Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/15/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1115 AM MDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 841 AM MDT TUE AUG 13 2013
HAVE CUT BACK POPS TO ZEROS...BASED ON NEAR ZERO CLOUDS ACROSS
THE CWA. WILL SEE A SLOW BUT STEADY INCREASE IN CONVECTION BY
THIS AFTERNOON...FIRST ACROSS THE MTS AND THEN SPREADING EWD TO
THE PLAINS. LOOKS LIKE A PRETTY TYPICAL AUG DAY. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM MDT TUE AUG 13 2013
...FLASH FLOOD THREAT FOR BURN SCARS IN EL PASO/TELLER COUNTIES TODAY...
MOST OF SHOWER/TSTORM ACTIVITY HAS DIMINISHED ACROSS THE AREA THIS
MORNING AND MODELS ARE HAVING A DIFFICULT TIME WITH THIS AS BOTH
NAM12 AND GFS MAINTAIN PRECIPITATION ACROSS THE SOUTHEAST PLAINS
THROUGH THE MORNING HOURS. THIS LEADS TO LOWER CONFIDENCE IN QPF
FORECAST TODAY AS MODELS PLAY CATCH UP WITH WHAT IS CURRENTLY GOING
ON.
IN WV PICS...APPEARS MAIN SHORTWAVE WHICH HELPED FIRE OFF
YESTERDAY`S CONVECTION HAS ALREADY PUSHED EAST OF THE AREA INTO
CENTRAL KS. HOWEVER...ANOTHER SHORTWAVE IS EVIDENT IN THE MOISTURE
PLUME ACROSS NW CO/SRN WY...WHICH WILL BE TRANSLATING SLOWLY
EASTWARD THROUGH THE UPPER RIDGE ACROSS THE AREA TODAY. AT THE
SFC...DEW POINTS HAVE INCREASED ACROSS THE PLAINS WITH READINGS
MAINLY IN THE 50S. STRATUS IS NOT AS WIDESPREAD AS MODELS
PORTRAYED...PROBABLY A RESULT OF THEIR OVERZEALOUS QPF FORECAST THIS
MORNING. SUSPECT WE WILL SEE SOME STRATUS DEVELOP AND SPREAD
WESTWARD INTO SOUTHEAST PLAINS TOWARDS DAWN BUT IT WILL PROBABLY BE
FAIRLY SHALLOW AND MORE PATCHY IN NATURE EXCEPT ACROSS THE SE CORNER
WHERE IT MAY BE MORE WIDESPREAD. THUS ANY STRATUS WILL LIKELY BURN
OFF FAIRLY QUICKLY THIS MORNING. WITH MORE CLEARING THIS
AFTERNOON...WE WILL BE MORE LIKELY TO SEE SUFFICIENT HEATING TO
TRIGGER ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE SOUTHEAST MOUNTAINS AND ADJACENT PLAINS. WITH LOW LEVEL FLOW
REMAINING EASTERLY...DEW POINTS SHOULD REMAIN IN THE 50S ACROSS THE
PLAINS/I-25 CORRIDOR. THIS WILL LEAD TO CAPE VALUES GENERALLY
BETWEEN 500-1000 J/KG...NOT TERRIBLY HIGH...BUT SUFFICIENT TO
PRODUCE A FEW STRONG STORMS. THUS GREATEST CONCERN WILL BE THE EL
PASO/TELLER COUNTY AREAS WHERE THE SUSCEPTIBLE BURN SCARS WILL BE
UNDER THE GUN FOR MORE HEAVY RAINFALL TODAY. ALTHOUGH NAM12 HAS
TAMED DOWN ITS QPF FCST FOR TODAY VS YESTERDAY`S RUNS...OTHER MODELS
SUCH AS GFS...HIGH RES WRF (LOCAL AND NSSL)AND HRRR BOTH HIT
PORTIONS OF THE SE MTS/ADJACENT PLAINS WITH POCKETS OF HEAVY
RAINFALL. WITH THE SATURATED GROUND FROM RECENT RAINS ACROSS TELLER
AND EL PASO COUNTY...WILL BE PUTTING OUT ANOTHER FLASH FLOOD WATCH
FOR TODAY. GREATEST THREAT WINDOW APPEARS TO BE FROM 2 PM TO 6 PM
FOR THE BURN SCARS THOUGH HRRR SEEMS TO BE TRENDING IT TOWARDS 1 PM
IN SOME OF ITS LATER RUNS. OF COURSE IF THE STRONGER STORMS PASS
AROUND THE BURN SCARS...THEN IT IS POSSIBLE THAT FLASH FLOODING WILL
NOT OCCUR...BUT WILL ERR ON THE SIDE OF CAUTION AS THE PROBABILITY
WILL BE THERE FOR A HIGH IMPACT EVENT SHOULD THE BURN SCARS BE
IMPACTED. THE CITY OF COLORADO SPRINGS COULD ALSO BE UNDER THE GUN
TODAY FOR FLASH FLOODING DUE TO THE SATURATED GROUND FROM
YESTERDAY`S HEAVY RAIN WHICH WILL EXACERBATE ANY RUNOFF TODAY SHOULD
STORMS HIT THAT REGION.
THUNDERSTORMS SHOULD SPREAD EASTWARD ACROSS THE PLAINS DURING THE
LATE AFTERNOON AND EVENING HOURS AS THE SHORTWAVE SLOWLY KICKS
THROUGH THE REGION. WILL DECREASE POPS QUICKLY AFTER 06Z AS
CONSENSUS OF THE MODELS IS TO KEEP CONVECTION GOING WELL TO THE
SOUTH ALONG FRONTAL BOUNDARY ACROSS EASTERN NM/SRN TX PANHANDLE.
GFS SEEMS TO BE THE OUTLIER IN KEEPING WIDESPREAD QPF ACROSS THE
PLAINS THROUGH 12Z...SO WILL DISCOUNT IT FOR NOW. STRATUS SHOULD BE
MORE WIDESPREAD ACROSS THE SE PLAINS TONIGHT.
NOT TO NEGLECT WESTERN AREAS...DRIER AIR OUT THAT WAY SHOULD KEEP
PCPN EFFICIENCIES WITH THUNDERSTORMS LOWER. PRECIP WATERS WILL BE
RUNNING AROUND .50 WHICH PUTS THEM BELOW 100% OF NORMAL. WITH
FORCING FROM THE SHORTWAVE EXPECTED TO IMPACT NORTHERN AREAS MORE SO
THAN THE SOUTHWEST...EXPECT THUNDERSTORMS TO BE MORE ISOLATED TO
SCATTERED IN COVERAGE ACROSS THE EASTERN SAN JUANS AND LA
GARITAS...AND WILL DIMINISH QUICKLY DURING THE EVENING HOURS. THE
WEST FORK BURN SCAR WILL NEED TO BE MONITORED FROM NOON TO 6 PM FOR
POCKETS OF HEAVIER RAIN SUFFICIENT TO CAUSE LOCALIZED
RUNOFF/POTENTIAL FLASH FLOOD PROBLEMS. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 528 AM MDT TUE AUG 13 2013
LONGER TERM METEOROLOGICAL CONCERNS INCLUDE POPS AND TEMPERATURES.
ABOVE SEASONAL POPS IN COMBINATION WITH BELOW SEASONAL TEMPERATURES
ARE EXPECTED FROM WEDNESDAY INTO WEDNESDAY NIGHT AS AVAILABLE
ATMOSPHERIC MOISTURE INTERACTS WITH THE DAILY OROGRAPHIC HEATING
CYCLE AS WELL AS SOME UPPER LIFT.
RECENT LONGER TERM FORECAST MODEL SOUNDINGS INDICATE THAT
LOCATIONS SUCH AS THE I-25 CORRIDOR SHOULD EXPERIENCE PRECIPITABLE
WATER VALUES NEARING ONE INCH AT TIMES WEDNESDAY AFTERNOON.
THE COMBINATION OF AVAILABLE ATMOSPHERIC MOISTURE AND AN
APPROACHING UPPER SHORT-WAVE(PER LATEST GFS40 PV15 FORECAST)
...ESPECIALLY OVER NORTHERN SECTIONS OF THE FORECAST DISTRICT
SHOULD ALLOW FOR ANOTHER ROUND OF ISOLATED TO SCATTERED WEDNESDAY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS OVER THE FORECAST
DISTRICT...ESPECIALLY EASTERN SECTIONS.
ONCE AGAIN...SOME OF THESE STORMS ON WEDNESDAY AFTERNOON AND
EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL AS
WELL AS POTENTIAL BURN SCAR FLOODING ISSUES...ESPECIALLY IF A
STRONGER STORM DEVELOPS OVER A BURN SCAR...SUCH AS THE WALDO
CANYON BURN SCAR...ETC. WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY AND ISSUE HYDRO/FLASH FLOOD HIGHLIGHTS/ADVISORIES/WARNINGS
AS NEEDED.
THEN...WARMER AND DRIER CONDITIONS SHOULD RETURN TO THE FORECAST
DISTRICT FROM LATER THURSDAY INTO AT LEAST EARLY SUNDAY AS AN
UPPER RIDGE BUILDS OVER ARIZONA AND NEW MEXICO. IN ADDITION...
FORECAST PRECIPITABLE WATER VALUES DROP TO BETWEEN 0.50 AND 0.70
INCHES OVER THE INTERSTATE 25 CORRIDOR DURING THIS TIME-FRAME.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
SHOULD BE NOTED OVER THE CWFA FROM LATER THURSDAY INTO EARLY
SUNDAY. EVEN THOUGH RELATIVELY UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM IMPACTS A
BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
IN ADDITION...STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO
DEVELOP OVER PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS FROM
THURSDAY INTO THURSDAY EVENING AS PROJECTED LOCALIZED CAPES/LIS IN
EXCESS OF 2000 J/KG AND -7C RESPECTIVELY INTERACT WITH PROJECTED
0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY IS THEN ANTICIPATED
FROM LATER SUNDAY INTO NEXT TUESDAY AS A NORTHERLY SURFACE SURGE
MOVING ACROSS EASTERN SECTIONS MONDAY INCREASES ATMOSPHERIC
MOISTURE AND INTERACTS WITH UPPER SHORTWAVES. FORECAST MODEL
SOUNDINGS PROJECT THAT PRECIPITABLE WATER VALUES OVER THE
INTERSTATE 25 CORRIDOR INCREASE TO OVER ONE INCH BY MONDAY
AFTERNOON.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR LOCALIZED
HEAVY RAIN AND ASSOCIATED FLASH FLOODING CONCERNS(ESPECIALLY OVER
THE AREA BURN SCARS) WILL BE POSSIBLE FROM LATER SUNDAY INTO NEXT
TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY.
FINALLY...LOW-GRADE GRADIENT WINDS AS WELL AS ABOVE AVERAGE
MID-AUGUST SEASONAL TEMPERATURES ARE ANTICIPATED OVER THE
MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO NEXT MONDAY
WITH THE WARMEST CONDITIONS EXPECTED THIS WEEKEND AS 700 MB
TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB TO AROUND 18C FROM THE
12C READINGS PROJECTED TODAY. MAXIMUM TEMPERATURES THIS WEEKEND
OVER MANY SECTIONS OF THE SOUTHEASTERN COLORADO PLAINS SHOULD
REACH WELL INTO THE 90S BOTH SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 11:15 MDT TUE AUG 13 2013
MAIN AVN CONCERN CONTINUES TO BE POTENTIAL FOR TS AT THE TAF SITES
THIS AFTERNOON AND EVE...FROM 20-21Z AT KALS AND KCOS...AND 22-24Z
FOR KPUB. COULD SEE SOME BRIEF HEAVY RAINFALL AND MVFR TO BRIEFLY
IFR CONDITIONS IN THE HEAVIEST STORMS. ALSO SOME SMALL HAIL POSSIBLE.
STORMS WILL MOVE TOT HE EAST AND SHOULD CLEAR THE TERMINALS BY
SUNSET OR SHORTLY AFTER...WITH JUST SOME LINGERING SHOWERS THIS
EVE. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ081-084-085.
&&
$$
UPDATE...ROSE
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
845 AM MDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 841 AM MDT TUE AUG 13 2013
HAVE CUT BACK POPS TO ZEROS...BASED ON NEAR ZERO CLOUDS ACROSS
THE CWA. WILL SEE A SLOW BUT STEADY INCREASE IN CONVECTION BY
THIS AFTERNOON...FIRST ACROSS THE MTS AND THEN SPREADING EWD TO
THE PLAINS. LOOKS LIKE A PRETTY TYPICAL AUG DAY. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM MDT TUE AUG 13 2013
...FLASH FLOOD THREAT FOR BURN SCARS IN EL PASO/TELLER COUNTIES TODAY...
MOST OF SHOWER/TSTORM ACTIVITY HAS DIMINISHED ACROSS THE AREA THIS
MORNING AND MODELS ARE HAVING A DIFFICULT TIME WITH THIS AS BOTH
NAM12 AND GFS MAINTAIN PRECIPITATION ACROSS THE SOUTHEAST PLAINS
THROUGH THE MORNING HOURS. THIS LEADS TO LOWER CONFIDENCE IN QPF
FORECAST TODAY AS MODELS PLAY CATCH UP WITH WHAT IS CURRENTLY GOING
ON.
IN WV PICS...APPEARS MAIN SHORTWAVE WHICH HELPED FIRE OFF
YESTERDAY`S CONVECTION HAS ALREADY PUSHED EAST OF THE AREA INTO
CENTRAL KS. HOWEVER...ANOTHER SHORTWAVE IS EVIDENT IN THE MOISTURE
PLUME ACROSS NW CO/SRN WY...WHICH WILL BE TRANSLATING SLOWLY
EASTWARD THROUGH THE UPPER RIDGE ACROSS THE AREA TODAY. AT THE
SFC...DEW POINTS HAVE INCREASED ACROSS THE PLAINS WITH READINGS
MAINLY IN THE 50S. STRATUS IS NOT AS WIDESPREAD AS MODELS
PORTRAYED...PROBABLY A RESULT OF THEIR OVERZEALOUS QPF FORECAST THIS
MORNING. SUSPECT WE WILL SEE SOME STRATUS DEVELOP AND SPREAD
WESTWARD INTO SOUTHEAST PLAINS TOWARDS DAWN BUT IT WILL PROBABLY BE
FAIRLY SHALLOW AND MORE PATCHY IN NATURE EXCEPT ACROSS THE SE CORNER
WHERE IT MAY BE MORE WIDESPREAD. THUS ANY STRATUS WILL LIKELY BURN
OFF FAIRLY QUICKLY THIS MORNING. WITH MORE CLEARING THIS
AFTERNOON...WE WILL BE MORE LIKELY TO SEE SUFFICIENT HEATING TO
TRIGGER ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE SOUTHEAST MOUNTAINS AND ADJACENT PLAINS. WITH LOW LEVEL FLOW
REMAINING EASTERLY...DEW POINTS SHOULD REMAIN IN THE 50S ACROSS THE
PLAINS/I-25 CORRIDOR. THIS WILL LEAD TO CAPE VALUES GENERALLY
BETWEEN 500-1000 J/KG...NOT TERRIBLY HIGH...BUT SUFFICIENT TO
PRODUCE A FEW STRONG STORMS. THUS GREATEST CONCERN WILL BE THE EL
PASO/TELLER COUNTY AREAS WHERE THE SUSCEPTIBLE BURN SCARS WILL BE
UNDER THE GUN FOR MORE HEAVY RAINFALL TODAY. ALTHOUGH NAM12 HAS
TAMED DOWN ITS QPF FCST FOR TODAY VS YESTERDAY`S RUNS...OTHER MODELS
SUCH AS GFS...HIGH RES WRF (LOCAL AND NSSL)AND HRRR BOTH HIT
PORTIONS OF THE SE MTS/ADJACENT PLAINS WITH POCKETS OF HEAVY
RAINFALL. WITH THE SATURATED GROUND FROM RECENT RAINS ACROSS TELLER
AND EL PASO COUNTY...WILL BE PUTTING OUT ANOTHER FLASH FLOOD WATCH
FOR TODAY. GREATEST THREAT WINDOW APPEARS TO BE FROM 2 PM TO 6 PM
FOR THE BURN SCARS THOUGH HRRR SEEMS TO BE TRENDING IT TOWARDS 1 PM
IN SOME OF ITS LATER RUNS. OF COURSE IF THE STRONGER STORMS PASS
AROUND THE BURN SCARS...THEN IT IS POSSIBLE THAT FLASH FLOODING WILL
NOT OCCUR...BUT WILL ERR ON THE SIDE OF CAUTION AS THE PROBABILITY
WILL BE THERE FOR A HIGH IMPACT EVENT SHOULD THE BURN SCARS BE
IMPACTED. THE CITY OF COLORADO SPRINGS COULD ALSO BE UNDER THE GUN
TODAY FOR FLASH FLOODING DUE TO THE SATURATED GROUND FROM
YESTERDAY`S HEAVY RAIN WHICH WILL EXACERBATE ANY RUNOFF TODAY SHOULD
STORMS HIT THAT REGION.
THUNDERSTORMS SHOULD SPREAD EASTWARD ACROSS THE PLAINS DURING THE
LATE AFTERNOON AND EVENING HOURS AS THE SHORTWAVE SLOWLY KICKS
THROUGH THE REGION. WILL DECREASE POPS QUICKLY AFTER 06Z AS
CONSENSUS OF THE MODELS IS TO KEEP CONVECTION GOING WELL TO THE
SOUTH ALONG FRONTAL BOUNDARY ACROSS EASTERN NM/SRN TX PANHANDLE.
GFS SEEMS TO BE THE OUTLIER IN KEEPING WIDESPREAD QPF ACROSS THE
PLAINS THROUGH 12Z...SO WILL DISCOUNT IT FOR NOW. STRATUS SHOULD BE
MORE WIDESPREAD ACROSS THE SE PLAINS TONIGHT.
NOT TO NEGLECT WESTERN AREAS...DRIER AIR OUT THAT WAY SHOULD KEEP
PCPN EFFICIENCIES WITH THUNDERSTORMS LOWER. PRECIP WATERS WILL BE
RUNNING AROUND .50 WHICH PUTS THEM BELOW 100% OF NORMAL. WITH
FORCING FROM THE SHORTWAVE EXPECTED TO IMPACT NORTHERN AREAS MORE SO
THAN THE SOUTHWEST...EXPECT THUNDERSTORMS TO BE MORE ISOLATED TO
SCATTERED IN COVERAGE ACROSS THE EASTERN SAN JUANS AND LA
GARITAS...AND WILL DIMINISH QUICKLY DURING THE EVENING HOURS. THE
WEST FORK BURN SCAR WILL NEED TO BE MONITORED FROM NOON TO 6 PM FOR
POCKETS OF HEAVIER RAIN SUFFICIENT TO CAUSE LOCALIZED
RUNOFF/POTENTIAL FLASH FLOOD PROBLEMS. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 528 AM MDT TUE AUG 13 2013
LONGER TERM METEOROLOGICAL CONCERNS INCLUDE POPS AND TEMPERATURES.
ABOVE SEASONAL POPS IN COMBINATION WITH BELOW SEASONAL TEMPERATURES
ARE EXPECTED FROM WEDNESDAY INTO WEDNESDAY NIGHT AS AVAILABLE
ATMOSPHERIC MOISTURE INTERACTS WITH THE DAILY OROGRAPHIC HEATING
CYCLE AS WELL AS SOME UPPER LIFT.
RECENT LONGER TERM FORECAST MODEL SOUNDINGS INDICATE THAT
LOCATIONS SUCH AS THE I-25 CORRIDOR SHOULD EXPERIENCE PRECIPITABLE
WATER VALUES NEARING ONE INCH AT TIMES WEDNESDAY AFTERNOON.
THE COMBINATION OF AVAILABLE ATMOSPHERIC MOISTURE AND AN
APPROACHING UPPER SHORT-WAVE(PER LATEST GFS40 PV15 FORECAST)
...ESPECIALLY OVER NORTHERN SECTIONS OF THE FORECAST DISTRICT
SHOULD ALLOW FOR ANOTHER ROUND OF ISOLATED TO SCATTERED WEDNESDAY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS OVER THE FORECAST
DISTRICT...ESPECIALLY EASTERN SECTIONS.
ONCE AGAIN...SOME OF THESE STORMS ON WEDNESDAY AFTERNOON AND
EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL AS
WELL AS POTENTIAL BURN SCAR FLOODING ISSUES...ESPECIALLY IF A
STRONGER STORM DEVELOPS OVER A BURN SCAR...SUCH AS THE WALDO
CANYON BURN SCAR...ETC. WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY AND ISSUE HYDRO/FLASH FLOOD HIGHLIGHTS/ADVISORIES/WARNINGS
AS NEEDED.
THEN...WARMER AND DRIER CONDITIONS SHOULD RETURN TO THE FORECAST
DISTRICT FROM LATER THURSDAY INTO AT LEAST EARLY SUNDAY AS AN
UPPER RIDGE BUILDS OVER ARIZONA AND NEW MEXICO. IN ADDITION...
FORECAST PRECIPITABLE WATER VALUES DROP TO BETWEEN 0.50 AND 0.70
INCHES OVER THE INTERSTATE 25 CORRIDOR DURING THIS TIME-FRAME.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
SHOULD BE NOTED OVER THE CWFA FROM LATER THURSDAY INTO EARLY
SUNDAY. EVEN THOUGH RELATIVELY UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM IMPACTS A
BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
IN ADDITION...STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO
DEVELOP OVER PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS FROM
THURSDAY INTO THURSDAY EVENING AS PROJECTED LOCALIZED CAPES/LIS IN
EXCESS OF 2000 J/KG AND -7C RESPECTIVELY INTERACT WITH PROJECTED
0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY IS THEN ANTICIPATED
FROM LATER SUNDAY INTO NEXT TUESDAY AS A NORTHERLY SURFACE SURGE
MOVING ACROSS EASTERN SECTIONS MONDAY INCREASES ATMOSPHERIC
MOISTURE AND INTERACTS WITH UPPER SHORTWAVES. FORECAST MODEL
SOUNDINGS PROJECT THAT PRECIPITABLE WATER VALUES OVER THE
INTERSTATE 25 CORRIDOR INCREASE TO OVER ONE INCH BY MONDAY
AFTERNOON.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR LOCALIZED
HEAVY RAIN AND ASSOCIATED FLASH FLOODING CONCERNS(ESPECIALLY OVER
THE AREA BURN SCARS) WILL BE POSSIBLE FROM LATER SUNDAY INTO NEXT
TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY.
FINALLY...LOW-GRADE GRADIENT WINDS AS WELL AS ABOVE AVERAGE
MID-AUGUST SEASONAL TEMPERATURES ARE ANTICIPATED OVER THE
MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO NEXT MONDAY
WITH THE WARMEST CONDITIONS EXPECTED THIS WEEKEND AS 700 MB
TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB TO AROUND 18C FROM THE
12C READINGS PROJECTED TODAY. MAXIMUM TEMPERATURES THIS WEEKEND
OVER MANY SECTIONS OF THE SOUTHEASTERN COLORADO PLAINS SHOULD
REACH WELL INTO THE 90S BOTH SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 528 AM MDT TUE AUG 13 2013
THERE IS THE POTENTIAL FOR SOME MVFR TO IFR CIGS TO BRIEFLY FORM
OVER KCOS THIS MORNING DUE TO HEAVY RAINFALL FROM YESTERDAY AND
MOIST AIRMASS. DOESN`T APPEAR TO BE A STRONG EASTERLY PUSH OF
THE LOW LEVEL WINDS THOUGH TO HELP GET MORE WIDESPREAD STRATUS TO
DEVELOP...SO THIS IS LIKELY TO REMAIN MORE SPOTTY IN COVERAGE AND
WILL MONITOR LATEST SATELLITE TRENDS FOR THE NEED TO INCLUDE IN
TAF. PLAN TO MAINTAIN SCT012 LAYER UNLESS TRENDS SUGGEST
OTHERWISE. PROBABILITY FOR STRATUS LOOKS LESS LIKELY FOR KPUB BUT
NOT ENTIRELY NIL. SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE
MOUNTAINS AROUND NOON...AND MAY AFFECT THE TAF SITES AFTER 20Z. KCOS
APPEARS TO HAVE THE BEST CHANCE FOR -TSRA THIS AFTERNOON. COULD SEE
SOME BRIEF MVFR/IFR CIGS/VIS WITH THE STRONGER STORMS.
THUNDERSTORMS THREAT SHOULD DIMINISH RAPIDLY AFTER 00Z-01Z WITH A
SLIGHTLY BETTER CHANCE FOR MVFR TO IFR STRATUS TO DEVELOP ALONG THE
I-25 CORRIDOR TOWARDS 12Z WED. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH THIS EVENING FOR
COZ081-084-085.
&&
$$
UPDATE...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
528 AM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM MDT TUE AUG 13 2013
...FLASH FLOOD THREAT FOR BURN SCARS IN EL PASO/TELLER COUNTIES TODAY...
MOST OF SHOWER/TSTORM ACTIVITY HAS DIMINISHED ACROSS THE AREA THIS
MORNING AND MODELS ARE HAVING A DIFFICULT TIME WITH THIS AS BOTH
NAM12 AND GFS MAINTAIN PRECIPITATION ACROSS THE SOUTHEAST PLAINS
THROUGH THE MORNING HOURS. THIS LEADS TO LOWER CONFIDENCE IN QPF
FORECAST TODAY AS MODELS PLAY CATCH UP WITH WHAT IS CURRENTLY GOING
ON.
IN WV PICS...APPEARS MAIN SHORTWAVE WHICH HELPED FIRE OFF
YESTERDAY`S CONVECTION HAS ALREADY PUSHED EAST OF THE AREA INTO
CENTRAL KS. HOWEVER...ANOTHER SHORTWAVE IS EVIDENT IN THE MOISTURE
PLUME ACROSS NW CO/SRN WY...WHICH WILL BE TRANSLATING SLOWLY
EASTWARD THROUGH THE UPPER RIDGE ACROSS THE AREA TODAY. AT THE
SFC...DEW POINTS HAVE INCREASED ACROSS THE PLAINS WITH READINGS
MAINLY IN THE 50S. STRATUS IS NOT AS WIDESPREAD AS MODELS
PORTRAYED...PROBABLY A RESULT OF THEIR OVERZEALOUS QPF FORECAST THIS
MORNING. SUSPECT WE WILL SEE SOME STRATUS DEVELOP AND SPREAD
WESTWARD INTO SOUTHEAST PLAINS TOWARDS DAWN BUT IT WILL PROBABLY BE
FAIRLY SHALLOW AND MORE PATCHY IN NATURE EXCEPT ACROSS THE SE CORNER
WHERE IT MAY BE MORE WIDESPREAD. THUS ANY STRATUS WILL LIKELY BURN
OFF FAIRLY QUICKLY THIS MORNING. WITH MORE CLEARING THIS
AFTERNOON...WE WILL BE MORE LIKELY TO SEE SUFFICIENT HEATING TO
TRIGGER ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE SOUTHEAST MOUNTAINS AND ADJACENT PLAINS. WITH LOW LEVEL FLOW
REMAINING EASTERLY...DEW POINTS SHOULD REMAIN IN THE 50S ACROSS THE
PLAINS/I-25 CORRIDOR. THIS WILL LEAD TO CAPE VALUES GENERALLY
BETWEEN 500-1000 J/KG...NOT TERRIBLY HIGH...BUT SUFFICIENT TO
PRODUCE A FEW STRONG STORMS. THUS GREATEST CONCERN WILL BE THE EL
PASO/TELLER COUNTY AREAS WHERE THE SUSCEPTIBLE BURN SCARS WILL BE
UNDER THE GUN FOR MORE HEAVY RAINFALL TODAY. ALTHOUGH NAM12 HAS
TAMED DOWN ITS QPF FCST FOR TODAY VS YESTERDAY`S RUNS...OTHER MODELS
SUCH AS GFS...HIGH RES WRF (LOCAL AND NSSL)AND HRRR BOTH HIT
PORTIONS OF THE SE MTS/ADJACENT PLAINS WITH POCKETS OF HEAVY
RAINFALL. WITH THE SATURATED GROUND FROM RECENT RAINS ACROSS TELLER
AND EL PASO COUNTY...WILL BE PUTTING OUT ANOTHER FLASH FLOOD WATCH
FOR TODAY. GREATEST THREAT WINDOW APPEARS TO BE FROM 2 PM TO 6 PM
FOR THE BURN SCARS THOUGH HRRR SEEMS TO BE TRENDING IT TOWARDS 1 PM
IN SOME OF ITS LATER RUNS. OF COURSE IF THE STRONGER STORMS PASS
AROUND THE BURN SCARS...THEN IT IS POSSIBLE THAT FLASH FLOODING WILL
NOT OCCUR...BUT WILL ERR ON THE SIDE OF CAUTION AS THE PROBABILITY
WILL BE THERE FOR A HIGH IMPACT EVENT SHOULD THE BURN SCARS BE
IMPACTED. THE CITY OF COLORADO SPRINGS COULD ALSO BE UNDER THE GUN
TODAY FOR FLASH FLOODING DUE TO THE SATURATED GROUND FROM
YESTERDAY`S HEAVY RAIN WHICH WILL EXACERBATE ANY RUNOFF TODAY SHOULD
STORMS HIT THAT REGION.
THUNDERSTORMS SHOULD SPREAD EASTWARD ACROSS THE PLAINS DURING THE
LATE AFTERNOON AND EVENING HOURS AS THE SHORTWAVE SLOWLY KICKS
THROUGH THE REGION. WILL DECREASE POPS QUICKLY AFTER 06Z AS
CONSENSUS OF THE MODELS IS TO KEEP CONVECTION GOING WELL TO THE
SOUTH ALONG FRONTAL BOUNDARY ACROSS EASTERN NM/SRN TX PANHANDLE.
GFS SEEMS TO BE THE OUTLIER IN KEEPING WIDESPREAD QPF ACROSS THE
PLAINS THROUGH 12Z...SO WILL DISCOUNT IT FOR NOW. STRATUS SHOULD BE
MORE WIDESPREAD ACROSS THE SE PLAINS TONIGHT.
NOT TO NEGLECT WESTERN AREAS...DRIER AIR OUT THAT WAY SHOULD KEEP
PCPN EFFICIENCIES WITH THUNDERSTORMS LOWER. PRECIP WATERS WILL BE
RUNNING AROUND .50 WHICH PUTS THEM BELOW 100% OF NORMAL. WITH
FORCING FROM THE SHORTWAVE EXPECTED TO IMPACT NORTHERN AREAS MORE SO
THAN THE SOUTHWEST...EXPECT THUNDERSTORMS TO BE MORE ISOLATED TO
SCATTERED IN COVERAGE ACROSS THE EASTERN SAN JUANS AND LA
GARITAS...AND WILL DIMINISH QUICKLY DURING THE EVENING HOURS. THE
WEST FORK BURN SCAR WILL NEED TO BE MONITORED FROM NOON TO 6 PM FOR
POCKETS OF HEAVIER RAIN SUFFICIENT TO CAUSE LOCALIZED
RUNOFF/POTENTIAL FLASH FLOOD PROBLEMS. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 528 AM MDT TUE AUG 13 2013
LONGER TERM METEOROLOGICAL CONCERNS INCLUDE POPS AND TEMPERATURES.
ABOVE SEASONAL POPS IN COMBINATION WITH BELOW SEASONAL TEMPERATURES
ARE EXPECTED FROM WEDNESDAY INTO WEDNESDAY NIGHT AS AVAILABLE
ATMOSPHERIC MOISTURE INTERACTS WITH THE DAILY OROGRAPHIC HEATING
CYCLE AS WELL AS SOME UPPER LIFT.
RECENT LONGER TERM FORECAST MODEL SOUNDINGS INDICATE THAT
LOCATIONS SUCH AS THE I-25 CORRIDOR SHOULD EXPERIENCE PRECIPITABLE
WATER VALUES NEARING ONE INCH AT TIMES WEDNESDAY AFTERNOON.
THE COMBINATION OF AVAILABLE ATMOSPHERIC MOISTURE AND AN
APPROACHING UPPER SHORT-WAVE(PER LATEST GFS40 PV15 FORECAST)
...ESPECIALLY OVER NORTHERN SECTIONS OF THE FORECAST DISTRICT
SHOULD ALLOW FOR ANOTHER ROUND OF ISOLATED TO SCATTERED WEDNESDAY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS OVER THE FORECAST
DISTRICT...ESPECIALLY EASTERN SECTIONS.
ONCE AGAIN...SOME OF THESE STORMS ON WEDNESDAY AFTERNOON AND
EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL AS
WELL AS POTENTIAL BURN SCAR FLOODING ISSUES...ESPECIALLY IF A
STRONGER STORM DEVELOPS OVER A BURN SCAR...SUCH AS THE WALDO
CANYON BURN SCAR...ETC. WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY AND ISSUE HYDRO/FLASH FLOOD HIGHLIGHTS/ADVISORIES/WARNINGS
AS NEEDED.
THEN...WARMER AND DRIER CONDITIONS SHOULD RETURN TO THE FORECAST
DISTRICT FROM LATER THURSDAY INTO AT LEAST EARLY SUNDAY AS AN
UPPER RIDGE BUILDS OVER ARIZONA AND NEW MEXICO. IN ADDITION...
FORECAST PRECIPITABLE WATER VALUES DROP TO BETWEEN 0.50 AND 0.70
INCHES OVER THE INTERSTATE 25 CORRIDOR DURING THIS TIME-FRAME.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
SHOULD BE NOTED OVER THE CWFA FROM LATER THURSDAY INTO EARLY
SUNDAY. EVEN THOUGH RELATIVELY UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM IMPACTS A
BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
IN ADDITION...STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO
DEVELOP OVER PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS FROM
THURSDAY INTO THURSDAY EVENING AS PROJECTED LOCALIZED CAPES/LIS IN
EXCESS OF 2000 J/KG AND -7C RESPECTIVELY INTERACT WITH PROJECTED
0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY IS THEN ANTICIPATED
FROM LATER SUNDAY INTO NEXT TUESDAY AS A NORTHERLY SURFACE SURGE
MOVING ACROSS EASTERN SECTIONS MONDAY INCREASES ATMOSPHERIC
MOISTURE AND INTERACTS WITH UPPER SHORTWAVES. FORECAST MODEL
SOUNDINGS PROJECT THAT PRECIPITABLE WATER VALUES OVER THE
INTERSTATE 25 CORRIDOR INCREASE TO OVER ONE INCH BY MONDAY
AFTERNOON.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR LOCALIZED
HEAVY RAIN AND ASSOCIATED FLASH FLOODING CONCERNS(ESPECIALLY OVER
THE AREA BURN SCARS) WILL BE POSSIBLE FROM LATER SUNDAY INTO NEXT
TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY.
FINALLY...LOW-GRADE GRADIENT WINDS AS WELL AS ABOVE AVERAGE
MID-AUGUST SEASONAL TEMPERATURES ARE ANTICIPATED OVER THE
MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO NEXT MONDAY
WITH THE WARMEST CONDITIONS EXPECTED THIS WEEKEND AS 700 MB
TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB TO AROUND 18C FROM THE
12C READINGS PROJECTED TODAY. MAXIMUM TEMPERATURES THIS WEEKEND
OVER MANY SECTIONS OF THE SOUTHEASTERN COLORADO PLAINS SHOULD
REACH WELL INTO THE 90S BOTH SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 528 AM MDT TUE AUG 13 2013
THERE IS THE POTENTIAL FOR SOME MVFR TO IFR CIGS TO BRIEFLY FORM
OVER KCOS THIS MORNING DUE TO HEAVY RAINFALL FROM YESTERDAY AND
MOIST AIRMASS. DOESN`T APPEAR TO BE A STRONG EASTERLY PUSH OF
THE LOW LEVEL WINDS THOUGH TO HELP GET MORE WIDESPREAD STRATUS TO
DEVELOP...SO THIS IS LIKELY TO REMAIN MORE SPOTTY IN COVERAGE AND
WILL MONITOR LATEST SATELLITE TRENDS FOR THE NEED TO INCLUDE IN
TAF. PLAN TO MAINTAIN SCT012 LAYER UNLESS TRENDS SUGGEST
OTHERWISE. PROBABILITY FOR STRATUS LOOKS LESS LIKELY FOR KPUB BUT
NOT ENTIRELY NIL. SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE
MOUNTAINS AROUND NOON...AND MAY AFFECT THE TAF SITES AFTER 20Z. KCOS
APPEARS TO HAVE THE BEST CHANCE FOR -TSRA THIS AFTERNOON. COULD SEE
SOME BRIEF MVFR/IFR CIGS/VIS WITH THE STRONGER STORMS.
THUNDERSTORMS THREAT SHOULD DIMINISH RAPIDLY AFTER 00Z-01Z WITH A
SLIGHTLY BETTER CHANCE FOR MVFR TO IFR STRATUS TO DEVELOP ALONG THE
I-25 CORRIDOR TOWARDS 12Z WED. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH THIS EVENING FOR
COZ081-084-085.
&&
$$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
347 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BRING SHOWERS AND EMBEDDED
THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL THROUGH THIS EVENING.
DRY AND SEASONABLE WEATHER RETURNS WEDNESDAY AND CONTINUES INTO
THIS WEEKEND.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
***SHOWERS AND EMBEDDED THUNDERSTORMS MAY BRING LOCALLY HEAVY
RAINFALL/POOR DRAINAGE STREET FLOODING LATE THIS AFTERNOON***
4 PM UPDATE...MUCH OF THE RAIN HAS DISSIPATED OR MOVED OFFSHORE IN
THIS AREA. EXCEPTIONS TO THIS ARE THE CAPE AND ISLANDS WHERE STORMS
ARE MOVING ACROSS NOW. THE STRONGEST OF THESE STORMS REMAIN WELL
SOUTH OF SOUTHERN NEW ENGLAND AND THE OUTER COASTAL WATERS. THAT
SAID...THIS HAS BEEN WELL FORECAST BY THE HRRR MODEL. THE HRRR IS
ALSO ACCURATELY FORECASTING ADDITIONAL SHOWERS AND THUNDERSTORMS IN
NEW YORK STATE JUST AHEAD OF THE COLD FRONT. THESE ARE FORECAST NOT
TO MOVE INTO OUR AREA UNTIL CLOSE TO 00Z...AT WHICH POINT
INSTABILITY IS LIKELY TO BE MORE LIMITED THAN IT ALREADY IS.
HOWEVER...THERE ARE STARTING TO BE SOME INDICATIONS OF CLEARING
ACROSS NEW YORK STATE AND EVEN A BIT INTO THE CONNECTICUT VALLEY IN
MASS AND CONNECTICUT. IF THIS CLEARING CONTINUES...IT MAY PRODUCE
ENOUGH INSTABILITY TO SUSTAIN THESE STORMS.
IF THE STORMS SUSTAIN THEMSELVES...THERE IS POTENTIAL FOR LOCALLY
HEAVY RAINFALL AND POSSIBLY URBAN AND POOR DRAINAGE FLOODING. IN
ADDITION...THE ENVIRONMENT IS THE SAME HIGH SHEAR...LOW CAPE
ENVIRONMENT WE HAVE BEEN IN MUCH OF THE SUMMER. THEREFORE...THERE IS
A POTENTIAL FOR STRONG WINDS WITH THE STRONGEST STORMS.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
TONIGHT...LINGERING SHOWERS SHOULD COME TO AN END SHORTLY AFTER
MIDNIGHT IF NOT BEFORE. THEN CLEARING FROM WEST TO EAST AS THE COLD
FRONT MOVES THROUGH AND DRIER AIR STARTS MOVING IN. TEMPERATURES
OVERNIGHT WILL REMAIN FAIRLY MILD WHILE THE DRY AIR MOVES IN.
WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE STARTS BUILDING INTO
THE REGION. A REASONABLY STRONG LOW LEVEL JET AND DECENT MIXING
WILL RESULT IN GUSTY WINDS DURING THE DAY WHICH WILL PRECLUDE SEA
BREEZES FROM DEVELOPING. OTHERWISE...QUIET WEATHER EXPECTED WITH
BELOW NORMAL TEMPERATURES MORE REMINISCENT OF SEPTEMBER THAN OF MID
AUGUST.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* QUIET...SEASONABLE WEATHER THROUGH THIS WEEKEND
* POSSIBILITY OF SOME RAIN EARLY NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
13/12Z GUIDANCE CONTINUES TO DECENT OVERALL SYNOPTIC AGREEMENT
THROUGH MUCH OF THIS PERIOD.
13/00Z LONG RANGE GUIDANCE CONTINUES TO SHOW QUITE GOOD AGREEMENT
THROUGH MUCH OF THE LONG TERM. INITIAL WEAK MID-LEVEL CUTOFF IS
PROGGED TO MOVE INTO THE CANADIAN MARITIMES...WITH ANOTHER MID-
LEVEL CUTOFF MOVING FROM HUDSON BAY TO SOUTHEAST CANADA TOWARD
THE END OF THIS WEEK. THIS SETS UP A PATTERN WITH A BROAD MID-
LEVEL TROUGH OVER SOUTHEAST CANADA...WITH A WEAKER SOUTHERN
BRANCH OF THE JET STREAM CONVERGING NEAR THE MARITIMES. THE END
RESULT SHOULD BE PERSISTENT RIDGING NEAR OR OVER SOUTHERN NEW
ENGLAND THROUGH MUCH OF THE EXTENDED FORECAST. STAYED CLOSE TO THE
CONSENSUS SOLUTION...UNTIL SOME OF THE FINER DETAILS CAN BE BETTER
RESOLVED.
THURSDAY INTO
AS A SECOND CUTOFF DIVES S FROM HUDSON BAY
IN THE PERSISTENT BROAD TROF OVER ERN CANADA AND THE NORTHEAST
CONUS. HOWEVER...THE LONGWAVE TROF AND THIS SECOND CUTOFF LOOK TO
HAVE LITTLE EFFECT ON THE REGION AS STRONG RIDGING ALONG THE
SOUTHERN HALF OF THE CONUS COMBINES WITH RIDGING IN THE ATLANTIC
TO YIELD SUBSIDENCE AND BROAD SFC HIGH PRES OVER THE NORTHEAST.
GIVEN THERE IS GOOD AGREEMENT BETWEEN BOTH OPERATIONAL MODELS AND
THEIR COUNTERPART ENSEMBLES...HAVE REASONABLY HIGH CONFIDENCE THAT
THIS HIGH PRES WILL YIELD A MOSTLY DRY FORECAST THROUGH EARLY NEXT
WEEK. GIVEN THIS...WILL USE A GFS/ECMWF BLEND AS A BASELINE FOR
THIS FORECAST UPDATE.
TEMPERATURES SHOULD SLOWLY RISE THROUGH THIS PORTION OF THE
FORECAST...BUT REMAIN SEASONABLE. COMFORTABLE HUMIDITY LEVELS
THROUGH FRIDAY...WILL SLOWLY INCREASE THIS WEEKEND INTO EARLY NEXT
WEEK. THERE IS SOME QUESTION AS TO HOW CLOSE A LOW PRESSURE WILL
GET TO OUR REGION EARLY NEXT WEEK. AT THIS JUNCTURE...THINKING IT
WILL REMAIN WELL TO OUR SOUTH...SO KEPT THE FORECAST DRY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE
WEDNESDAY AND WEDNESDAY NIGHT.
THROUGH 00Z...RAIN WITH EMBEDDED THUNDERSTORMS ALONG SOUTH
COAST...CAPE...AND ISLANDS. ISOLD TO SCT SHRA ELSEWHERE. GENERALLY
IFR IN THE MAIN BATCH OF RAIN WITH IFR TO VFR CONDITIONS
ELSEWHERE. IFR CONDITIONS WILL BE MOSTLY DUE TO POCKETS OF
HEAVIER RAIN. EXACT TIMING REMAINS UNCERTAIN.
TONIGHT...LOW PROBABILITY OF A LINE OF SHOWERS AND THUNDERSTORMS
MOVING INTO WESTERN ZONES RIGHT AROUND 00Z. OTHERWISE...MAY SEE
SOME LINGERING LOW CLOUDS AND FOG PATCHES PERSIST AT SOME
/ESPECIALLY EASTERN/ TERMINALS INTO THE OVERNIGHT HOURS. AREAL
COVERAGE OF LOW CLOUDS AND FOG PATCHES ARE UNCERTAIN.
WEDNESDAY...ANY LEFTOVER MVFR-IFR CONDITIONS IN SCATTERED LOW
CLOUDS/FOG PATCHES WILL IMPROVE TO VFR NOT LONG AFTER SUNRISE.
OTHERWISE...VFR CONDITIONS.
WEDNESDAY NIGHT...VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING. MAY SEE BOUNCING BETWEEN VFR AND LOWER CATEGORIES WITH
RAIN THIS EVENING.
KBDL TERMINAL...MODERATE CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING.
OUTLOOK...THURSDAY THROUGH SUNDAY...
HIGH CONFIDENCE VFR. LOW CONFIDENCE FOR IFR IN PATCHY FOG AND LOW
CLOUDS LATE THURSDAY NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN WATERS THIS
AFTERNOON WITH ANOTHER ROUND OF ISOLATED TO SCATTERED STORMS LATE
THIS EVENING. THESE STORMS WILL LIMIT VISIBILITIES. EXPECT
CLEARING LATE TONIGHT WITH FAIRLY QUIET WEATHER WEDNESDAY AND
WEDNESDAY NIGHT. THERE IS POTENTIAL FOR 5 FOOT SEAS AND WESTERLY
WINDS GUSTING TO 25 KTS ON THE OUTER WATERS. WITH THE NICE BOATING
WEATHER EXPECTED...HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE OUTER
WATERS FOR WEDNESDAY AND WEDNESDAY NIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. WINDS WILL SHIFT
DIRECTION AS A HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND AND
THE WATERS BUT WILL REMAIN BELOW 20 KTS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 5 AM EDT THURSDAY
FOR ANZ250-254>256.
&&
$$
SYNOPSIS...RLG/BELK
NEAR TERM...RLG
SHORT TERM...RLG
LONG TERM...BELK
AVIATION...RLG/BELK
MARINE...RLG/BELK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
203 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BRING SHOWERS AND EMBEDDED
THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL THROUGH THIS EVENING.
DRY AND SEASONABLE WEATHER RETURNS WEDNESDAY AND CONTINUES INTO
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
***SHOWERS AND EMBEDDED THUNDERSTORMS MAY BRING LOCALLY HEAVY
RAINFALL/POOR DRAINAGE STREET FLOODING LATE THIS AFTERNOON***
2 PM UPDATE...MUCH OF THE RAIN HAS DISSIPATED OR MOVED OFFSHORE IN
THIS AREA. EXCEPTIONS TO THIS ARE SOUTHERN RHODE ISLAND AND
SOUTHEASTERN MASSACHUSETTS INCLUDING THE CAPE AND ISLANDS WHERE
STORMS MOVING NORTHEASTWARD FROM NEW JERSEY ARE TRACKING. THE
STRONGEST OF THESE STORMS REMAIN WELL SOUTH OF SOUTHERN NEW
ENGLAND...POSSIBLY ONLY CLIPPING THE SOUTHERN OUTER COASTAL
WATERS. THAT SAID...THIS IS VERY SIMILAR TO THE HRRR MODEL THAT
FORECASTS ADDITIONAL SHOWERS AND THUNDERSTORMS FORMING IN NEW YORK
STATE JUST AHEAD OF THE COLD FRONT. THESE STORMS HAVE DEVELOPED
JUST EAST OF LAKE ONTARIO SOUTHWARD INTO CENTRAL PENNSYLVANIA AND
WILL SLOWLY MAKE THEIR WAY EASTWARD. THESE ARE FORECAST NOT TO MOVE
INTO OUR AREA UNTIL CLOSE TO 00Z...AT WHICH POINT INSTABILITY IS
LIKELY TO BE MORE LIMITED THAN IT ALREADY IS. HOWEVER...THERE ARE
STARTING TO BE SOME INDICATIONS OF CLEARING ACROSS NEW YORK STATE
AND EVEN A BIT INTO THE CONNECTICUT VALLEY IN MASS AND
CONNECTICUT. IF THIS CLEARING CONTINUES...IT MAY PRODUCE ENOUGH
INSTABILITY TO SUSTAIN THESE STORMS.
IF THE STORMS SUSTAIN THEMSELVES...THERE IS GOOD POTENTIAL FOR
LOCALLY HEAVY RAINFALL AND POSSIBLY URBAN AND POOR DRAINAGE
FLOODING. IN ADDITION...THE ENVIRONMENT IS THE SAME HIGH
SHEAR...LOW CAPE ENVIRONMENT WE HAVE BEEN IN MUCH OF THE SUMMER.
THEREFORE...THERE IS A POTENTIAL FOR STRONG WINDS WITH THE
STRONGEST STORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
TONIGHT...
A FEW SHOWERS AND ISOLATED THUNDERSTORMS MAY LINGER DURING THE
EVENING ESPECIALLY ALONG THE COAST. OTHERWISE...MUCH DRIER MID
LEVEL AIR WILL WORK INTO THE REGION BY LATE EVENING BRINGING AN END
TO MOST OF THE PRECIPITATION. MAY SEE SOME PATCHY GROUND FOG
DEVELOP IN THE TYPICALLY PRONE LOCATIONS...ESPECIALLY IN AREAS THAT
SEE A FAIR AMOUNT OF RAIN TODAY. LOW TEMPS WILL MAINLY BE IN THE
UPPER 50S AND LOWER 60S.
WEDNESDAY...
A MIXTURE OF CLOUDS/SUN ALONG WITH GUSTY NORTHWEST WINDS BEHIND THE
COLD FRONT ON WED. LOW RISK OF A BRIEF SPRINKLE/SPOT SHOWER ACROSS
OUR FAR NORTHWEST ZONES...BUT BASICALLY A DRY AND BEAUTIFUL DAY
EXPECTED FOR THE MIDDLE OF AUGUST. HIGH TEMPS WILL MAINLY BE IN THE
70S WITH LOW HUMIDITY. IN FACT...SOME OF THE HIGHEST TERRAIN WILL
STRUGGLE TO REACH 70!
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* QUIET...SEASONABLE WEATHER WED THRU THE WEEKEND
* POSSIBILITY OF SOME RAIN EARLY NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
13/00Z LONG RANGE GUIDANCE CONTINUES TO SHOW QUITE GOOD AGREEMENT
THROUGH MUCH OF THE LONG TERM. INITIAL WEAK CUTOFF IS PROGGED TO
SLIDE INTO THE CANADIAN MARITIMES AS A SECOND CUTOFF DIVES S FROM
HUDSON BAY IN THE PERSISTENT BROAD TROF OVER ERN CANADA AND THE
NORTHEAST CONUS. HOWEVER...THE LONGWAVE TROF AND THIS SECOND
CUTOFF LOOK TO HAVE LITTLE EFFECT ON THE REGION AS STRONG RIDGING
ALONG THE SOUTHERN HALF OF THE CONUS COMBINES WITH RIDGING IN THE
ATLANTIC TO YIELD SUBSIDENCE AND BROAD SFC HIGH PRES OVER THE
NORTHEAST. GIVEN THERE IS GOOD AGREEMENT BETWEEN BOTH OPERATIONAL
MODELS AND THEIR COUNTERPART ENSEMBLES...HAVE REASONABLY HIGH
CONFIDENCE THAT THIS HIGH PRES WILL YIELD A MOSTLY DRY FORECAST
THROUGH EARLY NEXT WEEK. GIVEN THIS...WILL USE A GFS/ECWMF BLEND
AS A BASELINE FOR THIS FORECAST UPDATE.
WED NIGHT INTO FRI...
HIGH PRES GRADUALLY SLIDES IN FROM THE W THROUGH THE PERIOD. WITH
THE HIGH PRES CENTER REMAINING W OF THE REGION...EXPECT US TO
REMAIN ON THE COOLER SIDE OF THE HIGH INITIALLY. H85 TEMPS RANGE
BETWEEN +8C AND ABOUT +11C...SO HIGHS SHOULD START THU AROUND THE
MID 70S...INCREASING TO THE UPPER 70S AND LOW 80S BY FRI AFTER
SOME AIRMASS MODIFICATION. OVERNIGHT MINS WILL BE ON THE COOL SIDE
WITH LOW HUMIDITY /AND THEREFORE LOW DWPTS/ WITH LIGHT FLOW AND
CLEAR SKIES. EXPECTING MINS DIPPING AS LOW AS THE MID 40S IN
NORMALLY COOLER SPOTS. MID 50S IN THE WARMER SPOTS.
THIS COMING WEEKEND...
A WARM FRONT IS EXPECTED TO BEGIN A GRADUAL SLIDE TO THE N
THROUGH THE WEEKEND...BUT WITH HIGH PRES IN PLACE OVER THE REGION
AND VERY SLOWLY SLIDING TO THE E...EXPECTING MOSTLY DRY CONDITIONS
ACROSS SRN NEW ENGLAND DESPITE THIS APPROACHING FRONT. GFS
CURRENTLY SUGGESTS HIGHEST POTENTIAL FOR SOME PRECIP...BUT IT TOO
KEEPS MOST OF ITS GENERATED QPF TO THE W. MID LVL TEMPS DO
INCREASE SOMEWHAT...REACHING +10 TO +13C...SO TEMPS LEAN NEAR TO
SLIGHTLY WARMER THAN NORMAL.
EARLY NEXT WEEK...
DIFFERENCES IN THE TIMING OF A STRONGER SHORTWAVE EFFECTING THE
REGION GIVES WAY TO LOWER CONFIDENCE HERE...BUT IT APPEARS THAT
THERE WILL BE A BIT HIGHER CHANCE FOR SOME PRECIP PARTICULARLY BY
TUE. WILL BE INCREASING TO SOME SLIGHT CHANCE POPS...CLOSER TO THE
ECWMF SOLUTION...WHICH SUGGESTS THE WARM FRONT LIFTS FAR ENOUGH N
TO AFFECT THE REGION WITH THIS SHORTWAVE PASSAGE.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE
WEDNESDAY AND WEDNESDAY NIGHT.
THROUGH 00Z...RAIN WITH EMBEDDED THUNDERSTORMS ALONG SOUTH
COAST...CAPE...AND ISLANDS. ISOLD TO SCT SHRA ELSEWHERE. GENERALLY
IFR IN THE MAIN BATCH OF RAIN WITH IFR TO VFR CONDITIONS
ELSEWHERE. IFR CONDITIONS WILL BE MOSTLY DUE TO POCKETS OF
HEAVIER RAIN. EXACT TIMING REMAINS UNCERTAIN.
TONIGHT...LOW PROBABILITY OF A LINE OF SHOWERS AND THUNDERSTORMS
MOVING INTO WESTERN ZONES RIGHT AROUND 00Z. OTHERWISE...MAY SEE
SOME LINGERING LOW CLOUDS AND FOG PATCHES PERSIST AT SOME
/ESPECIALLY EASTERN/ TERMINALS INTO THE OVERNIGHT HOURS. AREAL
COVERAGE OF LOW CLOUDS AND FOG PATCHES ARE UNCERTAIN.
WEDNESDAY...ANY LEFTOVER MVFR-IFR CONDITIONS IN SCATTERED LOW
CLOUDS/FOG PATCHES WILL IMPROVE TO VFR NOT LONG AFTER SUNRISE.
OTHERWISE...VFR CONDITIONS.
WEDNESDAY NIGHT...VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING. MAY SEE BOUNCING BETWEEN VFR AND LOWER CATEGORIES WITH
RAIN THIS EVENING.
KBDL TERMINAL...MODERATE CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING.
OUTLOOK...THURSDAY THROUGH SATURDAY...
HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY AND TONIGHT...HIGH CONFIDENCE. WINDS AND SEAS WILL REMAIN
BELOW SCA THRESHOLDS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE. THE MAIN CONCERN EARLY THIS MORNING WILL BE FOR DENSE FOG
ACROSS OUR SOUTHERN WATERS. THIS FOG SHOULD BURN OFF TO AT LEAST
SOME DEGREE BY MID TO LATE MORNING. THE OTHER CONCERN WILL BE FOR
EMBEDDED THUNDERSTORMS TO WORK ACROSS THE WATERS...MAINLY THIS
AFTERNOON AND EVENING.
WEDNESDAY...MODERATE CONFIDENCE. NORTHWEST WIND GUSTS OF 25 KNOTS
ARE EXPECTED NEAR SHORE WITH GOOD MIXING BEHIND THE COLD FRONT. ITS
3RD PERIOD SO DID NOT GO WITH ANY HEADLINES AT THIS POINT...BUT
LATER SHIFTS MAY NEED TO CONSIDER A SCA FOR SOME OF OUR NEAR SHORE
WATERS. MAY ALSO SEE SOME 3 TO 5 FOOT SEAS DEVELOP ACROSS OUR
SOUTHERN MOST ATLANTIC WATERS...WHICH MAY ALSO NEED TO BE CONSIDERED
FOR HEADLINES.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. WINDS WILL SHIFT
DIRECTION AS HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND AND THE
WATERS BUT WILL REMAIN BELOW 25 KTS...SAVE FOR POSSIBLY WED
EVENING.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY/RLG
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY/RLG
MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION
NWS ALBANY NY
145 PM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS AFTERNOON WITH
ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM. IN ITS WAKE...COOLER
AND LESS HUMID AIR WILL RETURN TO THE REGION FOR TOMORROW. THROUGH
THE REMAINDER OF THE WEEK...HIGH PRESSURE WILL ALLOW FOR DRY
CONDITIONS...WITH TEMPERATURES SLOWLY MODERATING BACK TOWARDS NORMAL
LEVELS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM EDT...WE HAD A PRETTY HEAVY BATCH OF RAIN (WITH
EMBEDDED THUNDERSTORMS) MOVE THROUGH PORTIONS OF THE REGION...WITH
THE HEAVIEST RAINFALL FALLING TO THE EAST OF THE CAPITAL DISTRICT
WHERE RAINFALL ESTIMATED APPROACHING TWO INCHES. PLEASE REFER TO OUR
LATEST PUBLIC WEATHER STATEMENTS (PNS) FOR ALL THE LATEST RAINFALL
REPORTS.
THIS BATCH OF RAIN HAS MOSTLY MOVED TO THE EAST OF THE HUDSON
VALLEY..WITH SOME POCKETS OF MODERATE TO HEAVY RAINFALL IN DUTCHESS
COUNTY AS WELL AS PORTIONS OF SOUTHERN VERMONT. THERE WERE WIDELY
SCATTERED LIGHT SHOWERS STILL AROUND MAINLY ACROSS THE MOHAWK VALLEY.
HOWEVER...ANOTHER LINE OF SHOWERS WERE DEVELOPING RIGHT AHEAD OF THE
COLD FRONT...LOCATED IN CENTRAL NEW YORK. THE HRRR AND HIRESWRF BOTH
HAVE THIS LINE OF SHOWERS COMING THROUGH. FOR ONCE...THESE MODELS
HAVE APPEARED TO DONE FAIRLY WELL WITH THE EVOLUTION OF THE RAINFALL
THUS FAR. THEREFORE...WILL LEAN WITH ITS SOLUTION OF BRINGING
ANOTHER LINE OF NUMEROUS SHOWERS OUR WAY THIS AFTERNOON. THIS LINE
LOOKS TO MOVE THROUGH BETWEEN ABOUT 100 PM (NORTHWEST) TO ABOUT 800
PM (SOUTHEAST). WINDS OFF THE DECK LOOK TO BACK TO THE SOUTHEAST
WILL WOULD HELP ENHANCED CONVERGENCE AND UPWARD MOTION WITH THE
FRONT.
INSTABILITY IS VERY LIMITED...GENERALLY UNDER 1000/J SO AT THIS
TIME...WE ARE FAIRLY CONFIDENT THERE WILL BE NO SEVERE OR EVEN
STRONG THUNDERSTORM ACTIVITY. ONE THING TO NOTE...THERE IS SOME
PRETTY LOW LEVEL WIND WITH THE LOWER WINDS SSE BECOMING WSW QUICKLY
AS ONE GOES THROUGH NEAR THE GROUND THROUGH ABOUT 5000 FEET. THERE
COULD BE SOME WEAK LOW LEVEL ROTATION BUT AGAIN WITH VERY LIMITED
INSTABILITY NOTHING ELSE IS EXPECTED...OTHER THAN PERHAPS A LITTLE
MORE HEAVY RAINFALL.
MAX TEMPS LOOK TO BE THE HELD IN THE LOW TO MID 70S TODAY. TEMPS
WILL ONLY REACH THE UPPER 60S ACROSS THE HIGHEST TERRAIN.
THE FRONT WILL CROSS DURING THE EARLY EVENING HOURS. THIS WILL BRING
AN END TO THE RAIN SHOWERS. SOME LINGERING SHOWERS ARE POSSIBLE
ACROSS NORTHERN AREAS TONIGHT AS THE UPPER TROUGH APPROACHES AND
PASSES JUST TO THE NORTH. WITH COOLER AIR STARTING TO MOVE IN BEHIND
THE COLD FRONT...MIN TEMPS WILL DROP INTO THE 50S OVERNIGHT AND
DEWPOINTS WILL FALL DURING THE OVERNIGHT HOURS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE OHIO VALLEY FOR
THE ENTIRE SHORT TERM PERIOD. IT LOOKS TO BE MAINLY DRY ACROSS
THE REGION WITH COMFORTABLE HUMIDITY LEVELS AND BELOW NORMAL
TEMPERATURES. THE EXCEPTION TO THE DRY WEATHER WILL BE DURING THE
DAY ON WEDNESDAY ACROSS THE ADKS...WHERE COOL TEMPS ALOFT WILL
ALLOW FOR THE FORMATION OF SOME SCATTERED LIGHT RAIN SHOWERS.
MAX TEMPS ON WED AND THURSDAY WILL BE IN THE LOW TO MID 70S FOR
VALLEY AREAS /60 ACROSS THE HIGH TERRAIN. MIN TEMPS WILL GENERALLY
BE IN THE LOW 50S /40S FOR THE HIGH TERRAIN AND OUTLYING AREAS/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
DRY AND TRANQUIL WEATHER IS EXPECTED FOR THE PERIOD. RIDGING IS
EXPECTED TO DOMINATE AT THE SURFACE WITH HEIGHTS ALOFT GRADUALLY
RISING WITH RIDGING BUILDING IN ACROSS THE WESTERN ATLANTIC.
A WAVE OF LOW PRESSURE IS EXPECTED TO MOVE EASTWARD ALONG A STALLED
FRONTAL BOUNDARY ACROSS THE SOUTHEASTERN UNITED STATES. THE BOUNDARY
IS EXPECTED TO SHIFT NORTHWARD OVER THE WEEKEND. HOWEVER IT APPEARS
PRECIPITATION ASSOCIATED WITH THIS FEATURE SHOULD REMAIN TO OUR
SOUTH...SO LOOKING AT DRY WEATHER THROUGH THE WEEKEND INTO EARLY
NEXT WEEK.
SEASONABLE TEMPERATURES ARE EXPECTED WITH HIGHS MAINLY IN THE MID
70S TO LOWER 80S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
MOST OF THE RAIN HAS MOVED EAST OF THE TAF SITES. STILL SOME
PATCHES OF LIGHT RAIN...ONE OVER KGFL AND ONE OVER KPOU.
CONDITIONS SHOULD GRADUALLY IMPROVE OVER THE NEXT COUPLE OF HOURS
BEFORE ANOTHER ROUND OF SHOWERS AND POSSIBLY A THUNDERSTORM ARRIVE
AHEAD OF THE COLD FRONT. DO NOT HAVE THUNDERSTORMS SPECIFICALLY
MENTIONED IN TAFS AT TIME. NOT MANY LIGHTNING STIKES UPSTREAM. LATER
SHIFTS WILL MONITOR AND AMEND AS NECESSARY. CONDITIONS SHOULD
IMPROVE TO VFR FOR A PERIOD THIS EVENING INTO THE
OVERNIGHT...HOWEVER A RETURN TO MVFR IS ANTICIPATED WITH IFR
POSSIBLE AT KGFL AND KPSF.
LIGHT SOUTHERLY WINDS WILL SHIFT TO THE WEST AND NORTHWEST WITH THE
PASSAGE OF THE COLD FRONT THIS EVENING. WINDS WILL BE STRONG AND
GUSTY FROM THE NORTHWEST ON WEDNESDAY...GUSTING TO 25 KNOTS.
OUTLOOK...
WED-SAT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES EXPECTED OVER THE NEXT FEW DAYS.
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A FRONTAL BOUNDARY IS
EXPECTED TODAY. RAINFALL AMOUNTS LOOK TO AVERAGE AROUND ONE HALF
INCH...LOCALLY OVER AN INCH WHERE HEAVIER SHOWERS OR
THUNDERSTORMS TAKE PLACE. THIS WILL BRING A WETTING RAIN TO THE
REGION.
RH VALUES WILL ONLY DROP TO 70 TO 80 PERCENT TODAY DUE TO CLOUDS AND
RAIN. THEY WILL BE NEAR 100 PERCENT TONIGHT AND DROP TO AROUND 40
TO 60 PERCENT TOMORROW AFTERNOON.
LARGE CANADIAN HIGH PRESSURE LOOKS TO TAKE CONTROL OF OUR WEATHER
WEDNESDAY THROUGH AT LEAST FRIDAY WITH DRY WEATHER.
&&
.HYDROLOGY...
AN APPROACHING FRONTAL BOUNDARY WILL BRING A ROUND OF RAIN SHOWERS
AND POSSIBLE THUNDERSTORMS TO THE REGION TODAY. PWAT VALUES WILL RISE
TO AROUND 1.50-1.75 INCHES INCHES AHEAD OF THE FRONTAL BOUNDARY.
WHILE ANY SHOWER OR THUNDERSTORM WILL BE CAPABLE OF HEAVY
DOWNPOURS...THE ATMOSPHERE IS NOT QUITE AS MOIST AS LATE LAST WEEK
WHEN SOME FLASH FLOODING OCCURRED ACROSS THE MID HUDSON VALLEY AND
NW CT. IN ADDITION...STRONG FLOW ALOFT SHOULD KEEP ANY SHOWERS OR
THUNDERSTORMS MOVING RATHER QUICKLY. AS A RESULT...FLASH FLOODING
IS NOT ANTICIPATED WITH THIS STORM SYSTEM. SOME MINOR RISES WILL
BE POSSIBLE ON AREA RIVERS AND STREAMS...ESPECIALLY ACROSS THOSE
AREAS THAT SAW HEAVIER RAIN LAST WEEK. THERE STILL COULD BE
PONDING ON ROADWAYS AND AREAS OF POOR DRAINAGE THROUGH TUESDAY
EVENING.
DRY WEATHER WILL RETURN BY LATE TONIGHT AND CONTINUE THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER AND STREAMS LEVELS TO
RECEDE ONCE MORE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...SND/HWJIV
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...SND
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1230 PM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS AFTERNOON WITH
ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM. IN ITS WAKE...COOLER
AND LESS HUMID AIR WILL RETURN TO THE REGION FOR TOMORROW. THROUGH
THE REMAINDER OF THE WEEK...HIGH PRESSURE WILL ALLOW FOR DRY
CONDITIONS...WITH TEMPERATURES SLOWLY MODERATING BACK TOWARDS NORMAL
LEVELS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM EDT...WE HAD A PRETTY HEAVY BATCH OF RAIN (WITH
EMBEDDED THUNDERSTORMS) MOVE THROUGH PORTIONS OF THE REGION...WITH
THE HEAVIEST RAINFALL FALLING TO THE EAST OF THE CAPITAL DISTRICT
WHERE RAINFALL ESTIMATED APPROACHING TWO INCHES. PLEASE REFER TO OUR
LATEST PUBLIC WEATHER STATEMENTS (PNS) FOR ALL THE LATEST RAINFALL
REPORTS.
THIS BATCH OF RAIN HAS MOSTLY MOVED TO THE EAST OF THE HUDSON
VALLEY..WITH SOME POCKETS OF MODERATE TO HEAVY RAINFALL IN DUTCHESS
COUNTY AS WELL AS PORTIONS OF SOUTHERN VERMONT. THERE WERE WIDELY
SCATTERED LIGHT SHOWERS STILL AROUND MAINLY ACROSS THE MOHAWK VALLEY.
HOWEVER...ANOTHER LINE OF SHOWERS WERE DEVELOPING RIGHT AHEAD OF THE
COLD FRONT...LOCATED IN CENTRAL NEW YORK. THE HRRR AND HIRESWRF BOTH
HAVE THIS LINE OF SHOWERS COMING THROUGH. FOR ONCE...THESE MODELS
HAVE APPEARED TO DONE FAIRLY WELL WITH THE EVOLUTION OF THE RAINFALL
THUS FAR. THEREFORE...WILL LEAN WITH ITS SOLUTION OF BRINGING
ANOTHER LINE OF NUMEROUS SHOWERS OUR WAY THIS AFTERNOON. THIS LINE
LOOKS TO MOVE THROUGH BETWEEN ABOUT 100 PM (NORTHWEST) TO ABOUT 800
PM (SOUTHEAST). WINDS OFF THE DECK LOOK TO BACK TO THE SOUTHEAST
WILL WOULD HELP ENHANCED CONVERGENCE AND UPWARD MOTION WITH THE
FRONT.
INSTABILITY IS VERY LIMITED...GENERALLY UNDER 1000/J SO AT THIS
TIME...WE ARE FAIRLY CONFIDENT THERE WILL BE NO SEVERE OR EVEN
STRONG THUNDERSTORM ACTIVITY. ONE THING TO NOTE...THERE IS SOME
PRETTY LOW LEVEL WIND WITH THE LOWER WINDS SSE BECOMING WSW QUICKLY
AS ONE GOES THROUGH NEAR THE GROUND THROUGH ABOUT 5000 FEET. THERE
COULD BE SOME WEAK LOW LEVEL ROTATION BUT AGAIN WITH VERY LIMITED
INSTABILITY NOTHING ELSE IS EXPECTED...OTHER THAN PERHAPS A LITTLE
MORE HEAVY RAINFALL.
MAX TEMPS LOOK TO BE THE HELD IN THE LOW TO MID 70S TODAY. TEMPS
WILL ONLY REACH THE UPPER 60S ACROSS THE HIGHEST TERRAIN.
THE FRONT WILL CROSS DURING THE EARLY EVENING HOURS. THIS WILL BRING
AN END TO THE RAIN SHOWERS. SOME LINGERING SHOWERS ARE POSSIBLE
ACROSS NORTHERN AREAS TONIGHT AS THE UPPER TROUGH APPROACHES AND
PASSES JUST TO THE NORTH. WITH COOLER AIR STARTING TO MOVE IN BEHIND
THE COLD FRONT...MIN TEMPS WILL DROP INTO THE 50S OVERNIGHT AND
DEWPOINTS WILL FALL DURING THE OVERNIGHT HOURS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE OHIO VALLEY FOR
THE ENTIRE SHORT TERM PERIOD. IT LOOKS TO BE MAINLY DRY ACROSS
THE REGION WITH COMFORTABLE HUMIDITY LEVELS AND BELOW NORMAL
TEMPERATURES. THE EXCEPTION TO THE DRY WEATHER WILL BE DURING THE
DAY ON WEDNESDAY ACROSS THE ADKS...WHERE COOL TEMPS ALOFT WILL
ALLOW FOR THE FORMATION OF SOME SCATTERED LIGHT RAIN SHOWERS.
MAX TEMPS ON WED AND THURSDAY WILL BE IN THE LOW TO MID 70S FOR
VALLEY AREAS /60 ACROSS THE HIGH TERRAIN. MIN TEMPS WILL GENERALLY
BE IN THE LOW 50S /40S FOR THE HIGH TERRAIN AND OUTLYING AREAS/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
DRY AND TRANQUIL WEATHER IS EXPECTED FOR THE PERIOD. RIDGING IS
EXPECTED TO DOMINATE AT THE SURFACE WITH HEIGHTS ALOFT GRADUALLY
RISING WITH RIDGING BUILDING IN ACROSS THE WESTERN ATLANTIC.
A WAVE OF LOW PRESSURE IS EXPECTED TO MOVE EASTWARD ALONG A STALLED
FRONTAL BOUNDARY ACROSS THE SOUTHEASTERN UNITED STATES. THE BOUNDARY
IS EXPECTED TO SHIFT NORTHWARD OVER THE WEEKEND. HOWEVER IT APPEARS
PRECIPITATION ASSOCIATED WITH THIS FEATURE SHOULD REMAIN TO OUR
SOUTH...SO LOOKING AT DRY WEATHER THROUGH THE WEEKEND INTO EARLY
NEXT WEEK.
SEASONABLE TEMPERATURES ARE EXPECTED WITH HIGHS MAINLY IN THE MID
70S TO LOWER 80S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHOWERS AND SCATTERED THUNDERSTORMS WILL CONTINUE TO OVERSPREAD THE
AREA THIS MORNING WITH MVFR CONDITIONS DEVELOPING. DYNAMICS WITH
THIS SYSTEM ARE STRONG ENOUGH THAT AN AREA OF LOW PRESSURE HAS
FORMED OVER THE SAINT LAWRENCE RIVER VALLEY WITH A SECONDARY AREA OF
LOW PRESSURE OVER DELMARVA. BOTH LOWS WILL MOVE NORTHEASTWARD
EVENTUALLY CONSOLIDATED INTO ONE LOW OVER NEW ENGLAND LATE TONIGHT.
HAVE ADDRESSED THREAT FOR HEAVIER CONVECTION WITH A TEMPO GROUP WITH
IFR CONDITIONS. DO NOT HAVE THUNDERSTORMS SPECIFICALLY MENTIONED IN
TAFS AT TIME. CONVECTION WILL TAPER OFF LATE THIS AFTERNOON INTO THE
EVENING. CONDITIONS SHOULD IMPROVE TO VFR FOR A PERIOD THIS EVENING
INTO THE OVERNIGHT...HOWEVER A RETURN TO MVFR IS ANTICIPATED WITH
IFR POSSIBLE AT KGFL AND KPSF.
LIGHT SOUTHERLY WINDS WILL SHIFT TO THE WEST WITH THE PASSAGE OF THE
LOWS AND FRONTAL BOUNDARY.
OUTLOOK...
WED-SAT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES EXPECTED OVER THE NEXT FEW DAYS.
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A FRONTAL BOUNDARY IS
EXPECTED TODAY. RAINFALL AMOUNTS LOOK TO AVERAGE AROUND ONE HALF
INCH...LOCALLY OVER AN INCH WHERE HEAVIER SHOWERS OR
THUNDERSTORMS TAKE PLACE. THIS WILL BRING A WETTING RAIN TO THE
REGION.
RH VALUES WILL ONLY DROP TO 70 TO 80 PERCENT TODAY DUE TO CLOUDS AND
RAIN. THEY WILL BE NEAR 100 PERCENT TONIGHT AND DROP TO AROUND 40
TO 60 PERCENT TOMORROW AFTERNOON.
LARGE CANADIAN HIGH PRESSURE LOOKS TO TAKE CONTROL OF OUR WEATHER
WEDNESDAY THROUGH AT LEAST FRIDAY WITH DRY WEATHER.
&&
.HYDROLOGY...
AN APPROACHING FRONTAL BOUNDARY WILL BRING A ROUND OF RAIN SHOWERS
AND POSSIBLE THUNDERSTORMS TO THE REGION TODAY. PWAT VALUES WILL RISE
TO AROUND 1.50-1.75 INCHES INCHES AHEAD OF THE FRONTAL BOUNDARY.
WHILE ANY SHOWER OR THUNDERSTORM WILL BE CAPABLE OF HEAVY
DOWNPOURS...THE ATMOSPHERE IS NOT QUITE AS MOIST AS LATE LAST WEEK
WHEN SOME FLASH FLOODING OCCURRED ACROSS THE MID HUDSON VALLEY AND
NW CT. IN ADDITION...STRONG FLOW ALOFT SHOULD KEEP ANY SHOWERS OR
THUNDERSTORMS MOVING RATHER QUICKLY. AS A RESULT...FLASH FLOODING
IS NOT ANTICIPATED WITH THIS STORM SYSTEM. SOME MINOR RISES WILL
BE POSSIBLE ON AREA RIVERS AND STREAMS...ESPECIALLY ACROSS THOSE
AREAS THAT SAW HEAVIER RAIN LAST WEEK. THERE STILL COULD BE
PONDING ON ROADWAYS AND AREAS OF POOR DRAINAGE THROUGH TUESDAY
EVENING.
DRY WEATHER WILL RETURN BY LATE TONIGHT AND CONTINUE THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER AND STREAMS LEVELS TO
RECEDE ONCE MORE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/SND/HWJIV
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
726 AM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BRING SHOWERS AND
EMBEDDED THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL LATER TODAY AND
INTO THIS EVENING. DRY AND SEASONABLE WEATHER RETURNS WEDNESDAY
AND CONTINUES INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
***SHOWERS AND EMBEDDED THUNDERSTORMS MAY BRING LOCALLY HEAVY
RAINFALL/POOR DRAINAGE STREET FLOODING LATER TODAY***
7 AM UPDATE...
FORECAST MOSTLY ON TRACK. WEAK ECHOS ON CURRENT RADAR IMG LIKELY
NOT YET HITTING THE GROUND GIVING DWPT DEPRESSIONS ABOUT 5F OR
HIGHER. TWO AREAS OF PRECIPITATION TO WATCH AND TWO SCHOOLS OF
THOUGHT BETWEEN LATEST MODEL RUNS. THE NORTHERNMOST BAND IS
ASSOCIATED WITH WEAKENING CONVECTION AHEAD OF AN APPROACHING COLD
FRONT WHILE THE SOUTHERN BAND IS MORE CLOSELY ASSOCIATED WITH A
WARM FRONT WHICH IS PROGGED TO REMAIN MOSTLY S OF THE REGION. HAVE
NOTED THAT THESE TWO BANDS WILL FORM TO MAKE A MORE COHESIVE BAND
OF RAIN WITH EMBEDDED TSRA WHICH WILL MOVE THROUGH LATE MORNING
INTO THE AFTERNOON HOURS /LATEST HRRR SHOWS THIS WELL/. HOWEVER
THE TWO OUTCOMES IN MODELS WILL NEED TO BE WATCHED. LATEST NAM
SUGGESTS THAT GIVEN BEST INSTABILITY REMAINS S...HEAVIEST RAIN AND
TSRA REMAIN S AS WELL...CUTTING OFF BEST MOISTURE AND
INSTABILITY...LEADING TO LOWER IMPACT. HOWEVER...RECENT ECMWF RUN
IS FURTHER N AND STRONGER WITH THE WAVE. BOTH ARE CURRENTLY
HANDLING PRECIP LOCATIONS/STRENGTH WELL...SO WILL NEED TO WATCH
HOW INSTABILITY AXIS SHAKES OUT OVER THE NEXT FEW HOURS. THIS MAY
DETERMINE HOW ACTIVE THE AFTERNOON IS.
ALSO...AM NOTING A SECONDARY DEVELOPMENT OF SHOWERS AND STORMS
MORE CLOSELY ASSOCIATED WITH THE FRONT FOR LATE AFTERNOON/EVENING
AFTER THIS INITIAL WEAKENING CONVECTIVE BAND MOVES OUT.
PREVIOUS DISCUSSION FOLLOWS...
CALM WINDS AND DEWPOINTS IN THE 60S HAS ALLOWED AREAS OF DENSE
FOG TO DEVELOP ALONG THE SOUTH COAST/CAPE AND ISLANDS VERY EARLY
THIS MORNING. THIS HAS PROMPTED THE ISSUANCE OF A DENSE FOG
ADVISORY THROUGH 9 AM ACROSS THIS REGION. THE FOG SHOULD BURN OFF
BY MID TO LATE MORNING.
OTHERWISE...SHOWERS AND THUNDERSTORMS HAVE BROKEN OUT EARLY THIS
MORNING ACROSS WESTERN NY/WESTERN PA AHEAD OF A STRONG SHORTWAVE.
THIS ACTIVITY WILL WORK EAST AND OVERSPREAD SOUTHERN NEW ENGLAND
LATER THIS MORNING AND EARLY AFTERNOON. CONFIDENCE IS FAIRLY HIGH
THAT THIS PRECIPITATION WILL BE WIDESPREAD...SO SHOWED AT LEAST LOW
END CATEGORICAL POPS ACROSS MOST AREAS. THERE ARE TWO MAIN CONCERNS
TODAY WHICH WE WILL OUTLINE BELOW:
1) FL0ODING POTENTIAL:
PRETTY GOOD JET DYNAMICS/FORCING ARE ASSOCIATED WITH THIS SHORTWAVE
TROUGH...SO EXPECT LOCALLY HEAVY RAINFALL AND NUISANCE POOR
DRAINAGE STREET FLOODING. WILL INCLUDE THIS WORDING IN OUR FORECAST
AND HAZARDOUS WEATHER OUTLOOK. DECIDED NOT TO ISSUE A FLASH FLOOD
WATCH AT THIS TIME FOR A COUPLE OF REASONS. THE FIRST WAS THAT
PWATS ARE HIGH...BUT GENERALLY UNDER 2 INCHES/SURFACE DEWPOINTS
SHOULD REMAIN BELOW 70 AND BETTER INSTABILITY WILL RESIDE TO OUR
SOUTH. NONETHELESS...GIVEN FAIRLY STRONG FORCING THERE IS STILL A
LOW PROBABILITY FOR VERY LOCALIZED FLASH FLOODING. LATER SHIFTS
WILL HAVE TO KEEP A CLOSE EYE ON THIS POTENTIAL IN CASE A SHORT
FUSED FLASH FLOOD WATCH IS NEEDED.
2) SEVERE WEATHER POTENTIAL:
PRETTY GOOD JET DYNAMIC WILL RESULT IN 0 TO 6 KM SHEAR VALUES ON THE
ORDER OF 35 TO 45 KNOTS TODAY. THE PROBLEM IS THAT WITH A FAIR
AMOUNT OF CLOUD COVER AND POOR MID LEVEL LAPSE RATES...INSTABILITY
WILL REMAIN QUITE LIMITED WITH MLCAPE VALUE GENERALLY UNDER 1000
J/KG. THEREFORE...THINKING THAT THE MAIN THREAT WILL BE HEAVY
RAINFALL AND POOR DRAINAGE STREET FLOODING. HOWEVER...GIVEN THAT
THE 0 TO 6 KM SHEAR WILL BE NEAR OR ABOVE 40 KNOTS WE CAN/T
COMPLETELY LET OUR GUARD DOWN. IF MORE INSTABILITY DEVELOPS THAN
EXPECTED THERE WOULD BE THE THREAT FOR A FEW SEVERE THUNDERSTORMS.
