SOUTHEAST MINNESOTA AND MUCH OF WESTERN AND CENTRAL WISCONSIN. MOST OF THE AREA WILL THEN HAVE A CHANCE FOR RAIN TUESDAY AS THE FRONT MOVES BACK INTO THE AREA AND COULD POSSIBLY BE ACCOMPANIED BY A SHORT WAVE TROUGH ALOFT IN THE SOUTHWEST FLOW. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 321 AM CDT SUN MAY 3 2015 THE SOUTHWEST FLOW ALOFT LOOKS TO CONTINUE THROUGH THE PERIOD AS THE MAIN RIDGE REMAINS OVER THE EASTERN CONUS AND A LARGE UPPER LEVEL LOW SINKS SLOWLY SOUTH OVER THE WESTERN CONUS. WITH THIS FLOW PATTERN...SEVERAL PIECES OF ENERGY ARE EXPECTED TO COME OUT AND ACROSS THE UPPER MIDWEST. IT LOOKS AS IF IT WILL TAKE UNTIL SOMETIME WEDNESDAY OR WEDNESDAY NIGHT FOR THE RETREATING FRONT TO GET NORTH OF THE AREA. ONCE THIS HAPPENS...A COLD FRONT AND SURFACE LOW PRESSURE WILL START TO APPROACH FROM THE WEST WITH WHAT SHOULD BE A STRONGER SHORT WAVE TROUGH ALOFT. THIS FRONT WILL THEN MOVE ACROSS THE AREA IN THE END OF THE WORK WEEK WITH IT POSSIBLY BECOME STALLED OUT JUST TO THE SOUTH OF THE AREA INTO THE START OF THE WEEKEND. WITH THIS MESSY PATTERN...WILL CARRY RAIN CHANCES EACH DAY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A DRY PERIOD OR TWO...ESPECIALLY ONCE THE RETURNING FRONT GETS PAST THE AREA. HOWEVER...CONFIDENCE ON THIS IS TOO LOW TO WORK INTO THE FORECAST AT THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1224 PM CDT SUN MAY 3 2015 VFR CONDITIONS EXPECTED THROUGH THIS AFTERNOON BEFORE A COLD FRONT ENTERS THE AREA EARLY THIS EVENING. EXPECTING A LINE OF THUNDERSTORMS TO ACCOMPANY THE FRONT...MAKING PASSAGE THROUGH KRST IN THE 23Z-03Z TIME FRAME...AND IN THE 01Z-05Z TIME FRAME AT KLSE. EXPECT DETERIORATING CONDITIONS WITH THE SHRA/TS ACTIVITY WITH CIGS/VSBY TEMPORARILY DIPPING INTO THE MVFR/IFR RANGE. THERE REMAINS THE POSSIBILITY THAT A FEW OF THE STORMS WILL BE CAPABLE OF PRODUCING STRONG GUSTY WINDS IN EXCESS OF 50KT AND HAIL TO THE SIZE OF QUARTERS. LOOK FOR THE FRONT AND SHRA/TS ACTIVITY TO CLEAR SOUTHEAST OF THE AREA IN THE 07-09Z TIME FRAME WITH A RETURN TO VFR CONDITIONS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 AM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 321 AM CDT SUN MAY 3 2015 REGIONAL RADARS THIS MORNING SHOWING SOME CONVECTIVE ACTIVITY OVER CENTRAL AND WESTERN IOWA. THIS IS OCCURRING ON THE NOSE OF THE LOW LEVEL JET AND AHEAD OF A SHORT WAVE TROUGH MOVING ACROSS NORTHERN NEBRASKA. THE 03.03Z RAP INDICATES THIS WAVE WILL CONTINUE TO TRACK EASTWARD ACROSS NORTHERN IOWA THROUGH THE MORNING WITH THE LOW LEVEL JET VEERING TO THE EAST TO REMAIN AHEAD OF THE WAVE. THE RAP...03.04Z HRRR AND THE 03.00Z HI-RES ARW AND NMM ALL SUGGEST THERE IS A CHANCE THAT SOME OF THE ACTIVITY WITH THIS WAVE COULD GET INTO NORTHEAST IOWA AND SOUTHWEST WISCONSIN AND HAVE ADDED IN A SMALL CHANCE FOR THIS THROUGH ABOUT THE MIDDLE OF THE MORNING. THE MAIN CONVECTIVE SHOW WILL COME LATE THIS AFTERNOON INTO THE EVENING. THE 03.00Z MODELS HAVE REMAIN FAIRLY CONSISTENT TAKING THE MAIN SHORT WAVE TROUGH...CURRENTLY OVER SASKATCHEWAN...ALMOST DUE EAST WITH A SLIGHT POSITIVE TILT AND THE PV ADVECTION IN THE 500-300 MB LAYER REMAINING NORTH OF THE AREA. AS THIS WAVE MOVES EAST...IT WILL PUSH A COLD FRONT INTO THE AREA LATE THIS AFTERNOON AND THEN ACROSS THE REGION TONIGHT. BUFKIT SOUNDINGS FROM THE 03.00Z NAM INDICATE A PRETTY DEEP MIXED LAYER...UP TO ABOUT 850 MB...AHEAD OF THE FRONT THAT COULD BRING DOWN SOME DRIER AIR AND KEEP THE DEW POINTS CAPPED IN THE MID 50S. WITH 925 MB TEMPERATURES RISING ABOUT 2 TO 3C OVER SATURDAY...EXPECT THE SURFACE TEMPERATURES TO BE WARMER THAN SATURDAY WITH MIDDLE 80S FOR MUCH OF THE AREA. THE COMBINATION OF THESE TEMPS AND DEW POINTS SHOULD YIELD ML CAPES AROUND 1500 J/KG OR SO ALONG AND AHEAD OF THE FRONT. THE FORECAST SOUNDINGS ALSO SHOW A WEAK CAP IN THE WARM SECTOR AHEAD OF THE FRONT AND WITH MINIMAL HEIGHT FALLS...IT WILL TAKE THE THERMODYNAMIC FORCING WITH THE FRONT TO BREAK THE CAP. THE FRONTOGENESIS WITH THE FRONT LOOKS TO BE MODERATE IN STRENGTH IN THE 1000-850 MB AND THEN WEAK FROM 850 MB UP THROUGH 500 MB. THIS SHOULD BE ENOUGH TO BREAK THE WEAK CAP AND ALLOW CONVECTION TO FORM ALONG THE FRONT. THERE IS GOOD CLUSTERING AMONG THE HI-RES MESO MODELS...THE 03.00Z NAM12 AND 03.00Z NESTED NAM THAT THE FRONT SHOULD START TO APPROACH LATE THIS AFTERNOON WITH THE CONVECTION FIRST IMPACTING THE NORTHERN PARTS OF THE AREA IN THE 21Z-24Z WINDOW AND THEN DEVELOPING SOUTHWEST ALONG THE FRONT VERY LATE IN THE AFTERNOON INTO THE EARLY EVENING. THIS ACTIVITY SHOULD REMAIN STRONG INTO THE MIDDLE OF THE EVENING BEFORE THE CAPE QUICKLY DWINDLES WITH JUST GENERAL CONVECTION EXPECTED FOR CENTRAL AND SOUTHWEST WISCONSIN. THE SEVERE THREAT IS STILL PRESENT FROM ABOUT 4 PM THROUGH 10 PM WITH LARGE HAIL LOOKING TO BE THE MAIN THREAT AS GOOD MID LEVEL LAPSE RATES SHOULD AID IN THE HAIL PRODUCTION. NOT EXPECTING THE HAIL TO BE OVERLY LARGE AS A GENERAL LACK OF SHEAR WILL KEEP THE UPDRAFT ROTATION SUBDUED. WHAT SHEAR THERE IS WILL BE IN THE 0-3KM LAYER AND IS EXPECTED TO BE ON THE ORDER OF 25 TO 30 KNOTS...WHICH SHOULD BE ENOUGH TO PRODUCE SOME WIND GUSTS BUT MAY NOT BE ENOUGH TO KEEP THE GUST FRONTS CLOSE TO THE STORMS. THE MODELS NOW SUGGEST THE FRONT MAY NOT PUSH AS FAR SOUTH AS PREVIOUSLY INDICATED BEFORE STALLING OUT MONDAY. THE GENERAL MODEL CONSENSUS NOW SHOWS THE FRONT STALLING OVER SOUTHERN IOWA INSTEAD OF NORTHERN MISSOURI. THIS CLOSER PROXIMITY TO THE AREA COULD ALLOW SOME OF THE SHOWERS AND STORMS EXPECTED TO OCCUR NORTH OF THE FRONT TO CONTINUE OVER NORTHEAST IOWA INTO SOUTHWEST WISCONSIN MONDAY AFTERNOON AND EVENING. THE UPPER LEVEL PATTERN WILL START TO SHIFT TO MORE OF A SOUTHWEST FLOW AND BEGIN TO PUSH THE FRONT BACK TO THE NORTH LATE MONDAY NIGHT RESULTING IN A NORTHWARD EXPANSION OF THE RAIN CHANCES OVER ALL OF SOUTHEAST MINNESOTA AND MUCH OF WESTERN AND CENTRAL WISCONSIN. MOST OF THE AREA WILL THEN HAVE A CHANCE FOR RAIN TUESDAY AS THE FRONT MOVES BACK INTO THE AREA AND COULD POSSIBLY BE ACCOMPANIED BY A SHORT WAVE TROUGH ALOFT IN THE SOUTHWEST FLOW. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 321 AM CDT SUN MAY 3 2015 THE SOUTHWEST FLOW ALOFT LOOKS TO CONTINUE THROUGH THE PERIOD AS THE MAIN RIDGE REMAINS OVER THE EASTERN CONUS AND A LARGE UPPER LEVEL LOW SINKS SLOWLY SOUTH OVER THE WESTERN CONUS. WITH THIS FLOW PATTERN...SEVERAL PIECES OF ENERGY ARE EXPECTED TO COME OUT AND ACROSS THE UPPER MIDWEST. IT LOOKS AS IF IT WILL TAKE UNTIL SOMETIME WEDNESDAY OR WEDNESDAY NIGHT FOR THE RETREATING FRONT TO GET NORTH OF THE AREA. ONCE THIS HAPPENS...A COLD FRONT AND SURFACE LOW PRESSURE WILL START TO APPROACH FROM THE WEST WITH WHAT SHOULD BE A STRONGER SHORT WAVE TROUGH ALOFT. THIS FRONT WILL THEN MOVE ACROSS THE AREA IN THE END OF THE WORK WEEK WITH IT POSSIBLY BECOME STALLED OUT JUST TO THE SOUTH OF THE AREA INTO THE START OF THE WEEKEND. WITH THIS MESSY PATTERN...WILL CARRY RAIN CHANCES EACH DAY...ALTHOUGH WOULD NOT BE SURPRISED TO SEE A DRY PERIOD OR TWO...ESPECIALLY ONCE THE RETURNING FRONT GETS PAST THE AREA. HOWEVER...CONFIDENCE ON THIS IS TOO LOW TO WORK INTO THE FORECAST AT THIS TIME. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 630 AM CDT SUN MAY 3 2015 MAIN AVIATION CONCERNS ARE THUNDERSTORMS AT BOTH RST/LSE TAF SITES LATE THIS AFTERNOON INTO THIS EVENING. LATEST 11Z SURFACE ANALYSIS SHOWS COLD FRONT EXTENDING FROM SOUTHERN ONTARIO INTO SOUTHERN SOUTH DAKOTA. COLD FRONT IS EXPECTED TO PUSH EAST INTO WESTERN WISCONSIN AND SOUTHEAST MINNESOTA LATE THIS AFTERNOON AND EVENING. DUE TO DAYTIME HEATING OUT AHEAD OF THE COLD FRONT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND BEHIND THE FRONT AFTER 21Z TODAY. THE LATEST MODEL TRENDS HAVE SLOWED THE PROGRESSION OF THE FRONT/DEVELOPMENT OF CONVECTION AND HAVE DELAYED THE ONSET OF CONVECTION AT THE RST/LSE TAF SITES BEGINNING AROUND 00Z AT RST AND 01Z LSE. COLD FRONT...AND ASSOCIATED CONVECTION...WILL MOVE SOUTH OF THE TAF SITES BY 04-06Z MONDAY. FEW OF THE THUNDERSTORMS MAY BECOME SEVERE...HOWEVER CONFIDENCE IN THE EXACT PLACEMENT/LOCATION OF ANY SEVERE THUNDERSTORMS IS LOW. WIND GUST OF UP TO 60 MPH AND LARGE HAIL ARE POSSIBLE WITH THE THUNDERSTORMS FROM 21Z TODAY TO 04Z MONDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1213 PM MDT SUN MAY 3 2015 .UPDATE... ISSUED AT 1156 AM MDT SUN MAY 3 2015 CLOUDS ARE ALREADY STARTING TO INCREASE ACROSS MUCH OF THE AREA PER RECENT WATER VAPOR SATELLITE IMAGERY. POTENTIAL FOR SHOWERS AND THUNDERSTORMS LIKELY TO INCREASE CONSIDERABLY OVER THE NEXT FEW HOURS...ESPECIALLY ALONG/EAST OF THE LARAMIE RANGE. A WEAK SURFACE BOUNDARY WAS EVIDENT NORTHEAST OF CHEYENNE ON THE 18Z RADAR LOOP. AS THIS FEATURE SHIFTS SOUTHWEST...HIGH-RES MODELS TURN LLVL WINDS NORTHEAST AND UPSLOPE BY 18-19Z. THIS IS ALREADY REFLECTED IN SURFACE OBS OVER WESTERN NE. THE LAST COUPLE RUNS OF THE HRRR HAVE BEEN CONSISTENT WITH SHOWERS/TSTMS BECOMING FAIRLY WIDESPREAD AFTER 21Z OVER FAR SOUTHEAST WY...SO DECIDED TO BUMP POPS UP TO CATEGORICAL. ONLY OTHER CHANGE WAS TO INCREASE HIGHS A FEW DEGREES OVER THE PLAINS. WE ARE ALREADY 67F IN CHEYENNE AT NOON. ANOTHER DEGREE OR TWO OF WARMING IS POSSIBLE BEFORE CLOUDS AND PCPN HELP TO COOL THINGS DOWN. && .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 300 AM MDT SUN MAY 3 2015 STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY 18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS CONTINUES OVER THE DESERT SOUTHWEST. BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST. A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR -4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA. LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL THIS AFTERNOON. SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD UPSLOPING WINDS. SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 300 AM MDT SUN MAY 3 2015 THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD. ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA. GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS). && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1213 PM MDT SUN MAY 3 2015 CONCERNS ARE TWO-FOLD FOR THIS TAF CYCLE. THE INITIAL CONCERN WILL BE DEVELOPING CONVECTION NR KRWL AND KLAR AND PROBABLY GETTING INTO KCYS AFTER 20Z. FAVORED VCTS AT ALL THESE SITES UNTIL INDIVIDUAL CELLS CAN BE IDENTIFIED AND TIMED. PANHANDLE SITES WILL SEE LESS OF A CHANCE TO SEE THIS THUNDERSTORM ACTIVITY...ALTHOUGH KBFF MAY GET INTO IT AFTER 22Z. LATEST MODELS SUGGEST THIS ACTIVITY WILL LINGER INTO THE OVERNIGHT AND MORNING HOURS AS WELL AND EXPECT AVIATION CONDITIONS TO WORSEN AFTER 03-06Z AS WINDS TURN UPSLOPE FLOPPING AROUND TO THE SOUTHEAST. THIS IS A FAVORABLE DIRECTION FOR THE DEVELOPMENT OF LOW STRATUS/FG. ALSO EXPECT ANOTHER BAND OF SHOWERS TO LIFT NORTH ACROSS PRIMARILY PANHANDLE SITES AFTER 06Z. ANY STRATUS OR FOG THAT DOES EXIST WILL LIKELY LIFT IF THESE SHOWERS MATERIALIZE. FOR NOW HAVE TRENDED CONDITIONS DOWNWARD AFTER 06Z TO ACCOUNT FOR THIS ACTIVITY. && .FIRE WEATHER... ISSUED AT 300 AM MDT SUN MAY 3 2015 DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...CLH SHORT TERM...GCC LONG TERM...ZF AVIATION...CAH FIRE WEATHER...GCC
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
400 AM CDT TUE MAY 5 2015 .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * RAIN CONTINUES THROUGH THE MORNING. A FEW CLAPS OF THUNDER ARE NOT OUT OF THE QUESTION THROUGH DAYBREAK. * EAST WINDS INCREASE TO 10-11 KT THIS MORNING AND AFTERNOON. * IFR CIGS ARE EXPECTED BY 12Z AND NOT EXPECTING CIGS TO LIFT TO MVFR UNTIL THIS EVENING IF NOT LATER. * ANOTHER CHANCE OF SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN. JEE //DISCUSSION...UPDATED 06Z... THE MESSY PATTERN CONTINUES. A SWATH OF SHOWERS AND A FEW THUNDERSTORMS ARE SLOWLY PUSHING NORTHEAST AND WILL IMPACT ALL OF THE TERMINALS. LIGHTNING STRIKES ARE FEW AND FAR BTWN SO KEPT VCTS GOING THROUGH 12Z. IT IS STILL RATHER DRY OUT THERE DESPITE THE RAIN...SO MVFR CIGS ARE ADVANCING SLOWLY. ALL GUIDANCE MEMBERS INDICATE THE IFR CIGS TO OUR WEST WILL INFILTRATE THE TERMINALS EARLY THIS MORNING. THE FRONT CURRENTLY OVER CENTRAL IL WILL REMAIN SOUTH OF THE TERMINALS TODAY...WHICH SHOULD ME WE ARE LOCKED INTO IFR CIGS UNTIL THE FRONT LIFTS NORTH WEDNESDAY MORNING. WINDS WILL BE OUT OF THE EAST AS WELL. GUIDANCE ALSO HINTS AT ANOTHER ROUND OF SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTERNOON SO PUT A PROB30 IN AS CONFIDENCE IS NOT OVERLY HIGH GIVEN HOW MESSY THE PATTERN IS. JEE //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN SHOWERS THROUGH THIS MORNING AND ONLY A FEW LIGHTNING STRIKES THROUGH DAYBREAK. MEDIUM-LOW CONFIDENCE IN OCCURRENCE AND COVERAGE OF -SHRA AND TSRA THIS AFTN. * MEDIUM-HIGH CONFIDENCE IN VSBY...STRONGER DOWNPOURS COULD LOWER VSBY TO 2SM. * MEDIUM-HIGH CONFIDENCE IN CIGS DROPPING TO IFR THIS MORNING. MEDIUM CONFIDENCE IN CIGS LIFTING TO MVFR THIS EVENING AS THEY COULD REMAIN IFR OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...SLIGHT CHANCE TSRA. MAINLY VFR. SOUTHEAST WINDS. THURSDAY...VFR. SOUTH WINDS. FRIDAY...CHANCE TSRA. MAINLY VFR. SOUTH WINDS. SATURDAY...CHANCE OF TSRA WITH BRIEF MVFR...THOUGH MAINLY VFR. SOUTHWEST WINDS BECOMING EAST-NORTHEAST. SUNDAY...CHANCE OF TSRA. BRIEF MVFR POSSIBLE. SOUTHEAST WINDS. RATZER && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
333 AM CDT TUE MAY 5 2015 .SHORT TERM...(TODAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 A FRONTAL BOUNDARY IS ORIENTED WEST-EAST ACROSS CENTRAL IL THIS MORNING WITH PRECIPITATION IN ISENTROPIC ASCENT REGION LARGELY TO THE NORTH OF THE BOUNDARY. MODELS INDICATE THE BOUNDARY AND PRECIPITATION WILL SHIFT SLOWLY NORTHWARD TODAY. WEAK DISTURBANCES MOVING ALONG THE BOUNDARY WILL PRODUCE SOME ENHANCEMENTS IN CONVECTIVE SHOWER COVERAGE IN THE VICINITY...EARLY THIS MORNING FROM AROUND THE ILLINOIS RIVER NORTHWESTWARD...AND LATE IN THE AFTERNOON NORTH OF THE I-74 CORRIDOR. FOR THE MOST PART...CONVECTION SHOULD BE WEAK AT THIS POINT WITH ONLY WEAK MID-LEVEL INSTABILITY REMAINING THROUGH THE NIGHT...AND 0-6KM BULK SHEAR UP TO 25-30 KTS THIS MORNING DIMINISHING SUBSTANTIALLY FOR THE AFTERNOON. 1000-1500 JOULES OF SURFACE-BASED CAPE SHOULD BE ABLE TO DEVELOP WITH AFTERNOON HEATING ALONG/NORTH OF I-72 AND CAN`T RULE OUT ISOLATED THUNDERSTORMS SOUTHWARD TO I-72 AS A RESULT. && .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 ONGOING CONVECTION ALONG THE BOUNDARY OVER NORTHERN ILLINOIS THIS MORNING NOT ONLY DRIVING THE WEATHER THROUGHOUT THE DAY, BUT INTO THE OVERNIGHT AS WELL. GFS AND NAM CONTINUE TO KEEP A BIT OF PRECIP PRETTY FAR SOUTH, AS FAR SOUTH AS A LINE FROM HAVANA TO BLOOMINGTON. HOWEVER, THE RAP/RUC AND THE HRRR ARE PUSHING THE AREA OF CONVECTION WELL TO THE NORTH THROUGH THE MORNING WITH THE BOUNDARY. WHEN THE SECONDARY WAVE RIPPLES THROUGH THE REGION AFTER 00Z, IT WOULD BE DISPLACED NORTH OF THE FA. THE 4KM WRF HAS JUST THAT SOLUTION, STARTING MORE IN LINE WITH THE RAP/RUC AND HRRR...AND KEEPING THE FA DRY AFTER 00Z, BUT A LITTLE MORE GENEROUS WITH SOME ISOLATED INSTABILITY SHOWERS. HAVE KEPT ISO TS IN THE NORTH, MAINLY ALONG AND NORTH OF I-74 FOR THE EARLY EVENING. HIGH PRESSURE BEGINS TO BUILD BACK INTO THE REGION LATER TONIGHT, SOUTHERLY WINDS PUSHING THE FRONT BACK TO THE NORTH AND OUT OF THE FORECAST AREA THROUGH WED NIGHT. FORECAST REMAINS ROUGHLY THE SAME BEYOND DAY 3... PRECIP CHANCES SLOWLY EDGING BACK INTO WEST CENTRAL ILLINOIS FOR THURSDAY AS AN UPPER LEVEL WAVE PUSHES OUT OF THE SW. THE ENERGY IS PART OF A GENERAL PATTERN SHIFT TO MORE SOUTHWESTERLY FLOW WITH THE UPPER LEVEL TROF DIGGING BACK IN OVER THE SWRN CONUS. THE SFC LOW MOVES OUT INTO THE UPPER MIDWEST AND INTO CANADA BY THE END OF THE WEEK, BUT IN SHIFTING TO MORE SOUTHWESTERLY FLOW ALOFT, OPENS THE DOOR TO A SERIES OF SHORTWAVES THAT KEEP THE FORECAST WET FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND. TEMPS RATHER WARM THROUGH THE FORECAST WITH OVERCAST AND RAINY SKIES KEEPING THE OVERNIGHT LOWS UP A BIT, BUT LIKELY NOT NEARLY AS WARM AS THE TREND IN THE GUIDANCE. HAVE KNOCKED THEM DOWN A COUPLE DEGREES. SOUTHERLY FLOW AND A RELATIVELY WARM AIRMASS KEEPING THE HIGHS A BIT ABOVE NORMS, EVEN WITH THE PASSAGE OF THE FIRST LOW SKIRTING TO THE NW...THE MID LEVELS REMAIN WARM UNTIL THE MAIN TROF OVER THE SW LIFTS INTO AND OUT OF THE GREAT LAKES. COOLER AIR IN THE MIDLEVELS IS ONLY AROUND FOR 36 HOURS DAY 7/8 BEFORE THE WARM AIRMASS REESTABLISHES ITSELF. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1144 PM CDT MON MAY 4 2015 FAIRLY SMALL AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS IS STILL MAKING ITS WAY ACROSS CENTRAL ILLINOIS, AND THIS AREA IS ONLY A THREAT AT KBMI AND KCMI FOR A FEW MORE HOURS. MORE WIDESPREAD SHOWERS/STORMS ARE UPSTREAM FROM THE CENTRAL ILLINOIS TERMINAL AREA. RECENT SHORT RANGE/HIGH RESOLUTION MODEL GUIDANCE, SUPPORTED BY RADAR LOOPS, SUGGESTS THAT MUCH OF THIS PRECIPITATION WILL PASS TO THE NORTH OF THE LOCAL TERMINALS. KPIA AND KBMI STAND THE BEST CHANCE OF BEING IMPACTED BY THIS UPSTREAM PRECIPITATION FOR SEVERAL MORE HOURS, WHILE KSPI, KDEC, AND KCMI WILL BE MOSTLY DRY. OUTSIDE OF ANY APPRECIABLE RAINFALL AREAS, WHICH WILL BRIEFLY PRODUCE MVFR CONDITIONS, VFR CONDITIONS SHOULD PREVAIL. MOST OF THE REST OF THE NIGHT SHOULD SEE VARIABLE WINDS WITH A NEARLY STATIONARY BOUNDARY IN THE VICINITY. EXPECT WINDS TO TREND SOUTHWESTERLY TUESDAY MORNING AS THE FRONT SHIFTS BACK NORTH. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ONTON LONG TERM...HJS AVIATION...BAK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
332 AM CDT TUE MAY 5 2015 .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * -SHRA IS MOVING IN AND WILL PERSIST THROUGH THE MORNING. A FEW CLAPS OF THUNDER ARE NOT OUT OF THE QUESTION THROUGH DAYBREAK. * EAST WINDS INCREASE TO 10-11 KT THIS MORNING AND AFTERNOON. * IFR CIGS ARE EXPECTED BY 12Z AND NOT EXPECTING CIGS TO LIFT TO MVFR UNTIL THIS EVENING IF NOT LATER. * ANOTHER CHANCE OF SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN. JEE //DISCUSSION...UPDATED 06Z... THE MESSY PATTERN CONTINUES. A SWATH OF SHOWERS AND A FEW THUNDERSTORMS ARE SLOWLY PUSHING NORTHEAST AND WILL IMPACT ALL OF THE TERMINALS. LIGHTNING STRIKES ARE FEW AND FAR BTWN SO KEPT VCTS GOING THROUGH 12Z. IT IS STILL RATHER DRY OUT THERE DESPITE THE RAIN...SO MVFR CIGS ARE ADVANCING SLOWLY. ALL GUIDANCE MEMBERS INDICATE THE IFR CIGS TO OUR WEST WILL INFILTRATE THE TERMINALS EARLY THIS MORNING. THE FRONT CURRENTLY OVER CENTRAL IL WILL REMAIN SOUTH OF THE TERMINALS TODAY...WHICH SHOULD ME WE ARE LOCKED INTO IFR CIGS UNTIL THE FRONT LIFTS NORTH WEDNESDAY MORNING. WINDS WILL BE OUT OF THE EAST AS WELL. GUIDANCE ALSO HINTS AT ANOTHER ROUND OF SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTERNOON SO PUT A PROB30 IN AS CONFIDENCE IS NOT OVERLY HIGH GIVEN HOW MESSY THE PATTERN IS. JEE //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN SHOWERS THROUGH THIS MORNING AND ONLY A FEW LIGHTNING STRIKES THROUGH DAYBREAK. MEDIUM-LOW CONFIDENCE IN OCCURRENCE AND COVERAGE OF -SHRA AND TSRA THIS AFTN. * MEDIUM-HIGH CONFIDENCE IN VSBY...STRONGER DOWNPOURS COULD LOWER CIGS TO 2SM. * MEDIUM-HIGH CONFIDENCE IN CIGS DROPPING TO IFR THIS MORNING. MEDIUM CONFIDENCE IN CIGS LIFTING TO MVFR THIS EVENING AS THEY COULD REMAIN IFR OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...SLIGHT CHANCE TSRA. MAINLY VFR. SOUTHEAST WINDS. THURSDAY...VFR. SOUTH WINDS. FRIDAY...CHANCE TSRA. MAINLY VFR. SOUTH WINDS. SATURDAY...CHANCE OF TSRA WITH BRIEF MVFR...THOUGH MAINLY VFR. SOUTHWEST WINDS BECOMING EAST-NORTHEAST. SUNDAY...CHANCE OF TSRA. BRIEF MVFR POSSIBLE. SOUTHEAST WINDS. RATZER && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1151 PM CDT MON MAY 4 2015 .UPDATE... ISSUED AT 848 PM CDT MON MAY 4 2015 LATEST SURFACE ANALYSIS HAS A NEARLY STATIONARY FRONTAL BOUNDARY CUTTING WEST TO EAST ACROSS CENTRAL ILLINOIS ROUGHLY FROM QUINCY TO PARIS. THIS BOUNDARY IS FAIRLY WELL DELINEATED BY AN EXPANDING FINE LINE OF SHOWERS AND ISOLATED THUNDERSTORMS. THE PREVIOUS INTENSITY OF THE AREA OF STORMS PUSHING INTO WEST-CENTRAL ILLINOIS HAS FADED WITH THE LOSS OF DIURNAL INSTABILITY WITH THE BULK OF THE STORMS IN OUR VICINITY CURRENTLY OF THE "GARDEN VARIETY". THE BULK OF THE GUIDANCE, ESPECIALLY RECENT RUNS OF MANY HIGH RESOLUTION MODELS, SUGGEST THE BULK OF THE SHOWERS/STORMS THOUGH THE NIGHT WILL EXIST ALONG/NORTH OF THE FRONTAL BOUNDARY. ALSO, A WAVE LIFTING NORTHEAST OUT OF THE PLAINS IS EXPECTED TO HELP PUSH THE FRONT A LITTLE FURTHER NORTH WITH TIME OVERNIGHT. THESE FACTORS WOULD SUGGEST THE BULK OF THE UPSTREAM PRECIPITATION OVER IOWA AND MISSOURI WOULD TRACK NORTH OF MOST OF THE FORECAST AREA. PLAN TO UPDATE FORECAST TO REFINE POPS, MAINLY TO PUSH THE RISK FURTHER NORTH. OTHERWISE, MINOR TWEAKS ARE NEEDED FOR THE LATEST HOURLY TRENDS. && .SHORT TERM...(TONIGHT) ISSUED AT 245 PM CDT MON MAY 4 2015 FRONTAL BOUNDARY EXTENDING FROM SOUTHERN LAKE MICHIGAN TO NORTHERN KANSAS WILL SINK SOUTHWARD...EVENTUALLY STALLING NEAR THE I-72 CORRIDOR LATER THIS EVENING. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE BOUNDARY...WITH MOST MODEL SOLUTIONS SUGGESTING THE GREATEST AREAL COVERAGE OF PRECIP ACROSS THE NORTHERN HALF OF THE KILX CWA. HRRR IS SHOWING WIDELY SCATTERED STORMS DEVELOPING OVER THE NEXT COUPLE OF HOURS...WITH THE CONVECTION BECOMING MORE WIDESPREAD AFTER SUNSET AS A WEAK LOW-LEVEL JET DEVELOPS. HAVE ADJUSTED RAIN CHANCES ACCORDINGLY...WITH LIKELY POPS ALONG/NORTH OF I-72 TAPERING DOWN TO JUST SLIGHT CHANCE ALONG/SOUTH OF I-70. .LONG TERM...(TUESDAY THROUGH MONDAY) ISSUED AT 245 PM CDT MON MAY 4 2015 AN UPPER LEVEL RIDGE IS EXPECTED TO AMPLIFY OVER THE CENTER OF THE NATION STARTING ON TUESDAY WHICH SHOULD PUSH THE BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS NORTH OF THE FORECAST AREA...AT LEAST INTO THURSDAY. SHORTWAVE ENERGY IS THEN FORECAST TO EJECTS NORTH OUT OF THE SOUTHERN PLAINS AND BRING ABOUT A CHANCE FOR MORE SHOWERS AND THUNDERSTORMS...ESPECIALLY ACROSS OUR WEST...THURSDAY NIGHT INTO FRIDAY. A MORE POTENT 500 MB TROF IS THEN FORECAST TO SLOWLY TRACK OUT OF THE ROCKIES DURING THE WEEKEND BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. MOST MODELS TRACK THIS LOW NORTH-NORTHEAST ON SUNDAY SUGGESTING THE MORE SIGNIFICANT LIFT TO REMAIN WEST OF OUR AREA UNTIL LATE SUNDAY OR MONDAY OF NEXT WEEK WHEN THE SYSTEM WILL SWING A COLD FRONT THROUGH CENTRAL ILLINOIS. UNTIL THEN...WARM TEMPERATURES TO PREVAIL WITH THE SHOWER AND STORM CHANCES ACROSS THE FAR NORTH TOMORROW AS THE FRONT RETREATS BACK TO THE NORTH...AND THEN RAIN CHANCES RETURN LATE THU INTO FRIDAY AND HOLDS THROUGH EARLY NEXT WEEK BEFORE WE FINALLY GET A CHANGE IN AIR MASS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1144 PM CDT MON MAY 4 2015 FAIRLY SMALL AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS IS STILL MAKING ITS WAY ACROSS CENTRAL ILLINOIS, AND THIS AREA IS ONLY A THREAT AT KBMI AND KCMI FOR A FEW MORE HOURS. MORE WIDESPREAD SHOWERS/STORMS ARE UPSTREAM FROM THE CENTRAL ILLINOIS TERMINAL AREA. RECENT SHORT RANGE/HIGH RESOLUTION MODEL GUIDANCE, SUPPORTED BY RADAR LOOPS, SUGGESTS THAT MUCH OF THIS PRECIPITATION WILL PASS TO THE NORTH OF THE LOCAL TERMINALS. KPIA AND KBMI STAND THE BEST CHANCE OF BEING IMPACTED BY THIS UPSTREAM PRECIPITATION FOR SEVERAL MORE HOURS, WHILE KSPI, KDEC, AND KCMI WILL BE MOSTLY DRY. OUTSIDE OF ANY APPRECIABLE RAINFALL AREAS, WHICH WILL BRIEFLY PRODUCE MVFR CONDITIONS, VFR CONDTIONS SHOULD PREVAIL. MOST OF THE REST OF THE NIGHT SHOULD SEE VARIABLE WINDS WITH A NEARLY STATIONARY BOUNDARY IN THE VICINITY. EXPECT WINDS TO TREND SOUTHWESTERLY TUESDAY MORNING AS THE FRONT SHIFTS BACK NORTH. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BAK SHORT TERM...BARNES LONG TERM...SMITH AVIATION...BAK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
228 AM MDT TUE MAY 5 2015 .UPDATE... ISSUED AT 1023 PM MDT MON MAY 4 2015 UPDATED FORECAST TO REFLECT THE DIMINISHED CHANCES FOR RAINFALL FOR THE WESTERN HALF OR SO OF THE AREA THROUGH THE REST OF THE NIGHT. WAS VERY CONFIDENT EARLIER THAT THE LINE OF STORMS WOULD MOVE ACROSS THE ENTIRE AREA...WITH SOME WEAKENING OVER THE EAST PART OF THE AREA. HOWEVER OVER THE LAST HOUR OR SO THE LINE OF STORMS HAS ALMOST COMPLETELY DISSIPATED. LOOKING AT RUC THETA-E AT 850MB...THERE IS DRIER AIR OVER THE WESTERN HALF OF THE AREA. AM THINKING THIS IS WHY THE STORMS DIED OVER THE WEST INSTEAD OF THE EAST WHICH HAS HIGHER THETA-E AND BETTER CAPE. LOOKING SOUTHWARD NUMEROUS SHOWERS AND SOME T-STORMS CONTINUE TO MOVE UP FROM THE SOUTH IN THE HIGHER THETA-E AIR. LIFT DOES DECLINE OVER THE EAST OVERNIGHT SO HAVE RAINFALL CHANCES TRENDING ACCORDINGLY. DOES LOOK LIKE THE EAST HALF WILL HAVE A MUCH BETTER CHANCE FOR RAINFALL DUE TO THE HIGHER THETA-E AIR PRESENT. MEANWHILE PATCHY FOG IS EXPECTED OVER THE NORTHERN HALF OR SO OF THE AREA OVERNIGHT INTO TUESDAY MORNING. LOOKS LIKE THE FOG WILL BE NORTH OF THE SLOWLY ADVANCING SURFACE BOUNDARY. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 220 PM MDT MON MAY 4 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW DEEPENING TROUGH OVER SOUTHERN CALIFORNIA WITH SW FLOW FROM THE GULF OF ALASKA AND ACROSS THE CENTRAL/HIGH PLAINS. MOIST PLUME EXTENDS FROM THE GREAT BASIN ACROSS THE OHIO RIVER VALLEY WITH ADDITIONAL MOISTURE FEEDING IN THE PLAINS FROM THE GULF OF MEXICO. AT THE SURFACE A STATIONARY FRONT EXTENDS FROM NORTHEAST KANSAS TO SOUTHEAST COLORADO AND LIES JUST SOUTHEAST OF OUR CWA...WITH BAROCLINIC ZONE EXTENDING NORTH INTO THE SE PART OF OUR CWA. THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG THIS FRONTAL ZONE TOWARDS THE SOUTHEAST PART OF OUR CWA. THIS AFTERNOON-EVENING...ALONG THIS FRONTAL ZONE ANALYSIS INDICATES ML CAPE VALUES RANGING FROM 1500 J/KG IN THE WARM SECTOR TO 500 J/KG IN OUR SE CWA. BULK SHEER IS APPROXIMATELY 30-35KT...SO DEPENDING ON POSITION OF FRONT (CURRENTLY ADVERTISED TO SLIDE NORTH INTO OUR SOUTHEAST)...THERE IS THE POTENTIAL FOR A FEW STRONGER THUNDERSTORMS...POSSIBLY SEVERE WITH LARGE HAIL/DAMAGING WINDS MAIN THREAT. IF FRONT WERE TO LIFT NORTH AS WARM FRONT WE COULD SEE BETTER SB/ML CAPE AND THE POSSIBILITY FOR A FEW MORE ORGANIZED CELLS IN THE SOUTHEAST. ANALYSIS ALSO INDICATES PWAT VALUES ALREADY IN EXCESS OF 1" OVER OUR EAST. STORM MOTIONS WILL BE ROUGHLY TANGENTIAL/PARALLEL THIS AFTERNOON BECOMING PERPENDICULAR TO FRONTAL ZONE THIS EVENING. AS THIS TRANSITION OCCURS THERE IS THE FOR BACKBUILDING OR TRAINING AS VERY MOIST/UNSTABLE AIR IN THE WARM SECTOR FEEDS NORTH. THERE COULD BE A THREAT FOR FLASH FLOODING IF THIS SCENARIO PLAYS OUT. EITHER WAY WITH VERY MOIST AIR MASS AND INCREASING ELEVATED INSTABILITY...THUNDERSTORMS COULD BE VERY EFFICIENT RAINFALL PRODUCERS. TONIGHT-TUESDAY...UPSTREAM AREAS OF MID LEVEL VORTICITY WILL ROTATE INTO THE CWA WITH INCREASING LIFT LATE THIS EVENING INTO THE OVERNIGHT. AS TROUGH CONTINUES TO DEEPEN OVER THE SW US AND MOVE EAST WE WILL CONTINUE TO SEE VERY GOOD FORCING/MOISTURE ROTATES THROUGH THE REGION. LARGE SCALE Q VECTOR FIELDS INDICATED FORCING INCREASING THROUGH THE NIGHT AND OMEGA/MOISTURE CONVERGENCE FIELDS SHOW SUPPORT FOR INCREASING COVERAGE/COMPLEX OF SHOWERS THUNDERSTORMS. ELEVATED INSTABILITY TRANSITIONS NORTHWARD AND WEAKENS...HOWEVER THERE IS ENOUGH TO KEEP THUNDER MENTION IN PLACE THROUGH TUESDAY AFTERNOON. WHILE GUIDANCE IS IN AGREEMENT ON GENERAL LARGE SCALE PATTERN THE MAIN DIFFERENCES ARE ON TIMING OF POTENTIAL PERIODS OF HEAVIER PRECIP...WITH BEST PRECIP SIGNAL AND MOISTURE PROFILES OVERLAPPING TUESDAY MORNING THROUGH TUESDAY AFTERNOON ACROSS THE WESTERN 2/3 OF THE CWA (THOUGH ECMWF MIGHT BE A LITTLE EAST). THERE WILL BE MODERATE/ELEVATED INSTABILITY IN PLACE THROUGH THE DAY TUESDAY...SO STRONG TO SEVERE THUNDERSTORMS WILL STILL BE POSSIBLE AGAIN...THOUGH SEVERE POTENTIAL MIGHT NOT BE AS GOOD AS TODAY WITH WIDESPREAD SHOWERS AND STRATUS LIMITING SURFACE BASED PARCELS AND ANY ACTIVITY LIKELY EMBEDDED WITH OTHER SHOWER CLUSTERS. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 227 AM MDT TUE MAY 5 2015 A HIGH AMPLITUDE TROUGH WITH A CLOSED LOW WILL AFFECT THE TRI STATE AREA TO START THE LONG TERM FORECAST PERIOD FRIDAY...WHICH WILL BRING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE FORECAST AREA FOR THE DURATION OF THE FORECAST PERIOD. GFS/ECMWF/CANADIAN FORECASTS ALL INDICATE THE SLOW MOVING TROUGH WILL AFFECT THE REGION FOR THE DURATION OF THE COMING WEEKEND. THE TROUGH TAKES A NEGATIVE TILT SATURDAY IN THE GFS/ECMWF FORECASTS...WHICH WILL STEEPEN LAPSE RATES ALOFT AND INCREASE CAPE VALUES. A STRONGER JET MAY ALSO BE IN THE AREA TO HELP DESTABILIZE THE ENVIRONMENT...BUT MODEL GUIDANCE DIFFERS AS TO THE ACTUAL STRENGTH. GFS FORECAST HAS AN UPPER LEVEL JET APPROACHING 80KTS OVER THE FORECAST AREA...WHICH IS PLENTY STRONG TO GIVE 0-6 KM BULK SHEAR VALUES APPROACHING 50 KTS. LOWER LEVEL HODOGRAPHS ALSO HAVE GOOD CURVATURE WITH 0-3 KM HELICITY APPROACHING CRITICAL VALUES FOR TORNADOES. HOWEVER...ECMWF/CANADIAN MODELS ARE NOT AS ENTHUSIASTIC AND HAVE BETTER JET LOCATED TO THE EAST OF OUR AREA. THEREFORE...SEVERE THUNDERSTORM THREAT LOOKS TO BE POSSIBLE BUT NOT DEFINITE AT THIS POINT. HEAVY RAIN IS POSSIBLE SATURDAY NIGHT FOR MANY LOCATIONS DUE TO VERY SATURATED MODEL SOUNDINGS AND CAPE IN THE PROFILE TO CONTINUE TO DRIVE CONVECTION INTO THE EVENING. ALONG AN ADVANCING WARM FRONT...AN MCS IS LIKELY TO DEVELOP AND BE PERSISTENT WITH THE ENHANCEMENT OF THE LOWER NOCTURNAL JET. SHOWERS AND STORMS WILL TAPER OFF TOWARDS SUNDAY MORNING. SCATTERED THUNDERSTORMS MAY CONTINUE INTO THE AFTERNOON HOURS WITH THE UPPER LEVEL TROUGH LINGERING IN THE AREA...BUT THE BASE OF THE TROUGH WILL PASS OVER THE HIGH PLAINS MONDAY AND WILL EFFECTIVELY END THE HIGHER PRECIPITATION THREAT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1142 PM MDT MON MAY 4 2015 MVFR TO IFR CONDITIONS FORECAST FOR THE 6Z TAFS. EXPECT CONDITIONS AT KMCK TO REMAIN UNCHANGED UNTIL CLOSE TO MID MORNING. MEANWHILE AT KGLD CEILINGS HAVE FLUCTUATED FROM IFR TO VFR OVER THE PAST HOUR OR SO. EXPECT IFR CEILING IN THE NEXT HOUR. FOR BOTH SITES CEILINGS SHOULD INCREASE TO MVFR DURING THE LATE MORNING...THEN FALL TO IFR AGAIN IN THE EARLY EVENING. THE SHOWERS SHOULD REMAIN SOUTH OF KMCK FOR THE REST OF THE NIGHT AND THROUGH MOST OF THE DAY. DURING THE LATE AFTERNOON THERE MAY BE A SHORT WINDOW FOR STORMS TO MOVE NEAR THE SITE...BUT WILL WAIT FOR LATER TAFS TO ADDRESS THIS. KGLD SHOULD REMAIN RAIN FREE TONIGHT. DURING THE LATE MORNING AND THROUGH THE AFTERNOON RAIN CHANCES WILL INCREASE...WITH THE BEST CHANCES DURING THE MID TO LATE AFTERNOON. BY EARLY EVENING THE CHANCES FOR RAIN WILL BEGIN TO DECLINE. EXPECT VISIBILITY REDUCTION FOR BOTH SITES DURING THE OVERNIGHT HOURS. VISIBILITY SHOULD IMPROVE DURING THE MID TO LATE MORNING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...MK AVIATION...JTL
AREA FORECAST DISCUSSION
NWS WICHITA KS
