Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/14/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
922 PM MDT TUE AUG 13 2013
.UPDATE...
&&
.SHORT TERM...STILL SCATTERED STORMS ACROSS THE FAR NORTHEAST
PLAINS WITH SOME HEAVY RAIN BUT MOVING JUST ENOUGH THAT IT IS NOT
CREATING MUCH OF A FLOOD THREAT. THERE IS ONE BATCH OF SHOWERS
MOVING OFF THE CONTINENTAL DIVIDE THIS HOUR BUT EXPECT MOST OF
THIS WILL DIMINISH BEFORE MAKING IT ON THE ADJACENT PLAINS. WILL
STILL LEAVE IN THE ISOLATED POPS FOR MOUNTAINS/ADJ PLAINS THE THE
MORE SCATTERED ACTIVITY PER CURRENT TRENDS.
.AVIATION...WINDS WILL CONTINUE TO SLOWLY SHIFT MORE SOUTHERLY FOR
THE REST OF THIS EVENING. STILL A SLIGHT CHANCE FOR A SPRINKLE
WITH WEAK ACTIVITY MOVING OFF THE FOOTHILLS. STILL EXPECT SLIGHTLY
DRIER AIRMASS AND WON`T MENTION IN TS IN TAFS FOR WEDNESDAY.
&&
.PREV DISCUSSION... /ISSUED 601 PM MDT TUE AUG 13 2013/
UPDATE...
SHORT TERM...THE STRONGER STORMS ARE OVER FAR EASTERN COLORADO
EARLY THIS EVENING WITH WEAK STORMS OVER THE MOUNTAINS AND NOW
DISSIPATING BEFORE MOVING ONTO THE URBAN CORRIDOR. DRIER AND
STRONGER FLOW ALOFT IS MOVING OVER THE MOUNTAINS AND ADJACENT
PLAINS AS PW VALUES HAVE FALLEN OVER WESTERN COLORADO DURING THE
DAY TIME. WILL TREND POPS DOWNWARD THIS EVENING GIVEN CURRENT
TRENDS...HOWEVER OUTFLOW BOUNDARIES FROM THE EAST COULD WORK THEIR
WAY WESTWARD AGAIN AND CREATE ADDITIONAL STORMS. WILL AT LEAST
MAINTAIN ISOLATED COVERAGE THROUGH MIDNIGHT.
AVIATION...HAVE DROPPED MENTION OF TS/RW FOR THE TIME AT
TERMINALS...BUT DID LEAVE AN VCTS FROM 01Z-04Z AT APA/DEN IN CASE
OUTFLOW BOUNDARIES MOVE THEIR WAY BACK WEST AND INTERACT WITH THE
WEAK ACTIVITY TO OUR WEST. THE RAP IS THE LONE MODEL WHICH BRINGS
SIGNIFICANT OUFLOW AND ISOLATED STORMS BACK WEST AGAIN.
STILL...OVERALL THREAT LOOKS LOW FOR NOW.
PREV DISCUSSION... /ISSUED 246 PM MDT TUE AUG 13 2013/
SHORT TERM...FOOTHILLS CONVECTION BLOSSOMING NICELY...SO FAR
MOVING EAST A BIT SLOWER THAN EXPECTED. THIS SHOULD ACCELERATE AS
AN ORGANIZED OUTFLOW BOUNDARY DEVELOPS. MEANWHILE PLAINS ARE
APPROACHING CONVECTIVE TEMPERATURE. APPEARS THERE ARE SEVERAL
WEAK BOUNDARIES OR CONVERGENCE ZONES RATHER THAN ONE BOUNDARY.
HINTS OF RICHER AIR COMING INTO THE EASTERN BORDER COUNTIES THIS
HOUR WITH DEW POINTS AROUND 60 IN MESONET DATA. STILL EXPECTING
STORMS TO DEVELOP ON THE PLAINS AHEAD OF THE FOOTHILLS BOUNDARY.
STILL PLENTY OF STORMS BACK OVER THE MOUNTAINS AS WELL...SO SOME
THREAT OF ADDITIONAL DEVELOPMENT FROM EITHER DIRECTION THIS
EVENING. THERE WILL EVENTUALLY BE SOME DRYING COMING FROM THE
WEST...THIS MAY AFFECT THE SW PARTS OF OUR AREA THIS EVENING WITH
A MORE NORMAL EVENING DECREASE...BUT NOT SURE WE CAN REDUCE POPS
ANYWHERE ELSE UNTIL LATER.
FOR WEDNESDAY...DRIER AIR WILL BE EDGING EASTWARD WITH A LITTLE
WARMING ALOFT. WEAK NORTH TO NORTHEAST FLOW EXPECTED AT THE
SURFACE...WHICH MAY HOLD IN A SHALLOWER COOL MOIST LAYER. IT WILL
LIKELY BE A LOW CAPE DAY...AND IF THE MOISTURE MIXES OUT WELL IN
THE AFTERNOON THEN WE COULD HAVE MUCH LESS CONVECTION. FOR NOW I
JUST SHOWED A BIT MORE OF A DIURNAL TREND WITH LESS SHOWERS IN THE
LATE NIGHT AND MORNING HOURS...MAINLY ISOLATED STORMS ON THE
PLAINS IN THE AFTERNOON WITH HIGHER CHANCES OVER THE RIDGES AND IN
DEEPER MOISTURE NEAR THE EASTERN BORDER LATE IN THE DAY. RAISED
FORECAST HIGHS A LITTLE WITH SOME SUNSHINE AND THE WARMING ALOFT.
SHOULD BE LESS OF A HEAVY RAIN THREAT...STILL A LOW SEVERE THREAT
BUT ALSO PROBABLY A BIT LESS THAN TODAY.
LONG TERM...AN UPPER LEVEL RIDGE BUILDING OVER THE WEST WILL
ALLOW FOR A DRIER NORTHERLY FLOW ALOFT OVER THE CWFA FOR THURSDAY
THROUGH SATURDAY. BEST CHC FOR TSTMS WILL BE OVER THE MTNS AND
FAR EASTERN PLAINS. OVER THE WEEKEND...THUNDERSTORMS WILL INCREASE
OVER THE MOUNTAINS ON SATURDAY...WITH THE FLOW ALOFT BECOMING
SOUTHWESTERLY AS THE RIDGE GETS SHIFTS TO THE SOUTH AND EAST.
SUNDAY AND MONDAY WILL BE MORE UNSETTLED AS AN UPPER LEVEL TROUGH
IS PROGGED TO MOVE OVER NORTHERN COLORADO. THERE WILL BE A BETTER
CHANCE OF SHOWERS AND TSTMS AT THAT TIME WITH SLIGHTLY COOLER
TEMPERATURES BY MONDAY AS WELL.
AVIATION...SCATTERED THUNDERSTORMS EXPECTED IN THE DENVER AREA
MAINLY BETWEEN 21Z AND 00Z...STILL A LOW THREAT THIS EVENING. MAIN
IMPACT WILL BE VARIABLE WIND GUSTS TO 30 KNOTS. VFR PREVAILING BUT
LOCALIZED IFR CONDITIONS UNDER THE HEAVIEST CELLS. COULD BE ENOUGH
STORMS TO REQUIRE INSTRUMENT APPROACHES TO KDEN AT TIMES...MAINLY
THROUGH 00Z. LESS THUNDERSTORM ACTIVITY EXPECTED WEDNESDAY WITH
LITTLE IMPACT.
HYDROLOGY...SLOW MOVING THUNDERSTORMS WITH HEAVY RAIN IN THE
STRONGER CELLS THIS AFTERNOON AND EVENING. RAINFALL OF UP TO 1
INCH IN AN HOUR IS POSSIBLE IN THE MOUNTAINS...AND 1.5 INCHES IN
AN HOUR ON THE PLAINS. THERE IS A LOW THREAT OF FLASH
FLOODING...MAINLY FOR THE FOOTHILLS BURN AREAS THIS AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
601 PM MDT TUE AUG 13 2013
.UPDATE...
&&
.SHORT TERM...THE STRONGER STORMS ARE OVER FAR EASTERN COLORADO
EARLY THIS EVENING WITH WEAK STORMS OVER THE MOUNTAINS AND NOW
DISSIPATING BEFORE MOVING ONTO THE URBAN CORRIDOR. DRIER AND
STRONGER FLOW ALOFT IS MOVING OVER THE MOUNTAINS AND ADJACENT
PLAINS AS PW VALUES HAVE FALLEN OVER WESTERN COLORADO DURING THE
DAY TIME. WILL TREND POPS DOWNWARD THIS EVENING GIVEN CURRENT
TRENDS...HOWEVER OUTFLOW BOUNDARIES FROM THE EAST COULD WORK THEIR
WAY WESTWARD AGAIN AND CREATE ADDITIONAL STORMS. WILL AT LEAST
MAINTAIN ISOLATED COVERAGE THROUGH MIDNIGHT.
.AVIATION...HAVE DROPPED MENTION OF TS/RW FOR THE TIME AT
TERMINALS...BUT DID LEAVE AN VCTS FROM 01Z-04Z AT APA/DEN IN CASE
OUTFLOW BOUNDARIES MOVE THEIR WAY BACK WEST AND INTERACT WITH THE
WEAK ACTIVITY TO OUR WEST. THE RAP IS THE LONE MODEL WHICH BRINGS
SIGNIFICANT OUFLOW AND ISOLATED STORMS BACK WEST AGAIN.
STILL...OVERALL THREAT LOOKS LOW FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 246 PM MDT TUE AUG 13 2013/
SHORT TERM...FOOTHILLS CONVECTION BLOSSOMING NICELY...SO FAR
MOVING EAST A BIT SLOWER THAN EXPECTED. THIS SHOULD ACCELERATE AS
AN ORGANIZED OUTFLOW BOUNDARY DEVELOPS. MEANWHILE PLAINS ARE
APPROACHING CONVECTIVE TEMPERATURE. APPEARS THERE ARE SEVERAL
WEAK BOUNDARIES OR CONVERGENCE ZONES RATHER THAN ONE BOUNDARY.
HINTS OF RICHER AIR COMING INTO THE EASTERN BORDER COUNTIES THIS
HOUR WITH DEW POINTS AROUND 60 IN MESONET DATA. STILL EXPECTING
STORMS TO DEVELOP ON THE PLAINS AHEAD OF THE FOOTHILLS BOUNDARY.
STILL PLENTY OF STORMS BACK OVER THE MOUNTAINS AS WELL...SO SOME
THREAT OF ADDITIONAL DEVELOPMENT FROM EITHER DIRECTION THIS
EVENING. THERE WILL EVENTUALLY BE SOME DRYING COMING FROM THE
WEST...THIS MAY AFFECT THE SW PARTS OF OUR AREA THIS EVENING WITH
A MORE NORMAL EVENING DECREASE...BUT NOT SURE WE CAN REDUCE POPS
ANYWHERE ELSE UNTIL LATER.
FOR WEDNESDAY...DRIER AIR WILL BE EDGING EASTWARD WITH A LITTLE
WARMING ALOFT. WEAK NORTH TO NORTHEAST FLOW EXPECTED AT THE
SURFACE...WHICH MAY HOLD IN A SHALLOWER COOL MOIST LAYER. IT WILL
LIKELY BE A LOW CAPE DAY...AND IF THE MOISTURE MIXES OUT WELL IN
THE AFTERNOON THEN WE COULD HAVE MUCH LESS CONVECTION. FOR NOW I
JUST SHOWED A BIT MORE OF A DIURNAL TREND WITH LESS SHOWERS IN THE
LATE NIGHT AND MORNING HOURS...MAINLY ISOLATED STORMS ON THE
PLAINS IN THE AFTERNOON WITH HIGHER CHANCES OVER THE RIDGES AND IN
DEEPER MOISTURE NEAR THE EASTERN BORDER LATE IN THE DAY. RAISED
FORECAST HIGHS A LITTLE WITH SOME SUNSHINE AND THE WARMING ALOFT.
SHOULD BE LESS OF A HEAVY RAIN THREAT...STILL A LOW SEVERE THREAT
BUT ALSO PROBABLY A BIT LESS THAN TODAY.
LONG TERM...AN UPPER LEVEL RIDGE BUILDING OVER THE WEST WILL
ALLOW FOR A DRIER NORTHERLY FLOW ALOFT OVER THE CWFA FOR THURSDAY
THROUGH SATURDAY. BEST CHC FOR TSTMS WILL BE OVER THE MTNS AND
FAR EASTERN PLAINS. OVER THE WEEKEND...THUNDERSTORMS WILL INCREASE
OVER THE MOUNTAINS ON SATURDAY...WITH THE FLOW ALOFT BECOMING
SOUTHWESTERLY AS THE RIDGE GETS SHIFTS TO THE SOUTH AND EAST.
SUNDAY AND MONDAY WILL BE MORE UNSETTLED AS AN UPPER LEVEL TROUGH
IS PROGGED TO MOVE OVER NORTHERN COLORADO. THERE WILL BE A BETTER
CHANCE OF SHOWERS AND TSTMS AT THAT TIME WITH SLIGHTLY COOLER
TEMPERATURES BY MONDAY AS WELL.
AVIATION...SCATTERED THUNDERSTORMS EXPECTED IN THE DENVER AREA
MAINLY BETWEEN 21Z AND 00Z...STILL A LOW THREAT THIS EVENING. MAIN
IMPACT WILL BE VARIABLE WIND GUSTS TO 30 KNOTS. VFR PREVAILING BUT
LOCALIZED IFR CONDITIONS UNDER THE HEAVIEST CELLS. COULD BE ENOUGH
STORMS TO REQUIRE INSTRUMENT APPROACHES TO KDEN AT TIMES...MAINLY
THROUGH 00Z. LESS THUNDERSTORM ACTIVITY EXPECTED WEDNESDAY WITH
LITTLE IMPACT.
HYDROLOGY...SLOW MOVING THUNDERSTORMS WITH HEAVY RAIN IN THE
STRONGER CELLS THIS AFTERNOON AND EVENING. RAINFALL OF UP TO 1
INCH IN AN HOUR IS POSSIBLE IN THE MOUNTAINS...AND 1.5 INCHES IN
AN HOUR ON THE PLAINS. THERE IS A LOW THREAT OF FLASH
FLOODING...MAINLY FOR THE FOOTHILLS BURN AREAS THIS AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1154 AM MDT MON AUG 12 2013
.UPDATE...
&&
.SHORT TERM...ONLY MINOR CHANGES TO THE FORECAST. HEALTHY CROP OF
DIURNAL CONVECTION HAS FORMED OVER THE MOUNTAINS AND SHOULD
PROGRESS SLOWLY EASTWARD. STORM MOTIONS HAVE BEEN SLOW
INITIALLY...BUT SHOULD PICK UP A BIT AS WE WILL LIKELY HAVE AN
ORGANIZED OUTFLOW BOUNDARY HEADED EAST IN A COUPLE OF HOURS. STILL
SOME HEAVY RAIN POTENTIAL...BUT BETWEEN THE LIMITED CAPE OF AROUND
500 J/KG NEAR THE MOUNTAINS AND EXPECTED STORM MOVEMENT I DO NOT
EXPECT MUCH OF A FLOODING THREAT OUTSIDE OF THE BURN AREAS. FOR
THE BURN AREAS...AGAIN STORM STRENGTH AND MOISTURE ARE LIMITED BUT
WE WILL HAVE TO WATCH OUT FOR THE SLOW MOTIONS. MAIN THREAT SHOULD
BE THROUGH ABOUT 4 PM WITH THE STRONGEST ACTIVITY FURTHER EAST
AFTER THAT. I DID TWEAK POPS DOWN ON THE PLAINS FOR THIS AFTERNOON
EXPECTING THAT THE STORMS WILL BE SLOW TO PROGRESS EASTWARD. COULD
BE SOME DEVELOPMENT OUT THERE AS WELL BUT LIMITED UNTIL THIS
EVENING.
&&
.AVIATION...SCATTERED THUNDERSTORMS SHOULD PROGRESS EAST OFF THE
MOUNTAINS ACROSS THE DENVER AREA. ACTIVITY MOST LIKELY BETWEEN 21Z
AND 00Z THOUGH THERE WILL STILL BE SOME AROUND THIS EVENING. MAIN
IMPACT SHOULD BE VARIABLE WINDS GUSTING TO AROUND 30 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 355 AM MDT MON AUG 12 2013/
SHORT TERM...WATER VAPOR LOOP INDICATED A MOISTURE PLUME SHIFTING
NORTHEAST ACROSS COLORADO EARLY THIS MORNING. AT THE SURFACE...A
WEAK SURGE HAD PUSH ACROSS MOST OF THE PLAINS WITH A SLIGHT
INCREASE IN LOW LEVEL MOISTURE. HOWEVER...THIS MOISTURE WAS QUITE
SHALLOW AS PRECIPITABLE WATER VALUES HAD BARELY BUDGED OVER THE
LAST 24 HOURS. OVERALL...THE WEATHER PATTERN REMAINS QUITE SIMILAR
TO YESTERDAY WITH THE UPPER LEVEL RIDGE CENTERED OVER THE STATE.
HOWEVER...ONE FEATURE THAT MAY COME INTO PLAY IS AN UPPER LEVEL
SPEED MAX MOVING ACROSS THE DESERT SOUTHWEST. THE FORECAST AREA
WILL BE IN THE LEFT EXIT REGION OF THIS JET FROM THIS AFTERNOON
THROUGH TONIGHT. THERE WAS DEEP...PERSISTENT...BUT WEAK Q-G LIFT
NOTED IN MOST MODELS THROUGH TONIGHT. THIS SHOULD HELP INCREASE
CONVECTIVE COVERAGE A BIT FROM YESTERDAY. MEANWHILE...SHORT RANGE
MESOSCALE MODELS INCLUDING THE WRF AND HRRR SHOW THE TYPICAL START
TO CONVECTION ALONG THE FRONT RANGE MOUNTAINS AND FOOTHILLS BY
17Z-18Z...AND THEN SPREADING/DEVELOPING EASTWARD THROUGH THE
AFTERNOON HOURS. AT THIS POINT...SEE LITTLE REASON TO ARGUE WITH
THIS SCENARIO. THERE WILL BE A SLIGHT RISK OF ONE OR TWO STORMS
BRIEFLY REACHING SEVERE CRITERIA ON THE PLAINS WITH MARGINAL
HAIL/WIND.
WITH CONTINUED SYNOPTIC SCALE LIFT AND WEAK LOW LEVEL
SOUTHEASTERLY JET OVERNIGHT...WILL KEEP A CHANCE OF STORMS IN THE
FORECAST THROUGH TONIGHT.
LONG TERM...EASTERLY UPSLOPE SURFACE FLOW WILL MOVE OVER THE
PLAINS FROM A SHORTWAVE TROUGH DIVING SOUTH FROM THE DAKOTAS
ALOFT. COMBINE THIS WITH A FEW DISTURBANCES MOVING IN THE
WESTERLY FLOW ALOFT AND INCREASING UPPER AND MID-LEVEL MOISTURE
MOVING IN FROM THE SOUTHWEST WILL ALL COME TOGETHER TUESDAY AND
WEDNESDAY FOR COOLER AND WETTER DAYS. THE FOCUS FOR THE MOST
SIGNIFICANT WEATHER WILL BE EAST OF THE MOUNTAINS AS SLIGHTLY
DRIER AIR WILL BE FILTERING IN FROM THE WEST. STORM MOTIONS ARE
PROGGED TO BE SLOW...10 MPH OR LESS SO THUNDERSTORMS WITH HEAVY
RAINFALL WILL BE A CONCERN. BEST INSTABILITY WILL BE OUT TOWARDS
THE EASTERN STATE BORDER WITH HAIL AND STRONG WINDS THE THREAT.
ALL THE CONDITIONS WILL EXIST THROUGH THE BOTH DAYS TO HAVE AT
LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS LAST THROUGHOUT
THE NIGHTS. TEMPERATURES WILL BE AS MUCH AS 10 DEGREES COOLER THAN
TODAY WITH READINGS IN THE UPPER 70S TO LOWER 80S FOR THE PLAINS
AND 60S TO 70S FOR THE HIGH COUNTRY.
BEGINNING THURSDAY...THE FLATTENED UPPER RIDGE WILL BEGIN BUILDING
BACK NORTH THROUGH FRIDAY...STRETCHING FROM ARIZONA UP TO
MONTANA. THIS WILL PUT COLORADO UNDER NORTH-NORTHWEST FLOW ALOFT.
THE SHORTWAVE TROUGH MAY STILL HAVE AN AFFECT THURSDAY AND SOUTH
TO SOUTHEASTERLY SURFACE FLOW OVER THE FAR EASTERN PLAINS WILL
TRANSPORT SOME MOISTURE IN FOR SCATTERED STORM ACTIVITY OVER THE
MOUNTAINS AND A SLIGHT CHANCE FOR THE PLAINS. DRIER AIR WILL BE
SPREADING IN FROM THE WEST FRIDAY TO KEEP CHANCES FOR STORMS OVER
THE HIGH TERRAIN WITH ISOLATED COVERAGE. TEMPERATURES WILL BE
CLIMBING BACK TO AVERAGE AND POSSIBLY SLIGHTLY WARMER UNDER THE
BUILDING RIDGE.
ON SATURDAY...A TROUGH WILL MOVE ONSHORE OVER THE WEST COAST AND
START MOVING EAST. SATURDAY WILL BE ONE MORE WARM AND DRY DAY
BEFORE THE TROUGH DRAWS MOISTURE INTO THE AREA FOR SLIGHTLY WETTER
CONDITIONS SUNDAY. WILL HAVE TO FOLLOW THE PROGRESSION OF THE
MODELS FOR THIS TROUGH TO SEE HOW STRONG IT MAY BE. FOR NOW KEPT
TEMPERATURES THE SAME...BUT MAY NEED TO COOL THEM OR LATER
PERIODS.
AVIATION...WEAK SURFACE BOUNDARY THAT BARELY PUSHED THROUGH THE
FRONT RANGE AIRPORTS WILL KEEP LIGHT AND VARIABLE WINDS IN THE
FORECAST THROUGH 15Z-17Z. ONLY A SLIGHT CHANCE OF LIGHT/PATCHY
FOG DEVELOPING 12Z-14Z WITH MARGINAL T/TD SPREADS. THEN NORMAL
DIURNAL EASTERLIES WILL DEVELOP. STORM CHANCES WILL BE A LITTLE
HIGHER THAN YESTERDAY SO TEMPO VRB20G30-35KT WINDS AND TS OR -TSRA
WOULD BE WARRANTED IN THE FAVORED TIME FRAME FROM 20Z- 02Z. A
SLIGHT CHANCE OF STORMS LINGERING PAST 06Z. BRIEF MVFR CONDITIONS
WOULD BE POSSIBLE IF A STORM CORE PASSES OVERHEAD.
HYDROLOGY...PRECIPITABLE WATER VALUES AND TEMP PROFILES ARE
SIMILAR TO THOSE OBSERVED YESTERDAY...ALTHOUGH STORM MOTION WILL
LIKELY BE UNDER 10 MPH. STORMS THIS AFTERNOON AND EVENING WILL BE
CAPABLE OF PRODUCING 0.50 TO 1.0 INCH IN 30 MINUTES. THAT WOULD
POSE A RISK OF SOME FLOODING IF ONE OF THESE STRONGER STORMS MOVES
OVER A FOOTHILL BURN SCAR. THE STRONGEST STORMS ON THE PLAINS
COULD PRODUCE 1-2 INCHES IN AN HOUR WITH MINOR FLOODING. THREATS
ARE LOW ENOUGH AT THIS TIME TO PRECLUDE A FLASH FLOOD WATCH.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....KRIEDERMAN
AVIATION/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
355 AM MDT MON AUG 12 2013
.SHORT TERM...WATER VAPOR LOOP INDICATED A MOISTURE PLUME SHIFTING
NORTHEAST ACROSS COLORADO EARLY THIS MORNING. AT THE SURFACE...A
WEAK SURGE HAD PUSH ACROSS MOST OF THE PLAINS WITH A SLIGHT
INCREASE IN LOW LEVEL MOISTURE. HOWEVER...THIS MOISTURE WAS QUITE
SHALLOW AS PRECIPITABLE WATER VALUES HAD BARELY BUDGED OVER THE
LAST 24 HOURS. OVERALL...THE WEATHER PATTERN REMAINS QUITE SIMILAR
TO YESTERDAY WITH THE UPPER LEVEL RIDGE CENTERED OVER THE STATE.
HOWEVER...ONE FEATURE THAT MAY COME INTO PLAY IS AN UPPER LEVEL
SPEED MAX MOVING ACROSS THE DESERT SOUTHWEST. THE FORECAST AREA
WILL BE IN THE LEFT EXIT REGION OF THIS JET FROM THIS AFTERNOON
THROUGH TONIGHT. THERE WAS DEEP...PERSISTENT...BUT WEAK Q-G LIFT
NOTED IN MOST MODELS THROUGH TONIGHT. THIS SHOULD HELP INCREASE
CONVECTIVE COVERAGE A BIT FROM YESTERDAY. MEANWHILE...SHORT RANGE
MESOSCALE MODELS INCLUDING THE WRF AND HRRR SHOW THE TYPICAL START
TO CONVECTION ALONG THE FRONT RANGE MOUNTAINS AND FOOTHILLS BY
17Z-18Z...AND THEN SPREADING/DEVELOPING EASTWARD THROUGH THE
AFTERNOON HOURS. AT THIS POINT...SEE LITTLE REASON TO ARGUE WITH
THIS SCENARIO. THERE WILL BE A SLIGHT RISK OF ONE OR TWO STORMS
BRIEFLY REACHING SEVERE CRITERIA ON THE PLAINS WITH MARGINAL
HAIL/WIND.
WITH CONTINUED SYNOPTIC SCALE LIFT AND WEAK LOW LEVEL
SOUTHEASTERLY JET OVERNIGHT...WILL KEEP A CHANCE OF STORMS IN THE
FORECAST THROUGH TONIGHT.
.LONG TERM...EASTERLY UPSLOPE SURFACE FLOW WILL MOVE OVER THE
PLAINS FROM A SHORTWAVE TROUGH DIVING SOUTH FROM THE DAKOTAS
ALOFT. COMBINE THIS WITH A FEW DISTURBANCES MOVING IN THE
WESTERLY FLOW ALOFT AND INCREASING UPPER AND MID-LEVEL MOISTURE
MOVING IN FROM THE SOUTHWEST WILL ALL COME TOGETHER TUESDAY AND
WEDNESDAY FOR COOLER AND WETTER DAYS. THE FOCUS FOR THE MOST
SIGNIFICANT WEATHER WILL BE EAST OF THE MOUNTAINS AS SLIGHTLY
DRIER AIR WILL BE FILTERING IN FROM THE WEST. STORM MOTIONS ARE
PROGGED TO BE SLOW...10 MPH OR LESS SO THUNDERSTORMS WITH HEAVY
RAINFALL WILL BE A CONCERN. BEST INSTABILITY WILL BE OUT TOWARDS
THE EASTERN STATE BORDER WITH HAIL AND STRONG WINDS THE THREAT.
ALL THE CONDITIONS WILL EXIST THROUGH THE BOTH DAYS TO HAVE AT
LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS LAST THROUGHOUT
THE NIGHTS. TEMPERATURES WILL BE AS MUCH AS 10 DEGREES COOLER THAN
TODAY WITH READINGS IN THE UPPER 70S TO LOWER 80S FOR THE PLAINS
AND 60S TO 70S FOR THE HIGH COUNTRY.
BEGINNING THURSDAY...THE FLATTENED UPPER RIDGE WILL BEGIN BUILDING
BACK NORTH THROUGH FRIDAY...STRETCHING FROM ARIZONA UP TO
MONTANA. THIS WILL PUT COLORADO UNDER NORTH-NORTHWEST FLOW ALOFT.
THE SHORTWAVE TROUGH MAY STILL HAVE AN AFFECT THURSDAY AND SOUTH
TO SOUTHEASTERLY SURFACE FLOW OVER THE FAR EASTERN PLAINS WILL
TRANSPORT SOME MOISTURE IN FOR SCATTERED STORM ACTIVITY OVER THE
MOUNTAINS AND A SLIGHT CHANCE FOR THE PLAINS. DRIER AIR WILL BE
SPREADING IN FROM THE WEST FRIDAY TO KEEP CHANCES FOR STORMS OVER
THE HIGH TERRAIN WITH ISOLATED COVERAGE. TEMPERATURES WILL BE
CLIMBING BACK TO AVERAGE AND POSSIBLY SLIGHTLY WARMER UNDER THE
BUILDING RIDGE.
ON SATURDAY...A TROUGH WILL MOVE ONSHORE OVER THE WEST COAST AND
START MOVING EAST. SATURDAY WILL BE ONE MORE WARM AND DRY DAY
BEFORE THE TROUGH DRAWS MOISTURE INTO THE AREA FOR SLIGHTLY WETTER
CONDITIONS SUNDAY. WILL HAVE TO FOLLOW THE PROGRESSION OF THE
MODELS FOR THIS TROUGH TO SEE HOW STRONG IT MAY BE. FOR NOW KEPT
TEMPERATURES THE SAME...BUT MAY NEED TO COOL THEM OR LATER
PERIODS.
&&
.AVIATION...WEAK SURFACE BOUNDARY THAT BARELY PUSHED THROUGH THE
FRONT RANGE AIRPORTS WILL KEEP LIGHT AND VARIABLE WINDS IN THE
FORECAST THROUGH 15Z-17Z. ONLY A SLIGHT CHANCE OF LIGHT/PATCHY
FOG DEVELOPING 12Z-14Z WITH MARGINAL T/TD SPREADS. THEN NORMAL
DIURNAL EASTERLIES WILL DEVELOP. STORM CHANCES WILL BE A LITTLE
HIGHER THAN YESTERDAY SO TEMPO VRB20G30-35KT WINDS AND TS OR -TSRA
WOULD BE WARRANTED IN THE FAVORED TIME FRAME FROM 20Z- 02Z. A
SLIGHT CHANCE OF STORMS LINGERING PAST 06Z. BRIEF MVFR CONDITIONS
WOULD BE POSSIBLE IF A STORM CORE PASSES OVERHEAD.
&&
.HYDROLOGY...PRECIPITABLE WATER VALUES AND TEMP PROFILES ARE
SIMILAR TO THOSE OBSERVED YESTERDAY...ALTHOUGH STORM MOTION WILL
LIKELY BE UNDER 10 MPH. STORMS THIS AFTERNOON AND EVENING WILL BE
CAPABLE OF PRODUCING 0.50 TO 1.0 INCH IN 30 MINUTES. THAT WOULD
POSE A RISK OF SOME FLOODING IF ONE OF THESE STRONGER STORMS MOVES
OVER A FOOTHILL BURN SCAR. THE STRONGEST STORMS ON THE PLAINS
COULD PRODUCE 1-2 INCHES IN AN HOUR WITH MINOR FLOODING. THREATS
ARE LOW ENOUGH AT THIS TIME TO PRECLUDE A FLASH FLOOD WATCH.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....KRIEDERMAN
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
352 AM MDT MON AUG 12 2013
.SHORT TERM...WATER VAPOR LOOP INDICATED A MOISTURE PLUME SHIFTING
NORTHEAST ACROSS COLORADO EARLY THIS MORNING. AT THE SURFACE...A
WEAK SURGE HAD PUSH ACROSS MOST OF THE PLAINS WITH A SLIGHT
INCREASE IN LOW LEVEL MOISTURE. HOWEVER...THIS MOISTURE WAS QUITE
SHALLOW AS PRECIPITABLE WATER VALUES HAD BARELY BUDGED OVER THE
LAST 24 HOURS. OVERALL...THE WEATHER PATTERN REMAINS QUITE SIMILAR
TO YESTERDAY WITH THE UPPER LEVEL RIDGE CENTERED OVER THE STATE.
HOWEVER...ONE FEATURE THAT MAY COME INTO PLAY IS AN UPPER LEVEL
SPEED MAX MOVING ACROSS THE DESERT SOUTHWEST. THE FORECAST AREA
WILL BE IN THE LEFT EXIT REGION OF THIS JET FROM THIS AFTERNOON
THROUGH TONIGHT. THERE WAS DEEP...PERSISTENT...BUT WEAK Q-G LIFT
NOTED IN MOST MODELS THROUGH TONIGHT. THIS SHOULD HELP INCREASE
CONVECTIVE COVERAGE A BIT FROM YESTERDAY. MEANWHILE...SHORT RANGE
MESOSCALE MODELS INCLUDING THE WRF AND HRRR SHOW THE TYPICAL START
TO CONVECTION ALONG THE FRONT RANGE MOUNTAINS AND FOOTHILLS BY
17Z-18Z...AND THEN SPREADING/DEVELOPING EASTWARD THROUGH THE
AFTERNOON HOURS. AT THIS POINT...SEE LITTLE REASON TO ARGUE WITH
THIS SCENARIO. THERE WILL BE A SLIGHT RISK OF ONE OR TWO STORMS
BRIEFLY REACHING SEVERE CRITERIA ON THE PLAINS WITH MARGINAL
HAIL/WIND.
WITH CONTINUED SYNOPTIC SCALE LIFT AND WEAK LOW LEVEL
SOUTHEASTERLY JET OVERNIGHT...WILL KEEP A CHANCE OF STORMS IN THE
FORECAST THROUGH TONIGHT.
.LONG TERM...EASTERLY UPSLOPE SURFACE FLOW WILL MOVE OVER THE
PLAINS FROM A SHORTWAVE TROUGH DIVING SOUTH FROM THE DAKOTAS
ALOFT. COMBINE THIS WITH A FEW DISTURBANCES MOVING IN THE
WESTERLY FLOW ALOFT AND INCREASING UPPER AND MID-LEVEL MOISTURE
MOVING IN FROM THE SOUTHWEST WILL ALL COME TOGETHER TUESDAY AND
WEDNESDAY FOR COOLER AND WETTER DAYS. THE FOCUS FOR THE MOST
SIGNIFICANT WEATHER WILL BE EAST OF THE MOUNTAINS AS SLIGHTLY
DRIER AIR WILL BE FILTERING IN FROM THE WEST. STORM MOTIONS ARE
PROGGED TO BE SLOW...10 MPH OR LESS SO THUNDERSTORMS WITH HEAVY
RAINFALL WILL BE A CONCERN. BEST INSTABILITY WILL BE OUT TOWARDS
THE EASTERN STATE BORDER WITH HAIL AND STRONG WINDS THE THREAT.
ALL THE CONDITIONS WILL EXIST THROUGH THE BOTH DAYS TO HAVE AT
LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS LAST THROUGHOUT
THE NIGHTS. TEMPERATURES WILL BE AS MUCH AS 10 DEGREES COOLER THAN
TODAY WITH READINGS IN THE UPPER 70S TO LOWER 80S FOR THE PLAINS
AND 60S TO 70S FOR THE HIGH COUNTRY.
BEGINNING THURSDAY...THE FLATTENED UPPER RIDGE WILL BEGIN BUILDING
BACK NORTH THROUGH FRIDAY...STRETCHING FROM ARIZONA UP TO
MONTANA. THIS WILL PUT COLORADO UNDER NORTH-NORTHWEST FLOW ALOFT.
THE SHORTWAVE TROUGH MAY STILL HAVE AN AFFECT THURSDAY AND SOUTH
TO SOUTHEASTERLY SURFACE FLOW OVER THE FAR EASTERN PLAINS WILL
TRANSPORT SOME MOISTURE IN FOR SCATTERED STORM ACTIVITY OVER THE
MOUNTAINS AND A SLIGHT CHANCE FOR THE PLAINS. DRIER AIR WILL BE
SPREADING IN FROM THE WEST FRIDAY TO KEEP CHANCES FOR STORMS OVER
THE HIGH TERRAIN WITH ISOLATED COVERAGE. TEMPERATURES WILL BE
CLIMBING BACK TO AVERAGE AND POSSIBLY SLIGHTLY WARMER UNDER THE
BUILDING RIDGE.
ON SATURDAY...A TROUGH WILL MOVE ONSHORE OVER THE WEST COAST AND
START MOVING EAST. SATURDAY WILL BE ONE MORE WARM AND DRY DAY
BEFORE THE TROUGH DRAWS MOISTURE INTO THE AREA FOR SLIGHTLY WETTER
CONDITIONS SUNDAY. WILL HAVE TO FOLLOW THE PROGRESSION OF THE
MODELS FOR THIS TROUGH TO SEE HOW STRONG IT MAY BE. FOR NOW KEPT
TEMPERATURES THE SAME...BUT MAY NEED TO COOL THEM OR LATER
PERIODS.
&&
.AVIATION...WEAK SURFACE BOUNDARY THAT BARELY PUSHED THROUGH THE
FRONT RANGE AIRPORTS WILL KEEP LIGHT AND VARIABLE WINDS IN THE
FORECAST THROUGH 15Z-17Z. THEN NORMAL DIURNAL EASTERLIES WILL
DEVELOP. STORM CHANCES WILL BE A LITTLE HIGHER THAN YESTERDAY SO
TEMPO VRB20G30-35KT WINDS AND TS OR -TSRA WOULD BE WARRANTED IN
THE FAVORED TIME FRAME FROM 20Z-02Z. A SLIGHT CHANCE OF STORMS
LINGERING PAST 06Z. BRIEF MVFR CONDITIONS WOULD BE POSSIBLE IF A
STORM CORE PASSES OVERHEAD.
&&
.HYDROLOGY...PRECIPITABLE WATER VALUES AND TEMP PROFILES ARE
SIMILAR TO THOSE OBSERVED YESTERDAY...ALTHOUGH STORM MOTION WILL
LIKELY BE UNDER 10 MPH. STORMS THIS AFTERNOON AND EVENING WILL BE
CAPABLE OF PRODUCING 0.50 TO 1.0 INCH IN 30 MINUTES. THAT WOULD
POSE A RISK OF SOME FLOODING IF ONE OF THESE STRONGER STORMS MOVES
OVER A FOOTHILL BURN SCAR. THE STRONGEST STORMS ON THE PLAINS
COULD PRODUCE 1-2 INCHES IN AN HOUR WITH MINOR FLOODING. THREATS
ARE LOW ENOUGH AT THIS TIME TO PRECLUDE A FLASH FLOOD WATCH.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....KRIEDERMAN
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
740 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BRING SHOWERS AND EMBEDDED
THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL THROUGH THIS EVENING.
DRY AND SEASONABLE WEATHER RETURNS WEDNESDAY AND CONTINUES INTO
THIS WEEKEND.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
*** SHOWERS AND EMBEDDED THUNDERSTORMS MAY BRING LOCALLY HEAVY
RAINFALL/POOR DRAINAGE STREET FLOODING THIS EVENING ***
730 PM UPDATE...STRONG LOW-LEVEL WIND SHEAR IS DOING WHAT IT CAN
TO ORGANIZE MEAGER INSTABILITY THIS EVENING. KENX RADAR WAS
ESTIMATING MAX WINDS ABOUT 35 KT IN THE LOWEST 3000 FT AGL. BASED
ON SURFACE OBS...PROBABLY NOT EVEN SEEING THAT AT THE GROUND. BEST
ESTIMATE IS FOR MAX 20 KT GUSTS WITH THAT LINE AS IT MOVES EAST
INTO WESTERN MA AND NORTHERN CT.
MAIN CHANGES THIS EVENING WERE TO ADJUST TIMING OF POPS. 13/21Z
HRRR AND RAP LOOKED TO BE HANDLING THE TIMING WELL. EXPECTING LINE
TO DISSIPATE TO A LARGE EXTENT AS IT MOVES EAST AND ENTERS A LESS
FAVORABLE ENVIRONMENT. ALSO ADJUSTED TEMPERATURES AND DEW POINTS
TO BRING THEM IN LINE WITH OBSERVED TRENDS.
PREVIOUS DISCUSSION...
4 PM UPDATE...MUCH OF THE RAIN HAS DISSIPATED OR MOVED OFFSHORE
IN THIS AREA. EXCEPTIONS TO THIS ARE THE CAPE AND ISLANDS WHERE
STORMS ARE MOVING ACROSS NOW. THE STRONGEST OF THESE STORMS REMAIN
WELL SOUTH OF SOUTHERN NEW ENGLAND AND THE OUTER COASTAL WATERS.
THAT SAID...THIS HAS BEEN WELL FORECAST BY THE HRRR MODEL. THE
HRRR IS ALSO ACCURATELY FORECASTING ADDITIONAL SHOWERS AND
THUNDERSTORMS IN NEW YORK STATE JUST AHEAD OF THE COLD FRONT.
THESE ARE FORECAST NOT TO MOVE INTO OUR AREA UNTIL CLOSE TO
00Z...AT WHICH POINT INSTABILITY IS LIKELY TO BE MORE LIMITED THAN
IT ALREADY IS. HOWEVER...THERE ARE STARTING TO BE SOME INDICATIONS
OF CLEARING ACROSS NEW YORK STATE AND EVEN A BIT INTO THE
CONNECTICUT VALLEY IN MASS AND CONNECTICUT. IF THIS CLEARING
CONTINUES...IT MAY PRODUCE ENOUGH INSTABILITY TO SUSTAIN THESE
STORMS.
IF THE STORMS SUSTAIN THEMSELVES...THERE IS POTENTIAL FOR LOCALLY
HEAVY RAINFALL AND POSSIBLY URBAN AND POOR DRAINAGE FLOODING. IN
ADDITION...THE ENVIRONMENT IS THE SAME HIGH SHEAR...LOW CAPE
ENVIRONMENT WE HAVE BEEN IN MUCH OF THE SUMMER. THEREFORE...THERE IS
A POTENTIAL FOR STRONG WINDS WITH THE STRONGEST STORMS.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
TONIGHT...LINGERING SHOWERS SHOULD COME TO AN END SHORTLY AFTER
MIDNIGHT IF NOT BEFORE. THEN CLEARING FROM WEST TO EAST AS THE COLD
FRONT MOVES THROUGH AND DRIER AIR STARTS MOVING IN. TEMPERATURES
OVERNIGHT WILL REMAIN FAIRLY MILD WHILE THE DRY AIR MOVES IN.
WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE STARTS BUILDING INTO
THE REGION. A REASONABLY STRONG LOW LEVEL JET AND DECENT MIXING
WILL RESULT IN GUSTY WINDS DURING THE DAY WHICH WILL PRECLUDE SEA
BREEZES FROM DEVELOPING. OTHERWISE...QUIET WEATHER EXPECTED WITH
BELOW NORMAL TEMPERATURES MORE REMINISCENT OF SEPTEMBER THAN OF MID
AUGUST.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* QUIET...SEASONABLE WEATHER THROUGH THIS WEEKEND
* POSSIBILITY OF SOME RAIN EARLY NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
13/12Z GUIDANCE CONTINUES TO DECENT OVERALL SYNOPTIC AGREEMENT
THROUGH MUCH OF THIS PERIOD.
13/00Z LONG RANGE GUIDANCE CONTINUES TO SHOW QUITE GOOD AGREEMENT
THROUGH MUCH OF THE LONG TERM. INITIAL WEAK MID-LEVEL CUTOFF IS
PROGGED TO MOVE INTO THE CANADIAN MARITIMES...WITH ANOTHER MID-
LEVEL CUTOFF MOVING FROM HUDSON BAY TO SOUTHEAST CANADA TOWARD
THE END OF THIS WEEK. THIS SETS UP A PATTERN WITH A BROAD MID-
LEVEL TROUGH OVER SOUTHEAST CANADA...WITH A WEAKER SOUTHERN
BRANCH OF THE JET STREAM CONVERGING NEAR THE MARITIMES. THE END
RESULT SHOULD BE PERSISTENT RIDGING NEAR OR OVER SOUTHERN NEW
ENGLAND THROUGH MUCH OF THE EXTENDED FORECAST. STAYED CLOSE TO THE
CONSENSUS SOLUTION...UNTIL SOME OF THE FINER DETAILS CAN BE BETTER
RESOLVED.
THURSDAY INTO
AS A SECOND CUTOFF DIVES S FROM HUDSON BAY
IN THE PERSISTENT BROAD TROF OVER ERN CANADA AND THE NORTHEAST
CONUS. HOWEVER...THE LONGWAVE TROF AND THIS SECOND CUTOFF LOOK TO
HAVE LITTLE EFFECT ON THE REGION AS STRONG RIDGING ALONG THE
SOUTHERN HALF OF THE CONUS COMBINES WITH RIDGING IN THE ATLANTIC
TO YIELD SUBSIDENCE AND BROAD SFC HIGH PRES OVER THE NORTHEAST.
GIVEN THERE IS GOOD AGREEMENT BETWEEN BOTH OPERATIONAL MODELS AND
THEIR COUNTERPART ENSEMBLES...HAVE REASONABLY HIGH CONFIDENCE THAT
THIS HIGH PRES WILL YIELD A MOSTLY DRY FORECAST THROUGH EARLY NEXT
WEEK. GIVEN THIS...WILL USE A GFS/ECMWF BLEND AS A BASELINE FOR
THIS FORECAST UPDATE.
TEMPERATURES SHOULD SLOWLY RISE THROUGH THIS PORTION OF THE
FORECAST...BUT REMAIN SEASONABLE. COMFORTABLE HUMIDITY LEVELS
THROUGH FRIDAY...WILL SLOWLY INCREASE THIS WEEKEND INTO EARLY NEXT
WEEK. THERE IS SOME QUESTION AS TO HOW CLOSE A LOW PRESSURE WILL
GET TO OUR REGION EARLY NEXT WEEK. AT THIS JUNCTURE...THINKING IT
WILL REMAIN WELL TO OUR SOUTH...SO KEPT THE FORECAST DRY.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE
WEDNESDAY AND WEDNESDAY NIGHT.
TONIGHT...HIGH PROBABILITY OF A LINE OF SHOWERS AND ISOLATED
THUNDERSTORMS MOVING INTO WESTERN ZONES THOUGH 03Z. OTHERWISE...
LIKELY TO SEE SOME LINGERING LOW CLOUDS AND FOG PATCHES PERSIST AT
SOME /ESPECIALLY EASTERN/ TERMINALS INTO THE OVERNIGHT HOURS.
AREAL COVERAGE OF LOW CLOUDS AND FOG PATCHES STILL UNCERTAIN.
LIGHT ONSHORE EAST WINDS ALONG THE EAST COAST SHOULD WEAKEN...THEN
SHIFT WEST LATER TONIGHT.
WEDNESDAY...ANY LEFTOVER MVFR-IFR CONDITIONS IN SCATTERED LOW
CLOUDS/FOG PATCHES WILL IMPROVE TO VFR NOT LONG AFTER SUNRISE.
OTHERWISE...VFR CONDITIONS.
WEDNESDAY NIGHT...VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING. MAY SEE BOUNCING BETWEEN VFR AND LOWER CATEGORIES WITH
RAIN THIS EVENING. MORE LIKELY RAIN DOES NOT HOLD TOGETHER EAST
OF KORH AT THIS POINT. WILL CONTINUE TO MONITOR. HIGH CONFIDENCE
VFR WEDNESDAY.
KBDL TERMINAL...MODERATE CONFIDENCE IN TRENDS AND TIMING THIS
EVENING. HIGH CONFIDENCE VFR WEDNESDAY.
OUTLOOK...THURSDAY THROUGH SUNDAY...
HIGH CONFIDENCE VFR. LOW CONFIDENCE FOR IFR IN PATCHY FOG AND LOW
CLOUDS LATE THURSDAY NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN WATERS THIS
AFTERNOON WITH ANOTHER ROUND OF ISOLATED TO SCATTERED STORMS LATE
THIS EVENING. THESE STORMS WILL LIMIT VISIBILITIES. EXPECT
CLEARING LATE TONIGHT WITH FAIRLY QUIET WEATHER WEDNESDAY AND
WEDNESDAY NIGHT. THERE IS POTENTIAL FOR 5 FOOT SEAS AND WESTERLY
WINDS GUSTING TO 25 KTS ON THE OUTER WATERS. WITH THE NICE BOATING
WEATHER EXPECTED...HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE OUTER
WATERS FOR WEDNESDAY AND WEDNESDAY NIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. WINDS WILL SHIFT
DIRECTION AS A HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND AND
THE WATERS BUT WILL REMAIN BELOW 20 KTS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 5 AM EDT THURSDAY
FOR ANZ250-254>256.
&&
$$
SYNOPSIS...BELK
NEAR TERM...BELK/RLG
SHORT TERM...RLG
LONG TERM...BELK
AVIATION...BELK/RLG
MARINE...BELK/RLG
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1053 AM EDT MON AUG 12 2013
.SYNOPSIS...
WEAKENING HIGH PRESSURE SHIFTS FARTHER OFFSHORE WITH A STALLED
FRONTAL BOUNDARY SOUTH OF THE REGION THROUGH TUESDAY MORNING. A
COLD FRONT MOVES ACROSS LATE TUESDAY. BEHIND THE COLD FRONT...A
LARGE AREA OF HIGH PRESSURE OVER THE MIDWEST WILL BUILD SOUTH AND
EAST ACROSS THE OHIO VALLEY AND MID ATLANTIC STATES THROUGH THE
END OF THE WEEK. THE HIGH IS THEN FORECAST TO REMAIN OVER THE
NORTHEAST NEXT WEEKEND AS A FRONTAL BOUNDARY ALONG THE MID
ATLANTIC COAST LIFTS SLOWLY NORTHWARD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST WATER VAPOR AND RUC 500 HPA ANALYSIS SHOW A WEAK 500 HPA
SHORTWAVE PASSING JUST TO THE S OF LONG ISLAND...AS THIS EXITS TO
THE EAST BY EARLY AFTERNOON...IT SHOULD BASICALLY BRING THE THREAT
OF SHOWERS TO AN END THROUGH AT LEAST MID AFTERNOON. NOTING THAT
THE AREA OF CONVECTION NEAR LAKE ERIE IS WEAKENING...AND LATEST
GUDIANCE SUGGEST LITTLE IF ANY PRECIPITATION THIS AFTERNOON...HAVE
REDUCED POPS FOR THIS AFTERNOON TO SLIGHT CHANCE...AND HAVE TAKEN
OUT AREAL COVERAGE WORDING...AS THERE IS NOW GREAT DOUBT WHETHER
ANY CONVECTION WILL FORM. IF CURRENT RADAR/SATELLITE/MODEL TRENDS
HOLD...COULD SEE PULLING POPS COMPLETELY WITH MIDDAY UPDATE.
MADE SOME MNOR CHANGES TO THE SKY GRID...BUT STILL APPEAR ON TRACK
TO GO FROM MOSTLY CLOUDY TO AT LESAT PARTLY SUNNY THIS AFTERNOON.
BASED ON LATEST VISIBILE TRENDS WESTERN AREAS MAY END UP MOSTLY
SUNNY - BUT NOT QUITE CONFIDENT ENOUGH IN THAT TO FORECAST AT THIS
TIME...BUT WILL REFELCT IN MIDDAY UPDATE IF TRENDS HOLD.
FOR MAX TEMPS TODAY...CONTINUED WITH BLEND OF MAV AND MET GUIDANCE.
THIS YIELDS HIGHS IN THE MOSTLY IN THE LOWER 80S...EXCEPT MID 70S
TO AROUND 80 COASTAL AREAS AND MID 80S IN THE NYC METRO HEAT
ISLAND AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
A STEADY PERSISTENT PATTERN DEVELOPS GOING INTO TUESDAY WITH A
STALLED FRONTAL BOUNDARY TO THE SOUTH BUT WITH PERIODIC EPISODES
OF WARM AIR ADVECTION ALOFT AHEAD OF IT. THESE WILL BE ASSOCIATED
WITH SMALL AMPLITUDE SHORTWAVE...WHICH WILL ALSO BRING SOME
POSITIVE VORTICITY ADVECTION. ALL IN ALL...THIS IS POINTING TO AN
UNSETTLED WEATHER SCENARIO THAT WILL CONVEY SHOWERS AND
THUNDERSTORMS POPPING UP AND DEVELOPING NEAR AND WITHIN THE AREA.
FOR THE LOWS TONIGHT...USED A BLEND OF THE WARMER NAM12/MET
GUIDANCE TAKING INTO ACCOUNT THE EXTRA CLOUDS. COLD POOL CONTINUES
TO STRENGTHEN TONIGHT GOING INTO TUESDAY MORNING.
THIS WILL SET UP A HIGHER COVERAGE OF CONVECTION ON TUESDAY WITH
CAPE VALUES ALSO REACHING AROUND THE 1000-1500 J/KG
RANGE...HIGHEST ACROSS THE INTERIOR AWAY FROM THE ONSHORE MARINE
INFLUENCE. SOME THUNDERSTORMS COULD PRODUCE GUSTY WINDS AND HAIL
AS BULK SHEAR 0-6 KM OF MAINLY 30-35 KT WILL BE PRESENT. RIGHT
REAR QUAD JET WILL ALSO BE NEAR THE REGION AS WELL TO HELP WITH
FORCING. THIS WILL ALSO CONVEY THE HIGHEST LOW LEVEL CAPE IN
COMBINATION WITH DEEPEST COLD POOL ALOFT WITH STRONGER CYCLONIC
FLOW ALOFT.
FOR THE HIGHS TUESDAY...USED A BLEND OF MAV AND MET NUMBERS WITH
GREATER WEIGHT TOWARDS THE MAVS WHICH WERE WARMER. THE CONVECTION
IS NOT THOUGHT TO LAST THE WHOLE DAY AND WITH THE BREAKS...ENOUGH
DAYTIME WARMING IS EXPECTED TO GIVE SLIGHTLY WARMER TEMPERATURES.
THE COLD FRONT APPROACHES DURING THE DAY AND THEN MOVES ACROSS
DURING THE EVENING. CONVECTION WILL LOWER IN COVERAGE BY LATE
EVENING WITH MAINLY DRY CONDITIONS RETURNING FROM WEST TO EAST
OVERNIGHT ON A MORE NORTHERLY FLOW. AGAIN...GIVEN EXTRA
CLOUDS...WARMER MAV GUIDANCE WAS PREFERRED WITH GREATER WEIGHT FOR
TUESDAY NIGHT LOW TEMPS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
GLOBAL MODELS ARE ALL IN VERY GOOD AGREEMENT WITH TAKING THE
NORTHERN BRANCH UPPER TROF ACROSS EASTERN CANADA AND THE NE STATES
NORTH AND EAST THROUGH THE END OF THE WEEK...WITH GRADUALLY RISING
HEIGHTS. THE SOUTHERN BRANCH TROF GETS LEFT BEHIND E OF THE MS RIVER
VALLEY. THE LATTER OF WHICH ALSO SLOWLY FILLS AND LIFTS NORTH AND
EAST OVER THE WEEKEND.
AT THE SURFACE...A LARGE SPRAWLING HIGH OVER THE UPPER MIDWEST ON
WED BUILDS EAST ACROSS THE OHIO VALLEY AND MID ATLANTIC STATES
THROUGH THE END OF THE WEEK. A STALLED OUT FRONTAL BOUNDARY ALONG
THE SE AND MID ATLANTIC COAST BEGINS TO SLOWLY LIFT NORTHWARD
THROUGH THE WEEKEND...AS HIGH PRESSURE BUILDS EAST ACROSS NEW
ENGLAND. THUS...AT THIS TIME...THE FORECAST IS MAINLY DRY WITH A LOW
CHANCE FOR SHOWERS NEXT WEEKEND DUE TO THE OFFSHORE FRONTAL BOUNDARY
APPROACHING FROM THE SOUTH. THE 00Z GFS AND ECMWF BOTH SUPPORT A DRY
FORECAST NEXT WEEKEND. NEED TO SEE SOME MORE RUN TO RUN CONSISTENCY
BEFORE REMOVING RAIN CHANCES COMPLETELY.
IN ADDITION...THE AIR MASS WILL BE COOLER THAN NORMAL BY ABOUT 3 TO 5
DEGREES. HIGHS ARE FORECAST TO BE IN THE UPPER 70S TO AROUND
80...WITH LOWS GRADUALLY MODERATING FROM THE 50S WED MORNING. DEW
POINTS WILL BE MAINLY IN THE 50S.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
GENERALLY VFR CONDITIONS TODAY.
LIGHT SHOWERS WILL PUSH EAST...EXITING THE AREA BY 18Z. EXPECTING
MAINLY DRY CONDITIONS THIS AFTERNOON THOUGH CANNOT RULE OUT A STRAY
LATE AFTN SHOWER. NOT ENOUGH CONFIDENCE AT THIS TIME TO INCLUDE IN TAFS.
SCT-BKN MID AND HIGH LEVEL CLOUDS WILL SCATTER OUT BY LATER THIS
AFTN.
LIGHT AND VARIABLE WINDS WILL TURN SOUTHERLY FOR THE AFTN. PLEASE
SEE COMMENTS CONCERNING SEA BREEZE DEVELOPMENT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: SEA BREEZE DEVELOPMENT COULD BE +/- 1 HOUR.
KLGA FCSTER COMMENTS: LOW CONFIDENCE ON SEA BREEZE DEVELOPMENT AND
TIMING. COULD BE +1 HR.
KEWR FCSTER COMMENTS: LOW CONFIDENCE ON WIND DIRECTION THROUGH
20Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LOW CONFIDENCE ON WIND DIRECTION THROUGH
20Z.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: SEA BREEZE TIMING COULD BE +/- 1 HOUR.
.OUTLOOK FOR 12Z TUE THROUGH THU...
.TUE...SCT SHOWERS/TSTMS WITH BRIEF MVFR OR LOWER CONDS.
.WED-FRI...VFR.
&&
.MARINE...
MINOR CHANGES THIS UPDATE TO REFELCT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. CHANCE FOR ANY CONVECTION THIS
AFTERNOON IS DIMINISHING.
TRANQUIL CONDITIONS WITH A WEAK PRESSURE GRADIENT IN PLACE ACROSS
THE WATERS THROUGH TUESDAY NIGHT. GUSTS WILL REACH UP TO NEAR 20
KT TUESDAY AFTERNOON AND NIGHT SURROUNDING NEAR THE TIMES OF THE
FRONTAL PASSAGE. SCA GUSTS WILL BE POSSIBLE POST COLD FRONT GOING
INTO WEDNESDAY MORNING BUT FORECAST IS BELOW THIS CRITERION AT THE
MOMENT.
A POST-FRONTAL NW FLOW ON WED WILL FEATURE WIND GUSTS RIGHT AROUND
20 KT...WITH SEAS WELL BELOW 5 FT. HIGH PRESSURE THEN BUILDS ACROSS
THE WATERS THU AND FRI WITH WINDS 10 KT OR LESS AND LIGHT SEAS.
&&
.HYDROLOGY...
ISOLD-SCT SHRA/TSRA THROUGH TONIGHT IS EXPECTED TO PRODUCE MAINLY
RAIN AMOUNTS OF BELOW A QUARTER OF AN INCH.
GENERALLY EXPECT BETWEEN MAINLY 4/10 AND 1 INCH OF BASIN AVG QPF
WITH THE COLD FRONT TUE/TUE NIGHT WITH POSSIBLY HIGHER AMOUNTS. ANY
FLOOD POTENTIAL LOOKS TO BE RESTRICTED TO MAINLY POOR DRAINAGE
AND OTHER MINOR FLOODING.
DRY WEATHER THEN PREVAILS THROUGH THE END OF THE WORK WEEK.
&&
.EQUIPMENT...
THE NOAA ALL HAZARDS WEATHER RADIO TRANSMITTER IN NEW YORK CITY
IS OFF THE AIR...AND UNAVAILABLE UNTIL FURTHER NOTICE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...MALOIT/JM
SHORT TERM...JM
LONG TERM...DW
AVIATION...SEARS
MARINE...MALOIT/JM/DW
HYDROLOGY...JM/DW
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1000 AM EDT Mon Aug 12 2013
.UPDATE...
Per discussion below, a hot day with only isolated showers and
thunderstorms this afternoon. This morning`s KTAE sounding shows
PWAT down to 1.59". With the increased insolation and the stacked
high pressure overhead, temps will max out in the upper 90s inland
areas with a few locations possibly reaching the century mark. Heat
indices will be around 105 and possibly briefly peak at 108 in and
around Valdosta and the Suwannee River Valley.
&&
.PREVIOUS DISCUSSION...
329 AM EDT Mon Aug 12 2013
.NEAR TERM [Today and Tonight]...
With a firmly established upper level ridge in place for one more
day and PWATS expected to continue to drop as deep layer drier air
advects in from the east, conditions appear favorable for what
should be the hottest day of the summer season thus far! For
example, we are forecasting a High temp of 101 at VLD today (which
would eclipse the earlier 100 from June 12), 99 at TLH (which would
exceed the 98 on June 12 and 13, and a 99 at ABY (which would be a
whopping 4 degrees higher than the 95 which also occurred on June 12
and 13). For reference, it does NOT appear (at this time) that we
will break any record high temps today at these sites which are
listed as follows:
TLH: 100 set in 2011
ABY: 100 set in 1957
VLD: 101 set in 2011
Despite the very hot temps, we do expect dewpoints to mix out into
the upper 60s to lower 70s, which should keep Heat Indices just
below Heat Advisory Levels (108-113). The lone exception could be
around VLD and the Suwannee River Valley where a VERY few 108s and
109s could be possible. However, this area appears too small to
warrant an Advisory at this time, so will leave it out for now, and
let the day shift make any adjustments if needed. PoPs should be
quite low, generally in the 15-20% range, with only a few 30s
possible across parts of SE AL. This will also set the stage for a
very warm and humid night across the CWA tonight, with lows
generally in the mid to upper 70s from the interior to near the
coast.
&&
.SHORT TERM [Tuesday through Wednesday]...
GOES Blended TPW product and objective precipitable water analysis
from the RAP model shows a plume of above normal PWATs (2.1-2.2")
situated just to the west of our area over the Lower Mississippi
River Valley. This deeper moisture is expected to advect into our
area in the next 24 hours as the upper level ridge centered over
north Florida weakens. At the same time, we will see a weak front
approach from the north, and a weakness (or low-amplitude trough)
develop in the upper level ridge just west of our forecast area.
These ingredients suggest that rain will be on the increase
Tuesday and Wednesday - probably focused in the northwest half of
our area on Tuesday, and then spreading further into our area on
Wednesday. The high PWATs will be accompanied by very weak flow,
with projected storm motions at or below 5 knots (per NAM/GFS).
At least localized heavy rainfall is likely when you juxtapose
deep moisture and very slow storm motions. Therefore, we added
heavy rainfall wording to the forecast on Tuesday and Wednesday in
areas that have "likely" PoPs (>55%). For high temperatures we
kept a NW-SE gradient with the warmest conditions in the SE part
of our area. Low temperatures were kept fairly warm as there
should be an increase in cloud cover.
&&
.LONG TERM [Wednesday Night through Sunday]...
Not much change with the forecast pattern for later this week into
next weekend, as broad low amplitude trough becomes established
over the central Gulf Coast/southeast states. An attendant surface
front will likewise slide swd into the region. Combination of
these features suggests return to wetter than normal pattern,
which will also likely cap high temperatures a bit below normal
each day. We could see some heavy rainfall at times, with WPC
painting 3-3.5" totals on average over the tri-state region.
&&
.AVIATION [through 12 UTC Tuesday]...
Expect VFR conditions to prevail through the period with just few
to sct CU and CI the rest of the overnight hours and during the
day today. Although an isolated TSTM cannot be ruled out, the
minimal PoPs and coverage should preclude any mention of
convection at this time.
&&
.MARINE...
A relatively weak pressure pattern should persist despite the
approach of a weak front from the north. This should keep winds
around 10 knots or less, with seas 2 feet or less. Thunderstorm
activity over the waters should increase by Wednesday.
&&
.FIRE WEATHER...
Red flag conditions are not expected over the next several days,
although today will feature some of the lower RHs in many days.
&&
.HYDROLOGY...
Area river levels continue to slowly decrease or remain steady and
this should be the story of the next couple days. As a rainy
pattern re-emerges by mid-week, we should start to see flows on at
least a few of the rivers begin to increase again by late week or
into the weekend. It is too early to say which rivers may be
affected, as heavy rainfall could be somewhat localized.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 99 74 95 74 91 / 20 10 40 20 60
Panama City 93 79 90 78 88 / 20 20 40 20 50
Dothan 97 75 91 73 88 / 20 20 70 30 70
Albany 99 75 93 74 90 / 20 20 60 30 70
Valdosta 101 72 96 73 93 / 20 10 30 20 60
Cross City 97 72 94 74 93 / 10 10 20 10 30
Apalachicola 91 78 90 78 88 / 10 10 20 20 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...Barry
NEAR TERM...Gould
SHORT TERM...Lamers
LONG TERM...Evans
AVIATION...Gould
MARINE...Lamers
FIRE WEATHER...Gould
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
329 AM EDT Mon Aug 12 2013
.NEAR TERM [Today and Tonight]...
With a firmly established upper level ridge in place for one more
day and PWATS expected to continue to drop as deep layer drier air
advects in from the east, conditions appear favorable for what
should be the hottest day of the summer season thus far! For
example, we are forecasting a High temp of 101 at VLD today (which
would eclipse the earlier 100 from June 12), 99 at TLH (which would
exceed the 98 on June 12 and 13, and a 99 at ABY (which would be a
whopping 4 degrees higher than the 95 which also occurred on June 12
and 13). For reference, it does NOT appear (at this time) that we
will break any record high temps today at these sites which are
listed as follows:
TLH: 100 set in 2011
ABY: 100 set in 1957
VLD: 101 would tie the 101 from the xmACIS database (year unknown)
Despite the very hot temps, we do expect dewpoints to mix out into
the upper 60s to lower 70s, which should keep Heat Indices just
below Heat Advisory Levels (108-113). The lone exception could be
around VLD and the Suwannee River Valley where a VERY few 108s and
109s could be possible. However, this area appears too small to
warrant an Advisory at this time, so will leave it out for now, and
let the day shift make any adjustments if needed. PoPs should be
quite low, generally in the 15-20% range, with only a few 30s
possible across parts of SE AL. This will also set the stage for a
very warm and humid night across the CWA tonight, with lows
generally in the mid to upper 70s from the interior to near the
coast.
&&
.SHORT TERM [Tuesday through Wednesday]...
GOES Blended TPW product and objective precipitable water analysis
from the RAP model shows a plume of above normal PWATs (2.1-2.2")
situated just to the west of our area over the Lower Mississippi
River Valley. This deeper moisture is expected to advect into our
area in the next 24 hours as the upper level ridge centered over
north Florida weakens. At the same time, we will see a weak front
approach from the north, and a weakness (or low-amplitude trough)
develop in the upper level ridge just west of our forecast area.
These ingredients suggest that rain will be on the increase
Tuesday and Wednesday - probably focused in the northwest half of
our area on Tuesday, and then spreading further into our area on
Wednesday. The high PWATs will be accompanied by very weak flow,
with projected storm motions at or below 5 knots (per NAM/GFS).
At least localized heavy rainfall is likely when you juxtapose
deep moisture and very slow storm motions. Therefore, we added
heavy rainfall wording to the forecast on Tuesday and Wednesday in
areas that have "likely" PoPs (>55%). For high temperatures we
kept a NW-SE gradient with the warmest conditions in the SE part
of our area. Low temperatures were kept fairly warm as there
should be an increase in cloud cover.
&&
.LONG TERM [Wednesday Night through Sunday]...
Not much change with the forecast pattern for later this week into
next weekend, as broad low amplitude trough becomes established
over the central Gulf Coast/southeast states. An attendant surface
front will likewise slide swd into the region. Combination of
these features suggests return to wetter than normal pattern,
which will also likely cap high temperatures a bit below normal
each day. We could see some heavy rainfall at times, with WPC
painting 3-3.5" totals on average over the tri-state region.
&&
.AVIATION [through 12 UTC Tuesday]...
Expect VFR conditions to prevail through the period with just few
to sct CU and CI the rest of the overnight hours and during the
day today. Although an isolated TSTM cannot be ruled out, the
minimal PoPs and coverage should preclude any mention of
convection at this time.
&&
.MARINE...
A relatively weak pressure pattern should persist despite the
approach of a weak front from the north. This should keep winds
around 10 knots or less, with seas 2 feet or less. Thunderstorm
activity over the waters should increase by Wednesday.
&&
.FIRE WEATHER...
Red flag conditions are not expected over the next several days,
although today will feature some of the lower RHs in many days.
&&
.HYDROLOGY...
Area river levels continue to slowly decrease or remain steady and
this should be the story of the next couple days. As a rainy
pattern re-emerges by mid-week, we should start to see flows on at
least a few of the rivers begin to increase again by late week or
into the weekend. It is too early to say which rivers may be
affected, as heavy rainfall could be somewhat localized.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 99 74 95 74 91 / 20 10 40 20 60
Panama City 93 79 90 78 88 / 20 20 40 20 50
Dothan 97 75 91 73 88 / 20 20 70 30 70
Albany 99 75 93 74 90 / 20 20 60 30 70
Valdosta 101 72 96 73 93 / 20 10 30 20 60
Cross City 97 72 94 74 93 / 10 10 20 10 30
Apalachicola 91 78 90 78 88 / 10 10 20 20 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Lamers
LONG TERM...Evans
AVIATION...Gould
MARINE...Lamers
FIRE WEATHER...Gould
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
714 PM EDT TUE AUG 13 2013
.UPDATE...
COLD FRONT CURRENTLY ACROSS NORTHERN GA THIS EVENING. A FEW
SHOWERS HAVE DEVELOPED BEHIND THE BOUNDARY...BUT THEY HAVE BEEN
SHORT LIVED. STORMS ARE MORE NUMEROUS SOUTH OF THE METRO
AREA...WHERE ACTIVITY KEEPS MOVING IN FROM EASTERN AL. THE ATMOS
ACROSS PORTIONS OF CENTRAL AND SOUTHERN GA WILL REMAIN UNSTABLE
FOR THE NEXT FEW HOURS. CONVECTION SEEMS TO MOSTLY BE OUTFLOW
DRIVEN. DO EXPECT STORMS TO DIMINISH WITH THE LOSS OF
HEATING AND MOSTLY BE GONE BY MIDNIGHT. THE HRRR SUPPORTS THIS.
MAY HAVE TO DO ADDITIONAL UPDATES TO THE POPS ACROSS NORTHERN
GA...MAINLY AREAS NORTH OF THE FRONT...LATER TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 325 PM EDT TUE AUG 13 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
SHORT RANGE MODELS CONTINUE TO SHOW A COLD FRONT...CURRENTLY ACROSS
TN... SAGGING ACROSS NORTH GA TONIGHT AND STALLING ACROSS CENTRAL GA
WEDNESDAY AFTERNOON. REGIONAL RADARS SHOW SCATTERED SHOWERS AND
THUNDERSTORMS BEGINNING TO DEVELOP ACROSS THE FORECAST AREA AS AN
UPPER DISTURBANCE APPROACHES FROM THE WEST. EXPECT A WEAK SURFACE
TROUGH TO HELP PROVIDE A FOCUS ACROSS NORTH GA THIS AFTERNOON AND
RADAR TRENDS SUPPORT THAT...WITH A SCATTERED LINE OF CONVECTION
DEVELOPING FROM WEST OF ROME...EASTWARD TO JASPER AND CLEVELAND.
EXPECT THIS ACTIVITY TO SAG SOUTHWARD THROUGH THE LATE AFTERNOON AND
EVENING HOURS. ADDITIONAL SCATTERED TO NUMEROUS CONVECTION IS
DEVELOPING ACROSS PARTS OF CENTRAL GA WHERE THE GREATER
INSTABILITIES AND DEEPER MOISTURE ARE POOLED. THE HRRR MODEL
CLUSTERS MOST OF THE CONVECTIVE ACTIVITY ACROSS THE CENTRAL ZONES...
FROM AREAS AROUND COLUMBUS TO MACON TO MILLEDGEVILLE AND SOUTHWARD
DURING THE LATE AFTERNOON AND EVENING HOURS. THUNDERSTORM ACTIVITY
MAY PERSIST THROUGH MID EVENING BEFORE DIMINISHING TO MAINLY
SHOWERS. SCATTERED SHOWERS MAY PERSIST OVERNIGHT ALONG AND AHEAD OF
THE COLD FRONT... BUT ANY THUNDERSTORM ACTIVITY SHOULD BE VERY
ISOLATED AT BEST OVERNIGHT. THE MAIN THUNDERSTORM THREAT THROUGH THE
EVENING WILL CONTINUE TO BE LOCALLY HEAVY RAIN AND POSSIBLE BRIEF
FLOODING. HOWEVER... WITH 2500-3000 CAPE... CANNOT RULE OUT A PULSE
STRONG STORM PRODUCING WIND GUSTS TO 40-45 MPH AND POSSIBLY SOME
SMALL HAIL. MODELS AGREE ON DRIER AIR SPREADING IN BEHIND THE FRONT
ACROSS NORTH GA BY EARLY WEDNESDAY... SO WILL SHOW THE GREATER RAIN
CHANCES ACROSS CENTRAL GA ON WEDNESDAY...AND MAINLY ALONG AND SOUTH
OF A LA GRANGE TO WARRENTON LINE...WITH ONLY A LOW CHANCE IN THE
ATLANTA METRO AREA FOR WEDNESDAY AFTERNOON. LOCALLY HEAVY RAIN WILL
REMAIN A THREAT ACROSS CENTRAL GA WEDNESDAY AFTERNOON AS THE FRONT
PROVIDES A FOCUS FOR TRAINING CONVECTION. MODELS SHOW GENERALLY ONE
QUARTER TO ONE HALF INCH FROM COLUMBUS TO MACON AND SOUTHWARD ON
WEDNESDAY... BUT ISOLATED HIGHER AMOUNTS OF 1 TO 3 INCHES ARE
POSSIBLE. ALTHOUGH CANNOT RULE OUT A PULSE STRONG TO SEVERE STORM
ALONG OR SOUTH OF THE FRONT WEDNESDAY AFTERNOON... NOT EXPECTING
ANYTHING WIDESPREAD AND THE GREATER STRONG STORM THREAT SHOULD BE
JUST SOUTH OF THE FORECAST AREA WEDNESDAY AFTERNOON AND EVENING.
OTHERWISE... AS FOR TEMPS A MODEL BLEND THROUGH THE SHORT TERM
LOOKED REASONABLE.
39
LONG TERM /THURSDAY THROUGH TUESDAY/...
GUIDANCE CONTINUES TO POINT TO A WET EXTENDED PERIOD. AS THE FRONT
SAGS SOUTH OF THE AREA TROUGH THE SHORT TERM...SURFACE HIGH UNDER
CONFLUENT FLOW ALOFT WILL SLIP EAST AND ACROSS THE APPALACHIANS IN
A HYBRID DAMMING EVENT. THE QUESTION WILL BE HOW MUCH GULF
MOISTURE WILL INTERACT WITH THE DAMMING. FOR THURSDAY...WITH THE
STALLED FRONT AND ONSET OF HYBRID CAD...HPC AND SYNOPTIC MODELS
KEEP THE BEST PRECIP ACROSS CENTRAL GEORGIA...WITH A GOOD INCH OF
BASIN-AVERAGE QPF DURING THE DAY. THIS TREND CONTINUES INTO
FRIDAY. BESIDES THE PRECIP HOWEVER...THE BIGGEST SENSIBLE IMPACT
WILL BE TEMPS. CURRENT HIGH TEMPS FOR THURSDAY THROUGH SATURDAY DO
NOT BRING NORTH GEORGIA OUT OF THE 70S...AND REALLY ONLY INTO THE
MID 80S IN SOUTHERN ZONES. POSSIBLY A SLIGHT WARMING TREND BY A
DEGREE OR SO ON SUNDAY BUT THIS REMAINS TO BE SEEN. THESE FORECAST
MAX TEMPS ARE A GOOD 10 DEGREES COOLER THAN SEASONAL NORMALS...
THE KIND OF IMPACTS NORMALLY SEEN WITH CLASSICAL CAD RATHER THAN
HYBRID CAD.
00Z ECMWF CONTINUES TO TAKE THE TROPICAL WAVE /CURRENTLY IN THE
CARIBBEAN/ FURTHER WEST TOWARD THE YUCATAN...WHILE GFS AND
CANADIAN BRING IT INTO THE GULF AND CLOSE TO THE COAST FRIDAY
NIGHT. FOR WHAT ITS WORTH...THE CANADIAN IS STRONGER AND FURTHER
WEST WITH THE SURFACE LOW THAN THE GFS...WHICH WOULD POSSIBLY
INDICATE SEVERE POTENTIAL ON SATURDAY...BUT IT IS A BIT OF AN
OUTLIER THERE. ECMWF IS DRIEST WHILE GFS/CMC ARE WETTER
SOLUTIONS. HPC NOT GOING NEARLY AS HIGH AS THE GFS BUT EVEN
SO...WITH THE PROLONGED WET PERIOD ACROSS ESPECIALLY CENTRAL
GEORGIA FROM THE SHORT TERM FRONT...THERE IS SOME CONCERN ABOUT
THE RAINFALL PILING UP. HAVE NOT DONE A COMPLETE DIAGNOSIS TO
DETERMINE IF THE THURSDAY-FRIDAY RAIN WOULD QUALIFY AS A PRE
/PREDECESSOR RAINFALL EVENT/ BUT IN ANY CASE THE 7-DAY QPF TOTAL
FROM HPC ARE UPWARDS OF 6 INCHES ACROSS PORTIONS OF CENTRAL
GEORGIA. THIS BEING BASIN-AVERAGE...IMPLYING THAT SOME AREAS
COULD GET SUBSTANTIALLY MORE /AND OF COURSE SOME AREAS
SUBSTANTIALLY LESS/. ALL INTERESTS SHOULD STAY TUNED TO LATEST
FORECASTS AS THIS IS REFINED OVER THE NEXT FEW DAYS.
SO OVERALL...REALLY MADE ONLY MINOR CHANGES TO PREVIOUS EXTENDED
FORECAST. REFINED AND ADDED SOME DETAIL TO DAYS 4 AND 5 ESPECIALLY
WITH TEMPS WINDS AND DEWPOINTS /VERY LITTLE IF ANY CHANGE TO
POPS/ AND MADE SOME MINOR ADJUSTMENTS TO HIGH TEMPS THROUGH THE
REST OF THE PERIOD TO REFLECT THE PROLONGED COOL SPELL.
TDP
&&
.AVIATION...
00Z UPDATE...
CONVECTION WILL LINGER AT THE SOUTHERN TERMINAL SITES THIS
EVENING. A COLD FRONT WILL TRY AND PUSH SOUTH ACROSS THE NORTHERN
TERMINAL SITES OVERNIGHT...BRINGING IN A DRIER AIRMASS. STORMS
SHOULD REMAIN MAINLY SOUTH OF ATL TOMORROW...AS THE FRONTAL
BOUNDARY PUSHES SOUTH. MODELS ARE NOT PROGGING LOW CIGS
OVERNIGHT...BUT MAY HAVE TO RE- EXAMINE THE POTENTIAL IF ATL GETS
PRECIP.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON OVERNIGHT CIGS. HIGH CONFIDENCE REMAINING
ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 69 88 68 78 / 30 40 20 30
ATLANTA 70 86 69 79 / 30 30 20 50
BLAIRSVILLE 64 81 64 76 / 20 20 20 30
CARTERSVILLE 68 86 64 82 / 20 20 20 30
COLUMBUS 73 87 71 84 / 30 60 40 80
GAINESVILLE 69 85 68 76 / 20 20 20 30
MACON 72 89 71 82 / 40 60 50 80
ROME 68 89 63 83 / 20 20 10 30
PEACHTREE CITY 70 86 66 79 / 30 40 20 50
VIDALIA 74 88 71 84 / 50 60 60 80
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE/AVIATION...LISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
155 AM EDT MON AUG 12 2013
.PREV DISCUSSION... /ISSUED 731 PM EDT SUN AUG 11 2013/
UPDATE...
HIGH PRESSURE IS SITUATED ACROSS THE FLORIDA PANHANDLE THIS
EVENING. A LEE TROUGH IS DEVELOPED ALONG THE TAIL END OF THE
APPALACHIANS. CONVECTION REMAINS ACROSS THE NORTHERN CWFA THIS
EVENING. ADDITIONAL ACTIVITY HAS FORMED ACROSS CENTRAL/SOUTHERN TN
ALONG AN OLD OUTFLOW BOUNDARY.
LATEST RUNS OF THE HRRR SHOW THE ACTIVITY OVER TN DIMINISHING WITH
THE LOSS OF HEATING. IN ADDITION...THE STORMS OVER NORTHERN GA
SHOULD BEGIN TO DIMINISH WITH SUNSET. HAVE RE-ADJUSTED POPS TO
REFLECT THE LATEST TRENDS. ALSO MADE SOME TWEAKS TO THE HOURLY
TEMP/DEW GRIDS.
NLISTEMAA
PREV DISCUSSION... /ISSUED 350 PM EDT SUN AUG 11 2013/
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
SHORT RANGE MODELS SHOW LITTLE CHANGE IN THE OVERALL PATTERN THROUGH
THE SHORT TERM... WITH AN ACTIVE WESTERLY FLOW ALOFT PERSISTING.
THIS WILL HELP HOLD A WEAK FRONTAL BOUNDARY NORTH OF THE STATE AND
ACROSS THE TN VALLEY... ALL SUGGESTING THE GREATEST RAIN CHANCES
WILL REMAIN ACROSS NORTH GA AND AREAS NORTHWARD THIS AFTERNOON...
EVENING AND AGAIN ON MONDAY.
REGIONAL RADARS SHOW SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
ONGOING ACROSS FAR NORTH GA THIS AFTERNOON... AND THIS ACTIVITY WILL
PERSIST THROUGH MID EVENING BEFORE DISSIPATING WITH LOSS OF DAYTIME
HEATING. REDEVELOPMENT ALONG OUTFLOWS COULD ALLOW A FEW STORMS TO
PUSH DOWN INTO THE ATLANTA METRO AREA LATER THIS AFTERNOON OR
EVENING... BUT OVERALL TRENDS SUGGEST MOST CONVECTIVE ACTIVITY WILL
REMAIN JUST NORTH OF ATLANTA THROUGH THE EVENING. THIS COULD CHANGE
SLIGHTLY ON MONDAY AS INCREASING UPPER SUPPORT SHOULD HELP SPREAD
CONVECTION FURTHER SOUTH MONDAY AFTERNOON/EVENING. WILL CONTINUE TO
SHOW THE GREATER RAIN CHANCES ACROSS NORTH GA ON MONDAY... BUT AMPLE
MOISTURE /1.8+PW`S/ AND MODERATE INSTABILITIES /2500-3000 CAPE/ WITH
GREATER UPPER SUPPORT SUGGEST SCATTERED STORMS COULD DEVELOP JUST
ABOUT ANYWHERE MONDAY AFTERNOON. ALTHOUGH CANNOT RULE OUT AN
ISOLATED PULSE SEVERE STORM DURING MAX HEATING EACH DAY... THE MAIN
STORM THREAT CONTINUES TO BE LOCALLY HEAVY RAIN AND BRIEF FLOODING
AS STORMS WILL BE SLOW MOVING WITH A TENDENCY TO TRAIN FROM WEST TO
EAST ACROSS THE SAME AREAS. WIDESPREAD RAINFALL TOTALS FROM THIS
AFTERNOON THROUGH MONDAY AFTERNOON SHOULD BE GENERALLY AN INCH OR
LESS ACROSS NORTH GA...WITH SOME ISOLATED HIGHER AMOUNTS OF 2-3
INCHES LIKELY. EXPECT GENERALLY A QUARTER INCH OR LESS ELSEWHERE.
AS FOR TEMPS... LEANED TOWARD A BLEND BETWEEN PERSISTENCE AND THE
SLIGHTLY WARMER MAV THROUGH THE SHORT TERM.
39
LONG TERM /TUESDAY THROUGH SUNDAY/...
LITTLE CHANGE IN LONG TERM PATTERN. ZONAL FLOW CONTINUES INTO THE
BEGINNING OF THE EXTENDED FORECAST BUT GRADUALLY TRANSITIONS TO AN
UPPER TROUGH BY WED/THU. THE CWA REMAINS IN A MOIST AIR MASS WITH
WEAK IMPULSES IN THE UPPER FLOW. MODELS PERSISTENT IN SHOWING
A LITTLE DRIER AIR PUSHING INTO NORTH GA TOWARD THE END OF THE
WEEK WITH A WEDGE LIKE PATTERN SETTING UP. THIS WILL DEPEND UPON HOW
FAR SOUTH THE SURFACE BOUNDARY SINKS THOROUGH THE STATE. WILL CONTINUE
WITH PERSISTENCE AND KEEP POPS MENTIONED THROUGH DAY 7...WITH SOME
LOWERING OF POPS ACROSS THE NORTH BY THE END OF THE FORECAST. IF
SURFACE BOUNDARY PUSHES INTO CENTRAL GA AND THE EASTERLY FLOW SETS
UP...TEMPERATURES BY LATE WEEK SHOULD BE SEVERAL DEGREES COOLER
THAN SEASONAL NORMS.
01
&&
.AVIATION...
06Z UPDATE...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. DIURNAL CONVECTION
EXPECTED AGAIN THIS AFTERNOON AND EARLY EVENING. WINDS WILL REMAIN
WESTERLY...GENERALLY 5-8KT THROUGH THE DAY...AND LESS THAN 5 KT OVERNIGHT.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 72 89 70 / 50 30 60 30
ATLANTA 88 72 87 71 / 50 30 60 30
BLAIRSVILLE 83 68 81 64 / 60 50 60 30
CARTERSVILLE 87 70 86 69 / 60 40 60 30
COLUMBUS 92 74 91 73 / 40 30 60 30
GAINESVILLE 87 71 85 70 / 50 40 60 30
MACON 93 71 91 71 / 40 30 50 30
ROME 88 71 88 69 / 70 50 60 30
PEACHTREE CITY 88 70 87 70 / 50 30 60 30
VIDALIA 95 75 93 73 / 30 20 40 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....16
AVIATION...31
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1254 PM CDT MON AUG 12 2013
.DISCUSSION...
1135 AM CDT
FOR LATE MORNING UPDATE...
LITTLE/NO CHANGE TO GOING FORECAST...EXCEPT TO TWEAK CHANCE POP
COVERAGE AT MIDDAY BASED ON CURRENT RADAR/SATELLITE TRENDS AND COLD
FRONT POSITION. SPEAKING OF THE COLD FRONT...16Z SFC ANALYSIS
INDICATED IT WAS ROUGHLY FROM A WEAK LOW PRESSURE WAVE NEAR
MILWAUKEE...WEST TO NEAR JANESVILLE WI...THEN SOUTHWEST TO NEAR
SAVANNA AND MOLINE IL.
REGIONAL RADAR MOSAIC DEPICTS SCATTERED SHRA/TSRA OVER SOUTHERN LAKE
MICHIGAN AND SOUTHWEST LOWER MICHIGAN...ASSOCIATED WITH MOISTURE
TRANSPORT AND CONVERGENCE ON THE NOSE OF WEAKENING WESTERLY LOW
LEVEL JET AND WEAK SHORT WAVE NOTED IN VAPOR IMAGERY CURRENTLY
CROSSING THE LAKE EASTBOUND. OTHERWISE ONLY A FEW SHORT-LIVED
ISOLATED SHRA HAVE BEEN NOTED DURING THE MORNING HOURS MAINLY NEAR
THE SURFACE FRONT ACROSS FAR EAST/SOUTHEAST IOWA. EXPECTATION IS
THAT THIS WILL CHANGE OVER THE NEXT FEW HOURS HOWEVER...AS WEAK COLD
FRONT SLOWLY PUSHES SOUTHEAST ACROSS NORTHERN IL AND SOUTHERN LAKE
MICHIGAN DURING INCREASINGLY FAVORABLE TIMING OF DIURNAL
INSTABILITY. LOW LEVEL WARM SECTOR SOUTH OF THE COLD FRONTAL
BOUNDARY CHARACTERIZED BY LOW 80S TEMP/MID 60S DEW POINT CONDITIONS
WITH SOME WARMING STILL TO OCCUR ESPECIALLY ACROSS THE SOUTHEASTERN
PARTS OF THE CWA WHERE MORE SUNSHINE IS OCCURRING. CURRENT SPC/RAP
MESOANALYSIS INDICATES 500-1000 J/KG MLCAPE DEVELOPING IN THOSE
AREAS...AND EXTRAPOLATION FROM 12Z DVN RAOB AND FORECAST SOUNDINGS
FROM BOTH THE 12Z WRF-NAM/MOST RECENT 15Z RAP INDICATE 1000-1500
J/KG AVAILABLE DURING THE AFTERNOON HOURS...THOUGH THIN CIRRUS COVER
MAY NEGATIVELY AFFECT THIS A BIT. AIDING THE DESTABILIZATION OF THE
LOWER LEVELS WILL BE LARGER SCALE HEIGHT FALLS ACROSS THE UPPER
MIDWEST OCCURRING IN ASSOCIATION WITH A COUPLE OF SHORT WAVES
PIVOTING SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND ANOTHER
DIGGING INTO THE UPPER MIDWEST FROM SOUTHERN MANITOBA. HOWEVER...THE
STRONGEST LARGE SCALE ASCENT AS WELL AS STRONGER MID/UPPER LEVEL
WINDS AND DEEP LAYER BULK SHEAR WILL GENERALLY REMAIN OFF TO THE
NORTH/NORTHEAST OF THE CWA THROUGH THE AFTERNOON.
THUS IT APPEARS THAT SHRA/TSRA WILL GRADUALLY DEVELOP AND INCREASE
IN COVERAGE ALONG/AHEAD OF THE WEAK COLD FRONT IS IT MOVES SOUTHEAST
ACROSS THE AREA THIS AFTERNOON (AND EARLY THIS EVENING). A FEW
STORMS MAY BECOME STRONG ACROSS THE SOUTHEAST CWA LATER THIS
AFTERNOON...PRESENTING PRIMARILY A 50-60 MPH WIND GUST THREAT. WHILE
NOT OUTLOOKED FOR SEVERE...SPC DOES HAVE OUR EAST/SOUTHEAST CWA
INCLUDED IN THE 5 PERCENT DAY 1 WIND RISK.
RATZER
//PREV DISCUSSION...
316 AM CDT
THE FORECAST FOCUSES ON SHRA/TSRA TRENDS TODAY FOLLOWED BY BELOW
NORMAL TEMPS AS A STRONG HIGH PRESSURE AREA BUILDS IN BEHIND AN
APPROACHING COLD FRONT. EARLY MORNING WATER VAPOR IMAGERY SHOWS A
BROAD UPPER TROUGH OVER EASTERN CANADA...THE UPPER MIDWEST...THE
GREAT LAKES...AND NORTHERN NEW ENGLAND WITH ITS CLOSED CENTER OVER
JAMES BAY. A CORRIDOR OF RIDGING EXTENDS FROM NEW MEXICO INTO
SOUTHERN ALBERTA WITH A MUCH SMALLER CLOSED UPPER LOW OVER NORTHERN
ALBERTA. ANOTHER CLOSED UPPER LOW IS SPINNING NORTHWARD UP THE
WESTERN FLANK OF THE RIDGE FROM THE WASHING TO TO BRITISH COLUMBIA
COAST. THE LOCAL AREA IS ON THE SOUTHERN PERIPHERY OF THE BROAD
EASTERN TROUGH AND AT THE JUNCTION OF A FEED OF MOISTURE FROM THE
WEST-SOUTHWEST AND SHORTWAVE ENERGY FROM THE WEST-NORTHWEST. AT THE
SURFACE...HIGH PRESSURE STRETCHES ALONG THE OHIO VALLEY WHILE
TROUGHING STRETCHES FROM SOUTHERN QUEBEC ACROSS LAKE SUPERIOR AND
INTO CENTRAL WISCONSIN AND IOWA. SURFACE OBS SUGGEST A CLOSED LOW
OVER FAR NORTHERN WISCONSIN OR LAKE SUPERIOR WITH A COOL FRONTAL
BOUNDARY STRETCHING FROM THIS LOW SOUTHWEST TO JUST NORTH OF THE
TWIN CITIES TO EXTREME SW MINNESOTA AT 08Z.
TODAY AND TONIGHT...SHRA/TSRA POTENTIAL WILL BE A CHALLENGE TODAY.
CLUSTERS OF SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE EASTWARD
ACROSS FAR SOUTHERN WISCONSIN COINCIDENT WITH A SHARP LOW/MID LEVEL
THERMAL GRADIENT WITH ASCENT BEING AIDED BY MODEST BUT STILL FOCUSED
LOW LEVEL JET. VAD WIND PROFILES DO SHOW THE BEST CONVERGENCE
ASSOCIATED WITH THIS PRECIP WITH LESSER CONVERGENCE TO THE
SOUTHWEST ACROSS CENTRAL AND NORTHEAST IOWA WHERE CONVECTION HAS
STRUGGLED TO CONTINUE. THE BAROCLINIC ZONE IS EXPECTED TO START TO
SAG SOUTHWARD INTO FAR NORTHERN ILLINOIS OVER THE NEXT FEW HOURS
SUGGESTING THAT THERE MAY BE AT LEAST SOME SMALL INCREASE IN
SHRA/TSRA COVERAGE ACROSS THE NORTHERN CWA BUT THE LOW LEVEL JET
WILL START TO WANE SO ANY NEW ACTIVITY MAY BE SHORT LIVED. THE
AFOREMENTIONED COLD FRONT WILL BE WORKING SOUTHEASTWARD THROUGH
THE MORNING AND SHOULD REACH THE FAR NORTHWEST CWA BY LATE
MORNING. WITH THE LOW LEVEL JET WEAKENING DURING THE MORNING
PRECIP ACTIVITY LOOKS TO WANE WITH THE FRONT ITSELF NEEDING TO
TAKE OVER AS THE MAIN FORCING MECHANISM FOR NEW DEVELOPMENT.
ABUNDANT MID AND HIGH CLOUD COVER CONTINUES TO STREAM OVER THE
REGION WITH THICKER CLOUDS APPROACHING FROM THE PRECIP ACTIVITY
OVER IOWA. THIS WILL BE KEY IN DETERMINING HOW MUCH INSTABILITY
DEVELOPS AND WHERE IT DOES SO. TIMING OF THE FRONT WILL ALSO
DETERMINE HOW MUCH OF THE AREA WILL SEE A SHRA/TSRA THREAT THROUGH
THE DAY. NEAR TERM GUIDANCE SHOWS SOME DISCREPANCIES WITH THE
SPEED OF THE FRONT BUT OVERALL PREFER A SLOWER APPROACH GIVEN THE
FAIRLY UNIDIRECTIONAL STEERING FLOW AND THE PRESENCE OF THE
CURRENT CONVECTION. THIS THINKING WOULD BRING THE FRONT THROUGH
THE CHICAGO AREA AND POINTS WEST DURING MIDDAY OR EARLY AFTERNOON.
THIS LINE OF THINKING ALSO SUPPORTS THAT THE BEST THUNDER THREAT
WILL BE ACROSS THE SOUTHERN HALF OR SO OF THE AREA AS HEATING
INCREASES AND DESTABILIZATION COMMENCES. IT ALSO APPEARS THAT
THERE WILL BE SOME LARGER SCALE ASCENT PROVIDED BY A WEAK COUPLING
OF BRANCHES OF THE UPPER JET THIS AFTERNOON. WITH THIS IN MIND
WILL CONTINUE TO FOCUS THE GREATEST AFTERNOON POPS FROM NEAR GARY
SOUTHWEST TO PONTIAC AND POINTS SOUTH BUT NEW DEVELOPMENT MAY
INITIATE JUST TO THE NORTH OF THIS LINE ACROSS THE CHICAGO METRO
AND POINTS WEST ALONG INTERSTATE 80...ESPECIALLY IF THE FRONT IS A
BIT SLOWER. IN ADDITION...THERE DOES LOOK TO BE SOME INSTABILITY
BEHIND THE FRONT AND SOME SIGNS OF POSSIBLE ENHANCED CONVERGENCE
ALONG THE LAKESHORE AS WINDS TURN NORTHERLY WHICH COULD PROVIDE
SOME FOCUS FOR CONVECTION AS WELL. PROVIDED THAT THE EXPECTED
HEATING OCCURS THEN AREAS AHEAD OF THE FRONT WILL LIKELY SEE
1500-2000 J/KG OF CAPE THIS AFTERNOON. DEEP LAYER SHEAR WILL BE ON
THE ORDER OF ABOUT 30 KT. THIS WILL SUPPORT A SEVERE HAIL AND WIND
THREAT FROM THE BEST ORGANIZED STORMS ACROSS THE SOUTHERN HALF OF
THE AREA. OVERALL COVERAGE OF STORMS MAY ONLY BE SCATTERED WITH
CLOUD COVER BEING A LIMITATION SO WILL TOP POPS OUT IN THE HIGH
CHANCE CATEGORY. THE FRONT WILL BE SLOW TO EXIT TO THE SOUTH SO
SOUTHERN AREAS WILL SEE A CONTINUED SHRA/TSRA CHANCE ACROSS THE
FAR SOUTH THIS EVENING. HIGHS TODAY SHOULD RANGE FROM AROUND 80
NORTH TO THE MID 80S SOUTH.
TUESDAY THROUGH SUNDAY...STRONG HIGH PRESSURE WILL BE SPREADING
SOUTHWARD INTO THE MID AND UPPER MISSISSIPPI RIVER VALLEY TUESDAY
RESULTING IN NORTHERLY LOW LEVEL WINDS ACROSS THE CWA. THE BROAD
UPPER LEVEL TROUGH WILL HAVE SHARPENED UP WITH A TROUGH AXIS
DROPPING SOUTHEAST ACROSS THE AREA LATER IN THE DAY.
ACCORDINGLY...MUCH COOLER AIR WILL BE SPILLING INTO THE
AREA...ESPECIALLY FOLLOWING THE PASSAGE OF THE EMBEDDED TROUGH AXIS.
EXPECT H85 TEMPS TO TUMBLE FROM A PEAK OF AROUND +16C THIS AFTERNOON
TO AROUND +8C BY TUESDAY EVENING. EXPECT TUESDAY TO BE DRY DESPITE
THE PASSAGE OF THE TROUGH...GIVEN THAT THE ATMOSPHERE WILL BE
NOTICEABLY DRIER...THOUGH LOW LEVEL LAPSE RATES DO LOOK TO BE QUITE
SHARP...BUT THEY ARE SOMEWHAT SHALLOW. HIGHS WILL RANGE FROM THE
LOWER 70S WITHIN SEVERAL MILES OF LAKE MICHIGAN TO THE MID 70S
FURTHER INLAND. THE HIGH WILL CONTINUE TO PUSH SOUTH AND PARK ITSELF
OVER THE LOCAL AREA BY LATE WEDNESDAY. AN UPPER TROUGH WILL
GRADUALLY AMPLIFY AS RIDGING SHARPENS OVER THE WESTERN U.S. THROUGH
THE END OF THE WEEK. THE HIGH WILL SLOWLY WEAKEN AND THE AIRMASS
WILL SLOWLY MODIFY THROUGH THE END OF THE WEEK BUT MOST AREAS WILL
REMAIN IN THE 70S FOR HIGHS THROUGH FRIDAY...WITH MOST AREAS BEING
AROUND 80 FOR THE WEEKEND. AT THIS POINT THE REMAINDER OF THE WEEK
AND NEXT WEEKEND LOOK DRY BUT SOME MOISTURE MAY WORK ITS WAY INTO
THE EASTERN CWA TOWARD SUNDAY AS AN UPPER CIRCULATION EJECTS
NORTHWARD OVER THE MIDDLE OHIO VALLEY.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CHANCE OF SHRA/TSRA THROUGH MID/LATE AFTERNOON.
* WIND SHIFT TO NORTHEAST MID/LATE AFTERNOON.
* CHANCE OF MVFR CIGS OVERNIGHT/EARLY TUESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
SEVERAL FORECAST CONCERNS THIS PERIOD WITH THE TWO PRIMARY
CONCERNS TSRA POTENTIAL AND WIND SHIFT...BOTH THIS AFTERNOON.
A COLD FRONT EXTENDING FROM SOUTHEAST WI THROUGH NORTHWEST IL WILL
CONTINUE TO MOVE ACROSS THE TERMINALS THROUGH MID AFTERNOON. WINDS
HAVE SHIFTED LIGHT NORTHEASTERLY ACROSS SOUTHEAST WI AND WITH
PRECIP NOW DEVELOPING ALONG THE FRONT ACROSS FAR SOUTHEAST WI...
EXPECT THIS TO AID THE COLD FRONT/LAKE BREEZE TO ACCELERATE TO THE
SOUTHWEST THROUGH THE AFTERNOON. SO WHILE WINDS PROBABLY WILL TURN
NORTHWEST AT ORD/MDW...NOT SURE THE DURATION WILL BE TOO LONG AS
WINDS WILL LIKELY SHIFT NORTHEAST SOONER RATHER THAN LATER BUT
WILL NEED TO MONITOR TRENDS INTO THE AFTERNOON.
SHORT TERM/HI RES GUIDANCE HAS BEEN IN FAIR AGREEMENT WITH SHRA/
TSRA DEVELOPMENT EARLY THIS AFTERNOON ACROSS NORTHERN IL AND THEN
SHIFTING IT SLOWLY SOUTHEAST ACROSS THE TERMINALS THROUGH MID/LATE
AFTERNOON BUT CURRENT ACTIVITY HAS DEVELOPED A LITTLE FURTHER
NORTH AND SO FAR HAS REMAINED ISOLATED. MAINTAINED PREVIOUS VCTS
TIMING BUT EXPECT THIS WILL NEED TO BE TWEAKED...IN PARTICULAR...
PRECIP MAY LINGER A BIT LONGER THEN CURRENTLY ADVERTISED.
MVFR CLOUDS ACROSS SOUTHERN WI ESPECIALLY OVER SOUTHEAST WI COULD
DRIFT SOUTH BEHIND THE COLD FRONT/LAKE BREEZE BUT CONFIDENCE
REGARDING ANY POTENTIAL MVFR CIGS LATER THIS AFTERNOON...AND
THEIR DURATION IS LOW. A SECONDARY SURGE OF COLDER AIR ARRIVES
LATE TONIGHT AND AS THIS SPREADS ACROSS THE AREA...EXPECT SOME
LOWER CLOUD POTENTIAL...IN THE 1-2KFT RANGE BUT CIGS MAY BE
CONFINED CLOSER TO THE LAKE.
NORTH/NORTHEAST WINDS WILL DIMINISH THIS EVENING...POSSIBLY
TURNING BACK NORTHWESTERLY UNTIL THAT SURGE OF COLDER AIR ARRIVES
AND TURNS WINDS BACK NORTH/NORTHEAST WITH SPEEDS 10-12KTS. AFTER
SUNRISE...LOW LEVELS BEGIN TO MIX WITH GUSTS 18-20KTS POSSIBLE
THROUGH EARLY AFTERNOON. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM FOR SHRA/TSRA THROUGH MID/LATE AFTERNOON...LOW FOR DIRECT
IMPACTS AT ORD/MDW.
* HIGH FOR A WIND SHIFT TO THE NORTH/NORTHEAST MID/LATE
AFTERNOON...MEDIUM FOR TIMING.