SOMETHING WILL NEED TO KEEP AN EYE ON BUT APPEARS TO BE A LOW
PROBABILITY AT THIS POINT.
&&
.SHORT TERM /WEDNESDAY/...
TONIGHT...
A FEW SHOWERS AND ISOLATED THUNDERSTORMS MAY LINGER DURING THE
EVENING ESPECIALLY ALONG THE COAST. OTHERWISE...MUCH DRIER MID
LEVEL AIR WILL WORK INTO THE REGION BY LATE EVENING BRINGING AN END
TO MOST OF THE PRECIPITATION. MAY SEE SOME PATCHY GROUND FOG
DEVELOP IN THE TYPICALLY PRONE LOCATIONS...ESPECIALLY IN AREAS THAT
SEE A FAIR AMOUNT OF RAIN TODAY. LOW TEMPS WILL MAINLY BE IN THE
UPPER 50S AND LOWER 60S.
WEDNESDAY...
A MIXTURE OF CLOUDS/SUN ALONG WITH GUSTY NORTHWEST WINDS BEHIND THE
COLD FRONT ON WED. LOW RISK OF A BRIEF SPRINKLE/SPOT SHOWER ACROSS
OUR FAR NORTHWEST ZONES...BUT BASICALLY A DRY AND BEAUTIFUL DAY
EXPECTED FOR THE MIDDLE OF AUGUST. HIGH TEMPS WILL MAINLY BE IN THE
70S WITH LOW HUMIDITY. IN FACT...SOME OF THE HIGHEST TERRAIN WILL
STRUGGLE TO REACH 70!
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS...
* QUIET...SEASONABLE WEATHER WED THRU THE WEEKEND
* POSSIBILITY OF SOME RAIN EARLY NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
13/00Z LONG RANGE GUIDANCE CONTINUES TO SHOW QUITE GOOD AGREEMENT
THROUGH MUCH OF THE LONG TERM. INITIAL WEAK CUTOFF IS PROGGED TO
SLIDE INTO THE CANADIAN MARITIMES AS A SECOND CUTOFF DIVES S FROM
HUDSON BAY IN THE PERSISTENT BROAD TROF OVER ERN CANADA AND THE
NORTHEAST CONUS. HOWEVER...THE LONGWAVE TROF AND THIS SECOND
CUTOFF LOOK TO HAVE LITTLE EFFECT ON THE REGION AS STRONG RIDGING
ALONG THE SOUTHERN HALF OF THE CONUS COMBINES WITH RIDGING IN THE
ATLANTIC TO YIELD SUBSIDENCE AND BROAD SFC HIGH PRES OVER THE
NORTHEAST. GIVEN THERE IS GOOD AGREEMENT BETWEEN BOTH OPERATIONAL
MODELS AND THEIR COUNTERPART ENSEMBLES...HAVE REASONABLY HIGH
CONFIDENCE THAT THIS HIGH PRES WILL YIELD A MOSTLY DRY FORECAST
THROUGH EARLY NEXT WEEK. GIVEN THIS...WILL USE A GFS/ECWMF BLEND
AS A BASELINE FOR THIS FORECAST UPDATE.
WED NIGHT INTO FRI...
HIGH PRES GRADUALLY SLIDES IN FROM THE W THROUGH THE PERIOD. WITH
THE HIGH PRES CENTER REMAINING W OF THE REGION...EXPECT US TO
REMAIN ON THE COOLER SIDE OF THE HIGH INITIALLY. H85 TEMPS RANGE
BETWEEN +8C AND ABOUT +11C...SO HIGHS SHOULD START THU AROUND THE
MID 70S...INCREASING TO THE UPPER 70S AND LOW 80S BY FRI AFTER
SOME AIRMASS MODIFICATION. OVERNIGHT MINS WILL BE ON THE COOL SIDE
WITH LOW HUMIDITY /AND THEREFORE LOW DWPTS/ WITH LIGHT FLOW AND
CLEAR SKIES. EXPECTING MINS DIPPING AS LOW AS THE MID 40S IN
NORMALLY COOLER SPOTS. MID 50S IN THE WARMER SPOTS.
THIS COMING WEEKEND...
A WARM FRONT IS EXPECTED TO BEGIN A GRADUAL SLIDE TO THE N
THROUGH THE WEEKEND...BUT WITH HIGH PRES IN PLACE OVER THE REGION
AND VERY SLOWLY SLIDING TO THE E...EXPECTING MOSTLY DRY CONDITIONS
ACROSS SRN NEW ENGLAND DESPITE THIS APPROACHING FRONT. GFS
CURRENTLY SUGGESTS HIGHEST POTENTIAL FOR SOME PRECIP...BUT IT TOO
KEEPS MOST OF ITS GENERATED QPF TO THE W. MID LVL TEMPS DO
INCREASE SOMEWHAT...REACHING +10 TO +13C...SO TEMPS LEAN NEAR TO
SLIGHTLY WARMER THAN NORMAL.
EARLY NEXT WEEK...
DIFFERENCES IN THE TIMING OF A STRONGER SHORTWAVE EFFECTING THE
REGION GIVES WAY TO LOWER CONFIDENCE HERE...BUT IT APPEARS THAT
THERE WILL BE A BIT HIGHER CHANCE FOR SOME PRECIP PARTICULARLY BY
TUE. WILL BE INCREASING TO SOME SLIGHT CHANCE POPS...CLOSER TO THE
ECWMF SOLUTION...WHICH SUGGESTS THE WARM FRONT LIFTS FAR ENOUGH N
TO AFFECT THE REGION WITH THIS SHORTWAVE PASSAGE.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE
ON WEDNESDAY.
TODAY...DENSE FOG BURNS OFF IN NEXT COUPLE OF HOURS. AS A BAND OF
RAIN WITH EMBEDDED THUNDERSTORMS MOVES OVER FROM THE W FROM MID
MORNING INTO THE AFTERNOON...WILL SEE A MIX OF VFR TO IFR...WITH
THE IFR CONDITIONS MOSTLY DUE TO LOW VISIBILITIES IN POCKETS OF
HEAVIER RAIN. EXACT TIMING REMAINS UNCERTAIN.
TONIGHT...LEFT OVER SHOWERS/ISOLATED THUNDERSTORMS
THIS EVENING. OTHERWISE...MAY SEE SOME LINGERING LOW CLOUDS AND FOG
PATCHES PERSIST AT SOME /ESPECIALLY EASTERN/ TERMINALS INTO THE
OVERNIGHT HOURS. AREAL COVERAGE OF LOW CLOUDS AND FOG PATCHES ARE
UNCERTAIN.
WEDNESDAY...ANY LEFT OVER MVFR-IFR CONDITIONS IN SCATTERED LOW
CLOUDS/FOG PATCHES WILL IMPROVE TO VFR NOT LONG AFTER SUNRISE.
OTHERWISE...VFR CONDITIONS.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING. MAY SEE BOUNCING BETWEEN VFR AND LOWER CATEGORIES WITH
RAIN LATE THIS MORNING/AFTERNOON.
KBDL TERMINAL...MODERATE CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY AND TONIGHT...HIGH CONFIDENCE. WINDS AND SEAS WILL REMAIN
BELOW SCA THRESHOLDS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE. THE MAIN CONCERN EARLY THIS MORNING WILL BE FOR DENSE FOG
ACROSS OUR SOUTHERN WATERS. THIS FOG SHOULD BURN OFF TO AT LEAST
SOME DEGREE BY MID TO LATE MORNING. THE OTHER CONCERN WILL BE FOR
EMBEDDED THUNDERSTORMS TO WORK ACROSS THE WATERS...MAINLY THIS
AFTERNOON AND EVENING.
WEDNESDAY...MODERATE CONFIDENCE. NORTHWEST WIND GUSTS OF 25 KNOTS
ARE EXPECTED NEAR SHORE WITH GOOD MIXING BEHIND THE COLD FRONT. ITS
3RD PERIOD SO DID NOT GO WITH ANY HEADLINES AT THIS POINT...BUT
LATER SHIFTS MAY NEED TO CONSIDER A SCA FOR SOME OF OUR NEAR SHORE
WATERS. MAY ALSO SEE SOME 3 TO 5 FOOT SEAS DEVELOP ACROSS OUR
SOUTHERN MOST ATLANTIC WATERS...WHICH MAY ALSO NEED TO BE CONSIDERED
FOR HEADLINES.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. WINDS WILL SHIFT
DIRECTION AS HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND AND THE
WATERS BUT WILL REMAIN BELOW 25 KTS...SAVE FOR POSSIBLY WED
EVENING.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MAZ020>024.
NH...NONE.
RI...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR RIZ006>008.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY
MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
427 AM EDT Tue Aug 13 2013
.NEAR TERM [Today and Tonight]...
As has been quite typical during this very unusual summer, it has
been nearly impossible to keep an established upper level ridge in
place across the SE U.S. So, while on Monday, many areas experienced
an extended period (during the day) of hot and dry conditions with
many high temps in the mid to upper 90s, today is expected to be our
transition back to a wet and trough dominated pattern. Although
the more significant cooler and wetter weather will likely be
reserved for Wednesday and onward for the next several days at
least, PoPs will clearly be on the increase from NW to SE over the
CWA today. Max temps may still reach the lower 90s to the west and
the middle 90s well to the east, but by this afternoon, PoPs are
expected to reach the likely category (60-70% with locally heavy
rainfall likely) across the FL Panhandle, SE AL, and the NW 1/3 of
our GA zones, and PWATs will be back on the increase with many
other favorable factors in place to initiate convection.
Elsewhere, the PoPs are expected to gradually taper off from NW to
SE, with 50s and 40s over the remainder of our GA zones, then
finally down to the 40% to 20% range across the remainder of the
FL Big Bend, so with this much variation, mesoscale updates will
likely be needed to the fcst today, with heavy weighting given to
the Hi-Res Models (including our local and NCEP`s WRF runs, and
the HRRR (High Resolution Rapid Refresh). Tonight`s fcst could be
even more complex in terms of PoPs and timing, so leaned heavily
on a combination of our CAM (Convective Allowing Model) output and
locally generated confidence grids.
&&
.SHORT TERM [Wednesday through Thursday]...
There remains high confidence in widespread rain coverage for the
short term period (Wednesday to Thursday). The ingredients include
a stalling low-level front, a weak upstream trough in the mid-
upper levels of the atmosphere, and a plume of deep moisture. The
NAM, GFS, and ECMWF all show widespread rainfall in this 36-hour
period of around an inch, with locally higher amounts. Therefore,
PoPs were pushed above model guidance again - with widespread
"likely" (60-70%) values during the daytime hours, and high chance
(40-50%) at night. This equates to rain chances roughly 20-30%
above climatology during the entire period. Given very weak flow
(and thus slow storm motions) and high PWATs, the environment
should support locally heavy rainfall. Heavy rain wording was once
again included in the forecast. Given the abundance of rain and
clouds, high temperatures were kept slightly below the model
consensus, and low temperatures slightly above consensus.
&&
.LONG TERM [Thursday Night through Monday]...
A long wave trough will remain in place from the Great Lakes to the
central Gulf Coast early in the period as a reinforcing short wave
in the northern plains drops into the trough, resulting in a closed
low over the Lower Mississippi Valley by Saturday. This low
gradually fills and weakens, leaving behind a weak trough for early
next week with an axis still to our west.
The end result is a prolonged period of rain for the southeast with
periods of heavy rain likely. Total rainfall from the GFS indicates
areas of rain up to 10 inches across the FL panhandle through
Monday, due in part to its development of a tropical cyclone in the
gulf which it brings into the FL panhandle Saturday. The Canadian
also generates a tropical system similar to the GFS, however the
ECMWF does not generate a tropical system and therefore depicts
rainfall totals through Monday of about 5 inches.
Confidence of a period of heavy rain is high, and if the
GFS-advertised tropical system does develop then local rainfall
amounts could be double or triple the current WPC 5.5" totals.
&&
.AVIATION [through 12 UTC Wednesday]...
VFR conditions are expected to prevail for the remainder of the
overnight hours tonight (with the possible exception of MVFR CIGS
at ECP), but the greater concern as we move forward with time will
be the increasing probabilities and coverage of showers and
thunderstorms across the terminals. Initially, the most
pessimistic flying conditions will be at the northern and western
terminals (DHN, ECP, and ABY), but MVFR/IFR restrictions will
likely spread eastward towards TLH and VLD along with the
convection later this afternoon and evening. However, when all is
said and done, the most challenging portion of the fcst will
likely be between 06 and 12 UTC on Wed., where if there is a
significant break in the convection and residual mid and upper
level clouds, very low CIGS and or vis could develop and become
problematic.
&&
.MARINE...
A gradual increase in the pressure gradient over the next few days
should cause winds to increase from the 5-10 knot range more into
the 10-15 knot range, with perhaps a slight increase in seas. We
will be keeping an eye on the western Caribbean and southern Gulf
of Mexico for tropical development in the next five days. The NHC
has posted a "low chance" of development for those areas, and
therefore we mentioned this possibility in the CWF text.
&&
.FIRE WEATHER...
ed flag conditions are not expected over the next several days, as
wet and more humid weather will make a quick return to the region.
&&
.HYDROLOGY...
Widespread rainfall totals of at least 3 inches appear likely over
the next week, which will likely cause an increase in flows on
area rivers - particularly after Thursday. The vast majority of
rivers and creeks in the area are below bankfull levels thanks to
a relatively dry period in the past week or so. Therefore, it will
likely take a few days worth of heavy rainfall to cause more
widespread increases in the flows on area rivers. It is too early
to determine flooding potential on specific rivers, as that will
ultimately hinge on the location and intensity of the heaviest
rainfall.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 93 75 91 75 89 / 40 30 60 50 70
Panama City 90 78 88 77 86 / 50 60 60 50 70
Dothan 92 74 87 74 87 / 70 30 70 50 70
Albany 93 75 88 74 88 / 60 30 70 50 70
Valdosta 95 74 91 74 90 / 40 30 60 50 70
Cross City 94 75 93 74 90 / 20 30 40 30 40
Apalachicola 89 79 88 78 86 / 30 50 50 40 60
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Lamers
LONG TERM...Hollingsworth
AVIATION...Gould
MARINE...Lamers
FIRE WEATHER...Gould
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
325 PM EDT TUE AUG 13 2013
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
SHORT RANGE MODELS CONTINUE TO SHOW A COLD FRONT...CURRENTLY ACROSS
TN... SAGGING ACROSS NORTH GA TONIGHT AND STALLING ACROSS CENTRAL GA
WEDNESDAY AFTERNOON. REGIONAL RADARS SHOW SCATTERED SHOWERS AND
THUNDERSTORMS BEGINNING TO DEVELOP ACROSS THE FORECAST AREA AS AN
UPPER DISTURBANCE APPROACHES FROM THE WEST. EXPECT A WEAK SURFACE
TROUGH TO HELP PROVIDE A FOCUS ACROSS NORTH GA THIS AFTERNOON AND
RADAR TRENDS SUPPORT THAT...WITH A SCATTERED LINE OF CONVECTION
DEVELOPING FROM WEST OF ROME...EASTWARD TO JASPER AND CLEVELAND.
EXPECT THIS ACTIVITY TO SAG SOUTHWARD THROUGH THE LATE AFTERNOON AND
EVENING HOURS. ADDITIONAL SCATTERED TO NUMEROUS CONVECTION IS
DEVELOPING ACROSS PARTS OF CENTRAL GA WHERE THE GREATER
INSTABILITIES AND DEEPER MOISTURE ARE POOLED. THE HRRR MODEL
CLUSTERS MOST OF THE CONVECTIVE ACTIVITY ACROSS THE CENTRAL ZONES...
FROM AREAS AROUND COLUMBUS TO MACON TO MILLEDGEVILLE AND SOUTHWARD
DURING THE LATE AFTERNOON AND EVENING HOURS. THUNDERSTORM ACTIVITY
MAY PERSIST THROUGH MID EVENING BEFORE DIMINISHING TO MAINLY
SHOWERS. SCATTERED SHOWERS MAY PERSIST OVERNIGHT ALONG AND AHEAD OF
THE COLD FRONT... BUT ANY THUNDERSTORM ACTIVITY SHOULD BE VERY
ISOLATED AT BEST OVERNIGHT. THE MAIN THUNDERSTORM THREAT THROUGH THE
EVENING WILL CONTINUE TO BE LOCALLY HEAVY RAIN AND POSSIBLE BRIEF
FLOODING. HOWEVER... WITH 2500-3000 CAPE... CANNOT RULE OUT A PULSE
STRONG STORM PRODUCING WIND GUSTS TO 40-45 MPH AND POSSIBLY SOME
SMALL HAIL. MODELS AGREE ON DRIER AIR SPREADING IN BEHIND THE FRONT
ACROSS NORTH GA BY EARLY WEDNESDAY... SO WILL SHOW THE GREATER RAIN
CHANCES ACROSS CENTRAL GA ON WEDNESDAY...AND MAINLY ALONG AND SOUTH
OF A LA GRANGE TO WARRENTON LINE...WITH ONLY A LOW CHANCE IN THE
ATLANTA METRO AREA FOR WEDNESDAY AFTERNOON. LOCALLY HEAVY RAIN WILL
REMAIN A THREAT ACROSS CENTRAL GA WEDNESDAY AFTERNOON AS THE FRONT
PROVIDES A FOCUS FOR TRAINING CONVECTION. MODELS SHOW GENERALLY ONE
QUARTER TO ONE HALF INCH FROM COLUMBUS TO MACON AND SOUTHWARD ON
WEDNESDAY... BUT ISOLATED HIGHER AMOUNTS OF 1 TO 3 INCHES ARE
POSSIBLE. ALTHOUGH CANNOT RULE OUT A PULSE STRONG TO SEVERE STORM
ALONG OR SOUTH OF THE FRONT WEDNESDAY AFTERNOON... NOT EXPECTING
ANYTHING WIDESPREAD AND THE GREATER STRONG STORM THREAT SHOULD BE
JUST SOUTH OF THE FORECAST AREA WEDNESDAY AFTERNOON AND EVENING.
OTHERWISE... AS FOR TEMPS A MODEL BLEND THROUGH THE SHORT TERM
LOOKED REASONABLE.
39
.LONG TERM /THURSDAY THROUGH TUESDAY/...
GUIDANCE CONTINUES TO POINT TO A WET EXTENDED PERIOD. AS THE FRONT
SAGS SOUTH OF THE AREA TROUGH THE SHORT TERM...SURFACE HIGH UNDER
CONFLUENT FLOW ALOFT WILL SLIP EAST AND ACROSS THE APPALACHIANS IN
A HYBRID DAMMING EVENT. THE QUESTION WILL BE HOW MUCH GULF
MOISTURE WILL INTERACT WITH THE DAMMING. FOR THURSDAY...WITH THE
STALLED FRONT AND ONSET OF HYBRID CAD...HPC AND SYNOPTIC MODELS
KEEP THE BEST PRECIP ACROSS CENTRAL GEORGIA...WITH A GOOD INCH OF
BASIN-AVERAGE QPF DURING THE DAY. THIS TREND CONTINUES INTO
FRIDAY. BESIDES THE PRECIP HOWEVER...THE BIGGEST SENSIBLE IMPACT
WILL BE TEMPS. CURRENT HIGH TEMPS FOR THURSDAY THROUGH SATURDAY DO
NOT BRING NORTH GEORGIA OUT OF THE 70S...AND REALLY ONLY INTO THE
MID 80S IN SOUTHERN ZONES. POSSIBLY A SLIGHT WARMING TREND BY A
DEGREE OR SO ON SUNDAY BUT THIS REMAINS TO BE SEEN. THESE FORECAST
MAX TEMPS ARE A GOOD 10 DEGREES COOLER THAN SEASONAL NORMALS...
THE KIND OF IMPACTS NORMALLY SEEN WITH CLASSICAL CAD RATHER THAN
HYBRID CAD.
00Z ECMWF CONTINUES TO TAKE THE TROPICAL WAVE /CURRENTLY IN THE
CARIBBEAN/ FURTHER WEST TOWARD THE YUCATAN...WHILE GFS AND
CANADIAN BRING IT INTO THE GULF AND CLOSE TO THE COAST FRIDAY
NIGHT. FOR WHAT ITS WORTH...THE CANADIAN IS STRONGER AND FURTHER
WEST WITH THE SURFACE LOW THAN THE GFS...WHICH WOULD POSSIBLY
INDICATE SEVERE POTENTIAL ON SATURDAY...BUT IT IS A BIT OF AN
OUTLIER THERE. ECMWF IS DRIEST WHILE GFS/CMC ARE WETTER
SOLUTIONS. HPC NOT GOING NEARLY AS HIGH AS THE GFS BUT EVEN
SO...WITH THE PROLONGED WET PERIOD ACROSS ESPECIALLY CENTRAL
GEORGIA FROM THE SHORT TERM FRONT...THERE IS SOME CONCERN ABOUT
THE RAINFALL PILING UP. HAVE NOT DONE A COMPLETE DIAGNOSIS TO
DETERMINE IF THE THURSDAY-FRIDAY RAIN WOULD QUALIFY AS A PRE
/PREDECESSOR RAINFALL EVENT/ BUT IN ANY CASE THE 7-DAY QPF TOTAL
FROM HPC ARE UPWARDS OF 6 INCHES ACROSS PORTIONS OF CENTRAL
GEORGIA. THIS BEING BASIN-AVERAGE...IMPLYING THAT SOME AREAS
COULD GET SUBSTANTIALLY MORE /AND OF COURSE SOME AREAS
SUBSTANTIALLY LESS/. ALL INTERESTS SHOULD STAY TUNED TO LATEST
FORECASTS AS THIS IS REFINED OVER THE NEXT FEW DAYS.
SO OVERALL...REALLY MADE ONLY MINOR CHANGES TO PREVIOUS EXTENDED
FORECAST. REFINED AND ADDED SOME DETAIL TO DAYS 4 AND 5 ESPECIALLY
WITH TEMPS WINDS AND DEWPOINTS /VERY LITTLE IF ANY CHANGE TO
POPS/ AND MADE SOME MINOR ADJUSTMENTS TO HIGH TEMPS THROUGH THE
REST OF THE PERIOD TO REFLECT THE PROLONGED COOL SPELL.
TDP
&&
.AVIATION...
18Z UPDATE...
VFR CIGS WILL PERSIST THROUGH THE TAF PERIOD. WRF AND HRRR MODELS
SHOW SCT CONVECTION BRUSHING ATL AROUND 21-23Z TODAY... SO WILL SHOW
TEMPO -TSRA AT THIS TIME. A COLD FRONT PUSHES INTO NORTH GA TONIGHT
AND SPREADS SOME DRIER AIR SOUTHWARD BY WED MORN. THIS SHOULD HINDER
ANY THREAT OF LOW CIGS AT ATL BY EARLY WED MORN. EXPECT A WNW WIND
AROUND 10G15KTS THIS AFTERNOON TO BECOME MORE NW AND DIMINISH TO
AROUND 6-8KTS BY 03Z... THEN NNW WINDS AROUND 8-10KTS BY 15Z WED.
THE FRONT MOVES SOUTH OF ATL EARLY WED WITH A DRIER NW FLOW...SO NO
MENTION OF TSRA FOR ATLANTA AREA ON WED.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TEMPO -TSRA THIS AFTERNOON. HIGH ON ALL OTHER
ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 69 88 68 78 / 50 40 20 30
ATLANTA 70 86 69 79 / 50 30 20 50
BLAIRSVILLE 64 81 64 76 / 50 20 20 30
CARTERSVILLE 68 86 64 82 / 50 20 20 30
COLUMBUS 73 87 71 84 / 40 60 40 80
GAINESVILLE 69 85 68 76 / 50 20 20 30
MACON 72 89 71 82 / 40 60 50 80
ROME 68 89 63 83 / 50 20 10 30
PEACHTREE CITY 70 86 66 79 / 40 40 20 50
VIDALIA 74 88 71 84 / 30 60 60 80
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....TDP
AVIATION...39
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
150 PM EDT TUE AUG 13 2013
.MORNING UPDATE...
/ISSUED AT 1107 AM EDT TUE AUG 13 2013/
LATEST SURFACE ANALYSIS SHOWS A WEAK TROUGH ACROSS NORTH GA WITH A
COLD FRONT ACROSS WEST TN AND INTO THE OHIO VALLEY. THE UPPER LEVELS
SHOW WEAK DISTURBANCES APPROACHING FROM THE WEST. CONVECTIVE MODELS
INDICATE POSSIBLY TWO ROUNDS OF CONVECTION THIS AFTERNOON AND
EVENING...THE FIRST POSSIBLY FOCUSED ALONG THE SURFACE TROUGH TO THE
NORTH AND THIS ACTIVITY SAGS SOUTH INTO CENTRAL GA DURING THE MID TO
LATE AFTERNOON HOURS. ANOTHER ROUND PUSHES INTO NORTH GA AHEAD OF
THE COLD FRONT LATE THIS AFTERNOON-EARLY EVENING AND ALSO SAGS SOUTH
OVERNIGHT... ALTHO THIS ACTIVITY WILL WEAKEN TO MAINLY JUST SHOWERS
BY LATE EVENING. HAVE UPDATED ZONES TO TWEAK LIKELY POPS MORE INTO
WEST CENTRAL ZONES THIS AFTERNOON AND HELD ONTO SLIGHTLY HIGHER POPS
NORTH THROUGH THE EVENING HOURS. MORNING SOUNDING SUGGEST LOCALLY
HEAVY RAIN WILL CONTINUE TO BE THE MAIN THREAT WITH SOUNDING SHOWING
NEAR 2 INCH PW`S. FREQUENT LIGHTNING...WIND GUSTS TO 40 MPH... AND
SMALL HAIL WILL ALSO BE POSSIBLE THROUGH MID EVENING WITH THE
STRONGER STORMS. /39
.PREVIOUS DISCUSSIONS /ISSUED AT 440 AM EDT TUE AUG 13 2013/...
SHORT TERM /TODAY THROUGH WEDNESDAY/...
VARIOUS LEVELS OF CLOUDS OVER GA THIS MORNING DUE TO PREVIOUS TSTMS
MONDAY EVENING. LOW STRATUS IS DEVELOPING OVER WET GROUND AT THIS
TIME FROM RAINFALL IN THE PAST 24 HOURS. A COLD FRONT WAS MOVING
SOUTHEAST THROUGH KY AND AR WHILE A NEAR ZONAL FLOW PREVAILED OVER
GA. EXPECT ENOUGH DIURNAL HEATING AND SYNOPTIC SCALE FORCING IN
ADVANCE OF THE COLD FRONT TODAY TO LIFT THE LOW STRATUS AND THEN
DOMINATE WITH A BKN CU FIELD. WITH SO MUCH TROPICAL MOISTURE
AVAILABLE...PWS NEAR 2 INCHES...EXPECT SCATTERED TSTMS TO DEVELOP AS
EARLY AS 1000 AM EDT OVER NORTH GA IN ADVANCE OF THE APPROACHING
COLD FRONT THROUGH THE TN VALLEY. THE REMAINDER OF NORTH GA
INCLUDING THE ATL AREA WILL BE AROUND NOON OR LATER. THE FRONT
SHOULD ENTER NORTHWEST GA AROUND 800 PM EDT AND CONTINUE MOVING INTO
CENTRAL GA BY WEDNESDAY MORNING. THE SCATTERED TO NUMEROUS TSTMS
THIS AFTERNOON SHOULD DIMINISH TO ISOLATED OVERNIGHT AS THE AIRMASS
OVER GA GRADUALLY STABILIZES FROM PRECIPITATION AND EVAPORATIONAL
COOLING. THE NEARLY STATIONARY FRONT OVER CENTRAL AND SOUTH GA
COMBINED WITH AN APPROACHING UPPER LEVEL DISTURBANCE WILL INITIATE
NUMEROUS TSTMS OVER CENTRAL GA BY WEDNESDAY AFTERNOON AND EVENING.
ISOLATED TO SCATTERED TSTMS CAN BE EXPECTED OVER NORTH GA. FAVORED
AND INCREASED THE WETTER NAM SOLUTION DURING THE FORECAST PERIOD.
TEMPS WERE A MET/MAV MOS GUIDANCE BLEND.
16
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
GFS AND EUROPEAN MODELS INDICATING AN INCREASINGLY WET PERIOD.
A STATIONARY FRONT WILL LIE ACROSS THE CENTRAL TO S GA AREA TO START
THE LONG TERM WITH AN UPPER LEVEL TROUGH EXPECTED TO DEVELOP IN THE
THURSDAY TO FRIDAY TIME FRAME OVER THE MID U.S AND DRIFT E. THIS
WILL ALLOW FOR MOIST SOUTHERLY FLOW TO DEVELOP ALONG WITH A CAD TYPE
AIRMASS OVER THE NORTH. 50-80 PERCENT POPS CAN BE EXPECTED FOR MUCH
OF THE AREA WEDNESDAY NIGHT THROUGH MONDAY AND HAVE LEANED HARD ON
HPC GUIDANCE WITH HIGHER POPS AND LOWER DAYTIME TEMPERATURES. THE
UPPER TROUGH WILL WEAKEN ON MONDAY WITH THE GFS AND EUROPEAN
DIFFERING ON HOW MUCH IT WEAKENS INTO TUESDAY.
SIGNIFICANT RAINFALL CAN BE EXPECTED DURING THIS PERIOD FAVORING
CENTRAL GA MORE THAN N GA. THE GFS IS INDICATING A HEAVY PRECIP
BULLSEYE AND IS MOST LIKELY OVERDONE COMPARED TO THE MORE REASONABLE
LOOKING EUROPEAN.
HIGH TEMPERATURES WILL BE ON THE ORDER OF 5-10 DEGREES BELOW NORMAL.
LOW TEMPERATURES WILL BE CLOSE TO SLIGHTLY BELOW NORMAL FOR MUCH OF
THE PERIOD.
BDL
&&
.AVIATION...
18Z UPDATE...
VFR CIGS WILL PERSIST THROUGH THE TAF PERIOD. WRF AND HRRR MODELS
SHOW SCT CONVECTION BRUSHING ATL AROUND 21-23Z TODAY... SO WILL SHOW
TEMPO -TSRA AT THIS TIME. A COLD FRONT PUSHES INTO NORTH GA TONIGHT
AND SPREADS SOME DRIER AIR SOUTHWARD BY WED MORN. THIS SHOULD HINDER
ANY THREAT OF LOW CIGS AT ATL BY EARLY WED MORN. EXPECT A WNW WIND
AROUND 10G15KTS THIS AFTERNOON TO BECOME MORE NW AND DIMINISH TO
AROUND 6-8KTS BY 03Z... THEN NNW WINDS AROUND 8-10KTS BY 15Z WED.
THE FRONT MOVES SOUTH OF ATL EARLY WED WITH A DRIER NW FLOW...SO NO
MENTION OF TSRA FOR ATLANTA AREA ON WED.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TEMPO -TSRA THIS AFTERNOON. HIGH ON ALL OTHER
ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 69 87 69 / 50 40 50 50
ATLANTA 87 70 85 70 / 60 40 50 40
BLAIRSVILLE 82 65 82 64 / 70 30 20 40
CARTERSVILLE 87 68 88 66 / 90 50 20 30
COLUMBUS 91 73 88 71 / 70 50 60 50
GAINESVILLE 87 70 85 69 / 60 50 40 40
MACON 91 72 88 71 / 60 30 60 50
ROME 88 68 88 65 / 90 40 20 20
PEACHTREE CITY 87 69 86 70 / 60 40 60 40
VIDALIA 93 74 90 72 / 50 30 60 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...16/39
LONG TERM....BDL/25
AVIATION...39
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1228 PM CDT TUE AUG 13 2013
.DISCUSSION...
1050 AM CDT
FOR MORNING UPDATE...
NO SIGNIFICANT CHANGES TO NEAR TERM FORECAST THIS MORNING. ONLY
MINOR TWEAKS TO HOURLY TEMP/SKY COVER GRIDS BASED ON CURRENT OBS AND
SATELLITE TRENDS.
SPRAWLING CANADIAN SURFACE HIGH PRESSURE CONTINUES TO BUILD
SOUTHEAST FROM THE LAKE WINNIPEG AREA OF SOUTHERN MANITOBA LATE THIS
MORNING...WITH BREEZY NORTH-NORTHEAST SURFACE WINDS AHEAD OF THE
ADVANCING ANTICYCLONE BRINGING COOLER AND DRIER ALMOST EARLY-AUTUMN
LIKE AIR TO THE FORECAST AREA. IN FACT...THE COOL AIR ALOFT...WITH
+5C SAMPLED AT 850 MB IN THE GREEN BAY WISC 12Z RAOB...HAS LED TO
DEVELOPMENT OF LAKE EFFECT STRATOCU ACROSS LAKE MICHIGAN. THIS LAKE
INDUCED CLOUD COVER WAS SPREADING INLAND INTO THE CHICAGO METRO AREA
DOWNWIND OF THE LAKE. ASSESSMENT OF THE MORNING RAOB DATA AND MODEL
LOW-LEVEL THERMAL FIELDS CONTINUES TO INDICATE A RATHER COOL DAY FOR
MID-AUGUST...WITH HIGHS RANGING FROM PERHAPS THE UPPER 60S ALONG THE
LAKE MICHIGAN SHORE...TO THE LOW-MID 70S IN THE WARMEST INLAND
REACHES SUCH AS DIXON/PONTIAC. DEW POINT TEMPS IN THE MID-UPPER 40S
WILL MAKE FOR DRY CONDITIONS THIS AFTERNOON AS WELL...AS WINDS BEGIN
TO DIMINISH WITH THE GRADIENT GRADUALLY WEAKENING WITH THE APPROACH
OF THE HIGH PRESSURE CENTER.
RATZER
//PREV DISCUSSION...
327 AM CDT
WITH EXPANSIVE SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTHWEST
AND THEN ESTABLISHING ITSELF OVER THE GREAT LAKES REGION THROUGH THE
WEEKEND...THERE ARE NO REAL WEATHER CONCERNS FOR THE AREA.
HOWEVER...AN UNSEASONABLY COOL AIR MASS IS PLUNGING SOUTH DOWN LAKE
MICHIGAN BEHIND A SECONDARY COLD FRONT AND SHARP TROUGH AXIS SEEN
WELL ON WATER VAPOR IMAGERY EARLY THIS MORNING. THIS WILL QUICKLY
TRANSPORT THE MID SINGLE DIGIT 850 MB TEMPS OVER ONTARIO ON THE 00Z
RAOB TO OUR AREA BY THIS AFTERNOON...WHICH WILL MAKE FOR MORE
FALL-LIKE THAN SUMMER-LIKE HIGH TEMPERATURES PRIMARILY IN THE LOWER
70S...WITH A SCATTERING OF MID 70S READINGS IN THE FAR SOUTH AND
WEST. DESPITE A VERY DRY AIRMASS...STEEPENING LOW LEVEL LAPSE RATES
AND NEAR SATURATION AT ABOUT 800 MB WILL LIKELY RESULT IN A
BLOSSOMING STRATOCU DECK BY MID TO LATE MORNING THAT WILL GRADUALLY
DISSIPATE THROUGH THE EVENING.
IN ADDITION...FORECAST SOUNDINGS INDICATE FAVORABLE PROFILES FOR
GENERATION OF LAKE EFFECT CLOUDS WHICH ARE EXPECTED TO BE CARRIED ON
STRONG NORTHERLY FLOW INTO NEAR LAKE AREAS OF NORTHWEST
INDIANA...WHICH WILL LIMIT HIGHS THERE TO THE UPPER 60S. NORTHEAST
ILLINOIS MAY SEE A BIT OF A SHADOWING EFFECT TO KEEP CLOUD COVER AT
A MINIMUM FOR A TIME...BUT THE LAKESHORE WILL STILL STRUGGLE TO
REACH 70 DEGREES. ADDING TO THE FALL-LIKE FEEL WILL BE GUSTY
NORTH-NORTHEAST WINDS...STRONGEST NEAR THE LAKEFRONT...THANKS TO
A TIGHT PRESSURE GRADIENT AND THE UNSTABLE CONDITIONS OVER THE
LAKE. THOSE THAT BRAVE THE COOL CONDITIONS TO HEAD TO THE BEACH
WILL BE GREETED BY HIGH WAVES AND DANGEROUS CURRENTS...SO SWIMMING
IS STRONGLY DISCOURAGED.
TONIGHT...WINDS WILL QUICKLY DIMINISH AS THE HIGH BUILDS IN AND
SKIES SHOULD CLEAR FOR MOST AREAS AFTER ANY LINGERING EVENING
STRATOCU. THIS WILL SET THE STAGE FOR VERY CHILLY CONDITIONS IN
RURAL AND OUTLYING SUBURBAN AREAS WHERE UPPER 40S ARE EXPECTED AND
EVEN A FEW MID 40S ARE POSSIBLE. THE CHICAGO HEAT ISLAND WILL DROP
TO NEAR 60 DEGREES. THE EXCEPTION TO THE ABOVE WILL BE THE
NORTHWEST INDIANA AND POSSIBLY FAR EAST AND SOUTHEAST COOK COUNTY
LAKEFRONT...WHERE FAVORABLE LAKE EFFECT CONDITIONS WILL CONTINUE
TO EXIST AND RESULTANT CLOUD COVER WILL KEEP TEMPERATURES MILDER.
CONSIDERED PUTTING IN A SLIGHT CHANCE POP FOR LAKE EFFECT SHRA BUT
HELD OFF AND WILL ALLOW THE DAY SHIFT TO ASSESS...AS THE AIR MASS
MOVING OVER THE LAKE IS VERY DRY.
ON WEDNESDAY AND BEYOND...INVERSION LEVELS WILL DROP AS MID LEVEL
HEIGHTS RISE...SO ANY LAKE EFFECT CLOUDS WILL LIKELY DIMINISH
EARLY...BUT EXPECT TO SEE BLOSSOMING CUMULUS AGAIN BY LATE MORNING.
850 MB TEMPERATURES WILL BE CLOSE TO TODAY...BUT 925 MB TEMPS WILL
RISE TO SUPPORT A FEW DEGREE RISE IN HIGH TEMPERATURES. THE
CONTINUED GRADUAL DEPARTURE OF THE DEEP TROUGH OVER EASTERN CANADA
AND THE GREAT LAKES WILL RESULT IN WARMING THERMAL PROFILES ON
THURSDAY...SO AFTER ANOTHER CLEAR AND CHILLY NIGHT...SOME LOCATIONS
MAY TAG 80 DEGREES. THE SLOW WARMING TREND WILL THEN CONTINUE
THROUGH THE WEEKEND INTO EARLY NEXT WEEK...WITH HIGHS IN THE MID 80S
OR EVEN WARMER POSSIBLY BY MONDAY. THE SOUTHEASTERN CWA COULD SEE
ENOUGH MOISTURE RETURN BEHIND HIGH PRESSURE FINALLY SHIFTING TO THE
EAST FOR A LIMITED THREAT FOR TSRA BY MONDAY OR POTENTIALLY AS EARLY
AS SUNDAY...BUT OTHERWISE THE DRY PATTERN MOST OF THE AREA HAS BEEN
IN SINCE THE BEGINNING OF JULY WILL CONTINUE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/GUSTY NORTH/NORTHEAST WINDS THROUGH EARLY THIS EVENING.
CMS
//DISCUSSION...UPDATED 18Z...
ONLY FORECAST CONCERN THIS PERIOD ARE WINDS. HIGH PRESSURE ACROSS
THE NORTHERN PLAINS WILL SPREAD SOUTHEAST ACROSS THE AREA
OVERNIGHT INTO WEDNESDAY. GUSTY NORTHEASTERLY WINDS WILL CONTINUE
THIS AFTERNOON BUT BEGIN TO SLOWLY DIMINISH. POSSIBLE GUSTS WILL
DIMINISH PRIOR TO CURRENT END TIME...POSSIBLY AS EARLY AS 22Z-
23Z...ESPECIALLY ACROSS NORTHWEST IL. AS THE HIGH APPROACHES THIS
EVENING...WINDS MAY TURN NORTHWESTERLY OR EVEN WESTERLY...BUT AT
THAT TIME SPEEDS WILL BE WELL UNDER 10 KTS. WINDS WILL THEN BECOME
LIGHT AND VARIABLE OR CALM OVERNIGHT. LIGHT NORTH/NORTHEAST WINDS
EXPECTED WEDNESDAY MORNING WITH A LAKE BREEZE TURNING WINDS MORE
EASTERLY WEDNESDAY AFTERNOON. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR WINDS THIS AFTERNOON...MEDIUM FOR THE REST OF THE
PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH MONDAY...VFR.
MDB
&&
.MARINE...
300 AM CDT
A SERIES OF COLD FRONTS HAS NOW PUSHED SOUTH OF LAKE MICHIGAN WITH A
FAIRLY TIGHT PRESSURE GRADIENT POSITIONED ACROSS THE LAKE WITH LOW
PRESSURE TO THE EAST OVER EASTERN ONTARIO AND A STRONG HIGH PRESSURE
SYSTEM TO THE WEST FROM MANITOBA ACROSS THE DAKOTAS. NORTH TO
NORTHEAST WINDS HAVE INCREASED ACROSS THE LAKE AND WILL REMAIN
STRONG THROUGH LATE AFTERNOON AT WHICH POINT SPEEDS WILL BEGIN TO
GRADUALLY EASE AS THE PRESSURE GRADIENT SLACKENS. WESTERN AND
NORTHERN SECTIONS OF THE LAKE WILL SEE WINDS DIMINISHING FIRST AS
THE GRADIENT WILL BE WEAKENING FROM NORTHWEST TO SOUTHEAST. WAVES
WILL CONTINUE TO BUILD THIS MORNING WITH THE LONG FETCH DIRECTING
THEM AT THE SOUTHERN SHORELINES. HAVE BUMPED WAVES UP TO 5 TO 8 FT
WITH OCCASIONAL 12 FT FOR THE SOUTHERN PARTS OF THE LAKE WITH WELL
EXPOSED BUOYS NEAR THE END OF THE DEVELOPING FETCH ALREADY SHOWING
WAVES IN THE 4 TO 6 FT RANGE...WITH A FEW PEAKS CLOSER TO 7 FT. WILL
CONTINUE WITH THE SMALL CRAFT ADVISORY AS-IS. THE HIGH WILL MOVE
SOUTHWARD AND SETTLE INTO ILLINOIS INTO WEDNESDAY AND THEN GRADUALLY
SPREAD EASTWARD ACROSS THE OHIO VALLEY THROUGH THE END OF THE WEEK.
NORTHERLY WINDS WILL LIKELY TURN ONSHORE WEDNESDAY WITH THE WEAK
PRESSURE GRADIENT IN PLACE BEFORE SHIFTING TO SOUTHERLY ACROSS MOST
OF THE LAKE WEDNESDAY NIGHT AS THE HIGH SHIFTS. SOUTHWEST TO WEST
WINDS ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK BUT ONSHORE
FLOW WILL LIKELY SET UP ACROSS SOUTHERN PARTS OF THE LAKE WHERE THE
PRESSURE GRADIENT WILL REMAIN WEAK INTO THE WEEKEND.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 AM WEDNESDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1148 AM CDT Tue Aug 13 2013
.DISCUSSION...
ISSUED 950 AM CDT Tue Aug 13 2013
Large shield of cirrus clouds continues to push eastward this
morning, but has been showing some thinning as of late. Have had
quite a bit of stratus over the southeast CWA which is a bit
stubborn to erode, and a narrow band has also been quickly
dropping southwest toward the I-74 corridor as cooler and drier
air works its way toward our area. The diurnal cumulus should
start forming over the next couple hours, but latest CU-rule off
the RAP model diminishes this from north to south as the drier air
aloft mixes downward, so sunshine should be on the increase during
the afternoon.
Have made the usual minor hourly temperature adjustments for
today, which generally did not impact the high temperature
forecasts. Also refreshed the zone forecasts to remove mention of
morning fog in the eastern CWA, although little change was needed
otherwise.
Geelhart
&&
.AVIATION...
ISSUED 1147 AM CDT Tue Aug 13 2013
Narrow band of MVFR ceilings continues to drop southwest as drier
air moves into central Illinois. Will see these continue for
another hour or two from KSPI-KDEC-KCMI, with diurnal cumulus
above 3000 feet forming afterward. Greatest question with ceilings
will be at KCMI, where lake-effect clouds continue to stream
southward toward the area. Clouds will fade mid to late afternoon
in most areas. Mainly clear skies expected tonight into Wednesday
morning, as high pressure settles into the mid-Mississippi Valley.
Northeast winds will gradually trend more northerly Wednesday
morning with the arrival of the high.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 253 AM CDT Tue Aug 13 2013
SHORT TERM...Today through Thursday
07z/2am surface analysis shows cold front settling southward
toward the Ohio River, with bulk of remaining convection now well
to the south across far southern Indiana into Kentucky. Despite
frontal passage and light northerly flow, air mass remains rather
humid across central Illinois. Surface dew points are still in the
middle to upper 60s across most of the area, with drier upper 50s
beginning to filter into the far north around Galesburg. Due to
mostly clear skies and light winds, this lingering low- level
moisture is producing some patchy fog around the area. Will
include fog mention in the forecast this morning, mainly for
locations south of I-72 where moisture will linger longest. After
any early morning fog dissipates, mostly sunny and cool weather
will be the rule today. Secondary cold front will allow very cool
air mass to pour southward into Illinois today, with 850mb temps
expected to drop into the 8 to 10C range. Numeric guidance is
suggesting highs only in the lower to middle 70s: however, based
on upstream readings yesterday afternoon and strength of mid-
August sun, think this is too cool. Will go several degrees above
guidance, with highs ranging from the middle 70s far north, to the
lower 80s along and south of I-70.
Clear skies and light winds will allow excellent radiational
cooling conditions to develop tonight, resulting in chilly
overnight lows in the upper 40s and lower 50s. With high pressure
remaining overhead, the cool/dry weather will continue on
Wednesday and Thursday as well, with highs in the middle to upper
70s and lows mainly in the 50s.
LONG TERM...Friday through Monday
Short-wave currently evident on water vapor imagery over Oregon
will track up and over the western CONUS ridge and into the
Midwest by the end of the week. This feature may trigger scattered
showers/thunder across Iowa and Nebraska Thursday night; however,
by the time it arrives in the drier air mass across Illinois, am
expecting only a slight increase in cloud cover on Friday. The
wave will act to amplify the existing long-wave trough in place
across the eastern CONUS this weekend into early next week. 00z
Aug 13 models continue to suggest the amplifying trough will
eventually lead to the development of an inverted surface trough
across the Ohio River Valley Sunday/Monday. This is the second
straight day models have latched onto this solution, so confidence
is growing that disturbed weather may develop to the E/SE early
next week. GFS/ECMWF spread a few showers into east-
central/southeast Illinois Sunday and Monday, however GEM tends to
keep precip a bit further east across Indiana. Will increase cloud
cover and carry a slight chance POP east of I-57 accordingly. Air
mass will slowly moderate through the period, with high
temperatures climbing back into the lower to middle 80s by Sunday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1050 AM CDT TUE AUG 13 2013
.DISCUSSION...
1050 AM CDT
FOR MORNING UPDATE...
NO SIGNIFICANT CHANGES TO NEAR TERM FORECAST THIS MORNING. ONLY
MINOR TWEAKS TO HOURLY TEMP/SKY COVER GRIDS BASED ON CURRENT OBS AND
SATELLITE TRENDS.
SPRAWLING CANADIAN SURFACE HIGH PRESSURE CONTINUES TO BUILD
SOUTHEAST FROM THE LAKE WINNIPEG AREA OF SOUTHERN MANITOBA LATE THIS
MORNING...WITH BREEZY NORTH-NORTHEAST SURFACE WINDS AHEAD OF THE
ADVANCING ANTICYCLONE BRINGING COOLER AND DRIER ALMOST EARLY-AUTUMN
LIKE AIR TO THE FORECAST AREA. IN FACT...THE COOL AIR ALOFT...WITH
+5C SAMPLED AT 850 MB IN THE GREEN BAY WISC 12Z RAOB...HAS LED TO
DEVELOPMENT OF LAKE EFFECT STRATOCU ACROSS LAKE MICHIGAN. THIS LAKE
INDUCED CLOUD COVER WAS SPREADING INLAND INTO THE CHICAGO METRO AREA
DOWNWIND OF THE LAKE. ASSESSMENT OF THE MORNING RAOB DATA AND MODEL
LOW-LEVEL THERMAL FIELDS CONTINUES TO INDICATE A RATHER COOL DAY FOR
MID-AUGUST...WITH HIGHS RANGING FROM PERHAPS THE UPPER 60S ALONG THE
LAKE MICHIGAN SHORE...TO THE LOW-MID 70S IN THE WARMEST INLAND
REACHES SUCH AS DIXON/PONTIAC. DEW POINT TEMPS IN THE MID-UPPER 40S
WILL MAKE FOR DRY CONDITIONS THIS AFTERNOON AS WELL...AS WINDS BEGIN
TO DIMINISH WITH THE GRADIENT GRADUALLY WEAKENING WITH THE APPROACH
OF THE HIGH PRESSURE CENTER.
RATZER
&&
.PREV DISCUSSION...
327 AM CDT
WITH EXPANSIVE SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTHWEST
AND THEN ESTABLISHING ITSELF OVER THE GREAT LAKES REGION THROUGH THE
WEEKEND...THERE ARE NO REAL WEATHER CONCERNS FOR THE AREA.
HOWEVER...AN UNSEASONABLY COOL AIR MASS IS PLUNGING SOUTH DOWN LAKE
MICHIGAN BEHIND A SECONDARY COLD FRONT AND SHARP TROUGH AXIS SEEN
WELL ON WATER VAPOR IMAGERY EARLY THIS MORNING. THIS WILL QUICKLY
TRANSPORT THE MID SINGLE DIGIT 850 MB TEMPS OVER ONTARIO ON THE 00Z
RAOB TO OUR AREA BY THIS AFTERNOON...WHICH WILL MAKE FOR MORE
FALL-LIKE THAN SUMMER-LIKE HIGH TEMPERATURES PRIMARILY IN THE LOWER
70S...WITH A SCATTERING OF MID 70S READINGS IN THE FAR SOUTH AND
WEST. DESPITE A VERY DRY AIRMASS...STEEPENING LOW LEVEL LAPSE RATES
AND NEAR SATURATION AT ABOUT 800 MB WILL LIKELY RESULT IN A
BLOSSOMING STRATOCU DECK BY MID TO LATE MORNING THAT WILL GRADUALLY
DISSIPATE THROUGH THE EVENING.
IN ADDITION...FORECAST SOUNDINGS INDICATE FAVORABLE PROFILES FOR
GENERATION OF LAKE EFFECT CLOUDS WHICH ARE EXPECTED TO BE CARRIED ON
STRONG NORTHERLY FLOW INTO NEAR LAKE AREAS OF NORTHWEST
INDIANA...WHICH WILL LIMIT HIGHS THERE TO THE UPPER 60S. NORTHEAST
ILLINOIS MAY SEE A BIT OF A SHADOWING EFFECT TO KEEP CLOUD COVER AT
A MINIMUM FOR A TIME...BUT THE LAKESHORE WILL STILL STRUGGLE TO
REACH 70 DEGREES. ADDING TO THE FALL-LIKE FEEL WILL BE GUSTY
NORTH-NORTHEAST WINDS...STRONGEST NEAR THE LAKEFRONT...THANKS TO
A TIGHT PRESSURE GRADIENT AND THE UNSTABLE CONDITIONS OVER THE
LAKE. THOSE THAT BRAVE THE COOL CONDITIONS TO HEAD TO THE BEACH
WILL BE GREETED BY HIGH WAVES AND DANGEROUS CURRENTS...SO SWIMMING
IS STRONGLY DISCOURAGED.
TONIGHT...WINDS WILL QUICKLY DIMINISH AS THE HIGH BUILDS IN AND
SKIES SHOULD CLEAR FOR MOST AREAS AFTER ANY LINGERING EVENING
STRATOCU. THIS WILL SET THE STAGE FOR VERY CHILLY CONDITIONS IN
RURAL AND OUTLYING SUBURBAN AREAS WHERE UPPER 40S ARE EXPECTED AND
EVEN A FEW MID 40S ARE POSSIBLE. THE CHICAGO HEAT ISLAND WILL DROP
TO NEAR 60 DEGREES. THE EXCEPTION TO THE ABOVE WILL BE THE
NORTHWEST INDIANA AND POSSIBLY FAR EAST AND SOUTHEAST COOK COUNTY
LAKEFRONT...WHERE FAVORABLE LAKE EFFECT CONDITIONS WILL CONTINUE
TO EXIST AND RESULTANT CLOUD COVER WILL KEEP TEMPERATURES MILDER.
CONSIDERED PUTTING IN A SLIGHT CHANCE POP FOR LAKE EFFECT SHRA BUT
HELD OFF AND WILL ALLOW THE DAY SHIFT TO ASSESS...AS THE AIR MASS
MOVING OVER THE LAKE IS VERY DRY.
ON WEDNESDAY AND BEYOND...INVERSION LEVELS WILL DROP AS MID LEVEL
HEIGHTS RISE...SO ANY LAKE EFFECT CLOUDS WILL LIKELY DIMINISH
EARLY...BUT EXPECT TO SEE BLOSSOMING CUMULUS AGAIN BY LATE MORNING.
850 MB TEMPERATURES WILL BE CLOSE TO TODAY...BUT 925 MB TEMPS WILL
RISE TO SUPPORT A FEW DEGREE RISE IN HIGH TEMPERATURES. THE
CONTINUED GRADUAL DEPARTURE OF THE DEEP TROUGH OVER EASTERN CANADA
AND THE GREAT LAKES WILL RESULT IN WARMING THERMAL PROFILES ON
THURSDAY...SO AFTER ANOTHER CLEAR AND CHILLY NIGHT...SOME LOCATIONS
MAY TAG 80 DEGREES. THE SLOW WARMING TREND WILL THEN CONTINUE
THROUGH THE WEEKEND INTO EARLY NEXT WEEK...WITH HIGHS IN THE MID 80S
OR EVEN WARMER POSSIBLY BY MONDAY. THE SOUTHEASTERN CWA COULD SEE
ENOUGH MOISTURE RETURN BEHIND HIGH PRESSURE FINALLY SHIFTING TO THE
EAST FOR A LIMITED THREAT FOR TSRA BY MONDAY OR POTENTIALLY AS EARLY
AS SUNDAY...BUT OTHERWISE THE DRY PATTERN MOST OF THE AREA HAS BEEN
IN SINCE THE BEGINNING OF JULY WILL CONTINUE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* STRONG/GUSTY NORTH/NORTHEAST WINDS THROUGH EARLY THIS EVENING.
* HIGH MVFR CIGS POSSIBLE THROUGH LATE MORNING/EARLY AFTERNOON.
CMS
//DISCUSSION...UPDATED 12Z...
TRICKY CLOUD AND WIND FORECAST FOR TERMINALS NEAR LAKE MICHIGAN
THIS MORNING. HIGH PRESSURE IS BUILDING IN FROM THE NORTH
PROVIDING COOLER AIR AND A NORTHERLY WIND FETCH DOWN LAKE
MICHIGAN. THIS HAS ALLOWED MVFR LAKE STRATUS TO DEVELOP AND REACH
THE ILLINOIS AND INDIANA SHORELINES. EXPECT THAT ORD/MDW WILL HAVE
A PERIOD OF SCT-BKN MVFR CLOUDS THIS MORNING BUT ITS NOT CLEAR HOW
LONG THEY WILL LINGER. GYY WILL LIKELY REMAIN BKN THROUGH THE
MORNING AND COULD DO SO THROUGH MUCH OF THE AFTERNOON AS WELL.
THE OTHER CHALLENGE WILL BE WINDS. LATEST SFC OBS AROUND THE LAKE
SUGGEST SOME CONVERGENCE IS SETTING UP ALONG THE WESTERN LAKESHORE
AS EVIDENCED BY SHORELINE WINDS TURNING NNW FROM THEIR EARLIER NE
DIRECTION. EXPECT THAT A SHIFT TO NNE OR NE WILL OCCUR YET THIS
MORNING BUT HAVE LOW CONFIDENCE IN HOW QUICKLY THIS WILL HAPPEN.
THIS MAY ALSO SERVE TO KEEP STRATUS IN PLACE AT ORD/MDW LONGER BUT
BASES WOULD LIKELY RISE TO LOWER END VFR LEVELS. OTHERWISE AREAS
AWAY FROM THE LAKE WILL BE MORE NORTHEASTERLY.
HIGH PRESSURE WILL BE JUST ABOUT OVER THE AREA THIS EVENING WHICH
WILL ALLOW WINDS TO DIMINISH. LAKE EFFECT PARAMETERS WILL STILL BE
FAVORABLE SO WILL NEED TO WATCH CLOUD TRENDS THROUGH THE AFTERNOON
BUT EXPECT GYY TO BE THE MAIN TERMINAL AFFECTED WITH LAKE CLOUDS
AS LOW/MID LEVEL WINDS WILL BE TURNING A BIT MORE NORTHWESTERLY
SUGGESTING ORD/MDW MAY REMAIN WEST OF THE CLOUDS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THROUGH THE PERIOD.
* MEDIUM FOR MVFR CIGS THIS MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH MONDAY...VFR.
MDB
&&
.MARINE...
300 AM CDT
A SERIES OF COLD FRONTS HAS NOW PUSHED SOUTH OF LAKE MICHIGAN WITH A
FAIRLY TIGHT PRESSURE GRADIENT POSITIONED ACROSS THE LAKE WITH LOW
PRESSURE TO THE EAST OVER EASTERN ONTARIO AND A STRONG HIGH PRESSURE
SYSTEM TO THE WEST FROM MANITOBA ACROSS THE DAKOTAS. NORTH TO
NORTHEAST WINDS HAVE INCREASED ACROSS THE LAKE AND WILL REMAIN
STRONG THROUGH LATE AFTERNOON AT WHICH POINT SPEEDS WILL BEGIN TO
GRADUALLY EASE AS THE PRESSURE GRADIENT SLACKENS. WESTERN AND
NORTHERN SECTIONS OF THE LAKE WILL SEE WINDS DIMINISHING FIRST AS
THE GRADIENT WILL BE WEAKENING FROM NORTHWEST TO SOUTHEAST. WAVES
WILL CONTINUE TO BUILD THIS MORNING WITH THE LONG FETCH DIRECTING
THEM AT THE SOUTHERN SHORELINES. HAVE BUMPED WAVES UP TO 5 TO 8 FT
WITH OCCASIONAL 12 FT FOR THE SOUTHERN PARTS OF THE LAKE WITH WELL
EXPOSED BUOYS NEAR THE END OF THE DEVELOPING FETCH ALREADY SHOWING
WAVES IN THE 4 TO 6 FT RANGE...WITH A FEW PEAKS CLOSER TO 7 FT. WILL
CONTINUE WITH THE SMALL CRAFT ADVISORY AS-IS. THE HIGH WILL MOVE
SOUTHWARD AND SETTLE INTO ILLINOIS INTO WEDNESDAY AND THEN GRADUALLY
SPREAD EASTWARD ACROSS THE OHIO VALLEY THROUGH THE END OF THE WEEK.
NORTHERLY WINDS WILL LIKELY TURN ONSHORE WEDNESDAY WITH THE WEAK
PRESSURE GRADIENT IN PLACE BEFORE SHIFTING TO SOUTHERLY ACROSS MOST
OF THE LAKE WEDNESDAY NIGHT AS THE HIGH SHIFTS. SOUTHWEST TO WEST
WINDS ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK BUT ONSHORE
FLOW WILL LIKELY SET UP ACROSS SOUTHERN PARTS OF THE LAKE WHERE THE
PRESSURE GRADIENT WILL REMAIN WEAK INTO THE WEEKEND.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 AM WEDNESDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
951 AM CDT Tue Aug 13 2013
.DISCUSSION...
ISSUED 950 AM CDT Tue Aug 13 2013
Large shield of cirrus clouds continues to push eastward this
morning, but has been showing some thinning as of late. Have had
quite a bit of stratus over the southeast CWA which is a bit
stubborn to erode, and a narrow band has also been quickly
dropping southwest toward the I-74 corridor as cooler and drier
air works its way toward our area. The diurnal cumulus should
start forming over the next couple hours, but latest CU-rule off
the RAP model diminishes this from north to south as the drier air
aloft mixes downward, so sunshine should be on the increase during
the afternoon.
Have made the usual minor hourly temperature adjustments for
today, which generally did not impact the high temperature
forecasts. Also refreshed the zone forecasts to remove mention of
morning fog in the eastern CWA, although little change was needed
otherwise.
Geelhart
&&
.AVIATION...
ISSUED 654 AM CDT Tue Aug 13 2013
IFR/MVFR fog will affect CMI through around 14z-15z, then dissipate
as dry air above the surface mixes down and surface dew point
spreads increase with daytime heating. High pressure will prevail
the remaining time of this TAF period, with VFR conditions. Light
north winds will become NNE and increase to 10-12kt by late
morning.
Diurnal clouds may thicken across our eastern areas, partially due
to some Lake Michigan moisture affects. Cu rule params show -1 to
-3 in that area as well, so we included a BKN040 cloud deck during
the day for CMI/BMI. There may be periods of SCT instead of BKN, but
we wanted to show the trend.
Shimon
&&
.PREV DISCUSSION...
ISSUED 253 AM CDT Tue Aug 13 2013
SHORT TERM...Today through Thursday
07z/2am surface analysis shows cold front settling southward
toward the Ohio River...with bulk of remaining convection now well
to the south across far southern Indiana into Kentucky. Despite
frontal passage and light northerly flow, air mass remains rather
humid across central Illinois. Surface dew points are still in the
middle to upper 60s across most of the area, with drier upper 50s
beginning to filter into the far north around Galesburg. Due to
mostly clear skies and light winds, this lingering low-level
moisture is producing some patchy fog around the area. Will
include fog mention in the forecast this morning, mainly for
locations south of I-72 where moisture will linger longest. After
any early morning fog dissipates, mostly sunny and cool weather
will be the rule today. Secondary cold front will allow very cool
air mass to pour southward into Illinois today, with 850mb temps
expected to drop into the 8 to 10C range. Numeric guidance is
suggesting highs only in the lower to middle 70s: however, based
on upstream readings yesterday afternoon and strength of mid-August
sun, think this is too cool. Will go several degrees above
guidance, with highs ranging from the middle 70s far north...to
the lower 80s along and south of I-70.
Clear skies and light winds will allow excellent radiational
cooling conditions to develop tonight, resulting in chilly
overnight lows in the upper 40s and lower 50s. With high pressure
remaining overhead, the cool/dry weather will continue on
Wednesday and Thursday as well, with highs in the middle to upper
70s and lows mainly in the 50s.
LONG TERM...Friday through Monday
Short-wave currently evident on water vapor imagery over Oregon
will track up and over the western CONUS ridge and into the
Midwest by the end of the week. This feature may trigger scattered
showers/thunder across Iowa and Nebraska Thursday night: however,
by the time it arrives in the drier air mass across Illinois, am
expecting only a slight increase in cloud cover on Friday. The
wave will act to amplify the existing long-wave trough in place
across the eastern CONUS this weekend into early next week. 00z
Aug 13 models continue to suggest the amplifying trough will
eventually lead to the development of an inverted surface trough
across the Ohio River Valley Sunday/Monday. This is the second
straight day models have latched onto this solution, so confidence
is growing that disturbed weather may develop to the E/SE early
next week. GFS/ECMWF spread a few showers into east-central/southeast
Illinois Sunday and Monday...however GEM tends to keep precip a
bit further east across Indiana. Will increase cloud cover and carry
a slight chance POP east of I-57 accordingly. Air mass will slowly
moderate through the period...with high temperatures climbing back
into the lower to middle 80s by Sunday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
636 PM MDT WED AUG 14 2013
.UPDATE...
ISSUED AT 636 PM MDT WED AUG 14 2013
ADJUSTED POPS/SKY FORECAST BASED ON LATEST RADAR TRENDS AND
RAP/HRRR. DECREASED POPS ACROSS MOST OF THE CWA THROUGH THE EARLY
EVENING...WITH INCREASING CHANCES AFTER 03Z AS ACTIVITY OVER NE
COLORADO DROPS SOUTH. STILL NOT SURE HOW FOG WILL PLAY OUT
TONIGHT...WITH ANY LINGERING THUNDERSTORMS AND OUTFLOW
COMPLICATING FORECAST. WILL KEEP PATCHY FOG MENTION TIED TO THE
EAST...HOWEVER MIGHT NEED TO EXPAND IF IT LOOKS LIKE ACTIVITY
UPSTREAM WILL FALL APART SOONER THAN GUIDANCE WOULD INDICATE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 103 PM MDT WED AUG 14 2013
THE AIR MASS OVER THE FORECAST AREA HAS BECOME UNSTABLE WITH MIXED
LAYER CAPES AROUND 1000 J/KG. VISIBLE SATELLITE IMAGERY AND RADAR
SHOWS STORMS FORMING ON AN OUTFLOW BOUNDARY FROM CONVECTION LAST
NIGHT...MAINLY FROM BURLINGTON COLORADO TO SCOTT CITY KANSAS. MID
LEVEL SHEAR IS NOT IMPRESSIVE...SO EXPECT THESE STORMS TO PRODUCE
HEAVY RAIN AND SMALL HAIL. PARTS OF YUMA AND KIT CARSON COUNTIES
RECEIVED HEAVY RAIN LAST NIGHT. CONSIDERED A FLASH FLOOD WATCH FOR
THOSE AREAS...BUT 700 MB THETA/E AXIS IS TOO FAR WEST AND A
SUBTROPICAL CONNECTION IS NOT APPARENT FROM WATER VAPOR. IF STORMS
FORM THERE...HOWEVER...WILL HAVE TO MONITOR FOR FLOODING GIVEN SLOW
STORM MOTION. OTHERWISE...WILL KEEP A CHANCE OF CONVECTION OVER THE
ENTIRE FORECAST AREA GIVEN THE INSTABILITY. WITH LACK OF DIFFERENTIAL
CYCLONIC VORTICITY ADVECTION...CONVECTION WILL END BY 06Z. DEW
POINT DEPRESSIONS EAST OF HIGHWAY 83 WILL BE LOW ENOUGH TO ADD
PATCHY FOG TO THE FORECAST.
THERE IS A BETTER CHANCE FOR SEVERE CONVECTION THURSDAY AFTERNOON AND
EVENING. AS 500 MB RIDGE AMPLIFIES OVER THE ROCKY MOUNTAIN STATES..A
VORTICITY LOBE WILL MOVE ACROSS THE CENTRAL PLAINS BETWEEN 18Z-00Z.
EXPECT BEST LIFT TO BE ACROSS THE EASTERN HALF OF THE REGION WHERE
THE 0-6KM SHEAR WILL EXCEED 45 KNOTS. A WEAK FRONT WILL ALSO BE
POSITIONED ALONG INTERSTATE 70 PROVIDING SURFACE CONVERGENCE.
FINALLY...A 250 MB WIND MAX...THOUGH NOT IMPRESSIVE...WILL EXTEND
OVER WESTERN KANSAS. WITH THESE PARAMETERS IN PLACE...SEVERE WEATHER
IS LIKELY ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 223 PM MDT WED AUG 14 2013
FORECAST PROBLEMS WILL BE CHANCE OF PRECIPITATION THURSDAY NIGHT...
FOG POSSIBILITIES...AND HOW MUCH TO WARM TO MAKE MAXES AS AREA LOOKS
TO SEE A DRY PERIOD. SATELLITE SHOWING AN AMPLIFIED PATTERN FROM
CENTRAL PACIFIC INTO EASTERN NORTH AMERICA. AREA IS UNDER NORTHWEST
FLOW ALOFT WITH A RATHER STRONG SHORTWAVE TROUGH OVER MONTANA. FRONT
REMAINS DRAPED TO OUR WEST AND WELL TO THE SOUTH.
TO START OUT AT MID LEVELS...THE GFS WAS DOING A LITTLE BETTER THAN
THE UKMET OVERALL. ECMWF WAS DOING WELL ON THE TROUGH IN MONTANA.
NAM WAS PERFORMING THE WORST. THE SREF WAS DOING SLIGHTLY BETTER THAN
THE ECMWF ON THE SURFACE FIELD. THE CANADIAN AND UKMET WERE DOING
THE BEST ON THE LOW LEVEL THERMAL FIELD.
THURSDAY NIGHT...AS STATED ABOVE...FRONT WILL BE OVER THE AREA. ALSO
SHORTWAVE TROUGH IN NORTHWEST FLOW WILL BE MOVING THROUGH. ANALYSIS
AND PROGS SHOW THAT A DECENT PV ANOMALY IS ASSOCIATED WITH THIS
SHORTWAVE TROUGH. LEFT FRONT QUADRANT STARTS OUT OVER THE WESTERN
PORTION OF THE AREA AND WORKS ITS WAY SOUTH AND EAST THROUGH THE
NIGHT. BEST LIFT AND INSTABILITY WILL RESIDE ALONG AND TO THE EAST
OF THE COLORADO BORDER. PRECIPITATION CHANCES LOOK TO INCREASE THE
FURTHER EAST AND SOUTH YOU GO. TO TIERED THE POPS IN THAT FASHION.
THUNDERSTORMS SHOULD END NEAR OR SHORTLY AFTER MIDNIGHT.
BOUNDARY LAYER RH INCREASES IN THE LATER HALF OF THE NIGHT PER ALL
MODEL GUIDANCE. SO WILL INSERT FOG AND INCREASE SKY COVER. OVERNIGHT
TEMPERATURES HAVE BEEN ON THE COOL SIDE. SO SIDED WITH THE BETTER
PERFORMING AND COOLER GUIDANCE.
FRIDAY/FRIDAY NIGHT...FOG AND STRATUS COULD LINGER FOR A SIGNIFICANT
AMOUNT OF THE MORNING WITH LIGHT AND VARIABLE WINDS/EASTERLY
WINDS/LITTLE MIXING EXPECTED. MID/UPPER LEVEL RIDGE AND DRIER/WARMER
MID LEVEL AIR BUILDS INTO THE REGION. THIS WILL KEEP THE AREA DRY.
PER COOLER NWP/2 METER FORECASTS/BIAS ADJUSTMENT ON BETTER PERFORMING
850 MB TEMPERATURES...DID LOWER MAXES. HOWEVER...HOW FAST FOG AND
STRATUS BURN OFF WILL DETERMINE HOW WARM THE MAXES GET. FOR THE
NIGHT...SOUTHERLY WINDS ARE STRONGER...ESPECIALLY IN THE WEST.
BOUNDARY LAYER RH PROGS ARE DRIER SO AT THIS TIME WILL LEAVE ANY
MENTION OF FOG OUT ALTHOUGH THERE MAY BE PATCHY AROUND. OVERNIGHT
LOWS SHOULD BE WARMER ESPECIALLY IN THE WEST WITH THE STRONGER WINDS.
LOOKS TO BE COOLER IN THE EAST WITH THE LIGHTER WINDS.
SATURDAY...MID/UPPER LEVEL RIDGE CONTINUES TO BUILD INTO THE AREA
WITH CONTINUED DRY AND WARMER AIR ALOFT. SO DRY FORECAST CONTINUED.
LEE TROUGH STRENGTHENS DURING THE DAY. INCREASING PRESSURE GRADIENT
AND 3 HOUR PRESSURE FALLS WOULD INDICATE CONDITIONS NEARING BREEZY.
SATURDAY NIGHT THROUGH WEDNESDAY...MID/UPPER LEVEL RIDGE IS STILL IN
PLACE BUT THERE ARE DIFFERENCES IN PLACEMENT OF THE AXIS AND
AMPLITUDE. ALTHOUGH IT HAS BACKED OFF A LITTLE...THE LATEST ECMWF
STILL IS KEEPING THE IDEA OF THE RIDGE BEING DISPLACED TO THE EAST
AND FLATTENED BUY A SHORTWAVE TROUGH MOVING IN FROM THE WEST. THE
GFS AND CANADIAN PLUS ENSEMBLE OUTPUT KEEP THE IDEA OF A STRONGER
RIDGE IN PLACE.
DESPITE THOSE DIFFERENCES...THE CANADIAN AND GFS DO INDICATE THE
POSSIBILITY OF WEAK SHORTWAVE TROUGHS COMING ACROSS THE TOP OF THE
RIDGE IN THE WEAK FLOW ALOFT. THE CRH_INIT GRIDS GIVE ME A SLIGHT
CHANCE TO LOW CHANCE OF PRECIPITATION BEGINNING ON SUNDAY NIGHT.
DETERMINISTIC QPF IS LOW WITH THE GEFS PROBABILITIES SUPPORTING
THIS SAME POSSIBILITY. BELIEVE THE ECMWF IS TOO AGGRESSIVE WITH ITS
SOLUTION. HOWEVER...BECAUSE OF THE WHAT THE DETERMINISTIC AND
ENSEMBLE OUTPUT IS SHOWING...THE INIT GRIDS LOOK REASONABLE AND FIT
WITH CLIMATOLOGY AS WELL AND WILL NOT CHANGE THEM. TEMPERATURE OUTPUT
IS ALSO REASONABLE AND FITS WITH CLIMATOLOGY AS WELL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 513 PM MDT WED AUG 14 2013
CURRENTLY MONITORING ISO-SCT THUNDERSTORM ACTIVITY...WITH SEVERAL
STORMS NEARING VICINITY OF BOTH KGLD AND KMCK TERMINALS. WENT
AHEAD AND ADDED VCTS GROUPS THROUGH 03Z...AND WILL CONTINUE TO
MONITOR TRENDS FOR POTENTIAL IMPACT AT TERMINALS. SHORT RANGE
GUIDANCE GENERALLY SUPPORTS THIS ACTIVITY SHIFTING SOUTH AND EAST
OF THE TERMINALS AROUND 03Z...THOUGH LATEST HRRR DOES SHOW AN
ADDITIONAL THUNDERSTORM COMPLEX OVER NORTHERN COLORADO DROPPING
SOUTH AFTER 06Z. NOT A LOT OF CONFIDENCE YET IN THIS LATE NIGHT
CONVECTION SO I LEFT MENTION OUT FOR NOW.
GUIDANCE CONTINUES TO SHOW FOG/STRATUS DEVELOPMENT...AND AS LONG
AS THUNDERSTORM/MID LEVEL CLOUDS CLEAR WE SHOULD SEE FAVORABLE
CONDITIONS FOR THIS. NAM/MET STILL FAVORS EASTERN LOCATIONS
REACHING LIFR CONDITIONS BY 12Z (INCLUDING KMCK). LATEST SHORT
RANGE GUIDANCE IS HINTING AT WESTERN DEVELOPMENT OF THESE LOWER
CONDITIONS AS WELL...SO I CANT RULE OUT IFR/LIFR AT KGLD. WILL
WAIT AND SEE HOW THIS EVENINGS THUNDERSTORM ACTIVITY TRENDS BEFORE
MAKING LOWER CONDITIONS PREVAILING AT EITHER TERMINAL...SINCE THIS
COULD LIMIT FOG DEVELOPMENT LIKE LAST NIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...MENTZER
LONG TERM...BULLER
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
513 PM MDT WED AUG 14 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 103 PM MDT WED AUG 14 2013
THE AIR MASS OVER THE FORECAST AREA HAS BECOME UNSTABLE WITH MIXED
LAYER CAPES AROUND 1000 J/KG. VISIBLE SATELLITE IMAGERY AND RADAR
SHOWS STORMS FORMING ON AN OUTFLOW BOUNDARY FROM CONVECTION LAST
NIGHT...MAINLY FROM BURLINGTON COLORADO TO SCOTT CITY KANSAS. MID
LEVEL SHEAR IS NOT IMPRESSIVE...SO EXPECT THESE STORMS TO PRODUCE
HEAVY RAIN AND SMALL HAIL. PARTS OF YUMA AND KIT CARSON COUNTIES
RECEIVED HEAVY RAIN LAST NIGHT. CONSIDERED A FLASH FLOOD WATCH FOR
THOSE AREAS...BUT 700 MB THETA/E AXIS IS TOO FAR WEST AND A
SUBTROPICAL CONNECTION IS NOT APPARENT FROM WATER VAPOR. IF STORMS
FORM THERE...HOWEVER...WILL HAVE TO MONITOR FOR FLOODING GIVEN SLOW
STORM MOTION. OTHERWISE...WILL KEEP A CHANCE OF CONVECTION OVER THE
ENTIRE FORECAST AREA GIVEN THE INSTABILITY. WITH LACK OF DIFFERENTIAL
CYCLONIC VORTICITY ADVECTION...CONVECTION WILL END BY 06Z. DEW
POINT DEPRESSIONS EAST OF HIGHWAY 83 WILL BE LOW ENOUGH TO ADD
PATCHY FOG TO THE FORECAST.
THERE IS A BETTER CHANCE FOR SEVERE CONVECTION THURSDAY AFTERNOON AND
EVENING. AS 500 MB RIDGE AMPLIFIES OVER THE ROCKY MOUNTAIN STATES..A
VORTICITY LOBE WILL MOVE ACROSS THE CENTRAL PLAINS BETWEEN 18Z-00Z.
EXPECT BEST LIFT TO BE ACROSS THE EASTERN HALF OF THE REGION WHERE
THE 0-6KM SHEAR WILL EXCEED 45 KNOTS. A WEAK FRONT WILL ALSO BE
POSITIONED ALONG INTERSTATE 70 PROVIDING SURFACE CONVERGENCE.
FINALLY...A 250 MB WIND MAX...THOUGH NOT IMPRESSIVE...WILL EXTEND
OVER WESTERN KANSAS. WITH THESE PARAMETERS IN PLACE...SEVERE WEATHER
IS LIKELY ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 223 PM MDT WED AUG 14 2013
FORECAST PROBLEMS WILL BE CHANCE OF PRECIPITATION THURSDAY NIGHT...
FOG POSSIBILITIES...AND HOW MUCH TO WARM TO MAKE MAXES AS AREA LOOKS
TO SEE A DRY PERIOD. SATELLITE SHOWING AN AMPLIFIED PATTERN FROM
CENTRAL PACIFIC INTO EASTERN NORTH AMERICA. AREA IS UNDER NORTHWEST
FLOW ALOFT WITH A RATHER STRONG SHORTWAVE TROUGH OVER MONTANA. FRONT
REMAINS DRAPED TO OUR WEST AND WELL TO THE SOUTH.
TO START OUT AT MID LEVELS...THE GFS WAS DOING A LITTLE BETTER THAN
THE UKMET OVERALL. ECMWF WAS DOING WELL ON THE TROUGH IN MONTANA.
NAM WAS PERFORMING THE WORST. THE SREF WAS DOING SLIGHTLY BETTER THAN
THE ECMWF ON THE SURFACE FIELD. THE CANADIAN AND UKMET WERE DOING
THE BEST ON THE LOW LEVEL THERMAL FIELD.
THURSDAY NIGHT...AS STATED ABOVE...FRONT WILL BE OVER THE AREA. ALSO
SHORTWAVE TROUGH IN NORTHWEST FLOW WILL BE MOVING THROUGH. ANALYSIS
AND PROGS SHOW THAT A DECENT PV ANOMALY IS ASSOCIATED WITH THIS
SHORTWAVE TROUGH. LEFT FRONT QUADRANT STARTS OUT OVER THE WESTERN
PORTION OF THE AREA AND WORKS ITS WAY SOUTH AND EAST THROUGH THE
NIGHT. BEST LIFT AND INSTABILITY WILL RESIDE ALONG AND TO THE EAST
OF THE COLORADO BORDER. PRECIPITATION CHANCES LOOK TO INCREASE THE
FURTHER EAST AND SOUTH YOU GO. TO TIERED THE POPS IN THAT FASHION.
THUNDERSTORMS SHOULD END NEAR OR SHORTLY AFTER MIDNIGHT.
BOUNDARY LAYER RH INCREASES IN THE LATER HALF OF THE NIGHT PER ALL
MODEL GUIDANCE. SO WILL INSERT FOG AND INCREASE SKY COVER. OVERNIGHT
TEMPERATURES HAVE BEEN ON THE COOL SIDE. SO SIDED WITH THE BETTER
PERFORMING AND COOLER GUIDANCE.
FRIDAY/FRIDAY NIGHT...FOG AND STRATUS COULD LINGER FOR A SIGNIFICANT
AMOUNT OF THE MORNING WITH LIGHT AND VARIABLE WINDS/EASTERLY
WINDS/LITTLE MIXING EXPECTED. MID/UPPER LEVEL RIDGE AND DRIER/WARMER
MID LEVEL AIR BUILDS INTO THE REGION. THIS WILL KEEP THE AREA DRY.
PER COOLER NWP/2 METER FORECASTS/BIAS ADJUSTMENT ON BETTER PERFORMING
850 MB TEMPERATURES...DID LOWER MAXES. HOWEVER...HOW FAST FOG AND
STRATUS BURN OFF WILL DETERMINE HOW WARM THE MAXES GET. FOR THE
NIGHT...SOUTHERLY WINDS ARE STRONGER...ESPECIALLY IN THE WEST.
BOUNDARY LAYER RH PROGS ARE DRIER SO AT THIS TIME WILL LEAVE ANY
MENTION OF FOG OUT ALTHOUGH THERE MAY BE PATCHY AROUND. OVERNIGHT
LOWS SHOULD BE WARMER ESPECIALLY IN THE WEST WITH THE STRONGER WINDS.
LOOKS TO BE COOLER IN THE EAST WITH THE LIGHTER WINDS.
SATURDAY...MID/UPPER LEVEL RIDGE CONTINUES TO BUILD INTO THE AREA
WITH CONTINUED DRY AND WARMER AIR ALOFT. SO DRY FORECAST CONTINUED.
