Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/01/12
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
220 PM PDT MON JUL 30 2012
.SYNOPSIS...
MONSOON MOISTURE HAS MOVED OVER MOST OF SOUTHWEST CALIFORNIA. THERE
IS A THREAT OF THUNDERSTORMS AND RAINSHOWERS THROUGH WEDNESDAY. THE
CHANCE OF SHOWERS WILL BE WANING DURING THE LATTER HALF OF THE WEEK.
ALONG THE IMMEDIATE COAST AND OVER THE COASTAL WATERS...SOME LATE
NIGHT AND EARLY MORNING LOW CLOUDS AND FOG ARE STILL POSSIBLE.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.EQUIPMENT OUTAGES KNOWN AND PLANNED...
EDWARDS AFB WSR-88D...ETR TUESDAY JULY 31
SAN DIEGO/MIRAMAR WSR-88D...PLANNED OUTAGE TUESDAY 0800-1100 PDT.
&&
.SHORT TERM...
REMAINDER THIS EVENING...
RECENT SATELLITE/RADAR IMAGERY LOOPS INDICATE THE LOW TO MID LEVEL
CIRCULATION OVER IMPERIAL COUNTY STARTING TO LIFT NORTHWARD. WILL
STAY WITH FLASH FLOOD WATCH FOR REMAINDER OF EVENING. RAINFALL
REPORTS/RATES SO FAR ARE IMPRESSIVE FOR REGION...BUT ALSO TYPICAL
FOR PULSE TYPE STORMS IN TROPICAL AIR MASS.THE SURFACE OBS ACROSS
INLAND EMPIRE AND THE HRRR MODEL SHOW ELSINORE CONVERGENCE SETTING
UP ABOUT THIS TIME...2 PM AND CONTINUING THROUGH AT LEAST 6 PM.
STRONG LOW LEVEL MOISTURE ADVECTION HAS BEEN TAKING PLACE THROUGH
THE BANNING PASS WITH DEWPOINTS IN THE 70S AND EAST WINDS 15-25 MPH.
EXPANDED THE COVERAGE AREA FOR TSTMS/SHWRS THIS EVENING TO INCLUDE
MOST OF THE RIVERSIDE COUNTY PORTION OF THE INLAND EMPIRE. OTHERWISE
FORECAST MORE OR LESS UNCHANGED SINCE THE LATE MORNING UPDATE.
TONIGHT THROUGH WEDNESDAY...FROM PREVIOUS DISCUSSION
THE PROXIMITY OF THE LOW/MID LEVEL CIRCULATION WHETHER IT DOES SHIFT
BACK OVER SE CALIFORNIA OR REMAINS BUMPED UP AGAINST THE MOUNTAINS
OF SW CALIFORNIA...THE UPPER LEVEL LOW RETROGRADING BACK OVER SE
CALIFORNIA PER GFS AND EARLIER RUNS OF ECMWF MODEL...AND THE
RESIDUAL MONSOON MOISTURE OVER THE AREA...ALL POINT TO A MOIST AND
CONDITIONALLY UNSTABLE ENVIRONMENT CONTINUING OVER THE EASTERN HALF
OF THE FORECAST AREA. MAY NEED TO CONSIDER ADDITIONAL FLASH FLOOD
WATCHES FOR TUESDAY AND PERHAPS WEDNESDAY.
&&
.LONG TERM...
THURSDAY THROUGH NEXT MONDAY AUGUST 6...
THE SOUTHERN PORTION OF THE EASTERLY WAVE THAT BROUGHT THE MONSOON
MOISTURE TO THE REGION IS CURRENTLY CENTERED ALONG 123W AND SOUTH OF
28N. IT MAKES A LONG CLOCKWISE LOOP AND COMES BACK TO THE OFF THE
CENTRAL CALIFORNIA COAST BY SATURDAY...AND THEN MOVES SLOWLY
NORTHEAST AND INLAND AS A NEGATIVE TILT TROUGH. FOR SOUTHERN
CALIFORNIA THIS WILL BE A DRYING SYNOPTIC PATTERN WITH HIGH PRESSURE
REBUILDING OVER THE AREA. THIS IS SORT OF REFLECTED IN THE CURRENT
FORECASTS.
&&
.AVIATION...
302000Z...COAST/VALLEYS...VFR CONDS WILL PREVAIL THIS AFTN AND
EVENING...WITH INCREASING MID AND HIGH LEVEL CLOUDS THROUGHOUT THE
DAY. STRATUS...WITH BASES AROUND 1000 FT MSL AND TOPS TO 1800 FT
MSL...WILL DEVELOP OVER THE COAST BTWN 08-10Z TONIGHT...AND PUSH
AROUND 10 SM INLAND BY MID TUE MORNING. CONFIDENCE IN STRATUS
DEVELOPMENT OVER KSAN AND KCRQ IS MODERATE...WHILE DEVELOPMENT OVER
KSNA IS LOW. STRATUS WILL CLEAR TOWARDS THE COAST BTWN 16-17Z TUE
MORNING.
MTNS/DESERTS...ISOLATED TO SCATTERED SHOWERS AND TSTMS WILL CONTINUE
TO DEVELOP THIS AFTN AND EVENING. BASES WILL BE AROUND 5000 FT MSL
WITH TOPS TO 35000 FT MSL. LOCALLY GUSTY SFC WINDS AND SMALL HAIL
ARE POSSIBLE WITH THESE STORMS. MOST TSTMS WILL DISSIPATE IN THE
EVENING. HOWEVER...AN ISOLATED TSTM OVERNIGHT IS POSSIBLE.
&&
.FIRE WEATHER...
MONSOON MOISTURE STREAMING THROUGH EAST TO WEST ALIGNED PASSES...AND
INTO INLAND EMPIRE. CABAZON HAS DEWPOINTS IN THE MID 70S WITH EAST
WINDS GUSTING 25 MPH. OTHER RAWS LOCATED NEAR THE SUMMITS AND
PASSES OF RIVERSIDE AND SAN DIEGO COUNTY ARE SHOWING SIMILAR
NUMBERS. ONLY A FEW PLACES ALONG THE MID COASTAL SLOPES IN SAN DIEGO
COUNTY STILL HAVE HUMIDITY BELOW 45 PERCENT...CAPABLE OF SUPPORTING
FIRE SPREADS FROM LIGHTNING STARTS...BUT FURTHER NORTH ACROSS SW SAN
BERNARDINO COUNTY...THERE IS STILL A SLIGHT RISK OF DRY LIGHTNING
STARTS OVER WESTERN HALF OF FIRE WEATHER ZONES CAZ255-CAZ260...SAN
SAN GABRIEL MOUNTAINS AND SAN BERNARDINO MOUNTAINS WEST OF LAKE
ARROWHEAD...VICTOR VALLEY...APPLE VALLEY...LUCERNE VALLEY.
ELSEWHERE...WETTING RAINS WITH AMOUNTS 0.10 TO 0.50 INCHES IN LESS
THAN AN HOUR ARE OCCURRING WITH THE THUNDERSTORMS. MAIN THREAT HERE
WILL BE FLASH FLOODING UNTIL THIS EVENING.
&&
.HYDROLOGY...FROM PREVIOUS DISCUSSION...
THE SATELLITE PRECIPITATION ESTIMATE BRANCH HAS RAINFALL RATES
AROUND 1.5 INCHES ACROSS MOST OF FORECAST AREA. UPSTREAM SOUNDING
TAKEN AT YUMA THIS MORNING SHOWED PRECIPITABLE WATER VALUES OF 2.2
INCHES. GENERAL CONSENSUS OF REGIONAL AND GLOBAL MODELS...
ECMWF/GFS40/NAM12 IS THAT THE HEAVIEST PRECIPITABLE WATER WILL MOVE
BACK TOWARDS THE EAST AND AWAY FROM FORECAST AREA AFTER 4PM. FLASH
FLOOD WATCH CONTINUES UNTIL 2200 PDT.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...UPDATED
CA...FLASH FLOOD WATCH UNTIL 10 PM PDT THIS EVENING FOR THE
COACHELLA VALLEY...RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO
COUNTY DESERTS...SAN DIEGO COUNTY MOUNTAINS.
PZ...NONE.
&&
$$
PUBLIC/FIRE WEATHER...BALFOUR
SHORT TERM WARNINGS...MOEDE
AVIATION/MARINE...JJT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
323 PM MDT MON JUL 30 2012
.SHORT TERM...
(TONIGHT AND TUESDAY)
...MORE INTENSE THUNDERSTORMS TODAY BRINGING THREAT OF HEAVY RAIN TO
PORTIONS OF SOUTH CENTRAL AND SOUTHEAST COLORADO...
UPPER HIGH TO THE SOUTH CONTINUES TO NUDGE THE MAIN TAP OF THE
MONSOON PLUME FARTHER WEST AND NORTH...HOWEVER...YESTERDAY`S FRONT
HAS COMPENSATED SOME WITH AN INCREASE IN LOW LEVEL MOISTURE. THIS
HAS RESULTED IN HIGHER CAPES TODAY ACROSS THE SOUTHEAST
MTS/PLAINS...AND STORMS ON RADAR HAVE DEFINITELY BEEN STRONGER.
CAPE VALUES OFF SPC MESONET SHOWING VALUES SHOWING AROUND 1000-2000
J/KG...THOUGH WITH A LITTLE MIXING...THEY MAY DROP BACK TO AROUND
1000-1500 J/KG. DEEP LAYER SHEARS ARE RUNNING AROUND 20-30KTS...SO
SHOULD NOT LOOKING AT A WIDESPREAD SEVERE RISK...BUT CERTAINLY SOME
STORMS COULD PULSE UP AND PRODUCE HAIL TO AROUND 1 INCH IN
DIAMETER...ESPECIALLY OVER/NEAR THE HIGHER TERRAIN. HRRR BRINGS SEVERAL WAVES
OF THUNDERSTORMS OFF THE SOUTHEAST MTS...PARTICULARLY ACROSS THE
PIKES PEAK REGION WITH THUNDERSTORMS SPREADING OFF INTO THE
SOUTHEAST PLAINS DURING THE EVENING. STORM MOTIONS OFF RADAR HAVE
BEEN TO THE EAST NORTHEAST AROUND 10-15 MPH...HOWEVER WITH CONTINUAL
REGENERATION...IF STORMS TRACK OVER THE SAME LOCATION...LOCALLY
HEAVY RAINFALL WITH THE POTENTIAL FOR FLASH FLOODING WILL BE A
CONCERN...ESPECIALLY FOR THE WALDO CANYON BURN SCAR. ONE STORM HAS ALREADY
COME FAIRLY CLOSE...THOUGH JUST MISSED TO THE SOUTH. HRRR SHOWS
ANOTHER LINE OF THUNDERSTORMS MOVING OFF THE PIKES PEAK REGION AND
POTENTIAL AFFECTING THE BURN SCAR AROUND 22-23Z. GIVEN THAT STORMS
ARE STRONGER TODAY...AND CAPABLE OF HIGHER RAINFALL RATES (UP TO 1.5
INCH PER HOUR)...FLOODING ON THE WALDO CANYON BURN SCAR IS A GREATER
CONCERN. HOWEVER...STORMS WILL STILL BE HIT OR MISS...SO CLOSE
MONITORING OF THE BURN SCAR WILL CONTINUE.
FOR TONIGHT...MODELS IN GENERAL AGREEMENT SPREADING THUNDERSTORMS
EASTWARD ACROSS THE PLAINS THROUGH THE EVENING BEFORE DIMINISHING
TOWARDS MORNING. TUESDAY LOOKS LIKE A SIMILAR EVENT TO TODAY...WITH
LOW LEVEL MOISTURE STILL IN PLACE...BUT MAIN MONSOON PLUME SHIFTED
FARTHER WEST AND NORTH. MAIN TRACK OF ANY SHORTWAVES AROUND THE
PERIPHERY OF THE UPPER RIDGE MAY BE FARTHER NORTH AS WELL...BUT WITH
CONVECTIVE HEATING...MODELS BREAK OUT ANOTHER ROUND OF SCATTERED
THUNDERSTORMS ACROSS THE MOUNTAINS AREAS...WITH GREATEST COVERAGE
ACROSS THE SOUTHEAST MTS. CAPES WILL PROBABLY END UP BEING SIMILAR
TODAY...SO SMALL HAIL AND HEAVY RAINFALL WILL BE THE PRIMARY
THREATS. FLASH FLOODING ON THE WALDO CANYON BURN SCAR WILL BE A
CONCERN ONCE AGAIN.
.LONG TERM...
(TUESDAY NIGHT THROUGH NEXT MONDAY)
TEMPERATURES AND POPS ARE THE PRIMARY METEOROLOGICAL ISSUES DURING
THE LONGER TERM. RECENT COMPUTER MODELS SUGGEST THAT UPPER HIGH
CENTERED OVER THE TEXAS PANHANDLE AT 00Z WEDNESDAY ATTEMPTS TO SLOWLY
SHIFT INTO CENTRAL OKLAHOMA BY 12Z SATURDAY BEFORE PUSHING BACK
INTO THE TEXAS PANHANDLE REGION BY NEXT MONDAY.
FAVORABLE ATMOSPHERIC MOISTURE/HIGH PRECIPITABLE WATER VALUES/MONSOONAL
PLUME ROTATING AROUND THE UPPER HIGH WILL CONTINUE TO IMPACT THE
FORECAST DISTRICT AT TIMES THROUGH THE LONGER TERM. IN
ADDITION...INCREASING SHORT-WAVE ACTIVITY AS WELL AS SEVERAL
NORTHERLY SURGES ARE PROJECTED TO IMPACT THE FORECAST DISTRICT AT
TIMES FROM TUESDAY NIGHT INTO AT LEAST THE UPCOMING WEEKEND.
AS DISCUSSED DURING PREVIOUS DISCUSSIONS...ISOLATED TO SCATTERED
PRIMARILY AFTERNOON AND EVENING THUNDERSTORMS(SOME CONTAINING
LOCALLY HEAVY RAIN AND HAIL) ARE ANTICIPATED OVER MANY SECTIONS OF
THE FORECAST DISTRICT AT TIMES DURING THE LONGER TERM.
AS ALWAYS...PLEASE REMEMBER THAT THE STRONGER STORMS DURING THE
LONGER TERM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND
FLASH FLOODING POTENTIAL(ESPECIALLY OVER BURN SCAR REGIONS SUCH AS
THE WALDO CANYON BURN SCAR). WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY.
FINALLY...MAXIMUM AND MINIMUM TEMPERATURES DURING THE LONGER TERM
SHOULD CONTINUE TO RUN AT TO ABOVE EARLY AUGUST CLIMATOLOGICAL
AVERAGES IN COMBINATION WITH GENERALLY LOW-GRADE GRADIENT WINDS.
&&
.AVIATION...
TSRA WILL BE MOST LIKELY TO IMPACT THE COS TAF SITE THIS
EVENING...WITH HEAVY RAIN...AND ERRATIC GUSTY WINDS UP TO 45 KTS THE
PRIMARY THREAT. SOME SMALL HAIL WILL ALSO BE POSSIBLE. LESS OF A
CHANCE FOR -TSRA TO AFFECT THE KPUB AND KALS TAF SITE...SO WILL
MAINTAIN VCTS IN TAFS THERE. WINDS SHOULD SHIFT OUT OF THE NORTH TO
NORTHWEST WITH CONVECTIVE OUTFLOWS SPREADING OFF THE MOUNTAINS
DURING THE 23-00Z TIME FRAME FOR KCOS AND KPUB. WINDS AND
THUNDERSTORMS SHOULD DIMINISH THROUGH THE EVENING. ANOTHER ROUND OF
THUNDERSTORMS WILL BE POSSIBLE AGAIN ON TUESDAY...WITH KCOS UNDER
THE GREATEST RISK FOR -TSRA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1135 PM MDT SUN JUL 29 2012
.UPDATE...
UPDATED TO INCREASE WINDS THROUGH AROUND 09Z TONIGHT. NORTH FLOW
CONTINUES TO BE ENHANCED BY AN MCV OVER NORTHEAST COLORADO AND
OUTFLOW WINDS FROM THUNDERSTORMS EARLIER. GUSTS TO 40 KTS WILL
CONTINUE OVER THE NEXT COUPLE OF HOURS AND DECREASE THROUGH 09Z.
LATEST RADAR TRENDS HAVE INDICATED ISOLATED THUNDERSTORMS NEAR
TRINIDAD AND WEST OF PUEBLO...SO ADDED THE MENTION OF ISOLATED
THUNDERSTORMS FOR THESE AREAS THROUGH THE NEXT HOUR OR SO. MOZLEY
&&
.PREV DISCUSSION... /ISSUED 1106 PM MDT SUN JUL 29 2012/
AVIATION...
ISOLATED THUNDERSTORMS CONTINUE OVER THE MOUNTAINS OVERNIGHT BUT
SHOULD NOT IMPACT THE TERMINALS. NORTH WINDS HAVE BEEN GUSTY AT
KCOS AND KPUB...WITH GUSTS APPROACHING 35-40 KTS. THESE WINDS WILL
CONTINUE THROUGH 09Z TONIGHT WITH LIGHTER WINDS THROUGH THE
MORNING. THUNDERSTORMS ARE FORECAST TO REDEVELOP OVER THE
MOUNTAINS AND SPREAD EAST ACROSS THE TERMINALS DURING THE LATE
AFTERNOON HOURS. GUSTY OUTFLOW WINDS WILL BE THE MAIN THREAT.
88
PREV DISCUSSION... /ISSUED 927 PM MDT SUN JUL 29 2012/
UPDATE...
UPDATED TO REMOVE POPS FOR THE PLAINS FOR THE REST OF TONIGHT. AN
OUTFLOW BOUNDARY HAS SHIFTED SOUTH ACROSS THE PLAINS WHICH HAS
HELPED STABILIZE THE PLAINS. ISOLATED SHOWER AND THUNDERSTORM
ACTIVITY WILL CONTINUE OVER THE MOUNTAIN REGIONS...ESPECIALLY THE
CONTINENTAL DIVIDE AREA. NO OTHER CHANGES AT THIS TIME. 88
PREV DISCUSSION... /ISSUED 355 PM MDT SUN JUL 29 2012/
SHORT TERM...
(TONIGHT AND MONDAY)
WATER VAPOR LOOPS TODAY CONTINUE TO SHOW DRY AIR PUNCHING IN UNDER
THE RIDGE ACROSS NM/SRN CO. LATEST AMSU SSM/I PRECIP WATER SAT PICS
ALSO SHOWING VALUES DROPPING OFF TO THE SOUTH...BUT STILL AN AXIS OF
HIGH PRECIP WATERS EXTENDING ACROSS NW CO. A COUPLE SHORTWAVES
EVIDENT IN WV PICS ACROSS UT/NW CO. MAIN FORCING FROM THESE MAY END
UP STAYING JUST TO THE NORTH OF THE FORECAST...BUT STILL ENOUGH
MOISTURE PRESENT WITHIN MONSOON PLUME ALOFT FOR SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS. GREATEST
COVERAGE WILL BE ACROSS CHAFFEE AND LAKE COUNTIES...AND POSSIBLY
TELLER...THOUGH EACH SUCCESSIVE HRRR RUN SEEMS TO SHIFT
AXIS OF HIGHER QPF TO THE NORTH ACROSS PARK COUNTY. WITH PRECIP
WATERS STILL AVERAGING AROUND OR SLIGHTLY BETTER THAN 100 PERCENT OF
NORMAL ACROSS THE SOUTHEAST MTS/ADJACENT PLAINS...LOCALLY HEAVY RAIN
WILL STILL BE A THREAT...PARTICULARLY FOR THE WALDO CANYON BURN SCAR
WHERE SOILS ARE SUSCEPTIBLE TO FLASH FLOODING WITH EVEN MINOR
AMOUNTS OF RAINFALL...ESPECIALLY WITH THE LIGHT RAIN THAT FELL
ACROSS THE REGION YESTERDAY. THE LOOSE SOILS OF THE CHALK CLIFFS IN
CHAFFEE COUNTY WOULD BE PRONE TO FLASH FLOODING TODAY AS WELL.
CONVECTION WHICH FIRES OFF TO THE NORTH AND MOVES ACROSS THE NE
PLAINS WILL SEND AN INITIAL CONVECTIVE OUTFLOW BOUNDARY THROUGH THE
NRN I-25 CORRIDOR...WITH A WIND SHIFT FROM THE WEST TO NORTHWEST
DURING THE EVENING PRIOR TO THE MAIN FRONT DROPPING SOUTHWARD
THROUGH THE PLAINS AFTER 03Z. LATEST NAM12 ADVECTS SOME LOWER 50S
DEW POINTS BEHIND THE FRONT INTO SE CO BY MON MORNING...THEN SHIFTS
WINDS WEAKLY FROM THE EAST AND MIXES OUT LOW LEVEL MOISTURE AGAIN BY
AFTERNOON...WITH DEW POINTS FALLING OFF INTO THE LOWER TO MID 40S BY
21Z. DRY AIR ALOFT WILL STILL BE LINGERING OVER SOUTHERN
AREAS...WITH MONSOON PLUME WITH ITS WEAK EMBEDDED IMPULSES EXTENDING
ACROSS UT THROUGH NRN AND CENTRAL CO. THUS GREATEST THREAT FOR
WIDESPREAD THUNDERSTORMS/HEAVY RAIN WILL BE ACROSS NORTHERN PORTIONS
OF THE FORECAST AREA. QUITE A BIT OF DISCREPANCIES IN THE MODEL
QPFS BETWEEN THE DRIER NAM AND THE WET GFS. GFS KEEPS DEW POINTS
ACROSS THE SE PLAINS IN THE 50S THROUGH THE AFTERNOON WITH STRONGER
EASTERLY UPSLOPE FLOW...RESULTING IN GREATER QPF FOR THE SE MTS.
ECMWF SIDES WITH THE DRIER NAM12...AND SREF IS SOMEWHERE IN
BETWEEN...THOUGH ITS QPF IS GENERALLY UNDER .25 ON AN AREAL AVERAGE
BASIS. LCLS STILL LOOK A LITTLE TOO HIGH TO JUSTIFY A FLASH FLOOD
WATCH AT THIS POINT...SO PLAN TO HOLD OFF. LATER SHIFTS CAN GET A
LOOK AT THE HIGH RES MODEL RUNS TONIGHT AND DECIDE IF ONE IS
JUSTIFIED. A LOT WILL DEPEND ON HOW FAR NORTH THE DRY AIR ALOFT
PROGRESSES OVERNIGHT. HOWEVER...THERE COULD BE A HEIGHTENED CONCERN
FOR FLASH FLOODING ON THE WALDO BURN SCAR TOMORROW VS THE PAST FEW
DAYS...AS SFC DEW POINTS SHOULD REMAIN A LITTLE HIGHER.
OTHERWISE...TEMPERATURES SHOULD BE SLIGHTLY COOLER ACROSS THE PLAINS
BEHIND THE FRONT...THOUGH STILL APPROACHING 100 NEAR THE CO/KS
BORDER. MTN AREAS WILL SEE HIGHS SIMILAR TO A COUPLE DEGREES
WARMER. -KT
LONG TERM...
(MONDAY NIGHT THROUGH SUNDAY)
LONGER TERM METEOROLOGICAL ISSUES CONTINUE TO BE TEMPERATURES AND
POPS. 12Z/28TH GFS40 INDICATES THAT UPPER HIGH CENTERED OVER
NORTHEASTERN NEW MEXICO AT 00Z TUESDAY HOVERS OVER NEW MEXICO INTO
NEXT WEEKEND WHILE THE 12Z/28TH ECMWF SUGGESTS THAT HEALTHY UPPER
HIGH LOCATED OVER NORTHEASTERN NEW MEXICO AT 00Z TUESDAY SHIFTS
INTO NORTH TEXAS BY 06Z SATURDAY. IN ADDITION...THE 06Z/28TH DGEX
SUGGESTS THAT THE UPPER HIGH WILL BE OVER MISSOURI BY NEXT SUNDAY.
AT THE SURFACE...NORTHERLY SURGES IMPACTING PRIMARILY EASTERN
PORTIONS OF THE FORECAST DISTRICT ARE ANTICIPATED THURSDAY
MORNING...WITH A STRONGER NORTHERLY SURGE EXPECTED SATURDAY
MORNING.
THE COMBINATION OF RELATIVELY PERSISTENT DEEPER ATMOSPHERIC
MOISTURE/HIGHER PRECIPITABLE WATER VALUES IN COMBINATION WITH
THE DAILY HEATING CYCLE...THE AFORE-MENTIONED NORTHERLY SURGES
AND INCREASING UPPER ENERGY(ESPECIALLY AFTER TUESDAY) WILL ALLOW
ISOLATED TO SCATTERED PRIMARILY AFTERNOON AND EVENING
THUNDERSTORMS(SOME CONTAINING LOCALLY HEAVY RAIN AND HAIL) TO BE
NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT INTO NEXT
WEEKEND.
BLEND OF LATEST COMPUTER SIMULATIONS SUGGEST THAT INCREASING
PROBABILITIES OF THUNDERSTORMS WILL BE POSSIBLE OVER PORTIONS OF
THE I-25 CORRIDOR/EASTERN COLORADO PLAINS AS THE WEEK PROGRESSES
AND INTO NEXT WEEKEND.
AS ALWAYS...PLEASE REMEMBER THAT THE STRONGER STORMS DURING THE
LONGER TERM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND FLASH
FLOODING POTENTIAL(ESPECIALLY OVER BURN SCAR REGIONS SUCH AS THE
WALDO CANYON BURN SCAR). WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY.
MAXIMUM AND MINIMUM TEMPERATURES FROM TUESDAY NIGHT INTO NEXT
SUNDAY ARE STILL EXPECTED TO RUN A CATEGORY OR TWO ABOVE LATE
JULY/EARLY AUGUST CLIMATOLOGICAL AVERAGES.
AVIATION...
VCTS WILL BE POSSIBLE AT TAF SITES THROUGH 02-03Z. GUSTY ERRATIC
WINDS UP TO 35 KTS WILL BE POSSIBLE NEAR -TSRA POSSIBLY AFFECTING
THE KCOS AND KPUB SITES. VFR CIGS/VIS IN LIGHT RAIN WILL ALSO BE
POSSIBLE SHOULD STORMS BE LUCKY ENOUGH TO HIT THE TERMINAL. AT THIS
POINT THREAT LOOKS FAIRLY LOW...AND WILL MAINTAIN VCTS. CONVECTION
OVER THE MOUNTAINS SHOULD SHIFT WINDS FROM THE NORTH TO NORTHWEST AT
BOTH KCOS AND KPUB AROUND 00Z WITH GUSTS IN THE 15-25 KT RANGE.
FRONT WILL DROP THROUGH THE PLAINS AFTER 03Z...WHICH SHOULD KEEP
WINDS FROM THE NORTH AT AROUND 10-15 KTS FOR BOTH KCOS AND KPUB
THROUGH 09Z. MEANWHILE...THUNDERSTORM COVERAGE SHOULD DECREASE
AFTER SUNSET...THOUGH ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE
OVER AND NEAR THE MOUNTAINS THROUGH AT LEAST 06Z. ON MONDAY...WINDS
WILL SWING AROUND FROM THE EAST TO SOUTHEAST ACROSS THE PLAINS
DURING THE AFTERNOON WITH A SLIGHTLY BETTER CHANCE FOR -TSRA AT THE
KCOS TAF SITE DURING THE AFTERNOON. WINDS WILL REMAIN LIGHT AT KALS.
-KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
88/40
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1106 PM MDT SUN JUL 29 2012
.AVIATION...
ISOLATED THUNDERSTORMS CONTINUE OVER THE MOUNTAINS OVERNIGHT BUT
SHOULD NOT IMPACT THE TERMINALS. NORTH WINDS HAVE BEEN GUSTY AT
KCOS AND KPUB...WITH GUSTS APPROACHING 35-40 KTS. THESE WINDS WILL
CONTINUE THROUGH 09Z TONIGHT WITH LIGHTER WINDS THROUGH THE
MORNING. THUNDERSTORMS ARE FORECAST TO REDEVELOP OVER THE
MOUNTAINS AND SPREAD EAST ACROSS THE TERMINALS DURING THE LATE
AFTERNOON HOURS. GUSTY OUTFLOW WINDS WILL BE THE MAIN THREAT.
MOZLEY
&&
.PREV DISCUSSION... /ISSUED 927 PM MDT SUN JUL 29 2012/
UPDATE...
UPDATED TO REMOVE POPS FOR THE PLAINS FOR THE REST OF TONIGHT. AN
OUTFLOW BOUNDARY HAS SHIFTED SOUTH ACROSS THE PLAINS WHICH HAS
HELPED STABILIZE THE PLAINS. ISOLATED SHOWER AND THUNDERSTORM
ACTIVITY WILL CONTINUE OVER THE MOUNTAIN REGIONS...ESPECIALLY THE
CONTINENTAL DIVIDE AREA. NO OTHER CHANGES AT THIS TIME. 88
PREV DISCUSSION... /ISSUED 355 PM MDT SUN JUL 29 2012/
SHORT TERM...
(TONIGHT AND MONDAY)
WATER VAPOR LOOPS TODAY CONTINUE TO SHOW DRY AIR PUNCHING IN UNDER
THE RIDGE ACROSS NM/SRN CO. LATEST AMSU SSM/I PRECIP WATER SAT PICS
ALSO SHOWING VALUES DROPPING OFF TO THE SOUTH...BUT STILL AN AXIS OF
HIGH PRECIP WATERS EXTENDING ACROSS NW CO. A COUPLE SHORTWAVES
EVIDENT IN WV PICS ACROSS UT/NW CO. MAIN FORCING FROM THESE MAY END
UP STAYING JUST TO THE NORTH OF THE FORECAST...BUT STILL ENOUGH
MOISTURE PRESENT WITHIN MONSOON PLUME ALOFT FOR SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS. GREATEST
COVERAGE WILL BE ACROSS CHAFFEE AND LAKE COUNTIES...AND POSSIBLY
TELLER...THOUGH EACH SUCCESSIVE HRRR RUN SEEMS TO SHIFT
AXIS OF HIGHER QPF TO THE NORTH ACROSS PARK COUNTY. WITH PRECIP
WATERS STILL AVERAGING AROUND OR SLIGHTLY BETTER THAN 100 PERCENT OF
NORMAL ACROSS THE SOUTHEAST MTS/ADJACENT PLAINS...LOCALLY HEAVY RAIN
WILL STILL BE A THREAT...PARTICULARLY FOR THE WALDO CANYON BURN SCAR
WHERE SOILS ARE SUSCEPTIBLE TO FLASH FLOODING WITH EVEN MINOR
AMOUNTS OF RAINFALL...ESPECIALLY WITH THE LIGHT RAIN THAT FELL
ACROSS THE REGION YESTERDAY. THE LOOSE SOILS OF THE CHALK CLIFFS IN
CHAFFEE COUNTY WOULD BE PRONE TO FLASH FLOODING TODAY AS WELL.