313 AM CDT TUE MAY 5 2015 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 307 AM CDT TUE MAY 5 2015 LINGERING SHOWERS AND THUNDERSTORMS CONTINUE ALONG A QUASI STATIONARY BOUNDARY SITUATED JUST NORTH OF INTERSTATE 70 AT THIS TIME. LATEST SHORT TERM HI-RES MODELS SUGGEST THIS BOUNDARY WILL SLOWLY LIFT BACK TO THE NORTH THIS MORNING TOWARDS NEB...TAKING MOST OF THE SHOWER ACTIVITY NORTH WITH IT. THIS WILL LEAD TO DRY CONDITIONS FOR THE DAYTIME HOURS ACROSS THE FORECAST AREA...AS A WARM ELEVATED MIXED LAYER CAPS OFF ANY PRECIP CHANCE WITH LESS INSTABILITY THIS AFTERNOON. THE MAIN DRYLINE AND CONVERGENCE FOR STORM CHANCES LOOKS TO SHIFT INTO WESTERN KS FOR THIS AFTERNOON INTO THIS EVENING. THINK SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THIS DRYLINE AND MAKE SLOW PROGRESS TO THE EAST...AS AN INITIAL SHORTWAVE ROTATES NORTH ACROSS WESTERN KS LATE THIS AFTERNOON. BUT EXPECT ANOTHER MORE POTENT SHORTWAVE TO ROTATE NORTH OUT OF SRN NM DURING THE EVENING WITH THIS SHORTWAVE LIFTING NORTHEAST ACROSS THE FORECAST AREA FOR THE LATE EVENING AND OVERNIGHT HOURS. LIFT ASSOCIATED WITH THIS SHORTWAVE WILL LEAD TO SHOWERS INITIALLY DEVELOPING IN OK...WITH THE STORMS MOVING NORTH INTO THE AREA DURING THE LATE EVENING HOURS. AS THIS IMPULSE MOVES ACROSS THE AREA...WIDESPREAD SHOWERS AND SOME EMBEDDED THUNDERSTORMS WILL BLOSSOM ACROSS MOST OF THE FORECAST AREA FOR THE OVERNIGHT HOURS AS THE UPPER LEVEL DIFFLUENCE INCREASES. PREVIOUS SHIFTS ADJUSTED THE POP TIMING WITH CATEGORICAL POPS MAINLY AFTER 06Z...WITH LIKELY POPS FOR THE EVENING HOURS. THIS LOOKS OKAY. SOME UNCERTAINTY ON HOW EARLY WED WILL PLAY OUT...AS REMNANT SHOWERS AND EMBEDDED THUNDER WILL STILL BE ACROSS CENTRAL KS FOR THE MORNING HOURS. LOTS OF REMNANT CLOUD COVER WILL ALSO BE AROUND...AS INSTABILITY INCREASES AND THE DRYLINE PUSHES EAST CLOSER TO THE FORECAST AREA FOR WED AFTERNOON. IF AIRMASS CAN RECOVER...LATEST NAM/WRF AND GFS SHOW A VERY UNSTABLE AIRMASS WILL BE IN PLACE ACROSS SOUTH CENTRAL KS...WITH DEEP LAYER BULK SHEAR INCREASING TO AROUND 30-40 KTS. WEAKLY CAPPED ENVIRONMENT WILL BE IN PLACE..SO EXPECT DISCRETE STORMS TO DEVELOP ALONG THIS DRYLINE FOR WED AFTERNOON....WITH STORMS EXPECTED TO BECOME SUPERCELLS GIVEN THE DIRECTIONAL SHEAR. THIS CERTAINLY LOOKS LIKE A SEVERE WEATHER THREAT WITH LARGE HAIL AND DAMAGING WINDS THE MAIN CONCERN. DRYLINE IS EXPECTED TO RETREAT BACK TO THE WEST DURING THE NIGHTTIME HOURS ON WED...SO NOT ENTIRELY SURE HOW LONG THE CONVECTION WILL CONTINUE INTO WED NIGHT...AS SOME WARMER AIR ALOFT WILL EFFECTIVELY SHUT DOWN THE CONVECTION. THE DRYLINE WILL AGAIN COME INTO PLAY ON THU...AS THE BOUNDARY BECOMES MORE OF A COLD FRONT AND AGAIN PUSHES INTO PORTIONS OF CENTRAL KS FOR THU AFTERNOON AS A NORTHERN STREAM SYSTEM HELPS PUSH IT FURTHER EAST. INSTABILITY AND SHEAR SUGGESTS ANOTHER ROUND OF SEVERE WEATHER MAY OCCUR ALONG THIS BOUNDARY FOR PORTIONS OF THE FORECAST AREA FOR THU AFTERNOON/EVENING...AS SUPERCELLS WILL AGAIN BE POSSIBLE. WILL HAVE TO KEEP AN EYE ON THIS SEVERE WEATHER THREAT...AS AN AREA OF LOW PRESSURE IN THE OK PANHANDLE MAY SETUP A TRIPLE POINT ACROSS SOUTH CENTRAL KS...WITH SURFACE WINDS BACKING ACROSS SRN KS AND BETTER LOW LEVEL TURNING FOR A POSSIBLE INCREASED TORNADO THREAT. STAY TUNED. KETCHAM .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 307 AM CDT TUE MAY 5 2015 THE ACTIVE PATTERN LOOKS TO CONTINUE FOR FRI AND SAT...AS THE MAIN SURFACE BOUNDARY BECOMES STATIONARY ACROSS SOUTHERN KS ON FRI AFTERNOON. THE MID LEVEL BAROCLINIC ZONE WILL ALSO REMAIN CO- LOCATED WITH THE SURFACE BOUNDARY AS WELL....WITH SHOWER AND THUNDERSTORMS EXPECTED TO REDEVELOP ACROSS SOUTHERN KS AS THE LOW LEVEL JET INCREASES OVER THE TOP OF THE BOUNDARY. THIS HAS ALL THE SIGNS OF A SEVERE WEATHER PRODUCING COMPLEX OF STORMS (MCS) DEVELOPING LATE FRI NIGHT ACROSS SRN KS...CONSIDERING THE AMOUNT OF INSTABILITY THAT WILL BE AROUND AND BULK SHEAR OF 40 KTS. HOW SAT WILL PLAY OUT WILL DEPEND ON WHERE THE MCS LATE FRI NIGHT GOES AND ANY OUTFLOW BOUNDARY IT PUSHES OUT. MEDIUM RANGE MODELS SUGGEST THAT A VIGOROUS SHORTWAVE IS EXPECTED TO LIFT NORTHEAST OUT OF THE SOUTHERN PLAINS ON SAT EVENING AND WILL PUSH ANY KIND OF BOUNDARY/WARM FRONT BACK NORTH ACROSS THE AREA FOR SAT NIGHT...WHICH WILL LEAD TO ANOTHER CHANCE OF SEVERE STORMS FOR SAT NIGHT AS WELL. WILL CERTAINLY HAVE TO KEEP AN EYE ON WATER ISSUES GOING INTO THE WEEKEND...AS MOST OF THE CONVECTION WILL BE VERY EFFECTIVE RAINFALL PRODUCERS FOR HEAVY RAINFALL AND POSSIBLE FLOODING CONCERNS. KETCHAM && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1150 PM CDT MON MAY 4 2015 STORMS HAVE BEEN A BIT SLOWER TO EXIT CENTRAL KS THAN ANTICIPATED... BUT SHORT TERM MODELS ARE STILL ADAMANT THAT PRECIPITATION WILL PUSH NORTH EARLY IN THE FORECAST. LATEST RAP IS A BIT DIFFERENT KEEPING OUTFLOW/SURFACE BOUNDARY QUASISTATIONARY BUT STILL MOVING PRECIPITATION TO THE NORTH. THIS SEEMS PLAUSIBLE BASED ON RADAR TRENDS. FOCUS THEN TURNS TO TIMING OF CONVECTION TOMORROW. OUTFLOW BOUNDARY MIGHT FOCUS INITIAL UPDRAFTS...BUT INABILITY TO ACCURATELY FORECAST ITS LOCATION PRECLUDES AN EARLY MENTION IN TAFS. WILL STICK WITH HIGHER PROBABILITY OF JUST PRIOR TO 0000 UTC AT KRSL/KHUT AND AFTER 0000 UTC AT KSLN/KHUT. HAVE KEPT KCNU DRY FOR NOW...BUT ROGUE CELL COULD AFFECT KCNU DURING PK HEATING. -HOWERTON && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 77 62 77 65 / 10 90 60 40 HUTCHINSON 76 61 76 63 / 10 90 50 50 NEWTON 74 60 75 62 / 10 90 60 40 ELDORADO 79 62 75 64 / 10 90 70 40 WINFIELD-KWLD 77 63 76 65 / 10 90 60 40 RUSSELL 75 59 78 60 / 40 80 50 50 GREAT BEND 73 59 78 62 / 50 80 40 40 SALINA 78 61 76 65 / 10 90 50 50 MCPHERSON 75 61 75 63 / 10 90 50 50 COFFEYVILLE 78 63 75 65 / 10 80 80 40 CHANUTE 79 62 75 64 / 10 70 80 30 IOLA 78 62 75 64 / 10 70 80 30 PARSONS-KPPF 79 63 75 65 / 10 70 80 30 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1149 PM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 1023 PM MDT MON MAY 4 2015 UPDATED FORECAST TO REFLECT THE DIMINISHED CHANCES FOR RAINFALL FOR THE WESTERN HALF OR SO OF THE AREA THROUGH THE REST OF THE NIGHT. WAS VERY CONFIDENT EARLIER THAT THE LINE OF STORMS WOULD MOVE ACROSS THE ENTIRE AREA...WITH SOME WEAKENING OVER THE EAST PART OF THE AREA. HOWEVER OVER THE LAST HOUR OR SO THE LINE OF STORMS HAS ALMOST COMPLETELY DISSIPATED. LOOKING AT RUC THETA-E AT 850MB...THERE IS DRIER AIR OVER THE WESTERN HALF OF THE AREA. AM THINKING THIS IS WHY THE STORMS DIED OVER THE WEST INSTEAD OF THE EAST WHICH HAS HIGHER THETA-E AND BETTER CAPE. LOOKING SOUTHWARD NUMEROUS SHOWERS AND SOME T-STORMS CONTINUE TO MOVE UP FROM THE SOUTH IN THE HIGHER THETA-E AIR. LIFT DOES DECLINE OVER THE EAST OVERNIGHT SO HAVE RAINFALL CHANCES TRENDING ACCORDINGLY. DOES LOOK LIKE THE EAST HALF WILL HAVE A MUCH BETTER CHANCE FOR RAINFALL DUE TO THE HIGHER THETA-E AIR PRESENT. MEANWHILE PATCHY FOG IS EXPECTED OVER THE NORTHERN HALF OR SO OF THE AREA OVERNIGHT INTO TUESDAY MORNING. LOOKS LIKE THE FOG WILL BE NORTH OF THE SLOWLY ADVANCING SURFACE BOUNDARY. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 220 PM MDT MON MAY 4 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW DEEPENING TROUGH OVER SOUTHERN CALIFORNIA WITH SW FLOW FROM THE GULF OF ALASKA AND ACROSS THE CENTRAL/HIGH PLAINS. MOIST PLUME EXTENDS FROM THE GREAT BASIN ACROSS THE OHIO RIVER VALLEY WITH ADDITIONAL MOISTURE FEEDING IN THE PLAINS FROM THE GULF OF MEXICO. AT THE SURFACE A STATIONARY FRONT EXTENDS FROM NORTHEAST KANSAS TO SOUTHEAST COLORADO AND LIES JUST SOUTHEAST OF OUR CWA...WITH BAROCLINIC ZONE EXTENDING NORTH INTO THE SE PART OF OUR CWA. THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG THIS FRONTAL ZONE TOWARDS THE SOUTHEAST PART OF OUR CWA. THIS AFTERNOON-EVENING...ALONG THIS FRONTAL ZONE ANALYSIS INDICATES ML CAPE VALUES RANGING FROM 1500 J/KG IN THE WARM SECTOR TO 500 J/KG IN OUR SE CWA. BULK SHEER IS APPROXIMATELY 30-35KT...SO DEPENDING ON POSITION OF FRONT (CURRENTLY ADVERTISED TO SLIDE NORTH INTO OUR SOUTHEAST)...THERE IS THE POTENTIAL FOR A FEW STRONGER THUNDERSTORMS...POSSIBLY SEVERE WITH LARGE HAIL/DAMAGING WINDS MAIN THREAT. IF FRONT WERE TO LIFT NORTH AS WARM FRONT WE COULD SEE BETTER SB/ML CAPE AND THE POSSIBILITY FOR A FEW MORE ORGANIZED CELLS IN THE SOUTHEAST. ANALYSIS ALSO INDICATES PWAT VALUES ALREADY IN EXCESS OF 1" OVER OUR EAST. STORM MOTIONS WILL BE ROUGHLY TANGENTIAL/PARALLEL THIS AFTERNOON BECOMING PERPENDICULAR TO FRONTAL ZONE THIS EVENING. AS THIS TRANSITION OCCURS THERE IS THE FOR BACKBUILDING OR TRAINING AS VERY MOIST/UNSTABLE AIR IN THE WARM SECTOR FEEDS NORTH. THERE COULD BE A THREAT FOR FLASH FLOODING IF THIS SCENARIO PLAYS OUT. EITHER WAY WITH VERY MOIST AIR MASS AND INCREASING ELEVATED INSTABILITY...THUNDERSTORMS COULD BE VERY EFFICIENT RAINFALL PRODUCERS. TONIGHT-TUESDAY...UPSTREAM AREAS OF MID LEVEL VORTICITY WILL ROTATE INTO THE CWA WITH INCREASING LIFT LATE THIS EVENING INTO THE OVERNIGHT. AS TROUGH CONTINUES TO DEEPEN OVER THE SW US AND MOVE EAST WE WILL CONTINUE TO SEE VERY GOOD FORCING/MOISTURE ROTATES THROUGH THE REGION. LARGE SCALE Q VECTOR FIELDS INDICATED FORCING INCREASING THROUGH THE NIGHT AND OMEGA/MOISTURE CONVERGENCE FIELDS SHOW SUPPORT FOR INCREASING COVERAGE/COMPLEX OF SHOWERS THUNDERSTORMS. ELEVATED INSTABILITY TRANSITIONS NORTHWARD AND WEAKENS...HOWEVER THERE IS ENOUGH TO KEEP THUNDER MENTION IN PLACE THROUGH TUESDAY AFTERNOON. WHILE GUIDANCE IS IN AGREEMENT ON GENERAL LARGE SCALE PATTERN THE MAIN DIFFERENCES ARE ON TIMING OF POTENTIAL PERIODS OF HEAVIER PRECIP...WITH BEST PRECIP SIGNAL AND MOISTURE PROFILES OVERLAPPING TUESDAY MORNING THROUGH TUESDAY AFTERNOON ACROSS THE WESTERN 2/3 OF THE CWA (THOUGH ECMWF MIGHT BE A LITTLE EAST). THERE WILL BE MODERATE/ELEVATED INSTABILITY IN PLACE THROUGH THE DAY TUESDAY...SO STRONG TO SEVERE THUNDERSTORMS WILL STILL BE POSSIBLE AGAIN...THOUGH SEVERE POTENTIAL MIGHT NOT BE AS GOOD AS TODAY WITH WIDESPREAD SHOWERS AND STRATUS LIMITING SURFACE BASED PARCELS AND ANY ACTIVITY LIKELY EMBEDDED WITH OTHER SHOWER CLUSTERS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 124 PM MDT MON MAY 4 2015 MAIN TROUGH AXIS WILL LIFT NORTHEAST ACROSS THE AREA TUESDAY NIGHT WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUING. AFTER MIDNIGHT...GENERAL TREND WILL BE FOR A WEST TO EAST END OF THE PRECIPITATION AS DRY SLOT WORKS IN BEHIND THE TROUGH. AFTER A LULL WEDNESDAY MORNING...WRAPAROUND PRECIPITATION WILL MOVE IN FROM COLORADO WEDNESDAY AFTERNOON AND BECOME WIDESPREAD WEDNESDAY NIGHT. A COLD FRONT WILL ALSO MOVE THROUGH WEDNESDAY NIGHT WHICH WILL PROVIDE A FOCUS FOR THUNDERSTORMS IN THE EVENING...BUT THE POST FRONTAL ENVIRONMENT HAS ONLY LIMITED ELEVATED INSTABILITY AND EXPECT ONLY ISOLATED THUNDERSTORMS THROUGH THURSDAY MORNING. HOWEVER BY THURSDAY AFTERNOON SBCAPE INCREASES ONCE AGAIN AND A COMBINATION OF MOIST LOW LEVEL UPSLOPE AND ANOTHER SHORTWAVE TROUGH IN THE SOUTHWESTERLY FLOW ALOFT WILL RESULT IN THUNDERSTORM DEVELOPMENT IN EASTERN COLORADO WHICH WILL MOVE INTO NORTHWEST KANSAS AND SOUTHWEST NEBRASKA THURSDAY EVENING. SEVERE THREAT WILL DEPEND ON HOW MUCH INSTABILITY CAN DEVELOP AFTER A CLOUDY MORNING...BUT DEEP LAYER SHEAR WOULD BE SUPPORTIVE OF ORGANIZED UPDRAFTS THROUGH EARLY EVENING BEFORE BOUNDARY LAYER DECOUPLES WITH NOCTURNAL COOLING. OVERALL PATTERN CHANGES LITTLE ON FRIDAY ALTHOUGH MODELS SHOWING ONLY MINIMAL SBCAPE AVAILABLE SO SEVERE THREAT MAY NOT BE AS GREAT. ANOTHER STRONG UPPER LOW WILL KICK OUT OF THE DESERT SOUTHWEST ON SATURDAY WITH A NEGATIVE TILT AND PROVIDE THE SYNOPTIC SCALE FORCING FOR THUNDERSTORMS. THE PATTERN SUGGESTS A SEVERE THREAT WITH MODELS SHOWING DEEP LAYER SHEAR OF OVER 50KTS AND SUFFICIENT INSTABILITY FOR SUPERCELLS. IF CURRENT TIMING TRENDS CONTINUE WOULD EXPECT TO SEE A DRY SLOT SATURDAY NIGHT FOLLOWED BY WRAPAROUND PRECIPITATION CHANCES ON SUNDAY. THE PATTERN FINALLY CHANGES BY EARLY NEXT WEEK WITH SUBTLE SHORTWAVE RIDGING IN A ZONAL FLOW WHICH WOULD TRANSLATE TO DRY CONDITIONS AND SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1142 PM MDT MON MAY 4 2015 MVFR TO IFR CONDITIONS FORECAST FOR THE 6Z TAFS. EXPECT CONDITIONS AT KMCK TO REMAIN UNCHANGED UNTIL CLOSE TO MID MORNING. MEANWHILE AT KGLD CEILINGS HAVE FLUCTUATED FROM IFR TO VFR OVER THE PAST HOUR OR SO. EXPECT IFR CEILING IN THE NEXT HOUR. FOR BOTH SITES CEILINGS SHOULD INCREASE TO MVFR DURING THE LATE MORNING...THEN FALL TO IFR AGAIN IN THE EARLY EVENING. THE SHOWERS SHOULD REMAIN SOUTH OF KMCK FOR THE REST OF THE NIGHT AND THROUGH MOST OF THE DAY. DURING THE LATE AFTERNOON THERE MAY BE A SHORT WINDOW FOR STORMS TO MOVE NEAR THE SITE...BUT WILL WAIT FOR LATER TAFS TO ADDRESS THIS. KGLD SHOULD REMAIN RAIN FREE TONIGHT. DURING THE LATE MORNING AND THROUGH THE AFTERNOON RAIN CHANCES WILL INCREASE...WITH THE BEST CHANCES DURING THE MID TO LATE AFTERNOON. BY EARLY EVENING THE CHANCES FOR RAIN WILL BEGIN TO DECLINE. EXPECT VISIBILITY REDUCTION FOR BOTH SITES DURING THE OVERNIGHT HOURS. VISIBILITY SHOULD IMPROVE DURING THE MID TO LATE MORNING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...024 AVIATION...JTL
AREA FORECAST DISCUSSION
NWS WICHITA KS
1153 PM CDT MON MAY 4 2015 ...UPDATED FOR 06Z AVIATION DISCUSSION... .UPDATE... ISSUED AT 839 PM CDT MON MAY 4 2015 CURRENT THINKING BASED ON QUICK LOOK AT 00Z DATA AND RECENT HI RES MODELS SUG STORMS MAY HANG ON A BIT LONGER...BUT SHOULD DIMINISH SHORTLY AFTER MIDNIGHT. APPEARS THAT 30-35KT 850MB JET IS IMPINGING ON THE 850MB BOUNDARY THAT EXTENDS FROM NORTHEAST TO SOUTHWEST ACROSS THE STATE. SEVERE THUNDERSTORM WATCH WILL EXPIRE ON SCHEDULE AS STORMS HAVE CONTINUED TO SHOW A SLOW WEAKENING TREND. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 312 PM CDT MON MAY 4 2015 DEEP MOIST CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON AND EVENING ALONG A STALLED FRONTAL BOUNDARY ACROSS CENTRAL KS WHERE THE HIGHEST POPS WILL BE MAINTAINED. OTHER MORE ISOLATED DIURNALLY DRIVEN ACTIVITY WILL BE POSSIBLE THROUGH EARLY EVENING ACROSS SOUTHERN KANSAS. SOME OF THE HIGHER RESOLUTION MODEL GUIDANCE IS SUGGESTING THAT OUTFLOW WILL FORCE THE BOUNDARY FURTHER SOUTH AND TRENDED POPS UP SLIGHTLY ACROSS PORTIONS OF SOUTH CENTRAL AND SOUTHEAST KS TO ACCOUNT FOR THIS SCENARIO. BY 07-09Z THE WARM FRONT IS EXPECTED TO LIFT NORTH BRINGING AN END TO ANY LINGERING PRECIPITATION. MUCH OF TUESDAY MAY BE DRY BUT MAINTAINED MID POPS ACROSS PORTIONS OF CENTRAL AND SOUTH CENTRAL KANSAS AS ANY ACTIVITY DEVELOPING ACROSS SW KS MAY DRIFT NORTHEAST ACROSS THE AREA LATER IN THE DAY AND THE AIRMASS IS PROGGED TO REMAIN WEAKLY CAPPED. BETTER CHANCES FOR MORE WIDESPREAD PRECIPITATION WILL ARRIVE LATE TUE NIGHT INTO EARLY WED AS A VIGOROUS SHORTWAVE TROUGH EMERGES OVER THE CENTRAL HIGH PLAINS. THIS WAS HANDLED WELL IN THE PREVIOUS FORECAST AND THE PRIMARY CHANGE WAS TO SLOW POPS WITH THE HIGHEST PROBABILITIES ARRIVING AFTER 06Z ACROSS THE FORECAST AREA. WED-THU...THE DEEP LAYER SHEAR IS PROGGED TO INCREASE ON WED AS THE FOCUS FOR DEEP MOIST CONVECTION IS EXPECTED TO DEVELOP ALONG HWY 281 ALONG A DRYLINE. MAINTAINED MID POPS WED NIGHT INTO THU AS THE AIRMASS IS PROGGED TO REMAIN UNSTABLE WITH A CONTINUATION OF SOUTHWEST MID/UPPER FLOW. TIMING ANY SHORTWAVE TROUGHS LIFTING OUT OF THE SOUTHWEST BECOMES CHALLENGING AT THIS POINT. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 312 PM CDT MON MAY 4 2015 A MID/UPPER TROUGH OVER THE SOUTHWEST AT THE BEGINNING OF THE PERIOD IS PROGGED TO MOVE EAST/NORTHEAST INTO THE SOUTHERN AND CENTRAL ROCKIES OVER THE WEEKEND. RICH MOISTURE IS PROGGED TO REMAIN ENTRENCHED ACROSS THE SOUTHERN AND CENTRAL PLAINS STATES WHERE MULTIPLE ROUNDS OF DEEP MOIST CONVECTION ARE EXPECTED LATE IN THE WEEK AND INTO THE WEEKEND. MAINTAINED MID POPS THROUGH MUCH OF THE PERIOD WITH SEASONABLY MILD TEMPERATURES ANTICIPATED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1150 PM CDT MON MAY 4 2015 STORMS HAVE BEEN A BIT SLOWER TO EXIT CENTRAL KS THAN ANTICIPATED... BUT SHORT TERM MODELS ARE STILL ADAMANT THAT PRECIPITATION WILL PUSH NORTH EARLY IN THE FORECAST. LATEST RAP IS A BIT DIFFERENT KEEPING OUTFLOW/SURFACE BOUNDARY QUASISTATIONARY BUT STILL MOVING PRECIPITATION TO THE NORTH. THIS SEEMS PLAUSIBLE BASED ON RADAR TRENDS. FOCUS THEN TURNS TO TIMING OF CONVECTION TOMORROW. OUTFLOW BOUNDARY MIGHT FOCUS INITIAL UPDRAFTS...BUT INABILITY TO ACCURATELY FORECAST ITS LOCATION PRECLUDES AN EARLY MENTION IN TAFS. WILL STICK WITH HIGHER PROBABILITY OF JUST PRIOR TO 0000 UTC AT KRSL/KHUT AND AFTER 0000 UTC AT KSLN/KHUT. HAVE KEPT KCNU DRY FOR NOW...BUT ROGUE CELL COULD AFFECT KCNU DURING PK HEATING. -HOWERTON && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 62 77 63 77 / 20 20 90 60 HUTCHINSON 62 76 61 77 / 40 20 90 50 NEWTON 61 74 59 73 / 20 10 90 60 ELDORADO 61 79 63 76 / 10 10 90 70 WINFIELD-KWLD 61 77 62 76 / 10 20 90 60 RUSSELL 59 75 59 78 / 70 50 80 50 GREAT BEND 59 73 59 78 / 90 60 80 40 SALINA 61 78 61 77 / 90 20 90 50 MCPHERSON 61 75 60 74 / 50 20 90 50 COFFEYVILLE 59 78 63 74 / 10 20 80 80 CHANUTE 60 79 63 75 / 10 10 70 80 IOLA 60 78 63 73 / 10 10 70 80 PARSONS-KPPF 59 79 63 75 / 10 20 70 80 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1030 PM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 1023 PM MDT MON MAY 4 2015 UPDATED FORECAST TO REFLECT THE DIMINISHED CHANCES FOR RAINFALL FOR THE WESTERN HALF OR SO OF THE AREA THROUGH THE REST OF THE NIGHT. WAS VERY CONFIDENT EARLIER THAT THE LINE OF STORMS WOULD MOVE ACROSS THE ENTIRE AREA...WITH SOME WEAKENING OVER THE EAST PART OF THE AREA. HOWEVER OVER THE LAST HOUR OR SO THE LINE OF STORMS HAS ALMOST COMPLETELY DISSIPATED. LOOKING AT RUC THETA-E AT 850MB...THERE IS DRIER AIR OVER THE WESTERN HALF OF THE AREA. AM THINKING THIS IS WHY THE STORMS DIED OVER THE WEST INSTEAD OF THE EAST WHICH HAS HIGHER THETA-E AND BETTER CAPE. LOOKING SOUTHWARD NUMEROUS SHOWERS AND SOME T-STORMS CONTINUE TO MOVE UP FROM THE SOUTH IN THE HIGHER THETA-E AIR. LIFT DOES DECLINE OVER THE EAST OVERNIGHT SO HAVE RAINFALL CHANCES TRENDING ACCORDINGLY. DOES LOOK LIKE THE EAST HALF WILL HAVE A MUCH BETTER CHANCE FOR RAINFALL DUE TO THE HIGHER THETA-E AIR PRESENT. MEANWHILE PATCHY FOG IS EXPECTED OVER THE NORTHERN HALF OR SO OF THE AREA OVERNIGHT INTO TUESDAY MORNING. LOOKS LIKE THE FOG WILL BE NORTH OF THE SLOWLY ADVANCING SURFACE BOUNDARY. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 220 PM MDT MON MAY 4 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW DEEPENING TROUGH OVER SOUTHERN CALIFORNIA WITH SW FLOW FROM THE GULF OF ALASKA AND ACROSS THE CENTRAL/HIGH PLAINS. MOIST PLUME EXTENDS FROM THE GREAT BASIN ACROSS THE OHIO RIVER VALLEY WITH ADDITIONAL MOISTURE FEEDING IN THE PLAINS FROM THE GULF OF MEXICO. AT THE SURFACE A STATIONARY FRONT EXTENDS FROM NORTHEAST KANSAS TO SOUTHEAST COLORADO AND LIES JUST SOUTHEAST OF OUR CWA...WITH BAROCLINIC ZONE EXTENDING NORTH INTO THE SE PART OF OUR CWA. THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG THIS FRONTAL ZONE TOWARDS THE SOUTHEAST PART OF OUR CWA. THIS AFTERNOON-EVENING...ALONG THIS FRONTAL ZONE ANALYSIS INDICATES ML CAPE VALUES RANGING FROM 1500 J/KG IN THE WARM SECTOR TO 500 J/KG IN OUR SE CWA. BULK SHEER IS APPROXIMATELY 30-35KT...SO DEPENDING ON POSITION OF FRONT (CURRENTLY ADVERTISED TO SLIDE NORTH INTO OUR SOUTHEAST)...THERE IS THE POTENTIAL FOR A FEW STRONGER THUNDERSTORMS...POSSIBLY SEVERE WITH LARGE HAIL/DAMAGING WINDS MAIN THREAT. IF FRONT WERE TO LIFT NORTH AS WARM FRONT WE COULD SEE BETTER SB/ML CAPE AND THE POSSIBILITY FOR A FEW MORE ORGANIZED CELLS IN THE SOUTHEAST. ANALYSIS ALSO INDICATES PWAT VALUES ALREADY IN EXCESS OF 1" OVER OUR EAST. STORM MOTIONS WILL BE ROUGHLY TANGENTIAL/PARALLEL THIS AFTERNOON BECOMING PERPENDICULAR TO FRONTAL ZONE THIS EVENING. AS THIS TRANSITION OCCURS THERE IS THE FOR BACKBUILDING OR TRAINING AS VERY MOIST/UNSTABLE AIR IN THE WARM SECTOR FEEDS NORTH. THERE COULD BE A THREAT FOR FLASH FLOODING IF THIS SCENARIO PLAYS OUT. EITHER WAY WITH VERY MOIST AIR MASS AND INCREASING ELEVATED INSTABILITY...THUNDERSTORMS COULD BE VERY EFFICIENT RAINFALL PRODUCERS. TONIGHT-TUESDAY...UPSTREAM AREAS OF MID LEVEL VORTICITY WILL ROTATE INTO THE CWA WITH INCREASING LIFT LATE THIS EVENING INTO THE OVERNIGHT. AS TROUGH CONTINUES TO DEEPEN OVER THE SW US AND MOVE EAST WE WILL CONTINUE TO SEE VERY GOOD FORCING/MOISTURE ROTATES THROUGH THE REGION. LARGE SCALE Q VECTOR FIELDS INDICATED FORCING INCREASING THROUGH THE NIGHT AND OMEGA/MOISTURE CONVERGENCE FIELDS SHOW SUPPORT FOR INCREASING COVERAGE/COMPLEX OF SHOWERS THUNDERSTORMS. ELEVATED INSTABILITY TRANSITIONS NORTHWARD AND WEAKENS...HOWEVER THERE IS ENOUGH TO KEEP THUNDER MENTION IN PLACE THROUGH TUESDAY AFTERNOON. WHILE GUIDANCE IS IN AGREEMENT ON GENERAL LARGE SCALE PATTERN THE MAIN DIFFERENCES ARE ON TIMING OF POTENTIAL PERIODS OF HEAVIER PRECIP...WITH BEST PRECIP SIGNAL AND MOISTURE PROFILES OVERLAPPING TUESDAY MORNING THROUGH TUESDAY AFTERNOON ACROSS THE WESTERN 2/3 OF THE CWA (THOUGH ECMWF MIGHT BE A LITTLE EAST). THERE WILL BE MODERATE/ELEVATED INSTABILITY IN PLACE THROUGH THE DAY TUESDAY...SO STRONG TO SEVERE THUNDERSTORMS WILL STILL BE POSSIBLE AGAIN...THOUGH SEVERE POTENTIAL MIGHT NOT BE AS GOOD AS TODAY WITH WIDESPREAD SHOWERS AND STRATUS LIMITING SURFACE BASED PARCELS AND ANY ACTIVITY LIKELY EMBEDDED WITH OTHER SHOWER CLUSTERS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 124 PM MDT MON MAY 4 2015 MAIN TROUGH AXIS WILL LIFT NORTHEAST ACROSS THE AREA TUESDAY NIGHT WITH GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUING. AFTER MIDNIGHT...GENERAL TREND WILL BE FOR A WEST TO EAST END OF THE PRECIPITATION AS DRY SLOT WORKS IN BEHIND THE TROUGH. AFTER A LULL WEDNESDAY MORNING...WRAPAROUND PRECIPITATION WILL MOVE IN FROM COLORADO WEDNESDAY AFTERNOON AND BECOME WIDESPREAD WEDNESDAY NIGHT. A COLD FRONT WILL ALSO MOVE THROUGH WEDNESDAY NIGHT WHICH WILL PROVIDE A FOCUS FOR THUNDERSTORMS IN THE EVENING...BUT THE POST FRONTAL ENVIRONMENT HAS ONLY LIMITED ELEVATED INSTABILITY AND EXPECT ONLY ISOLATED THUNDERSTORMS THROUGH THURSDAY MORNING. HOWEVER BY THURSDAY AFTERNOON SBCAPE INCREASES ONCE AGAIN AND A COMBINATION OF MOIST LOW LEVEL UPSLOPE AND ANOTHER SHORTWAVE TROUGH IN THE SOUTHWESTERLY FLOW ALOFT WILL RESULT IN THUNDERSTORM DEVELOPMENT IN EASTERN COLORADO WHICH WILL MOVE INTO NORTHWEST KANSAS AND SOUTHWEST NEBRASKA THURSDAY EVENING. SEVERE THREAT WILL DEPEND ON HOW MUCH INSTABILITY CAN DEVELOP AFTER A CLOUDY MORNING...BUT DEEP LAYER SHEAR WOULD BE SUPPORTIVE OF ORGANIZED UPDRAFTS THROUGH EARLY EVENING BEFORE BOUNDARY LAYER DECOUPLES WITH NOCTURNAL COOLING. OVERALL PATTERN CHANGES LITTLE ON FRIDAY ALTHOUGH MODELS SHOWING ONLY MINIMAL SBCAPE AVAILABLE SO SEVERE THREAT MAY NOT BE AS GREAT. ANOTHER STRONG UPPER LOW WILL KICK OUT OF THE DESERT SOUTHWEST ON SATURDAY WITH A NEGATIVE TILT AND PROVIDE THE SYNOPTIC SCALE FORCING FOR THUNDERSTORMS. THE PATTERN SUGGESTS A SEVERE THREAT WITH MODELS SHOWING DEEP LAYER SHEAR OF OVER 50KTS AND SUFFICIENT INSTABILITY FOR SUPERCELLS. IF CURRENT TIMING TRENDS CONTINUE WOULD EXPECT TO SEE A DRY SLOT SATURDAY NIGHT FOLLOWED BY WRAPAROUND PRECIPITATION CHANCES ON SUNDAY. THE PATTERN FINALLY CHANGES BY EARLY NEXT WEEK WITH SUBTLE SHORTWAVE RIDGING IN A ZONAL FLOW WHICH WOULD TRANSLATE TO DRY CONDITIONS AND SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 555 PM MDT MON MAY 4 2015 VFR TO LIFR CONDITIONS FOR THE TAFS. CHALLENGING SET OF TAFS DUE TO TIMING OF THE DIFFERENT WAVES OF RAINFALL...THE CEILING HEIGHTS AND VISIBILITY. IN GENERAL LOOKS LIKE KGLD WILL HAVE A BETTER CHANCE FOR RECEIVING RAINFALL THAN KMCK...ESPECIALLY PROLONGED RAINFALL. BASED TIMING OF THE STORMS FOR BOTH SITES BY TRACKING THE SPEED OF THE CURRENT STORMS. IF STORM MOVEMENT CHANGES THAT WILL AFFECT THE TIMING IN THE TAFS. BASED ON OBSERVATIONS AND MODEL SOUNDINGS...LOOKS LIKE THE SECOND WAVE OF STORMS WILL CAUSE CEILINGS TO FALL. OVERNIGHT VISIBILITIES WILL DECLINE SOME BUT THEN IMPROVE BY MID MORNING. HAVE VC FOR KMCK DUE TO UNCERTAINTY THERE WILL STILL BE RAINFALL AT THE SITE DURING THE MORNING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...024 AVIATION...JTL
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1149 PM CDT MON MAY 4 2015 .AVIATION...A FEW SHOWERS WILL AFFECT KLCH AND KBPT THROUGH THE NEXT FEW HOURS AND THESE SHOWERS MAY LINGER THROUGH THE NIGHT. A FEW TSRA MAY BE IN VICINITY OF THESE TERMINAL TOMORROW, HOWEVER COVERAGE WILL DECREASE AS SUNSET APPROACHES. WITH ANY SHOWER MVFR CEILINGS AND VIS MAY OCCUR. LIGHT SE WINDS WILL PREVAIL TONIGHT WITH WINDS BECOMING GUSTY BY MID MORNING TUE. && .PREV DISCUSSION... /ISSUED 1036 PM CDT MON MAY 4 2015/ UPDATE... WEAK INVERTED TROF/ELY WAVE CONTINUES ITS TREK WEST...CURRENTLY LOCATED ROUGHLY SOUTH OF THE CAMERON/VERMILION PARISH LINE. LATEST KLCH RADAR SHOWS ISLTD SHOWERS OVER THE COASTAL WATERS EAST OF CAMERON ALONG WITH A NARROW BAND MOVING WEST ACRS THE SABINE RIVER. SHOWER CHCS SHOULD DIMINISH ACRS ERN PORTIONS OF THE AREA TONIGHT...WITH A SLT TO LOW END CHC EXPECTED MAINLY ALONG AND WEST OF A LINE FROM LEESVILLE TO LAKE CHARLES. ADJUSTED POP/WX GRIDS SLIGHTLY TO INCORPORATE RECENT HRRR GUIDANCE. ALSO TWEAKED HOURLY WINDS AS WELL AS TEMP AND DEWPOINT GRIDS...ACCOUNTING FOR RECENT OBSERVATIONS. REMAINDER OF FCST IS IN OTHERWISE DECENT SHAPE AND UPDATES HAVE BEEN SENT. 24 PREV DISCUSSION... /ISSUED 706 PM CDT MON MAY 4 2015/ DISCUSSION... 05/00Z TAF ISSUANCE. AVIATION... ISLTD SHRA/TSRA AND BKN VFR CIGS ACCOMPANY A WEAK INVERTED TROF CROSSING SRN LA AND THE NRN GULF OF MEXICO. THIS TROF WILL CROSS THE REGION TONIGHT INTO TUESDAY MORNING...WITH THE MAIN AXIS OF CLOUDS/SHRA SHIFTING WEST. ACTIVITY EXPECTED TO DIMINISH THIS EVENING THEN INCREASE LATE TONIGHT...MAINLY NEAR LCH/BPT...AS SHOWERS OR STORMS MOVE INLAND OFF THE GULF. OTHERWISE...EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE PERIOD AT LFT/ARA/AEX WITH MVFR CIGS DEVELOPING AT LCH/BPT AFTER MIDNIGHT. SELY WINDS 5-10 KT TONIGHT WILL STRENGTHEN 10-15 KT TUESDAY MORNING WITH GUSTS TO 25 KT AT TIMES DURING THE DAY. 24 PREV DISCUSSION... /ISSUED 350 PM CDT MON MAY 4 2015/ DISCUSSION... NORTH-SOUTH ORIENTED INVERTED SFC TROF...OR EASTERLY WAVE...STRETCHES ROUGHLY ALONG THE ATCHAFALAYA RIVER AND ON OUT INTO THE CENTRAL GULF OF MEXICO AS OF 20Z. THIS FEATURE HAS ASSISTED WITH THE DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OVER PARTS OF SOUTH AND EAST CENTRAL LOUISIANA THIS AFTERNOON. THE WAVE IS PROGGED TO CONTINUE WWD TONIGHT...WITH A GENERAL DECREASE IN BOTH COVERAGE AND INTENSITY OF CONVECTION EXPECTED THIS EVENING WITH THE LOSS OF DIURNAL INSTABILITY. AN UPTICK IS LIKELY OVER THE GULF WATERS AFTER MIDNIGHT AND TWD THE EARLY MORNING HRS WITH THE MARINE DMAX...WITH THE NWD CELL MOTION LEADING TO AT LEAST SOME ACTIVITY SPREADING INLAND. POPS WERE RAISED OVER EAST TX TOMORROW AS THE WAVE ENTERS A REGION OF INCREASED UPPER DIVERGENCE AND DEEPER MSTR...WITH COVERAGE EXPECTED TO EXCEED THAT OBSERVED TODAY. PATTERN THEREAFTER MARKED BY A SW TO NE RIDGE AXIS OVERHEAD...WITH A MOIST SOUTHERLY LOW LEVEL FLOW AND SUBTLE IMPULSES EJECTING AHEAD OF A DIGGING WRN CONUS TROF. LOW END POPS...WITH A GRADIENT THAT GENERALLY DECREASES FROM WEST TO EAST...ALONG WITH SEASONAL HIGHS AND ABOVE NORMAL LOWS WILL RESULT. THE TROF IS PROGGED TO EDGE EASTWARD OVER THE WEEKEND...SLOWLY ERODING THE RIDGE ALOFT...THEN FINALLY LIFTING OUT INTO THE CENTRAL CONUS AND FLATTENING IT OUT EARLY NEXT WEEK. GLOBAL MODELS ALSO PROG A FRONTAL BOUNDARY INTO THE REGION ON SUN NIGHT INTO MON. 13 MARINE... WINDS AND SEAS WILL INCREASE TONIGHT INTO TUESDAY AS THE PRESSURE GRADIENT TIGHTENS WHILE AN EASTERLY WAVE MOVES WEST ACROSS THE NORTHERN GULF. ELEVATED WINDS AND SEAS WILL CONTINUE INTO TUESDAY NIGHT...SUBSIDING ON WEDNESDAY AS THE PRESSURE GRADIENT RELAXES. THE CHANCE OF SHOWERS WILL INCREASE AS THE EASTERLY WAVE MOVES ACROSS THE REGION TODAY AND TUESDAY. && .PRELIMINARY POINT TEMPS/POPS... AEX 63 81 62 83 / 10 10 10 10 LCH 67 80 66 82 / 30 30 10 20 LFT 65 81 64 83 / 10 10 10 20 BPT 68 80 69 82 / 40 50 10 20 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 1 AM CDT WEDNESDAY FOR GMZ452-455-470- 472-475. SMALL CRAFT EXERCISE CAUTION THROUGH LATE TUESDAY NIGHT FOR GMZ450. && $$ AVIATION...05
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
504 AM EDT TUE MAY 5 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 503 AM EDT TUE MAY 5 2015 WV IMAGERY AND RUC ANALYSIS INDICATED CONFLUENT WRLY MID/UPPER LEVEL FLOW INTO THE NRN GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE SE CONUS INTO THE CNTRL PLAINS. WITH A SFC RIDGE EXTENDING FROM NW ONTARIO THROUGH THE NRN LAKES...LIGHT WINDS AND CLEAR SKIES OVER UPPER MI HAS ALLOWED TEMPS TO DROP OFF INTO THE MID AND UPPER 30S WITH SEVERAL INLAND COLD SPOTS IN THE UPPER 20S TO AROUND 30. CLOUDS AND TODAY...EXPECT THAT HIGH PRES WILL CONTINUE TO DOMINATE AS THE CLOUDS AND PCPN ASSOCIATED WITH A FRONTAL BOUNDARY FROM SRN IA INTO NRN IL REMAIN WELL TO THE SOUTH. MIXING TO 5K FT WITH 850 MB TEMPS FCST IN THE 6C TO 8C RANGE WILL SUPPORT HIGHS IN THE UPPER 60S TO AROUND 70...EXCEPT ALONG THE GREAT LAKES WHERE READING WILL REMAIN IN THE UPPER 50S AND LOWER 60S. SIMILAR TO MONDAY...AFTERNOON DEWPOINTS WILL DROP INTO THE LOWER 20S WITH RH VALUES FROM 15 TO 20 PCT. HOWEVER...WINDS WILL REMAIN LIGHT...AOB 10 MPH. TONIGHT...AS THE HIGH SHIFTS OFF TO THE EAST AND AND 850 MB WARM FRONT APPROACHES FROM THE SOUTH...EXPECT INCREASING CLOUDS OVERNIGHT. THIS WILL KEEP TEMPS FROM FALLING OFF AS MUCH WITH MIN READINGS IN THE UPPER 30S TO AROUND 40. WITH THE VERY DRY AIRMASS IN PLACE...THE SLOWER END OF GUIDANCE WAS FAVORED WITH THE PCPN ADVANCING FROM THE SOUTH. SO...NO PCPN MENTION WAS INCLUDED. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 438 AM EDT TUE MAY 5 2015 ABOVE AVERAGE TEMPS WILL CONTINUE THROUGH THE WEEK AMIDST SMALL CHANCES OF PRECIP WEDNESDAY...AND A CHANCE OF SHOWERS AND STORMS LATE THURSDAY INTO FRIDAY. MUCH COOLER WEATHER WILL THEN RETURN FOR THE WEEKEND. WEDNESDAY AND WEDNESDAY NIGHT...A STOUT MID-LEVEL RIDGE WILL BE ENTERING THE WESTERN CWA AT 12Z WED AS AN ASSOCIATED SFC HIGH OVER GEORGIAN BAY SHIFTS SOUTHEASTWARD. MEANWHILE...A SHORTWAVE TROUGH DRIFTING NE FROM THE SOUTHERN ROCKIES WILL BEGIN TO CONSOLIDATE A BROAD SFC TROUGH ALONG THE ENTIRE U.S. ROCKIES. MODELS CONTINUE THEIR TWO-DAY TREND IN LOWERING QPF ALONG AN 850 HPA WARM FRONT ACROSS THE SW CWA WED MORNING. IN FACT...MOST OF THE HIGHER-RES GUIDANCE SUITE SHOWS VERY LITTLE PRECIP DURING THE DAY WEDNESDAY. THE STEEP MID-LEVEL RIDGE IS PROVING TO BE TOO MUCH TO MAINTAIN MOST OF THE INCOMING RAIN SHOWERS FROM WI. ADDITIONALLY...THE BULK OF THE BETTER LOW-LEVEL MOISTURE WILL REMAIN ACROSS MN. HAVE THUS OPTED TO CUT NEARLY ALL CHANCES OF PRECIP EXCEPT FOR A SLIGHT CHANCE FOR SHOWERS ALONG THE WI BORDER IN THE MORNING. THURSDAY THROUGH FRIDAY...AFTER THE H8 WARM FRONT CROSSES THE CWA...THERE IS LITTLE SUPPORT FOR PRECIP UNTIL AT LEAST THURSDAY AFTERNOON. ADDITIONALLY...CAPPING AROUND 750 HPA SHOULD KEEP PRECIP CHANCES LIMITED THROUGH THURSDAY MORNING. THE SFC COLD FRONT UNDER INCREASING MOISTURE FROM AN H8 50KT JET AND A DEVELOPING LEFT-EXIT OF A WEAK UPPER JET STREAK SHOULD BE ENOUGH TO RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS LATE THU AFTERNOON THROUGH MUCH OF THU NIGHT. HOWEVER...KEPT POPS AT JUST A CHANCE OF SHOWERS AND THUNDERSTORMS AS THE BEST MID-LEVEL FORCING PEELS OFF TO THE NORTH. TEMPS COULD GET QUITE WARM THU IF ENOUGH AFTERNOON CLEARING OCCURS. GIVEN THE CAP...THINK THERE WILL BE ENOUGH INSOLATION TO BOOST TEMPS INTO THE LOW 80S ACROSS THE WEST UNDER H8 TEMPS UP TO 14C. IN ADDITION TO THE WARMER WX...MIXING INTO 35 TO 45KT WINDS SHOULD RESULT IN QUITE A GUSTY DAY...ESPECIALLY WEST. EVEN THOUGH MUCH OF WEST DID NOT BENEFIT FROM SATURDAYS PRECIP...FIRE WX CONCERNS SHOULD BE PARTIALLY MITIGATED BY INCREASING LOW-LEVEL MOISTURE...RESULTING IN MIN RH VALUES ONLY INTO THE UPPER 30S. HOWEVER...FIRE INDICES ARE BEGINNING TO INDICATE INCREASING FIRE POTENTIAL ACROSS THE WEST...SO THURSDAY WILL NEED TO BE MONITORED IF LOW-LEVEL MOISTURE IS SLOW TO ARRIVE. FRIDAY...THE COLD FRONT LOOKS TO CLEAR THE CWA BY FRIDAY AFTERNOON...ENDING PRECIP CHANCES AND USHERING IN COOLER AIR. TEMPS WILL DROP ALONG PORTIONS OF LAKE SUPERIOR DURING THE AFTERNOON HOURS AS WINDS BECOME NW. SATURDAY...THE ECMWF AND CANADIAN GEM STRUGGLE TO PUSH THE COLD FRONT FAR AWAY FROM THE CWA...LEAVING LINGERING CHANCES OF SHOWERS ACROSS THE SE HALF. THE GFS KEEPS THE AREA DRY...AND GIVEN ITS BETTER RUN TO RUN CONSISTENCY WITH THIS SYSTEM...HAVE OPTED TO KEEP NEARLY ALL POPS OUT OF THE CWA. HOWEVER...SOME SPRINKLES/DRIZZLE CANNOT BE RULED OUT ALONG LAKE SUPERIOR...WHERE N WINDS AND LINGERING LOW-LEVEL MOISTURE SHOULD RESULT IN DECENT LOW-LEVEL CLOUDS. ADDITIONALLY...TEMPS WILL LIKELY STRUGGLE TO REACH 50F NEAR THE SHORE. SUNDAY AND MONDAY...MODEL DIFFERENCE QUICKLY DEVELOP WITH THE HANDLING OF A DEEP TROUGH EXITING THE WESTERN CONUS. FOLLOWING THE GFS SOLUTION...A SFC LOW IN THE LEE OF THE ROCKIES WILL TRACK ENE ALONG THE STALLED W TO E SFC BOUNDARY BIFURCATING THE CENTRAL CONUS. THE ECMWF AND CANADIAN GEM TRACK THE LOW FARTHER NORTH. ABUNDANT CONVECTION ACROSS THE PLAINS ONLY LEADS TO MORE UNCERTAINTY WITH THE SYNOPTIC EVOLUTION OF THIS SYSTEM...SO HAD TO RESORT TO USING CONSENSUS CHANCE POPS SUNDAY AFTERNOON THROUGH MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 135 AM EDT TUE MAY 5 2015 WITH DRY HI PRES DOMINATING...EXPECT VFR CONDITIONS AND LIGHT WINDS AT ALL 3 TAF SITES THIS FCST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 503 AM EDT TUE MAY 5 2015 AS A TROUGH MOVES FROM THE PLAINS TO THE UPPER MS VALLEY...SRLY WINDS WILL INCREASE TO AROUND 25 KNOTS OVER THE EAST BY LATE THU INTO THU NIGHT. OTHERWISE...WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS BILLINGS MT
354 AM MDT TUE MAY 5 2015 .SHORT TERM...VALID FOR TDY AND WED... UNSETTLED WEATHER BEGINS TODAY AND WILL CONTINUE RIGHT THROUGH THE REMAINDER OF THE WEEK. AN UPPER LOW AND TROUGH WILL MOVE ONTO THE PACIFIC NORTHWEST COAST TODAY AND REMAIN STATIONARY OR SLOWLY SHIFT SOUTHEAST TOWARD THE GREAT BASIN AREA DURING THE DAY WEDNESDAY. THIS WILL ALLOW A SOUTHWEST FLOW ALOFT TO BEGIN TO DEVELOP OVER OUR AREA TODAY AND ESPECIALLY BE IN PLACE FOR WEDNESDAY. SEVERAL SURFACE LOWS WILL DEVELOP ACROSS THE NORTHERN AND CENTRAL ROCKIES BRINGING A PREDOMINATELY SOUTHEAST SURFACE FLOW ALLOWING FOR INCREASING LOW-LEVEL MOISTURE ACROSS THE AREA THROUGH WEDNESDAY. MODELS INCLUDING THE HRRR BRING A VORT MAX OVER OUR AREA TODAY RESULTING IN SHOWERS AND ISOLATED THUNDERSTORMS. SHEAR IS A BIT BETTER TODAY BUT STILL NOT IMPRESSIVE. CAPES ARE ALSO SLIGHTLY BETTER TODAY AND MORE WIDESPREAD SO THUNDERSTORM CHANCES WILL BE BETTER TODAY THAN TUESDAY. PRE-FRONTAL WARMING TODAY WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 70S TO AROUND 80 DEGREES. A COLD FRONT WILL MOVE ACROSS THE FORECAST AREA WEDNESDAY MORNING USHERING IN GUSTY NORTHWEST WINDS BY AFTERNOON ALONG WITH A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS. TEMPERATURES WILL BE MUCH COOLER WITH READINGS ONLY IN THE LOWER TO MIDDLE 60S SO INSTABILITY FOR THUNDERSTORMS WILL NOT BE AS GOOD AS TODAY. A STRONGER DISTURBANCE AND UPPER LOW WILL MOVE NORTHEAST OUT OF WYOMING WEDNESDAY INTO WEDNESDAY NIGHT. MODELS SHOW GOOD WRAP- AROUND MOISTURE WITH THIS ALONG WITH DECENT QPF AMOUNTS. AS A RESULT...HAVE INCREASED POPS INTO THE LIKELY AND CATEGORICAL RANGE DURING THIS TIME FROM CUSTER AND POWDER RIVER COUNTIES EASTWARD. ELSEWHERE...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS. HOOLEY .LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON... LATEST MODEL RUNS HAVE CONTINUED TO KEEP THE BULK OF THE ENERGY AND MOISTURE OUT OF THE THE AREA. MODELS HAVE CONTINUED TO TRACK WELL WITH EACH OTHER...WITH THE 00Z DATA HAVING MORE OF A CLOSED LOW EJECTING FROM THE GREAT BASIN THIS WEEKEND...BUT IT TRACKS MORE INTO THE CENTRAL PLAINS. THIS HAS THE EFFECT OF KEEPING THE BULK OF THE MOISTURE AND ENERGY SOUTH OF MONTANA. CONTINUE TO SEE DIFFLUENT FLOW ALOFT ACROSS THE AREA THIS WEEKEND...ALONG WITH SOME MID-LEVEL MOISTURE. THIS WILL KEEP AT LEAST A CHANCE OF LIGHT SCATTERED PRECIP ACROSS THE AREA. HAVE TRENDED POPS DOWN SOME GIVEN THE TREND AWAY FROM A MORE FAVORABLE SOLUTION. THE COLUMN IS NOT OVERLY SATURATED...WITH PRECIPITABLE WATER VALUES ONLY AROUND A HALF INCH. THE POTENTIAL FOR MUCH ACCUMULATION REMAINS LOW. WITH THE MID LEVEL MOISTURE...MUCH OF THE EXTENDED PERIOD WILL BE CLOUDY...THUS COOLER. TEMPERATURES CONTINUE BE IN THE 50S FOR HIGHS. REIMER && .AVIATION... VFR CONDITIONS EXPECT THROUGH MUCH OF THE NEXT 24. SOME SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS AND WILL MOVE EAST IN THE ADJACENT PLAINS. LATEST HIRES MODELS SHOW ACTIVITY STAYING WEST OF BILLINGS...LIMITING MOST THUNDERSTORM ACTIVITY TO LIVINGSTON AND SHERIDAN. LOW LEVEL WIND SHEER WILL CONTINUE AROUND MILES CITY UNTIL AROUND MID MORNING BEFORE SURFACE WIND BEGIN TO INCREASE. REIMER && .PRELIMINARY POINT TEMP/POPS... TDY WED THU FRI SAT SUN MON ------------------------------------------------------- BIL 079 049/059 040/053 040/053 039/051 038/059 040/060 2/T 43/W 22/W 24/W 55/W 43/W 32/W LVM 076 043/061 036/050 034/048 034/050 034/059 035/060 3/T 64/W 35/W 35/W 55/W 43/W 33/W HDN 082 050/061 042/056 038/057 039/053 037/059 035/062 1/B 34/W 22/W 23/W 55/W 43/W 32/W MLS 079 051/060 041/055 037/056 038/054 037/057 038/061 1/U 38/W 42/W 12/W 44/W 43/W 32/W 4BQ 075 051/061 043/055 035/055 039/052 035/053 034/059 1/B 48/T 42/W 12/W 55/W 44/W 32/W BHK 073 050/060 042/054 034/054 035/052 034/054 031/057 1/N 39/T 72/W 12/W 44/W 33/W 22/W SHR 075 048/054 037/053 035/054 038/050 035/051 032/058 2/T 45/W 43/W 34/W 55/W 54/W 33/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