LEE TROUGH STRENGTHENS DURING THE DAY. INCREASING PRESSURE GRADIENT
AND 3 HOUR PRESSURE FALLS WOULD INDICATE CONDITIONS NEARING BREEZY.
SATURDAY NIGHT THROUGH WEDNESDAY...MID/UPPER LEVEL RIDGE IS STILL IN
PLACE BUT THERE ARE DIFFERENCES IN PLACEMENT OF THE AXIS AND
AMPLITUDE. ALTHOUGH IT HAS BACKED OFF A LITTLE...THE LATEST ECMWF
STILL IS KEEPING THE IDEA OF THE RIDGE BEING DISPLACED TO THE EAST
AND FLATTENED BUY A SHORTWAVE TROUGH MOVING IN FROM THE WEST. THE
GFS AND CANADIAN PLUS ENSEMBLE OUTPUT KEEP THE IDEA OF A STRONGER
RIDGE IN PLACE.
DESPITE THOSE DIFFERENCES...THE CANADIAN AND GFS DO INDICATE THE
POSSIBILITY OF WEAK SHORTWAVE TROUGHS COMING ACROSS THE TOP OF THE
RIDGE IN THE WEAK FLOW ALOFT. THE CRH_INIT GRIDS GIVE ME A SLIGHT
CHANCE TO LOW CHANCE OF PRECIPITATION BEGINNING ON SUNDAY NIGHT.
DETERMINISTIC QPF IS LOW WITH THE GEFS PROBABILITIES SUPPORTING
THIS SAME POSSIBILITY. BELIEVE THE ECMWF IS TOO AGGRESSIVE WITH ITS
SOLUTION. HOWEVER...BECAUSE OF THE WHAT THE DETERMINISTIC AND
ENSEMBLE OUTPUT IS SHOWING...THE INIT GRIDS LOOK REASONABLE AND FIT
WITH CLIMATOLOGY AS WELL AND WILL NOT CHANGE THEM. TEMPERATURE OUTPUT
IS ALSO REASONABLE AND FITS WITH CLIMATOLOGY AS WELL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 513 PM MDT WED AUG 14 2013
CURRENTLY MONITORING ISOL-SCT THUNDERSTORM ACTIVITY...WITH SEVERAL
STORMS NEARING VICINITY OF BOTH KGLD AND KMCK TERMINALS. WENT
AHEAD AND ADDED VCTS GROUPS THROUGH 03Z...AND WILL CONTINUE TO
MONITOR TRENDS FOR POTENTIAL IMPACT AT TERMINALS. SHORT RANGE
GUIDANCE GENERALLY SUPPORTS THIS ACTIVITY SHIFTING SOUTH AND EAST
OF THE TERMINALS AROUND 03Z...THOUGH LATEST HRRR DOES SHOW AN
ADDITIONAL THUNDERSTORM COMPLEX OVER NORTHERN COLORADO DROPPING
SOUTH AFTER 06Z. NOT A LOT OF CONFIDENCE YET IN THIS LATE NIGHT
CONVECTION SO I LEFT MENTION OUT FOR NOW.
GUIDANCE CONTINUES TO SHOW FOG/STRATUS DEVELOPMENT...AND AS LONG
AS THUNDERSTORM/MID LEVEL CLOUDS CLEAR WE SHOULD SEE FAVORABLE
CONDITIONS FOR THIS. NAM/MET STILL FAVORS EASTERN LOCATIONS
REACHING LIFR CONDITIONS BY 12Z (INCLUDING KMCK). LATEST SHORT
RANGE GUIDANCE IS HINTING AT WESTERN DEVELOPMENT OF THESE LOWER
CONDITIONS AS WELL...SO I CANT RULE OUT IFR/LIFR AT KGLD. WILL
WAIT AND SEE HOW THIS EVENINGS THUNDERSTORM ACTIVITY TRENDS BEFORE
MAKING LOWER CONDITIONS PREVAILING AT EITHER TERMINAL...SINCE THIS
COULD LIMIT FOG DEVELOPMENT LIKE LAST NIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...MENTZER
LONG TERM...BULLER
AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
328 PM CDT Tue Aug 13 2013
.SHORT TERM...(This Evening through Wednesday)
Issued at 328 PM CDT TUE AUG 13 2013
Upper trough remains over the Great Lakes with a shortwave trough
extending southwestward into eastern Nebraska. This shortwave along
with a well defined MCV in southern Nebraska helped sustain a
cluster of showers and thunderstorms into the far northwest corner
of the CWA this afternoon. However...a drier and more stable
atmosphere over most of the CWA has aided a weakening trend to the
convection and expect any sustained or additional development to
occur in the western or far southern CWA until early evening. At
that time...feel majority of convection...now occurring in central
KS will have advanced further south of the vicinity with the outflow
boundary...similar to the HRRR model. Will therefore carry a dry
forecast for the overnight. Skies may become mostly clear tonight which
would support the possibility of some patchy fog. However...feel the
potential for more high clouds to advance into the area from the
northwest is high enough to negate mentioning fog for now. The dry
air and breaks in the clouds should help lows fall into the lower
60s.
On Wednesday...will maintain a dry CST as the deeper moisture and
axis of higher instability are pushed more to the west of the CWA.
Any convection through the day should remain to the west and north
of the CWA. High temperatures Wednesday will be similar
today...except slightly warmer in the north central with readings in
the lower 80s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 328 PM CDT TUE AUG 13 2013
For Wednesday night through Friday, the models have trended more
along the lines of the NAM with keeping much of the cooler and
dryer air to the northeast of the forecast area. On top of that
instead of a distinct shortwave trough moving through the
northwest flow Thursday night, models have trended towards
bringing several vort maximum through the flow late Wednesday
night through Friday. Because of this have trended min temps
warmer expecting more cloud cover and higher dewpoint temps
through the night. Will also carry a 20 to 30 percent chance pops
through the period. Forecast soundings with the higher dewpoints
show much less inhibition to convection with lower LCL heights.
because of this it is difficult to rule out precip chances with
the expected vort energy moving overhead. The airmass in general
does not change much from today. Therefore expect temps to be
relatively persistent with highs around 80 and lows in the lower
to mid 60s.
Saturday into Monday is expected to be dry with a gradual warming
trend as mid level ridging moves in from the west and insolation
increases. Uncertainty remains in the forecast for next week as
the ECMWF has shown little consistency from run to run over the
last 48 hrs. Think that there will be a small chance for precip
Monday night and Tuesday as the GFS continues to bring a shortwave
trough across the plains. However confidence is not high since the
ECMWF goes back and forth between cutting off an upper low and an
open shortwave.
&&
.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1239 PM CDT TUE AUG 13 2013
Still expect VFR conditions to persist through the forecast as
convection expected to remain west and south of the terminals
through the period. Could see possible fog tonight...but forecast
for high clouds in the area makes confidence in fog potential
low...so will therefore not introduce into at this time. east to
northeast winds will persist generally under 10 kts...but should
slowly veer beyond 12z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...63
LONG TERM...Wolters
AVIATION...63
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
1243 PM CDT Tue Aug 13 2013
.UPDATE...
Issued at 724 AM CDT TUE AUG 13 2013
The thunderstorm complex over central Nebraska continues to build
toward the south southeast this morning. In the past hour, a
segment of this complex began to forward propagate with more of a
southeasterly direction. Instability is limited but does exist
along the highway 81 corridor, and recent RAP runs suggest that it
may increase to around 1000 J/Kg by mid morning. This would
suggest at least some potential for the system to maintain itself
into parts of north central Kansas. Have increased precip chances
to around 40 percent, but still see potential for the complex to
weaken, remain west of the forecast area, or even fall apart
before getting very far into Kansas. Will watch closely as it
evolves now that the sun has risen and instability may or may not
increase.
Barjenbruch
&&
.SHORT TERM...(Today and Tonight)
Issued at 324 AM CDT TUE AUG 13 2013
A ridge of surface high pressure had worked its way into northern
Kansas early this morning, bringing with it a rather stable
airmass. While yet another short wave trough was moving east across
southern Kansas this morning, thunderstorm activity has been confined
south of the forecast area. Between 2 and 4 AM, the thunderstorm
complex has attempted to make a run to the northeast as it pushed
out weak outflow, and has come close to Dickinson and Morris
counties, but the airmass just seems to increase in stability to the
north and the forecast area has remained dry thus far. Another short
wave trough of interest, well defined in water vapor imagery, was
diving south out of the Dakotas and has aided in development of a
thunderstorm complex over north central Nebraska.
This morning, there is still some small chance for the complex over
southern Kansas to send a few storms into the far southern parts of
the forecast area, and have maintained small chances for
thunderstorms in these areas accordingly. This potential may even
linger into the early afternoon hours as the center of the short
wave passes over eastern Kansas. The activity over Nebraska is
forecast to track generally to the south with the bulk of convection
favored on the western flank where it has greater instability to
work with. This should keep this system west of the forecast area,
but included a slight chance for precip generally near and west of
Highway 81 in case it should clip the area. Temperatures will be
similar to, or even a bit cooler than Monday with highs in the lower
80s. Kept the forecast for tonight dry as the surface high would
seem to maintain a hold on the area with a stable airmass, and the
stronger deep forcing and upper support looks to remain south and
west of the forecast area.
Barjenbruch
.LONG TERM...(Wednesday through Monday)
Issued at 324 AM CDT TUE AUG 13 2013
On Wednesday, expansive area of surface high pressure centered
over the Mississippi Valley begins to shift eastward leaving
another dry and pleasant day for the area. Edged high temperatures
during the afternoon into the lower 80s with weak low level winds
and peaks of sunshine expected by the late afternoon period.
Focus returns to the northwest flow aloft on Thursday as another
wave is progged to deepen as it enters the northern plains and dives
southeast. The recent runs of the NAM, GFS, and ECWMF have varying
timing and intensity differences with the GFS being the most
amplified of the group. Almost all solutions have agreed on slight
chances of sct thunderstorms developing ahead of the trough on
Thursday afternoon over north central KS. Otherwise was not
confident to increase rain chances Thursday evening as the main
piece of energy may center just north or east of the area. Continued
the trend from the afternoon package by assuming increasing cloud
cover could leave highs Thursday near the 80 degree mark. Depending
on timing with the main upper level system could still see some
lingering showers and thunderstorms Friday afternoon especially over
east central and northeast portions of KS. Models are beginning to
trend subsidence filling in behind the wave which would bring dry
conditions over north central areas. Will see if this trend
continues in upcoming days.
Looking at the extended period, the weekend continues to look dry
and pleasantly warm as the upper ridge builds into the plains
region. With the weak flow pattern in place, highs in the low 80s
and lows near 60 degrees still appear to be reasonable. Another
shortwave trough entering over the Pacific Northwest suppresses the
ridge as it shifts into the plains region as we head into Monday.
Continued with a dry forecast at this time as low confidence
exists in timing and how deep the wave is progged to be.
Temperatures will greatly depend on the scenario with highs at
this time trying to rise closer to normal values in the middle 80s
and lows in the 60s.
&&
.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1239 PM CDT TUE AUG 13 2013
Still expect VFR conditions to persist through the forecast as
convection expected to remain west and south of the terminals
through the period. Could see possible fog tonight...but fcst for
high clouds in the area makes confidence in fog potential low...so
will therefore not introduce into at this time. east to northeast
winds will persist generally under 10 kts...but should slowly veer
beyond 12z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Barjenbruch
LONG TERM...Bowen
AVIATION...63
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1217 PM CDT Tue Aug 13 2013
...Updated for Aviation...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 420 AM CDT TUE AUG 13 2013
Wednesday:
A 70 kt 250 hPa jet streak will traverse across western Kansas through
the day. At the sfc, an upslope flow regime is expected with weak 850
hPa warm air advection/theta-e advection across far western Kansas.
For spatiotemporal adjustments of precipitation probability percentage
points, have relied heavily on ECMWF output solutions. Wednesday is
shaping up to be another MCS day. Orographic convection is expected
to form across the high plains and then drift southeast across the region
during the late evening and overnight period. The precipitation numerical
values are still in the chance category. The NAM solution is still dry
for the most part - but this model has failed with the MCS events recently,
so I remain dubious of any described solution herein. The tail end of
both WRF cores also support more confidence in the ECMWF solution. Heavy
rain will be possible again as precipitable water values are forecast
around the 75th percentile for a Gaussian distribution. Otherwise, maximums
will be cool because of all the cloud cover and lack of low level downslope
flow. Followed the ECE for guidance, which shows values in the upper
70sF to around 80F. Minimums into Thursday morning will be in the lower
60sF.
Thursday:
Another MCS day is possible Thursday. Upper level flow is more NW during
this period as a result the amplification of 500 hPa ridging across
the spine of the Rockies. This flow may advect any MCS activity farther
east than compared to the previous day. Heavy rain could be a possibility
again, as pwats continue on the higher end of the distribution spectrum.
Maximum surface temperatures could be a few degrees (F) warmer, particularly
across the western zones, as the 850 hPa warm plume advects slightly
farther east. A gradient of upper 80sF to around 80F is expected from
the west to the east with lows in the 60sF.
Friday and beyond:
Stuck with the weighted model solution (allblend) for the rest of the
forecast period as uncertainty continues to increase. There could be
some late afternoon and evening convection across the eastern zones
in association with an enhanced region of 850 hPa frontogenesis that
the ECMWF solutions shows on Friday. A drier forecast is possible next
weekend as the aforementioned 500 hPa ridge amplifies and expands farther
east across the region with a net result of drier northerly flow aloft
and higher mid level geopotential heights. Temperatures will moderate
to near normal during this drier period. Another period of convection
is possible in about a week from now as a trof moves across the northern
prairies. Will continue to tread lightly.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1205 PM CDT TUE AUG 13 2013
As a shortwave trough moves southeastward across south central
Kansas this afternoon, areas of showers and thunderstorms in the
Hays vicinity will move toward KGCK and KDDC by 22z. By 00z expect
the thunderstorm activity to decrease as the shortwave trough moves
east and south.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 40 40 30 40
GCK 77 60 78 62 / 30 30 30 40
EHA 83 60 81 62 / 30 40 40 40
LBL 82 61 80 63 / 30 30 30 40
HYS 76 60 78 60 / 60 30 30 40
P28 78 62 81 64 / 50 60 10 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
739 AM CDT Tue Aug 13 2013
.UPDATE...
Issued at 724 AM CDT TUE AUG 13 2013
The thunderstorm complex over central Nebraska continues to build
toward the south southeast this morning. In the past hour, a
segment of this complex began to forward propagate with more of a
southeasterly direction. Instability is limited but does exist
along the highway 81 corridor, and recent RAP runs suggest that it
may increase to around 1000 J/Kg by mid morning. This would
suggest at least some potential for the system to maintain itself
into parts of north central Kansas. Have increased precip chances
to around 40 percent, but still see potential for the complex to
weaken, remain west of the forecast area, or even fall apart
before getting very far into Kansas. Will watch closely as it
evolves now that the sun has risen and instability may or may not
increase.
Barjenbruch
&&
.SHORT TERM...(Today and Tonight)
Issued at 324 AM CDT TUE AUG 13 2013
A ridge of surface high pressure had worked its way into northern
Kansas early this morning, bringing with it a rather stable
airmass. While yet another short wave trough was moving east across
southern Kansas this morning, thunderstorm activity has been confined
south of the forecast area. Between 2 and 4 AM, the thunderstorm
complex has attempted to make a run to the northeast as it pushed
out weak outflow, and has come close to Dickinson and Morris
counties, but the airmass just seems to increase in stability to the
north and the forecast area has remained dry thus far. Another short
wave trough of interest, well defined in water vapor imagery, was
diving south out of the Dakotas and has aided in development of a
thunderstorm complex over north central Nebraska.
This morning, there is still some small chance for the complex over
southern Kansas to send a few storms into the far southern parts of
the forecast area, and have maintained small chances for
thunderstorms in these areas accordingly. This potential may even
linger into the early afternoon hours as the center of the short
wave passes over eastern Kansas. The activity over Nebraska is
forecast to track generally to the south with the bulk of convection
favored on the western flank where it has greater instability to
work with. This should keep this system west of the forecast area,
but included a slight chance for precip generally near and west of
Highway 81 in case it should clip the area. Temperatures will be
similar to, or even a bit cooler than Monday with highs in the lower
80s. Kept the forecast for tonight dry as the surface high would
seem to maintain a hold on the area with a stable airmass, and the
stronger deep forcing and upper support looks to remain south and
west of the forecast area.
Barjenbruch
.LONG TERM...(Wednesday through Monday)
Issued at 324 AM CDT TUE AUG 13 2013
On Wednesday, expansive area of surface high pressure centered
over the Mississippi Valley begins to shift eastward leaving
another dry and pleasant day for the area. Edged high temperatures
during the afternoon into the lower 80s with weak low level winds
and peaks of sunshine expected by the late afternoon period.
Focus returns to the northwest flow aloft on Thursday as another
wave is progged to deepen as it enters the northern plains and dives
southeast. The recent runs of the NAM, GFS, and ECWMF have varying
timing and intensity differences with the GFS being the most
amplified of the group. Almost all solutions have agreed on slight
chances of sct thunderstorms developing ahead of the trough on
Thursday afternoon over north central KS. Otherwise was not
confident to increase rain chances Thursday evening as the main
piece of energy may center just north or east of the area. Continued
the trend from the afternoon package by assuming increasing cloud
cover could leave highs Thursday near the 80 degree mark. Depending
on timing with the main upper level system could still see some
lingering showers and thunderstorms Friday afternoon especially over
east central and northeast portions of KS. Models are beginning to
trend subsidence filling in behind the wave which would bring dry
conditions over north central areas. Will see if this trend
continues in upcoming days.
Looking at the extended period, the weekend continues to look dry
and pleasantly warm as the upper ridge builds into the plains
region. With the weak flow pattern in place, highs in the low 80s
and lows near 60 degrees still appear to be reasonable. Another
shortwave trough entering over the Pacific Northwest suppresses the
ridge as it shifts into the plains region as we head into Monday.
Continued with a dry forecast at this time as low confidence
exists in timing and how deep the wave is progged to be.
Temperatures will greatly depend on the scenario with highs at
this time trying to rise closer to normal values in the middle 80s
and lows in the 60s.
&&
.AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning)
Issued at 621 AM CDT TUE AUG 13 2013
VFR conditions are forecast through the TAF period with light
northeast winds. The only uncertainty would be in some small
potential for vis restrictions after 06Z as shallow fog may
develop.
Barjenbruch
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Barjenbruch
LONG TERM...Bowen
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
600 AM CDT Tue Aug 13 2013
...Update to aviation for 12Z TAFs...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 420 AM CDT TUE AUG 13 2013
Wednesday:
A 70 kt 250 hPa jet streak will traverse across western Kansas through
the day. At the sfc, an upslope flow regime is expected with weak 850
hPa warm air advection/theta-e advection across far western Kansas.
For spatiotemporal adjustments of precipitation probability percentage
points, have relied heavily on ECMWF output solutions. Wednesday is
shaping up to be another MCS day. Orographic convection is expected
to form across the high plains and then drift southeast across the region
during the late evening and overnight period. The precipitation numerical
values are still in the chance category. The NAM solution is still dry
for the most part - but this model has failed with the MCS events recently,
so I remain dubious of any described solution herein. The tail end of
both WRF cores also support more confidence in the ECMWF solution. Heavy
rain will be possible again as precipitable water values are forecast
around the 75th percentile for a Gaussian distribution. Otherwise, maximums
will be cool because of all the cloud cover and lack of low level downslope
flow. Followed the ECE for guidance, which shows values in the upper
70sF to around 80F. Minimums into Thursday morning will be in the lower
60sF.
Thursday:
Another MCS day is possible Thursday. Upper level flow is more NW during
this period as a result the amplification of 500 hPa ridging across
the spine of the Rockies. This flow may advect any MCS activity farther
east than compared to the previous day. Heavy rain could be a possibility
again, as pwats continue on the higher end of the distribution spectrum.
Maximum surface temperatures could be a few degrees (F) warmer, particularly
across the western zones, as the 850 hPa warm plume advects slightly
farther east. A gradient of upper 80sF to around 80F is expected from
the west to the east with lows in the 60sF.
Friday and beyond:
Stuck with the weighted model solution (allblend) for the rest of the
forecast period as uncertainty continues to increase. There could be
some late afternoon and evening convection across the eastern zones
in association with an enhanced region of 850 hPa frontogenesis that
the ECMWF solutions shows on Friday. A drier forecast is possible next
weekend as the aforementioned 500 hPa ridge amplifies and expands farther
east across the region with a net result of drier northerly flow aloft
and higher mid level geopotential heights. Temperatures will moderate
to near normal during this drier period. Another period of convection
is possible in about a week from now as a trof moves across the northern
prairies. Will continue to tread lightly.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 600 AM CDT TUE AUG 13 2013
Afternoon and evening thunderstorms will be possible again today. Cigs
could be reduced in heavier thunderstorm activity, but this will be
very localized. Light and variable winds will become easterly 10 kt
by noon and continuing into this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 60 60 30 40
GCK 77 60 78 62 / 50 50 30 40
EHA 83 60 81 62 / 60 60 40 40
LBL 82 61 80 63 / 70 70 30 40
HYS 76 60 78 60 / 40 30 30 40
P28 78 62 81 64 / 70 70 20 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
420 AM CDT Tue Aug 13 2013
...Update to long term discussion...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 420 AM CDT TUE AUG 13 2013
Wednesday:
A 70 kt 250 hPa jet streak will traverse across western Kansas through
the day. At the sfc, an upslope flow regime is expected with weak 850
hPa warm air advection/theta-e advection across far western Kansas.
For spatiotemporal adjustments of precipitation probability percentage
points, have relied heavily on ECMWF output solutions. Wednesday is
shaping up to be another MCS day. Orographic convection is expected
to form across the high plains and then drift southeast across the region
during the late evening and overnight period. The precipitation numerical
values are still in the chance category. The NAM solution is still dry
for the most part - but this model has failed with the MCS events recently,
so I remain dubious of any described solution herein. The tail end of
both WRF cores also support more confidence in the ECMWF solution. Heavy
rain will be possible again as precipitable water values are forecast
around the 75th percentile for a Gaussian distribution. Otherwise, maximums
will be cool because of all the cloud cover and lack of low level downslope
flow. Followed the ECE for guidance, which shows values in the upper
70sF to around 80F. Minimums into Thursday morning will be in the lower
60sF.
Thursday:
Another MCS day is possible Thursday. Upper level flow is more NW during
this period as a result the amplification of 500 hPa ridging across
the spine of the Rockies. This flow may advect any MCS activity farther
east than compared to the previous day. Heavy rain could be a possibility
again, as pwats continue on the higher end of the distribution spectrum.
Maximum surface temperatures could be a few degrees (F) warmer, particularly
across the western zones, as the 850 hPa warm plume advects slightly
farther east. A gradient of upper 80sF to around 80F is expected from
the west to the east with lows in the 60sF.
Friday and beyond:
Stuck with the weighted model solution (allblend) for the rest of the
forecast period as uncertainty continues to increase. There could be
some late afternoon and evening convection across the eastern zones
in association with an enhanced region of 850 hPa frontogenesis that
the ECMWF solutions shows on Friday. A drier forecast is possible next
weekend as the aforementioned 500 hPa ridge amplifies and expands farther
east across the region with a net result of drier northerly flow aloft
and higher mid level geopotential heights. Temperatures will moderate
to near normal during this drier period. Another period of convection
is possible in about a week from now as a trof moves across the northern
prairies. Will continue to tread lightly.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 100 AM CDT TUE AUG 13 2013
Rain showers and isolated thunderstorms are expected to affect the
TAF locations (DDC, GCK, HYS) through 08-09z time frame.
Thereafter, a weakening trend in activity is expected. Prevailing
winds will be some variation of east through the night and into
the day Tuesday. Some temporary MVFR ceilings will be possible in
the 10-14z time frame...and perhaps some brief IFR. More showers
and thunderstorms are expected by afternoon as the southwest
Kansas region remains in a moist upslope low level pattern.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 60 60 30 40
GCK 77 60 78 62 / 50 50 30 40
EHA 83 60 81 62 / 60 60 40 40
LBL 82 61 80 63 / 70 70 30 40
HYS 76 60 78 60 / 40 30 30 40
P28 78 62 81 64 / 70 70 20 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
334 AM CDT Tue Aug 13 2013
...UPDATED SYNOPSIS AND SHORT TERM SECTION...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 218 PM CDT MON AUG 12 2013
As upper level ridging builds into the Intermountain West,
northwesterly upper level flow will prevail across the Plains into
Friday. Several ripples in the flow will bring slight chances for
showers and thunderstorms into western Kansas, mainly in the late
afternoons and evenings, into Friday Night. The upper level ridge
will slowly move east and weaken into the weekend with mainly dry
conditions and warming temperatures.
At the surface, broad high pressure will be found across the
Mississippi Valley into the Plains with a trough of low pressure
in the lee of the Rockies. Moist south to southeasterly surface
flow will prevail.
Overnight lows will gradually warm from the low 60s into the mid and
upper 60s by the weekend. Daytime highs will warm gradually from the
lower to mid 80s to around 85 to 90 by the weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 100 AM CDT TUE AUG 13 2013
Rain showers and isolated thunderstorms are expected to affect the
TAF locations (DDC, GCK, HYS) through 08-09z time frame.
Thereafter, a weakening trend in activity is expected. Prevailing
winds will be some variation of east through the night and into
the day Tuesday. Some temporary MVFR ceilings will be possible in
the 10-14z time frame...and perhaps some brief IFR. More showers
and thunderstorms are expected by afternoon as the southwest
Kansas region remains in a moist upslope low level pattern.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 60 60 30 40
GCK 77 60 78 62 / 50 50 30 40
EHA 83 60 81 62 / 60 60 40 40
LBL 82 61 80 63 / 70 70 30 40
HYS 76 60 78 60 / 40 30 30 40
P28 78 62 81 64 / 70 70 20 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...KRUSE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS JACKSON KY
124 PM EDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 124 PM EDT TUE AUG 13 2013
INGESTED THE LATEST OBS DATA TO ESTABLISH NEW TRENDS IN THE HOURLY
FORECAST ELEMENTS. ASIDE FROM THAT THE FORECAST WAS ON TRACK WITH NO
MAJOR CHANGES REQUIRED.
UPDATE ISSUED AT 1127 AM EDT TUE AUG 13 2013
UPDATED THE TODAY PERIOD OF THE FORECAST AND THE HAZARDOUS WEATHER
OUTLOOK. UPDATED THE PRECIPITATION PROBABILITIES FOR THE REST OF
TODAY TO REFLECT THE LATEST TRENDS IN RADAR IMAGERY AND MOS GUIDANCE.
REMOVED MORNING AND AFTERNOON WORDING FROM THE ZONE TEXT PRODUCT AND
DECREASED PRECIPITATION CHANCES FOR THE REST OF THE DAY TO THE 30 TO
50 PERCENT CHANCE RANGE. ISOLATED TO SCATTERED SHOWERS AND STORMS ARE
EXPECTED TO MOVE ACROSS THE AREA TODAY AS A COLD FRONT MAKES ITS WAY
EAST. THIS ACTIVITY...AFTERNOON RAMPING UP A BIT LATE THIS
MORNING...IS EXPECTED TO GRADUALLY TAPER OFF DURING THE AFTERNOON AND
EARLY EVENING HOURS. ALSO REMOVED MENTION OF FLOODING AND HEAVY RAIN
FROM THE HAZARDOUS WEATHER OUTLOOK. IT APPEARS THAT THE THREAT FOR
HEAVY RAIN IS FINALLY OVER FOR EASTERN KENTUCKY.
UPDATE ISSUED AT 725 AM EDT TUE AUG 13 2013
UPDATED THE NEAR TERM GRIDS TO REFLECT THE BANDED SHOWERS CROSSING
THE SOUTHEAST PARTS OF THE CWA. ALSO ADJUSTED THE T/TD GRIDS THROUGH
THE NEXT SEVERAL HOURS TO REFLECT THE LATEST OBS AND TRENDS. THE REST
OF THE FORECAST REMAINS ON TRACK. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 124 PM EDT TUE AUG 13 2013
VARIABLE CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THIS
EVENING. SCATTERED SHOWERS AND STORMS ARE EXPECTED TO MOVE ACROSS
EASTERN KENTUCKY THE REST OF TODAY ALONG A DEPARTING COLD FRONT. CIGS
WILL VARY FROM MVFR TO VFR DEPENDING ON THE PROXIMITY OF SHOWERS AND
STORMS TO THE TAF SITES. JKL IN PARTICULAR WILL BE CHALLENGING DUE TO
ITS RIDGETOP LOCATION. SOME MVFR FOG IS EXPECTED TO FORM ACROSS THE
AREA OVERNIGHT...AS SKIES CLEAR OFF AND WINDS DIE DOWN. MOSTLY CLEAR
TO PARTLY CLOUDY SKIES ARE EXPECTED ON WEDNESDAY AS HIGH PRESSURE
SETTLES OVER THE AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
1127 AM EDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 1127 AM EDT TUE AUG 13 2013
UPDATED THE TODAY PERIOD OF THE FORECAST AND THE HAZARDOUS WEATHER
OUTLOOK. UPDATED THE PRECIPITATION PROBABILITIES FOR THE REST OF
TODAY TO REFLECT THE LATEST TRENDS IN RADAR IMAGERY AND MOS GUIDANCE.
REMOVED MORNING AND AFTERNOON WORDING FROM THE ZONE TEXT PRODUCT AND
DECREASED PRECIPITATION CHANCES FOR THE REST OF THE DAY TO THE 30 TO
50 PERCENT CHANCE RANGE. ISOLATED TO SCATTERED SHOWERS AND STORMS ARE
EXPECTED TO MOVE ACROSS THE AREA TODAY AS A COLD FRONT MAKES ITS WAY
EAST. THIS ACTIVITY...AFTERNOON RAMPING UP A BIT LATE THIS
MORNING...IS EXPECTED TO GRADUALLY TAPER OFF DURING THE AFTERNOON AND
EARLY EVENING HOURS. ALSO REMOVED MENTION OF FLOODING AND HEAVY RAIN
FROM THE HAZARDOUS WEATHER OUTLOOK. IT APPEARS THAT THE THREAT FOR
HEAVY RAIN IS FINALLY OVER FOR EASTERN KENTUCKY.
UPDATE ISSUED AT 725 AM EDT TUE AUG 13 2013
UPDATED THE NEAR TERM GRIDS TO REFLECT THE BANDED SHOWERS CROSSING
THE SOUTHEAST PARTS OF THE CWA. ALSO ADJUSTED THE T/TD GRIDS THROUGH
THE NEXT SEVERAL HOURS TO REFLECT THE LATEST OBS AND TRENDS. THE REST
OF THE FORECAST REMAINS ON TRACK. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 725 AM EDT TUE AUG 13 2013
AVN CONDITIONS THROUGH EAST KENTUCKY WILL REMAIN RATHER POOR DURING
THE REST OF MORNING AS AREAS OF CONVECTION AND PATCHY FOG MOVE
THROUGH. HAVE LIMITED THE THUNDER AND VCTS CHANCES TO THE SOUTHERN
TAF SITES OF LOZ AND SME. ONCE THIS WAVE OF PCPN CLEARS...BY MID
MORNING...CONDITIONS WILL IMPROVE THROUGH THE DAY WITH JUST A SMALL
CHANCE OF A SHOWER OR THUNDERSTORM AND CIGS GENERALLY HOLDING IN THE
VFR RANGE. WILL FORECAST A TOUCH OF FOG DEVELOPING AT LOZ AND SME TAF
SITES TOWARD DAWN WEDNESDAY. WINDS THROUGH THE PERIOD WILL BE LIGHT
AND VARIABLE... OUTSIDE OF ANY STORM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
725 AM EDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 725 AM EDT TUE AUG 13 2013
UPDATED THE NEAR TERM GRIDS TO REFLECT THE BANDED SHOWERS CROSSING
THE SOUTHEAST PARTS OF THE CWA. ALSO ADJUSTED THE T/TD GRIDS THROUGH
THE NEXT SEVERAL HOURS TO REFLECT THE LATEST OBS AND TRENDS. THE REST
OF THE FORECAST REMAINS ON TRACK. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 725 AM EDT TUE AUG 13 2013
AVN CONDITIONS THROUGH EAST KENTUCKY WILL REMAIN RATHER POOR DURING
THE REST OF MORNING AS AREAS OF CONVECTION AND PATCHY FOG MOVE
THROUGH. HAVE LIMITED THE THUNDER AND VCTS CHANCES TO THE SOUTHERN
TAF SITES OF LOZ AND SME. ONCE THIS WAVE OF PCPN CLEARS...BY MID
MORNING...CONDITIONS WILL IMPROVE THROUGH THE DAY WITH JUST A SMALL
CHANCE OF A SHOWER OR THUNDERSTORM AND CIGS GENERALLY HOLDING IN THE
VFR RANGE. WILL FORECAST A TOUCH OF FOG DEVELOPING AT LOZ AND SME TAF
SITES TOWARD DAWN WEDNESDAY. WINDS THROUGH THE PERIOD WILL BE LIGHT
AND VARIABLE... OUTSIDE OF ANY STORM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
635 AM EDT Tue Aug 13 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 600 AM EDT Tue Aug 13 2013
This round of precip seems to be winding down, though these dry
periods have been very quick the past few days. Latest RAP indicates
some potential for another round somewhere over our western border
counties and of course in the still moisture rich environment across
the southeast. Brought back some slight chances to the west through
the morning then push the dry line south as the front gets through.
Speaking of the front, the first one to pass our area is hard to
define, except with a weak pressure trough running from near KCVG
and then through our northern counties. Second front now is over
northern Indiana, with dewpoints the easier find there, readings in
the 50s.
.SHORT TERM (Now through Wednesday)...
Issued at 245 AM EDT Tue Aug 13 2013
A couple of fronts are headed our way today. The first is slower
moving and stretches roughly from Lake Erie right to our northern
row of counties. The second has a more noticeable dewpoint
difference and is located between Central Michigan and southern
Wisconsin. Expect the first front to bring a wind shift into the
Ohio River area in the next few hours, but the main drier air with
the second front will not get here until this afternoon.
With a continued moist airmass in place ahead of the first front, we
are seeing lines of showers/embedded thunder continue to develop
early this morning. Will continue to watch for training of heavier
cells, but that watch should end soon, as that second front brings a
great rest of the work week forecast.
Highs today will depend on who can see the most sunshine. Most
places will stay cloudy, keeping readings around 80. The northern
forecast area has the best chance to break out behind the front, but
north winds should temper the extra sunshine and keep readings in
the lower 80s. Tonight, a steady north wind will keep us from ideal
radiational cooling, but lows should fall into the 50s for most
everyone. Then Wednesday under full sunshine and a north/northeast
wind highs look to rise only to the mid/upper 70s. Dewpoints may
drop into the mid 40s across the north, very low for mid August!
.LONG TERM (Wednesday Night through Monday)...
Issued at 300 AM EDT Tue Aug 13 2013
Upper air pattern will undergo a transition during the extended
period from troughing centered over the eastern Great Lakes (which
has been the prevailing pattern almost all summer) to a more typical
mid-summer pattern in which flat zonal flow retreats well north of
the Canadian border. However, this latter zonal flow won`t really
become established until Monday or Tuesday of next week.
A very dry and unseasonably cool airmass will already be in place
across the Great Lakes and the Lower Ohio Valley by Wednesday
evening. By late Wednesday, high pressure of Canadian origin is
forecast to lie near Chicago, with a ridge axis extending southeast
toward West Virginia. Clear skies and light winds will allow for
almost perfect radiational cooling early Thursday, and some
remarkably cool (for mid-August) overnight lows are expected for
early Thursday morning. Some lows may dip below 50 across some of
our typically colder rural locations!
Expect mostly clear skies with very comfortable temperatures and
humidities through Friday morning as high pressure settles overhead.
Highs both Thursday and Friday will hover not too far from 80. Lows
early Friday morning will reach the mid 50s.
For Saturday and Sunday, surface high pressure will move over New
England, with ridging extending southwest over the Ohio
River. Winds will stay quite light through the weekend, mostly from
an easterly direction. A weak upper level disturbance will slide
south across Missouri late Friday and will establish a weak 500mb
trough across southern Illinois, which will basically stay in
place through Sunday.
Isolated to scattered showers and thunderstorms are expected to our
east over the southern Appalachians on Friday, this convection may
re-develop a bit farther west Saturday and Sunday as light easterly
winds at the surface combine with relatively cool 500mb highs to
bring moderate afternoon and evening instability each day. This
convection will not be as widespread nor produce the heavy downpours
that some locations experienced over this past weekend. They will
also tend to develop during the afternoon and diminish during the
evening hours. Overall expect partly cloudy skies this weekend with
relatively cool highs in the lower to mid 80s with overnight lows in
the 60s. Think that each afternoon, scattered thunderstorm coverage
will be greatest across our southeastern counties and most sparse
across southern Indiana.
&&
.AVIATION (12Z TAF Update)...
Issued at 630 AM EDT Tue Aug 13 2013
Cold fronts still north of the terminals this morning. Thus
low-level moisture pooled ahead of them will keep lower ceilings in
at least for the next few hours. Expect the wind shift to come by
mid morning and help start to scour out these ceilings, in concert
with daytime heating. We may see a shower/storm at KBWG with the
passage around Noon, but then all sites should be VFR with stronger
north winds.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........RJS
Short Term.....RJS
Long Term......JSD
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
605 AM EDT Tue Aug 13 2013
...Forecast Update...
Issued at 600 AM EDT Tue Aug 13 2013
This round of precip seems to be winding down, though these dry
periods have been very quick the past few days. Latest RAP indicates
some potential for another round somewhere over our western border
counties and of course in the still moisture rich environment across
the southeast. Brought back some slight chances to the west through
the morning then push the dry line south as the front gets through.
Speaking of the front, the first one to pass our area is hard to
define, except with a weak pressure trough running from near KCVG
and then through our northern counties. Second front now is over
northern Indiana, with dewpoints the easier find there, readings in
the 50s.
.SHORT TERM (Now through Wednesday)...
Issued at 245 AM EDT Tue Aug 13 2013
A couple of fronts are headed our way today. The first is slower
moving and stretches roughly from Lake Erie right to our northern
row of counties. The second has a more noticeable dewpoint
difference and is located between Central Michigan and southern
Wisconsin. Expect the first front to bring a wind shift into the
Ohio River area in the next few hours, but the main drier air with
the second front will not get here until this afternoon.
With a continued moist airmass in place ahead of the first front, we
are seeing lines of showers/embedded thunder continue to develop
early this morning. Will continue to watch for training of heavier
cells, but that watch should end soon, as that second front brings a
great rest of the work week forecast.
Highs today will depend on who can see the most sunshine. Most
places will stay cloudy, keeping readings around 80. The northern
forecast area has the best chance to break out behind the front, but
north winds should temper the extra sunshine and keep readings in
the lower 80s. Tonight, a steady north wind will keep us from ideal
radiational cooling, but lows should fall into the 50s for most
everyone. Then Wednesday under full sunshine and a north/northeast
wind highs look to rise only to the mid/upper 70s. Dewpoints may
drop into the mid 40s across the north, very low for mid August!
.LONG TERM (Wednesday Night through Monday)...
Issued at 300 AM EDT Tue Aug 13 2013
Upper air pattern will undergo a transition during the extended
period from troughing centered over the eastern Great Lakes (which
has been the prevailing pattern almost all summer) to a more typical
mid-summer pattern in which flat zonal flow retreats well north of
the Canadian border. However, this latter zonal flow won`t really
become established until Monday or Tuesday of next week.
A very dry and unseasonably cool airmass will already be in place
across the Great Lakes and the Lower Ohio Valley by Wednesday
evening. By late Wednesday, high pressure of Canadian origin is
forecast to lie near Chicago, with a ridge axis extending southeast
toward West Virginia. Clear skies and light winds will allow for
almost perfect radiational cooling early Thursday, and some
remarkably cool (for mid-August) overnight lows are expected for
early Thursday morning. Some lows may dip below 50 across some of
our typically colder rural locations!
Expect mostly clear skies with very comfortable temperatures and
humidities through Friday morning as high pressure settles overhead.
Highs both Thursday and Friday will hover not too far from 80. Lows
early Friday morning will reach the mid 50s.
For Saturday and Sunday, surface high pressure will move over New
England, with ridging extending southwest over the Ohio
River. Winds will stay quite light through the weekend, mostly from
an easterly direction. A weak upper level disturbance will slide
south across Missouri late Friday and will establish a weak 500mb
trough across southern Illinois, which will basically stay in
place through Sunday.
Isolated to scattered showers and thunderstorms are expected to our
east over the southern Appalachians on Friday, this convection may
re-develop a bit farther west Saturday and Sunday as light easterly
winds at the surface combine with relatively cool 500mb highs to
bring moderate afternoon and evening instability each day. This
convection will not be as widespread nor produce the heavy downpours
that some locations experienced over this past weekend. They will
also tend to develop during the afternoon and diminish during the
evening hours. Overall expect partly cloudy skies this weekend with
relatively cool highs in the lower to mid 80s with overnight lows in
the 60s. Think that each afternoon, scattered thunderstorm coverage
will be greatest across our southeastern counties and most sparse
across southern Indiana.
&&
.AVIATION (06Z TAF Update)...
Issued at 1205 AM EDT Tue Aug 13 2013
Did an early round of updates to the TAFs as HRRR is indicating some
low cloud development in the wake of last night`s rains. KHNB is
coming in with these low clouds and think they will invade points
farther east as the night goes on. For now have gone with low-end
MVFR cigs, with worse conditions at KLEX by daybreak. Would not be
surprised to see some lower ceilings, but will introduce into the
TAFs for now and see how trends go the rest of the early morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........RJS
Short Term.....RJS
Long Term......JSD
Aviation.......RJS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
450 AM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AVN CONDITIONS THROUGH EAST KENTUCKY WILL REMAIN RATHER POOR DURING
THE REST OF THE NIGHT AS AREAS OF CONVECTION AND PATCHY FOG MOVE
THROUGH. HAVE LIMITED THE THUNDER AND VCTS CHANCES TO THE SOUTHERN
TAF SITES OF LOZ AND SME. ONCE THIS WAVE OF PCPN CLEARS LATE THIS
NIGHT WOULD ALSO EXPECT LOWER VIS FROM FOG...BUT PROBABLY NOT AS
DENSE AS WE SAW LAST NIGHT AT JKL. CONDITIONS WILL THEN IMPROVE
THROUGH THE DAY TUESDAY WITH JUST A SMALL CHANCE OF A SHOWER OR
THUNDERSTORM AND CIGS GENERALLY HOLDING IN THE VFR RANGE. WINDS
THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE...OUTSIDE OF ANY
THUNDERSTORM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
304 AM EDT Tue Aug 13 2013
.SHORT TERM (Now through Wednesday)...
Issued at 245 AM EDT Tue Aug 13 2013
A couple of fronts are headed our way today. The first is slower
moving and stretches roughly from Lake Erie right to our northern
row of counties. The second has a more noticeable dewpoint
difference and is located between Central Michigan and southern
Wisconsin. Expect the first front to bring a wind shift into the
Ohio River area in the next few hours, but the main drier air with
the second front will not get here until this afternoon.
With a continued moist airmass in place ahead of the first front, we
are seeing lines of showers/embedded thunder continue to develop
early this morning. Will continue to watch for training of heavier
cells, but that watch should end soon, as that second front brings a
great rest of the work week forecast.
Highs today will depend on who can see the most sunshine. Most
places will stay cloudy, keeping readings around 80. The northern
forecast area has the best chance to break out behind the front, but
north winds should temper the extra sunshine and keep readings in
the lower 80s. Tonight, a steady north wind will keep us from ideal
radiational cooling, but lows should fall into the 50s for most
everyone. Then Wednesday under full sunshine and a north/northeast
wind highs look to rise only to the mid/upper 70s. Dewpoints may
drop into the mid 40s across the north, very low for mid August!
.LONG TERM (Wednesday Night through Monday)...
Issued at 300 AM EDT Tue Aug 13 2013
Upper air pattern will undergo a transition during the extended
period from troughing centered over the eastern Great Lakes (which
has been the prevailing pattern almost all summer) to a more typical
mid-summer pattern in which flat zonal flow retreats well north of
the Canadian border. However, this latter zonal flow won`t really
become established until Monday or Tuesday of next week.
A very dry and unseasonably cool airmass will already be in place
across the Great Lakes and the Lower Ohio Valley by Wednesday
evening. By late Wednesday, high pressure of Canadian origin is
forecast to lie near Chicago, with a ridge axis extending southeast
toward West Virginia. Clear skies and light winds will allow for
almost perfect radiational cooling early Thursday, and some
remarkably cool (for mid-August) overnight lows are expected for
early Thursday morning. Some lows may dip below 50 across some of our
typically colder rural locations!
Expect mostly clear skies with very comfortable temperatures and
humidities through Friday morning as high pressure settles overhead.
Highs both Thursday and Friday will hover not too far from 80. Lows
early Friday morning will reach the mid 50s.
For Saturday and Sunday, surface high pressure will move over New
England, with ridging extending southwest over the Ohio
River. Winds will stay quite light through the weekend, mostly from
an easterly direction. A weak upper level disturbance will slide
south across Missouri late Friday and will establish a weak 500mb
trough across southern Illinois, which will basically stay in
place through Sunday.
Isolated to scattered showers and thunderstorms are expected to our
east over the southern Appalachians on Friday, this convection may
re-develop a bit farther west Saturday and Sunday as light easterly
winds at the surface combine with relatively cool 500mb highs to
bring moderate afternoon and evening instability each day. This
convection will not be as widespread nor produce the heavy downpours
that some locations experienced over this past weekend. They will
also tend to develop during the afternoon and diminish during the
evening hours. Overall expect partly cloudy skies this weekend with
relatively cool highs in the lower to mid 80s with overnight lows in
the 60s. Think that each afternoon, scattered thunderstorm coverage
will be greatest across our southeastern counties and most sparse
across southern Indiana.
&&
.AVIATION (06Z TAF Update)...
Issued at 1205 AM EDT Tue Aug 13 2013
Did an early round of updates to the TAFs as HRRR is indicating some
low cloud development in the wake of last night`s rains. KHNB is
coming in with these low clouds and think they will invade points
farther east as the night goes on. For now have gone with low-end
MVFR cigs, with worse conditions at KLEX by daybreak. Would not be
surprised to see some lower ceilings, but will introduce into the
TAFs for now and see how trends go the rest of the early morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........RJS
Long Term.........JSD
Aviation..........RJS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1215 AM CDT Tue Aug 13 2013
.UPDATE...
Updated aviation discussion only.
&&
.SHORT TERM...(This Evening through Tuesday Night)
ISSUED AT 1250 PM CDT MON AUG 12 2013
It looks like the blended model approach is too slow. It lingers
pops well after fropa into/thru Tuesday. We went with the HRRR and
Nam`s more meso type solutions, which had higher resolution and
initiated well. It has higher pops but departs them more quickly
with fropa and with the aforementioned finer resolution. It models
the initial environment well, so we at least are hoping for a nice
0-6 hr init with a transition toward the Nam in the overall pop
modeling thru Tuesday. Alot will be told here with how the
remainder of the pm/into the early evening goes. Should see fairly
active/high concentration convection to continue breaking out in
moist/unstable air ahead of incoming front/energy this pm-
evening...to sweep southward with time/with perhaps additional
development along main front as well as outflow boundaries thru
the overnight hours. Meso models take the front thru tonight and
start to usher in the drier air at the lower levels late tonight-
early tmrw, which should preclude pop mention. We`ll watch closely
and also see about collab as to whether to remove pop altogether or
leave lingering Tuesday pop. Certainly by Tue evening-overnight all
models are in agreement that the drier dew points are working thru
the column and we poise for the nice pleasant cooler/drier air to
take root from mid week on.
.LONG TERM /Wednesday through Monday/...
ISSUED AT 215 PM CDT MON AUG 12 2013
Unusually high amplitude flow pattern for the middle of August will
continue...with a large ridge in the west and a deep trough in the
Mississippi and Ohio Valley regions. The trough is forecast to
weaken late in the period /Monday/...which will result in some
semblance of a typical August pattern.
As far as the daily details...
An unseasonably strong /1023 mb/ surface high will progress slowly
east across the Great Lakes and upper Midwest Wednesday through
Thursday. This high will funnel a cool and dry air mass
southward...with 850 mb temps ranging from 10 to 12 for much of the
period. These 850 mb temps support highs only in the upper 70s with
full sun. Overnight lows will be in the lower to mid 50s. Generally
followed the cooler NAM mos for low temps...though the difference
between NAM and GFS mos is negligible in some places. It should be
noted that 850 mb temp anomalies Wed/Thu will be 2 to 3 standard
deviations below normal. The air mass will also be very dry. Model
soundings suggest nothing more than a few pancake cumulus clouds
each afternoon.
On Friday and Friday night...an inverted surface trough will
retrograde westward across the Tennessee Valley as a 500 mb
shortwave digs southeast into the Mississippi Valley. It will take a
while for the atmosphere to moisten up...so only the far southeast
counties /KHOP area/ nearest the surface trough are at risk of any
precip.
Saturday through Sunday...the upper trough will be nearly overhead.
Some guidance indicates the trough will close off into an upper low
over our region. At low levels...the inverted trough will take up
residence near or just south of our region. Dew point pooling along
the surface trough will bring dew points up through the 60s. Precip
water values are forecast to climb steadily to between 1.5 and 2
inches by Sunday /GFS model/. The models are considerably more
unstable than they were yesterday...so will add mention of thunder
for the weekend. Pops will be in the chance category in most areas
for Sunday. Most of the precip should be diurnally driven
convection.
On Monday...the upper trough is forecast to weaken and/or lift
northeast. The surface trough will dissipate...leaving only a
weakly cyclonic east to southeast flow. Precip chances will begin to
diminish from the west. Temps and humidity will gradually approach
climo.
&&
.AVIATION...
ISSUED AT 1215 AM CDT TUE AUG 13 2013
Winds across the area will be rather light and generally from the
west or sw shortly after midnight, until a cold front passes through
the area late in the night, which will turn winds to the nw.
There is a small chance of pcpn ahead of the front, but the
probability of occurrence was too low to include in TAFs. Winds just
off the sfc should be enough to preclude other than brief MVFR fog.
Instead, there may be some scattered low clouds associated with the
front. VFR conditions can be expected after sunrise, with a nwrly
breeze up to about 10 knots.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
Short term...DH
Long term...MY
Aviation...DB
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1209 AM EDT Tue Aug 13 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1135 PM EDT Mon Aug 12 2013
Main area of precipitation almost is out of the area, though heavy
rains continue in the Lake Cumberland region. Once that system
exits, we have some signs on radar of a few more bands that could
develop overnight, with the main front still to our north. Thus have
tweaked pops a little as well as matched up obs with ongoing
conditions. Also added in some patchy dense fog as we may get some
denser low clouds to drop in spots overnight. KHNB is reporting a
200 foot overcast this hour.
Issued at 1000 PM EDT Mon Aug 12 2013
Large cluster of convection continues to work eastward across the
state this evening. Torrential rainfall and quite a bit of
lightning have been the main weather threats with this activity.
Activity will continue to work eastward across the Lake Cumberland
region over the next few hours producing torrential rainfall and
lightning. Further norther, a break in the precipitation is
expected. However, some additional convection may accompany the
surface cold front as it continues to press southward through
northern Indiana and central Illinois. This will result in a
continued threat of a shower or storm into the overnight period,
with most locations seeing much drier weather toward dawn Tuesday.
Update issued at 602 PM EDT Mon Aug 12 2013
Currently watching two bands of convection work their way across the
Commonwealth this evening. The first batch is moving just south of
the Louisville metro area. This activity is becoming more outflow
dominated while the line surges eastward. Based on current radar
trajectories, this activity looks to pass just south of this
morning`s heavy rainfall axis which extended from near Spencer Co KY
to the Clark/Madison county border region. Additional convection is
developing over the northern Bluegrass where the atmosphere has had
time to recover this afternoon. Any of these storms will contain a
ton of lightning and torrential rainfall. The heavy rainfall and
flooding will be the major weather threats with this activity.
Second line of convection is organizing out across western
Kentucky...along a line from near OWB to just south of PAH. This
activity will head east and affect our south-central areas this
evening. Quite a bit of lightning and heavy rainfall will be the
threats here. However, hydro issues may be a bit more isolated as
rainfall has not been that much down there over the last 6-8 hours.
Nonetheless, any heavy rainfall will be capable of producing quick
rises on creeks, streams, and poor drainage areas.
.SHORT TERM (Now through Tuesday Night)...
Issued at 315 PM EDT Mon Aug 12 2013
The synoptic pattern this afternoon features zonal flow aloft,
which will transition to more of an eastern trough/western ridge
pattern through the period. A shortwave trough and associated
surface front will slide through the Ohio Valley late this afternoon
through the overnight hours, continuing to bring showers and
thunderstorms to the region.
Quite a complex forecast for the rest of today into tonight, as
several forcing mechanisms focus into a moist airmass that has
advected into the region. In the near term, a strong wave of
isentropic ascent will continue to lift northeast through the
northern Bluegrass. After that, there will likely be a brief lull
in the more widespread activity. However, with sunshine beginning
to peak out, renewed thunderstorm development will likely occur
which is already underway across southern Indiana and north-central
KY. Think this activity will remain scattered for the next few
hours, before the main forcing arrives this evening and increases
coverage. A strong shortwave trough, evident on water vapor imagery
across central MO, will quickly slide into the Ohio Valley. It is
just now beginning to interact with the best instability axis,
likely explaining the thunderstorm development recently occurring
across southeast MO. This activity will likely expand in coverage
through the next few hours as it heads across western IL and KY.
However, by the time it reaches the western CWA, it will likely be
in a weakening phase as we will not be quite as unstable.
Nonetheless, still think coverage will be about 60% as it enters the
west, possibly fading in coverage through the late evening into the
first part of the overnight hours as instability wanes. Heavy
rainfall will continue to be the main threat, although an isolated
severe storm will be possible given the better kinematics (effective
shear about 40 knots currently in southern IN/northern KY). This may
support some multicells or even a transient supercell structure
which may be capable of some strong wind gusts or perhaps even some
small hail.
Overnight, another wave looks as if it will push northeast along the
surface front, which may enhance the precipitation across southern
KY around midnight as a weak low-level jet develops. This
convection will push east by the late morning hours. Some
additional development is possible across mainly southern KY through
early Tuesday afternoon as another secondary front drops through the
region, but think any of this activity will remain rather isolated.
Canadian high pressure will build firmly into the region by Tuesday
night. After a muggy night tonight, cooler and drier air will push
in tomorrow, as highs fall into the low and mid 80s with much lower
humidity values. Have dropped temperatures a bit Tuesday night as
the Canadian high settles in. Lows will be quite chilly compared to
recent days as they bottom out in the mid 50s to lower 60s.
.LONG TERM (Wednesday through Monday)...
Issued at 315 AM EDT Mon Aug 12 2013
Surface High Pressure dominates the Ohio Valley for the majority of
the extended period. By Friday night, as the High starts to exit to
the east, southerly low level flow begins to return, and along with
it, a returning chance for precipitation - at least for the southern
counties along the Tennessee border. The GFS and Euro are in
agreement on this trend, but there are differences in the strength
of the 500 mb flow, with the GFS generating a closed low and
introducing showers as early as Friday evening, while the ECMWF
keeps the 500 mb flow an open wave, and brings the convection in on
Saturday. Both keep then spread the chance for showers and
thunderstorms across the CWA for Sunday and Monday.
Given that the main precip chances are in days 6 and 7, and that the
southerly surface flow appears more southeasterly in both models,
this looks to be a borderline shower/thunderstorm event, and
adjustments will no doubt made in intervening forecasts. For now,
the most certain statement that can be made is that the best weather
of the extended will be during the second half of this work week,
with clear skies, dry air and below normal temperatures ushering in
the start of the Kentucky State Fair.
High temperatures through the period will be in the upper 70s to low
80s. Lows Thursday and Friday mornings will be in the 50s across
the area, before moderating into the lower to mid 60s over the
weekend and Monday morning. Both the highs and lows are at or below
seasonal norms for mid August.
&&
.AVIATION (06Z TAF Update)...
Issued at 1205 AM EDT Tue Aug 13 2013
Did an early round of updates to the TAFs as HRRR is indicating some
low cloud development in the wake of last night`s rains. KHNB is
coming in with these low clouds and think they will invade points
farther east as the night goes on. For now have gone with low-end
MVFR cigs, with worse conditions at KLEX by daybreak. Would not be
surprised to see some lower ceilings, but will introduce into the
TAFs for now and see how trends go the rest of the early morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Updates........MJ/RJS
Short Term.....KJD
Long Term......JBS
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
410 AM EDT TUE AUG 13 2013
.SYNOPSIS...
AFTER A COLD FRONT BRINGS SHOWERS TODAY...COOL AND DRY CONDITIONS
CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
TWO MAIN AREAS OF RAIN CONTINUE TO PUSH TO THE EAST. NORTHERNMOST
TIER OF COUNTIES WILL HAVE SOME STRONG STORMS OVER THE NEXT FEW
HOURS...WHILE HEAVY RAIN WILL CONTINUE SOUTH OF THE MASON-DIXON
LINE. ALTHOUGH RAIN RATES ACROSS THE SOUTH HAVE DIMINISHED
CONSIDERABLY FROM WHAT THEY WERE AT MIDNIGHT...WILL CONTINUE THE
FLASH FLOOD WATCH UNTIL THE RAIN CLEARS THE REGION. IN BETWEEN THESE
TWO AREAS OF RAIN...ISOLATED SHOWERS/STORMS HAVE STARTED TO DEVELOP.
MAJORITY OF RAIN WILL MOVE OFF TO THE EAST BY MID MORNING.
HOWEVER...COLD FRONT WILL BRING SIGNIFICANTLY COLDER TEMPERATURES AT
850MB. SFC-850 TEMPERATURE DIFFERENCES WILL BE LARGE ENOUGH FOR SOME
LAKE EFFECT CLOUDS AND EVEN ISOLATED SHOWERS TO DEVELOP ALONG THE
COLD FRONT. WHILE MESOSCALE MODELS KEEP THE FORECAST DRY...HI-RES
MODELS INCLUDING THE HRRR SHOW THESE SHOWERS TO BEGIN BY EARLY
AFTERNOON. HAVE KEPT ISOLATED SHOWERS IN THE FORECAST THROUGH MOST
OF THE DAY TO ACCOUNT FOR THIS PRECIPITATION. WENT WITH LAMP
GUIDANCE FOR TEMPERATURES...WHICH YIELDS HIGHS ABOUT 10 DEGREES
BELOW NORMAL.
WHILE LAKE EFFECT CLOUD COVER WILL CONTINUE TONIGHT...THINK THAT
SHOWERS WILL NOT CONTINUE. BEHIND THE COLD FRONT...LOWS WILL BE
10-15 DEGREES COLDER THAN LAST NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
EXPECT QUIET WEATHER THROUGH THIS STRETCH WITH HIGH PRESSURE ACROSS
THE GREAT LAKES. HAVE LOWERED TEMPERATURES A COUPLE DEGREES
WEDNESDAY AND WEDNESDAY NIGHT. THIS NOW KEEPS LOCATIONS NORTH OF
PITTSBURGH IN THE 60S FOR HIGHS...AND DROPS MANY LOCATIONS TO THE
40S WEDNESDAY NIGHT. TEMPERATURES THURS/THURS NIGHT WILL BE ABOUT 5
DEGREES HIGHER THAN THE PREVIOUS DAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
WHILE HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER FRIDAY AND
FRIDAY NIGHT...TROPICAL MOISTURE WILL START TO MOVE IN FROM THE
SOUTH. THIS WILL RESULT IN INCREASING CHANCES FOR SHOWERS AND
STORMS. MODERATING TEMPERATURES SHOULD BE NEAR NORMAL BY SATURDAY.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
CONDITIONS OVERNIGHT SHOULD DETERIORATE WITH SHOWERS AND LOW CLOUDS
MOVING THROUGH. EXPECT MVFR. COULD SEE A BRF PD OF IFR AT PORTS N
AND W OF PIT. CLD FNT PASSES 10-14Z. MVFR CIGS SHOULD LINGER THROUGH
MOST OF THE MORNING AND INTO EARLY AFTERNOON. IT IS LIKELY THAT
EASTERN AND NORTHERN PORTS WILL HOLD ON TO MVFR CLOUDS THE LONGEST.
CONDITIONS WILL IMPROVE TO VFR CU/STRATOCU...FROM WEST TO EAST..
DURING THE AFTN. EXP A WSHFT FM SW TO NW AFT FROPA WITH SOME SPEEDS
12G20KT TUE AFTN.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
VFR CONDS EXPD THRU THE PD WITH BLDG HIGH PRES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH UNTIL 11 AM EDT THIS MORNING FOR MDZ001.
OH...NONE.
PA...NONE.
WV...FLASH FLOOD WATCH UNTIL 11 AM EDT THIS MORNING FOR WVZ012-
021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
148 PM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.UPDATE...
ISSUED AT 147 PM EDT TUE AUG 13 2013
EVERYTHING ON TRACK FOR THE MOMENT. EMBEDDED SHORT WAVE TROUGH
SEEN IN WATER VAPOR IMAGERY CENTERED JUST NORTHEAST OF SAULT SAINT
MARIE...ROTATING SOUTHWARD WITH SOME COLDER CLOUD TOPS SHOWING UP
ON ENHANCED IR SATELLITE (INDICATIVE OF SOME SYNOPTIC UPWARD
FORCING). SHORT WAVE TROUGH...ALONG WITH ASSOCIATED BETTER MOISTURE
WILL BE DROPPING THROUGH THE REGION THROUGH THE COURSE OF THE
AFTERNOON. MAY ALREADY BE SEEING THE EFFECTS OF INCREASING FORCING
WITH SPOTTY SHOWERS NOW SHOWING UP OVER PARTS OF NRN LOWER
MICHIGAN. SO...BEST CHANCES FOR SHOWERS WILL BE OVER THE NEXT
SEVERAL HOURS INTO EARLY EVENING...WITH THE COMBINED EFFECTS OF
SYNOPTIC FORCING AND LAKE/LAND HEATING INDUCED INSTABILITY.
UPDATE ISSUED AT 1034 AM EDT TUE AUG 13 2013
COLD ADVECTION STILL UNDERWAY ACROSS THE GREAT LAKES ON SOMEWHAT
GUSTY N/NW WINDS...AHEAD OF HIGH PRESSURE BUILDING INTO THE REGION
FROM SOUTH-CENTRAL CANADA. 12Z APX SOUNDING REVEALING AN 850 MB
TEMP OF +4C...RATHER COLD FOR THIS TIME OF YEAR AND FORECAST TO
BOTTOM OUT AROUND +3C TO +4C THIS AFTERNOON. PLENTY COLD ENOUGH
FOR LAKE CONVECTION...AND SURE ENOUGH...LOTS OF TRUE LAKE BANDS
HAVE DEVELOPED ON THE LAKES...PARTICULARLY ON LAKES MICHIGAN AND
HURON.
WITH HEATING...HYBRID LAKE AND LAND HEATING INDUCED STCU WILL
OVERSPREAD THE CWA AS WE GO THROUGH THE REST OF THE MORNING...A
PROCESS ALREADY UNDERWAY PER SATELLITE TRENDS IN THE LAST HOUR OR
SO. DEEP ENOUGH CONVECTION THAT A FEW SHOWERS APPEAR LIKELY THIS
AFTERNOON PARTICULARLY DOWNWIND OF THE LAKES WITH THE MOISTURE
FEED. IN FACT...APX RADAR ALREADY PICKING UP A FEW RETURNS OFF OF
GRAND TRAVERSE BAY. WILL MAKE SOME COSMETIC TWEAKS TO THE GRIDS
FOR SCATTERED SHOWERS AND HAVE INCREASED CLOUD COVER THROUGH THE
AFTERNOON. OTHERWISE...A DOWNRIGHT COOL DAY AHEAD WITH TEMPS A
SOLID 15 DEGREES BELOW NORMAL.
UPDATE ISSUED AT 657 AM EDT TUE AUG 13 2013
INCREASED WIND GUSTS IN A FEW SPOTS...MAINLY OVER THE GREAT
LAKES...PER LATEST OBS AND INCREASING INSTABILITY. LOW LEVEL
MOISTURE EXPECTED TO DEVELOP INTO A PERIOD OF MOSTLY CLOUDY
SKIES...OF WHICH DID MAKE A CHANGE TO EXTEND THIS CLOUDIEST TIME
PERIOD. OTHERWISE...FORECAST LOOKING GOOD.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 147 PM EDT TUE AUG 13 2013
LOTS OF CLOUD COVER DRAPED ACROSS NRN LOWER MICHIGAN THIS
AFTERNOON THANKS TO DAYTIME HEATING AND COLD POOL ALOFT DROPPING
DOWN THROUGH THE REGION. SPOTTY SHOWERS SHOWING UP ACROSS THE TIP
OF THE MITT NEAR KPLN AND ADDITIONAL SHOWER DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON AS SHORT WAVE DROPS DOWN THROUGH THE
REGION. CIGS WILL REMAIN LARGELY VFR...ALTHOUGH BRIEF BOUTS OF
MVFR CIGS ARE POSSIBLE INTO THE EARLY EVENING. GUSTY NORTH WINDS
WILL PERSIST WITH HIGHEST GUSTS REACHING THE LOW 20 KNOT RANGE.
TONIGHT...WILL THIN OUT QUITE A BIT OF THE CLOUD COVER WITH LOSS
OF HEATING...ALTHOUGH TVC/APN MAY RETAIN SCT-BKN CONDITIONS WITH
FLOW OFF THE LAKES. GUSTINESS SUBSIDES BUT WE WILL MAINTAIN A
SUSTAINED 5 TO 10 KNOT NORTH-NORTHWEST WIND THROUGH THE NIGHT.
WINDS TURN MORE NORTHWESTWARD ON WEDNESDAY BUT WITH A BIT LESS
GUSTINESS. SCT-BKN VFR CIGS AGAIN ON WEDNESDAY PARTICULARLY AT
APN.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...BA
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...BA
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 PM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT TUE AUG 13 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
QUEBEC INTO NRN ONTARIO RESULTING IN CYCLONIC WNW FLOW THROUGH THE
NRN GREAT LAKES. LITTLE MORE THAN PATCHY MID CLOUDS WERE ASSOCIATED
WITH A SHORTWAVE TROUGH MOVING THROUGH WRN LAKE SUPERIOR WHILE MORE
EXTENSIVE CLOUDS AND A FEW SPRINKLES WERE OBSERVED WITH ANOTHER
SHRTWV JUST UPSTREAM...TO THE N OF LAKE SUPERIOR. AT THE SFC...HIGH
PRES OVER MANITOBA INTO NW MN WAS BUILDING INTO THE WRN LAKES WITH
NRLY FLOW PREVAILING ACROSS LAKE SUPERIOR INTO UPPER MICHIGAN.
TODAY...AS THE SHRTWV FROM N OF THE LAKE AND A POCKET OF LOWER 700 MB
TEMPS AROUND -6C...DROPS THROUGH THE CWA...MODELS SUGGEST THAT SOME
ISOLD SHOWERS WILL BE POSSIBLE FROM LATE THIS MORNING INTO THE EARLY
AFTERNOON...MAINLY THROUGH W CNTRL UPPER MI. IN ITS WAKE...SUBSIDENCE
AND DRYING WILL BUILD QUICKLY INTO THE AREA...ENDING ANY PCPN BY MID
TO LATE AFTERNOON.
TONIGHT...WITH CLEARING SKIES AND LIGHT WINDS AS THE HIGH BUILD INTO
THE REGION...FAVORABLE RADIATIONAL COOLING CONDITIONS IN THE DRY
AIRMASS(PWAT TO AROUND 0.50 INCH OR 50 PCT OR NORMAL) WILL ALLOW
TEMPERATURES TO DROP TOWARD THE LOWER END OF GUIDANCE....INTO THE
MID TO UPPER 30S INLAND WEST. THE TYPICAL COLDER LOCATIONS FROM
CHAMPION AND AMASA TO WATERSMEET...KENTON AND WATERSMEET COULD SEE
SOME PATCHY FROST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 432 AM EDT TUE AUG 13 2013
THE VERY COOL MORNING TEMPS WILL QUICKLY RISE INTO THE UPPER 60S TO
MID 70S WEDNESDAY AS THE SFC HIGH OVERHEAD CONTINUES TO SLOWLY SINK
TO OUR SSE. A SLOW WARMING TREND WILL BEGIN WEDNESDAY NIGHT...WITH
THE SFC HIGH LINGERING ACROSS THE OHIO VALLEY AND NEW ENGLAND STATES
THROUGH AT LEAST THE START OF THE NEXT WORK WEEK.
THURSDAY WILL SEE A RETURN OF NEAR NORMAL HIGH TEMPS...IN THE
70S...AS 850MB TEMPS FINALLY RISE INTO THE DOUBLE DIGITS AND...STAY
THERE FOR THE REMAINDER OF THE FCST PERIOD.
THERE WILL BE ONLY FEW SYSTEMS OF NOTE OVER THE WEEK...WITH NW FLOW
ALOFT REMAINING IN PLACE THROUGH THE END OF THE WORK WEEK. THE MAIN
500MB LOW WILL BE SPINNING AROUND AND NEAR QUEBEC THROUGH THURSDAY
BEFORE EJECTING NE IN THE MAIN FLOW AROUND THE STRONGER POLAR LOW. A
SERIES OF SHORTWAVES WILL ATTEMPT TO ROUND THE HIGH AMPLITUDE RIDGE
OVER MUCH OF THE WESTERN STATES EARLY TO MID WEEK...
SEEING A SFC LOW TRACKING FROM S ALBERT AND SASKATCHEWAN ON FRIDAY
TO S CENTRAL CANADA OVER THE WEEKEND. THE 12/12Z ECMWF IS MUCH
QUICKER TO PUSH THE SFC LOW ACROSS HUDSON BAY OVER THE WEEKEND.
THERE ARE SIGNIFICANT ENOUGH TIMING DIFFERENCES BETWEEN THE
AVAILABLE GUIDANCE TO KEEP ONLY LIGHT CHANCE POPS IN THE FCST AS
WARM BUT MAINLY DRY AIR PUSHES IN ON SW WINDS AT THE SFC SATURDAY
THROUGH THE END OF THIS FCST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 127 PM EDT TUE AUG 13 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT ALL TAF
SITES...EXCEPT REALLY EARLY THIS AFTERNOON AT SAW. INSTABILITY SC
WITH A DISTURBANCE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT TUE AUG 13 2013
NRLY WINDS OF 15 TO 20 KNOTS OVER THE ERN PORTIONF OF LAKE SUPERIOR
WILL DIMINISH TONIGHT AS HIGH PRES BUILDS INTO THE REGION. AS THE
HIGH SINKS TO THE SOUTH WED INTO WED NIGHT WRLY WINDS OF 15 TO 20
KNOTS ARE ALSO EXPECTED OVER CNTRL AND ERN LAKE SUPERIOR.
OTHERWISE...WINDS AOB 15 KNOTS WILL PREVAIL INTO SATURDAY.
&&
.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 GAYLORD MI
1034 AM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.UPDATE...
ISSUED AT 1034 AM EDT TUE AUG 13 2013
COLD ADVECTION STILL UNDERWAY ACROSS THE GREAT LAKES ON SOMEWHAT
GUSTY N/NW WINDS...AHEAD OF HIGH PRESSURE BUILDING INTO THE REGION
FROM SOUTH-CENTRAL CANADA. 12Z APX SOUNDING REVEALING AN 850 MB
TEMP OF +4C...RATHER COLD FOR THIS TIME OF YEAR AND FORECAST TO
BOTTOM OUT AROUND +3C TO +4C THIS AFTERNOON. PLENTY COLD ENOUGH
FOR LAKE CONVECTION...AND SURE ENOUGH...LOTS OF TRUE LAKE BANDS
HAVE DEVELOPED ON THE LAKES...PARTICULARLY ON LAKES MICHIGAN AND
HURON.
WITH HEATING...HYBRID LAKE AND LAND HEATING INDUCED STCU WILL
OVERSPREAD THE CWA AS WE GO THROUGH THE REST OF THE MORNING...A
PROCESS ALREADY UNDERWAY PER SATELLITE TRENDS IN THE LAST HOUR OR
SO. DEEP ENOUGH CONVECTION THAT A FEW SHOWERS APPEAR LIKELY THIS
AFTERNOON PARTICULARLY DOWNWIND OF THE LAKES WITH THE MOISTURE
FEED. IN FACT...APX RADAR ALREADY PICKING UP A FEW RETURNS OFF OF
GRAND TRAVERSE BAY. WILL MAKE SOME COSMETIC TWEAKS TO THE GRIDS
FOR SCATTERED SHOWERS AND HAVE INCREASED CLOUD COVER THROUGH THE
AFTERNOON. OTHERWISE...A DOWNRIGHT COOL DAY AHEAD WITH TEMPS A
SOLID 15 DEGREES BELOW NORMAL.
UPDATE ISSUED AT 657 AM EDT TUE AUG 13 2013
INCREASED WIND GUSTS IN A FEW SPOTS...MAINLY OVER THE GREAT
LAKES...PER LATEST OBS AND INCREASING INSTABILITY. LOW LEVEL
MOISTURE EXPECTED TO DEVELOP INTO A PERIOD OF MOSTLY CLOUDY
SKIES...OF WHICH DID MAKE A CHANGE TO EXTEND THIS CLOUDIEST TIME
PERIOD. OTHERWISE...FORECAST LOOKING GOOD.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 657 AM EDT TUE AUG 13 2013
COLD ADVECTION BEHIND COLD FRONT LAST NIGHT HAS RESULTED IN
POCKETS OF MVFR CIGS. THIS SHOULD BE MORE PREVALENT OVER THE NEXT
FEW HOURS WITH SUNUP AND FCST SOUNDINGS SHOWING POTENTIAL TRAPPING
INVERSION. ONGOING TAFS ARE REALLY HARD TO ARGUE...AS THINGS ARE
QUITE TEMPORARY RIGHT NOW ON THE MVFR FRONT. MORE PREVAILING
THROUGH EARLY AFTERNOON...WHICH IS WHAT THE TAFS PORTRAY. DRYING
THROUGH THE DAY AND LOSS OF SUN WILL LEAD TO PREVAILING VFR
CONDITIONS...ALTHOUGH MOISTURE AND INSTABILITY OFF THE LAKE MAY
TRY AND KEEP CLOUDS IN LONGER/REDEVELOP...ESPECIALLY OVERNIGHT.
GUSTY TODAY ALL AREAS...ESPECIALLY ALONG THE LAKESHORES. GUSTS UP
TO 25 KNOTS OUT OF THE NW.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...BA
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
737 AM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT TUE AUG 13 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
QUEBEC INTO NRN ONTARIO RESULTING IN CYCLONIC WNW FLOW THROUGH THE
NRN GREAT LAKES. LITTLE MORE THAN PATCHY MID CLOUDS WERE ASSOCIATED
WITH A SHORTWAVE TROUGH MOVING THROUGH WRN LAKE SUPERIOR WHILE MORE
EXTENSIVE CLOUDS AND A FEW SPRINKLES WERE OBSERVED WITH ANOTHER
SHRTWV JUST UPSTREAM...TO THE N OF LAKE SUPERIOR. AT THE SFC...HIGH
PRES OVER MANITOBA INTO NW MN WAS BUILDING INTO THE WRN LAKES WITH
NRLY FLOW PREVAILING ACROSS LAKE SUPERIOR INTO UPPER MICHIGAN.
TODAY...AS THE SHRTWV FROM N OF THE LAKE AND A POCKET OF LOWER 700 MB
TEMPS AROUND -6C...DROPS THROUGH THE CWA...MODELS SUGGEST THAT SOME
ISOLD SHOWERS WILL BE POSSIBLE FROM LATE THIS MORNING INTO THE EARLY
AFTERNOON...MAINLY THROUGH W CNTRL UPPER MI. IN ITS WAKE...SUBSIDENCE
AND DRYING WILL BUILD QUICKLY INTO THE AREA...ENDING ANY PCPN BY MID
TO LATE AFTERNOON.
TONIGHT...WITH CLEARING SKIES AND LIGHT WINDS AS THE HIGH BUILD INTO
THE REGION...FAVORABLE RADIATIONAL COOLING CONDITIONS IN THE DRY
AIRMASS(PWAT TO AROUND 0.50 INCH OR 50 PCT OR NORMAL) WILL ALLOW
TEMPERATURES TO DROP TOWARD THE LOWER END OF GUIDANCE....INTO THE
MID TO UPPER 30S INLAND WEST. THE TYPICAL COLDER LOCATIONS FROM
CHAMPION AND AMASA TO WATERSMEET...KENTON AND WATERSMEET COULD SEE
SOME PATCHY FROST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 432 AM EDT TUE AUG 13 2013
THE VERY COOL MORNING TEMPS WILL QUICKLY RISE INTO THE UPPER 60S TO
MID 70S WEDNESDAY AS THE SFC HIGH OVERHEAD CONTINUES TO SLOWLY SINK
TO OUR SSE. A SLOW WARMING TREND WILL BEGIN WEDNESDAY NIGHT...WITH
THE SFC HIGH LINGERING ACROSS THE OHIO VALLEY AND NEW ENGLAND STATES
THROUGH AT LEAST THE START OF THE NEXT WORK WEEK.
THURSDAY WILL SEE A RETURN OF NEAR NORMAL HIGH TEMPS...IN THE
70S...AS 850MB TEMPS FINALLY RISE INTO THE DOUBLE DIGITS AND...STAY
THERE FOR THE REMAINDER OF THE FCST PERIOD.
THERE WILL BE ONLY FEW SYSTEMS OF NOTE OVER THE WEEK...WITH NW FLOW
ALOFT REMAINING IN PLACE THROUGH THE END OF THE WORK WEEK. THE MAIN
500MB LOW WILL BE SPINNING AROUND AND NEAR QUEBEC THROUGH THURSDAY
BEFORE EJECTING NE IN THE MAIN FLOW AROUND THE STRONGER POLAR LOW. A
SERIES OF SHORTWAVES WILL ATTEMPT TO ROUND THE HIGH AMPLITUDE RIDGE
OVER MUCH OF THE WESTERN STATES EARLY TO MID WEEK...
SEEING A SFC LOW TRACKING FROM S ALBERT AND SASKATCHEWAN ON FRIDAY
TO S CENTRAL CANADA OVER THE WEEKEND. THE 12/12Z ECMWF IS MUCH
QUICKER TO PUSH THE SFC LOW ACROSS HUDSON BAY OVER THE WEEKEND.
THERE ARE SIGNIFICANT ENOUGH TIMING DIFFERENCES BETWEEN THE
AVAILABLE GUIDANCE TO KEEP ONLY LIGHT CHANCE POPS IN THE FCST AS
WARM BUT MAINLY DRY AIR PUSHES IN ON SW WINDS AT THE SFC SATURDAY
THROUGH THE END OF THIS FCST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 736 AM EDT TUE AUG 13 2013
MORE INSTABILITY CU/SC WILL DEVELOP THIS MORNING WITH THE ONSET OF
DAYTIME HEATING AND THE APPROACH OF ANOTHER DISTURBANCE...BUT
CONDITIONS ARE LIKELY TO BE VFR. THE BEST CHANCE FOR SOME MVFR CIGS
LATER THIS MORNING INTO THE AFTERNOON WILL BE AT SAW WITH MORE
FAVORABLE UPSLOPE AND GUSTY N WIND.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT TUE AUG 13 2013
NRLY WINDS OF 15 TO 20 KNOTS OVER THE ERN PORTIONF OF LAKE SUPERIOR
WILL DIMINISH TONIGHT AS HIGH PRES BUILDS INTO THE REGION. AS THE
HIGH SINKS TO THE SOUTH WED INTO WED NIGHT WRLY WINDS OF 15 TO 20
KNOTS ARE ALSO EXPECTED OVER CNTRL AND ERN LAKE SUPERIOR.
OTHERWISE...WINDS AOB 15 KNOTS WILL PREVAIL INTO SATURDAY.
&&
.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 GAYLORD MI
705 AM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.UPDATE...
ISSUED AT 657 AM EDT TUE AUG 13 2013
INCREASED WIND GUSTS IN A FEW SPOTS...MAINLY OVER THE GREAT
LAKES...PER LATEST OBS AND INCREASING INSTABILITY. LOW LEVEL
MOISTURE EXPECTED TO DEVELOP INTO A PERIOD OF MOSTLY CLOUDY
SKIES...OF WHICH DID MAKE A CHANGE TO EXTEND THIS CLOUDIEST TIME
PERIOD. OTHERWISE...FORECAST LOOKING GOOD.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 657 AM EDT TUE AUG 13 2013
COLD ADVECTION BEHIND COLD FRONT LAST NIGHT HAS RESULTED IN
POCKETS OF MVFR CIGS. THIS SHOULD BE MORE PREVALENT OVER THE NEXT
FEW HOURS WITH SUNUP AND FCST SOUNDINGS SHOWING POTENTIAL TRAPPING
INVERSION. ONGOING TAFS ARE REALLY HARD TO ARGUE...AS THINGS ARE
QUITE TEMPORARY RIGHT NOW ON THE MVFR FRONT. MORE PREVAILING
THROUGH EARLY AFTERNOON...WHICH IS WHAT THE TAFS PORTRAY. DRYING
THROUGH THE DAY AND LOSS OF SUN WILL LEAD TO PREVAILING VFR
CONDITIONS...ALTHOUGH MOISTURE AND INSTABILITY OFF THE LAKE MAY
TRY AND KEEP CLOUDS IN LONGER/REDEVELOP...ESPECIALLY OVERNIGHT.