* LOW FOR POTENTIAL MVFR CIGS OVERNIGHT/EARLY TUESDAY MORNING.
* HIGH FOR WIND SPEEDS/GUSTS OVERNIGHT/TUESDAY. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT THROUGH SUNDAY...VFR. DAILY LAKE BREEZE WIND SHIFTS
EXPECTED.
RC
&&
.MARINE...
304 AM CDT
A COLD FRONT WILL PUSH DOWN THE LAKE TODAY...WITH WINDS VEERING
FROM SOUTHWEST TO NORTH BEHIND THE FRONT. AS LARGE HIGH PRESSURE
BUILDS IN FROM THE NORTHWEST AND A COOL AIR MASS FILTERS INTO THE
REGION...WINDS WILL INCREASE TONIGHT...STRONGEST ON THE NORTH DUE
TO A SECONDARY EVEN STRONGER PUSH OF COLD AIR. SUSTAINED WINDS TO
20 KT WITH FREQUENT GUSTS INTO THE MID 20S KT RANGE ARE
EXPECTED...WITH EVEN A FEW 30 KT GUSTS POSSIBLE BEFORE WINDS BEGIN
TO EASE TOWARD DAYBREAK TUESDAY. THE SECONDARY PUSH OF COOL AIR
WILL ARRIVE ON THE SOUTH HALF OF THE LAKE DURING THE DAY ON
TUESDAY...RESULTING IN A SIMILAR INCREASE IN NORTHERLY WINDS TO 20
TO 25 KT WITH A FEW 30 KT GUSTS. WILL LIKELY NEED A SMALL CRAFT
ADVISORY FOR THE NEARSHORE WATERS STARTING SOME TIME TUESDAY
AFTERNOON AS WAVES BUILD UNTIL THEY SUBSIDE WEDNESDAY MORNING.
HIGH PRESSURE WILL ESTABLISH ITSELF OVER THE GREAT LAKES REGION
TUESDAY NIGHT...CAUSING WINDS TO DIMINISH FOR THE ENTIRE LAKE.
THIS HIGH WILL MORE OR LESS REMAIN IN PLACE THROUGH THE END OF THE
WEEK...RESULTING IN AN EXTENDED PERIOD OF LIGHT WINDS. THERE WILL
BE DAILY LAKE INFLUENCE FOR THE NEARSHORE WATERS AND LIKELY
VARIABILITY IN WIND DIRECTION OVER THE OPEN WATERS DUE TO THE WEAK
PRESSURE GRADIENT.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1136 AM CDT MON AUG 12 2013
.DISCUSSION...
1135 AM CDT
FOR LATE MORNING UPDATE...
LITTLE/NO CHANGE TO GOING FORECAST...EXCEPT TO TWEAK CHANCE POP
COVERAGE AT MIDDAY BASED ON CURRENT RADAR/SATELLITE TRENDS AND COLD
FRONT POSITION. SPEAKING OF THE COLD FRONT...16Z SFC ANALYSIS
INDICATED IT WAS ROUGHLY FROM A WEAK LOW PRESSURE WAVE NEAR
MILWAUKEE...WEST TO NEAR JANESVILLE WI...THEN SOUTHWEST TO NEAR
SAVANNA AND MOLINE IL.
REGIONAL RADAR MOSAIC DEPICTS SCATTERED SHRA/TSRA OVER SOUTHERN LAKE
MICHIGAN AND SOUTHWEST LOWER MICHIGAN...ASSOCIATED WITH MOISTURE
TRANSPORT AND CONVERGENCE ON THE NOSE OF WEAKENING WESTERLY LOW
LEVEL JET AND WEAK SHORT WAVE NOTED IN VAPOR IMAGERY CURRENTLY
CROSSING THE LAKE EASTBOUND. OTHERWISE ONLY A FEW SHORT-LIVED
ISOLATED SHRA HAVE BEEN NOTED DURING THE MORNING HOURS MAINLY NEAR
THE SURFACE FRONT ACROSS FAR EAST/SOUTHEAST IOWA. EXPECTATION IS
THAT THIS WILL CHANGE OVER THE NEXT FEW HOURS HOWEVER...AS WEAK COLD
FRONT SLOWLY PUSHES SOUTHEAST ACROSS NORTHERN IL AND SOUTHERN LAKE
MICHIGAN DURING INCREASINGLY FAVORABLE TIMING OF DIURNAL
INSTABILITY. LOW LEVEL WARM SECTOR SOUTH OF THE COLD FRONTAL
BOUNDARY CHARACTERIZED BY LOW 80S TEMP/MID 60S DEW POINT CONDITIONS
WITH SOME WARMING STILL TO OCCUR ESPECIALLY ACROSS THE SOUTHEASTERN
PARTS OF THE CWA WHERE MORE SUNSHINE IS OCCURRING. CURRENT SPC/RAP
MESOANALYSIS INDICATES 500-1000 J/KG MLCAPE DEVELOPING IN THOSE
AREAS...AND EXTRAPOLATION FROM 12Z DVN RAOB AND FORECAST SOUNDINGS
FROM BOTH THE 12Z WRF-NAM/MOST RECENT 15Z RAP INDICATE 1000-1500
J/KG AVAILABLE DURING THE AFTERNOON HOURS...THOUGH THIN CIRRUS COVER
MAY NEGATIVELY AFFECT THIS A BIT. AIDING THE DESTABILIZATION OF THE
LOWER LEVELS WILL BE LARGER SCALE HEIGHT FALLS ACROSS THE UPPER
MIDWEST OCCURRING IN ASSOCIATION WITH A COUPLE OF SHORT WAVES
PIVOTING SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND ANOTHER
DIGGING INTO THE UPPER MIDWEST FROM SOUTHERN MANITOBA. HOWEVER...THE
STRONGEST LARGE SCALE ASCENT AS WELL AS STRONGER MID/UPPER LEVEL
WINDS AND DEEP LAYER BULK SHEAR WILL GENERALLY REMAIN OFF TO THE
NORTH/NORTHEAST OF THE CWA THROUGH THE AFTERNOON.
THUS IT APPEARS THAT SHRA/TSRA WILL GRADUALLY DEVELOP AND INCREASE
IN COVERAGE ALONG/AHEAD OF THE WEAK COLD FRONT IS IT MOVES SOUTHEAST
ACROSS THE AREA THIS AFTERNOON (AND EARLY THIS EVENING). A FEW
STORMS MAY BECOME STRONG ACROSS THE SOUTHEAST CWA LATER THIS
AFTERNOON...PRESENTING PRIMARILY A 50-60 MPH WIND GUST THREAT. WHILE
NOT OUTLOOKED FOR SEVERE...SPC DOES HAVE OUR EAST/SOUTHEAST CWA
INCLUDED IN THE 5 PERCENT DAY 1 WIND RISK.
RATZER
&&
.PREV DISCUSSION...
316 AM CDT
THE FORECAST FOCUSES ON SHRA/TSRA TRENDS TODAY FOLLOWED BY BELOW
NORMAL TEMPS AS A STRONG HIGH PRESSURE AREA BUILDS IN BEHIND AN
APPROACHING COLD FRONT. EARLY MORNING WATER VAPOR IMAGERY SHOWS A
BROAD UPPER TROUGH OVER EASTERN CANADA...THE UPPER MIDWEST...THE
GREAT LAKES...AND NORTHERN NEW ENGLAND WITH ITS CLOSED CENTER OVER
JAMES BAY. A CORRIDOR OF RIDGING EXTENDS FROM NEW MEXICO INTO
SOUTHERN ALBERTA WITH A MUCH SMALLER CLOSED UPPER LOW OVER NORTHERN
ALBERTA. ANOTHER CLOSED UPPER LOW IS SPINNING NORTHWARD UP THE
WESTERN FLANK OF THE RIDGE FROM THE WASHING TO TO BRITISH COLUMBIA
COAST. THE LOCAL AREA IS ON THE SOUTHERN PERIPHERY OF THE BROAD
EASTERN TROUGH AND AT THE JUNCTION OF A FEED OF MOISTURE FROM THE
WEST-SOUTHWEST AND SHORTWAVE ENERGY FROM THE WEST-NORTHWEST. AT THE
SURFACE...HIGH PRESSURE STRETCHES ALONG THE OHIO VALLEY WHILE
TROUGHING STRETCHES FROM SOUTHERN QUEBEC ACROSS LAKE SUPERIOR AND
INTO CENTRAL WISCONSIN AND IOWA. SURFACE OBS SUGGEST A CLOSED LOW
OVER FAR NORTHERN WISCONSIN OR LAKE SUPERIOR WITH A COOL FRONTAL
BOUNDARY STRETCHING FROM THIS LOW SOUTHWEST TO JUST NORTH OF THE
TWIN CITIES TO EXTREME SW MINNESOTA AT 08Z.
TODAY AND TONIGHT...SHRA/TSRA POTENTIAL WILL BE A CHALLENGE TODAY.
CLUSTERS OF SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE EASTWARD
ACROSS FAR SOUTHERN WISCONSIN COINCIDENT WITH A SHARP LOW/MID LEVEL
THERMAL GRADIENT WITH ASCENT BEING AIDED BY MODEST BUT STILL FOCUSED
LOW LEVEL JET. VAD WIND PROFILES DO SHOW THE BEST CONVERGENCE
ASSOCIATED WITH THIS PRECIP WITH LESSER CONVERGENCE TO THE
SOUTHWEST ACROSS CENTRAL AND NORTHEAST IOWA WHERE CONVECTION HAS
STRUGGLED TO CONTINUE. THE BAROCLINIC ZONE IS EXPECTED TO START TO
SAG SOUTHWARD INTO FAR NORTHERN ILLINOIS OVER THE NEXT FEW HOURS
SUGGESTING THAT THERE MAY BE AT LEAST SOME SMALL INCREASE IN
SHRA/TSRA COVERAGE ACROSS THE NORTHERN CWA BUT THE LOW LEVEL JET
WILL START TO WANE SO ANY NEW ACTIVITY MAY BE SHORT LIVED. THE
AFOREMENTIONED COLD FRONT WILL BE WORKING SOUTHEASTWARD THROUGH
THE MORNING AND SHOULD REACH THE FAR NORTHWEST CWA BY LATE
MORNING. WITH THE LOW LEVEL JET WEAKENING DURING THE MORNING
PRECIP ACTIVITY LOOKS TO WANE WITH THE FRONT ITSELF NEEDING TO
TAKE OVER AS THE MAIN FORCING MECHANISM FOR NEW DEVELOPMENT.
ABUNDANT MID AND HIGH CLOUD COVER CONTINUES TO STREAM OVER THE
REGION WITH THICKER CLOUDS APPROACHING FROM THE PRECIP ACTIVITY
OVER IOWA. THIS WILL BE KEY IN DETERMINING HOW MUCH INSTABILITY
DEVELOPS AND WHERE IT DOES SO. TIMING OF THE FRONT WILL ALSO
DETERMINE HOW MUCH OF THE AREA WILL SEE A SHRA/TSRA THREAT THROUGH
THE DAY. NEAR TERM GUIDANCE SHOWS SOME DISCREPANCIES WITH THE
SPEED OF THE FRONT BUT OVERALL PREFER A SLOWER APPROACH GIVEN THE
FAIRLY UNIDIRECTIONAL STEERING FLOW AND THE PRESENCE OF THE
CURRENT CONVECTION. THIS THINKING WOULD BRING THE FRONT THROUGH
THE CHICAGO AREA AND POINTS WEST DURING MIDDAY OR EARLY AFTERNOON.
THIS LINE OF THINKING ALSO SUPPORTS THAT THE BEST THUNDER THREAT
WILL BE ACROSS THE SOUTHERN HALF OR SO OF THE AREA AS HEATING
INCREASES AND DESTABILIZATION COMMENCES. IT ALSO APPEARS THAT
THERE WILL BE SOME LARGER SCALE ASCENT PROVIDED BY A WEAK COUPLING
OF BRANCHES OF THE UPPER JET THIS AFTERNOON. WITH THIS IN MIND
WILL CONTINUE TO FOCUS THE GREATEST AFTERNOON POPS FROM NEAR GARY
SOUTHWEST TO PONTIAC AND POINTS SOUTH BUT NEW DEVELOPMENT MAY
INITIATE JUST TO THE NORTH OF THIS LINE ACROSS THE CHICAGO METRO
AND POINTS WEST ALONG INTERSTATE 80...ESPECIALLY IF THE FRONT IS A
BIT SLOWER. IN ADDITION...THERE DOES LOOK TO BE SOME INSTABILITY
BEHIND THE FRONT AND SOME SIGNS OF POSSIBLE ENHANCED CONVERGENCE
ALONG THE LAKESHORE AS WINDS TURN NORTHERLY WHICH COULD PROVIDE
SOME FOCUS FOR CONVECTION AS WELL. PROVIDED THAT THE EXPECTED
HEATING OCCURS THEN AREAS AHEAD OF THE FRONT WILL LIKELY SEE
1500-2000 J/KG OF CAPE THIS AFTERNOON. DEEP LAYER SHEAR WILL BE ON
THE ORDER OF ABOUT 30 KT. THIS WILL SUPPORT A SEVERE HAIL AND WIND
THREAT FROM THE BEST ORGANIZED STORMS ACROSS THE SOUTHERN HALF OF
THE AREA. OVERALL COVERAGE OF STORMS MAY ONLY BE SCATTERED WITH
CLOUD COVER BEING A LIMITATION SO WILL TOP POPS OUT IN THE HIGH
CHANCE CATEGORY. THE FRONT WILL BE SLOW TO EXIT TO THE SOUTH SO
SOUTHERN AREAS WILL SEE A CONTINUED SHRA/TSRA CHANCE ACROSS THE
FAR SOUTH THIS EVENING. HIGHS TODAY SHOULD RANGE FROM AROUND 80
NORTH TO THE MID 80S SOUTH.
TUESDAY THROUGH SUNDAY...STRONG HIGH PRESSURE WILL BE SPREADING
SOUTHWARD INTO THE MID AND UPPER MISSISSIPPI RIVER VALLEY TUESDAY
RESULTING IN NORTHERLY LOW LEVEL WINDS ACROSS THE CWA. THE BROAD
UPPER LEVEL TROUGH WILL HAVE SHARPENED UP WITH A TROUGH AXIS
DROPPING SOUTHEAST ACROSS THE AREA LATER IN THE DAY.
ACCORDINGLY...MUCH COOLER AIR WILL BE SPILLING INTO THE
AREA...ESPECIALLY FOLLOWING THE PASSAGE OF THE EMBEDDED TROUGH AXIS.
EXPECT H85 TEMPS TO TUMBLE FROM A PEAK OF AROUND +16C THIS AFTERNOON
TO AROUND +8C BY TUESDAY EVENING. EXPECT TUESDAY TO BE DRY DESPITE
THE PASSAGE OF THE TROUGH...GIVEN THAT THE ATMOSPHERE WILL BE
NOTICEABLY DRIER...THOUGH LOW LEVEL LAPSE RATES DO LOOK TO BE QUITE
SHARP...BUT THEY ARE SOMEWHAT SHALLOW. HIGHS WILL RANGE FROM THE
LOWER 70S WITHIN SEVERAL MILES OF LAKE MICHIGAN TO THE MID 70S
FURTHER INLAND. THE HIGH WILL CONTINUE TO PUSH SOUTH AND PARK ITSELF
OVER THE LOCAL AREA BY LATE WEDNESDAY. AN UPPER TROUGH WILL
GRADUALLY AMPLIFY AS RIDGING SHARPENS OVER THE WESTERN U.S. THROUGH
THE END OF THE WEEK. THE HIGH WILL SLOWLY WEAKEN AND THE AIRMASS
WILL SLOWLY MODIFY THROUGH THE END OF THE WEEK BUT MOST AREAS WILL
REMAIN IN THE 70S FOR HIGHS THROUGH FRIDAY...WITH MOST AREAS BEING
AROUND 80 FOR THE WEEKEND. AT THIS POINT THE REMAINDER OF THE WEEK
AND NEXT WEEKEND LOOK DRY BUT SOME MOISTURE MAY WORK ITS WAY INTO
THE EASTERN CWA TOWARD SUNDAY AS AN UPPER CIRCULATION EJECTS
NORTHWARD OVER THE MIDDLE OHIO VALLEY.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CHANCE OF SHRA/TSRA EARLY/MID AFTERNOON.
* COLD FRONT/WIND SHIFT FROM WESTERLY...TO NORTHERLY THEN TO
NORTHEASTERLY MID/LATE AFTERNOON. CMS
//DISCUSSION...UPDATED 12Z...
PRIMARY AVIATION CONCERN IS ON AN UNCERTAIN CONVECTIVE FORECAST
FOR TODAY. A COLD FRONT WILL SAG SOUTH ACROSS THE TERMINALS TODAY
FROM THE EARLY THROUGH MID TO LATE AFTERNOON. WINDS WILL TURN FROM
SOUTHWEST TO MORE WESTERLY AS THE FRONT APPROACHES AND THEN NORTH-
NORTHWEST TO NORTH BEHIND THE FRONT. ENOUGH INSTABILITY IS
EXPECTED TO BUILD TO SUPPORT SCATTERED SHRA AND TSRA MOVING
SOUTHEAST...THOUGH HAVE THE MOST CONFIDENCE IN GYY AND POINTS
SOUTH. FOR ORD/MDW/DPA...HAVE REASONABLE CONFIDENCE IN TSRA IN THE
AREA...BUT LOW CONFIDENCE IN DIRECT TERMINAL IMPACTS SO FOR NOW
HAVE GONE WITH A -SHRA VCTS MENTION FROM EARLY TO MID
AFTERNOON...WHICH WILL ALLOW FOR ASSESSMENT OF CONVECTIVE
EVOLUTION TODAY AND UPDATES/REFINEMENT IF NEEDED. IF TSRA DIRECTLY
IMPACT THE TERMINALS...WOULD EXPECT MVFR OR POSSIBLY LOWER VSBY.
NEXT CONCERN IS AN EXPECTED WIND SHIFT TO NORTHEAST AT
ORD/MDW/GYY...WHICH SHOULD OCCUR FAIRLY QUICKLY AFTER THE SHIFT TO
NORTH-NORTHWEST...BUT REFINEMENT OF THE TIMING CURRENTLY
INDICATED COULD BE NEEDED. THERE MAY BE ENOUGH LINGERING
INSTABILITY FOR SHRA DEVELOPMENT WITH THE LAKE BREEZE. WINDS WILL
DIMINISH OVERNIGHT INTO EARLY TUESDAY WITH VFR CONDITIONS EXPECTED
BUT MAY NEED TO WATCH FOR LOWER CIGS DEVELOPING AS A COOL AIR MASS
PUSHES DOWN LAKE MICHIGAN. A SECONDARY PUSH OF COOLER AIR
OCCURRING AS STRONG HIGH PRESSURE BUILDS IN FROM THE NORTHWEST ON
TUESDAY WILL RESULT IN OCCASIONALLY GUSTY NORTHEAST WINDS WITH
SPEEDS LIKELY AT 10 KT OR HIGHER.
RC
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM FOR TSRA OCCURRING NEAR THE TERMINALS EARLY/MID
AFTERNOON...LOW FOR TSRA DIRECTLY IMPACTING THE TERMINALS.
* MEDIUM FOR TIMING OF FRONTAL PASSAGE/WIND SHIFT TO NORTH-
NORTHWEST AND THEN TO NORTHEAST. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT THROUGH SUNDAY...VFR. DAILY LAKE BREEZE WIND SHIFTS
EXPECTED.
RC
&&
.MARINE...
304 AM CDT
A COLD FRONT WILL PUSH DOWN THE LAKE TODAY...WITH WINDS VEERING
FROM SOUTHWEST TO NORTH BEHIND THE FRONT. AS LARGE HIGH PRESSURE
BUILDS IN FROM THE NORTHWEST AND A COOL AIR MASS FILTERS INTO THE
REGION...WINDS WILL INCREASE TONIGHT...STRONGEST ON THE NORTH DUE
TO A SECONDARY EVEN STRONGER PUSH OF COLD AIR. SUSTAINED WINDS TO
20 KT WITH FREQUENT GUSTS INTO THE MID 20S KT RANGE ARE
EXPECTED...WITH EVEN A FEW 30 KT GUSTS POSSIBLE BEFORE WINDS BEGIN
TO EASE TOWARD DAYBREAK TUESDAY. THE SECONDARY PUSH OF COOL AIR
WILL ARRIVE ON THE SOUTH HALF OF THE LAKE DURING THE DAY ON
TUESDAY...RESULTING IN A SIMILAR INCREASE IN NORTHERLY WINDS TO 20
TO 25 KT WITH A FEW 30 KT GUSTS. WILL LIKELY NEED A SMALL CRAFT
ADVISORY FOR THE NEARSHORE WATERS STARTING SOME TIME TUESDAY
AFTERNOON AS WAVES BUILD UNTIL THEY SUBSIDE WEDNESDAY MORNING.
HIGH PRESSURE WILL ESTABLISH ITSELF OVER THE GREAT LAKES REGION
TUESDAY NIGHT...CAUSING WINDS TO DIMINISH FOR THE ENTIRE LAKE.
THIS HIGH WILL MORE OR LESS REMAIN IN PLACE THROUGH THE END OF THE
WEEK...RESULTING IN AN EXTENDED PERIOD OF LIGHT WINDS. THERE WILL
BE DAILY LAKE INFLUENCE FOR THE NEARSHORE WATERS AND LIKELY
VARIABILITY IN WIND DIRECTION OVER THE OPEN WATERS DUE TO THE WEAK
PRESSURE GRADIENT.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
109 AM CDT MON AUG 12 2013
.DISCUSSION...
837 PM CDT
SHOWERS WHICH HAVE PERSISTED NEAR THE I-88/I-90 CORRIDORS FOR MUCH
OF THE EVENING HAVE BEGUN TO SHOW A WEAKENING TREND...AND SHOULD
CONTINUE TO DISSIPATE AS THE SURFACE COOLS AND WHAT MEAGER
INSTABILITY THAT WAS THERE WEAKENS. THIS WILL ALLOW FOR A SHORT
BREAK IN PRECIPITATION TONIGHT BEFORE STRONGER SHOWERS AND
THUNDERSTORMS ARRIVE LATER. NO MAJOR CHANGES IN THINKING FOR THE
OVERNIGHT HOURS AS AN AREA OF THUNDERSTORMS CURRENTLY OVER IOWA IS
EXPECTED TO CONTINUE TO DEVELOP EASTWARD. THUNDERSTORMS SHOULD
MOVE OVER MAINLY THE NORTHERN TIER OR TWO OF COUNTIES ON THE NOSE
OF A VERY MODEST 25-30KT LOW/MID LEVEL WIND MAX THAT WILL INCREASE
MOISTURE CONVERGENCE WITHIN A NARROW CORRIDOR OF MUCAPE OF AROUND
700 J/KG. IT APPEARS THE BEST TIMING WILL BE FOR STORMS TO
INCREASE IN COVERAGE OVER THE WESTERN CWA AROUND OR JUST BEFORE
MIDNIGHT TONIGHT...THEN THE HEAVIEST PRECIP SHOULD BEGIN TO SHIFT
EAST OF THE CWA IN THE PREDAWN HOURS MONDAY.
DEUBELBEISS
//PREV DISCUSSION...
310 PM CDT
MAIN FORECAST CONCERNS FOCUS ON SHOWER/THUNDERSTORM POTENTIAL
THROUGH THE FIRST 24-36 HOURS OF THE PACKAGE...WITH THE APPROACH AND
PASSAGE OF SLOW MOVING COLD FRONT AND WEAK FRONTAL WAVE TONIGHT
THROUGH MONDAY. SURFACE HIGH PRESSURE WILL THEN SPREAD ACROSS THE
REGION MID-LATE WEEK...MAKING FOR A RELATIVELY QUIET PERIOD OF
AUGUST WEATHER...WITH TEMPERATURES AVERAGING COOLER THAN NORMAL.
THE MAIN FEATURES ON THE LOCAL WEATHER MAP THIS AFTERNOON CONSIST OF
AN AREA OF HIGH PRESSURE OVER CENTRAL ILLINOIS...WHICH CONTINUES TO
WEAKEN AND DRIFT SOUTHEAST OF THE LOCAL CWA. OF MORE INTEREST IS A
WEST-EAST SURFACE FRONTAL BOUNDARY...WHICH STRETCHES FROM THE HIGH
PLAINS OF EASTERN WYOMING...ACROSS NEBRASKA AND NORTHERN IOWA INTO
FAR NORTHWEST ILLINOIS PER 19Z ANALYSIS. WEAKENING AREAS OF
PRECIPITATION HAVE CONTINUED TO WORK EAST ACROSS SOUTHERN
MN/NORTHERN IA AND SOUTHERN WI DURING THE DAY...IN RESPONSE TO WEAK
BUT PERSISTENT WEST-SOUTHWEST LOW LEVEL FLOW INDUCED BY SHORT WAVE
PROPAGATING ACROSS THE UPPER MISSISSIPPI VALLEY...AND ASSOCIATED
WARM/MOIST ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE. WHILE
PRECIP IN THE WFO LOT CWA HAS BEEN LIMITED TO MAINLY A FEW SPRINKLES
ALONG THE IL/WI BORDER...SPC RAP MESOANALYSIS AND RAP/WRF FORECAST
SOUNDINGS CONTINUE TO DEPICT SOME WEAK INSTABILITY DEVELOPING OVER
NORTHWEST/NORTH CENTRAL IL NEAR THE SURFACE FRONT DURING THE LATE
AFTERNOON HOURS. 250-500 J/KG MUCAPE ADMITTEDLY WEAK...THOUGH
PRESENCE OF PERSISTENT WEAK CONVERGENCE/ASCENT ALONG THE BAROCLINIC
BOUNDARY DOES PRESENT SOME POTENTIAL FOR ADDITIONAL SHRA/ISOLATED
TSRA DEVELOPMENT...WITH SOME INCREASE IN CU DEVELOPMENT NOTED IN
RECENT GOES VIS IMAGERY. HAVE MAINTAINED AN ISOLATES SHRA/TSRA
MENTION AFTER 4-5 PM ACROSS PARTS OF NORTH CENTRAL ILLINOIS ROUGHLY
NORTH OF THE ROCK AND WEST OF THE FOX RIVERS.
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS THEN APPEARS TO INCREASE
FROM MID/LATE-EVENING INTO THE OVERNIGHT HOURS FROM NORTHEAST IOWA
INTO SOUTHERN WISCONSIN...AND ADJACENT PORTIONS OF NORTHERN
ILLINOIS. THIS INCREASE IS IN RESPONSE TO WEAK LARGE SCALE HEIGHT
FALLS INDICATIVE OF ASCENT WITH ADDITIONAL SHORT WAVE ENERGY
APPROACHING FROM UPSTREAM...AND INCREASING MOISTURE TRANSPORT ALONG
LOW LEVEL BAROCLINIC ZONE WITH 925-850MB WEST-SOUTHWEST 20-25 KT
FLOW AS INDICATED BY COMPLEMENTARY RAP/WRF-NAM PROGS. UPPER LEVEL
DIVERGENCE IN RIGHT ENTRANCE REGION TO UPPER LEVEL JET STREAK MAY
ALSO AID IN DEVELOPMENT FROM NORTHEAST IA INTO SOUTHWEST WI EARLIER
IN THE NIGHT...BEFORE IT TRANSLATES FARTHER EAST ACROSS MICHIGAN
LATE. WEAK SURFACE WAVE ALONG FRONT CURRENTLY OVER NORTHEAST
NEBRASKA IS PROGGED TO MOVE ACROSS SOUTHERN WI IN THE PROCESS.
WITH THE LOW LEVEL JET GRADUALLY VEERING FROM WEST-SOUTHWEST TO WEST
THROUGH THE NIGHT...THIS SHOULD HELP FOCUS FOR PRECIP SHIFT FROM
NORTHEAST IA/SOUTHWEST WI EARLY...TO SOUTHWESTERN MICHIGAN BY
SUNRISE. ALL GUIDANCE POINTS TO A FAIRLY LIMITED PORTION OF NORTHERN
IL BEING AFFECTED...PRIMARILY NORTH OF THE INTERSTATE 88 CORRIDOR.
WHILE INSTABILITY IS NOT PARTICULARLY IMPRESSIVE...UPSTREAM PWAT
VALUES ARE ROUGHLY 1.25-1.50 INCHES AND WESTERLY LOW LEVEL FLOW
MAY SUPPORT SLOW EASTWARD TRANSLATION OF RESULTING CELLS. THIS COULD
PRODUCE SOME LOCALLY HEAVY RAINFALL IF TRAINING WERE TO OCCUR.
THE TRAILING COLD FRONT IT THEN PROGGED TO PUSH SLOWLY SOUTHEAST
ACROSS THE FORECAST AREA ON MONDAY...AS THE WEAK LOW PULLS AWAY
ACROSS LOWER MICHIGAN AND DEEPER FLOW OVER THE UPPER MIDWEST BECOMES
NORTHWESTERLY WITH DIGGING UPPER TROUGH. ADDITIONAL SCATTERED SHOWER
AND THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG/AHEAD OF THE FRONT...
WITH THE GREATEST POTENTIAL ACROSS THE SOUTHEAST HALF OF THE CWA
WHERE THE FRONT WILL BE DURING THE BETTER DIURNAL INSTABILITY.
INCREASE IN MID-LEVEL FLOW ACROSS THE REGION ON MONDAY WILL LIKELY
SUPPORT A GREATER CONDITIONAL MARGINAL SEVERE WIND/HAIL THREAT
ACROSS THE SOUTHEAST COUNTIES AND AREAS EAST BY AFTERNOON.
UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHEAST CONUS INTO MONDAY
NIGHT...WITH A SECONDARY PUSH OF COOLER DRIER AIR FROM THE NORTH
HELPING TO SHOVE THE COLD FRONT OUT OF THE CWA OVERNIGHT...AND COOL
HIGH PRESSURE BUILDING SOUTHEAST ACROSS THE AREA TUESDAY-WEDNESDAY.
WITH THE MAIN UPPER TROUGH AXIS REMAINING OFF TO THE EAST OF THE
AREA...AND UPPER RIDGE TO THE WEST ACROSS ROCKIES...A PERIOD OF
FAIRLY QUIET AND COOLER THAN AVERAGE WEATHER IS ANTICIPATED. LOW
LEVEL THERMAL GUIDANCE SUGGESTS AFTERNOON HIGHS IN THE MID-UPPER 70S
DURING THE MID-WEEK PERIOD...GRADUALLY MODERATING TO THE UPPER 70S
AND LOWER 80S LATE WEEK AND NEXT WEEKEND. SOME INDICATION IN THE
LONGER RANGE GUIDANCE THAT AN UPPER LOW WILL DEVELOP ACROSS THE
LOWER OHIO OR TENNESSEE VALLEYS LATE IN THE WEEKEND...WITH BOTH THE
ECMWF AND GFS RUNS SUGGESTING THE POTENTIAL TO WRAP A LITTLE
MOISTURE INTO THE AREA FROM THE SOUTHEAST. OTHERWISE...APPEARS
MAINLY DRY THROUGH THE PERIOD BEYOND TOMORROW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SHRA AND TSRA OVERNIGHT INTO EARLY THIS MORNING.
* SHRA AND TSRA POTENTIAL EARLY THIS AFTERNOON.
* TIMING OF COLD FRONT PASSAGE AND SUBSEQUENT FLIP FROM NORTH-
NORTHWEST TO NORTHEAST WINDS.
RC
//DISCUSSION...UPDATED 06Z...
TRICKY CONVECTIVE FORECAST THROUGH MONDAY AFTERNOON. THOUGH IT
REMAINS POSSIBLE FOR SHRA AND TSRA DRIVEN BY INCREASING LOW LEVEL
WINDS OVER IA AND WI TO REMAIN NORTH OF THE TERMINALS THROUGH THE
EARLY MORNING BEFORE SHIFTING EAST...FAVOR THE IDEA OF A GRADUAL
SINKING SOUTH AND A WINDOW FOR OCCASIONAL SHOWERS AT
RFD/DPA/ORD/MDW. IF SHRA DIRECTLY IMPACT THE TERMINALS...COULD SEE
PERIODIC MVFR VSBY BUT CIGS SHOULD REMAIN VFR. CONFIDENCE IS LOW
ON TSRA DIRECTLY IMPACTING THE TERMINALS BUT THERE WILL BE ENOUGH
ELEVATED INSTABILITY TO WARRANT VCTS MENTION.
A COLD FRONT CURRENTLY STRETCHING FROM NEAR LAKE SUPERIOR TO KMSP
WILL SAG SOUTH AND REACH THE TERMINALS DURING THE
AFTERNOON...TURNING WINDS FROM WEST-SOUTHWEST TO NORTH-NORTHWEST.
AHEAD OF THE FRONT...IN THE EARLY TO MID MORNING...INSTABILITY
SHOULD WANE ENOUGH TO PRECLUDE MUCH THUNDER IN ANY ONGOING SHRA
ACTIVITY. HOWEVER ENOUGH INSTABILITY COULD BUILD IN THE LATE
MORNING INTO EARLY AFTERNOON FOR A FEW HR WINDOW FOR DPA/ORD/MDW
AND GYY TO SEE TSRA IN THE AREA BEFORE THE FRONTAL PASSAGE. IT
APPEARS THAT GYY WOULD HAVE THE BEST CHANCE TO SEE A PERIOD OF
TSRA AT THE AIRPORT...SO MAY HAVE TO ADD A TEMPO THERE ON THE NEXT
UPDATE. THERE REMAINS SOME UNCERTAINTY ON EXACT TIMING OF FRONTAL
PASSAGE...BUT ONCE IT DOES OCCUR IN THE EARLY TO MID
AFTERNOON...ORD/MDW AND GYY ARE EXPECTED TO FLIP FROM NORTH-
NORTHWEST WINDS TO NORTHEAST FAIRLY QUICKLY. WITH COOLER AIR
COMING IN BEHIND THE FRONT AND INSTABILITY EXPECTED TO ONLY SLOWLY
DIMINISH BEHIND ITS PASSAGE...MAY EVEN NEED TO WATCH FOR SHRA
DEVELOPMENT ON THE LAKE BREEZE FOR THE EASTERN TERMINALS.
RC
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW-MEDIUM CONFIDENCE IN A PERIOD OF SHRA INTO EARLY THIS
MORNING...LOW CONFIDENCE IN TSRA DIRECTLY IMPACTING THE
TERMINALS.
* LOW CONFIDENCE IN TSRA DIRECTLY IMPACTING THE TERMINALS EARLY
THIS AFTERNOON.
* LOW-MEDIUM CONFIDENCE IN TIMING OF FRONTAL PASSAGE AND WIND
SHIFT FROM NORTH-NORTHWEST TO NORTHEAST.
RC
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY THROUGH SATURDAY...VFR. NO SIG WX.
ALLSOPP
&&
.MARINE...
330 PM CDT
AS HIGH PRESSURE CENTERED OVER THE CENTRAL GREAT LAKES SHIFTS
SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT...A GENERAL SOUTHERLY
DIRECTION CAN BE EXPECTED ACROSS THE LAKE. ALTHOUGH...A WEAK
TROUGH OF LOW PRESSURE WILL MOVE EAST THROUGH ONTARIO AND THE
NORTHERN GREAT LAKES WITH WINDS THEN EXPECTED TO BEGIN SHIFTING TO
THE WEST LATE TONIGHT. AS THIS TROUGH EXITS TO THE EAST AND HIGH
PRESSURE BUILDS SOUTH OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY AND MONDAY NIGHT...WINDS WILL TURN MORE NORTHERLY ON MONDAY
WHILE INCREASING. NORTHERLY WINDS AND WAVES WILL CONTINUE TO
INCREASE/BUILD MONDAY NIGHT INTO TUESDAY...WITH WAVES HAZARDOUS TO
SMALL CRAFT POSSIBLE ACROSS BOTH THE ILLINOIS AND INDIANA
NEARSHORE WATERS TUESDAY/TUESDAY NIGHT. WINDS AND WAVES WILL BEGIN
TO DIMINISH LATER TUESDAY NIGHT INTO WEDNESDAY...AS HIGH PRESSURE
SETTLES BACK IN.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1236 PM CDT MON AUG 12 2013
.UPDATE...
ISSUED AT 1235 PM CDT MON AUG 12 2013
THE COLD FRONT CONTINUES TO MAKE STEADY PROGRESS ACROSS THE CWA
AND WAS CURRENTLY LOCATED FROM ABOUT PRINCETON IL TO JUST NORTH OF
BURLINGTON IA AND THEN INTO NW MO. A FEW SHOWERS AND ISOLATED
THUNDERSTORMS WERE LOCATED IN EXTREME SOUTHEAST IA...WESTERN IL AND
EXTREME NORTHEAST MO ALONG AND AHEAD OF THE FRONT. THE RAPID
REFRESH MESO MODEL INDICATES THE BULK OF THE SHOWERS WILL END BY
LATE THIS AFTERNOON. UPDATED GRIDS LATE THIS MORNING TO INCREASE
POPS TO 50 PERCENT IN OUR FAR SOUTHERN COUNTIES AS THE FRONT
ENCOUNTERS HIGHER MOISTURE VALUES WITH PRECIPITABLE WATER OF 1.50
INCHES.
IN THE MEANTIME...CLEARING SKIES WAS PUSHING INTO OUR FAR NW
COUNTIES AS COOLER AND DRIER AIR BEGIN FILTERING IN FROM THE
NORTHWEST.
UPDATE ISSUED AT 1120 AM CDT MON AUG 12 2013
COLD FRONT EXTENDED FROM NEAR FREEPORT TO THE QUAD CITIES TO JUST
SOUTH OF OTTUMWA AND WAS MOVING SOUTHEAST. ONLY ISOLATED SHOWERS
HAVE OCCURRED ALONG THE FRONT SO FAR WITH THE MAIN AREA OF
THUNDERSTORMS IN MISSOURI. RAPID REFRESH MESO MODEL INDICATES A
FEW SHOWERS AND THUNDERSTORMS WILL GRAZE OUR FAR SOUTHERN COUNTIES
THROUGH THE MID AFTERNOON HOURS AHEAD OF THE FRONT.
HAVE LOWERED TEMPERATURES A FEW DEGREES DUE TO EXTENSIVE CLOUD
COVER. HOWEVER...SKIES WERE CLEARING ACROSS NORTHERN AND WESTERN
IA AND NORTH INTO MN AS COOLER AND DRIER AIR FEED INTO THOSE AREAS.
UPDATE ISSUED AT 702 AM CDT MON AUG 12 2013
THE NOCTURNAL CONVECTION HAS DISSIPATED ACROSS THE AREA. TRENDS
FROM THE RAP INDICATE DOWNWARD MOTION HAS DEVELOPED SINCE MIDNIGHT
BEHIND A WEAK VORT MAX AND THIS DOWNWARD MOTION WILL PERSIST
THROUGH LATE MORNING.
THE MCS AND LIFT TOOLS GIVE MIXED SIGNALS ON THE POTENTIAL FOR
DIURNAL CONVECTION THIS AFTERNOON. IF CONVECTION DOES OCCUR...IT
WILL BE MAINLY ISOLATED TO POSSIBLY SCATTERED AND GENERALLY OVER
THE SOUTHEAST THIRD TO 40 PERCENT OF THE CWFA. TRENDS WITH THE RAP
MODEL SUGGEST ANY CONVECTION WILL BE NEARLY GONE ACROSS THE CWFA
BY EARLY EVENING. ..08..
&&
.SYNOPSIS...
ISSUED AT 319 AM CDT MON AUG 12 2013
06Z SFC ANALYSIS HAS A WEAK LOW WEST OF KMIW WITH A WARM FRONT TO
NEAR KCID. A COLD FRONT RAN FROM THE LOW INTO SOUTHERN NEBRASKA.
ANOTHER WEAK LOW WAS AT KLSE WITH A TROF CONNECTING THAT LOW WITH
THE LOW NEAR KMIW. DEW POINTS WERE IN THE 50S AND 60S ACROSS THE
MIDWEST WITH 70S ACROSS THE DEEP SOUTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CDT MON AUG 12 2013
RADAR TRENDS THE PAST SEVERAL HOURS SHOW A SLOW DECAY OF THE
PRECIPITATION ACROSS IOWA/ILLINOIS. THIS MAY BE PARTLY DUE TO THE
MCS MOVING FROM NEBRASKA INTO KANSAS INTERCEPTING THE MOIST FLOW. AT
THE SAME TIME THE OVERALL CONVERGENCE AND MOISTURE TRANSPORT ACROSS
IOWA HAS WEAKENED ALONG THE FRONT.
BASED ON TRENDS FROM THE RAP AND OTHER MODELS...THE MCS...HEAVY RAIN
AND LIFT TOOLS SUGGEST A CONTINUED SLOW DECAY OF THE CONVECTION
ACROSS THE CWFA THROUGH SUNRISE AND THE MORNING COMMUTE. BY MID TO
LATE MORNING AND CONTINUING INTO EARLY AFTERNOON VERY LITTLE IF ANY
CONVECTION WILL BE SEEN DUE TO THE NOCTURNAL CONVECTIVE MINIMA.
DIURNAL CONVECTION WILL DEVELOP DURING THE AFTERNOON AS THE
CONVECTIVE TEMPERATURE IS ACHIEVED. HOWEVER...TRENDS FROM THE RAP
SUGGEST A MAJORITY OF THIS CONVECTION WILL BE GENERALLY SOUTH OF A
KOTM TO KSQI LINE AND REMAIN ISOLATED TO SCATTERED IN NATURE.
IF ANY CONVECTION SPILLS OVER INTO THE EVENING HOURS IT WILL QUICKLY
DISSIPATE WITH THE SETTING SUN. FROM MID EVENING THROUGH SUNRISE
TUESDAY...QUIET AND DRY CONDITIONS WILL BE SEEN AS THE NEXT HIGH
PRESSURE BEGINS BUILDING INTO THE MIDWEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 319 AM CDT MON AUG 12 2013
FLOW PATTERN ALOFT TO REMAIN NORTHWESTERLY AS AREA LOCATED BETWEEN
WESTERN CONUS RIDGE AND EASTERN TROUGH. AT THE SURFACE... LARGE
EXPANSE OF CANADIAN HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH
MID-WEEK... THEN ONLY SLOWLY DRIFT INTO THE GREAT LAKES AND OHIO
VALLEY THIS WEEKEND ALL THE WHILE REMAINING THE DOMINANT WEATHER
FEATURE. THE RESULT WILL BE A PROLONGED STRETCH OF FANTASTIC
WEATHER FOR THE AREA FEATURING COOLER AND DRIER THAN NORMAL
CONDITIONS INTO NEXT WEEKEND. TUE NGT AND WED NGT LOOK TO BE THE
COOLEST OF THE STRETCH... WITH LOWS IN THE 40S LIKELY AT THE
TYPICAL COLD DRAINAGE SITES GIVEN PROGGED 850 MB TEMPS OF 7C TO 9C
AND CALM WINDS. IN ADDITION... SOME PATCHY RADIATIONAL FOG
POSSIBLE LATE TUE/WED NGTS IN THE RIVER VALLEYS AND OTHER LOW
LYING AREAS GIVEN SHALLOW STEEP LOW LEVEL INVERSION. TEMPS OVERALL
THOUGH MAINLY IN THE MID 70S TO LOWER 80S FOR HIGHS TUE-FRI AND
MAINLY IN THE 50S FOR LOWS. HAVE LOWERED MINS MOST PERIODS TUE
NGT-FRI NGT BY 1-2 DEGS BUT MAY NEED TO LOWER FURTHER AS CONTINUED
DRYING SHOULD AID IN EXPANDING DAILY DIURNAL RANGES... WITH LOWS
GENERALLY FAVORING NEAR OR BELOW THE COOL SIDE OF GUIDANCE AND
HIGHS NEAR BLEND OR TOWARD WARMER SIDE OF GUIDANCE. A SLOW WARMING
TREND ONLY TO AROUND NORMAL IS EXPECTED NEXT WEEKEND WITH 850 MB
TEMPS WARMING TO AROUND 12C TO 15C YIELDING HIGHS IN THE 80S.
BUT... EASTERLY SURFACE WINDS SHOULD ENSURE CONTINUED LOW HUMIDITY
LEVELS AND EXTREMELY COMFORTABLE CONDITIONS DESPITE THE MODERATION
IN TEMPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1235 PM CDT MON AUG 12 2013
VFR/OCNL MVFR CIGS THIS AFTERNOON AS A COLD FRONT PUSHES INTO
SOUTHEAST IA. HAVE MENTIONED VCSH AT KBRL UNTIL 21Z/12. ELSEWHERE
WILL BE DRY WITH DECREASING CLOUDS. VFR CONDS TONIGHT AND TUESDAY
MORNING AS HIGH PRESSURE BEGINS TO BUILD INTO THE AREA FROM THE
NORTH. NORTHWEST WINDS AROUND 10 KNOTS THIS AFTERNOON THEN NORTH
TO NORTHEAST TONIGHT AND TUESDAY MORNING LESS THAN 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1121 AM CDT MON AUG 12 2013
.UPDATE...
ISSUED AT 1120 AM CDT MON AUG 12 2013
COLD FRONT EXTENDED FROM NEAR FREEPORT TO THE QUAD CITIES TO JUST
SOUTH OF OTTUMWA AND WAS MOVING SOUTHEAST. ONLY ISOLATED SHOWERS
HAVE OCCURRED ALONG THE FRONT SO FAR WITH THE MAIN AREA OF
THUNDERSTORMS IN MISSOURI. RAPID REFRESH MESO MODEL INDICATES A
FEW SHOWERS AND THUNDERSTORMS WILL GRAZE OUR FAR SOUTHERN COUNTIES
THROUGH THE MID AFTERNOON HOURS AHEAD OF THE FRONT.
HAVE LOWERED TEMPERATURES A FEW DEGREES DUE TO EXTENSIVE CLOUD
COVER. HOWEVER...SKIES WERE CLEARING ACROSS NORTHERN AND WESTERN
IA AND NORTH INTO MN AS COOLER AND DRIER AIR FEED INTO THOSE AREAS.
UPDATE ISSUED AT 702 AM CDT MON AUG 12 2013
THE NOCTURNAL CONVECTION HAS DISSIPATED ACROSS THE AREA. TRENDS
FROM THE RAP INDICATE DOWNWARD MOTION HAS DEVELOPED SINCE MIDNIGHT
BEHIND A WEAK VORT MAX AND THIS DOWNWARD MOTION WILL PERSIST
THROUGH LATE MORNING.
THE MCS AND LIFT TOOLS GIVE MIXED SIGNALS ON THE POTENTIAL FOR
DIURNAL CONVECTION THIS AFTERNOON. IF CONVECTION DOES OCCUR...IT
WILL BE MAINLY ISOLATED TO POSSIBLY SCATTERED AND GENERALLY OVER
THE SOUTHEAST THIRD TO 40 PERCENT OF THE CWFA. TRENDS WITH THE RAP
MODEL SUGGEST ANY CONVECTION WILL BE NEARLY GONE ACROSS THE CWFA
BY EARLY EVENING. ..08..
&&
.SYNOPSIS...
ISSUED AT 319 AM CDT MON AUG 12 2013
06Z SFC ANALYSIS HAS A WEAK LOW WEST OF KMIW WITH A WARM FRONT TO
NEAR KCID. A COLD FRONT RAN FROM THE LOW INTO SOUTHERN NEBRASKA.
ANOTHER WEAK LOW WAS AT KLSE WITH A TROF CONNECTING THAT LOW WITH
THE LOW NEAR KMIW. DEW POINTS WERE IN THE 50S AND 60S ACROSS THE
MIDWEST WITH 70S ACROSS THE DEEP SOUTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CDT MON AUG 12 2013
RADAR TRENDS THE PAST SEVERAL HOURS SHOW A SLOW DECAY OF THE
PRECIPITATION ACROSS IOWA/ILLINOIS. THIS MAY BE PARTLY DUE TO THE
MCS MOVING FROM NEBRASKA INTO KANSAS INTERCEPTING THE MOIST FLOW. AT
THE SAME TIME THE OVERALL CONVERGENCE AND MOISTURE TRANSPORT ACROSS
IOWA HAS WEAKENED ALONG THE FRONT.
BASED ON TRENDS FROM THE RAP AND OTHER MODELS...THE MCS...HEAVY RAIN
AND LIFT TOOLS SUGGEST A CONTINUED SLOW DECAY OF THE CONVECTION
ACROSS THE CWFA THROUGH SUNRISE AND THE MORNING COMMUTE. BY MID TO
LATE MORNING AND CONTINUING INTO EARLY AFTERNOON VERY LITTLE IF ANY
CONVECTION WILL BE SEEN DUE TO THE NOCTURNAL CONVECTIVE MINIMA.
DIURNAL CONVECTION WILL DEVELOP DURING THE AFTERNOON AS THE
CONVECTIVE TEMPERATURE IS ACHIEVED. HOWEVER...TRENDS FROM THE RAP
SUGGEST A MAJORITY OF THIS CONVECTION WILL BE GENERALLY SOUTH OF A
KOTM TO KSQI LINE AND REMAIN ISOLATED TO SCATTERED IN NATURE.
IF ANY CONVECTION SPILLS OVER INTO THE EVENING HOURS IT WILL QUICKLY
DISSIPATE WITH THE SETTING SUN. FROM MID EVENING THROUGH SUNRISE
TUESDAY...QUIET AND DRY CONDITIONS WILL BE SEEN AS THE NEXT HIGH
PRESSURE BEGINS BUILDING INTO THE MIDWEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 319 AM CDT MON AUG 12 2013
FLOW PATTERN ALOFT TO REMAIN NORTHWESTERLY AS AREA LOCATED BETWEEN
WESTERN CONUS RIDGE AND EASTERN TROUGH. AT THE SURFACE... LARGE
EXPANSE OF CANADIAN HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH
MID-WEEK... THEN ONLY SLOWLY DRIFT INTO THE GREAT LAKES AND OHIO
VALLEY THIS WEEKEND ALL THE WHILE REMAINING THE DOMINANT WEATHER
FEATURE. THE RESULT WILL BE A PROLONGED STRETCH OF FANTASTIC
WEATHER FOR THE AREA FEATURING COOLER AND DRIER THAN NORMAL
CONDITIONS INTO NEXT WEEKEND. TUE NGT AND WED NGT LOOK TO BE THE
COOLEST OF THE STRETCH... WITH LOWS IN THE 40S LIKELY AT THE
TYPICAL COLD DRAINAGE SITES GIVEN PROGGED 850 MB TEMPS OF 7C TO 9C
AND CALM WINDS. IN ADDITION... SOME PATCHY RADIATIONAL FOG
POSSIBLE LATE TUE/WED NGTS IN THE RIVER VALLEYS AND OTHER LOW
LYING AREAS GIVEN SHALLOW STEEP LOW LEVEL INVERSION. TEMPS OVERALL
THOUGH MAINLY IN THE MID 70S TO LOWER 80S FOR HIGHS TUE-FRI AND
MAINLY IN THE 50S FOR LOWS. HAVE LOWERED MINS MOST PERIODS TUE
NGT-FRI NGT BY 1-2 DEGS BUT MAY NEED TO LOWER FURTHER AS CONTINUED
DRYING SHOULD AID IN EXPANDING DAILY DIURNAL RANGES... WITH LOWS
GENERALLY FAVORING NEAR OR BELOW THE COOL SIDE OF GUIDANCE AND
HIGHS NEAR BLEND OR TOWARD WARMER SIDE OF GUIDANCE. A SLOW WARMING
TREND ONLY TO AROUND NORMAL IS EXPECTED NEXT WEEKEND WITH 850 MB
TEMPS WARMING TO AROUND 12C TO 15C YIELDING HIGHS IN THE 80S.
BUT... EASTERLY SURFACE WINDS SHOULD ENSURE CONTINUED LOW HUMIDITY
LEVELS AND EXTREMELY COMFORTABLE CONDITIONS DESPITE THE MODERATION
IN TEMPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 702 AM CDT MON AUG 12 2013
VFR WX IS EXPECTED THROUGH 06Z/13. KMLI/KBRL MAY SEE VCSH OR VCTS
IN THE 18Z/12 TO 01Z/13 TIME FRAME BUT THE PROBABILITY IS 15
PERCENT OR LESS. AFT 06Z/13 VFR WX IS GENERALLY EXPECTED TO
CONTINUE BUT SOME PATCHY SHALLOW FOG MAY OCCUR DUE TO CLEAR SKIES
AND LIGHT WINDS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
718 AM CDT MON AUG 12 2013
.UPDATE...
ISSUED AT 702 AM CDT MON AUG 12 2013
THE NOCTURNAL CONVECTION HAS DISSIPATED ACROSS THE AREA. TRENDS
FROM THE RAP INDICATE DOWNWARD MOTION HAS DEVELOPED SINCE MIDNIGHT
BEHIND A WEAK VORT MAX AND THIS DOWNWARD MOTION WILL PERSIST
THROUGH LATE MORNING.
THE MCS AND LIFT TOOLS GIVE MIXED SIGNALS ON THE POTENTIAL FOR
DIURNAL CONVECTION THIS AFTERNOON. IF CONVECTION DOES OCCUR...IT
WILL BE MAINLY ISOLATED TO POSSIBLY SCATTERED AND GENERALLY OVER
THE SOUTHEAST THIRD TO 40 PERCENT OF THE CWFA. TRENDS WITH THE RAP
MODEL SUGGEST ANY CONVECTION WILL BE NEARLY GONE ACROSS THE CWFA
BY EARLY EVENING. ..08..
&&
.SYNOPSIS...
ISSUED AT 319 AM CDT MON AUG 12 2013
06Z SFC ANALYSIS HAS A WEAK LOW WEST OF KMIW WITH A WARM FRONT TO
NEAR KCID. A COLD FRONT RAN FROM THE LOW INTO SOUTHERN NEBRASKA.
ANOTHER WEAK LOW WAS AT KLSE WITH A TROF CONNECTING THAT LOW WITH
THE LOW NEAR KMIW. DEW POINTS WERE IN THE 50S AND 60S ACROSS THE
MIDWEST WITH 70S ACROSS THE DEEP SOUTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CDT MON AUG 12 2013
RADAR TRENDS THE PAST SEVERAL HOURS SHOW A SLOW DECAY OF THE
PRECIPITATION ACROSS IOWA/ILLINOIS. THIS MAY BE PARTLY DUE TO THE
MCS MOVING FROM NEBRASKA INTO KANSAS INTERCEPTING THE MOIST FLOW. AT
THE SAME TIME THE OVERALL CONVERGENCE AND MOISTURE TRANSPORT ACROSS
IOWA HAS WEAKENED ALONG THE FRONT.
BASED ON TRENDS FROM THE RAP AND OTHER MODELS...THE MCS...HEAVY RAIN
AND LIFT TOOLS SUGGEST A CONTINUED SLOW DECAY OF THE CONVECTION
ACROSS THE CWFA THROUGH SUNRISE AND THE MORNING COMMUTE. BY MID TO
LATE MORNING AND CONTINUING INTO EARLY AFTERNOON VERY LITTLE IF ANY
CONVECTION WILL BE SEEN DUE TO THE NOCTURNAL CONVECTIVE MINIMA.
DIURNAL CONVECTION WILL DEVELOP DURING THE AFTERNOON AS THE
CONVECTIVE TEMPERATURE IS ACHIEVED. HOWEVER...TRENDS FROM THE RAP
SUGGEST A MAJORITY OF THIS CONVECTION WILL BE GENERALLY SOUTH OF A
KOTM TO KSQI LINE AND REMAIN ISOLATED TO SCATTERED IN NATURE.
IF ANY CONVECTION SPILLS OVER INTO THE EVENING HOURS IT WILL QUICKLY
DISSIPATE WITH THE SETTING SUN. FROM MID EVENING THROUGH SUNRISE
TUESDAY...QUIET AND DRY CONDITIONS WILL BE SEEN AS THE NEXT HIGH
PRESSURE BEGINS BUILDING INTO THE MIDWEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 319 AM CDT MON AUG 12 2013
FLOW PATTERN ALOFT TO REMAIN NORTHWESTERLY AS AREA LOCATED BETWEEN
WESTERN CONUS RIDGE AND EASTERN TROUGH. AT THE SURFACE... LARGE
EXPANSE OF CANADIAN HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH
MID-WEEK... THEN ONLY SLOWLY DRIFT INTO THE GREAT LAKES AND OHIO
VALLEY THIS WEEKEND ALL THE WHILE REMAINING THE DOMINANT WEATHER
FEATURE. THE RESULT WILL BE A PROLONGED STRETCH OF FANTASTIC
WEATHER FOR THE AREA FEATURING COOLER AND DRIER THAN NORMAL
CONDITIONS INTO NEXT WEEKEND. TUE NGT AND WED NGT LOOK TO BE THE
COOLEST OF THE STRETCH... WITH LOWS IN THE 40S LIKELY AT THE
TYPICAL COLD DRAINAGE SITES GIVEN PROGGED 850 MB TEMPS OF 7C TO 9C
AND CALM WINDS. IN ADDITION... SOME PATCHY RADIATIONAL FOG
POSSIBLE LATE TUE/WED NGTS IN THE RIVER VALLEYS AND OTHER LOW
LYING AREAS GIVEN SHALLOW STEEP LOW LEVEL INVERSION. TEMPS OVERALL
THOUGH MAINLY IN THE MID 70S TO LOWER 80S FOR HIGHS TUE-FRI AND
MAINLY IN THE 50S FOR LOWS. HAVE LOWERED MINS MOST PERIODS TUE
NGT-FRI NGT BY 1-2 DEGS BUT MAY NEED TO LOWER FURTHER AS CONTINUED
DRYING SHOULD AID IN EXPANDING DAILY DIURNAL RANGES... WITH LOWS
GENERALLY FAVORING NEAR OR BELOW THE COOL SIDE OF GUIDANCE AND
HIGHS NEAR BLEND OR TOWARD WARMER SIDE OF GUIDANCE. A SLOW WARMING
TREND ONLY TO AROUND NORMAL IS EXPECTED NEXT WEEKEND WITH 850 MB
TEMPS WARMING TO AROUND 12C TO 15C YIELDING HIGHS IN THE 80S.
BUT... EASTERLY SURFACE WINDS SHOULD ENSURE CONTINUED LOW HUMIDITY
LEVELS AND EXTREMELY COMFORTABLE CONDITIONS DESPITE THE MODERATION
IN TEMPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 702 AM CDT MON AUG 12 2013
VFR WX IS EXPECTED THROUGH 06Z/13. KMLI/KBRL MAY SEE VCSH OR VCTS
IN THE 18Z/12 TO 01Z/13 TIME FRAME BUT THE PROBABILITY IS 15
PERCENT OR LESS. AFT 06Z/13 VFR WX IS GENERALLY EXPECTED TO
CONTINUE BUT SOME PATCHY SHALLOW FOG MAY OCCUR DUE TO CLEAR SKIES
AND LIGHT WINDS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
324 AM CDT MON AUG 12 2013
.SYNOPSIS...
ISSUED AT 319 AM CDT MON AUG 12 2013
06Z SFC ANALYSIS HAS A WEAK LOW WEST OF KMIW WITH A WARM FRONT TO
NEAR KCID. A COLD FRONT RAN FROM THE LOW INTO SOUTHERN NEBRASKA.
ANOTHER WEAK LOW WAS AT KLSE WITH A TROF CONNECTING THAT LOW WITH
THE LOW NEAR KMIW. DEW POINTS WERE IN THE 50S AND 60S ACROSS THE
MIDWEST WITH 70S ACROSS THE DEEP SOUTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CDT MON AUG 12 2013
RADAR TRENDS THE PAST SEVERAL HOURS SHOW A SLOW DECAY OF THE
PRECIPITATION ACROSS IOWA/ILLINOIS. THIS MAY BE PARTLY DUE TO THE
MCS MOVING FROM NEBRASKA INTO KANSAS INTERCEPTING THE MOIST FLOW. AT
THE SAME TIME THE OVERALL CONVERGENCE AND MOISTURE TRANSPORT ACROSS
IOWA HAS WEAKENED ALONG THE FRONT.
BASED ON TRENDS FROM THE RAP AND OTHER MODELS...THE MCS...HEAVY RAIN
AND LIFT TOOLS SUGGEST A CONTINUED SLOW DECAY OF THE CONVECTION
ACROSS THE CWFA THROUGH SUNRISE AND THE MORNING COMMUTE. BY MID TO
LATE MORNING AND CONTINUING INTO EARLY AFTERNOON VERY LITTLE IF ANY
CONVECTION WILL BE SEEN DUE TO THE NOCTURNAL CONVECTIVE MINIMA.
DIURNAL CONVECTION WILL DEVELOP DURING THE AFTERNOON AS THE
CONVECTIVE TEMPERATURE IS ACHIEVED. HOWEVER...TRENDS FROM THE RAP
SUGGEST A MAJORITY OF THIS CONVECTION WILL BE GENERALLY SOUTH OF A
KOTM TO KSQI LINE AND REMAIN ISOLATED TO SCATTERED IN NATURE.
IF ANY CONVECTION SPILLS OVER INTO THE EVENING HOURS IT WILL QUICKLY
DISSIPATE WITH THE SETTING SUN. FROM MID EVENING THROUGH SUNRISE
TUESDAY...QUIET AND DRY CONDITIONS WILL BE SEEN AS THE NEXT HIGH
PRESSURE BEGINS BUILDING INTO THE MIDWEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 319 AM CDT MON AUG 12 2013
FLOW PATTERN ALOFT TO REMAIN NORTHWESTERLY AS AREA LOCATED BETWEEN
WESTERN CONUS RIDGE AND EASTERN TROUGH. AT THE SURFACE... LARGE
EXPANSE OF CANADIAN HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH
MID-WEEK... THEN ONLY SLOWLY DRIFT INTO THE GREAT LAKES AND OHIO
VALLEY THIS WEEKEND ALL THE WHILE REMAINING THE DOMINANT WEATHER
FEATURE. THE RESULT WILL BE A PROLONGED STRETCH OF FANTASTIC
WEATHER FOR THE AREA FEATURING COOLER AND DRIER THAN NORMAL
CONDITIONS INTO NEXT WEEKEND. TUE NGT AND WED NGT LOOK TO BE THE
COOLEST OF THE STRETCH... WITH LOWS IN THE 40S LIKELY AT THE
TYPICAL COLD DRAINAGE SITES GIVEN PROGGED 850 MB TEMPS OF 7C TO 9C
AND CALM WINDS. IN ADDITION... SOME PATCHY RADIATIONAL FOG
POSSIBLE LATE TUE/WED NGTS IN THE RIVER VALLEYS AND OTHER LOW
LYING AREAS GIVEN SHALLOW STEEP LOW LEVEL INVERSION. TEMPS OVERALL
THOUGH MAINLY IN THE MID 70S TO LOWER 80S FOR HIGHS TUE-FRI AND
MAINLY IN THE 50S FOR LOWS. HAVE LOWERED MINS MOST PERIODS TUE
NGT-FRI NGT BY 1-2 DEGS BUT MAY NEED TO LOWER FURTHER AS CONTINUED
DRYING SHOULD AID IN EXPANDING DAILY DIURNAL RANGES... WITH LOWS
GENERALLY FAVORING NEAR OR BELOW THE COOL SIDE OF GUIDANCE AND
HIGHS NEAR BLEND OR TOWARD WARMER SIDE OF GUIDANCE. A SLOW WARMING
TREND ONLY TO AROUND NORMAL IS EXPECTED NEXT WEEKEND WITH 850 MB
TEMPS WARMING TO AROUND 12C TO 15C YIELDING HIGHS IN THE 80S.
BUT... EASTERLY SURFACE WINDS SHOULD ENSURE CONTINUED LOW HUMIDITY
LEVELS AND EXTREMELY COMFORTABLE CONDITIONS DESPITE THE MODERATION
IN TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 319 AM CDT MON AUG 12 2013
MAINLY VFR WX WILL BE SEEN THROUGH 06Z/13 AS A WEAK FRONT MOVES
THROUGH EASTERN IOWA AND ILLINOIS. IF CONVECTION AFFECTS A TAF
SITE...A BRIEF PERIOD OF MVFR CONDITIONS WILL BE POSSIBLE. FOR THE
MOST PART THE PROBABILITY OF A SHRA/TSRA AFFECTING A TAF SITE IS AT
BEST 20 PERCENT WITH KBRL/KMLI HAVING THE BEST CHANCE. AFT 06Z/13
MAINLY VFR WX IS EXPECTED TO CONTINUE. HOWEVER...WITH LIGHT WINDS
AND CLEARING SKIES THE POSSIBILITY DOES EXIST FOR MVFR VSBYS
DEVELOPING DUE TO FOG.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS TOPEKA KS
631 PM CDT Tue Aug 13 2013
.SHORT TERM...(This Evening through Wednesday)
Issued at 328 PM CDT TUE AUG 13 2013
Upper trough remains over the Great Lakes with a shortwave trough
extending southwestward into eastern Nebraska. This shortwave along
with a well defined MCV in southern Nebraska helped sustain a
cluster of showers and thunderstorms into the far northwest corner
of the CWA this afternoon. However...a drier and more stable
atmosphere over most of the CWA has aided a weakening trend to the
convection and expect any sustained or additional development to
occur in the western or far southern CWA until early evening. At
that time...feel majority of convection...now occurring in central
KS will have advanced further south of the vicinity with the outflow
boundary...similar to the HRRR model. Will therefore carry a dry
forecast for the overnight. Skies may become mostly clear tonight which
would support the possibility of some patchy fog. However...feel the
potential for more high clouds to advance into the area from the
northwest is high enough to negate mentioning fog for now. The dry
air and breaks in the clouds should help lows fall into the lower
60s.
On Wednesday...will maintain a dry CST as the deeper moisture and
axis of higher instability are pushed more to the west of the CWA.
Any convection through the day should remain to the west and north
of the CWA. High temperatures Wednesday will be similar
today...except slightly warmer in the north central with readings in
the lower 80s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 328 PM CDT TUE AUG 13 2013
For Wednesday night through Friday, the models have trended more
along the lines of the NAM with keeping much of the cooler and
dryer air to the northeast of the forecast area. On top of that
instead of a distinct shortwave trough moving through the
northwest flow Thursday night, models have trended towards
bringing several vort maximum through the flow late Wednesday
night through Friday. Because of this have trended min temps
warmer expecting more cloud cover and higher dewpoint temps
through the night. Will also carry a 20 to 30 percent chance pops
through the period. Forecast soundings with the higher dewpoints
show much less inhibition to convection with lower LCL heights.
because of this it is difficult to rule out precip chances with
the expected vort energy moving overhead. The airmass in general
does not change much from today. Therefore expect temps to be
relatively persistent with highs around 80 and lows in the lower
to mid 60s.
Saturday into Monday is expected to be dry with a gradual warming
trend as mid level ridging moves in from the west and insolation
increases. Uncertainty remains in the forecast for next week as
the ECMWF has shown little consistency from run to run over the
last 48 hrs. Think that there will be a small chance for precip
Monday night and Tuesday as the GFS continues to bring a shortwave
trough across the plains. However confidence is not high since the
ECMWF goes back and forth between cutting off an upper low and an
open shortwave.
&&
.AVIATION...(For the 00Z TAFs through 00Z Wednesday Evening)
Issued at 629 PM CDT TUE AUG 13 2013
VFR conditions expected through the period. Light NE winds become
ESE by the end of the forecast but should remain less than 12kts.
Will watch for possible BR at MHK/TOP sites but this time appears
enough cloud coverage to mitigate widespread development.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...63
LONG TERM...Wolters
AVIATION...67
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
600 AM CDT Mon Aug 12 2013
...Update to aviation for 12Z TAFs...
.SYNOPSIS...
ISSUED AT 343 AM CDT MON AUG 12 2013
The hemispheric scale general circulation has not changed much over
the past couple of days as a large Hudson Bay gyre continues to
influence sensible weather across much of eastern Canada and the
adjacent northeastern CONUS. A ridge of high pressure in the
mid-upper troposphere was centered across the Rockies while a
slow-moving upper low was moving north along the Pacific Northwest
coast. RAOB and RAP analysis continued to indicate a strong
subtropical jet at or just south of 30N latitude from well off the
southern California coast into Arizona and northern New Mexico.
Nocturnal water vapor loop shows a substantial mid level drying
signature tied to this jet which is disrupting the monsoonal flow
pattern across the Desert Southwest. On the mesoscale, a weak
shortwave trough moving through the Central Plains spawned the
development of a couple of mesoscale convective systems (MCS)...the
largest being across north-central Kansas. Another smaller MCS was
located across far south-central Kansas. The stronger, northern MCS
had some low level frontogenesis to aid in deeper tropospheric
upward vertical motion.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 343 AM CDT MON AUG 12 2013
The very weak frontal boundary, which promoted the development and
sustainment of the MCS across northern Kansas, will continue its
slow push into southwest Kansas through mid-morning Monday. The
front is difficult to identify on a surface chart with winds up in
Nebraska either calm or some very light variation of east...and the
MSLP gradient is very weak as well. Nevertheless, the MCS and its
outflow boundary (OFB) will provide additional convergence with the
OFB likely bisecting the southwest Kansas region by midday. None of
the convective-allowing models are showing much in the way of
thunderstorm redevelopment back across southwest Kansas this
afternoon where the remnant OFB will have likely stalled out. That
being said, the 00z and now the latest 06z run of the NAM12 do show
a more favorable QPF signal in the low level convergence zone across
southwest Kansas in the 21-00z time frame later on today. I tend to
lean more toward the NAM12 given that the lower troposphere is
fairly moist, there will be boundary layer convergence, and a
capping inversion that is not overly strong. The Storm Prediction
Center slight-risk for severe storms is focused from southwest
Kansas into northeastern Oklahoma and I cannot argue with this
forecast. Should storms form on the old front/OFB as I think they
will, then organized multi-cell or even a supercell storm could
exist given strong upper tropospheric flow (250mb winds of
65-75kts). Large hail to half-dollars and damaging wind gusts to 65
mph seem to be the best prediction for maximum severe threats in
this setup later this afternoon/evening. It is unclear how the heavy
rain threat will play out...as there will likely be another MCS
thriving during the late evening and eventually the overnight
hours...however it is extremely difficult to predict how large of an
MCS there will be and where exactly it will focus on. The most
likely location would be between the Arkansas River and the Oklahoma
border and east of Highway 83. We will not issue any flood/flash
flood headline at this time given too much uncertainty/low
confidence in the risk.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 343 AM CDT MON AUG 12 2013
Tuesday:
Large uncertainty exists Tuesday spatiotemporally with MCS activity.
The ECMWF has been persistent over the last few nights in
advertising a decent convective/QPF signal across SW Kansas. Upslope
flow from the sfc to 850 hPa, along with copious boundary layer
moisture will set the stage for decent precip event across the
region. The GFS/GEM also show MCS activity marching across the
Kansas prairies through the day. The NAM has been consistent in a
much drier solution with little in the way of precipitation. To
further uncertainty, the 4 km nested NAM is in agreement (different
cp schemes) with the operational NAM. The two cores of the WRF are
in between the global and aforementioned mesoscale models. Given the
fact that precipitable water values are forecasted to between the
75th percentile to +2SD, will keep with likely precipitation
probability percentage points. Now is not the time to be
conservative with precipitation chances, since we are dealing with a
moist and unstable atmosphere. Heavy rain will be possible as well.
Went with ECE guidance for temperatures, which shows maximums around
the 80F mark. Minimums for Wednesday morning look to be in the 60sF.
Wednesday:
With northwesterly flow aloft and low level upslope flow continuing
Wednesday, we could see diurnal thunderstorm activity. Will go with
chance precipitation probability percentage points for now with a
bias towards the ECMWF solution. Wednesdays activity should be more
isolated, and the resultant threat for heavy rain will be isolated
as well. Maximums will be pleasant and in the upper 70sF. Lows still
in the 60sF for Thursday morning.
Thursday and beyond:
Will stick with the weighted allblend solution for the rest of the
period as uncertainty continues. The bottom line is that there will
be bouts of convection thru Saturday. The forecast could be dry
Sunday, as a 500 hPa ridge extends eastward with resultant
increasing geopotential heights and a dry northerly flow aloft.
Highs should moderate to near normal by next weekend. With all the
uncertainty in the extended, we`ll tread lightly.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 600 AM CDT MON AUG 12 2013
VFR cigs expected through much of TAF pd. MVFR cigs possible this
evening in association with low clouds. Convection is possible this
afternoon and evening, but due to low confidence in model solutions,
will leave out for now.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 89 67 80 62 / 40 60 60 60
GCK 86 66 79 64 / 50 60 60 60
EHA 89 67 79 61 / 40 50 60 60
LBL 90 68 79 64 / 40 50 60 60
HYS 85 67 79 60 / 30 60 40 40
P28 90 70 82 65 / 40 60 60 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
346 AM CDT Mon Aug 12 2013
...UPDATED SYNOPSIS, SHORT TERM, LONG TERM SECTIONS..
.SYNOPSIS...
ISSUED AT 343 AM CDT MON AUG 12 2013
The hemispheric scale general circulation has not changed much over
the past couple of days as a large Hudson Bay gyre continues to
influence sensible weather across much of eastern Canada and the
adjacent northeastern CONUS. A ridge of high pressure in the
mid-upper troposphere was centered across the Rockies while a
slow-moving upper low was moving north along the Pacific Northwest
coast. RAOB and RAP analysis continued to indicate a strong
subtropical jet at or just south of 30N latitude from well off the
southern California coast into Arizona and northern New Mexico.
Nocturnal water vapor loop shows a substantial mid level drying
signature tied to this jet which is disrupting the monsoonal flow
pattern across the Desert Southwest. On the mesoscale, a weak
shortwave trough moving through the Central Plains spawned the
development of a couple of mesoscale convective systems (MCS)...the
largest being across north-central Kansas. Another smaller MCS was
located across far south-central Kansas. The stronger, northern MCS
had some low level frontogenesis to aid in deeper tropospheric
upward vertical motion.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 343 AM CDT MON AUG 12 2013
The very weak frontal boundary, which promoted the development and
sustainment of the MCS across northern Kansas, will continue its
slow push into southwest Kansas through mid-morning Monday. The
front is difficult to identify on a surface chart with winds up in
Nebraska either calm or some very light variation of east...and the
MSLP gradient is very weak as well. Nevertheless, the MCS and its
outflow boundary (OFB) will provide additional convergence with the
OFB likely bisecting the southwest Kansas region by midday. None of
the convective-allowing models are showing much in the way of
thunderstorm redevelopment back across southwest Kansas this
afternoon where the remnant OFB will have likely stalled out. That
being said, the 00z and now the latest 06z run of the NAM12 do show
a more favorable QPF signal in the low level convergence zone across
southwest Kansas in the 21-00z time frame later on today. I tend to
lean more toward the NAM12 given that the lower troposphere is
fairly moist, there will be boundary layer convergence, and a
capping inversion that is not overly strong. The Storm Prediction
Center slight-risk for severe storms is focused from southwest
Kansas into northeastern Oklahoma and I cannot argue with this
forecast. Should storms form on the old front/OFB as I think they
will, then organized multi-cell or even a supercell storm could
exist given strong upper tropospheric flow (250mb winds of
65-75kts). Large hail to half-dollars and damaging wind gusts to 65
mph seem to be the best prediction for maximum severe threats in
this setup later this afternoon/evening. It is unclear how the heavy
rain threat will play out...as there will likely be another MCS
thriving during the late evening and eventually the overnight
hours...however it is extremely difficult to predict how large of an
MCS there will be and where exactly it will focus on. The most
likely location would be between the Arkansas River and the Oklahoma
border and east of Highway 83. We will not issue any flood/flash
flood headline at this time given too much uncertainty/low
confidence in the risk.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 343 AM CDT MON AUG 12 2013
Tuesday:
Large uncertainty exists Tuesday spatiotemporally with MCS activity.
The ECMWF has been persistent over the last few nights in
advertising a decent convective/QPF signal across SW Kansas. Upslope
flow from the sfc to 850 hPa, along with copious boundary layer
moisture will set the stage for decent precip event across the
region. The GFS/GEM also show MCS activity marching across the
Kansas prairies through the day. The NAM has been consistent in a
much drier solution with little in the way of precipitation. To
further uncertainty, the 4 km nested NAM is in agreement (different
cp schemes) with the operational NAM. The two cores of the WRF are
in between the global and aforementioned mesoscale models. Given the
fact that precipitable water values are forecasted to between the
75th percentile to +2SD, will keep with likely precipitation
probability percentage points. Now is not the time to be
conservative with precipitation chances, since we are dealing with a
moist and unstable atmosphere. Heavy rain will be possible as well.
Went with ECE guidance for temperatures, which shows maximums around
the 80F mark. Minimums for Wednesday morning look to be in the 60sF.
Wednesday:
With northwesterly flow aloft and low level upslope flow continuing
Wednesday, we could see diurnal thunderstorm activity. Will go with
chance precipitation probability percentage points for now with a
bias towards the ECMWF solution. Wednesdays activity should be more
isolated, and the resultant threat for heavy rain will be isolated
as well. Maximums will be pleasant and in the upper 70sF. Lows still
in the 60sF for Thursday morning.
Thursday and beyond:
Will stick with the weighted allblend solution for the rest of the
period as uncertainty continues. The bottom line is that there will
be bouts of convection thru Saturday. The forecast could be dry
Sunday, as a 500 hPa ridge extends eastward with resultant
increasing geopotential heights and a dry northerly flow aloft.
Highs should moderate to near normal by next weekend. With all the
uncertainty in the extended, we`ll tread lightly.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1243 AM CDT MON AUG 12 2013
The overnight thunderstorm activity is expected to remain north
and east of all three TAF sites (DDC, GCK, HYS), so will be
keeping thunderstorms out of the TAF through the night. There will
be a better chance for thunderstorms on Monday afternoon, so will
be carrying a PROB30 group during the afternoon and early evening
hours as a shortwave trough moves across western Kansas and the
surface front moves down into the southwest Kansas region.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 89 67 80 62 / 40 60 60 60
GCK 86 66 79 64 / 50 60 60 60
EHA 89 67 79 61 / 40 50 60 60
LBL 90 68 79 64 / 40 50 60 60
HYS 85 67 79 60 / 30 60 40 40
P28 90 70 82 65 / 40 60 60 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS PADUCAH KY
241 PM CDT Mon Aug 12 2013
.SHORT TERM...(This Evening through Tuesday Night)
ISSUED AT 1250 PM CDT MON AUG 12 2013
It looks like the blended model approach is too slow. It lingers
pops well after fropa into/thru Tuesday. We went with the HRRR and
Nam`s more meso type solutions, which had higher resolution and
initiated well. It has higher pops but departs them more quickly
with fropa and with the aforementioned finer resolution. It models
the initial environment well, so we at least are hoping for a nice
0-6 hr init with a transition toward the Nam in the overall pop
modeling thru Tuesday. Alot will be told here with how the
remainder of the pm/into the early evening goes. Should see fairly
active/high concentration convection to continue breaking out in
moist/unstable air ahead of incoming front/energy this pm-
evening...to sweep southward with time/with perhaps additional
development along main front as well as outflow boundaries thru
the overnight hours. Meso models take the front thru tonight and
start to usher in the drier air at the lower levels late tonight-
early tmrw, which should preclude pop mention. We`ll watch closely
and also see about collab as to whether to remove pop altogetheror
leave lingering Tuesday pop. Certainly by Tue evening-overnight
all models are in agreement that the drier dew points are working
thru the column and we poise for the nice pleasant cooler/drier
air to take root from mid week on.
.LONG TERM /Wednesday through Monday/...
ISSUED AT 215 PM CDT MON AUG 12 2013
Unusually high amplitude flow pattern for the middle of August will
continue...with a large ridge in the west and a deep trough in the
Mississippi and Ohio Valley regions. The trough is forecast to
weaken late in the period /Monday/...which will result in some
semblance of a typical August pattern.
As far as the daily details...
An unseasonably strong /1023 mb/ surface high will progress slowly
east across the Great Lakes and upper Midwest Wednesday through
Thursday. This high will funnel a cool and dry air mass
southward...with 850 mb temps ranging from 10 to 12 for much of the
period. These 850 mb temps support highs only in the upper 70s with
full sun. Overnight lows will be in the lower to mid 50s. Generally
followed the cooler NAM mos for low temps...though the difference
between NAM and GFS mos is negligible in some places. It should be
noted that 850 mb temp anomalies Wed/Thu will be 2 to 3 standard
deviations below normal. The air mass will also be very dry. Model
soundings suggest nothing more than a few pancake cumulus clouds
each afternoon.
On Friday and Friday night...an inverted surface trough will
retrograde westward across the Tennessee Valley as a 500 mb
shortwave digs southeast into the Mississippi Valley. It will take a
while for the atmosphere to moisten up...so only the far southeast
counties /KHOP area/ nearest the surface trough are at risk of any
precip.
Saturday through Sunday...the upper trough will be nearly overhead.
Some guidance indicates the trough will close off into an upper low
over our region. At low levels...the inverted trough will take up
residence near or just south of our region. Dew point pooling along
the surface trough will bring dew points up through the 60s. Precip
water values are forecast to climb steadily to between 1.5 and 2
inches by Sunday /GFS model/. The models are considerably more
unstable than they were yesterday...so will add mention of thunder
for the weekend. Pops will be in the chance category in most areas
for Sunday. Most of the precip should be diurnally driven
convection.
On Monday...the upper trough is forecast to weaken and/or lift
northeast. The surface trough will dissipate...leaving only a
weakly cyclonic east to southeast flow. Precip chances will begin to
diminish from the west. Temps and humidity will gradually approach
climo.
&&
.AVIATION...
ISSUED AT 1250 PM CDT MON AUG 12 2013
MVFR cigs are prevalent as daytime heating bases in the 1500-2500
ft agl range abound. Above these decks when they temporarily
scatter is low VFR cigs in the 3500-4000 feet range with layered
higher based clouds still. Active diurnal convection will affect
KEVV/KOWB first, but all sites will develop showers/storms this
evening as front sags south. This will continue thru the overnight
hours with MVFR conditions prevailing and a small chance of IFR
cigs/vsbys in a thunderstorm. By the planning period tomorrow
morning, fropa should occur and skies should be diminishing in
clouds as a return to VFR conditions is anticipated.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
Short term/aviation...DH
Long term...MY
AREA FORECAST DISCUSSION
NWS PADUCAH KY
100 PM CDT Mon Aug 12 2013
.SHORT TERM...(This Evening through Tuesday Night)
ISSUED AT 1250 PM CDT MON AUG 12 2013
It looks like the blended model approach is too slow. It lingers
pops well after fropa into/thru Tuesday. We went with the HRRR and
Nam`s more meso type solutions, which had higher resolution and
initiated well. It has higher pops but departs them more quickly
with fropa and with the aforementioned finer resolution. It models
the initial environment well, so we at least are hoping for a nice
0-6 hr init with a transition toward the Nam in the overall pop
modeling thru Tuesday. Alot will be told here with how the
remainder of the pm/into the early evening goes. Should see fairly
active/high concentration convection to continue breaking out in
moist/unstable air ahead of incoming front/energy this pm-
evening...to sweep southward with time/with perhaps additional
development along main front as well as outflow boundaries thru
the overnight hours. Meso models take the front thru tonight and
start to usher in the drier air at the lower levels late tonight-
early tmrw, which should preclude pop mention. We`ll watch closely
and also see about collab as to whether to remove pop altogetheror
leave lingering Tuesday pop. Certainly by Tue evening-overnight
all models are in agreement that the drier dew points are working
thru the column and we poise for the nice pleasant cooler/drier
air to take root from mid week on.
.LONG TERM...(Wednesday Night through Sunday)
ISSUED AT 349 AM CDT MON AUG 12 2013
The main feature of interest beginning this period will continue to
be unseasonably strong high pressure that will stretch from the
Great Lakes region east to the Mid Atlantic coast. Unseasonably cool
and dry northeast flow will remain in place Thursday and Friday.
However, a mid/upper level trof of low pressure will slowly develop
and dig southeast into the mid MS River Valley Friday night...before
becoming nearly stationary next weekend. Guidance has been
consistent in showing an inverted surface trough forming in response
to the mid lvl troffing. Moisture associated with these features
will bring an increase in clouds...and also possibly spawn scattered
showers east of the MS River next weekend. At this point, it looks
like the atmosphere will be too stable to warrant a mention of
thunder...and the increased cloud cover will delay any appreciable
warming trend.
&&
.AVIATION...
ISSUED AT 1250 PM CDT MON AUG 12 2013
MVFR cigs are prevalent as daytime heating bases in the 1500-2500
ft agl range abound. Above these decks when they temporarily
scatter is low VFR cigs in the 3500-4000 feet range with layered
higher based clouds still. Active diurnal convection will affect
KEVV/KOWB first, but all sites will develop showers/storms this
evening as front sags south. This will continue thru the overnight
hours with MVFR conditions prevailing and a small chance of IFR
cigs/vsbys in a thunderstorm. By the planning period tomorrow
morning, fropa should occur and skies should be diminishing in
clouds as a return to VFR conditions is anticipated.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
700 AM EDT MON AUG 12 2013
.UPDATE...
ISSUED AT 650 AM EDT MON AUG 12 2013
HAVE UPDATED THE FORECAST PRIMARILY TO FINE TUNE POPS AND WX THROUGH
THE CUMBERLAND VALLEY EARLY THIS MORNING IN RESPONSE TO THE CURRENT
RADAR AND TRENDS. ALSO TWEAKED THE MORNING LOWS IN THE GRIDS ALONG
WITH THE T/TD GRIDS...AND THEIR DIURNAL CURVE...FOR THE NEXT SEVERAL
HOURS. INDICATIONS ARE THAT THE FOG REMAINS DENSE IN PLACES NORTH OF
JKL WITH SOME DENSE PATCHES IN THE SOUTH...TOO...THOUGH THE ARRIVAL
OF LOWER CLOUDS AND CONVECTION HAS HELPED TO MIX THE AIR AND LIMIT
THE FOG NEAR THE TENNESSEE BORDER. WILL KEEP THE ADVISORY GOING FOR
NOW. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EDT MON AUG 12 2013
06Z SFC ANALYSIS SHOWS THE FRONTAL BOUNDARY NOW LYING WEST TO EAST
THROUGH THE SOUTHERN TIER OF THE CWA. THIS SHOWS UP IN THE LATEST
RADAR DATA...AS WELL...WITH SIGNS OF CONVECTION ALONG IT IN EAST
KENTUCKY AND SHOWERS POPPING NEARBY THROUGH CENTRAL KENTUCKY. NORTH
OF THE BOUNDARY...CIGS HAVE CLEARED OUT AND THIS HAS ALLOWED
WIDESPREAD FOG TO FORM WITH REPORTS OF IT LOCALLY DENSE IN MANY OF
THE VALLEYS NORTH OF JKL. FOR THIS REASON...AND THE EXPECTATION OF AT
LEAST PATCHY DENSE FOG IN THE SOUTHERN VALLEYS BY DAWN...A DENSE FOG
ADVISORY IS IN EFFECT THROUGH EAST KENTUCKY UNTIL 10 AM. JUST A HINT
OF A NORTH TO SOUTH TEMPERATURE AND DEWPOINT GRADIENT EXISTS ACROSS
THE BOUNDARY. T/TD ARE CURRENTLY IN THE UPPER 60S NORTH OF THE
MOUNTAIN PARKWAY...WITH VALUES IN THE LOWER 70S TO THE SOUTH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT...AT LEAST LOCALLY...THROUGH
THE SHORT TERM AS THEY ALL DEPICT A DEEP TROUGH NORTH OF THE GREAT
LAKES AND STOUT RIDGING OVER THE DEEP SOUTH. NEAR ZONAL FLOW ALONG
THE OHIO RIVER WILL BRING SHORTWAVES ALONG WITH IT. A MORE DECENT ONE
WILL BE COMING OUT OF THE HIGH PLAINS AND START TO IMPACT EAST
KENTUCKY LATER TODAY...PASSING THROUGH TONIGHT. THIS WAVE WILL HELP
TO DRAG THE LARGER TROUGH FURTHER SOUTH INTO THE DAY TUESDAY WITH
SOME HEIGHT FALLS BY EVENING. ONCE AGAIN...THE MORE MESOSCALE
DETAILS PRIMARILY WILL GUIDE THE WEATHER THROUGH TUESDAY.
ACCORDINGLY...HAVE LEANED TOWARD THE NAM12 WITH SOME BOLSTERING OF
ITS SOLUTION FROM THE LATEST ECMWF...AND IN THE NEAR TERM...THE
CURRENT HRRR RUN.
SENSIBLE WEATHER WILL FEATURE A FOGGY START TO THE DAY FOR MOST OF
THE AREA. THE FOG WILL BURN OFF BY 10 AM AND THEN EXPECT THE NEXT
ROUND OF SHOWERS AND THUNDERSTORMS TO MOVE INTO THE CWA FROM THE
SOUTHWEST IN CONJUNCTION WITH ANOTHER RIPPLE ALONG THE STALLED
FRONT. THIS ONE WILL HAVE SOME DECENT UPPER LEVEL SUPPORT AND PLENTY
OF MOISTURE ALONG THE FRONT...SO HEAVY RAINFALL WILL REMAIN A THREAT
INTO TUESDAY MORNING...SOMETHING WE WILL HIGHLIGHT IN THE HWO. EXPECT
SOME PATCHY FOG AGAIN TONIGHT AND THEN A NORTH TO SOUTH DIMINISHING
TREND TO THE CONVECTION WITH TIME ON TUESDAY AS THE DEEPER MOISTURE
FROM FRONT STARTS TO MOVE SOUTH. TEMPS WILL BE IN THE LOWER 80S
TODAY AS THE ARRIVING CONVECTION...AND MORNING FOG...LIMIT THE RISE.
THEY LOOK EVEN COOLER TUESDAY WITH THAT FRONT AND ITS SHOWERS/TSTORMS
DROPPING SOUTH...TONIGHT WILL STILL BE RATHER WARM AND MUGGY...
THOUGH.
USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...FAVORED
THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED DIURNAL
CURVE. AS FOR POPS...HAVE ENDED UP CLOSER TO THE VERY WET MET NUMBERS
TODAY AND THEN AT OR SLIGHTLY LOWER THAN A MET/MAV CONSENSUS ON
TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 250 AM EDT MON AUG 12 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE NRN PLAINS
WILL CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER
AIR INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY
DRY FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI
MORNING AN INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP
INTO THE AREA AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. EVEN
AS THIS IS HAPPENING...AT THE 50H LEVEL A VORT MAX IS DROPPING INTO
THE CNTRL PLAINS TO REINFORCE THE ERN TROF. THIS VORT MAX WILL
DEVELOP OVER THE WEEKEND INTO A CLOSED LOW AS THE SFC HIGH PRESSURE
SLIPS TO NEW ENG AND ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION
WITH A GOOD CHANCE OF PRECIP.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR WED AND THU BEFORE THE RETURNING
SOUTHERLY FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL
CONTINUE INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK
TO AROUND 80 FOR SUN AND THE UPPER 70S FOR MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 700 AM EDT MON AUG 12 2013
FOG REMAINS A PROBLEM EARLY THIS MORNING AT THE JKL SITE WHERE VLIFR
CONDITIONS ARE HOLDING. FURTHER SOUTH...THE FOG IS MORE VARIABLE AND
LIGHTER DUE TO LOW AND MID LEVEL CLOUDS MOVING IN WITH THE NEXT BATCH
OF CONVECTION CROSSING INTO THE CUMBERLAND VALLEY. STILL EXPECT ALL
THE FOG TO CLEAR BETWEEN 13 AND 14Z. THEN WE WILL LIKELY SEE BETTER
COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS SOUTHWEST PARTS OF THE
AIR FIRST...EXPANDING TO COVER THE REST EAST KENTUCKY AROUND OR
SHORTLY AFTER 16Z. CONTINUED THE VCTS IN THE TAFS BEFORE GOING TO
STRAIGHT UP TSRA PREVAILING BY MID AFTERNOON AT LOZ AND SME. WOULD
ANTICIPATE A LULL IN THE MORE CONCENTRATED CONVECTION THIS EVENING
BEFORE ANOTHER BAND MAY RAMP UP LATE TONIGHT. HAVE TRIED TO TIME THIS
IN KEEPING WITH THE PUBLIC FORECAST FOR TONIGHT. AWAY FROM ANY
STORMS...WINDS WILL BE LIGHT AND VARIABLE THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
335 AM EDT MON AUG 12 2013
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EDT MON AUG 12 2013
06Z SFC ANALYSIS SHOWS THE FRONTAL BOUNDARY NOW LYING WEST TO EAST
THROUGH THE SOUTHERN TIER OF THE CWA. THIS SHOWS UP IN THE LATEST
RADAR DATA...AS WELL...WITH SIGNS OF CONVECTION ALONG IT IN EAST
KENTUCKY AND SHOWERS POPPING NEARBY THROUGH CENTRAL KENTUCKY. NORTH
OF THE BOUNDARY...CIGS HAVE CLEARED OUT AND THIS HAS ALLOWED
WIDESPREAD FOG TO FORM WITH REPORTS OF IT LOCALLY DENSE IN MANY OF
THE VALLEYS NORTH OF JKL. FOR THIS REASON...AND THE EXPECTATION OF AT
LEAST PATCHY DENSE FOG IN THE SOUTHERN VALLEYS BY DAWN...A DENSE FOG
ADVISORY IS IN EFFECT THROUGH EAST KENTUCKY UNTIL 10 AM. JUST A HINT
OF A NORTH TO SOUTH TEMPERATURE AND DEWPOINT GRADIENT EXISTS ACROSS
THE BOUNDARY. T/TD ARE CURRENTLY IN THE UPPER 60S NORTH OF THE
MOUNTAIN PARKWAY...WITH VALUES IN THE LOWER 70S TO THE SOUTH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT...AT LEAST LOCALLY...THROUGH
THE SHORT TERM AS THEY ALL DEPICT A DEEP TROUGH NORTH OF THE GREAT
LAKES AND STOUT RIDGING OVER THE DEEP SOUTH. NEAR ZONAL FLOW ALONG
THE OHIO RIVER WILL BRING SHORTWAVES ALONG WITH IT. A MORE DECENT ONE
WILL BE COMING OUT OF THE HIGH PLAINS AND START TO IMPACT EAST
KENTUCKY LATER TODAY...PASSING THROUGH TONIGHT. THIS WAVE WILL HELP
TO DRAG THE LARGER TROUGH FURTHER SOUTH INTO THE DAY TUESDAY WITH
SOME HEIGHT FALLS BY EVENING. ONCE AGAIN...THE MORE MESOSCALE
DETAILS PRIMARILY WILL GUIDE THE WEATHER THROUGH TUESDAY.
ACCORDINGLY...HAVE LEANED TOWARD THE NAM12 WITH SOME BOLSTERING OF
ITS SOLUTION FROM THE LATEST ECMWF...AND IN THE NEAR TERM...THE
CURRENT HRRR RUN.
SENSIBLE WEATHER WILL FEATURE A FOGGY START TO THE DAY FOR MOST OF
THE AREA. THE FOG WILL BURN OFF BY 10 AM AND THEN EXPECT THE NEXT
ROUND OF SHOWERS AND THUNDERSTORMS TO MOVE INTO THE CWA FROM THE
SOUTHWEST IN CONJUNCTION WITH ANOTHER RIPPLE ALONG THE STALLED
FRONT. THIS ONE WILL HAVE SOME DECENT UPPER LEVEL SUPPORT AND PLENTY
OF MOISTURE ALONG THE FRONT...SO HEAVY RAINFALL WILL REMAIN A THREAT
INTO TUESDAY MORNING...SOMETHING WE WILL HIGHLIGHT IN THE HWO. EXPECT
SOME PATCHY FOG AGAIN TONIGHT AND THEN A NORTH TO SOUTH DIMINISHING
TREND TO THE CONVECTION WITH TIME ON TUESDAY AS THE DEEPER MOISTURE
FROM FRONT STARTS TO MOVE SOUTH. TEMPS WILL BE IN THE LOWER 80S
TODAY AS THE ARRIVING CONVECTION...AND MORNING FOG...LIMIT THE RISE.
THEY LOOK EVEN COOLER TUESDAY WITH THAT FRONT AND ITS SHOWERS/TSTORMS
DROPPING SOUTH...TONIGHT WILL STILL BE RATHER WARM AND MUGGY...
THOUGH.
USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...FAVORED
THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED DIURNAL
CURVE. AS FOR POPS...HAVE ENDED UP CLOSER TO THE VERY WET MET NUMBERS
TODAY AND THEN AT OR SLIGHTLY LOWER THAN A MET/MAV CONSENSUS ON
TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 250 AM EDT MON AUG 12 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE NRN PLAINS
WILL CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER
AIR INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY
DRY FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI
MORNING AN INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP
INTO THE AREA AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. EVEN
AS THIS IS HAPPENING...AT THE 50H LEVEL A VORT MAX IS DROPPING INTO
THE CNTRL PLAINS TO REINFORCE THE ERN TROF. THIS VORT MAX WILL
DEVELOP OVER THE WEEKEND INTO A CLOSED LOW AS THE SFC HIGH PRESSURE
SLIPS TO NEW ENG AND ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION
WITH A GOOD CHANCE OF PRECIP.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR WED AND THU BEFORE THE RETURNING
SOUTHERLY FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL
CONTINUE INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK
TO AROUND 80 FOR SUN AND THE UPPER 70S FOR MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 225 AM EDT MON AUG 12 2013
FOG IS EXPECTED TO FORM AND THICKEN OVERNIGHT FROM NORTH TO SOUTH
ACROSS THE AREA. FOR A TIME...IT IS EXPECTED TO GET QUITE LOW AT EACH
TAF SITE. EXPECT CLEARING OF THE FOG BETWEEN 13 AND 14Z. THEN WE WILL
SEE SOME SHOWERS AND THUNDERSTORMS FORM AGAIN AROUND OR AFTER 16Z.
HAVE STARTED WITH VCTS IN THE TAFS BEFORE GOING TO STRAIGHT UP TSRA
PREVAILING BY MID AFTERNOON AT LOZ AND SME. AWAY FROM ANY STORM...
WINDS WILL BE LIGHT AND VARIABLE THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
938 PM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA OVERNIGHT INTO WEDNESDAY MORNING.
HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTH WEDNESDAY
INTO THURSDAY. THE HIGH WILL SLIDE OFF THE NEW ENGLAND COAST LATE
FRIDAY THROUGH SATURDAY...AS THE FRONTAL BOUNDARY TO THE SOUTH
LIFTS NORTH NORTHWEST ALONG THE COAST.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 930 PM...EVENING SFC ANALYSIS SHOWS A COLD FRONT ENTERING FAR
NW VA. AHEAD OF THIS FEATURE..A BKN LINE OF CONVECTION HAS FORMED
AND CURRENTLY STRETCHES FROM D.C. TO EZF TO LYH. ADDITIONAL
CONVECTION CONTINUES OVER THE VA TIDEWATER AND NE NC ALONG A PRE-
FRONTAL TROUGH. LATEST HRRR SEEMS TO HAVE A GOOD HANDLE ON ONGOING
CONVECTION AND WILL FOLLOW ITS GUIDANCE FOR THE OVN FORECAST.
BASICALLY...WE`LL SEE SCATTERED CONVECTION MOVE SE THROUGH THE
EARLY MORNING HOURS AHEAD OF THE COLD FRONT...AND PRIMARILY AFFECT
AREAS ALONG AND EAST OF THE I-95 CORRIDOR THRU 06Z. STILL SOME
DECENT INSTABILITY AROUND THIS EVENING WITH ML CAPE BETWEEN
1500-2000 J/KG AND 40 KT OF BULK SHEAR...SO CAN`T COMPLETELY RULE
OUT THREAT OF AN ISLD STRONG STORM. ADDITIONAL CONVECTION IS ALSO
EXPECTED TO CONTINUE OVER SERN ZONES. AFTER 06Z...WHAT`S LEFT OF
THE PCPN SHOULD BE LIMITED TO THE EASTERN SHORE AND PARTS OF THE
VA TIDEWATER AND NE NC. COLD FRONT CONTINUES TO DIVE SOUTH
OVERNIGHT AND SHOULD BE SOUTH OF OUR FA BY 12Z WED. NORTHERLY
WINDS BEHIND THE FRONT WILL USHER IN A DRIER AIRMASS...AS DEW
POINTS SHOULD DROP INTO THE MID 50S NW TO MID 60S SE BY 12Z WED.
MIN TEMPS WILL RANGE FROM NR 60 NW TO THE TO LWR 70S SE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
GFS/NAM IN GOOD AGREEMENT THAT THE SFC COLD FRONT WILL PUSH TO
JUST N OF CAPE HATTERAS BY 12Z/WED...THEN MOVE WELL S OF THERE WED
AFTN. SO...WILL MAINTAIN A SML CHC POP (30%) TO SLGT CHC POP (20%)
OVR NE NC AND EXTRM SE VA DURING WED MORNG. OTHERWISE...PLEASANT
WX WITH A SNY TO MSTLY SNY SKY ACRS NRN 2/3RDS ON WED...WITH PRTLY
SNY SKY ACRS SRN 1/3RD. STRONG UPR TROF SWINGING ACRS NEW ENGLAND
WILL BRING A REFRESHINGLY COOL/DRY AIRMASS TO THE MID ATLC STATES.
MAX TEMPS WILL BE IN THE UPR 70S TO ARND 80. SFC HI PRES CENTERED
OVER THE GRT LKS AND OH VLY...WILL RDG SE INTO THE MID ATLC
PROVIDING A MAINLY CLEAR SKY WED NGT. LOWS IN THE MID 50S TO LWR
60S.
LATE THU THRU FRI...GFS/NAM/ECMWF IN GENERAL AGREEMENT GRADUALLY
LIFTING MORE CLOUDS AND SOME MOISTURE BACK N INTO EXTRM SRN/SE
VA AND NE NC. FCST WILL REMAIN DRY THRU THU FOR ALL AREAS EXCEPT
NE NC...WHERE JUST A SLGT CHC FOR SHOWERS WILL BE MAINTAINED.
