Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/28/14
AREA FORECAST DISCUSSION
NWS FLAGSTAFF AZ
320 PM MST TUE AUG 25 2014
.SYNOPSIS...
A LOW PRESSURE TROUGH WILL CONTINUE TO BRING NUMEROUS SHOWERS AND
THUNDERSTORMS TO THE NORTHLAND TONIGHT. STORMS WILL DECREASE FROM
SOUTHWEST TO NORTHEAST OVERNIGHT...WITH SCATTERED STORMS EXPECTED
AGAIN ON WEDNESDAY AS THE LOW PRESSURE AREA PULLS AWAY FROM THE AREA.
A DRY WEST TO NORTHWEST FLOW WILL BRING DRY CONDITIONS AND SLIGHTLY
WARMER HIGH TEMPERATURES FROM THURSDAY THROUGH EARLY NEXT WEEK.
&&
.DISCUSSION...BRIEF DISCUSSION WITH ONGOING CONVECTIVE ACTIVITY...
NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPED OVER NORTHERN ARIZONA
TODAY...WITH THE STRONGEST ACTIVITY PERISTING SOUTH OF INTERSTATE 40
WHERE INSTABILITY HAS BEEN GREATEST. ACTIVITY HAS DIMINISHED OVER THE
PAST COUPLE HOURS OVER WESTERN AZ AS SUBSIDENCE AND DRIER AIR STARTS
TO WORK ON THE ATMOSPHERE...BUT EXPECT STORMS TO PERSIST AHEAD OF THE
SHORTWAVE AXIS WHERE INSTABILITY IN EXCESS OF 1000J/KG...AND 0-6KM
BULK SHEAR 30-40KTS WIND SHEAR STILL POSE A THREAT OF STRONG TO SVR
STORMS AND HEAVY RAINFALL. FLASH FLOOD WATCH TO CONTINUE AS ISSUED.
RECENT HRRR RUNS CONSISTENT WITH DOWNSWING IN ACTIVITY FROM SOUTHWEST
TO NORTHEAST ACROSS THE CWA THIS EVENING AS DRY AIR AND SUBSIDENCE
WORKS IN FROM THE WEST...WITH PRIMARY IMPACTS LIMITED TO NE AZ AFTER
06Z. CURRENT TRENDS SUPPORT THESE FORECASTS.
ON WEDNESDAY...LINGERING BOUNDARY LAYER MOISTURE WILL BE ADEQUATE FOR
SCATTERED SHOWERS AND THUNDERSTORMS TO REDEVELOP...MOST NUMEROUS OVER
AND NORTHEAST OF THE MOGOLLON RIM.
THURSDAY THROUGH THE WEEKEND...MODELS CONTINUE TO BE CONSISTENT WITH
STRONG RIDGING OVER THE SOUTHWEST...BRINGING FAIR AND WARM WEATHER
TO THE NORTHLAND THROUGH THE WEEKEND...AND INTO EARLY NEXT WEEK.
&&
.AVIATION...
FOR THE 00Z PACKAGE...SCT TO NMRS SHRA/TSRA AND ISOLD +TSRA WILL
PERSIST EAST OF A KPGA-KFGZ LINE 00-05Z...WITH -SHRA TO THE WEST.
STORMS WILL DECREASE FROM THE SOUTHWEST TO NORTHEAST 05Z-10Z. ISOLD
TO SCT SHRA/-TSRA WILL CONTINUE THROUGH 10Z-18Z WED GENERALLY NE OF
A LINE FROM KPGA-KRQE...WITH REDEVELOPMENT OF -TSRA OVR NRN AZ HIGHER
TERRAIN AFTER 18Z WED. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY EVENING
FOR AZZ004>008-015>018-037-038.
&&
$$
PUBLIC.........BAK
AVIATION.......BAK
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
145 PM MST TUE AUG 26 2014
.SYNOPSIS...
AFTER TODAY...STORM ACTIVITY WILL BEGIN TO TREND DOWNWARD OVER
ARIZONA AS A LOW PRESSURE SYSTEM STARTS TO SHIFT EASTWARD.
MUCH DRIER AIR WILL MOVE INTO THE REGION FROM THE NORTH WITH DRY
CONDITIONS EXPECTED THURSDAY THROUGH TUESDAY.
&&
.DISCUSSION...
A STRONG STORM PASSED THROUGH PARKER AROUND MIDDAY AND VERY STRONG
STORMS DEVELOPED JUST NORTH OF LA PAZ COUNTY SHORTLY THEREAFTER.
GOOD CAPE AIDED BY DYNAMICAL FORCING...ASSOCIATED WITH AN UPPER
LOW...CAME TOGETHER. MAIN DYNAMICAL FEATURE IS A JET CENTERED OVER
NORTHWEST ARIZONA. WITH SOME LIFT DRIVEN BY RIGHT ENTRANCE REGION
DYNAMICS STILL TO AFFECT AN AREA STRETCHING FROM PARKER TO
WICKENBURG THIS AFTERNOON...THE FLASH FLOOD WATCH WAS EXPANDED
THERE. THE WATCH WAS ALSO EXPANDED IN TIME TO END AT 5 PM AS HI RES
MODEL GUIDANCE INDICATES STORM ACTIVITY CONTINUING PAST 2
PM...MAINLY OVER SOUTHERN GILA COUNTY. ANOTHER FACTOR IN ADDITION TO
THE SLOWLY DEPARTING JET OVER NORTHWEST ARIZONA IS ANOTHER JET
STREAK ALREADY MOVING ACROSS SOUTHERN ARIZONA PER MODELS. HRRR WAS
SLOW TO CATCH ON TO LA PAZ AND MOHAVE COUNTY ACTIVITY AND OTHER HI
RES MODELS HAVE PRETTY MUCH MISSED IT. HOWEVER...LATEST HRRR SHOWS
ACTIVITY LINGERING OVER LA PAZ COUNTY THROUGH 23Z AND DECREASING
AFTER THAT. IT ALSO SHOWS NORTHERNMOST MARICOPA COUNTY AND GILA
COUNTY BEING ACTIVE WITH MORE SPOTTY ACTIVITY OVER PHOENIX AREA AND
PINAL COUNTY. STORMS WILL NOT ONLY HAVE THE CAPABILITY OF PRODUCING
HEAVY RAIN BUT THERE IS ENOUGH CAPE AND SHEAR...MAINLY WEST OF
PHOENIX...TO BE CONCERNED ABOUT SEVERE POTENTIAL. DYNAMICAL FORCING
SHIFTS NORTHEASTWARD TONIGHT. THIS COMBINED WITH LOSS OF SURFACE
HEATING WILL MEAN A DOWN TREND FOR STORM CHANCES TONIGHT.
WITH THE PASSAGE OF THE TROUGH AXIS WEDNESDAY MORNING...STRONG
SYNOPTIC SUBSIDENCE AND DRYING OF THE ENTIRE COLUMN WILL SURGE
SOUTHEAST THROUGHOUT THE ENTIRE FORECAST AREA. THOUGH SOME RESIDUAL
MOISTURE MAY LINGER IN THE EASTERN CWA WITH SFC-H7 MIXING RATIOS
HOLDING NEAR 11 G/KG...NOTABLE WARMING ALOFT WILL SEVERELY LIMIT
INSTABILITY AND HAVE RELEGATED SOME MODEST SLIGHT CHANCE POPS TO
HIGHER TERRAIN LOCATIONS. OTHERWISE...SEASONABLY STRONG RIDGING WILL
TAKE HOLD OVER THE LOS ANGELES BASIN WITH H5 HEIGHTS AROUND
594DM...AND DOWNSTREAM NWLY FLOW COMPLETELY SCOURING MOISTURE FAR
AWAY FROM THE LOCAL REGION. ONLY ADDING INSULT TO INJURY...A STRONG
WLY JET CORE WILL DESCEND INTO THE GREAT BASIN BY THE END OF THE
WEEKEND...FURTHER REINFORCING THE WESTERLY FLOW LOCALLY (THE
ANTITHESIS OF THE NORTH AMERICAN MONSOON SEASON FLOW) AND KEEPING
MOISTURE WELL REMOVED FROM THE AREA. GIVEN THE EXCELLENT MODEL
AGREEMENT OF THIS PATTERN MORE REMINISCENT OF LATE
SEPTEMBER...FORECAST CONFIDENCE IS VERY HIGH FOR THURSDAY AND BEYOND
OF COMPLETELY DRY WEATHER AND HIGH TEMPERATURES NEAR TO SLIGHTLY
ABOVE AVERAGE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL
UNFAVORABLE SOUTHWEST TO WEST STEERING FLOW WILL AFFECT THE CENTRAL
DESERTS THIS AFTERNOON AND OVERNIGHT TONIGHT...AND THE STRONGEST
FORCING WILL REMAIN NORTH OF THE PHOENIX AREA...AFFECTING THE
NORTHERN HALF OF THE STATE. STILL...THERE IS PLENTIFUL MOISTURE
LINGERING ACROSS THE CENTRAL DESERTS AND ISOLATED STORMS MAY DEVELOP
LATER THIS AFTERNOON AND PERSIST INTO THE EVENING HOURS. CONFIDENCE
IS TOO LOW TO MENTION THUNDER IN THE TAFS ATTM...WILL SIMPLY CARRY
SCT-BKN CUMULUS DECKS MAINLY FROM 7-10K FEET. SHOULD STORMS FORM
LATER THIS AFTERNOON THAT MAY AFFECT THE TERMINALS...UPDATES WILL BE
MADE TO THE TAFS. ALSO...SHOULD STORMS DEVELOP GUSTY OUTFLOW WINDS
AND BLOWING DUST MAY EVENTUALLY MOVE IN AND AFFECT THE TERMINALS BUT
AGAIN...CONFIDENCE IS TOO LOW TO MENTION THIS IN THE TAFS AT THIS
TIME. OTHERWISE EXPECT CLEARING BY EARLY OR MID EVENING AS A DRIER
MORE STABLE WESTERLY FLOW ALOFT MOVES INTO THE AREA.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
NO SIGNIFICANT AVIATION IMPACTS EXPECTED THIS AFTERNOON OR
EVENING...AS THE UPPER LOW TO OUR NORTH SHIFTS OFF TOWARDS THE EAST
AND A DRIER WESTERLY FLOW ALOFT MOVES INTO THE WESTERN DESERTS. BY
EARLY EVENING SKIES WILL BECOME CLEAR OR MOSTLY CLEAR...AND WINDS
WILL DECREASE TO MOSTLY AOB 12KT....FAVORING THE SOUTHWEST OR WEST.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG HIGH PRESSURE ALOFT WILL CONTINUE ACROSS SOUTHEAST CALIFORNIA
AND SOUTHERN ARIZONA FRIDAY INTO THE WEEKEND...KEEPING A DRY
NORTHWEST FLOW ACROSS THE AREA AND LEADING TO ABOVE NORMAL HIGH
TEMPERATURES. MINIMUM HUMIDITIES WILL BE ON THE LOW SIDE RANGING
MOSTLY FROM 10 TO 15 PERCENT ON FRIDAY AND SATURDAY. FOR SUNDAY INTO
EARLY NEXT WEEK...LOW PRESSURE ALOFT ACROSS THE PACIFIC NORTHWEST
WILL GRADUALLY STRENGTHEN SOUTHWARD LEADING TO INCREASING SOUTHWEST
OR WEST FLOW ALOFT. HIGH TEMPERATURES WILL SLOWLY FALL OFF TO BELOW
NORMAL VALUES BY NEXT TUESDAY. MINIMUM HUMIDITIES WILL STEADILY RISE
SUNDAY THROUGH TUESDAY WITH MANY DESERT LOCALES CLIMBING ABOVE 20
PERCENT. FAIR OVERNIGHT RECOVERIES FRIDAY NIGHT WILL GRADUALLY
INCREASE...BECOMING GOOD OR EXCELLENT BY EARLY NEXT WEEK. STRONG
WINDS ARE NOT EXPECTED DURING THE FIVE DAY PERIOD...HOWEVER LOCALLY
BREEZY CONDITIONS ARE POSSIBLE OVER THE WEEKEND WITH WINDS FAVORING
THE SOUTH TO SOUTHWEST DURING THE AFTERNOON AND EARLY EVENING HOURS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FLASH FLOOD WATCH UNTIL 5 PM THIS AFTERNOON AZZ021>022...AZZ024.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ/MO
AVIATION...CB
FIRE WEATHER...CB
AREA FORECAST DISCUSSION...CORRECTION
NWS PHOENIX AZ
1245 PM MST TUE AUG 26 2014
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
A WEATHER DISTURBANCE WILL PASS NORTH OF THE AREA TODAY HELPING PULL
MOISTURE NORTHWARD AND SUPPORTING INCREASED CHANCES FOR
THUNDERSTORMS. SOMEWHAT MORE WIDESPREAD RAINFALL COVERAGE IS LIKELY
TODAY COMPARED TO YESTERDAY...HOWEVER SOME LOCATIONS MAY MISS OUT ON
RAINFALL ALTOGETHER. STORMS THAT ARE MORE PERSISTENT WILL BE CAPABLE
OF PRODUCING VERY HEAVY RAINFALL. MUCH DRIER AND TRANQUIL WARM
WEATHER ARE ANTICIPATED FOR THE LATTER HALF OF THE WEEK.
&&
.DISCUSSION...
UPPER LOW CURRENTLY CENTERED OVER NEVADA HAS A VORT LOBE SWINGING
AROUND THE BOTTOM OF THE TROUGH OVER THE MOHAVE DESERT. THIS
FEATURE...AND THE ASSOCIATED JET DYNAMICS...HAS GENERATED SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OVER JOSHUA TREE NATIONAL PARK
AND PORTIONS OF EASTERN RIVERSIDE COUNTY WITH MOST OF THE ACTIVITY
TO THE NORTH AND NORTHEAST OVER SAN BERNARDINO COUNTY AND MOHAVE
COUNTY. MADE AN UPDATE TO THE FORECAST TO INCREASE POPS OVER EASTERN
RIVERSIDE/JTNP IN RESPONSE TO THE ONGOING SHOWER ACTIVITY AND TO
INCREASE THEM OVER LA PAZ COUNTY AS THE AREA OF FORCING TRANSLATES
EASTWARD. MAIN BRUNT SHOULD STILL BE NORTH OF OUR FORECAST AREA. WE
WILL NEED TO KEEP AN EYE OUT FOR LA PAZ AND NORTHWEST MARICOPA
COUNTY...IN ADDITION TO WHERE WE STILL HAVE THE FLASH FLOOD WATCH.
MAY NEED TO REINSERT THOSE AREAS INTO THE WATCH BUT WILL A BIT
LONGER TO SEE HOW THINGS UNFOLD. LATEST RUC INDICATES A PERSISTENT
BATCH OF FORCING OVER THE PHOENIX AREA THIS AFTERNOON WHICH APPEARS
TO BE ASSOCIATED WITH ANOTHER JET STREAK MOVING ACROSS THE CWA. BUT
12Z NAM AND GFS ARE NOT AS AGGRESSIVE. LOCAL HI RES MODELS FROM 06Z
RUNS KEEP PRECIP OUT OF OUR AREA ALMOST ENTIRELY BUT THEY HAVE NOT
PICKED UP ON THE ACTIVITY IN CALIFORNIA WHICH CALLS THEIR SOLUTIONS
INTO QUESTION. MADE A SUBTLE CHANGE TO PHOENIX AREA FORECAST TO
NUDGE DOWN TO SLIGHT CHANCES FOR THIS MORNING BUT UP TO CHANCE
CATEGORY FOR THIS AFTERNOON. IT IS CONCEIVABLE THAT THE
WATCH...CURRENTLY FOR ZONE 24...MAY NEED TO BE EXTENDED IN TIME. BUT
AGAIN...WILL WAIT A BIT LONGER TO SEE HOW THINGS UNFOLD.
&&
.PREVIOUS DISCUSSION ISSUED 700 AM...
DRY SLOT SUBSIDENCE CONTINUES TO DOMINATE MUCH OF THE FORECAST AREA
THIS MORNING...WITH 2 DISTINCT REGIONS OF ASCENT STRADDLING EITHER
SIDE OF THE CWA. THE MORE PREDOMINANT AREA IS AHEAD OF THE H5 COLD
CORE DESCENDING FROM CNTRL NEVADA...THOUGH THE MOST FAVORABLE AREA
OF LIFT WILL BE FOCUSED IN NORTHERN ARIZONA. A SECONDARY REGION OF
MORE SUBTLE ASCENT WITH A VERY WEAK WAVE OVER SERN ARIZONA MAY FOCUS
LIFT DOWNSTREAM OVER GILA COUNTY. THUS...HAVE CANCELLED THE FLASH
FLOOD WATCH FOR MUCH OF THE AREA...WITH ONLY SOME MODEST EXPECTATION
OF ANY DEVELOPMENT LATER IN THE DAY.
&&
.PREVIOUS DISCUSSION ISSUED 225 AM...
A VERY COMPLEX AND CHAOTIC ATMOSPHERIC STRUCTURE EARLY THIS MORNING
IS RESULTING IN A LOW CONFIDENCE FORECAST DESPITE NUMEROUS
INGREDIENTS PRESENT THAT WOULD SUGGEST AN OTHERWISE ACTIVE
CONVECTIVE PERIOD. FIRST...A WELL DEFINED POSITIVELY TILTED WAVE HAS
DESCENDED INTO CNTRL NEVADA WITH STRONGER JET ENERGY TRANSLATING
INTO THE EASTERN DOWNSTREAM SIDE OF THE WAVE ACROSS NORTHERN
ARIZONA. MEANWHILE...HURRICANE MARIE CONTINUES TO CHURN WELL
SOUTHWEST OF THE BAJA PENINSULA WITH OUTER FEEDER BANDS LOOPING INTO
THE SOUTHERN GULF OF CALIFORNIA. IN BETWEEN THESE TWO FEATURES...A
COL REGION HAS FORMED ALLOWING STRETCHING AND SHEARING OF ANY
SMALLER EASTERLY WAVES PROPAGATING THROUGH NORTHERN MEXICO. THIS COL
REGION IS ALSO NOTABLE FOR ITS STRONGER SUBSIDENCE...AND CURRENT
SATELLITE LOOPS CLEARLY SHOW THIS SUBSIDENT AREA AND DRY SLOT BEING
ADVECTED NORTHEAST INTO CNTRL ARIZONA BEHIND A SHORTWAVE BECOMING
ABSORBED INTO THE NORTHERN ARIZONA JET AXIS.
DESPITE THESE INHIBITING FEATURES...THERE ARE STILL SEVERAL OUTFLOW
BOUNDARIES...GRAVITY WAVES...AND SUBTLE EASTERLY WAVES THAT COULD
INVIGORATE RENEWED CONVECTION LATER THIS MORNING. ONE SUCH FEATURE
OVER SERN ARIZONA WAS ALLOWING PERSISTENT STORMS TO PERCOLATE OVER
GRAHAM COUNTY WITH SOME BACK BUILDING NOTED TOWARDS PIMA COUNTY.
SEVERAL BANDS OF ACCAS ALSO APPEAR EVIDENT THROUGH PARTS OF
PIMA...PINAL...AND MARICOPA COUNTIES...AND SHOULD SUFFICIENT LIFT
PRESENT ITSELF...A MARGINALLY UNSTABLE ENVIRONMENT (MUCAPES UP TO
1000 J/KG) AND JUICY ATMOSPHERE (PWATS NEAR 1.50 INCHES AND LOW
LEVEL MIXING RATIOS APPROACHING 15 G/KG) WOULD SUPPORT STORMS
PRODUCING HEAVY RAIN. HOWEVER...OPERATIONAL AND EXPERIMENTAL HIGH
RESOLUTION MODELS OFFER COMPLETELY MIXED SIGNALS AS TO THE EVOLUTION
OF FEATURES THIS MORNING RANGING FROM A COMPLETE DEARTH OF RAINFALL
TO NUMEROUS STORMS DEVELOPING OVER THE EASTERN CWA AROUND SUNRISE.
HAVE HEDGED THE POP FORECAST TOWARDS SREF MEANS...THOUGH BASED ON
RECENT SATELLITE AND RADAR TRENDS...PROSPECTS DO NOT APPEAR ALL THAT
FAVORABLE.
THE AFOREMENTIONED NEVADA LOW PRESSURE SYSTEM WILL PROPAGATE INTO
WRN UTAH THIS EVENING...WITH STRONGER FORCED JET ASCENT FOCUSED OVER
NORTHERN ARIZONA. TAKING INTO ACCOUNT ALL THE SYNOPTIC FEATURES AND
POTENTIAL MESOSCALE INFLUENCES...MUCH OF THE FORECAST AREA MAY STILL
REMAIN IN AN UNFAVORABLE SUBSIDENT REGION SOUTH OF THE JET AXIS IN
DEEPER SWLY FLOW. THE VAST PREPONDERANCE OF PROBABILISTIC ENSEMBLE
OUTPUT ALONG WITH DETERMINISTIC MODELS PAINT A RATHER DISMAL PICTURE
FOR PRECIPITATION CHANCES OUTSIDE OF HIGHER TERRAIN AREAS OF GILA
COUNTY. CANNOT COMPLETELY DISCOUNT THE ABYSMAL NUMERICAL GUIDANCE
POPS EITHER...AND HAVE ATTEMPTED TO REALLY TRIM POPS FOR LOWER
ELEVATION LOCATIONS THIS AFTERNOON. WILL KEEP THE FLASH FLOOD WATCH
VALID FOR THE TIME BEING GIVEN THE ATMOSPHERIC MOISTURE
PROFILES...THOUGH IF STORMS CANNOT BE GENERATED LOCALLY IT MAY BE
CANCELLED LATER THIS MORNING.
WITH THE PASSAGE OF THE TROUGH AXIS WEDNESDAY MORNING...STRONG
SYNOPTIC SUBSIDENCE AND DRYING OF THE ENTIRE COLUMN WILL SURGE
SOUTHEAST THROUGHOUT THE ENTIRE FORECAST AREA. THOUGH SOME RESIDUAL
MOISTURE MAY LINGER IN THE EASTERN CWA WITH SFC-H7 MIXING RATIOS
HOLDING NEAR 11 G/KG...NOTABLE WARMING ALOFT WILL SEVERELY LIMIT
INSTABILITY AND HAVE RELEGATED SOME MODEST SLIGHT CHANCE POPS TO
HIGHER TERRAIN LOCATIONS. OTHERWISE...SEASONABLY STRONG RIDGING WILL
TAKE HOLD OVER THE LOS ANGELES BASIN WITH H5 HEIGHTS AROUND
594DM...AND DOWNSTREAM NWLY FLOW COMPLETELY SCOURING MOISTURE FAR
AWAY FROM THE LOCAL REGION. ONLY ADDING INSULT TO INJURY...A STRONG
WLY JET CORE WILL DESCEND INTO THE GREAT BASIN BY THE END OF THE
WEEKEND...FURTHER REINFORCING THE WESTERLY FLOW LOCALLY (THE
ANTITHESIS OF THE NORTH AMERICAN MONSOON SEASON FLOW) AND KEEPING
MOISTURE WELL REMOVED FROM THE AREA. GIVEN THE EXCELLENT MODEL
AGREEMENT OF THIS PATTERN MORE REMINISCENT OF LATE
SEPTEMBER...FORECAST CONFIDENCE IS VERY HIGH FOR THURSDAY AND BEYOND
OF COMPLETELY DRY WEATHER AND HIGH TEMPERATURES NEAR TO SLIGHTLY
ABOVE AVERAGE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL
UNFAVORABLE SOUTHWEST TO WEST STEERING FLOW WILL AFFECT THE CENTRAL
DESERTS THIS AFTERNOON AND OVERNIGHT TONIGHT...AND THE STRONGEST
FORCING WILL REMAIN NORTH OF THE PHOENIX AREA...AFFECTING THE
NORTHERN HALF OF THE STATE. STILL...THERE IS PLENTIFUL MOISTURE
LINGERING ACROSS THE CENTRAL DESERTS AND ISOLATED STORMS MAY DEVELOP
LATER THIS AFTERNOON AND PERSIST INTO THE EVENING HOURS. CONFIDENCE
IS TOO LOW TO MENTION THUNDER IN THE TAFS ATTM...WILL SIMPLY CARRY
SCT-BKN CUMULUS DECKS MAINLY FROM 7-10K FEET. SHOULD STORMS FORM
LATER THIS AFTERNOON THAT MAY AFFECT THE TERMINALS...UPDATES WILL BE
MADE TO THE TAFS. ALSO...SHOULD STORMS DEVELOP GUSTY OUTFLOW WINDS
AND BLOWING DUST MAY EVENTUALLY MOVE IN AND AFFECT THE TERMINALS BUT
AGAIN...CONFIDENCE IS TOO LOW TO MENTION THIS IN THE TAFS AT THIS
TIME. OTHERWISE EXPECT CLEARING BY EARLY OR MID EVENING AS A DRIER
MORE STABLE WESTERLY FLOW ALOFT MOVES INTO THE AREA.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
NO SIGNIFICANT AVIATION IMPACTS EXPECTED THIS AFTERNOON OR
EVENING...AS THE UPPER LOW TO OUR NORTH SHIFTS OFF TOWARDS THE EAST
AND A DRIER WESTERLY FLOW ALOFT MOVES INTO THE WESTERN DESERTS. BY
EARLY EVENING SKIES WILL BECOME CLEAR OR MOSTLY CLEAR...AND WINDS
WILL DECREASE TO MOSTLY AOB 12KT....FAVORING THE SOUTHWEST OR WEST.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
STRONG HIGH PRESSURE ALOFT WILL CONTINUE ACROSS SOUTHEAST CALIFORNIA
AND SOUTHERN ARIZONA FRIDAY INTO THE WEEKEND...KEEPING A DRY
NORTHWEST FLOW ACROSS THE AREA AND LEADING TO ABOVE NORMAL HIGH
TEMPERATURES. MINIMUM HUMIDITIES WILL BE ON THE LOW SIDE RANGING
MOSTLY FROM 10 TO 15 PERCENT ON FRIDAY AND SATURDAY. FOR SUNDAY INTO
EARLY NEXT WEEK...LOW PRESSURE ALOFT ACROSS THE PACIFIC NORTHWEST
WILL GRADUALLY STRENGTHEN SOUTHWARD LEADING TO INCREASING SOUTHWEST
OR WEST FLOW ALOFT. HIGH TEMPERATURES WILL SLOWLY FALL OFF TO BELOW
NORMAL VALUES BY NEXT TUESDAY. MINIMUM HUMIDITIES WILL STEADILY RISE
SUNDAY THROUGH TUESDAY WITH MANY DESERT LOCALES CLIMBING ABOVE 20
PERCENT. FAIR OVERNIGHT RECOVERIES FRIDAY NIGHT WILL GRADUALLY
INCREASE...BECOMING GOOD OR EXCELLENT BY EARLY NEXT WEEK. STRONG
WINDS ARE NOT EXPECTED DURING THE FIVE DAY PERIOD...HOWEVER LOCALLY
BREEZY CONDITIONS ARE POSSIBLE OVER THE WEEKEND WITH WINDS FAVORING
THE SOUTH TO SOUTHWEST DURING THE AFTERNOON AND EARLY EVENING HOURS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FLASH FLOOD WATCH UNTIL 5 PM THIS AFTERNOON AZZ021>022...AZZ024.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...MO
AVIATION...CB
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
955 AM MST TUE AUG 26 2014
.SYNOPSIS...
A WEATHER DISTURBANCE WILL PASS NORTH OF THE AREA TODAY HELPING PULL
MOISTURE NORTHWARD AND SUPPORTING INCREASED CHANCES FOR
THUNDERSTORMS. SOMEWHAT MORE WIDESPREAD RAINFALL COVERAGE IS LIKELY
TODAY COMPARED TO YESTERDAY...HOWEVER SOME LOCATIONS MAY MISS OUT ON
RAINFALL ALTOGETHER. STORMS THAT ARE MORE PERSISTENT WILL BE CAPABLE
OF PRODUCING VERY HEAVY RAINFALL. MUCH DRIER AND TRANQUIL WARM
WEATHER ARE ANTICIPATED FOR THE LATTER HALF OF THE WEEK.
&&
.DISCUSSION...
UPPER LOW CURRENTLY CENTERED OVER NEVADA HAS A VORT LOBE SWINGING
AROUND THE BOTTOM OF THE TROUGH OVER THE MOHAVE DESERT. THIS
FEATURE...AND THE ASSOCIATED JET DYNAMICS...HAS GENERATED SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OVER JOSHUA TREE NATIONAL PARK
AND PORTIONS OF EASTERN RIVERSIDE COUNTY WITH MOST OF THE ACTIVITY
TO THE NORTH AND NORTHEAST OVER SAN BERNARDINO COUNTY AND MOHAVE
COUNTY. MADE AN UPDATE TO THE FORECAST TO INCREASE POPS OVER EASTERN
RIVERSIDE/JTNP IN RESPONSE TO THE ONGOING SHOWER ACTIVITY AND TO
INCREASE THEM OVER LA PAZ COUNTY AS THE AREA OF FORCING TRANSLATES
EASTWARD. MAIN BRUNT SHOULD STILL BE NORTH OF OUR FORECAST AREA. WE
WILL NEED TO KEEP AN EYE OUT FOR LA PAZ AND NORTHWEST MARICOPA
COUNTY...IN ADDITION TO WHERE WE STILL HAVE THE FLASH FLOOD WATCH.
MAY NEED TO REINSERT THOSE AREAS INTO THE WATCH BUT WILL A BIT
LONGER TO SEE HOW THINGS UNFOLD. LATEST RUC INDICATES A PERSISTENT
BATCH OF FORCING OVER THE PHOENIX AREA THIS AFTERNOON WHICH APPEARS
TO BE ASSOCIATED WITH ANOTHER JET STREAK MOVING ACROSS THE CWA. BUT
12Z NAM AND GFS ARE NOT AS AGGRESSIVE. LOCAL HI RES MODELS FROM 06Z
RUNS KEEP PRECIP OUT OF OUR AREA ALMOST ENTIRELY BUT THEY HAVE NOT
PICKED UP ON THE ACTIVITY IN CALIFORNIA WHICH CALLS THEIR SOLUTIONS
INTO QUESTION. MADE A SUBTLE CHANGE TO PHOENIX AREA FORECAST TO
NUDGE DOWN TO SLIGHT CHANCES FOR THIS MORNING BUT UP TO CHANCE
CATEGORY FOR THIS AFTERNOON. IT IS CONCEIVABLE THAT THE
WATCH...CURRENTLY FOR ZONE 24...MAY NEED TO BE EXTENDED IN TIME. BUT
AGAIN...WILL WAIT A BIT LONGER TO SEE HOW THINGS UNFOLD.
&&
.PREVIOUS DISCUSSION ISSUED 700 AM...
DRY SLOT SUBSIDENCE CONTINUES TO DOMINATE MUCH OF THE FORECAST AREA
THIS MORNING...WITH 2 DISTINCT REGIONS OF ASCENT STRADDLING EITHER
SIDE OF THE CWA. THE MORE PREDOMINANT AREA IS AHEAD OF THE H5 COLD
CORE DESCENDING FROM CNTRL NEVADA...THOUGH THE MOST FAVORABLE AREA
OF LIFT WILL BE FOCUSED IN NORTHERN ARIZONA. A SECONDARY REGION OF
MORE SUBTLE ASCENT WITH A VERY WEAK WAVE OVER SERN ARIZONA MAY FOCUS
LIFT DOWNSTREAM OVER GILA COUNTY. THUS...HAVE CANCELLED THE FLASH
FLOOD WATCH FOR MUCH OF THE AREA...WITH ONLY SOME MODEST EXPECTATION
OF ANY DEVELOPMENT LATER IN THE DAY.
&&
.PREVIOUS DISCUSSION ISSUED 225 AM...
A VERY COMPLEX AND CHAOTIC ATMOSPHERIC STRUCTURE EARLY THIS MORNING
IS RESULTING IN A LOW CONFIDENCE FORECAST DESPITE NUMEROUS
INGREDIENTS PRESENT THAT WOULD SUGGEST AN OTHERWISE ACTIVE
CONVECTIVE PERIOD. FIRST...A WELL DEFINED POSITIVELY TILTED WAVE HAS
DESCENDED INTO CNTRL NEVADA WITH STRONGER JET ENERGY TRANSLATING
INTO THE EASTERN DOWNSTREAM SIDE OF THE WAVE ACROSS NORTHERN
ARIZONA. MEANWHILE...HURRICANE MARIE CONTINUES TO CHURN WELL
SOUTHWEST OF THE BAJA PENINSULA WITH OUTER FEEDER BANDS LOOPING INTO
THE SOUTHERN GULF OF CALIFORNIA. IN BETWEEN THESE TWO FEATURES...A
COL REGION HAS FORMED ALLOWING STRETCHING AND SHEARING OF ANY
SMALLER EASTERLY WAVES PROPAGATING THROUGH NORTHERN MEXICO. THIS COL
REGION IS ALSO NOTABLE FOR ITS STRONGER SUBSIDENCE...AND CURRENT
SATELLITE LOOPS CLEARLY SHOW THIS SUBSIDENT AREA AND DRY SLOT BEING
ADVECTED NORTHEAST INTO CNTRL ARIZONA BEHIND A SHORTWAVE BECOMING
ABSORBED INTO THE NORTHERN ARIZONA JET AXIS.
DESPITE THESE INHIBITING FEATURES...THERE ARE STILL SEVERAL OUTFLOW
BOUNDARIES...GRAVITY WAVES...AND SUBTLE EASTERLY WAVES THAT COULD
INVIGORATE RENEWED CONVECTION LATER THIS MORNING. ONE SUCH FEATURE
OVER SERN ARIZONA WAS ALLOWING PERSISTENT STORMS TO PERCOLATE OVER
GRAHAM COUNTY WITH SOME BACK BUILDING NOTED TOWARDS PIMA COUNTY.
SEVERAL BANDS OF ACCAS ALSO APPEAR EVIDENT THROUGH PARTS OF
PIMA...PINAL...AND MARICOPA COUNTIES...AND SHOULD SUFFICIENT LIFT
PRESENT ITSELF...A MARGINALLY UNSTABLE ENVIRONMENT (MUCAPES UP TO
1000 J/KG) AND JUICY ATMOSPHERE (PWATS NEAR 1.50 INCHES AND LOW
LEVEL MIXING RATIOS APPROACHING 15 G/KG) WOULD SUPPORT STORMS
PRODUCING HEAVY RAIN. HOWEVER...OPERATIONAL AND EXPERIMENTAL HIGH
RESOLUTION MODELS OFFER COMPLETELY MIXED SIGNALS AS TO THE EVOLUTION
OF FEATURES THIS MORNING RANGING FROM A COMPLETE DEARTH OF RAINFALL
TO NUMEROUS STORMS DEVELOPING OVER THE EASTERN CWA AROUND SUNRISE.
HAVE HEDGED THE POP FORECAST TOWARDS SREF MEANS...THOUGH BASED ON
RECENT SATELLITE AND RADAR TRENDS...PROSPECTS DO NOT APPEAR ALL THAT
FAVORABLE.
THE AFOREMENTIONED NEVADA LOW PRESSURE SYSTEM WILL PROPAGATE INTO
WRN UTAH THIS EVENING...WITH STRONGER FORCED JET ASCENT FOCUSED OVER
NORTHERN ARIZONA. TAKING INTO ACCOUNT ALL THE SYNOPTIC FEATURES AND
POTENTIAL MESOSCALE INFLUENCES...MUCH OF THE FORECAST AREA MAY STILL
REMAIN IN AN UNFAVORABLE SUBSIDENT REGION SOUTH OF THE JET AXIS IN
DEEPER SWLY FLOW. THE VAST PREPONDERANCE OF PROBABILISTIC ENSEMBLE
OUTPUT ALONG WITH DETERMINISTIC MODELS PAINT A RATHER DISMAL PICTURE
FOR PRECIPITATION CHANCES OUTSIDE OF HIGHER TERRAIN AREAS OF GILA
COUNTY. CANNOT COMPLETELY DISCOUNT THE ABYSMAL NUMERICAL GUIDANCE
POPS EITHER...AND HAVE ATTEMPTED TO REALLY TRIM POPS FOR LOWER
ELEVATION LOCATIONS THIS AFTERNOON. WILL KEEP THE FLASH FLOOD WATCH
VALID FOR THE TIME BEING GIVEN THE ATMOSPHERIC MOISTURE
PROFILES...THOUGH IF STORMS CANNOT BE GENERATED LOCALLY IT MAY BE
CANCELLED LATER THIS MORNING.
WITH THE PASSAGE OF THE TROUGH AXIS WEDNESDAY MORNING...STRONG
SYNOPTIC SUBSIDENCE AND DRYING OF THE ENTIRE COLUMN WILL SURGE
SOUTHEAST THROUGHOUT THE ENTIRE FORECAST AREA. THOUGH SOME RESIDUAL
MOISTURE MAY LINGER IN THE EASTERN CWA WITH SFC-H7 MIXING RATIOS
HOLDING NEAR 11 G/KG...NOTABLE WARMING ALOFT WILL SEVERELY LIMIT
INSTABILITY AND HAVE RELEGATED SOME MODEST SLIGHT CHANCE POPS TO
HIGHER TERRAIN LOCATIONS. OTHERWISE...SEASONABLY STRONG RIDGING WILL
TAKE HOLD OVER THE LOS ANGELES BASIN WITH H5 HEIGHTS AROUND
594DM...AND DOWNSTREAM NWLY FLOW COMPLETELY SCOURING MOISTURE FAR
AWAY FROM THE LOCAL REGION. ONLY ADDING INSULT TO INJURY...A STRONG
WLY JET CORE WILL DESCEND INTO THE GREAT BASIN BY THE END OF THE
WEEKEND...FURTHER REINFORCING THE WESTERLY FLOW LOCALLY (THE
ANTITHESIS OF THE NORTH AMERICAN MONSOON SEASON FLOW) AND KEEPING
MOISTURE WELL REMOVED FROM THE AREA. GIVEN THE EXCELLENT MODEL
AGREEMENT OF THIS PATTERN MORE REMINISCENT OF LATE
SEPTEMBER...FORECAST CONFIDENCE IS VERY HIGH FOR THURSDAY AND BEYOND
OF COMPLETELY DRY WEATHER AND HIGH TEMPERATURES NEAR TO SLIGHTLY
ABOVE AVERAGE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL
VERY LOW CONFIDENCE FORECAST AS THE CURRENT ENVIRONMENT IS
UNFAVORABLE FOR STORM DEVELOPMENT...YET THE AIRMASS IS VERY MOIST
AND MARGINALLY UNSTABLE. HAVE REMOVED VCTS MENTION FOR THE TIME
BEING BASED ON CURRENT TRENDS...THOUGH NOT OUT OF THE QUESTION TO
SEE ISOLD/SCT TSRA AROUND THE TERMINAL SITES LATER THIS MORNING.
WINDS DIRECTIONS MAY ALSO BECOME QUITE VARIABLE THROUGH THE MORNING
HOURS...THOUGH SHOULD GENERALLY FAVOR A SE COMPONENT BEFORE BECOMING
MORE SWLY IN THE AFTERNOON.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
ONLY PERIODIC HIGH CLOUDS EXPECTED THROUGH WEDNESDAY MORNING WITH
ANY STORMINESS LIKELY REMAINING NORTH OF THE AREA. SFC WINDS SHOULD
RETAIN A SLY COMPONENT AT KBLH...WITH MORE VARIABILITY AT KIPL.
OVERALL...NO AVIATION IMPACTS EXPECTED.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
STRONG HIGH PRESSURE ALOFT AND WESTERLY FLOW IS WILL KEEP MONSOON
MOISTURE WELL REMOVED FROM THE DISTRICT...WITH MOSTLY CLEAR SKIES
THROUGH THE ENTIRE PERIOD. TEMPERATURES WILL REMAIN AT OR SLIGHTLY
ABOVE SEASONAL NORMALS WITH MAINLY LIGHT WINDS...THOUGH SOME
AFTERNOON GUSTS CAN BE EXPECTED NEAR UPSLOPE REGIONS. AFTERNOON
HUMIDITIES WILL FALL INTO THE SINGLE DIGITS AND TEENS ACROSS THE
LOWER DESERTS...WITH SOMEWHAT MORE MOIST CONDITIONS ACROSS THE
HIGHER TERRAIN OF GILA COUNTY. OVERNIGHT RECOVERY WILL GENERALLY BE
GOOD.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FLASH FLOOD WATCH UNTIL 2 PM THIS AFTERNOON AZZ024.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...MO
AVIATION...MO
FIRE WEATHER...PERCHA/MO
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1100 PM PDT MON AUG 25 2014
NEW AVIATION DISCUSSION
.SYNOPSIS...
SLIGHTLY BELOW NORMAL DAYTIME HIGHS ARE EXPECTED AGAIN ON TUESDAY
WITH A TROUGH OF LOW PRESSURE OVERHEAD. A SIGNIFICANT WARM UP IS
EXPECTED FOR THE SECOND HALF OF THE WEEK AS A RIDGE OF HIGH
PRESSURE DEVELOPS. THE HIGH PRESSURE WILL ALSO RESULT IN A
SHRINKING OF THE MARINE LAYER AND LESS NIGHT THROUGH MORNING LOW
CLOUD COVERAGE. A COOLING TREND IS THEN LIKELY INTO EARLY NEXT
WEEK.
&&
.UPDATE...
ONSHORE FLOW IS WEAKENING THIS EVENING EVEN AS TROUGH APPROACHES
THE AREA. WATER VAPOR IMAGERY INDICATES A TROUGH OF LOW PRESSURE
CONTINUING TO DIG INTO THE GREAT BASIN THIS EVENING. A DECENT
CLOUD SHIELD CAN BE SEEN OVER THE SAN JOAQUIN VALLEY ASSOCIATED
WITH THE TROUGH. HOWEVER...THE TROUGH IS DOING BATTLE WITH A
STRONG RIDGE OF HIGH PRESSURE OVER THE BIG BEND OF TEXAS. MODEL
SOLUTIONS ALL SUGGEST THE HIGH PRESSURE SYSTEM WINNING OUT. WITH
WEAKENING ONSHORE FLOW...THE MARINE LAYER DEPTH CONTINUES TO THIN
WITH THE LATEST AMDAR SOUNDINGS FROM KLAX INDICATING A DEPTH
AROUND 1100 FEET THIS EVENING. WITH LESS ONSHORE FLOW AND A
THINNER MARINE LAYER...A SLIGHT WARM UP SHOULD OCCUR ON TUESDAY.
THE CURRENT PACKAGE ADDRESS THE WARMING FOR TUESDAY REASONABLY.
AS THE TROUGH BRUSHES THE AREA...SOME MIDDLE AND HIGH LEVEL CLOUDS
WILL LIKELY RESULT. 13-KM RAP MODEL SOLUTIONS SUGGEST A NARROW
WINDOW FOR CONVECTIVE STORMS ON TUESDAY OVER THE EASTERN SAN
GABRIEL RANGE...BUT ALL OTHER MODEL SOLUTIONS KEEP THE CONVECTIVE
POTENTIAL TO THE EAST OF THE AREA. SOME CLOUDS HAVE BEEN ADDED FOR
THE SAN GABRIEL RANGE. WITH CONFIDENCE LOW IN THE MODEL SOLUTIONS
AT THIS TIME...NO MENTION OF CONVECTIVE SHOWERS WAS ADDED FOR THE
EASTERN SAN GABRIEL RANGE FOR TUESDAY.
&&
.PREV DISCUSSION...
SHORT TERM...ONSHORE PRESSURE WEAKEN FURTHER INTO WEDNESDAY...AND
HOLD COURSE ON THURSDAY. AS A RESULT...WE SHOULD SEE A MORE
NOTICEABLE WARMUP ON WEDNESDAY AND THURSDAY AS THE RIDGE PEAKS.
BY WEDNESDAY AND THURSDAY...THE INVERSION WILL STRENGTHEN WHICH
SHOULD KEEP CLOUDS OUT OF THE VALLEYS AND MAY EVEN KEEP CLOUDS OFF
SOME OF THE COASTS. CURRENT COASTAL TEMPERATURE FORECASTS ARE
CONSERVATIVE FACTORING IN THE MARINE LAYER UNCERTAINTY...AND
TEMPERATURES MAY END UP A FEW DEGREES HIGHER IF STRATUS INDEED
STAYS AWAY. DENSE FOG MAY BE A CONCERN AS WELL.
THE OTHER WRINKLE IS INCREASING NORTHWEST FLOW THURSDAY AND THURSDAY
NIGHT. AT THIS POINT EXPECTING A NEAR ADVISORY SUNDOWNER OVER SBA
COUNTY. THIS SHOULD KEEP CLOUDS OUT OF SRN SBA AND VENTURA
COUNTY...AND REALLY HEAT UP THE SOUTH COAST...MAYBE EVEN APPROACHING
HIGH TEMPERATURE RECORDS. IF A COASTAL EDDY ENDS UP FORMING FROM
THIS...LA COUNTY COULD SEE SOME COOLING STRATUS FORM.
FOR UP COMING SURF EVENT...SEE BEACHES SECTION BELOW.
LONG TERM...NOT A WHOLE LOT OF CHANGE FROM THURSDAY INTO FRIDAY.
CONTINUED WARM AND ABOVE NORMAL TEMPERATURES WITH A SHALLOW MARINE
LAYER AND LIMITED STRATUS...AS THE RIDGE ALOFT REMAINS OVER
SOUTHERN CALIFORNIA. A SLIGHTLY STRONGER SUNDOWNER IS EXPECTED ON
FRIDAY AND SHOULD APPROACH WIND ADVISORY STRENGTH.
EXTENDED MODELS ARE SHOWING A BROAD TROUGH FORMING OVER THE
NORTHWEST STATES...WHICH WOULD PUSH THE RIDGE TOWARD THE SOUTHEAST.
MODERATELY CONFIDENT OF A COOLING TREND WITH INCREASING ONSHORE FLOW
EARLY NEXT WEEK...BUT THERE IS SOME DISCREPANCIES AS TO HOW MUCH THE
RIDGE MOVES AWAY AND THEREFORE HOW STRONG THAT TREND ENDS UP BEING.
CURRENT FORECAST IS WEIGHTED TOWARD THE BETTER PERFORMING AND COOLER
GFS SOLUTION...BUT DID TEMPER THE COOLING SOME FROM THE PREVIOUS
FORECASTS.
&&
.AVIATION...
26/0600Z
LOW CONFIDENCE IN TAFS FOR KLAX...KLGB...KOXR...KSBA AND KPRB. THERE
IS A 40 PERCENT CHANCE THAT CIGS WILL NOT DEVELOP. ARRIVAL TIMES ARE
ALSO SUSPECT. LOW CONFIDENCE IN EXACT ARRIVAL TIMES FOR KSMX AND
KSBP BUT CIGS SHOULD BE IN PLACE BY 13Z. BETTER CONFIDENCE IN BURN
OFF TIMES.
KLAX...LOW CONFIDENCE IN TAF WITH A 40 PERCENT CHANCE OF NO CIGS AT
ALL. CIGS COULD ARRIVE ANY TIME BETWEEN 10Z AND 13Z. IF CIGS DO
ARRIVE THERE IS A 30 PERCENT CHC OF A 17Z BURN OFF.
KBUR...HIGH CONFIDENCE IN CAVU TAF.
&&
.MARINE...
25/900 PM.
SMALL CRAFT ADVISORY CONDITIONS FOR HAZARDOUS SEAS MAY DEVELOP
TUESDAY NIGHT SOUTH OF POINT CONCEPTION AND PERSIST THROUGH
WEDNESDAY AS SWELLS FROM HURRICANE MARIE MOVE ACROSS THE AREA.
ALSO...SMALL CRAFT CONDITIONS FOR WINDS ARE POSSIBLE EACH AFTERNOON
THURSDAY THROUGH SATURDAY IN THE VICINITY OF POINT CONCEPTION AND
THE NORTHERN CHANNEL ISLANDS WITH GUST TO 30 KNOTS.
&&
.BEACHES...
25/900 PM.
HIGH SURF ADVISORY FOR EXPOSED SOUTH FACING SHORES SOUTH OF POINT
CONCEPTION REMAINS IN EFFECT FROM TUESDAY THROUGH FRIDAY
CONTINUES. HURRICANE MARIE SWELL`S WILL IMPACT THE EXPOSED SOUTH
FACING SHORES NORTH OF POINT CONCEPTION AS WELL AND A HIGH RIP
CURRENT RISK IS EXPECTED. THE CONFIDENCE IS RELATIVELY HIGH AS
MARIE WILL REMAIN A HURRICANE THROUGH TUESDAY EVENING. MARIE IS
EXPECTED TO REMAIN A MAJOR HURRICANE WHILE THE FETCH SHIFTS TO
160-190 DEGREES THROUGH EARLY TUESDAY. AN EXTRATROPICAL STORM IN
THE SOUTHERN HEMISPHERE IS EXPECTED TO STRENGTHEN WITH STORM FORCE
WINDS WITHIN 190-210 DEGREES RELATIVE SOUTHERN CALIFORNIA THIS
WEDNESDAY. THE SWELLS GENERATED ARE EXPECTED TO ARRIVE NEXT WEEK
THURSDAY INTO FRIDAY. PLEASE SEE THE LATEST LAXCFWLOX FOR CURRENT
EVENT DETAILS.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY (SEE LAXCFWLOX).
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
&&
$$
PUBLIC...HALL/KITTELL
AVIATION...ASR
MARINE/BEACHES...HALL
SYNOPSIS...SUKUP
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND JUNCTION CO
337 PM MDT TUE AUG 26 2014
CORRECTED LONG TERM DISCUSSION
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 234 PM MDT TUE AUG 26 2014
CONVECTION STARTING TO GET GOING THIS AFTERNOON THANKS TO THE
CLOSED LOW OVER UTAH...AVAILABLE MOISTURE...UPPER LEVEL TROUGH
ROTATING AROUND LOW AND UPPER LEVEL DYNAMIC SUPPORT. MODEL DIFFERENCES
CONTINUE WITH SOME MODELS BEING MORE AGGRESSIVE THAN OTHERS WITH
HRRR STILL DOING PRETTY WELL PICKING UP ON MOST CONVECTION ACROSS
NM...UT...AZ...AND CO. WHILE SOME SHOWERS AND STORMS ARE MOVING
ACROSS THE CWA...THE HRRR SHOWS THE STRONGER CONVECTION ENTERING
SERN UT THIS EVENING AND THIS LOOKS TO BE PANNING OUT AS A LINE OF
SHOWERS AND STORMS HAS FORMED OVER CENTRAL AND S CENTRAL UTAH AND
IS TRACKING EASTWARD. HIGH SPECIFIC HUMIDITIES LENDING THEMSELVES
TO SOME HEAVY RAINERS SO THE FLASH FLOOD WATCHES WILL REMAIN IN
EFFECT.
RAIN WITH SOME EMBEDDED STORMS WILL CONTINUE OVERNIGHT AS THE
UPPER LEVEL LOW APPROACHES THE FORECAST AREA. THE STORMS AND
SHOWERS OVER THE SAN JUANS WILL SHIFT NORTHWARD AS THE NIGHT
PROGRESSES AND BEST UPPER LEVEL SUPPORT ALSO SHIFTS TO THE
NORTH...STILL ROTATING AROUND THE LOW PRESSURE. SNOW LEVELS ARE
EXPECTED TO DROP NEAR 13K FEET OR SO OVERNIGHT WITH A LIGHT
DUSTING OF SNOW POSSIBLE FOR ELEVATIONS ABOVE THAT. FOR
TOMORROW...MOST PRECIP WILL BE UP NORTH AS THE LOW PRESSURE STARTS
TO FILL AND MOVE OVER UT AND CO. HOWEVER...AS THE LOW MOVES OVER
THE CWA DURING THE DAY UPPER LEVEL DYNAMICS WILL AGAIN PLAY A
FACTOR WITH MORE PRECIP ON TAP FOR MAINLY THE SAN JUANS NORTHWARD.
TEMPERATURES WILL STAY BELOW NORMAL THROUGH THE PERIOD DUE TO
PRECIP AND CLOUDINESS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 234 PM MDT TUE AUG 26 2014
THE UPPER TROUGH DROPS ONTO THE EASTERN PLAINS ON THURSDAY WITH
THE WESTERN MOST ASSOCIATED SHOWERS CLOSE TO THE CONTINENTAL
DIVIDE FAVORING NW-FACING SLOPES. THESE SHOWERS ARE EXPECTED TO
END BY THURSDAY EVENING.
A FLAT RIDGE TRIES TO BUILD IN FROM THE SOUTHWEST ON FRIDAY.
RESIDUAL MOISTURE WILL ALLOW LATE-DAY STORMS TO FIRE MAINLY OVER
THE HIGHER COLORADO TERRAIN. THE RIDGE GETS FLATTENED ON SATURDAY
AS THE NEXT GULF OF ALASKA TROUGH DIGS INTO THE PACIFIC NW.
SATURDAY STILL LOOKS LIKE THE WARMEST DAY OF THE WEEK PERHAPS
HITTING 90 DEGREES ONCE AGAIN IN GRAND JUNCTION AND NEAR 100 IN
THE SE UTAH LOWLANDS.
THE PACIFIC TROUGH WILL PROGRESS THROUGH THE NORTHERN ROCKIES
SUNDAY INTO MONDAY. ITS 100KT JET STREAK SWEEPS THROUGH SOUTHERN
WYOMING. THIS MAY PRODUCE SCATTERED STORMS ACROSS THE NORTHERN
MTNS SUNDAY WITH A FEW STORMS PERSISTING INTO MONDAY. THESE STORMS
WILL BE MOVING TO THE EAST AT 45 MPH SO STRONG WINDS ARE A THREAT.
ELSEWHERE SUNDAY AND MONDAY WILL HAVE BREEZY AFTERNOON WINDS WITH
A SLIGHT COOL DOWN RECOVERING SOMEWHAT ON TUESDAY AS THE TROUGH
WORKS ACROSS THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY NOON)
ISSUED AT 1110 AM MDT TUE AUG 26 2014
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH
WEDNESDAY...WITH COVERAGE INCREASING THROUGHOUT THIS AFTERNOON
AND TONIGHT. EXPECT AREAS OF MVFR CIGS TO DEVELOP TONIGHT AS
RAINFALL INCREASES...ESPECIALLY SOUTH OF INTERSTATE 70. HEAVY
RAIN...SMALL HAIL AND GUSTY OUTFLOW WINDS WILL OCCUR NEAR THE
STRONGER STORMS. ALL SITES WILL SEE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS EXCEEDING 50 PERCENT THROUGH WEDNESDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR COZ018-019-
021>023.
UT...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR UTZ022-027-029.
&&
$$
SHORT TERM...TGR
LONG TERM...JOE
AVIATION...JDC/JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
239 PM MDT TUE AUG 26 2014
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 234 PM MDT TUE AUG 26 2014
CONVECTION STARTING TO GET GOING THIS AFTERNOON THANKS TO THE
CLOSED LOW OVER UTAH...AVAILABLE MOISTURE...UPPER LEVEL TROUGH
ROTATING AROUND LOW AND UPPER LEVEL DYNAMIC SUPPORT. MODEL DIFFERENCES
CONTINUE WITH SOME MODELS BEING MORE AGGRESSIVE THAN OTHERS WITH
HRRR STILL DOING PRETTY WELL PICKING UP ON MOST CONVECTION ACROSS
NM...UT...AZ...AND CO. WHILE SOME SHOWERS AND STORMS ARE MOVING
ACROSS THE CWA...THE HRRR SHOWS THE STRONGER CONVECTION ENTERING
SERN UT THIS EVENING AND THIS LOOKS TO BE PANNING OUT AS A LINE OF
SHOWERS AND STORMS HAS FORMED OVER CENTRAL AND S CENTRAL UTAH AND
IS TRACKING EASTWARD. HIGH SPECIFIC HUMIDITIES LENDING THEMSELVES
TO SOME HEAVY RAINERS SO THE FLASH FLOOD WATCHES WILL REMAIN IN
EFFECT.
RAIN WITH SOME EMBEDDED STORMS WILL CONTINUE OVERNIGHT AS THE
UPPER LEVEL LOW APPROACHES THE FORECAST AREA. THE STORMS AND
SHOWERS OVER THE SAN JUANS WILL SHIFT NORTHWARD AS THE NIGHT
PROGRESSES AND BEST UPPER LEVEL SUPPORT ALSO SHIFTS TO THE
NORTH...STILL ROTATING AROUND THE LOW PRESSURE. SNOW LEVELS ARE
EXPECTED TO DROP NEAR 13K FEET OR SO OVERNIGHT WITH A LIGHT
DUSTING OF SNOW POSSIBLE FOR ELEVATIONS ABOVE THAT. FOR
TOMORROW...MOST PRECIP WILL BE UP NORTH AS THE LOW PRESSURE STARTS
TO FILL AND MOVE OVER UT AND CO. HOWEVER...AS THE LOW MOVES OVER
THE CWA DURING THE DAY UPPER LEVEL DYNAMICS WILL AGAIN PLAY A
FACTOR WITH MORE PRECIP ON TAP FOR MAINLY THE SAN JUANS NORTHWARD.
TEMPERATURES WILL STAY BELOW NORMAL THROUGH THE PERIOD DUE TO
PRECIP AND CLOUDINESS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 234 PM MDT TUE AUG 26 2014
THE UPPER TROUGH DROPS ONTO THE EASTERN PLAINS ON THURSDAY WITH
THE WESTERN MOST ASSOCIATED SHOWERS CLOSE TO THE CONTINENTAL
DIVIDE FAVORING NW-FACING SLOPES. THESE SHOWERS ARE EXPECTED TO
END BY THURSDAY EVENING. THURSDAY AFTERNOON. NORTHWESTERLY FLOW
DEVELOPS BEHIND THE TROUGH WHICH WILL KEEP SCATTERED PRECIP ACROSS
THE CO MTNS. DRIER AIR SPREADS ACROSS ERN UT INTO FAR WRN CO THU.
A FLAT RIDGE TRIES TO BUILD IN FROM THE SOUTHWEST ON FRIDAY.
RESIDUAL MOISTURE WILL ALLOW LATE-DAY STORMS TO FIRE MAINLY OVER
THE HIGHER COLORADO TERRAIN. THE RIDGE GETS FLATTENED ON SATURDAY
AS THE NEXT GULF OF ALASKA TROUGH DIGS INTO THE PACIFIC NW.
SATURDAY STILL LOOKS LIKE THE WARMEST DAY OF THE WEEK PERHAPS
HITTING 90 DEGREES ONCE AGAIN IN GRAND JUNCTION AND NEAR 100 IN
THE SE UTAH LOWLANDS.
THE PACIFIC TROUGH WILL PROGRESS THROUGH THE NORTHERN ROCKIES
SUNDAY INTO MONDAY. ITS 100KT JET STREAK SWEEPS THROUGH SOUTHERN
WYOMING. THIS MAY PRODUCE SCATTERED STORMS ACROSS THE NORTHERN
MTNS SUNDAY WITH A FEW STORMS PERSISTING INTO MONDAY. THESE STORMS
WILL BE MOVING TO THE EAST AT 45 MPH SO STRONG WINDS ARE A THREAT.
ELSEWHERE SUNDAY AND MONDAY WILL HAVE BREEZY AFTERNOON WINDS WITH
A SLIGHT COOL DOWN RECOVERING SOMEWHAT ON TUESDAY AS THE TROUGH
WORKS ACROSS THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY NOON)
ISSUED AT 1110 AM MDT TUE AUG 26 2014
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH
WEDNESDAY...WITH COVERAGE INCREASING THROUGHOUT THIS AFTERNOON
AND TONIGHT. EXPECT AREAS OF MVFR CIGS TO DEVELOP TONIGHT AS
RAINFALL INCREASES...ESPECIALLY SOUTH OF INTERSTATE 70. HEAVY
RAIN...SMALL HAIL AND GUSTY OUTFLOW WINDS WILL OCCUR NEAR THE
STRONGER STORMS. ALL SITES WILL SEE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS EXCEEDING 50 PERCENT THROUGH WEDNESDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR COZ018-019-
021>023.
UT...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR UTZ022-027-029.
&&
$$
SHORT TERM...TGR
LONG TERM...JOE
AVIATION...JDC/JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1200 PM MDT TUE AUG 26 2014
.UPDATE...
ISSUED AT 1152 AM MDT TUE AUG 26 2014
AFTER COLLABORATION WITH SLC...THINK IT BEST TO GO WITH FLASH
FLOOD WATCH FOR SERN UT THROUGH MIDNIGHT TONIGHT. LATEST RADAR
RETURNS SHOW MORE CELLS STARTING TO FIRE OVER WATCH AREA AND
EXPECTING THIS TREND TO CONTINUE. THUNDERSTORMS AND SHOWERS WILL
ALSO BECOME MORE INTENSE AS THE DAY PROGRESSES WITH HEAVY RAIN
LIKELY UNDER THE STRONGEST STORMS.
UPDATE ISSUED AT 1121 AM MDT TUE AUG 26 2014
A LINE OF SHOWERS AND STORMS STRETCHES FROM STEAMBOAT SPRINGS SW
DOWN TO THE GRAND VALLEY AND THEN CANYONLANDS IN RESPONSE TO UPPER
LEVEL DIVERGENCE AND JET STREAK ALOFT. MODELS NOT INTIALIZING TOO
WELL THIS MORNING WITH EXCEPTION OF HRRR THAT IS PICKING UP ON
SOME FEATURES ESPECIALLY PRECIP OVER NM AND AZ. IF HRRR PULLS
THROUGH...PRECIP WILL INCREASE TOWARDS THE EVENING HOURS OVER SE UT
BEFORE OVERSPREADING THE REST OF THE CWA OVERNIGHT. IN CONTRAST...NAM12
SHOWS COVERAGE INCREASING FROM NOON ONWARDS WITH HIGHER TERRAIN
FAVORED AS SHORTWAVE MOVES THROUGH. SOME CONCERNS THIS MORNING ARE
CLOUD COVER WHICH MAY INHIBIT CONVECTION THOUGH BREAKS IN CLOUDS
ARE OCCURRING OVER SWRN CO WHICH SHOULD ALLOW CONVECTION TO FIRE
AS THE DAY PROGRESSES. OTHER CONCERN IS IF PRECIP BECOMES MORE
STRATIFORM IN NATURE LOWERING FLASH FLOODING CHANCES. CONFIDENCE
NOT THAT GREAT IN ANY MODEL SOLN SO WILL CONTINUE TO MONITOR
EVOLUTION OF LOW PRESSURE AND ACCOMPANYING PRECIP AND FLASH FLOOD
CHANCES.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 346 AM MDT TUE AUG 26 2014
TRANSITION DAY TODAY AS WE START TO SEE THE INFLUENCE OF STRONG
FALL LIKE SYSTEM DIGGING INTO THE GREAT BASIN. MOISTURE WRAPPING
AROUND THE SOUTHERN AND EASTERN FLANKS OF THE STRENGTHENING LOW
PRESSURE SYSTEM WILL BRING WIDESPREAD SHOWERS AND THUNDERSTORMS TO
MUCH OF WESTERN COLORADO AND EASTERN UTAH OVER THE NEXT FEW DAYS.
MODELS HAVE BACKED OFF A BIT ON POTENTIAL QPF VALUES THIS
AFTERNOON...BUT INCREASING DYNAMICS ASSOCIATED WITH THE
APPROACHING LOW AND AVAILABLE MOISTURE CLIMBING BACK TO AN INCH
ACROSS THE FOUR CORNERS WILL RESULT IN LOCALLY HEAVY RAINFALL BY
LATE THIS AFTERNOON...MAINLY OVER THE SAN JUANS AND ADJACENT
SOUTHERN VALLEYS. FOUR CORNERS REGION BEING HIGHLIGHT BY WPC FOR
EXCESSIVE RAINFALL OVER THE NEXT 24 TO 36 HOURS AND CURRENT FLASH
FLOOD WATCH REMAINS ON TRACK. BULK OF HEAVIER RAIN WILL BE HOLDING
OFF UNTIL LATE IN THE DAY BASED ON LATEST 06Z MODELS...SO HAVE
TWEAKED DAYTIME POPS AND QPF DOWN A BIT AND NUDGED OVERNIGHT
VALUES UP A BIT. HAVE ALSO EXTENDED THE FLASH FLOOD WATCH THROUGH
9 AM WEDNESDAY MORNING AS BEST FORCING ASSOCIATED WITH THE LOW
MOVING IN OVERNIGHT. TEMPS WILL BE DOWN A FEW DEGREES TODAY WITH
INCREASED CLOUD COVER AND LOW LEVEL MOISTURE.
THE UPPER LOW SWINGS INTO WRN UT THIS EVENING. SHOWERS AND SCATTERED
THUNDERSTORMS CONTINUE IN DIFLUENT FLOW AHEAD OF THE LOW.
INSTABILITY NOT GREAT PER MODEL LIFTED INDEX AND CAPE...BUT MOISTURE
IS AMPLE ESPECIALLY ACROSS THE SOUTH WHERE LIFT SHOULD BE AIDED BY
SOUTHERLY UPSLOPE FLOW INTO THE SAN JUANS.
THE UPPER LOW CENTER IS FORECAST TO BE OVER NE UT BY NOON WED AND
ACROSS WRN CO WED EVENING. LARGE-SCALE ASCENT ASSOCIATED WITH THE
LOW CENTER PLUS LOWER LEVEL MOISTURE CONVERGENCE AS THE MOISTURE
STREAM WRAPS INTO THE LOW WILL KEEP RAIN/RAIN SHOWERS WITH EMBEDDED
THUNDERSTORMS A DECENT BET FOR MUCH OF THE CENTRAL AND NORTH WED.
UPPER JET CUTS ACROSS THE 4 CORNERS BY MIDDAY ENTRAINING SOMEWHAT
DRIER AIR ALOFT. RAIN COVERAGE LOOKS LESS ACROSS THE SOUTH BUT
STORMS COULD BE STRONGER WITH MODEST CAPE/INSTABILITY...SOME DRYING
ALOFT AND BETTER VERTICAL SHEAR WITH THE JET PASSING. NUDGED THE WED
POPS UPWARD TONIGHT AND WED. TEMPS REMAIN ON THE COOL SIDE OF
NORMAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 AM MDT TUE AUG 26 2014
THE UPPER TROUGH MOVES INTO ERN UT BY THURSDAY AFTERNOON.
NORTHWESTERLY FLOW DEVELOPS BEHIND THE TROUGH WHICH WILL KEEP
SCATTERED PRECIP ACROSS THE CO MTNS. DRIER AIR SPREADS ACROSS ERN UT
INTO FAR WRN CO THU.
FLAT RIDGING FRIDAY GIVES WAY TO BRIEF PERIOD OF ZONAL FLOW
SATURDAY AND EARLY SUNDAY...BEFORE HEIGHTS DROP ONCE AGAIN AS
ANOTHER PACIFIC SYSTEM SLIDES ACROSS WYOMING. THIS WAVE CLIPS THE
NORTHERN HALF OF THE FORECAST AREA...BRINGING A CHANCE FOR SHOWERS
AND THUNDERSTORMS LATE SUNDAY AND SUNDAY NIGHT WITH A FEW SHOWERS
LINGERING INTO THE DAY ON MONDAY. TEMPS WILL MODERATE A BIT FRIDAY
AND SATURDAY...BEFORE DROPPING BACK BELOW SEASONAL NORMS AS WE
MOVE INTO THE NEW WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY NOON)
ISSUED AT 1110 AM MDT TUE AUG 26 2014
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH
WEDNESDAY...WITH COVERAGE INCREASING THROUGHOUT THIS AFTERNOON
AND TONIGHT. EXPECT AREAS OF MVFR CIGS TO DEVELOP TONIGHT AS
RAINFALL INCREASES...ESPECIALLY SOUTH OF INTERSTATE 70. HEAVY
RAIN...SMALL HAIL AND GUSTY OUTFLOW WINDS WILL OCCUR NEAR THE
STRONGER STORMS. ALL SITES WILL SEE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS EXCEEDING 50 PERCENT THROUGH WEDNESDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR COZ018-019-
021>023.
UT...FLASH FLOOD WATCH THROUGH THIS EVENING FOR UTZ022-027-029.
&&
$$
UPDATE...TGR
SHORT TERM...JDC/JAD
LONG TERM...JAD/JDC
AVIATION...JDC/JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1131 AM MDT TUE AUG 26 2014
.UPDATE...
ISSUED AT 1121 AM MDT TUE AUG 26 2014
A LINE OF SHOWERS AND STORMS STRETCHES FROM STEAMBOAT SPRINGS SW
DOWN TO THE GRAND VALLEY AND THEN CANYONLANDS IN RESPONSE TO UPPER
LEVEL DIVERGENCE AND JET STREAK ALOFT. MODELS NOT INTIALIZING TOO
WELL THIS MORNING WITH EXCEPTION OF HRRR THAT IS PICKING UP ON
SOME FEATURES ESPECIALLY PRECIP OVER NM AND AZ. IF HRRR PULLS
THROUGH...PRECIP WILL INCREASE TOWARDS THE EVENING HOURS OVER SE UT
BEFORE OVERSPREADING THE REST OF THE CWA OVERNIGHT. IN CONTRAST...NAM12
SHOWS COVERAGE INCREASING FROM NOON ONWARDS WITH HIGHER TERRAIN
FAVORED AS SHORTWAVE MOVES THROUGH. SOME CONCERNS THIS MORNING ARE
CLOUD COVER WHICH MAY INHIBIT CONVECTION THOUGH BREAKS IN CLOUDS
ARE OCCURRING OVER SWRN CO WHICH SHOULD ALLOW CONVECTION TO FIRE
AS THE DAY PROGRESSES. OTHER CONCERN IS IF PRECIP BECOMES MORE
STRATIFORM IN NATURE LOWERING FLASH FLOODING CHANCES. CONFIDENCE
NOT THAT GREAT IN ANY MODEL SOLN SO WILL CONTINUE TO MONITOR
EVOLUTION OF LOW PRESSURE AND ACCOMPANYING PRECIP AND FLASH FLOOD
CHANCES.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 346 AM MDT TUE AUG 26 2014
TRANSITION DAY TODAY AS WE START TO SEE THE INFLUENCE OF STRONG
FALL LIKE SYSTEM DIGGING INTO THE GREAT BASIN. MOISTURE WRAPPING
AROUND THE SOUTHERN AND EASTERN FLANKS OF THE STRENGTHENING LOW
PRESSURE SYSTEM WILL BRING WIDESPREAD SHOWERS AND THUNDERSTORMS TO
MUCH OF WESTERN COLORADO AND EASTERN UTAH OVER THE NEXT FEW DAYS.
MODELS HAVE BACKED OFF A BIT ON POTENTIAL QPF VALUES THIS
AFTERNOON...BUT INCREASING DYNAMICS ASSOCIATED WITH THE
APPROACHING LOW AND AVAILABLE MOISTURE CLIMBING BACK TO AN INCH
ACROSS THE FOUR CORNERS WILL RESULT IN LOCALLY HEAVY RAINFALL BY
LATE THIS AFTERNOON...MAINLY OVER THE SAN JUANS AND ADJACENT
SOUTHERN VALLEYS. FOUR CORNERS REGION BEING HIGHLIGHT BY WPC FOR
EXCESSIVE RAINFALL OVER THE NEXT 24 TO 36 HOURS AND CURRENT FLASH
FLOOD WATCH REMAINS ON TRACK. BULK OF HEAVIER RAIN WILL BE HOLDING
OFF UNTIL LATE IN THE DAY BASED ON LATEST 06Z MODELS...SO HAVE
TWEAKED DAYTIME POPS AND QPF DOWN A BIT AND NUDGED OVERNIGHT
VALUES UP A BIT. HAVE ALSO EXTENDED THE FLASH FLOOD WATCH THROUGH
9 AM WEDNESDAY MORNING AS BEST FORCING ASSOCIATED WITH THE LOW
MOVING IN OVERNIGHT. TEMPS WILL BE DOWN A FEW DEGREES TODAY WITH
INCREASED CLOUD COVER AND LOW LEVEL MOISTURE.
THE UPPER LOW SWINGS INTO WRN UT THIS EVENING. SHOWERS AND SCATTERED
THUNDERSTORMS CONTINUE IN DIFLUENT FLOW AHEAD OF THE LOW.
INSTABILITY NOT GREAT PER MODEL LIFTED INDEX AND CAPE...BUT MOISTURE
IS AMPLE ESPECIALLY ACROSS THE SOUTH WHERE LIFT SHOULD BE AIDED BY
SOUTHERLY UPSLOPE FLOW INTO THE SAN JUANS.
THE UPPER LOW CENTER IS FORECAST TO BE OVER NE UT BY NOON WED AND
ACROSS WRN CO WED EVENING. LARGE-SCALE ASCENT ASSOCIATED WITH THE
LOW CENTER PLUS LOWER LEVEL MOISTURE CONVERGENCE AS THE MOISTURE
STREAM WRAPS INTO THE LOW WILL KEEP RAIN/RAIN SHOWERS WITH EMBEDDED
THUNDERSTORMS A DECENT BET FOR MUCH OF THE CENTRAL AND NORTH WED.
UPPER JET CUTS ACROSS THE 4 CORNERS BY MIDDAY ENTRAINING SOMEWHAT
DRIER AIR ALOFT. RAIN COVERAGE LOOKS LESS ACROSS THE SOUTH BUT
STORMS COULD BE STRONGER WITH MODEST CAPE/INSTABILITY...SOME DRYING
ALOFT AND BETTER VERTICAL SHEAR WITH THE JET PASSING. NUDGED THE WED
POPS UPWARD TONIGHT AND WED. TEMPS REMAIN ON THE COOL SIDE OF
NORMAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 346 AM MDT TUE AUG 26 2014
THE UPPER TROUGH MOVES INTO ERN UT BY THURSDAY AFTERNOON.
NORTHWESTERLY FLOW DEVELOPS BEHIND THE TROUGH WHICH WILL KEEP
SCATTERED PRECIP ACROSS THE CO MTNS. DRIER AIR SPREADS ACROSS ERN UT
INTO FAR WRN CO THU.
FLAT RIDGING FRIDAY GIVES WAY TO BRIEF PERIOD OF ZONAL FLOW
SATURDAY AND EARLY SUNDAY...BEFORE HEIGHTS DROP ONCE AGAIN AS
ANOTHER PACIFIC SYSTEM SLIDES ACROSS WYOMING. THIS WAVE CLIPS THE
NORTHERN HALF OF THE FORECAST AREA...BRINGING A CHANCE FOR SHOWERS
AND THUNDERSTORMS LATE SUNDAY AND SUNDAY NIGHT WITH A FEW SHOWERS
LINGERING INTO THE DAY ON MONDAY. TEMPS WILL MODERATE A BIT FRIDAY
AND SATURDAY...BEFORE DROPPING BACK BELOW SEASONAL NORMS AS WE
MOVE INTO THE NEW WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY NOON)
ISSUED AT 1110 AM MDT TUE AUG 26 2014
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH
WEDNESDAY...WITH COVERAGE INCREASING THROUGHOUT THIS AFTERNOON
AND TONIGHT. EXPECT AREAS OF MVFR CIGS TO DEVELOP TONIGHT AS
RAINFALL INCREASES...ESPECIALLY SOUTH OF INTERSTATE 70. HEAVY
RAIN...SMALL HAIL AND GUSTY OUTFLOW WINDS WILL OCCUR NEAR THE
STRONGER STORMS. ALL SITES WILL SEE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS EXCEEDING 50 PERCENT THROUGH WEDNESDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR COZ018-019-
021>023.
UT...NONE.
&&
$$
UPDATE...TGR
SHORT TERM...JDC/JAD
LONG TERM...JAD/JDC
AVIATION...JDC/JOE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1148 PM MDT MON AUG 25 2014
.UPDATE...
ISSUED AT 1015 PM MDT MON AUG 25 2014
UPDATED TO EXPIRE THE TSTORM WATCH. ANY ACTIVITY TONIGHT SHOULD
STAY SUB SVR.