CONVECTION WHICH FIRES OFF TO THE NORTH AND MOVES ACROSS THE NE
PLAINS WILL SEND AN INITIAL CONVECTIVE OUTFLOW BOUNDARY THROUGH THE
NRN I-25 CORRIDOR...WITH A WIND SHIFT FROM THE WEST TO NORTHWEST
DURING THE EVENING PRIOR TO THE MAIN FRONT DROPPING SOUTHWARD
THROUGH THE PLAINS AFTER 03Z. LATEST NAM12 ADVECTS SOME LOWER 50S
DEW POINTS BEHIND THE FRONT INTO SE CO BY MON MORNING...THEN SHIFTS
WINDS WEAKLY FROM THE EAST AND MIXES OUT LOW LEVEL MOISTURE AGAIN BY
AFTERNOON...WITH DEW POINTS FALLING OFF INTO THE LOWER TO MID 40S BY
21Z. DRY AIR ALOFT WILL STILL BE LINGERING OVER SOUTHERN
AREAS...WITH MONSOON PLUME WITH ITS WEAK EMBEDDED IMPULSES EXTENDING
ACROSS UT THROUGH NRN AND CENTRAL CO. THUS GREATEST THREAT FOR
WIDESPREAD THUNDERSTORMS/HEAVY RAIN WILL BE ACROSS NORTHERN PORTIONS
OF THE FORECAST AREA. QUITE A BIT OF DISCREPANCIES IN THE MODEL
QPFS BETWEEN THE DRIER NAM AND THE WET GFS. GFS KEEPS DEW POINTS
ACROSS THE SE PLAINS IN THE 50S THROUGH THE AFTERNOON WITH STRONGER
EASTERLY UPSLOPE FLOW...RESULTING IN GREATER QPF FOR THE SE MTS.
ECMWF SIDES WITH THE DRIER NAM12...AND SREF IS SOMEWHERE IN
BETWEEN...THOUGH ITS QPF IS GENERALLY UNDER .25 ON AN AREAL AVERAGE
BASIS. LCLS STILL LOOK A LITTLE TOO HIGH TO JUSTIFY A FLASH FLOOD
WATCH AT THIS POINT...SO PLAN TO HOLD OFF. LATER SHIFTS CAN GET A
LOOK AT THE HIGH RES MODEL RUNS TONIGHT AND DECIDE IF ONE IS
JUSTIFIED. A LOT WILL DEPEND ON HOW FAR NORTH THE DRY AIR ALOFT
PROGRESSES OVERNIGHT. HOWEVER...THERE COULD BE A HEIGHTENED CONCERN
FOR FLASH FLOODING ON THE WALDO BURN SCAR TOMORROW VS THE PAST FEW
DAYS...AS SFC DEW POINTS SHOULD REMAIN A LITTLE HIGHER.
OTHERWISE...TEMPERATURES SHOULD BE SLIGHTLY COOLER ACROSS THE PLAINS
BEHIND THE FRONT...THOUGH STILL APPROACHING 100 NEAR THE CO/KS
BORDER. MTN AREAS WILL SEE HIGHS SIMILAR TO A COUPLE DEGREES
WARMER. -KT
LONG TERM...
(MONDAY NIGHT THROUGH SUNDAY)
LONGER TERM METEOROLOGICAL ISSUES CONTINUE TO BE TEMPERATURES AND
POPS. 12Z/28TH GFS40 INDICATES THAT UPPER HIGH CENTERED OVER
NORTHEASTERN NEW MEXICO AT 00Z TUESDAY HOVERS OVER NEW MEXICO INTO
NEXT WEEKEND WHILE THE 12Z/28TH ECMWF SUGGESTS THAT HEALTHY UPPER
HIGH LOCATED OVER NORTHEASTERN NEW MEXICO AT 00Z TUESDAY SHIFTS
INTO NORTH TEXAS BY 06Z SATURDAY. IN ADDITION...THE 06Z/28TH DGEX
SUGGESTS THAT THE UPPER HIGH WILL BE OVER MISSOURI BY NEXT SUNDAY.
AT THE SURFACE...NORTHERLY SURGES IMPACTING PRIMARILY EASTERN
PORTIONS OF THE FORECAST DISTRICT ARE ANTICIPATED THURSDAY
MORNING...WITH A STRONGER NORTHERLY SURGE EXPECTED SATURDAY
MORNING.
THE COMBINATION OF RELATIVELY PERSISTENT DEEPER ATMOSPHERIC
MOISTURE/HIGHER PRECIPITABLE WATER VALUES IN COMBINATION WITH
THE DAILY HEATING CYCLE...THE AFORE-MENTIONED NORTHERLY SURGES
AND INCREASING UPPER ENERGY(ESPECIALLY AFTER TUESDAY) WILL ALLOW
ISOLATED TO SCATTERED PRIMARILY AFTERNOON AND EVENING
THUNDERSTORMS(SOME CONTAINING LOCALLY HEAVY RAIN AND HAIL) TO BE
NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT INTO NEXT
WEEKEND.
BLEND OF LATEST COMPUTER SIMULATIONS SUGGEST THAT INCREASING
PROBABILITIES OF THUNDERSTORMS WILL BE POSSIBLE OVER PORTIONS OF
THE I-25 CORRIDOR/EASTERN COLORADO PLAINS AS THE WEEK PROGRESSES
AND INTO NEXT WEEKEND.
AS ALWAYS...PLEASE REMEMBER THAT THE STRONGER STORMS DURING THE
LONGER TERM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND FLASH
FLOODING POTENTIAL(ESPECIALLY OVER BURN SCAR REGIONS SUCH AS THE
WALDO CANYON BURN SCAR). WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY.
MAXIMUM AND MINIMUM TEMPERATURES FROM TUESDAY NIGHT INTO NEXT
SUNDAY ARE STILL EXPECTED TO RUN A CATEGORY OR TWO ABOVE LATE
JULY/EARLY AUGUST CLIMATOLOGICAL AVERAGES.
AVIATION...
VCTS WILL BE POSSIBLE AT TAF SITES THROUGH 02-03Z. GUSTY ERRATIC
WINDS UP TO 35 KTS WILL BE POSSIBLE NEAR -TSRA POSSIBLY AFFECTING
THE KCOS AND KPUB SITES. VFR CIGS/VIS IN LIGHT RAIN WILL ALSO BE
POSSIBLE SHOULD STORMS BE LUCKY ENOUGH TO HIT THE TERMINAL. AT THIS
POINT THREAT LOOKS FAIRLY LOW...AND WILL MAINTAIN VCTS. CONVECTION
OVER THE MOUNTAINS SHOULD SHIFT WINDS FROM THE NORTH TO NORTHWEST AT
BOTH KCOS AND KPUB AROUND 00Z WITH GUSTS IN THE 15-25 KT RANGE.
FRONT WILL DROP THROUGH THE PLAINS AFTER 03Z...WHICH SHOULD KEEP
WINDS FROM THE NORTH AT AROUND 10-15 KTS FOR BOTH KCOS AND KPUB
THROUGH 09Z. MEANWHILE...THUNDERSTORM COVERAGE SHOULD DECREASE
AFTER SUNSET...THOUGH ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE
OVER AND NEAR THE MOUNTAINS THROUGH AT LEAST 06Z. ON MONDAY...WINDS
WILL SWING AROUND FROM THE EAST TO SOUTHEAST ACROSS THE PLAINS
DURING THE AFTERNOON WITH A SLIGHTLY BETTER CHANCE FOR -TSRA AT THE
KCOS TAF SITE DURING THE AFTERNOON. WINDS WILL REMAIN LIGHT AT KALS.
-KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
88/40
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1004 PM EDT TUE JUL 31 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM EAST OF NEW JERSEY WILL MOVE THROUGH THE NEW
ENGLAND COASTAL WATERS TONIGHT. A WEAK COLD FRONT MOVING THROUGH THE
GREAT LAKES WILL DISSIPATE BEFORE REACHING THE FORECAST AREA ON
WEDNESDAY. A SECOND LOW PRESSURE WILL DEVELOP OVER THE SOUTHEAST
STATES WEDNESDAY AND TRACK WELL OFF THE NEW JERSEY COAST ON
THURSDAY. A BERMUDA HIGH PRESSURE SYSTEM WILL THEN BUILD INTO THE
WESTERN ATLANTIC FOR THE REST OF THE WEEK. IT WILL STOP THE
PROGRESSION OF ANOTHER COLD FRONT AS IT TRIES TO EXIT THE SAINT
LAWRENCE VALLEY ON SATURDAY. A THIRD AND SLIGHTLY STRONGER COLD
FRONT IS FORECAST TO MOVE THROUGH THE GREAT LAKES ON SUNDAY AND
SLOWLY MOVE THROUGH OUR FORECAST AREA ON MONDAY BEFORE STALLING
SOUTH OF THE REGION ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LINE OF THUNDERSTORMS APPROACHING FROM SOUTH CENTRAL
PENNSYLVANIA IS FALLING APART...AS IT OUTRUNS ITS INSTABILITY
SOURCE. A FEW GUSTS TO 40 MPH ARE POSSIBLE WITH THE STORMS AS THEY
REACH THE LEHIGH VALLEY AND POSSIBLE SOUTHEAST PENNSYLVANIA.
HOWEVER...THE OVERALL WEAKENING TREND SHOULD CONTINUE AS THE LOW
LEVEL STABILIZE AHEAD OF THE AREA OF SHOWERS AND THUNDERSTORMS.
THE LATEST HRRR TRIES TO KEEP THIS LINE INTACT AS IT APPROACHES
PHILADELPHIA AFTER 0300 UTC. THIS IS LOOK MORE LIKELY NOW BASED ON
THE TREND OF THE AREAL MOVEMENT. THE UPTICK IN ACTIVITY WAS
INCLUDED IN THE MOST RECENT FORECAST UPDATE.
A BRIEF LULL IS EXPECTED BEFORE MORE SHOWERS APPROACH FROM THE
WEST DURING THE LATE OVERNIGHT HOURS AS A FRONTAL BOUNDARY PUSHES
EAST. TEMPERATURES ARE EXPECTED TO BOTTOM OUT IN THE LOW 60S NORTH
AND IN THE UPPER 60S SOUTH. WITH DEW POINT TEMPERATURES WITHIN A
DEGREE OR TWO OF THESE LOWS...SOME PATCHY FOG IS POSSIBLE TOWARD
MORNING. LIGHT AND VARIABLE WINDS DURING THE OVERNIGHT HOURS ARE
EXPECTED TO BECOME SOUTHERLY TOWARD MORNING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
SHOWERS...AND POSSIBLY A THUNDERSTORM OR TWO...ARE EXPECTED TO
APPROACH OUR WESTERN COUNTIES DURING THE LATE OVERNIGHT HOURS...THEN
OVERSPREAD THE REST OF OUR FORECAST AREA AS THE DAY WEARS ON. GIVEN
THE AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...SOME HEAVY
DOWNPOURS ARE POSSIBLE ON WEDNESDAY. THESE DOWNPOURS ARE EXPECTED TO
BE ISOLATED...BUT WHERE THEY DO OCCUR...THEY COULD PRODUCE A
SIGNIFICANT AMOUNT OF RAIN IN A SHORT PERIOD OF TIME. TEMPERATURES
ARE EXPECTED TO MAX OUT IN THE MID 80S MOST PLACES GIVEN A GOOD
CLOUD COVER AND RAIN CONDITIONS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
NO BIG CHANGES TO THE LONG TERM VS YESTERDAY AS THE TROFINESS IN
THE EASTERN CONUS WILL BE REPLACED BY A MORE ZONAL FLOW. THIS WILL
BRING THE RETURN OF A HOTTER AND MORE HUMID AIR MASS INTO MONDAY
WITH THE POSSIBILITY OF SOME DRYING AND LESSER POSSIBILITY OF
"COOLING" ON TUESDAY.
WHILE THE GFS INITIALIZATION LOOKED BETTER AT 500MB, ITS PERFECTLY
SPHERICAL GRID SCALE PRODUCED LOW PRESSURE SYSTEMS IN THE SHORT TERM
HAS MADE US DISCARD IT FOR THE LONG TERM. THE PASSING OF A STRONGER
LOW PRESSURE SYSTEM FASTER ON THURSDAY IS ILLOGICAL. STRONGER
SHOULD BE SLOWER AND STRONGER SOLUTIONS SHOULD NOT OCCUR AS TROFS
ARE SHEARING. OUR SOLUTION IN THE NEARER END OF THE SHORT TERM
WAS TOWARD A WRF-NMMB AND ECMWF COMPROMISE AND AN ECMWF-HPC
COMPROMISE IN THE REST OF THE LONG TERM. THE GFS HAS NOT BEEN
ALONE WITH THESE LOWS COMING OFF THE SE COAST, DP/DTING SOME
CANADIAN AND WRF-NMMB SOLUTIONS HAS SHOWN LOW NUMBER ONE WAS
OVERFORECAST IN STRENGTH ALSO.
THE IMPULSE ASSOCIATED WITH THE DISSIPATING COLD FRONT WILL CONTINUE
TO MOVE THROUGH OUR CWA ON WEDNESDAY EVENING AND WE MAINTAIN
RELATIVELY HIGH POPS FOR THE START OF THE OVERNIGHT AND MAINLY IN
THE OFFSHORE WATERS LATE. STAT GUIDANCE LOOKS REASONABLE AND WAS
FOLLOWED.
ON THURSDAY THE FASTER AND STRONGER GFS AND STRONGER CAN GGEM WERE
DISCOUNTED AS LIKELY BEING AFFECTED BY GRIDSCALE FEEDBACK EFFECTS.
OUR SOLUTION IS CLOSEST TO THE WRF-NMMB TRACK AND STRENGTH. THIS
WOULD ALLOW ENOUGH SEPARATION BETWEEN SYSTEMS FOR SCATTERED
THUNDERSTORMS TO DEVELOP DURING THE DAY. HIGHEST POPS WERE PLACED IN
THE DELAWARE VALLEY WHERE CONSENSUS HIEST FCST CAPES EXIST. BECAUSE
OF THE STRONG SYSTEM, GFS MOS MAX TEMPS ARE LOWER ON THU. WE ARE
OPTING FOR A WARMER AIR MASS AND ARE CLOSER TO NAM MOS.
PRECIPITATION SHOULD BE DIURNALLY DRIVEN AND AS WE APPROACH THE 72HR
ITS HARD TO ACCEPT THAT THE WRF-NMMB IS GOING TO VERIFY ITS TIMING
AND PLACEMENT WITH THE OVERNIGHT SHORTWAVE NORTH. SO POPS WERE
DROPPED QUICKLY THURSDAY EVENING. MIN TEMPS WERE A STAT GUIDANCE
COMPROMISE.
FRIDAY MIGHT STILL BE THE "DRY POPLESS DAY". BUT FOR NOW, MODEL
FORECAST SOUNDINGS DO NOT SHOW A STRONG ENOUGH CAP. POPS WERE PLACED
NORTHWEST WHERE HIEST FCST INSTABILITY WAS SHOWN BY THE MAJORITY OF
MODELS. HERE WE DO NOT THINK THAT THE WRF-NMMB SOLUTION OF
BRINGING THE AXIS OF INSTABILITY CAN BUCK THE ZONAL FLOW AND GET
INTO THE SOUTHERN PART OF OUR CWA. BY THIS TIME PERIOD ITS LIKELY
SHOWING ITS HOT BIAS AND OUR MAX TEMPS ARE CLOSER TO GFS MOS. BTW
THE 00Z MEX MOS GUIDANCE WAS AMONG THE HOTTEST OF ITS ENSEMBLE
MEMBERS. FCST DEW POINTS KEEP AFTERNOON HEAT INDICES SHORT OF HEAT
HEADLINE CRITERIA IN URBAN AREAS.
NO BIG CHANGES TO WEEKEND THINKING WITH SUNDAY BEING THE MORE
LIKELIER DAY TO HAVE TSTMS AROUND. NEXT ATTEMPTED COLD FRONT SHOULD
STOP SHORT OF OUR CWA ON SATURDAY, BUT IMPULSES FROM IT SHOULD
TRIGGER AT LEAST SOME WIDELY SCATTERED TSTMS. A BETTER CHANCE ON
SUNDAY AS THE FRONT APPROACHES AND IN LIKELIHOOD A LEE SIDE TROF
FORMS. MAX TEMPS ARE KEPT AS STATUS QUO VS DROPPING THEM ON THE
WEEKEND BASED ON FCST 850MB AND 925MB TEMPS AND NOT COUNTING ON
EXCESS CLOUDINESS TO KEEP TEMPS DOWN. WITH HIGHER DEW POINTS, WE
MIGHT MAKE HEAT HEADLINE CRITERIA ON THE WEEKEND IN THE MORE
URBANIZED LOCALES AND WE WILL CONTINUE MENTION IN THE HWO.
NOT AS SURE FOR MONDAY,
THE FRONT IS EXPECTED TO TRUNDLE THROUGH OUR FORECAST AREA ON
MONDAY. THE MODEL TIMING IS NOT THAT DIFFERENT AND THE 00Z ECMWF
ENSEMBLE MEAN WAS CLOSE TO THE MODEL`S DETERMINISTIC SOLUTION. THUS
NOT AS CONFIDENT ABOUT THE 90S OR HEAT HEADLINES ON MONDAY AS THERE
SHOULD BE MORE CLOUDS AROUND AND HAVE PLACED HIEST POPS EAST BASED
ON THE ENSEMBLE FRONTAL POSN AT 12Z MON.
WHILE THIS FRONT MAY BE `STRONGER", ITS ONLY BECAUSE THE PREVIOUS
TWO WERE LEFT IN THE METEOROLOGICAL GUTTER. SO ON TUESDAY ITS BEST
IMPACT MAY BE TO LOWER DEW POINTS SOMEWHAT WITH NOT A BIG DROP IN
TEMPS FORECAST. WE WILL START TUESDAY AS A DRY DAY AND SEE WHAT
TOMORROW BRINGS.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS EVENING. A LINE OF SHOWERS AND
THUNDERSTORMS MOVING ACROSS SOUTH CENTRAL PENNSYLVANIA COULD TRACK
CLOSE ENOUGH TO KRDG AND KABE BY 0130 UTC TO RESULT IN LOCAL MVFR
CONDITIONS. IT WILL BE A PRESS TIME DECISION WAS TO WHETHER MVFR
CONDITIONS NEED TO BE INCLUDED...AND THE TREND OF THE LINE WILL BE
THE PRIMARY DECISION MAKER.
NEAR TERM MODEL SUGGEST THAT THE SHOWERS COULD AFFECT THE KPHL METRO
AIRPORTS AND KILG THROUGH 0400 UTC. IT IS POSSIBLE THAT THE KPHL
METRO AIRPORTS COULD SEE A BRIEF PERIOD OF MVFR CONDITIONS WITH
THE SHRINKING AREA OF SHOWERS AND THUNDERSTORMS. THE TERMINAL
FORECASTS THERE WILL BE UPDATED AS THE AREA GETS CLOSER.
AFTER THIS...THE FORECAST SHOULD BE DRY. THE EAST SOUTHEAST FLOW
COULD RESULT IN A PERIOD OF MVFR CEILINGS AT KRDG...KABE AND KTTN.
FURTHER SOUTH AND EAST...THE CEILING FORECAST WAS MAINLY VFR...WITH
PATCHY FOG AT KMIV.
FOR WEDNESDAY...MAINLY VFR CONDITIONS ARE EXPECTED. AN ONGOING LINE
OF SHOWERS AND THUNDERSTORMS COULD BEGIN TO AFFECT KRDG AND KABE AS
EARLY AS 1400 UTC...AND THIS IS INCLUDED AS A VCSH REMARK AT THESE
LOCATIONS. ELSEWHERE...THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
WAS PUSHED BACK UNTIL 1700 UTC...AND INDICATED WITH A PROB30 REMARK.
WHILE THUNDERSTORMS COULD PRODUCE LOCAL MVFR/IFR CONDITIONS...IT IS
STILL TO EARLY TO INCLUDE THIS IN THE FORECAST. THE THREAT FOR
SHOWERS AND THUNDERSTORMS SHOULD DIMINISH AFTER 0100 UTC THURSDAY.
OUTLOOK...
WEDNESDAY NIGHT...PRIMARILY VFR, EXCEPT LOCALLY IFR IN SCATTERED
HEAVY SHOWERS AND STRONG THUNDERSTORMS. ALSO LOCALLY MVFR TO IFR
IN FOG LATE WED NIGHT.
THURSDAY THROUGH FRIDAY NIGHT...VFR, ISOLATED MVFR CONDITIONS IN
EARLY MORNING FOG AND MORE ISOLATED (VS WEDNESDAY) SHOWERS AND
THUNDERSTORMS.
SATURDAY...PRIMARILY VFR. ISOLATED AFTN/EVENING TSTM. SOME
EARLY MORNING FOG OUTLYING AIRPORTS.
SUNDAY...PRIMARILY VFR. SCATTERED AFTN/EVENING TSTM SHOULD HAVE
MORE OF A MVFR AND OPERATIONAL IMPACT. SOME EARLY MORNING FOG
OUTLYING AIRPORTS.
&&
.MARINE...
THE FORECAST WAS UPDATED TO BEEF UP WINDS OVER THE DELAWARE BAY.
BOTH BRND1 AND SJSN4 ARE GUSTING TO NEAR 20 KNOTS. THE INCREASE IN
WIND SPEED APPEARS TO BE DUE TO THE WIND DIRECTION (FUNNELING ON
THE DAY) AND THE DIURNAL WIND MAXIMUM (WHICH SHOULD START TO BACK
OFF SOON). WINDS SHOULD DROP OFF FAIRLY QUICKLY LATER THIS EVENING.
A BRIEF LULL IS EXPECTED OVER THE FORECAST WATERS LATER TONIGHT
AS LOW PRESSURE OFF THE COAST MOVES NORTHEAST. A GENERAL EASTERLY
FLOW WILL SHIFT TO A MORE SOUTHERLY FLOW LATE TONIGHT AND CONTINUE
THROUGH WEDNESDAY. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A
ADVANCING FRONT WILL MOVE IN FROM THE WEST WEDNESDAY AFTERNOON AND
CONTINUE INTO WEDNESDAY NIGHT. SOME OF THESE THUNDERSTORMS COULD
PRODUCE LOCALLY HAZARDOUS MARINE CONDITIONS...BUT RIGHT NOW SUB-
SCA CONDITIONS ARE EXPECTED ON THE LARGE SCALE.
OUTLOOK...
AS PER PMDHMD AND OPC MIMATN DISCUSSION, WE ARE NOT GOING TO BE
FOLLOWING THE GFS SOLUTION. THUS WINDS AND SEAS WITH THE NEXT
OFFSHORE LOW ARE EXPECTED TO REMAIN BELOW SCA CRITERIA IN OUR
COASTAL WATERS UNTIL THE LOW PASSES TO OUR EAST AROUND THURSDAY.
BEYOND THAT, A GENERAL SOUTHERLY FLOW IS EXPECTED TO PERSIST INTO
SUNDAY. ITS POSSIBLE BY SUNDAY OR BEYOND DETERMINISTIC FORECAST
MONDAY, THE GRADIENT OR PERSISTENCE OF THE SOUTHERLY FLOW MIGHT BE
ENOUGH FOR SMALL CRAFT ADVISORY CRITERIA TO BE MET. IT MAY BE MORE
FOR SEAS THAN WINDS. REGARDLESS CONFIDENCE ABOUT REMAINING BELOW
SMALL CRAFT ADVISORY CRITERIA LOWERS AS THE WEEKEND PROGRESSES.
&&
.HYDROLOGY...
HEAVY DOWNPOURS ASSOCIATED WITH THUNDERSTORMS...ESPECIALLY WEDNESDAY
AFTERNOON...COULD PRODUCE RAPID RUNOFF IN SOME AREAS. THIS SCENARIO
BRINGS WITH IT THE THREAT OF HIGHLY LOCALIZED FLOODING...ESPECIALLY
IN URBAN SETTINGS. RIGHT NOW THIS THREAT DOESN`T APPEAR TO BE
WIDESPREAD ENOUGH TO WARRANT A FLASH FLOOD WATCH...BUT GIVEN THE
AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...CAN`T RULE OUT ONE
OR TWO ISOLATED PROBLEMS.
&&
.TIDES/COASTAL FLOODING...
A COASTAL FLOOD ADVISORY WAS ISSUED FOR THE UPPER DELAWARE BAY.
TIDES WERE RUNNING ABOUT ONE FOOT ABOVE PREDICTED AT REEDY POINT.
THIS TYPE OF DEPARTURE AT HIGH TIDE WILL RESULT IN MINOR TIDAL
FLOODING THERE (HIGH TIDE AT REEDY POINT IS ABOUT 1030 PM).
THE HIGH TIDE CYCLE HAS ENDED ON THE OCEAN FRONT...WHICH ALL TIDE
GAGES REACHING THE MINOR TIDAL FLOODING BENCHMARK. THE BACK BAYS
ARE IN HIGH TIDE NOW...AND THE ADVISORY WAS ALLOWED TO EXPIRE ON
TIME AT 1000 PM.
A REPEAT PERFORMANCE IS POSSIBLE AGAIN WEDNESDAY EVENING DUE TO A
PERSISTENT SOUTHERLY FLOW AND FULL MOON.
&&
.RIP CURRENTS...
MODERATE RISK INTO WEDNESDAY WITH A CONTINUED 2-3 FT SWELL AND
HIGHER THAN NORMAL ASTRONOMICAL TIDES ASSOCIATED WITH THE UPCOMING
FULL MOON.
&&
.CLIMATE...
TOP FIVE WARMEST JULYS ON RECORD IN PARTS OF OUR AREA.
IN TERMS OF 90 DEGREE DAYS FOR THE MONTH OF JULY.
AT PHILADELPHIA 21 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
HIGHER OCCURRED THROUGH THE 29TH. THIS TIES THE RECORD FOR
THE MOST NUMBER OF 90 DEGREES DAYS ALL TIME WITH 1952, 1988, 1995
AND 2011.
AT ALLENTOWN 15 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR HIGHER
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1983, 2010 AND
2011. GREATEST IS 20 DAYS IN 1999, 1966 AND 1955.
AT WILMINGTON 17 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1952. GREATEST
IS 22 DAYS IN 1894.
AT ATLANTIC CITY 14 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
MORE OCCURRED THROUGH THE 29TH. THIS IS FIFTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 2010. GREATEST IS
21 DAYS IN 1983.
AT READING 19 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SECOND ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY. GREATEST IS 20 DAYS
SET IN 2011, 2010, 1999 AND 1955.
IN TERMS OF WARMEST AVERAGE TEMPERATURE RECORDED FOR THE MONTH OF
JULY.
AT PHILADELPHIA THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 81.9. WE ARE PROJECTING 81.7 FOR THE MONTH. THIS IS THE THE
THIRD WARMEST JULY ON RECORD BEHIND 2011 82.4 AND 1994 82.1 AND
EQUALING THE 81.7 IN 2010.
AT WILMINGTON THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 80.4. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2011 AND
1955.
AT ATLANTIC CITY THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 78.7. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2010
AND 2011.
AT ALLENTOWN THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 77.6 AND IS THE SEVENTH WARMEST JULY ON RECORD.
DATA SINCE 6/28 THROUGH 7/30...33 DAYS.
RDG ONLY 2 DAYS BELOW NORMAL
PHL/ABE/GED ONLY 3 DAYS BELOW NORMAL
TTN 5 DAYS BELOW NORMAL
MPO 5 DAYS BELOW NORMAL
ILG 6 DAYS BELOW NORMAL
ACY 10 DAYS BELOW NORMAL
90 OR HIGHER FOR THE SEASON
SO FAR TOTAL
NORMAL THIS YR LAST YR POR
ABE 17 24 21 1922
ACY 22 31
GED 29 40
ILG 27 27
PHL 21 30 33 1874
RDG 30 30
TTN 25 26
MPO 3 4
THE NORMAL AND PERIOD OF RECORD /POR/ IS LISTED FOR ONLY TWO CLIMATE
SITES WHERE THE DATASET IS EASILY AVAILABLE AND COMPLETE.
WITH RESPECT TO OCCURRENCES OF 95 OR GREATER PHL CLIMATOLOGICALLY
AVG`S 4/YR SO FAR THIS YR 12 LAST YRS TOTAL 11.
STATISTICALLY FOR PHL AS EVALUATED BY MARK DELISI...THE NUMBER OF 95
OR WARMER DAYS THIS YEAR IS UNUSUAL.
FOR OUR FORECAST AREA...
PCPN FOR THE MONTH SO FAR NOW GENERALLY WITHIN 75 PCT OF NORMAL.
TEMP FOR THE MONTH SO FAR NOW GENERALLY 2.5 TO 5F ABOVE NORMAL.
&&
.EQUIPMENT...
KDOX RADAR IS EXPECTED TO BE OFFLINE FOR SEVERAL DAYS DUE TO A
PEDESTAL DYNAMIC FAULT. TECHNICIANS ARE WORKING ON THE PROBLEM.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...COASTAL FLOOD ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR NJZ016.