OTHRWISE...PRTLY TO MSTLY SNY AND COMFORTABLE CONDITIONS WITH
HIGHS IN THE UPR 70S TO LWR 80S. GRADUAL INCREASE IN DWPTS AND
CLOUDS FM SE TO NW THU NGT AND FRI...AS THE FRNTL BOUNDARY TO THE
S STARTS TO LIFT BACK NNW. WILL HAVE SLGT CHC POPS OVR NE NC THU
NGT...AND CHC POPS OVR EXTRM SE VA AND NE NC FRI AFTN/EVENG. LOWS
THU NGT IN THE UPR 50S TO MID 60S. HIGHS ON FRI IN THE UPR 70S TO
ARND 80.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE MODELS CONTINUE TO HANDLE THE AMPLIFIED UPPER LEVEL
PATTERN OVER THE CONUS WELL THROUGH THE EXTENDED. ANOMALOUS UPPER
LOW WILL LOCATE OVER THE MID MS VALLEY SAT AS STRONG HIGH PRESSURE
RESIDES OVER THE WRN ATLANTIC. THE INCREASED S-SWLY FLOW BTWN HIGH
AND LOW PRESSURE WILL ADVECT DEEP ABUNDANT MOISTURE (PRECIP WATERS
2.00 TO 2.25 INCHES) INTO THE REGION FROM THE ERN GULF AND WRN
ATLANTIC SAT-SUN. STRONG BERMUDA HIGH PRESSURE WILL BEGIN TO BUILD
WWD SUN ALONG THE SE STATES. MEANWHILE...A NEARLY STATIONARY WAVY
FRONT WILL REMAIN ALONG THE SE AND LOWER MID ATLANTIC COAST. THE
FRONT WILL BE THE FOCUS FOR SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS THROUGH EARLY NEXT WEEK. AS MOISTURE CONTINUES TO LIFT
INTO THE REGION...THE CLOSE PROXIMITY OF THE UPPER TROUGH WILL ALLOW
SHOWERS TO EXTEND OVER THE REMAINING MID ATLANTIC SAT-SUN. HAVE
OPTED TO INCREASE POPS OVER THE SE TO HIGH END SAT-SUN AS SHORTWAVE
ENERGY LIFTS ALONG THE FRONT PRODUCING SEVERAL ROUNDS OF SHOWERS.
INSTABILITY WILL BE LIMITED...SO WILL ONLY MENTION SLIGHT CHANCE TS
ALONG THE FRONT OVER SE VA/NE NC. FRONT MAY RETROGRADE SLIGHTLY SUN
AS HIGH PRESSURE BUILDS FROM THE WEST. ALSO...SFC HIGH PRESSURE WILL
TRANSITION OFF THE NE COAST SUN...ALLOWING HIGH PRESSURE TO WEDGE
INTO THE LOCAL AREA. RESULTANT ONSHORE FLOW WILL RESULT IN A CLOUDY
AND WET DAY SUNDAY. TEMPS MAY STRUGGLE TO GET OUT OF THE 70S IF THE
MODELS VERIFY. HIGHEST QPF EXPECTED TO BE ALONG AND TO THE WEST OF
THE FRONT. WPC DAY 4-7 QPF PLACES A MAXIMUM OF 1 TO 3 INCHES ALONG
THE SE COAST INTO SE VA. THUS...PERIODS OF HEAVY RAIN WILL BE
POSSIBLE ALONG THE FRONT.
OTHERWISE...UPPER TROUGH WILL BEGIN TO DEAMPLIFY MON AS ADDITIONAL
SHORTWAVE ENERGY MOVES INTO THE INTERMOUNTAIN WEST. MOISTURE WILL
BEGIN TO SCOUR OUT AS A RESULT...WITH POPS MAINLY TIED TO THE FRONT
OVER SE VA/NE NC. LITTLE CHANGE INTO TUES AS THE UPPER LOW CONTINUES
TO SLOWLY LIFT NEWD. WITH THE FRONT CLOSE BY AND PLENTY OF REMNANT
MOISTURE...WILL KEEP SLIGHT CHANCE-CHANCE POPS TUES.
TO NOTE...SOME MEDIUM RANGE GUIDANCE IS MORE ENTHUSIASTIC ABOUT A
TROPICAL WAVE MOVING INTO THE GULF COAST/SE US BY SUN.
HOWEVER...NHC/WPC CONSENSUS IS THAT THE WAVE WILL REMAIN OVER THE
SRN GULF.
PERIODS OF CLOUDS...SHOWERS AND ONSHORE FLOW WILL PREVENT TEMPS FROM
REACHING THEIR FULL POTENTIAL...SO HAVE OPTED TO UNDERCUT MOS
GUIDANCE DURING THE EXTENDED. HIGHS WILL GENERALLY BE IN THE UPPER
70S TO LOW 80S (-1 TO -1.5 STD DEV).
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT CONTS TO ADVANCE TOWARDS THE AREA. SCATTERED SHOWERS
AND TSTMS WILL LIKELY AFFECT THE REGION THRU MIDNIGHT AS THE FRONT
MOVES SLOWLY SE. VFR CONDS WILL GENERALLY PREVAIL OVER THE TAF
SITES BUT ANY STORM ACTIVITY COULD REDUCE CONDS TO MVFR/IFR FOR A
SHORT PERIOD OF TIME. WINDS WILL BE MOSTLY SW-WNW AHEAD OF THE FRONT
AND THEN SHFT NW-NE AFTER FROPA. A SECONDARY SURGE OF DRIER AIR WILL
FOLLOW THE FRONTAL BNDRY AND WILL HELP TO INCREASE WINDS DURING
THE OVERNIGHT HOURS. EXPECT GUSTY WINDS 15-25 KT EARLY WED INTO
THE AFTN. VFR CONDS ARE EXPECTED WED AS SLIGHTLY AS HIGH PRES
BUILD IN FROM THE NORTH.
&&
.MARINE...
MODELS ARE IN GOOD AGREEMENT WITH THE TIMING OF THE NEXT COLD FRONT
WHICH WILL MAKE IT INTO THE AREA LATE TNGT AND PUSHES SOUTH INTO
NC EARLY WED. WHILE THE INITIAL GRADIENT IS NOT OVERLY
IMPRESSIVE...SCA CONDITIONS WILL OCCUR WITH NORTHERLY WINDS OF 20
KT GUSTING TO ~25 KT OVER THE BAY...RIVERS AND CURRITUCK SOUND AS
COLDER AIR ALOFT MOVES OVER THE WARM WATERS LATE TNGT AND EARLY WED.
MOST MODELS ARE SHOWING THIS SURGE...SO CONFIDENCE IS FAIRLY HIGH
IN THE SCA CONDITIONS OCCURRING OVER THESE WATERS. A QUESTION STILL
REMAINS AS TO IF THE COASTAL WATERS REACH SCA LEVELS DURING THIS
EVENT. FORECAST MODELS HAVE TRENDED UP IN REGARDS TO WINDS SPEEDS
BUT CURRENT FORECAST KEEPS WINDS JUST BELOW SCA LEVELS FOR THE
COASTAL WATERS. BY WED AFTN...WINDS SHOULD SUBSIDE TO 10-15 KT OR
LESS WITH HIGH PRESSURE MOVING OVER THE AREA. THE COMBINATION OF SFC
HIGH PRESSURE CENTERED OVER NORTHERN PORTIONS OF THE WATERS AND A
TROUGH OF LOW PRESSURE ALONG THE SE COAST WILL LEAD TO PERSISTENT NE
FLOW INTO THU. THIS WILL KEEP SEAS ALONG THE COAST AROUND 3 FT OR
GREATER WITH WAVES 2 FT OVER THE BAY WITH 5 FT SEAS POSSIBLE IN THE
SOUTHERN COASTAL ZONES BETWEEN CAPE CHARLES LIGHT AND CURRITUCK
BEACH LIGHT.
FOR THE EXTENDED...UNSETTLED WEATHER WILL RETURN TO THE WATERS LATE
FRI-MON AS A COASTAL FRONT ORIENTS ALONG THE SE AND MID ATLANTIC
COASTS. WINDS WILL REMAIN SUB SCA AOB 15 KT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EDT WEDNESDAY FOR
ANZ632-634-636>638.
SMALL CRAFT ADVISORY FROM 1 AM TO 1 PM EDT WEDNESDAY FOR
ANZ630-631-635.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT WEDNESDAY FOR
ANZ633.
&&
$$
SYNOPSIS...TMG
NEAR TERM...JDM/TMG
SHORT TERM...LKB/TMG
LONG TERM...SAM
AVIATION...JEF/DAP
MARINE...SAM/DAP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
504 AM EDT MON AUG 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT MON AUG 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER
JAMES BAY WITH A WELL-DEFINED SHORTWAVE TROUGH/PV ANOMALY
TO THE WEST NEAR CYPL. A WEAK 850-700 MB TROUGH SUPPORTED SOME ISOLD
SHOWERS THROUGH N CNTRL UPPER MI AND ERN LAKE SUPERIOR. AT THE
SFC...A TROUGH EXTENDED THROUGH WRN LAKE SUPERIOR AHEAD OF A COLD
FRONT DROPPING THROUGH NRN ONTARIO TO NEAR CYGQ.
TODAY...EXPECT THAT THE NW ONTARIO SHRTWV BRUSHING UPPER MI DURING
INCREASED DAYTIME HEATING AND LAKE BREEZE BOUNDARY DEVELOPMENT...
WILL BE ENOUGH TO TRIGGER ADDITIONAL ISOLD/SCT SHOWERS OVER MAINLY
THE CNTRL AND ERN CWA. WITH MLCAPE VALUES ONLY FCST INTO THE 100-300
J/KG RANGE...AND THE STRONGER 700-300 MB QVECTOR CONV WITH THE SHRTWV
AND STEEPER MID LEVEL LAPSE RATES REMAINING TO THE NORTH...TSRA WERE
NOT MENTIONED. CLOUDS AND INCREASING NRLY FLOW WILL KEEP TEMPS BELOW
NORMAL WITH HIGHS IN THE UPPER 60S NORTH AND LOWER 70S SOUTH.
TONIGHT...ANY REMAINING SHOWERS ARE EXPECTED TO DIMINISH QUICKLY AS
SUBSIDENCE INCREASES IN THE WAKE OF THE SHRTWV AND DAYTIME HEATING
SUBSIDES. WITH CLEARING SKIES AND PWAT VALUES FALLING TO AROUND 0.50
INCH(50 PCT OR NORMAL)...TEMPS OVER THE INTERIOR WEST ARE EXPECTED
TO FALL INTO THE LOWER 40S...CLOSER TO THE LOWER END OF GUIDANCE.
LINGERING LOW LEVEL NW FLOW OVER THE EAST SHOULD STILL BE STRONG
ENOUGH TO KEEP TEMPS FROM DROPPING OFF AS MUCH WITH MINS ONLY IN THE
UPPER 40S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM EDT MON AUG 12 2013
COOL AND DRY WEATHER IS EXPECTED THROUGH THE WORK WEEK AS HIGH
PRESSURE DOMINATES THE PATTERN. A SERIES OF WEAK SHORTWAVES ROTATING
AROUND THE BACKSIDE OF AN EASTERN CANADIAN TROUGH COULD BRING SOME
INCREASED CLOUDINESS AT TIMES...BUT LITTLE IF ANY PRECIP IS
EXPECTED.
TUESDAY AND TUESDAY NIGHT...DEEP TROUGHING CENTERED OVER WESTERN
QUEBEC IS CURRENTLY COMPRISED OF A HALF DOZEN OR SO EMBEDDED
SHORTWAVES THAT ARE DEPICTED IN WV IMAGERY. ONE WAVE OVER NORTHERN
HUDSON BAY IS PROGGED TO BE MOVING SE ACROSS THE CWA AT THE START OF
THE PERIOD. THIS FEATURE HAS COMPLICATED FORECASTS FOR TUESDAY AS IT
WAS NOT PICKED UP WELL BY ANY MODEL UNTIL WITHIN THE PAST 36 HRS.
THE WAVE WILL OUTRUN PEAK HEATING...SO WITH DEPLETED MOISTURE BEHIND
TODAYS SYSTEM...CAPPING AROUND H7 BEHIND THE WAVE...AND SFC DEW
POINTS IN THE 40S...WOULD EXPECT TO SEE ONLY A DIURNAL CUMULUS FIELD
WITH POSSIBLY SOME SPRINKLES. WILL OPT TO KEEP PRECIP MENTION OUT OF
THE FORECAST ATTM...BUT WILL BOOST UP AFTERNOON CLOUD COVER A BIT.
QUITE A COOL NIGHT IS IN THE MAKING TUESDAY NIGHT AS THE AXIS OF
HIGH PRESSURE BUILDING INTO THE REGION SETTLES OVER THE WESTERN CWA.
PWAT AROUND 0.5 INCHES AND LIGHT WINDS WILL PROMOTE EXCELLENT
RADIATIONAL COOLING ACROSS THE AREA. CONTINUED TO EMPLOY
GUIDANCE...CHIEFLY BIAS CORRECTED MOS...THAT HAS PERFORMED
EXCEPTIONALLY WELL WITH SIMILAR NIGHTS OVER THE PAST SEVERAL WEEKS.
CURRENT FORECAST IS FOR UPPER 30S INTERIOR WEST TO LOW 40S ELSEWHERE
INLAND TO AROUND 50 VERY NEAR THE GREAT LAKES SHORES. ANOTHER WEAK
SHORTWAVE WILL TRACK SE ACROSS THE AREA LATE IN THE NIGHT...BUT WITH
LITTLE MOISTURE...DO NOT EVEN EXPECT MID CLOUDS.
WEDNESDAY THROUGH THURSDAY...ANOTHER WEAK WAVE WILL PUSH SE ACROSS
THE CWA WEDNESDAY MORNING...AND YET ANOTHER ONE THURSDAY MORNING.
BOTH LOOK RATHER BENIGN ATTM WITH MOISTURE STILL QUITE LOW. BOTH
DAYS SHOULD SEE SHALLOW CUMULUS DEVELOPMENT INLAND WITH SUBSTANTIAL
CAPPING AT H7. DEPARTING SFC HIGH PRESSURE WILL BRING A COUPLE MORE
COOL NIGHTS BEFORE FRIDAY. HAVE CONTINUED TO USE COLDER GUIDANCE FOR
THESE NIGHTS AS PWAT WILL STILL BE BELOW 0.7 INCHES.
FRIDAY THROUGH SUNDAY...A WARMING TREND IS IN STORE BY THE END OF
THE WEEK...WITH WIDESPREAD 70S AND A FEW 80S TIPPING THE SCALE BACK
TO ABOVE AVERAGE TEMPS. MODEL GUIDANCE IS IN DECENT AGREEMENT THAT A
TROUGH FROM WESTERN CANADA WILL BEGIN ERODING RIDGING OVER THE
NORTHERN PLAINS BY LATE THURSDAY. HOWEVER...THERE IS SOME
DISAGREEMENT AS TO THE MAGNITUDE AND DURATION OF THIS PROCESS. THE
ECMWF IS MUCH MORE CONSERVATIVE THAN THE GFS IN BRINGING THE TROUGH
INTO THE UPPER MS VALLEY...HOLDING OFF UNTIL LATE NEXT WEEKEND. THE
GFS BRINGS PRECIP INTO THE WESTERN CWA AS EARLY AS FRIDAY NIGHT.
BOTH HAVE BEEN QUITE CONSISTENT WITH THEIR RESPECTIVE FORECASTS...SO
CANNOT RULE OUT EITHER. EXPERIENCE TENDS TO LEAN TOWARD THE SLOWER
PROGRESSION OF THE ECMWF IN BREAKING DOWN A SUMMERTIME RIDGE.
HOWEVER...GIVEN UNCERTAINTY...WILL MAINTAIN CONSENSUS FORECAST OF
SLIGHT CHANCE OF SHOWERS AND STORMS BEGINNING LATE SATURDAY INTO
SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 151 AM EDT MON AUG 12 2013
THE APRCH OF ANOTHER DISTURBANCE LATER THIS MRNG INTO THE AFTN
ACROSS LK SUP WL BRING A THREAT OF MORE -SHRA TO MAINLY CMX AND
SAW...BUT CONFIDENCE ATTM REMAINS TOO LO TO INCLUDE MORE THAN VCSH
IN THE TAFS. ANY SHRA WL END LATER THIS AFTN WITH DRYING/SUBSIDENCE
IN THE WAKE OF THE DEPARTING DISTURBANCE. SINCE THE LLVLS WL REMAIN
DRY THRU THE FCST PERIOD...EXPECT VFR CONDITIONS AT ALL 3 TAF SITES
EVEN IF THERE IS A -SHRA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT MON AUG 12 2013
AFTER A TROUGH MOVES THROUGH LAKE SUPERIOR EARLY...A WEAK COLD FRONT
WILL MOVE THROUGH LAKE SUPERIOR TODAY. HOWEVER...WINDS ARE EXPECTED
TO REMAIN LESS THAN 20 KNOTS. HIGH PRESSURE WILL RESUME CONTROL OF
THE WRN GREAT LAKES TUESDAY THROUGH THE END OF THE WEEK TO KEEP
WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
105 PM CDT Mon Aug 12 2013
.UPDATE:
Issued at 847 AM CDT Mon Aug 12 2013
Made some smap adjustments to pops and temperatures for today. The
cluster of storms moving into central missouri seems to be living
longer than previously thought, so have increased pops to likely
generally along the i-70 corridor in central and parts of eastern
misouri and lowered highs today in that same region. Not sure how
much longer the cluster will last, but 850mb RUC continues to show
good moisture convergence into the afternoon as a weak low level
jet continues to veer. Will continue to monitor and update as the
stoms evolve.
Carney
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 337 AM CDT Mon Aug 12 2013
07Z surface analysis revealed three boundaries of interest across
the region. First, a warm front was lifting northward through
central and southeastern MO. WAA with this boundary was contributing
to isolated showers/thunderstorms early this morning across
southeastern MO and extreme southern IL. Second, active convection
had generated an outflow boundary across portions of KS/NE/IA.
Third, a synoptic cold front was moving southward through SD/MN.
None of these features is especially strong, and model forecasts
suggest that the warmer air behind the warm front will simply
reinforce the broader baroclinic zone. Another way to look at it is
that the aforementioned boundaries will fall into the same broad
pressure trough which stretches from KS to WI. Regardless, H7-H5
lapse rates of around 6 deg C/km along with up to 1000 J/kg of CAPE
ahead of an advancing cold front should be sufficient for scattered
thunderstorms, especially during the afternoon and early evening
hours.
Kanofsky
.LONG TERM: (Tonight through Sunday)
Issued at 337 AM CDT Mon Aug 12 2013
Thunderstorm threat should persist across most of the CWA tonight,
but am beginning to think that primary threat may be during the
evening and be associated with "leftover" convection from the
afternoon hours. Airmass is progged to stabilize quite a bit during
the evening and convergence along ill-defined front becomes almost
non-existent after 06z, so almost all UVV will come from weak
shortwave energy dropping across the area. Have gone ahead and
dropped the POPs in our far N counties after 06z with passage of the
cold front.
Concern also remains for precipitation chances on Tuesday. There is
better agreement in the 00z runs pointing to active convection
working across SW MO during the morning. While the POP/QPF bullseye
with this activity should be well southwest of our CWA, primary
question is if and/or how much of this activity will be able to work
into our CWA as it shears off to the southeast with the slowly
increasing NW mid level flow. For now I have held onto slight
chance POPs as far north as a COU-SAR line for the morning hours;
this still may be too far north but will wait for today`s model runs
to confirm this above thinking before making additional cuts to
POPs.
For the remainder of the week, medium range solutions are still
indicating that a series of shortwaves rotating around upper low
over southeast Canada will lower heights over the eastern CONUS.
This shift in the UA pattern will allow Canadian high pressure to
build into, and then become locked over, the mid-Mississippi Valley.
The net result should be several days of dry and relatively cool
August weather. There has been little run-to-run change in the
progged temperature profile across the region during this time, so
it still looks like temperatures in the Wednesday-Friday time frame
will be averaging 5-10 degrees below normal. Progged 850mb temps as
well as MOS guidance suggests highs in the 75-80 degree range, with
lows primarily in the 50s.
00z GFS and ECMWF are still hinting at a secondary shortwave
dropping into the mid-Mississippi valley and developing a cut-off
low in the vicinity of the lower Ohio valley heading into the
weekend. This certainly bears watching, but latest guidance
suggests that primary moisture surge, and precipitation threat, will
be ahead of this feature, and primarily east of our CWA. So for
now have maintained a dry forecast for the weekend, with gradual
modification of the airmass allowing for a slow warming trend.
Truett
&&
.AVIATION: (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1252 PM CDT Mon Aug 12 2013
Primary concern continues to be thunderstorms moving across the
area. While the majority of the area remains vfr, a swath of low
mvfr and ifr conditions associated with the storms will move east-
southeast at around 25 mph. expect that the storms will clear our
eastern/southeastern zones by 00z this evening. northerly flow
will freshen this evening and overnight which will bring in some
drier air. however, the sky is expected to clear out and am unsure
what the fog potential will be as the drier air filters in. think
the greatest potential for fog will be along and south of the I-70
corridor where it rained and the driest air will not penetrate
tonight.
Specifics for KSTL:
Expect showers and thunderstorms to continue at Lambert through
19Z or so. Intermittant IFR vsbys in moderate rain are possible
until the rain clears the terminal. intermittant showers are
possible the remainder of the afternoon. expect the sky to clear
overnight, but there is the potential for fog late. a northerly
wind will bring drier air into the region, but am not sure how
much drying there will be with persistent cloud cover until late
this afternoon and the northerly flow staying fairly light. while
there`s no mention in the taf right now, mvfr or even ifr fog may
be possible. will pass these thoughts along to the next shift to
reevaluate.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
852 AM CDT Mon Aug 12 2013
.UPDATE:
Issued at 847 AM CDT Mon Aug 12 2013
Made some smap adjustments to pops and temperatures for today. The
cluster of storms moving into central missouri seems to be living
longer than previously thought, so have increased pops to likely
generally along the i-70 corridor in central and parts of eastern
misouri and lowered highs today in that same region. Not sure how
much longer the cluster will last, but 850mb RUC continues to show
good moisture convergence into the afternoon as a weak low level
jet continues to veer. Will continue to monitor and update as the
stoms evolve.
Carney
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 337 AM CDT Mon Aug 12 2013
07Z surface analysis revealed three boundaries of interest across
the region. First, a warm front was lifting northward through
central and southeastern MO. WAA with this boundary was contributing
to isolated showers/thunderstorms early this morning across
southeastern MO and extreme southern IL. Second, active convection
had generated an outflow boundary across portions of KS/NE/IA.
Third, a synoptic cold front was moving southward through SD/MN.
None of these features is especially strong, and model forecasts
suggest that the warmer air behind the warm front will simply
reinforce the broader baroclinic zone. Another way to look at it is
that the aforementioned boundaries will fall into the same broad
pressure trough which stretches from KS to WI. Regardless, H7-H5
lapse rates of around 6 deg C/km along with up to 1000 J/kg of CAPE
ahead of an advancing cold front should be sufficient for scattered
thunderstorms, especially during the afternoon and early evening
hours.
Kanofsky
.LONG TERM: (Tonight through Sunday)
Issued at 337 AM CDT Mon Aug 12 2013
Thunderstorm threat should persist across most of the CWA tonight,
but am beginning to think that primary threat may be during the
evening and be associated with "leftover" convection from the
afternoon hours. Airmass is progged to stabilize quite a bit during
the evening and convergence along ill-defined front becomes almost
non-existent after 06z, so almost all UVV will come from weak
shortwave energy dropping across the area. Have gone ahead and
dropped the POPs in our far N counties after 06z with passage of the
cold front.
Concern also remains for precipitation chances on Tuesday. There is
better agreement in the 00z runs pointing to active convection
working across SW MO during the morning. While the POP/QPF bullseye
with this activity should be well southwest of our CWA, primary
question is if and/or how much of this activity will be able to work
into our CWA as it shears off to the southeast with the slowly
increasing NW mid level flow. For now I have held onto slight
chance POPs as far north as a COU-SAR line for the morning hours;
this still may be too far north but will wait for today`s model runs
to confirm this above thinking before making additional cuts to
POPs.
For the remainder of the week, medium range solutions are still
indicating that a series of shortwaves rotating around upper low
over southeast Canada will lower heights over the eastern CONUS.
This shift in the UA pattern will allow Canadian high pressure to
build into, and then become locked over, the mid-Mississippi Valley.
The net result should be several days of dry and relatively cool
August weather. There has been little run-to-run change in the
progged temperature profile across the region during this time, so
it still looks like temperatures in the Wednesday-Friday time frame
will be averaging 5-10 degrees below normal. Progged 850mb temps as
well as MOS guidance suggests highs in the 75-80 degree range, with
lows primarily in the 50s.
00z GFS and ECMWF are still hinting at a secondary shortwave
dropping into the mid-Mississippi valley and developing a cut-off
low in the vicinity of the lower Ohio valley heading into the
weekend. This certainly bears watching, but latest guidance
suggests that primary moisture surge, and precipitation threat, will
be ahead of this feature, and primarily east of our CWA. So for
now have maintained a dry forecast for the weekend, with gradual
modification of the airmass allowing for a slow warming trend.
Truett
&&
.AVIATION: (For the 12z TAFs through 12z Tuesday Morning)
Issued at 549 AM CDT Mon Aug 12 2013
Showers and thunderstorms are expected to develop across MO/IL
today ahead of an approaching cold front. Winds will turn westerly
to northwesterly behind the front, then continue veering
overnight. Periods of MVFR/IFR conditions will be possible when
showers/thunderstorms move directly over the terminals.
Specifics for KSTL: KSTL was on the northern edge of a warm front
early this morning. Once the warm front lifts northward, winds
will switch from southeasterly to southerly. Showers and
thunderstorms are expected to develop near KSTL this afternoon
ahead of an approaching cold front. Winds will turn northwesterly
behind the front, then continue veering overnight and become
northeasterly tomorrow morning. Periods of MVFR/IFR conditions
will be possible when showers/thunderstorms move directly over the
terminal.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
649 AM CDT Mon Aug 12 2013
...Flash Flood Watch Now In Effect for the Entire Forecast Area...
.MESOSCALE DISCUSSION...
Issued AT 645 AM CDT MON AUG 12 2013
A large area of convection continues to spread across eastern
Kansas toward western Missouri this morning. A veered low level
jet will support this activity spreading east into southern
Missouri this morning. Precipitable water values near 1.75 inches
and 850 mb dewpoints near 15 degrees Celsius will support
efficient rainfall production. RAP model analysis suggest a layer
of dry air in the mid levels but expect this to be overcome by
advection of deeper moisture into the area. With the approach of
this expansive area of rain the Flash Flood Watch has been
expanded to cover the entire forecast area beginning this morning.
Some areas of central and eastern Missouri may be dropped later
today if precipitation and model trends dictate.
Most unstable CAPE of 1000 to 2000 J/KG will support thunderstorms
and a few stronger updrafts. Severe weather is not expected this
morning but winds to 40 mph will be possible in the stronger
convection.
&&
.SHORT TERM...(Today through Wednesday) ISSUED AT 322 AM
CDT MON AUG 12 2013
Large scale upper level flow pattern shows very little change
through early this work week as a broad upper level vortex over
eastern Canada remains pretty much stationary...only starting to
lift out to the North Atlantic on Wednesday. Meanwhile...the
upper ridge over the Southwestern United States extending from Texas
northwestward toward Alberta remains essentially stationary.
This pattern will continue to produce the persistent northwest
upper level flow we have have seen for quite some time now over
Missouri and over much of the continent to our north and east. Two
weak but progressive short wave trofs embedded in this flow will
dive southeastward from the Northern High Plains into the area or
just to our southwest over Oklahoma Today and again later
Tuesday.
At the Surface and Lower levels Models are in now far better
agreement thorough Wednesday. All seem to focus most surface to
850 mb forcing over far Southwestern Missouri and just over NE
Okla/NW Ark with lower level Gulf moisture flux best to our
southwest also. Given this synoptic setup...expect the highest total
QPF values...around two inches to be over far southwestern Missouri
and extreme southeastern Kansas. Potential flash flooding will
therefore be a concern in this area and expect to issue a Flash
Flood Watch early this morning.
Through today and Tuesday...the potential for severe weather is not
high...but some stronger to marginally severe storms may be possible
as best surface based and MU cape values are also over far
southwestern Missouri. Zero to six KM bulk shear is running around
30 kts. The primary severe threat would be from winds.
Expect gradual clearing overnight Tuesday and early on Wednesday as
Canadian High Pressure and its associated Cold Front move southward
into the area.
.LONG TERM...(Thursday THROUGH Sunday) ISSUED AT 322 AM
CDT MON AUG 12 2013
The upper level vortex over Eastern Canada continues to slide
eastward into the North Atlantic and its associated upper trof
shifts southeastward toward the Appalachian ridge while weakening.
Upper ridging over the Rockies amplifies somewhat through the period
while sliding eastward into the High Plains.
After a Cold Front pushes south of the area Tuesday
night...Wednesday through Saturday will bring much drier and very
comfortable conditions as a seasonably strong surface Canadian high
pressure system behind this front sinks well south of the area.
Expect daytime highs to be in the upper 70s to lower 80s with
overnight lows in the lower upper 50s to lower 60s during this
time frame.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
ISSUED AT 645 AM CDT MON AUG 12 2013
Pilots can expect deteriorating flight conditions today as showers
and thunderstorms spread across the area.
Areas of MVFR to localized IFR conditions can be expected in areas
of morning fog and the heavier precipitation.
Precipitation may temporarily taper off later today but areas of fog
and lower ceilings will develop tonight.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Tuesday evening FOR MOZ055>058-066>071-
077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Tuesday evening FOR KSZ073-097-101.
&&
$$
MESOSCALE...Foster
SHORT TERM...Colucci
LONG TERM...Colucci
AVIATION...Foster
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
342 AM CDT Mon Aug 12 2013
.SHORT TERM...(Today through Wednesday Afternoon)
Issued at 342 AM CDT MON AUG 12 2013
A frontal boundary settling south though the Plains States of Iowa
and Nebraska Sunday set the stage for convective development to our
north that afternoon and evening. However, much of this activity
faded with the waning of the day; with only storms at the tail end
of the front, across south central Nebraska, able to bridge from the
heating of the day to the moisture transport of the nocturnal jet.
Speaking of which, this mornings jet, while not strong, has proved
sufficient enough to develop a growing area of thunderstorms in
north central Kansas. Current expectation, supported well by short
range models like the HRRR, are that the storms in north central
Kansas will congeal across central Kansas into a MCS which will
traverse our forecast area through the morning hours, making storms
likely during the morning commute in eastern Kansas and far western
Missouri. The MCV this could leave behind across western Missouri
this morning may keep cloud cover and showers percolating across our
forecast area through the day. This activity will be assisted by a
weak frontal boundary that will also be settling into northern
Missouri today. However, at this time areal coverage looks limited
enough by the late morning to afternoon hours to warrant carrying
only chance POPs. With the advancing baroclinic zone settling south
through the day, focus for continued convection will slowly settle
with it, generally along and south of the Missouri river by tonight,
with the focus continuing its southward trek through Tuesday.
Otherwise, looking at temperatures for the next 36 hours, today will
feel a bit hot and humid in northeast Missouri --no morning rain or
cloud cover--, but areas back tot he west will both cloud cover and
rain to cope with, there have shaved a few degrees off the going
forecast on the Kansas-Missouri state line. Tuesday, will simply be
cool as the surface high behind the advancing front makes its
presents felt in earnest. Look forward to even nicer conditions in
the coming work days.
.LONG TERM...(Wednesday Evening through Sunday)
Issued at 342 AM CDT MON AUG 12 2013
Agreement among medium range models leads to a high confidence
forecast this period. The overall upper level pattern will feature
troughing over the Great Lakes and Northeastern CONUS through the
period with upper level ridging over the Rockies. This will leave
the local area in between those two main features and, under cool
northwest flow aloft. At the surface, cool Canadian high pressure
will drop south through the northern Plains and Upper Midwest
Tuesday night and move into the local area on Wednesday. This ridge
of high pressure will remain dominant over the area through the
second half of the work week and into the weekend keeping conditions
dry and temperatures below average. Highs Wednesday through Friday
will be nearly 10 degrees below average in the upper 70s to near 80.
Highs Saturday will warm a bit into the lower 80s and will further
warm Sunday with highs in the low to mid 80s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1206 AM CDT MON AUG 12 2013
Satellite imagery suggests convection which formed along the NE
portion of a weak cold front is in the process of forming the
anticipated MCS which will likely affect eastern KS and west central
MO shortly after sunrise. The HRRR has had the best consistency on
developing this activity and over the past several hourly runs it now
tracks the MCS in a more easterly track vs southeasterly. Given radar
trends which show the southwest portion of the MCS is tracking
southeastward I won`t be surprised if the MCS eventually ends up
tracking ese. Bottom line is the convection is looking more likely it
will affect all 3 terminals Monday morning with KMCI/KMKC having a
greater chance plus the risk for thunder. Believe cigs will drop to
just above MVFR criteria although a brief drop to MVFR is possible
early on when the MCS is likely to be stronger.
Winds will remain light through the forecast with the MCS likely
resulting in chaotic wind directions. Some question as whether or not the
weak IA/NE cold front will drift far enough southward to reach west
central MO. Not much of push behind the front but the 00z NAM is the
only model which fails to move the front that far south. Will side
with model consensus for now and move the front into west central MO
Monday evening.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Cutter
LONG TERM...73
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1217 AM CDT Mon Aug 12 2013
.SHORT TERM...(This Evening through Tuesday Afternoon)
Issued at 324 PM CDT SUN AUG 11 2013
Short term model guidance continues to suggest scattered convection
developing along surface boundary draped across central Nebraska and
northern Iowa this afternoon. However, more widespread convection
should develop across northwest Kansas and southwest Nebraska within
the next few hours as a potent shortwave begins to enter the Western
Plains.
For the local area, dry conditions will persist into the evening
hours, as soundings continue to indicate fairly dry air in the low
and mid-levels. Surface dew points have risen slowly over the
extreme western CWA as boundary layer flow has turned to the south,
but in the NERN CWA, dew points remain in the 50s. HRRR/RAP/NAM
suggest scattered convection slowly sinking southward towards the
MO/IA border towards midnight, but should dissipate before reaching
the area. We`ll have to monitor potential for the development of an
MCS over western Kansas which would then track east southeast toward
the CWA by daybreak.
Monday: What`s left of the Kansas MCS should track primarily over
southeastern Kansas and south central Missouri Monday morning. As
the upper shortwave moves though the area, additional showers may
develop further north along and ahead of the surface boundary which
will be slowly pushing to the south through the day. Temperatures
as a result will be a difficult forecast given the potential for cloud
cover and showers to significantly impact readings in some locations.
Monday night-Tuesday: Modest isentropic downglide behind a departing
shortwave should allow the area to dry out quickly Monday night with
high pressure moving into the Upper Midwest. By Tuesday we`ll
monitor the potential for a secondary shortwave to track southward
through the increasingly northwest flow aloft. Confidence low on
any impact to the CWA, thus will leave PoPs out of the forecast.
.LONG TERM...(Tuesday Evening through Sunday)
Issued at 324 PM CDT SUN AUG 11 2013
Confidence in the extended period is above average, with all signs
pointing to a prolonged period of dry weather and below normal
temperatures. This will be driven by persistent ridging across the
Rockies and downstream northwesterly flow and a sprawling surface
high across the Midwest. Minimal changes were made to model
consensus numbers in this high-confidence forecast, which will be
more characteristic of mid-September than mid-August.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1206 AM CDT MON AUG 12 2013
Satellite imagery suggests convection which formed along the NE
portion of a weak cold front is in the process of forming the
anticipated MCS which will likely affect eastern KS and west central
MO shortly after sunrise. The HRRR has had the best consistency on
developing this activity and over the past several hourly runs it now
tracks the MCS in a more easterly track vs southeasterly. Given radar
trends which show the southwest portion of the MCS is tracking
southeastward I won`t be surprised if the MCS eventually ends up
tracking ese. Bottom line is the convection is looking more likely it
will affect all 3 terminals Monday morning with KMCI/KMKC having a
greater chance plus the risk for thunder. Believe cigs will drop to
just above MVFR criteria although a brief drop to MVFR is possible
early on when the MCS is likely to be stronger.
Winds will remain light through the forecast with the MCS likely
resulting in chaotic wind directions. Some question as whether or not the
weak IA/NE cold front will drift far enough southward to reach west
central MO. Not much of push behind the front but the 00z NAM is the
only model which fails to move the front that far south. Will side
with model consensus for now and move the front into west central MO
Monday evening.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Dux
LONG TERM...Hawblitzel
AVIATION...MJ
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1121 PM CDT Sun Aug 11 2013
.UPDATE:
Issued at 958 PM CDT Sun Aug 11 2013
No significant changes made. Adjusted cloud cover upwards based on
thicker mid/high level deck advancing from KS and wrn MO.
Otherwise just minor adjustments to capture short term trends.
Overnight lows still look on track.
2%
&&
.SHORT TERM: (Through Late Tonight)
Issued at 313 PM CDT Sun Aug 11 2013
Low level flow is turning back around to the south across southern
and central Missouri. Already seeing cumulus spread up to near
California Missouri and points west-northwest. A weak low level jet
develops tonight which produces some decent moisture convergence at
850mb primarily over southern portions of the CWFA. It doesn`t look
like the forcing is strong enough to produce very widespread or
organized convection, however the RUC is showing about 900 J/KG CAPE
in the region of moisture convergence, and the CAPE is fairly tall
extending up to 35,000ft. Certainly can`t rule out isolated-widely
scattered showers and thunderstorms over southeast Missouri and
possibly parts of east central and central Missouri as well, though
the lift drops off further north. Lows will be warmer tonight due
to the increasing cloud cover and southerly flow.
Carney
.LONG TERM: (Monday through Next Sunday)
Issued at 313 PM CDT Sun Aug 11 2013
Main concern continues to be thunderstorms chances early this week.
Scattered thunderstorms may be ongoing over the eastern Ozarks into
southern Illinois early Monday on the nose of a veering low level
jet. Better chance of storms will be focused along a cold front
that enters the northern CWFA early in the day and moves slowly
south through the day. Atmosphere will become increasingly
unstable along and ahead of the front with MLCAPEs around 1,000
J/kg with some weak CIN. This should be enough to generate
scattered thunderstorms given weak large scale ascent from a
passing shortwave. There may be a few strong storms that could
producing some gusty winds given the relatively dry low-mid levels
seen on the forecast soundings, though deep layer shear of only
25-30 knots will limit overall severe threat.
Not too many changes to previous thinking that rain chances will
diminish from north to south on Monday Night and Tuesday as the
front slowly moves south into the Mid South. Still have a dry
forecast going mid to late week as an impressive surface ridge
creeps southward through the area. Easterly low level flow and
850mb temperatures around 10C should keep temperatures below mid
August normals from Wednesday into Friday. Latest runs of the
GFS/ECMWF do agree that an upper trough will deepen over Missouri
and Illinois by Saturday. There will be Gulf moisture drawn
northward ahead of this trough, though any rain looks like it will
stay just south and east of us next weekend. 850mb temperatures
will warm into the mid-teens causing temperatures to climb closer
to normal by next weekend.
Britt
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1108 PM CDT Sun Aug 11 2013
Low-mid level cloudiness will spread nwd into the taf sites late
tonight as moisture spreads nwd. Could not rule out isolated
convection towards morning in COU and the St Louis metro
area...but the better chance should occur Monday afternoon with
the approach of an upper level disturbance from the west and a
cold front from the north. There should be at least scattered
showers and thunderstorms on Monday and will include either vcts
or prob30 in the tafs for tsra. Mainly a light sely sfc wind late
tonight...then the wind will veer around to a w-swly direction by
Monday afternoon...and a w-nwly direction Monday evening after
fropa.
Specifics for KSTL: Low-mid level cloudiness will advect nwd into
STL late tonight. There could be a few showers or thunderstorms
already towards morning...but may leave the STL taf forecast dry
until Monday afternoon. Light sely sfc wind will increase to 7 kts
on Monday...and veer around to a wly direction Monday afternoon
and a nwly direction Monday night.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
848 PM MDT TUE AUG 13 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
ALL BUT A TINY AREA OF CONVECTION HAS EXITED THE AREA TO THE EAST
INTO NORTH DAKOTA.
ONLY CHANGE FOR THIS UPDATE WAS TO ENHANCE POPS FOR THIS EVENING
AND TOMORROW MORNING. LATEST HRRR SHOW SOME SHOWERS ENTERING THE
AREA FROM THE WEST BY 4Z WITH SCATTERED REMNANTS PERSISTING
THROUGH 15Z ACROSS THE CWA. THIS DEPICTION IS IN GENERAL AGREEMENT
WITH SCATTERED ACTIVITY DEPICTED BY THE LOWER RES GFS AND EC
MODELS. SHOWER ACTIVITY IS RELATED TO A WEAK SHORTWAVE FEATURE
OVER WESTERN MT SEEN IN 500MB HEIGHT ANALYSES. THIS FEATURE MAKES
SLOW PROGRESS THROUGH THE MORE GENERAL RIDGE PATTERN AND PRODUCES
AN AREA OF WEAK LIFT AHEAD OF IT AS SEEN IN Q-VECTOR CONVERGENCE.
ONCE THIS FEATURE MAKES ITS WAY INTO NORTH DAKOTA BY LATE
WEDNESDAY..THE RIDGE WILL AGAIN DOMINATE GIVING MUCH WARMER AND
DRYER CONDITIONS THURSDAY.
PREVIOUS DISCUSSION...
WARM AND HUMID CONDITIONS HAVE CONTRIBUTED TO ISOLATED
THUNDERSTORMS WITH HEAVY RAIN TODAY. ONE EXAMPLE WAS 2.8" IN
SOUTHWEST DANIELS COUNTY.
SHOWERS PRESENTLY MOVING SE INTO ROOSEVELT COUNTY BUT ATMOSPHERE IS
UNSTABLE TO THE SOUTH WITH CAPE ABOUT 1000 J/KG AND DEWPOINTS IN THE
UPPER 50S TO LOW 60S. CERTAINLY RIPE CONDITIONS FOR HEAVY RAIN. RUC
AND HRRR CONTINUE TO SHOW THIS INTO THE EVENING HOURS MAINLY IN THE
EASTERN ZONES. THREAT SHOULD END THEREAFTER.
ON WEDNESDAY...DIURNAL HEATING WILL SPARK SHOWERS AND THUNDERSTORMS
AGAIN AS UPPER LEVELS REMAIN UNSETTLED WITH LOW LEVEL WARMTH AND
HUMIDITY. NOT CONFIDENT ENOUGH TO PIN-POINT WHERE HEAVY RAINS WILL
OCCUR AND DIDN/T FEEL COMFORTABLE TO BROADBRUSH THIS. SMALL HAIL AND
GUSTY WINDS ARE ALSO POSSIBLE BUT AGAIN DID NOT WANT TO
BROADBRUSH...AND IT/S ALREADY MENTIONED IN THE HWO.
BY THURSDAY...THE UPPER RIDGE BUILDS IN AND SUPPRESSES CONVECTION.
WITH MORE SUNSHINE...TEMPERATURES WILL BE WARMER. AIRMASS WILL BE
MORE HUMID OVER THE EASTERN ZONES BUT ANY THUNDERSTORM DEVELOPMENT
WILL BE OVER THE DAKOTAS. TFJ
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
A GOOD CHUNK OF THE PREVIOUS FORECAST STILL STANDS... BUT A COUPLE
PLACES NEEDED TWEAKING. FIRST... OVERNIGHT LOWS POST FRIDAY RIDGE
NEEDED TO BE DRUG DOWN AS THEY WARMED FAR TOO FAST FOR SOUTHWEST
FOLLOWED BY ZONAL FLOW ALOFT THROUGH EARLY NEXT WEEK. ALSO...
ACTED TO STRIP OUT ZERO POPS FOR THE SAME TIME PERIOD AS
VARIABILITY BEGINS TO CREEP INTO THE FORECAST POST SUNDAY AMONG
OPERATIONAL EC VERSUS ITS ENSEMBLE MEMBERS... WHILE NO REAL
ANALOGS FROM THE PAST 60 DAYS ARE YET AVAILABLE FOR THESE PERIODS.
GAH
PREVIOUS LONG TERM DISCUSSION...
THE LONG TERM FORECAST PERIOD BEGINS WITH A STRONG UPPER LEVEL
RIDGE IN PLACE WITH ITS AXIS DIRECTLY THROUGH NORTHEAST MONTANA.
EXCELLENT MODEL AGREEMENT IN KEEPING THE ENTIRE CWA CONSEQUENTLY
DRY. THIS WILL ALLOW THE HOTTEST TEMPERATURES OF THE SUMMER SEASON
TO FINALLY ARRIVE...TOPPING OUT IN THE LOW TO MID 90S...ALTHOUGH
SOME NUMERICAL GUIDANCE SUGGESTS THAT EVEN THIS MAY BE TOO
CONSERVATIVE FOR FRIDAY AND SATURDAY HIGH TEMPERATURES. FOR NOW
FELT IT WAS BEST TO SHOW A GRADUAL INCREASE UNTIL MORE MODEL
CONSENSUS IS EVIDENT.
WITH A COOL FRONT SET TO MOVE THROUGH THE AREA ON SATURDAY
NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE ON THE HEELS
OF SOME MUCH AWAITED NORTHWESTERLY SURFACE WINDS UNDER
SOUTHWESTERLY FLOW ALOFT COURTESY OF THE UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST COASTAL AREA. THIS UNSETTLED PERIOD SHOULD
REMAIN OVER THE REGION WHILE A SHORT WAVE TROUGH PUSHES THROUGH
THE AREA THROUGH MONDAY MORNING...WITH THE BEST CHANCES FOR PRECIP
FOCUSED FROM SATURDAY NIGHT THROUGH SUNDAY MORNING.
MONDAY AND BEYOND...STRONG SUMMER RIDGING FROM THE SOUTHWEST MOVES
IN AGAIN TO CUT OFF THE PRECIPITATION WITH TEMPERATURES WARMING
BACK UP INTO THE 90S.
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. LESS THAN VFR FLIGHT CONDITIONS ARE
POSSIBLE WITH THUNDERSTORMS OR OVERNIGHT FOG/MIST.
SCATTERED SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE TONIGHT.
AMENDMENTS MAY BE NEEDED. AS USUAL...BRIEF VISIBILITY
OBSCURATION AND SUDDEN GUSTY WINDS ARE POSSIBLE NEAR ANY
THUNDERSTORM.
FOG: WHILE CHANCES ARE NOT HIGH ENOUGH TO DIRECTLY INCLUDE IN THE
TAFS...A SMALL CHANCE FOR FOG DOES EXIST AT KOLF OR KSDY TONIGHT.
FOG IS MOST POSSIBLE NEAR THE EXCESS OF MOISTURE FROM SHOWERS
EARLIER IN THE EVENING. BEST WINDOW FOR FOG WOULD BE BETWEEN 08Z
AS WINDS DROPS OFF THROUGH 13Z RIGHT AFTER SUNRISE.
AREA WINDS: EXPECT EASTERLY WINDS LIGHT TO 10 KTS.
GAH/SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
254 PM MDT Mon Aug 12 2013
.DISCUSSION...
Tonight through Wednesday...Overall pattern has changed little
from Sunday. The airmass is a bit more unstable this afternoon
with CAPE values of 1000 to 2000 J/kg across the northern portion
of the county warning area. Shear values, though not overly
impressive, have also increased from earlier this morning and with
high precipitable water, the result is thunderstorm development.
The weak steering flow aloft will make very slow movers with these
storms and heavy rain will be the primary threat (although some
hail cannot be ruled out). HRRR and RUC analysis continue to
develop thunderstorms over Great Falls as late as 04 to 05z. Drier
conditions over southwest Montana will translate to isolated
thunderstorms this evening. Enough instability will exist Tuesday
afternoon to allow isolated to scattered thunderstorms to develop
again though areal coverage should be less. Rising H5 heights
Wednesday will herald the beginning of a drier and warmer regime.
Temperatures will be near or slightly above seasonal averages.
Emanuel
Wednesday Night through Monday...Medium range forecast remains
relatively unchanged tonight. Models are in good agreement from
mid-week until early in the weekend and indicate that an upper level
ridge will be over the Rocky Mountains for a very warm and generally
dry forecast period. Model consensus for the weekend through early
next week remains elusive. Models agree that the ridge will be
pushed eastward on Saturday as a broad upper level trough moves
inland along the west coast. Beyond Saturday, models set up a
roughly zonal flow aloft but bring multiple and frequent short waves
over the region. Unfortunately, the wave phase and speed differ
markedly between the models and significant disagreement with regard
to pops/clouds/weather timing arises. Am sticking with a solution
that trends temperatures slightly cooler and increases pops toward
climatology for the weekend through Monday. mpj
&&
.AVIATION...
UPDATED 1740Z.
Expect generally VFR conditions. Scattered showers/thunderstorms are
expected to develop over southwest Montana by mid-afternoon then
spread northeast later in the afternoon and evening. A few
thunderstorms could also develop over the plains by mid-afternoon.
There will be a threat of brief MVFR/IFR conditions in heavy rain
along with small hail with the thunderstorms except those over far
southwest Montana. Showers/thunderstorms are expected to diminish
over southwest Montana by dark and finally over the area from KHVR
to KLWT after midnight. Although not mentioned in the tafs there is
a small risk for patchy MVFR/IFR ceilings/visibilities in fog over
the plains late tonight and early Tuesday morning should skies clear
after the showers/thunderstorms. However some guidance does not
clear skies which would prevent fog formation. Blank
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 84 55 86 / 40 30 30 20
CTB 52 82 52 85 / 40 30 20 10
HLN 57 86 57 89 / 30 30 40 20
BZN 50 85 49 86 / 30 30 30 20
WEY 39 78 37 78 / 10 20 20 10
DLN 49 83 49 84 / 20 20 20 20
HVR 57 82 56 84 / 40 20 30 20
LWT 54 81 53 81 / 40 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING until 8 PM MDT this evening Beaverhead...
Jefferson...Madison.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS HASTINGS NE
940 PM CDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 934 PM CDT TUE AUG 13 2013
ONGOING CONVECTION CURRENTLY IN SW SOUTH DAKOTA/NW NEB IS PROGGED
TO REACH OUR NORTHERN CWA LATE TONIGHT/TOWARD WEDNESDAY MORNING
AND REORIENTED AND INCREASED POPS FOR WED TO ACCOUNT FOR THIS.
ALSO TONIGHT...INCLUDED PATCHY FOG FOR ALL AREAS WITH LIGHT
EASTERLY LLVL FLOW AND RECENT RAINFALL/MOISTURE. STILL SOME
UNCERTAINTY ON HOW LOW VSBYS WILL DROP AND WILL NEED TO MONITOR
TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
WE HAD A MESOSCALE CONVECTIVE VORTEX (MCV) TRACK ACROSS OUR FORECAST
AREA THIS MORNING INTO THE EARLY AFTERNOON HOURS. THIS BROUGHT
WIDESPREAD RAINFALL TO OUR FORECAST AREA AND HAS WORKED OVER THE
ATMOSPHERE ENOUGH THAT ADDITIONAL PRECIPITATION THIS EVENING INTO
TONIGHT IS UNLIKELY. THE CONVECTION THAT TRACKED THROUGH OUR AREA
HAS NOW PASSED SOUTH INTO CENTRAL KANSAS AND NEW STORMS HAVE ALSO
FORMED TO OUR WEST OVER THE HIGH PLAINS OF WESTERN NEBRASKA.
THE WESTERN NEBRASKA THUNDERSTORMS HAVE FORMED ALONG THE LEADING
EDGE OF THE NEXT SHORTWAVE THAT IS TRACKING SOUTHEAST FROM EASTERN
WYOMING/SOUTHWEST SOUTH DAKOTA INTO WESTERN NEBRASKA. DEEP MOISTURE
CONVERGENCE AND AFTERNOON DESTABILIZATION IS ALSO MAXIMIZED ACROSS
WESTERN NEBRASKA INTO THE BLACK HILLS AND THIS IS WHERE ADDITIONAL
THUNDERSTORMS ARE EXPECTED TO FORM THIS EVENING. THIS IS A WEAKLY
SHEARED ENVIRONMENT AND STORM PROPAGATION WILL GENERALLY BE A SLOW
DRIFT TO THE SOUTH...WHICH SHOULD KEEP THE WESTERN STORMS JUST TO
THE WEST OF OUR FORECAST AREA TONIGHT. THERE IS AN OUTSIDE CHANCE OF
OUR WESTERN ZONES SEEING A PREDAWN SHOWER/THUNDERSTORM SHOULD THE
BLACK HILLS CONVECTION MAKE IT THIS FAR SOUTHEAST. HOWEVER...MOST
FORECAST MODEL DATA KEEPS ALL CONVECTION WEST OF OUR FORECAST AREA
TONIGHT AND THUS WE WILL KEEP ALL ZONES DRY TONIGHT...WHILE KEEPING
AN EYE ON THE WEST FOR THE POSSIBILITY OF NEEDING TO THROW SOME POPS
IN THE FORECAST DEPENDING ON FUTURE RADAR TRENDS.
THERE IS SOME POTENTIAL OF FOG TONIGHT GIVEN THE RECENT WIDESPREAD
RAINFALL. HOWEVER...FORECAST MODELS ARE MIXED ON FOG POTENTIAL WITH
THE HRRR MORE FAVORABLE FOR FOG WHILE THE SREF WOULD NOT GIVE US ANY
FOG. ULTIMATELY FOG WILL LARGELY HINGE ON CLOUD COVER AND SUBSEQUENT
COOLING. HAVE LEFT FOG OUT OF THE FORECAST FOR NOW...BUT SHOULD WE
CLEAR OUT AND REMAIN CLEAR THROUGH MOST OF THE NIGHT...THEN COOLING
MIGHT BE ADEQUATE FOR SOME AREAS OF FOG EARLY WEDNESDAY MORNING.
WEDNESDAY...A SHORT WAVE TROUGH WILL TRACK SOUTHEAST ACROSS WESTERN
NEBRASKA. INSTABILITY AND DEEP LAYER SHEAR WILL BE FAIRLY WEAK TO
MODEST AT BEST AND THUS AM NOT EXPECTING SEVERE WEATHER...BUT CAN
NOT RULE OUT A COUPLE OF STRONG THUNDERSTORMS IN ASSOCIATION WITH
PEAK AFTERNOON HEATING. THE BEST CHANCE OF THUNDERSTORMS WILL BE
ACROSS OUR WESTERN ZONES AND TO THE WEST OF OUR FORECAST AREA IN
ASSOCIATION WITH THE APPROACHING SHORTWAVE. TEMPERATURES WILL REMAIN
COOL FOR AUGUST DUE TO A CONTINUATION OF THE COOL AIRMASS
OVERHEAD...CLOUDS...AND POSSIBLE PRECIPITATION. HIGHS WILL GENERALLY
BE IN THE UPPER 70S TO LOWER 80S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
THE MAIN HIGHLIGHTS OF THIS 6-DAY PERIOD ARE A CONTINUATION OF
CHALLENGING SHOWER/THUNDERSTORM CHANCES IN THE WED NIGHT THROUGH
FRIDAY TIME FRAME WHICH MIGHT EVEN FEATURE A STRONG-SEVERE STORM
THREAT CENTERED ON THURSDAY...FOLLOWED BY WHAT APPEARS TO BE A
PREDOMINANTLY DRY WEEKEND...AND THEN A RETURN TO VERY UNCERTAIN
RAIN CHANCES IN THE SUNDAY NIGHT-TUESDAY TIME FRAME AS THE PATTERN
CHANGES A BIT. ITS BEEN A TOUGH GO OF IT LATELY TRYING TO
DETERMINE HOW HARD TO HIT...OR BACK OFF...POPS EVEN IN THE FIRST
24 HOURS...SO THESE UNCERTAINTIES CONTINUE TO BE MAGNIFIED EVEN IN
THE DAY 2-3 TIME FRAME. OF HIGHER CONFIDENCE IS THAT A FAIRLY
REMARKABLE RUN OF SUB-90 DEGREE TEMPS WILL CONTINUE...WITH THE
MAJORITY OF THE CWA FORECAST TO TOP OUT IN THE LOW-MID 80S DURING
THIS TIME FRAME...WITH KS ZONES AS USUAL MOST FAVORED TO REACH
UPPER 80S ON A FEW DAYS. AS FOR LOW TEMPS...EVERY NIGHT IS
EXPECTED TO BE FAIRLY SIMILAR AND RATHER UNIFORM ACROSS THE
CWA...EITHER IN THE LOW OR MID 60S.
STARTING OFF WEDNESDAY EVENING/NIGHT...GAVE A BEST-STAB AT TWO
6-HOUR POP BLOCKS HEAVILY BASED ON MET/MAV GUIDANCE BLEND...WITH
THE EVENING PERIOD FEATURING 20S-40S...AND THE LATE NIGHT PERIOD
RANGING FROM ONLY 20S FAR WEST TO 50S IN EASTERN-MOST NEB ZONES.
IN OTHER WORDS...THERE IS A DECENT CHANCE THAT PARTS OF THE CWA
WILL SEE RAIN...BUT CONFIDENCE IN TIMING/PLACEMENT PRECLUDES
LIKELY POPS ANYWHERE YET. ON THE LARGE-SCALE ALOFT...LEGITIMATE
NORTHWEST-FLOW IS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN A
RIDGE AXIS EXTENDING NORTHWARD ACROSS THE ROCKIES FROM NORTHERN
MEXICO INTO SOUTHWEST CANADA...AND A BROAD TROUGH ANCHORED OVER
SOUTHEAST CANADA/THE NORTHEAST CONUS. ON A MORE LOCAL/REGIONAL
LEVEL...THE CWA IS PROGGED TO REMAIN UNDER/NEAR THE MAIN TRACK OF
LOW-AMPLITUDE SHORTWAVE TROUGHS RIPPLING THROUGH THE NORTHWEST
FLOW. STARTING OFF RIGHT AWAY WED EVENING AT 00Z/7PM...ITS
EXPECTED THAT AT LEAST A SMALL PART OF THE CWA SHOULD BE SEEING
ACTIVITY PERSISTING FROM THE LATE AFTERNOON HOURS...ALTHOUGH MODEL
QPF/REFLECTIVITY FIELDS VARY CONSIDERABLY ON THE MOST FAVORED
AREA. AS THE NIGHT WEARS ON...THERE IS A DECENT SIGNAL FOR WARM
AIR ADVECTION/MOISTURE TRANSPORT IN THE 850-700 MILLIBAR
LAYER...WITHIN THE AXIS OF A MODEST 20+KT SOUTHWESTERLY LOW LEVEL
JET. PER THE 12Z/18Z NAM AND LAST FEW SREF RUNS...THIS WOULD FAVOR
EASTERN ZONES FOR THE HIGHEST LATE NIGHT POPS...WHILE THE
ECWMF/GFS WOULD MORE-SO FAVOR CENTRAL/SOUTHWEST ZONES. AS FOR
THUNDERSTORM INTENSITY...ALTHOUGH NOT EXPECTING A WIDESPREAD
NOCTURNAL SEVERE THREAT...CERTAINLY A FEW STRONG TO MARGINALLY
SEVERE STORMS WITH MAINLY A HAIL/LOCALLY HEAVY RAIN THREAT CANNOT
BE RULED OUT GIVEN MUCAPE INCREASING TO AT LEAST 500-1000 J/KG IN
THE PRESENCE OF AROUND 25KT OF DEEP LAYER SHEAR.
THURSDAY/THURSDAY NIGHT...THIS 24 HOURS WOULD APPEAR TO CONTAIN
THE OVERALL-HIGHEST THREAT OF SEVERE STORMS DURING THE NEXT
SEVERAL DAYS...ALTHOUGH THE JURY IS STILL OUT ON WHETHER IT WOULD
BE MORE LOCALIZED OR MORE WIDESPREAD. CERTAINLY WOULD NOT BE
SURPRISED TO SEE THE UPCOMING SPC DAY 2 OUTLOOK INTRODUCE A SLIGHT
RISK FOR ALL/PART OF THE CWA...MAINLY FOR THE AFTERNOON/EVENING
HOURS. IN THE BIG PICTURE...SEASONABLY STRONG/SHARP NORTHWEST FLOW
STRENGTHENS AB IT...AS MODELS ARE IN DECENT AGREEMENT IN DRIVING A
BIT STRONGER/ORGANIZED SHORTWAVE TROUGH SOUTHWARD OUT OF WESTERN
SD ACROSS THE HEART OF CENTRAL NEB/KS. FOR THE MORNING
HOURS...KEPT POPS AT SLIGHT 20S EXCEPT 30S IN THE EAST WHERE
SEEMINGLY THE BEST CHANCE OF LINGERING OVERNIGHT CONVECTION WOULD
BE. THEN HAVE 30 POPS NEARLY ALL AREAS DURING THE AFTERNOON TO
ACCOUNT FOR THUNDERSTORM REDEVELOPMENT AND/OR
RE-INTENSIFICATION...ASSUMING OF COURSE THAT SUFFICIENT HEATING
CAN TAKE PLACE. ITS STILL TOO SOON TO TELL THOUGH WHETHER
POTENTIALLY VIGOROUS AFTERNOON ACTIVITY MAINLY DEVELOPS LOCALLY OR
MOVES IN FROM THE NORTHWEST. AT ANY RATE...THE 18Z NAM DEPICTS A
FAIRLY POTENT NORTHWEST FLOW SEVERE ENVIRONMENT WITH MIXED LAYER
CAPE 2000+ J/KG IN THE PRESENCE OF DECENT 30-40 KNOT DEEP LAYER
SHEAR...MAKING A FEW SUPERCELLS A POSSIBILITY IF THE MESOSCALE
FEATURES COME TOGETHER. FOR THURSDAY EVENING/NIGHT...KEPT 30-50
POPS GOING AREA-WIDE...HIGHEST IN THE FAR SOUTH. NOT ACCOUNTING
FOR POSSIBLE CONVECTIVE EFFECTS...BREEZES DURING THE DAY THURSDAY
ARE EXPECTED TO AVERAGE AROUND 10 MPH FROM THE SOUTH.
FRIDAY/FRIDAY NIGHT...THE LATEST NAM/GFS ARE IN GOOD AGREEMENT
AMPLIFYING THE WESTERN CONUS RIDGE EASTWARD OVER THE CENTRAL
PLAINS...RESULTING IN MODEST HEIGHT RISES AND NEARLY DUE-NORTHERLY
FLOW ALOFT. THIS SHOULD RESULT IN A LESS-FAVORABLE ENVIRONMENT FOR
THUNDERSTORM DEVELOPMENT. HOWEVER...KEPT THE MAJORITY OF THE CWA
WITH SLIGHT POPS DURING THE DAYTIME HOURS MAINLY TO ACCOUNT FOR
POSSIBLE DIURNAL-HEATING INDUCED CONVECTION...BUT LEFT FRIDAY
NIGHT DRY PER PREVIOUS FORECAST.
SATURDAY THROUGH SUNDAY...KEPT THE DRY FORECAST GOING CWA-
WIDE...AS SEEMINGLY-BENIGN NORTHERLY FLOW REMAINS IN PLACE ALOFT
TO THE EAST OF THE ROCKIES-CENTERED RIDGE AXIS. BOTH THE ECWMF/GFS
KEEP THE MAIN BRANCHES OF STRONGER FLOW ALOFT WELL NORTH NEAR THE
CANADIAN BORDER...AND ALSO IN THE SOUTHEAST STATES...WITH THE CWA
ALSO STAYING SAFELY NORTHWEST OF A STALLED...POSSIBLY RETROGRADING
CLOSED MID LEVEL LOW OVER THE SOUTHERN MO/AR AREA ADVERTISED MORE
SO BY THE ECMWF THAN THE GFS. NOT READY TO GUARANTEE A DRY WEEKEND
YET...BUT AT LEAST FOR NOW POPS HAVE BEEN KEPT IN THE SILENT 5-10
RANGE. GIVEN THAT THE AREA HAS SEEN VERY LITTLE IN THE WAY OF NON-
CONVECTIVE BREEZE LATELY...ITS WORTH NOTING THAT THE CURRENT
SUNDAY FORECAST ACTUALLY HAS SUSTAINED SOUTHERLY SPEEDS UP AROUND
15 MPH/GUSTS AROUND 20 MPH.
SUNDAY NIGHT THROUGH TUESDAY MARKS THE RETURN OF VARIOUS...LOW-
CONFIDENCE THUNDERSTORM CHANCES OF THE 20-30 PERCENT
VARIETY...THAT WILL UNDOUBTEDLY BE REFINED SEVERAL TIMES DURING
THE NEXT SEVERAL DAYS. FROM A GENERAL...SYNOPTIC SCALE
STANDPOINT...BOTH THE ECWMF/GFS BREAK DOWN THE RIDGE-DOMINATED
PATTERN FROM THE WEEKEND AND GRADUALLY BRINGS A QUASI-ZONAL
PATTERN AS ONE OR TWO FAIRLY LOW-AMPLITUDE SHORTWAVE TROUGHS OF
NOTE WORK INTO THE CENTRAL PLAINS FROM THE WEST. THIS SHOULD
SUPPORT A CONTINUED SURFACE PATTERN OF LIGHT BUT NOTICEABLY
SOUTHERLY BREEZES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 520 PM CDT TUE AUG 13 2013
THE MAIN CONCERN FOR THE TAF PERIOD IS THE POTENTIAL FOR FOG
TONIGHT...THEN TIMING OF THUNDERSTORMS ON WEDNESDAY. CONVECTION
REMAINS WELL WEST OF THE TERMINAL THIS EVENING AND GENERALLY
EXPECT THE DRY CONDITIONS TO PERSIST UNTIL WEDNESDAY AFTERNOON.
WITH WET GROUND AND DECREASING CLOUDS THIS EVENING...THERE IS SOME
POTENTIAL FOR FOG DEVELOPMENT AND MODELS ARE NOT IN COMPLETE ON
HOW DENSE FOG MAY BE AND HAVE JUST TRENDED WITH MVFR VSBYS TO
START. AN UPPER LEVEL DISTURBANCE WILL CROSS NEB ON WEDNESDAY CHCS
FOR TSTMS INCREASING AGAIN BY MID/LATE AFTN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...FAY
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
414 PM CDT MON AUG 12 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
THE MAIN ISSUES DURING THE NEXT 24 HOURS INCLUDE FICKLE
THUNDERSTORM CHANCES...ALONG WITH WHETHER OR NOT FOG TONIGHT MIGHT
END UP BEING IMPACTFUL IN SOME SPOTS.
20Z OBJECTIVE SURFACE ANALYSIS SHOWS A WEAK COLD FRONT STRETCHED
ACROSS KS FROM SOUTHWEST-NORTHEAST...WHILE TO THE NORTH OF THIS
BOUNDARY...THE MAJORITY OF THE CWA IS EXPERIENCING LIGHT BREEZES
RANGING FROM NEAR-CALM TO NO MORE THAN 5-10 MPH FROM THE EAST-
NORTHEAST UNDER THE INFLUENCE OF BROAD HIGH PRESSURE EXTENDING
WELL SOUTHWARD FROM CANADA. ALOFT...WATER VAPOR IMAGERY AND SHORT
TERM MODEL DATA SHOWS GENERALLY WEST-NORTHWEST FLOW ALOFT OVER THE
CENTRAL PLAINS...MORE WESTERLY UP AROUND 300 MILLIBARS..AND MORE
NORTHERLY FARTHER DOWN IN THE MID LEVELS 500/700 MILLIBARS. THIS
FLOW REGIME REMAINS ESTABLISHED BETWEEN A LARGE SCALE TROUGH OVER
THE GREAT LAKES/SOUTHEAST CANADA AREA...AND A RIDGE EXTENDING
NORTH-NORTHWEST INTO THE ROCKIES OUT OF THE TX/NORTHERN MEXICO
AREA. IN TERMS OF THE REGIONAL SCALE...THE MAIN LOW AMPLITUDE
DISTURBANCE OF INTEREST HAS PASSED ONTO THE EAST INTO
MO...ALTHOUGH SMALL RIBBONS OF CHANNELED VORTICITY ARE EVIDENT
EXTENDING BACK WEST-NORTHWEST ACROSS THE SOUTHERN CWA TOWARD THE
WY/NE/CO BORDER AREA PER LATEST OBJECTIVE MESO-ANALYSIS.
DESPITE WHAT VARIOUS MODELS WERE EARLIER-SHOWING...THE CWA HAS
REMAINED DRY ALL DAY IN THE WAKE OF THE EXTENSIVE CONVECTION
SUNDAY EVENING/EARLY THIS MORNING. VISIBLE SATELLITE REVEALS ONLY
A SCATTERED TO LOCALLY BROKEN FAIR WEATHER CUMULUS FIELD MAINLY IN
THE FAR NORTHERN/EASTERN/SOUTHERN COUNTIES...AND HIGH TEMPERATURES
ARE ON TRACK TO TOP OUT 82-85 NEARLY ALL AREAS.
FOR LATE THIS AFTERNOON INTO THIS EVENING...MODELS CONTINUE TO
STRUGGLE WITH THEIR INDIVIDUAL QPF FIELDS...AS SOME APPEAR TO
THINK THAT CONVECTION WILL BREACH A WEAK CAP LOCALLY. LEANING
TOWARD THE HIGHER-RES SOLUTIONS OF THE HRRR AND 4KM WRF
NMM/ARW...IT APPEARS RATHER UNLIKELY THAT ANYTHING WILL POP IN THE
NEXT 3-6 HOURS ESPECIALLY ACROSS THE CENTRAL/EASTERN CWA DUE TO
LACK OF FORCING AND LACK OF LOW-LEVEL CONVERGENCE...AS THE WEAK
CAP SHOULD HOLD DESPITE THE PRESENCE OF 1000-1500 J/KG 0-1KM MIXED
LAYER CAPE PER LATEST RUC ANALYSIS. AS A RESULT...THROUGH MIDNIGHT
HAVE CONFINED SLIGHT POPS TO MAINLY THE WESTERN 1/4 TO 1/3 OF THE
CWA...MAINLY TO ACCOUNT FOR THE SMALL POSSIBILITY THAT STORMS
CURRENTLY DEVELOPING IN WESTERN NEB...AND MAYBE EVENTUALLY IN
NORTHWEST KS AS WELL...MIGHT SLIP EASTWARD INTO THE CWA. GIVEN THE
CONTINUED WEAK DEEP LAYER SHEAR REGIME ONLY AROUND 20KT...AND
INSTABILITY FADING WITH TIME TONIGHT...THINK THE PROBABILITY OF
STRONG THUNDERSTORMS...LET ALONE SEVERE...IS QUITE LOW. AFTER
MIDNIGHT...UNCERTAINTY CONTINUES TO GROW...BUT WITH BOTH THE
LATEST HRRR AND 18Z NAM ADVERTISING SOME CONVECTION FLARING UP
MAINLY JUST NORTHWEST OF THE CWA LIKELY IN RESPONSE TO SOME SUBTLE
MID LEVEL THETA-E ADVECTION...AND OTHER MODELS SHOWING CONVECTION
LURKING IN OR NEAR KS ZONES...WENT AHEAD AND EXPANDED 20-30 POPS
TO INCLUDE ALL BUT A HANDFUL OF SOUTHEASTERN COUNTIES JUST IN
CASE. THE OTHER POTENTIAL ISSUE TONIGHT IS FOG. WHILE MET/MAV
GUIDANCE IS SUGGESTING ONLY SOME LIGHT FOG...THE 15Z SREF SUGGESTS
PERHAPS AN ENHANCED RISK OF VISIBILITY RESTRICTIONS BELOW 1 MILE
ESPECIALLY ACROSS THE SOUTHWEST 1/3 OF THE CWA LATE TONIGHT.
CERTAINLY THE VERY LIGHT EASTERLY FLOW REGIME AND RECENT RAINFALL
COULD HELP THE CAUSE OF FOG FORMATION...BUT GIVEN THAT FOG DID NOT
BECOME TOO MUCH OF AN ISSUE LAST NIGHT IN THE WAKE OF DEPARTING
CONVECTION WITH A SIMILAR WIND REGIME...DECIDED TO ONLY INTRODUCE
A PATCHY FOG MENTION CWA-WIDE FOR NOW LATE TONIGHT...AND DEFER TO
NEXT FEW SHIFTS TO MONITOR THE SITUATION AND RAMP UP FOG POTENTIAL
IF NECESSARY.
TURNING TO THE TUESDAY DAYTIME HOURS...THE QUESTIONS JUST CONTINUE
TO ARISE. TAKING VARIOUS MODEL QPF FIELDS AT FACE VALUE...THERE
COULD BE QUITE A BIT OF ONGOING CONVECTION DURING THE
DAY...ESPECIALLY ACROSS THE WESTERN HALF OF THE CWA...POSSIBLY AS
A CONTINUATION OF OVERNIGHT ACTIVITY MOVING IN...OR LOCAL
DEVELOPMENT RAMPING UP WITH DAYTIME HEATING...AS THE THERMODYNAMIC
STRUCTURE OF THE ATMOSPHERE SHOULD REMAIN SIMILAR TO TODAY WITH
WEAK CAPPING IN THE PRESENCE OF ROUGHLY 1000 J/KG OF CAPE. THE
MILLION DOLLAR QUESTION IS WHETHER NOT FORCING WILL BE STRONG
ENOUGH TO REALIZE THE POTENTIALLY WIDESPREAD CONVECTION ADVERTISED
BY SOME MODELS...OR WHETHER MODELS ARE OVER-DOING QPF AS SEVERAL
DID FOR TODAY. THERE SHOULD AT LEAST BE A FEW SUBTLE SHORTWAVE
TROUGHS PASSING THROUGH THE REGION PER MODEL VORTICITY
FIELDS...PRIMARILY PASSING ACROSS THE SOUTHWEST 1/2 OF THE CWA AND
POINT SOUTH. FOR NOW...DECIDED TO MAKE LITTLE CHANGE TO PREVIOUS
FORECAST WHICH ALREADY HAD POPS LOW AT NO MORE THAN 20-30
PERCENT...WITH THESE CHANCES COVERING MOST OF THE CWA IN THE
MORNING...AND THE ENTIRE AREA IN THE AFTERNOON. IF FORCING IS IN
FACT ENOUGH TO GENERATE WIDESPREAD CONVECTION...THEN NEXT SHIFT
MAY HAVE TO RAISE POPS NOTICEABLY ESPECIALLY IN WESTERN
AREAS...BUT AFTER SEEING HOW TODAY ENDED UP BONE-DRY THROUGH LATE
AFTERNOON...THINK IT WOULD BE UNWISE TO GET CARRIED AWAY WITH RAIN
CHANCES EVEN 12-24 HOURS OUT. AGAIN...NOT EXPECTING ANY SEVERE
STORMS...BUT A LOCALIZED STRONG STORM PROBABLY NOT OUT OF THE
QUESTION. OBVIOUSLY HIGH TEMPERATURES WILL BE HIGHLY DEPENDENT ON
THE COVERAGE...OR LACK THEREOF...OF DAYTIME CONVECTION...SO THERE
IS SOME UNCERTAINTY HERE TOO. GIVEN A SIMILAR LOW-LEVEL TEMP
REGIME...BLENDED THE COOLER PREVIOUS FORECAST FOR TOMORROW WITH
READINGS SIMILAR TO THOSE OBSERVED TODAY...WHICH RESULTS IN A
SLIGHT INCREASE TO PREVIOUS HIGHS AND NOW CALLING FOR 79-82 MOST
AREAS. BREEZES DURING THE DAY SHOULD AVERAGE ONLY 5-10 MPH FROM
THE EAST ASSUMING CONVECTIVE OUTFLOW DOESN/T GET TOO INVOLVED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
HE COOLER THAN NORMAL TREND WILL LIKELY CONTINUE THROUGH AT LEAST
SATURDAY...WITH PERHAPS A RETURN OF NEAR NORMAL HIGHS BY SUNDAY AND
MONDAY. WEAK SHORT WAVES WILL TRACK ACROSS OUR FORECAST AREA WITHIN
THE PERSISTENT UPPER LEVEL NORTHWESTERLY FLOW REGIME.
CONSEQUENTLY...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE ACROSS AT LEAST PORTIONS OF OUR FORECAST AREA OFF AND ON
AGAIN THROUGH MUCH OF THE PERIOD.
TUESDAY NIGHT THROUGH WEDNESDAY...A DECENT 500 MB VORT MAX/SHORT
WAVE WILL TRACK SOUTHEAST ACROSS THE HIGH PLAINS BRINGING A CHANCE
OF THUNDERSTORMS PRIMARILY TO AREAS WEST OF OUR FORECAST AREA.
HOWEVER...THERE IS GENERALLY A SLIGHT CHANCE THAT A FEW OF THESE
THUNDERSTORMS COULD TRACK INTO OUR WESTERN ZONES PRIMARILY WEST OF
HWY 281. INSTABILITY AND SHEAR ARE BOTH WEAK AND THUS ANY
THUNDERSTORMS THAT WORK INTO OUR AREA WILL LIKELY BE NON SEVERE.
TEMPERATURES WILL BE COOL FOR THIS TIME OF YEAR WITH THE UPPER LEVEL
JET STREAM TO OUR SOUTH.
WEDNESDAY NIGHT THROUGH FRIDAY...THIS SHOULD BE OUR BEST CHANCE AT
MORE WIDESPREAD THUNDERSTORM POTENTIAL ACROSS THE FORECAST AREA AS
A TRAIN OF SUCCESSIVE SHORT WAVE TROUGHS WORK THEIR WAY ACROSS THE
CENTRAL PLAINS. UPPER LEVEL SHEAR AND INSTABILITY WILL ALSO BE ON
THE INCREASE ESPECIALLY THURSDAY AFTERNOON THROUGH FRIDAY...WHICH
MAY RESULT IN A FEW STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. AT
THIS POINT...IT DOES NOT APPEAR TO BE A WIDESPREAD SEVERE
EVENT...BUT CAN NOT RULE OUT THE POSSIBILITY OF ISOLATED SEVERE
STORMS. TEMPERATURES WILL REMAIN RELATIVELY COOL...UPPER 70S TO
AROUND 80 DUE TO CLOUDS...POTENTIAL PRECIPITATION...AND MEAN MID
AND UPPER LEVEL JET POSITION.
SATURDAY AND SUNDAY...A BIT OF AN UPPER RIDGE IS PREDICTED TO WORK
INTO OUR FORECAST AREA THAT IF IT VERIFIES WOULD RESULT IN DRY
CONDITIONS THIS WEEKEND AND THEN WARMING TEMPERATURES TO NEAR NORMAL
BY SUNDAY.
SUNDAY NIGHT AND MONDAY...THE NEXT UPPER SHORT WAVE IS PROJECTED BY
BOTH THE 12Z GFS AND 12Z ECMWF TO MOVE INTO THE CENTRAL PLAINS. THIS
WILL RESULT IN AT LEAST SOME CHANCE OF THUNDERSTORMS...PARTICULARLY
ACROSS OUR WEST...ALTHOUGH THESE CHANCES MAY EVENTUALLY NEED TO BE
EXPANDED/RAISED SHOULD CURRENT FAVORABLE MODEL TRENDS CONTINUE.
ALLBLEND GIVES US NEAR NORMAL TEMPERATURES...AND LIKELIHOOD IS THAT
WE WILL LIKELY BE NO WARMER THAN NORMAL...AND WOULD NOT BE SURPRISED
IF MONDAY HIGHS GET LOWERED SOME WITH FUTURE FORECAST UPDATES.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1252 PM CDT MON AUG 12 2013
AT THIS TIME...THE ONLY NON-VFR TIME FRAME IN THE FORECAST IS A
PERIOD OF MVFR VISIBILITY THAT HAS BEEN INTRODUCED FROM 08Z-13Z
TONIGHT/EARLY TUESDAY MORNING TO COVER THE POSSIBILITY OF FOG
DEVELOPMENT GIVEN THE COMBINATION OF LIGHT EASTERLY FLOW AND
MOISTURE FROM RECENT RAINFALL. CONFIDENCE IS CERTAINLY QUITE LOW
ON THE LIKELIHOOD/MAGNITUDE OF FOG DEVELOPMENT...AND COULD
POTENTIALLY SEE IT BEING WORSE THAN CURRENTLY
ADVERTISED...ALTHOUGH AVAILABLE MODELS/GUIDANCE SUGGEST THAT MVFR
VISIBILITY IS A GOOD FORECAST COMPROMISE FOR NOW. OTHERWISE...THE
MAJORITY OF THE PERIOD HAS HIGH CONFIDENCE OF VFR CONDITIONS...WITH
ONLY THE SLIGHTEST CHANCE OF A SHOWER/THUNDERSTORM LATE THIS
AFTERNOON ONWARD...BUT THIS RISK APPEARS TOO LOW TO EVEN SUPPORT A
VICINITY THUNDERSTORM MENTION. SURFACE BREEZES WILL GENERALLY
PREVAIL FROM AN EASTERLY DIRECTION...WITH SUSTAINED SPEEDS
UNLIKELY TO EXCEED 7KT THROUGHOUT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
330 PM CDT MON AUG 12 2013
.SYNOPSIS...
ISSUED AT 330 PM CDT MON AUG 12 2013
THE 12Z H5 ANALYSIS FROM EARLIER THIS MORNING HAD A HIGH
AMPLITUDE RIDGE EXTENDING FROM THE NRN ROCKIES INTO THE YUKON AND
WESTERN PORTIONS OF THE NW TERRITORIES OF CANADA. FURTHER EAST...A
TROUGH OF LOW PRESSURE EXTENDED FROM CENTRAL QUEBEC SWD INTO THE
EASTERN GREAT LAKES. A STRONG SHORTWAVE WAS NOTED OVER WRN ONTARIO
WITH DECENT HT FALLS NOTED OVER CENTRAL AND EASTERN ONTARIO. HIGH
PRESSURE EXTENDED ALONG THE GULF COAST...WEST TO NRN MEXICO. SEVERAL
EMBEDDED SHORTWAVES WERE NOTED ACROSS THE INTERMOUNTAIN WEST...MOST
NOTABLY IN CENTRAL AZ AND NRN UT. CLOSER TO WESTERN AND NORTH
CENTRAL NEBRASKA...MORNING STRATUS HAS BURNED OFF...BUT WITH A WEAK
CAP IN PLACE...ABUNDANT CU HAS DEVELOPED OVER THE PAST
HOUR...ESPECIALLY ALONG THE HIGHWAY 61 CORRIDOR FROM HYANNIS TO
IMPERIAL...INVOF OF WESTWARD MOVING SURFACE BOUNDARY. TEMPERATURES
AS OF 2 PM CDT...WERE IN THE UPPER 70S AND LOWER 80S.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 330 PM CDT MON AUG 12 2013
THE MAIN FORECASTING CHALLENGE OVER THE NEXT 24 HOURS
IS PRECIPITATION CHANCES. THE NEAR TERM MODELS THIS MORNING...MOST
NOTABLY THE GFS AND NAM SOLNS DIDN`T INITIALIZE WELL WITH A MCV
NOTED OVER CENTRAL NEBRASKA. THIS FEATURE WAS WAY OVERDONE THIS
MORNING...AND LENDS A LOT OF DOUBT AS TO HOW THESE MODELS WILL
HANDLE ANY CONVECTION THIS EVENING. THE 09Z SREF...INITIALIZED
BETTER AND WAS NOT OVERLADEN WITH QPF LIKE THE GFS AND NAM SOLNS
WERE. WITH THIS IN MIND...POPS WERE TRIMMED BACK IN THE EASTERN
ZONES FOR TONIGHT...AS THE BULK OF ANY PCPN WILL BE FOCUSED INVOF
OF THE SURFACE BOUNDARY ACROSS THE WESTERN CWA. DEEP LAYER SHEAR
REMAINS WEAK OVER THE WESTERN HALF OF THE FORECAST AREA...SO ANY
THREAT FOR SEVERE STORMS IS VERY MINIMAL ATTM. OVERNIGHT
TONIGHT...THE MODELS ARE INDICATING THE DEVELOPMENT OF A WEAK LOW
LEVEL JET ACROSS THE PANHANDLE AND WESTERN CWA...SO THE THREAT FOR
STORMS...SHOULD BE MINIMAL IN THE EASTERN CWA. BETTER CHANCES FOR
PCPN ARRIVE EARLY TUESDAY MORNING AS A DECENT SHORT WAVE LIFTS
FROM THE CENTRAL ROCKIES EWD INTO KS AND NEBRASKA. SREF
PROBABILITIES FOR MEASURABLE PCPN APPROACH 90 PERCENT IN THE
CENTRAL AND SOUTHWESTERN FORECAST AREA BY TUESDAY AND RAISED POPS
WEST OF HIGHWAY 83. LIKE TODAY...THE THREAT FOR SEVERE STORMS WILL
BE SMALL GIVEN THE VERY WEAK CAPPED ENVIRONMENT AND WEAK DEEP
LAYER SHEAR. SKIES TOMORROW WILL BE PARTLY TO MOSTLY
CLOUDY...WHICH WILL KEEP HIGHS IN THE 70S. LOWS TONIGHT WILL BE IN
THE UPPER 50S TO AROUND 60 UNDER PARTLY TO MOSTLY CLOUDY SKIES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 PM CDT MON AUG 12 2013
THIS PERIOD WILL START OFF WITH AN UPPER LEVEL OVER THE
INTERMOUNTAIN WEST AND AN UPPER TROUGH PASSING THROUGH THE GREAT
LAKES REGION. THIS WILL LEAVE NEBRASKA UNDER NORTHWEST FLOW ALOFT
AND SURFACE HIGH PRESSURE OVER THE WESTERN GREAT LAKES. THE SURFACE
HIGH WILL SLOWLY DRIFT SOUTHEAST INTO THE OHIO RIVER VALLEY THROUGH
THE REST OF THE WEEK...WHILE THE UPPER RIDGE AXIS IN THE WEST SLOWLY
APPROACHES THE HIGH PLAINS.
A FEW THUNDERSTORMS MAY BE UNDERWAY ACROSS CENTRAL AND WESTERN
NEBRASKA COME TUESDAY EVENING. THE BEST CHANCE LOOKS TO BE IN THE
WESTERN FORECAST AREA DURING THE EVENING...BUT THEN SHIFTS TO THE
NORTHEAST LATE IN THE NIGHT. DEEP SHEAR LOOKS RATHER LIMITED TUESDAY
NIGHT...SO SEVERE CHANCES LOOK SLIM. AN UPPER LEVEL WAVE WILL MOVE
THROUGH THE AREA WEDNESDAY NIGHT...WITH THUNDERSTORM ACTIVITY
STARTING IN THE WEST AND SHIFTING EAST OVERNIGHT. GFS HAS BETTER
SHEAR ON WED AFTERNOON/EVENING...HOWEVER BELIEVE ITS OVERDONE A BIT
BASED ON INPUT FROM THE NAM AND SREF MODELS. STILL...BELIEVE
WEDNESDAY NIGHT HAS THE BEST CHANCE FOR PRECIPITATION ACROSS THE
AREA DURING THIS PERIOD. MODELS INDICATE ANOTHER WAVE MAY MOVE
THROUGH THE REGION ON THURSDAY...BUT WITH MOST OF THE ACTIVITY IN
THE EAST.
THE UPPER RIDGE AXIS SHIFTS INTO THE HIGH PLAINS OVER THE
WEEKEND...ALLOWING TEMPS TO INCREASE SOMEWHAT...WITH HIGHS IN THE
MID 80S TO NEAR 90. AFTER A BREAK FROM THUNDERSTORM ACTIVITY FR DAY
NIGHT THROUGH SUNDAY...MODELS INDICATE THERE MAY BE ANOTHER
DISTURBANCE MOVING THROUGH THE REGION BY SUNDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1228 PM CDT MON AUG 12 2013
A TRICKY AVIATION FORECAST IS IN THE CARDS OVER THE NEXT 24 HOURS
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. WEAK MID LEVEL FLOW AND
THE LACK OF A FRONTAL BOUNDARY WILL MAKE IT DIFFICULT TO PINPOINT
TIMING AND LOCATION OF THUNDERSTORMS TONIGHT. BOTH THE NAM AND GFS
SOLNS HAD SOME SIGNIFICANT INITIALIZATION ISSUES THIS MORNING AND
RELIED HEAVILY ON THE SREF AND HIRES RUC SOLNS FOR THE 18Z TAF
FCSTS. THAT BEING SAID...THINKING HERE IS THAT MID AND UPPER LEVEL
CLOUDINESS WILL BE ON THE INCREASE LATER THIS AFTERNOON AND THIS
EVENING AS CONVECTION DIES OFF TO THE WEST OF THE FORECAST AREA.
COVERAGE OF ANY ISOLATED TSRAS THIS EVENING WILL BE TOO SPARSE TO
INCLUDE IN THE 18Z TAFS. HOWEVER...HIGHER CONFIDENCE IN
THUNDERSTORMS CREEPS INTO THE FORECAST ON TUESDAY MORNING AS THE
SREF...GFS AND NAM SOLNS BEGIN TO COME INTO BETTER AGREEMENT WITH
TSRA CHANCES ACROSS WESTERN NEBRASKA. WILL HANDLE THIS THREAT FOR
TSRAS WITH A PROB 30 GROUP AT BOTH TERMINALS FOR TUESDAY MORNING.
CIGS OVER THE NEXT 24 HOURS WILL GENERALLY RANGE FROM 6000 TO 15000
FT AGL. THE EXCEPTION WILL BE AT THE KVTN TERMINAL...AS SOME 1500 TO
2500 FT AGL CIGS ARE POSSIBLE AT THE KVTN TERMINAL THROUGH MID
AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...KNUTSVIG
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1228 PM CDT MON AUG 12 2013
.SYNOPSIS...
ISSUED AT 302 AM CDT MON AUG 12 2013
THUNDERSTORM ACTIVITY ASSOCIATED WITH DEEP MOISTURE AND A BELT OF
STRONG WESTERLIES AT 300 MB SHOULD CONTINUE THROUGH WEDNESDAY
NIGHT. THEREAFTER...WINDS ALOFT BECOME NORTH PRODUCING SUBSIDENCE.
RAIN CHANCES WILL DIMINISH AS THE ATMOSPHERE DRIES OUT.
&&
.UPDATE...
ISSUED AT 1038 AM CDT MON AUG 12 2013
JUST UPDATED THE ONGOING FORECAST TO TAKE OUT MENTION OF
FOG...LOWER MAX TEMPS SLIGHTLY BASED ON TEMPERATURE TRENDS...AND
TRIMMED POPS FROM THE FORECAST IN THE EAST THIS AFTERNOON. A
FAIRLY IMPRESSIVE AREA OF FOG DEVELOPED OVER PORTIONS OF NORTH
CENTRAL...CENTRAL AND SOUTHWESTERN NEBRASKA EARLIER THIS MORNING.
SOME VISBYS DOWN TO A QUARTER MILE OR LESS WERE NOTED...ESPECIALLY
IN RIVER VALLEYS AND LOW LYING AREAS. IN PARTICULAR, THE HIGHWAY
20 CORRIDOR FROM VALENTINE TO ONEILL AND ALONG THE INTERSTATE 80
AND HIGHWAY 26 CORRIDORS FROM CHAPPELL TO OGALLALA TO NORTH
PLATTE...AND FROM LISCO TO OGALLALA. THIS FOG IS EXPECTED TO
TOTALLY BURN OFF BY 11 AM CDT (10 AM MDT). FORECAST HIGHS WERE
MODIFIED DOWNWARD SLIGHTLY FOR TODAY IN THE EAST AS MOSTLY CLOUDY
SKIES WILL CONTINUE THROUGH LATE MORNING. FINAL CHANGES WERE MADE
TO PRECIPITATION CHANCES FOR THIS AFTERNOON. ATTM HAVE LITTLE
CONFIDENCE IN THE NAM SOLUTION AS IT INITIATED AN AREA OF
THUNDERSTORMS ACROSS THE CENTRAL AND WESTERN CWA THIS MORNING.
RELIED MORE ON THE HI RES RUC...WHICH DEVELOPS ISOLATED TSRAS IN
THE CENTRAL AND WEST LATER THIS AFTERNOON. WITH NO CAP NOTED IN
THE FORECAST AREA THIS SOLN SEEMS PLAUSIBLE LATER THIS AFTERNOON.
UPDATE ISSUED AT 702 AM CDT MON AUG 12 2013
AREAS OF FOG SOME DENSE CONTINUED TO DEVELOP OVER WESTERN NEBRASKA
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 302 AM CDT MON AUG 12 2013
MODELS IN FAIR AGREEMENT AND HAVE USED A BLEND FOR THE FORECAST. NAM
SOLUTIONS FOR SUNDAY WERE MUCH BETTER THAN GFS FORECAST SO WILL
TREND FORECAST TOWARDS NAM SOLUTIONS. FRONT CAME THROUGH WITH MUCH
COOLER AIR YESTERDAY ONLY MADE IT INTO THE 70S OVER NORTH CENTRAL
NEBRASKA. CLOUDS CLEARING OUT QUICKLY THIS MORNING. WILL SEE SOME
REBOUND IN TEMPERATURES WITH MOST AREAS SEEING 80S TODAY.
INSTABILITY THIS AFTERNOON AND A MID LEVEL WAVE MOVING SOUTH ACROSS
THE NORTHERN PLAINS WILL PROVIDE ENOUGH FORCING FOR THUNDERSTORM
DEVELOPMENT ACROSS THE NEBRASKA SANDHILLS MID TO LATE AFTERNOON.
THUNDERSTORMS ALSO EXPECTED TO DEVELOP ALONG STATIONARY BOUNDARY
ACROSS THE NEBRASKA PANHANDLE LATE AFTERNOON AND TO PUSH EAST OVER
NIGHT. TEMPERATURES FALLING INTO 50S FOR OVER NIGHT LOWS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 302 AM CDT MON AUG 12 2013
TUESDAY THROUGH WEDNESDAY NIGHT...
PERSISTENT SOUTH WINDS AND LOW LEVEL MOISTURE FEED SHOULD CONTINUE
THROUGH THURSDAY WITH THE ATMOSPHERE DESTABILIZING EACH AFTERNOON
AND EVENING. THERE ARE OPPORTUNITIES FOR NOCTURNAL MCS DEVELOPMENT
ALSO BUT THE MODELS DONT GIVE A CONSISTENT SIGNAL AS TO WHICH NIGHT
OR NIGHTS THIS WILL OCCUR. THE GEMREG FIRES A NOCTURNAL MCS ACROSS
THE NERN ZONES LATE TONIGHT WHILE THE NAM AND ECM FAVOR THE SAME
LOCATION LATE TUESDAY NIGHT. THE GFS DEVELOPS CONVECTION WEDNESDAY
NIGHT BUT THE NAM AND ECM ARE QUIET. OVERALL THE MODELS FAVOR WRN
AND NCNTL NEB FOR HIGHEST QPF VERSUS THE HIGH PLAINS TO THE WEST AND
THE MISSOURI VALLEY TO THE EAST.
DEEP UPPER LEVEL MOISTURE WILL CONTINUE TO FEED CLOCKWISE AROUND THE
UPPER LEVEL RIDGE ACROSS THE CNTL ROCKIES. THIS IN COMBINATION WITH
A BELT OF MODERATE WESTERLIES AROUND 50 KT AT 300MB ASSURES SUPPORT
FOR STORM DEVELOPMENT. GIVEN THAT THE 500MB FLOW WILL REMAIN WEAK AT
JUST 10 TO 20 KT...STORMS SHOULD CONTINUE TO EXHIBIT WEAK
ROTATION...TEND TO BE OUTFLOW DOMINANT AND COLD POOL DRIVEN. THUS
THE SEVERE WEATHER THREAT WILL BE RELATIVELY LOW UNLESS A SITUATION
DEVELOPS WHERE THE COLD POOL BECOMES VERY UNSTABLE AND DISCRETE
STORM DEVELOPMENT PRODUCES BOW SEGMENTS WHICH WOULD INCREASE THE RISK
OF WIND DAMAGE. THE BEST OPPORTUNITY FOR THIS MIGHT BE TODAY WITH
THE NAM FORECASTING 1500-2000 J/KG OF DOWNDRAFT CAPE. THE REST OF
THE MODEL RUN LOOKS QUIET IN TERMS OF WIND THREAT. MEAN STORM MOTION
IN THE NAM IS LESS THAN 10 KTS AND K INDICES OF 35 TO 40 IN ALL
MODELS WILL SUPPORT LOCALLY HEAVY RAINFALL.
THE MOISTURE WILL BE FEEDING NORTH THROUGH THE FCST AREA AROUND A
COOL CANADIAN HIGH PRESSURE SYSTEM CENTERED OVER THE MIDWEST. THIS
SHOULD LIMIT HIGHS TUESDAY AND WEDNESDAY TO THE UPPER 70S TO AROUND
80 AND LOWS IN THE UPPER 50S TO AROUND 60.
WEDNESDAY NIGHT THROUGH SUNDAY...
A SIGNIFICANT UPPER LEVEL TROF AND DEEP MOISTURE WILL PASS OVER THE
FCST AREA WEDNESDAY NIGHT AND PERHAPS THROUGH THURSDAY MORNING.
ADDITIONAL TSTM ACTIVITY IS EXPECTED WITH THIS WAVE. THEREAFTER THE
WRN U.S. RIDGE WILL AMPLIFY INTO THE NRN PLAINS. THE UPPER LEVEL
MOISTURE VANISHES AND A GRADUAL WARMING TREND DEVELOPS THROUGH
SUNDAY. BY SUNDAY H700 MB TEMPERATURES COULD RISE TO AROUND 14C AND
H10-5 THICKNESSES APPROACH 580DM. MEANWHILE K INDICES FALL OFF IN
THE ECM SOLN BUT REMAIN HIGH IN THE GFS...35-40C. THUS THE GFS
CONTINUES TO LACTATE WHILE THE ECM GOES DRY. CAP STRENGTH IS
RELATIVELY WEAK THROUGH SATURDAY...LESS THAN 12C SO ITS UNCLEAR IF
THE FCST AREA CAN REMAIN DRY THURSDAY AFTERNOON THROUGH SUNDAY WITH
FCST DEW POINTS IN THE 60S. SINCE THE FLOW ALOFT BECOMES ALMOST DUE
NORTH...SUBSIDENCE COULD MAINTAIN A DRY PATTERN.
TEMPERATURES RISE THROUGH THE 80S TO NEAR 90 BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1228 PM CDT MON AUG 12 2013
A TRICKY AVIATION FORECAST IS IN THE CARDS OVER THE NEXT 24 HOURS
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. WEAK MID LEVEL FLOW AND
THE LACK OF A FRONTAL BOUNDARY WILL MAKE IT DIFFICULT TO PINPOINT
TIMING AND LOCATION OF THUNDERSTORMS TONIGHT. BOTH THE NAM AND GFS
SOLNS HAD SOME SIGNIFICANT INITIALIZATION ISSUES THIS MORNING AND
RELIED HEAVILY ON THE SREF AND HIRES RUC SOLNS FOR THE 18Z TAF
FCSTS. THAT BEING SAID...THINKING HERE IS THAT MID AND UPPER LEVEL
CLOUDINESS WILL BE ON THE INCREASE LATER THIS AFTERNOON AND THIS
EVENING AS CONVECTION DIES OFF TO THE WEST OF THE FORECAST AREA.
COVERAGE OF ANY ISOLATED TSRAS THIS EVENING WILL BE TOO SPARSE TO
INCLUDE IN THE 18Z TAFS. HOWEVER...HIGHER CONFIDENCE IN
THUNDERSTORMS CREEPS INTO THE FORECAST ON TUESDAY MORNING AS THE
SREF...GFS AND NAM SOLNS BEGIN TO COME INTO BETTER AGREEMENT WITH
TSRA CHANCES ACROSS WESTERN NEBRASKA. WILL HANDLE THIS THREAT FOR
TSRAS WITH A PROB 30 GROUP AT BOTH TERMINALS FOR TUESDAY MORNING.
CIGS OVER THE NEXT 24 HOURS WILL GENERALLY RANGE FROM 6000 TO 15000
FT AGL. THE EXCEPTION WILL BE AT THE KVTN TERMINAL...AS SOME 1500 TO
2500 FT AGL CIGS ARE POSSIBLE AT THE KVTN TERMINAL THROUGH MID
AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CLB
SYNOPSIS...CDC
SHORT TERM...POWER
LONG TERM...CDC
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
140 AM CDT MON AUG 12 2013
.UPDATE...
ISSUED AT 119 AM CDT MON AUG 12 2013
UPDATED THE FORECAST OVERNIGHT TO INCREASE CHANCES OF PRECIPITATION
IN THE SOUTHERN CWA AS THE COLD FRONT SINKS SOUTH...AIDED BY
OUTFLOW...AND DECREASE CHANCES IN THE NORTH...ALTHOUGH I HAVE NOT
COMPLETELY REMOVED CHANCES...BECAUSE EVEN IN OUR NORTH WE SEEM TO
BE GETTING SOME SPURIOUS ELEVATED CONVECTION HERE AND THERE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 245 PM CDT SUN AUG 11 2013
A SURFACE TROUGH OF LOW PRESSURE ACROSS NORTHERN NEBRASKA THIS
AFTERNOON IS EXPECTED TO PROVIDE ENOUGH CONVERGENCE FOR THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE OUTLOOK
AREA BY LATE AFTERNOON AS THE CAP BEGINS TO WEAKEN. WHILE THE
INSTABILITY VALUES REMAIN HIGH...ON THE ORDER OF 3000 J/KG OF MU
CAPE...THE WIND SHEAR VALUES ARE VERY WEAK...AND PRIMARY CONCERN
WITH THESE STORMS WILL BE THE POTENTIAL FOR LARGE HAIL. MODELED
SOUNDINGS ALSO INDICATE AN INVERTED V ATMOSPHERIC PROFILE FOR THE
LATE AFTERNOON AND EARLY EVENING HOURS...SO STRONG WIND GUSTS MAY
ALSO BE A CONCERN. NOT SURPRISINGLY...THE ENTIRE OUTLOOK ARE
REMAINS IN A SLIGHT RISK FOR SEVERE WEATHER FROM SPC...WITH LARGE
HAIL AND WINDS BEING THE PRIMARY CONCERN.
SOME OF THE LATEST MODEL RUNS ARE INDICATING THE CONVECTION
CURRENTLY DEVELOPING ACROSS THE HIGH PLAINS AND ASSOCIATED WITH A
PASSING SHORTWAVE IN WV IMAGERY...WILL EVENTUALLY MERGE WITH
CONVECTION IN PROXIMITY OF THE SURFACE TROUGH...WHICH COULD RESULT
IN AN ACTIVE EVENING...PRECIPITATION WISE...ACROSS THE LOCAL
AREA. THE 12Z WRF APPEARS TO BE THE MOST AGGRESSIVE WITH THE
SCENARIO...AND THE 18Z RAP ALSO HINTING AT A SOLUTION SIMILAR TO
THIS...SO FELT CONFIDENT ENOUGH TO INCREASE POPS THROUGH THE EARLY
EVENING HOURS INTO THE 50 PERCENT RANGE ACROSS MOST OF THE AREA.
OTHERWISE...WITH THE SLOW MOVEMENT OF ANY STORMS THAT DO
DEVELOP...HEAVY RAINFALL WILL ALSO BE A CONCERN...AND CONTINUED
WITH THE POTENTIAL FOR VERY LOCALIZED FLOODING THIS EVENING AND
OVERNIGHT.
FOR MONDAY...EXPECT A MOSTLY DRY START TO THE DAY...WITH
INCREASING CHANCES FOR PRECIPITATION BY AFTERNOON AS WE COULD SEE
SOME CONVECTION REDEVELOP IN THE VICINITY OF THE STALLED OUT
FRONT/TROUGH WHICH WILL THEN BE ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 245 PM CDT SUN AUG 11 2013
COOLER THAN NORMAL SUMMER WEATHER WILL SETTLE IN ACROSS OUR REGION
FOR MUCH OF THE WORKWEEK IN A NORTHWEST FLOW REGIME ACROSS THE
CENTRAL PLAINS. WARMER AIR WILL RESIDE TO THE WEST FM THE DESERT SW
NORTH ACROSS THE ROCKIES...WHILE TO THE EAST...A TROUGH NEAR THE
HUDSON BAY WILL DEEPEN AND TRANSLATE ACROSS THE EASTERN CONUS.