ALSO ISSUED A FLASH FLOOD WATCH FOR TOMORROW. MODEL CONSENSUS
AND CURRENT OBS INDICATE LOTS OF SUBTROPICAL MOISTURE HEADED
OUR WAY. DEWPOINTS WILL REMAIN IN THE 50S AND 60S. PREC H20 IN
THE 1-1.5 INCH RANGE. DEEP SRLY FLOW IN PLACE. LOOKS PRETTY
CONDUCIVE TO LOCALIZED FLASH FLOODING. STORMS SHOULD SPREAD FROM
THE SW MTS EARLY TO THE ERN MTS AND I-25 BY AFTERNOON...THEN ON TO
THE PLAINS BY LATE AFTERNOON OR EVE. ROSE
UPDATE ISSUED AT 753 PM MDT MON AUG 25 2014
UPDATED TO CLEAR PUEBLO CTY FROM THE WATCH...AND ADJUST POPS PER
RADAR AND MODEL TRENDS. ROSE
UPDATE ISSUED AT 424 PM MDT MON AUG 25 2014
UPDATED FOR INCLUSION OF SVR TSTORM WATCH FOR EL PASO
CROWLEY AND KIOWA COUNTIES. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
CURRENTLY...COLD FRONT HAS BECOME STATIONARY NEAR THE NM BORDER
THIS AFTERNOON...AND WILL LIKELY DRIFT BACK NORTHWARD TOWARD THE
ARKANSAS RIVER BY 00Z. CONVECTION OVER THE MOUNTAINS AND ALONG THE
RATON MESA HAS BEEN RELATIVELY WEAK SO FAR AS STORMS HAVE YET TO
TAP DEEPER INSTABILITY NEAR THE KS BORDER AND FARTHER NORTH NEAR THE
PALMER DIVIDE. WITH COOL AIR SLIGHTLY DEEPER THAN EXPECTED...APPEARS
HIGH TEMPS WILL END UP JUST SHY OF FORECAST READINGS.
TONIGHT...MESOSCALE MODELS CONTINUE TO POINT TO AREAS ALONG AND
NORTH OF THE PALMER DIVIDE HAVING THE BEST CHANCE FOR STRONG/SEVERE
CONVECTION...THOUGH LATEST HRRR HINTS AT SOME SOME BRIEF STRONGER
STORMS OVER THE FAR EASTERN PLAINS...AS FRONTAL BOUNDARY RETREATING
NORTHWARD PROVIDES SOME ENHANCED CONVERGENCE. WEAK SHORT WAVE...OVER
WRN CO CURRENTLY...WILL ALSO PROVIDE SOME UPWARD MOTION AS IT
CROSSES THE AREA THIS EVENING. BY MIDNIGHT...SUSPECT CONVECTION WILL
SHIFT NORTHEAST AND COALESCE INTO AN MCS OVER NWRN KS/SRN NEB...WITH
FAIRLY LARGE COLD POOL GIVING SURFACE FRONT A RENEWED SHOVE
SOUTHWARD THROUGH THE EASTERN PLAINS. WITH A GRADUAL INCREASE IN MID
LEVEL MOISTURE THROUGH THE NIGHT AND BOUNDARY MOVING BACK
SOUTHWARD...WILL ONLY GRADUALLY TAPER OFF POPS THROUGH THE
EVENING...WITH AT LEAST SOME ISOLATED TSRA POSSIBLE PAST MIDNIGHT.
TUESDAY.. UPPER LOW WILL CONTINUE TO SLOWLY PUSH EASTWARD THROUGH
THE GREAT BASIN...WITH STRENGTHENING S-SW FLOW AHEAD OF THE SYSTEM
PUSHING AN INCREASING AMOUNT OF TROPICAL MOISTURE NORTHWARD INTO
COLORADO. SURFACE FRONT WILL LIKELY STAY SOUTH OF THE ARKANSAS RIVER
THROUGH THE DAY...WITH E-SE FLOW PUSHING 55F-60F DEWPOINTS WESTWARD
TOWARD THE I-25 CORRIDOR. WITH MOISTURE PLENTIFUL...EXPECT EARLY
INITIATION OF CONVECTION WITH STORMS FIRING OVER THE MOUNTAINS
BEFORE 18Z AND SPREADING QUICKLY TO LOWER ELEVATIONS BY 21Z. MAIN
THREAT TOMORROW OVER ALL AREAS WILL BE HEAVY RAINFALL...THOUGH WITH
CAPES OVER 1000 J/KG AND 0-6KM SHEAR OF 30-40 KTS...A SEVERE STORM
OR TWO IS POSSIBLE ON THE PLAINS MAINLY ALONG AND NORTH OF THE
ARKANSAS RIVER. ALL IN ALL...IT LOOKS LIKE A VERY WET DAY OVER MUCH
OF SOUTHERN COLORADO...AND WITH CLOUDS AND PRECIP FAIRLY QUICK TO
DEVELOP...MAX TEMPS SHOULD COOL AT LEAST A FEW DEGF VERSUS MON
READINGS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
TUESDAY NIGHT THROUGH FRIDAY...LATEST RUNS OF THE NAM...GFS AND EC
MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PROGRESSION OF THE UPPER
TROUGH ACROSS THE REGION THROUGH THIS WEEK. TUE EVENING THE TROUGH
WILL BE POISED OVER NV AND UT...CONTINUING TO DRAW A STRONG MOISTURE
PLUME UP ACROSS THE 4 CORNERS AND INTO CO. THE TROUGH STEADILY
MARCHES TO THE EAST ACROSS COLORADO THROUGH WED AND THU...WITH THE
TROUGH AXIS FINALLY REACHING THE OK AND TX PANHANDLES BY FRI
MORNING. A GOOD AMOUNT OF MOISTURE...COUPLED WITH AVAILABLE DYNAMICS
AND A COLD FRONT WED EVE WILL PROVIDE FOR WIDESPREAD CONVECTION
CHANCES THROUGH THE PERIOD...WITH PCPN FINALLY TAPERING OFF FRI
MORNING. LOOK FOR SCATTERED POPS FOR MUCH OF THE AREA TUE EVE AND
AGAIN WED EVE THROUGH THU...WITH PCPN LIKELY OVER THE MTS. TEMPS ARE
EXPECTED TO REMAIN COOLER THROUGH FRI WITH MAX TEMPS IN THE UPPER
70S AND 80S FOR THE PLAINS...AND 60S AND 70S FOR THE HIGH VALLEYS.
SATURDAY THROUGH MONDAY...AS THE TROUGH EXITS TO THE EAST...A RIDGE
OF HIGH PRESSURE BUILDS OVER THE SW US. THIS WILL HELP A DRYING AND
WARMING TREND TO TAKE HOLD OVER THE WEEKEND AND INTO THE FIRST PART
OF THE NEXT WORK WEEK. PCPN CHANCES ARE FORECAST TO BE RESTRICTED TO
JUST ISOLATED DIURNAL ACTIVITY OVER THE HIGHER TERRAIN...AND TEMPS
WILL CLIMB BACK UP INTO THE 80S NEARING 90 F FOR THE PLAINS...AND
INTO THE 80S FOR THE HIGH VALLEYS. MOORE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1137 PM MDT MON AUG 25 2014
MAIN AVN CONCERN IS THE POTENTIAL FOR SIGNIFICANT IMPACTS
FOR THE TERMINALS ON TUESDAY...ESPECIALLY AFTER 20Z. A STORM
SYSTEM MOVING INTO EASTERN NV/W UT TUE AFTERNOON WILL REINFORCE
A STRONG MONSOONAL FLOW OF MOISTURE INTO SE CO. THIS WILL BRING
THE POTENTIAL FOR NUMEROUS SHOWERS AND STORMS...SOME OF WHICH
COULD BE ON THE STRONG SIDE WITH HEAVY RAIN AND HAIL. VIS COULD
BE REDUCED TO IFR OR LOWER AT TIMES IN THE STRONGER STORMS
TUE AFTERNOON AND EVENING. STORMS WILL MOVE EWD TO THE PLAINS BY
LATE TUE EVE...BUT WILL LEAVE LINGERING POCKETS OF MVFR TO
POTENTIALLY IFR CIGS THROUGH WED MORNING. THIS STORM SYSTEM
WILL LINGER THROUGH THURSDAY...AND WILL BRING THE THREAT OF MORE
HEAVY RAIN AND STORMS BOTH LATE WEDNESDAY AND AGAIN THURSDAY.
FZG LEVELS WILL LOWER TO ABOUT 6K FT AGL BY THU. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY
NIGHT FOR COZ066>068-072>089-093>099.
&&
$$
UPDATE...ROSE
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1020 PM MDT MON AUG 25 2014
.UPDATE...
ISSUED AT 1015 PM MDT MON AUG 25 2014
UPDATED TO EXPIRE THE TSTORM WATCH. ANY ACTIVITY TONIGHT SHOULD
STAY SUB SVR.
ALSO ISSUED A FLASH FLOOD WATCH FOR TOMORROW. MODEL CONSENSUS
AND CURRENT OBS INDICATE LOTS OF SUBTROPICAL MOISTURE HEADED
OUR WAY. DEWPOINTS WILL REMAIN IN THE 50S AND 60S. PREC H20 IN
THE 1-1.5 INCH RANGE. DEEP SRLY FLOW IN PLACE. LOOKS PRETTY
CONDUCIVE TO LOCALIZED FLASH FLOODING. STORMS SHOULD SPREAD FROM
THE SW MTS EARLY TO THE ERN MTS AND I-25 BY AFTERNOON...THEN ON TO
THE PLAINS BY LATE AFTERNOON OR EVE. ROSE
UPDATE ISSUED AT 753 PM MDT MON AUG 25 2014
UPDATED TO CLEAR PUEBLO CTY FROM THE WATCH...AND ADJUST POPS PER
RADAR AND MODEL TRENDS. ROSE
UPDATE ISSUED AT 424 PM MDT MON AUG 25 2014
UPDATED FOR INCLUSION OF SVR TSTORM WATCH FOR EL PASO
CROWLEY AND KIOWA COUNTIES. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
CURRENTLY...COLD FRONT HAS BECOME STATIONARY NEAR THE NM BORDER
THIS AFTERNOON...AND WILL LIKELY DRIFT BACK NORTHWARD TOWARD THE
ARKANSAS RIVER BY 00Z. CONVECTION OVER THE MOUNTAINS AND ALONG THE
RATON MESA HAS BEEN RELATIVELY WEAK SO FAR AS STORMS HAVE YET TO
TAP DEEPER INSTABILITY NEAR THE KS BORDER AND FARTHER NORTH NEAR THE
PALMER DIVIDE. WITH COOL AIR SLIGHTLY DEEPER THAN EXPECTED...APPEARS
HIGH TEMPS WILL END UP JUST SHY OF FORECAST READINGS.
TONIGHT...MESOSCALE MODELS CONTINUE TO POINT TO AREAS ALONG AND
NORTH OF THE PALMER DIVIDE HAVING THE BEST CHANCE FOR STRONG/SEVERE
CONVECTION...THOUGH LATEST HRRR HINTS AT SOME SOME BRIEF STRONGER
STORMS OVER THE FAR EASTERN PLAINS...AS FRONTAL BOUNDARY RETREATING
NORTHWARD PROVIDES SOME ENHANCED CONVERGENCE. WEAK SHORT WAVE...OVER
WRN CO CURRENTLY...WILL ALSO PROVIDE SOME UPWARD MOTION AS IT
CROSSES THE AREA THIS EVENING. BY MIDNIGHT...SUSPECT CONVECTION WILL
SHIFT NORTHEAST AND COALESCE INTO AN MCS OVER NWRN KS/SRN NEB...WITH
FAIRLY LARGE COLD POOL GIVING SURFACE FRONT A RENEWED SHOVE
SOUTHWARD THROUGH THE EASTERN PLAINS. WITH A GRADUAL INCREASE IN MID
LEVEL MOISTURE THROUGH THE NIGHT AND BOUNDARY MOVING BACK
SOUTHWARD...WILL ONLY GRADUALLY TAPER OFF POPS THROUGH THE
EVENING...WITH AT LEAST SOME ISOLATED TSRA POSSIBLE PAST MIDNIGHT.
TUESDAY.. UPPER LOW WILL CONTINUE TO SLOWLY PUSH EASTWARD THROUGH
THE GREAT BASIN...WITH STRENGTHENING S-SW FLOW AHEAD OF THE SYSTEM
PUSHING AN INCREASING AMOUNT OF TROPICAL MOISTURE NORTHWARD INTO
COLORADO. SURFACE FRONT WILL LIKELY STAY SOUTH OF THE ARKANSAS RIVER
THROUGH THE DAY...WITH E-SE FLOW PUSHING 55F-60F DEWPOINTS WESTWARD
TOWARD THE I-25 CORRIDOR. WITH MOISTURE PLENTIFUL...EXPECT EARLY
INITIATION OF CONVECTION WITH STORMS FIRING OVER THE MOUNTAINS
BEFORE 18Z AND SPREADING QUICKLY TO LOWER ELEVATIONS BY 21Z. MAIN
THREAT TOMORROW OVER ALL AREAS WILL BE HEAVY RAINFALL...THOUGH WITH
CAPES OVER 1000 J/KG AND 0-6KM SHEAR OF 30-40 KTS...A SEVERE STORM
OR TWO IS POSSIBLE ON THE PLAINS MAINLY ALONG AND NORTH OF THE
ARKANSAS RIVER. ALL IN ALL...IT LOOKS LIKE A VERY WET DAY OVER MUCH
OF SOUTHERN COLORADO...AND WITH CLOUDS AND PRECIP FAIRLY QUICK TO
DEVELOP...MAX TEMPS SHOULD COOL AT LEAST A FEW DEGF VERSUS MON
READINGS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
TUESDAY NIGHT THROUGH FRIDAY...LATEST RUNS OF THE NAM...GFS AND EC
MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PROGRESSION OF THE UPPER
TROUGH ACROSS THE REGION THROUGH THIS WEEK. TUE EVENING THE TROUGH
WILL BE POISED OVER NV AND UT...CONTINUING TO DRAW A STRONG MOISTURE
PLUME UP ACROSS THE 4 CORNERS AND INTO CO. THE TROUGH STEADILY
MARCHES TO THE EAST ACROSS COLORADO THROUGH WED AND THU...WITH THE
TROUGH AXIS FINALLY REACHING THE OK AND TX PANHANDLES BY FRI
MORNING. A GOOD AMOUNT OF MOISTURE...COUPLED WITH AVAILABLE DYNAMICS
AND A COLD FRONT WED EVE WILL PROVIDE FOR WIDESPREAD CONVECTION
CHANCES THROUGH THE PERIOD...WITH PCPN FINALLY TAPERING OFF FRI
MORNING. LOOK FOR SCATTERED POPS FOR MUCH OF THE AREA TUE EVE AND
AGAIN WED EVE THROUGH THU...WITH PCPN LIKELY OVER THE MTS. TEMPS ARE
EXPECTED TO REMAIN COOLER THROUGH FRI WITH MAX TEMPS IN THE UPPER
70S AND 80S FOR THE PLAINS...AND 60S AND 70S FOR THE HIGH VALLEYS.
SATURDAY THROUGH MONDAY...AS THE TROUGH EXITS TO THE EAST...A RIDGE
OF HIGH PRESSURE BUILDS OVER THE SW US. THIS WILL HELP A DRYING AND
WARMING TREND TO TAKE HOLD OVER THE WEEKEND AND INTO THE FIRST PART
OF THE NEXT WORK WEEK. PCPN CHANCES ARE FORECAST TO BE RESTRICTED TO
JUST ISOLATED DIURNAL ACTIVITY OVER THE HIGHER TERRAIN...AND TEMPS
WILL CLIMB BACK UP INTO THE 80S NEARING 90 F FOR THE PLAINS...AND
INTO THE 80S FOR THE HIGH VALLEYS. MOORE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 305 PM MDT MON AUG 25 2014
TSRA DEVELOPING OVER THE MOUNTAINS WILL CONTINUE TO SPREAD TO LOWER
ELEVATIONS THIS AFTERNOON...WITH STORMS NEAR KCOS AND KPUB IN THE
22Z-02Z PERIOD...AND AROUND KALS 22Z-01Z. WITH MORE MOISTURE
AVAILABLE TODAY...EXPECT LOWER CLOUD BASES AND RESTRICTED VISIBILITY
UNDER THE STRONGEST STORMS...AND LOCAL MVFR/BRIEF IFR CONDITIONS
WILL BE POSSIBLE. STORMS WILL GRADUALLY SHIFT INTO NORTHEAST
COLORADO THIS EVENING AND OVERNIGHT...WITH A COLD FRONT AND SHIFT TO
NORTHEAST WINDS PUSHING SOUTHWARD ACROSS THE PLAINS AFTER 00Z. MAY
SEE SOME IFR STRATUS ALONG THE PALMER DIVIDE BY 12Z TUE...BUT
HAVEN`T INCLUDED LOWER CLOUDS IN KCOS TAF AS NORTH WIND MAY KEEP
CLOUDS JUST NORTH OF THE AIRPORT. ON TUE...EXPECT WIDESPREAD TSRA
ALL AREAS...WITH EARLY STORM INITIATION OVER THE MOUNTAINS BY 18Z.
BY MID TO LATE AFTERNOON...MTS WILL BE OBSCURED AND MVFR CONDITIONS
WITH THUNDERSTORMS WILL BE POSSIBLE AT ALL TAF SITES.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY
NIGHT FOR COZ066>068-072>089-093>099.
&&
$$
UPDATE...ROSE
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
722 PM EDT WED AUG 27 2014
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS AHEAD OF A COLD FRONT WILL CONTINUE TO
SWEEP ACROSS SOUTHERN NEW ENGLAND OVERNIGHT. DRIER AND LESS HUMID
AIR OVERSPREADS THE REGION THURSDAY AND FRIDAY YIELDING MILD DAYS
AND COOL NIGHTS. HURRICANE CRISTOBAL WILL PASS WELL OFFSHORE LATE
TONIGHT INTO THURSDAY BRINGING DANGEROUS SURF AND RIP CURRENTS TO
SOUTH FACING OCEAN BEACHES OF RI AND MA. PLEASANT WEATHER LINGERS
INTO SATURDAY...THEN A FRONT WILL SWEEP ACROSS NEW ENGLAND LATE
SUNDAY INTO MONDAY BRINGING UNSETTLED CONDITIONS.
&&
.NEAR TERM /THROUGH THURSDAY/...
730 PM UPDATE...
LINE OF SHOWERS / THUNDERSTORMS DIMINISHING AS IT PROGRESSES SE
ENCOUNTERING A LESS UNSTABLE AIRMASS. WITHIN AN ENVIRONMENT OF
LESS FAVORABLE SHEAR...MAIN THREATS WITH ANY STORMS WILL BE HEAVY
RAIN /PWATS AROUND 1.50-1.75 INCHES/ AND GUSTY WINDS SUBSEQUENT AS
NOTED BY THE PREVIOUS FORECASTER BY INVERTED-V SOUNDINGS. FEEL
SUCH THREATS WILL ONLY LAST INTO THE EARLY EVENING. THEREAFTER A
LINE OF SHOWERS IS EXPECTED TO BE MAINTAINED BY THE MID-LEVEL
TROUGH AND ATTENDANT SYNOPTIC SCALE FORCING OF AVAILABLE MOISTURE
CONVERGENT ALONG AND AHEAD OF THE PARENT FRONTAL BOUNDARY.
FEEL THE LATEST HRRR / RAP FORECAST SOLUTIONS HAVE THE BEST
HANDLE ON THE PRESENT SITUATION. HAVE MODELED FORECAST TRENDS
ACCORDINGLY. LIKELY LOW CLOUDS AND FOG AHEAD OF THE FRONT WILL
IMPACT SE MA THAT INCLUDE CAPE COD AND THE ISLANDS INTO THE
MORNING HOURS. LOWS AROUND THE LOW-60S WITH THE WARM SPOTS SE
AND COOLEST AREAS NW.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH 6 PM THURSDAY/...
THURSDAY...
POST FRONTAL AIRMASS OVERSPREADS THE REGION AS COLD FRONT DEPARTS
THE SOUTH COAST DURING THE EARLY MORNING. MID LEVEL FLOW REMAINS
CYCLONIC AS MEAN TROUGH AXIS ALOFT REMAINS OVER NEW ENGLAND.
HOWEVER STRONG DRYING THROUGH THE COLUMN WITH NEGATIVE K-INDICES
OVERSPREADING THE REGION ALONG WITH DEW PTS TUMBLING INTO THE 50S
AND POSSIBLY THE U40S. HOWEVER GIVEN THE COOL TEMPS ALOFT AND
CYCLONIC FLOW SHOULD SEE SCT-BKN CU/SCU DURING THE PEAK HEATING
HOURS OF THE AFTERNOON.
NEVERTHELESS A SPECTULAR DAY WITH LOW HUMIDITY...A REFRESHING NW
BREEZE OF 10 TO 20 MPH AND TEMPS NOTICEABLY COOLER WITH HIGHS 75
TO 80.
HIGH SURF....
HURRICANE CRISTOBAL PASSES WELL OFFSHORE BUT WNA AND THE HURRICANE
VERSION OF THE WNA YIELDS 5-10 FT SWELLS ENTERING THE NEAR SHORE
WATERS AND UP TO 12 FT WELL SOUTH OF MVY AND ACK. OUR IN HOUSE
SURF CALCULATION SUGGEST BREAKERS OF 6-12 FT AT SOUTH FACING OCEAN
BEACHES TOMORROW. THUS VERY DANGEROUS SURF AND RIP CURRENTS.
OBVIOUSLY WILL CONTINUE THE HIGH SURFACE ADVISORY WHICH MAY HAVE
TO BE EXTENDED INTO FRI AS THE WAVE MODELS TYPICALLY ERODE SWELL
ENERGY TOO QUICKLY. SURF AND RIP CURRENTS WILL NOT BE AS DANGEROUS
ALONG THE EASTERN MA COAST AS THE SWELL ENERGY WILL BE PARALLEL TO
THIS COASTLINE.
THURSDAY NIGHT...
CORE OF COOL AIRMASS MOVES OVER THE REGION WITH 850 MB AND 925 MB
TEMPS ABOUT +1 SD COOLER THAN NORMAL. N-NE WINDS WILL PRECLUDE
EASTERN MA FROM COOLING OFF TOO /L60S/ MUCH GIVEN OCEAN WIND
TRAJECTORY. HOWEVER INTERIOR VALLEYS THAT DECOUPLE COULD SEE MINS
IN THE MU40S WITH 50S ELSEWHERE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
*/ HIGHLIGHTS...
- SEASONABLE AND DRY WEATHER FOR FRIDAY...ENJOY IT!
- HOT AND HUMID CONDITIONS THROUGH THE WEEKEND
- THUNDERSTORMS POSSIBLE ACROSS N/W NEW ENGLAND SUNDAY
- WET WEATHER ANTICIPATED SUNDAY NIGHT INTO MONDAY NIGHT
- COULD REMAIN WARMER THAN AVERAGE INTO NEXT WEEK
*/ OVERVIEW AND MODEL PREFERENCE...
BETTER AGREEMENT AMONG ENSEMBLE MEMBERS WOULD SUGGEST A ZONAL FLOW
REGIME WITH SOME WEAK RIDGING AS BOTH THE NAO/PNA REMAIN NEGATIVE TO
NEAR-NEUTRAL. EXPECTING AN ABOVE AVERAGE TEMPERATURE PATTERN AS THE
ECENS/GEFS/NAEFS/CPC WOULD SUGGEST INTO EARLY SEPTEMBER...ANOMALOUS
ON THE ORDER OF +2-3 STANDARD DEVIATIONS. WITH ANTICIPATED WARMER
CONDITIONS SUBSEQUENT OF RIDGING...EXPECTING PROLONGED S-FLOW TO
ADVECT MUGGY CONDITIONS N. LOOKING TO BE A WARM AND HUMID TIMEFRAME.
FOR THE FORECAST PERIOD OVER THE NEXT WEEK BEGINNING FRIDAY...EXPECT
THE W-ATLANTIC RIDGE TO BE THE DOMINANT INFLUENCE OVER THE REGIONS
WEATHER. FAVOR THE ECMWF WITH THE CONFLUENT FLOW SETUP AND ATTENDANT
SURFACE FRONTAL POSITION BETWEEN THE NE-CANADA TROUGH AND W-ATLANTIC
RIDGE REMAINING N OF THE REGION PARENT WITH BETTER JET-DYNAMICS AND
SHEARED MID-LEVEL ENERGY. ONLY AS A C-CONUS DISTURBANCE INVOKES A
WEAK-WAVE LOW ALONG THE FRONT WILL WET-WEATHER SHIFT INTO OUR AREA
AROUND MONDAY BASED ON A CONSENSUS OF MODEL DATA.
DESPITE MODEL VARIANCE...A BROAD SIGNAL IS DISCERNIBLE OF A BRIEF
PERIOD OF DRY WEATHER AFTER PASSAGE OF THE WEAK-WAVE
LOW...FOLLOWED BY A SHARP COLD FRONT AND PERHAPS THE RETURN OF
MORE SEASONABLE CONDITIONS. LOW CONFIDENCE AT THIS TIME AS
ENSEMBLE MEANS WOULD SUGGEST THE PROPENSITY FOR ZONAL-FLOW WITH
WEAK RIDGING. FAVOR THE DETERMINISTIC ECMWF WITH POSSIBLE
OUTCOMES.
HIGHLIGHTS/CONFIDENCE ARE BROKEN DOWN IN THE DAILY DISCUSSION BELOW.
*/ DAY-TO-DAY DETAILS...
FRIDAY...
HIGH PRESSURE. LIGHT/VARIABLE WINDS. SEA-BREEZES ALONG THE COASTS.
SEASONABLE AND MOSTLY CLEAR CONDITIONS...SLIGHTLY COOLER ALONG THE
SHORES...WITH HIGHS AROUND THE MID-70S. MID- TO HIGH-LEVEL CLOUDS
POSSIBLE AHEAD OF AN ENCROACHING WARM-FRONT FROM THE SW. ALONG WITH
WINDS TURNING S OVERNIGHT AS HIGH PRESSURE SHIFTS E...EXPECT MILDER
CONDITIONS WITH LOWS AROUND THE MID-50S.
SATURDAY...
SURFACE WARM FRONT LIFTING NE ACROSS NEW ENGLAND LATE...JOINING WITH
A TRAILING COLD FRONT FROM A LOW DISTURBANCE OVER NE-CANADA. AS THE
RIDGE SUBSEQUENTLY ENHANCES AHEAD OF THE FRONTAL DISTURBANCE AND A
WEAKER DISTURBANCE OVER THE C-CONUS...BELIEVE WET-WEATHER ACTIVITY
WILL BE PUSHED WELL N OF THE REGION BY THE INFLUENCE OF THE RIDGE.
THUS WILL GO WITH A DRY-WEATHER FORECAST.
EXPECT PREVAILING S-FLOW TO BEGIN USHERING WARMER / HUMID CONDITIONS
ACROSS THE REGION. WILL SEE HIGHS WARM INTO THE LOW-80S AS A WELL-
MIXED BOUNDARY LAYER ALLOWS FOR SCATTERED CUMULUS ALONG WITH THE MIX-
DOWN OF BREEZY S/SW FLOW. FEEL THIS WILL RESTRICT SEA-BREEZES...SO
EXPECT INTERIOR WINDS TO PUSH THE WARM / HUMID CONDITIONS ALL THE
WAY TO THE E-SHORES.
MILD AND DRY OVERNIGHT. WITH A LINGERING DRY-SUBSIDENCE INVERSION...
HIGHER DEWPOINT AIR ADVECTING N COULD LEND TO LOW CLOUDS / FOG ALONG
THE S-SHORE. EXPECTING LOWS AROUND THE LOW- TO MID-60S.
SUNDAY...
WARM-FRONT WELL-DEFINED TO THE N. PUSH OF H85 +16-18C AIR ACROSS THE
REGION. EXPECT S NEW ENGLAND TO BE WITHIN THE WARM-SECTOR OF A HOT
AND HUMID AIRMASS. COLLOCATED WITHIN A WELL-MIXED BOUNDARY LAYER...
BREEZY S/SW-FLOW DURING THE DAY SHOULD ALLOW FOR INTERIOR WINDS ONCE
AGAIN TO RESTRICT SEA-BREEZES AND PUSH FORECAST HIGH TEMPERATURES
AROUND THE UPPER-80S TO THE E-SHORES.
HEIGHTS FALL AS THE C-CONUS DISTURBANCE SHIFTS E WITHIN THE QUASI-
ZONAL FLOW REGIME. SHOWERS / THUNDERSTORMS ARE CERTAINLY PLAUSIBLE N
AND W WITHIN MODEST INSTABILITY AND SHEAR...CLOSER TO REGIONS OF
FAVORABLE DYNAMICS / ASCENT AS WELL AS THE CONVERGENT NOSE OF HIGHER
THETA-E AIR AHEAD OF THE FRONT. LIKELY THE MAJORITY OF ACTIVITY IS
ACROSS THE E GREAT LAKES INTO NY/PA...BUT ITS POSSIBLE THAT ACTIVITY
DEVELOPS INTO N/W NEW ENGLAND LATE. THIS WOULD POSSIBLY BE THE CASE
AS THE CONVECTIVE TEMPERATURE IS MET SUCH THAT ANY INVERSION WOULD
ERODE AND BOTH SURFACE-BASED INSTABILITY AND EFFECTIVE SHEAR COULD
BE UTILIZED. CAN NOT RULE OUT STRONG STORMS...ESPECIALLY ACROSS S/W
FACING SLOPES OF HIGH TERRAIN OVER NW CT / W MA / S NH AS OROGRAPHIC
PROCESSES AID IN LIFTING THE WARM / JUICY AIRMASS ALOFT. BUT IT IS
POSSIBLE THAT THE RIDGE WINS OUT. STILL A FORECAST WAY OUT IN TIME
AND AS WE HAVE SEEN JUST IN THE PAST SEVERAL MODEL RUNS THERE HAS
BEEN A FAIR AMOUNT OF VARIABILITY. HAVE MODERATE CONFIDENCE WITH
THIS FORECAST TIMEFRAME.
RIDGE AND SUBSIDENCE INVERSION LINGERS FOR THE S/E SO WILL KEEP WITH
A DRY-FORECAST FOR THOSE AREAS.
SUNDAY NIGHT THROUGH MONDAY NIGHT...
WEAK-WAVE LOW ALONG THE FRONT THROUGH THE QUASI-ZONAL FLOW PUSHES E
AND ACROSS THE REGION. THOUGH APPEARING AS A NOCTURNAL PASSAGE...THE
COLLOCATION OF DEEP-LAYER MOISTURE...MINOR INSTABILITY AND SHEAR...
AND FORCING ALONG THE FRONTAL BOUNDARY WILL LIKELY YIELD WIDESPREAD
SHOWERS WITH THE POSSIBILITY OF HEAVY RAIN AND THUNDERSTORMS. THOUGH
IT APPEARS THE BETTER FORCING DYNAMICS SHIFT N/E...SHUNTED BY THE
RIDGING PATTERN AND BERMUDA HIGH REMAINING DOMINANT.
LOW CONFIDENCE FORECAST AS THE CONSENSUS OF MODEL SOLUTIONS CONTAINS
A FAIR AMOUNT OF VARIABILITY. WILL PREVAIL WITH SLIGHTLY ABOVE-
AVERAGE CONDITIONS.
TUESDAY ONWARD...
A LULL IN ACTIVITY IS POSSIBLE BEHIND THE WEAK-WAVE DISTURBANCE. A
SHARPER COLD FRONT INTO MIDWEEK FOLLOWED BY HIGH PRESSURE. NOT ALL
ENTIRELY CONVINCED ON SUCH OUTCOMES BASED ON ENSEMBLE TRENDS. WOULD
ANTICIPATE RIDGING TO REMAIN DOMINANT WITH TEMPERATURES BEING ABOVE-
AVERAGE FOR THE TIMEFRAME.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT-TERM /TODAY THROUGH THURSDAY/...MODERATE CONFIDENCE.
TSRA CONCLUDING TOWARDS 2Z EVOLVING INTO A SHRA-LINE PROGRESSING
SE TOWARDS ACK BY MORNING. VFR REARWARD OF THE LINE UNDER NW
WINDS...WITH POSSIBLE IFR-LIFR CIGS / VSBYS ALONG AND AHEAD UNDER
S/SW FLOW...ESPECIALLY FOR S-COASTAL TERMINALS.
VFR INTO THURSDAY WITH GUSTY NW WINDS UP TO 20 KTS. SCT-BKN CIGS
AROUND 5 KFT DURING THE DAY...CLEARING OVERNIGHT WITH WINDS
WEAKENING TOWARDS FRIDAY MORNING.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. WILL HOLD VFR WITH SHRA
UNTIL 1Z. THEREAFTER...WINDS REVERTING NW AS CIGS LIFT.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. SHRA SHOULD MOVE OUT. NW
WINDS AND VFR PREVAIL. CIGS LIFTING.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY...HIGH CONFIDENCE.
VFR. LIGHT WINDS. SEA-BREEZES ALONG THE SHORES. SKC.
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
VFR. BREEZY S/SW WINDS. SCT CIGS 4-6 KFT SATURDAY. MVFR-IFR CIGS /
VSBYS POSSIBLE ALONG THE S-COAST SATURDAY NIGHT. SHRA/TSRA POSSIBLE
FOR N/W NEW ENGLAND LATE SUNDAY.
SUNDAY NIGHT INTO MONDAY...LOW CONFIDENCE.
MIX OF LOW-END VFR TO MVFR. WIDESPREAD SHRA ACROSS THE TERMINALS.
POSSIBLE TSRA. CONTINUED S/SW WINDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT-TERM /TONIGHT THROUGH THURSDAY/...HIGH CONFIDENCE.
TONIGHT...
SOUTH SWELLS FROM CRISTOBAL CONTINUE TO INCREASE. A FEW SHOWERS
POSSIBLE THIS EVENING AND OVERNIGHT. SSW WINDS BECOME NW TOWARD
SUNRISE AS COLD FRONT APPROACHES FROM THE WEST.
THURSDAY...
SWELLS PEAK AT 5 TO 11 FT TOMORROW ACROSS THE SOUTH COAST WATERS.
ADDING TO THE ROUGH SEAS WILL BE A DEVELOPING NW WIND WAVE BEHIND
THE FRONTAL PASSAGE. OTHERWISE DRY WEATHER WITH GOOD VSBY. HOWEVER
A FEW SHOWERS MAY LINGER EARLY IN THE MORNING ACROSS THE SOUTH
COASTAL WATERS.
THURSDAY NIGHT...
NW WINDS BECOME N-NE LATE. GOOD VSBY AND DRY WEATHER.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY...HIGH CONFIDENCE.
HIGH PRESSURE IN CONTROL. LIGHT WINDS. DIMINISHING SEAS WITH ONLY
THE S/SE OUTER WATERS EXPERIENCING WAVE HEIGHTS IN EXCESS OF 5-FEET
BY MORNING. GOOD BOATING WEATHER.
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
INCREASING S-WINDS. PROLONGED S-FETCH LENDING TO WAVE HEIGHTS IN
EXCESS OF 5-FEET ACROSS THE S/SE WATERS. FOG POSSIBLE DURING THE
OVERNIGHT HOURS...ESPECIALLY ALONG THE S-COAST.
MONDAY...MODERATE CONFIDENCE.
CONTINUED S-WINDS. WET-WEATHER MOVING ACROSS THE WATERS. FOG MAY
REMAIN AN ISSUE OVER THE WATERS...ESPECIALLY DURING OVERNIGHT
PERIODS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...AIR QUALITY ALERT UNTIL 9 PM EDT THIS EVENING FOR CTZ002>004.
MA...HIGH SURF ADVISORY UNTIL 8 PM EDT THURSDAY FOR MAZ020-022>024.
NH...NONE.
RI...HIGH SURF ADVISORY UNTIL 8 PM EDT THURSDAY FOR RIZ006>008.
AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>005.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT FRIDAY
FOR ANZ235-237-254>256.
&&
$$
SYNOPSIS...NOCERA/SIPPRELL
NEAR TERM...NOCERA/SIPPRELL
SHORT TERM...NOCERA
LONG TERM...SIPPRELL
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
525 AM EDT TUE AUG 26 2014
...UPDATED AVIATION SECTION FOR LOWER STRATUS POTENTIAL EARLY THIS
MORNING AT KLAL AND KTPA...
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A PATTERN THAT HAS NOT
BEEN ALL THAT COMMON THIS SUMMER. IT IS HARD TO BELIEVE...BUT THE
MID/UPPER LEVEL PATTERN CONSISTS OF LONGWAVE TROUGHING OVER THE
WESTERN CONUS...AND DOWNSTREAM AMPLIFIED RIDGING EXTENDING FROM THE
SOUTHERN PLAINS TO THE EASTERN SEABOARD. MUCH OF THIS SUMMER SEASON
HAS BEEN THE OPPOSITE WITH A STUBBORN TROUGH OVER THE EAST. THE
FLORIDA PENINSULA RESIDES MAINLY SOUTH OF THIS LARGE RIDGE IN A DEEP
LAYER NORTHEAST FLOW REGIME BETWEEN THIS FEATURE AND WHAT IS NOW
HURRICANE CRISTOBAL SPINNING TO THE EAST OF THE BAHAMAS. THIS
NORTHEAST FLOW IS DELIVERING A VERY ANOMALOUS MID-LEVEL AIRMASS
ABOVE OUR HEADS IN TERMS OF TEMPERATURES AND DRY AIR FOR THE NEXT
24-36 HOURS. THIS AIRMASS IS ALREADY ARRIVING PER WV IMAGERY AND THE
LATEST KTBW SOUNDING PROFILE...AND WILL ONLY FURTHER DRY OUT
OVERNIGHT INTO TUESDAY MORNING. THE KTBW EVENING SOUNDING SHOWED A
PW VALUES ALREADY DOWN TO 1.27"...WITH DECENT DEWPOINT DEPRESSIONS
ABOVE THE DIURNAL MIXED LAYER ALL THE WAY UP THROUGH THE TROP
COLUMN. THIS PW VALUE IS SLIGHTLY MORE THAN 2 STANDARD DEVIATIONS
BELOW CLIMATOLOGY FOR THE LAST WEEK OF AUGUST...AND EXPECT PW VALUES
DURING THE DAY ON TUESDAY TO DROP EVEN FURTHER. MINIMUM ALL TIME
VALUES FOR LATE AUGUST ARE AROUND 0.8". WE WILL NOT GET DOWN THAT
MUCH...BUT STILL AN INCREDIBLY DRY COLUMN FOR THIS TIME OF YEAR.
THE OTHER AND EVEN MORE IMPRESSIVE FEATURE OF THIS AIRMASS IS THE
MID-LEVEL TEMPS. FOR SIMPLICITY LETS FOCUS IN ON THE 500MB / H5
TEMPERATURES. THE KTBW SOUNDING MEASURED A TEMPERATURE OF -2C.
TEMPERATURES THIS WARM ARE ALMOST UNHEARD OF IN AUGUST...AND IT IS
FORECAST BY THE RELIABLE GUIDANCE TO WARM ANOTHER DEGREE OR 2 TODAY.
USING THE NAEFS (NORTH AMERICAN ENSEMBLE FORECAST SYSTEM) COMPARED
TO THE CFSR (CLIMATE FORECAST SYSTEM REANALYSIS 1979-2009)
CLIMATOLOGY FOR A 3 WEEK PERIOD CENTERED ON TODAY...WE FIND THAT THE
FORECAST H5 TEMPS ABOVE THE FL PENINSULA ARE ALL ABOVE THE 99TH
PERCENTILE OF VALUES...WITH MUCH OF THE AREA AT H5 EXPERIENCING
TEMPS HIGHER THAN ANYTHING SEEN IN THIS 30 YEAR CLIMATOLOGICAL
RECORD. SUCH ANOMALOUS VALUES ARE JUST INTERESTING FROM A CLIMATE
AND METEOROLOGICAL PERSPECTIVE. SO...GUESS WHAT? DO NOT SEE MUCH IN
THE WAY OF DEEP CONVECTION AROUND TODAY (IF ANY).
AT THE SURFACE...WE ARE EXPERIENCING A TIGHT GRADIENT AND ELEVATED
NORTHEAST FLOW BETWEEN 1020+MB HIGH PRESSURE TO OUR NORTH...AND
HURRICANE CRISTOBAL TO OUR EAST. EXPERIENCED A GUSTY DAY ON MONDAY
WITHIN THIS GRADIENT...HOWEVER THE REAL IMPACTS HAVE BEEN OVER THE
COASTAL WATERS OF THE EASTERN GULF...WHERE A RARE SUMMER ADVISORY
EVENT IS UNDERWAY EARLY THIS MORNING. THIS ADVISORY SHOULD BE
BRIEF IN DURATION WITH WINDS DROPPING SOMEWHAT DURING THE DAY ON
TUESDAY...AND THEN IMPROVING CONDITIONS THROUGH THE MIDDLE OF THE
WEEK.
&&
.SHORT TERM (TODAY THROUGH WEDNESDAY)...
TODAY...
JUST ABOUT AS QUIET A SUMMER DAY IN TERMS OF DEEP CONVECTION AS WE
SEE DURING THE SUMMER MONTHS. THE ATMOSPHERE ABOVE 850MB IS VERY
HOSTILE TOWARD CONVECTIVE COLUMNS THROUGHOUT THE FORECAST AREA AND
WILL REMAIN SO THROUGH THE DAY. MINIMUM THETAE VALUES BETWEEN 850MB
AND 500MB ARE BELOW 320K...AND IN SOME GUIDANCE MEMBERS DOWN BELOW
315K. THIS IS ABOUT AS LOW AS WE SEE THIS TIME OF YEAR AND THE DEPTH
OF THESE LOW VALUES SUGGESTS MAINLY A SHALLOW CU FIELD WITH LITTLE
IN THE WAY OF VERTICAL GROWTH BEFORE SIGNIFICANT ENTRAINMENT OF THIS
LOW THETAE AIR BEGINS. WITH THIS IN MIND...HAVE RAIN CHANCES DOWN AT
10% OR LESS TODAY FOR ALL AREAS. THERE IS SOME ATLANTIC MOISTURE IN
THE LOWEST LEVELS OF THE ATMOSPHERE TO SUPPORT THE SHALLOW CU
FIELD...BUT CAN NOT SEE ANYTHING MORE THAN A FEW ISOLATED AND
SHALLOW SPEED CONVERGENCE SPRINKLES MAKING THERE WAY INTO THE
FORECAST AREA WITHIN THE NE FLOW FROM THE ATLANTIC COAST. SOME OF
THE HIRES GUIDANCE MEMBERS TRY TO PRODUCE A FEW SHOWERS RIGHT AT THE
GULF COAST VERY LATE IN THE DAY AS THE LOCAL GRADIENT DIURNALLY
WEAKENS OVER THE NEARSHORE WATERS AND PROVIDES A BRIEF WINDOW OF
SURFACE FOCUS/CONVERGENCE FOR UPWARD MOTION. HOWEVER...THESE MODELS
ARE GENERALLY A BIT AGGRESSIVE...AND WILL HOLD WITH THE IDEA THAT
THE COLUMN IS SIMPLY TO HOSTILE FOR ANY OF THESE SHOWERS TO GET
ESTABLISHED.
SO...LOOK FOR A GENERALLY DRY DAY UNDER A FEW-SCT CU FIELD AND
TEMPERATURES CLIMBING INTO THE LOWER TO MIDDLE 90S. WINDS WILL
BECOME A LITTLE GUSTY WITHIN A FEW HOURS OF SUNRISE...BUT LIKELY
WILL NOT BE AS PRONOUNCED AS THEY WERE ON MONDAY.
TONIGHT...
NOT MUCH SENSIBLE WEATHER TO TALK ABOUT. THE DRY CONDITIONS WILL
CONTINUE OTHER THAN AN ISOLATED SPEED CONVERGENCE SPRINKLE MAKING IT
FAR ENOUGH INLAND FROM THE EAST COAST TO REACH EASTERN
POLK/HIGHLANDS COUNTIES. THE LOSS OF DIURNAL MIXING WILL END THE
GUSTY NATURE TO THE WINDS QUICKLY AFTER SUNSET OVER THE LANDMASS.
WINDS WILL ACTUALLY INCREASE AT THIS POINT OVER THE COASTAL WATERS
ONCE AGAIN...AND MORE CAN BE READ ABOUT THIS NEXT EASTERLY NOCTURNAL
SURGE IN THE MARINE DISCUSSION BELOW.
WEDNESDAY LOOKS TO BE ANOTHER GENERALLY QUIET DAY FOR MUCH OF THE
FORECAST AREA AS DRY AND WARM AIR REMAIN OVERHEAD. SOME UNCERTAINLY
IN THE THUNDERSTORM CHANCES DOWN TOWARD THE FORT MYERS FOR THE
SECOND HALF OF THE AFTERNOON AND EVENING AS THERE IS SOME
DISAGREEMENT IN THE GUIDANCE AS TO THE RATE OF MOISTURE RETURN AND
LOW LEVEL FOCUS RETURN FROM THE SOUTH. ALL THE RELIABLE GUIDANCE
MEMBERS HAVE A WEAK TROUGH EXTENDING ACROSS THE SOUTHEAST GULF AND
FLORIDA STRAITS ON WEDNESDAY. THIS TROUGH AXIS MARKS THE LEADING
EDGE OF THE DEEP LAYER MOISTURE AND NOSE OF AN EXPANDING LOW LEVEL
THETAE RIDGE. THE 00Z NAM IS THE MOST AGGRESSIVE WITH THE NORTHWARD
PROGRESSION OF THIS THETAE RIDGE AND BRINGS A DECENT SWATH OF
MOISTURE RETURN AND RESULTING VERTICAL MOTION BELOW 700MB INTO THE
SOUTHERN FL PENINSULA...INCLUDING LEE/CHARLOTTE COUNTIES LATE IN THE
DAY. THE GFS IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE...WITH THE
00Z ECMWF THE SLOWEST AND LEAST AGGRESSIVE TO BRING THE MOISTURE
BACK TO OUR SOUTHERN ZONES. THE NAM UPGRADE FROM EARLIER THIS MONTH
IS STILL FAIRLY RECENT AND THERE HAS NOT BEEN ENOUGH TIME TO REALLY
FIGURE OUT ALL ITS BIASES ETC. NOT GOING TO SAY ITS SOLUTION IS NOT
CORRECT...BUT FOR THIS FORECAST CYCLE...A MORE CONSERVATIVE
PHILOSOPHY IN LINE WITH THE GFS SEEMS MORE APPROPRIATE. WILL BRING A
CHANCE FOR A FEW LATE DAY STORMS INTO THE FORT MYERS AREA...BUT KEEP
LIKELY WORDING OUT OF THE FORECAST (AS THE NAM WOULD SUGGEST).
FURTHER NORTH...TOWARD TAMPA BAY AND THE NATURE COAST...CONFIDENCE
IS HIGHER IN NO SIGNIFICANT MOISTURE RETURN DURING THE DAYLIGHT
HOURS. TOUGH THIS TIME OF YEAR AS A FORECASTER TO GO YET ANOTHER DAY
WITH NO STORM CHANCES...BUT WILL STILL KEEP RAIN CHANCES WELL BELOW
CLIMO...WITH JUST A 15-20% POP FOR MOST AREAS. NORTH OF BROOKSVILLE
IS THE ONLY PLACE CONFIDENCE IS HIGH ENOUGH TO LEAVE RAIN MENTION
OUT OF THE FORECAST. THURSDAY LOOKS TO BE THE TRUE TRANSITION DAY
FOR MOST AREAS...WITH DEEPER LAYER MOISTURE AND INCREASING STORMS
CHANCES EXPANDING NORTHWARD ACROSS THE PENINSULA.
&&
.LONG TERM (THURSDAY THROUGH NEXT MONDAY)...
A COMPACT UPPER RIDGE INITIALLY ACROSS SOUTH GA AND NORTH FL BUILDS
AND ELONGATES...EXTENDING FROM THE NORTHERN GULF TO THE ATLANTIC
WATERS OFF THE SOUTHEAST AND MID-ATLANTIC COASTS. THIS RIDGE
DOMINATES THE AREA ALTHOUGH A WEAK UPPER LOW/TROUGH APPROACHES THE
BAHAMAS BY THE END OF THE PERIOD. MEANWHILE AT THE SURFACE CRISTOBAL
EXITS AS HIGH PRESSURE BEGINS TO RIDGE IN ACROSS SOUTH FL. THIS
LIFTS INTO CENTRAL FL FRI AND CONTINUES NORTHWARD...RESIDING ACROSS
NORTHERN FL THROUGH THE HOLIDAY WEEKEND WITH A BROAD AND RELAXED
PRESSURE PATTERN.
THE UPPER RIDGE WILL HELP KEEP TEMPERATURES ON THE WARM SIDE OF
NORMAL...WITH THE HIGHS ABOVE NORMAL BY A COUPLE OF DEGREES. THE
SURFACE RIDGE SLIDING NORTH PROVIDES ENOUGH MOISTURE...MODEL PWAT
VALUES RUN IN THE 1.9 TO 2 INCH RANGE...FOR ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS. SOUTHEAST BECOMING SOUTHERLY LOW LEVEL
FLOW...BUT WITH ONSHORE FLOW IN THE AFTERNOONS...WILL RESULT IN THE
MOST COVERAGE INLAND IN THE AFTERNOON AND EVENING HOURS. ISOLATED
OVERNIGHT ACTIVITY ON THE GULF MAY DRIFT OVER SOME COASTAL LOCATIONS
IN THE MORNINGS.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS MUCH THE FORECAST AREA EARLY THIS
MORNING. HAVE SEEN AN AREA OF LOWER STRATUS WITH CEILINGS IN THE IFR
RANGE DEVELOP ALONG AND NORTH OF THE I-4 CORRIDOR IN PAST COUPLE OF
HOURS. HAVE INCLUDED TEMPOS FOR BRIEF IFR CIGS AT KLAL AND KTPA
THROUGH EARLY THIS MORNING. ANY CIG RESTRICTIONS ALONG THE I-4
CORRIDOR SHOULD LIFT WITHIN A FEW HOURS OF SUNRISE. ELSEWHERE VFR
CONDITIONS WILL PREVAIL. CHANCES FOR THUNDERSTORMS TODAY ARE VERY
LOW FOR ALL THE TERMINALS. ONLY AVIATION CONCERNS WILL BE GUSTY
NORTHEAST WINDS FROM MID MORNING THROUGH THE AFTERNOON HOURS. WINDS
WILL BECOME LESS GUSTY AFTER SUNSET THIS EVENING.
&&
.MARINE...
A TIGHT GRADIENT BETWEEN HIGH PRESSURE TO OUR NORTH AND HURRICANE
CRISTOBAL TO THE EAST OF FLORIDA ARE RESULTING IN AN UNSEASONABLY
STRONG EAST TO NORTHEAST FLOW ACROSS THE EASTERN GULF OF MEXICO.
ADVISORY LEVEL WINDS WILL CONTINUE EARLY THIS MORNING OVER THE
COASTAL WATERS AND THEN SLOWLY SUBSIDE BELOW HEADLINE CRITERIA
THROUGH THE MORNING HOURS. ANOTHER PERIOD OF CAUTIONARY LEVEL WINDS
IS EXPECTED TONIGHT INTO EARLY WEDNESDAY MORNING BEFORE ONCE AGAIN
SUBSIDING DURING THE THE DAYLIGHT HOURS. WINDS AND SEAS SHOULD THEN
REMAIN BELOW HEADLINE CRITERIA FOR THE REMAINDER OF THE FORECAST
PERIOD.
&&
.FIRE WEATHER...
DESPITE DRIER CONDITIONS AND LITTLE TO NO RAIN CHANCES TODAY...
RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. WINDS
HOWEVER WILL BE GUSTY OUT OF THE NORTHEAST AND EAST. MOISTURE AND
CHANCES FOR AFTERNOON STORMS WILL BEGIN TO INCREASE ONCE AGAIN
DURING THE MIDDLE PORTION OF THE WEEK AND BE BACK TO NORMAL LATE
AUGUST CONDITIONS BY THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 94 75 94 78 / 10 10 20 10
FMY 95 74 94 78 / 10 10 40 20
GIF 93 72 94 74 / 10 10 20 10
SRQ 94 74 94 77 / 10 10 20 10
BKV 94 70 94 71 / 10 10 20 10
SPG 94 79 93 80 / 10 10 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD
TO TARPON SPRINGS OUT 20 TO 60 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 NM-ENGLEWOOD TO
TARPON SPRINGS OUT 20 NM-TARPON SPRINGS TO SUWANNEE
RIVER OUT 20 NM.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM...RUDE
AREA FORECAST DISCUSSION...RESENT
NWS TAMPA BAY RUSKIN FL
422 AM EDT TUE AUG 26 2014
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A PATTERN THAT HAS NOT
BEEN ALL THAT COMMON THIS SUMMER. IT IS HARD TO BELIEVE...BUT THE
MID/UPPER LEVEL PATTERN CONSISTS OF LONGWAVE TROUGHING OVER THE
WESTERN CONUS...AND DOWNSTREAM AMPLIFIED RIDGING EXTENDING FROM THE
SOUTHERN PLAINS TO THE EASTERN SEABOARD. MUCH OF THIS SUMMER SEASON
HAS BEEN THE OPPOSITE WITH A STUBBORN TROUGH OVER THE EAST. THE
FLORIDA PENINSULA RESIDES MAINLY SOUTH OF THIS LARGE RIDGE IN A DEEP
LAYER NORTHEAST FLOW REGIME BETWEEN THIS FEATURE AND WHAT IS NOW
HURRICANE CRISTOBAL SPINNING TO THE EAST OF THE BAHAMAS. THIS
NORTHEAST FLOW IS DELIVERING A VERY ANOMALOUS MID-LEVEL AIRMASS
ABOVE OUR HEADS IN TERMS OF TEMPERATURES AND DRY AIR FOR THE NEXT
24-36 HOURS. THIS AIRMASS IS ALREADY ARRIVING PER WV IMAGERY AND THE
LATEST KTBW SOUNDING PROFILE...AND WILL ONLY FURTHER DRY OUT
OVERNIGHT INTO TUESDAY MORNING. THE KTBW EVENING SOUNDING SHOWED A
PW VALUES ALREADY DOWN TO 1.27"...WITH DECENT DEWPOINT DEPRESSIONS
ABOVE THE DIURNAL MIXED LAYER ALL THE WAY UP THROUGH THE TROP
COLUMN. THIS PW VALUE IS SLIGHTLY MORE THAN 2 STANDARD DEVIATIONS
BELOW CLIMATOLOGY FOR THE LAST WEEK OF AUGUST...AND EXPECT PW VALUES
DURING THE DAY ON TUESDAY TO DROP EVEN FURTHER. MINIMUM ALL TIME
VALUES FOR LATE AUGUST ARE AROUND 0.8". WE WILL NOT GET DOWN THAT
MUCH...BUT STILL AN INCREDIBLY DRY COLUMN FOR THIS TIME OF YEAR.
THE OTHER AND EVEN MORE IMPRESSIVE FEATURE OF THIS AIRMASS IS THE
MID-LEVEL TEMPS. FOR SIMPLICITY LETS FOCUS IN ON THE 500MB / H5
TEMPERATURES. THE KTBW SOUNDING MEASURED A TEMPERATURE OF -2C.
TEMPERATURES THIS WARM ARE ALMOST UNHEARD OF IN AUGUST...AND IT IS
FORECAST BY THE RELIABLE GUIDANCE TO WARM ANOTHER DEGREE OR 2 TODAY.
USING THE NAEFS (NORTH AMERICAN ENSEMBLE FORECAST SYSTEM) COMPARED
TO THE CFSR (CLIMATE FORECAST SYSTEM REANALYSIS 1979-2009)
CLIMATOLOGY FOR A 3 WEEK PERIOD CENTERED ON TODAY...WE FIND THAT THE
FORECAST H5 TEMPS ABOVE THE FL PENINSULA ARE ALL ABOVE THE 99TH
PERCENTILE OF VALUES...WITH MUCH OF THE AREA AT H5 EXPERIENCING
TEMPS HIGHER THAN ANYTHING SEEN IN THIS 30 YEAR CLIMATOLOGICAL
RECORD. SUCH ANOMALOUS VALUES ARE JUST INTERESTING FROM A CLIMATE
AND METEOROLOGICAL PERSPECTIVE. SO...GUESS WHAT? DO NOT SEE MUCH IN
THE WAY OF DEEP CONVECTION AROUND TODAY (IF ANY).
AT THE SURFACE...WE ARE EXPERIENCING A TIGHT GRADIENT AND ELEVATED
NORTHEAST FLOW BETWEEN 1020+MB HIGH PRESSURE TO OUR NORTH...AND
HURRICANE CRISTOBAL TO OUR EAST. EXPERIENCED A GUSTY DAY ON MONDAY
WITHIN THIS GRADIENT...HOWEVER THE REAL IMPACTS HAVE BEEN OVER THE
COASTAL WATERS OF THE EASTERN GULF...WHERE A RARE SUMMER ADVISORY
EVENT IS UNDERWAY EARLY THIS MORNING. THIS ADVISORY SHOULD BE
BRIEF IN DURATION WITH WINDS DROPPING SOMEWHAT DURING THE DAY ON
TUESDAY...AND THEN IMPROVING CONDITIONS THROUGH THE MIDDLE OF THE
WEEK.
&&
.SHORT TERM (TODAY THROUGH WEDNESDAY)...
TODAY...
JUST ABOUT AS QUIET A SUMMER DAY IN TERMS OF DEEP CONVECTION AS WE
SEE DURING THE SUMMER MONTHS. THE ATMOSPHERE ABOVE 850MB IS VERY
HOSTILE TOWARD CONVECTIVE COLUMNS THROUGHOUT THE FORECAST AREA AND
WILL REMAIN SO THROUGH THE DAY. MINIMUM THETAE VALUES BETWEEN 850MB
AND 500MB ARE BELOW 320K...AND IN SOME GUIDANCE MEMBERS DOWN BELOW
315K. THIS IS ABOUT AS LOW AS WE SEE THIS TIME OF YEAR AND THE DEPTH
OF THESE LOW VALUES SUGGESTS MAINLY A SHALLOW CU FIELD WITH LITTLE
IN THE WAY OF VERTICAL GROWTH BEFORE SIGNIFICANT ENTRAINMENT OF THIS
LOW THETAE AIR BEGINS. WITH THIS IN MIND...HAVE RAIN CHANCES DOWN AT
10% OR LESS TODAY FOR ALL AREAS. THERE IS SOME ATLANTIC MOISTURE IN
THE LOWEST LEVELS OF THE ATMOSPHERE TO SUPPORT THE SHALLOW CU
FIELD...BUT CAN NOT SEE ANYTHING MORE THAN A FEW ISOLATED AND
SHALLOW SPEED CONVERGENCE SPRINKLES MAKING THERE WAY INTO THE
FORECAST AREA WITHIN THE NE FLOW FROM THE ATLANTIC COAST. SOME OF
THE HIRES GUIDANCE MEMBERS TRY TO PRODUCE A FEW SHOWERS RIGHT AT THE
GULF COAST VERY LATE IN THE DAY AS THE LOCAL GRADIENT DIURNALLY
WEAKENS OVER THE NEARSHORE WATERS AND PROVIDES A BRIEF WINDOW OF
SURFACE FOCUS/CONVERGENCE FOR UPWARD MOTION. HOWEVER...THESE MODELS
ARE GENERALLY A BIT AGGRESSIVE...AND WILL HOLD WITH THE IDEA THAT
THE COLUMN IS SIMPLY TO HOSTILE FOR ANY OF THESE SHOWERS TO GET
ESTABLISHED.
SO...LOOK FOR A GENERALLY DRY DAY UNDER A FEW-SCT CU FIELD AND
TEMPERATURES CLIMBING INTO THE LOWER TO MIDDLE 90S. WINDS WILL
BECOME A LITTLE GUSTY WITHIN A FEW HOURS OF SUNRISE...BUT LIKELY
WILL NOT BE AS PRONOUNCED AS THEY WERE ON MONDAY.
TONIGHT...
NOT MUCH SENSIBLE WEATHER TO TALK ABOUT. THE DRY CONDITIONS WILL
CONTINUE OTHER THAN AN ISOLATED SPEED CONVERGENCE SPRINKLE MAKING IT
FAR ENOUGH INLAND FROM THE EAST COAST TO REACH EASTERN
POLK/HIGHLANDS COUNTIES. THE LOSS OF DIURNAL MIXING WILL END THE
GUSTY NATURE TO THE WINDS QUICKLY AFTER SUNSET OVER THE LANDMASS.
WINDS WILL ACTUALLY INCREASE AT THIS POINT OVER THE COASTAL WATERS
ONCE AGAIN...AND MORE CAN BE READ ABOUT THIS NEXT EASTERLY NOCTURNAL
SURGE IN THE MARINE DISCUSSION BELOW.
WEDNESDAY LOOKS TO BE ANOTHER GENERALLY QUIET DAY FOR MUCH OF THE
FORECAST AREA AS DRY AND WARM AIR REMAIN OVERHEAD. SOME UNCERTAINLY
IN THE THUNDERSTORM CHANCES DOWN TOWARD THE FORT MYERS FOR THE
SECOND HALF OF THE AFTERNOON AND EVENING AS THERE IS SOME
DISAGREEMENT IN THE GUIDANCE AS TO THE RATE OF MOISTURE RETURN AND
LOW LEVEL FOCUS RETURN FROM THE SOUTH. ALL THE RELIABLE GUIDANCE
MEMBERS HAVE A WEAK TROUGH EXTENDING ACROSS THE SOUTHEAST GULF AND
FLORIDA STRAITS ON WEDNESDAY. THIS TROUGH AXIS MARKS THE LEADING
EDGE OF THE DEEP LAYER MOISTURE AND NOSE OF AN EXPANDING LOW LEVEL
THETAE RIDGE. THE 00Z NAM IS THE MOST AGGRESSIVE WITH THE NORTHWARD
PROGRESSION OF THIS THETAE RIDGE AND BRINGS A DECENT SWATH OF
MOISTURE RETURN AND RESULTING VERTICAL MOTION BELOW 700MB INTO THE
SOUTHERN FL PENINSULA...INCLUDING LEE/CHARLOTTE COUNTIES LATE IN THE
DAY. THE GFS IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE...WITH THE
00Z ECMWF THE SLOWEST AND LEAST AGGRESSIVE TO BRING THE MOISTURE
BACK TO OUR SOUTHERN ZONES. THE NAM UPGRADE FROM EARLIER THIS MONTH
IS STILL FAIRLY RECENT AND THERE HAS NOT BEEN ENOUGH TIME TO REALLY
FIGURE OUT ALL ITS BIASES ETC. NOT GOING TO SAY ITS SOLUTION IS NOT
CORRECT...BUT FOR THIS FORECAST CYCLE...A MORE CONSERVATIVE
PHILOSOPHY IN LINE WITH THE GFS SEEMS MORE APPROPRIATE. WILL BRING A
CHANCE FOR A FEW LATE DAY STORMS INTO THE FORT MYERS AREA...BUT KEEP
LIKELY WORDING OUT OF THE FORECAST (AS THE NAM WOULD SUGGEST).
FURTHER NORTH...TOWARD TAMPA BAY AND THE NATURE COAST...CONFIDENCE
IS HIGHER IN NO SIGNIFICANT MOISTURE RETURN DURING THE DAYLIGHT
HOURS. TOUGH THIS TIME OF YEAR AS A FORECASTER TO GO YET ANOTHER DAY
WITH NO STORM CHANCES...BUT WILL STILL KEEP RAIN CHANCES WELL BELOW
CLIMO...WITH JUST A 15-20% POP FOR MOST AREAS. NORTH OF BROOKSVILLE
IS THE ONLY PLACE CONFIDENCE IS HIGH ENOUGH TO LEAVE RAIN MENTION
OUT OF THE FORECAST. THURSDAY LOOKS TO BE THE TRUE TRANSITION DAY
FOR MOST AREAS...WITH DEEPER LAYER MOISTURE AND INCREASING STORMS
CHANCES EXPANDING NORTHWARD ACROSS THE PENINSULA.
&&
.LONG TERM (THURSDAY THROUGH NEXT MONDAY)...
A COMPACT UPPER RIDGE INITIALLY ACROSS SOUTH GA AND NORTH FL BUILDS
AND ELONGATES...EXTENDING FROM THE NORTHERN GULF TO THE ATLANTIC
WATERS OFF THE SOUTHEAST AND MID-ATLANTIC COASTS. THIS RIDGE
DOMINATES THE AREA ALTHOUGH A WEAK UPPER LOW/TROUGH APPROACHES THE
BAHAMAS BY THE END OF THE PERIOD. MEANWHILE AT THE SURFACE CRISTOBAL
EXITS AS HIGH PRESSURE BEGINS TO RIDGE IN ACROSS SOUTH FL. THIS
LIFTS INTO CENTRAL FL FRI AND CONTINUES NORTHWARD...RESIDING ACROSS
NORTHERN FL THROUGH THE HOLIDAY WEEKEND WITH A BROAD AND RELAXED
PRESSURE PATTERN.
THE UPPER RIDGE WILL HELP KEEP TEMPERATURES ON THE WARM SIDE OF
NORMAL...WITH THE HIGHS ABOVE NORMAL BY A COUPLE OF DEGREES. THE
SURFACE RIDGE SLIDING NORTH PROVIDES ENOUGH MOISTURE...MODEL PWAT
VALUES RUN IN THE 1.9 TO 2 INCH RANGE...FOR ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS. SOUTHEAST BECOMING SOUTHERLY LOW LEVEL
FLOW...BUT WITH ONSHORE FLOW IN THE AFTERNOONS...WILL RESULT IN THE
MOST COVERAGE INLAND IN THE AFTERNOON AND EVENING HOURS. ISOLATED
OVERNIGHT ACTIVITY ON THE GULF MAY DRIFT OVER SOME COASTAL LOCATIONS
IN THE MORNINGS.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS THE FORECAST AREA EARLY THIS MORNING
AND WILL CONTINUE FOR THE DURATION OF THE TAF PERIOD. CHANCES FOR
THUNDERSTORMS TODAY ARE VERY LOW FOR ALL THE TERMINALS. ONLY
AVIATION CONCERNS WILL BE GUSTY NORTHEAST WINDS FROM MID MORNING
THROUGH THE AFTERNOON HOURS. WINDS WILL BECOME LESS GUSTY AFTER
SUNSET THIS EVENING.
&&
.MARINE...
A TIGHT GRADIENT BETWEEN HIGH PRESSURE TO OUR NORTH AND HURRICANE
CRISTOBAL TO THE EAST OF FLORIDA ARE RESULTING IN AN UNSEASONABLY
STRONG EAST TO NORTHEAST FLOW ACROSS THE EASTERN GULF OF MEXICO.
ADVISORY LEVEL WINDS WILL CONTINUE EARLY THIS MORNING OVER THE
COASTAL WATERS AND THEN SLOWLY SUBSIDE BELOW HEADLINE CRITERIA
THROUGH THE MORNING HOURS. ANOTHER PERIOD OF CAUTIONARY LEVEL WINDS
IS EXPECTED TONIGHT INTO EARLY WEDNESDAY MORNING BEFORE ONCE AGAIN
SUBSIDING DURING THE THE DAYLIGHT HOURS. WINDS AND SEAS SHOULD THEN
REMAIN BELOW HEADLINE CRITERIA FOR THE REMAINDER OF THE FORECAST
PERIOD.
&&
.FIRE WEATHER...
DESPITE DRIER CONDITIONS AND LITTLE TO NO RAIN CHANCES TODAY...
RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. WINDS
HOWEVER WILL BE GUSTY OUT OF THE NORTHEAST AND EAST. MOISTURE AND
CHANCES FOR AFTERNOON STORMS WILL BEGIN TO INCREASE ONCE AGAIN
DURING THE MIDDLE PORTION OF THE WEEK AND BE BACK TO NORMAL LATE
AUGUST CONDITIONS BY THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 94 75 94 78 / 10 10 20 10
FMY 95 74 94 78 / 10 10 40 20
GIF 93 72 94 74 / 10 10 20 10
SRQ 94 74 94 77 / 10 10 20 10
BKV 94 70 94 71 / 10 10 20 10
SPG 94 79 93 80 / 10 10 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD
TO TARPON SPRINGS OUT 20 TO 60 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 NM-ENGLEWOOD TO
TARPON SPRINGS OUT 20 NM-TARPON SPRINGS TO SUWANNEE
RIVER OUT 20 NM.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM...RUDE
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1051 AM CDT TUE AUG 26 2014
.MESOSCALE DISCUSSION...
1051 AM CDT...
SCATTERED STRONG TO ISOLATED SEVERE STORMS CONTINUE TO DEVELOP
SOUTHEASTWARD ACROSS THE AREA. A WELL-DEFINED SHELF CLOUD WITH WINDS
ABOVE 35 MPH...POSSIBLY NEAR 50 MPH BASED ON TERMINAL DOPPLER
WEATHER RADAR DATA...IS MOVING SOUTHEASTWARD INTO THE CHICAGO METRO
AREA. UPDRAFTS CONTINUE TO DEVELOP ALONG THIS...WITH CORRELATING
DOWNDRAFTS OF STORMS BEING THE MOST CONCERNING FOR PUSHING WINDS TO
THE HIGHER MAGNITUDES.
MTF
PREV DISCUSSION...
328 AM CDT
SHOWER AND THUNDERSTORM CHANCES AND TIMING WILL BE THE MAIN FORECAST
CHALLENGE THROUGH THE PERIOD FOLLOWED BY TEMPS AS THEY MAY BE
INFLUENCED BY ROUNDS OF CONVECTION. WATER VAPOR IMAGERY SHOWS THE
UPPER WHICH CONTRIBUTED TO THE BREAKING DOWN OF THE PERSISTENT UPPER
RIDGE OVER THE AREA IS TRACKING NORTHEAST ACROSS JAMES BAY LEAVING
CORRIDOR OF FAIRLY ZONAL FLOW ACROSS THE UPPER MIDWEST AND GREAT
LAKES. ANOTHER UPPER LOW IS SLOWLY SPINNING SOUTHWARD ACROSS
NORTHERN CALIFORNIA AND NEVADA CUTTING OFF FROM A TROUGH AXIS TO THE
NORTH WHICH IS MOVING EAST ACROSS THE CANADIAN PRAIRIES. A RIDGE
AXIS IS PIVOTING EASTWARD OVER WESTERN CANADA AS AN UPPER TROUGH
MOVES EASTWARD ACROSS SOUTHERN ALASKA. AT THE SURFACE...LOW PRESSURE
IS OVER JAMES BAY WITH A COLD FRONT TRAILING IT ACROSS CENTRAL
WISCONSIN AND IOWA. ONE AREA OF HIGH PRESSURE IS STRETCHED UP AND
DOWN THE EASTERN SEABOARD WHILE ANOTHER HIGH IS OVER THE NORTHERN
PLAINS IN THE WAKE OF THE COLD FRONT.
TODAY...THE AFOREMENTIONED COLD FRONT TO THE NORTHWEST WILL BE
ENTERING THE CWA IN THE NEXT FEW HOURS BUT LOOKS TO GET HUNG UP NEAR
THE I-80 CORRIDOR FOR A TIME LATER THIS MORNING. CONVECTIVE TRENDS
ARE A CHALLENGE THIS MORNING WITH THE FRONT AND SEVERAL OTHER
FEATURES PRESENT TO KEEP SHOWERS AND THUNDERSTORMS GOING. EVENING
UPPER AIR ANALYSIS SHOWED AN UPPER JET CORE FROM SOUTHWEST MINNESOTA
TO JAMES BAY WHICH PLACES THE RIGHT ENTRANCE REGION OVER IOWA. THE
NOSE OF A LOW LEVEL JET IS AIMED INTO SOUTHEAST NEBRASKA BUT TURNS
WESTERLY ACROSS SOUTHERN IOWA. THIS HAS LED TO A DECENT DIFFERENTIAL
DIVERGENCE SET UP BETWEEN THE LOW LEVEL AND UPPER LEVEL JETS. IN
ADDITION...AN UPPER WAVE APPEARS TO BE TRACKING NORTHEAST ACROSS
NORTH CENTRAL KANSAS. ALL OF THIS IS LEADING TO VARYING DEGREES OF
CONVECTIVE DEVELOPMENT FROM EAST CENTRAL NEBRASKA/WEST CENTRAL
IOWA...WHERE THE COVERAGE IS EXTENSIVE...TO EASTERN IOWA AND NOW
JUST INTO NW ILLINOIS WHERE COVERAGE IS ISOLATED THUS FAR. 850-300
MB THICKNESS TAKES THIS ACTIVITY EASTWARD. HOW WELL THIS SUSTAINS
ITSELF IS IN QUESTION BUT GIVEN THAT THERE ARE SEVERAL LARGE SCALE
FACTORS DRIVING IT AND THERE IS A GOOD POOL OF INSTABILITY NEAR AND
AHEAD OF THE FRONT THERE IS GOOD REASON FOR IT TO CONTINUE. NOT TOO
MENTION THE TREND OF THE PAST SEVERAL DAYS HAS BEEN FOR MORNING
CONVECTION TO FESTER AND/OR SPIN OFF NEW CONVECTION MIDDAY ONWARD.
ISOLATED TO SCATTERED ACTIVITY WILL BEGIN TO AFFECT THE AREA IN THE
NEXT FEW HOURS WHILE THE MORE SOLID ACTIVITY OVER WEST CENTRAL IOWA
AND EAST CENTRAL NEBRASKA OR ACTIVITY SPUN OFF FROM IT WOULD
POTENTIALLY AFFECT THE AREA LATE MORNING/EARLY AFTERNOON. THIS
COMPLEX HAS BEEN ORGANIZING AND ACCELERATING EASTWARD TO SOME DEGREE
IN THE LAST HOUR OR SO. IN ADDITION...WITH THE FRONTAL BOUNDARY
LIKELY STILL IN THE SOUTHERN CWA THIS AFTERNOON IT MAY SERVE AS
FOCUS FOR NEW CONVECTION AS WELL. IT DOES APPEAR THAT POPS WILL
TAPER OFF ACROSS THE NORTH DURING THE LATE AFTERNOON. TORRENTIAL
DOWNPOURS AND LOCALIZED FLOODING WILL BE THE MAIN THREAT WITH ANY
STORMS ONCE AGAIN...WITH GUSTY STRAIGHT LINE WINDS AND ADDITIONAL
THREAT. MID LEVEL AIR WILL STILL BE QUITE WARM WITH H85 TEMPS NEAR
+20C BUT LOW LEVEL WINDS WILL TURN NORTHERLY AND EVEN NORTHEASTERLY
NEAR LAKE MICHIGAN. EXPECT HIGHS IN THE UPPER 80S FAR SOUTH AND NEAR
80 NEAR THE LAKE AND FAR NORTHERN INLAND AREAS...WITH LOW TO MID 80S
IN BETWEEN. CONVECTION COULD ONCE AGAIN HAVE AN IMPACT ON
HIGHS...ESPECIALLY SOUTH IF ACTIVITY CONTINUES INTO THE AFTERNOON
GIVEN THE BETTER PROXIMITY TO THE FRONTAL BOUNDARY.