GUSTY TODAY ALL AREAS...ESPECIALLY ALONG THE LAKESHORES. GUSTS UP
TO 25 KNOTS OUT OF THE NW.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...SD
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
448 AM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT TUE AUG 13 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
QUEBEC INTO NRN ONTARIO RESULTING IN CYCLONIC WNW FLOW THROUGH THE
NRN GREAT LAKES. LITTLE MORE THAN PATCHY MID CLOUDS WERE ASSOCIATED
WITH A SHORTWAVE TROUGH MOVING THROUGH WRN LAKE SUPERIOR WHILE MORE
EXTENSIVE CLOUDS AND A FEW SPRINKLES WERE OBSERVED WITH ANOTHER
SHRTWV JUST UPSTREAM...TO THE N OF LAKE SUPERIOR. AT THE SFC...HIGH
PRES OVER MANITOBA INTO NW MN WAS BUILDING INTO THE WRN LAKES WITH
NRLY FLOW PREVAILING ACROSS LAKE SUPERIOR INTO UPPER MICHIGAN.
TODAY...AS THE SHRTWV FROM N OF THE LAKE AND A POCKET OF LOWER 700 MB
TEMPS AROUND -6C...DROPS THROUGH THE CWA...MODELS SUGGEST THAT SOME
ISOLD SHOWERS WILL BE POSSIBLE FROM LATE THIS MORNING INTO THE EARLY
AFTERNOON...MAINLY THROUGH W CNTRL UPPER MI. IN ITS WAKE...SUBSIDENCE
AND DRYING WILL BUILD QUICKLY INTO THE AREA...ENDING ANY PCPN BY MID
TO LATE AFTERNOON.
TONIGHT...WITH CLEARING SKIES AND LIGHT WINDS AS THE HIGH BUILD INTO
THE REGION...FAVORABLE RADIATIONAL COOLING CONDITIONS IN THE DRY
AIRMASS(PWAT TO AROUND 0.50 INCH OR 50 PCT OR NORMAL) WILL ALLOW
TEMPERATURES TO DROP TOWARD THE LOWER END OF GUIDANCE....INTO THE
MID TO UPPER 30S INLAND WEST. THE TYPICAL COLDER LOCATIONS FROM
CHAMPION AND AMASA TO WATERSMEET...KENTON AND WATERSMEET COULD SEE
SOME PATCHY FROST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 432 AM EDT TUE AUG 13 2013
THE VERY COOL MORNING TEMPS WILL QUICKLY RISE INTO THE UPPER 60S TO
MID 70S WEDNESDAY AS THE SFC HIGH OVERHEAD CONTINUES TO SLOWLY SINK
TO OUR SSE. A SLOW WARMING TREND WILL BEGIN WEDNESDAY NIGHT...WITH
THE SFC HIGH LINGERING ACROSS THE OHIO VALLEY AND NEW ENGLAND STATES
THROUGH AT LEAST THE START OF THE NEXT WORK WEEK.
THURSDAY WILL SEE A RETURN OF NEAR NORMAL HIGH TEMPS...IN THE
70S...AS 850MB TEMPS FINALLY RISE INTO THE DOUBLE DIGITS AND...STAY
THERE FOR THE REMAINDER OF THE FCST PERIOD.
THERE WILL BE ONLY FEW SYSTEMS OF NOTE OVER THE WEEK...WITH NW FLOW
ALOFT REMAINING IN PLACE THROUGH THE END OF THE WORK WEEK. THE MAIN
500MB LOW WILL BE SPINNING AROUND AND NEAR QUEBEC THROUGH THURSDAY
BEFORE EJECTING NE IN THE MAIN FLOW AROUND THE STRONGER POLAR LOW. A
SERIES OF SHORTWAVES WILL ATTEMPT TO ROUND THE HIGH AMPLITUDE RIDGE
OVER MUCH OF THE WESTERN STATES EARLY TO MID WEEK...
SEEING A SFC LOW TRACKING FROM S ALBERT AND SASKATCHEWAN ON FRIDAY
TO S CENTRAL CANADA OVER THE WEEKEND. THE 12/12Z ECMWF IS MUCH
QUICKER TO PUSH THE SFC LOW ACROSS HUDSON BAY OVER THE WEEKEND.
THERE ARE SIGNIFICANT ENOUGH TIMING DIFFERENCES BETWEEN THE
AVAILABLE GUIDANCE TO KEEP ONLY LIGHT CHANCE POPS IN THE FCST AS
WARM BUT MAINLY DRY AIR PUSHES IN ON SW WINDS AT THE SFC SATURDAY
THROUGH THE END OF THIS FCST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 123 AM EDT TUE AUG 13 2013
EXPECT VFR CONDITIONS AND LGT WINDS TNGT AS DRY HI PRES DOMINATES
UPR MI. MORE INSTABILITY CU/SC WL DVLP THIS MRNG AFTER SUNRISE WITH
ONSET OF DAYTIME HEATING AND THE APRCH OF ANOTHER DISTURBANCE...BUT
CONDITIONS ARE LIKELY TO BE VFR. BEST CHC FOR SOME MVFR CIGS LATER
THIS MRNG INTO THE AFTN WL BE AT SAW WITH MORE FVRBL UPSLOPE AND
GUSTY N WIND.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT TUE AUG 13 2013
NRLY WINDS OF 15 TO 20 KNOTS OVER THE ERN PORTIONF OF LAKE SUPERIOR
WILL DIMINISH TONIGHT AS HIGH PRES BUILDS INTO THE REGION. AS THE
HIGH SINKS TO THE SOUTH WED INTO WED NIGHT WRLY WINDS OF 15 TO 20
KNOTS ARE ALSO EXPECTED OVER CNTRL AND ERN LAKE SUPERIOR.
OTHERWISE...WINDS AOB 15 KNOTS WILL PREVAIL INTO SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
419 AM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
&&
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1157 PM EDT MON AUG 12 2013
MVFR CIGS AT TIMES TONIGHT/TUESDAY MORNING. GUSTY NNW WINDS
TUESDAY.
AUTUMN-LIKE WX IN STORE...AS UNSEASONABLY COOL AIR ENTERS THE
REGION BEHIND A DEPARTING COLD FRONT. COOL AIR MOVING OVER THE
WARM GREAT LAKES WILL RESULT IN LAKE-INDUCED CLOUD COVER TONIGHT
INTO TUESDAY. MVFR CIGS EXPECTED AT ALL TAF SITES...IMPROVING TO
VFR DURING THE DAY ON TUESDAY. COULD BE A TOUCH OF DRIZZLE/-RA...
ESPECIALLY TVC/APN...BUT SMALL RISK IS NOT WORTH INCLUDING IN THE
TAFS AT THIS TIME.
NNW-ERLY BREEZE TONIGHT AND TUESDAY...RATHER GUSTY BY MIDDAY
TUESDAY.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...JZ
MARINE...MB
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
640 PM CDT Wed Aug 14 2013
.SHORT TERM...(This Evening through Friday Afternoon)
Issued at 257 PM CDT WED AUG 14 2013
The main focus in the short-term remains a series of shortwave
troughs sinking southeastward across the Plains this evening,
Thursday, and into early Friday. Showers and isolated storms have
developed over portions of eastern Nebraska in association with a
wave currently pushing southeast toward the forecast area; however,
ongoing precipitation will continue to move into fairly dry air this
evening, and may struggle against entrainment. Additionally, upper-
level flow may push the main area of precipitation more east than
south, keeping the bulk of any falling precipitation in central and
southern Iowa. Short-term precipitation trends from the HRRR have
been fairly consistent today, and also generally limit the south and
eastward expansion of showers for this evening and tonight. For now,
have kept PoPs very low and confined to far northwest Missouri prior
to 06z, then have begun to increase chances in the NW to account for
possible regeneration as the low-level jet kicks up early Thursday
morning.
The next system will follow on the heels of tonight`s as it drops
down from eastern Montana on Thursday. Models continue to indicate
that the reinforcement of the eastern trough by a second upper low,
and the retrograding of a broad upper high, will result in more
meridional flow across the Plains for Thursday and Friday. This
subtle change will send the second wave a bit west of the forecast
area, keeping the better rain chances mainly across portions of
central and eastern Kansas. Have left some slight to low-end chance
PoPs mainly across the western tier or two of counties on Thursday
afternoon and Thursday night, but these could likely be cut further
if model trends continue in this direction. Any precipitation that
does brush the area will sink southward on Friday morning, leaving
behind quiet conditions by Friday afternoon.
Temperatures through the period will remain ~10 degrees below normal
as cool air continues to filter down the trough and into the eastern
Plains and Ohio River valley, with highs generally topping out in
the upper 70s to lower 80s, and lows in the 50s to lower 60s under
surface high pressure.
.LONG TERM...(Friday Evening through Wednesday)
Issued at 257 PM CDT WED AUG 14 2013
A quiet medium range forecast for the Central Plains as mid-level
ridging currently building over the Rockies begins to move
eastward. Despite the increasing heights, Saturday will likely
remain below seasonal normals as surface and low-level winds remain
light to southeast. By Sunday, we`ll begin to see a steady climb
back to or even above normal as winds turn southerly and warmer air
begins to advect northward.
The first half of next week will again feature quiet conditions as
mid-level flow remains weak. Temperatures will have a chance to
return to the 90 degree mark by Tuesday and Wednesday, a rare feat
this August.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 626 PM CDT WED AUG 14 2013
Complex of rain showers moving through eastern Nebraska,
southeastward into SE Nebraska and SW Iowa. Dry air in place over
most of Western Missouri should hinder the progress of these showers
into area, however during the early to mid morning hours Thursday a
weak impulse will move through the area, which will aid in shower
development across a large portion of western Missouri and eastern
Kansas. The scattered nature of the storms along and near Interstate
70, as well as uncertainty as to southern extent of the showery
activity has precluded a prevailing rain shower group in the TAFS,
however felt as though rain would be in the vicinity of the terminals
near I-70. KSTJ will have a better chance of seeing showery activity
early Thursday morning, but will nail down that time frame as the
showers approach. Aside from the scattered showers, VFR conditions
are expected.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Laflin
LONG TERM...Dux
AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS GLASGOW MT
336 PM MDT TUE AUG 13 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
WARM AND HUMID CONDITIONS HAVE CONTRIBUTED TO ISOLATED THUNDERSTORMS
WITH HEAVY RAIN TODAY. ONE EXAMPLE WAS 2.8" IN SOUTHWEST DANIELS
COUNTY.
SHOWERS PRESENTLY MOVING SE INTO ROOSEVELT COUNTY BUT ATMOSPHERE IS
UNSTABLE TO THE SOUTH WITH CAPE ABOUT 1000 J/KG AND DEWPOINTS IN THE
UPPER 50S TO LOW 60S. CERTAINLY RIPE CONDITIONS FOR HEAVY RAIN. RUC
AND HRRR CONTINUE TO SHOW THIS INTO THE EVENING HOURS MAINLY IN THE
EASTERN ZONES. THREAT SHOULD END THEREAFTER.
ON WEDNESDAY...DIURNAL HEATING WILL SPARK SHOWERS AND THUNDERSTORMS
AGAIN AS UPPER LEVELS REMAIN UNSETTLED WITH LOW LEVEL WARMTH AND
HUMIDITY. NOT CONFIDENT ENOUGH TO PIN-POINT WHERE HEAVY RAINS WILL
OCCUR AND DIDN/T FEEL COMFORTABLE TO BROADBRUSH THIS. SMALL HAIL AND
GUSTY WINDS ARE ALSO POSSIBLE BUT AGAIN DID NOT WANT TO
BROADBRUSH...AND IT/S ALREADY MENTIONED IN THE HWO.
BY THURSDAY...THE UPPER RIDGE BUILDS IN AND SUPPRESSES CONVECTION.
WITH MORE SUNSHINE...TEMPERATURES WILL BE WARMER. AIRMASS WILL BE
MORE HUMID OVER THE EASTERN ZONES BUT ANY THUNDERSTORM DEVELOPMENT
WILL BE OVER THE DAKOTAS. TFJ
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
A GOOD CHUNK OF THE PREVIOUS FORECAST STILL STANDS... BUT A COUPLE
PLACES NEEDED TWEAKING. FIRST... OVERNIGHT LOWS POST FRIDAY RIDGE
NEEDED TO BE DRUG DOWN AS THEY WARMED FAR TOO FAST FOR SOUTHWEST
FOLLOWED BY ZONAL FLOW ALOFT THROUGH EARLY NEXT WEEK. ALSO...
ACTED TO STRIP OUT ZERO POPS FOR THE SAME TIME PERIOD AS
VARIABILITY BEGINS TO CREEP INTO THE FORECAST POST SUNDAY AMONG
OPERATIONAL EC VERSUS ITS ENSEMBLE MEMBERS... WHILE NO REAL
ANALOGS FROM THE PAST 60 DAYS ARE YET AVAILABLE FOR THESE PERIODS.
GAH
PREVIOUS LONG TERM DISCUSSION...
THE LONG TERM FORECAST PERIOD BEGINS WITH A STRONG UPPER LEVEL
RIDGE IN PLACE WITH ITS AXIS DIRECTLY THROUGH NORTHEAST MONTANA.
EXCELLENT MODEL AGREEMENT IN KEEPING THE ENTIRE CWA CONSEQUENTLY
DRY. THIS WILL ALLOW THE HOTTEST TEMPERATURES OF THE SUMMER SEASON
TO FINALLY ARRIVE...TOPPING OUT IN THE LOW TO MID 90S...ALTHOUGH
SOME NUMERICAL GUIDANCE SUGGESTS THAT EVEN THIS MAY BE TOO
CONSERVATIVE FOR FRIDAY AND SATURDAY HIGH TEMPERATURES. FOR NOW
FELT IT WAS BEST TO SHOW A GRADUAL INCREASE UNTIL MORE MODEL
CONSENSUS IS EVIDENT.
WITH A COOL FRONT SET TO MOVE THROUGH THE AREA ON SATURDAY
NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE ON THE HEELS
OF SOME MUCH AWAITED NORTHWESTERLY SURFACE WINDS UNDER
SOUTHWESTERLY FLOW ALOFT COURTESY OF THE UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST COASTAL AREA. THIS UNSETTLED PERIOD SHOULD
REMAIN OVER THE REGION WHILE A SHORT WAVE TROUGH PUSHES THROUGH
THE AREA THROUGH MONDAY MORNING...WITH THE BEST CHANCES FOR PRECIP
FOCUSED FROM SATURDAY NIGHT THROUGH SUNDAY MORNING.
MONDAY AND BEYOND...STRONG SUMMER RIDGING FROM THE SOUTHWEST MOVES
IN AGAIN TO CUT OFF THE PRECIPITATION WITH TEMPERATURES WARMING
BACK UP INTO THE 90S.
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. MVFR POSSIBLE WITH EVENING THUNDER OR
OVERNIGHT FOG.
THUNDER: SCATTERED SHOWERS AND THUNDERSTORMS ARE IN SWING THIS
AFTERNOON NEAR THE KOLF... KSDY... AND KGDV TERMINALS AND MAY
CONTINUE THROUGH THE EARLY EVENING. AMENDMENTS MAY BE NEEDED. AS
USUAL... BRIEF VISIBILITY OBSCURATION AND SUDDEN GUSTY WINDS ARE
POSSIBLE NEAR ANY THUNDERSTORM.
FOG: WHILE CHANCES ARE NOT HIGH ENOUGH TO DIRECTLY INCLUDE IN THE
TAFS... A SMALL CHANCE FOR FOG DOES EXIST AT KOLF OR KSDY TONIGHT.
FOG IS MOST POSSIBLE NEAR THE EXCESS OF MOISTURE FROM SHOWERS
EARLIER IN THE EVENING. BEST WINDOW FOR FOG WOULD BE BETWEEN 08Z
AS WINDS DROPS OFF THROUGH 13Z RIGHT AFTER SUN UP.
AREA WINDS: WINDS WILL BE OUT OF THE SOUTH AND EAST AROUND 10 KTS
SUSTAINED... GUSTING UP TO 15 KTS DURING THE AFTERNOON.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
229 PM MDT TUE AUG 13 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
WARM AND HUMID CONDITIONS HAVE CONTRIBUTED TO ISOLATED THUNDERSTORMS
WITH HEAVY RAIN TODAY. ONE EXAMPLE WAS 2.8" IN SOUTHWEST DANIELS
COUNTY.
SHOWERS PRESENTLY MOVING SE INTO ROOSEVELT COUNTY BUT ATMOSPHERE IS
UNSTABLE TO THE SOUTH WITH CAPE ABOUT 1000 J/KG AND DEWPOINTS IN THE
UPPER 50S TO LOW 60S. CERTAINLY RIPE CONDITIONS FOR HEAVY RAIN. RUC
AND HRRR CONTINUE TO SHOW THIS INTO THE EVENING HOURS MAINLY IN THE
EASTERN ZONES. THREAT SHOULD END THEREAFTER.
ON WEDNESDAY...DIURNAL HEATING WILL SPARK SHOWERS AND THUNDERSTORMS
AGAIN AS UPPER LEVELS REMAIN UNSETTLED WITH LOW LEVEL WARMTH AND
HUMIDITY. NOT CONFIDENT ENOUGH TO PIN-POINT WHERE HEAVY RAINS WILL
OCCUR AND DIDN/T FEEL COMFORTABLE TO BROADBRUSH THIS. SMALL HAIL AND
GUSTY WINDS ARE ALSO POSSIBLE BUT AGAIN DID NOT WANT TO
BROADBRUSH...AND IT/S ALREADY MENTIONED IN THE HWO.
BY THURSDAY...THE UPPER RIDGE BUILDS IN AND SUPPRESSES CONVECTION.
WITH MORE SUNSHINE...TEMPERATURES WILL BE WARMER. AIRMASS WILL BE
MORE HUMID OVER THE EASTERN ZONES BUT ANY THUNDERSTORM DEVELOPMENT
WILL BE OVER THE DAKOTAS. TFJ
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
A GOOD CHUNK OF THE PREVIOUS FORECAST STILL STANDS... BUT A COUPLE
PLACES NEEDED TWEAKING. FIRST... OVERNIGHT LOWS POST FRIDAY RIDGE
NEEDED TO BE DRUG DOWN AS THEY WARMED FAR TOO FAST FOR SOUTHWEST
FOLLOWED BY ZONAL FLOW ALOFT THROUGH EARLY NEXT WEEK. ALSO...
ACTED TO STRIP OUT ZERO POPS FOR THE SAME TIME PERIOD AS
VARIABILITY BEGINS TO CREEP INTO THE FORECAST POST SUNDAY AMOUNG
OPERATIONAL EC VERSUS ITS ENSEMBLE MEMBERS... WHILE NO REAL
ANALOGS FROM THE PAST 60 DAYS ARE YET AVAILABLE FOR THESE PERIODS.
GAH
PREVIOUS LONG TERM DISCUSSION...
THE LONG TERM FORECAST PERIOD BEGINS WITH A STRONG UPPER LEVEL
RIDGE IN PLACE WITH ITS AXIS DIRECTLY THROUGH NORTHEAST MONTANA.
EXCELLENT MODEL AGREEMENT IN KEEPING THE ENTIRE CWA CONSEQUENTLY
DRY. THIS WILL ALLOW THE HOTTEST TEMPERATURES OF THE SUMMER SEASON
TO FINALLY ARRIVE...TOPPING OUT IN THE LOW TO MID 90S...ALTHOUGH
SOME NUMERICAL GUIDANCE SUGGESTS THAT EVEN THIS MAY BE TOO
CONSERVATIVE FOR FRIDAY AND SATURDAY HIGH TEMPERATURES. FOR NOW
FELT IT WAS BEST TO SHOW A GRADUAL INCREASE UNTIL MORE MODEL
CONSENSUS IS EVIDENT.
WITH A COOL FRONT SET TO MOVE THROUGH THE AREA ON SATURDAY
NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE ON THE HEELS
OF SOME MUCH AWAITED NORTHWESTERLY SURFACE WINDS UNDER
SOUTHWESTERLY FLOW ALOFT COURTESY OF THE UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST COASTAL AREA. THIS UNSETTLED PERIOD SHOULD
REMAIN OVER THE REGION WHILE A SHORT WAVE TROUGH PUSHES THROUGH
THE AREA THROUGH MONDAY MORNING...WITH THE BEST CHANCES FOR PRECIP
FOCUSED FROM SATURDAY NIGHT THROUGH SUNDAY MORNING.
MONDAY AND BEYOND...STRONG SUMMER RIDGING FROM THE SOUTHWEST MOVES
IN AGAIN TO CUT OFF THE PRECIPITATION WITH TEMPERATURES WARMING
BACK UP INTO THE 90S.
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. MVFR POSSIBLE WITH THUNDER OR HAZE.
THUNDER: THE EDGE OF A RIDGE WILL PROVIDE ENOUGH LIFT FOR SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP NEAR THE KOLF... KSDY... AND KGDV
TERMINALS THIS AFTERNOON... HOWEVER CHANCES ARE NOT HIGH ENOUGH TO
PLACE DIRECTLY IN THE TAFS. THEREFORE WILL GO WITH CB/S UNTIL KICK
OFF TIME AROUND 18 TO 21Z AND AMEND AS NEEDED. AS USUAL... BRIEF
VISIBILITY OBSCURATION AND SUDDEN GUSTY WINDS ARE POSSIBLE NEAR
ANY THUNDERSTORM.
HAZE: HAZE FROM FIRES TO THE WEST HAS REDUCED VISIBILITY TO WELL
LESS THAN 20 MILES AT TIMES AND ACCORDING TO PREVIOUS OBSERVATIONS
ON RARE OCCASIONS CAN REACH THE MVFR OBSCURATION OF 5 MILES.
HOWEVER... THIS IS FAR TOO RARE TO PLACE IN THE TAFS DIRECTLY.
WILL AMEND IF BECOMES NECESSARY.
AREA WINDS: WINDS WILL BE OUT OF THE SOUTH AND EAST AROUND 10 KTS
SUSTAINED... GUSTING UP TO 15 KTS DURING THE AFTERNOON.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
918 AM MDT TUE AUG 13 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
BEST INSTABILITY LATER TODAY SHOULD BE OCCURRING OVER THE EASTERN
ZONES WHERE SURFACE BOUNDARY IS LOCATED. LEANED ON RUC AND HRRR WITH
THE UPDATE AS THEY HAVE ACTIVITY IN THIS AREA. QUITE A BIT OF
MOISTURE IN THE COLUMN THIS MORNING WITH 1.18" PRECIPITAL WATER...SO
HEAVY RAIN WILL BE POSSIBLE WITH SLOW MOVING STORMS. REST OF
FORECAST LOOKED GOOD. TFJ
PREVIOUS DISCUSSION...
A SLOW MOVING FRONTAL BOUNDARY WILL COMBINE WITH SHORTWAVES
OVERTOPPING AN UPPER RIDGE AND MOIST UNSTABLE AIRMASS TO PRODUCE
THUNDERSTORMS AT TIMES TODAY THROUGH WEDNESDAY NIGHT. WITH
PRECIPITABLE WATER EXPECTED TO BE BETWEEN AN INCH AND 1.25
INCHES... LOCALLY HEAVY RAIN IS ALSO POSSIBLE WHICH MAY PRODUCE
FLASH FLOODING. MODELS DIFFER IN WHEN AND WHERE IT WILL RAIN WITH
THE INDIVIDUAL WAVES. WILL BROADBRUSH ISOLATED TO SCATTERED
THUNDERSTORMS TODAY AND TONIGHT WITH HEAVY RAIN POSSIBLE FOLLOWED
BY ISOLATED TO SCATTERED THUNDERSTORMS ON WEDNESDAY AND A CHANCE
OF THUNDERSTORMS WEDNESDAY NIGHT.
UPPER RIDGE STRENGTHENS OVER THE FORECAST AREA ON THURSDAY WITH
SOMEWHAT DRIER... WARMER AND MORE STABLE AIRMASS WHICH WILL LIMIT THE
CHANCES OF THUNDERSTORMS. WITH SHORTWAVE LACKING IN THE FLOW
ALOFT... WILL GO WITH A DRY FORECAST FOR NOW. FORRESTER
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE LONG TERM FORECAST PERIOD BEGINS WITH A STRONG UPPER LEVEL
RIDGE IN PLACE WITH ITS AXIS DIRECTLY THROUGH NORTHEAST MONTANA.
EXCELLENT MODEL AGREEMENT IN KEEPING THE ENTIRE CWA CONSEQUENTLY
DRY. THIS WILL ALLOW THE HOTTEST TEMPERATURES OF THE SUMMER SEASON
TO FINALLY ARRIVE...TOPPING OUT IN THE LOW TO MID 90S...ALTHOUGH
SOME NUMERICAL GUIDANCE SUGGESTS THAT EVEN THIS MAY BE TOO
CONSERVATIVE FOR FRIDAY AND SATURDAY HIGH TEMPERATURES. FOR NOW
FELT IT WAS BEST TO SHOW A GRADUAL INCREASE UNTIL MORE MODEL
CONSENSUS IS EVIDENT.
WITH A COOL FRONT SET TO MOVE THROUGH THE AREA ON SATURDAY
NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE ON THE HEELS
OF SOME MUCH AWAITED NORTHWESTERLY SURFACE WINDS UNDER
SOUTHWESTERLY FLOW ALOFT COURTESY OF THE UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST COASTAL AREA. THIS UNSETTLED PERIOD SHOULD
REMAIN OVER THE REGION WHILE A SHORT WAVE TROUGH PUSHES THROUGH
THE AREA THROUGH MONDAY MORNING...WITH THE BEST CHANCES FOR PRECIP
FOCUSED FROM SATURDAY NIGHT THROUGH SUNDAY MORNING.
MONDAY AND BEYOND...STRONG SUMMER RIDGING FROM THE SOUTHWEST MOVES
IN AGAIN TO CUT OFF THE PRECIPITATION WITH TEMPERATURES WARMING
BACK UP INTO THE 90S.
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. MVFR POSSIBLE WITH THUNDER OR HAZE.
THUNDER: THE EDGE OF A RIDGE WILL PROVIDE ENOUGH LIFT FOR SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP NEAR THE KOLF... KSDY... AND KGDV
TERMINALS THIS AFTERNOON... HOWEVER CHANCES ARE NOT HIGH ENOUGH TO
PLACE DIRECTLY IN THE TAFS. THEREFORE WILL GO WITH CB/S UNTIL KICK
OFF TIME AROUND 18 TO 21Z AND AMEND AS NEEDED. AS USUAL... BRIEF
VISIBILITY OBSCURATION AND SUDDEN GUSTY WINDS ARE POSSIBLE NEAR
ANY THUNDERSTORM.
HAZE: HAZE FROM FIRES TO THE WEST HAS REDUCED VISIBILITY TO WELL
LESS THAN 20 MILES AT TIMES AND ACCORDING TO PREVIOUS OBSERVATIONS
ON RARE OCCASIONS CAN REACH THE MVFR OBSCURATION OF 5 MILES.
HOWEVER... THIS IS FAR TOO RARE TO PLACE IN THE TAFS DIRECTLY.
WILL AMEND IF BECOMES NECESSARY.
AREA WINDS: WINDS WILL BE OUT OF THE SOUTH AND EAST AROUND 10 KTS
SUSTAINED... GUSTING UP TO 15 KTS DURING THE AFTERNOON.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1201 AM MDT Tue Aug 13 2013
.UPDATE...
Increased POPS for the rest of the night for the northeast zones as
showers and thunderstorms continue to develop along multiple outflow
boundaries. Expect coverage of precipitation to begin decreasing in
a few hours as the shortwave and associated lift move east. Langlieb
&&
.AVIATION...
UPDATED 0505Z.
Scattered thunderstorms continue across central and north central MT
from northeast of KGTF to east of KHVR, producing good amount of
lightning and moderate to locally heavy rainfall. Storms have also
been putting out gusty outflow winds of 25-35 kts. Storm cells are
expected to gradually dissipate between now and 08Z with ceilings
increasing to greater than 10000 ft at that time. Clear skies to
scattered clouds and light winds expected overnight. Tuesday will
be near-repeat of Monday`s weather as scattered thunderstorms
develop again during the afternoon/evening.
Waranauskas
&&
.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Aug 12 2013/
Tonight through Wednesday...Overall pattern has changed little
from Sunday. The airmass is a bit more unstable this afternoon
with CAPE values of 1000 to 2000 J/kg across the northern portion
of the county warning area. Shear values, though not overly
impressive, have also increased from earlier this morning and with
high precipitable water, the result is thunderstorm development.
The weak steering flow aloft will make very slow movers with these
storms and heavy rain will be the primary threat (although some
hail cannot be ruled out). HRRR and RUC analysis continue to
develop thunderstorms over Great Falls as late as 04 to 05z. Drier
conditions over southwest Montana will translate to isolated
thunderstorms this evening. Enough instability will exist Tuesday
afternoon to allow isolated to scattered thunderstorms to develop
again though areal coverage should be less. Rising H5 heights
Wednesday will herald the beginning of a drier and warmer regime.
Temperatures will be near or slightly above seasonal averages.
Emanuel
Wednesday Night through Monday...Medium range forecast remains
relatively unchanged tonight. Models are in good agreement from
mid-week until early in the weekend and indicate that an upper level
ridge will be over the Rocky Mountains for a very warm and generally
dry forecast period. Model consensus for the weekend through early
next week remains elusive. Models agree that the ridge will be
pushed eastward on Saturday as a broad upper level trough moves
inland along the west coast. Beyond Saturday, models set up a
roughly zonal flow aloft but bring multiple and frequent short waves
over the region. Unfortunately, the wave phase and speed differ
markedly between the models and significant disagreement with regard
to pops/clouds/weather timing arises. Am sticking with a solution
that trends temperatures slightly cooler and increases pops toward
climatology for the weekend through Monday. mpj
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 84 55 86 / 40 30 30 20
CTB 52 82 52 85 / 40 30 20 10
HLN 57 86 57 89 / 30 30 40 20
BZN 50 85 49 86 / 30 30 30 20
WEY 39 78 37 78 / 10 20 20 10
DLN 49 83 49 84 / 20 20 20 20
HVR 57 82 56 84 / 40 20 30 20
LWT 54 81 53 81 / 40 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Suk
LONG TERM...mpj
AVIATION...WARANAUSKAS
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1105 PM MDT Mon Aug 12 2013
AVIATION SECTION UPDATED
.UPDATE...
Increased pops and QPF across much of the eastern part of the zone
as showers and thunderstorms continue to move across central
Montana. The active weather pattern will continue through the
evening hours with some of the shower activity lasting well past
midnight. No significant changes to other parts of the forecast as
most of the impact tonight will be associated with the severe
thunderstorms. Suk
&&
.AVIATION...
UPDATED 0505Z.
Scattered thunderstorms continue across central and north central MT
from northeast of KGTF to east of KHVR, producing good amount of
lightning and moderate to locally heavy rainfall. Storms have also
been putting out gusty outflow winds of 25-35 kts. Storm cells are
expected to gradually dissipate between now and 08Z with ceilings
increasing to greater than 10000 ft at that time. Clear skies to
scattered clouds and light winds expected overnight. Tuesday will
be near-repeat of Monday`s weather as scattered thunderstorms
develop again during the afternoon/evening.
Waranauskas
&&
.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Aug 12 2013/
Tonight through Wednesday...Overall pattern has changed little
from Sunday. The airmass is a bit more unstable this afternoon
with CAPE values of 1000 to 2000 J/kg across the northern portion
of the county warning area. Shear values, though not overly
impressive, have also increased from earlier this morning and with
high precipitable water, the result is thunderstorm development.
The weak steering flow aloft will make very slow movers with these
storms and heavy rain will be the primary threat (although some
hail cannot be ruled out). HRRR and RUC analysis continue to
develop thunderstorms over Great Falls as late as 04 to 05z. Drier
conditions over southwest Montana will translate to isolated
thunderstorms this evening. Enough instability will exist Tuesday
afternoon to allow isolated to scattered thunderstorms to develop
again though areal coverage should be less. Rising H5 heights
Wednesday will herald the beginning of a drier and warmer regime.
Temperatures will be near or slightly above seasonal averages.
Emanuel
Wednesday Night through Monday...Medium range forecast remains
relatively unchanged tonight. Models are in good agreement from
mid-week until early in the weekend and indicate that an upper level
ridge will be over the Rocky Mountains for a very warm and generally
dry forecast period. Model consensus for the weekend through early
next week remains elusive. Models agree that the ridge will be
pushed eastward on Saturday as a broad upper level trough moves
inland along the west coast. Beyond Saturday, models set up a
roughly zonal flow aloft but bring multiple and frequent short waves
over the region. Unfortunately, the wave phase and speed differ
markedly between the models and significant disagreement with regard
to pops/clouds/weather timing arises. Am sticking with a solution
that trends temperatures slightly cooler and increases pops toward
climatology for the weekend through Monday. mpj
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 84 55 86 / 40 30 30 20
CTB 52 82 52 85 / 40 30 20 10
HLN 57 86 57 89 / 30 30 40 20
BZN 50 85 49 86 / 30 30 30 20
WEY 39 78 37 78 / 10 20 20 10
DLN 49 83 49 84 / 20 20 20 20
HVR 57 82 56 84 / 40 20 30 20
LWT 54 81 53 81 / 40 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Suk
LONG TERM...mpj
AVIATION...WARANAUSKAS
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
946 PM CDT WED AUG 14 2013
.SYNOPSIS...
ISSUED AT 330 PM CDT WED AUG 14 2013
SHOWER AND THUNDERSTORM ACTIVITY CURRENTLY EXISTS ACROSS NORTH-
CENTRAL NEBRASKA AND IS MOVING EASTWARD SLOWLY. NEBRASKA IS UNDER
NORTHWEST FLOW ALOFT WITH AN UPPER LEVEL WAVE IN EASTERN NEBRASKA
AND ANOTHER OVER MONTANA. LOW LEVEL FLOW IS GENERALLY SOUTHERLY
WITH AN AREA OF LOW PRESSURE OVER THE INTERMOUNTAIN WEST AND HIGH
PRESSURE OVER THE UPPER MISSISSIPPI RIVER VALLEY. A WEAK BOUNDARY
EXISTS ACROSS CENTRAL NEBRASKA...RUNNING FROM HOLT COUNTY
SOUTHWEST TO CHASE COUNTY.
&&
.UPDATE...
ISSUED AT 945 PM CDT WED AUG 14 2013
HAVE ADJUSTED PRECIPITATION CHANCES ACROSS THE AREA NOW THAT
ISOLATED CONVECTION HAS ENDED ACROSS THE AREA...FOR NOW.
HOWEVER...CONVECTIVE COMPLEXES REMAIN ACROSS SOUTHWEST SD AND
NORTHEAST CO. HRRR DOES TRY TO KEEP THE SD COMPLEX TOGETHER LONG
ENOUGH TO MOVE INTO THE PANHANDLE AND INTO THE CENTRAL SANDHILLS.
MID LEVEL LAPSE RATES WOULD SUPPORT SOME ADDITIONAL DEVELOPMENT SO
HAVE LEFT SMALL CHANCES IN FOR NOW. OTHERWISE ADDED SOME PATCHY
FOG EAST OF HIGHWAY 83 WHERE SMALL TEMP/DEW POINT SPREADS EXIST.
UPDATE ISSUED AT 706 PM CDT WED AUG 14 2013
HAVE UPDATED EVENING FCST TO SLIGHTLY ADJUST PRECIP CHANCES.
THUNDERSTORMS SHOWING A QUICK DECREASE IN COVERAGE AND INTENSITY
OVER THE LAST 15 MINS. ADDITIONAL CONVECTION FURTHER WEST WILL
APPROACH THE AREA LATER THIS EVENING...BUT OVERALL MID LEVEL LAPSE
RATES DOES NOT LOOK FAVORABLE AT THIS POINT BUT WILL LOOK FURTHER
INTO THIS. OTHERWISE REMAINDER OF FCST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
THE THUNDERSTORM COMPLEX THAT STARTED OVER THE NORTHEAST HAS
LINGERED THERE TODAY DUE TO A FAVORABLE LOW LEVEL JET...SOME
MODEST ELEVATED CAPE...AND UPPER SUPPORT. A SURFACE BOUNDARY
CURRENTLY RUNS FROM HOLT TO CHASE COUNTIES AND MAY BE THE FOCUS
FOR A FEW THUNDERSTORMS THIS AFTERNOON/EVENING. THE SEVERE THREAT
IS LOW AS DEEP SHEAR IS RUNNING AT 25 TO 30 KTS. AN ISOLATED
SEVERE STORM OR TWO CANNOT BE RULED OUT...HOWEVER. AN UPPER LEVEL
WAVE WILL PUSH INTO THE AREA FROM THE NORTHWEST LATE TONIGHT AND
TOMORROW MORNING. AHEAD OF THIS WAVE...CLOUDS WILL INCREASE AND SO
WILL A LOW LEVEL JET ACROSS WESTERN NEBRASKA. BELIEVE THERE MAY BE
SOME LATE NIGHT THUNDERSTORMS ACROSS THE NORTHWEST LATE IN THE
NIGHT AND EARLY TOMORROW MORNING. THE MAIN UPPER WAVE WILL DRIFT
INTO CENTRAL NEBRASKA BY MIDDAY...AND SO BELIEVE ANY THUNDERSTORM
ACTIVITY WOULD BE PRIMARILY DURING THE LATE MORNING TO AFTERNOON
HOURS. SHEAR TOMORROW IS A LITTLE BETTER...30-35 KTS...ACROSS THE
SOUTH. AS A RESULT...SPC HAS ISSUED A SLIGHT RISK FOR SEVERE
WEATHER ACROSS THAT AREA FOR TOMORROW.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
FORECASTING CHALLENGES ARE LINGERING PRECIPITATION THURSDAY
EVENING...FOG POTENTIAL OVERNIGHT THURSDAY NIGHT INTO FRIDAY
MORNING...THEN TEMPERATURES. WITH RESPECT TO THUNDERSTORM CHANCES
THURSDAY EVENING...THE MODELS ARE A LITTLE FASTER WITH SHORTWAVE
ENERGY DROPPING SOUTH THURSDAY ACROSS THE DAKOTAS AND NEBRASKA.
THIS WILL BRING AN EARLIER END TO PRECIPITATION BY LATE THURSDAY
EVENING IN THE SRN CWA. BEHIND THE EXITING CONVECTION...CLEARING
SKIES...STRONG RADIATIONAL COOLING AND MOIST BOUNDARY LAYER CONDS
MAY LEAD TO THE FORMATION OF FOG OVERNIGHT THURSDAY NIGHT INTO
EARLY FRIDAY MORNING. NAM AND GFS BUFR SOUNDINGS INDICATE A
FAVORABLE ENVIRONMENT FOR FOG FORMATION...AS DOES THE MET AND MAV
GUIDANCE ALONG AND SOUTH OF A LINE FROM BIG SPRINGS TO BARTLETT.
DECIDED TO LEAVE FOG MENTION AS PATCHY ATTM...AS SREF
PROBABILITIES ARE RUNNING AROUND 60 PERCENT FOR VISBYS BLO 1SM.
FOR FRIDAY INTO SUNDAY NIGHT...RIDGING WILL BUILD EAST INTO THE
CENTRAL AND NORTHERN PLAINS...LEADING TO NRLY FLOW ALOFT AND
EFFECTIVELY CUTTING OFF ANY CHANCE FOR PCPN FRIDAY THROUGH SUNDAY.
HIGHS WILL BEGIN TO CLIMB FROM THE LOWER TO MID 80S ON FRIDAY...TO
THE MID 80S TO AROUND 90 BY THE END OF THE WEEKEND. FOR HIGHS AND
LOWS...UTILIZED THE ADJMAV GUIDANCE AS IT HAS HAD THE BEST
VERIFICATION OVER THE PAST COUPLE OF WEEKS AND AVOIDED THE HIGHER
MEX NUMBERS WHICH HAD HIGHS IN THE 90S BY SUNDAY INTO MONDAY.
THINKING ATTM IS THAT THE MEX NUMBERS ARE TOO HIGH GIVEN THE HIGH
DEGREE OF SURFACE MOISTURE ACROSS THE AREA. RIDGING ALOFT WILL
BEGIN TO BREAK DOWN SLIGHTLY EARLY NEXT WEEK AS A DISTURBANCE
TRACKS ACROSS SRN CANADA. THIS FEATURE HAS TRENDED WEAKER COMPARED
TO YESTERDAYS MODEL RUNS...WHICH A...FACILITATES DECREASED POPS
NEXT WEEK...AND B...INCREASED HIGH TEMPS...BOTH OF WHICH WERE
IMPLEMENTED WITH THIS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 706 PM CDT WED AUG 14 2013
AVIATION FCST CHALLENGES ARE TSRA CHCS THIS EVENING AND FG/BR
POTENTIAL TWD DAYBREAK...MUCH AS THEY HAVE BEEN LAST COUPLE OF
DAYS. FIRST FOR TSRA CHANCES...BEST POTENTIAL WOULD BE IN THE
SOUTHEAST PORTION OF THE AREA...BUT EVEN THAT LOOKS WANING
QUICKLY. WILL BE MONITORING TSRA MOVING IN FROM FURTHER WEST...BUT
CONVECTION ALLOWING MODELS ARE NOT FAVORABLE FOR THESE AREAS
HOLDING TOGETHER.
NEXT CHALLENGE IS BR/FG POTENTIAL. ONCE AGAIN THE SIGNAL IN THE
MODELS IS MIXED AND THEREFORE CONFIDENCE IS LOW. STILL HAVE
INCLUDED A MENTION OF SCT LOW CIGS AND SOME BR...THOUGH KEEPING
VSBYS AT IFR OR ABOVE. TSRA CHCS RETURN AGAIN TMRW AFTERNOON AS
SIGNIFCANT PV ANOMALY ROTATING SEWD INTO THE HIGH PLAINS. AT THIS
POINT COVERAGE MAY BE IN QUESTION...AND MODELS HAVE GENERALLY BEEN
OVERDOING THIS THE LAST COUPLE OF NIGHTS. CONFIDENCE IS LOW...AND
HAVE LEFT TSRA MENTION OUT OF TAFS FOR THIS TIME FRAME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SYNOPSIS...KNUTSVIG
SHORT TERM...KNUTSVIG
LONG TERM...CLB
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
619 PM CDT WED AUG 14 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
CLOUDS LINGERED ACROSS MUCH OF THE AREA THIS AFTERNOON AND HAS SO
FAR HELPED TO PUT A CAP ON MORE WIDESPREAD CONVECTION. THAT
SAID...INSTABILITY IS BEGINNING TO BUILD...AND WITH SOME NOTABLE
MOISTURE CONVERGENCE AHEAD OF DEVELOPING CONVECTION TO OUR
NORTH...EXPECT THE POTENTIAL FOR ADDITIONAL DEVELOPMENT THROUGH
THE LATE AFTERNOON AND EVENING HOURS. MODELS HAVE NOT HAD A GREAT
HANDLE ON THIS ALL DAY...ALBEIT 12Z WRF AND LATEST HRRR BOTH
ATTEMPTED TO PICK UP ON CONVECTION TO OUR NORTH...TAKING IT
SOUTHWARD THROUGH THE EVENING HOURS. WHILE CONFIDENCE IS NOT
PARTICULARLY HIGH...CONTINUE TO SEE THE POTENTIAL FOR SOME
ADDITIONAL THUNDERSTORM ACTIVITY THROUGH THE EVENING AND INTO THE
OVERNIGHT HOURS AS THERE IS PLENTY OF INSTABILITY TO
TAP...ESPECIALLY WEST OF HIGHWAY 281. THAT SAID...SHEAR IS VERY
WEAK...AND ANY ADDITIONAL STORMS THAT DO DEVELOP ARE NOT EXPECTED
TO BE SEVERE OR WIDESPREAD.
AS WE WORK TOWARDS THURSDAY MORNING AND FOCUS OF INITIAL
CONVECTION SHIFTS SOUTHWARD...COULD SEE SOME PARTIAL
CLEARING...AND WITH LIGHT SOUTHEASTERLY WINDS AND ELEVATED LOW
LEVEL MOISTURE...DECIDED TO INSERT PATCHY FOG INTO THE FORECAST
FOR THE EARLY MORNING HOURS TOMORROW. LATEST HRRR IS INDICATING
POSSIBLY SOME DENSE FOG ACROSS OUR NORTH BY 09Z...BUT WITH
UNCERTAINTY IN TIMING AND AMOUNT OF CLEARING...PATCHY MENTION
SEEMED MORE REASONABLE FOR THE TIME BEING.
AS WE WORK INTO THE DAYTIME HOURS THURSDAY...THE POTENTIAL FOR
SOME STRONG/MARGINALLY SEVERE STORMS WILL BE REALIZED BY EARLY
AFTERNOON AS MODELS ARE PICKING UP ON AN UPPER LEVEL SHORTWAVE
DROPPING DOWN FROM THE NORTH COUPLED WITH THE PRESENCE OF A WEAK
WARM FRONTAL BOUNDARY DRAPED ACROSS THE LOCAL AREA FROM NORTHWEST
TO SOUTHEAST. THIS COMBINATION...WITH PLENTY OF AVAILABLE
INSTABILITY...SHOULD MAKE FOR A MORE ACTIVE AFTERNOON AND
EVENING...AND CONTINUED WITH MENTION OF POTENTIAL SEVERE WEATHER
IN HWO THIS AFTERNOON. WHILE SHEAR IS NOT ALL THAT
IMPRESSIVE...CAPE AND FORCING SHOULD BE SUFFICIENT FOR THE
DEVELOPMENT OF A FEW STORMS WITH MARGINALLY SEVERE HAIL AND
THUNDERSTORM WIND GUSTS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE
PERIOD AND TEMPERATURES.
AN UPPER LEVEL WAVE WILL CONTINUE TO MOVE THROUGH THE AREA THURSDAY
NIGHT. THUNDERSTORMS WILL CONTINUE ACROSS THE AREA DURING THE
EVENING BUT GRADUALLY COME TO AN END FROM NORTHWEST TO SOUTHEAST
DURING THE OVERNIGHT HOURS AND INTO FRIDAY MORNING. MUCAPE REMAINS
AROUND 3000 J/KG DURING THE EVENING BUT DROPS OFF LATER IN THE
NIGHT. ON FRIDAY THE UPPER LEVEL RIDGE IN THE ROCKIES STARTS TO
SLIDE TO THE EAST AND WITH THE RAIN MOVING OUT...TEMPERATURES WILL
WARM SOME.
FRIDAY NIGHT INTO SUNDAY THE UPPER LEVEL RIDGE BUILDS ACROSS THE
AREA AND EXPECT DRY CONDITIONS AND TEMPERATURES WILL CONTINUE TO
WARM A FEW DEGREES.
AN UPPER LEVEL WAVE WILL MOVE OVER THE RIDGE SUNDAY NIGHT AND BRING
A SMALL CHANCE FOR THUNDERSTORMS. THERE SHOULD BE A BRIEF BREAK FROM
THUNDERSTORMS AGAIN ON MONDAY BUT ANOTHER UPPER LEVEL WAVE MOVES
INTO THE AREA MONDAY NIGHT AND TUESDAY. THERE IS ALSO A WEAK COLD
FRONT THAT MOVES THROUGH THE FORECAST AREA MONDAY NIGHT.
THUNDERSTORMS ARE EXPECTED ALONG AND BEHIND THE COLD FRONT. DESPITE
THE COLD FRONT TEMPERATURES SHOULD CONTINUE TO WARM A DEGREE OR TWO
EACH DAY AS THE UPPER RIDGE SETTLES OVER THE PLAINS.
TUESDAY NIGHT AND WEDNESDAY THE MODELS HAVE SOME DIFFERENCES IN THE
MAIN PATTERN. THE GFS HAS AN UPPER RIDGE...WHILE THE ECMWF HAS A
TROUGH MOVING THROUGH. WILL HAVE A SMALL CHANCE FOR THUNDERSTORMS
FOR NOW. THE TEMPERATURE SHOULD REMAIN ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 613 PM CDT WED AUG 14 2013
THUNDERSTORMS NORTH OF THE TERMINAL HAVE SHOWN SIGNS OF WEAKENING
EARLY THIS EVENING AND HAVE NOT INCLUDED IN THE TAF ATTM...AND
WILL MONITOR. SOME POTENTIAL EXISTS FOR FOG DEVELOPMENT LATE
TONIGHT INTO THURSDAY MORNING AND HAVE KEPT VSBYS AT MVFR FOR NOW.
REDEVELOPMENT OF CONVECTION IS FORECAST FOR THURSDAY AFTN/EVE OR
THE LATTER TAF HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...JCB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
520 PM CDT TUE AUG 13 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
WE HAD A MESOSCALE CONVECTIVE VORTEX (MCV) TRACK ACROSS OUR FORECAST
AREA THIS MORNING INTO THE EARLY AFTERNOON HOURS. THIS BROUGHT
WIDESPREAD RAINFALL TO OUR FORECAST AREA AND HAS WORKED OVER THE
ATMOSPHERE ENOUGH THAT ADDITIONAL PRECIPITATION THIS EVENING INTO
TONIGHT IS UNLIKELY. THE CONVECTION THAT TRACKED THROUGH OUR AREA
HAS NOW PASSED SOUTH INTO CENTRAL KANSAS AND NEW STORMS HAVE ALSO
FORMED TO OUR WEST OVER THE HIGH PLAINS OF WESTERN NEBRASKA.
THE WESTERN NEBRASKA THUNDERSTORMS HAVE FORMED ALONG THE LEADING
EDGE OF THE NEXT SHORTWAVE THAT IS TRACKING SOUTHEAST FROM EASTERN
WYOMING/SOUTHWEST SOUTH DAKOTA INTO WESTERN NEBRASKA. DEEP MOISTURE
CONVERGENCE AND AFTERNOON DESTABILIZATION IS ALSO MAXIMIZED ACROSS
WESTERN NEBRASKA INTO THE BLACK HILLS AND THIS IS WHERE ADDITIONAL
THUNDERSTORMS ARE EXPECTED TO FORM THIS EVENING. THIS IS A WEAKLY
SHEARED ENVIRONMENT AND STORM PROPAGATION WILL GENERALLY BE A SLOW
DRIFT TO THE SOUTH...WHICH SHOULD KEEP THE WESTERN STORMS JUST TO
THE WEST OF OUR FORECAST AREA TONIGHT. THERE IS AN OUTSIDE CHANCE OF
OUR WESTERN ZONES SEEING A PREDAWN SHOWER/THUNDERSTORM SHOULD THE
BLACK HILLS CONVECTION MAKE IT THIS FAR SOUTHEAST. HOWEVER...MOST
FORECAST MODEL DATA KEEPS ALL CONVECTION WEST OF OUR FORECAST AREA
TONIGHT AND THUS WE WILL KEEP ALL ZONES DRY TONIGHT...WHILE KEEPING
AN EYE ON THE WEST FOR THE POSSIBILITY OF NEEDING TO THROW SOME POPS
IN THE FORECAST DEPENDING ON FUTURE RADAR TRENDS.
THERE IS SOME POTENTIAL OF FOG TONIGHT GIVEN THE RECENT WIDESPREAD
RAINFALL. HOWEVER...FORECAST MODELS ARE MIXED ON FOG POTENTIAL WITH
THE HRRR MORE FAVORABLE FOR FOG WHILE THE SREF WOULD NOT GIVE US ANY
FOG. ULTIMATELY FOG WILL LARGELY HINGE ON CLOUD COVER AND SUBSEQUENT
COOLING. HAVE LEFT FOG OUT OF THE FORECAST FOR NOW...BUT SHOULD WE
CLEAR OUT AND REMAIN CLEAR THROUGH MOST OF THE NIGHT...THEN COOLING
MIGHT BE ADEQUATE FOR SOME AREAS OF FOG EARLY WEDNESDAY MORNING.
WEDNESDAY...A SHORT WAVE TROUGH WILL TRACK SOUTHEAST ACROSS WESTERN
NEBRASKA. INSTABILITY AND DEEP LAYER SHEAR WILL BE FAIRLY WEAK TO
MODEST AT BEST AND THUS AM NOT EXPECTING SEVERE WEATHER...BUT CAN
NOT RULE OUT A COUPLE OF STRONG THUNDERSTORMS IN ASSOCIATION WITH
PEAK AFTERNOON HEATING. THE BEST CHANCE OF THUNDERSTORMS WILL BE
ACROSS OUR WESTERN ZONES AND TO THE WEST OF OUR FORECAST AREA IN
ASSOCIATION WITH THE APPROACHING SHORTWAVE. TEMPERATURES WILL REMAIN
COOL FOR AUGUST DUE TO A CONTINUATION OF THE COOL AIRMASS
OVERHEAD...CLOUDS...AND POSSIBLE PRECIPITATION. HIGHS WILL GENERALLY
BE IN THE UPPER 70S TO LOWER 80S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
THE MAIN HIGHLIGHTS OF THIS 6-DAY PERIOD ARE A CONTINUATION OF
CHALLENGING SHOWER/THUNDERSTORM CHANCES IN THE WED NIGHT THROUGH
FRIDAY TIME FRAME WHICH MIGHT EVEN FEATURE A STRONG-SEVERE STORM
THREAT CENTERED ON THURSDAY...FOLLOWED BY WHAT APPEARS TO BE A
PREDOMINANTLY DRY WEEKEND...AND THEN A RETURN TO VERY UNCERTAIN
RAIN CHANCES IN THE SUNDAY NIGHT-TUESDAY TIME FRAME AS THE PATTERN
CHANGES A BIT. ITS BEEN A TOUGH GO OF IT LATELY TRYING TO
DETERMINE HOW HARD TO HIT...OR BACK OFF...POPS EVEN IN THE FIRST
24 HOURS...SO THESE UNCERTAINTIES CONTINUE TO BE MAGNIFIED EVEN IN
THE DAY 2-3 TIME FRAME. OF HIGHER CONFIDENCE IS THAT A FAIRLY
REMARKABLE RUN OF SUB-90 DEGREE TEMPS WILL CONTINUE...WITH THE
MAJORITY OF THE CWA FORECAST TO TOP OUT IN THE LOW-MID 80S DURING
THIS TIME FRAME...WITH KS ZONES AS USUAL MOST FAVORED TO REACH
UPPER 80S ON A FEW DAYS. AS FOR LOW TEMPS...EVERY NIGHT IS
EXPECTED TO BE FAIRLY SIMILAR AND RATHER UNIFORM ACROSS THE
CWA...EITHER IN THE LOW OR MID 60S.
STARTING OFF WEDNESDAY EVENING/NIGHT...GAVE A BEST-STAB AT TWO
6-HOUR POP BLOCKS HEAVILY BASED ON MET/MAV GUIDANCE BLEND...WITH
THE EVENING PERIOD FEATURING 20S-40S...AND THE LATE NIGHT PERIOD
RANGING FROM ONLY 20S FAR WEST TO 50S IN EASTERN-MOST NEB ZONES.
IN OTHER WORDS...THERE IS A DECENT CHANCE THAT PARTS OF THE CWA
WILL SEE RAIN...BUT CONFIDENCE IN TIMING/PLACEMENT PRECLUDES
LIKELY POPS ANYWHERE YET. ON THE LARGE-SCALE ALOFT...LEGITIMATE
NORTHWEST-FLOW IS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN A
RIDGE AXIS EXTENDING NORTHWARD ACROSS THE ROCKIES FROM NORTHERN
MEXICO INTO SOUTHWEST CANADA...AND A BROAD TROUGH ANCHORED OVER
SOUTHEAST CANADA/THE NORTHEAST CONUS. ON A MORE LOCAL/REGIONAL
LEVEL...THE CWA IS PROGGED TO REMAIN UNDER/NEAR THE MAIN TRACK OF
LOW-AMPLITUDE SHORTWAVE TROUGHS RIPPLING THROUGH THE NORTHWEST
FLOW. STARTING OFF RIGHT AWAY WED EVENING AT 00Z/7PM...ITS
EXPECTED THAT AT LEAST A SMALL PART OF THE CWA SHOULD BE SEEING
ACTIVITY PERSISTING FROM THE LATE AFTERNOON HOURS...ALTHOUGH MODEL
QPF/REFLECTIVITY FIELDS VARY CONSIDERABLY ON THE MOST FAVORED
AREA. AS THE NIGHT WEARS ON...THERE IS A DECENT SIGNAL FOR WARM
AIR ADVECTION/MOISTURE TRANSPORT IN THE 850-700 MILLIBAR
LAYER...WITHIN THE AXIS OF A MODEST 20+KT SOUTHWESTERLY LOW LEVEL
JET. PER THE 12Z/18Z NAM AND LAST FEW SREF RUNS...THIS WOULD FAVOR
EASTERN ZONES FOR THE HIGHEST LATE NIGHT POPS...WHILE THE
ECWMF/GFS WOULD MORE-SO FAVOR CENTRAL/SOUTHWEST ZONES. AS FOR
THUNDERSTORM INTENSITY...ALTHOUGH NOT EXPECTING A WIDESPREAD
NOCTURNAL SEVERE THREAT...CERTAINLY A FEW STRONG TO MARGINALLY
SEVERE STORMS WITH MAINLY A HAIL/LOCALLY HEAVY RAIN THREAT CANNOT
BE RULED OUT GIVEN MUCAPE INCREASING TO AT LEAST 500-1000 J/KG IN
THE PRESENCE OF AROUND 25KT OF DEEP LAYER SHEAR.
THURSDAY/THURSDAY NIGHT...THIS 24 HOURS WOULD APPEAR TO CONTAIN
THE OVERALL-HIGHEST THREAT OF SEVERE STORMS DURING THE NEXT
SEVERAL DAYS...ALTHOUGH THE JURY IS STILL OUT ON WHETHER IT WOULD
BE MORE LOCALIZED OR MORE WIDESPREAD. CERTAINLY WOULD NOT BE
SURPRISED TO SEE THE UPCOMING SPC DAY 2 OUTLOOK INTRODUCE A SLIGHT
RISK FOR ALL/PART OF THE CWA...MAINLY FOR THE AFTERNOON/EVENING
HOURS. IN THE BIG PICTURE...SEASONABLY STRONG/SHARP NORTHWEST FLOW
STRENGTHENS AB IT...AS MODELS ARE IN DECENT AGREEMENT IN DRIVING A
BIT STRONGER/ORGANIZED SHORTWAVE TROUGH SOUTHWARD OUT OF WESTERN
SD ACROSS THE HEART OF CENTRAL NEB/KS. FOR THE MORNING
HOURS...KEPT POPS AT SLIGHT 20S EXCEPT 30S IN THE EAST WHERE
SEEMINGLY THE BEST CHANCE OF LINGERING OVERNIGHT CONVECTION WOULD
BE. THEN HAVE 30 POPS NEARLY ALL AREAS DURING THE AFTERNOON TO
ACCOUNT FOR THUNDERSTORM REDEVELOPMENT AND/OR
RE-INTENSIFICATION...ASSUMING OF COURSE THAT SUFFICIENT HEATING
CAN TAKE PLACE. ITS STILL TOO SOON TO TELL THOUGH WHETHER
POTENTIALLY VIGOROUS AFTERNOON ACTIVITY MAINLY DEVELOPS LOCALLY OR
MOVES IN FROM THE NORTHWEST. AT ANY RATE...THE 18Z NAM DEPICTS A
FAIRLY POTENT NORTHWEST FLOW SEVERE ENVIRONMENT WITH MIXED LAYER
CAPE 2000+ J/KG IN THE PRESENCE OF DECENT 30-40 KNOT DEEP LAYER
SHEAR...MAKING A FEW SUPERCELLS A POSSIBILITY IF THE MESOSCALE
FEATURES COME TOGETHER. FOR THURSDAY EVENING/NIGHT...KEPT 30-50
POPS GOING AREA-WIDE...HIGHEST IN THE FAR SOUTH. NOT ACCOUNTING
FOR POSSIBLE CONVECTIVE EFFECTS...BREEZES DURING THE DAY THURSDAY
ARE EXPECTED TO AVERAGE AROUND 10 MPH FROM THE SOUTH.
FRIDAY/FRIDAY NIGHT...THE LATEST NAM/GFS ARE IN GOOD AGREEMENT
AMPLIFYING THE WESTERN CONUS RIDGE EASTWARD OVER THE CENTRAL
PLAINS...RESULTING IN MODEST HEIGHT RISES AND NEARLY DUE-NORTHERLY
FLOW ALOFT. THIS SHOULD RESULT IN A LESS-FAVORABLE ENVIRONMENT FOR
THUNDERSTORM DEVELOPMENT. HOWEVER...KEPT THE MAJORITY OF THE CWA
WITH SLIGHT POPS DURING THE DAYTIME HOURS MAINLY TO ACCOUNT FOR
POSSIBLE DIURNAL-HEATING INDUCED CONVECTION...BUT LEFT FRIDAY
NIGHT DRY PER PREVIOUS FORECAST.
SATURDAY THROUGH SUNDAY...KEPT THE DRY FORECAST GOING CWA-
WIDE...AS SEEMINGLY-BENIGN NORTHERLY FLOW REMAINS IN PLACE ALOFT
TO THE EAST OF THE ROCKIES-CENTERED RIDGE AXIS. BOTH THE ECWMF/GFS
KEEP THE MAIN BRANCHES OF STRONGER FLOW ALOFT WELL NORTH NEAR THE
CANADIAN BORDER...AND ALSO IN THE SOUTHEAST STATES...WITH THE CWA
ALSO STAYING SAFELY NORTHWEST OF A STALLED...POSSIBLY RETROGRADING
CLOSED MID LEVEL LOW OVER THE SOUTHERN MO/AR AREA ADVERTISED MORE
SO BY THE ECMWF THAN THE GFS. NOT READY TO GUARANTEE A DRY WEEKEND
YET...BUT AT LEAST FOR NOW POPS HAVE BEEN KEPT IN THE SILENT 5-10
RANGE. GIVEN THAT THE AREA HAS SEEN VERY LITTLE IN THE WAY OF NON-
CONVECTIVE BREEZE LATELY...ITS WORTH NOTING THAT THE CURRENT
SUNDAY FORECAST ACTUALLY HAS SUSTAINED SOUTHERLY SPEEDS UP AROUND
15 MPH/GUSTS AROUND 20 MPH.
SUNDAY NIGHT THROUGH TUESDAY MARKS THE RETURN OF VARIOUS...LOW-
CONFIDENCE THUNDERSTORM CHANCES OF THE 20-30 PERCENT
VARIETY...THAT WILL UNDOUBTEDLY BE REFINED SEVERAL TIMES DURING
THE NEXT SEVERAL DAYS. FROM A GENERAL...SYNOPTIC SCALE
STANDPOINT...BOTH THE ECWMF/GFS BREAK DOWN THE RIDGE-DOMINATED
PATTERN FROM THE WEEKEND AND GRADUALLY BRINGS A QUASI-ZONAL
PATTERN AS ONE OR TWO FAIRLY LOW-AMPLITUDE SHORTWAVE TROUGHS OF
NOTE WORK INTO THE CENTRAL PLAINS FROM THE WEST. THIS SHOULD
SUPPORT A CONTINUED SURFACE PATTERN OF LIGHT BUT NOTICEABLY
SOUTHERLY BREEZES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 520 PM CDT TUE AUG 13 2013
THE MAIN CONCERN FOR THE TAF PERIOD IS THE POTENTIAL FOR FOG
TONIGHT...THEN TIMING OF THUNDERSTORMS ON WEDNESDAY. CONVECTION
REMAINS WELL WEST OF THE TERMINAL THIS EVENING AND GENERALLY
EXPECT THE DRY CONDITIONS TO PERSIST UNTIL WEDNESDAY AFTERNOON.
WITH WET GROUND AND DECREASING CLOUDS THIS EVENING...THERE IS SOME
POTENTIAL FOR FOG DEVELOPMENT AND MODELS ARE NOT IN COMPLETE ON
HOW DENSE FOG MAY BE AND HAVE JUST TRENDED WITH MVFR VSBYS TO
START. AN UPPER LEVEL DISTURBANCE WILL CROSS NEB ON WEDNESDAY CHCS
FOR TSTMS INCREASING AGAIN BY MID/LATE AFTN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
401 PM CDT TUE AUG 13 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
WE HAD A MESOSCALE CONVECTIVE VORTEX (MCV) TRACK ACROSS OUR FORECAST
AREA THIS MORNING INTO THE EARLY AFTERNOON HOURS. THIS BROUGHT
WIDESPREAD RAINFALL TO OUR FORECAST AREA AND HAS WORKED OVER THE
ATMOSPHERE ENOUGH THAT ADDITIONAL PRECIPITATION THIS EVENING INTO
TONIGHT IS UNLIKELY. THE CONVECTION THAT TRACKED THROUGH OUR AREA
HAS NOW PASSED SOUTH INTO CENTRAL KANSAS AND NEW STORMS HAVE ALSO
FORMED TO OUR WEST OVER THE HIGH PLAINS OF WESTERN NEBRASKA.
THE WESTERN NEBRASKA THUNDERSTORMS HAVE FORMED ALONG THE LEADING
EDGE OF THE NEXT SHORTWAVE THAT IS TRACKING SOUTHEAST FROM EASTERN
WYOMING/SOUTHWEST SOUTH DAKOTA INTO WESTERN NEBRASKA. DEEP MOISTURE
CONVERGENCE AND AFTERNOON DESTABILIZATION IS ALSO MAXIMIZED ACROSS
WESTERN NEBRASKA INTO THE BLACK HILLS AND THIS IS WHERE ADDITIONAL
THUNDERSTORMS ARE EXPECTED TO FORM THIS EVENING. THIS IS A WEAKLY
SHEARED ENVIRONMENT AND STORM PROPAGATION WILL GENERALLY BE A SLOW
DRIFT TO THE SOUTH...WHICH SHOULD KEEP THE WESTERN STORMS JUST TO
THE WEST OF OUR FORECAST AREA TONIGHT. THERE IS AN OUTSIDE CHANCE OF
OUR WESTERN ZONES SEEING A PREDAWN SHOWER/THUNDERSTORM SHOULD THE
BLACK HILLS CONVECTION MAKE IT THIS FAR SOUTHEAST. HOWEVER...MOST
FORECAST MODEL DATA KEEPS ALL CONVECTION WEST OF OUR FORECAST AREA
TONIGHT AND THUS WE WILL KEEP ALL ZONES DRY TONIGHT...WHILE KEEPING
AN EYE ON THE WEST FOR THE POSSIBILITY OF NEEDING TO THROW SOME POPS
IN THE FORECAST DEPENDING ON FUTURE RADAR TRENDS.
THERE IS SOME POTENTIAL OF FOG TONIGHT GIVEN THE RECENT WIDESPREAD
RAINFALL. HOWEVER...FORECAST MODELS ARE MIXED ON FOG POTENTIAL WITH
THE HRRR MORE FAVORABLE FOR FOG WHILE THE SREF WOULD NOT GIVE US ANY
FOG. ULTIMATELY FOG WILL LARGELY HINGE ON CLOUD COVER AND SUBSEQUENT
COOLING. HAVE LEFT FOG OUT OF THE FORECAST FOR NOW...BUT SHOULD WE
CLEAR OUT AND REMAIN CLEAR THROUGH MOST OF THE NIGHT...THEN COOLING
MIGHT BE ADEQUATE FOR SOME AREAS OF FOG EARLY WEDNESDAY MORNING.
WEDNESDAY...A SHORT WAVE TROUGH WILL TRACK SOUTHEAST ACROSS WESTERN
NEBRASKA. INSTABILITY AND DEEP LAYER SHEAR WILL BE FAIRLY WEAK TO
MODEST AT BEST AND THUS AM NOT EXPECTING SEVERE WEATHER...BUT CAN
NOT RULE OUT A COUPLE OF STRONG THUNDERSTORMS IN ASSOCIATION WITH
PEAK AFTERNOON HEATING. THE BEST CHANCE OF THUNDERSTORMS WILL BE
ACROSS OUR WESTERN ZONES AND TO THE WEST OF OUR FORECAST AREA IN
ASSOCIATION WITH THE APPROACHING SHORTWAVE. TEMPERATURES WILL REMAIN
COOL FOR AUGUST DUE TO A CONTINUATION OF THE COOL AIRMASS
OVERHEAD...CLOUDS...AND POSSIBLE PRECIPITATION. HIGHS WILL GENERALLY
BE IN THE UPPER 70S TO LOWER 80S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
THE MAIN HIGHLIGHTS OF THIS 6-DAY PERIOD ARE A CONTINUATION OF
CHALLENGING SHOWER/THUNDERSTORM CHANCES IN THE WED NIGHT THROUGH
FRIDAY TIME FRAME WHICH MIGHT EVEN FEATURE A STRONG-SEVERE STORM
THREAT CENTERED ON THURSDAY...FOLLOWED BY WHAT APPEARS TO BE A
PREDOMINANTLY DRY WEEKEND...AND THEN A RETURN TO VERY UNCERTAIN
RAIN CHANCES IN THE SUNDAY NIGHT-TUESDAY TIME FRAME AS THE PATTERN
CHANGES A BIT. ITS BEEN A TOUGH GO OF IT LATELY TRYING TO
DETERMINE HOW HARD TO HIT...OR BACK OFF...POPS EVEN IN THE FIRST
24 HOURS...SO THESE UNCERTAINTIES CONTINUE TO BE MAGNIFIED EVEN IN
THE DAY 2-3 TIME FRAME. OF HIGHER CONFIDENCE IS THAT A FAIRLY
REMARKABLE RUN OF SUB-90 DEGREE TEMPS WILL CONTINUE...WITH THE
MAJORITY OF THE CWA FORECAST TO TOP OUT IN THE LOW-MID 80S DURING
THIS TIME FRAME...WITH KS ZONES AS USUAL MOST FAVORED TO REACH
UPPER 80S ON A FEW DAYS. AS FOR LOW TEMPS...EVERY NIGHT IS
EXPECTED TO BE FAIRLY SIMILAR AND RATHER UNIFORM ACROSS THE
CWA...EITHER IN THE LOW OR MID 60S.
STARTING OFF WEDNESDAY EVENING/NIGHT...GAVE A BEST-STAB AT TWO
6-HOUR POP BLOCKS HEAVILY BASED ON MET/MAV GUIDANCE BLEND...WITH
THE EVENING PERIOD FEATURING 20S-40S...AND THE LATE NIGHT PERIOD
RANGING FROM ONLY 20S FAR WEST TO 50S IN EASTERN-MOST NEB ZONES.
IN OTHER WORDS...THERE IS A DECENT CHANCE THAT PARTS OF THE CWA
WILL SEE RAIN...BUT CONFIDENCE IN TIMING/PLACEMENT PRECLUDES
LIKELY POPS ANYWHERE YET. ON THE LARGE-SCALE ALOFT...LEGITIMATE
NORTHWEST-FLOW IS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN A
RIDGE AXIS EXTENDING NORTHWARD ACROSS THE ROCKIES FROM NORTHERN
MEXICO INTO SOUTHWEST CANADA...AND A BROAD TROUGH ANCHORED OVER
SOUTHEAST CANADA/THE NORTHEAST CONUS. ON A MORE LOCAL/REGIONAL
LEVEL...THE CWA IS PROGGED TO REMAIN UNDER/NEAR THE MAIN TRACK OF
LOW-AMPLITUDE SHORTWAVE TROUGHS RIPPLING THROUGH THE NORTHWEST
FLOW. STARTING OFF RIGHT AWAY WED EVENING AT 00Z/7PM...ITS
EXPECTED THAT AT LEAST A SMALL PART OF THE CWA SHOULD BE SEEING
ACTIVITY PERSISTING FROM THE LATE AFTERNOON HOURS...ALTHOUGH MODEL
QPF/REFLECTIVITY FIELDS VARY CONSIDERABLY ON THE MOST FAVORED
AREA. AS THE NIGHT WEARS ON...THERE IS A DECENT SIGNAL FOR WARM
AIR ADVECTION/MOISTURE TRANSPORT IN THE 850-700 MILLIBAR
LAYER...WITHIN THE AXIS OF A MODEST 20+KT SOUTHWESTERLY LOW LEVEL
JET. PER THE 12Z/18Z NAM AND LAST FEW SREF RUNS...THIS WOULD FAVOR
EASTERN ZONES FOR THE HIGHEST LATE NIGHT POPS...WHILE THE
ECWMF/GFS WOULD MORE-SO FAVOR CENTRAL/SOUTHWEST ZONES. AS FOR
THUNDERSTORM INTENSITY...ALTHOUGH NOT EXPECTING A WIDESPREAD
NOCTURNAL SEVERE THREAT...CERTAINLY A FEW STRONG TO MARGINALLY
SEVERE STORMS WITH MAINLY A HAIL/LOCALLY HEAVY RAIN THREAT CANNOT
BE RULED OUT GIVEN MUCAPE INCREASING TO AT LEAST 500-1000 J/KG IN
THE PRESENCE OF AROUND 25KT OF DEEP LAYER SHEAR.
THURSDAY/THURSDAY NIGHT...THIS 24 HOURS WOULD APPEAR TO CONTAIN
THE OVERALL-HIGHEST THREAT OF SEVERE STORMS DURING THE NEXT
SEVERAL DAYS...ALTHOUGH THE JURY IS STILL OUT ON WHETHER IT WOULD
BE MORE LOCALIZED OR MORE WIDESPREAD. CERTAINLY WOULD NOT BE
SURPRISED TO SEE THE UPCOMING SPC DAY 2 OUTLOOK INTRODUCE A SLIGHT
RISK FOR ALL/PART OF THE CWA...MAINLY FOR THE AFTERNOON/EVENING
HOURS. IN THE BIG PICTURE...SEASONABLY STRONG/SHARP NORTHWEST FLOW
STRENGTHENS AB IT...AS MODELS ARE IN DECENT AGREEMENT IN DRIVING A
BIT STRONGER/ORGANIZED SHORTWAVE TROUGH SOUTHWARD OUT OF WESTERN
SD ACROSS THE HEART OF CENTRAL NEB/KS. FOR THE MORNING
HOURS...KEPT POPS AT SLIGHT 20S EXCEPT 30S IN THE EAST WHERE
SEEMINGLY THE BEST CHANCE OF LINGERING OVERNIGHT CONVECTION WOULD
BE. THEN HAVE 30 POPS NEARLY ALL AREAS DURING THE AFTERNOON TO
ACCOUNT FOR THUNDERSTORM REDEVELOPMENT AND/OR
RE-INTENSIFICATION...ASSUMING OF COURSE THAT SUFFICIENT HEATING
CAN TAKE PLACE. ITS STILL TOO SOON TO TELL THOUGH WHETHER
POTENTIALLY VIGOROUS AFTERNOON ACTIVITY MAINLY DEVELOPS LOCALLY OR
MOVES IN FROM THE NORTHWEST. AT ANY RATE...THE 18Z NAM DEPICTS A
FAIRLY POTENT NORTHWEST FLOW SEVERE ENVIRONMENT WITH MIXED LAYER
CAPE 2000+ J/KG IN THE PRESENCE OF DECENT 30-40 KNOT DEEP LAYER
SHEAR...MAKING A FEW SUPERCELLS A POSSIBILITY IF THE MESOSCALE
FEATURES COME TOGETHER. FOR THURSDAY EVENING/NIGHT...KEPT 30-50
POPS GOING AREA-WIDE...HIGHEST IN THE FAR SOUTH. NOT ACCOUNTING
FOR POSSIBLE CONVECTIVE EFFECTS...BREEZES DURING THE DAY THURSDAY
ARE EXPECTED TO AVERAGE AROUND 10 MPH FROM THE SOUTH.
FRIDAY/FRIDAY NIGHT...THE LATEST NAM/GFS ARE IN GOOD AGREEMENT
AMPLIFYING THE WESTERN CONUS RIDGE EASTWARD OVER THE CENTRAL
PLAINS...RESULTING IN MODEST HEIGHT RISES AND NEARLY DUE-NORTHERLY
FLOW ALOFT. THIS SHOULD RESULT IN A LESS-FAVORABLE ENVIRONMENT FOR
THUNDERSTORM DEVELOPMENT. HOWEVER...KEPT THE MAJORITY OF THE CWA
WITH SLIGHT POPS DURING THE DAYTIME HOURS MAINLY TO ACCOUNT FOR
POSSIBLE DIURNAL-HEATING INDUCED CONVECTION...BUT LEFT FRIDAY
NIGHT DRY PER PREVIOUS FORECAST.
SATURDAY THROUGH SUNDAY...KEPT THE DRY FORECAST GOING CWA-
WIDE...AS SEEMINGLY-BENIGN NORTHERLY FLOW REMAINS IN PLACE ALOFT
TO THE EAST OF THE ROCKIES-CENTERED RIDGE AXIS. BOTH THE ECWMF/GFS
KEEP THE MAIN BRANCHES OF STRONGER FLOW ALOFT WELL NORTH NEAR THE
CANADIAN BORDER...AND ALSO IN THE SOUTHEAST STATES...WITH THE CWA
ALSO STAYING SAFELY NORTHWEST OF A STALLED...POSSIBLY RETROGRADING
CLOSED MID LEVEL LOW OVER THE SOUTHERN MO/AR AREA ADVERTISED MORE
SO BY THE ECMWF THAN THE GFS. NOT READY TO GUARANTEE A DRY WEEKEND
YET...BUT AT LEAST FOR NOW POPS HAVE BEEN KEPT IN THE SILENT 5-10
RANGE. GIVEN THAT THE AREA HAS SEEN VERY LITTLE IN THE WAY OF NON-
CONVECTIVE BREEZE LATELY...ITS WORTH NOTING THAT THE CURRENT
SUNDAY FORECAST ACTUALLY HAS SUSTAINED SOUTHERLY SPEEDS UP AROUND
15 MPH/GUSTS AROUND 20 MPH.
SUNDAY NIGHT THROUGH TUESDAY MARKS THE RETURN OF VARIOUS...LOW-
CONFIDENCE THUNDERSTORM CHANCES OF THE 20-30 PERCENT
VARIETY...THAT WILL UNDOUBTEDLY BE REFINED SEVERAL TIMES DURING
THE NEXT SEVERAL DAYS. FROM A GENERAL...SYNOPTIC SCALE
STANDPOINT...BOTH THE ECWMF/GFS BREAK DOWN THE RIDGE-DOMINATED
PATTERN FROM THE WEEKEND AND GRADUALLY BRINGS A QUASI-ZONAL
PATTERN AS ONE OR TWO FAIRLY LOW-AMPLITUDE SHORTWAVE TROUGHS OF
NOTE WORK INTO THE CENTRAL PLAINS FROM THE WEST. THIS SHOULD
SUPPORT A CONTINUED SURFACE PATTERN OF LIGHT BUT NOTICEABLY
SOUTHERLY BREEZES.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z WEDNESDAY
AFTERNOON) ISSUED AT 1245 PM CDT TUE AUG 13 2013
THE RAIN IS ON THE WAY OUT OF KGRI AND EXPECT VISIBILITY AND
CEILINGS WILL IMPROVE INTO VFR RANGE BETWEEN 18Z AND 19Z. DRY
WEATHER IS LIKELY THROUGH THE REMAINDER OF THE TAF PERIOD WITH
LIGHT WINDS. THE WIND DIRECTION WILL GENERALLY BE VARIABLE THROUGH
TONIGHT AND THEN SHOULD BECOME PREDOMINATELY SOUTHERLY BY EARLY
TOMORROW MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1241 AM CDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 1241 AM CDT TUE AUG 13 2013
LOW TEMPS WERE RAISED 2-3F WITH THIS ESTF UPDATE BASED ON CURRENT
AND EXPECTED CLOUD COVER. ALSO REMOVED POPS FOR THE NEXT 3 HRS. WE
ARE NOTING SHWRS WITH OCCASIONAL THUNDER DEVELOPING OVER SRN SD
DOWN INTO THE SANDHILLS. PER THE PREVIOUS SHIFTS EXPECTATION...
THESE SHWRS SHOULD ARRIVE INTO S-CNTRL NEB BEFORE DAWN AND COULD
COMPLICATE TOMORROW`S FCST. CLOUDS WERE ALSO INCREASED THRU
DAYBREAK.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
THE MAIN ISSUES DURING THE NEXT 24 HOURS INCLUDE FICKLE
THUNDERSTORM CHANCES...ALONG WITH WHETHER OR NOT FOG TONIGHT MIGHT
END UP BEING IMPACTFUL IN SOME SPOTS.
20Z OBJECTIVE SURFACE ANALYSIS SHOWS A WEAK COLD FRONT STRETCHED
ACROSS KS FROM SOUTHWEST-NORTHEAST...WHILE TO THE NORTH OF THIS
BOUNDARY...THE MAJORITY OF THE CWA IS EXPERIENCING LIGHT BREEZES
RANGING FROM NEAR-CALM TO NO MORE THAN 5-10 MPH FROM THE EAST-
NORTHEAST UNDER THE INFLUENCE OF BROAD HIGH PRESSURE EXTENDING
WELL SOUTHWARD FROM CANADA. ALOFT...WATER VAPOR IMAGERY AND SHORT
TERM MODEL DATA SHOWS GENERALLY WEST-NORTHWEST FLOW ALOFT OVER THE
CENTRAL PLAINS...MORE WESTERLY UP AROUND 300 MILLIBARS..AND MORE
NORTHERLY FARTHER DOWN IN THE MID LEVELS 500/700 MILLIBARS. THIS
FLOW REGIME REMAINS ESTABLISHED BETWEEN A LARGE SCALE TROUGH OVER
THE GREAT LAKES/SOUTHEAST CANADA AREA...AND A RIDGE EXTENDING
NORTH-NORTHWEST INTO THE ROCKIES OUT OF THE TX/NORTHERN MEXICO
AREA. IN TERMS OF THE REGIONAL SCALE...THE MAIN LOW AMPLITUDE
DISTURBANCE OF INTEREST HAS PASSED ONTO THE EAST INTO
MO...ALTHOUGH SMALL RIBBONS OF CHANNELED VORTICITY ARE EVIDENT
EXTENDING BACK WEST-NORTHWEST ACROSS THE SOUTHERN CWA TOWARD THE
WY/NE/CO BORDER AREA PER LATEST OBJECTIVE MESO-ANALYSIS.
DESPITE WHAT VARIOUS MODELS WERE EARLIER-SHOWING...THE CWA HAS
REMAINED DRY ALL DAY IN THE WAKE OF THE EXTENSIVE CONVECTION
SUNDAY EVENING/EARLY THIS MORNING. VISIBLE SATELLITE REVEALS ONLY
A SCATTERED TO LOCALLY BROKEN FAIR WEATHER CUMULUS FIELD MAINLY IN
THE FAR NORTHERN/EASTERN/SOUTHERN COUNTIES...AND HIGH TEMPERATURES
ARE ON TRACK TO TOP OUT 82-85 NEARLY ALL AREAS.