327 AM MDT TUE MAY 5 2015 .SYNOPSIS... ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AS AN UPPER LEVEL DISTURBANCE PASSES OVERHEAD. THE STRONGEST STORMS WILL BE FOUND ACROSS THE FAR EASTERN PLAINS WHERE LARGE HAIL...DAMAGING WINDS AND HEAVY RAIN WILL BE A CONCERN. AFTER TODAY...MAINLY DRY AND WINDY CONDITIONS ARE IN STORE THROUGH FRIDAY. HOWEVER...A FEW THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON ACROSS THE FAR EASTERN PLAINS ALONG THE DRYLINE. THE NEXT STORM SYSTEM LOOKS TO CROSS THE STATE ON SATURDAY...WHICH MAY INCREASE PRECIPITATION CHANCES ACROSS THE WEST. OTHERWISE... TEMPERATURES WILL REMAIN NEAR TO BELOW NORMAL FOR THE NEXT SEVEN DAYS. && .DISCUSSION... SHOWERS AND A FEW THUNDERSTORMS CONTINUE THIS MORNING ACROSS EASTERN NM AHEAD OF UPPER LEVEL LOW WHICH IS NOW CENTERED IN THE VICINITY OF FLAGSTAFF. THIS CURRENT ACTIVITY SHOULD LARGELY PUSH EAST OF THE TEXAS BORDER BY 12-14Z AND ALLOW FOR A SHORT BREAK BEFORE THE NEXT ROUND BEGINS. WITH STRONG FORCING AND LITTLE TO NO INHIBITION... STORMS SHOULD DEVELOP EARLY...PERHAPS BY 17Z...ALONG OR JUST EAST OF HIGHER TERRAIN AND/OR ALONG REMNANT BOUNDARIES. BEST INSTABILITY REMAINS ACROSS THE FAR EASTERN PLAINS WHERE CAPE VALUES MAY APPROACH 2000 J/KG. THUS STORMS MAY INITIATE NEAR THE CENTRAL MTN CHAIN...BUT INCREASE IN STRENGTH AS THEY MOVE INTO BETTER MOISTURE AND INSTABILITY. LOW LEVEL WINDS LOOK TO VEER TO AROUND TO THE SW BY EARLY AFTERNOON AS THE TROUGH AXIS MOVES EASTWARD AND DRIER WESTERLY FLOW MOVES INTO THE AREA. PRIOR TO THE DRY AIR MOVING IN...PWATS WILL REMAIN NEAR 1 INCH...OR BETTER THAN 200 PERCENT OF NORMAL FOR THIS TIME OF YEAR. THUS...A HEAVY RAIN THREAT WILL CONTINUE TO EXIST WITH THESE STORMS. AREAS THAT HAVE ALREADY RECEIVED SIGNFICANT AMOUNTS OF RAIN WILL BE THE MOST SUSCEPTIBLE TO ADDITIONAL FLOODING. THIS INCLUDES THE CLOVIS AREA WHERE UP TO 5 INCHES OF RAIN FELL YESTERDAY. THE FLASH FLOOD WATCH REMAINS INTACT THROUGH 00Z AND ANY SEVERE WEATHER IS MOST LIKELY TO OCCUR BETWEEN NOON AND 6PM. MEANWHILE ACROSS WESTERN AND CENTRAL NM...ANOTHER ROUND OF SCATTERED TO NUMEROUS THUNDERSTORMS WILL DEVELOP. THIS AREA WILL BE UNDER THE COLD CORE OF THE LOW...THUS A FEW STORMS MAY CONTAIN SOME SMALL HAIL AND HEAVY RAIN. A COLD CORE FUNNEL IS ALSO NOT OUT OF THE QUESTION. BRIEF SHORTWAVE RIDGING WILL OCCUR ON WEDNESDAY BEFORE SOUTHWESTERLY FLOW INCREASES AHEAD OF THE NEXT STORM SYSTEM. A 996 MB SURFACE LOW ACROSS SE CO WILL ALLOW FOR WINDS TO INCREASE ACROSS THE PLAINS. OTHERWISE MUCH DRIER CONDITIONS AS THE DRY SLOT MOVES OVERHEAD AND SOME DRY AIR MIXES DOWN TO THE SURFACE. BEST CHANCE FOR A FEW STORMS WILL BE ACROSS THE NW OR NC NM. THE DRYLINE WILL SLOSH BACK WESTWARD WEDNESDAY NIGHT AND THIS WILL BE A THEME FOR THE REST OF THE WEEK. THE NEXT LOW PRESSURE SYSTEM LOOKS TO DIVE MUCH FURTHER SOUTH THAN PREVIOUSLY INDICATED. IT APPEARS IT MAY ACTUALLY REMAIN A CLOSED LOW AS IT CROSSES NORTHERN NM ON SATURDAY. IF THE LOW DOES INDEED DIVE THAT FAR SOUTH...EXPECT THE DRYLINE TO RETREAT WESTWARD INTO EASTERN NM EACH NIGHT AND THEN MIX BACK EASTWARD EACH DAY. WITH THAT...WILL COME A CHANCE FOR A FEW STORMS NEAR THE TEXAS BORDER EACH AFTERNOON. ELSEWHERE...IT WILL BE MAINLY DRY AND BREEZY UNTIL SATURDAY WHEN BETTER CHANCES OF PRECIP WILL EXIST AS LOW SHIFTS OVERHEAD. 34 && .FIRE WEATHER... NO WIDESPREAD FIRE WEATHER CONCERNS THROUGH THE FORECAST PERIOD. SMALL AREAS OF MARGINAL CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE FRIDAY AND SATURDAY. IT WAS A WET MONDAY ACROSS THE FORECAST AREA...ESPECIALLY IN THE EAST. AROUND FIVE INCHES OF RAIN FELL AT THE CANNON AIR FORCE BASE. THE UPPER LOW CAUSING ALL THIS RAIN IS NOW OVER AZ. IT WILL TRACK NORTHEAST ACROSS THE FOUR CORNERS AREA TODAY. A DRY SLOT IS EVIDENT ON SATELLITE IMAGES ACROSS SOUTHWEST NM AND IT WILL CONTINUE ACROSS SOUTHERN NM TODAY. SHOWER AND THUNDERSTORM COVERAGE WILL BE LESS TODAY COMPARED TO MONDAY. BUT PLENTY OF LOW LEVEL MOISTURE IS STILL AROUND ALONG WITH A VERY UNSTABLE AIRMASS...ESPECIALLY IN THE EAST. SO ANOTHER ACTIVE DAY ON TAP WITH THE POTENTIAL FOR SEVERE STORMS NEAR THE TX BORDER. SOME OF THE RAIN WILL BE HEAVY AS WELL WITH FLASH FLOODING A CONCERN...ESPECIALLY FOR PLACES HIT HARD MONDAY. SOME OF THE STORMS WILL PRODUCE SMALL HAIL AS TEMPERATURES ALOFT WILL BE QUITE COLD FOR EARLY MAY. MIN RH VALUES WILL ONLY DROP TO BETWEEN 40 AND 60 PERCENT TODAY WHILE VENT RATES WILL BE MOSTLY EXCELLENT. A DRYING TREND REMAINS ON TRACK FOR THE REST OF THE WEEK. HIGH TEMPERATURES WILL WARM TO WITHIN SIX OR SEVEN DEGREES EITHER SIDE OF NORMAL WEDNESDAY THROUGH FRIDAY. THERE WILL STILL BE SHOWERS AND A FEW STORMS OVER THE NORTHWEST THIRD OF THE STATE WEDNESDAY AND NEAR THE TX BORDER ON THURSDAY ALONG A POTENTIAL DRYLINE. MODELS CONTINUE TO TREND FARTHER SOUTH WITH A UNSEASONABLY DEEP CLOSED LOW DROPPING SOUTH THROUGH CALIFORNIA THURSDAY INTO FRIDAY. INCREASING SOUTHWEST WINDS AHEAD OF THE STORM MAY RESULT IN A FEW HOURS OF CRITICAL CONDITIONS FOR THE LOWER RIO GRANDE VALLEY FRIDAY AFTERNOON...AND BORDERLINE CRITICAL CONDITIONS OVER A SMALL AREA OF THE EASTERN PLAINS SATURDAY. VENTILATION RATES WILL GENERALLY REMAIN IN THE GOOD TO EXCELLENT RANGE DURING THIS TIME. THE ABOVE MENTIONED STORM WILL BRING COOLER AND WETTER CONDITIONS BACK TO NM FOR FRIDAY NIGHT INTO THE WEEKEND. THE STORM SHOULD LIFT NORTHEAST INTO CO SUNDAY...BRINGING SOME DRYING AND WARMING TO THE AREA. THIS TREND WILL CONTINUE ON MONDAY. AN ACTIVE DRY LINE MIGHT SET UP TUESDAY ACROSS THE EAST. CHJ && .AVIATION... 06Z TAF CYCLE A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO STEER BANDS OF SHOWERS AND THUNDERSTORMS NORTH AND NORTHEASTWARD ACROSS N AND E PARTS OF THE FORECAST AREA THROUGH THE OVERNIGHT HOURS. THE TRUSTED HRRR MODELS DEPICTION OF DECREASING ACTIVITY ACROSS SW AND CENTRAL AREAS APPEARS TO BE COMING TRUE. AREAS OF LOW CLOUDS AND POSSIBLY SOME FOG ARE EXPECTED TO BECOME GRADUALLY MORE WIDESPREAD THROUGH THE NIGHT ACROSS MUCH OF THE PLAINS. THOUGH ITS FORMATION COULD BE A BIT PATCHY DUE TO SOME MID LEVEL CLOUD COVER. MODELS AGREE ON A DOWNTICK IN CONVECTIVE ACTIVITY TUESDAY MORNING AS LOW CLOUDS GRADUALLY BREAK UP IN THE EAST. THEN ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS IS EXPECTED IN THE AFTERNOON AND EVENING WITH HIGHEST PROBABILITIES ACROSS NORTHERN AREAS. 44 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 66 46 71 41 / 60 50 20 10 DULCE........................... 59 39 65 35 / 70 60 40 30 CUBA............................ 60 41 66 38 / 60 50 20 20 GALLUP.......................... 61 39 67 34 / 50 40 10 10 EL MORRO........................ 58 38 64 35 / 60 30 10 10 GRANTS.......................... 62 38 68 33 / 50 30 5 5 QUEMADO......................... 60 37 67 34 / 50 20 5 5 GLENWOOD........................ 69 44 74 42 / 30 10 0 5 CHAMA........................... 58 36 59 31 / 70 60 40 20 LOS ALAMOS...................... 60 44 67 44 / 70 40 20 10 PECOS........................... 58 43 65 42 / 70 30 10 10 CERRO/QUESTA.................... 60 38 64 34 / 70 40 20 20 RED RIVER....................... 50 35 52 31 / 70 50 30 20 ANGEL FIRE...................... 54 35 58 28 / 70 40 20 10 TAOS............................ 61 38 65 34 / 60 40 20 10 MORA............................ 57 42 64 39 / 70 30 10 10 ESPANOLA........................ 63 45 71 43 / 60 30 10 10 SANTA FE........................ 60 44 66 42 / 60 30 10 5 SANTA FE AIRPORT................ 65 43 70 40 / 60 30 10 5 ALBUQUERQUE FOOTHILLS........... 67 48 73 47 / 40 30 5 5 ALBUQUERQUE HEIGHTS............. 69 49 74 50 / 40 20 0 5 ALBUQUERQUE VALLEY.............. 70 47 76 46 / 40 20 0 5 ALBUQUERQUE WEST MESA........... 69 48 75 47 / 40 30 0 5 LOS LUNAS....................... 71 47 78 45 / 30 20 0 5 RIO RANCHO...................... 67 49 74 48 / 50 30 5 5 SOCORRO......................... 71 49 79 48 / 30 20 0 5 SANDIA PARK/CEDAR CREST......... 64 44 71 44 / 50 40 10 5 TIJERAS......................... 66 44 73 44 / 40 30 5 5 MORIARTY/ESTANCIA............... 64 40 69 37 / 40 20 0 5 CLINES CORNERS.................. 63 41 68 40 / 50 20 0 5 GRAN QUIVIRA.................... 65 44 70 44 / 40 20 0 5 CARRIZOZO....................... 69 48 74 48 / 20 10 0 5 RUIDOSO......................... 65 45 71 45 / 30 10 0 5 CAPULIN......................... 61 44 69 43 / 70 30 10 10 RATON........................... 64 42 72 40 / 70 20 5 10 SPRINGER........................ 65 44 74 41 / 60 20 5 5 LAS VEGAS....................... 61 44 69 39 / 60 20 5 5 CLAYTON......................... 64 47 79 48 / 80 30 5 5 ROY............................. 64 46 73 44 / 60 20 5 5 CONCHAS......................... 70 52 79 50 / 60 20 0 5 SANTA ROSA...................... 70 50 78 48 / 60 20 0 5 TUCUMCARI....................... 72 53 81 51 / 70 20 0 5 CLOVIS.......................... 71 49 78 51 / 70 20 0 10 PORTALES........................ 72 51 79 52 / 70 20 0 10 FORT SUMNER..................... 72 51 80 51 / 60 20 0 5 ROSWELL......................... 79 51 84 50 / 30 10 0 5 PICACHO......................... 73 49 79 49 / 30 10 0 5 ELK............................. 68 47 74 47 / 30 10 0 5 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR THE FOLLOWING ZONES... NMZ535>538. && $$ 34
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1154 PM MDT MON MAY 4 2015 .AVIATION... 06Z TAF CYCLE A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO STEER BANDS OF SHOWERS AND THUNDERSTORMS NORTH AND NORTHEASTWARD ACROSS N AND E PARTS OF THE FORECAST AREA THROUGH THE OVERNIGHT HOURS. THE TRUSTED HRRR MODELS DEPICTION OF DECREASING ACTIVITY ACROSS SW AND CENTRAL AREAS APPEARS TO BE COMING TRUE. AREAS OF LOW CLOUDS AND POSSIBLY SOME FOG ARE EXPECTED TO BECOME GRADUALLY MORE WIDESPREAD THROUGH THE NIGHT ACROSS MUCH OF THE PLAINS. THOUGH ITS FORMATION COULD BE A BIT PATCHY DUE TO SOME MID LEVEL CLOUD COVER. MODELS AGREE ON A DOWNTICK IN CONVECTIVE ACTIVITY TUESDAY MORNING AS LOW CLOUDS GRADUALLY BREAK UP IN THE EAST. THEN ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS IS EXPECTED IN THE AFTERNOON AND EVENING WITH HIGHEST PROBABILITIES ACROSS NORTHERN AREAS. 44 && .PREV DISCUSSION...1027 PM MDT MON MAY 4 2015... .UPDATE... RATHER MODEST UPDATE TO LOWER POPS SOME ACROSS PARTS OF THE WEST AND FAR NE FOR REST OF PRE MIDNIGHT PERIOD...BUT NOT MANY CHANGES AFTER MIDNIGHT. LOWERED QPF SHARPLY FOR REST OF PRE MIDNIGHT PERIOD DUE MOST TO THERE BEING UNDER TWO HOURS LEFT TIL THEN...BUT ALLOWED FOR RADAR TRENDS AS WELL. DROPPED LOW TEMPS A DEGREE OR TWO PORTIONS OF CENTRAL NM AND IMMEDIATELY ADJACENT LOCALES...ALSO FAR NW. FAR E CENTRAL NM...WHERE MOST OF REPORTED SIGNIFICANT FLOODING HAS OCCURRED WILL BE SEEING MUCH LESS INTENSE OFF AND ON RAIN REST OF THE NIGHT. 43 && .PREV DISCUSSION...330 PM MDT MON MAY 4 2015... .SYNOPSIS... SHOWERS AND THUNDERSTORMS WILL CONTINUE TO IMPACT THE STATE THROUGH TUESDAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM...CURRENTLY OVER ARIZONA...MOVES SLOWLY EAST ACROSS THE REGION. MOST AREAS WILL SEE GOOD CHANCES FOR WETTING RAINS...BUT LOCALES BETWEEN THE CENTRAL MOUNTAIN CHAIN AND THE TEXAS BORDER WILL HAVE THE BEST CHANCES WITH THE POTENTIAL FOR FLASH FLOODING AND SOME HAIL. LOOK FOR MOSTLY DRY...WARM AND BREEZY TO LOCALLY WINDY CONDITIONS TO PREVAIL FROM WEDNESDAY THROUGH SATURDAY AS ANOTHER UPPER LEVEL LOW PRESSURE SYSTEM GRADUALLY APPROACHES FROM THE WEST. TEMPERATURES WILL TREND DOWN OVER THE WEEKEND AS THE UPPER LEVEL LOW PRESSURE SYSTEM PUSHES A PACIFIC COLD FRONT THROUGH. && .DISCUSSION... MOISTURE ADVECTION AND DESTABILIZATION OF THE ATMOSPHERE WITH THE APPROACH OF THE UPPER LOW...CURRENTLY OVER ARIZONA...IS RESULTING IN THUNDERSTORMS BREAKING-OUT ACROSS MUCH OF THE AREA. THROUGH 3 PM MDT...THE MOST ROBUST THUNDERSTORMS HAVE BEEN ACROSS THE EASTERN PLAINS WHERE SEVERAL REPORTS OF HAIL UP TO QUARTER SIZE AND RAIN AMOUNTS IN EXCESS OF ONE INCH IN 30 MINUTES HAVE BEEN REPORTED. MOISTURE ADVECTION IS FORECAST TO CONTINUE INTO THE EVENING HOURS...WITH PWATS EXCEEDING ONE INCH ACROSS SOUTHEAST PORTIONS OF OUR AREA WHICH WOULD BE NEAR THE 99TH PERCENTILE IN TERMS OF MAY PWAT CLIMATOLOGY. AT THIS POINT...THE FLASH FLOOD THREAT WOULD APPEAR LIMITED...BUT SOME MERGING/ORGANIZATION OF STORMS IS FORECAST TO OCCUR OVERNIGHT AND WILL INCREASE THE FLASH FLOOD THREAT OVER THE WATCH AREA. ELSEWHERE...THE FLASH FLOOD THREAT SHOULD BE LOCALIZED...THOUGH SOAKING RAINS ARE LIKELY ACROSS CENTRAL AND NORTHERN PORTIONS OF NEW MEXICO. ANOTHER HEALTHY ROUND OF STORMS FORECAST TUESDAY AS THE UPPER LOW MOVES OVERHEAD...WITH THE BEST CHANCES FOR DEEP...PERHAPS SEVERE..CONVECTION NEAR THE TEXAS BORDER WHERE THE SPC SHOWS A SLIGHT RISK FOR SEVERE STORMS IN THE DAY 2 CONVECTIVE OUTLOOK. THAT SAID...CONVECTION IS FORECAST TO SHIFT RAPIDLY INTO THE TEXAS PANHANDLE TUESDAY AFTERNOON...SO THE SEVERE THREAT MAY BE LIMITED TO A FEW HOURS DURING THE AFTERNOON. ELSEWHERE...HAIL-PRODUCING STORMS ARE FORECAST BY AFTERNOON...ESPECIALLY IN THE MOUNTAINS... WITH THE POTENTIAL FOR SEVERAL INCHES OF HAIL ACCUMULATION THOUGH ACTUAL HAIL SIZE SHOULD BE LESS THAN ONE INCH. TUESDAY WILL BE A "COOL" DAY WITH HIGHS BELOW NORMAL AREAWIDE. A DRYING/WARMING TREND TO KICK-OFF WEDNESDAY AND CONTINUE THROUGH THE END OF THE WORK WEEK WITH BREEZY TO LOCALLY WINDY CONDITIONS. A FEW SHOWERS AND THUNDERSTORMS ARE FORECAST EACH DAY...MAINLY ACROSS THE WESTERN AND NORTHERN HIGH TERRAIN...BUT GIVEN A SIGNIFICANT DOWNTREND IN PWATS WETTING RAINS WILL BE HARD TO COME- BY. SOME POTENTIAL EXISTS FOR A DRYLINE THUNDERSTORM OR TWO BETWEEN WEDNESDAY NIGHT AND FRIDAY ACROSS THE FAR SOUTHEAST... DEPENDENT ON THE EXTENT OF THE DRYLINE SLOSHING WESTWARD. A COOLING TREND FORECAST OVER THE WEEKEND AS THE EASTWARD ADVANCING UPPER LOW PUSHES A PACIFIC COLD FRONT THROUGH. THE 12Z MODEL SUITE TRENDED FURTHER SOUTH WITH THE BOTTOMING OF THE UPPER LOW LATER THIS WEEK AND PUSHES IT FURTHER EAST BEFORE PULLING IT OUT TO THE NORTHEAST COMPARED TO PREVIOUS RUNS. IF THIS TREND CONTINUES THEN THIS FEATURE MAY BE MORE OF A WEATHER-MAKER FOR US THAN WHAT IS CURRENTLY IN OUR FORECAST. 11 && .FIRE WEATHER... ATMOSPHERIC LIFT ASSOCIATED WITH UPPER LOW/TROUGH OVER WESTERN ARIZONA DRAWING UP PLENTIFUL MID LEVEL SUBTROPICAL MOISTURE TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS OVER MUCH OF THE AREA. LOW LEVEL GULF MOISTURE SURGED NORTHWARD LAST NIGHT AND THIS MORNING ON A LOW LEVEL JET CENTERED OVER FAR WEST TX AND SE NM. SHOWERS AND STORMS WILL CONTINUE WELL INTO THE EVENING HOURS AS LIFT AHEAD OF THE UPPER LOW REMAINS OVER NEW MEXICO. STRONG TO SEVERE STORMS OVER THE EASTERN PLAINS WILL CONTINUE OVERNIGHT. HEAVY RAINFALL AMOUNTS ARE LIKELY OVER THE EAST-CENTRAL AND SOUTHEAST PLAINS. ABOVE MENTIONED UPPER LOW/TROUGH SLIDES NORTHEASTWARD TO NEAR THE FOUR CORNERS BY TUESDAY MORNING. COLD POOL OF AIR ALOFT WILL COMBINE WITH DAYTIME HEATING AND RESIDUAL MOISTURE TO GENERATE ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MAY OF THE STORMS WILL LIKELY PRODUCE SMALL HAIL AS TEMPERATURES ALOFT WILL BE QUITE COLD FOR EARLY MAY. WIDESPREAD WETTING RAINS REMAIN ON TRACK BETWEEN THIS AFTERNOON AND TUESDAY EVENING OVER MUCH OF CENTRAL AND NORTHERN NEW MEXICO. DRIER BUT COOLER THAN AVERAGE TEMPERATURES REMAIN ON TRACK FOR WEDNESDAY. WEATHER PREDICTION MODELS ARE IN GOOD AGREEMENT THAT LOW LEVEL SOUTHERLY WINDS WILL INCREASE THURSDAY...RESULTING IN SLIGHT WARMING. MODELS ARE TRENDING FARTHER SOUTH WITH A UNSEASONABLY DEEP CLOSED LOW DROPPING SOUTH THROUGH CALIFORNIA WEDNESDAY NIGHT AND THURSDAY. ANY FARTHER SOUTH AND THE FLOW ALOFT COULD BACK ENOUGH TO DRAW UP SUBTROPICAL MOISTURE ONCE AGAIN...RESULTING IN MORE PRECIPITATION THAN WIND. AT THIS TIME...HOWEVER...CURRENT MODEL SOLUTIONS WOULD RESULT IN INCREASING SOUTHWEST WINDS AND A FEW HOURS OF CRITICAL CONDITIONS FOR THE LOWER RIO GRANDE VALLEY FRIDAY AFTERNOON. VENTILATION RATES WILL GENERALLY BE IN GOOD TO EXCELLENT RANGE DURING THE NEXT SEVEN DAYS. 33 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES...NMZ535>538. && $$
AREA FORECAST DISCUSSION
NWS NORMAN OK
340 AM CDT TUE MAY 5 2015 .DISCUSSION... PRIMARY FORECAST CONCERN THIS MORNING IS FOCUSED ON TODAY THROUGH WEDNESDAY THUNDERSTORM CHANCES. HOWEVER... THUNDERSTORM CHANCES WILL CONTINUE NEAR DAILY THROUGH THE WEEKEND. CURRENTLY... CONVECTION ACROSS WEST TEXAS... ALONG AND EAST OF THE LLANO ESTACADO... CONTINUES... WITH THE SFC LOW SLOWLY EVOLVING ACROSS THE BIG BEND OF TEXAS. THROUGH MIDNIGHT... NEARLY 4 TO 5 INCHES OF RAIN HAD FALLEN ACROSS PORTIONS OF WEST TEXAS. EXPECT THE SFC LOW TO SLOWLY LIFT N/NE ACROSS FAR WEST TEXAS... WITH SHOWERS AND THUNDERSTORMS CONTINUING TO MOVE NWRD ACROSS THE W TX AND THE PANHANDLES INTO WRN N TX AND FAR WRN OK THROUGH SUNRISE. MESOSCALE GUIDANCE IS IN GOOD AGREEMENT... ALTHOUGH THE HRRR MIGHT BE A TAD BULLISH WITH THE EWRD EXTENT OF PRECIP INTO OK THROUGH MID MORNING. SHOWERS AND THUNDERSTORMS CHANCES WILL SLOWLY INCREASE ACROSS WRN OK AND WRN N TX THROUGH THE AFTN. LOCALLY HEAVY RAINFALL MAY BE AN ISSUE LATER THIS MORNING/THIS AFTN AS BANDING MAY DEVELOP ALONG THE ERN PANHANDLES/WRN OK... WHERE THE BETTER ISENTROPIC RESPONSE MAY SET UP ON THE ERN PERIPHERY OF THE H500 LOW. WITH GOOD MID-LEVEL ASCENT AND A NARROW BAND OF MUCAPE VALUES OF 600 TO 900 J/KG... WOULD NOT BE SURPRISED TO SEE SOME LOCALLY HIGHER RAINFALL GREATER THAN 1 INCH THROUGH THE DAY. THE NAM IS THE MOST AGGRESSIVE WITH QPF... SO IT WILL BE INTERESTING TO SEE HOW TODAY UNFOLDS. AS FOR STRONG TO SEVERE STORMS TODAY... THE BEST CHANCE WILL BE LATE THIS AFTN/EVENING ACROSS FAR W/SWRN OK AND WRN N TX. OF COURSE... ANY STORM DEVELOPMENT WILL BE HIGHLY DEPENDENT ON WHAT HAPPENS THIS MORNING AND AFTN. THERE IS SOME CONCERN CLOUD COVER WILL PERSIST THROUGH THE AFTN HOURS... LIMITING HEATING/INSTABILITY DEVELOPMENT. FORCING WILL BE AVAILABLE FROM A WEAK DRYLINE AND BROAD SCALE ASCENT... AS WELL AS ANY LEFT OVER BOUNDARIES FROM EARLIER CONVECTION. ALTHOUGH INSTABILITY WILL BE PRIMARY QUESTION THIS AFTN... THERE WILL BE QUITE A BIT OF SHEAR AVAILABLE... 40 TO 55KTS 0-6KM AND IF WE CAN RECOVER... A WINDOW AROUND 21-03Z FOR SOME 1000- 1400 J/KG SKINNY CAPE PROFILES. MUCH OF THE INSTABILITY WILL BE ELEVATED... AND GIVEN BUFR PROFILES... LARGE HAIL... UP TO GOLF BALLS... AND SEVERE WINDS WOULD BE THE PRIMARY HAZARDS... WITH THE TORNADO HAZARD LOW. FOR WEDNESDAY... CLUSTERS OR A COMPLEX OF THUNDERSTORMS WILL LIKELY BE ONGOING AND LIFTING EWRD ACROSS CENTRAL OK THROUGH SUNRISE. THIS ACTIVITY WILL SLOWLY DIMINISH AND EXIT EWRD THROUGH THE DAY AS THE H500 SHORT WAVE FINALLY EJECTS NWRD INTO THE NRN HIGH PLAINS. ONCE AGAIN... HOW THIS ACTIVITY EVOLVES THROUGH THE MORNING WILL PLAY THE LEAD ROLE IN OUR SEVERE WEATHER CHANCES WED AFTN/EVENING. AT THE MOMENT... IF WE CAN GET CLEARING ACROSS WRN OK IN THE VICINITY OF THE DRYLINE... MODEST MLCAPE VALUES CAN BE ANTICIPATED... 1000-1500 J/KG. THIS PAIRED WITH GOOD SHEAR ONCE AGAIN... STORMS ON THE DRYLINE WILL LIKELY DEVELOP RAPIDLY AND BE GOOD HAIL PRODUCERS... UP TO TENNIS BALL SIZED... AS WELL AS PRODUCING POTENTIALLY DAMAGING WIND GUSTS. AS FOR TORNADOES... CHANCES LOOK BETTER IN KS... WHERE SHEAR/LL WINDS WILL BE ENHANCED BY THE MORE FAVORABLE POSITION OF THE SFC LOW OVER ERN CO/WRN KS. GUIDANCE SUGGESTS OK AND NRN TX STORMS WILL MOVE OFF THE DRYLINE... BECOMING ELEVATED QUICKLY AFTER SUNSET. THE CHANCE FOR SEVERE STORMS WILL DIMINISH OVERNIGHT... WITH SCATTERED THUNDERSTORMS PERSISTING THROUGH THU MORNING. FOR THURSDAY INTO FRIDAY... PRECIPITATION CHANCES WILL CONTINUE... ESPECIALLY THU NIGHT INTO FRI... AS A DIFFUSE FRONTAL BOUNDARY STALLS/LINGERS NEAR THE OK/KS BORDER... EXTENDING FROM THE PANHANDLE INTO ERN KS. H500 FLOW REMAINS FAIRLY STATIC AS THE SRN PLAINS REMAINS SANDWICHED BETWEEN A DEEPENING TROUGH IN THE WEST AND A SHARP POSITIVE RIDGE INTO THE MID-ATLANTIC COAST. WITH THIS FLOW REGIME AND THE LINGERING WEAK FRONTAL BOUNDARY... COUPLED WITH CONTINUOUS MOISTURE ADVECTION FROM THE GULF... PERSISTENT AND POSSIBLY EXCESSIVE RAINFALL LIKELY... ESPECIALLY FRI INTO SAT AM. THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE WEEKEND AS THE H500 TROUGH FINALLY LIFTS E/NE ACROSS THE CENTRAL ROCKIES. WITH THIS... THE DRY LINE WILL MAKE ANOTHER PUSH ON SATURDAY... WITH STRONG TO SEVERE STORMS POSSIBLE ONCE AGAIN. DETAILS REMAIN HAZY GIVEN WHATS POSSIBLE TO TRANSPIRE BETWEEN NOW AN THEN. AS WITH TODAY AND WED... THUNDERSTORMS SAT WILL BE DEPENDENT ON HOW THE ATMOSPHERE RECOVERS FROM THE MORNING CONVECTION. PRECIP CHANCES WILL DIMINISH MON INTO TUES. JTK && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 77 63 78 65 / 40 70 40 50 HOBART OK 72 63 80 63 / 70 80 40 50 WICHITA FALLS TX 76 65 82 66 / 60 70 30 50 GAGE OK 69 60 82 62 / 70 80 20 20 PONCA CITY OK 79 65 78 66 / 10 80 50 40 DURANT OK 78 65 78 66 / 60 70 50 40 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
416 AM CDT TUE MAY 5 2015 .SHORT TERM /NOW THROUGH WEDNESDAY/...UPPER TROF ACROSS THE FOUR CORNERS REGION WILL OPEN UP AND WEAKEN AS IT HEADS NORTHEASTWARD INTO COLORADO THEN BECOME ABSORBED IN THE DEEPENING LARGER SCALE TROUGH ACROSS THE WESTERN CONUS. DIFFLUENCE REMAINS ACROSS THE AREA BUT BETTER DYNAMICS ASSOCIATED WITH THE UPPER TROF WILL REMAIN WELL REMOVED FROM THE AREA. 700MB FLOW STRENGTHENS AND REINFORCES MID LEVEL CAPPING WITH DRY AIR ADVECTING FROM THE MEXICAN PLATEAU AND OVER SPREADING THE AREA. LEFT SLIGHT CHANCE POPS THIS MORNING FOR FAR WESTERN SECTIONS BUT BELIEVE CAP WILL KEEP THE LID ON MOST IF NOT ALL PRECIPITATION TODAY. HRRR AND NAM12 SUPPORT THIS IDEA. BREEZY CONDITIONS CONTINUE TODAY WITH DEEPENING LOW PRESSURE ACROSS WEST TEXAS WITH GUSTS APPROACHING 30 MPH. THERE ARE INDICATIONS IN THE MODELS OF THUNDERSTORMS DEVELOPING ON THE HIGHER TERRAIN THIS EVENING AND MOVE EASTWARD TOWARDS OUR AREA BUT DRY AIR SHOULD WEAKEN THEM BEFORE MAKING ACROSS THE RIVER. THEREFORE WILL KEEP FORECAST DRY TONIGHT. BREEZY CONDITIONS CONTINUE WEDNESDAY WITH ANOTHER ROUND OF 700MB DRY AIR ADVECTING FROM THE WEST. CONDITIONS WILL BE FAIRLY SIMILIAR TO THE PAST SEVERAL DAYS. HIGHS IN THE 80S THE NEXT SEVERAL DAYS AND PERHAPS REACHING 90 DEGREES IN THE FAR NORTHWESTERN SECTIONS OF ZAPATA COUNTY. LOWS WILL BE IN THE 70S. .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...AS LOW PRESSURE TROUGHS DEEPEN ACROSS SW U.S. AND JUST OFF THE SE U.S. COAST MID TO UPPER LEVEL RIDGE BUILDS OVER SOUTH TEXAS AND THE WESTERN GULF. THIS SHOULD IN A MOSTLY DRY RAINFREE WED NIGHT THROUGH SUNDAY PERIOD. NOT UNTIL THE WESTERN TROUGH BEGINS TO MOVE NORTHEAST LATE NEXT WEEKEND INTO EARLY NEXT WEEK WILL THERE BE SOME INCREASE IN THE CHANCE OF RAIN. MODELS REMAIN RATHER PERSISTENT IN THIS PATTERN AND HAVE BEEN IN GOOD CONSISTENCY MAKING FOR A BETTER THAN AVERAGE CONFIDENCE IN THE OUTGOING FORECAST. OVERALL, THE EARLY DOG DAYS OF SUMMER WILL BE SETTING UP AS THE BUILDING UPPER RIDGE AND STRONG CAPPING INVERSION BETWEEN 850-700MB TO DOMINATE. THE BUILDING RIDGE PROMOTES A DIVERGENT Q VECTOR FIELD OR A CONFLUENT FLOW ALOFT AND THE 850-700MB CAPPING INVERSION STRENGTHENS WITH A THE PERSISTENT SOUTHWEST FLOW. WITHOUT ANY LIFTING MECHANISM AND DISTURBANCES/VORT MAXES LIKELY TO BE DIVERTED NORTHEAST OF THE AREA DO NOT SEE ANY SIGNIFICANT CHANCE OF RAIN. WITH THAT SAID HAVE KEPT THE LOW CHANCE POPS ACROSS THE NW ZONES JUST IN CASE A ROUGE THUNDERSTORM MOVES IN FROM THE SIERRA MADRE. WARM/HOT, HUMID AND BREEZY WILL BE THE WORD THROUGH AT LEAST SUNDAY WITH WINDIEST DAYS NEXT WEEKEND AS THE UPPER TROUGH OVER THE DESERT SW LIFTS INTO THE CENTRAL PLAINS STRENGTHENING THE PRESSURE GRADIENT. AS WE MOVE INTO NEXT WEEK MODELS SUGGEST AN INCREASE IN RAIN CHANCES. THE WEAKENING OF THE RIDGE AND A TRAILING COLD FRONT MOVING INTO CENTRAL TEXAS ALONG WITH POOLING MOISTURE SOUTH OF THE BOUNDARY LOOKS TO THE INGREDIENTS NEEDED TO GET A FEW STORMS IN OUR REGION. HAVE BROAD BRUSHED THE CWA WITH LOW GRADE POPS NEXT MONDAY AND TUESDAY TO ACCOMMODATE THE MODEL CONSENSUS. && .MARINE...NOW THROUGH WEDNESDAY...MODERATE SOUTHEAST WINDS AND MODERATE SEAS WILL CONTINUE AS HIGH PRES REMAINS DOMINANT OVER THE SOUTHEAST U.S. AND THE NORTH GULF...COUNTERBALANCED BY SOMEWHAT LOWER PRESSURE OVER THE SOUTHERN HIGH PLAINS. WINDS AND SEAS MAY INCREASE SLIGHTLY AT TIMES...WITH SMALL CRAFT EXERCISE CAUTION TO LOW END SMALL CRAFT ADVISORY CONDITIONS POSSIBLE. WEDNESDAY NIGHT THROUGH SUNDAY...A MODERATE TO STRONG PRESSURE GRADIENT TO PERSIST THIS PERIOD. BROAD HIGH PRESSURE OVER THE GULF TO INTERACT WITH LOWER PRESSURE OVER NW TEXAS TO PRODUCE MARGINAL SMALL CRAFT ADVISORY CONDITIONS WEDNESDAY NIGHT THROUGH FRIDAY. LOW PRESSURE STRENGTHEN OVER THE WEEKEND WITH A POSSIBLE UPTICK IN WINDS AND SEAS. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 85 75 83 75 / 10 10 10 10 BROWNSVILLE 86 74 85 75 / 10 10 10 10 HARLINGEN 87 74 87 74 / 10 10 10 10 MCALLEN 89 75 88 75 / 20 10 10 10 RIO GRANDE CITY 87 74 90 74 / 20 10 20 20 SOUTH PADRE ISLAND 81 75 83 75 / 10 10 10 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 55/59
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1141 PM CDT Mon May 4 2015 .AVIATION... /06Z TAFS/ Widespread convection continues across West Central TX and may be a factor at KABI during the overnight hours. At KABI, VCSH was included after 08z, with the remaining terminals dry. Low clouds are expected to develop once again areawide, and may encroach on IFR range (<1000 ft) during the early morning hours. The most likely area for IFR ceilings will be along the I-10 corridor. However, the abundant mid/high cloud cover and strong low-level jet may preclude ceilings below 1000 ft. MVFR ceilings will persist most of the day and scattered convection is anticipated by late morning across much of West Central TX. Thunderstorms are forecast for the afternoon and evening hours, but scattered coverage limits the probability at any given forecast terminal. Thus, -SHRA and VCSH were included as the prevailing weather group for now. Johnson && .PREV DISCUSSION... /ISSUED 836 PM CDT Mon May 4 2015/ UPDATE... Convection continues to the west of the CWA. One batch of storms is lifting slowly northeast across the South Plains from Lamesa to near Snyder. A few showers and thunderstorms extend to the south and southeast from this complex, generally along and north of the Colorado River. Farther south, a persistent, right-moving supercell continues to parallel I-10 near Ft. Stockton, with additional development to its west. Given the proximity of this storm to Crockett County, a Tornado Watch was issued through 2 AM. Surface based instability is a bit more limited east of the Pecos River, so the thinking is that this storm should weaken as it moves into Crockett County. However, the HRRR has shown a tendency for additional development in the Big Bend area overnight. There is also the potential for additional thunderstorms to move into the Big Country and Concho Valley late tonight and early Tuesday. If this occurs, it may limit the severe weather potential for tomorrow afternoon/evening. Will have to wait and see how this plays out. PREV DISCUSSION... /ISSUED 629 PM CDT MON MAY 4 2015/ AVIATION... /00Z TAFS/ Flight conditions will deteriorate at all terminals through the next 24 hours. Ceilings will drop into the 1500 to 2500 feet range after 04z at all TAF sites, with southern terminals dropping to around 800 feet after 08z. Southeast winds gusting over 20 knots are likely area- wide tonight, with these gusts increasing to near 30 knots tomorrow afternoon across the northern terminals, and near/over 20 knots farther south. Showers and thunderstorms may develop at any time during the TAF cycle. For now, have inserted VCTS at KABI and KSJT for the next couple of hours based on radar trends.. PREV DISCUSSION... /ISSUED 353 PM CDT Mon May 4 2015/ SHORT TERM... (Tonight-Tuesday Night) The main weather concerns for the short term will be the isolated threat of severe thunderstorms this afternoon and a little more widespread threat for severe weather Tuesday. Thunderstorms have already developed this afternoon across much of west central Texas. So far, storms have been of the single cell pulse variety and staying below severe levels. We may see an isolated storm or two produce severe hail this afternoon/evening. However, the bigger threat for severe weather today will be farther west over the Permian Basin. We may see a few storms cross into our western counties this evening...so have kept precipitation chances going overnight. For tomorrow...an upper trough over eastern New Mexico will head northeast across west Texas as the dryline heads east toward our area. Increased cloud cover may limit instability slightly. However, with decent shear across the area, expect more organized convection to develop tomorrow afternoon with a slightly higher threat for severe weather. Think the best chance for severe storms will be across the northern and western parts of the area. Storms should continue into the evening hours. LONG TERM... (Wednesday-Monday) Unsettled weather will continue through the majority of the extended period, with showers and thunderstorms possible through next weekend. The short-wave trough will lift northeast of the area on Wednesday, while another significant upper trough develops across the western states. We`ll remain in southwest flow aloft ahead of this system through Friday, with periodic disturbances moving across the area. The dryline will remain west of the area on Wednesday but will mix east into far western counties Thursday and Friday. Showers and thunderstorms are expected to develop just about anywhere on Wednesday due to a weaker CAP, with a few strong to severe storms possible during the late afternoon and evening hours. Scattered strong to severe thunderstorms will remain a possibility Thursday and Friday ahead of the upper trough to our west, with a continued chance for severe storms next weekend as the upper trough moves across the Plains. && .PRELIMINARY POINT TEMPS/POPS... Abilene 62 74 64 80 66 / 30 50 60 40 40 San Angelo 63 76 65 82 66 / 30 30 40 30 30 Junction 64 77 66 80 67 / 20 40 40 40 30 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 25
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
348 AM MDT TUE MAY 5 2015 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 WEBCAMS ALONG INTERSTATE 80 HAVE CONSISTENTLY SHOWN DENSE FOG FROM THE SUMMIT TO CHEYENNE OVER THE PAST FEW HOURS. DECIDED TO ADD CENTRAL LARAMIE COUNTY (CHEYENNE) TO THE DENSE FOG ADVISORY THRU 16Z WITH THE CYS OBS DROPPING TO ONE QUARTER MILE. THE LOW CLOUDS AND FOG WILL REMAIN QUITE PERSISTENT THROUGH THE MORNING WITH THE HRRR MODEL INDICATING LIFR/IFR CONDITIONS THROUGH 18Z FROM THE INTERSTATE 80 SUMMIT EASTWARD TO CHEYENNE COUNTY. THIS MAKES SENSE AS THE OVERALL SFC PATTERN OF VERY MOIST SOUTH TO SOUTHEAST WINDS WILL CONTINUE THROUGH THE MORNING. WATER VAPOR IMAGERY SHOWS THE SUBTROPICAL UPPER LOW SPINNING OVER NORTHEAST ARIZONA. THE MODELS MOVE THIS FEATURE TO THE NORTHEAST OVER THE COURSE OF THE DAY TO NEAR NORTHERN COLORADO BY THIS EVENING. ONLY AN ISOLATED TO SCATTERED COVERAGE OF SHOWERS IS EXPECTED THROUGH THE EARLY AFTN ALONG THE COLORADO BORDER. HOWEVER...MIDLVL HEIGHT FALLS WILL COMBINE WITH INCREASING DEEP LAYER MOISTURE TO PROMOTE A MORE WIDESPREAD COVERAGE BY THE LATE AFTN AND EARLY EVENING. MOISTURE IS PLENTIFUL WITH THIS SYSTEM...IN FACT PW VALUES OF 0.75-1.0 INCHES OVER THE PLAINS ARE 2 STANDARD DEVIATIONS ABOVE NORMAL FOR EARLY MAY. THUS...WITH RELATIVELY SLOW STORM MOTIONS...LOCALLY HEAVY RAIN WILL BE A CONCERN ESPECIALLY OVER THE NEBRASKA PANHANDLE. WHILE ISOLATED TSTMS WILL BE POSSIBLE THIS AFTN...THE VERY WEAK INSTABILITY AND SHEAR WILL MAKE STRONG STORMS UNLIKELY. SPC HAS DROPPED THE MARGINAL THREAT OVER THE SOUTHERN PANHANDLE. WITH THE MIDLVL DISTURBANCE OVERHEAD TONIGHT...WILL KEEP A CHANCE OF SHOWERS GOING. SOUTHEAST SFC WINDS ARE IN PLACE THRU 12Z WED...SO FOG WILL AGAIN BE A THREAT OVER PORTIONS OF THE AREA. THE SHORTWAVE WILL PUSH INTO WESTERN SOUTH DAKOTA/NEBRASKA BY WED AFTN. THE MODELS SHOW THE HIGHEST QPF OVER THE PLAINS OF SOUTHEAST WY AS A SFC COLD FRONT INTERACTS WITH GOOD MOISTURE. WILL HAVE ISOLATED TSTMS DURING THE AFTN WITH SOME LIMITED CAPE. PRECIP CHANCES DROP OFF WED EVENING BEHIND THE FRONT AS A DRIER AIRMASS MOVES IN. THERE COULD ACTUALLY BE A 18-24 HR PERIOD FROM WED EVENING THRU THURS AFTN WHEN MUCH OF THE CWA WILL BE PRECIP FREE. SCATTERED STORMS WILL ONCE AGAIN DEVELOP ALONG AND WEST OF THE LARAMIE RANGE BY THURS AFTN...WITH LIMITED COVERAGE OVER THE PLAINS IN A MORE STABLE AIRMASS. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 UNSETTLED WEATHER CONTINUES IN THE LONG TERM. MEDIUM RANGE GUIDANCE CONTINUES TO ADVERTISE THE POSSIBILITY OF WINTER WEATHER RETURNING TO THE AREA LATE IN THE WEEKEND. STARTING OFF THURSDAY NIGHT...WE STILL HAVE THE STALLED SURFACE BOUNDARY LAYING ALONG THE LARAMIE RANGE...OR SLIGHTLY WEST. BOTH THE GFS AND ECMWF VERY SIMILAR BRINGING ANOTHER PIECE OF ENERGY NORTHEAST FROM THE DESERT SOUTHWEST TO INTERACT WITH THIS BOUNDARY...SO WILL KEEP CHANCE POPS GOING FOR THE THURSDAY NIGHT TIME FRAME. PROBABLY PRETTY LIGHT SHOWERS THOUGH AS HAS BEEN THE CASE THE PAST FEW NIGHTS. CONVECTION PICKS UP THROUGH FRIDAY AFTERNOON WITH BOTH MODELS CONCENTRATING ON THE SOUTHERN PANHANDLE AND NORTHEASTERN COLORADO. SOUTHEAST UPSLOPING WINDS TO CONTINUE. GFS AND ECMWF CONTINUE TO AGREE ON A CLOSED LOW ROUNDING THE BASE OF THE LONGWAVE TROUGH SATURDAY MORNING AND BEGINNING TO LIFT NORTHEAST INTO SOUTHWESTERN COLORADO SATURDAY AFTERNOON. OUR FORECAST AREA IS SQUARE IN THE WRAP AROUND MOISTURE TO THE NORTH OF THIS LOW. ECMWF A LITTLE FASTER ON MOVEMENT OVER THE GFS...MOVING THE LOW INTO CENTRAL NEBRASKA ROUGHLY 12 HOURS FASTER THAN THE GFS. BOTH ARE COLD THOUGH ON 700MB TEMPERATURES AND COLD ENOUGH FOR WIDESPREAD SNOW. BOTH ARE SHOWING 850MB WINDS OF 40 TO 45KTS ACROSS THE PANHANDLE AND EASTERN WYOMING. WINTER IS NOT DONE WITH SOUTHEAST WYOMING AND WE NEED TO BE WATCHING THE EVOLUTION OF THIS EVENT AS HEAVY SNOW AND WINTER HEADLINES ARE DEFINITELY A POSSIBILITY FOR PORTIONS OF THE FORECAST AREA...POSSIBLY EVEN THE PANHANDLE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1055 PM MDT MON MAY 4 2015 WIDESPREAD IFR/LIFR FOR THE OVERNIGHT HOURS FOR MOST SOUTHEAST WYOMING AND NEBRASKA PANHANDLE AIRPORTS WITH SOUTHEAST TO EAST UPSLOPING WINDS. EXPECT THIS TO LAST THROUGH THE MID TO LATE MORNING HOURS BEFORE CONDITIONS IMPROVE SOME...BUT THEN WE WILL BE DEALING WITH SHOWERS AND THUNDERSTORMS. LOW STRATUS RETURNING TUESDAY EVENING...BECOMING WIDESPREAD ONCE AGAIN. && .FIRE WEATHER... ISSUED AT 345 AM MDT TUE MAY 5 2015 A COOL AND WET WEATHER PATTERN WILL KEEP FIRE WEATHER CONCERNS VERY LOW THROUGH THE WEEKEND. AFTERNOON AND EVENING SHOWERS WILL BE POSSIBLE TODAY THROUGH THURSDAY...WITH GOOD CHANCES FOR MEASURABLE RAIN. MORE SUBSTANTIAL PRECIPITATION AMOUNTS ARE LOOKING POSSIBLE BY LATE FRIDAY INTO SUNDAY ASSOCIATED WITH A STRONG STORM SYSTEM. MINIMUM RELATIVE HUMIDITY VALUES SHOULD BE WELL ABOVE CRITICAL THRESHOLDS THROUGH THE PERIOD. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...DENSE FOG ADVISORY UNTIL 10 AM MDT THIS MORNING FOR WYZ116>118. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...GCC AVIATION...GCC FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS TUCSON AZ