TONIGHT THROUGH FRIDAY...CONVECTIVE CHANCES REMAIN A CHALLENGE THIS
PERIOD. THE SURFACE FRONT WILL BE TO THE SOUTH OF THE AREA BUT THE
MAIN MID LEVEL THERMAL GRADIENT WILL BE OVERHEAD AND EVEN NORTH OF
THE AREA. THE LOW AMPLITUDE UPPER TROUGH CURRENTLY WORKING INTO THE
CANADIAN PRAIRIES IN THE MAIN NORTHERN STREAM OF FLOW WILL BE
PASSING TO THE NORTH SUPPLYING MODEST HEIGHT FALLS TO THE LOCAL AREA
TONIGHT AND WEDNESDAY MORNING. THE RIGHT ENTRANCE OF THE UPPER JET
WILL ALSO BE PASSING OVER THE AREA. GUIDANCE SUGGESTS THAT THERE
WILL BE A WAVE EJECTING FROM THE CUTOFF UPPER TROUGH ACROSS THE
CENTRAL PLAINS AS WELL. IT APPEARS THAT CONVECTION WILL BE
DEVELOPING TO THE WEST TONIGHT THEN TRACK EASTWARD IN CONJUNCTION
WITH THE SYNOPTIC FEATURES. THIS SHOULD RESULT IN BEST CHANCES FOR
PRECIP LATER TONIGHT AND WEDNESDAY MORNING....THOUGH HAVE AN INKLING
THIS MAY BE A BIT FAST. THIS MAY BE ANOTHER SITUATION WHERE ACTIVITY
WILL BE DECAYING IN THE MORNING AS IS GETS CLOSER TO THE AREA. MUCH
OF THE AREA COULD SEE PRECIP BUT THE BEST FOCUS MAY BE ACROSS THE
SOUTH IN CLOSER PROXIMITY TO THE FRONT. THE CUTOFF UPPER LOW WILL BE
SLOWLY BUT STEADILY MOVING EASTWARD FORCING MODEST RIDGING INTO THE
AREA GOING INTO THURSDAY. THIS WILL BRING ANOTHER PUSH OF WARM
ADVECTION ACROSS THE CENTRAL U.S. WEDNESDAY NIGHT AND DRIVE THE
FRONTAL BOUNDARY NORTH AS A WARM FRONT. AT THIS POINT THE BULK OF
THE CONVECTION LOOKS TO BE TO THE WEST WEDNESDAY NIGHT WITH IT THEN
AFFECTING THE CWA THURSDAY...WITH BEST CHANCES NORTH AS THE WARM
FRONT LIFTS NORTH. THE AREA WILL BE ON THE PERIPHERY OF THE RIDGE
ONCE AGAIN FAVORING MORE CONVECTION...ESPECIALLY NORTH...THROUGH
FRIDAY. HEAVY RAINFALL AND GUSTY WINDS WILL BE THE MAIN THREATS WITH
THE STORMS THROUGH THE END OF THE WEEK. TEMPERATURES WILL RANGE FROM
THE LOWER 70S NEAR THE LAKE WEDNESDAY WITH A STEADY NORTHEAST
WIND...WITH UPPER 70S INLAND NORTH TO LOWER 80S SOUTH. EASTERLY
WINDS WILL KEEP SIMILAR TEMPS IN PLACE THURSDAY WITH WARMER READINGS
FRIDAY ALL THE WAY TO THE LAKE WITH THE FRONT MOVING NORTHWARD.
TEMPS MAY BE AFFECTED BY CONVECTION EACH DAY.
SATURDAY AND BEYOND...ACTIVE WEATHER CONTINUES THROUGH EARLY NEXT
WEEK AS THE CUTOFF TROUGH MOVES ACROSS THE AREA OVER THE WEEKEND
BRINGING CONTINUED SHOWER AND THUNDERSTORM ACTIVITY. ANOTHER UPPER
LOW IS FORECAST TO TRACK ACROSS SOUTHERN CANADA MONDAY/TUESDAY
BRINGING A COLD FRONT ACROSS THE AREA ALONG WITH MORE STORM CHANCES.
HIGHS SHOULD CONTINUE IN THE UPPER 70S AND LOWER 80S.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* SCT VCTS THROUGH 17Z. STRONGER STORMS MAY PRODUCE GUSTY WINDS IN
EXCESS OF 30 KT AND MVFR OR LOWER VSBYS.
* WIND SHIFT TO N WINDS ARND 8 KT ARND 16Z.
* LAKE BREEZE SHIFTING WINDS TO NE LESS THAN 10 KT ARND 20Z.
* CHANCE OF TSRA WED MORNING.
JEE
//DISCUSSION...UPDATED 12Z...
SCATTERED TSRA HAS DEVELOPED MAINLY EAST OF THE TERMINALS BUT
STILL SOME ACTIVITY ACROSS NORTHERN IL. CONFIDENCE REGARDING
DIRECT IMPACTS AT THE TERMINALS OVER THE NEXT FEW HOURS IS LOW
BUT WILL CONTINUE WITH TEMPO MENTION THRU 14Z...WHEN THIS ACTIVITY
SHOULD BE EAST AND SOUTHEAST OF THE TERMINALS. FOCUS THEN SHIFTS
TO LINE OF TSRA MOVING ACROSS EASTERN IOWA. MOST SHORT TERM/HI RES
GUIDANCE SHOWS THIS COMPLEX WEAKENING AS IT MOVES ACROSS NORTHWEST
IL LATER THIS MORNING. CONFIDENCE FOR TSRA REACHING RFD IS HIGH
ENOUGH TO INCLUDE MENTION THERE BUT FURTHER EAST HAVE OPTED FOR
SHRA AT DPA AND THEN DRY ORD/MDW/GYY. TRENDS WILL NEED TO BE
MONITORED IN THE NEXT FEW HOURS. IF THIS ACTIVITY HOLDS
TOGETHER...IT COULD ARRIVE INTO THE ORD/MDW AREA AROUND 17Z.
A WEAK COLD FRONT WILL MOVE SOUTH ACROSS THE TERMINALS THIS
MORNING...PERHAPS AIDED BY OUTFLOW FROM THUNDERSTORMS OVER EASTERN
IOWA. WINDS WILL SHIFT NORTHERLY BEHIND THE FRONT WITH PREVAILING
SPEEDS LIKELY UNDER 10KTS. WINDS REMAIN NORTH/NORTHEAST UNDER
10KTS THRU EARLY/MID AFTERNOON WHEN A LAKE BREEZE MAY MOVE ACROSS
THE CHICAGO AREA TERMINALS...TURNING WINDS MORE NORTHEASTERLY WITH
SPEEDS PERHAPS AROUND 10KTS...THOUGH CONFIDENCE ON SPEEDS IS LOW.
WIND DIRECTION WILL THEN REMAIN NORTHEAST FOR THE REMAINDER OF THE
PERIOD WITH SPEEDS UNDER 10KTS.
ANOTHER ROUND OF SHRA/TSRA IS POSSIBLE WEDNESDAY MORNING. TIMING
IS UNCERTAIN BUT CONFIDENCE OF TSRA NEARBY IS HIGH ENOUGH TO
INCLUDE PROB MENTION AND FOR NOW HAVE GONE WITH TIMING NEAR OR
JUST AFTER DAYBREAK. CMS
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE IN TSRA COVERAGE...MEDIUM-LOW CONFIDENCE IN A
TSRA MOVING OVER THE TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE WIND SPEEDS LESS THAN 10
KT...MEDIUM CONFIDENCE IN LAKE BREEZE TIMING.
* MEDIUM CONFIDENCE IN TSRA WED MORNING.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF TSRA.
* THURSDAY THROUGH MONDAY...CHANCE OF TSRA.
&&
.MARINE...
246 AM...LOW PRESSURE NEAR JAMES BAY WILL CONTINUE EAST ACROSS
NORTHERN QUEBEC TODAY AS A TRAILING COLD FRONT MOVES SOUTH ACROSS
LAKE MICHIGAN THIS MORNING. WEST/SOUTHWEST WINDS WILL SHIFT TO THE
NORTH BUT SPEEDS SHOULD REMAIN IN THE 10-15KT RANGE. HIGH PRESSURE
OVER THE DAKOTAS WILL MOVE EAST ACROSS THE LAKES REGION WEDNESDAY
INTO WEDNESDAY NIGHT. AS IT DOES...THE GRADIENT WILL TIGHTEN SOME
ON THE FAR SOUTH END OF THE LAKE...ALLOWING NORTH TO NORTHEAST
WINDS TO INCREASE INTO THE 10-20KT RANGE. THIS HIGH WILL MOVE EAST
THURSDAY WITH A WARM FRONT LIFTING BACK NORTH ACROSS THE LAKE
THURSDAY NIGHT...SHIFTING WINDS BACK SOUTHERLY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1046 AM CDT Tue Aug 26 2014
.UPDATE...
ISSUED AT 1038 AM CDT TUE AUG 26 2014
Front still to the northwest this morning and a series of
thunderstorms across the northern tier of the state. So far, only
a few showers have been triggered into ILX. Potential for showers
and thunderstorms still in place for Central Illinois through
today, as heat and high dwpts increase the instability ahead of
the front. Some minor updates to the hourly temperatures...but no
major updates at this time. Will likely be adjusting the forecast
into the afternoon as the front approaches...but at this point,
the updates will be minor.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 312 AM CDT TUE AUG 26 2014
One more hot and humid day is on tap for at least the southern half
of the KILX CWA, as heat index readings climb into the 105 to 110F
range during peak heating. The heat warning will continue from
Lincoln and south, with the heat advisory east to Champaign/Danville
through early evening.
Last evening some cooler air was pushed out from a line of storms
that clipped our north from Stark County to Champaign/Vermilion
counties and south along the Indiana border. That worked to lower
dew points across the north, which should help to keep the heat
indices a bit lower during the afternoon, but still hot in the
upper 90s.
Once again the high-res models are having a hard time with current
convection and are all over the board with respect to storm
development over the next 24 hours. When merged with the lower
resolution models, the general theme is for a line of storms to
eventually develop across our northern counties as a cold front
slowly moves south into our forecast area. A few storm cells
developing in eastern Iowa over the last hour has increased some
confidence that a few storms could affect our northwestern counties
by mid-morning, so will keep at least chance PoPs NW of Peoria this
morning. The daytime storms are projected to drift south as they
dissipate toward I-72 later this afternoon. The next complex of
storms is projected for later tonight, when a stronger MCS is
forecast to roll out of Iowa. Under that scenario, storms would
affect areas north of Peoria after 08z/2am CDT, where we have likely
PoPs.
There remains a high level of elevated instability, with plenty of
precipitable water, so any storms that can overcome the mid-level
warming could produce some very heavy rainfall and strong winds over
the next 24 hours.
&&
.LONG TERM...(Wednesday through Labor Day)
ISSUED AT 312 AM CDT TUE AUG 26 2014
Upper ridge will be breaking down on Wednesday as a wave moves
through the upper Great Lakes region. Still watching the deep trough
seen on water vapor imagery across the western U.S. this morning.
Last couple model runs had some reasonable agreement with tracking
this feature into the Plains by early Saturday, but have some
disagreements resolving the split flow over the central U.S. as a
trough digs over the Pacific Northwest. The ECMWF largely dampen out
the Plains wave, while the GFS keeps it somewhat intact and lifts it
into Wisconsin on Sunday, possibly due to some feedback issues. Have
leaned the holiday weekend forecast more toward the ECMWF as a
result.
In the nearer term, the 00Z models largely bring the front through
most of the forecast area by Wednesday evening, with the NAM
furthest north and the GEM/GFS furthest south. Best shower/storm
threat will be during the morning before the precipitation is
shunted into what`s left of the ridge. After that, focus shifts to
our northwest as the front lifts back northward in response to the
wave moving onto the Plains. Frequent MCS activity will lead to
potential flooding concerns across Iowa/Wisconsin, with mainly
scattered activity in our area from the remnants of said activity or
other development along the boundary.
Rather humid conditions expected to continue on Wednesday, until
drier air spreads in from a high pressure building into the Great
Lakes. However, the humidity will return on Thursday as the front
lifts back north. Temperatures across the southeast CWA may still
reach the lower 90s Wednesday and Thursday, but highs in the 80s
will prevail through the period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 655 AM CDT TUE AUG 26 2014
A cold front will progress into central IL this afternoon.
Scattered thunderstorms are expected near the front, especially
this afternoon. PIA and BMI could see a few showers and possibly
storms after 15z this morning. The high res models have varying
solutions, with the RAP showing a line of convection across
central IL already at 12z this morning, which is not occurring.
The HRRR holds off storms until 16z near PIA/BMI, with additional
storms behind the cold front this afternoon.
The lower resolution NAM/GFS/Canadian/ECMWF have varying
precipitation patterns over the next 24 hours as well. Overall,
will stick with afternoon storms near the cold front at all TAF
sites. There is some agreement that after midnight tonight,
an MCV will roll out of Iowa into NC Illinois, triggering the next
round of storms. Those would affect PIA and BMI mainly, based on
the expected storm track.
Winds will start out south-southwest ahead of the cold front. By
afternoon, northerly winds will develop behind the front
progressively from PIA to BMI to CMI. The frontal motion will slow
down by this evening as it stalls out over SPI/DEC. Winds at those
sites could just become variable for much of the night.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT this evening FOR ILZ042-
047>054-056-061>063-066>068-071>073.
HEAT ADVISORY until 7 PM CDT this evening FOR ILZ043>046-055-057.
&&
$$
UPDATE...HJS
SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
922 AM CDT TUE AUG 26 2014
.DISCUSSION...
328 AM CDT
SHOWER AND THUNDERSTORM CHANCES AND TIMING WILL BE THE MAIN FORECAST
CHALLENGE THROUGH THE PERIOD FOLLOWED BY TEMPS AS THEY MAY BE
INFLUENCED BY ROUNDS OF CONVECTION. WATER VAPOR IMAGERY SHOWS THE
UPPER WHICH CONTRIBUTED TO THE BREAKING DOWN OF THE PERSISTENT UPPER
RIDGE OVER THE AREA IS TRACKING NORTHEAST ACROSS JAMES BAY LEAVING
CORRIDOR OF FAIRLY ZONAL FLOW ACROSS THE UPPER MIDWEST AND GREAT
LAKES. ANOTHER UPPER LOW IS SLOWLY SPINNING SOUTHWARD ACROSS
NORTHERN CALIFORNIA AND NEVADA CUTTING OFF FROM A TROUGH AXIS TO THE
NORTH WHICH IS MOVING EAST ACROSS THE CANADIAN PRAIRIES. A RIDGE
AXIS IS PIVOTING EASTWARD OVER WESTERN CANADA AS AN UPPER TROUGH
MOVES EASTWARD ACROSS SOUTHERN ALASKA. AT THE SURFACE...LOW PRESSURE
IS OVER JAMES BAY WITH A COLD FRONT TRAILING IT ACROSS CENTRAL
WISCONSIN AND IOWA. ONE AREA OF HIGH PRESSURE IS STRETCHED UP AND
DOWN THE EASTERN SEABOARD WHILE ANOTHER HIGH IS OVER THE NORTHERN
PLAINS IN THE WAKE OF THE COLD FRONT.
TODAY...THE AFOREMENTIONED COLD FRONT TO THE NORTHWEST WILL BE
ENTERING THE CWA IN THE NEXT FEW HOURS BUT LOOKS TO GET HUNG UP NEAR
THE I-80 CORRIDOR FOR A TIME LATER THIS MORNING. CONVECTIVE TRENDS
ARE A CHALLENGE THIS MORNING WITH THE FRONT AND SEVERAL OTHER
FEATURES PRESENT TO KEEP SHOWERS AND THUNDERSTORMS GOING. EVENING
UPPER AIR ANALYSIS SHOWED AN UPPER JET CORE FROM SOUTHWEST MINNESOTA
TO JAMES BAY WHICH PLACES THE RIGHT ENTRANCE REGION OVER IOWA. THE
NOSE OF A LOW LEVEL JET IS AIMED INTO SOUTHEAST NEBRASKA BUT TURNS
WESTERLY ACROSS SOUTHERN IOWA. THIS HAS LED TO A DECENT DIFFERENTIAL
DIVERGENCE SET UP BETWEEN THE LOW LEVEL AND UPPER LEVEL JETS. IN
ADDITION...AN UPPER WAVE APPEARS TO BE TRACKING NORTHEAST ACROSS
NORTH CENTRAL KANSAS. ALL OF THIS IS LEADING TO VARYING DEGREES OF
CONVECTIVE DEVELOPMENT FROM EAST CENTRAL NEBRASKA/WEST CENTRAL
IOWA...WHERE THE COVERAGE IS EXTENSIVE...TO EASTERN IOWA AND NOW
JUST INTO NW ILLINOIS WHERE COVERAGE IS ISOLATED THUS FAR. 850-300
MB THICKNESS TAKES THIS ACTIVITY EASTWARD. HOW WELL THIS SUSTAINS
ITSELF IS IN QUESTION BUT GIVEN THAT THERE ARE SEVERAL LARGE SCALE
FACTORS DRIVING IT AND THERE IS A GOOD POOL OF INSTABILITY NEAR AND
AHEAD OF THE FRONT THERE IS GOOD REASON FOR IT TO CONTINUE. NOT TOO
MENTION THE TREND OF THE PAST SEVERAL DAYS HAS BEEN FOR MORNING
CONVECTION TO FESTER AND/OR SPIN OFF NEW CONVECTION MIDDAY ONWARD.
ISOLATED TO SCATTERED ACTIVITY WILL BEGIN TO AFFECT THE AREA IN THE
NEXT FEW HOURS WHILE THE MORE SOLID ACTIVITY OVER WEST CENTRAL IOWA
AND EAST CENTRAL NEBRASKA OR ACTIVITY SPUN OFF FROM IT WOULD
POTENTIALLY AFFECT THE AREA LATE MORNING/EARLY AFTERNOON. THIS
COMPLEX HAS BEEN ORGANIZING AND ACCELERATING EASTWARD TO SOME DEGREE
IN THE LAST HOUR OR SO. IN ADDITION...WITH THE FRONTAL BOUNDARY
LIKELY STILL IN THE SOUTHERN CWA THIS AFTERNOON IT MAY SERVE AS
FOCUS FOR NEW CONVECTION AS WELL. IT DOES APPEAR THAT POPS WILL
TAPER OFF ACROSS THE NORTH DURING THE LATE AFTERNOON. TORRENTIAL
DOWNPOURS AND LOCALIZED FLOODING WILL BE THE MAIN THREAT WITH ANY
STORMS ONCE AGAIN...WITH GUSTY STRAIGHT LINE WINDS AND ADDITIONAL
THREAT. MID LEVEL AIR WILL STILL BE QUITE WARM WITH H85 TEMPS NEAR
+20C BUT LOW LEVEL WINDS WILL TURN NORTHERLY AND EVEN NORTHEASTERLY
NEAR LAKE MICHIGAN. EXPECT HIGHS IN THE UPPER 80S FAR SOUTH AND NEAR
80 NEAR THE LAKE AND FAR NORTHERN INLAND AREAS...WITH LOW TO MID 80S
IN BETWEEN. CONVECTION COULD ONCE AGAIN HAVE AN IMPACT ON
HIGHS...ESPECIALLY SOUTH IF ACTIVITY CONTINUES INTO THE AFTERNOON
GIVEN THE BETTER PROXIMITY TO THE FRONTAL BOUNDARY.
TONIGHT THROUGH FRIDAY...CONVECTIVE CHANCES REMAIN A CHALLENGE THIS
PERIOD. THE SURFACE FRONT WILL BE TO THE SOUTH OF THE AREA BUT THE
MAIN MID LEVEL THERMAL GRADIENT WILL BE OVERHEAD AND EVEN NORTH OF
THE AREA. THE LOW AMPLITUDE UPPER TROUGH CURRENTLY WORKING INTO THE
CANADIAN PRAIRIES IN THE MAIN NORTHERN STREAM OF FLOW WILL BE
PASSING TO THE NORTH SUPPLYING MODEST HEIGHT FALLS TO THE LOCAL AREA
TONIGHT AND WEDNESDAY MORNING. THE RIGHT ENTRANCE OF THE UPPER JET
WILL ALSO BE PASSING OVER THE AREA. GUIDANCE SUGGESTS THAT THERE
WILL BE A WAVE EJECTING FROM THE CUTOFF UPPER TROUGH ACROSS THE
CENTRAL PLAINS AS WELL. IT APPEARS THAT CONVECTION WILL BE
DEVELOPING TO THE WEST TONIGHT THEN TRACK EASTWARD IN CONJUNCTION
WITH THE SYNOPTIC FEATURES. THIS SHOULD RESULT IN BEST CHANCES FOR
PRECIP LATER TONIGHT AND WEDNESDAY MORNING....THOUGH HAVE AN INKLING
THIS MAY BE A BIT FAST. THIS MAY BE ANOTHER SITUATION WHERE ACTIVITY
WILL BE DECAYING IN THE MORNING AS IS GETS CLOSER TO THE AREA. MUCH
OF THE AREA COULD SEE PRECIP BUT THE BEST FOCUS MAY BE ACROSS THE
SOUTH IN CLOSER PROXIMITY TO THE FRONT. THE CUTOFF UPPER LOW WILL BE
SLOWLY BUT STEADILY MOVING EASTWARD FORCING MODEST RIDGING INTO THE
AREA GOING INTO THURSDAY. THIS WILL BRING ANOTHER PUSH OF WARM
ADVECTION ACROSS THE CENTRAL U.S. WEDNESDAY NIGHT AND DRIVE THE
FRONTAL BOUNDARY NORTH AS A WARM FRONT. AT THIS POINT THE BULK OF
THE CONVECTION LOOKS TO BE TO THE WEST WEDNESDAY NIGHT WITH IT THEN
AFFECTING THE CWA THURSDAY...WITH BEST CHANCES NORTH AS THE WARM
FRONT LIFTS NORTH. THE AREA WILL BE ON THE PERIPHERY OF THE RIDGE
ONCE AGAIN FAVORING MORE CONVECTION...ESPECIALLY NORTH...THROUGH
FRIDAY. HEAVY RAINFALL AND GUSTY WINDS WILL BE THE MAIN THREATS WITH
THE STORMS THROUGH THE END OF THE WEEK. TEMPERATURES WILL RANGE FROM
THE LOWER 70S NEAR THE LAKE WEDNESDAY WITH A STEADY NORTHEAST
WIND...WITH UPPER 70S INLAND NORTH TO LOWER 80S SOUTH. EASTERLY
WINDS WILL KEEP SIMILAR TEMPS IN PLACE THURSDAY WITH WARMER READINGS
FRIDAY ALL THE WAY TO THE LAKE WITH THE FRONT MOVING NORTHWARD.
TEMPS MAY BE AFFECTED BY CONVECTION EACH DAY.
SATURDAY AND BEYOND...ACTIVE WEATHER CONTINUES THROUGH EARLY NEXT
WEEK AS THE CUTOFF TROUGH MOVES ACROSS THE AREA OVER THE WEEKEND
BRINGING CONTINUED SHOWER AND THUNDERSTORM ACTIVITY. ANOTHER UPPER
LOW IS FORECAST TO TRACK ACROSS SOUTHERN CANADA MONDAY/TUESDAY
BRINGING A COLD FRONT ACROSS THE AREA ALONG WITH MORE STORM CHANCES.
HIGHS SHOULD CONTINUE IN THE UPPER 70S AND LOWER 80S.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* SCT VCTS THROUGH 17Z. STRONGER STORMS MAY PRODUCE GUSTY WINDS IN
EXCESS OF 30 KT AND MVFR OR LOWER VSBYS.
* WIND SHIFT TO N WINDS ARND 8 KT ARND 16Z.
* LAKE BREEZE SHIFTING WINDS TO NE LESS THAN 10 KT ARND 20Z.
* CHANCE OF TSRA WED MORNING.
JEE
//DISCUSSION...UPDATED 12Z...
SCATTERED TSRA HAS DEVELOPED MAINLY EAST OF THE TERMINALS BUT
STILL SOME ACTIVITY ACROSS NORTHERN IL. CONFIDENCE REGARDING
DIRECT IMPACTS AT THE TERMINALS OVER THE NEXT FEW HOURS IS LOW
BUT WILL CONTINUE WITH TEMPO MENTION THRU 14Z...WHEN THIS ACTIVITY
SHOULD BE EAST AND SOUTHEAST OF THE TERMINALS. FOCUS THEN SHIFTS
TO LINE OF TSRA MOVING ACROSS EASTERN IOWA. MOST SHORT TERM/HI RES
GUIDANCE SHOWS THIS COMPLEX WEAKENING AS IT MOVES ACROSS NORTHWEST
IL LATER THIS MORNING. CONFIDENCE FOR TSRA REACHING RFD IS HIGH
ENOUGH TO INCLUDE MENTION THERE BUT FURTHER EAST HAVE OPTED FOR
SHRA AT DPA AND THEN DRY ORD/MDW/GYY. TRENDS WILL NEED TO BE
MONITORED IN THE NEXT FEW HOURS. IF THIS ACTIVITY HOLDS
TOGETHER...IT COULD ARRIVE INTO THE ORD/MDW AREA AROUND 17Z.
A WEAK COLD FRONT WILL MOVE SOUTH ACROSS THE TERMINALS THIS
MORNING...PERHAPS AIDED BY OUTFLOW FROM THUNDERSTORMS OVER EASTERN
IOWA. WINDS WILL SHIFT NORTHERLY BEHIND THE FRONT WITH PREVAILING
SPEEDS LIKELY UNDER 10KTS. WINDS REMAIN NORTH/NORTHEAST UNDER
10KTS THRU EARLY/MID AFTERNOON WHEN A LAKE BREEZE MAY MOVE ACROSS
THE CHICAGO AREA TERMINALS...TURNING WINDS MORE NORTHEASTERLY WITH
SPEEDS PERHAPS AROUND 10KTS...THOUGH CONFIDENCE ON SPEEDS IS LOW.
WIND DIRECTION WILL THEN REMAIN NORTHEAST FOR THE REMAINDER OF THE
PERIOD WITH SPEEDS UNDER 10KTS.
ANOTHER ROUND OF SHRA/TSRA IS POSSIBLE WEDNESDAY MORNING. TIMING
IS UNCERTAIN BUT CONFIDENCE OF TSRA NEARBY IS HIGH ENOUGH TO
INCLUDE PROB MENTION AND FOR NOW HAVE GONE WITH TIMING NEAR OR
JUST AFTER DAYBREAK. CMS
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE IN TSRA COVERAGE...MEDIUM-LOW CONFIDENCE IN A
TSRA MOVING OVER THE TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE WIND SPEEDS LESS THAN 10
KT...MEDIUM CONFIDENCE IN LAKE BREEZE TIMING.
* MEDIUM CONFIDENCE IN TSRA WED MORNING.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...SLIGHT CHANCE OF TSRA.
* THURSDAY THROUGH MONDAY...CHANCE OF TSRA.
&&
.MARINE...
246 AM...LOW PRESSURE NEAR JAMES BAY WILL CONTINUE EAST ACROSS
NORTHERN QUEBEC TODAY AS A TRAILING COLD FRONT MOVES SOUTH ACROSS
LAKE MICHIGAN THIS MORNING. WEST/SOUTHWEST WINDS WILL SHIFT TO THE
NORTH BUT SPEEDS SHOULD REMAIN IN THE 10-15KT RANGE. HIGH PRESSURE
OVER THE DAKOTAS WILL MOVE EAST ACROSS THE LAKES REGION WEDNESDAY
INTO WEDNESDAY NIGHT. AS IT DOES...THE GRADIENT WILL TIGHTEN SOME
ON THE FAR SOUTH END OF THE LAKE...ALLOWING NORTH TO NORTHEAST
WINDS TO INCREASE INTO THE 10-20KT RANGE. THIS HIGH WILL MOVE EAST
THURSDAY WITH A WARM FRONT LIFTING BACK NORTH ACROSS THE LAKE
THURSDAY NIGHT...SHIFTING WINDS BACK SOUTHERLY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
655 AM CDT Tue Aug 26 2014
.SHORT TERM...(Today and tonight)
ISSUED AT 312 AM CDT TUE AUG 26 2014
One more hot and humid day is on tap for at least the southern half
of the KILX CWA, as heat index readings climb into the 105 to 110F
range during peak heating. The heat warning will continue from
Lincoln and south, with the heat advisory east to Champaign/Danville
through early evening.
Last evening some cooler air was pushed out from a line of storms
that clipped our north from Stark County to Champaign/Vermilion
counties and south along the Indiana border. That worked to lower
dew points across the north, which should help to keep the heat
indices a bit lower during the afternoon, but still hot in the
upper 90s.
Once again the high-res models are having a hard time with current
convection and are all over the board with respect to storm
development over the next 24 hours. When merged with the lower
resolution models, the general theme is for a line of storms to
eventually develop across our northern counties as a cold front
slowly moves south into our forecast area. A few storm cells
developing in eastern Iowa over the last hour has increased some
confidence that a few storms could affect our northwestern counties
by mid-morning, so will keep at least chance PoPs NW of Peoria this
morning. The daytime storms are projected to drift south as they
dissipate toward I-72 later this afternoon. The next complex of
storms is projected for later tonight, when a stronger MCS is
forecast to roll out of Iowa. Under that scenario, storms would
affect areas north of Peoria after 08z/2am CDT, where we have likely
PoPs.
There remains a high level of elevated instability, with plenty of
precipitable water, so any storms that can overcome the mid-level
warming could produce some very heavy rainfall and strong winds over
the next 24 hours.
&&
.LONG TERM...(Wednesday through Labor Day)
ISSUED AT 312 AM CDT TUE AUG 26 2014
Upper ridge will be breaking down on Wednesday as a wave moves
through the upper Great Lakes region. Still watching the deep trough
seen on water vapor imagery across the western U.S. this morning.
Last couple model runs had some reasonable agreement with tracking
this feature into the Plains by early Saturday, but have some
disagreements resolving the split flow over the central U.S. as a
trough digs over the Pacific Northwest. The ECMWF largely dampen out
the Plains wave, while the GFS keeps it somewhat intact and lifts it
into Wisconsin on Sunday, possibly due to some feedback issues. Have
leaned the holiday weekend forecast more toward the ECMWF as a
result.
In the nearer term, the 00Z models largely bring the front through
most of the forecast area by Wednesday evening, with the NAM
furthest north and the GEM/GFS furthest south. Best shower/storm
threat will be during the morning before the precipitation is
shunted into what`s left of the ridge. After that, focus shifts to
our northwest as the front lifts back northward in response to the
wave moving onto the Plains. Frequent MCS activity will lead to
potential flooding concerns across Iowa/Wisconsin, with mainly
scattered activity in our area from the remnants of said activity or
other development along the boundary.
Rather humid conditions expected to continue on Wednesday, until
drier air spreads in from a high pressure building into the Great
Lakes. However, the humidity will return on Thursday as the front
lifts back north. Temperatures across the southeast CWA may still
reach the lower 90s Wednesday and Thursday, but highs in the 80s
will prevail through the period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 655 AM CDT TUE AUG 26 2014
A cold front will progress into central IL this afternoon.
Scattered thunderstorms are expected near the front, especially
this afternoon. PIA and BMI could see a few showers and possibly
storms after 15z this morning. The high res models have varying
solutions, with the RAP showing a line of convection across
central IL already at 12z this morning, which is not occurring.
The HRRR holds off storms until 16z near PIA/BMI, with additional
storms behind the cold front this afternoon.
The lower resolution NAM/GFS/Canadian/ECMWF have varying
precipitation patterns over the next 24 hours as well. Overall,
will stick with afternoon storms near the cold front at all TAF
sites. There is some agreement that after midnight tonight,
an MCV will roll out of Iowa into NC Illinois, triggering the next
round of storms. Those would affect PIA and BMI mainly, based on
the expected storm track.
Winds will start out south-southwest ahead of the cold front. By
afternoon, northerly winds will develop behind the front
progressively from PIA to BMI to CMI. The frontal motion will slow
down by this evening as it stalls out over SPI/DEC. Winds at those
sites could just become variable for much of the night.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT this evening FOR ILZ042-
047>054-056-061>063-066>068-071>073.
HEAT ADVISORY until 7 PM CDT this evening FOR ILZ043>046-055-057.
&&
$$
SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1223 AM CDT TUE AUG 26 2014
.DISCUSSION...
710 PM CDT
THE FORECAST UPDATED TO REFLECT CURRENT STORM TRENDS AS WELL AS
TO ADD AREAS OF FOG TONIGHT. DO ENVISION CANCELLING THE SEVERE
THUNDERSTORM WATCH FOR THE REMAINDER OF THE CWA BY 8 PM.
AN AREA OF LOOSELY ORGANIZED STORMS CONTINUES TO PROPAGATE SLOWLY
SOUTHEAST WITH OCCASIONAL FINGERS OF SLIGHTLY BETTER WIND
SIGNATURES ON RADAR. VERY EFFICIENT RAINFALL WILL REMAIN THE
PRIMARY HAZARD WITH THESE AS THEY CROSS THROUGH SOUTHERN IROQUOIS
AND BENTON COUNTIES. 00Z RAOB AND VAD WIND PROFILE FROM ILX
INDICATE SOUTHWEST FLOW AT 15-20 KT BETWEEN 3000-6000 FT...ENOUGH
TO HOLD UP THE OUTFLOW BOUNDARY NEAR THE I-74 CORRIDOR FROM NEAR
PEORIA TO BLOOMINGTON NORMAL BASED ON RADAR TRENDS. THIS FLOW DOES
NOT LOOK STRONG ENOUGH TO DEVELOP MUCH CONVECTION NORTH OF
THAT...SO OVERALL EXPECTING A QUIET EVENING FOR MUCH OF THE
FORECAST AREA.
WATER VAPOR AND LATE DAY VISIBLE SATELLITE INDICATE A SHEARED
SHORT WAVE MOVING EAST-NORTHEAST NEAR DES MOINES. WITH MINIMAL
CONVERGENCE IN THE 800-900MB LAYER /BASICALLY AT THE BASE OF THE
ELEVATED INSTABILITY/...IT IS DIFFICULT TO SAY WHAT THIS FEATURE
WILL DO IN TERMS OF SHOWERS OR CONVECTION LATE TONIGHT. HIGH
RESOLUTION GUIDANCE DOES VARY GREATLY...HOWEVER USING A SHORT
RANGE ENSEMBLE APPROACH INDICATES OVERLAP ACROSS NORTHWEST INTO
NORTH CENTRAL IL LATE. FOR NOW DO CONTINUE THE CHANCE OF THUNDER
OVERNIGHT...WITH SOMEWHAT HIGHER POPS IN THAT AREA.
BECAUSE OF THE RAIN-COOLED MOIST AIR GOING INTO DARK...AREAS OF
FOG SEEM MORE PROBABLE BY AFTER MIDNIGHT...SOME OF WHICH MAY BE
DENSE GIVEN SUCH LOW T/TD SPREADS AT PRESENT.
MTF
//PREV DISCUSSION...
325 PM CDT
SHORT TERM...THROUGH EARLY TUESDAY MORNING...
FOR THE REMAINDER OF THE AFTERNOON...MAIN FOCUS WILL CONTINUE TO BE
TWO LINES OF THUNDERSTORMS...ONE MOVING THROUGH NWRN IL AND ANOTHER
MOVING THROUGH NWRN IN AND ECNTRL IL. THESE LINES ARE PRODUCING
STRONG TO OCNLY SVR TS...WITH THE PRIMARY THREAT BEING WIND GUSTS
TO 60 MPH AND TORRENTIAL DOWNPOURS. THE TREND WITH TIME SHOULD BE
FOR THE LINE OVER NWRN IL TO BEGIN TO WEAKEN AS IT MOVES INTO AN
AIRMASS OVER NERN IL WHICH HAS BEEN WORKED OVER BY EARLIER
CONVECTION. THE LINE ACROSS NWRN IN INTO ECNTRL IL SHOULD MAINTAIN
SOME STRENGTH AS IT CONTINUES TO PUSH SEWD. LATEST RADAR IMAGERY
SHOWS A DISTINCT OUTFLOW BOUNDARY EXTENDING WEST FROM KANKAKEE TO
PERU WHICH COULD YET BE THE FOCUS FOR SOME ADDITIONAL THUNDERSTORM
DEVELOPMENT INTO THE EARLY EVENING HOURS. THUNDERSTORMS HAVE HAD A
HISTORY OF PRODUCING IN EXCESS OF 1 INCH IN 30 MINUTES...BUT SINCE
THEY HAVE BEEN PROGRESSIVE...SIGNIFICANT WIDESPREAD FLOODING IS NOT
ANTICIPATED...THOUGH LOCALLY HEAVY RAINFALL COULD PRODUCE URBAN ANS
SMALL STREAM TYPE FLOODING. EXPECT THAT THE POTENTIAL FOR ORGANIZED
THUNDERSTORMS MAY CONTINUE INTO EARLY THIS EVENING AS WELL...WITH
SOME POTENTIAL FOR A FORWARD-PROPAGATING MCS ACROSS MAINLY THE
SOUTHERN HALF OF THE FORECAST AREA. THIS WOULD BE MAINLY CAPABLE
OF WIND. AS THE THUNDERSTORM ACTIVITY DIMINISHES LATER THIS
EVENING...PATCHY FOG AND WIDESPREAD MISTY/MURKY CONDITIONS WILL
SET UP. WHILE WIDESPREAD DENSE FOG IS NOT LIKELY DUE TO PERSISTENT
DEBRIS CLOUD FROM EARLIER CONVECTION...A VERY MOIST ENVIRONMENT
WILL REMAIN IN PLACE...AND COMBINED WITH LIGHT WINDS CONDITIONS
WILL REMAIN MUGGY OVERNIGHT.
THE TEMPERATURE FORECAST FOR TODAY WAS DISRUPTED BY THE THUNDERSTORMS
AND EXTENSIVE CLOUD COVER OVER AREAS IMPACTED BY THE THUNDERSTORMS.
HOWEVER...LOCATIONS SOUTH OF A LINE FROM MIDWAY AIRPORT TO PERU
STILL SAW MAX HEAT INDICES IN EXCESS OF 100F WHILE LOCATIONS SOUTH
OF THE ILLINOIS/KANKAKEE RIVERS SAW HEAT INDICES APPROACH OR SLIGHTLY
EXCEED 110F. TEMPERATURES AND DEWPOINTS SHOULD REMAIN IN THE LOWER
TO MIDDLE 70S OVERNIGHT AS THERE WILL BE NO SGFNT CHANGE IN
AIRMASS. WITH OLD OUTFLOW BOUNDARIES HANGING AROUND THE AREA
OVERNIGHT...THERE WILL STILL BE SOME LOW CHANCES FOR ADDITIONAL
SHOWERS OR THUNDERSTORMS AS A WEAK COLD FRONT MOVES DOWN THE LAKE
AND INTO THE WARM...HUMID ENVIRONMENT.
KREIN
LONG TERM...TUESDAY THROUGH MONDAY...
TUESDAY AND WEDNESDAY...
THE MAIN CHANGE TO THE FORECAST DURING THIS PERIOD WAS TO SHIFT
THE HIGHER CHANCES FOR STORMS SOUTH AS THE FRONTAL BOUNDARY
ITSELF LOOKS TO BE FURTHER SOUTH THAN EARLIER FORECAST...LIKELY
HELPED BY EPISODES OF CONVECTION SUCH AS THIS AFTERNOON. BECAUSE
OF THIS...CHANCES OF STORMS IN THIS PERIOD LOOK TO BE GREATER IN
THE SOUTHERN FORECAST AREA THAN THE NORTH. LAKE ADJACENT AREAS
ALSO LOOK TO BE INFLUENCED BY LAKE AIR ON TUESDAY...POSSIBLY EVEN
BY MORNING. BECAUSE OF THAT HAVE ADJUSTED TEMPERATURES DOWNWARD ON
TUESDAY...WITH THE POSSIBILITY OF 90 NOW BEING HARBORED ONLY TO THE
FAR SOUTH...ALTHOUGH LIKE TODAY IF CONVECTION OCCURS THAT CAN
GREATLY DISRUPT THINGS. LOWER 80S LOOK MORE LIKELY NORTH WITH
UPPER 70S NEAR THE LAKE SHORE.
THERE COULD BE ONGOING ELEVATED STORM ACTIVITY FROM IA INTO
NORTHWESTERN/WESTERN IL AT DAYBREAK TUESDAY MOVING EASTWARD...THOUGH
THE DEGREE OF COVERAGE IS UNCERTAIN. MUCH LIKE TODAY...IF THERE IS
ENOUGH ACTIVITY IT COULD JUST CONTINUE TO FESTER EAST-SOUTHEAST INTO
THE ILLINOIS FORECAST AREA AND THEN FEED ON THE INSTABILITY IN THE
FAR SOUTHEAST PART OF THE AREA. EVEN IF THAT WERE NOT TO PAN
OUT...SCATTERED DEVELOPMENT OF STORMS LOOKS FAVORED IN THE AFTERNOON
ALONG THE BOUNDARY WHICH SHOULD BE DRAPED FROM WEST-TO-EAST NEAR
INTERSTATE 80. ANY THUNDERSTORM ACTIVITY WILL BE SIMILAR TO MUCH IN
THE PAST WEEK...POSSESSING HEAVY RAIN POTENTIAL AND ISOLATED GUSTY
WIND CONCERNS.
CHANCES FOR STORMS CONTINUE WEDNESDAY...MAINLY SOUTH...BEFORE 850MB
FLOW TURNS BRIEFLY MORE NORTHWESTERLY WEDNESDAY NIGHT.
THURSDAY INTO THE WEEKEND...
THE BOUNDARY REMAINS FORECAST TO RETURN NORTHWARD AS A WARM
FRONT...POSSIBLY ON THURSDAY...IN RESPONSE TO AN UPPER LOW MOVING
EAST FROM THE CENTRAL ROCKIES. A SURFACE LOW AHEAD OF THIS IS
FORECAST TO LIFT NORTHEAST...BUT OVERALL THIS LOOKS TO BE SLOW GIVEN
THE UPPER LEVEL FEATURE IS CUTOFF. TAPPING BACK INTO THE MOIST AIR
MASS THAT WE ARE PRESENTLY IN...IT WOULD APPEAR SHOWER AND STORM
CHANCES WOULD SPREAD BACK NORTHWARD ACROSS THE AREA AND LAST THROUGH
MUCH OF THIS TIME...ALTHOUGH MOST FAVORED AS WE GET INTO THE
STRONGER LOW LEVEL JET/MOISTURE TRANSPORT...WHICH IS DIFFICULT TO
TIME AT THIS POINT. THE TEMPERATURE FORECAST IS LOW
CONFIDENCE...WITH HIGHS SYNOPTICALLY FAVORED IN THE 80S...ALTHOUGH
CONVECTIVE AND/OR LAKE COOLING POSSIBLE EVERY DAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SHRA/TSRA PREDAWN THRU MID MORNING.
* POSSIBLE MVFR CIGS THIS MORNING.
* WIND SHIFT TO NORTH MID MORNING...THEN NORTHEAST TO 10KT EARLY
AFTERNOON. CMS
//DISCUSSION...UPDATED 06Z...
ISOLATED CONVECTION FIRING OVER NORTH CENTRAL IOWA IS EXPECTED TO
CONTINUE AND SPREAD EAST THROUGH THE OVERNIGHT HOURS. ADDITIONAL
CONVECTION COULD DEVELOP RIGHT OVER THE TERMINALS IN THE 09Z-11Z
TIME FRAME. THUS NO CHANGES TO CURRENT SHRA/VCTS MENTION OR TIMING
THOUGH TWEAKS MAY BE NEEDED AS TRENDS EMERGE INCLUDING THE
POTENTIAL FOR MORE THUNDER MENTION. THIS ACTIVITY IS THEN EXPECTED
TO MOVE SOUTHEAST OF THE AREA BY MID/LATE MORNING WITH ISOLATED
ACTIVITY POSSIBLE THIS AFTERNOON. ADDITIONAL SHRA/TSRA WILL BE
POSSIBLE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING BUT IF IT WERE
TO OCCUR...PROBABLY SIMILAR TIMING TO THIS MORNING 09Z OR LATER
AND WILL TAKE A CLOSER LOOK FOR POSSIBLE MENTION WITH THE 12Z TAFS
LATER THIS MORNING.
MVFR CIGS/VIS OR BRIEF IFR WILL BE POSSIBLE WITH ANY SHRA/TSRA.
OTHERWISE...A LOW VFR DECK 3-5KFT CONTINUES TO EXPAND ACROSS THE
AREA. THIS MAY LOWER INTO MVFR BY MORNING BUT CONFIDENCE TO
INCLUDE ANY PREVAILING MVFR CIGS IS LOW.
A COLD FRONT WILL CONTINUE TO MOVE SOUTH ACROSS THE AREA THIS
MORNING. LIGHT SOUTHERLY WINDS WILL TURN WESTERLY BY DAYBREAK AND
THEN SHIFT TO THE NORTH AS THE FRONT PUSHES THROUGH. WIND
DIRECTION AFTER FROPA IS A BIT UNCERTAIN AND MAY SHIFT BACK TO
THE NORTHWEST BEFORE A LAKE BREEZE MOVES ACROSS NORTHEAST IL
SHIFTING WINDS TO THE NORTHEAST. SPEEDS OUTSIDE OF ANY
CONVECTIVE/OUTFLOW ACTIVITY SHOULD REMAIN UNDER 10KTS. HOWEVER
SPEEDS WITH THE FRONT COULD BE IN THE 10-15KT RANGE WITH
PREVAILING 10KTS POSSIBLE WITH AND BEHIND THE LAKE BREEZE. CMS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM FOR SHRA/TSRA THIS MORNING.
* MEDIUM FOR WINDS THRU THE PERIOD.
* LOW FOR MVFR CIGS THIS MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...SLIGHT CHANCE OF TSRA.
THURSDAY...CHANCE OF TSRA.
FRIDAY...CHANCE OF TSRA.
SATURDAY...CHANCE OF TSRA.
SUNDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
315 PM CDT
SCATTERED STORMS THIS AFTERNOON HAVE DISRUPTED THE WINDS SOME
ACROSS THE FAR SOUTHERN PART OF LAKE MICHIGAN.
OTHERWISE...SOUTHERLY FLOW IS ANTICIPATED MUCH OF TONIGHT ACROSS
THE LAKE. DEW POINTS ARE NOT AS HIGH AS THEY HAVE BEEN BUT STILL
NEAR OR AT THE WATER TEMPERATURE...THUS POTENTIALLY LEADING TO
SOME PATCHY FOG. A COLD FRONT WILL MOVE ACROSS THE LAKE LATE
TONIGHT INTO TUESDAY MORNING...TURNING WINDS NORTHERLY. EVENTUALLY
THIS BOUNDARY WILL SHIFT BACK NORTH ACROSS THE LAKE MOST LIKELY ON
THURSDAY OR THURSDAY NIGHT. SOUTHERLY WINDS WILL THEN BE SEEN OVER
THE LAKE BEFORE LOW PRESSURE PASSES NEAR THE NORTHERN PART OF THE
LAKE SOMETIME EARLY THIS WEEKEND.
MTF
&&
.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
NATIONAL WEATHER SERVICE LINCOLN IL
1105 PM CDT Mon Aug 25 2014
.UPDATE...
ISSUED AT 822 PM CDT MON AUG 25 2014
Storms continue to slowly diminish early this evening and expect
that trend to continue over the next few hours as we lose daytime
heating and the storms track further south into the upper ridge.
Hi-res short term models providing mixed signals as to when
additional thunderstorms develop/move into our area late tonight
as a cold front edges slowly into western Illinois by morning.
Not very confident on any one solution at this point but it appears
the low level jet and 850 mb moisture convergence will be more
supportive of storms developing over Iowa late tonight and then
track into our west during the early morning hours. Series of
shortwaves expected to slowly break down the upper level ridge
and drag a frontal boundary south across our area early this
week, before the front heads back into our area late in the week
and into next week providing daily chances for showers and storms.
One more day of high heat and humidity levels on Tuesday before we
see a gradual downward trend in temps for the remainder of the week.
Zones have already been updated to reflect the cancellation of the
watch and timing trends with the showers and storms over east
central Illinois.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 312 PM CDT MON AUG 25 2014
Hot and very humid conditions are the rule across central Illinois
this afternoon, with 19z/2pm temperatures in the lower to middle 90s
across the board. Further north, clusters of thunderstorms have
developed along outflow boundaries from eastern Iowa across
northern Illinois. This convection is generally tracking eastward,
with a slight southeastward drift. High-res models are once again
handling the convection quite poorly, with the 2-hr HRRR forecast
completely missing the storms currently ongoing south of Chicago.
The Chicago storm complex will continue developing E/SE into
northwest Indiana over the next couple of hours. Meanwhile, we will
have to keep an eye on additional storms just north of Moline.
These cells will likely track E/SE along an outflow boundary evident
on satellite/radar imagery and should remain just north of the KILX
CWA. Have included a slight chance PoP along/northeast of a Henry
to Danville late this afternoon into the early evening in case they
develop a bit further southward.
A cold front currently analyzed across central Iowa will gradually
push eastward over the next 12 to 24 hours, reaching the northern
KILX CWA by Tuesday morning. Many of the 12z models show little or
no convection with the boundary overnight, but have included low
chance PoPs along/northwest of a Rushville to Bloomington line as
the front encounters a very moist airmass. Aside from any scattered
convection that may develop, the potential for fog will once again
be an issue overnight. Light/variable winds along with dewpoint
pooling along the boundary will favor fog, but increased mid/high
clouds may tend to mitigate it somewhat. Based on an unchanged
airmass and persistence from the past several nights, have included
patchy fog in the forecast after midnight.
Any fog will dissipate early Tuesday morning, followed by partly to
mostly sunny conditions across the southern half of the CWA.
Further north in closer proximity to the nearly stationary frontal
boundary, mostly cloudy skies and scattered convection will keep
temps slightly cooler than they have been recently. High temps on
Tuesday will range from the upper 80s north to the middle 90s
along/south of I-70. Due to the slightly cooler temps, heat index
readings across the north may not reach advisory criteria. May need
to drop the advisory for the Peoria area northward, as heat index
values will likely remain in the 95 to 100 degree range on Tuesday.
&&
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 312 PM CDT MON AUG 25 2014
A frontal boundary will become somewhat stationary over the area and
is forecast to remain there through the rest of the week and into
the weekend. This will become the focus for thunderstorms throughout
the period. Thunderstorms will not be continuous throughout the
period, but trying to time when the dry, or drier, periods is going
to be is the main forecast challenge. Due to the difficulty of
timing the precip periods and the dry periods during the medium and
long ranges of the forecast, best to just have chance pcpn through
the period over the whole area. Will have likely pops in the north
third of the CWA for Tue night, but remainder of the forecast will
just be chance across the area.
With the frontal boundary getting into the area, relatively cooler
air will advect into the area. Temperatures will gradually drop back
to around normal, which is middle to upper 80s, by the weekend.
However, with all the moisture forecasted over the area, muggy/humid
conditions will continue through the period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1100 PM CDT MON AUG 25 2014
Little change from previous discussion with the main concern
overnight being from lower vsbys due to fog and the threat
for more showers and storms, especially across the west and
northwest. Outflow boundary from this afternoon`s storms has
shifted well south of the forecast area this evening with an
east to southeast component to the surface winds thanks to a
meso-high that developed along the rear of the thundertorm
complex. What affect this outflow boundary will have on our
fog chances is not clear as a few nights ago we saw the same
thing happen during the late afternoon/early evening hours
with very little in the way of fog due to somewhat lower dew
points brought in with the outflow boundary. However, with
the rain we received with the storms, the low levels of the
atmosphere are saturated so any decrease in wind speeds overnight
should lead to at least patchy fog, which should lift across the
area by 13z.
A cool front will then push across the area during the day Tuesday
bringing a switch in winds and the threat for additional showers
and storms, which may push into our west as early as the 12z-15z
time frame. Outside any lower vsbys in fog early in the morning, it
still appears we should see mainly VFR conditions during the day.
Surface winds will be turning more into the southeast and then south
overnight with speeds of less than 10kts. Winds should then become
light northerly during the morning across the west and over the
east in the afternoon with speeds of 5 to 10 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT Tuesday FOR ILZ042-047>054-
056-061>063-066>068-071>073.
HEAT ADVISORY until 7 PM CDT Tuesday FOR ILZ043>046-055-057.
&&
$$
UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...AUTEN
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS DES MOINES IA
943 PM CDT WED AUG 27 2014
.UPDATE...
ISSUED AT 939 PM CDT WED AUG 27 2014
NO CHANGES TO EXISTING FLASH FLOOD WATCH HEADLINE. CURRENT NE/KS
MCS UPSTREAM IS EMBEDDED WITHIN A BROAD AREA OF WEAK/MODERATE
KINEMATIC AND THERMODYNAMIC FORCING AHEAD OF ROCKIES LONG WAVE
TROUGH IN AIRMASS VERY FAVORABLE FOR HEAVY EFFICIENT RAINFALL.
STRONGEST CONVECTION COINCIDES NICELY WITH 01Z RAP PRECIP
POTENTIAL PLACEMENT MAX AND THIS CROSSES MO RIVER INTO WRN
FORECAST AREA 09-12Z WITH MEAN WIND...THUS SLOWED POP ADVANCEMENT
SOMEWHAT IN EVENING UPDATE. 1-2KM MOISTURE FLOW AND ASSOCIATED
TRANSPORT IS NOT OVERLY STRONG...BUT VEERS INTO WRN IA BY
DAYBREAK. WITH PWS STILL IN EXCESS OF 2 INCHES...K INDICES AROUND
40...AND WARM CLOUD DEPTHS 4.2KM...ANY STRONGER CONVECTION COULD
CERTAINLY STILL PRODUCE EXCESSIVE RAINS.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 345 PM CDT WED AUG 27 2014
TIMING AND LOCATION OF HEAVY RAIN WAS FORECAST CONCERN TONIGHT
WITH ANOTHER ROUND OF CONVECTION ANTICIPATED TO DEVELOP OVERNIGHT.
LEANED TOWARD A BLEND OF THE ECMWF/NAM12 AND THE LATEST HRRR/HOPWRF/4.0KM
SPCWRF FOR TIMING OF THE PRECIP. BIGGEST CHANGE WAS SLOWED DOWN
THE ONSET ROUGHLY 2 TO 4 HOURS FROM PREVIOUS FORECAST PACKAGE AND
STILL MAY BE TOO QUICK FOR REDEVELOP TONIGHT.
LLJ INCREASES OVER SOUTH-CENTRAL NEBRASKA/NORTHERN KANSAS WITH THE
NOSE NUDGING INTO SOUTHWEST TO WESTERN PORTIONS OF THE IOWA PAST 06Z
THURSDAY. THE BEST THETA-E ADVECTION SURGES ACROSS SOUTHWEST IOWA
NORTHEASTWARD INTO NORTH-CENTRAL IOWA BY THURSDAY MORNING AND THE
BEST MOISTURE CONVERGENCE LOOKS TO BE B/T HIGHWAY 20 TO NEAR I-80
CORRIDORS BUT CERTAINLY NOT LIMITED TO THOSE LOCATIONS. PRECIPITABLE
WATER VALUES IN THE 2 TO 2.25 INCH RANGE OVER WESTERN IOWA AND WARM
LAYER CLOUD DEPTHS AROUND 13KFT...SO ANTICIPATING SOME EFFICIENT
RAIN PRODUCERS OVERNIGHT. MOISTURE TRANSPORT ERUPTS WITH THE LLJ
INCREASING OVERNIGHT AND WITH WEAK CORFIDI VECTORS...SUGGESTING
TRAINING POTENTIAL AS WELL. LEANED TOWARD ISSUING A FLASH FLOOD
WATCH BASED ON THE LATEST HIRES MODEL TRENDS AND 27.12Z NAM/ECMWF
CONVECTIVE/QPF TRENDS. IT WILL NOT TAKE MUCH TO GET SOME FLASH FLOOD
ISSUES OVER THE WESTERN PORTIONS OF THE FORECAST BY EARLY THURSDAY
MORNING. MAY NEED TO EXTEND/EXPAND THE WATCH FURTHER NORTH...BUT FFG
IS A BIT HIGHER ALONG THE MINNESOTA AND HAD LESSER CONFIDENCE WITH
FLASH FLOOD POTENTIAL IN THIS AREA.
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 345 PM CDT WED AUG 27 2014
MAIN CONCERNS WILL BE RAINFALL AND THREAT FOR ANY FLOODING THROUGH
THE EXTENDED PERIOD. ONGOING CONVECTION SHOULD BE DIMINISHING
THROUGH THE DAY...BUT MODERATE RAINFALL IS STILL EXPECTED AS THE
BOUNDARY LIFTS TO THE NORTHEAST AND MCS FOLLOWS AND LIFTS INTO
SOUTHERN MN. MODELS ARE NOW SPLIT ON LOCATION OF HEAVIER RAINFALL
THROUGH TOMORROW...BUT CONSENSUS IS FOR A SLIGHTLY SLOWER EVOLUTION
AND FARTHER SOUTH AND WEST MAX OVERALL...WHICH PUTS THE RAINFALL FOR
THURSDAY OVER NORTHERN IOWA A BIT LONGER INTO THE MORNING AND EARLY
AFTERNOON HOURS PRIOR TO CHANCES DIMINISHING DURING THE AFTERNOON.
EURO/GFS HAVE COME INTO LINE FARTHER SOUTH WITH TODAYS 12Z PACKAGE.
ISENTROPIC LIFT AND MOISTURE TRANSPORT FOCUSING BEST LIFT OVER
WEST CENTRAL/NORTHWEST IOWA TO START THE PERIOD AT 12Z THURSDAY
AND GRADUALLY SHIFTING THE BEST LIFT TOWARD THE IA/MN BORDER BY
18Z. SOMEWHAT COMPLICATED SCENARIO BOTH TONIGHT AND THURSDAY AS
UPPER LEVEL RIDGE AXIS HOLDING STRONG...AND EFFECTIVELY WILL
CREATE A STRONGER BOUNDARY ALOFT AS STRONG PUSH OF THETAE ADVECTION
ADVANCES NORTH...THEN HITTING A SLOWLY RETREATING RIDGE AXIS. THIS
IS PART OF THE REASON FOR THE MORE SOUTHERN FOCUS AS MASS CONVERGENCE
INCREASES OVERNIGHT/THURSDAY MORNING ACROSS THE NORTH. ONCE THE
MAIN FORCING LIFTS NORTHEAST WITH THE FIRST STRONG PUSH OF WARM
AIR...TWO MORE WEAK WAVES WILL LIFT NORTHEAST INTO THE AFTERNOON
AND OVERNIGHT HOURS WITH ADDITIONAL LIGHT TO MODERATE RAINFALL
EXPECTED THROUGH FRIDAY NIGHT. THE HIGHEST RAINFALL TOTALS WILL
OCCUR THROUGH THURSDAY...BUT ANY ADDITIONAL RAINFALL WILL ADD TO
THE POTENTIAL FOR A RISK OF SOME FLOODING...EITHER RIVER OR
ISOLATED FLASH FLOODING. WILL BE MONITORING CLOSELY OVER THE NEXT
COUPLE OF DAYS AFTER TONIGHTS EVENT UNFOLDS. WITH CLOUDS AND
RAINFALL EXPECTED...HIGHS WILL BE HELD BACK TO NEAR 70 NORTH TO
THE LOWER 80S ACROSS THE SOUTH. RAIN CHANCES REMAIN HIGH THROUGH
FRIDAY NIGHT WITH A MUCH NEEDED BREAK ARRIVING FOR MOST OF
SATURDAY AND A PART OF SUNDAY. MODELS DIFFER ON DETAILS AGAIN BY
SUNDAY...WITH EURO BEING SLIGHTLY SLOWER IN ARRIVAL OF RATHER
ROBUST LATE SUMMER SYSTEM. ANOTHER PERIOD OF MODERATE TO POSSIBLY
HEAVY RAIN COULD OCCUR SUNDAY EVENING WITH THE PASSAGE OF THE NEXT
SYSTEM. ADDITIONALLY...ALONG WITH A SHORT WAVE ARRIVING IN THE
EARLY EVENING...UPPER LEVEL WIND FIELDS AND INSTABILITY INCREASE
ENOUGH TO BE CONCERNED WITH MORE ORGANIZED SEVERE WEATHER LATE
SUNDAY AFTERNOON AND EVENING. THE MORE PROGRESSIVE NATURE OF THE
SYSTEM SHOULD RESULT IN A QUICKER EXIT...WITH A RETURN TO DRIER
WEATHER FOR TUESDAY AND WEDNESDAY. FOR NOW WILL TREND POPS DOWN ON
TUESDAY...WITH A CHANCE WE COULD BE TOTALLY DRY BY THAT TIME.
HIGHS THROUGH MOST OF THE PERIOD WILL BE IN THE 70S TO LOWER 80S.
&&
.AVIATION...28/00Z
ISSUED AT 640 PM CDT WED AUG 27 2014
PRIMARY CONCERN WILL BE CATEGORY CHANGES DRIVEN BY EXPANDING
CONVECTION OVERNIGHT. ALTHOUGH MVFR CIGS ARE IN PLACE SOUTH AND
WEST OF TAF SITES...MOST AREAS OF THE STATE REMAIN VFR AT 00Z.
EXPECT CIGS AND VSBYS TO GRADUALLY LOWER TO MVFR AND POSSIBLY IFR
BY EARLY THU MORNING AS PRECIP CROSSES THE MO RIVER INTO IA...AND
COULD LAST FOR A PROLONGED PERIOD. CONDITIONS MAY RETURN TO VFR
BY THU AFTERNOON...BUT POTENTIAL FOR AT LEAST LIGHT PRECIP WILL
LINGER THROUGH THE ENTIRE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 345 PM CDT WED AUG 27 2014
RAINFALL RATES OF 1 TO 2 INCHES PER HOUR WITH LOCALLY HIGHER
RATES ARE POSSIBLE OVER WEST-CENTRAL TO SOUTHWEST IOWA LATE
TONIGHT INTO THURSDAY. 1-HR FFG IS AROUND AN INCH AND 3-HR FFG IS
LESS THAN 2 INCHES IN MOST PLACES...SO GROUND IS PRIMED FOR FLASH
FLOODING OVERNIGHT. WITH THE WIDESPREAD QPF AMOUNTS OF 1 TO 2
INCHES FROM 09Z THURSDAY TO 00Z FRIDAY...THE RACCOON AND SMALLER
RIVER BASINS MAY SEE RISES BY THURSDAY INTO FRIDAY AND ATTM MAINLY
REACHING ACTION STAGE OR MINOR FLOOD STAGE.
HYDROLOGY CONCERNS REMAIN ACROSS THE AREA THROUGH MONDAY. WITH
ADDITIONAL RAIN EXPECTED THURSDAY NIGHT THROUGH EARLY SATURDAY
MORNING...AND ANOTHER ROUND OF POSSIBLE MODERATE TO HEAVY RAINFALL
OVER PORTIONS OF THE AREA SUNDAY AFTERNOON/EVENING...ADDITIONAL
SMALLER STREAM AND RIVER RESPONSES ARE LIKELY. ITS TOO EARLY TO
GAUGE THE OVERALL MAGNITUDE OF THE IMPACTS...WITH RIVER LEVELS
CURRENTLY RUNNING WELL BELOW FLOOD STAGE AT MOST LOCATIONS. AFTER
TOMORROW...THERE WILL BE BETTER CLARIFICATION ON THE IMPACTS
EXPECTED OVER THE WEEKEND.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 3 AM CDT THURSDAY THROUGH THURSDAY
MORNING FOR ADAIR-ADAMS-AUDUBON-CALHOUN-CARROLL-CASS-CLARKE-
CRAWFORD-DALLAS-DECATUR-GREENE-GUTHRIE-MADISON-RINGGOLD-SAC-
TAYLOR-UNION.
&&
$$
UPDATE...SMALL
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...SMALL
HYDROLOGY...PODRAZIK/REV
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1228 PM CDT Tue Aug 26 2014
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 401 AM CDT TUE AUG 26 2014
Early this morning a broad mid-level ridge remained anchored over
the southeastern quadrant of the U.S. with a deepening mid-level
trough over the Great Basin area. With this pattern in place,
southwesterly flow aloft prevailed across the central U.S. with
water vapor imagery showing a few weak embedded shortwaves
developing across Kansas and Nebraska early this morning. At the
surface, low pressure was in place with a fairly stationary boundary
across south central Kansas and extending into northeast Kansas,
essentially bisecting the forecast area. With the support of a
stronger embedded shortwave, an MCS quickly developed across eastern
Nebraska early this morning and persisted through the overnight
hours as it was supported by the low-level jet and decent isentropic
lift. A weaker shortwave was noted across central Kansas, which
sparked a cluster of showers and thunderstorms overnight. However,
this activity was gradually weakening as outflow boundaries
continued to gust out ahead of the storms. As a result, local radar
showed several outflow boundaries situated across the region from
this activity. Mid-level clouds were in place over eastern Kansas,
providing better insolation and keeping temperatures more mild in
the mid/upper 70s. However, cooler conditions were noted over north
central Kansas as a result of the rain-cooled air, bringing
temperatures down into the mid 60s to low 70s.
The precipitation forecast continues to be a challenge in the short
term as we continue to deal with a stationary boundary over the
forecast area, passing weak embedded shortwaves, and lingering
outflow boundaries from overnight convection. The HRRR has been
handling the morning activity fairly well and shows the
precipitation lifting northward and becoming more focused near the
Kansas/Nebraska border before finally diminishing by mid to late
morning. However, there is uncertainty with whether or not any
additional convection will develop near the stationary boundary
and/or along any of the lingering outflow boundaries this afternoon. While a
few models are hinting at this redevelopment, they vary with regards
to the location of the precipitation. At this time, have increasing
PoPs during the afternoon hours into this evening across the
northern half of the forecast area. A stronger embedded shortwave
may once again track across north central Kansas into Nebraska late
tonight, supporting overnight convection primarily near the
Kansas/Nebraska border. While the potential for severe weather is
low, cannot rule out some strong wind gusts and locally heavy rain.
With this set-up in place, temperatures are also a challenge for
today as they will be greatly affected by any precipitation that
develops. In general, expect slightly cooler conditions across far
northern Kansas where precipitation may linger this morning and
potentially redevelop this afternoon. However, conditions may still
heat up across east central Kansas as this region may stay mostly
dry through the day. Afternoon highs in this area could reach into
the mid/upper 90s with heat indices reaching into the 100 to 103
degree range. This area may be close to heat advisory criteria, but
due to the uncertainty in the development of any afternoon
convection, have not issued one at this time but will need to
closely monitor through the day. Low temperatures tonight are
expected to drop into the upper 60s north to low 70s south.
.LONG TERM...(Wednesday through Monday)
Issued at 401 AM CDT TUE AUG 26 2014
Wednesday will likely see an ongoing MCS across Nebraska as models
focus on areas north of the Kansas border. Expect outflow boundaries
to be present across the northern CWA and possibly some ongoing
convection through the morning hours. Left over boundaries may also
be a focus for additional development in the afternoon as well.
Wednesday night into Thursday energy will eject out of the Rockies
trough across western Kansas and Nebraska this along with the low
level jet should fuel yet another MCS across the Plains mainly
across Nebraska. Western Kansas convection will move east into the
CWA Wednesday night and into Thursday morning. Additionally Nebraska
MCS could also clip the northern counties and have maintained
highest probabilities of showers and thunderstorms to the north of
I-70.
The models slowly move the upper trough across the Rockies and
Plains as it is cut off from the westerlies. The 00Z GFS and the 00Z
ECMWF continue to be in agreement with the speed of the trough
through the end of the week while the GFS ensemble mean is just a
tad faster as is the GEM with the passage of the trough axis across
eastern Kansas and western Missouri. Front should move into central
Kansas Thursday night into Friday then progress slowly across
eastern Kansas through Saturday. The front will be a focus for
convection as well as locally heavy rainfall as precipitable water
values of 1.50 to 2.00 inches will be in place. Good moisture
transport will continue each night across the plains as the low
level jet increases and larger scale ascent increases with the
approach of the upper trough. Some convection may linger into Sunday
in the east with another chance of thunderstorms late Sunday night
and into Monday as a wave moves through the Zonal flow across the
Central Plains. Temperatures will gradually cool by the end of the
week with Wednesday being the warmest day especially south of I-70.
Near normal temperatures in the upper 80s to lower 90s are expected
from Thursday through Monday.
&&
.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1227 PM CDT TUE AUG 26 2014
VFR conditions are expected throughout the period, with easterly winds
becoming more southerly overnight. There is a possibility of thunderstorms
this evening/tonight, but right now location and even actual
occurrence is uncertain so they have been left out of this TAF
package.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Hennecke
LONG TERM...53
AVIATION...Barjenbruch/Heller
AREA FORECAST DISCUSSION
NWS TOPEKA KS
645 AM CDT Tue Aug 26 2014
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 401 AM CDT TUE AUG 26 2014
Early this morning a broad mid-level ridge remained anchored over
the southeastern quadrant of the U.S. with a deepening mid-level
trough over the Great Basin area. With this pattern in place,
southwesterly flow aloft prevailed across the central U.S. with
water vapor imagery showing a few weak embedded shortwaves
developing across Kansas and Nebraska early this morning. At the
surface, low pressure was in place with a fairly stationary boundary
across south central Kansas and extending into northeast Kansas,
essentially bisecting the forecast area. With the support of a
stronger embedded shortwave, an MCS quickly developed across eastern
Nebraska early this morning and persisted through the overnight
hours as it was supported by the low-level jet and decent isentropic
lift. A weaker shortwave was noted across central Kansas, which
sparked a cluster of showers and thunderstorms overnight. However,
this activity was gradually weakening as outflow boundaries
continued to gust out ahead of the storms. As a result, local radar
showed several outflow boundaries situated across the region from
this activity. Mid-level clouds were in place over eastern Kansas,
providing better insolation and keeping temperatures more mild in
the mid/upper 70s. However, cooler conditions were noted over north
central Kansas as a result of the rain-cooled air, bringing
temperatures down into the mid 60s to low 70s.
The precipitation forecast continues to be a challenge in the short
term as we continue to deal with a stationary boundary over the
forecast area, passing weak embedded shortwaves, and lingering
outflow boundaries from overnight convection. The HRRR has been
handling the morning activity fairly well and shows the
precipitation lifting northward and becoming more focused near the
Kansas/Nebraska border before finally diminishing by mid to late
morning. However, there is uncertainty with whether or not any
additional convection will develop near the stationary boundary
and/or along any of the lingering outflow boundaries this afternoon. While a
few models are hinting at this redevelopment, they vary with regards
to the location of the precipitation. At this time, have increasing
PoPs during the afternoon hours into this evening across the
northern half of the forecast area. A stronger embedded shortwave
may once again track across north central Kansas into Nebraska late
tonight, supporting overnight convection primarily near the
Kansas/Nebraska border. While the potential for severe weather is
low, cannot rule out some strong wind gusts and locally heavy rain.
With this set-up in place, temperatures are also a challenge for
today as they will be greatly affected by any precipitation that
develops. In general, expect slightly cooler conditions across far
northern Kansas where precipitation may linger this morning and
potentially redevelop this afternoon. However, conditions may still
heat up across east central Kansas as this region may stay mostly
dry through the day. Afternoon highs in this area could reach into
the mid/upper 90s with heat indices reaching into the 100 to 103
degree range. This area may be close to heat advisory criteria, but
due to the uncertainty in the development of any afternoon
convection, have not issued one at this time but will need to
closely monitor through the day. Low temperatures tonight are
expected to drop into the upper 60s north to low 70s south.
.LONG TERM...(Wednesday through Monday)
Issued at 401 AM CDT TUE AUG 26 2014
Wednesday will likely see an ongoing MCS across Nebraska as models
focus on areas north of the Kansas border. Expect outflow boundaries
to be present across the northern CWA and possibly some ongoing
convection through the morning hours. Left over boundaries may also
be a focus for additional development in the afternoon as well.
Wednesday night into Thursday energy will eject out of the Rockies
trough across western Kansas and Nebraska this along with the low
level jet should fuel yet another MCS across the Plains mainly
across Nebraska. Western Kansas convection will move east into the
CWA Wednesday night and into Thursday morning. Additionally Nebraska
MCS could also clip the northern counties and have maintained
highest probabilities of showers and thunderstorms to the north of
I-70.
The models slowly move the upper trough across the Rockies and
Plains as it is cut off from the westerlies. The 00Z GFS and the 00Z
ECMWF continue to be in agreement with the speed of the trough
through the end of the week while the GFS ensemble mean is just a
tad faster as is the GEM with the passage of the trough axis across
eastern Kansas and western Missouri. Front should move into central
Kansas Thursday night into Friday then progress slowly across
eastern Kansas through Saturday. The front will be a focus for
convection as well as locally heavy rainfall as precipitable water
values of 1.50 to 2.00 inches will be in place. Good moisture
transport will continue each night across the plains as the low
level jet increases and larger scale ascent increases with the
approach of the upper trough. Some convection may linger into Sunday
in the east with another chance of thunderstorms late Sunday night
and into Monday as a wave moves through the Zonal flow across the
Central Plains. Temperatures will gradually cool by the end of the
week with Wednesday being the warmest day especially south of I-70.
Near normal temperatures in the upper 80s to lower 90s are expected
from Thursday through Monday.
&&
.AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning)
Issued at 644 AM CDT TUE AUG 26 2014
For the 12z TAFs, winds have shifted to the north with the stalled
front positioned near the TAF sites. These winds should veer toward
the southeast through the day as the boundary shifts a bit further
north. Scattered showers and thunderstorms have developed north and
west of KMHK and expect this scattered pop-up activity to continue
to develop near KMHK through mid to late morning. There is the
potential for showers and thunderstorms to redevelop this afternoon
along lingering boundaries from the early morning convection,
however there is too much uncertainty with regards to location let
alone occurrence to warrant a mention in the TAFs at this time, but
this potential will need to be monitored closely in future updates.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Hennecke
LONG TERM...53
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS TOPEKA KS
401 AM CDT Tue Aug 26 2014
.SHORT TERM...(Today and Tonight)
Issued at 401 AM CDT TUE AUG 26 2014
Early this morning a broad mid-level ridge remained anchored over
the southeastern quadrant of the U.S. with a deepening mid-level
trough over the Great Basin area. With this pattern in place,
southwesterly flow aloft prevailed across the central U.S. with
water vapor imagery showing a few weak embedded shortwaves
developing across Kansas and Nebraska early this morning. At the
surface, low pressure was in place with a fairly stationary boundary
across south central Kansas and extending into northeast Kansas,
essentially bisecting the forecast area. With the support of a
stronger embedded shortwave, an MCS quickly developed across eastern
Nebraska early this morning and persisted through the overnight
hours as it was supported by the low-level jet and decent isentropic
lift. A weaker shortwave was noted across central Kansas, which
sparked a cluster of showers and thunderstorms overnight. However,
this activity was gradually weakening as outflow boundaries
continued to gust out ahead of the storms. As a result, local radar
showed several outflow boundaries situated across the region from
this activity. Mid-level clouds were in place over eastern Kansas,
providing better insolation and keeping temperatures more mild in
the mid/upper 70s. However, cooler conditions were noted over north
central Kansas as a result of the rain-cooled air, bringing
temperatures down into the mid 60s to low 70s.
The precipitation forecast continues to be a challenge in the short
term as we continue to deal with a stationary boundary over the
forecast area, passing weak embedded shortwaves, and lingering
outflow boundaries from overnight convection. The HRRR has been
handling the morning activity fairly well and shows the
precipitation lifting northward and becoming more focused near the
Kansas/Nebraska border before finally diminishing by mid to late
morning. However, there is uncertainty with whether or not any
additional convection will develop near the stationary boundary
and/or along any of the lingering outflow boundaries this afternoon. While a
few models are hinting at this redevelopment, they vary with regards
to the location of the precipitation. At this time, have increasing
PoPs during the afternoon hours into this evening across the
northern half of the forecast area. A stronger embedded shortwave
may once again track across north central Kansas into Nebraska late
tonight, supporting overnight convection primarily near the
Kansas/Nebraska border. While the potential for severe weather is
low, cannot rule out some strong wind gusts and locally heavy rain.
With this set-up in place, temperatures are also a challenge for
today as they will be greatly affected by any precipitation that
develops. In general, expect slightly cooler conditions across far
northern Kansas where precipitation may linger this morning and
potentially redevelop this afternoon. However, conditions may still
heat up across east central Kansas as this region may stay mostly
dry through the day. Afternoon highs in this area could reach into
the mid/upper 90s with heat indices reaching into the 100 to 103
degree range. This area may be close to heat advisory criteria, but
due to the uncertainty in the development of any afternoon
convection, have not issued one at this time but will need to
closely monitor through the day. Low temperatures tonight are
expected to drop into the upper 60s north to low 70s south.
.LONG TERM...(Wednesday through Monday)
Issued at 401 AM CDT TUE AUG 26 2014
Wednesday will likely see an ongoing MCS across Nebraska as models
focus on areas north of the Kansas border. Expect outflow boundaries
to be present across the northern CWA and possibly some ongoing
convection through the morning hours. Left over boundaries may also
be a focus for additional development in the afternoon as well.