FOR LATE THIS AFTERNOON INTO THIS EVENING...MODELS CONTINUE TO
STRUGGLE WITH THEIR INDIVIDUAL QPF FIELDS...AS SOME APPEAR TO
THINK THAT CONVECTION WILL BREACH A WEAK CAP LOCALLY. LEANING
TOWARD THE HIGHER-RES SOLUTIONS OF THE HRRR AND 4KM WRF
NMM/ARW...IT APPEARS RATHER UNLIKELY THAT ANYTHING WILL POP IN THE
NEXT 3-6 HOURS ESPECIALLY ACROSS THE CENTRAL/EASTERN CWA DUE TO
LACK OF FORCING AND LACK OF LOW-LEVEL CONVERGENCE...AS THE WEAK
CAP SHOULD HOLD DESPITE THE PRESENCE OF 1000-1500 J/KG 0-1KM MIXED
LAYER CAPE PER LATEST RUC ANALYSIS. AS A RESULT...THROUGH MIDNIGHT
HAVE CONFINED SLIGHT POPS TO MAINLY THE WESTERN 1/4 TO 1/3 OF THE
CWA...MAINLY TO ACCOUNT FOR THE SMALL POSSIBILITY THAT STORMS
CURRENTLY DEVELOPING IN WESTERN NEB...AND MAYBE EVENTUALLY IN
NORTHWEST KS AS WELL...MIGHT SLIP EASTWARD INTO THE CWA. GIVEN THE
CONTINUED WEAK DEEP LAYER SHEAR REGIME ONLY AROUND 20KT...AND
INSTABILITY FADING WITH TIME TONIGHT...THINK THE PROBABILITY OF
STRONG THUNDERSTORMS...LET ALONE SEVERE...IS QUITE LOW. AFTER
MIDNIGHT...UNCERTAINTY CONTINUES TO GROW...BUT WITH BOTH THE
LATEST HRRR AND 18Z NAM ADVERTISING SOME CONVECTION FLARING UP
MAINLY JUST NORTHWEST OF THE CWA LIKELY IN RESPONSE TO SOME SUBTLE
MID LEVEL THETA-E ADVECTION...AND OTHER MODELS SHOWING CONVECTION
LURKING IN OR NEAR KS ZONES...WENT AHEAD AND EXPANDED 20-30 POPS
TO INCLUDE ALL BUT A HANDFUL OF SOUTHEASTERN COUNTIES JUST IN
CASE. THE OTHER POTENTIAL ISSUE TONIGHT IS FOG. WHILE MET/MAV
GUIDANCE IS SUGGESTING ONLY SOME LIGHT FOG...THE 15Z SREF SUGGESTS
PERHAPS AN ENHANCED RISK OF VISIBILITY RESTRICTIONS BELOW 1 MILE
ESPECIALLY ACROSS THE SOUTHWEST 1/3 OF THE CWA LATE TONIGHT.
CERTAINLY THE VERY LIGHT EASTERLY FLOW REGIME AND RECENT RAINFALL
COULD HELP THE CAUSE OF FOG FORMATION...BUT GIVEN THAT FOG DID NOT
BECOME TOO MUCH OF AN ISSUE LAST NIGHT IN THE WAKE OF DEPARTING
CONVECTION WITH A SIMILAR WIND REGIME...DECIDED TO ONLY INTRODUCE
A PATCHY FOG MENTION CWA-WIDE FOR NOW LATE TONIGHT...AND DEFER TO
NEXT FEW SHIFTS TO MONITOR THE SITUATION AND RAMP UP FOG POTENTIAL
IF NECESSARY.
TURNING TO THE TUESDAY DAYTIME HOURS...THE QUESTIONS JUST CONTINUE
TO ARISE. TAKING VARIOUS MODEL QPF FIELDS AT FACE VALUE...THERE
COULD BE QUITE A BIT OF ONGOING CONVECTION DURING THE
DAY...ESPECIALLY ACROSS THE WESTERN HALF OF THE CWA...POSSIBLY AS
A CONTINUATION OF OVERNIGHT ACTIVITY MOVING IN...OR LOCAL
DEVELOPMENT RAMPING UP WITH DAYTIME HEATING...AS THE THERMODYNAMIC
STRUCTURE OF THE ATMOSPHERE SHOULD REMAIN SIMILAR TO TODAY WITH
WEAK CAPPING IN THE PRESENCE OF ROUGHLY 1000 J/KG OF CAPE. THE
MILLION DOLLAR QUESTION IS WHETHER NOT FORCING WILL BE STRONG
ENOUGH TO REALIZE THE POTENTIALLY WIDESPREAD CONVECTION ADVERTISED
BY SOME MODELS...OR WHETHER MODELS ARE OVER-DOING QPF AS SEVERAL
DID FOR TODAY. THERE SHOULD AT LEAST BE A FEW SUBTLE SHORTWAVE
TROUGHS PASSING THROUGH THE REGION PER MODEL VORTICITY
FIELDS...PRIMARILY PASSING ACROSS THE SOUTHWEST 1/2 OF THE CWA AND
POINT SOUTH. FOR NOW...DECIDED TO MAKE LITTLE CHANGE TO PREVIOUS
FORECAST WHICH ALREADY HAD POPS LOW AT NO MORE THAN 20-30
PERCENT...WITH THESE CHANCES COVERING MOST OF THE CWA IN THE
MORNING...AND THE ENTIRE AREA IN THE AFTERNOON. IF FORCING IS IN
FACT ENOUGH TO GENERATE WIDESPREAD CONVECTION...THEN NEXT SHIFT
MAY HAVE TO RAISE POPS NOTICEABLY ESPECIALLY IN WESTERN
AREAS...BUT AFTER SEEING HOW TODAY ENDED UP BONE-DRY THROUGH LATE
AFTERNOON...THINK IT WOULD BE UNWISE TO GET CARRIED AWAY WITH RAIN
CHANCES EVEN 12-24 HOURS OUT. AGAIN...NOT EXPECTING ANY SEVERE
STORMS...BUT A LOCALIZED STRONG STORM PROBABLY NOT OUT OF THE
QUESTION. OBVIOUSLY HIGH TEMPERATURES WILL BE HIGHLY DEPENDENT ON
THE COVERAGE...OR LACK THEREOF...OF DAYTIME CONVECTION...SO THERE
IS SOME UNCERTAINTY HERE TOO. GIVEN A SIMILAR LOW-LEVEL TEMP
REGIME...BLENDED THE COOLER PREVIOUS FORECAST FOR TOMORROW WITH
READINGS SIMILAR TO THOSE OBSERVED TODAY...WHICH RESULTS IN A
SLIGHT INCREASE TO PREVIOUS HIGHS AND NOW CALLING FOR 79-82 MOST
AREAS. BREEZES DURING THE DAY SHOULD AVERAGE ONLY 5-10 MPH FROM
THE EAST ASSUMING CONVECTIVE OUTFLOW DOESN/T GET TOO INVOLVED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
HE COOLER THAN NORMAL TREND WILL LIKELY CONTINUE THROUGH AT LEAST
SATURDAY...WITH PERHAPS A RETURN OF NEAR NORMAL HIGHS BY SUNDAY AND
MONDAY. WEAK SHORT WAVES WILL TRACK ACROSS OUR FORECAST AREA WITHIN
THE PERSISTENT UPPER LEVEL NORTHWESTERLY FLOW REGIME.
CONSEQUENTLY...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE ACROSS AT LEAST PORTIONS OF OUR FORECAST AREA OFF AND ON
AGAIN THROUGH MUCH OF THE PERIOD.
TUESDAY NIGHT THROUGH WEDNESDAY...A DECENT 500 MB VORT MAX/SHORT
WAVE WILL TRACK SOUTHEAST ACROSS THE HIGH PLAINS BRINGING A CHANCE
OF THUNDERSTORMS PRIMARILY TO AREAS WEST OF OUR FORECAST AREA.
HOWEVER...THERE IS GENERALLY A SLIGHT CHANCE THAT A FEW OF THESE
THUNDERSTORMS COULD TRACK INTO OUR WESTERN ZONES PRIMARILY WEST OF
HWY 281. INSTABILITY AND SHEAR ARE BOTH WEAK AND THUS ANY
THUNDERSTORMS THAT WORK INTO OUR AREA WILL LIKELY BE NON SEVERE.
TEMPERATURES WILL BE COOL FOR THIS TIME OF YEAR WITH THE UPPER LEVEL
JET STREAM TO OUR SOUTH.
WEDNESDAY NIGHT THROUGH FRIDAY...THIS SHOULD BE OUR BEST CHANCE AT
MORE WIDESPREAD THUNDERSTORM POTENTIAL ACROSS THE FORECAST AREA AS
A TRAIN OF SUCCESSIVE SHORT WAVE TROUGHS WORK THEIR WAY ACROSS THE
CENTRAL PLAINS. UPPER LEVEL SHEAR AND INSTABILITY WILL ALSO BE ON
THE INCREASE ESPECIALLY THURSDAY AFTERNOON THROUGH FRIDAY...WHICH
MAY RESULT IN A FEW STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. AT
THIS POINT...IT DOES NOT APPEAR TO BE A WIDESPREAD SEVERE
EVENT...BUT CAN NOT RULE OUT THE POSSIBILITY OF ISOLATED SEVERE
STORMS. TEMPERATURES WILL REMAIN RELATIVELY COOL...UPPER 70S TO
AROUND 80 DUE TO CLOUDS...POTENTIAL PRECIPITATION...AND MEAN MID
AND UPPER LEVEL JET POSITION.
SATURDAY AND SUNDAY...A BIT OF AN UPPER RIDGE IS PREDICTED TO WORK
INTO OUR FORECAST AREA THAT IF IT VERIFIES WOULD RESULT IN DRY
CONDITIONS THIS WEEKEND AND THEN WARMING TEMPERATURES TO NEAR NORMAL
BY SUNDAY.
SUNDAY NIGHT AND MONDAY...THE NEXT UPPER SHORT WAVE IS PROJECTED BY
BOTH THE 12Z GFS AND 12Z ECMWF TO MOVE INTO THE CENTRAL PLAINS. THIS
WILL RESULT IN AT LEAST SOME CHANCE OF THUNDERSTORMS...PARTICULARLY
ACROSS OUR WEST...ALTHOUGH THESE CHANCES MAY EVENTUALLY NEED TO BE
EXPANDED/RAISED SHOULD CURRENT FAVORABLE MODEL TRENDS CONTINUE.
ALLBLEND GIVES US NEAR NORMAL TEMPERATURES...AND LIKELIHOOD IS THAT
WE WILL LIKELY BE NO WARMER THAN NORMAL...AND WOULD NOT BE SURPRISED
IF MONDAY HIGHS GET LOWERED SOME WITH FUTURE FORECAST UPDATES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1241 AM CDT TUE AUG 13 2013
REST OF TNGT: VFR THRU 10Z WITH OCCASIONAL CIGS AROUND 5K FT. THEN
SOME MVFR FOG IS POSSIBLE 11Z-12Z. LIGHT E WINDS.
TUE: VFR WITH SCT SHWRS AND POSSIBLE THUNDER. TIMING OF ANY PCPN
IS UNCERTAIN GIVEN ITS SCT NATURE. SO IT`S BEEN HANDLED WITH VCSH
FOR NOW. WATCH FOR POSSIBLE AMENDMENTS TO UPGRADE TO TSRA. ESE
WINDS LESS THAN 10 KTS.
TUE EVNG: VFR WITH SOME MISC DEBRIS CLOUDS AROUND 8K AND 25K FT.
WINDS WILL BECOME LIGHT AND VARIABLE.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: MEDIUM
WIND CONFIDENCE: HIGH
WX CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
749 PM EDT WED AUG 14 2013
.SYNOPSIS...
SCATTERED SHOWERS ASSOCIATED WITH AN UPPER TROUGH MOVING OVER THE
REGION WILL SUBSIDE LATER THIS EVENING...WITH A MOSTLY CLEAR AND
DRY NIGHT EXPECTED. A RIDGE OF HIGH PRESSURE WILL BUILD EAST INTO
THE NORTHEAST THURSDAY AND FRIDAY WITH MAINLY DRY WEATHER...THOUGH
A FEW ISOLATED SHOWERS ACROSS THE HIGHER TERRAIN WILL BE POSSIBLE.
WARMER TEMPERATURES AND A PROLONGED PERIOD OF FAIR AND DRY
CONDITIONS RETURNS TO THE NORTH COUNTRY THIS WEEKEND THROUGH EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 716 PM EDT WEDNESDAY...INHERITED FORECAST REMAINS IN GOOD
SHAPE THOUGH CONTINUED ISOLATED SHOWERS INTO THE MID EVENING HOURS
BASED ON RADAR TRENDS. GENERAL IDEA THAT THESE SHOWERS SHOULD
BEGIN TO DISSIPATE STILL LOOKS GOOD. HOWEVER...AN UPPER-LEVEL
SHORTWAVE TROUGH OVER NORTHERN ONTARIO IS PRODUCING A THICK DECK
OF LOW CLOUDS WHICH ARE DIVING SOUTHWARD FROM HUDSON BAY...WITH
ITS SOUTHERN EXTENT TO ROUGHLY PETAWAWA ONTARIO PER IR SATELLITE
IMAGERY. MOST RECENT SHORT- RANGE RH GUIDANCE SUCH AS THE 18Z NAM
AND 21Z RAP ALL SHOW THESE CLOUDS APPROACHING THE INTERNATIONAL
BORDER AROUND 05Z. IF TRENDS CONTINUE IT WOULD NECESSITATE SOME
UPWARD ADJUSTMENTS TO SKY COVER AND LOW TEMPERATURES..BUT FOR NOW
I WILL WAIT TO SEE HOW THESE TRENDS EVOLVE BEFORE MAKING THOSE
CHANGES WITH THE NEXT UPDATE. OTHERWISE HAVE JUST MATCHED WITH
CURRENT SFC OBSERVATIONAL DATA.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 334 PM EDT WEDNESDAY...FOR THE SHORT TERM PERIOD FROM
THURSDAY THROUGH FRIDAY NIGHT...SURFACE HIGH PRESSURE CONTINUES
TO BUILD INTO THE NORTHEAST AND MID-ATLANTIC STATES WHILE THE
AFOREMENTIONED UPPER TROUGH SLOWLY SHIFTS NORTHEAST INTO THE GULF
OF SAINT LAWRENCE. CONDITIONS ARE EXPECTED TO BE MAINLY DRY
ACROSS THE REGION THROUGH THE PERIOD...BUT ADDITIONAL SHORTWAVE
ENERGY ROUNDING THE BASE OF THE TROUGH GLANCING THE INTL BORDER
THURSDAY AND FRIDAY AFTERNOONS MAY PROVIDE A FEW ISOLATED TERRAIN
DRIVEN SHOWERS ACROSS NORTHERN VERMONT. OTHERWISE...GENERALLY
MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH TEMPS
REMAINING ON THE COOL SIDE OF NORMAL WITH HIGHS IN THE UPPER 60S
TO MID 70S...AND LOWS IN THE MID 40S TO LOWER 50S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 348 PM EDT WEDNESDAY...OVERALL TRANQUIL WEATHER EXPECTED
THROUGHOUT THE LONG TERM WITH NOT MUCH CHANGE IN MODEL GUIDANCE.
AT THE SFC...HIGH PRESSURE WILL DOMINATE THE NORTHEAST WITH FLAT
ZONAL FLOW ACROSS SOUTHERN CANADA. SOME DIURNAL CLOUDS MAINLY
OVER THE MTNS EXPECTED THROUGHOUT THE PERIOD AND GRADUAL WARMING
TREND AS THE SFC HIGH ANCHORS TO OUR EAST...ALLOWING FOR SLGT
S/SW FLOW OVER THE NORTH COUNTRY.
BEST CHANCE FOR SOME PRECIPITATION WILL BE TUESDAY AS AN UPPER
LEVEL TROUGH MOVES ACROSS SRN QUEBEC. MODELS DIVERGE ON TRACK AND
EVOLUTION OF THIS UPPER TROUGH...SO CONFIDENCE ON CHANCES FOR
PRECIP LOW THROUGH THE END OF THE PERIOD.
TEMPERATURES DURING THE DAY WILL REACH THE 70S-M80S...AND DIP
INTO THE M40S-L60S OVERNIGHT.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
THROUGH 18Z THURSDAY...MAINLY VFR COND EXPECTED THRU FORECAST
PERIOD. SCT-BKN050-120 FOR CEILINGS W/ VCSH THRU 02Z THURS...AND
AGAIN AFT 18Z THURS. SLK/MPV WILL SEE IFR TO VLIFR COND FROM
05Z-13Z DUE TO FG DEVELOPMENT AS WINDS ABATE. WINDS WILL VARY
MAINLY WSW-WNW 5-15KTS. LGT/VAR AT TIMES THOUGH AFT 05Z.
OUTLOOK 18Z THURSDAY THROUGH MONDAY...GENERALLY VFR CONDITIONS
UNDER HIGH PRESSURE WITH PERIODS OF VLIFR FOG/MIST EACH EVENING
AT KMPV AND KSLK.
&&
.MARINE...
AS OF 330 PM EDT WEDNESDAY...A LAKE WIND ADVISORY REMAINS IN
EFFECT THROUGH TONIGHT. GENERALLY WEST WINDS FROM 15 TO 25 KNOTS
CAN BE EXPECTED THIS EVENING AND OVERNIGHT. WINDS MAY BE VARIABLY
NORTHWEST THIS EVENING AND SOUTHWEST AFTER MIDNIGHT. CHOPPY WAVES
OF 1 TO 3 FEET CAN BE EXPECTED...ESPECIALLY ACROSS THE EASTERN
HALF OF THE LAKE. A FEW SCATTERED RAIN SHOWERS THIS EVENING WILL
TAPER OFF AND END BY SUNSET.
&&
.EQUIPMENT...
AS OF 435 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF/LOCONTO
SHORT TERM...LAHIFF
LONG TERM...KGM
AVIATION...KGM/JN
MARINE...MUCCILLI
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
716 PM EDT WED AUG 14 2013
.SYNOPSIS...
SCATTERED SHOWERS ASSOCIATED WITH AN UPPER TROUGH MOVING OVER THE
REGION WILL SUBSIDE LATER THIS EVENING...WITH A MOSTLY CLEAR AND
DRY NIGHT EXPECTED. A RIDGE OF HIGH PRESSURE WILL BUILD EAST INTO
THE NORTHEAST THURSDAY AND FRIDAY WITH MAINLY DRY WEATHER...THOUGH
A FEW ISOLATED SHOWERS ACROSS THE HIGHER TERRAIN WILL BE POSSIBLE.
WARMER TEMPERATURES AND A PROLONGED PERIOD OF FAIR AND DRY
CONDITIONS RETURNS TO THE NORTH COUNTRY THIS WEEKEND THROUGH EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 716 PM EDT WEDNESDAY...INHERITED FORECAST REMAINS IN GOOD
SHAPE THOUGH CONTINUED ISOLATED SHOWERS INTO THE MID EVENING HOURS
BASED ON RADAR TRENDS. GENERAL IDEA THAT THESE SHOWERS SHOULD
BEGIN TO DISSIPATE STILL LOOKS GOOD. HOWEVER...AN UPPER-LEVEL
SHORTWAVE TROUGH OVER NORTHERN ONTARIO IS PRODUCING A THICK DECK
OF LOW CLOUDS WHICH ARE DIVING SOUTHWARD FROM HUDSON BAY...WITH
ITS SOUTHERN EXTENT TO ROUGHLY PETAWAWA ONTARIO PER IR SATELLITE
IMAGERY. MOST RECENT SHORT- RANGE RH GUIDANCE SUCH AS THE 18Z NAM
AND 21Z RAP ALL SHOW THESE CLOUDS APPROACHING THE INTERNATIONAL
BORDER AROUND 05Z. IF TRENDS CONTINUE IT WOULD NECESSITATE SOME
UPWARD ADJUSTMENTS TO SKY COVER AND LOW TEMPERATURES..BUT FOR NOW
I WILL WAIT TO SEE HOW THESE TRENDS EVOLVE BEFORE MAKING THOSE
CHANGES WITH THE NEXT UPDATE. OTHERWISE HAVE JUST MATCHED WITH
CURRENT SFC OBSERVATIONAL DATA.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 334 PM EDT WEDNESDAY...FOR THE SHORT TERM PERIOD FROM
THURSDAY THROUGH FRIDAY NIGHT...SURFACE HIGH PRESSURE CONTINUES
TO BUILD INTO THE NORTHEAST AND MID-ATLANTIC STATES WHILE THE
AFOREMENTIONED UPPER TROUGH SLOWLY SHIFTS NORTHEAST INTO THE GULF
OF SAINT LAWRENCE. CONDITIONS ARE EXPECTED TO BE MAINLY DRY
ACROSS THE REGION THROUGH THE PERIOD...BUT ADDITIONAL SHORTWAVE
ENERGY ROUNDING THE BASE OF THE TROUGH GLANCING THE INTL BORDER
THURSDAY AND FRIDAY AFTERNOONS MAY PROVIDE A FEW ISOLATED TERRAIN
DRIVEN SHOWERS ACROSS NORTHERN VERMONT. OTHERWISE...GENERALLY
MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH TEMPS
REMAINING ON THE COOL SIDE OF NORMAL WITH HIGHS IN THE UPPER 60S
TO MID 70S...AND LOWS IN THE MID 40S TO LOWER 50S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 348 PM EDT WEDNESDAY...OVERALL TRANQUIL WEATHER EXPECTED
THROUGHOUT THE LONG TERM WITH NOT MUCH CHANGE IN MODEL GUIDANCE.
AT THE SFC...HIGH PRESSURE WILL DOMINATE THE NORTHEAST WITH FLAT
ZONAL FLOW ACROSS SOUTHERN CANADA. SOME DIURNAL CLOUDS MAINLY
OVER THE MTNS EXPECTED THROUGHOUT THE PERIOD AND GRADUAL WARMING
TREND AS THE SFC HIGH ANCHORS TO OUR EAST...ALLOWING FOR SLGT
S/SW FLOW OVER THE NORTH COUNTRY.
BEST CHANCE FOR SOME PRECIPITATION WILL BE TUESDAY AS AN UPPER
LEVEL TROUGH MOVES ACROSS SRN QUEBEC. MODELS DIVERGE ON TRACK AND
EVOLUTION OF THIS UPPER TROUGH...SO CONFIDENCE ON CHANCES FOR
PRECIP LOW THROUGH THE END OF THE PERIOD.
TEMPERATURES DURING THE DAY WILL REACH THE 70S-M80S...AND DIP
INTO THE M40S-L60S OVERNIGHT.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
THROUGH 18Z THURSDAY...VFR WITH SCT SHOWERS WILL CONTINUE TO
AFFECT THE NORTH COUNTRY PRODUCING PERIODS OF MVFR/IFR THIS AFTN.
SHOWERS MOST NUMEROUS OVER NRN NY AND NRN HALF OF VT. WITH LOSS
OF DAYTIME HEATING...GOING INTO THE EVENING HRS...SHOWERS WILL
DIMINISH AS WILL ACCOMPANYING CLOUD COVER. EXPECT GENERALLY
CLEARING SKIES OVERNIGHT...WITH MOISTURE FROM TODAY`S SHOWERS TO
PRODUCE SOME MVFR/IFR BR/FG AFTER MIDNIGHT...MAINLY AT KMPV/KSLK
AND KPBG. NW-N WINDS...OCCASIONALLY GUSTY THIS AFTN WILL DIMINISH
TO LIGHT TO CALM CONDITIONS AFTER SUNSET. AFTER 12Z...TAF SITES
WILL RECOVER TO VFR WITH INCREASING WINDS OUT OF THE S-SW AT
7-14KTS. MID LVL CLOUDS WILL ALSO INCREASE...WITH SOME DIURNAL
LOW CLOUDS DEVELOPING IN THE LATE MORNING.
OUTLOOK 18Z THURSDAY THROUGH MONDAY...GENERALLY VFR CONDITIONS
UNDER HIGH PRESSURE WITH PERIODS OF VLIFR FOG/MIST EACH EVENING
AT KMPV AND KSLK.
&&
.MARINE...
AS OF 330 PM EDT WEDNESDAY...A LAKE WIND ADVISORY REMAINS IN
EFFECT THROUGH TONIGHT. GENERALLY WEST WINDS FROM 15 TO 25 KNOTS
CAN BE EXPECTED THIS EVENING AND OVERNIGHT. WINDS MAY BE VARIABLY
NORTHWEST THIS EVENING AND SOUTHWEST AFTER MIDNIGHT. CHOPPY WAVES
OF 1 TO 3 FEET CAN BE EXPECTED...ESPECIALLY ACROSS THE EASTERN
HALF OF THE LAKE. A FEW SCATTERED RAIN SHOWERS THIS EVENING WILL
TAPER OFF AND END BY SUNSET.
&&
.EQUIPMENT...
AS OF 435 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF/LOCONTO
SHORT TERM...LAHIFF
LONG TERM...KGM
AVIATION...KGM/NEILES
MARINE...MUCCILLI
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
150 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TONIGHT AND PASS THROUGH THE
REGION ON TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. FAIR
AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY MODERATING
TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
900 PM EDT UPDATE...
ISOLATED LIGHT RAIN SHOWERS HAS DEVELOPED ACROSS THE REGION TONIGHT
WHERE WAA AND THETA-E ADVECTION IS TAKING PLACE AHEAD OF AN
APPROACHING UPPR LOW. VORT MAXES ARE BEING EJECTED FROM THE BASE OF
THE TROUGH AND ARE MOVING WITHIN THE CYCLONIC FLOW OVER THE
REGION...THUS EXPECT THESE SHOWERS TO CONTINUE AHEAD OF THE FROPA.
AS THE WAA CONTINUES OVERNIGHT...EXPECT SHOWERS TO BECOME MORE
SCATTERED LIKE IN NATURE.
SKY COVERAGE HAS INCREASED OVER THE REGION THUS DO NOT BELIEVE
THAT TEMPS WILL FALL MUCH FURTHER TONIGHT AS DENSE COVERAGE WILL
INHIBIT HEAT LOSS.
PREVIOUS FORECAST HOLDS GOOD AS FROPA IS EXPECTED TO MOVE THROUGH
TUESDAY MORNING.
PREVIOUS FORECAST...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
06Z UPDATE...
AN AREA OF RAIN WITH EMBEDDED THUNDER CONTINUES TO MARCH ACROSS
WESTERN NY AHEAD OF A COLD FRONT. EXPECT RAIN TO ARRIVE AT ALL
TERMINALS BETWEEN 07Z AND 11Z. BASED ON OBS TO OUR WEST AND A
MOISTURE LADEN ATMOSPHERE...IFR VSBYS ARE LIKELY FOR A 3 TO 4 HOUR
PERIOD THIS MORNING DUE TO MODERATE/HEAVY RAIN. INCLUDED A TEMPO
GROUP TO COVER THIS ROUGHLY IN THE 08Z TO 14Z TIME FRAME. FOR NOW
I LEFT OUT ANY MENTION OF THUNDER IN THE TAFS WITH WEAKER LAPSE
RATES ACROSS OUR AREA. WITH THE 09Z UPDATE I MAY HAVE TO ADD IN
THUNDER CHANCES IF LIGHTNING STRIKES REMAIN IMPRESSIVE.
ONCE THE INITIAL AREA OF RAIN MOVES TO THE EAST...NOTHING
WIDESPREAD ENOUGH IS EXPECTED TO OCCUR TO INCLUDE IN THE TAFS.
MVFR CIGS ARE POSSIBLE FOR A FEW HOURS BEFORE VFR RETURNS LATER
THIS AFTERNOON.
SOUTHWEST WINDS WILL SHIFT AROUND TO THE NW AFTER FRONT PASSES
THIS AFTERNOON. GENERALLY WINDS WILL BE 5 TO 10 KTS BUT WE MAY SEE
A FEW GUSTS ABOVE 10 KTS BEHIND THE FRONT THIS AFTERNOON.
OUTLOOK...
TUE NGT...A PD OF MVFR CIGS PSBL...SPCLY ACRS CNY.
WED THRU SAT...MAINLY VFR. THE ONLY EXCEPTION WILL BE PSBL EARLY
AM VLY FOG AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...KAH
SHORT TERM...
LONG TERM...CMG/MLJ
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
327 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AHEAD OF A COLD FRONT THAT WILL TRACK SLOWLY THROUGH CENTRAL NORTH
CAROLINA TONIGHT...A LEE SURFACE TROUGH WILL SHARPEN IN THE LEE OF
THE APPALACHIANS THIS AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE
MIDDLE ATLANTIC REGION...WHILE THE FRONT STALLS AND BECOMES
QUASI-STATIONARY ALONG THE CAROLINA COAST...MID TO LATE WEEK
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 325 PM TUESDAY...
THE NORTHWEST FRINGE OF AN AREA OF SCATTERED SHOWERS AND
STORMS...FROM NEAR KVUJ TO KRDU TO KIXA...ROUGHLY CORRESPONDED AT
19Z TO A DIFFERENTIAL HEATING BOUNDARY ALONG AN EARLIER MID LEVEL
CLOUD SHIELD ASSOCIATED WITH A LEAD IMPULSE STRETCHING FROM SE VA TO
THE SC UPSTATE. MEANWHILE...A SECOND AREA OF SHOWERS AND STORMS
CONTINUED TO BECOME BETTER ORGANIZED ALONG A LEE SURFACE TROUGH/
CONVERGENCE AXIS OVER WESTERN NC AND SW VA...AND IN ADVANCE OF A
STRONGER MID LEVEL IMPULSE ROUGHLY ALIGNED ALONG THE CENTRAL-
SOUTHERN APPALACHIANS. THE HRRR SUGGESTS THIS LATTER ACTIVITY WILL
WEAKEN...BUT THIS SEEMS TO BE IN ERROR SINCE THE AGGREGATE COLD POOL
HAS BECOME INCREASINGLY ORGANIZED AS IT PROPAGATES INTO AN
INCREASINGLY UNSTABLE AIR MASS WITH TIME AND EASTWARD EXTENT
DOWNSTREAM OVER CENTRAL NC. AS SUCH...THE MOST LIKELY SCENARIO IS
THAT SCATTERED MAINLY MULTI-CELLULAR ACTIVITY WILL CONTINUE TO
PERCOLATE OVER CENTRAL NC BEFORE THE AFOREMENTIONED WESTERN NC LINE
IMPACTS A LARGER PERCENTAGE OF THE POPULATION AS IT CONTINUES
SOUTHEASTWARD THROUGH THE EVENING HOURS.
WHILE MULTI-CELL CLUSTERS SHOULD BE THE DOMINANT CONVECTIVE MODE
WITH AN ASSOCIATED PRIMARY THREAT OF MARGINALLY SEVERE WIND
GUSTS...SEASONABLY STRONG MID LEVEL FLOW ON THE ORDER OF 30-40 KTS
(STRONGEST NORTH) PER 12Z RAOB AND MORE RECENT REGIONAL VWP
DATA...WILL ALSO SUPPORT AT LEAST TRANSIENT SUPERCELLS...
PARTICULARLY OVER THE NORTHERN COASTAL PLAIN AND NORTHEAST
PIEDMONT...WHERE BOTH BUOYANCY AND BULK SHEAR WILL BE RELATIVELY
MAXIMIZED. SEVERE WIND...AS WELL AS HAIL OWING TO DYNAMIC PRESSURE
EFFECTS...WOULD BE ENHANCED WITH ANY SUCH SUPERCELLULAR MODE.
RELATIVELY LONG AND STRAIGHT CURRENT AND FORECAST HODOGRAPHS SUGGEST
A FEW STORM SPLITS WILL BE PROBABLE...WITH AN OTHERWISE WSW MEAN
WIND VECTOR/STORM MOTION.
SCATTERED TO NUMEROUS SHOWER AND STORM COVERAGE SHOULD DIMINISH FROM
WEST TO EAST THROUGH MIDNIGHT. HOWEVER...A FEW WIDELY SCATTERED
SHOWERS AND ISOLATED STORMS WILL BE POSSIBLE ALONG THE SYNOPTIC COLD
FRONT - ONE STILL WELL WEST OF OUR REGION OVER THE EASTERN TN VALLEY
AT 16Z - AS IT PASSES SLOWLY THROUGH OUR REGION OVERNIGHT. THERE MAY
EVEN BE A LITTLE ANAFRONTAL LIGHT RAIN TOWARD THE FAR SOUTHEAST
REACHES OF THE CWFA AROUND DAYBREAK...AS THE MID-UPPER TROUGH AXIS
SHARPENS OVERHEAD. SINCE NWP GUIDANCE IS TYPICALLY TOO
FAST/AGGRESSIVE WITH FRONTAL PASSAGES...ESPECIALLY THIS TIME OF
YEAR...A CONTINUED VERY HUMID BOUNDARY LAYER OVER AT LEAST THE
EASTERN THIRD OF THE CWFA FOR MUCH OF THE NIGHT WILL SUPPORT AREAS
OF STRATUS AND FOG...PARTICULARLY IF MID LEVEL CLOUDINESS CLEARS
SUFFICIENTLY IN THE WAKE OF THE EARLIER CONVECTION. LOWS IN THE
UPPER 60S TO MIDDLE 70S.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 PM TUESDAY...
THOUGH THE LOW LEVEL FRONTAL ZONE AND ASSOCIATED CHANCE OF SHOWERS
AND STORMS SHOULD HAVE MOVED TO SOUTHEASTERN NC BY EARLY WED...NWP
CROSS SECTIONS SUGGEST POST-FRONTAL HIGH-BASED STRATOCUMULUS WILL
MAINTAIN MOSTLY CLOUDY CONDITIONS GENERALLY EAST OF I-95 THROUGH
MIDDAY...WITH CONSIDERABLE CIRRUS LINGERING THROUGHOUT THE
AFTERNOON. PARTLY TO MOSTLY SUNNY CONDITIONS SHOULD RULE ELSEWHERE.
SURFACE HIGH PRESSURE AND ASSOCIATED NORTH NORTHEASTERLY LOW LEVEL
FLOW...WHICH WILL GUST TO NEAR 20 MPH IN THE I-95 CORRIDOR
LATE-MORNING TO EARLY AFTERNOON...WILL RESULT IN MILDER CONDITIONS
AND MUCH LOWER HUMIDITY VALUES AS SURFACE DEWPOINTS DIP INTO THE 50S
ACROSS THE PIEDMONT - HIGH TEMPERATURES RANGING FROM THE UPPER 70S
TO NEAR 80 OVER THE NORTHERN COASTAL PLAIN...TO LOW-MID 80S SOUTHERN
PIEDMONT AND WESTERN SANDHILLS. LINGERING BUT THINNING CIRRUS
OVERNIGHT...WITH LOWS 60 TO 65 DEGREES...EXCEPT 55 TO 60 IN RURAL
PIEDMONT LOCATIONS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 230 PM TUESDAY...
THE MODELS STILL SHOW SOME VARIABILITY AS TO WHERE THE COLD FRONT
WILL STALL. THE GFS BRINGS THE FRONT ALMOST COMPLETELY THROUGH NC...
KEEPING THE REGION DRIER THAN OTHER MODELS FOR THE REST OF THE WEEK.
THE ECMWF DOES NOT PUSH THE FRONT AS FAR SUGGESTING THAT
THE SOUTHERN AND EASTERN PORTION OF NC COULD SEE A MUCH HIGHER QPF.
AS POINTED TO IN PREVIOUS DISCUSSIONS... HIGH SURFACE PRESSURE IN
THE NORTHEAST COULD ALLOW FOR A WARM SEASON CAD TO FORM IN THE LEE
OF THE APPALACHIANS WITH A WEDGE FRONT DRAPED ACROSS CENTRAL NC LATE
IN THE WEEK. HOW FAR THE FRONT WILL PROPAGATE REMAINS A TOPIC OF
DISCUSSION AS THE GFS PUSHES THIS FRONT ALL THE WAY THROUGH NC WITH
THE ECMWF DEPICTING A SHARPER...POSSIBLY MORE REALISTIC...BOUNDARY
SETTING UP JUST EAST OF THE FOOTHILLS AND ACROSS THE WESTERN
PIEDMONT. LOW PRESSURE IN THE GULF SHOULD ALSO BRING HIGH THETA-E
PARCELS UP THE EAST COAST CREATING VERY MOIST CONDITIONS FOR THE
WEEKEND.
THE FRONT WILL BEGIN TO STALL OVER EASTERN NC ON THURSDAY. MODEL
UNCERTAINTY IN THE EXACT LOCATION OF WHERE THE FRONT WILL STALL WILL
AFFECT QPF AMOUNTS WITH THE GFS CONFINING PRECIP TO THE COAST
WHEREAS THE ECMWF SETS UP THE FRONT CLOSER TO THE I-95 CORRIDOR.
CLIMATOLOGY AND NORMAL DIURNAL PROCESSES WOULD SUGGEST THAT THE
ECMWF SOLUTION WOULD BE FAVORED AT THIS TIME AND AT LEAST SOME QPF
WOULD BE REALIZED EAST OF I-95.
AS CAD CONDITIONS LOCK IN ON FRIDAY AND SATURDAY...SEVERAL SHORTWAVE
IMPULSES WILL TRAIN UP THE SOUTHEAST COAST PROVIDING BETTER DYNAMICS
FOR HEAVIER RAINFALL...AT LEAST FROM THE TRIANGLE EASTWARD...WITH
MORE OVERRUNNING PRECIP IN THE NORTHWEST DUE TO ISENTROPIC LIFT. IF
THE WEDGE FRONT IS PINNED BACK FARTHER TO THE WEST...THEN THE
POSSIBILITY FOR SEVERE STORMS IN THE EASTERN PORTION OF THE CWA
BECOMES GREATER BUT MODELS ARE STARTING TO DOWNPLAY THIS SCENARIO
AND SHOW MORE OF A NORTHEASTERLY FLOW REGIME FOR MOST OF THE AREA
WITH LITTLE LOW-LEVEL SHEAR OR HELICITY AVAILABLE THROUGH SUNDAY
MORNING. THIS STARTS TO CHANGE A BIT ON SUNDAY AFTERNOON AS AT LEAST
KFAY AND KRWI BEGIN TO SWITCH BACK TO A SOUTHERLY FLOW REGIME. MODEL
FORECAST SOUNDINGS SHOW THAT BY THE TIME DESTABILIZATION OCCURS BOTH
SITES COULD HAVE SOUTHWESTERLY FLOW KEEPING BULK SHEER (PRIMARILY
SPEED SHEER) DOWN TO 20 KNOTS OR SO WITH CLOSE TO 1000 J/KG OF
INSTABILITY. WHILE HEAVY RAIN AND FLOODING WOULD BE THE PRIMARY
THREAT...SMALL INVERTED-V SIGNATURES SUGGEST THAT WINDS COULD BE A
POSSIBLE SECONDARY THREAT. AS AN ASIDE THE NHC IS STILL NOT BUYING
INTO THE TROPICAL SYSTEM THAT THE GFS IS SPINNING UP IN THE NORTHERN
GULF ON FRIDAY EVENING DUE TO UNFAVORABLE UPPER LEVEL CONDITIONS.
THAT BEING SAID A ECMWF SOLUTION OF A MORE CONSTANT FLOW OF MOISTURE
OUT OF THE GULF IS MORE LIKELY WITH SMALLER SHORTWAVE IMPULSES
ENHANCING THE FLOW.
THE PRESENCE OF THE SAME MOIST AIR MASS WILL CONTINUE TO PRODUCE
UNSETTLED CONDITIONS WITH MORE PRECIPITATION INTO EARLY NEXT WEEK
ALTHOUGH THERE IS A FAIR AMOUNT OF MODEL UNCERTAINTY AT THE END OF
THE LONG TERM DEPENDING ON HOW EVENTS UNFOLD THIS WEEKEND. WILL KEEP
AT LEAST CHANCE POPS THROUGH THE END OF THE PERIOD.
TEMPERATURES IN THE LOW TO MID 80S ON WEDNESDAY SHOULD DROP IN TO
THE UPPER 70S FOR MUCH OF THE PERIOD DUE TO THE FRONTAL PASSAGE AND
POTENTIAL CAD. THICKNESS VALUES AS LOW AS 1370 IN THE TRIAD ARE
VALUES TYPICALLY SEEN IN EARLY MAY AS OPPOSED TO THE MIDDLE OF
AUGUST. HIGH DEWPOINTS SHOULD ALLOW FOR THE MIN TEMP TO REMAIN
AROUND NORMAL IN THE MID 60S. A WARMING TREND SHOULD ALLOW FOR MAX
TEMPS TO REACH THE UPPER 80S AND MIN TEMPS IN TO THE UPPER 60S BY
THE END OF THE PERIOD...WITH HIGHEST TEMPS IN THE SE AND REMAINING
COOLER IN THE NORTHWEST PIEDMONT.
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 220 PM TUESDAY...
SCATTERED SHOWERS AND STORMS THIS AFTERNOON WILL BECOME MORE
NUMEROUS...LIKELY IN THE FORM OF A BROKEN LINE THAT WAS DEVELOPING
OVER NW NC AND SW VA AS OF 18Z. THESE SHOWERS AND STORMS - AND
ASSOCIATED SUB-VFR CONDITIONS AND GUSTY WINDS - ARE LIKELY TO
IMPACT...FROM NORTHWEST TO SOUTHEAST...THE TRIAD TERMINALS TO KRDU
AND KRWI BETWEEN 20Z AND 02Z. THERE WILL REMAIN A LINGERING CHANCE
OF A SHOWER OR STORM UNTIL A COLD FRONT SLOWLY CROSSES OUR REGION
TONIGHT. IN ADDITION...AREAS OF FOG OR LOW STRATUS WILL BE
PROBABLE...MAINLY AT EASTERN TERMINALS...WHERE THE FRONTAL PASSAGE
WILL LIKELY BE DELAYED UNTIL AROUND SUNRISE. SOUTHWEST WINDS AHEAD
OF THE FRONT WILL VEER TO NORTHWESTERLY...THEN NORTH NORTHEASTERLY
WITH GUSTS OF 15-20 KTS...LATE MORNING TO EARLY AFTERNOON WED.
LOOKING AHEAD: A WAVE OF LOW PRESSURE WILL DEVELOP ALONG A FRONTAL
ZONE STALLED ALONG THE SOUTHEAST US COAST...AND RESULT IN A CHANCE
OF SUB-VFR CONDITIONS AND RAIN LATE WEEK-EARLY THIS WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...ELLIS/CR
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
303 PM EDT TUE AUG 13 2013
.SYNOPSIS...
A FRONT WILL APPROACH THE AREA TONIGHT AND MOVE THROUGH EASTERN
NORTH CAROLINA AROUND SUNRISE WEDNESDAY. FRONT WILL STALL ALONG
THE COAST THROUGH THE REMAINDER OF THE WEEK AND THE WEEKEND AS
WAVES OF LOW PRESSURES MOVE ALONG IT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 152 PM TUE...MODELS IN DECENT AGREEMENT ON TIMING OF
APPROACHING FRONT WITH NAM BEING A COUPLE OF HOURS SLOWER IN
BRINGING FRONT THROUGH EASTERN NORTH CAROLINA. HRRR HAS GOOD HANDLE
ON DEVELOPING ACTIVITY THIS AFTERNOON (RUC AND WRF NOT SHOWING ANY
PRECIP FOR THE NEXT FEW HOURS)...AND INDICATES AN INCREASE IN
COVERAGE AFTER SUNSET. BROAD UPPER TROUGH OVER THE EAST WITH A
SERIES OF WEAK MID-LEVEL PIECES OF ENERGY ROTATING AROUND IT WILL
KEEP THE FORECAST PERIOD UNSETTLED. FORECAST SOUNDINGS SHOWING
CAPES INCREASING OVERNIGHT FROM 2K TO AROUND 3.5K WITH LIS AROUND
-5 AND PWS OVER 2 INCHES. WILL HAVE A CONTINUING CHANCE OF
THUNDERSTORMS OVER NIGHT...SOME OF WHICH COULD HAVE HEAVY RAIN
WITH LOCALIZED FLOODING IN THE MODERATE MID LEVEL LAYER FLOW AND
HIGH PWS. FRONT WILL ENTER THE COASTAL PLAINS BEFORE SUNRISE.
&&
.SHORT TERM /WEDNESDAY/...
AS OF 155 PM TUE...FRONT WILL MOVE THROUGH THE COASTAL AREAS AROUND
MID MORNING. DRIER COOLER ATMOSPHERE WILL MOVE OVER THE AREA WITH
HIGH TEMPERATURES IN THE LOWER TO MIDDLE 80S IN THE NORTHERLY
FLOW...AND A DECREASE IN CLOUD COVER.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AS OF 3 PM TUE...BELOW NORMAL TEMPS AND ABOVE NORMAL PRECIP
EXPECTED THROUGH THE PERIOD. A FRONT WILL STALL OFF THE NC COAST
WED NIGHT THROUGH THE WEEKEND WITH AREAS OF LOW PRESSURE MOVING
ALONG THE BOUNDARY...AND SFC HIGH PRESSURE BUILDING NORTH OF THE
AREA. ONLY SIG CHANGE TO PREVIOUS FORECAST WAS TO TRIM POPS BACK
SLIGHTLY...WITH MODELS NOW COMING IN QUITE A BIT DRIER WED NIGHT
INTO FRI...ESP FOR AREAS IN THE NORTHERN TIER. COULD SEE A SHARP
PRECIP GRADIENT SET UP WED NIGHT THROUGH FRI...WHERE BEST PRECIP
CHANCES WILL BE ALONG THE COAST AND SOUTHERN TIER. FRONT WILL
LIKELY MOVE CLOSER TO THE COAST FRI INTO THE WEEKEND WITH WEAK
WAVES MOVING ALONG IT. WILL CONTINUE HIGH CHANCE POPS THIS
WEEKEND. LOW LEVEL THICKNESS VALUES...NELY FLOW AND ABUNDANT CLOUD
COVER AND PRECIP SUPPORT HIGH TEMPS IN THE UPPER 70S TO LOWER 80S
THROUGH THE WEEKEND...WITH OVERNIGHT LOWS IN THE MID 60S/LOWER
70S. MODEL DIFFERENCES CONTINUE EARLY NEXT WEEK BTWN
GFS/ECMWF...BUT AT THIS TIME IT LOOKS LIKE SLY FLOW WILL
RETURN...WITH TEMPS SLOWLY WARMING AS UPPER RIDGE BEGINS TO
REBUILD OVER THE SE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH 18Z WEDNESDAY/...
AS OF 1245 PM TUE...SHOWERS AND THUNDERSTORMS HAVE FORMED OVER
EASTERN NORTH CAROLINA THIS AFTERNOON...AND COVERAGE IS EXPECTED
TO INCREASE THROUGH THE DAY. WILL HAVE MVFR WITH OCCASIONAL IFR IN
CIG AND VIS WITH THESE STORMS. BROKEN LINE OF STORMS AHEAD OF
APPROACHING FRONT IS EXPECTED TO MOVE THROUGH THE AREA AFTER
SUNSET. DECREASED COVERAGE AFTER MIDNIGHT BUT WILL HAVE SOME
STRATUS FORMING. FRONTAL PASSAGE EXPECTED AROUND SUNRISE WITH WIND
SHIFTING TO NORTH NORTHEASTERLY.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 3 PM TUE...FRONT WILL STALL OFF THE NC COAST WED NIGHT
THROUGH LATE WEEK WITH AREAS OF LOW PRESSURE MOVING ALONG IT.
PERIODS OF SUB-VFR CONDITIONS LIKELY WED NIGHT THROUGH THE WEEKEND
WITH PRED NELY FLOW AND GOOD MOISTURE. SCT SHOWERS AND ISO TSTMS
EXPECTED EACH DAY.
&&
.MARINE...
SHORT TERM /THROUGH WEDNESDAY/...
AS OF 159 PM TUE...SOUTHWEST FLOW WILL INCREASE TO AROUND 20 KNOTS
THIS EVENING AS GRADIENT INCREASES IN ADVANCE OF APPROACHING FRONT.
MAY SEE SOME GUSTS TO 25 KNOTS AND SEAS COULD REACH 6 FEET IN THE
CENTRAL OUTER WATERS. THEREFORE WILL KEEP SCA UP. STRONG STORMS ARE
POSSIBLE THROUGH MUCH OF THE NIGHT WITH GUSTY WINDS AND HEAVY RAIN.
FRONT EXPECTED TO MOVE THROUGH THE WATERS DURING THE MORNING
WEDNESDAY WITH WIND SHIFTING TO NORTH NORTHEASTERLY AND DIMINISHING
IN SPEED TO AROUND 15 KNOTS. SEAS WILL DROP TO 3 TO 4 FEET WEDNESDAY.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 3 PM TUE...FRONT WILL STALL OFF THE NC COAST WED NIGHT
THROUGH THE WEEKEND WITH WAVES OF LOW PRESSURE MOVING ALONG IT.
A PERIOD OF MODERATE NE FLOW 10-20KT IS EXPECTED TO CONTINUE WED
NIGHT INTO THU NIGHT WITH SEAS UP TO 5FT...THEN DIMINISH TO
10-15KT FRI WITH SEAS 2-4FT. CONFIDENCE IS LOW REGARDING WIND
DIRECTIONS FOR THIS WEEKEND...AS MODELS CONTINUE TO DIFFER
HANDLING EXACT PLACEMENT OF FRONT IN COASTAL WATERS. THOUGH EXPECT
WINDS AOB 15KT THIS WEEKEND WITH SEAS 2-3FT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR AMZ152-154.
&&
$$
SYNOPSIS...CGG/CQD
NEAR TERM...CGG
SHORT TERM...CGG
LONG TERM...CQD
AVIATION...CGG/CQD
MARINE...CGG/CQD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
323 AM EDT TUE AUG 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN ACROSS THE REGION TODAY BEHIND A
DEPARTING COLD FRONT. FAIR WEATHER WITH BELOW NORMAL TEMPERATURES
AND PARTLY CLOUDY SKIES ARE EXPECTED FOR THE REMAINDER OF THE WORK
WEEK. THE HIGH WILL WEAKEN OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE FRONTAL PRECIPITATION ACROSS THE OHIO RIVER WILL GRADUALLY
SHIFT SOUTHEASTWARD THIS MORNING. COLD FRONT CURRENTLY LOCATED
ALONG AN INDIANAPOLIS TO LIMA LINE WILL CONTINUE ITS PROGRESSION
SOUTHEASTWARD THIS MORNING. BY THE LATE MORNING THIS FRONT IS
EXPECTED TO HAVE CLEARED ALL OF OUR ZONES. ANY LINGERING
PRECIPITATION ACROSS THE SOUTHEAST WILL END THIS MORNING AS THE
FRONT PASSES.
NORTHWESTERLY FLOW WILL INCREASE DURING THE DAY AS HIGH PRESSURE
BUILDS SOUTHEASTWARD OUT OF CENTRAL CANADA. EXPECT WINDS AROUND
15 MPH GUSTING UP TO 25 MPH AT TIMES DURING THE AFTERNOON. THERE
IS NOT MUCH MOISTURE TO SPEAK OF BEHIND THE FRONT EXCEPT FOR THAT
WHICH WILL ORIGINATE FROM EVAPORATION OFF THE GREAT LAKES.
THEREFORE AM EXPECTING MOSTLY SUNNY SKIES THIS AFTERNOON. COLD
ADVECTION TODAY WILL KEEP TEMPERATURES FROM RISING ABOVE THE MIDDLE
70S ACROSS THE NORTH TO NEAR 80 ACROSS THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL DOMINATE OUR WEATHER THROUGH THURSDAY NIGHT.
EXPECT MOSTLY CLEAR SKIES WITH LIGHT WINDS UNDER THIS DRY AIRMASS.
HIGH TEMPERATURES WILL BE IN THE LOW TO MIDDLE 70S ON WEDNESDAY AND
THE MIDDLE TO UPPER 70S ON THURSDAY. NIGHTTIME LOWS WILL BE IN THE
LOW 50S TONIGHT AND WEDNESDAY NIGHT...WITH A FEW LOCATIONS
DROPPING ITO THE UPPER 40S WEDNESDAY NIGHT. OVERNIGHT LOWS
THURSDAY NIGHT WILL BE A TAD WARMER THAN WEDNESDAY NIGHT. HOWEVER...
THESE VALUES WILL STILL BE A SEASONABLY COOL MIDDLE TO UPPER 50S
FOR THE MOST PART.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
PERIOD BEGINS WITH A HIGH PRESSURE AREA STRETCHING ACROSS THE
OHIO VALLEY. THE HIGH WILL REMAIN ANCHORED OVER THE REGION
THURSDAY AND FRIDAY. MEANWHILE MODELS DROP MORE ENERGY INTO THE
ERN U.S. H5 TROF ON FRIDAY...CREATING A CUTOFF H5 LOW OVER THE
MID MS VALLEY. THIS MIGHT ACT TO LOWER THE CHANCE OF PCPN OVER
THE WEEKEND.
THE GFS IS STILL THE QUICKEST WITH THE RETURN FLOW OF MOISTURE ON
SATURDAY. KEPT A 20 TO 30 PERCENT CHC ON THE SOUTH AND SOUTHWEST
FOR SATURDAY. AS THE UPPER LOW DRIFTS SLOWLY E...SCT PCPN REMAINS
A POSSIBILITY ON SUNDAY WITH A BETTER CHANCE ON MONDAY AS AN
INVERTED SFC TROF FOCUS THE MOISTURE ACROSS THE REGION.
HIGHS WILL SLOWLY MODERATE...RISING FROM THE MID TO UPPER 70S ON
THURSDAY TO THE 80S OVER THE WEEKEND. LOWS WILL RISE FROM THE MID
TO UPPER 50S FRIDAY MORNING INTO THE 60S FOR THE WEEKEND.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE CONTINUING ACROSS
THE AREA EARLY THIS MORNING. THIS IS AHEAD OF A COLD FRONT THAT
WILL PUSH DOWN ACROSS THE REGION THROUGH LATE MORNING. THE SHOWERS
HAVE BEEN SHOWING A DECREASING TREND OVER THE LAST SEVERAL HOURS
AND THE LAST FEW RUNS OF THE HRRR AND THE 00Z NAM ARE PICKING UP
ON THIS. AS A RESULT...CHANCES OF SEEING PCPN AT THE ACTUAL TAF
SITES MAY BE RELATIVELY LOW...WITH A BETTER CHANCE OF
REDEVELOPMENT SOUTHEAST OF THE TAF SITES LATER THIS MORNING. CIGS
ARE GENERALLY RUNNING VFR AT THE MOMENT BUT DO EXPECT TO SEE THEM
DROP DOWN INTO MVFR CATEGORY LATER THIS MORNING AS WE START TO GET
INTO SOME LOW LEVEL CAA. ANY LOWER CLOUDS WILL SLOWLY LIFT INTO A
VFR DECK THROUGH LATE MORNING/EARLY AFTERNOON.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...SITES
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
144 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST AND CROSS THE OHIO VALLEY TONIGHT. HIGH
PRESSURE AND A COOLER...DRIER AIRMASS WILL THEN SETTLE INTO THE
AREA FOR THE MID TO LATER PART OF THE WEEK. THIS HIGH WILL SLOWLY
ERODE AT THE START OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WITH THUNDERSTORMS HAVING BLOSSOMED IN A VERY MOIST AIRMASS THIS
EVENING...HAVE INCREASED POPS TO LIKELY OVER MUCH OF THE AREA.
ADDITIONAL THUNDERSTORMS WILL BE LIKELY LATE TONIGHT AS A COLD
FRONT MAKES ITS WAY ACROSS THE AREA FROM THE NORTHWEST.
TEMPERATURES WILL NOT FALL OFF MUCH TONIGHT...WITH LOWS AROUND 70.
A FEW MARGINALLY STRONG THUNDERSTORMS ARE DEVELOPING. WITH A HIGH
WET BULB ZERO HEIGHT INDICATING A LIMITED LARGE HAIL
POTENTIAL...AND WITH WINDS ALOFT BEING A BIT WEAK...MAIN THREAT
APPEARS TO BE HEAVY RAIN...ESPECIALLY WITH PRECIPITABLE WATER
BEING OVER 2 INCHES ACROSS THE SOUTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
THINGS WILL DRY OUT NICELY BEHIND THE FRONT AND HIGH TEMPERATURES
WILL BE IN THE 70S WITH NIGHTTIME LOWS DROPPING INTO THE LOW TO
MID 50S UNDER GENERALLY CLEAR SKIES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
PERIOD BEGINS WITH A HIGH PRESSURE AREA STRETCHING ACROSS THE
OHIO VALLEY. THE HIGH WILL REMAIN ANCHORED OVER THE REGION
THURSDAY AND FRIDAY. MEANWHILE MODELS DROP MORE ENERGY INTO THE
ERN U.S. H5 TROF ON FRIDAY...CREATING A CUTOFF H5 LOW OVER THE
MID MS VALLEY. THIS MIGHT ACT TO LOWER THE CHANCE OF PCPN OVER
THE WEEKEND.
THE GFS IS STILL THE QUICKEST WITH THE RETURN FLOW OF MOISTURE ON
SATURDAY. KEPT A 20 TO 30 PERCENT CHC ON THE SOUTH AND SOUTHWEST
FOR SATURDAY. AS THE UPPER LOW DRIFTS SLOWLY E...SCT PCPN REMAINS
A POSSIBILITY ON SUNDAY WITH A BETTER CHANCE ON MONDAY AS AN
INVERTED SFC TROF FOCUS THE MOISTURE ACROSS THE REGION.
HIGHS WILL SLOWLY MODERATE...RISING FROM THE MID TO UPPER 70S ON
THURSDAY TO THE 80S OVER THE WEEKEND. LOWS WILL RISE FROM THE MID
TO UPPER 50S FRIDAY MORNING INTO THE 60S FOR THE WEEKEND.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE CONTINUING ACROSS
THE AREA EARLY THIS MORNING. THIS IS AHEAD OF A COLD FRONT THAT
WILL PUSH DOWN ACROSS THE REGION THROUGH LATE MORNING. THE SHOWERS
HAVE BEEN SHOWING A DECREASING TREND OVER THE LAST SEVERAL HOURS
AND THE LAST FEW RUNS OF THE HRRR AND THE 00Z NAM ARE PICKING UP
ON THIS. AS A RESULT...CHANCES OF SEEING PCPN AT THE ACTUAL TAF
SITES MAY BE RELATIVELY LOW...WITH A BETTER CHANCE OF
REDEVELOPMENT SOUTHEAST OF THE TAF SITES LATER THIS MORNING. CIGS
ARE GENERALLY RUNNING VFR AT THE MOMENT BUT DO EXPECT TO SEE THEM
DROP DOWN INTO MVFR CATEGORY LATER THIS MORNING AS WE START TO GET
INTO SOME LOW LEVEL CAA. ANY LOWER CLOUDS WILL SLOWLY LIFT INTO A
VFR DECK THROUGH LATE MORNING/EARLY AFTERNOON.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...CONIGLIO/FRANKS
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS NORMAN OK
628 AM CDT TUE AUG 13 2013
.DISCUSSION...
PLEASE SEE THE 12Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
A LINE OF SHOWERS AND THUNDERSTORMS WILL SLOWLY CONTINUE TO DRIFT
SOUTHWARD THROUGHOUT THE DAY. EXPECT AT LEAST MVFR TO APPLY OVER
MOST TERMINALS UNTIL PERHAPS LATER THIS AFTERNOON AND THIS
EVENING. GAG AND WWR WILL HAVE THE BEST FLIGHT CONDITIONS THROUGH
TODAY WITH ONLY BRIEF MVFR A POSSIBILITY EARLY THIS MORNING.
HOWEVER...THERE WILL STILL BE A CHANCE FOR TSRA THERE LATER THIS
AFTERNOON. CONFIDENCE IS NOT VERY HIGH REGARDING THE PREVIOUS
THOUGH SO WILL ONLY INCLUDE PROB30S FOR NOW. MVFR TO IFR CIGS ARE
EXPECTED FROM AROUND 09-12Z TOMORROW BEHIND THIS COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT TUE AUG 13 2013/
DISCUSSION...
MOIST CONVECTION HAS INCREASED ALONG THE 925 MB BAROCLINIC ZONE
EARLY THIS MORNING. THE NAM12 AND RUC13 ARE DEPICTING THIS VERY
WELL...AND INDICATE THE BEST WAA WILL OCCUR BETWEEN NOW THROUGH
ABOUT 12Z BEFORE THE FRONT BEGINS TO NUDGE SOUTHWARD. SLOW MOVING
STORMS ALONG THIS ZONE...TRAINING...AND VERY HIGH PWATS (OUN 00Z
1.92 IN) WILL SUPPORT HIGH RAINFALL RATES THROUGH EARLY THIS
MORNING. BY THIS AFTERNOON AND EVENING...A SHORTWAVE TROUGH MOVING
OUT OF KS WILL MOST LIKELY RESULT IN REDEVELOPMENT ACROSS MUCH
OF THE AREA. THE HEAVIEST RAIN IS EXPECTED ACROSS PORTIONS OF
SOUTHERN OK THIS AFTERNOON AND EVENING...AND PERHAPS EVEN W N TX
NEAR THE BOUNDARY LATE TONIGHT. THEREFORE...WILL EXTEND FFA
SOUTHWARD TO INCLUDE SOUTHERN PORTIONS OF OK WHERE SOME LOCALIZED
HEAVY RAINFALL ALREADY OCCURRED YESTERDAY. RAIN CHANCES WILL SHIFT
SOUTHWARD WITH THE BOUNDARY LATE TONIGHT THROUGH EARLY WED
MORNING. WILL KEEP MAX TEMPS CLOSE TO THE MET GUIDANCE FOR TODAY
CONSIDERING PERSISTENT STRATUS AND PRECIP CHCS THROUGH THE DAY.
SOME PARTS OF THE OKC METRO MAY NOT MAKE IT OUT OF THE 70S.
A SFC RIDGE WILL EXTEND THROUGH THE FA FROM THE NE WED BEHIND THE
FRONT KEEPING TEMPS WELL BELOW NORMAL. NORTHERLY FLOW ALOFT WILL
CONTINUE OVERHEAD THROUGH THE WORK WEEK...WITH THE POSSIBILITY OF
ADDITIONAL SUBTLE SHORTWAVE TROUGHS MOVING OVER THE PLAINS. POPS
WILL INCREASE AGAIN ON THURSDAY AS ONE SUCH WAVE TRAVERSES THE
REGION. AN EVEN MORE SIGNFICANT MID TO UPPER SHORTWAVE TROUGH IS
ANTICIPATED BY FRIDAY SO DECIDED TO INCREASE POPS TO AT LEAST CHC.
OVERALL...EXPECT AN UNUSUALLY COOL AND MOIST FORECAST THROUGH THE
ENTIRE FORECAST PERIOD AS NORTHERLY MID LEVEL FLOW REMAINS IN
PLACE WITH THE UPPER RIDGE AXIS WEST OF THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 81 69 83 67 / 80 40 20 10
HOBART OK 84 69 86 68 / 70 40 30 10
WICHITA FALLS TX 96 73 89 70 / 50 60 40 20
GAGE OK 80 65 82 64 / 60 40 20 20
PONCA CITY OK 82 66 82 64 / 50 40 20 10
DURANT OK 90 73 87 67 / 70 60 50 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OKZ004>032-040>043-
047-048.
TX...NONE.
&&
$$
02/03/03
AREA FORECAST DISCUSSION
NWS NORMAN OK
352 AM CDT TUE AUG 13 2013
.DISCUSSION...
MOIST CONVECTION HAS INCREASED ALONG THE 925 MB BAROCLINIC ZONE
EARLY THIS MORNING. THE NAM12 AND RUC13 ARE DEPICTING THIS VERY
WELL...AND INDICATE THE BEST WAA WILL OCCUR BETWEEN NOW THROUGH
ABOUT 12Z BEFORE THE FRONT BEGINS TO NUDGE SOUTHWARD. SLOW MOVING
STORMS ALONG THIS ZONE...TRAINING...AND VERY HIGH PWATS (OUN 00Z
1.92 IN) WILL SUPPORT HIGH RAINFALL RATES THROUGH EARLY THIS
MORNING. BY THIS AFTERNOON AND EVENING...A SHORTWAVE TROUGH MOVING
OUT OF KS WILL MOST LIKELY RESULT IN REDEVELOPMENT ACROSS MUCH
OF THE AREA. THE HEAVIEST RAIN IS EXPECTED ACROSS PORTIONS OF
SOUTHERN OK THIS AFTERNOON AND EVENING...AND PERHAPS EVEN W N TX
NEAR THE BOUNDARY LATE TONIGHT. THEREFORE...WILL EXTEND FFA
SOUTHWARD TO INCLUDE SOUTHERN PORTIONS OF OK WHERE SOME LOCALIZED
HEAVY RAINFALL ALREADY OCCURRED YESTERDAY. RAIN CHANCES WILL SHIFT
SOUTHWARD WITH THE BOUNDARY LATE TONIGHT THROUGH EARLY WED
MORNING. WILL KEEP MAX TEMPS CLOSE TO THE MET GUIDANCE FOR TODAY
CONSIDERING PERSISTENT STRATUS AND PRECIP CHCS THROUGH THE DAY.
SOME PARTS OF THE OKC METRO MAY NOT MAKE IT OUT OF THE 70S.
A SFC RIDGE WILL EXTEND THROUGH THE FA FROM THE NE WED BEHIND THE
FRONT KEEPING TEMPS WELL BELOW NORMAL. NORTHERLY FLOW ALOFT WILL
CONTINUE OVERHEAD THROUGH THE WORK WEEK...WITH THE POSSIBILITY OF
ADDITIONAL SUBTLE SHORTWAVE TROUGHS MOVING OVER THE PLAINS. POPS
WILL INCREASE AGAIN ON THURSDAY AS ONE SUCH WAVE TRAVERSES THE
REGION. AN EVEN MORE SIGNFICANT MID TO UPPER SHORTWAVE TROUGH IS
ANTICIPATED BY FRIDAY SO DECIDED TO INCREASE POPS TO AT LEAST CHC.
OVERALL...EXPECT AN UNUSUALLY COOL AND MOIST FORECAST THROUGH THE
ENTIRE FORECAST PERIOD AS NORTHERLY MID LEVEL FLOW REMAINS IN
PLACE WITH THE UPPER RIDGE AXIS WEST OF THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 81 69 83 67 / 80 40 20 10
HOBART OK 84 69 86 68 / 70 40 30 10
WICHITA FALLS TX 96 73 89 70 / 50 60 40 20
GAGE OK 80 65 82 64 / 60 40 20 20
PONCA CITY OK 82 66 82 64 / 50 40 20 10
DURANT OK 90 73 87 67 / 70 60 50 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OKZ004>032-040>043-
047-048.
TX...NONE.
&&
$$
02/03
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
956 PM CDT WED AUG 14 2013
.UPDATE...
MADE A COUPLE OF ADJUSTMENTS TO THE FORECAST FOR THE REMAINDER OF
TONIGHT. ADDED PATCHY FOG FOR EARLY TOMORROW MORNING FOR AREAS
PRIMARILY ALONG AND WEST OF THE MISSOURI RIVER. LOW STRATUS
DECK NOTED ON SATL AROUND WINNER AND IS PUSHING NWWD THIS
EVENING. LOW LEVEL MOISTURE ANTICIPATED TO INCREASE THE MISSOURI
RIVER VALLEY PARTICULARLY AROUND KPIR AND SOUTH WHERE RAIN MOVED
THROUGH EARLY THIS MORNING. ALSO ADJUSTED SKY COVER A BIT ACROSS
THE NE CWA TO ACCOUNT FOR SOME MID LVL CLOUDS ACROSS EASTERN NODAK
AS THEY ARE PUSHING SEWD THIS EVENING. ASSOC SHRA ACTIVITY AROUND
JAMESTOWN IS NOT EXPECTED TO MAKE IT FAR ENOUGH SOUTH TO AFFECT
NERN ZONES. RETAINED POPS ACROSS THE WEST FOR LATE TONIGHT AS
SHORTWAVE ENERGY APPROACHES WESTERN SOUTH DAKOTA FROM THE
NORTHWEST.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
PRETTY QUIET ACROSS THE CWA THIS AFTERNOON BUT WILL BE WATCHING
THE WESTERN CWA OVER THE NEXT FEW HOURS FOR THE POTENTIAL FOR A
FEW ISOLD THUNDERSHOWERS AS SHORTWAVE ENERGY APPROACHES FROM THE
MIDWEST. BEST SUPPORT DOES NOT ARRIVE UNTIL LATER THIS
EVENING...BUT DAYTIME HEATING ACROSS THE WESTERN CWA HAS ALLOWED
MLCAPE TO APPROACH 1000 J/KG. SHEAR IS LACKING ONCE AGAIN AS HAS
BEEN THE CASE THE PAST FEW DAYS. CURRENTLY SEEING A CONGESTED CU
FIELD ACROSS NORTH CENTRAL SD WITH RADAR ECHOES JUST BEGINNING TO
INCREASE OVER CORSON COUNTY. HRRR ACTUALLY PICKING UP ON THIS AND
SHOWING A FEW POPCORN TYPE LIGHT SHOWERS OR MAYBE A MODERATE
THUNDERSHOWER THROUGH LATE AFTERNOON. WILL MAINTAIN SLIGHT CHANCE
POPS FOR THE WESTERN CWA THROUGH THE AFTERNOON. MAIN SHORTWAVE
ENERGY APPROACHES THE REGION LATER THIS EVENING...BUT MODELS NOT
TOO IMPRESSED WITH THIS FOR OUR CWA. 12Z NSSL WRF SHOWS A LINE OF
SHOWERS AND STORMS MOVING INTO WESTERN SD LATER THIS EVENING BUT
DIES OUT AS ITS ENTERING THE WESTERN CWA. WILL MAINTAIN SMALL POPS
OVERNIGHT AS WELL...BUT HAVE TRIMMED THINGS DOWN TO DRY FOR THE
EASTERN CWA AS THERE JUST DOESNT SEEM TO BE ANY SUPPORT FOR
PRECIP. THERE REALLY IS NO LOW LEVEL JET TO SPEAK OF OVERNIGHT
EITHER.
WEAK SHORTWAVE ENERGY MOVES SOUTHEAST OVER THE AREA ON THURSDAY
BUT MODELS KEEP TRENDING DRIER AND DRIER FOR THIS...TO THE POINT
NOW WHERE MOST MODELS ARENT EVEN SHOWING ANY PRECIP FOR THE AREA.
HAVE SCALED BACK POPS QUITE A BIT...GOING DRY IN PLACES BUT
KEEPING A SLIGHT CHANCE GOING FOR MOST PLACES. AFTER
THURSDAY...THE WARM UP BEGINS AS UPPER RIDGING BUILDS OVER THE
HIGH PLAINS AND DAKOTAS.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
MAIN CHALLENGE IN THE LONG TERM WILL BE PRECIP CHANCES UNDER THE
DOMINANT UPPER RIDGE.
MODELS ARE NOT IN GOOD AGREEMENT TODAY IN THE EXTENDED. TOSSED OUT
THE GEM AS IT IS THE ONLY MODEL SHOWING A DEVELOPING TROPICAL
SYSTEM IN THE GULF THIS WEEKEND. THIS MAY CONTAMINATE QPF AND
PRESSURE FIELDS ALL THE WAY NORTH INTO THE DAKOTAS. GFS AND ECMWF
ARE BOTH FLIP FLOPPING WITH MOISTURE FIELDS THOUGH SFC PRESSURE
PROGS ARE SIMILAR. BOTH MODELS SHOW TWO TROFS MOVING ACROSS THE
DAKOTAS...ONE SUNDAY NIGHT/MONDAY AND ANOTHER TUESDAY
NIGHT/WEDNESDAY. HOWEVER THE GFS IS WET FOR THE FIRST AND DRY FOR
THE SECOND WHILE THE ECMWF IS OPPOSITE. STUCK WITH ALLBLEND POPS
SUNDAY NIGHT/MONDAY AS 30S/40S SEEM REASONABLE AT THIS POINT. WENT
DRIER THAN ALLBLEND FOR THE END OF THE PERIOD BASED ON INTER
OFFICE COLLABORATION.
TEMPERATURES SHOULD BE ON THE RISE THROUGH THE PERIOD WITH HIGHS
IN THE UPPER 80S TO LOWER 90S EXPECTED.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
FAIRLY TRANQUIL CONDITIONS WILL CONTINUE TO PREVAIL ACROSS THE
LOCAL TERMINALS AS THE REGION REMAINS BETWEEN HIGH PRESSURE TO THE
EAST AND LOW PRESSURE TO THE WEST. VFR CONDITIONS AND LIGHT SOUTH
TO SOUTHEAST WINDS CAN BE EXPECTED TONIGHT INTO THURSDAY. AN
ISOLATED SHOWER OR THUNDERSTORM IS POSSIBLE OVER THE WESTERN TAF
SITES LATE TONIGHT. MVFR CIGS/VSBY IS STILL POSSIBLE EARLY
THURSDAY MORNING AROUND KPIR. VFR CONDITIONS FOR ALL TERMINALS CAN
BE EXPECTED DURING THE DAYTIME THURSDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...VIPOND
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...VIPOND
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
730 PM CDT WED AUG 14 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
PRETTY QUIET ACROSS THE CWA THIS AFTERNOON BUT WILL BE WATCHING
THE WESTERN CWA OVER THE NEXT FEW HOURS FOR THE POTENTIAL FOR A
FEW ISOLD THUNDERSHOWERS AS SHORTWAVE ENERGY APPROACHES FROM THE
MIDWEST. BEST SUPPORT DOES NOT ARRIVE UNTIL LATER THIS
EVENING...BUT DAYTIME HEATING ACROSS THE WESTERN CWA HAS ALLOWED
MLCAPE TO APPROACH 1000 J/KG. SHEAR IS LACKING ONCE AGAIN AS HAS
BEEN THE CASE THE PAST FEW DAYS. CURRENTLY SEEING A CONGESTED CU
FIELD ACROSS NORTH CENTRAL SD WITH RADAR ECHOES JUST BEGINNING TO
INCREASE OVER CORSON COUNTY. HRRR ACTUALLY PICKING UP ON THIS AND
SHOWING A FEW POPCORN TYPE LIGHT SHOWERS OR MAYBE A MODERATE
THUNDERSHOWER THROUGH LATE AFTERNOON. WILL MAINTAIN SLIGHT CHANCE
POPS FOR THE WESTERN CWA THROUGH THE AFTERNOON. MAIN SHORTWAVE
ENERGY APPROACHES THE REGION LATER THIS EVENING...BUT MODELS NOT
TOO IMPRESSED WITH THIS FOR OUR CWA. 12Z NSSL WRF SHOWS A LINE OF
SHOWERS AND STORMS MOVING INTO WESTERN SD LATER THIS EVENING BUT
DIES OUT AS ITS ENTERING THE WESTERN CWA. WILL MAINTAIN SMALL POPS
OVERNIGHT AS WELL...BUT HAVE TRIMMED THINGS DOWN TO DRY FOR THE
EASTERN CWA AS THERE JUST DOESNT SEEM TO BE ANY SUPPORT FOR
PRECIP. THERE REALLY IS NO LOW LEVEL JET TO SPEAK OF OVERNIGHT
EITHER.
WEAK SHORTWAVE ENERGY MOVES SOUTHEAST OVER THE AREA ON THURSDAY
BUT MODELS KEEP TRENDING DRIER AND DRIER FOR THIS...TO THE POINT
NOW WHERE MOST MODELS ARENT EVEN SHOWING ANY PRECIP FOR THE AREA.
HAVE SCALED BACK POPS QUITE A BIT...GOING DRY IN PLACES BUT
KEEPING A SLIGHT CHANCE GOING FOR MOST PLACES. AFTER
THURSDAY...THE WARM UP BEGINS AS UPPER RIDGING BUILDS OVER THE
HIGH PLAINS AND DAKOTAS.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
MAIN CHALLENGE IN THE LONG TERM WILL BE PRECIP CHANCES UNDER THE
DOMINANT UPPER RIDGE.
MODELS ARE NOT IN GOOD AGREEMENT TODAY IN THE EXTENDED. TOSSED OUT
THE GEM AS IT IS THE ONLY MODEL SHOWING A DEVELOPING TROPICAL
SYSTEM IN THE GULF THIS WEEKEND. THIS MAY CONTAMINATE QPF AND
PRESSURE FIELDS ALL THE WAY NORTH INTO THE DAKOTAS. GFS AND ECMWF
ARE BOTH FLIP FLOPPING WITH MOISTURE FIELDS THOUGH SFC PRESSURE
PROGS ARE SIMILAR. BOTH MODELS SHOW TWO TROFS MOVING ACROSS THE
DAKOTAS...ONE SUNDAY NIGHT/MONDAY AND ANOTHER TUESDAY
NIGHT/WEDNESDAY. HOWEVER THE GFS IS WET FOR THE FIRST AND DRY FOR
THE SECOND WHILE THE ECMWF IS OPPOSITE. STUCK WITH ALLBLEND POPS
SUNDAY NIGHT/MONDAY AS 30S/40S SEEM REASONABLE AT THIS POINT. WENT
DRIER THAN ALLBLEND FOR THE END OF THE PERIOD BASED ON INTER
OFFICE COLLABORATION.
TEMPERATURES SHOULD BE ON THE RISE THROUGH THE PERIOD WITH HIGHS
IN THE UPPER 80S TO LOWER 90S EXPECTED.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
FAIRLY TRANQUIL CONDITIONS WILL CONTINUE TO PREVAIL ACROSS THE
LOCAL TERMINALS AS THE REGION REMAINS BETWEEN HIGH PRESSURE TO THE
EAST AND LOW PRESSURE TO THE WEST. VFR CONDITIONS AND LIGHT SOUTH
TO SOUTHEAST WINDS CAN BE EXPECTED TONIGHT INTO THURSDAY. AN
ISOLATED SHOWER OR THUNDERSTORM IS POSSIBLE OVER THE WESTERN TAF
SITES LATE TONIGHT. MVFR CIGS/VSBY IS STILL POSSIBLE EARLY
THURSDAY MORNING AROUND KPIR. VFR CONDITIONS FOR ALL TERMINALS CAN
BE EXPECTED DURING THE DAYTIME THURSDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...VIPOND
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...VIPOND
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
203 PM MDT TUE AUG 13 2013
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 201 PM MDT TUE AUG 13 2013
WATER VAPOR IMAGERY CONTINUES TO SHOW BLOCKING PATTERN ACROSS THE
CONUS WITH UPPER RIDGING CENTERED ACROSS THE ROCKIES INTO THE HIGH
PLAINS. SURFACE ANALYSIS SHOWS HIGH PRESSURE ACROSS THE DAKOTAS
WITH THE FRONTAL BOUNDARY STRETCHED ACROSS CENTRAL SD. STORMS HAVE
STARTED FIRING ACROSS NORTHWEST SD INTO THE BLACK HILLS AREA WITH
A COUPLE SEVERE AT THIS TIME. STORMS WILL CONTINUE TO DEVELOP OVER
THE NEXT FEW HOURS OVER THE AREA. THE BEST INSTABILITY IS ACROSS
SE MONTANA THROUGH WESTERN SD WITH MLCAPE OF 2000 TO 2500 J/KG.
LOW LEVEL SHEAR IS OVERALL WEAK...BUT IS BEST ACROSS NW SD. WITH
DEEP INSTABILITY...ENOUGH SHEAR FOR CONTINUED SUPERCELL
DEVELOPMENT INTO THIS EVENING...AND PERHAPS AN ISOLATED SEVERE
STORM THROUGH THE OVERNIGHT HOURS. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS TODAY AND TONIGHT. STORMS WILL AGAIN BE SLOW
MOVING AND HAVE THE POTENTIAL FOR PRODUCING LOCALLY HEAVY
RAINFALL.
LITTLE CHANGE TO THE OVERALL PATTERN TOMORROW WITH UPPER RIDGING
AXIS WEST OF THE AREA. LINGERING STORMS ARE POSSIBLE ACROSS THE AREA
TOMORROW MORNING...BUT A REDEVELOPMENT OF STORMS ARE EXPECTED IN THE
AFTERNOON. INSTABILITY IS PROGGED TO BE WEAKER TOMORROW...WITH
RELATIVELY WEAK SHEAR CONTINUING. SUBTLE WAVES WILL HELP TRIGGER
CONVECTION...BUT ASIDE FOR AN ISOLATED SEVERE STORM OR TWO...SEVERE
WEATHER IS NOT EXPECTED. WEAK STEERING WINDS WILL AGAIN RESULT IN
SLOW STORM MOTION.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 201 PM MDT TUE AUG 13 2013
MEAN WESTERN NOAM RIDGING TO REMAIN IN THE PERIOD...WITH DOWNSTREAM
MEAN NEGATIVE HEIGHT ANOMALIES LINGERING BUT WEAKENING IN THE
EASTERN NOAM. PATTERN CHANGE WILL OCCUR AS THE NE PAC PERSISTENT
UPPER TROUGH IS FORECAST TO CYCLE...WITH UPPER RIDGING EXPECTED OVER
THE NORTHERN PLAINS FRIDAY THROUGH MUCH OF NEXT WEEK. MID LEVEL
TROUGH AND ASSOCIATED SFC REFLECTION STILL ON TRACK TO PROGRESS
THROUGH THE REGION SUNDAY/SUNDAY NIGHT...WITH CONTINUED CHANCES FOR
SHRA/TS THEN. OTHERWISE...HAVE KEPT THE REMAINDER OF THE PERIOD
DRY...SAVE FOR THIS THUR WHEN THE LAST IN A SERIES OF DISTURBANCES
WILL EXIT THE REGION. FAIRLY WARM TEMPS EXPECTED AS THE UPPER RIDGE
TILTS OVER THE REGION SAT-SUN...THEN AGAIN TUESDAY WITH A RESURGENCE
OF THE WESTERN NOAM RIDGE. THERE IS SOME LINGERING UNCERTAINTY TO
HOW FAR EAST AND NORTH THE UPPER RIDGE WILL BUILD...WHICH WILL HAVE
A LARGE IMPACT OF LOCAL TEMPS/MOISTURE. DOWNSTREAM DEVELOPMENTS WILL
ALSO HAVE AN EFFECT ON THIS PROCESS...MAINLY BEING IF THE PERSISTENT
EASTERN NOAM TROUGH RETURNS...HINTED AT IN THE ECMWF NEXT WEEK
BEYOND THE CURRENT FORECAST PERIOD. BEFORE THE NEXT PATTERN IS
ESTABLISHED...SLIGHTLY PROGRESSIVE FLOW/WARMER TEMPS/AND DECREASING
LL MOISTURE LOOKS PROBABLE IN THE PERIOD. HAVE OPTED TO SIDE ON THE
WARMER SIDE OF MIDDLE GUIDANCE NUMBERS GIVEN THE DIRER
PATTERN...WHICH LOOKS TO REMAIN THROUGH MUCH OF THE PERIOD ATTM.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON
ISSUED AT 201 PM MDT TUE AUG 13 2013
VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE PERIOD SAVE IN AN
NEAR SCT TS THIS AFTERNOON AND TONIGHT. MVFR/IFR CIGS WILL BE
POSSIBLE ONCE AGAIN TOWARD DAWN OVER THE EASTERN FA...WITH
EASTERLY FLOW POSSIBLY PUSHING STRATUS BACK INTO THE EASTERN BH
FOOTHILLS TUE MORNING. DID HINT AT THIS IN THE RAP TAF.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...13
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
346 PM CDT TUE AUG 13 2013
.DISCUSSION...