853 AM MST TUE MAY 5 2015 .SYNOPSIS...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY NORTHEAST OF TUCSON INTO THIS EVENING. DRY CONDITIONS WILL THEN PREVAIL WEDNESDAY INTO EARLY NEXT WEEK. THE EXCEPTION WILL BE A FEW SHOWERS AND THUNDERSTORMS ACROSS THE WHITE MOUNTAINS SATURDAY. EXPECT BREEZY TO WINDY CONDITIONS DURING THE LATTER PART OF THE WEEK. BELOW NORMAL DAYTIME TEMPERATURES WILL OCCUR INTO SATURDAY FOLLOWED BY A SIGNIFICANT WARMING TREND EARLY NEXT WEEK. && .DISCUSSION...THE UPPER LOW THAT BROUGHT SHOWERS AND THUNDERSTORMS TO THE AREA YESTERDAY AND LAST NIGHT WILL CONTINUE TO INFLUENCE THE WEATHER TODAY. RESIDUAL MOISTURE COMBINED WITH DAYTIME HEATING AND SOME SUPPORT FROM THE UPPER LOW WILL RESULT IN MORE SHOWERS AND THUNDERSTORMS TODAY. LATEST HRRR MODEL SOLUTION KEEPS MOST OF THIS ACTIVITY JUST EAST AND NORTHEAST OF THE TUCSON METRO THIS AFTERNOON AND EVENING. THEREAFTER...MODELS EJECT THIS UPPER LOW NORTHEAST INTO THE CENTRAL PLAINS BY TOMORROW MORNING RESULTING IN A BREAK IN RAIN CHANCES. HOWEVER...ANOTHER SYSTEM WAS PROGGED TO DROP SOUTH ALONG THE INTERIOR WEST COAST INTO CENTRAL CALIFORNIA ON THURSDAY. THIS NEXT SYSTEM WILL BRING STRONG AND GUSTY WINDS TO THE AREA AS EARLY AS TOMORROW BUT MORE SO THURSDAY. CURRENT FORECAST LOOKED ON TRACK...SO NO UPDATES NECESSARY THIS MORNING. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR MORE DETAILS. && .AVIATION...VALID THRU 06/18Z. SCATTERED -TSRA/-SHRA WILL PREVAIL TODAY MAINLY ACROSS THE WHITE MOUNTAINS NE OF KSAD. EXPECT ISOLATED -TSRA/-SHRA FURTHER SWWD TO NEAR THE CATALINA/RINCON MOUNTAINS NEAR KTUS. DRY CONDITIONS WILL THEN PREVAIL LATE TONIGHT AND EARLY WEDNESDAY MORNING. OTHERWISE... IMPROVING CONDITIONS THIS PERIOD AS A LOW PRESSURE TROUGH OVER ARIZONA THIS MORNING MOVES INTO NEW MEXICO THIS EVENING. CLOUDS WILL DECREASE FROM WEST TO EAST THIS AFTERNOON WITH CLEAR SKIES OR MOSTLY CLEAR SKIES EARLY WEDNESDAY MORNING. SURFACE WIND THIS AFTERNOON WILL BE WLY/NWLY 12-18 KTS WITH GUSTS OF 20-25 KTS. SURFACE WIND WILL BE MAINLY LESS THAN 10 KTS AT OTHER TIMES. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A CHANCE OF SHOWERS AND THUNDERSTORMS CONTINUES MAINLY EAST OF TUCSON TODAY...AND A FEW SHOWERS MAY LINGER ACROSS THE WHITE MOUNTAINS THIS EVENING. DRY CONDITIONS WILL THEN PREVAIL LATE TONIGHT. A LOW PRESSURE SYSTEM WILL STRENGTHEN NORTHWEST OF THE AREA WEDNESDAY INTO FRIDAY. THIS SYSTEM WILL PRODUCE BREEZY CONDITIONS WEDNESDAY AFTERNOON FOLLOWED BY BREEZY TO WINDY CONDITIONS THURSDAY AND FRIDAY. HOWEVER...DAYTIME MINIMUM RELATIVE HUMIDITIES AND FUEL MOISTURE WILL BE MARGINAL AT BEST TO PRODUCE CRITICAL FIRE CONDITIONS. A FEW SHOWERS AND THUNDERSTORMS MAY THEN OCCUR ACROSS THE WHITE MOUNTAINS SATURDAY AS THE LOW PRESSURE SYSTEM MOVES NORTH OF THE AREA. EXPECT LESS WIND THIS WEEKEND ALTHOUGH SOME AFTERNOON GUSTINESS WILL OCCUR DUE TO DAYTIME HEATING. && .PREV DISCUSSION...UPPER LEVEL TROUGH WAS OVER THE WRN CONUS THIS MORNING WITH A WEAK LOW PRESSURE SYSTEM CENTERED OVER NERN ARIZONA. THIS LOW PRESSURE SYSTEM WILL FILL AND MOVE EWD INTO THE CENTRAL ROCKIES THIS AFTERNOON. THE NEXT UPSTREAM COLD UPPER LOW WILL DIG OVER SRN BRITISH COLUMBIA AND THE PACIFIC NW. MEANWHILE...ADEQUATE MOISTURE WILL PROVIDE A CHANCE OF SHOWERS/TSTMS THIS MORNING ACROSS THE WHITE MOUNTAINS...AND A SLIGHT CHANCE OF SHOWERS/TSTMS WILL OCCUR FURTHER SWWD TO NEAR THE TUCSON METRO AREA. DRIER AIR WILL THEN SPREAD EWD ACROSS THE AREA THIS AFTERNOON INTO TONIGHT. A CHANCE OF SHOWERS/TSTMS CONTINUES THIS AFTERNOON ACROSS THE WHITE MOUNTAINS WITH ISOLATED SHOWERS/TSTMS ACROSS GRAHAM COUNTY. ANY SHOWERS/TSTMS THIS EVENING SHOULD BE CONFINED TO THE WHITE MOUNTAINS. DRY CONDITIONS WILL THEN PREVAIL LATE TONIGHT. THE FLOW ALOFT WILL BECOME INCREASINGLY SWLY WED AS THE COLD UPPER LOW PRESENTLY OVER SRN BRITISH COLUMBIA AND THE PACIFIC NW DIGS INTO THE GREAT BASIN. A TIGHTENING MID-LEVEL GRADIENT AHEAD OF THIS SYSTEM WILL PRODUCE SOME BREEZINESS WED AFTERNOON. EXPECT BREEZY TO WINDY CONDITIONS THUR-FRI AS THE LOW PRESSURE SYSTEM CONTINUES TO DEEPEN NW OF THE AREA. HAVE INTRODUCED A SLIGHT CHANCE OF SHOWERS/ TSTMS ACROSS THE WHITE MOUNTAINS SAT AS THE UPPER LOW FILLS AND MOVES NORTH OF THE AREA. OTHERWISE...DRY CONDITIONS WILL PREVAIL SAT- MON. EXPECT LESS WIND THIS WEEKEND...ALTHOUGH SOME AFTERNOON GUSTS WILL OCCUR DUE TO DAYTIME HEATING. BELOW NORMAL DAYTIME TEMPS WILL OCCUR THRU SATURDAY FOLLOWED BY A WARMING TREND SUN-MON. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1042 AM EDT TUE MAY 5 2015 .SYNOPSIS... A WEAK COLD FRONT MAY BRING A FEW BRIEF SHOWERS TODAY...BUT DRY WEATHER AND MILD TEMPERATURES WILL DOMINATE. LITTLE CHANGE IS EXPECTED THROUGH THE WEEKEND...WITH MILD TO WARM AFTERNOON/S AND MAINLY DRY WEATHER PERSIST. A SLOW MOVING FRONT MAY BRING A FEW SHOWERS LATE THIS WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1041 AM UPDATE... WEAK COLD FRONT STILL CROSSING THE REGION. THIS FRONT EXTENDED FROM JUST EAST OF KLWM...TO NEAR KORH...TO JUST SOUTH OF KBDL. 05/12Z CHH SOUNDING SHOWED AN IMPRESSIVE SURFACE-BASED INVERSION. KBOX 88D SHOWING THE MAJORITY OF THE SHOWERS MOVING OVER THE COASTAL WATERS EAST OF MA MID-MORNING. LATEST RUNS OF THE HRRR AND RAP PREDICTING MORE SHOWERS DEVELOPING FARTHER WEST LATE THIS MORNING...THEN MOVING ACROSS PORTIONS OF RI AND SOUTHEAST MA. THIS IS ALSO STARTING TO SHOW IN THE RADAR DATA...SO RELIED HEAVILY ON A HRRR/RAP COMBINATION TO UPDATE RAINFALL CHANCES THROUGH THE REST OF TODAY. TEMPERATURES WILL BE TRICKY. LOTS OF CLOUD COVER THIS MORNING. VISIBLE SATELLITE DATA SHOWING PLENTY OF CLEARING THOUGH BEHIND THE COLD FRONT...AT LEAST FOR NOW. OPEN-CELLULAR STRATOCUMULUS CLOUDS STARTING TO POP ACROSS SOUTHERN VT AND SOUTHERN NH. FULLY EXPECT THIS TREND TO CONTINUE ACROSS SOUTHERN NEW ENGLAND LATER TODAY...ONCE THIS COLD FRONT MOVES COMPLETELY OFFSHORE. KEPT TEMPERATURES WELL ABOVE NORMAL...BUT NOT QUITE AS HIGH AS YESTERDAY. PREVIOUS DISCUSSION... PLENTY OF MID LEVEL CLOUDINESS WILL BE AROUND DURING THE MORNING... BUT STILL EXPECT PEEKS OF SUN. AS THE AFTERNOON WEARS ON...EXPECT SUNSHINE TO BECOME MORE PREVALENT AS DRIER AIR WORKS IN BEHIND THE COLD FRONT. GIVEN VERY MILD START...HIGH TEMPS IN MOST LOCALES SHOULD CLIMB WELL UP INTO THE 70S. IT/S NOT OUT OF THE QUESTION THAT A SPOT LOCATION OR TWO HITS 80. HOWEVER...ACROSS THE IMMEDIATE COAST WEAKENING PRESSURE GRADIENT BEHIND THE COLD FRONT WILL ALLOW COOLING SEA BREEZES TO DEVELOP. IN THESE LOCATIONS...MILD LATE MORNING TEMPS WILL PROBABLY FALL BACK INTO THE UPPER 50S AND LOWER 60S...INCLUDING BOSTON. JUST INLAND FROM THE COAST THOUGH IT WILL REMAIN QUITE MILD EVEN BEHIND THE FRONT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT AND WEDNESDAY... DRY AND PLEASANT WEATHER EXPECTED FOR MOST OF TONIGHT AS HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT. LOW TEMPS WILL MAINLY BE IN THE 40S...TO LOWER 50S. A MOISTURE STARVED SHORTWAVE WILL DROP DOWN IN WEST TO NORTHWEST FLOW ALOFT WED MORNING. NOT SURE IF IT WILL TRACK FAR ENOUGH NORTHWEST TO RESULT IN A BRIEF PERIOD OF SCATTERED SHOWERS ACROSS ANY PORTION OF OUR REGION. BEST SHOT IS NORTHERN CT...AND PERHAPS EVEN INTO PART OF RHODE ISLAND AND SOUTHEAST MA FOR A SHORT TIME. REGARDLESS...EVEN IF A FEW SHOWERS OCCUR THEY WILL BE SHORT-LIVED AND NOT AMOUNT TO MUCH. MORE IN THE WAY OF SUNSHINE SHOULD DEVELOP FROM NORTH TO SOUTH THROUGH WED AFTERNOON. HIGHS SHOULD GENERALLY REACH WELL INTO THE 70S IN MOST LOCATIONS...WITH THE WARMEST READINGS NORTH OF THE PIKE WHERE THE MOST SUNSHINE IS EXPECTED. ITS ALSO POSSIBLE THAT AREAS NEAR THE SOUTH COAST DO NOT REACH 70 ON WEDNESDAY...IF CLOUDS HANG ON LONGER THEN EXPECTED. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * SPRING TO SUMMER-LIKE TEMPERATURES THROUGH EARLY NEXT WEEK * HIGH PRESSURE WILL KEEP MAINLY DRY CONDITIONS INTO THIS WEEKEND * A SLOW MOVING FRONT MAY BRING SCATTERED SHOWERS SUN INTO MON OVERVIEW AND MODEL PREFERENCES... 00Z GEFS/12Z ECENS REMAIN IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL STEERING FLOW IN KEEPING AMPLIFIED PATTERN ACROSS THE LOWER 48 THROUGH MOST OF THIS FORECAST PERIOD. NOTING LONG WAVE TROUGHING WITH A FEW CUTOFF SHORT WAVES DIVE S INTO THE BASE OF THE TROUGH INTO THIS WEEKEND WHILE LONG WAVE RIDGE SLOWLY BUILDS E AS IT NOSES N THROUGH EASTERN QUEBEC TO LABRADOR. ALSO NOTING NEARLY STATIONARY CUTOFF LOW OFF THE SE U.S. COAST WITH SURFACE LOW/POSSIBLE SUBTROPICAL SYSTEM LATE IN THE WEEK OR THIS WEEKEND. WHILE THIS SYSTEM WILL NOT DIRECTLY AFFECT THE REGION... IT COULD CAUSE THE RIDGE TO HOLD IN PLACE AND SLOW AN APPROACHING COLD FRONT FOR LATE THIS WEEKEND INTO NEXT MONDAY. 00Z MODEL SUITE ALSO IN FAIRLY GOOD AGREEMENT INTO THIS WEEKEND... THEN THE GFS LOOKS TO BREAK DOWN RIDGING FASTER THAN GGEM/ECMWF... MAINLY DUE TO SHORT WAVE TRYING TO WORK OUT OF CENTRAL CANADA WHICH FLATTENS OUT THE RIDGE. WITH OVERALL BLOCKING PATTERN IN PLACE ACROSS NORTH AMERICA AND FURTHER E ACROSS THE ATLC...FEEL THIS WILL BE SLOW TO BREAK DOWN SO THINK THE SLOWER GUIDANCE IS THE WAY TO GO FOR SUN-MON. HOWEVER...WITH THE WIDE MODEL SOLUTIONS...HAVE LOW CONFIDENCE FROM SATURDAY INTO EARLY NEXT WEEK. LEANED TOWARD A BLEND OF MODEL GUIDANCE INTO THIS WEEKEND...THEN BLENDED TOWARD THE ENSEMBLES FOR SUN-MON WHICH WAS CLOSE TO THE HPC GUIDANCE. THIS YIELDED GOOD CONTINUITY TO THE PREVIOUS FORECAST. DETAILS... WEDNESDAY NIGHT...EXPECT STALLED FRONT NEAR THE S COAST TO TEND TO WASH OUT AS IT SHIFTS A BIT FURTHER S AS HIGH PRES AT THE SURFACE AND ALOFT SLOWLY PUSHES ACROSS THE REGION. WILL SEE GENERALLY DRY CONDITIONS WITH LIGHT/VRBL WINDS. THURSDAY-FRIDAY...RIDGING BUILDS E ACROSS NEW ENGLAND INTO EASTERN CANADA DURING THIS TIMEFRAME. EXPECT LIGHT/VRBL WINDS EARLY THU TO BECOME S-SW. THIS WILL KEEP MILD TEMPS IN PLACE EXCEPT ALONG THE S COAST WHERE THEY WILL BE TEMPERED WITH THE GENERAL ONSHORE WIND FLOW. MAY ALSO SEE BRIEF SEA BREEZES ALONG THE E COAST MAINLY ON FRIDAY. ALSO...DUE TO SEA SURFACE TEMPS RUNNING IN THE MID-UPPER 40S AND MILD TEMPS DURING THE NIGHTTIME HOURS...MAY SEE OVERNIGHT PATCHY FOG DEVELOP MAINLY ALONG THE COAST WHILE INCREASING DEWPTS MAY ALSO MEAN BRIEF PATCHY FOG ACROSS THE NORMALLY SUSCEPTIBLE INLAND LOCATIONS EACH NIGHT. HIGHS BOTH DAYS AWAY FROM THE S COAST WILL BE IN THE 70S... POSSIBLY UP TO AROUND 80 ACROSS PORTIONS OF THE CT VALLEY BOTH DAYS. SATURDAY THROUGH MONDAY...AS MENTIONED ABOVE...MODEL SOLUTIONS WIDEN. HAVE MENTIONED ONLY SLIGHT CHANCE POPS MAINLY N OF THE MASS PIKE SAT AFTERNOON/NIGHT. INCREASED POPS TO ONLY LOW CHANCE FOR SUN/MON FOR MOST AREAS...BUT WILL DEPEND UPON TIMING OF THE APPROACHING FRONT. EXPECT MILD TEMPS TO REMAIN IN PLACE THROUGH THIS WEEKEND WITH HIGHS IN THE 70S /EXCEPT COOLER ALONG IMMEDIATE S COAST/. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH WEDNESDAY/... TODAY...HIGH CONFIDENCE. EXPECT VFR CONDITIONS...THOUGH CIGS WILL LOWER TO 4-5KFT ALONG FRONT INVOF BAND OF SHOWERS AS IT MOVES S OUT OF CENTRAL MA THROUGH MIDDAY. MAY SEE BRIEF LOCAL MVFR CONDITIONS IN ANY HEAVIER SHOWERS. TONIGHT AND WEDNESDAY...HIGH CONFIDENCE. MAINLY VFR CONDITIONS. A BRIEF PERIOD OF ISOLATED TO SCATTERED SHOWERS MAY AFFECT NORTHERN CT AND POSSIBLY A PART OF RI/SOUTHEAST MA FOR A TIME WED AM. THIS MAY RESULT IN VERY BRIEF LOCALIZED MVFR CONDITIONS IF ANY OCCUR. KBOS TAF...HIGH CONFIDENCE IN TAF. SEA BREEZES EXPECTED TO DEVELOP THIS AFTERNOON AS A RESULT OF A WEAKENING PRESSURE GRADIENT BEHIND A COLD FRONT. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... HIGH CONFIDENCE THROUGH THE PERIOD. VFR AND DRY CONDITIONS. LOW RISK FOR PATCHY FOG EACH NIGHT FROM AROUND MIDNIGHT THROUGH SUNRISE WITH LOCAL MVFR-IFR CIGS/VSBYS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH WEDNESDAY/... TODAY THROUGH WEDNESDAY...HIGH CONFIDENCE. MARGINAL SMALL CRAFT SEAS WILL CONTINUE TO DIMINISH ACROSS THE OUTER COASTAL WATERS INTO THIS AFTERNOON. WINDS/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH WEDNESDAY UNDER A WEAK RIDGE OF HIGH PRESSURE. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...HIGH CONFIDENCE THROUGH THE PERIOD. WEDNESDAY NIGHT...LIGHT/VRBL WINDS BECOME S-SW AROUND OR AFTER MIDNIGHT AT 15 KT OR LESS. SEAS 3 FT OR LESS. THURSDAY...W-SW WINDS UP TO 15 KT ACROSS THE OPEN WATERS DURING THE AFTERNOON. SEAS REMAIN BELOW 5 FT. THURSDAY NIGHT THROUGH SATURDAY...SW WINDS 15 KT OR LESS WITH SEAS 2-4 FT. LOW CHANCE OF 5 FT SEAS ON THE EASTERN OUTER WATERS SAT AFTERNOON/NIGHT. && .FIRE WEATHER... MAINLY DRY WEATHER WITH LITTLE APPRECIABLE RAINFALL WILL CONTINUE THROUGH AT LEAST SATURDAY IF NOT INTO SUNDAY/MONDAY. WHILE WINDS FOR THE REST OF THE WORK WEEK WILL PROBABLY NOT BE STRONG ENOUGH FOR FIRE WEATHER HEADLINES...WE MAY HAVE TO BE MORE CONCERNED BY SATURDAY. THERE WILL BE AT LEAST A BIT MORE POTENTIAL FOR SOME MARGINAL FIRE WEATHER HEADLINE WIND GUSTS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANK/EVT NEAR TERM...BELK/FRANK/EVT SHORT TERM...FRANK LONG TERM...EVT AVIATION...BELK/FRANK/EVT MARINE...BELK/FRANK/EVT FIRE WEATHER...STAFF
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT TUE MAY 5 2015 .UPDATE... ISSUED AT 1045 AM CDT TUE MAY 5 2015 15Z/10AM SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY EXTENDING FROM NORTH-CENTRAL ILLINOIS INTO CENTRAL IOWA...GENERALLY ALONG A KANKAKEE...TO PEORIA...TO DES MOINES LINE. WIDESPREAD RAIN CONTINUES TO FALL NORTH OF THE FRONT: HOWEVER, MOSTLY SUNNY AND DRY CONDITIONS PREVAIL TO THE SOUTH ACROSS CENTRAL ILLINOIS. TEMPERATURES HAVE ALREADY RISEN WELL INTO THE 70S ACROSS ALL BUT THE FAR NORTHERN KILX CWA. BASED ON THE 12Z UPPER AIR SOUNDING AND ASSUMING MIXING UP TO ABOUT 750MB SIMILAR TO YESTERDAY AFTERNOON...HIGHS TODAY SHOULD REACH THE LOWER TO MIDDLE 80S. HAVE ADJUSTED TEMPS UP BY A FEW DEGREES ACCORDINGLY. && .SHORT TERM...(TODAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 A FRONTAL BOUNDARY IS ORIENTED WEST-EAST ACROSS CENTRAL IL THIS MORNING WITH PRECIPITATION IN ISENTROPIC ASCENT REGION LARGELY TO THE NORTH OF THE BOUNDARY. MODELS INDICATE THE BOUNDARY AND PRECIPITATION WILL SHIFT SLOWLY NORTHWARD TODAY. WEAK DISTURBANCES MOVING ALONG THE BOUNDARY WILL PRODUCE SOME ENHANCEMENTS IN CONVECTIVE SHOWER COVERAGE IN THE VICINITY...EARLY THIS MORNING FROM AROUND THE ILLINOIS RIVER NORTHWESTWARD...AND LATE IN THE AFTERNOON NORTH OF THE I-74 CORRIDOR. FOR THE MOST PART...CONVECTION SHOULD BE WEAK AT THIS POINT WITH ONLY WEAK MID-LEVEL INSTABILITY REMAINING THROUGH THE NIGHT...AND 0-6KM BULK SHEAR UP TO 25-30 KTS THIS MORNING DIMINISHING SUBSTANTIALLY FOR THE AFTERNOON. 1000-1500 JOULES OF SURFACE-BASED CAPE SHOULD BE ABLE TO DEVELOP WITH AFTERNOON HEATING ALONG/NORTH OF I-72 AND CAN`T RULE OUT ISOLATED THUNDERSTORMS SOUTHWARD TO I-72 AS A RESULT. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 ONGOING CONVECTION ALONG THE BOUNDARY OVER NORTHERN ILLINOIS THIS MORNING NOT ONLY DRIVING THE WEATHER THROUGHOUT THE DAY, BUT INTO THE OVERNIGHT AS WELL. GFS AND NAM CONTINUE TO KEEP A BIT OF PRECIP PRETTY FAR SOUTH, AS FAR SOUTH AS A LINE FROM HAVANA TO BLOOMINGTON. HOWEVER, THE RAP/RUC AND THE HRRR ARE PUSHING THE AREA OF CONVECTION WELL TO THE NORTH THROUGH THE MORNING WITH THE BOUNDARY. WHEN THE SECONDARY WAVE RIPPLES THROUGH THE REGION AFTER 00Z, IT WOULD BE DISPLACED NORTH OF THE FA. THE 4KM WRF HAS JUST THAT SOLUTION, STARTING MORE IN LINE WITH THE RAP/RUC AND HRRR...AND KEEPING THE FA DRY AFTER 00Z, BUT A LITTLE MORE GENEROUS WITH SOME ISOLATED INSTABILITY SHOWERS. HAVE KEPT ISO TS IN THE NORTH, MAINLY ALONG AND NORTH OF I-74 FOR THE EARLY EVENING. HIGH PRESSURE BEGINS TO BUILD BACK INTO THE REGION LATER TONIGHT, SOUTHERLY WINDS PUSHING THE FRONT BACK TO THE NORTH AND OUT OF THE FORECAST AREA THROUGH WED NIGHT. FORECAST REMAINS ROUGHLY THE SAME BEYOND DAY 3... PRECIP CHANCES SLOWLY EDGING BACK INTO WEST CENTRAL ILLINOIS FOR THURSDAY AS AN UPPER LEVEL WAVE PUSHES OUT OF THE SW. THE ENERGY IS PART OF A GENERAL PATTERN SHIFT TO MORE SOUTHWESTERLY FLOW WITH THE UPPER LEVEL TROF DIGGING BACK IN OVER THE SWRN CONUS. THE SFC LOW MOVES OUT INTO THE UPPER MIDWEST AND INTO CANADA BY THE END OF THE WEEK, BUT IN SHIFTING TO MORE SOUTHWESTERLY FLOW ALOFT, OPENS THE DOOR TO A SERIES OF SHORTWAVES THAT KEEP THE FORECAST WET FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND. TEMPS RATHER WARM THROUGH THE FORECAST WITH OVERCAST AND RAINY SKIES KEEPING THE OVERNIGHT LOWS UP A BIT, BUT LIKELY NOT NEARLY AS WARM AS THE TREND IN THE GUIDANCE. HAVE KNOCKED THEM DOWN A COUPLE DEGREES. SOUTHERLY FLOW AND A RELATIVELY WARM AIRMASS KEEPING THE HIGHS A BIT ABOVE NORMS, EVEN WITH THE PASSAGE OF THE FIRST LOW SKIRTING TO THE NW...THE MID LEVELS REMAIN WARM UNTIL THE MAIN TROF OVER THE SW LIFTS INTO AND OUT OF THE GREAT LAKES. COOLER AIR IN THE MIDLEVELS IS ONLY AROUND FOR 36 HOURS DAY 7/8 BEFORE THE WARM AIRMASS REESTABLISHES ITSELF. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 647 AM CDT TUE MAY 5 2015 SHOWERS HAVE MOVED OUT OF CENTRAL IL TAF SITES THIS MORNING WITH VFR CONDITIONS AT MOST SITES...AREAS BKN060-080 CIGS...AND IFR- LIFR CONDITIONS IN FOG AT SITES FROM KPIA-KC75 NORTHWESTWARD. FOG WILL DISSIPATE WITH DAYTIME HEATING IN A FEW HOURS. ALSO WITH DAYTIME HEATING...EXPECTING ISOLD TSRA DEVELOPING FROM AROUND 18Z-24Z. SCT-BKN CLOUD COVER SHOULD DEVELOP AS WELL GENERALLY ABOVE MVFR THRESHOLDS. PROBABILITY OF DEVELOPMENT AND TIMING UNCERTAINTY PREVENT EXPLICIT MENTION OF TSRA IN CENTRAL IL TAFS...HOWEVER MVFR OR WORSE CIGS/VSBYS POSSIBLE IN ISOLATED STORMS. INSTABILITY DECREASING OVERNIGHT SHOULD BRING AN END TO ANY STORMS SHORTLY AFTER SUNSET. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...ONTON LONG TERM...HJS AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1040 AM CDT TUE MAY 5 2015 .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * EAST-NORTHEAST WINDS INCREASING BACK TO 10 KT THIS AFTERNOON. * IFR CIGS POSSIBLY LIFTING TO MVFR THIS AFTERNOON...RETURNING TO LIFR TONIGHT. * SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN...MAINLY ALONG AND MORE LIKELY SOUTH OF MDW. KMD //DISCUSSION...UPDATED 12Z... THE RAIN IS SLOWLY SHIFTING NORTHEAST AND WILL CLEAR THE REGION THIS MORNING. NO ADDITIONAL LIGHTNING STRIKES ARE ANTICIPATED WITH THESE SHOWERS. THERE ARE SCATTERED REPORTS OF MVFR CIGS AND THE CIGS SHOULD LIFT TO VFR BEHIND THE SHOWERS. A STATIONARY FRONT WILL REMAIN SOUTH OF THE TERMINALS TODAY AND COULD SEE SHOWERS AND PERHAPS A THUNDERSTORM FIRE ALONG THE FRONT THIS AFTERNOON. THE SHOWERS AND STORMS COULD IMPACT THE EASTERN TERMINALS...BUT DUE TO LOW CONFIDENCE ONLY HAVE A VCSH. THINKING RFD WILL NOT BE IMPACTED. EAST WINDS AT 10 KT DIMINISH TO BELOW 10 KT THIS EVENING AND THEN BEGIN TO BACK TO SOUTHEAST TOMORROW AS THE FRONT LIFTS NORTH. JEE //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM-HIGH THAT EAST-NORTHEAST WINDS PICK BACK UP TO AROUND 10 KT THIS AFTERNOON. * MEDIUM-HIGH CONFIDENCE IN ORD REMAINING DRY THE REST OF THE DAY. MEDIUM THAT AFTERNOON SHOWERS/ISOLATED T-STORMS REMAIN SOUTH OF MDW. * MEDIUM CONFIDENCE IN IFR CIGS LIFTING TO MVFR BUT LOW ON TIMING AND DURATION. HIGH THAT IFR/LIFR CIGS AND VSBYS RETURN TONIGHT BUT LOW ON TIMING. KMD //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. SOUTHEAST WINDS BCMG SOUTH. THURSDAY...VFR. SOUTH WINDS. FRIDAY...TSRA. MVFR CIGS PSBL OVERNIGHT. SOUTHWEST WINDS. SATURDAY...SCHC TSRA DURING THE DAY AND CHC SHRA. NORTHWEST WINDS. SUNDAY AND MONDAY...CHC TSRA. MVFR CIGS PSBL. NORTHEAST WINDS BCMG SOUTHWEST MONDAY. JEE && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
903 AM CDT TUE MAY 5 2015 .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * SCATTERED RAIN SHOWERS SHIFT EAST OF THE TERMINALS OVER THE NEXT COUPLE OF HOURS. ISOLATED THUNDER GENERALLY SOUTH OF MDW BUT POSSIBLY IN THE 5-10 MILE RANGE. * EAST WINDS 10-11 KT. * IFR CIGS LIFTING TO MVFR * SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN. KMD/JEE //DISCUSSION...UPDATED 12Z... THE RAIN IS SLOWLY SHIFTING NORTHEAST AND WILL CLEAR THE REGION THIS MORNING. NO ADDITIONAL LIGHTNING STRIKES ARE ANTICIPATED WITH THESE SHOWERS. THERE ARE SCATTERED REPORTS OF MVFR CIGS AND THE CIGS SHOULD LIFT TO VFR BEHIND THE SHOWERS. A STATIONARY FRONT WILL REMAIN SOUTH OF THE TERMINALS TODAY AND COULD SEE SHOWERS AND PERHAPS A THUNDERSTORM FIRE ALONG THE FRONT THIS AFTERNOON. THE SHOWERS AND STORMS COULD IMPACT THE EASTERN TERMINALS...BUT DUE TO LOW CONFIDENCE ONLY HAVE A VCSH. THINKING RFD WILL NOT BE IMPACTED. EAST WINDS AT 10 KT DIMINISH TO BELOW 10 KT THIS EVENING AND THEN BEGIN TO BACK TO SOUTHEAST TOMORROW AS THE FRONT LIFTS NORTH. JEE //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN SHOWERS...MEDIUM ON NO ADDITIONAL LIGHTNING THIS MORNING EXCEPT ALONG AND SOUTH OF MDW. * MEDIUM-LOW CONFIDENCE IN OCCURRENCE AND COVERAGE OF -SHRA THIS AFTN. LOW CONFIDENCE IN OCCURRENCE AND COVERAGE OF TSRA. * MEDIUM CONFIDENCE IN IFR CIGS LIFTING TO MVFR BUT LOW ON TIMING AND DURATION. KMD/JEE //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. SOUTHEAST WINDS BCMG SOUTH. THURSDAY...VFR. SOUTH WINDS. FRIDAY...TSRA. MVFR CIGS PSBL OVERNIGHT. SOUTHWEST WINDS. SATURDAY...SCHC TSRA DURING THE DAY AND CHC SHRA. NORTHWEST WINDS. SUNDAY AND MONDAY...CHC TSRA. MVFR CIGS PSBL. NORTHEAST WINDS BCMG SOUTHWEST MONDAY. JEE && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
648 AM CDT TUE MAY 5 2015 .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * RAIN SHIFTS EAST OF THE TERMINALS OVER THE NEXT COUPLE OF HOURS. * EAST WINDS 10-11 KT. * MVFR CIGS LIFT TO VFR AFTER SHOWERS MOVE OUT THIS MORNING. * SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN. JEE //DISCUSSION...UPDATED 12Z... THE RAIN IS SLOWLY SHIFTING NORTHEAST AND WILL CLEAR THE REGION THIS MORNING. NO ADDITIONAL LIGHTNING STRIKES ARE ANTICIPATED WITH THESE SHOWERS. THERE ARE SCATTERED REPORTS OF MVFR CIGS AND THE CIGS SHOULD LIFT TO VFR BEHIND THE SHOWERS. A STATIONARY FRONT WILL REMAIN SOUTH OF THE TERMINALS TODAY AND COULD SEE SHOWERS AND PERHAPS A THUNDERSTORM FIRE ALONG THE FRONT THIS AFTERNOON. THE SHOWERS AND STORMS COULD IMPACT THE EASTERN TERMINALS...BUT DUE TO LOW CONFIDENCE ONLY HAVE A VCSH. THINKING RFD WILL NOT BE IMPACTED. EAST WINDS AT 10 KT DIMINISH TO BELOW 10 KT THIS EVENING AND THEN BEGIN TO BACK TO SOUTHEAST TOMORROW AS THE FRONT LIFTS NORTH. JEE //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN SHOWERS AND NO ADDITIONAL LIGHTNING THIS MORNING. * MEDIUM-LOW CONFIDENCE IN OCCURRENCE AND COVERAGE OF -SHRA THIS AFTN. LOW CONFIDENCE IN OCCURRENCE AND COVERAGE OF TSRA. * MEDIUM-HIGH CONFIDENCE IN CIGS IMPROVING TO VFR THIS MORNING. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. SOUTHEAST WINDS BCMG SOUTH. THURSDAY...VFR. SOUTH WINDS. FRIDAY...TSRA. MVFR CIGS PSBL OVERNIGHT. SOUTHWEST WINDS. SATURDAY...SCHC TSRA DURING THE DAY AND CHC SHRA. NORTHWEST WINDS. SUNDAY AND MONDAY...CHC TSRA. MVFR CIGS PSBL. NORTHEAST WINDS BCMG SOUTHWEST MONDAY. JEE && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
647 AM CDT TUE MAY 5 2015 .SHORT TERM...(TODAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 A FRONTAL BOUNDARY IS ORIENTED WEST-EAST ACROSS CENTRAL IL THIS MORNING WITH PRECIPITATION IN ISENTROPIC ASCENT REGION LARGELY TO THE NORTH OF THE BOUNDARY. MODELS INDICATE THE BOUNDARY AND PRECIPITATION WILL SHIFT SLOWLY NORTHWARD TODAY. WEAK DISTURBANCES MOVING ALONG THE BOUNDARY WILL PRODUCE SOME ENHANCEMENTS IN CONVECTIVE SHOWER COVERAGE IN THE VICINITY...EARLY THIS MORNING FROM AROUND THE ILLINOIS RIVER NORTHWESTWARD...AND LATE IN THE AFTERNOON NORTH OF THE I-74 CORRIDOR. FOR THE MOST PART...CONVECTION SHOULD BE WEAK AT THIS POINT WITH ONLY WEAK MID-LEVEL INSTABILITY REMAINING THROUGH THE NIGHT...AND 0-6KM BULK SHEAR UP TO 25-30 KTS THIS MORNING DIMINISHING SUBSTANTIALLY FOR THE AFTERNOON. 1000-1500 JOULES OF SURFACE-BASED CAPE SHOULD BE ABLE TO DEVELOP WITH AFTERNOON HEATING ALONG/NORTH OF I-72 AND CAN`T RULE OUT ISOLATED THUNDERSTORMS SOUTHWARD TO I-72 AS A RESULT. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 ONGOING CONVECTION ALONG THE BOUNDARY OVER NORTHERN ILLINOIS THIS MORNING NOT ONLY DRIVING THE WEATHER THROUGHOUT THE DAY, BUT INTO THE OVERNIGHT AS WELL. GFS AND NAM CONTINUE TO KEEP A BIT OF PRECIP PRETTY FAR SOUTH, AS FAR SOUTH AS A LINE FROM HAVANA TO BLOOMINGTON. HOWEVER, THE RAP/RUC AND THE HRRR ARE PUSHING THE AREA OF CONVECTION WELL TO THE NORTH THROUGH THE MORNING WITH THE BOUNDARY. WHEN THE SECONDARY WAVE RIPPLES THROUGH THE REGION AFTER 00Z, IT WOULD BE DISPLACED NORTH OF THE FA. THE 4KM WRF HAS JUST THAT SOLUTION, STARTING MORE IN LINE WITH THE RAP/RUC AND HRRR...AND KEEPING THE FA DRY AFTER 00Z, BUT A LITTLE MORE GENEROUS WITH SOME ISOLATED INSTABILITY SHOWERS. HAVE KEPT ISO TS IN THE NORTH, MAINLY ALONG AND NORTH OF I-74 FOR THE EARLY EVENING. HIGH PRESSURE BEGINS TO BUILD BACK INTO THE REGION LATER TONIGHT, SOUTHERLY WINDS PUSHING THE FRONT BACK TO THE NORTH AND OUT OF THE FORECAST AREA THROUGH WED NIGHT. FORECAST REMAINS ROUGHLY THE SAME BEYOND DAY 3... PRECIP CHANCES SLOWLY EDGING BACK INTO WEST CENTRAL ILLINOIS FOR THURSDAY AS AN UPPER LEVEL WAVE PUSHES OUT OF THE SW. THE ENERGY IS PART OF A GENERAL PATTERN SHIFT TO MORE SOUTHWESTERLY FLOW WITH THE UPPER LEVEL TROF DIGGING BACK IN OVER THE SWRN CONUS. THE SFC LOW MOVES OUT INTO THE UPPER MIDWEST AND INTO CANADA BY THE END OF THE WEEK, BUT IN SHIFTING TO MORE SOUTHWESTERLY FLOW ALOFT, OPENS THE DOOR TO A SERIES OF SHORTWAVES THAT KEEP THE FORECAST WET FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND. TEMPS RATHER WARM THROUGH THE FORECAST WITH OVERCAST AND RAINY SKIES KEEPING THE OVERNIGHT LOWS UP A BIT, BUT LIKELY NOT NEARLY AS WARM AS THE TREND IN THE GUIDANCE. HAVE KNOCKED THEM DOWN A COUPLE DEGREES. SOUTHERLY FLOW AND A RELATIVELY WARM AIRMASS KEEPING THE HIGHS A BIT ABOVE NORMS, EVEN WITH THE PASSAGE OF THE FIRST LOW SKIRTING TO THE NW...THE MID LEVELS REMAIN WARM UNTIL THE MAIN TROF OVER THE SW LIFTS INTO AND OUT OF THE GREAT LAKES. COOLER AIR IN THE MIDLEVELS IS ONLY AROUND FOR 36 HOURS DAY 7/8 BEFORE THE WARM AIRMASS REESTABLISHES ITSELF. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 647 AM CDT TUE MAY 5 2015 SHOWERS HAVE MOVED OUT OF CENTRAL IL TAF SITES THIS MORNING WITH VFR CONDITIONS AT MOST SITES...AREAS BKN060-080 CIGS...AND IFR- LIFR CONDITIONS IN FOG AT SITES FROM KPIA-KC75 NORTHWESTWARD. FOG WILL DISSIPATE WITH DAYTIME HEATING IN A FEW HOURS. ALSO WITH DAYTIME HEATING...EXPECTING ISOLD TSRA DEVELOPING FROM AROUND 18Z-24Z. SCT-BKN CLOUD COVER SHOULD DEVELOP AS WELL GENERALLY ABOVE MVFR THRESHOLDS. PROBABILITY OF DEVELOPMENT AND TIMING UNCERTAINTY PREVENT EXPLICIT MENTION OF TSRA IN CENTRAL IL TAFS...HOWEVER MVFR OR WORSE CIGS/VSBYS POSSIBLE IN ISOLATED STORMS. INSTABILITY DECREASING OVERNIGHT SHOULD BRING AN END TO ANY STORMS SHORTLY AFTER SUNSET. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ONTON LONG TERM...HJS AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
627 AM EDT TUE MAY 5 2015 .SYNOPSIS... A SLOW MOVING FRONTAL BOUNDARY WILL KEEP RAIN CHANCES IN THE FORECAST THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... CURRENT RADAR IMAGERY SHOWS A MASS OF SHOWERS CONGEALING OVER EASTERN OHIO...PUSHING SLOWLY TO THE EAST. THIS ACTIVITY IS LOCATED ALONG AND JUST SOUTH OF THE CURRENT WEAK SURFACE FRONT...ORIENTED WITH HIGHER MOISTURE CONTENT. EXPECTING THESE SHOWERS TO REACH THE PITTSBURGH METRO WITHIN THE NEXT TWO HOURS BRINGING LIGHT RAIN FOR THE MORNING COMMUTE. HRRR HAS HAD A GOOD HANDLE ON THIS REMNANT SHOWER ACTIVITY OVER THE LAST SEVERAL HOURS...AND THUS WAS FOLLOWED THROUGH MID-MORNING. BROAD FRONTAL ZONE AND DEEPER MOISTURE WILL SHIFT NORTH SOME THROUGH MIDDAY AS A WAVE CURRENTLY NEARING LAKE MICHIGAN TRACKS THROUGH THE SOUTHERN GREAT LAKES. THIS WILL SHIFT THE FOCUS OF ANY AFTERNOON SHOWER OR THUNDERSTORM ACTIVITY NORTH AS WELL. HI- RES MODELS THAT ARE HANDLING THE CURRENT TRENDS WITH SOME SUCCESS...HAVE BEEN LESS THAN EXCITED ABOUT CONVECTIVE DEVELOPMENT THIS AFTERNOON...TO THE POINT OF VERY LITTLE PRECIPITATION ACROSS THE FORECAST AREA. STILL THINKING MODELS ARE UNDERPRODUCING...GIVEN THE AVAILABILITY OF MOISTURE AND THE AT LEAST MARGINAL INSTABILITY NOTED IN THE AFTERNOON SOUNDINGS. WILL MAINTAIN CHANCE TO LIKELY POPS NORTH OF PITTSBURGH. MODEL GUIDANCE HAS TRENDED FURTHER NORTH WITH THE TRACK OF THE UPPER-LEVEL WAVE TONIGHT...AS THE RIDGE OF HIGH PRESSURE RE-BUILDS IN THE MID-WEST. MODIFICATIONS WERE MADE TO PUSH TONIGHTS RAIN CHANCES WELL NORTH OF PREVIOUS FORECAST. SOME OF OUR SOUTHERN AND WESTERN ZONES SHOULD EVEN GET SOME CLEARING HEADING INTO TONIGHT WITH THE FOCUS OF DEEPER MOISTURE SHIFTING NORTH. TAX && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... RIDGING STARTS TO BUILD OVER THE OHIO VALLEY DURING THE DAY ON WEDNESDAY. THIS WILL DROP H500 HEIGHTS ACROSS THE CWA IN RESPONSE AND HELP TO SAG THE FRONTAL BOUNDARY A BIT FURTHER SOUTH DURING THE DAY. FOCUSED HIGHER POPS IN SOUTHERN PORTIONS OF CWA DURING THE AFTERNOON. ENOUGH INSTABILITY IS PRESENT FOR THE CONTINUED CHANCE OF THUNDER AS WELL. KEPT POPS IN CHANCE CATEGORY WITH CONTINUED UNCERTAINTY AS TO FRONTAL EVOLUTION. AS RIDGE STARTS TO BUILD EASTWARD...FRONTAL BOUNDARY WILL BECOME MORE DIFFUSE WITH TIME. ALLOW POPS TO FALL OFF DURING THE EVENING HOURS WITH LOSS OF HEATING. H500 RIDGE IS IN CONTROL FOR THE REMAINDER OF THIS PERIOD...WITH THE RIDGE AXIS PASSING BY AROUND 00Z FRIDAY. GFS/ECMWF BOTH PAINT SOME DIURNAL QPF ACROSS THE AREA THURSDAY AND FRIDAY AFTERNOONS. THINK THAT THIS IS OVERDONE FOR THE MOST PART AS AT LEAST MODEST CAPPING SHOULD BE PRESENT UNDER THE RIDGE. EXCEPTION COULD BE ALONG THE EASTERN RIDGES WITH MODEST UPSLOPE FLOW...AND KEPT AN AFTERNOON/EVENING SLIGHT CHANCE BOTH AFTERNOONS IN THIS AREA. OTHERWISE...DRY AND WARM CONDITIONS WILL PERSIST. A SLOW WARMING TREND WILL SEE TEMPERATURES RISE BACK INTO THE LOWER AND MID 80S FOR MOST AREAS BY FRIDAY. CL && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... UPPER RIDGE GETS SLOWLY DISLODGED WITH TIME AS ENERGY EJECTS FROM WESTERN U.S. TROUGH AND TOWARDS THE UPPER MISSISSIPPI VALLEY BY 00Z MONDAY. RESULTING SURFACE LOW AND FRONTAL SYSTEM WILL ADVANCE EASTWARD WITH TIME...PERHAPS ARRIVING MONDAY NIGHT OR TUESDAY. AHEAD OF THIS...MAINLY DIURNAL POPS GET A BIT HIGHER EACH DAY WITH THE DEPARTURE OF THE RIDGE. RIPPLES ALONG THE BACK SIDE OF THE RIDGE MAY PROVIDE LOCALIZED ENHANCEMENT...WHICH OF COURSE ARE TOUGH TO TIME AT THIS DISTANCE. THE FRONT BRINGS MORE GENERALIZED PRECIPITATION CHANCES MONDAY INTO TUESDAY. FAIRLY STATIC ABOVE NORMAL TEMPERATURES ARE FORECAST FRIDAY NIGHT THROUGH MONDAY NIGHT...WITH HIGHS IN THE 80S AND LOWS ON EITHER SIDE OF 60. COOLER TEMPERATURES MAY ARRIVE TUESDAY WITH THE FRONT. CL && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... VISIBILITY RESTRICTIONS THIS MORNING HAVE BEEN CONFINED TO A SELECT FEW TERMINALS WHERE AT LEAST SOME CLEARING HAD TAKEN PLACE...AND FOG WAS ABLE TO FORM. ANY REMAINING RESTRICTIONS DUE TO FOG SHOULD END QUICKLY AFTER SUNRISE WITH MIXING AND AS A BROADER CLOUD SHIELD MOVES IN. ADDITIONALLY...AN AREA OF SHOWERS IS MOVING ALONG THE BROAD FRONTAL ZONE...AND ARE CURRENTLY THROUGH EASTERN OHIO. NOT EXPECTING MUCH FURTHER EXPANSION OR STRENGTHENING OF THESE SHOWERS THROUGH MID-MORNING...BUT THEY COULD BRING TEMPORARY VISIBILITY RESTRICTIONS AS THEY SLOWLY MOVE EAST ACROSS HLG/BVI/PIT/AGC. LATER TODAY...HAVE THIS LINE OF SHOWERS LIFTING NORTH WITH THE BROAD FRONTAL ZONE WHERE INSTABILITY THIS AFTERNOON COULD DRIVE ADDITIONAL SHOWERS/THUNDERSTORMS. HAVE INCLUDED VCTS FOR NORTHERN AND EASTERN TAF SITES...BUT SPATIAL EXTENT OF THUNDERSTORM ACTIVITY SHOULD BE FAIRLY LIMITED. TAX .OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/... SCATTERED RESTRICTIONS IS A POSSIBILITY EARLY WEDNESDAY AS FRONTAL BOUNDARY SLOWLY DECAYS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1034 AM EDT TUE MAY 5 2015 .UPDATE... THE DETAILED FORECAST REASONING PROVIDED IN THE EARLY MORNING DISCUSSION WAS WELL DONE AND REMAINS VALID. A MATURE MCS AND COMPLEX OF SHORTWAVE ENERGY SUPPORTED BY RIGHT ENTRANCE REGION DYNAMICS ALOFT IS CURRENTLY LIFTING INTO SOUTHEASTERN MICHIGAN THIS MORNING. SURFACE PRECIPITATION REPORTS SUPPORT LIGHT TO MODERATE RAIN OCCURRING WITHIN THE FORWARD...WARM AIR ADVECTION QUADRANTS OF THE MCS. WITH THE RAIN MOVING IN...SOUTHEASTERN MICHIGAN CAN EXPECT CATEGORICAL/PERIODS OF RAIN THROUGHOUT THE AFTERNOON HOURS. FORECAST UNCERTAINTY FOR THE SHORT TERM PERIOD CENTERS ON WHEN EXACTLY SYNOPTIC SUPPORT/RAIN WILL END OVER THE AREA. LATEST NAM AND RAP ARE REALLY PAINTING DIFFERENT PICTURES. NAM SUGGESTS SUBSIDENCE IN THE WAKE OF THIS MCS...MAY BRING A QUIET PERIOD EARLY THIS EVENING...WHILE THE RAP DRAGS OUT THE DURATION OF THIS CATEGORICAL RAIN INTO THE EVENING. THERE REMAINS A WINDOW OF OPPORTUNITY FOR SOME THUNDER CHANCES LATE THIS AFTERNOON...POST 20Z. THOSE CHANCES APPEAR TO HINGE ON THE LIKELIHOOD OF THE NAM SOLUTION VERIFYING. NEGLIGIBLE CONVECTIVE INSTABILITY YIELDS NO SUPPORT FOR SEVERE THUNDERSTORM POTENTIAL. && .AVIATION...ISSUED 707 AM EDT TUE MAY 5 2015 A NOTABLE DECREASE IN LIGHTNING WITHIN ONGOING ACTIVITY MOVING IN FROM THE WEST FOR THE MORNING. A FEW STRAY LIGHTNING STRIKES WILL BE POSSIBLE BUT MORE LIKELY AN MVFR RESTRICTION DUE TO A HEAVIER DOWNPOUR OF RAIN. EXPECT MVFR RESTRICTION DUE TO LOW VISIBILITY IN SHOWERS INITIALLY...ESPECIALLY PTK TO FNT WHERE THE MOST PERSISTENT RAIN WILL SET UP...AND THEN MVFR DUE TO LOW CEILING LATER TODAY AND THIS EVENING. IFR CEILING IS THEN LIKELY OVERNIGHT INTO WEDNESDAY MORNING AS THE SURFACE FRONT DRIFTS NORTHWARD FROM INDIANA AND OHIO. FOR DTW... SHOWERS WILL MOVE INTO THE TERMINAL AREA SHORTLY AFTER ISSUANCE TIME AND THEN PERSIST THROUGH THE MORNING. THE HEAVIEST AND MOST FREQUENT ACTIVITY WILL THEN SHIFT NORTH DURING THE AFTERNOON. THERE IS A LATE AFTERNOON OR EARLY EVENING WINDOW FOR THUNDERSTORMS BUT THIS WILL DEPEND ON THE EXTENT OF DEVELOPMENT ALONG THE SURFACE FRONT DURING PEAK DAYTIME HEATING. OTHERWISE...CEILING WILL LOWER STEADILY INTO MVFR THROUGH THE EVENING AND THEN IFR OVERNIGHT THROUGH WEDNESDAY MORNING AS THE SURFACE FRONT DRIFTS CLOSER FROM INDIANA AND OHIO. //DTW THRESHOLD PROBABILITIES... * HIGH FOR CEILING BELOW 5000 FT TODAY AND TONIGHT. * LOW FOR THUNDERSTORMS TODAY AND TONIGHT. && .PREV DISCUSSION...ISSUED 355 AM EDT TUE MAY 5 2015 SHORT TERM... TODAY AND TONIGHT A WET 24 HOUR PERIOD IS SETTING UP OVER SOUTHERN LOWER MICHIGAN TODAY THROUGH TONIGHT. THE TRI CITIES AND NORTHERN THUMB MAY ESCAPE THE BULK OF THE RAINFALL TODAY BUT THE REST OF SE MICHIGAN STANDS TO PICK UP A PROLONGED PERIOD OF SHOWERS AND THUNDERSTORMS. THE SURFACE FRONT WILL REMAIN SOUTH OF THE OHIO BORDER THROUGH THE PERIOD SO THUNDERSTORMS WILL BE THE ELEVATED VARIETY AND MAINLY CONTRIBUTE TO LOCALLY HEAVY DOWNPOURS. RAINFALL TOTALS LOCALLY AROUND 1 INCH WILL BE POSSIBLE BY SUNRISE WEDNESDAY. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE ALREADY UNDERWAY OVER THE MIDWEST AND WILL SPREAD TO THE NORTH AND EAST DURING THE REST OF THE MORNING. THIS AREA OF CONVECTION ORIGINATED ALONG THE FRONT OVER THE CENTRAL PLAINS DURING PEAK HEATING YESTERDAY AND HAS SINCE GROWN LARGE ENOUGH AND PERSISTENT ENOUGH TO SUPPORT MCV DEVELOPMENT ALOFT AND AN AREA OF SURFACE PRESSURE FALLS OVER IOWA AND MISSOURI. THE WAVE IS JUST STRONG ENOUGH TO SUPPORT A WEAK LOW LEVEL JET FUELING ACTIVITY OVER NORTHERN ILLINOIS WHICH WILL CONTINUE TO DEVELOP INTO SOUTHERN LOWER MICHIGAN AS THE LOW TO MID LEVELS OF THE FRONT STRENGTHEN WITH TIME. CONVECTIVE DEBRIS IN SATELLITE IMAGERY SHOWS THE ENTRANCE REGION OF A 120 KNOT UPPER JET ANALYZED IN MODEL DATA AT 250 MB. THIS FEATURE IS POSITIONED FAVORABLY OVER THE GREAT LAKES TO GENERATE STRONG FRONTOGENESIS THROUGH TODAY WHILE THE LARGE SCALE FRONTAL POSITION REMAINS STATIONARY AND THEN DRIFTS SLOWLY NORTHWARD TONIGHT. CROSS SECTIONS OF MODEL DATA FROM THE POSITION OF THE SURFACE FRONT EXTENDING NORTHWARD TO THE UPPER JET AXIS SHOW THE STEEPEST PORTION OF THE AGEOSTROPHIC CIRCULATION SETTING UP THROUGH CENTRAL SECTIONS OF OUR AREA BY AFTERNOON THROUGH THIS EVENING. DEEP CONVECTIVE INSTABILITY ABOVE THE FRONTAL SURFACE COMBINED WITH PRECIPITABLE WATER RISING TO ABOUT 1.25 INCHES WILL ENSURE WIDESPREAD COVERAGE OF SHOWERS WITH EMBEDDED THUNDERSTORMS. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE DUE TO THE PERSISTENCE OF THIS TEXTBOOK UPPER JET ENHANCED FRONTAL CIRCULATION AND THE CONVECTIVE NATURE OF THE PRECIPITATION PATTERN. SO THEN WHAT COULD GO WRONG IN THIS FORECAST? THE POTENTIAL FOR SURFACE BASED CONVECTION OVER INDIANA AND OHIO...COMBINED WITH THE TENDENCY FOR ELEVATED INSTABILITY TO BECOME LESS EFFECTIVE DURING THE DAY...COULD LEAD TO A WEAKENING TREND IN THE PATTERN OVER SE MICHIGAN DURING THE AFTERNOON INTO THIS EVENING. SHOULD THIS OCCUR...IT WOULD DO MORE TO REDUCE THE POTENTIAL FOR HEAVY RAINFALL IN OUR AREA AND POSSIBLY ALTER THE LOCATION OF THE MOST PERSISTENT SHOWERS AND OVERALL QPF... BUT MOST AREAS WILL SEE A LENGTHY PERIOD OF RAIN AS THE MORNING RAMP UP WOULD CARRY OVER INTO THE AFTERNOON JUST BASED ON INERTIA. PROGRESSION OF THE UPPER LEVEL RIDGE AND THE ENTRANCE REGION OF THE UPPER JET WILL NUDGE THE MID LEVEL FRONTAL ZONE TO THE NORTH AND EAST OVERNIGHT. THIS WILL BRING THE TRI CITIES AND NORTHERN THUMB MORE INTO THE PATTERN OF REMAINING SHOWERS AND WILL BE THE FAVORED LOCATION FOR ANY NOCTURNAL REDEVELOPMENT. THE AXIS OF LIKELY POPS OVER SE MICHIGAN IS PLACED ALONG THE 850 MB THETA-E GRADIENT WHICH IS WELL AGREED UPON BY THE 00Z MODEL CYCLE AND IS THE MOST FAVORED LOCATION FOR RENEWED DEVELOPMENT OF NOCTURNAL ELEVATED INSTABILITY AND SUPPORT FOR SHOWERS THROUGH SUNRISE WEDNESDAY. LONG TERM...WEDNESDAY THROUGH MONDAY SE MICHIGAN WILL RESIDE ALONG THE IMMEDIATE DOWNSTREAM SIDE OF AN ELONGATING UPPER RIDGE ON WEDNESDAY. THE RESULTING WEAKLY SHEARED WEST-NORTHWEST FLOW WILL SUSTAIN A PERTURBED 850-925 MB FRONTAL ZONE ACROSS THE REGION. MODELS TRENDING SLIGHTLY STRONGER WITH THE ASCENT/CONVERGENCE THROUGH THIS LAYER...SUGGESTING THE EXISTING FRONTAL SLOPE WILL POTENTIALLY BE MORE ACTIVE. THIS WILL SUPPORT THE INCLUSION OF A LOWER END POP. GREATER POTENTIAL FOR SHOWER PRODUCTION DURING THE MORNING PERIOD...BEFORE BOTH THE MOISTURE QUALITY AND AVAILABLE FORCING DIMINISHES AS THE INBOUND UPPER RIDGE MAKES BETTER INROADS. SUBSTANTIAL CLOUD COVER WITHIN PERSISTENT LOW LEVEL EASTERLY FLOW WILL CAP THE DIURNAL TEMPERATURE RESPONSE TO SOME DEGREE...REGARDLESS OF SHOWER COVERAGE. ABSENT OF A LARGER AND PERSISTENT COVERAGE OF SHOWERS TO DISRUPT THE HEATING CYCLE... EXISTING THERMAL PROFILE WILL SUPPORT HIGHS GENERALLY WITHIN THE MID AND UPPER 60S RANGE. UPPER RIDGE STEADILY BUILDS INTO LOWER MICHIGAN WEDNESDAY NIGHT... 580 DM AT 500 MB MARKING THE RIDGE AXIS CENTERING OVERHEAD BY EARLY THURSDAY MORNING. THIS PROGRESSION WILL SEND SE MICHIGAN INTO THE WARM SECTOR BY THURSDAY...SOLID DEPTH TO THE EMERGING SOUTHWEST FLOW CONTINUING TO POINT TOWARD HIGHS MAKING A RUN INTO THE LOWER 80S. DRY/STABLE PROFILE STILL INFLUENCED BY EXITING UPPER RIDGING WILL RESULT IN LITTLE MORE THAN A STANDARD DIURNAL CU FIELD. CLOSED LOW CURRENTLY PARKED OVER THE DESERT SOUTHWEST WILL LIFT NORTHEAST THROUGH THE LATTER HALF OF THE WEEK...EVENTUALLY SHEARING OVER THE TOP OF THE UPPER RIDGE STAGNATING ALONG THE EAST COAST. THIS LOWERING HEIGHT FIELD WILL BEGIN TO EASE AN ATTENDANT FRONTAL BOUNDARY EASTWARD WITHIN THE FRIDAY AND SATURDAY WINDOW. GENERAL TIMING ACROSS THE MODEL SPECTRUM SUGGESTS FRIDAY WILL REMAIN CHARACTERED BY THE PRE-FRONTAL WARM SECTOR...WITH ANY POSSIBLE LATE DAY/EVENING CONVECTIVE CHANCES ARRIVING TOO LATE TO DISRUPT ANOTHER DAY WITH HIGHS IN THE 80S. POTENTIAL IS THERE FOR AN ACTIVE PERIOD HEADING INTO THE UPCOMING WEEKEND...FRONTAL BOUNDARY EVENTUALLY ALIGNING OVER OR NEAR THE REGION FOR AN EXTENDED TIME AS THE AXIS BECOMES PARALLEL TO THE MEAN FLOW. THIS PATTERN WOULD SHAVE A FEW DEGREE OFF PROSPECTIVE HIGHS THIS WEEKEND RELATIVE TO THE THU/FRI WARMTH...STILL NEAR TO ABOVE NORMAL THROUGH THIS TIME. MARINE... SHOWERY CONDITIONS WITH THE CHANCE OF THUNDERSTORMS WILL EXIST UNDER PERSIST EAST TO NORTHEAST FLOW OVER THE SOUTHERN LAKE HURON BASIN AND POINTS SOUTHWARD THROUGH TONIGHT. FAVORABLE MARINE CONDITIONS ACROSS NORTHERN LAKE HURON DURING THIS TIME AS HIGH PRESSURE BUILDS INTO THE REGION. MODEST WAVE AND WIND CONDITIONS THROUGH THE MIDWEEK PERIOD AS HIGH PRESSURE SUSTAINS A WEAK GRADIENT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......CB AVIATION.....BT SHORT TERM...BT LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