Wednesday night into Thursday energy will eject out of the Rockies
trough across western Kansas and Nebraska this along with the low
level jet should fuel yet another MCS across the Plains mainly
across Nebraska. Western Kansas convection will move east into the
CWA Wednesday night and into Thursday morning. Additionally Nebraska
MCS could also clip the northern counties and have maintained
highest probabilities of showers and thunderstorms to the north of
I-70.
The models slowly move the upper trough across the Rockies and
Plains as it is cut off from the westerlies. The 00Z GFS and the 00Z
ECMWF continue to be in agreement with the speed of the trough
through the end of the week while the GFS ensemble mean is just a
tad faster as is the GEM with the passage of the trough axis across
eastern Kansas and western Missouri. Front should move into central
Kansas Thursday night into Friday then progress slowly across
eastern Kansas through Saturday. The front will be a focus for
convection as well as locally heavy rainfall as precipitable water
values of 1.50 to 2.00 inches will be in place. Good moisture
transport will continue each night across the plains as the low
level jet increases and larger scale ascent increases with the
approach of the upper trough. Some convection may linger into Sunday
in the east with another chance of thunderstorms late Sunday night
and into Monday as a wave moves through the Zonal flow across the
Central Plains. Temperatures will gradually cool by the end of the
week with Wednesday being the warmest day especially south of I-70.
Near normal temperatures in the upper 80s to lower 90s are expected
from Thursday through Monday.
&&
.AVIATION...(For the 06Z TAFs through 06Z Tuesday Night)
Issued at 1143 PM CDT MON AUG 25 2014
Will maintain a dry/VFR forecast for THE KTOP/KFOE terminals through
the period as confidence on either of these terminal being
directly affected by convection is low. However...feel that
decaying MCS may get closer to KMHK behind outflow boundary so
will maintain VCTS at KMHK until MCS is expected to dissipate by
09z. As convection continues to rapidly develop to the north in NE...
confidence is increasing of another outflow boundary bringing winds
back around to the northeast late this morning before veering to
the southeast aft 18z in return flow. With little or no precip
expected in the terminals...will maintain only vfr mid and high
clouds and no vsby restrictions.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Hennecke
LONG TERM...53
AVIATION...63
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
347 AM CDT TUE AUG 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 148 AM CDT TUE AUG 26 2014
NAM AND GFS WERE BOTH IN GOOD AGREEMENT WITH AN UPPER LEVEL
TROUGH MOVING ACROSS NEW MEXICO TODAY AND THEN ACROSS WESTERN
KANSAS DURING THE OVERNIGHT HOURS. AS THIS UPPER LEVEL DISTURBANCE
APPROACHESTODAY AN AREA OF LOW PRESSURE WILL DEVELOP ACROSS
SOUTHEAST COLORADO AND A SURFACE BOUNDARY LOCATED NEAR THE
OKLAHOMA BORDER EARLIER THIS MORNING WILL BEGIN TO LIFT NORTH
ACROSS SOUTHWEST KANSAS. BY LATE DAY THIS SURFACE BOUNDARY IS
EXPECTED TO EXTEND FROM SOUTHEAST COLORADO INTO NORTH CENTRAL
KANSAS WITH AN AREA OF HIGHER LOW LEVEL DEWPOINTS POOLING JUST
NORTH/WEST OF THIS SURFACE BOUNDARY. ALTHOUGH MODELS DO DISAGREE
ON JUST HOW FAR NORTH THIS BOUNDARY WILL BE BY LATE DAY THE NAM
AND GFS DO AGREE THAT LATE DAY SURFACE BASED CAPES ALONG AND NORTH
OF THIS BOUNDARY WILL RANGE FROM 1500 TO 3000 J/KG. GIVEN THE
LOCATION OF THE SURFACE BOUNDARY, LOW LEVEL MOISTURE, AND
AFTERNOON INSTABILITY WILL CONTINUE TO FAVOR THE HIGHER CHANCES
FOR CONVECTION TO BE LOCATED NORTHWEST OF AN ELKHART TO RUSH
CENTER AREAS LATE TODAY AND EARLY TONIGHT. 0-6KM SHEAR HOWEVER
FORECAST TO BE LESS THAN 20KNOTS SO A FEW STRONG PULSE
THUNDERSTORMS MAY BE POSSIBLE LATE DAY, SEVERE THUNDERSTORMS ARE
NOT ANTICIPATED AT THIS TIME BUT SMALL HAIL AND WIND GUSTS UP TO
50 MPH WILL BE POSSIBLE ACROSS FAR WESTERN KANSAS AND NORTH
CENTRAL KANSAS. TEMPERATURES TODAY WILL ONCE AGAIN CLIMB BACK INTO
THE MID TO UPPER 90S BASED ON 00Z 850MB TO 700MB TEMPERATURES FROM
THE NAM AND GFS.
AS AN UPPER LEVEL DISTURBANCE CROSSES WESTERN KANSAS EARLY
TONIGHT THE THUNDERSTORMS ACROSS WESTERN AND NORTH CENTRAL KANSAS
WILL INCREASE IN COVERAGE AND CONTINUE. AT THIS TIME WILL PLACE
THE HIGHER CHANCES JUST AHEAD OF THIS UPPER WAVE AS IT CROSSES
WESTERN KANSAS BETWEEN 03Z WEDNESDAY AND 09Z WEDNESDAY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CDT TUE AUG 26 2014
AN UPPER LEVEL LOW CURRENTLY ACROSS THE DESERT SOUTHWEST WILL TREK
EASTWARD ACROSS THE CENTRAL ROCKIES WEDNESDAY AND THURSDAY THEN
THROUGH THE CENTRAL PLAINS FRIDAY INTO SATURDAY. THIS FEATURE WILL
INCREASE LIFT ACROSS THE AREA AS IT APPROACHES AND PASSES
OVERHEAD. MID LEVELS OF THE ATMOSPHERE WILL GENERALLY BE SATURATED
THROUGH SATURDAY ALLOWING MOSTLY CLOUDY SKIES TO BE OBSERVED
ACROSS WESTERN KANSAS. TOWARDS THE SURFACE, AN AREA OF LOW
PRESSURE WILL BE POSITIONED SOMEWHERE ACROSS NORTHWEST KANSAS,
NORTHEAST COLORADO, AND SOUTHWEST NEBRASKA THROUGH WEDNESDAY NIGHT
WITH A FRONTAL BOUNDARY EXTENDING EASTWARD ACROSS THE KS/NE LINE.
A COLD FRONT IS THEN PROGGED TO MOVE THROUGH THE AREA THURSDAY
INTO THURSDAY NIGHT BEFORE STALLING OUT ACROSS CENTRAL KANSAS,
WESTERN OKLAHOMA, AND WESTERN TEXAS ON FRIDAY INTO SATURDAY. WITH
THESE FEATURES IN PLACE, THUNDERSTORM CHANCES WILL GENERALLY BE IN
THE FORECAST THROUGH FRIDAY WITH THE STORM EXITING THE AREA FRIDAY
NIGHT INTO EARLY SATURDAY MORNING. THE BEST CHANCES OF
PRECIPITATION LOOK TO BE WEDNESDAY NIGHT WHEN THE LIFT IS
STRONGEST THEN AGAIN ON FRIDAY AS MOISTURE WRAPS AROUND THE
AFOREMENTIONED LOW. THE REMAINDER OF THE EXTENDED FORECAST LOOKS
DRY AS HIGH PRESSURE BUILDS INTO THE AREA BRINGING PARTLY CLOUDY
SKIES. AS FOR TEMPERATURES, HIGHS WEDNESDAY LOOK TO TOP OUT IN THE
LOWER TO MID 90S WITH 80S EXPECTED THURSDAY THROUGH SATURDAY.
HIGHS THEN REACH INTO THE LOWER 90S SUNDAY INTO MONDAY. LOWS LOOK
TO RANGE FROM THE LOWER 60S ACROSS WEST CENTRAL KANSAS TO LOWER
70S ACROSS SOUTH CENTRAL KANSAS WEDNESDAY MORNING WITH LOWS IN THE
60S THURSDAY MORNING THROUGH MONDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1222 AM CDT TUE AUG 26 2014
LATEST RADAR TREND SHOWING CONVECTION TAPERING OFF ACROSS
SOUTHWEST KANSAS AS OF 05Z. THIS WAS CONSISTENT WITH THE LATEST
NAM AND HRRR SOLUTION. THESE MODELS ALSO INDICATED THE OVERNIGHT
CONVECTION EXPECTED ACROSS NORTHWEST AND NORTH CENTRAL KANSAS WILL
STAY NORTH/NORTHWEST OF THE HAYS AREA. BUFR SOUNDINGS INDICATING
CLOUD COVER WILL BE AT OR ABOVE THE 10000 FT AGL OVERNIGHT AND
EARLY TUESDAY SO VFR CONDITIONS ARE EXPECTED. EASTERLY WINDS AT
10KNOTS OR LESS OVERNIGHT WILL GRADUALLY VEER TO THE SOUTHEAST AND
INCREASE BY LATE MORNING TO AROUND 15 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 95 69 92 69 / 20 30 60 40
GCK 93 67 90 67 / 30 50 40 50
EHA 93 66 89 65 / 40 50 40 40
LBL 94 68 92 68 / 20 20 40 40
HYS 93 68 91 69 / 30 50 60 70
P28 99 73 96 72 / 10 10 30 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...HOVORKA_42
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
153 AM CDT TUE AUG 26 2014
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 148 AM CDT TUE AUG 26 2014
NAM AND GFS WERE BOTH IN GOOD AGREEMENT WITH AN UPPER LEVEL
TROUGH MOVING ACROSS NEW MEXICO TODAY AND THEN ACROSS WESTERN
KANSAS DURING THE OVERNIGHT HOURS. AS THIS UPPER LEVEL DISTURBANCEAPPROACHES
TODAY AN AREA OF LOW PRESSURE WILL DEVELOP ACROSS SOUTHEAST
COLORADO AND A SURFACE BOUNDARY LOCATED NEAR THE OKLAHOMA BORDER
EARLIER THIS MORNING WILL BEGIN TO LIFT NORTH ACROSS SOUTHWEST
KANSAS. BY LATE DAY THIS SURFACE BOUNDARY IS EXPECTED TO EXTEND
FROM SOUTHEAST COLORADO INTO NORTH CENTRAL KANSAS WITH AN AREA OF
HIGHER LOW LEVEL DEWPOINTS POOLING JUST NORTH/WEST OF THIS SURFACE
BOUNDARY. ALTHOUGH MODELS DO DISAGREE ON JUST HOW FAR NORTH THIS
BOUNDARY WILL BE BY LATE DAY THE NAM AND GFS DO AGREE THAT LATE
DAY SURFACE BASED CAPES ALONG AND NORTH OF THIS BOUNDARY WILL
RANGE FROM 1500 TO 3000 J/KG. GIVEN THE LOCATION OF THE SURFACE
BOUNDARY, LOW LEVEL MOISTURE, AND AFTERNOON INSTABILITY WILL
CONTINUE TO FAVOR THE HIGHER CHANCES FOR CONVECTION TO BE LOCATED
NORTHWEST OF AN ELKHART TO RUSH CENTER AREAS LATE TODAY AND EARLY
TONIGHT. 0-6KM SHEAR HOWEVER FORECAST TO BE LESS THAN 20KNOTS SO A
FEW STRONG PULSE THUNDERSTORMS MAY BE POSSIBLE LATE DAY, SEVERE
THUNDERSTORMS ARE NOT ANTICIPATED AT THIS TIME BUT SMALL HAIL AND
WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE ACROSS FAR WESTERN KANSAS
AND NORTH CENTRAL KANSAS. TEMPERATURES TODAY WILL ONCE AGAIN CLIMB
BACK INTO THE MID TO UPPER 90S BASED ON 00Z 850MB TO 700MB
TEMPERATURES FROM THE NAM AND GFS.
AS AN UPPER LEVEL DISTURBANCE CROSSES WESTERN KANSAS EARLY
TONIGHT THE THUNDERSTORMS ACROSS WESTERN AND NORTH CENTRAL KANSAS
WILL INCREASE IN COVERAGE AND CONTINUE. AT THIS TIME WILL PLACE
THE HIGHER CHANCES JUST AHEAD OF THIS UPPER WAVE AS IT CROSSES
WESTERN KANSAS BETWEEN 03Z WEDNESDAY AND 09Z WEDNESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 304 PM CDT MON AUG 25 2014
AN UPPER LEVEL LOW OVER THE WESTERN UNITED STATES WILL SLOWLY
PROGRESS EASTWARD AND PASS ACROSS WESTERN KANSAS BY FRIDAY. AHEAD
OF THIS FEATURE, LOW LEVEL MOISTURE WILL BE PLENTIFUL AND 700MB
TEMPERATURES WILL COOL TO AROUND 10C. THE BEST CHANCE OF THE MORE
WIDESPREAD AND HEAVY RAINFALL THROUGH WEDNESDAY WILL BE ALONG AND
NORTH OF A STALLED OUT FRONTAL BOUNDARY ACROSS NORTHERN KANSAS AND
POINTS NORTHWARD FROM THERE WHERE LOW TO MID LEVEL MOISTURE WILL BE
PLENTIFUL. MID LEVEL TEMPERATURES ARE PROGGED TO COOL TO AROUND
10C THROUGH WEDNESDAY ACROSS SOUTHWEST KANSAS SO THAT ISOLATED TO
SCATTERED THUNDERSTORMS ARE POSSIBLE EVEN SOUTH OF THE FRONT. BY
THURSDAY AND FRIDAY AS THE UPPER LEVEL SYSTEM GETS CLOSER AND MID
LEVEL TEMPERATURES DROP FURTHER, THE CHANCE FOR WIDESPREAD
THUNDERSTORM ACTIVITY WILL INCREASE ACROSS SOUTHWESTERN KANSAS,
ALONG WITH COOLER TEMPERATURES. HIGH TEMPERATURES WILL STILL BE IN
THE LOWER 90S ON WEDNESDAY, AND THEN FALL INTO THE 80S BY THURSDAY
AND FRIDAY AS CLOUD COVER AND PRECIPITATION INCREASE. THE ECMWF IS
SLOWER TO BRING THIS SYSTEM THROUGH WESTERN KANSAS WITH THE GFS
THE MOST PROGRESSIVE. BUT IT DOES APPEAR THAT THE SIGNIFICANT
RAINFALL WILL BE OVER BY FRIDAY NIGHT. A SLOW WARMING TREND CAN BE
EXPECTED THEREAFTER AS THE MID LEVEL FLOW BECOMES MORE WESTERLY
ACROSS THE ROCKIES, WITH LEE TROUGHING BECOMING ESTABLISHED.
THUNDERSTORM ACTIVITY MAY INCREASE AGAIN SOMETIME EARLY NEXT WEEK
AS LOW LEVEL MOISTURE SURGES NORTH FROM THE GULF OF MEXICO ALONG
THE SOUTHERN EDGE OF THE WESTERLIES. BUT MID LEVEL TEMPERATURES
WILL ONCE AGAIN BECOME QUITE WARM SO THAT MID LEVEL CAPPING MAY
SUPPRESS CONVECTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1222 AM CDT TUE AUG 26 2014
LATEST RADAR TREND SHOWING CONVECTION TAPERING OFF ACROSS
SOUTHWEST KANSAS AS OF 05Z. THIS WAS CONSISTENT WITH THE LATEST
NAM AND HRRR SOLUTION. THESE MODELS ALSO INDICATED THE OVERNIGHT
CONVECTION EXPECTED ACROSS NORTHWEST AND NORTH CENTRAL KANSAS WILL
STAY NORTH/NORTHWEST OF THE HAYS AREA. BUFR SOUNDINGS INDICATING
CLOUD COVER WILL BE AT OR ABOVE THE 10000 FT AGL OVERNIGHT AND
EARLY TUESDAY SO VFR CONDITIONS ARE EXPECTED. EASTERLY WINDS AT
10KNOTS OR LESS OVERNIGHT WILL GRADUALLY VEER TO THE SOUTHEAST AND
INCREASE BY LATE MORNING TO AROUND 15 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 95 69 92 68 / 30 30 30 40
GCK 93 67 90 66 / 40 40 40 50
EHA 93 66 88 65 / 40 30 40 40
LBL 94 68 92 67 / 40 30 40 40
HYS 93 68 91 67 / 40 50 50 60
P28 99 73 96 71 / 10 10 30 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...FINCH
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1225 AM CDT TUE AUG 26 2014
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 241 PM CDT MON AUG 25 2014
A COLD FRONT HAS SAGGED SOUTHWARD AND AUGMENTED BY EARLIER
CONVECTION WAS LOCATED BETWEEN GARDEN CITY AND HAYS. THIS BOUNDARY
IS FORECAST TO BE NEARLY STATIONARY INTO THIS EVENING. THE BOUNDARY
WILL SERVE AS A FOCUS FOR LATE AFTERNOON AND OVERNIGHT
THUNDERSTORMS. MODERATE INSTABILITY WITH CAPE FORECAST OF AROUND
2500 J/KG NEAR AND NORTH OF THIS FRONTAL BOUNDARY. COULD SEE SOME
STRONG OUTFLOW WINDS OF 50 MPH OR HIGHER AND SOME SMALL HAIL. A FEW
STORMS COULD APPROACH NEAR SEVERE LIMITS INTO THE EVENING. WEAK MID
LEVEL WIND FIELDS AND SHEAR SHOULD BE ENOUGH TO KEEP MOST STORMS
BELOW SEVERE LIMITS. THE BEST POTENTIAL FOR STORMS WILL BE GENERALLY
NORTH OF HIGHWAY 96 AND INTO THE I-70 CORRIDOR. ALSO SOME POTENTIAL
FOR LOCALLY HEAVY RAINFALL IN THOSE AREAS IF THUNDERSTORMS CAN TRAIN
OVER THE SAME AREAS. WILL KEEP SMALL POPS GOING SOUTH OF THE
BOUNDARY INTO THE OVERNIGHT PERIODS. SOUTHEAST WINDS WILL BECOME
LIGHT AND VARIABLE TOWARDS MORNING WITH OUTFLOWS CAUSING THE FRONT
TO SAG MORE SOUTH INTO SOUTHWEST KANSAS. OVERNIGHT LOWS WILL BE MILD
IN THE MID TO UPPER 60S. PARTS OF SOUTH CENTRAL KANSAS NEAR SAINT
JOHN TO COLDWATER AND EAST MAY NOT SEE ANY STORMS AND BE WARMER
OVERNIGHT AROUND 70.
FOR TUESDAY, WILL CONTINUE WITH 20 TO 30 PERCENT CHANCES FOR
THUNDERSTORMS, MAINLY IN THE AFTERNOON, GENERALLY WEST OF A LARNED
TO COLDWATER LINE. THUNDERSTORMS MAY AGAIN FORM WHERE ANY BOUNDARIES
ARE LEFT OVER. WEAKER INSTABILITY AND WIND FIELDS SHOULD PRECLUDE
SEVERE THUNDERSTORM CHANCES. WINDS WILL BE LIGHT AND VARIABLE THEN
BECOMING SOUTHEASTERLY 15 TO 20 MPH UNDER PARTLY CLOUDY SKIES. HIGHS
WILL BE COOLER WITH MOIST UPSLOPE FLOW AND RESIDUAL CLOUDINESS
MAINLY EAST OF DODGE CITY. HIGHS WILL RANGE FROM THE LOW TO MID 90S
WEST OF DODGE CITY TO THE MID AND UPPER 90S EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 304 PM CDT MON AUG 25 2014
AN UPPER LEVEL LOW OVER THE WESTERN UNITED STATES WILL SLOWLY
PROGRESS EASTWARD AND PASS ACROSS WESTERN KANSAS BY FRIDAY. AHEAD
OF THIS FEATURE, LOW LEVEL MOISTURE WILL BE PLENTIFUL AND 700MB
TEMPERATURES WILL COOL TO AROUND 10C. THE BEST CHANCE OF THE MORE
WIDESPREAD AND HEAVY RAINFALL THROUGH WEDNESDAY WILL BE ALONG AND
NORTH OF A STALLED OUT FRONTAL BOUNDARY ACROSS NORTHERN KANSAS AND
POINTS NORTHWARD FROM THERE WHERE LOW TO MID LEVEL MOISTURE WILL BE
PLENTIFUL. MID LEVEL TEMPERATURES ARE PROGGED TO COOL TO AROUND
10C THROUGH WEDNESDAY ACROSS SOUTHWEST KANSAS SO THAT ISOLATED TO
SCATTERED THUNDERSTORMS ARE POSSIBLE EVEN SOUTH OF THE FRONT. BY
THURSDAY AND FRIDAY AS THE UPPER LEVEL SYSTEM GETS CLOSER AND MID
LEVEL TEMPERATURES DROP FURTHER, THE CHANCE FOR WIDESPREAD
THUNDERSTORM ACTIVITY WILL INCREASE ACROSS SOUTHWESTERN KANSAS,
ALONG WITH COOLER TEMPERATURES. HIGH TEMPERATURES WILL STILL BE IN
THE LOWER 90S ON WEDNESDAY, AND THEN FALL INTO THE 80S BY THURSDAY
AND FRIDAY AS CLOUD COVER AND PRECIPITATION INCREASE. THE ECMWF IS
SLOWER TO BRING THIS SYSTEM THROUGH WESTERN KANSAS WITH THE GFS
THE MOST PROGRESSIVE. BUT IT DOES APPEAR THAT THE SIGNIFICANT
RAINFALL WILL BE OVER BY FRIDAY NIGHT. A SLOW WARMING TREND CAN BE
EXPECTED THEREAFTER AS THE MID LEVEL FLOW BECOMES MORE WESTERLY
ACROSS THE ROCKIES, WITH LEE TROUGHING BECOMING ESTABLISHED.
THUNDERSTORM ACTIVITY MAY INCREASE AGAIN SOMETIME EARLY NEXT WEEK
AS LOW LEVEL MOISTURE SURGES NORTH FROM THE GULF OF MEXICO ALONG
THE SOUTHERN EDGE OF THE WESTERLIES. BUT MID LEVEL TEMPERATURES
WILL ONCE AGAIN BECOME QUITE WARM SO THAT MID LEVEL CAPPING MAY
SUPPRESS CONVECTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1222 AM CDT TUE AUG 26 2014
LATEST RADAR TREND SHOWING CONVECTION TAPERING OFF ACROSS
SOUTHWEST KANSAS AS OF 05Z. THIS WAS CONSISTENT WITH THE LATEST
NAM AND HRRR SOLUTION. THESE MODELS ALSO INDICATED THE OVERNIGHT
CONVECTION EXPECTED ACROSS NORTHWEST AND NORTH CENTRAL KANSAS WILL
STAY NORTH/NORTHWEST OF THE HAYS AREA. BUFR SOUNDINGS INDICATING
CLOUD COVER WILL BE AT OR ABOVE THE 10000 FT AGL OVERNIGHT AND
EARLY TUESDAY SO VFR CONDITIONS ARE EXPECTED. EASTERLY WINDS AT
10KNOTS OR LESS OVERNIGHT WILL GRADUALLY VEER TO THE SOUTHEAST AND
INCREASE BY LATE MORNING TO AROUND 15 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 69 92 68 87 / 30 30 40 40
GCK 67 90 66 86 / 40 40 50 40
EHA 66 88 65 84 / 30 40 40 40
LBL 68 92 67 87 / 30 40 40 40
HYS 68 91 67 86 / 50 50 60 40
P28 73 96 71 91 / 10 30 30 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KRUSE
LONG TERM...FINCH
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
105 PM EDT Tue Aug 26 2014
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1125 AM EDT Tue Aug 26 2014
Forecast is largely on track this morning, although did make an
update to add some isolated showers or a storm west of the I-65
corridor. Current analysis shows dew points starting to pool in this
area on the western edge of the surface high. SPC mesoanalysis
moisture convergence parameter also confirms this. Additionally,
have support from the HRRR that isolated to widely scattered
showers/storms should pop up by early afternoon.
Forecast soundings indicate at least moderately strong instability
will be available this afternoon due to the very moist low levels
combined with steep low level lapse rates. Deep layer flow is quite
weak, so only expect localized gusty winds in the vicinity of
showers/storms and some brief heavy rainfall.
.SHORT TERM (Now through Wednesday)...
Issued at 317 AM EDT Tue Aug 26 2014
Morning IR satellite and surface observations reveal mostly clear
skies across southern Indiana and central Kentucky. Some patchy fog
has developed in the typical fog prone areas and in areas that
picked up a bit of rainfall Monday afternoon. Temperatures remained
quite mild with readings in the lower-middle 70s. Expect quiet
weather to continue through the remainder of the overnight hours
with overnight minimums dropping only a few more degrees or so.
For Today/Tonight, the short term multi-model consensus continues to
be in agreement with increasing the strength of the mid-level ridge
axis overhead. This should result in another mostly sunny and muggy
day across the region. With some additional mid-level warming and
slight drying of the column, current thinking is that convection
will be a bit more isolated. However, high resolution convective
allowing models suggest that storms will fire up to our north along
the periphery of the ridge axis. These could slide southward in the
afternoon and affect our far northern areas of southern Indiana.
Thus, have maintained an isolated storm chance up that way for the
late afternoon hours. Afternoon highs will be similar to Monday
with readings in the upper 80s to the lower 90s. Skies are expected
to clear back out tonight as any convection dissipates after
sunset. Overnight lows will cool into the upper 60s in the far NE
to the lower 70s in the central and southwest.
For Wednesday, the upper level ridge axis is expected to shift a bit
further to the south along with the surface ridge axis. This will
allow a surface frontal boundary to sag southward through central
Indiana. Convection is expected to develop during the afternoon
hours along this front and this activity may eventually spread
southward into southern Indiana and the northern half of KY. For
now, isolated-scattered PoPs still look like a good bet at this
time. Afternoon highs will be warm once again with readings topping
out in the upper 80s in the north with lower 90s in the south.
.LONG TERM (Wednesday Night through Monday)...
Issued at 307 AM EDT Tue Aug 26 2014
Ridging across the southeastern United States will slowly shift
eastward through the long term. As it does so a shortwave trough
will approach from the west, moving across the upper Midwest Sunday
and across the Great Lakes region by Monday morning. At the surface
a weak frontal boundary near the KY/TN border at the beginning of
the period will eventually push back northward as a warm front
Friday.
For Wednesday night a few residual showers or storms may be ongoing
at the start of the period. However, these should dissipate
overnight with mostly dry conditions expected. Diurnal storms are
expected once again on Thursday and Friday, particularly in the
vicinity of the frontal boundaries. The better chance will be on
Thursday with scattered storms across the region. Friday`s storms
look to be more isolated in nature.
Rain chances will increase through the weekend as the upper level
trough nears and its associated surface low lifts north of the
region. The best chances for storms this weekend looks to be on
Sunday as precipitable water values rise to around 1.9 inches and we
become moderately unstable. Will keep chances in the 40-50% range
right now considering there is still some differences in the
development of the system between the model solutions. Monday will
see a return to the more summertime diurnal pattern of storms before
a cold front approaches towards midweek.
Temperatures will be in the upper 80s to lower 90s through Saturday
with lows in the upper 60s to lower 70s. With rain and clouds
expected Sunday into Monday we should see a bit of a cool down,
particularly on Sunday with highs in the lower to mid 80s expected.
This will not last however, as a return to upper 80s is expected by
Tuesday.
&&
.AVIATION (18Z TAF Update)...
Issued at 105 PM EDT Tue Aug 26 2014
A few showers have popped up around the BWG terminal early this
afternoon where the best low level moisture convergence is occurring
on the western edge of the surface high. Have included VCSH mention
at BWG through sundown. SDF would be the other site that could
experience a shower or two this afternoon/evening, however coverage
is less certain in this area so will leave dry for now. Expect
generally light and variable winds today with any noticeable
gradient out of the ENE. Expect only Sct Cu around 4 k feet.
Some fog will be possible at the TAF sites again toward dawn, with
light and variable winds and scattered clouds around 4 k feet once
again on Wednesday. Some showers may settle across SDF/BWG tomorrow
afternoon ahead of a frontal boundary.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........BJS
Short Term.....MJ
Long Term......EER
Aviation.......BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1126 AM EDT Tue Aug 26 2014
...Forecast Update...
Issued at 1125 AM EDT Tue Aug 26 2014
Forecast is largely on track this morning, although did make an
update to add some isolated showers or a storm west of the I-65
corridor. Current analysis shows dew points starting to pool in this
area on the western edge of the surface high. SPC mesoanalysis
moisture convergence parameter also confirms this. Additionally,
have support from the HRRR that isolated to widely scattered
showers/storms should pop up by early afternoon.
Forecast soundings indicate at least moderately strong instability
will be available this afternoon due to the very moist low levels
combined with steep low level lapse rates. Deep layer flow is quite
weak, so only expect localized gusty winds in the vicinity of
showers/storms and some brief heavy rainfall.
.SHORT TERM (Now through Wednesday)...
Issued at 317 AM EDT Tue Aug 26 2014
Morning IR satellite and surface observations reveal mostly clear
skies across southern Indiana and central Kentucky. Some patchy fog
has developed in the typical fog prone areas and in areas that
picked up a bit of rainfall Monday afternoon. Temperatures remained
quite mild with readings in the lower-middle 70s. Expect quiet
weather to continue through the remainder of the overnight hours
with overnight minimums dropping only a few more degrees or so.
For Today/Tonight, the short term multi-model consensus continues to
be in agreement with increasing the strength of the mid-level ridge
axis overhead. This should result in another mostly sunny and muggy
day across the region. With some additional mid-level warming and
slight drying of the column, current thinking is that convection
will be a bit more isolated. However, high resolution convective
allowing models suggest that storms will fire up to our north along
the periphery of the ridge axis. These could slide southward in the
afternoon and affect our far northern areas of southern Indiana.
Thus, have maintained an isolated storm chance up that way for the
late afternoon hours. Afternoon highs will be similar to Monday
with readings in the upper 80s to the lower 90s. Skies are expected
to clear back out tonight as any convection dissipates after
sunset. Overnight lows will cool into the upper 60s in the far NE
to the lower 70s in the central and southwest.
For Wednesday, the upper level ridge axis is expected to shift a bit
further to the south along with the surface ridge axis. This will
allow a surface frontal boundary to sag southward through central
Indiana. Convection is expected to develop during the afternoon
hours along this front and this activity may eventually spread
southward into southern Indiana and the northern half of KY. For
now, isolated-scattered PoPs still look like a good bet at this
time. Afternoon highs will be warm once again with readings topping
out in the upper 80s in the north with lower 90s in the south.
.LONG TERM (Wednesday Night through Monday)...
Issued at 307 AM EDT Tue Aug 26 2014
Ridging across the southeastern United States will slowly shift
eastward through the long term. As it does so a shortwave trough
will approach from the west, moving across the upper Midwest Sunday
and across the Great Lakes region by Monday morning. At the surface
a weak frontal boundary near the KY/TN border at the beginning of
the period will eventually push back northward as a warm front
Friday.
For Wednesday night a few residual showers or storms may be ongoing
at the start of the period. However, these should dissipate
overnight with mostly dry conditions expected. Diurnal storms are
expected once again on Thursday and Friday, particularly in the
vicinity of the frontal boundaries. The better chance will be on
Thursday with scattered storms across the region. Friday`s storms
look to be more isolated in nature.
Rain chances will increase through the weekend as the upper level
trough nears and its associated surface low lifts north of the
region. The best chances for storms this weekend looks to be on
Sunday as precipitable water values rise to around 1.9 inches and we
become moderately unstable. Will keep chances in the 40-50% range
right now considering there is still some differences in the
development of the system between the model solutions. Monday will
see a return to the more summertime diurnal pattern of storms before
a cold front approaches towards midweek.
Temperatures will be in the upper 80s to lower 90s through Saturday
with lows in the upper 60s to lower 70s. With rain and clouds
expected Sunday into Monday we should see a bit of a cool down,
particularly on Sunday with highs in the lower to mid 80s expected.
This will not last however, as a return to upper 80s is expected by
Tuesday.
&&
.AVIATION (12Z TAF Update)...
Issued at 650 AM EDT Tue Aug 26 2014
Other than a period of VLIFR/LIFR at KBWG due to locally dense fog,
VFR conditions are expected at the terminals through the upcoming
period. Expect visibilities to return back to VFR at KBWG by
26/14Z. Elsewhere, mostly sunny skies and light northeast winds
will be seen at the terminals. Some isolated convection will be
possible this afternoon...mainly across southern Indiana. These may
threaten the KSDF terminal this afternoon...but the expected sparse
coverage precludes a mention in the TAF at this time.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........BJS
Short Term.....MJ
Long Term......EER
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
255 PM CDT TUE AUG 26 2014
.DISCUSSION...
ISOLD SHWRS/TSTMS NOTED ON KSHV RADAR THIS AFTN. WHILE THE TUTT
CONTINUES TO STIR UP SLIGHTLY MORE ORGANIZED CONVECTION ACROSS THE
NRN GULF COAST...IT IS HAVING DECIDEDLY LESS INFLUENCE ACROSS OUR
REGION TODAY VERSUS MONDAY. AT ANY RATE...THE WEAKNESS IN THE
UPPER RIDGE IS MAKING FOR COOLER TEMPS TODAY.
A DRIER AIRMASS IS EXPECTED TO MOVE INTO THE REGION OVERNIGHT...
WHICH WILL ALLOW FOR VERY EFFECTIVE MIXING DURING WEDNESDAY AFTN.
WHILE TEMPS ARE EXPECTED TO WARM INTO THE MID 90S...DEW POINTS AS
LOW AS 60 DEGREES WILL BE POSSIBLE...WHICH WILL KEEP OUR HEAT
INDEX VALUES BELOW 100 DEGREES FOR THE FIRST TIME IN SEVERAL DAYS.
CHANCES FOR ISOLD CONVECTION WILL PICK BACK UP THURSDAY...AS THE
UPPER RIDGE BEGINS TO BE FORCED EWD BY AN APPROACHING TROF. MODELS
IN GOOD AGREEMENT FOR AN INCREASE IN RAIN CHANCES INTO FRIDAY AND
SATURDAY...AS THE TROF BEGINS TO MOVE ACROSS THE PLAINS AND INTO
THE MS RIVER VALLEY. WHILE THE UPPER TROF IS FCST TO DAMPEN/MOVE
EWD SUNDAY INTO EARLY NEXT WEEK...SLIGHTLY ENHANCED RAIN CHANCES
ARE EXPECTED TO LINGER IN THE ABSENCE OF THE UPPER RIDGE...WHICH
WILL CONTINUE TO HANG OUT OVER THE E COAST OF THE U.S. AS A RESULT
OF CONVECTION/CLOUD COVER...TEMPS WILL RUN NEAR OR EVEN SLIGHTLY
BELOW NORMAL THROUGH THE EXTENDED. /12/
&&
AVIATION... LATEST VIS IMAGERY THIS MORNING SHOWS OUR INVERTED
TROUGH OR TUTT LOW ACROSS THE S LA COAST...NOT LOOKING NEARLY AS
DEFINED AS WAS THE CASE THIS TIME ON MONDAY. 12Z NAM OUTPUT NOT
NEARLY AS SUPPORTIVE OF PRECIP COVERAGE TODAY COMPARED TO PREVIOUS
RUNS. HAVING SAID THAT...LATEST HRRR STILL SUGGESTS ISOLATED
CONVECTION DEVELOPING BY EARLY AFTERNOON ACROSS PORTIONS OF THE
REGION BUT THE KEY WORD IS ISOLATED.
FOR THE 18Z TAF PACKAGE...WILL NOT MAKE MENTION OF VCSH/VCTS AS
COVERAGE WILL JUST BE TOO SPARSE. CU FIELD SHOULD DEVELOP OVER THE
NEXT COUPLE HOURS WITH HEIGHTS RANGING FROM 4-6KFT THROUGH THE
AFTERNOON. CU FIELD SHOULD QUICKLY DISSIPATE AFTER SUNSET.
KEPT MENTION OF PATCHY FOG IN AT THE MLU TERMINAL OVERNIGHT BUT
MUCH DRIER AIR FILTERING IN FROM THE EAST MAY DETOUR THAT FROM
OCCURRING. /13/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 95 74 94 76 / 10 10 10 20 20
MLU 69 94 71 93 73 / 10 10 10 20 20
DEQ 71 93 69 91 71 / 10 10 10 20 20
TXK 72 93 70 92 73 / 10 10 10 20 20
ELD 69 93 68 91 71 / 10 10 10 20 20
TYR 73 96 75 95 76 / 10 10 10 20 20
GGG 71 96 73 94 74 / 10 10 10 20 20
LFK 74 96 75 95 76 / 10 20 10 30 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1040 AM CDT TUE AUG 26 2014
.DISCUSSION...
WV IMAGERY CLEARLY DEPICTS THE TUTT CURRENTLY CHURNING ACROSS THE
NRN GULF COAST. THIS DISTURBANCE MAY HELP TO KICK OFF SOME
CONVECTION THIS AFTN...ALTHOUGH MODELS NOT DEPICTING MUCH IN THE
WAY OF COVERAGE. CONSIDERING THE LACK OF CU DEVELOPMENT ACROSS
MUCH OF THE REGION THUS FAR...HAVE LOWERED THE 30 POPS ACROSS DEEP
E TX TO 20S. HAVE ALSO TWEAKED THE SKY GRIDS...BUT OTHERWISE...THE
GRIDS ARE IN GOOD SHAPE. /12/
&&
AVIATION... LATEST VIS IMAGERY THIS MORNING SHOWS OUR INVERTED
TROUGH OR TUTT LOW ACROSS THE S LA COAST...NOT LOOKING NEARLY AS
DEFINED AS WAS THE CASE THIS TIME ON MONDAY. 12Z NAM OUTPUT NOT
NEARLY AS SUPPORTIVE OF PRECIP COVERAGE TODAY COMPARED TO PREVIOUS
RUNS. HAVING SAID THAT...LATEST HRRR STILL SUGGESTS ISOLATED
CONVECTION DEVELOPING BY EARLY AFTERNOON ACROSS PORTIONS OF THE
REGION BUT THE KEY WORD IS ISOLATED.
FOR THE 18Z TAF PACKAGE...WILL NOT MAKE MENTION OF VCSH/VCTS AS
COVERAGE WILL JUST BE TOO SPARSE. CU FIELD SHOULD DEVELOP OVER THE
NEXT COUPLE HOURS WITH HEIGHTS RANGING FROM 4-6KFT THROUGH THE
AFTERNOON. CU FIELD SHOULD QUICKLY DISSIPATE AFTER SUNSET.
KEPT MENTION OF PATCHY FOG IN AT THE MLU TERMINAL OVERNIGHT BUT
MUCH DRIER AIR FILTERING IN FROM THE EAST MAY DETOUR THAT FROM
OCCURRING. /13/
PREV DISCUSSION... /ISSUED 435 AM CDT TUE AUG 26 2014/
DISCUSSION...
CENTER OF THE UPPER RIDGE WILL REMAIN ANCHORED TO OUR NORTH TODAY
WITH A WEAK SHEAR AXIS STILL IN PLACE OVER OUR REGION WHERE A WWD
MOVING UPPER DISTURBANCE BROUGHT SHWRS AND TSTMS TO PARTS OF N LA
YESTERDAY. THE RIDGE WILL CONTINUE TO BE THE PRIMARY INFLUENCE ON
OUR WEATHER FOR THE SHORT TERM BUT EXPECT ANOTHER DAY OF WIDELY
SCATTERED CONVECTION...AS THE WEAK CENTER OF CIRCULATION WITH THE
UPPER LOW OFF THE SE LA COAST SLOWLY MEANDERS WWD ACROSS THE NRN
GULF. BASED ON THE PLACEMENT OF THESE UPPER LEVEL FEATURES...THE
BEST CHANCES FOR SEEING ANY PASSING SHWRS OR ISOLD TSTMS WILL BE
SOUTH OF THE I-30 CORRIDOR AND MORE SO ACROSS DEEP E TX INTO W
CNTRL LA WHERE LOW CHANCE POPS ARE STILL ALL WE CAN MANAGE ATTM.
TEMPERATURES WILL CONTINUE TO HOVER IN THE MID 90S FOR HIGHS OVER
THE NEXT FEW DAYS UNTIL THE RIDGE FINALLY BEGINS TO BREAK DOWN AND
SLIDE EWD ALONG THE SE COAST TOWARD THE END OF THE WORK WEEK.
THIS WILL HELP TO INCREASE SOUTHERLY FLOW OFF THE GULF AND
INCREASE OUR RAIN CHANCES BY THURSDAY AND ESPECIALLY INTO FRIDAY
AND THE WEEKEND AS A LONGWAVE TROF SHIFTS EWD FROM THE PLAINS.
HAVE MAINTAINED POPS IN THE CHANCE CATEGORY FOR NOW WITH THIS
SYSTEM BUT WILL LIKELY NEED TO GO HIGHER AS BETTER CONSENSUS IS
REACHED WITH THE LONG TERM PROGS...WHICH HAVE COME INTO BETTER
AGREEMENT ALTHOUGH THE ECMWF IS STILL A BIT WETTER THAN THE GFS
WITH QPF AMOUNTS. AT A MINIMUM...WE CAN EXPECT SOME BENEFICIAL
RAINFALL AND TEMPERATURES RETURNING TO SEASONAL AVERAGES THROUGH
THE END OF THE EXTENDED PERIOD. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 96 72 96 72 95 / 20 20 10 10 20
MLU 94 68 95 70 94 / 20 10 10 10 20
DEQ 94 71 95 69 93 / 20 10 10 10 20
TXK 94 72 95 69 93 / 20 10 10 10 20
ELD 94 69 96 68 94 / 20 10 10 10 20
TYR 96 74 96 73 95 / 20 20 10 10 20
GGG 96 71 96 73 95 / 20 20 10 10 20
LFK 95 73 96 74 94 / 20 20 20 10 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1018 AM CDT TUE AUG 26 2014
.AVIATION...
LATEST VIS IMAGERY THIS MORNING SHOWS OUR INVERTED TROUGH OR TUTT
LOW ACROSS THE S LA COAST...NOT LOOKING NEARLY AS DEFINED AS WAS
THE CASE THIS TIME ON MONDAY. 12Z NAM OUTPUT NOT NEARLY AS
SUPPORTIVE OF PRECIP COVERAGE TODAY COMPARED TO PREVIOUS RUNS.
HAVING SAID THAT...LATEST HRRR STILL SUGGESTS ISOLATED CONVECTION
DEVELOPING BY EARLY AFTERNOON ACROSS PORTIONS OF THE REGION BUT
THE KEY WORD IS ISOLATED.
FOR THE 18Z TAF PACKAGE...WILL NOT MAKE MENTION OF VCSH/VCTS AS
COVERAGE WILL JUST BE TOO SPARSE. CU FIELD SHOULD DEVELOP OVER THE
NEXT COUPLE HOURS WITH HEIGHTS RANGING FROM 4-6KFT THROUGH THE
AFTERNOON. CU FIELD SHOULD QUICKLY DISSIPATE AFTER SUNSET.
KEPT MENTION OF PATCHY FOG IN AT THE MLU TERMINAL OVERNIGHT BUT
MUCH DRIER AIR FILTERING IN FROM THE EAST MAY DETOUR THAT FROM
OCCURRING.
13
&&
PREV DISCUSSION... /ISSUED 435 AM CDT TUE AUG 26 2014/
DISCUSSION...
CENTER OF THE UPPER RIDGE WILL REMAIN ANCHORED TO OUR NORTH TODAY
WITH A WEAK SHEAR AXIS STILL IN PLACE OVER OUR REGION WHERE A WWRD
MOVING UPPER DISTURBANCE BROUGHT SHWRS AND TSTMS TO PARTS OF N LA
YESTERDAY. THE RIDGE WILL CONTINUE TO BE THE PRIMARY INFLUENCE ON
OUR WEATHER FOR THE SHORT TERM BUT EXPECT ANOTHER DAY OF WIDELY
SCATTERED CONVECTION...AS THE WEAK CENTER OF CIRCULATION WITH THE
UPPER LOW OFF THE SE LA COAST SLOWLY MEANDERS WWRD ACROSS THE NRN
GULF. BASED ON THE PLACEMENT OF THESE UPPER LEVEL FEATURES...THE
BEST CHANCES FOR SEEING ANY PASSING SHWRS OR ISOLD TSTMS WILL BE
SOUTH OF THE I-30 CORRIDOR AND MORE SO ACROSS DEEP E TX INTO W
CNTRL LA WHERE LOW CHANCE POPS ARE STILL ALL WE CAN MANAGE ATTM.
TEMPERATURES WILL CONTINUE TO HOVER IN THE MID 90S FOR HIGHS OVER
THE NEXT FEW DAYS UNTIL THE RIDGE FINALLY BEGINS TO BREAK DOWN AND
SLIDE EWRD ALONG THE SE COAST TOWARD THE END OF THE WORK WEEK.
THIS WILL HELP TO INCREASE SOUTHERLY FLOW OFF THE GULF AND
INCREASE OUR RAIN CHANCES BY THURSDAY AND ESPECIALLY INTO FRIDAY
AND THE WEEKEND AS A LONGWAVE TROF SHIFTS EWRD FROM THE PLAINS.
HAVE MAINTAINED POPS IN THE CHANCE CATEGORY FOR NOW WITH THIS
SYSTEM BUT WILL LIKELY NEED TO GO HIGHER AS BETTER CONSENSUS IS
REACHED WITH THE LONG TERM PROGS...WHICH HAVE COME INTO BETTER
AGREEMENT ALTHOUGH THE ECMWF IS STILL A BIT WETTER THAN THE GFS
WITH QPF AMOUNTS. AT A MINIMUM...WE CAN EXPECT SOME BENEFICIAL
RAINFALL AND TEMPERATURES RETURNING TO SEASONAL AVERAGES THROUGH
THE END OF THE EXTENDED PERIOD. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 96 72 96 72 95 / 20 20 10 10 20
MLU 94 68 95 70 94 / 20 10 10 10 20
DEQ 94 71 95 69 93 / 20 10 10 10 20
TXK 94 72 95 69 93 / 20 10 10 10 20
ELD 94 69 96 68 94 / 20 10 10 10 20
TYR 96 74 96 73 95 / 20 20 10 10 20
GGG 96 71 96 73 95 / 20 20 10 10 20
LFK 95 73 96 74 94 / 30 20 20 10 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
13
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
126 PM EDT TUE AUG 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 501 AM EDT TUE AUG 26 2014
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...VIGOROUS SHORTWAVE THAT
WAS MOVING INTO SRN MANITOBA 24HRS AGO IS NOW MUCH WEAKER AND
TRACKING THRU NRN ONTARIO. ASSOCIATED COLD FRONT SWEPT ACROSS UPPER
MI DURING THE NIGHT...USHERING IN MUCH DRIER AIR. SFC DWPTS THAT
WERE IN THE 60S TO AROUND 70F ARE NOW DOWN IN THE MORE COMFORTABLE
50S AT NEARLY ALL LOCATIONS. UPSTREAM...QUITE A BIT OF CLOUD COVER IS
NOTED ACROSS THE NRN HALF OF MN...AND THERE HAVE EVEN BEEN A FEW
-SHRA/SPRINKLES IN NE MN. IN THE LAST FEW HRS...THE CLOUDS HAVE BEEN
THINNING OUT...AND RECENTLY THE CLOUDS HAVE SPREAD INTO WRN UPPER
MI. THESE CLOUDS ARE SITUATED IN THE 850MB THERMAL TROF WHICH HAS
850MB TEMPS AS LOW AS 4-5C OVER FAR NRN MN.
TODAY...850MB TROF SHIFTS INTO THE UPPER GREAT LAKES. WITH ONSET OF
DAYTIME HEATING COINCIDING WITH ARRIVAL OF THERMAL TROF...THERE
SHOULD BE AN EXPANSION OF SCT/BKN CU/STRATOCU FOR A TIME...
ESPECIALLY ACROSS THE N. DURING THE MID AND LATE AFTN...THE CLOUDS
SHOULD BEGIN TO DISSIPATE. FCST SOUNDINGS SUPPORT MAX TEMPS IN THE
UPPER 60S TO MID 70S...WARMEST SOUTH CENTRAL. WILL BE A BIT COOLER
WHERE WINDS ARE OFF LAKE SUPERIOR.
TONIGHT...SFC HIGH PRES BUILDS INTO THE WRN GREAT LAKES. HOWEVER...
SHORTWAVE TROF NOW OVER SASKATCHEWAN/MT IS FCST TO SHIFT E...
REACHING THE UPPER GREAT LAKES BY 12Z WED. SOME MODELS SHOW LIGHT
PCPN STREAKING E INTO WI AND EVEN INTO UPPER MI. INITIALLY...PCPN
DEVELOPMENT OUT OVER THE NRN PLAINS APPEARS TIED TO RIGHT ENTRANCE
OF JET STREAK ACROSS THE FAR NRN PLAINS. HOWEVER...WITH THE JET
TRANSLATING E OVER THE UPPER GREAT LAKES...JET FORCING WILL BE S OF
THE FCST AREA TONIGHT. IN ADDITION...LITTLE/NO DEEP LAYER FORCING IS
NOTED WITH SHORTWAVE...AND LOW-LEVELS ARE DRYING OUT TODAY. SO...IF
PCPN DOES MANAGE TO STREAK INTO THE AREA...THE LIGHT PCPN WOULD
LIKELY DRY UP BEFORE MAKING IT TO THE GROUND. THUS...NO MENTION OF
PCPN WAS INCLUDED IN FCST TONIGHT. AN INCREASE IN CLOUDS WILL KEEP
TEMPS FROM FALLING AS MUCH AS THEY COULD. OPTED FOR THE MIDDLE
GROUND OF AVBL GUIDANCE...RESULTING IN MIN TEMPS MOSTLY IN THE UPPER
40S/LWR 50S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 346 AM EDT TUE AUG 26 2014
A SHORTWAVE WILL BE SLIDING EAST ACROSS THE CENTRAL/EASTERN CWA TO
START THE LONG TERM PERIOD WITHIN THE WEST-NORTHWEST FLOW ALOFT.
THERE IS A LITTLE POCKET OF MOISTURE BETWEEN 700-500MB ASSOCIATED
WITH THIS WAVE THAT WILL TRY TO KICK OFF SOME SHOWERS OVER THE
EASTERN CWA FOR THE FIRST COUPLE HOURS ON WEDNESDAY MORNING. WITH
DRY AIR BELOW 700MB DUE TO HIGH PRESSURE CENTERED NEAR DULUTH AT
12Z WEDNESDAY...THINK ANY PRECIPITATION THAT OCCURS WILL EVAPORATE
BEFORE REACHING THE SURFACE. BEHIND THIS WAVE...UPPER RIDGING WILL
DEVELOP AND ALLOW THE HIGH TO SHIFT EAST ACROSS THE CWA THROUGH
THURSDAY MORNING. THIS DRY AIR WILL LEAD TO MOSTLY CLEAR SKIES
ACROSS MUCH OF THE CWA...BUT THERE COULD BE SOME DIURNAL CLOUD
DEVELOPMENT WEDNESDAY AFTERNOON (INLAND AND TOWARDS WISCONSIN
BORDER) AFTER THE MID CLOUDS DEPART DURING THE MORNING. HIGHS WILL
BE BELOW NORMAL ON WEDNESDAY SINCE 850MB TEMPS IN THE MODELS ARE
AVERAGING AROUND 6-7C AND KEEPING HIGHS IN THE MID-UPPER 60S FOR
MOST LOCATIONS. LOWS WEDNESDAY NIGHT COULD GET CHILLY WITH THE
LIGHT WINDS...CLEAR SKIES...AND PWAT VALUES ABOUT 50 PERCENT OF
NORMAL. TRENDED LOWS DOWN INTO THE LOWER 40S OVER THE INTERIOR
LOCATIONS...AND EVEN HAVE SOME UPPER 30S FOR THE TRADITIONAL COLD
RAWS SITES.
THE AREA OF HIGH PRESSURE WILL DRIFT TO THE EAST ON THURSDAY AS THE
FIRST OF A SERIES OF SHORTWAVES LIFTS NORTHEAST OUT OF THE CENTRAL
ROCKIES/PLAINS THURSDAY AFTERNOON INTO THURSDAY NIGHT. AS HAS BEEN
THE CASE FOR THE LAST COUPLE DAYS...SEEMS LIKE BEST OPPORTUNITY FOR
RAIN WILL BE OVER THE SOUTHEAST HALF OF THE CWA. THESE SHOWERS
COULD LINGER INTO FRIDAY OVER THE SAME AREA BEFORE THE NEXT WAVE
SLIDES NORTHEAST TOWARDS THE AREA ON FRIDAY NIGHT. ONCE
AGAIN...BEST CHANCES WILL BE OVER THE SOUTHEAST PART OF THE
AREA...BUT LIKELY MORE CONFINED TO NEAR THE LAKE MICHIGAN
SHORELINE. WHILE THAT WAVE IS MOVING THROUGH...A WEAK SURFACE
TROUGH WILL SLOWLY DROP SOUTHEAST ACROSS THE CWA ON SATURDAY. THINK
PRECIP CHANCES WITH THIS PASSING TROUGH WILL BE LIMITED DUE TO
SHALLOW MOISTURE AND LIMITED UPPER LEVEL SUPPORT...THUS WILL KEEP
POPS FOR MOST AREAS IN THE SLIGHT CHANCE CATEGORY. BEHIND THAT
TROUGH...A HIGH PRESSURE RIDGE WILL MOVE OVER THE CWA SATURDAY
NIGHT AND REMAIN THROUGH SUNDAY NIGHT...AS THE PARENT HIGH SLIDES
SOUTHEAST ACROSS NORTHERN ONTARIO.
A STRONGER UPPER TROUGH WILL APPROACH THE AREA FOR THE FIRST PART
OF NEXT WEEK. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS UPPER
TROUGH WILL BE MOVING THROUGH SOUTHERN CANADA AND ALLOW SOUTHERLY
FLOW TO INCREASE OVER THE AREA SUNDAY NIGHT INTO MONDAY. THIS WILL
LEAD TO ABOVE NORMAL TEMPERATURES ON MONDAY AHEAD OF THE COLD FRONT
THAT MOVES THROUGH MONDAY NIGHT INTO TUESDAY MORNING. WILL SHOW
INCREASING CHANCES FOR RAIN MONDAY INTO MONDAY NIGHT AS THE COLD
FRONT PASSES THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 122 PM EDT TUE AUG 26 2014
THERMAL TROUGH ALOFT RESULTS IN BKN MVFR TO LOWER VFR CLOUDS THIS
AFTN AT KCMX AND KSAW. PLAN ON THESE CLOUDS TO SCATTER OUT BY THE
EVENING AS RIDGING TRIES TO WORK INTO THE AREA. MID-LEVEL CLOUDS
WILL INCREASE FOR A TIME OVERNIGHT UNTIL AROUND DAYBREAK ON WEDNESDAY
AS DISTURBANCE CROSSES THE REGION. GUSTY WEST WINDS AT KCMX SHOULD
DIMINISH QUICKLY BY LATE THIS AFTN. OTHERWISE...EXPECT LIGHT WINDS
REST OF THE TAF PERIOD AT ALL TERMINALS. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 501 AM EDT TUE AUG 26 2014
EXPECT WESTERLY WINDS AS HIGH AS 15-25KT OVER MUCH OF LAKE SUPERIOR
TODAY...RESULTING FROM PRES GRADIENT BTWN LOW PRES WELL OFF TO THE
NE AND HIGH PRES APPROACHING FROM THE W. AS THE HIGH SETTLES OVER
THE UPPER GREAT LAKES LATER TONIGHT THRU EARLY THU...WINDS WILL DROP
OFF TO MOSTLY UNDER 15KT. ALTHOUGH THE HIGH PRES DEPARTS THU...WINDS
SHOULD REMAIN UNDER 20KT FRI/SAT EVEN WITH TROF DROPPING ACROSS THE
AREA EARLY SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
753 AM EDT TUE AUG 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 501 AM EDT TUE AUG 26 2014
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...VIGOROUS SHORTWAVE THAT
WAS MOVING INTO SRN MANITOBA 24HRS AGO IS NOW MUCH WEAKER AND
TRACKING THRU NRN ONTARIO. ASSOCIATED COLD FRONT SWEPT ACROSS UPPER
MI DURING THE NIGHT...USHERING IN MUCH DRIER AIR. SFC DWPTS THAT
WERE IN THE 60S TO AROUND 70F ARE NOW DOWN IN THE MORE COMFORTABLE
50S AT NEARLY ALL LOCATIONS. UPSTREAM...QUITE A BIT OF CLOUD COVER IS
NOTED ACROSS THE NRN HALF OF MN...AND THERE HAVE EVEN BEEN A FEW
-SHRA/SPRINKLES IN NE MN. IN THE LAST FEW HRS...THE CLOUDS HAVE BEEN
THINNING OUT...AND RECENTLY THE CLOUDS HAVE SPREAD INTO WRN UPPER
MI. THESE CLOUDS ARE SITUATED IN THE 850MB THERMAL TROF WHICH HAS
850MB TEMPS AS LOW AS 4-5C OVER FAR NRN MN.
TODAY...850MB TROF SHIFTS INTO THE UPPER GREAT LAKES. WITH ONSET OF
DAYTIME HEATING COINCIDING WITH ARRIVAL OF THERMAL TROF...THERE
SHOULD BE AN EXPANSION OF SCT/BKN CU/STRATOCU FOR A TIME...
ESPECIALLY ACROSS THE N. DURING THE MID AND LATE AFTN...THE CLOUDS
SHOULD BEGIN TO DISSIPATE. FCST SOUNDINGS SUPPORT MAX TEMPS IN THE
UPPER 60S TO MID 70S...WARMEST SOUTH CENTRAL. WILL BE A BIT COOLER
WHERE WINDS ARE OFF LAKE SUPERIOR.
TONIGHT...SFC HIGH PRES BUILDS INTO THE WRN GREAT LAKES. HOWEVER...
SHORTWAVE TROF NOW OVER SASKATCHEWAN/MT IS FCST TO SHIFT E...
REACHING THE UPPER GREAT LAKES BY 12Z WED. SOME MODELS SHOW LIGHT
PCPN STREAKING E INTO WI AND EVEN INTO UPPER MI. INITIALLY...PCPN
DEVELOPMENT OUT OVER THE NRN PLAINS APPEARS TIED TO RIGHT ENTRANCE
OF JET STREAK ACROSS THE FAR NRN PLAINS. HOWEVER...WITH THE JET
TRANSLATING E OVER THE UPPER GREAT LAKES...JET FORCING WILL BE S OF
THE FCST AREA TONIGHT. IN ADDITION...LITTLE/NO DEEP LAYER FORCING IS
NOTED WITH SHORTWAVE...AND LOW-LEVELS ARE DRYING OUT TODAY. SO...IF
PCPN DOES MANAGE TO STREAK INTO THE AREA...THE LIGHT PCPN WOULD
LIKELY DRY UP BEFORE MAKING IT TO THE GROUND. THUS...NO MENTION OF
PCPN WAS INCLUDED IN FCST TONIGHT. AN INCREASE IN CLOUDS WILL KEEP
TEMPS FROM FALLING AS MUCH AS THEY COULD. OPTED FOR THE MIDDLE
GROUND OF AVBL GUIDANCE...RESULTING IN MIN TEMPS MOSTLY IN THE UPPER
40S/LWR 50S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 346 AM EDT TUE AUG 26 2014
A SHORTWAVE WILL BE SLIDING EAST ACROSS THE CENTRAL/EASTERN CWA TO
START THE LONG TERM PERIOD WITHIN THE WEST-NORTHWEST FLOW ALOFT.
THERE IS A LITTLE POCKET OF MOISTURE BETWEEN 700-500MB ASSOCIATED
WITH THIS WAVE THAT WILL TRY TO KICK OFF SOME SHOWERS OVER THE
EASTERN CWA FOR THE FIRST COUPLE HOURS ON WEDNESDAY MORNING. WITH
DRY AIR BELOW 700MB DUE TO HIGH PRESSURE CENTERED NEAR DULUTH AT
12Z WEDNESDAY...THINK ANY PRECIPITATION THAT OCCURS WILL EVAPORATE
BEFORE REACHING THE SURFACE. BEHIND THIS WAVE...UPPER RIDGING WILL
DEVELOP AND ALLOW THE HIGH TO SHIFT EAST ACROSS THE CWA THROUGH
THURSDAY MORNING. THIS DRY AIR WILL LEAD TO MOSTLY CLEAR SKIES
ACROSS MUCH OF THE CWA...BUT THERE COULD BE SOME DIURNAL CLOUD
DEVELOPMENT WEDNESDAY AFTERNOON (INLAND AND TOWARDS WISCONSIN
BORDER) AFTER THE MID CLOUDS DEPART DURING THE MORNING. HIGHS WILL
BE BELOW NORMAL ON WEDNESDAY SINCE 850MB TEMPS IN THE MODELS ARE
AVERAGING AROUND 6-7C AND KEEPING HIGHS IN THE MID-UPPER 60S FOR
MOST LOCATIONS. LOWS WEDNESDAY NIGHT COULD GET CHILLY WITH THE
LIGHT WINDS...CLEAR SKIES...AND PWAT VALUES ABOUT 50 PERCENT OF
NORMAL. TRENDED LOWS DOWN INTO THE LOWER 40S OVER THE INTERIOR
LOCATIONS...AND EVEN HAVE SOME UPPER 30S FOR THE TRADITIONAL COLD
RAWS SITES.
THE AREA OF HIGH PRESSURE WILL DRIFT TO THE EAST ON THURSDAY AS THE
FIRST OF A SERIES OF SHORTWAVES LIFTS NORTHEAST OUT OF THE CENTRAL
ROCKIES/PLAINS THURSDAY AFTERNOON INTO THURSDAY NIGHT. AS HAS BEEN
THE CASE FOR THE LAST COUPLE DAYS...SEEMS LIKE BEST OPPORTUNITY FOR
RAIN WILL BE OVER THE SOUTHEAST HALF OF THE CWA. THESE SHOWERS
COULD LINGER INTO FRIDAY OVER THE SAME AREA BEFORE THE NEXT WAVE
SLIDES NORTHEAST TOWARDS THE AREA ON FRIDAY NIGHT. ONCE
AGAIN...BEST CHANCES WILL BE OVER THE SOUTHEAST PART OF THE
AREA...BUT LIKELY MORE CONFINED TO NEAR THE LAKE MICHIGAN
SHORELINE. WHILE THAT WAVE IS MOVING THROUGH...A WEAK SURFACE
TROUGH WILL SLOWLY DROP SOUTHEAST ACROSS THE CWA ON SATURDAY. THINK
PRECIP CHANCES WITH THIS PASSING TROUGH WILL BE LIMITED DUE TO
SHALLOW MOISTURE AND LIMITED UPPER LEVEL SUPPORT...THUS WILL KEEP
POPS FOR MOST AREAS IN THE SLIGHT CHANCE CATEGORY. BEHIND THAT
TROUGH...A HIGH PRESSURE RIDGE WILL MOVE OVER THE CWA SATURDAY
NIGHT AND REMAIN THROUGH SUNDAY NIGHT...AS THE PARENT HIGH SLIDES
SOUTHEAST ACROSS NORTHERN ONTARIO.
A STRONGER UPPER TROUGH WILL APPROACH THE AREA FOR THE FIRST PART
OF NEXT WEEK. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS UPPER
TROUGH WILL BE MOVING THROUGH SOUTHERN CANADA AND ALLOW SOUTHERLY
FLOW TO INCREASE OVER THE AREA SUNDAY NIGHT INTO MONDAY. THIS WILL
LEAD TO ABOVE NORMAL TEMPERATURES ON MONDAY AHEAD OF THE COLD FRONT
THAT MOVES THROUGH MONDAY NIGHT INTO TUESDAY MORNING. WILL SHOW
INCREASING CHANCES FOR RAIN MONDAY INTO MONDAY NIGHT AS THE COLD
FRONT PASSES THROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 752 AM EDT TUE AUG 26 2014
SOME LOWER CLOUDS ARE ACCOMPANYING THERMAL TROF INTO THE UPPER
LAKES...AND THIS WILL YIELD OCNL MVFR CIGS AT KIWD/KSAW FOR THE NEXT
2-3 HRS. THEREAFTER...DAYTIME HEATING WILL HELP TO RAISE CLOUD
BASES...LEADING TO VFR CONDITIONS PREVAILING. VFR CONDITIONS WILL
PREVAIL AT KCMX THRU THE FCST PERIOD. GUSTY W WINDS WILL ALSO
CONTINUE AT KCMX TODAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 501 AM EDT TUE AUG 26 2014
EXPECT WESTERLY WINDS AS HIGH AS 15-25KT OVER MUCH OF LAKE SUPERIOR
TODAY...RESULTING FROM PRES GRADIENT BTWN LOW PRES WELL OFF TO THE
NE AND HIGH PRES APPROACHING FROM THE W. AS THE HIGH SETTLES OVER
THE UPPER GREAT LAKES LATER TONIGHT THRU EARLY THU...WINDS WILL DROP
OFF TO MOSTLY UNDER 15KT. ALTHOUGH THE HIGH PRES DEPARTS THU...WINDS
SHOULD REMAIN UNDER 20KT FRI/SAT EVEN WITH TROF DROPPING ACROSS THE
AREA EARLY SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
501 AM EDT TUE AUG 26 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 501 AM EDT TUE AUG 26 2014
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...VIGOROUS SHORTWAVE THAT
WAS MOVING INTO SRN MANITOBA 24HRS AGO IS NOW MUCH WEAKER AND
TRACKING THRU NRN ONTARIO. ASSOCIATED COLD FRONT SWEPT ACROSS UPPER
MI DURING THE NIGHT...USHERING IN MUCH DRIER AIR. SFC DWPTS THAT
WERE IN THE 60S TO AROUND 70F ARE NOW DOWN IN THE MORE COMFORTABLE
50S AT NEARLY ALL LOCATIONS. UPSTREAM...QUITE A BIT OF CLOUD COVER IS
NOTED ACROSS THE NRN HALF OF MN...AND THERE HAVE EVEN BEEN A FEW
-SHRA/SPRINKLES IN NE MN. IN THE LAST FEW HRS...THE CLOUDS HAVE BEEN
THINNING OUT...AND RECENTLY THE CLOUDS HAVE SPREAD INTO WRN UPPER
MI. THESE CLOUDS ARE SITUATED IN THE 850MB THERMAL TROF WHICH HAS
850MB TEMPS AS LOW AS 4-5C OVER FAR NRN MN.
TODAY...850MB TROF SHIFTS INTO THE UPPER GREAT LAKES. WITH ONSET OF
DAYTIME HEATING COINCIDING WITH ARRIVAL OF THERMAL TROF...THERE
SHOULD BE AN EXPANSION OF SCT/BKN CU/STRATOCU FOR A TIME...
ESPECIALLY ACROSS THE N. DURING THE MID AND LATE AFTN...THE CLOUDS
SHOULD BEGIN TO DISSIPATE. FCST SOUNDINGS SUPPORT MAX TEMPS IN THE
UPPER 60S TO MID 70S...WARMEST SOUTH CENTRAL. WILL BE A BIT COOLER
WHERE WINDS ARE OFF LAKE SUPERIOR.
TONIGHT...SFC HIGH PRES BUILDS INTO THE WRN GREAT LAKES. HOWEVER...
SHORTWAVE TROF NOW OVER SASKATCHEWAN/MT IS FCST TO SHIFT E...
REACHING THE UPPER GREAT LAKES BY 12Z WED. SOME MODELS SHOW LIGHT
PCPN STREAKING E INTO WI AND EVEN INTO UPPER MI. INITIALLY...PCPN
DEVELOPMENT OUT OVER THE NRN PLAINS APPEARS TIED TO RIGHT ENTRANCE
OF JET STREAK ACROSS THE FAR NRN PLAINS. HOWEVER...WITH THE JET
TRANSLATING E OVER THE UPPER GREAT LAKES...JET FORCING WILL BE S OF
THE FCST AREA TONIGHT. IN ADDITION...LITTLE/NO DEEP LAYER FORCING IS
NOTED WITH SHORTWAVE...AND LOW-LEVELS ARE DRYING OUT TODAY. SO...IF
PCPN DOES MANAGE TO STREAK INTO THE AREA...THE LIGHT PCPN WOULD
LIKELY DRY UP BEFORE MAKING IT TO THE GROUND. THUS...NO MENTION OF
PCPN WAS INCLUDED IN FCST TONIGHT. AN INCREASE IN CLOUDS WILL KEEP
TEMPS FROM FALLING AS MUCH AS THEY COULD. OPTED FOR THE MIDDLE
GROUND OF AVBL GUIDANCE...RESULTING IN MIN TEMPS MOSTLY IN THE UPPER
40S/LWR 50S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 346 AM EDT TUE AUG 26 2014
A SHORTWAVE WILL BE SLIDING EAST ACROSS THE CENTRAL/EASTERN CWA TO
START THE LONG TERM PERIOD WITHIN THE WEST-NORTHWEST FLOW ALOFT.
THERE IS A LITTLE POCKET OF MOISTURE BETWEEN 700-500MB ASSOCIATED
WITH THIS WAVE THAT WILL TRY TO KICK OFF SOME SHOWERS OVER THE
EASTERN CWA FOR THE FIRST COUPLE HOURS ON WEDNESDAY MORNING. WITH
DRY AIR BELOW 700MB DUE TO HIGH PRESSURE CENTERED NEAR DULUTH AT
12Z WEDNESDAY...THINK ANY PRECIPITATION THAT OCCURS WILL EVAPORATE
BEFORE REACHING THE SURFACE. BEHIND THIS WAVE...UPPER RIDGING WILL
DEVELOP AND ALLOW THE HIGH TO SHIFT EAST ACROSS THE CWA THROUGH
THURSDAY MORNING. THIS DRY AIR WILL LEAD TO MOSTLY CLEAR SKIES
ACROSS MUCH OF THE CWA...BUT THERE COULD BE SOME DIURNAL CLOUD
DEVELOPMENT WEDNESDAY AFTERNOON (INLAND AND TOWARDS WISCONSIN
BORDER) AFTER THE MID CLOUDS DEPART DURING THE MORNING. HIGHS WILL
BE BELOW NORMAL ON WEDNESDAY SINCE 850MB TEMPS IN THE MODELS ARE
AVERAGING AROUND 6-7C AND KEEPING HIGHS IN THE MID-UPPER 60S FOR
MOST LOCATIONS. LOWS WEDNESDAY NIGHT COULD GET CHILLY WITH THE
LIGHT WINDS...CLEAR SKIES...AND PWAT VALUES ABOUT 50 PERCENT OF
NORMAL. TRENDED LOWS DOWN INTO THE LOWER 40S OVER THE INTERIOR
LOCATIONS...AND EVEN HAVE SOME UPPER 30S FOR THE TRADITIONAL COLD
RAWS SITES.
THE AREA OF HIGH PRESSURE WILL DRIFT TO THE EAST ON THURSDAY AS THE
FIRST OF A SERIES OF SHORTWAVES LIFTS NORTHEAST OUT OF THE CENTRAL
ROCKIES/PLAINS THURSDAY AFTERNOON INTO THURSDAY NIGHT. AS HAS BEEN
THE CASE FOR THE LAST COUPLE DAYS...SEEMS LIKE BEST OPPORTUNITY FOR
RAIN WILL BE OVER THE SOUTHEAST HALF OF THE CWA. THESE SHOWERS
COULD LINGER INTO FRIDAY OVER THE SAME AREA BEFORE THE NEXT WAVE
SLIDES NORTHEAST TOWARDS THE AREA ON FRIDAY NIGHT. ONCE
AGAIN...BEST CHANCES WILL BE OVER THE SOUTHEAST PART OF THE
AREA...BUT LIKELY MORE CONFINED TO NEAR THE LAKE MICHIGAN
SHORELINE. WHILE THAT WAVE IS MOVING THROUGH...A WEAK SURFACE
TROUGH WILL SLOWLY DROP SOUTHEAST ACROSS THE CWA ON SATURDAY. THINK
PRECIP CHANCES WITH THIS PASSING TROUGH WILL BE LIMITED DUE TO
SHALLOW MOISTURE AND LIMITED UPPER LEVEL SUPPORT...THUS WILL KEEP
POPS FOR MOST AREAS IN THE SLIGHT CHANCE CATEGORY. BEHIND THAT
TROUGH...A HIGH PRESSURE RIDGE WILL MOVE OVER THE CWA SATURDAY
NIGHT AND REMAIN THROUGH SUNDAY NIGHT...AS THE PARENT HIGH SLIDES
SOUTHEAST ACROSS NORTHERN ONTARIO.
A STRONGER UPPER TROUGH WILL APPROACH THE AREA FOR THE FIRST PART
OF NEXT WEEK. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS UPPER
TROUGH WILL BE MOVING THROUGH SOUTHERN CANADA AND ALLOW SOUTHERLY
FLOW TO INCREASE OVER THE AREA SUNDAY NIGHT INTO MONDAY. THIS WILL
LEAD TO ABOVE NORMAL TEMPERATURES ON MONDAY AHEAD OF THE COLD FRONT
THAT MOVES THROUGH MONDAY NIGHT INTO TUESDAY MORNING. WILL SHOW
INCREASING CHANCES FOR RAIN MONDAY INTO MONDAY NIGHT AS THE COLD
FRONT PASSES THROUGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 129 AM EDT TUE AUG 26 2014
WITH DRIER AIR MOVING INTO THE AREA...VFR CONDITIONS WILL PREVAIL
THROUGH THE FCST PERIOD. WEST WINDS WILL REMAIN GUSTY AT
KCMX...ESPECIALLY AGAIN THIS MORNING WITH DAYTIME HEATING/MIXING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 501 AM EDT TUE AUG 26 2014
EXPECT WESTERLY WINDS AS HIGH AS 15-25KT OVER MUCH OF LAKE SUPERIOR
TODAY...RESULTING FROM PRES GRADIENT BTWN LOW PRES WELL OFF TO THE
NE AND HIGH PRES APPROACHING FROM THE W. AS THE HIGH SETTLES OVER
THE UPPER GREAT LAKES LATER TONIGHT THRU EARLY THU...WINDS WILL DROP
OFF TO MOSTLY UNDER 15KT. ALTHOUGH THE HIGH PRES DEPARTS THU...WINDS
SHOULD REMAIN UNDER 20KT FRI/SAT EVEN WITH TROF DROPPING ACROSS THE
AREA EARLY SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
327 PM CDT Tue Aug 26 2014
.SHORT TERM: (Through Late Tonight)
Issued at 324 PM CDT Tue Aug 26 2014
A fairly well-defined convergence zone extends along an axis from
Champaign through St. Louis towards Springfield this afternoon
associated with an old convective boundary. SBCAPE is over 4000
j/kg with little CIN along this corridor, and scattered storms
were noted along portions of the boundary. Short range HRRR and
RAP guidance suggests some of this activity may linger past sunset
and thus have included some low pops within the region. Otherwise the
other threat of showers and thunderstorms tonight will shift
northward along and north of the real east-west frontal boundary
which will be drapped across northern KS and northern MO into
central IL, mainly late tonight.
Glass
.LONG TERM: (Wednesday through Next Tuesday)
Issued at 324 PM CDT Tue Aug 26 2014
The east-west frontal boundary will gradually sink southward
throughout the day Wednesday settling into southern MO and
southern IL by early evening. Very unstable conditions due to
daytime heating and high dew points will persist and maintain a
threat of scattered showers and thunderstorms will the front, and
just to its north. Present indications are that overall the
atmosphere will be slightly cooler in the low-mid levels. This
cooling along with the front and attendant clouds/precipitation
are expected to diminish the magnitude of the recent heat. However
despite slightly cooler temperatures, the pooling of surface dew
points in the 70s will continue to produce afternoon heat index
values of 100-105 degrees along and south of a Columbia to
Litchfield line. I have extended the heat advisories and warnings
in this region, while the excessive heat appears to be over across
northern MO and central IL where cooler conditions have also been
noted today.