COOLER AIR WILL BACK IN ACROSS THE PLAINS FM THE UPPER MIDWEST AND A
1022ISH MB SFC HIGH WILL BUILD SOUTH FM THIS AREA ONTO THE PLAINS...AND
WILL REINFORCE THE COOLER AIRMASS UNTIL AROUND THE THURSDAY TIME
FRAME. BY THE END OF THE WEEK AND HEADING INTO THE WEEKEND...THE
SFC RIDGE AXIS SLIDES EAST AND THE UPPER RIDGE OVER THE ROCKIES WILL
BEGINS TO BUILD TOWARDS THE PLAINS AND TEMPERATURES WILL BEGIN TO
MODERATE CLOSER TO SEASONAL NORMALS.
FOR CONVECTIVE POTENTIAL...CANNOT RULE OUT TSTM CHANCES DURING THIS
TIME FRAME...WITH DEVELOPMENT DEPENDENT UPON BOUNDARY LOCATIONS AND
TIMING OF WAVES. ON MONDAY...A FEW STORMS MAY LINGER IN THE
MORNING...WITH REDEVELOPMENT POSSIBLE DURING THE DAY ALONG A BACK
DOOR COOL FRONTAL BOUNDARY AND ALSO TO THE WEST IN AN UPSLOPE FLOW
REGIME. A STRONG TO SEVERE STORM IS POSSIBLE IN SUFFICIENT
INSTABILITY...BUT SHEAR REMAINS WEAK. THE BETTER PCPN CHCS BEGIN TO
FOCUS TO OUR WEST THROUGH MID WEEK...WITH SOME POTENTIAL FOR HIGH
PLAINS CONVECTION TO MIGRATE EAST TOWARDS OUR WESTERN CWA. AS
PATTERN CONTINUES TO AMPLIFY...FOCUS TURNS MORE TO TIMING OF WAVES
TOPPING RIDGE AND CROSSING THE PLAINS...WITH HIT OR MISS CHCS FOR
THE OUTER PERIODS...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE
POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 119 AM CDT MON AUG 12 2013
SHOWER AND THUNDERSTORM ACTIVITY SHOULD WANE AS THE COLD FRONT TO
THE SOUTH OF THE TERMINAL CONTINUES TO MOVE SOUTH. EVEN THOUGH
WIND DIRECTION WILL SHIFT TO THE NORTH...IT WILL REMAIN
LIGHT...AND WILL ALLOW SOME REDUCED VISIBILITY TO DEVELOP AS A
RESULT OF THE RECENT RAINFALL AND STILL ELEVATED DEWPOINTS.
CEILINGS SHOULD REMAIN IN THE MID-HIGH LEVELS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...SAR
LONG TERM...FAY
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
236 PM EDT MON AUG 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA LATER TONIGHT AND PASS THROUGH
THE REGION ON TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
FAIR AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY
MODERATING TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
18Z MON UPDATE... VFR CONDS SHOULD PERSIST AREA-WIDE THROUGH THE
EVE HRS...WITH A WEAKENING AREA OF CLDS/SHWRS LIKELY NOT PRODUCING
ANY RESTRICTIONS AS IT CROSSES SRN NY/NE PA FM ABT 21-03Z.
LTR TNT AND TUE...CONDS ARE EXPECTED TO DETERIORATE...AS A COLD
FRNT APPRCHS FROM THE NW...AND A SEPARATE WV MOVES THROUGH THE
DELMARVA RGN. IT IS ANTICIPATED THAT A BAND OF SHWRS...JUST AHD OF
THE COLD FRNT...WILL BEGIN TO IMPACT KSYR/KRME/KITH/KELM FROM
06-09Z...WITH A SEPARATE AREA OF SHWRS...ASSOCD WITH THE MORE SRN
SYSTEM...ALSO IMPACTING KAVP AT ABT THE SAME TIME. AT THIS
JUNCTURE...WE`LL GO WITH MVFR RESTRICTIONS. BRIEF IFR CONDS ARE
NOT OUT OF THE QUESTION IN HVYR SHWRS...BUT IT SEEMS LIKE THESE
EPISODES WILL BE BRIEF IN NATURE...AND HAVE THUS KEPT OUT OF THE
TERMINAL FCSTS ATTM.
ON TUE...SHWRS/EMBEDDED TSTMS SHOULD PROGRESS FROM NW-SE THROUGH
CNY/NE PA. AT KAVP...IT`S PROBABLE THAT TEMPORARY IMPROVEMENT WILL
TAKE PLACE AFTER 13-15Z...AS THE INITIAL AREA OF SHWRS MOVES
OUT...AND FRNTL SHWRS/TSTMS HOLD OFF TIL THE AFTN (AFTER 18Z).
ELSEWHERE (KSYR/KRME/KELM/KITH/BGM)...MVFR CONDS IN LWR
CIGS/SHWRS SHOULD PREVAIL. AT OUR NRN/WRN-MOST SITES
(KRME/KSYR/KELM)...FROPA MAY WELL TAKE PLACE FAST ENUF (BY ARND
16Z)...SO THAT DRIER AIR PUSHES IN AND IMPROVEMENT BACK TO VFR
OCCURS.
LGT/VRBL SFC WINDS INTO THIS EVE...WILL BECOME SRLY LATE TNT AT
5-10 KT. SW WINDS 5-10 KT ON TUE AM...SHOULD SHIFT INTO THE W AND NW
AFTER FROPA AT KSYR/KRME/KITH/KELM BY EARLY AFTN.
OUTLOOK...
TUE NGT...A PD OF MVFR CIGS PSBL...SPCLY ACRS CNY.
WED THRU SAT...MAINLY VFR. THE ONLY EXCEPTION WILL BE PSBL EARLY
AM VLY FOG AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...CMG/MLJ
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
233 PM EDT MON AUG 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA LATER TONIGHT AND PASS THROUGH
THE REGION IN TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
FAIR AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY
MODERATING TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
18Z MON UPDATE... VFR CONDS SHOULD PERSIST AREA-WIDE THROUGH THE
EVE HRS...WITH A WEAKENING AREA OF CLDS/SHWRS LIKELY NOT PRODUCING
ANY RESTRICTIONS AS IT CROSSES SRN NY/NE PA FM ABT 21-03Z.
LTR TNT AND TUE...CONDS ARE EXPECTED TO DETERIORATE...AS A COLD
FRNT APPRCHS FROM THE NW...AND A SEPARATE WV MOVES THROUGH THE
DELMARVA RGN. IT IS ANTICIPATED THAT A BAND OF SHWRS...JUST AHD OF
THE COLD FRNT...WILL BEGIN TO IMPACT KSYR/KRME/KITH/KELM FROM
06-09Z...WITH A SEPARATE AREA OF SHWRS...ASSOCD WITH THE MORE SRN
SYSTEM...ALSO IMPACTING KAVP AT ABT THE SAME TIME. AT THIS
JUNCTURE...WE`LL GO WITH MVFR RESTRICTIONS. BRIEF IFR CONDS ARE
NOT OUT OF THE QUESTION IN HVYR SHWRS...BUT IT SEEMS LIKE THESE
EPISODES WILL BE BRIEF IN NATURE...AND HAVE THUS KEPT OUT OF THE
TERMINAL FCSTS ATTM.
ON TUE...SHWRS/EMBEDDED TSTMS SHOULD PROGRESS FROM NW-SE THROUGH
CNY/NE PA. AT KAVP...IT`S PROBABLE THAT TEMPORARY IMPROVEMENT WILL
TAKE PLACE AFTER 13-15Z...AS THE INITIAL AREA OF SHWRS MOVES
OUT...AND FRNTL SHWRS/TSTMS HOLD OFF TIL THE AFTN (AFTER 18Z).
ELSEWHERE (KSYR/KRME/KELM/KITH/BGM)...MVFR CONDS IN LWR
CIGS/SHWRS SHOULD PREVAIL. AT OUR NRN/WRN-MOST SITES
(KRME/KSYR/KELM)...FROPA MAY WELL TAKE PLACE FAST ENUF (BY ARND
16Z)...SO THAT DRIER AIR PUSHES IN AND IMPROVEMENT BACK TO VFR
OCCURS.
LGT/VRBL SFC WINDS INTO THIS EVE...WILL BECOME SRLY LATE TNT AT
5-10 KT. SW WINDS 5-10 KT ON TUE AM...SHOULD SHIFT INTO THE W AND NW
AFTER FROPA AT KSYR/KRME/KITH/KELM BY EARLY AFTN.
OUTLOOK...
TUE NGT...A PD OF MVFR CIGS PSBL...SPCLY ACRS CNY.
WED THRU SAT...MAINLY VFR. THE ONLY EXCEPTION WILL BE PSBL EARLY
AM VLY FOG AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...CMG/MLJ
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
210 PM EDT MON AUG 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA LATER TONIGHT AND PASS THROUGH
THE REGION IN TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
FAIR AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY
MODERATING TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED ACROSS THE REGION TODAY WITH LIGHT W TO
SW WINDS BETWEEN 5-10 KTS. EXPECT SCT-BKN CU DEVELOPMENT LATER
THIS MORNING/EARLY AFTERNOON WITH BASES CENTERED BETWEEN 4 AND 6
KFT. ISOLATED SHWRS AND STORMS WILL BE POSSIBLE ACROSS THE REGION
TODAY HOWEVER COVERAGE WILL REMAIN FAIRLY ISOLATED THUS NO MENTION
IN MORNING FCST PACKAGE. SHWRS/ISOLATED STORMS TO BECOME MORE
WIDESPREAD AFTER 06Z AS A COLD FRONT APPROACHES. FOR NOW...EXPECT
SHWR ACTIVITY TO BEGIN WORKING INTO THE ELM/SYR/ITH SHORTLY AFTER
06Z...RME BY 08Z...AND BGM BY 09Z. FOR NOW...BEST COVERAGE LIKELY
HOLD OFF UNTIL ROUGHLY 10-12Z AT AVP. AS RAIN MOVES IN...EXPECT
PERIODIC MVFR CONDITIONS.
OUTLOOK...
TUE...MVFR IN SHRA/TSRA.
WED/THU/FRI...VFR...BRIEF IFR PSBL AT ELM IN EARLY MRNG VLY FOG.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
LONG TERM...CMG/MLJ
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
205 PM EDT MON AUG 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA LATER TONIGHT AND PASS THROUGH
THE REGION IN TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
FAIR AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY
MODERATING TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
$$
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED ACROSS THE REGION TODAY WITH LIGHT W TO
SW WINDS BETWEEN 5-10 KTS. EXPECT SCT-BKN CU DEVELOPMENT LATER
THIS MORNING/EARLY AFTERNOON WITH BASES CENTERED BETWEEN 4 AND 6
KFT. ISOLATED SHWRS AND STORMS WILL BE POSSIBLE ACROSS THE REGION
TODAY HOWEVER COVERAGE WILL REMAIN FAIRLY ISOLATED THUS NO MENTION
IN MORNING FCST PACKAGE. SHWRS/ISOLATED STORMS TO BECOME MORE
WIDESPREAD AFTER 06Z AS A COLD FRONT APPROACHES. FOR NOW...EXPECT
SHWR ACTIVITY TO BEGIN WORKING INTO THE ELM/SYR/ITH SHORTLY AFTER
06Z...RME BY 08Z...AND BGM BY 09Z. FOR NOW...BEST COVERAGE LIKELY
HOLD OFF UNTIL ROUGHLY 10-12Z AT AVP. AS RAIN MOVES IN...EXPECT
PERIODIC MVFR CONDITIONS.
OUTLOOK...
TUE...MVFR IN SHRA/TSRA.
WED/THU/FRI...VFR...BRIEF IFR PSBL AT ELM IN EARLY MRNG VLY FOG.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
LONG TERM...CMG/MLJ
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
728 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE SLOWLY ACROSS THE AREA LATE
TONIGHT INTO EARLY WEDNESDAY...STALLING OVER SOUTHERN SOUTH
CAROLINA WEDNESDAY THROUGH FRIDAY...BEFORE LIFTING BACK NORTH THIS
WEEKEND. THIS WILL RESULT IN SEVERAL PERIODS OF SIGNIFICANT RAINFALL
THROUGH THE UPCOMING WEEKEND. A DRYING TREND IS EXPECTED NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 730 PM TUESDAY...BASED ON THE LATEST FEW HRRR RUNS AND THE 12Z
SREF ENSEMBLES...I HAVE BUMPED POPS UP TO 60-70 PERCENT ACROSS SE
NORTH CAROLINA AND SOME OF THE ADJACENT SC BORDER COUNTIES TONIGHT.
WHILE THE BAND OF CONVECTION CURRENTLY ALONG THE SOUTHWARD-MOVING
FRONT IN NORTH CAROLINA MAY NOT MAKE IT HERE INTACT...MODELS ARE
QUITE INSISTENT NEW CONVECTION CURRENTLY DEVELOPING ACROSS CENTRAL
SOUTH CAROLINA WILL MAKE IT DOWN TO THE COAST LATE THIS EVENING AND
OVERNIGHT. ACROSS THE REMAINDER OF SOUTH CAROLINA SOUTH OF A LINE
FROM FLORENCE TO MARION AND CONWAY...A 50 POP (WHILE UNPALATABLE
FROM AN AESTHETIC SENSE) PROBABLY DESCRIBES THE PROBABILITY OF RAIN
THROUGH 6 AM PRETTY WELL. WITH THE EXPECTATION OF FAIRLY WIDESPREAD
CONVECTION I HAVE TRIMMED BACK FORECAST LOWS BY A COUPLE OF DEGREES
AS WELL...ESPECIALLY INLAND WHERE SOME COOLER AIR BEHIND THE FRONT
MAY HAVE THE BEST CHANCE OF FILTERING IN BEFORE DAYBREAK. PREVIOUS
DISCUSSION FROM 300 PM FOLLOWS...
ELONGATED SHORT-WAVE ENERGY WAS EVIDENT IN VAPOR ANIMATIONS THIS MID
AFTERNOON STRETCHING FROM KRDU TO KSOP TO KCAE. JUST OUT AHEAD OF
THIS FEATURE AM EXPECTING CONVECTION TO FILL IN THEN TRACK TO THE
ENE AT 20 MPH. DESPITE UNFAVORABLE LAPSE RATES ALOFT...PRECIPITABLE
WATERS REMAIN IN EXCESS OF 2 INCHES AND SURFACE BASED CAPES OF
2500-3500 J/KG WILL ALLOW FOR THE POTENTIAL FOR STRONG TSTMS TO
ERUPT. THERE MAY BE A LINEAR FASHION IN CONVECTION IN THE FORM OF
BROKEN LINE SEGMENTS...AND WITH FORWARD MODERATE SPEEDS WE COULD SEE
STRONG GUSTS OR EVEN ISOLATED WIND DAMAGE INTO THE EARLY TO MIDDLE
EVENING HOURS. WITH LOSS OF SURFACE HEATING SUSPECT WE MAY SEE A
LULL OF DECREASE IN CONVECTION INTO THE LATE EVENING. INTO EARLY
WEDNESDAY HOWEVER...AS THE APPROACHING SURFACE FRONT MERGES WITH AN
EXISTING PIEDMONT TROUGH...SURFACE CONVERGENCE WILL STRENGTHEN AND
WE COULD SEE A RESURGENCE OF SHOWERS AND STORMS AFTER 6Z. IT APPEARS
BY DAYBREAK WEDNESDAY THE FRONT WILL BE POSITIONED FROM NEAR OR
NORTH OF CAPE FEAR WESTWARD TO CENTRAL SOUTH CAROLINA. HAVE KEPT
MINIMUMS MILD IN THE UPPER 70S NEAR AND ALONG THE COAST TO THE
MIDDLE 70S OVER THE FAR INTERIOR...COOLEST NORTHERN TIER.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...A COLD FRONT WILL BE MOVING OR WILL HAVE MOVED
TROUGH MOST OF THE AREA BY THE BEGINNING OF THE PERIOD ON THE
STRENGTH OF A MID LEVEL TROUGH NOW SEEN IN WATER VAPOR ACROSS THE
UPPER MIDWEST. THE FRONT WILL SETTLE JUST SOUTH AND EAST OF THE
AREA. THE DILEMMA FOR THE SHORT TERM IS POPS AND QPF AMOUNTS.
LOOKING AT MODEL SOUNDINGS AND CONVECTIVE/STABLE PRECIPITATION FROM
THE GFS IT APPEARS MOST OF THE PRECIPITATION WILL BE STRATIFORM.
WITH MODEL GUIDANCE HIGH TEMPERATURES IN THE LOWER 80S AND DEWPOINTS
DROPPING WELL INTO THE 60S...THIS SEEMS REASONABLE. I HAVE CHANGED
MOST OF THE WEATHER TYPE TO SHOWERS WITH ONLY ISOLATED THUNDER AND
EVEN THIS MAY BE A STRETCH. QUITE FRANKLY THE ISENTROPIC LIFT ON THE
310K LAYER IS NOT THAT IMPRESSIVE WITH LOWER DEWPOINT AIR RIDING IN
FROM THE WEST OVER THE THERMAL PACKING NEAR THE FRONT. PERHAPS THIS
IS WHY THE GFS IS NOT THAT AGGRESSIVE WITH QPF AMOUNTS. WE ARE
SOMEWHAT LOWER ON QPF AMOUNTS THAN WPC GUIDANCE WITH 48 HOUR AMOUNTS
JUST UNDER AN INCH. AS FOR POPS I HAVE TRENDED VALUES USING THE SREF
PERCENTAGES OF 0.25 INCHES OR GREATER. THIS SHOWS HIGHER VALUES FROM
WEDNESDAY 1800 TO 0000 UTC AND AGAIN THURSDAY FROM 1200 TO 1800 UTC.
FINALLY I HAVE TRENDED DOWN ALL TEMPERATURES FOLLOWING THE NUMERICAL
GUIDANCE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...VERY PERSISTENT STALLED FRONT TO STILL BE THE
MAIN FACTOR IN PRODUCING WEATHER LOCALLY EARLY IN THE LONG TERM. THE
PRESENCE OF THE BOUNDARY TO YIELD HIGHER THAN CLIMO RAIN CHANCES AND
COOLER THAN CLIMO MAX TEMPS ON FRIDAY...THEN FRIDAY NIGHT INTO
SATURDAY MODEL AGREEMENT PRETTY GOOD THAT MOISTURE ASSOC WITH
TROPICAL WAVE IN CARIBBEAN MOVES INTO THE PICTURE. TOUGH TO SAY THE
SPEED WITH WHICH THE TROPICAL MOISTURE MOVES OUT SINCE ITS SO FAR
OUTSIDE OF THE UPPER AIR NETWORK BUT MODEL AGREEMENT SUGGESTS THIS
OCCURS SUNDAY ALBEIT FAIRLY GRADUALLY. MONDAY INTO TUESDAY BRINGS A
STRONG RETROGRESSION OF THE UPPER RIDGE INTO THE SOUTHEAST. THERE
WILL STILL BE ENOUGH LOW LEVEL MOISTURE AND PERHAPS EVEN VESTIGE OF
THE SURFACE BOUNDARY FOR RAIN CHANCES...JUST NOT AS HIGH AS EARLIER
IN THE PERIOD. MONDAY AND TUESDAY WILL ALSO FEATURE A RETURN OF
CLIMO TEMPS OR HIGHER.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...DIURNAL CONVECTION HAS DIMINISHED IN COVERAGE THIS
EVENING...THOUGH SOME STORMS CONTINUE FIRING OVER OUR INLAND AREAS.
THEREFORE...WILL INCLUDE VCTS FOR KFLO/KLBT IN THE NEAR TERM. HI-RES
GUIDANCE SHOWS MORE SHOWERS DEVELOPING OVERNIGHT...MAINLY NEAR THE
COAST...AS A COLD FRONT APPROACHES OUR CWA. HAVE ACCOUNTED FOR THIS
BY INTRODUCING VCSH FOR THE COASTAL TERMS AFTER MIDNIGHT. EXPECT VFR
TO PREVAIL...BUT BRIEF PERIODS OF MVFR OR LOWER ARE POSSIBLE IF A
STORM MOVES RIGHT OVER A TAF SITE. SOUTHWEST WINDS WILL VEER TO THE
NORTHWEST AND THEN NORTHEAST FOLLOWING FROPA...WHICH WILL BE AFTER
09Z INLAND/12Z COASTAL. MORE SHOWERS ARE EXPECTED ON WEDNESDAY AS
THE FRONT STALLS NEAR OUR AREA...WITH PERHAPS BETTER PCPN CHANCES AT
THE COASTAL TERMS DURING THE DAY.
EXTENDED OUTLOOK...SHOWERS LIKELY WITH ISOLATED T-STORMS POSSIBLE
THURSDAY THROUGH SUNDAY. HEAVY RAINFALL AT TIMES COULD PRODUCE
LOCALIZED PERIODS OF MVFR/IFR/LIFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 730 PM TUESDAY...WINDS ARE ABOUT AS STRONG AS THEY CAN GET
WITHOUT RAISING A SMALL CRAFT ADVISORY. OBSERVATIONS FROM THE FRYING
PAN SHOALS BUOY...SPRINGMAID PIER...AND THE OAK
ISLAND/SOUTHPORT/BALD HEAD ISLAND AREA SHOW AVERAGE SPEEDS AROUND 20
KNOTS WITH GUSTS AS HIGH AS 25 KNOTS WITHIN THE PAST HOUR. SEAS ARE
AS HIGH AS 5 FT AT THE WILMINGTON HARBOR BUOY JUST SOUTH OF
SOUTHPORT. MODELS SHOW A NEARLY STEADY STATE WIND PATTERN THROUGH
MIDNIGHT...WITH A VEERING AND SUBSIDING TREND IN WIND SPEEDS
EXPECTED LATE. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD
ACROSS THE NC WATERS LATER THIS EVENING AND OVERNIGHT...WITH
SCATTERED ACTIVITY EXPECTED TO MOVE ACROSS THE SC WATERS AFTER
MIDNIGHT. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
SEAS AND WINDS WILL RAMP UP A BIT AHEAD OF AN APPROACHING COLD
FRONT...AND A EXERCISE CAUTION STATEMENT WILL REMAIN IN PLACE...FOR
5 FOOT SEAS OFFSHORE AND GUSTS TO 20 KT. THE WIND-WAVE PORTION OF
THE WAVE SPECTRUM WILL CARRY MOST OF THE WAVE ENERGY MAKING FOR
STEEP SIDES 4-5 FOOT WAVES. ISOLATED TO SCATTERED TSTMS WILL BE
DIRECTED TOWARD THE ENE AND COULD IMPACT THE AREA WATERS WITH
LOCALLY HIGHER WINDS AND WAVES. MARINERS ARE ENCOURAGED TO OBTAIN A
RADAR FIX BEFORE HEADING OUT...EVEN ALONG THE INLAND AND
INTER-COASTAL WATERWAYS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...INITIALLY THERE WILL BE LIGHT WESTERLY WINDS
OVER THE COASTAL WATERS AS A FRONT WILL BE MAKING ITS WAY TO THE
SOUTH. BY MIDDAY WEDNESDAY A NORTHEAST FLOW WILL BE IN PLACE OVER
ALL THE WATERS AND WILL BE PICKING UP STEAM IN A RANGE OF 10-15
KNOTS. THIS WILL PREVAIL THROUGH THE REMAINDER OF THE PERIOD WITH A
SLIGHT VEERING OF DIRECTION TO THE EAST. WITH THE MODEST WIND
SPEEDS...WAVEWATCH IS ADVERTISING SIGNIFICANT SEAS OF 2-4 FEET AND
THESE SEEM REASONABLE.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...WITH A FRONT STALLED VERY NEAR THE AREA JUST
TO THE SOUTH A NORTHEASTERLY WIND SHOULD SLACKEN ON FRIDAY. WITH THE
LACK OF ANY APPRECIABLE SWELL ENERGY WAVES WILL BE RATHER DIMINUTIVE
AT 2 TO 3 FT. ON SATURDAY THE BOUNDARY MEANDERS A BIT CLOSER TO THE
REGION AND MAY BE CLOSE ENOUGH TO BEING STALLED ACROSS THE WATERS
THAT THE WIND DIRECTION FORECAST IS UNCERTAIN. WIND SPEEDS WILL BE
VERY LIGHT...UNDER 10KT. A FURTHER LITTLE JOG TO THE NORTH SATURDAY
NIGHT INTO SUNDAY WILL ALLOW FOR A SOUTHERLY DIRECTION TO BECOME
ESTABLISHED TO THE STILL VERY LIGHT WINDS. SEAS RELATIVELY UNCHANGED
THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MJC/TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1240 PM CDT MON AUG 12 2013
.UPDATE...
ISSUED AT 1240 PM CDT MON AUG 12 2013
SEEING THE CUMULUS AREA ACROSS NORTHWEST MN EXPANDING A LITTLE
FURTHER SOUTH NOW. WITH THE MORNING SUNSHINE ARE GETTING SOME
WEAK INSTABILITY FORMING THERE TOO. WILL KEEP THE ISOLATED SHOWER
MENTION ALTHOUGH WILL DELAY IT BY A FEW MORE HOURS. CONFIDENCE
REMAINS PRETTY LOW ON SEEING ANY SHOWER DEVELOPMENT AND IT WOULD
BE MINIMAL IF ANY DO FORM.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
CHALLENGE FOR THE FORECAST TODAY WILL BE SHOWERS IF ANY ALONG THE
BACK DOOR COLD FRONT SLIDING SOUTH OUT OF MANITOBA...CURRENTLY
NORTH OF WINNIPEG. CLOUDS ASSOCIATED WITH FRONT MAY CAUSE SOME
UNCERTAINTY WITH TEMPS HOWEVER CURRENT TIMING OF FROPA WILL STILL
GIVE MUCH OF THE AREA GOOD SOLAR THIS AFTERNOON. ALSO MOISTURE IS
LIMITED WITH MOSTLY A MID LEVEL BAND OF CLOUDS WHICH WILL BE FAIRLY
NARROW. WILL MAINTAIN HIGH TEMPS THIS AFTERNOON SIMILAR TO
YESTERDAYS MID TO UPPER 70S.
AS FOR POPS AND COVERAGE...IF ANYTHING ISOLATED SHOWERS AT BEST.
BEST FORCING REMAINS EAST CLOSER TO VORT LOBE AND SFC LOW PRESSURE
ACROSS THE NORTHERN GREAT LAKES. EC QPFS PAINT SOME VERY LIGHT
AMOUNTS ACROSS THE NORTHERN VALLEY AND UPPER DEVILS LAKE BASIN.
HAVE LEFT THIS AREA DRY AND KEPT THE SLIGHT POPS IN NW MN FOR THE
LATE MORNING AND INTO THE AFTERNOON. THIS AREA IS WHERE THE 00Z
GFS...06Z NAM AND THE 06Z HRRR HAVE SOME LIGHT QPF.
1025MB CANADIAN HIGH PRESSURE TO BUILD IN BEHIND FROPA THIS EVENING
AND CENTER OVER S MANITOBA BY TUESDAY MORNING. NORTHERLY WINDS LOWER
PWATS DOWN TO AROUND HALF AN INCH...CAUSING CLEAR SKIES AND COOL
TEMPS MONDAY NIGHT INTO TUESDAY MORNING. HAVE KEPT FOG MENTION
OUT OF THE FORECAST WITH NO RECENT PRECIP BUT WOULD NOT BE
SURPRISED TO SEE SOME SHALLOW GROUND FOG DEVELOP. WILL KEEP OUT OF
GRIDS FOR NOW. HIGH TEMPS TUESDAY VERY SIMILAR TO MONDAY A DEGREE
OR TOW COOLER AS THERMAL PROFILE MAY BE A TOUCH LOWER THAN MONDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
TUESDAY NIGHT THRU WEDNESDAY NIGHT...THE SFC HIGH PRESSURE SYSTEM
SLOWLY DRIFTS ACROSS THE FA AS 500MB CONFLUENT FLOW CONTINUES.
LITTLE TO NO CHANGE IN THERMAL PROFILE. HIGHS IN THE 70S WITH
LOWS IN THE UPPER 40S NORTH AND LOW 50S SOUTH.
THURSDAY THROUGH SUNDAY...LONG RANGE MODELS CONTINUE TO POINT TO
A SIGNIFICANT WARM UP FOR THE EXTENDED PERIOD. THERE APPEARS TO BE
HIGHER CONFIDENCE THAT THE RIDGE AXIS OVER THE ROCKIES WILL
TRANSLATE EASTWARD OVER THE NORTHERN PLAINS LATE THIS WEEK INTO
THE WEEKEND. THE WARMING TREND MAY PERSIST WELL INTO NEXT WEEK AND
BE THE MOST PROLONGED STRETCH OF ABOVE NORMAL TEMPERATURES FOR
THIS PART OF THE COUNTRY SO FAR THIS SUMMER. THE TIME PERIOD FOR
SIGNIFICANT AND WIDESPREAD PRECIPITATION NOW LOOKS LIKE IT MAY
HOLD OFF UNTIL NEXT SUNDAY. IT APPEARS THAT WE MAY EXPERIENCE SOME
MCS ACTIVITY DUE TO COMPLEXES RIDING OVER THE RIDGE AXIS WHICH
SHOULD BE IN PLACE OVER THE AREA. DUE TO THE INCREASINGLY DRY
CONDITIONS OVER THE REGION AS INDICATED BY THE LATEST DROUGHT
MONITOR...ANY SUBSTANTIAL RAINFALL WOULD BE A WELCOME RELIEF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1240 PM CDT MON AUG 12 2013
SOME CU POSSIBLE THIS AFTERNOON ALONG WITH NORTH WINDS AROUND 10
KNOTS. HIGH PRESSURE WILL LEAD TO MOSTLY CLEAR SKY AND LIGHT WINDS
TONIGHT INTO TUESDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GODON
SHORT TERM...JK
LONG TERM...BRAMER/JK
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
938 AM CDT MON AUG 12 2013
.UPDATE...
ISSUED AT 938 AM CDT MON AUG 12 2013
ONLY THING REALLY IN QUESTION FOR TODAY IS THE POSSIBILITY OF ANY
SHOWER DEVELOPMENT ACROSS OUR MN FA. NOT MUCH CLOUD COVER ACROSS
THE AREA NOW BUT THERE IS A BIT OF CUMULUS DEVELOPING ALONG THE
CANADIAN BORDER FROM THE LAKE OF THE WOODS INTO THE MN ARROWHEAD.
THERE IS SOME WEAK SHORT WAVE ENERGY DROPPING THRU OUR EAST TODAY
ALONG WITH SOME COOLER 500MB TEMPS. ALONG WITH THE MORNING SFC
HEATING THIS MAY BE ENOUGH TO SET OFF SOME AFTERNOON SHOWERS.
HOWEVER SOME OF THE NEW HIGH RES MODELS ARE LOOKING DRY. EITHER
WAY IT WOULD NOT BE A BIG DEAL AS FAR AS RAIN AMOUNTS. PREVIOUS
FORECAST HAD THE SHOWERS DEVELOPING BY MID MORNING AND WILL PUSH
THAT BACK TO THE AFTERNOON AND SEE WHAT HAPPENS. REST OF FORECAST
UNCHANGED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
CHALLENGE FOR THE FORECAST TODAY WILL BE SHOWERS IF ANY ALONG THE
BACK DOOR COLD FRONT SLIDING SOUTH OUT OF MANITOBA...CURRENTLY
NORTH OF WINNIPEG. CLOUDS ASSOCIATED WITH FRONT MAY CAUSE SOME
UNCERTAINTY WITH TEMPS HOWEVER CURRENT TIMING OF FROPA WILL STILL
GIVE MUCH OF THE AREA GOOD SOLAR THIS AFTERNOON. ALSO MOISTURE IS
LIMITED WITH MOSTLY A MID LEVEL BAND OF CLOUDS WHICH WILL BE FAIRLY
NARROW. WILL MAINTAIN HIGH TEMPS THIS AFTERNOON SIMILAR TO
YESTERDAYS MID TO UPPER 70S.
AS FOR POPS AND COVERAGE...IF ANYTHING ISOLATED SHOWERS AT BEST.
BEST FORCING REMAINS EAST CLOSER TO VORT LOBE AND SFC LOW PRESSURE
ACROSS THE NORTHERN GREAT LAKES. EC QPFS PAINT SOME VERY LIGHT
AMOUNTS ACROSS THE NORTHERN VALLEY AND UPPER DEVILS LAKE BASIN.
HAVE LEFT THIS AREA DRY AND KEPT THE SLIGHT POPS IN NW MN FOR THE
LATE MORNING AND INTO THE AFTERNOON. THIS AREA IS WHERE THE 00Z
GFS...06Z NAM AND THE 06Z HRRR HAVE SOME LIGHT QPF.
1025MB CANADIAN HIGH PRESSURE TO BUILD IN BEHIND FROPA THIS EVENING
AND CENTER OVER S MANITOBA BY TUESDAY MORNING. NORTHERLY WINDS LOWER
PWATS DOWN TO AROUND HALF AN INCH...CAUSING CLEAR SKIES AND COOL
TEMPS MONDAY NIGHT INTO TUESDAY MORNING. HAVE KEPT FOG MENTION
OUT OF THE FORECAST WITH NO RECENT PRECIP BUT WOULD NOT BE
SURPRISED TO SEE SOME SHALLOW GROUND FOG DEVELOP. WILL KEEP OUT OF
GRIDS FOR NOW. HIGH TEMPS TUESDAY VERY SIMILAR TO MONDAY A DEGREE
OR TOW COOLER AS THERMAL PROFILE MAY BE A TOUCH LOWER THAN MONDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
TUESDAY NIGHT THRU WEDNESDAY NIGHT...THE SFC HIGH PRESSURE SYSTEM
SLOWLY DRIFTS ACROSS THE FA AS 500MB CONFLUENT FLOW CONTINUES.
LITTLE TO NO CHANGE IN THERMAL PROFILE. HIGHS IN THE 70S WITH
LOWS IN THE UPPER 40S NORTH AND LOW 50S SOUTH.
THURSDAY THROUGH SUNDAY...LONG RANGE MODELS CONTINUE TO POINT TO
A SIGNIFICANT WARM UP FOR THE EXTENDED PERIOD. THERE APPEARS TO BE
HIGHER CONFIDENCE THAT THE RIDGE AXIS OVER THE ROCKIES WILL
TRANSLATE EASTWARD OVER THE NORTHERN PLAINS LATE THIS WEEK INTO
THE WEEKEND. THE WARMING TREND MAY PERSIST WELL INTO NEXT WEEK AND
BE THE MOST PROLONGED STRETCH OF ABOVE NORMAL TEMPERATURES FOR
THIS PART OF THE COUNTRY SO FAR THIS SUMMER. THE TIME PERIOD FOR
SIGNIFICANT AND WIDESPREAD PRECIPITATION NOW LOOKS LIKE IT MAY
HOLD OFF UNTIL NEXT SUNDAY. IT APPEARS THAT WE MAY EXPERIENCE SOME
MCS ACTIVITY DUE TO COMPLEXES RIDING OVER THE RIDGE AXIS WHICH
SHOULD BE IN PLACE OVER THE AREA. DUE TO THE INCREASINGLY DRY
CONDITIONS OVER THE REGION AS INDICATED BY THE LATEST DROUGHT
MONITOR...ANY SUBSTANTIAL RAINFALL WOULD BE A WELCOME RELIEF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 648 AM CDT MON AUG 12 2013
VFR TODAY WITH NORTH WINDS 5 TO 15 KTS. MAYBE A ISO SHOWER IN NW
MN...HAVE LEFT OUT OF TAFS FOR NOW AS CHANCES APPEARS TO BE VERY
REMOTE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GODON
SHORT TERM...JK
LONG TERM...BRAMER/JK
AVIATION...JK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
648 AM CDT MON AUG 12 2013
.UPDATE...
ISSUED AT 648 AM CDT MON AUG 12 2013
REMOVED ANY FOG MENTION FOR THE MORNING WITH THIS UPDATE. NO OTHER
CHANGES AS FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
CHALLENGE FOR THE FORECAST TODAY WILL BE SHOWERS IF ANY ALONG THE
BACK DOOR COLD FRONT SLIDING SOUTH OUT OF MANITOBA...CURRENTLY
NORTH OF WINNIPEG. CLOUDS ASSOCIATED WITH FRONT MAY CAUSE SOME
UNCERTAINTY WITH TEMPS HOWEVER CURRENT TIMING OF FROPA WILL STILL
GIVE MUCH OF THE AREA GOOD SOLAR THIS AFTERNOON. ALSO MOISTURE IS
LIMITED WITH MOSTLY A MID LEVEL BAND OF CLOUDS WHICH WILL BE FAIRLY
NARROW. WILL MAINTAIN HIGH TEMPS THIS AFTERNOON SIMILAR TO
YESTERDAYS MID TO UPPER 70S.
AS FOR POPS AND COVERAGE...IF ANYTHING ISOLATED SHOWERS AT BEST.
BEST FORCING REMAINS EAST CLOSER TO VORT LOBE AND SFC LOW PRESSURE
ACROSS THE NORTHERN GREAT LAKES. EC QPFS PAINT SOME VERY LIGHT
AMOUNTS ACROSS THE NORTHERN VALLEY AND UPPER DEVILS LAKE BASIN.
HAVE LEFT THIS AREA DRY AND KEPT THE SLIGHT POPS IN NW MN FOR THE
LATE MORNING AND INTO THE AFTERNOON. THIS AREA IS WHERE THE 00Z
GFS...06Z NAM AND THE 06Z HRRR HAVE SOME LIGHT QPF.
1025MB CANADIAN HIGH PRESSURE TO BUILD IN BEHIND FROPA THIS EVENING
AND CENTER OVER S MANITOBA BY TUESDAY MORNING. NORTHERLY WINDS LOWER
PWATS DOWN TO AROUND HALF AN INCH...CAUSING CLEAR SKIES AND COOL
TEMPS MONDAY NIGHT INTO TUESDAY MORNING. HAVE KEPT FOG MENTION
OUT OF THE FORECAST WITH NO RECENT PRECIP BUT WOULD NOT BE
SURPRISED TO SEE SOME SHALLOW GROUND FOG DEVELOP. WILL KEEP OUT OF
GRIDS FOR NOW. HIGH TEMPS TUESDAY VERY SIMILAR TO MONDAY A DEGREE
OR TOW COOLER AS THERMAL PROFILE MAY BE A TOUCH LOWER THAN MONDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
TUESDAY NIGHT THRU WEDNESDAY NIGHT...THE SFC HIGH PRESSURE SYSTEM
SLOWLY DRIFTS ACROSS THE FA AS 500MB CONFLUENT FLOW CONTINUES.
LITTLE TO NO CHANGE IN THERMAL PROFILE. HIGHS IN THE 70S WITH
LOWS IN THE UPPER 40S NORTH AND LOW 50S SOUTH.
THURSDAY THROUGH SUNDAY...LONG RANGE MODELS CONTINUE TO POINT TO
A SIGNIFICANT WARM UP FOR THE EXTENDED PERIOD. THERE APPEARS TO BE
HIGHER CONFIDENCE THAT THE RIDGE AXIS OVER THE ROCKIES WILL
TRANSLATE EASTWARD OVER THE NORTHERN PLAINS LATE THIS WEEK INTO
THE WEEKEND. THE WARMING TREND MAY PERSIST WELL INTO NEXT WEEK AND
BE THE MOST PROLONGED STRETCH OF ABOVE NORMAL TEMPERATURES FOR
THIS PART OF THE COUNTRY SO FAR THIS SUMMER. THE TIME PERIOD FOR
SIGNIFICANT AND WIDESPREAD PRECIPITATION NOW LOOKS LIKE IT MAY
HOLD OFF UNTIL NEXT SUNDAY. IT APPEARS THAT WE MAY EXPERIENCE SOME
MCS ACTIVITY DUE TO COMPLEXES RIDING OVER THE RIDGE AXIS WHICH
SHOULD BE IN PLACE OVER THE AREA. DUE TO THE INCREASINGLY DRY
CONDITIONS OVER THE REGION AS INDICATED BY THE LATEST DROUGHT
MONITOR...ANY SUBSTANTIAL RAINFALL WOULD BE A WELCOME RELIEF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 648 AM CDT MON AUG 12 2013
VFR TODAY WITH NORTH WINDS 5 TO 15 KTS. MAYBE A ISO SHOWER IN NW
MN... HAVE LEFT OUT OF TAFS FOR NOW AS CHANCES APPEARS TO BE VERY
REMOTE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JK
SHORT TERM...JK
LONG TERM...BRAMER/JK
AVIATION...JK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
350 AM CDT MON AUG 12 2013
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
CHALLENGE FOR THE FORECAST TODAY WILL BE SHOWERS IF ANY ALONG THE
BACK DOOR COLD FRONT SLIDING SOUTH OUT OF MANITOBA...CURRENTLY
NORTH OF WINNIPEG. CLOUDS ASSOCIATED WITH FRONT MAY CAUSE SOME
UNCERTAINTY WITH TEMPS HOWEVER CURRENT TIMING OF FROPA WILL STILL
GIVE MUCH OF THE AREA GOOD SOLAR THIS AFTERNOON. ALSO MOISTURE IS
LIMITED WITH MOSTLY A MID LEVEL BAND OF CLOUDS WHICH WILL BE FAIRLY
NARROW. WILL MAINTAIN HIGH TEMPS THIS AFTERNOON SIMILAR TO
YESTERDAYS MID TO UPPER 70S.
AS FOR POPS AND COVERAGE...IF ANYTHING ISOLATED SHOWERS AT BEST.
BEST FORCING REMAINS EAST CLOSER TO VORT LOBE AND SFC LOW PRESSURE
ACROSS THE NORTHERN GREAT LAKES. EC QPFS PAINT SOME VERY LIGHT
AMOUNTS ACROSS THE NORTHERN VALLEY AND UPPER DEVILS LAKE BASIN.
HAVE LEFT THIS AREA DRY AND KEPT THE SLIGHT POPS IN NW MN FOR THE
LATE MORNING AND INTO THE AFTERNOON. THIS AREA IS WHERE THE 00Z
GFS...06Z NAM AND THE 06Z HRRR HAVE SOME LIGHT QPF.
1025MB CANADIAN HIGH PRESSURE TO BUILD IN BEHIND FROPA THIS EVENING
AND CENTER OVER S MANITOBA BY TUESDAY MORNING. NORTHERLY WINDS LOWER
PWATS DOWN TO AROUND HALF AN INCH...CAUSING CLEAR SKIES AND COOL
TEMPS MONDAY NIGHT INTO TUESDAY MORNING. HAVE KEPT FOG MENTION
OUT OF THE FORECAST WITH NO RECENT PRECIP BUT WOULD NOT BE
SURPRISED TO SEE SOME SHALLOW GROUND FOG DEVELOP. WILL KEEP OUT OF
GRIDS FOR NOW. HIGH TEMPS TUESDAY VERY SIMILAR TO MONDAY A DEGREE
OR TOW COOLER AS THERMAL PROFILE MAY BE A TOUCH LOWER THAN MONDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON AUG 12 2013
TUESDAY NIGHT THRU WEDNESDAY NIGHT...THE SFC HIGH PRESSURE SYSTEM
SLOWLY DRIFTS ACROSS THE FA AS 500MB CONFLUENT FLOW CONTINUES.
LITTLE TO NO CHANGE IN THERMAL PROFILE. HIGHS IN THE 70S WITH
LOWS IN THE UPPER 40S NORTH AND LOW 50S SOUTH.
THURSDAY THROUGH SUNDAY...LONG RANGE MODELS CONTINUE TO POINT TO
A SIGNIFICANT WARM UP FOR THE EXTENDED PERIOD. THERE APPEARS TO BE
HIGHER CONFIDENCE THAT THE RIDGE AXIS OVER THE ROCKIES WILL
TRANSLATE EASTWARD OVER THE NORTHERN PLAINS LATE THIS WEEK INTO
THE WEEKEND. THE WARMING TREND MAY PERSIST WELL INTO NEXT WEEK AND
BE THE MOST PROLONGED STRETCH OF ABOVE NORMAL TEMPERATURES FOR
THIS PART OF THE COUNTRY SO FAR THIS SUMMER. THE TIME PERIOD FOR
SIGNIFICANT AND WIDESPREAD PRECIPITATION NOW LOOKS LIKE IT MAY
HOLD OFF UNTIL NEXT SUNDAY. IT APPEARS THAT WE MAY EXPERIENCE SOME
MCS ACTIVITY DUE TO COMPLEXES RIDING OVER THE RIDGE AXIS WHICH
SHOULD BE IN PLACE OVER THE AREA. DUE TO THE INCREASINGLY DRY
CONDITIONS OVER THE REGION AS INDICATED BY THE LATEST DROUGHT
MONITOR...ANY SUBSTANTIAL RAINFALL WOULD BE A WELCOME RELIEF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1121 PM CDT SUN AUG 11 2013
WILL SEE SOME VFR CIGS SWING THROUGH NE FA...BJI...TAF SITE DURING
THE MORNING AS AN UPPER LEVEL DISTURBANCE SWINGS THROUGH S
MB/ONTARIO. OTHERWISE NO CIGS EXPECTED. IN SPITE OF SKC AND LIGHT
WINDS STILL NOT ENOUGH CONFIDENCE ON FOG POTENTIAL TO INCLUDE IN
TAFS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...JK
LONG TERM...BRAMER/JK
AVIATION...VOELKER
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
946 PM CDT TUE AUG 13 2013
.UPDATE...
REDUCED RAIN CHANCES ACROSS MUCH OF THE AREA FOR THE REST OF
TONIGHT. ADDED PATCHY FOG MENTION ACROSS THE NORTHWEST HALF OF
OKLAHOMA LATER TONIGHT INTO WEDNESDAY MORNING.
&&
.DISCUSSION...
RAIN CHANCES HAVE DIMINISHED FOR NOW. THEY MAY INCREASE AFTER 3
AM NEAR AND SOUTH OF THE RED RIVER.
BAND OF SHOWERS FROM WEATHERFORD TO STILLWATER CONTINUES TO
DIMINISH. GENERALLY...EXPECT THIS TREND TO CONTINUE. KEPT 20
TO 40 PERCENT RAIN CHANCES IN THESE AREAS.
LATEST HRRR/RAP13 SUGGESTS THAT A FEW MORE SHOWERS AND STORMS MAY
DEVELOP NEAR AND SOUTH OF THE RED RIVER AFTER 3 PM TONIGHT WHERE
DEEPER MOISTURE AND INSTABILITY EXIST. KEPT 20 TO 30 PERCENT
CHANCES IN THESE AREAS. NO SEVERE STORMS ARE EXPECTED...THOUGH
LOCALLY HEAVY DOWNPOURS MAY BE POSSIBLE.
FOG MAY BE A CONCERN LATE TONIGHT INTO WEDNESDAY MORNING WITH
MOIST UPSLOPE FLOW PARTICULARLY OVER NORTHWEST OKLAHOMA. ADDED
PATCHY FOG MENTION DUE TO MODERATE CONFIDENCE OF OCCURRENCE.
WIDESPREAD DENSE FOG REMAINS UNLIKELY.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 629 PM CDT TUE AUG 13 2013/
AVIATION...
0Z TAFS... SHOWERS/STORMS WILL AFFECT KPNC THIS EVENING. THIS
ACTIVITY MAY MAKE IT AS FAR SOUTH AS KOKC/KOUN BUT CHANCES TOO LOW
FOR MENTION ATTM. SHOWERS/STORMS WILL BE POSSIBLE AGAIN WED AFTN
ACROSS PARTS OF SOUTHERN/WESTERN OK AND NORTH TEXAS BUT CHANCES
ALSO TOO LOW AT SOME SITES FOR MENTION IN TAF. SOME IFR CEILINGS
COULD DEVELOP OVERNIGHT IN SOME LOCATIONS, OTHERWISE VFR/MVFR
CONDITIONS EXPECTED.
PREV DISCUSSION... /ISSUED 603 PM CDT TUE AUG 13 2013/
UPDATE...
INCREASED RAIN CHANCES THROUGH 10 PM THIS EVENING ACROSS FAR
NORTHERN OKLAHOMA...AND DECREASED THEM ELSEWHERE.
DISCUSSION...
SHOWERS AND A FEW THUNDERSTORMS WITH LOCALLY HEAVY
RAINFALL OF 1 TO 2 INCHES MAY OCCUR THIS EVENING ACROSS
FAR NORTHERN OKLAHOMA...NORTH OF A FREEDOM TO FAIRVIEW TO
STILLWATER LINE. THIS COMPLEX CONTINUES TO SLOWLY DRIFT
SOUTH...BUT SHOULD WEAKEN OVER NEXT FEW HOURS DUE TO THE
LOSS OF DAYTIME HEATING. THESE STORMS SHOULD STAY BELOW
SEVERE LIMITS DUE TO WEAK INSTABILITY. LATEST MODELS HAVE BEEN
MISHANDLING THIS COMPLEX...EXCEPT FOR THE HRRR WHICH SUGGESTS
THESE STORMS WILL QUICKLY DIMINISH AROUND SUNSET.
STORMS HAVE DIMINISHED ACROSS WESTERN NORTH TEXAS. THERE IS
CHANCE THAT A FEW ADDITIONAL STORMS DEVELOP OR MOVE INTO THESE
AREAS FROM THE WEST OVER THE NEXT SEVERAL HOURS.
ACROSS THE REST OF THE AREA...KEPT A 20 PERCENT CHANCE FOR
STORMS TONIGHT. WITHOUT A STRONG FOCUS TO PROVIDE LIFT...BELIEVE
MOST PLACES WILL REMAIN DRY. MAY UPDATE LATER THIS EVENING
TO ADJUST RAIN CHANCES DOWNWARD.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 344 PM CDT TUE AUG 13 2013/
DISCUSSION...
MAIN AREA OF CONVECTION OVER CENTRAL/SOUTH CENTRAL
KANSAS WILL CONTINUE TO DRIFT SOUTH AND SOUTHEAST
THIS AFTERNOON AND EARLY EVENING. STORMS SHOULD
GRADUALLY DECREASE IN COVERAGE AND INTENSITY
BY THE EARLY EVENING.
OTHER STORMS HAVE FORMED ACROSS NORTH TEXAS AND THE SOUTHERN
TEXAS PANHANDLE WHERE TEMPERATURES HAVE WARMED INTO THE LOWER AND
MID 90S. A FEW STRONG STORMS WILL BE POSSIBLE THROUGH THE LATE
AFTERNOON/EARLY EVENING WITH STRONG WINDS AND HEAVY RAINFALL
THE MAIN HAZARDS.
THE CENTER OF HIGH PRESSURE AND DRIER AIR WILL BUILD FROM THE
NORTHERN PLAINS INTO THE UPPER MIDWEST/MID MISSISSIPPI VALLEY
TONIGHT INTO WEDNESDAY. THIS WILL FILTER DRIER AIR INTO NORTHERN
AND EASTERN PARTS OF THE FA...AND DECREASE RAIN CHANCES IN THE
SHORT TERM.
A COUPLE OF WAVES WILL MOVE THROUGH A NORTH TO NORTHWEST
FLOW THURSDAY INTO EARLY FRIDAY. THIS WILL BRING AN
INCREASE IN SHOWER AND STORM CHANCES DURING THIS
PERIOD...ESPECIALLY ACROSS THE NORTHERN HALF OF
OKLAHOMA.
MAINLY DRY CONDITIONS ARE EXPECTED OVER THE WEEKEND AS
AN UPPER RIDGE BUILDS SLOWLY EAST. BY EARLY NEXT WEEK...
THE GFS IN MORE AGGRESSIVE IN WEAKENING THE RIDGE AS
ANOTHER TROUGH MOVES ACROSS THE NORTHERN AND CENTRAL
ROCKIES. THIS WOULD PROVIDE ANOTHER OPPORTUNITY FOR
SHOWERS AND STORMS. THE EC HOLDS MORE RIDGING ALOFT
ACROSS THE SOUTHERN PLAINS. FOR NOW WILL MAINTAIN
A DRY FORECAST WITH VERY WARM/HOT TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 70 83 67 84 / 20 20 10 20
HOBART OK 69 86 69 86 / 20 30 20 20
WICHITA FALLS TX 73 89 72 89 / 20 40 20 30
GAGE OK 64 82 66 85 / 10 20 30 30
PONCA CITY OK 64 82 64 83 / 20 10 10 20
DURANT OK 72 87 67 88 / 10 40 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
629 PM CDT TUE AUG 13 2013
.AVIATION...
0Z TAFS... SHOWERS/STORMS WILL AFFECT KPNC THIS EVENING. THIS
ACTIVITY MAY MAKE IT AS FAR SOUTH AS KOKC/KOUN BUT CHANCES TOO LOW
FOR MENTION ATTM. SHOWERS/STORMS WILL BE POSSIBLE AGAIN WED AFTN
ACROSS PARTS OF SOUTHERN/WESTERN OK AND NORTH TEXAS BUT CHANCES
ALSO TOO LOW AT SOME SITES FOR MENTION IN TAF. SOME IFR CEILINGS
COULD DEVELOP OVERNIGHT IN SOME LOCATIONS, OTHERWISE VFR/MVFR
CONDITIONS EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 603 PM CDT TUE AUG 13 2013/
UPDATE...
INCREASED RAIN CHANCES THROUGH 10 PM THIS EVENING ACROSS FAR
NORTHERN OKLAHOMA...AND DECREASED THEM ELSEWHERE.
DISCUSSION...
SHOWERS AND A FEW THUNDERSTORMS WITH LOCALLY HEAVY
RAINFALL OF 1 TO 2 INCHES MAY OCCUR THIS EVENING ACROSS
FAR NORTHERN OKLAHOMA...NORTH OF A FREEDOM TO FAIRVIEW TO
STILLWATER LINE. THIS COMPLEX CONTINUES TO SLOWLY DRIFT
SOUTH...BUT SHOULD WEAKEN OVER NEXT FEW HOURS DUE TO THE
LOSS OF DAYTIME HEATING. THESE STORMS SHOULD STAY BELOW
SEVERE LIMITS DUE TO WEAK INSTABILITY. LATEST MODELS HAVE BEEN
MISHANDLING THIS COMPLEX...EXCEPT FOR THE HRRR WHICH SUGGESTS
THESE STORMS WILL QUICKLY DIMINISH AROUND SUNSET.
STORMS HAVE DIMINISHED ACROSS WESTERN NORTH TEXAS. THERE IS
CHANCE THAT A FEW ADDITIONAL STORMS DEVELOP OR MOVE INTO THESE
AREAS FROM THE WEST OVER THE NEXT SEVERAL HOURS.
ACROSS THE REST OF THE AREA...KEPT A 20 PERCENT CHANCE FOR
STORMS TONIGHT. WITHOUT A STRONG FOCUS TO PROVIDE LIFT...BELIEVE
MOST PLACES WILL REMAIN DRY. MAY UPDATE LATER THIS EVENING
TO ADJUST RAIN CHANCES DOWNWARD.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 344 PM CDT TUE AUG 13 2013/
DISCUSSION...
MAIN AREA OF CONVECTION OVER CENTRAL/SOUTH CENTRAL
KANSAS WILL CONTINUE TO DRIFT SOUTH AND SOUTHEAST
THIS AFTERNOON AND EARLY EVENING. STORMS SHOULD
GRADUALLY DECREASE IN COVERAGE AND INTENSITY
BY THE EARLY EVENING.
OTHER STORMS HAVE FORMED ACROSS NORTH TEXAS AND THE SOUTHERN
TEXAS PANHANDLE WHERE TEMPERATURES HAVE WARMED INTO THE LOWER AND
MID 90S. A FEW STRONG STORMS WILL BE POSSIBLE THROUGH THE LATE
AFTERNOON/EARLY EVENING WITH STRONG WINDS AND HEAVY RAINFALL
THE MAIN HAZARDS.
THE CENTER OF HIGH PRESSURE AND DRIER AIR WILL BUILD FROM THE
NORTHERN PLAINS INTO THE UPPER MIDWEST/MID MISSISSIPPI VALLEY
TONIGHT INTO WEDNESDAY. THIS WILL FILTER DRIER AIR INTO NORTHERN
AND EASTERN PARTS OF THE FA...AND DECREASE RAIN CHANCES IN THE
SHORT TERM.
A COUPLE OF WAVES WILL MOVE THROUGH A NORTH TO NORTHWEST
FLOW THURSDAY INTO EARLY FRIDAY. THIS WILL BRING AN
INCREASE IN SHOWER AND STORM CHANCES DURING THIS
PERIOD...ESPECIALLY ACROSS THE NORTHERN HALF OF
OKLAHOMA.
MAINLY DRY CONDITIONS ARE EXPECTED OVER THE WEEKEND AS
AN UPPER RIDGE BUILDS SLOWLY EAST. BY EARLY NEXT WEEK...
THE GFS IN MORE AGGRESSIVE IN WEAKENING THE RIDGE AS
ANOTHER TROUGH MOVES ACROSS THE NORTHERN AND CENTRAL
ROCKIES. THIS WOULD PROVIDE ANOTHER OPPORTUNITY FOR
SHOWERS AND STORMS. THE EC HOLDS MORE RIDGING ALOFT
ACROSS THE SOUTHERN PLAINS. FOR NOW WILL MAINTAIN
A DRY FORECAST WITH VERY WARM/HOT TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 68 83 67 84 / 20 20 10 20
HOBART OK 68 86 69 86 / 20 30 20 20
WICHITA FALLS TX 72 89 72 89 / 20 40 20 30
GAGE OK 64 82 66 85 / 20 20 30 30
PONCA CITY OK 64 82 64 83 / 50 10 10 20
DURANT OK 71 87 67 88 / 20 40 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25/25
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
603 PM CDT TUE AUG 13 2013
.UPDATE...
INCREASED RAIN CHANCES THROUGH 10 PM THIS EVENING ACROSS FAR
NORTHERN OKLAHOMA...AND DECREASED THEM ELSEWHERE.
&&
.DISCUSSION...
SHOWERS AND A FEW THUNDERSTORMS WITH LOCALLY HEAVY
RAINFALL OF 1 TO 2 INCHES MAY OCCUR THIS EVENING ACROSS
FAR NORTHERN OKLAHOMA...NORTH OF A FREEDOM TO FAIRVIEW TO
STILLWATER LINE. THIS COMPLEX CONTINUES TO SLOWLY DRIFT
SOUTH...BUT SHOULD WEAKEN OVER NEXT FEW HOURS DUE TO THE
LOSS OF DAYTIME HEATING. THESE STORMS SHOULD STAY BELOW
SEVERE LIMITS DUE TO WEAK INSTABILITY. LATEST MODELS HAVE BEEN
MISHANDLING THIS COMPLEX...EXCEPT FOR THE HRRR WHICH SUGGESTS
THESE STORMS WILL QUICKLY DIMINISH AROUND SUNSET.
STORMS HAVE DIMINISHED ACROSS WESTERN NORTH TEXAS. THERE IS
CHANCE THAT A FEW ADDITIONAL STORMS DEVELOP OR MOVE INTO THESE
AREAS FROM THE WEST OVER THE NEXT SEVERAL HOURS.
ACROSS THE REST OF THE AREA...KEPT A 20 PERCENT CHANCE FOR
STORMS TONIGHT. WITHOUT A STRONG FOCUS TO PROVIDE LIFT...BELIEVE
MOST PLACES WILL REMAIN DRY. MAY UPDATE LATER THIS EVENING
TO ADJUST RAIN CHANCES DOWNWARD.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 344 PM CDT TUE AUG 13 2013/
DISCUSSION...
MAIN AREA OF CONVECTION OVER CENTRAL/SOUTH CENTRAL
KANSAS WILL CONTINUE TO DRIFT SOUTH AND SOUTHEAST
THIS AFTERNOON AND EARLY EVENING. STORMS SHOULD
GRADUALLY DECREASE IN COVERAGE AND INTENSITY
BY THE EARLY EVENING.
OTHER STORMS HAVE FORMED ACROSS NORTH TEXAS AND THE SOUTHERN
TEXAS PANHANDLE WHERE TEMPERATURES HAVE WARMED INTO THE LOWER AND
MID 90S. A FEW STRONG STORMS WILL BE POSSIBLE THROUGH THE LATE
AFTERNOON/EARLY EVENING WITH STRONG WINDS AND HEAVY RAINFALL
THE MAIN HAZARDS.
THE CENTER OF HIGH PRESSURE AND DRIER AIR WILL BUILD FROM THE
NORTHERN PLAINS INTO THE UPPER MIDWEST/MID MISSISSIPPI VALLEY
TONIGHT INTO WEDNESDAY. THIS WILL FILTER DRIER AIR INTO NORTHERN
AND EASTERN PARTS OF THE FA...AND DECREASE RAIN CHANCES IN THE
SHORT TERM.
A COUPLE OF WAVES WILL MOVE THROUGH A NORTH TO NORTHWEST
FLOW THURSDAY INTO EARLY FRIDAY. THIS WILL BRING AN
INCREASE IN SHOWER AND STORM CHANCES DURING THIS
PERIOD...ESPECIALLY ACROSS THE NORTHERN HALF OF
OKLAHOMA.
MAINLY DRY CONDITIONS ARE EXPECTED OVER THE WEEKEND AS
AN UPPER RIDGE BUILDS SLOWLY EAST. BY EARLY NEXT WEEK...
THE GFS IN MORE AGGRESSIVE IN WEAKENING THE RIDGE AS
ANOTHER TROUGH MOVES ACROSS THE NORTHERN AND CENTRAL
ROCKIES. THIS WOULD PROVIDE ANOTHER OPPORTUNITY FOR
SHOWERS AND STORMS. THE EC HOLDS MORE RIDGING ALOFT
ACROSS THE SOUTHERN PLAINS. FOR NOW WILL MAINTAIN
A DRY FORECAST WITH VERY WARM/HOT TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 68 83 67 84 / 20 20 10 20
HOBART OK 68 86 69 86 / 20 30 20 20
WICHITA FALLS TX 72 89 72 89 / 20 40 20 30
GAGE OK 64 82 66 85 / 20 20 30 30
PONCA CITY OK 64 82 64 83 / 50 10 10 20
DURANT OK 71 87 67 88 / 20 40 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25
AREA FORECAST DISCUSSION
NWS TULSA OK
621 AM CDT MON AUG 12 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
ONGOING CONVECTION CURRENTLY SPREADING INTO NE OK WILL CONTINUE
EASTWARD WITH PERIODIC FLIGHT IMPACTS FOR NE OK AND EVENTUALLY FAR
NW SITES. EVOLUTION OF CONVECTION THROUGH THE REMAINDER OF THE
AFTERNOON AND THROUGH TONIGHT IS UNCERTAIN...HOWEVER EXPECTATIONS
ARE THAT THE BULK OF THE HEAVIEST PRECIP WILL BE ALONG AND NORTH
OF A SLOW MOVING FRONTAL BOUNDARY WHICH WILL BE NEARER NORTHER
LOCATIONS THROUGH TONIGHT. FORECAST WILL CALL FOR LONG PERIODS OF
VCTS AND/OR PREVAILING TSRA AND ALLOW FOR LATER FORECASTS TO
HIGHLIGHT PERIODS OF HIGHER CONFIDENCE FLIGHT IMPACTS.
&&
.PREV DISCUSSION... /ISSUED 311 AM CDT MON AUG 12 2013/
DISCUSSION...
THE MAIN CONCERN WITH THE FORECAST THIS MORNING IS THE POTENTIAL FOR
A PROLONGED PERIOD OF INTERMITTENT HEAVY RAINFALL OVER THE NEXT
COUPLE OF DAYS... WITH THE POSSIBILITY OF RENEWED FLOODING ISSUES
ACROSS MUCH OF THE AREA.
CONVECTIVE ACTIVITY CURRENTLY ONGOING ACROSS WESTERN AND CENTRAL
OKLAHOMA IS FORECAST TO SPREAD EASTWARD ACROSS THE FORECAST AREA
DURING THE DAY TODAY. BOTH THE LOCAL WRF AND THE HRRR DEPICT THIS AS
REMAINING MOSTLY SCATTERED IN NATURE. HOWEVER... ANY HEAVIER STORMS
OR TRAINING OF CELLS COULD QUICKLY LEAD TO LOCALIZED FLOODING...
GIVEN THE AMOUNTS OF RAINFALL THE AREA HAS RECEIVED OF LATE. THERE
WILL ALSO BE THE POTENTIAL FOR STORMS TO BECOME STRONG TO SEVERE
DURING THE DAY TODAY GIVEN THE AMOUNT OF INSTABILITY AND SHEAR PRESENT.
THE MAIN THREAT FOR WIDESPREAD HEAVY RAINFALL WILL BEGIN OVERNIGHT
TONIGHT. SEVERAL ROUNDS OF HEAVY THUNDERSTORMS WILL LIKELY AFFECT
THE REGION THROUGH TUESDAY UNTIL A COLD FRONT SWEEPS SOUTHWARD
THROUGH THE REGION BRINGING DRIER AIR INTO THE AREA. A FLASH FLOOD
WATCH WILL BECOME EFFECTIVE THIS MORNING THROUGH 0Z TUESDAY.
DEPENDING ON THE EVOLUTION OF THE EVENT AND PROGRESS OF THE FRONT...
THIS WATCH MAY EVENTUALLY NEED TO BE EXTENDED IN TIME INTO TUESDAY
EVENING.
SCATTERED PRECIPITATION MAY LAST THROUGH THE DAY WEDNESDAY. HOWEVER...
AFTER THAT... DRY AND MILD CONDITIONS WILL PREVAIL INTO AND THROUGH
THE UPCOMING WEEKEND. SOME OF THE COOLEST OVERNIGHT LOWS OF THE
SEASON WILL OCCUR THURSDAY THROUGH SATURDAY MORNINGS. READINGS IN
NORTHWEST ARKANSAS ARE EXPECTED TO DIP INTO THE 50S... WITH LOW TO
MID 60S ACROSS MUCH OF THE REST OF THE FORECAST AREA. DAYTIME HIGH
TEMPERATURES WILL CONTINUE TO RUN BELOW SEASONAL AVERAGES... AND
WITH DEWPOINTS IN THE UPPER 50S TO LOWER 60S SHOULD FEEL QUITE
UNSEASONABLY PLEASANT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 89 72 84 70 / 60 40 60 50
FSM 91 73 86 71 / 60 60 70 70
MLC 95 73 89 71 / 20 50 70 70
BVO 88 70 83 68 / 80 40 50 50
FYV 85 68 83 67 / 80 70 60 50
BYV 83 68 83 65 / 80 70 50 40
MKO 90 72 84 70 / 70 40 70 60
MIO 86 69 85 66 / 80 30 40 40
F10 92 73 85 70 / 30 40 70 70
HHW 95 75 94 73 / 10 30 30 50
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH UNTIL 7 PM TUESDAY FOR OKZ054-OKZ055-OKZ056-
OKZ057-OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-OKZ063-OKZ064-
OKZ065-OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-OKZ071-OKZ072-
OKZ073-OKZ074-OKZ075-OKZ076.
AR...FLASH FLOOD WATCH UNTIL 7 PM TUESDAY FOR ARZ001-ARZ002-ARZ010-
ARZ011-ARZ019-ARZ020-ARZ029.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
311 AM CDT MON AUG 12 2013
.DISCUSSION...
THE MAIN CONCERN WITH THE FORECAST THIS MORNING IS THE POTENTIAL FOR
A PROLONGED PERIOD OF INTERMITTENT HEAVY RAINFALL OVER THE NEXT
COUPLE OF DAYS... WITH THE POSSIBILITY OF RENEWED FLOODING ISSUES
ACROSS MUCH OF THE AREA.
CONVECTIVE ACTIVITY CURRENTLY ONGOING ACROSS WESTERN AND CENTRAL
OKLAHOMA IS FORECAST TO SPREAD EASTWARD ACROSS THE FORECAST AREA
DURING THE DAY TODAY. BOTH THE LOCAL WRF AND THE HRRR DEPICT THIS AS
REMAINING MOSTLY SCATTERED IN NATURE. HOWEVER... ANY HEAVIER STORMS
OR TRAINING OF CELLS COULD QUICKLY LEAD TO LOCALIZED FLOODING...
GIVEN THE AMOUNTS OF RAINFALL THE AREA HAS RECEIVED OF LATE. THERE
WILL ALSO BE THE POTENTIAL FOR STORMS TO BECOME STRONG TO SEVERE
DURING THE DAY TODAY GIVEN THE AMOUNT OF INSTABILITY AND SHEAR PRESENT.
THE MAIN THREAT FOR WIDESPREAD HEAVY RAINFALL WILL BEGIN OVERNIGHT
TONIGHT. SEVERAL ROUNDS OF HEAVY THUNDERSTORMS WILL LIKELY AFFECT
THE REGION THROUGH TUESDAY UNTIL A COLD FRONT SWEEPS SOUTHWARD
THROUGH THE REGION BRINGING DRIER AIR INTO THE AREA. A FLASH FLOOD
WATCH WILL BECOME EFFECTIVE THIS MORNING THROUGH 0Z TUESDAY.
DEPENDING ON THE EVOLUTION OF THE EVENT AND PROGRESS OF THE FRONT...
THIS WATCH MAY EVENTUALLY NEED TO BE EXTENDED IN TIME INTO TUESDAY
EVENING.
SCATTERED PRECIPITATION MAY LAST THROUGH THE DAY WEDNESDAY. HOWEVER...
AFTER THAT... DRY AND MILD CONDITIONS WILL PREVAIL INTO AND THROUGH
THE UPCOMING WEEKEND. SOME OF THE COOLEST OVERNIGHT LOWS OF THE
SEASON WILL OCCUR THURSDAY THROUGH SATURDAY MORNINGS. READINGS IN
NORTHWEST ARKANSAS ARE EXPECTED TO DIP INTO THE 50S... WITH LOW TO
MID 60S ACROSS MUCH OF THE REST OF THE FORECAST AREA. DAYTIME HIGH
TEMPERATURES WILL CONTINUE TO RUN BELOW SEASONAL AVERAGES... AND
WITH DEWPOINTS IN THE UPPER 50S TO LOWER 60S SHOULD FEEL QUITE
UNSEASONABLY PLEASANT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 89 72 84 70 / 60 40 60 50
FSM 91 73 86 71 / 60 60 70 70
MLC 95 73 89 71 / 20 50 70 70
BVO 88 70 83 68 / 80 40 50 50
FYV 85 68 83 67 / 80 70 60 50
BYV 83 68 83 65 / 80 70 50 40
MKO 90 72 84 70 / 70 40 70 60
MIO 86 69 85 66 / 80 30 40 40
F10 92 73 85 70 / 30 40 70 70
HHW 95 75 94 73 / 10 30 30 50
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM 7 AM MONDAY TO 7 PM TUESDAY FOR OKZ054-
OKZ055-OKZ056-OKZ057-OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-
OKZ063-OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-
OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076.
AR...FLASH FLOOD WATCH FROM 7 AM MONDAY TO 7 PM TUESDAY FOR ARZ001-
ARZ002-ARZ010-ARZ011-ARZ019-ARZ020-ARZ029.
&&
$$
SHORT TERM...07
LONG TERM....06
AREA FORECAST DISCUSSION
NWS NORMAN OK
1210 AM CDT MON AUG 12 2013
.AVIATION...
SHOWERS/TSTMS CONTINUE TO ADVANCE NEWD THROUGH WRN OK. WILL INCLUDE PREVAILING
OR TEMPO TSRA IN MOST SITES EARLY IN THE PD. EXPECT ACTIVITY TO
GRDLY DIMINISH LATER THIS MORNING. MORE STORMS LIKELY TO REDEVELOP
LATER THIS AFTERNOON AND TONIGHT...ESP ACROSS NRN OK. OUTSIDE THE
THUNDERSTORMS...GENERALLY VFR CONDITIONS WILL PREVAIL.
&&
.PREV DISCUSSION... /ISSUED 915 PM CDT SUN AUG 11 2013/
.DISCUSSION...
A COUPLE OF CLUSTERS OF THUNDERSTORMS OVER SOUTHWEST OKLAHOMA AND
WESTERN NORTH TEXAS ARE LIKELY TO PERSIST THROUGH THE LATE
EVENING. SHORT-RANGE MODELS SUGGEST THAT CONVECTION WILL SHIFT
INTO NORTHWEST OKLAHOMA AFTER MIDNIGHT...AND PERHAPS FORM INTO AN
MCS ACROSS NORTHERN OKLAHOMA AND SOUTHERN KANSAS. THIS SCENARIO IS
STILL FAIRLY UNCERTAIN...SO THE EXISTING OVERNIGHT
POPS...QPF...ETC. STILL LOOK REASONABLE. THE FORECAST WAS UPDATED
EARLIER TO ACCOUNT FOR THE CONVECTIVE CLUSTERS...AND ADDITIONAL
UPDATES MAY BE NEEDED FOR SHORT-TERM TRENDS THIS
EVENING/OVERNIGHT.
OTHERWISE...NO CHANGES ARE CURRENTLY PLANNED FOR THE FORECAST.
&&
.PREV DISCUSSION... /ISSUED 641 PM CDT SUN AUG 11 2013/
AVIATION...
12/00Z TAFS...VFR CONDITIONS EXPECTED TO PREVAIL ACROSS THE REGION
OUTSIDE OF ANTICIPATED TSRA. FAIRLY WIDE VARIETY OF MODEL
SOLUTIONS ON EVOLUTION OF STORMS THIS EVENING THROUGH TOMORROW.
TAFS WILL BE BASED PRIMARILY ON HRRR AND WRF...WHICH YIELD
POTENTIAL FOR TSRA TO LINGER ACROSS SW OKLAHOMA THIS EVENING AND
COMPLEX OF STORMS TO APPROACH NORTHERN OKLAHOMA TOWARD 09Z FROM
KANSAS. THIS COMPLEX PROGD TO WEAKEN AND REDEVELOPMENT ACROSS
CENTRAL PORTIONS OF OKLAHOMA TOMORROW AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 73 92 72 90 / 20 30 40 40
HOBART OK 73 95 72 93 / 70 30 20 40
WICHITA FALLS TX 74 99 74 96 / 40 10 10 20
GAGE OK 69 93 68 87 / 50 40 40 50
PONCA CITY OK 71 90 69 86 / 40 40 60 50
DURANT OK 75 96 73 94 / 10 10 20 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
23/11
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
333 PM EDT MON AUG 12 2013
.SYNOPSIS...
PARTLY SUNNY...WARM...AND INCREASINGLY HUMID AIR WILL COVER MUCH OF
THE REGION LATE THIS AFTERNOON AND TONIGHT. SHOWERS WILL MOVE ACROSS
THE NORTHERN MOUNTAINS LATE THIS AFTERNOON WITH ADDITIONAL SHOWERS
AND SCATTERED THUNDERSTORMS DEVELOPING ACROSS THE WESTERN HALF OF
THE STATE OVERNIGHT AHEAD OF AN APPROACHING STRONG COLD FRONT. THE
FRONT WILL PUSH THROUGH THE STATE ON TUESDAY. IN THE WAKE OF THE
COLD FRONT A LARGE AREA OF CANADIAN HIGH PRESSURE WILL BUILD
SOUTHEAST INTO THE STATE. THIS HIGH WILL BRING SEVERAL PLEASANT BUT
RELATIVELY COOL DAYS AND NIGHTS. THE ASSOCIATED DEEP TROUGH AND COOL
AIR ALOFT WILL MODIFY AND WEAKEN FRIDAY AND INTO THE COMING WEEKEND.
TEMPERATURES SHOULD TREND BACK TOWARD NORMAL FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
WEAK RIDGING RESULTED IN A DECENT AMOUNT OF SUNSHINE WITH LIGHT WIND
ACROSS MOST OF THE FCST AREA THIS AFTERNOON. WEAK NEGATIVE...OR
NEUTRAL LLVL THETA-E ADVECTION ACCOMPANYING THIS HIGH ALONG WITH
STABLE MID LEVELS CAPPED ANY DEPTH TO THE SCT-BKN CU OR STRATO CU
CLOUDS SO FAR.
THE EXCEPTION WAS ACROSS THE NORTHWEST MOUNTAINS WHERE A THICK
LAYERED CLOUD SHIELD AND SHOWERS SPREAD QUICKLY EAST INTO THE KBFD
BY 18Z. THERE IS A HIGH LIKELIHOOD OF SHOWERS ACRS OUR NW ZONES
DURING THE MID AFTERNOON THROUGH EARLY EVENING...TAPERING TO
SCATTERED SHOWERS ACROSS THE MTNS TO THE NE OF KIPT. RAINFALL
AMOUNTS OF 0.1 - 0.2 WERE PAINTED IN ACROSS OUR NRN MTN ZONES WITH
THE HIGHEST AMOUNTS INVOF KBFD AND PTS WEST.
TEMPERATURES LATE THIS AFTERNOON ACROSS MOST OF CENTRAL PENN AND THE
SUSQ REGION WILL BE CLOSE TO NORMAL HIGHS FOR MID AUGUST...EXCEPT
FOR SLIGHTLY BELOW NORMAL TEMPS ACROSS THE NW MTNS WHERE MORE
EXTENSIVE CLOUD COVER AND NUMEROUS SHOWERS WILL OVERSPREAD THE
REGION THIS AFTERNOON.
FOR TONIGHT...THE LATEST HRRR AND 12/15Z OPERATIONAL AND ENSEMBLE
RUNS INDICATE INCREASING COVERAGE OF SHOWERS AND EMBEDDED TSRA
/MAINLY AFTER MIDNIGHT/ AS THE THERMALLY DIRECT CELL /OF A JET MAX
JUST TO OUR NORTH/ AND ASSOCIATED SWRLY LLJ ENHANCES UVVEL. LOWEST
POPS FOR SHOWERS WILL BE ACROSS THE MIDDLE AND LOWER SUSQ
VALLEY...AND CONFINED MAINLY TO THE 06-12Z TIMEFRAME.
RAINFALL AMOUNTS WILL VARY FROM AROUND 0.50 INCH NEAR KBFD...TO LESS
THAN 0.10 NEAR AND TO THE SE OF KMDT.
LOW TEMPS WILL BE ON THE MILD SIDE AHEAD OF THE CFRONT...AND IN THE
U50S TO LOWER 60S ACROSS THE MTNS...WITH MID TO UPPER 60S ACROSS THE
CENTRAL AND SE VALLEYS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION DURING THE MORNING
TO EARLY AFTERNOON HOURS. TIMING OF THE FRONT AND DEPARTING UPPER
LEVEL FORCING TO OUR NORTHEAST SHOULD LIMIT THE THREAT FOR
SIGNIFICANT/DEEP CONVECTION IN MOST PLACES...EXCEPT FOR PERHAPS ONE
OR TWO STRONG TSRA ACROSS OUR FAR EAST AFTER 16Z RIGHT NEAR THE
CFRONT.
PLENTY OF LOW CLOUDS SHOULD FORM THEN LINGER IN THE COOLER/MOIST
UPSLOPE FLOW IN THE WAKE OF THE FRONT ACROSS THE ALLEGHENY PLATEAU
/KJST TO KBFD/...KEEPING TEMPS IN THE U60S TO LOWER 70S.
BKN...LAYERED CU AND ALTO CU WILL OCCUR ELSEWHERE WITH SCATTERED TO
NUMEROUS SHOWERS FOR SEVERAL HOURS ALONG AND IN ADVANCE OF THE
FRONT. HIGHS WILL BE BETWEEN 75-80F THROUGHOUT THE CENTRAL AND
SOUTHERN VALLEYS.
ADDITIONAL RAINFALL AMOUNTS TUESDAY WILL LIKELY AVERAGE UNDER 0.25
INCH IN MOST PLACES...BUT LOCATIONS SEEING A TSRA ACROSS THE SUSQ
VALLEY MAY SEE LOCALLY OVER 0.50 GIVEN THE NW EDGE OF 1.5-1.75 INCH
PWATS SLIDING ACROSS THE AREA AHEAD OF THE FRONT DURING THE
MORNING/MIDDAY HOURS.
TUESDAY AFTERNOON WILL FEATURE A DRYING TREND WITH A 10-20 MPH WEST
TO NW BREEZE AS A WELL-DEFINED DRY SLOT MOVES OVER THE REGION WITH
PWATS STEADILY DECREASING /TO BELOW 0.75 INCH ACROSS THE NW MTNS/
THROUGH THE AFTERNOON AND EVENING HOURS.
THE SOUTHERN...TAIL END OF A MID LEVEL THERMAL TROUGH WITH STEEP
850-500 MB LAPSE RATES WILL BRING A SEVERAL HOUR PERIOD OF CLOUDS
AND A LOW CHC FOR SHOWERS ACROSS THE NRN TIER COUNTIES LATER TUESDAY
NIGHT. RAINFALL AMOUNTS WILL BE LIGHT.
OTHERWISE...LOOK FOR GENERALLY PARTLY CLOUDY CONDITIONS WITH A
NORTHWEST BREEZE GRADUALLY DIMINISHING TO UNDER 7 KTS AFTER MIDNIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
OVERVIEW...THE LATEST ARRAY OF GUIDANCE SHOWS THE LARGE SCALE MEAN
FLOW OVER THE CONUS TRENDING/TRANSITIONING TOWARD A MORE TYPICAL
MID-AUGUST PATTERN WITH THE UPPER-LEVEL WESTERLIES SHIFTING NWD TO
LATITUDES ALONG AND NORTH OF THE US-CANADIAN BORDER BY EARLY NEXT
WEEK. THE PRONOUNCED/DEEP UPPER TROUGH GRIPPING THE NORTHEAST AND
MID-ATLANTIC STATES EARLY IN THE PERIOD SHOULD WEAKEN WITH
TIME...AS THE REMAINING NEGATIVE HEIGHT ANOMALY DRIFTS SWWD INTO
THE LWR MS RVR VLY PER THE 12Z GEFS MEAN. AT THE SFC...A LARGE
DOME OF HIGH PRESSURE /WITH ORIGINS OVER CENTRAL CANADA/ WILL
SPREAD SEWD FROM THE UPPER PLAINS ACROSS THE GRT LKS/OH VLY AND
TAKE UP RESIDENCE IN THE NEW ENGLAND AREA OVER THE WEEKEND. A WAVY
SFC FRONT OVER THE SE STATES IS PROGGED TO LIFT BACK NWD TOWARD
THE CAROLINA COAST/SRN MID-ATLC REGION BY SAT-MON.
HIGHLIGHTS...DRY WX SHOULD PREVAIL THROUGH THE MAJORITY OF THE
MEDIUM RANGE COURTESY OF HIGH PRES MIGRATING SLOWLY EWD FROM THE
UPPER MIDWEST TO THE NEW ENGLAND STATES. PWATS STAY BELOW NORMAL
THROUGH FRIDAY...RESULTING IN COMFORTABLE HUMIDITY AND COOL
NIGHTTIME TEMPS WITH LOWS IN THE 40S/50S. SOME UPPER 30S REMAIN
POSSIBLE OVER THE NRN TIER. CLEAR/CALM/COOL NIGHTS SHOULD ALSO
LEAD TO PREDAWN AND EARLY MORNING FOG IN THE VALLEYS. DAYTIME
HIGHS WILL AVERAGE NEAR TO BELOW NORMAL. A GRADUALLY MOISTENING
EAST-SOUTHEAST LOW LEVEL FLOW FAVORS AN INCREASE IN SKY COVER AND
LOW CHC FOR SHOWERS LATE IN THE WEEKEND AND INTO EARLY NEXT WEEK.
THE 12Z GFS AND 00Z ECMWF HANDLE THE EAST COAST FRONTAL BOUNDARY
REASONABLY WELL...WITH A CONSENSUS MULTI-MODEL/MOS/HPC SUPERBLEND
SUPPORTING THE HIGHEST POPS AROUND 19 AUGUST.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
EXPECT MAINLY VFR CONDITIONS TO PERSIST THROUGH THE REST OF TODAY
AND THROUGH THIS EVENING AT ALL TAF SITES WITH THE LONE EXCEPTION OF
KBFD...WHERE MVFR VSBYS AND PERHAPS PERIODS OF MVFR CIGS WILL
ACCOMPANY A LARGE AREA OF SHOWERS THAT HAVE RECENTLY SPREAD INTO THE
REGION FROM LAKE ERIE AND PTS WEST.
OUTSIDE OF THE NW MTNS...CONVECTION WILL BE ISOLATED AND BRIEF AS
WEAK RIDGING AT THE SFC AND ALOFT MOVES OVERHEAD.
WARM ADVECTION AND INCREASING DEEP LAYER MOISTURE AHEAD OF A STRONG
COLD FRONT WILL BRING DETERIORATING CIGS AND VSBYS LATE THIS EVENING
INTO THE MORNING HOURS TUESDAY. MVFR WITH POCKETS OF IFR WILL
ACCOMPANY SCTD TO NUMEROUS SHOWERS AND ISOLATED TSRA.
CIGS NEAR AND IN THE WAKE OF THE COLD FRONT WILL LIKELY DROP INTO
THE LIFR RANGE FOR AT LEAST A FEW HOURS TUESDAY MORNING /FROM 10Z ON
IN KBFD AND KJST/ AS THE COOL MOIST AIR IS LIFTED OVER THE WRN PENN
MTNS.
THE STRONG COLD FRONT WILL MOVE ACROSS THE REGION DURING THE MORNING
AND EARLY AFTERNOON HOURS TUESDAY. EXPECT BANDS OF SHOWERS AND
THUNDERSTORMS TO FORM. DYNAMICS LAG THE FRONT SOME...BUT STILL SOME
CONCERN FOR BRIEF...STRONG WIND GUSTS WITH ANY STORMS...ESP ACROSS
THE SUSQ RIVER VALLEY.
NORTHWEST BREEZE OF 10-15 KTS SUSTAINED FOLLOWS THE CFRONT TUESDAY
AFTERNOON AND EVENING BEFORE SUBSIDING A BIT TUESDAY NIGHT.
WINDY ON WED...AS DEEPER/COLDER AIR WORKS SOUTHWARD.
LOOKING AT DRY CONDITIONS AFT WED.
OUTLOOK...
WED-SAT...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
308 PM EDT MON AUG 12 2013
.SYNOPSIS...
PARTLY SUNNY...WARM...AND INCREASINGLY HUMID AIR WILL COVER MUCH OF
THE REGION LATE THIS AFTERNOON AND TONIGHT. SHOWERS WILL MOVE ACROSS
THE NORTHERN MOUNTAINS LATE THIS AFTERNOON WITH ADDITIONAL SHOWERS
AND SCATTERED THUNDERSTORMS DEVELOPING ACROSS THE WESTERN HALF OF
THE STATE OVERNIGHT AHEAD OF AN APPROACHING STRONG COLD FRONT. THE
FRONT WILL PUSH THROUGH THE STATE ON TUESDAY. IN THE WAKE OF THE
COLD FRONT A LARGE AREA OF CANADIAN HIGH PRESSURE WILL BUILD
SOUTHEAST INTO THE STATE. THIS HIGH WILL BRING SEVERAL PLEASANT BUT
RELATIVELY COOL DAYS AND NIGHTS. THE ASSOCIATED DEEP TROUGH AND COOL
AIR ALOFT WILL MODIFY AND WEAKEN FRIDAY AND INTO THE COMING WEEKEND.
TEMPERATURES SHOULD TREND BACK TOWARD NORMAL FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK RIDGING RESULTED IN A DECENT AMOUNT OF SUNSHINE WITH LIGHT WIND
ACROSS MOST OF THE FCST AREA THIS AFTERNOON. WEAK NEGATIVE...OR
NEUTRAL LLVL THETA-E ADVECTION ACCOMPANYING THIS HIGH ALONG WITH
STABLE MID LEVELS CAPPED ANY DEPTH TO THE SCT-BKN CU OR STRATO CU
CLOUDS SO FAR.
THE EXCEPTION WAS ACROSS THE NORTHWEST MOUNTAINS WHERE A THICK
LAYERED CLOUD SHIELD AND SHOWERS SPREAD QUICKLY EAST INTO THE KBFD
BY 18Z. THERE IS A HIGH LIKELIHOOD OF SHOWERS ACRS OUR NW ZONES
DURING THE MID AFTERNOON THROUGH EARLY EVENING...TAPERING TO
SCATTERED SHOWERS ACROSS THE MTNS TO THE NE OF KIPT. RAINFALL
AMOUNTS OF 0.1 - 0.2 WERE PAINTED IN ACROSS OUR NRN MTN ZONES WITH
THE HIGHEST AMOUNTS INVOF KBFD AND PTS WEST.
TEMPERATURES LATE THIS AFTERNOON ACROSS MOST OF CENTRAL PENN AND THE
SUSQ REGION WILL BE CLOSE TO NORMAL HIGHS FOR MID AUGUST...EXCEPT
FOR SLIGHTLY BELOW NORMAL TEMPS ACROSS THE NW MTNS WHERE MORE
EXTENSIVE CLOUD COVER AND NUMEROUS SHOWERS WILL OVERSPREAD THE
REGION THIS AFTERNOON.
FOR TONIGHT...THE LATEST HRRR AND 12/15Z OPERATIONAL AND ENSEMBLE
RUNS INDICATE INCREASING COVERAGE OF SHOWERS AND EMBEDDED TSRA
/MAINLY AFTER MIDNIGHT/ AS THE THERMALLY DIRECT CELL /OF A JET MAX
JUST TO OUR NORTH/ AND ASSOCIATED SWRLY LLJ ENHANCES UVVEL. LOWEST
POPS FOR SHOWERS WILL BE ACROSS THE MIDDLE AND LOWER SUSQ
VALLEY...AND CONFINED MAINLY TO THE 06-12Z TIMEFRAME.
RAINFALL AMOUNTS WILL VARY FROM AROUND 0.50 INCH NEAR KBFD...TO LESS
THAN 0.10 NEAR AND TO THE SE OF KMDT.
LOW TEMPS WILL BE ON THE MILD SIDE AHEAD OF THE CFRONT...AND IN THE
U50S TO LOWER 60S ACROSS THE MTNS...WITH MID TO UPPER 60S ACROSS THE
CENTRAL AND SE VALLEYS.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION DURING THE MORNING
TO EARLY AFTERNOON HOURS. TIMING OF THE FRONT AND DEPARTING UPPER
LEVEL FORCING TO OUR NORTHEAST SHOULD LIMIT THE THREAT FOR
SIGNIFICANT/DEEP CONVECTION IN MOST PLACES...EXCEPT FOR PERHAPS ONE
OR TWO STRONG TSRA ACROSS OUR FAR EAST AFTER 16Z RIGHT NEAR THE
CFRONT.
PLENTY OF LOW CLOUDS SHOULD FORM THEN LINGER IN THE COOLER/MOIST
UPSLOPE FLOW IN THE WAKE OF THE FRONT ACROSS THE ALLEGHENY PLATEAU
/KJST TO KBFD/...KEEPING TEMPS IN THE U60S TO LOWER 70S.
BKN...LAYERED CU AND ALTO CU WILL OCCUR ELSEWHERE WITH SCATTERED TO
NUMEROUS SHOWERS FOR SEVERAL HOURS ALONG AND IN ADVANCE OF THE
FRONT. HIGHS WILL BE BETWEEN 75-80F THROUGHOUT THE CENTRAL AND
SOUTHERN VALLEYS.
ADDITIONAL RAINFALL AMOUNTS TUESDAY WILL LIKELY AVERAGE UNDER 0.25
INCH IN MOST PLACES...BUT LOCATIONS SEEING A TSRA ACROSS THE SUSQ
VALLEY MAY SEE LOCALLY OVER 0.50 GIVEN THE NW EDGE OF 1.5-1.75 INCH
PWATS SLIDING ACROSS THE AREA AHEAD OF THE FRONT DURING THE
MORNING/MIDDAY HOURS.
TUESDAY AFTERNOON WILL FEATURE A DRYING TREND WITH A 10-20 MPH WEST
TO NW BREEZE AS A WELL-DEFINED DRY SLOT MOVES OVER THE REGION WITH
PWATS STEADILY DECREASING /TO BELOW 0.75 INCH ACROSS THE NW MTNS/
THROUGH THE AFTERNOON AND EVENING HOURS.
THE SOUTHERN...TAIL END OF A MID LEVEL THERMAL TROUGH WITH STEEP
850-500 MB LAPSE RATES WILL BRING A SEVERAL HOUR PERIOD OF CLOUDS
AND A LOW CHC FOR SHOWERS ACROSS THE NRN TIER COUNTIES LATER TUESDAY
NIGHT. RAINFALL AMOUNTS WILL BE LIGHT.
OTHERWISE...LOOK FOR GENERALLY PARTLY CLOUDY CONDITIONS WITH A
NORTHWEST BREEZE GRADUALLY DIMINISHING TO UNDER 7 KTS AFTER MIDNIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
POST FRONTAL THROUGH THURSDAY WITH A DRY AND COOL /FOR AUGUST/
PATTERN WITH ROCKY MOUNTAIN UPPER RIDGE AND DOWNSTREAM LONG WAVE
TROF FROM EASTERN CANADA TO THE MID ATLANTIC REGION. BOTH TUESDAY
AND WEDNESDAY MORNINGS LOOK VERY COOL ESPECIALLY ALONG THE
NORTHERN ZONES. FLOW TURNS SW BY FRIDAY AND THE WEEKEND FOR MILDER
TEMPERATURES AND A RETURN OF HIGHER HUMIDITY`S.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
EXPECT MAINLY VFR CONDITIONS TO PERSIST THROUGH THE REST OF TODAY
AND THROUGH THIS EVENING AT ALL TAF SITES WITH THE LONE EXCEPTION OF
KBFD...WHERE MVFR VSBYS AND PERHAPS PERIODS OF MVFR CIGS WILL
ACCOMPANY A LARGE AREA OF SHOWERS THAT HAVE RECENTLY SPREAD INTO THE
REGION FROM LAKE ERIE AND PTS WEST.
OUTSIDE OF THE NW MTNS...CONVECTION WILL BE ISOLATED AND BRIEF AS
WEAK RIDGING AT THE SFC AND ALOFT MOVES OVERHEAD.
WARM ADVECTION AND INCREASING DEEP LAYER MOISTURE AHEAD OF A STRONG
COLD FRONT WILL BRING DETERIORATING CIGS AND VSBYS LATE THIS EVENING
INTO THE MORNING HOURS TUESDAY. MVFR WITH POCKETS OF IFR WILL
ACCOMPANY SCTD TO NUMEROUS SHOWERS AND ISOLATED TSRA.
CIGS NEAR AND IN THE WAKE OF THE COLD FRONT WILL LIKELY DROP INTO
THE LIFR RANGE FOR AT LEAST A FEW HOURS TUESDAY MORNING /FROM 10Z ON
IN KBFD AND KJST/ AS THE COOL MOIST AIR IS LIFTED OVER THE WRN PENN
MTNS.
THE STRONG COLD FRONT WILL MOVE ACROSS THE REGION DURING THE MORNING
AND EARLY AFTERNOON HOURS TUESDAY. EXPECT BANDS OF SHOWERS AND
THUNDERSTORMS TO FORM. DYNAMICS LAG THE FRONT SOME...BUT STILL SOME
CONCERN FOR BRIEF...STRONG WIND GUSTS WITH ANY STORMS...ESP ACROSS
THE SUSQ RIVER VALLEY.
NORTHWEST BREEZE OF 10-15 KTS SUSTAINED FOLLOWS THE CFRONT TUESDAY
AFTERNOON AND EVENING BEFORE SUBSIDING A BIT TUESDAY NIGHT.
WINDY ON WED...AS DEEPER/COLDER AIR WORKS SOUTHWARD.
LOOKING AT DRY CONDITIONS AFT WED.
OUTLOOK...
WED-SAT...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...ROSS
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
736 AM EDT MON AUG 12 2013
.SYNOPSIS...
LOOK FOR A MILD AND INCREASINGLY HUMID DAY TODAY ACROSS THE
REGION...AHEAD OF THE ARRIVAL OF A STRONG COLD FRONT PASSAGE ON
TUESDAY. THERE WILL BE A COUPLE WEAK WEATHER DISTURBANCES MOVING
ACROSS THE AREA WHICH COULD TOUCH OFF BRIEF SHOWERS AND
THUNDERSTORMS TODAY...BUT MOST OF THE AREA WILL BE FREE OF
SIGNIFICANT RAINFALL. BEHIND THE COLD FRONT ON TUESDAY...ABNORMALLY
COOL DRY AIR SHOULD OVERTAKE THE REGION...PROVIDING SEVERAL
PLEASANT BUT RELATIVELY COOL DAYS. THE DEEP TROUGH AND COOL AIR
MODIFY AND WEAKEN FRIDAY AND INTO THE COMING WEEKEND. TEMPERATURES
SHOULD TREND BACK TOWARD NORMAL FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
GENERAL DECREASE IN ACTIVITY THE LAST COUPLE HOURS...ACTIVITY
CONFINED TO SE QUARTER OF THE CWA. STORMS HAVE PRODUCED HEAVY
DOWNPOURS BUT MOVING JUST FAST ENOUGH TO PRECLUDE ANY FLOODING.
SCAP1 IN SCHUYLKILL COUNTY REPORTED .47 IN 35 MINUTES EARLIER THIS
MORNING. LATEST RUC AND HRRR SHOWS MOST OF THE CONVECTION
TAPERING OFF IN THE NEXT COUPLE HOURS. AFTER LOW CLOUDS DIMINISH
THIS MORNING THE REGION WILL SEE VARIABLE CLOUDS WITH A SLIGHT
CHANCE OF SHOWERS OR THUNDERSHOWERS...WITH THE HIGHEST CHANCES
OVER THE NW AND SE PORTIONS OF THE CWA...BUT SIMILAR TO
SUNDAY...MOST OF THE REGION WILL MISS OUT ON ANY SIGNIFICANT
RAINFALL. TEMPERATURES WILL BE CLOSE TO AVERAGE...THOUGH IT WILL
BE MORE HUMID AHEAD OF THE APPROACHING FRONT ARRIVING ON TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
THE STRONG FRONTAL SYSTEM WILL BECOME THE PRIMARY WEATHER FOCUS.
FRONTAL TIMING SUGGESTS CHANCE RAIN AND THUNDER COMES UP AFTER
MIDNIGHT IN WESTERN AREAS MOVING EASTWARD WITH TIME DURING
OVERNIGHT INTO TUESDAY MORNING. TIMING OF FRONTAL PASSAGE COULD
BE SUCH THAT TUESDAY AFTERNOON COULD TURN OUT DRIER...AND FORECAST
SHOWS POPS LOWERING IN THE SECOND HALF OF AFTERNOON WEST TO EAST.
QPF LOOKS RATHER LIGHT WITH PW PLUME NOT ALL THAT IMPRESSIVE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
POST FRONTAL THROUGH THURSDAY WITH A DRY AND COOL /FOR AUGUST/
PATTERN WITH ROCKY MOUNTAIN UPPER RIDGE AND DOWNSTREAM LONG WAVE
TROF FROM EASTERN CANADA TO THE MID ATLANTIC REGION. BOTH TUESDAY
AND WEDNESDAY MORNINGS LOOK VERY COOL ESPECIALLY ALONG THE
NORTHERN ZONES. FLOW TURNS SW BY FRIDAY AND THE WEEKEND FOR MILDER
TEMPERATURES AND A RETURN OF HIGHER HUMIDITY`S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
FOG STARTING TO LIFT...SHOULD BE GONE BY 14Z.
WIDE RANGE OF CONDITIONS. UNV WENT CLEAR AROUND 5 AM...THEN
DENSE FOG FOR A BRIEF TIME.
MORE DENSE FOG TO THE SOUTH. VAD WINDS SUGGEST COOL AIR LESS
THAN 6000 DEEP THE LAST FEW DAYS.
AS BEEN THE CASE THIS SUMMER...SHOWERS FORM ALMOST EVERY DAY.
CURRENT ACTIVITY IS NOW MAINLY EAST OF OUR AREA.
BY MID MORNING...EXPECT MAINLY VFR CONDITIONS. THERE WILL STILL
BE A CHC OF SHOWERS AND PERHAPS A FEW THUNDERTORMS ACROSS THE
SOUTH THIS AFT AND EVENING.
AT THE SAME TIME...SOME SHOWERS AND STORMS COULD FORM
ACROSS NORTHERN PA LATER TODAY. OVERALL A COMPLEX PATTERN.
STRONG COLD FRONT TO MOVE ACROSS THE REGION LATE TUESDAY.
EXPECT BANDS OF SHOWERS AND THUNDERSTORMS TO FORM. DYNAMICS
LAG THE FRONT SOME...BUT STILL SOME CONCERN FOR STRONG WINDS
WITH ANY STORMS.
WINDY ON WED...AS COLDER AIR WORKS SOUTHWARD.
LOOKING AT DRY CONDITIONS AFT WED.
OUTLOOK...
TUE...VFR/MVFR WITH SCT SHOWERS AND TSTMS.
WED-FRI...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
547 AM EDT MON AUG 12 2013
.SYNOPSIS...
LOOK FOR A MILD AND INCREASINGLY HUMID DAY TODAY ACROSS THE
REGION...AHEAD OF THE ARRIVAL OF A STRONG COLD FRONT PASSAGE ON
TUESDAY. THERE WILL BE A COUPLE WEAK WEATHER DISTURBANCES MOVING
ACROSS THE AREA WHICH COULD TOUCH OFF BRIEF SHOWERS AND
THUNDERSTORMS TODAY...BUT MOST OF THE AREA WILL BE FREE OF
SIGNIFICANT RAINFALL. BEHIND THE COLD FRONT ON TUESDAY...ABNORMALLY
COOL DRY AIR SHOULD OVERTAKE THE REGION...PROVIDING SEVERAL
PLEASANT BUT RELATIVELY COOL DAYS. THE DEEP TROUGH AND COOL AIR
MODIFY AND WEAKEN FRIDAY AND INTO THE COMING WEEKEND. TEMPERATURES
SHOULD TREND BACK TOWARD NORMAL FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
GENERAL DECREASE IN ACTIVITY THE LAST COUPLE HOURS...ACTIVITY
CONFINED TO SE QUARTER OF THE CWA. STORMS HAVE PRODUCED HEAVY
DOWNPOURS BUT MOVING JUST FAST ENOUGH TO PRECLUDE ANY FLOODING.
SCAP1 IN SCHUYLKILL COUNTY REPORTED .47 IN 35 MINUTES EARLIER THIS
MORNING. LATEST RUC AND HRRR SHOWS MOST OF THE CONVECTION
TAPERING OFF IN THE NEXT COUPLE HOURS. AFTER LOW CLOUDS DIMINISH
THIS MORNING THE REGION WILL SEE VARIABLE CLOUDS WITH A SLIGHT
CHANCE OF SHOWERS OR THUNDERSHOWERS...WITH THE HIGHEST CHANCES
OVER THE NW AND SE PORTIONS OF THE CWA...BUT SIMILAR TO
SUNDAY...MOST OF THE REGION WILL MISS OUT ON ANY SIGNIFICANT
RAINFALL. TEMPERATURES WILL BE CLOSE TO AVERAGE...THOUGH IT WILL
BE MORE HUMID AHEAD OF THE APPROACHING FRONT ARRIVING ON TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
THE STRONG FRONTAL SYSTEM WILL BECOME THE PRIMARY WEATHER FOCUS.