734 AM EDT TUE MAY 5 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 503 AM EDT TUE MAY 5 2015 WV IMAGERY AND RUC ANALYSIS INDICATED CONFLUENT WRLY MID/UPPER LEVEL FLOW INTO THE NRN GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE SE CONUS INTO THE CNTRL PLAINS. WITH A SFC RIDGE EXTENDING FROM NW ONTARIO THROUGH THE NRN LAKES...LIGHT WINDS AND CLEAR SKIES OVER UPPER MI HAS ALLOWED TEMPS TO DROP OFF INTO THE MID AND UPPER 30S WITH SEVERAL INLAND COLD SPOTS IN THE UPPER 20S TO AROUND 30. CLOUDS AND TODAY...EXPECT THAT HIGH PRES WILL CONTINUE TO DOMINATE AS THE CLOUDS AND PCPN ASSOCIATED WITH A FRONTAL BOUNDARY FROM SRN IA INTO NRN IL REMAIN WELL TO THE SOUTH. MIXING TO 5K FT WITH 850 MB TEMPS FCST IN THE 6C TO 8C RANGE WILL SUPPORT HIGHS IN THE UPPER 60S TO AROUND 70...EXCEPT ALONG THE GREAT LAKES WHERE READING WILL REMAIN IN THE UPPER 50S AND LOWER 60S. SIMILAR TO MONDAY...AFTERNOON DEWPOINTS WILL DROP INTO THE LOWER 20S WITH RH VALUES FROM 15 TO 20 PCT. HOWEVER...WINDS WILL REMAIN LIGHT...AOB 10 MPH. TONIGHT...AS THE HIGH SHIFTS OFF TO THE EAST AND AND 850 MB WARM FRONT APPROACHES FROM THE SOUTH...EXPECT INCREASING CLOUDS OVERNIGHT. THIS WILL KEEP TEMPS FROM FALLING OFF AS MUCH WITH MIN READINGS IN THE UPPER 30S TO AROUND 40. WITH THE VERY DRY AIRMASS IN PLACE...THE SLOWER END OF GUIDANCE WAS FAVORED WITH THE PCPN ADVANCING FROM THE SOUTH. SO...NO PCPN MENTION WAS INCLUDED. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 438 AM EDT TUE MAY 5 2015 ABOVE AVERAGE TEMPS WILL CONTINUE THROUGH THE WEEK AMIDST SMALL CHANCES OF PRECIP WEDNESDAY...AND A CHANCE OF SHOWERS AND STORMS LATE THURSDAY INTO FRIDAY. MUCH COOLER WEATHER WILL THEN RETURN FOR THE WEEKEND. WEDNESDAY AND WEDNESDAY NIGHT...A STOUT MID-LEVEL RIDGE WILL BE ENTERING THE WESTERN CWA AT 12Z WED AS AN ASSOCIATED SFC HIGH OVER GEORGIAN BAY SHIFTS SOUTHEASTWARD. MEANWHILE...A SHORTWAVE TROUGH DRIFTING NE FROM THE SOUTHERN ROCKIES WILL BEGIN TO CONSOLIDATE A BROAD SFC TROUGH ALONG THE ENTIRE U.S. ROCKIES. MODELS CONTINUE THEIR TWO-DAY TREND IN LOWERING QPF ALONG AN 850 HPA WARM FRONT ACROSS THE SW CWA WED MORNING. IN FACT...MOST OF THE HIGHER-RES GUIDANCE SUITE SHOWS VERY LITTLE PRECIP DURING THE DAY WEDNESDAY. THE STEEP MID-LEVEL RIDGE IS PROVING TO BE TOO MUCH TO MAINTAIN MOST OF THE INCOMING RAIN SHOWERS FROM WI. ADDITIONALLY...THE BULK OF THE BETTER LOW-LEVEL MOISTURE WILL REMAIN ACROSS MN. HAVE THUS OPTED TO CUT NEARLY ALL CHANCES OF PRECIP EXCEPT FOR A SLIGHT CHANCE FOR SHOWERS ALONG THE WI BORDER IN THE MORNING. THURSDAY THROUGH FRIDAY...AFTER THE H8 WARM FRONT CROSSES THE CWA...THERE IS LITTLE SUPPORT FOR PRECIP UNTIL AT LEAST THURSDAY AFTERNOON. ADDITIONALLY...CAPPING AROUND 750 HPA SHOULD KEEP PRECIP CHANCES LIMITED THROUGH THURSDAY MORNING. THE SFC COLD FRONT UNDER INCREASING MOISTURE FROM AN H8 50KT JET AND A DEVELOPING LEFT-EXIT OF A WEAK UPPER JET STREAK SHOULD BE ENOUGH TO RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS LATE THU AFTERNOON THROUGH MUCH OF THU NIGHT. HOWEVER...KEPT POPS AT JUST A CHANCE OF SHOWERS AND THUNDERSTORMS AS THE BEST MID-LEVEL FORCING PEELS OFF TO THE NORTH. TEMPS COULD GET QUITE WARM THU IF ENOUGH AFTERNOON CLEARING OCCURS. GIVEN THE CAP...THINK THERE WILL BE ENOUGH INSOLATION TO BOOST TEMPS INTO THE LOW 80S ACROSS THE WEST UNDER H8 TEMPS UP TO 14C. IN ADDITION TO THE WARMER WX...MIXING INTO 35 TO 45KT WINDS SHOULD RESULT IN QUITE A GUSTY DAY...ESPECIALLY WEST. EVEN THOUGH MUCH OF WEST DID NOT BENEFIT FROM SATURDAYS PRECIP...FIRE WX CONCERNS SHOULD BE PARTIALLY MITIGATED BY INCREASING LOW-LEVEL MOISTURE...RESULTING IN MIN RH VALUES ONLY INTO THE UPPER 30S. HOWEVER...FIRE INDICES ARE BEGINNING TO INDICATE INCREASING FIRE POTENTIAL ACROSS THE WEST...SO THURSDAY WILL NEED TO BE MONITORED IF LOW-LEVEL MOISTURE IS SLOW TO ARRIVE. FRIDAY...THE COLD FRONT LOOKS TO CLEAR THE CWA BY FRIDAY AFTERNOON...ENDING PRECIP CHANCES AND USHERING IN COOLER AIR. TEMPS WILL DROP ALONG PORTIONS OF LAKE SUPERIOR DURING THE AFTERNOON HOURS AS WINDS BECOME NW. SATURDAY...THE ECMWF AND CANADIAN GEM STRUGGLE TO PUSH THE COLD FRONT FAR AWAY FROM THE CWA...LEAVING LINGERING CHANCES OF SHOWERS ACROSS THE SE HALF. THE GFS KEEPS THE AREA DRY...AND GIVEN ITS BETTER RUN TO RUN CONSISTENCY WITH THIS SYSTEM...HAVE OPTED TO KEEP NEARLY ALL POPS OUT OF THE CWA. HOWEVER...SOME SPRINKLES/DRIZZLE CANNOT BE RULED OUT ALONG LAKE SUPERIOR...WHERE N WINDS AND LINGERING LOW-LEVEL MOISTURE SHOULD RESULT IN DECENT LOW-LEVEL CLOUDS. ADDITIONALLY...TEMPS WILL LIKELY STRUGGLE TO REACH 50F NEAR THE SHORE. SUNDAY AND MONDAY...MODEL DIFFERENCE QUICKLY DEVELOP WITH THE HANDLING OF A DEEP TROUGH EXITING THE WESTERN CONUS. FOLLOWING THE GFS SOLUTION...A SFC LOW IN THE LEE OF THE ROCKIES WILL TRACK ENE ALONG THE STALLED W TO E SFC BOUNDARY BIFURCATING THE CENTRAL CONUS. THE ECMWF AND CANADIAN GEM TRACK THE LOW FARTHER NORTH. ABUNDANT CONVECTION ACROSS THE PLAINS ONLY LEADS TO MORE UNCERTAINTY WITH THE SYNOPTIC EVOLUTION OF THIS SYSTEM...SO HAD TO RESORT TO USING CONSENSUS CHANCE POPS SUNDAY AFTERNOON THROUGH MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 732 AM EDT TUE MAY 5 2015 WITH DRY HIGH PRESSURE DOMINATING...EXPECT VFR CONDITIONS AND LIGHT WINDS AT ALL 3 TAF SITES THIS FCST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 503 AM EDT TUE MAY 5 2015 AS A TROUGH MOVES FROM THE PLAINS TO THE UPPER MS VALLEY...SRLY WINDS WILL INCREASE TO AROUND 25 KNOTS OVER THE EAST BY LATE THU INTO THU NIGHT. OTHERWISE...WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
954 AM MDT TUE MAY 5 2015 .UPDATE... MINOR ADJUSTMENTS TO THE GOING FORECAST TODAY. AREA WILL BE UNDER A SOUTHERLY FLOW REGIME TODAY AHEAD OF TONIGHTS COLD FRONT. A COUPLE OF DISTURBANCES CROSSING SOUTH TO NORTH OVER WESTERN ZONES THIS AFTERNOON WILL TRIGGER ISOLATED TO SCATTERED THUNDERSTORMS. SHEAR PROFILES AND INSTABILITY LOOK WEAK SO NOT EXPECTING ANY SEVERE STORMS BUT COULD SEE AN ISOLATED STRONG WIND GUST WITH THIS ACTIVITY. LOOKS LIKE THIS MORNING WILL BE MAINLY DRY SO DROPPED MOST POPS BEFORE NOON. ALSO REMOVED MENTION OF AFTERNOON POPS FOR SOUTHEAST MONTANA AS IT LOOKS CONVECTION WILL HOLD OFF UNTIL LATER IN THE EVENING THERE. LOWERED RH/TD VALUES A BIT AS WELL AHEAD OF THE FRONT. REST OF THE FORECAST IN PRETTY GOOD SHAPE. CHAMBERS && .SHORT TERM...VALID FOR TDY AND WED... UNSETTLED WEATHER BEGINS TODAY AND WILL CONTINUE RIGHT THROUGH THE REMAINDER OF THE WEEK. AN UPPER LOW AND TROUGH WILL MOVE ONTO THE PACIFIC NORTHWEST COAST TODAY AND REMAIN STATIONARY OR SLOWLY SHIFT SOUTHEAST TOWARD THE GREAT BASIN AREA DURING THE DAY WEDNESDAY. THIS WILL ALLOW A SOUTHWEST FLOW ALOFT TO BEGIN TO DEVELOP OVER OUR AREA TODAY AND ESPECIALLY BE IN PLACE FOR WEDNESDAY. SEVERAL SURFACE LOWS WILL DEVELOP ACROSS THE NORTHERN AND CENTRAL ROCKIES BRINGING A PREDOMINATELY SOUTHEAST SURFACE FLOW ALLOWING FOR INCREASING LOW-LEVEL MOISTURE ACROSS THE AREA THROUGH WEDNESDAY. MODELS INCLUDING THE HRRR BRING A VORT MAX OVER OUR AREA TODAY RESULTING IN SHOWERS AND ISOLATED THUNDERSTORMS. SHEAR IS A BIT BETTER TODAY BUT STILL NOT IMPRESSIVE. CAPES ARE ALSO SLIGHTLY BETTER TODAY AND MORE WIDESPREAD SO THUNDERSTORM CHANCES WILL BE BETTER TODAY THAN TUESDAY. PRE-FRONTAL WARMING TODAY WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 70S TO AROUND 80 DEGREES A COLD FRONT WILL MOVE ACROSS THE FORECAST AREA WEDNESDAY MORNING USHERING IN GUSTY NORTHWEST WINDS BY AFTERNOON ALONG WITH A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS. TEMPERATURES WILL BE MUCH COOLER WITH READINGS ONLY IN THE LOWER TO MIDDLE 60S SO INSTABILITY FOR THUNDERSTORMS WILL NOT BE AS GOOD AS TODAY. A STRONGER DISTURBANCE AND UPPER LOW WILL MOVE NORTHEAST OUT OF WYOMING WEDNESDAY INTO WEDNESDAY NIGHT. MODELS SHOW GOOD WRAP- AROUND MOISTURE WITH THIS ALONG WITH DECENT QPF AMOUNTS. AS A RESULT...HAVE INCREASED POPS INTO THE LIKELY AND CATEGORICAL RANGE DURING THIS TIME FROM CUSTER AND POWDER RIVER COUNTIES EASTWARD. ELSEWHERE...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS. HOOLEY .LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON... LATEST MODEL RUNS HAVE CONTINUED TO KEEP THE BULK OF THE ENERGY AND MOISTURE OUT OF THE THE AREA. MODELS HAVE CONTINUED TO TRACK WELL WITH EACH OTHER...WITH THE 00Z DATA HAVING MORE OF A CLOSED LOW EJECTING FROM THE GREAT BASIN THIS WEEKEND...BUT IT TRACKS MORE INTO THE CENTRAL PLAINS. THIS HAS THE EFFECT OF KEEPING THE BULK OF THE MOISTURE AND ENERGY SOUTH OF MONTANA. CONTINUE TO SEE DIFFLUENT FLOW ALOFT ACROSS THE AREA THIS WEEKEND...ALONG WITH SOME MID-LEVEL MOISTURE. THIS WILL KEEP AT LEAST A CHANCE OF LIGHT SCATTERED PRECIP ACROSS THE AREA. HAVE TRENDED POPS DOWN SOME GIVEN THE TREND AWAY FROM A MORE FAVORABLE SOLUTION. THE COLUMN IS NOT OVERLY SATURATED...WITH PRECIPITABLE WATER VALUES ONLY AROUND A HALF INCH. THE POTENTIAL FOR MUCH ACCUMULATION REMAINS LOW. WITH THE MID LEVEL MOISTURE...MUCH OF THE EXTENDED PERIOD WILL BE CLOUDY...THUS COOLER. TEMPERATURES CONTINUE BE IN THE 50S FOR HIGHS. REIMER && .AVIATION... VFR CONDITIONS WILL PREVAIL THIS MORNING. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP FROM ROUNDUP TO KBIL TO KSHR W THIS AFTERNOON...AND CONTINUE INTO EARLY EVENING. THE PRECIPITATION WILL PRODUCE MVFR/IFR CONDITIONS. AREAS OF MOUNTAIN OBSCURATION WILL DEVELOP THIS AFTERNOON. PRECIPITATION WILL BECOME MORE WIDESPREAD THIS EVENING AS A COLD FRONT PUSHES INTO THE AREA BRINGING A WIND SHIFT TO THE NW AT KLVM BY 06Z. THE THREAT FOR THUNDER WILL DECREASE LATE THIS EVENING. SCATTERED SHOWERS ARE EXPECTED LATE TONIGHT. MVFR TO IFR CONDITIONS WILL CONTINUE WITH THE PRECIPITATION TONIGHT...WITH AREAS OF MOUNTAIN OBSCURATION. THE COLD FRONT WILL REACH KMLS BY 12Z WED. ARTHUR && .PRELIMINARY POINT TEMP/POPS... TDY WED THU FRI SAT SUN MON ------------------------------------------------------- BIL 079 049/059 040/053 040/053 039/051 038/059 040/060 2/T 43/W 22/W 24/W 55/W 43/W 32/W LVM 076 043/061 036/050 034/048 034/050 034/059 035/060 3/T 64/W 35/W 35/W 55/W 43/W 33/W HDN 082 050/061 042/056 038/057 039/053 037/059 035/062 1/B 34/W 22/W 23/W 55/W 43/W 32/W MLS 079 051/060 041/055 037/056 038/054 037/057 038/061 1/B 38/W 42/W 12/W 44/W 43/W 32/W 4BQ 075 051/061 043/055 035/055 039/052 035/053 034/059 1/B 48/T 42/W 12/W 55/W 44/W 32/W BHK 073 050/060 042/054 034/054 035/052 034/054 031/057 1/N 39/T 72/W 12/W 44/W 33/W 22/W SHR 075 048/054 037/053 035/054 038/050 035/051 032/058 2/T 45/W 43/W 34/W 55/W 54/W 33/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1046 AM CDT TUE MAY 5 2015 .UPDATE... SHOWERS/STORMS CONTINUE TO MOVE ACROSS WESTERN PORTIONS OF THE FA. THIS ACTIVITY WILL SLOWLY SHIFT E AND NE IN THE AREA... MAYBE REACHING PARTS OF THE I-35 CORRIDOR BY LATE AFTN. HAVE ADJUSTED POPS/WX TO SHOW CURRENT TRENDS AND STRETCH HIGHER CHANCE AND LIKELY POPS JUST A LITTLE FURTHER EAST. CLOUDS ARE EXPECTED TO STAY PUT/INCREASE ACROSS THE AREA. THIS CLOUD COVER ALONG WITH THE RAIN WILL SLOW THE WARM UP ACROSS AT LEAST THE WESTERN HALF OF THE AREA... ESPECIALLY IN WESTERN OK AND WESTERN NORTH TEXAS. UPDATES OUT SOON. && .PREV DISCUSSION... /ISSUED 624 AM CDT TUE MAY 5 2015/ AVIATION...05/12Z TAF ISSUANCE... ACTIVE AVIATION FORECAST PERIOD. RA WILL CONTINUE TO SLOWLY SPREAD INTO WRN OK THROUGH THE MORNING HOURS. RA AND TSRA WILL INCREASE THROUGH THE AFTN AND SPREAD EASTWARD INTO CENTRAL OKLAHOMA INTO THE EVENING. TRIED TO KEEP TAFS SIMPLE... WITH PREVAILING RA OR TSRA WHEN NECESSARY. HEAVY SHOWERS AND THUNDERSTORMS MAY RESULT IN BRIEF PERIODS OF MVFR TO POTENTIALLY IFR VIS THROUGH THE DAY. AS CLOUD COVER INCREASES THROUGH THE AFTN AND EVENING... MVFR CEILINGS WILL SLOWLY DROP TO IFR AT SOME SITES OVERNIGHT. WINDS WILL REMAIN OUT OF THE S/SE THROUGH THE PERIOD... GUSTY THROUGH THE MORNING AND AFTERNOON... BETWEEN 20 TO 25KTS. JTK PREV DISCUSSION... /ISSUED 340 AM CDT TUE MAY 5 2015/ DISCUSSION... PRIMARY FORECAST CONCERN THIS MORNING IS FOCUSED ON TODAY THROUGH WEDNESDAY THUNDERSTORM CHANCES. HOWEVER... THUNDERSTORM CHANCES WILL CONTINUE NEAR DAILY THROUGH THE WEEKEND. CURRENTLY... CONVECTION ACROSS WEST TEXAS... ALONG AND EAST OF THE LLANO ESTACADO... CONTINUES... WITH THE SFC LOW SLOWLY EVOLVING ACROSS THE BIG BEND OF TEXAS. THROUGH MIDNIGHT... NEARLY 4 TO 5 INCHES OF RAIN HAD FALLEN ACROSS PORTIONS OF WEST TEXAS. EXPECT THE SFC LOW TO SLOWLY LIFT N/NE ACROSS FAR WEST TEXAS... WITH SHOWERS AND THUNDERSTORMS CONTINUING TO MOVE NWRD ACROSS THE W TX AND THE PANHANDLES INTO WRN N TX AND FAR WRN OK THROUGH SUNRISE. MESOSCALE GUIDANCE IS IN GOOD AGREEMENT... ALTHOUGH THE HRRR MIGHT BE A TAD BULLISH WITH THE EWRD EXTENT OF PRECIP INTO OK THROUGH MID MORNING. SHOWERS AND THUNDERSTORMS CHANCES WILL SLOWLY INCREASE ACROSS WRN OK AND WRN N TX THROUGH THE AFTN. LOCALLY HEAVY RAINFALL MAY BE AN ISSUE LATER THIS MORNING/THIS AFTN AS BANDING MAY DEVELOP ALONG THE ERN PANHANDLES/WRN OK... WHERE THE BETTER ISENTROPIC RESPONSE MAY SET UP ON THE ERN PERIPHERY OF THE H500 LOW. WITH GOOD MID-LEVEL ASCENT AND A NARROW BAND OF MUCAPE VALUES OF 600 TO 900 J/KG... WOULD NOT BE SURPRISED TO SEE SOME LOCALLY HIGHER RAINFALL GREATER THAN 1 INCH THROUGH THE DAY. THE NAM IS THE MOST AGGRESSIVE WITH QPF... SO IT WILL BE INTERESTING TO SEE HOW TODAY UNFOLDS. AS FOR STRONG TO SEVERE STORMS TODAY... THE BEST CHANCE WILL BE LATE THIS AFTN/EVENING ACROSS FAR W/SWRN OK AND WRN N TX. OF COURSE... ANY STORM DEVELOPMENT WILL BE HIGHLY DEPENDENT ON WHAT HAPPENS THIS MORNING AND AFTN. THERE IS SOME CONCERN CLOUD COVER WILL PERSIST THROUGH THE AFTN HOURS... LIMITING HEATING/INSTABILITY DEVELOPMENT. FORCING WILL BE AVAILABLE FROM A WEAK DRYLINE AND BROAD SCALE ASCENT... AS WELL AS ANY LEFT OVER BOUNDARIES FROM EARLIER CONVECTION. ALTHOUGH INSTABILITY WILL BE PRIMARY QUESTION THIS AFTN... THERE WILL BE QUITE A BIT OF SHEAR AVAILABLE... 40 TO 55KTS 0-6KM AND IF WE CAN RECOVER... A WINDOW AROUND 21-03Z FOR SOME 1000- 1400 J/KG SKINNY CAPE PROFILES. MUCH OF THE INSTABILITY WILL BE ELEVATED... AND GIVEN BUFR PROFILES... LARGE HAIL... UP TO GOLF BALLS... AND SEVERE WINDS WOULD BE THE PRIMARY HAZARDS... WITH THE TORNADO HAZARD LOW. FOR WEDNESDAY... CLUSTERS OR A COMPLEX OF THUNDERSTORMS WILL LIKELY BE ONGOING AND LIFTING EWRD ACROSS CENTRAL OK THROUGH SUNRISE. THIS ACTIVITY WILL SLOWLY DIMINISH AND EXIT EWRD THROUGH THE DAY AS THE H500 SHORT WAVE FINALLY EJECTS NWRD INTO THE NRN HIGH PLAINS. ONCE AGAIN... HOW THIS ACTIVITY EVOLVES THROUGH THE MORNING WILL PLAY THE LEAD ROLE IN OUR SEVERE WEATHER CHANCES WED AFTN/EVENING. AT THE MOMENT... IF WE CAN GET CLEARING ACROSS WRN OK IN THE VICINITY OF THE DRYLINE... MODEST MLCAPE VALUES CAN BE ANTICIPATED... 1000-1500 J/KG. THIS PAIRED WITH GOOD SHEAR ONCE AGAIN... STORMS ON THE DRYLINE WILL LIKELY DEVELOP RAPIDLY AND BE GOOD HAIL PRODUCERS... UP TO TENNIS BALL SIZED... AS WELL AS PRODUCING POTENTIALLY DAMAGING WIND GUSTS. AS FOR TORNADOES... CHANCES LOOK BETTER IN KS... WHERE SHEAR/LL WINDS WILL BE ENHANCED BY THE MORE FAVORABLE POSITION OF THE SFC LOW OVER ERN CO/WRN KS. GUIDANCE SUGGESTS OK AND NRN TX STORMS WILL MOVE OFF THE DRYLINE... BECOMING ELEVATED QUICKLY AFTER SUNSET. THE CHANCE FOR SEVERE STORMS WILL DIMINISH OVERNIGHT... WITH SCATTERED THUNDERSTORMS PERSISTING THROUGH THU MORNING. FOR THURSDAY INTO FRIDAY... PRECIPITATION CHANCES WILL CONTINUE... ESPECIALLY THU NIGHT INTO FRI... AS A DIFFUSE FRONTAL BOUNDARY STALLS/LINGERS NEAR THE OK/KS BORDER... EXTENDING FROM THE PANHANDLE INTO ERN KS. H500 FLOW REMAINS FAIRLY STATIC AS THE SRN PLAINS REMAINS SANDWICHED BETWEEN A DEEPENING TROUGH IN THE WEST AND A SHARP POSITIVE RIDGE INTO THE MID-ATLANTIC COAST. WITH THIS FLOW REGIME AND THE LINGERING WEAK FRONTAL BOUNDARY... COUPLED WITH CONTINUOUS MOISTURE ADVECTION FROM THE GULF... PERSISTENT AND POSSIBLY EXCESSIVE RAINFALL LIKELY... ESPECIALLY FRI INTO SAT AM. THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE WEEKEND AS THE H500 TROUGH FINALLY LIFTS E/NE ACROSS THE CENTRAL ROCKIES. WITH THIS... THE DRY LINE WILL MAKE ANOTHER PUSH ON SATURDAY... WITH STRONG TO SEVERE STORMS POSSIBLE ONCE AGAIN. DETAILS REMAIN HAZY GIVEN WHATS POSSIBLE TO TRANSPIRE BETWEEN NOW AN THEN. AS WITH TODAY AND WED... THUNDERSTORMS SAT WILL BE DEPENDENT ON HOW THE ATMOSPHERE RECOVERS FROM THE MORNING CONVECTION. PRECIP CHANCES WILL DIMINISH MON INTO TUES. JTK && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 75 63 78 65 / 60 70 40 50 HOBART OK 67 63 80 63 / 80 80 40 50 WICHITA FALLS TX 68 65 82 66 / 90 70 30 50 GAGE OK 67 60 82 62 / 70 80 20 20 PONCA CITY OK 78 65 78 66 / 30 80 50 40 DURANT OK 78 65 78 66 / 50 70 50 40 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/03
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
624 AM CDT TUE MAY 5 2015 .AVIATION...05/12Z TAF ISSUANCE... ACTIVE AVIATION FORECAST PERIOD. RA WILL CONTINUE TO SLOWLY SPREAD INTO WRN OK THROUGH THE MORNING HOURS. RA AND TSRA WILL INCREASE THROUGH THE AFTN AND SPREAD EASTWARD INTO CENTRAL OKLAHOMA INTO THE EVENING. TRIED TO KEEP TAFS SIMPLE... WITH PREVAILING RA OR TSRA WHEN NECESSARY. HEAVY SHOWERS AND THUNDERSTORMS MAY RESULT IN BRIEF PERIODS OF MVFR TO POTENTIALLY IFR VIS THROUGH THE DAY. AS CLOUD COVER INCREASES THROUGH THE AFTN AND EVENING... MVFR CEILINGS WILL SLOWLY DROP TO IFR AT SOME SITES OVERNIGHT. WINDS WILL REMAIN OUT OF THE S/SE THROUGH THE PERIOD... GUSTY THROUGH THE MORNING AND AFTERNOON... BETWEEN 20 TO 25KTS. JTK && .PREV DISCUSSION... /ISSUED 340 AM CDT TUE MAY 5 2015/ DISCUSSION... PRIMARY FORECAST CONCERN THIS MORNING IS FOCUSED ON TODAY THROUGH WEDNESDAY THUNDERSTORM CHANCES. HOWEVER... THUNDERSTORM CHANCES WILL CONTINUE NEAR DAILY THROUGH THE WEEKEND. CURRENTLY... CONVECTION ACROSS WEST TEXAS... ALONG AND EAST OF THE LLANO ESTACADO... CONTINUES... WITH THE SFC LOW SLOWLY EVOLVING ACROSS THE BIG BEND OF TEXAS. THROUGH MIDNIGHT... NEARLY 4 TO 5 INCHES OF RAIN HAD FALLEN ACROSS PORTIONS OF WEST TEXAS. EXPECT THE SFC LOW TO SLOWLY LIFT N/NE ACROSS FAR WEST TEXAS... WITH SHOWERS AND THUNDERSTORMS CONTINUING TO MOVE NWRD ACROSS THE W TX AND THE PANHANDLES INTO WRN N TX AND FAR WRN OK THROUGH SUNRISE. MESOSCALE GUIDANCE IS IN GOOD AGREEMENT... ALTHOUGH THE HRRR MIGHT BE A TAD BULLISH WITH THE EWRD EXTENT OF PRECIP INTO OK THROUGH MID MORNING. SHOWERS AND THUNDERSTORMS CHANCES WILL SLOWLY INCREASE ACROSS WRN OK AND WRN N TX THROUGH THE AFTN. LOCALLY HEAVY RAINFALL MAY BE AN ISSUE LATER THIS MORNING/THIS AFTN AS BANDING MAY DEVELOP ALONG THE ERN PANHANDLES/WRN OK... WHERE THE BETTER ISENTROPIC RESPONSE MAY SET UP ON THE ERN PERIPHERY OF THE H500 LOW. WITH GOOD MID-LEVEL ASCENT AND A NARROW BAND OF MUCAPE VALUES OF 600 TO 900 J/KG... WOULD NOT BE SURPRISED TO SEE SOME LOCALLY HIGHER RAINFALL GREATER THAN 1 INCH THROUGH THE DAY. THE NAM IS THE MOST AGGRESSIVE WITH QPF... SO IT WILL BE INTERESTING TO SEE HOW TODAY UNFOLDS. AS FOR STRONG TO SEVERE STORMS TODAY... THE BEST CHANCE WILL BE LATE THIS AFTN/EVENING ACROSS FAR W/SWRN OK AND WRN N TX. OF COURSE... ANY STORM DEVELOPMENT WILL BE HIGHLY DEPENDENT ON WHAT HAPPENS THIS MORNING AND AFTN. THERE IS SOME CONCERN CLOUD COVER WILL PERSIST THROUGH THE AFTN HOURS... LIMITING HEATING/INSTABILITY DEVELOPMENT. FORCING WILL BE AVAILABLE FROM A WEAK DRYLINE AND BROAD SCALE ASCENT... AS WELL AS ANY LEFT OVER BOUNDARIES FROM EARLIER CONVECTION. ALTHOUGH INSTABILITY WILL BE PRIMARY QUESTION THIS AFTN... THERE WILL BE QUITE A BIT OF SHEAR AVAILABLE... 40 TO 55KTS 0-6KM AND IF WE CAN RECOVER... A WINDOW AROUND 21-03Z FOR SOME 1000- 1400 J/KG SKINNY CAPE PROFILES. MUCH OF THE INSTABILITY WILL BE ELEVATED... AND GIVEN BUFR PROFILES... LARGE HAIL... UP TO GOLF BALLS... AND SEVERE WINDS WOULD BE THE PRIMARY HAZARDS... WITH THE TORNADO HAZARD LOW. FOR WEDNESDAY... CLUSTERS OR A COMPLEX OF THUNDERSTORMS WILL LIKELY BE ONGOING AND LIFTING EWRD ACROSS CENTRAL OK THROUGH SUNRISE. THIS ACTIVITY WILL SLOWLY DIMINISH AND EXIT EWRD THROUGH THE DAY AS THE H500 SHORT WAVE FINALLY EJECTS NWRD INTO THE NRN HIGH PLAINS. ONCE AGAIN... HOW THIS ACTIVITY EVOLVES THROUGH THE MORNING WILL PLAY THE LEAD ROLE IN OUR SEVERE WEATHER CHANCES WED AFTN/EVENING. AT THE MOMENT... IF WE CAN GET CLEARING ACROSS WRN OK IN THE VICINITY OF THE DRYLINE... MODEST MLCAPE VALUES CAN BE ANTICIPATED... 1000-1500 J/KG. THIS PAIRED WITH GOOD SHEAR ONCE AGAIN... STORMS ON THE DRYLINE WILL LIKELY DEVELOP RAPIDLY AND BE GOOD HAIL PRODUCERS... UP TO TENNIS BALL SIZED... AS WELL AS PRODUCING POTENTIALLY DAMAGING WIND GUSTS. AS FOR TORNADOES... CHANCES LOOK BETTER IN KS... WHERE SHEAR/LL WINDS WILL BE ENHANCED BY THE MORE FAVORABLE POSITION OF THE SFC LOW OVER ERN CO/WRN KS. GUIDANCE SUGGESTS OK AND NRN TX STORMS WILL MOVE OFF THE DRYLINE... BECOMING ELEVATED QUICKLY AFTER SUNSET. THE CHANCE FOR SEVERE STORMS WILL DIMINISH OVERNIGHT... WITH SCATTERED THUNDERSTORMS PERSISTING THROUGH THU MORNING. FOR THURSDAY INTO FRIDAY... PRECIPITATION CHANCES WILL CONTINUE... ESPECIALLY THU NIGHT INTO FRI... AS A DIFFUSE FRONTAL BOUNDARY STALLS/LINGERS NEAR THE OK/KS BORDER... EXTENDING FROM THE PANHANDLE INTO ERN KS. H500 FLOW REMAINS FAIRLY STATIC AS THE SRN PLAINS REMAINS SANDWICHED BETWEEN A DEEPENING TROUGH IN THE WEST AND A SHARP POSITIVE RIDGE INTO THE MID-ATLANTIC COAST. WITH THIS FLOW REGIME AND THE LINGERING WEAK FRONTAL BOUNDARY... COUPLED WITH CONTINUOUS MOISTURE ADVECTION FROM THE GULF... PERSISTENT AND POSSIBLY EXCESSIVE RAINFALL LIKELY... ESPECIALLY FRI INTO SAT AM. THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE WEEKEND AS THE H500 TROUGH FINALLY LIFTS E/NE ACROSS THE CENTRAL ROCKIES. WITH THIS... THE DRY LINE WILL MAKE ANOTHER PUSH ON SATURDAY... WITH STRONG TO SEVERE STORMS POSSIBLE ONCE AGAIN. DETAILS REMAIN HAZY GIVEN WHATS POSSIBLE TO TRANSPIRE BETWEEN NOW AN THEN. AS WITH TODAY AND WED... THUNDERSTORMS SAT WILL BE DEPENDENT ON HOW THE ATMOSPHERE RECOVERS FROM THE MORNING CONVECTION. PRECIP CHANCES WILL DIMINISH MON INTO TUES. JTK && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 77 63 78 65 / 40 70 40 50 HOBART OK 72 63 80 63 / 70 80 40 50 WICHITA FALLS TX 76 65 82 66 / 60 70 30 50 GAGE OK 69 60 82 62 / 70 80 20 20 PONCA CITY OK 79 65 78 66 / 10 80 50 40 DURANT OK 78 65 78 66 / 60 70 50 40 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
629 AM CDT TUE MAY 5 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...MVFR CIGS DID NOT MATERIALIZE AT BRO AND HRL WITH THOSE CIGS AFFECTING MFE ATTM. GUSTY WINDS TO BEGIN AROUND 14Z AT WHICH TIME THOSE CIGS SHOULD BEGIN TO SCATTER TO VFR BY LATE MORNING. GUSTS TO 30 KNOTS APPEAR POSSIBLE ESPECIALLY AT MFE WHERE STRONGER LOW LEVEL WINDS RESIDE. WINDS WILL DECREASE AFTER SUNSET BUT GUSTS WILL CONTINUE TILL AROUND MIDNIGHT. MVFR CIGS WILL BUILD BACK IN AFTER SUNSET WHICH WILL CONTINUE THROUGH THE REST OF THE TAF PERIOD. && .PREV DISCUSSION... /ISSUED 416 AM CDT TUE MAY 5 2015/ SHORT TERM /NOW THROUGH WEDNESDAY/...UPPER TROF ACROSS THE FOUR CORNERS REGION WILL OPEN UP AND WEAKEN AS IT HEADS NORTHEASTWARD INTO COLORADO THEN BECOME ABSORBED IN THE DEEPENING LARGER SCALE TROUGH ACROSS THE WESTERN CONUS. DIFFLUENCE REMAINS ACROSS THE AREA BUT BETTER DYNAMICS ASSOCIATED WITH THE UPPER TROF WILL REMAIN WELL REMOVED FROM THE AREA. 700MB FLOW STRENGTHENS AND REINFORCES MID LEVEL CAPPING WITH DRY AIR ADVECTING FROM THE MEXICAN PLATEAU AND OVER SPREADING THE AREA. LEFT SLIGHT CHANCE POPS THIS MORNING FOR FAR WESTERN SECTIONS BUT BELIEVE CAP WILL KEEP THE LID ON MOST IF NOT ALL PRECIPITATION TODAY. HRRR AND NAM12 SUPPORT THIS IDEA. BREEZY CONDITIONS CONTINUE TODAY WITH DEEPENING LOW PRESSURE ACROSS WEST TEXAS WITH GUSTS APPROACHING 30 MPH. THERE ARE INDICATIONS IN THE MODELS OF THUNDERSTORMS DEVELOPING ON THE HIGHER TERRAIN THIS EVENING AND MOVE EASTWARD TOWARDS OUR AREA BUT DRY AIR SHOULD WEAKEN THEM BEFORE MAKING ACROSS THE RIVER. THEREFORE WILL KEEP FORECAST DRY TONIGHT. BREEZY CONDITIONS CONTINUE WEDNESDAY WITH ANOTHER ROUND OF 700MB DRY AIR ADVECTING FROM THE WEST. CONDITIONS WILL BE FAIRLY SIMILIAR TO THE PAST SEVERAL DAYS. HIGHS IN THE 80S THE NEXT SEVERAL DAYS AND PERHAPS REACHING 90 DEGREES IN THE FAR NORTHWESTERN SECTIONS OF ZAPATA COUNTY. LOWS WILL BE IN THE 70S. LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...AS LOW PRESSURE TROUGHS DEEPEN ACROSS SW U.S. AND JUST OFF THE SE U.S. COAST MID TO UPPER LEVEL RIDGE BUILDS OVER SOUTH TEXAS AND THE WESTERN GULF. THIS SHOULD IN A MOSTLY DRY RAINFREE WED NIGHT THROUGH SUNDAY PERIOD. NOT UNTIL THE WESTERN TROUGH BEGINS TO MOVE NORTHEAST LATE NEXT WEEKEND INTO EARLY NEXT WEEK WILL THERE BE SOME INCREASE IN THE CHANCE OF RAIN. MODELS REMAIN RATHER PERSISTENT IN THIS PATTERN AND HAVE BEEN IN GOOD CONSISTENCY MAKING FOR A BETTER THAN AVERAGE CONFIDENCE IN THE OUTGOING FORECAST. OVERALL, THE EARLY DOG DAYS OF SUMMER WILL BE SETTING UP AS THE BUILDING UPPER RIDGE AND STRONG CAPPING INVERSION BETWEEN 850-700MB TO DOMINATE. THE BUILDING RIDGE PROMOTES A DIVERGENT Q VECTOR FIELD OR A CONFLUENT FLOW ALOFT AND THE 850-700MB CAPPING INVERSION STRENGTHENS WITH A THE PERSISTENT SOUTHWEST FLOW. WITHOUT ANY LIFTING MECHANISM AND DISTURBANCES/VORT MAXES LIKELY TO BE DIVERTED NORTHEAST OF THE AREA DO NOT SEE ANY SIGNIFICANT CHANCE OF RAIN. WITH THAT SAID HAVE KEPT THE LOW CHANCE POPS ACROSS THE NW ZONES JUST IN CASE A ROUGE THUNDERSTORM MOVES IN FROM THE SIERRA MADRE. WARM/HOT, HUMID AND BREEZY WILL BE THE WORD THROUGH AT LEAST SUNDAY WITH WINDIEST DAYS NEXT WEEKEND AS THE UPPER TROUGH OVER THE DESERT SW LIFTS INTO THE CENTRAL PLAINS STRENGTHENING THE PRESSURE GRADIENT. AS WE MOVE INTO NEXT WEEK MODELS SUGGEST AN INCREASE IN RAIN CHANCES. THE WEAKENING OF THE RIDGE AND A TRAILING COLD FRONT MOVING INTO CENTRAL TEXAS ALONG WITH POOLING MOISTURE SOUTH OF THE BOUNDARY LOOKS TO THE INGREDIENTS NEEDED TO GET A FEW STORMS IN OUR REGION. HAVE BROAD BRUSHED THE CWA WITH LOW GRADE POPS NEXT MONDAY AND TUESDAY TO ACCOMMODATE THE MODEL CONSENSUS. MARINE...NOW THROUGH WEDNESDAY...MODERATE SOUTHEAST WINDS AND MODERATE SEAS WILL CONTINUE AS HIGH PRES REMAINS DOMINANT OVER THE SOUTHEAST U.S. AND THE NORTH GULF...COUNTERBALANCED BY SOMEWHAT LOWER PRESSURE OVER THE SOUTHERN HIGH PLAINS. WINDS AND SEAS MAY INCREASE SLIGHTLY AT TIMES...WITH SMALL CRAFT EXERCISE CAUTION TO LOW END SMALL CRAFT ADVISORY CONDITIONS POSSIBLE. WEDNESDAY NIGHT THROUGH SUNDAY...A MODERATE TO STRONG PRESSURE GRADIENT TO PERSIST THIS PERIOD. BROAD HIGH PRESSURE OVER THE GULF TO INTERACT WITH LOWER PRESSURE OVER NW TEXAS TO PRODUCE MARGINAL SMALL CRAFT ADVISORY CONDITIONS WEDNESDAY NIGHT THROUGH FRIDAY. LOW PRESSURE STRENGTHEN OVER THE WEEKEND WITH A POSSIBLE UPTICK IN WINDS AND SEAS. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 55
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
604 AM CDT TUE MAY 5 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 232 AM CDT TUE MAY 5 2015 MAIN FOCUS IS ON RAIN CHANCES AND RESULTANT TEMPERATURES. WEAK SHORT WAVE TROUGH ENHANCED BY WHAT APPEARS TO BE AN EMBEDDED MESOSCALE CONVECTIVE VORTICITY WAS SPINNING THROUGH IA OVERNIGHT RESULTING IN WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS. THUS FAR THE RAIN HAS BEEN CONFINED TO IA/IL AND EXTREME SOUTHERN WI. VARIOUS SHORT TERM MODELS SUGGEST SOME OF THE FRONTOGENETIC FORCING WILL TRY AND SET UP FURTHER NORTH NEAR THE I-90 CORRIDOR BUT THUS FAR NOTHING HAS BEEN DEVELOPING. NORTHWARD DEVELOPMENT MAY BE HAMPERED BY ENTRAINMENT OF DRY AIR ON EAST/NORTHEAST WINDS WHERE LOW LEVEL DEWPOINTS ARE IN THE 30S. OTHERWISE ANTICIPATE THAT THE RAIN AREA WILL SHIFT EAST AND ANY LINGERING RAIN CHANCE WILL REALLY DIMINISH AS THE DAY WEARS ON. WILL MAINTAIN A SLIGHT CHANCE OVER THE SOUTH WHERE BETTER MOISTURE AND RESIDUAL BOUNDARIES MAY WORK WITH DAYTIME HEATING TO GENERATE SOME SHOWERS LATER TODAY. ATTENTION THEN SHIFTS TO CONVECTIVE POTENTIAL TONIGHT AS THE FRONTAL BOUNDARY ACROSS IA MOVES BACK NORTH. TREND HAS BEEN FOR LESS AND LESS ACTION ALONG THE NORTHWARD MOVING AND WEAKENING WARM FRONT. STILL...MAINTAINED RAIN RISK LATE TONIGHT INTO EARLY WEDNESDAY AS MOISTURE CONVERGENCE AND WEAK FRONTOGENETIC SIGNAL TRANSLATE THROUGH. CLOUDS AND RAIN SHOULD KEEP TEMPERATURES SOMEWHAT IN CHECK. THIS ALREADY ACCOUNTED FOR IN PREVIOUS FORECAST SO MINIMAL CHANGES. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 232 AM CDT TUE MAY 5 2015 ACTIVE WEATHER PATTERN ON TAP WITH SEVERAL DISTURBANCES MOVING THROUGH THE REGION OUT OF THE MEAN LONG WAVE TROUGH OVER THE WESTERN CONUS. CHALLENGE FOR THE LONGER TERM IS TRYING TO IDENTIFY THE BEST CHANCE FOR NO RAIN AND HOW TO DEPICT THAT IN THE FORECAST. SIGNIFICANT SHORT WAVE TROUGH EJECTS NORTHEAST ACROSS THE PLAINS AND INTO THE DAKOTAS BY THURSDAY...INDUCING A SURFACE LOW AND TRACKING IT INTO WESTERN ONTARIO BY THURSDAY NIGHT. BEST RAIN CHANCES WILL REMAIN WEST OF THE GENERAL FORECAST AREA...BUT THERE IS A SUGGESTION BY SEVERAL OF THE MEDIUM RANGE MODELS THAT SOME ACTIVITY COULD DEVELOP IN THE WARM/MOIST ADVECTION REGIME OUT AHEAD OF THE SYSTEM. SO AM FORCED TO KEEP SOME CHANCES IN THE FORECAST. COLD FRONT TRAILING THIS SYSTEM WILL EDGE THROUGH THE FORECAST AREA ON FRIDAY AND MAY LINGER AROUND THE AREA INTO SATURDAY. MODELS SOMEWHAT AT ODDS AS TO HOW FAR SOUTH IT WILL PUSH...WITH THE GFS MOST AGGRESSIVE WITH THE COOLER AND DRIER AIR. IF THIS SCENARIO PANS OUT...SATURDAY COULD BE QUITE PLEASANT AND DRY. ECMWF LESS OPTIMISTIC WITH THE BOUNDARY NEARBY. MESSY PATTERN THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK AS THE CLOSED CIRCULATION IN THE BASE OF THE LONG WAVE TROUGH FINALLY EJECTS NORTHEAST THROUGH THE UPPER MIDWEST. MODELS DIFFER IN THE DETAILS...AND THERE ARE NOW INDICATIONS THAT THIS GENERAL CIRCULATION WILL LINGER AROUND THE REGION THROUGH NEARLY ALL OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 604 AM CDT TUE MAY 5 2015 BAND OF SHOWERS NORTH OF THE STATIONARY FRONT CONTINUE TO WORK SLOWLY NORTH THIS MORNING...BUT THE 05.09Z HRRR SUGGESTS THEY SHOULD NOT GET MUCH FARTHER NORTH. AS A RESULT...WILL STAY WITH VCSH AT BOTH TAF SITES FOR NOW BUT WILL MONITOR KLSE CLOSELY FOR AN UPDATE TO INCLUDE A SHORT PERIOD OF SOME RAIN. MVFR CEILINGS AHEAD OF THESE SHOWERS ARE ALREADY IMPACTING BOTH TAF SITES AND WILL INCLUDE THESE INTO THE EARLY AFTERNOON. AFTER THAT...THE 05.06Z NAM WOULD SUGGEST BOTH TAF SITES WOULD BE STUCK IN THE MVFR CEILINGS ALL DAY WHILE THE 05.09Z RAP FOR THE MOST PART KEEPS VFR. LOOKING DOWNSTREAM INTO IOWA...THERE IS A BACK EDGE TO THE MVFR CLOUDS SO WILL GO WITH THE RAP FOR THE REMAINDER OF THE DAY WITH VFR CONDITIONS. THE FRONT SHOULD THEN START TO LIFT NORTH TOWARD THE AREA LATE TONIGHT. THE FORCING WITH THE FRONT LOOKS TO BE RATHER WEAK AND WHILE THERE COULD BE SOME SHOWERS AROUND AFTER 06.06Z...NOT CONFIDENT ENOUGH IN THESE OCCURRING TO EVEN INCLUDE A VCSH AT THIS TIME. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...MW LONG TERM...MW AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