The east-west front is expected to retreat back northward on
Thursday as an upper trof migrates out of the Rockies and the
associated surface low lifts northeastward. The highest pops will
remain along and north of the retreating boundary, primarily
northern sections of the CWA Thursday-Thursday night. Heat is a tough
call on Thursday and the current forecast calls for highs in the
upper 80s to lower 90s. There could potentially be some lingering
pockets of afternoon HI values of 100+ but there is too much
uncertainty to extend any heat headlines to this time period.
The heat should definitely come to an end by the weekend. The models
move the upper trof from the Plains on Friday into and through the
MS Valley by late Sunday. A good chance of showers and thunderstorms
will accompany this trof and the attendant frontal system, with
cooler temperatures closer to normal for this time of year.
Glass
&&
.AVIATION: (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1218 PM CDT Tue Aug 26 2014
Specifics for KCOU, KUIN: The outflow boundary which produced
brief periods of IFR-MVFR cigs earlier today has pushed south of
the terminals. VFR conditions are expected for the remainder of
the afternoon unless an isolated thunderstom develops during peak
heating. Overnight convection is possible at KUIN, but confidence
is too low to include in the TAF at this time.
Specifics for KSTL, KSUS, KCPS: VFR for most of the period. Will
continue to monitor for SH/TS development during peak heating due
to the outflow boundary near the St. Louis metro area terminals.
Overnight convection which is expected to develop north of the
terminals may sink farther south than currently anticipated.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...HEAT ADVISORY until 8 PM CDT Wednesday FOR Audrain MO-Boone MO-
Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
Iron MO-Madison MO-Moniteau MO-Montgomery MO-Osage MO-
Reynolds MO-St. Francois MO-Ste. Genevieve MO-Warren MO-
Washington MO.
EXCESSIVE HEAT WARNING until 8 PM CDT Wednesday FOR Jefferson MO-
Lincoln MO-St. Charles MO-St. Louis City MO-St. Louis MO.
EXCESSIVE HEAT WARNING until 8 PM CDT this evening FOR Pike MO.
HEAT ADVISORY until 8 PM CDT this evening FOR Monroe MO-Ralls MO.
IL...EXCESSIVE HEAT WARNING until 8 PM CDT Wednesday FOR Bond IL-
Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Randolph IL-St. Clair IL-Washington IL.
EXCESSIVE HEAT WARNING until 8 PM CDT this evening FOR Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
959 PM CDT WED AUG 27 2014
.UPDATE...
ISSUED AT 954 PM CDT WED AUG 27 2014
SOME POP CHANGES FROM NEIGHBORING OFFICES THIS EVENING...MAINLY TO
SLOW DOWN ADVANCE OF PRECIP CHANCES NORTHWARD INTO SE ND/WCNTRL
MN. WENT ALONG WITH CHANGES. AGREES WITH RADAR AND LATEST HRRR AS
WELL. MID LEVEL MOISTURE SPREADING EAST-NORTHEAST THRU SE ND AS
EXPECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 305 PM CDT WED AUG 27 2014
NEXT CHANCE OF LIGHT RAIN WHICH ARRIVES LATER TONIGHT REMAINS THE
MAIN FORECAST CHALLENGE. MODELS HAVE BEEN BACK AND FORTH WITH THIS
FEATURE THE LAST COUPLE OF DAYS...ONE RUN PUSHING IT SOUTH OF THE
FA WHILE THE NEXT KEEPS IT THERE. TODAYS RUNS DO NOT ADD MUCH
CONFIDENCE TO THE RAIN FORECAST ACROSS THE SOUTH...SO WILL
GENERALLY STICK TO FORECAST CONTINUITY FOR NOW (WHICH KEEPS IT
IN). AS FOR LATE THIS AFTERNOON THE CUMULUS HAS BEEN THICKEST
ACROSS THE SOUTH WHILE IT HAS BEEN FADING OUT IN THE NORTH. LOOKS
LIKE THIS TREND WILL CONTINUE TONIGHT WHICH WILL RESULT IN WARMER
MIN TEMPS ACROSS THE SOUTH. THERE HAS BEEN FOG THE LAST COUPLE OF
NIGHTS...BUT ARE EXPECTING INCREASING CLOUDS ACROSS THE SOUTH. IF
ANY FOG FORMS TONIGHT IT MAY BE ACROSS THE NORTH. NOT SURE EXACTLY
WHEN ANY LIGHT SHOWERS WILL BREAK OUT ACROSS THE SOUTH AS EVEN THE
HIGH RESOLUTION MODELS DIFFER...SO WILL STICK WITH ITS ARRIVAL
COMING AFTER MIDNIGHT AND MAINLY ALONG AND SOUTH OF INTERSTATE 94.
12Z GFS IS THE MOST ROBUST AND FURTHEST NORTH WITH THE PCPN WHILE
OTHER MODELS ARE MUCH WEAKER...SO WILL GIVE THE LEAST WEIGHT TO
ITS SOLUTION. HOWEVER WILL EXPAND PCPN CHANCES A LITTLE FURTHER
NORTH FOR THURSDAY. WITH MORE CLOUDS/PCPN ACROSS THE SOUTH...HIGH
TEMPS WILL BE A LITTLE COOLER THERE. NEXT FRONTAL BOUNDARY WILL
ARRIVE LATE THU NIGHT IN THE NORTH BRINGING THE NEXT CHANCE FOR
PCPN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED AUG 27 2014
THE ABOVE MENTIONED FRONT WILL CONTINUE TO SLIDE SOUTH AND EAST ON
FRIDAY WITH PCPN CHANCES ALONG IT. HIGH PRESSURE SLIDES INTO THE
REGION LATER FRIDAY INTO SATURDAY ENDING ANY LINGERING PCPN
CHANCES.
FOR SAT NIGHT THROUGH WED...THE PERIOD SHOULD START OUT QUIET
ACTIVE...WITH MODELS IN GOOD AGREEMENT. A STRONG UPPER WAVE AND
FRONTAL BOUNDARY WILL MOVE THROUGH LATER SAT NIGHT THROUGH SUNDAY.
PWATS WILL RISE OVER 1.5 INCHES...WITH MLCAPES RISING OVER 1500 J/KG
IN THE EAST SUNDAY. WE EXPECT A ROUND OF SHOWERS AND STORMS WITH
ELEVATED CONVECTION SAT NIGHT INTO EARLY SUNDAY. MORE VIGOROUS SFC
BASED STORMS AND POSSIBLE STRONG/SEVERE STORMS ARE POSSIBLE
SUNDAY...DEPENDING ON TIMING OF WAVE AND FRONT. IT SHOULD BE MAINLY
DRY BY MONDAY THROUGH WED...WITH TEMPS NEAR NORMAL FOR EARLY
SEPTEMBER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 712 PM CDT WED AUG 27 2014
SCATTERED CIRRUS NORTHEASTERN ND/NW MN TONIGHT WITH INCREASING MID
CLOUDS OVERNIGHT IN SOUTHEASTERN ND/WCNTRL MN. MID CLOUDS THURSDAY
IN SE ND/WCNTRL MN WITH SPOTTY SHOWERS VS A THINNER HIGH CLOUD
DECK IN THE NORTH. WINDS GENERALLY SOUTH 5 TO 15 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/DK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1242 PM CDT TUE AUG 26 2014
.UPDATE...
ISSUED AT 1242 PM CDT TUE AUG 26 2014
THE LOW CLOUDS OVER NORTHWEST MN HAVE LIFTED INTO A STRATOCUMULUS
DECK WHICH IS STILL PRETTY THICK. WITH THE LOWER AMOUNT OF SOLAR
EXPECTED WILL GO AHEAD AND LOWER HIGH TEMPS THERE A BIT TOO.
OTHERWISE MORE CUMULUS ALSO FORMED FROM CANDO DOWN ACROSS THE
CENTRAL RED RIVER VALLEY INTO THE KPKD AREA...SO HAD TO BUMP UP
CLOUD AMOUNTS THERE TOO. SOME SHOWERS/ISOLATED THUNDER ARE ONGOING
ACROSS THE KDIK TO KBIS CORRIDOR AND THESE MAY WELL HOLD TOGETHER
AS THEY PROGRESS EASTWARD THRU THE LATER AFTERNOON. MAY HAVE TO
EXPAND THE LOW PCPN CHANCES NORTHWARD A BIT INTO THE CENTRAL RED
RIVER VALLEY IF THESE CONTINUE ON THEIR CURRENT PATH.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
TODAY...SURFACE HIGH PRESSURE CONTINUES TO PRESS OVER THE AREA
PRODUCING LIGHT WEST TO NORTHWEST FLOW...DRYING CONDITIONS AND
UNSEASONABLY COOL TEMPERATURES. RESIDUAL LOW CLOUDS ACROSS
NORTHERN MINNESOTA SHOULD SHIFT EASTWARD THROUGH THE MORNING AS
THE PARENT LOW PRESSURE SYSTEM CONTINUES ITS FAST BREAK ACROSS
NORTHERN ONTARIO AND JAMES BAY. EXPECT GENERALLY FAIR SKIES ACROSS
MOST OF THE AREA THROUGH MIDDAY TODAY...WITH INCREASING MIDDLE TO
LOWER LEVEL MOISTURE MOVING FROM NCNTRL SD INTO SOUTHEAST ND AND
WEST CENTRAL MN THROUGH THE LATER AFTERNOON. AN ISOLATED SHOWER OR
TWO IS POSSIBLE LATE THIS AFTERNOON ACROSS FAR SOUTHERN PORTIONS
OF THE RED RIVER BASIN. FOR NOW...THE RUC SEEMS A BIT OVERLY
AGGRESSIVE WIT THIS FEATURE...WHILE HRRR AND NAM PREFER A SOMEWHAT
STRONGER SFC HIGH PRESSURE OVER NORTHERN MINNESOTA...KEEPING MOST
OF THE PRECIP THREAT WELL TO OUR SOUTH.
TONIGHT AND WEDNESDAY...A FLAT SURFACE RIDGE STAYS DRAPED FROM
THE WESTERN GREAT LAKES...AND ACROSS NORTH DAKOTA INTO EASTERN MT.
SOUTHERLY FLOW INCREASES THROUGH THE DAY ON WEDNESDAY PROMISING
SOME REBOUNDING TEMPERATURES...WHILE DEEP MOISTURE STAYS TRAPPED
FOR ANOTHER DAY BY A STATIONARY SURFACE BOUNDARY ACROSS SOUTHERN
SD AND NRN IA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
WEDNESDAY NIGHT AND THURSDAY...INCREASING LOW LEVEL SOUTHERLY
FLOW FROM WEDNESDAY EVENING INTO THURSDAY COULD BRING A BAND OF
MOIST AIR THROUGH EASTERN SD INTO WEST CENTRAL MN...WITH SCT
THUNDERSTORMS BRUSHING AGAINST THE SOUTHEAST EDGE OF THE RED RIVER
BASIN. HAVE STUCK WITH THE NAM AND WITH WPC CONTINUITY IN KEEPING
THE FORECAST DRY FOR THIS PERIOD WHILE THE 00Z GFS HAS BEEN
SOMETHING OF THE WET OUTLIER SOLN.
FRIDAY THROUGH MONDAY...LOW AMPLITUDE LONG WAVE TROUGH OVER THE
GULF OF AK MOVES TO CENTRAL CANADA BY THE END OF THE PERIOD.
ESSENTIALLY ZONAL FLOW REMAINS ACROSS SOUTHERN CANADA AND THE
NORTHERN STATES THROUGH THE PERIOD. ZONAL PATTERN SHIFTS SLOWLY
SOUTH BY THE END OF THE PERIOD. GFS AND ECMWF WERE IN GOOD
AGREEMENT THROUGH 84 HOURS WITH THE UPPER AIR. HOWEVER WITH THE
SURFACE FEATURES THE GFS WAS FAST AT 84 HOURS. THE GFS REMAINS
FASTER THAN THE ECMWF AT DAY 7. WILL BLEND THE ECMWF AND THE GFS.
LITTLE CHANGE TO TEMPS....INCREASES TEMPS A DEGREE OR SO FOR FRI AND
DECREASE A DEGREE OR SO FOR SAT. NO CHANGE TO SUN AND MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM CDT TUE AUG 26 2014
EXPECT AREAS OF MVFR CUMULUS TO LIFT INTO THE VFR RANGE THIS
AFTERNOON OVER NW MN...WITH DIURNAL CUMULUS OVER THE REGION
DIMINISHING LATE TODAY. SOME MID-LEVEL CLOUD COVER WILL SPREAD INTO
E ND...WITH POSSIBLY A SHOWER AT KFAR BY LATE AFTERNOON...BUT
CONFIDENCE IS TOO LOW TO MENTION. OTHERWISE...LIGHT DAYTIME WINDS
WILL BECOME NEARLY CALM OVERNIGHT INTO EARLY WED...BEFORE SHIFTING
SOUTHERLY ON WED. WITH LIGHT WINDS OVERNIGHT...PATCHY FOG
DEVELOPMENT IS POSSIBLE...BUT WILL NOT MENTION AT THIS POINT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GODON
SHORT TERM...GUST
LONG TERM...GUST/HOPPES
AVIATION...MAKOWSKI
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
932 AM CDT TUE AUG 26 2014
.UPDATE...
ISSUED AT 931 AM CDT TUE AUG 26 2014
UPDATED TO LINGER SOME LOW CLOUDS ACROSS NORTHWEST MN THROUGH THE
LATE MORNING. REST OF THE AREA SHOULD SEE ABUNDANT SUNSHINE AND
LIGHT WINDS. SHOULD BE SOME INCREASE IN CLOUDS ACROSS THE SOUTHERN
FA THIS AFTERNOON. MAIN QUESTION IS STILL WHETHER THERE WILL BE
ANY LIGHT SHOWERS THERE. AT THIS POINT SEE NO REASON TO CHANGE SO
WILL CONTINUE TO MONITOR INCOMING NEW MODEL DATA.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
TODAY...SURFACE HIGH PRESSURE CONTINUES TO PRESS OVER THE AREA
PRODUCING LIGHT WEST TO NORTHWEST FLOW...DRYING CONDITIONS AND
UNSEASONABLY COOL TEMPERATURES. RESIDUAL LOW CLOUDS ACROSS
NORTHERN MINNESOTA SHOULD SHIFT EASTWARD THROUGH THE MORNING AS
THE PARENT LOW PRESSURE SYSTEM CONTINUES ITS FAST BREAK ACROSS
NORTHERN ONTARIO AND JAMES BAY. EXPECT GENERALLY FAIR SKIES ACROSS
MOST OF THE AREA THROUGH MIDDAY TODAY...WITH INCREASING MIDDLE TO
LOWER LEVEL MOISTURE MOVING FROM NCNTRL SD INTO SOUTHEAST ND AND
WEST CENTRAL MN THROUGH THE LATER AFTERNOON. AN ISOLATED SHOWER OR
TWO IS POSSIBLE LATE THIS AFTERNOON ACROSS FAR SOUTHERN PORTIONS
OF THE RED RIVER BASIN. FOR NOW...THE RUC SEEMS A BIT OVERLY
AGGRESSIVE WIT THIS FEATURE...WHILE HRRR AND NAM PREFER A SOMEWHAT
STRONGER SFC HIGH PRESSURE OVER NORTHERN MINNESOTA...KEEPING MOST
OF THE PRECIP THREAT WELL TO OUR SOUTH.
TONIGHT AND WEDNESDAY...A FLAT SURFACE RIDGE STAYS DRAPED FROM
THE WESTERN GREAT LAKES...AND ACROSS NORTH DAKOTA INTO EASTERN MT.
SOUTHERLY FLOW INCREASES THROUGH THE DAY ON WEDNESDAY PROMISING
SOME REBOUNDING TEMPERATURES...WHILE DEEP MOISTURE STAYS TRAPPED
FOR ANOTHER DAY BY A STATIONARY SURFACE BOUNDARY ACROSS SOUTHERN
SD AND NRN IA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
WEDNESDAY NIGHT AND THURSDAY...INCREASING LOW LEVEL SOUTHERLY
FLOW FROM WEDNESDAY EVENING INTO THURSDAY COULD BRING A BAND OF
MOIST AIR THROUGH EASTERN SD INTO WEST CENTRAL MN...WITH SCT
THUNDERSTORMS BRUSHING AGAINST THE SOUTHEAST EDGE OF THE RED RIVER
BASIN. HAVE STUCK WITH THE NAM AND WITH WPC CONTINUITY IN KEEPING
THE FORECAST DRY FOR THIS PERIOD WHILE THE 00Z GFS HAS BEEN
SOMETHING OF THE WET OUTLIER SOLN.
FRIDAY THROUGH MONDAY...LOW AMPLITUDE LONG WAVE TROUGH OVER THE
GULF OF AK MOVES TO CENTRAL CANADA BY THE END OF THE PERIOD.
ESSENTIALLY ZONAL FLOW REMAINS ACROSS SOUTHERN CANADA AND THE
NORTHERN STATES THROUGH THE PERIOD. ZONAL PATTERN SHIFTS SLOWLY
SOUTH BY THE END OF THE PERIOD. GFS AND ECMWF WERE IN GOOD
AGREEMENT THROUGH 84 HOURS WITH THE UPPER AIR. HOWEVER WITH THE
SURFACE FEATURES THE GFS WAS FAST AT 84 HOURS. THE GFS REMAINS
FASTER THAN THE ECMWF AT DAY 7. WILL BLEND THE ECMWF AND THE GFS.
LITTLE CHANGE TO TEMPS....INCREASES TEMPS A DEGREE OR SO FOR FRI AND
DECREASE A DEGREE OR SO FOR SAT. NO CHANGE TO SUN AND MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY NIGHT)
ISSUED AT 640 AM CDT TUE AUG 26 2014
GENERALLY FAIR SKIES ACROSS ERN ND WITH AREAS VFR CIGS REMAINING
IN NORTHWEST MN. PATCHY FOG IN THE DEVILS LAKE BASIN SHOULD
DISSIPATE QUICKLY WITH SUNRISE. THROUGH THE MORNING EXPECT CONTINUED
DECREASE IN CLOUD COVER NORTHWEST MN... WITH LINGERING BROKEN CIGS
OVER THE LAKE OF THE WOODS AND RED LAKES REGION THROUGH MID
MORNING. LATE AFTERNOON WILL SEE INCREASING MID LEVEL CLOUDS
ACROSS FAR SOUTHEAST ND...WITH SCT VFR CIGS AND RAIN SHOWERS
POSSIBLE THERE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GODON
SHORT TERM...GUST
LONG TERM...GUST/HOPPES
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
640 AM CDT TUE AUG 26 2014
.UPDATE...
ISSUED AT 640 AM CDT TUE AUG 26 2014
SO SIG CHANGES TO THE PACKAGE THUS FAR. LOW CLOUDS ACROSS
NORTHWEST MN CONTINUE TO SHIFT EASTWARD AND ERODE. PATCHY FOG IN
THE DEVILS LAKE BASIN EXPECTED TO DISSIPATE QUICKLY WITH SUNRISE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
TODAY...SURFACE HIGH PRESSURE CONTINUES TO PRESS OVER THE AREA
PRODUCING LIGHT WEST TO NORTHWEST FLOW...DRYING CONDITIONS AND
UNSEASONABLY COOL TEMPERATURES. RESIDUAL LOW CLOUDS ACROSS
NORTHERN MINNESOTA SHOULD SHIFT EASTWARD THROUGH THE MORNING AS
THE PARENT LOW PRESSURE SYSTEM CONTINUES ITS FAST BREAK ACROSS
NORTHERN ONTARIO AND JAMES BAY. EXPECT GENERALLY FAIR SKIES ACROSS
MOST OF THE AREA THROUGH MIDDAY TODAY...WITH INCREASING MIDDLE TO
LOWER LEVEL MOISTURE MOVING FROM NCNTRL SD INTO SOUTHEAST ND AND
WESTCENTRAL MN THROUGH THE LATER AFTERNOON. AN ISOLATED SHOWER OR
TWO IS POSSIBLE LATE THIS AFTERNOON ACROSS FAR SOUTHERN PORTIONS
OF THE RED RIVER BASIN. FOR NOW...THE RUC SEEMS A BIT OVERLY
AGGRESSIVE WIT THIS FEATURE...WHILE HRRR AND NAM PREFER A SOMEWHAT
STRONGER SFC HIGH PRESSURE OVER NORTHERN MINNESOTA...KEEPING MOST
OF THE PRECIP THREAT WELL TO OUR SOUTH.
TONIGHT AND WEDNESDAY...A FLAT SURFACE RIDGE STAYS DRAPED FROM
THE WESTERN GREAT LAKES...AND ACROSS NORTH DAKOTA INTO EASTERN MT.
SOUTHERLY FLOW INCREASES THROUGH THE DAY ON WEDNESDAY PROMISING
SOME REBOUNDING TEMPERATURES...WHILE DEEP MOISTURE STAYS TRAPPED
FOR ANOTHER DAY BY A STATIONARY SURFACE BOUNDARY ACROSS SOUTHERN
SD AND NRN IA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
WEDNESDAY NIGHT AND THURSDAY...INCREASING LOW LEVEL SOUTHERLY
FLOW FROM WEDNESDAY EVENING INTO THURSDAY COULD BRING A BAND OF
MOIST AIR THROUGH EASTERN SD INTO WESTCENTRAL MN...WITH SCT
THUNDERSTORMS BRUSHING AGAINST THE SOUTHEAST EDGE OF THE RED RIVER
BASIN. HAVE STUCK WITH THE NAM AND WITH WPC CONTINUITY IN KEEPING
THE FORECAST DRY FOR THIS PERIOD WHILE THE 00Z GFS HAS BEEN
SOMETHING OF THE WET OUTLIER SOLN.
FRIDAY THROUGH MONDAY...LOW AMPLITUDE LONG WAVE TROUGH OVER THE
GULF OF AK MOVES TO CENTRAL CANADA BY THE END OF THE PERIOD.
ESSENTIALLY ZONAL FLOW REMAINS ACROSS SOUTHERN CANADA AND THE
NORTHERN STATES THROUGH THE PERIOD. ZONAL PATTERN SHIFTS SLOWLY
SOUTH BY THE END OF THE PERIOD. GFS AND ECMWF WERE IN GOOD
AGREEMENT THROUGH 84 HOURS WITH THE UPPER AIR. HOWEVER WITH THE
SURFACE FEATURES THE GFS WAS FAST AT 84 HOURS. THE GFS REMAINS
FASTER THAN THE ECMWF AT DAY 7. WILL BLEND THE ECMWF AND THE GFS.
LITTLE CHANGE TO TEMPS....INCREASES TEMPS A DEGREE OR SO FOR FRI AND
DECREASE A DEGREE OR SO FOR SAT. NO CHANGE TO SUN AND MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY NIGHT)
ISSUED AT 640 AM CDT TUE AUG 26 2014
GENERALLY FAIR SKIES ACROSS ERN ND WITH AREAS VFR CIGS REMAINING
IN NORTHWEST MN. PATCHY FOG IN THE DEVILS LAKE BASIN SHOULD
DISSATE QUICKLY WITH SUNRISE. THROUGH THE MORNING EXPECT CONTINUED
DECREASE IN CLOUD COVER NORTHWEST MN... WITH LINGERING BROKEN CIGS
OVER THE LAKE OF THE WOODS AND RED LAKES REGION THROUGH MID
MORNING. LATE AFTERNOON WILL SEE INCREASING MID LEVEL CLOUDS
ACROSS FAR SOUTHEAST ND...WITH SCT VFR CIGS AND RAIN SHOWERS
POSSIBLE THERE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GUST
SHORT TERM...GUST
LONG TERM...GUST/HOPPES
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
404 AM CDT TUE AUG 26 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
TODAY...SURFACE HIGH PRESSURE CONTINUES TO PRESS OVER THE AREA
PRODUCING LIGHT WEST TO NORTHWEST FLOW...DRYING CONDITIONS AND
UNSEASONABLY COOL TEMPERATURES. RESIDUAL LOW CLOUDS ACROSS
NORTHERN MINNESOTA SHOULD SHIFT EASTWARD THROUGH THE MORNING AS
THE PARENT LOW PRESSURE SYSTEM CONTINUES ITS FAST BREAK ACROSS
NORTHERN ONTARIO AND JAMES BAY. EXPECT GENERALLY FAIR SKIES ACROSS
MOST OF THE AREA THROUGH MIDDAY TODAY...WITH INCREASING MIDDLE TO
LOWER LEVEL MOISTURE MOVING FROM NCNTRL SD INTO SOUTHEAST ND AND
WESTCENTRAL MN THROUGH THE LATER AFTERNOON. AN ISOLATED SHOWER OR
TWO IS POSSIBLE LATE THIS AFTERNOON ACROSS FAR SOUTHERN PORTIONS
OF THE RED RIVER BASIN. FOR NOW...THE RUC SEEMS A BIT OVERLY
AGGRESSIVE WIT THIS FEATURE...WHILE HRRR AND NAM PREFER A SOMEWHAT
STRONGER SFC HIGH PRESSURE OVER NORTHERN MINNESOTA...KEEPING MOST
OF THE PRECIP THREAT WELL TO OUR SOUTH.
TONIGHT AND WEDNESDAY...A FLAT SURFACE RIDGE STAYS DRAPED FROM
THE WESTERN GREAT LAKES...AND ACROSS NORTH DAKOTA INTO EASTERN MT.
SOUTHERLY FLOW INCREASES THROUGH THE DAY ON WEDNESDAY PROMISING
SOME REBOUNDING TEMPERATURES...WHILE DEEP MOISTURE STAYS TRAPPED
FOR ANOTHER DAY BY A STATIONARY SURFACE BOUNDARY ACROSS SOUTHERN
SD AND NRN IA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE AUG 26 2014
WEDNESDAY NIGHT AND THURSDAY...INCREASING LOW LEVEL SOUTHERLY
FLOW FROM WEDNESDAY EVENING INTO THURSDAY COULD BRING A BAND OF
MOIST AIR THROUGH EASTERN SD INTO WESTCENTRAL MN...WITH SCT
THUNDERSTORMS BRUSHING AGAINST THE SOUTHEAST EDGE OF THE RED RIVER
BASIN. HAVE STUCK WITH THE NAM AND WITH WPC CONTINUITY IN KEEPING
THE FORECAST DRY FOR THIS PERIOD WHILE THE 00Z GFS HAS BEEN
SOMETHING OF THE WET OUTLIER SOLN.
FRIDAY THROUGH MONDAY...LOW AMPLITUDE LONG WAVE TROUGH OVER THE
GULF OF AK MOVES TO CENTRAL CANADA BY THE END OF THE PERIOD.
ESSENTIALLY ZONAL FLOW REMAINS ACROSS SOUTHERN CANADA AND THE
NORTHERN STATES THROUGH THE PERIOD. ZONAL PATTERN SHIFTS SLOWLY
SOUTH BY THE END OF THE PERIOD. GFS AND ECMWF WERE IN GOOD
AGREEMENT THROUGH 84 HOURS WITH THE UPPER AIR. HOWEVER WITH THE
SURFACE FEATURES THE GFS WAS FAST AT 84 HOURS. THE GFS REMAINS
FASTER THAN THE ECMWF AT DAY 7. WILL BLEND THE ECMWF AND THE GFS.
LITTLE CHANGE TO TEMPS....INCREASES TEMPS A DEGREE OR SO FOR FRI AND
DECREASE A DEGREE OR SO FOR SAT. NO CHANGE TO SUN AND MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 345 AM CDT TUE AUG 26 2014
MAINLY VFR CU DECK CONTINUES TO ERODE WITH SKIES HAVING SCATTERED
OUT TO THE WEST OF A GFK-FAR LINE. THROUGH THE EARLY MORNING
EXPECT CONTINUED DECREASE IN CLOUD COVER OVER THE RRV AND ACROSS
NORTHWEST MN... WITH LINGERING BROKEN CIGS OVER THE LAKE OF THE
WOODS AND RED LAKES REGION THROUGH MID MORNING. LATE AFTERNOON
WILL SEE INCREASING MID TO LOWER LEVEL CLOUDS ACROSS FAR SOUTHEAST
ND...WITH SCT VFR CIGS AND RAIN SHOWERS POSSIBLE THERE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...GUST
LONG TERM...GUST/HOPPES
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1158 PM CDT MON AUG 25 2014
.UPDATE...
ISSUED AT 1158 PM CDT MON AUG 25 2014
LATEST SUITE OF SATELLITE IMAGERY SHOWS LOW CLOUDS EXITING THE
JAMES RIVER VALLEY WITH A SMALLER AREA OF LOW CLOUDS IN SOUTHWEST
NORTH DAKOTA. HOWEVER THESE ARE BEING MASKED BY THE INFLUX OF MID
AND HIGH LEVEL MOISTURE ADVECTING IN FROM WYOMING AND WESTERN
SOUTH DAKOTA. THIS IS IN ADVANCE OF SHORTWAVE EJECTING OUT FROM
EASTERN IDAHO WHICH IS FORECAST TO SLIDE ACROSS SOUTHERN NORTH
DAKOTA TUESDAY. VERTICAL MOTION ASSOCIATED WITH THIS SHORTWAVE IN
TANDEM WITH THE RIGHT ENTRANCE REGION OF A 70KT H300 JET STREAK WILL
RESULT IN AN AREA OF LIGHT RAIN SHOWERS TO DEVELOP LATE TONIGHT
INTO THE DAY TUESDAY OVER SOUTHERN NORTH DAKOTA. THE CURRENT
GRIDDED FORECAST HAS THIS COVERED WELL. COOL OVERNIGHT LOW
TEMPERATURES IN THE LOWER 40S REMAINS ON TRACK.
UPDATE ISSUED AT 913 PM CDT MON AUG 25 2014
ONLY CHANGE TO FORECAST WAS TO KEEP CLOUD COVER OVER PORTIONS OF
CENTRAL INTO WESTERN NORTH DAKOTA IN A BIT LONGER THIS EVENING AS
IT HAS BE RELUCTANT TO DISSIPATE OVER SOME LOCATIONS.
OTHERWISE...GOING FORECAST IS IN GOOD SHAPE. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 611 PM CDT MON AUG 25 2014
A FEW SPRINKLES ARE RELUCTANT TO DISSIPATE OVER NORTHWEST NORTH
DAKOTA SO WILL KEEP THEM IN THE FORECAST FOR ANOTHER COUPLE OF
HOURS. OTHERWISE...GOING FORECAST APPEARS IN GOOD SHAPE WITH CLOUD
COVER STARTING TO SLOWLY DISSIPATE. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 323 PM CDT MON AUG 25 2014
THE MAIN FORECAST ISSUES IN THE LONG TERM PERIOD WILL BE
TEMPERATURES TONIGHT AND PRECIPITATION CHANCES SOUTHWEST AND SOUTH
CENTRAL LATE TONIGHT AND TUESDAY. THE PESKY UPPER LOW IS NOW
LIFTING OUT OF THE AREA. ONE LAST TRAILING VORT COMBINED WITH
ANOTHER APPROACHING SHORTWAVE IS KEEPING A FEW SHOWERS OVER
NORTHEAST MONTANA AND NORTHWEST NORTH DAKOTA. THE 18Z HRRR SHOWS
THE SHOWERS HANGING ON THROUGH 00Z. WILL MENTION SOME SCATTED
SPRINKLES NORTHWEST LATE THIS AFTERNOON.
THE APPROACHING SHORTWAVE...IN COMBINATION WITH AN STRENGTHENING
UPPER LEVEL JET WILL PRODUCE INCREASING CLOUDS AND EVENTUALLY A
SWATH OF LIGHT PRECIPITATION...MOVING INTO THE SOUTHWEST LATE
TONIGHT AND SPREADING ACROSS THE SOUTHWEST AND SOUTH CENTRAL ON
TUESDAY. THE INCREASING CLOUDS SHOULD HELP TEMPER THE MERCURY DROP
LATE TONIGHT OVER THE SOUTHWEST. BUT WITH DECREASING CLOUDS...AND
DIMINISHING WINDS...MOST AREAS ARE EXPECTED TO FALL INTO THE
LOWER TO MIDDLE 40S. WOULD NOT BE SURPRISED TO SEE A FEW LOWS
INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 323 PM CDT MON AUG 25 2014
A BROAD POSITIVELY TILTED TROUGH IS FORECAST TO HAVE MOVED EAST OF
THE FORECAST AREA BY TUESDAY NIGHT...WITH DRY CONDITIONS EXPECTED
TUESDAY NIGHT.
A WARMING TREND ALONG WITH DRY CONDITIONS ARE EXPECTED TO CONTINUE
WEDNESDAY THROUGH FRIDAY AS WEAK UPPER LEVEL RIDGING BUILDS OVER
THE NORTHERN PLAINS. NEAR NORMAL HIGHS ARE FORECAST BY FRIDAY.
THE UPPER RIDGE IS PROGGED TO BREAK DOWN SOMEWHAT BY FRIDAY
NIGHT...AND WEAK WAVES IN THE UPPER FLOW ALOFT WILL GENERATE CHANCES
FOR THUNDERSTORMS EACH PERIOD FRIDAY NIGHT THROUGH MONDAY. NEAR
NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH THE WEEKEND AND
INTO MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1158 PM CDT MON AUG 25 2014
EXPECTING MAINLY VFR CIGS/VSBYS NEXT 24HR...HOWEVER AN AREA OF MVFR
CIGS IS POSITIONED IN SOUTHWEST NORTH DAKOTA AND WILL LIKELY INCLUDE
A TEMPO GROUP AT KDIK THROUGH 10Z TUESDAY. ONLY OTHER IMPACT WOULD
BE SOME PATCHY FOG NEAR KMOT...AND HAVE INCLUDED A VCFG FROM 10Z
TUESDAY THROUGH 15Z. SCATTERED RAIN SHOWERS ARE FORECAST ACROSS
SOUTHERN NORTH DAKOTA TUESDAY...WITH KDIK AND KBIS ON THE FAR
NORTHERN FRINGES OF THE PRECIPITATION. INCLUDED A VCSH AT KDIK BUT
NOT AT KBIS.
&&
.HYDROLOGY...
ISSUED AT 323 PM CDT MON AUG 25 2014
HEAVY RAINFALL IN THE PAST COUPLE OF DAYS HAVE CAUSED OVERLAND
FLOODING...AS WELL AS RISES IN CREEKS...RIVERS...AND STREAMS IN
PARTS OF SOUTH CENTRAL NORTH DAKOTA - ESPECIALLY WEST OF THE
MISSOURI RIVER. SIOUX...GRANT...AND WESTERN MORTON COUNTIES SAW
LARGE AREAS OF 2 TO 4 INCHES OF RAIN.
AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR PARTS OF WESTERN MORTON
COUNTY AND PARTS OF NORTHERN GRANT COUNTY. THESE AREAS INCLUDE THE
BIG MUDDY CREEK BETWEEN GLEN ULLIN AND ALMONT...SOUTHWARD TO
HEIL...CARSON...AND LARK. THESE AREAS CONTAIN SMALL CREEKS AND
STREAMS THAT ARE TRIBUTARIES TO THE HEART RIVER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...JV
AVIATION...KS
HYDROLOGY...TWH
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
637 PM CDT WED AUG 27 2014
.AVIATION...
SCTD TSRA AT 630 PM ABOUT 15W LBB MOVG NE WARRANT A TEMPO THUNDER
THRU 02Z AT LBB...BUT OVERALL THESE STORMS SHOULD CONTINUE
DIMINISHING IN COVERAGE IN THE HOURS AHEAD. EARLIER TS AT CDS HAVE
SINCE DISSIPATED AND CONDS THERE LOOK TO BE QUIET THRU THE NIGHT.
ANOTHER ROUND OF TSRA APPEARS LIKELY TO DEVELOP AROUND OR AFTER
18Z THU JUST ABOUT ANYWHERE FROM LBB TO CDS AS AN UPPER TROUGH
MOVES INTO THE REGION. ENTERED GENERIC PROB30S FOR BOTH TERMINALS
AS THE TIMING AND COVERAGE OF TS AT THIS POINT ARE UNCLEAR.
&&
.PREV DISCUSSION... /ISSUED 321 PM CDT WED AUG 27 2014/
SHORT TERM...
WV SHOWS THE UPPER LEVEL LOW OF INTEREST CURRENTLY POSITIONED OVER
UT WITH EASTERN NM/WESTERN TX SITTING UNDER A PLUME OF MONSOONAL
MOISTURE THAT IS BEING SUCKED INTO THE LOW. A FEW SHORTWAVES MAKING
THEIR WAY ACROSS NM ARE NOTICED AHEAD OF THE MAIN LOW. THESE
SHORTWAVES WILL TRIGGER OUR FIRST ROUND OF PRECIP LATER TONIGHT.
POPS THROUGH TOMORROW MORNING REMAIN MOSTLY UNCHANGED WITH THE
EXCEPTION OF CHANCE MENTION HAVING BEEN EXPANDED SLIGHTLY EASTWARD.
WHILE THE MAIN SOURCE OF LIFT WILL BE TO OUR WEST...UPPER LEVEL FLOW
OVERHEAD WILL REMAIN SLIGHTLY DIFFLUENT. AS HAS BEEN SEEN THE PAST
SEVERAL DAYS...IT DOES NOT TAKE MUCH LIFT TO FIRE SHALLOW CONVECTION.
ONE NOTE OF INTEREST IS THE 15Z HRRR DEVELOPING A LINE SHALLOW
CONVECTION ALONG THE EDGE OF THE CAPROCK THIS AFTERNOON WHERE WEAK
SURFACE CONVERGENCE IS OBSERVED. CHANCES WILL INCREASE AFTER 12Z
TOMORROW MORNING AS AN UPPER LEVEL JET BEGINS TO FORM JUST TO OUR
NORTHEAST PUTTING A MAJORITY OF OUR EASTERN ZONES IN THE ENTRANCE
REGION OF THE JET HELPING PROMOTE DIVERGENCE. DUE TO INCREASING
DIVERGENCE THROUGH THE AFTERNOON COUPLED WITH PWATS APPROACHING 2
INCHES SUB-LIKELY POPS HAVE BEEN INSERTED ACROSS MUCH OF THE ROLLING
PLAINS. ONE ISSUE THAT WILL NEED TO BE WATCHED IS THE POSSIBILITY OF
LOCALIZED FLOODING DUE TO TRAINING THUNDERSTORMS.
THE SURFACE FRONT WILL APPROACH OUR NORTHWESTERN ZONES EARLY
TOMORROW MORNING BUT SHOULD NOT MAKE IT FAR INTO THE FA WITH THE
FARTHEST EXTENT BEING ALONG A LINE FROM DIMMITT TO BROWNFIELD. CAA
WILL BE RATHER WEAK WITH THIS FRONT WITH TEMPS MODERATING ONLY A FEW
DEGREES FROM WHAT WE WILL SEE TODAY. HIGHS ACROSS THE WESTERN SOUTH
PLAINS AND SOUTHWESTERN TX PANHANDLE SHOULD BE IN THE UPPER 80S/LOW
90S. WITH THE FRONT BEING WEAK COMPRESSIONAL HEATING SHOULD NOT BE
TOO HUGE OF AN ISSUE WHICH WILL PREVENT HIGHS FROM MELTING THE
PAVEMENT OFF OF ROADS.
LONG TERM...
THE UA TROUGH NOTED ACROSS NERN UTAH LATE THIS AFTN...IS PROGGED
TO CONTINUE TO PROGRESS EWRD TO ACROSS THE CNTRL/SRN PLAINS BY
TOMORROW NIGHT. A PERSISTENT UPSLOPE SFC REGIME WILL ALLOW FOR
PWATS TO INCREASE ON THE ORDER OF 1.25-1.70 INCHES ACROSS THE FA
WHICH COUPLED WITH INCREASED LARGE SCALE ASCENT...WILL AID IN
CONTINUED CHANCES FOR SHOWER AND THUNDERSTORM DEVELOPMENT TOMORROW
NIGHT. FURTHERMORE...A COLD FRONT ASSOCIATED WITH THE
AFOREMENTIONED UA TROUGH MAY IMPINGE ON THE FAR SRN TX
PANHANDLE...NRN SOUTH PLAINS AND NRN ROLLING PLAINS DURING THE DAY
FRIDAY AS HINTED AT BY MODEL SOLUTIONS...WHICH COULD AID IN
CONTINUAL PRECIP CHANCES. HOWEVER...UL SUPPORT WILL COMMENCE TO
DECLINE AS THE UA TROUGH EXITS EAST OF THE REGION BY FRIDAY AFTN.
NONETHELESS...THE PRESENCE OF THE FRONT IS ENOUGH TO MAINTAIN
MENTIONABLE POPS FRIDAY...WITH HIGHEST POPS ACROSS THE ROLLING
PLAINS NEAREST TO THE DEPARTING LARGE SCALE ASCENT. THE POTENTIAL
FOR STORMS TO BECOME SEVERE APPEARS LOW AS A BIT OF A VEERING WIND
PROFILE LACKS SIGNIFICANT WIND SPEEDS ALOFT...HOWEVER LOCALIZED
FLOODING CAN NOT BE RULED DUE TO THE ANTICIPATED ABOVE NORMAL
PWATS.
BY SATURDAY...RATHER LOW AMPLITUDE RIDGING WILL PROGRESS EWRD ACROSS
THE CNTRL CONUS...THOUGH IT IS INTERESTING TO NOTE THAT MODEL
SOLUTIONS DISPLAY LIGHT QPF SIGNALS ACROSS THE CWA. WITH THE
PREVIOUSLY MENTIONED COLD FRONT WASHED OUT/RETREATED NORTH...THE
LIGHT PRECIP APPEARS TO BE CAUSED BY AN EMBEDDED IMPULSE IN THE
FLOW ALOFT. WILL GO AHEAD AND INSERT 10-14 POPS FOR NOW. A NEARBY
SFC TROUGH WILL PROMOTE BREEZY SRLY SFC WINDS FOR THE
WEEKEND...WHILST A BROAD UA LOW AFFECTING SRN CANADA/NORTHERN
ROCKIES WILL CAUSE FLOW ALOFT TO BECOME ZONAL ACROSS THE SRN
PLAINS. AS THE SAID UA SYSTEM TRANSLATES EAST ACROSS THE NRN
PLAINS...IT WILL PUSH A BACKDOOR COLD FRONT TO ACROSS THE FAR SERN
TX PANHANDLE MONDAY...WHICH COULD SERVE AS A PRECIP FOCUS. WILL
HOLD ON TO SILENT POPS BEYOND FRIDAY ATTM...THOUGH WILL NEED TO
KEEP AN EYE ON LATER MODEL RUNS AND SEE IF THIS TRENDS HOLDS FOR
NEXT WEEK.
WITH THE ANTICIPATED RAINFALL AND INCREASED CLOUDINESS EXPECTED
EARLY IN THE EXTENDED PERIOD...TEMPS WILL COOL INTO THE UPPER
80S-LOWER 90S ON FRIDAY. TEMPS WILL QUICKLY REBOUND BACK INTO THE
90S BY THE WEEKEND...AND POSSIBLY NEAR LOWER TRIPLE DIGITS OFF
THE CAPROCK BY EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 62 88 59 86 60 / 40 30 30 20 20
TULIA 66 88 62 86 63 / 40 40 40 30 20
PLAINVIEW 66 89 63 87 64 / 30 40 40 20 20
LEVELLAND 66 91 64 88 64 / 30 40 40 20 20
LUBBOCK 69 91 67 90 67 / 30 40 40 30 20
DENVER CITY 66 93 65 90 65 / 30 40 40 20 20
BROWNFIELD 67 93 65 90 65 / 30 40 40 20 20
CHILDRESS 73 92 69 90 70 / 30 50 50 30 30
SPUR 68 94 66 91 67 / 20 50 50 30 30
ASPERMONT 72 97 70 94 70 / 20 50 50 30 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
946 AM CDT TUE AUG 26 2014
.DISCUSSION...
STORMS HAVE DISSIPATED OVER LAND BUT SHOULD RETURN THIS AFTERNOON
AS TEMPERATURES REACH 88-91 DEGREES. A LITTLE BIT OF THE DRIER AIR
TO THE NORTHEAST CAN BE SEEN IN THE AM AMDAR SOUNDINGS BUT CLOSER
TO THE COAST MORE MOISTURE IS PRESENT AND SHOULD SUPPORT A CHANCE
OF SHOWERS AND THUNDERSTORMS STORM MOTIONS WILL BE SLOW AND MAINLY
FROM NORTHEAST TO SOUTHWEST THOUGH CLOSER TO THE COAST SLOWER YET
AND MAY EVEN BE STATIONARY ALONG THE SEABREEZE AS IT TRIES TO PUSH
INLAND. MADE SOME CHANGES TO THE SKY COVER AS MUCH OF THE AREA HAS
GONE MS/PC BUT AGAIN THIS WILL CHANGE BACK TO PC/MC WITH CONTINUED
HEATING. AREAS IN THE WEST WILL BE THE WARMEST TODAY AND COULD SEE
HIGHS OF 95-98 WITH THE CORRESPONDING HIGHER HEAT INDEX READINGS
OF 100-104.
NHC HAS GIVEN THE DISTURBANCE IN THE GULF A 10 PERCENT CHANCE OF
DEVELOPMENT.
45
&&
.PREV DISCUSSION... /ISSUED 716 AM CDT TUE AUG 26 2014/
DISCUSSION...
UPDATED AVIATION DISCUSSION.
AVIATION...
VFR CONDITIONS CURRENTLY PREVAIL AT THE TAF SITES. A FEW SHOWERS
HAD POPPED UP WEST OF CLL AND ALONG AN AXIS SOUTH BUT THESE HAVE
DISSIPATED OVER THE PAST HOUR OR SO. ANOTHER CLUSTER OF SHOWERS
AND STORMS IS LOCATED MANLY OFFSHORE. TODAY EXPECT SHOWERS AND A
FEW THUNDERSTORMS TO PERCOLATE UP WITH DAYTIME HEATING AND
ENHANCED BY UPPER DISTURBANCE. GREATEST COVERAGE LOOKS TO BE AT
THE IMMEDIATE COAST SO HAVE GONE WITH TEMPO THUNDER AT GLS AND
LBX. FOR NEXT TIER NORTH...SGR AND HOU...HAVE GONE TEMPO SHRA AS
CAPE AND COVERAGE WILL BE MORE LIMITED BUT SHOWERS AND POSSIBLY AN
ISOLATED TSTRM WILL BE AROUND. FARTHER NORTH YET...AT CXO...UTS
AND CLL...CANT RULE OUT AN ISOLATED SHOWER...BUT MESO MODELS
SUGGEST LIMITED COVERAGE. FOR THOSE SITES THINK VCSH IS
APPROPRIATE. 46
PREV DISCUSSION... /ISSUED 444 AM CDT TUE AUG 26 2014/
DISCUSSION...
MORNING SFC ANALYSIS SHOWS FAIRLY WEAK PRESSURE GRADIENT ACROSS
MUCH OF TX WITH MAINLY E/SE WINDS ALONG THE UPPER TX COAST. WATER
VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH MOVING ACROSS THE N GULF
TOWARDS SE TX. THE 00Z SOUNDING FROM LCH SHOWED 2.4 INCHES OF
PRECIP WATER WHICH IS QUITE HIGH FOR THIS TIME OF YEAR BEING 2 STD
DEV FROM NORMAL. GOES PRECIP WATER SOUNDER DATA SHOWS AT LEAST
THIS MUCH MOISTURE OVER A LARGE PORTION OF THE AREA. THIS BROAD
AREA OF DEEP MOISTURE EXTENDS FROM INLAND AREAS TO WELL OFF THE
COAST. SHORT RANGE MODELS ADVECT MUCH MORE MOIST AIRMASS INTO SE
TX WHICH MAKES SENSE BASED OFF 00Z LCH WIND PROFILE. THE NAM SEEMS
TO BE A BIT MORE AGGRESSIVE WITH BRINGING THE MOISTURE INTO THE
AREA WHERE GFS IS SLOWER. GFS IS ALSO FASTER IN BRINGING SOME
DRIER AIR INTO THE AREA FROM THE EAST. THIS MAY IMPACT
THUNDERSTORM CHANCES MID WEEK ESPECIALLY OVER NORTHERN PORTIONS OF
SE TX. FOR NOW RADAR SHOWS ACTIVITY ORGANIZING IN THE GULF AND
THIS WILL LIKELY BE THE BEGINNING OF THUNDERSTORM ACTIVITY ALONG
THE COAST. THINK 40/50 POPS LOOK ON TRACK FOR MUCH OF THE AREA FOR
THE REST OF THE WEEK. ON A CURIOUS NOTE...MESO MODELS SUCH AS WRF
ARW AND HRRR ARE NOT VERY ROBUST WITH CONVECTION FORMING UNTIL
MUCH LATER IN THE AFTERNOON. THIS BRINGS IN SOME DOUBT AS TO HOW
CONVECTION WILL EVOLVE TODAY.
UPPER LEVEL PATTERN WILL BE QUITE CONDUCIVE FOR CONVECTION. WATER
VAPOR IMAGERY SHOWS SHORTWAVE MOVING INTO SE TX FROM THE N GULF
TODAY AND FORECAST MODELS CONTINUE TO STALL THIS FEATURE ALONG THE
COAST OR JUST INLAND OF MIDDLE TX COAST ON WEDNESDAY. THIS MEANS
AN OVERALL WEAKNESS IN THE RIDGE WILL EXIST AND ONLY STRENGTHENED
BY BROAD TROUGH NOW OVER THE GREAT BASIN MOVING INTO THE PLAINS
FOR FRIDAY INTO SATURDAY. THE CUTOFF SHORTWAVE OR TUTT LOW WILL
THEN LIFT NORTH AS THE UPPER TROUGH STARTS TO MOVE THROUGH THE
PLAINS LATE FRI INTO SAT. AFTER THE TROUGH LIFTS OVERALL UPPER
LEVEL RIDGING OCCURS BUT THE RIDGE SEEMS TO BE STRETCHED OUT ALL
ALONG THE SOUTHERN TIER OF STATES.
THE OTHER MAJOR INGREDIENT FOR THUNDERSTORM CHANCES IS MOISTURE.
GOES SOUNDER PRECIP WATER PRODUCT SHOWS DEEP MOISTURE AXIS OR
ATMOSPHERIC MOISTURE RIVER COMING FROM THE CARIBBEAN INTO THE N
GULF. THIS PLUME OF MOISTURE WILL VARY IN ITS OVERALL MOISTURE
CONTENT FROM DAY TO DAY BUT IT WILL NOT TAKE MUCH TIME FOR
CONVECTION TO DEVELOP. MODEL SOUNDINGS SUPPORT CONVECTIVE TEMPS IN
THE UPPER 80S TO LOW 90S WITH PRECIP WATER VALUES AROUND 2.2 TO
2.4 INCHES. THIS MOISTURE PLUME REMAINING IN PLACE FOR THE NEXT
DAY OR TWO SHOULD SUPPORT CONTINUED THUNDERSTORM ACTIVITY ACROSS
THE AREA. WITH BREAKS IN CLOUD COVER THESE CONVECTIVE TEMPS LOOK
TO BE ACHIEVABLE EVEN IN THE LATE MORNING HOURS. IT LOOKS LIKE
TODAY INTO WEDNESDAY WILL CARRY THE HIGHEST CHANCES BUT EVEN 30/40
POPS LOOK REASONABLE FOR THE END OF THE WEEK.
CONVECTION AND CLOUD COVER SHOULD KNOCK TEMPS DOWN A COUPLE OF
DEGREES FROM THE LAST FEW DAYS. HIGH TEMPS WILL REACH LOW 90S
ALONG THE COAST AND POSSIBLY INLAND. MIN TEMPS MAY BE ABOVE
NORMAL WITH HIGHER MOISTURE ALONG THE COAST. LOW TEMPS WILL MAINLY
BE DRIVEN BY ANY OUTFLOW BOUNDARIES THAT MOVE THROUGH THE AREA.
MAIN IMPACTS FROM THIS CHANGE IN THE WEATHER PATTERN WILL BE
POSSIBILITY OF HEAVY RAINFALL ON ANY OF THE NEXT FEW DAYS. HIGHEST
RAINFALL TOTALS WILL LIKELY BE ALONG THE COAST AND OFFSHORE.
THAT`S NOT TO SAY A FEW STRONG STORMS COULD NOT FORM INLAND WHICH
COULD PRODUCE HEAVY RAINFALL. HOURLY RAIN RATES OF 1-2 INCHES AN
HOUR WOULD NOT BE OUT OF THE QUESTION SO ISO 1-3 INCH AMOUNTS
WOULD BE POSSIBLE. LOOKING AT GRIDDED FFG AND NASA SPORT LIS
DATA...IF ANYTHING MOST FLOOD PRONE AREAS WILL BE EAST OF
INTERSTATE 45 INTO E TX. AT THIS TIME ANY FLOODING PROBLEMS WILL
BE VERY LOCALIZED. OF COURSE URBAN AREAS WITH POOR DRAINAGE WILL
ALWAYS BE AN ISSUE ONCE RAIN RATES APPROACH 2 INCHES AN HOUR. THE
HARDEST PART OF THE FORECAST IS TRYING THE NARROW DOWN ANY ONE DAY
THAT WILL HAVE A HIGHER POTENTIAL FOR HEAVY RAINFALL. AT THIS TIME
THE NEXT 4 DAYS HAVE THAT POTENTIAL.
39
MARINE...
AN UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND THUNDERSTORMS
TO THE WATERS TODAY AND WEDNESDAY. FAIRLY LIGHT EAST TO SOUTHEAST
FLOW WILL BECOME MORE MODERATE...MAINLY IN THE 10 TO 15 KNOT
RANGE...LATER THIS AFTERNOON...AND CONTINUING THROUGH LATE IN THE
WEEK. THERE WILL BE AN INCREASE IN SEAS CORRESPONDING...INTO THE 2
TO 4 FEET RANGE FOR COASTAL WATERS.
46
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 96 76 96 75 93 / 20 20 20 20 30
HOUSTON (IAH) 92 77 93 76 92 / 50 20 40 20 50
GALVESTON (GLS) 90 80 88 80 89 / 50 40 50 50 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...45
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
716 AM CDT TUE AUG 26 2014
.DISCUSSION...
UPDATED AVIATION DISCUSSION.
&&
.AVIATION...
VFR CONDITIONS CURRENTLY PREVAIL AT THE TAF SITES. A FEW SHOWERS
HAD POPPPED UP WEST OF CLL AND ALONG AN AXIS SOUTH BUT THESE HAVE
DISSIPATED OVER THE PAST HOUR OR SO. ANOTHER CLUSTER OF SHOWERS
AND STORMS IS LOCATED MANLY OFFSHORE. TODAY EXPECT SHOWERS AND A
FEW THUNDERSTORMS TO PERCOLATE UP WITH DAYTIME HEATING AND
ENHANCED BY UPPER DISTURBANCE. GREATEST COVERAGE LOOKS TO BE AT
THE IMMEDIATE COAST SO HAVE GONE WITH TEMPO THUNDER AT GLS AND
LBX. FOR NEXT TIER NORTH...SGR AND HOU...HAVE GONE TEMPO SHRA AS
CAPE AND COVERAGE WILL BE MORE LIMITED BUT SHOWERS AND POSSIBLY AN
ISOLATED TSTRM WILL BE AROUND. FARTHER NORTH YET...AT CXO...UTS
AND CLL...CANT RULE OUT AN ISOLATED SHOWER...BUT MESO MODELS
SUGGEST LIMITED COVERAGE. FOR THOSE SITES THINK VCSH IS
APPROPRIATE. 46
&&
.PREV DISCUSSION... /ISSUED 444 AM CDT TUE AUG 26 2014/
DISCUSSION...
MORNING SFC ANALYSIS SHOWS FAIRLY WEAK PRESSURE GRADIENT ACROSS
MUCH OF TX WITH MAINLY E/SE WINDS ALONG THE UPPER TX COAST. WATER
VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH MOVING ACROSS THE N GULF
TOWARDS SE TX. THE 00Z SOUNDING FROM LCH SHOWED 2.4 INCHES OF
PRECIP WATER WHICH IS QUITE HIGH FOR THIS TIME OF YEAR BEING 2 STD
DEV FROM NORMAL. GOES PRECIP WATER SOUNDER DATA SHOWS AT LEAST
THIS MUCH MOISTURE OVER A LARGE PORTION OF THE AREA. THIS BROAD
AREA OF DEEP MOISTURE EXTENDS FROM INLAND AREAS TO WELL OFF THE
COAST. SHORT RANGE MODELS ADVECT MUCH MORE MOIST AIRMASS INTO SE
TX WHICH MAKES SENSE BASED OFF 00Z LCH WIND PROFILE. THE NAM SEEMS
TO BE A BIT MORE AGGRESSIVE WITH BRINGING THE MOISTURE INTO THE
AREA WHERE GFS IS SLOWER. GFS IS ALSO FASTER IN BRINGING SOME
DRIER AIR INTO THE AREA FROM THE EAST. THIS MAY IMPACT
THUNDERSTORM CHANCES MID WEEK ESPECIALLY OVER NORTHERN PORTIONS OF
SE TX. FOR NOW RADAR SHOWS ACTIVITY ORGANIZING IN THE GULF AND
THIS WILL LIKELY BE THE BEGINNING OF THUNDERSTORM ACTIVITY ALONG
THE COAST. THINK 40/50 POPS LOOK ON TRACK FOR MUCH OF THE AREA FOR
THE REST OF THE WEEK. ON A CURIOUS NOTE...MESO MODELS SUCH AS WRF
ARW AND HRRR ARE NOT VERY ROBUST WITH CONVECTION FORMING UNTIL
MUCH LATER IN THE AFTERNOON. THIS BRINGS IN SOME DOUBT AS TO HOW
CONVECTION WILL EVOLVE TODAY.
UPPER LEVEL PATTERN WILL BE QUITE CONDUCIVE FOR CONVECTION. WATER
VAPOR IMAGERY SHOWS SHORTWAVE MOVING INTO SE TX FROM THE N GULF
TODAY AND FORECAST MODELS CONTINUE TO STALL THIS FEATURE ALONG THE
COAST OR JUST INLAND OF MIDDLE TX COAST ON WEDNESDAY. THIS MEANS
AN OVERALL WEAKNESS IN THE RIDGE WILL EXIST AND ONLY STRENGTHENED
BY BROAD TROUGH NOW OVER THE GREAT BASIN MOVING INTO THE PLAINS
FOR FRIDAY INTO SATURDAY. THE CUTOFF SHORTWAVE OR TUTT LOW WILL
THEN LIFT NORTH AS THE UPPER TROUGH STARTS TO MOVE THROUGH THE
PLAINS LATE FRI INTO SAT. AFTER THE TROUGH LIFTS OVERALL UPPER
LEVEL RIDGING OCCURS BUT THE RIDGE SEEMS TO BE STRETCHED OUT ALL
ALONG THE SOUTHERN TIER OF STATES.
THE OTHER MAJOR INGREDIENT FOR THUNDERSTORM CHANCES IS MOISTURE.
GOES SOUNDER PRECIP WATER PRODUCT SHOWS DEEP MOISTURE AXIS OR
ATMOSPHERIC MOISTURE RIVER COMING FROM THE CARIBBEAN INTO THE N
GULF. THIS PLUME OF MOISTURE WILL VARY IN ITS OVERALL MOISTURE
CONTENT FROM DAY TO DAY BUT IT WILL NOT TAKE MUCH TIME FOR
CONVECTION TO DEVELOP. MODEL SOUNDINGS SUPPORT CONVECTIVE TEMPS IN
THE UPPER 80S TO LOW 90S WITH PRECIP WATER VALUES AROUND 2.2 TO
2.4 INCHES. THIS MOISTURE PLUME REMAINING IN PLACE FOR THE NEXT
DAY OR TWO SHOULD SUPPORT CONTINUED THUNDERSTORM ACTIVITY ACROSS
THE AREA. WITH BREAKS IN CLOUD COVER THESE CONVECTIVE TEMPS LOOK
TO BE ACHIEVABLE EVEN IN THE LATE MORNING HOURS. IT LOOKS LIKE
TODAY INTO WEDNESDAY WILL CARRY THE HIGHEST CHANCES BUT EVEN 30/40
POPS LOOK REASONABLE FOR THE END OF THE WEEK.
CONVECTION AND CLOUD COVER SHOULD KNOCK TEMPS DOWN A COUPLE OF
DEGREES FROM THE LAST FEW DAYS. HIGH TEMPS WILL REACH LOW 90S
ALONG THE COAST AND POSSIBLY INLAND. MIN TEMPS MAY BE ABOVE
NORMAL WITH HIGHER MOISTURE ALONG THE COAST. LOW TEMPS WILL MAINLY
BE DRIVEN BY ANY OUTFLOW BOUNDARIES THAT MOVE THROUGH THE AREA.
MAIN IMPACTS FROM THIS CHANGE IN THE WEATHER PATTERN WILL BE
POSSIBILITY OF HEAVY RAINFALL ON ANY OF THE NEXT FEW DAYS. HIGHEST
RAINFALL TOTALS WILL LIKELY BE ALONG THE COAST AND OFFSHORE.
THAT`S NOT TO SAY A FEW STRONG STORMS COULD NOT FORM INLAND WHICH
COULD PRODUCE HEAVY RAINFALL. HOURLY RAIN RATES OF 1-2 INCHES AN
HOUR WOULD NOT BE OUT OF THE QUESTION SO ISO 1-3 INCH AMOUNTS
WOULD BE POSSIBLE. LOOKING AT GRIDDED FFG AND NASA SPORT LIS
DATA...IF ANYTHING MOST FLOOD PRONE AREAS WILL BE EAST OF
INTERSTATE 45 INTO E TX. AT THIS TIME ANY FLOODING PROBLEMS WILL
BE VERY LOCALIZED. OF COURSE URBAN AREAS WITH POOR DRAINAGE WILL
ALWAYS BE AN ISSUE ONCE RAIN RATES APPROACH 2 INCHES AN HOUR. THE
HARDEST PART OF THE FORECAST IS TRYING THE NARROW DOWN ANY ONE DAY
THAT WILL HAVE A HIGHER POTENTIAL FOR HEAVY RAINFALL. AT THIS TIME
THE NEXT 4 DAYS HAVE THAT POTENTIAL.
39
MARINE...
AN UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND THUNDERSTORMS
TO THE WATERS TODAY AND WEDNESDAY. FAIRLY LIGHT EAST TO SOUTHEAST
FLOW WILL BECOME MORE MODERATE...MAINLY IN THE 10 TO 15 KNOT
RANGE...LATER THIS AFTERNOON...AND CONTINUING THROUGH LATE IN THE
WEEK. THERE WILL BE AN INCREASE IN SEAS CORRESPONDING...INTO THE 2
TO 4 FEET RANGE FOR COASTAL WATERS.
46
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 96 76 96 75 93 / 20 20 20 20 30
HOUSTON (IAH) 92 77 93 76 92 / 50 20 40 20 50
GALVESTON (GLS) 90 80 88 80 89 / 50 40 50 50 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS HOUSTON/GALVESTON TX
444 AM CDT TUE AUG 26 2014
.DISCUSSION...
MORNING SFC ANALYSIS SHOWS FAIRLY WEAK PRESSURE GRADIENT ACROSS
MUCH OF TX WITH MAINLY E/SE WINDS ALONG THE UPPER TX COAST. WATER
VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH MOVING ACROSS THE N GULF
TOWARDS SE TX. THE 00Z SOUNDING FROM LCH SHOWED 2.4 INCHES OF
PRECIP WATER WHICH IS QUITE HIGH FOR THIS TIME OF YEAR BEING 2 STD
DEV FROM NORMAL. GOES PRECIP WATER SOUNDER DATA SHOWS AT LEAST
THIS MUCH MOISTURE OVER A LARGE PORTION OF THE AREA. THIS BROAD
AREA OF DEEP MOISTURE EXTENDS FROM INLAND AREAS TO WELL OFF THE
COAST. SHORT RANGE MODELS ADVECT MUCH MORE MOIST AIRMASS INTO SE
TX WHICH MAKES SENSE BASED OFF 00Z LCH WIND PROFILE. THE NAM SEEMS
TO BE A BIT MORE AGGRESSIVE WITH BRINGING THE MOISTURE INTO THE
AREA WHERE GFS IS SLOWER. GFS IS ALSO FASTER IN BRINGING SOME
DRIER AIR INTO THE AREA FROM THE EAST. THIS MAY IMPACT
THUNDERSTORM CHANCES MID WEEK ESPECIALLY OVER NORTHERN PORTIONS OF
SE TX. FOR NOW RADAR SHOWS ACTIVITY ORGANIZING IN THE GULF AND
THIS WILL LIKELY BE THE BEGINNING OF THUNDERSTORM ACTIVITY ALONG
THE COAST. THINK 40/50 POPS LOOK ON TRACK FOR MUCH OF THE AREA FOR
THE REST OF THE WEEK. ON A CURIOUS NOTE...MESO MODELS SUCH AS WRF
ARW AND HRRR ARE NOT VERY ROBUST WITH CONVECTION FORMING UNTIL
MUCH LATER IN THE AFTERNOON. THIS BRINGS IN SOME DOUBT AS TO HOW
CONVECTION WILL EVOLVE TODAY.
UPPER LEVEL PATTERN WILL BE QUITE CONDUCIVE FOR CONVECTION. WATER
VAPOR IMAGERY SHOWS SHORTWAVE MOVING INTO SE TX FROM THE N GULF
TODAY AND FORECAST MODELS CONTINUE TO STALL THIS FEATURE ALONG THE
COAST OR JUST INLAND OF MIDDLE TX COAST ON WEDNESDAY. THIS MEANS
AN OVERALL WEAKNESS IN THE RIDGE WILL EXIST AND ONLY STRENGTHENED
BY BROAD TROUGH NOW OVER THE GREAT BASIN MOVING INTO THE PLAINS
FOR FRIDAY INTO SATURDAY. THE CUTOFF SHORTWAVE OR TUTT LOW WILL
THEN LIFT NORTH AS THE UPPER TROUGH STARTS TO MOVE THROUGH THE
PLAINS LATE FRI INTO SAT. AFTER THE TROUGH LIFTS OVERALL UPPER
LEVEL RIDGING OCCURS BUT THE RIDGE SEEMS TO BE STRETCHED OUT ALL
ALONG THE SOUTHERN TIER OF STATES.
THE OTHER MAJOR INGREDIENT FOR THUNDERSTORM CHANCES IS MOISTURE.
GOES SOUNDER PRECIP WATER PRODUCT SHOWS DEEP MOISTURE AXIS OR
ATMOSPHERIC MOISTURE RIVER COMING FROM THE CARIBBEAN INTO THE N
GULF. THIS PLUME OF MOISTURE WILL VARY IN ITS OVERALL MOISTURE
CONTENT FROM DAY TO DAY BUT IT WILL NOT TAKE MUCH TIME FOR
CONVECTION TO DEVELOP. MODEL SOUNDINGS SUPPORT CONVECTIVE TEMPS IN
THE UPPER 80S TO LOW 90S WITH PRECIP WATER VALUES AROUND 2.2 TO
2.4 INCHES. THIS MOISTURE PLUME REMAINING IN PLACE FOR THE NEXT
DAY OR TWO SHOULD SUPPORT CONTINUED THUNDERSTORM ACTIVITY ACROSS
THE AREA. WITH BREAKS IN CLOUD COVER THESE CONVECTIVE TEMPS LOOK
TO BE ACHIEVABLE EVEN IN THE LATE MORNING HOURS. IT LOOKS LIKE
TODAY INTO WEDNESDAY WILL CARRY THE HIGHEST CHANCES BUT EVEN 30/40
POPS LOOK REASONABLE FOR THE END OF THE WEEK.
CONVECTION AND CLOUD COVER SHOULD KNOCK TEMPS DOWN A COUPLE OF
DEGREES FROM THE LAST FEW DAYS. HIGH TEMPS WILL REACH LOW 90S
ALONG THE COAST AND POSSIBLY INLAND. MIN TEMPS MAY BE ABOVE
NORMAL WITH HIGHER MOISTURE ALONG THE COAST. LOW TEMPS WILL MAINLY
BE DRIVEN BY ANY OUTFLOW BOUNDARIES THAT MOVE THROUGH THE AREA.
MAIN IMPACTS FROM THIS CHANGE IN THE WEATHER PATTERN WILL BE
POSSIBILITY OF HEAVY RAINFALL ON ANY OF THE NEXT FEW DAYS. HIGHEST
RAINFALL TOTALS WILL LIKELY BE ALONG THE COAST AND OFFSHORE.
THAT`S NOT TO SAY A FEW STRONG STORMS COULD NOT FORM INLAND WHICH
COULD PRODUCE HEAVY RAINFALL. HOURLY RAIN RATES OF 1-2 INCHES AN
HOUR WOULD NOT BE OUT OF THE QUESTION SO ISO 1-3 INCH AMOUNTS
WOULD BE POSSIBLE. LOOKING AT GRIDDED FFG AND NASA SPORT LIS
DATA...IF ANYTHING MOST FLOOD PRONE AREAS WILL BE EAST OF
INTERSTATE 45 INTO E TX. AT THIS TIME ANY FLOODING PROBLEMS WILL
BE VERY LOCALIZED. OF COURSE URBAN AREAS WITH POOR DRAINAGE WILL
ALWAYS BE AN ISSUE ONCE RAIN RATES APPROACH 2 INCHES AN HOUR. THE
HARDEST PART OF THE FORECAST IS TRYING THE NARROW DOWN ANY ONE DAY
THAT WILL HAVE A HIGHER POTENTIAL FOR HEAVY RAINFALL. AT THIS TIME
THE NEXT 4 DAYS HAVE THAT POTENTIAL.
39
&&
.MARINE...
AN UPPER LEVEL DISTURBANCE WILL BRING SHOWERS AND THUNDERSTORMS
TO THE WATERS TODAY AND WEDNESDAY. FAIRLY LIGHT EAST TO SOUTHEAST
FLOW WILL BECOME MORE MODERATE...MAINLY IN THE 10 TO 15 KNOT
RANGE...LATER THIS AFTERNOON...AND CONTINUING THROUGH LATE IN THE
WEEK. THERE WILL BE AN INCREASE IN SEAS CORRESPONDING...INTO THE 2
TO 4 FEET RANGE FOR COASTAL WATERS.
46
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 96 76 96 75 93 / 20 20 20 20 30
HOUSTON (IAH) 92 77 93 76 92 / 50 20 40 20 50
GALVESTON (GLS) 90 80 88 80 89 / 50 40 50 50 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AVIATION/MARINE...46
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1124 PM CDT MON AUG 25 2014
.AVIATION...
/6Z TAFS/
VFR CONDITIONS EXPECTED THROUGH THE PERIOD ALTHOUGH SOME HIGH
CLOUD IS SPREADING INTO THE AREA FROM CONVECTION TO THE EAST. THIS
SHOULD THIN OUT OVERNIGHT. GENERALLY LIGHT EAST-SOUTHEAST WINDS
WILL PREVAIL THROUGH TUESDAY. THERE IS SOME INCREASING MOISTURE
ACROSS EAST TEXAS WHICH WILL MOVE INTO NORTH TEXAS TOMORROW AND
WILL LIKELY SET OFF A FEW SHOWERS AND THUNDERSTORMS. RIGHT NOW
THINK THE MOST LIKELY AREAS WILL BE EAST AND SOUTH OF THE MAJOR
METROPLEX AIRPORTS. WILL CONTINUE WITH A VCTS AT WACO TOMORROW
AFTERNOON. OTHERWISE...NO SIGNIFICANT AVIATION CONCERNS OUTSIDE OF
ISOLATED AFTERNOON CONVECTION.
DUNN
&&
.UPDATE...
IT IS ANOTHER QUIET NIGHT ACROSS NORTH AND CENTRAL TEXAS.
ALTHOUGH THE ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTHEAST
TEXAS...SOUTHEAST OF A CENTER TO LUFKIN LINE...ARE MOVING
NORTHWEST...THEY WILL NOT MAKE IT INTO FORECAST AREA TONIGHT. WE
WILL SEE CLEAR TO PARTLY CLOUDY SKIES WITH LOWS IN THE 70S AREA
WIDE. WITH INCREASED MOISTURE TOMORROW...TEMPERATURES SHOULD BE
AT TO A FEW DEGREES LOWER THAN TODAY. NO CHANGES TO THE FORECAST
ARE PLANNED AT THIS TIME.
58
&&
.PREV DISCUSSION... /ISSUED 333 PM CDT MON AUG 25 2014/
IT IS A QUIET AND WARM DAY ACROSS THE REGION AS WE AWAIT OUR NEXT
WEATHER SYSTEMS. THE UPPER LEVEL RIDGE THAT HAS BEEN DOMINATING OUR
WEATHER PATTERN THE LAST FEW DAYS HAS MOVED TO OUR NORTHEAST AND WILL
REMAIN CENTERED TO OUR NORTHEAST AS A TUTT LOW IN THE NORTHERN
GULF OF MEXICO MOVES WEST TOWARDS THE TEXAS COAST. THIS FEATURE IS
SCHEDULED BY MOST OF THE MODELS TO APPROACH THE TEXAS COAST
TUESDAY AFTERNOON BUT THE RAP IS INDICATING A MUCH SLOWER MOVEMENT
OF THE TUTT. IN ADDITION...THE TRACK OF THE TUTT APPEARS TO BE
SLIGHTLY FURTHER SOUTH THAN PREVIOUS MODEL RUNS. DESPITE
THIS...RICH TROPICAL MOISTURE WILL STILL MOVE WEST AND NORTHWEST
INTO THE REGION STARTING TUESDAY AND THE UPPER LEVEL RIDGE WILL
WEAKEN SOME OVER THE REGION. THIS WILL ALLOW ISOLATED TO SCATTERED
CONVECTION TO DEVELOP ACROSS THE REGION TOMORROW AFTERNOON.
COVERAGE IS NOT EXPECTED TO BE VERY HIGH SO KEPT RAIN CHANCES AT
20 PERCENT ACROSS THE EAST AND SOUTHEAST WITH JUST AN ISOLATED
MENTION ELSEWHERE. GUSTY WINDS...LIGHTNING AND BRIEF HEAVY RAIN
WILL BE POSSIBLE WITH ANY THUNDERSTORMS.
ON WEDNESDAY...WE WILL REMAIN IN A TRANSITION PERIOD AS AN UPPER
LEVEL TROUGH MOVES ACROSS THE WESTERN CONUS. THIS TROUGH WILL HELP
TO FURTHER PUSH THE RIDGE TO THE EAST. ISOLATED TO SCATTERED
CONVECTION WILL BE POSSIBLE ON WEDNESDAY AS RICH ATMOSPHERIC
MOISTURE REMAINS IN PLACE. ON THURSDAY THE UPPER LEVEL TROUGH
MOVES INTO THE PLAINS. PREVIOUS MODEL RUNS WERE IN DECENT
AGREEMENT ON THE SPEED OF THE TROUGH BUT THE LATEST RUNS HAVE
AGAIN STARTED TO DIVERGE FROM EACH OTHER. AS THE TROUGH APPROACHES
FROM THE WEST ON THURSDAY...ISOLATED TO SCATTERED CONVECTION WILL
AGAIN OCCUR IN THE AFTERNOON AND EVENING HOURS WITH BETTER
COVERAGE LIKELY IN THE SOUTHEAST WHERE THE MOISTURE WILL BE
HIGHER...AND IN THE NORTHWEST CLOSER TO THE APPROACHING TROUGH.
OUR BEST RAIN CHANCES WILL BE FRIDAY AND/OR SATURDAY DEPENDING ON
THE SPEED OF THE TROUGH. THE GFS IS THE FASTEST OF THE EXTENDED
MODELS WITH THE ECMWF THE SLOWEST OF THE MODELS. BECAUSE OF THE
DISCREPANCIES...HAVE LINGERED POPS INTO SUNDAY AND ENDED THEM
FROM WEST TO EAST THROUGH THE DAY. IF THE GFS IS REALIZED AND THE
TROUGH IS OFF TO OUR NORTHEAST BY SATURDAY NIGHT...THE RAIN
CHANCES WILL END EARLIER. BENEFICIAL RAIN IS POSSIBLE WITH THIS
SYSTEM DEPENDING ON THE SPEED OF THE UPPER LEVEL TROUGH BUT SOME
LOCATIONS WILL BENEFIT FROM THE RAIN MORE THAN OTHERS.