FRONTAL TIMING SUGGESTS CHANCE RAIN AND THUNDER COMES UP AFTER
MIDNIGHT IN WESTERN AREAS MOVING EASTWARD WITH TIME DURING
OVERNIGHT INTO TUESDAY MORNING. TIMING OF FRONTAL PASSAGE COULD
BE SUCH THAT TUESDAY AFTERNOON COULD TURN OUT DRIER...AND FORECAST
SHOWS POPS LOWERING IN THE SECOND HALF OF AFTERNOON WEST TO EAST.
QPF LOOKS RATHER LIGHT WITH PW PLUME NOT ALL THAT IMPRESSIVE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
POST FRONTAL THROUGH THURSDAY WITH A DRY AND COOL /FOR AUGUST/
PATTERN WITH ROCKY MOUNTAIN UPPER RIDGE AND DOWNSTREAM LONG WAVE
TROF FROM EASTERN CANADA TO THE MID ATLANTIC REGION. BOTH TUESDAY
AND WEDNESDAY MORNINGS LOOK VERY COOL ESPECIALLY ALONG THE
NORTHERN ZONES. FLOW TURNS SW BY FRIDAY AND THE WEEKEND FOR MILDER
TEMPERATURES AND A RETURN OF HIGHER HUMIDITY`S.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
WIDE RANGE OF CONDITIONS. UNV IS MAINLY CLR NOW...SOME LOWER
CIGS AND DENSE FOG TO THE SOUTH. VAD WINDS SUGGEST COOL AIR
LESS THAN 6000 DEEP THE LAST FEW DAYS. 09Z TAFS ADJUSTED
FOR CURRENT CONDITIONS.
EARLIER DISCUSSION BELOW.
AS BEEN THE CASE THIS SUMMER...SHOWERS FORM ALMOST EVERY DAY.
CURRENT ACTIVITY IS NOW MAINLY EAST OF INTERSTATE 99...WITH
A FEW HEAVY DOWNPOURS AND A RUMBLE OF THUNDER. ALSO ACROSS
THE SOUTHERN AREAS IS SOME FOG AND LOWER CIGS. STILL MAINLY
CLEAR TO THE NORTH. EXPECT LITTLE CHANGE BEFORE MID MORNING.
AFTER MID MORNING...EXPECT MAINLY VFR CONDITIONS. THERE WILL
STILL BE A CHC OF SHOWERS AND PERHAPS A FEW THUNDERTORMS
ACROSS THE SOUTH THIS AFT AND EVENING.
AT THE SAME TIME...SOME SHOWERS AND STORMS COULD FORM
ACROSS NORTHERN PA LATER TODAY. OVERALL A COMPLEX PATTERN.
STRONG COLD FRONT TO MOVE ACROSS THE REGION LATE TUESDAY.
EXPECT BANDS OF SHOWERS AND THUNDERSTORMS TO FORM. DYNAMICS
LAG THE FRONT SOME...BUT STILL SOME CONCERN FOR STRONG WINDS
WITH ANY STORMS.
WINDY ON WED...AS COLDER AIR WORKS SOUTHWARD.
LOOKING AT DRY CONDITIONS AFT WED.
OUTLOOK...
TUE...VFR/MVFR WITH SCT SHOWERS AND TSTMS.
WED-FRI...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
523 AM EDT MON AUG 12 2013
.SYNOPSIS...
LOOK FOR A MILD AND INCREASINGLY HUMID DAY TODAY ACROSS THE
REGION...AHEAD OF THE ARRIVAL OF A STRONG COLD FRONT PASSAGE ON
TUESDAY. THERE WILL BE A COUPLE WEAK WEATHER DISTURBANCES MOVING
ACROSS THE AREA WHICH COULD TOUCH OFF BRIEF SHOWERS AND
THUNDERSTORMS TODAY...BUT MOST OF THE AREA WILL BE FREE OF
SIGNIFICANT RAINFALL. BEHIND THE COLD FRONT ON TUESDAY...ABNORMALLY
COOL DRY AIR SHOULD OVERTAKE THE REGION...PROVIDING SEVERAL
PLEASANT BUT RELATIVELY COOL DAYS. THE DEEP TROUGH AND COOL AIR
MODIFY AND WEAKEN FRIDAY AND INTO THE COMING WEEKEND. TEMPERATURES
SHOULD TREND BACK TOWARD NORMAL FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
GENERAL DECREASE IN ACTIVITY THE LAST COUPLE HOURS...ACTIVITY
CONFINED TO SE QUARTER OF THE CWA. STORMS HAVE PRODUCED HEAVY
DOWNPOURS BUT MOVING JUST FAST ENOUGH TO PRECLUDE ANY FLOODING.
SCAP1 IN SCHUYLKILL COUNTY REPORTED .47 IN 35 MINUTES EARLIER THIS
MORNING. LATEST RUC AND HRRR SHOWS MOST OF THE CONVECTION
TAPERING OFF IN THE NEXT COUPLE HOURS. AFTER LOW CLOUDS DIMINISH
THIS MORNING THE REGION WILL SEE VARIABLE CLOUDS WITH A SLIGHT
CHANCE OF SHOWERS OR THUNDERSHOWERS...WITH THE HIGHEST CHANCES
OVER THE NW AND SE PORTIONS OF THE CWA...BUT SIMILAR TO
SUNDAY...MOST OF THE REGION WILL MISS OUT ON ANY SIGNIFICANT
RAINFALL. TEMPERATURES WILL BE CLOSE TO AVERAGE...THOUGH IT WILL
BE MORE HUMID AHEAD OF THE APPROACHING FRONT ARRIVING ON TUESDAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
THE STRONG FRONTAL SYSTEM WILL BECOME THE PRIMARY WEATHER FOCUS. FRONTAL
TIMING SUGGESTS CHANCE RAIN AND THUNDER COMES UP AFTER MIDNIGHT IN
WESTERN AREAS MOVING EASTWARD WITH TIME DURING OVERNIGHT INTO
TUESDAY MORNING. TIMING OF FRONTAL PASSAGE COULD BE SUCH THAT TUESDAY
AFTERNOON COULD TURN OUT DRIER...AND FORECAST SHOWS POPS LOWERING
IN THE SECOND HALF OF AFTERNOON WEST TO EAST. QPF LOOKS RATHER
LIGHT WITH PW PLUME NOT ALL THAT IMPRESSIVE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
POST FRONTAL THROUGH THURSDAY WITH A DRY AND COOL /FOR AUGUST/
PATTERN WITH ROCKY MOUNTAIN UPPER RIDGE AND DOWNSTREAM LONG WAVE
TROF FROM EASTERN CANADA TO THE MID ATLANTIC REGION. BOTH TUESDAY
AND WEDNESDAY MORNINGS LOOK VERY COOL ESPECIALLY ALONG THE
NORTHERN ZONES. FLOW TURNS SW BY FRIDAY AND THE WEEKEND FOR MILDER
TEMPERATURES AND A RETURN OF HIGHER HUMIDITY`S.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
AS BEEN THE CASE THIS SUMMER...SHOWERS FORM ALMOST EVERY DAY.
CURRENT ACTIVITY IS NOW MAINLY EAST OF INTERSTATE 99...WITH
A FEW HEAVY DOWNPOURS AND A RUMBLE OF THUNDER. ALSO ACROSS
THE SOUTHERN AREAS IS SOME FOG AND LOWER CIGS. STILL MAINLY
CLEAR TO THE NORTH. EXPECT LITTLE CHANGE BEFORE MID MORNING.
AFTER MID MORNING...EXPECT MAINLY VFR CONDITIONS. THERE WILL
STILL BE A CHC OF SHOWERS AND PERHAPS A FEW THUNDERTORMS
ACROSS THE SOUTH THIS AFT AND EVENING.
AT THE SAME TIME...SOME SHOWERS AND STORMS COULD FORM
ACROSS NORTHERN PA LATER TODAY. OVERALL A COMPLEX PATTERN.
STRONG COLD FRONT TO MOVE ACROSS THE REGION LATE TUESDAY.
EXPECT BANDS OF SHOWERS AND THUNDERSTORMS TO FORM. DYNAMICS
LAG THE FRONT SOME...BUT STILL SOME CONCERN FOR STRONG WINDS
WITH ANY STORMS.
WINDY ON WED...AS COLDER AIR WORKS SOUTHWARD.
LOOKING AT DRY CONDITIONS AFT WED.
OUTLOOK...
TUE...VFR/MVFR WITH SCT SHOWERS AND TSTMS.
WED-FRI...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
221 AM EDT MON AUG 12 2013
.SYNOPSIS...
LOOK FOR A MILD AND INCREASINGLY HUMID DAY TODAY ACROSS THE
REGION...AHEAD OF THE ARRIVAL OF A STRONG COLD FRONT PASSAGE ON
TUESDAY. THERE WILL BE A COUPLE WEAK WEATHER DISTURBANCES MOVING
ACROSS THE AREA WHICH COULD TOUCH OFF BRIEF SHOWERS AND
THUNDERSTORMS TODAY...BUT MOST OF THE AREA WILL BE FREE OF
SIGNIFICANT RAINFALL. BEHIND THE COLD FRONT ON TUESDAY...ABNORMALLY
COOL DRY AIR SHOULD OVERTAKE THE REGION...PROVIDING SEVERAL
PLEASANT BUT RELATIVELY COOL DAYS. THE DEEP TROUGH AND COOL AIR
MODIFY AND WEAKEN FRIDAY AND INTO THE COMING WEEKEND. TEMPERATURES
SHOULD TREND BACK TOWARD NORMAL FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
TRACKING SEVERAL AREAS OF CONVECTION MOVING ACROSS SOUTHERN ZONES
EARLY THIS MORNING. STORMS ARE PUTTING DOWN SOME HEAVY DOWNPOURS
BUT FORTUNATELY THEY ARE MOVING FAST ENOUGH TO PREVENT SIGNIFICANT
ACCUMULATIONS. LOOKING AT LATEST RUC AND HRRR RUNS SHOWS MOST OF
THE CONVECTION TAPERING OFF FOR ALL BUT THE EXTREME SW CORNER OF
THE CWA WHERE SHOWERS WILL LIKELY PERSIST UNTIL AFTER SUNRISE.
AFTER LOW CLOUDS DIMINISH THIS MORNING THE REGION WILL SEE
VARIABLE CLOUDS WITH A SLIGHT CHANCE OF SHOWERS OR
THUNDERSHOWERS...WITH THE HIGHEST CHANCES OVER THE NW AND SE
PORTIONS OF THE CWA...BUT SIMILAR TO SUNDAY...MOST OF THE REGION WILL
MISS OUT ON ANY SIGNIFICANT RAINFALL. TEMPERATURES WILL BE CLOSE TO
AVERAGE...THOUGH IT WILL BE MORE HUMID AHEAD OF THE APPROACHING
FRONT ARRIVING ON TUESDAY.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
THE STRONG FRONTAL SYSTEM WILL BECOME AN ISSUE OVERNIGHT MONDAY
INTO TUESDAY. FRONTAL TIMING SUGGESTS CHANCE RAIN AND THUNDER
COMES UP AFTER MIDNIGHT IN WESTERN AREAS AND STROLLS EASTWARD WITH
TIME DURING OVERNIGHT INTO TUESDAY MORNING. IF THE FRONT SPEEDS UP
TUESDAY AFTERNOON COULD TURN OUT OKAY. TRIED TO SHOW POPS LOWERING
IN THE SECOND HALF OF AFTERNOON WEST TO EAST.
ALWAYS A POP PROBLEMS AS SREF HAS THE PATTERN OF DECREASED POPS
BUT IT IS SO WET BIASED ONE CANNOT USE IT EFFECTIVELY IN GRIDS.
THE GEFS SHOWS LOWER POPS AFTER 18Z TUESDAY AS DO ALL THE
MODELS...NAM/GFS. SUSPECT PW TELLS US TWO IMPORTANT THINGS 1) NOT
GOING TO BE A BIG RAIN EVENT AND 2) PW DROPS IN AFTERNOON IMPLYING
THE AFTERNOON COULD BE RAIN FREE IN WEST. POPS REFLECT THIS
THINKING AS BEST AS PRACTICABLE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
GENERALLY COSMETIC CHANGES MADE TO PREVIOUS EXTENDED FORECAST
TODAY AS PATTERN WILL BE DOMINATED BY THE ROCKY MOUNTAIN UPPER
RIDGE AND DOWNSTREAM LONG WAVE TROF FROM EASTERN CANADA TO THE MID
ATLANTIC REGION THIS WEEK.
BEST CHANCE OF PRECIPITATION WILL COME FROM A FRONTAL SYSTEM
MONDAY NIGHT AND TUESDAY BEFORE THE MEAN UPPER TROF AXIS SETTLES
EAST OF THE AREA FOR THE LATTER HALF OF THIS WEEK. AS PREVIOUSLY
MENTIONED...THE BIGGEST IMPACT WILL BE A FRESH SHOT OF DRIER AND
COOLER AIR FOR THE MIDDLE OF THE WEEK AS TEMPERATURES DROP BELOW
AVERAGE ON WED AND THU. FLOW BEGINS TO TURN SW LATE IN THE PERIOD
FOR SOME MODERATION AS THE WEEKEND APPROACHES.
LATE IN THE PERIOD...WESTERN ATLANTIC UPPER RIDGE RETROGRADES AND
AMPLIFIES OVER BERMUDA. THIS WILL HELP TO SHARPEN THE EAST COAST
TROF AXIS AND DIRECT DEEPER LAYER MOISTURE NORTHWARD INTO THE MID
ATLANTIC REGION NEXT WEEKEND. HAVE INTRODUCED SHOWER CHANCES AS A
RESULT...MAINLY ON SUNDAY. GULF COAST TROPICAL DEVELOPMENT IS
POSSIBLE WITH THIS SURGE OF MOISTURE...SO WE`LL BE WATCHING THIS
WITH INTEREST AS THE WEEK PROGRESSES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS BEEN THE CASE THIS SUMMER...SHOWERS FORM ALMOST EVERY DAY.
CURRENT ACTIVITY IS NOW MAINLY EAST OF INTERSTATE 99...WITH
A FEW HEAVY DOWNPOURS AND A RUMBLE OF THUNDER. ALSO ACROSS
THE SOUTHERN AREAS IS SOME FOG AND LOWER CIGS. STILL MAINLY
CLEAR TO THE NORTH. EXPECT LITTLE CHANGE BEFORE MID MORNING.
AFTER MID MORNING...EXPECT MAINLY VFR CONDITIONS. THERE WILL
STILL BE A CHC OF SHOWERS AND PERHAPS A FEW THUNDERTORMS
ACROSS THE SOUTH THIS AFT AND EVENING.
AT THE SAME TIME...SOME SHOWERS AND STORMS COULD FORM
ACROSS NORTHERN PA LATER TODAY. OVERALL A COMPLEX PATTERN.
STRONG COLD FRONT TO MOVE ACROSS THE REGION LATE TUESDAY.
EXPECT BANDS OF SHOWERS AND THUNDERSTORMS TO FORM. DYNAMICS
LAG THE FRONT SOME...BUT STILL SOME CONCERN FOR STRONG WINDS
WITH ANY STORMS.
WINDY ON WED...AS COLDER AIR WORKS SOUTHWARD.
LOOKING AT DRY CONDITIONS AFT WED.
OUTLOOK...
TUE...VFR/MVFR WITH SCT SHOWERS AND TSTMS.
WED-FRI...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS/DEVOIR
AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
200 AM EDT MON AUG 12 2013
.SYNOPSIS...
LOOK FOR A MILD AND INCREASINGLY HUMID DAY TODAY ACROSS THE
REGION...AHEAD OF THE ARRIVAL OF A STRONG COLD FRONT PASSAGE ON
TUESDAY. THERE WILL BE A COUPLE WEAK WEATHER DISTURBANCES MOVING
ACROSS THE AREA WHICH COULD TOUCH OFF BRIEF SHOWERS AND
THUNDERSTORMS TODAY...BUT MOST OF THE AREA WILL BE FREE OF
SIGNIFICANT RAINFALL. BEHIND THE COLD FRONT ON TUESDAY...ABNORMALLY
COOL DRY AIR SHOULD OVERTAKE THE REGION...PROVIDING SEVERAL
PLEASANT BUT RELATIVELY COOL DAYS. THE DEEP TROUGH AND COOL AIR
MODIFY AND WEAKEN FRIDAY AND INTO THE COMING WEEKEND. TEMPERATURES
SHOULD TREND BACK TOWARD NORMAL FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
TRACKING SEVERAL AREAS OF CONVECTION MOVING ACROSS SOUTHERN ZONES
EARLY THIS MORNING. STORMS ARE PUTTING DOWN SOME HEAVY DOWNPOURS
BUT FORTUNATELY THEY ARE MOVING FAST ENOUGH TO PREVENT SIGNIFICANT
ACCUMULATIONS. LOOKING AT LATEST RUC AND HRRR RUNS SHOWS MOST OF
THE CONVECTION TAPERING OFF FOR ALL BUT THE EXTREME SW CORNER OF
THE CWA WHERE SHOWERS WILL LIKELY PERSIST UNTIL AFTER SUNRISE.
AFTER LOW CLOUDS DIMINISH THIS MORNING THE REGION WILL SEE
VARIABLE CLOUDS WITH A SLIGHT CHANCE OF SHOWERS OR
THUNDERSHOWERS...WITH THE HIGHEST CHANCES OVER THE NW AND SE
PORTIONS OF THE CWA...BUT SIMILAR TO SUNDAY...MOST OF THE REGION WILL
MISS OUT ON ANY SIGNIFICANT RAINFALL. TEMPERATURES WILL BE CLOSE TO
AVERAGE...THOUGH IT WILL BE MORE HUMID AHEAD OF THE APPROACHING
FRONT ARRIVING ON TUESDAY.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
THE STRONG FRONTAL SYSTEM WILL BECOME AN ISSUE OVERNIGHT MONDAY
INTO TUESDAY. FRONTAL TIMING SUGGESTS CHANCE RAIN AND THUNDER
COMES UP AFTER MIDNIGHT IN WESTERN AREAS AND STROLLS EASTWARD WITH
TIME DURING OVERNIGHT INTO TUESDAY MORNING. IF THE FRONT SPEEDS UP
TUESDAY AFTERNOON COULD TURN OUT OKAY. TRIED TO SHOW POPS LOWERING
IN THE SECOND HALF OF AFTERNOON WEST TO EAST.
ALWAYS A POP PROBLEMS AS SREF HAS THE PATTERN OF DECREASED POPS
BUT IT IS SO WET BIASED ONE CANNOT USE IT EFFECTIVELY IN GRIDS.
THE GEFS SHOWS LOWER POPS AFTER 18Z TUESDAY AS DO ALL THE
MODELS...NAM/GFS. SUSPECT PW TELLS US TWO IMPORTANT THINGS 1) NOT
GOING TO BE A BIG RAIN EVENT AND 2) PW DROPS IN AFTERNOON IMPLYING
THE AFTERNOON COULD BE RAIN FREE IN WEST. POPS REFLECT THIS
THINKING AS BEST AS PRACTICABLE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
GENERALLY COSMETIC CHANGES MADE TO PREVIOUS EXTENDED FORECAST
TODAY AS PATTERN WILL BE DOMINATED BY THE ROCKY MOUNTAIN UPPER
RIDGE AND DOWNSTREAM LONG WAVE TROF FROM EASTERN CANADA TO THE MID
ATLANTIC REGION THIS WEEK.
BEST CHANCE OF PRECIPITATION WILL COME FROM A FRONTAL SYSTEM
MONDAY NIGHT AND TUESDAY BEFORE THE MEAN UPPER TROF AXIS SETTLES
EAST OF THE AREA FOR THE LATTER HALF OF THIS WEEK. AS PREVIOUSLY
MENTIONED...THE BIGGEST IMPACT WILL BE A FRESH SHOT OF DRIER AND
COOLER AIR FOR THE MIDDLE OF THE WEEK AS TEMPERATURES DROP BELOW
AVERAGE ON WED AND THU. FLOW BEGINS TO TURN SW LATE IN THE PERIOD
FOR SOME MODERATION AS THE WEEKEND APPROACHES.
LATE IN THE PERIOD...WESTERN ATLANTIC UPPER RIDGE RETROGRADES AND
AMPLIFIES OVER BERMUDA. THIS WILL HELP TO SHARPEN THE EAST COAST
TROF AXIS AND DIRECT DEEPER LAYER MOISTURE NORTHWARD INTO THE MID
ATLANTIC REGION NEXT WEEKEND. HAVE INTRODUCED SHOWER CHANCES AS A
RESULT...MAINLY ON SUNDAY. GULF COAST TROPICAL DEVELOPMENT IS
POSSIBLE WITH THIS SURGE OF MOISTURE...SO WE`LL BE WATCHING THIS
WITH INTEREST AS THE WEEK PROGRESSES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
PRIMARILY VFR CONDITIONS PREVAIL ACROSS CENTRAL PA THIS
EVENING...WITH ISOLATED SHOWERS AND A RARE TSTM DRIFTING W-E
ALONG THE PA TURNPIKE BRINGING SHORT-LIVED REDUCTIONS. THESE
SHOULD DIMINISH DURING THE EARLY MORNING HOURS.
PATCHY MAINLY MVFR FOG /ISO IFR/ WILL DEVELOP BETWEEN 06Z-09Z AND
DISSOLVE THROUGH MID MORNING. CHC OF LOWER STRATOCU ACROSS SE
LATE.
FOR MONDAY...PRIMARILY VFR CONDITIONS CONTINUE. CANNOT RULE OUT
STRAY SHOWERS AND/OR ISOLATED THUNDERSTORMS...BUT MAJORITY OF THE
DAY WILL BE DRY IN ANY ONE LOCATION. MODELS HINTING AT HIGHER POPS
IN THE SE DURING SECOND HALF OF AFTERNOON BASED ON INCREASING
INSTABILITY AND HINTS OF QPF IN JUST ABOUT ALL MODELS.
A STRONG FRONTAL SYSTEM SLIDES IN FROM THE NW OVERNIGHT MONDAY
INTO TUESDAY...WITH CONDITIONS DETERIORATING. AREA OF RAIN AND SCT
THUNDER WORKS IN FROM THE NW MON NIGHT...EXITING SE BY TUE AFT.
OUTLOOK...
MON...PRIMARILY VFR. ISO SHRA/TSTM...HIGHEST CHANCE IN SE LATE AFT.
MON NIGHT...DETERIORATING CONDITIONS FROM NW. SHOWERS/TSTMS LKLY
MAINLY OVER THE NW AIRFIELDS. MAINLY VFR SE.
TUE...VFR/MVFR WITH SCT SHOWERS AND TSTMS...ESP BEFORE NOON.
WED-FRI...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS/DEVOIR
AVIATION...RXR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
214 PM MDT MON AUG 12 2013
.SHORT TERM...THIS EVENING THROUGH TUESDAY NIGHT
ISSUED AT 213 PM MDT MON AUG 12 2013
A LARGE SCALE BLOCKING PATTERN DOMINATES OVER NORTH
AMERICA WITH UPPER LEVEL TROUGHING OVER THE EASTERN HALF OF THE
CONTINENT AND A RIDGE ALONG THE CONTDVD. THE DAKOTAS REMAIN ON THE
COOL SIDE OF THE FRONT WHICH EXTENDS FROM CENTRAL MONTANA
SOUTHEASTWARD INTO THE CENTRAL PLAINS. SATELLITE IMAGERY SHOWS A
FAIRLY STRONG BUT DRY SHORT WAVE ROTATING SOUTHWARD INTO THE
NORTHERN PLAINS FROM CANADA THIS AFTERNOON. A WEAKER SYSTEM IS
FAINTLY VISIBLE IN THE WATER VAPOR LOOP MOVING SOUTHEASTWARD THROUGH
THE WESTERN DAKOTAS. AT THE SURFACE...RIDGING OVER THE EASTERN
DAKOTAS SET UP A RETURN FLOW OVER WESTERN SOUTH DAKOTA RESULTING IN
A BAND OF HIGHER DEQPOINTS EXTENDING INTO NORTHWEST SOUTH DAKOTA.
PLENTY OF INSTABILITY APPEARS TO BE AVAILABLE WITH SBCAPES IN EXCESS
OF 2000 J/KG OVER MUCH OF THE WEST...HOWEVER 0-6KM SHEAR WAS LESS
THAN 40 KTS OVER THE MOST OF WESTERN SOUTH DAKOTA. LITTLE OR NO
DEVELOPMENT HAD OCCURRED EAST OF THE HIGH TERRAIN OF CENTRAL/EASTERN
WYOMING AS OF 19Z.
TONIGHT...CHANCE POPS WILL REMAIN IN THE FORECAST FOR TONIGHT DUE TO
PLENTY OF INSTABILITY AND POSSIBLE WEAK UPPER LEVEL SUPPORT. AS WEAK
DISTURBANCES ALOFT CROSSES THE REGION TONIGHT AND THE LOW LEVEL JET
INTENSIFIES OVER THE AREA THIS EVENING...THE COVERAGE OF STORMS
COULD EXPAND SOME INTO THE OVERNIGHT HOURS...ESPECIALLY EAST OF THE
BLACK HILLS. STORM MOTION THIS EVENING SHOULD BE VERY SLOW...SO IF
SIGNIFICANT CONVECTION DOES DEVELOP LOCALLY HEAVY RAINFALL
ACCUMULATIONS ARE A POSSIBILITY.
TUESDAY AND TUESDAY NIGHT...THE MODELS CALL FOR THE RIDGE TO REMAIN
OVER THE EEASTERN DAKOTAS AND LEE SIDE TROUGHING TO REMAIN OVER
EASTERN WYOMING. THEREFORE DAILY CHANCES FOR SHOWERS AND STORMS WILL
STAY IN THE FORECAST FOR THE NEXT SEVERAL DAYS. THUNDERSTORMS WHICH
DEVELOP LATE TONIGHT COULD PERSIST WELL INTO THE DAYTIME HOURS
TUESDAY SUPPORTED BY CONTINUED INSTABILITY AND SEVERAL ADDITIONAL
WEAK UPPER LEVEL IMPULSES CROSSING THE FORECAST AREA. ISOLATED
STRONG TO SEVERE STORMS ARE AGAIN POSSIBLE...MAINLY FOR THE
AFTERNOON AND EVENING HOURS.
&&
.LONG TERM...WEDNESDAY THROUGH MONDAY
ISSUED AT 213 PM MDT MON AUG 12 2013
MEAN WESTERN NOAM RIDGING TO REMAIN IN THE
PERIOD...WITH DOWNSTREAM MEAN NEGATIVE HEIGHT ANOMALIES LINGERING IN
EASTERN NOAM. ALTHOUGH A BRIEF REMOVAL OF THE PERSISTENT EASTERN
NOAM UPPER TROUGH WILL SUPPORT A BRIEF PERIOD OF LOCAL PROGRESSIVE
FLOW. NE PAC MEAN TROUGHING WILL CONTINUE TO SUPPORT SUBTLE IMPULSES
IN THE FLOW...WITH A MORE SUBSTANTIAL WAVE POSSIBLE TOWARD THE END
OF THIS WEEKEND. BEFOREHAND...A LINGERING STALLED BAROCLINIC ZONE
WILL PROVIDE A PATHWAY FOR PERTURBED WNW FLOW THROUGH MID WEEK. THE
NE PAC PERSISTENT UPPER TROUGH IS FORECAST TO CYCLE IN ALL
DETERMINISTIC MODELS...WITH UPPER RIDGING EXPECTED OVER THE NORTHERN
PLAINS FRIDAY THROUGH MUCH OF THE WEEKEND. THERE IS UNCERTAINTY IN
THE STRENGTH/PATH/AND LOCAL EFFECT OF THE EXPECTED EJECTING UPPER
TROUGH...WITH MODELS TRENDING FARTHER NORTH AND SHEARING THIS WAVE AS
IT PROGRESSES EAST...MOST PRONOUNCED IN THE ECMWF. THIS WOULD
EFFECTIVELY SHIFT THE REGION INTO ACTIVE SW FLOW WITH GENERALLY FAST
FLOW ON THE EDGE OF THE NORTHERN FA...SUPPORTING CONVECTIVE CHANCES
GIVEN A DEEP MOISTURE AXIS OVER THE REGION. FAIRLY WARM TEMPS WOULD
BE EXPECTED AS THE UPPER RIDGE TILTS OVER THE REGION...DIFFERENT
FROM PREVIOUS RUNS WHICH SUPPORTED A WESTERN BIAS TO THE WESTERN
CONUS RIDGE GIVEN A STRONGER EASTERN NOAM NEGATIVE HEIGHT ANOMALY.
HENCE...WILL SIDE WITH THE MIDDLE TO WARMER SIDE OF GUIDANCE FOR NOW
IN THE LATER PERIODS...WITH LOW CHANCES FOR PRECIP AT THE END OF THE
PERIOD GIVEN THE PROGGED ACTIVE FLOW REGIME...REMAINING COOLER ON
THE FRONT END OF THE PERIOD ALSO WITH LINGERING PRECIP CHANCES FOR
PERTURBED NW FLOW.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON
ISSUED AT 213 PM MDT MON AUG 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE PERIOD
SAVE IN AN NEAR SCT TS THIS AFTERNOON AND TONIGHT. MVFR/IFR CIGS
WILL BE POSSIBLE ONCE AGAIN TOWARD DAWN OVER THE EASTERN FA...WITH
EASTERLY FLOW POSSIBLY PUSHING STRATUS BACK INTO THE EASTERN BH
FOOTHILLS TUE MORNING. DID HINT AT THIS IN THE RAP TAF.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...CARPENTER
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1141 AM MDT MON AUG 12 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 308 AM MDT MON AUG 12 2013
CURRENT SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY STRETCHING FROM
CENTRAL MT TO SOUTHEASTERN WY AND THEN EASTWARD ACROSS NEB.
WEAKENING HIGH PRESSURE REMAINS OVER SOUTH CENTRAL CANADA. UPPER
LEVEL ANALYSIS CONTINUES TO SHOW HAS LARGE SCALE TROF OVER THE
GREAT LAKES AND NORTHEASTERN CONUS...WITH AN UPPER LOW ALONG THE
PACIFIC NW COAST. NEGATIVELY TILTED RIDGE REMAINS ACROSS THE
ROCKIES INTO THE SOUTHERN PLAINS. WEAK WEST TO NORTHWEST FLOW
ALOFT IS IN PLACE OVER THE NORTHERN PLAINS. EARLIER SHOWERS OVER
PORTIONS OF THE AREA HAVE DISSIPATED. SKIES ARE VARIABLY
CLOUDY...WITH PATCHY AREAS OF LOW CLOUDS TOWARD CENTRAL SD. TEMPS
ARE IN THE MID 50S TO MID 60S WITH LIGHT WINDS IN MOST AREAS.
DAILY CHANCES FOR SHOWERS AND STORMS WILL CONTINUE FOR THE NEXT
SEVERAL DAYS...WITH THE BEST CHANCES IN THE NEAR TERM LOOKING TO BE
FROM TONIGHT THROUGH TUESDAY EVENING. TEMPERATURES WILL REMAIN
SLIGHTLY BELOW AVERAGE THROUGH THE MIDDLE OF THE WEEK IN MOST
AREAS...WITH HIGHS IN THE 70S TO MID 80S.
FOR TODAY...DRY CONDITIONS ARE EXPECTED THROUGH THE MORNING
HOURS...WITH SOME SUNSHINE. CHANCE FOR STORMS WILL INCREASE THROUGH
THE AFTERNOON AND INTO TONIGHT AS ATMOSPHERE DESTABILIZES AND WEAK
ENERGY ALOFT APPROACHES BY THE EVENING. THE BLACK HILLS AND
NORTHEASTERN WY WILL GENERALLY SEE THE EARLIEST CHANCES FOR STORMS
THIS AFTERNOON AS FRONTAL BOUNDARY TRIES TO DRIFT EAST INTO
NORTHEASTERN WY AGAIN. ANOTHER AREA THAT COULD SEE A FEW
THUNDERSTORMS EARLIER IN THE AFTERNOON IS TOWARD CENTRAL SD...WHERE
SOME HI RES MODELS ARE SHOWING ACTIVITY DEVELOPING BY MID AFTERNOON.
WEAK LOW LEVEL UPSLOPE FLOW WILL PERSIST OVER MUCH OF THE
AREA...WITH PLENTY OF MOISTURE AND INSTABILITY PROGGED FOR THE BLACK
HILLS AREA EASTWARD THIS AFTERNOON. STEEPER MID LEVEL LAPSE RATES
ARE ALSO PROGGED LATER TODAY...HELPING TO WEAKEN THE CAP. SHEAR
WILL BE SLOWLY INCREASING THROUGH THE AFTERNOON AND INTO TONIGHT AND
SHOULD BE SUFFICIENT FOR A SUPERCELL OR TWO TO POTENTIALLY DEVELOP.
UPPER LEVEL SUPPORT LOOKS RATHER MINIMAL THROUGH THE AFTERNOON...SO
THIS WILL LIKELY KEEP ACTIVITY ISOLATED TO WIDELY SCATTERED THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING IN MOST AREAS. A FEW STRONG
TO SEVERE STORMS ARE POSSIBLE LATER THIS AFTERNOON AND TONIGHT.
LARGE HAIL AND STRONG WIND GUSTS WILL BE THE MAIN THREATS WITH ANY
SEVERE STORMS. AS WEAK ENERGY ALOFT CROSSES TONIGHT AND LOW LEVEL
JET INTENSIFIES OVER THE AREA THIS EVENING...THE COVERAGE OF STORMS
COULD EXPAND SOME INTO THE OVERNIGHT HOURS...ESPECIALLY EAST OF THE
BLACK HILLS.
TUESDAY LOOKS TO BE A SIMILAR SETUP AGAIN...THOUGH CHANCES FOR
STORMS LOOK TO PERSIST ALL DAY AND INTO TUESDAY NIGHT. ACTIVITY
COULD BE A BIT MORE WIDESPREAD AND CONCENTRATED MORE TO THE BLACK
HILLS AND THE PLAINS TO THE SOUTH AND EAST. ISOLATED STRONG TO
SEVERE STORMS AGAIN LOOK LIKELY...MAINLY FOR THE AFTERNOON AND
EVENING HOURS.
&&
.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 308 AM MDT MON AUG 12 2013
A GRADUAL CHANGE IN THE PATTERN IS EXPECTED THIS WEDNESDAY
THROUGH SATURDAY. ON WEDNESDAY THERE WILL BE YET ANOTHER SHORT-
WAVE TROUGH TRAVERSING THE RIDGE OVER THE CNTRL ROCKIES...AND THIS
SHOULD BRING A ROUND OF SHRA/TSRA TO THE CWA. THE FINAL SHORT-
WAVE TROUGH SHOULD MOVE SOUTHEAST THROUGH THE CWA ON THURSDAY.
THIS WILL BE FOLLOWED BY A SLOW EASTWARD PROGRESSION OF THE
RIDGE...BUT ALSO BUILDING UPPER HEIGHTS. THE NET RESULT SHOULD BE
A RELATIVE DRYING AND WARMING TREND OVER THE CURRENT/RECENT
PERSISTENT COOL AND MOIST PATTERN. NEVERTHELESS...TEMPS SHOULD BE
TEMPERED SOMEWHAT BY THE MOIST/GREEN GROUND AND THUS MAX TEMPS
HAVE BEEN TRIMMED BY 2-5 DEGREES. BY NEXT SUNDAY IT APPEARS A
SHORT-WAVE TROUGH WILL BREAK DOWN THE RIDGE AND MOVE ACROSS THE
NRN PLAINS. THIS COULD PRODUCE A FEW SEVERE STORMS...BUT IT ALSO
MAY RESULT IN A CRITICAL FIRE WEATHER PATTERN. HOWEVER...THE
RELATIVELY MOIST FUELS LIKELY WILL TEMPER THE EFFECTS OF THIS
PATTERN. THE RIDGE IS THEN PROGGED TO REBOUND ON MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1135 AM MDT MON AUG 12 2013
IFR/LIFR CIGS/VSBYS OVER PORTIONS OF WCNTRL SD /INCLUDING KRAP/
ARE BEGINNING TO ERODE AS FILTERED SUN WORKS ON THE BL. DID
RETAIN A LINGERING LIFR MENTION THERE INTO THE EARLY AFTERNOON.
OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE PERIOD
SAVE IN AN NEAR SCT TS THIS AFTERNOON AND TONIGHT. MVFR/IFR CIGS
WILL BE POSSIBLE ONCE AGAIN TOWARD DAWN OVER THE EASTERN FA...WITH
EASTERLY FLOW POSSIBLY PUSHING STRATUS BACK INTO THE EASTERN BH
FOOTHILLS TUE MORNING. DID HINT AT THIS IN THE RAP TAF.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...26
LONG TERM...BUNKERS
AVIATION...JC
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
941 PM CDT TUE AUG 13 2013
.UPDATE...
SEE DISCUSSION FOR EVENING UPDATE.
&&
.DISCUSSION...
SHOWERS AND THUNDERSTORMS ACROSS THE CWA BORDER HAVE HAD TROUBLE
MOVING SOUTHWARDS THIS EVENING. THIS ACTIVITY IS IN RESPONSE TO A
WEAK FRONTAL BOUNDARY THAT IS SAGGING SOUTHWARDS. RAIN LOOKS TO
START IN THE NORTHEASTERN COUNTIES EARLY THIS MORNING THEN SLOWLY
SPREAD TOWARDS THE SOUTH WITH THE BOUNDARY DURING THE DAY. THE
CHANCE OF RAIN OVERNIGHT DOES LOOK TO BE IN QUESTION AS DRY MID-
LEVEL AIR REMAINS IN PLACE (ESPECIALLY FURTHER TOWARDS THE
SOUTH). THIS CAN BE SEEN IN THE 0Z SOUNDING FROM KCRP THAT REVEALS
A PWAT OF ONLY 1.50". THE KFWD SOUNDING ON THE OTHER HAND HAS A
PWAT VALUE OF OVER 2.00". MODELS ARE FORECASTING FOR THE DRY AIR
TO BE PUSHED SOUTHWARDS TOMORROW BUT THE EXACT TIMING OF THIS WILL
BE TOUGH TO PREDICT. LIFT TOMORROW WILL COME FROM THE DIFFUSE
BOUNDARY WHICH SHOULD MAKE IT TO JUST NORTH OF INTERSTATE 10.
CONVECTIVE OUTFLOWS WILL THEN PUSH SOUTHWARDS LATER IN THE DAY
AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. THERE SHOULD BE
ENOUGH DAYTIME HEATING TO ALLOW FOR CONVECTIVE TEMPERATURES TO BE
REACHED. THE SOUTHWESTERN ZONES WILL BE THE LAST TO SEE THE RAIN
AND COVERAGE SHOULD BE LESS DUE TO THE LOWER MOISTURE AND WEAKER
LAPSE RATES. UPPER LEVEL SUPPORT ALSO APPEARS TO BE MORE OFF
TOWARDS THE EAST TOMORROW. GIVEN THESE TRENDS HAVE PULLED POPS
BACK SLIGHTLY. NEW ZONES WILL BE OUT SHORTLY. 23
&&
.PREV DISCUSSION... /ISSUED 814 PM CDT TUE AUG 13 2013/
AVIATION...
STORMS ALONG AND SOUTH OF A VERY DIFFUSE FRONTAL BOUNDARY HAVE
BEEN WANING QUICKLY. SOME HIGH CLOUDS WILL DRIFT SOUTHEAST INTO
THE AREA OVERNIGHT. VFR CONDITIONS SHOULD PREVAIL OVERNIGHT WITH
SOME SHOWERS AND POSSIBLY A THUNDERSTORM NORTHEAST OF THE UTS
TERMINAL. TOMORROW IS NOT SO STRAIGHT FORWARD...THE DIFFUSE FRONT
CONTINUES TO SAG SOUTHWARD AS UPPER LEVEL RIDGING (CAPPING) OVER
CENTRAL AND SOUTHERN TX SLIDES SLOWLY WEST AND TROUGHING DIPS
DOWN INTO LA. RICH MOISTURE AND COOLING TEMPERATURES ALOFT IN
COMBINATION WITH A LL FOCUS POINTS TOWARDS THE DEVELOPMENT OF
SHRA/TSRA BUT MODELS ARE IN DISAGREEMENT WITH RESPECT TO TIMING
AND LOCATION BETWEEN 12Z AND 03Z/14 AND IN SOME CASES WIDELY. NOT
THAT CONFIDENT CONVECTION WILL BE WIDESPREAD IN THE NORTH IN THE
MORNING BUT AS HEATING INCREASES EXPECT THAT AT LEAST SCATTERED
SHRA/TSRA SHOULD DEVELOP. EVENTUALLY OUTFLOW SPREADS SOUTH AND
SHOULD REACH THE METRO TERMINALS MID TO LATE AFTERNOON SO PEAK IN
ACTIVITY WILL PROBABLY BE IN THE AFTERNOON FOR THE HOUSTON AREA
TERMINALS. STORMS SHOULD WANE AGAIN TOMORROW EVENING ESPECIALLY IN
THE SOUTHWEST WHERE STRONGER CAP WILL STILL BE IN PLACE. 45
PREV DISCUSSION... /ISSUED 346 PM CDT TUE AUG 13 2013/
DISCUSSION...
MUCH CONVECTIVE ACTIVITY OCCURRING ALONG A NORTHERN TEXAS (QUASI)
STATIONARY BOUNDARY THAT MAY EVENTUAL IMPACT OUR NORTH(EAST)ERN
COUNTIES WITHIN THE NEXT 4 TO 6 HOURS. A VERY HEATED AND MOIST
DOWNSTREAM AIR MASS FOR THIS STATIONARY BOUNDARY...OR SUBSEQUENT
CONVECTIVE OUTFLOW...TO WORK WITH IN THE COMING 24-36 HOURS.
THERE IS STILL SUBSIDENCE TO WORK WITH AS THERE HAVE BEEN RECENT
HEIGHT RISES AND A FEW DEGREES OF WARMTH AT THE 85-7H LEVELS...BUT
THE UPPER LEVELS REMAIN FAIRLY DIFFLUENT AS EAST TEXAS FALLS
WITHIN A (RELATIVELY) MILD MID-UPPER LEVEL HEIGHT WEAKNESS BETWEEN
DESERT SOUTHWEST AND FLORIDA-CENTERED RIDGING.
ALL OF THE THERMODYNAMIC INDICES ARE THERE TO SUPPORT RETURNING
SCATTERED SHOWERS AND STORMS BEGINNING AS EARLY AS MID-WEDNESDAY
MORNING. K-INDICES AROUND 40...L.I. IN THE -5 REALM...AND ABOVE
1 K J/KG CAPES FROM THE GFS/NAM PROGS OVER THE NORTHERN CWA
INCREASE THE SHOWER/STORM PROBABILITY. YES...THERE WILL BE SOME
SUBSIDENCE TO DEAL WITH...BUT WITH A CONSISTENT RUN-TO-RUN THEME
OF INTRODUCING WEAK LOWER MS VALLEY TROUGHING (AND WITNESSING WHAT
IS ONGOING ACROSS DFW`S FA)...HAD TO BITE ON THE LIKELY SIDE OF
POPS. GREATER THAN 2 INCH PWATS WILL POOL ALONG `A` BOUNDARY...WHETHER
THAT BE MORE OF A SYNOPTIC OR A SERIES OF MESOSCALE (UPSTREAM
OUTFLOW) BOUNDARIES. OTHER THAN SUBSIDENCE AS A RAIN INHIBITER...THE
ONLY OTHER NEGATIVE TO MORE WIDESPREAD COVERAGE WOULD BE THAT THE
REGION DOES FALL INTO MORE OF A RR QUAD OF THE JET (ALTHOUGH 25-3H
FLOW REMAINS DIFFLUENT).
NEEDLESS TO SAY...BUT WHAT EVOLVES TOMORROW WILL DRIVE THURSDAY`S
FORECAST. SINCE THE FORECAST IS MORE WET TOMORROW...ANTICIPATING
THAT THERE WILL BE SOME RESIDUAL BOUNDARIES LEFT OVER IN THE MIX.
A LESS-WORKED OVER SOUTHERN CWA AIR MASS...WITH POSSIBLE LEFT-OVER
WEDNESDAY SMALL SCALE BOUNDARIES (AND MAYBE SOME ASSISTANCE FROM
THE LOCAL BREEZE?) WILL KEEP CHANCE POPS IN PLAY CLOSER TO THE
COAST THURSDAY INTO FRIDAY. A MUCH DRIER AIR MASS FILTERING IN
ALONG THE WESTERN LEG OF A EASTERN-BASED MID-UPPER TROUGH AXIS
WILL COME OVER US DURING THE WEEKEND...SUBSTANTIALLY LOWERING
RAIN CHANCES.
THE EXTENDED SHOWS NOT MUCH IN THE WAY OF ANY DISCERNIBLE WEATHER
FEATURE THAT WILL INCREASE RAIN CHANCES BEYOND THE LOCAL SCALE
BREEZES. IF ANYTHING...RIDGING TAKES MORE OF A GRIP AND MID-LEVELS
ARE MODELED TO WARM BACK UP INTO THE LOWER 20S BY THIS TIME NEXT
WEEK. AS HAS BEEN THE CASE THESE PAST FEW DAYS...THE BAY OF CAMPECHE
HAS REMAINED SOMEWHAT ACTIVE...WITH THE NWP SUITE MAINTAINING
LOWERING PRESSURES AND A GREATER THAN 2 INCH PW AIR MASS. CENTRAL
GULF SHEAR REMAINS STOUT (30 KTS BETWEEN THE TWO UPPER RIDGES) SO
NOT TOO WORRIED WITH ANY CLOSED-OFF CIRCULATION MOVING TOO FAR
NORTH OF THE BAY. 31
MARINE...
A RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP MAINLY LIGHT ONSHORE WINDS AND LOW SEAS IN PLACE THROUGH THE
MIDDLE OF THE WEEK. A WEAK FRONT IS STILL EXPECTED TO APPROACH THE
COAST FROM THE NORTH AND NORTHEAST ON WEDNESDAY NIGHT AND THURSDAY.
THIS BOUNDARY COULD BRING THE AREA A BRIEF PERIOD OF OFFSHORE WINDS.
A WEAK TROUGH OF LOW PRESSURE OVER THE CENTRAL GULF WILL MAINTAIN E-NE
WINDS THROUGH SUNDAY. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 76 95 73 95 75 / 20 40 20 20 10
HOUSTON (IAH) 78 96 76 93 74 / 20 30 30 40 20
GALVESTON (GLS) 83 91 81 90 81 / 10 20 40 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...23
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
814 PM CDT TUE AUG 13 2013
.AVIATION...
STORMS ALONG AND SOUTH OF A VERY DIFFUSE FRONTAL BOUNDARY HAVE
BEEN WANING QUICKLY. SOME HIGH CLOUDS WILL DRIFT SOUTHEAST INTO
THE AREA OVERNIGHT. VFR CONDITIONS SHOULD PREVAIL OVERNIGHT WITH
SOME SHOWERS AND POSSIBLY A THUNDERSTORM NORTHEAST OF THE UTS
TERMINAL. TOMORROW IS NOT SO STRAIGHT FORWARD...THE DIFFUSE FRONT
CONTINUES TO SAG SOUTHWARD AS UPPER LEVEL RIDGING (CAPPING) OVER
CENTRAL AND SOUTHERN TX SLIDES SLOWLY WEST AND TROUGHING DIPS
DOWN INTO LA. RICH MOISTURE AND COOLING TEMPERATURES ALOFT IN
COMBINATION WITH A LL FOCUS POINTS TOWARDS THE DEVELOPMENT OF
SHRA/TSRA BUT MODELS ARE IN DISAGREEMENT WITH RESPECT TO TIMING
AND LOCATION BETWEEN 12Z AND 03Z/14 AND IN SOME CASES WIDELY. NOT
THAT CONFIDENT CONVECTION WILL BE WIDESPREAD IN THE NORTH IN THE
MORNING BUT AS HEATING INCREASES EXPECT THAT AT LEAST SCATTERED
SHRA/TSRA SHOULD DEVELOP. EVENTUALLY OUTFLOW SPREADS SOUTH AND
SHOULD REACH THE METRO TERMINALS MID TO LATE AFTERNOON SO PEAK IN
ACTIVITY WILL PROBABLY BE IN THE AFTERNOON FOR THE HOUSTON AREA
TERMINALS. STORMS SHOULD WANE AGAIN TOMORROW EVENING ESPECIALLY IN
THE SOUTHWEST WHERE STRONGER CAP WILL STILL BE IN PLACE. 45
&&
.PREV DISCUSSION... /ISSUED 346 PM CDT TUE AUG 13 2013/
DISCUSSION...
MUCH CONVECTIVE ACTIVITY OCCURRING ALONG A NORTHERN TEXAS (QUASI)
STATIONARY BOUNDARY THAT MAY EVENTUAL IMPACT OUR NORTH(EAST)ERN
COUNTIES WITHIN THE NEXT 4 TO 6 HOURS. A VERY HEATED AND MOIST
DOWNSTREAM AIR MASS FOR THIS STATIONARY BOUNDARY...OR SUBSEQUENT
CONVECTIVE OUTFLOW...TO WORK WITH IN THE COMING 24-36 HOURS.
THERE IS STILL SUBSIDENCE TO WORK WITH AS THERE HAVE BEEN RECENT
HEIGHT RISES AND A FEW DEGREES OF WARMTH AT THE 85-7H LEVELS...BUT
THE UPPER LEVELS REMAIN FAIRLY DIFFLUENT AS EAST TEXAS FALLS
WITHIN A (RELATIVELY) MILD MID-UPPER LEVEL HEIGHT WEAKNESS BETWEEN
DESERT SOUTHWEST AND FLORIDA-CENTERED RIDGING.
ALL OF THE THERMODYNAMIC INDICES ARE THERE TO SUPPORT RETURNING
SCATTERED SHOWERS AND STORMS BEGINNING AS EARLY AS MID-WEDNESDAY
MORNING. K-INDICES AROUND 40...L.I. IN THE -5 REALM...AND ABOVE
1 K J/KG CAPES FROM THE GFS/NAM PROGS OVER THE NORTHERN CWA
INCREASE THE SHOWER/STORM PROBABILITY. YES...THERE WILL BE SOME
SUBSIDENCE TO DEAL WITH...BUT WITH A CONSISTENT RUN-TO-RUN THEME
OF INTRODUCING WEAK LOWER MS VALLEY TROUGHING (AND WITNESSING WHAT
IS ONGOING ACROSS DFW`S FA)...HAD TO BITE ON THE LIKELY SIDE OF
POPS. GREATER THAN 2 INCH PWATS WILL POOL ALONG `A` BOUNDARY...WHETHER
THAT BE MORE OF A SYNOPTIC OR A SERIES OF MESOSCALE (UPSTREAM
OUTFLOW) BOUNDARIES. OTHER THAN SUBSIDENCE AS A RAIN INHIBITER...THE
ONLY OTHER NEGATIVE TO MORE WIDESPREAD COVERAGE WOULD BE THAT THE
REGION DOES FALL INTO MORE OF A RR QUAD OF THE JET (ALTHOUGH 25-3H
FLOW REMAINS DIFFLUENT).
NEEDLESS TO SAY...BUT WHAT EVOLVES TOMORROW WILL DRIVE THURSDAY`S
FORECAST. SINCE THE FORECAST IS MORE WET TOMORROW...ANTICIPATING
THAT THERE WILL BE SOME RESIDUAL BOUNDARIES LEFT OVER IN THE MIX.
A LESS-WORKED OVER SOUTHERN CWA AIR MASS...WITH POSSIBLE LEFT-OVER
WEDNESDAY SMALL SCALE BOUNDARIES (AND MAYBE SOME ASSISTANCE FROM
THE LOCAL BREEZE?) WILL KEEP CHANCE POPS IN PLAY CLOSER TO THE
COAST THURSDAY INTO FRIDAY. A MUCH DRIER AIR MASS FILTERING IN
ALONG THE WESTERN LEG OF A EASTERN-BASED MID-UPPER TROUGH AXIS
WILL COME OVER US DURING THE WEEKEND...SUBSTANTIALLY LOWERING
RAIN CHANCES.
THE EXTENDED SHOWS NOT MUCH IN THE WAY OF ANY DISCERNIBLE WEATHER
FEATURE THAT WILL INCREASE RAIN CHANCES BEYOND THE LOCAL SCALE
BREEZES. IF ANYTHING...RIDGING TAKES MORE OF A GRIP AND MID-LEVELS
ARE MODELED TO WARM BACK UP INTO THE LOWER 20S BY THIS TIME NEXT
WEEK. AS HAS BEEN THE CASE THESE PAST FEW DAYS...THE BAY OF CAMPECHE
HAS REMAINED SOMEWHAT ACTIVE...WITH THE NWP SUITE MAINTAINING
LOWERING PRESSURES AND A GREATER THAN 2 INCH PW AIR MASS. CENTRAL
GULF SHEAR REMAINS STOUT (30 KTS BETWEEN THE TWO UPPER RIDGES) SO
NOT TOO WORRIED WITH ANY CLOSED-OFF CIRCULATION MOVING TOO FAR
NORTH OF THE BAY. 31
MARINE...
A RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP MAINLY LIGHT ONSHORE WINDS AND LOW SEAS IN PLACE THROUGH THE
MIDDLE OF THE WEEK. A WEAK FRONT IS STILL EXPECTED TO APPROACH THE
COAST FROM THE NORTH AND NORTHEAST ON WEDNESDAY NIGHT AND THURSDAY.
THIS BOUNDARY COULD BRING THE AREA A BRIEF PERIOD OF OFFSHORE WINDS.
A WEAK TROUGH OF LOW PRESSURE OVER THE CENTRAL GULF WILL MAINTAIN E-NE
WINDS THROUGH SUNDAY. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 76 94 73 95 75 / 20 60 20 20 10
HOUSTON (IAH) 78 96 76 93 74 / 20 60 30 40 20
GALVESTON (GLS) 83 91 81 90 81 / 10 40 40 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...23
AVIATION/MARINE...45
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
346 PM CDT MON AUG 12 2013
.SHORT TERM...
WEATHER PATTERN OVER THE NEXT DAY WILL BE LARGELY DRIVEN BY
ELONGATED UPPER HIGH ALONG THE GULF COAST WITH A RIDGE EXTENDING
FROM AROUND THESE PARTS UP TO THE CANADIAN PRAIRIES. MONSOON
MOISTURE CONTINUES TO WRAP AROUND THE PERIPHERY OF THE HIGH CENTER
GENERALLY STREAMING FROM NORTHEASTERN NEW MEXICO TO THE TEXAS
PANHANDLE AND BEYOND. AREA OF SYNOPTIC SCALE LIFT IS EVIDENT TO OUR
NORTH AND NORTHWEST AND THIS IS WHERE TSTM ACTIVITY INITIATED.
HOWEVER...TO THE SOUTH...ACROSS OUR REGION...AXIS OF THETA-E MAXIMA
HAS HELPED INITIATE ISOLATED CONVECTION FROM DORA TO MEMPHIS. GIVEN
THAT THESE SHOWERS DEVELOPED BY 2PM...INDICATIONS ARE THAT THE
ATMOSPHERE IS SUFFICIENTLY MOIST TO SUPPORT AT LEAST SCATTERED STORMS
FOR MUCH OF THE AFTERNOON INTO THE EVENING HOURS...FAVORING THE
NORTHERN HALF OF THE AREA. AN INTERESTING SOLUTION IS EVIDENT IN
THE HRRR WITH CONVECTION FORMING OUT NORTHWEST OF LUBBOCK AND MOVING
SLOWLY THIS WAY...BUT PERHAPS NOT REACHING THE CITY. GIVEN THAT
THIS SOLUTION IS SOMEWHAT REPRESENTED IN LOCATION / THOUGH NOT
COVERAGE / HAVE EXPANDED POPS SOUTHWARD THIS EVENING. LIKE THE PAST
SEVERAL NIGHTS...LOW-END SEVERE STORMS WILL BE POSSIBLE WITH
CONDITIONS WANING TUESDAY MORNING FOR A WHILE. A BACK DOOR FRONT
IS INDICATED BY GUIDANCE AND WITH THE ALREADY PLENTIFUL CONVECTION
ACROSS THE PANHANDLE...PREFER THE QUICKER SOLUTION AND AS SUCH
HAVE BROUGHT THE BOUNDARY...AND ASSOCIATED INCREASED RAIN
CHANCES...INTO OUR CWFA DURING THE AFTERNOON ON TUESDAY.
&&
.LONG TERM...
MID-LEVEL PATTERN WILL CONTINUE TO AMPLIFY INTO THE EXTENDED WITH
STRONGER NW FLOW AND DEEP LAYER SHEAR ACROSS THE SOUTH PLAINS TUE
PM INTO WED IN THE WAKE OF THE FRONTAL BOUNDARY. THIS SCENARIO
SHOULD SUPPORT CONTINUED WIDESPREAD PRECIP CHANCES AS MOST MODELS
SUPPORT SOME Q-G LIFT ALONG WITH FRONTOGENETICAL FORCING CENTERED
OVER ERN NM INTO THE WRN SOUTH PLAINS. FAVORABLE 700MB THETA-E AXIS ALSO
REMAINS IN PLACE WITH PWATS INCREASING THROUGH THE FIRST COUPLE OF
DAYS OF THE EXTENDED PERIOD AS WELL. ONE LIMITING FACTOR FOR
CONSIDERATION FOR INCREASED COVERAGE WITH TIME IS THE INSTABILITY
DURING THE DAY WED. EXPECT CONSIDERABLE CLOUDINESS AND UPSLOPE
FLOW TO INHIBIT WARMING AND SUBSTANTIAL CAPE HOWEVER DEEPLY MOIST
ATMOSPHERE SHOULD AID DEVELOPMENT LOCALLY. ADDITIONAL HEATING
ACROSS EASTERN NM COUPLED WITH AMPLE SHEAR SHOULD HELP SOME
ACTIVITY TO ORGANIZE AND MOVE ACROSS THE WESTERN HALF OF THE AREA
AGAIN LATE EVENING AND OVERNIGHT WED NIGHT. SUBTLE SHORTWV
ACTIVITY TRAVERSING THE NW FLOW WILL HELP SUSTAIN AFTN STORMS THU
IN CONTINUED LIGHT UPSLOPE FLOW. ONCE AGAIN UNCAPPED ATMOSPHERE WILL
ALLOW SHOWERS TO FORM EARLY AND PREVENT THINGS FROM BECOMING TOO
UNSTABLE WITH SEVERE THREAT LIMITED OUTSIDE OF SOME HEAVY RAINERS.
FLOW TURNS MORE NRLY ON FRI AS RIDGE BUILDS FROM 4 CORNERS INTO
MONTANA. GFS AND EURO BOTH SUPPORT UPPER LOW DROPPING INTO THE MO
VALLEY ON SAT TO MAINTAIN SOME LIFT WITHIN REMNANT MOIST AXIS ON
EASTERN SIDE OF THE RIDGE. WITH CONTINUED ISOLD-SCT CONVECTION
POSSIBLE HAVE KEPT POPS GOING INTO THE WEEKEND WITH LITTLE TO NO
OVERALL WARMING TREND.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 89 65 81 61 / 30 30 50 50 40
TULIA 65 89 67 80 62 / 30 30 50 50 40
PLAINVIEW 66 91 68 80 63 / 30 30 40 50 40
LEVELLAND 70 94 68 84 65 / 20 20 30 50 40
LUBBOCK 70 93 69 83 65 / 20 20 30 50 40
DENVER CITY 72 92 65 88 66 / 10 10 20 40 40
BROWNFIELD 73 94 70 86 66 / 10 10 20 50 40
CHILDRESS 72 96 69 84 67 / 30 40 50 50 30
SPUR 75 97 74 86 68 / 20 20 30 50 40
ASPERMONT 76 99 75 89 69 / 20 20 30 50 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
26/24
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1229 PM CDT MON AUG 12 2013
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE METROPLEX AND WACO
TAF SITES THROUGH 00Z WEDNESDAY. ISOLATED THUNDERSTORMS ARE
EXPECTED LATE AFTERNOON INTO THIS EVENING /21Z-03Z/ NORTH OF THE
DALLAS FORT WORTH METROPLEX AS AN UPEPR LEVEL DISTURBANCE SLIDES
ACROSS OKLAHOMA. ISOLATED SHOWERS AND THUNDERSTORMS ARE ALSO
POSSIBLE LATE AFTERNOON THROUGH EARLY EVENING /21Z-01Z/ SOUTH OF
WACO. ALTHOUGH IT IS NOT MENTIONED IN THE DFW TAF AT THIS
TIME...THERE MAY BE SOME ISOLATED THUNDERSTORMS NORTH OF I-20
AFTER 20Z TUESDAY.
58
&&
.UPDATE...
THE NAM12 HAS DONE A GOOD JOB WITH THE CURRENT ACTIVITY OVER NE
OKLAHOMA THIS MORNING ASSOCIATED WITH AN EAST-SOUTHEASTWARD MOVING
SHORTWAVE. THIS MODEL ALONG WITH RECENT RUNS OF THE HRRR HAVE
ADVERTISED ISOLATED THUNDERSTORM DEVELOPMENT FARTHER SOUTHWEST THIS
AFTERNOON INTO NORTHERN PORTIONS OF THE CWA. WILL GO AHEAD AND ADD
ISOLATED TS TO THE COUNTIES NORTH OF THE DALLAS-FORT WORTH
METROPLEX FOR THE AFTERNOON WITH TIMING MOST LIKELY AFTER 4
PM...WHILE CONTINUING WITH ISOLATED TS OVER THE FAR SOUTHERN
COUNTIES AS WELL. OTHERWISE THE FORECAST REMAINS IN GOOD SHAPE
WITH MOST AREAS REACHING UPPER 90S TO NEAR 100 DEGREE HIGH TEMPS
AGAIN TODAY.
30
&&
.PREV DISCUSSION... /ISSUED 424 AM CDT MON AUG 12 2013/
REGIONAL RADARS WERE SHOWING A FEW CLUSTERS OF SHOWERS AND
THUNDERSTORMS MOVING EAST-NORTHEAST FROM APPROXIMATELY PLAINVIEW
TX TO LAWTON OK. THIS AREA OF PRECIPITATION WAS MASKING THE
POSITION OF THE NORTHWARD MOVING BOUNDARY THAT WAS IN PLACE OVER
THE DFW METROPLEX YESTERDAY AFTERNOON. IT IS POSSIBLE THAT THE
BOUNDARY IS NEAR THE LINE OF SHOWER AND THUNDERSTORM ACTIVITY
MENTIONED ABOVE...BUT A CHAOTIC WIND AND TEMPERATURE FIELD DUE TO
MULTIPLE OUTFLOW BOUNDARIES MADE THE FRONT DIFFICULT TO LOCATE ON
A SURFACE SUBJECTIVE ANALYSIS AT 08Z. EARLY MORNING WATER VAPOR
SATELLITE IMAGERY SHOWED AN ANTICYCLONIC CIRCULATION CENTERED
NEAR EL PASO WITH WESTERLY FLOW ALOFT OVER KS AND OKLAHOMA.
FURTHER NORTH...A STRONG SHORTWAVE TROUGH WAS EVIDENT NORTH OF
MINNESOTA...MOVING SOUTHEAST TOWARDS THE UPPER GREAT LAKES REGION.
TODAY THROUGH TUESDAY...ASSUMING THE FRONT CONTINUES TO MOVE NORTH
THIS MORNING...THERE WILL BE NO OBVIOUS FOCUS FOR AFTERNOON
THUNDERSTORMS TODAY THROUGH EARLY TUESDAY AFTERNOON ACROSS NORTH
TX. IN GENERAL WITH PERSISTENT SOUTHERLY FLOW AND MOSTLY SUNNY
SKIES...WE SHOULD SEE HIGHS CONTINUE TO TOP OUT IN THE UPPER 90S
TO JUST ABOVE 100 DEGREES FOR MOST LOCATIONS MONDAY AND TUESDAY.
THERE IS SOME CONCERN THAT THE CLUSTER OF STORMS LOCATED FROM
PLAINVIEW TO LAWTON WILL BE ABLE TO SEND SOME SORT OF CONSOLIDATED
OUTFLOW BOUNDARY SOUTH TOWARDS THE RED RIVER THIS MORNING. THE
RADAR PRESENTATION OF THIS CONVECTION AT 08Z DID NOT SEEM VIGOROUS
ENOUGH TO SEND A BOUNDARY SOUTH TO THE RED RIVER...HOWEVER A FEW
EARLY MORNING RUNS OF THE RAP AND THE NCEP 4 KM WRF SEEM TO BE
ADVERTISING THIS SCENARIO FOR THUNDERSTORM CONSIDERATIONS LATER
THIS AFTERNOON...EVEN THE 06Z NAM APPEARS TO BE INDICATING A
SUBTLE BOUNDARY NEAR THE RED RIVER. HOWEVER...THE CONSENSUS OF
MOST MODEL GUIDANCE SENDS THE FRONT NORTH TO THE KS/OK BORDER
TODAY...WELL REMOVED FROM NORTH TX. WITH LITTLE CONFIDENCE THAT A
SIGNIFICANT BOUNDARY WILL MOVE TO THE RED RIVER OR INTO NORTH TX
THIS MORNING...LEFT 10 POPS IN THE FORECAST WITHOUT ANY MENTION OF
THUNDERSTORMS THROUGH THIS AFTERNOON.
WITH MOST MODEL GUIDANCE BRINGING THE FRONT NORTH TO THE KS/OK
BORDER THIS AFTERNOON...THIS SHOULD SERVE AS A NICE FOCUS FOR
AFTERNOON THUNDERSTORM INITIATION. THE MINNESOTA UPPER LEVEL
TROUGH IS EXPECTED TO DIVE SOUTHEAST TODAY WHICH MARKS THE
BEGINNING OF A LARGE SCALE TROUGH THAT WILL BUILD OVER THE ENTIRE
EASTERN CONUS BY LATE THIS WEEK. THIS FIRST STRONG SHORTWAVE
TROUGH WILL TURN THE WESTERLIES ALOFT OVER KS/OK SLIGHTLY TO THE
SOUTH...RESULTING IN WEST-NORTHWEST FLOW ALOFT BY THIS EVENING.
WITH STRONGER DEEP LAYER SHEAR TO WORK WITH ALONG THE KS/OK
BORDER...AND STEERING FLOW ALOFT TILTING TO THE SOUTH THIS
EVENING...IT IS POSSIBLE FOR SOME ORGANIZED MCS TO PULL AWAY FROM
THE FRONT AND MOVE SOUTH TOWARDS THE RED RIVER BEFORE MIDNIGHT
TONIGHT. OVERALL THINK THAT THE CHANCES OF THIS ARE
SMALL...HOWEVER DID GO WITH A SMALL AREA OF 20 POPS JUST SOUTH OF
THE RED RIVER TO ACCOUNT FOR THIS SCENARIO. MOST MODEL GUIDANCE
INDICATES VIGOROUS CONVECTION ALONG THE KS/OK BORDER BY THIS
AFTERNOON...SO WE WILL HAVE TO WATCH THE EVOLUTION OF ANY MCS FOR
SOME POTENTIAL TO MOVE INTO NORTH TX THIS EVENING OR OVERNIGHT.
DURING THE DAY ON TUESDAY THE CONTINUED SOUTHEASTWARD PUSH OF THE
MINNESOTA UPPER TROUGH WILL HELP TILT THE FLOW ALOFT MORE TO THE
NORTHWEST OVER THE SOUTH PLAINS AS UPPER LEVEL RIDGING REORGANIZES
OVER THE SOUTHWESTERN CONUS. ANOTHER STRONG SHORTWAVE TROUGH IS
EXPECTED TO MOVE SOUTHEAST OVER THE WESTERN GREAT LAKES TUESDAY
AFTERNOON WHICH SHOULD HELP SEND THE KS/OK COLD FRONT SOUTH INTO
NORTH TX BY TUESDAY NIGHT. ALL MODELS SHOW NUMEROUS SHOWERS AND
THUNDERSTORMS ALONG THE FRONT TUESDAY AFTERNOON AND EVENING. THIS
WILL LIKELY CAUSE THE FRONT TO MOVE TO THE SOUTH FASTER...SO
GENERALLY FAVORED MODELS WITH A QUICKER FRONTAL PASSAGE IN THIS
FORECAST.
HAVE THUNDERSTORM CHANCES INCREASING FROM AROUND 20 PERCENT NEAR
THE RED RIVER TUESDAY AFTERNOON TO 50 TO 60 PERCENT NEAR THE RED
RIVER TUESDAY EVENING. HAVE POPS IN THE FORECAST TUESDAY NIGHT AS
FAR SOUTH AS WACO...HOWEVER CONFIDENCE IN THUNDERSTORMS DIMINISHES
FROM NORTH TO SOUTH ACROSS THE CWA. THUNDERSTORMS ARE MOST LIKELY
ALONG AND NORTH OF INTERSTATE 20 TUESDAY EVENING AND OVERNIGHT.
THERE IS SOME CHANCE THAT THESE STORMS WILL BE SEVERE AS THEY MOVE
INTO NORTH TX TUESDAY NIGHT...HOWEVER SEVERE WEATHER POTENTIAL IS
EXPECTED TO BE LIMITED BY THE STORMS MOVING INTO THE AREA AFTER
SUNSET.
ANY SEVERE STORMS WOULD LIKELY BE IN THE FORM OF A SMALL LINEAR
MCS AS DEEP LAYER BULK SHEAR IS FORECAST TO BE 30 TO 35 KTS ALONG
AND NORTH OF INTERSTATE 20. SHEAR WEAKENS TO THE SOUTH...AND
STORMS ARE NOT AS LIKELY TO MOVE SOUTH OF INTERSTATE 20 UNTIL LATE
TUESDAY EVENING...SO SEVERE WEATHER CHANCES TO THE SOUTH OF I-20
LOOK FAIRLY SMALL AT THIS TIME. DAMAGING WINDS WOULD BE THE MOST
LIKELY SEVERE WEATHER HAZARD...WITH CLOUD TO GROUND LIGHTNING AND
LOCALLY HEAVY RAINFALL POSSIBLE WITH ANY STORM.
NOCTURNAL CONVECTION USUALLY WEAKENS SUBSTANTIALLY NEAR DAWN IN
THE ABSENCE OF UPPER LEVEL SUPPORT. THINK THAT SHOWERS AND STORMS
ALONG THE FRONT WILL TEND TO WEAKEN EARLY WEDNESDAY MORNING
LEAVING SOME UNORGANIZED SHOWER AND THUNDERSTORM ACTIVITY NEAR THE
FRONT AS IT STALLS OUT WEDNESDAY MORNING. THE FRONT WILL MOST
LIKELY BE LOCATED JUST SOUTH OF INTERSTATE 20 AT THAT
TIME. ASSUMING THE FRONT STALLS OUT IN THIS LULL OF CONVECTIVE
ACTIVITY...THE STALLED OUT FRONT SHOULD SERVE AS A FOCUS FOR
THUNDERSTORM INITIATION WEDNESDAY AFTERNOON. WENT AHEAD AND PLACED
50 POPS ALONG THE EXPECTED POSITION OF THE FRONT...ROUGHLY IN
BETWEEN DFW AND WACO WITH LOWER POPS TO THE NORTH AND SOUTH DURING
THE DAY ON WEDNESDAY.
ADDITIONAL THUNDERSTORM ACTIVITY ALONG THE FRONT WEDNESDAY
AFTERNOON SHOULD SEND THE FRONT SOUTH OUT OF THE CWA BY WEDNESDAY
EVENING. AS A RESULT WENT AHEAD AND MOVED THE BEST POPS SOUTH FROM
WEDNESDAY AFTERNOON THROUGH THE OVERNIGHT HOURS. BY THURSDAY
MORNING...THE FRONT IS EXPECTED TO BE LOCATED JUST SOUTH OR
SOUTHWEST OF THE CWA.
THURSDAY...ASSUMING THE FRONT IS NOT IN THE CWA...CONFIDENCE IN
WHEN AND WHERE STORMS WILL DEVELOP ACROSS THE AREA IS SOMEWHAT
LOW. THE GFS CONTINUES TO INDICATE A SHORTWAVE TROUGH MOVING
TOWARDS THE CWA THURSDAY AFTERNOON OR EVENING WHICH COULD
CERTAINLY CAUSE ISOLATED STORMS TO DEVELOP WHEREVER THE GREATEST
LIFT OCCURS. KEPT POPS IN THE 20 TO 30 PERCENT RANGE AT THIS TIME
BECAUSE THE BEST MOISTURE AND INSTABILITY FOR STORMS IS EXPECTED
TO REMAIN SOUTH OF THE FRONT. WITH THE FRONTAL POSITION AT LEAST
SOMEWHAT DEPENDENT ON THE COVERAGE AND INTENSITY OF STORMS EACH
DAY...THIS FORECAST COULD CHANGE SIGNIFICANTLY DEPENDING ON WHERE
THE FRONT ACTUALLY IS AT THIS TIME. HOWEVER FOR NOW MOST GUIDANCE
KEEPS THE FRONT SOUTH OF THE CWA WHICH SHOULD DAMPEN THUNDERSTORM
CHANCES IN GENERAL.
RAIN COOLED AIR ON WEDNESDAY...AND COLD AIR ADVECTION BEHIND THE
COLD FRONT SHOULD KEEP TEMPERATURES BELOW NORMAL FROM WEDNESDAY
THROUGH THE END OF THE WEEK. THIS SHOULD PROVIDE SOME NICE RELIEF
FROM THE PREVIOUS TWO WEEKS OF 100 DEGREE HEAT. HIGHS WILL
GENERALLY BE HELD INTO THE MID TO UPPER 80S NORTH OF INTERSTATE 20
WITH HIGHS IN THE LOWER 90S TO THE SOUTH.
FRIDAY THROUGH MONDAY...THE GFS AND ECMWF BOTH INDICATE A STRONGER
SHORTWAVE TROUGH WILL BUILD OVER THE REGION BY FRIDAY BRINGING IN
AN UNUSUAL UPPER AIR PATTERN DOMINATED BY NORTHERLY FLOW ALOFT
OVER THE REGION THROUGH THE WEEKEND. IN GENERAL THIS PATTERN
FAVORS COOLER THAN NORMAL TEMPERATURES WITH LOW RAIN CHANCES DUE
TO DRIER CONTINENTAL AIR BEING ADVECTED INTO THE REGION. THE
FORECAST REFLECTS THESE GENERAL GUIDELINES. MAY HAVE TO INCLUDE
SOME POPS IN THE FORECAST AT A LATER DATE AS SMALLER SCALE
FEATURES BECOME BETTER RESOLVED...HOWEVER NO WIDESPREAD
PRECIPITATION IS EXPECTED AT THIS TIME. TEMPERATURES SHOULD RETURN
TO SEASONAL NORMALS BY MONDAY.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 100 80 99 78 90 / 10 10 10 30 50
WACO, TX 98 77 99 78 94 / 10 5 10 20 40
PARIS, TX 96 75 95 73 83 / 10 20 20 60 40
DENTON, TX 99 77 98 75 88 / 10 10 10 40 40
MCKINNEY, TX 99 78 99 76 87 / 10 10 20 40 50
DALLAS, TX 101 82 101 81 90 / 10 10 10 30 50
TERRELL, TX 100 78 99 77 89 / 10 10 10 30 50
CORSICANA, TX 100 78 100 78 94 / 10 10 10 20 50
TEMPLE, TX 96 74 98 75 94 / 10 10 10 10 30
MINERAL WELLS, TX 99 77 98 76 88 / 10 10 10 30 50
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/30
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1022 AM CDT MON AUG 12 2013
.UPDATE...
THE NAM12 HAS DONE A GOOD JOB WITH THE CURRENT ACTIVITY OVER NE
OKLAHOMA THIS MORNING ASSOCIATED WITH AN EAST-SOUTHEASTWARD MOVING
SHORTWAVE. THIS MODEL ALONG WITH RECENT RUNS OF THE HRRR HAVE
ADVERTISED ISOLATED THUNDERSTORM DEVELOPMENT FARTHER SOUTHWEST THIS
AFTERNOON INTO NORTHERN PORTIONS OF THE CWA. WILL GO AHEAD AND ADD
ISOLATED TS TO THE COUNTIES NORTH OF THE DALLAS-FORT WORTH
METROPLEX FOR THE AFTERNOON WITH TIMING MOST LIKELY AFTER 4
PM...WHILE CONTINUING WITH ISOLATED TS OVER THE FAR SOUTHERN
COUNTIES AS WELL. OTHERWISE THE FORECAST REMAINS IN GOOD SHAPE
WITH MOST AREAS REACHING UPPER 90S TO NEAR 100 DEGREE HIGH TEMPS
AGAIN TODAY.
30
&&
.AVIATION...
NO MAJOR CONCERNS THIS CYCLE. MOSTLY CLEAR SKIES EXPECTED WITH
SOUTHERLY FLOW OF 8-12 KTS EXPECTED NEXT 24-30 HOURS.
CONVECTION THIS AFTERNOON OR EVENING ACROSS TEXAS IS EXPECTED TO
BE WELL-REMOVED FROM THE TAF SITES. ONE FAVORED AREA WILL BE CLOSE
TO THE RED RIVER NEAR A STATIONARY FRONT...WITH A SECOND FAVORED AREA
IN SOUTHEAST TEXAS NEAR DEEPER MOISTURE. WILL THEREFORE NOT HAVE
ANY MENTION OF SHOWERS OR STORMS IN TAF.
09/GP
&&
.PREV DISCUSSION... /ISSUED 424 AM CDT MON AUG 12 2013/
REGIONAL RADARS WERE SHOWING A FEW CLUSTERS OF SHOWERS AND
THUNDERSTORMS MOVING EAST-NORTHEAST FROM APPROXIMATELY PLAINVIEW
TX TO LAWTON OK. THIS AREA OF PRECIPITATION WAS MASKING THE
POSITION OF THE NORTHWARD MOVING BOUNDARY THAT WAS IN PLACE OVER
THE DFW METROPLEX YESTERDAY AFTERNOON. IT IS POSSIBLE THAT THE
BOUNDARY IS NEAR THE LINE OF SHOWER AND THUNDERSTORM ACTIVITY
MENTIONED ABOVE...BUT A CHAOTIC WIND AND TEMPERATURE FIELD DUE TO
MULTIPLE OUTFLOW BOUNDARIES MADE THE FRONT DIFFICULT TO LOCATE ON
A SURFACE SUBJECTIVE ANALYSIS AT 08Z. EARLY MORNING WATER VAPOR
SATELLITE IMAGERY SHOWED AN ANTICYCLONIC CIRCULATION CENTERED
NEAR EL PASO WITH WESTERLY FLOW ALOFT OVER KS AND OKLAHOMA.
FURTHER NORTH...A STRONG SHORTWAVE TROUGH WAS EVIDENT NORTH OF
MINNESOTA...MOVING SOUTHEAST TOWARDS THE UPPER GREAT LAKES REGION.
TODAY THROUGH TUESDAY...ASSUMING THE FRONT CONTINUES TO MOVE NORTH
THIS MORNING...THERE WILL BE NO OBVIOUS FOCUS FOR AFTERNOON
THUNDERSTORMS TODAY THROUGH EARLY TUESDAY AFTERNOON ACROSS NORTH
TX. IN GENERAL WITH PERSISTENT SOUTHERLY FLOW AND MOSTLY SUNNY
SKIES...WE SHOULD SEE HIGHS CONTINUE TO TOP OUT IN THE UPPER 90S
TO JUST ABOVE 100 DEGREES FOR MOST LOCATIONS MONDAY AND TUESDAY.
THERE IS SOME CONCERN THAT THE CLUSTER OF STORMS LOCATED FROM
PLAINVIEW TO LAWTON WILL BE ABLE TO SEND SOME SORT OF CONSOLIDATED
OUTFLOW BOUNDARY SOUTH TOWARDS THE RED RIVER THIS MORNING. THE
RADAR PRESENTATION OF THIS CONVECTION AT 08Z DID NOT SEEM VIGOROUS
ENOUGH TO SEND A BOUNDARY SOUTH TO THE RED RIVER...HOWEVER A FEW
EARLY MORNING RUNS OF THE RAP AND THE NCEP 4 KM WRF SEEM TO BE
ADVERTISING THIS SCENARIO FOR THUNDERSTORM CONSIDERATIONS LATER
THIS AFTERNOON...EVEN THE 06Z NAM APPEARS TO BE INDICATING A
SUBTLE BOUNDARY NEAR THE RED RIVER. HOWEVER...THE CONSENSUS OF
MOST MODEL GUIDANCE SENDS THE FRONT NORTH TO THE KS/OK BORDER
TODAY...WELL REMOVED FROM NORTH TX. WITH LITTLE CONFIDENCE THAT A
SIGNIFICANT BOUNDARY WILL MOVE TO THE RED RIVER OR INTO NORTH TX
THIS MORNING...LEFT 10 POPS IN THE FORECAST WITHOUT ANY MENTION OF
THUNDERSTORMS THROUGH THIS AFTERNOON.
WITH MOST MODEL GUIDANCE BRINGING THE FRONT NORTH TO THE KS/OK
BORDER THIS AFTERNOON...THIS SHOULD SERVE AS A NICE FOCUS FOR
AFTERNOON THUNDERSTORM INITIATION. THE MINNESOTA UPPER LEVEL
TROUGH IS EXPECTED TO DIVE SOUTHEAST TODAY WHICH MARKS THE
BEGINNING OF A LARGE SCALE TROUGH THAT WILL BUILD OVER THE ENTIRE
EASTERN CONUS BY LATE THIS WEEK. THIS FIRST STRONG SHORTWAVE
TROUGH WILL TURN THE WESTERLIES ALOFT OVER KS/OK SLIGHTLY TO THE
SOUTH...RESULTING IN WEST-NORTHWEST FLOW ALOFT BY THIS EVENING.
WITH STRONGER DEEP LAYER SHEAR TO WORK WITH ALONG THE KS/OK
BORDER...AND STEERING FLOW ALOFT TILTING TO THE SOUTH THIS
EVENING...IT IS POSSIBLE FOR SOME ORGANIZED MCS TO PULL AWAY FROM
THE FRONT AND MOVE SOUTH TOWARDS THE RED RIVER BEFORE MIDNIGHT
TONIGHT. OVERALL THINK THAT THE CHANCES OF THIS ARE
SMALL...HOWEVER DID GO WITH A SMALL AREA OF 20 POPS JUST SOUTH OF
THE RED RIVER TO ACCOUNT FOR THIS SCENARIO. MOST MODEL GUIDANCE
INDICATES VIGOROUS CONVECTION ALONG THE KS/OK BORDER BY THIS
AFTERNOON...SO WE WILL HAVE TO WATCH THE EVOLUTION OF ANY MCS FOR
SOME POTENTIAL TO MOVE INTO NORTH TX THIS EVENING OR OVERNIGHT.
DURING THE DAY ON TUESDAY THE CONTINUED SOUTHEASTWARD PUSH OF THE
MINNESOTA UPPER TROUGH WILL HELP TILT THE FLOW ALOFT MORE TO THE
NORTHWEST OVER THE SOUTH PLAINS AS UPPER LEVEL RIDGING REORGANIZES
OVER THE SOUTHWESTERN CONUS. ANOTHER STRONG SHORTWAVE TROUGH IS
EXPECTED TO MOVE SOUTHEAST OVER THE WESTERN GREAT LAKES TUESDAY
AFTERNOON WHICH SHOULD HELP SEND THE KS/OK COLD FRONT SOUTH INTO
NORTH TX BY TUESDAY NIGHT. ALL MODELS SHOW NUMEROUS SHOWERS AND
THUNDERSTORMS ALONG THE FRONT TUESDAY AFTERNOON AND EVENING. THIS
WILL LIKELY CAUSE THE FRONT TO MOVE TO THE SOUTH FASTER...SO
GENERALLY FAVORED MODELS WITH A QUICKER FRONTAL PASSAGE IN THIS
FORECAST.
HAVE THUNDERSTORM CHANCES INCREASING FROM AROUND 20 PERCENT NEAR
THE RED RIVER TUESDAY AFTERNOON TO 50 TO 60 PERCENT NEAR THE RED
RIVER TUESDAY EVENING. HAVE POPS IN THE FORECAST TUESDAY NIGHT AS
FAR SOUTH AS WACO...HOWEVER CONFIDENCE IN THUNDERSTORMS DIMINISHES
FROM NORTH TO SOUTH ACROSS THE CWA. THUNDERSTORMS ARE MOST LIKELY
ALONG AND NORTH OF INTERSTATE 20 TUESDAY EVENING AND OVERNIGHT.
THERE IS SOME CHANCE THAT THESE STORMS WILL BE SEVERE AS THEY MOVE
INTO NORTH TX TUESDAY NIGHT...HOWEVER SEVERE WEATHER POTENTIAL IS
EXPECTED TO BE LIMITED BY THE STORMS MOVING INTO THE AREA AFTER
SUNSET.
ANY SEVERE STORMS WOULD LIKELY BE IN THE FORM OF A SMALL LINEAR
MCS AS DEEP LAYER BULK SHEAR IS FORECAST TO BE 30 TO 35 KTS ALONG
AND NORTH OF INTERSTATE 20. SHEAR WEAKENS TO THE SOUTH...AND
STORMS ARE NOT AS LIKELY TO MOVE SOUTH OF INTERSTATE 20 UNTIL LATE
TUESDAY EVENING...SO SEVERE WEATHER CHANCES TO THE SOUTH OF I-20
LOOK FAIRLY SMALL AT THIS TIME. DAMAGING WINDS WOULD BE THE MOST
LIKELY SEVERE WEATHER HAZARD...WITH CLOUD TO GROUND LIGHTNING AND
LOCALLY HEAVY RAINFALL POSSIBLE WITH ANY STORM.
NOCTURNAL CONVECTION USUALLY WEAKENS SUBSTANTIALLY NEAR DAWN IN
THE ABSENCE OF UPPER LEVEL SUPPORT. THINK THAT SHOWERS AND STORMS
ALONG THE FRONT WILL TEND TO WEAKEN EARLY WEDNESDAY MORNING
LEAVING SOME UNORGANIZED SHOWER AND THUNDERSTORM ACTIVITY NEAR THE
FRONT AS IT STALLS OUT WEDNESDAY MORNING. THE FRONT WILL MOST
LIKELY BE LOCATED JUST SOUTH OF INTERSTATE 20 AT THAT
TIME. ASSUMING THE FRONT STALLS OUT IN THIS LULL OF CONVECTIVE
ACTIVITY...THE STALLED OUT FRONT SHOULD SERVE AS A FOCUS FOR
THUNDERSTORM INITIATION WEDNESDAY AFTERNOON. WENT AHEAD AND PLACED
50 POPS ALONG THE EXPECTED POSITION OF THE FRONT...ROUGHLY IN
BETWEEN DFW AND WACO WITH LOWER POPS TO THE NORTH AND SOUTH DURING
THE DAY ON WEDNESDAY.
ADDITIONAL THUNDERSTORM ACTIVITY ALONG THE FRONT WEDNESDAY
AFTERNOON SHOULD SEND THE FRONT SOUTH OUT OF THE CWA BY WEDNESDAY
EVENING. AS A RESULT WENT AHEAD AND MOVED THE BEST POPS SOUTH FROM
WEDNESDAY AFTERNOON THROUGH THE OVERNIGHT HOURS. BY THURSDAY
MORNING...THE FRONT IS EXPECTED TO BE LOCATED JUST SOUTH OR
SOUTHWEST OF THE CWA.
THURSDAY...ASSUMING THE FRONT IS NOT IN THE CWA...CONFIDENCE IN
WHEN AND WHERE STORMS WILL DEVELOP ACROSS THE AREA IS SOMEWHAT
LOW. THE GFS CONTINUES TO INDICATE A SHORTWAVE TROUGH MOVING
TOWARDS THE CWA THURSDAY AFTERNOON OR EVENING WHICH COULD
CERTAINLY CAUSE ISOLATED STORMS TO DEVELOP WHEREVER THE GREATEST
LIFT OCCURS. KEPT POPS IN THE 20 TO 30 PERCENT RANGE AT THIS TIME
BECAUSE THE BEST MOISTURE AND INSTABILITY FOR STORMS IS EXPECTED
TO REMAIN SOUTH OF THE FRONT. WITH THE FRONTAL POSITION AT LEAST
SOMEWHAT DEPENDENT ON THE COVERAGE AND INTENSITY OF STORMS EACH
DAY...THIS FORECAST COULD CHANGE SIGNIFICANTLY DEPENDING ON WHERE
THE FRONT ACTUALLY IS AT THIS TIME. HOWEVER FOR NOW MOST GUIDANCE
KEEPS THE FRONT SOUTH OF THE CWA WHICH SHOULD DAMPEN THUNDERSTORM
CHANCES IN GENERAL.
RAIN COOLED AIR ON WEDNESDAY...AND COLD AIR ADVECTION BEHIND THE
COLD FRONT SHOULD KEEP TEMPERATURES BELOW NORMAL FROM WEDNESDAY
THROUGH THE END OF THE WEEK. THIS SHOULD PROVIDE SOME NICE RELIEF
FROM THE PREVIOUS TWO WEEKS OF 100 DEGREE HEAT. HIGHS WILL
GENERALLY BE HELD INTO THE MID TO UPPER 80S NORTH OF INTERSTATE 20
WITH HIGHS IN THE LOWER 90S TO THE SOUTH.
FRIDAY THROUGH MONDAY...THE GFS AND ECMWF BOTH INDICATE A STRONGER
SHORTWAVE TROUGH WILL BUILD OVER THE REGION BY FRIDAY BRINGING IN
AN UNUSUAL UPPER AIR PATTERN DOMINATED BY NORTHERLY FLOW ALOFT
OVER THE REGION THROUGH THE WEEKEND. IN GENERAL THIS PATTERN
FAVORS COOLER THAN NORMAL TEMPERATURES WITH LOW RAIN CHANCES DUE
TO DRIER CONTINENTAL AIR BEING ADVECTED INTO THE REGION. THE
FORECAST REFLECTS THESE GENERAL GUIDELINES. MAY HAVE TO INCLUDE
SOME POPS IN THE FORECAST AT A LATER DATE AS SMALLER SCALE
FEATURES BECOME BETTER RESOLVED...HOWEVER NO WIDESPREAD
PRECIPITATION IS EXPECTED AT THIS TIME. TEMPERATURES SHOULD RETURN
TO SEASONAL NORMALS BY MONDAY.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 100 80 99 78 90 / 10 10 10 30 50
WACO, TX 98 77 99 78 94 / 10 5 10 20 40
PARIS, TX 96 75 95 73 83 / 10 20 20 60 40
DENTON, TX 99 77 98 75 88 / 10 10 10 40 40
MCKINNEY, TX 99 78 99 76 87 / 10 10 20 40 50
DALLAS, TX 101 82 101 81 90 / 10 10 10 30 50
TERRELL, TX 100 78 99 77 89 / 10 10 10 30 50
CORSICANA, TX 100 78 100 78 94 / 10 10 10 20 50
TEMPLE, TX 96 74 98 75 94 / 10 10 10 10 30
MINERAL WELLS, TX 99 77 98 76 88 / 10 10 10 30 50
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/30
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
955 AM CDT MON AUG 12 2013
.UPDATE...
A TRANSITION DAY WITH LOW END MODERATE RAIN CHANCES. NORTHEASTERN-
CENTERED SURFACE HIGH...WITH THE WESTERN EXPANSION OF FLORIDA-BASED
MID-LEVEL RIDGING...WILL PROVIDE THE SUBSIDENCE TO INHIBIT MORE
WIDESPREAD RAINFALL (AS WAS EXPERIENCED YESTERDAY). A HIGHLY MOIST
AND UNSTABLE ENVIRONMENT STILL HAS THE POTENTIAL TO ALLOW SCATTERED
SHOWERS AND ISOLATED STORMS TO DEVELOP CLOSER TO THE COAST AND
TRACK NORTHEAST. AS EARLY AFTERNOON SURFACE TEMPERATURES ACHIEVE
THE LOWER TO MIDDLE 90S...AREAL COVERAGE SHOULD INCREASE A BIT
FURTHER INLAND OVER THE CENTRAL TO NORTHEASTERN FORECAST AREA. 31
&&
.PREV DISCUSSION... /ISSUED 612 AM CDT MON AUG 12 2013/
AVIATION...
UPPER LEVEL DISTURBANCE RESPONSIBLE FOR OUR CONVECTION THIS
WEEKEND IS MOVING OFF TO THE WEST OF OUR REGION. THIS WILL LEAD TO
LOWER COVERAGE OF SHRA/TSRA TODAY AND MORE SOUTHERLY LOW LEVEL
WINDS. WITH THE SHIFT IN WIND DIRECTION EXPECT ANY TSRA THAT DO
DEVELOP TO MOVE TO THE NORTH RATHER THAN NORTHWEST. 38
PREV DISCUSSION... /ISSUED 424 AM CDT MON AUG 12 2013/
DISCUSSION...
TROPICAL AIRMASS OVER SE TX HAS BEEN RESPONSIBLE FOR MAINLY SCT
SHOWERS AND THUNDERSTORMS. DAY TIME HEATING HAS INCREASED
INSTABILITY OVER NORTHERN PORTIONS OF SE TX RESULTING IN STRONG TO
ALMOST SEVERE STORMS WITH SMALL HAIL AND LOCALIZED HEAVY RAINFALL.
NOT AS OPTIMISTIC WITH RAIN CHANCES TODAY FOR A COUPLE OF REASONS.
FIRST 00Z 500MB ANALYSIS HAS UPPER LEVEL RIDGE AND HEIGHT RISES
OVER THE AREA. LOOKS LIKE TWO RIDGE CENTERS ARE TAKING SHAPE OVER
N TX AND BERMUDA RIDGE EDGING IN ACROSS FLORIDA. MODELS ARE
PRETTY CONSISTENT WITH KEEPING A FLAT RIDGE OVER MUCH OF TX AND N
GULF COAST. WATER VAPOR IMAGERY SHOWS UPPER LEVEL LOW NOW OVER
MEXICO SOUTH OF RIO GRANDE. THINK THIS WILL BE TOO FAR WAY AND TOO
WEAK TO IMPACT SE TX. GOES SOUNDER PRECIP WATER IMAGERY SHOWS
ABOUT 1.9-2 INCH PRECIP WATER OVER THE REGION BUT THE TREND HAS
BEEN THAT OF DRYING. LATEST HRRR AND 00Z WRF-ARW ALONG WITH
NAM/GFS REALLY ALL POINT TO BEST COVERAGE OF CONVECTION OVER E TX
AND SW LA. DECIDED TO KEEP AT LEAST SOME 30 POPS FOR EASTERN PARTS
OF THE FORECAST AREA BASED ON THESE TRENDS WITH 20 POPS ELSEWHERE.
IT WILL TAKE A WHILE TO REACH THE LOW 90S FOR CONVECTION TO START
TO REALLY INITIATE. COULD TAKE MORE HEATING IF MOISTURE CONTINUES
TO DECREASE. STILL WILL NEED TO WATCH FOR STRONG STORMS THAT
APPROACH SEVERE LEVELS ESPECIALLY WHERE THERE IS MAXIMUM HEATING
AND INSTABILITY. POTENTIAL STILL EXISTS FOR LOCALIZED HEAVY RAIN
WITH THE STRONGER STORMS.
TUE THROUGH THUR UPPER LEVEL RIDGE BUILDS OVER TX AND MOVES BACK
OVER S ROCKIES/GREAT BASIN BY THURSDAY. THIS RESULTS IN NW FLOW
ALOFT OVER THE REGION WITH A BROAD TROUGH OVER THE GREAT LAKES.
LOOKS LIKE BOTH THE GFS/ECMWF ARE TRYING TO DEEPEN THE TROUGH OVER
THE MISS RIVER VALLEY LATE FRI THROUGH SATURDAY. THE PATTERN
SUPPORTS A FRONTAL BOUNDARY PUSHING INTO SE TX LATE WED THROUGH
THUR. FRONT MAY PUSH TO THE COAST ON FRI BEFORE STALLING. FRONT
SHOULD BE A FOCUS FOR THUNDERSTORM ACTIVITY SO MAY HAVE A MORE WET
PATTERN DEVELOP FOR THE END OF THE WEEK. TIMING OF THE FRONT WILL
BE THE MAIN CHALLENGE WITH THE FORECAST. THINK A SLOWER FRONTAL
PUSH LIKE THE GFS MAY BE THE BEST SOLUTION RIGHT NOW. GIVEN THAT
UPPER LEVEL FLOW BECOMES MORE AMPLIFIED THUR/FRI...THINK FRONT
WILL TAKE ITS TIME GETTING INTO SE TX. FOR NOW WILL KEEP 20/3O
POPS FOR THE AREA MAINLY DUE TO UNCERTAINTY SURROUNDING THE TIMING
OF THE FRONT.
DRIER BOUNDARY LAYER AIR SHOULD REACH SE TX FRI INTO SAT SO THINK
RAIN CHANCES WILL DROP OFF FOR NEXT WEEKEND. UPPER LEVEL TROUGH
AXIS LOOKS TO PUSH BY ON SATURDAY PER GFS WHILE THE ECMWF HOLD THE
TROUGH MORE TO THE WEST OF THE GFS AND DOES NOT DISSIPATE THE
FRONT AS QUICKLY. MAY NEED TO HOLD ONTO SOME POPS FOR THE WEEKEND
BUT THINK DRIER BOUNDARY LAYER WILL LIMIT PRECIP. THE UPPER LEVEL
TROUGH DOES LIFT OFF TO THE NE LATE IN THE WEEKEND SO THINK A DRIER
FORECAST FOR PRECIP LOOKS REASONABLE.
LASTLY THE GFS IS TRYING TO DEVELOP A TROPICAL LOW PRESSURE IN
THE NW CARIB ON THUR AND MOVES IT INTO INTO THE GULF FRI/SAT.
GIVEN UPPER LEVEL PATTERN THAT DEVELOPS OVER THE N GULF FOR THE
WEEKEND...SHOULD ANYTHING DEVELOP TROPICALLY IT WILL BE IN A
HIGHLY SHEARED ENVIRONMENT. UPPER LEVEL TROUGH WILL ALSO LIKELY
TAKE THE SYSTEM WELL EAST OF THE AREA TOWARDS FL PANHANDLE ON
SUNDAY. THIS WILL BE SOMETHING TO KEEP AN EYE ON BUT OVERALL NOT
MUCH OF A CONCERN.
39
MARINE...
A FEW ISOLATED SHOWERS ACROSS THE COASTAL WATERS THIS MORNING BUT
COVERAGE WILL BE MUCH LESS TODAY THAN OVER THE WEEKEND. A
RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP LIGHT ONSHORE WINDS IN PLACE THROUGH THE MIDDLE OF THE WEEK.
A WEAK FRONT WILL APPROACH THE COAST LATE IN THE WEEK LEADING TO A
BRIEF PERIOD OF OFFSHORE WINDS. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 75 100 76 102 / 20 10 10 10 20
HOUSTON (IAH) 95 77 97 78 99 / 30 10 10 10 20
GALVESTON (GLS) 92 82 93 83 92 / 20 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
640 AM CDT MON AUG 12 2013
.AVIATION...
NO MAJOR CONCERNS THIS CYCLE. MOSTLY CLEAR SKIES EXPECTED WITH
SOUTHERLY FLOW OF 8-12 KTS EXPECTED NEXT 24-30 HOURS.
CONVECTION THIS AFTERNOON OR EVENING ACROSS TEXAS IS EXPECTED TO
BE WELL-REMOVED FROM THE TAF SITES. ONE FAVORED AREA WILL BE CLOSE
TO THE RED RIVER NEAR A STATIONARY FRONT...WITH A SECOND FAVORED AREA
IN SOUTHEAST TEXAS NEAR DEEPER MOISTURE. WILL THEREFORE NOT HAVE
ANY MENTION OF SHOWERS OR STORMS IN TAF.
09/GP
&&
.PREV DISCUSSION... /ISSUED 424 AM CDT MON AUG 12 2013/
REGIONAL RADARS WERE SHOWING A FEW CLUSTERS OF SHOWERS AND
THUNDERSTORMS MOVING EAST-NORTHEAST FROM APPROXIMATELY PLAINVIEW
TX TO LAWTON OK. THIS AREA OF PRECIPITATION WAS MASKING THE
POSITION OF THE NORTHWARD MOVING BOUNDARY THAT WAS IN PLACE OVER
THE DFW METROPLEX YESTERDAY AFTERNOON. IT IS POSSIBLE THAT THE
BOUNDARY IS NEAR THE LINE OF SHOWER AND THUNDERSTORM ACTIVITY
MENTIONED ABOVE...BUT A CHAOTIC WIND AND TEMPERATURE FIELD DUE TO
MULTIPLE OUTFLOW BOUNDARIES MADE THE FRONT DIFFICULT TO LOCATE ON
A SURFACE SUBJECTIVE ANALYSIS AT 08Z. EARLY MORNING WATER VAPOR
SATELLITE IMAGERY SHOWED AN ANTICYCLONIC CIRCULATION CENTERED
NEAR EL PASO WITH WESTERLY FLOW ALOFT OVER KS AND OKLAHOMA.
FURTHER NORTH...A STRONG SHORTWAVE TROUGH WAS EVIDENT NORTH OF
MINNESOTA...MOVING SOUTHEAST TOWARDS THE UPPER GREAT LAKES REGION.
TODAY THROUGH TUESDAY...ASSUMING THE FRONT CONTINUES TO MOVE NORTH
THIS MORNING...THERE WILL BE NO OBVIOUS FOCUS FOR AFTERNOON
THUNDERSTORMS TODAY THROUGH EARLY TUESDAY AFTERNOON ACROSS NORTH
TX. IN GENERAL WITH PERSISTENT SOUTHERLY FLOW AND MOSTLY SUNNY
SKIES...WE SHOULD SEE HIGHS CONTINUE TO TOP OUT IN THE UPPER 90S
TO JUST ABOVE 100 DEGREES FOR MOST LOCATIONS MONDAY AND TUESDAY.