934 AM MDT TUE MAY 5 2015 .UPDATE...VISIBLE SATELLITE IMAGERY AND WYDOT WEBCAMS CONTINUE TO SHOW AREAS OF DENSE FOG AROUND CHEYENNE TO THE SUMMIT EAST OF LARAMIE...AND BETWEEN SINCLAIR AND RAWLINS WY. WE UPDATED TO INCLUDE THE RAWLINS AREA ALONG I-80 IN THE DENSE FOG ADVISORY AND TO EXTEND THE ADVISORY UNTIL NOON MDT. EXPECT THE FOG WILL START TO LIFT BY EARLY AFTERNOON. OTHERWISE...NO FURTHER CHANGES NEEDED IN THE NEAR TERM FORECAST. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 WEBCAMS ALONG INTERSTATE 80 HAVE CONSISTENTLY SHOWN DENSE FOG FROM THE SUMMIT TO CHEYENNE OVER THE PAST FEW HOURS. DECIDED TO ADD CENTRAL LARAMIE COUNTY (CHEYENNE) TO THE DENSE FOG ADVISORY THRU 16Z WITH THE CYS OBS DROPPING TO ONE QUARTER MILE. THE LOW CLOUDS AND FOG WILL REMAIN QUITE PERSISTENT THROUGH THE MORNING WITH THE HRRR MODEL INDICATING LIFR/IFR CONDITIONS THROUGH 18Z FROM THE INTERSTATE 80 SUMMIT EASTWARD TO CHEYENNE COUNTY. THIS MAKES SENSE AS THE OVERALL SFC PATTERN OF VERY MOIST SOUTH TO SOUTHEAST WINDS WILL CONTINUE THROUGH THE MORNING. WATER VAPOR IMAGERY SHOWS THE SUBTROPICAL UPPER LOW SPINNING OVER NORTHEAST ARIZONA. THE MODELS MOVE THIS FEATURE TO THE NORTHEAST OVER THE COURSE OF THE DAY TO NEAR NORTHERN COLORADO BY THIS EVENING. ONLY AN ISOLATED TO SCATTERED COVERAGE OF SHOWERS IS EXPECTED THROUGH THE EARLY AFTN ALONG THE COLORADO BORDER. HOWEVER...MIDLVL HEIGHT FALLS WILL COMBINE WITH INCREASING DEEP LAYER MOISTURE TO PROMOTE A MORE WIDESPREAD COVERAGE BY THE LATE AFTN AND EARLY EVENING. MOISTURE IS PLENTIFUL WITH THIS SYSTEM...IN FACT PW VALUES OF 0.75-1.0 INCHES OVER THE PLAINS ARE 2 STANDARD DEVIATIONS ABOVE NORMAL FOR EARLY MAY. THUS...WITH RELATIVELY SLOW STORM MOTIONS...LOCALLY HEAVY RAIN WILL BE A CONCERN ESPECIALLY OVER THE NEBRASKA PANHANDLE. WHILE ISOLATED TSTMS WILL BE POSSIBLE THIS AFTN...THE VERY WEAK INSTABILITY AND SHEAR WILL MAKE STRONG STORMS UNLIKELY. SPC HAS DROPPED THE MARGINAL THREAT OVER THE SOUTHERN PANHANDLE. WITH THE MIDLVL DISTURBANCE OVERHEAD TONIGHT...WILL KEEP A CHANCE OF SHOWERS GOING. SOUTHEAST SFC WINDS ARE IN PLACE THRU 12Z WED...SO FOG WILL AGAIN BE A THREAT OVER PORTIONS OF THE AREA. THE SHORTWAVE WILL PUSH INTO WESTERN SOUTH DAKOTA/NEBRASKA BY WED AFTN. THE MODELS SHOW THE HIGHEST QPF OVER THE PLAINS OF SOUTHEAST WY AS A SFC COLD FRONT INTERACTS WITH GOOD MOISTURE. WILL HAVE ISOLATED TSTMS DURING THE AFTN WITH SOME LIMITED CAPE. PRECIP CHANCES DROP OFF WED EVENING BEHIND THE FRONT AS A DRIER AIRMASS MOVES IN. THERE COULD ACTUALLY BE A 18-24 HR PERIOD FROM WED EVENING THRU THURS AFTN WHEN MUCH OF THE CWA WILL BE PRECIP FREE. SCATTERED STORMS WILL ONCE AGAIN DEVELOP ALONG AND WEST OF THE LARAMIE RANGE BY THURS AFTN...WITH LIMITED COVERAGE OVER THE PLAINS IN A MORE STABLE AIRMASS. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 UNSETTLED WEATHER CONTINUES IN THE LONG TERM. MEDIUM RANGE GUIDANCE CONTINUES TO ADVERTISE THE POSSIBILITY OF WINTER WEATHER RETURNING TO THE AREA LATE IN THE WEEKEND. STARTING OFF THURSDAY NIGHT...WE STILL HAVE THE STALLED SURFACE BOUNDARY LAYING ALONG THE LARAMIE RANGE...OR SLIGHTLY WEST. BOTH THE GFS AND ECMWF VERY SIMILAR BRINGING ANOTHER PIECE OF ENERGY NORTHEAST FROM THE DESERT SOUTHWEST TO INTERACT WITH THIS BOUNDARY...SO WILL KEEP CHANCE POPS GOING FOR THE THURSDAY NIGHT TIME FRAME. PROBABLY PRETTY LIGHT SHOWERS THOUGH AS HAS BEEN THE CASE THE PAST FEW NIGHTS. CONVECTION PICKS UP THROUGH FRIDAY AFTERNOON WITH BOTH MODELS CONCENTRATING ON THE SOUTHERN PANHANDLE AND NORTHEASTERN COLORADO. SOUTHEAST UPSLOPING WINDS TO CONTINUE. GFS AND ECMWF CONTINUE TO AGREE ON A CLOSED LOW ROUNDING THE BASE OF THE LONGWAVE TROUGH SATURDAY MORNING AND BEGINNING TO LIFT NORTHEAST INTO SOUTHWESTERN COLORADO SATURDAY AFTERNOON. OUR FORECAST AREA IS SQUARE IN THE WRAP AROUND MOISTURE TO THE NORTH OF THIS LOW. ECMWF A LITTLE FASTER ON MOVEMENT OVER THE GFS...MOVING THE LOW INTO CENTRAL NEBRASKA ROUGHLY 12 HOURS FASTER THAN THE GFS. BOTH ARE COLD THOUGH ON 700MB TEMPERATURES AND COLD ENOUGH FOR WIDESPREAD SNOW. BOTH ARE SHOWING 850MB WINDS OF 40 TO 45KTS ACROSS THE PANHANDLE AND EASTERN WYOMING. WINTER IS NOT DONE WITH SOUTHEAST WYOMING AND WE NEED TO BE WATCHING THE EVOLUTION OF THIS EVENT AS HEAVY SNOW AND WINTER HEADLINES ARE DEFINITELY A POSSIBILITY FOR PORTIONS OF THE FORECAST AREA...POSSIBLY EVEN THE PANHANDLE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 536 AM MDT TUE MAY 5 2015 WIDESPREAD IFR/LIFR CEILINGS AND VISIBILITIES TO PERSIST ACROSS MUCH OF THE AREA THROUGH THE MORNING HOURS. SHOWERS BECOME WIDESPREAD ACROSS THE SOUTHERN PANHANDLE AND I-80 CORRIDOR LATE AFTERNOON INTO THE EVENING WITH IFR/LIFR CONDITIONS RETURNING. && .FIRE WEATHER... ISSUED AT 345 AM MDT TUE MAY 5 2015 A COOL AND WET WEATHER PATTERN WILL KEEP FIRE WEATHER CONCERNS VERY LOW THROUGH THE WEEKEND. AFTERNOON AND EVENING SHOWERS WILL BE POSSIBLE TODAY THROUGH THURSDAY...WITH GOOD CHANCES FOR MEASURABLE RAIN. MORE SUBSTANTIAL PRECIPITATION AMOUNTS ARE LOOKING POSSIBLE BY LATE FRIDAY INTO SUNDAY ASSOCIATED WITH A STRONG STORM SYSTEM. MINIMUM RELATIVE HUMIDITY VALUES SHOULD BE WELL ABOVE CRITICAL THRESHOLDS THROUGH THE PERIOD. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...DENSE FOG ADVISORY UNTIL NOON MDT TODAY FOR WYZ104-105-109-110- 116>118. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...GCC AVIATION...GCC FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
538 AM MDT TUE MAY 5 2015 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 WEBCAMS ALONG INTERSTATE 80 HAVE CONSISTENTLY SHOWN DENSE FOG FROM THE SUMMIT TO CHEYENNE OVER THE PAST FEW HOURS. DECIDED TO ADD CENTRAL LARAMIE COUNTY (CHEYENNE) TO THE DENSE FOG ADVISORY THRU 16Z WITH THE CYS OBS DROPPING TO ONE QUARTER MILE. THE LOW CLOUDS AND FOG WILL REMAIN QUITE PERSISTENT THROUGH THE MORNING WITH THE HRRR MODEL INDICATING LIFR/IFR CONDITIONS THROUGH 18Z FROM THE INTERSTATE 80 SUMMIT EASTWARD TO CHEYENNE COUNTY. THIS MAKES SENSE AS THE OVERALL SFC PATTERN OF VERY MOIST SOUTH TO SOUTHEAST WINDS WILL CONTINUE THROUGH THE MORNING. WATER VAPOR IMAGERY SHOWS THE SUBTROPICAL UPPER LOW SPINNING OVER NORTHEAST ARIZONA. THE MODELS MOVE THIS FEATURE TO THE NORTHEAST OVER THE COURSE OF THE DAY TO NEAR NORTHERN COLORADO BY THIS EVENING. ONLY AN ISOLATED TO SCATTERED COVERAGE OF SHOWERS IS EXPECTED THROUGH THE EARLY AFTN ALONG THE COLORADO BORDER. HOWEVER...MIDLVL HEIGHT FALLS WILL COMBINE WITH INCREASING DEEP LAYER MOISTURE TO PROMOTE A MORE WIDESPREAD COVERAGE BY THE LATE AFTN AND EARLY EVENING. MOISTURE IS PLENTIFUL WITH THIS SYSTEM...IN FACT PW VALUES OF 0.75-1.0 INCHES OVER THE PLAINS ARE 2 STANDARD DEVIATIONS ABOVE NORMAL FOR EARLY MAY. THUS...WITH RELATIVELY SLOW STORM MOTIONS...LOCALLY HEAVY RAIN WILL BE A CONCERN ESPECIALLY OVER THE NEBRASKA PANHANDLE. WHILE ISOLATED TSTMS WILL BE POSSIBLE THIS AFTN...THE VERY WEAK INSTABILITY AND SHEAR WILL MAKE STRONG STORMS UNLIKELY. SPC HAS DROPPED THE MARGINAL THREAT OVER THE SOUTHERN PANHANDLE. WITH THE MIDLVL DISTURBANCE OVERHEAD TONIGHT...WILL KEEP A CHANCE OF SHOWERS GOING. SOUTHEAST SFC WINDS ARE IN PLACE THRU 12Z WED...SO FOG WILL AGAIN BE A THREAT OVER PORTIONS OF THE AREA. THE SHORTWAVE WILL PUSH INTO WESTERN SOUTH DAKOTA/NEBRASKA BY WED AFTN. THE MODELS SHOW THE HIGHEST QPF OVER THE PLAINS OF SOUTHEAST WY AS A SFC COLD FRONT INTERACTS WITH GOOD MOISTURE. WILL HAVE ISOLATED TSTMS DURING THE AFTN WITH SOME LIMITED CAPE. PRECIP CHANCES DROP OFF WED EVENING BEHIND THE FRONT AS A DRIER AIRMASS MOVES IN. THERE COULD ACTUALLY BE A 18-24 HR PERIOD FROM WED EVENING THRU THURS AFTN WHEN MUCH OF THE CWA WILL BE PRECIP FREE. SCATTERED STORMS WILL ONCE AGAIN DEVELOP ALONG AND WEST OF THE LARAMIE RANGE BY THURS AFTN...WITH LIMITED COVERAGE OVER THE PLAINS IN A MORE STABLE AIRMASS. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 UNSETTLED WEATHER CONTINUES IN THE LONG TERM. MEDIUM RANGE GUIDANCE CONTINUES TO ADVERTISE THE POSSIBILITY OF WINTER WEATHER RETURNING TO THE AREA LATE IN THE WEEKEND. STARTING OFF THURSDAY NIGHT...WE STILL HAVE THE STALLED SURFACE BOUNDARY LAYING ALONG THE LARAMIE RANGE...OR SLIGHTLY WEST. BOTH THE GFS AND ECMWF VERY SIMILAR BRINGING ANOTHER PIECE OF ENERGY NORTHEAST FROM THE DESERT SOUTHWEST TO INTERACT WITH THIS BOUNDARY...SO WILL KEEP CHANCE POPS GOING FOR THE THURSDAY NIGHT TIME FRAME. PROBABLY PRETTY LIGHT SHOWERS THOUGH AS HAS BEEN THE CASE THE PAST FEW NIGHTS. CONVECTION PICKS UP THROUGH FRIDAY AFTERNOON WITH BOTH MODELS CONCENTRATING ON THE SOUTHERN PANHANDLE AND NORTHEASTERN COLORADO. SOUTHEAST UPSLOPING WINDS TO CONTINUE. GFS AND ECMWF CONTINUE TO AGREE ON A CLOSED LOW ROUNDING THE BASE OF THE LONGWAVE TROUGH SATURDAY MORNING AND BEGINNING TO LIFT NORTHEAST INTO SOUTHWESTERN COLORADO SATURDAY AFTERNOON. OUR FORECAST AREA IS SQUARE IN THE WRAP AROUND MOISTURE TO THE NORTH OF THIS LOW. ECMWF A LITTLE FASTER ON MOVEMENT OVER THE GFS...MOVING THE LOW INTO CENTRAL NEBRASKA ROUGHLY 12 HOURS FASTER THAN THE GFS. BOTH ARE COLD THOUGH ON 700MB TEMPERATURES AND COLD ENOUGH FOR WIDESPREAD SNOW. BOTH ARE SHOWING 850MB WINDS OF 40 TO 45KTS ACROSS THE PANHANDLE AND EASTERN WYOMING. WINTER IS NOT DONE WITH SOUTHEAST WYOMING AND WE NEED TO BE WATCHING THE EVOLUTION OF THIS EVENT AS HEAVY SNOW AND WINTER HEADLINES ARE DEFINITELY A POSSIBILITY FOR PORTIONS OF THE FORECAST AREA...POSSIBLY EVEN THE PANHANDLE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 536 AM MDT TUE MAY 5 2015 WIDESPREAD IFR/LIFR CEILINGS AND VISIBILITIES TO PERSIST ACROSS MUCH OF THE AREA THROUGH THE MORNING HOURS. SHOWERS BECOME WIDESPREAD ACROSS THE SOUTHERN PANHANDLE AND I-80 CORRIDOR LATE AFTERNOON INTO THE EVENING WITH IFR/LIFR CONDITIONS RETURNING. && .FIRE WEATHER... ISSUED AT 345 AM MDT TUE MAY 5 2015 A COOL AND WET WEATHER PATTERN WILL KEEP FIRE WEATHER CONCERNS VERY LOW THROUGH THE WEEKEND. AFTERNOON AND EVENING SHOWERS WILL BE POSSIBLE TODAY THROUGH THURSDAY...WITH GOOD CHANCES FOR MEASURABLE RAIN. MORE SUBSTANTIAL PRECIPITATION AMOUNTS ARE LOOKING POSSIBLE BY LATE FRIDAY INTO SUNDAY ASSOCIATED WITH A STRONG STORM SYSTEM. MINIMUM RELATIVE HUMIDITY VALUES SHOULD BE WELL ABOVE CRITICAL THRESHOLDS THROUGH THE PERIOD. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...DENSE FOG ADVISORY UNTIL 10 AM MDT THIS MORNING FOR WYZ116>118. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...GCC AVIATION...GCC FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS TUCSON AZ
235 PM MST TUE MAY 5 2015 .SYNOPSIS...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY NORTHEAST OF TUCSON INTO THIS EVENING. DRY CONDITIONS WILL THEN PREVAIL WEDNESDAY INTO EARLY NEXT WEEK. THE EXCEPTION WILL BE A FEW SHOWERS AND THUNDERSTORMS ACROSS THE WHITE MOUNTAINS SATURDAY. EXPECT BREEZY TO WINDY CONDITIONS DURING THE LATTER PART OF THE WEEK. BELOW NORMAL DAYTIME TEMPERATURES WILL OCCUR INTO SATURDAY FOLLOWED BY A SIGNIFICANT WARMING TREND EARLY NEXT WEEK. && .DISCUSSION...THE SYSTEM THAT BROUGHT SHOWERS AND THUNDERSTORMS TO THE AREA YESTERDAY AND LAST NIGHT WILL CONTINUE TO INFLUENCE THE WEATHER TODAY. RESIDUAL MOISTURE COMBINED WITH DAYTIME HEATING AND SOME SUPPORT FROM THE UPPER LOW WILL RESULT IN A FEW SHOWERS AND THUNDERSTORMS YET THIS EVENING. LATEST HRRR MODEL SOLUTION KEPT MOST OF THIS ACTIVITY NORTHEAST OF THE TUCSON METRO THIS EVENING. ALTHOUGH THE MODEL DEPICTED VERY SPOTTY ACTIVITY...SO WILL JUST KEEP LOW POP VALUES IN THE FORECAST FOR NOW. OTHERWISE...MODELS EJECT THE SYSTEM NORTHEAST INTO THE CENTRAL PLAINS BY TOMORROW MORNING RESULTING IN A BREAK IN THE RAIN CHANCES. HOWEVER...ANOTHER SYSTEM WAS PROGGED TO DROP SOUTH ALONG THE INTERIOR WEST COAST INTO CENTRAL CALIFORNIA ON THURSDAY. THIS NEXT SYSTEM WILL BRING STRONG AND GUSTY WINDS TO THE AREA AS EARLY AS TOMORROW AFTERNOON BUT MORE SO ON THURSDAY. MODELS TRACK THIS SYSTEM THROUGH NORTHERN ARIZONA FRIDAY INTO SATURDAY. FOR NOW...THE BEST CHANCE OF RAIN WILL BE ACROSS NORTHERN ARIZONA INTO THE WHITE MOUNTAINS MAINLY ON SATURDAY. THEREAFTER...A RIDGE OF HIGH PRESSURE WAS PROGGED TO BUILD OVER THE AREA BEFORE ANOTHER SYSTEM APPROACHES THE SOUTHERN CALIFORNIA COAST EARLY NEXT WEEK. DAYTIME TEMPERATURES WILL REMAIN BELOW NORMAL THIS WEEK. && .AVIATION...VALID THRU 07/00Z. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER THE WHITE MOUNTAINS NE OF KSAD INTO THIS EVENING. GUSTY AFTERNOON WINDS WILL DIMINISH TO NORMAL DIURNAL TRENDS AFTER SUNSET...GENERALLY LESS THAN 10 KTS THROUGH THE MORNING. LOW AND MID LEVEL CLOUDS DIMINISHING TONIGHT...WITH SCT HIGH CLOUDS MOVING IN LATE TONIGHT INTO WEDNESDAY MORNING. EXPECT STRONGER WINDS WEDNESDAY...15 TO 20 KTS GUSTING TO AROUND 30 KTS. AN EARLIER START TO WINDS WEDNESDAY...PICKING UP AROUND 16Z AT KSAD AND KDUG...17Z AT KTUS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A CHANCE OF SHOWERS AND THUNDERSTORMS CONTINUES MAINLY EAST OF TUCSON TODAY AND ACROSS THE WHITE MOUNTAINS INTO THIS EVENING. DRY CONDITIONS WILL THEN PREVAIL LATE TONIGHT. A LOW PRESSURE SYSTEM WILL STRENGTHEN NORTHWEST OF THE AREA WEDNESDAY INTO FRIDAY. THIS SYSTEM WILL PRODUCE BREEZY CONDITIONS WEDNESDAY AFTERNOON FOLLOWED BY BREEZY TO WINDY CONDITIONS THURSDAY AND FRIDAY. HOWEVER...DAYTIME MINIMUM RELATIVE HUMIDITIES AND FUEL MOISTURE WILL BE MARGINAL AT BEST TO PRODUCE CRITICAL FIRE CONDITIONS. A FEW SHOWERS AND THUNDERSTORMS MAY THEN OCCUR ACROSS THE WHITE MOUNTAINS SATURDAY AS THE LOW PRESSURE SYSTEM MOVES NORTH OF THE AREA. EXPECT LESS WIND THIS WEEKEND ALTHOUGH SOME AFTERNOON GUSTINESS WILL OCCUR DUE TO DAYTIME HEATING. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
334 PM MDT TUE MAY 5 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 328 PM MDT TUE MAY 5 2015 CURRENTLY...UPPER LOW LIFTING SLOWLY E-NE ALONG THE CO/NM BORDER...WITH DEEP E-SE FLOW DRIVING WIDESPREAD SHOWER ACTIVITY ACROSS THE AREA. LACK OF INSTABILITY HAS KEPT THUNDERSTORMS TO A MINIMUM...THOUGH A FEW LIGHTNING STRIKES HAVE BEGIN TO APPEAR ACROSS THE SAN LUIS VALLEY AS STRONGER CONVECTION ROTATES NORTHWARD OUT OF NEW MEXICO. RAINFALL RATES SO FAR TODAY HAVE BEEN FAIRLY MODEST...WITH 0.25-0.50 INCH PER HOUR UNDER THE HEAVIEST SHOWERS...MAINLY A TENTH OF INCH PER HOUR OR LESS UNDER THE LIGHTER ACTIVITY. TONIGHT...LATEST HRRR SUGGESTS BAND OF MODERATE TO HEAVY SHOWERS ALONG THE ARKANSAS RIVER AT 21Z WILL LIKELY BE THE LAST AREA OF ORGANIZED HEAVIER PRECIP THIS EVENING...WITH ACTIVITY LIFTING SLOWLY NORTHWARD AND WEAKENING AFTER 00Z. STILL A LOW THREAT OF AN ISOLATED TSRA THIS EVENING...ESPECIALLY SOUTHERN SECTIONS NEAR THE NM BORDER WHERE INSTABILITY (CAPES 200-400 J/KG) IS SLIGHTLY DEEPER...BUT OVERALL...CHANCE OF STRONGER CONVECTION AND EXTREME RAINFALL RATES APPEARS TO BE FAIRLY LOW...SO WILL LET FLASH FLOOD WATCH END SLIGHTLY EARLY WITH AFTERNOON FORECAST UPDATE. AS LOW LIFTS NORTHEAST ACROSS THE AREA OVERNIGHT...SCATTERED SHOWERS WILL CONTINUE OVER THE MOUNTAINS...WHILE DEVELOPING WESTERLY LOW/MID LEVEL FLOW GRADUALLY BRINGS AN END TO PRECIP OVER THE I-25 CORRIDOR AND EASTERN PLAINS AFTER 06Z. WON`T MENTION FOG IN THE FORECAST AS CLOUDS AND WEAK WESTERLY FLOW SHOULD KEEP VISIBILITY FROM DROPPING TOO MUCH...THOUGH WITH PLENTIFUL RAIN/BL MOISTURE AREAS OF GROUND FOG LOOK POSSIBLE...ESPECIALLY EL PASO COUNTY WHERE LOW LEVEL FLOW TAKES MUCH OF THE NIGHT TO TURN W-NW. WEDNESDAY...UPPER LOW LIFTS SLOWLY NORTHEAST INTO THE CENTRAL PLAINS BY LATE AFTERNOON WITH LOW AND MID LEVEL FLOW BECOMING MORE SWLY THROUGH THE DAY. MOISTURE DECREASES SOMEWHAT AS WELL...THOUGH WITH RATHER STEEP LAPSE RATES DEVELOPING DURING THE AFTERNOON AND WEAK UPPER WAVE LIFTING OUT OF THE SOUTHWEST...AT LEAST SCATTERED AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS WILL DEVELOP MANY AREAS. BEST CHANCES WILL BE ALONG THE CONTINENTAL DIVIDE AND NORTHERN AREAS...LESSER POPS FARTHER SOUTH AND SOUTHEAST WHERE DRIER AIR PUNCHES NORTHWARD FROM NM. MAX TEMPS WILL RECOVER ALL AREAS WITH MORE SUN AND LACK OF WIDESPREAD RAINFALL...AND A FEW SPOTS ON THE PLAINS WILL APPROACH 80F...WITH 60S AND 70S ACROSS MOST LOWER ELEVATIONS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 328 PM MDT TUE MAY 5 2015 ...WEATHER PATTERN TO REMAIN ACTIVE FOR NEXT SEVERAL DAYS... AFTER A BRIEF LULL WEDNESDAY...WEDNESDAY NIGHT THROUGH THURSDAY...LOW LEVEL UPSLOPE FLOW WILL REDEVELOP OVER THE EASTERN PLAINS...LEADING TO MORE SHOWER AND THUNDERSTORM CHANCES THURSDAY AFTERNOON AND EVENING...MAINLY FOR AREAS ALONG AND NEAR THE EASTERN MOUNTAINS ACROSS THE PIKES PEAK REGION...BUT ALSO FOR SPOTS OUT ON THE PLAINS. LOW LEVEL EASTERLY FLOW COMBINED WITH UPPER LEVEL SOUTHWEST FLOW WILL INCREASE SHEAR VALUES SUCH THAT A FEW SEVERE STORMS WILL BE POSSIBLE THURSDAY. THURSDAY NIGHT THROUGH FRIDAY...LOW LEVEL UPSLOPE BECOMES MORE FIRMLY ENTRENCHED ACROSS THE PLAINS. THE UPSLOPE LOOKS LIKE IT GETS DEEP ENOUGH TO BRING IN WIDESPREAD LOW CLOUDS AND AREAS OF LIGHT PRECIP...BUT POTENTIALLY REDUCES THE CONVECTIVE POTENTIAL THIS DAY...BY LIMITING THE AMOUNT OF HEATING. SEVERE STORMS PRESENTLY LOOK LESS LIKELY THIS DAY...BUT THIS IS CONTINGENT ON HOW DEEP THE UPSLOPE FLOW REALLY TURNS OUT TO BE. COULD STILL HAVE SOME PROBLEMS ALONG AND NEAR THE EAST SLOPES OF THE MOUNTAINS ACROSS THE PIKES PEAK REGION...ESPECIALLY LATE FRIDAY AFTERNOON AND EVENING. THEN...ON SATURDAY...WE BRING THE NEXT MAJOR NEGATIVE TILT TROUGH NORTHEAST INTO SOUTHERN COLORADO. THIS TROUGH LOOKS VIGOROUS...WITH THE POTENTIAL TO CREATE A LOT OF LIFT...AND GENERATE A LOT OF INTENSE CONVECTION...IN A STRONGLY SHEARED ATMOSPHERE. PROBLEM IS...NOT EXACTLY SURE WHAT TRAJECTORY THIS THING IS GOING TO TAKE AS IT EJECTS NORTHEAST ON SATURDAY. THE 12Z GFS AND THE OLD 00Z ECMWF TRACK IT FARTHER NORTH THAN SOME OF THE 06Z RUNS...GENERALLY YIELDING LESS SEVERE POTENTIAL. BUT...IF THE 06Z RUNS TURN OUT TO BE MORE TRUE TO FORM...WATCH OUT. COULD BE BIG SEVERE WEATHER DAY OVER THE EAST...WITH TORNADO POTENTIAL AS WELL AS HAIL/WIND POTENTIAL. THEN...AS WE MOVE INTO SUNDAY...THINGS SHIFT OVER MORE TOWARD WINTER WEATHER AS WE GET ON THE BACK SIDE OF THE SATURDAY SYSTEM. COLD AIR ON THE BACK SIDE OF THE SYSTEM COULD BRING SNOW TO THE MOUNTAINS... AND POSSIBLY DOWN TO THE LEVEL OF EL PASO COUNTY. FARTHER EAST... AWAY FROM THE MOUNTAINS...IT WOULD LIKELY BE JUST SPOTTY LIGHTER AMOUNTS OF RAIN. NORTHWEST FLOW COULD BRING MORE RAIN AND SNOW SHOWERS TO THE MOUNTAINS ON MONDAY. AND THEN...BY TUESDAY...IT`S LOOKING LIKE ANOTHER ROUND OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS. A LOT OF WEATHER TO TAKE PLACE OVER THE NEXT 7 DAYS. DETAILS PRESENTED NOW WILL INEVITABLY CHANGE. PLEASE KEEP CHECKING BACK FOR LATER UPDATES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 328 PM MDT TUE MAY 5 2015 AT KALS...PERIODS OF SHOWERS EXPECTED INTO EARLY EARLY EVENING...WITH AN ISOLATED TSRA ALSO POSSIBLE. IN BETWEEN SHOWERS...PREVAILING CONDITIONS WILL BE MAINLY VFR...WHILE UNDER THE HEAVIER PRECIP MVFR CIGS/VIS ARE LIKELY. PRECIP DIMINISHES LATE THIS EVENING AND OVERNIGHT...THOUGH MID-LEVEL CLOUD DECK WILL BE SLOW TO CLEAR. ON WED...VFR WITH SCT -SHRA AND ISOLD -TSRA AFTER 18Z. AT KCOS...RAIN SHOWERS WILL CONTINUE INTO THE EVENING WITH MAINLY MVFR CONDITIONS...THOUGH SOME BRIEF IFR IS POSSIBLE UNDER THE HEAVIER SHOWERS. LATE THIS EVENING AND OVERNIGHT SHOWERS WILL GRADUALLY DIMINISH...THOUGH CIGS WILL BE SLOW TO LIFT WITH MVFR AND AREAS OF IFR LIKELY TO PERSIST THROUGH THE NIGHT. MAY ALSO HAVE TO DEAL WITH AT LEAST PATCHY AREAS OF FOG AS WELL WITH VERY WET GROUND AND MOIST BOUNDARY LAYER. ON WED...ANY LOW CLOUDS SHOULD BREAK BY MID MORNING WITH VFR CONDITIONS THROUGH THE DAY...THOUGH THERE WILL BE A CHANCE OF TSRA AFTER 20Z. AT KPUB...EXPECT PERIODS OF SHOWERS TO PERSIST INTO THE EVENING WITH MVFR CONDITIONS UNDER THE HEAVIER PRECIP AND BRIEF VFR IN BETWEEN SHOWERS. LATE THIS EVENING AND OVERNIGHT PRECIP WILL DIMINISH...THOUGH AREAS OF MVFR CIGS WILL PERSIST ALONG WITH PATCHY GROUND FOG AS WELL. ON WED...VFR FROM MID MORNING ONWARD WITH SCT - SHRA AND ISOLD -TSRA AFTER 20Z. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...LW AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
245 PM CDT TUE MAY 5 2015 .UPDATE... UPDATED TEMPERATURES AND WEATHER FOR THE REST OF TODAY. IT APPEARS THE BEST CHANCES FOR SHOWERS AND THUNDERSTORM REDEVELOPMENT THIS AFTERNOON WILL BE PRIMARILY ALONG AND SOUTH OF INTERSTATE 80 IN CLOSER PROXIMATE TO THE NORTHWARD ADVANCING SURFACE BOUNDARY. TEMPERATURES ACROSS CENTRAL ILLINOIS..SOUTH OF THIS BOUNDARY ARE ALREADY WELL INTO THE 70S TO NEAR 80 IN MANY LOCATIONS...WITH DEW POINTS POOLING INTO THE LOWER TO MID 60S RIGHT ALONG THE BOUNDARY. MODIFYING THE 12 UTC ILX SOUNDING WITH THESE SURFACE CONDITIONS YIELDS SCAPE AROUND 1300 J/KG WITH VERY LITTLE CAP. WITH THIS IN MIND...IN SPITE OF THE FACT THAT THERE IS NO SIGNIFICANT MID LEVEL DISTURBANCE EXPECTED TO MOVE OVER THE AREA THIS AFTERNOON...IT SEEMS PROBABLE THAT SCT CONVECTION WILL STILL CONTINUE TO BUBBLE UP THIS AFTERNOON WITHIN THE VICINTY OF THIS SURFACE BOUNDARY...WHERE INSTABILITY AND SURFACE CONVERGENCE WILL BE MAXIMIZED. FARTHER NORTH...VERY COOL AND STABLE CONDITIONS SHOULD LIMIT SHOWER AND THUNDERSTORM POTENTIAL. THEREFORE...I HAVE POINTED THE FORECAST IN THIS DIRECTION. TEMPERATURES ACROSS MUCH OF THE CHICAGO AREA NEAR LAKE MICHGAN WILL LIKELY REMAIN IN THE LOW TO MID 50S TODAY. HOWEVER...FARTHER INLAND AND SOUTH...EXPECT TEMPERATURES WELL INTO THE 70S...ESPECIALLY SOUTH OF INTERSTATE 80. KJB && .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * EAST-NORTHEAST WINDS AROUND 10 KT THROUGH THIS AFTERNOON. * IFR/LIFR CIGS THROUGH THE BEGINNING OF THE MORNING RUSH WEDNESDAY. * IFR/LIFR VSBYS AT ORD THROUGH EARLY TOMORROW. RETURNING TO MDW TONIGHT. * SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN...MAINLY SOUTH OF MDW. KMD //DISCUSSION...UPDATED 18Z... THE BATTLE OF THE COLD LAKE AND LOW LEVEL ONSHORE FLOW VERSUS THE WARM MAY SUN IS UNDERWAY...MAKING FOR A CHALLENGING AFTERNOON FORECAST ACROSS THE TERMINALS. MONITORING WEBCAMS DOWNTOWN SHOW CLOUDS BRIEFLY ATTEMPTING TO LIFT BEFORE FILLING RIGHT BACK IN. WE ALSO CONTINUE TO ADVECT WARMER AND MOIST AIR JUST OFF THE DECK WHICH IS AIDING IN KEEPING THE LOW LEVEL INVERSION IN PLACE. FEEL THAT THESE LATTER FACTORS WILL WIN OUT AND KEEP MOST OF THE TAF SITES LOCKED IN LIFR TO IFR CONDITIONS...WHILE POINTS SOUTH WILL LIFT TO VFR BEFORE MVFR CUMULUS FILL IN AS WELL. THE LOW LEVEL FRONT IS NOT EXPECTED TO LIFT MUCH FARTHER NORTH...AND THUS EXPECT THE NNE WINDS TO REMAIN IN PLACE. WITH THE FRONT HOLDING SOUTH...EXPECT ANY CONVECTION THAT STIRS THIS AFTERNOON TO BE FOCUSED IN THESE AREAS...SOUTH OF INTERSTATE 80. TONIGHT WINDS SHOULD WEAKEN SOME AND EXPECT CIGS/VSBYS TO REMAIN LOCKED IN DOWN LOW MOST OF THE NIGHT. FOG COULD BE DENSE TONIGHT...ESPECIALLY CLOSER TO THE LAKE. LOW LEVEL FRONT GETS SOME NORTHWARD MOVEMENT EARLY WEDS WHICH SHOULD ALLOW FOR SOME LIFTING WEDNESDAY MORNING. PRECIP CHANCES DO EXIST TONIGHT/EARLY WEDS BUT TOO LOW FOR A MENTION IN THE TAFS JUST YET. AT BEST SOME ISOLATED SHOWERS AHEAD OF THE FRONT 8Z-12Z TIME FRAME FOR THE TAF SITES. KMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH THAT EAST-NORTHEAST WINDS HOLD AROUND 10 KT THIS AFTERNOON. * HIGH IN LIFR CIGS HOLDING AT ORD... AND IFR/LIFR CIGS RETURNING TO MDW. MEDIUM ON CIG HEIGHTS OVERNIGHT THOUGH LOW-MEDIUM ON CLEARING TIME WEDS. * MEDIUM-LOW ON VSBYS THIS AFTERNOON AND TONIGHT. COULD BE WORSE VSBY OVERNIGHT. * HIGH IN ORD REMAINING DRY THE REST OF THE DAY. MEDIUM THAT AFTERNOON SHOWERS/ISOLATED T-STORMS REMAIN SOUTH OF MDW. MEDIUM THAT TAF SITES REMAIN DRY OVERNIGHT AS WELL. KMD //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. SOUTHEAST WINDS BCMG SOUTH. THURSDAY...VFR. SOUTH WINDS. FRIDAY...TSRA. MVFR CIGS PSBL OVERNIGHT. SOUTHWEST WINDS. SATURDAY...SCHC TSRA DURING THE DAY AND CHC SHRA. NORTHWEST WINDS. SUNDAY AND MONDAY...CHC TSRA. MVFR CIGS PSBL. NORTHEAST WINDS BCMG SOUTHWEST MONDAY. JEE && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ006-ILZ014 UNTIL 11 AM WEDNESDAY. IN...NONE. LM...DENSE FOG ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745- LMZ777-LMZ779 UNTIL 4 PM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
111 PM CDT TUE MAY 5 2015 .UPDATE...1135 AM CDT UPDATED TEMPERATURES AND WEATHER FOR THE REST OF TODAY. IT APPEARS THE BEST CHANCES FOR SHOWERS AND THUNDERSTORM REDEVELOPMENT THIS AFTERNOON WILL BE PRIMARILY ALONG AND SOUTH OF INTERSTATE 80 IN CLOSER PROXIMATE TO THE NORTHWARD ADVANCING SURFACE BOUNDARY. TEMPERATURES ACROSS CENTRAL ILLINOIS..SOUTH OF THIS BOUNDARY ARE ALREADY WELL INTO THE 70S TO NEAR 80 IN MANY LOCATIONS...WITH DEW POINTS POOLING INTO THE LOWER TO MID 60S RIGHT ALONG THE BOUNDARY. MODIFYING THE 12 UTC ILX SOUNDING WITH THESE SURFACE CONDITIONS YIELDS SCAPE AROUND 1300 J/KG WITH VERY LITTLE CAP. WITH THIS IN MIND...IN SPITE OF THE FACT THAT THERE IS NO SIGNIFICANT MID LEVEL DISTURBANCE EXPECTED TO MOVE OVER THE AREA THIS AFTERNOON...IT SEEMS PROBABLE THAT SCT CONVECTION WILL STILL CONTINUE TO BUBBLE UP THIS AFTERNOON WITHIN THE VICINTY OF THIS SURFACE BOUNDARY...WHERE INSTABILITY AND SURFACE CONVERGENCE WILL BE MAXIMIZED. FARTHER NORTH...VERY COOL AND STABLE CONDITIONS SHOULD LIMIT SHOWER AND THUNDERSTORM POTENTIAL. THEREFORE...I HAVE POINTED THE FORECAST IN THIS DIRECTION. TEMPERATURES ACROSS MUCH OF THE CHICAGO AREA NEAR LAKE MICHGAN WILL LIKELY REMAIN IN THE LOW TO MID 50S TODAY. HOWEVER...FARTHER INLAND AND SOUTH...EXPECT TEMPERATURES WELL INTO THE 70S...ESPECIALLY SOUTH OF INTERSTATE 80. KJB && .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * EAST-NORTHEAST WINDS AROUND 10 KT THROUGH THIS AFTERNOON. * IFR/LIFR CIGS THROUGH THE BEGINNING OF THE MORNING RUSH WEDNESDAY. * IFR/LIFR VSBYS RETURNING TONIGHT. * SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN...MAINLY SOUTH OF MDW. KMD //DISCUSSION...UPDATED 18Z... THE BATTLE OF THE COLD LAKE AND LOW LEVEL ONSHORE FLOW VERSUS THE WARM MAY SUN IS UNDERWAY...MAKING FOR A CHALLENGING AFTERNOON FORECAST ACROSS THE TERMINALS. MONITORING WEBCAMS DOWNTOWN SHOW CLOUDS BRIEFLY ATTEMPTING TO LIFT BEFORE FILLING RIGHT BACK IN. WE ALSO CONTINUE TO ADVECT WARMER AND MOIST AIR JUST OFF THE DECK WHICH IS AIDING IN KEEPING THE LOW LEVEL INVERSION IN PLACE. FEEL THAT THESE LATTER FACTORS WILL WIN OUT AND KEEP MOST OF THE TAF SITES LOCKED IN LIFR TO IFR CONDITIONS...WHILE POINTS SOUTH WILL LIFT TO VFR BEFORE MVFR CUMULUS FILL IN AS WELL. THE LOW LEVEL FRONT IS NOT EXPECTED TO LIFT MUCH FARTHER NORTH...AND THUS EXPECT THE NNE WINDS TO REMAIN IN PLACE. WITH THE FRONT HOLDING SOUTH...EXPECT ANY CONVECTION THAT STIRS THIS AFTERNOON TO BE FOCUSED IN THESE AREAS...SOUTH OF INTERSTATE 80. TONIGHT WINDS SHOULD WEAKEN SOME AND EXPECT CIGS/VSBYS TO REMAIN LOCKED IN DOWN LOW MOST OF THE NIGHT. FOG COULD BE DENSE TONIGHT...ESPECIALLY CLOSER TO THE LAKE. LOW LEVEL FRONT GETS SOME NORTHWARD MOVEMENT EARLY WEDS WHICH SHOULD ALLOW FOR SOME LIFTING WEDNESDAY MORNING. PRECIP CHANCES DO EXIST TONIGHT/EARLY WEDS BUT TOO LOW FOR A MENTION IN THE TAFS JUST YET. AT BEST SOME ISOLATED SHOWERS AHEAD OF THE FRONT 8Z-12Z TIME FRAME FOR THE TAF SITES. KMD //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH THAT EAST-NORTHEAST WINDS HOLD AROUND 10 KT THIS AFTERNOON. * HIGH IN LIFR CIGS HOLDING OR LIFTING SLIGHTLY AT ORD... AND IFR/LIFR CIGS RETURNING TO MDW. MEDIUM ON CIG HEIGHTS OVERNIGHT THOUGH LOW-MEDIUM ON CLEARING TIME WEDS. * MEDIUM-LOW ON VSBYS THIS AFTERNOON AND TONIGHT. COULD BE WORSE VSBY OVERNIGHT. * HIGH IN ORD REMAINING DRY THE REST OF THE DAY. MEDIUM-HIGH THAT AFTERNOON SHOWERS/ISOLATED T-STORMS REMAIN SOUTH OF MDW. MEDIUM THAT TAF SITES REMAIN DRY OVERNIGHT AS WELL. KMD //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. SOUTHEAST WINDS BCMG SOUTH. THURSDAY...VFR. SOUTH WINDS. FRIDAY...TSRA. MVFR CIGS PSBL OVERNIGHT. SOUTHWEST WINDS. SATURDAY...SCHC TSRA DURING THE DAY AND CHC SHRA. NORTHWEST WINDS. SUNDAY AND MONDAY...CHC TSRA. MVFR CIGS PSBL. NORTHEAST WINDS BCMG SOUTHWEST MONDAY. JEE && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1249 PM CDT TUE MAY 5 2015 .UPDATE... ISSUED AT 1045 AM CDT TUE MAY 5 2015 15Z/10AM SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY EXTENDING FROM NORTH-CENTRAL ILLINOIS INTO CENTRAL IOWA...GENERALLY ALONG A KANKAKEE...TO PEORIA...TO DES MOINES LINE. WIDESPREAD RAIN CONTINUES TO FALL NORTH OF THE FRONT: HOWEVER, MOSTLY SUNNY AND DRY CONDITIONS PREVAIL TO THE SOUTH ACROSS CENTRAL ILLINOIS. TEMPERATURES HAVE ALREADY RISEN WELL INTO THE 70S ACROSS ALL BUT THE FAR NORTHERN KILX CWA. BASED ON THE 12Z UPPER AIR SOUNDING AND ASSUMING MIXING UP TO ABOUT 750MB SIMILAR TO YESTERDAY AFTERNOON...HIGHS TODAY SHOULD REACH THE LOWER TO MIDDLE 80S. HAVE ADJUSTED TEMPS UP BY A FEW DEGREES ACCORDINGLY. && .SHORT TERM...(TODAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 A FRONTAL BOUNDARY IS ORIENTED WEST-EAST ACROSS CENTRAL IL THIS MORNING WITH PRECIPITATION IN ISENTROPIC ASCENT REGION LARGELY TO THE NORTH OF THE BOUNDARY. MODELS INDICATE THE BOUNDARY AND PRECIPITATION WILL SHIFT SLOWLY NORTHWARD TODAY. WEAK DISTURBANCES MOVING ALONG THE BOUNDARY WILL PRODUCE SOME ENHANCEMENTS IN CONVECTIVE SHOWER COVERAGE IN THE VICINITY...EARLY THIS MORNING FROM AROUND THE ILLINOIS RIVER NORTHWESTWARD...AND LATE IN THE AFTERNOON NORTH OF THE I-74 CORRIDOR. FOR THE MOST PART...CONVECTION SHOULD BE WEAK AT THIS POINT WITH ONLY WEAK MID-LEVEL INSTABILITY REMAINING THROUGH THE NIGHT...AND 0-6KM BULK SHEAR UP TO 25-30 KTS THIS MORNING DIMINISHING SUBSTANTIALLY FOR THE AFTERNOON. 1000-1500 JOULES OF SURFACE-BASED CAPE SHOULD BE ABLE TO DEVELOP WITH AFTERNOON HEATING ALONG/NORTH OF I-72 AND CAN`T RULE OUT ISOLATED THUNDERSTORMS SOUTHWARD TO I-72 AS A RESULT. .LONG TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 332 AM CDT TUE MAY 5 2015 ONGOING CONVECTION ALONG THE BOUNDARY OVER NORTHERN ILLINOIS THIS MORNING NOT ONLY DRIVING THE WEATHER THROUGHOUT THE DAY, BUT INTO THE OVERNIGHT AS WELL. GFS AND NAM CONTINUE TO KEEP A BIT OF PRECIP PRETTY FAR SOUTH, AS FAR SOUTH AS A LINE FROM HAVANA TO BLOOMINGTON. HOWEVER, THE RAP/RUC AND THE HRRR ARE PUSHING THE AREA OF CONVECTION WELL TO THE NORTH THROUGH THE MORNING WITH THE BOUNDARY. WHEN THE SECONDARY WAVE RIPPLES THROUGH THE REGION AFTER 00Z, IT WOULD BE DISPLACED NORTH OF THE FA. THE 4KM WRF HAS JUST THAT SOLUTION, STARTING MORE IN LINE WITH THE RAP/RUC AND HRRR...AND KEEPING THE FA DRY AFTER 00Z, BUT A LITTLE MORE GENEROUS WITH SOME ISOLATED INSTABILITY SHOWERS. HAVE KEPT ISO TS IN THE NORTH, MAINLY ALONG AND NORTH OF I-74 FOR THE EARLY EVENING. HIGH PRESSURE BEGINS TO BUILD BACK INTO THE REGION LATER TONIGHT, SOUTHERLY WINDS PUSHING THE FRONT BACK TO THE NORTH AND OUT OF THE FORECAST AREA THROUGH WED NIGHT. FORECAST REMAINS ROUGHLY THE SAME BEYOND DAY 3... PRECIP CHANCES SLOWLY EDGING BACK INTO WEST CENTRAL ILLINOIS FOR THURSDAY AS AN UPPER LEVEL WAVE PUSHES OUT OF THE SW. THE ENERGY IS PART OF A GENERAL PATTERN SHIFT TO MORE SOUTHWESTERLY FLOW WITH THE UPPER LEVEL TROF DIGGING BACK IN OVER THE SWRN CONUS. THE SFC LOW MOVES OUT INTO THE UPPER MIDWEST AND INTO CANADA BY THE END OF THE WEEK, BUT IN SHIFTING TO MORE SOUTHWESTERLY FLOW ALOFT, OPENS THE DOOR TO A SERIES OF SHORTWAVES THAT KEEP THE FORECAST WET FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND. TEMPS RATHER WARM THROUGH THE FORECAST WITH OVERCAST AND RAINY SKIES KEEPING THE OVERNIGHT LOWS UP A BIT, BUT LIKELY NOT NEARLY AS WARM AS THE TREND IN THE GUIDANCE. HAVE KNOCKED THEM DOWN A COUPLE DEGREES. SOUTHERLY FLOW AND A RELATIVELY WARM AIRMASS KEEPING THE HIGHS A BIT ABOVE NORMS, EVEN WITH THE PASSAGE OF THE FIRST LOW SKIRTING TO THE NW...THE MID LEVELS REMAIN WARM UNTIL THE MAIN TROF OVER THE SW LIFTS INTO AND OUT OF THE GREAT LAKES. COOLER AIR IN THE MIDLEVELS IS ONLY AROUND FOR 36 HOURS DAY 7/8 BEFORE THE WARM AIRMASS REESTABLISHES ITSELF. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1249 PM CDT TUE MAY 5 2015 LATEST SURFACE ANALYSIS CONTINUES TO SHOW NEARLY STATIONARY FRONTAL BOUNDARY DRAPED ACROSS NORTH-CENTRAL ILLINOIS FROM JUST NORTH OF KGBG TO SOUTH OF KPNT. WINDS IN THE VICINITY OF THE BOUNDARY ARE LIGHT/VARIABLE AT KPIA...BUT ARE SOUTHWESTERLY AT 10 TO 15KT FURTHER SOUTH AT THE REMAINING TERMINALS. HIGH-RES MODELS SUGGEST THE FRONT WILL SINK SLIGHTLY SOUTHWARD LATER THIS AFTERNOON AND EVENING...RESULTING IN A WIND SHIFT TO THE E/NE AT BOTH KPIA AND KBMI. MODELS DIFFER ON THE EXACT TIMING...WITH THE HRRR SHOWING THE SHIFT AT ABOUT 22Z. AFTER THAT...THE FRONT WILL REMAIN IN PLACE ALONG/JUST SOUTH OF I-74 THROUGHOUT THE NIGHT. HAVE CONTINUED WITH A LIGHT E/NE WIND AT KPIA AND KBMI ACCORDINGLY...WITH SOUTHERLY WINDS AT KSPI AND KDEC. THE FRONT WILL FINALLY GET A SOLID PUSH NORTHWARD BY WEDNESDAY MORNING...ALLOWING WINDS TO BECOME SOUTHERLY AT ALL TAF SITES. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARNES SHORT TERM...ONTON LONG TERM...HJS AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1150 AM CDT TUE MAY 5 2015 .UPDATE... 1135 AM CDT UPDATED TEMPERATURES AND WEATHER FOR THE REST OF TODAY. IT APPEARS THE BEST CHANCES FOR SHOWERS AND THUNDERSTORM REDEVELOPMENT THIS AFTERNOON WILL BE PRIMARILY ALONG AND SOUTH OF INTERSTATE 80 IN CLOSER PROXIMATE TO THE NORTHWARD ADVANCING SURFACE BOUNDARY. TEMPERATURES ACROSS CENTRAL ILLINOIS..SOUTH OF THIS BOUNDARY ARE ALREADY WELL INTO THE 70S TO NEAR 80 IN MANY LOCATIONS...WITH DEW POINTS POOLING INTO THE LOWER TO MID 60S RIGHT ALONG THE BOUNDARY. MODIFYING THE 12 UTC ILX SOUNDING WITH THESE SURFACE CONDITIONS YIELDS SCAPE AROUND 1300 J/KG WITH VERY LITTLE CAP. WITH THIS IN MIND...IN SPITE OF THE FACT THAT THERE IS NO SIGNIFICANT MID LEVEL DISTURBANCE EXPECTED TO MOVE OVER THE AREA THIS AFTERNOON...IT SEEMS PROBABLE THAT SCT CONVECTION WILL STILL CONTINUE TO BUBBLE UP THIS AFTERNOON WITHIN THE VICINTY OF THIS SURFACE BOUNDARY...WHERE INSTABILITY AND SURFACE CONVERGENCE WILL BE MAXIMIZED. FARTHER NORTH...VERY COOL AND STABLE CONDITIONS SHOULD LIMIT SHOWER AND THUNDERSTORM POTENTIAL. THEREFORE...I HAVE POINTED THE FORECAST IN THIS DIRECTION. TEMPERATURES ACROSS MUCH OF THE CHICAGO AREA NEAR LAKE MICHGAN WILL LIKELY REMAIN IN THE LOW TO MID 50S TODAY. HOWEVER...FARTHER INLAND AND SOUTH...EXPECT TEMPERATURES WELL INTO THE 70S...ESPECIALLY SOUTH OF INTERSTATE 80. KJB && .SHORT TERM... 329 AM CDT THROUGH TONIGHT... A LOOSELY-DEFINED AND NON-INTENSE MCS IS MOVING ACROSS NORTHERN ILLINOIS DURING THE PREDAWN WITHIN A BROAD ZONE OF WARM ADVECTION. RADAR MOSAIC AND VAD WIND PROFILER DATA INDICATE THE PRESENCE OF A MID-LEVEL SHORT WAVE THAT LIKELY MAY BE CONVECTIVELY-ENHANCED HELPING TO FOCUS THE BULK OF THE RAIN AND EMBEDDED THUNDER. BASED ON RADAR TRENDS...HAVE GONE A LITTLE FURTHER SOUTH WITH RAIN AND THUNDER CHANCES THROUGH 9 AM OR SO COMPARED TO THE SUITE OF HIGH- RESOLUTION GUIDANCE. OVERALL EXPECT THE COVERAGE OF PRECIPITATION TO CONSIDERABLY DIMINISH DURING THE MID TO LATE MORNING HOURS WITH THE WAVE PASSING NORTHEAST. TRAILING SHOWERS AND A FEW STORMS ARE LIKELY TO LINGER ALONG AND NORTH OF I-80 DURING THE LATTER MORNING. WHILE THE MID-LEVEL FLOW IS EXPECTED TO BECOME LESS DISTURBED BY AFTERNOON PER WATER VAPOR ANALYSIS AND RAP AND NAM FORECASTS...THE CHANCES FOR AFTERNOON CONVECTION LINGER IN THE HIGH PWAT AIR /1.4 INCHES +/. THESE CHANCES WILL BE ATTACHED TO OUTFLOWS/CONVERGENCE ZONES TRAILING THE MORNING SHORT WAVE AND ITS CONVECTION...AS WELL AS THE SYNOPTIC CONVERGENCE ALONG THE STATIONARY FRONT THAT EARLY THIS MORNING IS ROUGHLY NEAR I-74. THIS FEATURE IS EXPECTED TO CREEP NORTHWARD THIS MORNING WITH THE DECAY OF CONVECTION AND HEATING IN THE WARM SECTOR. THIS FRONT WILL SEPARATE TEMPERATURES LIKELY AROUND 80 IN THE SOUTHERN FORECAST AREA TO THE COOLER AND CLOUDY 60S IN NORTHEAST ILLINOIS...WITH EVEN LOWER TO MID 50S ALONG THE LAKE SHORE. DEW POINTS IN THE LOWER-MID 60S ALONG THE BOUNDARY WILL PROVIDE MARGINAL BUT SOME MIXED LAYER INSTABILITY NEAR THE BOUNDARY THIS AFTERNOON. CONVECTIVE ALLOWING MODELS GENERALLY SHOW DEVELOPMENT THIS AFTERNOON BUT VARY WIDELY IN COVERAGE. WITH WEAK MID-LEVEL FLOW AND BUILDING HEIGHTS NOT EXPECTING ANYTHING SEVERE AND HAVE GONE WITH SCATTERED OR CHANCE WORDING DEPENDING ON THE AREA. THE PRESENT MOST FAVORED FOCUS THIS AFTERNOON LOOKS TO BE ALONG I-80 AND JUST NORTH OF...BUT THAT COULD CERTAINLY SHIFT OR BE MORE DIFFUSE...AND THE DAY SHIFT WILL BE ABLE TO BETTER ASSESS POST- MORNING CONVECTIVE TRENDS. MODELS AGREE ANY SHOWERS/STORMS THIS AFTERNOON WILL WANE IN THE EVENING BEING MORE DIURNALLY DRIVEN. THE FRONTAL BOUNDARY WILL LIKELY NOT MAKE TOO MUCH PROGRESS NORTH DURING THE NIGHT...HANGING AROUND I-80 OR SO. THE HIGH ABSOLUTE MOISTURE ALONG THE BOUNDARY COULD RESULT IN FOG ACROSS THE AREA...SOME OF WHICH MAY BE DENSE AND LINGER INTO EARLY WEDNESDAY MORNING. HAVE ADDED SOME GENERAL MENTION INTO THE FORECAST FOR THE TIME BEING. MTF && .LONG TERM... 329 AM CDT WEDNESDAY NIGHT THROUGH MONDAY... ATTENTION IN THE LONG RANGE IS FIRST ON THE IMPRESSIVE EARLY MAY WARMTH THAT WILL MAKE IT FEEL LIKE SUMMER IN SOME PLACES WEDNESDAY AND AREAWIDE THURSDAY AND POTENTIALLY FRIDAY TOO. THE UPPER JET PATTERN COMING IN FROM THE PACIFIC ON WEDNESDAY INTO THURSDAY CARVES A MORE AMPLIFIED PATTERN...FAVORING BUILDING HEIGHTS AND LOW-LEVEL SOUTHERLY FLOW TO INCREASE. GIVEN ALREADY ABOVE-NORMAL TEMPERATURES UP TO CENTRAL ILLINOIS IN RECENT DAYS...THIS SYNOPTIC PATTERN WILL FAVOR REPLENISHING AND ADDING TO THAT WARMTH AS WELL AS SPREADING IT NORTH. THE FRONTAL BOUNDARY IS LIKELY TO BREAK DOWN SOMEWHAT ON WEDNESDAY AS JUST BROAD SOUTHERLY FLOW BEGINS. THIS FLOW WILL NOT BE STRONG ENOUGH TO PREVENT LAKE COOLED AIR TO LIKELY REMAIN OVER NORTHEAST ILLINOIS AND POSSIBLY EVEN FAR NORTHWEST INDIANA. APART FROM THE MID 60S TO MID 70S IN THESE AREAS...LOWER TO POSSIBLY MID 80S ARE EXPECTED ACROSS THE SOUTHERN AND FAR WESTERN FORECAST AREA. THURSDAY WILL SEE SOUTH-SOUTHWEST WINDS INCREASE ENOUGH TO PREVENT ANY LAKE COOLING. A THERMAL RIDGE DEFINED BY 925MB TEMPERATURES OF 18C-19C AND 850MB TEMPERATURES OF 13-14C. USING REANALYSIS DATA SINCE 1979...WHEN THESE WARM OF TEMPERATURES HAVE BEEN EXPERIENCED IN THE FIRST HALF OF MAY IT YIELDS AN AVERAGE HIGH OF 83 DEGREES AT CHICAGO OHARE. WITH SUNSHINE HIGHLY LIKELY ON THURSDAY GIVEN THE AMPLIFIED FLOW KEEPING CIRRUS/DEBRIS AWAY ON MODEL SOLUTIONS...HAVE BOOSTED TEMPERATURES TO THESE VALUES AND EVEN SLIGHTLY HIGHER. SOME UPPER 80S ARE CERTAINLY POSSIBLE GIVEN THIS PATTERN. THE RECORD HIGH FOR CHICAGO ON THURSDAY MAY 7TH IS 87 DEGREES SET IN 1964. THE SECOND FOCUS ON THE LONG RANGE IS CONVECTIVE CHANCES. THE POTENTIAL BEGINS FRIDAY WITH A NORTHERN STREAM FRONT EASING TOWARD THE AREA...WHICH WILL COOL TEMPERATURES FOR SATURDAY AND POSSIBLY SUNDAY TOO...ESPECIALLY FOR LAKE ADJACENT AREAS. AS THE UPPER- LEVEL SOUTHWESTERLY FLOW INCREASES LATER IN THE WEEKEND...STORM CHANCES WILL INCREASE AS HIGH PWAT AIR IS AGAIN FORECAST TO ESTABLISH ITSELF ACROSS THE CORN BELT REGION. TIMING OF SHOWERS AND STORMS LOOK TO AGAIN BE TIED TO MID-LEVEL IMPULSES WHICH CAN OFTEN BE SUBTLE...WHICH DIMINISHES PREDICTABILITY AT THIS POINT...SO CONTINUE WITH CHANCES. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * EAST-NORTHEAST WINDS INCREASING BACK TO 10 KT THIS AFTERNOON. * IFR CIGS POSSIBLY LIFTING TO MVFR THIS AFTERNOON...RETURNING TO LIFR TONIGHT. * SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTN...MAINLY ALONG AND MORE LIKELY SOUTH OF MDW. KMD //DISCUSSION...UPDATED 12Z... THE RAIN IS SLOWLY SHIFTING NORTHEAST AND WILL CLEAR THE REGION THIS MORNING. NO ADDITIONAL LIGHTNING STRIKES ARE ANTICIPATED WITH THESE SHOWERS. THERE ARE SCATTERED REPORTS OF MVFR CIGS AND THE CIGS SHOULD LIFT TO VFR BEHIND THE SHOWERS. A STATIONARY FRONT WILL REMAIN SOUTH OF THE TERMINALS TODAY AND COULD SEE SHOWERS AND PERHAPS A THUNDERSTORM FIRE ALONG THE FRONT THIS AFTERNOON. THE SHOWERS AND STORMS COULD IMPACT THE EASTERN TERMINALS...BUT DUE TO LOW CONFIDENCE ONLY HAVE A VCSH. THINKING RFD WILL NOT BE IMPACTED. EAST WINDS AT 10 KT DIMINISH TO BELOW 10 KT THIS EVENING AND THEN BEGIN TO BACK TO SOUTHEAST TOMORROW AS THE FRONT LIFTS NORTH. JEE //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM-HIGH THAT EAST-NORTHEAST WINDS PICK BACK UP TO AROUND 10 KT THIS AFTERNOON. * MEDIUM-HIGH CONFIDENCE IN ORD REMAINING DRY THE REST OF THE DAY. MEDIUM THAT AFTERNOON SHOWERS/ISOLATED T-STORMS REMAIN SOUTH OF MDW. * MEDIUM CONFIDENCE IN IFR CIGS LIFTING TO MVFR BUT LOW ON TIMING AND DURATION. HIGH THAT IFR/LIFR CIGS AND VSBYS RETURN TONIGHT BUT LOW ON TIMING. KMD //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. SOUTHEAST WINDS BCMG SOUTH. THURSDAY...VFR. SOUTH WINDS. FRIDAY...TSRA. MVFR CIGS PSBL OVERNIGHT. SOUTHWEST WINDS. SATURDAY...SCHC TSRA DURING THE DAY AND CHC SHRA. NORTHWEST WINDS. SUNDAY AND MONDAY...CHC TSRA. MVFR CIGS PSBL. NORTHEAST WINDS BCMG SOUTHWEST MONDAY. JEE && .MARINE... 212 AM CDT A STATIONARY FRONT IS OVER CENTRAL IL AND IT WILL REMAIN SOUTH OF THE LAKE UNTIL IT LIFTS NORTH AS A WARM FRONT WEDNESDAY. THEREFORE...NORTHEAST TO EAST WINDS WILL BECOME SOUTH WEDNESDAY NIGHT BEHIND THE WARM FRONT. HIGH PRESSURE CURRENTLY OVER LAKE SUPERIOR SHIFTS EAST OF LAKE MICHIGAN WEDNESDAY AND REMAINS OVER THE EASTERN SEABOARD THROUGH THE WEEK. SOUTH WINDS UP TO 20 KT AT TIMES ARE EXPECTED THROUGH FRIDAY. THE NEXT LOW FORMS OVER THE NORTHERN ROCKIES WEDNESDAY AND MOVES OVER ONTARIO THURSDAY NIGHT AND FRIDAY. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SATURDAY AND WINDS BECOME NORTH BEHIND THE FRONT. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