DE...COASTAL FLOOD ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR DEZ001.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GIGI
NEAR TERM...MIKETTA
SHORT TERM...MIKETTA
LONG TERM...GIGI
AVIATION...DRAG/GIGI/HAYES
MARINE...GIGI/HAYES/MIKETTA
HYDROLOGY...MIKETTA
TIDES/COASTAL FLOODING...HAYES/MIKETTA
RIP CURRENTS...HAYES
CLIMATE...CARDINALE/DRAG/GAINES
EQUIPMENT...MIKETTA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
908 PM EDT TUE JUL 31 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM EAST OF NEW JERSEY WILL MOVE THROUGH THE NEW
ENGLAND COASTAL WATERS TONIGHT. A WEAK COLD FRONT MOVING THROUGH THE
GREAT LAKES WILL DISSIPATE BEFORE REACHING THE FORECAST AREA ON
WEDNESDAY. A SECOND LOW PRESSURE WILL DEVELOP OVER THE SOUTHEAST
STATES WEDNESDAY AND TRACK WELL OFF THE NEW JERSEY COAST ON
THURSDAY. A BERMUDA HIGH PRESSURE SYSTEM WILL THEN BUILD INTO THE
WESTERN ATLANTIC FOR THE REST OF THE WEEK. IT WILL STOP THE
PROGRESSION OF ANOTHER COLD FRONT AS IT TRIES TO EXIT THE SAINT
LAWRENCE VALLEY ON SATURDAY. A THIRD AND SLIGHTLY STRONGER COLD
FRONT IS FORECAST TO MOVE THROUGH THE GREAT LAKES ON SUNDAY AND
SLOWLY MOVE THROUGH OUR FORECAST AREA ON MONDAY BEFORE STALLING
SOUTH OF THE REGION ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LINE OF THUNDERSTORMS APPROACHING FROM SOUTH CENTRAL
PENNSYLVANIA IS FALLING APART...AS IT OUTRUNS ITS INSTABILITY
SOURCE. A FEW GUSTS TO 40 MPH ARE POSSIBLE WITH THE STORMS AS THEY
REACH THE LEHIGH VALLEY AND POSSIBLE SOUTHEAST PENNSYLVANIA.
HOWEVER...THE OVERALL WEAKENING TREND SHOULD CONTINUE AS THE LOW
LEVEL STABILIZE AHEAD OF THE AREA OF SHOWERS AND THUNDERSTORMS.
THE LATEST HRRR TRIES TO KEEP THIS LINE INTACT AS IT APPROACHES
PHILADELPHIA AFTER 0300 UTC. THIS IS LOOK MORE LIKELY NOW BASED ON
THE TREND OF THE AREAL MOVEMENT. THE UPTICK IN ACTIVITY WAS
INCLUDED IN THE MOST RECENT FORECAST UPDATE.
A BRIEF LULL IS EXPECTED BEFORE MORE SHOWERS APPROACH FROM THE
WEST DURING THE LATE OVERNIGHT HOURS AS A FRONTAL BOUNDARY PUSHES
EAST. TEMPERATURES ARE EXPECTED TO BOTTOM OUT IN THE LOW 60S NORTH
AND IN THE UPPER 60S SOUTH. WITH DEW POINT TEMPERATURES WITHIN A
DEGREE OR TWO OF THESE LOWS...SOME PATCHY FOG IS POSSIBLE TOWARD
MORNING. LIGHT AND VARIABLE WINDS DURING THE OVERNIGHT HOURS ARE
EXPECTED TO BECOME SOUTHERLY TOWARD MORNING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
SHOWERS...AND POSSIBLY A THUNDERSTORM OR TWO...ARE EXPECTED TO
APPROACH OUR WESTERN COUNTIES DURING THE LATE OVERNIGHT HOURS...THEN
OVERSPREAD THE REST OF OUR FORECAST AREA AS THE DAY WEARS ON. GIVEN
THE AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...SOME HEAVY
DOWNPOURS ARE POSSIBLE ON WEDNESDAY. THESE DOWNPOURS ARE EXPECTED TO
BE ISOLATED...BUT WHERE THEY DO OCCUR...THEY COULD PRODUCE A
SIGNIFICANT AMOUNT OF RAIN IN A SHORT PERIOD OF TIME. TEMPERATURES
ARE EXPECTED TO MAX OUT IN THE MID 80S MOST PLACES GIVEN A GOOD
CLOUD COVER AND RAIN CONDITIONS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
NO BIG CHANGES TO THE LONG TERM VS YESTERDAY AS THE TROFINESS IN
THE EASTERN CONUS WILL BE REPLACED BY A MORE ZONAL FLOW. THIS WILL
BRING THE RETURN OF A HOTTER AND MORE HUMID AIR MASS INTO MONDAY
WITH THE POSSIBILITY OF SOME DRYING AND LESSER POSSIBILITY OF
"COOLING" ON TUESDAY.
WHILE THE GFS INITIALIZATION LOOKED BETTER AT 500MB, ITS PERFECTLY
SPHERICAL GRID SCALE PRODUCED LOW PRESSURE SYSTEMS IN THE SHORT TERM
HAS MADE US DISCARD IT FOR THE LONG TERM. THE PASSING OF A STRONGER
LOW PRESSURE SYSTEM FASTER ON THURSDAY IS ILLOGICAL. STRONGER
SHOULD BE SLOWER AND STRONGER SOLUTIONS SHOULD NOT OCCUR AS TROFS
ARE SHEARING. OUR SOLUTION IN THE NEARER END OF THE SHORT TERM
WAS TOWARD A WRF-NMMB AND ECMWF COMPROMISE AND AN ECMWF-HPC
COMPROMISE IN THE REST OF THE LONG TERM. THE GFS HAS NOT BEEN
ALONE WITH THESE LOWS COMING OFF THE SE COAST, DP/DTING SOME
CANADIAN AND WRF-NMMB SOLUTIONS HAS SHOWN LOW NUMBER ONE WAS
OVERFORECAST IN STRENGTH ALSO.
THE IMPULSE ASSOCIATED WITH THE DISSIPATING COLD FRONT WILL CONTINUE
TO MOVE THROUGH OUR CWA ON WEDNESDAY EVENING AND WE MAINTAIN
RELATIVELY HIGH POPS FOR THE START OF THE OVERNIGHT AND MAINLY IN
THE OFFSHORE WATERS LATE. STAT GUIDANCE LOOKS REASONABLE AND WAS
FOLLOWED.
ON THURSDAY THE FASTER AND STRONGER GFS AND STRONGER CAN GGEM WERE
DISCOUNTED AS LIKELY BEING AFFECTED BY GRIDSCALE FEEDBACK EFFECTS.
OUR SOLUTION IS CLOSEST TO THE WRF-NMMB TRACK AND STRENGTH. THIS
WOULD ALLOW ENOUGH SEPARATION BETWEEN SYSTEMS FOR SCATTERED
THUNDERSTORMS TO DEVELOP DURING THE DAY. HIGHEST POPS WERE PLACED IN
THE DELAWARE VALLEY WHERE CONSENSUS HIEST FCST CAPES EXIST. BECAUSE
OF THE STRONG SYSTEM, GFS MOS MAX TEMPS ARE LOWER ON THU. WE ARE
OPTING FOR A WARMER AIR MASS AND ARE CLOSER TO NAM MOS.
PRECIPITATION SHOULD BE DIURNALLY DRIVEN AND AS WE APPROACH THE 72HR
ITS HARD TO ACCEPT THAT THE WRF-NMMB IS GOING TO VERIFY ITS TIMING
AND PLACEMENT WITH THE OVERNIGHT SHORTWAVE NORTH. SO POPS WERE
DROPPED QUICKLY THURSDAY EVENING. MIN TEMPS WERE A STAT GUIDANCE
COMPROMISE.
FRIDAY MIGHT STILL BE THE "DRY POPLESS DAY". BUT FOR NOW, MODEL
FORECAST SOUNDINGS DO NOT SHOW A STRONG ENOUGH CAP. POPS WERE PLACED
NORTHWEST WHERE HIEST FCST INSTABILITY WAS SHOWN BY THE MAJORITY OF
MODELS. HERE WE DO NOT THINK THAT THE WRF-NMMB SOLUTION OF
BRINGING THE AXIS OF INSTABILITY CAN BUCK THE ZONAL FLOW AND GET
INTO THE SOUTHERN PART OF OUR CWA. BY THIS TIME PERIOD ITS LIKELY
SHOWING ITS HOT BIAS AND OUR MAX TEMPS ARE CLOSER TO GFS MOS. BTW
THE 00Z MEX MOS GUIDANCE WAS AMONG THE HOTTEST OF ITS ENSEMBLE
MEMBERS. FCST DEW POINTS KEEP AFTERNOON HEAT INDICES SHORT OF HEAT
HEADLINE CRITERIA IN URBAN AREAS.
NO BIG CHANGES TO WEEKEND THINKING WITH SUNDAY BEING THE MORE
LIKELIER DAY TO HAVE TSTMS AROUND. NEXT ATTEMPTED COLD FRONT SHOULD
STOP SHORT OF OUR CWA ON SATURDAY, BUT IMPULSES FROM IT SHOULD
TRIGGER AT LEAST SOME WIDELY SCATTERED TSTMS. A BETTER CHANCE ON
SUNDAY AS THE FRONT APPROACHES AND IN LIKELIHOOD A LEE SIDE TROF
FORMS. MAX TEMPS ARE KEPT AS STATUS QUO VS DROPPING THEM ON THE
WEEKEND BASED ON FCST 850MB AND 925MB TEMPS AND NOT COUNTING ON
EXCESS CLOUDINESS TO KEEP TEMPS DOWN. WITH HIGHER DEW POINTS, WE
MIGHT MAKE HEAT HEADLINE CRITERIA ON THE WEEKEND IN THE MORE
URBANIZED LOCALES AND WE WILL CONTINUE MENTION IN THE HWO.
NOT AS SURE FOR MONDAY,
THE FRONT IS EXPECTED TO TRUNDLE THROUGH OUR FORECAST AREA ON
MONDAY. THE MODEL TIMING IS NOT THAT DIFFERENT AND THE 00Z ECMWF
ENSEMBLE MEAN WAS CLOSE TO THE MODEL`S DETERMINISTIC SOLUTION. THUS
NOT AS CONFIDENT ABOUT THE 90S OR HEAT HEADLINES ON MONDAY AS THERE
SHOULD BE MORE CLOUDS AROUND AND HAVE PLACED HIEST POPS EAST BASED
ON THE ENSEMBLE FRONTAL POSN AT 12Z MON.
WHILE THIS FRONT MAY BE `STRONGER", ITS ONLY BECAUSE THE PREVIOUS
TWO WERE LEFT IN THE METEOROLOGICAL GUTTER. SO ON TUESDAY ITS BEST
IMPACT MAY BE TO LOWER DEW POINTS SOMEWHAT WITH NOT A BIG DROP IN
TEMPS FORECAST. WE WILL START TUESDAY AS A DRY DAY AND SEE WHAT
TOMORROW BRINGS.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS EVENING. A LINE OF SHOWERS AND
THUNDERSTORMS MOVING ACROSS SOUTH CENTRAL PENNSYLVANIA COULD TRACK
CLOSE ENOUGH TO KRDG AND KABE BY 0130 UTC TO RESULT IN LOCAL MVFR
CONDITIONS. IT WILL BE A PRESS TIME DECISION WAS TO WHETHER MVFR
CONDITIONS NEED TO BE INCLUDED...AND THE TREND OF THE LINE WILL BE
THE PRIMARY DECISION MAKER.
NEAR TERM MODEL SUGGEST THAT THE SHOWERS COULD AFFECT THE KPHL METRO
AIRPORTS AND KILG THROUGH 0400 UTC. IT IS POSSIBLE THAT THE KPHL
METRO AIRPORTS COULD SEE A BRIEF PERIOD OF MVFR CONDITIONS WITH
THE SHRINKING AREA OF SHOWERS AND THUNDERSTORMS. THE TERMINAL
FORECASTS THERE WILL BE UPDATED AS THE AREA GETS CLOSER.
AFTER THIS...THE FORECAST SHOULD BE DRY. THE EAST SOUTHEAST FLOW
COULD RESULT IN A PERIOD OF MVFR CEILINGS AT KRDG...KABE AND KTTN.
FURTHER SOUTH AND EAST...THE CEILING FORECAST WAS MAINLY VFR...WITH
PATCHY FOG AT KMIV.
FOR WEDNESDAY...MAINLY VFR CONDITIONS ARE EXPECTED. AN ONGOING LINE
OF SHOWERS AND THUNDERSTORMS COULD BEGIN TO AFFECT KRDG AND KABE AS
EARLY AS 1400 UTC...AND THIS IS INCLUDED AS A VCSH REMARK AT THESE
LOCATIONS. ELSEWHERE...THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
WAS PUSHED BACK UNTIL 1700 UTC...AND INDICATED WITH A PROB30 REMARK.
WHILE THUNDERSTORMS COULD PRODUCE LOCAL MVFR/IFR CONDITIONS...IT IS
STILL TO EARLY TO INCLUDE THIS IN THE FORECAST. THE THREAT FOR
SHOWERS AND THUNDERSTORMS SHOULD DIMINISH AFTER 0100 UTC THURSDAY.
OUTLOOK...
WEDNESDAY NIGHT...PRIMARILY VFR, EXCEPT LOCALLY IFR IN SCATTERED
HEAVY SHOWERS AND STRONG THUNDERSTORMS. ALSO LOCALLY MVFR TO IFR
IN FOG LATE WED NIGHT.
THURSDAY THROUGH FRIDAY NIGHT...VFR, ISOLATED MVFR CONDITIONS IN
EARLY MORNING FOG AND MORE ISOLATED (VS WEDNESDAY) SHOWERS AND
THUNDERSTORMS.
SATURDAY...PRIMARILY VFR. ISOLATED AFTN/EVENING TSTM. SOME
EARLY MORNING FOG OUTLYING AIRPORTS.
SUNDAY...PRIMARILY VFR. SCATTERED AFTN/EVENING TSTM SHOULD HAVE
MORE OF A MVFR AND OPERATIONAL IMPACT. SOME EARLY MORNING FOG
OUTLYING AIRPORTS.
&&
.MARINE...
THE FORECAST WAS UPDATED TO BEEF UP WINDS OVER THE DELAWARE BAY.
BOTH BRND1 AND SJSN4 ARE GUSTING TO NEAR 20 KNOTS. THE INCREASE IN
WIND SPEED APPEARS TO BE DUE TO THE WIND DIRECTION (FUNNELING ON
THE DAY) AND THE DIURNAL WIND MAXIMUM (WHICH SHOULD START TO BACK
OFF SOON). WINDS SHOULD DROP OFF FAIRLY QUICKLY LATER THIS EVENING.
A BRIEF LULL IS EXPECTED OVER THE FORECAST WATERS LATER TONIGHT
AS LOW PRESSURE OFF THE COAST MOVES NORTHEAST. A GENERAL EASTERLY
FLOW WILL SHIFT TO A MORE SOUTHERLY FLOW LATE TONIGHT AND CONTINUE
THROUGH WEDNESDAY. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A
ADVANCING FRONT WILL MOVE IN FROM THE WEST WEDNESDAY AFTERNOON AND
CONTINUE INTO WEDNESDAY NIGHT. SOME OF THESE THUNDERSTORMS COULD
PRODUCE LOCALLY HAZARDOUS MARINE CONDITIONS...BUT RIGHT NOW SUB-
SCA CONDITIONS ARE EXPECTED ON THE LARGE SCALE.
OUTLOOK...
AS PER PMDHMD AND OPC MIMATN DISCUSSION, WE ARE NOT GOING TO BE
FOLLOWING THE GFS SOLUTION. THUS WINDS AND SEAS WITH THE NEXT
OFFSHORE LOW ARE EXPECTED TO REMAIN BELOW SCA CRITERIA IN OUR
COASTAL WATERS UNTIL THE LOW PASSES TO OUR EAST AROUND THURSDAY.
BEYOND THAT, A GENERAL SOUTHERLY FLOW IS EXPECTED TO PERSIST INTO
SUNDAY. ITS POSSIBLE BY SUNDAY OR BEYOND DETERMINISTIC FORECAST
MONDAY, THE GRADIENT OR PERSISTENCE OF THE SOUTHERLY FLOW MIGHT BE
ENOUGH FOR SMALL CRAFT ADVISORY CRITERIA TO BE MET. IT MAY BE MORE
FOR SEAS THAN WINDS. REGARDLESS CONFIDENCE ABOUT REMAINING BELOW
SMALL CRAFT ADVISORY CRITERIA LOWERS AS THE WEEKEND PROGRESSES.
&&
.HYDROLOGY...
HEAVY DOWNPOURS ASSOCIATED WITH THUNDERSTORMS...ESPECIALLY WEDNESDAY
AFTERNOON...COULD PRODUCE RAPID RUNOFF IN SOME AREAS. THIS SCENARIO
BRINGS WITH IT THE THREAT OF HIGHLY LOCALIZED FLOODING...ESPECIALLY
IN URBAN SETTINGS. RIGHT NOW THIS THREAT DOESN`T APPEAR TO BE
WIDESPREAD ENOUGH TO WARRANT A FLASH FLOOD WATCH...BUT GIVEN THE
AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...CAN`T RULE OUT ONE
OR TWO ISOLATED PROBLEMS.
&&
.TIDES/COASTAL FLOODING...
A COASTAL FLOOD ADVISORY WAS ISSUED FOR THE UPPER DELAWARE BAY.
TIDES WERE RUNNING ABOUT ONE FOOT ABOVE PREDICTED AT REEDY POINT.
THIS TYPE OF DEPARTURE AT HIGH TIDE WILL RESULT IN MINOR TIDAL
FLOODING THERE (HIGH TIDE AT REEDY POINT IS ABOUT 1030 PM).
THE HIGH TIDE CYCLE HAS ENDED ON THE OCEAN FRONT...WHICH ALL TIDE
GAGES REACHING THE MINOR TIDAL FLOODING BENCHMARK. THE BACK BAYS
ARE IN HIGH TIDE NOW...AND THE ADVISORY THERE SHOULD BE ABLE TO
EXPIRE ON TIME AT 1000 PM.
A REPEAT PERFORMANCE IS POSSIBLE AGAIN WEDNESDAY EVENING DUE TO A
PERSISTENT SOUTHERLY FLOW AND FULL MOON.
&&
.RIP CURRENTS...
MODERATE RISK INTO WEDNESDAY WITH A CONTINUED 2-3 FT SWELL AND
HIGHER THAN NORMAL ASTRONOMICAL TIDES ASSOCIATED WITH THE UPCOMING
FULL MOON.
&&
.CLIMATE...
TOP FIVE WARMEST JULYS ON RECORD IN PARTS OF OUR AREA.
IN TERMS OF 90 DEGREE DAYS FOR THE MONTH OF JULY.
AT PHILADELPHIA 21 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
HIGHER OCCURRED THROUGH THE 29TH. THIS TIES THE RECORD FOR
THE MOST NUMBER OF 90 DEGREES DAYS ALL TIME WITH 1952, 1988, 1995
AND 2011.
AT ALLENTOWN 15 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR HIGHER
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1983, 2010 AND
2011. GREATEST IS 20 DAYS IN 1999, 1966 AND 1955.
AT WILMINGTON 17 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1952. GREATEST
IS 22 DAYS IN 1894.
AT ATLANTIC CITY 14 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
MORE OCCURRED THROUGH THE 29TH. THIS IS FIFTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 2010. GREATEST IS
21 DAYS IN 1983.
AT READING 19 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SECOND ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY. GREATEST IS 20 DAYS
SET IN 2011, 2010, 1999 AND 1955.
IN TERMS OF WARMEST AVERAGE TEMPERATURE RECORDED FOR THE MONTH OF
JULY.
AT PHILADELPHIA THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 81.9. WE ARE PROJECTING 81.7 FOR THE MONTH. THIS IS THE THE
THIRD WARMEST JULY ON RECORD BEHIND 2011 82.4 AND 1994 82.1 AND
EQUALING THE 81.7 IN 2010.
AT WILMINGTON THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 80.4. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2011 AND
1955.
AT ATLANTIC CITY THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 78.7. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2010
AND 2011.
AT ALLENTOWN THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 77.6 AND IS THE SEVENTH WARMEST JULY ON RECORD.
DATA SINCE 6/28 THROUGH 7/30...33 DAYS.
RDG ONLY 2 DAYS BELOW NORMAL
PHL/ABE/GED ONLY 3 DAYS BELOW NORMAL
TTN 5 DAYS BELOW NORMAL
MPO 5 DAYS BELOW NORMAL
ILG 6 DAYS BELOW NORMAL
ACY 10 DAYS BELOW NORMAL
90 OR HIGHER FOR THE SEASON
SO FAR TOTAL
NORMAL THIS YR LAST YR POR
ABE 17 24 21 1922
ACY 22 31
GED 29 40
ILG 27 27
PHL 21 30 33 1874
RDG 30 30
TTN 25 26
MPO 3 4
THE NORMAL AND PERIOD OF RECORD /POR/ IS LISTED FOR ONLY TWO CLIMATE
SITES WHERE THE DATASET IS EASILY AVAILABLE AND COMPLETE.
WITH RESPECT TO OCCURRENCES OF 95 OR GREATER PHL CLIMATOLOGICALLY
AVG`S 4/YR SO FAR THIS YR 12 LAST YRS TOTAL 11.
STATISTICALLY FOR PHL AS EVALUATED BY MARK DELISI...THE NUMBER OF 95
OR WARMER DAYS THIS YEAR IS UNUSUAL.
FOR OUR FORECAST AREA...
PCPN FOR THE MONTH SO FAR NOW GENERALLY WITHIN 75 PCT OF NORMAL.
TEMP FOR THE MONTH SO FAR NOW GENERALLY 2.5 TO 5F ABOVE NORMAL.
&&
.EQUIPMENT...
KDOX RADAR IS EXPECTED TO BE OFFLINE FOR SEVERAL DAYS DUE TO A
PEDESTAL DYNAMIC FAULT. TECHNICIANS ARE WORKING ON THE PROBLEM.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...COASTAL FLOOD ADVISORY UNTIL 10 PM EDT THIS EVENING FOR NJZ013-
014-020>027.
COASTAL FLOOD ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR NJZ016.
DE...COASTAL FLOOD ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
DEZ002>004.
COASTAL FLOOD ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR DEZ001.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GIGI
NEAR TERM...MIKETTA
SHORT TERM...MIKETTA
LONG TERM...GIGI
AVIATION...DRAG/GIGI/HAYES
MARINE...GIGI/HAYES/MIKETTA
HYDROLOGY...MIKETTA
TIDES/COASTAL FLOODING...HAYES/MIKETTA
RIP CURRENTS...HAYES
CLIMATE...CARDINALE/DRAG/GAINES
EQUIPMENT...MIKETTA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
714 PM EDT TUE JUL 31 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM EAST OF NEW JERSEY WILL MOVE THROUGH THE NEW
ENGLAND COASTAL WATERS TONIGHT. A WEAK COLD FRONT MOVING THROUGH THE
GREAT LAKES WILL DISSIPATE BEFORE REACHING THE FORECAST AREA ON
WEDNESDAY. A SECOND LOW PRESSURE WILL DEVELOP OVER THE SOUTHEAST
STATES WEDNESDAY AND TRACK WELL OFF THE NEW JERSEY COAST ON
THURSDAY. A BERMUDA HIGH PRESSURE SYSTEM WILL THEN BUILD INTO THE
WESTERN ATLANTIC FOR THE REST OF THE WEEK. IT WILL STOP THE
PROGRESSION OF ANOTHER COLD FRONT AS IT TRIES TO EXIT THE SAINT
LAWRENCE VALLEY ON SATURDAY. A THIRD AND SLIGHTLY STRONGER COLD
FRONT IS FORECAST TO MOVE THROUGH THE GREAT LAKES ON SUNDAY AND
SLOWLY MOVE THROUGH OUR FORECAST AREA ON MONDAY BEFORE STALLING
SOUTH OF THE REGION ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A LINE OF SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL
PENNSYLVANIA IS THE FOCUS OF THE NEAR TERM. UNLIKE THE PULSE TYPE
ACTIVITY ACROSS NORTHEAST MARYLAND AND DELAWARE LATE THIS AFTERNOON...
THIS ACTIVITY HAS BEEN ON THE UPSWING IN THE PAST 90 MINUTES...AS
IT FORMS ON A SURFACE CONVERGENCE LINE AHEAD OF A MID LEVEL TROUGH.
THE LINE IS MOVING THROUGH THE BEST SURFACE BEST INSTABILITY...AND
WILL SHORTLY APPROACH THE MORE STABLE EAST SOUTHEAST SURFACE FLOW.
THE LATEST HRRR TRIES TO KEEP THIS LINE INTACT AS IT APPROACHES
PHILADELPHIA AFTER 0300 UTC. A GENERAL WEAKENING OF THE ACTIVITY
WOULD BE EXPECTED AS IT OUTRUNS ITS INSTABILITY ABOUT THE TIME OF
THE LOSS OF DAYTIME HEATING. NO ENHANCED WORDING WAS INCLUDED FOR
THE EVENING...BUT THIS COULD CHANGE IF THE TREND OF THE CONVECTION
DOES NOT CHANGES AS IT APPROACHES THE LEHIGH VALLEY.
A BRIEF LULL IS EXPECTED BEFORE MORE SHOWERS APPROACH FROM THE
WEST DURING THE LATE OVERNIGHT HOURS AS A FRONTAL BOUNDARY PUSHES
EAST. TEMPERATURES ARE EXPECTED TO BOTTOM OUT IN THE LOW 60S NORTH
AND IN THE UPPER 60S SOUTH. WITH DEW POINT TEMPERATURES WITHIN A
DEGREE OR TWO OF THESE LOWS...SOME PATCHY FOG IS POSSIBLE TOWARD
MORNING. LIGHT AND VARIABLE WINDS DURING THE OVERNIGHT HOURS ARE
EXPECTED TO BECOME SOUTHERLY TOWARD MORNING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
SHOWERS...AND POSSIBLY A THUNDERSTORM OR TWO...ARE EXPECTED TO
APPROACH OUR WESTERN COUNTIES DURING THE LATE OVERNIGHT HOURS...THEN
OVERSPREAD THE REST OF OUR FORECAST AREA AS THE DAY WEARS ON. GIVEN
THE AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...SOME HEAVY
DOWNPOURS ARE POSSIBLE ON WEDNESDAY. THESE DOWNPOURS ARE EXPECTED TO
BE ISOLATED...BUT WHERE THEY DO OCCUR...THEY COULD PRODUCE A
SIGNIFICANT AMOUNT OF RAIN IN A SHORT PERIOD OF TIME. TEMPERATURES
ARE EXPECTED TO MAX OUT IN THE MID 80S MOST PLACES GIVEN A GOOD
CLOUD COVER AND RAIN CONDITIONS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
NO BIG CHANGES TO THE LONG TERM VS YESTERDAY AS THE TROFINESS IN
THE EASTERN CONUS WILL BE REPLACED BY A MORE ZONAL FLOW. THIS WILL
BRING THE RETURN OF A HOTTER AND MORE HUMID AIR MASS INTO MONDAY
WITH THE POSSIBILITY OF SOME DRYING AND LESSER POSSIBILITY OF
"COOLING" ON TUESDAY.
WHILE THE GFS INITIALIZATION LOOKED BETTER AT 500MB, ITS PERFECTLY
SPHERICAL GRID SCALE PRODUCED LOW PRESSURE SYSTEMS IN THE SHORT TERM
HAS MADE US DISCARD IT FOR THE LONG TERM. THE PASSING OF A STRONGER
LOW PRESSURE SYSTEM FASTER ON THURSDAY IS ILLOGICAL. STRONGER
SHOULD BE SLOWER AND STRONGER SOLUTIONS SHOULD NOT OCCUR AS TROFS
ARE SHEARING. OUR SOLUTION IN THE NEARER END OF THE SHORT TERM
WAS TOWARD A WRF-NMMB AND ECMWF COMPROMISE AND AN ECMWF-HPC
COMPROMISE IN THE REST OF THE LONG TERM. THE GFS HAS NOT BEEN
ALONE WITH THESE LOWS COMING OFF THE SE COAST, DP/DTING SOME
CANADIAN AND WRF-NMMB SOLUTIONS HAS SHOWN LOW NUMBER ONE WAS
OVERFORECAST IN STRENGTH ALSO.
THE IMPULSE ASSOCIATED WITH THE DISSIPATING COLD FRONT WILL CONTINUE
TO MOVE THROUGH OUR CWA ON WEDNESDAY EVENING AND WE MAINTAIN
RELATIVELY HIGH POPS FOR THE START OF THE OVERNIGHT AND MAINLY IN
THE OFFSHORE WATERS LATE. STAT GUIDANCE LOOKS REASONABLE AND WAS
FOLLOWED.
ON THURSDAY THE FASTER AND STRONGER GFS AND STRONGER CAN GGEM WERE
DISCOUNTED AS LIKELY BEING AFFECTED BY GRIDSCALE FEEDBACK EFFECTS.
OUR SOLUTION IS CLOSEST TO THE WRF-NMMB TRACK AND STRENGTH. THIS
WOULD ALLOW ENOUGH SEPARATION BETWEEN SYSTEMS FOR SCATTERED
THUNDERSTORMS TO DEVELOP DURING THE DAY. HIGHEST POPS WERE PLACED IN
THE DELAWARE VALLEY WHERE CONSENSUS HIEST FCST CAPES EXIST. BECAUSE
OF THE STRONG SYSTEM, GFS MOS MAX TEMPS ARE LOWER ON THU. WE ARE
OPTING FOR A WARMER AIR MASS AND ARE CLOSER TO NAM MOS.
PRECIPITATION SHOULD BE DIURNALLY DRIVEN AND AS WE APPROACH THE 72HR
ITS HARD TO ACCEPT THAT THE WRF-NMMB IS GOING TO VERIFY ITS TIMING
AND PLACEMENT WITH THE OVERNIGHT SHORTWAVE NORTH. SO POPS WERE
DROPPED QUICKLY THURSDAY EVENING. MIN TEMPS WERE A STAT GUIDANCE
COMPROMISE.