WITH THE PATTERN CHANGE THIS WEEK...TEMPERATURES THROUGH MIDWEEK
WILL BE SLIGHTLY ABOVE NORMAL BUT BELOW 100 DEGREES. FOR THE
LATTER HALF OF THE WEEK...EXPECT NEAR OR SLIGHTLY BELOW NORMAL
TEMPERATURES.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 98 77 98 77 / 5 10 10 10 10
WACO, TX 75 98 74 98 74 / 5 10 10 10 10
PARIS, TX 73 95 72 95 71 / 5 20 20 10 10
DENTON, TX 76 97 74 97 73 / 5 10 10 10 10
MCKINNEY, TX 75 96 74 96 72 / 5 10 10 10 10
DALLAS, TX 80 98 78 98 77 / 5 10 10 10 10
TERRELL, TX 77 98 76 97 74 / 5 20 20 10 10
CORSICANA, TX 77 98 76 97 74 / 5 20 20 20 20
TEMPLE, TX 74 99 74 98 73 / 5 10 10 20 20
MINERAL WELLS, TX 74 98 73 98 74 / 10 10 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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
957 PM EDT WED AUG 27 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SOUTH INTO THE REGION TONIGHT AND
STALL ACROSS OUR AREA THROUGH THURSDAY AND FRIDAY...PROVIDING THE
FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS. THE FRONT WILL
LIFT NORTH AGAIN FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 945 PM EDT WEDNESDAY...
WATCHING A BROKEN LINE OF THUNDERSTORMS APPROACHING FROM THE
NORTHWEST. HRRR 23Z RUN SHOWS SOME OF THIS ACTIVITY REACHING
WESTERN GREENBRIER COUNTY. ADDED SLIGHT CHANCE TO CHANCE POPS FOR
THE NEXT FEW HOURS ALONG WITH ADDING THUNDER TO THE GRIDS. BUMPED
UP CLOUD COVER ACROSS THIS AREA AS WELL.
AS OF 225 PM EDT WEDNESDAY...
NOT SEEING MUCH IN THE WAY OF SHRA DEVELOPMENT THIS AFTERNOON.
BEST CU FIELD LIES FROM THE MTNS OF GREENBRIER COUNTY NEWD ALONG
THE ALLEGHANY FRONT. INSTABILITY IS MARGINAL WITH BEST SITUATED
ACROSS KY INTO OHIO AND PA. WILL KEEP ISOLATED THREAT OF SHRA/TSRA
THIS EVENING ACROSS THE WRN FRINGES OF SE WV/FAR SW VA AND BATH
VA. MAINLY LOOKING AT CLEAR SKIES ELSEWHERE BUT MOISTURE IS
STARTING TO INCREASE AS NOTED BY DEWPOINTS ASCENDING INTO THE 60S.
LOW TEMPS AS SUCH ARE GOING TO BE MILDER THAN PREVIOUS SEVERAL
NIGHTS WITH LOWS IN THE MID TO UPPER 50S MOUNTAIN VALLEYS TO MID 60S
PIEDMONT.
BACKDOOR FRONT WILL SHIFT ACROSS THE VA/NC BORDER LATE TONIGHT/THU
MORNING. MODELS SHOW AXIS OF CONVERGENCE TO ALIGN ACROSS THE NC MTNS
INTO THE PIEDMONT OF VA TOMORROW AFTERNOON AND THIS WILL BE WHERE
TSRA WILL FORM...BUT COVERAGE WILL BE SCATTERED AT BEST...SO KEPT
POPS IN THE 20/30 RANGE. MAINLY DRY NORTH OF A BLF-ROA LINE.
CLOUDS WILL BE SCATTERED/BKN AFTER ANY MORNING FOG LIFTS...WITH
HIGHS SURGING INTO THE 80S MOST AREAS WITH LOWER 90S SOUTHEAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 330 PM EDT WEDNESDAY...
MODELS ARE IN GOOD AGREEMENT THAT A WEAK FRONT WILL BE STALLED
ACROSS NORTHERN NORTH CAROLINA THURSDAY NIGHT AND FRIDAY...PROVIDING
THE FOCUS FOR SHOWER ACTIVITY...POSSIBLY WITH A FEW THUNDERSTORMS
DEVELOPING FRIDAY AFTERNOON/EVENING WITH DAYTIME HEATING. CANNOT
IDENTIFY WITHIN THE MODEL DATA ANY STRONG DISTURBANCES RIDING ALONG
THE FRONT...SO BELIEVE THE RAINFALL WILL BE OF THE LIGHT AND
OCCASIONAL VARIETY.
LOW PRESSURE PASSING ACROSS THE GREAT LAKES WILL DRAW THE FRONTAL
BOUNDARY BACK TO THE NORTH AS A WARM FRONT FRIDAY NIGHT...WITH WEAK
HIGH PRESSURE BUILDING BACK ACROSS OUR AREA ON SATURDAY FROM THE
CAROLINAS. CANNOT RULE OUT A FEW SHOWERS OR STORMS DEVELOPING ACROSS
THE MOUNTAINS DURING SATURDAY AFTERNOON AND EVENING...BUT THE DIP IN
ATMOSPHERIC MOISTURE ASSOCIATED WITH THE HIGH WILL KEEP THIS
ACTIVITY RATHER ISOLATED.
SATURDAY NIGHT...SOUTHWESTERLY FLOW WILL BECOME FIRMLY REESTABLISHED
AS UPPER LEVEL RIDGING RESIDES ACROSS THE SOUTHEAST STATES...WHILE
AN UPPER LEVEL TROUGH MOVES TOWARDS THE GREAT LAKES. AS SUCH...
EXPECT ATMOSPHERIC MOISTURE TO RAMP UP OVERNIGHT THANKS TO A DIRECT
WINDFLOW OFF THE GULF OF MEXICO. CLOUD COVER WILL INCREASE AFTER
SUNSET...WITH A FEW SHOWERS ENTERING THE MOUNTAINS TOWARD SUNRISE
SUNDAY.
TEMPERATURES THROUGH THE PERIOD WILL BE CLOSER TO NORMAL FOR LATE
AUGUST THANKS TO INCREASED CLOUD COVER/MOISTURE POOLING ALONG THE
FRONT. LOOK FOR HIGHS TO REACH INTO THE 80S MOST LOCATIONS FRIDAY
AND SATURDAY...WHILE OVERNIGHT LOWS WILL BE MILDER THAN PREVIOUS
NIGHTS...GENERALLY HOLDING IN THE 60S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 PM EDT WEDNESDAY...
DEEP GULF MOISTURE FLOWING NORTH ALONG THE APPALACHIAN CHAIN WILL
MAINTAIN A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY FOR THE
EARLY HALF OF NEXT WEEK.
FOR SUNDAY...RAINFALL IS LOOKING INCREASINGLY LIKELY AS AN
UPPER LEVEL TROUGH MOVES UP THE OHIO RIVER VALLEY. WITH
PERCEPTIBLE WATER VALUES IN THE BALLPARK OF 2 INCHES ACROSS OUR
AREA...BELIEVE THAT LOCALLY EXCESSIVE RAINFALL WILL BE POSSIBLE IN
SOME AREAS... ESPECIALLY IF STORMS BEGIN TO PASS REPEATEDLY OVER
THE SAME LOCATIONS.
ON MONDAY...UPPER LEVEL FLOW BEGINS TO TRANSITION TO A MORE WEST TO
EAST ORIENTATION...WITH NO STRONG DISTURBANCES EXPECTED. BELIEVE
SHOWER AND THUNDERSTORM ACTIVITY WILL BE MORE DRIVEN BY DAYTIME
HEATING THAN ANYTHING ELSE...MEANING RAINFALL WILL BE MORE OF THE
HIT AND MISS VARIETY.
LOOKING TO TUESDAY...EXPECT A SLIGHTLY BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS AS A COLD FRONT APPROACHES OUR REGION FROM THE
NORTHWEST. BEST CHANCES FOR SHOWER AND THUNDERSTORM ACTIVITY WILL BE
DURING THE EVENING AS THE FRONT APPROACHES THE OHIO RIVER...HOWEVER
WITH NO REAL PUSH OF COLD AIR BEHIND THE FRONT...IT IS ENTIRELY
POSSIBLE THAT THE OHIO RIVER IS AS FAR SOUTH AS THE FRONT SINKS.
ABUNDANT GULF MOISTURE WILL MAKE FOR MUGGY AND WARM CONDITIONS FOR
THE EARLY HALF OF NEXT WEEK. LOOK FOR HIGHS TO RANGE FROM THE UPPER
70S/LOW 80S ACROSS THE MOUNTAINS...TO THE UPPER 80S ACROSS THE
PIEDMONT. OVERNIGHT LOWS WILL RANGE FROM THE MID 60S TO LOW 70S.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
AS OF 815 PM EDT WEDNESDAY...
BKN LINE OF SHRA/TSRA FROM MGW-LEX...APPROACHING FROM THE
NORTHWEST...EXPECTED TO WEAKEN AND DISSIPATE B4 MIDNIGHT. DEBRIS
CLOUDINESS...BASES AOA 10KFT...MAY PASS THROUGH SOUTHERN WV INTO
SOUTHERN VA OVERNIGHT. CURRENT THINKING IS DEBRIS CLOUDINESS WILL
BE PRETTY THIN...THUS PROMOTING ANOTHER GOOD RADIATIONAL COOLING
NIGHT WITH FORMATION OF RIVER VALLEY FOG IN THE MOUNTAIN VALLEYS.
THIS WILL MAINLY IMPACT KLWB/KBCB WHERE IFR/LIFR CONDITIONS
POSSIBLE FOR A FEW HOURS TOWARD DAYBREAK THURSDAY...ANY
FOG/STRATUS LIFTING MID MORNING.
WEAK SURFACE COLD FRONT WILL CROSS THE FORECAST AREA EARLY
THURSDAY...THEN BECOME STATIONARY ACROSS NORTH CAROLINA LATE
THURSDAY INTO FRIDAY. CONVERGENCE ALONG THE FRONT WILL PERMIT
SCATTERED SHRA/TSRA AGAIN THURSDAY AFTERNOON. POSITION OF FRONT BY
THAT TIME SUGGESTS SHRA/TSRA ACTIVITY WILL DEVELOP VCNTY OF THE
VA/NC BORDER...THEN DRIFT SOUTHEAST INTO NORTH CAROLINA WITH THE
MEAN WIND WHICH WILL BE OUT OF THE NORTHWEST.
SCT-BKN CU SEEMS LIKE THE MOST LIKELY SCENARIO ACROSS THE
VIRGINIAS THURSDAY AFTERNOON...TOWERING CU LIMITED TO THE FRONTAL
ZONE WHICH WILL BE DRIFTING INTO NORTH CAROLINA. BEHIND THE FRONT
WINDS WILL GENERALLY BE OUT OF THE NORTHWEST...4-7KTS AT THE MOST.
EXTENDED DISCUSSION...
THE WEAK SURFACE COLD FRONT IS FORECAST TO STALL OVER THE
CAROLINAS THURSDAY NIGHT...REMAIN NEARLY STATIONARY FRIDAY...THEN
RETURN NORTH AS A WARM FRONT SATURDAY. WIDELY SCATTERED SHRA/TSRA
ARE EXPECTED ALONG THIS BOUNDARY FRIDAY AND SATURDAY...WITH THE
GREATEST COVERAGE DURING THE PEAK HEATING OF THE DAY. WHERE
SHRA/TSRA OCCUR BRIEF PERIOD OF SUB VFR CONDITIONS CAN BE
EXPECTED.
AN AREA OF LOW PRESSURE IS FORECAST TO MOVE THROUGH THE GREAT
LAKES SATURDAY NIGHT AND SUNDAY...THE ASSOCIATED COLD FRONT
TRAILING SOUTH AND MOVING ACROSS THE OHIO/TN VALLEYS. SHOWERS AND
THUNDERSTORMS WILL LIKELY BE ASSOCIATED WITH THIS FRONT...THIS
ACTIVITY SPREADING EAST INTO THE CENTRAL APPALACHIANS SUNDAY AND
MONDAY. SHOWER COVERAGE SUNDAY/MONDAY IS EXPECTED TO BE MUCH MORE
WIDESPREAD AS COMPARED TO FRIDAY AND SATURDAY. AS SUCH...THE FIRST
HALF OF THE HOLIDAY WEEKEND LOOKS MORE FAVORABLE TO VFR FLYING
COMPARED TO THE SECOND HALF.
&&
.EQUIPMENT...
AS OF 1130 AM EDT WEDNESDAY ...
THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL
AIRPORT...REMAINS OUT OF SERVICE. A PART HAS BEEN ORDERED BUT
APPEARS REPAIRS WILL NOT BE DONE UNTIL THIS FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...CF/WP
SHORT TERM...NF
LONG TERM...NF
AVIATION...PM
EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
905 PM CDT WED AUG 27 2014
.UPDATE...
NEW GUIDANCE ROLLING IN IS SHOWING DRY AIR HOLDING STRONG ACROSS
THE AREA A BIT LONGER INTO THURSDAY AS HIGH PRESSURE IS SLOW TO
EXIT AND LOW PRESSURE IS SLOWER TO ARRIVE FROM THE SOUTHWEST. THE
NAM AND RAP SOUNDINGS SHOW A VERY DEEP DRY LAYER AND THEY ARE
HOLDING OFF PRECIP FOR THE WESTERN AREAS UNTIL AFTER 18Z. HAVE
ALREADY TRIMMED BACK POPS AND WILL LET THE NEXT SHIFT MAKE FURTHER
ADJUSTMENTS WITH THE FULL SUITE OF DATA LATER ON. OTHERWISE...NO
MAJOR UPDATES NEEDED FOR THE OVERNIGHT. THE MID DECK OF CLOUDS
THAT WAS OVER US HAS EVAPORATED...LEAVING SKIES MOSTLY CLEAR FOR A
WHILE. THIS COULD LEAD TO SOME PATCHY FOG...BUT DON/T EXPECT IT TO
GET OUT OF HAND.
&&
.AVIATION/06Z TAFS/...
LOOK FOR QUIET WEATHER ACROSS THE TAF SITES THROUGH THE LATE
AFTERNOON ON THURSDAY. THE NEW MODEL GUIDANCE ROLLING IN IS
DELAYING THE ONSET OF SHOWERS AND POSSIBLE THUNDERSTORMS WITH AN
APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTHWEST. LOOK FOR VFR
CONDITIONS THROUGH AT LEAST 00Z FRI AT KMSN AND PROBABLY THROUGH
03-06Z AT KMKE/KENW/KUES. CIGS WILL GRADUALLY LOWER THROUGH THE
AFTERNOON ON THURSDAY AS MOISTURE STREAMS IN. LOOK FOR WINDS TO BE
EASTERLY THROUGH THE TAF PERIOD AND GENERALLY LESS THAN 10 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 412 PM CDT WED AUG 27 2014/
SHORT TERM...
TONIGHT AND THURSDAY...FORECAST CONFIDENCE IS HIGH.
MODELS ARE IN GOOD AGREEMENT WITH HIGH PRESSURE MOVING EAST
SOUTHEAST INTO NORTHERN LOWER MICHIGAN BY 12Z THURSDAY. DRY AIR
ASSOCIATED WITH THE HIGH WILL KEEP THE AREA DRY TONIGHT. THERE WILL
BE MIDDLE TO HIGH CLOUDS THAT CONTINUE TO STREAM EASTWARD INTO THE
AREA. THERE MAY BE SOME FOG IN THE WISCONSIN RIVER VALLEY...BUT THE
CLOUDS MAY LIMIT THIS. LOWS SHOULD BE IN THE UPPER 50S TO LOWER 60S
ACROSS MOST OF THE AREA.
MODELS ARE IN GOOD AGREEMENT WITH KEEPING BEST UPWARD VERTICAL
MOTION AND MOISTURE CONVERGENCE ASSOCIATED WITH 850 MB LOW LEVEL JET
NOSE TO THE NORTHWEST OF THE AREA THURSDAY AFTERNOON. THE MORNING
MAY END UP BEING DRY AS WELL WITH INFLUENCE OF HIGH TO THE NORTHEAST
OF THE AREA. FOR NOW...KEPT POPS IN THE AREA THURSDAY MORNING PER
COLLABORATION WITH NEIGHBORING OFFICES.
BROUGHT IN HIGH POPS IN THE AFTERNOON IN THE WESTERN COUNTIES...AS
THIS AREA GETS BRUSHED BY DECENT UPWARD VERTICAL MOTION/MOISTURE
CONVERGENCE WITHIN FOCUSED WARM AIR ADVECTION AND 850 MB LOW LEVEL
JET. PRECIPITABLE WATER VALUES OF 1.80 TO 2.00 INCHES IN THAT AREA
SUGGEST LOCALLY HEAVY RAINFALL IS POSSIBLE WITH ANY STORMS.
KEPT HIGHS IN THE UPPER 60S TO LOWER 70S WITH EXPECTED CLOUDS AND
PRECIPITATION.
THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM.
ONGOING CLUSTER OF TSTORMS OVER SW AND WEST CENTRAL WI THU EVENING WILL
BE DRIVEN NEWD INTO CENTRAL AND NRN WI ON THE NOSE OF A NWD
MOVING LOW LEVEL JET STREAM AND SFC WAVE. LIKELY OR CATEGORICAL
POPS ARE FORECAST OVER PORTIONS OF THE NRN AND WRN CWA. OTHERWISE
SCT TSTORMS EXPECTED WITH THE WARM...MOIST ADVECTION OVER THE
REMAINDER OF THE CWA. THE CLUSTER OF STORMS WILL BE PROGRESSIVE SO
FLASH FLOOD THREAT IS VERY LOW OVER THE FAR NWRN CWA.
THE REMAINING SW-NE TROUGH OF LOW PRESSURE WILL ACT AS A
STATIONARY FRONT OVER CENTRAL AND SRN WI FOR FRI-SAT. ANOTHER AREA
OF CONVECTION SHOULD REDEVELOP ALONG THE FRONT FRI AFT/EVE AS A
SHORTWAVE TROUGH SLOWLY APPROACHES FROM THE WEST. INTERMITTENT
CONVECTION WILL CONTINUE FRI NT INTO SAT AS THE SHORTWAVE TROUGH
AND VERY SLOW MOVING FRONT MOVE ACROSS SRN WI. PWS REMAIN HIGH
FROM 1.70-1.90 INCHES WHILE CORFIDI MAGNITUDES ARE ONLY 5 KTS. THE
MEAN STORM MOTION HOWEVER IS SWLY AT 25-35 KTS FOR FRI AFT/NIGHT
BUT DECREASES TO 15-25 KTS FOR SAT. SOME FLASH FLOOD THREAT WOULD
EXIST FOR ANY AREAS THAT RECEIVE REPEATED ROUNDS OF TSTORMS...BUT
OVERALL FRONTAL LIFT IS WEAK WITH UNCERTAINTY ON PROLONGED
CONVECTION OVER SUFFICIENTLY LARGE AREAS. CONTINUED THE ESF TO
HIGHLIGHT THE HEAVY RAIN THREAT AND THE POTENTIAL FOR RIVERS TO
RISE THIS WEEKEND.
LONG TERM...
SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
A VERY WEAK AREA OF HIGH PRESSURE WILL QUICKLY MOVE ACROSS THE
AREA LATE SAT NT AND SUN AM. SLY FLOW WILL THEN DEVELOP ONCE AGAIN
FOR SUN AFT AND EVE AS STRONG LOW PRESSURE DEVELOPS OVER SRN
CANADA WITH A STRONG TRAILING COLD FRONT. THE COLD FRONTAL
PASSAGE WILL OCCUR ON MONDAY WITH LIKELY POPS FORECAST. A DRY AND
PLEASANT AIRMASS WITH THEN PREVAIL FOR TUE-WED.
AVIATION/00Z TAFS/...
VFR CONDITIONS ARE EXPECTED AT TAF SITES FOR MOST OF TONIGHT AND
THURSDAY. LIGHT NORTHEAST WINDS WILL GRADUALLY SHIFT EAST
TONIGHT...THEN EAST TO SOUTHEAST ON THURSDAY. MIDDLE TO HIGH CLOUDS
WILL INCREASE AND CONTINUE TO MOVE THROUGH THE AREA TONIGHT INTO
THURSDAY.
LIGHT WINDS TONIGHT MAY GET LIGHT ENOUGH FOR LIGHT FOG AT MADISON
AND KENOSHA...MAINLY BETWEEN 09Z AND 13Z THURSDAY. HOWEVER...LEFT
OUT OF TAFS DUE TO LOW CONFIDENCE GIVEN INCREASING CLOUDS. SOME
SHOWER AND THUNDERSTORM ACTIVITY COULD REACH MADISON AT TIMES
THURSDAY AFTERNOON. GIVEN SOME UNCERTAINTY WITH EXACT TIMING...WILL
HOLD OUT OF TAFS FOR NOW. LATER FORECASTS MAY ADD VICINITY THUNDER
WORDING THERE DURING THAT TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/THURSDAY AND AVIATION/MARINE...WOOD
THURSDAY NIGHT THROUGH WEDNESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
642 PM CDT WED AUG 27 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 328 PM CDT WED AUG 27 2014
FORECAST FOCUS IS ON PRECIPITATION TIMING AND AMOUNTS...THREAT
FOR HEAVY RAIN WITH LOCALIZED FLOODING.
AS OF MID AFTERNOON...WATER VAPOR IMAGERY OVERLAID WITH RAP 500
MB HEIGHTS SHOWED DECAYING DISTURBANCE ACROSS IOWA...WITH MAIN
CLOSED LOW ROTATING INTO NORTHWESTERN COLORADO. WEAK IMPULSES WERE
RIDING THE PERIPHERY OF THE TROUGH...AND IT IS THESE IMPULSES THAT
WILL BE THE PLAYERS FOR THE NEXT 24 TO 48 HOURS ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY.
AT THE SURFACE...LINGERING SHOWERS AND THUNDERSTORMS HAVE BEEN
CONFINED TO SOUTHERN AND SOUTHWESTERN IOWA...KEEPING FRONTAL
BOUNDARY ACROSS SOUTHERN IOWA / NORTHERN MISSOURI. THE 65F
DEWPOINT LINE IS GENERALLY SOUTH OF I-80.
THE LARGEST CHANGES TO ONGOING FORECAST HAVE BEEN RELATED TO
PRECIPITATION TIMING...AS 27.12Z MODEL CYCLES TREND TOWARD A LATER
ARRIVAL OF THE GREATEST 850MB MOISTURE TRANSPORT OVERNIGHT THROUGH
THE DAY ON THURSDAY. MOST OF THE DETERMINISTIC AND HI-RES MODELS
SHOW A SHIELD OF RAIN SHOWERS WITH EMBEDDED THUNDERSTORMS REACHING
NORTHEAST IOWA / SOUTHEAST NOT UNTIL THE EARLY MORNING HOURS /4 TO
6 AM/ THEN MOVING INTO WESTERN WISCONSIN MID TO LATE MORNING.
PRECIPITATION CHANCES HAVE BEEN ADJUSTED...BUT OVERALL CONFIDENCE
REMAINS VERY HIGH SO KEPT 90 TO 100 CHANCES.
THE NOSE OF THE 850MB MOISTURE TRANSPORT LIFTS THROUGH THE AREA
DURING THE DAY...SO ANY COMPLEX OF SHOWERS/STORMS WILL LIKELY BE
PROGRESSIVE. HOWEVER...THE ATMOSPHERE WILL INCREASINGLY BECOME
MORE FAVORABLE FOR HEAVY RAINFALL RATES...AS PWATS APPROACH 2
INCHES. WARM CLOUD DEPTHS EXCEED 4 KM ACROSS MUCH OF THE AREA. THE
STORM TOP WINDS ARE PROGGED TO BE 25 TO 30 KTS...WHICH SHOULD HELP
KEEP CONVECTION PROGRESSIVE ENOUGH. THOUGH WITH BROAD WARM AIR
ADVECTION AND ISENTROPIC LIFT DURING THE DAY...HAVE KEPT HIGH
PRECIPITATION CHANCES THROUGH THE EVENING HOURS. THE GREATER FOCUS
SEEMS TO BE ON WESTERN INTO NORTH CENTRAL WISCONSIN...THOUGH MOST
AREAS WILL SEE SHOWERS/STORMS THROUGHOUT THE DAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 328 PM CDT WED AUG 27 2014
THE MAIN 500MB SHORTWAVE BEGINS TO SWING THROUGH THE UPPER
MIDWEST FRIDAY EVENING INTO SATURDAY MORNING...WITH THE GREATEST
500-300MB PV ADVECTION ALIGNED FROM CENTRAL AND EASTERN IOWA INTO
SOUTHERN WISCONSIN. THE MOIST AIRMASS WILL LINGER THROUGH THIS
PERIOD AS WELL...AS THE OVERALL ENVIRONMENT SUPPORTS EFFICIENT
RAIN PRODUCES. THE SURFACE FRONT WILL LIKELY STALL FROM IOWA INTO
SOUTHERN WISCONSIN AND COULD BE THE FOCUS FOR SEVERAL EPISODES FOR
SHOWERS/STORMS. DEPENDING ON THE HEAVY RAINFALL OUTCOME IN ROUND
ONE...THIS PERIOD WILL NEED TO BE WATCHED FOR REPEATED ROUNDS.
THOUGH AT THIS POINT...IT LOOKS LIKE DIFFERENT AREAS WILL SEE THE
ROUNDS OF HEAVIER RAINFALL.
IT DOES LOOK LIKE BY SATURDAY MOST OF THE UPPER LEVEL ENERGY
MOVES EAST...AND THE PRECIPITATION CHANCES ARE CONFINED TO
SOUTHERN AND CENTRAL WISCONSIN. FOR THOSE PLANNING ACTIVITIES THIS
UPCOMING HOLIDAY WEEKEND...THE SATURDAY NIGHT TO SUNDAY MORNING
TIMEFRAME HAS THE GREATEST LIKELIHOOD TO SEE DRIER PERIODS.
SUNDAY THROUGH MONDAY WILL FEATURE AN APPROACHING UPPER LEVEL
SHORTWAVE FROM THE NORTHERN PLAINS. 27.12Z MODELS ALREADY SHOW
THIS FEATURE TO BE A BIT VIGOROUS AS IT SWINGS THROUGH. AT THE
SURFACE...THIS WILL DRIVE A COLD FRONT THROUGH THE UPPER MIDWEST.
THERE REMAINS SOME TIMING DIFFERENCES BETWEEN THE GFS/ECMWF/GEM
BUT THE TREND HAS BEEN FOR THE FRONTAL PASSAGE TO BE LATE SUNDAY
NIGHT OR EARLY MONDAY MORNING. SEVERE CHANCES LOOK LIMITED RIGHT
NOW GIVEN TIMING BUT 500 TO 1000 MUCAPE TRANSLATES AHEAD OF THE
FRONT WITH MARGINAL 0-6KM SHEAR VALUES /20 KTS/. SOMETHING TO KEEP
AN EYE WITH THE HOLIDAY WEEKEND...ESPECIALLY IF THE TIMING BECOMES
MORE FAVORABLE DURING PEAK HEATING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 642 PM CDT WED AUG 27 2014
27.18Z FORECAST GUIDANCE HAS SLOWED NORTHEAST PROGRESSION OF
SHOWERS AND THUNDERSTORMS THURSDAY MORNING AND THUS DELAYED ONSET
OF -SHRA/TSRA AT BOTH SITES BY A COUPLE HOURS. IF CURRENT TRENDS
CONTINUE...RAIN MAY HOLD OFF UNTIL LATE THURSDAY MORNING. STILL
EXPECT VFR CONDITIONS OVERNIGHT WITH INCREASING MID-LEVEL CLOUD
COVER AND LIGHT WIND WITH A SLIGHT SOUTHEAST DIRECTIONAL PREFERENCE.
CEILINGS/VISIBILITY WILL LOWER WITH SHOWERS AND THUNDERSTORMS...
DIPPING AT TIMES INTO THE MVFR/IFR RANGE BY THURSDAY AFTERNOON...
ESPECIALLY DURING PERIODS OF HEAVY RAINFALL.
&&
.HYDROLOGY...THURSDAY THROUGH FRIDAY NIGHT
ISSUED AT 328 PM CDT WED AUG 27 2014
VERY FAVORABLE SETUP FOR EFFICIENT...HEAVY RAIN PRODUCERS OVER
THE NEXT FEW DAYS. WARM CLOUD DEPTHS CONTINUE TO HOVER NEAR 4000 M
/IF NOT HIGHER/ WHILE PWATS PEAK AROUND 2 INCHES THURSDAY-
THURSDAY NIGHT. HEAVIER RAIN SIGNALS ARE PROGRESSIVE...THROUGH
NORTHERN IOWA INTO SOUTHEAST MINNESOTA AND THEN NORTH CENTRAL
WISCONSIN. FOR ROUND TWO...THE HIGHER THREAT LOOKS TO BE ACROSS
EASTERN IOWA INTO SOUTHERN WISCONSIN.
RUN TOTAL QPF FROM THE EC/GFS/GEM THROUGH SATURDAY RANGE FROM 2
TO 4 INCHES. LOCALLY HIGHER AMOUNTS ARE LIKELY. AT THIS
MOMENT...THINK THERE COULD BE QUICK RISES ON SOME RIVERS...BUT
SHOULD STAY WITHIN BANK. AS ALONG AS STORMS MOVE...AND AREAS DON/T
GET REPEATED HITS...THE FLASH FLOOD THREAT IS REDUCED. ALL
SAID...WITH THE HIGH LIKELIHOOD OF HEAVY RAIN...AND THE POTENTIAL
FOR SIGNIFICANT AMOUNTS...WILL MAINTAIN HYDROLOGIC OUTLOOK TO
HIGHLIGHT THE THREATS. A FLASH FLOOD WATCH MAY BE NECESSARY IF
SIGNALS ARE FOR THE ROUNDS OF HEAVY RAINFALL LOOK TO REPEAT OVER
THE SAME AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...ROGERS
HYDROLOGY....ZT/RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1138 PM CDT MON AUG 25 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 254 PM CDT MON AUG 25 2014
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS AFTERNOON SUGGESTS THE COLD FRONT IS MAKING
SLOW EASTWARD PROGRESS THROUGH THE WESTERN SECTIONS OF THE
FORECAST AREA. DEW POINTS REMAIN IN THE 70S AHEAD OF THE FRONT BUT
THEN DROP OFF INTO THE 50S ACROSS CENTRAL MINNESOTA. LOCAL AND
REGIONAL RADARS SHOW THE LINE OF STORMS THAT MOVED THROUGH
OVERNIGHT EXTEND FROM SOUTHEAST WISCONSIN INTO EASTERN IOWA AND
ARE STARTING TO INTENSIFY AGAIN.
THE EXPECTATION THROUGH THE REST OF THE AFTERNOON INTO THE EVENING
IS THAT THE ONGOING ACTIVITY WILL CONTINUE TO MOVE AWAY FROM THE
AREA AS THE FRONT PROGRESSES THROUGH THE FORECAST AREA. SOME
ADDITIONAL ACTIVITY FORMING ON THE WESTERN PART OF THE FRONT OVER
THE MISSOURI RIVER VALLEY. THE 25.17Z HRRR SUGGESTS THIS WILL
TRACK INTO CENTRAL IOWA BEFORE DIMINISHING. HOWEVER...CONFIDENCE
IN THIS MODEL OUTPUT IS NOT THAT HIGH. OUTPUT FROM THE 25.15Z
HOP-WRF DOES SUGGEST THIS MAY SURVIVE AND COME ACROSS NORTHEAST
IOWA THIS EVENING AND WILL SHOW SOME SMALL RAIN CHANCES FOR THIS.
ADDITIONAL CONVECTION SHOULD FORM OVERNIGHT ALONG THE COLD FRONT
AS A SHORT WAVE TROUGH COMES OUT OF THE CENTRAL ROCKIES. THE
MOISTURE TRANSPORT INTO THE FRONT DOES NOT LOOK TO BE ALL THAT
STRONG TONIGHT AND AS CANADIAN HIGH PRESSURE BUILDS IN FROM THE
NORTH...THE BULK OF THE RAIN TONIGHT SHOULD REMAIN OVER CENTRAL
AND SOUTHERN IOWA.
THE HIGH WILL GRADUALLY MOVE EAST-SOUTHEAST ACROSS THE UPPER
MIDWEST AND BE OVER THE U.P. OF MICHIGAN BY WEDNESDAY NIGHT. THIS
IS EXPECTED TO KEEP THE FRONT FAR ENOUGH SOUTH THAT MOST OF THE
CONVECTION ALONG IT FROM TUESDAY THROUGH WEDNESDAY SHOULD STAY TO
THE SOUTH. CANNOT RULE OUT THE SOUTHERN PARTS OF THE FORECAST AREA
GETTING CAUGHT ON THE NORTH EDGE OF THE COMPLEXES THAT FORM ALONG
THE FRONT AND WILL SHOW SOME 20 TO 40 PERCENT RAIN CHANCES FOR
THIS SCENARIO.
BY WEDNESDAY NIGHT THE HIGH WILL START TO MOVE FARTHER OFF TO THE
EAST ALLOWING DEEPER MOISTURE TO START RETURNING TO THE AREA. THIS
MOISTURE RETURN SHOULD OCCUR AHEAD OF STRONGER SHORT WAVE TROUGH
EJECTING NORTHEAST OUT OF THE CENTRAL ROCKIES. THIS WAVE SHOULD
BRING AT LEAST SOME WEAK PV ADVECTION IN THE 500-300 MB LAYER INTO
THE AREA ALONG WITH 1 TO 3 UBAR/S OF UP GLIDE ON THE 310K
ISENTROPIC SURFACE. SHOULD SEE ACTIVITY DEVELOP TO THE
WEST/SOUTHWEST OF THE AREA WEDNESDAY EVENING AND THEN MOVE IN
DURING THE OVERNIGHT HOURS.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 254 PM CDT MON AUG 25 2014
THE SHORT WAVE TROUGH THAT COMES OUT WEDNESDAY NIGHT WILL TRACK
ACROSS THE UPPER MIDWEST THURSDAY AND SHOULD BE THE FIRST OF
SEVERAL WAVES AS THE MEAN LONG WAVE TROUGH SLOWLY MOVES EAST AS IT
BUMPS INTO THE RIDGING OVER THE EASTERN CONUS. DIFFERENCES BETWEEN
THE 25.12Z ECMWF AND GFS ON HOW FAST THE LONG WAVE TROUGH WILL
MOVE EAST WITH THE ECMWF BEING SLOWER THAN THE GFS. ALSO
DIFFERENCES ON HOW MUCH RIDGING WILL OCCUR BEHIND THIS LONG WAVE
TROUGH AHEAD OF THE NEXT SYSTEM MOVING ONTO THE PACIFIC NORTHWEST
COAST. WITH SUCH DIFFERENCES BETWEEN THE MODELS PLAN TO STAY WITH
THE MODEL CONSENSUS GRIDS AND SHOW RAIN CHANCES THROUGH MUCH OF
THE PERIOD WITH THE HIGHEST CHANCES THURSDAY AND THURSDAY NIGHT AS
THE FIRST SHORT WAVE TROUGH COMES ACROSS THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1138 PM CDT MON AUG 25 2014
WHILE SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED ACROSS THE REGION...RST AND LSE ARE EXPECTED TO STAY
MAINLY DRY AS THIS WAVE MOVES THROUGH. WINDS WILL REMAIN OUT OF
THE WEST AS A COLD FRONT DRIFTS THROUGH THE REGION AND HIGH
PRESSURE PUSHES IN FROM THE NORTHWEST. SOME RAIN AND STORMS MAY
MOVE IN LATE TUESDAY NIGHT...BUT IT MAINLY LOOKS LIKE IT WOULD BE
AFTER 6Z AND NOT INCLUDED ON THESE TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1145 PM MDT WED AUG 27 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 240 PM MDT WED AUG 27 2014
...FEW STRONG STORMS POSSIBLE LATER TODAY AND THIS EVENING...SOME
SNOW AT THE HIGHEST PEAKS...
CURRENTLY...
VERY WELL DEFINED UPPER LOW AS SEEN BY WATER VAPOR IMGY WAS SPINNING
OVER NE UTAH. A VORT LOBE FROM THIS SYSTEM WAS OVER WESTERN COLORADO
AS A LINE OF TSRA WAS ADVANCING EAST OVER THIS REGION. OVER THE NWS
PUB CWA...A DRY SLOT ASSOCIATED WITH THIS UPPER LVL LOW WAS OVER THE
WESTERN 1/2 OF THE PLAINS...AS SKIES WERE GENERALLY SUNNY. TEMPS
OVER THE PLAINS HAVE WARMED UP INTO THE 80S GENERALLY BELOW 5500
FEET...WITH 60S AND 70S MOST OTHER LOCATIONS. LOOKING AT THE
THERMODYNAMIC FIELDS...CAPE VALUES FROM THE SPC WERE IN THE 1000
RANGE WHILE FARTHER EAST VALUES WERE 2500 J/KG. EFFECTIVE DEEP SHEAR
WAS 30-35 KNTS.
AT THE SFC ACROSS THE REGION...A WEEK COOL FRONT WAS CLEARLY SEEN IN
THE VIS SAT PIX IMGY ALONG THE EL PASO/DOUGLAS/ELBERT COUNTY LINE
AND IT WAS PROGRESSING SLOWLY SWD.
REST OF THIS AFTERNOON AND EVENING...
VORT LOBE OVER W CO WILL LIKELY START AFFECTING THE GREATER PIKES
PEAK REGION LATE THIS AFTERNOON AND INTO THIS EVENING. HRRR REALLY
DOES NOT GET THINGS GOING UNTIL AFTER 9 PM...AND I BELIEVE THIS IS
TOO LATE AS THINGS WILL LIKELY GET GOING BY VERY LATE AFTERNOON OR
EARLY EVENING. AS MENTIONED ABOVE...SHEAR AND CAPE ARE INCREASING
AND I DO EXPECT WE WILL SEE A FEW SUPERCELLS OVER THE EASTERN PLAINS
OF COLORADO. SPC RECENTLY ISSUED AN MCD DISCUSSING THIS THREAT.
WALDO WILL ALSO NEED TO BE WATCHED. ALTHOUGH STORMS WILL MOVE AT A
GOOD CLIP TODAY...ATMOSPHERE HAS PLENTY OF MOISTURE AND ANY HEAVY
RAIN OVER A SHORT PERIOD OF TIME WILL CAUSE ISSUES OVER THE BURN
SCARS.
OVERALL...I BELIEVE BEST CHANCE OF SEVERE WILL GENERALLY BE ALONG
AND NORTH OF HIGHWAY 50...ASSOCIATED WITH SOUTHWARD MOVING
BOUNDARY...ALTHOUGH STRONG STORMS COULD OCCUR ANYWHERE ACROSS THE
REGION GIVEN THE MOISTURE AND DYNAMIC FORCING ASSOCIATED WITH THE
UPPER LOW HEADING OUR WAY.
TONIGHT...
UPPER LOW WILL BE OVER THE STATE. ISOLATED SHOWERS ARE LIKELY TO
CONTINUE THROUGHOUT THE NIGHT...BUT AS MENTIONED...BELIEVE THEY WILL
BE ISOLATED. BEST CHANCE WILL BE OVER THE CONTDVD REGION. SNOW
SHOWERS WILL OCCUR AT HIGHER ELEVATIONS WITH SOME LIGHT ACCUMS
LIKELY.
TOMORROW...
COOL NORTHEAST LLVL FLOW WILL PREVAIL OVER REGION. WITH UPPER LOW
OVERHEAD...ANTICIPATE SKIES WILL CLOUD UP RELATIVELY EARLY. ALTHOUGH
QUITE A FEW SHOWERS WILL LIKELY DEVELOP TOMORROW...OVERALL HEAVY
RAIN THREAT LOOKS LOW AT THIS TIME. IT WILL BE NOTICEABLY COOLER
TOMORROW ACROSS THE REGION AS HIGHS WILL ONLY BE IN THE 70S ALONG THE
I-25 CORRIDOR WITH TEMPS AOA 80F OVER THE FAR E PLAINS. 60S AND
70S ELSEWHERE ACROSS THE VALLEYS. IT WILL BE COOL ABOVE TREELINE
WITH HIGHS ONLY IN THE 30S AND 40S. SNOWSHOWERS WILL BE POSSIBLE.
OVERALL BEST CHANCE OF SHOWERS TOMORROW WILL BE ALONG THE EAST
FACING SLOPES OF THE EASTERN MTNS. /HODANISH
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 240 PM MDT WED AUG 27 2014
UPPER LOW FINALLY EXITS THE STATE EARLY FRI MORNING...WITH WEAK
CONVECTION ENDING FROM WEST TO EAST ACROSS THE REGION THU EVENING.
FLAT UPPER RIDGE THEN BUILDS ACROSS THE AREA FRI LEADING TO
MOSTLY DRY CONDITIONS AND SEASONABLY MILD TEMPS...ALTHOUGH SOME
ISOLATED WEAK TSRA MAY FORM OVER THE MTS IN THE AFTERNOON AS
RESIDUAL LOW LEVEL MOISTURE LINGERS. NEW WESTERN U.S. TROUGH
BEGINS TO MOVE ONSHORE DURING THE WEEKEND...WITH INCREASING W-SW
FLOW ACROSS COLORADO SAT INTO SUN. STILL A VERY SMALL CHANCE OF
SOME ISOLATED TSRA OVER THE HIGHER TERRAIN SAT AFTERNOON...THOUGH
AGAIN STORMS SHOULD BE HIGH BASED AND WEAK AS MOIST LAYER IS
FAIRLY SHALLOW. UPPER TROUGH THEN MOVES INTO THE NORTHERN HIGH
PLAINS SUN...PUSHING A COLD FRONT THROUGH COLORADO DURING THE
AFTERNOON. WITH NOSE OF THE UPPER JET MOVING ACROSS NORTHERN
COLORADO...STRONGEST UPWARD MOTION WILL LIKELY STAY NORTH OF THE
AREA...AND ONLY A SLIGHT CHANCE OF TSRA IS EXPECTED OVER THE
CENTRAL MTS AND FAR EASTERN PLAINS SUN AFTERNOON/EVENING. TEMPS
BOTH SAT AND SUN WILL CLIMB BACK ABOVE NORMAL...WITH WARMEST
READINGS JUST AHEAD OF THE COLD FRONT ON SUN.
WEAK LOW LEVEL MOISTURE RETURN DEVELOPS BEHIND THE FRONT ON
MON...THOUGH AIR MASS STAYS FAIRLY STABLE THROUGH THE DAY UNDER
SUBSIDENT UPPER FLOW BEHIND THE DEPARTING TROUGH. AS A
RESULT...SUSPECT ANY CONVECTION ON THE PLAINS WILL HAVE TO WAIT
FOR DEVELOPING WARM ADVECTIVE LIFT LATE MON NIGHT AS LOW LEVEL JET
DEVELOPS. ON TUE/WED...SHALLOW UPSLOPE FLOW WILL CONTINUE OVER THE
EASTERN MOUNTAINS AND PLAINS...THOUGH WITH FORCING STAYING RATHER
WEAK...SUSPECT CONVECTIVE COVERAGE WILL BE ONLY ISOLATED BOTH
DAYS. AFTER SOME MODEST COOLING ON MON...TEMPS BEGIN TO SLOWLY
CREEP BACK TO ABOVE SEASONAL LEVELS BY WED...ESPECIALLY OVER THE
PLAINS WERE A FEW 90S WILL REAPPEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1112 PM MDT WED AUG 27 2014
THUNDERSTORMS HAVE PULLED OFF TO THE NORTHEAST OF THE KCOS AND
KPUB TERMINALS AND CURRENT TRENDS SUGGEST THAT IT WILL REMAIN DRY
WITH VFR CONDITIONS FOR THE REMAINDER OF THE NIGHT. WINDS WILL
REMAIN LIGHT AT KALS OVERNIGHT...WHILE KCOS AND KPUB CONTINUE TO
SEE SOME BREEZY NORTH WINDS GUSTING TO 25 KTS THROUGH 08-09Z.
ANOTHER ROUND OF ENERGY FROM THE UPPER LEVEL SYSTEM WILL MOVE
ACROSS THE AREA THURSDAY MORNING. THIS MAY RESULT IN AN EARLY
START TO -SHRA/-TSRA ON THURSDAY...WITH SHOWERS POSSIBLE IN THE
VCNTY OF KCOS BY 16Z. STRONGER THUNDERSTORMS WILL HOLD OFF UNTIL
AFTER 18Z. NORTH WINDS WILL INCREASE OFF THE PALMER DIVIDE
DURING THE LATE MORNING THROUGH EARLY AFTERNOON FOR KCOS AND KPUB
WITH ISOLATED INSTABILITY -TSRA MOVING SOUTHWARD ACROSS THE PLAINS
DURING THE AFTERNOON. BRIEF HEAVY RAIN WITH MAINLY VFR CIGS CAN BE
EXPECTED WITH THE STRONGER CELLS. KALS WILL ALSO SEE A CHANCE FOR
VCTS DURING THE AFTERNOON...THOUGH WINDS WILL REMAIN LIGHTER. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HODANISH
LONG TERM...PETERSEN
AVIATION...KT
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1207 AM CDT THU AUG 28 2014
.UPDATE...
ISSUED AT 939 PM CDT WED AUG 27 2014
NO CHANGES TO EXISTING FLASH FLOOD WATCH HEADLINE. CURRENT NE/KS
MCS UPSTREAM IS EMBEDDED WITHIN A BROAD AREA OF WEAK/MODERATE
KINEMATIC AND THERMODYNAMIC FORCING AHEAD OF ROCKIES LONG WAVE
TROUGH IN AIRMASS VERY FAVORABLE FOR HEAVY EFFICIENT RAINFALL.
STRONGEST CONVECTION COINCIDES NICELY WITH 01Z RAP PRECIP
POTENTIAL PLACEMENT MAX AND THIS CROSSES MO RIVER INTO WRN
FORECAST AREA 09-12Z WITH MEAN WIND...THUS SLOWED POP ADVANCEMENT
SOMEWHAT IN EVENING UPDATE. 1-2KM MOISTURE FLOW AND ASSOCIATED
TRANSPORT IS NOT OVERLY STRONG...BUT VEERS INTO WRN IA BY
DAYBREAK. WITH PWS STILL IN EXCESS OF 2 INCHES...K INDICES AROUND
40...AND WARM CLOUD DEPTHS 4.2KM...ANY STRONGER CONVECTION COULD
CERTAINLY STILL PRODUCE EXCESSIVE RAINS.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 345 PM CDT WED AUG 27 2014
TIMING AND LOCATION OF HEAVY RAIN WAS FORECAST CONCERN TONIGHT
WITH ANOTHER ROUND OF CONVECTION ANTICIPATED TO DEVELOP OVERNIGHT.
LEANED TOWARD A BLEND OF THE ECMWF/NAM12 AND THE LATEST HRRR/HOPWRF/4.0KM
SPCWRF FOR TIMING OF THE PRECIP. BIGGEST CHANGE WAS SLOWED DOWN
THE ONSET ROUGHLY 2 TO 4 HOURS FROM PREVIOUS FORECAST PACKAGE AND
STILL MAY BE TOO QUICK FOR REDEVELOP TONIGHT.
LLJ INCREASES OVER SOUTH-CENTRAL NEBRASKA/NORTHERN KANSAS WITH THE
NOSE NUDGING INTO SOUTHWEST TO WESTERN PORTIONS OF THE IOWA PAST 06Z
THURSDAY. THE BEST THETA-E ADVECTION SURGES ACROSS SOUTHWEST IOWA
NORTHEASTWARD INTO NORTH-CENTRAL IOWA BY THURSDAY MORNING AND THE
BEST MOISTURE CONVERGENCE LOOKS TO BE B/T HIGHWAY 20 TO NEAR I-80
CORRIDORS BUT CERTAINLY NOT LIMITED TO THOSE LOCATIONS. PRECIPITABLE
WATER VALUES IN THE 2 TO 2.25 INCH RANGE OVER WESTERN IOWA AND WARM
LAYER CLOUD DEPTHS AROUND 13KFT...SO ANTICIPATING SOME EFFICIENT
RAIN PRODUCERS OVERNIGHT. MOISTURE TRANSPORT ERUPTS WITH THE LLJ
INCREASING OVERNIGHT AND WITH WEAK CORFIDI VECTORS...SUGGESTING
TRAINING POTENTIAL AS WELL. LEANED TOWARD ISSUING A FLASH FLOOD
WATCH BASED ON THE LATEST HIRES MODEL TRENDS AND 27.12Z NAM/ECMWF
CONVECTIVE/QPF TRENDS. IT WILL NOT TAKE MUCH TO GET SOME FLASH FLOOD
ISSUES OVER THE WESTERN PORTIONS OF THE FORECAST BY EARLY THURSDAY
MORNING. MAY NEED TO EXTEND/EXPAND THE WATCH FURTHER NORTH...BUT FFG
IS A BIT HIGHER ALONG THE MINNESOTA AND HAD LESSER CONFIDENCE WITH
FLASH FLOOD POTENTIAL IN THIS AREA.
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 345 PM CDT WED AUG 27 2014
MAIN CONCERNS WILL BE RAINFALL AND THREAT FOR ANY FLOODING THROUGH
THE EXTENDED PERIOD. ONGOING CONVECTION SHOULD BE DIMINISHING
THROUGH THE DAY...BUT MODERATE RAINFALL IS STILL EXPECTED AS THE
BOUNDARY LIFTS TO THE NORTHEAST AND MCS FOLLOWS AND LIFTS INTO
SOUTHERN MN. MODELS ARE NOW SPLIT ON LOCATION OF HEAVIER RAINFALL
THROUGH TOMORROW...BUT CONSENSUS IS FOR A SLIGHTLY SLOWER EVOLUTION
AND FARTHER SOUTH AND WEST MAX OVERALL...WHICH PUTS THE RAINFALL FOR
THURSDAY OVER NORTHERN IOWA A BIT LONGER INTO THE MORNING AND EARLY
AFTERNOON HOURS PRIOR TO CHANCES DIMINISHING DURING THE AFTERNOON.
EURO/GFS HAVE COME INTO LINE FARTHER SOUTH WITH TODAYS 12Z PACKAGE.
ISENTROPIC LIFT AND MOISTURE TRANSPORT FOCUSING BEST LIFT OVER
WEST CENTRAL/NORTHWEST IOWA TO START THE PERIOD AT 12Z THURSDAY
AND GRADUALLY SHIFTING THE BEST LIFT TOWARD THE IA/MN BORDER BY
18Z. SOMEWHAT COMPLICATED SCENARIO BOTH TONIGHT AND THURSDAY AS
UPPER LEVEL RIDGE AXIS HOLDING STRONG...AND EFFECTIVELY WILL
CREATE A STRONGER BOUNDARY ALOFT AS STRONG PUSH OF THETAE ADVECTION
ADVANCES NORTH...THEN HITTING A SLOWLY RETREATING RIDGE AXIS. THIS
IS PART OF THE REASON FOR THE MORE SOUTHERN FOCUS AS MASS CONVERGENCE
INCREASES OVERNIGHT/THURSDAY MORNING ACROSS THE NORTH. ONCE THE
MAIN FORCING LIFTS NORTHEAST WITH THE FIRST STRONG PUSH OF WARM
AIR...TWO MORE WEAK WAVES WILL LIFT NORTHEAST INTO THE AFTERNOON
AND OVERNIGHT HOURS WITH ADDITIONAL LIGHT TO MODERATE RAINFALL
EXPECTED THROUGH FRIDAY NIGHT. THE HIGHEST RAINFALL TOTALS WILL
OCCUR THROUGH THURSDAY...BUT ANY ADDITIONAL RAINFALL WILL ADD TO
THE POTENTIAL FOR A RISK OF SOME FLOODING...EITHER RIVER OR
ISOLATED FLASH FLOODING. WILL BE MONITORING CLOSELY OVER THE NEXT
COUPLE OF DAYS AFTER TONIGHTS EVENT UNFOLDS. WITH CLOUDS AND
RAINFALL EXPECTED...HIGHS WILL BE HELD BACK TO NEAR 70 NORTH TO
THE LOWER 80S ACROSS THE SOUTH. RAIN CHANCES REMAIN HIGH THROUGH
FRIDAY NIGHT WITH A MUCH NEEDED BREAK ARRIVING FOR MOST OF
SATURDAY AND A PART OF SUNDAY. MODELS DIFFER ON DETAILS AGAIN BY
SUNDAY...WITH EURO BEING SLIGHTLY SLOWER IN ARRIVAL OF RATHER
ROBUST LATE SUMMER SYSTEM. ANOTHER PERIOD OF MODERATE TO POSSIBLY
HEAVY RAIN COULD OCCUR SUNDAY EVENING WITH THE PASSAGE OF THE NEXT
SYSTEM. ADDITIONALLY...ALONG WITH A SHORT WAVE ARRIVING IN THE
EARLY EVENING...UPPER LEVEL WIND FIELDS AND INSTABILITY INCREASE
ENOUGH TO BE CONCERNED WITH MORE ORGANIZED SEVERE WEATHER LATE
SUNDAY AFTERNOON AND EVENING. THE MORE PROGRESSIVE NATURE OF THE
SYSTEM SHOULD RESULT IN A QUICKER EXIT...WITH A RETURN TO DRIER
WEATHER FOR TUESDAY AND WEDNESDAY. FOR NOW WILL TREND POPS DOWN ON
TUESDAY...WITH A CHANCE WE COULD BE TOTALLY DRY BY THAT TIME.
HIGHS THROUGH MOST OF THE PERIOD WILL BE IN THE 70S TO LOWER 80S.
&&
.AVIATION...28/06Z
ISSUED AT 1207 AM CDT THU AUG 28 2014
LITTLE CHANGE FROM PREVIOUS THINKING /00Z/ WITH PRIMARY CONCERN CATEGORY
CHANGES DRIVEN BY EXPANDING CONVECTION OVERNIGHT. ALTHOUGH MVFR
CIGS HAVE EXPANDED SOMEWHAT THEY HAVE YET TO REACH TAF SITES WHICH
REMAIN VFR AT 06Z. EXPECT CIGS AND VSBYS TO LOWER TO MVFR AND
POSSIBLY IFR WITH PRECIP ONSET BY EARLY THIS MORNING AS IT CROSSES
THE MO RIVER INTO IA...AND COULD LAST FOR A PROLONGED PERIOD.
CONDITIONS MAY RETURN TO VFR BY THU AFTERNOON...BUT POTENTIAL FOR
AT LEAST LIGHT PRECIP WILL LINGER THROUGH THE ENTIRE PERIOD. NRN
SITES /KMCW/ MAY ALSO EXPERIENCE A RETURN TO LOWER CIGS/VSBYS
DURING THE EVENING.
&&
.HYDROLOGY...
ISSUED AT 345 PM CDT WED AUG 27 2014
RAINFALL RATES OF 1 TO 2 INCHES PER HOUR WITH LOCALLY HIGHER
RATES ARE POSSIBLE OVER WEST-CENTRAL TO SOUTHWEST IOWA LATE
TONIGHT INTO THURSDAY. 1-HR FFG IS AROUND AN INCH AND 3-HR FFG IS
LESS THAN 2 INCHES IN MOST PLACES...SO GROUND IS PRIMED FOR FLASH
FLOODING OVERNIGHT. WITH THE WIDESPREAD QPF AMOUNTS OF 1 TO 2
INCHES FROM 09Z THURSDAY TO 00Z FRIDAY...THE RACCOON AND SMALLER
RIVER BASINS MAY SEE RISES BY THURSDAY INTO FRIDAY AND ATTM MAINLY
REACHING ACTION STAGE OR MINOR FLOOD STAGE.
HYDROLOGY CONCERNS REMAIN ACROSS THE AREA THROUGH MONDAY. WITH
ADDITIONAL RAIN EXPECTED THURSDAY NIGHT THROUGH EARLY SATURDAY
MORNING...AND ANOTHER ROUND OF POSSIBLE MODERATE TO HEAVY RAINFALL
OVER PORTIONS OF THE AREA SUNDAY AFTERNOON/EVENING...ADDITIONAL
SMALLER STREAM AND RIVER RESPONSES ARE LIKELY. ITS TOO EARLY TO
GAUGE THE OVERALL MAGNITUDE OF THE IMPACTS...WITH RIVER LEVELS
CURRENTLY RUNNING WELL BELOW FLOOD STAGE AT MOST LOCATIONS. AFTER
TOMORROW...THERE WILL BE BETTER CLARIFICATION ON THE IMPACTS
EXPECTED OVER THE WEEKEND.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 3 AM CDT EARLY THIS MORNING THROUGH THIS
MORNING FOR ADAIR-ADAMS-AUDUBON-CALHOUN-CARROLL-CASS-CLARKE-
CRAWFORD-DALLAS-DECATUR-GREENE-GUTHRIE-MADISON-RINGGOLD-SAC-
TAYLOR-UNION.
&&
$$
UPDATE...SMALL
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...SMALL
HYDROLOGY...PODRAZIK/REV
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
346 AM CDT THU AUG 28 2014
.SHORT TERM...
NOT MUCH ON RADAR TO START OFF THE MORNING OTHER THAN A FEW SHOWERS
OFFSHORE. RAIN CHANCES WILL BE SIMILAR TO YESTERDAY FOR MOST
PORTIONS OF THE CWA EXPECT FOR LA COASTAL PARISHES WHERE POPS SHOULD
ONLY BE AROUND 30 PCT RATHER THAN 50S. THIS IS THE RESULT OF SURFACE
LOW IN THE WESTERN GULF CONTINUING TO TRACK FURTHER AWAY FROM THE
ARE. THE FCST IS IN THE MIDDLE BETWEEN THE GENERAL HRRR AND MODEST
GFS/ECMWF. EXPECTING HIGHER POPS TO BE IN THE WESTERN HALF OF THE
FORECAST AREA. MS COUNTIES MAY NOT SEE ANY CONVECTION.
.LONG TERM...
AN UPPER LEVEL TROUGH MOVING EAST ACROSS THE CENTER OF THE ROCKY
MOUNTAINS THIS MORNING IS SPLITTING AN UPPER RIDGE THATS STRUGGLING
TO MAINTAIN ITSELF OVER THE SOUTHERN HALF OF THE COUNTRY AT THIS
TIME. BY DOING SO...THE GULF OF MEXICO WILL BE OPENED UP TO THE AREA
THROUGH THE WEEKEND WHICH WILL SET THE STAGE FOR EVEN HIGHER RAIN
CHANCES FRIDAY THROUGH SUNDAY. IMPULSES RIDING AROUND THE HIGH
CENTERED TO THE EAST WILL PASS OVER THE CWA THROUGH THIS PERIOD
WHICH WILL ENHANCE SHOWER AND THUNDERSTORM DEVELOPMENT. MODEL
SOUNDINGS SHOW ABUNDANT MOISTURE WILL BE IN PLACE WITH PRECIPITABLE
WATER VALUES ON THE ORDER OF 2 TO 2.25 INCHES. THUS THINKING
COVERAGE WILL BE FAIRLY WIDESPREAD AND RAINFALL RATES QUITE HEAVY.
HAVE INCREASED POPS ON SATURDAY TO 70 PERCENT AND THAT MAY NOT BE
HIGH ENOUGH. LOCALIZED FLOODING WILL LIKELY BE AN ISSUE IN SOME
AREAS. INCREASED CLOUD COVER AND WIDESPREAD CONVECTION SHOULD LIMIT
DAILY WARMING...SO HAVE KEPT HIGHS SLIGHTLY BELOW NORMAL.
RAIN CHANCES SHOULD START TO COME BACK DOWN STARTING NEXT WEEK AS
THE TROUGH TO THE NORTH FINALLY LIFTS AND UPPER RIDGE BUILDS BACK IN
ACROSS THE SOUTH. GFS AND ECMWF ARE SHOWING A TROPICAL WAVE MOVING
ACROSS THE YUCATAN PENINSULA GOING INTO THE MIDDLE OF NEXT WEEK. IT
REMAINS TO BE SEEN IF THIS SOLUTION MATERIALIZES. STILL WAY TOO FAR
OUT TO HAVE ANY CONCERN AT THIS POINT.
MEFFER
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL AT ALL OF THE TERMINALS THROUGH THE
FORECAST PERIOD WITH A SCATTERED TO BROKEN CU FIELD RUNNING AROUND
4-5K FEET. THERE MAY BE SOME LIGHT FOG DEVELOPMENT AROUND 10-12Z
THIS MORNING AT KASD...KHDC...AND KMCB WHICH COULD REDUCE
VISIBILITIES TO AROUND 4-5 MILES. ANY FOG SHOULD QUICKLY CLEAR AFTER
13Z...AS DAYTIME HEATING MIXES OUT THE BOUNDARY LAYER. SOME
SCATTERED CONVECTION MAY ALSO IMPACT KHUM BETWEEN 17Z AND 23Z. HAVE
INCLUDED VCTS WORDING TO REFLECT THIS RISK. 32
&&
.MARINE...
EAST-SOUTHEAST FLOW OF 10 TO 15 KNOTS AND SEAS OF 2 TO 4 FEET CAN BE
EXPECTED TODAY AS AN INVERTED TROUGH EXTENDING ACROSS THE WESTERN
GULF OF MEXICO SLOWLY MOVES INTO TEXAS. THIS INITIAL TROUGH WILL
MOVE INTO TEXAS TONIGHT...BUT ANOTHER INVERTED TROUGH AXIS WILL MOVE
NORTH INTO THE COASTAL WATERS TOMORROW. THIS TROUGH WILL KEEP
SOUTHEAST FLOW OF 10 TO 15 KNOTS IN PLACE THROUGH SATURDAY. SEAS
WILL INCREASE INTO THE 3 TO 5 FEET RANGE IN THE OFFSHORE WATERS AS A
1 TO 2 FOOT SWELL TRAIN DEVELOPS IN THE GULF. RIDGING WILL BUILD
WESTWARD FROM THE EASTERN GULF FOR THE LATTER HALF OF THE
WEEKEND...KEEPING SOUTHEAST FLOW OF 10 TO 15 KNOTS IN PLACE. THESE
CONDITIONS WILL PERSIST INTO TUESDAY. 32
&&
.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT..
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 91 71 92 74 / 20 10 30 30
BTR 93 74 92 76 / 30 20 40 40
ASD 92 74 91 78 / 30 20 50 40
MSY 90 78 90 78 / 30 20 50 40
GPT 91 75 90 79 / 20 10 50 40
PQL 91 73 90 78 / 20 10 40 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1145 PM CDT WED AUG 27 2014
.UPDATE...
ISSUED AT 1140 PM CDT WED AUG 27 2014
NO CHANGE FROM THE PREVIOUS UPDATE.
UPDATE ISSUED AT 954 PM CDT WED AUG 27 2014
SOME POP CHANGES FROM NEIGHBORING OFFICES THIS EVENING...MAINLY TO
SLOW DOWN ADVANCE OF PRECIP CHANCES NORTHWARD INTO SE ND/WCNTRL
MN. WENT ALONG WITH CHANGES. AGREES WITH RADAR AND LATEST HRRR AS
WELL. MID LEVEL MOISTURE SPREADING EAST-NORTHEAST THRU SE ND AS
EXPECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 305 PM CDT WED AUG 27 2014
NEXT CHANCE OF LIGHT RAIN WHICH ARRIVES LATER TONIGHT REMAINS THE
MAIN FORECAST CHALLENGE. MODELS HAVE BEEN BACK AND FORTH WITH THIS
FEATURE THE LAST COUPLE OF DAYS...ONE RUN PUSHING IT SOUTH OF THE
FA WHILE THE NEXT KEEPS IT THERE. TODAYS RUNS DO NOT ADD MUCH
CONFIDENCE TO THE RAIN FORECAST ACROSS THE SOUTH...SO WILL
GENERALLY STICK TO FORECAST CONTINUITY FOR NOW (WHICH KEEPS IT
IN). AS FOR LATE THIS AFTERNOON THE CUMULUS HAS BEEN THICKEST
ACROSS THE SOUTH WHILE IT HAS BEEN FADING OUT IN THE NORTH. LOOKS
LIKE THIS TREND WILL CONTINUE TONIGHT WHICH WILL RESULT IN WARMER
MIN TEMPS ACROSS THE SOUTH. THERE HAS BEEN FOG THE LAST COUPLE OF
NIGHTS...BUT ARE EXPECTING INCREASING CLOUDS ACROSS THE SOUTH. IF
ANY FOG FORMS TONIGHT IT MAY BE ACROSS THE NORTH. NOT SURE EXACTLY
WHEN ANY LIGHT SHOWERS WILL BREAK OUT ACROSS THE SOUTH AS EVEN THE
HIGH RESOLUTION MODELS DIFFER...SO WILL STICK WITH ITS ARRIVAL
COMING AFTER MIDNIGHT AND MAINLY ALONG AND SOUTH OF INTERSTATE 94.
12Z GFS IS THE MOST ROBUST AND FURTHEST NORTH WITH THE PCPN WHILE
OTHER MODELS ARE MUCH WEAKER...SO WILL GIVE THE LEAST WEIGHT TO
ITS SOLUTION. HOWEVER WILL EXPAND PCPN CHANCES A LITTLE FURTHER
NORTH FOR THURSDAY. WITH MORE CLOUDS/PCPN ACROSS THE SOUTH...HIGH
TEMPS WILL BE A LITTLE COOLER THERE. NEXT FRONTAL BOUNDARY WILL
ARRIVE LATE THU NIGHT IN THE NORTH BRINGING THE NEXT CHANCE FOR
PCPN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED AUG 27 2014
THE ABOVE MENTIONED FRONT WILL CONTINUE TO SLIDE SOUTH AND EAST ON
FRIDAY WITH PCPN CHANCES ALONG IT. HIGH PRESSURE SLIDES INTO THE
REGION LATER FRIDAY INTO SATURDAY ENDING ANY LINGERING PCPN
CHANCES.
FOR SAT NIGHT THROUGH WED...THE PERIOD SHOULD START OUT QUIET
ACTIVE...WITH MODELS IN GOOD AGREEMENT. A STRONG UPPER WAVE AND
FRONTAL BOUNDARY WILL MOVE THROUGH LATER SAT NIGHT THROUGH SUNDAY.
PWATS WILL RISE OVER 1.5 INCHES...WITH MLCAPES RISING OVER 1500 J/KG
IN THE EAST SUNDAY. WE EXPECT A ROUND OF SHOWERS AND STORMS WITH
ELEVATED CONVECTION SAT NIGHT INTO EARLY SUNDAY. MORE VIGOROUS SFC
BASED STORMS AND POSSIBLE STRONG/SEVERE STORMS ARE POSSIBLE
SUNDAY...DEPENDING ON TIMING OF WAVE AND FRONT. IT SHOULD BE MAINLY
DRY BY MONDAY THROUGH WED...WITH TEMPS NEAR NORMAL FOR EARLY
SEPTEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1140 PM CDT WED AUG 27 2014
LITTLE CHANGE WITH THE 06Z TAFS. OF CONCERN IS AN AREA OF MVFR
CIGS IN THE BISMARCK AREA THAT THE HRRR WANTS TO BRING A BIT NORTH
TOWARD DEVILS LAKE BY 11Z. DID ADD A TEMPO GROUP FOR MVFR CIGS AT
DVL FOR THIS DURING THE MORNING. OTHERWISE EXPECT THE 5-6K FT CIGS
TO SPREAD NORTHEAST GRADUALLY OVERNIGHT AND HANG AROUND MOST AREAS
THRU THURSDAY. DID NOT INCLUDE SHOWERS AT FARGO AS COVERAGE AND
TIMING VERY QUESTIONABLE AS BEST CHANCE REMAINS SOUTH OF FARGO.
WINDS MAINLY SOUTHERLY 8 TO 15 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/DK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
143 AM EDT THU AUG 28 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SOUTH INTO THE REGION TONIGHT AND
STALL ACROSS OUR AREA THROUGH THURSDAY AND FRIDAY...PROVIDING THE
FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS. THE FRONT WILL
LIFT NORTH AGAIN FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 945 PM EDT WEDNESDAY...
WATCHING A BROKEN LINE OF THUNDERSTORMS APPROACHING FROM THE
NORTHWEST. HRRR 23Z RUN SHOWS SOME OF THIS ACTIVITY REACHING
WESTERN GREENBRIER COUNTY. ADDED SLIGHT CHANCE TO CHANCE POPS FOR
THE NEXT FEW HOURS ALONG WITH ADDING THUNDER TO THE GRIDS. BUMPED
UP CLOUD COVER ACROSS THIS AREA AS WELL.
AS OF 225 PM EDT WEDNESDAY...
NOT SEEING MUCH IN THE WAY OF SHRA DEVELOPMENT THIS AFTERNOON.
BEST CU FIELD LIES FROM THE MTNS OF GREENBRIER COUNTY NEWD ALONG
THE ALLEGHANY FRONT. INSTABILITY IS MARGINAL WITH BEST SITUATED
ACROSS KY INTO OHIO AND PA. WILL KEEP ISOLATED THREAT OF SHRA/TSRA
THIS EVENING ACROSS THE WRN FRINGES OF SE WV/FAR SW VA AND BATH
VA. MAINLY LOOKING AT CLEAR SKIES ELSEWHERE BUT MOISTURE IS
STARTING TO INCREASE AS NOTED BY DEWPOINTS ASCENDING INTO THE 60S.
LOW TEMPS AS SUCH ARE GOING TO BE MILDER THAN PREVIOUS SEVERAL
NIGHTS WITH LOWS IN THE MID TO UPPER 50S MOUNTAIN VALLEYS TO MID 60S
PIEDMONT.
BACKDOOR FRONT WILL SHIFT ACROSS THE VA/NC BORDER LATE TONIGHT/THU
MORNING. MODELS SHOW AXIS OF CONVERGENCE TO ALIGN ACROSS THE NC MTNS
INTO THE PIEDMONT OF VA TOMORROW AFTERNOON AND THIS WILL BE WHERE
TSRA WILL FORM...BUT COVERAGE WILL BE SCATTERED AT BEST...SO KEPT
POPS IN THE 20/30 RANGE. MAINLY DRY NORTH OF A BLF-ROA LINE.
CLOUDS WILL BE SCATTERED/BKN AFTER ANY MORNING FOG LIFTS...WITH
HIGHS SURGING INTO THE 80S MOST AREAS WITH LOWER 90S SOUTHEAST.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 330 PM EDT WEDNESDAY...
MODELS ARE IN GOOD AGREEMENT THAT A WEAK FRONT WILL BE STALLED
ACROSS NORTHERN NORTH CAROLINA THURSDAY NIGHT AND FRIDAY...PROVIDING
THE FOCUS FOR SHOWER ACTIVITY...POSSIBLY WITH A FEW THUNDERSTORMS
DEVELOPING FRIDAY AFTERNOON/EVENING WITH DAYTIME HEATING. CANNOT
IDENTIFY WITHIN THE MODEL DATA ANY STRONG DISTURBANCES RIDING ALONG
THE FRONT...SO BELIEVE THE RAINFALL WILL BE OF THE LIGHT AND
OCCASIONAL VARIETY.
LOW PRESSURE PASSING ACROSS THE GREAT LAKES WILL DRAW THE FRONTAL
BOUNDARY BACK TO THE NORTH AS A WARM FRONT FRIDAY NIGHT...WITH WEAK
HIGH PRESSURE BUILDING BACK ACROSS OUR AREA ON SATURDAY FROM THE
CAROLINAS. CANNOT RULE OUT A FEW SHOWERS OR STORMS DEVELOPING ACROSS
THE MOUNTAINS DURING SATURDAY AFTERNOON AND EVENING...BUT THE DIP IN
ATMOSPHERIC MOISTURE ASSOCIATED WITH THE HIGH WILL KEEP THIS
ACTIVITY RATHER ISOLATED.
SATURDAY NIGHT...SOUTHWESTERLY FLOW WILL BECOME FIRMLY REESTABLISHED
AS UPPER LEVEL RIDGING RESIDES ACROSS THE SOUTHEAST STATES...WHILE
AN UPPER LEVEL TROUGH MOVES TOWARDS THE GREAT LAKES. AS SUCH...
EXPECT ATMOSPHERIC MOISTURE TO RAMP UP OVERNIGHT THANKS TO A DIRECT
WINDS OFF THE GULF OF MEXICO. CLOUD COVER WILL INCREASE AFTER
SUNSET...WITH A FEW SHOWERS ENTERING THE MOUNTAINS TOWARD SUNRISE
SUNDAY.
TEMPERATURES THROUGH THE PERIOD WILL BE CLOSER TO NORMAL FOR LATE
AUGUST THANKS TO INCREASED CLOUD COVER/MOISTURE POOLING ALONG THE
FRONT. LOOK FOR HIGHS TO REACH INTO THE 80S MOST LOCATIONS FRIDAY
AND SATURDAY...WHILE OVERNIGHT LOWS WILL BE MILDER THAN PREVIOUS
NIGHTS...GENERALLY HOLDING IN THE 60S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 PM EDT WEDNESDAY...
DEEP GULF MOISTURE FLOWING NORTH ALONG THE APPALACHIAN CHAIN WILL
MAINTAIN A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY FOR THE
EARLY HALF OF NEXT WEEK.
FOR SUNDAY...RAINFALL IS LOOKING INCREASINGLY LIKELY AS AN
UPPER LEVEL TROUGH MOVES UP THE OHIO RIVER VALLEY. WITH
PERCEPTIBLE WATER VALUES IN THE BALLPARK OF 2 INCHES ACROSS OUR
AREA...BELIEVE THAT LOCALLY EXCESSIVE RAINFALL WILL BE POSSIBLE IN
SOME AREAS... ESPECIALLY IF STORMS BEGIN TO PASS REPEATEDLY OVER
THE SAME LOCATIONS.
ON MONDAY...UPPER LEVEL FLOW BEGINS TO TRANSITION TO A MORE WEST TO
EAST ORIENTATION...WITH NO STRONG DISTURBANCES EXPECTED. BELIEVE
SHOWER AND THUNDERSTORM ACTIVITY WILL BE MORE DRIVEN BY DAYTIME
HEATING THAN ANYTHING ELSE...MEANING RAINFALL WILL BE MORE OF THE
HIT AND MISS VARIETY.
LOOKING TO TUESDAY...EXPECT A SLIGHTLY BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS AS A COLD FRONT APPROACHES OUR REGION FROM THE
NORTHWEST. BEST CHANCES FOR SHOWER AND THUNDERSTORM ACTIVITY WILL BE
DURING THE EVENING AS THE FRONT APPROACHES THE OHIO RIVER...HOWEVER
WITH NO REAL PUSH OF COLD AIR BEHIND THE FRONT...IT IS ENTIRELY
POSSIBLE THAT THE OHIO RIVER IS AS FAR SOUTH AS THE FRONT SINKS.
ABUNDANT GULF MOISTURE WILL MAKE FOR MUGGY AND WARM CONDITIONS FOR
THE EARLY HALF OF NEXT WEEK. LOOK FOR HIGHS TO RANGE FROM THE UPPER
70S/LOW 80S ACROSS THE MOUNTAINS...TO THE UPPER 80S ACROSS THE
PIEDMONT. OVERNIGHT LOWS WILL RANGE FROM THE MID 60S TO LOW 70S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 135 AM EDT THURSDAY...
CLUSTER OF SHOWERS AND THUNDERSTORMS WAS MOVING SOUTH THROUGH
WEST VIRGINIA...JUST TO THE WEST OF THE KLWB AND KBLF AIRPORT.
EXPECT PRECIPITATION TO WEAKEN AS IT CONTINUES TO MOVE SOUTH.
AMOUNT OF FOG EARLY THIS MORNING WILL DEPEND ON THE CLOUD COVER
MOVING THROUGH THE AREA. HAVE DELAYED THE TIMING ON LIFR FOG AT
KLWB. LOWER CONFIDENCE OF FORMATION OF IFR OR LIFR FOG AT KBCB
WITH THE MID LEVEL CLOUDS APPROACHING.