330 PM CDT TUE MAY 5 2015 .SHORT TERM /TONIGHT/... ISSUED AT 330 PM CDT TUE MAY 5 2015 THE FRONTAL BOUNDARY REMAINS DRAPED ACROSS CENTRAL IOWA AND HAS NOT MOVED MUCH AT ALL TODAY. IT MADE A VERY SLOW PROGRESSION NORTHWARD AND CURRENTLY SITS JUST SOUTH OF HIGHWAY 20...VERSUS INTERSTATE 80 THIS MORNING. PRECIPITATION FROM EARLIER THIS MORNING FADED AS IT TREKKED NORTHWARD AND AWAY FROM WHAT LITTLE LIFT...MAINLY WAA OVER THE BOUNDARY...REMAINED. CLOUD COVER THAT LINGERED WELL INTO THIS AFTERNOON ACROSS SOUTHERN IOWA PREVENTED SBCAPE VALUES FROM SOARING...BUT HAVE REBOUNDED TO 1500-2000 J/KG WITH NIL CIN ACROSS CENTRAL AND SOUTHERN IOWA. AREAS THAT SAW SUNSHINE WILL LIKELY REACH THEIR CONVECTIVE TEMPS...GENERALLY IN THE UPPER 70S...AND IS BEING REALIZED NOW AS SOME WEAK CONVECTION IS CURRENTLY FIRING UP IN SOUTH CENTRAL IOWA AND WEST OF FORT DODGE. WEAK SHEAR...GENERALLY 20KTS OR LESS...AND NO CAP WILL RESULT IN NUMEROUS PULSE STORMS THAT WILL LIMIT SEVERE POTENTIAL AS THEY FIGHT FOR ENERGY. THE HRRR APPEARS TO HAVE THE BEST HANDLE ON THE SITUATION ON CURRENT CONVECTION AND HAS ALL OF IT GONE BY 03Z WITH THE LACK OF ANY SIGNIFICANT LIFTING MECHANISM OVER NIGHT. TEMPERATURES STRUGGLED TO REACH DAYTIME HIGHS WITH THICK...AND GENERALLY LOW...CLOUDS OVER MUCH OF NORTHERN IOWA. AS A RESULT MANY LOCATIONS STILL SIT IN THE UPPER 50S. WITH THAT IN MIND...HAVE DROPPED LOWS ONLY A COUPLE OF DEGREES SINCE DEWPOINTS WILL REMAIN FAIRLY HIGH AND STOP ANY CRASHING TEMPS. FOG MAY BE OF CONCERN ACROSS THE NORTH AS WELL...BUT MAY BE LIMITED WITH WINDS AROUND 10KTS. SITES THAT SEE WINDS DROP A BIT MAY SEE PERIODS OF FOG. .LONG TERM /WEDNESDAY THROUGH TUESDAY/... ISSUED AT 330 PM CDT TUE MAY 5 2015 GENERALLY SOUTHWESTERLY 500 MB FLOW ACROSS IOWA AND THE MIDWEST WILL RESULT IN AN ACTIVE AND FAIRLY WET WEATHER PATTERN THROUGH THE WEEKEND. THIS PATTERN WILL BE PUNCTUATED BY TWO FAIRLY ROBUST LOW PRESSURE SYSTEMS AND AN INTERMEDIARY PERIOD OF SUBTLE SHORTWAVES MOVING THROUGH THE AFOREMENTIONED SOUTHWESTERLY FLOW. THE FIRST BIG SYSTEM IS CURRENTLY TRACKING ACROSS THE SOUTHERN ROCKIES IN THE FORM OF A DEEP OPEN WAVE...AND WILL MOVE UP OVER OUR REGION ON WEDNESDAY AND WEDNESDAY NIGHT. MEANWHILE A LARGE CLOSED 500 MB LOW CURRENTLY MOVING ASHORE OVER WASHINGTON/BRITISH COLUMBIA WILL DIVE SOUTHWARD ALONG THE PACIFIC U.S. COAST...REACHING NORTHERN CALIFORNIA BY LATE WEDNESDAY NIGHT. THEREAFTER...AS THE FIRST SYSTEM DEPARTS QUICKLY TO OUR NORTHEAST AND THE SECOND SYSTEM DIGS IN AND DEEPENS OVER THE SOUTHWEST U.S. IT WILL MAINTAIN SOUTHWESTERLY FLOW OVER IOWA...THROUGH WHICH SUBTLE SHORTWAVES WILL MOVE AT THE END OF THIS WEEK. FINALLY...THE LARGE SOUTHWEST U.S. LOW WILL EJECT UP ACROSS THE MIDWEST SOMETIME AROUND SUNDAY. AS THE LEADING LOW PRESSURE TROUGH MOVES UP INTO THE REGION ON WEDNESDAY IT WILL PUSH A LARGE REGION OF WARM AIR AND THETA E ADVECTION UP ACROSS IOWA. WITHIN THIS REGION WIDESPREAD THUNDERSTORMS SHOULD DEVELOP OVER NEBRASKA AND KANSAS TONIGHT...THEN SLOWLY FADE AS THEY TRANSLATE ACROSS OUR FORECAST AREA DURING THE DAY WEDNESDAY. WILL MAINTAIN LIKELY POPS FOR MOST OF THE DAY...HOWEVER...CONFIDENCE BY WEDNESDAY AFTERNOON IS NOT HIGH AS IT APPEARS THAT IN WAKE OF THE INITIAL BAND OF WARM AIR ADVECTION THERE MAY BE LITTLE TO FORCE TRAILING CONVECTION AND WE COULD SEE A LULL SIMILAR TO TODAY. IN ANY EVENT...WHILE THERE IS SOME MARGINAL INSTABILITY AND DECENT DEEP LAYER SHEAR...NEARLY UNIFORM LOW LEVEL WINDS AND A LACK OF ANY KIND OF FOCUS MECHANISM LEAD TO A LOW RISK OF SEVERE WEATHER WHICH IS WELL OUTLINED BY SPC. ON WEDNESDAY NIGHT ANOTHER EXPANSION OF THUNDERSTORM COVERAGE WILL LIKELY OCCUR WITH THE NOCTURNAL LOW LEVEL JET ON THE EASTERN FLANK OF THE UPPER LOW PRESSURE SYSTEM...BUT THIS ACTIVITY WILL MOSTLY BE TO OUR WEST ACROSS NEBRASKA...SOUTH DAKOTA AND NORTHWESTERN IOWA AND ONCE AGAIN WITH A LOW SEVERE WEATHER THREAT IN OUR AREA. FORECAST POPS HAVE BEEN TRENDED TOWARD THIS DIRECTION AND TIMING. POTENTIALLY THE MOST ACTIVE PERIOD FOR OUR AREA WILL COME ON THURSDAY. IT APPEARS THAT ONE OR TWO SHORTWAVES MOVING OVERHEAD WILL PUSH A SYNOPTIC SURFACE TROUGH SLOWLY ACROSS OUR AREA ON THURSDAY NIGHT. AHEAD OF THIS TROUGH...AT PEAK HEATING TIME LATE THURSDAY AFTERNOON AND EVENING PROGNOSTIC MODELS UNANIMOUSLY DEPICT A SWATH OF STRONG INSTABILITY DEVELOPING AHEAD OF THE BOUNDARY...THOUGH THIS COULD BE TEMPERED BY DEBRIS FROM EARLY MORNING CONVECTION. WHILE UPPER LEVEL FORCING IS SOMEWHAT LESS IMPRESSIVE DURING THIS TIME...DEEP SHEAR IN THE 25 TO 35 KT RANGE COUPLED WITH SURFACE CAPE APPROACHING 3000 J/KG WOULD CERTAINLY INDICATE A SEVERE WEATHER THREAT. THIS WILL BEAR WATCHING AS WE PROGRESS THROUGH THE WORK WEEK. THE FORECAST FROM LATE THURSDAY NIGHT THROUGH SATURDAY IS DEPENDENT ON HOW FAR SOUTHEAST THE ABOVE DISCUSSED SURFACE TROUGH CAN PROGRESS. IT WILL LIKELY STALL SOMEWHERE OVER SOUTHEASTERN IOWA OR MISSOURI/ILLINOIS...WITH SUBSEQUENT SHORTWAVES MOVING OVERHEAD AND KICKING OFF ONE OR MORE ROUNDS OF THUNDERSTORMS ALONG AND NORTHWEST OF THE FRONTAL ZONE. HOWEVER...IT IS UNCLEAR HOW FAR SOUTHEAST OF OUR AREA THE BOUNDARY WILL LIE AND THUS HOW FAR INTO OUR AREA THESE STORMS MAY PENETRATE. THERE IS LITTLE TO NO MODEL CONSISTENCY IN THIS AREA...AND FOR NOW HAVE STUCK TO CHANCE POPS ACROSS OUR SOUTHEASTERN AREAS DEPICTING A ROUGH CONSENSUS APPROACH. IN ANY EVENT...THE SEVERE WEATHER THREAT DURING THIS TIME WILL BE LOW ALTHOUGH THERE IS SOME POTENTIAL FOR HEAVY RAIN AS STORMS MAY TRAIN ALONG THE FRONTAL ZONE. FINALLY...THE SECOND AND STRONGER LOW PRESSURE SYSTEM DISCUSSED EARLIER WILL MAKE FOR AN ACTIVE PERIOD WITH SEVERAL ROUNDS OF THUNDERSTORMS BETWEEN SATURDAY NIGHT AND SUNDAY NIGHT. GIVEN THE ENERGETIC NATURE OF THE SYSTEM THERE WILL AGAIN BE A POTENTIAL FOR SEVERE WEATHER...HOWEVER AT THIS RANGE THE CRITICAL DETAILS OF TRACK AND TIMING AND THUS THE REGION OF MAXIMUM SEVERE WEATHER POTENTIAL REMAIN VERY UNCLEAR. IN ANY EVENT...IN WAKE OF THIS WEEKEND SYSTEM IT APPEARS THAT A BRIEF RESPITE OF COOL AND QUIET WEATHER MAY BE IN STORE FOR EARLY NEXT WEEK. && .AVIATION...05/18Z ISSUED AT 1238 PM CDT TUE MAY 5 2015 FRONTAL BOUNDARY IS DRAPED ACROSS THE THE STATE...LOCATED JUST SOUTH OF FOD AND ALO SITES. WITH ALO AND FOD JUST NORTH OF THE BOUNDARY...CIGS AND VSBY HAVE BEEN IN IFR AND MVFR MOST OF THE DAY FROM. IMPROVEMENT AT THOSE SITES WILL BE SLOW AS CIGS GRADUALLY MOVE TOWARDS VFR THIS EVENING AND OVERNIGHT AS THE FRONT SLOWLY SHIFTS NORTH. DSM AND OTM SHOULD REMAIN VFR THROUGH MUCH OF THE TAF PERIOD...WITH CHANCES OF FOG OVERNIGHT. THE NORTHERN SITES MAY SEE PRECIPITATION THIS EVENING...INCLUDING OCCASIONAL THUNDER...BUT NONE OF THE MODELS ARE IN GREAT AGREEMENT ON TIMING AND INTENSITY...SO MENTIONED ONLY VCSH FOR NOW AT ALO AND MCW. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...CURTIS LONG TERM...LEE AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
447 PM EDT TUE MAY 5 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN WELL OFF THE SOUTHEAST AND MID ATLANTIC COAST THROUGH TONIGHT...BRINGING VERY WARM AND MAINLY DRY CONDITIONS TO THE LOCAL AREA. A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH TONIGHT...THEN DROPS INTO VIRGINIA LATE WEDNESDAY INTO EARLY THURSDAY...BEFORE DISSIPATING. LOW PRESSURE WILL SPIN OFF OR NEAR THE SOUTHEAST COAST THURSDAY INTO SATURDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LATEST ANALYSIS REVEALS SFC HIGH PRESSURE CENTERED WELL OFFSHORE OF THE VA/NC COAST, EXTENDING BACK ACROSS EASTERN NC. ~1006 MB LOW PRESSURE WAS ANALYZED ACROSS NEWFOUNDLAND, WITH SFC COLD FRONT SNAKING BACK ACROSS NEW ENGLAND INTO NE PA/NW NJ AND THE EASTERN GRT LAKES. A PRE-FRONTAL SFC TROUGH EXTENDS SW FROM SE PA INTO SRN MD AND NORTHERN VA. HAVE NOTED SOME INCREASING CU OVER THE PAST FEW HOURS ALONG THE BLUE RIDGE AND EXPECT TO SEE A BIT MORE TO DEVELOP ACROSS WESTERN SECTIONS OF THE LOCAL AREA ALONG THE TROUGH BY OVER THE NEXT FEW HOURS. DO HAVE SOME LOW CHANCES FOR SHOWERS/TSTMS ACRS THE FAR N/NW LATE THIS AFTN/EVENING. EXPECT ANY SHOWERS TO BE SHORT LIVED OWING TO FLAT/QUASI-ZONAL FLOW ALOFT AND SHOULD THEREFORE ALLOW LIMITED CONVECTIVE DEVELOPMENT AND WILL YIELD A VERY SLOW SOUTHWARD PROGRESSION OF THE FRONT THROUGH TONIGHT AND INTO TOMORROW. BY TONIGHT, SHORTWAVE ENERGY NOTED ON IR SAT ACRS THE LWR GRT LAKES WILL DAMPEN AS IT DIVES SOUTHEAST ACROSS THE NORTHERN MID- ATLANTIC. RESULTANT UPPER FLOW SHIFTS TO THE WNW, AND WOULD ALLOW ANY LIGNERING SHOWERS AND STORMS TO CROSS A BIT FARTHER TO THE SOUTH. GIVEN THE LIMITED ACTIVITY THUS FAR, AND W/ HRRR NOT OVERLY EXCITED ABOUT ACTIVITY TONIGHT, WILL HANG ON TO A 30-40% RAIN CHANCE FOR SOME SCT SHRAS THIS EVENING ACROSS THE WEST, AND LATE TONIGHT/OVERNIGHT FOR THE EASTERN SHORE. FARTHER S-SE, EXPECT DRY CONDS TO CONTINUE UNDER A PARTLY CLOUDY SKY. LOWS TONIGHT IN THE UPPER 50S TO LWR 60S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... HAVE LINGERED A SLIGHT CHC FOR LINGERING SHOWERS JUST AFTER SUNSET TOMORROW MORNING...W/AREA OF WEAK LIFT SLIDING ESE ALONG AND AHEAD OF THE BACKDOOR FRONT COINCIDENT WITH PLENTY OF LINGERING LLVL MOISTURE. ANY SHOWERS WOULD BE BRIEF AND WIDELY SCT AT MOST. OTHERWISE...DRY IN THE MORNING FOR MOST. EARLY SUN WILL GIVE WAY TO INCREASING AFTN CLOUDS ACROSS CENTRAL/SOUTHERN ZONES. STRONG HEATING AND THE ARRIVAL OF THE FRONT WILL LIKELY PROVIDE THE TRIGGER FOR SOME SCT AFTN SHRAS/THUNDERSTORMS...MAINLY OVR WRN AND NRN COUNTIES LATE IN THE AFTN INTO WED NIGHT. FOR TEMPS, STILL ON THE WARM SIDE OF THE GUIDANCE ENVELOPE IN EXPECTATION OF A SLOWER FRONTAL PROGRESSION...RESULTING IN A PARTLY TO MOSTLY SUNNY SKY EARLY AND HIGHS FM 80-85 WEST OF THE BAY...TO THE 70S ON THE ERN SHORE. FRONT BECOMES VERY DIFFUSE TOMORROW NIGHT AND WASHES OUT BY THE TIME IT REACHES THE VA/NC BORDER. MEANWHILE, SFC LOW PRES WILL BEGIN TO TAKE SHAPE AND CLOSE OFF ALONG THE EAST COAST OF FLORIDA/SE GA WED AFTN/NIGHT. WEAK SFC RIDGING WILL RE-ESTABLISH ITSELF OVERHEAD AND ALLOW FOR A DRY OVERNIGHT WED NIGHT INTO THU MORNING. HOWEVER, EXPECT A GOOD AMOUNT OF LOW TO MID LEVEL CLOUD TO LINGER OVERNIGHT INTO THU MORNING ALONG AND BEHIND THE FRONT ACROSS NORTHERN HALF OF THE AREA. GENERALLY PARTLY SUNNY FARTHER SOUTH A 20-30% CHC FOR A SHOWER OR TSTM, AGAIN MAINLY IN THE AFTN/EARLY EVENING. E-NE WINDS WILL RESULT IN HI TEMPS RANGING THRU THE 70S TO NEAR 80 SW TO THE UPPER 60S/LWR 70S ERN SHORE. STILL MONITORING THE PROGRESS OF AFOREMENTIONED LOW ALONG THE SE COAST. MODELS STILL HAVING TROUBLE RESOLVING THIS SYSTEM...WHICH IS CASTING A BIT OF LOWER CONFIDENCE ON THE HANDLING OF THIS SYSTEM. THE 12Z/5 GFS CONTINUES TO BRING THE SFC LOW INLAND OF THE SC/NC COAST...WITH THE 12Z/NAM NOW IN CLOSE ENOUGH TO COVER THU NIGHT AND FRIDAY. ITS SOLUTION IS SLIGHTLY FASTER THAN THE GFS AND TAKES THE SURFACE LOW INLAND ACROSS EXTREME NE GA/COASTAL SC BY EARLY FRIDAY MORNING. FOR ITS PART, THE OPERATIONAL ECMWF REMAINS OFFSHORE, BUT HAS TRENDED TOWARD THE GFS IN MOVING A BIT CLOSER TO THE COAST WITH THE SFC LOW...AND EVEN KEEPS THE LOW NEARLY STATIONARY ALONG THE CAROLINA COAST FOR FRIDAY AND THROUGH THE WEEKEND. HAVE GONE WITH A GFS WEIGHTED GFS/ECMWF BLEND FOR FRIDAY UNTIL MODELS COME INTO A BIT CLOSER AGREEMENT. EITEHR WAY, EXPECT FRIDAY TO BE PREDOMINATELY DRY ACROSS THE LOCAL AREA, BUT SHOULD SEE SOME (MAINLY) DIURNALLY DRIVEN SCT SHOWERS/TSTMS POSSIBLE OVER THE SOUTHERN HALF OF THE AREA (BEST CHC SOUTH OF THE BORDER INTO NC). HIGHS 80-85 INLAND, COOLER U60S TO M70S ALONG THE COAST IN CONTINUED ONSHORE FLOW. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... THE EXTENDED PERIOD WILL BEGIN WITH LO PRES SPINNING JUST OFF OR ALNG THE SE OR NC CST FRI NGT INTO MON MORNG. THEN...MODELS SHOW THE LO WEAKENING AND GETTING PUSHED NNE ALNG OR JUST OFF THE VA CST MON NGT INTO TUE MORNG...AS A COLD FRONT APPROACHES FM THE W. THAT FRONT WILL THEN MOVE ACRS THE AREA TUE INTO TUE NGT. WILL HAVE 20%-30% POPS FOR SHOWERS OR TSTMS OVR MUCH OF THE REGION FRI NGT THRU MON NGT...DUE TO MOISTURE/LIFT FM THE LO PRES AREA. THEN...HAVE 30%-40% POPS FOR TUE/TUE NGT ASSOCIATED WITH THE COLD FRONT. TEMPS WILL BE ABV NORMAL THRU THE PERIOD...WITH HIGHS RANGING FM THE MID 70S TO MID 80S. LOWS WILL RANGE FM THE UPR 50S TO MID 60S. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... HIGH PRESSURE GENERALLY IN CONTROL OVER THE MID-ATLANTIC THIS AFTERNOON WITH A WEAK SURFACE TROUGH TO THE NORTH OF THE AKQ CWA. A COLD FRONT REMAINS OVER SOUTHERN NY STRETCHING WEST INTO PA AND OH. SWLY WINDS 10-15 KT CONTINUE WITH A FEW AFTERNOON GUSTS AROUND 20 KT. SHOWERS/THUNDERSTORMS DEVELOP ALONG THE FRONT LATE TODAY...DROPPING SWD TOWARD THE NRN LOCAL AREA TONIGHT. WILL LIKELY SEE AN INCREASE IN MID-HIGH CLOUDS EARLY TONIGHT AT KSBY AND KRIC...WITH SHOWERS (POSSIBLY A THUNDERSTORM) POSSIBLE LATE TONIGHT AT KSBY. OUTLOOK: THERE WILL BE A DAILY CHANCE FOR MAINLY AFTN AND EARLY EVENING SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH SATURDAY. THEY ARE NOT EXPECTED TO BE WIDESPREAD. OTHERWISE MAINLY VFR CONDITIONS ARE EXPECTED DURING THE PERIOD. LATE IN THE WEEK...PATCHY FOG WILL BE PSBL AROUND SUNRISE. && .MARINE... NO HEADLINES IN THE SHORT TERM TNGT THRU THU. HI PRES WILL SLIDE FARTHER OUT TO SEA TNGT THRU WED. MODELS STILL SHOW LO PRES SPINNING JUST OFF OR NEAR THE SE CST THU INTO SUN. EXPECT SSW WINDS 15 KT OR LESS TNGT INTO WED NGT...THEN E OR SE WINDS 5 TO 15 KT THU INTO SUN. WAVES WILL BE 1 TO 2 FT...AND SEAS WILL BE 2 TO 4 FT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...LKB/MAM LONG TERM...TMG AVIATION...DAP MARINE...TMG
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
335 PM EDT TUE MAY 5 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN WELL OFF THE SOUTHEAST AND MID ATLANTIC COAST THROUGH TONIGHT...BRINGING VERY WARM AND MAINLY DRY CONDITIONS TO THE LOCAL AREA. A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH TONIGHT...THEN DROPS INTO VIRGINIA LATE WEDNESDAY INTO EARLY THURSDAY...BEFORE DISSIPATING. LOW PRESSURE WILL SPIN OFF OR NEAR THE SOUTHEAST COAST THURSDAY INTO SATURDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LATEST ANALYSIS REVEALS SFC HIGH PRESSURE CENTERED WELL OFFSHORE OF THE VA/NC COAST, EXTENDING BACK ACROSS EASTERN NC. ~1006 MB LOW PRESSURE WAS ANALYZED ACROSS NEWFOUNDLAND, WITH SFC COLD FRONT SNAKING BACK ACROSS NEW ENGLAND INTO NE PA/NW NJ AND THE EASTERN GRT LAKES. A PRE-FRONTAL SFC TROUGH EXTENDS SW FROM SE PA INTO SRN MD AND NORTHERN VA. HAVE NOTED SOME INCREASING CU OVER THE PAST FEW HOURS ALONG THE BLUE RIDGE AND EXPECT TO SEE A BIT MORE TO DEVELOP ACROSS WESTERN SECTIONS OF THE LOCAL AREA ALONG THE TROUGH BY OVER THE NEXT FEW HOURS. DO HAVE SOME LOW CHANCES FOR SHOWERS/TSTMS ACRS THE FAR N/NW LATE THIS AFTN/EVENING. EXPECT ANY SHOWERS TO BE SHORT LIVED OWING TO FLAT/QUASI-ZONAL FLOW ALOFT AND SHOULD THEREFORE ALLOW LIMITED CONVECTIVE DEVELOPMENT AND WILL YIELD A VERY SLOW SOUTHWARD PROGRESSION OF THE FRONT THROUGH TONIGHT AND INTO TOMORROW. BY TONIGHT, SHORTWAVE ENERGY NOTED ON IR SAT ACRS THE LWR GRT LAKES WILL DAMPEN AS IT DIVES SOUTHEAST ACROSS THE NORTHERN MID- ATLANTIC. RESULTANT UPPER FLOW SHIFTS TO THE WNW, AND WOULD ALLOW ANY LIGNERING SHOWERS AND STORMS TO CROSS A BIT FARTHER TO THE SOUTH. GIVEN THE LIMITED ACTIVITY THUS FAR, AND W/ HRRR NOT OVERLY EXCITED ABOUT ACTIVITY TONIGHT, WILL HANG ON TO A 30-40% RAIN CHANCE FOR SOME SCT SHRAS THIS EVENING ACROSS THE WEST, AND LATE TONIGHT/OVERNIGHT FOR THE EASTERN SHORE. FARTHER S-SE, EXPECT DRY CONDS TO CONTINUE UNDER A PARTLY CLOUDY SKY. LOWS TONIGHT IN THE UPPER 50S TO LWR 60S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... HAVE LINGERED A SLIGHT CHC FOR LINGERING SHOWERS JUST AFTER SUNSET TOMORROW MORNING...W/AREA OF WEAK LIFT SLIDING ESE ALONG AND AHEAD OF THE BACKDOOR FRONT COINCIDENT WITH PLENTY OF LINGERING LLVL MOISTURE. ANY SHOWERS WOULD BE BRIEF AND WIDELY SCT AT MOST. OTHERWISE...DRY IN THE MORNING FOR MOST. EARLY SUN WILL GIVE WAY TO INCREASING AFTN CLOUDS ACROSS CENTRAL/SOUTHERN ZONES. STRONG HEATING AND THE ARRIVAL OF THE FRONT WILL LIKELY PROVIDE THE TRIGGER FOR SOME SCT AFTN SHRAS/THUNDERSTORMS...MAINLY OVR WRN AND NRN COUNTIES LATE IN THE AFTN INTO WED NIGHT. FOR TEMPS, STILL ON THE WARM SIDE OF THE GUIDANCE ENVELOPE IN EXPECTATION OF A SLOWER FRONTAL PROGRESSION...RESULTING IN A PARTLY TO MOSTLY SUNNY SKY EARLY AND HIGHS FM 80-85 WEST OF THE BAY...TO THE 70S ON THE ERN SHORE. FRONT BECOMES VERY DIFFUSE TOMORROW NIGHT AND WASHES OUT BY THE TIME IT REACHES THE VA/NC BORDER. MEANWHILE, SFC LOW PRES WILL BEGIN TO TAKE SHAPE AND CLOSE OFF ALONG THE EAST COAST OF FLORIDA/SE GA WED AFTN/NIGHT. WEAK SFC RIDGING WILL RE-ESTABLISH ITSELF OVERHEAD AND ALLOW FOR A DRY OVERNIGHT WED NIGHT INTO THU MORNING. HOWEVER, EXPECT A GOOD AMOUNT OF LOW TO MID LEVEL CLOUD TO LINGER OVERNIGHT INTO THU MORNING ALONG AND BEHIND THE FRONT ACROSS NORTHERN HALF OF THE AREA. GENERALLY PARTLY SUNNY FARTHER SOUTH A 20-30% CHC FOR A SHOWER OR TSTM, AGAIN MAINLY IN THE AFTN/EARLY EVENING. E-NE WINDS WILL RESULT IN HI TEMPS RANGING THRU THE 70S TO NEAR 80 SW TO THE UPPER 60S/LWR 70S ERN SHORE. STILL MONITORING THE PROGRESS OF AFOREMENTIONED LOW ALONG THE SE COAST. MODELS STILL HAVING TROUBLE RESOLVING THIS SYSTEM...WHICH IS CASTING A BIT OF LOWER CONFIDENCE ON THE HANDLING OF THIS SYSTEM. THE 12Z/5 GFS CONTINUES TO BRING THE SFC LOW INLAND OF THE SC/NC COAST...WITH THE 12Z/NAM NOW IN CLOSE ENOUGH TO COVER THU NIGHT AND FRIDAY. ITS SOLUTION IS SLIGHTLY FASTER THAN THE GFS AND TAKES THE SURFACE LOW INLAND ACROSS EXTREME NE GA/COASTAL SC BY EARLY FRIDAY MORNING. FOR ITS PART, THE OPERATIONAL ECMWF REMAINS OFFSHORE, BUT HAS TRENDED TOWARD THE GFS IN MOVING A BIT CLOSER TO THE COAST WITH THE SFC LOW...AND EVEN KEEPS THE LOW NEARLY STATIONARY ALONG THE CAROLINA COAST FOR FRIDAY AND THROUGH THE WEEKEND. HAVE GONE WITH A GFS WEIGHTED GFS/ECMWF BLEND FOR FRIDAY UNTIL MODELS COME INTO A BIT CLOSER AGREEMENT. EITEHR WAY, EXPECT FRIDAY TO BE PREDOMINATELY DRY ACROSS THE LOCAL AREA, BUT SHOULD SEE SOME (MAINLY) DIURNALLY DRIVEN SCT SHOWERS/TSTMS POSSIBLE OVER THE SOUTHERN HALF OF THE AREA (BEST CHC SOUTH OF THE BORDER INTO NC). HIGHS 80-85 INLAND, COOLER U60S TO M70S ALONG THE COAST IN CONTINUED ONSHORE FLOW. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MEDIUM RANGE PERIOD HIGHLY DEPENDENT PERSISTENT UPPER RIDGE OVER THE EAST, AS WELL AS THE DEVELOPMENT AND EVENTUAL PROGRESS OF EXPECTED DEVELOPMENT OF AN AREA OF LOW PRESSURE OFF THE EAST COAST OF FLORIDA. MODELS ARE IN GENERAL AGREEMENT OF THE DEVELOPMENT AND INITIAL SLOW DRIFT NORTHWARD ON WEDNESDAY. THE HURRICANE CENTER IS CONTINUING TO MONITOR THIS FEATURE FOR POTENTIAL SUBTROPICAL DEVELOPMENT. SFC RIDGING TO THE NORTH AND W-NW FLOW ALOFT SHOULD FORCE THE LOW TO MEANDER AROUND A POSITION ALONG/JUST OFF THE SOUTHEAST COAST THROUGH THE WEEKEND. THE GEFS AND EURO ENSEMBLES BOTH CONTINUE TO TAKE THE LOW INLAND ALONG THE SC/GA COAST, AS DOES THE NEW 12Z/04 GFS. THE OPERATIONAL EUROPEAN, MEANWHILE CONTINUES TO KEEP THE SYSTEM OFFSHORE. A SOLUTION TOWARDS THE GFS REMAINS THE HPC PREFERENCE, AND HV EDGED THE FORECAST IN THIS DIRECTION. THIS SCENARIO WOULD YIELD SLIGHT CHC TO LOW CHC POP FOR MAINLY DIURNALLY DRIVEN SHOWERS/T-STORMS AT MOST ACROSS OUR AREA. LOWEST CHANCES WILL BE ACROSS THE NORTH WITH SFC RIDGING IN PLACE NORTH OF THE AREA. OTHER HEADLINE FOR THE PERIOD WILL BE THE WARMER TEMPERATURES. E-SE FLOW WILL BRING A MODEST INCREASE IN HUMIDITY, AND INCREASING LOW LEVEL THICKNESSES FAVOR WARM HIGHS IN THE 80S UNDER A PARTLY TO MOSTLY SUNNY SKY. EARLY MORNING LOWS LOOK TO REMAIN WELL INTO THE 50S TO MID 60S LATE WEEK INTO EARLY NEXT WEEK. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... HIGH PRESSURE GENERALLY IN CONTROL OVER THE MID-ATLANTIC THIS AFTERNOON WITH A WEAK SURFACE TROUGH TO THE NORTH OF THE AKQ CWA. A COLD FRONT REMAINS OVER SOUTHERN NY STRETCHING WEST INTO PA AND OH. SWLY WINDS 10-15 KT CONTINUE WITH A FEW AFTERNOON GUSTS AROUND 20 KT. SHOWERS/THUNDERSTORMS DEVELOP ALONG THE FRONT LATE TODAY...DROPPING SWD TOWARD THE NRN LOCAL AREA TONIGHT. WILL LIKELY SEE AN INCREASE IN MID-HIGH CLOUDS EARLY TONIGHT AT KSBY AND KRIC...WITH SHOWERS (POSSIBLY A THUNDERSTORM) POSSIBLE LATE TONIGHT AT KSBY. OUTLOOK: THERE WILL BE A DAILY CHANCE FOR MAINLY AFTN AND EARLY EVENING SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH SATURDAY. THEY ARE NOT EXPECTED TO BE WIDESPREAD. OTHERWISE MAINLY VFR CONDITIONS ARE EXPECTED DURING THE PERIOD. LATE IN THE WEEK...PATCHY FOG WILL BE PSBL AROUND SUNRISE. && .MARINE... LATEST WEATHER ANALYSIS ACROSS THE WATERS DEPICTS HIGH PRESSURE CENTERED ROUGHLY 500 NM OFF THE MID ATLANTIC COAST AND LOW PRESSURE OVER NEWFOUNDLAND. AN ATTENDANT COLD FRONT EXTENDS FROM THE SFC LOW SWWD INTO NEW ENGLAND AND THE OH VALLEY. GRADIENT HAS RESULTED IN A PERIOD OF MARGINAL SCA CONDITIONS OVER THE BAY AND LOWER JAMES RIVER EARLY THIS MORNING...WITH OCCASIONAL GUSTS 20-25 KT. HAVE OPTED TO ISSUE SCA HEADLINES THRU 7 AM AS GRADIENT EXPECTED TO RELAX AND LOW LEVELS STABILIZE. WAVES GENERALLY 2-3 FT AND SEAS AROUND 3 FT. HIGH PRESSURE PUSHES FARTHER OFFSHORE TODAY AS THE COLD FRONT SLOWLY APPROACHES FROM THE NORTH. S-SW WINDS GENERALLY 10-15 KT TODAY...WITH OCCASIONAL GUSTS TO 20 KT IN THE COASTAL WATERS. SLIGHT UPTICK IN WINDS POSSIBLE AGAIN TONIGHT...BUT NOT AS STRONG AS EARLY THIS MORNING AS THE WINDS ALOFT ARE PROGGED TO BE WEAKER. THE COLD FRONT IS PROGGED TO REACH THE NRN WATERS LATE WEDS...DROPPING ACROSS THE WATERS WEDS NIGHT INTO THURS. THE FRONT THEN WASHES OUT OVER THE REGION THURS AS LOW PRESSURE LOCATES OFF THE SE COAST. FLOW BEHIND THE FRONT BECOMES NELY...REMAINING AOB 15 KT. SEAS ONLY PROGGED TO BUILD TO 3-4 FT WEDS NIGHT-THURS. UNCERTAINTY STILL EXISTS IN THE EXACT TRACK AND STRENGTH OF THE COASTAL LOW LATE IN THE WEEK. ATTM...MODELS KEEP THE LOW OFF THE SE COAST INTO THE WEEKEND. THIS TRACK STAYS TOO FAR SOUTH TO BRING ANY SIGNIFICANT INCREASE IN SEAS AND WINDS TO THE LOCAL AREA. OTHERWISE...HIGH PRESSURE REMAINS OVER THE LOCAL WATERS THRU THE WEEKEND WITH SE WINDS GENERALLY AOB 15 KT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...LKB/MAM LONG TERM...MAM AVIATION...SAM/DAP MARINE...MAM/SAM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
154 PM EDT TUE MAY 5 2015 .AVIATION... THE MATURE MCS AND INITIAL SURGE OF DEEP MOISTURE IS CURRENTLY TRACKING THROUGH SOUTHEASTERN MICHIGAN THIS AFTERNOON. LATEST DATA SUGGESTS A CONTINUED POTENTIAL FOR SHOWERS AND THUNDERSTORMS OVER MUCH OF THE AREA THROUGH AT LEAST THE EARLY EVENING HOURS. A DEVELOPING WARM FRONT IS THEN EXPECTED TO SLOWLY ORGANIZE OVER SECTIONS OF SEMICH TONIGHT. UNCERTAINTY EXISTS TO EXACTLY WHERE THIS BOUNDARY WILL STALL OUT FOR A TIME...BUT LATEST INDICATIONS ARE SUGGESTING THE NORTHERN DETROIT METRO AREA THROUGH THE I 69 CORRDOR. IT IS ALONG THIS BOUNDARY THAT A POTENTIAL EXISTS FOR CONTINUED...LONG DURATION RAIN OVERNIGHT. FOCUSED THIS RAIN MENTION AT THE KPTK/KFNT FOR THIS TAF ISSUANCE...WILL CONTINUE TO MONITOR THE NEED FOR THE SOUTHERN TAF SITES. THE OTHER IMPORTANT ISSUE FOR TONIGHT WILL BE THE POTENTIAL FOR IFR/LIFR CIGS ALONG AND TO THE SOUTH OF THE DEVELOPING FRONTAL BOUNDARY. WENT MORE AGGRESSIVE WITH IFR/LIFR CIGS SOUTH. FOR DTW...RAIN POTENTIAL WILL NOW SHIFT TO MORE SHOWER CHARACTER AS THE INITIAL MATURE MCS SHIFTS NORTHWARD THROUGH THE CWA. WILL NEED TO MONITOR PORTIONS OF NORTHERN ILLINOIS/INDIANA WHERE ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT IS FORECASTED TO TAKE PLACE. IT REMAINS POSSIBLE THIS ACTIVITY WHILE MOVING EASTWARD COULD IMPACT PORTIONS OF FAR SOUTHERN MICHIGAN...INCLUDING THE METRO TERMINAL. OTHERWISE TONIGHT...EXPECTATIONS AT THIS TIME ARE FOR THE WARM FRONT TO SET UP NORTH OF THE TERMINAL...FOCUSING BEST LONG DURATION RAINS CHANCES NORTH. LIFR CIGS TONIGHT AND TOMORROW MORNING. //DTW THRESHOLD PROBABILITIES... * HIGH FOR CEILING BELOW 5000 FT TONIGHT. * LOW FOR THUNDERSTORMS THIS EVENING AND TONIGHT * LOW FOR CIGS TO FALL BELOW 200 FEET. && .PREV DISCUSSION...ISSUED 1034 AM EDT TUE MAY 5 2015 UPDATE... THE DETAILED FORECAST REASONING PROVIDED IN THE EARLY MORNING DISCUSSION WAS WELL DONE AND REMAINS VALID. A MATURE MCS AND COMPLEX OF SHORTWAVE ENERGY SUPPORTED BY RIGHT ENTRANCE REGION DYNAMICS ALOFT IS CURRENTLY LIFTING INTO SOUTHEASTERN MICHIGAN THIS MORNING. SURFACE PRECIPITATION REPORTS SUPPORT LIGHT TO MODERATE RAIN OCCURRING WITHIN THE FORWARD...WARM AIR ADVECTION QUADRANTS OF THE MCS. WITH THE RAIN MOVING IN...SOUTHEASTERN MICHIGAN CAN EXPECT CATEGORICAL/PERIODS OF RAIN THROUGHOUT THE AFTERNOON HOURS. FORECAST UNCERTAINTY FOR THE SHORT TERM PERIOD CENTERS ON WHEN EXACTLY SYNOPTIC SUPPORT/RAIN WILL END OVER THE AREA. LATEST NAM AND RAP ARE REALLY PAINTING DIFFERENT PICTURES. NAM SUGGESTS SUBSIDENCE IN THE WAKE OF THIS MCS...MAY BRING A QUIET PERIOD EARLY THIS EVENING...WHILE THE RAP DRAGS OUT THE DURATION OF THIS CATEGORICAL RAIN INTO THE EVENING. THERE REMAINS A WINDOW OF OPPORTUNITY FOR SOME THUNDER CHANCES LATE THIS AFTERNOON...POST 20Z. THOSE CHANCES APPEAR TO HINGE ON THE LIKELIHOOD OF THE NAM SOLUTION VERIFYING. NEGLIGIBLE CONVECTIVE INSTABILITY YIELDS NO SUPPORT FOR SEVERE THUNDERSTORM POTENTIAL. PREV DISCUSSION...ISSUED 355 AM EDT TUE MAY 5 2015 SHORT TERM... TODAY AND TONIGHT A WET 24 HOUR PERIOD IS SETTING UP OVER SOUTHERN LOWER MICHIGAN TODAY THROUGH TONIGHT. THE TRI CITIES AND NORTHERN THUMB MAY ESCAPE THE BULK OF THE RAINFALL TODAY BUT THE REST OF SE MICHIGAN STANDS TO PICK UP A PROLONGED PERIOD OF SHOWERS AND THUNDERSTORMS. THE SURFACE FRONT WILL REMAIN SOUTH OF THE OHIO BORDER THROUGH THE PERIOD SO THUNDERSTORMS WILL BE THE ELEVATED VARIETY AND MAINLY CONTRIBUTE TO LOCALLY HEAVY DOWNPOURS. RAINFALL TOTALS LOCALLY AROUND 1 INCH WILL BE POSSIBLE BY SUNRISE WEDNESDAY. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE ALREADY UNDERWAY OVER THE MIDWEST AND WILL SPREAD TO THE NORTH AND EAST DURING THE REST OF THE MORNING. THIS AREA OF CONVECTION ORIGINATED ALONG THE FRONT OVER THE CENTRAL PLAINS DURING PEAK HEATING YESTERDAY AND HAS SINCE GROWN LARGE ENOUGH AND PERSISTENT ENOUGH TO SUPPORT MCV DEVELOPMENT ALOFT AND AN AREA OF SURFACE PRESSURE FALLS OVER IOWA AND MISSOURI. THE WAVE IS JUST STRONG ENOUGH TO SUPPORT A WEAK LOW LEVEL JET FUELING ACTIVITY OVER NORTHERN ILLINOIS WHICH WILL CONTINUE TO DEVELOP INTO SOUTHERN LOWER MICHIGAN AS THE LOW TO MID LEVELS OF THE FRONT STRENGTHEN WITH TIME. CONVECTIVE DEBRIS IN SATELLITE IMAGERY SHOWS THE ENTRANCE REGION OF A 120 KNOT UPPER JET ANALYZED IN MODEL DATA AT 250 MB. THIS FEATURE IS POSITIONED FAVORABLY OVER THE GREAT LAKES TO GENERATE STRONG FRONTOGENESIS THROUGH TODAY WHILE THE LARGE SCALE FRONTAL POSITION REMAINS STATIONARY AND THEN DRIFTS SLOWLY NORTHWARD TONIGHT. CROSS SECTIONS OF MODEL DATA FROM THE POSITION OF THE SURFACE FRONT EXTENDING NORTHWARD TO THE UPPER JET AXIS SHOW THE STEEPEST PORTION OF THE AGEOSTROPHIC CIRCULATION SETTING UP THROUGH CENTRAL SECTIONS OF OUR AREA BY AFTERNOON THROUGH THIS EVENING. DEEP CONVECTIVE INSTABILITY ABOVE THE FRONTAL SURFACE COMBINED WITH PRECIPITABLE WATER RISING TO ABOUT 1.25 INCHES WILL ENSURE WIDESPREAD COVERAGE OF SHOWERS WITH EMBEDDED THUNDERSTORMS. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE DUE TO THE PERSISTENCE OF THIS TEXTBOOK UPPER JET ENHANCED FRONTAL CIRCULATION AND THE CONVECTIVE NATURE OF THE PRECIPITATION PATTERN. SO THEN WHAT COULD GO WRONG IN THIS FORECAST? THE POTENTIAL FOR SURFACE BASED CONVECTION OVER INDIANA AND OHIO...COMBINED WITH THE TENDENCY FOR ELEVATED INSTABILITY TO BECOME LESS EFFECTIVE DURING THE DAY...COULD LEAD TO A WEAKENING TREND IN THE PATTERN OVER SE MICHIGAN DURING THE AFTERNOON INTO THIS EVENING. SHOULD THIS OCCUR...IT WOULD DO MORE TO REDUCE THE POTENTIAL FOR HEAVY RAINFALL IN OUR AREA AND POSSIBLY ALTER THE LOCATION OF THE MOST PERSISTENT SHOWERS AND OVERALL QPF... BUT MOST AREAS WILL SEE A LENGTHY PERIOD OF RAIN AS THE MORNING RAMP UP WOULD CARRY OVER INTO THE AFTERNOON JUST BASED ON INERTIA. PROGRESSION OF THE UPPER LEVEL RIDGE AND THE ENTRANCE REGION OF THE UPPER JET WILL NUDGE THE MID LEVEL FRONTAL ZONE TO THE NORTH AND EAST OVERNIGHT. THIS WILL BRING THE TRI CITIES AND NORTHERN THUMB MORE INTO THE PATTERN OF REMAINING SHOWERS AND WILL BE THE FAVORED LOCATION FOR ANY NOCTURNAL REDEVELOPMENT. THE AXIS OF LIKELY POPS OVER SE MICHIGAN IS PLACED ALONG THE 850 MB THETA-E GRADIENT WHICH IS WELL AGREED UPON BY THE 00Z MODEL CYCLE AND IS THE MOST FAVORED LOCATION FOR RENEWED DEVELOPMENT OF NOCTURNAL ELEVATED INSTABILITY AND SUPPORT FOR SHOWERS THROUGH SUNRISE WEDNESDAY. LONG TERM...WEDNESDAY THROUGH MONDAY SE MICHIGAN WILL RESIDE ALONG THE IMMEDIATE DOWNSTREAM SIDE OF AN ELONGATING UPPER RIDGE ON WEDNESDAY. THE RESULTING WEAKLY SHEARED WEST-NORTHWEST FLOW WILL SUSTAIN A PERTURBED 850-925 MB FRONTAL ZONE ACROSS THE REGION. MODELS TRENDING SLIGHTLY STRONGER WITH THE ASCENT/CONVERGENCE THROUGH THIS LAYER...SUGGESTING THE EXISTING FRONTAL SLOPE WILL POTENTIALLY BE MORE ACTIVE. THIS WILL SUPPORT THE INCLUSION OF A LOWER END POP. GREATER POTENTIAL FOR SHOWER PRODUCTION DURING THE MORNING PERIOD...BEFORE BOTH THE MOISTURE QUALITY AND AVAILABLE FORCING DIMINISHES AS THE INBOUND UPPER RIDGE MAKES BETTER INROADS. SUBSTANTIAL CLOUD COVER WITHIN PERSISTENT LOW LEVEL EASTERLY FLOW WILL CAP THE DIURNAL TEMPERATURE RESPONSE TO SOME DEGREE...REGARDLESS OF SHOWER COVERAGE. ABSENT OF A LARGER AND PERSISTENT COVERAGE OF SHOWERS TO DISRUPT THE HEATING CYCLE... EXISTING THERMAL PROFILE WILL SUPPORT HIGHS GENERALLY WITHIN THE MID AND UPPER 60S RANGE. UPPER RIDGE STEADILY BUILDS INTO LOWER MICHIGAN WEDNESDAY NIGHT... 580 DM AT 500 MB MARKING THE RIDGE AXIS CENTERING OVERHEAD BY EARLY THURSDAY MORNING. THIS PROGRESSION WILL SEND SE MICHIGAN INTO THE WARM SECTOR BY THURSDAY...SOLID DEPTH TO THE EMERGING SOUTHWEST FLOW CONTINUING TO POINT TOWARD HIGHS MAKING A RUN INTO THE LOWER 80S. DRY/STABLE PROFILE STILL INFLUENCED BY EXITING UPPER RIDGING WILL RESULT IN LITTLE MORE THAN A STANDARD DIURNAL CU FIELD. CLOSED LOW CURRENTLY PARKED OVER THE DESERT SOUTHWEST WILL LIFT NORTHEAST THROUGH THE LATTER HALF OF THE WEEK...EVENTUALLY SHEARING OVER THE TOP OF THE UPPER RIDGE STAGNATING ALONG THE EAST COAST. THIS LOWERING HEIGHT FIELD WILL BEGIN TO EASE AN ATTENDANT FRONTAL BOUNDARY EASTWARD WITHIN THE FRIDAY AND SATURDAY WINDOW. GENERAL TIMING ACROSS THE MODEL SPECTRUM SUGGESTS FRIDAY WILL REMAIN CHARACTERED BY THE PRE-FRONTAL WARM SECTOR...WITH ANY POSSIBLE LATE DAY/EVENING CONVECTIVE CHANCES ARRIVING TOO LATE TO DISRUPT ANOTHER DAY WITH HIGHS IN THE 80S. POTENTIAL IS THERE FOR AN ACTIVE PERIOD HEADING INTO THE UPCOMING WEEKEND...FRONTAL BOUNDARY EVENTUALLY ALIGNING OVER OR NEAR THE REGION FOR AN EXTENDED TIME AS THE AXIS BECOMES PARALLEL TO THE MEAN FLOW. THIS PATTERN WOULD SHAVE A FEW DEGREE OFF PROSPECTIVE HIGHS THIS WEEKEND RELATIVE TO THE THU/FRI WARMTH...STILL NEAR TO ABOVE NORMAL THROUGH THIS TIME. MARINE... SHOWERY CONDITIONS WITH THE CHANCE OF THUNDERSTORMS WILL EXIST UNDER PERSIST EAST TO NORTHEAST FLOW OVER THE SOUTHERN LAKE HURON BASIN AND POINTS SOUTHWARD THROUGH TONIGHT. FAVORABLE MARINE CONDITIONS ACROSS NORTHERN LAKE HURON DURING THIS TIME AS HIGH PRESSURE BUILDS INTO THE REGION. MODEST WAVE AND WIND CONDITIONS THROUGH THE MIDWEEK PERIOD AS HIGH PRESSURE SUSTAINS A WEAK GRADIENT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....CB UPDATE.......CB SHORT TERM...BT LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