FRIDAY MIGHT STILL BE THE "DRY POPLESS DAY". BUT FOR NOW, MODEL
FORECAST SOUNDINGS DO NOT SHOW A STRONG ENOUGH CAP. POPS WERE PLACED
NORTHWEST WHERE HIEST FCST INSTABILITY WAS SHOWN BY THE MAJORITY OF
MODELS. HERE WE DO NOT THINK THAT THE WRF-NMMB SOLUTION OF
BRINGING THE AXIS OF INSTABILITY CAN BUCK THE ZONAL FLOW AND GET
INTO THE SOUTHERN PART OF OUR CWA. BY THIS TIME PERIOD ITS LIKELY
SHOWING ITS HOT BIAS AND OUR MAX TEMPS ARE CLOSER TO GFS MOS. BTW
THE 00Z MEX MOS GUIDANCE WAS AMONG THE HOTTEST OF ITS ENSEMBLE
MEMBERS. FCST DEW POINTS KEEP AFTERNOON HEAT INDICES SHORT OF HEAT
HEADLINE CRITERIA IN URBAN AREAS.
NO BIG CHANGES TO WEEKEND THINKING WITH SUNDAY BEING THE MORE
LIKELIER DAY TO HAVE TSTMS AROUND. NEXT ATTEMPTED COLD FRONT SHOULD
STOP SHORT OF OUR CWA ON SATURDAY, BUT IMPULSES FROM IT SHOULD
TRIGGER AT LEAST SOME WIDELY SCATTERED TSTMS. A BETTER CHANCE ON
SUNDAY AS THE FRONT APPROACHES AND IN LIKELIHOOD A LEE SIDE TROF
FORMS. MAX TEMPS ARE KEPT AS STATUS QUO VS DROPPING THEM ON THE
WEEKEND BASED ON FCST 850MB AND 925MB TEMPS AND NOT COUNTING ON
EXCESS CLOUDINESS TO KEEP TEMPS DOWN. WITH HIGHER DEW POINTS, WE
MIGHT MAKE HEAT HEADLINE CRITERIA ON THE WEEKEND IN THE MORE
URBANIZED LOCALES AND WE WILL CONTINUE MENTION IN THE HWO.
NOT AS SURE FOR MONDAY,
THE FRONT IS EXPECTED TO TRUNDLE THROUGH OUR FORECAST AREA ON
MONDAY. THE MODEL TIMING IS NOT THAT DIFFERENT AND THE 00Z ECMWF
ENSEMBLE MEAN WAS CLOSE TO THE MODEL`S DETERMINISTIC SOLUTION. THUS
NOT AS CONFIDENT ABOUT THE 90S OR HEAT HEADLINES ON MONDAY AS THERE
SHOULD BE MORE CLOUDS AROUND AND HAVE PLACED HIEST POPS EAST BASED
ON THE ENSEMBLE FRONTAL POSN AT 12Z MON.
WHILE THIS FRONT MAY BE `STRONGER", ITS ONLY BECAUSE THE PREVIOUS
TWO WERE LEFT IN THE METEOROLOGICAL GUTTER. SO ON TUESDAY ITS BEST
IMPACT MAY BE TO LOWER DEW POINTS SOMEWHAT WITH NOT A BIG DROP IN
TEMPS FORECAST. WE WILL START TUESDAY AS A DRY DAY AND SEE WHAT
TOMORROW BRINGS.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS EVENING. A LINE OF SHOWERS AND
THUNDERSTORMS MOVING ACROSS SOUTH CENTRAL PENNSYLVANIA COULD TRACK
CLOSE ENOUGH TO KRDG AND KABE BY 0130 UTC TO RESULT IN LOCAL MVFR
CONDITIONS. IT WILL BE A PRESS TIME DECISION WAS TO WHETHER MVFR
CONDITIONS NEED TO BE INCLUDED...AND THE TREND OF THE LINE WILL BE
THE PRIMARY DECISION MAKER.
NEAR TERM MODEL SUGGEST THAT THE SHOWERS COULD AFFECT THE KPHL METRO
AIRPORTS AND KILG THROUGH 0400 UTC. THIS SEEMS LESS LIKELY...UNLESS
THE CURRENT LINE SURVIVES THE TRIP. FOR NOW...VFR CONDITIONS WILL BE
FORECAST AT THE ABOVEMENTIONED LOCATIONS THROUGH 0400 UTC.
AFTER THIS...THE FORECAST SHOULD BE DRY. THE EAST SOUTHEAST FLOW
COULD RESULT IN A PERIOD OF MVFR CEILINGS AT KRDG...KABE AND KTTN.
FURTHER SOUTH AND EAST...THE CEILING FORECAST WAS MAINLY VFR...WITH
PATCHY FOG AT KMIV.
FOR WEDNESDAY...MAINLY VFR CONDITIONS ARE EXPECTED. AN ONGOING LINE
OF SHOWERS AND THUNDERSTORMS COULD BEGIN TO AFFECT KRDG AND KABE AS
EARLY AS 1400 UTC...AND THIS IS INCLUDED AS A VCSH REMARK AT THESE
LOCATIONS. ELSEWHERE...THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
WAS PUSHED BACK UNTIL 1700 UTC...AND INDICATED WITH A PROB30 REMARK.
WHILE THUNDERSTORMS COULD PRODUCE LOCAL MVFR/IFR CONDITIONS...IT IS
STILL TO EARLY TO INCLUDE THIS IN THE FORECAST. THE THREAT FOR
SHOWERS AND THUNDERSTORMS SHOULD DIMINISH AFTER 0100 UTC THURSDAY.
OUTLOOK...
WEDNESDAY NIGHT...PRIMARILY VFR, EXCEPT LOCALLY IFR IN SCATTERED
HEAVY SHOWERS AND STRONG THUNDERSTORMS. ALSO LOCALLY MVFR TO IFR
IN FOG LATE WED NIGHT.
THURSDAY THROUGH FRIDAY NIGHT...VFR, ISOLATED MVFR CONDITIONS IN
EARLY MORNING FOG AND MORE ISOLATED (VS WEDNESDAY) SHOWERS AND
THUNDERSTORMS.
SATURDAY...PRIMARILY VFR. ISOLATED AFTN/EVENING TSTM. SOME
EARLY MORNING FOG OUTLYING AIRPORTS.
SUNDAY...PRIMARILY VFR. SCATTERED AFTN/EVENING TSTM SHOULD HAVE
MORE OF A MVFR AND OPERATIONAL IMPACT. SOME EARLY MORNING FOG
OUTLYING AIRPORTS.
&&
.MARINE...
THE FORECAST WAS UPDATED TO BEEF UP WINDS OVER THE DELAWARE BAY.
BOTH BRDN1 AND SJSN4 ARE STARTING TO SHOW WINDS GETTING CLOSE TO
15 KNOTS...AND LWSD1 IS NOT FAR BEHIND. THE INCREASE IN WIND SPEED
APPEARS TO BE DUE TO THE WIND DIRECTION (FUNNELING ON THE DAY) AND
THE DIURNAL WIND MAXIMUM (IN CONJUNCTION WITH THE DIURNAL
PRESSURE MINIMUM). WINDS SHOULD DROP OFF FAIRLY QUICKLY LATER THIS
EVENING.
A BRIEF LULL IS EXPECTED OVER THE FORECAST WATERS TONIGHT AS LOW
PRESSURE OFF THE COAST MOVES NORTHEAST. A GENERAL EASTERLY FLOW WILL
SHIFT TO A MORE SOUTHERLY FLOW LATE TONIGHT AND CONTINUE THROUGH
WEDNESDAY. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A ADVANCING
FRONT WILL MOVE IN FROM THE WEST WEDNESDAY AFTERNOON AND CONTINUE
INTO WEDNESDAY NIGHT. SOME OF THESE THUNDERSTORMS COULD PRODUCE
LOCALLY HAZARDOUS MARINE CONDITIONS...BUT RIGHT NOW SUB-SCA
CONDITIONS ARE EXPECTED ON THE LARGE SCALE.
OUTLOOK...
AS PER PMDHMD AND OPC MIMATN DISCUSSION, WE ARE NOT GOING TO BE
FOLLOWING THE GFS SOLUTION. THUS WINDS AND SEAS WITH THE NEXT
OFFSHORE LOW ARE EXPECTED TO REMAIN BELOW SCA CRITERIA IN OUR
COASTAL WATERS UNTIL THE LOW PASSES TO OUR EAST AROUND THURSDAY.
BEYOND THAT, A GENERAL SOUTHERLY FLOW IS EXPECTED TO PERSIST INTO
SUNDAY. ITS POSSIBLE BY SUNDAY OR BEYOND DETERMINISTIC FORECAST
MONDAY, THE GRADIENT OR PERSISTENCE OF THE SOUTHERLY FLOW MIGHT BE
ENOUGH FOR SMALL CRAFT ADVISORY CRITERIA TO BE MET. IT MAY BE MORE
FOR SEAS THAN WINDS. REGARDLESS CONFIDENCE ABOUT REMAINING BELOW
SMALL CRAFT ADVISORY CRITERIA LOWERS AS THE WEEKEND PROGRESSES.
&&
.HYDROLOGY...
HEAVY DOWNPOURS ASSOCIATED WITH THUNDERSTORMS...ESPECIALLY WEDNESDAY
AFTERNOON...COULD PRODUCE RAPID RUNOFF IN SOME AREAS. THIS SCENARIO
BRINGS WITH IT THE THREAT OF HIGHLY LOCALIZED FLOODING...ESPECIALLY
IN URBAN SETTINGS. RIGHT NOW THIS THREAT DOESN`T APPEAR TO BE
WIDESPREAD ENOUGH TO WARRANT A FLASH FLOOD WATCH...BUT GIVEN THE
AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...CAN`T RULE OUT ONE
OR TWO ISOLATED PROBLEMS.
&&
.TIDES/COASTAL FLOODING...
A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR BOTH THE NJ AND DE
OCEANFRONTS...AND THE LOWER DELAWARE BAY...FOR THIS EVENING/S HIGH
TIDE. PEAK WATER LEVELS SHOULD REACH OR SLIGHTLY EXCEED WHAT WAS
EXPERIENCED AT HIGH TIDE MONDAY EVENING IN THESE LOCATIONS. WHILE ONLY
NUISANCE FLOODING IS EXPECTED...GIVEN THIS IS PEAK VACATION SEASON
DOWN THE SHORE...THOUGHT IT PRUDENT TO ISSUE AN ADVISORY RATHER THAN
JUST A STATEMENT FOR BETTER EXPOSURE. THE TIME BASE OF THIS MINOR
FLOODING SHOULD BE SHY OF ONE HOUR ON EITHER SIDE OF THE TIME OF
HIGH TIDE AT ANY GIVEN LOCATION.
WHILE WATER LEVELS WILL BE RUNNING HIGH IN THE CHESAPEAKE BAY AND
THE UPPER DELAWARE BAY...INCLUDING THE TIDAL SECTIONS OF THE
DELAWARE RIVER...CURRENT GUIDANCE SUGGESTS MINOR FLOOD LEVELS
WON`T BE REACHED.
A REPEAT PERFORMANCE IS POSSIBLE AGAIN WEDNESDAY EVENING DUE TO A
PERSISTENT SOUTHERLY FLOW AND FULL MOON.
&&
.RIP CURRENTS...
MODERATE RISK INTO TONIGHT WITH A CONTINUED 2-3 FT SWELL AND
HIGHER THAN NORMAL ASTRONOMICAL TIDES ASSOCIATED WITH THE UPCOMING
FULL MOON.
&&
.CLIMATE...
TOP FIVE WARMEST JULYS ON RECORD IN PARTS OF OUR AREA.
IN TERMS OF 90 DEGREE DAYS FOR THE MONTH OF JULY.
AT PHILADELPHIA 21 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
HIGHER OCCURRED THROUGH THE 29TH. THIS TIES THE RECORD FOR
THE MOST NUMBER OF 90 DEGREES DAYS ALL TIME WITH 1952, 1988, 1995
AND 2011.
AT ALLENTOWN 15 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR HIGHER
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1983, 2010 AND
2011. GREATEST IS 20 DAYS IN 1999, 1966 AND 1955.
AT WILMINGTON 17 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1952. GREATEST
IS 22 DAYS IN 1894.
AT ATLANTIC CITY 14 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
MORE OCCURRED THROUGH THE 29TH. THIS IS FIFTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 2010. GREATEST IS
21 DAYS IN 1983.
AT READING 19 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SECOND ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY. GREATEST IS 20 DAYS
SET IN 2011, 2010, 1999 AND 1955.
IN TERMS OF WARMEST AVERAGE TEMPERATURE RECORDED FOR THE MONTH OF
JULY.
AT PHILADELPHIA THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 81.9. WE ARE PROJECTING 81.7 FOR THE MONTH. THIS IS THE THE
THIRD WARMEST JULY ON RECORD BEHIND 2011 82.4 AND 1994 82.1 AND
EQUALING THE 81.7 IN 2010.
AT WILMINGTON THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 80.4. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2011 AND
1955.
AT ATLANTIC CITY THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 78.7. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2010
AND 2011.
AT ALLENTOWN THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 77.6 AND IS THE SEVENTH WARMEST JULY ON RECORD.
DATA SINCE 6/28 THROUGH 7/30...33 DAYS.
RDG ONLY 2 DAYS BELOW NORMAL
PHL/ABE/GED ONLY 3 DAYS BELOW NORMAL
TTN 5 DAYS BELOW NORMAL
MPO 5 DAYS BELOW NORMAL
ILG 6 DAYS BELOW NORMAL
ACY 10 DAYS BELOW NORMAL
90 OR HIGHER FOR THE SEASON
SO FAR TOTAL
NORMAL THIS YR LAST YR POR
ABE 17 24 21 1922
ACY 22 31
GED 29 40
ILG 27 27
PHL 21 30 33 1874
RDG 30 30
TTN 25 26
MPO 3 4
THE NORMAL AND PERIOD OF RECORD /POR/ IS LISTED FOR ONLY TWO CLIMATE
SITES WHERE THE DATASET IS EASILY AVAILABLE AND COMPLETE.
WITH RESPECT TO OCCURRENCES OF 95 OR GREATER PHL CLIMATOLOGICALLY
AVG`S 4/YR SO FAR THIS YR 12 LAST YRS TOTAL 11.
STATISTICALLY FOR PHL AS EVALUATED BY MARK DELISI...THE NUMBER OF 95
OR WARMER DAYS THIS YEAR IS UNUSUAL.
FOR OUR FORECAST AREA...
PCPN FOR THE MONTH SO FAR NOW GENERALLY WITHIN 75 PCT OF NORMAL.
TEMP FOR THE MONTH SO FAR NOW GENERALLY 2.5 TO 5F ABOVE NORMAL.
&&
.EQUIPMENT...
KDOX RADAR IS EXPECTED TO BE OFFLINE FOR SEVERAL DAYS DUE TO A
PEDESTAL DYNAMIC FAULT. TECHNICIANS ARE WORKING ON THE PROBLEM.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...COASTAL FLOOD ADVISORY UNTIL 10 PM EDT THIS EVENING FOR NJZ013-
014-020>027.
DE...COASTAL FLOOD ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
DEZ002>004.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GIGI
NEAR TERM...MIKETTA
SHORT TERM...MIKETTA
LONG TERM...GIGI
AVIATION...DRAG/GIGI/HAYES
MARINE...GIGI/HAYES/MIKETTA
HYDROLOGY...MIKETTA
TIDES/COASTAL FLOODING...MIKETTA
RIP CURRENTS...DRAG
CLIMATE...CARDINALE/DRAG/GAINES
EQUIPMENT...MIKETTA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
636 PM EDT MON JUL 30 2012
.SYNOPSIS...
A HIGH PRESSURE SYSTEM OFF THE NEW ENGLAND COAST WILL SLOWLY DRIFT
SOUTHEAST AND MERGE WITH THE BERMUDA HIGH PRESSURE SYSTEM IN THE
WESTERN ATLANTIC. A COLD FRONT MOVING THROUGH THE GREAT LAKES ON
TUESDAY AND WEDNESDAY IS EXPECTED TO DISSIPATE BEFORE REACHING OUR
FORECAST AREA. ANOTHER COLD FRONT MOVING THROUGH THE GREAT LAKES
ON FRIDAY IS EXPECTED TO SUFFER A SIMILAR FATE EARLY ON THE
WEEKEND. A THIRD AND PLAUSIBLY STRONGER COLD FRONT IS FORECAST TO
REACH THE APPALACHIANS ABOUT MONDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE OVERALL SYNOPTIC PATTERN REMAINS WEAK WITH HIGH PRESSURE WELL
OFFSHORE AND LOW PRESSURE ACROSS THE NORTHERN GREAT LAKES. IT`S MUCH
THE SAME ALOFT, WEAK THAT IS. MOISTURE REMAINS RATHER ABUNDANT IN
THE LOWER LEVELS, HENCE ALL THE LOW CLOUDS ACROSS THE CWA,
ESPECIALLY EASTERN PA WHERE UPSLOPE FLOW IS BEING MAXIMIZED.
OUTSIDE OF THE SCATTERED SHOWERS FIRING WEST OF A READING,
ALLENTOWN, MOUNT POCONO LINE, PRECIPITATION IS ISOLATED. THE
PRECIPITATION IS SLOWLY DRIFTING TO THE NORTH/NORTHEAST, A MUCH
DIFFERENT ROAD THEN THE HIGH RESOLUTION HRRR SUGGESTS.
TEMPERATURES SHOULD SETTLE INTO THE 60S TONIGHT IN MOST SPOTS.
CENTER CITY COULD STILL REMAIN IN THE LOW 70S AND THE SOUTHERN
POCONOS COULD SEE SOME UPPER 50S.
THE SHOWERS AN THUNDERSTORMS WILL DISSIPATE THIS EVENING, BUT
LIKE LAST NIGHT, LOW CLOUDS WILL RETURN, PROBABLY A LITTLE EARLIER
AND A LITTLE THICKER AS THE LIGHT ONSHORE FLOW PERSISTS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
LOOKS LIKE LOTS OF CLOUDS TO START THE DAY. THEN AFTER JUST A LITTLE
BIT OF SUN, WE HAVE CHANCE POPS IN THE FORECAST AS THE MID LEVEL
TROF APPROACHES FROM THE WEST. IT APPEARS THE FOCUS OF THE
THUNDERSTORM ACTIVITY WILL BE WELL WEST OF THE CWA.
WITH ALL THE CLOUD COVER IN PLACE TOMORROW, HIGHS WILL RANGE FROM
THE UPPER 70S ACROSS THE POCONOS TO THE MID 80S ACROSS THE
DELAWARE VALLEY AND ALL POINTS SOUTH AND EAST.
WINDS WILL REMAIN ON THE LIGHT SIDE AND MAINLY FROM THE EAST,
PROBABLY MORE NORTHEAST TOMORROW MORNING AND MORE SOUTHEAST
TOMORROW AFTERNOON.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE GENERAL EVOLUTION OF THIS LONG TERM PERIOD IS A TRANSITION FROM
TROFINESS ALONG THE EASTERN SEABOARD TO A MORE ZONAL FLOW.
UNFORTUNATELY THE FORECAST SOUNDINGS ARE NOT SHOWING ENOUGH OF A CAP
TO FORECAST A DRY DAY (FRIDAY MIGHT BECOME THE ONE). HIGHEST POPS
ARE CONCENTRATED WHEN THE COLD FRONTS RUNNING ON FUMES ATTEMPT TO
PASS THROUGH OUR CWA ON WEDNESDAY AND SATURDAY. HIGHER POPS ARE THEN
WITH THE NEXT (STRONGER?) CFP LATER SUNDAY INTO MONDAY. WITH THE
RETURN OF ZONAL FLOW, TEMPERATURES WILL RESPOND AGAIN WITH MORE 90S
IN STORE. WHILE THE FRONTS PER-SE DON`T MAKE IT, THEY OFFER THE
OPPORTUNITY OF FILTERING IN SOME DRIER AIR INTO THE REGION AND ALSO
BY THEIR FCST THICKNESS FIELDS TRY TO KEEP A STATUS-QUO ON THE
HEAT. RIGHT NOW THE HEAT LOOKS LESS OPPRESSIVE THAN SOME OF THE
HOT SPELLS WE HAVE ALREADY HAD THIS SUMMER. REGARDLESS WE MIGHT
STILL REACH ADVISORY LEVELS, ESPECIALLY IN THE MORE URBANIZED
PARTS OF OUR CWA.
THE GFS INITIALIZATION AT 500MB WAS BETTER THAN THE WRF-NMMB. THE
WRF-NMMB WAS TOO SHARP WITH THE EASTERN TROF AND SUBSEQUENTLY
PRODUCED A STRONGER AND MORE CLOSER TO THE COAST LOW WHICH WE ARE
NOT FOLLOWING AT THE START OF THE LONG TERM. BEYOND THAT TOO MUCH
DAMAGE IS DONE FOR MODEL RECOVERY AND THE 12Z GFS IS GIVING US A
MIDDLE OF THE ROAD SOLUTION LOOKING AT ALL OF THE MEDIUM RANGE
MODELS.
AT THE START OF THE LONG TERM TUESDAY NIGHT, WE CARRY SOME CHANCES
ASSOCIATED WITH THE DEPARTING OFFSHORE LOW TO THE EAST AND THE
POSSIBILITY OF RESIDUAL SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
THE SHORT WAVE OF THE FIRST COLD FRONT APPROACHING FROM THE WEST.
ON WEDNESDAY WE SUPPOSE IF THE WRF-NMMB ENDS UP BEING RIGHT FOR THE
WRONG REASON, POPS MAY BE OVERDONE EAST BECAUSE OF SUBSIDENCE
BETWEEN SYSTEMS. BUT, OTHER THAN LATER SUNDAY AND THAT IS FRAUGHT WITH
UNCERTAINTIES BECAUSE ITS DAY 6 AND A HALF THIS APPEARS TO BE THE
"GO TO" DAY FOR CONVECTION AND HEAVY RAIN IN OUR CWA. FORECAST BULK
SHEAR VALUES ARE LOW. NOT TERRIBLY SOLD THAT A EML CAN SURVIVE
UNSCATHED AS THE GFS IS FORECASTING. BUT THE COMBINATION OF ROBUST
CAPE, SOME DECREASE OF THETA E WITH HEIGHT WOULD BE ENOUGH FOR
PULSE TYPE STRONG TO MAYBE SEVERE STORMS. WITH SREF PWATS NEARING
1.75 INCHES AND ENVIRONMENTAL WINDS GENERALLY LIGHT SOME HEAVY
DOWNPOURS ARE ALSO POSSIBLE. THE MORE LIKELY GEOGRAPHIC AREAS ARE
WEST BECAUSE THE FRONT SHOULD STILL BE STRONGER AND FARTHER AWAY
FROM ANY OFFSHORE LOW INFLUENCE. BECAUSE OF THE LATTER ERRORS WITH
THE WRF-NMMB, WARMER GFS PREFERRED FOR MAX TEMPS.
WE WILL LOWER OUR CHANCES WEDNESDAY NIGHT PARTLY BECAUSE OF DIURNAL
CONSIDERATIONS, BUT ALSO BECAUSE OF THE FORECAST POSITION OF THE
LONG WAVE TROF PASSING THROUGH OUR CWA.
MODELS ARE SHOWING MORE OF A CHANCE OF THUNDERSTORMS EAST WITH
RESIDUAL HIGHER THETA E VALUES. OVERALL WITH WARMER TEMPS FCST
ALOFT AS THE TROF MOVES EAST THE GENERAL COVERAGE AND STRENGTH OF
THE TSTMS SHOULD BE LESS. BECAUSE MOST OF THE MODELS ARE SHOWING
SOME "COOLING" BELOW 700MB, WE WENT SLIGHTLY LOWER THAN GFS MOS WITH
MAX TEMPS.
IF THERE IS GOING TO BE A PREVAILING DRY DAY (WITH RESPECT TO POPS),
IT MAY BE FRIDAY AS THE NEXT FRONT IS GEOGRAPHICALLY FORECAST TO BE
TOO FAR AWAY AND THERE IS FORECAST NVA IN THE ZONAL FLOW. RIGHT NOW
ONLY ISOLATED POPS WERE CARRIED AND MAINLY INLAND AND NORTH OF THE
MASON-DIXON LINE. GENERAL MODEL AGREEMENT OF A HOTTER DAY WITH
POSSIBLY SOME LOWER DEW POINTS BECAUSE MORE OF A WESTERLY FLOW ALOFT.
THE NEXT REMNANT FRONTAL IMPULSE SHOULD COME IN FRIDAY NIGHT OR
SATURDAY WHERE WE INCREASE POPS AGAIN. NOT COUNTING ON CLOUDS KEEPING
TEMPS DOWN, SO HERE WE WENT ABOVE GFS MOS GUIDANCE. THE NEXT FRONT
IS FORECAST TO APPROACH ON SUNDAY AND MONDAY WITH MODEL TIMING
DIFFERENCES. WE NORMALLY PREFER THE SLOWER ENVELOPE OF SOLUTIONS IN
THE MIDDLE OF THE SUMMER AS THESE TYPICALLY WORK BETTER. SO POPS MAY
BE TOO AGGRESSIVE ON SUNDAY AND OPTIMISTIC FOR MONDAY. MORE 90
DEGREE DAYS ARE POSSIBLE AS PER FCST 925MB TEMPS. MONDAY IS ONE OF
THOSE DAYS WHERE WE SHOULD HIT 90 ALONG THE COASTAL PLAIN EVEN IF
THE FRONT MOVES THROUGH WITH DOWNSLOPING FLOW AS SUB 15C 850MB
TEMPS ARE STILL FORECAST TO BE JUST GETTING TO THE EASTERN GREAT
LAKES IN THE MORNING.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE MAIN ISSUE DURING THIS FORECAST PERIOD IS GOING TO BE THE LOW
CLOUDS DEVELOPING TONIGHT. CURRENTLY, THERE ARE A FEW SHOWERS AND
THUNDERSTORMS NEAR KRDG, BUT THEY ARE ON THE LIGHTER/LESS INTENSE
SIDE.
WITH THE ONSHORE FLOW CONTINUING THROUGH THE NIGHT. MOISTURE WILL
INCREASE AND POOL OVER THE TERMINALS, ESPECIALLY THE ONES IN
EASTERN PA. MVFR IS A REAL GOOD BET BY 07Z TONIGHT FOR ALL THE
TERMINALS. IFR LOOKS QUITE POSSIBLE FOR KRDG AND KABE BEFORE
DAYBREAK. LOOKS LIKE MORE OF A LOW CEILING ISSUE THAN VISIBILITY
ISSUE.
WINDS REMAIN OUT OF THE EAST TOMORROW, PROBABLY MORE NORTHEAST IN
THE MORNING AND MORE SOUTHEAST IN THE AFTERNOON. LOOKS LIKE A
MVFR/VFR TYPE OF DAY WITH SCATTERED SHOWERS AND THUNDERSTORMS.
OUTLOOK...
TUESDAY NIGHT...VFR...CHANCE OF MVFR CIGS AND VSBYS MAINLY NORTH.
WEDNESDAY AND WEDNESDAY NIGHT...PRIMARILY VFR, EXCEPT MVFR TO
LOCALLY IFR IN SCATTERED SHOWERS AND THUNDERSTORMS AND FOG LATE.
THURSDAY THROUGH FRIDAY NIGHT...VFR, ISOLATED MVFR CONDITIONS IN
EARLY MORNING FOG AND MORE ISOLATED (VS WEDNESDAY) SHOWERS AND
THUNDERSTORMS.
SATURDAY...PRIMARILY VFR, BUT INCREASE CHANCES OF MVFR CONDITIONS
IN GREATER COVERAGE SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
FAIRLY TRANQUIL ACROSS AREA WATERS THE NEXT 24 HOURS. SOUTHEAST
WINDS TONIGHT WILL GO MORE NORTHEAST TOMORROW MORNING AND THEN
BACK TO SOUTHEAST TOMORROW IN THE AFTERNOON.
SEAS WILL BE AROUND 2 FEET ON THE OCEAN AND 1 TO 2 FEET ON THE BAY.
OUTLOOK...
WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS THROUGH THE OUTLOOK PERIOD. WE ARE FOLLOWING THE WEAKER
OFFSHORE LOW SOLUTIONS AT THE START OF THE OUTLOOK PERIOD AS PER
PMDHMD AND A BETTER INITIALIZATION BY THE GFS (WHICH ALSO HAS WEAKER
LOWS). THUS BOTH LOWS ARE EXPECTED TO TRACK FARTHER OFFSHORE AND NOT
GENERATE ENOUGH WINDS AND SWELLS UP TO SMALL CRAFT ADVISORY CRITERIA.
BEYOND THAT, A PAIR OF COLD FRONTS ARE FORECAST TO DISSIPATE BEFORE
REACHING THE AREA WATERS ABOUT WEDNESDAY AND AGAIN ABOUT SATURDAY. A
STRONGER FRONT AS OF NOW IS FORECAST TO APPROACH BEYOND THE END OF
OUR DETERMINISTIC FORECAST PERIOD. THE PREVAILING SOUTHERLY TO
SOUTHWESTERLY FLOW IS NOT EXPECTED TO BE STRONG ENOUGH TO PRODUCE
SMALL CRAFT ADVISORY WINDS OR SWELLS INTO SATURDAY NIGHT.
&&
.TIDES/COASTAL FLOODING...
GFS ET-SURGE GUIDANCE, AND CURRENT POSITIVE 1/2 FOOT TIDAL DEPARTURES
INDICATE THE ATLC OCEAN FRONTS OF NJ/DE WOULD SEE NEAR MARGINAL
"MINOR" TIDAL INUNDATION FLOODING WITHIN 1/2 HR OF THE NEXT THREE EVENING
HIGH TIDE AS WE APPROACH FULL MOON. THE COASTAL FLOOD STATEMENT
WAS EXPANDED TO INCLUDE THE UPPER DELAWARE BAY. REEDY POINT IS
RUNNING ABOUT 1 FOOT ABOVE PREDICTED EARLY THIS EVENING. HIGH TIDE
OCCURS IN ABOUT 3 HOURS...AND THIS TYPE OF DEPARTURE WOULD BRING
THE HIGH TIDE AT REEDY POINT CLOSE TO THE MINOR TIDAL FLOODING
BENCHMARK.