WEAK SURFACE COLD FRONT WILL CROSS THE FORECAST AREA EARLY
TODAY...THEN BECOME STATIONARY ACROSS NORTH CAROLINA TONIGHT.
CONVERGENCE ALONG THE FRONT WILL PERMIT SCATTERED SHRA/TSRA AGAIN
THIS AFTERNOON. POSITION OF FRONT BY THAT TIME SUGGESTS SHRA/TSRA
ACTIVITY WILL DEVELOP VCNTY OF THE VA/NC BORDER...THEN DRIFT
SOUTHEAST INTO NORTH CAROLINA WITH THE MEAN WIND WHICH WILL BE OUT
OF THE NORTHWEST. FOR NOW HAVE LEFT ANY SHOWERS AND THUNDERSTORMS
OUT OF THE KDAN TAF.
EXTENDED DISCUSSION...
THE WEAK FRONT IS FORECAST TO RETURN NORTH AS A WARM FRONT
SATURDAY. WIDELY SCATTERED SHRA/TSRA ARE EXPECTED ALONG THIS
BOUNDARY FRIDAY AND SATURDAY...WITH THE GREATEST COVERAGE DURING
THE PEAK HEATING OF THE DAY. WHERE SHRA/TSRA OCCUR BRIEF PERIOD OF
SUB VFR CONDITIONS CAN BE EXPECTED.
AN AREA OF LOW PRESSURE IS FORECAST TO MOVE THROUGH THE GREAT
LAKES SATURDAY NIGHT AND SUNDAY...THE ASSOCIATED COLD FRONT
TRAILING SOUTH AND MOVING ACROSS THE OHIO/TN VALLEYS. SHOWERS AND
THUNDERSTORMS WILL LIKELY BE ASSOCIATED WITH THIS FRONT...THIS
ACTIVITY SPREADING EAST INTO THE CENTRAL APPALACHIANS SUNDAY AND
MONDAY. SHOWER COVERAGE SUNDAY/MONDAY IS EXPECTED TO BE MUCH MORE
WIDESPREAD AS COMPARED TO FRIDAY AND SATURDAY.
&&
.EQUIPMENT...
AS OF 1130 AM EDT WEDNESDAY ...
THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL
AIRPORT...REMAINS OUT OF SERVICE. A PART HAS BEEN ORDERED BUT
APPEARS REPAIRS WILL NOT BE DONE UNTIL THIS FRIDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...CF/WP
SHORT TERM...NF
LONG TERM...NF
AVIATION...AMS/PM
EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 PM CDT WED AUG 27 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 328 PM CDT WED AUG 27 2014
FORECAST FOCUS IS ON PRECIPITATION TIMING AND AMOUNTS...THREAT
FOR HEAVY RAIN WITH LOCALIZED FLOODING.
AS OF MID AFTERNOON...WATER VAPOR IMAGERY OVERLAID WITH RAP 500
MB HEIGHTS SHOWED DECAYING DISTURBANCE ACROSS IOWA...WITH MAIN
CLOSED LOW ROTATING INTO NORTHWESTERN COLORADO. WEAK IMPULSES WERE
RIDING THE PERIPHERY OF THE TROUGH...AND IT IS THESE IMPULSES THAT
WILL BE THE PLAYERS FOR THE NEXT 24 TO 48 HOURS ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY.
AT THE SURFACE...LINGERING SHOWERS AND THUNDERSTORMS HAVE BEEN
CONFINED TO SOUTHERN AND SOUTHWESTERN IOWA...KEEPING FRONTAL
BOUNDARY ACROSS SOUTHERN IOWA / NORTHERN MISSOURI. THE 65F
DEWPOINT LINE IS GENERALLY SOUTH OF I-80.
THE LARGEST CHANGES TO ONGOING FORECAST HAVE BEEN RELATED TO
PRECIPITATION TIMING...AS 27.12Z MODEL CYCLES TREND TOWARD A LATER
ARRIVAL OF THE GREATEST 850MB MOISTURE TRANSPORT OVERNIGHT THROUGH
THE DAY ON THURSDAY. MOST OF THE DETERMINISTIC AND HI-RES MODELS
SHOW A SHIELD OF RAIN SHOWERS WITH EMBEDDED THUNDERSTORMS REACHING
NORTHEAST IOWA / SOUTHEAST NOT UNTIL THE EARLY MORNING HOURS /4 TO
6 AM/ THEN MOVING INTO WESTERN WISCONSIN MID TO LATE MORNING.
PRECIPITATION CHANCES HAVE BEEN ADJUSTED...BUT OVERALL CONFIDENCE
REMAINS VERY HIGH SO KEPT 90 TO 100 CHANCES.
THE NOSE OF THE 850MB MOISTURE TRANSPORT LIFTS THROUGH THE AREA
DURING THE DAY...SO ANY COMPLEX OF SHOWERS/STORMS WILL LIKELY BE
PROGRESSIVE. HOWEVER...THE ATMOSPHERE WILL INCREASINGLY BECOME
MORE FAVORABLE FOR HEAVY RAINFALL RATES...AS PWATS APPROACH 2
INCHES. WARM CLOUD DEPTHS EXCEED 4 KM ACROSS MUCH OF THE AREA. THE
STORM TOP WINDS ARE PROGGED TO BE 25 TO 30 KTS...WHICH SHOULD HELP
KEEP CONVECTION PROGRESSIVE ENOUGH. THOUGH WITH BROAD WARM AIR
ADVECTION AND ISENTROPIC LIFT DURING THE DAY...HAVE KEPT HIGH
PRECIPITATION CHANCES THROUGH THE EVENING HOURS. THE GREATER FOCUS
SEEMS TO BE ON WESTERN INTO NORTH CENTRAL WISCONSIN...THOUGH MOST
AREAS WILL SEE SHOWERS/STORMS THROUGHOUT THE DAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 328 PM CDT WED AUG 27 2014
THE MAIN 500MB SHORTWAVE BEGINS TO SWING THROUGH THE UPPER
MIDWEST FRIDAY EVENING INTO SATURDAY MORNING...WITH THE GREATEST
500-300MB PV ADVECTION ALIGNED FROM CENTRAL AND EASTERN IOWA INTO
SOUTHERN WISCONSIN. THE MOIST AIRMASS WILL LINGER THROUGH THIS
PERIOD AS WELL...AS THE OVERALL ENVIRONMENT SUPPORTS EFFICIENT
RAIN PRODUCES. THE SURFACE FRONT WILL LIKELY STALL FROM IOWA INTO
SOUTHERN WISCONSIN AND COULD BE THE FOCUS FOR SEVERAL EPISODES FOR
SHOWERS/STORMS. DEPENDING ON THE HEAVY RAINFALL OUTCOME IN ROUND
ONE...THIS PERIOD WILL NEED TO BE WATCHED FOR REPEATED ROUNDS.
THOUGH AT THIS POINT...IT LOOKS LIKE DIFFERENT AREAS WILL SEE THE
ROUNDS OF HEAVIER RAINFALL.
IT DOES LOOK LIKE BY SATURDAY MOST OF THE UPPER LEVEL ENERGY
MOVES EAST...AND THE PRECIPITATION CHANCES ARE CONFINED TO
SOUTHERN AND CENTRAL WISCONSIN. FOR THOSE PLANNING ACTIVITIES THIS
UPCOMING HOLIDAY WEEKEND...THE SATURDAY NIGHT TO SUNDAY MORNING
TIMEFRAME HAS THE GREATEST LIKELIHOOD TO SEE DRIER PERIODS.
SUNDAY THROUGH MONDAY WILL FEATURE AN APPROACHING UPPER LEVEL
SHORTWAVE FROM THE NORTHERN PLAINS. 27.12Z MODELS ALREADY SHOW
THIS FEATURE TO BE A BIT VIGOROUS AS IT SWINGS THROUGH. AT THE
SURFACE...THIS WILL DRIVE A COLD FRONT THROUGH THE UPPER MIDWEST.
THERE REMAINS SOME TIMING DIFFERENCES BETWEEN THE GFS/ECMWF/GEM
BUT THE TREND HAS BEEN FOR THE FRONTAL PASSAGE TO BE LATE SUNDAY
NIGHT OR EARLY MONDAY MORNING. SEVERE CHANCES LOOK LIMITED RIGHT
NOW GIVEN TIMING BUT 500 TO 1000 MUCAPE TRANSLATES AHEAD OF THE
FRONT WITH MARGINAL 0-6KM SHEAR VALUES /20 KTS/. SOMETHING TO KEEP
AN EYE WITH THE HOLIDAY WEEKEND...ESPECIALLY IF THE TIMING BECOMES
MORE FAVORABLE DURING PEAK HEATING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1136 PM CDT WED AUG 27 2014
28.00Z FORECAST GUIDANCE CONTINUED ON THE TREND OF SLOWING
NORTHEASTWARD PROGRESS OF SHOWERS AND THUNDERSTORMS...SO DELAYED
-SHRA ANOTHER HOUR OR TWO...IMPACTING KRST BY 28.15Z AND KLSE BY
28.17Z. SHOWERS (HEAVY AT TIMES) WILL DOMINATE...BUT STILL EXPECT
SOME EMBEDDED THUNDER...SO WILL KEEP AFTERNOON TEMPO GROUPS TO
HIGHLIGHT POTENTIAL THREAT. VFR CONDITIONS TO PERSIST OVERNIGHT
INTO THURSDAY MORNING...BUT MVFR CEILINGS/VISIBILITY EXPECTED
WITH HEAVIER SHOWERS AND THUNDERSTORMS LATER IN THE DAY. WINDS
THROUGH THE PERIOD WILL REMAIN LIGHT...GENERALLY VARIABLE OR FROM
THE SOUTHEAST.
&&
.HYDROLOGY...THURSDAY THROUGH FRIDAY NIGHT
ISSUED AT 328 PM CDT WED AUG 27 2014
VERY FAVORABLE SETUP FOR EFFICIENT...HEAVY RAIN PRODUCERS OVER
THE NEXT FEW DAYS. WARM CLOUD DEPTHS CONTINUE TO HOVER NEAR 4000 M
/IF NOT HIGHER/ WHILE PWATS PEAK AROUND 2 INCHES THURSDAY-
THURSDAY NIGHT. HEAVIER RAIN SIGNALS ARE PROGRESSIVE...THROUGH
NORTHERN IOWA INTO SOUTHEAST MINNESOTA AND THEN NORTH CENTRAL
WISCONSIN. FOR ROUND TWO...THE HIGHER THREAT LOOKS TO BE ACROSS
EASTERN IOWA INTO SOUTHERN WISCONSIN.
RUN TOTAL QPF FROM THE EC/GFS/GEM THROUGH SATURDAY RANGE FROM 2
TO 4 INCHES. LOCALLY HIGHER AMOUNTS ARE LIKELY. AT THIS
MOMENT...THINK THERE COULD BE QUICK RISES ON SOME RIVERS...BUT
SHOULD STAY WITHIN BANK. AS ALONG AS STORMS MOVE...AND AREAS DON/T
GET REPEATED HITS...THE FLASH FLOOD THREAT IS REDUCED. ALL
SAID...WITH THE HIGH LIKELIHOOD OF HEAVY RAIN...AND THE POTENTIAL
FOR SIGNIFICANT AMOUNTS...WILL MAINTAIN HYDROLOGIC OUTLOOK TO
HIGHLIGHT THE THREATS. A FLASH FLOOD WATCH MAY BE NECESSARY IF
SIGNALS ARE FOR THE ROUNDS OF HEAVY RAINFALL LOOK TO REPEAT OVER
THE SAME AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...ROGERS
HYDROLOGY....ZT/RIECK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
409 AM MDT THU AUG 28 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM MDT THU AUG 28 2014
CURRENT WATER VAPOR IMAGERY AND UPPER AIR ANALYSIS INDICATING A
BROAD UPPER TROUGH MOVING ACROSS THE ROCKIES...WITH A DISTINCT
CIRCULATION ACROSS NORTH CENTRAL COLORADO AT THIS TIME. WATER VAPOR
IMAGERY IS ALSO INDICATING THE MAIN MONSOONAL MOISTURE PLUME HAS
PUSHED EAST ACROSS THE SOUTHERN HIGH PLAINS AND INTO THE UPPER
MIDWEST...WITH CURRENT DRY SLOT ACROSS THE SE PLAINS DECREASING AS
EMBEDDED MOISTURE ASSOCIATED WITH THE TROUGH IS MOVING EAST.
TODAY...WILL SEE NORTHWEST FLOW ALOFT INCREASING THROUGH THE DAY AS
THE UPPER TROUGH AND MAIN VORT MAX CONTINUES TO LIFT NORTH AND EAST
INTO THE THE NORTHERN HIGH PLAINS. THE LATEST NAM AND GFS CONTINUE
TO INDICATE MORE WIDESPREAD PRECIPITATION ACROSS THE AREA AND HAVE
FOLLOWED THE HIGHER RESOLUTION NSSL WRF...HRRR AND RAP WHICH SEEM TO
HAVE PICKED UP ON FURTHER NORTH MOVEMENT OF THE SYSTEM AND ARE
KEEPING THE BEST CHANCES OF SHOWERS OVER AND NEAR THE NORTHERN AND
CENTRAL MTS WITH THE DEVELOPING NORTHWEST FLOW ALOFT. SHOULD ALSO
SEE ISOLATED TO SCATTERED SHOWERS AND STORMS DEVELOPING LATE THIS
MORNING OVER AND NEAR THE REST OF THE HIGHER TERRAIN SPREADING SOUTH
AND EAST ACROSS THE EASTERN PLAINS THROUGH THE AFTERNOON...WITH BEST
COVERAGE OVER NORTHERN PORTIONS OF THE SE PLAINS. THE NORTHERLY FLOW
WILL KEEP BEST LOW LEVEL MOISTURE WELL EAST OF THE AREA WITH THE
MAIN THREATS FROM STORMS TODAY BEING LIGHTNING AND GUSTY WINDS UP TO
40 MPH...THOUGH CANT RULE OUT LOCALIZED BRIEF HEAVY RAINFALL AND
SMALL HAIL WITH THE MORE INTENSE CELLS. WITH COOLING ALOFT...SHOULD
CONTINUE TO SEE BELOW SEASONAL TEMPERATURES IN THE 70S TO LOWER 80S
ACROSS THE PLAINS...50S AND 60S ACROSS THE HIGHER TERRAIN AND MAINLY
30S AT THE PEAKS...LEADING TO THE POTENTIAL FOR LIGHT SNOW
ACCUMULATIONS AOA 12K FT TODAY.
TONIGHT...SUBSIDENT NORTHWEST FLOW ALOFT CONTINUES TO MOVE ACROSS
THE STATE AND SHOULD SEE CLOUDS AND STORMS DIMINISHING FROM WEST TO
EAST THROUGH THE EVENING HOURS WITH MOSTLY CLEAR SKIES OVERNIGHT
WITH AT OR BELOW NORMAL LOWS EXPECTED TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 408 AM MDT THU AUG 28 2014
FRIDAY THE UPR TROF WL BE EAST OF THE STATE AND AN UPR RIDGE WL BE
BUILDING OVR THE AREA. RESIDUAL MSTR AND AFTERNOON INSTABILITY WL
PROBABLY LEAD TO SOME ISOLD SHOWERS AND TSTMS...MAINLY OVR THE HYR
TRRN. HIGH TEMPS ON FRI SHOULD BE CLOSE TO OR JUST SLIGHTLY BELOW
AVERAGE. SAT AN UPR TROF OVR THE NRN ROCKIES WL BRING WESTERLY FLOW
ALOFT OVR THE STATE. MSTR OVR THE AREA INCREASES A LITTLE...ALTHOUGH
THE NAM SHOWS MORE MSTR AND BETTER PCPN CHANCES THAN THE GFS. FOR
NOW WL STICK WITH JUST SOME ISOLD TO SCT POPS OVR THE HYR TRRN...BUT
IF THE NAM SOLUTION IS CORRECT...THERE COULD BE BETTER PCPN COVERAGE
WHICH ALSO SPREADS OVR THE LOWER ELEVATIONS. HIGHS ON SAT SHOULD BE
AROUND TO SLIGHTLY ABOVE AVERAGE. SAT NIGHT AN UPR TROF MOVES ACRS
CO AND THE NAM HAS SOME PCPN ACRS MUCH OF THE AREA THRU THE
NIGHT...WHILE THE GFS AND ECMWF ARE DRIER. SUN...A COLD FRONT IS
EXPECTED TO DROP INTO SERN CO IN THE AFTERNOON HOURS. THE BEST UPR
FORCING SUN IS EXPECTED TO BE NORTH OF THE AREA...BUT SOME ISOLD
PCPN MAY DEVELOP OVR THE MTNS IN THE AFTERNOON HOURS...AND SOME MAY
ALSO DEVELOP OVER THE SERN PLAINS ALONG AND BEHIND THE FRONT. DRY
WESTERLY FLOW ALOFT IS EXPECTED FOR LABOR DAY...WITH SHALLOW UPSLOPE
FLOW DEVELOPING LATE MON OVR THE ERN MTNS AND PLAINS. THE AIR MASS
LOOKS FAIRLY DRY ON MON SO WL KEEP THE FORECAST DRY. LOW LEVEL
UPSLOPE CONTINUES ON TUE AND SOME ISOLD CONVECTION MAY DEVELOP OVR
THE HYR TRRN. ON WED THE UPR FLOW BECOMES MORE SWRLY AS AN UPR TROF
MOVES INTO THE PACNW AND THE UPR TROF EXTENDS SOUTHWARD JUST OFF THE
CA COAST. MSTR STILL LOOKS LIMITED OVR THE FORECAST AREA AND MAY
JUST SEE SOME ISOLD CONVECTION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 408 AM MDT THU AUG 28 2014
ANOTHER ROUND OF ENERGY FROM THE UPPER TROUGH WILL MOVE ACROSS THE
AREA THURSDAY MORNING AND WILL RESULT IN AN EARLY START TO SHOWERS
AND STORMS ACROSS THE HIGHER TERRAIN THURSDAY MORNING WITH SHOWERS
POSSIBLE IN THE VCNTY OF ALS AND COS BY 16Z. STRONGER SHOWERS AND
STORMS WILL HOLD OFF UNTIL AFTER 18Z...THOUGH WITH MAIN PORTION OF
THE SYSTEM LIFTING NORTH...WITH KEEP VCTS AT TAF SITES AT THIS TIME
WITH BEST CHANCES OF A STORM AFFECTING THE TERMINAL AT COS. MAINLY
VFR CONDITIONS EXPECTED AT TAF SITES WITH BRIEF MVFR CONDITIONS
POSSIBLE WITH STORMS. STORMS TO DIMINISH FROM WEST TO EAST THROUGH
THE LATE AFTERNOON AND EARLY EVENING WITH CLEARING SKIES EXPECTED
OVERNIGHT.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MW
LONG TERM...28
AVIATION...MW
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
931 AM EDT THU AUG 28 2014
.UPDATE...
ISSUED AT 931 AM EDT THU AUG 28 2014
A CONTINUOUS STRATUS LAYER HAS ENSHROUDED NORTHEASTERN KENTUCKY
THROUGH THE MID-MORNING. VISIBILITIES HAVE IMPROVED IN THE
VALLEYS...WITH MOST LOCATIONS REPORTING A MILE OR ABOVE NOW. HAVE
BEEFED UP THE SKY COVER ACROSS THIS AREA AND ALSO ACCORDINGLY
TEMPERED THE DIURNAL TEMPERATURE RISE. THIS DECK WILL GRADUALLY BURN
OFF THROUGH AROUND 11 AM. HAVE ALSO RESERVED THE ISOLATED POPS UNTIL
THE AFTERNOON HOURS...ACCORDING TO THE LATEST HRRR MODEL GUIDANCE
TRENDS. THE HIGH TEMPERATURES LOOK ON TRACK. UPDATED PRODUCTS WILL
BE OUT SHORTLY.
UPDATE ISSUED AT 655 AM EDT THU AUG 28 2014
SO FAR FORECAST SEEMS TO BE WELL ON TRACK WITH ONGOING CONDITIONS.
RESIDUAL CLOUD COVER OVER THE FAR EASTERN PORTION OF THE CWA HAS
DEVELOPED AFTER SOME PASSING SHOWERS AND THUNDERSTORMS OCCURRED JUST
EAST OF OUR BORDER. OTHERWISE...FOG DEVELOPMENT /ESPECIALLY IN THE
VALLEYS/ HAS LED TO VV CIGS ACROSS PORTIONS OF EASTERN KY. FOG IS
SHOWING SIGNS OF LIFTING AT THE TAF SITES OVER THE LAST HOUR...AND AS
HAS BEEN THE CASE IN PREVIOUS MORNINGS...SHOULD CONTINUE TO LIFT AND
BURN OFF THROUGH 10AM. LOADED IN THE LATEST OBSERVATIONAL DATA TO THE
ONGOING NEAR TERM FORECAST TO MAKE SURE ONGOING TEMPERATURES...DEW
POINTS...AND WINDS WERE WELL REFLECTED.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT THU AUG 28 2014
A WEAK SURFACE COLD FRONT CONTINUES TO PUSH SOUTHWARD ACROSS THE
REGION ATTM. HIGH PRESSURE IS RETREATING JUST TO THE SOUTH OF THE
REGION...AND A BROADER AREA OF HIGH PRESSURE IS MOVING IN BEHIND THE
FRONTAL BOUNDARY TO OUR NORTH. THIS BOUNDARY IS STILL EXPECTED TO
LOSE STRENGTH AND STALL OUT JUST S OF KY BY LATE IN THE DAY TODAY.
THE EXISTENCE OF THE BOUNDARY AND WARM/HUMID TEMPERATURES WILL BE
ENOUGH TO SPAWN SOME ISOLATED CHANCES OF SHOWERS AND THUNDERSTORMS
ACROSS THE SOUTHERN EXTENT OF THE CWA DURING THIS TIME...WHILE
INCOMING HIGH PRESSURE SHOULD KEEP CONDITIONS DRY ACROSS THE NORTHERN
CWA. LOSS OF DAYTIME HEATING WILL QUICKLY BRING AN END TO ANY
CONVECTION BY THIS EVENING.
OVERALL TONIGHT LOOKS TO BE QUIET WITH JUST A FEW CLOUDS LINGERING
AROUND. BY TOMORROW...THE STATIONARY FRONT WILL MAKE SHIFT BACK
NORTHWARDS AS A WARM FRONT...ATTACHED TO SURFACE LOW QUICKLY MOVING
FROM SW TO NE ACROSS THE GREAT PLAINS STATES. BEHIND THE WARM
FRONT...A SURGE OF WARMER...MOIST...GULF AIR WILL ADVECT INTO THE
REGION. TEMPERATURES WILL RISE INTO THE UPPER 80S TO AROUND 90
ACROSS MUCH OF EASTERN KY...WITH HUMIDITY LEVELS CAUSING HEAT
INDEXES TO PEAK A FEW DEGREES HIGHER. THE FRONT WILL STILL BE
WEAK...BUT THE INFLUX OF MOISTURE AND INSTABILITY WILL BE ENOUGH TO
SPAWN ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF
KY BY THE AFTERNOON AND CONTINUING INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 420 AM EDT THU AUG 28 2014
THE MODEL CONSENSUS CONTINUES TO INDICATE THAT AN UPPER LEVEL RIDGE
OF HIGH PRESSURE WILL BE CENTERED TO OUR SOUTH OR SOUTHEAST THROUGH
MUCH OF THE PERIOD. A SHORTWAVE TROUGH WILL GRADUALLY PROGRESS FROM
THE ROCKIES INTO THE PLAINS IN THE NEAR TERM AND THEN TRACK GENERALLY
TO OUR NORTH INTO THE GREAT LAKES OVER THE WEEKEND. WEAKER
DISTURBANCES INITIALLY OVER TX OR THE WESTERN GULF OF MEXICO...OR AT
LEAST SOME OF THE DEEP MOISTURE ASSOCIATED WITH THEM ARE PROGGED TO
WORK AROUND THE BACKSIDE OF THE RIDGE AND INTO THE TN AND OH VALLEY
REGION FROM SAT INTO SUN NIGHT. THE PATTERN WILL GENERALLY THEN
EVOLVE TO A BROAD TROUGH STRETCHING FROM THE INTERMOUNTAIN WEST INTO
THE PLAINS BY THE END OF THE WEEKEND AND INTO EARLY NEXT WEEK.
HOWEVER...THE OVERALL TREND IS FOR THIS TROUGH TO FINALLY SWING EAST
TO OUR NORTH BY THE MIDDLE OF NEXT WEEK WITH OUR FLOW FLATTENING BACK
OUT. BEFORE THAT HAPPENS...A SOUTHWEST FLOW PATTERN WILL BE IN PLACE
OVER THE BLUEGRASS STATE.
AT THE SURFACE...A WARM FRONT WILL BE WORKING NORTH AND SHOULD EXIT
TO THE NORTH AND EAST EARLY IN THE PERIOD AS THE ABOVE MENTIONED
INITIAL SHORTWAVE WORKS TOWARD THE GREAT LAKES. AN ISOLATED SHOWER
OR STORM WILL REMAIN POSSIBLE EARLY IN THE PERIOD...ON FRIDAY NIGHT
AS THE REGION GETS INTO THE WARM SECTOR AND THE WARM FRONT DEPARTS.
ANOTHER COLD FRONT SHOULD SLOWLY MOVE FROM THE PLAINS OVER THE
WEEKEND...AND TOWARD THE AREA BY THE MIDDLE OF NEXT WEEK...GRADUALLY
STRETCHING OUT WEST TO EAST BY THE INCREASINGLY WEST TO EAST
ORIENTED RIDGE OVER THE SOUTHEASTERN CONUS. THE MODELS CONTINUE TO
INDICATE THAT SOUTHWEST FLOW IN ADVANCE OF THIS FRONT...IN ADDITION
TO THE PASSING OF DISTURBANCES ALOFT...WILL FUEL PERIODS OF SHOWERS
AND THUNDERSTORMS DURING THE HOLIDAY WEEKEND. THE EXACT TIMING OF
THESE DISTURBANCES REMAINS SOMEWHAT UNCERTAIN.
AT THIS TIME...IT STILL APPEARS THAT COVERAGE OF CONVECTION SHOULD
BE THE LEAST ON FRIDAY NIGHT INTO THE DAY ON SATURDAY. BY SAT EVENING
AND INTO SATURDAY NIGHT...RAIN CHANCES INCREASE AND PEAK SUNDAY AS
THE DISTURBANCES IN THE SOUTHWEST FLOW WORK OVERHEAD. MODELS
CONTINUE TO INDICATE THAT PWATS INCREASE TO AROUND TWO INCHES...IF
NOT ABOVE TWO INCHES SATURDAY NIGHT AND REMAIN AROUND TWO INCHES INTO
MONDAY. PWATS MAY LOWER SOME IN THE SOUTHERN PART OF THE AREA LATE
MONDAY INTO TUESDAY PER RECENT GUIDANCE...BUT THEY ARE EXPECTED TO
REMAIN NEARER TO TWO INCHES CLOSER TO THE OHIO RIVER IN ADVANCE OF
THE SLOWLY APPROACHING COLD FRONT. SO THE THREAT FOR HEAVY RAINFALL
REMAINS A CONCERN DURING MUCH OF THE EXTENDED PERIOD...ESPECIALLY
FROM SAT EVENING INTO LATE SUNDAY NIGHT AND POSSIBLY LATE IN THE
PERIOD ON TUE INTO TUE NIGHT AS THE NEXT FRONT SAGS INTO THE REGION.
DRIER AIR SHOULD BEGIN TO ADVECT INTO THE AREA TUESDAY NIGHT INTO
WEDNESDAY AS A COLD FRONT FINALLY SAGS INTO THE REGION. CONFIDENCE IN
THE TIMING OF THIS FEATURE REMAINS LOW...AND WE HAVE CONTINUED TO
MAINTAIN A MENTION OF SHOWERS/STORMS THROUGH THE END OF THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 701 AM EDT THU AUG 28 2014
EXPECT FOG TO BURN OFF BETWEEN 12 AND 14Z AT TAF SITES ONCE MORE
THIS MORNING...WITH VFR CONDITIONS TAKING HOLD. A WEAK FRONTAL
BOUNDARY THAT PASSED THROUGH EASTERN KY LAST NIGHT...WILL BECOME
STATIONARY JUST SOUTH OF OUR AREA TODAY. THIS WILL BRING A THREAT OF
ISOLATED SHOWERS AND THUNDERSTORMS IN THE AFTERNOON NEAR THE TN AND
VA BORDERS. ALTHOUGH IT IS A SLIGHT CHANCE...WENT AHEAD AND KEPT
MENTION OF VCTS IN KLOZ AND KSME TAF FROM PREVIOUS FORECAST DURING
THE AFTERNOON. SKIES SHOULD QUICKLY CLEAR OVERNIGHT WITH LOSS OF
DAYTIME HEATING...WITH FOG EXPECTED TO MAKE A RETURN /ESPECIALLY IN
THE VALLEYS/ ONCE MORE. WINDS WILL REMAIN LIGHT AND VARIABLE THROUGH
THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...JMW
LONG TERM...ABE/JP
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
823 AM CDT THU AUG 28 2014
.SOUNDING DISCUSSION...
CONDITIONS HAVEN/T CHANGED SIGNIFICANTLY FROM LAST EVENING/S
FLIGHT. STILL A VERY MOIST AIR MASS WITH PRECIPITABLE WATER OF
2.14 INCHES...OR ABOUT 120 PERCENT OF NORMAL FOR THIS TIME OF
YEAR. WITH THIS MUCH MOISTURE IN PLACE...ANY STORMS THAT DEVELOP
WILL BE CAPABLE OF PRODUCING VERY HIGH RAINFALL RATES. ALSO
AIDING IN RAINFALL PRODUCTION...LIGHT WINDS THROUGH MOST OF THE
COLUMN SHOULD RESULT IN A SLOW STORM MOTION. EXCEPTION WILL BE
ACROSS SOUTHWEST PORTIONS OF THE AREA WHERE THERE WILL BE MORE
INFLUENCE FROM THE UPPER LOW OVER THE NORTHWEST GULF. STORM MOTION
WILL BE CLOSER TO 15 KTS IN THIS AREA. ALSO STILL LOOKING AT AN
UNSTABLE AIR MASS WITH A LIFTED INDEX OF -4.4 AND CAPE OF AROUND
2600 J/KG. WITH DIURNAL HEATING BEING THE MAIN LIFTING MECHANISM
EXPECT MAINLY SHOWERS AND THUNDERSTORMS MAINLY IN THE AFTERNOON.
12Z BALLOON INFO: ROUTINE FLIGHT THIS MORNING WITH NO PROBLEMS.
THE BALLOON POPPED AT 7.1 MB...OR ABOUT 20.8 MILES ABOVE THE
GROUND. AT THE TIME IT POPPED...IT WAS LOCATED OVER NORTHERN LAKE
PONTCHARTRAIN.
&&
.PREV DISCUSSION... /ISSUED 346 AM CDT THU AUG 28 2014/
SHORT TERM...
NOT MUCH ON RADAR TO START OFF THE MORNING OTHER THAN A FEW SHOWERS
OFFSHORE. RAIN CHANCES WILL BE SIMILAR TO YESTERDAY FOR MOST
PORTIONS OF THE CWA EXPECT FOR LA COASTAL PARISHES WHERE POPS SHOULD
ONLY BE AROUND 30 PCT RATHER THAN 50S. THIS IS THE RESULT OF SURFACE
LOW IN THE WESTERN GULF CONTINUING TO TRACK FURTHER AWAY FROM THE
ARE. THE FCST IS IN THE MIDDLE BETWEEN THE GENERAL HRRR AND MODEST
GFS/ECMWF. EXPECTING HIGHER POPS TO BE IN THE WESTERN HALF OF THE
FORECAST AREA. MS COUNTIES MAY NOT SEE ANY CONVECTION.
LONG TERM...
AN UPPER LEVEL TROUGH MOVING EAST ACROSS THE CENTER OF THE ROCKY
MOUNTAINS THIS MORNING IS SPLITTING AN UPPER RIDGE THATS STRUGGLING
TO MAINTAIN ITSELF OVER THE SOUTHERN HALF OF THE COUNTRY AT THIS
TIME. BY DOING SO...THE GULF OF MEXICO WILL BE OPENED UP TO THE AREA
THROUGH THE WEEKEND WHICH WILL SET THE STAGE FOR EVEN HIGHER RAIN
CHANCES FRIDAY THROUGH SUNDAY. IMPULSES RIDING AROUND THE HIGH
CENTERED TO THE EAST WILL PASS OVER THE CWA THROUGH THIS PERIOD
WHICH WILL ENHANCE SHOWER AND THUNDERSTORM DEVELOPMENT. MODEL
SOUNDINGS SHOW ABUNDANT MOISTURE WILL BE IN PLACE WITH PRECIPITABLE
WATER VALUES ON THE ORDER OF 2 TO 2.25 INCHES. THUS THINKING
COVERAGE WILL BE FAIRLY WIDESPREAD AND RAINFALL RATES QUITE HEAVY.
HAVE INCREASED POPS ON SATURDAY TO 70 PERCENT AND THAT MAY NOT BE
HIGH ENOUGH. LOCALIZED FLOODING WILL LIKELY BE AN ISSUE IN SOME
AREAS. INCREASED CLOUD COVER AND WIDESPREAD CONVECTION SHOULD LIMIT
DAILY WARMING...SO HAVE KEPT HIGHS SLIGHTLY BELOW NORMAL.
RAIN CHANCES SHOULD START TO COME BACK DOWN STARTING NEXT WEEK AS
THE TROUGH TO THE NORTH FINALLY LIFTS AND UPPER RIDGE BUILDS BACK IN
ACROSS THE SOUTH. GFS AND ECMWF ARE SHOWING A TROPICAL WAVE MOVING
ACROSS THE YUCATAN PENINSULA GOING INTO THE MIDDLE OF NEXT WEEK. IT
REMAINS TO BE SEEN IF THIS SOLUTION MATERIALIZES. STILL WAY TOO FAR
OUT TO HAVE ANY CONCERN AT THIS POINT.
AVIATION...
VFR CONDITIONS WILL PREVAIL AT ALL OF THE TERMINALS THROUGH THE
FORECAST PERIOD WITH A SCATTERED TO BROKEN CU FIELD RUNNING AROUND
4-5K FEET. THERE MAY BE SOME LIGHT FOG DEVELOPMENT AROUND 10-12Z
THIS MORNING AT KASD...KHDC...AND KMCB WHICH COULD REDUCE
VISIBILITIES TO AROUND 4-5 MILES. ANY FOG SHOULD QUICKLY CLEAR AFTER
13Z...AS DAYTIME HEATING MIXES OUT THE BOUNDARY LAYER. SOME
SCATTERED CONVECTION MAY ALSO IMPACT KHUM BETWEEN 17Z AND 23Z. HAVE
INCLUDED VCTS WORDING TO REFLECT THIS RISK.
MARINE...
EAST-SOUTHEAST FLOW OF 10 TO 15 KNOTS AND SEAS OF 2 TO 4 FEET CAN BE
EXPECTED TODAY AS AN INVERTED TROUGH EXTENDING ACROSS THE WESTERN
GULF OF MEXICO SLOWLY MOVES INTO TEXAS. THIS INITIAL TROUGH WILL
MOVE INTO TEXAS TONIGHT...BUT ANOTHER INVERTED TROUGH AXIS WILL MOVE
NORTH INTO THE COASTAL WATERS TOMORROW. THIS TROUGH WILL KEEP
SOUTHEAST FLOW OF 10 TO 15 KNOTS IN PLACE THROUGH SATURDAY. SEAS
WILL INCREASE INTO THE 3 TO 5 FEET RANGE IN THE OFFSHORE WATERS AS A
1 TO 2 FOOT SWELL TRAIN DEVELOPS IN THE GULF. RIDGING WILL BUILD
WESTWARD FROM THE EASTERN GULF FOR THE LATTER HALF OF THE
WEEKEND...KEEPING SOUTHEAST FLOW OF 10 TO 15 KNOTS IN PLACE. THESE
CONDITIONS WILL PERSIST INTO TUESDAY.
DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT..
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 91 71 92 74 / 20 10 30 30
BTR 93 74 92 76 / 30 20 40 40
ASD 92 74 91 78 / 30 20 50 40
MSY 90 78 90 78 / 30 20 50 40
GPT 91 75 90 79 / 20 10 50 40
PQL 91 73 90 78 / 20 10 40 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
SOUNDING...95/DM
AVIATION/MARINE...32
SHORT/LONG...MEFFER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1017 AM CDT THU AUG 28 2014
.UPDATE...
ISSUED AT 1017 AM CDT THU AUG 28 2014
MADE SOME MINOR UPDATES TO POPS IN THE SOUTHEAST CWA AND ADJUSTED
SKY COVER BASED ON RADAR.
LATEST RAP FORECAST SOUNDINGS ARE SHOWING LIMITED INSTABILITY OVER
THE SOUTHEAST...THUS HAVE DROPPED THE MENTION OF THUNDER. WILL
TAKE A CLOSER LOOK AT TEMPERATURES LATE MORNING/EARLY AFTERNOON.
CLOUD SHIELD MIGHT HOLD TEMPERATURES BACK SOUTHEAST...BUT
ESPECIALLY THE WESTERN EDGE OF THE CLOUD SHIELD WOULD STILL HAVE A
GOOD SHOT OF REACHING FORECAST HIGHS AS WE GOT A WARM START.
UPDATE ISSUED AT 634 AM CDT THU AUG 28 2014
UPPER LOW BRUSHING BY SOUTHERN NORTH DAKOTA TODAY. RADAR AND
SURFACE REPORTS SHOW PRECIPITATION ACROSS NORTH CENTRAL SOUTH
DAKOTA. THIS AREA WILL BE ENTERING SOUTH CENTRAL/SOUTHEAST NORTH
DAKOTA THIS MORNING. AREAS OF FOG CONTINUE MAINLY FAR SOUTHWEST AND
NORTH CENTRAL. CURRENT FORECAST TRENDING WELL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT THU AUG 28 2014
NEAR TERM CONCERNS/EARLY THIS MORNING...IS LOCALIZED DENSE FOG AT
HETTINGER. HAVE NOT SEEN MUCH EXPANSION IN THIS AREA PER SURFACE
OBS AND FOG/STRATUS LOOP...THUS WILL LIKELY UTILIZE A SHORT TERM
FORECAST TO COVER THIS. MID LEVEL CLOUDS EJECTING ACROSS WESTERN
SOUTH DAKOTA MAY BE ENOUGH TO HALT RADIATIONAL COOLING AND IMPROVE
VISIBILITIES AT HETTINGER. ANOTHER EARLY MORNING CONCERN IS THE
DEVELOPMENT OF SHOWERS IN FAR SOUTH CENTRAL AND INTO THE JAMES
RIVER VALLEY. LOCAL/REGIONAL RADAR SHOWS A LARGE SWATH OF SHOWERS
AND ISOLATED THUNDERSTORMS SLOWLY EDGING NORTH WITH TIME FROM
SOUTH DAKOTA.
FOR TODAY...MAIN CHANGE IN THE FORECAST WAS TO INCREASE POPS INTO
THE LIKELY AND CATEGORICAL RANGE ACROSS THE SOUTHERN JAMES RIVER
VALLEY. ALL MODEL SOLUTIONS PEG THE SOUTHEAST WITH AT LEAST A
THIRD OF AN INCH OF RAIN...POSSIBLY EVEN HIGHER AMOUNTS...DURING
THE MORNING AND INTO MID AFTERNOON. CURRENT RAINFALL AMOUNTS IN
PIERRE SOUTH DAKOTA WOULD SUPPORT THIS WITH 0.26 INCHES REPORTED
IN A 3HR PERIOD. ENOUGH INSTABILITY PER NAM/GFS PARAMETERS AND SPC
TO WARRANT A MENTION OF ISOLATED THUNDERSTORMS. LATEST WATER VAPOR
IMAGERY SHOWS A POTENT SHORTWAVE OVER CENTRAL SOUTH DAKOTA. THIS
IS FORECAST TO SHIFT INTO THE SOUTHERN JAMES RIVER VALLEY BY 18Z
WITH STRONG VERTICAL MOTION PER H85-H3 OMEGA FIELD. GIVEN THE
EXTENSIVE COVERAGE OF SHOWERS IN SOUTH DAKOTA CURRENTLY...AND
EXCELLENT MODEL AGREEMENT ON AREAL COVERAGE AND DURATION...HAVE HIGH
CONFIDENCE WITH LIKELY/CATEGORICAL POPS IN THE SOUTHEAST. POPS
QUICKLY TAPER OFF TO THE WEST AND NORTH WITH A TRANSITION TOWARD A
A MOSTLY SUNNY SKY ELSEWHERE. WENT WITH THE COOLER NAM/GFS MOS
TEMPERATURES IN THE SOUTHEAST WITH CLOUDS AND SHOWERS PERSISTING
THROUGH THE DAY...THUS HIGHS WILL ONLY REACH THE LOWER 70S. CONTRAST
THIS TO THE FAR WEST WHERE HIGHS WILL REACH 90 DEGREES AT WILLISTON.
THIS WARMING IN THE FAR WEST IS ALSO AHEAD OF AN ADVANCING COLD
FRONT WHICH WILL MOVE ACROSS THE NORTHWEST THURSDAY EVENING...AND
INTO CENTRAL NORTH DAKOTA AFTER MIDNIGHT. MODEL CONSENSUS IS FOR A
DRY FROPA OVERNIGHT WITH INCREASING POPS AFTER THE SHORT TERM PERIOD.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 315 AM CDT THU AUG 28 2014
INITIALLY...A COLD FRONT ASSOCIATED WITH A WEAK SHORTWAVE TROUGH
WILL BE MOVING THROUGH THE STATE FRIDAY MORNING. THE GFS/ECMWF
APPEAR TO BE THE MOST ROBUST WITH PF ALONG AND BEHIND THE FRONT
ACROSS SOUTHWEST NORTH DAKOTA. WILL FOCUS ON THE SOUTHWEST AND
EVENTUALLY SOUTH CENTRAL NORTH DAKOTA FOR SCATTERED TO WIDELY
SCATTERED THUNDERSTORMS. THIS WILL BE FOLLOWED BY A FAIRLY DRY
PERIOD FRIDAY NIGHT AND SATURDAY IN WEAK SUBSIDENCE BEHIND THE
SHORTWAVE TROUGH AND THE NEXT MORE SIGNIFICANT UPPER LOW DUE IN
SATURDAY AFTERNOON AND NIGHT. MODELS SEEM TO PRETTY MUCH PEG A
LINE OF THUNDERSTORMS ALONG AND AHEAD OF THE SHORTWAVE TROUGH AND
ASSOCIATED FRONTAL BOUNDARY SATURDAY NIGHT. WITH MODEL AGREEMENT
SATURDAY NIGHT INTO SUNDAY MORNING FEEL CONFIDENT IN RAISING POPS
TO AT LEAST LIKELY WITH AN AREA OF CATEGORICAL ACROSS MUCH OF
CENTRAL NORTH DAKOTA. ON SUNDAY SUBSIDENCE BEHIND THE
COLD/OCCLUDED FRONT SHOULD BRING IN COOLER/DRIER AIR BUT CANNOT
RULE OUT WIDELY SCATTERED POST FRONTAL SHOWERS WITH COOL CYCLONIC
FLOW ALOFT. MONDAY THROUGH WEDNESDAY SEE MAINLY NORTHWEST FLOW
ALOFT WITH ISOLATED SHOWERS/THUNDERSTORMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1017 AM CDT THU AUG 28 2014
IFR CEILINGS CONTINUE AT KBIS AND KJMS AND SHOULD LIFT TO MVFR
LATE MORNING TO EARLY AFTERNOON. COULD SEE MVFR HOLD ON THROUGH
MID AFTERNOON...ESPECIALLY AT KJMS. VFR CONDITIONS EXPECTED AT
KDIK-KISN-KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...KS
LONG TERM...WAA
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
700 AM CDT THU AUG 28 2014
.UPDATE...
ISSUED AT 655 AM CDT THU AUG 28 2014
NO SIG UPDATES PLANNED THIS EARLY MORNING. RADAR SHOWS ISOLATED
WEAK RETURNS /POSSIBLE VIRGA/ IN THE AREA WITH ORGANIZED
CONVECTION JUST BEGINNING TO MOVE INTO SOUTHCENTRAL ND ATTM.
LATEST RUC AND HRRR UPDATES TRENDING TO SOMEWHAT LESS ROBUST
CONVECTION INTO OUR AREA. REGIONAL RADAR LOOP SHOWS TWO MAIN AREAS
OF ORGANIZED DEEP CONVECTION... ONE ASSOCIATED WITH THE MAIN
SURFACE LOW IN SOUTHEAST SD AND THE OTHER ASSOCIATED WITH THE
DISTURBANCE MOVING NORTHEASTWARD THROUGH CENTRAL SD.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT THU AUG 28 2014
TODAY AND TONIGHT...CONVECTION CONTINUES TO FIRE ACROSS WESTERN AND
CENTRAL SD IN ADVANCE OF A MID-LEVEL DISTURBANCE...NOW LIFTING
OUT OF THE SOUTHERN STREAM H5 TROF OVER SOUTHEAST COLORADO. BOTH
00Z AND 06Z NAM40 HAVE BEEN PRETTY AGGRESSIVE ON BRINGING THAT
INCREASED MOISTURE AND ENERGY INTO SOUTHEAST ND BY SUNRISE AND
OVER MOST OF THE AREA /ALG AND SOUTH OF HWY 2/ THROUGHOUT THE DAY.
MEANWHILE...MODELS ARE IN FAIR AGREEMENT ON BRINGING THE MAIN
SURFACE LOW CENTER INTO SOUTHEASTERN SD BY EARLY EVENING AND
ACROSS SOUTHERN MN LATER TONIGHT. WITH THAT... THE MAIN DEEP
MOISTURE PUSH SHOULD REMAIN FOCUSED WELL SOUTH OF THE RED RIVER
BASIN... THUS AM CURRENTLY DISCOUNTING THE HEAVIER PRECIP BULLS EYE
WHICH THE ROGUE 00Z GFS HAS TARGETED INTO THE SOUTHERN RED RIVER
BASIN AREA.
FRIDAY...AS CLOUDS DEPART THE WEST CENTRAL MN REGION DURING THE
EARLY MORNING WE CAN EXPECT INCREASING CLOUDS TO BEGIN DESCENDING
INTO THE AREA THROUGH NORTHEAST ND... AHEAD OF AN APPROACHING
NORTHERN STREAM COLD FRONT. SCATTERED SHOWERS AND THUNDERSTORMS
SHOULD ACCOMPANY THAT FEATURE DURING THE EARLY PART OF FRIDAY...
WITH SKIES RAPIDLY CLEARING BEHIND THE FRONT FROM NORTHWEST TO
SOUTHEAST BY LATE FRIDAY AFTERNOON AND EARLY EVENING.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU AUG 28 2014
FAST AND FURIOUS IS THE WEEKEND.
FRIDAY NIGHT THROUGH SATURDAY...A COOL AND DRY FRIDAY NIGHT SHOULD
GIVE WAY TO A SUNNY AND DRY SATURDAY. EXPECT A SEASONABLY COOL
SURFACE HIGH PRESSURE CELL TO SLIP ACROSS THE AREA THROUGH
MIDDAY... WITH INCREASING SOUTHERLY WINDS BRINGING TEMPS BACK UP
TO NEAR SEASONAL NORMALS THROUGH LATE AFTERNOON. A FLATTENED AND
FAST H5 FLOW SHOULD HAVE THE NEXT STORM SYSTEM APPROACHING FROM
THE WEST LATE SATURDAY EVENING INTO THE OVERNIGHT.
SUNDAY THROUGH WEDNESDAY...LONG WAVE TROUGH SETTLES IN OVER WESTERN
NORTH AMERICA. ALSO A LONG WAVE TROUGH MOVE ACROSS SOUTHERN
CANADA BY THE END OF THE PERIOD. LNG WAVE RIDGE OVER THE SOUTHEAST
US BUILDS NORTH BY THE END OF THE PERIOD. THE GFS IS A LITTLE
FASTER AT THE BEGINNING OF THE PERIOD AND THE ECMWF BECOMES
SLIGHTLY FASTER BY THE END OF THE PERIOD. UPPER LEVEL JET IS SOUTH
OF THE AREA SUN AND MON. THEN SHIFTS NORTH OF THE AREA BY WED.
BOTH GFS AND ECMWF PRECIP ARE TRENDING MORE TO THE SOUTHEAST OVER
THE LAST COUPLE MODEL RUNS. WILL BLEND THE TWO MODELS.
LITTLE CHANGE TO TEMPS...A DEGREE OR SO LOWER ON SUN AND A DEGREE OR
TWO HIGH FOR TUE AND WED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY NIGHT)
ISSUED AT 655 AM CDT THU AUG 28 2014
EXPECT INCREASING VFR CIGS INTO THE SOUTHERN AND CENTRAL RRV
THROUGH 16Z...WITH FAIR SKIES OVER FAR NORTHWEST MN. MID TO LOW
LEVEL CIGS WILL OVERSPREAD THE SOUTHERN TWO THIRDS OF THE FA
THROUGH THE DAYTIME WITH AREAS SHOWERS AND ISOLATED THUNDERSTORMS
MUCH OF THE DAY. LATE AFTERNOON AND EVENING HOURS WILL HAVE SCT
SKIES MOVG FROM EASTERN ND INTO NORTHWEST MN... WITH LINGERING
CLOUDS ACROSS THE FAR SOUTHEAST FA INTO THE OVERNIGHT. INCREASING
SOUTHERLY WINDS EXPECTED THROUGH THE DAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GUST
SHORT TERM...GUST
LONG TERM...GUST/HOPPES
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1126 AM MDT THU AUG 28 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM MDT THU AUG 28 2014
CURRENT WATER VAPOR IMAGERY AND UPPER AIR ANALYSIS INDICATING A
BROAD UPPER TROUGH MOVING ACROSS THE ROCKIES...WITH A DISTINCT
CIRCULATION ACROSS NORTH CENTRAL COLORADO AT THIS TIME. WATER VAPOR
IMAGERY IS ALSO INDICATING THE MAIN MONSOONAL MOISTURE PLUME HAS
PUSHED EAST ACROSS THE SOUTHERN HIGH PLAINS AND INTO THE UPPER
MIDWEST...WITH CURRENT DRY SLOT ACROSS THE SE PLAINS DECREASING AS
EMBEDDED MOISTURE ASSOCIATED WITH THE TROUGH IS MOVING EAST.
TODAY...WILL SEE NORTHWEST FLOW ALOFT INCREASING THROUGH THE DAY AS
THE UPPER TROUGH AND MAIN VORT MAX CONTINUES TO LIFT NORTH AND EAST
INTO THE THE NORTHERN HIGH PLAINS. THE LATEST NAM AND GFS CONTINUE
TO INDICATE MORE WIDESPREAD PRECIPITATION ACROSS THE AREA AND HAVE
FOLLOWED THE HIGHER RESOLUTION NSSL WRF...HRRR AND RAP WHICH SEEM TO
HAVE PICKED UP ON FURTHER NORTH MOVEMENT OF THE SYSTEM AND ARE
KEEPING THE BEST CHANCES OF SHOWERS OVER AND NEAR THE NORTHERN AND
CENTRAL MTS WITH THE DEVELOPING NORTHWEST FLOW ALOFT. SHOULD ALSO
SEE ISOLATED TO SCATTERED SHOWERS AND STORMS DEVELOPING LATE THIS
MORNING OVER AND NEAR THE REST OF THE HIGHER TERRAIN SPREADING SOUTH
AND EAST ACROSS THE EASTERN PLAINS THROUGH THE AFTERNOON...WITH BEST
COVERAGE OVER NORTHERN PORTIONS OF THE SE PLAINS. THE NORTHERLY FLOW
WILL KEEP BEST LOW LEVEL MOISTURE WELL EAST OF THE AREA WITH THE
MAIN THREATS FROM STORMS TODAY BEING LIGHTNING AND GUSTY WINDS UP TO
40 MPH...THOUGH CANT RULE OUT LOCALIZED BRIEF HEAVY RAINFALL AND
SMALL HAIL WITH THE MORE INTENSE CELLS. WITH COOLING ALOFT...SHOULD
CONTINUE TO SEE BELOW SEASONAL TEMPERATURES IN THE 70S TO LOWER 80S
ACROSS THE PLAINS...50S AND 60S ACROSS THE HIGHER TERRAIN AND MAINLY
30S AT THE PEAKS...LEADING TO THE POTENTIAL FOR LIGHT SNOW
ACCUMULATIONS AOA 12K FT TODAY.
TONIGHT...SUBSIDENT NORTHWEST FLOW ALOFT CONTINUES TO MOVE ACROSS
THE STATE AND SHOULD SEE CLOUDS AND STORMS DIMINISHING FROM WEST TO
EAST THROUGH THE EVENING HOURS WITH MOSTLY CLEAR SKIES OVERNIGHT
WITH AT OR BELOW NORMAL LOWS EXPECTED TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 408 AM MDT THU AUG 28 2014
FRIDAY THE UPR TROF WL BE EAST OF THE STATE AND AN UPR RIDGE WL BE
BUILDING OVR THE AREA. RESIDUAL MSTR AND AFTERNOON INSTABILITY WL
PROBABLY LEAD TO SOME ISOLD SHOWERS AND TSTMS...MAINLY OVR THE HYR
TRRN. HIGH TEMPS ON FRI SHOULD BE CLOSE TO OR JUST SLIGHTLY BELOW
AVERAGE. SAT AN UPR TROF OVR THE NRN ROCKIES WL BRING WESTERLY FLOW
ALOFT OVR THE STATE. MSTR OVR THE AREA INCREASES A LITTLE...ALTHOUGH
THE NAM SHOWS MORE MSTR AND BETTER PCPN CHANCES THAN THE GFS. FOR
NOW WL STICK WITH JUST SOME ISOLD TO SCT POPS OVR THE HYR TRRN...BUT
IF THE NAM SOLUTION IS CORRECT...THERE COULD BE BETTER PCPN COVERAGE
WHICH ALSO SPREADS OVR THE LOWER ELEVATIONS. HIGHS ON SAT SHOULD BE
AROUND TO SLIGHTLY ABOVE AVERAGE. SAT NIGHT AN UPR TROF MOVES ACRS
CO AND THE NAM HAS SOME PCPN ACRS MUCH OF THE AREA THRU THE
NIGHT...WHILE THE GFS AND ECMWF ARE DRIER. SUN...A COLD FRONT IS
EXPECTED TO DROP INTO SERN CO IN THE AFTERNOON HOURS. THE BEST UPR
FORCING SUN IS EXPECTED TO BE NORTH OF THE AREA...BUT SOME ISOLD
PCPN MAY DEVELOP OVR THE MTNS IN THE AFTERNOON HOURS...AND SOME MAY
ALSO DEVELOP OVER THE SERN PLAINS ALONG AND BEHIND THE FRONT. DRY
WESTERLY FLOW ALOFT IS EXPECTED FOR LABOR DAY...WITH SHALLOW UPSLOPE
FLOW DEVELOPING LATE MON OVR THE ERN MTNS AND PLAINS. THE AIR MASS
LOOKS FAIRLY DRY ON MON SO WL KEEP THE FORECAST DRY. LOW LEVEL
UPSLOPE CONTINUES ON TUE AND SOME ISOLD CONVECTION MAY DEVELOP OVR
THE HYR TRRN. ON WED THE UPR FLOW BECOMES MORE SWRLY AS AN UPR TROF
MOVES INTO THE PACNW AND THE UPR TROF EXTENDS SOUTHWARD JUST OFF THE
CA COAST. MSTR STILL LOOKS LIMITED OVR THE FORECAST AREA AND MAY
JUST SEE SOME ISOLD CONVECTION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1123 AM MDT THU AUG 28 2014
REGION IS ON THE BACKSIDE OF UPPER TROUGH. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WILL OCCUR THIS AFTERNOON WITH STORMS
MOVING SOUTHEAST AT 15 TO 20 MPH. OVERALL PRECIP...IF IT
OCCURS...WILL GENERALLY BE LIGHT AND BRIEF WITH ONLY BRIEF PDS OF
MVFR IN HEAVIER SHOWERS. WINDS WILL BE LIGHT BUT SHOULD PICK UP
FROM THE NORTHWEST AT 6 TO 12 KNTS BY LATER AFTERNOON.
VFR EXPECTED BY EARLY EVENING AT ALL 3 TAF SITES...KPUB...KALS AND
KCOS. VFR WILL LAST THROUGH TOMORROW.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MW
LONG TERM...28
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
534 PM CDT THU AUG 28 2014
.DISCUSSION...
230 PM CDT
VISIBLE IMAGERY THIS AFTERNOON SHOWS A MID/UPR LEVEL CLOUD DECK
LIFTING NORTHEAST ACROSS NORTHERN IL. REMNANTS FROM A MORNING
COMPLEX OF THUNDERSTORMS RESIDES OVER IOWA...WITH SOME CONVECTIVE
LOOK TO THE CLOUDS LINGERING INTO THIS AFTN. SFC TEMPS ACROSS THE
FORECAST AREA HAVE BEEN ABLE TO WARM INTO THE MID/UPR 70S. A FEW
POINTS SOUTH OF PONTIAC TO KANKAKEE HAVE PUSHED TO ARND 80 DEG...BUT
WITH THE LIGHT EASTERLY FLOW AT THE SFC SOME WEAK SUBSIDENCE HAS
BEEN NOTED WITH DEW POINTS BEING PUSHED INTO THE LOW 50S ALONG THE
LAKESHORE AND MID/UPR 50S INLAND.
THE MAIN CHALLENGE FOR THIS EVENING WILL FOCUS ON CONVECTIVE
CHANCES/COVERAGE...WHICH WILL CONTINUE THROUGH DAYBREAK FRI.
GUIDANCE HAS CONTINUED TO BACK OFF ON THE ARRIVAL OF PRECIP INTO THE
FORECAST AREA...WHICH SEEMS TO LINE UP RELATIVELY WELL WITH THE
CURRENT TRENDS. THE FRONTAL BOUNDARY WILL SLOWLY LIFT NORTH THIS
EVENING...BUT NOT EXPECTING MUCH IN THE WAY OF PRECIP UNTIL PERHAPS
AFT 04Z WITH A GRADUAL UPGLIDE OF PARCELS ALLOWS FOR MOISTENING.
SOME ELEVATED CONVECTION COULD BEGIN TO DEVELOP...ALTHOUGH NOT
EXPECTING MUCH COVERAGE OVERNIGHT. THE FOCUS FOR SLIGHTLY BETTER
PRECIP COVERAGE WILL REMAIN ALONG THE NORTHERN ROW OF COUNTIES IN
NORTHERN IL...HOWEVER CLOSER TO DAYBREAK FRI IT APPEARS SOME
PRECIP/CONVECTION COULD SAG SOUTHEAST AND CLIP NORTHEAST
IL/NORTHWEST IN BEFORE DISSIPATING.
WITH INCREASING CLOUD COVER TONIGHT...IT SHUD LIMIT HOW COOL TEMPS
BECOME. SO HAVE MADE ONLY MINOR ADJUSTMENTS TO THE TEMPS WITH
GENERALLY MID/UPR 60S FOR LOWS.
BEACHLER
FRIDAY AND FRIDAY NIGHT...
CLOSED UPPER LOW CURRENTLY NEAR THE COLORADO FRONT RANGE WILL SLOWLY
TRAVERSE EAST TOWARDS THE MID-MISSOURI VALLEY FRIDAY BECOMING AN
OPEN WAVE. AT THE SURFACE...BROAD AND WEAK SURFACE LOW WILL LIFT
INTO THE UPPER MIDWEST WHILE SOUTHWEST FLOW RAMPS UP THROUGH THE
COLUMN AS THE WARM FRONT LIFTS INTO THE CENTRAL GREAT LAKES. HEAT
AND HUMIDITY WILL MAKE A RETURN AS THIS OCCURS. H85 TEMPS WARMING TO
AROUND 18C WILL HELP SUPPORT MID/UPPER 80S DURING THE DAY
FRIDAY...AND SURFACE DEWPOINTS ARE PROGGED TO PUSH BACK INTO THE LOW
POSSIBLY MID 70S. THIS WILL RESULT IN MODERATE INSTABILITY
DEVELOPING DURING THE DAY...AND ONLY WEAKLY CAPPED DURING THE
AFTERNOON AS BROAD HEIGHT FALLS ASSOCIATED WITH THE UPPER WAVE START
TO OVERSPREAD THE AREA. THERE DOESNT SEEM TO BE MUCH FOCUS IN THE
LOWER LEVELS SO WOULD EXPECT ONLY SCATTERED THUNDERSTORM DEVELOPMENT
ACROSS THE REGION FRIDAY AFTERNOON/EVENING. UPPER WAVE BEGINS TO
MOVE INTO THE UPPER MIDWEST TOMORROW NIGHT AND BROAD WARM ADVECTION
OUT AHEAD DURING THE EVENING AND OVERNIGHT HOURS WILL HELP SUSTAIN
SOME CONVECTION LATE BUT WOULD EXPECT SOME NOCTURNAL DOWNTICK IN
ACTIVITY OVERNIGHT WITH THE LOW LEVEL JET FOCUSED WELL TO OUR NORTH.
GFS/NAM SEEM TO BE OVERDOING POPS MUCH OF THE DAY AND NIGHT
FRIDAY...AND OPTED TO LEAN CLOSER TO ECMWF THESE PERIODS.
THIS WEEKEND...
COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA STARTING VERY EARLY
ON SATURDAY. WHILE NOT A FAVORABLE DIURNAL TIME...WE SHOULD STILL
HAVE SOME VERY MODEST INSTABILITY IN PLACE THAT WILL SUPPORT SOME
EARLY DAY THUNDERSTORMS ALONG THE FRONTAL BOUNDARY...WHICH WOULD BE
ABLE TO EXPAND IN COVERAGE AS THE DAY PROGRESSES AND THE BOUNDARY
LAYER WARMS. IN ADDITION...GUIDANCE SUGGESTS A SECOND SHORTWAVE
WILL WRAP INTO THE AREA THAT WILL PROVIDE ADDITIONAL BROAD SCALE
ASCENT. THE ECMWF IS ABOUT SIX HOURS SLOWER WITH THIS FEATURE
COMPARED TO THE NAM/GFS...WITH THE GEM A COMPROMISE...SO THERE
REMAINS SOME UNCERTAINTY IN TIMING. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT SATURDAY NIGHT INTO SUNDAY AND WILL PROVIDE A
BRIEF RESPITE FROM THE ACTIVE WEATHER. THE ATMOSPHERE LOOKS TO
QUICKLY RELOAD HOWEVER WITH THERMAL RIDGE ONCE AGAIN STARTING TO
TILT BACK OVER THE AREA WITH H85 TEMPS AROUND 20C BY LATER IN THE
DAY SUNDAY.
NEXT WEEK...
AN ACTIVE PATTERN LOOKS TO PERSIST THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK WITH A SERIES OF WAVES PUSHING ACROSS THE REGION BRINGING
CONTINUED PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS. ANOTHER
COLD FRONT WILL PUSH ACROSS THE AREA LATER ON MONDAY WITH THE
FRONTAL BOUNDARY STALLING JUST TO OUR SOUTH. THEREAFTER...THERE IS
CONSIDERABLE UNCERTAINTY ON HOW FAR NORTH THE BOUNDARY MAY LIFT
WITH THE BEST PRECIP CHANCES FOCUSED IN THE VICINITY OF THE
FRONT AS A SERIES OF UPPER LEVEL DISTURBANCES PUSH ACROSS THE
AREA. PWATS REMAIN JUICY ALONG THE FRONT...AROUND TWO INCHES...AND
GUIDANCE SUGGESTS THAT THERE COULD BE SEVERAL CONVECTIVE COMPLEXES
NEXT WEEK WITH A CONCERN FOR HEAVY RAIN AND FLOODING SHOULD THIS
PAN OUT.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* EAST WIND ARND 8-10KT THRU LATE AFTN...WINDS TURNING SE LATER
THIS EVENING.
* SHOWERS MOVING THROUGH BTW 00-03Z...WITH POTENTIAL TSRA AFT 09Z
THRU DAYBREAK FRI.
* MVFR IN -SHRA THIS EVENING
* WINDS CONTINUE TO TURN S FRI MORNING...WITH GUSTS DEVELOPING TO
20KT MIDDAY FRI.
BEACHLER/KMD
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS AFTN SHOWS SOME THIN MID-DECK CLOUDS LIFTING
NORTHEAST ACROSS NORTHERN IL. MUCH THICKER CLOUDS AND SPOTTY
SHOWERS REMAINS OVER IOWA. SFC WINDS CONTINUE TO BE EASTERLY
ACROSS MUCH OF THE REGION...WITH A GRADUAL TURN TOWARDS SOUTHEAST
ACROSS CENTRAL IL/IN. A FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH
THIS EVENING...WITH INCREASING MOISTURE. THIS COULD AID IN SEEING
ISOLATED SHOWERS AND POSSIBLY A THUNDERSTORM LATER TONIGHT.
GUIDANCE CONTINUES TO LEAN TOWARDS THE 10-14Z FRI TIMEFRAME FOR
THE BEST COVERAGE OF SHOWERS AND ISO-TSRA DEVELOPING...BUT
CONFIDENCE REMAINS LOW WITH COVERAGE OF THUNDER. SO AT THIS TIME
HAVE HELD ONTO JUST A PROB30 GROUP. WINDS BEHIND THE FRONTAL
BOUNDARY WILL BEGIN TO TURN SOUTH AROUND DAYBREAK FRI...WITH
BETTER MIXING DEVELOPING BY LATE MORNING/EARLY AFTN. GUIDANCE
CONTINUES TO SUGGEST CONVETION COULD BEGIN TO DEVELOP YET AGAIN
LATE MORNING THROUGH THE AFTERNOON...HOWEVER FEEL THIS IS A BIT
OVERDONE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED AND TRENDS.
* MEDIUM HIGH CONFIDENCE IN -SHRA 0Z-3Z.
* MEDIUM-HIGH CONFIDENCE THAT CIGS/VSBY REMAIN VFR WITH SHOWERS.
* LOW-MEDIUM CONFIDENCE IN TIMING OF PRECIP AND COVERAGE AFTER FIRST
ROUND OF SHOWERS THIS EVENING.
* LOW CONFIDENCE IN THUNDER CHANCES/COVERAGE.
BEACHLER/KMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT...CHANCE OF TSRA.
* SATURDAY...TSRA LIKELY.
* SUNDAY...SLIGHT CHANCE OF TSRA.
* MONDAY AND TUESDAY...CHANCE OF TSRA.
* WEDNESDAY...DRY/VFR.
&&
.MARINE...
123 PM CDT
SURFACE HIGH PRESSURE OVER THE GREAT LAKES REGION THIS AFTERNOON
WILL DRIFT TO THE EAST TONIGHT IN THE WAKE OF A DEPARTING UPPER
TROUGH OVER NEW ENGLAND/QUEBEC...AND AHEAD OF ANOTHER SURFACE TROUGH
AND WEAK COLD FRONT STRETCHING FROM FAR NORTHWEST ONTARIO TO THE
CENTRAL PLAINS. WINDS ON LAKE MICHIGAN WILL SHIFT TO THE SOUTHEAST
AND EVENTUALLY SOUTH HEADING INTO FRIDAY...AS AN AREA OF SURFACE LOW
PRESSURE DEVELOPS ACROSS THE PLAINS AND LIFTS ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY. TIGHTENING OF THE PRESSURE GRADIENT
SOUTHEAST OF THE LOW TRACK WILL RESULT IN S-SE WINDS INCREASING INTO
THE 15-25 KT RANGE TONIGHT AND FRIDAY...GRADUALLY WEAKENING SATURDAY
AS THE LOW MOVES OFF TO THE NORTHEAST AND A WEAK COLD FRONT TRAILS
ACROSS THE LAKE FOLLOWED BY WEAK HIGH PRESSURE.
THIS COLD FRONT APPEARS TO DISSIPATE OR STALL ACROSS FAR SOUTHERN
LAKE MICHIGAN OR NORTHERN IL/IND LATE SATURDAY NIGHT OR EARLY SUNDAY
BEFORE DEVELOPING BACK TO THE NORTH AS A WARM FRONT SUNDAY NIGHT AS
ANOTHER AREA OF LOW PRESSURE DEVELOPS OVER THE PLAINS AND LIFTS
NORTHEAST INTO THE WESTERN/NORTHERN LAKES LATE SUNDAY NIGHT INTO
MONDAY. AGAIN...A TIGHTENING OF THE PRESSURE GRADIENT ALONG THE
SOUTHEAST PERIPHERY OF THE LOW TRACK IS EXPECTED WITH WINDS AGAIN
BECOMING SOUTHERLY INTO THE 15-25 KT RANGE ON MONDAY. ANOTHER
TRAILING COLD FRONT WILL PASS ACROSS THE LAKE MONDAY NIGHT...WITH
WEAK HIGH PRESSURE AND LIGHTER WINDS DEVELOPING TUESDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
255 PM CDT Thu Aug 28 2014
.SHORT TERM...(This evening through Friday)
ISSUED AT 255 PM CDT THU AUG 28 2014
18z/1pm surface map shows warm front extending from northern
Missouri into western Kentucky. Aloft...vigorous upper-level low is
evident on water vapor imagery over eastern Colorado/western Kansas.
Large cluster of showers/storms associated with the low developed
along the front across Iowa last night and has since weakened as it
lifted northeastward into drier air over the Upper Midwest/Great
Lakes. Convection is still ongoing along outflow boundary from
eastern Iowa into northern Missouri: however, most of this will
remain W/NW of the KILX CWA late this afternoon into the early
evening. Meanwhile, scattered convection is firing further south
along the front across western Kentucky and this is expected to
develop further north into central Illinois over the next couple of
hours. HRRR has had a good handle on the convection and have
followed its solution closely for the immediate short-term. Have
therefore gone with scattered showers/thunder across all but the far
NE CWA around Champaign and Danville this afternoon into the
evening. Think convection will be diurnally driven and will
dissipate shortly after sunset.
As upper low slowly approaches from the west, corresponding
downstream ridging will help push the warm front northward tonight
into Friday. With strongest upper support remaining west of
Illinois through the day, think convection will once again only be
scattered in nature and primarily occur during peak heating. Have
therefore gone with a mostly dry forecast during the morning,
followed by chance PoPs during the afternoon. Best rain chances
will be focused closer to the frontal boundary across the northern
two-thirds of the CWA. High temperatures on Friday will be held
down a bit by clouds/precip, but will still rise well into the 80s,
with locations along/south of I-70 perhaps hitting the 90-degree
mark.
&&
.LONG TERM...(Friday night through Thursday)
ISSUED AT 255 PM CDT THU AUG 28 2014
Upper wave currently over the Rockies expected to slowly move out
and bring rain chances to the area, particularly Friday night and
Saturday as the upper trof moves through the Midwest. Keeping the
precip around on Saturday may result in slightly cooler temperatures
by the afternoon. Once again, the cold front associated with the
upper trof moves across the region, losing its distinct baroclinic
zone and becoming more diffuse as it slows considerably just to the
southeast near the Ohio River Valley. The remaining boundary will
keep pops around for the areas in the southeastern portions of the
state through the remains of the weekend until another larger trof
moves across the country bringing more widespread rain and thunder
for Sunday night into Monday. Signif differences between the ECMWF
and the GFS with the GFS being weaker with the boundary and leaving
a more stationary focus for prolonged showers...whereas the ECMWF is
more progressive and dries out the region on Tuesday. At this
point, the ECMWF builds a weak upper ridge into the Midwest and the
GFS stays more active.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1235 PM CDT THU AUG 28 2014
Warm front currently across southern Illinois will be the main
weather-maker over the next 24 hours. 17z radar imagery continues
to show dry conditions across the KILX CWA, although scattered
showers/thunder are beginning to develop further south across
western Kentucky/far southern Illinois. This is shown quite nicely
by the 3-hr HRRR forecast, which also shows widely scattered
thunder developing further north into west-central Illinois after
20/21z. Will continue to feature a period of VCTS this afternoon
into the early evening before any diurnal convection dissipates.
Even after the afternoon showers fade away, forecast soundings are
showing mid-level cloud deck remaining in place tonight. This
should mitigate any potential fog development, with the Rapid
Refresh showing visbys at or above 6sm through 10z. Winds will be
from the E/SE at less than 10kt this afternoon and tonight, then
will become S/SE by Friday morning as the warm front lifts
northward.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...HJS
AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
105 PM CDT THU AUG 28 2014
.DISCUSSION...
310 AM CDT
MORE ACTIVE WEATHER WILL TRY TO RETURN TO THE AREA INTO THIS EVENING
FOR AT LEAST PART OF THE AREA FOLLOWING THE RATHER QUIET WEATHER
YESTERDAY. THE FORECAST WILL FOCUS ON TIMING AND COVERAGE OF
SHOWER/THUNDER CHANCES AS WELL AS TEMPERATURES...ESPECIALLY FRIDAY
WHEN THUNDERSTORMS COULD HINDER ANOTHER SUBSTANTIAL WARM UP. THE
MAIN FEATURE ON WATER VAPOR THIS MORNING IS AN UPPER LOW WHICH HAS
BEEN SLOWLY SPINNING EASTWARD ACROSS THE WESTERN U.S. THE LOW IS NOW
MAKING SLIGHTLY FASTER EASTWARD PROGRESS ACROSS COLORADO AND WYOMING
AND AMPLIFYING A RIDGE AHEAD OF IT INTO THE MID AND UPPER
MISSISSIPPI RIVER VALLEY. SEVERAL SMALLER SCALE SHORTWAVES ARE
MOVING NORTHEASTWARD AROUND THE BASE OF THE LOW AND LIFTING INTO
KANSAS AND NEBRASKA. LOOKING FURTHER NORTHWEST...A TROUGH AXIS
EXTENDS SOUTHWESTWARD FROM NORTHERN ALBERTA ACROSS CENTRAL BRITISH
COLUMBIA AND OVER THE PACIFIC WHILE A CLOSED UPPER IS DIGGING
SOUTHEASTWARD OFF THE SOUTHERN ALASKA COAST. AT THE SURFACE...HIGH
PRESSURE IS CENTERED OVER LAKE SUPERIOR WHILE A FRONTAL BOUNDARY
EXTENDS FROM THE MAINE COAST DOWN THE OHIO VALLEY AND BACK INTO THE
CENTRAL PLAINS. SURFACE LOW PRESSURE IS ORGANIZING ACROSS THE
CENTRAL AND SOUTHERN HIGH PLAINS IN CONJUNCTION WITH THE APPROACHING
UPPER LOW.
TODAY AND TONIGHT...THE UPPER RIDGE AXIS WILL BE CRESTING THE AREA
THIS MORNING AS THE ENTIRE RIDGE BROADENS INTO FRIDAY. THE SURFACE
HIGH WILL ACCELERATE EASTWARD AND BE CENTERED OVER THE LOWER ST.
LAWRENCE RIVER VALLEY BY FRIDAY. THE UPPER LOW WILL PUSH INTO THE
CENTRAL PLAINS WHILE THE ATTENDANT SURFACE LOW MOVES NORTHEASTWARD
INTO MINNESOTA TONIGHT. WARM ADVECTION AHEAD OF THE ADVANCING UPPER
TROUGH IS GENERATING SHOWERS AND THUNDERSTORMS ACROSS MUCH OF
NEBRASKA INTO SOUTHERN IOWA AND NORTHERN MISSOURI IN CONJUNCTION
WITH SEVERAL SHORTWAVES. THE WARM ADVECTION WILL SPREAD
NORTHEASTWARD WITH A SURFACE WARM FRONT ALSO MOVING NORTHEASTWARD
AND CROSSING THE LOCAL AREA TODAY. THE FOCUS OF THE ASCENT WILL BE
TO THE WEST AND NORTHWEST OF THE AREA THROUGH THE MORNING KEEPING
THE BULK OF IF NOT ALL OF THE SHOWER ACTIVITY OUT OF THE CWA.