THERE IS SOME CONCERN THAT THE CLUSTER OF STORMS LOCATED FROM
PLAINVIEW TO LAWTON WILL BE ABLE TO SEND SOME SORT OF CONSOLIDATED
OUTFLOW BOUNDARY SOUTH TOWARDS THE RED RIVER THIS MORNING. THE
RADAR PRESENTATION OF THIS CONVECTION AT 08Z DID NOT SEEM VIGOROUS
ENOUGH TO SEND A BOUNDARY SOUTH TO THE RED RIVER...HOWEVER A FEW
EARLY MORNING RUNS OF THE RAP AND THE NCEP 4 KM WRF SEEM TO BE
ADVERTISING THIS SCENARIO FOR THUNDERSTORM CONSIDERATIONS LATER
THIS AFTERNOON...EVEN THE 06Z NAM APPEARS TO BE INDICATING A
SUBTLE BOUNDARY NEAR THE RED RIVER. HOWEVER...THE CONSENSUS OF
MOST MODEL GUIDANCE SENDS THE FRONT NORTH TO THE KS/OK BORDER
TODAY...WELL REMOVED FROM NORTH TX. WITH LITTLE CONFIDENCE THAT A
SIGNIFICANT BOUNDARY WILL MOVE TO THE RED RIVER OR INTO NORTH TX
THIS MORNING...LEFT 10 POPS IN THE FORECAST WITHOUT ANY MENTION OF
THUNDERSTORMS THROUGH THIS AFTERNOON.
WITH MOST MODEL GUIDANCE BRINGING THE FRONT NORTH TO THE KS/OK
BORDER THIS AFTERNOON...THIS SHOULD SERVE AS A NICE FOCUS FOR
AFTERNOON THUNDERSTORM INITIATION. THE MINNESOTA UPPER LEVEL
TROUGH IS EXPECTED TO DIVE SOUTHEAST TODAY WHICH MARKS THE
BEGINNING OF A LARGE SCALE TROUGH THAT WILL BUILD OVER THE ENTIRE
EASTERN CONUS BY LATE THIS WEEK. THIS FIRST STRONG SHORTWAVE
TROUGH WILL TURN THE WESTERLIES ALOFT OVER KS/OK SLIGHTLY TO THE
SOUTH...RESULTING IN WEST-NORTHWEST FLOW ALOFT BY THIS EVENING.
WITH STRONGER DEEP LAYER SHEAR TO WORK WITH ALONG THE KS/OK
BORDER...AND STEERING FLOW ALOFT TILTING TO THE SOUTH THIS
EVENING...IT IS POSSIBLE FOR SOME ORGANIZED MCS TO PULL AWAY FROM
THE FRONT AND MOVE SOUTH TOWARDS THE RED RIVER BEFORE MIDNIGHT
TONIGHT. OVERALL THINK THAT THE CHANCES OF THIS ARE
SMALL...HOWEVER DID GO WITH A SMALL AREA OF 20 POPS JUST SOUTH OF
THE RED RIVER TO ACCOUNT FOR THIS SCENARIO. MOST MODEL GUIDANCE
INDICATES VIGOROUS CONVECTION ALONG THE KS/OK BORDER BY THIS
AFTERNOON...SO WE WILL HAVE TO WATCH THE EVOLUTION OF ANY MCS FOR
SOME POTENTIAL TO MOVE INTO NORTH TX THIS EVENING OR OVERNIGHT.
DURING THE DAY ON TUESDAY THE CONTINUED SOUTHEASTWARD PUSH OF THE
MINNESOTA UPPER TROUGH WILL HELP TILT THE FLOW ALOFT MORE TO THE
NORTHWEST OVER THE SOUTH PLAINS AS UPPER LEVEL RIDGING REORGANIZES
OVER THE SOUTHWESTERN CONUS. ANOTHER STRONG SHORTWAVE TROUGH IS
EXPECTED TO MOVE SOUTHEAST OVER THE WESTERN GREAT LAKES TUESDAY
AFTERNOON WHICH SHOULD HELP SEND THE KS/OK COLD FRONT SOUTH INTO
NORTH TX BY TUESDAY NIGHT. ALL MODELS SHOW NUMEROUS SHOWERS AND
THUNDERSTORMS ALONG THE FRONT TUESDAY AFTERNOON AND EVENING. THIS
WILL LIKELY CAUSE THE FRONT TO MOVE TO THE SOUTH FASTER...SO
GENERALLY FAVORED MODELS WITH A QUICKER FRONTAL PASSAGE IN THIS
FORECAST.
HAVE THUNDERSTORM CHANCES INCREASING FROM AROUND 20 PERCENT NEAR
THE RED RIVER TUESDAY AFTERNOON TO 50 TO 60 PERCENT NEAR THE RED
RIVER TUESDAY EVENING. HAVE POPS IN THE FORECAST TUESDAY NIGHT AS
FAR SOUTH AS WACO...HOWEVER CONFIDENCE IN THUNDERSTORMS DIMINISHES
FROM NORTH TO SOUTH ACROSS THE CWA. THUNDERSTORMS ARE MOST LIKELY
ALONG AND NORTH OF INTERSTATE 20 TUESDAY EVENING AND OVERNIGHT.
THERE IS SOME CHANCE THAT THESE STORMS WILL BE SEVERE AS THEY MOVE
INTO NORTH TX TUESDAY NIGHT...HOWEVER SEVERE WEATHER POTENTIAL IS
EXPECTED TO BE LIMITED BY THE STORMS MOVING INTO THE AREA AFTER
SUNSET.
ANY SEVERE STORMS WOULD LIKELY BE IN THE FORM OF A SMALL LINEAR
MCS AS DEEP LAYER BULK SHEAR IS FORECAST TO BE 30 TO 35 KTS ALONG
AND NORTH OF INTERSTATE 20. SHEAR WEAKENS TO THE SOUTH...AND
STORMS ARE NOT AS LIKELY TO MOVE SOUTH OF INTERSTATE 20 UNTIL LATE
TUESDAY EVENING...SO SEVERE WEATHER CHANCES TO THE SOUTH OF I-20
LOOK FAIRLY SMALL AT THIS TIME. DAMAGING WINDS WOULD BE THE MOST
LIKELY SEVERE WEATHER HAZARD...WITH CLOUD TO GROUND LIGHTNING AND
LOCALLY HEAVY RAINFALL POSSIBLE WITH ANY STORM.
NOCTURNAL CONVECTION USUALLY WEAKENS SUBSTANTIALLY NEAR DAWN IN
THE ABSENCE OF UPPER LEVEL SUPPORT. THINK THAT SHOWERS AND STORMS
ALONG THE FRONT WILL TEND TO WEAKEN EARLY WEDNESDAY MORNING
LEAVING SOME UNORGANIZED SHOWER AND THUNDERSTORM ACTIVITY NEAR THE
FRONT AS IT STALLS OUT WEDNESDAY MORNING. THE FRONT WILL MOST
LIKELY BE LOCATED JUST SOUTH OF INTERSTATE 20 AT THAT
TIME. ASSUMING THE FRONT STALLS OUT IN THIS LULL OF CONVECTIVE
ACTIVITY...THE STALLED OUT FRONT SHOULD SERVE AS A FOCUS FOR
THUNDERSTORM INITIATION WEDNESDAY AFTERNOON. WENT AHEAD AND PLACED
50 POPS ALONG THE EXPECTED POSITION OF THE FRONT...ROUGHLY IN
BETWEEN DFW AND WACO WITH LOWER POPS TO THE NORTH AND SOUTH DURING
THE DAY ON WEDNESDAY.
ADDITIONAL THUNDERSTORM ACTIVITY ALONG THE FRONT WEDNESDAY
AFTERNOON SHOULD SEND THE FRONT SOUTH OUT OF THE CWA BY WEDNESDAY
EVENING. AS A RESULT WENT AHEAD AND MOVED THE BEST POPS SOUTH FROM
WEDNESDAY AFTERNOON THROUGH THE OVERNIGHT HOURS. BY THURSDAY
MORNING...THE FRONT IS EXPECTED TO BE LOCATED JUST SOUTH OR
SOUTHWEST OF THE CWA.
THURSDAY...ASSUMING THE FRONT IS NOT IN THE CWA...CONFIDENCE IN
WHEN AND WHERE STORMS WILL DEVELOP ACROSS THE AREA IS SOMEWHAT
LOW. THE GFS CONTINUES TO INDICATE A SHORTWAVE TROUGH MOVING
TOWARDS THE CWA THURSDAY AFTERNOON OR EVENING WHICH COULD
CERTAINLY CAUSE ISOLATED STORMS TO DEVELOP WHEREVER THE GREATEST
LIFT OCCURS. KEPT POPS IN THE 20 TO 30 PERCENT RANGE AT THIS TIME
BECAUSE THE BEST MOISTURE AND INSTABILITY FOR STORMS IS EXPECTED
TO REMAIN SOUTH OF THE FRONT. WITH THE FRONTAL POSITION AT LEAST
SOMEWHAT DEPENDENT ON THE COVERAGE AND INTENSITY OF STORMS EACH
DAY...THIS FORECAST COULD CHANGE SIGNIFICANTLY DEPENDING ON WHERE
THE FRONT ACTUALLY IS AT THIS TIME. HOWEVER FOR NOW MOST GUIDANCE
KEEPS THE FRONT SOUTH OF THE CWA WHICH SHOULD DAMPEN THUNDERSTORM
CHANCES IN GENERAL.
RAIN COOLED AIR ON WEDNESDAY...AND COLD AIR ADVECTION BEHIND THE
COLD FRONT SHOULD KEEP TEMPERATURES BELOW NORMAL FROM WEDNESDAY
THROUGH THE END OF THE WEEK. THIS SHOULD PROVIDE SOME NICE RELIEF
FROM THE PREVIOUS TWO WEEKS OF 100 DEGREE HEAT. HIGHS WILL
GENERALLY BE HELD INTO THE MID TO UPPER 80S NORTH OF INTERSTATE 20
WITH HIGHS IN THE LOWER 90S TO THE SOUTH.
FRIDAY THROUGH MONDAY...THE GFS AND ECMWF BOTH INDICATE A STRONGER
SHORTWAVE TROUGH WILL BUILD OVER THE REGION BY FRIDAY BRINGING IN
AN UNUSUAL UPPER AIR PATTERN DOMINATED BY NORTHERLY FLOW ALOFT
OVER THE REGION THROUGH THE WEEKEND. IN GENERAL THIS PATTERN
FAVORS COOLER THAN NORMAL TEMPERATURES WITH LOW RAIN CHANCES DUE
TO DRIER CONTINENTAL AIR BEING ADVECTED INTO THE REGION. THE
FORECAST REFLECTS THESE GENERAL GUIDELINES. MAY HAVE TO INCLUDE
SOME POPS IN THE FORECAST AT A LATER DATE AS SMALLER SCALE
FEATURES BECOME BETTER RESOLVED...HOWEVER NO WIDESPREAD
PRECIPITATION IS EXPECTED AT THIS TIME. TEMPERATURES SHOULD RETURN
TO SEASONAL NORMALS BY MONDAY.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 100 80 99 78 90 / 10 10 10 30 50
WACO, TX 98 77 99 78 94 / 10 5 10 20 40
PARIS, TX 96 75 95 73 83 / 10 20 20 60 40
DENTON, TX 99 77 98 75 88 / 10 10 10 40 40
MCKINNEY, TX 99 78 99 76 87 / 10 10 20 40 50
DALLAS, TX 101 82 101 81 90 / 10 10 10 30 50
TERRELL, TX 100 78 99 77 89 / 10 10 10 30 50
CORSICANA, TX 100 78 100 78 94 / 10 10 10 20 50
TEMPLE, TX 96 74 98 75 94 / 10 10 10 10 30
MINERAL WELLS, TX 99 77 98 76 88 / 10 10 10 30 50
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
09/
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
612 AM CDT MON AUG 12 2013
.DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION.
&&
.AVIATION...
UPPER LEVEL DISTURBANCE RESPONSIBLE FOR OUR CONVECTION THIS
WEEKEND IS MOVING OFF TO THE WEST OF OUR REGION. THIS WILL LEAD TO
LOWER COVERAGE OF SHRA/TSRA TODAY AND MORE SOUTHERLY LOW LEVEL
WINDS. WITH THE SHIFT IN WIND DIRECTION EXPECT ANY TSRA THAT DO
DEVELOP TO MOVE TO THE NORTH RATHER THAN NORTHWEST. 38
&&
.PREV DISCUSSION... /ISSUED 424 AM CDT MON AUG 12 2013/
DISCUSSION...
TROPICAL AIRMASS OVER SE TX HAS BEEN RESPONSIBLE FOR MAINLY SCT
SHOWERS AND THUNDERSTORMS. DAY TIME HEATING HAS INCREASED
INSTABILITY OVER NORTHERN PORTIONS OF SE TX RESULTING IN STRONG TO
ALMOST SEVERE STORMS WITH SMALL HAIL AND LOCALIZED HEAVY RAINFALL.
NOT AS OPTIMISTIC WITH RAIN CHANCES TODAY FOR A COUPLE OF REASONS.
FIRST 00Z 500MB ANALYSIS HAS UPPER LEVEL RIDGE AND HEIGHT RISES
OVER THE AREA. LOOKS LIKE TWO RIDGE CENTERS ARE TAKING SHAPE OVER
N TX AND BERMUDA RIDGE EDGING IN ACROSS FLORIDA. MODELS ARE
PRETTY CONSISTENT WITH KEEPING A FLAT RIDGE OVER MUCH OF TX AND N
GULF COAST. WATER VAPOR IMAGERY SHOWS UPPER LEVEL LOW NOW OVER
MEXICO SOUTH OF RIO GRANDE. THINK THIS WILL BE TOO FAR WAY AND TOO
WEAK TO IMPACT SE TX. GOES SOUNDER PRECIP WATER IMAGERY SHOWS
ABOUT 1.9-2 INCH PRECIP WATER OVER THE REGION BUT THE TREND HAS
BEEN THAT OF DRYING. LATEST HRRR AND 00Z WRF-ARW ALONG WITH
NAM/GFS REALLY ALL POINT TO BEST COVERAGE OF CONVECTION OVER E TX
AND SW LA. DECIDED TO KEEP AT LEAST SOME 30 POPS FOR EASTERN PARTS
OF THE FORECAST AREA BASED ON THESE TRENDS WITH 20 POPS ELSEWHERE.
IT WILL TAKE A WHILE TO REACH THE LOW 90S FOR CONVECTION TO START
TO REALLY INITIATE. COULD TAKE MORE HEATING IF MOISTURE CONTINUES
TO DECREASE. STILL WILL NEED TO WATCH FOR STRONG STORMS THAT
APPROACH SEVERE LEVELS ESPECIALLY WHERE THERE IS MAXIMUM HEATING
AND INSTABILITY. POTENTIAL STILL EXISTS FOR LOCALIZED HEAVY RAIN
WITH THE STRONGER STORMS.
TUE THROUGH THUR UPPER LEVEL RIDGE BUILDS OVER TX AND MOVES BACK
OVER S ROCKIES/GREAT BASIN BY THURSDAY. THIS RESULTS IN NW FLOW
ALOFT OVER THE REGION WITH A BROAD TROUGH OVER THE GREAT LAKES.
LOOKS LIKE BOTH THE GFS/ECMWF ARE TRYING TO DEEPEN THE TROUGH OVER
THE MISS RIVER VALLEY LATE FRI THROUGH SATURDAY. THE PATTERN
SUPPORTS A FRONTAL BOUNDARY PUSHING INTO SE TX LATE WED THROUGH
THUR. FRONT MAY PUSH TO THE COAST ON FRI BEFORE STALLING. FRONT
SHOULD BE A FOCUS FOR THUNDERSTORM ACTIVITY SO MAY HAVE A MORE WET
PATTERN DEVELOP FOR THE END OF THE WEEK. TIMING OF THE FRONT WILL
BE THE MAIN CHALLENGE WITH THE FORECAST. THINK A SLOWER FRONTAL
PUSH LIKE THE GFS MAY BE THE BEST SOLUTION RIGHT NOW. GIVEN THAT
UPPER LEVEL FLOW BECOMES MORE AMPLIFIED THUR/FRI...THINK FRONT
WILL TAKE ITS TIME GETTING INTO SE TX. FOR NOW WILL KEEP 20/3O
POPS FOR THE AREA MAINLY DUE TO UNCERTAINTY SURROUNDING THE TIMING
OF THE FRONT.
DRIER BOUNDARY LAYER AIR SHOULD REACH SE TX FRI INTO SAT SO THINK
RAIN CHANCES WILL DROP OFF FOR NEXT WEEKEND. UPPER LEVEL TROUGH
AXIS LOOKS TO PUSH BY ON SATURDAY PER GFS WHILE THE ECMWF HOLD THE
TROUGH MORE TO THE WEST OF THE GFS AND DOES NOT DISSIPATE THE
FRONT AS QUICKLY. MAY NEED TO HOLD ONTO SOME POPS FOR THE WEEKEND
BUT THINK DRIER BOUNDARY LAYER WILL LIMIT PRECIP. THE UPPER LEVEL
TROUGH DOES LIFT OFF TO THE NE LATE IN THE WEEKEND SO THINK A
DRIER FORECAST FOR PRECIP LOOKS REASONABLE.
LASTLY THE GFS IS TRYING TO DEVELOP A TROPICAL LOW PRESSURE IN
THE NW CARIB ON THUR AND MOVES IT INTO INTO THE GULF FRI/SAT.
GIVEN UPPER LEVEL PATTERN THAT DEVELOPS OVER THE N GULF FOR THE
WEEKEND...SHOULD ANYTHING DEVELOP TROPICALLY IT WILL BE IN A
HIGHLY SHEARED ENVIRONMENT. UPPER LEVEL TROUGH WILL ALSO LIKELY
TAKE THE SYSTEM WELL EAST OF THE AREA TOWARDS FL PANHANDLE ON
SUNDAY. THIS WILL BE SOMETHING TO KEEP AN EYE ON BUT OVERALL NOT
MUCH OF A CONCERN.
39
MARINE...
A FEW ISOLATED SHOWERS ACROSS THE COASTAL WATERS THIS MORNING BUT
COVERAGE WILL BE MUCH LESS TODAY THAN OVER THE WEEKEND. A
RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP LIGHT ONSHORE WINDS IN PLACE THROUGH THE MIDDLE OF THE WEEK.
A WEAK FRONT WILL APPROACH THE COAST LATE IN THE WEEK LEADING TO A
BRIEF PERIOD OF OFFSHORE WINDS. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 77 99 77 99 / 20 10 10 10 20
HOUSTON (IAH) 95 77 97 77 96 / 30 10 10 10 20
GALVESTON (GLS) 92 81 93 81 92 / 30 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...99
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
424 AM CDT MON AUG 12 2013
.DISCUSSION...
TROPICAL AIRMASS OVER SE TX HAS BEEN RESPONSIBLE FOR MAINLY SCT
SHOWERS AND THUNDERSTORMS. DAY TIME HEATING HAS INCREASED
INSTABILITY OVER NORTHERN PORTIONS OF SE TX RESULTING IN STRONG TO
ALMOST SEVERE STORMS WITH SMALL HAIL AND LOCALIZED HEAVY RAINFALL.
NOT AS OPTIMISTIC WITH RAIN CHANCES TODAY FOR A COUPLE OF REASONS.
FIRST 00Z 500MB ANALYSIS HAS UPPER LEVEL RIDGE AND HEIGHT RISES
OVER THE AREA. LOOKS LIKE TWO RIDGE CENTERS ARE TAKING SHAPE OVER
N TX AND BERMUDA RIDGE EDGING IN ACROSS FLORIDA. MODELS ARE
PRETTY CONSISTENT WITH KEEPING A FLAT RIDGE OVER MUCH OF TX AND N
GULF COAST. WATER VAPOR IMAGERY SHOWS UPPER LEVEL LOW NOW OVER
MEXICO SOUTH OF RIO GRANDE. THINK THIS WILL BE TOO FAR WAY AND TOO
WEAK TO IMPACT SE TX. GOES SOUNDER PRECIP WATER IMAGERY SHOWS
ABOUT 1.9-2 INCH PRECIP WATER OVER THE REGION BUT THE TREND HAS
BEEN THAT OF DRYING. LATEST HRRR AND 00Z WRF-ARW ALONG WITH
NAM/GFS REALLY ALL POINT TO BEST COVERAGE OF CONVECTION OVER E TX
AND SW LA. DECIDED TO KEEP AT LEAST SOME 30 POPS FOR EASTERN PARTS
OF THE FORECAST AREA BASED ON THESE TRENDS WITH 20 POPS ELSEWHERE.
IT WILL TAKE A WHILE TO REACH THE LOW 90S FOR CONVECTION TO START
TO REALLY INITIATE. COULD TAKE MORE HEATING IF MOISTURE CONTINUES
TO DECREASE. STILL WILL NEED TO WATCH FOR STRONG STORMS THAT
APPROACH SEVERE LEVELS ESPECIALLY WHERE THERE IS MAXIMUM HEATING
AND INSTABILITY. POTENTIAL STILL EXISTS FOR LOCALIZED HEAVY RAIN
WITH THE STRONGER STORMS.
TUE THROUGH THUR UPPER LEVEL RIDGE BUILDS OVER TX AND MOVES BACK
OVER S ROCKIES/GREAT BASIN BY THURSDAY. THIS RESULTS IN NW FLOW
ALOFT OVER THE REGION WITH A BROAD TROUGH OVER THE GREAT LAKES.
LOOKS LIKE BOTH THE GFS/ECMWF ARE TRYING TO DEEPEN THE TROUGH OVER
THE MISS RIVER VALLEY LATE FRI THROUGH SATURDAY. THE PATTERN
SUPPORTS A FRONTAL BOUNDARY PUSHING INTO SE TX LATE WED THROUGH
THUR. FRONT MAY PUSH TO THE COAST ON FRI BEFORE STALLING. FRONT
SHOULD BE A FOCUS FOR THUNDERSTORM ACTIVITY SO MAY HAVE A MORE WET
PATTERN DEVELOP FOR THE END OF THE WEEK. TIMING OF THE FRONT WILL
BE THE MAIN CHALLENGE WITH THE FORECAST. THINK A SLOWER FRONTAL
PUSH LIKE THE GFS MAY BE THE BEST SOLUTION RIGHT NOW. GIVEN THAT
UPPER LEVEL FLOW BECOMES MORE AMPLIFIED THUR/FRI...THINK FRONT
WILL TAKE ITS TIME GETTING INTO SE TX. FOR NOW WILL KEEP 20/3O
POPS FOR THE AREA MAINLY DUE TO UNCERTAINTY SURROUNDING THE TIMING
OF THE FRONT.
DRIER BOUNDARY LAYER AIR SHOULD REACH SE TX FRI INTO SAT SO THINK
RAIN CHANCES WILL DROP OFF FOR NEXT WEEKEND. UPPER LEVEL TROUGH
AXIS LOOKS TO PUSH BY ON SATURDAY PER GFS WHILE THE ECMWF HOLD THE
TROUGH MORE TO THE WEST OF THE GFS AND DOES NOT DISSIPATE THE
FRONT AS QUICKLY. MAY NEED TO HOLD ONTO SOME POPS FOR THE WEEKEND
BUT THINK DRIER BOUNDARY LAYER WILL LIMIT PRECIP. THE UPPER LEVEL
TROUGH DOES LIFT OFF TO THE NE LATE IN THE WEEKEND SO THINK A
DRIER FORECAST FOR PRECIP LOOKS REASONABLE.
LASTLY THE GFS IS TRYING TO DEVELOP A TROPICAL LOW PRESSURE IN
THE NW CARIB ON THUR AND MOVES IT INTO INTO THE GULF FRI/SAT.
GIVEN UPPER LEVEL PATTERN THAT DEVELOPS OVER THE N GULF FOR THE
WEEKEND...SHOULD ANYTHING DEVELOP TROPICALLY IT WILL BE IN A
HIGHLY SHEARED ENVIRONMENT. UPPER LEVEL TROUGH WILL ALSO LIKELY
TAKE THE SYSTEM WELL EAST OF THE AREA TOWARDS FL PANHANDLE ON
SUNDAY. THIS WILL BE SOMETHING TO KEEP AN EYE ON BUT OVERALL NOT
MUCH OF A CONCERN.
39
&&
.MARINE...
A FEW ISOLATED SHOWERS ACROSS THE COASTAL WATERS THIS MORNING BUT
COVERAGE WILL BE MUCH LESS TODAY THAN OVER THE WEEKEND. A
RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP LIGHT ONSHORE WINDS IN PLACE THROUGH THE MIDDLE OF THE WEEK.
A WEAK FRONT WILL APPROACH THE COAST LATE IN THE WEEK LEADING TO A
BRIEF PERIOD OF OFFSHORE WINDS. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 77 99 77 99 / 20 10 10 10 20
HOUSTON (IAH) 95 77 97 77 96 / 30 10 10 10 20
GALVESTON (GLS) 92 81 93 81 92 / 30 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS SPOKANE WA
421 PM PDT Tue Aug 13 2013
.SYNOPSIS...
A warming and drying trend arrives Wednesday and lingers into
Thursday. A weak cold front will move into the Cascades Thursday
afternoon, then edges across the Inland NW Friday and Saturday.
This will bring a chance for light showers and a few thunderstorms,
along with near normal temperatures and locally breezy winds.
Seasonal temperatures and dry conditions will return Sunday into
early next week.
&&
.DISCUSSION...
Tonight: It appears as though there are only a couple of spots of
concern for thunderstorms for the remainder of the afternoon into
the evening. The Blue Mountains, the Camas Prairie and the
mountains of the Idaho Panhandle. Synoptic scale forcing is weak
region wide. As of 2 PM, a small scale vorticity max was moving
out of the southern Idaho Panhandle into western Montana. This
mesoscale feature should enhance the thunderstorm potential in
northwest Montana this evening. The RUC surface CAPE/CIN analysis
suggests that Shoshone, Boundary, Bonner and Pend Oreille counties
are essentially uncapped with as much as 2000 J/KG of surface
based instability. The HRRR suggests that a few thunderstorms will
develop between 4 PM and 6 PM over central and southern Shoshone
county. It will be interesting to see if convection will develop
in the wake of the departing vorticity center. Forecasters usually
imply that there is subsidence behind these small vort maxes to
suppress convection. I am more confident that a storm or two will
develop over the Blues and over the peaks near Bonners Ferry. The
threat for thunderstorms will decrease quickly this evening with
the loss of surface heating. By 8 PM, look for clearing skies
region-wide.
Wednesday: Hot temperatures will return on Wednesday with low to
mid 90s common over the Inland Northwest. Both the NAM and GFS
forecast a bit of moisture at 700mb Wednesday morning, advancing
northward through the Columbia Basin. This will probably not be
enough moisture to produce high based showers, but we will need to
monitor satellite and radar imagery tonight for the potential of
some light, high based showers in the morning. Otherwise, large
scale subsidence under a building upper ridge axis will cause
temperatures to warm a good 3 to 6 degrees tomorrow over today.
/GKoch
Wednesday night through Saturday: Models are in strong agreement
that the trof of low pressure currently spinning over the Gulf of
AK will eject east and pass through the Inland NW ushering a cool
front across the region. This will bring a chance for showers and
a few thunderstorms along with a cooling trend, and a slight
increase in winds.
The cool front will be reaching the Cascades around mid to late
afternoon on Thursday then slowly trickle across Ern Wa and Nrn
ID during the next 48 hours...barely clearing ID and Ern OR by
Saturday afternoon. This is exceptionally slower then models were
forecasting 24 hours ago but does make sense based on how the
upper-level jet parallels the front. So what does this mean? Well,
there are a few items of interest that could alter the forecast.
All models agree that there will be a rich but narrow fetch of
subtropical moisture absorbed into the system...running
along/ahead of the frontal boundary. So increased clouds are a
definite but given the slow movement of the front and weakening
thermal structure of the front upon crossing into Ern WA...lift
along the frontal boundary will be mediocre. As such,
precipitation along the front will be light and generally in a
slow, top-down saturation regime. This does not mean the region
will escape dry for better chances for precipitation will come in
two other forms.
The first will focus on smaller shortwaves swinging around the parent
low and tracking SW to NE along the baroclinic/frontal zone. GFS
is most robust with these waves but other models do show these
features in one form or another and looking at current water
vapor, the first wave that will swing through on Thursday is
evident via sharp area of darkening near 46N/155W. These are the
waves that tend to bring a quick burst of showers along slow
moving frontal systems that start off looking rather dry as this
did on yesterday`s models. The second feature will be convection
(ie thunderstorms). This pattern does not look overly impressive
or unstable for thunderstorms but it is August and timing will be
key. We did maintain a small threat for thunder over the Cascades
Thursday aftn however clouds should thickening throughout the day
and I am not real confident we can achieve the 500 J/kg of sb CAPE
showing up on the models Thursday aftn in this area. A better
threat for thunderstorms will come across Ern WA and ID Panhandle
Friday afternoon and Saturday as the front trickles this
way/stalls and works in conjunction with peak heating. Model
soundings indicate a modest layer of CIN for most locations away
from the far northern mountains so the lift along the front will
be necessary to lift these parcels and utilize the instability
but given the weakening nature of the front, we kept the main
threat for thunderstorms across the mountains or slightly
downstream of the steering flow.
All things considered, models are generally indicating light pcpn
with this event with the exception of the more robust GFS which
has a few quarter inch bull-eyes...one over the NE Mtns and
second near the Blue Mtns...and for reasoning above...the forecast
may need to trend wetter as these two features become more
apparent. /sb
Saturday Night through Tuesday Night: As the trough that brought
the chance for showers and thunderstorms to much of the region
exits to the east Saturday evening into Sunday we will see slight
chance remain for some showers and isolated t-storms for mainly
the northern ID Panhandle. As this pushes to the east our region
will be left with a general westerly flow. Most of the moisture
with this flow will remain to our north keeping the chance for
precipitation low. Also with the zonal flow we will not see many
changes in our temperatures with most areas sitting in the 80s for
highs and upper 50s to lower 60s for overnight lows. Winds will
die off from the breezy conditions we saw Saturday and look to
remain seasonal for the early part of next week. Models are
hinting at a wave dropping down from the Gulf of Alaska during the
middle part of next week...but with consistency between the
solutions lacking we will hold off on any major changes to the
forecast that far out for now. /Fliehman
&&
.AVIATION...
00Z TAFS: VFR conditions over the next 24 hours, with high
pressure building in. A few showers and isolated storms will be
found near the ID mountains, mainly east/south of KCOE/KLWS,
before 03Z. Otherwise look for a few middle and high clouds and
light diurnal winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 62 92 66 89 65 85 / 10 10 0 0 10 20
Coeur d`Alene 57 92 60 90 60 85 / 10 10 0 0 10 20
Pullman 51 92 54 90 57 86 / 0 10 0 0 10 20
Lewiston 64 100 66 98 66 94 / 10 0 0 0 0 10
Colville 53 95 57 93 59 87 / 0 10 0 10 20 20
Sandpoint 51 89 53 90 56 87 / 10 10 0 0 10 20
Kellogg 56 91 59 90 57 89 / 20 0 0 0 10 20
Moses Lake 59 95 64 93 65 90 / 10 10 0 10 10 10
Wenatchee 64 93 69 91 67 89 / 10 10 0 10 10 20
Omak 60 95 63 93 63 90 / 0 10 10 10 10 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 PM CDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 934 PM CDT SUN AUG 11 2013
WORKING ON AN UPDATE TO THE DENSE FOG ADVISORY TO INCLUDE CLARK
COUNTY AND WILL ALSO BUMP UP THE START TIME. UPPING THE START TIME
SINCE DENSE FOG IS QUICKLY FORMING IN CENTRAL WISCONSIN WITH SKIES
CLEARING. UPDATE COMING OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 248 PM CDT SUN AUG 11 2013
MAIN FORECAST CONCERNS ARE ON PRECIPITATION TONIGHT AND DENSE FOG
POTENTIAL TONIGHT INTO MONDAY MORNING.
CURRENTLY...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER
MUCH OF THE U.S. AND CANADIAN ROCKIES...WHILE TROUGHING DOMINATED
SOUTHEAST CANADA. THE FORECAST AREA RESIDES IN WEST-NORTHWEST
FLOW...WITH SHORTWAVES OF NOTE OVER NORTHEAST IOWA...SOUTHERN
MANITOBA AND A MUCH STRONGER ONE OVER NORTHERN MANITOBA. THE
NORTHEAST IOWA SHORTWAVE...COMBINED WITH A LOW TO MID LEVEL
FRONTOGENESIS ZONE AND A RIGHT ENTRANCE REGION OF AN 80 KT UPPER
JET STREAK IN NORTHERN WI...HAS HELPED TO KEEP SOME SHOWER
ACTIVITY GOING ACROSS NORTHERN IOWA THROUGH THE AFTERNOON. ALSO
PLENTY OF CLOUDS EXIST ACROSS THE FORECAST AREA...RESULTING FROM
DEEP LOW LEVEL MOISTURE SEEN ON THE 12Z MPX SOUNDING AND THE LACK
OF MUCH WIND FLOW TO ADVECT DRIER AIR SEEN ACROSS NORTH DAKOTA AND
NORTHERN MN. THE DRIER AIR LIES BEHIND A SURFACE TROUGH STRETCHING
FROM EASTERN NEBRASKA INTO NORTHWEST WI. A FEW SHOWERS HAVE FORMED
ON THIS TROUGH ACROSS EAST CENTRAL MN. FARTHER SOUTH...A WARM
FRONT ENHANCED BY OUTFLOW FROM THE SHOWERS WAS PRESENT STRETCHING
ALONG US-20 IN IOWA.
SYNOPTIC OVERVIEW...
FOCUS IS MOSTLY ON THE SHORTWAVE OVER NORTHERN MANITOBA. MODELS PROG
THIS SHORTWAVE TO DROP SOUTHEAST INTO UPPER MICHIGAN ON MONDAY. THIS
SHORTWAVE ALLOWS UPPER TROUGHING TO MOVE INTO THE FORECAST AREA...
AND SIMULTANEOUSLY HELPS GIVE THE SURFACE TROUGH IN MN A PUSH
SOUTHEAST. BY 12Z MONDAY...THE TROUGH...LIKELY NOW A COLD
FRONT...SHOULD BE SOUTHEAST OF THE AREA. THERE ARE ALSO
INDICATIONS OF AN INVERTED SURFACE TROUGH LINGERING BACK EXTENDING
NORTHWEST TO SOUTHEAST OVER CENTRAL/EASTERN WI...ASSOCIATED WITH
THAT SHORTWAVE DROPPING INTO UPPER MI.
HAZARDS...
DENSE FOG CONCERNS TONIGHT GIVEN RECENT RAINS...LIGHT WINDS...LATE
DAY CLEARING AND SMALL TEMP/DEW POINT SPREADS ALREADY.
DETAILS...
SHOWERS IN EAST CENTRAL MINNESOTA MAY TRY TO DROP DOWN INTO
NORTHWESTERN SECTIONS OF THE FORECAST AREA THIS EVENING.
HOWEVER...THEY ARE HIGHLY DIURNALLY DRIVEN...THUS ONCE HEATING
ENDS THEY SHOULD FALL APART QUICKLY. INCLUDED SOME 20 PERCENT
CHANCES FOR THEM FOR A FEW HOURS THIS EVENING. MEANWHILE...TO THE
SOUTH...ONGOING SHOWERS AND STORMS ACROSS NORTHEAST IOWA MAY
PERSIST THROUGH MUCH OF THE EVENING...SUPPORTED BY THE SHORTWAVE
TRACKING ACROSS NORTHEAST IOWA...THE LOW/MID LEVEL F-GEN AND RIGHT
ENTRANCE REGION. HOWEVER...AS THE UPPER FLOW TURNS MORE
NORTHWESTERLY... ANTICIPATING THESE FORCING FEATURES TO DROP
SOUTHEAST AND HELP DIMINISH THE PRECIPITATION. DID KEEP 20-40
PERCENT CHANCES GOING AFTER MIDNIGHT JUST IN CASE PRECIP HOLDS
ON A BIT LONGER THAN EXPECTED.
CONCERN THEN SHIFTS TO FOG GIVEN RECENT RAIN. CLOUDS OVER THE
FORECAST AREA...PARTICULARLY OVER THE NORTHERN HALF...SHOULD CLEAR
OUT THIS EVENING. WINDS LOOK TO STAY FAIRLY LIGHT THROUGH THE
NIGHT...EVEN AFTER THE TROUGH/FRONTAL PASSAGE. ITS WORTH NOTING
THAT WINDS DO PICK UP AT 950MB INTO THE 10-20 KT RANGE BY 12Z...
HOWEVER...THESE ARE ABOVE A 3C FRONTAL INVERSION. THUS...THEY SHOULD
NOT IMPACT THE FOG POTENTIAL MUCH. IN FACT...11.00Z/06Z/12Z HIRES
ARW/NMM AND 11.09Z SREF VISIBILITY PROGS SHOW PRETTY MUCH A SOLID
AREA OF FOG OVER SOUTHEAST MN...NORTHERN PARTS OF IOWA AND MUCH OF
SOUTHERN WI. ADDED MENTION OF FOG EARLIER ACROSS MUCH OF THE
FORECAST AREA...AND NOW HAVE RAISED THE COVERAGE TO WIDESPREAD IN A
CORRIDOR FROM SOUTHEAST MINNESOTA EAST INTO JACKSON...JUNEAU...ADAMS
AND VERNON COUNTIES OF WI. THIS AREA HAS ALSO BEEN INCLUDED IN A
DENSE FOG ADVISORY...SINCE FROM A REGIONAL PERSPECTIVE SEEMS TO
HAVE THE HIGHEST PROBABILITY OF METEOROLOGICAL CONDITIONS
FAVORABLE FOR DENSE FOG. THE ADVISORY MAY HAVE TO BE EXPANDED
SOUTH...ESPECIALLY IF SKIES END UP CLEARING THERE.
FOR MONDAY...COOLER AIR ALOFT UNDER THE UPPER TROUGHING COMBINED
WITH THE INVERTED SURFACE TROUGH...DAYTIME HEATING AND LINGERING LOW
LEVEL MOISTURE SHOULD ALLOW FOR ISOLATED/SCATTERED SHOWERS TO FORM
ALONG/NORTHEAST OF I-94. MLCAPE VALUES ALONG THE INVERTED TROUGH ARE
IN THE 100-300 J/KG AT 18Z...ENOUGH MAYBE TO GET A FEW
THUNDERSTORMS. BETTER INSTABILITY IS OFF TOWARDS SOUTHEAST WI WITH
HELP FROM LAKE BREEZE CONVERGENCE. ONCE THE FOG AND ASSOCIATED LOW
STRATUS MIX OUT A FEW HOURS AFTER SUNRISE...RELATIVELY BREEZY
NORTHWEST WINDS APPEAR TO SET UP. 850MB TEMPS IN THE 10-14C RANGE
SUPPORT HIGHS IN THE MID 70S TO LOW 80S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 PM CDT SUN AUG 11 2013
MUCH OF THE ENTIRE LONG TERM PERIOD IS DOMINATED BY RIDGING OVER THE
WESTERN U.S. AND TROUGHING IN THE EASTERN U.S....A POSITIVE PNA
PATTERN THAT RESULTS IN COOLER AND DRIER THAN NORMAL WEATHER. AT THE
SURFACE...CANADIAN HIGH PRESSURE IS PROGGED TO BUILD INTO THE AREA
MONDAY NIGHT AND TUESDAY...SIT OVER THE AREA TUESDAY NIGHT THROUGH
WEDNESDAY...THEN ONLY SLOWLY DRIFT OFF TOWARDS THE EASTERN GREAT
LAKES THIS WEEKEND. DRY AIR ACCOMPANYING THE HIGH LOOKS TO KEEP THE
BULK OF THE LONG TERM PERIOD DRY. IN FACT...PRECIPITABLE WATER
VALUES ARE FORECAST BETWEEN 50-70 PERCENT OF NORMAL FOR TUESDAY
THROUGH THURSDAY. THIS SHOULD RESULT IN DECENT MIXING OF DEW POINTS
DURING THE AFTERNOONS.
THE ONLY FEATURE REALLY OF INTEREST FOR POTENTIAL PRECIPITATION IS A
SHORTWAVE TROUGH THAT DROPS DOWN THROUGH THE NORTHWEST FLOW INTO THE
AREA THURSDAY NIGHT AND FRIDAY. BOTH THE 11.12Z GFS/CANADIAN PRODUCE
SOME LIGHT PRECIPITATION WITH IT OVER WESTERN AND NORTHERN SECTIONS
OF THE FORECAST AREA...WHEREAS THE 11.00Z/11.12Z ECMWF IS DRY. FROM
A CONSENSUS STANDPOINT...HAVE CONTINUED TO CARRY A 20 PERCENT CHANCE
TO ACCOUNT FOR THE GFS/CANADIAN. HOWEVER...LATER FORECASTS WILL BE
ABLE TO GO DRY IF THE GFS/CANADIAN TREND TOWARDS THE ECMWF.
TEMPERATURE WISE...850MB TEMP ANOMALIES ARE PROGGED TO BOTTOM OUT
BETWEEN 1-1.5C BELOW NORMAL FOR TUESDAY AND WEDNESDAY...READINGS OF
8C EAST TO 10C WEST. THUS THIS WILL BE THE COLDEST PERIOD WITH HIGHS
IN THE 70S. LOWS ARE LIKELY GOING TO DIP INTO THE 40S AT THE TYPICAL
COLD SPOTS TUESDAY NIGHT AND WEDNESDAY NIGHT WITH THE HIGH
OVERHEAD...WHICH WILL ALSO BE THE MOST FAVORABLE TIME PERIODS FOR
VALLEY FOG. VALLEY FOG IS ALSO POSSIBLE MONDAY NIGHT...BUT WINDS
WITH THE INCOMING HIGH MAY RESTRICT SOME OF THE COVERAGE. SLOW
WARMING OF 850MB TEMPS AND ANOMALIES IS FORECAST FOR THURSDAY AND
BEYOND...PEAKING AT 12C EAST TO 15C WEST AND AROUND NORMAL FOR
ANOMALY BY SUNDAY. THUS TEMPERATURES SHOULD SLOWLY CLIMB TOO EACH
DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1142 PM CDT SUN AUG 11 2013
WITH SKIES CLEARING OUT...DENSE FOG HAS QUICKLY FORMED ACROSS MUCH
OF THE REGION. RST HAS ALREADY DROPPED TO 1/4SM AND EXPECT THAT
LSE WILL FOLLOW SUIT SHORTLY. SKY COVER IS THE ONLY THING HOLDING
BACK THE FOG FROM BECOMING MORE WIDESPREAD AS THE UPPER LEVEL
PATTERN HAS SOMEWHAT STALLED. FROM TAKING A LOOK DOWN INTO THE
VALLEY FROM THE OFFICE WHICH IS UP IN THE BLUFFS...THERE IS A
STRATUS LAYER DEVELOPING IN THE RIVER CHANNEL. SO...EXPECT THAT
CONDITIONS WILL CONTINUE TO DROP...JUST PERHAPS A LITTLE SLOWLY
SICNE THE UPPER LEVEL CLOUD COVER IS IN PLACE. CONDITIONS WILL
RAPIDLY IMPROVE TOMORROW MORNING AS DRIER AIR MOVES IN AND THE
SKIES CLEAR OUT. CONDITIONS MAY BE FAVORABLE FOR VALLEY FOG AGAIN
MONDAY NIGHT INTO TUESDAY MORNING...BUT IT SHOULD STAY VFR THROUGH
6Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR WIZ029-032>034-
041>044-053.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT MONDAY FOR MNZ079-086>088-
094>096.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS TUCSON AZ
210 AM MST WED AUG 14 2013
.SYNOPSIS...INCREASING MOISTURE WILL PROVIDE GREATER COVERAGE OF
SHOWERS AND THUNDERSTORMS STARTING TODAY AND CONTINUING INTO EARLY
NEXT WEEK. OTHERWISE...STRONG HIGH PRESSURE ALOFT WILL RESULT IN
ABOVE NORMAL DAYTIME TEMPERATURES ACROSS MUCH OF THE AREA THROUGH
THIS WEEKEND.
&&
.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED 30-40 DBZ ECHOES OVER
SOUTH-CENTRAL COCHISE COUNTY AT 0905Z. OTHER PRECIP ECHOES WERE JUST
SOUTH OF THE INTERNATIONAL BORDER ADJACENT SWRN COCHISE/ERN SANTA
CRUZ COUNTIES. MESOSCALE CONVECTIVE SYSTEM DECAYING ACROSS NORTHERN
AND CENTRAL SONORA AT THIS TIME...WITH CLOUD TOPS GENERALLY WARMING
DURING THE PAST 2-3 HOURS. BASED ON RADAR TRENDS AS WELL AS THE
PROXIMITY OF THIS WEAKENING SYSTEM TO SE AZ...HAVE OPTED FOR
ISOLATED SHOWERS/TSTMS THIS MORNING ACROSS SWRN COCHISE COUNTY AND
MUCH OF SANTA CRUZ COUNTY. ISOLATED SHOWERS/TSTMS SHOULD ALSO
DEVELOP ACROSS THE WHITE MOUNTAINS OF NRN GREENLEE/GRAHAM COUNTIES
BY LATE MORNING AS PER SEVERAL RUC HRRR SOLUTIONS.
OTHERWISE...POPS WERE TRENDED UPWARD FOR THIS AFTERNOON AND THIS
EVENING BASED ON THE 14/00Z NAM/GFS/ECMWF SOLUTIONS. THUS...
SCATTERED SHOWERS/TSTMS ARE EXPECTED TO OCCUR THIS AFTERNOON AND
THIS EVENING FROM TUCSON EWD/SWD WITH LESSER CHANCES OF PRECIP NORTH
AND WEST OF TUCSON. FOR LATE TONIGHT...HAVE NOTED THAT THE GFS
CONTINUES THE POTENTIAL FOR AT LEAST ISOLATED SHOWERS/TSTMS ACROSS
MUCH OF THE AREA VERSUS THE NAM. FOR NOW HAVE LIMITED A SLIGHT
CHANCE OF SHOWERS/TSTMS LATE TONIGHT ACROSS COCHISE/SANTA CRUZ
COUNTIES WITH DRY CONDITIONS ELSEWHERE. HOWEVER...CONFIDENCE IS LOW
IN THIS SCENARIO.
THUR-SAT...
14/00Z GFS/ECMWF WERE SIMILAR WITH DEPICTING 594 DM HIGH TO BE
CENTERED OVER SE AZ THUR. UPPER RIDGE IS THEN PROGGED TO AMPLIFY
OVER THE SWRN CONUS/ROCKIES FRI-SAT. MOISTURE IS ALSO PROGGED TO
INCREASE ACROSS THIS FORECAST AREA. ALTHOUGH WARMER MID-LEVEL TEMPS
MAY LIMIT CONVECTIVE DEVELOPMENT SOMEWHAT...MOISTURE SHOULD STILL BE
SUFFICIENT TO JUSTIFY SCATTERED AFTERNOON AND EVENING SHOWERS/TSTMS
EAST AND SOUTH OF TUCSON. ISOLATED AFTERNOON AND EVENING SHOWERS/
TSTMS WILL PREVAIL FROM TUCSON WWD/NWWD.
SUN-TUE...
THERE CONTINUED TO BE DIFFERENCES BETWEEN THE GFS/ECMWF REGARDING
THE UPPER LEVEL PATTERN OVER THE WRN CONUS THIS PERIOD. THE ECMWF
DEPICTED THE UPPER HIGH TO FLATTEN SUN AS A SHORTWAVE TROUGH MOVES
NORTH OF THE AREA. UPPER HIGH IS THEN PROGGED TO AMPLIFY OVER THE
AREA MON-TUE. MEANWHILE...THE GFS MAINTAINED THE UPPER HIGH OVER
ARIZONA SUN-TUE AS THE CLOSED LOW INITIALLY NEAR THE NRN CALIFORNIA
COAST FILLS AND EJECTS NEWD INTO THE PACIFIC NW. THE UPSHOT FOR SE
AZ...MOISTURE SHOULD STILL BE SUFFICIENT FOR ISOLATED-SCATTERED
AFTERNOON AND EVENING SHOWERS/TSTMS MAINLY FROM TUCSON EWD/SWD EARLY
NEXT WEEK.
HIGH TEMPS TODAY-TUE WILL GENERALLY BE ABOUT 3-8 DEGS F ABOVE
NORMAL. THE FORECAST HIGH TEMP AT TUCSON INTERNATIONAL AIRPORT TODAY
OF 105 DEGS...IF ACHIEVED...WILL BE WITHIN ONE DEGREE OF THE RECORD
HIGH TEMP FOR THIS DATE (106 DEGS SET IN 2012...1994...AND 1988).
&&
.AVIATION...VALID THRU 15/12Z. SCT080-120 SCT-BKN300. ISOLD -SHRA
NEAR THE MEXICO BORDER THIS MORNING. THEN SCT TSRA DEVELOPING AFTER
14/17Z S AND E OF KCGZ WITH MVFR CONDITIONS AND STRONG OUTFLOW WINDS
NEAR STORMS. OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS
WITH NORMAL DIURNAL DIRECTION CHANGES. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THUNDERSTORMS JUST SOUTH OF THE BORDER WILL HELP TO
INCREASE MOISTURE ACROSS SE AZ TODAY WITH A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS NEAR THE INTERNATIONAL BORDER THIS MORNING AND A
GREATER THREAT OF SHOWERS AND THUNDERSTORMS ACROSS MOST OF THE AREA
THIS AFTERNOON AND EVENING. THE INCREASE IN MOISTURE WILL ALSO BOOST
THE RH VALUES A BIT...ESPECIALLY THE OVERNIGHT RECOVERIES. FROM
THURSDAY ONWARD...UPPER LEVEL HIGH PRESSURE WILL BE OVER THE REGION
BUT THERE WILL BE ENOUGH MOISTURE TO GENERATE ISOLATED TO SCT
AFTERNOON AND EVENING CONVECTION EACH DAY. OUTSIDE OF THUNDERSTORM
WINDS...NORMAL DIURNAL WIND TRENDS ARE EXPECTED THROUGH THE
WEEKEND...WITH OCCASIONAL GUSTS DURING THE MID TO LATE AFTERNOON
HOURS DUE TO STRONG DAYTIME HEATING.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
209 AM EDT WED AUG 14 2013
.UPDATE...
COLD FRONT CURRENTLY ACROSS NORTHERN GA THIS EVENING. A FEW
SHOWERS HAVE DEVELOPED BEHIND THE BOUNDARY...BUT THEY HAVE BEEN
SHORT LIVED. STORMS ARE MORE NUMEROUS SOUTH OF THE METRO
AREA...WHERE ACTIVITY KEEPS MOVING IN FROM EASTERN AL. THE ATMOS
ACROSS PORTIONS OF CENTRAL AND SOUTHERN GA WILL REMAIN UNSTABLE
FOR THE NEXT FEW HOURS. CONVECTION SEEMS TO MOSTLY BE OUTFLOW
DRIVEN. DO EXPECT STORMS TO DIMINISH WITH THE LOSS OF
HEATING AND MOSTLY BE GONE BY MIDNIGHT. THE HRRR SUPPORTS THIS.
MAY HAVE TO DO ADDITIONAL UPDATES TO THE POPS ACROSS NORTHERN
GA...MAINLY AREAS NORTH OF THE FRONT...LATER TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 325 PM EDT TUE AUG 13 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
SHORT RANGE MODELS CONTINUE TO SHOW A COLD FRONT...CURRENTLY ACROSS
TN... SAGGING ACROSS NORTH GA TONIGHT AND STALLING ACROSS CENTRAL GA
WEDNESDAY AFTERNOON. REGIONAL RADARS SHOW SCATTERED SHOWERS AND
THUNDERSTORMS BEGINNING TO DEVELOP ACROSS THE FORECAST AREA AS AN
UPPER DISTURBANCE APPROACHES FROM THE WEST. EXPECT A WEAK SURFACE
TROUGH TO HELP PROVIDE A FOCUS ACROSS NORTH GA THIS AFTERNOON AND
RADAR TRENDS SUPPORT THAT...WITH A SCATTERED LINE OF CONVECTION
DEVELOPING FROM WEST OF ROME...EASTWARD TO JASPER AND CLEVELAND.
EXPECT THIS ACTIVITY TO SAG SOUTHWARD THROUGH THE LATE AFTERNOON AND
EVENING HOURS. ADDITIONAL SCATTERED TO NUMEROUS CONVECTION IS
DEVELOPING ACROSS PARTS OF CENTRAL GA WHERE THE GREATER
INSTABILITIES AND DEEPER MOISTURE ARE POOLED. THE HRRR MODEL
CLUSTERS MOST OF THE CONVECTIVE ACTIVITY ACROSS THE CENTRAL ZONES...
FROM AREAS AROUND COLUMBUS TO MACON TO MILLEDGEVILLE AND SOUTHWARD
DURING THE LATE AFTERNOON AND EVENING HOURS. THUNDERSTORM ACTIVITY
MAY PERSIST THROUGH MID EVENING BEFORE DIMINISHING TO MAINLY
SHOWERS. SCATTERED SHOWERS MAY PERSIST OVERNIGHT ALONG AND AHEAD OF
THE COLD FRONT... BUT ANY THUNDERSTORM ACTIVITY SHOULD BE VERY
ISOLATED AT BEST OVERNIGHT. THE MAIN THUNDERSTORM THREAT THROUGH THE
EVENING WILL CONTINUE TO BE LOCALLY HEAVY RAIN AND POSSIBLE BRIEF
FLOODING. HOWEVER... WITH 2500-3000 CAPE... CANNOT RULE OUT A PULSE
STRONG STORM PRODUCING WIND GUSTS TO 40-45 MPH AND POSSIBLY SOME
SMALL HAIL. MODELS AGREE ON DRIER AIR SPREADING IN BEHIND THE FRONT
ACROSS NORTH GA BY EARLY WEDNESDAY... SO WILL SHOW THE GREATER RAIN
CHANCES ACROSS CENTRAL GA ON WEDNESDAY...AND MAINLY ALONG AND SOUTH
OF A LA GRANGE TO WARRENTON LINE...WITH ONLY A LOW CHANCE IN THE
ATLANTA METRO AREA FOR WEDNESDAY AFTERNOON. LOCALLY HEAVY RAIN WILL
REMAIN A THREAT ACROSS CENTRAL GA WEDNESDAY AFTERNOON AS THE FRONT
PROVIDES A FOCUS FOR TRAINING CONVECTION. MODELS SHOW GENERALLY ONE
QUARTER TO ONE HALF INCH FROM COLUMBUS TO MACON AND SOUTHWARD ON
WEDNESDAY... BUT ISOLATED HIGHER AMOUNTS OF 1 TO 3 INCHES ARE
POSSIBLE. ALTHOUGH CANNOT RULE OUT A PULSE STRONG TO SEVERE STORM
ALONG OR SOUTH OF THE FRONT WEDNESDAY AFTERNOON... NOT EXPECTING
ANYTHING WIDESPREAD AND THE GREATER STRONG STORM THREAT SHOULD BE
JUST SOUTH OF THE FORECAST AREA WEDNESDAY AFTERNOON AND EVENING.
OTHERWISE... AS FOR TEMPS A MODEL BLEND THROUGH THE SHORT TERM
LOOKED REASONABLE.
39
LONG TERM /THURSDAY THROUGH TUESDAY/...
GUIDANCE CONTINUES TO POINT TO A WET EXTENDED PERIOD. AS THE FRONT
SAGS SOUTH OF THE AREA TROUGH THE SHORT TERM...SURFACE HIGH UNDER
CONFLUENT FLOW ALOFT WILL SLIP EAST AND ACROSS THE APPALACHIANS IN
A HYBRID DAMMING EVENT. THE QUESTION WILL BE HOW MUCH GULF
MOISTURE WILL INTERACT WITH THE DAMMING. FOR THURSDAY...WITH THE
STALLED FRONT AND ONSET OF HYBRID CAD...HPC AND SYNOPTIC MODELS
KEEP THE BEST PRECIP ACROSS CENTRAL GEORGIA...WITH A GOOD INCH OF
BASIN-AVERAGE QPF DURING THE DAY. THIS TREND CONTINUES INTO
FRIDAY. BESIDES THE PRECIP HOWEVER...THE BIGGEST SENSIBLE IMPACT
WILL BE TEMPS. CURRENT HIGH TEMPS FOR THURSDAY THROUGH SATURDAY DO
NOT BRING NORTH GEORGIA OUT OF THE 70S...AND REALLY ONLY INTO THE
MID 80S IN SOUTHERN ZONES. POSSIBLY A SLIGHT WARMING TREND BY A
DEGREE OR SO ON SUNDAY BUT THIS REMAINS TO BE SEEN. THESE FORECAST
MAX TEMPS ARE A GOOD 10 DEGREES COOLER THAN SEASONAL NORMALS...
THE KIND OF IMPACTS NORMALLY SEEN WITH CLASSICAL CAD RATHER THAN
HYBRID CAD.
00Z ECMWF CONTINUES TO TAKE THE TROPICAL WAVE /CURRENTLY IN THE
CARIBBEAN/ FURTHER WEST TOWARD THE YUCATAN...WHILE GFS AND
CANADIAN BRING IT INTO THE GULF AND CLOSE TO THE COAST FRIDAY
NIGHT. FOR WHAT ITS WORTH...THE CANADIAN IS STRONGER AND FURTHER
WEST WITH THE SURFACE LOW THAN THE GFS...WHICH WOULD POSSIBLY
INDICATE SEVERE POTENTIAL ON SATURDAY...BUT IT IS A BIT OF AN
OUTLIER THERE. ECMWF IS DRIEST WHILE GFS/CMC ARE WETTER
SOLUTIONS. HPC NOT GOING NEARLY AS HIGH AS THE GFS BUT EVEN
SO...WITH THE PROLONGED WET PERIOD ACROSS ESPECIALLY CENTRAL
GEORGIA FROM THE SHORT TERM FRONT...THERE IS SOME CONCERN ABOUT
THE RAINFALL PILING UP. HAVE NOT DONE A COMPLETE DIAGNOSIS TO
DETERMINE IF THE THURSDAY-FRIDAY RAIN WOULD QUALIFY AS A PRE
/PREDECESSOR RAINFALL EVENT/ BUT IN ANY CASE THE 7-DAY QPF TOTAL
FROM HPC ARE UPWARDS OF 6 INCHES ACROSS PORTIONS OF CENTRAL
GEORGIA. THIS BEING BASIN-AVERAGE...IMPLYING THAT SOME AREAS
COULD GET SUBSTANTIALLY MORE /AND OF COURSE SOME AREAS
SUBSTANTIALLY LESS/. ALL INTERESTS SHOULD STAY TUNED TO LATEST
FORECASTS AS THIS IS REFINED OVER THE NEXT FEW DAYS.
SO OVERALL...REALLY MADE ONLY MINOR CHANGES TO PREVIOUS EXTENDED
FORECAST. REFINED AND ADDED SOME DETAIL TO DAYS 4 AND 5 ESPECIALLY
WITH TEMPS WINDS AND DEWPOINTS /VERY LITTLE IF ANY CHANGE TO
POPS/ AND MADE SOME MINOR ADJUSTMENTS TO HIGH TEMPS THROUGH THE
REST OF THE PERIOD TO REFLECT THE PROLONGED COOL SPELL.
TDP
&&
.AVIATION...
06Z UPDATE...
A WEAK COLD FRONT CONTINUES TO SLOWLY MOVE INTO THE NORTH SIDE OF
THE ATLANTA METRO AREA AT THIS TIME. IFR CIGS SHOWING UP IN AREAS
THAT HAD RAIN ON TUESDAY...OTHERWISE GENERALLY VFR CIGS ARE
EXPECTED...BUT WILL MONITOR CLOSELY AROUND SUNRISE. THE RAP13 MODEL
INDICATES THE FRONT WILL CONTINUE MOVING SOUTH TODAY...BUT WILL
LIKELY STALL OUT JUST SOUTH OF CSG AND MCN. SCATTERED TSTMS EXPECTED
AROUND THE FRONTAL ZONE THIS AFTERNOON AND EARLY EVENING...THIS
WOULD BE BASICALLY ATL-AHN SOUTHWARD. A LIGHT W-NW WIND THIS MORNING
SHIFTING TO NE AFTER FRONTAL PASSAGE.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON ALL ELEMENTS.
16
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 69 88 68 78 / 30 40 20 30
ATLANTA 70 86 69 79 / 30 30 20 50
BLAIRSVILLE 64 81 64 76 / 20 20 20 30
CARTERSVILLE 68 86 64 82 / 20 20 20 30
COLUMBUS 73 87 71 84 / 30 60 40 80
GAINESVILLE 69 85 68 76 / 20 20 20 30
MACON 72 89 71 82 / 40 60 50 80
ROME 68 89 63 83 / 20 20 10 30
PEACHTREE CITY 70 86 66 79 / 30 40 20 50
VIDALIA 74 88 71 84 / 50 60 60 80
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1125 PM CDT Tue Aug 13 2013
.SHORT TERM...(This Evening through Wednesday)
Issued at 328 PM CDT TUE AUG 13 2013
Upper trough remains over the Great Lakes with a shortwave trough
extending southwestward into eastern Nebraska. This shortwave along
with a well defined MCV in southern Nebraska helped sustain a
cluster of showers and thunderstorms into the far northwest corner
of the CWA this afternoon. However...a drier and more stable
atmosphere over most of the CWA has aided a weakening trend to the
convection and expect any sustained or additional development to
occur in the western or far southern CWA until early evening. At
that time...feel majority of convection...now occurring in central
KS will have advanced further south of the vicinity with the outflow
boundary...similar to the HRRR model. Will therefore carry a dry
forecast for the overnight. Skies may become mostly clear tonight which
would support the possibility of some patchy fog. However...feel the
potential for more high clouds to advance into the area from the
northwest is high enough to negate mentioning fog for now. The dry
air and breaks in the clouds should help lows fall into the lower
60s.
On Wednesday...will maintain a dry forecast as the deeper moisture and
axis of higher instability are pushed more to the west of the CWA.
Any convection through the day should remain to the west and north
of the CWA. High temperatures Wednesday will be similar
today...except slightly warmer in the north central with readings
in the lower 80s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 328 PM CDT TUE AUG 13 2013
For Wednesday night through Friday, the models have trended more
along the lines of the NAM with keeping much of the cooler and
dryer air to the northeast of the forecast area. On top of that
instead of a distinct shortwave trough moving through the
northwest flow Thursday night, models have trended towards
bringing several vort maximum through the flow late Wednesday
night through Friday. Because of this have trended min temps
warmer expecting more cloud cover and higher dewpoint temps
through the night. Will also carry a 20 to 30 percent chance pops
through the period. Forecast soundings with the higher dewpoints
show much less inhibition to convection with lower LCL heights.
because of this it is difficult to rule out precip chances with
the expected vort energy moving overhead. The airmass in general
does not change much from today. Therefore expect temps to be
relatively persistent with highs around 80 and lows in the lower
to mid 60s.
Saturday into Monday is expected to be dry with a gradual warming
trend as mid level ridging moves in from the west and insolation
increases. Uncertainty remains in the forecast for next week as
the ECMWF has shown little consistency from run to run over the
last 48 hrs. Think that there will be a small chance for precip
Monday night and Tuesday as the GFS continues to bring a shortwave
trough across the plains. However confidence is not high since the
ECMWF goes back and forth between cutting off an upper low and an
open shortwave.
&&
.AVIATION...(For the 06Z TAFs through 06Z Wednesday Night)
Issued at 1123 PM CDT TUE AUG 13 2013
High clouds clearing over western areas at this writing with next
batch of high clouds still in northern Nebraska. Will therefore
add some MVFR visby restrictions to TOP and MHK. Winds turn to the
SE tomorrow and added a group for ending of BR to account for
this.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...63
LONG TERM...Wolters
AVIATION...67
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
525 AM EDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT WED AUG 14 2013
DRY HIGH PRESSURE WILL CONTINUE TO BE THE MAIN STORY TODAY. NW WINDS
WILL BE THE RULE...KEEPING LOCATIONS NEAR LAKE SUPERIOR IN THE 60S
FOR HIGH TEMPS WHILE REACHING INTO THE LOWER 70S INLAND.
A THIN RIBBON OF CLOUDS ACROSS S ONTARIO AND N LAKE SUPERIOR WILL
CONTINUE TO SHIFT SSE AND EXPAND OVER LAKE SUPERIOR THIS
MORNING...AND PUSH OVER CENTRAL AND E UPPER MI THROUGH THE DAY
TODAY. THIS BAND HAS BEEN PICKED UP BY ONLY A FEW MODELS...NAMELY
THE RUC AND CANADIAN...AND TO A LESSER EXTENT THE NAM. WILL LEVERAGE
THEM MORE ON THE CLOUD FCST THROUGH THE DAY TODAY GIVEN THEIR BETTER
INITIAL PROGNOSIS.
ANOTHER MOSTLY CLEAR NIGHT IS IN STORE FOR US. HOWEVER...TEMPS
SHOULD BOTTOM OUT AROUND 5F WARMER THAN THIS MORNING. WILL KEEP ANY
MENTION OF FROST OUT OF THE FCST WITH THE LOWEST READINGS EXPECTED
AT THIS TIME BEING RIGHT AROUND 40F INLAND FROM THE GREAT LAKES.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 451 AM EDT WED AUG 14 2013
THU AND THU NIGHT...NW MID/UPPER LEVEL FLOW THROUGH THE NRN GREAT LAKES
WILL PREVAIL BETWEEN A TROUGH OVER QUEBEC AND A RIDGE FROM THE SW
CONUS INTO CNTRL CANADA. WITH THE DRY AIRMASS REMAINING OVER THE
REGION...ANY WEAK SHORTWAVES WILL NOT PRODUCE ANY PCPN. INCEASING
WAA AS THE SFC HIGH SHIFTS TOWARD THE SRN GREAT LAKES WILL PUSH 850
MB TEMPS INTO THE 10C-12C ALLOWING HIGHS TO CLIMB BACK INTO THE MID
AND UPPER 70S. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
DROP BACK TO AROUND 50.
FRI...ALTHOUGH LOW LEVEL MOISTURE TRANSPORT BACK INTO THE REGION
WILL BE MODEST...EXPECT ENOUGH OF AN INCREASE FOR DEWPOINTS TO CLIMB
INTO THE LOWER TO MID 50S. THE NAM/GFS/UKMET SUGGEST THAT SOME PCPN
MAY BE POSSIBLE...ESPECIALY DURING PEAK HEATING WITH MLCAPE VALUES
CLIMBING INTO THE 400-800 J/KG RANGE. HOWEVER...THE MODELS MAY ALSO
BE TOO AGGRESSIVE WITH THE AMOUNT OF MOISTURE AVAILABLE MAKING THE
INVERSION/CAPPING AROUND 700 MB MORE DIFFICULT TO OVERCOME.
SO...ONLY ADDED SLIGHT CHANCE WORDING FOR SHRA/TSRA FOR INLAND WEST
LOCATIONS WITH POPS REMAINING AOB 20 PCT.
SAT...THE MID LEVEL RIDGE WILL BUILD INTO THE AREA...BOOSTING THE
CAPPING AND REDUCING ANY PCPN CHANCES EVEN THOUGH LOW LEVEL MOISTURE
WILL ALSO INCREASE. TEMPERATURES WILL REMAIN ABOVE AVERAGE WITH
HIGHS INTH THE UPPER 70S.
SUN-TUE...THE GFS/GEM/UKMET SUGGEST THAT A SHORTWAVE TROUGH MAY MOVE
INTO THE NRN GREAT LAKES MON INTO MON NIGHT BRINGING SHRA/TSRA POTENTIAL
WHILE THE ECMWF WIH A MORE ZONAL PATTERN KEEPS A WEAKER SHRTWV
FARTHERN N THROUGH NRN ONTARIO. GIVEN MODEL DIFFERENCES...FCST
REMAINS IN LIE WITH MDLS CONSENSUS SLIGHT CHANCE POPS. TEMPERATURES
WILL REMAIN ABOVE NORMAL WITH HIGHS FROM THE UPPER 70S TO THE LOWER
80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 524 AM EDT WED AUG 14 2013
WHILE A FEW CLOUDS WILL PASS FROM TIME TO TIME...THEY SHOULD REMAIN
VFR...WITH DIURNAL WINDS NEARING 10KTS DURING THE DAYTIME HOURS
TODAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 AM EDT WED AUG 14 2013
A RIDGE OF HIGH PRESSURE SHOULD BE THE RULE THROUGH THE UPCOMING
WEEKEND...RESULTING IN RELATIVLY LIGHT WINDS. LARGE HIGH PRESSURE
STRETCHING FROM SOUTH CENTRAL CANADA THROUGH THE UPPER GREAT LAKES
AND MID MISSISSIPPI VALLEY WILL SLOWLY SINK ACROSS THE OHIO VALLEY
AND MID ATLANTIC STATES ON THURSDAY. THE EVER-PRESENT AREA OF HIGH
PRESSURE WILL THEN EXPAND NORTHWARD TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES ON THURSDAY NIGHT THROUGH SUNDAY. EXPECT A TROUGH TO
SET UP OVER THE NORTHERN PLAINS INTO MANITOBA ON SUNDAY...WITH WIND
GUSTS STILL AROUND 20KTS OR LESS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...JLB
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
510 AM EDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT WED AUG 14 2013
DRY HIGH PRESSURE WILL CONTINUE TO BE THE MAIN STORY TODAY. NW WINDS
WILL BE THE RULE...KEEPING LOCATIONS NEAR LAKE SUPERIOR IN THE 60S
FOR HIGH TEMPS WHILE REACHING INTO THE LOWER 70S INLAND.
A THIN RIBBON OF CLOUDS ACROSS S ONTARIO AND N LAKE SUPERIOR WILL
CONTINUE TO SHIFT SSE AND EXPAND OVER LAKE SUPERIOR THIS
MORNING...AND PUSH OVER CENTRAL AND E UPPER MI THROUGH THE DAY
TODAY. THIS BAND HAS BEEN PICKED UP BY ONLY A FEW MODELS...NAMELY
THE RUC AND CANADIAN...AND TO A LESSER EXTENT THE NAM. WILL LEVERAGE
THEM MORE ON THE CLOUD FCST THROUGH THE DAY TODAY GIVEN THEIR BETTER
INITIAL PROGNOSIS.
ANOTHER MOSTLY CLEAR NIGHT IS IN STORE FOR US. HOWEVER...TEMPS
SHOULD BOTTOM OUT AROUND 5F WARMER THAN THIS MORNING. WILL KEEP ANY
MENTION OF FROST OUT OF THE FCST WITH THE LOWEST READINGS EXPECTED
AT THIS TIME BEING RIGHT AROUND 40F INLAND FROM THE GREAT LAKES.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 451 AM EDT WED AUG 14 2013
THU AND THU NIGHT...NW MID/UPPER LEVEL FLOW THROUGH THE NRN GREAT LAKES
WILL PREVAIL BETWEEN A TROUGH OVER QUEBEC AND A RIDGE FROM THE SW
CONUS INTO CNTRL CANADA. WITH THE DRY AIRMASS REMAINING OVER THE
REGION...ANY WEAK SHORTWAVES WILL NOT PRODUCE ANY PCPN. INCEASING
WAA AS THE SFC HIGH SHIFTS TOWARD THE SRN GREAT LAKES WILL PUSH 850
MB TEMPS INTO THE 10C-12C ALLOWING HIGHS TO CLIMB BACK INTO THE MID
AND UPPER 70S. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
DROP BACK TO AROUND 50.
FRI...ALTHOUGH LOW LEVEL MOISTURE TRANSPORT BACK INTO THE REGION
WILL BE MODEST...EXPECT ENOUGH OF AN INCREASE FOR DEWPOINTS TO CLIMB
INTO THE LOWER TO MID 50S. THE NAM/GFS/UKMET SUGGEST THAT SOME PCPN
MAY BE POSSIBLE...ESPECIALY DURING PEAK HEATING WITH MLCAPE VALUES
CLIMBING INTO THE 400-800 J/KG RANGE. HOWEVER...THE MODELS MAY ALSO
BE TOO AGGRESSIVE WITH THE AMOUNT OF MOISTURE AVAILABLE MAKING THE
INVERSION/CAPPING AROUND 700 MB MORE DIFFICULT TO OVERCOME.
SO...ONLY ADDED SLIGHT CHANCE WORDING FOR SHRA/TSRA FOR INLAND WEST
LOCATIONS WITH POPS REMAINING AOB 20 PCT.
SAT...THE MID LEVEL RIDGE WILL BUILD INTO THE AREA...BOOSTING THE
CAPPING AND REDUCING ANY PCPN CHANCES EVEN THOUGH LOW LEVEL MOISTURE
WILL ALSO INCREASE. TEMPERATURES WILL REMAIN ABOVE AVERAGE WITH
HIGHS INTH THE UPPER 70S.
SUN-TUE...THE GFS/GEM/UKMET SUGGEST THAT A SHORTWAVE TROUGH MAY MOVE
INTO THE NRN GREAT LAKES MON INTO MON NIGHT BRINGING SHRA/TSRA POTENTIAL
WHILE THE ECMWF WIH A MORE ZONAL PATTERN KEEPS A WEAKER SHRTWV
FARTHERN N THROUGH NRN ONTARIO. GIVEN MODEL DIFFERENCES...FCST
REMAINS IN LIE WITH MDLS CONSENSUS SLIGHT CHANCE POPS. TEMPERATURES
WILL REMAIN ABOVE NORMAL WITH HIGHS FROM THE UPPER 70S TO THE LOWER
80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1206 AM EDT WED AUG 14 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT CMX AND SAW. AT
IWD SOME BR IS BRINGING VIS DOWN...WHICH SHOULD LAST INTO THE REST
OF TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 AM EDT WED AUG 14 2013
A RIDGE OF HIGH PRESSURE SHOULD BE THE RULE THROUGH THE UPCOMING
WEEKEND...RESULTING IN RELATIVLY LIGHT WINDS. LARGE HIGH PRESSURE
STRETCHING FROM SOUTH CENTRAL CANADA THROUGH THE UPPER GREAT LAKES
AND MID MISSISSIPPI VALLEY WILL SLOWLY SINK ACROSS THE OHIO VALLEY
AND MID ATLANTIC STATES ON THURSDAY. THE EVER-PRESENT AREA OF HIGH
PRESSURE WILL THEN EXPAND NORTHWARD TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES ON THURSDAY NIGHT THROUGH SUNDAY. EXPECT A TROUGH TO
SET UP OVER THE NORTHERN PLAINS INTO MANITOBA ON SUNDAY...WITH WIND
GUSTS STILL AROUND 20KTS OR LESS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...JLB
AVIATION...TITUS
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
324 AM EDT WED AUG 14 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 324 AM EDT WED AUG 14 2013
TODAY WILL BE THE COLDEST DAY FOR AT LEAST THE NEXT WEEK OR TWO.
DESPITE SUNSHINE TEMPERATURES WILL CLIMB TO AROUND 70. A WARM UP
WILL BEGIN THURSDAY AS TEMPERATURES CLIMB THROUGH THE 70S AND INTO
THE 80S BY THE WEEKEND. DRY WEATHER IS EXPECTED THROUGH THE WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 324 AM EDT WED AUG 14 2013
FORECAST CONCERNS ARE MINIMAL THIS MORNING.
HIGH PRESSURE AT THE SFC COUPLED WITH TROUGHING ALOFT WILL LIKELY
CREATE SEVERAL DAYS OF DIURNALLY DRIVEN CU FOLLOWED BY MOSTLY CLEAR
SKIES THROUGH FRIDAY.
SFC ANALYSIS SHOWS HIGH PRESSURE OVER WISCONSIN. THIS HIGH WILL
CONTINUE TO MOVE TOWARD LOWER MICHIGAN DURING THE NEXT FEW DAYS.
LATEST IR LOOP SHOWS THE LAST OF THE STRATOCU COVERING THE THUMB AND
CLEAR SKIES OVER THE CWA.
WE SHOULD SEE PARTLY CLOUDY SKIES TODAY WITH QUITE A BIT OF SUNSHINE
THIS MORNING AND CU THIS AFTERNOON GIVEN THE COOLER TEMPS ALOFT
ASSOCIATED WITH THE UPPER TROUGH. AS THE DEEP UPPER TROUGH MOVES
NEWD THE CORE OF THE COLD AIR ALOFT WILL GO WITH IT AND TEMPS WILL
BEGIN TO RISE. LOOK FOR A WARMING TREND THROUGH FRIDAY AS HIGHS
REBOUND TO THE MID 70S...WHICH WILL STILL BE A FEW DEGREES BELOW
NORMAL. GIVEN THE DRY AIRMASS...RAIN IS NOT EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM EDT WED AUG 14 2013
OVERALL THE TREND OF THE MODELS SUPPORTS WARMER TEMPERATURES FOR THE
EARLY TO MIDDLE PART OF NEXT WEEK. I BUMPED UP TEMPERATURES A FEW
DEGREES AS A RESULT. WITH THE HIGH PRESSURE SYSTEM TRACKING
SOUTHWARD FROM NEW ENGLAND DOWN TO THE CAROLINAS SUNDAY INTO
TUESDAY...THIS SUPPORTS A PERIOD OF WARM AIR ADVECTION FOR THE GREAT
LAKES REGION. TEMPS AT 850 MB RISE INTO THE TEENS. THIS SHOULD
SUPPORT DAYTIME SURFACE TEMPS INTO THE 80S.
AS FOR PRECIPITATION...THIS RELATIVELY WESTWARD SETUP OF THE HIGH
PRESSURE SYSTEM...AS OPPOSED TO A BERMUDA HIGH...MEANS THE MAIN AXIS
OF GULF MOISTURE ADVECTS NORTHWARD THROUGH THE WESTERN PLAINS. SO
IT APPEARS THAT THE ARRIVAL OF THIS DEEPER MOISTURE INTO THE GREAT
LAKES REGION...WILL BE DELAYED UNTIL MAYBE THE THE MIDDLE OF NEXT
WEEK. AS A RESULT I KEPT POPS LOW FOR THIS FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1205 AM EDT WED AUG 14 2013
CLEAR SKIES AND LIGHT NORTH TO NORTHWEST WINDS ARE EXPECTED DURING
THE EARLY MORNING HOURS OF WEDNESDAY AS A LARGE CANADIAN ORIGIN
HIGH MOVES ACROSS LOWER MICHIGAN. THE HRRR DID A VERY GOOD JOB
THIS EVENING OF SHOWING THE CLOUDS DISSIPATING IN THE 01-03Z TIME
FRAME. THE COLD AIR STRATOCUMULUS CLOUDS SHOULD STAY OVER LAKE
HURON. WEDNESDAY SHOULD BE A SUNNY DAY BUT MODEL SOUNDING SUGGEST
SOME HIGH BASED CU DURING THE LATE MORNING AND EARLY AFTERNOON.
&&
.MARINE...
ISSUED AT 324 AM EDT WED AUG 14 2013
BOTH THE BHS AND SCA HAVE EXPIRED. WIND SPEEDS AND WAVE HEIGHTS WILL
CONTINUE TO DECREASE TODAY. INITIALLY THOUGH THIS MORNING THERE
COULD BE SOME WAVE HEIGHTS AROUND 3 FEET BEFORE THEY DECREASE LATER
IN THE DAY.
&&
.HYDROLOGY...
ISSUED AT 324 AM EDT WED AUG 14 2013
NO HYDRO CONCERNS. RIVER LEVELS WILL SLOWLY FALL THROUGH THE WEEKEND
WITH NO RAIN EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1205 AM EDT WED AUG 14 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 306 PM EDT TUE AUG 13 2013
A WAVE OF LOW PRESSURE MOVING THROUGH THE AREA THIS AFTERNOON WILL
MOVE EAST OF THE AREA THIS EVENING. CLOUDS WILL GRADUALLY DIMINISH
THIS EVENING. HIGH PRESSURE WILL THEN BUILD INTO THE AREA BEGINNING
ON WEDNESDAY AND LASTING INTO THE WEEKEND. THIS WILL BRING DRY
WEATHER TO THE AREA. TEMPERATURES WILL START OUT COOL AND GRADUALLY
WARM THROUGH THE PERIOD.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 306 PM EDT TUE AUG 13 2013
THE ONLY WEATHER OF NOTE IN THE SHORT TERM IS FROM THIS AFTERNOON
INTO EARLY THIS EVENING WHEN THERE IS A CHANCE OF SPRINKLES UP NORTH
OR CHANCE OF A LIGHT SHOWER ALONG THE LAKESHORE. OTHER THAN
THAT...DRY AND COOL WEATHER CAN BE EXPECTED THROUGH THE REMAINDER OF
THE SHORT TERM.
THE GOING FORECAST IS ON TRACK THIS AFTERNOON WITH VERY LITTLE IF
ANY PCPN CURRENTLY BEING REPORTED. KGRR RADAR IN CLEAR AIR MODE IS
PICKING UP ON THE FLAT CU/STRATOCU PRESENT THIS AFTERNOON. NO RAIN
HAS BEEN REPORTED AT ANY STATION IN THE CWFA THUS FAR. THE SHORT
WAVE IS NOW ENTERING THE NRN SECTION OF THE CWFA...SO THIS WOULD BE
THE BEST CHC RIGHT NOW. FCST SOUNDINGS CONTINUE TO INDICATE AN
INVERSION AROUND 700 MB THAT IS PREVENTING SUFFICIENT VERTICAL
GROWTH OF THE CU FIELD. DRY AIR AT THE SFC ALSO IS LIMITING THE
GROWTH.
THE MID LEVEL TEMPERATURES WILL SLOWLY MODIFY THIS EVENING AS THE
SHORT WAVE MOVES EAST. WE WILL LOSE THE DIURNAL COMPONENT ALSO WHICH
WILL ONLY STRENGTHEN THE CAUSE FOR DRY CONDITIONS. OVER LAKE
INSTABILITY WILL REMAIN IN THE LOW TO MID TEENS...BUT THE 700 MB
INVERSION WILL EVEN LIMIT LAKE MODIFIED PARCELS. THIS WILL ALSO SHUT
DOWN THE LOW CHC OF WATERSPOUTS OVER THE LAKE. WINDS WILL DROP OFF
AND THEN TEMPS WILL RESPOND WITH THE DRY AIR IN PLACE. MOST
LOCATIONS SHOULD DROP DOWN INTO THE 40S...WITH NEAR 40 UP NORTH.
THE REMAINDER OF THE SHORT TERM FROM WED THROUGH THU NIGHT WILL THEN
REMAIN QUIET. THE LONG WAVE TROUGH WILL REMAIN ENTRENCHED OVER THE
AREA. THE UPPER JET WILL LIFT NORTHEAST PUTTING THE AREA UNDER THE
ANTI-CYCLONIC SIDE OF THE JET. HIGH PRESSURE AT THE SFC WILL THEN
RULE. H850 TEMPS WILL SLOWLY MODIFY FROM THE SINGLE DIGITS C
WED...TO THE LOWER TEENS BY THU NIGHT. THIS WILL ALLOW SFC TEMPS TO
MODIFY EACH DAY WITH A GOOD DEAL OF SUNSHINE. NIGHT TIME LOWS WILL
SLOWLY MODIFY ALSO. LIMITED DIURNAL CU IS EXPECTED.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 306 PM EDT TUE AUG 13 2013
WE WILL STILL BE UNDER THE REGIME OF COOL AIR ALOFT WITH THE
NORTHWEST FLOW THROUGH FRIDAY. THIS WILL CONTINUE TO PRODUCE
DIURNAL CU AND A POSSIBLE ISOLATED DAYTIME SHOWER ACROSS THE
NORTHERN CWA. HOWEVER THE NORTHWEST FLOW BECOMES MORE ZONAL AND
GRADUAL WARMING ALOFT AND AT THE SURFACE IS EXPECTED INTO THE
WEEKEND...MAKING FOR SUNNIER DAYS. UPPER RIDGING BEGINS TO MOVE
OVER THE REGION BY SUNDAY WHEN WE SHOULD FINALLY SEE NEAR TO
SLIGHTLY ABOVE NORMAL TEMPS.
MUCH OF THE LONG TERM PERIOD LOOKS DRY...ALTHOUGH THERE IS A TREND
TO BREAK DOWN THE RIDGE INTO THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1205 AM EDT WED AUG 14 2013
CLEAR SKIES AND LIGHT NORTH TO NORTHWEST WINDS ARE EXPECTED DURING
THE EARLY MORNING HOURS OF WEDNESDAY AS A LARGE CANADIAN ORIGAIN
HIGH MOVES ACROSS LOWER MICHIGAN. THE HRRR DID A VERY GOOD JOB
THIS EVENING OF SHOWING THE CLOUDS DISSIPATING IN THE 01-03Z TIME
FRAME. THE COLD AIR STRATOCUMULUS CLOUDS SHOULD STAY OVER LAKE
HURON. WEDNESDAY SHOULD BE A SUNNY DAY BUT MODEL SOUNDING SUGGEST
SOME HIGH BASED CU DURING THE LATE MORNING AND EARLY AFTERNOON.
&&
.MARINE...
ISSUED AT 306 PM EDT TUE AUG 13 2013
WE WILL BE LEAVING THE MARINE HEADLINES UP AS THE WINDS CONTINUE TO
BE RATHER BREEZY. THE BUOYS ARE SHOWING ELEVATED WAVES...HOWEVER THE
HIGHEST WAVES ARE LIKELY MORE OFFSHORE PER THE FLOW AND MID LAKE
BUOY. THE WINDS AND WAVES WILL COME DOWN TONIGHT. WATERSPOUT CHANCES
WILL DIMINISH ENOUGH THIS EVENING TO KEEP THE MENTION OUT AFTER THIS
AFTERNOON.
AFTER TONIGHT...NO SIGNIFICANT WINDS OR WAVES ARE THEN EXPECTED
THROUGH THE NEXT WEEK WITH A RELATIVELY WEAK GRADIENT EXPECTED TO BE
IN PLACE.
&&
.HYDROLOGY...
ISSUED AT 306 PM EDT TUE AUG 13 2013
NO HYDROLOGY ISSUES ARE EXPECTED THROUGH AT LEAST THE NEXT WEEK.
RIVERS AND STREAMS ARE RUNNING A BIT HIGH ACROSS THE SRN TWO ROWS OF
COUNTIES FROM THE HEAVIER RAINFALL THAT FELL YESTERDAY. THE LEVELS
HAVE PRETTY MUCH STABILIZED AND THE STREAMS ARE NOW COMING DOWN.
VERY LITTLE IF ANY ADDITIONAL RAINFALL OVER THE NEXT WEEK WILL ALLOW
LEVELS TO RECOVER BACK CLOSER TO NORMAL DOWN SOUTH...AND REMAIN
BELOW NORMAL UP NORTH WHERE VERY LITTLE RAINFALL HAS FALLEN RECENTLY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
LMZ844>849.
&&
$$
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...JK
AVIATION...WDM
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
336 AM CDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 336 AM CDT WED AUG 14 2013
AS HAS BEEN THE CASE FOR THE LAST FEW WEEKS...EARLY MORNING WATER
VAPOR IMAGERY AND 500MB HEIGHTS AND WINDS IDENTIFIED A RIDGE ACROSS
THE EASTERN SPINE OF THE CANADIAN ROCKIES...WITH A LONGWAVE TROUGH
OVER THE GREAT LAKES AND EASTERN CANADA. NORTHWEST FLOW PERSISTED
OVER THE UPPER MIDWEST...WITH A COUPLE EMBEDDED SHORTWAVES OVER THE
HIGH PLAINS. ONE OF THESE SHORTWAVES WAS THE DRIVING FORCE BEHIND AN
MCS TRACKING EASTWARD ALONG THE NE/SD BORDER. HIRES MODELS SUCH AS THE
HOPWRF AND HRRR TAKE THIS CONVECTION DOWN THE MISSOURI RIVER VALLEY
THIS MORNING AND KEEPS MN/WI FREE FROM ANY PRECIP. THIS SOLUTION
MAKES SENSE GIVEN THE SUBSIDENCE BENEATH THE NORTHWEST FLOW IN
ASSOCIATION WITH NEGATIVE VORTICITY ADVECTION THAT IS FORECAST TO
MOVE ACROSS THE REGION THIS AFTERNOON. THEREFORE EXPECT ANOTHER DAY
OF LIGHT WINDS AND A FEW AFTERNOON CLOUDS WITH BASES AROUND 6000FT.
TEMPERATURES WILL BE SIMILAR TO YESTERDAY...BUT THE THIN CIRRUS FROM
THE CONVECTION OUT WEST MAY KEEP THEM A DEGREE OR TWO COOLER THAN
TUESDAYS HIGHS...ESPECIALLY IN WESTERN MN.
LATER TONIGHT ANOTHER SHORTWAVE IS FORECAST TO MOVE ACROSS THE
MISSOURI RIVER VALLEY...AND THIS WILL PRODUCE ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...WITH DEVELOPMENT EXPECTED A LITTLE
FARTHER EAST. THEREFORE EXPECT WESTERN MN TO BE DRY FOR MOST OF THE
PERIOD...BUT DID INTRODUCE A SLIGHT CHANCE OF POPS ACROSS THE
SOUTHWEST EARLY THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 336 AM CDT WED AUG 14 2013
THE WEAK MCS FROM WEDNESDAY NIGHT WILL BE LOCATED OVER WESTERN IA
AT THE BEGINNING OF THE PERIOD. EXTENSIVE CLOUDINESS AND POSSIBLE
RAIN ACROSS IA WILL KEEP TEMPERATURES COOL THERE...WHILE MORNING
SUNSHINE SHOULD ALLOW FOR A QUICK REBOUND BACK INTO THE 70S ACROSS
MN/WI. SYNOPTIC SOUTHERLY FLOW WILL ADVECT THE COOL BOUNDARY
NORTHWARD BY AFTERNOON...WHICH COULD PRODUCE A COUPLE SHOWERS OR
STORMS ACROSS SRN MN AS THE ATMOSPHERE BECOMES WEAKLY UNSTABLE.
THERE IS A PRONOUNCED CAP BETWEEN 600-700 MB WHICH WILL LIMIT
COVERAGE TO 20-30 PCT...AND IF CLOUD COVER IS HIGHER THAN FORECAST
THE INSTABILITY MAY NEVER EVEN MATERIALIZE.
BY FRIDAY...STRONG RIDGING WILL EMERGE OVER THE WESTERN HIGH
PLAINS FROM THE ROCKIES. SOUTH/SOUTHEASTERLY FLOW AT THE SURFACE
WILL KEEP TEMPERATURES IN THE UPPER 70S/LOWER 80S LOCALLY...BUT
TEMPERATURES WILL INCH UPWARD EACH DAY AS THE RIDGE CONTINUES
BUILDING EAST. BY SATURDAY...AN IMPRESSIVE THERMAL RIDGE WILL BE
IN PLACE OVER THE WESTERN DAKOTAS. AS THE WEEKEND PROGRESSES...
AND ESPECIALLY BY EARLY NEXT WEEK...STRONGER MID AND UPPER LEVEL
FLOW WILL BECOME ESTABLISHED OVER SOUTHERN CANADA. THIS WILL BRING
THE RIDGING FURTHER EAST INTO THE UPPER MIDWEST AND MISSISSIPPI
VALLEY. 850 MB TEMPS RISE TO AROUND 20C AND 925 MB TEMPS RISE INTO
THE MID 20S C...THUS SUMMER WILL FINALLY RETURN WITH HIGHS IN THE
MID 80S TO LOWER 90S. POPS APPEAR LOW TO NIL GIVEN THE LACK OF
FORCING. ANY CHANCES WILL BE DRIVEN ON LOCAL FEATURES TOO
DIFFICULT TO PINPOINT THIS FAR OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1048 PM CDT TUE AUG 13 2013
HIGH PRESSURE WILL DOMINATE ACROSS THE TAF SITES OVERNIGHT. STRONG
COOLING WILL LEAD TO THE CROSSOVER TEMPERATURE BEING EXCEEDED FOR
FOG PURPOSES AT KSTC...KRNH AND KEAU. HAVE HIT THE FOG HARDER AT
THESE THREE SITES WITH PREDOMINATE 1 1/2SM TEMPO 1/4SM. TIMING
REMAINS AN ISSUE WITH 08Z-12Z BEING SIMILAR TIMING TO LAST NIGHT.
HOWEVER...SOME FOG IS POSSIBLE BETWEEN 06Z-08Z. WINDS WILL
INCREASE TO 6-9 KNOTS FROM THE WSW AFTER 15Z ON WEDNESDAY ALONG
WITH SCT-BKN060 DEVELOPING.
KMSP...VFR THROUGH THE PERIOD. LIGHT WINDS OVERNIGHT BECOMING WSW
7-9 KNOTS BY LATE WEDNESDAY MORNING.
/OUTLOOK FOR KMSP/
THU...VFR. WINDS SW 5 KTS.
FRI...VFR. SLIGHT CHANCE ISOLD SHRA/TS. WINDS S 8 KTS.
SAT...VFR. WINDS SSW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
348 AM CDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT WED AUG 14 2013
IN THE VERY NEAR TERM MESOSCALE CONVECTIVE VORTICITY (MCV) MOVING
ACROSS NORTHERN NEBRASKA. HRRR MODEL WANTS TO DEVELOP MORE
CONVECTION INTO SOUTHWEST NEBRASKA THROUGH THE EARLY MORNING BUT
RADAR TRENDS SHOWING THAT FORCING DIMINISHING OVER SOUTHWEST
NEBRASKA. HAVE CONTINUED LIKELY POPS OVER NORTH CENTRAL NEBRASKA
WITH CHANCES SLOWLY TAPERING DOWN TO SLIGHT CHANCE AS THE SYSTEM
MOVES EAST. CHANCE POPS BROUGHT BACK INTO ENTIRE FORECAST AREA
THIS AFTERNOON AS A WAVE MOVES SOUTHEAST ACROSS FORECAST AREA FROM
SOUTH DAKOTA. TEMPERATURES TODAY WILL BE SKEWED BY MCV AND CLOUD
SHIELD OVER NORTH CENTRAL NEBRASKA WITH HIGH AT ONEILL 74 DEGREES.
80S TO THE WEST AND SOUTHWEST WHERE PARTLY TO MOSTLY CLOUDY SKIES
SEEN. FAIRLY ROBUST SOUTHERLY FLOW THIS AFTERNOON WITH DEW POINTS
AROUND 60. TIMING OF WAVES WILL BE KEY TO PRECIPITATION CHANCES.
LOW LEVEL JET TONIGHT WILL HELP TO SUSTAIN CONVECTION FROM THE
AFTERNOON AND HELP TO CARRY IT ACROSS THE FORECAST AREA. COOLER
TEMPERATURES AGAIN WITH LOWS BY SUNRISE IN THE MID TO UPPER 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CDT WED AUG 14 2013
A SHORTWAVE TROUGH WILL ROTATE SOUTHEAST ACROSS THE AREA THURSDAY
ON THE EASTERN PERIPHERY OF THE ROCKIES UPPER LEVEL RIDGE.
SCATTERED AFTERNOON THUNDERSTORMS ARE POSSIBLE AS THIS FEATURE
ROTATES SOUTHEAST ACROSS THE AREA. STEEP LOW AND MID LEVEL LAPSE
RATES COMBINED WITH AMPLE MOISTURE...SHOULD YIELD MODERATE TO
LOCALLY STRONG INSTABILITY BY AFTERNOON. NORTHWEST FLOW ALOFT WILL
INCREASE...AND WHEN COMBINED WITH WEAK EAST TO SOUTHEAST FLOW AT
THE SURFACE...DECENT BULK SHEAR OF 35 TO 45 KTS WILL LIKELY
SUPPORT A FEW SOUTHEAST MOVING SUPERCELLS WITH THE POTENTIAL FOR
LARGE HAIL.
AFTER THURSDAY...THE UPPER LEVEL RIDGE WILL AMPLIFY AND BUILD
NORTHEAST OVER THE AREA...BRINGING A SPELL OF DRY WEATHER FRIDAY
THROUGH SUNDAY. TEMPERATURES WILL SLOWLY WARM DURING THIS
PERIOD...WITH HIGHS RANGING FROM THE LOWER TO MID 80S FRIDAY...TO
THE MID AND UPPER 80S SUNDAY.
EARLY NEXT WEEK THE UPPER LEVEL RIDGE REMAINS ANCHORED OVER THE
AREA. MODELS ARE TRYING TO BRING A DISTURBANCE THROUGH THE REGION
ON THE SOUTHERN FRINGES OF THE NORTHERN STREAM. CONFIDENCE IS LOW
AT THIS POINT REGARDING THE TIMING AND STRENGTH OF THIS
DISTURBANCE. HAVE KEPT ANY CHANCES FOR PRECIPITATION LOW...AND
HAVE KEPT TEMPERATURES WARM WITH THE UPPER LEVEL RIDGE IN CONTROL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 120 AM CDT WED AUG 14 2013
CONVECTIVE CLUSTER AND ASSOCIATED MCV WILL MOVE ACROSS SOUTHERN SD
AND NORTHERN NE...AND POSSIBLY INTO THE SANDHILLS THROUGH THE NIGHT.
SCT TSRA HAS BEEN INCLUDED IN THE KVTN TAF THROUGH 08Z. AFTER THE
COMPLEX MOVES THROUGH THERE WILL LIKELY BE SOME STRATUS TWD SUNRISE
AS SUGGESTED BY BUFR SOUNDINGS. EARLIER GUIDANCE ALSO SUGGESTED SOME
POSSIBILITY OF BR FOR KVTN BUT LATEST GUIDANCE DOES NOT. CONFIDENCE
NOT HIGH EITHER WAY SO SINCE IT WAS INCLUDED IN EARLIER KVTN TAFS
HAS OPTED TO KEEP IT IN. FURTHER SOUTH...LATEST HRRR SUGGESTS
CONVECTIVE CLUSTER WILL EVENTUALLY PROPAGATE SOUTH AS LOW LEVEL JET
DEVELOPS. HOWEVER...AREA VWP NOT SHOWING THE DEGREE OF LLJ AS
EARLIER PROGGED AND AS SUCH THERE HAS NOT BEEN AS MUCH SWD
PROGRESSION OF THE MCS YET. HOWEVER...RAP 300K MOISTURE TRANSPORT
VECTOR ARE BEGINNING TO SHOW A SLIGHT INCREASE IN THE LAST HOUR OR
SO. CONFIDENCE NOT HIGH FOR THE COMPLEX TO HOLD TOGETHER UNTIL
13-14Z TIME FRAME AS HRRR SUGGESTS FOR KLBF TAF. THEREFORE WILL HOLD
OFF ON INCLUDING IT FOR NOW. AS FOR THE STRATUS/FOG
POTENTIAL...LATEST GUIDANCE HAS GONE AWAY FROM IFR OR LOWER CIGS AND
VSBYS REMAINING ABOVE 5SM IN BR. WILL TREND THE FORECAST IN THIS
DIRECTION FOR KLBF...AND WILL HOLD CIGS IN THE MVFR CAT. VSBY ALREADY
STARTING TO GO DOWN AT KLBF BUT WILL ALSO HAVE TO SEE WHAT EFFECT
OUTFLOW BOUNDARY HAS ON LOCAL VSBY.
NEXT FCST PROBLEM CONCERNS CONVECTIVE REDEVELOPMENT PRIOR TO 14.21Z.
BELIEVE THE SHORT RANGE MODELS ARE HAVING A TOUGH TIME
DIFFERENTIATING BETWEEN SIGNIFICANT UPPER PV ANOMALIES TO BE ABLE TO
RESOLVE THE DEGREE OF LOW LEVEL CONVERGENCE TO SUPPORT DEEP MOIST
CONVECTION. LAST FEW DAYS HAS SHOWN CONVECTION ALLOWING MODELS TO
PERFORM BETTER WITH THE IDEA OF DEVELOPMENT...WHICH MEANS CONFIDENCE
IN TSRA DEVELOPMENT BEYOND 6 HRS IS LOW. WILL SIDE WITH AN AFTERNOON
REDEVELOPMENT...WHICH WOULD BE MORE CLIMATOLOGICAL LY VIABLE...VIA A
PROB30 GROUP.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...POWER
LONG TERM...TAYLOR
AVIATION...JWS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
119 AM CDT WED AUG 14 2013
.SYNOPSIS...
ISSUED AT 242 PM CDT TUE AUG 13 2013
A THUNDERSTORM COMPLEX FROM THIS MORNING LEFT A WEAK OUTFLOW
BOUNDARY ACROSS WEST-CENTRAL NEBRASKA...WHERE A FEW THUNDERSTORMS
HAVE INITIATED OVER THE PAST HOUR. A WEAK UPPER LEVEL DISTURBANCE
EXISTS ACROSS THE DAKOTAS IN NORTHWEST FLOW ALOFT...WITH UPPER
RIDGING OVER THE INTERMOUNTAIN WEST AND AN UPPER TROUGH OVER THE
GREAT LAKES REGION.
&&
.UPDATE...
ISSUED AT 120 AM CDT WED AUG 14 2013
UPDATED FORECAST TO ACCOUNT FOR MCV MOVING ACROSS NORTHERN
NEBRASKA. UPDATED POPS AND QPF TO ACCOUNT FOR HEAVY PRECIPITATION
WITH COMPLEX...RADAR ESTIMATED.
UPDATE ISSUED AT 856 PM CDT TUE AUG 13 2013
QUICK UPDATE TO FINE TUNE PRECIPITATION CHANCES ACROSS THE AREA.
THUNDERSTORMS OVER THE SOUTHWEST HAVE DECREASED...BUT THE MCS
MOVING INTO NEBRASKA FROM SOUTH DAKOTA IS HOLDING TOGETHER WELL.
SHORT RANGE MODELS SUGGEST SOME POTENTIAL FOR MCS MAINTENANCE
THROUGH THE NEXT FEW HOURS...THOUGH MID LEVEL LAPSE RATES ARE NOT
STELLAR. GOOD POTENTIAL FOR THE NORTHERN MOST COUNTIES THOUGH FOR
THE NEXT FEW HOURS. OTHERWISE REST OF FORECAST LOOKS GOOD.