&&
.RIP CURRENTS...
FOR THE REMAINDER OF THE DAY, SOUTHEAST WINDS AROUND 10 KNOTS CAN
BE EXPECTED. WAVE HEIGHTS IN THE SURF ARE FORECAST TO RANGE FROM
2 TO 3 FEET. A CONTINUED SOUTHEAST SWELL WITH AN 11 SECOND PERIOD
SHOULD RESULT IN A MODERATE RISK OF RIP CURRENTS.
&&
.CLIMATE...
IN TERMS OF 90 DEGREE DAYS FOR THE MONTH OF JULY.
AT PHILADELPHIA 21 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
HIGHER OCCURRED THROUGH THE 29TH. THIS TIES THE RECORD FOR
THE MOST NUMBER OF 90 DEGREES DAYS ALL TIME WITH 1952, 1988, 1995
AND 2011.
AT ALLENTOWN 15 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR HIGHER
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1983, 2010 AND
2011. GREATEST IS 20 DAYS IN 1999, 1966 AND 1955.
AT WILMINGTON 17 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1952. GREATEST
IS 22 DAYS IN 1894.
AT ATLANTIC CITY 14 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
MORE OCCURRED THROUGH THE 29TH. THIS IS FIFTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 2010. GREATEST IS
21 DAYS IN 1983.
AT READING 19 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SECOND ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY. GREATEST IS 20 DAYS
SET IN 2011, 2010, 1999 AND 1955.
IN TERMS OF WARMEST AVERAGE TEMPERATURE RECORDED FOR THE MONTH OF
JULY.
AT PHILADELPHIA THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH
WAS 81.9. THIS IS THE THE THIRD WARMEST JULY ON RECORD BEHIND 1994
AND 2011.
AT WILMINGTON THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH WAS
80.5. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2011 AND 1955.
AT ATLANTIC CITY THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH
WAS 78.8. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2010 AND
2011.
AT ALLENTOWN THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH WAS
77.6 AND IS THE SEVENTH WARMEST JULY ON RECORD.
DATA SINCE 6/28...32 DAYS.
RDG ONLY 2 DAYS BELOW NORMAL
PHL/ABE/GED ONLY 3 DAYS BELOW NORMAL
TTN 4 DAYS BELOW NORMAL
MPO 5 DAYS BELOW NORMAL
ILG 6 DAYS BELOW NORMAL
ACY 9 DAYS BELOW NORMAL
90 OR HIGHER FOR THE SEASON
SO FAR TOTAL
NORMAL THIS YR LAST YR POR
ABE 17 24 21 1922
ACY 22 31
GED 29 40
ILG 27 27
PHL 21 30 33 1874
RDG 30 30
TTN 25 26
MPO 3 4
THE NORMAL AND PERIOD OF RECORD /POR/ IS LISTED FOR ONLY TWO CLIMATE
SITES WHERE THE DATASET IS EASILY AVAILABLE AND COMPLETE.
WITH RESPECT TO OCCURRENCES OF 95 OR GREATER PHL CLIMATOLOGICALLY
AVG`S 4/YR SO FAR THIS YR 12 LAST YRS TOTAL 11.
STATISTICALLY FOR PHL AS EVALUATED BY MARK DELISI...THE NUMBER OF 95
OR WARMER DAYS THIS YEAR IS UNUSUAL.
FOR OUR FORECAST AREA...
PCPN FOR THE MONTH SO FAR NOW GENERALLY WITHIN 75 PCT OF NORMAL.
TEMP FOR THE MONTH SO FAR NOW GENERALLY 2.5 TO 5F ABOVE NORMAL.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GIGI
NEAR TERM...KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...GIGI
AVIATION...DRAG/GIGI/KRUZDLO
MARINE...GIGI/KRUZDLO
TIDES/COASTAL FLOODING...KRUZDLO/HAYES
RIP CURRENTS...DRAG/KRUZDLO
CLIMATE...CARDINALE/DRAG/GAINES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
329 PM EDT MON JUL 30 2012
.SYNOPSIS...
A HIGH PRESSURE SYSTEM OFF THE NEW ENGLAND COAST WILL SLOWLY DRIFT
SOUTHEAST AND MERGE WITH THE BERMUDA HIGH PRESSURE SYSTEM IN THE
WESTERN ATLANTIC. A COLD FRONT MOVING THROUGH THE GREAT LAKES ON
TUESDAY AND WEDNESDAY IS EXPECTED TO DISSIPATE BEFORE REACHING OUR
FORECAST AREA. ANOTHER COLD FRONT MOVING THROUGH THE GREAT LAKES
ON FRIDAY IS EXPECTED TO SUFFER A SIMILAR FATE EARLY ON THE
WEEKEND. A THIRD AND PLAUSIBLY STRONGER COLD FRONT IS FORECAST TO
REACH THE APPALACHIANS ABOUT MONDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE OVERALL SYNOPTIC PATTERN REMAINS WEAK WITH HIGH PRESSURE WELL
OFFSHORE AND LOW PRESSURE ACROSS THE NORTHERN GREAT LAKES. IT`S MUCH
THE SAME ALOFT, WEAK THAT IS. MOISTURE REMAINS RATHER ABUNDANT IN
THE LOWER LEVELS, HENCE ALL THE LOW CLOUDS ACROSS THE CWA,
ESPECIALLY EASTERN PA WHERE UPSLOPE FLOW IS BEING MAXIMIZED.
OUTSIDE OF THE SCATTERED SHOWERS FIRING WEST OF A READING,
ALLENTOWN, MOUNT POCONO LINE, PRECIPITATION IS ISOLATED. THE
PRECIPITATION IS SLOWLY DRIFTING TO THE NORTH/NORTHEAST, A MUCH
DIFFERENT ROAD THEN THE HIGH RESOLUTION HRRR SUGGESTS.
TEMPERATURES SHOULD SETTLE INTO THE 60S TONIGHT IN MOST SPOTS.
CENTER CITY COULD STILL REMAIN IN THE LOW 70S AND THE SOUTHERN
POCONOS COULD SEE SOME UPPER 50S.
THE SHOWERS AN THUNDERSTORMS WILL DISSIPATE THIS EVENING, BUT
LIKE LAST NIGHT, LOW CLOUDS WILL RETURN, PROBABLY A LITTLE EARLIER
AND A LITTLE THICKER AS THE LIGHT ONSHORE FLOW PERSISTS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
LOOKS LIKE LOTS OF CLOUDS TO START THE DAY. THEN AFTER JUST A LITTLE
BIT OF SUN, WE HAVE CHANCE POPS IN THE FORECAST AS THE MID LEVEL
TROF APPROACHES FROM THE WEST. IT APPEARS THE FOCUS OF THE
THUNDERSTORM ACTIVITY WILL BE WELL WEST OF THE CWA.
WITH ALL THE CLOUD COVER IN PLACE TOMORROW, HIGHS WILL RANGE FROM
THE UPPER 70S ACROSS THE POCONOS TO THE MID 80S ACROSS THE
DELAWARE VALLEY AND ALL POINTS SOUTH AND EAST.
WINDS WILL REMAIN ON THE LIGHT SIDE AND MAINLY FROM THE EAST,
PROBABLY MORE NORTHEAST TOMORROW MORNING AND MORE SOUTHEAST
TOMORROW AFTERNOON.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE GENERAL EVOLUTION OF THIS LONG TERM PERIOD IS A TRANSITION FROM
TROFINESS ALONG THE EASTERN SEABOARD TO A MORE ZONAL FLOW.
UNFORTUNATELY THE FORECAST SOUNDINGS ARE NOT SHOWING ENOUGH OF A CAP
TO FORECAST A DRY DAY (FRIDAY MIGHT BECOME THE ONE). HIGHEST POPS
ARE CONCENTRATED WHEN THE COLD FRONTS RUNNING ON FUMES ATTEMPT TO
PASS THROUGH OUR CWA ON WEDNESDAY AND SATURDAY. HIGHER POPS ARE THEN
WITH THE NEXT (STRONGER?) CFP LATER SUNDAY INTO MONDAY. WITH THE
RETURN OF ZONAL FLOW, TEMPERATURES WILL RESPOND AGAIN WITH MORE 90S
IN STORE. WHILE THE FRONTS PER-SE DON`T MAKE IT, THEY OFFER THE
OPPORTUNITY OF FILTERING IN SOME DRIER AIR INTO THE REGION AND ALSO
BY THEIR FCST THICKNESS FIELDS TRY TO KEEP A STATUS-QUO ON THE
HEAT. RIGHT NOW THE HEAT LOOKS LESS OPPRESSIVE THAN SOME OF THE
HOT SPELLS WE HAVE ALREADY HAD THIS SUMMER. REGARDLESS WE MIGHT
STILL REACH ADVISORY LEVELS, ESPECIALLY IN THE MORE URBANIZED
PARTS OF OUR CWA.
THE GFS INITIALIZATION AT 500MB WAS BETTER THAN THE WRF-NMMB. THE
WRF-NMMB WAS TOO SHARP WITH THE EASTERN TROF AND SUBSEQUENTLY
PRODUCED A STRONGER AND MORE CLOSER TO THE COAST LOW WHICH WE ARE
NOT FOLLOWING AT THE START OF THE LONG TERM. BEYOND THAT TOO MUCH
DAMAGE IS DONE FOR MODEL RECOVERY AND THE 12Z GFS IS GIVING US A
MIDDLE OF THE ROAD SOLUTION LOOKING AT ALL OF THE MEDIUM RANGE
MODELS.
AT THE START OF THE LONG TERM TUESDAY NIGHT, WE CARRY SOME CHANCES
ASSOCIATED WITH THE DEPARTING OFFSHORE LOW TO THE EAST AND THE
POSSIBILITY OF RESIDUAL SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
THE SHORT WAVE OF THE FIRST COLD FRONT APPROACHING FROM THE WEST.
ON WEDNESDAY WE SUPPOSE IF THE WRF-NMMB ENDS UP BEING RIGHT FOR THE
WRONG REASON, POPS MAY BE OVERDONE EAST BECAUSE OF SUBSIDENCE
BETWEEN SYSTEMS. BUT, OTHER THAN LATER SUNDAY AND THAT IS FRAUGHT WITH
UNCERTAINTIES BECAUSE ITS DAY 6 AND A HALF THIS APPEARS TO BE THE
"GO TO" DAY FOR CONVECTION AND HEAVY RAIN IN OUR CWA. FORECAST BULK
SHEAR VALUES ARE LOW. NOT TERRIBLY SOLD THAT A EML CAN SURVIVE
UNSCATHED AS THE GFS IS FORECASTING. BUT THE COMBINATION OF ROBUST
CAPE, SOME DECREASE OF THETA E WITH HEIGHT WOULD BE ENOUGH FOR
PULSE TYPE STRONG TO MAYBE SEVERE STORMS. WITH SREF PWATS NEARING
1.75 INCHES AND ENVIRONMENTAL WINDS GENERALLY LIGHT SOME HEAVY
DOWNPOURS ARE ALSO POSSIBLE. THE MORE LIKELY GEOGRAPHIC AREAS ARE
WEST BECAUSE THE FRONT SHOULD STILL BE STRONGER AND FARTHER AWAY
FROM ANY OFFSHORE LOW INFLUENCE. BECAUSE OF THE LATTER ERRORS WITH
THE WRF-NMMB, WARMER GFS PREFERRED FOR MAX TEMPS.
WE WILL LOWER OUR CHANCES WEDNESDAY NIGHT PARTLY BECAUSE OF DIURNAL
CONSIDERATIONS, BUT ALSO BECAUSE OF THE FORECAST POSITION OF THE
LONG WAVE TROF PASSING THROUGH OUR CWA.
MODELS ARE SHOWING MORE OF A CHANCE OF THUNDERSTORMS EAST WITH
RESIDUAL HIGHER THETA E VALUES. OVERALL WITH WARMER TEMPS FCST
ALOFT AS THE TROF MOVES EAST THE GENERAL COVERAGE AND STRENGTH OF
THE TSTMS SHOULD BE LESS. BECAUSE MOST OF THE MODELS ARE SHOWING
SOME "COOLING" BELOW 700MB, WE WENT SLIGHTLY LOWER THAN GFS MOS WITH
MAX TEMPS.
IF THERE IS GOING TO BE A PREVAILING DRY DAY (WITH RESPECT TO POPS),
IT MAY BE FRIDAY AS THE NEXT FRONT IS GEOGRAPHICALLY FORECAST TO BE
TOO FAR AWAY AND THERE IS FORECAST NVA IN THE ZONAL FLOW. RIGHT NOW
ONLY ISOLATED POPS WERE CARRIED AND MAINLY INLAND AND NORTH OF THE
MASON-DIXON LINE. GENERAL MODEL AGREEMENT OF A HOTTER DAY WITH
POSSIBLY SOME LOWER DEW POINTS BECAUSE MORE OF A WESTERLY FLOW ALOFT.
THE NEXT REMNANT FRONTAL IMPULSE SHOULD COME IN FRIDAY NIGHT OR
SATURDAY WHERE WE INCREASE POPS AGAIN. NOT COUNTING ON CLOUDS KEEPING
TEMPS DOWN, SO HERE WE WENT ABOVE GFS MOS GUIDANCE. THE NEXT FRONT
IS FORECAST TO APPROACH ON SUNDAY AND MONDAY WITH MODEL TIMING
DIFFERENCES. WE NORMALLY PREFER THE SLOWER ENVELOPE OF SOLUTIONS IN
THE MIDDLE OF THE SUMMER AS THESE TYPICALLY WORK BETTER. SO POPS MAY
BE TOO AGGRESSIVE ON SUNDAY AND OPTIMISTIC FOR MONDAY. MORE 90
DEGREE DAYS ARE POSSIBLE AS PER FCST 925MB TEMPS. MONDAY IS ONE OF
THOSE DAYS WHERE WE SHOULD HIT 90 ALONG THE COASTAL PLAIN EVEN IF
THE FRONT MOVES THROUGH WITH DOWNSLOPING FLOW AS SUB 15C 850MB
TEMPS ARE STILL FORECAST TO BE JUST GETTING TO THE EASTERN GREAT
LAKES IN THE MORNING.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE MAIN ISSUE DURING THIS FORECAST PERIOD IS GOING TO BE THE LOW
CLOUDS DEVELOPING TONIGHT. CURRENTLY, THERE ARE A FEW SHOWERS AND
THUNDERSTORMS NEAR KRDG, BUT THEY ARE ON THE LIGHTER/LESS INTENSE
SIDE.
WITH THE ONSHORE FLOW CONTINUING THROUGH THE NIGHT. MOISTURE WILL
INCREASE AND POOL OVER THE TERMINALS, ESPECIALLY THE ONES IN
EASTERN PA. MVFR IS A REAL GOOD BET BY 07Z TONIGHT FOR ALL THE
TERMINALS. IFR LOOKS QUITE POSSIBLE FOR KRDG AND KABE BEFORE
DAYBREAK. LOOKS LIKE MORE OF A LOW CEILING ISSUE THAN VISIBILITY
ISSUE.
WINDS REMAIN OUT OF THE EAST TOMORROW, PROBABLY MORE NORTHEAST IN
THE MORNING AND MORE SOUTHEAST IN THE AFTERNOON. LOOKS LIKE A
MVFR/VFR TYPE OF DAY WITH SCATTERED SHOWERS AND THUNDERSTORMS.
OUTLOOK...
TUESDAY NIGHT...VFR...CHANCE OF MVFR CIGS AND VSBYS MAINLY NORTH.
WEDNESDAY AND WEDNESDAY NIGHT...PRIMARILY VFR, EXCEPT MVFR TO
LOCALLY IFR IN SCATTERED SHOWERS AND THUNDERSTORMS AND FOG LATE.
THURSDAY THROUGH FRIDAY NIGHT...VFR, ISOLATED MVFR CONDITIONS IN
EARLY MORNING FOG AND MORE ISOLATED (VS WEDNESDAY) SHOWERS AND
THUNDERSTORMS.
SATURDAY...PRIMARILY VFR, BUT INCREASE CHANCES OF MVFR CONDITIONS
IN GREATER COVERAGE SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
FAIRLY TRANQUIL ACROSS AREA WATERS THE NEXT 24 HOURS. SOUTHEAST
WINDS TONIGHT WILL GO MORE NORTHEAST TOMORROW MORNING AND THEN
BACK TO SOUTHEAST TOMORROW IN THE AFTERNOON.
SEAS WILL BE AROUND 2 FEET ON THE OCEAN AND 1 TO 2 FEET ON THE BAY.
OUTLOOK...
WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS THROUGH THE OUTLOOK PERIOD. WE ARE FOLLOWING THE WEAKER
OFFSHORE LOW SOLUTIONS AT THE START OF THE OUTLOOK PERIOD AS PER
PMDHMD AND A BETTER INITIALIZATION BY THE GFS (WHICH ALSO HAS WEAKER
LOWS). THUS BOTH LOWS ARE EXPECTED TO TRACK FARTHER OFFSHORE AND NOT
GENERATE ENOUGH WINDS AND SWELLS UP TO SMALL CRAFT ADVISORY CRITERIA.
BEYOND THAT, A PAIR OF COLD FRONTS ARE FORECAST TO DISSIPATE BEFORE
REACHING THE AREA WATERS ABOUT WEDNESDAY AND AGAIN ABOUT SATURDAY. A
STRONGER FRONT AS OF NOW IS FORECAST TO APPROACH BEYOND THE END OF
OUR DETERMINISTIC FORECAST PERIOD. THE PREVAILING SOUTHERLY TO
SOUTHWESTERLY FLOW IS NOT EXPECTED TO BE STRONG ENOUGH TO PRODUCE
SMALL CRAFT ADVISORY WINDS OR SWELLS INTO SATURDAY NIGHT.
&&
.TIDES/COASTAL FLOODING...
GFS ET-SURGE GUIDANCE, AND CURRENT POSITIVE 1/2 FOOT TIDAL DEPARTURES
INDICATE THE ATLC OCEAN FRONTS OF NJ/DE WOULD SEE NEAR MARGINAL
"MINOR" TIDAL INUNDATION FLOODING WITHIN 1/2 HR OF THE NEXT THREE EVENING
HIGH TIDE AS WE APPROACH FULL MOON.
&&
.RIP CURRENTS...
FOR THE REMAINDER OF THE DAY, SOUTHEAST WINDS AROUND 10 KNOTS CAN
BE EXPECTED. WAVE HEIGHTS IN THE SURF ARE FORECAST TO RANGE FROM
2 TO 3 FEET. A CONTINUED SOUTHEAST SWELL WITH AN 11 SECOND PERIOD
SHOULD RESULT IN A MODERATE RISK OF RIP CURRENTS.
&&
.CLIMATE...
IN TERMS OF 90 DEGREE DAYS FOR THE MONTH OF JULY.
AT PHILADELPHIA 21 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
HIGHER OCCURRED THROUGH THE 29TH. THIS TIES THE RECORD FOR
THE MOST NUMBER OF 90 DEGREES DAYS ALL TIME WITH 1952, 1988, 1995
AND 2011.
AT ALLENTOWN 15 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR HIGHER
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1983, 2010 AND
2011. GREATEST IS 20 DAYS IN 1999, 1966 AND 1955.
AT WILMINGTON 17 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1952. GREATEST
IS 22 DAYS IN 1894.
AT ATLANTIC CITY 14 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
MORE OCCURRED THROUGH THE 29TH. THIS IS FIFTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 2010. GREATEST IS
21 DAYS IN 1983.
AT READING 19 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SECOND ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY. GREATEST IS 20 DAYS
SET IN 2011, 2010, 1999 AND 1955.
IN TERMS OF WARMEST AVERAGE TEMPERATURE RECORDED FOR THE MONTH OF
JULY.
AT PHILADELPHIA THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH
WAS 81.9. THIS IS THE THE THIRD WARMEST JULY ON RECORD BEHIND 1994
AND 2011.
AT WILMINGTON THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH WAS
80.5. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2011 AND 1955.
AT ATLANTIC CITY THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH
WAS 78.8. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2010 AND
2011.
AT ALLENTOWN THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 29TH WAS
77.6 AND IS THE SEVENTH WARMEST JULY ON RECORD.
DATA SINCE 6/28...32 DAYS.
RDG ONLY 2 DAYS BELOW NORMAL
PHL/ABE/GED ONLY 3 DAYS BELOW NORMAL
TTN 4 DAYS BELOW NORMAL
MPO 5 DAYS BELOW NORMAL
ILG 6 DAYS BELOW NORMAL
ACY 9 DAYS BELOW NORMAL
90 OR HIGHER FOR THE SEASON
SO FAR TOTAL
NORMAL THIS YR LAST YR POR
ABE 17 24 21 1922
ACY 22 31
GED 29 40
ILG 27 27
PHL 21 30 33 1874
RDG 30 30
TTN 25 26
MPO 3 4
THE NORMAL AND PERIOD OF RECORD /POR/ IS LISTED FOR ONLY TWO CLIMATE
SITES WHERE THE DATASET IS EASILY AVAILABLE AND COMPLETE.
WITH RESPECT TO OCCURRENCES OF 95 OR GREATER
PHL CLIMATOLOGICALLY AVG`S 4/YR
SO FAR THIS YR 12
LAST YRS TOTAL 11
STATISTICALLY FOR PHL AS EVALUATED BY MARK DELISI...THE NUMBER OF 95
OR WARMER DAYS THIS YEAR IS UNUSUAL.
FOR OUR FORECAST AREA...
PCPN FOR THE MONTH SO FAR NOW GENERALLY WITHIN 75 PCT OF NORMAL.
TEMP FOR THE MONTH SO FAR NOW GENERALLY 2.5 TO 5F ABOVE NORMAL.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GIGI
NEAR TERM...KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...GIGI
AVIATION...DRAG/GIGI/KRUZDLO
MARINE...GIGI/KRUZDLO
TIDES/COASTAL FLOODING...DRAG/KRUZDLO
RIP CURRENTS...DRAG/KRUZDLO
CLIMATE...CARDINALE/DRAG/GAINES
&&
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
941 PM EDT Tue Jul 31 2012
.NEAR TERM [Through Tomorrow Morning (Updated as of 0140Z)]...
The upper level pattern remains consistent this evening with deep
layer ridging over the western two thirds of the country and deep
layer troughing over the eastern third of the country. Embedded
within the western periphery of the trough are, and have been,
multiple weak to moderately strong impulses diving south through
the Ohio and Tennessee Valleys, into the southeast. Closer to the
surface, much of the eastern U.S. is dominated by a rather weak
pressure pattern, with the subtropical ridge spreading from the
western Atlantic into the northern Gulf of Mexico.
The aforementioned pattern favors Mesoscale Convective Systems
(MCS; or a large complex of storms) riding from north to south
along the pathways taken by the upper level impulses. At this
hour, a scattering of storms can be found across the
Alabama/Georgia border, north along the Appalachian Mountain
Chain. The most daunting storms are found in southern Indiana, and
along the Central Appalachians. Model consensus, is that
instability, mid-level lapse rates, deep layer shear and deep
layer wind speed will all be on the decrease overnight. These are
all parameters necessary for the sustainability of MCSs. Thus,
confidence is rather high that storms to our north will weaken
substantially before reaching our local area overnight. Have
included a slight chance for showers across our Georgia and
Alabama counties after 2AM EDT for any residual storms that
navigate this far south.
The main concern for us overnight, will be the development of
showers and thunderstorms along the Gulf Coast in the low-level
convergent flow regime. However, there is not a single piece of
guidance that is handling the magnitude of the low-level
southwesterly flow well. Guidance is overdoing the magnitude,
thus overdoing the convection (theoretically). The amount and
magnitude of the storms is highly dependent on the strength of the
convergence, thus confidence is low as to the coverage of storms
expected along the coast overnight. Nevertheless, mariners and
coastal residents should expect at least some thunderstorm
development overnight, with a threat for waterspouts.
The forecast for tomorrow will become more clear as the several
variables above play out through the night. Tomorrow afternoon
will likely be a largely disturbed pattern with storms organizing
around mesoscale boundaries from overnight offshore convection, as
well as remaining boundaries from decaying MCSs to our north.
Since we do not expect an organized MCS overnight, the cirrus
canopy should diminish through the night and allow for enough
heating tomorrow afternoon for the seabreeze fronts to develop.
Keeping in mind the complex forecast, we surely do not expect "pure"
seabreeze driven convection, but the seabreeze should play some
role and is expected to remain pinned near the coast in the
deep northwesterly flow regime. Thus, as advertised, the highest
PoPs tomorrow are across north Florida, decreasing to the north
across S.E. Alabama and S. Georgia. The threat for severe weather
will exist again tomorrow, with the best chance across north
Florida, west of the Aucilla River. The main threat with any
severe storms that do develop will be damaging winds and
marginally severe hail.
The temperature forecast tomorrow is highly dependent on the
coverage of storms. However, it is expected to remain warmer to
our north (in the middle 90s) and cooler across north Florida
(lower 90s).
&&
.SHORT TERM [Through Thursday]...
This challenging forecast trend continues across our region for
Thursday. On Thursday expect a more typical summertime
distribution with the PoPs...low in the morning and then
increasing to about 50 percent in the afternoon nearly regionwide.
This would be more typical of a variable flow pattern for the sea
breeze. Our region will still reside in a weakness between two
ridges (one to the west and one to the east) and thus remain in a
favorable location for afternoon convection.
A slight warm up is expected for Thursday with highs warming into
the mid 90s. Lows overnight are still expected to remain in the
mid to upper 70s.
&&
.LONG TERM [Thursday Night through Tuesday]...
By Friday upper level pattern consists of a ridge over Texas and
ridging over the Atlantic. Flow across the CONUS will be mainly
zonal above the aforementioned ridge with a small trof exiting the
Atlantic coast near the Carolinas. GFS model is hinting that some
MCS features may continue to develop as they have over the past
few days and ride the ridge and enter our western CWA on Friday.
As the Atlantic ridge strengthens and pushes farther west our
prevailing flow will become more southerly. PoP chances will be
near climatological. By Monday a Low pressure system begins to
move through the Great Lakes as it propagates towards the East
Coast accompanying trough moves through our northern CWA which
could lead to enhanced rainfall chances. Through the extended
period Max/Min temps will remain near climo with Highs in the
lower to mid 90s and lows in the middle 70s.
&&
.AVIATION [Beginning 02Z Wednesday]...
With an early start to the convection at the Terminals earlier
today, due to a strong MCS which pushed south-southeastward from
Central AL Tuesday morning, the showers and storms tapered off and
ended much faster than on Monday. Since there is likely to be less
in the way of lingering mid-upper level cloud debris across the
region tonight, believe there is a greater probability of more
widespread MVFR conditions (with IFR at VLD) at the Taf sites
overnight. Difficult fcst for timing and convective coverage this
period, with much of the Global and Hi-Res Guidance showing lower
chances for showers and storms. Therefore, decided on Prob30
groups for this package at all sites, some beginning during the
morning hours. However, after just examining the latest local 23Z
WRF and 22Z HRRR runs the convection could begin earlier than
expected with some potential for a weaker MCS.
&&
.MARINE...
West to southwesterly winds are expected overnight through
Wednesday. The strength of the winds are a bit uncertain right
now, but will likely remain below headline criteria. Winds will
diminish on Thursday as the overall pattern becomes less disturbed.
&&
.FIRE WEATHER...
Relative humidity levels are expected to remain above critical
thresholds for the next several days, so red flag conditions are
not expected.
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Harrigan
SHORT TERM...Harrigan/Godsey
LONG TERM...Fournier
AVIATION...Gould
MARINE...Harrigan/Godsey
FIRE WEATHER...Wool
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
516 PM CDT MON JUL 30 2012
.DISCUSSION...
310 PM CDT
SHORT TERM...THIS EVENING THROUGH THURSDAY...
PRIMARY CONCERN IS CONVECTIVE CHANCES THIS EVENING ACROSS NORTHERN
ILLINOIS. WATER VAPOR IMAGERY TODAY SHOWS STRONG MIDLEVEL RIDGING
CENTERED OVER THE SOUTHERN PLAINS AND A FAIRLY STRONG SHORTWAVE
TROUGH OVER ONTARIO...WITH ANOTHER TROUGH OFF THE PACIFIC NORTHWEST
COAST. THE TROUGH OVER ONTARIO WILL DIG SOUTHEAST...WITH ASSOCIATED
SURFACE LOW DRAGGING COOL FRONT ACROSS LAKE MICHIGAN AND ACROSS CWA
THIS EVENING THROUGH TONIGHT.
THIS EVENING...THOUGH THE BEST FORCING IN TERMS OF POSITIVE
VORTICITY ADVECTION WILL BE FOCUSED NORTHEAST OF THE CWA CLOSER TO
THE TROUGH AXIS...IT APPEARS THERE WILL BE DECENT CONVERGENCE ALONG
AND AHEAD OF THE COOL FRONT...ALONG WITH 0-6 KM BULK SHEAR VALUES
INCREASING TO 30 TO 35 KT AND NORTHERN ILLINOIS BEING IN THE EXIT
REGION OF AN ~80 KT UPPER LEVEL JET STREAK. SO THERE IS SOME SUPPORT
FOR ORGANIZED UPDRAFTS. SUSPECT THAT THE MLCAPE BEING PROGGED THIS
BY THE NAM AND RAP ACROSS FAR NORTHERN IL...IN EXCESS OF 2500 J/KG
IS A BIT OVERDONE BECAUSE FCST SURFACE TEMPS AND DEWPOINTS ARE
LIKELY A BIT TOO HIGH...BUT THERE SHOULD STILL BE AT LEAST 1500 J/KG
TO TAP INTO...WITH MINIMAL CIN. WITH TEMPERATURES ONLY SLOWLY
COOLING AHEAD OF THE FRONT...LOW LEVEL LAPSE RATES ARE EXPECTED TO
REMAIN FAIRLY STEEP AND DRY AIR IN THE LOWER LEVELS MAY SUPPORT
DCAPE VALUES IN EXCESS OF 1000 J/KG. THUS PRIMARY THREAT WITH ANY
TSRA IS EXPECTED TO BE DAMAGING WIND GUSTS...THOUGH THE GOOD DEEP
LAYER SHEAR COULD ALSO ALLOW FOR AT LEAST MARGINALLY SEVERE HAIL.