120 PM EDT TUE MAY 5 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 503 AM EDT TUE MAY 5 2015 WV IMAGERY AND RUC ANALYSIS INDICATED CONFLUENT WRLY MID/UPPER LEVEL FLOW INTO THE NRN GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE SE CONUS INTO THE CNTRL PLAINS. WITH A SFC RIDGE EXTENDING FROM NW ONTARIO THROUGH THE NRN LAKES...LIGHT WINDS AND CLEAR SKIES OVER UPPER MI HAS ALLOWED TEMPS TO DROP OFF INTO THE MID AND UPPER 30S WITH SEVERAL INLAND COLD SPOTS IN THE UPPER 20S TO AROUND 30. CLOUDS AND TODAY...EXPECT THAT HIGH PRES WILL CONTINUE TO DOMINATE AS THE CLOUDS AND PCPN ASSOCIATED WITH A FRONTAL BOUNDARY FROM SRN IA INTO NRN IL REMAIN WELL TO THE SOUTH. MIXING TO 5K FT WITH 850 MB TEMPS FCST IN THE 6C TO 8C RANGE WILL SUPPORT HIGHS IN THE UPPER 60S TO AROUND 70...EXCEPT ALONG THE GREAT LAKES WHERE READING WILL REMAIN IN THE UPPER 50S AND LOWER 60S. SIMILAR TO MONDAY...AFTERNOON DEWPOINTS WILL DROP INTO THE LOWER 20S WITH RH VALUES FROM 15 TO 20 PCT. HOWEVER...WINDS WILL REMAIN LIGHT...AOB 10 MPH. TONIGHT...AS THE HIGH SHIFTS OFF TO THE EAST AND AND 850 MB WARM FRONT APPROACHES FROM THE SOUTH...EXPECT INCREASING CLOUDS OVERNIGHT. THIS WILL KEEP TEMPS FROM FALLING OFF AS MUCH WITH MIN READINGS IN THE UPPER 30S TO AROUND 40. WITH THE VERY DRY AIRMASS IN PLACE...THE SLOWER END OF GUIDANCE WAS FAVORED WITH THE PCPN ADVANCING FROM THE SOUTH. SO...NO PCPN MENTION WAS INCLUDED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 1248 PM EDT TUE MAY 5 2015 THE APEX OF THE 500MB RIDGE WILL RESIDE FROM N MANITOBA THROUGH CENTRAL UPPER AND LOWER MI AT 00Z THURSDAY WITH RAIN APPROACHING FROM THE W-SW. THIS RAIN IS ASSOCIATED WITH A WAVE IN THE 500MB SW FLOW OVER THE N PLAINS. SE FLOW IN THE EVENING AT THE SFC WILL TURN MORE OUT OF THE S OVERNIGHT...USHERING IN WARMER/MORE MOIST AIR. THIS AND 850MB TEMPS OF 11-12C SHOULD KEEP DOWNSLOPE AREAS WEDNESDAY NIGHT/THURSDAY MORNING FROM FALLING BELOW THE MID 50S FAR W. HIGHS ON THURSDAY IN THE LOW 80S OVER THE INTERIOR AND FAR W DOWNSLOPE AREAS LOOKS REASONABLE. OTHER LOCATIONS OVER THE E AND ACROSS THE TIP OF THE KEWEENAW PENINSULA WILL BE MAINLY IN THE 60S AND 70S. THE CONTINUED DRY CONDITIONS AND WARMER AIR...ALONG WITH INCREASING WINDS. WILL CONTINUE TO HIGHLIGHT THE BREEZY CONDITIONS AND MODERATE RH VALUES IN THE FWF. AFTERNOON CONVECTION IS STILL IN QUESTION FOR THURSDAY...WITH FCST SOLUTIONS STILL GOING ON THE IDEA THAT PRECIP WILL EITHER END UP JUST FAR W OF MAINLY OVER LAKE SUPERIOR AND TO OUR S. MUCH OF THAT WILL DEPEND ON THE EVOLUTION OF CONVECTION TO OUR SW. THE BEST INSTABILITY REMAINS WELL TO OUR SW...CLOSER TO THE NEARING COLD FRONT STRETCHING FROM THE SFC LOW OVER NW ONTARIO AND THE NW HALF OF MN. THERE IS STILL SOME TEMPORAL DISCREPANCIES BETWEEN THE FCST SOLUTIONS AT THIS POINT. THE 05/00Z ECMWF IS APPROX 6HRS SLOWER NOW THAN THE GFS. THIS IS A CHANGE FROM 24HRS AGO...WHEN THE ECMWF WAS ON THE FAST SIDE. AT THIS POINT IT LOOKS LIKE A BLENDED SOLUTION IS MOST REASONABLE...AS THE ECMWF IS BACKED UP BY THE SLOWER 05/00Z CANADIAN AND WHILE THE OPERATIONAL GFS IS QUICKEST IT IS RUNNING IN LINE WITH THE 05/12Z NAM. LOOK FOR THE LOW OVER CENTRAL ONTARIO AROUND 06Z FRIDAY TO EJECT NE...DRAGGING THE COLD FRONT OVER E MN/FAR W LAKE SUPERIOR ACROSS UPPER MI DURING THE DAY FRIDAY. A SECONDARY LOW RIDING UP THE COLD FRONT FROM THE S PLAINS FRIDAY AFTERNOON WILL ACT TO STALL THE FRONT ACROSS LOWER MI /AND POSSIBLY EVEN FAR E UPPER MI/ FRIDAY NIGHT INTO SATURDAY MORNING. STILL EXPECTING ANOTHER BREEZY DAY FRIDAY WITH WINDS OUT OF A MORE SW DIRECTION. NAM SOUNDINGS INDICATE THE POTENTIAL FOR OVER 30KT GUSTS. WHILE THE GFS AGREES...IT DOES HAVE A STRONGER INVERSION SET UP E WITH LIMIT MIXING...AND OVERALL LIGHTER WINDS OVER THE W. OVER THE W TWO-THIRDS OF UPPER MI A RIDGE OF HIGH PRESSURE WILL BE OVERHEAD SATURDAY MORNING...BUILDING IN FROM W CENTRAL CANADA. THE RIDGE WILL CONTINUE TO STRENGTHEN OVER THE AREA THROUGH SATURDAY NIGHT AS THE HIGH SHIFTS ACROSS MANITOBA AND ONTARIO. THE NEXT SYSTEM OF INTEREST WILL BE IN THE FORM OF LOW PRESSURE ACROSS THE CENTRAL PLAINS AT 12Z SUNDAY. WILL AGAIN FOLLOW A BLENDED SOLUTION FOR THIS TIME PERIOD AS THERE COULD BE SIGNIFICANT DIFFERENCES COMPARING THE ECMWF PLACEMENT OF THE LOW OVER S MN/SW WI AT 12Z AND THE GFS WHICH HAS IT STILL OVER NE/KS. THE LOW WILL LIKELY DRIFT ACROSS S WI /CLOSER TO THE ECMWF SOLUTION/ ON MONDAY...AND ACROSS S LOWER MI MONDAY NIGHT BEFORE EXITING E. WITH EITHER SOLUTION KEEPING THE LOW TO OUR S...WILL CONTINUE THE BEST CHANCE OF ANY PRECIP OVER THE S HALF OF THE CWA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 120 PM EDT TUE MAY 5 2015 EXPECT VFR CONDITIONS AND LIGHT WINDS AT ALL 3 TAF SITES THIS FCST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 503 AM EDT TUE MAY 5 2015 AS A TROUGH MOVES FROM THE PLAINS TO THE UPPER MS VALLEY...SRLY WINDS WILL INCREASE TO AROUND 25 KNOTS OVER THE EAST BY LATE THU INTO THU NIGHT. OTHERWISE...WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1249 PM EDT TUE MAY 5 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 503 AM EDT TUE MAY 5 2015 WV IMAGERY AND RUC ANALYSIS INDICATED CONFLUENT WRLY MID/UPPER LEVEL FLOW INTO THE NRN GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE SE CONUS INTO THE CNTRL PLAINS. WITH A SFC RIDGE EXTENDING FROM NW ONTARIO THROUGH THE NRN LAKES...LIGHT WINDS AND CLEAR SKIES OVER UPPER MI HAS ALLOWED TEMPS TO DROP OFF INTO THE MID AND UPPER 30S WITH SEVERAL INLAND COLD SPOTS IN THE UPPER 20S TO AROUND 30. CLOUDS AND TODAY...EXPECT THAT HIGH PRES WILL CONTINUE TO DOMINATE AS THE CLOUDS AND PCPN ASSOCIATED WITH A FRONTAL BOUNDARY FROM SRN IA INTO NRN IL REMAIN WELL TO THE SOUTH. MIXING TO 5K FT WITH 850 MB TEMPS FCST IN THE 6C TO 8C RANGE WILL SUPPORT HIGHS IN THE UPPER 60S TO AROUND 70...EXCEPT ALONG THE GREAT LAKES WHERE READING WILL REMAIN IN THE UPPER 50S AND LOWER 60S. SIMILAR TO MONDAY...AFTERNOON DEWPOINTS WILL DROP INTO THE LOWER 20S WITH RH VALUES FROM 15 TO 20 PCT. HOWEVER...WINDS WILL REMAIN LIGHT...AOB 10 MPH. TONIGHT...AS THE HIGH SHIFTS OFF TO THE EAST AND AND 850 MB WARM FRONT APPROACHES FROM THE SOUTH...EXPECT INCREASING CLOUDS OVERNIGHT. THIS WILL KEEP TEMPS FROM FALLING OFF AS MUCH WITH MIN READINGS IN THE UPPER 30S TO AROUND 40. WITH THE VERY DRY AIRMASS IN PLACE...THE SLOWER END OF GUIDANCE WAS FAVORED WITH THE PCPN ADVANCING FROM THE SOUTH. SO...NO PCPN MENTION WAS INCLUDED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 1248 PM EDT TUE MAY 5 2015 THE APEX OF THE 500MB RIDGE WILL RESIDE FROM N MANITOBA THROUGH CENTRAL UPPER AND LOWER MI AT 00Z THURSDAY WITH RAIN APPROACHING FROM THE W-SW. THIS RAIN IS ASSOCIATED WITH A WAVE IN THE 500MB SW FLOW OVER THE N PLAINS. SE FLOW IN THE EVENING AT THE SFC WILL TURN MORE OUT OF THE S OVERNIGHT...USHERING IN WARMER/MORE MOIST AIR. THIS AND 850MB TEMPS OF 11-12C SHOULD KEEP DOWNSLOPE AREAS WEDNESDAY NIGHT/THURSDAY MORNING FROM FALLING BELOW THE MID 50S FAR W. HIGHS ON THURSDAY IN THE LOW 80S OVER THE INTERIOR AND FAR W DOWNSLOPE AREAS LOOKS REASONABLE. OTHER LOCATIONS OVER THE E AND ACROSS THE TIP OF THE KEWEENAW PENINSULA WILL BE MAINLY IN THE 60S AND 70S. THE CONTINUED DRY CONDITIONS AND WARMER AIR...ALONG WITH INCREASING WINDS. WILL CONTINUE TO HIGHLIGHT THE BREEZY CONDITIONS AND MODERATE RH VALUES IN THE FWF. AFTERNOON CONVECTION IS STILL IN QUESTION FOR THURSDAY...WITH FCST SOLUTIONS STILL GOING ON THE IDEA THAT PRECIP WILL EITHER END UP JUST FAR W OF MAINLY OVER LAKE SUPERIOR AND TO OUR S. MUCH OF THAT WILL DEPEND ON THE EVOLUTION OF CONVECTION TO OUR SW. THE BEST INSTABILITY REMAINS WELL TO OUR SW...CLOSER TO THE NEARING COLD FRONT STRETCHING FROM THE SFC LOW OVER NW ONTARIO AND THE NW HALF OF MN. THERE IS STILL SOME TEMPORAL DISCREPANCIES BETWEEN THE FCST SOLUTIONS AT THIS POINT. THE 05/00Z ECMWF IS APPROX 6HRS SLOWER NOW THAN THE GFS. THIS IS A CHANGE FROM 24HRS AGO...WHEN THE ECMWF WAS ON THE FAST SIDE. AT THIS POINT IT LOOKS LIKE A BLENDED SOLUTION IS MOST REASONABLE...AS THE ECMWF IS BACKED UP BY THE SLOWER 05/00Z CANADIAN AND WHILE THE OPERATIONAL GFS IS QUICKEST IT IS RUNNING IN LINE WITH THE 05/12Z NAM. LOOK FOR THE LOW OVER CENTRAL ONTARIO AROUND 06Z FRIDAY TO EJECT NE...DRAGGING THE COLD FRONT OVER E MN/FAR W LAKE SUPERIOR ACROSS UPPER MI DURING THE DAY FRIDAY. A SECONDARY LOW RIDING UP THE COLD FRONT FROM THE S PLAINS FRIDAY AFTERNOON WILL ACT TO STALL THE FRONT ACROSS LOWER MI /AND POSSIBLY EVEN FAR E UPPER MI/ FRIDAY NIGHT INTO SATURDAY MORNING. STILL EXPECTING ANOTHER BREEZY DAY FRIDAY WITH WINDS OUT OF A MORE SW DIRECTION. NAM SOUNDINGS INDICATE THE POTENTIAL FOR OVER 30KT GUSTS. WHILE THE GFS AGREES...IT DOES HAVE A STRONGER INVERSION SET UP E WITH LIMIT MIXING...AND OVERALL LIGHTER WINDS OVER THE W. OVER THE W TWO-THIRDS OF UPPER MI A RIDGE OF HIGH PRESSURE WILL BE OVERHEAD SATURDAY MORNING...BUILDING IN FROM W CENTRAL CANADA. THE RIDGE WILL CONTINUE TO STRENGTHEN OVER THE AREA THROUGH SATURDAY NIGHT AS THE HIGH SHIFTS ACROSS MANITOBA AND ONTARIO. THE NEXT SYSTEM OF INTEREST WILL BE IN THE FORM OF LOW PRESSURE ACROSS THE CENTRAL PLAINS AT 12Z SUNDAY. WILL AGAIN FOLLOW A BLENDED SOLUTION FOR THIS TIME PERIOD AS THERE COULD BE SIGNIFICANT DIFFERENCES COMPARING THE ECMWF PLACEMENT OF THE LOW OVER S MN/SW WI AT 12Z AND THE GFS WHICH HAS IT STILL OVER NE/KS. THE LOW WILL LIKELY DRIFT ACROSS S WI /CLOSER TO THE ECMWF SOLUTION/ ON MONDAY...AND ACROSS S LOWER MI MONDAY NIGHT BEFORE EXITING E. WITH EITHER SOLUTION KEEPING THE LOW TO OUR S...WILL CONTINUE THE BEST CHANCE OF ANY PRECIP OVER THE S HALF OF THE CWA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 732 AM EDT TUE MAY 5 2015 WITH DRY HIGH PRESSURE DOMINATING...EXPECT VFR CONDITIONS AND LIGHT WINDS AT ALL 3 TAF SITES THIS FCST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 503 AM EDT TUE MAY 5 2015 AS A TROUGH MOVES FROM THE PLAINS TO THE UPPER MS VALLEY...SRLY WINDS WILL INCREASE TO AROUND 25 KNOTS OVER THE EAST BY LATE THU INTO THU NIGHT. OTHERWISE...WINDS ARE EXPECTED TO REMAIN AT OR BELOW 20 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
411 PM CDT Tue May 5 2015 .DISCUSSION... Issued at 409 PM CDT TUE MAY 5 2015 Active pattern will continue through the rest of the week, and into the weekend. Perhaps the quietest of the next several days will be this afternoon. Warm and muggy conditions persist across the area today, with temperatures in the middle 70s to lower 80s, with dewpoints in the upper 50s to lower 60s. RAP soundings indicate that the atmosphere is uncapped, which has allowed for the CU field to form across the area. However the lack of any appreciable forcing has prevented much in the way of thunderstorm development. That being said, with the uncapped environment there is enough weak forcing to get a few storms to form across central Missouri. These storms will generally be pretty scattered in nature across the area, but coverage will not be very great. Any shower will likely be rather brief in nature. No strong or severe weather is anticipated with any of these storms outside of a wind gust or two near the storm. These diurnally driven showers will likely fall apart and diminish around sunset. Over the next several days several shortwave troughs will be rolling through the area, bringing several chances of rain. The first appreciable chance for rain will be during the morning to early afternoon hours on Wednesday as a vorticity lobe will swing through the area, bringing some scattered convection. While there will be some instability in the area, on the order of 500 to 1000 J/kg the amount of instability will be somewhat meager. Deep layer shear will also be on the low side, with 20 to 30 kts of 0-6 km shear. So given those particular CAPE/shear parameters it doesn`t look like severe weather will be the main story for Wednesday, but some of those morning and afternoon storms could be strong, to perhaps isolated severe. With the instability axis generally lined up to the west, the farther east any storms form will have a lessor chance to be severe. For Thursday another area of low pressure will eject through the area, and perhaps be accompanied by convection rolling eastward off the High Plains. This should kick off another round of convection across the area. Thursday will likely bring quite a bit more instability with ML CAPE values approaching 1000 to 2000 J/kg, but shear will still be on the low end, with 0-6 km layer shear in the 20 to 30 kt range. Even though the CAPE/shear values are not incredibly high they will be ample to possibly produced some organized rotating cells, and perhaps an isolated supercell or two across the area. Once again, the main threats will be hail and wind for Friday brings a slightly different story, as a surface boundary will sag southward, and basically bisect the forecast area E-W. Friday looks to be a little more capped than the previous couple of days, and that convective inhibition is a bit more influenced by some moderate height rises across the Plains for that time period. With good turning in the atmosphere, characterized by veering-with-height wind profile deep shear will be a bit higher, and instability will be in the 1000 to 2000 J/kg range any storm that is able to go up on Friday has a chance to be severe. If a storm does latch itself to the boundary, which will be somewhere near I-70 it could get a little extra low level turning, which would make any storm in that area even stronger. Synoptically speaking Friday doesn`t seem to bring much in the way of severe weather potential, but the mesoscale forecast closer to the event might reveal some potential for some isolated to scattered severe storms. By Saturday, the chances for severe weather start to synoptically increase. A very large trough, off to the west, will eventually take on a negative tilt and move through the Central Plains this weekend. Saturday still looks to be a little too far west to bring much in the way of widespread severe weather to the area. But during the overnight hours on Saturday night into Sunday morning the convection that occurs over the western and central plains will likely roll through the area. Convection during this overnight period would likely not be as organized, but it could roll through as an organized MCS, bringing a low end hail threat, but a larger wind threat Saturday night into Sunday morning. While this time period is still quite a way out, and much will depend on how things pan out closer to the event, Sunday is looking to be the day to watch as far as widespread severe weather across eastern Kansas and western Missouri is concerned. Recent runs of the GFS and ECMWF indicate a very potent mid level trough moving through the area Saturday night and Sunday. At the surface there will likely be a dry line somewhere between KDDC and KEMP. Where exactly the dry line sets up will dictate whether heightened concern for significant severe weather is warranted on Sunday. Should the dry line set up farther west, as is indicated by the GFS, then the area might be spared the brunt of the severe weather. But if it sets up near KEMP or even a little farther east, then this area could see a rather significant severe weather day on Sunday. But again, despite the synoptic signal, and with the timing so far out, and with mesoscale features playing a big roll in how convection plays out it`s much too early to get super concerned about severe weather this weekend. Also, despite the uncertainty regarding the timing, location, and severity of the thunderstorm activity through the rest of the week and into the weekend, there is also a very strong signal to support a prolonged period of multiple rounds of heavy rain. Some areas could see higher amounts, and some locations could see lower amounts, but generally speaking there appears to be a good signal for several inches of rain (perhaps up to 5 inches in some areas) through the next 5 to 7 days. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon) Issued at 1228 PM CDT TUE MAY 5 2015 Made some wholesale changes to this forecast. Most notably added a VCTS group for this afternoon. Cumulus field on satellite, as well as HRRR model guidance suggests a few scattered cells will be possible across the area this afternoon. Tough call whether or not the terminals will be directly affected, but there could be some vicinity issues. Also, overnight added some wind gusts, per model guidance. RAP sounding for the overnight period is a bit enigmatic with respect to gusts reaching to surface due to diurnal decoupling, but would suggest that if gusts don`t occur that a LLWS concern will develop overnight, with winds around 40 kts about 800 feet off the surface. Also added -SHRA group with VCTS for 15z Wed for rain showers encroaching from the west. J. Leighton && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ DISCUSSION...Leighton AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
346 PM EDT TUE MAY 5 2015 .SYNOPSIS... A FRONTAL ZONE WILL REMAIN NEARLY STATIONARY OVER THE MID-ATLANTIC STATES TONIGHT THROUGH WEDNESDAY. SOME SHOWERS WILL MOVE ALONG AND NORTH OF THE FRONT BRINGING A CHANCE FOR SOME RAIN TO SOUTHERN NEW YORK AND NORTHERN PENNSYLVANIA. THE BEST CHANCE FOR RAIN WILL BE TONIGHT AND EARLY WEDNESDAY. HIGH PRESSURE WILL RETURN ON THURSDAY BRINGING WARM DRY WEATHER. AN APPROACHING COLD FRONT MAY TRIGGER A FEW SCATTERED SHOWERS OR THUNDERSTORMS LATER FRIDAY AFTERNOON. && .NEAR TERM /UNTIL 6 AM WEDNESDAY/... MAIN FORECAST QUESTION FOR TONIGHT WILL BE THE IMPACT OF A SHORT WAVE AND ASSOCIATED AREA OF RAIN MOVING EAST FROM THE SOUTHERN GREAT LAKES TOWARD NORTHERN PENNSYLVANIA AND SOUTHERN NY. THE NAM/GFS/ECMWF AND SREF ARE ALL IN REASONABLY GOOD AGREEMENT THAT THE BEST CHANCE OF RAIN WILL BE ACROSS NORTHERN PA THIS EVENING WITH LOWER CHANCES FARTHER NORTH AND EAST OVERNIGHT. THE IDEA THAT RAIN MAY STRUGGLE TO REACH VERY FAR EAST OF I-81 IN NY STATE APPEARS REASONABLE GIVEN THAT SURFACE HIGH PRESSURE WILL BE BUILDING SOUTHEAST TOWARD THAT AREA OVERNIGHT. LATEST RADAR ANIMATIONS ARE ALREADY INDICATING A SLUG OF MODERATE TO HEAVY RAIN MOVING FROM SOUTHERN ONTARIO ACROSS SW NY AND NORTHWEST PA. THE LAST FEW RUNS OF THE HRRR INDICATE THAT SOME OF THIS RAIN WILL MOVE ACROSS SOUTHERN NY THROUGH MID- EVENING REACHING THE CATSKILLS BEFORE MIDNIGHT. THIS SCENARIO IS A BIT FARTHER NORTH AND EAST THAN SOME OF THE LOWER-RESOLUTION OPERATIONAL MODELS. BASED ON ALL OF THIS HAVE GONE WITH LIKELY POPS THIS EVENING INTO THE OVERNIGHT FOR NORTHERN PA AND THE SOUTHERN TIER OF NY WITH JUST CHC POPS FARTHER NORTH. THUNDER CHANCES LOOK LOW WITH NO INSTABILITY SHOWING UP ON ANY MODEL FORECAST SOUNDINGS. && .SHORT TERM /6 AM WEDNESDAY THROUGH FRIDAY/... SHOWERS WILL BE WEAKENING AND PUSHING SOUTH AND SOUTHEAST EARLY WEDNESDAY. CLOUDS WILL LINGER THROUGH MUCH OF THE DAY ACROSS NORTHERN PA AND SOUTHERN NEW YORK RESULTING IN A SLIGHTLY COOLER DAY ACROSS THOSE AREAS. HIGH PRESSURE WILL BUILD ACROSS THE AREA AT THE SURFACE AND ALOFT LATER WEDNESDAY THROUGH THURSDAY NIGHT BRINGING DRY WEATHER ALONG WITH A RETURN TO WELL ABOVE NORMAL TEMPERATURES BY THURSDAY AFTERNOON. WARM AND SLIGHTLY MORE HUMID WEATHER CAN BE EXPECTED FOR FRIDAY WITH JUST A SMALL CHANCE FOR AN AFTERNOON THUNDERSTORM. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... 2 PM UPDATE... FOLLOWED WPC GUIDANCE WHICH LOOKED GOOD. WARM AND DRY MUCH OF THE WEEKEND THEN BEST CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY. VERY WARM WITH HUMIDITY THIS WEEKEND UNDER A LARGE UPPER LEVEL RIDGE. A SURFACE BOUNDARY WILL BE JUST OF THE CWA IN SE CANADA WHICH STAYS THERE ALL OF THE LONG TERM. THE BIGGEST QUESTION IS WHERE THIS SETS UP AND STAYS. MODELS DIFFER ON THIS. WPC LEANS ON EURO WHICH KEEPS THE BOUNDARY IN CANADA WHILE THE GFS DROPS IT INTO PA SUN AND MON. HAVE FOLLOWED WPC AND HAVE CHC POPS FAR NORTH SAT NGT THEN EVERYONE SUNDAY. A COLD FRONT MOVES THROUGH TUESDAY WITH THE BEST CHANCE OF THE WEEK. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... 130 PM UPDATE... VFR NOW WITH HIGH CLOUDS. RAIN MOVING EAST FROM THE WRN SRN TIER WILL MAKE IT TO ELM BGM AND MAYBE ITH THIS EVE. VSBYS AND CIGS SHOULD DROP TO MVFR LATE TONIGHT BGM/ELM. SYR AND RME WILL STAY DRY AND VFR. AS THE LARGE WEST TO EAST AREA OF RAIN SINKS SOUTH AVP WILL HAVE RAIN SHORTLY AFTER MIDNIGHT WHICH WILL CONTINUE TO MIDDAY. AGAIN AVP SHOULD FALL TO MVFR AROUND 9Z. AS THE RAIN MOVES SOUTH OUT OF ELM BGM CONDITIONS WILL IMPROVE TO VFR AT ELM AROUND 14Z AND AT BGM AFTER 16Z. AVP SHOULD IMPROVE CLOSE TO 18Z AS RAIN ENDS. NW TO N WIND AT 5 KTS SHIFTING TO NE TONIGHT AND EAST WED. TONIGHT MANY LOCATIONS WILL BE LIGHT AND VARIABLE OR CALM. .OUTLOOK... WED AFTN-SAT...MAINLY VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MSE NEAR TERM...MSE SHORT TERM...MSE LONG TERM...TAC AVIATION...TAC
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
307 PM CDT TUE MAY 5 2015 .DISCUSSION... SCATTERED SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO DEVELOP ACROSS SE TX IN A NARROW CORRIDOR OF DEEPER MOISTURE. AIR MASS IS NOT QUITE AS WORKED OVER THE W-SW ZONES AND FEEL ACTIVITY WILL DRIFT TOWARD THE UNMODIFIED AIR FOR THE REST OF THE AFTN AND EVENING. PRECIP SHOULD END EARLY THIS EVENING AS THE DISTURBANCE THAT MOVED INTO THE AREA FROM THE EAST MERGES WITH THE UPPER TROUGH. A RIBBON OF DEEPER MOISTURE WILL PERSIST OVER THE W-SW ZONES THROUGH WEDNESDAY. CAN`T REALLY FIND A SFC TRIGGER AND UPPER LEVEL WINDS ARE LESS DIVERGENT TOMORROW BUT WILL MAINTAIN CHANCE POPS OUT WEST DUE TO THE HIGHER MOISTURE CONTENT. THE HRRR AND THE RAP ARE AGGRESSIVE IN DEVELOPING A BAND OF SHOWERS OVER THE SW ZONES LATE TONIGHT IN THE AXIS OF DEEPER MSTR. THE NAM SOUNDINGS ON WEDNESDAY LOOK FAIRLY POTENT OVER THE WESTERN HALF OF THE CWA WITH CAPE VALUES ABOVE 3000...LI VALUES ARE -8 AND A WEAK INVERTED V SIGNATURE. UPPER LEVEL RIDGING OVER THE GULF AMPLIFIES INTO SE TX THU-SAT WITH A SERIES OF UPPER LEVEL DISTURBANCES PASSING WELL TO THE WEST OF THE CWA. WESTERN AREAS COULD GET CLIPPED BY A DISTURBANCE OR TWO BUT FOR THE MOST PART...FEEL SE TX WILL REMAIN WARM AND HUMID BUT GENERALLY RAIN FREE. A STRONGER UPPER LEVEL TROUGH WILL PIVOT ACROSS THE SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS ON MONDAY. THE UPPER RIDGE OVER THE GULF IS FLATTENED A BIT AND NUDGED TO THE EAST. THIS SHOULD BRING SOME OF THE ACTIVE WEATHER A BIT FURTHER EAST SUN-TUE. A WEAK COLD FRONT WILL ALSO APPROACH SE TX ON TUESDAY AND PROBABLY STALL SOMEWHERE OVER THE AREA BEFORE RETREATING NORTH. LOOKS LIKE MON/TUE COULD BECOME ACTIVE WITH PERIODS OF SHRA/TSRA. 43 && .MARINE... PRESSURE GRADIENT REMAINS FAIRLY TIGHT WITH SMALL CRAFT ADVISORY CONDITIONS BEING OBSERVED IN THE BAYS AND SLIGHTLY UNDER CRITERIA OFFSHORE. HOWEVER...GUIDANCE SUGGESTS SPEEDS WILL EVENTUALLY BUMP UP TO 20KTS OFFSHORE LATER THIS EVENING SO AM GOING TO HOIST THE SCA FLAGS FOR ALL COASTAL WATERS OVERNIGHT. MODERATE ONSHORE FLOW SHOULD PREVAIL THRU THE WEEKEND WITH INTERMITTENT PERIODS WHEREAS CAUTION FLAGS MIGHT BE REQUIRED. TIDES ARE CURRENTLY RUNNING 1-1.5 FEET ABOVE NORMAL. THIS ALONG WITH ELEVATED SEAS AND SURF WILL PRODUCE STRONGER THAN NORMAL RIP CURRENTS (AS WAS OBSERVED BY GALVESTON BEACH PATROL TODAY) THRU MIDWEEK. 47 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 69 84 71 84 71 / 30 30 20 30 20 HOUSTON (IAH) 71 84 72 86 72 / 20 20 10 20 10 GALVESTON (GLS) 73 81 74 81 75 / 20 20 10 20 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 3 AM CDT WEDNESDAY FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 4 PM CDT THIS AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
106 PM CDT TUE MAY 5 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE MOSTLY MID LEVEL CLOUDS WITH A FEW LOW AND HIGH CLOUDS ACROSS THE CWA EARLY THIS AFTERNOON. CEILINGS WERE NEAR 2200FT AT KAPY AND KPIL TO NEAR 6000FT AT KEBG. EXPECT VFR CONDITIONS TO PREVAIL THE REST OF THE AFTERNOON INTO THE EVENING BEFORE MVFR CEILINGS DEVELOP TONIGHT AS LOW TO MID LEVEL MOISTURE INCREASES ACROSS THE RIO GRANDE VALLEY TONIGHT INTO WED MORNING. && .PREV DISCUSSION... /ISSUED 629 AM CDT TUE MAY 5 2015/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...MVFR CIGS DID NOT MATERIALIZE AT BRO AND HRL WITH THOSE CIGS AFFECTING MFE ATTM. GUSTY WINDS TO BEGIN AROUND 14Z AT WHICH TIME THOSE CIGS SHOULD BEGIN TO SCATTER TO VFR BY LATE MORNING. GUSTS TO 30 KNOTS APPEAR POSSIBLE ESPECIALLY AT MFE WHERE STRONGER LOW LEVEL WINDS RESIDE. WINDS WILL DECREASE AFTER SUNSET BUT GUSTS WILL CONTINUE TILL AROUND MIDNIGHT. MVFR CIGS WILL BUILD BACK IN AFTER SUNSET WHICH WILL CONTINUE THROUGH THE REST OF THE TAF PERIOD. PREV DISCUSSION... /ISSUED 416 AM CDT TUE MAY 5 2015/ SHORT TERM /NOW THROUGH WEDNESDAY/...UPPER TROF ACROSS THE FOUR CORNERS REGION WILL OPEN UP AND WEAKEN AS IT HEADS NORTHEASTWARD INTO COLORADO THEN BECOME ABSORBED IN THE DEEPENING LARGER SCALE TROUGH ACROSS THE WESTERN CONUS. DIFFLUENCE REMAINS ACROSS THE AREA BUT BETTER DYNAMICS ASSOCIATED WITH THE UPPER TROF WILL REMAIN WELL REMOVED FROM THE AREA. 700MB FLOW STRENGTHENS AND REINFORCES MID LEVEL CAPPING WITH DRY AIR ADVECTING FROM THE MEXICAN PLATEAU AND OVER SPREADING THE AREA. LEFT SLIGHT CHANCE POPS THIS MORNING FOR FAR WESTERN SECTIONS BUT BELIEVE CAP WILL KEEP THE LID ON MOST IF NOT ALL PRECIPITATION TODAY. HRRR AND NAM12 SUPPORT THIS IDEA. BREEZY CONDITIONS CONTINUE TODAY WITH DEEPENING LOW PRESSURE ACROSS WEST TEXAS WITH GUSTS APPROACHING 30 MPH. THERE ARE INDICATIONS IN THE MODELS OF THUNDERSTORMS DEVELOPING ON THE HIGHER TERRAIN THIS EVENING AND MOVE EASTWARD TOWARDS OUR AREA BUT DRY AIR SHOULD WEAKEN THEM BEFORE MAKING ACROSS THE RIVER. THEREFORE WILL KEEP FORECAST DRY TONIGHT. BREEZY CONDITIONS CONTINUE WEDNESDAY WITH ANOTHER ROUND OF 700MB DRY AIR ADVECTING FROM THE WEST. CONDITIONS WILL BE FAIRLY SIMILAR TO THE PAST SEVERAL DAYS. HIGHS IN THE 80S THE NEXT SEVERAL DAYS AND PERHAPS REACHING 90 DEGREES IN THE FAR NORTHWESTERN SECTIONS OF ZAPATA COUNTY. LOWS WILL BE IN THE 70S. LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...AS LOW PRESSURE TROUGHS DEEPEN ACROSS SW U.S. AND JUST OFF THE SE U.S. COAST MID TO UPPER LEVEL RIDGE BUILDS OVER SOUTH TEXAS AND THE WESTERN GULF. THIS SHOULD IN A MOSTLY DRY RAINFREE WED NIGHT THROUGH SUNDAY PERIOD. NOT UNTIL THE WESTERN TROUGH BEGINS TO MOVE NORTHEAST LATE NEXT WEEKEND INTO EARLY NEXT WEEK WILL THERE BE SOME INCREASE IN THE CHANCE OF RAIN. MODELS REMAIN RATHER PERSISTENT IN THIS PATTERN AND HAVE BEEN IN GOOD CONSISTENCY MAKING FOR A BETTER THAN AVERAGE CONFIDENCE IN THE OUTGOING FORECAST. OVERALL, THE EARLY DOG DAYS OF SUMMER WILL BE SETTING UP AS THE BUILDING UPPER RIDGE AND STRONG CAPPING INVERSION BETWEEN 850-700MB TO DOMINATE. THE BUILDING RIDGE PROMOTES A DIVERGENT Q VECTOR FIELD OR A CONFLUENT FLOW ALOFT AND THE 850-700MB CAPPING INVERSION STRENGTHENS WITH A THE PERSISTENT SOUTHWEST FLOW. WITHOUT ANY LIFTING MECHANISM AND DISTURBANCES/VORT MAXES LIKELY TO BE DIVERTED NORTHEAST OF THE AREA DO NOT SEE ANY SIGNIFICANT CHANCE OF RAIN. WITH THAT SAID HAVE KEPT THE LOW CHANCE POPS ACROSS THE NW ZONES JUST IN CASE A ROUGE THUNDERSTORM MOVES IN FROM THE SIERRA MADRE. WARM/HOT, HUMID AND BREEZY WILL BE THE WORD THROUGH AT LEAST SUNDAY WITH WINDIEST DAYS NEXT WEEKEND AS THE UPPER TROUGH OVER THE DESERT SW LIFTS INTO THE CENTRAL PLAINS STRENGTHENING THE PRESSURE GRADIENT. AS WE MOVE INTO NEXT WEEK MODELS SUGGEST AN INCREASE IN RAIN CHANCES. THE WEAKENING OF THE RIDGE AND A TRAILING COLD FRONT MOVING INTO CENTRAL TEXAS ALONG WITH POOLING MOISTURE SOUTH OF THE BOUNDARY LOOKS TO THE INGREDIENTS NEEDED TO GET A FEW STORMS IN OUR REGION. HAVE BROAD BRUSHED THE CWA WITH LOW GRADE POPS NEXT MONDAY AND TUESDAY TO ACCOMMODATE THE MODEL CONSENSUS. MARINE...NOW THROUGH WEDNESDAY...MODERATE SOUTHEAST WINDS AND MODERATE SEAS WILL CONTINUE AS HIGH PRES REMAINS DOMINANT OVER THE SOUTHEAST U.S. AND THE NORTH GULF...COUNTERBALANCED BY SOMEWHAT LOWER PRESSURE OVER THE SOUTHERN HIGH PLAINS. WINDS AND SEAS MAY INCREASE SLIGHTLY AT TIMES...WITH SMALL CRAFT EXERCISE CAUTION TO LOW END SMALL CRAFT ADVISORY CONDITIONS POSSIBLE. WEDNESDAY NIGHT THROUGH SUNDAY...A MODERATE TO STRONG PRESSURE GRADIENT TO PERSIST THIS PERIOD. BROAD HIGH PRESSURE OVER THE GULF TO INTERACT WITH LOWER PRESSURE OVER NW TEXAS TO PRODUCE MARGINAL SMALL CRAFT ADVISORY CONDITIONS WEDNESDAY NIGHT THROUGH FRIDAY. LOW PRESSURE STRENGTHEN OVER THE WEEKEND WITH A POSSIBLE UPTICK IN WINDS AND SEAS. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 61/67/BIRCHFIELD
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1126 AM MDT TUE MAY 5 2015 .UPDATE...VISIBLE SATELLITE IMAGERY AND WYDOT WEBCAMS CONTINUE TO SHOW AREAS OF DENSE FOG AROUND CHEYENNE TO THE SUMMIT EAST OF LARAMIE...AND BETWEEN SINCLAIR AND RAWLINS WY. WE UPDATED TO INCLUDE THE RAWLINS AREA ALONG I-80 IN THE DENSE FOG ADVISORY AND TO EXTEND THE ADVISORY UNTIL NOON MDT. EXPECT THE FOG WILL START TO LIFT BY EARLY AFTERNOON. OTHERWISE...NO FURTHER CHANGES NEEDED IN THE NEAR TERM FORECAST. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 WEBCAMS ALONG INTERSTATE 80 HAVE CONSISTENTLY SHOWN DENSE FOG FROM THE SUMMIT TO CHEYENNE OVER THE PAST FEW HOURS. DECIDED TO ADD CENTRAL LARAMIE COUNTY (CHEYENNE) TO THE DENSE FOG ADVISORY THRU 16Z WITH THE CYS OBS DROPPING TO ONE QUARTER MILE. THE LOW CLOUDS AND FOG WILL REMAIN QUITE PERSISTENT THROUGH THE MORNING WITH THE HRRR MODEL INDICATING LIFR/IFR CONDITIONS THROUGH 18Z FROM THE INTERSTATE 80 SUMMIT EASTWARD TO CHEYENNE COUNTY. THIS MAKES SENSE AS THE OVERALL SFC PATTERN OF VERY MOIST SOUTH TO SOUTHEAST WINDS WILL CONTINUE THROUGH THE MORNING. WATER VAPOR IMAGERY SHOWS THE SUBTROPICAL UPPER LOW SPINNING OVER NORTHEAST ARIZONA. THE MODELS MOVE THIS FEATURE TO THE NORTHEAST OVER THE COURSE OF THE DAY TO NEAR NORTHERN COLORADO BY THIS EVENING. ONLY AN ISOLATED TO SCATTERED COVERAGE OF SHOWERS IS EXPECTED THROUGH THE EARLY AFTN ALONG THE COLORADO BORDER. HOWEVER...MIDLVL HEIGHT FALLS WILL COMBINE WITH INCREASING DEEP LAYER MOISTURE TO PROMOTE A MORE WIDESPREAD COVERAGE BY THE LATE AFTN AND EARLY EVENING. MOISTURE IS PLENTIFUL WITH THIS SYSTEM...IN FACT PW VALUES OF 0.75-1.0 INCHES OVER THE PLAINS ARE 2 STANDARD DEVIATIONS ABOVE NORMAL FOR EARLY MAY. THUS...WITH RELATIVELY SLOW STORM MOTIONS...LOCALLY HEAVY RAIN WILL BE A CONCERN ESPECIALLY OVER THE NEBRASKA PANHANDLE. WHILE ISOLATED TSTMS WILL BE POSSIBLE THIS AFTN...THE VERY WEAK INSTABILITY AND SHEAR WILL MAKE STRONG STORMS UNLIKELY. SPC HAS DROPPED THE MARGINAL THREAT OVER THE SOUTHERN PANHANDLE. WITH THE MIDLVL DISTURBANCE OVERHEAD TONIGHT...WILL KEEP A CHANCE OF SHOWERS GOING. SOUTHEAST SFC WINDS ARE IN PLACE THRU 12Z WED...SO FOG WILL AGAIN BE A THREAT OVER PORTIONS OF THE AREA. THE SHORTWAVE WILL PUSH INTO WESTERN SOUTH DAKOTA/NEBRASKA BY WED AFTN. THE MODELS SHOW THE HIGHEST QPF OVER THE PLAINS OF SOUTHEAST WY AS A SFC COLD FRONT INTERACTS WITH GOOD MOISTURE. WILL HAVE ISOLATED TSTMS DURING THE AFTN WITH SOME LIMITED CAPE. PRECIP CHANCES DROP OFF WED EVENING BEHIND THE FRONT AS A DRIER AIRMASS MOVES IN. THERE COULD ACTUALLY BE A 18-24 HR PERIOD FROM WED EVENING THRU THURS AFTN WHEN MUCH OF THE CWA WILL BE PRECIP FREE. SCATTERED STORMS WILL ONCE AGAIN DEVELOP ALONG AND WEST OF THE LARAMIE RANGE BY THURS AFTN...WITH LIMITED COVERAGE OVER THE PLAINS IN A MORE STABLE AIRMASS. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 345 AM MDT TUE MAY 5 2015 UNSETTLED WEATHER CONTINUES IN THE LONG TERM. MEDIUM RANGE GUIDANCE CONTINUES TO ADVERTISE THE POSSIBILITY OF WINTER WEATHER RETURNING TO THE AREA LATE IN THE WEEKEND. STARTING OFF THURSDAY NIGHT...WE STILL HAVE THE STALLED SURFACE BOUNDARY LAYING ALONG THE LARAMIE RANGE...OR SLIGHTLY WEST. BOTH THE GFS AND ECMWF VERY SIMILAR BRINGING ANOTHER PIECE OF ENERGY NORTHEAST FROM THE DESERT SOUTHWEST TO INTERACT WITH THIS BOUNDARY...SO WILL KEEP CHANCE POPS GOING FOR THE THURSDAY NIGHT TIME FRAME. PROBABLY PRETTY LIGHT SHOWERS THOUGH AS HAS BEEN THE CASE THE PAST FEW NIGHTS. CONVECTION PICKS UP THROUGH FRIDAY AFTERNOON WITH BOTH MODELS CONCENTRATING ON THE SOUTHERN PANHANDLE AND NORTHEASTERN COLORADO. SOUTHEAST UPSLOPING WINDS TO CONTINUE. GFS AND ECMWF CONTINUE TO AGREE ON A CLOSED LOW ROUNDING THE BASE OF THE LONGWAVE TROUGH SATURDAY MORNING AND BEGINNING TO LIFT NORTHEAST INTO SOUTHWESTERN COLORADO SATURDAY AFTERNOON. OUR FORECAST AREA IS SQUARE IN THE WRAP AROUND MOISTURE TO THE NORTH OF THIS LOW. ECMWF A LITTLE FASTER ON MOVEMENT OVER THE GFS...MOVING THE LOW INTO CENTRAL NEBRASKA ROUGHLY 12 HOURS FASTER THAN THE GFS. BOTH ARE COLD THOUGH ON 700MB TEMPERATURES AND COLD ENOUGH FOR WIDESPREAD SNOW. BOTH ARE SHOWING 850MB WINDS OF 40 TO 45KTS ACROSS THE PANHANDLE AND EASTERN WYOMING. WINTER IS NOT DONE WITH SOUTHEAST WYOMING AND WE NEED TO BE WATCHING THE EVOLUTION OF THIS EVENT AS HEAVY SNOW AND WINTER HEADLINES ARE DEFINITELY A POSSIBILITY FOR PORTIONS OF THE FORECAST AREA...POSSIBLY EVEN THE PANHANDLE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING) ISSUED AT 1126 AM MDT TUE MAY 5 2015 WIDESPREAD IFR/LIFR CEILINGS AND VISIBILITIES TO PERSIST ALONG A KCYS TO KSNY LINE THROUGH TONIGHT WITH VFR AND SCTD MVFR CIGS ELSEWHERE TODAY...BECOMING MORE WIDESPREAD MVFR/IFR THIS EVENING. SCTD SHOWERS SHOULD SPREAD NORTH ACROSS THE AREA TONIGHT. && .FIRE WEATHER... ISSUED AT 345 AM MDT TUE MAY 5 2015 A COOL AND WET WEATHER PATTERN WILL KEEP FIRE WEATHER CONCERNS VERY LOW THROUGH THE WEEKEND. AFTERNOON AND EVENING SHOWERS WILL BE POSSIBLE TODAY THROUGH THURSDAY...WITH GOOD CHANCES FOR MEASURABLE RAIN. MORE SUBSTANTIAL PRECIPITATION AMOUNTS ARE LOOKING POSSIBLE BY LATE FRIDAY INTO SUNDAY ASSOCIATED WITH A STRONG STORM SYSTEM. MINIMUM RELATIVE HUMIDITY VALUES SHOULD BE WELL ABOVE CRITICAL THRESHOLDS THROUGH THE PERIOD. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...DENSE FOG ADVISORY UNTIL NOON MDT TODAY FOR WYZ116>118. NE...NONE. && $$ SHORT TERM...ZF LONG TERM...GCC AVIATION...RE FIRE WEATHER...ZF