UPDATE ISSUED AT 643 PM CDT TUE AUG 13 2013
ADJUSTED PRECIPITATION CHANCES ACROSS SOUTHWEST NEBRASKA...ALONG
WITH CLOUD COVER. MOVEMENT OF THE STORMS IS VERY SLOWLY SOUTHWEST
THOUGH STORM INTERACTION HAS CAUSED VARIABLE MOVEMENT OF THE
STRONGEST UPDRAFTS. OTHERWISE REST OF FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 242 PM CDT TUE AUG 13 2013
THUNDERSTORM ACTIVITY WILL INCREASE THROUGH THE LATE AFTERNOON
HOURS ACROSS THE AREA. ACTIVITY IS CURRENTLY GETTING STARTED
ACROSS THE WEST WHERE THE BOUNDARY FROM THE MORNINGS THUNDERSTORMS
EXISTS. CAPE RUNS AROUND 1500 J/KG CURRENTLY...BUT 0-6 KM SHEAR
WEAK AT UNDER 30 KTS. A FEW STRONG STORMS WILL BE POSSIBLE...BUT
EXPECT SEVERE THREAT TO BE LIMITED DUE TO LACKING SHEAR. STEERING
WINDS WILL BE RATHER WEAK...RAISING THE RISK FOR LOCALIZED
FLOODING FROM THUNDERSTORMS TODAY. A LOW LEVEL JET WILL FAVOR
THUNDERSTORM ACTIVITY AFTER MIDNIGHT ACROSS THE NORTH AND
NORTHEAST. ALSO...LOW STRATUS AND FOG WILL BE POSSIBLE TONIGHT
BASED ON BUFR SOUNDINGS AND MOS GUIDANCE. THE MODIFIED RICHARDSON
NUMBER LOOKS TO FAVOR STRATUS MORE THAN FOG... DUE TO THE MIXING
IN THE LOWEST 100 MB. HAVE INCLUDED ONLY PATCHY FOG IN THE SOUTH
FOR LATE TONIGHT/EARLY TOMORROW MORNING. TOMORROW...AN UPPER LEVEL
WAVE MOVES THROUGH THE AREA WITH FAVORABLE INSTABILITY...BUT WEAK
SHEAR ONCE AGAIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 242 PM CDT TUE AUG 13 2013
MID TERM...WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...THUNDERSTORM
CHANCES ARE THE MAIN FORECASTING CHALLENGE AS WE APPROACH THURSDAY
AND THURSDAY NIGHT. FOR WEDNESDAY NIGHT...WITH A WEAK CAP IN
PLACE...CONVECTION IS EXPECTED TO BE ONGOING AT THE BEGINNING OF
THE PERIOD. SCATTERED SHOWERS AND THUNDERSTORMS WILL RIDE
SOUTHEAST OVERNIGHT AS NORTHWESTERLY FLOW IN THE MID LEVELS
CONTINUES. A NICE LOW LEVEL JET WILL DEVELOP ACROSS WESTERN KS
INTO CENTRAL NEBR WEDS NIGHT...WHICH WILL HELP TO SUSTAIN SHOWERS
AND THUNDERSTORMS INTO THE OVERNIGHT HOURS. DECIDED TO CONTINUE
SCATTERED COVERAGE OF PCPN...AS UPPER LEVEL FORCING AND DEEP LAYER
SHEAR REMAINS WEAK OVERNIGHT. FOR THURSDAY...RIDGING ALOFT WILL
BEGIN TO BUILD INTO THE ROCKIES WITH INCREASED MID LEVEL WAA
PUSHING INTO THE CENTRAL PLAINS LATE THURSDAY AND THURSDAY NIGHT.
CAPPING WILL BE WEAK ONCE AGAIN WHICH WILL FACILITATE EARLY
INITIATION THURSDAY AFTERNOON. UNLIKE WEDNESDAY...DEEP LAYER
SHEAR...WILL BE STRONGER...ESPECIALLY OVER CENTRAL AND SOUTHERN
NEBRASKA...WHICH MAY FACILITATE STRONG TO SEVERE THUNDERSTORMS
THURSDAY AFTERNOON/THURSDAY NIGHT. ON FRIDAY...RIDGING WILL BUILD
INTO THE NORTHERN ROCKIES AND HIGH PLAINS SHIFTING THE MID LEVEL
FLOW FROM NORTHWEST TO NORTH...EFFECTIVELY CUTTING OFF ANY MID
LEVEL SUPPORT FOR THUNDERSTORMS FRIDAY AFTERNOON AND FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH TUESDAY...DRY CONDITIONS WILL CONTINUE
INTO SATURDAY...AS WELL AS MOST OF SUNDAY AS RIDGING BUILDS EAST OF
THE ROCKIES. THE LATEST MEX GUIDANCE INCREASES MAX TEMPS INTO THE
LOWER TO MID 90S FOR SATURDAY AND SUNDAY. TRENDED TEMPS UP FOR BOTH
SATURDAY AND SUNDAY INTO THE UPPER 80S TO NEAR 90. NOT CONVINCED WE
WILL HIT THE LOWER TO MIDDLE 90S GIVEN THE FCST H85 TEMPS AND THE
FACT WE HAVE BEEN WET ACROSS THE FCST AREA OVER THE PAST COUPLE OF
WEEKS. RIDGING WILL BEGIN TO BREAK DOWN LATE SUNDAY AS A TROUGH OF
LOW PRESSURE PUSHES INTO THE WESTERN ROCKIES. AS THIS FEATURE
APPROACHES THE CENTRAL PLAINS SUNDAY NIGHT INTO
MONDAY...THUNDERSTORM CHANCES WILL INCREASE FOR MONDAY INTO TUESDAY.
HIGHS ON MONDAY AND TUESDAY WILL BE IN THE LOWER TO MID 80S THANKS
TO INCREASED MOISTURE AND CLOUD
COVER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 120 AM CDT WED AUG 14 2013
CONVECTIVE CLUSTER AND ASSOCIATED MCV WILL MOVE ACROSS SOUTHERN SD
AND NORTHERN NE...AND POSSIBLY INTO THE SANDHILLS THROUGH THE NIGHT.
SCT TSRA HAS BEEN INCLUDED IN THE KVTN TAF THROUGH 08Z. AFTER THE
COMPLEX MOVES THROUGH THERE WILL LIKELY BE SOME STRATUS TWD SUNRISE
AS SUGGESTED BY BUFR SOUNDINGS. EARLIER GUIDANCE ALSO SUGGESTED SOME
POSSIBILITY OF BR FOR KVTN BUT LATEST GUIDANCE DOES NOT. CONFIDENCE
NOT HIGH EITHER WAY SO SINCE IT WAS INCLUDED IN EARLIER KVTN TAFS
HAS OPTED TO KEEP IT IN. FURTHER SOUTH...LATEST HRRR SUGGESTS
CONVECTIVE CLUSTER WILL EVENTUALLY PROPAGATE SOUTH AS LOW LEVEL JET
DEVELOPS. HOWEVER...AREA VWP NOT SHOWING THE DEGREE OF LLJ AS
EARLIER PROGGED AND AS SUCH THERE HAS NOT BEEN AS MUCH SWD
PROGRESSION OF THE MCS YET. HOWEVER...RAP 300K MOISTURE TRANSPORT
VECTOR ARE BEGINNING TO SHOW A SLIGHT INCREASE IN THE LAST HOUR OR
SO. CONFIDENCE NOT HIGH FOR THE COMPLEX TO HOLD TOGETHER UNTIL
13-14Z TIME FRAME AS HRRR SUGGESTS FOR KLBF TAF. THEREFORE WILL HOLD
OFF ON INCLUDING IT FOR NOW. AS FOR THE STRATUS/FOG
POTENTIAL...LATEST GUIDANCE HAS GONE AWAY FROM IFR OR LOWER CIGS AND
VSBYS REMAINING ABOVE 5SM IN BR. WILL TREND THE FORECAST IN THIS
DIRECTION FOR KLBF...AND WILL HOLD CIGS IN THE MVFR CAT. VSBY ALREADY
STARTING TO GO DOWN AT KLBF BUT WILL ALSO HAVE TO SEE WHAT EFFECT
OUTFLOW BOUNDARY HAS ON LOCAL VSBY.
NEXT FCST PROBLEM CONCERNS CONVECTIVE REDEVELOPMENT PRIOR TO 14.21Z.
BELIEVE THE SHORT RANGE MODELS ARE HAVING A TOUGH TIME
DIFFERENTIATING BETWEEN SIGNIFICANT UPPER PV ANOMALIES TO BE ABLE TO
RESOLVE THE DEGREE OF LOW LEVEL CONVERGENCE TO SUPPORT DEEP MOIST
CONVECTION. LAST FEW DAYS HAS SHOWN CONVECTION ALLOWING MODELS TO
PERFORM BETTER WITH THE IDEA OF DEVELOPMENT...WHICH MEANS CONFIDENCE
IN TSRA DEVELOPMENT BEYOND 6 HRS IS LOW. WILL SIDE WITH AN AFTERNOON
REDEVELOPMENT...WHICH WOULD BE MORE CLIMATOLOGICAL LY VIABLE...VIA A
PROB30 GROUP.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...POWER
SYNOPSIS...KNUTSVIG
SHORT TERM...KNUTSVIG
LONG TERM...CLB
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1235 AM CDT WED AUG 14 2013
.UPDATE...
ISSUED AT 1235 AM CDT WED AUG 14 2013
ESSENTIALLY NO CHANGES MADE FOR THIS ESTF UPDATE. HOWEVER...WE ARE
MONITORING THE MCS OVER THE SANDHILLS...BTWN VTN AND AIA. WE MAY
BE MAKING SUBSTANTIAL CHANGES LATER THIS MRNG BASED ON RADAR TRENDS.
UPDATE ISSUED AT 934 PM CDT TUE AUG 13 2013
ONGOING CONVECTION CURRENTLY IN SW SOUTH DAKOTA/NW NEB IS PROGGED
TO REACH OUR NORTHERN CWA LATE TONIGHT/TOWARD WEDNESDAY MORNING
AND REORIENTED AND INCREASED POPS FOR WED TO ACCOUNT FOR THIS.
ALSO TONIGHT...INCLUDED PATCHY FOG FOR ALL AREAS WITH LIGHT
EASTERLY LLVL FLOW AND RECENT RAINFALL/MOISTURE. STILL SOME
UNCERTAINTY ON HOW LOW VSBYS WILL DROP AND WILL NEED TO MONITOR
TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
WE HAD A MESOSCALE CONVECTIVE VORTEX (MCV) TRACK ACROSS OUR FORECAST
AREA THIS MORNING INTO THE EARLY AFTERNOON HOURS. THIS BROUGHT
WIDESPREAD RAINFALL TO OUR FORECAST AREA AND HAS WORKED OVER THE
ATMOSPHERE ENOUGH THAT ADDITIONAL PRECIPITATION THIS EVENING INTO
TONIGHT IS UNLIKELY. THE CONVECTION THAT TRACKED THROUGH OUR AREA
HAS NOW PASSED SOUTH INTO CENTRAL KANSAS AND NEW STORMS HAVE ALSO
FORMED TO OUR WEST OVER THE HIGH PLAINS OF WESTERN NEBRASKA.
THE WESTERN NEBRASKA THUNDERSTORMS HAVE FORMED ALONG THE LEADING
EDGE OF THE NEXT SHORTWAVE THAT IS TRACKING SOUTHEAST FROM EASTERN
WYOMING/SOUTHWEST SOUTH DAKOTA INTO WESTERN NEBRASKA. DEEP MOISTURE
CONVERGENCE AND AFTERNOON DESTABILIZATION IS ALSO MAXIMIZED ACROSS
WESTERN NEBRASKA INTO THE BLACK HILLS AND THIS IS WHERE ADDITIONAL
THUNDERSTORMS ARE EXPECTED TO FORM THIS EVENING. THIS IS A WEAKLY
SHEARED ENVIRONMENT AND STORM PROPAGATION WILL GENERALLY BE A SLOW
DRIFT TO THE SOUTH...WHICH SHOULD KEEP THE WESTERN STORMS JUST TO
THE WEST OF OUR FORECAST AREA TONIGHT. THERE IS AN OUTSIDE CHANCE OF
OUR WESTERN ZONES SEEING A PREDAWN SHOWER/THUNDERSTORM SHOULD THE
BLACK HILLS CONVECTION MAKE IT THIS FAR SOUTHEAST. HOWEVER...MOST
FORECAST MODEL DATA KEEPS ALL CONVECTION WEST OF OUR FORECAST AREA
TONIGHT AND THUS WE WILL KEEP ALL ZONES DRY TONIGHT...WHILE KEEPING
AN EYE ON THE WEST FOR THE POSSIBILITY OF NEEDING TO THROW SOME POPS
IN THE FORECAST DEPENDING ON FUTURE RADAR TRENDS.
THERE IS SOME POTENTIAL OF FOG TONIGHT GIVEN THE RECENT WIDESPREAD
RAINFALL. HOWEVER...FORECAST MODELS ARE MIXED ON FOG POTENTIAL WITH
THE HRRR MORE FAVORABLE FOR FOG WHILE THE SREF WOULD NOT GIVE US ANY
FOG. ULTIMATELY FOG WILL LARGELY HINGE ON CLOUD COVER AND SUBSEQUENT
COOLING. HAVE LEFT FOG OUT OF THE FORECAST FOR NOW...BUT SHOULD WE
CLEAR OUT AND REMAIN CLEAR THROUGH MOST OF THE NIGHT...THEN COOLING
MIGHT BE ADEQUATE FOR SOME AREAS OF FOG EARLY WEDNESDAY MORNING.
WEDNESDAY...A SHORT WAVE TROUGH WILL TRACK SOUTHEAST ACROSS WESTERN
NEBRASKA. INSTABILITY AND DEEP LAYER SHEAR WILL BE FAIRLY WEAK TO
MODEST AT BEST AND THUS AM NOT EXPECTING SEVERE WEATHER...BUT CAN
NOT RULE OUT A COUPLE OF STRONG THUNDERSTORMS IN ASSOCIATION WITH
PEAK AFTERNOON HEATING. THE BEST CHANCE OF THUNDERSTORMS WILL BE
ACROSS OUR WESTERN ZONES AND TO THE WEST OF OUR FORECAST AREA IN
ASSOCIATION WITH THE APPROACHING SHORTWAVE. TEMPERATURES WILL REMAIN
COOL FOR AUGUST DUE TO A CONTINUATION OF THE COOL AIRMASS
OVERHEAD...CLOUDS...AND POSSIBLE PRECIPITATION. HIGHS WILL GENERALLY
BE IN THE UPPER 70S TO LOWER 80S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
THE MAIN HIGHLIGHTS OF THIS 6-DAY PERIOD ARE A CONTINUATION OF
CHALLENGING SHOWER/THUNDERSTORM CHANCES IN THE WED NIGHT THROUGH
FRIDAY TIME FRAME WHICH MIGHT EVEN FEATURE A STRONG-SEVERE STORM
THREAT CENTERED ON THURSDAY...FOLLOWED BY WHAT APPEARS TO BE A
PREDOMINANTLY DRY WEEKEND...AND THEN A RETURN TO VERY UNCERTAIN
RAIN CHANCES IN THE SUNDAY NIGHT-TUESDAY TIME FRAME AS THE PATTERN
CHANGES A BIT. ITS BEEN A TOUGH GO OF IT LATELY TRYING TO
DETERMINE HOW HARD TO HIT...OR BACK OFF...POPS EVEN IN THE FIRST
24 HOURS...SO THESE UNCERTAINTIES CONTINUE TO BE MAGNIFIED EVEN IN
THE DAY 2-3 TIME FRAME. OF HIGHER CONFIDENCE IS THAT A FAIRLY
REMARKABLE RUN OF SUB-90 DEGREE TEMPS WILL CONTINUE...WITH THE
MAJORITY OF THE CWA FORECAST TO TOP OUT IN THE LOW-MID 80S DURING
THIS TIME FRAME...WITH KS ZONES AS USUAL MOST FAVORED TO REACH
UPPER 80S ON A FEW DAYS. AS FOR LOW TEMPS...EVERY NIGHT IS
EXPECTED TO BE FAIRLY SIMILAR AND RATHER UNIFORM ACROSS THE
CWA...EITHER IN THE LOW OR MID 60S.
STARTING OFF WEDNESDAY EVENING/NIGHT...GAVE A BEST-STAB AT TWO
6-HOUR POP BLOCKS HEAVILY BASED ON MET/MAV GUIDANCE BLEND...WITH
THE EVENING PERIOD FEATURING 20S-40S...AND THE LATE NIGHT PERIOD
RANGING FROM ONLY 20S FAR WEST TO 50S IN EASTERN-MOST NEB ZONES.
IN OTHER WORDS...THERE IS A DECENT CHANCE THAT PARTS OF THE CWA
WILL SEE RAIN...BUT CONFIDENCE IN TIMING/PLACEMENT PRECLUDES
LIKELY POPS ANYWHERE YET. ON THE LARGE-SCALE ALOFT...LEGITIMATE
NORTHWEST-FLOW IS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN A
RIDGE AXIS EXTENDING NORTHWARD ACROSS THE ROCKIES FROM NORTHERN
MEXICO INTO SOUTHWEST CANADA...AND A BROAD TROUGH ANCHORED OVER
SOUTHEAST CANADA/THE NORTHEAST CONUS. ON A MORE LOCAL/REGIONAL
LEVEL...THE CWA IS PROGGED TO REMAIN UNDER/NEAR THE MAIN TRACK OF
LOW-AMPLITUDE SHORTWAVE TROUGHS RIPPLING THROUGH THE NORTHWEST
FLOW. STARTING OFF RIGHT AWAY WED EVENING AT 00Z/7PM...ITS
EXPECTED THAT AT LEAST A SMALL PART OF THE CWA SHOULD BE SEEING
ACTIVITY PERSISTING FROM THE LATE AFTERNOON HOURS...ALTHOUGH MODEL
QPF/REFLECTIVITY FIELDS VARY CONSIDERABLY ON THE MOST FAVORED
AREA. AS THE NIGHT WEARS ON...THERE IS A DECENT SIGNAL FOR WARM
AIR ADVECTION/MOISTURE TRANSPORT IN THE 850-700 MILLIBAR
LAYER...WITHIN THE AXIS OF A MODEST 20+KT SOUTHWESTERLY LOW LEVEL
JET. PER THE 12Z/18Z NAM AND LAST FEW SREF RUNS...THIS WOULD FAVOR
EASTERN ZONES FOR THE HIGHEST LATE NIGHT POPS...WHILE THE
ECWMF/GFS WOULD MORE-SO FAVOR CENTRAL/SOUTHWEST ZONES. AS FOR
THUNDERSTORM INTENSITY...ALTHOUGH NOT EXPECTING A WIDESPREAD
NOCTURNAL SEVERE THREAT...CERTAINLY A FEW STRONG TO MARGINALLY
SEVERE STORMS WITH MAINLY A HAIL/LOCALLY HEAVY RAIN THREAT CANNOT
BE RULED OUT GIVEN MUCAPE INCREASING TO AT LEAST 500-1000 J/KG IN
THE PRESENCE OF AROUND 25KT OF DEEP LAYER SHEAR.
THURSDAY/THURSDAY NIGHT...THIS 24 HOURS WOULD APPEAR TO CONTAIN
THE OVERALL-HIGHEST THREAT OF SEVERE STORMS DURING THE NEXT
SEVERAL DAYS...ALTHOUGH THE JURY IS STILL OUT ON WHETHER IT WOULD
BE MORE LOCALIZED OR MORE WIDESPREAD. CERTAINLY WOULD NOT BE
SURPRISED TO SEE THE UPCOMING SPC DAY 2 OUTLOOK INTRODUCE A SLIGHT
RISK FOR ALL/PART OF THE CWA...MAINLY FOR THE AFTERNOON/EVENING
HOURS. IN THE BIG PICTURE...SEASONABLY STRONG/SHARP NORTHWEST FLOW
STRENGTHENS AB IT...AS MODELS ARE IN DECENT AGREEMENT IN DRIVING A
BIT STRONGER/ORGANIZED SHORTWAVE TROUGH SOUTHWARD OUT OF WESTERN
SD ACROSS THE HEART OF CENTRAL NEB/KS. FOR THE MORNING
HOURS...KEPT POPS AT SLIGHT 20S EXCEPT 30S IN THE EAST WHERE
SEEMINGLY THE BEST CHANCE OF LINGERING OVERNIGHT CONVECTION WOULD
BE. THEN HAVE 30 POPS NEARLY ALL AREAS DURING THE AFTERNOON TO
ACCOUNT FOR THUNDERSTORM REDEVELOPMENT AND/OR
RE-INTENSIFICATION...ASSUMING OF COURSE THAT SUFFICIENT HEATING
CAN TAKE PLACE. ITS STILL TOO SOON TO TELL THOUGH WHETHER
POTENTIALLY VIGOROUS AFTERNOON ACTIVITY MAINLY DEVELOPS LOCALLY OR
MOVES IN FROM THE NORTHWEST. AT ANY RATE...THE 18Z NAM DEPICTS A
FAIRLY POTENT NORTHWEST FLOW SEVERE ENVIRONMENT WITH MIXED LAYER
CAPE 2000+ J/KG IN THE PRESENCE OF DECENT 30-40 KNOT DEEP LAYER
SHEAR...MAKING A FEW SUPERCELLS A POSSIBILITY IF THE MESOSCALE
FEATURES COME TOGETHER. FOR THURSDAY EVENING/NIGHT...KEPT 30-50
POPS GOING AREA-WIDE...HIGHEST IN THE FAR SOUTH. NOT ACCOUNTING
FOR POSSIBLE CONVECTIVE EFFECTS...BREEZES DURING THE DAY THURSDAY
ARE EXPECTED TO AVERAGE AROUND 10 MPH FROM THE SOUTH.
FRIDAY/FRIDAY NIGHT...THE LATEST NAM/GFS ARE IN GOOD AGREEMENT
AMPLIFYING THE WESTERN CONUS RIDGE EASTWARD OVER THE CENTRAL
PLAINS...RESULTING IN MODEST HEIGHT RISES AND NEARLY DUE-NORTHERLY
FLOW ALOFT. THIS SHOULD RESULT IN A LESS-FAVORABLE ENVIRONMENT FOR
THUNDERSTORM DEVELOPMENT. HOWEVER...KEPT THE MAJORITY OF THE CWA
WITH SLIGHT POPS DURING THE DAYTIME HOURS MAINLY TO ACCOUNT FOR
POSSIBLE DIURNAL-HEATING INDUCED CONVECTION...BUT LEFT FRIDAY
NIGHT DRY PER PREVIOUS FORECAST.
SATURDAY THROUGH SUNDAY...KEPT THE DRY FORECAST GOING CWA-
WIDE...AS SEEMINGLY-BENIGN NORTHERLY FLOW REMAINS IN PLACE ALOFT
TO THE EAST OF THE ROCKIES-CENTERED RIDGE AXIS. BOTH THE ECWMF/GFS
KEEP THE MAIN BRANCHES OF STRONGER FLOW ALOFT WELL NORTH NEAR THE
CANADIAN BORDER...AND ALSO IN THE SOUTHEAST STATES...WITH THE CWA
ALSO STAYING SAFELY NORTHWEST OF A STALLED...POSSIBLY RETROGRADING
CLOSED MID LEVEL LOW OVER THE SOUTHERN MO/AR AREA ADVERTISED MORE
SO BY THE ECMWF THAN THE GFS. NOT READY TO GUARANTEE A DRY WEEKEND
YET...BUT AT LEAST FOR NOW POPS HAVE BEEN KEPT IN THE SILENT 5-10
RANGE. GIVEN THAT THE AREA HAS SEEN VERY LITTLE IN THE WAY OF NON-
CONVECTIVE BREEZE LATELY...ITS WORTH NOTING THAT THE CURRENT
SUNDAY FORECAST ACTUALLY HAS SUSTAINED SOUTHERLY SPEEDS UP AROUND
15 MPH/GUSTS AROUND 20 MPH.
SUNDAY NIGHT THROUGH TUESDAY MARKS THE RETURN OF VARIOUS...LOW-
CONFIDENCE THUNDERSTORM CHANCES OF THE 20-30 PERCENT
VARIETY...THAT WILL UNDOUBTEDLY BE REFINED SEVERAL TIMES DURING
THE NEXT SEVERAL DAYS. FROM A GENERAL...SYNOPTIC SCALE
STANDPOINT...BOTH THE ECWMF/GFS BREAK DOWN THE RIDGE-DOMINATED
PATTERN FROM THE WEEKEND AND GRADUALLY BRINGS A QUASI-ZONAL
PATTERN AS ONE OR TWO FAIRLY LOW-AMPLITUDE SHORTWAVE TROUGHS OF
NOTE WORK INTO THE CENTRAL PLAINS FROM THE WEST. THIS SHOULD
SUPPORT A CONTINUED SURFACE PATTERN OF LIGHT BUT NOTICEABLY
SOUTHERLY BREEZES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1235 AM CDT WED AUG 14 2013
REST OF TNGT: VFR MAY EVENTUALLY DECAY TO MVFR VSBYS IN LGT FOG.
DWPT DEPRESSIONS ARE SMALL AND VSBYS TO THE E ARE NOW 7-9SM. THERE
DOES NOT APPEAR TO BE MUCH MSTR ALOFT...SO DO NOT EXPECT IFR FOG
ATTM. WINDS WILL BE LGT FROM THE E.
WED: WE ARE MONITORING THE MCS OVER THE SANDHILLS N OF LBF. IF
THIS CLUSTER OF TSTMS HOLDS TOGETHER...CURRENT TIMING WOULD BRING
IT INTO GRI 12-13Z. CIG/VSBYS WILL DECAY IN +TSRA WITH LLWS AND
VARIABLE/GUSTY WINDS. THEN VFR THEREAFTER. SCT TSTMS SHOULD
REDEVELOP LATE THIS AFTN OR THIS EVNG. WINDS WILL BECOME SE BUT
REMAIN BELOW 10 KTS.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: LOW
WIND CONFIDENCE: HIGH EXCEPT NEAR ANY TSTMS
WX CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS NORMAN OK
1116 PM CDT TUE AUG 13 2013
.AVIATION...
06Z TAFS... MVFR/VFR CEILINGS EXPECTED THROUGH THE PERIOD.
HOWEVER... IFR CEILINGS ALONG WITH PATCHY FOG COULD BE POSSIBLE
AT A FEW SITES NORTHERN/WESTERN OK. SCATTERED SHOWERS/STORMS WILL
BE POSSIBLE ACROSS PARTS OF WESTERN/SOUTHERN OK AND NORTH TEXAS
WED AFTN. STRONG VARIABLE WINDS WILL BE POSSIBLE NEAR ANY STORMS.
&&
.PREV DISCUSSION... /ISSUED 946 PM CDT TUE AUG 13 2013/
UPDATE...
REDUCED RAIN CHANCES ACROSS MUCH OF THE AREA FOR THE REST OF
TONIGHT. ADDED PATCHY FOG MENTION ACROSS THE NORTHWEST HALF OF
OKLAHOMA LATER TONIGHT INTO WEDNESDAY MORNING.
DISCUSSION...
RAIN CHANCES HAVE DIMINISHED FOR NOW. THEY MAY INCREASE AFTER 3
AM NEAR AND SOUTH OF THE RED RIVER.
BAND OF SHOWERS FROM WEATHERFORD TO STILLWATER CONTINUES TO
DIMINISH. GENERALLY...EXPECT THIS TREND TO CONTINUE. KEPT 20
TO 40 PERCENT RAIN CHANCES IN THESE AREAS.
LATEST HRRR/RAP13 SUGGESTS THAT A FEW MORE SHOWERS AND STORMS MAY
DEVELOP NEAR AND SOUTH OF THE RED RIVER AFTER 3 PM TONIGHT WHERE
DEEPER MOISTURE AND INSTABILITY EXIST. KEPT 20 TO 30 PERCENT
CHANCES IN THESE AREAS. NO SEVERE STORMS ARE EXPECTED...THOUGH
LOCALLY HEAVY DOWNPOURS MAY BE POSSIBLE.
FOG MAY BE A CONCERN LATE TONIGHT INTO WEDNESDAY MORNING WITH
MOIST UPSLOPE FLOW PARTICULARLY OVER NORTHWEST OKLAHOMA. ADDED
PATCHY FOG MENTION DUE TO MODERATE CONFIDENCE OF OCCURRENCE.
WIDESPREAD DENSE FOG REMAINS UNLIKELY.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 629 PM CDT TUE AUG 13 2013/
AVIATION...
0Z TAFS... SHOWERS/STORMS WILL AFFECT KPNC THIS EVENING. THIS
ACTIVITY MAY MAKE IT AS FAR SOUTH AS KOKC/KOUN BUT CHANCES TOO LOW
FOR MENTION ATTM. SHOWERS/STORMS WILL BE POSSIBLE AGAIN WED AFTN
ACROSS PARTS OF SOUTHERN/WESTERN OK AND NORTH TEXAS BUT CHANCES
ALSO TOO LOW AT SOME SITES FOR MENTION IN TAF. SOME IFR CEILINGS
COULD DEVELOP OVERNIGHT IN SOME LOCATIONS, OTHERWISE VFR/MVFR
CONDITIONS EXPECTED.
PREV DISCUSSION... /ISSUED 603 PM CDT TUE AUG 13 2013/
UPDATE...
INCREASED RAIN CHANCES THROUGH 10 PM THIS EVENING ACROSS FAR
NORTHERN OKLAHOMA...AND DECREASED THEM ELSEWHERE.
DISCUSSION...
SHOWERS AND A FEW THUNDERSTORMS WITH LOCALLY HEAVY
RAINFALL OF 1 TO 2 INCHES MAY OCCUR THIS EVENING ACROSS
FAR NORTHERN OKLAHOMA...NORTH OF A FREEDOM TO FAIRVIEW TO
STILLWATER LINE. THIS COMPLEX CONTINUES TO SLOWLY DRIFT
SOUTH...BUT SHOULD WEAKEN OVER NEXT FEW HOURS DUE TO THE
LOSS OF DAYTIME HEATING. THESE STORMS SHOULD STAY BELOW
SEVERE LIMITS DUE TO WEAK INSTABILITY. LATEST MODELS HAVE BEEN
MISHANDLING THIS COMPLEX...EXCEPT FOR THE HRRR WHICH SUGGESTS
THESE STORMS WILL QUICKLY DIMINISH AROUND SUNSET.
STORMS HAVE DIMINISHED ACROSS WESTERN NORTH TEXAS. THERE IS
CHANCE THAT A FEW ADDITIONAL STORMS DEVELOP OR MOVE INTO THESE
AREAS FROM THE WEST OVER THE NEXT SEVERAL HOURS.
ACROSS THE REST OF THE AREA...KEPT A 20 PERCENT CHANCE FOR
STORMS TONIGHT. WITHOUT A STRONG FOCUS TO PROVIDE LIFT...BELIEVE
MOST PLACES WILL REMAIN DRY. MAY UPDATE LATER THIS EVENING
TO ADJUST RAIN CHANCES DOWNWARD.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 344 PM CDT TUE AUG 13 2013/
DISCUSSION...
MAIN AREA OF CONVECTION OVER CENTRAL/SOUTH CENTRAL
KANSAS WILL CONTINUE TO DRIFT SOUTH AND SOUTHEAST
THIS AFTERNOON AND EARLY EVENING. STORMS SHOULD
GRADUALLY DECREASE IN COVERAGE AND INTENSITY
BY THE EARLY EVENING.
OTHER STORMS HAVE FORMED ACROSS NORTH TEXAS AND THE SOUTHERN
TEXAS PANHANDLE WHERE TEMPERATURES HAVE WARMED INTO THE LOWER AND
MID 90S. A FEW STRONG STORMS WILL BE POSSIBLE THROUGH THE LATE
AFTERNOON/EARLY EVENING WITH STRONG WINDS AND HEAVY RAINFALL
THE MAIN HAZARDS.
THE CENTER OF HIGH PRESSURE AND DRIER AIR WILL BUILD FROM THE
NORTHERN PLAINS INTO THE UPPER MIDWEST/MID MISSISSIPPI VALLEY
TONIGHT INTO WEDNESDAY. THIS WILL FILTER DRIER AIR INTO NORTHERN
AND EASTERN PARTS OF THE FA...AND DECREASE RAIN CHANCES IN THE
SHORT TERM.
A COUPLE OF WAVES WILL MOVE THROUGH A NORTH TO NORTHWEST
FLOW THURSDAY INTO EARLY FRIDAY. THIS WILL BRING AN
INCREASE IN SHOWER AND STORM CHANCES DURING THIS
PERIOD...ESPECIALLY ACROSS THE NORTHERN HALF OF
OKLAHOMA.
MAINLY DRY CONDITIONS ARE EXPECTED OVER THE WEEKEND AS
AN UPPER RIDGE BUILDS SLOWLY EAST. BY EARLY NEXT WEEK...
THE GFS IN MORE AGGRESSIVE IN WEAKENING THE RIDGE AS
ANOTHER TROUGH MOVES ACROSS THE NORTHERN AND CENTRAL
ROCKIES. THIS WOULD PROVIDE ANOTHER OPPORTUNITY FOR
SHOWERS AND STORMS. THE EC HOLDS MORE RIDGING ALOFT
ACROSS THE SOUTHERN PLAINS. FOR NOW WILL MAINTAIN
A DRY FORECAST WITH VERY WARM/HOT TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 70 83 67 84 / 20 20 10 20
HOBART OK 69 86 69 86 / 20 30 20 20
WICHITA FALLS TX 73 89 72 89 / 20 40 20 30
GAGE OK 64 82 66 85 / 10 20 30 30
PONCA CITY OK 64 82 64 83 / 20 10 10 20
DURANT OK 72 87 67 88 / 10 40 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25/25
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1157 PM CDT TUE AUG 13 2013
.AVIATION...
SECOND WAVE OF STORMS NEARING THE DKR REGION HAVE BEGUN TO WEAKEN
QUICKLY AND ANOTHER CLUSTER DEVELOPING AGAIN TO THE NORTHWEST OF
DKR. MODEL SOUNDINGS AND ACARS SHOW THE WARM SOUNDINGS (CAPPED)
DOWN ACROSS THE AREA TERMINALS OVERNIGHT - THOUGH THIS THIRD WAVE
MAY MAKE A BIT MORE PROGRESS AND COULD BRING A WINDSHIFT TO UTS
BETWEEN 07-10Z. OTHERWISE PREVIOUS PACKAGE STILL LOOKS CLOSE BUT
TRENDING A LITTLE LATER WITH THE RAINFALL AND CONFIDENCE HAS GROWN
THAT LATE AFTERNOON AND EARLY EVENING WILL PROBABLY BE THE BEST
WINDOW FOR SHRA/TSRA AT IAH/HOU TERMINALS. WINDS SHOULD SWING TO
THE NW LATE MORNING AND EARLY AFTERNOON (OUTFLOW) THEN NORTHEAST
IN THE AFTERNOON AS BROAD DIFFUSE FRONTAL BOUNDARY SAGS SOUTH.
DECREASING COVERAGE THROUGH THE EVENING HOURS AND MAY BE JUST SHRA
AFTER 02Z/15. LINGERING LL MOISTURE WILL ALSO PROBABLY LEAD TO
SOME PATCHY MVFR CIGS AFTER 06Z/15. 45
&&
.PREV DISCUSSION... /ISSUED 941 PM CDT TUE AUG 13 2013/
UPDATE...
SEE DISCUSSION FOR EVENING UPDATE.
DISCUSSION...
SHOWERS AND THUNDERSTORMS ACROSS THE CWA BORDER HAVE HAD TROUBLE
MOVING SOUTHWARDS THIS EVENING. THIS ACTIVITY IS IN RESPONSE TO A
WEAK FRONTAL BOUNDARY THAT IS SAGGING SOUTHWARDS. RAIN LOOKS TO
START IN THE NORTHEASTERN COUNTIES EARLY THIS MORNING THEN SLOWLY
SPREAD TOWARDS THE SOUTH WITH THE BOUNDARY DURING THE DAY. THE
CHANCE OF RAIN OVERNIGHT DOES LOOK TO BE IN QUESTION AS DRY MID-
LEVEL AIR REMAINS IN PLACE (ESPECIALLY FURTHER TOWARDS THE
SOUTH). THIS CAN BE SEEN IN THE 0Z SOUNDING FROM KCRP THAT REVEALS
A PWAT OF ONLY 1.50". THE KFWD SOUNDING ON THE OTHER HAND HAS A
PWAT VALUE OF OVER 2.00". MODELS ARE FORECASTING FOR THE DRY AIR
TO BE PUSHED SOUTHWARDS TOMORROW BUT THE EXACT TIMING OF THIS WILL
BE TOUGH TO PREDICT. LIFT TOMORROW WILL COME FROM THE DIFFUSE
BOUNDARY WHICH SHOULD MAKE IT TO JUST NORTH OF INTERSTATE 10.
CONVECTIVE OUTFLOWS WILL THEN PUSH SOUTHWARDS LATER IN THE DAY
AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. THERE SHOULD BE
ENOUGH DAYTIME HEATING TO ALLOW FOR CONVECTIVE TEMPERATURES TO BE
REACHED. THE SOUTHWESTERN ZONES WILL BE THE LAST TO SEE THE RAIN
AND COVERAGE SHOULD BE LESS DUE TO THE LOWER MOISTURE AND WEAKER
LAPSE RATES. UPPER LEVEL SUPPORT ALSO APPEARS TO BE MORE OFF
TOWARDS THE EAST TOMORROW. GIVEN THESE TRENDS HAVE PULLED POPS
BACK SLIGHTLY. NEW ZONES WILL BE OUT SHORTLY. 23
PREV DISCUSSION... /ISSUED 814 PM CDT TUE AUG 13 2013/
AVIATION...
STORMS ALONG AND SOUTH OF A VERY DIFFUSE FRONTAL BOUNDARY HAVE
BEEN WANING QUICKLY. SOME HIGH CLOUDS WILL DRIFT SOUTHEAST INTO
THE AREA OVERNIGHT. VFR CONDITIONS SHOULD PREVAIL OVERNIGHT WITH
SOME SHOWERS AND POSSIBLY A THUNDERSTORM NORTHEAST OF THE UTS
TERMINAL. TOMORROW IS NOT SO STRAIGHT FORWARD...THE DIFFUSE FRONT
CONTINUES TO SAG SOUTHWARD AS UPPER LEVEL RIDGING (CAPPING) OVER
CENTRAL AND SOUTHERN TX SLIDES SLOWLY WEST AND TROUGHING DIPS
DOWN INTO LA. RICH MOISTURE AND COOLING TEMPERATURES ALOFT IN
COMBINATION WITH A LL FOCUS POINTS TOWARDS THE DEVELOPMENT OF
SHRA/TSRA BUT MODELS ARE IN DISAGREEMENT WITH RESPECT TO TIMING
AND LOCATION BETWEEN 12Z AND 03Z/14 AND IN SOME CASES WIDELY. NOT
THAT CONFIDENT CONVECTION WILL BE WIDESPREAD IN THE NORTH IN THE
MORNING BUT AS HEATING INCREASES EXPECT THAT AT LEAST SCATTERED
SHRA/TSRA SHOULD DEVELOP. EVENTUALLY OUTFLOW SPREADS SOUTH AND
SHOULD REACH THE METRO TERMINALS MID TO LATE AFTERNOON SO PEAK IN
ACTIVITY WILL PROBABLY BE IN THE AFTERNOON FOR THE HOUSTON AREA
TERMINALS. STORMS SHOULD WANE AGAIN TOMORROW EVENING ESPECIALLY IN
THE SOUTHWEST WHERE STRONGER CAP WILL STILL BE IN PLACE. 45
PREV DISCUSSION... /ISSUED 346 PM CDT TUE AUG 13 2013/
DISCUSSION...
MUCH CONVECTIVE ACTIVITY OCCURRING ALONG A NORTHERN TEXAS (QUASI)
STATIONARY BOUNDARY THAT MAY EVENTUAL IMPACT OUR NORTH(EAST)ERN
COUNTIES WITHIN THE NEXT 4 TO 6 HOURS. A VERY HEATED AND MOIST
DOWNSTREAM AIR MASS FOR THIS STATIONARY BOUNDARY...OR SUBSEQUENT
CONVECTIVE OUTFLOW...TO WORK WITH IN THE COMING 24-36 HOURS.
THERE IS STILL SUBSIDENCE TO WORK WITH AS THERE HAVE BEEN RECENT
HEIGHT RISES AND A FEW DEGREES OF WARMTH AT THE 85-7H LEVELS...BUT
THE UPPER LEVELS REMAIN FAIRLY DIFFLUENT AS EAST TEXAS FALLS
WITHIN A (RELATIVELY) MILD MID-UPPER LEVEL HEIGHT WEAKNESS BETWEEN
DESERT SOUTHWEST AND FLORIDA-CENTERED RIDGING.
ALL OF THE THERMODYNAMIC INDICES ARE THERE TO SUPPORT RETURNING
SCATTERED SHOWERS AND STORMS BEGINNING AS EARLY AS MID-WEDNESDAY
MORNING. K-INDICES AROUND 40...L.I. IN THE -5 REALM...AND ABOVE
1 K J/KG CAPES FROM THE GFS/NAM PROGS OVER THE NORTHERN CWA
INCREASE THE SHOWER/STORM PROBABILITY. YES...THERE WILL BE SOME
SUBSIDENCE TO DEAL WITH...BUT WITH A CONSISTENT RUN-TO-RUN THEME
OF INTRODUCING WEAK LOWER MS VALLEY TROUGHING (AND WITNESSING WHAT
IS ONGOING ACROSS DFW`S FA)...HAD TO BITE ON THE LIKELY SIDE OF
POPS. GREATER THAN 2 INCH PWATS WILL POOL ALONG `A` BOUNDARY...WHETHER
THAT BE MORE OF A SYNOPTIC OR A SERIES OF MESOSCALE (UPSTREAM
OUTFLOW) BOUNDARIES. OTHER THAN SUBSIDENCE AS A RAIN INHIBITER...THE
ONLY OTHER NEGATIVE TO MORE WIDESPREAD COVERAGE WOULD BE THAT THE
REGION DOES FALL INTO MORE OF A RR QUAD OF THE JET (ALTHOUGH 25-3H
FLOW REMAINS DIFFLUENT).
NEEDLESS TO SAY...BUT WHAT EVOLVES TOMORROW WILL DRIVE THURSDAY`S
FORECAST. SINCE THE FORECAST IS MORE WET TOMORROW...ANTICIPATING
THAT THERE WILL BE SOME RESIDUAL BOUNDARIES LEFT OVER IN THE MIX.
A LESS-WORKED OVER SOUTHERN CWA AIR MASS...WITH POSSIBLE LEFT-OVER
WEDNESDAY SMALL SCALE BOUNDARIES (AND MAYBE SOME ASSISTANCE FROM
THE LOCAL BREEZE?) WILL KEEP CHANCE POPS IN PLAY CLOSER TO THE
COAST THURSDAY INTO FRIDAY. A MUCH DRIER AIR MASS FILTERING IN
ALONG THE WESTERN LEG OF A EASTERN-BASED MID-UPPER TROUGH AXIS
WILL COME OVER US DURING THE WEEKEND...SUBSTANTIALLY LOWERING
RAIN CHANCES.
THE EXTENDED SHOWS NOT MUCH IN THE WAY OF ANY DISCERNIBLE WEATHER
FEATURE THAT WILL INCREASE RAIN CHANCES BEYOND THE LOCAL SCALE
BREEZES. IF ANYTHING...RIDGING TAKES MORE OF A GRIP AND MID-LEVELS
ARE MODELED TO WARM BACK UP INTO THE LOWER 20S BY THIS TIME NEXT
WEEK. AS HAS BEEN THE CASE THESE PAST FEW DAYS...THE BAY OF CAMPECHE
HAS REMAINED SOMEWHAT ACTIVE...WITH THE NWP SUITE MAINTAINING
LOWERING PRESSURES AND A GREATER THAN 2 INCH PW AIR MASS. CENTRAL
GULF SHEAR REMAINS STOUT (30 KTS BETWEEN THE TWO UPPER RIDGES) SO
NOT TOO WORRIED WITH ANY CLOSED-OFF CIRCULATION MOVING TOO FAR
NORTH OF THE BAY. 31
MARINE...
A RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP MAINLY LIGHT ONSHORE WINDS AND LOW SEAS IN PLACE THROUGH THE
MIDDLE OF THE WEEK. A WEAK FRONT IS STILL EXPECTED TO APPROACH THE
COAST FROM THE NORTH AND NORTHEAST ON WEDNESDAY NIGHT AND THURSDAY.
THIS BOUNDARY COULD BRING THE AREA A BRIEF PERIOD OF OFFSHORE WINDS.
A WEAK TROUGH OF LOW PRESSURE OVER THE CENTRAL GULF WILL MAINTAIN E-NE
WINDS THROUGH SUNDAY. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 102 76 95 73 95 / 10 20 40 20 20
HOUSTON (IAH) 99 78 96 76 93 / 10 20 30 30 40
GALVESTON (GLS) 94 83 91 81 90 / 10 10 20 40 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...23
AVIATION/MARINE...45
AREA FORECAST DISCUSSION...UPDATED
NWS TUCSON AZ
555 AM MST WED AUG 14 2013
.SYNOPSIS...INCREASING MOISTURE WILL PROVIDE GREATER COVERAGE OF
SHOWERS AND THUNDERSTORMS STARTING TODAY AND CONTINUING INTO EARLY
NEXT WEEK. OTHERWISE...STRONG HIGH PRESSURE ALOFT WILL RESULT IN
ABOVE NORMAL DAYTIME TEMPERATURES ACROSS MUCH OF THE AREA THROUGH
THIS WEEKEND.
&&
.UPDATE...THE OFFICIAL FORECAST WAS UPDATED TO REMOVE THE PREVIOUS
DEPICTION OF ISOLATED TO SCATTERED SHOWERS/TSTMS ACROSS SOUTH
CENTRAL PINAL COUNTY THRU 8 AM MST THIS MORNING...AND TO INSERT A
SLIGHT CHANCE OF SHOWERS/TSTMS IN NEAR THE INTERNATIONAL BORDER
ADJACENT SOUTH CENTRAL PIMA COUNTY THRU THE REST OF THIS MORNING.
THE HIGHER TERRAIN EAST OF TUCSON SHOULD EXPERIENCE SHOWER/TSTM
DEVELOPMENT AROUND 18Z-19Z.
&&
.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED 30-40 DBZ ECHOES OVER
SOUTH-CENTRAL COCHISE COUNTY AT 0905Z. OTHER PRECIP ECHOES WERE JUST
SOUTH OF THE INTERNATIONAL BORDER ADJACENT SWRN COCHISE/ERN SANTA
CRUZ COUNTIES. MESOSCALE CONVECTIVE SYSTEM DECAYING ACROSS NORTHERN
AND CENTRAL SONORA AT THIS TIME...WITH CLOUD TOPS GENERALLY WARMING
DURING THE PAST 2-3 HOURS. BASED ON RADAR TRENDS AS WELL AS THE
PROXIMITY OF THIS WEAKENING SYSTEM TO SE AZ...HAVE OPTED FOR
ISOLATED SHOWERS/TSTMS THIS MORNING ACROSS SWRN COCHISE COUNTY AND
MUCH OF SANTA CRUZ COUNTY. ISOLATED SHOWERS/TSTMS SHOULD ALSO
DEVELOP ACROSS THE WHITE MOUNTAINS OF NRN GREENLEE/GRAHAM COUNTIES
BY LATE MORNING AS PER SEVERAL RUC HRRR SOLUTIONS.
OTHERWISE...POPS WERE TRENDED UPWARD FOR THIS AFTERNOON AND THIS
EVENING BASED ON THE 14/00Z NAM/GFS/ECMWF SOLUTIONS. THUS...
SCATTERED SHOWERS/TSTMS ARE EXPECTED TO OCCUR THIS AFTERNOON AND
THIS EVENING FROM TUCSON EWD/SWD WITH LESSER CHANCES OF PRECIP NORTH
AND WEST OF TUCSON. FOR LATE TONIGHT...HAVE NOTED THAT THE GFS
CONTINUES THE POTENTIAL FOR AT LEAST ISOLATED SHOWERS/TSTMS ACROSS
MUCH OF THE AREA VERSUS THE NAM. FOR NOW HAVE LIMITED A SLIGHT
CHANCE OF SHOWERS/TSTMS LATE TONIGHT ACROSS COCHISE/SANTA CRUZ
COUNTIES WITH DRY CONDITIONS ELSEWHERE. HOWEVER...CONFIDENCE IS LOW
IN THIS SCENARIO.
THUR-SAT...
14/00Z GFS/ECMWF WERE SIMILAR WITH DEPICTING 594 DM HIGH TO BE
CENTERED OVER SE AZ THUR. UPPER RIDGE IS THEN PROGGED TO AMPLIFY
OVER THE SWRN CONUS/ROCKIES FRI-SAT. MOISTURE IS ALSO PROGGED TO
INCREASE ACROSS THIS FORECAST AREA. ALTHOUGH WARMER MID-LEVEL TEMPS
MAY LIMIT CONVECTIVE DEVELOPMENT SOMEWHAT...MOISTURE SHOULD STILL BE
SUFFICIENT TO JUSTIFY SCATTERED AFTERNOON AND EVENING SHOWERS/TSTMS
EAST AND SOUTH OF TUCSON. ISOLATED AFTERNOON AND EVENING SHOWERS/
TSTMS WILL PREVAIL FROM TUCSON WWD/NWWD.
SUN-TUE...
THERE CONTINUED TO BE DIFFERENCES BETWEEN THE GFS/ECMWF REGARDING
THE UPPER LEVEL PATTERN OVER THE WRN CONUS THIS PERIOD. THE ECMWF
DEPICTED THE UPPER HIGH TO FLATTEN SUN AS A SHORTWAVE TROUGH MOVES
NORTH OF THE AREA. UPPER HIGH IS THEN PROGGED TO AMPLIFY OVER THE
AREA MON-TUE. MEANWHILE...THE GFS MAINTAINED THE UPPER HIGH OVER
ARIZONA SUN-TUE AS THE CLOSED LOW INITIALLY NEAR THE NRN CALIFORNIA
COAST FILLS AND EJECTS NEWD INTO THE PACIFIC NW. THE UPSHOT FOR SE
AZ...MOISTURE SHOULD STILL BE SUFFICIENT FOR ISOLATED-SCATTERED
AFTERNOON AND EVENING SHOWERS/TSTMS MAINLY FROM TUCSON EWD/SWD EARLY
NEXT WEEK.
HIGH TEMPS TODAY-TUE WILL GENERALLY BE ABOUT 3-8 DEGS F ABOVE
NORMAL. THE FORECAST HIGH TEMP AT TUCSON INTERNATIONAL AIRPORT TODAY
OF 105 DEGS...IF ACHIEVED...WILL BE WITHIN ONE DEGREE OF THE RECORD
HIGH TEMP FOR THIS DATE (106 DEGS SET IN 2012...1994...AND 1988).
&&
.AVIATION...VALID THRU 15/12Z. SCT080-120 SCT-BKN300. ISOLD -SHRA
NEAR THE MEXICO BORDER THIS MORNING. THEN SCT TSRA DEVELOPING AFTER
14/17Z S AND E OF KCGZ WITH MVFR CONDITIONS AND STRONG OUTFLOW WINDS
NEAR STORMS. OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS
WITH NORMAL DIURNAL DIRECTION CHANGES. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THUNDERSTORMS JUST SOUTH OF THE BORDER WILL HELP TO
INCREASE MOISTURE ACROSS SE AZ TODAY WITH A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS NEAR THE INTERNATIONAL BORDER THIS MORNING AND A
GREATER THREAT OF SHOWERS AND THUNDERSTORMS ACROSS MOST OF THE AREA
THIS AFTERNOON AND EVENING. THE INCREASE IN MOISTURE WILL ALSO BOOST
THE RH VALUES A BIT...ESPECIALLY THE OVERNIGHT RECOVERIES. FROM
THURSDAY ONWARD...UPPER LEVEL HIGH PRESSURE WILL BE OVER THE REGION
BUT THERE WILL BE ENOUGH MOISTURE TO GENERATE ISOLATED TO SCT
AFTERNOON AND EVENING CONVECTION EACH DAY. OUTSIDE OF THUNDERSTORM
WINDS...NORMAL DIURNAL WIND TRENDS ARE EXPECTED THROUGH THE
WEEKEND...WITH OCCASIONAL GUSTS DURING THE MID TO LATE AFTERNOON
HOURS DUE TO STRONG DAYTIME HEATING.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION...UPDATED
NWS TUCSON AZ
410 AM MST WED AUG 14 2013
.SYNOPSIS...INCREASING MOISTURE WILL PROVIDE GREATER COVERAGE OF
SHOWERS AND THUNDERSTORMS STARTING TODAY AND CONTINUING INTO EARLY
NEXT WEEK. OTHERWISE...STRONG HIGH PRESSURE ALOFT WILL RESULT IN
ABOVE NORMAL DAYTIME TEMPERATURES ACROSS MUCH OF THE AREA THROUGH
THIS WEEKEND.
&&
.UPDATE...THE OFFICIAL FORECAST WAS UPDATED TO INCLUDED ISOLATED TO
SCATTERED SHOWERS/TSTMS ACROSS SOUTH CENTRAL PINAL COUNTY NW OF
TUCSON THRU 14/15Z (8 AM MST). 14/08Z RUC HRRR AND 14/06Z NAM
PERFORMED EXTREMELY POORLY WITH THIS ACTIVITY. THUS...UPDATE BASED
PRIMARILY ON RADAR TRENDS. OTHER PRECIP ECHOES WITH LIGHTNING
STRIKES DETECTED WERE JUST SOUTH OF THE INTERNATIONAL BORDER
ADJACENT SANTA CRUZ COUNTY.
&&
.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED 30-40 DBZ ECHOES OVER
SOUTH-CENTRAL COCHISE COUNTY AT 0905Z. OTHER PRECIP ECHOES WERE JUST
SOUTH OF THE INTERNATIONAL BORDER ADJACENT SWRN COCHISE/ERN SANTA
CRUZ COUNTIES. MESOSCALE CONVECTIVE SYSTEM DECAYING ACROSS NORTHERN
AND CENTRAL SONORA AT THIS TIME...WITH CLOUD TOPS GENERALLY WARMING
DURING THE PAST 2-3 HOURS. BASED ON RADAR TRENDS AS WELL AS THE
PROXIMITY OF THIS WEAKENING SYSTEM TO SE AZ...HAVE OPTED FOR
ISOLATED SHOWERS/TSTMS THIS MORNING ACROSS SWRN COCHISE COUNTY AND
MUCH OF SANTA CRUZ COUNTY. ISOLATED SHOWERS/TSTMS SHOULD ALSO
DEVELOP ACROSS THE WHITE MOUNTAINS OF NRN GREENLEE/GRAHAM COUNTIES
BY LATE MORNING AS PER SEVERAL RUC HRRR SOLUTIONS.
OTHERWISE...POPS WERE TRENDED UPWARD FOR THIS AFTERNOON AND THIS
EVENING BASED ON THE 14/00Z NAM/GFS/ECMWF SOLUTIONS. THUS...
SCATTERED SHOWERS/TSTMS ARE EXPECTED TO OCCUR THIS AFTERNOON AND
THIS EVENING FROM TUCSON EWD/SWD WITH LESSER CHANCES OF PRECIP NORTH
AND WEST OF TUCSON. FOR LATE TONIGHT...HAVE NOTED THAT THE GFS
CONTINUES THE POTENTIAL FOR AT LEAST ISOLATED SHOWERS/TSTMS ACROSS
MUCH OF THE AREA VERSUS THE NAM. FOR NOW HAVE LIMITED A SLIGHT
CHANCE OF SHOWERS/TSTMS LATE TONIGHT ACROSS COCHISE/SANTA CRUZ
COUNTIES WITH DRY CONDITIONS ELSEWHERE. HOWEVER...CONFIDENCE IS LOW
IN THIS SCENARIO.
THUR-SAT...
14/00Z GFS/ECMWF WERE SIMILAR WITH DEPICTING 594 DM HIGH TO BE
CENTERED OVER SE AZ THUR. UPPER RIDGE IS THEN PROGGED TO AMPLIFY
OVER THE SWRN CONUS/ROCKIES FRI-SAT. MOISTURE IS ALSO PROGGED TO
INCREASE ACROSS THIS FORECAST AREA. ALTHOUGH WARMER MID-LEVEL TEMPS
MAY LIMIT CONVECTIVE DEVELOPMENT SOMEWHAT...MOISTURE SHOULD STILL BE
SUFFICIENT TO JUSTIFY SCATTERED AFTERNOON AND EVENING SHOWERS/TSTMS
EAST AND SOUTH OF TUCSON. ISOLATED AFTERNOON AND EVENING SHOWERS/
TSTMS WILL PREVAIL FROM TUCSON WWD/NWWD.
SUN-TUE...
THERE CONTINUED TO BE DIFFERENCES BETWEEN THE GFS/ECMWF REGARDING
THE UPPER LEVEL PATTERN OVER THE WRN CONUS THIS PERIOD. THE ECMWF
DEPICTED THE UPPER HIGH TO FLATTEN SUN AS A SHORTWAVE TROUGH MOVES
NORTH OF THE AREA. UPPER HIGH IS THEN PROGGED TO AMPLIFY OVER THE
AREA MON-TUE. MEANWHILE...THE GFS MAINTAINED THE UPPER HIGH OVER
ARIZONA SUN-TUE AS THE CLOSED LOW INITIALLY NEAR THE NRN CALIFORNIA
COAST FILLS AND EJECTS NEWD INTO THE PACIFIC NW. THE UPSHOT FOR SE
AZ...MOISTURE SHOULD STILL BE SUFFICIENT FOR ISOLATED-SCATTERED
AFTERNOON AND EVENING SHOWERS/TSTMS MAINLY FROM TUCSON EWD/SWD EARLY
NEXT WEEK.
HIGH TEMPS TODAY-TUE WILL GENERALLY BE ABOUT 3-8 DEGS F ABOVE
NORMAL. THE FORECAST HIGH TEMP AT TUCSON INTERNATIONAL AIRPORT TODAY
OF 105 DEGS...IF ACHIEVED...WILL BE WITHIN ONE DEGREE OF THE RECORD
HIGH TEMP FOR THIS DATE (106 DEGS SET IN 2012...1994...AND 1988).
&&
.AVIATION...VALID THRU 15/12Z. SCT080-120 SCT-BKN300. ISOLD -SHRA
NEAR THE MEXICO BORDER THIS MORNING. THEN SCT TSRA DEVELOPING AFTER
14/17Z S AND E OF KCGZ WITH MVFR CONDITIONS AND STRONG OUTFLOW WINDS
NEAR STORMS. OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS
WITH NORMAL DIURNAL DIRECTION CHANGES. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THUNDERSTORMS JUST SOUTH OF THE BORDER WILL HELP TO
INCREASE MOISTURE ACROSS SE AZ TODAY WITH A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS NEAR THE INTERNATIONAL BORDER THIS MORNING AND A
GREATER THREAT OF SHOWERS AND THUNDERSTORMS ACROSS MOST OF THE AREA
THIS AFTERNOON AND EVENING. THE INCREASE IN MOISTURE WILL ALSO BOOST
THE RH VALUES A BIT...ESPECIALLY THE OVERNIGHT RECOVERIES. FROM
THURSDAY ONWARD...UPPER LEVEL HIGH PRESSURE WILL BE OVER THE REGION
BUT THERE WILL BE ENOUGH MOISTURE TO GENERATE ISOLATED TO SCT
AFTERNOON AND EVENING CONVECTION EACH DAY. OUTSIDE OF THUNDERSTORM
WINDS...NORMAL DIURNAL WIND TRENDS ARE EXPECTED THROUGH THE
WEEKEND...WITH OCCASIONAL GUSTS DURING THE MID TO LATE AFTERNOON
HOURS DUE TO STRONG DAYTIME HEATING.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION
NWS PUEBLO CO
503 AM MDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM MDT WED AUG 14 2013
...DRIER AIRMASS MAKING PROGRESS EASTWARD TODAY...POTENTIAL FOR
STRONG STORMS OUT EAST THIS AFTERNOON...
SHORTWAVE MOVING DOWN EASTERN PERIPHERY OF THE UPPER RIDGE IS
KEEPING SCATTERED THUNDERSTORMS GOING ACROSS NORTHEAST/EAST CENTRAL
CO AS LOW LEVEL JET CONTINUES TO INCREASE ACROSS THE FAR EASTERN
PLAINS. KIOWA COUNTY IS MOST LIKELY TO BE CLIPPED BY THESE LATER
THIS MORNING AND FOLLOWED THE HRRR FOR POPS IN THE SHORT TERM AS IT
APPEARS TO BE THE MODEL HANDLING CURRENT CONVECTION BEST.
THUNDERSTORMS SHOULD DIMINISH OUT EAST LATER THIS MORNING.
MEANWHILE...DRIER AIRMASS OUT WEST WILL BE ADVANCING EASTWARD TODAY
WITH SHORT RANGE HIGH RES MODELS SHOWING DEW POINTS ACROSS THE
MOUNTAINS FALLING OFF INTO THE 20S AND 30S IN THE AFTERNOON. LCLS
RISE SUBSTANTIALLY AS A RESULT...AND WITH MORE INVERTED V SOUNDINGS
EXPECT EVAPORATION BELOW CLOUD BASES TO REDUCE PCPN EFFICIENCIES OF
THUNDERSTORMS SOME. HOWEVER...ERRATIC GUSTY WINDS WILL BECOME MORE
OF A THREAT AS A RESULT. MODELS STILL SHOW ENOUGH MOISTURE AND WEAK
FORCING MOVING THROUGH THE RIDGE ASSOC WITH UPPER LEVEL JET FOR
MAINLY ISOLATED AFTERNOON THUNDERSTORMS OUT WEST...WITH SCATTERED
THUNDERSTORMS ACROSS THE SE MTS/PLAINS DURING THE AFTERNOON. BUT
GIVEN THE LOWER THREAT FOR HEAVY RAINFALL...WILL NOT HOIST A FLASH
FLOOD WATCH FOR THE BURN SCARS IN EL PASO/TELLER COUNTIES. OF
COURSE...WALDO CANYON WILL NOT BE ENTIRELY OUT OF THE WOODS AS EVEN
WITH THE DRIER AIRMASS A QUICK .50 TO .75 OF RAIN WITH A STRONGER
STORM IS STILL POSSIBLE. BUT THIS LOOKS LIKE AN OUTLIER POSSIBILITY
FOR TODAY AND MORE LIKELY TO OCCUR FARTHER EAST WHERE GRADIENT OF
HIGHER DEW POINTS WILL BE LURKING. MEANWHILE...SFC DEW POINTS WILL
BE SLOWER TO DECREASE OUT ACROSS THE EASTERN PLAINS...AND NAM12
SHOWS AN AXIS OF 1500+ J/KG OF CAPE OUT OVER THE EASTERN PLAINS
OF KIOWA...BACA...BENT...AND PROWERS COUNTIES DURING THE LATE
AFTERNOON. DEEP LAYER SHEARS WILL BE RUNNING AROUND 35-40
KTS...SUFFICIENT FOR ONE OR TWO STRONG TO SEVERE THUNDERSTORMS.
LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY STORM THREATS AND
SPC HAS AREA OUTLOOKED UNDER A SEE TEXT. THUNDERSTORMS SHOULD
DIMINISH AFTER MIDNIGHT WITH LACK OF FORCING AND AXIS OF LOW LEVEL
JET PULLING AWAY TO THE EAST.
OTHERWISE...TEMPERATURES SHOULD BE A LITTLE WARMER TODAY FOR ALL
AREAS...WITH WITH DRIER SFC DEW POINTS OUT WEST...STARTING TO SEE A
RETURN OF LOWS IN THE 30S FOR SOME OF THE SPOTTY VALLEY LOCATIONS
DUE TO GOOD RADIATIONAL COOLING. LOWS ACROSS THE PLAINS WILL LIKELY
STAY IN THE 50S AND 60S WITH LEE TROFFING AND AXIS OF HIGHER DEW
POINTS HELPING TO KEEP MINS UP. -KT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 459 AM MDT WED AUG 14 2013
METEOROLOGICAL CHALLENGES DURING THE LONGER TERM INCLUDE WARMER
TEMPERATURES...POTENTIAL STRONG TO SEVERE THUNDERSTORMS OVER FAR
EASTERN SECTIONS THURSDAY AND POPS.
IT STILL APPEARS THAT DRIER AND WARMER CONDITIONS WILL DEVELOP
OVER THE MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO THE
WEEKEND AS UPPER RIDGING BUILDS INTO THE FOUR CORNERS REGION BY THIS
WEEKEND. ALSO...LATEST PRECIPITABLE WATER VALUE PROJECTIONS DROP
TO BETWEEN 0.50 AND 0.70 INCHES OVER THE INTERSTATE 25 CORRIDOR
DURING THIS TIME-FRAME.
STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO DEVELOP OVER
PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS THURSDAY AS
PROJECTED LOCALIZED CAPES AND LIS NEARING 2000 J/KG AND -7C
RESPECTIVELY INTERACT WITH 0 TO 6 KM BULK SHEARS AROUND 40 KNOTS.
WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
ARE STILL ANTICIPATED OVER THE MAJORITY OF THE CWFA FROM THURSDAY
INTO EARLY SUNDAY. EVEN THOUGH RATHER UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM DIRECTLY
IMPACTS A BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY SHOULD THEN BE
NOTED...INITIALLY OVER WESTERN SECTIONS LATER SUNDAY AND THEN
CONTINUE INTO NEXT TUESDAY AS A NORTHERLY SURFACE ATTEMPTS TO
MOVE ACROSS EASTERN SECTIONS MONDAY AND ATMOSPHERIC MOISTURE
VALUES INCREASE. FORECAST MODEL SOUNDINGS PROJECT THAT
PRECIPITABLE WATER VALUES OVER THE INTERSTATE 25 CORRIDOR
INCREASE TO AROUND ONE INCH AT TIMES BY EARLY NEXT WEEK.
AT THIS TIME...IT STILL APPEARS THAT THE HIGHEST POTENTIAL FOR
LOCALIZED HEAVY RAIN AND ASSOCIATED FLASH FLOODING
CONCERNS(ESPECIALLY OVER THE AREA BURN SCARS) WILL BE POSSIBLE BY
NEXT MONDAY AND TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR
CLOSELY.
ABOVE SEASONAL AVERAGE MID-AUGUST MAXIMUM TEMPERATURES SHOULD BE
EXPERIENCED OVER THE MAJORITY OF THE FORECAST DISTRICT FROM
THURSDAY INTO NEXT TUESDAY WITH THE WARMEST CONDITIONS ANTICIPATED
THIS WEEKEND AS 700 MB TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB
TO AROUND 18C.
MAXIMUM TEMPERATURES THIS WEEKEND OVER MANY SECTIONS OF THE
SOUTHEASTERN COLORADO PLAINS SHOULD REACH WELL INTO THE 90S THIS
WEEKEND. FINALLY...AS HAS BEEN THE CASE DURING THE PAST SEVERAL
DAYS...GENERALLY LIGHT GRADIENT WINDS SHOULD CONTINUE FROM
THURSDAY INTO NEXT TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 459 AM MDT WED AUG 14 2013
THREAT OF SOME MVFR STRATUS EXISTS ACROSS THE I-25 CORRIDOR THIS
MORNING AS WELL AS SOME PATCHY FOG ACROSS EL PASO COUNTY WHERE RAINFALL
OCCURRED YESTERDAY. THIS COULD AFFECT THE TERMINALS THIS MORNING BUT
SO FAR SATELLITE TRENDS HAVE KEPT STRATUS AND FOG WELL TO THE EAST
AROUND KLAA. PLAN TO KEEP A SCATTERED MVFR LAYER IN THE TAFS FOR
KCOS AND KPUB UNLESS TRENDS SUGGEST OTHERWISE. OTHERWISE...VFR
CONDITIONS EXPECTED THROUGH TODAY WITH ISOLATED TO SCATTERED
THUNDERSTORMS DEVELOPING OVER THE MOUNTAINS DURING THE AFTERNOON
BEFORE DRIFTING EASTWARD ACROSS THE PLAINS DURING THE LATE AFTERNOON
AND EVENING HOURS. LOCAL MVFR CIGS/VIS WILL BE POSSIBLE WITH
THUNDERSTORMS...PARTICULARLY TO THE EAST OF KLHX WHERE GREATER LOW
LEVEL MOISTURE WILL LINGER. TAF SITES HAVE MUCH LOWER CHANCE TODAY
OF BEING IMPACTED BY VCTS...THOUGH IF TS DEVELOPS NEARBY...GUSTY
OUTFLOW WINDS TO 40 KTS WILL BE POSSIBLE. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1036 AM EDT WED AUG 14 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL CROSS THE REGION TODAY AND WILL PUSH
OFFSHORE THIS EVENING. HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND
TONIGHT THROUGH THURSDAY. A WEAK COLD FRONT WILL SETTLE INTO
NORTHERN NEW ENGLAND ON FRIDAY AS HIGH PRESSURE HOLDS SOUTH OF NEW
ENGLAND. HIGH PRESSURE WILL REMAIN IN PLACE SOUTH OF THE REGION
SUNDAY AND MONDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...COLD FNT IS ALIGNED ALONG SWRN ME COAST UP THROUGH THE
CAPITAL DISTRICT ATTM. PRIMARY S/WV TROF CONTINUES TO SPIN THRU
THE ST. LAWRENCE VALLEY...WHILE SECONDARY LOBE CROSSES THE
ADIRONDACKS. THIS UPPER TROF WILL SWING ACROSS NRN NEW ENGLAND
TODAY...PROVIDING THE LIFT FOR SCT SHRA AND TSTMS. COLD AIR ALOFT
WILL PROVIDE AN IDEAL SITUATION FOR SMALL HAIL IN ANY OF THE
STRONGER STORMS. HRRR CONTINUES TO ADVERTISE A BAND OF CONVECTION
FORMING ALONG INTERIOR WRN ME...AND SWEEPING TOWARDS THE COAST.
THIS WILL BE THE MOST LIKELY AREA FOR STRONGER STORMS AND HAIL.
PREVIOUS DISCUSSION...
A STRONG SHORT WAVE TROUGH WILL MOVE ACROSS NORTHERN NEW ENGLAND
TODAY. AT THE SURFACE...LOW PRESSURE WILL HEAD UP INTO NEW
BRUNSWICK LATER THIS MORNING WITH A TRAILING COLD FRONT HUGGING
THE MAINE COAST UNTIL IT PUSHES OFF SHORE EARLY AFTERNOON. SHOWERS
AND POTENTIALLY A FEW THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE
VICINITY OF THIS FRONTAL BOUNDARY...WITH THE BEST CHANCES ON THE
MID COAST OF MAINE AND NORTHWARD.
OTHERWISE...COLD MID LEVEL AIR TO THE TUNE TO -17 TO -20C AT 500MB
WILL ADVECT INTO THE REGION. THIS WILL DECREASE STABILITY AND
LIKELY AID IN THE DEVELOPMENT OF AT LEAST WDLY SCT SHOWERS
ELSEWHERE...ESPECIALLY IN THE MOUNTAINS. HOWEVER...A GOOD DEAL OF
SUN SHOULD BE SEEN TODAY AFTER THE EARLY MORNING STRATUS AND FOG
BURNS OFF.
WESTERLY WINDS WILL BECOME GUSTY THIS AFTERNOON IN THE WAKE OF THE
FRONT...WITH A FEW GUSTS AROUND 25 MPH LIKELY. TEMPERATURES WILL
HOLD IN THE 60S IN THE MOUNTAINS...WITH 70S ELSEWHERE.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
BREEZY CAA REGIME TONIGHT WITH MOSTLY CLEAR SKIES. HOWEVER...MOIST
CYCLONIC FLOW SHOULD KEEP THE NRN NH AND WRN ME MOUNTAINS IN A
FAIR AMOUNT OF CLOUDS. ANOTHER SHORT WAVE THROUGH APPROACHES
THURSDAY BUT ANY SHOWER ACTIVITY SHOULD REMAIN JUST NORTH OF THE
BORDER IN QUEBEC.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
FAIRLY QUIET IN THE MID TERM AND EXTENDED FORECAST AS HIGH
PRESSURE BUILDS SOUTH OF NEW ENGLAND THURSDAY NIGHT AND FRIDAY. A
WEAK BACKDOOR COLD FRONT WILL DIP INTO NORTHERN NEW ENGLAND ON
FRIDAY BUT SHOULD NOT RESULT IN MUCH MORE THAN A FEW PASSING
CLOUDS. AFTER SOME CHILLY OVERNIGHT LOWS THURSDAY NIGHT SHOULD SEE
TEMPS REBOUND INTO THE LOWER TO MID 70S IN THE NORTH AND UPPER 70S
TO LOWER 80S IN THE SOUTH.
HIGH PRESSURE WILL REMAIN ANCHORED SOUTH OF NEW ENGLAND THROUGH THE
WEEKEND PROVIDING MOSTLY SUNNY SKIES AND SEASONABLE TEMPS. WILL SEE
HIGHS BOTH DAYS SIMILAR TO FRIDAY WITH A SLIGHT MODERATION IN TEMPS
ON SUNDAY AS WARMER AIR IS TRANSPORTED INTO THE THE REGION FROM THE
WEST.
HIGH PRESSURE WILL REMAIN IN CONTROL MONDAY AND TUESDAY AND WILL
BEGIN PUMPING WARMER AND MORE HUMID AIR BACK INTO THE REGION. BY
TUESDAY HIGHS WILL TOP OUT IN THE LOWER TO MID MID 80S ACROSS MUCH
OF THE FORECAST AREA ASIDE FROM MID COAST MAINE WERE AN ONSHORE
BREEZE WILL HOLD HIGHS IN THE 70S. A COLD FRONT APPROACHING FROM THE
NORTHWEST WILL BRING INCREASING CLOUDS AND A CHANCE OF SHOWERS AND
THUNDERSTORMS TO NORTHERN ZONES IN THE AFTERNOON.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...IFR OR LOWER CONDITIONS IS STRATUS AND FOG EARLY THIS
MORNING WILL GIVE WAY TO VFR CONDITIONS DURING THE MORNING HOURS.
A FEW SHOWERS AND POTENTIALLY ISOLD THUNDERSTORMS WILL BE
POSSIBLE...ON THE MID COAST OF MAINE. OTHERWISE...GUSTY NW WINDS
WILL KICK IN THIS AFTERNOON...WITH A FEW GUSTS AROUND 25 KT
LIKELY. VFR CONDITIONS ARE EXPECTED TONIGHT AND THURSDAY.
LONG TERM...VFR THURSDAY NIGHT THROUGH SUNDAY.
&&
.MARINE...
SHORT TERM...SCA HOISTED FOR ALL WATERS FOR THIS AFTERNOON AND
EVENING AS LOW PRESSURE STRENGTHENS TO OUR NORTHEAST. A STRONG CAA
PATTERN WILL LIKELY BRING 25 KT GUSTS TO THE WATERS THIS AFTERNOON
AND EVENING. WITH THE OFFSHORE FLOW IN PLACE...SEAS WILL NOT BE
MUCH OF AN ISSUE ALTHOUGH A FEW 5 FOOTERS WILL BE POSSIBLE ON THE
OUTER WATERS.
LONG TERM...NO PROBLEMS EXPECTED.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT EDT
TONIGHT FOR ANZ150>154.
&&
$$
NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS CARIBOU ME
630 AM EDT WED AUG 14 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK FROM THE SAINT JOHN VALLEY TODAY INTO GULF OF
SAINT LAWRENCE TONIGHT...BRINGING A COLD FRONT ACROSS THE REGION ALONG
WITH ADDITIONAL SHOWERS AND POSSIBLE THUNDERSTORMS. ANOTHER COLD FRONT
FROM NORTHERN CANADA WILL APPROACH LATE THURSDAY AND THEN BECOME
STATIONARY ACROSS FAR NORTHERN PORTIONS OF THE REGION ON FRIDAY. HIGH
PRESSURE WITH FAIR CONDITIONS WILL RETURN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...THE PREVIOUS FORECAST STILL LOOKS PRETTY MUCH ON
TRACK. MUCH OF THE SHOWER ACTIVITY HAS ENDED ACROSS THE FORECAST
AREA EARLY THIS MORNING, SO PULLED BACK POPS A BIT FOR THE NEXT
FEW HOURS. THE LATEST MODEL GUIDANCE INCLUDING THE HRRR AND
RUC/RAP STILL INDICATE SHOWERS WILL REDEVELOP BY MID MORNING.
OTHERWISE, NO SIGNIFICANT CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...
THE CONCERN FOR TODAY IS THE POTENTIAL FOR STRONG STORMS WITH
SMALL HAIL AND GUSTY WINDS.
THE UPPER TROUGH THAT IS CURRENTLY POSITIONED OVER EASTERN ONTARIO
WILL DEEPEN AS IT LIFTS NORTHEASTWARD TODAY. MEANWHILE, THE SURFACE
LOW WILL SLIDE ACROSS NORTHERN MAINE, DRAGGING A SURFACE
BOUNDARY/COLD FRONT THROUGH THE FORECAST AREA AS IT DOES SO. WITH
THE COLD POOL ASSOCIATED WITH THE UPPER LOW MOVING IN OVERHEAD,
LAPSE RATES WILL STEEPEN TO 6-7 C/KM WITH LIFTED INDICES OF -4 TO
-5C. FREEZING LEVELS WILL DROP TO AROUND 9 KFT, ENHANCING THE
POTENTIAL FOR HAIL. A JET WORKING AROUND THE BOTTOM OF THE DIGGING
UPPER TROUGH WILL ALLOW FOR IMPRESSIVE SHEAR; 0-6KM BULK SHEAR
LOOKS TO REACH 40-50 KT OR BETTER. ALL THIS POINTS TO THE
POTENTIAL FOR STRONG TO POSSIBLY SEVERE STORMS THIS AFTERNOON. THE
FLY IN THE OINTMENT WILL BE SURFACE INSTABILITY. SURFACE-BASED
CAPES WILL DEPEND HEAVILY UPON HOW MUCH SUNSHINE IS ABLE TO BREAK
THROUGH THE CLOUDS. WATER VAPOR IMAGERY DOES INDICATE SOME DRIER
AIR WORKING AROUND THE SOUTHERN SIDE OF THE TROUGH, WHICH SHOULD
ALLOW FOR SKIES TO BECOME PARTLY SUNNY FOR AT LEAST THE SOUTHERN
HALF OF THE FORECAST AREA. THE QUESTION THEN BECOMES ONE OF
TIMING, AS TO HOW LONG THE ATMOSPHERE HAS TO DESTABILIZE BEFORE
THE AFOREMENTIONED BOUNDARY MOVES ACROSS THE REGION. THE LATEST
RUC/RAP, WHICH WAS FAVORED FOR ITS TIMING/PLACEMENT OF PRECIP
THROUGH THIS EVENING, SHOWS CAPES REACHING 1000+ J/KG, MAINLY
ACROSS EASTERN AND SOUTHERN AREAS AWAY FROM THE COAST. THE NAM IS
SIMILAR IN PLACEMENT BUT MORE ROBUST IN AMOUNTS, RANGING FROM
1200-1400 J/KG. MEANWHILE THE GFS IS NOT AS OPTIMISTIC AND KEEPS
CAPES BELOW 900 J/KG. LONG STORY SHORT...SCATTERED STRONG STORMS
ARE POSSIBLE THIS AFTERNOON, SOME OF WHICH MAY APPROACH SEVERE
LEVELS, MAINLY SOUTH AND EAST OF A MONTICELLO...MILLINOCKET
DOVER-FOXCROFT LINE. GIVEN THE UNCERTAINTY IN INSTABILITY,
THERE WAS NOT ENOUGH CONFIDENCE TO ADD SEVERE-TYPE WORDING TO THE
FORECAST. HOWEVER, THE ENHANCED WORDING FOR STRONG STORMS THAT WAS
INTRODUCED YESTERDAY IS STILL WARRANTED GIVEN THE ABOVE THINKING.
OPTED TO INCLUDE THE ENHANCED WORDING EVEN IN THE NORTH AND WEST,
THOUGH THE WINDOW FOR STRONG STORMS IS MUCH SMALLER THERE; CLOUD
COVER WILL BE TOUGHER TO BREAK UP IN TIME FOR ENOUGH
SUNSHINE/DESTABILIZATION PRIOR TO FRONTAL PASSAGE TO ALLOW FOR
ORGANIZED STORMS. BUT CAN`T TOTALLY RULE OUT A STRONG STORM OR
TWO.
THE FRONT WILL EXIT INTO NEW BRUNSWICK THIS EVENING, QUICKLY ENDING
THUNDERSTORM POTENTIAL FROM WEST TO EAST THROUGH THE AFTERNOON.
EXPECT THE PRECIPITATION WILL COME TO AN END BY MIDNIGHT AS DRIER
AIR RUSHES IN BEHIND THE FRONT. EXPECT SKIES WILL BECOME PARTLY TO
MOSTLY CLEAR AFTER MIDNIGHT, WITH OVERNIGHT LOWS RANGING FROM THE
MID 40S IN THE NORTH TO AROUND 50 DOWNEAST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
THU WILL BEGIN MSLY SUNNY AND BREEZY ACROSS THE FA...BUT ANOTHER
S/WV ALG WITH AN APCHG COLD FRONT WILL BRING SOME INCREASE IN
CLDNSS FOR CNTRL AND SPCLY NRN PTNS OF THE FA LATE IN THE DAY AND
EVE...WITH A SLGT CHC OF SHWRS. ANY SHWRS SHOULD DISSIPATE LATE
THU NGT. FRI WILL AGAIN BEGIN FAIR...BUT WITH THE COLD FRONT
BECOMING STATIONARY OVR NRN PTNS OF THE FA. AN UPPER LVL TROF
CROSSING THIS PTN OF THE REGION FRI AFTN WILL ACT AS A FOCUS FOR
AFTN AND ERLY EVE SHWRS OVR CNTRL AND SPCLY NRN PTNS OF THE FA
WHERE WE GO WITH CHC TO HI CHC POPS. FCST SBCAPES OF 100-200 J/KG
FOR THESE PDS DO NOT YET SUPPORT TSTMS IN THE FCST...BUT THIS WILL
NEED TO BE MONITORED. IN ANY EVENT...WITH LITTLE IN THE WAY OF
AVAILABLE LLVL MOISTURE ALG WITH FAST FORWARD MOTION...QPF WILL BE
LGT WITH THESE SHWRS. SHWRS SHOULD DISSIPATE QUICKLY AFT SUNSET
WITH THE LOSS OF DAYTIME HTG AND LOW TO MID LVL INSTABILITY AS THE
UPPER TROF QUICKLY MOVES E INTO THE MARITIMES. THIS WILL ALLOW SFC
HI PRES TO BUILD ACROSS THE FA FROM CNTRL CAN LATE FRI NGT.
BOTH HI AND LOW TEMPS WILL BE COOLER THAN SEASONAL NORMS DURG THE
SHORT RANGE...WITH THE COOLEST TEMPS ERLY SAT MORN. WE DID BACK
OFF A COUPLE OF DEG F FROM THE LOWEST TEMPS XPCTD OVR NW VLYS...
DUE TO UNCERTAINTY AS TO HOW LONG CLDNSS FROM THE DEPARTING UPPER
TROF LASTS INTO FRI EVE. WITH AN ELONGATED W-E SFC HI PRES OVR THE
REGION SAT...TEMPS SHOULD MAKE A MARKED RECOVERY FROM CHILLY LOW
TEMPS TO JUST BLO SEASONAL NORMS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AFT A COOL NGT SAT NGT...BUT NOT AS COOL AS FRI NGT...HI TEMPS
WILL BEGIN A WARMING TREND SUN...EVENTUALLY YIELDING TO ABV NORMAL
HI TEMPS AND CONTD MODERATING LOW TEMPS ERLY NEXT WEEK AS THE SFC
HI SLOWLY DRIFTS S INTO THE GULF OF ME IN RESPONSE TO SPLIT FLOW...
FLAT UPPER LVL RIDGING OVR NRN NEW ENG...ALLOWING A RETURN WSW
LLVL FLOW REGIME TO THE REGION. IN FACT... HI TEMPS WILL LIKELY
EXCEED 80 DEG OVR MOST OF THE FA MON AND TUE. THE NEXT CHC OF ANY
SHWRS/TSTMS NO EARLIER THAN LATE TUE INTO TUE NGT AS PER THE 00Z
GFS...BUT IT MUST BE POINTED OUT THAT OTHER LONG RANGE MODELS LIKE
THE 00Z ECMWF COULD HOLD OFF RNFL EVEN LONGER...CONFIDENCE ON ANY
RNFL THIS LATE IN THE FCST...AS TYPICAL...IS LOW ATTM.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: MVFR WITH LOCAL IFR LIKELY THROUGH THIS MORNING DUE TO
LOW CLOUDS AND FOG. WHILE LOW CEILINGS WILL LINGER ACROSS THE
NORTH THROUGH MUCH OF THE DAY, EXPECT VFR CONDITIONS AT THE
SOUTHERN TAF SITES AS DRIER AIR WORKS INTO THE AREA. SHOWERS WITH
SCATTERED THUNDERSTORMS WILL AFFECT THE REGION THROUGH THIS
EVENING, ENDING FROM WEST TO EAST BY 02Z TONIGHT. SKIES WILL
BECOME PARTLY TO MOSTLY CLEAR THEREAFTER, WITH PERHAPS SOME LOCAL
IFR DUE TO FOG TOWARD DAYBREAK.
SHORT TO LONG TERM: VFR ANTICIPATED THU THRU SUN...XCPT PERHAPS
VERY BRIEF MVFR CONDITIONS POSSIBLE FRI AFTN ACROSS NRN TAF SITES
IN ISOLD HEAVIER SHWRS FRI AFTN.
&&
.MARINE...
NEAR TERM: DENSE FOG WILL KEEP VISIBILITY REDUCED TO BELOW 1 SM
ACROSS THE WATERS THROUGH EARLY THIS MORNING, BUT EXPECT
CONDITIONS TO IMPROVE BY THIS AFTERNOON. ISOLATED TO SCATTERED
SHOWERS ARE POSSIBLE THIS AFTERNOON, AND AN INCREASING SOUTH WIND
WILL ALLOW SEAS TO BUILD TO 3-4 FT. HOWEVER, EXPECT CONDITIONS TO
REMAIN BELOW SMALL CRAFT ADVISORY LEVELS, SO NO HEADLINES ARE
ANTICIPATED.
SHORT TO LONG TERM: NO HDLNS ANTICIPATED FOR THESE PDS THIS
UPDATE. WE BLENDED 00Z WW3 WITH SWAN NAM FOR WV HTS...SMOOTHED
ALG THE IMMEDIATE COAST TO BRING WV HTS DOWN TO ARND 1 FT. OVR
THE OUTER WATERS...WV HTS WILL RUN 2 TO 4 FT OR LESS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
551 AM CDT WED AUG 14 2013
.UPDATED FOR 12Z AVIATION DISCUSSION...
ISSUED AT 542 AM CDT WED AUG 14 2013
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 336 AM CDT WED AUG 14 2013
AS HAS BEEN THE CASE FOR THE LAST FEW WEEKS...EARLY MORNING WATER
VAPOR IMAGERY AND 500MB HEIGHTS AND WINDS IDENTIFIED A RIDGE ACROSS
THE EASTERN SPINE OF THE CANADIAN ROCKIES...WITH A LONGWAVE TROUGH
OVER THE GREAT LAKES AND EASTERN CANADA. NORTHWEST FLOW PERSISTED
OVER THE UPPER MIDWEST...WITH A COUPLE EMBEDDED SHORTWAVES OVER THE
HIGH PLAINS. ONE OF THESE SHORTWAVES WAS THE DRIVING FORCE BEHIND AN
MCS TRACKING EASTWARD ALONG THE NE/SD BORDER. HIRES MODELS SUCH AS THE
HOPWRF AND HRRR TAKE THIS CONVECTION DOWN THE MISSOURI RIVER VALLEY
THIS MORNING AND KEEPS MN/WI FREE FROM ANY PRECIP. THIS SOLUTION
MAKES SENSE GIVEN THE SUBSIDENCE BENEATH THE NORTHWEST FLOW IN
ASSOCIATION WITH NEGATIVE VORTICITY ADVECTION THAT IS FORECAST TO
MOVE ACROSS THE REGION THIS AFTERNOON. THEREFORE EXPECT ANOTHER DAY
OF LIGHT WINDS AND A FEW AFTERNOON CLOUDS WITH BASES AROUND 6000FT.
TEMPERATURES WILL BE SIMILAR TO YESTERDAY...BUT THE THIN CIRRUS FROM
THE CONVECTION OUT WEST MAY KEEP THEM A DEGREE OR TWO COOLER THAN
TUESDAYS HIGHS...ESPECIALLY IN WESTERN MN.
LATER TONIGHT ANOTHER SHORTWAVE IS FORECAST TO MOVE ACROSS THE
MISSOURI RIVER VALLEY...AND THIS WILL PRODUCE ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...WITH DEVELOPMENT EXPECTED A LITTLE
FARTHER EAST. THEREFORE EXPECT WESTERN MN TO BE DRY FOR MOST OF THE
PERIOD...BUT DID INTRODUCE A SLIGHT CHANCE OF POPS ACROSS THE
SOUTHWEST EARLY THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 336 AM CDT WED AUG 14 2013
THE WEAK MCS FROM WEDNESDAY NIGHT WILL BE LOCATED OVER WESTERN IA
AT THE BEGINNING OF THE PERIOD. EXTENSIVE CLOUDINESS AND POSSIBLE
RAIN ACROSS IA WILL KEEP TEMPERATURES COOL THERE...WHILE MORNING
SUNSHINE SHOULD ALLOW FOR A QUICK REBOUND BACK INTO THE 70S ACROSS
MN/WI. SYNOPTIC SOUTHERLY FLOW WILL ADVECT THE COOL BOUNDARY
NORTHWARD BY AFTERNOON...WHICH COULD PRODUCE A COUPLE SHOWERS OR
STORMS ACROSS SRN MN AS THE ATMOSPHERE BECOMES WEAKLY UNSTABLE.
THERE IS A PRONOUNCED CAP BETWEEN 600-700 MB WHICH WILL LIMIT
COVERAGE TO 20-30 PCT...AND IF CLOUD COVER IS HIGHER THAN FORECAST
THE INSTABILITY MAY NEVER EVEN MATERIALIZE.
BY FRIDAY...STRONG RIDGING WILL EMERGE OVER THE WESTERN HIGH
PLAINS FROM THE ROCKIES. SOUTH/SOUTHEASTERLY FLOW AT THE SURFACE
WILL KEEP TEMPERATURES IN THE UPPER 70S/LOWER 80S LOCALLY...BUT
TEMPERATURES WILL INCH UPWARD EACH DAY AS THE RIDGE CONTINUES
BUILDING EAST. BY SATURDAY...AN IMPRESSIVE THERMAL RIDGE WILL BE
IN PLACE OVER THE WESTERN DAKOTAS. AS THE WEEKEND PROGRESSES...
AND ESPECIALLY BY EARLY NEXT WEEK...STRONGER MID AND UPPER LEVEL
FLOW WILL BECOME ESTABLISHED OVER SOUTHERN CANADA. THIS WILL BRING
THE RIDGING FURTHER EAST INTO THE UPPER MIDWEST AND MISSISSIPPI
VALLEY. 850 MB TEMPS RISE TO AROUND 20C AND 925 MB TEMPS RISE INTO
THE MID 20S C...THUS SUMMER WILL FINALLY RETURN WITH HIGHS IN THE
MID 80S TO LOWER 90S. POPS APPEAR LOW TO NIL GIVEN THE LACK OF
FORCING. ANY CHANCES WILL BE DRIVEN ON LOCAL FEATURES TOO
DIFFICULT TO PINPOINT THIS FAR OUT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 542 AM CDT WED AUG 14 2013
HIGH PRESSURE WILL REMAIN IN CONTROL WITH VFR CONDITIONS EXPECTED
THROUGHOUT. VARIABLE MORNING WINDS WILL BECOME WEST SOUTHWESTERLY
TODAY. HIGH CLOUDS WILL INCREASE TONIGHT AND SHOULD LIMIT THE FOG
POTENTIAL THURSDAY MORNING.
KMSP...
VFR CONDITIONS THROUGHOUT. LIGHT AND VARIABLE WINDS WILL GRADUALLY
TAKE ON A WEST SOUTHWESTERLY DIRECTION TODAY. LOOK FOR FLAT
CUMULUS AT AROUND 6000FT THIS AFTERNOON...WITH HIGH CLOUDS
INCREASING LATER TONIGHT.
/OUTLOOK FOR KMSP/
THU...VFR. WINDS SW AT 05KTS.
FRI...VFR WITH -SHRA/TSRA POSSIBLE. WINDS S AT 05G10KTS.
SAT...VFR. WINDS SSW AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1021 AM CDT WED AUG 14 2013
.UPDATE...
ISSUED AT 1021 AM CDT WED AUG 14 2013
MADE A FEW CHANGES TO POP/WX/SKY AND ALSO TEMPS IN THE NORTHEAST
FOR TODAY. LATEST TRENDS SHOW REMNANTS FROM THE OVERNIGHT MCS
STILL LINGERING IN THE NORTHEAST. THIS LOOKS TO BE A FAVORABLE
AREA FOR SHOWERS TO CONTINUE INTO THE EARLY AFTERNOON HOURS AS
INDICATED BY THE 12Z NAM...ALTHOUGH THE NAM IS A BIT SLOW. THIS
AFTERNOON... THUNDERSTORM CHANCES GET A LITTLE MORE NEBULOUS AS
NAM POINTS TOWARD ACTIVITY CONTINUING IN THE NORTHEAST...AND ONLY
FAVORS ISOLATED ACTIVITY IN THE FAR WEST. THE 06Z GFS KEEPS THE
WHOLE EASTERN CWA ACTIVE...AS DOES THE 09Z SREF. MADE SLIGHT
ADJUSTMENTS BASED ON LATEST TRENDS...BUT WILL CONTINUE TO EVALUATE
12Z MODEL SUITE AND EFFECTS OF MORNING CONVECTION BEFORE MAKING
MAJOR CHANGES FOR THIS AFTERNOON. WILL ALSO MONITOR FOR SEVERE
THREAT AS SHEAR LOOKS A LITTLE BETTER THAN YESTERDAY ACROSS THE
AREA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT WED AUG 14 2013
IN THE VERY NEAR TERM MESOSCALE CONVECTIVE VORTICITY (MCV) MOVING
ACROSS NORTHERN NEBRASKA. HRRR MODEL WANTS TO DEVELOP MORE
CONVECTION INTO SOUTHWEST NEBRASKA THROUGH THE EARLY MORNING BUT
RADAR TRENDS SHOWING THAT FORCING DIMINISHING OVER SOUTHWEST
NEBRASKA. HAVE CONTINUED LIKELY POPS OVER NORTH CENTRAL NEBRASKA
WITH CHANCES SLOWLY TAPERING DOWN TO SLIGHT CHANCE AS THE SYSTEM
MOVES EAST. CHANCE POPS BROUGHT BACK INTO ENTIRE FORECAST AREA
THIS AFTERNOON AS A WAVE MOVES SOUTHEAST ACROSS FORECAST AREA FROM
SOUTH DAKOTA. TEMPERATURES TODAY WILL BE SKEWED BY MCV AND CLOUD
SHIELD OVER NORTH CENTRAL NEBRASKA WITH HIGH AT ONEILL 74 DEGREES.
80S TO THE WEST AND SOUTHWEST WHERE PARTLY TO MOSTLY CLOUDY SKIES
SEEN. FAIRLY ROBUST SOUTHERLY FLOW THIS AFTERNOON WITH DEW POINTS
AROUND 60. TIMING OF WAVES WILL BE KEY TO PRECIPITATION CHANCES.
LOW LEVEL JET TONIGHT WILL HELP TO SUSTAIN CONVECTION FROM THE
AFTERNOON AND HELP TO CARRY IT ACROSS THE FORECAST AREA. COOLER
TEMPERATURES AGAIN WITH LOWS BY SUNRISE IN THE MID TO UPPER 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CDT WED AUG 14 2013
A SHORTWAVE TROUGH WILL ROTATE SOUTHEAST ACROSS THE AREA THURSDAY
ON THE EASTERN PERIPHERY OF THE ROCKIES UPPER LEVEL RIDGE.
SCATTERED AFTERNOON THUNDERSTORMS ARE POSSIBLE AS THIS FEATURE
ROTATES SOUTHEAST ACROSS THE AREA. STEEP LOW AND MID LEVEL LAPSE
RATES COMBINED WITH AMPLE MOISTURE...SHOULD YIELD MODERATE TO
LOCALLY STRONG INSTABILITY BY AFTERNOON. NORTHWEST FLOW ALOFT WILL
INCREASE...AND WHEN COMBINED WITH WEAK EAST TO SOUTHEAST FLOW AT
THE SURFACE...DECENT BULK SHEAR OF 35 TO 45 KTS WILL LIKELY
SUPPORT A FEW SOUTHEAST MOVING SUPERCELLS WITH THE POTENTIAL FOR
LARGE HAIL.
AFTER THURSDAY...THE UPPER LEVEL RIDGE WILL AMPLIFY AND BUILD
NORTHEAST OVER THE AREA...BRINGING A SPELL OF DRY WEATHER FRIDAY
THROUGH SUNDAY. TEMPERATURES WILL SLOWLY WARM DURING THIS
PERIOD...WITH HIGHS RANGING FROM THE LOWER TO MID 80S FRIDAY...TO
THE MID AND UPPER 80S SUNDAY.
EARLY NEXT WEEK THE UPPER LEVEL RIDGE REMAINS ANCHORED OVER THE
AREA. MODELS ARE TRYING TO BRING A DISTURBANCE THROUGH THE REGION
ON THE SOUTHERN FRINGES OF THE NORTHERN STREAM. CONFIDENCE IS LOW
AT THIS POINT REGARDING THE TIMING AND STRENGTH OF THIS
DISTURBANCE. HAVE KEPT ANY CHANCES FOR PRECIPITATION LOW...AND
HAVE KEPT TEMPERATURES WARM WITH THE UPPER LEVEL RIDGE IN CONTROL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 655 AM CDT WED AUG 14 2013
SOME MVFR (CEILINGS) STRATUS OVER WESTERN NEBRASKA WILL LINGER
THROUGH MID MORNING BEFORE LIFTING. THUNDERSTORMS KANW TO KONL TO
KBBW WILL CONTINUE TO MOVE EAST INTO EASTERN NEBRASKA THROUGH THE
MORNING. DRIER AIR WILL ADVECT INTO WESTERN NEBRASKA THIS
AFTERNOON AND EVENING. THUNDERSTORM CHANCES INCREASE ACROSS
WESTERN NEBRASKA THIS AFTERNOON AND EVENING WITH GENERALLY VFR
CONDITIONS PREVAILING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KNUTSVIG
SHORT TERM...POWER
LONG TERM...TAYLOR
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
655 AM CDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT WED AUG 14 2013
IN THE VERY NEAR TERM MESOSCALE CONVECTIVE VORTICITY (MCV) MOVING
ACROSS NORTHERN NEBRASKA. HRRR MODEL WANTS TO DEVELOP MORE
CONVECTION INTO SOUTHWEST NEBRASKA THROUGH THE EARLY MORNING BUT
RADAR TRENDS SHOWING THAT FORCING DIMINISHING OVER SOUTHWEST
NEBRASKA. HAVE CONTINUED LIKELY POPS OVER NORTH CENTRAL NEBRASKA
WITH CHANCES SLOWLY TAPERING DOWN TO SLIGHT CHANCE AS THE SYSTEM
MOVES EAST. CHANCE POPS BROUGHT BACK INTO ENTIRE FORECAST AREA
THIS AFTERNOON AS A WAVE MOVES SOUTHEAST ACROSS FORECAST AREA FROM
SOUTH DAKOTA. TEMPERATURES TODAY WILL BE SKEWED BY MCV AND CLOUD
SHIELD OVER NORTH CENTRAL NEBRASKA WITH HIGH AT ONEILL 74 DEGREES.
80S TO THE WEST AND SOUTHWEST WHERE PARTLY TO MOSTLY CLOUDY SKIES
SEEN. FAIRLY ROBUST SOUTHERLY FLOW THIS AFTERNOON WITH DEW POINTS
AROUND 60. TIMING OF WAVES WILL BE KEY TO PRECIPITATION CHANCES.
LOW LEVEL JET TONIGHT WILL HELP TO SUSTAIN CONVECTION FROM THE
AFTERNOON AND HELP TO CARRY IT ACROSS THE FORECAST AREA. COOLER
TEMPERATURES AGAIN WITH LOWS BY SUNRISE IN THE MID TO UPPER 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CDT WED AUG 14 2013
A SHORTWAVE TROUGH WILL ROTATE SOUTHEAST ACROSS THE AREA THURSDAY
ON THE EASTERN PERIPHERY OF THE ROCKIES UPPER LEVEL RIDGE.
SCATTERED AFTERNOON THUNDERSTORMS ARE POSSIBLE AS THIS FEATURE
ROTATES SOUTHEAST ACROSS THE AREA. STEEP LOW AND MID LEVEL LAPSE
RATES COMBINED WITH AMPLE MOISTURE...SHOULD YIELD MODERATE TO
LOCALLY STRONG INSTABILITY BY AFTERNOON. NORTHWEST FLOW ALOFT WILL
INCREASE...AND WHEN COMBINED WITH WEAK EAST TO SOUTHEAST FLOW AT
THE SURFACE...DECENT BULK SHEAR OF 35 TO 45 KTS WILL LIKELY
SUPPORT A FEW SOUTHEAST MOVING SUPERCELLS WITH THE POTENTIAL FOR
LARGE HAIL.
AFTER THURSDAY...THE UPPER LEVEL RIDGE WILL AMPLIFY AND BUILD
NORTHEAST OVER THE AREA...BRINGING A SPELL OF DRY WEATHER FRIDAY
THROUGH SUNDAY. TEMPERATURES WILL SLOWLY WARM DURING THIS
PERIOD...WITH HIGHS RANGING FROM THE LOWER TO MID 80S FRIDAY...TO
THE MID AND UPPER 80S SUNDAY.
EARLY NEXT WEEK THE UPPER LEVEL RIDGE REMAINS ANCHORED OVER THE
AREA. MODELS ARE TRYING TO BRING A DISTURBANCE THROUGH THE REGION
ON THE SOUTHERN FRINGES OF THE NORTHERN STREAM. CONFIDENCE IS LOW
AT THIS POINT REGARDING THE TIMING AND STRENGTH OF THIS
DISTURBANCE. HAVE KEPT ANY CHANCES FOR PRECIPITATION LOW...AND
HAVE KEPT TEMPERATURES WARM WITH THE UPPER LEVEL RIDGE IN CONTROL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 655 AM CDT WED AUG 14 2013
SOME MVFR (CEILINGS) STRATUS OVER WESTERN NEBRASKA WILL LINGER
THROUGH MID MORNING BEFORE LIFTING. THUNDERSTORMS KANW TO KONL TO
KBBW WILL CONTINUE TO MOVE EAST INTO EASTERN NEBRASKA THROUGH THE
MORNING. DRIER AIR WILL ADVECT INTO WESTERN NEBRASKA THIS
AFTERNOON AND EVENING. THUNDERSTORM CHANCES INCREASE ACROSS
WESTERN NEBRASKA THIS AFTERNOON AND EVENING WITH GENERALLY VFR
CONDITIONS PREVAILING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...POWER
LONG TERM...TAYLOR
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1040 AM EDT WED AUG 14 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO SINK SOUTHWARD THIS AFTERNOON AND
THEN STALL OVER SOUTHERN SOUTH CAROLINA TONIGHT THROUGH FRIDAY...