HAVE INCREASED POPS JUST A BIT ALONG AND NORTH OF I-80...THOUGH
STILL EXPECTING SCATTERED COVERAGE AT MOST...WITH EARLY EVENING
POPS CONFINED TO CLOSER TO THE WISCONSIN BORDER...SPREADING INTO
THE CHICAGO AREA LATER IN THE EVENING. DIURNAL DECREASE IN
INSTABILITY LATER THIS EVENING AND OVERNIGHT WILL LIKELY LEND TO
DECREASE IN INTENSITY AND COVERAGE OF CONVECTION. WILL MAINTAIN
LOW POPS FOR ISOLATED SHRA/TSRA AFTER MIDNIGHT AS THE FRONT PUSHES
THROUGH. KEPT THE INHERITED SLIGHT POPS TUESDAY MORNING PORTIONS
OF NORTHWEST INDIANA MAINLY EAST OF I-65...WITH THE FRONT EXPECTED
TO ON THE DOORSTEP BY THAT TIME. THE THING TO WATCH FOR WOULD BE A
SLOWER FRONTAL TIMING...WHICH MAY ALLOW SOME INSTABILITY TO
REBUILD AND PRESENT SOME OPPORTUNITY FOR THE FAR SOUTHEAST CWA TO
SEE TSRA LATE MORNING/EARLY AFTERNOON. FOR NOW...DO NOT THINK THIS
IS A LIKELY SCENARIO AND HAVE THE WHOLE CWA DRY AFTER 15Z TUESDAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ON TUESDAY...WITH
NORTHERLY WINDS...THOUGH THE AIR MASS REALLY WONT BE MUCH COOLER.
AREAS AWAY FROM THE LAKE SHOULD ACTUALLY REACH NEAR OR A BIT ABOVE
90 UNDER FULL SUN...WITH ONSHORE WINDS KEEPING THE LAKEFRONT IN THE
MID 80S. THE MOST NOTICEABLE DIFFERENCE BEHIND THE FRONT IS EXPECTED
TO BE A DRIER AIR MASS. THUS DESPITE ABOVE NORMAL TEMPERATURES...THE
NORTHERLY BREEZE AND MANAGEABLE HUMIDITY LEVELS WILL MAKE IT A
FAIRLY COMFORTABLE DAY...ESPECIALLY CONSIDERING ALL THE EXTREME HEAT
WEVE SEEN THIS SUMMER. WEDNESDAY WILL BE SIMILARLY WARM AND
SUNNY...EXCEPT WITH MUCH LIGHTER WINDS WITH HIGH PRESSURE OVERHEAD. IF
WINDS ARENT ONSHORE TO START TO THE DAY ALONG THE LAKEFRONT...A LAKE
BREEZE SHOULD BE ABLE TO GET GOING QUICKLY WITH SUCH LIGHT FLOW OVER
THE AREA. THIS WILL AGAIN LIMIT HIGH TEMPERATURES A BIT ALONG THE
LAKESHORE.
THURSDAY PRESENTS A MORE INTERESTING SCENARIO IN TERMS OF THE HIGH
TEMPERATURE FORECAST. THE CWA WILL NOT BE IN A FAVORED AREA WITH
REGARD TO THE POSITION OF THE CENTER OF THE MIDLEVEL RIDGE...WHICH
WILL STILL BE OVER THE SOUTHERN PLAINS. HOWEVER...AN 850 MB THERMAL
RIDGE WILL PUSH INTO THE AREA WITH WARM ADVECTION BRINGING 850 MB
TEMPS TO HIGHER THAN 20C BY THE AFTERNOON...SUCH AS ON THE WELL
PERFORMING ECMWF MODEL. WITH FULL SUN AND DEEP MIXING...THIS WOULD
SUPPORT HOT TEMPERATURES IN THE MID AND UPPER 90S. HOWEVER...BOTH
THE NAM AND ECMWF...WHICH HAVE THE HOTTEST MAX TEMPS FCST...ALSO
SUGGEST FAIRLY HIGH RH AT THE MID AND UPPER LEVELS...WHICH COULD BE
IN THE FORM OF CONVECTIVE MID AND HIGH CLOUD DEBRIS. THINK CLOUDS
WILL BE THE LIMITING FACTOR FOR TEMPS ON THURSDAY...BUT WITH THE
VERY WARM THERMAL PROFILES...RAISED TEMPS A FEW DEGREES FROM
INHERITED TO MAINLY LOW 90S. IF THERE IS LESS CLOUD
COVER...CERTAINLY COULD SEE THE HOTTER TEMPS REALIZED. ALSO...WINDS
ALOFT ARE EXPECTED TO BE WEAK ENOUGH TO ALLOW FOR A LATE DAY LAKE
BREEZE TO PUSH INLAND...WHICH MAY BRING SOME MINOR COOLING.
FORCING FOR CONVECTION LOOKS RATHER WEAK AND MAINLY THURSDAY
AFTERNOON...WITH SHORT WAVE MOVING TO NORTH AND WEAK COOL FRONT
STARTING TO DROP INTO AREA...BUT WILL MAINTAIN INHERITED SLIGHT POPS
FOR NOW FOR SHRA/TSRA. MOST OF THE AREA WILL LIKELY REMAIN DRY.
RC
LONG TERM...THURSDAY EVENING THROUGH MONDAY..
SHORT WAVE MOVING THROUGH THE NORTHERN GREAT LAKES THU EVENING WITH
ASSOCIATED WEAK SURFACE TROF/FRONT DROPPING INTO NORTHERN
IL/NORTHWEST IN. WITH BEST FORCING FURTHER NORTH AND ONLY WEAK
SURFACE CONVERGENCE...AND CONSIDERING STRENGTH OF ONGOING
DROUGHT...WILL ONLY CARRY 20-30 PCT POPS. REMNANTS OF FRONT THEN
HANG UP OVER THE AREA FRIDAY BUT AGAIN WITH ONLY WEAK LOW LEVEL
CONVERGENCE AND NO UPPER LEVEL SUPPORT...WILL JUST MAINTAIN SLIGHT
CHANCE POPS FOR FRIDAY. GFS PUSHES FRONT THROUGH AND DEVELOPS EAST
WINDS OVER THE AREA FRIDAY WHILE ECMWF HAS A WEAK WISHY WASHY
SURFACE PATTERN. EITHER WAY LAKE BREEZE LIKELY TO KEEP TEMPS IN LOW
TO MID 80S LAKEFORNT BUT NEAR 90 SOUTH TOWARDS PONTIAC.
MEANWHILE MUCH MORE POTENT TROF/UPPER LOW BARRELS INTO WESTERN
CANADA COAST WED AND PLOWS THROUGH NORTHERN ROCKIES AND INTO THE
NORTHERN PLAINS THU AND FRI. THIS WILL ACT TO SHOVE UPPER RIDGE AND
ASSOCIATED HEAT DOME EASTWARD INTO THE MIDWEST AND GREAT LAKES BY
SATURDAY. SOUTHWEST FLOW AHEAD OF APPROACHING TROF PUSHES 850 TEMPS
TO AROUND 22C SATURDAY. WITH UNCERTAINTY ON CLOUD COVER HESITANT TO
RAISE TEMPS TOO MUCH. WILL GO WITH TEMPS IN LOWER 90S BUT MID TO
UPPER 90S NOT OUT OF THE QUESTION IF WE GET ENOUGH SUN. BEST CHANCE
OF WIDESPREAD RAIN IN A LONG TIME SAT AFTN AND EVENING AS STRONG
UPPER TROF/UPPER LOW MOVES THROUGH THE GREAT LAKES AND STRONG COLD
FRONT PUSHES THROUGH THE AREA. 12Z ECMWF A BITY SLOWER ON ARRIVAL OF
FRONT AND THUNDERSTORMS...MORE LIKELY SAT NIGHT INTO SUN MORNING.
TURNING COOLER AND DRIER SUN AND MON.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SOUTHWEST WINDS PREVAILING. LAKE BREEZE APPEARS TO HAVE STOPPED
MOVING WESTWARD WITHOUT REACHING ORD OR MDW.
* POTENTIAL FOR TSRA TO IMPACT ORD AFTER 00Z.
BEACHLER
//DISCUSSION...UPDATED 18Z...
A COLD FRONT WILL BE MOVING TO THE SOUTH ACROSS MN AND WI
TONIGHT...AND WILL MOVE THROUGH NORTHERN IL AND NORTHWEST IN
TUESDAY MORNING. TSRA WILL DEVELOP NEAR AND AHEAD OF THE FRONT
OVER WI THIS AFTERNOON. TSRA ARE EXPECTED TO STAY TO THE NORTH OF
THE TERMINALS...THOUGH THEY COULD GET CLOSE TO ORD AND RFD AFTER
00Z. THE CHANCES OF TSRA ACTUALLY GETTING TO THE TERMINALS IS TOO
LOW TO BE INCLUDED IN THE TAFS AT THIS TIME.
WHEN THE COLD FRONT MOVES THROUGH ON TUESDAY MORNING WINDS WILL
SHIFT FIRST TO THE WEST AND THEN TO THE NORTHWEST. THE CHICAGO
AREA TERMINALS WILL THEN SHIFT TO THE NORTHEAST IN THE AFTERNOON.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN LAKE BREEZE NOT AFFECTING ORD OR MDW.
* LOW CONFIDENCE IN POTENTIAL FOR TSRA TO REACH ORD.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY AND FRIDAY...VFR. SLIGHT CHANCE TSRA/SHRA WITH
OCCASIONAL MVFR CIGS.
SATURDAY...CHANCE OF TSRA/SHRA WITH OCCASIONAL MVFR CIGS.
SUNDAY...VFR.
JEE
&&
.MARINE...
226 PM CDT
LOW PRESSURE MOVING ACROSS SOUTHERN ONTARIO...WILL DRAG A COLD FRONT
DOWN THE LAKE TONIGHT. SOME STRONG TO SEVERE THUNDERSTORMS COULD
OCCUR ACROSS THE LAKE THIS EVENING AHEAD OF THE FRONT. ONCE THE
FRONT PASSES THE WINDS WILL SWITCH OUT OF THE NORTH UP TO 25 KT.
THESE STRONGER WINDS WILL CONTINUE ACROSS THE SOUTH HALF OF THE LAKE
DURING THE DAY ON TUESDAY. WAVES OVER 4 FEET ARE POSSIBLE ALONG THE
INDIANA NEAR SHORE WATERS. THIS COULD RESULT IN HAZARDS TO SMALL
CRAFT FOR TUESDAY EVENING THROUGH WEDNESDAY MORNING. HIGH PRESSURE
WILL BUILD IN ACROSS THE LAKE TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL RESULT IN ABATING WINDS FOR A PERIOD TUESDAY NIGHT INTO
WEDNESDAY.
THE WINDS LOOK TO TURN SOUTHERLY AT 10 TO 20 KT AGAIN BY THURSDAY AS
THE SURFACE HIGH SHIFTS EASTWARD ACROSS THE OHIO VALLEY. ANOTHER
AREA OF LOW PRESSURE MAY PUSH ANOTHER COLD FRONT ACROSS THE LAKE
LATE THURSDAY AND THURSDAY NIGHT...BRINGING ANOTHER PUSH OF NORTHERLY
FLOW DOWN THE LAKE. IN THE EXTENDED PERIOD IT APPEARS THAT A
STRONGER STORM SYSTEM MAY MOVE ACROSS THE UPPER MIDWEST AND GREAT
LAKES REGION OVER THE WEEKEND. THIS COULD PRODUCE A PERIOD OF
STRONGER WINDS ACROSS THE LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ014...10 AM TUESDAY TO 10 AM
WEDNESDAY.
IN...HIGH RIP CURRENT RISK...INZ001-INZ002...10 AM TUESDAY TO 10 AM
WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...4 PM
TUESDAY TO 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
315 PM CDT MON JUL 30 2012
.DISCUSSION...
310 PM CDT
SHORT TERM...THIS EVENING THROUGH THURSDAY...
PRIMARY CONCERN IS CONVECTIVE CHANCES THIS EVENING ACROSS NORTHERN
ILLINOIS. WATER VAPOR IMAGERY TODAY SHOWS STRONG MIDLEVEL RIDGING
CENTERED OVER THE SOUTHERN PLAINS AND A FAIRLY STRONG SHORTWAVE
TROUGH OVER ONTARIO...WITH ANOTHER TROUGH OFF THE PACIFIC NORTHWEST
COAST. THE TROUGH OVER ONTARIO WILL DIG SOUTHEAST...WITH ASSOCIATED
SURFACE LOW DRAGGING COOL FRONT ACROSS LAKE MICHIGAN AND ACROSS CWA
THIS EVENING THROUGH TONIGHT.
THIS EVENING...THOUGH THE BEST FORCING IN TERMS OF POSITIVE
VORTICITY ADVECTION WILL BE FOCUSED NORTHEAST OF THE CWA CLOSER TO
THE TROUGH AXIS...IT APPEARS THERE WILL BE DECENT CONVERGENCE ALONG
AND AHEAD OF THE COOL FRONT...ALONG WITH 0-6 KM BULK SHEAR VALUES
INCREASING TO 30 TO 35 KT AND NORTHERN ILLINOIS BEING IN THE EXIT
REGION OF AN ~80 KT UPPER LEVEL JET STREAK. SO THERE IS SOME SUPPORT
FOR ORGANIZED UPDRAFTS. SUSPECT THAT THE MLCAPE BEING PROGGED THIS
BY THE NAM AND RAP ACROSS FAR NORTHERN IL...IN EXCESS OF 2500 J/KG
IS A BIT OVERDONE BECAUSE FCST SURFACE TEMPS AND DEWPOINTS ARE
LIKELY A BIT TOO HIGH...BUT THERE SHOULD STILL BE AT LEAST 1500 J/KG
TO TAP INTO...WITH MINIMAL CIN. WITH TEMPERATURES ONLY SLOWLY
COOLING AHEAD OF THE FRONT...LOW LEVEL LAPSE RATES ARE EXPECTED TO
REMAIN FAIRLY STEEP AND DRY AIR IN THE LOWER LEVELS MAY SUPPORT
DCAPE VALUES IN EXCESS OF 1000 J/KG. THUS PRIMARY THREAT WITH ANY
TSRA IS EXPECTED TO BE DAMAGING WIND GUSTS...THOUGH THE GOOD DEEP
LAYER SHEAR COULD ALSO ALLOW FOR AT LEAST MARGINALLY SEVERE HAIL.
HAVE INCREASED POPS JUST A BIT ALONG AND NORTH OF I-80...THOUGH
STILL EXPECTING SCATTERED COVERAGE AT MOST...WITH EARLY EVENING
POPS CONFINED TO CLOSER TO THE WISCONSIN BORDER...SPREADING INTO
THE CHICAGO AREA LATER IN THE EVENING. DIURNAL DECREASE IN
INSTABILITY LATER THIS EVENING AND OVERNIGHT WILL LIKELY LEND TO
DECREASE IN INTENSITY AND COVERAGE OF CONVECTION. WILL MAINTAIN
LOW POPS FOR ISOLATED SHRA/TSRA AFTER MIDNIGHT AS THE FRONT PUSHES
THROUGH. KEPT THE INHERITED SLIGHT POPS TUESDAY MORNING PORTIONS
OF NORTHWEST INDIANA MAINLY EAST OF I-65...WITH THE FRONT EXPECTED
TO ON THE DOORSTEP BY THAT TIME. THE THING TO WATCH FOR WOULD BE A
SLOWER FRONTAL TIMING...WHICH MAY ALLOW SOME INSTABILITY TO
REBUILD AND PRESENT SOME OPPORTUNITY FOR THE FAR SOUTHEAST CWA TO
SEE TSRA LATE MORNING/EARLY AFTERNOON. FOR NOW...DO NOT THINK THIS
IS A LIKELY SCENARIO AND HAVE THE WHOLE CWA DRY AFTER 15Z TUESDAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ON TUESDAY...WITH
NORTHERLY WINDS...THOUGH THE AIR MASS REALLY WONT BE MUCH COOLER.
AREAS AWAY FROM THE LAKE SHOULD ACTUALLY REACH NEAR OR A BIT ABOVE
90 UNDER FULL SUN...WITH ONSHORE WINDS KEEPING THE LAKEFRONT IN THE
MID 80S. THE MOST NOTICEABLE DIFFERENCE BEHIND THE FRONT IS EXPECTED
TO BE A DRIER AIR MASS. THUS DESPITE ABOVE NORMAL TEMPERATURES...THE
NORTHERLY BREEZE AND MANAGEABLE HUMIDITY LEVELS WILL MAKE IT A
FAIRLY COMFORTABLE DAY...ESPECIALLY CONSIDERING ALL THE EXTREME HEAT
WEVE SEEN THIS SUMMER. WEDNESDAY WILL BE SIMILARLY WARM AND
SUNNY...EXCEPT WITH MUCH LIGHTER WINDS WITH HIGH PRESSURE OVERHEAD. IF
WINDS ARENT ONSHORE TO START TO THE DAY ALONG THE LAKEFRONT...A LAKE
BREEZE SHOULD BE ABLE TO GET GOING QUICKLY WITH SUCH LIGHT FLOW OVER
THE AREA. THIS WILL AGAIN LIMIT HIGH TEMPERATURES A BIT ALONG THE
LAKESHORE.
THURSDAY PRESENTS A MORE INTERESTING SCENARIO IN TERMS OF THE HIGH
TEMPERATURE FORECAST. THE CWA WILL NOT BE IN A FAVORED AREA WITH
REGARD TO THE POSITION OF THE CENTER OF THE MIDLEVEL RIDGE...WHICH
WILL STILL BE OVER THE SOUTHERN PLAINS. HOWEVER...AN 850 MB THERMAL
RIDGE WILL PUSH INTO THE AREA WITH WARM ADVECTION BRINGING 850 MB
TEMPS TO HIGHER THAN 20C BY THE AFTERNOON...SUCH AS ON THE WELL
PERFORMING ECMWF MODEL. WITH FULL SUN AND DEEP MIXING...THIS WOULD
SUPPORT HOT TEMPERATURES IN THE MID AND UPPER 90S. HOWEVER...BOTH
THE NAM AND ECMWF...WHICH HAVE THE HOTTEST MAX TEMPS FCST...ALSO
SUGGEST FAIRLY HIGH RH AT THE MID AND UPPER LEVELS...WHICH COULD BE
IN THE FORM OF CONVECTIVE MID AND HIGH CLOUD DEBRIS. THINK CLOUDS
WILL BE THE LIMITING FACTOR FOR TEMPS ON THURSDAY...BUT WITH THE
VERY WARM THERMAL PROFILES...RAISED TEMPS A FEW DEGREES FROM
INHERITED TO MAINLY LOW 90S. IF THERE IS LESS CLOUD
COVER...CERTAINLY COULD SEE THE HOTTER TEMPS REALIZED. ALSO...WINDS
ALOFT ARE EXPECTED TO BE WEAK ENOUGH TO ALLOW FOR A LATE DAY LAKE
BREEZE TO PUSH INLAND...WHICH MAY BRING SOME MINOR COOLING.
FORCING FOR CONVECTION LOOKS RATHER WEAK AND MAINLY THURSDAY
AFTERNOON...WITH SHORT WAVE MOVING TO NORTH AND WEAK COOL FRONT
STARTING TO DROP INTO AREA...BUT WILL MAINTAIN INHERITED SLIGHT POPS
FOR NOW FOR SHRA/TSRA. MOST OF THE AREA WILL LIKELY REMAIN DRY.
RC
LONG TERM...THURSDAY EVENING THROUGH MONDAY..
SHORT WAVE MOVING THROUGH THE NORTHERN GREAT LAKES THU EVENING WITH
ASSOCIATED WEAK SURFACE TROF/FRONT DROPPING INTO NORTHERN
IL/NORTHWEST IN. WITH BEST FORCING FURTHER NORTH AND ONLY WEAK
SURFACE CONVERGENCE...AND CONSIDERING STRENGTH OF ONGOING
DROUGHT...WILL ONLY CARRY 20-30 PCT POPS. REMNANTS OF FRONT THEN
HANG UP OVER THE AREA FRIDAY BUT AGAIN WITH ONLY WEAK LOW LEVEL
CONVERGENCE AND NO UPPER LEVEL SUPPORT...WILL JUST MAINTAIN SLIGHT
CHANCE POPS FOR FRIDAY. GFS PUSHES FRONT THROUGH AND DEVELOPS EAST
WINDS OVER THE AREA FRIDAY WHILE ECMWF HAS A WEAK WISHY WASHY
SURFACE PATTERN. EITHER WAY LAKE BREEZE LIKELY TO KEEP TEMPS IN LOW
TO MID 80S LAKEFORNT BUT NEAR 90 SOUTH TOWARDS PONTIAC.
MEANWHILE MUCH MORE POTENT TROF/UPPER LOW BARRELS INTO WESTERN
CANADA COAST WED AND PLOWS THROUGH NORTHERN ROCKIES AND INTO THE
NORTHERN PLAINS THU AND FRI. THIS WILL ACT TO SHOVE UPPER RIDGE AND
ASSOCIATED HEAT DOME EASTWARD INTO THE MIDWEST AND GREAT LAKES BY
SATURDAY. SOUTHWEST FLOW AHEAD OF APPROACHING TROF PUSHES 850 TEMPS
TO AROUND 22C SATURDAY. WITH UNCERTAINTY ON CLOUD COVER HESITANT TO
RAISE TEMPS TOO MUCH. WILL GO WITH TEMPS IN LOWER 90S BUT MID TO
UPPER 90S NOT OUT OF THE QUESTION IF WE GET ENOUGH SUN. BEST CHANCE
OF WIDESPREAD RAIN IN A LONG TIME SAT AFTN AND EVENING AS STRONG
UPPER TROF/UPPER LOW MOVES THROUGH THE GREAT LAKES AND STRONG COLD
FRONT PUSHES THROUGH THE AREA. 12Z ECMWF A BITY SLOWER ON ARRIVAL OF
FRONT AND THUNDERSTORMS...MORE LIKELY SAT NIGHT INTO SUN MORNING.
TURNING COOLER AND DRIER SUN AND MON.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTH TO SOUTHWEST WINDS PREVAILING. LAKE BREEZE APPEARS TO HAVE
STOPPED MOVING WESTWARD WITHOUT REACHING ORD OR MDW.
* POTENTIAL FOR TSRA TO IMPACT ORD AFTER 00Z.
PAW
//DISCUSSION...UPDATED 18Z...
A COLD FRONT WILL BE MOVING TO THE SOUTH ACROSS MN AND WI
TONIGHT...AND WILL MOVE THROUGH NORTHERN IL AND NORTHWEST IN
TUESDAY MORNING. TSRA WILL DEVELOP NEAR AND AHEAD OF THE FRONT
OVER WI THIS AFTERNOON. TSRA ARE EXPECTED TO STAY TO THE NORTH OF
THE TERMINALS...THOUGH THEY COULD GET CLOSE TO ORD AND RFD AFTER
00Z. THE CHANCES OF TSRA ACTUALLY GETTING TO THE TERMINALS IS TOO
LOW TO BE INCLUDED IN THE TAFS AT THIS TIME.
WHEN THE COLD FRONT MOVES THROUGH ON TUESDAY MORNING WINDS WILL
SHIFT FIRST TO THE WEST AND THEN TO THE NORTHWEST. THE CHICAGO
AREA TERMINALS WILL THEN SHIFT TO THE NORTHEAST IN THE AFTERNOON.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN LAKE BREEZE NOT AFFECTING ORD OR MDW.
* LOW CONFIDENCE IN POTENTIAL FOR TSRA TO REACH ORD.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY AND FRIDAY...VFR. SLIGHT CHANCE TSRA/SHRA WITH
OCCASIONAL MVFR CIGS.
SATURDAY...CHANCE OF TSRA/SHRA WITH OCCASIONAL MVFR CIGS.
SUNDAY...VFR.
JEE
&&
.MARINE...
226 PM CDT
LOW PRESSURE MOVING ACROSS SOUTHERN ONTARIO...WILL DRAG A COLD FRONT
DOWN THE LAKE TONIGHT. SOME STRONG TO SEVERE THUNDERSTORMS COULD
OCCUR ACROSS THE LAKE THIS EVENING AHEAD OF THE FRONT. ONCE THE
FRONT PASSES THE WINDS WILL SWITCH OUT OF THE NORTH UP TO 25 KT.
THESE STRONGER WINDS WILL CONTINUE ACROSS THE SOUTH HALF OF THE LAKE
DURING THE DAY ON TUESDAY. WAVES OVER 4 FEET ARE POSSIBLE ALONG THE
INDIANA NEAR SHORE WATERS. THIS COULD RESULT IN HAZARDS TO SMALL
CRAFT FOR TUESDAY EVENING THROUGH WEDNESDAY MORNING. HIGH PRESSURE
WILL BUILD IN ACROSS THE LAKE TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL RESULT IN ABATING WINDS FOR A PERIOD TUESDAY NIGHT INTO
WEDNESDAY.
THE WINDS LOOK TO TURN SOUTHERLY AT 10 TO 20 KT AGAIN BY THURSDAY AS
THE SURFACE HIGH SHIFTS EASTWARD ACROSS THE OHIO VALLEY. ANOTHER
AREA OF LOW PRESSURE MAY PUSH ANOTHER COLD FRONT ACROSS THE LAKE
LATE THURSDAY AND THURSDAY NIGHT...BRINGING ANOTHER PUSH OF NORTHERLY
FLOW DOWN THE LAKE. IN THE EXTENDED PERIOD IT APPEARS THAT A
STRONGER STORM SYSTEM MAY MOVE ACROSS THE UPPER MIDWEST AND GREAT
LAKES REGION OVER THE WEEKEND. THIS COULD PRODUCE A PERIOD OF
STRONGER WINDS ACROSS THE LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1222 PM CDT MON JUL 30 2012
.AVIATION...
VFR WX IS EXPECTED THROUGH 06Z/31. THERE IS STILL UNCERTAINTY
REGARDING THE POTENTIAL FOR DIURNAL CONVECTION IN THE 23Z/30 TO
03Z/31 TIME FRAME. IF DIURNAL CONVECTION WOULD DVLP IT WOULD BE
ISOLD IN NATURE AND KDBQ WOULD HAVE THE BEST CHANCE IF ANY FOR A
POSSIBLE SHRA/TSRA. AREAL COVERAGE LIKELY WILL BE 10 PERCENT OR
LESS SO NO VCSH/VCTS WAS INCLUDED IN THE 18Z TAF FOR KDBQ. AFT
06Z/31 CONTINUED LIGHT WINDS MAY ALLOW MVFR FG TO DVLP ARND
SUNRISE BUT WAS NOT INCLUDED IN THE 18Z TAFS. ..08..
&&
.PREV DISCUSSION... /ISSUED 1106 AM CDT MON JUL 30 2012/
UPDATE...
AN UPDATE TO THE FCST HAS BEEN DONE TO REFLECT CURRENT TRENDS.
RAIN FROM THE DECAYING MISSOURI MCS WILL REMAIN JUST SOUTH OF THE
CWFA LATE THIS MORNING AND INTO THE EARLY AFTERNOON HOURS. CLOUD
COVER FROM THE MCS WILL HELP SUPPRESS TEMPERATURES A COUPLE OF
DEGREES IN THE FAR SOUTH. SATELLITE TRENDS DO SHOW THE CLOUD
COVER IS SLOWLY THINNING WITH TIME.
LIGHT WINDS ACROSS THE AREA IS ALLOWING DEW POINTS TO CLIMB HIGHER
THAN PREVIOUSLY THOUGHT. HOWEVER...BASED ON PROJECTED MAX
TEMPERATURES AND DEW POINTS THE HEAT INDEX READINGS SHOULD ONLY
REACH THE MID 90S WITH PERHAPS SOME LOCALIZED UPPER 90S.
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND EVENING ACROSS THE
CWFA IS STILL UNCERTAIN. CONVECTIVE TEMPERATURES ON THE 12Z
SOUNDINGS RANGED FROM THE LOW 80S TO THE LOW 90S. RAP TRENDS
INDICATE CONVECTIVE TEMPERATURES WILL CLIMB INTO THE MID AND UPPER
90S ACROSS THE CWFA DURING THE AFTERNOON HOURS. THUS CONVECTION
THIS AFTERNOON APPEARS DOUBTFUL.
THE QUESTION THEN BECOMES WILL THE WEAK FRONT BE STRONG ENOUGH TO
INITIATE CONVECTION LATE THIS AFTERNOON AND EARLY EVENING AS THE
ATMOSPHERE COOLS. THE BETTER FORCING IS NORTHEAST OF THE CWFA AS
IS THE BETTER DIFFLUENCE ALOFT. FOR NOW WILL CONTINUE WITH THE
CURRENT SCHC/LOW CHC POPS IN THE NORTH/NORTHEAST CWFA FOR THE
EVENING HOURS. HOWEVER...THE PROBABILITY OF SOMETHING HAPPENING
IS NOT HIGH. ..08..
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1106 AM CDT MON JUL 30 2012
.UPDATE...
AN UPDATE TO THE FCST HAS BEEN DONE TO REFLECT CURRENT TRENDS.
RAIN FROM THE DECAYING MISSOURI MCS WILL REMAIN JUST SOUTH OF THE
CWFA LATE THIS MORNING AND INTO THE EARLY AFTERNOON HOURS. CLOUD
COVER FROM THE MCS WILL HELP SUPPRESS TEMPERATURES A COUPLE OF
DEGREES IN THE FAR SOUTH. SATELLITE TRENDS DO SHOW THE CLOUD
COVER IS SLOWLY THINNING WITH TIME.