MUCH CONVECTIVE ACTIVITY OCCURRING ALONG A NORTHERN TEXAS (QUASI)
STATIONARY BOUNDARY THAT MAY EVENTUAL IMPACT OUR NORTH(EAST)ERN
COUNTIES WITHIN THE NEXT 4 TO 6 HOURS. A VERY HEATED AND MOIST
DOWNSTREAM AIR MASS FOR THIS STATIONARY BOUNDARY...OR SUBSEQUENT
CONVECTIVE OUTFLOW...TO WORK WITH IN THE COMING 24-36 HOURS.
THERE IS STILL SUBSIDENCE TO WORK WITH AS THERE HAVE BEEN RECENT
HEIGHT RISES AND A FEW DEGREES OF WARMTH AT THE 85-7H LEVELS...BUT
THE UPPER LEVELS REMAIN FAIRLY DIFFULENT AS EAST TEXAS FALLS WITHIN
A (RELATIVELY) MILD MID-UPPER LEVEL HEIGHT WEAKNESS BETWEEN DESERT
SOUTHWEST AND FLORIDA-CENTERED RIDGING.
ALL OF THE THERMODYNAMIC INDICES ARE THERE TO SUPPORT RETURNING
SCATTERED SHOWERS AND STORMS BEGINNING AS EARLY AS MID-WEDNESDAY
MORNING. K-INDICES AROUND 40...L.I. IN THE -5 REALM...AND ABOVE
1 K J/KG CAPES FROM THE GFS/NAM PROGS OVER THE NORTHERN CWA
INCREASE THE SHOWER/STORM PROBABILITY. YES...THERE WILL BE SOME
SUBSIDENCE TO DEAL WITH...BUT WITH A CONSISTENT RUN-TO-RUN THEME
OF INTRODUCING WEAK LOWER MS VALLEY TROUGHING (AND WITNESSING WHAT
IS ONGOING ACROSS DFW`S FA)...HAD TO BITE ON THE LIKELY SIDE OF
POPS. GREATER THAN 2 INCH PWATS WILL POOL ALONG `A` BOUNDARY...WHETHER
THAT BE MORE OF A SYNOPTIC OR A SERIES OF MESOSCALE (UPSTREAM
OUTFLOW) BOUNDARIES. OTHER THAN SUBSIDENCE AS A RAIN INHIBITER...THE
ONLY OTHER NEGATIVE TO MORE WIDESPREAD COVERAGE WOULD BE THAT THE
REGION DOES FALL INTO MORE OF A RR QUAD OF THE JET (ALTHOUGH 25-3H
FLOW REMAINS DIFFULENT).
NEEDLESS TO SAY...BUT WHAT EVOLVES TOMORROW WILL DRIVE THURSDAY`S
FORECAST. SINCE THE FORECAST IS MORE WET TOMORROW...ANTICIPATING
THAT THERE WILL BE SOME RESIDUAL BOUNDARIES LEFT OVER IN THE MIX.
A LESS-WORKED OVER SOUTHERN CWA AIR MASS...WITH POSSIBLE LEFT-OVER
WEDNESDAY SMALL SCALE BOUNDARIES (AND MAYBE SOME ASSISTANCE FROM
THE LOCAL BREEZE?) WILL KEEP CHANCE POPS IN PLAY CLOSER TO THE
COAST THURSDAY INTO FRIDAY. A MUCH DRIER AIR MASS FILTERING IN
ALONG THE WESTERN LEG OF A EASTERN-BASED MID-UPPER TROUGH AXIS
WILL COME OVER US DURING THE WEEKEND...SUBSTANTIALLY LOWERING
RAIN CHANCES.
THE EXTENDED SHOWS NOT MUCH IN THE WAY OF ANY DISCERNIBLE WEATHER
FEATURE THAT WILL INCREASE RAIN CHANCES BEYOND THE LOCAL SCALE
BREEZES. IF ANYTHING...RIDGING TAKES MORE OF A GRIP AND MID-LEVELS
ARE MODELED TO WARM BACK UP INTO THE LOWER 20S BY THIS TIME NEXT
WEEK. AS HAS BEEN THE CASE THESE PAST FEW DAYS...THE BAY OF CAMPECHE
HAS REMAINED SOMEWHAT ACTIVE...WITH THE NWP SUITE MAINTAINING
LOWERING PRESSURES AND A GREATER THAN 2 INCH PW AIR MASS. CENTRAL
GULF SHEAR REMAINS STOUT (30 KTS BETWEEN THE TWO UPPER RIDGES) SO
NOT TOO WORRIED WITH ANY CLOSED-OFF CIRCULATION MOVING TOO FAR
NORTH OF THE BAY. 31
&&
.MARINE...
A RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP MAINLY LIGHT ONSHORE WINDS AND LOW SEAS IN PLACE THROUGH THE
MIDDLE OF THE WEEK. A WEAK FRONT IS STILL EXPECTED TO APPROACH THE
COAST FROM THE NORTH AND NORTHEAST ON WEDNESDAY NIGHT AND THURSDAY.
THIS BOUNDARY COULD BRING THE AREA A BRIEF PERIOD OF OFFSHORE WINDS.
A WEAK TROUGH OF LOW PRESSURE OVER THE CENTRAL GULF WILL MAINTAIN E-NE
WINDS THROUGH SUNDAY. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 76 94 73 95 75 / 20 60 20 20 10
HOUSTON (IAH) 78 96 76 93 74 / 20 60 30 40 20
GALVESTON (GLS) 83 91 81 90 81 / 10 40 40 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1230 PM CDT TUE AUG 13 2013
.UPDATE...
LATE MORNING SFC ANALYSIS SHOWS A WEAK OUTFLOW BOUNDARY THAT HAD
MOVED TO THE SRN EDGE OF THE FCST AREA EARLIER HAD NOW BEGUN TO
DISSIPATE WITH LIGHT SOUTH WINDS BEGINNING TO OVERTAKE THE SRN
SOUTH PLAINS. MEANWHILE...ANOTHER WEAK BOUNDARY WAS BEGINNING TO
SHARPEN ACROSS THE NRN PANHANDLE...AND IT IS THIS BOUNDARY THAT
THE NAM AND RAP SEEM TO BE KEYING ON FOR AFTN THUNDERSTORM
DEVELOPMENT. 12Z MODEL RUN WANTS TO SHIFT THIS BOUNDARY A BIT
FURTHER SWD THAN PREVIOUS FCST AND AS A RESULT HAVE SHIFTED AXIS
OF HIGHER POPS FOR THE 18Z-00Z TIME FRAME SWD AS WELL. OTHER
CHANGES TO AFTN WERE EVEN MORE MINOR...MAINLY ADJUSTING FOR TRENDS
IN DEW POINT AND WIND.
HAVE LEFT EVENING FCST ALONE FOR NOW. MAY ALSO NEED TO SHIFT
HIGHER POPS SWD THERE...BUT WOULD LIKE TO SEE THE WHITES OF ITS
EYES IN RELATION TO EXPECTED INITIATION ZONE BEFORE MAKING
CHANGES. SECONDARY PRECIP MAY COME WITH HIGH TERRAIN STORMS FROM
NERN NM SURGING SEWD INTO MOIST UPSLOPE FLOW AIDED BY ABOUT 30 KT
FLOW AT 500 MB. ATTM HIGH CHANCE TO LIKELY POPS FAVORING NRN ZONES
STILL APPROPRIATE WITH REEVALUATION FOR THE AFTN PACKAGE.
&&
.AVIATION...
WEAK SFC BOUNDARY SHOULD FOCUS SCATTERED CONVECTION LATE AFTN
EARLY EVENING PROBABLY IN A BAND NEAR BOTH TERMINALS...POSSIBLY
BETWEEN THE TWO...BUT PROBABLY HIGH ENOUGH CONFIDENCE TO INSERT A
TEMPO MENTION. NAM MODEL SEEMS TO BE OVERPLAYING POTENTIAL FOR
MVFR CIGS LATE TONIGHT. THIS IS A BIAS OF THAT MODEL AND FOR NOW
WILL LEAN TOWARD THE MORE OPTIMISTIC GFS.
&&
.PREV DISCUSSION... /ISSUED 639 AM CDT TUE AUG 13 2013/
AVIATION...
A COLD FRONT MOVING THROUGH THE AREA WILL BRING A N-NE WIND SHIFT
TO KLBB BY ABOUT 13Z...FOLLOWED BY PREVAILING E-NE WINDS AT BOTH
TERMINALS THROUGH THE REMAINDER OF THE FCST. SCATTERED SHOWERS AND
THUNDERSTORMS MAY AFFECT EITHER/BOTH TERMINALS THIS AFTERNOON AND
EVENING AND WE HAVE A PROB30 MENTION AT BOTH. THE SHOWER ACTIVITY
MAY CONTINUE OVERNIGHT BUT WITH LOW CONFIDENCE IN THE PARTICULARS.
ALSO...THERE IS SOME INDICATION THAT LOW CEILINGS NEAR OR BELOW
2000 FT MAY DEVELOP AT EITHER TERMINAL...MORE LIKELY AT KCDS. WE
WILL LEAVE MENTION OUT OF TAF FOR NOW UNTIL THERE IS A STRONGER
INDICATION.
PREV DISCUSSION... /ISSUED 419 AM CDT TUE AUG 13 2013/
SHORT TERM...
INITIAL OUTFLOW BOUNDARY MOVED THROUGH MOST OF THE AREA LAST NIGHT
WITH WEAK EASTERLY WINDS NOTED ACROSS ALL BUT THE SW SPLNS...WHERE
WINDS REMAINED SOUTHERLY. WE/VE SEEN SOME MORNING SHOWER ACTIVITY
CROP UP JUST WEST OF THE STATE LINE AS WE CONTINUE TO SEE SOME WEAK
UPPER-AIR RIPPLES ROTATE AROUND A VERY FLAT RIDGE CENTERED OVER SW
TX. FARTHER TO THE NORTH...A W-E BAND OF MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS STRETCHED ACROSS THE NRN TX PANHANDLE WITH A
WELL-DEFINED OUTFLOW/COLD FRONT BOUNDARY MOVING SOUTH...APPROACHING
KAMA AT 3 AM. THIS BOUNDARY SHOULD MOVE INTO OUR NRN ZONES EARLY
THIS MORNING...AND POSSIBLY FARTHER SOUTH BEFORE LOSING MOMENTUM.
SURFACE WINDS WILL BECOME FAIRLY LIGHT ACROSS THE AREA
TODAY...LIKELY WITH A SMALL NORTH TO EAST COMPONENT. THIS SHOULD
MAINTAIN HEALTHY MOISTURE IN PLACE IN THE LOW-LEVELS. ALOFT...WATER
VAPOR IMAGERY THIS MORNING SHOWS A SHORTWAVE LIFTING NORTH ACROSS
THE GREAT BASIN...ANOTHER SWINGING SOUTH THROUGH THE DAKOTAS...WITH
CONVOLUTED FLOW IN-BETWEEN THESE TWO SYSTEMS FROM THE SRN ROCKIES
INTO THE HIGH PLAINS. AN UPPER-LVL JET WILL ADVANCE INTO SRN CO/KS
TODAY...WITH A BELT OF 30+ KT MID-LVL WINDS DEVELOPING ACROSS NE NM
TO WRN OKLA THIS AFTERNOON...AND SPREADING INTO THE NRN SPLNS TO RED
RIVER VALLEY TONIGHT. LIFT WITH THE JET WILL COUPLE WITH LOW-LVL
LIFT IN THE FRONT/OUTFLOW ZONE AND A MODERATELY UNSTABLE AIRMASS TO
SUPPORT CONVECTIVE CHANCES THROUGH THE DAY AND ON INTO THE NIGHT.
HIGH-RES GUIDANCE SUGGESTS THAT THE ACTIVITY IN THE PANHANDLE WILL
SAG SOUTH INTO OUR NRN ZONES THIS MORNING AND WEAKEN. THEN THIS
AFTERNOON...WE SHOULD SEE SCATTERED CONVECTIVE DEVELOPMENT PRIMARILY
ACROSS THE NW PORTIONS OF THE SPLNS AND SWRN TX PANHANDLE...ALTHOUGH
WE CAN/T RULE OUT DEVELOPMENT ALMOST ANYWHERE. STORMS WILL GENERALLY
MOVE EAST AND WILL TAP INTO MLCAPES RUNNING 1000 TO 2000 J/KG AND
0-6 KM BULK SHEAR OF 30 KTS SOUTH TO 40+ KT NORTH. THIS ENVIRONMENT
WILL SUPPORT SOME SEVERE STORM POTENTIAL /MAINLY DAMAGING WIND
GUSTS/ THIS THREAT WILL BE HIGHER ACROSS THE NRN ZONES WHERE THE
SHEAR WILL BE GREATER...BUT WE WILL HAVE TO MONITOR JUST WHERE THE
OUTFLOW BOUNDARY ACTUALLY SETS UP TO ENHANCE LOW-LVL CONVERGENCE AND
LIFT. ALSO...STORM CELLS POSSIBLY TRAINING ON THE COLD SIDE OF THE
BOUNDARY COULD LEAD TO SOME LOCALLY HEAVY RAIN POTENTIAL THIS
EVENING. AS WE HEAD INTO THE OVERNIGHT HOURS...THE FORECAST
CONFIDENCE DECREASES AS BEST UPPER-LEVEL LIFT WILL REMAIN POSITIONED
ACROSS THE NORTH...BUT BEST LOW-LVL FOCUS WILL KEEP SHIFTING
SOUTH...WITH THE FRONT MOVING ON INTO THE PERMIAN BASIN BY EARLY WED
MORNING. THE BULK OF GUIDANCE KEEPS THE HIGHEST RAIN CHANCES PINNED
ACROSS THE NORTH. OVERALL COVERAGE AND STRENGTH OF ACTIVITY IS
EXPECTED TO WANE AFTER MIDNIGHT...ALTHOUGH WE WILL HAVE TO WATCH
BACK TO THE WEST WHERE A OVERNIGHT COMPLEX MAY BEGIN TO FORM NEAR
THE STATE LINE WHERE LIFT FROM NEXT SHORTWAVE STARTS TO IMPINGE ON
POST-FRONTAL UPSLOPE.
LONG TERM...
AN UNSETTLED STRETCH OF WEATHER WILL KICK OFF THE EXTENDED FORECAST
THANKS TO A PERIOD OF NORTHWESTERLY FLOW ALOFT AND A FRONTAL
BOUNDARY IN/NEAR THE AREA. HOWEVER...THE DEVIL IS IN THE DETAILS
WITH MUCH UNCERTAINTY IN THE SPATIAL AND TEMPORAL DISTRIBUTION OF
THE BEST SHOWER/STORM CHANCES RESULTING FROM UNKNOWNS REGARDING
THE EXACT FRONTAL POSITION AND TIMING OF SUBTLE SHORTWAVES MOVING
THROUGH THE FLOW ALOFT.
NORTHWESTERLY MID-LEVEL FLOW WILL BEGIN TO TAKE SHAPE ON WEDNESDAY
AS AN UPPER RIDGE AMPLIFIES OVER THE ROCKIES DOWNSTREAM OF A LARGE
VORTEX CENTERED OFF THE COAST OF BRITISH COLUMBIA. WEST TEXAS WILL
BE POSITIONED BETWEEN THE RIDGE AND LARGE-SCALE TROUGHING ACROSS THE
EASTERN PORTION OF THE CONTINENT. AT THE SFC...A FRONTAL BOUNDARY IS
PROGGED TO SETTLE SOUTHWARD THROUGH MOST IF NOT THE ENTIRE CWA EARLY
WEDNESDAY...WITH RICH POST-FRONTAL MOISTURE ADVECTING IN ON UPSLOPE
WINDS. THIS MOIST ENVIRONMENT WILL READILY SUPPORT PRECIPITATION AND
EFFICIENT RAINFALL RATES GIVEN ANY SUBTLE FORCING FOR ASCENT.
INITIALLY THE FRONTAL FORCING AND PERHAPS WEAK UPPER SUPPORT WILL
KEEP DECENT RAIN CHANCES GOING ON WEDNESDAY...WITH ADDITIONAL
CONVECTION FOCUSED ALONG AND BEHIND THE FRONT AS DAYTIME HEATING
PEAKS AND A POSSIBLE WEAK SHORTWAVE TROUGH APPROACHES. ONE
QUESTION MARK IS HOW MUCH HEATING CAN DEVELOP WEDNESDAY AFTERNOON
WITH THE NAM SUGGESTING LOW CLOUDS MAY HOLD TOUGH MUCH OF THE DAY
AND LIMIT POTENTIAL INSTABILITY. THE ECMWF AND GFS ARE MORE
OPTIMISTIC AND PROJECT SBCAPES CLIMBING TO NEAR OR IN EXCESS OF
1500 J/KG. IF THE STRONGER INSTABILITY IS REALIZED IT COULD BRING
THE POTENTIAL FOR A FEW STRONG TO SEVERE STORMS AS 0-6 KM SHEAR
CLIMBS TO AROUND 35 KNOTS. WE WILL ALSO LOOK FOR THE POSSIBILITY
OF A MCS ROLLING IN LATE FROM THE NORTH...THOUGH THE COOLER AND
MORE STABLE NAM SOLUTION DOES NOT SUPPORT THIS. FOR NOW...HAVE
MADE ONLY MINOR ADJUSTMENTS TO THE POP/WX GRIDS...MAINTAINING A
30-40 PERCENT CHANCE OF STORMS WEDNESDAY AND WEDNESDAY NIGHT. THE
OVERALL SETUP WILL NOT CHANGE MUCH THURSDAY...THOUGH THE FRONTAL
ZONE MAY RETREAT A BIT...SO THUNDER CHANCES WILL CONTINUE WITH NWP
CURRENTLY SUGGESTING ANOTHER SHORTWAVE WILL APPROACH FROM THE
NORTHWEST LATE KEEPING STORM CHANCES GOING LATE INTO THE NIGHT.
THE UPPER FLOW WILL TURN MORE NORTHERLY ON FRIDAY AS THE WESTERN
RIDGE FURTHER AMPLIFIES AND BEGINS TO EDGE EASTWARD. THIS WILL
REDUCE THE CHANCE THAT CONVECTION ORIGINATING OVER THE HIGHER
ELEVATION OF NM AND CO CAN MAKE ITS WAY TO THE SOUTH PLAINS...BUT
WITH THE RESIDUAL FRONTAL BOUNDARY STILL IN THE AREA AND A SHORTWAVE
GRAZING WEST TEXAS FROM THE EAST...HAVE MAINTAINED LOW STORM
CHANCES. DRIER AIR WILL GRADUALLY ADVECT IN ALOFT OVER THE WEEKEND
AS THE UPPER RIDGE BENDS FURTHER EASTWARD AND A DRYING TREND WILL
LIKELY ENSUE. THIS RIDGE WILL GRADUALLY BREAKDOWN LATE WEEKEND INTO
EARLY NEXT WEEK AS A TROUGH EMERGES FROM THE CENTRAL/NORTHERN
ROCKIES. THIS COULD BEND THE MONSOON MOISTURE EASTWARD...PERHAPS
REJUVENATING STORM CHANCES.
REGARDING TEMPERATURES...TENDED TO FAVOR THE COOL SIDE OF GUIDANCE
GIVEN THE EXPECTED CLOUD COVER AND RAIN IN THE AREA MID TO LATE
WEEK. TEMPERATURES WILL GRADUALLY TREND UPWARD BY THIS WEEKEND AS
THE UPPER RIDGE BENDS OVER AND SOUTHERLY LOW-LEVEL FLOW RETURNS TO
WEST TEXAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 85 62 84 61 86 / 40 50 40 40 30
TULIA 86 64 82 63 84 / 40 50 40 40 30
PLAINVIEW 89 65 81 64 84 / 30 40 40 40 30
LEVELLAND 91 66 84 65 88 / 30 30 40 40 30
LUBBOCK 91 68 83 65 86 / 30 30 40 40 30
DENVER CITY 94 66 88 65 91 / 20 20 40 30 30
BROWNFIELD 93 68 86 65 90 / 20 20 40 40 30
CHILDRESS 89 68 85 68 87 / 40 60 40 40 30
SPUR 93 70 86 68 89 / 30 30 40 40 30
ASPERMONT 95 72 89 69 90 / 20 30 40 40 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1200 AM CDT TUE AUG 13 2013
.AVIATION...
VFR CONDITIONS EXPECTED THROUGH AT LEAST 18Z TUESDAY...WITH THE
POTENTIAL FOR TSRA TOMORROW AFTERNOON FIRST AT CDS...AND LATER AT
LBB. THESE STORMS WILL BE MADE POSSIBLE IN PART BY A PASSING COLD
FRONT...THE TIMING OF WHICH IS STILL RELATIVELY UNCERTAIN.
CONFIDENCE IS HIGHER IN TSRA AT CDS...WITH LOWER PROBABILITIES AT
LBB OWING TO THE UNCERTAINTIES RELATED TO THE TIMING OF THE
FRONTAL PASSAGE. PERIODIC MVFR CONDITIONS WILL BE POSSIBLE IF
STORMS DRIFT OVER EITHER TERMINAL...BUT OPTED TO LEAVE OUT
EXPLICIT MENTION UNTIL THE TIMING OF THUNDERSTORM ACTIVITY BECOMES
MORE CLEAR.
&&
PREV DISCUSSION... /ISSUED 346 PM CDT MON AUG 12 2013/
SHORT TERM...
WEATHER PATTERN OVER THE NEXT DAY WILL BE LARGELY DRIVEN BY
ELONGATED UPPER HIGH ALONG THE GULF COAST WITH A RIDGE EXTENDING
FROM AROUND THESE PARTS UP TO THE CANADIAN PRAIRIES. MONSOON
MOISTURE CONTINUES TO WRAP AROUND THE PERIPHERY OF THE HIGH CENTER
GENERALLY STREAMING FROM NORTHEASTERN NEW MEXICO TO THE TEXAS
PANHANDLE AND BEYOND. AREA OF SYNOPTIC SCALE LIFT IS EVIDENT TO OUR
NORTH AND NORTHWEST AND THIS IS WHERE TSTM ACTIVITY INITIATED.
HOWEVER...TO THE SOUTH...ACROSS OUR REGION...AXIS OF THETA-E MAXIMA
HAS HELPED INITIATE ISOLATED CONVECTION FROM DORA TO MEMPHIS. GIVEN
THAT THESE SHOWERS DEVELOPED BY 2PM...INDICATIONS ARE THAT THE
ATMOSPHERE IS SUFFICIENTLY MOIST TO SUPPORT AT LEAST SCATTERED STORMS
FOR MUCH OF THE AFTERNOON INTO THE EVENING HOURS...FAVORING THE
NORTHERN HALF OF THE AREA. AN INTERESTING SOLUTION IS EVIDENT IN
THE HRRR WITH CONVECTION FORMING OUT NORTHWEST OF LUBBOCK AND MOVING
SLOWLY THIS WAY...BUT PERHAPS NOT REACHING THE CITY. GIVEN THAT
THIS SOLUTION IS SOMEWHAT REPRESENTED IN LOCATION / THOUGH NOT
COVERAGE / HAVE EXPANDED POPS SOUTHWARD THIS EVENING. LIKE THE PAST
SEVERAL NIGHTS...LOW-END SEVERE STORMS WILL BE POSSIBLE WITH
CONDITIONS WANING TUESDAY MORNING FOR A WHILE. A BACK DOOR FRONT
IS INDICATED BY GUIDANCE AND WITH THE ALREADY PLENTIFUL CONVECTION
ACROSS THE PANHANDLE...PREFER THE QUICKER SOLUTION AND AS SUCH
HAVE BROUGHT THE BOUNDARY...AND ASSOCIATED INCREASED RAIN
CHANCES...INTO OUR CWFA DURING THE AFTERNOON ON TUESDAY.
LONG TERM...
MID-LEVEL PATTERN WILL CONTINUE TO AMPLIFY INTO THE EXTENDED WITH
STRONGER NW FLOW AND DEEP LAYER SHEAR ACROSS THE SOUTH PLAINS TUE
PM INTO WED IN THE WAKE OF THE FRONTAL BOUNDARY. THIS SCENARIO
SHOULD SUPPORT CONTINUED WIDESPREAD PRECIP CHANCES AS MOST MODELS
SUPPORT SOME Q-G LIFT ALONG WITH FRONTOGENETICAL FORCING CENTERED
OVER ERN NM INTO THE WRN SOUTH PLAINS. FAVORABLE 700MB THETA-E AXIS ALSO
REMAINS IN PLACE WITH PWATS INCREASING THROUGH THE FIRST COUPLE OF
DAYS OF THE EXTENDED PERIOD AS WELL. ONE LIMITING FACTOR FOR
CONSIDERATION FOR INCREASED COVERAGE WITH TIME IS THE INSTABILITY
DURING THE DAY WED. EXPECT CONSIDERABLE CLOUDINESS AND UPSLOPE
FLOW TO INHIBIT WARMING AND SUBSTANTIAL CAPE HOWEVER DEEPLY MOIST
ATMOSPHERE SHOULD AID DEVELOPMENT LOCALLY. ADDITIONAL HEATING
ACROSS EASTERN NM COUPLED WITH AMPLE SHEAR SHOULD HELP SOME
ACTIVITY TO ORGANIZE AND MOVE ACROSS THE WESTERN HALF OF THE AREA
AGAIN LATE EVENING AND OVERNIGHT WED NIGHT. SUBTLE SHORTWV
ACTIVITY TRAVERSING THE NW FLOW WILL HELP SUSTAIN AFTN STORMS THU
IN CONTINUED LIGHT UPSLOPE FLOW. ONCE AGAIN UNCAPPED ATMOSPHERE WILL
ALLOW SHOWERS TO FORM EARLY AND PREVENT THINGS FROM BECOMING TOO
UNSTABLE WITH SEVERE THREAT LIMITED OUTSIDE OF SOME HEAVY RAINERS.
FLOW TURNS MORE NRLY ON FRI AS RIDGE BUILDS FROM 4 CORNERS INTO
MONTANA. GFS AND EURO BOTH SUPPORT UPPER LOW DROPPING INTO THE MO
VALLEY ON SAT TO MAINTAIN SOME LIFT WITHIN REMNANT MOIST AXIS ON
EASTERN SIDE OF THE RIDGE. WITH CONTINUED ISOLD-SCT CONVECTION
POSSIBLE HAVE KEPT POPS GOING INTO THE WEEKEND WITH LITTLE TO NO
OVERALL WARMING TREND.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 89 65 81 61 / 20 30 50 50 40
TULIA 65 89 67 80 62 / 20 30 50 50 40
PLAINVIEW 66 91 68 80 63 / 20 30 40 50 40
LEVELLAND 70 94 68 84 65 / 10 20 30 50 40
LUBBOCK 70 93 69 83 65 / 10 20 30 50 40
DENVER CITY 72 92 65 88 66 / 10 10 20 40 40
BROWNFIELD 73 94 70 86 66 / 10 10 20 50 40
CHILDRESS 72 96 69 84 67 / 20 40 50 50 30
SPUR 75 97 74 86 68 / 20 20 30 50 40
ASPERMONT 76 99 75 89 69 / 20 20 30 50 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/16
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
754 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL PASS ACROSS THE REGION TODAY. THEN A LARGE HIGH
PRESSURE SYSTEM WILL BUILD IN OVER THE OHIO VALLEY AND THE MID
ATLANTIC TONIGHT AND WEDNESDAY...BRINGING SOMEWHAT COOLER AND
DRIER WEATHER. THIS WILL LAST LATE INTO THE WEEK BEFORE MOISTURE
STARTS TO SLOWLY RETURN BY THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 658 AM EDT TUESDAY...
UPDATED POPS/WEATHER AND RAINFALL FOR NEXT FEW HOURS PER
CONCENTRATED AREA OF HEAVY RAIN SHOWERS AND ISOLATED THUNDER
ACROSS MT ROGERS REC AREA AND FAR NW NC. LATEST HRRR HAS
REASONABLE HANDLE ON THIS AND TAKES IT ALL THE WAY INTO PIEDMONT
THROUGH 13Z. THINK THIS MAY BE A LITTLE FAST AND MAY NOT SURVIVE
FULLY INTACT THAT FAR EAST...BUT DID INCREASE POPS OUT OF AHEAD OF
IT AND BROUGHT LIKELY INTO FOOTHILLS AND TOWARD LYH A LITTLE
EARLIER. WILL NEED CONSTANT TWEAKING. RAINFALL RATES ARE FROM 2-3
INCHES PER HOUR IN STRONGER RETURNS...BUT IT IS MOVING AT ABOUT 40
MPH. ANOTHER WAVE OF ACTIVITY WILL ENTER FROM EASTERN KY THOUGH BY
800 AM...SO MANY AREAS WILL NEED TO BE WATCHED CAREFULLY FOR FLASH
FLOOD POTENTIAL THROUGH AT LEAST THE MORNING HOURS.
PREV DISCUSSION AS OF 440 AM EDT TUESDAY...
SURFACE COOL FRONT CONTINUES TO SLOWLY MAKE ITS WAY SOUTHEASTWARD
THROUGH THE OHIO VALLEY EARLY THIS MORNING WITH WAVES RIPPLING
ALONG IT IN THE UPPER LEVELS. THIS IS RESULTING IN CONTINUED AREAS
OF ORGANIZED BUT FAIRLY SHALLOW CONVECTION FROM UPSTATE NY AND
PA...SOUTHWESTWARD ALONG THE WEST SIDE OF THE APPALACHIANS AND
INTO CENTRAL KY. AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS HAVE
GENERALLY BEEN WEAKENING AS THEY MOVE INTO THE WESTERN PORTIONS OF
OUR FCST AREA WITH WEST FLOW AND LITTLE TO NO INSTABILITY
REMAINING. ONE WAVE MAY BRING A MORE ORGANIZED AREA INTO THE WEST
DURING THE FRIST PART OF THE DAYLIGHT HOURS JUST AHEAD OF FRONTAL
BOUNDARY. FRONT WILL THEN PUSH ACROSS DURING THE DAY...BUT AS
USUAL NOT CLEANLY...WITH SOME LEE SIDE TROUGHING ALREADY EVIDENT
THIS MORNING...IT MAY SHIFT INTO THE PIEDMONT THIS
AFTERNOON...WITH DEEPER CONVECTION FIRING ACROSS THE EASTERN
PORTIONS OF OUR AREA OR MAYBE EVEN OFF TO THE EAST BY MID TO LATE
AFTERNOON. WITH TIMING OF POPS...GENERALLY FOLLOWED A BLEND OF THE
06Z RAP13 AND HIGH RES WRF-ARW FROM 00Z.
DO NOT THINK THERE WILL BE MANY BREAKS IN CLOUD COVER SO
INSTABILITY REMAINS WEAK TO MODEST...MAYBE 1000-1500 SFC BASED
MOST AREAS...WITH UP TO 2000 J/KG IN THE EAST IF WE CAN GET A FEW
BREAKS IN CLOUDS. DO NOT SEE MUCH IN THE WAY OF SEVERE WEATHER
POTENTIAL GIVEN VERY MOIST AIRMASS AND NOT ESPECIALLY STEEP LAPSE
RATES. LOCALLY HEAVY RAIN WILL BE MAIN CONCERN AGAIN...AND GIVEN
RAINFALL LAST EVENING AND SOME CONTINUED LIGHT TO MODERATE
OVERNIGHT IN FAR WEST...BIGGEST THREAT FOR ANY FLASH FLOODING
REMAINS IN THE WEST...EVEN THOUGH THERE IS SOME QUESTION AS TO
WHETHER ANY DEEPER CONVECTION CAN SUSTAIN ITSELF OR GET GOING
DURING THE MORNING HOURS BEFORE THE FRONT PUSHES THROUGH THE
MOUNTAINS. WILL KEEP THE FLASH FLOOD WATCH GOING THROUGH THE
DAY...ALTHOUGH AREAS IN THE FOOTHILLS VERY MARGINAL...AND WE WILL
LIKELY BE ABLE TO CANCEL EARLY AS BELIEVE ANY ORGANIZED CONVECTION
AND HEAVIER RAINFALL RATES WILL SHIFT EAST BY EARLY TO MID
AFTERNOON.
FRONT PUSHES WELL EAST BY EARLY EVENING IF NOT SOONER..QUICKLY
LOWERING THREAT OF SHWRS/STORMS ACROSS THE ENTIRE AREA BEFORE
MIDNIGHT. KEPT CHC POP GOING IN EAST UNTIL MIDNIGHT...BUT MY
FEELING IS THIS MAY MOVE OUT EVEN QUICKER. ALSO THERE IS LINGERING
LOW LEVEL MOISTURE ON WEST SLOPES BEHIND FRONT AND MAYBE SOME
SPRINKLES OR DRIZZLE IS POSSIBLE FOR A WHILE THIS EVENING BACK
THERE AS WELL...SO KEPT LOW CHC POPS INTO EARLY EVENING AS WELL.
TEMPERATURE WISE...AM LEANING TO COOLER MET GUIDANCE FOR HIGHS GIVEN
EXPECTED CLOUD COVER...AND EVEN NUDGED DOWN A DEG OR TWO FROM
THERE. ONE AREA THAT MAY END SEEING A LITTLE MORE SUN IS FAR
SOUTHEAST AND IF THERE ARE MORE THAN JUST A COUPLE HOURS OF IT
DURING TEH AFTERNOON THE LOW 90S TEMPS THE MAV IS ADVERTISING
COULD BE REALIZED...SO WILL HAVE TO WATCH THIS. TONIGHT WE MAY SEE
THE FIRST 50S IN THE WEST IN QUITE SOME TIME WITH LOWER DEW PTS
MOVING IN AND SOME CLEARING.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...
LOOKING AT MAINLY DRY CONDITIONS FOR WEDNESDAY...POSSIBLY WITH A FEW
LINGERING SHOWERS ACROSS OUR NORTHWEST WIND UPSLOPE AREAS DURING THE
MORNING...AS CANADIAN HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
UPPER MIDWEST. THIS AIRMASS WILL BRING A SIGNIFICANT COOL DOWN TO OUR
AREA...WITH AFTERNOON HIGHS RANGING FROM 7 TO 9 DEGREES BELOW NORMAL
FOR MID AUGUST. HIGH PRESSURE WILL SHIFT EAST DURING THE DAY...AND
THEN BUILD SOUTHWARD ALONG THE EASTERN FACE OF THE APPALACHIANS
WEDNESDAY NIGHT...WHICH WILL SHIFT OUR WINDS TO A NORTHEASTERLY
DIRECTION.
THURSDAY WILL REMAIN RELATIVELY DRY AS WELL...ALTHOUGH MAY SEE A
LITTLE LIGHT RAIN ENTER THE NORTH CAROLINA MOUNTAINS AND THE
MOUNTAIN EMPIRE ON THURSDAY AS WINDS AROUND THE HIGH PRESSURE WEDGE
PICK UP MOISTURE FROM UPPER LEVEL DISTURBANCES RIDING ALONG THE COLD
FRONT STALLED WELL TO OUR SOUTH. RAINFALL WILL REMAIN ISOLATED
HOWEVER...AND WOULD NOT MAKE ANY CHANGES TO OUTDOOR PLANS AT THIS
POINT. THE COOL EASTERLY FLOW WILL AGAIN KEEP TEMPERATURES SEVERAL
DEGREES BELOW NORMAL...WITH MOST AREAS HOLDING IN THE 70S FOR
AFTERNOON HIGHS.
WILL SEE A BETTER RETURN OF MOISTURE FOR FRIDAY AS A DEEP UPPER
LEVEL TROUGH MOVES INTO THE CENTRAL MISSISSIPPI RIVER VALLEY. WHILE
HIGH PRESSURE WILL REMAIN IN PLACE IN THE LOW LEVELS...WINDS ALOFT
ALONG THE EASTERN SEABOARD WILL BECOME INCREASINGLY SOUTHWESTERLY AS
THE TROUGH AMPLIFIES. THIS UPPER FLOW WOULD BE FAVORABLE FOR
CARRYING DISTURBANCES ACROSS THE CAROLINAS...WHICH WOULD POTENTIALLY
TRIGGER SPOTTY SHOWERS AND THUNDERSTORMS FOR OUR AREA SOUTH OF
INTERSTATE 81.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...
AS WE PROGRESS INTO THE WEEKEND...CURRENT MODEL TRENDS OFFER A
STALLED DEEPENING LOW OVER THE CENTRAL U.S. WITH THE LOW ALONG THE
GULF BEING TRANSPORTED NORTHWARD ON THE EAST SIDE OF THE CENTRAL
CONUS TROUGH. THIS WOULD ALLOW FOR BETTER DYNAMICS AND MOISTURE FLOW
ACROSS THE REGION. THIS WILL LEAD TO BETTER CHANCE OF LIGHT TO
MODERATE RAIN OVER THE AREA THROUGH SATURDAY...AND THEN BETTER
CHANCES OF SHOWERS AND SOME THUNDERSTORMS BY SUNDAY. WHILE ACTIVITY
MAY TAPER OFF A BIT ON MONDAY...THE CENTRAL CONUS TROUGH WOULD STILL
BE TO OUR WEST...AND BE A FEATURE TO POTENTIALLY INFLUENCE OUR
WEATHER PAST DAY 7.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 750 AM EDT TUESDAY...
PERIODS OF IFR IN HEAVY SHOWERS AND ISOLATED THUNDERSTORMS THIS
MORNING ACROSS THE WEST...WILL GIVE WAY TO MAINLY VFR CONDITIONS
BY AFTERNOON BUT STILL WITH SCATTERED SHOWERS AND STORMS AND BRIEF
MVFR TO IFR CONDITIONS WITH STORMS AS A COLD FRONT PUSHES THROUGH
THE REGION THROUGH THE MIDDLE OF THE DAY TODAY...EXITING THE FAR
SOUTHEAST BY EARLY EVENING. SOME PATCHY FOG AT DAN AND LYH THIS
MORNING SHOULD ALSO IMPROVE TO VFR BY MID MORNING...YET STILL WITH
BRIEF IFR CONDITIONS POSSIBLE IF A THUNDERSTORM MOVES ACROSS THE
AIRPORT. KEPT THUNDER MENTIONED IN VICINITY SINCE NOT CONFIDENT IN
HOW WIDESPREAD COVERAGE WILL BE OUT EAST.
BY LATE TODAY THE FRONT WILL SHIFT SLOWLY SOUTHEAST AND TURN THE
WINDS TO THE WNW BY AFTERNOON. BY EARLY EVENING...DRIER AIR WILL
BE FILTERING IN AND LINGERING SHOWERS WILL PUSH EAST OF
DAN/LYH...BY 02Z OR EARLIER. SOME LINGERING LOW LEVEL MOISTURE IN
TEH FAR WEST COULD RESULT KIN IFR CIGS OVERNIGHT...AS WELL AS
PATCHY IFR FOG AT VALLEY AIRPORTS...BUT BY WED VFR SHOULD DOMINATE
THROUGH MOST OF THE REST OF WEEK UNDER DRY HIGHI PRESSURE.
&&
.HYDROLOGY...
AS OF 355 PM EDT MONDAY...
NO CHANGES TO FLASH FLOOD WATCH. SOME AREAS RECEIVED 3"+ OVER THE
MOUNTAIN EMPIRE OF SW VA...INCLUDING THE RICHLANDS AREA LAST
EVENING.
MORE HEAVIER DOWNPOURS ARE POSSIBLE AGAIN TODAY...MAINLY IN THE
MORNING WEST AND AFTERNOON EAST.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR VAZ007-009>017-032.
NC...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NCZ001>003-018-019.
WV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR WVZ042>045.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK
SHORT TERM...NF
LONG TERM...DS/NF
AVIATION...SK/WP
HYDROLOGY...AMS/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
700 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL PASS ACROSS THE REGION ON TODAY. THEN A LARGE
HIGH PRESSURE SYSTEM WILL BUILD IN OVER THE OHIO VALLEY AND THE
MID ATLANTIC TONIGHT AND WEDNESDAY...BRINGING SOMEWHAT COOLER AND
DRIER WEATHER. THIS WILL LAST LATE INTO THE WEEK BEFORE MOISTURE
STARTS TO SLOWLY RETURN BY THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 658 AM EDT TUESDAY...
UPDATED POPS/WEATHER AND RAINFALL FOR NEXT FEW HOURS PER
CONCENTRATED AREA OF HEAVY RAIN SHOWERS AND ISOLATED THUNDER
ACROSS MT ROGERS REC AREA AND FAR NW NC. LATEST HRRR HAS
REASONABLE HANDLE ON THIS AND TAKES IT ALL THE WAY INTO PIEDMONT
THROUGH 13Z. THINK THIS MAY BE A LITTLE FAST AND MAY NOT SURVIVE
FULLY INTACT THAT FAR EAST...BUT DID INCREASE POPS OUT OF AHEAD OF
IT AND BROUGHT LIKELY INTO FOOTHILLS AND TOWARD LYH A LITTLE
EARLIER. WILL NEED CONSTANT TWEAKING. RAINFALL RATES ARE FROM 2-3
INCHES PER HOUR IN STRONGER RETURNS...BUT IT IS MOVING AT ABOUT 40
MPH. ANOTHER WAVE OF ACTIVITY WILL ENTER FROM EASTERN KY THOUGH BY
800 AM...SO MANY AREAS WILL NEED TO BE WATCHED CAREFULLY FOR FLASH
FLOOD POTENTIAL THROUGH AT LEAST THE MORNING HOURS.
PREV DISCUSSION AS OF 440 AM EDT TUESDAY...
SURFACE COOL FRONT CONTINUES TO SLOWLY MAKE ITS WAY SOUTHEASTWARD
THROUGH THE OHIO VALLEY EARLY THIS MORNING WITH WAVES RIPPLING
ALONG IT IN THE UPPER LEVELS. THIS IS RESULTING IN CONTINUED AREAS
OF ORGANIZED BUT FAIRLY SHALLOW CONVECTION FROM UPSTATE NY AND
PA...SOUTHWESTWARD ALONG THE WEST SIDE OF THE APPALACHIANS AND
INTO CENTRAL KY. AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS HAVE
GENERALLY BEEN WEAKENING AS THEY MOVE INTO THE WESTERN PORTIONS OF
OUR FCST AREA WITH WEST FLOW AND LITTLE TO NO INSTABILITY
REMAINING. ONE WAVE MAY BRING A MORE ORGANIZED AREA INTO THE WEST
DURING THE FRIST PART OF THE DAYLIGHT HOURS JUST AHEAD OF FRONTAL
BOUNDARY. FRONT WILL THEN PUSH ACROSS DURING THE DAY...BUT AS
USUAL NOT CLEANLY...WITH SOME LEE SIDE TROUGHING ALREADY EVIDENT
THIS MORNING...IT MAY SHIFT INTO THE PIEDMONT THIS
AFTERNOON...WITH DEEPER CONVECTION FIRING ACROSS THE EASTERN
PORTIONS OF OUR AREA OR MAYBE EVEN OFF TO THE EAST BY MID TO LATE
AFTERNOON. WITH TIMING OF POPS...GENERALLY FOLLOWED A BLEND OF THE
06Z RAP13 AND HIGH RES WRF-ARW FROM 00Z.
DO NOT THINK THERE WILL BE MANY BREAKS IN CLOUD COVER SO
INSTABILITY REMAINS WEAK TO MODEST...MAYBE 1000-1500 SFC BASED
MOST AREAS...WITH UP TO 2000 J/KG IN THE EAST IF WE CAN GET A FEW
BREAKS IN CLOUDS. DO NOT SEE MUCH IN THE WAY OF SEVERE WEATHER
POTENTIAL GIVEN VERY MOIST AIRMASS AND NOT ESPECIALLY STEEP LAPSE
RATES. LOCALLY HEAVY RAIN WILL BE MAIN CONCERN AGAIN...AND GIVEN
RAINFALL LAST EVENING AND SOME CONTINUED LIGHT TO MODERATE
OVERNIGHT IN FAR WEST...BIGGEST THREAT FOR ANY FLASH FLOODING
REMAINS IN THE WEST...EVEN THOUGH THERE IS SOME QUESTION AS TO
WHETHER ANY DEEPER CONVECTION CAN SUSTAIN ITSELF OR GET GOING
DURING THE MORNING HOURS BEFORE THE FRONT PUSHES THROUGH THE
MOUNTAINS. WILL KEEP THE FLASH FLOOD WATCH GOING THROUGH THE
DAY...ALTHOUGH AREAS IN THE FOOTHILLS VERY MARGINAL...AND WE WILL
LIKELY BE ABLE TO CANCEL EARLY AS BELIEVE ANY ORGANIZED CONVECTION
AND HEAVIER RAINFALL RATES WILL SHIFT EAST BY EARLY TO MID
AFTERNOON.
FRONT PUSHES WELL EAST BY EARLY EVENING IF NOT SOONER..QUICKLY
LOWERING THREAT OF SHWRS/STORMS ACROSS THE ENTIRE AREA BEFORE
MIDNIGHT. KEPT CHC POP GOING IN EAST UNTIL MIDNIGHT...BUT MY
FEELING IS THIS MAY MOVE OUT EVEN QUICKER. ALSO THERE IS LINGERING
LOW LEVEL MOISTURE ON WEST SLOPES BEHIND FRONT AND MAYBE SOME
SPRINKLES OR DRIZZLE IS POSSIBLE FOR A WHILE THIS EVENING BACK
THERE AS WELL...SO KEPT LOW CHC POPS INTO EARLY EVENING AS WELL.
TEMPERATURE WISE...AM LEANING TO COOLER MET GUIDANCE FOR HIGHS GIVEN
EXPECTED CLOUD COVER...AND EVEN NUDGED DOWN A DEG OR TWO FROM
THERE. ONE AREA THAT MAY END SEEING A LITTLE MORE SUN IS FAR
SOUTHEAST AND IF THERE ARE MORE THAN JUST A COUPLE HOURS OF IT
DURING TEH AFTERNOON THE LOW 90S TEMPS THE MAV IS ADVERTISING
COULD BE REALIZED...SO WILL HAVE TO WATCH THIS. TONIGHT WE MAY SEE
THE FIRST 50S IN THE WEST IN QUITE SOME TIME WITH LOWER DEW PTS
MOVING IN AND SOME CLEARING.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...
LOOKING AT MAINLY DRY CONDITIONS FOR WEDNESDAY...POSSIBLY WITH A FEW
LINGERING SHOWERS ACROSS OUR NORTHWEST WIND UPSLOPE AREAS DURING THE
MORNING...AS CANADIAN HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
UPPER MIDWEST. THIS AIRMASS WILL BRING A SIGNIFICANT COOL DOWN TO OUR
AREA...WITH AFTERNOON HIGHS RANGING FROM 7 TO 9 DEGREES BELOW NORMAL
FOR MID AUGUST. HIGH PRESSURE WILL SHIFT EAST DURING THE DAY...AND
THEN BUILD SOUTHWARD ALONG THE EASTERN FACE OF THE APPALACHIANS
WEDNESDAY NIGHT...WHICH WILL SHIFT OUR WINDS TO A NORTHEASTERLY
DIRECTION.
THURSDAY WILL REMAIN RELATIVELY DRY AS WELL...ALTHOUGH MAY SEE A
LITTLE LIGHT RAIN ENTER THE NORTH CAROLINA MOUNTAINS AND THE
MOUNTAIN EMPIRE ON THURSDAY AS WINDS AROUND THE HIGH PRESSURE WEDGE
PICK UP MOISTURE FROM UPPER LEVEL DISTURBANCES RIDING ALONG THE COLD
FRONT STALLED WELL TO OUR SOUTH. RAINFALL WILL REMAIN ISOLATED
HOWEVER...AND WOULD NOT MAKE ANY CHANGES TO OUTDOOR PLANS AT THIS
POINT. THE COOL EASTERLY FLOW WILL AGAIN KEEP TEMPERATURES SEVERAL
DEGREES BELOW NORMAL...WITH MOST AREAS HOLDING IN THE 70S FOR
AFTERNOON HIGHS.
WILL SEE A BETTER RETURN OF MOISTURE FOR FRIDAY AS A DEEP UPPER
LEVEL TROUGH MOVES INTO THE CENTRAL MISSISSIPPI RIVER VALLEY. WHILE
HIGH PRESSURE WILL REMAIN IN PLACE IN THE LOW LEVELS...WINDS ALOFT
ALONG THE EASTERN SEABOARD WILL BECOME INCREASINGLY SOUTHWESTERLY AS
THE TROUGH AMPLIFIES. THIS UPPER FLOW WOULD BE FAVORABLE FOR
CARRYING DISTURBANCES ACROSS THE CAROLINAS...WHICH WOULD POTENTIALLY
TRIGGER SPOTTY SHOWERS AND THUNDERSTORMS FOR OUR AREA SOUTH OF
INTERSTATE 81.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...
AS WE PROGRESS INTO THE WEEKEND...CURRENT MODEL TRENDS OFFER A
STALLED DEEPENING LOW OVER THE CENTRAL U.S. WITH THE LOW ALONG THE
GULF BEING TRANSPORTED NORTHWARD ON THE EAST SIDE OF THE CENTRAL
CONUS TROUGH. THIS WOULD ALLOW FOR BETTER DYNAMICS AND MOISTURE FLOW
ACROSS THE REGION. THIS WILL LEAD TO BETTER CHANCE OF LIGHT TO
MODERATE RAIN OVER THE AREA THROUGH SATURDAY...AND THEN BETTER
CHANCES OF SHOWERS AND SOME THUNDERSTORMS BY SUNDAY. WHILE ACTIVITY
MAY TAPER OFF A BIT ON MONDAY...THE CENTRAL CONUS TROUGH WOULD STILL
BE TO OUR WEST...AND BE A FEATURE TO POTENTIALLY INFLUENCE OUR
WEATHER PAST DAY 7.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 200 AM EDT TUESDAY...
BETWEEN 06Z AND 12Z THERE WILL BE ANOTHER WAVE OF SHOWERS WITH
MODERATE RAINFALL AND ISOLATED THUNDER MOVING FROM KY INTO
SOUTHEAST WV AND LIKELY TO IMPACT BLF/LWB AGAIN WITH PERIODS OF
IFR CONDITIONS. LEFT MENTION OF THUNDER OUT OF LWB HOWEVER AS
LINGER WEAK INSTABILITY CONFINED A LITTLE FARTHER SOUTH. MORE
SHALLOW CONVECTION ORGANIZATION CONTINUES TO DEVELOP UPSTREAM SO
THERE MAY NOT BE TOO MANY BREAKS IN PRECIP ACTIVITY...AND FOG MAY
NOT BE AS DENSE AS ONCE EXPECTED AT LWB UNLESS SOME REAL BREAKS IN
PRECIP CAN OCCUR LATE. THUS MAKING FOR TROUBLESOME TAF
FORECAST ESPECIALLY AT THESE SITES. FARTHER EAST EXPECT A FEW
SHOWERS MAY REACH BCB/ROA/LYH BY 08Z TO 09Z BUT CIGS SHOULD REMAIN
VFR OR MVFR...WITH EXCEPTION OF BCB...BUT LIKELY TO GET SOME IFR
FOG FARTHER EAST LATE TONIGHT. OVERALL...EXPECT THE USUAL HARD TO
PIN DOWN FLUCTUATION BETWEEN IFR/LIFR TO VFR AT TIMES THROUGH
EARLY MORNING GIVEN THE TROPICAL AIRMASS AND THREAT OF SHOWERS.
FOR TUESDAY THE FRONT SHIFTS SLOWLY SOUTHEAST AND TURNS THE WINDS
TO THE WNW BY AFTERNOON. EXPECT MOST OF THE CONVECTION IN THE
MORNING IN THE WEST TO TRANSFER EAST OF THE MOUNTAINS IN THE
AFTERNOON. COVERAGE FOR SHOWERS SHOULD BE 50/50 AT LEAST IF NOT
MORE BUT KEPT THUNDER OUT OF THE PREDOMINANT GROUP FOR NOW...BUT
LEFT IN VICINITY. MAINLY VFR CONDITIONS FOR THE DAY...EXCEPT IN
THE CASE THAT ANY HEAVIER RAIN OR STORMS MOVE RIGHT OVER AN
AIRPORT.
THE COLD FRONT...AND ASSOCIATED HIGH PRESSURE...WILL LIKELY BE
STRONG ENOUGH TO PUSH THE TROPICAL AIRMASS OUT OF THE AREA FOR A
COUPLE OF DAYS...BRINGING A GOOD OPPORTUNITY FOR WIDESPREAD VFR
WEATHER THAT MAY LAST OVER MUCH OF THE AREA LATER TUESDAY NIGHT INTO
THURSDAY BEFORE MOISTURE BEGINS TO RETURN NORTHWARD ON THE BACK SIDE
OF THE HIGH LATE IN THE WEEK. ONE EXCEPTION WILL BE AT THE
SOUTHEASTERN WV TERMINAL FORECAST SITES WHERE RETURN TO VFR
WEATHER WITH NO FLIGHT RESTRICTIONS MAY BE DELAYED UNTIL MID TO
LATE WEDNESDAY DUE TO COOL UPSLOPING WINDS AND LINGERNIG LOW
CLOUDS AND PERHAPS EVEN SOME DRIZZLE TUES NIGHT.
&&
.HYDROLOGY...
AS OF 355 PM EDT MONDAY...
NO CHANGES TO FLASH FLOOD WATCH. SOME AREAS RECEIVED 3"+ OVER THE
MOUNTAIN EMPIRE OF SW VA...INCLUDING THE RICHLANDS AREA.
MORE HEAVIER DOWNPOURS ARE POSSIBLE AGAIN OVERNIGHT AND TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR VAZ007-009>017-032.
NC...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NCZ001>003-018-019.
WV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR WVZ042>045.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK
SHORT TERM...NF
LONG TERM...DS/NF
AVIATION...CF/SK/WP
HYDROLOGY...AMS/SK
AREA FORECAST DISCUSSION
NWS SPOKANE WA
245 PM PDT Tue Aug 13 2013
.SYNOPSIS...
A warming and drying trend arrives Wednesday and lingers into
Thursday. A weak cold front will move into the Cascades Thursday
afternoon then trickle across the Inland NW Friday and Saturday.
This will bring a chance for light showers and a few thunderstorms
along with near normal temperatures and locally breezy winds.
Seasonal temperatures and dry conditions will return Sunday into
early next week.
&&
.DISCUSSION...
Tonight: It appears as though there are only a couple of spots of
concern for thunderstorms for the remainder of the afternoon into
the evening. The Blue Mountains, the Camas Prairie and the
mountains of the Idaho Panhandle. Synoptic scale forcing is weak
region wide. As of 2 PM, a small scale vorticity max was moving
out of the southern Idaho Panhandle into western Montana. This
mesoscale feature should enhance the thunderstorm potential in
northwest Montana this evening. The RUC surface CAPE/CIN analysis
suggests that Shoshone, Boundary, Bonner and Pend O`Reille
counties are essentially uncapped with as much as 2000 J/KG of
surface based instability. The HRRR suggests that a few
thunderstorms will develop between 4 PM and 6 PM over central and
southern Shoshone county. It will be interesting to see if
convection will develop in the wake of the departing vorticity
center. Forecasters usually imply that there is subsidence behind
these small vort maxes to suppress convection. I am more confident
that a storm or two will develop over the Blues and over the peaks
near Bonners Ferry. The threat for thunderstorms will decrease
quickly this evening with the loss of surface heating. By 8 PM,
look for clearing skies region-wide.
Wednesday: Hot temperatures will return on Wednesday with low to
mid 90s common over the Inland Northwest. Both the NAM and GFS
forecast a bit of moisture at 700mb Wednesday morning, advancing
northward through the Columbia Basin. This will probably not be
enough moisture to produce high based showers, but we will need to
monitor satellite and radar imagery tonight for the potential of
some light, high based showers in the morning. Otherwise, large
scale subsidence under a building upper ridge axis will cause
temperatures to warm a good 3 to 6 degrees tomorrow over today.
/GKoch
Wednesday night through Saturday: Models are in strong agreement
that the trof of low pressure currently spinning over the Gulf of
AK will eject east and pass through the Inland NW ushering a cool
front across the region. This will bring a chance for showers and
a few thunderstorms along with a cooling trend, and a slight
increase in winds.
The cool front will be reaching the Cascades around mid to late
afternoon on Thursday then slowly trickle across Ern Wa and Nrn
ID during the next 48 hours...barely clearing ID and Ern OR by
Saturday afternoon. This is exceptionally slower then models were
forecasting 24 hours ago but does make sense based on how the
upper-level jet parallels the front. So what does this mean? Well,
there are a few items of interest that could alter the forecast.
All models agree that there will be a rich but narrow fetch of
subtropical moisture absorbed into the system...running
along/ahead of the frontal boundary. So increased clouds are a
definite but given the slow movement of the front and weakening
thermal structure of the front upon crossing into Ern WA...lift
along the frontal boundary will be mediocre. As such,
precipitation along the front will be light and generally in a
slow, top-down saturation regime. This does not mean the region
will escape dry for better chances for precipitation will come in
two other forms.
The first will focus on smaller shortwaves swinging around the parent
low and tracking SW to NE along the baroclinic/frontal zone. GFS
is most robust with these waves but other models do show these
features in one form or another and looking at current water
vapor, the first wave that will swing through on Thursday is
evident via sharp area of darkening near 46N/155W. These are the
waves that tend to bring a quick burst of showers along slow
moving frontal systems that start off looking rather dry as this
did on yesterday`s models. The second feature will be convection
(ie thunderstorms). This pattern does not look overly impressive
or unstable for thunderstorms but it is August and timing will be
key. We did maintain a small threat for thunder over the Cascades
Thursday aftn however clouds should thickening throughout the day
and I am not real confident we can achieve the 500 J/kg of sb CAPE
showing up on the models Thursday aftn in this area. A better
threat for thunderstorms will come across Ern WA and ID Panhandle
Friday afternoon and Saturday as the front trickles this
way/stalls and works in conjunction with peak heating. Model
soundings indicate a modest layer of CIN for most locations away
from the far northern mountains so the lift along the front will
be necessary to lift these parcels and utilize the instability
but given the weakening nature of the front, we kept the main
threat for thunderstorms across the mountains or slightly
downstream of the steering flow.
All things considered, models are generally indicating light pcpn
with this event with the exception of the more robust GFS which
has a few quarter inch bull-eyes...one over the NE Mtns and
second near the Blue Mtns...and for reasoning above...the forecast
may need to trend wetter as these two features become more
apparent. /sb
Saturday Night through Tuesday Night: As the trough that brought
the chance for showers and thunderstorms to much of the region
exits to the east Saturday evening into Sunday we will see slight
chance remain for some showers and isolated t-storms for mainly
the northern ID Panhandle. As this pushes to the east our region
will be left with a general westerly flow. Most of the moisture
with this flow will remain to our north keeping the chance for
precipitation low. Also with the zonal flow we will not see many
changes in our temperatures with most areas sitting in the 80s for
highs and upper 50s to lower 60s for overnight lows. Winds will
die off from the breezy conditions we saw Saturday and look to
remain seasonal for the early part of next week. Models are
hinting at a wave dropping down from the Gulf of Alaska during the
middle part of next week...but with consistency between the
solutions lacking we will hold off on any major changes to the
forecast that far out for now. /Fliehman
&&
.AVIATION...
18Z TAFS: VFR conditions are expected through 14/18z. The only
weather of consequence will be the potential for showers and
isolated thunderstorms over the Idaho panhandle. The thunderstorms
look like they will miss KCOE to the east, but updates will be
likely if the precipitation moves further west. All activity
expected to die off after sunset. ty
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 62 92 66 89 65 85 / 10 10 0 0 10 20
Coeur d`Alene 57 92 60 90 60 85 / 10 10 0 0 10 20
Pullman 51 92 54 90 57 86 / 0 10 0 0 10 20
Lewiston 64 100 66 98 66 94 / 10 0 0 0 0 10
Colville 53 95 57 93 59 87 / 0 10 0 10 20 20
Sandpoint 51 89 53 90 56 87 / 10 10 0 0 10 20
Kellogg 56 91 59 90 57 89 / 20 0 0 0 10 20
Moses Lake 59 95 64 93 65 90 / 10 10 0 10 10 10
Wenatchee 64 93 69 91 67 89 / 10 10 0 10 10 20
Omak 60 95 63 93 63 90 / 0 10 10 10 10 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
604 PM CDT WED AUG 14 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 333 PM CDT WED AUG 14 2013
AT 3 PM...THE SATELLITE LOOP SHOWED A BROKEN DECK OF 7 TO 8K FOOT
CLOUDS ACROSS THE FORECAST AREA. THE RAP SEEMS TO HAVE THE BEST
HANDLE ON THESE CLOUDS AND THEY SHOW THAT THESE CLOUDS WILL
GRADUALLY DISSIPATE THIS EVENING.
FOR LATE TONIGHT AND THURSDAY MORNING...THE BUFKIT SOUNDINGS SHOW
THAT THERE WILL BE A DEEP LAYER /UP TO 775 MB/ OF LIGHT WINDS
ACROSS THE AREA. WHILE THIS WOULD BE FAVORABLE FOR THE DEVELOPMENT
OF VALLEY FOG. THE NAM/WRF...GFS...AND RAP CONTINUE TO SHOW THAT
THE TEMPERATURE/DEW POINT SPREAD WILL REMAIN AT OR ABOVE 1C. IN
ADDITION...THE GFS AND NAM/WRF SUGGEST THAT THERE COULD BE STILL
SOME CLOUDS AROUND THE REGION. AS A RESULT...WENT WITH PATCHY
VALLEY FOG FOR THE MISSISSIPPI RIVER AND ITS TRIBUTARIES...AND
AREAS OF FOG IN THE WISCONSIN RIVER VALLEY.
ON THURSDAY...THE MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH
WILL MOVE SOUTHEAST ACROSS SOUTHERN AND WESTERN IOWA. WEAK 925 AND
850 MB MOISTURE TRANSPORT NORTHEAST OF THIS SYSTEM WILL AID IN THE
DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND SOUTHWEST
WISCONSIN. WITH ML CAPES LESS THAN 400 J/KG AND VERY WEAK 0-3 KM
AND 0-6 KM...NONE OF THESE THUNDERSTORMS ARE EXPECTED TO BECOME
SEVERE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 333 PM CDT WED AUG 14 2013
ON FRIDAY...THE 925 MB AND 850 MB WEAK MOISTURE TRANSPORT AND 700
TO 600 MB FRONTOGENESIS REMAINS SOUTHWEST OF THE FORECAST AREA.
IN ADDITION...THERE IS VERY LITTLE SURFACE MOISTURE CONVERGENCE
ACROSS THE AREA. WITH THE MESO MODELS IN AGREEMENT WITH THE GEM
AND ECMWF THAT THE AREA WILL REMAIN DRY...REMOVED THE
PRECIPITATION CHANCES FOR THIS TIME PERIOD.
ON BOTH THURSDAY AND FRIDAY NIGHTS...BOTH THE GFS AND NAM/WRF
SOUNDINGS SHOW A DEEP LAYER /UP TO AT LEAST 800 MB/ OF LIGHT
WINDS. THIS WOULD BE VERY FAVORABLE FOR THE DEVELOPMENT OF VALLEY
FOG. HOWEVER THEY ALSO HINT THAT THERE MAY BE SOME CLOUDS AROUND
THE REGION. ANOTHER FACTOR THAT MAY BE A LIMITING FACTOR IS THE
AMOUNT OF MOISTURE IN THE BOUNDARY LAYER. THE NAM/WRF HAS MUCH
MORE MOISTURE THAN THE GFS. DUE TO THIS UNCERTAINTY...JUST
INTRODUCED PATCHY TO AREAS OF VALLEY FOG ON BOTH NIGHTS.
FROM MONDAY THROUGH WEDNESDAY...THE MODELS ARE CONTINUING TO
STRUGGLE WITH THE 500 MB UPPER AIR PATTERN. THE GFS AND GEM ARE
SHOWING THAT THE UPPER LEVEL RIDGE REMAINS LONGER TO THE WEST THAN
THE ECMWF. AS A RESULT...THE GFS AND GEM ARE FASTER AT MOVING THE
COLD FRONT SOUTHEAST INTO THE FORECAST AREA. MEANWHILE THE ECMWF
HAS THE FRONT REMAINING WELL NORTHWEST OF THE FORECAST AREA. SINCE
THE MODELS HAVE BEEN TRENDING SLOWER DURING THIS TIME PERIOD...THE
CONSENSUS OF OUR OFFICE AND THE SURROUNDING WFOS TO KEEP MOST OF
THE FORECAST AREA DRY DURING THIS TIME FRAME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 604 PM CDT WED AUG 14 2013
FORECAST CONCERN IS ON VALLEY FOG POTENTIAL AT LSE. SCT-BKN HIGH
BASED CUMULUS PERSISTS AROUND BOTH TAF SITES. SOME OF THESE ARE
DIURNALLY DRIVEN AND ARE DISSIPATING NOW WITH LOSS OF HEATING...
HOWEVER...OTHERS ARE PERSISTING. VARIOUS MODELS...RAP...NAM...
GFS...ALL DEPICT THAT THE MOISTURE AROUND 7000 FT AGL WILL STICK
AROUND THROUGH THE NIGHT AND THROUGH THE DAY THURSDAY AT BOTH
SITES. THIS MOISTURE SHOULD CONTINUE TO MANIFEST ITSELF AS SCT-BKN
HIGH BASED CUMULUS. THEREFORE...DESPITE A LIGHT WIND PROFILE UP
TO 5000 FT AGL OR HIGHER AT LSE THAT WOULD BE FAVORABLE FOR VALLEY
FOG...THESE CLOUDS GREATLY THROW FOG INTO QUESTION.
THEREFORE...HAVE LEFT VALLEY FOG OUT OF THE LSE FORECAST. SHOULD
MORE CLEARING OCCUR...THE CONCERN FOR VALLEY FOG WILL INCREASE.
OTHERWISE...VFR CONDITIONS CONTINUE THROUGH THURSDAY WITH PERHAPS
JUST A SLIGHT CHANCE FOR AN AFTERNOON SHOWER AT RST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1216 PM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENTLY...LOOKING AT MOSAIC RADAR...OUR CWFA IS PRETTY MUCH ECHO
FREE WITH A LINE OF THUNDERSTORMS PUSHING SOUTHEAST IN CENTRAL
NEBRASKA AT 1 AM THIS MORNING. FRONTAL BOUNDARY STILL LAYS UP
ALONG THE LARAMIE RANGE THIS MORNING...EXTENDING NORTHWEST INTO
CENTRAL MONTANA. TO OUR NORTH...A COMPLEX OF THUNDERSTORMS LAYS ACROSS
EASTERN MONTANA JUST EAST OF THE FRONT.
IT REMAINS TO BE SEEN WHAT THAT LINE OF THUNDERSTORMS OVER
NEBRASKA WILL DO TO OUR LOW LEVEL MOISTURE. IT HAS CAUSED WINDS TO
BECOME MORE SOUTHWESTERLY AND THEREFORE A LITTLE DRIER IN THE
PANHANDLE SO FAR. LATEST 11U-3.9U SATELLITE IMAGERY HAS YET TO
SHOW THE ANTICIPATED STRATUS DEVELOPING YET.
THE MORNING SHOULD START OFF DRY WITH INCREASING SHOWERS AND
THUNDERSTORMS DEVELOPING BY NOON. LATEST HRRR COMPOSITE
REFLECTIVITY FORECAST HAS SHOWERS DEVELOPING OVER THE MOUNTAINS TO
THE WEST OF CHEYENNE BY 17Z AND REALLY INCREASING IN COVERAGE
AFTER 19Z. THIS CORRESPONDS WELL WITH THE 00Z ECMWF FORECAST FOR
THE UPPER VORT MAX TO MOVE THROUGH THE UPPER RIDGE THIS AFTERNOON.
FORECAST STORM MOTIONS THIS AFTERNOON ON THE NAM SOUNDINGS SHOW
STORMS TO BE ALMOST STATIONARY. SOME LOCATIONS ARE GOING TO SEE
SOME HEAVY RAINFALL...LIKELY LEADING TO SOME FLASH FLOODING.
CONFIDENCE NO HIGH ON WHERE THESE THUNDERSTORMS ARE GOING TO
DEVELOP...SO WILL HOLD OFF ON ANY WATCHES. BUT DO EXPECT US TO BE
ISSUING FLASH FLOOD WARNINGS FOR SOME AREAS TODAY.
UPPER VORT MAX STAYS WITH US THROUGH THE OVERNIGHT HOURS
TONIGHT...FINALLY EXITING SOUTHEAST WEDNESDAY AFTERNOON. DID KEEP
FAIRLY HIGH POPS GOING TONIGHT THROUGH AT LEAST MIDNIGHT...THEN
PICKING UP AGAIN WEDNESDAY AFTERNOON WITH DAYTIME HEATING.
PATTERN CHANGE THEN BEGINS WEDNESDAY NIGHT INTO THURSDAY AS THE
ECMWF BUILDS THE UPPER LEVEL RIDGE. WITH THE BUILDING RIDGE...THE
DRIER AIR OVER UTAH AND SOUTHERN COLORADO WILL FILTER INTO THE
AREA DURING THE DAY THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 242 AM MDT TUE AUG 13 2013
ALL LONG RANGE MODELS IN AGREEMENT...SHOWING A BREAK IN THE
PERSISTENT MOIST WEATHER PATTERN ACROSS THE FORECAST AREA LATE
THIS WEEK. A DRYING TREND WILL CONTINUE THROUGH SATURDAY WITH
WARMER TEMPERATURES IN THE 80S AND LOW 90S EXPECTED. THE WARMEST
DAY WILL LIKELY BE SATURDAY AS THE RIDGE AXIS SHIFTS EASTWARD INTO
THE PLAINS...WITH HIGHS IN THE MID 80S TO MID 90S
EXPECTED...WARMEST ACROSS THE LOWER ELEVATIONS BELOW 5000 FEET.
KEPT POP BELOW 10 PERCENT WITH LIMITED CLOUD COVER. KEPT
TEMPERATURES A FEW DEGREES BELOW MOS FOR NOW...SINCE IT IS UNCLEAR
HOW THE CURRENT SOIL MOISTURE WILL IMPACT TEMPERATURES AND
HUMIDITY. WITH LIGHT WINDS EXPECTED...DO NOT BELIEVE THE NEAR
SURFACE MOISTURE WILL BE ADVECTED EASTWARD AS THAT QUICK.
PRECIPITATION CHANCES WILL RETURN TO THE AREA BY LATE SUNDAY AND
INTO MONDAY OF NEXT WEEK AS A FAST MOVING PACIFIC TROUGH PUSHES
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SOME COOLER AIR WILL PUSH
INTO THE REGION AS WELL WITH HIGH TEMPERATURES 5 TO 10 DEGREES
COOLER COMPARED TO FRIDAY/SATURDAY. INCREASED POP BETWEEN 20 TO 40
PERCENT FOR SHOWERS AND TSTORMS SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1210 PM MDT TUE AUG 13 2013
MAINLY VFR CONDITIONS THROUGH THE TAF PERIOD. SCATTERED SHOWERS
AND TSTMS WILL DEVELOP IN SOUTHEAST WY BY AROUND 20Z AND THEN
SPREAD EASTWARD ACROSS THE PLAINS THROUGH THE EVENING. SOME OF THE
STORMS COULD PRODUCE HEAVIER DOWNPOURS AND BRIEF MVFR VIS. SHOWERS
COULD LINGER OVER THE PANHANDLE THROUGH THE EARLY MORNING ON
WEDNESDAY. WINDS SHOULD GENERALLY REMAIN BELOW 10-15 KTS...HOWEVER
GUSTY WINDS TO 30 KTS COULD OCCUR IN THE VICINITY OF STORMS.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENT THINKING IS THAT FIRE WEATHER CONCERNS WILL BE MINOR TODAY
AND WEDNESDAY AS MONSOONAL MOISTURE OVER WYOMING WILL CREATE
WIDESPREAD WETTING RAINS FOR MOST LOCATIONS. DRIER AIR BEGINS TO
MOVE INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY. AFTERNOON
HUMIDITIES FORECAST TO BE IN THE SINGLE DIGITS ACROSS CARBON
COUNTY THURSDAY AFTERNOON. WINDS ARE EXPECTED TO REMAIN FAIRLY
LIGHT THOUGH AND SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...FINCH
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
546 AM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENTLY...LOOKING AT MOSAIC RADAR...OUR CWFA IS PRETTY MUCH ECHO
FREE WITH A LINE OF THUNDERSTORMS PUSHING SOUTHEAST IN CENTRAL
NEBRASKA AT 1 AM THIS MORNING. FRONTAL BOUNDARY STILL LAYS UP
ALONG THE LARAMIE RANGE THIS MORNING...EXTENDING NORTHWEST INTO
CENTRAL MONTANA. TO OUR NORTH...A COMPLEX OF THUNDERSTORMS LAYS ACROSS
EASTERN MONTANA JUST EAST OF THE FRONT.
IT REMAINS TO BE SEEN WHAT THAT LINE OF THUNDERSTORMS OVER
NEBRASKA WILL DO TO OUR LOW LEVEL MOISTURE. IT HAS CAUSED WINDS TO
BECOME MORE SOUTHWESTERLY AND THEREFORE A LITTLE DRIER IN THE
PANHANDLE SO FAR. LATEST 11U-3.9U SATELLITE IMAGERY HAS YET TO
SHOW THE ANTICIPATED STRATUS DEVELOPING YET.
THE MORNING SHOULD START OFF DRY WITH INCREASING SHOWERS AND
THUNDERSTORMS DEVELOPING BY NOON. LATEST HRRR COMPOSITE
REFLECTIVITY FORECAST HAS SHOWERS DEVELOPING OVER THE MOUNTAINS TO
THE WEST OF CHEYENNE BY 17Z AND REALLY INCREASING IN COVERAGE
AFTER 19Z. THIS CORRESPONDS WELL WITH THE 00Z ECMWF FORECAST FOR
THE UPPER VORT MAX TO MOVE THROUGH THE UPPER RIDGE THIS AFTERNOON.
FORECAST STORM MOTIONS THIS AFTERNOON ON THE NAM SOUNDINGS SHOW
STORMS TO BE ALMOST STATIONARY. SOME LOCATIONS ARE GOING TO SEE
SOME HEAVY RAINFALL...LIKELY LEADING TO SOME FLASH FLOODING.
CONFIDENCE NO HIGH ON WHERE THESE THUNDERSTORMS ARE GOING TO
DEVELOP...SO WILL HOLD OFF ON ANY WATCHES. BUT DO EXPECT US TO BE
ISSUING FLASH FLOOD WARNINGS FOR SOME AREAS TODAY.
UPPER VORT MAX STAYS WITH US THROUGH THE OVERNIGHT HOURS
TONIGHT...FINALLY EXITING SOUTHEAST WEDNESDAY AFTERNOON. DID KEEP
FAIRLY HIGH POPS GOING TONIGHT THROUGH AT LEAST MIDNIGHT...THEN
PICKING UP AGAIN WEDNESDAY AFTERNOON WITH DAYTIME HEATING.
PATTERN CHANGE THEN BEGINS WEDNESDAY NIGHT INTO THURSDAY AS THE
ECMWF BUILDS THE UPPER LEVEL RIDGE. WITH THE BUILDING RIDGE...THE
DRIER AIR OVER UTAH AND SOUTHERN COLORADO WILL FILTER INTO THE
AREA DURING THE DAY THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 242 AM MDT TUE AUG 13 2013
ALL LONG RANGE MODELS IN AGREEMENT...SHOWING A BREAK IN THE
PERSISTENT MOIST WEATHER PATTERN ACROSS THE FORECAST AREA LATE
THIS WEEK. A DRYING TREND WILL CONTINUE THROUGH SATURDAY WITH
WARMER TEMPERATURES IN THE 80S AND LOW 90S EXPECTED. THE WARMEST
DAY WILL LIKELY BE SATURDAY AS THE RIDGE AXIS SHIFTS EASTWARD INTO
THE PLAINS...WITH HIGHS IN THE MID 80S TO MID 90S
EXPECTED...WARMEST ACROSS THE LOWER ELEVATIONS BELOW 5000 FEET.
KEPT POP BELOW 10 PERCENT WITH LIMITED CLOUD COVER. KEPT
TEMPERATURES A FEW DEGREES BELOW MOS FOR NOW...SINCE IT IS UNCLEAR
HOW THE CURRENT SOIL MOISTURE WILL IMPACT TEMPERATURES AND
HUMIDITY. WITH LIGHT WINDS EXPECTED...DO NOT BELIEVE THE NEAR
SURFACE MOISTURE WILL BE ADVECTED EASTWARD AS THAT QUICK.
PRECIPITATION CHANCES WILL RETURN TO THE AREA BY LATE SUNDAY AND
INTO MONDAY OF NEXT WEEK AS A FAST MOVING PACIFIC TROUGH PUSHES
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SOME COOLER AIR WILL PUSH
INTO THE REGION AS WELL WITH HIGH TEMPERATURES 5 TO 10 DEGREES
COOLER COMPARED TO FRIDAY/SATURDAY. INCREASED POP BETWEEN 20 TO 40
PERCENT FOR SHOWERS AND TSTORMS SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE 12Z TAF ISSUANCE)
LOW CIGS AND PATCHY FOG HAVE STRUGGLED TO DEVELOP ACROSS WESTERN
NEBRASKA EARLY THIS MORNING. KCDR WILL CONTINUE WITH A LOW CIG
AROUND 500 TO 1000 FEET AGL EARLY THIS MORNING BEFORE THE CLOUDS
LIFT AND DISSIPATE BY 14Z. ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS IS EXPECTED...FIRST DEVELOPING OVER SOUTHEAST WYOMING
EARLY THIS AFTERNOON WITH VCTS AT KRWL AND KLAR BY 19Z...AND THEN
MOVING EASTWARD ACROSS THE HIGH PLAINS BY MID TO LATE AFTERNOON.
THUNDERSTORMS MAY CONTAIN ERRATIC GUSTY WINDS UP TO 45 KNOTS...HEAVY
RAINFALL...AND FREQUENT LIGHTNING BEFORE DISSIPATING LATE THIS
EVENING.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENT THINKING IS THAT FIRE WEATHER CONCERNS WILL BE MINOR TODAY
AND WEDNESDAY AS MONSOONAL MOISTURE OVER WYOMING WILL CREATE
WIDESPREAD WETTING RAINS FOR MOST LOCATIONS. DRIER AIR BEGINS TO
MOVE INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY. AFTERNOON
HUMIDITIES FORECAST TO BE IN THE SINGLE DIGITS ACROSS CARBON
COUNTY THURSDAY AFTERNOON. WINDS ARE EXPECTED TO REMAIN FAIRLY
LIGHT THOUGH AND SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
346 AM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENTLY...LOOKING AT MOSAIC RADAR...OUR CWFA IS PRETTY MUCH ECHO
FREE WITH A LINE OF THUNDERSTORMS PUSHING SOUTHEAST IN CENTRAL
NEBRASKA AT 1 AM THIS MORNING. FRONTAL BOUNDARY STILL LAYS UP
ALONG THE LARAMIE RANGE THIS MORNING...EXTENDING NORTHWEST INTO
CENTRAL MONTANA. TO OUR NORTH...A COMPLEX OF THUNDERSTORMS LAYS ACROSS
EASTERN MONTANA JUST EAST OF THE FRONT.
IT REMAINS TO BE SEEN WHAT THAT LINE OF THUNDERSTORMS OVER
NEBRASKA WILL DO TO OUR LOW LEVEL MOISTURE. IT HAS CAUSED WINDS TO
BECOME MORE SOUTHWESTERLY AND THEREFORE A LITTLE DRIER IN THE
PANHANDLE SO FAR. LATEST 11U-3.9U SATELLITE IMAGERY HAS YET TO
SHOW THE ANTICIPATED STRATUS DEVELOPING YET.
THE MORNING SHOULD START OFF DRY WITH INCREASING SHOWERS AND
THUNDERSTORMS DEVELOPING BY NOON. LATEST HRRR COMPOSITE
REFLECTIVITY FORECAST HAS SHOWERS DEVELOPING OVER THE MOUNTAINS TO
THE WEST OF CHEYENNE BY 17Z AND REALLY INCREASING IN COVERAGE
AFTER 19Z. THIS CORRESPONDS WELL WITH THE 00Z ECMWF FORECAST FOR
THE UPPER VORT MAX TO MOVE THROUGH THE UPPER RIDGE THIS AFTERNOON.
FORECAST STORM MOTIONS THIS AFTERNOON ON THE NAM SOUNDINGS SHOW
STORMS TO BE ALMOST STATIONARY. SOME LOCATIONS ARE GOING TO SEE
SOME HEAVY RAINFALL...LIKELY LEADING TO SOME FLASH FLOODING.