BEFORE LIFTING BACK NORTH THIS WEEKEND. THIS WILL RESULT IN
SEVERAL PERIODS OF SIGNIFICANT RAINFALL THROUGH THE UPCOMING
WEEKEND. A DRYING AND WARMING TREND IS EXPECTED NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1050 AM WEDNESDAY...THE COLD FRONT IS MAKING PROGRESS TO THE
SOUTH AND THE FRONT IS NEARING WILLIAMSBURG AND GEORGETOWN
COUNTIES AT 14 UTC. THE DEW POINTS ARE NOW IN THE UPPER 60S IN
ROBESON AND BLADEN COUNTIES AND THIS DRIER AIR WILL SLOW BUT MAKE
A BIT FARTHER PUSH TO THE SOUTH. PATCHY SHOWERS ARE BEGINNING TO
MOVE INTO THE NORTHWEST COUNTIES AND THESE WILL CONTINUE OVER THE
NEXT FEW HOURS AS THEY SPREAD EASTWARD. THE 12 UTC HRRR IS SHOWING
THE STRONGEST CONVECTION ALONG THE FRONTAL BOUNDARY WHICH WILL BE
SOUTH OF THE AREA. BUT SOME WEAKER CONVECTION IS FORECASTED TO
DEVELOP ALONG THE COASTAL COUNTIES MAINLY AFTER 18 UTC AND THE
OVER INLAND PORTIONS OF NORTHEAST SOUTH CAROLINA COUNTIES JUST
NORTH OF THE SURFACE BOARDER. TEMPERATURES WILL STRUGGLE BUT
SHOULD SETTLE OUT IN THE LOWER 80S TO NEAR 80 ESPECIALLY IF A
BREAK IN THE CLOUDS DEVELOP.
OVERNIGHT WITH THE COOLER AND DRIER AIR LOWS WILL FALL INTO THE
MID 60S NORTH OF A FLORENCE TO BURGAW LINE AND UPPER 60S TO THE
SOUTH.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...AFTER SEVERAL DAYS OF THE GUIDANCE
INSISTING THAT THE COLD FRONT WILL GET HUNG UP OVER THE LOCAL
CWA...IT NOW APPEARS IT WILL GET SHUNTED FAR ENOUGH SOUTHWARD THAT
DRIER AIR IS NOW PROGGED TO WORK INTO THE CWA...ESPECIALLY ACROSS
THE NORTHERN HALF. WHILE THE EXTREME SOUTHERN END OF THE CWA MAY
STILL GET INTO PERIODS OF HEAVY RAINFALL THURSDAY...BUT BOTH LOWER
AND UPPER ATMOSPHERIC PARAMETERS NOW LOOK LESS FAVORABLE FOR
CONVECTION AND HEAVY RAINFALL. THURSDAY WILL NOT BE A "NICE" DAY
ACROSS THE AREA...WITH LOTS OF CLOUDS AND STILL SHOWERS AROUND
THANKS TO SOME DIFFLUENCE ALOFT IN THE FRONT IN THE VICINITY...AND
TEMPS RISING ONLY TO AROUND 80...MAYBE LOW 80S FAR SOUTHERN ZONES.
LOWS THURSDAY NIGHT WILL DROP INTO THE UPPER 60S MOST LOCATIONS.
MOISTURE RETURNS FRIDAY AS THE FRONT BEGINS TO LIFT BACK ACROSS THE
AREA IN RESPONDS TO A 5H LOW CLOSING OFF ACROSS THE TN VLY AND UPPER
RIDGING OVER THE ATLANTIC OCEAN RETROGRADING BACK TOWARDS THE COAST.
THIS TURNS MUCH OF THE MID-LEVEL FLOW TO SOUTHERLY...AND ADVECTS
MORE SIGNIFICANT MOISTURE BACK INTO THE COLUMN. PWATS RISE TO OVER
TWO INCHES ONCE AGAIN...WHILE A STRONG VORT MOVES THROUGH THE TROUGH
AND OVERHEAD FRIDAY. THIS WILL CAUSE INCREASED COVERAGE OF
PRECIP...WITH RENEWED HEAVY RAIN POTENTIAL. THE BEST CHANCE WILL
AGAIN BE THE EASTERN THIRD OF THE CWA...BUT FRIDAY LOOKS LIKE IT
WILL BE AT LEAST MARGINALLY MORE ACTIVE THAN THURSDAY.
SURPRISINGLY...PRECIP TYPE ON FRIDAY COULD BE PRIMARILY SHOWERS OR
STRATIFORM RAIN AS LOW LEVEL FLOW OVERRUNS THE SLOWLY ADVANCING
FRONT. HAVE INCLUDED MENTION OF THUNDER DUE TO SOME UPPER
SUPPORT...BUT SOUNDINGS SUGGEST SOMEWHAT LIMITED INSTABILITY. TEMPS
FRIDAY WILL AGAIN BE HELD IN CHECK BY CLOUDS AND RAIN...RISING ONLY
TO AROUND 80 ACROSS THE CWA. LOWS FRIDAY NIGHT WILL BE A DEGREE OR
TWO WARMER THAN THURSDAY NIGHT AREA-WIDE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...THE EXTENDED WILL START OUT QUITE WET...BUT
A DRYING AND WARMING TREND WILL DEVELOP INTO NEXT WEEK.
CUTOFF 5H LOW ACROSS THE TN VLY AND LARGE UPPER BLOCKING RIDGE
ACROSS THE ATLANTIC OCEAN PINCHES THE AREA BETWEEN THE TWO...WITH
DEEP SOUTHERLY FLOW PERSISTING WITHIN THE COLUMN. WHILE THE WEAK
COLD/STATIONARY FRONT WILL BE LIFTING BACK ACROSS THE
AREA...TROPICAL MOISTURE IN THE GULF OF MEXICO WILL BE ADVECTED
NORTHWARD TOWARDS THE AREA. WHILE THIS IS HAPPENING...UPPER RIDGE
WILL BEGIN TO RETROGRADE STRONGLY BACK TOWARDS THE COAST. ALL
THESE TOGETHER POINT TOWARDS SATURDAY BEING VERY WET...BUT THE
HIGHEST RAINFALL TOTALS MAY BE I-95 AND WESTWARD THANKS TO THE
ADVANCING RIDGE. SUN-TUE...RIDGE MOVES EVEN FURTHER WEST AND RIDGE
AXIS IS NO PROGGED TO MAKE IT EVEN WEST OF THE COAST. THIS SHUNTS
THE BEST PRECIP FORCING WEST OF THE LOCAL AREA...AND A
DRYING/WARMING TREND WILL COMMENCE SUNDAY. SUNDAY WILL STILL
FEATURE SCATTERED TO WIDESPREAD CONVECTION...BUT LOWERING POP WITH
TEMPS RISING TO SEASONABLE OR ABOVE-CLIMO LEVELS WILL OCCUR NEXT
WEEK.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED
TODAY AND TONIGHT POTENTIALLY CREATING BRIEF PERIODS OF MVFR/IFR.
AREAS OF FOG MAY CREATE BRIEFLY REDUCED RESTRICTIONS AS WELL.
OTHERWISE EXPECT VFR.
VFR PREVAILS THIS MORNING WITH A FEW LIGHT SHOWERS PUSHING OFF
THE COAST ATTM AS A COLD FRONT CONTINUES TO DROP AND PUSH THROUGH
THE FORECAST AREA THIS MORNING. ANTICIPATE THE FRONTAL PASSAGE TO
SLOWLY PUSH THROUGH THE EARLY AFTERNOON HOURS...BECOMING STALLED
ALONG THE COAST AND ALLOWING FOR WINDS TO VEER FROM SOUTH-
SOUTHWEST TO NORTH- NORTHWEST...TO EVENTUALLY NORTHEAST BY LATER
TODAY. SUSTAINED WINDS OF AOB 12 KTS ARE ANTICIPATED...WITH GUSTS
AROUND 25 KTS POSSIBLE IN ANY STRONG THUNDERSTORMS AS CHANCES
INCREASE FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
BEHIND THE FRONT. CONFIDENCE IS LOWERED GIVEN
TIMING/LOCATION...THUS HAVE OPTED TO CONTINUE VCSH/VCTS/TEMPO
GROUPS. TONIGHT AND THROUGH THE REMAINDER OF FCST PERIOD...FCST
SOUNDINGS AND TIME-HEIGHT ANALYSIS ARE IN AGREEMENT FOR THE
POSSIBILITY OF MVFR DUE TO LOW CIGS AND AREAS OF PATCHY FOG...THUS
HAVE OPTED TO INTRODUCE MVFR AT THE INLAND SITES AS OF NOW.
NORTHEAST WINDS AOB 10 KTS WILL CONTINUE WITH ISOLATED SHOWERS
POSSIBLE.
EXTENDED OUTLOOK...SHOWERS AND ISOLATED T-STORMS EXPECTED THURSDAY
THROUGH SUNDAY. HEAVY RAINFALL AT TIMES COULD PRODUCE LOCALIZED
PERIODS OF MVFR/IFR/LIFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1050 AM WEDNESDAY...THE COLD FRONT IS PUSHING THROUGH THE
COASTAL WATERS THIS MORNING AND WILL STALL TO THE SOUTH AND EAST
OF OUR WATERS THE SMALL CRAFT EXERCISE CAUTION CONTINUES AS SEAS
CONTINUE AT ROUGH 3 TO 5 FEET ESPECIALLY 10 MILES AND FARTHER OFF
THE COAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...COLD FRONT SOUTH OF THE WATERS LEAVES
GUSTY NE WINDS IN ITS WAKE...WITH SPEEDS OF 15-20 KTS
THURSDAY...FALLING TO 10-15 KTS FRIDAY...AND THEN EVEN LIGHTER
LATE FRIDAY AS THE FRONT SLOWLY LIFTS BACK NORTH ACROSS THE
WATERS. WAVE HEIGHTS WILL BE PRIMARILY FORMED BY A E/NE WIND
CHOP...THUS THE HIGHEST SEAS WILL BE ON THURSDAY WITH SIGNIFICANT
HEIGHTS OF 3-5 FT...FALLING TO 2-3 FT ON FRIDAY. A SMALL CRAFT
EXERCISE CAUTION HAS BEEN ISSUED FOR ALL THE WATERS THROUGH
THURSDAY DUE TO THE STRONG WINDS AND HIGH SEAS...BUT WILL EXPIRE
DURING THURSDAY NIGHT AS CONDITIONS IMPROVE.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...STALLED BOUNDARY OVER THE WATERS WILL PUSH
NORTHWARD ON SATURDAY...EVENTUALLY CLEARLY THE WATERS AND LEAVING
INCREASING SOUTHERLY WINDS ON SUNDAY. WHILE WINDS INITIALLY WILL
QUITE LIGHT...5-10 KTS OF VARIABLE DIRECTION...THEY WILL SLOWLY
BECOME S/SE LATE SATURDAY AND SUNDAY...AT AROUND 10 KTS. SEAS WILL
BE 2-3 FT THROUGH THE PERIOD...WITH A SOUTHERLY WIND WAVE BECOMING
DOMINANT SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DRH
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...SGL
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
945 AM EDT WED AUG 14 2013
.DISCUSSION...
A COLD FRONT TO OUR SOUTH AND STRONG HIGH PRESSURE OVER THE GREAT
LAKES REGION WILL PROVIDE A VERY PLEASANT DAY FOR MID-AUGUST
ACROSS THE AREA. AFTERNOON DEWPOINTS WILL FALL INTO THE 50S WITH
DAYTIME MIXING...WITH HIGH TEMPS IN THE UPPER 70S TO LOWER 80S IN
MOST SPOTS. THE CURRENT FORECAST HAS A SLIGHT CHANCE POP IN SW NC.
WHILE THE NAM DOES SHOW SOME DEVELOPMENT IN THE NC MTNS AND UPSTATE
SC THIS AFTERNOON IN A LOW LEVEL CONVERGENCE ZONE...THE RUC SOUNDING
AT RHP LOOKS VERY STABLE. EXPECT THAT ANY SHOWERS THAT DEVELOP WILL
STAY TO OUR SOUTH AND EAST. WILL UPDATE TO REMOVE POPS IN THIS
AREA...OTHERWISE NO CHANGES ARE NEEDED.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
941 AM CDT WED AUG 14 2013
.UPDATE...
THE CONVECTIVE COMPLEX OVER WESTERN COUNTIES CONTINUES TO WEAKEN
WHILE BRINGING STEADY BENEFICIAL RAINS TO AREAS GENERALLY WEST OF
I-35 WEST. A FEW OF THESE SHOWERS HAVE MADE IT AS FAR EAST AS
TARRANT COUNTY LATE THIS MORNING. EAST AND SOUTH OF THE WEAKENING
STORM COMPLEX...TEMPERATURES SHOULD BE ABLE TO CLIMB INTO THE
UPPER 80S...ALLOWING FOR SCATTERED STORMS TO DEVELOP BY THIS
AFTERNOON. COVERAGE SHOULD BE HIGHEST OVER THE SOUTHERN-MOST
COUNTIES WHERE THE BEST MOISTURE AND INSTABILITY RESIDE...WITH
SLIGHTLY LESS OR WIDELY SCATTERED COVERAGE EXPECTED IN DALLAS-
FORT WORTH AND SURROUNDING AREAS. WILL CONTINUE WITH THE HIGHEST
POPS IN THE SOUTH THIS AFTERNOON DECREASING WITH LATITUDE TO NEAR
20 PERCENT ALONG THE RED RIVER. THE SEVERE THREAT WILL BE MARGINAL
AND THE BEST CHANCES FOR SEVERE STORMS CONTAINING DAMAGING WINDS
WILL LIKELY BE SOUTH OF THE INTERSTATE 20 CORRIDOR WHERE MLCAPE
WILL EXCEED 1000J/KG AND SURFACE TEMPS WILL BE WARMEST. THE
FORECAST LOOKS ON TRACK AT THIS TIME...THOUGH ADJUSTMENTS COULD BE
MADE LATER DEPENDING ON FUTURE RADAR TRENDS AND UPDATED MODEL
DATA.
30
&&
.AVIATION...
FOR THE 12Z TAFS...THE PRIMARY AVIATION WEATHER CONCERN IS
THUNDERSTORM CHANCES THROUGH TONIGHT.
SHORT TERM FORECAST...A LINE OF SHOWERS AND THUNDERSTORMS WAS
DRAPED JUST SOUTH OF MOST METROPLEX AREA TAF SITES...HOLDING NORTH
OF WACO AT THE TIME OF THIS DISCUSSION. AFW/DFW/DAL WERE ALL AT
LEAST 10 NM REMOVED FROM THIS LINE OF CONVECTION BY 1130Z...SO
WENT AHEAD WITH JUST A VCSH MENTION THROUGH 13Z FOR THESE SITES.
FTW/GKY WERE WITHIN 10 MILES OF ONGOING CONVECTION...SO CONTINUED
TO CARRY VCTS FOR THESE SITES THROUGH 13 OR 14Z.
FOR KACT...AS OF 1130Z ALL ONGOING CONVECTION WAS WELL NORTH OF
WACO...BUT REGIONAL RADARS SHOWED AN OUTFLOW BOUNDARY MOVING
RAPIDLY TO THE SOUTH JUST EAST OF I-35. WENT AHEAD AND CARRIED A
VCSH FOR KACT THIS MORNING DUE TO UNCERTAINTY ON NEW PRECIPITATION
DEVELOPING ALONG THIS SOUTHWARD MOVING OUTFLOW.
THROUGH THIS AFTERNOON... PERSISTENT CONVECTION ACROSS WEST TEXAS
OVERNIGHT AND EARLY THIS MORNING HAS ACTUALLY CAUSED AN UPPER
LEVEL DISTURBANCE TO DEVELOP. THIS DISTURBANCE IS EXPECTED TO MOVE
SLOWLY SOUTHEAST TOWARDS NORTH TX FOR THIS AFTERNOON. WHETHER THIS
WILL CAUSE SHOWERS AND THUNDERSTORMS TO DEVELOP AROUND THE DFW
AREA THIS AFTERNOON IS THE MAJOR FORECAST CONCERN FOR TODAY.
THUNDERSTORM CHANCES SEEM DEPENDENT UPON THE DFW AREA GETTING SOME
BREAKS IN THE CLOUD COVER BEFORE THE UPPER DISTURBANCE ARRIVES
BY/AROUND 21Z. WITHOUT MUCH CONFIDENCE IN CLOUDS CLEARING UP BY
THAT TIME ONLY CARRIED VCSH FOR ALL METROPLEX AREA TAFS THROUGH
01Z. WILL HAVE TO MONITOR CLOUD COVER AND THE UPSTREAM DISTURBANCE
THROUGH THE MORNING HRS AND ADJUST THE TAFS ACCORDINGLY.
FOR KACT...MORE OR LESS FOLLOWED OUTPUT FROM THE HRRR WHICH BREAKS
OUT SCATTERED THUNDERSTORM ACTIVITY ALL AROUND WACO AFTER 18Z NEAR
A STALLED OUT FRONTAL BOUNDARY IN THE AREA. WITH THE FRONT ALREADY
IN PLACE...CONFIDENCE WAS HIGH ENOUGH TO BELIEVE THE HRRR OUTPUT
AND PLACE 3 HRS OF -TSRA IN THE TAF FROM 18Z TO 21Z. AFTER 21Z
CARRIED VCSH WITHOUT MUCH CONFIDENCE ON WHAT THE INFLUENCE OF THE
UPPER LEVEL DISTURBANCE WILL BE ON THE WACO AREA.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 416 AM CDT WED AUG 14 2013/
SURFACE ANALYSIS EARLY THIS MORNING SHOWED TWO SURFACE BOUNDARIES
THAT WILL HAVE AN EFFECT ON PRECIPITATION COVERAGE AND TEMPS
ACROSS NORTH TEXAS TODAY AND TONIGHT. CONSOLIDATED OUTFLOW
BOUNDARY AND EFFECTIVE COLD FRONT WAS ACROSS THE SOUTHERN PART OF
THE CWA AND WAS STATIONARY ALONG A LINE FROM NEAR LAMPASAS TO
CENTERVILLE. THE SECOND BOUNDARY WAS LOCATED ALONG THE LEADING
EDGE OF SOME LOWER THETA-E AIR AND MAY BE CORRELATED WITH A FRONTAL
BOUNDARY AT 850 MB. THIS BOUNDARY WAS ANALYZED FROM NEAR BOWIE TO
SOUTH OF PARIS AND WAS MOVING SOUTH.
WILL CONTINUE WITH CHANCE POPS ACROSS NORTH AND CENTRAL TEXAS
TODAY...WITH HIGHEST POPS AND GREATEST COVERAGE OF STORMS FORECAST
IN SOUTHERN AREAS THIS AFTERNOON. THE CLUSTER OF ELEVATED STORMS
THIS MORNING ACROSS TARRANT AND PARKER COUNTIES MAY CONTINUE TO
EXPAND AS IT DEVELOPS TO THE EAST AND SOUTHEAST.
BY THIS AFTERNOON...EXPECT THE MORNING ACTIVITY TO DISSIPATE AS
THE NORTHERN SURFACE BOUNDARY MOVES SOUTH. BY MID AFTERNOON...THIS
BOUNDARY WILL MOVE TO NEAR A TYLER TO WACO LINE AND BE A FOCUS FOR
SCATTERED STRONG /ISOLATED SEVERE/ THUNDERSTORMS. DESPITE WEAK
DEEP LAYER SHEAR...EXPECT POCKETS OF INSTABILITY UP TO 2000 J/KG
TO SUPPORT STRONG STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND
WIND GUSTS. THE AFTERNOON ACTIVITY WILL PERSIST INTO THE EVENING
HOURS...BUT WILL TEND TO DIMINISH QUICKLY AFTER MIDNIGHT AS IT
SHIFTS TO THE SOUTH AND SOUTHEAST WITH THE SURFACE BOUNDARY.
RAIN CHANCES WILL BE CONFINED TO WESTERN AND SOUTHERN ZONES ON
THURSDAY AS DRIER AND MORE STABLE AIR WORKS INTO THE AREA FROM THE
EAST AND NORTHEAST. THURSDAY NIGHT SHOULD BE DRY...BUT A RATHER
STRONG SHORTWAVE TROUGH IS FORECAST TO DIG SOUTHEAST INTO OKLAHOMA
BY FRIDAY MORNING. EVEN THOUGH DEEP-LAYER MOISTURE WILL NOT BE AS
FAVORABLE AS TODAY FOR CONVECTION...THE FORCING FOR LARGE SCALE
ASCENT ACROSS NORTH TEXAS LOOKS STRONG BY AUGUST STANDARDS. HAVE
THEREFORE INTRODUCED CHANCE POPS FOR MOST OF THE AREA DURING THE
DAY FRIDAY.
DRY WEATHER FORECAST FROM FRIDAY NIGHT...THROUGH THE WEEKEND...AND
INTO EARLY NEXT WEEK AS THE ROCKIES UPPER HIGH EXPANDS AND THE
UPPER FLOW FLATTENS ACROSS THE CONUS. HIGH TEMPERATURES WILL
RETURN TO NEAR SEASONAL NORMALS IN THE MID-UPPER 90S BY SATURDAY...
BUT NO 100 DEGREE HEAT IS IN THE FORECAST THROUGH DAY 7 /TUES AUG
20/.
...09...
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 92 72 92 70 91 / 30 20 10 10 20
WACO, TX 96 74 92 68 94 / 50 40 30 10 20
PARIS, TX 87 63 86 63 87 / 20 10 5 10 30
DENTON, TX 91 70 90 67 89 / 30 10 10 10 30
MCKINNEY, TX 91 67 90 64 90 / 30 10 10 10 30
DALLAS, TX 93 73 92 70 91 / 30 20 10 10 30
TERRELL, TX 91 69 91 65 91 / 30 20 10 10 30
CORSICANA, TX 95 72 92 67 93 / 60 30 10 10 30
TEMPLE, TX 97 73 93 69 94 / 50 40 30 10 20
MINERAL WELLS, TX 91 71 92 68 91 / 40 30 30 10 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
92/30
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
656 AM CDT WED AUG 14 2013
.AVIATION...
FOR THE 12Z TAFS...THE PRIMARY AVIATION WEATHER CONCERN IS
THUNDERSTORM CHANCES THROUGH TONIGHT.
SHORT TERM FORECAST...A LINE OF SHOWERS AND THUNDERSTORMS WAS
DRAPED JUST SOUTH OF MOST METROPLEX AREA TAF SITES...HOLDING NORTH
OF WACO AT THE TIME OF THIS DISCUSSION. AFW/DFW/DAL WERE ALL AT
LEAST 10 NM REMOVED FROM THIS LINE OF CONVECTION BY 1130Z...SO
WENT AHEAD WITH JUST A VCSH MENTION THROUGH 13Z FOR THESE SITES.
FTW/GKY WERE WITHIN 10 MILES OF ONGOING CONVECTION...SO CONTINUED
TO CARRY VCTS FOR THESE SITES THROUGH 13 OR 14Z.
FOR KACT...AS OF 1130Z ALL ONGOING CONVECTION WAS WELL NORTH OF
WACO...BUT REGIONAL RADARS SHOWED AN OUTFLOW BOUNDARY MOVING
RAPIDLY TO THE SOUTH JUST EAST OF I-35. WENT AHEAD AND CARRIED A
VCSH FOR KACT THIS MORNING DUE TO UNCERTAINTY ON NEW PRECIPITATION
DEVELOPING ALONG THIS SOUTHWARD MOVING OUTFLOW.
THROUGH THIS AFTERNOON... PERSISTENT CONVECTION ACROSS WEST TEXAS
OVERNIGHT AND EARLY THIS MORNING HAS ACTUALLY CAUSED AN UPPER
LEVEL DISTURBANCE TO DEVELOP. THIS DISTURBANCE IS EXPECTED TO MOVE
SLOWLY SOUTHEAST TOWARDS NORTH TX FOR THIS AFTERNOON. WHETHER THIS
WILL CAUSE SHOWERS AND THUNDERSTORMS TO DEVELOP AROUND THE DFW
AREA THIS AFTERNOON IS THE MAJOR FORECAST CONCERN FOR TODAY.
THUNDERSTORM CHANCES SEEM DEPENDENT UPON THE DFW AREA GETTING SOME
BREAKS IN THE CLOUD COVER BEFORE THE UPPER DISTURBANCE ARRIVES
BY/AROUND 21Z. WITHOUT MUCH CONFIDENCE IN CLOUDS CLEARING UP BY
THAT TIME ONLY CARRIED VCSH FOR ALL METROPLEX AREA TAFS THROUGH
01Z. WILL HAVE TO MONITOR CLOUD COVER AND THE UPSTREAM DISTURBANCE
THROUGH THE MORNING HRS AND ADJUST THE TAFS ACCORDINGLY.
FOR KACT...MORE OR LESS FOLLOWED OUTPUT FROM THE HRRR WHICH BREAKS
OUT SCATTERED THUNDERSTORM ACTIVITY ALL AROUND WACO AFTER 18Z NEAR
A STALLED OUT FRONTAL BOUNDARY IN THE AREA. WITH THE FRONT ALREADY
IN PLACE...CONFIDENCE WAS HIGH ENOUGH TO BELIEVE THE HRRR OUTPUT
AND PLACE 3 HRS OF -TSRA IN THE TAF FROM 18Z TO 21Z. AFTER 21Z
CARRIED VCSH WITHOUT MUCH CONFIDENCE ON WHAT THE INFLUENCE OF THE
UPPER LEVEL DISTURBANCE WILL BE ON THE WACO AREA.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 416 AM CDT WED AUG 14 2013/
SURFACE ANALYSIS EARLY THIS MORNING SHOWED TWO SURFACE BOUNDARIES
THAT WILL HAVE AN EFFECT ON PRECIPITATION COVERAGE AND TEMPS
ACROSS NORTH TEXAS TODAY AND TONIGHT. CONSOLIDATED OUTFLOW
BOUNDARY AND EFFECTIVE COLD FRONT WAS ACROSS THE SOUTHERN PART OF
THE CWA AND WAS STATIONARY ALONG A LINE FROM NEAR LAMPASAS TO
CENTERVILLE. THE SECOND BOUNDARY WAS LOCATED ALONG THE LEADING
EDGE OF SOME LOWER THETA-E AIR AND MAY BE CORRELATED WITH A FRONTAL
BOUNDARY AT 850 MB. THIS BOUNDARY WAS ANALYZED FROM NEAR BOWIE TO
SOUTH OF PARIS AND WAS MOVING SOUTH.
WILL CONTINUE WITH CHANCE POPS ACROSS NORTH AND CENTRAL TEXAS
TODAY...WITH HIGHEST POPS AND GREATEST COVERAGE OF STORMS FORECAST
IN SOUTHERN AREAS THIS AFTERNOON. THE CLUSTER OF ELEVATED STORMS
THIS MORNING ACROSS TARRANT AND PARKER COUNTIES MAY CONTINUE TO
EXPAND AS IT DEVELOPS TO THE EAST AND SOUTHEAST.
BY THIS AFTERNOON...EXPECT THE MORNING ACTIVITY TO DISSIPATE AS
THE NORTHERN SURFACE BOUNDARY MOVES SOUTH. BY MID AFTERNOON...THIS
BOUNDARY WILL MOVE TO NEAR A TYLER TO WACO LINE AND BE A FOCUS FOR
SCATTERED STRONG /ISOLATED SEVERE/ THUNDERSTORMS. DESPITE WEAK
DEEP LAYER SHEAR...EXPECT POCKETS OF INSTABILITY UP TO 2000 J/KG
TO SUPPORT STRONG STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND
WIND GUSTS. THE AFTERNOON ACTIVITY WILL PERSIST INTO THE EVENING
HOURS...BUT WILL TEND TO DIMINISH QUICKLY AFTER MIDNIGHT AS IT
SHIFTS TO THE SOUTH AND SOUTHEAST WITH THE SURFACE BOUNDARY.
RAIN CHANCES WILL BE CONFINED TO WESTERN AND SOUTHERN ZONES ON
THURSDAY AS DRIER AND MORE STABLE AIR WORKS INTO THE AREA FROM THE
EAST AND NORTHEAST. THURSDAY NIGHT SHOULD BE DRY...BUT A RATHER
STRONG SHORTWAVE TROUGH IS FORECAST TO DIG SOUTHEAST INTO OKLAHOMA
BY FRIDAY MORNING. EVEN THOUGH DEEP-LAYER MOISTURE WILL NOT BE AS
FAVORABLE AS TODAY FOR CONVECTION...THE FORCING FOR LARGE SCALE
ASCENT ACROSS NORTH TEXAS LOOKS STRONG BY AUGUST STANDARDS. HAVE
THEREFORE INTRODUCED CHANCE POPS FOR MOST OF THE AREA DURING THE
DAY FRIDAY.
DRY WEATHER FORECAST FROM FRIDAY NIGHT...THROUGH THE WEEKEND...AND
INTO EARLY NEXT WEEK AS THE ROCKIES UPPER HIGH EXPANDS AND THE
UPPER FLOW FLATTENS ACROSS THE CONUS. HIGH TEMPERATURES WILL
RETURN TO NEAR SEASONAL NORMALS IN THE MID-UPPER 90S BY SATURDAY...
BUT NO 100 DEGREE HEAT IS IN THE FORECAST THROUGH DAY 7 /TUES AUG
20/.
...09...
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 92 72 92 70 91 / 30 20 10 10 20
WACO, TX 96 74 92 68 94 / 50 40 30 10 20
PARIS, TX 87 63 86 63 87 / 20 10 5 10 30
DENTON, TX 91 70 90 67 89 / 30 10 10 10 30
MCKINNEY, TX 91 67 90 64 90 / 30 10 10 10 30
DALLAS, TX 93 73 92 70 91 / 30 20 10 10 30
TERRELL, TX 91 69 91 65 91 / 30 20 10 10 30
CORSICANA, TX 95 72 92 67 93 / 50 30 10 10 30
TEMPLE, TX 97 73 93 69 94 / 50 40 30 10 20
MINERAL WELLS, TX 91 71 92 68 91 / 40 30 30 10 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1145 AM MDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM MDT WED AUG 14 2013
...DRIER AIRMASS MAKING PROGRESS EASTWARD TODAY...POTENTIAL FOR
STRONG STORMS OUT EAST THIS AFTERNOON...
SHORTWAVE MOVING DOWN EASTERN PERIPHERY OF THE UPPER RIDGE IS
KEEPING SCATTERED THUNDERSTORMS GOING ACROSS NORTHEAST/EAST CENTRAL
CO AS LOW LEVEL JET CONTINUES TO INCREASE ACROSS THE FAR EASTERN
PLAINS. KIOWA COUNTY IS MOST LIKELY TO BE CLIPPED BY THESE LATER
THIS MORNING AND FOLLOWED THE HRRR FOR POPS IN THE SHORT TERM AS IT
APPEARS TO BE THE MODEL HANDLING CURRENT CONVECTION BEST.
THUNDERSTORMS SHOULD DIMINISH OUT EAST LATER THIS MORNING.
MEANWHILE...DRIER AIRMASS OUT WEST WILL BE ADVANCING EASTWARD TODAY
WITH SHORT RANGE HIGH RES MODELS SHOWING DEW POINTS ACROSS THE
MOUNTAINS FALLING OFF INTO THE 20S AND 30S IN THE AFTERNOON. LCLS
RISE SUBSTANTIALLY AS A RESULT...AND WITH MORE INVERTED V SOUNDINGS
EXPECT EVAPORATION BELOW CLOUD BASES TO REDUCE PCPN EFFICIENCIES OF
THUNDERSTORMS SOME. HOWEVER...ERRATIC GUSTY WINDS WILL BECOME MORE
OF A THREAT AS A RESULT. MODELS STILL SHOW ENOUGH MOISTURE AND WEAK
FORCING MOVING THROUGH THE RIDGE ASSOC WITH UPPER LEVEL JET FOR
MAINLY ISOLATED AFTERNOON THUNDERSTORMS OUT WEST...WITH SCATTERED
THUNDERSTORMS ACROSS THE SE MTS/PLAINS DURING THE AFTERNOON. BUT
GIVEN THE LOWER THREAT FOR HEAVY RAINFALL...WILL NOT HOIST A FLASH
FLOOD WATCH FOR THE BURN SCARS IN EL PASO/TELLER COUNTIES. OF
COURSE...WALDO CANYON WILL NOT BE ENTIRELY OUT OF THE WOODS AS EVEN
WITH THE DRIER AIRMASS A QUICK .50 TO .75 OF RAIN WITH A STRONGER
STORM IS STILL POSSIBLE. BUT THIS LOOKS LIKE AN OUTLIER POSSIBILITY
FOR TODAY AND MORE LIKELY TO OCCUR FARTHER EAST WHERE GRADIENT OF
HIGHER DEW POINTS WILL BE LURKING. MEANWHILE...SFC DEW POINTS WILL
BE SLOWER TO DECREASE OUT ACROSS THE EASTERN PLAINS...AND NAM12
SHOWS AN AXIS OF 1500+ J/KG OF CAPE OUT OVER THE EASTERN PLAINS
OF KIOWA...BACA...BENT...AND PROWERS COUNTIES DURING THE LATE
AFTERNOON. DEEP LAYER SHEARS WILL BE RUNNING AROUND 35-40
KTS...SUFFICIENT FOR ONE OR TWO STRONG TO SEVERE THUNDERSTORMS.
LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY STORM THREATS AND
SPC HAS AREA OUTLOOKED UNDER A SEE TEXT. THUNDERSTORMS SHOULD
DIMINISH AFTER MIDNIGHT WITH LACK OF FORCING AND AXIS OF LOW LEVEL
JET PULLING AWAY TO THE EAST.
OTHERWISE...TEMPERATURES SHOULD BE A LITTLE WARMER TODAY FOR ALL
AREAS...WITH WITH DRIER SFC DEW POINTS OUT WEST...STARTING TO SEE A
RETURN OF LOWS IN THE 30S FOR SOME OF THE SPOTTY VALLEY LOCATIONS
DUE TO GOOD RADIATIONAL COOLING. LOWS ACROSS THE PLAINS WILL LIKELY
STAY IN THE 50S AND 60S WITH LEE TROFFING AND AXIS OF HIGHER DEW
POINTS HELPING TO KEEP MINS UP. -KT
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 459 AM MDT WED AUG 14 2013
METEOROLOGICAL CHALLENGES DURING THE LONGER TERM INCLUDE WARMER
TEMPERATURES...POTENTIAL STRONG TO SEVERE THUNDERSTORMS OVER FAR
EASTERN SECTIONS THURSDAY AND POPS.
IT STILL APPEARS THAT DRIER AND WARMER CONDITIONS WILL DEVELOP
OVER THE MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO THE
WEEKEND AS UPPER RIDGING BUILDS INTO THE FOUR CORNERS REGION BY THIS
WEEKEND. ALSO...LATEST PRECIPITABLE WATER VALUE PROJECTIONS DROP
TO BETWEEN 0.50 AND 0.70 INCHES OVER THE INTERSTATE 25 CORRIDOR
DURING THIS TIME-FRAME.
STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO DEVELOP OVER
PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS THURSDAY AS
PROJECTED LOCALIZED CAPES AND LIS NEARING 2000 J/KG AND -7C
RESPECTIVELY INTERACT WITH 0 TO 6 KM BULK SHEARS AROUND 40 KNOTS.
WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
ARE STILL ANTICIPATED OVER THE MAJORITY OF THE CWFA FROM THURSDAY
INTO EARLY SUNDAY. EVEN THOUGH RATHER UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM DIRECTLY
IMPACTS A BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY SHOULD THEN BE
NOTED...INITIALLY OVER WESTERN SECTIONS LATER SUNDAY AND THEN
CONTINUE INTO NEXT TUESDAY AS A NORTHERLY SURFACE ATTEMPTS TO
MOVE ACROSS EASTERN SECTIONS MONDAY AND ATMOSPHERIC MOISTURE
VALUES INCREASE. FORECAST MODEL SOUNDINGS PROJECT THAT
PRECIPITABLE WATER VALUES OVER THE INTERSTATE 25 CORRIDOR
INCREASE TO AROUND ONE INCH AT TIMES BY EARLY NEXT WEEK.
AT THIS TIME...IT STILL APPEARS THAT THE HIGHEST POTENTIAL FOR
LOCALIZED HEAVY RAIN AND ASSOCIATED FLASH FLOODING
CONCERNS(ESPECIALLY OVER THE AREA BURN SCARS) WILL BE POSSIBLE BY
NEXT MONDAY AND TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR
CLOSELY.
ABOVE SEASONAL AVERAGE MID-AUGUST MAXIMUM TEMPERATURES SHOULD BE
EXPERIENCED OVER THE MAJORITY OF THE FORECAST DISTRICT FROM
THURSDAY INTO NEXT TUESDAY WITH THE WARMEST CONDITIONS ANTICIPATED
THIS WEEKEND AS 700 MB TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB
TO AROUND 18C.
MAXIMUM TEMPERATURES THIS WEEKEND OVER MANY SECTIONS OF THE
SOUTHEASTERN COLORADO PLAINS SHOULD REACH WELL INTO THE 90S THIS
WEEKEND. FINALLY...AS HAS BEEN THE CASE DURING THE PAST SEVERAL
DAYS...GENERALLY LIGHT GRADIENT WINDS SHOULD CONTINUE FROM
THURSDAY INTO NEXT TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1139 AM MDT WED AUG 14 2013
IFR STRATUS HAS BEEN QUICKLY DISSIPATING OVER THE PLAINS AND WON`T
INCLUDE ANY IN THE KPUB OR KCOS 18Z TAFS. MAINLY VFR CONDITIONS
EXPECTED TODAY AND TONIGHT WITH ISOLATED TO SCATTERED THUNDERSTORMS
DEVELOPING OVER THE MOUNTAINS THIS AFTERNOON THEN DRIFTING
EASTWARD ACROSS THE PLAINS DURING THE LATE AFTERNOON AND EVENING.
BRIEF MVFR CIGS/VIS WILL BE POSSIBLE WITH THUNDERSTORMS...ESPECIALLY
OVER THE PLAIN NEAR THE KS BORDER. WILL CONTINUE TO INCLUDE A VCTS
AT ALL TAF SITES LATE THIS AFTERNOON AND EARLY THIS
EVENING...ALTHOUGH TSRA SHOULD BE WEAKER AND MORE ISOLATED THAN
THE PAST FEW DAYS. MAIN IMPACT OF STORMS WILL BE GUSTY AND ERRATIC
OUTFLOW WINDS TO 40 KNOTS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS GAYLORD MI
143 PM EDT WED AUG 14 2013
.SYNOPSIS...
ISSUED AT 327 AM EDT WED AUG 14 2013
HIGH PRESSURE IN SOUTH CENTRAL CANADA WILL MOVE TOWARD THE SOUTHERN
GREAT LAKES TONIGHT...THEN STALL OUT JUST TO OUR SOUTH AND EAST.
THIS WILL PROVIDE FOR AN EXTENDED PERIOD OF QUIET WEATHER...ALONG
WITH A GRADUAL WARMING TREND.
&&
.UPDATE...
ISSUED AT 127 PM EDT WED AUG 14 2013
IF THE 12Z GFS, NAM, AND RUC13 ARE RIGHT, THE 850 MB TEMPERATURES
ARE WARMING TO 6C BY NOW. THE 00Z ECMWF SAYS THAT AT THIS POINT
THE AREA OF 4C AIR OVER N LAKE MICHIGAN WOULD BE SMALLER. BASED ON
THE CURRENT VIS IMAGE, THINK THAT THE ECMWF HAS A BETTER HANDLE ON
IT. ALL OF THE MODELS HAVE A SIMILAR MOISTURE LOOK IN THE 850-700
MB LAYER AS THE CLOUDS STREAM OFF LAKES MICHIGAN AND SUPERIOR AND
TAKE A BIT OF TIME (ROUGHLY THE FIRST 10MILES OR SO) BEFORE THEY
GROW AND EXPAND. THIS TREND WILL CONTINUE FOR A FEW MORE HOURS AS
THE WARMER AIR BEGINS TO TAKE OVER. TEMPERATURES SEEM TO BE ON
TRACK WITH THE SFC WINDS 5 TO 10 KNOTS GUSTS TO 15KNOTS. SO WILL
LEAVE THE FORECAST AS IS.
UPDATE ISSUED AT 1053 AM EDT WED AUG 14 2013
850 MB TEMPERATURES ARE STILL AROUND +4C ON THE SOUNDING THIS
MORNING. SO WE WILL CONTINUE, AT LEAST THIS MORNING AND EARLY
AFTERNOON, WITH THE LAKE CU/SC CLOUDS. HOWEVER, THE LATEST NAM AND
RUC RUNS INSIST THAT BY 18Z THE 850 MB TEMPERATURES WILL BE AROUND
+6C OR +7C. THIS WOULD CERTAINLY CUT DOWN THE AMOUNT OF CLOUDS FOR
THE AFTERNOON AS THE DELTA T DIMINISHES. WILL KEEP THE GOING
FORECAST WITH PARTLY SUNNY AND HIGHS IN THE 60S.
UPDATE ISSUED AT 631 AM EDT WED AUG 14 2013
NO SIGNIFICANT UPDATES...BUT DID DECREASE CLOUD COVER TO CLEAR
ACROSS EASTERN UPPER...AND ONLY SOME PATCHY LAKE CLOUDS ACROSS NW
LOWER. ALSO SOME SHALLOW FOG IN LOW LYING AREAS. THIS WILL BURN
OFF QUICKLY...AND MOSTLY SUNNY SKIES WILL TURN TO DEVELOPING
STRATO CUMULUS...SIMILAR TO YESTERDAY...BUT NOT EXPECTED TO BE AS
WIDESPREAD.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 327 AM EDT WED AUG 14 2013
ITS JUST GOTTA GET BETTER RIGHT? AND INDEED...IT WILL. CULPRIT
BEHIND YESTERDAYS RIDICULOUSLY UNSEASONABLY COLD WEATHER STILL
PLAGUING THE REGION...WITH ANOMALOUSLY DEEP TROUGHING CENTERED OVER
THE EASTERN LAKES. COLD AIRMASS CENTERED RIGHT OVER THE HEART OF THE
NORTHERN LAKES...AS NOTED BY LOCAL 00Z SOUNDING WHICH HAD H8
TEMPERATURES OF ONLY 2C. WINDS AND POCKETS OF CLOUD COVER PREVENTING
SURFACE TEMPERATURES FROM DROPPING AS MUCH AS THEY COULD HAVE.
STILL...SIMPLY NOT YOUR TYPICAL MID AUGUST NIGHT WITH CURRENT
READINGS MOSTLY IN THE 40S. NOT ALL IS DOOM AND GLOOM... HOWEVER...
WITH MID LEVEL HEIGHTS ALREADY ON THE INCREASE AND SURFACE HIGH
PRESSURE BUILDING INTO THE REGION. THIS SIGNALS BETTER DAYS
AHEAD...KICKED OFF BY TODAY`S SLOW MODERATION AND INCREASING AMOUNTS
OF SUNSHINE (FANS OF SUMMER REALLY GOING TO LIKE THE EXTENDED
FORECAST...READ ABOUT THOSE GLORIOUS DETAILS IN THE LONG TERM
PORTION OF THE FORECAST). SIMPLY NOT MANY FORECAST CONCERNS HEADING
THROUGH TONIGHT...AND WHAT THERE ARE CENTER MAINLY ON CLOUD AND
TEMPERATURE TRENDS.
WHILE BY NO MEANS WARM...TODAY WILL FEEL A HECK OF A LOT BETTER THAN
TUESDAY. HIGH PRESSURE WILL CONTINUE TO BUILD INTO OUR AREA AS DEEP
UPPER TROUGHING SLIDES FURTHER OFF TO THE EAST. WEAK SHORTWAVE DOES
SLIDE SOUTHEAST ON BACKSIDE OF DEPARTING PARENT TROUGH...BUT IS
EXPECTED TO COME THROUGH WITH LITTLE FANFARE GIVEN DEARTH OF DEEP
MOISTURE. THERMAL PROFILES BEGIN TO MODERATE...AND INFLUX OF DRY AIR
SHOULD LEAD TO AT LEAST PARTIAL SUNSHINE. COOL AIR ALOFT LIKELY TO
LEAD TO ANOTHER ROUND OF DIURNALLY DRIVEN CLOUD COVER...ESPECIALLY
IN THE FAVORED AREAS OF NORTHEAST LOWER AND EASTERN UPPER MICHIGAN.
STRONG H7 CENTERED CAPPING AND DRY LOW LEVELS SHOULD PREVENT ANY
SHOWER ACTIVITY. CAN FIND NO COMPELLING REASON TO DEVIATE FROM
INHERITED CLOUD COVER FORECAST...FEATURING A MAINLY PARTLY CLOUDY
DAY...WITH MORE SUNSHINE CLOSER TO LAKE MICHIGAN. SIMPLE AIRMASS
MODIFICATION AND SUNSHINE WILL ALLOW TEMPERATURES TO MODERATE
SEVERAL DEGREES...WITH DAYTIME HIGHS MAKING A RUN INTO THE MIDDLE
AND UPPER 60S. STILL SEVERAL DEGREES BELOW NORMAL...BUT A DEFINITE
STEP IN THE RIGHT DIRECTION.
MAINLY CLEAR AND QUIET HEADING THROUGH TONIGHT AS HIGH PRESSURE
SETTLES ACROSS THE NORTHERN OHIO VALLEY. PLACEMENT OF CENTER OF HIGH
TO OUR SOUTH SHOULD KEEP TEMPERATURES FROM BECOMING TOO EXTREME.
STILL...ANOTHER CHILLY NIGHT...WITH INTERIOR LOWS MAINLY IN THE
40S...AND SHORELINE COMMUNITIES JUST A TOUCH WARMER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 327 AM EDT WED AUG 14 2013
READY FOR A RETURN TO SUMMER? UPPER LEVEL PATTERN WILL MORPH FROM
EASTERN CONUS TROUGHING AND COOL WEATHER...TO RISING HEIGHTS IN A
ZONAL MORE SEASONABLE PATTERN. DOME OF WARM/HOT AIR AND PERSISTENT
RIDGING OVER THE ROCKIES WILL SLOWLY PEEL OVER INTO THE GREAT
LAKES...HELPING RETURN US TO MORE NORMAL SUMMERTIME WARMTH.
WEDNESDAY THROUGH FRIDAY...THE GREATEST HEIGHT RISES WILL OCCUR
OVER THIS TIME PERIOD...WHILE THE LOW LEVEL COOLER POOL OF AIR
REMAINS ENTRENCHED BACK ACROSS THE GREAT LAKES. EITHER WAY...THE
AIR MASS WILL BE RELATIVELY DRY...WITH WEAK SHORTWAVE ENERGY
DROPPING IN FROM SRN CANADA OUT OF WEAKENING NW FLOW ALOFT. MODELS
STILL ANTICIPATING A WEAK PIECE OF THIS ENERGY POSSIBLY CUTTING OFF
IN THE HEART OF THE COUNTRY AND LIFTING THROUGH THE SRN/EASTERN
GREAT LAKES. SUCH WEAK FLOW/ENERGY AND RELATIVELY DRY AIR FOR ANY
MENTION OF A CHANCE OF PRECIPITATION. WINDS WILL BE LIGHT WITH
AFTERNOON LAKE BREEZES CONSOLIDATING THE BETTER SCATTERED
AFTERNOON CUMULUS TO NE LOWER AND EASTERN UPPER AWAY FROM THE
LAKES. TEMPERATURES WILL WARM FROM THE MIDDLE 70S THURSDAY TO
AROUND 80F BY SATURDAY. BEAUTIFUL WEATHER.
SATURDAY THROUGH TUESDAY...HEIGHTS WILL HAVE RISEN AS MUCH AS THEY
ARE EXPECTED. WITH A WESTERLY LOW LEVEL FLOW ALREADY HAVE USHERED
IN MORE SEASONABLY WARM SUMMERTIME AIR. TEMPERATURES OVER THIS
TIME PERIOD WILL HAVE WARMED TO THE LOWER HALF OF THE 80S FOR MOST
LOCALES. CHANCES FOR SHOWERS AND A STORM ARE STILL QUITE
SMALL...BUT BETTER SHORTWAVE ENERGY AND EXPECTED TO DROP INTO THE
REGION MONDAY THROUGH TUESDAY. CONTINUED BEAUTIFUL WEATHER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 127 PM EDT WED AUG 14 2013
TVC, PLN, AND MBL SHOULD BE PREDOMINATELY SCT TO BKN VFR CIGS, AS
THEY ARE IN THAT TRANSITION ZONE WHERE THE CLOUDS ARE JUST GETTING
GOING. AS WE GET FURTHER INTO THE DAY, AS THE TEMPERATURES AT 850
MB WARM AND THE MOISTURE DIMINISHES, WILL EXPECT THAT THESE THREE
SITES WILL HAVE DIMINISHING CLOUDS. APN, WILL TAKE A LITTLE
LONGER, BUT ITS CIGS HAVE ALL BEEN IN THE VFR CATEGORY, AND
CURRENTLY THIS LOOKS LIKE IT WILL REMAIN THAT WAY INTO THE
EVENING, WHEN THE CLOUDS EVAPORATE THERE. WINDS WILL BECOME
VARIABLE OVERNIGHT AS THE HIGH ALLOWS THE SFC WINDS TO DECOUPLE.
THURSDAY LOOKS LIKE IT WILL BE A LESS CLOUDIER VERSION OF TODAY AS
THE WINDS REMAIN, BUT THE TEMPERATURES WILL BE WARMER SO THAT WE
DON`T GET DIURNAL/LAKE CLOUDS.
&&
.MARINE...
ISSUED AT 327 AM EDT WED AUG 14 2013
PRESSURE GRADIENT WILL GRADUALLY RELAX HEADING THROUGH
TODAY AND TONIGHT AS HIGH PRESSURE BUILDS SOUTHEAST TOWARDS THE
NORTHERN OHIO VALLEY. CURRENT NORTH TO NORTHWEST WINDS WILL
GRADUALLY BACK MORE WESTERLY TODAY...AND BECOME SOUTHWEST THROUGH
THE OVERNIGHT HOURS. WINDS WILL REMAIN A TOUCH GUSTY...ESPECIALLY UP
NEAR THE STRAITS AND ACROSS WHITEFISH BAY. WIND SPEEDS AND WAVES
SHOULD REMAIN BELOW SCA CRITERIA. ALL INHERITED ADVISORIES WILL BE
DROPPED WITH THIS FORECAST RELEASE.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JL
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...JL
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
125 PM EDT WED AUG 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT WED AUG 14 2013
DRY HIGH PRESSURE WILL CONTINUE TO BE THE MAIN STORY TODAY. NW WINDS
WILL BE THE RULE...KEEPING LOCATIONS NEAR LAKE SUPERIOR IN THE 60S
FOR HIGH TEMPS WHILE REACHING INTO THE LOWER 70S INLAND.
A THIN RIBBON OF CLOUDS ACROSS S ONTARIO AND N LAKE SUPERIOR WILL
CONTINUE TO SHIFT SSE AND EXPAND OVER LAKE SUPERIOR THIS
MORNING...AND PUSH OVER CENTRAL AND E UPPER MI THROUGH THE DAY
TODAY. THIS BAND HAS BEEN PICKED UP BY ONLY A FEW MODELS...NAMELY
THE RUC AND CANADIAN...AND TO A LESSER EXTENT THE NAM. WILL LEVERAGE
THEM MORE ON THE CLOUD FCST THROUGH THE DAY TODAY GIVEN THEIR BETTER
INITIAL PROGNOSIS.
ANOTHER MOSTLY CLEAR NIGHT IS IN STORE FOR US. HOWEVER...TEMPS
SHOULD BOTTOM OUT AROUND 5F WARMER THAN THIS MORNING. WILL KEEP ANY
MENTION OF FROST OUT OF THE FCST WITH THE LOWEST READINGS EXPECTED
AT THIS TIME BEING RIGHT AROUND 40F INLAND FROM THE GREAT LAKES.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 451 AM EDT WED AUG 14 2013
THU AND THU NIGHT...NW MID/UPPER LEVEL FLOW THROUGH THE NRN GREAT LAKES
WILL PREVAIL BETWEEN A TROUGH OVER QUEBEC AND A RIDGE FROM THE SW
CONUS INTO CNTRL CANADA. WITH THE DRY AIRMASS REMAINING OVER THE
REGION...ANY WEAK SHORTWAVES WILL NOT PRODUCE ANY PCPN. INCEASING
WAA AS THE SFC HIGH SHIFTS TOWARD THE SRN GREAT LAKES WILL PUSH 850
MB TEMPS INTO THE 10C-12C ALLOWING HIGHS TO CLIMB BACK INTO THE MID
AND UPPER 70S. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
DROP BACK TO AROUND 50.
FRI...ALTHOUGH LOW LEVEL MOISTURE TRANSPORT BACK INTO THE REGION
WILL BE MODEST...EXPECT ENOUGH OF AN INCREASE FOR DEWPOINTS TO CLIMB
INTO THE LOWER TO MID 50S. THE NAM/GFS/UKMET SUGGEST THAT SOME PCPN
MAY BE POSSIBLE...ESPECIALY DURING PEAK HEATING WITH MLCAPE VALUES
CLIMBING INTO THE 400-800 J/KG RANGE. HOWEVER...THE MODELS MAY ALSO
BE TOO AGGRESSIVE WITH THE AMOUNT OF MOISTURE AVAILABLE MAKING THE
INVERSION/CAPPING AROUND 700 MB MORE DIFFICULT TO OVERCOME.
SO...ONLY ADDED SLIGHT CHANCE WORDING FOR SHRA/TSRA FOR INLAND WEST
LOCATIONS WITH POPS REMAINING AOB 20 PCT.
SAT...THE MID LEVEL RIDGE WILL BUILD INTO THE AREA...BOOSTING THE
CAPPING AND REDUCING ANY PCPN CHANCES EVEN THOUGH LOW LEVEL MOISTURE
WILL ALSO INCREASE. TEMPERATURES WILL REMAIN ABOVE AVERAGE WITH
HIGHS INTH THE UPPER 70S.
SUN-TUE...THE GFS/GEM/UKMET SUGGEST THAT A SHORTWAVE TROUGH MAY MOVE
INTO THE NRN GREAT LAKES MON INTO MON NIGHT BRINGING SHRA/TSRA POTENTIAL
WHILE THE ECMWF WIH A MORE ZONAL PATTERN KEEPS A WEAKER SHRTWV
FARTHERN N THROUGH NRN ONTARIO. GIVEN MODEL DIFFERENCES...FCST
REMAINS IN LIE WITH MDLS CONSENSUS SLIGHT CHANCE POPS. TEMPERATURES
WILL REMAIN ABOVE NORMAL WITH HIGHS FROM THE UPPER 70S TO THE LOWER
80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 125 PM EDT WED AUG 14 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD...AS A HIGH PRESSURE
RIDGE REMAINS OVER THE AREA. EXPECT THE DIURNAL CU TO DIMINISH
TOWARDS EVENING AND A MAINLY CLEAR SKY OVERNIGHT. SOME DIURNAL CU
IS AGAIN EXPECTED TOMORROW AFTERNOON AT KIWD/KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 AM EDT WED AUG 14 2013
A RIDGE OF HIGH PRESSURE SHOULD BE THE RULE THROUGH THE UPCOMING
WEEKEND...RESULTING IN RELATIVLY LIGHT WINDS. LARGE HIGH PRESSURE
STRETCHING FROM SOUTH CENTRAL CANADA THROUGH THE UPPER GREAT LAKES
AND MID MISSISSIPPI VALLEY WILL SLOWLY SINK ACROSS THE OHIO VALLEY
AND MID ATLANTIC STATES ON THURSDAY. THE EVER-PRESENT AREA OF HIGH
PRESSURE WILL THEN EXPAND NORTHWARD TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES ON THURSDAY NIGHT THROUGH SUNDAY. EXPECT A TROUGH TO
SET UP OVER THE NORTHERN PLAINS INTO MANITOBA ON SUNDAY...WITH WIND
GUSTS STILL AROUND 20KTS OR LESS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...JLB
AVIATION...SRF
MARINE...KF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
257 PM CDT Wed Aug 14 2013
.SHORT TERM...(This Evening through Friday Afternoon)
Issued at 257 PM CDT WED AUG 14 2013
The main focus in the short-term remains a series of shortwave
troughs sinking southeastward across the Plains this evening,
Thursday, and into early Friday. Showers and isolated storms have
developed over portions of eastern Nebraska in association with a
wave currently pushing southeast toward the forecast area; however,
ongoing precipitation will continue to move into fairly dry air this
evening, and may struggle against entrainment. Additionally, upper-
level flow may push the main area of precipitation more east than
south, keeping the bulk of any falling precipitation in central and
southern Iowa. Short-term precipitation trends from the HRRR have
been fairly consistent today, and also generally limit the south and
eastward expansion of showers for this evening and tonight. For now,
have kept PoPs very low and confined to far northwest Missouri prior
to 06z, then have begun to increase chances in the NW to account for
possible regeneration as the low-level jet kicks up early Thursday
morning.
The next system will follow on the heels of tonight`s as it drops
down from eastern Montana on Thursday. Models continue to indicate
that the reinforcement of the eastern trough by a second upper low,
and the retrograding of a broad upper high, will result in more
meridional flow across the Plains for Thursday and Friday. This
subtle change will send the second wave a bit west of the forecast
area, keeping the better rain chances mainly across portions of
central and eastern Kansas. Have left some slight to low-end chance
PoPs mainly across the western tier or two of counties on Thursday
afternoon and Thursday night, but these could likely be cut further
if model trends continue in this direction. Any precipitation that
does brush the area will sink southward on Friday morning, leaving
behind quiet conditions by Friday afternoon.
Temperatures through the period will remain ~10 degrees below normal
as cool air continues to filter down the trough and into the eastern
Plains and Ohio River valley, with highs generally topping out in
the upper 70s to lower 80s, and lows in the 50s to lower 60s under
surface high pressure.
.LONG TERM...(Friday Evening through Wednesday)
Issued at 257 PM CDT WED AUG 14 2013
A quiet medium range forecast for the Central Plains as mid-level
ridging currently building over the Rockies begins to move
eastward. Despite the increasing heights, Saturday will likely
remain below seasonal normals as surface and low-level winds remain
light to southeast. By Sunday, we`ll begin to see a steady climb
back to or even above normal as winds turn southerly and warmer air
begins to advect northward.
The first half of next week will again feature quiet conditions as
mid-level flow remains weak. Temperatures will have a chance to
return to the 90 degree mark by Tuesday and Wednesday, a rare feat
this August.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1222 PM CDT WED AUG 14 2013
VFR conditions are expected to prevail across the majority of the
region through the forecast period. A midlevel stratus deck with
bases around 4-5 kft and a few isolated showers may begin to work
into far northwest MO around sunrise Thursday, but should not impact
flight category.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Laflin
LONG TERM...Dux
AVIATION...Laflin
AREA FORECAST DISCUSSION
NWS HASTINGS NE
354 PM CDT WED AUG 14 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
CLOUDS LINGERED ACROSS MUCH OF THE AREA THIS AFTERNOON AND HAS SO
FAR HELPED TO PUT A CAP ON MORE WIDESPREAD CONVECTION. THAT
SAID...INSTABILITY IS BEGINNING TO BUILD...AND WITH SOME NOTABLE
MOISTURE CONVERGENCE AHEAD OF DEVELOPING CONVECTION TO OUR
NORTH...EXPECT THE POTENTIAL FOR ADDITIONAL DEVELOPMENT THROUGH
THE LATE AFTERNOON AND EVENING HOURS. MODELS HAVE NOT HAD A GREAT
HANDLE ON THIS ALL DAY...ALBEIT 12Z WRF AND LATEST HRRR BOTH
ATTEMPTED TO PICK UP ON CONVECTION TO OUR NORTH...TAKING IT
SOUTHWARD THROUGH THE EVENING HOURS. WHILE CONFIDENCE IS NOT
PARTICULARLY HIGH...CONTINUE TO SEE THE POTENTIAL FOR SOME
ADDITIONAL THUNDERSTORM ACTIVITY THROUGH THE EVENING AND INTO THE
OVERNIGHT HOURS AS THERE IS PLENTY OF INSTABILITY TO
TAP...ESPECIALLY WEST OF HIGHWAY 281. THAT SAID...SHEAR IS VERY
WEAK...AND ANY ADDITIONAL STORMS THAT DO DEVELOP ARE NOT EXPECTED
TO BE SEVERE OR WIDESPREAD.
AS WE WORK TOWARDS THURSDAY MORNING AND FOCUS OF INITIAL
CONVECTION SHIFTS SOUTHWARD...COULD SEE SOME PARTIAL
CLEARING...AND WITH LIGHT SOUTHEASTERLY WINDS AND ELEVATED LOW
LEVEL MOISTURE...DECIDED TO INSERT PATCHY FOG INTO THE FORECAST
FOR THE EARLY MORNING HOURS TOMORROW. LATEST HRRR IS INDICATING
POSSIBLY SOME DENSE FOG ACROSS OUR NORTH BY 09Z...BUT WITH
UNCERTAINTY IN TIMING AND AMOUNT OF CLEARING...PATCHY MENTION
SEEMED MORE REASONABLE FOR THE TIME BEING.
AS WE WORK INTO THE DAYTIME HOURS THURSDAY...THE POTENTIAL FOR
SOME STRONG/MARGINALLY SEVERE STORMS WILL BE REALIZED BY EARLY
AFTERNOON AS MODELS ARE PICKING UP ON AN UPPER LEVEL SHORTWAVE
DROPPING DOWN FROM THE NORTH COUPLED WITH THE PRESENCE OF A WEAK
WARM FRONTAL BOUNDARY DRAPED ACROSS THE LOCAL AREA FROM NORTHWEST
TO SOUTHEAST. THIS COMBINATION...WITH PLENTY OF AVAILABLE
INSTABILITY...SHOULD MAKE FOR A MORE ACTIVE AFTERNOON AND
EVENING...AND CONTINUED WITH MENTION OF POTENTIAL SEVERE WEATHER
IN HWO THIS AFTERNOON. WHILE SHEAR IS NOT ALL THAT
IMPRESSIVE...CAPE AND FORCING SHOULD BE SUFFICIENT FOR THE
DEVELOPMENT OF A FEW STORMS WITH MARGINALLY SEVERE HAIL AND
THUNDERSTORM WIND GUSTS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED AUG 14 2013
THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE
PERIOD AND TEMPERATURES.
AN UPPER LEVEL WAVE WILL CONTINUE TO MOVE THROUGH THE AREA THURSDAY
NIGHT. THUNDERSTORMS WILL CONTINUE ACROSS THE AREA DURING THE
EVENING BUT GRADUALLY COME TO AN END FROM NORTHWEST TO SOUTHEAST
DURING THE OVERNIGHT HOURS AND INTO FRIDAY MORNING. MUCAPE REMAINS
AROUND 3000 J/KG DURING THE EVENING BUT DROPS OFF LATER IN THE
NIGHT. ON FRIDAY THE UPPER LEVEL RIDGE IN THE ROCKIES STARTS TO
SLIDE TO THE EAST AND WITH THE RAIN MOVING OUT...TEMPERATURES WILL
WARM SOME.
FRIDAY NIGHT INTO SUNDAY THE UPPER LEVEL RIDGE BUILDS ACROSS THE
AREA AND EXPECT DRY CONDITIONS AND TEMPERATURES WILL CONTINUE TO
WARM A FEW DEGREES.
AN UPPER LEVEL WAVE WILL MOVE OVER THE RIDGE SUNDAY NIGHT AND BRING
A SMALL CHANCE FOR THUNDERSTORMS. THERE SHOULD BE A BRIEF BREAK FROM
THUNDERSTORMS AGAIN ON MONDAY BUT ANOTHER UPPER LEVEL WAVE MOVES
INTO THE AREA MONDAY NIGHT AND TUESDAY. THERE IS ALSO A WEAK COLD
FRONT THAT MOVES THROUGH THE FORECAST AREA MONDAY NIGHT.
THUNDERSTORMS ARE EXPECTED ALONG AND BEHIND THE COLD FRONT. DESPITE
THE COLD FRONT TEMPERATURES SHOULD CONTINUE TO WARM A DEGREE OR TWO
EACH DAY AS THE UPPER RIDGE SETTLES OVER THE PLAINS.
TUESDAY NIGHT AND WEDNESDAY THE MODELS HAVE SOME DIFFERENCES IN THE
MAIN PATTERN. THE GFS HAS AN UPPER RIDGE...WHILE THE ECMWF HAS A
TROUGH MOVING THROUGH. WILL HAVE A SMALL CHANCE FOR THUNDERSTORMS
FOR NOW. THE TEMPERATURE SHOULD REMAIN ABOVE NORMAL.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1235 PM CDT WED AUG 14 2013
PREVAILING VFR CONDS ARE EXPECTED AT KGRI THROUGH THE AFTERNOON
HOURS AS PLENTY OF MID LEVEL CLOUD COVER CONTINUES TO STREAM
ACROSS THE REGION. WILL LIKELY SEE SOME BREAKS IN THIS CLOUD COVER
FROM TIME TO TIME...WHICH COULD ALLOW INSTABILITY TO BUILD...AND
KEPT MENTION OF A VCTS AFT 15/00Z AS A BAND OF SHOWERS AND
THUNDERSTORMS COULD DEVELOP IN RESPONSE TO THIS BUILDING
INSTABILITY AND FORCING FROM A WEAK APPROACHING SHORT WAVE.
OTHERWISE...STILL EXPECT SKIES TO CLEAR SOMEWHAT DURING THE LATE
OVERNIGHT HOURS...AND THIS CLEARING COMBINED WITH LIGHT
SOUTHEASTERLY WINDS AND SATURATED LOW LEVELS...COULD RESULT IN
SOME MVFR OR LOWER VSBYS AND CIGS TOWARDS DAY BREAK. ANY FOG THAT
DOES DEVELOP...HOWEVER...IS EXPECTED TO BE SHORT LIVED...AND A
RETURN TO VFR CONDITIONS IS EXPECTED AFT 15/13Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...JCB
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1243 PM CDT WED AUG 14 2013
.UPDATE...
ISSUED AT 1021 AM CDT WED AUG 14 2013
MADE A FEW CHANGES TO POP/WX/SKY AND ALSO TEMPS IN THE NORTHEAST
FOR TODAY. LATEST TRENDS SHOW REMNANTS FROM THE OVERNIGHT MCS
STILL LINGERING IN THE NORTHEAST. THIS LOOKS TO BE A FAVORABLE
AREA FOR SHOWERS TO CONTINUE INTO THE EARLY AFTERNOON HOURS AS
INDICATED BY THE 12Z NAM...ALTHOUGH THE NAM IS A BIT SLOW. THIS
AFTERNOON... THUNDERSTORM CHANCES GET A LITTLE MORE NEBULOUS AS
NAM POINTS TOWARD ACTIVITY CONTINUING IN THE NORTHEAST...AND ONLY
FAVORS ISOLATED ACTIVITY IN THE FAR WEST. THE 06Z GFS KEEPS THE
WHOLE EASTERN CWA ACTIVE...AS DOES THE 09Z SREF. MADE SLIGHT
ADJUSTMENTS BASED ON LATEST TRENDS...BUT WILL CONTINUE TO EVALUATE
12Z MODEL SUITE AND EFFECTS OF MORNING CONVECTION BEFORE MAKING
MAJOR CHANGES FOR THIS AFTERNOON. WILL ALSO MONITOR FOR SEVERE
THREAT AS SHEAR LOOKS A LITTLE BETTER THAN YESTERDAY ACROSS THE
AREA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT WED AUG 14 2013
IN THE VERY NEAR TERM MESOSCALE CONVECTIVE VORTICITY (MCV) MOVING
ACROSS NORTHERN NEBRASKA. HRRR MODEL WANTS TO DEVELOP MORE
CONVECTION INTO SOUTHWEST NEBRASKA THROUGH THE EARLY MORNING BUT
RADAR TRENDS SHOWING THAT FORCING DIMINISHING OVER SOUTHWEST
NEBRASKA. HAVE CONTINUED LIKELY POPS OVER NORTH CENTRAL NEBRASKA
WITH CHANCES SLOWLY TAPERING DOWN TO SLIGHT CHANCE AS THE SYSTEM
MOVES EAST. CHANCE POPS BROUGHT BACK INTO ENTIRE FORECAST AREA
THIS AFTERNOON AS A WAVE MOVES SOUTHEAST ACROSS FORECAST AREA FROM
SOUTH DAKOTA. TEMPERATURES TODAY WILL BE SKEWED BY MCV AND CLOUD
SHIELD OVER NORTH CENTRAL NEBRASKA WITH HIGH AT ONEILL 74 DEGREES.
80S TO THE WEST AND SOUTHWEST WHERE PARTLY TO MOSTLY CLOUDY SKIES
SEEN. FAIRLY ROBUST SOUTHERLY FLOW THIS AFTERNOON WITH DEW POINTS
AROUND 60. TIMING OF WAVES WILL BE KEY TO PRECIPITATION CHANCES.
LOW LEVEL JET TONIGHT WILL HELP TO SUSTAIN CONVECTION FROM THE
AFTERNOON AND HELP TO CARRY IT ACROSS THE FORECAST AREA. COOLER
TEMPERATURES AGAIN WITH LOWS BY SUNRISE IN THE MID TO UPPER 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CDT WED AUG 14 2013
A SHORTWAVE TROUGH WILL ROTATE SOUTHEAST ACROSS THE AREA THURSDAY
ON THE EASTERN PERIPHERY OF THE ROCKIES UPPER LEVEL RIDGE.
SCATTERED AFTERNOON THUNDERSTORMS ARE POSSIBLE AS THIS FEATURE
ROTATES SOUTHEAST ACROSS THE AREA. STEEP LOW AND MID LEVEL LAPSE
RATES COMBINED WITH AMPLE MOISTURE...SHOULD YIELD MODERATE TO
LOCALLY STRONG INSTABILITY BY AFTERNOON. NORTHWEST FLOW ALOFT WILL
INCREASE...AND WHEN COMBINED WITH WEAK EAST TO SOUTHEAST FLOW AT
THE SURFACE...DECENT BULK SHEAR OF 35 TO 45 KTS WILL LIKELY
SUPPORT A FEW SOUTHEAST MOVING SUPERCELLS WITH THE POTENTIAL FOR
LARGE HAIL.
AFTER THURSDAY...THE UPPER LEVEL RIDGE WILL AMPLIFY AND BUILD
NORTHEAST OVER THE AREA...BRINGING A SPELL OF DRY WEATHER FRIDAY
THROUGH SUNDAY. TEMPERATURES WILL SLOWLY WARM DURING THIS
PERIOD...WITH HIGHS RANGING FROM THE LOWER TO MID 80S FRIDAY...TO
THE MID AND UPPER 80S SUNDAY.
EARLY NEXT WEEK THE UPPER LEVEL RIDGE REMAINS ANCHORED OVER THE
AREA. MODELS ARE TRYING TO BRING A DISTURBANCE THROUGH THE REGION
ON THE SOUTHERN FRINGES OF THE NORTHERN STREAM. CONFIDENCE IS LOW
AT THIS POINT REGARDING THE TIMING AND STRENGTH OF THIS
DISTURBANCE. HAVE KEPT ANY CHANCES FOR PRECIPITATION LOW...AND
HAVE KEPT TEMPERATURES WARM WITH THE UPPER LEVEL RIDGE IN CONTROL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1243 PM CDT WED AUG 14 2013
FORECAST FOR THE TAF SITES INCLUDES LINGERING MVFR CIGS LIFTING TO
VFR THIS THIS AFTERNOON. KLBF AND KVTN CIGS SHOULD BE LIFTING EARLY
IN THE AFTERNOON. SOME VFR CUMULUS WILL LIKELY BE DEVELOPING BY
MID AFTERNOON...WITH POSSIBLY SOME THUNDERSTORM ACTIVITY IN THE
REGION. CONFIDENCE IS RATHER LOW TO PUT IN THE TAF AT THIS TIME.
TONIGHT...MODELS HAVE INDICATED LOW LEVEL MOISTURE WILL BE IN
PLACE FOR LIGHT FOG/MIST LATE TONIGHT. HOWEVER...SOME INCREASING
CLOUDS FROM THE NORTHWEST MAY INHIBIT DEVELOPMENT LATE IN THE
NIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KNUTSVIG
SHORT TERM...POWER
LONG TERM...TAYLOR
AVIATION...KNUTSVIG
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
321 PM CDT WED AUG 14 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
PRETTY QUIET ACROSS THE CWA THIS AFTERNOON BUT WILL BE WATCHING
THE WESTERN CWA OVER THE NEXT FEW HOURS FOR THE POTENTIAL FOR A
FEW ISOLD THUNDERSHOWERS AS SHORTWAVE ENERGY APPROACHES FROM THE
MIDWEST. BEST SUPPORT DOES NOT ARRIVE UNTIL LATER THIS
EVENING...BUT DAYTIME HEATING ACROSS THE WESTERN CWA HAS ALLOWED
MLCAPE TO APPROACH 1000 J/KG. SHEAR IS LACKING ONCE AGAIN AS HAS
BEEN THE CASE THE PAST FEW DAYS. CURRENTLY SEEING A CONGESTED CU
FIELD ACROSS NORTH CENTRAL SD WITH RADAR ECHOES JUST BEGINNING TO
INCREASE OVER CORSON COUNTY. HRRR ACTUALLY PICKING UP ON THIS AND
SHOWING A FEW POPCORN TYPE LIGHT SHOWERS OR MAYBE A MODERATE
THUNDERSHOWER THROUGH LATE AFTERNOON. WILL MAINTAIN SLIGHT CHANCE
POPS FOR THE WESTERN CWA THROUGH THE AFTERNOON. MAIN SHORTWAVE
ENERGY APPROACHES THE REGION LATER THIS EVENING...BUT MODELS NOT
TOO IMPRESSED WITH THIS FOR OUR CWA. 12Z NSSL WRF SHOWS A LINE OF
SHOWERS AND STORMS MOVING INTO WESTERN SD LATER THIS EVENING BUT
DIES OUT AS ITS ENTERING THE WESTERN CWA. WILL MAINTAIN SMALL POPS
OVERNIGHT AS WELL...BUT HAVE TRIMMED THINGS DOWN TO DRY FOR THE
EASTERN CWA AS THERE JUST DOESNT SEEM TO BE ANY SUPPORT FOR
PRECIP. THERE REALLY IS NO LOW LEVEL JET TO SPEAK OF OVERNIGHT
EITHER.
WEAK SHORTWAVE ENERGY MOVES SOUTHEAST OVER THE AREA ON THURSDAY
BUT MODELS KEEP TRENDING DRIER AND DRIER FOR THIS...TO THE POINT
NOW WHERE MOST MODELS ARENT EVEN SHOWING ANY PRECIP FOR THE AREA.
HAVE SCALED BACK POPS QUITE A BIT...GOING DRY IN PLACES BUT
KEEPING A SLIGHT CHANCE GOING FOR MOST PLACES. AFTER
THURSDAY...THE WARM UP BEGINS AS UPPER RIDGING BUILDS OVER THE
HIGH PLAINS AND DAKOTAS.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
MAIN CHALLENGE IN THE LONG TERM WILL BE PRECIP CHANCES UNDER THE
DOMINANT UPPER RIDGE.
MODELS ARE NOT IN GOOD AGREEMENT TODAY IN THE EXTENDED. TOSSED OUT
THE GEM AS IT IS THE ONLY MODEL SHOWING A DEVELOPING TROPICAL
SYSTEM IN THE GULF THIS WEEKEND. THIS MAY CONTAMINATE QPF AND
PRESSURE FIELDS ALL THE WAY NORTH INTO THE DAKOTAS. GFS AND ECMWF
ARE BOTH FLIP FLOPPING WITH MOISTURE FIELDS THOUGH SFC PRESSURE
PROGS ARE SIMILAR. BOTH MODELS SHOW TWO TROFS MOVING ACROSS THE
DAKOTAS...ONE SUNDAY NIGHT/MONDAY AND ANOTHER TUESDAY
NIGHT/WEDNESDAY. HOWEVER THE GFS IS WET FOR THE FIRST AND DRY FOR
THE SECOND WHILE THE ECMWF IS OPPOSITE. STUCK WITH ALLBLEND POPS
SUNDAY NIGHT/MONDAY AS 30S/40S SEEM REASONABLE AT THIS POINT. WENT
DRIER THAN ALLBLEND FOR THE END OF THE PERIOD BASED ON INTER
OFFICE COLLABORATION.
TEMPERATURES SHOULD BE ON THE RISE THROUGH THE PERIOD WITH HIGHS
IN THE UPPER 80S TO LOWER 90S EXPECTED.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL FOR ALL TERMINALS THROUGH THIS
EVENING. ISOLATED SHOWERS AND TSTORMS ARE POSSIBLE OVERNIGHT NEAR
KPIR. THIS ADDED MOISTURE WILL LIKELY RESULT IN LIGHT FOG
DEVELOPMENT CAUSING MVFR CIGS/VSBY. MVFR CONDITIONS SHOULD LIFT TO
VFR THURSDAY MORNING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1221 PM CDT WED AUG 14 2013
.AVIATION...
AFTN SHRA AND TSRA LIKELY TO BE TOO SCATTERED TO CONFIDENTLY PUT A
TEMPO GROUP IN EITHER TAF...BUT THERE WILL BE SOME AROUND...
POSSIBLY BUILDING SWD FROM AN AREA OF SCATTERED TSRA CURRENTLY
ACROSS THE WRN PANHANDLE. FOCUS THEN SHIFTS TO LATE EVENING WITH
POTENTIAL FOR ANOTHER TS COMPLEX MOVING OUT OF NERN NM. CONFIDENCE
HIGH ENOUGH OF THIS POSSIBLITY TO CONTINUE RUNNING WITH A PROB30
IN BOTH TAFS. SOME CHANCE ON CIG RESTRICTIONS TOWARD SUNRISE
DEPENDING A LOT ON WHETHER THIS LATTER COMPLEX DEVELOPS AND MOVES
THROUGH THE FCST AREA. ATTM WILL MAINTAIN MORE OPTIMISTIC FCST
WITH CIGS IN VFR CATEGORY.
&&
.PREV DISCUSSION... /ISSUED 1113 AM CDT WED AUG 14 2013/
UPDATE...
MINOR UPDATE TO BE ISSUED MAINLY TO CATCH UP TO DIURNAL TRENDS.
LINGERING LIGHT RAIN IN THE SOUTH SHOULD QUICKLY DISSIPATE...BUT A
NARROW BAND OF ISOLATED SHOWERS AND THUNDERSTORMS ALREADY
DEVELOPING ACROSS THE WRN PANHANDLE IN AN AREA OF MOIST UPSLOPE
FLOW. THE HRRR SEEMS TO PICK UP ON THIS TREND THE BEST AND
GENERALLY LEAVES IT AS A DISORGANIZED AREA OF ISOLATED TO
SCATTERED CONVECTION. THIS MODELS FOCUS FOR ORGANIZED CONVECTION
IS AGAIN WITH CONVECTION PROGGED TO DEVELOP ACROSS NERN NM. UPPER
FLOW AGAIN PROGGED TO BE RELATIVELY ROBUST FOR THIS TIME OF
YEAR...ON THE ORDER OF 25-35 KTS AT 500 MB...WITH MODEST BUT MOIST
LOW LEVEL EASTERLY COMPONENT TO THE WINDS. PROGGED LOW LEVEL
THETA-E AXIS LATE THIS AFTN THROUGH THE EVENING RUNS BASICALLY
DOWN US 84 FROM CLOVIS TO SNYDER. ADJUSTMENTS TO POPS WILL BE TO
NUDGE UPWARD TO AROUND 40 PCT ACROSS THE NWRN ZONES WITH 30 PCT
ELSEWHERE. WILL LEAVE THE EVENING POPS AS IS FOR NOW AND
REEVALUATE THIS AFTERNOON. SHOULD ANOTHER GOOD BATCH OF CONVECTION
DEVELOP UPSTREAM WILL LIKELY INCREASE POPS FOR TONIGHT.
PREV DISCUSSION... /ISSUED 628 AM CDT WED AUG 14 2013/
AVIATION...
VFR CONDITIONS ARE HOLDING IN AT KLBB WHILE MVFR CEILINGS HAVE
DEVELOPED AT KCDS. THERE STILL IS A POTENTIAL THAT KLBB COULD DROP
INTO MVFR BY SUNRISE BUT CONFIDENCE WAS NOT HIGH ENOUGH TO ADD TO
THE TAFS AT THIS TIME. SHOULD SEE VFR CONDITIONS BY LATE MORNING
AT BOTH TERMINALS. STILL IS QUITE A BIT OF UNCERTAINTY IF WE WILL
SEE ANOTHER ROUND OF THUNDERSTORMS AT EITHER OF THE TERMINALS LATE
TONIGHT INTO EARLY THURSDAY MORNING BUT CONFIDENCE IS HIGH ENOUGH
TO INCLUDE PROB30 GROUPS AT BOTH SITES. THERE MAY BE SOME CHANGES
IN THE TIMING IN THE TAFS AS WE SEE HOW CONDITIONS CHANGE THROUGH
THE DAY.
JORDAN
PREV DISCUSSION... /ISSUED 438 AM CDT WED AUG 14 2013/
SHORT TERM...
BUSY START TO THIS SET OF MIDNIGHT SHIFTS AS AN ONGOING COMPLEX OF
THUNDERSTORMS OFF THE CAPROCK AND OVER THE ROLLING PLAINS HAS
PRODUCED SOME IMPRESSIVE RAINFALL AMOUNTS. THE HIGHEST THAT WE HAVE
SEEN WAS NEARLY 5 INCH PER HOUR RAINFALL RATES AT THE WEST TEXAS
MESONET STATION IN POST SHORTLY AFTER 315 AM. ALSO SEEING SIMILAR
RAINFALL RATES AT THE GUTHRIE MESONET SITE RIGHT BEFORE 4 AM.
FLOODING REPORTS HAVE BEEN HARD TO COME BY AT THIS TIME OF NIGHT AND
FORTUNATELY THE BULK OF THE STORMS HAVE BEEN ACROSS SPARSELY
POPULATED AREAS. HOWEVER...SOME UNLUCKY CITIES SUCH AS POST HAVE
BEEN ON THE RECEIVING END OF THE RAINFALL. FORECAST-WISE...THE
ONGOING ACTIVITY ALSO POSES A PROBLEM WITH THE FORECAST TODAY.
STORMS HAVE CONTINUED TO TRY AND REDEVELOP ACROSS EASTERN NEW MEXICO
AS A SERIES OF WEAK SHORTWAVES MOVES OVER THE REGION IN
NORTHWESTERLY FLOW ALOFT.
BIGGEST CONCERN FOR ADDITIONAL CONVECTION TODAY AND TONIGHT IS HOW
MUCH MORE STABLE THE ATMOSPHERE WILL BE WITH THE DEPARTING SERIES OF
STORMS. ON THE OTHER HAND...11-3.9 MICRON IMAGERY SHOWS LITTLE IN
THE WAY OF UPSTREAM CLOUD COVER AND DECENT VENTING OF THE CURRENT
CLOUD COVER OUT OF THE REGION SO WE MAY PICK UP SOME DAYTIME HEATING
WHICH COULD LEAD TO DESTABILIZATION LATER IN THE DAY ACROSS THE
AREA. MODELS ARE NOT VERY CONSISTENT WITH THE COVERAGE OR
DEVELOPMENT OF CONVECTION LATER TODAY SO A LOT WILL DEPEND ON HOW
THINGS UNFOLD THIS MORNING. THERE IS TO AN EXTENT SOME AGREEMENT OF
ANOTHER SHORTWAVE MOVING ACROSS THE AREA BUT THE TIMING REMAINS
HIGHLY VARIABLE WITH THE NAM PUSHING THIS ACROSS BY THIS AFTERNOON
WHILE THE GFS/ECMWF ARE LATER IN THE DAY/EARLY IN THE EVENING. DID
TAPER OFF POPS SOME THIS MORNING FOR THE 7AM-1PM TIME FRAME AS
CURRENT ACTIVITY PUSHES OUT OF THE AREA. HOWEVER...UNCERTAINTY ON
HOW THINGS WILL UNFOLD HIS AFTERNOON KEPT POPS IN THE LOW TO
MID-RANGE CHANCE FOR NOW. AMPLE MOISTURE WILL STILL BE ACROSS THE
REGION SO LOCALLY HEAVY RAINFALL COULD BE EXPECTED AGAIN WITH THE
STRONGER OF ANY STORMS THAT DEVELOP. MILD TEMPERATURES CAN BE
EXPECTED TODAY THANKS TO EARLY CLOUD COVER AND THE RAINFALL EARLY
THIS MORNING.
JORDAN
LONG TERM...
ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM GIVEN THE RATHER BUSY
SHORT TERM. UNSETTLED WEATHER STILL APPEARS IN THE CARDS FOR WEST
TEXAS THROUGH LATE WEEK AS NORTHWESTERLY FLOW ALOFT PREVAILS AND A
FRONTAL BOUNDARY AND RICH MOISTURE /HIGH THETA-E AIR/ LINGERS.
TRICKY PART REMAINS PICKING OUT THE SUBTLE DETAILS INCLUDING THE
TIMING OF ANY SHORTWAVES THAT MAY ENHANCE RAIN CHANCES AND
DETERMINING THE EXACT POSITION OF THE LOW-LEVEL FOCUSES THAT MAY
HELP GUIDE WHERE THE BEST RAIN CHANCES WILL BE DURING ANY PERIOD.
THAT SAID...THERE IS DECENT AGREEMENT THAT A PRONOUNCED SHORTWAVE
TROUGH WILL APPROACH FROM WESTERN KANSAS LATE THURSDAY INTO EARLY
FRIDAY AND THIS MAY PROVIDED AN ENHANCED PERIOD FOR STORM
CHANCES...PERHAPS FAVORING THE EASTERN ZONES. A RENEWED SURGE OF
EASTERLY LOW-LEVEL FLOW MAY FOLLOW WITH THE MOIST UPSLOPE FLOW
JUSTIFYING MAINTAINING AT LEAST LOW POPS FRIDAY AFTERNOON/EVENING.
BY THIS TIME THE UPPER FLOW WILL TURN MERIDIONAL...MAKING IT
DIFFICULT FOR CONVECTION ORIGINATING OVER THE MOUNTAINS OF NM/CO
TO MAKE IT INTO THE SOUTH PLAINS THOUGH. THROUGH THIS LATE WEEK
PERIOD...0-6 KM SHEAR WILL BE DECENT /AROUND 30 KNOTS/ AND IF
SUFFICIENT HEATING/INSTABILITY CAN MATERIALIZE...A FEW OF THE
STORMS COULD BE STRONG OR SEVERE. IN ADDITION...ELEVATED MOISTURE
LEVELS ARGUE FOR A HEAVY RAIN THREAT TOO.
WE SHOULD SEE A DRYING TREND AFTER FRIDAY AS THE UPPER FLOW TURNS
MORE NORTHERLY AND ADVECTS IN DRIER AIR ALOFT...THOUGH THE LOW-LEVEL
THETA-E RIDGE MAY PERSIST NEARBY AND COULD KEEP A FEW SHOWER CHANCES
IN THE PICTURE IF THE ECMWF IS CORRECT. THE FLOW WILL FURTHER VEER
TO NORTHEASTERLY EARLY NEXT WEEK WITH DRY CONDITIONS LIKELY TO
CONTINUE. TEMPERATURES SHOULD REMAIN NEAR OR SLIGHTLY BELOW AVERAGE
THROUGH MUCH OF THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 82 61 86 62 87 / 40 40 30 30 20
TULIA 81 62 85 63 85 / 30 40 30 40 20
PLAINVIEW 80 63 87 65 88 / 30 40 30 40 20
LEVELLAND 81 64 88 65 92 / 30 40 30 30 20
LUBBOCK 82 65 88 67 90 / 30 40 30 30 20
DENVER CITY 83 66 89 67 94 / 40 30 30 30 20
BROWNFIELD 83 66 90 66 93 / 40 30 30 30 20
CHILDRESS 85 67 89 68 89 / 30 40 30 40 20
SPUR 83 68 90 68 94 / 30 40 30 40 20
ASPERMONT 84 69 89 71 93 / 40 30 30 30 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1113 AM CDT WED AUG 14 2013
.UPDATE...
MINOR UPDATE TO BE ISSUED MAINLY TO CATCH UP TO DIURNAL TRENDS.
LINGERING LIGHT RAIN IN THE SOUTH SHOULD QUICKLY DISSIPATE...BUT A
NARROW BAND OF ISOLATED SHOWERS AND THUNDERSTORMS ALREADY
DEVELOPING ACROSS THE WRN PANHANDLE IN AN AREA OF MOIST UPSLOPE
FLOW. THE HRRR SEEMS TO PICK UP ON THIS TREND THE BEST AND
GENERALLY LEAVES IT AS A DISORGANIZED AREA OF ISOLATED TO
SCATTERED CONVECTION. THIS MODELS FOCUS FOR ORGANIZED CONVECTION
IS AGAIN WITH CONVECTION PROGGED TO DEVELOP ACROSS NERN NM. UPPER
FLOW AGAIN PROGGED TO BE RELATIVELY ROBUST FOR THIS TIME OF
YEAR...ON THE ORDER OF 25-35 KTS AT 500 MB...WITH MODEST BUT MOIST
LOW LEVEL EASTERLY COMPONENT TO THE WINDS. PROGGED LOW LEVEL
THETA-E AXIS LATE THIS AFTN THROUGH THE EVENING RUNS BASICALLY
DOWN US 84 FROM CLOVIS TO SNYDER. ADJUSTMENTS TO POPS WILL BE TO
NUDGE UPWARD TO AROUND 40 PCT ACROSS THE NWRN ZONES WITH 30 PCT
ELSEWHERE. WILL LEAVE THE EVENING POPS AS IS FOR NOW AND
REEVALUATE THIS AFTERNOON. SHOULD ANOTHER GOOD BATCH OF CONVECTION
DEVELOP UPSTREAM WILL LIKELY INCREASE POPS FOR TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 628 AM CDT WED AUG 14 2013/
AVIATION...
VFR CONDITIONS ARE HOLDING IN AT KLBB WHILE MVFR CEILINGS HAVE
DEVELOPED AT KCDS. THERE STILL IS A POTENTIAL THAT KLBB COULD DROP
INTO MVFR BY SUNRISE BUT CONFIDENCE WAS NOT HIGH ENOUGH TO ADD TO
THE TAFS AT THIS TIME. SHOULD SEE VFR CONDITIONS BY LATE MORNING
AT BOTH TERMINALS. STILL IS QUITE A BIT OF UNCERTAINTY IF WE WILL
SEE ANOTHER ROUND OF THUNDERSTORMS AT EITHER OF THE TERMINALS LATE
TONIGHT INTO EARLY THURSDAY MORNING BUT CONFIDENCE IS HIGH ENOUGH
TO INCLUDE PROB30 GROUPS AT BOTH SITES. THERE MAY BE SOME CHANGES
IN THE TIMING IN THE TAFS AS WE SEE HOW CONDITIONS CHANGE THROUGH
THE DAY.
JORDAN
PREV DISCUSSION... /ISSUED 438 AM CDT WED AUG 14 2013/
SHORT TERM...
BUSY START TO THIS SET OF MIDNIGHT SHIFTS AS AN ONGOING COMPLEX OF
THUNDERSTORMS OFF THE CAPROCK AND OVER THE ROLLING PLAINS HAS
PRODUCED SOME IMPRESSIVE RAINFALL AMOUNTS. THE HIGHEST THAT WE HAVE
SEEN WAS NEARLY 5 INCH PER HOUR RAINFALL RATES AT THE WEST TEXAS
MESONET STATION IN POST SHORTLY AFTER 315 AM. ALSO SEEING SIMILAR
RAINFALL RATES AT THE GUTHRIE MESONET SITE RIGHT BEFORE 4 AM.
FLOODING REPORTS HAVE BEEN HARD TO COME BY AT THIS TIME OF NIGHT AND
FORTUNATELY THE BULK OF THE STORMS HAVE BEEN ACROSS SPARSELY
POPULATED AREAS. HOWEVER...SOME UNLUCKY CITIES SUCH AS POST HAVE
BEEN ON THE RECEIVING END OF THE RAINFALL. FORECAST-WISE...THE
ONGOING ACTIVITY ALSO POSES A PROBLEM WITH THE FORECAST TODAY.
STORMS HAVE CONTINUED TO TRY AND REDEVELOP ACROSS EASTERN NEW MEXICO
AS A SERIES OF WEAK SHORTWAVES MOVES OVER THE REGION IN
NORTHWESTERLY FLOW ALOFT.
BIGGEST CONCERN FOR ADDITIONAL CONVECTION TODAY AND TONIGHT IS HOW
MUCH MORE STABLE THE ATMOSPHERE WILL BE WITH THE DEPARTING SERIES OF
STORMS. ON THE OTHER HAND...11-3.9 MICRON IMAGERY SHOWS LITTLE IN
THE WAY OF UPSTREAM CLOUD COVER AND DECENT VENTING OF THE CURRENT
CLOUD COVER OUT OF THE REGION SO WE MAY PICK UP SOME DAYTIME HEATING
WHICH COULD LEAD TO DESTABILIZATION LATER IN THE DAY ACROSS THE
AREA. MODELS ARE NOT VERY CONSISTENT WITH THE COVERAGE OR
DEVELOPMENT OF CONVECTION LATER TODAY SO A LOT WILL DEPEND ON HOW
THINGS UNFOLD THIS MORNING. THERE IS TO AN EXTENT SOME AGREEMENT OF
ANOTHER SHORTWAVE MOVING ACROSS THE AREA BUT THE TIMING REMAINS
HIGHLY VARIABLE WITH THE NAM PUSHING THIS ACROSS BY THIS AFTERNOON
WHILE THE GFS/ECMWF ARE LATER IN THE DAY/EARLY IN THE EVENING. DID
TAPER OFF POPS SOME THIS MORNING FOR THE 7AM-1PM TIME FRAME AS
CURRENT ACTIVITY PUSHES OUT OF THE AREA. HOWEVER...UNCERTAINTY ON
HOW THINGS WILL UNFOLD HIS AFTERNOON KEPT POPS IN THE LOW TO
MID-RANGE CHANCE FOR NOW. AMPLE MOISTURE WILL STILL BE ACROSS THE
REGION SO LOCALLY HEAVY RAINFALL COULD BE EXPECTED AGAIN WITH THE
STRONGER OF ANY STORMS THAT DEVELOP. MILD TEMPERATURES CAN BE
EXPECTED TODAY THANKS TO EARLY CLOUD COVER AND THE RAINFALL EARLY
THIS MORNING.
JORDAN
LONG TERM...
ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM GIVEN THE RATHER BUSY
SHORT TERM. UNSETTLED WEATHER STILL APPEARS IN THE CARDS FOR WEST
TEXAS THROUGH LATE WEEK AS NORTHWESTERLY FLOW ALOFT PREVAILS AND A
FRONTAL BOUNDARY AND RICH MOISTURE /HIGH THETA-E AIR/ LINGERS.
TRICKY PART REMAINS PICKING OUT THE SUBTLE DETAILS INCLUDING THE
TIMING OF ANY SHORTWAVES THAT MAY ENHANCE RAIN CHANCES AND
DETERMINING THE EXACT POSITION OF THE LOW-LEVEL FOCUSES THAT MAY
HELP GUIDE WHERE THE BEST RAIN CHANCES WILL BE DURING ANY PERIOD.
THAT SAID...THERE IS DECENT AGREEMENT THAT A PRONOUNCED SHORTWAVE
TROUGH WILL APPROACH FROM WESTERN KANSAS LATE THURSDAY INTO EARLY
FRIDAY AND THIS MAY PROVIDED AN ENHANCED PERIOD FOR STORM
CHANCES...PERHAPS FAVORING THE EASTERN ZONES. A RENEWED SURGE OF
EASTERLY LOW-LEVEL FLOW MAY FOLLOW WITH THE MOIST UPSLOPE FLOW
JUSTIFYING MAINTAINING AT LEAST LOW POPS FRIDAY AFTERNOON/EVENING.
BY THIS TIME THE UPPER FLOW WILL TURN MERIDIONAL...MAKING IT
DIFFICULT FOR CONVECTION ORIGINATING OVER THE MOUNTAINS OF NM/CO
TO MAKE IT INTO THE SOUTH PLAINS THOUGH. THROUGH THIS LATE WEEK
PERIOD...0-6 KM SHEAR WILL BE DECENT /AROUND 30 KNOTS/ AND IF
SUFFICIENT HEATING/INSTABILITY CAN MATERIALIZE...A FEW OF THE
STORMS COULD BE STRONG OR SEVERE. IN ADDITION...ELEVATED MOISTURE
LEVELS ARGUE FOR A HEAVY RAIN THREAT TOO.
WE SHOULD SEE A DRYING TREND AFTER FRIDAY AS THE UPPER FLOW TURNS
MORE NORTHERLY AND ADVECTS IN DRIER AIR ALOFT...THOUGH THE LOW-LEVEL
THETA-E RIDGE MAY PERSIST NEARBY AND COULD KEEP A FEW SHOWER CHANCES
IN THE PICTURE IF THE ECMWF IS CORRECT. THE FLOW WILL FURTHER VEER
TO NORTHEASTERLY EARLY NEXT WEEK WITH DRY CONDITIONS LIKELY TO
CONTINUE. TEMPERATURES SHOULD REMAIN NEAR OR SLIGHTLY BELOW AVERAGE
THROUGH MUCH OF THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 82 61 86 62 87 / 40 40 30 30 20
TULIA 81 62 85 63 85 / 30 40 30 40 20
PLAINVIEW 80 63 87 65 88 / 30 40 30 40 20
LEVELLAND 81 64 88 65 92 / 30 40 30 30 20
LUBBOCK 82 65 88 67 90 / 30 40 30 30 20
DENVER CITY 83 66 89 67 94 / 40 30 30 30 20
BROWNFIELD 83 66 90 66 93 / 40 30 30 30 20
CHILDRESS 85 67 89 68 89 / 30 40 30 40 20
SPUR 83 68 90 68 94 / 30 40 30 40 20
ASPERMONT 84 69 89 71 93 / 40 30 30 30 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
333 PM CDT WED AUG 14 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 333 PM CDT WED AUG 14 2013
AT 3 PM...THE SATELLITE LOOP SHOWED A BROKEN DECK OF 7 TO 8K FOOT
CLOUDS ACROSS THE FORECAST AREA. THE RAP SEEMS TO HAVE THE BEST
HANDLE ON THESE CLOUDS AND THEY SHOW THAT THESE CLOUDS WILL
GRADUALLY DISSIPATE THIS EVENING.
FOR LATE TONIGHT AND THURSDAY MORNING...THE BUFKIT SOUNDINGS SHOW
THAT THERE WILL BE A DEEP LAYER /UP TO 775 MB/ OF LIGHT WINDS
ACROSS THE AREA. WHILE THIS WOULD BE FAVORABLE FOR THE DEVELOPMENT
OF VALLEY FOG. THE NAM/WRF...GFS...AND RAP CONTINUE TO SHOW THAT
THE TEMPERATURE/DEW POINT SPREAD WILL REMAIN AT OR ABOVE 1C. IN
ADDITION...THE GFS AND NAM/WRF SUGGEST THAT THERE COULD BE STILL
SOME CLOUDS AROUND THE REGION. AS A RESULT...WENT WITH PATCHY
VALLEY FOG FOR THE MISSISSIPPI RIVER AND ITS TRIBUTARIES...AND
AREAS OF FOG IN THE WISCONSIN RIVER VALLEY.
ON THURSDAY...THE MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH
WILL MOVE SOUTHEAST ACROSS SOUTHERN AND WESTERN IOWA. WEAK 925 AND
850 MB MOISTURE TRANSPORT NORTHEAST OF THIS SYSTEM WILL AID IN THE
DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND SOUTHWEST
WISCONSIN. WITH ML CAPES LESS THAN 400 J/KG AND VERY WEAK 0-3 KM
AND 0-6 KM...NONE OF THESE THUNDERSTORMS ARE EXPECTED TO BECOME
SEVERE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 333 PM CDT WED AUG 14 2013
ON FRIDAY...THE 925 MB AND 850 MB WEAK MOISTURE TRANSPORT AND 700
TO 600 MB FRONTOGENESIS REMAINS SOUTHWEST OF THE FORECAST AREA.
IN ADDITION...THERE IS VERY LITTLE SURFACE MOISTURE CONVERGENCE
ACROSS THE AREA. WITH THE MESO MODELS IN AGREEMENT WITH THE GEM
AND ECMWF THAT THE AREA WILL REMAIN DRY...REMOVED THE
PRECIPITATION CHANCES FOR THIS TIME PERIOD.
ON BOTH THURSDAY AND FRIDAY NIGHTS...BOTH THE GFS AND NAM/WRF
SOUNDINGS SHOW A DEEP LAYER /UP TO AT LEAST 800 MB/ OF LIGHT
WINDS. THIS WOULD BE VERY FAVORABLE FOR THE DEVELOPMENT OF VALLEY
FOG. HOWEVER THEY ALSO HINT THAT THERE MAY BE SOME CLOUDS AROUND
THE REGION. ANOTHER FACTOR THAT MAY BE A LIMITING FACTOR IS THE
AMOUNT OF MOISTURE IN THE BOUNDARY LAYER. THE NAM/WRF HAS MUCH
MORE MOISTURE THAN THE GFS. DUE TO THIS UNCERTAINTY...JUST
INTRODUCED PATCHY TO AREAS OF VALLEY FOG ON BOTH NIGHTS.
FROM MONDAY THROUGH WEDNESDAY...THE MODELS ARE CONTINUING TO
STRUGGLE WITH THE 500 MB UPPER AIR PATTERN. THE GFS AND GEM ARE
SHOWING THAT THE UPPER LEVEL RIDGE REMAINS LONGER TO THE WEST THAN
THE ECMWF. AS A RESULT...THE GFS AND GEM ARE FASTER AT MOVING THE
COLD FRONT SOUTHEAST INTO THE FORECAST AREA. MEANWHILE THE ECMWF
HAS THE FRONT REMAINING WELL NORTHWEST OF THE FORECAST AREA. SINCE
THE MODELS HAVE BEEN TRENDING SLOWER DURING THIS TIME PERIOD...THE
CONSENSUS OF OUR OFFICE AND THE SURROUNDING WFOS TO KEEP MOST OF
THE FORECAST AREA DRY DURING THIS TIME FRAME.
&&
.AVIATION...THROUGH 18Z THURSDAY
1227 PM CDT WED AUG 14 2013
HIGH PRESSURE CENTERED OVER EASTERN IOWA AND SOUTHERN WISCONSIN WILL
CONTINUE TO PROVIDE VFR CONDITIONS AT BOTH TAF SITES THROUGH MUCH OF
THE TAF PERIOD. LATEST VISIBLE SATELLITE SHOWS DAYTIME ALTO-CUMULUS
DEVELOPING OVER EASTERN MINNESOTA AND WESTERN WISCONSIN. LATEST
METARS INDICATE CEILING HEIGHTS AT OR ABOVE 7000 FEET OVER THIS
AREA. LATEST DETERMINISTIC MODELS SUGGEST THE POSSIBILITY OF SOME
CLOUDS OVER THE AREA TONIGHT. THIS WILL HAVE AN IMPACT ON ANY
RIVER VALLEY FOG FORMING AND AFFECTING THE TAF SITE LSE. AT THIS
TIME...WILL LEAVE ANY MENTION OF FOG REDUCING VISIBILITY AT LSE
DUE TO SOME CLOUDS INHIBITING FOG FORMATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