HOWEVER...HAVE BEEN SEEING A FEW LIGHT SPRINKLES/SHOWERS ALONG AND
SOUTH OF THE SOUTHERN CWA BORDER THIS MORNING AS WELL LIKELY IN
CONJUNCTION WITH A SUBTLE MID LEVEL WAVE. EXPECT THESE TO SHIFT EAST
OF THE AREA THROUGH DAYBREAK. PRECIP CHANCES WILL INCREASE THIS
AFTERNOON HOWEVER...MAINLY ACROSS THE WESTERN HALF OF THE AREA AND
IT IS POSSIBLE THIS COULD BE A LITTLE FAST. A BETTER PUSH OF THETA-E
AND INSTABILITY MOVE ACROSS THIS EVENING...ESPECIALLY ACROSS
NORTHERN AREAS SO MAY SEE THE PEAK OF THE ACTIVITY DURING THIS TIME.
SOUTHERN AND EASTERN AREAS MAY END UP STAYING DRY FOR MUCH OF THIS
PERIOD. HIGHS TODAY WILL RANGE FROM THE UPPER 70S NORTH TO LOWER 80S
SOUTH WITH A FAIR AMOUNT OF CLOUD COVER EXPECTED.
FRIDAY...FRIDAY WILL BE A TRICKY FORECAST WITH THE POTENTIAL
FOR A NOTICEABLE WARM UP BUT ALSO A POTENTIAL TO HAVE THAT SPOILED
BY THUNDERSTORMS. THE WESTERN PERIPHERY OF THE MID LEVEL WARM AXIS
WILL BE OVER THE AREA WITH A SOUTH TO SOUTHWEST SURFACE WIND IN
PLACE. H85/H92 HIGH TEMP CLIMATOLOGY SHOWS STRONG SUPPORT FOR HIGHS
NEAR 90 WITH VALUES OF 18/23C. LATEST GUIDANCE SHOWS CONVECTION
DEVELOPING TO THE SOUTH OF THE AREA FRIDAY MORNING AND LIFTING
NORTHWARD ON THE WESTERN FLANK OF THE RIDGE AND CROSSING THE AREA
INTO THE AFTERNOON. TOUGH TO SAY IF THIS WILL BE THE CASE BUT THE
PATTERN IS CERTAINLY SUCH THAT THIS COULD OCCUR SO WILL CONTINUE
WITH POPS PRIMARILY FRIDAY AFTERNOON AND STICK WITH HIGHS IN THE MID
TO UPPER 80S FOR NOW.
FRIDAY NIGHT THROUGH MID NEXT WEEK...LARGER SCALE TROUGHING WILL BE
BUILDING INTO WESTERN NORTH AMERICA INTO SATURDAY WHICH WILL HELP
KICK THE CENTRAL PLAINS UPPER LOW NORTHEASTWARD. ANOTHER SURFACE LOW
WILL DEVELOP AND TRACK NORTHEASTWARD INTO WISCONSIN BY SATURDAY
MORNING. LATE FRIDAY NIGHT THROUGH SATURDAY MORNING WILL PROBABLY
END UP BEING THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS AS THIS
OCCURS. MORNING FRONTAL PASSAGE IS NOT ALL THAT FAVORABLE FOR SEVERE
WEATHER BUT DO EXPECT THAT SOME SORT OF LINE OR COMPLEX OF STORMS
WOULD AFFECT THE AREA...BRINGING HEAVY RAINFALL IF NOTHING ELSE.
HIGH PRESSURE RIDGING BUILDS IN NORTH OF THE AREA BEHIND THE
DEPARTING LOW. THE BIGGEST ISSUE WITH THIS HAS BEEN TIMING WITH THE
LATEST GUIDANCE FASTER THAN EARLIER RUNS KEEPING THE PRECIP CONFINED
TO SATURDAY MORNING. WILL ADJUST POPS TO BETTER FIT THIS BUT WILL
KEEP CHANCE POPS FOR SATURDAY AFTERNOON FOR NOW. H85 TEMPS COOL
BEHIND THE SYSTEM KEEPING HIGHS IN THE UPPER 70S AND LOWER 80S WITH
SLIGHTLY WARMER TEMPS SUNDAY. THE WESTERN TROUGH WILL AMPLIFY AS IT
MOVES INTO THE NORTHERN PLAINS TAKING A SURFACE LOW NORTHEAST FROM
THE NORTHERN PLAINS TO NORTHWESTERN ONTARIO LATER SUNDAY. TIMING
WILL ONCE AGAIN NEED TO BE BETTER ASSESSED BUT THIS SYSTEM WILL
BRING ANOTHER COOL FRONT ACROSS THE AREA SOME TIME MONDAY. A LOWER
AMPLITUDE UPPER FLOW BECOMES ESTABLISHED AS THE TROUGH DEPARTS WITH
HIGH PRESSURE BUILDING IN AT THE SURFACE. WIDESPREAD POP CHANCES
LOOK LOW INTO MIDWEEK BUT THE FAIRLY ZONAL FLOW WILL BE SUPPORTIVE
OF WEAK PASSING SHORTWAVES WHICH COULD TRIGGER SOME SPOTTY PRECIP AT
TIMES. HIGHS GENERALLY LOOK TO BE AROUND 80 BUT THE FLOW WILL LIKELY
BE WEAK ENOUGH TO SUPPORT LAKE COOLING AS LONG AS THE SURFACE HIGH
IS NEARBY.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT EAST FLOW ARND 5-7KT THRU LATE AFTN...WINDS TURNING SE
WITH SPEEDS INCREASING TO ARND 10KT.
* POSSIBLE SHOWERS DEVELOPING AFT 03Z...WITH BETTER COVERAGE AND
POTENTIAL TSRA AFT 09Z THRU DAYBREAK FRI.
* WINDS CONTINUE TO TURN S FRI MORNING...WITH GUSTS DEVELOPING TO
20KT MIDDAY FRI.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS AFTN SHOWS SOME THIN MID-DECK CLOUDS LIFTING
NORTHEAST ACROSS NORTHERN IL. MUCH THICKER CLOUDS AND SPOTTY
SHOWERS REMAINS OVER IOWA. SFC WINDS CONTINUE TO BE EASTERLY
ACROSS MUCH OF THE REGION...WITH A GRADUAL TURN TOWARDS SOUTHEAST
ACROSS CENTRAL IL/IN. A FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH
THIS EVENING...WITH INCREASING MOISTURE. THIS COULD AID IN SEEING
ISOLATED SHOWERS AND POSSIBLY A THUNDERSTORM LATER TONIGHT.
GUIDANCE CONTINUES TO LEAN TOWARDS THE 10-14Z FRI TIMEFRAME FOR
THE BEST COVERAGE OF SHOWERS AND ISO-TSRA DEVELOPING...BUT
CONFIDENCE REMAINS LOW WITH COVERAGE OF THUNDER. SO AT THIS TIME
HAVE HELD ONTO JUST A PROB30 GROUP. WINDS BEHIND THE FRONTAL
BOUNDARY WILL BEGIN TO TURN SOUTH AROUND DAYBREAK FRI...WITH
BETTER MIXING DEVELOPING BY LATE MORNING/EARLY AFTN. GUIDANCE
CONTINUES TO SUGGEST CONVETION COULD BEGIN TO DEVELOP YET AGAIN
LATE MORNING THROUGH THE AFTERNOON...HOWEVER FEEL THIS IS A BIT
OVERDONE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED AND TRENDS.
* HIGH CONFIDENCE IN ALL OTHER ELEMENTS THROUGH 04Z.
* MEDIUM CONFIDENCE IN TIMING OF PRECIP AND COVERAGE.
* LOW CONFIDENCE IN THUNDER CHANCES/COVERAGE.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT...CHANCE OF TSRA.
* SATURDAY...TSRA LIKELY.
* SUNDAY...SLIGHT CHANCE OF TSRA.
* MONDAY AND TUESDAY...CHANCE OF TSRA.
* WEDNESDAY...DRY/VFR.
&&
.MARINE...
300 AM...HIGH PRESSURE OVER THE LAKES REGION WILL MOVE EAST TODAY
AND TONIGHT REACHING NEW ENGLAND FRIDAY MORNING. EAST WINDS 10 TO
15 KTS WILL GRADUALLY TURN SOUTHEASTERLY THIS EVENING THEN MORE
SOUTHERLY OVERNIGHT INTO FRIDAY MORNING AND INCREASE. LOW PRESSURE
OVER THE WESTERN PLAINS WILL MOVE NORTHEAST TO MINNESOTA AND IOWA
BY FRIDAY MORNING THEN TURN NORTHEAST ACROSS THE NORTHERN LAKES
SATURDAY INTO SATURDAY EVENING. THE GRADIENT WILL TIGHTEN AHEAD OF
THIS LOW WITH 15-25KTS EXPECTED FRIDAY. THE GRADIENT WILL SLOWLY
WEAKEN FROM NORTH TO SOUTH FRIDAY NIGHT. A TRAILING COLD FRONT
FROM THIS LOW WILL THEN MOVE SOUTH ACROSS LAKE MICHIGAN SATURDAY
NIGHT INTO SUNDAY MORNING. THIS FRONT WILL THEN LIFT BACK NORTH AS
A WARM FRONT SUNDAY NIGHT AS STRONGER HIGH PRESSURE IS EXPECTED TO
MOVE ACROSS THE NORTHERN LAKES AND ONTARIO SUNDAY NIGHT AND
MONDAY. CMS
&&
.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
NATIONAL WEATHER SERVICE LINCOLN IL
1235 PM CDT Thu Aug 28 2014
.UPDATE...
ISSUED AT 1045 AM CDT THU AUG 28 2014
Morning surface analysis shows a warm front extending from
northern Missouri into the Ohio River Valley. A vigorous
upper-level low evident on water vapor imagery over western
Kansas/Nebraska has triggered a large complex of showers/thunder
north of the front across Iowa. This precip area is lifting
northeastward and will remain W/NW of the KILX CWA. Further
southeast along the front, only isolated showers are currently
observed across central Illinois. Showers/thunder will become more
numerous as the day progresses, but due to lack of strong upper
support, areal coverage will remain scattered in nature. Due to
clouds and precip, temperatures will be a bit cooler than in
previous days. Afternoon highs will range from around 80 far
northwest to the upper 80s south of I-70. Current forecast is
right on track, so no update is needed at this time.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 303 AM CDT THU AUG 28 2014
The location of the cold front appears to be just south of our
forecast area. It is forecast to return north as a warm front,
moving from SW to NE tonight. The unstable air mass extends well
north of the front all across our counties, as evidenced by the
isolated showers popping up early this morning across the northern
half of central IL. Added sprinkles to the northern counties for the
pre-dawn hours, and may need to extend the sprinkles after 12z east
toward CMI/DNV if the channel of precip continues. Otherwise,
overall thoughts on showers/storms are for a progression of chance
PoPs from west to east as the warm front begins to approach W-SW IL
in response to low pressure lifting from Nebraska into Minnesota.
The high res HRRR, ARW, and NMM along with the Canadian GEM all are
very scarce with coverage of storms over the next 12-24 hours, and
mainly in our far W-SW counties this afternoon. The 00z NAM, GFS,
and ECMWF all are a bit more aggressive, bringing precip as far east
as I-57 and LWV/Robinson. We kept the previous trends in the grids
of diurnally driven coverage, with higher chance PoPs in the SW half
of our forecast area this afternoon into early evening, then
trimming them back west later this evening/overnight. Confidence is
still low on precip coverage and timing based on very weak triggers
expected in our area northeast of the frontal boundary.
Sunshine will be filtered by mid-high clouds today, with highs in
the lower 80s north and some upper 80s S of Jacksonville to LWV.
Lows tonight will remain mainly in the lower 70s as the approaching
warm front keeps some cloud cover and higher dew points in our
area.
&&
.LONG TERM...(Friday through Wednesday)
ISSUED AT 303 AM CDT THU AUG 28 2014
Upper wave across the Rockies to make slow progress eastward
while dampening out Friday night over the Mississippi Valley.
Showers and storms Friday afternoon should be more scattered, with
a larger area of rain and storms coming in Friday night ahead of
the cold front. Have increased PoP`s to around 60% from I-55 west
by late Friday night and area-wide on Saturday.
The frontal boundary starts to become more diffuse Saturday night as
the upper wave flattens, and is difficult to discern by Sunday
morning. Have lingered the likely PoP`s across the southeast CWA
Saturday night as moisture continues to surge into the Ohio Valley,
and will keep high chance PoP`s going there into Sunday as well.
Further northwest, mainly dry conditions are on tap on Sunday.
Digging wave across the Rockies on Saturday night will be tracking
through the Mississippi Valley by Monday. Latest ECMWF draws some
cooler weather further south than the GFS, although not quite this
far south, as the west-east ridge across the lower tier of states
starts to strengthen again. Reasonable model agreement exists with
the associated cold front passing through on Monday, then hanging up
just south of I-70 as it becomes parallel to the upper flow. Showers
and storms to start moving back in Sunday night with the highest
chances on Monday. With the front hanging up, have lingered the
PoP`s across the southern CWA into Tuesday night, but did dry out
areas north as a small surface high drifts into the Great Lakes.
Rather muggy conditions to continue into early next week, with drier
air settling southward beginning Monday night behind the second
front.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1235 PM CDT THU AUG 28 2014
Warm front currently across southern Illinois will be the main
weather-maker over the next 24 hours. 17z radar imagery continues
to show dry conditions across the KILX CWA, although scattered
showers/thunder are beginning to develop further south across
western Kentucky/far southern Illinois. This is shown quite nicely
by the 3-hr HRRR forecast, which also shows widely scattered
thunder developing further north into west-central Illinois after
20/21z. Will continue to feature a period of VCTS this afternoon
into the early evening before any diurnal convection dissipates.
Even after the afternoon showers fade away, forecast soundings are
showing mid-level cloud deck remaining in place tonight. This
should mitigate any potential fog development, with the Rapid
Refresh showing visbys at or above 6sm through 10z. Winds will be
from the E/SE at less than 10kt this afternoon and tonight, then
will become S/SE by Friday morning as the warm front lifts
northward.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARNES
SHORT TERM...SHIMON
LONG TERM...GEELHART
AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS DES MOINES IA
316 PM CDT THU AUG 28 2014
.SHORT TERM /TONIGHT/...
ISSUED AT 315 PM CDT THU AUG 28 2014
PRIMARY FORECAST QUESTION FOR TONIGHT IS COVERAGE AND TIMING OF
PRECIPITATION. RECENT RADAR TRENDS AND HIGH RESOLUTION MODELS SUCH
AS THE WRF AND HRRR HAVE INDICATED A SIGNIFICANT DECREASING TREND IN
PRECIP COVERAGE LATE THIS AFTERNOON AND EVENING...HOWEVER MOST SHORT
RANGE MODELS CONTINUE TO FORECAST AN INCREASE ONCE AGAIN AFTER DARK
TONIGHT. THIS IS CONSISTENT WITH THE SYNOPTIC SCENARIO CHARACTERIZED
BY BROAD UPPER LEVEL DIFFLUENCE OVER A SATURATED ATMOSPHERE. HAVE
CARRIED GENERALLY CHANCE POPS/SCATTERED WORDING THROUGH THE NIGHT
GIVEN THE SUPPORT FOR REDEVELOPMENT...BUT HAVE LITTLE CONFIDENCE IN
DETAILS OF TIMING AND LOCATION THUS THE POP FORECAST IS BROADBRUSHED
FOR NOW. OTHERWISE LITTLE CHANGE WAS MADE TO THE ONGOING FORECAST.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 315 PM CDT THU AUG 28 2014
WITH UPPER LEVEL TROUGH STILL WEST OF THE AREA THROUGH EARLY
SATURDAY MORNING...LIKELY TO SEE SOME ADDITIONAL ROUNDS OF
THUNDERSTORMS ACROSS THE REGION THROUGH THAT TIME. OVER THE NEXT 24
TO 36 HOURS...THE HIGHEST PRECIPITABLE WATER VALUES WILL GRADUALLY
SHIFT EAST OF THE REGION AS H850 MOISTURE TRANSPORT BEGINS TO SHIFT
EAST AS WELL. BY 12Z FRIDAY...ONE ADDITIONAL WAVE...THE KICKER
WAVE...WILL BE LOCATED OVER SOUTHEAST KS/WESTERN MO. THIS SHOULD
LIFT NORTHEAST DURING THE NEXT 24 HOURS RESULTING IN INCREASING LIFT
OVER THE REGION FRIDAY AFTERNOON AND EVENING. IN COMBINATION WITH
THAT A COLD FRONT AND UPPER LEVEL LOW OVER SOUTHERN CANADA WILL
DRIFT SOUTHEAST AND ALSO AID IN DISPLACING THE TROUGH ACROSS THE
GREAT PLAINS. THROUGH THE PERIOD FRIDAY INTO EARLY SATURDAY...
ANOTHER HALF INCH TO INCH OF RAINFALL IS LIKELY TO FALL WITH THE
HEAVIER TOTALS OVER THE NORTH AND NORTHEAST PORTION OF THE FORECAST
AREA. WITH RAINFALL RATES SLOWING DOWN...FLASH FLOODING IS PROBABLY
NO LONGER A THREAT...BUT SATURATED GROUND MAY LEAD TO SOME MINOR
RUNOFF PROBLEMS AT TIMES INCLUDING SOME PONDING OF WATER AND MINOR
STREET FLOODING IN AREAS OF POOR DRAINAGE. TEMPERATURES TOMORROW
WILL LIKELY WARM A BIT IN THE SOUTHEAST IN THE LOWER 80S...AHEAD OF
THE WAVE WITH WARM AIR ADVECTION AND SOME POTENTIAL BREAKS IN THE
CLOUD COVER IN THE SOUTHEAST. AS THE COOL FRONT MOVES EAST PRECIP
CHANCES SHOULD END ACROSS THE REGION SATURDAY MORNING WITH SOME
SUNSHINE RETURNING TO THE AREA BY MORNING. HIGHS WILL BE SLIGHTLY
WARMER...BUT STILL WITHIN THE A FEW DEGREES OF HIGHS OF FRIDAY WITH
MORE SUNSHINE...BUT SOME SLIGHT COOL AIR ADVECTION. MODELS IN
GENERAL AGREEMENT WITH THE NEXT STRONG WAVE EXPECTED TO ARRIVE BY
SUNDAY AFTERNOON....WITH A RATHER WARM DAY AHEAD AS H850 RISE TO
NEAR 20C BY AFTERNOON. THE GFS SHOWS THAT PWATS WILL ONCE AGAIN RISE
TO NEAR OR SLIGHTLY ABOVE 2 INCHES ALONG THE BOUNDARY AS IT MOVES
INTO WESTERN IOWA BY 00Z. UPPER LEVEL WIND FIELDS AGAIN SHOW A
MODEST INCREASE AS A MODESTLY STRONG WAVE APPROACHES FROM THE
SOUTHWEST WITH 0-6KM BULK SHEAR OVER 40 KTS ACROSS THE AREA. THIS
SHOULD BE ENOUGH TO PROMOTE SEVERE STORMS DURING THE LATE AFTERNOON
AND EVENING HOURS. ANOTHER ROUND OF STORMS WITH OVER AN INCH OF RAIN
IN SOME OF THE HEAVIER STORMS IS EXPECTED. FINALLY...THE REMAINDER
OF THE FORECAST SUGGESTS THAT A BREAK FROM THE ACTIVE WEATHER WILL
RETURN FROM LATER ON MONDAY THROUGH WEDNESDAY...WITH SOME POTENTIAL
FOR A QUICK MOVING STORM AGAIN BY THURSDAY.
&&
.AVIATION...28/18Z
ISSUED AT 1220 PM CDT THU AUG 28 2014
MORNING SHOWERS AND THUNDERSTORMS ARE CLEARING THE AREA TO THE
NORTHEAST...BUT WILL LINGER ESPECIALLY AT MCW/OTM INTO THIS
AFTERNOON. BR AND IFR/LIFR CIGS ARE SIMILARLY TRYING TO CLEAR OUT
AND SHOULD EXIT FOD/DSM WITHIN THE NEXT HOUR OR TWO...BUT AGAIN AT
MCW/OTM MAY PERSIST LONGER AND IT IS DIFFICULT TO TELL WHETHER
THEY WILL LIFT AT ALL AT MCW TODAY. TONIGHT EXPECT MORE SHRA/TSRA
DEVELOPMENT ESPECIALLY AT FOD/MCW...ALONG WITH MORE LOWER CIGS AND
BR IN MOST AREAS AFTER MIDNIGHT. HAVE TAKEN A SHOT AT TRENDING
THIS WAY IN THE 18Z TAFS...BUT DETAILS WILL NEED TO BE REFINED
THIS EVENING/TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 315 PM CDT THU AUG 28 2014
SEVERAL ADDITIONAL EPISODES OF RAIN ARE EXPECTED THROUGH SATURDAY
MORNING AND AGAIN ANOTHER SUNDAY AFTERNOON THROUGH MONDAY MORNING.
AT THIS TIME EXPECTED RAINFALL AMOUNTS THROUGH SATURDAY MORNING WITH
EACH EVENT SHOULD BE LIGHT TO MODERATE. THIS WILL LIMIT THE LIKELIHOOD
OF FLASH FLOODING BUT STILL HAVE SOME EFFECT ON RISES ON SMALL STREAM
AND AREA RIVERS. THERE IS A GREATER RISK OF MORE SUBSTANTIAL RAINFALL
OVER PORTIONS OF THE FORECAST AREA SUNDAY EVENING. THIS TIME PERIOD
WILL BE MONITORED FOR BOTH SHORT TERM FLOODING AND RIVER FLOODING
OVER THE UPCOMING HOLIDAY WEEKEND.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEE
LONG TERM...REV
AVIATION...LEE
HYDROLOGY...REV
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
208 PM EDT THU AUG 28 2014
.UPDATE...
ISSUED AT 1229 PM EDT THU AUG 28 2014
THE STRATUS DECK HAS PROVEN TO BE AS FORMIDABLE AS ONE SEEN DURING
THE WINTER SEASON. THE LATEST VISIBLE SATELLITE TRENDS DO SHOW SOME
EROSION AND THINNING OVER THE PAST HOUR...BUT WILL HAVE TO HAVE
FURTHER REFINE THE SKY COVER INTO THE AFTERNOON AND CONSEQUENTLY
TEMPERATURE TRENDS. OUTSIDE THE THICKER CLOUD COVER...READINGS HAVE
SPIKED TO AS WARM AS THE 87 DEGREE MARK...CURRENTLY BEING REPORTED AT
KEKQ. UPDATES WILL BE FORTHCOMING.
UPDATE ISSUED AT 931 AM EDT THU AUG 28 2014
A CONTINUOUS STRATUS LAYER HAS ENSHROUDED NORTHEASTERN KENTUCKY
THROUGH THE MID-MORNING. VISIBILITIES HAVE IMPROVED IN THE
VALLEYS...WITH MOST LOCATIONS REPORTING A MILE OR ABOVE NOW. HAVE
BEEFED UP THE SKY COVER ACROSS THIS AREA AND ALSO ACCORDINGLY
TEMPERED THE DIURNAL TEMPERATURE RISE. THIS DECK WILL GRADUALLY BURN
OFF THROUGH AROUND 11 AM. HAVE ALSO RESERVED THE ISOLATED POPS UNTIL
THE AFTERNOON HOURS...ACCORDING TO THE LATEST HRRR MODEL GUIDANCE
TRENDS. THE HIGH TEMPERATURES LOOK ON TRACK. UPDATED PRODUCTS WILL
BE OUT SHORTLY.
UPDATE ISSUED AT 655 AM EDT THU AUG 28 2014
SO FAR FORECAST SEEMS TO BE WELL ON TRACK WITH ONGOING CONDITIONS.
RESIDUAL CLOUD COVER OVER THE FAR EASTERN PORTION OF THE CWA HAS
DEVELOPED AFTER SOME PASSING SHOWERS AND THUNDERSTORMS OCCURRED JUST
EAST OF OUR BORDER. OTHERWISE...FOG DEVELOPMENT /ESPECIALLY IN THE
VALLEYS/ HAS LED TO VV CIGS ACROSS PORTIONS OF EASTERN KY. FOG IS
SHOWING SIGNS OF LIFTING AT THE TAF SITES OVER THE LAST HOUR...AND AS
HAS BEEN THE CASE IN PREVIOUS MORNINGS...SHOULD CONTINUE TO LIFT AND
BURN OFF THROUGH 10AM. LOADED IN THE LATEST OBSERVATIONAL DATA TO THE
ONGOING NEAR TERM FORECAST TO MAKE SURE ONGOING TEMPERATURES...DEW
POINTS...AND WINDS WERE WELL REFLECTED.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT THU AUG 28 2014
A WEAK SURFACE COLD FRONT CONTINUES TO PUSH SOUTHWARD ACROSS THE
REGION ATTM. HIGH PRESSURE IS RETREATING JUST TO THE SOUTH OF THE
REGION...AND A BROADER AREA OF HIGH PRESSURE IS MOVING IN BEHIND THE
FRONTAL BOUNDARY TO OUR NORTH. THIS BOUNDARY IS STILL EXPECTED TO
LOSE STRENGTH AND STALL OUT JUST S OF KY BY LATE IN THE DAY TODAY.
THE EXISTENCE OF THE BOUNDARY AND WARM/HUMID TEMPERATURES WILL BE
ENOUGH TO SPAWN SOME ISOLATED CHANCES OF SHOWERS AND THUNDERSTORMS
ACROSS THE SOUTHERN EXTENT OF THE CWA DURING THIS TIME...WHILE
INCOMING HIGH PRESSURE SHOULD KEEP CONDITIONS DRY ACROSS THE NORTHERN
CWA. LOSS OF DAYTIME HEATING WILL QUICKLY BRING AN END TO ANY
CONVECTION BY THIS EVENING.
OVERALL TONIGHT LOOKS TO BE QUIET WITH JUST A FEW CLOUDS LINGERING
AROUND. BY TOMORROW...THE STATIONARY FRONT WILL MAKE SHIFT BACK
NORTHWARDS AS A WARM FRONT...ATTACHED TO SURFACE LOW QUICKLY MOVING
FROM SW TO NE ACROSS THE GREAT PLAINS STATES. BEHIND THE WARM
FRONT...A SURGE OF WARMER...MOIST...GULF AIR WILL ADVECT INTO THE
REGION. TEMPERATURES WILL RISE INTO THE UPPER 80S TO AROUND 90
ACROSS MUCH OF EASTERN KY...WITH HUMIDITY LEVELS CAUSING HEAT
INDEXES TO PEAK A FEW DEGREES HIGHER. THE FRONT WILL STILL BE
WEAK...BUT THE INFLUX OF MOISTURE AND INSTABILITY WILL BE ENOUGH TO
SPAWN ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF
KY BY THE AFTERNOON AND CONTINUING INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 420 AM EDT THU AUG 28 2014
THE MODEL CONSENSUS CONTINUES TO INDICATE THAT AN UPPER LEVEL RIDGE
OF HIGH PRESSURE WILL BE CENTERED TO OUR SOUTH OR SOUTHEAST THROUGH
MUCH OF THE PERIOD. A SHORTWAVE TROUGH WILL GRADUALLY PROGRESS FROM
THE ROCKIES INTO THE PLAINS IN THE NEAR TERM AND THEN TRACK GENERALLY
TO OUR NORTH INTO THE GREAT LAKES OVER THE WEEKEND. WEAKER
DISTURBANCES INITIALLY OVER TX OR THE WESTERN GULF OF MEXICO...OR AT
LEAST SOME OF THE DEEP MOISTURE ASSOCIATED WITH THEM ARE PROGGED TO
WORK AROUND THE BACKSIDE OF THE RIDGE AND INTO THE TN AND OH VALLEY
REGION FROM SAT INTO SUN NIGHT. THE PATTERN WILL GENERALLY THEN
EVOLVE TO A BROAD TROUGH STRETCHING FROM THE INTERMOUNTAIN WEST INTO
THE PLAINS BY THE END OF THE WEEKEND AND INTO EARLY NEXT WEEK.
HOWEVER...THE OVERALL TREND IS FOR THIS TROUGH TO FINALLY SWING EAST
TO OUR NORTH BY THE MIDDLE OF NEXT WEEK WITH OUR FLOW FLATTENING BACK
OUT. BEFORE THAT HAPPENS...A SOUTHWEST FLOW PATTERN WILL BE IN PLACE
OVER THE BLUEGRASS STATE.
AT THE SURFACE...A WARM FRONT WILL BE WORKING NORTH AND SHOULD EXIT
TO THE NORTH AND EAST EARLY IN THE PERIOD AS THE ABOVE MENTIONED
INITIAL SHORTWAVE WORKS TOWARD THE GREAT LAKES. AN ISOLATED SHOWER
OR STORM WILL REMAIN POSSIBLE EARLY IN THE PERIOD...ON FRIDAY NIGHT
AS THE REGION GETS INTO THE WARM SECTOR AND THE WARM FRONT DEPARTS.
ANOTHER COLD FRONT SHOULD SLOWLY MOVE FROM THE PLAINS OVER THE
WEEKEND...AND TOWARD THE AREA BY THE MIDDLE OF NEXT WEEK...GRADUALLY
STRETCHING OUT WEST TO EAST BY THE INCREASINGLY WEST TO EAST
ORIENTED RIDGE OVER THE SOUTHEASTERN CONUS. THE MODELS CONTINUE TO
INDICATE THAT SOUTHWEST FLOW IN ADVANCE OF THIS FRONT...IN ADDITION
TO THE PASSING OF DISTURBANCES ALOFT...WILL FUEL PERIODS OF SHOWERS
AND THUNDERSTORMS DURING THE HOLIDAY WEEKEND. THE EXACT TIMING OF
THESE DISTURBANCES REMAINS SOMEWHAT UNCERTAIN.
AT THIS TIME...IT STILL APPEARS THAT COVERAGE OF CONVECTION SHOULD
BE THE LEAST ON FRIDAY NIGHT INTO THE DAY ON SATURDAY. BY SAT EVENING
AND INTO SATURDAY NIGHT...RAIN CHANCES INCREASE AND PEAK SUNDAY AS
THE DISTURBANCES IN THE SOUTHWEST FLOW WORK OVERHEAD. MODELS
CONTINUE TO INDICATE THAT PWATS INCREASE TO AROUND TWO INCHES...IF
NOT ABOVE TWO INCHES SATURDAY NIGHT AND REMAIN AROUND TWO INCHES INTO
MONDAY. PWATS MAY LOWER SOME IN THE SOUTHERN PART OF THE AREA LATE
MONDAY INTO TUESDAY PER RECENT GUIDANCE...BUT THEY ARE EXPECTED TO
REMAIN NEARER TO TWO INCHES CLOSER TO THE OHIO RIVER IN ADVANCE OF
THE SLOWLY APPROACHING COLD FRONT. SO THE THREAT FOR HEAVY RAINFALL
REMAINS A CONCERN DURING MUCH OF THE EXTENDED PERIOD...ESPECIALLY
FROM SAT EVENING INTO LATE SUNDAY NIGHT AND POSSIBLY LATE IN THE
PERIOD ON TUE INTO TUE NIGHT AS THE NEXT FRONT SAGS INTO THE REGION.
DRIER AIR SHOULD BEGIN TO ADVECT INTO THE AREA TUESDAY NIGHT INTO
WEDNESDAY AS A COLD FRONT FINALLY SAGS INTO THE REGION. CONFIDENCE IN
THE TIMING OF THIS FEATURE REMAINS LOW...AND WE HAVE CONTINUED TO
MAINTAIN A MENTION OF SHOWERS/STORMS THROUGH THE END OF THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 208 PM EDT THU AUG 28 2014
MVFR STRATOCU WILL SCATTER OUT AND LIFT THROUGH 19Z. A FEW SHOWERS
AND A STRAY THUNDERSTORM WILL BE SEEN GENERALLY ALONG AND SOUTH OF
THE HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDORS THROUGH EARLY THIS
EVENING. GIVEN THE ISOLATED AREAL COVERAGE...DECIDED TO LEAVE OUT
ANY CONVECTIVE MENTION AT LOZ AND SME. ANY ACTIVITY WILL DIMINISH
QUICKLY BY AROUND 01Z...WITH FOG DEVELOPING ONCE AGAIN BETWEEN 05 AND
10Z. HAVE KEPT THINGS MVFR FOR THE TAF SITES...AS WINDS WILL BE
VEERING AROUND TO A LIGHT SOUTHEASTERLY COMPONENT. IFR OR WORSE FOG
IS EXPECTED ONCE AGAIN IN THE DEEPER RIVER VALLEYS. THE FOG WILL BE
BURNING OFF BY AROUND 13Z FRIDAY...WITH SOME ISOLATED CONVECTION
THREATENING ONCE AGAIN BY FRIDAY AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...JMW
LONG TERM...ABE/JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1229 PM EDT THU AUG 28 2014
.UPDATE...
ISSUED AT 1229 PM EDT THU AUG 28 2014
THE STRATUS DECK HAS PROVEN TO BE AS FORMIDABLE AS ONE SEEN DURING
THE WINTER SEASON. THE LATEST VISIBLE SATELLITE TRENDS DO SHOW SOME
EROSION AND THINNING OVER THE PAST HOUR...BUT WILL HAVE TO HAVE
FURTHER REFINE THE SKY COVER INTO THE AFTERNOON AND CONSEQUENTLY
TEMPERATURE TRENDS. OUTSIDE THE THICKER CLOUD COVER...READINGS HAVE
SPIKED TO AS WARM AS THE 87 DEGREE MARK...CURRENTLY BEING REPORTED AT
KEKQ. UPDATES WILL BE FORTHCOMING.
UPDATE ISSUED AT 931 AM EDT THU AUG 28 2014
A CONTINUOUS STRATUS LAYER HAS ENSHROUDED NORTHEASTERN KENTUCKY
THROUGH THE MID-MORNING. VISIBILITIES HAVE IMPROVED IN THE
VALLEYS...WITH MOST LOCATIONS REPORTING A MILE OR ABOVE NOW. HAVE
BEEFED UP THE SKY COVER ACROSS THIS AREA AND ALSO ACCORDINGLY
TEMPERED THE DIURNAL TEMPERATURE RISE. THIS DECK WILL GRADUALLY BURN
OFF THROUGH AROUND 11 AM. HAVE ALSO RESERVED THE ISOLATED POPS UNTIL
THE AFTERNOON HOURS...ACCORDING TO THE LATEST HRRR MODEL GUIDANCE
TRENDS. THE HIGH TEMPERATURES LOOK ON TRACK. UPDATED PRODUCTS WILL
BE OUT SHORTLY.
UPDATE ISSUED AT 655 AM EDT THU AUG 28 2014
SO FAR FORECAST SEEMS TO BE WELL ON TRACK WITH ONGOING CONDITIONS.
RESIDUAL CLOUD COVER OVER THE FAR EASTERN PORTION OF THE CWA HAS
DEVELOPED AFTER SOME PASSING SHOWERS AND THUNDERSTORMS OCCURRED JUST
EAST OF OUR BORDER. OTHERWISE...FOG DEVELOPMENT /ESPECIALLY IN THE
VALLEYS/ HAS LED TO VV CIGS ACROSS PORTIONS OF EASTERN KY. FOG IS
SHOWING SIGNS OF LIFTING AT THE TAF SITES OVER THE LAST HOUR...AND AS
HAS BEEN THE CASE IN PREVIOUS MORNINGS...SHOULD CONTINUE TO LIFT AND
BURN OFF THROUGH 10AM. LOADED IN THE LATEST OBSERVATIONAL DATA TO THE
ONGOING NEAR TERM FORECAST TO MAKE SURE ONGOING TEMPERATURES...DEW
POINTS...AND WINDS WERE WELL REFLECTED.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EDT THU AUG 28 2014
A WEAK SURFACE COLD FRONT CONTINUES TO PUSH SOUTHWARD ACROSS THE
REGION ATTM. HIGH PRESSURE IS RETREATING JUST TO THE SOUTH OF THE
REGION...AND A BROADER AREA OF HIGH PRESSURE IS MOVING IN BEHIND THE
FRONTAL BOUNDARY TO OUR NORTH. THIS BOUNDARY IS STILL EXPECTED TO
LOSE STRENGTH AND STALL OUT JUST S OF KY BY LATE IN THE DAY TODAY.
THE EXISTENCE OF THE BOUNDARY AND WARM/HUMID TEMPERATURES WILL BE
ENOUGH TO SPAWN SOME ISOLATED CHANCES OF SHOWERS AND THUNDERSTORMS
ACROSS THE SOUTHERN EXTENT OF THE CWA DURING THIS TIME...WHILE
INCOMING HIGH PRESSURE SHOULD KEEP CONDITIONS DRY ACROSS THE NORTHERN
CWA. LOSS OF DAYTIME HEATING WILL QUICKLY BRING AN END TO ANY
CONVECTION BY THIS EVENING.
OVERALL TONIGHT LOOKS TO BE QUIET WITH JUST A FEW CLOUDS LINGERING
AROUND. BY TOMORROW...THE STATIONARY FRONT WILL MAKE SHIFT BACK
NORTHWARDS AS A WARM FRONT...ATTACHED TO SURFACE LOW QUICKLY MOVING
FROM SW TO NE ACROSS THE GREAT PLAINS STATES. BEHIND THE WARM
FRONT...A SURGE OF WARMER...MOIST...GULF AIR WILL ADVECT INTO THE
REGION. TEMPERATURES WILL RISE INTO THE UPPER 80S TO AROUND 90
ACROSS MUCH OF EASTERN KY...WITH HUMIDITY LEVELS CAUSING HEAT
INDEXES TO PEAK A FEW DEGREES HIGHER. THE FRONT WILL STILL BE
WEAK...BUT THE INFLUX OF MOISTURE AND INSTABILITY WILL BE ENOUGH TO
SPAWN ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF
KY BY THE AFTERNOON AND CONTINUING INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 420 AM EDT THU AUG 28 2014
THE MODEL CONSENSUS CONTINUES TO INDICATE THAT AN UPPER LEVEL RIDGE
OF HIGH PRESSURE WILL BE CENTERED TO OUR SOUTH OR SOUTHEAST THROUGH
MUCH OF THE PERIOD. A SHORTWAVE TROUGH WILL GRADUALLY PROGRESS FROM
THE ROCKIES INTO THE PLAINS IN THE NEAR TERM AND THEN TRACK GENERALLY
TO OUR NORTH INTO THE GREAT LAKES OVER THE WEEKEND. WEAKER
DISTURBANCES INITIALLY OVER TX OR THE WESTERN GULF OF MEXICO...OR AT
LEAST SOME OF THE DEEP MOISTURE ASSOCIATED WITH THEM ARE PROGGED TO
WORK AROUND THE BACKSIDE OF THE RIDGE AND INTO THE TN AND OH VALLEY
REGION FROM SAT INTO SUN NIGHT. THE PATTERN WILL GENERALLY THEN
EVOLVE TO A BROAD TROUGH STRETCHING FROM THE INTERMOUNTAIN WEST INTO
THE PLAINS BY THE END OF THE WEEKEND AND INTO EARLY NEXT WEEK.
HOWEVER...THE OVERALL TREND IS FOR THIS TROUGH TO FINALLY SWING EAST
TO OUR NORTH BY THE MIDDLE OF NEXT WEEK WITH OUR FLOW FLATTENING BACK
OUT. BEFORE THAT HAPPENS...A SOUTHWEST FLOW PATTERN WILL BE IN PLACE
OVER THE BLUEGRASS STATE.
AT THE SURFACE...A WARM FRONT WILL BE WORKING NORTH AND SHOULD EXIT
TO THE NORTH AND EAST EARLY IN THE PERIOD AS THE ABOVE MENTIONED
INITIAL SHORTWAVE WORKS TOWARD THE GREAT LAKES. AN ISOLATED SHOWER
OR STORM WILL REMAIN POSSIBLE EARLY IN THE PERIOD...ON FRIDAY NIGHT
AS THE REGION GETS INTO THE WARM SECTOR AND THE WARM FRONT DEPARTS.
ANOTHER COLD FRONT SHOULD SLOWLY MOVE FROM THE PLAINS OVER THE
WEEKEND...AND TOWARD THE AREA BY THE MIDDLE OF NEXT WEEK...GRADUALLY
STRETCHING OUT WEST TO EAST BY THE INCREASINGLY WEST TO EAST
ORIENTED RIDGE OVER THE SOUTHEASTERN CONUS. THE MODELS CONTINUE TO
INDICATE THAT SOUTHWEST FLOW IN ADVANCE OF THIS FRONT...IN ADDITION
TO THE PASSING OF DISTURBANCES ALOFT...WILL FUEL PERIODS OF SHOWERS
AND THUNDERSTORMS DURING THE HOLIDAY WEEKEND. THE EXACT TIMING OF
THESE DISTURBANCES REMAINS SOMEWHAT UNCERTAIN.
AT THIS TIME...IT STILL APPEARS THAT COVERAGE OF CONVECTION SHOULD
BE THE LEAST ON FRIDAY NIGHT INTO THE DAY ON SATURDAY. BY SAT EVENING
AND INTO SATURDAY NIGHT...RAIN CHANCES INCREASE AND PEAK SUNDAY AS
THE DISTURBANCES IN THE SOUTHWEST FLOW WORK OVERHEAD. MODELS
CONTINUE TO INDICATE THAT PWATS INCREASE TO AROUND TWO INCHES...IF
NOT ABOVE TWO INCHES SATURDAY NIGHT AND REMAIN AROUND TWO INCHES INTO
MONDAY. PWATS MAY LOWER SOME IN THE SOUTHERN PART OF THE AREA LATE
MONDAY INTO TUESDAY PER RECENT GUIDANCE...BUT THEY ARE EXPECTED TO
REMAIN NEARER TO TWO INCHES CLOSER TO THE OHIO RIVER IN ADVANCE OF
THE SLOWLY APPROACHING COLD FRONT. SO THE THREAT FOR HEAVY RAINFALL
REMAINS A CONCERN DURING MUCH OF THE EXTENDED PERIOD...ESPECIALLY
FROM SAT EVENING INTO LATE SUNDAY NIGHT AND POSSIBLY LATE IN THE
PERIOD ON TUE INTO TUE NIGHT AS THE NEXT FRONT SAGS INTO THE REGION.
DRIER AIR SHOULD BEGIN TO ADVECT INTO THE AREA TUESDAY NIGHT INTO
WEDNESDAY AS A COLD FRONT FINALLY SAGS INTO THE REGION. CONFIDENCE IN
THE TIMING OF THIS FEATURE REMAINS LOW...AND WE HAVE CONTINUED TO
MAINTAIN A MENTION OF SHOWERS/STORMS THROUGH THE END OF THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 701 AM EDT THU AUG 28 2014
EXPECT FOG TO BURN OFF BETWEEN 12 AND 14Z AT TAF SITES ONCE MORE
THIS MORNING...WITH VFR CONDITIONS TAKING HOLD. A WEAK FRONTAL
BOUNDARY THAT PASSED THROUGH EASTERN KY LAST NIGHT...WILL BECOME
STATIONARY JUST SOUTH OF OUR AREA TODAY. THIS WILL BRING A THREAT OF
ISOLATED SHOWERS AND THUNDERSTORMS IN THE AFTERNOON NEAR THE TN AND
VA BORDERS. ALTHOUGH IT IS A SLIGHT CHANCE...WENT AHEAD AND KEPT
MENTION OF VCTS IN KLOZ AND KSME TAF FROM PREVIOUS FORECAST DURING
THE AFTERNOON. SKIES SHOULD QUICKLY CLEAR OVERNIGHT WITH LOSS OF
DAYTIME HEATING...WITH FOG EXPECTED TO MAKE A RETURN /ESPECIALLY IN
THE VALLEYS/ ONCE MORE. WINDS WILL REMAIN LIGHT AND VARIABLE THROUGH
THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...JMW
LONG TERM...ABE/JP
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
352 PM CDT THU AUG 28 2014
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 309 PM CDT THU AUG 28 2014
THE PRIMARY FORECAST CONCERN THROUGH TONIGHT WILL ONCE AGAIN
CENTER AROUND THE CHANCE OF THUNDERSTORMS...LOCALLY HEAVY
RAINFALL...AND POSSIBLE FLOODING. SHOWERS AND THUNDERSTORMS SHOULD
BE LESS WIDESPREAD AND OVERALL LESS HEAVY THAN WHAT WE SAW LAST
NIGHT. THE PRIMARY TRIGGERING MECHANISM CONTINUES TO BE AN UPPER
LEVEL TROUGH THAT HAS VERY SLOWLY BEEN SLIDING EAST ACROSS
NEBRASKA. THE 500 MB TROUGH AXIS WILL EVENTUALLY SLIDE EAST INTO
OUR CWA BY DAWN. AS LONG AS WE ARE OUT AHEAD OF THIS TROUGH AXIS
WE WILL SEE AT LEAST SOME CHANCE OF SHOWERS AND
THUNDERSTORMS...WHICH WILL BE THE CASE THROUGH THE NIGHT.
THE 18Z NAM AND A RUN OR TWO OF THE HRRR ARE NOW HINTING AT THE
POSSIBILITY OF SOME ELEVATED THUNDERSTORMS FORMING WITHIN A FEW
HOURS AFTER SUNSET AROUND HIGHWAY 281 OR A LITTLE EAST OF HIGHWAY
281. IF THESE STORMS FORM THEY WILL TRACK NORTHEAST AND COULD BE
HEAVY RAIN PRODUCERS WITH AN OUTSIDE CHANCE OF A LOW END SEVERE
HAIL OR WIND EVENT. INSTABILITY HAS BEEN RATHER LOW TODAY DUE TO
THE EXTENSIVE CLOUD COVER...WHICH IS THE PRIMARY LIMITING FACTOR
FOR SEVERE POTENTIAL. IN ADDITION...THE DEEP LAYER WIND SHEAR IS
ONLY AROUND 30 KTS...WHICH IS WEAK TO MODEST AND CERTAINLY NOT
OVERLY IMPRESSIVE FOR SEVERE POTENTIAL. THEREFORE...GIVEN A FAIRLY
SIMILAR MOIST ENVIRONMENT TO LAST NIGHT BEING LOCATED OUT AHEAD OF
THE UPPER TROUGH...WITH JUST A BIT LESS LIFT OUR PRIMARY CONCERN
WILL REALLY CONTINUE TO BE HEAVY RAIN...BUT JUST LIKELY NOT AS
WIDESPREAD AS THE OTHER NIGHT. THE GROUND IS VERY SATURATED ACROSS
PRETTY MUCH OUR ENTIRE FORECAST AREA SO ANY HEAVY RAIN WILL RESULT
IN RUNOFF AND POSSIBLE FLOODING. AM MOST CONCERNED FOR THE AREA
ALONG AND EAST OF HIGHWAY 281 BASED ON THE LATEST 18Z NAM.
OVERALL...THE PROBABILITY OF RAIN IS LOWER TONIGHT THAN LAST
NIGHT GIVEN THAT THE COVERAGE AREA WILL BE LESS AND IT IS HARD TO
PIN POINT EXACTLY WHERE THE THUNDERSTORMS WILL DEVELOP WITHIN THE
MORE BROAD FAVORABLE ZONE.
.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 309 PM CDT THU AUG 28 2014
FORECAST FOCUS IS ON THE CHANCES OF STORMS FRIDAY AND THEN CHANCES
OF SEVERE STORMS ON SUNDAY.
MODELS ARE IN GOOD AGREEMENT WITH MOVING AND TIMING OF MAJOR
FEATURES AT LEAST THROUGH MONDAY. IN GENERAL THE ATMOSPHERE IS
FORECAST TO MORPH FROM A CUTOFF LOW PATTERN BACK TO A MORE ZONAL
FLOW...SO OUT OF A HEAVY RAIN PATTERN AND BACK INTO A SEVERE WEATHER
TYPE REGIME.
THE LOW PRESSURE AREA THAT HAD BEEN PARKED OVER THE CENTRAL ROCKIES
THE LAST SEVERAL DAYS WILL EJECT EASTWARD ON FRIDAY AND LEAVE DRY
WEATHER BEHIND. AS IT MOVES THROUGH THERE WILL BE A THREAT OF
STORMS...BUT MAINLY OVER THE EASTERN THIRD OF THE AREA ON FRIDAY
AFTERNOON AND EARLY EVENING.
A RIDGE BUILDS OVER THE AREA ON SATURDAY BRINGING THE FIRST DRY AND
WARM DAY IN QUITE A WHILE. LOW CHANCES OF STORMS ARE BACK IN THE
FORECAST FOR SATURDAY NIGHT AND SUNDAY MORNING WITH A WEAK WAVE
MOVING ACROSS THE AREA.
HOWEVER...THE CHANCE OF STORMS FROM MID DAY SUNDAY INTO THE EVENING
IS MORE IMPRESSIVE. A COLD FRONT AND FAIRLY STRONG MID LEVEL WAVE
MOVE THROUGH DURING THAT TIME FRAME. MOST MODELS ARE IN AGREEMENT
WITH THE THE TIMING AN STRENGTH OF THE SYSTEM. THE STRONG
INSTABILITY AND GOOD SHEAR ARE MORE COMMON FOR MAY THAN AUGUST. SO
THERE IS A THREAT OF DAMAGING WINDS AND LARGE HAIL WITH STORMS THAT
DEVELOP. AS WITH ANY FORECAST OF CONVECTION SO MANY DAYS OUT THE
MODELS WILL LIKELY CHANGE...SO WE WILL CONTINUE TO MONITOR IT.
AS FOR THE WORK WEEK (MONDAY THROUGH THURSDAY)...OVERALL...MUCH
DRIER THAN THIS LAST WEEK...BUT HARD TO RULE OUT A HIT AND MISS
AFTERNOON AND EVENING STORM ESPECIALLY MONDAY...BUT THE MODELS ARE
STILL WAFFLING WITH TIMING AND STRENGTH OF FEATURES SO WILL LEAVE
DRY OR LOW PROBABILITIES UNTIL OUR CONFIDENCE RISES MORE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 117 PM CDT THU AUG 28 2014
THIS IS A DIFFICULT FORECAST PERIOD WITH CEILINGS BOUNCING AROUND
BETWEEN VFR AND MVFR THIS AFTERNOON AND THEN A CHANCE OF SHOWERS
AND THUNDERSTORMS. HOWEVER...THE PRECIPITATION CHANCES HAVE COME
DOWN SOME WITH STORMS BEING LESS WIDESPREAD THAN IN RECENT DAYS.
WILL SEE A SFC TROUGH AXIS TRACK THROUGH THIS EVENING INTO
TONIGHT...WHICH WILL RESULT IN LIGHT WINDS THAT COULD BE RATHER
VARIABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...EDDY
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1259 PM CDT THU AUG 28 2014
.UPDATE...
ISSUED AT 1259 PM CDT THU AUG 28 2014
ONLY SIGNIFICANT UPDATE WAS TO CLEAN UP SKY COVER...TRYING TO GET
A BETTER PICTURE OF WHERE SKIES WERE CLOUDY VS. CLEAR. CURRENT
FORECAST HIGH TEMPERATURES LOOK GOOD WITH LOWER 70S SOUTHEAST TO
AROUND 90 NORTHWEST.
UPDATE ISSUED AT 1017 AM CDT THU AUG 28 2014
MADE SOME MINOR UPDATES TO POPS IN THE SOUTHEAST CWA AND ADJUSTED
SKY COVER BASED ON RADAR.
LATEST RAP FORECAST SOUNDINGS ARE SHOWING LIMITED INSTABILITY OVER
THE SOUTHEAST...THUS HAVE DROPPED THE MENTION OF THUNDER. WILL
TAKE A CLOSER LOOK AT TEMPERATURES LATE MORNING/EARLY AFTERNOON.
CLOUD SHIELD MIGHT HOLD TEMPERATURES BACK SOUTHEAST...BUT
ESPECIALLY THE WESTERN EDGE OF THE CLOUD SHIELD WOULD STILL HAVE A
GOOD SHOT OF REACHING FORECAST HIGHS AS WE GOT A WARM START.
UPDATE ISSUED AT 634 AM CDT THU AUG 28 2014
UPPER LOW BRUSHING BY SOUTHERN NORTH DAKOTA TODAY. RADAR AND
SURFACE REPORTS SHOW PRECIPITATION ACROSS NORTH CENTRAL SOUTH
DAKOTA. THIS AREA WILL BE ENTERING SOUTH CENTRAL/SOUTHEAST NORTH
DAKOTA THIS MORNING. AREAS OF FOG CONTINUE MAINLY FAR SOUTHWEST AND
NORTH CENTRAL. CURRENT FORECAST TRENDING WELL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT THU AUG 28 2014
NEAR TERM CONCERNS/EARLY THIS MORNING...IS LOCALIZED DENSE FOG AT
HETTINGER. HAVE NOT SEEN MUCH EXPANSION IN THIS AREA PER SURFACE
OBS AND FOG/STRATUS LOOP...THUS WILL LIKELY UTILIZE A SHORT TERM
FORECAST TO COVER THIS. MID LEVEL CLOUDS EJECTING ACROSS WESTERN
SOUTH DAKOTA MAY BE ENOUGH TO HALT RADIATIONAL COOLING AND IMPROVE
VISIBILITIES AT HETTINGER. ANOTHER EARLY MORNING CONCERN IS THE
DEVELOPMENT OF SHOWERS IN FAR SOUTH CENTRAL AND INTO THE JAMES
RIVER VALLEY. LOCAL/REGIONAL RADAR SHOWS A LARGE SWATH OF SHOWERS
AND ISOLATED THUNDERSTORMS SLOWLY EDGING NORTH WITH TIME FROM
SOUTH DAKOTA.
FOR TODAY...MAIN CHANGE IN THE FORECAST WAS TO INCREASE POPS INTO
THE LIKELY AND CATEGORICAL RANGE ACROSS THE SOUTHERN JAMES RIVER
VALLEY. ALL MODEL SOLUTIONS PEG THE SOUTHEAST WITH AT LEAST A
THIRD OF AN INCH OF RAIN...POSSIBLY EVEN HIGHER AMOUNTS...DURING
THE MORNING AND INTO MID AFTERNOON. CURRENT RAINFALL AMOUNTS IN
PIERRE SOUTH DAKOTA WOULD SUPPORT THIS WITH 0.26 INCHES REPORTED
IN A 3HR PERIOD. ENOUGH INSTABILITY PER NAM/GFS PARAMETERS AND SPC
TO WARRANT A MENTION OF ISOLATED THUNDERSTORMS. LATEST WATER VAPOR
IMAGERY SHOWS A POTENT SHORTWAVE OVER CENTRAL SOUTH DAKOTA. THIS
IS FORECAST TO SHIFT INTO THE SOUTHERN JAMES RIVER VALLEY BY 18Z
WITH STRONG VERTICAL MOTION PER H85-H3 OMEGA FIELD. GIVEN THE
EXTENSIVE COVERAGE OF SHOWERS IN SOUTH DAKOTA CURRENTLY...AND
EXCELLENT MODEL AGREEMENT ON AREAL COVERAGE AND DURATION...HAVE HIGH
CONFIDENCE WITH LIKELY/CATEGORICAL POPS IN THE SOUTHEAST. POPS
QUICKLY TAPER OFF TO THE WEST AND NORTH WITH A TRANSITION TOWARD A
A MOSTLY SUNNY SKY ELSEWHERE. WENT WITH THE COOLER NAM/GFS MOS
TEMPERATURES IN THE SOUTHEAST WITH CLOUDS AND SHOWERS PERSISTING
THROUGH THE DAY...THUS HIGHS WILL ONLY REACH THE LOWER 70S. CONTRAST
THIS TO THE FAR WEST WHERE HIGHS WILL REACH 90 DEGREES AT WILLISTON.
THIS WARMING IN THE FAR WEST IS ALSO AHEAD OF AN ADVANCING COLD
FRONT WHICH WILL MOVE ACROSS THE NORTHWEST THURSDAY EVENING...AND
INTO CENTRAL NORTH DAKOTA AFTER MIDNIGHT. MODEL CONSENSUS IS FOR A
DRY FROPA OVERNIGHT WITH INCREASING POPS AFTER THE SHORT TERM PERIOD.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 315 AM CDT THU AUG 28 2014
INITIALLY...A COLD FRONT ASSOCIATED WITH A WEAK SHORTWAVE TROUGH
WILL BE MOVING THROUGH THE STATE FRIDAY MORNING. THE GFS/ECMWF
APPEAR TO BE THE MOST ROBUST WITH PF ALONG AND BEHIND THE FRONT
ACROSS SOUTHWEST NORTH DAKOTA. WILL FOCUS ON THE SOUTHWEST AND
EVENTUALLY SOUTH CENTRAL NORTH DAKOTA FOR SCATTERED TO WIDELY
SCATTERED THUNDERSTORMS. THIS WILL BE FOLLOWED BY A FAIRLY DRY
PERIOD FRIDAY NIGHT AND SATURDAY IN WEAK SUBSIDENCE BEHIND THE
SHORTWAVE TROUGH AND THE NEXT MORE SIGNIFICANT UPPER LOW DUE IN
SATURDAY AFTERNOON AND NIGHT. MODELS SEEM TO PRETTY MUCH PEG A
LINE OF THUNDERSTORMS ALONG AND AHEAD OF THE SHORTWAVE TROUGH AND
ASSOCIATED FRONTAL BOUNDARY SATURDAY NIGHT. WITH MODEL AGREEMENT
SATURDAY NIGHT INTO SUNDAY MORNING FEEL CONFIDENT IN RAISING POPS
TO AT LEAST LIKELY WITH AN AREA OF CATEGORICAL ACROSS MUCH OF
CENTRAL NORTH DAKOTA. ON SUNDAY SUBSIDENCE BEHIND THE
COLD/OCCLUDED FRONT SHOULD BRING IN COOLER/DRIER AIR BUT CANNOT
RULE OUT WIDELY SCATTERED POST FRONTAL SHOWERS WITH COOL CYCLONIC
FLOW ALOFT. MONDAY THROUGH WEDNESDAY SEE MAINLY NORTHWEST FLOW
ALOFT WITH ISOLATED SHOWERS/THUNDERSTORMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1259 PM CDT THU AUG 28 2014
MVFR CEILING AT KBIS AND IFR CEILING AT KJMS. KBIS SHOULD LIFT TO
VFR BY 20 UTC. JMS LIFTING TO MVFR EARLY AFTERNOON BUT COULD
REMAIN MVFR THOUGH LATE AFTERNOON. ONCE KJMS DOES CLEAR OUT
TONIGHT AS THE SYSTEM OVER THE PLAINS MOVES EAST...COULD SEE A
PERIOD OF POSSIBLE LOW CEILINGS AND FOG BEFORE A FRONTAL PASSAGE
FRIDAY MORNING. KBIS COULD ALSO SEE A RETURN OF LOW CLOUDS TONIGHT
UNTIL FRONT PASSES...BUT LESS CERTAIN HERE SO LEFT IT VFR FOR NOW.
KDIK...KISN AND KMOT EXPECTED TO REMAIN VFR WITH SOUTH TO
SOUTHWEST FLOW TURNING NORTH WITH CDFNT PASSAGE FRIDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...KS
LONG TERM...WAA
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
511 PM CDT THU AUG 28 2014
.UPDATE...ADDED AVIATION SECTION FOR 00Z TAF`S.
&&
.AVIATION...BNA/CKV/CSV...ISOLATED CELLS CONTINUE ACROSS MAINLY
NORTHERN MIDDLE TENNESSEE LATE THIS AFTERNOON. HRRR SHOWS
EXISTING ACTIVITY DISSIPATING DURING THE EVENING AS WE LOSE
DAYTIME HEATING. SURFACE RIDGE HAS SLIPPED TO OUR EAST WITH WEAK
RETURN FLOW NOW UNDERWAY. EXPECT FULL RADIATIONAL COOLING
OVERNIGHT, WITH LIGHT FOG POSSIBLE AT CKV AND CSV. VERY LITTLE
CHANCE OF CONVECTION ON FRIDAY, SO WE SHOULD BE VFR THE NEXT 24
HRS OUTSIDE OF EARLY MORNING FOG.
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT THU AUG 28 2014/
DISCUSSION...
LATEST RADAR IMAGERY SHOWS ISOLATED SMALL SHOWERS AND A FEW
THUNDERSTORMS HAVE DEVELOPED ALONG AND NORTH OF THE I-40 CORRIDOR.
ACTIVITY HAS BEEN GENERALLY STATIONARY OR OOZING SOUTHWARD...AND
COULD SEE SOME LOCALLY HEAVY RAINFALL AND BRIEF GUSTY WINDS AT
TIMES ALTHOUGH NOTHING STRONG OR SEVERE IS ANTICIPATED. CONVECTION
SHOULD DISSIPATE QUICKLY THIS EVENING WITH LOSS OF DAYTIME HEATING
BUT LEFT IN A SLIGHT CHANCE POP FOR NORTHERN ZONES.
DRIER AIRMASS NOTED TO OUR SOUTHEAST WITH DEWPOINTS IN THE 50S
AND PWATS WELL BELOW 1 INCH WILL ADVECT NORTHWEST INTO THE MID
STATE ON FRIDAY...KEEPING PRECIP CHANCES NIL BUT ALLOWING
AFTERNOON TEMPS TO WARM INTO THE LOW TO MID 90S. THIS DRY PERIOD
WILL BE VERY SHORT LIVED AS A SLUG OF DEEP TROPICAL MOISTURE WITH
PWATS ABOVE 2 INCHES MOVES OUT OF THE GULF AND INTO THE FORECAST
AREA ON SATURDAY AND REMAINS OVER THE AREA THROUGH SUNDAY.
SCATTERED TO NUMEROUS SHOWERS AND STORMS ARE ANTICIPATED BOTH DAYS
WITH LIKELY POPS WARRANTED...WITH MORE COVERAGE OF PRECIP LIKELY
SATURDAY NIGHT INTO SUNDAY WHEN PWATS PEAK AROUND 2.1 INCHES PER
12Z GFS. CLOUDS AND PRECIP WILL KEEP TEMPS DOWN ACCORDINGLY...BUT
DIFFICULT TO KNOW JUST HOW MUCH THIS FAR OUT IN TIME SO HAVE KEPT
HIGHS GENERALLY IN THE 80S TO AROUND 90 OVER THE WEEKEND.
PRECIP CHANCES RETURN TO MORE TYPICAL LOW LEVELS FROM MONDAY
THROUGH THE REST OF THE WEEK AS AN UPPER LEVEL RIDGE REBUILDS
ALONG THE GULF COAST AND EDGES NORTHWARD INTO OUR REGION. H5 RIDGE
DOES NOT LOOK OVERLY POTENT AT AROUND 590 DM...SO HIGHS IN THE LOW
90S WITH LOWS AROUND 70 LOOK REASONABLE FOR NEXT WEEK ALONG WITH
SOME ISOLATED TO WIDELY SCATTERED SHOWERS AND STORMS EACH DAY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ROSE
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
340 PM CDT THU AUG 28 2014
.SHORT TERM...
(Tonight and Friday)
Rain chances for the next 24 hours continue to look more promising.
The latest WSR-88D data indicate showers and thunderstorms are
developing across the Big Country. The RUC indicates this activity
will continue to develop and spread into mainly our northwestern
counties during the next 6 hours. Overnight tonight, the NAM
fragments the QPF into small areas across mainly our northwestern
counties. Given the uncertainty across our southeastern counties,
slight chance PoPs still look good there. Elsewhere, and especially
north of our Interstate 20 corridor, chance PoPs look best. As the
upper trough axis pushes farther east tomorrow, the better rain
chances will expand south and include more of our southern counties.
The main thunderstorm threats for the next 24 hours are deadly
lightning and flash flooding from locally heavy rainfall.
Huber
.LONG TERM...
(Friday night to Thursday)
While the upper trough will be east of the region Friday night and
Saturday, a weakly capped atmosphere will remain. Therefore,
isolated, mainly afternoon and evening showers and thunderstorms
will continue to be possible. The upper ridge strengthens Sunday,
however, with hot and dry conditions expected through next week.
Highs are expected mainly in the mid 90s.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 72 93 72 96 73 / 40 30 20 20 10
San Angelo 73 94 72 96 74 / 30 30 20 20 10
Junction 73 93 73 95 74 / 20 20 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 PM CDT THU AUG 28 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 329 PM CDT THU AUG 28 2014
MAIN FOCUS FOR THE NEXT 24 TO 48 HOURS IS ON THE HEAVY RAINFALL
POTENTIAL AS A FEW ROUNDS OF STORMS LIFT THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY.
AS OF MID AFTERNOON...WATER VAPOR IMAGERY OVERLAID WITH RAP 500MB
RAP HEIGHTS SHOWED THE SHORTWAVE TROUGH PUSHING OFF THE COLORADO
ROCKIES WITH WEAK IMPULSES LIFTING THROUGH THE CENTRAL PLAINS
TOWARD THE UPPER MIDWEST. ONE SUCH WAVE IS BRINGING THE SHIELD OF
MAINLY RAIN SHOWERS THIS AFTERNOON...WHILE ANOTHER ONE IS NOTED
NEAR THE TX PANHANDLE INTO SOUTHERN KANSAS. THIS ONE...ALONG WITH
THE MAIN TROUGH...WILL BE OUR PLAYER FOR FRIDAY AFTERNOON AND
EVENING.
THE SURFACE HIGH PRESSURE ANCHORED OVER THE GREAT LAKES KEPT FLOW
OF DRIER AIR...LIMITING THE FORWARD PROGRESS OF RAIN SHIELD. A LOT
OF THE MOISTURE WENT INTO SATURATION...AND COMBINED WITH THE
WEAKENING LLJ MOISTURE TRANSPORT FROM THIS MORNING...THE HEAVIER
RAINFALL DID NOT MATERIALIZE. WITH THAT SAID...THE ENVIRONMENT
WILL BEGIN TO BECOME MORE FAVORABLE TONIGHT AND RECENT 1-HR
RAINFALL TOTALS HAVE BEEN GENERALLY 0.1 TO 0.2 INCH...WITH SOME
ISOLATED 0.3-0.5 AMOUNTS.
VERY LITTLE INSTABILITY FOUND ACROSS THE AREA WHICH IS KEEPING
ACTIVITY AS SHOWERS/RAIN. WENT AHEAD AND LIMITED THUNDER CHANCES
TO ISOLATED/SCATTERED THROUGH THE OVERNIGHT HOURS...ESPECIALLY
MN/WI AREAS. IT WILL BE MORE STEADY RAINFALL. AS THE CURRENT
SHIELD OF RAIN LIFTS NORTHEAST...EXPECTING THE BACK EDGES TO FILL
IN SOME KEEPING THE HIGHER POPS IN PLACE THROUGH THE OVERNIGHT.
THE TIMING OF ANY SPECIFIC UPPER LEVEL WAVES...WITH CONFLICTING
STRENGTH IN MOISTURE TRANSPORT AND SURFACE FOCUS...LENDS A BIT
LOWER CONFIDENCE IN WHERE HEAVIEST RAINFALL WILL FALL. WHAT HAS
HIGHER CONFIDENCE IS THAT THE ATMOSPHERE SHOULD BETTER PRIMED FOR
EFFICIENT RAIN PRODUCERS. NO CHANGES TO THE IDEA THAT PWATS ARE
HIGH...WARM CLOUD DEPTHS ARE ABOVE 4 KM...AND THERE IS A
CONTINUOUS FLOW OF MOISTURE STREAMING IN FROM THE SOUTHWEST IN
ADVANCE OF THE SHORTWAVE.
PERUSAL OF 28.12Z MODELS SHOW SIGNALS FOR ANOTHER IMPULSE TO
SPARK CONVECTION OVERNIGHT ACROSS WESTERN INTO SOUTHWEST IOWA.
THIS WOULD LIFT THROUGH NORTHEAST IOWA AND SOUTHEAST MINNESOTA
EARLY MORNING. AFTER THE MORNING LLJ WEAKENS...THERE SEEMS TO NOT
BE ANOTHER KICKER UNTIL LATE FRIDAY AFTERNOON AND EVENING. AS
SUCH...THE LATE MORNING AND EARLY AFTERNOON HOURS COULD END UP
DRIER...AND HAVE TRIED TO REFLECT THIS THINKING IN THE HOURLY
POPS.
THE MORE SIGNIFICANT WAVE ARRIVES FRIDAY AFTERNOON THROUGH THE
EARLY MORNING HOURS SATURDAY. FINALLY THE MAIN SHORTWAVE TROUGH
ENERGY WILL BE FELT...AND WITH A GOOD FEED OF MOISTURE TRANSPORT
AND WARM AIR ADVECTION...THERE SHOULD BE WIDESPREAD SHOWERS AND
ISOLATED/EMBEDDED THUNDERSTORMS THROUGHOUT FROM LATE AFTERNOON
ONWARD.
ALTHOUGH THE FAVORABLE ATMOSPHERIC CONDITIONS WILL BE IN PLACE
FOR HEAVY RAINFALL TOMORROW...THE LACK OF HIGHER RAINFALL TOTALS
TODAY DAMPENS THE OVERALL FLASH FLOODING THREAT. RAINFALL TOTALS
THROUGH SATURDAY HAVE BEEN TEMPERED A BIT...AND ARE MORE IN THE
1-2 INCH RANGE. A LOT OF THE AREA CAN TAKE THIS TYPE OF RAINFALL.
OF COURSE LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE...BUT FEEL THE
OVERALL THREAT IS REDUCED COMPARED TO THE THINKING IN THE PAST 24
HOURS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 329 PM CDT THU AUG 28 2014
THE MAIN FOCUS IN THE LONG TERM IS CENTERED ON THE THREAT FOR
SEVERE WEATHER SUNDAY NIGHT INTO MONDAY. WITH THE HOLIDAY WEEKEND
APPROACHING...AND WITH MANY FOLKS PLANNING OUTDOOR ACTIVITIES...IT
IS THIS PERIOD THAT WARRANTS CLOSE WATCHING.
IN THE UPPER LEVELS...THE 28.12Z GUIDANCE FOLLOWED THE PAST
SEVERAL MODEL CYCLES IN SHOWING A DIGGING WESTERN CONUS LONGWAVE
TROUGH APPROACHING THE NORTHERN PLAINS BY SUNDAY EVENING. 250MB
JET DYNAMICS PUTS THE AREA IN A FAVORABLE RIGHT ENTRANCE
REGION...AND THIS JET STRENGTHENS BETWEEN 00-06Z MONDAY.
AT THE SURFACE...A COLD FRONT LOOKS LIKELY TO MOVE ACROSS
MINNESOTA LATE SUNDAY NIGHT...REACHING THE MISSISSIPPI RIVER EARLY
MONDAY MORNING. MUCAPE RANGES FROM 1500 TO 2000 J/KG ACROSS THE
REGION LATE SUNDAY...WITH HEALTHY PROFILES AS NCAPE VALUES
APPROACH 0.15. THIS IS AIDED BY 700-500MB LAPSE RATES AROUND
7.5C/KM. THE SHEAR ENVIRONMENT IS A BIT MUDDLED BETWEEN THE
VARIOUS GUIDANCE...BUT OVERALL 0-3KM SHEAR VALUES RANGE FROM 20 TO
30 KTS. HODOGRAPHS SHOW SOME CURVATURE BUT A LOT OF THE SHEAR IS
SPEED RELATED. OVERALL...THE CURRENT TIMING WOULD SUGGEST
CONVECTION TO DEVELOP IN THE AFTERNOON ACROSS THE EASTERN DAKOTAS
/ WESTERN INTO CENTRAL MINNESOTA...POSSIBLY AS SUPERCELLS...THEN
MERGE IN LINE SEGMENTS TOWARD THE WESTERN CWA IF MAINTAINED.
THERE ARE STRONG MOISTURE TRANSPORT SIGNALS WITH HIGHER PWATS
RETURNING...SO THERE COULD BE SOME HEALTHY RAIN PRODUCERS. THE
MAIN LIMITING FACTOR WOULD BE STORM SPEED...WHICH SHOULD BE RATHER
PROGRESSIVE. REGARDLESS...MAIN THREATS LOOK TO BE HEAVY
RAIN...DAMAGING WINDS...AND LARGE HAIL. AT THIS TIME...GIVEN
TIMING...WEST OF THE MS RIVER WOULD BE MORE FAVORABLE AND THIS
LINES UP WELL WITH THE CURRENT DAY 4 OUTLOOK FROM THE SPC.
OVERALL...WILL NEED TO WATCH THIS PERIOD.
THE FRONT SLIDES INTO WESTERN WISCONSIN MONDAY MORNING...WHICH
MAY ALLOW FOR ANOTHER ROUND OF DESTABILIZATION AND STRONG STORMS
FOR OUR EASTERN AREAS MONDAY AFTERNOON. THAT IS A BIT MORE
UNCERTAIN BUT IF THE SYSTEM SLOWS DOWN...WHICH SEEMS TO BE A
TREND...THIS PERIOD MAY NEED TO BE WATCHED CLOSER.
THE TUESDAY-THURSDAY PERIOD LOOKS TO FEATURE ZONAL UPPER LEVEL
FLOW WITH THE POSSIBILITY OF A FEW RIPPLES SLIDING THROUGH. NOT
MUCH CONSISTENCY IN THE MODEL RUNS TO ADD ANY DETAILS AT THIS
POINT. LOTS OF WEATHER TO GET THROUGH UNTIL THEN. SLIGHT CHANCES
WITH SEASONABLE TEMPERATURES LOOKS GOOD AT THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1225 PM CDT THU AUG 28 2014
TREND OF CONDITIONS IS DOWNWARD THIS PERIOD AS A VERY MOIST AIRMASS
AND A COUPLE ROUNDS OF FORCING/LIFT SPREAD ACROSS MN/IA/WI WITH IT.
FIRST ROUND OF -RA WAS SPREADING NORTHEAST ACROSS THE AREA LATE THIS
MORNING/EARLY THIS AFTERNOON...AND MARKED THE LEADING EDGE OF LOWER
VFR OR MVFR CIGS ALONG WITH SOME MVFR VSBYS IN -RA/-SHRA.
INSTABILITY HAS BEEN LIMITED SO FAR...THUS NOT MUCH FOR TSRA/CB
EXPECTED AT THE TAF SITES THRU THIS AFTERNOON/TONIGHT. IFR CIGS WERE
DEVELOPING ALONG/WEST OF I-35 ACROSS SOUTHERN MN/NORTHERN IA...
BEHIND THE LEADING BAND OF -RA. THESE LOW CLOUDS/CIGS EXPECTED TO
SPREAD EAST/NORTHEAST ACROSS THE TAF SITES TONIGHT AND PERSIST
THROUGH AT LEAST FRI MORNING...ALONG WITH SOME PERSISTENT -SHRA. MAY
YET NEED A PERIOD OR 2 OF TSRA AT EITHER KRST OR KLSE BETWEEN 00Z
AND 18Z...BUT CONFIDENCE IN TIMING IS LOW AT THIS POINT AND DID NOT
WANT TO PUT IN A LONGER PERIOD OF VCTS/CB IN THE TAFS FOR NOW.
&&
.HYDROLOGY...THROUGH SATURDAY MORNING
ISSUED AT 329 PM CDT THU AUG 28 2014
WITH LESS THAN EXPECTED RAINFALL TODAY...OVERALL TOTALS THROUGH
SATURDAY HAVE BEEN REDUCED TO THE 1.5 TO 2.5 INCH RANGE. THE SURGE
IN EFFICIENT RAIN PRODUCING ATMOSPHERIC CONDITIONS...CHARACTERIZED
BY WARM CLOUD DEPTHS 3.5 TO 4.0 KM...PWATS 1.5 TO 2.0 INCHES...AND
LOWER 70F DEWPOINTS...WILL REMAIN IN PLACE THROUGH EARLY SATURDAY.
OVERALL...THE THREAT FOR EXCESSIVE RAINFALL HAS BEEN DIMINISHED A
BIT AS THE ROUNDS OF STORMS LOOK PROGRESSIVE ENOUGH AND MUCH OF
THE AREA CAN HANDLE THE EXPECTED AMOUNTS. AS SUCH...WILL CONTINUE
THE HYDROLOGIC OUTLOOK /ESFARX/
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....ZT
AVIATION.....RRS
HYDROLOGY....ZT