LIGHT WINDS ACROSS THE AREA IS ALLOWING DEW POINTS TO CLIMB HIGHER
THAN PREVIOUSLY THOUGHT. HOWEVER...BASED ON PROJECTED MAX
TEMPERATURES AND DEW POINTS THE HEAT INDEX READINGS SHOULD ONLY
REACH THE MID 90S WITH PERHAPS SOME LOCALIZED UPPER 90S.
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND EVENING ACROSS THE
CWFA IS STILL UNCERTAIN. CONVECTIVE TEMPERATURES ON THE 12Z
SOUNDINGS RANGED FROM THE LOW 80S TO THE LOW 90S. RAP TRENDS
INDICATE CONVECTIVE TEMPERATURES WILL CLIMB INTO THE MID AND UPPER
90S ACROSS THE CWFA DURING THE AFTERNOON HOURS. THUS CONVECTION
THIS AFTERNOON APPEARS DOUBTFUL.
THE QUESTION THEN BECOMES WILL THE WEAK FRONT BE STRONG ENOUGH TO
INITIATE CONVECTION LATE THIS AFTERNOON AND EARLY EVENING AS THE
ATMOSPHERE COOLS. THE BETTER FORCING IS NORTHEAST OF THE CWFA AS
IS THE BETTER DIFFLUENCE ALOFT. FOR NOW WILL CONTINUE WITH THE
CURRENT SCHC/LOW CHC POPS IN THE NORTH/NORTHEAST CWFA FOR THE
EVENING HOURS. HOWEVER...THE PROBABILITY OF SOMETHING HAPPENING
IS NOT HIGH. ..08..
&&
.PREV DISCUSSION... /ISSUED 700 AM CDT MON JUL 30 2012/
UPDATE...
WEAKENING MCS HAS MOVED INTO NORTHWEST MO AND WAS SPREADING A
CIRRUS SHIELD INTO PORTIONS OF EASTERN IA...WESTERN IL AND
NORTHEAST MO. OTHERWISE COLD FRONT EXTENDED FROM NORTHERN MN TO
NORTHERN SD AND WAS MOVING SOUTHEAST. EXPECT AS THE MCS CONTINUES
TO WEAKEN THE CIRRUS WILL THIN ALLOWING FOR HEATING TO TAKE PLACE
AHEAD OF THE ADVANCING COLD FRONT. GRIDS UNCHANGED AT THIS TIME.
AVIATION...
VFR CONDS TODAY AND TONIGHT. THERE WILL BE ISOLATED TO SCATTERED
THUNDERSTORMS DEVELOPING ALONG A COLD FRONT LATE THIS AFTERNOON
AND EVENING. WILL CARRY VCTS AT KCID/KDBQ/KMLI LEAVING IT OUT OF
KBRL FOR NOW. SOUTHEAST WINDS LESS THAN 10 KNOTS TODAY BECOMING
NORTHWEST BEHIND THE FRONT TONIGHT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
601 PM MDT TUE JUL 31 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 226 PM MDT TUE JUL 31 2012
15Z WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED LARGE
ANTICYCLONIC CIRCULATION ALOFT IN PLACE ACROSS THE SOUTHERN PLAINS
WITH CWA ON NORTHERN PERIPHERY OF CIRCULATION...WITH ANOTHER SHORT
WAVE TROUGH NOTED UPSTREAM ALONG THE UTAH AND COLORADO BORDER. 12Z
RAOBS INDICATED LITTLE CHANGE OVER THE PAST 24 HOURS ASIDE FROM SOME
LOW LEVEL DRYING AT LBF...WITH STEEP LAPSE RATES STILL OBSERVED
MAINLY BETWEEN H7 AND H6 AT BOTH DDC AND DNR.
MAIN SHORT TERM ISSUE WILL BE PRECIPITATION CHANCES LATE THIS
AFTERNOON AND EVENING.
TONIGHT...OVERALL PATTERN HAS CHANGED LITTLE FROM YESTERDAY WITH
LARGE SCALE RIDGE REMAINING TO THE SOUTH OF THE AREA AND SHORT WAVE
TROUGH MOVING OVER THE TOP OF THE RIDGE TONIGHT. OVERALL INSTABILITY
AND PW PROFILES SIMILAR AS WELL...WITH ONLY LOW LEVEL SHEAR BEING
NOTICEABLY WEAKER THAN YESTERDAY. WITH CU FIELDS DEVELOPING OVER THE
HIGHER TERRAIN AND NEAR MESOLOW NOTED OVER YUMA COUNTY...FAIRLY
LARGE LCLS IN PLACE FAVORING STRONG COLD POOLS AND MCS VECTORS
FAVORING EASTWARD MOTION INTO STRONGER INSTABILITY ACROSS THE CWA
THINK CHANCES FOR ANOTHER ROUND OF PRECIPITATION FAIRLY GOOD
ACROSS MUCH OF THE CWA...BUT UNTIL SOME ECHOES BEGIN TO DEVELOP
DOWNSTREAM AM HESITANT TO GO MUCH ABOVE THE 40-50% RANGE FOR POPS
ATTM. BEST TIMING FOR PRECIP LOOKS TO BE IN THE 00-04Z RANGE...BUT
WITH LINGERING WAA THROUGH THE NIGHT THINK AT LEAST A FEW WEAK
SHOWERS WILL CONTINUE THROUGH THE EARLY MORNING HOURS.
TEMPERATURES SHOULD BE FAIRLY SIMILAR TO WHAT OCCURRED LAST NIGHT
WITH WET BULB TEMPS WITH THUNDERSTORMS LIKELY BRINGING TEMPS DOWN
INTO THE 60S AS STORMS PASS RESULTING IN AT LEAST FEW LOCATIONS
SEEING LOW TEMPS OCCURRING EARLIER THAN NORMAL. WITH HIGH
PRECIPITABLE WATERS AND DEEP WARM CLOUD LAYER/FREEZING LEVEL
AROUND 17 KFT MSL...HEAVY RAIN WILL BE A THREAT BUT THINK OVERALL
MCS MOTION WILL BE FAST ENOUGH TO LIMIT ANY WIDESPREAD FLASH FLOOD
THREAT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 226 PM MDT TUE JUL 31 2012
H5 RIDGE WILL BEGIN TO FLATTEN WITH WESTERLY ZONAL FLOW
DEVELOPING OVER THE NORTHERN PLAINS. THIS WILL ALLOW FOR A SERIES OF
STRONGER SHORTWAVE TROUGHS TO MOVE THROUGH THE NORTHERN PLAINS...AND
ASSOCIATED COLD FRONTS TO DROP SOUTH TOWARDS THE CWA.
THE FIRST OF THESE FRONT WILL ARRIVE LATE WEDNESDAY EVENING.
INSTABILITY AND MOISTURE WILL REMAIN IN PLACE THROUGH THE DAY
WEDNESDAY...WITH INITIATION DURING THE AFTERNOON FOLLOWING SIMILAR
PATTERN AS THE LAST FEW NIGHTS IN THE WEST/NORTHWEST. ISOLATED
ACTIVITY SHOULD INCREASE IN COVERAGE DURING THE EVENING HOURS AS
THUNDERSTORMS BECOME MORE ORGANIZED UNDER WEAK FLOW. DIFFERENCE WILL
BE WITH LARGE SCALE ASSOCIATED WITH COLD FRONT IN THE EVENING
HOURS...WHICH COULD HELP WITH COVERAGE/STRENGTH OF THUNDERSTORMS.
SOUNDINGS APPEAR TO BE DRIER THAN THE LAST FEW DAYS...HOWEVER PWAT
VALUES OVER 1 INCH ARE STILL BEING ADVERTISED. DEPENDING ON THE
TIMING OF THE FRONT POSITION OF THE BEST THUNDERSTORM COVERAGE COULD
BE PUSHED TO THE SOUTH AND EAST QUICKER THAN CURRENTLY
ADVERTISED...SO I WAS NOT CONFIDENT ENOUGH TO GO HIGHER THAN 40 POPS
DURING THE EVENING.
WEAK SHORTWAVE TROUGHS WILL CONTINUE TO MOVE NORTH OF THE CWA ON
THURSDAY...HOWEVER WITH POST FRONTAL AIRMASS IN PLACE I HAVE
QUESTIONS TO HOW MUCH SURFACE BASE AND MIXED LAYER CAPE WILL
BE AROUND TO INITIATE THUNDERSTORMS. FOR NOW I HAVE KEPT POPS
LIMITED TO 20 RANGE THU/THU NIGHT. BETTER CHANCES RETURN FRIDAY
NIGHT WHEN A STRONGER TROUGH MOVES THROUGH THE NORTHERN PLAINS AND
ANOTHER COLD FRONT DROPS SOUTH ACROSS THE CWA. HAVE INCREASED POPS
TO CHANCE CATEGORY. GUIDANCE CONTINUES TO SHOW CHANCES LINGERING
THROUGH SATURDAY NIGHT AS ADDITIONAL WEAKER SHORTWAVES MOVE
THROUGH THE AREA ON NORTHERN EXTENT OF RIDGE. CONFIDENCE IS LOWER
ON THIS ACTIVITY...SO I LIMITED IT TO SLIGHT CHANCE.
TEMPERATURES ON WEDNESDAY AND THURSDAY SHOULD BE AROUND OR ABOVE
100F WITH GOOD WAA AHEAD OF APPROACHING COLD FRONTS. BEHIND THE
FRONT ON THURSDAY AFTERNOON TEMPS WILL BE IN THE MID TO UPPER
90S...WITH NEAR NORMAL TEMPERATURES ON SATURDAY IN THE UPPER 80S/LOW
90S. THE H5 RIDGE WILL BEGIN TO BUILD NORTH AGAIN AND STRENGTHEN
SUNDAY INTO EARLY NEXT WEEK AND BRING US BACK TO 100 DEGREE
TEMPERATURES AND A DRIER PATTERN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 532 PM MDT TUE JUL 31 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD EXCEPT AROUND
KGLD BETWEEN ABOUT 02-04Z WHEN SCATTERED THUNDERSTORMS WILL MOVE
THROUGH THE AREA FROM THE WEST. GUSTY WINDS AND HEAVY RAIN ARE
POSSIBLE WITH THE STORMS ALONG WITH CONDITIONS POSSIBLY GOING TO
MVFR BRIEFLY. STORMS AND REMAINING SHOWERS WILL DISSIPATE ACROSS
THE REGION AFTER 08Z WITH ANOTHER ROUND OF ISOLATED TO SCATTERED
EVENING SHOWERS ON WEDNESDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...DR
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
351 PM CDT MON JUL 30 2012
...UPDATED FOR LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1158 AM CDT MON JUL 30 2012
AN UPPER LEVEL HIGH CONTINUED TO GRIP THE CENTRAL AND SOUTHERN GREAT
PLAINS. THE CENTER OF THE HIGH AT 500MB WAS LOCATED ACROSS THE
SOUTHERN TEXAS PANHANDLE PER RAOB AND RAP ANALYSIS AS OF 30.12Z. AN
ARC OF MID LEVEL MOISTURE COULD BE SEEN ON WATER VAPOR LOOP AND RAOB
ANALYSIS FROM WESTERN/CENTRAL ARIZONA THROUGH UTAH AND NORTHEAST TO
SOUTHEASTERN WYOMING AND WESTERN NEBRASKA. ALL ALONG THIS MOISTURE
ARC...THERE WERE MINOR MID LEVEL PERTURBATIONS IN THE FLOW PATTERN
DUE TO LATENT HEAT RELEASE FROM VARIOUS THUNDERSTORM CLUSTERS. A
MESOSCALE CONVECTIVE SYSTEM MOVED ACROSS SOUTHERN NEBRASKA/NORTHERN
KANSAS DURING THE OVERNIGHT HOURS WITH THE MID LEVEL POTENTIAL
VORTICITY ANOMALY TIED TO THIS MCS MOVING INTO EASTERN KS/WESTERN
MO. ADDITIONAL MID LEVEL VORTICITY COULD BE SEEN IN THE RAP ANALYSIS
MOVING INTO NORTHERN COLORADO WITH A 30-40 KNOT 400MB SPEED MAX
ROTATING NORTH-NORTHEASTWARD INTO THE COLORADO ROCKIES. IN THE LOWER
TROPOSPHERE...A STATIONARY FRONT EXTENDED FROM ROUGHLY BEAVER, OK TO
BUCKLIN, KS TO NEAR PRATT, KS AT 16Z. OKLAHOMA MESONET OBSERVATIONS
AT 1650Z REVEALED AN AXIS OF 102 TO 104F TEMPERATURES ACROSS
WEST-CENTRAL OKLAHOMA ON WEST-SOUTHWEST SURFACE WINDS SOUTH OF THIS
BOUNDARY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 244 PM CDT MON JUL 30 2012
WITH THE AFTERNOON FORECAST UPDATE...WILL LOWER THE POPS DOWN TO
10-14 PERCENT FOR AREAS ALONG THE STATIONARY FRONT AS CONVERGENCE
ALONG THE FRONT IS QUITE WEAK AND THERE HAS BEEN A LACK OF CUMULUS
DEVELOPMENT THROUGH 1930Z. IF ANYTHING DOES DEVELOP...THE COVERAGE
WILL BE VERY ISOLATED AND ANY INDIVIDUAL STORM WILL BE SMALL. WILL
BE TURNING THE ATTENTION TO THE WEST LATER ON THIS EVENING AND
DURING THE OVERNIGHT HOURS AS AN MCS MAY DEVELOP IN THE POST-FRONTAL
LIGHT UPSLOPE WINDS WITH DEWPOINTS IN THE MID TO UPPER 50S ACROSS
EAST-CENTRAL COLORADO AND WEST-CENTRAL/SOUTHWEST KANSAS ALONG AND
NORTH OF THE FRONT. VARIOUS HIGH-RESOLUTION CONVECTION-ALLOWING
MODELS SUGGEST HIGHER TERRAIN STORMS WILL MANAGE TO HOLD TOGETHER TO
THE KANSAS STATE BORDER...SO WILL HAVE 30 POPS GOING ACROSS THE
WESTERN COUNTIES AND 20 POPS AS FAR EAST AS ROUGHLY HIGHWAY 83.
LATE TONIGHT INTO TOMORROW...THE CONVECTIVE OUTFLOW FROM WHATEVER
REMAINS OF THE MCS TONIGHT WILL PUSH THE STATIONARY FRONT FARTHER
SOUTH THAN WHERE IT IS NOW WITH A WEAK WAVE DEVELOPING ALONG THE
FRONT ACROSS SOUTH-CENTRAL KS BY DAYBREAK TUESDAY. WEST OF THE
WAVE...WINDS AT THE SURFACE WILL LIKELY BE MORE NORTHERLY ACROSS
MUCH OF THE DDC FORECAST AREA. TOMORROW`S FORECAST HIGH TEMPERATURE
HAS BEEN LOWERED TO MID-UPPER 90S FROM HAYS TO CIMARRON TO HUGOTON
AND POINTS WEST TO THE COLORADO BORDER. EVEN THE AREAS ACROSS SOUTH
CENTRAL KANSAS WILL BE SLIGHTLY NORTH OF THE FRONT MORE THAN LIKELY
AND HAVE LOWERED THE HIGHS IN MEDICINE LODGE AREA DOWN TO ABOUT
103-104F (WHICH MAY STILL BE A BIT TOO WARM IF THE FRONT ENDS UP
BEING JUST SOUTH OF THERE). AS FAR AS THUNDERSTORM POTENTIAL GOES
TOMORROW...IT WILL BE VERY SIMILAR TO TODAY...WITH THE GENERAL
THINKING BEING THAT ANYTHING THAT WOULD DEVELOP ALONG THE FRONT
WOULD BE VERY ISOLATED IN NATURE WITH THE MOST COHERENT CONVECTION
FORMING ONCE AGAIN OVER EASTERN COLORADO. WILL BE KEEPING POPS BELOW
15 EXCEPT NEAR THE COLORADO BORDER FOR LATE IN THE AFTERNOON TUESDAY
AS A RESULT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 336 PM CDT MON JUL 30 2012
AN UPPER LEVEL RIDGE WILL REMAIN ACROSS THE SOUTHERN PLAINS
WEDNESDAY AND THURSDAY, WITH WESTERN KANSAS LOCATED ALONG THE
SOUTHERN EDGE OF THE WESTERLIES NEAR A QUASI-STATIONARY SURFACE
FRONT. ORDINARILY THIS KIND OF PATTERN COULD RESULT IN ISOLATED
THUNDERSTORMS. BUT THIS YEAR THE LOW-LEVEL MOISTURE IS JUST VERY
LIMITED. NEVERTHELESS, ISOLATED THUNDERSTORMS CANNOT BE RULED OUT
EITHER DAY. TEMPERATURES WILL CONTINUE TO BE HOT, ESPECIALLY
SOUTH OF THE FRONT OVER SOUTH CENTRAL AND PARTS OF SOUTHWEST
KANSAS TO THE SOUTH OF THE FRONT.
ALTHOUGH THERE ARE SLIGHT DIFFERENCES IN MODEL TIMING, A STRONG
SHORTWAVE TROUGH IS ADVERTISED TO DIG INTO THE NORTHERN ROCKIES
FRIDAY AND THEN PASS ACROSS THE NORTHERN PLAINS BY SATURDAY.
AN OLD FRONT WILL STILL BE STALLED OUT ACROSS SOUTHWEST KANSAS, AND
A REINFORCING COLD FRONT WILL APPROACH KANSAS WITH THE NORTHERN
STREAM SYSTEM BY SATURDAY OR SATURDAY NIGHT. THERE WILL BE ADDITIONAL
SMALL CHANCES FOR THUNDERSTORMS EACH DAY, WITH THE EXACT LOCATION
DEPENDING ON WHERE THE FRONTAL BOUNDARIES ARE. IT WILL STILL BE HOT,
ESPECIALLY SOUTH OF THE FRONTS OVER SOUTH CENTRAL KANSAS, WITH HIGHS
ABOVE 105F FOR BOTH FRIDAY AND SATURDAY. SLIGHTLY COOLER TEMPERATURES
CAN BE EXPECTED IN WEST CENTRAL KANSAS. SLIGHTLY COOLER
TEMPERATURES ARE EXPECTED BY SUNDAY AND MONDAY ACROSS MOST OF
SOUTHWEST KANSAS AFTER THE AFOREMENTIONED SHORTWAVE TROUGH PUSHES
A COLD FRONT THROUGH KANSAS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1158 AM CDT MON JUL 30 2012
A WEAK STATIONARY FRONT WILL PERSIST ACROSS SOUTHWEST KANSAS THROUGH
TODAY AND TONIGHT. WHILE AN ISOLATED THUNDERSTORM MAY DEVELOP LATE
IN THE AFTERNOON/EVENING ANYWHERE ALONG THIS BOUNDARY...THE COVERAGE
IS NOT EXPECTED TO BE ENOUGH TO JUSTIFY INCLUSION IN THE TAFS. WILL
HOWEVER INCLUDE A PROB30 GROUP FOR THUNDERSTORMS AT GCK DURING THE
OVERNIGHT HOURS AS THERE IS A GREATER PROBABILITY OF A SMALL CLUSTER
OF STORMS TO MOVE EAST OUT OF EASTERN COLORADO AND PERHAPS AFFECT
GCK ALONG/NORTH OF THE MENTIONED STATIONARY FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 72 100 75 104 / 10 10 20 10
GCK 71 96 73 103 / 20 10 20 20
EHA 70 98 73 103 / 30 20 20 20
LBL 71 99 74 104 / 20 10 20 10
HYS 71 98 75 103 / 10 10 20 10
P28 75 104 78 108 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
246 PM CDT MON JUL 30 2012
...UPDATED SHORT TERM SECTION...
.SYNOPSIS...
ISSUED AT 1158 AM CDT MON JUL 30 2012
AN UPPER LEVEL HIGH CONTINUED TO GRIP THE CENTRAL AND SOUTHERN GREAT
PLAINS. THE CENTER OF THE HIGH AT 500MB WAS LOCATED ACROSS THE
SOUTHERN TEXAS PANHANDLE PER RAOB AND RAP ANALYSIS AS OF 30.12Z. AN
ARC OF MID LEVEL MOISTURE COULD BE SEEN ON WATER VAPOR LOOP AND RAOB
ANALYSIS FROM WESTERN/CENTRAL ARIZONA THROUGH UTAH AND NORTHEAST TO
SOUTHEASTERN WYOMING AND WESTERN NEBRASKA. ALL ALONG THIS MOISTURE
ARC...THERE WERE MINOR MID LEVEL PERTURBATIONS IN THE FLOW PATTERN
DUE TO LATENT HEAT RELEASE FROM VARIOUS THUNDERSTORM CLUSTERS. A
MESOSCALE CONVECTIVE SYSTEM MOVED ACROSS SOUTHERN NEBRASKA/NORTHERN
KANSAS DURING THE OVERNIGHT HOURS WITH THE MID LEVEL POTENTIAL
VORTICITY ANOMALY TIED TO THIS MCS MOVING INTO EASTERN KS/WESTERN
MO. ADDITIONAL MID LEVEL VORTICITY COULD BE SEEN IN THE RAP ANALYSIS
MOVING INTO NORTHERN COLORADO WITH A 30-40 KNOT 400MB SPEED MAX
ROTATING NORTH-NORTHEASTWARD INTO THE COLORADO ROCKIES. IN THE LOWER
TROPOSPHERE...A STATIONARY FRONT EXTENDED FROM ROUGHLY BEAVER, OK TO
BUCKLIN, KS TO NEAR PRATT, KS AT 16Z. OKLAHOMA MESONET OBSERVATIONS
AT 1650Z REVEALED AN AXIS OF 102 TO 104F TEMPERATURES ACROSS
WEST-CENTRAL OKLAHOMA ON WEST-SOUTHWEST SURFACE WINDS SOUTH OF THIS
BOUNDARY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 244 PM CDT MON JUL 30 2012
WITH THE AFTERNOON FORECAST UPDATE...WILL LOWER THE POPS DOWN TO
10-14 PERCENT FOR AREAS ALONG THE STATIONARY FRONT AS CONVERGENCE
ALONG THE FRONT IS QUITE WEAK AND THERE HAS BEEN A LACK OF CUMULUS
DEVELOPMENT THROUGH 1930Z. IF ANYTHING DOES DEVELOP...THE COVERAGE
WILL BE VERY ISOLATED AND ANY INDIVIDUAL STORM WILL BE SMALL. WILL
BE TURNING THE ATTENTION TO THE WEST LATER ON THIS EVENING AND
DURING THE OVERNIGHT HOURS AS AN MCS MAY DEVELOP IN THE POST-FRONTAL
LIGHT UPSLOPE WINDS WITH DEWPOINTS IN THE MID TO UPPER 50S ACROSS
EAST-CENTRAL COLORADO AND WEST-CENTRAL/SOUTHWEST KANSAS ALONG AND
NORTH OF THE FRONT. VARIOUS HIGH-RESOLUTION CONVECTION-ALLOWING
MODELS SUGGEST HIGHER TERRAIN STORMS WILL MANAGE TO HOLD TOGETHER TO
THE KANSAS STATE BORDER...SO WILL HAVE 30 POPS GOING ACROSS THE
WESTERN COUNTIES AND 20 POPS AS FAR EAST AS ROUGHLY HIGHWAY 83.
LATE TONIGHT INTO TOMORROW...THE CONVECTIVE OUTFLOW FROM WHATEVER
REMAINS OF THE MCS TONIGHT WILL PUSH THE STATIONARY FRONT FARTHER
SOUTH THAN WHERE IT IS NOW WITH A WEAK WAVE DEVELOPING ALONG THE
FRONT ACROSS SOUTH-CENTRAL KS BY DAYBREAK TUESDAY. WEST OF THE
WAVE...WINDS AT THE SURFACE WILL LIKELY BE MORE NORTHERLY ACROSS
MUCH OF THE DDC FORECAST AREA. TOMORROW`S FORECAST HIGH TEMPERATURE
HAS BEEN LOWERED TO MID-UPPER 90S FROM HAYS TO CIMARRON TO HUGOTON
AND POINTS WEST TO THE COLORADO BORDER. EVEN THE AREAS ACROSS SOUTH
CENTRAL KANSAS WILL BE SLIGHTLY NORTH OF THE FRONT MORE THAN LIKELY
AND HAVE LOWERED THE HIGHS IN MEDICINE LODGE AREA DOWN TO ABOUT
103-104F (WHICH MAY STILL BE A BIT TOO WARM IF THE FRONT ENDS UP
BEING JUST SOUTH OF THERE). AS FAR AS THUNDERSTORM POTENTIAL GOES
TOMORROW...IT WILL BE VERY SIMILAR TO TODAY...WITH THE GENERAL
THINKING BEING THAT ANYTHING THAT WOULD DEVELOP ALONG THE FRONT
WOULD BE VERY ISOLATED IN NATURE WITH THE MOST COHERENT CONVECTION
FORMING ONCE AGAIN OVER EASTERN COLORADO. WILL BE KEEPING POPS BELOW
15 EXCEPT NEAR THE COLORADO BORDER FOR LATE IN THE AFTERNOON TUESDAY
AS A RESULT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 AM CDT MON JUL 30 2012
.MONDAY NIGHT THROUGH THURSDAY...
THE LARGE UPPER LEVEL HIGH WILL BE THE MAIN FEATURE DURING THE
EXTENDED FORECAST AND BE LOCATED ACROSS THE CENTRAL PART OF THE
UNITED STATES WITH AN UPPER LEVEL LONG WAVE TROUGH POSITIONED ACROSS
THE EASTERN CONUS. A PERSISTENT FRONTAL BOUNDARY AT THE SURFACE WILL
BE LOCATED ACROSS WEST CENTRAL AND CENTRAL KANSAS WHICH WILL BE THE
MAIN AREA WHERE CONVECTION COULD OCCUR DURING THE AFTERNOON AND
EVENING HOURS. OTHERWISE EXPECT PARTLY CLOUDY SKIES ACROSS WESTERN
KANSAS. VERY WARM CONDITIONS WILL CONTINUE DURING THIS TIME FRAME
WITH HIGHS RANGING FROM AROUND 100 TO 110 WITH LOWS ONLY DIPPING
INTO THE LOWER TO MID 70S.
.THURSDAY NIGHT THROUGH SATURDAY...
THE AFOREMENTIONED UPPER LEVEL HIGH WILL BE PUSHED SOUTHWARD AS A
STRONG UPPER LEVEL LOW MOVES ACROSS THE NORTHERN PLAINS AND CENTRAL
CANADA. THIS FEATURE WILL HELP PUSH A SECOND FRONT DOWN THROUGH
WESTERN KANSAS. RAIN CHANCES WILL INCREASE ACROSS AS THIS COLD FRONT
MOVES THROUGH THE AREA BUT I HAVE KEPT POPS LOW DUE TO THE
UNCERTAINTY OF SPEED AND INTENSITY OF THIS SYSTEM. THIS FRONT SHOULD
ALLOW TEMPERATURES TO DECREASE SLIGHTLY WITH HIGHS RANGING FROM THE
UPPER 90S TO 103 DEGREES AND LOWS IN THE LOWER TO MID 70S.
.SATURDAY NIGHT THROUGH SUNDAY NIGHT...
THE WEATHER PATTERN BECOMES MORE UNCERTAIN SATURDAY NIGHT THROUGH
SUNDAY AS THE GFS KEEPS THE UPPER LEVEL HIGH ACROSS THE SOUTHERN
ROCKIES AND THE ECMWF REBUILDS THE HIGH OVER THE CENTRAL PLAINS.
NEVERTHELESS, BOTH SOLUTIONS WILL BRING PARTLY CLOUDY SKIES AND DRY
CONDITIONS ACROSS WESTERN KANSAS. HIGHS THROUGH THIS TIME FRAME WILL
GENERALLY BE AROUND 100 DEGREES WITH LOWS REMAINING IN THE LOWER TO
MID 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1158 AM CDT MON JUL 30 2012
A WEAK STATIONARY FRONT WILL PERSIST ACROSS SOUTHWEST KANSAS THROUGH
TODAY AND TONIGHT. WHILE AN ISOLATED THUNDERSTORM MAY DEVELOP LATE
IN THE AFTERNOON/EVENING ANYWHERE ALONG THIS BOUNDARY...THE COVERAGE
IS NOT EXPECTED TO BE ENOUGH TO JUSTIFY INCLUSION IN THE TAFS. WILL
HOWEVER INCLUDE A PROB30 GROUP FOR THUNDERSTORMS AT GCK DURING THE
OVERNIGHT HOURS AS THERE IS A GREATER PROBABILITY OF A SMALL CLUSTER
OF STORMS TO MOVE EAST OUT OF EASTERN COLORADO AND PERHAPS AFFECT
GCK ALONG/NORTH OF THE MENTIONED STATIONARY FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 72 100 75 104 / 10 10 20 10
GCK 71 96 73 103 / 20 10 20 20
EHA 70 98 73 103 / 30 20 20 20
LBL 71 99 74 104 / 20 10 20 10
HYS 71 98 75 103 / 10 10 20 10
P28 75 104 78 108 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...HOVORKA_42
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1159 AM CDT MON JUL 30 2012
...UPDATED SYNOPSIS AND AVIATION SECTION FOR 18Z TAFS...
.SYNOPSIS...