CONFIDENCE NO HIGH ON WHERE THESE THUNDERSTORMS ARE GOING TO
DEVELOP...SO WILL HOLD OFF ON ANY WATCHES. BUT DO EXPECT US TO BE
ISSUING FLASH FLOOD WARNINGS FOR SOME AREAS TODAY.
UPPER VORT MAX STAYS WITH US THROUGH THE OVERNIGHT HOURS
TONIGHT...FINALLY EXITING SOUTHEAST WEDNESDAY AFTERNOON. DID KEEP
FAIRLY HIGH POPS GOING TONIGHT THROUGH AT LEAST MIDNIGHT...THEN
PICKING UP AGAIN WEDNESDAY AFTERNOON WITH DAYTIME HEATING.
PATTERN CHANGE THEN BEGINS WEDNESDAY NIGHT INTO THURSDAY AS THE
ECMWF BUILDS THE UPPER LEVEL RIDGE. WITH THE BUILDING RIDGE...THE
DRIER AIR OVER UTAH AND SOUTHERN COLORADO WILL FILTER INTO THE
AREA DURING THE DAY THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 242 AM MDT TUE AUG 13 2013
ALL LONG RANGE MODELS IN AGREEMENT...SHOWING A BREAK IN THE
PERSISTENT MOIST WEATHER PATTERN ACROSS THE FORECAST AREA LATE
THIS WEEK. A DRYING TREND WILL CONTINUE THROUGH SATURDAY WITH
WARMER TEMPERATURES IN THE 80S AND LOW 90S EXPECTED. THE WARMEST
DAY WILL LIKELY BE SATURDAY AS THE RIDGE AXIS SHIFTS EASTWARD INTO
THE PLAINS...WITH HIGHS IN THE MID 80S TO MID 90S
EXPECTED...WARMEST ACROSS THE LOWER ELEVATIONS BELOW 5000 FEET.
KEPT POP BELOW 10 PERCENT WITH LIMITED CLOUD COVER. KEPT
TEMPERATURES A FEW DEGREES BELOW MOS FOR NOW...SINCE IT IS UNCLEAR
HOW THE CURRENT SOIL MOISTURE WILL IMPACT TEMPERATURES AND
HUMIDITY. WITH LIGHT WINDS EXPECTED...DO NOT BELIEVE THE NEAR
SURFACE MOISTURE WILL BE ADVECTED EASTWARD AS THAT QUICK.
PRECIPITATION CHANCES WILL RETURN TO THE AREA BY LATE SUNDAY AND
INTO MONDAY OF NEXT WEEK AS A FAST MOVING PACIFIC TROUGH PUSHES
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SOME COOLER AIR WILL PUSH
INTO THE REGION AS WELL WITH HIGH TEMPERATURES 5 TO 10 DEGREES
COOLER COMPARED TO FRIDAY/SATURDAY. INCREASED POP BETWEEN 20 TO 40
PERCENT FOR SHOWERS AND TSTORMS SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 944 PM MDT MON AUG 12 2013
THROUGH 07Z...ISOLATED SHOWERS EAST OF A DOUGLAS TO CHEYENNE LINE.
FROM 10Z TO 16Z...AREAS OF LOW CLOUDS AND FOG AT NEBRASKA
AERODROMES WITH LOCALIZED IFR AND MVFR...VFR ELSEWHERE. AFTER 20Z
TUESDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
PRODUCING LOCALIZED MVFR.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENT THINKING IS THAT FIRE WEATHER CONCERNS WILL BE MINOR TODAY
AND WEDNESDAY AS MONSOONAL MOISTURE OVER WYOMING WILL CREATE
WIDESPREAD WETTING RAINS FOR MOST LOCATIONS. DRIER AIR BEGINS TO
MOVE INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY. AFTERNOON
HUMIDITIES FORECAST TO BE IN THE SINGLE DIGITS ACROSS CARBON
COUNTY THURSDAY AFTERNOON. WINDS ARE EXPECTED TO REMAIN FAIRLY
LIGHT THOUGH AND SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1209 AM CDT Thu Aug 15 2013
.SHORT TERM...(This Evening through Friday Afternoon)
Issued at 257 PM CDT WED AUG 14 2013
The main focus in the short-term remains a series of shortwave
troughs sinking southeastward across the Plains this evening,
Thursday, and into early Friday. Showers and isolated storms have
developed over portions of eastern Nebraska in association with a
wave currently pushing southeast toward the forecast area; however,
ongoing precipitation will continue to move into fairly dry air this
evening, and may struggle against entrainment. Additionally, upper-
level flow may push the main area of precipitation more east than
south, keeping the bulk of any falling precipitation in central and
southern Iowa. Short-term precipitation trends from the HRRR have
been fairly consistent today, and also generally limit the south and
eastward expansion of showers for this evening and tonight. For now,
have kept PoPs very low and confined to far northwest Missouri prior
to 06z, then have begun to increase chances in the NW to account for
possible regeneration as the low-level jet kicks up early Thursday
morning.
The next system will follow on the heels of tonight`s as it drops
down from eastern Montana on Thursday. Models continue to indicate
that the reinforcement of the eastern trough by a second upper low,
and the retrograding of a broad upper high, will result in more
meridional flow across the Plains for Thursday and Friday. This
subtle change will send the second wave a bit west of the forecast
area, keeping the better rain chances mainly across portions of
central and eastern Kansas. Have left some slight to low-end chance
PoPs mainly across the western tier or two of counties on Thursday
afternoon and Thursday night, but these could likely be cut further
if model trends continue in this direction. Any precipitation that
does brush the area will sink southward on Friday morning, leaving
behind quiet conditions by Friday afternoon.
Temperatures through the period will remain ~10 degrees below normal
as cool air continues to filter down the trough and into the eastern
Plains and Ohio River valley, with highs generally topping out in
the upper 70s to lower 80s, and lows in the 50s to lower 60s under
surface high pressure.
.LONG TERM...(Friday Evening through Wednesday)
Issued at 257 PM CDT WED AUG 14 2013
A quiet medium range forecast for the Central Plains as mid-level
ridging currently building over the Rockies begins to move
eastward. Despite the increasing heights, Saturday will likely
remain below seasonal normals as surface and low-level winds remain
light to southeast. By Sunday, we`ll begin to see a steady climb
back to or even above normal as winds turn southerly and warmer air
begins to advect northward.
The first half of next week will again feature quiet conditions as
mid-level flow remains weak. Temperatures will have a chance to
return to the 90 degree mark by Tuesday and Wednesday, a rare feat
this August.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1154 PM CDT WED AUG 14 2013
Still some uncertainty about whether showers will make it far enough
south to affect KMCI/KMKC...as there may not be enough ascent to
adequately saturate the column. As of now it looks as though the best
chance for actual precipitation will be further north toward KSTJ and
points north. Regardless of showery activity expect VFR conditions
to be predominant through the entire period. Will continue to monitor
and amend as necessary.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Laflin
LONG TERM...Dux
AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS HASTINGS NE
431 AM CDT THU AUG 15 2013
...SVR TSTMS POSSIBLE THIS AFTN-EVNG THEN WE HAVE A GORGEOUS DRY
WEEKEND IN STORE FOR OUTDOOR ACTIVITIES...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 431 AM CDT THU AUG 15 2013
ALOFT: NW FLOW WILL CONT OVER THE PLAINS THRU TNGT...WITHIN AN
AMPLIFIED ROCKIES RIDGE/ERN USA TROF LGWV PATTERN. WV IMAGERY SHOWED
A WELL-DEFINED SHRTWV TROF OVER ERN MT/NERN WY. THIS TROF WILL CONT
MOVING SE TODAY AND WILL BE LOCATED ALONG THE KS/OK BORDER BY
DAYBREAK FRI.
SFC: 1024 MB HIGH PRES WAS OVER THE OH VALLEY EARLY THIS MRNG. THIS
HIGH WILL ESSENTIALLY EXPAND E INTO THE MID-ATLANTIC...REMAINING
FAIRLY STATIONARY. THE MAIN POLAR FRONT WILL ALSO REMAIN STALLED
WELL S OF THE FCST AREA...OVER TX AND THE GULF COAST STATES. AN E-W
ORIENTED SFC TROF WAS NOTED OVER NEB /ROUGHLY ALONG I-80/ AND ITS
WRN END WAS ATTACHED TO A WEAK LEE-SIDE LOW OVER THE PANHANDLE. THIS
TROF IS FCST TO REMAIN IN PLACE /UNLESS IT BECOMES MODULATED OR
PARTIALLY DESTROYED BY ON-GOING CONVECTION THIS MRNG/. MEANWHILE...
THE LEE-SIDE LOW WILL STRENGTHEN AND SLIDE DOWN THE HIGH PLAINS TO
BE NEAR PUB BY SUNSET.
FCST FOR TODAY IS ESSENTIALLY VARIABLE CLOUDS WITH APPARENTLY A
COUPLE DIFFERENT OPPORTUNITIES FOR TSTMS. CONVECTIVE EVOLUTION
REMAINS COMPLEX AND UNCERTAIN...ESPECIALLY THIS AFTN/EVNG DUE TO THE
ON-GOING CLUSTER OF TSTMS AND ITS INFLUENCE ON FUTURE DEVELOPMENTS.
EARLY THIS MRNG: FOR THE 3RD MRNG IN A ROW WE HAVE A SMALL MCS
APPROACHING AND EXPECT IT TO AFFECT AREAS W AND S OF THE TRI-CITIES
BETWEEN 5-9 AM. THIS WEEK HAS BEEN EXCELLENT FOR MUCH-NEEDED
RAINFALL.
THE 05Z HI-RES RAP AND 00Z WRF FROM THE SD SCHOOL OF MINES AND TECH
LOOK EXCELLENT COMPARED TO REALITY AND HOW THIS MRNG WILL EVOLVE.
THE SMALL MCS WILL CONT INTO THE FCST AREA...PROBABLY WEAKENING WITH
TIME. A FEW SHWRS/POSSIBLE THUNDER? WILL ALSO CONT TO DEVELOP WITHIN
THE LLJ INDUCED WAA/ISENTROPIC ASCENT AHEAD OF THE MCS.
WHAT HAPPENS AFTER THIS MCS DEPARTS REMAINS UP FOR GRABS. THE
REMNANT MCV WILL BE SE OF OUR KS COUNTIES THIS AFTN AND WILL NOT BE
A FACTOR. THE TRAILING OUTFLOW /AND ANY POSSIBLE DIFFERENTIAL
HEATING BOUNDARIES/ WILL NEED TO BE WATCHED FOR CONVECTIVE
INITIATION THIS AFTN...AS WELL AS WHATEVER IS LEFT OF THE E-W
ORIENTED SFC TROF. THE HI-RES RAP AND THE SYNOPTIC-SCALE MODELS FCST
TSTMS OVER THE PANHANDLE THIS MRNG /POSSIBLY THE SMALL TSTM
CLUSTERS CURRENTLY ON-GOING OVER ERN WY/NWRN SD?/ AND THEN INCREASE
IN COVERAGE THIS AFTN AS THEY HEAD SE INTO THE FCST AREA.
WHILE PWAT/S ON 00Z SOUNDINGS ARE ONLY NEAR NORMAL...THE FCST AREA
LIES IN A RIBBON OF DECENT LOW-LVL MSTR /DWPTS LOW-MID 60S/. THE NAM
HIGH TEMPS WERE TOO WARM GIVEN EXPECTED RAINFALL AND CLOUD COVER
TODAY. SO USED THE 03Z SREF MEAN MLCAPE WHICH SUGGESTS 1500-2500
J/KG WITH THE GREATEST VALUES S AND W OF THE TRI-CITIES. THAT COULD
BE TOO HIGH GIVEN THAT A PORTION OF THE INSOLATION THAT OCCURS THIS
AFTN WILL GO TO EVAPORATING RAINFALL...NOT TO MENTION LEFTOVER
CLOUDINESS WHICH WILL RETARD DIURNAL HEATING.
OVERALL TROPOSPHERIC WINDS WILL BE WEAK...BUT DIRECTIONAL SHEAR
/WITH SFC AND MID-LVL WINDS 180 APART/ WILL CONTRIBUTE TO 0-6 KM
SHEAR OF 30-40 KTS /HIGHEST OVER N-CNTRL KS/.
INDIVIDUAL CELL MOVEMENT WILL BE SE AT 15-20 KTS. ANY MULTICELL
CLUSTERS THAT FORM COULD MOVE UP TO 40 KTS THREATENING SOME WIND
DAMAGE. IF A SUPERCELL OR TWO FORMS...MOVEMENT WOULD BE SSW AROUND
20 KTS. HODOGRAPHS WILL BE NEARLY A STRAIGHT-LINE SUGGESTING
SUPERCELL SPLITS A POSSIBILITY.
MAIN THREATS: HAIL TO 1.75" AND STRAIGHT-LINE WINDS TO 60 MPH. AN
ISOLATED TORNADO CAN/T BE COMPLETELY RULED OUT W OF A LINE FROM
LEXINGTON NEB-HOLDREGE-OSBORNE KS...EITHER SUPERCELLULAR WITH 0-1
KM SRH OF 80-100 M2/S2 OR A NON-SUPERCELL TOR ASSOCIATED WITH ANY
BOUNDARIES.
TNGT: SVR TSTMS WILL PROBABLY BE ON-GOING DURING THE EVNG HRS...BUT
SHOULD BE S-SE OF THE FCST AREA BY MIDNGT. WINDS PROBABLY TURN
CALM /OR NEARLY CALM/ AFTER 2 AM. THIS THREATENS SOME FOG WHERE
SKIES CLEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 431 AM CDT THU AUG 15 2013
GUIDANCE SUGGESTS UPPER LEVEL RIDGING WILL PERSIST OVER THE WESTERN
CONUS THROUGH SUNDAY OR MONDAY...BEFORE MOVING EAST INTO PORTIONS OF
THE CENTRAL CONUS BY MID NEXT WEEK. AS A RESULT...NORTH TO
NORTHWESTERLY MID TO UPPER LEVEL FLOW IS EXPECTED OVER THE CENTRAL
PLAINS THROUGH MUCH OF THE LONG TERM FORECAST PERIOD...WITH THIS
FLOW SUBSTANTIALLY DECREASING IN INTENSITY AS THE UPPER LEVEL RIDGE
AXIS MOVES NEAR THE REGION BY EARLY TO MID NEXT WEEK. GIVEN THE
ANTICIPATED LACK IN KINEMATIC FORCING DURING THE EXTENDED FORECAST
PERIOD...AS SUGGESTED BY GUIDANCE...CHANCES FOR PRECIPITATION APPEAR
AS THOUGH THEY WILL REMAIN LOW. THERE SEEMS TO BE PRETTY GOOD
AGREEMENT BETWEEN THE NAM...EC...AND SREF-MEAN OF LINGERING
OVERNIGHT CONVECTION PERHAPS IMPACTING SOUTHERN AND EASTERN PORTIONS
OF OUR CWA FOR A TIME FRIDAY MORNING AND GIVEN THE ~20% POPS
INHERITED FROM THE PREVIOUS FORECAST...OPTED TO KEEP THE
SLIGHT-CHANCE POPS GOING FOR OUR SOUTH AND EAST 12-18Z FRIDAY.
BEYOND 18Z FRIDAY...THE ONLY CHANCE AT OBSERVING MEASURABLE
PRECIPITATION ACROSS THE AREA APPEARS AS THOUGH IT WILL REMAIN
RELEGATED TO THE LATTER PART OF THE LONG TERM FORECAST PERIOD AS THE
AXIS OF A 25-35KT 850MB JET STREAK SETS UP OVER THE AREA. LOW LEVEL
THERMAL ADVECTION ALONG THIS JET STREAK AXIS COULD PROMOTE ISOLATED
TO SCATTERED PRECIPITATION ACROSS THE AREA...A SOLUTION SUPPORTED BY
QPF FIELDS FROM THE OPERATIONAL GFS AND EC...ALTHOUGH IT IS WORTH
MENTIONING THAT THESE MODELS DO NOT AGREE ON WHICH DAYS OR WHICH
LOCATIONS ARE BETTER FAVORED FOR OBSERVING PRECIPITATION. ALLBLEND
RESPONDED BY PROVIDING ~20% POPS TO MUCH OF THE CWA MONDAY NIGHT
THROUGH WEDNESDAY AND GIVEN THE AFOREMENTIONED GUIDANCE...FELT THESE
POPS WERE JUSTIFIED AND THUS WERE LEFT UNCHANGED FOR THE MOST PART.
LITTLE CHANGE IN THE LOW LEVEL AIRMASS SHOULD PRESENT SIMILAR
TEMPERATURES ACROSS OUR AREA FRIDAY AND SATURDAY. PERSISTENT
SOUTHERLY LOW LEVEL FLOW AND RESULTANT THERMAL ADVECTION HOWEVER
SHOULD THEN ALLOW FOR A WARMING TREND DURING THE EARLY TO MID PART
OF NEXT WEEK. AS A RESULT...AFTERNOON HIGHS IN THE UPPER 70S TO LOW
80S ARE CURRENTLY FORECAST FRIDAY AND SATURDAY...WITH HIGHS CLIMBING
INTO THE MID TO UPPER 80S AND EVENTUALLY THE LOWER 90S TO FINISH OUT
THE LONG TERM FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CDT THU AUG 15 2013
REST OF TNGT: REMOVED FOG AND LOW CIGS FROM THE TAF BASED ON
LBF/OAX SOUNDINGS AS WELL AS WIND AND DWPT TRENDS FROM YESTERDAY
AFTN. EXPECT VFR CIGS MAY GO SCT AT TIMES. THERE IS A CLUSTER OF
TSTMS OVER THE NEB PANHANDLE THAT WILL NEED TO BE MONITORED FOR
POSSIBLE INSERTION INTO THE TAF TOWARD DAWN. S WINDS UNDER 10 KTS.
THU: LOW-END VFR CIGS SHOULD INCREASE TO MID-LVL CIGS FROM THE
REMNANTS OF NEARBY TSTM CLUSTER. BY 18Z...CURRENT EXPECTATION IS
FOR SCT VFR CU TO DEVELOP WITH CB POSSIBLE AFTER 21Z. THERE IS A
LOW PROBABILITY FOR 1 INCH HAIL AND G50 KTS IF THE TERMINAL TAKES
A DIRECT HIT FROM AN AFTN OR EVNG TSTM. S WINDS LESS THAN 10 KTS
WILL BACK TO SE.
THU EVNG: TSTM THREAT SHOULD BE OVER BY 03Z. WE ARE SEEING SIGNALS
OF POSSIBLE IFR FOG AFTER 06Z.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
WX CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1243 AM CDT THU AUG 15 2013
.SYNOPSIS...
ISSUED AT 330 PM CDT WED AUG 14 2013
SHOWER AND THUNDERSTORM ACTIVITY CURRENTLY EXISTS ACROSS NORTH-
CENTRAL NEBRASKA AND IS MOVING EASTWARD SLOWLY. NEBRASKA IS UNDER
NORTHWEST FLOW ALOFT WITH AN UPPER LEVEL WAVE IN EASTERN NEBRASKA
AND ANOTHER OVER MONTANA. LOW LEVEL FLOW IS GENERALLY SOUTHERLY
WITH AN AREA OF LOW PRESSURE OVER THE INTERMOUNTAIN WEST AND HIGH
PRESSURE OVER THE UPPER MISSISSIPPI RIVER VALLEY. A WEAK BOUNDARY
EXISTS ACROSS CENTRAL NEBRASKA...RUNNING FROM HOLT COUNTY
SOUTHWEST TO CHASE COUNTY.
&&
.UPDATE...
ISSUED AT 945 PM CDT WED AUG 14 2013
HAVE ADJUSTED PRECIPITATION CHANCES ACROSS THE AREA NOW THAT
ISOLATED CONVECTION HAS ENDED ACROSS THE AREA...FOR NOW.
HOWEVER...CONVECTIVE COMPLEXES REMAIN ACROSS SOUTHWEST SD AND
NORTHEAST CO. HRRR DOES TRY TO KEEP THE SD COMPLEX TOGETHER LONG
ENOUGH TO MOVE INTO THE PANHANDLE AND INTO THE CENTRAL SANDHILLS.
MID LEVEL LAPSE RATES WOULD SUPPORT SOME ADDITIONAL DEVELOPMENT SO
HAVE LEFT SMALL CHANCES IN FOR NOW. OTHERWISE ADDED SOME PATCHY
FOG EAST OF HIGHWAY 83 WHERE SMALL TEMP/DEW POINT SPREADS EXIST.
UPDATE ISSUED AT 706 PM CDT WED AUG 14 2013
HAVE UPDATED EVENING FCST TO SLIGHTLY ADJUST PRECIP CHANCES.
THUNDERSTORMS SHOWING A QUICK DECREASE IN COVERAGE AND INTENSITY
OVER THE LAST 15 MINS. ADDITIONAL CONVECTION FURTHER WEST WILL
APPROACH THE AREA LATER THIS EVENING...BUT OVERALL MID LEVEL LAPSE
RATES DOES NOT LOOK FAVORABLE AT THIS POINT BUT WILL LOOK FURTHER
INTO THIS. OTHERWISE REMAINDER OF FCST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
THE THUNDERSTORM COMPLEX THAT STARTED OVER THE NORTHEAST HAS
LINGERED THERE TODAY DUE TO A FAVORABLE LOW LEVEL JET...SOME
MODEST ELEVATED CAPE...AND UPPER SUPPORT. A SURFACE BOUNDARY
CURRENTLY RUNS FROM HOLT TO CHASE COUNTIES AND MAY BE THE FOCUS
FOR A FEW THUNDERSTORMS THIS AFTERNOON/EVENING. THE SEVERE THREAT
IS LOW AS DEEP SHEAR IS RUNNING AT 25 TO 30 KTS. AN ISOLATED
SEVERE STORM OR TWO CANNOT BE RULED OUT...HOWEVER. AN UPPER LEVEL
WAVE WILL PUSH INTO THE AREA FROM THE NORTHWEST LATE TONIGHT AND
TOMORROW MORNING. AHEAD OF THIS WAVE...CLOUDS WILL INCREASE AND SO
WILL A LOW LEVEL JET ACROSS WESTERN NEBRASKA. BELIEVE THERE MAY BE
SOME LATE NIGHT THUNDERSTORMS ACROSS THE NORTHWEST LATE IN THE
NIGHT AND EARLY TOMORROW MORNING. THE MAIN UPPER WAVE WILL DRIFT
INTO CENTRAL NEBRASKA BY MIDDAY...AND SO BELIEVE ANY THUNDERSTORM
ACTIVITY WOULD BE PRIMARILY DURING THE LATE MORNING TO AFTERNOON
HOURS. SHEAR TOMORROW IS A LITTLE BETTER...30-35 KTS...ACROSS THE
SOUTH. AS A RESULT...SPC HAS ISSUED A SLIGHT RISK FOR SEVERE
WEATHER ACROSS THAT AREA FOR TOMORROW.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
FORECASTING CHALLENGES ARE LINGERING PRECIPITATION THURSDAY
EVENING...FOG POTENTIAL OVERNIGHT THURSDAY NIGHT INTO FRIDAY
MORNING...THEN TEMPERATURES. WITH RESPECT TO THUNDERSTORM CHANCES
THURSDAY EVENING...THE MODELS ARE A LITTLE FASTER WITH SHORTWAVE
ENERGY DROPPING SOUTH THURSDAY ACROSS THE DAKOTAS AND NEBRASKA.
THIS WILL BRING AN EARLIER END TO PRECIPITATION BY LATE THURSDAY
EVENING IN THE SRN CWA. BEHIND THE EXITING CONVECTION...CLEARING
SKIES...STRONG RADIATIONAL COOLING AND MOIST BOUNDARY LAYER CONDS
MAY LEAD TO THE FORMATION OF FOG OVERNIGHT THURSDAY NIGHT INTO
EARLY FRIDAY MORNING. NAM AND GFS BUFR SOUNDINGS INDICATE A
FAVORABLE ENVIRONMENT FOR FOG FORMATION...AS DOES THE MET AND MAV
GUIDANCE ALONG AND SOUTH OF A LINE FROM BIG SPRINGS TO BARTLETT.
DECIDED TO LEAVE FOG MENTION AS PATCHY ATTM...AS SREF
PROBABILITIES ARE RUNNING AROUND 60 PERCENT FOR VISBYS BLO 1SM.
FOR FRIDAY INTO SUNDAY NIGHT...RIDGING WILL BUILD EAST INTO THE
CENTRAL AND NORTHERN PLAINS...LEADING TO NRLY FLOW ALOFT AND
EFFECTIVELY CUTTING OFF ANY CHANCE FOR PCPN FRIDAY THROUGH SUNDAY.
HIGHS WILL BEGIN TO CLIMB FROM THE LOWER TO MID 80S ON FRIDAY...TO
THE MID 80S TO AROUND 90 BY THE END OF THE WEEKEND. FOR HIGHS AND
LOWS...UTILIZED THE ADJMAV GUIDANCE AS IT HAS HAD THE BEST
VERIFICATION OVER THE PAST COUPLE OF WEEKS AND AVOIDED THE HIGHER
MEX NUMBERS WHICH HAD HIGHS IN THE 90S BY SUNDAY INTO MONDAY.
THINKING ATTM IS THAT THE MEX NUMBERS ARE TOO HIGH GIVEN THE HIGH
DEGREE OF SURFACE MOISTURE ACROSS THE AREA. RIDGING ALOFT WILL
BEGIN TO BREAK DOWN SLIGHTLY EARLY NEXT WEEK AS A DISTURBANCE
TRACKS ACROSS SRN CANADA. THIS FEATURE HAS TRENDED WEAKER COMPARED
TO YESTERDAYS MODEL RUNS...WHICH A...FACILITATES DECREASED POPS
NEXT WEEK...AND B...INCREASED HIGH TEMPS...BOTH OF WHICH WERE
IMPLEMENTED WITH THIS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1243 AM CDT THU AUG 15 2013
SCATTERED TSRA FROM NEAR IEN THROUGH AIA CONTINE TO DROP
SOUTHEAST. FOR THE KLBF TAF SITE CONFIDENCE IS TOO LOW TO INCLUDE
TSRA...BUT WILL BE MONITORED CLOSELY FOR INCLUSION BY NEXT TAF
ISSUANCE. AS FOR KVTN...STORMS TO CROSS WESTERN CHERRY
COUNTY...BUT SHOULD PASS SOUTHWEST OF KVTN TAF LOCATION.
LOW CLOUDS ALREADY IN KVTN AREA. SREF PROBS AND EARLIER HRRR
SUGGESTS VSBYS SHOULD TEMPORARILY GO DOWN TO IFR AFTER 08Z OR SO
NEAR KVTN. ALSO MVFR CIGS AND 5SM BR AT KLBF 09Z-14Z. STORMS
DEVELOPMENT EXPECTED IN THE AFTERNOON AT BOTH TAF SITES WITH
INCLUSION FOR PROB30 20Z-01Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SYNOPSIS...KNUTSVIG
SHORT TERM...KNUTSVIG
LONG TERM...CLB
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1237 AM CDT THU AUG 15 2013
.UPDATE...
ISSUED AT 1237 AM CDT THU AUG 15 2013
POPS HAVE BEEN ADDED/ADJUSTED BASED ON LATEST RADAR TRENDS. AS
WITH THE PAST 2 NGTS ANOTHER SMALL MCS IS ORGANIZING OVER THE
PANHANDLE. THIS CLUSTER IS NOT ASSOCIATED WITH THE LLJ AND WILL
ONLY HAVE ITS OWN COLD POOL TO KEEP IT GOING. NEW SHWRS HAVE
DEVELOP FROM JYR UP TO BVN IN THE LAST HR. THESE ARE LLJ RELATED.
THE 03Z HI-RES RAP HAS ALL THIS HANDLED WELL SO IT WAS USED AS A
FIRST GUESS FOR POPS THRU 12Z. SOME CHANGES IN CLOUD COVER WILL
NEED TO BE MADE BEFORE SUNRISE. OTHERWISE...NO CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
CLOUDS LINGERED ACROSS MUCH OF THE AREA THIS AFTERNOON AND HAS SO
FAR HELPED TO PUT A CAP ON MORE WIDESPREAD CONVECTION. THAT
SAID...INSTABILITY IS BEGINNING TO BUILD...AND WITH SOME NOTABLE
MOISTURE CONVERGENCE AHEAD OF DEVELOPING CONVECTION TO OUR
NORTH...EXPECT THE POTENTIAL FOR ADDITIONAL DEVELOPMENT THROUGH
THE LATE AFTERNOON AND EVENING HOURS. MODELS HAVE NOT HAD A GREAT
HANDLE ON THIS ALL DAY...ALBEIT 12Z WRF AND LATEST HRRR BOTH
ATTEMPTED TO PICK UP ON CONVECTION TO OUR NORTH...TAKING IT
SOUTHWARD THROUGH THE EVENING HOURS. WHILE CONFIDENCE IS NOT
PARTICULARLY HIGH...CONTINUE TO SEE THE POTENTIAL FOR SOME
ADDITIONAL THUNDERSTORM ACTIVITY THROUGH THE EVENING AND INTO THE
OVERNIGHT HOURS AS THERE IS PLENTY OF INSTABILITY TO
TAP...ESPECIALLY WEST OF HIGHWAY 281. THAT SAID...SHEAR IS VERY
WEAK...AND ANY ADDITIONAL STORMS THAT DO DEVELOP ARE NOT EXPECTED
TO BE SEVERE OR WIDESPREAD.
AS WE WORK TOWARDS THURSDAY MORNING AND FOCUS OF INITIAL
CONVECTION SHIFTS SOUTHWARD...COULD SEE SOME PARTIAL
CLEARING...AND WITH LIGHT SOUTHEASTERLY WINDS AND ELEVATED LOW
LEVEL MOISTURE...DECIDED TO INSERT PATCHY FOG INTO THE FORECAST
FOR THE EARLY MORNING HOURS TOMORROW. LATEST HRRR IS INDICATING
POSSIBLY SOME DENSE FOG ACROSS OUR NORTH BY 09Z...BUT WITH
UNCERTAINTY IN TIMING AND AMOUNT OF CLEARING...PATCHY MENTION
SEEMED MORE REASONABLE FOR THE TIME BEING.
AS WE WORK INTO THE DAYTIME HOURS THURSDAY...THE POTENTIAL FOR
SOME STRONG/MARGINALLY SEVERE STORMS WILL BE REALIZED BY EARLY
AFTERNOON AS MODELS ARE PICKING UP ON AN UPPER LEVEL SHORTWAVE
DROPPING DOWN FROM THE NORTH COUPLED WITH THE PRESENCE OF A WEAK
WARM FRONTAL BOUNDARY DRAPED ACROSS THE LOCAL AREA FROM NORTHWEST
TO SOUTHEAST. THIS COMBINATION...WITH PLENTY OF AVAILABLE
INSTABILITY...SHOULD MAKE FOR A MORE ACTIVE AFTERNOON AND
EVENING...AND CONTINUED WITH MENTION OF POTENTIAL SEVERE WEATHER
IN HWO THIS AFTERNOON. WHILE SHEAR IS NOT ALL THAT
IMPRESSIVE...CAPE AND FORCING SHOULD BE SUFFICIENT FOR THE
DEVELOPMENT OF A FEW STORMS WITH MARGINALLY SEVERE HAIL AND
THUNDERSTORM WIND GUSTS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE
PERIOD AND TEMPERATURES.
AN UPPER LEVEL WAVE WILL CONTINUE TO MOVE THROUGH THE AREA THURSDAY
NIGHT. THUNDERSTORMS WILL CONTINUE ACROSS THE AREA DURING THE
EVENING BUT GRADUALLY COME TO AN END FROM NORTHWEST TO SOUTHEAST
DURING THE OVERNIGHT HOURS AND INTO FRIDAY MORNING. MUCAPE REMAINS
AROUND 3000 J/KG DURING THE EVENING BUT DROPS OFF LATER IN THE
NIGHT. ON FRIDAY THE UPPER LEVEL RIDGE IN THE ROCKIES STARTS TO
SLIDE TO THE EAST AND WITH THE RAIN MOVING OUT...TEMPERATURES WILL
WARM SOME.
FRIDAY NIGHT INTO SUNDAY THE UPPER LEVEL RIDGE BUILDS ACROSS THE
AREA AND EXPECT DRY CONDITIONS AND TEMPERATURES WILL CONTINUE TO
WARM A FEW DEGREES.
AN UPPER LEVEL WAVE WILL MOVE OVER THE RIDGE SUNDAY NIGHT AND BRING
A SMALL CHANCE FOR THUNDERSTORMS. THERE SHOULD BE A BRIEF BREAK FROM
THUNDERSTORMS AGAIN ON MONDAY BUT ANOTHER UPPER LEVEL WAVE MOVES
INTO THE AREA MONDAY NIGHT AND TUESDAY. THERE IS ALSO A WEAK COLD
FRONT THAT MOVES THROUGH THE FORECAST AREA MONDAY NIGHT.
THUNDERSTORMS ARE EXPECTED ALONG AND BEHIND THE COLD FRONT. DESPITE
THE COLD FRONT TEMPERATURES SHOULD CONTINUE TO WARM A DEGREE OR TWO
EACH DAY AS THE UPPER RIDGE SETTLES OVER THE PLAINS.
TUESDAY NIGHT AND WEDNESDAY THE MODELS HAVE SOME DIFFERENCES IN THE
MAIN PATTERN. THE GFS HAS AN UPPER RIDGE...WHILE THE ECMWF HAS A
TROUGH MOVING THROUGH. WILL HAVE A SMALL CHANCE FOR THUNDERSTORMS
FOR NOW. THE TEMPERATURE SHOULD REMAIN ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CDT THU AUG 15 2013
REST OF TNGT: REMOVED FOG AND LOW CIGS FROM THE TAF BASED ON
LBF/OAX SOUNDINGS AS WELL AS WIND AND DWPT TRENDS FROM YESTERDAY
AFTN. EXPECT VFR CIGS MAY GO SCT AT TIMES. THERE IS A CLUSTER OF
TSTMS OVER THE NEB PANHANDLE THAT WILL NEED TO BE MONITORED FOR
POSSIBLE INSERTION INTO THE TAF TOWARD DAWN. S WINDS UNDER 10 KTS.
THU: LOW-END VFR CIGS SHOULD INCREASE TO MID-LVL CIGS FROM THE
REMNANTS OF NEARBY TSTM CLUSTER. BY 18Z...CURRENT EXPECTATION IS
FOR SCT VFR CU TO DEVELOP WITH CB POSSIBLE AFTER 21Z. THERE IS A
LOW PROBABILITY FOR 1 INCH HAIL AND G50 KTS IF THE TERMINAL TAKES
A DIRECT HIT FROM AN AFTN OR EVNG TSTM. S WINDS LESS THAN 10 KTS
WILL BACK TO SE.
THU EVNG: TSTM THREAT SHOULD BE OVER BY 03Z. WE ARE SEEING SIGNALS
OF POSSIBLE IFR FOG AFTER 06Z.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
WX CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...SAR
LONG TERM...JCB
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
300 AM PDT THU AUG 15 2013
.SYNOPSIS...MOISTURE IS EXPECTED TO INCREASE OVER THE NEXT COUPLE OF
DAYS BRINGING ISOLATED THUNDERSTORMS TO PORTIONS OF MOHAVE COUNTY
TODAY. THUNDERSTORM COVERAGE IS FORECAST TO EXTEND FURTHER NORTH AND
EAST ON FRIDAY AS MONSOONAL MOISTURE INCREASES OVER THE REGION.
TEMPERATURES WILL INCREASE A COUPLE OF DEGREES TODAY...BUT MAY LOWER
A COUPLE OF DEGREES ON FRIDAY DUE TO THE ADDED CLOUD COVER.
TEMPERATURES ARE FORECAST TO REMAIN AROUND NORMAL FROM SATURDAY INTO
EARLY NEXT WEEK.
&&
.SHORT TERM...HAD A FEW THUNDERSTORMS POP UP EARLY THIS MORNING OVER
FAR SOUTHERN MOHAVE COUNTY. HARD TO DISTINGUISH ANY FEATURES ON
SATELLITE...BUT THE RUC AND NEW NAM WAS SHOWING A WEAK AREA OF
VORTICITY PUSHING NORTHEAST THROUGH THAT GENERAL AREA. IT COULD ALSO
BE ENHANCED BY A WEAK JET STREAK PUSHING THROUGH SOUTHERN
NEVADA/NORTHWEST ARIZONA. IN EITHER CASE THE MODELS INDICATE A
GENERAL DOWNTREND TO THESE STORMS OVER THE NEXT FEW HOURS AS THESE
FEATURES MOVE EAST OF THE AREA. MOISTURE HAS BEEN ON THE GENERAL
INCREASE WITH PW SENSORS IN THE REGION SHOWING READINGS APPROACHING
AN INCH. ALTHOUGH MOISTURE WILL CONTINUE TO INCREASE TODAY THINK
THAT THINGS WILL BE A LITTLE TOO CAPPED TO GENERATE MUCH IN THE WAY
OF ANYTHING MORE THAN AN ISOLATED THUNDERSTORM OR TWO THIS
AFTERNOON...ESPECIALLY OUTSIDE OF FAR EASTERN MOHAVE COUNTY. WE WILL
CERTAINLY SEE AN INCREASE IN CLOUDS OVER THE REMAINDER OF MOHAVE AND
INTO CLARK COUNTY TODAY...BUT REALLY DONT EXPECT TO SEE THOSE
DEVELOP INTO STORMS. BETTER MOISTURE AND INSTABILITY LOOK TO ADVECT
INTO THE REGION FRIDAY AND IT LOOKS LIKE THUNDERSTORM CHANCES WILL
INCREASE. MODELS INDICATE PW VALUES INCREASING TO BETWEEN 1.00-1.25
INCHES OVER MUCH OF THE EASTERN HALF OF THE CWA ALONG WITH LI VALUES
BETWEEN 0/-2 AND A DECENT AMOUNT OF CAPE. HAVE GONE AHEAD AND RAISED
POPS ON FRIDAY INTO THE ISOLATED TO SCATTERED CATEGORY. ALTHOUGH
SOME STORMS ON FRIDAY COULD PRODUCE HEAVY RAIN...IT SEEMS THAT GUSTY
WINDS AND HAIL WILL BE THE PRIMARY CONCERN...ESPECIALLY OVER MOHAVE
COUNTY. TEMPERATURES WILL WARM A COUPLE OF DEGREES TODAY...BUT LOWER
SLIGHTLY ON FRIDAY AS MORE CLOUD COVER SHOULD KEEP READINGS DOWN.
.LONG TERM...SATURDAY THROUGH WEDNESDAY...MODELS DIVERGE AS EARLY AS
SATURDAY ON THEIR HANDLING OF SOUTHERN STREAM ENERGY APPROACHING THE
CENTRAL CALIFORNIA COAST. 00Z GFS/GFS ENSEMBLE MEAN ARE THE SLOWEST
SOLUTIONS KEEPING A CLOSED LOW OFF THE CENTRAL CALIFORNIA COAST
THROUGH MONDAY. ECMWF/GEM ARE SLIGHTLY FURTHER EAST POSITIONING
TROUGH AXIS JUST INLAND INTO CALIFORNIA. OVER THE PAST FEW DAYS THE
ECMWF HAS BEEN TRENDING SLOWER. SO WHAT DOES ALL THAT MEAN FOR
SATURDAY THROUGH MONDAY. FAVORABLE MOISTURE AND INSTABILITY
PARAMETERS WILL CONTINUE TO LIE OVER LINCOLN...NORTHEAST CLARK AND
MOHAVE COUNTIES SATURDAY THROUGH MONDAY. FURTHER WEST...DECREASING
INSTABILITY ASSOCIATED UNDER COLD POOL ALOFT WILL AID IN THE
DEVELOPMENT OF ISOLATED SHOWERS/THUNDERSTORMS FOR THE EASTERN SLOPES
OF THE SOUTHERN SIERRA OF INYO COUNTY.
ON TUESDAY AND WEDNESDAY...GFS/GEM SHOW AN OPEN TROUGH INLAND ACROSS
THE WESTERN GREAT BASIN WHICH WOULD SUGGEST A DRYING TREND. THE
ECMWF IS THE OUTLIER SUGGESTING THE LOW OVER CENTRAL CALIFORNIA
WOULD WEAKEN WITH HIGH PRESSURE RETURNING TO THE AREA. THERE WOULD
BE ENOUGH RESIDUAL MID-LEVEL MOISTURE AROUND TO GENERATE CONVECTION
OVER THE MOUNTAINS WITH THE ECMWF SOLUTION. WITH DIFFERENCES STILL
OCCURRING MADE NO CHANGES TO TUESDAY AND WEDNESDAY AS WE AWAIT
BETTER MODEL AGREEMENT. DID LOWER HIGH TEMPERATURES A DEGREE OR TWO
OVER THE WEEKEND AS 00Z ECMWF NUMBERS NOT AS HIGH AS PREVIOUS RUNS.
IN FACT...THE CURRENT VALUES MAY STILL BE A DEGREE OR TWO TOO
WARM.
&&
.AVIATION...FOR MCCARRAN...SOUTHWEST WINDS THROUGH THIS MORNING
BEFORE TURNING TO THE SOUTHEAST AROUND 8-10 KTS AFTER 19Z. THESE
SOUTHEAST WINDS SHOULD CONTINUE THROUGH SUNSET BEFORE SHIFTING BACK
TO THE SOUTHWEST AROUND 8-10 KTS. FEW-SCT CLOUDS DEVELOPING THIS
AFTERNOON WITH ISOLATED THUNDERSTORMS AFFECTING THE PEACH SPRINGS
AND MORMON MESA CORRIDORS.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED THUNDERSTORMS OVER PORTIONS OF MOHAVE COUNTY
THROUGH TODAY WITH FEW-SCT CLOUDS AROUND 14K FEET ELSEWHERE. WINDS
WILL GENERALLY REMAIN UNDER 12 KTS AND FAVOR A EAST TO SOUTHEAST
DIRECTION FOR MUCH OF TODAY.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
GORELOW/PIERCE
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1257 AM CDT THU AUG 15 2013
.UPDATE...
06Z AVIATION DISCUSSION UPDATED BELOW.
&&
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
PRETTY QUIET ACROSS THE CWA THIS AFTERNOON BUT WILL BE WATCHING
THE WESTERN CWA OVER THE NEXT FEW HOURS FOR THE POTENTIAL FOR A
FEW ISOLD THUNDERSHOWERS AS SHORTWAVE ENERGY APPROACHES FROM THE
MIDWEST. BEST SUPPORT DOES NOT ARRIVE UNTIL LATER THIS
EVENING...BUT DAYTIME HEATING ACROSS THE WESTERN CWA HAS ALLOWED
MLCAPE TO APPROACH 1000 J/KG. SHEAR IS LACKING ONCE AGAIN AS HAS
BEEN THE CASE THE PAST FEW DAYS. CURRENTLY SEEING A CONGESTED CU
FIELD ACROSS NORTH CENTRAL SD WITH RADAR ECHOES JUST BEGINNING TO
INCREASE OVER CORSON COUNTY. HRRR ACTUALLY PICKING UP ON THIS AND
SHOWING A FEW POPCORN TYPE LIGHT SHOWERS OR MAYBE A MODERATE
THUNDERSHOWER THROUGH LATE AFTERNOON. WILL MAINTAIN SLIGHT CHANCE
POPS FOR THE WESTERN CWA THROUGH THE AFTERNOON. MAIN SHORTWAVE
ENERGY APPROACHES THE REGION LATER THIS EVENING...BUT MODELS NOT
TOO IMPRESSED WITH THIS FOR OUR CWA. 12Z NSSL WRF SHOWS A LINE OF
SHOWERS AND STORMS MOVING INTO WESTERN SD LATER THIS EVENING BUT
DIES OUT AS ITS ENTERING THE WESTERN CWA. WILL MAINTAIN SMALL POPS
OVERNIGHT AS WELL...BUT HAVE TRIMMED THINGS DOWN TO DRY FOR THE
EASTERN CWA AS THERE JUST DOESNT SEEM TO BE ANY SUPPORT FOR
PRECIP. THERE REALLY IS NO LOW LEVEL JET TO SPEAK OF OVERNIGHT
EITHER.
WEAK SHORTWAVE ENERGY MOVES SOUTHEAST OVER THE AREA ON THURSDAY
BUT MODELS KEEP TRENDING DRIER AND DRIER FOR THIS...TO THE POINT
NOW WHERE MOST MODELS ARENT EVEN SHOWING ANY PRECIP FOR THE AREA.
HAVE SCALED BACK POPS QUITE A BIT...GOING DRY IN PLACES BUT
KEEPING A SLIGHT CHANCE GOING FOR MOST PLACES. AFTER
THURSDAY...THE WARM UP BEGINS AS UPPER RIDGING BUILDS OVER THE
HIGH PLAINS AND DAKOTAS.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
MAIN CHALLENGE IN THE LONG TERM WILL BE PRECIP CHANCES UNDER THE
DOMINANT UPPER RIDGE.
MODELS ARE NOT IN GOOD AGREEMENT TODAY IN THE EXTENDED. TOSSED OUT
THE GEM AS IT IS THE ONLY MODEL SHOWING A DEVELOPING TROPICAL
SYSTEM IN THE GULF THIS WEEKEND. THIS MAY CONTAMINATE QPF AND
PRESSURE FIELDS ALL THE WAY NORTH INTO THE DAKOTAS. GFS AND ECMWF
ARE BOTH FLIP FLOPPING WITH MOISTURE FIELDS THOUGH SFC PRESSURE
PROGS ARE SIMILAR. BOTH MODELS SHOW TWO TROFS MOVING ACROSS THE
DAKOTAS...ONE SUNDAY NIGHT/MONDAY AND ANOTHER TUESDAY
NIGHT/WEDNESDAY. HOWEVER THE GFS IS WET FOR THE FIRST AND DRY FOR
THE SECOND WHILE THE ECMWF IS OPPOSITE. STUCK WITH ALLBLEND POPS
SUNDAY NIGHT/MONDAY AS 30S/40S SEEM REASONABLE AT THIS POINT. WENT
DRIER THAN ALLBLEND FOR THE END OF THE PERIOD BASED ON INTER
OFFICE COLLABORATION.
TEMPERATURES SHOULD BE ON THE RISE THROUGH THE PERIOD WITH HIGHS
IN THE UPPER 80S TO LOWER 90S EXPECTED.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
FAIRLY TRANQUIL VFR CONDITIONS WILL CONTINUE TO PREVAIL ACROSS THE
LOCAL TERMINALS AS THE REGION REMAINS BETWEEN HIGH PRESSURE TO THE
EAST AND LOW PRESSURE TO THE WEST. LIGHT SOUTH TO SOUTHEAST WINDS
CAN BE EXPECTED TONIGHT INTO THURSDAY. AN ISOLATED SHOWER OR
THUNDERSTORM IS POSSIBLE OVER/NEAR THE WESTERN TAF SITES LATE
TONIGHT. A TEMPORARY MVFR/IFR FOG/STRATUS CONDITION IS POSSIBLE AT
ANY OF THE FOUR TERMINALS BY LATE TONIGHT INTO THURSDAY
MORNING...AS LOW LEVEL MOISTURE STEADILY INCREASES ACROSS THE
REGION. BY LATE THURSDAY MORNING...VFR CONDITIONS SHOULD BE
RETURNING OR ONGOING AT ALL TERMINALS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 PM CDT WED AUG 14 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 333 PM CDT WED AUG 14 2013
AT 3 PM...THE SATELLITE LOOP SHOWED A BROKEN DECK OF 7 TO 8K FOOT
CLOUDS ACROSS THE FORECAST AREA. THE RAP SEEMS TO HAVE THE BEST
HANDLE ON THESE CLOUDS AND THEY SHOW THAT THESE CLOUDS WILL
GRADUALLY DISSIPATE THIS EVENING.
FOR LATE TONIGHT AND THURSDAY MORNING...THE BUFKIT SOUNDINGS SHOW
THAT THERE WILL BE A DEEP LAYER /UP TO 775 MB/ OF LIGHT WINDS
ACROSS THE AREA. WHILE THIS WOULD BE FAVORABLE FOR THE DEVELOPMENT
OF VALLEY FOG. THE NAM/WRF...GFS...AND RAP CONTINUE TO SHOW THAT
THE TEMPERATURE/DEW POINT SPREAD WILL REMAIN AT OR ABOVE 1C. IN
ADDITION...THE GFS AND NAM/WRF SUGGEST THAT THERE COULD BE STILL
SOME CLOUDS AROUND THE REGION. AS A RESULT...WENT WITH PATCHY
VALLEY FOG FOR THE MISSISSIPPI RIVER AND ITS TRIBUTARIES...AND
AREAS OF FOG IN THE WISCONSIN RIVER VALLEY.
ON THURSDAY...THE MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH
WILL MOVE SOUTHEAST ACROSS SOUTHERN AND WESTERN IOWA. WEAK 925 AND
850 MB MOISTURE TRANSPORT NORTHEAST OF THIS SYSTEM WILL AID IN THE
DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND SOUTHWEST
WISCONSIN. WITH ML CAPES LESS THAN 400 J/KG AND VERY WEAK 0-3 KM
AND 0-6 KM...NONE OF THESE THUNDERSTORMS ARE EXPECTED TO BECOME
SEVERE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 333 PM CDT WED AUG 14 2013
ON FRIDAY...THE 925 MB AND 850 MB WEAK MOISTURE TRANSPORT AND 700
TO 600 MB FRONTOGENESIS REMAINS SOUTHWEST OF THE FORECAST AREA.
IN ADDITION...THERE IS VERY LITTLE SURFACE MOISTURE CONVERGENCE
ACROSS THE AREA. WITH THE MESO MODELS IN AGREEMENT WITH THE GEM
AND ECMWF THAT THE AREA WILL REMAIN DRY...REMOVED THE
PRECIPITATION CHANCES FOR THIS TIME PERIOD.
ON BOTH THURSDAY AND FRIDAY NIGHTS...BOTH THE GFS AND NAM/WRF
SOUNDINGS SHOW A DEEP LAYER /UP TO AT LEAST 800 MB/ OF LIGHT
WINDS. THIS WOULD BE VERY FAVORABLE FOR THE DEVELOPMENT OF VALLEY
FOG. HOWEVER THEY ALSO HINT THAT THERE MAY BE SOME CLOUDS AROUND
THE REGION. ANOTHER FACTOR THAT MAY BE A LIMITING FACTOR IS THE
AMOUNT OF MOISTURE IN THE BOUNDARY LAYER. THE NAM/WRF HAS MUCH
MORE MOISTURE THAN THE GFS. DUE TO THIS UNCERTAINTY...JUST
INTRODUCED PATCHY TO AREAS OF VALLEY FOG ON BOTH NIGHTS.
FROM MONDAY THROUGH WEDNESDAY...THE MODELS ARE CONTINUING TO
STRUGGLE WITH THE 500 MB UPPER AIR PATTERN. THE GFS AND GEM ARE
SHOWING THAT THE UPPER LEVEL RIDGE REMAINS LONGER TO THE WEST THAN
THE ECMWF. AS A RESULT...THE GFS AND GEM ARE FASTER AT MOVING THE
COLD FRONT SOUTHEAST INTO THE FORECAST AREA. MEANWHILE THE ECMWF
HAS THE FRONT REMAINING WELL NORTHWEST OF THE FORECAST AREA. SINCE
THE MODELS HAVE BEEN TRENDING SLOWER DURING THIS TIME PERIOD...THE
CONSENSUS OF OUR OFFICE AND THE SURROUNDING WFOS TO KEEP MOST OF
THE FORECAST AREA DRY DURING THIS TIME FRAME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1130 PM CDT WED AUG 14 2013
THE VALLEY FOG FORECAST FOR THIS MORNING AT LSE REMAINS
PROBLEMATIC. THE WIND FIELD IS VERY FAVORABLE FOR VALLEY FOG...BUT
SCT-OVC HIGH BASED CUMULUS PERSISTS WHICH HAS KEPT THE
TEMPERATURE/DEWPOINT SPREAD JUST SLIGHTLY HIGHER THAN IDEAL. WITH
VARIOUS MODELS SUCH AS THE RAP...GFS AND NAM CONTINUING TO
INDICATE THE CLOUDS GOING NOWHERE...THINK ANY VALLEY FOG WILL
OCCUR MORE AWAY FROM THE AIRPORT IN THE NARROWER VALLEYS...AND
POSSIBLY THE NARROWER SECTION OF THE MISSISSIPPI SOUTH OF LA
CROSSE. HAVE PLAYED THE FOG WITH A VCFG AND SCT003...BUT SHOULD
THE CLOUDS CLEAR EARLY THIS MORNING...MORE FOG AND LOWER
VISIBILITIES WILL BE REQUIRED. OTHERWISE...THESE HIGH BASED
CUMULUS CLOUDS OF A SCT-BKN VARIETY SHOULD PERSIST THROUGH THE TAF
PERIOD UNDER A LIGHT SURFACE WIND REGIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
950 AM CDT THU AUG 15 2013
.DISCUSSION...
949 AM CDT
VERY FEW CHANGES MADE TO THE GOING FORECAST THIS MORNING. A COUPLE
SHORT WAVES ARE PROGRESSING SOUTHEAST ACROSS NEBRASKA AND IOWA
THIS MORNING...WITH THE FURTHER EAST ONE GRADUALLY SHEARING OUT
FROM CENTRAL IA INTO FAR NW IL. THIS HAS AND WILL CONTINUE TO BE
RESPONSIBLE FOR THE HIGH CLOUDS WHICH THE RAP MODEL HAS A GOOD
HANDLE ON RIGHT NOW. HAVE GUIDED SKY GRIDS CLOSE TO ITS 500-600MB
RH PREDICTION AND THAT WAS IN LINE WITH EARLIER FORECAST
REASONING...KEEPING SOUTHERN AREAS NEAR YESTERDAYS HIGHS AND
SLIGHTLY WARMER IN THE NORTH. HAVE JUST ADJUSTED THE HOURLY
TEMPERATURE TRENDS SOME AS FAR NORTHERN AREAS MAY BE A LITTLE SLOW
TO CLIMB THIS MORNING GIVEN CURRENT CLOUD TRENDS. SOUTHWEST
BOUNDARY LAYER WINDS PER DOPPLER VAD AND SURFACE OBSERVATIONS HAVE
BEEN AROUND 10 KT IN NORTHEAST IL WHICH SHOULD BE ENOUGH TO
OFFSET THE LAKE BREEZE INTO EARLY AFTERNOON. THIS WIND SHIFT SHOULD
STILL DEVELOP AND PROGRESS INLAND FOR SOME COOLING. DID ADJUST UP
LAKESHORE HIGHS UPWARD DUE TO THE LATER EXPECTED DEVELOPMENT...WITH
DOWNTOWN CHICAGO LIKELY PEAKING SOMEWHERE IN THE 72 TO 74 RANGE.
MTF
&&
.PREV DISCUSSION...
247 AM CDT
NOT MUCH CHANGE IN OVERALL FORECAST THINKING FROM PREVIOUS NIGHTS AS
HIGH PRESSURE CONTINUES TO PROVIDE QUIET WEATHER WITH A GRADUAL
WARMING TREND INTO EARLY NEXT WEEK AS IT DEPARTS. FOCUS WILL BE ON
FORECAST SUBTLETIES INCLUDING CLOUD COVER AND SOME MINIMAL PRECIP
CHANCES NEXT WEEK. EARLY MORNING WATER VAPOR IMAGERY SHOWS THE BIG
CLOSED UPPER LOW THAT ORIGINALLY BROUGHT THE UNSEASONABLY COOL AIR
TO THE REGION STILL SPINNING OVER JAMES BAY AND NORTHWESTERN
QUEBEC...WITH A SECONDARY LOW SPINNING OVER THE GULF OF ST.
LAWRENCE. UPPER RIDGING REMAINS STRETCHED FROM THE FOUR CORNERS INTO
ALBERTA/SASKATCHEWAN WITH A BIG UPPER LOW OFF THE BRITISH COLUMBIA
COAST MOVING NORTHWARD UP THE WESTERN FLANK OF THE RIDGE.
LOCALLY...THE AREA REMAINS UNDER A NORTHWESTERLY UPPER FLOW IN WHICH
SEVERAL SHORTWAVES ARE MOVING ACROSS THE PLAINS. AT THE
SURFACE...HIGH PRESSURE IS CENTERED OVER NORTHERN INDIANA AND
EXTENDS WEST INTO IOWA AND NORTH INTO THE CANADIAN PRAIRIES.
TODAY AND TONIGHT...THE SHORTWAVES NOTED ABOVE THAT ARE
TRAVERSING THE NORTHWEST UPPER FLOW OVER THE MID SECTION OF THE
COUNTRY WILL PRIMARILY STAY ON A TRAJECTORY TO TAKE THE MOST FOCUSED
FORCING SOUTHWEST OF THE CWA THROUGH FRIDAY. WATER VAPOR SHOWS A
DECENT INFLUX OF MID/HIGH LEVEL MOISTURE SPREADING EASTWARD ACROSS
THE MID AND UPPER MISSISSIPPI RIVER VALLEY WITH IR IMAGERY SHOWING
A LARGE AREA OF MID AND HIGH CLOUD DRIFTING ACROSS EASTERN
NEBRASKA/IOWA/MISSOURI. THE THICKER PORTION OF THIS BAND WILL LIKELY
MOVE ACROSS THE SOUTHERN CWA THROUGH THE MORNING WHILE THE HIGHER
AND THINNER NORTHERN EXTENT SPREADS ACROSS THE REMAINDER OF THE
AREA. BY AFTERNOON...FAR NORTHERN COUNTIES SHOULD SEE THE LEAST
COVERAGE WHILE SOUTHERN AREAS SEE AT LEAST SOME COVERAGE THROUGH
LATE DAY. WITH HIGH PRESSURE STILL CLOSE BY WINDS WILL BE LIGHT AND
MIXING WILL ONCE AGAIN BE WEAK...ESPECIALLY THANKS TO THE CLOUD
COVER. GIVEN THESE LIMITING FACTORS FOR MAX WARMING...WILL ADJUST
FORECAST HIGHS TO BE SIMILAR TO THOSE OF WEDNESDAY ACROSS THE
SOUTHERN CWA BUT MAINTAIN THE SLIGHT WARM UP OVER NORTHERN AREAS. A
LAKE BREEZE IS ONCE AGAIN EXPECTED THOUGH HAVE SOME QUESTION OF HOW
QUICKLY IT WILL DO SO GIVEN THE CLOUD COVER. LOW LEVEL FLOW IS SO
WEAK THOUGH THAT THERE DOES NOT LOOK TO BE A PROBLEM DEVELOPING ONE
IT MAY JUST TAKE LONGER TO MOVE INLAND. THIS MAY ALLOW LAKEFRONT
AREAS TO WARM UP A FEW DEGREES OVER WEDNESDAY AND REACH THE 70
DEGREE MARK. OTHERWISE...DO EXPECT SOME DIURNAL STRATOCU TO DEVELOP
UNDER THE MID AND HIGH CLOUDS THOUGH IT MAY BE A BIT MORE SCATTERED
IN COVERAGE THAN RECENT DAYS AND MAY TAKE A LITTLE LONGER TO
DEVELOP. SOME CIRRUS MAY LINGER SOUTH TONIGHT BUT OTHERWISE EXPECT
MOSTLY CLEAR SKIES AND LIGHT WINDS SO OVERNIGHT LOWS WILL ONCE AGAIN
BE IN THE 50S AWAY FROM THE URBAN HEAT ISLAND. A FEW OF THE
TRADITIONALLY COLDER SPOTS MAY FALL INTO THE UPPER 40S.
FRIDAY AND SATURDAY...AN UPPER TROUGH AXIS WILL BE AMPLIFYING FROM
LAKE MICHIGAN SOUTHWESTWARD THROUGH FRIDAY BUT THE BASE OF THE
TROUGH AND ASSOCIATED FORCING WILL REMAIN WELL TO THE SOUTH AND WEST
SO EXPECT A CONTINUATION OF DRY CONDITIONS. THE AIRMASS WILL MODIFY
SLIGHTLY WITH H85 TEMPS WARMING A FEW DEGREES WHICH WILL ALLOW HIGHS
TO WARM INTO THE MID AND UPPER 70S. EASTERLY FLOW WILL BE IN PLACE
SO LAKEFRONT AREAS WILL LIKELY BE HELD INTO THE LOWER 70S. EXPECT
SIMILAR CONDITIONS SATURDAY.
SUNDAY THROUGH WEDNESDAY...GUIDANCE CONTINUES TO STRUGGLE WITH THE
EVOLUTION OF THE NEWLY DEVELOPED UPPER TROUGH THAT WILL FOCUS OVER
THE LOWER MISSISSIPPI AND OHIO RIVER VALLEYS. THE IDEA OF THIS
TROUGH STAYING TO THE SOUTH THEN GRADUALLY WORKING ITS WAY
NORTHEASTWARD...KEEPING ASSOCIATED FORCING...MOISTURE AND RESULTANT
PRECIP CHANCES MAINLY TO THE SOUTH AND EAST OF THE AREA...HAS BEEN
CONSISTENT. WOULD NOT BE SURPRISED TO SEE SOME CONTINUED VARIATION IN
THE EVOLUTION OF THE TROUGH BUT WILL STICK WITH LITTLE IF ANY POP
MENTION FROM SUNDAY INTO EARLY NEXT WEEK. THE GRADUAL WARMING TREND
CONTINUES WITH HIGHS IN THE 80S EXPECTED BY SUNDAY AWAY FROM THE
LAKE. CONFIDENCE LOWERS BY THE MIDDLE OF NEXT WEEK BUT IT DOES
APPEAR THAT THE TROUGH WILL DEPART ALLOWING A PERIOD OF UPPER
RIDGING TO BUILD IN SUGGESTING A FURTHER WARMING OF TEMPS. THIS
WOULD ALSO KEEP PRECIP CHANCES TO THE NORTH...THOUGH IT WOULD NOT BE
OUT OF THE QUESTION FOR SOMETHING TO DEVELOP AS THE RIDGE
APPROACHES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* WEAK LAKE BREEZE TO DEVELOP EARLY AFTERNOON AND MOVE INLAND TO
REACH ORD AND MDW MID TO LATE AFTERNOON FLIPPING LIGHT WINDS TO
OUT OF THE E-SE.
TRS
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE OVER THE REGION WILL CONTINUE THE QUIET VFR
CONDITIONS. THE WEAK GRADIENT AND VERY LIGHT WINDS ALOFT SHOULD
ALLOW FOR ANOTHER LAKE BREEZE TO DEVELOP AND PUSH INLAND DURING
THE AFTERNOON. FAIRLY DENSE CIRRUS SHIELD OVERHEAD COULD SUPPRESS
WARMING A BIT AND INITIALLY SLOW THE PROGRESSION OF THE LAKE
BREEZE...SO THE EASTERLY WIND SHIFT AT ORD AND MDW COULD BE A BIT
LATER IN THE AFTERNOON THAN ON WEDNESDAY AND THE BOUNDARY MAY NOT
PUSH THROUGH DPA. ONCE THE SHIFT TO EAST WINDS OCCURS AT ORD AND
MDW...SPEEDS SHOULD AGAIN BE MAINLY UNDER 10 KT...EXCEPT POSSIBLY
SHORTLY AFTER THE LAKE BREEZE PASSAGE. SCT TO BKN VFR CU WILL
DEVELOP UNDER THE CIRRUS SHIELD BEFORE CLEARING THIS EVENING.
LIGHT AND VRB TO CALM WINDS AGAIN TONIGHT WILL BECOME LIGHT
NORTHEAST MID TOMORROW MORNING BEFORE FLOPPING OVER TO EAST BY
EARLY AFTERNOON.
RC
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM ON WEAK LAKE BREEZE REACHING ORD AND MDW MID TO LATE
AFTERNOON.
* HIGH ON PREVAILING SPEED REMAINS BELOW 10 KT THROUGH THE DAY.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH MONDAY...VFR.
TUESDAY AND WEDNESDAY...SLIGHT CHANCE TSRA TUES NIGHT AND
WEDNESDAY.
RC
&&
.MARINE...
316 AM CDT
EXPANSIVE HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER
PATTERN ACROSS THE LAKE THROUGH THE WEEKEND. MODESTLY STRONG
SOUTHWEST WINDS OVER THE NORTH HALF EARLY THIS MORNING WILL SHIFT
WEST AND THEN RETURN TO SOUTHWEST THIS AFTERNOON WHILE
DIMINISHING. THE SOUTH HALF COULD SEE A BRIEF PERIOD THIS MORNING
WHEN WINDS SHIFT WEST AND GUST TO 20 KT BUT OTHERWISE SOUTHWEST
WINDS 15 KT OR LESS WILL DIMINISH FURTHER TONIGHT.
THEREAFTER...THE NORTH HALF WILL SEE AN EXTENDED PERIOD OF
SOUTHWEST WINDS OF 15 KT OR LESS AND THE SOUTH 10 KT OR LESS WITH
PERIODS OF VARIABLE WINDS UNTIL SUNDAY WHEN HIGH PRESSURE FINALLY
SHIFTS EAST. AS LOW PRESSURE TAKES SHAPE ACROSS THE CANADIAN
PRAIRIES AND PUSHES EAST SUNDAY NIGHT INTO MONDAY...THE TIGHTER
PRESSURE GRADIENT...ESPECIALLY OVER THE NORTH HALF...WILL RESULT
IN INCREASED SOUTHWEST WINDS. A WARM AIR MASS OVER THE LAKE BY
THAT TIME WILL LIKELY LIMIT MIXING AND GUSTS...BUT WINDS TO 25 KT
ARE POSSIBLE ACROSS THE FAR NORTH ON MONDAY.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS HASTINGS NE
653 AM CDT THU AUG 15 2013
.UPDATE...
ISSUED AT 652 AM CDT THU AUG 15 2013
NO SUBSTANTIAL CHANGES MADE TO THE FCST...BUT DID MAKE SOME
ADJUSTMENTS TO INCREASE SKY AND TIMING/LOCATION ADJUSTMENTS TO
POPS. ALSO DECREASED TEMPS THRU EARLY AFTN TU SUPPRESS THE DIURNAL
RISE...ACCOUNTING FOR RAIN AND CLOUDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 431 AM CDT THU AUG 15 2013
ALOFT: NW FLOW WILL CONT OVER THE PLAINS THRU TNGT...WITHIN AN
AMPLIFIED ROCKIES RIDGE/ERN USA TROF LGWV PATTERN. WV IMAGERY SHOWED
A WELL-DEFINED SHRTWV TROF OVER ERN MT/NERN WY. THIS TROF WILL CONT
MOVING SE TODAY AND WILL BE LOCATED ALONG THE KS/OK BORDER BY
DAYBREAK FRI.
SFC: 1024 MB HIGH PRES WAS OVER THE OH VALLEY EARLY THIS MRNG. THIS
HIGH WILL ESSENTIALLY EXPAND E INTO THE MID-ATLANTIC...REMAINING
FAIRLY STATIONARY. THE MAIN POLAR FRONT WILL ALSO REMAIN STALLED
WELL S OF THE FCST AREA...OVER TX AND THE GULF COAST STATES. AN E-W
ORIENTED SFC TROF WAS NOTED OVER NEB /ROUGHLY ALONG I-80/ AND ITS
WRN END WAS ATTACHED TO A WEAK LEE-SIDE LOW OVER THE PANHANDLE. THIS
TROF IS FCST TO REMAIN IN PLACE /UNLESS IT BECOMES MODULATED OR
PARTIALLY DESTROYED BY ON-GOING CONVECTION THIS MRNG/. MEANWHILE...
THE LEE-SIDE LOW WILL STRENGTHEN AND SLIDE DOWN THE HIGH PLAINS TO
BE NEAR PUB BY SUNSET.
FCST FOR TODAY IS ESSENTIALLY VARIABLE CLOUDS WITH APPARENTLY A
COUPLE DIFFERENT OPPORTUNITIES FOR TSTMS. CONVECTIVE EVOLUTION
REMAINS COMPLEX AND UNCERTAIN...ESPECIALLY THIS AFTN/EVNG DUE TO THE
ON-GOING CLUSTER OF TSTMS AND ITS INFLUENCE ON FUTURE DEVELOPMENTS.
EARLY THIS MRNG: FOR THE 3RD MRNG IN A ROW WE HAVE A SMALL MCS
APPROACHING AND EXPECT IT TO AFFECT AREAS W AND S OF THE TRI-CITIES
BETWEEN 5-9 AM. THIS WEEK HAS BEEN EXCELLENT FOR MUCH-NEEDED
RAINFALL.
THE 05Z HI-RES RAP AND 00Z WRF FROM THE SD SCHOOL OF MINES AND TECH
LOOK EXCELLENT COMPARED TO REALITY AND HOW THIS MRNG WILL EVOLVE.
THE SMALL MCS WILL CONT INTO THE FCST AREA...PROBABLY WEAKENING WITH
TIME. A FEW SHWRS/POSSIBLE THUNDER? WILL ALSO CONT TO DEVELOP WITHIN
THE LLJ INDUCED WAA/ISENTROPIC ASCENT AHEAD OF THE MCS.
WHAT HAPPENS AFTER THIS MCS DEPARTS REMAINS UP FOR GRABS. THE
REMNANT MCV WILL BE SE OF OUR KS COUNTIES THIS AFTN AND WILL NOT BE
A FACTOR. THE TRAILING OUTFLOW /AND ANY POSSIBLE DIFFERENTIAL
HEATING BOUNDARIES/ WILL NEED TO BE WATCHED FOR CONVECTIVE
INITIATION THIS AFTN...AS WELL AS WHATEVER IS LEFT OF THE E-W
ORIENTED SFC TROF. THE HI-RES RAP AND THE SYNOPTIC-SCALE MODELS FCST
TSTMS OVER THE PANHANDLE THIS MRNG /POSSIBLY THE SMALL TSTM
CLUSTERS CURRENTLY ON-GOING OVER ERN WY/NWRN SD?/ AND THEN INCREASE
IN COVERAGE THIS AFTN AS THEY HEAD SE INTO THE FCST AREA.
WHILE PWAT/S ON 00Z SOUNDINGS ARE ONLY NEAR NORMAL...THE FCST AREA
LIES IN A RIBBON OF DECENT LOW-LVL MSTR /DWPTS LOW-MID 60S/. THE NAM
HIGH TEMPS WERE TOO WARM GIVEN EXPECTED RAINFALL AND CLOUD COVER
TODAY. SO USED THE 03Z SREF MEAN MLCAPE WHICH SUGGESTS 1500-2500
J/KG WITH THE GREATEST VALUES S AND W OF THE TRI-CITIES. THAT COULD
BE TOO HIGH GIVEN THAT A PORTION OF THE INSOLATION THAT OCCURS THIS
AFTN WILL GO TO EVAPORATING RAINFALL...NOT TO MENTION LEFTOVER
CLOUDINESS WHICH WILL RETARD DIURNAL HEATING.
OVERALL TROPOSPHERIC WINDS WILL BE WEAK...BUT DIRECTIONAL SHEAR
/WITH SFC AND MID-LVL WINDS 180 APART/ WILL CONTRIBUTE TO 0-6 KM
SHEAR OF 30-40 KTS /HIGHEST OVER N-CNTRL KS/.
INDIVIDUAL CELL MOVEMENT WILL BE SE AT 15-20 KTS. ANY MULTICELL
CLUSTERS THAT FORM COULD MOVE UP TO 40 KTS THREATENING SOME WIND
DAMAGE. IF A SUPERCELL OR TWO FORMS...MOVEMENT WOULD BE SSW AROUND
20 KTS. HODOGRAPHS WILL BE NEARLY A STRAIGHT-LINE SUGGESTING
SUPERCELL SPLITS A POSSIBILITY.
MAIN THREATS: HAIL TO 1.75" AND STRAIGHT-LINE WINDS TO 60 MPH. AN
ISOLATED TORNADO CAN/T BE COMPLETELY RULED OUT W OF A LINE FROM
LEXINGTON NEB-HOLDREGE-OSBORNE KS...EITHER SUPERCELLULAR WITH 0-1
KM SRH OF 80-100 M2/S2 OR A NON-SUPERCELL TOR ASSOCIATED WITH ANY
BOUNDARIES.
TNGT: SVR TSTMS WILL PROBABLY BE ON-GOING DURING THE EVNG HRS...BUT
SHOULD BE S-SE OF THE FCST AREA BY MIDNGT. WINDS PROBABLY TURN
CALM /OR NEARLY CALM/ AFTER 2 AM. THIS THREATENS SOME FOG WHERE
SKIES CLEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 431 AM CDT THU AUG 15 2013
GUIDANCE SUGGESTS UPPER LEVEL RIDGING WILL PERSIST OVER THE WESTERN
CONUS THROUGH SUNDAY OR MONDAY...BEFORE MOVING EAST INTO PORTIONS OF
THE CENTRAL CONUS BY MID NEXT WEEK. AS A RESULT...NORTH TO
NORTHWESTERLY MID TO UPPER LEVEL FLOW IS EXPECTED OVER THE CENTRAL
PLAINS THROUGH MUCH OF THE LONG TERM FORECAST PERIOD...WITH THIS
FLOW SUBSTANTIALLY DECREASING IN INTENSITY AS THE UPPER LEVEL RIDGE
AXIS MOVES NEAR THE REGION BY EARLY TO MID NEXT WEEK. GIVEN THE
ANTICIPATED LACK IN KINEMATIC FORCING DURING THE EXTENDED FORECAST
PERIOD...AS SUGGESTED BY GUIDANCE...CHANCES FOR PRECIPITATION APPEAR
AS THOUGH THEY WILL REMAIN LOW. THERE SEEMS TO BE PRETTY GOOD
AGREEMENT BETWEEN THE NAM...EC...AND SREF-MEAN OF LINGERING
OVERNIGHT CONVECTION PERHAPS IMPACTING SOUTHERN AND EASTERN PORTIONS
OF OUR CWA FOR A TIME FRIDAY MORNING AND GIVEN THE ~20% POPS
INHERITED FROM THE PREVIOUS FORECAST...OPTED TO KEEP THE
SLIGHT-CHANCE POPS GOING FOR OUR SOUTH AND EAST 12-18Z FRIDAY.
BEYOND 18Z FRIDAY...THE ONLY CHANCE AT OBSERVING MEASURABLE
PRECIPITATION ACROSS THE AREA APPEARS AS THOUGH IT WILL REMAIN
RELEGATED TO THE LATTER PART OF THE LONG TERM FORECAST PERIOD AS THE
AXIS OF A 25-35KT 850MB JET STREAK SETS UP OVER THE AREA. LOW LEVEL
THERMAL ADVECTION ALONG THIS JET STREAK AXIS COULD PROMOTE ISOLATED
TO SCATTERED PRECIPITATION ACROSS THE AREA...A SOLUTION SUPPORTED BY
QPF FIELDS FROM THE OPERATIONAL GFS AND EC...ALTHOUGH IT IS WORTH
MENTIONING THAT THESE MODELS DO NOT AGREE ON WHICH DAYS OR WHICH
LOCATIONS ARE BETTER FAVORED FOR OBSERVING PRECIPITATION. ALLBLEND
RESPONDED BY PROVIDING ~20% POPS TO MUCH OF THE CWA MONDAY NIGHT
THROUGH WEDNESDAY AND GIVEN THE AFOREMENTIONED GUIDANCE...FELT THESE
POPS WERE JUSTIFIED AND THUS WERE LEFT UNCHANGED FOR THE MOST PART.
LITTLE CHANGE IN THE LOW LEVEL AIRMASS SHOULD PRESENT SIMILAR
TEMPERATURES ACROSS OUR AREA FRIDAY AND SATURDAY. PERSISTENT
SOUTHERLY LOW LEVEL FLOW AND RESULTANT THERMAL ADVECTION HOWEVER
SHOULD THEN ALLOW FOR A WARMING TREND DURING THE EARLY TO MID PART
OF NEXT WEEK. AS A RESULT...AFTERNOON HIGHS IN THE UPPER 70S TO LOW
80S ARE CURRENTLY FORECAST FRIDAY AND SATURDAY...WITH HIGHS CLIMBING
INTO THE MID TO UPPER 80S AND EVENTUALLY THE LOWER 90S TO FINISH OUT
THE LONG TERM FORECAST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 652 AM CDT THU AUG 15 2013
TODAY: VFR THOUGH WITH POCKETS OF BRIEF IFR VSBY AND MVFR CIGS IN
SHWRS/TSTMS THRU 14Z-15Z. WHILE VSBY WILL RETURN TO VFR...THERE
COULD BE A PERIOD OF MVFR CIGS AFTER THIS SHWR/TSTM ACTIVITY
DEPARTS. THEN A BREAK BEFORE SCT SHWRS/TSTMS REFORM AFTER 20Z.
EXPECT POCKETS OF MVFR OR IFR VSBYS. THERE IS A LOW PROBABILITY OF
1 INCH HAIL AND G50 KTS IF THE TERMINAL TAKES A DIRECT HIT. LIGHT
S WINDS WILL EVENTUALLY BACK TO SE.
TNGT: TSTM THREAT SHOULD BE OVER BY 03Z. THEN CLEARING WITH
POTENTIAL FOR VFR TO DETERIORATE TO IFR FOG AFTER 08Z. WHILE NOT
INDICATED IN THE TAF...THERE IS POTENTIAL FOR 1/4SM FG VV001.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: LOW IN ANY TSTM AND LATE FOG
WIND CONFIDENCE: HIGH WX EXCEPT NEAR ANY TSTMS
WX CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
500 AM PDT THU AUG 15 2013
.SYNOPSIS...MOISTURE IS EXPECTED TO INCREASE OVER THE NEXT COUPLE OF
DAYS BRINGING ISOLATED THUNDERSTORMS TO PORTIONS OF MOHAVE COUNTY
TODAY. THUNDERSTORM COVERAGE IS FORECAST TO EXTEND FURTHER NORTH AND
EAST ON FRIDAY AS MONSOONAL MOISTURE INCREASES OVER THE REGION.
TEMPERATURES WILL INCREASE A COUPLE OF DEGREES TODAY...BUT MAY LOWER
A COUPLE OF DEGREES ON FRIDAY DUE TO THE ADDED CLOUD COVER.
TEMPERATURES ARE FORECAST TO REMAIN AROUND NORMAL FROM SATURDAY INTO
EARLY NEXT WEEK.
&&
.UPDATE...SATELLITE SHOWS MID CLOUDS DEVELOPING AS FAR NORTH AS THE
LAS VEGAS VALLEY. TIME HEIGHT/FORECAST SOUNDING FOR LAS VEGAS
INDICATE MOISTURE IN THE H7-H5 LAYER PERSISTING THROUGHOUT THE DAY.
SO MADE SOME CHANGES TO SKY GRIDS. ALSO...INCREASED POPS ACROSS
CENTRAL AND SOUTHERN MOHAVE COUNTY THROUGH 18Z AS RADAR SHOWS
ISOLATED LIGHT RAIN SHOWERS CONTINUE TO DEVELOP. PIERCE
&&
.PREV DISCUSSION...
300 AM PDT THU AUG 15 2013
.SHORT TERM...HAD A FEW THUNDERSTORMS POP UP EARLY THIS MORNING OVER
FAR SOUTHERN MOHAVE COUNTY. HARD TO DISTINGUISH ANY FEATURES ON
SATELLITE...BUT THE RUC AND NEW NAM WAS SHOWING A WEAK AREA OF
VORTICITY PUSHING NORTHEAST THROUGH THAT GENERAL AREA. IT COULD ALSO
BE ENHANCED BY A WEAK JET STREAK PUSHING THROUGH SOUTHERN
NEVADA/NORTHWEST ARIZONA. IN EITHER CASE THE MODELS INDICATE A
GENERAL DOWNTREND TO THESE STORMS OVER THE NEXT FEW HOURS AS THESE
FEATURES MOVE EAST OF THE AREA. MOISTURE HAS BEEN ON THE GENERAL
INCREASE WITH PW SENSORS IN THE REGION SHOWING READINGS APPROACHING
AN INCH. ALTHOUGH MOISTURE WILL CONTINUE TO INCREASE TODAY THINK
THAT THINGS WILL BE A LITTLE TOO CAPPED TO GENERATE MUCH IN THE WAY
OF ANYTHING MORE THAN AN ISOLATED THUNDERSTORM OR TWO THIS
AFTERNOON...ESPECIALLY OUTSIDE OF FAR EASTERN MOHAVE COUNTY. WE WILL
CERTAINLY SEE AN INCREASE IN CLOUDS OVER THE REMAINDER OF MOHAVE AND
INTO CLARK COUNTY TODAY...BUT REALLY DONT EXPECT TO SEE THOSE
DEVELOP INTO STORMS. BETTER MOISTURE AND INSTABILITY LOOK TO ADVECT
INTO THE REGION FRIDAY AND IT LOOKS LIKE THUNDERSTORM CHANCES WILL
INCREASE. MODELS INDICATE PW VALUES INCREASING TO BETWEEN 1.00-1.25
INCHES OVER MUCH OF THE EASTERN HALF OF THE CWA ALONG WITH LI VALUES
BETWEEN 0/-2 AND A DECENT AMOUNT OF CAPE. HAVE GONE AHEAD AND RAISED
POPS ON FRIDAY INTO THE ISOLATED TO SCATTERED CATEGORY. ALTHOUGH
SOME STORMS ON FRIDAY COULD PRODUCE HEAVY RAIN...IT SEEMS THAT GUSTY
WINDS AND HAIL WILL BE THE PRIMARY CONCERN...ESPECIALLY OVER MOHAVE
COUNTY. TEMPERATURES WILL WARM A COUPLE OF DEGREES TODAY...BUT LOWER
SLIGHTLY ON FRIDAY AS MORE CLOUD COVER SHOULD KEEP READINGS DOWN.
.LONG TERM...SATURDAY THROUGH WEDNESDAY...MODELS DIVERGE AS EARLY AS
SATURDAY ON THEIR HANDLING OF SOUTHERN STREAM ENERGY APPROACHING THE
CENTRAL CALIFORNIA COAST. 00Z GFS/GFS ENSEMBLE MEAN ARE THE SLOWEST
SOLUTIONS KEEPING A CLOSED LOW OFF THE CENTRAL CALIFORNIA COAST
THROUGH MONDAY. ECMWF/GEM ARE SLIGHTLY FURTHER EAST POSITIONING
TROUGH AXIS JUST INLAND INTO CALIFORNIA. OVER THE PAST FEW DAYS THE
ECMWF HAS BEEN TRENDING SLOWER. SO WHAT DOES ALL THAT MEAN FOR
SATURDAY THROUGH MONDAY. FAVORABLE MOISTURE AND INSTABILITY
PARAMETERS WILL CONTINUE TO LIE OVER LINCOLN...NORTHEAST CLARK AND
MOHAVE COUNTIES SATURDAY THROUGH MONDAY. FURTHER WEST...DECREASING
INSTABILITY ASSOCIATED UNDER COLD POOL ALOFT WILL AID IN THE
DEVELOPMENT OF ISOLATED SHOWERS/THUNDERSTORMS FOR THE EASTERN SLOPES
OF THE SOUTHERN SIERRA OF INYO COUNTY.
ON TUESDAY AND WEDNESDAY...GFS/GEM SHOW AN OPEN TROUGH INLAND ACROSS
THE WESTERN GREAT BASIN WHICH WOULD SUGGEST A DRYING TREND. THE
ECMWF IS THE OUTLIER SUGGESTING THE LOW OVER CENTRAL CALIFORNIA
WOULD WEAKEN WITH HIGH PRESSURE RETURNING TO THE AREA. THERE WOULD
BE ENOUGH RESIDUAL MID-LEVEL MOISTURE AROUND TO GENERATE CONVECTION
OVER THE MOUNTAINS WITH THE ECMWF SOLUTION. WITH DIFFERENCES STILL
OCCURRING MADE NO CHANGES TO TUESDAY AND WEDNESDAY AS WE AWAIT
BETTER MODEL AGREEMENT. DID LOWER HIGH TEMPERATURES A DEGREE OR TWO
OVER THE WEEKEND AS 00Z ECMWF NUMBERS NOT AS HIGH AS PREVIOUS RUNS.
IN FACT...THE CURRENT VALUES MAY STILL BE A DEGREE OR TWO TOO
WARM.
&&
.AVIATION...FOR MCCARRAN...SOUTHWEST WINDS THROUGH THIS MORNING
BEFORE TURNING TO THE SOUTHEAST AROUND 8-10 KTS AFTER 19Z. THESE
SOUTHEAST WINDS SHOULD CONTINUE THROUGH SUNSET BEFORE SHIFTING BACK
TO THE SOUTHWEST AROUND 8-10 KTS. FEW-SCT CLOUDS DEVELOPING THIS
AFTERNOON WITH ISOLATED THUNDERSTORMS AFFECTING THE PEACH SPRINGS
AND MORMON MESA CORRIDORS.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED THUNDERSTORMS OVER PORTIONS OF MOHAVE COUNTY
THROUGH TODAY WITH FEW-SCT CLOUDS AROUND 14K FEET ELSEWHERE. WINDS
WILL GENERALLY REMAIN UNDER 12 KTS AND FAVOR A EAST TO SOUTHEAST
DIRECTION FOR MUCH OF TODAY.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
GORELOW/PIERCE
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
944 AM CDT THU AUG 15 2013
.UPDATE...
LATEST HRRR IS SUPPORT OF DEVELOPING SOME SHOWER ACTIVITY ACROSS
MAINLY OUR SOUTH AND EASTERN AREAS. COLD FRONT THAT MOVED THROUGH
A COUPLE OF DAYS AGO IS NOW STALLED OUT JUST NORTH OF THE GULF
COAST. SFC TROUGH EXTENDS NORTHWARD THROUGH EASTERN TN.
MEANWHILE...SOME MID AND UPPER LEVEL TROUGHING IS NOTED ACROSS THE
SOUTHEAST. UPPER LEVEL AXIS TO SET UP JUST WEST OF THE MID STATE.
THIS WILL HELP TO KEEP JUST ENOUGH MOISTURE IN PLACE TO WARRANT
THE POTENTIAL FOR CONVECTION.
FOR THE FCST...CURRENT GRIDS LOOK TO BE IN GOOD SHAPE. CERTAINLY
MORE IN THE WAY OF CLOUDINESS CAN BE EXPECTED ACROSS THE EAST AND
SOUTH BUT PCLDY CONDITIONS SHOULD HOLD FOR THE MOST PART. ONLY
CHANGE WILL BE TO BUMP HIGH TEMPS BY JUST 1 DEGREE OR SO. UPDATE
OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 708 AM CDT THU AUG 15 2013/
UPDATE...FOR 12Z TAFS...
AVIATION...
VFR CONDITIONS EXPECTED THROUGHOUT THE TAF PERIOD FOR ALL SITES.
CHANCE OF SHOWERS WILL INCREASE FROM THE SOUTHEAST THIS
AFTERNOON...INTRODUCING VCSH AT CSV AROUND 00Z. BEST MOISTURE WILL
LIKELY REMAIN IN THE SOUTHERN AND EASTERN PORTIONS OF THE
AREA...SO KEPT PRECIP OUT OF CKV AND BNA FOR NOW.
PREV DISCUSSION... /ISSUED 323 AM CDT THU AUG 15 2013/
DISCUSSION...IT WAS AN UNUSUALLY COOL MORNING ACROSS THE MID
STATE WITH TEMPERATURES MOSTLY IN THE 50S. THE DRY AIR AND NEAR
RECORD COOL CONDITIONS WERE ASSOCIATED WITH A SURFACE HIGH
PRESSURE SYSTEM CENTERED OVER THE OHIO VALLEY. THIS BREAK FROM
SUMMER IS VERY TEMPORARY...AS DEEP MOISTURE SITTING SOUTHEAST OF
OUR AREA IS SET TO PUSH INTO THE MID STATE OVER THE NEXT COUPLE OF
DAYS.
MODELS ARE IN PRETTY GOOD AGREEMENT WITH A DEVELOPING MID/UPPER
TROUGH OVER THE MID MS AND TN VALLEY REGIONS OVER THE NEXT COUPLE
OF DAYS. AS THIS TROUGH DEVELOPS...AN INVERTED SURFACE TROUGH
OVER THE PLATEAU WILL INTENSIFY SLIGHTLY AND PULL WESTWARD...BRINGING
DEEPER MOISTURE ACROSS THE MID STATE. THIS WILL SET THE STAGE FOR
SCATTERED SHOWERS AND PERHAPS A FEW THUNDERSTORMS. THE FIRST
CHANCE FOR RAIN WILL DEVELOP OVER OUR SOUTHEAST COUNTIES THIS
AFTERNOON...JUST A 30 PERCENT CHANCE FOR SHOWERS. THE CHANCE FOR
SHOWERS WILL SPREAD ACROSS THE AREA TONIGHT INTO FRIDAY. ENOUGH
INSTABILITY WILL DEVELOP FOR ISOLATED THUNDERSTORM POTENTIAL
FRIDAY AFTERNOON.
THE CHANCE FOR SHOWERS AND STORMS WILL INCREASE INTO SATURDAY AS
THE UPPER TROUGH ADVANCES. WE ARE EXPECTING A PRETTY GOOD CHANCE
FOR SHOWERS...BUT NOT A TOTAL WASHOUT. THE COVERAGE OF SHOWERS
WILL DIMINISH SATURDAY NIGHT...THEN INCREASE AGAIN WITH DIURNAL
INFLUENCES ON SUNDAY. NO ORGANIZED OR WIDESPREAD SEVERE WX OR
EXCESSIVE RAINFALL IS EXPECTED THROUGH THIS FORECAST PERIOD.
BEYOND SUNDAY... THE TROUGH LIFTS OUT AND HEIGHTS BUILD ACROSS THE
REGION. A BERMUDA HIGH PATTERN DEVELOPS WITH TEMPERATURES AND
HUMIDITY LEVELS CLIMBING BACK TO TYPICAL SUMMER LEVELS. THERE WILL
BE GENERALLY SMALL CHANCES FOR DIURNALLY DRIVEN CONVECTION.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
220 PM CDT THU AUG 15 2013
.DISCUSSION...
949 AM CDT
VERY FEW CHANGES MADE TO THE GOING FORECAST THIS MORNING. A COUPLE
SHORT WAVES ARE PROGRESSING SOUTHEAST ACROSS NEBRASKA AND IOWA
THIS MORNING...WITH THE FURTHER EAST ONE GRADUALLY SHEARING OUT
FROM CENTRAL IA INTO FAR NW IL. THIS HAS AND WILL CONTINUE TO BE
RESPONSIBLE FOR THE HIGH CLOUDS WHICH THE RAP MODEL HAS A GOOD
HANDLE ON RIGHT NOW. HAVE GUIDED SKY GRIDS CLOSE TO ITS 500-600MB
RH PREDICTION AND THAT WAS IN LINE WITH EARLIER FORECAST
REASONING...KEEPING SOUTHERN AREAS NEAR YESTERDAYS HIGHS AND
SLIGHTLY WARMER IN THE NORTH. HAVE JUST ADJUSTED THE HOURLY
TEMPERATURE TRENDS SOME AS FAR NORTHERN AREAS MAY BE A LITTLE SLOW
TO CLIMB THIS MORNING GIVEN CURRENT CLOUD TRENDS. SOUTHWEST
BOUNDARY LAYER WINDS PER DOPPLER VAD AND SURFACE OBSERVATIONS HAVE
BEEN AROUND 10 KT IN NORTHEAST IL WHICH SHOULD BE ENOUGH TO
OFFSET THE LAKE BREEZE INTO EARLY AFTERNOON. THIS WIND SHIFT SHOULD
STILL DEVELOP AND PROGRESS INLAND FOR SOME COOLING. DID ADJUST UP
LAKESHORE HIGHS UPWARD DUE TO THE LATER EXPECTED DEVELOPMENT...WITH
DOWNTOWN CHICAGO LIKELY PEAKING SOMEWHERE IN THE 72 TO 74 RANGE.
MTF
//PREV DISCUSSION...
247 AM CDT
NOT MUCH CHANGE IN OVERALL FORECAST THINKING FROM PREVIOUS NIGHTS AS
HIGH PRESSURE CONTINUES TO PROVIDE QUIET WEATHER WITH A GRADUAL
WARMING TREND INTO EARLY NEXT WEEK AS IT DEPARTS. FOCUS WILL BE ON
FORECAST SUBTLETIES INCLUDING CLOUD COVER AND SOME MINIMAL PRECIP
CHANCES NEXT WEEK. EARLY MORNING WATER VAPOR IMAGERY SHOWS THE BIG
CLOSED UPPER LOW THAT ORIGINALLY BROUGHT THE UNSEASONABLY COOL AIR
TO THE REGION STILL SPINNING OVER JAMES BAY AND NORTHWESTERN
QUEBEC...WITH A SECONDARY LOW SPINNING OVER THE GULF OF ST.
LAWRENCE. UPPER RIDGING REMAINS STRETCHED FROM THE FOUR CORNERS INTO
ALBERTA/SASKATCHEWAN WITH A BIG UPPER LOW OFF THE BRITISH COLUMBIA
COAST MOVING NORTHWARD UP THE WESTERN FLANK OF THE RIDGE.
LOCALLY...THE AREA REMAINS UNDER A NORTHWESTERLY UPPER FLOW IN WHICH
SEVERAL SHORTWAVES ARE MOVING ACROSS THE PLAINS. AT THE
SURFACE...HIGH PRESSURE IS CENTERED OVER NORTHERN INDIANA AND
EXTENDS WEST INTO IOWA AND NORTH INTO THE CANADIAN PRAIRIES.
TODAY AND TONIGHT...THE SHORTWAVES NOTED ABOVE THAT ARE
TRAVERSING THE NORTHWEST UPPER FLOW OVER THE MID SECTION OF THE
COUNTRY WILL PRIMARILY STAY ON A TRAJECTORY TO TAKE THE MOST FOCUSED
FORCING SOUTHWEST OF THE CWA THROUGH FRIDAY. WATER VAPOR SHOWS A
DECENT INFLUX OF MID/HIGH LEVEL MOISTURE SPREADING EASTWARD ACROSS
THE MID AND UPPER MISSISSIPPI RIVER VALLEY WITH IR IMAGERY SHOWING
A LARGE AREA OF MID AND HIGH CLOUD DRIFTING ACROSS EASTERN
NEBRASKA/IOWA/MISSOURI. THE THICKER PORTION OF THIS BAND WILL LIKELY
MOVE ACROSS THE SOUTHERN CWA THROUGH THE MORNING WHILE THE HIGHER
AND THINNER NORTHERN EXTENT SPREADS ACROSS THE REMAINDER OF THE
AREA. BY AFTERNOON...FAR NORTHERN COUNTIES SHOULD SEE THE LEAST
COVERAGE WHILE SOUTHERN AREAS SEE AT LEAST SOME COVERAGE THROUGH
LATE DAY. WITH HIGH PRESSURE STILL CLOSE BY WINDS WILL BE LIGHT AND
MIXING WILL ONCE AGAIN BE WEAK...ESPECIALLY THANKS TO THE CLOUD
COVER. GIVEN THESE LIMITING FACTORS FOR MAX WARMING...WILL ADJUST
FORECAST HIGHS TO BE SIMILAR TO THOSE OF WEDNESDAY ACROSS THE
SOUTHERN CWA BUT MAINTAIN THE SLIGHT WARM UP OVER NORTHERN AREAS. A
LAKE BREEZE IS ONCE AGAIN EXPECTED THOUGH HAVE SOME QUESTION OF HOW
QUICKLY IT WILL DO SO GIVEN THE CLOUD COVER. LOW LEVEL FLOW IS SO
WEAK THOUGH THAT THERE DOES NOT LOOK TO BE A PROBLEM DEVELOPING ONE
IT MAY JUST TAKE LONGER TO MOVE INLAND. THIS MAY ALLOW LAKEFRONT
AREAS TO WARM UP A FEW DEGREES OVER WEDNESDAY AND REACH THE 70
DEGREE MARK. OTHERWISE...DO EXPECT SOME DIURNAL STRATOCU TO DEVELOP
UNDER THE MID AND HIGH CLOUDS THOUGH IT MAY BE A BIT MORE SCATTERED
IN COVERAGE THAN RECENT DAYS AND MAY TAKE A LITTLE LONGER TO
DEVELOP. SOME CIRRUS MAY LINGER SOUTH TONIGHT BUT OTHERWISE EXPECT
MOSTLY CLEAR SKIES AND LIGHT WINDS SO OVERNIGHT LOWS WILL ONCE AGAIN
BE IN THE 50S AWAY FROM THE URBAN HEAT ISLAND. A FEW OF THE
TRADITIONALLY COLDER SPOTS MAY FALL INTO THE UPPER 40S.
FRIDAY AND SATURDAY...AN UPPER TROUGH AXIS WILL BE AMPLIFYING FROM
LAKE MICHIGAN SOUTHWESTWARD THROUGH FRIDAY BUT THE BASE OF THE
TROUGH AND ASSOCIATED FORCING WILL REMAIN WELL TO THE SOUTH AND WEST
SO EXPECT A CONTINUATION OF DRY CONDITIONS. THE AIRMASS WILL MODIFY
SLIGHTLY WITH H85 TEMPS WARMING A FEW DEGREES WHICH WILL ALLOW HIGHS
TO WARM INTO THE MID AND UPPER 70S. EASTERLY FLOW WILL BE IN PLACE
SO LAKEFRONT AREAS WILL LIKELY BE HELD INTO THE LOWER 70S. EXPECT
SIMILAR CONDITIONS SATURDAY.
SUNDAY THROUGH WEDNESDAY...GUIDANCE CONTINUES TO STRUGGLE WITH THE
EVOLUTION OF THE NEWLY DEVELOPED UPPER TROUGH THAT WILL FOCUS OVER
THE LOWER MISSISSIPPI AND OHIO RIVER VALLEYS. THE IDEA OF THIS
TROUGH STAYING TO THE SOUTH THEN GRADUALLY WORKING ITS WAY
NORTHEASTWARD...KEEPING ASSOCIATED FORCING...MOISTURE AND RESULTANT
PRECIP CHANCES MAINLY TO THE SOUTH AND EAST OF THE AREA...HAS BEEN
CONSISTENT. WOULD NOT BE SURPRISED TO SEE SOME CONTINUED VARIATION IN
THE EVOLUTION OF THE TROUGH BUT WILL STICK WITH LITTLE IF ANY POP
MENTION FROM SUNDAY INTO EARLY NEXT WEEK. THE GRADUAL WARMING TREND
CONTINUES WITH HIGHS IN THE 80S EXPECTED BY SUNDAY AWAY FROM THE
LAKE. CONFIDENCE LOWERS BY THE MIDDLE OF NEXT WEEK BUT IT DOES
APPEAR THAT THE TROUGH WILL DEPART ALLOWING A PERIOD OF UPPER
RIDGING TO BUILD IN SUGGESTING A FURTHER WARMING OF TEMPS. THIS
WOULD ALSO KEEP PRECIP CHANCES TO THE NORTH...THOUGH IT WOULD NOT BE
OUT OF THE QUESTION FOR SOMETHING TO DEVELOP AS THE RIDGE
APPROACHES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NONE.
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE STRETCHING FROM THE MID MS VALLEY E TO THE DELMARVA
PENINSULA IS FORECASTED TO REMAIN OVER/VERY NEAR THE LOCAL AREA
THROUGH FRI...AND BEYOND. RESULT IS LIGHT WINDS THROUGH THE
FORECAST PERIOD...AND VERY LIGHT TO CALM TONIGHT INTO FRI MORNING.
WITH ONLY A SMALL DIFFERENCE IN SURFACE TEMPERATURES BETWEEN LAND
AND WATER ONLY EXPECT A WEAK LAKE BREEZE WITH VERY LITTLE MOMENTUM
TO PUSH IT VERY FAR INLAND. WINDS WILL REMAIN LIGHT WHETHER THE
LAKE BREEZE EVENTUALLY MAKES IT TO ORD OR MDW OR NOT DURING THE
REMAINDER OF THE DAY.
AN AREA OF CLODS AROUND 080 IS ASSOCIATED WITH A SHORT WAVE
CURRENTLY MOVING SE OVER THE IA- MO BOARDER WILL BE DECREASING AS
THE DISTURBANCE MOVES FURTHER AWAY DURING THE AFTERNOON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
HIGH ALL ELEMENTS EXCEPT FOR DIRECTION OF THE LIGHT WINDS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH MONDAY...VFR.
TUESDAY AND WEDNESDAY...SLIGHT CHANCE TSRA TUES NIGHT AND
WEDNESDAY.
RC
&&
.MARINE...
218 PM CDT
TRANQUIL CONDITIONS WILL CONTINUE OVER LAKE MICHIGAN THROUGH THE
WEEKEND. VARIABLE WINDS WILL BE SEEN AT TIMES ACROSS THE SOUTHERN
THIRD OF THE LAKE AS THE CANADIAN HIGH PRESSURE IN PLACE WILL HAVE
THE GREATEST INFLUENCE THERE...WITH REGIONAL LAKE BREEZES EACH
AFTERNOON AROUND THE LAKE PERIPHERY. SOUTHERLY WINDS WILL
GRADUALLY INCREASE ACROSS THE NORTHERN PART OF THE LAKE LATE IN
THE WEEKEND AND THEN EXPAND THEIR WAY SOUTHWARD EARLY NEXT WEEK AS
THE HIGH DEPARTS TO THE MID-ATLANTIC.
MTF
&&
.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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
108 PM CDT THU AUG 15 2013
.DISCUSSION...
949 AM CDT
VERY FEW CHANGES MADE TO THE GOING FORECAST THIS MORNING. A COUPLE
SHORT WAVES ARE PROGRESSING SOUTHEAST ACROSS NEBRASKA AND IOWA
THIS MORNING...WITH THE FURTHER EAST ONE GRADUALLY SHEARING OUT
FROM CENTRAL IA INTO FAR NW IL. THIS HAS AND WILL CONTINUE TO BE
RESPONSIBLE FOR THE HIGH CLOUDS WHICH THE RAP MODEL HAS A GOOD
HANDLE ON RIGHT NOW. HAVE GUIDED SKY GRIDS CLOSE TO ITS 500-600MB
RH PREDICTION AND THAT WAS IN LINE WITH EARLIER FORECAST
REASONING...KEEPING SOUTHERN AREAS NEAR YESTERDAYS HIGHS AND
SLIGHTLY WARMER IN THE NORTH. HAVE JUST ADJUSTED THE HOURLY
TEMPERATURE TRENDS SOME AS FAR NORTHERN AREAS MAY BE A LITTLE SLOW
TO CLIMB THIS MORNING GIVEN CURRENT CLOUD TRENDS. SOUTHWEST
BOUNDARY LAYER WINDS PER DOPPLER VAD AND SURFACE OBSERVATIONS HAVE
BEEN AROUND 10 KT IN NORTHEAST IL WHICH SHOULD BE ENOUGH TO
OFFSET THE LAKE BREEZE INTO EARLY AFTERNOON. THIS WIND SHIFT SHOULD
STILL DEVELOP AND PROGRESS INLAND FOR SOME COOLING. DID ADJUST UP
LAKESHORE HIGHS UPWARD DUE TO THE LATER EXPECTED DEVELOPMENT...WITH
DOWNTOWN CHICAGO LIKELY PEAKING SOMEWHERE IN THE 72 TO 74 RANGE.
MTF
//PREV DISCUSSION...
247 AM CDT
NOT MUCH CHANGE IN OVERALL FORECAST THINKING FROM PREVIOUS NIGHTS AS
HIGH PRESSURE CONTINUES TO PROVIDE QUIET WEATHER WITH A GRADUAL
WARMING TREND INTO EARLY NEXT WEEK AS IT DEPARTS. FOCUS WILL BE ON
FORECAST SUBTLETIES INCLUDING CLOUD COVER AND SOME MINIMAL PRECIP
CHANCES NEXT WEEK. EARLY MORNING WATER VAPOR IMAGERY SHOWS THE BIG
CLOSED UPPER LOW THAT ORIGINALLY BROUGHT THE UNSEASONABLY COOL AIR
TO THE REGION STILL SPINNING OVER JAMES BAY AND NORTHWESTERN
QUEBEC...WITH A SECONDARY LOW SPINNING OVER THE GULF OF ST.
LAWRENCE. UPPER RIDGING REMAINS STRETCHED FROM THE FOUR CORNERS INTO
ALBERTA/SASKATCHEWAN WITH A BIG UPPER LOW OFF THE BRITISH COLUMBIA
COAST MOVING NORTHWARD UP THE WESTERN FLANK OF THE RIDGE.
LOCALLY...THE AREA REMAINS UNDER A NORTHWESTERLY UPPER FLOW IN WHICH
SEVERAL SHORTWAVES ARE MOVING ACROSS THE PLAINS. AT THE
SURFACE...HIGH PRESSURE IS CENTERED OVER NORTHERN INDIANA AND
EXTENDS WEST INTO IOWA AND NORTH INTO THE CANADIAN PRAIRIES.
TODAY AND TONIGHT...THE SHORTWAVES NOTED ABOVE THAT ARE
TRAVERSING THE NORTHWEST UPPER FLOW OVER THE MID SECTION OF THE
COUNTRY WILL PRIMARILY STAY ON A TRAJECTORY TO TAKE THE MOST FOCUSED
FORCING SOUTHWEST OF THE CWA THROUGH FRIDAY. WATER VAPOR SHOWS A
DECENT INFLUX OF MID/HIGH LEVEL MOISTURE SPREADING EASTWARD ACROSS
THE MID AND UPPER MISSISSIPPI RIVER VALLEY WITH IR IMAGERY SHOWING
A LARGE AREA OF MID AND HIGH CLOUD DRIFTING ACROSS EASTERN
NEBRASKA/IOWA/MISSOURI. THE THICKER PORTION OF THIS BAND WILL LIKELY
MOVE ACROSS THE SOUTHERN CWA THROUGH THE MORNING WHILE THE HIGHER
AND THINNER NORTHERN EXTENT SPREADS ACROSS THE REMAINDER OF THE
AREA. BY AFTERNOON...FAR NORTHERN COUNTIES SHOULD SEE THE LEAST
COVERAGE WHILE SOUTHERN AREAS SEE AT LEAST SOME COVERAGE THROUGH
LATE DAY. WITH HIGH PRESSURE STILL CLOSE BY WINDS WILL BE LIGHT AND
MIXING WILL ONCE AGAIN BE WEAK...ESPECIALLY THANKS TO THE CLOUD
COVER. GIVEN THESE LIMITING FACTORS FOR MAX WARMING...WILL ADJUST
FORECAST HIGHS TO BE SIMILAR TO THOSE OF WEDNESDAY ACROSS THE
SOUTHERN CWA BUT MAINTAIN THE SLIGHT WARM UP OVER NORTHERN AREAS. A
LAKE BREEZE IS ONCE AGAIN EXPECTED THOUGH HAVE SOME QUESTION OF HOW
QUICKLY IT WILL DO SO GIVEN THE CLOUD COVER. LOW LEVEL FLOW IS SO
WEAK THOUGH THAT THERE DOES NOT LOOK TO BE A PROBLEM DEVELOPING ONE
IT MAY JUST TAKE LONGER TO MOVE INLAND. THIS MAY ALLOW LAKEFRONT
AREAS TO WARM UP A FEW DEGREES OVER WEDNESDAY AND REACH THE 70
DEGREE MARK. OTHERWISE...DO EXPECT SOME DIURNAL STRATOCU TO DEVELOP
UNDER THE MID AND HIGH CLOUDS THOUGH IT MAY BE A BIT MORE SCATTERED
IN COVERAGE THAN RECENT DAYS AND MAY TAKE A LITTLE LONGER TO
DEVELOP. SOME CIRRUS MAY LINGER SOUTH TONIGHT BUT OTHERWISE EXPECT
MOSTLY CLEAR SKIES AND LIGHT WINDS SO OVERNIGHT LOWS WILL ONCE AGAIN
BE IN THE 50S AWAY FROM THE URBAN HEAT ISLAND. A FEW OF THE
TRADITIONALLY COLDER SPOTS MAY FALL INTO THE UPPER 40S.
FRIDAY AND SATURDAY...AN UPPER TROUGH AXIS WILL BE AMPLIFYING FROM
LAKE MICHIGAN SOUTHWESTWARD THROUGH FRIDAY BUT THE BASE OF THE
TROUGH AND ASSOCIATED FORCING WILL REMAIN WELL TO THE SOUTH AND WEST
SO EXPECT A CONTINUATION OF DRY CONDITIONS. THE AIRMASS WILL MODIFY
SLIGHTLY WITH H85 TEMPS WARMING A FEW DEGREES WHICH WILL ALLOW HIGHS
TO WARM INTO THE MID AND UPPER 70S. EASTERLY FLOW WILL BE IN PLACE
SO LAKEFRONT AREAS WILL LIKELY BE HELD INTO THE LOWER 70S. EXPECT
SIMILAR CONDITIONS SATURDAY.
SUNDAY THROUGH WEDNESDAY...GUIDANCE CONTINUES TO STRUGGLE WITH THE
EVOLUTION OF THE NEWLY DEVELOPED UPPER TROUGH THAT WILL FOCUS OVER
THE LOWER MISSISSIPPI AND OHIO RIVER VALLEYS. THE IDEA OF THIS
TROUGH STAYING TO THE SOUTH THEN GRADUALLY WORKING ITS WAY
NORTHEASTWARD...KEEPING ASSOCIATED FORCING...MOISTURE AND RESULTANT
PRECIP CHANCES MAINLY TO THE SOUTH AND EAST OF THE AREA...HAS BEEN
CONSISTENT. WOULD NOT BE SURPRISED TO SEE SOME CONTINUED VARIATION IN
THE EVOLUTION OF THE TROUGH BUT WILL STICK WITH LITTLE IF ANY POP
MENTION FROM SUNDAY INTO EARLY NEXT WEEK. THE GRADUAL WARMING TREND
CONTINUES WITH HIGHS IN THE 80S EXPECTED BY SUNDAY AWAY FROM THE
LAKE. CONFIDENCE LOWERS BY THE MIDDLE OF NEXT WEEK BUT IT DOES
APPEAR THAT THE TROUGH WILL DEPART ALLOWING A PERIOD OF UPPER
RIDGING TO BUILD IN SUGGESTING A FURTHER WARMING OF TEMPS. THIS
WOULD ALSO KEEP PRECIP CHANCES TO THE NORTH...THOUGH IT WOULD NOT BE
OUT OF THE QUESTION FOR SOMETHING TO DEVELOP AS THE RIDGE
APPROACHES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NONE.
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE STRETCHING FROM THE MID MS VALLEY E TO THE DELMARVA
PENINSULA IS FORECASTED TO REMAIN OVER/VERY NEAR THE LOCAL AREA
THROUGH FRI...AND BEYOND. RESULT IS LIGHT WINDS THROUGH THE
FORECAST PERIOD...AND VERY LIGHT TO CALM TONIGHT INTO FRI MORNING.
WITH ONLY A SMALL DIFFERENCE IN SURFACE TEMPERATURES BETWEEN LAND
AND WATER ONLY EXPECT A WEAK LAKE BREEZE WITH VERY LITTLE MOMENTUM
TO PUSH IT VERY FAR INLAND. WINDS WILL REMAIN LIGHT WHETHER THE
LAKE BREEZE EVENTUALLY MAKES IT TO ORD OR MDW OR NOT DURING THE
REMAINDER OF THE DAY.
AN AREA OF CLODS AROUND 080 IS ASSOCIATED WITH A SHORT WAVE
CURRENTLY MOVING SE OVER THE IA- MO BOARDER WILL BE DECREASING AS
THE DISTURBANCE MOVES FURTHER AWAY DURING THE AFTERNOON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
HIGH ALL ELEMENTS EXCEPT FOR DIRECTION OF THE LIGHT WINDS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH MONDAY...VFR.
TUESDAY AND WEDNESDAY...SLIGHT CHANCE TSRA TUES NIGHT AND
WEDNESDAY.
RC
&&
.MARINE...
316 AM CDT
EXPANSIVE HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER
PATTERN ACROSS THE LAKE THROUGH THE WEEKEND. MODESTLY STRONG
SOUTHWEST WINDS OVER THE NORTH HALF EARLY THIS MORNING WILL SHIFT
WEST AND THEN RETURN TO SOUTHWEST THIS AFTERNOON WHILE
DIMINISHING. THE SOUTH HALF COULD SEE A BRIEF PERIOD THIS MORNING
WHEN WINDS SHIFT WEST AND GUST TO 20 KT BUT OTHERWISE SOUTHWEST
WINDS 15 KT OR LESS WILL DIMINISH FURTHER TONIGHT.
THEREAFTER...THE NORTH HALF WILL SEE AN EXTENDED PERIOD OF
SOUTHWEST WINDS OF 15 KT OR LESS AND THE SOUTH 10 KT OR LESS WITH
PERIODS OF VARIABLE WINDS UNTIL SUNDAY WHEN HIGH PRESSURE FINALLY
SHIFTS EAST. AS LOW PRESSURE TAKES SHAPE ACROSS THE CANADIAN
PRAIRIES AND PUSHES EAST SUNDAY NIGHT INTO MONDAY...THE TIGHTER
PRESSURE GRADIENT...ESPECIALLY OVER THE NORTH HALF...WILL RESULT
IN INCREASED SOUTHWEST WINDS. A WARM AIR MASS OVER THE LAKE BY
THAT TIME WILL LIKELY LIMIT MIXING AND GUSTS...BUT WINDS TO 25 KT
ARE POSSIBLE ACROSS THE FAR NORTH ON MONDAY.
RC
&&
.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:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
417 PM CDT THU AUG 15 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 339 PM CDT THU AUG 15 2013
MAIN FORECAST CHALLENGE IN THE SHORT TERM IS CLOUD COVER AND THE
POSSIBILITY OF ANY LIGHT SHRA/SPRINKLES THROUGH EARLY THIS EVENING.
OTHERWISE... QUIET WEATHER WILL CONTINUE TO BE THE THEME THROUGH
FRIDAY AS WE CONTINUE TO SLOWLY WARM WITH THE BUILDING UPPER RIDGE.
LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOWS THE ALL
TOO FAMILIAR PATTERN OF THE UPPER RIDGE TO OUR WEST AND UPPER TROUGH
TO OUR EAST. HOWEVER... FINALLY STARTING TO SEE SOME CHANGE IN
THIS... WHICH WILL GET FURTHER ACCELERATED NEXT WEEK AS RIDGE
BROADENS AND FLATTENS OVER THE CONUS AND EXERTS ITS MAIN PROMINENCE
OVER THE CENTER PART OF THE COUNTRY. IN THE MEANTIME... WE COULD SEE
SOME SHRA AND/OR SPRINKLES THROUGH EARLY THIS EVENING AS SOME
LINGERING LOW LEVEL INSTABILITY HELPS PRODUCE SOME TCU WITH PERHAPS
SOME PCPN MANAGING TO FALL OUT OF IT. WE WILL BEGIN TO GET INTO
RETURN FLOW ON FRIDAY AS THE SURFACE HIGH MOVES INTO THE EASTERN
GREAT LAKES... BUT ANY MEANINGFUL WARM ADVECTION WILL WAIT UNTIL
BEYOND THAT POINT. FRIDAY SHOULD BE SIMILAR... BUT SLIGHTLY
WARMER... THAN TODAY WITHOUT ANY SHRA/SPRINKLE CHANCE AS WARMER AIR
ALOFT AND ASSOCIATED SUBSIDENCE WORK INTO THE AREA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 PM CDT THU AUG 15 2013
MORE SUMMERLIKE PATTERN TAKES HOLD LATE IN THE WEEKEND AND LINGERS
THROUGHOUT THE WEEK. THE UPPER RIDGE OVER THE PLAINS CONTINUES TO
GRADUALLY EXPAND EASTWARD FRIDAY NIGHT THROUGH THE UPCOMING
WEEKEND. A DRY AND WARMING PATTERN IS EXPECTED OVER THE NEXT SEVEN
DAYS. SOME OF THE GUIDANCE DOES MANAGE TO GENERATE LIGHT
PRECIPITATION NEAR THEN MN/SD BORDER OVER THE WEEKEND ALONG A DIFFUSE
MID LEVEL BOUNDARY. THE MOISTURE MIGHT BE A BIT OVERDONE SO WILL
CONTINUE TO LEAVE DRY MENTION. BY SUNDAY...HIGHS WILL BE ABOVE
CLIMATE NORMALS WITH TEMPS IN THE 80S. AS MENTIONED IN OUR
DISCUSSION YESTERDAY...THE CENTRAL ATLANTIC RIDGE IS EXPECTED TO
DRIFT SOUTHWEST WITH TIME. THE ENSM FORECAST SUPPORTS THIS WITH
KEEPING POSITIVE HEIGHT ANOMALIES FARTHER SOUTH THROUGH THE END OF
THE MONTH. THIS DISPLACEMENT OF THE ATLANTIC RIDGE WILL ALLOW THE
PERSISTENT EAST COAST TROUGH /OUR LOCAL NORTHWEST FLOW/ A CHANCE
TO SHIFT EAST. THE MODELS COMING INTO MUCH BETTER AGREEMENT IN THE
EXTENDED. WHILE THE RIDGE DOES BECOME FLATTER EARLY NEXT WEEK AS A
SERIES OF SHORTWAVES TRACK JUST NORTH OF THE CANADIAN BORDER. A
BOUNDARY APPROACHES THE REGION ON MONDAY...BUT ALL MODELS DISSOLVE
THIS FEATURE NORTHWEST OF THE FORECAST AREA. THE OPERATIONAL GFS
AND TO SOME DEGREE THE ECMWF SHOW THE A GLIMPSE OF THE WARMING
TREND THIS WEEKEND WITH 80S...BUT THE WARM UP BEGINS IN EARNEST
EARLY NEXT WEEK. 850 MB TEMPS GET BACK UP INTO THE UPPER TEENS AND
LOWER 20S. GIVEN THE DRY ANTECEDENT CONDITIONS AND EXPECTED
BUILDING RIDGE...MID TO UPPER 80S SEEM EASILY OBTAINABLE NEXT
WEEK...AND WE SHOULD ONCE AGAIN SEE 90 DEGREES FOR THE FIRST TIME
IN OVER A MONTH. MIXING TO 850-750 MB WITH A SLIGHT SUPER
ADIABATIC LAYER GIVES NEAR RECORD TEMPS OF 95-99 DEGREES. SO...WE
WILL NEED TO MONITOR THE TEMP ADVECTION AND MIXING POTENTIAL.
CLOUD COVER ASIDE...THIS HAS A CHANCE TO BE A HOT STRETCH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1210 PM CDT THU AUG 15 2013
BENIGN AVIATION CONDITIONS WILL CONTINUE THROUGH THE UPCOMING
FORECAST PERIOD AS HIGH PRESSURE AT THE SURFACE DRIFTS ACROSS THE
AREA WHILE A RIDGE OF HIGH PRESSURE ALOFT CONTINUES TO SLOWLY
BUILD INTO THE UPPER MIDWEST. VFR FLIGHT CONDITIONS ARE EXPECTED
ALONG WITH LIGHT SOUTHERLY WINDS. THERE IS A SLIGHT POSSIBILITY
FOR A SHOWER THIS AFTERNOON INTO EARLY EVENING... BEFORE 03Z...
DUE TO SOME MARGINAL INSTABILITY. HOWEVER... ANY ACTIVITY WILL BE
VERY ISOLATED AND SHOULDN/T HAVE AN IMPACT ON FLIGHT CONDITIONS
GIVEN THE HIGH CLOUD BASES AND LIGHTNESS OF ANY PCPN. WITH THE
SLIM CHANCE AND LACK OF EXPECTED IMPACT TO CEILINGS AND
VISIBILITIES... KEPT THE MENTION OF ANYTHING OUT OF THE FORECASTS.
SHOULD SOMETHING POP UP... AND AMENDMENT COULD BE ISSUED.
KMSP...TAF REFLECTS EXPECTATIONS WITH LITTLE IN THE WAY OF
UNCERTAINTY OUTSIDE OF THE SLIM CHANCE OF A SHRA AS MENTIONED ABOVE.
/OUTLOOK FOR KMSP/
FRIDAY NIGHT THROUGH MONDAY NIGHT...VFR CONDITIONS EXPECTED. SOUTH
WIND 5 TO 15 KT THROUGH SATURDAY NIGHT... BECOMING SOUTHWEST 10 TO
20 KT SUNDAY THROUGH MONDAY NIGHT... WITH SPEEDS GENERALLY ON THE
LOW END OF THE RANGE AT NIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...TRH
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
333 PM CDT THU AUG 15 2013
.SYNOPSIS...
ISSUED AT 333 PM CDT THU AUG 15 2013
CURRENTLY...AN UPPER LEVEL DISTURBANCE IS MOVING SOUTH-SOUTHEAST
ACROSS SOUTH DAKOTA IN NORTHWEST FLOW ALOFT. AN UPPER LEVEL RIDGE
EXTENDS NORTHWARD FROM THE FOUR CORNERS REGION TO SASKATCHEWAN AND
AN UPPER LEVEL LOW EXISTS OVER QUEBEC. A SURFACE BOUNDARY
CURRENTLY EXTENDS NORTHWESTWARD FROM FRONTIER COUNTY THROUGH
GARDEN COUNTY AND INTO NORTHWESTERN NEBRASKA. ALSO...LOW CLOUDS
HAVE BEEN PERSISTENT OVER PARTS OF NORTH-CENTRAL NEBRASKA TODAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 333 PM CDT THU AUG 15 2013
STARTING TO SEE SOME CUMULUS DEVELOPMENT ALONG STATIONARY SURFACE
BOUNDARY EXTENDING TO THE NW FROM FRONTIER COUNTY THROUGH OGALLALA
AND NWWD. BELIEVE THIS WOULD BE THE BEST AREA FOR THUNDERSTORM
DEVELOPMENT THIS AFTERNOON...WITH ANY STORMS MOVING SOUTHEASTWARD
AT AROUND 20 KTS. MODELS INDICATE 0-6 KM SHEAR OF 30-35 KTS
ALTHOUGH SPC MESOANALYSIS DATA IS SHOWING SHEAR UNDER 30 KTS AS OF
20Z. THERE MAY BE A FEW ISOLATED SEVERE STORMS THIS AFTN/EVE...BUT
THE BEST CHANCE WOULD BE SOUTH OF I-80. HAVE TRIMMED POPS AND
THUNDERSTORM COVERAGE A BIT ACROSS THE AREA TONIGHT BASED ON
LATEST MODEL DATA AND TRENDS. HRRR MODEL FROM 18Z HAS A FEW STORMS
JUST WEST OF NORTH PLATTE AND AREAS SE...MOVING SE TONIGHT. EMC
WRF MODEL HAS A FAIR AMOUNT OF CONVECTION NORTH TO THE SD BORDER
HOWEVER...ALTHOUGH ITS NOT AS LIKELY. THUNDERSTORMS SHOULD COME TO
AN END IN THE EVENING ACROSS THE AREA AS THE UPPER LEVEL WAVE
MOVES THROUGH THE REGION. MODELS ARE POINTING TOWARD MORE FOG AND
LOW STRATUS TONIGHT...ESPECIALLY CENTRAL AND EAST. HAVE INCLUDED
FOG IN THE FORECAST FOR MOST OF THE AREA. TOMORROW...AFTER LOW
CLOUDS AND FOG HAVE DISSIPATED...FAIR SKIES AND TEMPS IN THE MID
70S EAST TO UPPER 80S WEST ARE EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 333 PM CDT THU AUG 15 2013
MID TERM...FRIDAY NIGHT THROUGH SUNDAY...RIDGING WILL CONTINUE TO
BUILD ACROSS THE CENTRAL PLAINS FRIDAY NIGHT THROUGH SATURDAY
NIGHT...WITH TEMPERATURES THE MAIN FORECAST CHALLENGE...FOLLOWED BY
PRECIPITATION CHANCES IN THE FAR WEST SUNDAY AFTERNOON. FOR FRIDAY
NIGHT...SURFACE HIGH PRESSURE WILL DRIFT EAST INTO THE MIDDLE
MISSISSIPPI VALLEY WITH A LEE SIDE TROUGH BEGINNING TO DEEPEN ACROSS THE
FRONT RANGES OF COLORADO AND WYOMING. SRLY WINDS WILL BEGIN TO
INCREASE LATE FRIDAY IN RESPONSE...AND ARE NOT EXPECTED TO TOTALLY
DECOUPLE FRIDAY NIGHT. THIS WILL LEAD TO SLIGHTLY WARMER MIN TEMPS
SATURDAY MORNING COMPARED TO FRIDAY MORNING. THE MET AND MAV
GUIDANCE ARE IN DECENT AGREEMENT WITH LOWS SATURDAY MORNING SO A
BLEND WILL BE UTILIZED...THEN SCALED UPWARD A DEGREE OR TWO DUE TO
INCREASED MIXING. MAV AND MET GUIDANCE TEMPS DIVERGE ON
SATURDAY...WITH THE MAV 3 TO 6 DEGREES COOLER THAN THE MUCH WARMER
MET. UTILIZED THE BIAS CORRECTED CONSALL GUIDANCE FOR HIGHS
SATURDAY...WHICH RESULTED IN A COMPROMISE BETWEEN THE MET AND MAV
NUMBERS. THIS LED TO HIGHS IN THE MIDDLE 80S IN THE EASTERN CWA...TO
THE LOWER 90S IN THE PANHANDLE...WHERE DEW POINTS IN THE LOWER 50S
ARE EXPECTED SAT AFTERNOON. FOR SUNDAY...HIGHS WILL MIRROR SATURDAYS
FCST...WITH THE EXCEPTION OF THE EASTERN ZONES WHERE SLIGHTLY WARMER
TEMPS ARE EXPECTED THANKS TO WARMER H85 AIR. HIGHS SUNDAY WILL RANGE
FROM THE UPPER 80S TO LOWER 90S IN THE PANHANDLE AND FAR WEST. BY
SUNDAY AFTERNOON...THE LATEST NAM IS HINTING AT BREAKING DOWN THE
RIDGE AND INITIATING CONVECTION ACROSS THE PANHANDLE AND FAR WESTERN
ZONES LATE SUNDAY AFTERNOON. THE LATEST GFS...KEEPS THIS CONVECTION
CONFINED TO THE FRONT RANGES OF COLORADO AND WYOMING...THANKS TO
VERY WEAK MID LEVEL STEERING WINDS. INHERITED FCST WAS DRY SUNDAY
AFTERNOON...AND INTEND TO KEEP IT THAT WAY...EVEN IN LIGHT OF THE
LATEST 12Z NAM SOLN.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...THERE ARE TWO SCHOOLS
OF THOUGHT WITH THE EXTENDED FCST...A...DRY AND VERY WARM CONDS
WILL PERSIST WELL INTO THE MIDDLE OF NEXT WEEK-12Z GFS...AND B...A
BREAK DOWN IN THE RIDGE ACROSS THE CENTRAL CONUS LEADING TO COOLER
AND WETTER CONDS ACROSS THE AREA-ECMWF. GLANCING AT LAST NIGHTS
ENSEMBLES...THE MEAN NCEP ENSEMBLE MEAN HAS A BREAKDOWN IN THE
WESTERN CONUS RIDGING EARLY IN THE WEEK WITH A FAIRLY ACTIVE
PATTERN DEVELOPING BY MIDWEEK. IN CONTRAST...THE OPERATIONAL GFS
FROM THIS MORNING HAS A CLOSED LOW OVER THE CENTRAL CA COAST. THE
LATTER SOLN...WOULD TEND TO FAVOR A DRY AND WARMER FCST AS RIDGING
WILL AMPLIFY DOWNSTREAM OF THE CLOSED CA LOW. NO SURPRISE...THE
LATEST MEX GUIDANCE FROM THIS MORNING HAS LOWER TO MIDDLE 90S FOR
HIGHS NEXT WEEK WITH DRY CONDS EXPECTED. SINCE THE OPERATIONAL GFS
IS KIND OF AN OUTLIER WITH THE ENSEMBLE FCSTS...WILL FAVOR COOLER
TEMPS IN THE 80S TO LOWER 90S FOR TEMPS NEXT WEEK. AS FOR PCPN
CHANCES...CAN`T SEE MORE THAN A 20 PCT CHANCE TOWARD THE MIDDLE OF
NEXT WEEK...AS WEAK DYNAMICS WILL CONTINUE WELL INTO NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1229 PM CDT THU AUG 15 2013
LOW CLOUDS HAVE HUNG IN OVER KVTN TODAY. WITH THE EASTERLY SURFACE
WIND...BELIEVE IT WILL CONTINUE TO BE SLOW TO ERODE IN THAT AREA.
THE CIG HAS BEEN VARIABLE AT 400 TO 800 FEET...SO IT IS STARTING
TO SHOW SIGNS OF LIFTING A BIT. NONETHELESS...BELIEVE BOTH KLBF
AND KVTN WILL SEE IFR CONDITIONS LATE TONIGHT WITH FOG/STRATUS
FORMING AS INDICATED BY THE BUFR SOUNDINGS/SREF/MOS GUIDANCE.
BELIEVE THIS AFTERNOON`S THUNDERSTORMS WILL AFFECT MAINLY KLBF AS
STRATUS AT KVTN WILL SLOW WARMING IN THAT AREA. WEST OF KVTN MAY
SEE TSRA HOWEVER.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...KNUTSVIG
SHORT TERM...KNUTSVIG
LONG TERM...CLB
AVIATION...KNUTSVIG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1259 PM CDT THU AUG 15 2013
.UPDATE...
ISSUED AT 652 AM CDT THU AUG 15 2013
NO SUBSTANTIAL CHANGES MADE TO THE FCST...BUT DID MAKE SOME
ADJUSTMENTS TO INCREASE SKY AND TIMING/LOCATION ADJUSTMENTS TO
POPS. ALSO DECREASED TEMPS THRU EARLY AFTN TO SUPPRESS THE DIURNAL
RISE...ACCOUNTING FOR RAIN AND CLOUDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 431 AM CDT THU AUG 15 2013
ALOFT: NW FLOW WILL CONT OVER THE PLAINS THRU TNGT...WITHIN AN
AMPLIFIED ROCKIES RIDGE/ERN USA TROF LGWV PATTERN. WV IMAGERY SHOWED
A WELL-DEFINED SHRTWV TROF OVER ERN MT/NERN WY. THIS TROF WILL CONT
MOVING SE TODAY AND WILL BE LOCATED ALONG THE KS/OK BORDER BY
DAYBREAK FRI.
SFC: 1024 MB HIGH PRES WAS OVER THE OH VALLEY EARLY THIS MRNG. THIS
HIGH WILL ESSENTIALLY EXPAND E INTO THE MID-ATLANTIC...REMAINING
FAIRLY STATIONARY. THE MAIN POLAR FRONT WILL ALSO REMAIN STALLED
WELL S OF THE FCST AREA...OVER TX AND THE GULF COAST STATES. AN E-W
ORIENTED SFC TROF WAS NOTED OVER NEB /ROUGHLY ALONG I-80/ AND ITS
WRN END WAS ATTACHED TO A WEAK LEE-SIDE LOW OVER THE PANHANDLE. THIS
TROF IS FCST TO REMAIN IN PLACE /UNLESS IT BECOMES MODULATED OR
PARTIALLY DESTROYED BY ON-GOING CONVECTION THIS MRNG/. MEANWHILE...
THE LEE-SIDE LOW WILL STRENGTHEN AND SLIDE DOWN THE HIGH PLAINS TO
BE NEAR PUB BY SUNSET.
FCST FOR TODAY IS ESSENTIALLY VARIABLE CLOUDS WITH APPARENTLY A
COUPLE DIFFERENT OPPORTUNITIES FOR TSTMS. CONVECTIVE EVOLUTION
REMAINS COMPLEX AND UNCERTAIN...ESPECIALLY THIS AFTN/EVNG DUE TO THE
ON-GOING CLUSTER OF TSTMS AND ITS INFLUENCE ON FUTURE DEVELOPMENTS.
EARLY THIS MRNG: FOR THE 3RD MRNG IN A ROW WE HAVE A SMALL MCS
APPROACHING AND EXPECT IT TO AFFECT AREAS W AND S OF THE TRI-CITIES
BETWEEN 5-9 AM. THIS WEEK HAS BEEN EXCELLENT FOR MUCH-NEEDED
RAINFALL.
THE 05Z HI-RES RAP AND 00Z WRF FROM THE SD SCHOOL OF MINES AND TECH
LOOK EXCELLENT COMPARED TO REALITY AND HOW THIS MRNG WILL EVOLVE.
THE SMALL MCS WILL CONT INTO THE FCST AREA...PROBABLY WEAKENING WITH
TIME. A FEW SHWRS/POSSIBLE THUNDER? WILL ALSO CONT TO DEVELOP WITHIN
THE LLJ INDUCED WAA/ISENTROPIC ASCENT AHEAD OF THE MCS.
WHAT HAPPENS AFTER THIS MCS DEPARTS REMAINS UP FOR GRABS. THE
REMNANT MCV WILL BE SE OF OUR KS COUNTIES THIS AFTN AND WILL NOT BE
A FACTOR. THE TRAILING OUTFLOW /AND ANY POSSIBLE DIFFERENTIAL
HEATING BOUNDARIES/ WILL NEED TO BE WATCHED FOR CONVECTIVE
INITIATION THIS AFTN...AS WELL AS WHATEVER IS LEFT OF THE E-W
ORIENTED SFC TROF. THE HI-RES RAP AND THE SYNOPTIC-SCALE MODELS FCST
TSTMS OVER THE PANHANDLE THIS MRNG /POSSIBLY THE SMALL TSTM
CLUSTERS CURRENTLY ON-GOING OVER ERN WY/NWRN SD?/ AND THEN INCREASE
IN COVERAGE THIS AFTN AS THEY HEAD SE INTO THE FCST AREA.
WHILE PWAT/S ON 00Z SOUNDINGS ARE ONLY NEAR NORMAL...THE FCST AREA
LIES IN A RIBBON OF DECENT LOW-LVL MSTR /DWPTS LOW-MID 60S/. THE NAM
HIGH TEMPS WERE TOO WARM GIVEN EXPECTED RAINFALL AND CLOUD COVER
TODAY. SO USED THE 03Z SREF MEAN MLCAPE WHICH SUGGESTS 1500-2500
J/KG WITH THE GREATEST VALUES S AND W OF THE TRI-CITIES. THAT COULD
BE TOO HIGH GIVEN THAT A PORTION OF THE INSOLATION THAT OCCURS THIS
AFTN WILL GO TO EVAPORATING RAINFALL...NOT TO MENTION LEFTOVER
CLOUDINESS WHICH WILL RETARD DIURNAL HEATING.
OVERALL TROPOSPHERIC WINDS WILL BE WEAK...BUT DIRECTIONAL SHEAR
/WITH SFC AND MID-LVL WINDS 180 APART/ WILL CONTRIBUTE TO 0-6 KM
SHEAR OF 30-40 KTS /HIGHEST OVER N-CNTRL KS/.
INDIVIDUAL CELL MOVEMENT WILL BE SE AT 15-20 KTS. ANY MULTICELL
CLUSTERS THAT FORM COULD MOVE UP TO 40 KTS THREATENING SOME WIND
DAMAGE. IF A SUPERCELL OR TWO FORMS...MOVEMENT WOULD BE SSW AROUND
20 KTS. HODOGRAPHS WILL BE NEARLY A STRAIGHT-LINE SUGGESTING
SUPERCELL SPLITS A POSSIBILITY.
MAIN THREATS: HAIL TO 1.75" AND STRAIGHT-LINE WINDS TO 60 MPH. AN
ISOLATED TORNADO CAN/T BE COMPLETELY RULED OUT W OF A LINE FROM
LEXINGTON NEB-HOLDREGE-OSBORNE KS...EITHER SUPERCELLULAR WITH 0-1
KM SRH OF 80-100 M2/S2 OR A NON-SUPERCELL TOR ASSOCIATED WITH ANY
BOUNDARIES.
TNGT: SVR TSTMS WILL PROBABLY BE ON-GOING DURING THE EVNG HRS...BUT
SHOULD BE S-SE OF THE FCST AREA BY MIDNGT. WINDS PROBABLY TURN
CALM /OR NEARLY CALM/ AFTER 2 AM. THIS THREATENS SOME FOG WHERE
SKIES CLEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 431 AM CDT THU AUG 15 2013
GUIDANCE SUGGESTS UPPER LEVEL RIDGING WILL PERSIST OVER THE WESTERN
CONUS THROUGH SUNDAY OR MONDAY...BEFORE MOVING EAST INTO PORTIONS OF
THE CENTRAL CONUS BY MID NEXT WEEK. AS A RESULT...NORTH TO
NORTHWESTERLY MID TO UPPER LEVEL FLOW IS EXPECTED OVER THE CENTRAL
PLAINS THROUGH MUCH OF THE LONG TERM FORECAST PERIOD...WITH THIS
FLOW SUBSTANTIALLY DECREASING IN INTENSITY AS THE UPPER LEVEL RIDGE
AXIS MOVES NEAR THE REGION BY EARLY TO MID NEXT WEEK. GIVEN THE
ANTICIPATED LACK IN KINEMATIC FORCING DURING THE EXTENDED FORECAST
PERIOD...AS SUGGESTED BY GUIDANCE...CHANCES FOR PRECIPITATION APPEAR
AS THOUGH THEY WILL REMAIN LOW. THERE SEEMS TO BE PRETTY GOOD
AGREEMENT BETWEEN THE NAM...EC...AND SREF-MEAN OF LINGERING
OVERNIGHT CONVECTION PERHAPS IMPACTING SOUTHERN AND EASTERN PORTIONS
OF OUR CWA FOR A TIME FRIDAY MORNING AND GIVEN THE ~20% POPS
INHERITED FROM THE PREVIOUS FORECAST...OPTED TO KEEP THE
SLIGHT-CHANCE POPS GOING FOR OUR SOUTH AND EAST 12-18Z FRIDAY.
BEYOND 18Z FRIDAY...THE ONLY CHANCE AT OBSERVING MEASURABLE
PRECIPITATION ACROSS THE AREA APPEARS AS THOUGH IT WILL REMAIN
RELEGATED TO THE LATTER PART OF THE LONG TERM FORECAST PERIOD AS THE
AXIS OF A 25-35KT 850MB JET STREAK SETS UP OVER THE AREA. LOW LEVEL
THERMAL ADVECTION ALONG THIS JET STREAK AXIS COULD PROMOTE ISOLATED
TO SCATTERED PRECIPITATION ACROSS THE AREA...A SOLUTION SUPPORTED BY
QPF FIELDS FROM THE OPERATIONAL GFS AND EC...ALTHOUGH IT IS WORTH
MENTIONING THAT THESE MODELS DO NOT AGREE ON WHICH DAYS OR WHICH
LOCATIONS ARE BETTER FAVORED FOR OBSERVING PRECIPITATION. ALLBLEND
RESPONDED BY PROVIDING ~20% POPS TO MUCH OF THE CWA MONDAY NIGHT
THROUGH WEDNESDAY AND GIVEN THE AFOREMENTIONED GUIDANCE...FELT THESE
POPS WERE JUSTIFIED AND THUS WERE LEFT UNCHANGED FOR THE MOST PART.
LITTLE CHANGE IN THE LOW LEVEL AIRMASS SHOULD PRESENT SIMILAR
TEMPERATURES ACROSS OUR AREA FRIDAY AND SATURDAY. PERSISTENT
SOUTHERLY LOW LEVEL FLOW AND RESULTANT THERMAL ADVECTION HOWEVER
SHOULD THEN ALLOW FOR A WARMING TREND DURING THE EARLY TO MID PART
OF NEXT WEEK. AS A RESULT...AFTERNOON HIGHS IN THE UPPER 70S TO LOW
80S ARE CURRENTLY FORECAST FRIDAY AND SATURDAY...WITH HIGHS CLIMBING
INTO THE MID TO UPPER 80S AND EVENTUALLY THE LOWER 90S TO FINISH OUT
THE LONG TERM FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1250 PM CDT THU AUG 15 2013
WENT WITH A FAIRLY PESSIMISTIC TAF THIS AFTERNOON AS THE LATEST
VISIBLE SATELLITE INDICATES IFR STRATUS IS EXPANDING SOUTHWARD.
ALREADY HAVE IFR CIGS AT ODX...AND USING EXTRAPOLATION...THIS
STRATUS SHOULD REACH KGRI AROUND 19Z. THEREAFTER...CONTINUE TO
EXPECT THE POTENTIAL FOR A VCTS LATE THIS AFTERNOON AS CONVECTION
ATTEMPTS TO BUILD ACROSS THE LOCAL AREA. HOWEVER...WITH STRATUS
AROUND THROUGH THE PEAK HEATING HOURS...DO NOT THINK CONVECTION
WILL BE WIDESPREAD NEAR OR NORTH OF THE TERMINAL...AND CONTINUED
WITH IMPROVING CIGS TO 4KFT AND ONLY A VCTS THROUGH THE EARLY
EVENING HOURS...MORE LIKELY IN RESPONSE TO SHORTWAVE DROPPING
SOUTH ACROSS SOUTH DAKOTA THIS AFTERNOON. ONCE SKIES BEGIN TO
CLEAR LATE TONIGHT...MODELS ARE INDICATING WE COULD SEE SOME DENSE
FOG FORM...AND DID INTRODUCE LIFR CIGS AND VSBYS FOR A FEW HOURS
TO ACCOUNT FOR THIS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...SAR
AREA FORECAST DISCUSSION UPDATE
NWS LAS VEGAS NV
1055 AM PDT THU AUG 15 2013
.SYNOPSIS...MOISTURE IS EXPECTED TO INCREASE OVER THE NEXT COUPLE OF
DAYS BRINGING ISOLATED THUNDERSTORMS TO PORTIONS OF MOHAVE COUNTY
TODAY. THUNDERSTORM COVERAGE IS FORECAST TO EXTEND FURTHER NORTH AND
EAST ON FRIDAY AS MONSOONAL MOISTURE INCREASES OVER THE REGION.
TEMPERATURES WILL INCREASE A COUPLE OF DEGREES TODAY...BUT MAY LOWER
A COUPLE OF DEGREES ON FRIDAY DUE TO THE ADDED CLOUD COVER.
TEMPERATURES ARE FORECAST TO REMAIN AROUND NORMAL FROM SATURDAY INTO
EARLY NEXT WEEK.
&&
.UPDATE...OBSERVATIONS SHOW AN INCREASE IN MOISTURE SOUTH AND EAST
OF LAS VEGAS...WITH DEWPOINTS UP APPROXIMATELY 25 DEGREES FROM
YESTERDAY MORNING AT LOCATIONS SUCH AS KINGMAN...NEEDLES...AND
BULLHEAD CITY. FARTHER NORTH AND WEST...THE VAST MAJORITY OF ANY
INCREASE IN MOISTURE IS LIMITED TO A LAYER BETWEEN 700-500MB. NO
MAJOR CHANGES WERE NEEDED THIS MORNING...OPTING TO KEEP ANY MENTION
OF CONVECTION TODAY LIMITED TO THE HIGHER ELEVATIONS OF EASTERN
MOHAVE COUNTY. THE MAIN REASON POPS WERE NOT INCREASED GIVEN THE
MOISTURE INCREASE IS A STRONG CAP NEAR 450MB...WHICH IS EXPECTED TO
PERSIST THROUGH THE DAY AND SO FAR...BASED ON SATELLITE IMAGERY...IS
HOLDING. -KENNEDY-
&&
.PREV DISCUSSION...
300 AM PDT THU AUG 15 2013
.SHORT TERM...HAD A FEW THUNDERSTORMS POP UP EARLY THIS MORNING OVER
FAR SOUTHERN MOHAVE COUNTY. HARD TO DISTINGUISH ANY FEATURES ON
SATELLITE...BUT THE RUC AND NEW NAM WAS SHOWING A WEAK AREA OF
VORTICITY PUSHING NORTHEAST THROUGH THAT GENERAL AREA. IT COULD ALSO
BE ENHANCED BY A WEAK JET STREAK PUSHING THROUGH SOUTHERN
NEVADA/NORTHWEST ARIZONA. IN EITHER CASE THE MODELS INDICATE A
GENERAL DOWNTREND TO THESE STORMS OVER THE NEXT FEW HOURS AS THESE
FEATURES MOVE EAST OF THE AREA. MOISTURE HAS BEEN ON THE GENERAL
INCREASE WITH PW SENSORS IN THE REGION SHOWING READINGS APPROACHING
AN INCH. ALTHOUGH MOISTURE WILL CONTINUE TO INCREASE TODAY THINK
THAT THINGS WILL BE A LITTLE TOO CAPPED TO GENERATE MUCH IN THE WAY
OF ANYTHING MORE THAN AN ISOLATED THUNDERSTORM OR TWO THIS
AFTERNOON...ESPECIALLY OUTSIDE OF FAR EASTERN MOHAVE COUNTY. WE WILL
CERTAINLY SEE AN INCREASE IN CLOUDS OVER THE REMAINDER OF MOHAVE AND
INTO CLARK COUNTY TODAY...BUT REALLY DONT EXPECT TO SEE THOSE
DEVELOP INTO STORMS. BETTER MOISTURE AND INSTABILITY LOOK TO ADVECT
INTO THE REGION FRIDAY AND IT LOOKS LIKE THUNDERSTORM CHANCES WILL
INCREASE. MODELS INDICATE PW VALUES INCREASING TO BETWEEN 1.00-1.25
INCHES OVER MUCH OF THE EASTERN HALF OF THE CWA ALONG WITH LI VALUES
BETWEEN 0/-2 AND A DECENT AMOUNT OF CAPE. HAVE GONE AHEAD AND RAISED
POPS ON FRIDAY INTO THE ISOLATED TO SCATTERED CATEGORY. ALTHOUGH
SOME STORMS ON FRIDAY COULD PRODUCE HEAVY RAIN...IT SEEMS THAT GUSTY
WINDS AND HAIL WILL BE THE PRIMARY CONCERN...ESPECIALLY OVER MOHAVE
COUNTY. TEMPERATURES WILL WARM A COUPLE OF DEGREES TODAY...BUT LOWER
SLIGHTLY ON FRIDAY AS MORE CLOUD COVER SHOULD KEEP READINGS DOWN.
.LONG TERM...SATURDAY THROUGH WEDNESDAY...MODELS DIVERGE AS EARLY AS
SATURDAY ON THEIR HANDLING OF SOUTHERN STREAM ENERGY APPROACHING THE
CENTRAL CALIFORNIA COAST. 00Z GFS/GFS ENSEMBLE MEAN ARE THE SLOWEST
SOLUTIONS KEEPING A CLOSED LOW OFF THE CENTRAL CALIFORNIA COAST
THROUGH MONDAY. ECMWF/GEM ARE SLIGHTLY FURTHER EAST POSITIONING
TROUGH AXIS JUST INLAND INTO CALIFORNIA. OVER THE PAST FEW DAYS THE
ECMWF HAS BEEN TRENDING SLOWER. SO WHAT DOES ALL THAT MEAN FOR
SATURDAY THROUGH MONDAY. FAVORABLE MOISTURE AND INSTABILITY
PARAMETERS WILL CONTINUE TO LIE OVER LINCOLN...NORTHEAST CLARK AND
MOHAVE COUNTIES SATURDAY THROUGH MONDAY. FURTHER WEST...DECREASING
INSTABILITY ASSOCIATED UNDER COLD POOL ALOFT WILL AID IN THE
DEVELOPMENT OF ISOLATED SHOWERS/THUNDERSTORMS FOR THE EASTERN SLOPES
OF THE SOUTHERN SIERRA OF INYO COUNTY.
ON TUESDAY AND WEDNESDAY...GFS/GEM SHOW AN OPEN TROUGH INLAND ACROSS
THE WESTERN GREAT BASIN WHICH WOULD SUGGEST A DRYING TREND. THE
ECMWF IS THE OUTLIER SUGGESTING THE LOW OVER CENTRAL CALIFORNIA
WOULD WEAKEN WITH HIGH PRESSURE RETURNING TO THE AREA. THERE WOULD
BE ENOUGH RESIDUAL MID-LEVEL MOISTURE AROUND TO GENERATE CONVECTION
OVER THE MOUNTAINS WITH THE ECMWF SOLUTION. WITH DIFFERENCES STILL
OCCURRING MADE NO CHANGES TO TUESDAY AND WEDNESDAY AS WE AWAIT
BETTER MODEL AGREEMENT. DID LOWER HIGH TEMPERATURES A DEGREE OR TWO
OVER THE WEEKEND AS 00Z ECMWF NUMBERS NOT AS HIGH AS PREVIOUS RUNS.
IN FACT...THE CURRENT VALUES MAY STILL BE A DEGREE OR TWO TOO
WARM.
&&
.AVIATION...FOR MCCARRAN...LIGHT WINDS WILL BECOME SOUTHEASTERLY BY
EARLY AFTERNOON AROUND 8-10 KTS. THESE SOUTHEAST WINDS SHOULD
CONTINUE THROUGH SUNSET BEFORE SHIFTING BACK TO THE SOUTHWEST AROUND
8-10 KTS. FEW-SCT CLOUDS DEVELOPING THIS AFTERNOON WITH ISOLATED
THUNDERSTORMS AFFECTING THE PEACH SPRINGS AND MORMON MESA CORRIDORS.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED THUNDERSTORMS OVER PORTIONS OF MOHAVE COUNTY
THROUGH TODAY WITH FEW-SCT CLOUDS AROUND 14K FEET ELSEWHERE. WINDS
WILL GENERALLY REMAIN UNDER 12 KTS AND FAVOR A EAST TO SOUTHEAST
DIRECTION FOR MUCH OF TODAY.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
GORELOW/PIERCE
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
203 PM CDT THU AUG 15 2013
.UPDATE...FOR 18Z TAFS.
&&
.AVIATION...
WEAK INVERTED LOW-LEVEL TROUGH SET TO SWING UP INTO THE PLATEAU
TODAY...THEN WORK WESTWARD TONIGHT. THIS WILL BEGIN SPREADING
DEEPER MOISTURE BACK INTO THE MID-STATE AND EVENTUALLY SHOWERS
WILL BEGIN TO DEVELOP...ESPECIALLY AFTER 12Z FRIDAY. INCREASED
MOISTURE WILL ALSO MVFR CIGS/VSBYS IN OVERNIGHT. LOW CIGS
OVERNIGHT SHOULD IMPROVE AFTER 14-15Z FRI.
&&
.PREV DISCUSSION... /ISSUED 944 AM CDT THU AUG 15 2013/
UPDATE...
LATEST HRRR IS SUPPORT OF DEVELOPING SOME SHOWER ACTIVITY ACROSS
MAINLY OUR SOUTH AND EASTERN AREAS. COLD FRONT THAT MOVED THROUGH
A COUPLE OF DAYS AGO IS NOW STALLED OUT JUST NORTH OF THE GULF
COAST. SFC TROUGH EXTENDS NORTHWARD THROUGH EASTERN TN.
MEANWHILE...SOME MID AND UPPER LEVEL TROUGHING IS NOTED ACROSS THE
SOUTHEAST. UPPER LEVEL AXIS TO SET UP JUST WEST OF THE MID STATE.
THIS WILL HELP TO KEEP JUST ENOUGH MOISTURE IN PLACE TO WARRANT
THE POTENTIAL FOR CONVECTION.
FOR THE FCST...CURRENT GRIDS LOOK TO BE IN GOOD SHAPE. CERTAINLY
MORE IN THE WAY OF CLOUDINESS CAN BE EXPECTED ACROSS THE EAST AND
SOUTH BUT PCLDY CONDITIONS SHOULD HOLD FOR THE MOST PART. ONLY
CHANGE WILL BE TO BUMP HIGH TEMPS BY JUST 1 DEGREE OR SO. UPDATE
OUT SHORTLY.
PREV DISCUSSION... /ISSUED 708 AM CDT THU AUG 15 2013/
UPDATE...FOR 12Z TAFS...
AVIATION...
VFR CONDITIONS EXPECTED THROUGHOUT THE TAF PERIOD FOR ALL SITES.
CHANCE OF SHOWERS WILL INCREASE FROM THE SOUTHEAST THIS
AFTERNOON...INTRODUCING VCSH AT CSV AROUND 00Z. BEST MOISTURE WILL
LIKELY REMAIN IN THE SOUTHERN AND EASTERN PORTIONS OF THE
AREA...SO KEPT PRECIP OUT OF CKV AND BNA FOR NOW.
PREV DISCUSSION... /ISSUED 323 AM CDT THU AUG 15 2013/
DISCUSSION...IT WAS AN UNUSUALLY COOL MORNING ACROSS THE MID
STATE WITH TEMPERATURES MOSTLY IN THE 50S. THE DRY AIR AND NEAR
RECORD COOL CONDITIONS WERE ASSOCIATED WITH A SURFACE HIGH
PRESSURE SYSTEM CENTERED OVER THE OHIO VALLEY. THIS BREAK FROM
SUMMER IS VERY TEMPORARY...AS DEEP MOISTURE SITTING SOUTHEAST OF
OUR AREA IS SET TO PUSH INTO THE MID STATE OVER THE NEXT COUPLE OF
DAYS.
MODELS ARE IN PRETTY GOOD AGREEMENT WITH A DEVELOPING MID/UPPER
TROUGH OVER THE MID MS AND TN VALLEY REGIONS OVER THE NEXT COUPLE
OF DAYS. AS THIS TROUGH DEVELOPS...AN INVERTED SURFACE TROUGH
OVER THE PLATEAU WILL INTENSIFY SLIGHTLY AND PULL WESTWARD...BRINGING
DEEPER MOISTURE ACROSS THE MID STATE. THIS WILL SET THE STAGE FOR
SCATTERED SHOWERS AND PERHAPS A FEW THUNDERSTORMS. THE FIRST
CHANCE FOR RAIN WILL DEVELOP OVER OUR SOUTHEAST COUNTIES THIS
AFTERNOON...JUST A 30 PERCENT CHANCE FOR SHOWERS. THE CHANCE FOR
SHOWERS WILL SPREAD ACROSS THE AREA TONIGHT INTO FRIDAY. ENOUGH
INSTABILITY WILL DEVELOP FOR ISOLATED THUNDERSTORM POTENTIAL
FRIDAY AFTERNOON.
THE CHANCE FOR SHOWERS AND STORMS WILL INCREASE INTO SATURDAY AS
THE UPPER TROUGH ADVANCES. WE ARE EXPECTING A PRETTY GOOD CHANCE
FOR SHOWERS...BUT NOT A TOTAL WASHOUT. THE COVERAGE OF SHOWERS
WILL DIMINISH SATURDAY NIGHT...THEN INCREASE AGAIN WITH DIURNAL
INFLUENCES ON SUNDAY. NO ORGANIZED OR WIDESPREAD SEVERE WX OR
EXCESSIVE RAINFALL IS EXPECTED THROUGH THIS FORECAST PERIOD.
BEYOND SUNDAY... THE TROUGH LIFTS OUT AND HEIGHTS BUILD ACROSS THE
REGION. A BERMUDA HIGH PATTERN DEVELOPS WITH TEMPERATURES AND
HUMIDITY LEVELS CLIMBING BACK TO TYPICAL SUMMER LEVELS. THERE WILL
BE GENERALLY SMALL CHANCES FOR DIURNALLY DRIVEN CONVECTION.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS AMARILLO TX
326 PM CDT THU AUG 15 2013
.DISCUSSION...
LITTLE OR NO CHANGES TO THE PREVIOUS GRIDS AND FORECAST AS THE
WEATHER PATTERN DOES NOT CHANGE MUCH. UPPER HIGH OVER THE FOUR
CORNERS AND SOUTHWESTERN STATES THROUGH THE WEEKEND WILL MAINTAIN A
NORTHWESTERLY UPPER FLOW TONIGHT...TRANSITIONING TO NORTHERLY BY
FRIDAY NIGHT AND SATURDAY. LOOKING AT THE TTU-WRF...NAM...GFS...AND
ECMWF...BETTER ORGANIZED CONVECTION COULD POSSIBLY HOLD OFF UNTIL
AROUND 00Z FRIDAY OR LATER. THE LATEST HRRR DEVELOPS CONVECTION
ACROSS THE NORTHWEST SECTIONS OF THE FORECAST AREA BY 20Z TODAY WHICH
THEN MOVES SOUTHEAST ACROSS THE WESTERN AND CENTRAL TEXAS PANHANDLE
AROUND 22Z TODAY TO AROUND 00Z TO 02Z FRIDAY. SINCE NOT MUCH
DEVELOPING AS OF 20Z TODAY ACROSS THE PANHANDLES...THINKING THAT THE
HRRR MAY BE THE ODD MODEL OUT. CONVECTION CURRENTLY OVER OKLAHOMA AND
EAST CENTRAL NEW MEXICO MOVING SOUTH AND SOUTHEAST. WILL CONTINUE TO
MONITOR TRENDS...BUT WITH CAPES FORECAST TO BE IN THE 1500 TO 2500
J/KG RANGE AND SURFACE DEW POINTS IN THE 60S...CANNOT RULE OUT
CONVECTION DEVELOPING PRIOR TO 00Z FRIDAY.
AS THE UPPER HIGH BROADENS OVER THE SOUTHWESTERN STATES OVER THE
WEEKEND...THE UPPER FLOW TRANSITIONS TO NORTHERLY AND EVEN
NORTHEASTERLY BRINGING A GRADUAL END TO THE CONVECTION BY SUNDAY.
WARMER AND DRIER CONDITIONS SUNDAY THROUGH NEXT WEDNESDAY WITH HIGHS
CLIMBING BACK UP INTO THE 90S.
SCHNEIDER
&&
.FIRE WEATHER...
AN UPPER RIDGE ACROSS THE FOUR CORNERS REGION AND THE SOUTHWESTERN
STATES WILL MAINTAIN A NORTHWESTERLY TO NORTHERLY UPPER FLOW ACROSS
THE PANHANDLES THROUGH THE WEEKEND. SHOWERS AND THUNDERSTORMS WILL
DEVELOP ACROSS SOUTHEASTERN AND EASTERN COLORADO AND WESTERN AND
SOUTHWESTERN KANSAS LATER TODAY AND TONIGHT AND WILL MOVE SOUTHEAST
ACROSS THE PANHANDLES. NO ELEVATED OR CRITICAL FIRE WEATHER
CONDITIONS ARE EXPECTED THROUGH THE MIDDLE OF NEXT WEEK AS MINIMUM
AFTERNOON RELATIVE HUMIDITIES REMAIN AT OR ABOVE 20 PERCENT THROUGH
THE MIDDLE OF NEXT WEEK.
SCHNEIDER
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 63 87 62 88 63 / 40 20 20 5 20
BEAVER OK 65 87 64 90 64 / 70 10 5 5 5
BOISE CITY OK 60 89 62 90 62 / 30 10 20 10 20
BORGER TX 66 89 67 90 66 / 50 10 10 5 10
BOYS RANCH TX 63 90 64 92 65 / 30 20 20 10 20
CANYON TX 62 88 61 89 63 / 40 20 20 5 20
CLARENDON TX 65 87 63 87 64 / 60 20 10 5 10
DALHART TX 59 89 62 90 61 / 30 10 20 10 20
GUYMON OK 62 89 64 90 63 / 50 10 10 5 10
HEREFORD TX 61 87 61 88 61 / 30 20 20 5 20
LIPSCOMB TX 63 85 63 87 64 / 70 10 10 5 5
PAMPA TX 63 85 62 86 62 / 50 10 10 5 10
SHAMROCK TX 63 87 62 86 63 / 70 20 10 5 5
WELLINGTON TX 65 88 64 89 65 / 70 20 10 5 5
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
13/11
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1244 PM CDT Thu Aug 15 2013
.UPDATE...
Increased POPS this afternoon.
&&
.DISCUSSION...
Isolated convection has formed across the Big Country early this
afternoon with agitated cumulus increasing in coverage, especially
northern and eastern sections. Latest HRRR develops scattered
convection across the area this afternoon within a moderately
unstable airmass and diminishing CIN. Given latest trends, POPS
were increased to 30 percent across the eastern half of the CWA
with slight chance elsewhere. Cannot rule out a strong storm or two
given an increase in shear aloft and modest instability. The main
threat from the stronger storms will be gusty winds with the
potential for isolated severe downbursts. Aviation discussion
follows.
&&
.AVIATION...
Predominantly a VFR forecast the next 24 hours. Scattered showers
and thunderstorms will develop across the area this afternoon.
Included VCTS at KABI, KJCT and KBBD where better coverage is
expected and will monitor convective trends for necessary amendments
this afternoon. Any storms will be capable of producing brief MVFR
conditions along with gusty winds. A complex of storms may approach
the KABI terminal from the north after 06Z tonight but confidence in
this scenario is too low to mention at this time.
&&
.PREV DISCUSSION... /ISSUED 625 AM CDT THU AUG 15 2013/
UPDATE...
See 12Z aviation discussion below.
AVIATION...
VFR conditions should prevail across most terminals for most of the
day. However, scattered thunderstorms will continue through the
period. Given the uncertain timing and location of the storms, not
going to mention in the forecast at this time. However, if a storm
does pass over a terminal, then a quick drop to MVFR or even briefly
IFR conditions will be likely. In addition, gusty winds and cloud to
ground lightning will pose a threat.
PREV DISCUSSION... /ISSUED 400 AM CDT THU AUG 15 2013/
SHORT TERM...
Today and Tonight.
Another chance of storms across the northwest Big Country this
morning, and across much of the Big Country again late tonight.
For the second night in a row, a complex of showers and storms is
moving southeast towards the Big Country this morning. Much like
earlier this morning, expect the activity to move southeast through
sunrise and then quickly weaken and dissipate by mid morning. Will
increase precipitation chances slightly across the area northwest of
Abilene, but will wait and see how much progress the storms make
before increasing them for the city itself.
Other showers and storms have lingered across the Northwest Hill
Country and the Northern Edwards Plateau early this morning. This
activity is much more scattered and has weakened quicker than the
storms farther north. At this point, will not boost pops in this
southern area, and assume that they will weaken and dissipate even
earlier, probably even before sunrise.
Large upper level high pressure will continue across the southwest
US, creating northwest and northerly flow through tonight. Models
have some differences in the possibilities of more storms late
tonight across the Big Country, with the NAM showing a potent
shortwave generating another MCS moving south into the area late
this evening and into the early morning hours. SPC is going along
with this scenario and has placed a small portion of the Big Country
into a Slight Risk for severe storms tonight. GFS is a little
farther east with the storm complex, and slower as well, not
bringing the rain into the area til near or after sunrise Friday
morning. Confidence in the storm complex is fairly high, but given
the uncertainty in the timing and track, will boost rain chances
mainly across Haskell and Throckmorton counties for now.
LONG TERM...
Friday through next Wednesday.
An MCS is expected to be diminishing across the northern part of the
area Friday morning. How far south the complex will make it isn`t
known...but it`s possible that it could be as far south as the
Concho Valley and Heartland areas before finally dissipating. This
argues for expanding the chance PoPs into the Concho Valley and
Heartland areas for Friday, but mainly for morning activity. This
complex would also likely leave an outflow boundary in the area for
new thunderstorm development by Friday afternoon...so will keep the
slight chance for showers and thunderstorms across the southern
areas of the CWA for Friday as well.
As flow aloft weakens through early next week, and the ridge expands
back over the area, we continue to expect a dry forecast through
next Tuesday with temperatures generally a few degrees above normal.
By the middle of next week...both the GFS and EC show the easterly
wave/trough currently in the western Caribbean moving into the Texas
gulf coast and toward west central Texas. At this time, the main
affect we will show is slightly cooler temperatures associated with
lower heights from this feature for Wednesday. However...should the
trough remain in tact into west central Texas, we may have another
chance for showers and thunderstorms by Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 92 71 95 69 92 / 30 20 30 20 5
San Angelo 94 71 97 70 94 / 20 20 20 20 5
Junction 95 72 98 71 95 / 30 20 20 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
24