ISSUED AT 1158 AM CDT MON JUL 30 2012
AN UPPER LEVEL HIGH CONTINUED TO GRIP THE CENTRAL AND SOUTHERN GREAT
PLAINS. THE CENTER OF THE HIGH AT 500MB WAS LOCATED ACROSS THE
SOUTHERN TEXAS PANHANDLE PER RAOB AND RAP ANALYSIS AS OF 30.12Z. AN
ARC OF MID LEVEL MOISTURE COULD BE SEEN ON WATER VAPOR LOOP AND RAOB
ANALYSIS FROM WESTERN/CENTRAL ARIZONA THROUGH UTAH AND NORTHEAST TO
SOUTHEASTERN WYOMING AND WESTERN NEBRASKA. ALL ALONG THIS MOISTURE
ARC...THERE WERE MINOR MID LEVEL PERTURBATIONS IN THE FLOW PATTERN
DUE TO LATENT HEAT RELEASE FROM VARIOUS THUNDERSTORM CLUSTERS. A
MESOSCALE CONVECTIVE SYSTEM MOVED ACROSS SOUTHERN NEBRASKA/NORTHERN
KANSAS DURING THE OVERNIGHT HOURS WITH THE MID LEVEL POTENTIAL
VORTICITY ANOMALY TIED TO THIS MCS MOVING INTO EASTERN KS/WESTERN
MO. ADDITIONAL MID LEVEL VORTICITY COULD BE SEEN IN THE RAP ANALYSIS
MOVING INTO NORTHERN COLORADO WITH A 30-40 KNOT 400MB SPEED MAX
ROTATING NORTH-NORTHEASTWARD INTO THE COLORADO ROCKIES. IN THE LOWER
TROPOSPHERE...A STATIONARY FRONT EXTENDED FROM ROUGHLY BEAVER, OK TO
BUCKLIN, KS TO NEAR PRATT, KS AT 16Z. OKLAHOMA MESONET OBSERVATIONS
AT 1650Z REVEALED AN AXIS OF 102 TO 104F TEMPERATURES ACROSS
WEST-CENTRAL OKLAHOMA ON WEST-SOUTHWEST SURFACE WINDS SOUTH OF THIS
BOUNDARY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CDT MON JUL 30 2012
TODAY INTO TONIGHT WILL SEE THE MID/UPPER LEVEL PATTERN CHANGE
LITTLE AS A STRONG HIGH ANCHORS ACROSS THE CENTRAL/SOUTHERN HIGH
PLAINS WHILE A MODEST 70-80 KNOT UPPER JET SLIPS ACROSS THE DAKOTAS.
A MONSOONAL SUBTROPICAL MOISTURE PLUME WRAPPING AROUND THE BACK SIDE
OF THIS HIGH WILL CONTINUE TO STRETCH FROM THE DESERT SOUTHWEST INTO
THE CENTRAL HIGH PLAINS REGION WITH CONVECTION POSSIBLE ANYWHERE IN
THIS PLUME. NONETHELESS...THE DIRECT CIRCULATION ASSOCIATED WITH THE
ENTRANCE REGION OF THIS JET STREAK ALONG WITH OUTFLOW FROM
CONVECTION THIS PAST EVENING TO OVERNIGHT IS PUSHING A WEAK
FRONT/CONVECTIVE OUTFLOW INTO SOUTHWEST KANSAS THIS MORNING. THIS
BOUNDARY AND ITS POSITIONING LEADS TO SEVERAL QUESTIONS FOR THE
AFTERNOON TO EVENING HOURS.
INITIALLY FOR THE MORNING HOURS...THIS SETUP WILL ONLY RESULT IN A
WIND SHIFT FOR LOCATIONS MOSTLY NORTH OF HIGHWAY 50 AS THE BOUNDARY
SLOWS TO A STALL WHILE CONVECTION REMAINS NEAR THE NEBRASKA BORDER.
HOWEVER...AS THE MORNING GIVES WAY TO THE AFTERNOON HOURS...DEEP
THERMAL MIXING AND ASSOCIATED MOMENTUM TRANSFER FROM WINDS ALOFT MAY
MIX OUT THE SOUTHERN PERIPHERY OF THE BOUNDARY. NONETHELESS...THE
RAP MODEL HINTS AT A SMALL FRONTAL WAVE MOVING OVER SOUTHERN
KANSAS THAT COUNTERS ANY NORTHWARD MOVEMENT OF THE BOUNDARY. THIS
SETS UP A COMPLICATED HIGH TEMPERATURE SCENARIO BASED ON BOUNDARY
LOCATION. LOCATIONS SOUTH OF THE BOUNDARY WILL LIKELY SEE
TEMPERATURES A FEW DEGREES EITHER SIDE OF 105 AS THERMAL MIXING
EXPANDS TO LEVELS AT OR ABOVE 700 HPA WHERE TEMPERATURES OF +14 TO
+16C EXIST. NORTH OF THE BOUNDARY...HIGHS REALISTICALLY COULD
VARYING FROM 95 TO AROUND 100. GUESS AT THIS POINT IS FOR THE
DIVIDING LINE TO REMAIN ROUGHLY ALONG A HIGHWAY 56 LINE BUT THIS
WILL LIKELY NEED ADJUSTING THROUGH THE DAY. ALTHOUGH HEAT INDEX
VALUES WILL APPROACH ADVISORY LEVELS BY MID AFTERNOON SOUTH OF THE
BOUNDARY...THE SAME DEEP THERMAL MIXING BRINGING TEMPS AROUND 105
SHOULD AID IN LOWERING DEWPOINTS ENOUGH TO SUPPRESS HEAT INDEX
VALUES BELOW 105 FOR MOST OF THE DAY.
ATTENTION THEN TURNS TOWARD LATER THIS AFTERNOON TO EARLY EVENING ALONG
AND NORTH OF HIGHWAY 50. ALTHOUGH UPPER SUPPORT WILL BE
MARGINAL...MINIMAL INHIBITION DUE TO CONVECTIVE TEMPS BEING REACHED
AND A DEEP MONSOONAL MOISTURE PROFILE MAY TRIGGER ISOLATED
CONVECTION NORTH OF A GARDEN CITY TO ST JOHN LINE. SHEAR PROFILES
ALONG AND NORTH OF THE BOUNDARY WILL BE MODEST WITH 0-6KM BULK SHEAR
VALUES AROUND 25 TO 30 KNOTS WHILE ML CAPE VALUES ARE AROUND 1000
J/KG. BASED ON THIS SCENARIO...AN ISOLATED STRONG TO SEVERE
STORM CAPABLE OF PRODUCING WIND GUSTS UP TO 60 MPH AND QUARTER SIZE
HAIL CAN/T BE RULED OUT...ESPECIALLY WITH VEERING WINDS ABOVE 6 KM.
OTHERWISE...CONVECTION COMING OFF THE RATON MESA REGION IN COLORADO
MAY SLIP INTO FAR WESTERN KANSAS DURING THE EVENING HOURS BEFORE
FADING BY THE EARLY OVERNIGHT HOURS. OVERNIGHT LOWS WILL REMAIN
WARM WITH READINGS IN THE 70S LIKELY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 AM CDT MON JUL 30 2012
.MONDAY NIGHT THROUGH THURSDAY...
THE LARGE UPPER LEVEL HIGH WILL BE THE MAIN FEATURE DURING THE
EXTENDED FORECAST AND BE LOCATED ACROSS THE CENTRAL PART OF THE
UNITED STATES WITH AN UPPER LEVEL LONG WAVE TROUGH POSITIONED ACROSS
THE EASTERN CONUS. A PERSISTENT FRONTAL BOUNDARY AT THE SURFACE WILL
BE LOCATED ACROSS WEST CENTRAL AND CENTRAL KANSAS WHICH WILL BE THE
MAIN AREA WHERE CONVECTION COULD OCCUR DURING THE AFTERNOON AND
EVENING HOURS. OTHERWISE EXPECT PARTLY CLOUDY SKIES ACROSS WESTERN
KANSAS. VERY WARM CONDITIONS WILL CONTINUE DURING THIS TIME FRAME
WITH HIGHS RANGING FROM AROUND 100 TO 110 WITH LOWS ONLY DIPPING
INTO THE LOWER TO MID 70S.
.THURSDAY NIGHT THROUGH SATURDAY...
THE AFOREMENTIONED UPPER LEVEL HIGH WILL BE PUSHED SOUTHWARD AS A
STRONG UPPER LEVEL LOW MOVES ACROSS THE NORTHERN PLAINS AND CENTRAL
CANADA. THIS FEATURE WILL HELP PUSH A SECOND FRONT DOWN THROUGH
WESTERN KANSAS. RAIN CHANCES WILL INCREASE ACROSS AS THIS COLD FRONT
MOVES THROUGH THE AREA BUT I HAVE KEPT POPS LOW DUE TO THE
UNCERTAINTY OF SPEED AND INTENSITY OF THIS SYSTEM. THIS FRONT SHOULD
ALLOW TEMPERATURES TO DECREASE SLIGHTLY WITH HIGHS RANGING FROM THE
UPPER 90S TO 103 DEGREES AND LOWS IN THE LOWER TO MID 70S.
.SATURDAY NIGHT THROUGH SUNDAY NIGHT...
THE WEATHER PATTERN BECOMES MORE UNCERTAIN SATURDAY NIGHT THROUGH
SUNDAY AS THE GFS KEEPS THE UPPER LEVEL HIGH ACROSS THE SOUTHERN
ROCKIES AND THE ECMWF REBUILDS THE HIGH OVER THE CENTRAL PLAINS.
NEVERTHELESS, BOTH SOLUTIONS WILL BRING PARTLY CLOUDY SKIES AND DRY
CONDITIONS ACROSS WESTERN KANSAS. HIGHS THROUGH THIS TIME FRAME WILL
GENERALLY BE AROUND 100 DEGREES WITH LOWS REMAINING IN THE LOWER TO
MID 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1158 AM CDT MON JUL 30 2012
A WEAK STATIONARY FRONT WILL PERSIST ACROSS SOUTHWEST KANSAS THROUGH
TODAY AND TONIGHT. WHILE AN ISOLATED THUNDERSTORM MAY DEVELOP LATE
IN THE AFTERNOON/EVENING ANYWHERE ALONG THIS BOUNDARY...THE COVERAGE
IS NOT EXPECTED TO BE ENOUGH TO JUSTIFY INCLUSION IN THE TAFS. WILL
HOWEVER INCLUDE A PROB30 GROUP FOR THUNDERSTORMS AT GCK DURING THE
OVERNIGHT HOURS AS THERE IS A GREATER PROBABILITY OF A SMALL CLUSTER
OF STORMS TO MOVE EAST OUT OF EASTERN COLORADO AND PERHAPS AFFECT
GCK ALONG/NORTH OF THE MENTIONED STATIONARY FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 101 72 105 75 / 20 20 20 20
GCK 99 71 102 73 / 20 20 20 20
EHA 99 70 102 73 / 20 30 20 20
LBL 101 71 104 74 / 10 20 20 20
HYS 99 71 101 75 / 10 20 20 20
P28 108 75 107 78 / 10 10 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...AJOHNSON
LONG TERM...HOVORKA_42
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1145 PM MDT SUN JUL 29 2012
.UPDATE...
ISSUED AT 1140 PM MDT SUN JUL 29 2012
UPDATED SHORT-TERM GRIDS TO REMOVE MENTION OF PRECIP FROM SOUTHERN
PORTIONS OF THE FORECAST AREA BASED ON LATEST RADAR TRENDS. ALSO
INCREASED POPS ALONG AND NORTH OF THE HIGHWAY 36 CORRIDOR FOR THE
NEXT FEW HOURS. LOWERED MINS ACROSS THE WESTERN PORTIONS OF THE
AREA A FEW DEGREES AS WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY AFTERNOON)
ISSUED AT 120 PM MDT SUN JUL 29 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE CONTINUING TO
DOMINATE US PATTERN WITH CENTER OVER NORTHERN TEXAS. ALONG THE
WEST/NORTHWEST EXTENT OF THE RIDGE MONSOONAL MOISTURE CONTINUES TO
STREAM NORTH ACROSS THE INTER-MOUNTAIN WEST TOWARDS THE CWA. AT THE
SURFACE A LINGERING BAROCLINIC ZONE/DECAYED STATIONARY FRONT REMAINS
IN PLACE OVER THE CWA.
EARLY MORNING SHOWERS HAVE MOVED OFF TO THE EAST...WITH CLEARING
OCCURRING TO THE SOUTH AND WEST. MIXED LAYER CAPE VALUES ACROSS THE
AREA ARE CURRENTLY IN THE 500-1500 J/KG RANGE AND SHOULD INCREASE
WITH CLEARING AS LOW LEVEL LAPSE RATES STEEPEN. A WEAK SHORTWAVE
TROUGH IS PROGGED TO MOVE ACROSS SW NEBRASKA...AND MAY BE THE
FEATURE THAT HELPS GET THINGS GOING AGAIN TONIGHT. THE LATEST HRRR
WOULD INDICATE THAT THUNDERSTORM REDEVELOPMENT LIKELY WILL HOLD OFF
UNTIL AFTER 00Z...HOWEVER IT IS DEVELOPING WIDESPREAD CONVECTION
FURTHER SOUTH THAN WHAT THE LATEST NAM/GFS WOULD INDICATE...SO HAVE
KEPT POPS IN CHANCE CATEGORY THIS EVENING/OVERNIGHT. OVERALL SHEAR
IS WEAK AND THERE IS VERY LITTLE TO GET STORMS MOVING IN PROXIMITY
TO BAROCLINIC ZONE. WITH VERY HIGH PWAT VALUES IN EXCESS OF 1.5
HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE WITH THESE SLOW
MOVING THUNDERSTORMS. AS WITH YESTERDAY COVERAGE IS STILL A
QUESTION...WITH BEST COVERAGE RIGHT NOW EXPECTED TO BE ACROSS THE
NORTHERN HALF OTHER CWA OVERNIGHT IN PROXIMITY TO SHORTWAVE TROUGH.
WITH BAROCLINIC ZONE IN PLACE THROUGH MONDAY SHOWERS/THUNDERSTORMS
COULDN`T BE RULED OUT THROUGH MONDAY AFTERNOON AS WEAK PULSES
CONTINUE TO MOVE WITHIN PROXIMITY OF THE CWA.
TEMPERATURES SHOULD BE COOLER ON MONDAY AFTERNOON HIGHS IN THE MID
TO UPPER 90S ACROSS THE CWA. EASTERLY FLOW WILL DEVELOP ACROSS THE
REGION...AND H85 TEMPS WILL MODERATE SOME WITH VALUES ABOUT 3C COOLER.
DEPENDING ON CLOUD COVER SOME LOCATIONS COULD SEE HIGHS ON MONDAY
CLOSER TO NORMAL VALUES IN THE LOW 90S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 205 PM MDT SUN JUL 29 2012
RIDGE OVER THE SOUTHERN PLAINS WILL DRIFT WESTWARD. TEMPERATURES
WILL CONTINUE TO BE ABOVE NORMAL. THE RIDGE IS FAR ENOUGH SOUTH
THAT SHORTWAVE TROUGHS COMING OVER THE TOP WILL BRING OCCASIONAL
CHANCES FOR THUNDERSTORMS. MODELS HINTING AT FAIRLY STRONG ONE
TUESDAY NIGHT WITH POSSIBLE MCS DEVELOPING IN EASTERN COLORADO AND
MOVING ACROSS THE FORECAST AREA. BUMPED POPS UP TO
CHANCE...ESPECIALLY IN THE WEST. THE PATTERN BASICALLY REPEATS
THROUGH THE END OF THE WEEK...SO COULD END UP WITH A RATHER WET
PATTERN. STRONG SYSTEM WILL MOVE ACROSS THE NORTHERN PLAINS ON
FRIDAY AND DRIVE A COLD FRONT THROUGH THE AREA. COOLER
TEMPERATURES FOLLOW ON SATURDAY...AT LEAST CLOSER TO NORMAL.
DESPITE THE POST FRONTAL UPSLOPE AT THE SURFACE...SHORTWAVE
RIDGING IS FORECAST OVER THE WEEKEND...SO THINK PRECIPITATION
CHANCES WILL COME TO AN END.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM MDT SUN JUL 29 2012
PERIODIC MVFR/IFR VISBY CONTINUES AT KMCK WITH A COMPLEX OF
SHOWERS AND THUNDERSTORMS CONTINUING TO IMPACT THE TERMINAL.
APPEARS CONDITIONS WILL BE VARIABLE BETWEEN MVFR/IFR AND VFR FOR
THE NEXT FEW HOURS BEFORE VFR CONDITIONS BECOME ESTABLISHED AROUND
09Z. PRECIP CHANCES HAVE ESSENTIALLY ENDED FOR KGLD FOR THE NIGHT
WITH GUSTY NORTHERLY WINDS UP TO AROUND 30KTS CONTINUING FOR THE
NEXT FEW HOURS IN THE WAKE OF THE CONVECTIVE ACTIVITY FURTHER
NORTH. WINDS DURING THE DAY MONDAY WILL VEER TO THE NORTHEAST/EAST
WITH GUSTS AROUND 20KTS POSSIBLE. STILL CAN`T RULE OUT CONVECTION
MONDAY AFTERNOON AND EVENING BUT SIGNAL IS STILL NOT STRONG
ENOUGH TO WARRANT INCLUSION.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...FOLTZ
SHORT TERM...DR
LONG TERM...024
AVIATION...FOLTZ
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
1153 PM EDT TUE JUL 31 2012
.SYNOPSIS...
LOW PRESSURE ALOFT AND A WARM AND HUMID AIRMASS WILL PERSIST
ALONG THE EASTERN SEABOARD THIS WEEK. A WEAK COLD FRONT WILL
APPROACH THE MID-ATLANTIC REGION ON WEDNESDAY. A SECOND FRONTAL
BOUNDARY IS EXPECTED TO CROSS THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BROKEN LINE OF THUNDERSTORMS CONTINUE TO DROP SOUTHEAST THROUGH
CENTRAL VIRGINIA. MUCAPE OVER EASTERN LWX CWA IS STILL 1500 TO
2000 J/KG ACCORDING TO RAP MODEL ON SPC MESO PAGE. STRATIFORM
APPROACHING DC MAY BE ALL THE METRO AREA GETS. HOWEVER...THE
SCATTERED THUNDERSTORMS THAT DEVELOPED OVER THE PAST HALF HOUR
EAST OF BALTIMORE IS INDICATIVE OF THE REMNANT INSTABILITY.
THROUGH THE MIDNIGHT HOUR ACTIVITY IS THE MAIN FEATURE
TONIGHT...WITH ONLY ISOLATED ACTIVITY AT BEST AFTERWARDS. EXPECT
AT LEAST PATCHY FOG IN THE WAKE OF THE THUNDERSTORMS.
WITH STAGNANT AMS...CU FIELD SHOULD DVLP QUICKLY AGAIN WED MRNG.
SHWRS AND TSTMS ONCE AGAIN CAN BE XPCD DURG THE DAY ON WED WITH
TROF RMNG ALONG APLCNS AND WEAK CDFNT APRCHG RGN. THERE IS SOME
UNCERTAINTY AS TO THE SWD ADVCMT OF THE BNDRY DURG THE DAY...SO
POPS WERE FOCUSED IN NWRN PORTION OF FCST AREA. MAXIMA IN MID-UPR
80S XPCD.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
UPPER-LEVEL AND SFC TROUGH WILL MOVE OFFSHORE THU...ALLOWING THE
MID-ATLC TO DRY OUT FOR A COUPLE OF DAYS. OUTSIDE OF A WEAK SFC
TROUGH THAT WILL DRIFT OVER THE AREA LATE THU INTO FRI...THE AREA
SHOULD BE FAIRLY QUIET. THIS WILL ALLOW FOR A BIT OF A WARM-UP
BOTH DAYS... ESPECIALLY FRI. HUMIDITY VALUES WILL NOT CHALLENGE
SOME OF THE HOTTER VALUES THIS YEAR...BUT TEMPS AND HEAT INDICES
WILL APPROACH THE M90S EACH AFTN.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE MAIN STORY FOR NEXT WEEKEND WILL BE THE BUILD-UP TO A FRONTAL
PASSAGE ON MONDAY. A POTENT LOW PRESSURE SYSTEM WILL SWING DOWN FROM
THE CANADIAN ROCKIES LATE THIS WEEK...DRAGGING ALONG THE US/CANADA
BORDER THIS WEEKEND. AS THE SYSTEM APPROACHES...A LARGE BERMUDA HIGH
WILL CREATE A FETCH OF WARM-MOIST AIR UP THE EASTERN SEABOARD BOTH
SAT AND SUN. SHOWERS AND TSTMS OF AN ISOLATED NATURE WILL BE
POSSIBLE EACH DAY THIS WEEKEND...ALONG WITH HIGHS IN THE L90S HIGHER
HUMIDITY THAN IN PAST DAYS.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
PRECIP WITH LOW CHANCES FOR IFR CONTINUES TO PUSH THROUGH THE
BALT-WASH METRO. THEN AN OVNGT LULL IN PCPN XPCD. ALTHOUGH LOW
CIG DVLPMT IS VERY UNCERTAIN TNGT...FOG IS A PSBLTY OWING TO CONTD
HIGH DEWPT TEMPS. SHWRS AND TSTMS LKLY TO DVLP AGAIN ON WED.
A COUPLE OF DRY DAYS TO CLOSE OUT THE WORK WEEK...AS HIGH PRESSURE
BRIEFLY BUILDS IN ACROSS THE REGION. THE WEEKEND WILL SEE THE RETURN
OF MOISTURE AND CUMULUS FIELD...ALONG WITH ISOLATED TSTMS. A LOW
PRESSURE SYSTEM APPROACHES FROM THE GREAT LAKES THIS WEEKEND...
DRAGGING A COLD FRONT ACROSS THE AREA ON MONDAY.
&&
.MARINE...
ISOLATED THUNDERSTORMS EXPECTED ACROSS THE WATERS THROUGH 2AM.
ADDITIONAL SPECIAL MARINE WARNINGS ARE POSSIBLE. SLY FLOW WILL
CONTINUE TO GUST AROUND 15 KT THROUGH WEDNESDAY.
GENERALLY LIGHT SLY WINDS LATE THIS WEEK INTO THE WEEKEND...THOUGH
SLY CHANNELING WILL OCCUR EACH AFTN/EVE. A COLD FRONT WILL THEN
MOVE ACROSS THE AREA LATE MON INTO TUE OF NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...JACKSON
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1003 PM EDT TUE JUL 31 2012
.SYNOPSIS...
LOW PRESSURE ALOFT AND A WARM AND HUMID AIRMASS WILL PERSIST
ALONG THE EASTERN SEABOARD THIS WEEK. A WEAK COLD FRONT WILL
APPROACH THE MID-ATLANTIC REGION ON WEDNESDAY. A SECOND FRONTAL
BOUNDARY IS EXPECTED TO CROSS THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BROKEN LINE OF THUNDERSTORMS CONTINUES TO MOVE EAST FROM THE
SHENANDOAH VALLEY ACROSS THE BLUE RIDGE. MUCAPE AHEAD OF THIS LINE
IS ON THE ORDER OF 1500 TO 2500 J/KG ACCORDING TO RAP MODEL ON SPC
MESO PAGE. A MODIFIED 00Z SOUNDING FOR INCREASED LLVL MOISTURE
/DEWPOINTS HAVE RISEN AT KIAD FROM THE LOW 60S LATE THIS AFTERNOON
TO THE LOW 70S AS OF 01Z/. EXPECT SCATTERED THUNDERSTORMS TO
CONTINUE MOVING EAST THROUGH THE MIDNIGHT HOUR SOUTH OF
DC...ISOLATED ACROSS THE BALT-WASH METRO AS INDICATED BY THE
ACTIVITY NEAR HAGERSTOWN AND SRN FREDERICK CO MD. SOMEWHAT
FREQUENT LIGHTNING CONTINUES WITH THIS ACTIVITY SO EXPECT RUMBLES
OF THUNDER. THE ACTIVITY IS MOVING QUITE SLOWLY...10 TO 15
MPH...SO ISOLATED FLASH FLOODING WILL REMAIN A THREAT. HWO WILL BE
UPDATED ACCORDINGLY.
THIS LATE EVENING/MIDNIGHT HOUR ACTIVITY IS THE MAIN FEATURE
TONIGHT...WITH ONLY ISOLATED ACTIVITY AT BEST AFTERWARDS. EXPECT
AT LEAST PATCHY FOG IN THE WAKE OF THE THUNDERSTORMS.
WITH STAGNANT AMS...CU FIELD SHOULD DVLP QUICKLY AGAIN WED MRNG.
SHWRS AND TSTMS ONCE AGAIN CAN BE XPCD DURG THE DAY ON WED WITH
TROF RMNG ALONG APLCNS AND WEAK CDFNT APRCHG RGN. THERE IS SOME
UNCERTAINTY AS TO THE SWD ADVCMT OF THE BNDRY DURG THE DAY...SO
POPS WERE FOCUSED IN NWRN PORTION OF FCST AREA. MAXIMA IN MID-UPR
80S XPCD.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
UPPER-LEVEL AND SFC TROUGH WILL MOVE OFFSHORE THU...ALLOWING THE
MID-ATLC TO DRY OUT FOR A COUPLE OF DAYS. OUTSIDE OF A WEAK SFC
TROUGH THAT WILL DRIFT OVER THE AREA LATE THU INTO FRI...THE AREA
SHOULD BE FAIRLY QUIET. THIS WILL ALLOW FOR A BIT OF A WARM-UP
BOTH DAYS... ESPECIALLY FRI. HUMIDITY VALUES WILL NOT CHALLENGE
SOME OF THE HOTTER VALUES THIS YEAR...BUT TEMPS AND HEAT INDICES
WILL APPROACH THE M90S EACH AFTN.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE MAIN STORY FOR NEXT WEEKEND WILL BE THE BUILD-UP TO A FRONTAL
PASSAGE ON MONDAY. A POTENT LOW PRESSURE SYSTEM WILL SWING DOWN FROM
THE CANADIAN ROCKIES LATE THIS WEEK...DRAGGING ALONG THE US/CANADA
BORDER THIS WEEKEND. AS THE SYSTEM APPROACHES...A LARGE BERMUDA HIGH
WILL CREATE A FETCH OF WARM-MOIST AIR UP THE EASTERN SEABOARD BOTH
SAT AND SUN. SHOWERS AND TSTMS OF AN ISOLATED NATURE WILL BE
POSSIBLE EACH DAY THIS WEEKEND...ALONG WITH HIGHS IN THE L90S HIGHER
HUMIDITY THAN IN PAST DAYS.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
SCATTERED HEAVY THUNDERSTORMS CROSS THE TERMINALS THROUGH THE
MIDNIGHT HOUR. THEN AN OVNGT LULL IN PCPN XPCD. ALTHOUGH LOW CIG
DVLPMT IS VERY UNCERTAIN TNGT...FOG IS A PSBLTY OWING TO CONTD
HIGH DEWPT TEMPS. SHWRS AND TSTMS LKLY TO DVLP AGAIN ON WED.
A COUPLE OF DRY DAYS TO CLOSE OUT THE WORK WEEK...AS HIGH PRESSURE
BRIEFLY BUILDS IN ACROSS THE REGION. THE WEEKEND WILL SEE THE RETURN
OF MOISTURE AND CUMULUS FIELD...ALONG WITH ISOLATED TSTMS. A LOW
PRESSURE SYSTEM APPROACHES FROM THE GREAT LAKES THIS WEEKEND...
DRAGGING A COLD FRONT ACROSS THE AREA ON MONDAY.
&&
.MARINE...
SCATTERED THUNDERSTORMS EXPECT ACROSS THE WATERS 11PM TO 2AM.
SPECIAL MARINE WARNINGS ARE POSSIBLE. SLY FLOW WILL CONTINUE TO
GUST AROUND 15 KT THROUGH WEDNESDAY.
GENERALLY LIGHT SLY WINDS LATE THIS WEEK INTO THE WEEKEND...THOUGH
SLY CHANNELING WILL OCCUR EACH AFTN/EVE. A COLD FRONT WILL THEN
MOVE ACROSS THE AREA LATE MON INTO TUE OF NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...JACKSON
PREVIOUS DISCUSSION...KRAMAR/GMS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
304 PM EDT MON JUL 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE A WARM SUMMER AFTERNOON EVENING. INCREASING
HUMIDITY AND A SLOW EASTBOUND LOW PRESSURE SYSTEM WILL FUEL
SCATTERED SHOWERS AND THUNDERSTORMS TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
RECENT SATELLITE SATELLITE DATA AND RAP MODEL OUTPUT SHOW SOME
CUMULUS BUILD UPS WITHIN THE UPPER OHIO VALLEY, CONFINED TO AREAS
JUST SOUTH OF LAKE ERIE OR NEAR THE APPALACHIAN MOUNTAINS. RAP
MODEL OUTPUT SUGGESTS SLIGHTLY INCREASED INSTABILITY IN THESE
LOCATIONS, WHERE EITHER H8 TEMPERATURES ARE SLIGHTLY WARMER OR H5
TEMPERATURES ARE SLIGHTLY COLDER. RECENT SURFACE DATA CONTINUES TO
SHOW NO MORE THAN SEASONABLE HUMIDITY VALUES ACROSS THE UPPER OHIO
VALLEY, SO INSTABILITY OF THE LIFTED PARCELS MAY BE RESTRICTED BY
DRY AIR ENTRAINMENT. HENCE HAVE MAINTAINED NO MORE THAN A SLIGHT
CHANCE OF THUNDERSTORMS NEAR THE MOUNTAINS DUE TO OROGRAPHIC
ENHANCEMENT.
SOUTHERLY LOW LEVEL WINDS WILL INCREASE HUMIDITY VALUES OVERNIGHT
AND TUESDAY. WHILE RECENT SREF MODEL OUTPUT CONTINUES TO SHOW A
LOW PRESSURE TROUGH WILL MOVE SLOWLY SOUTHEASTWARD THROUGH THE
GREAT LAKES. SO EXPECT MORE OF A CHANCE OF THUNDERSTORMS BY
TUESDAY AFTERNOON AS DAYTIME HEATING INCREASES THE INSTABILITY AND
PRE-SYSTEM CONVERGENCE INCREASES LIFT AND STORM ORGANIZATION.
CONCUR WITH SPC THAT THE RISK OF SEVERE REMAINS RESTRICTED DUE TO
WEAK VERTICAL SHEAR. LIKEWISE, THUNDERSTORM RAINFALL MAY BE
RESTRICTED, AS HUMIDITY VALUES DO NOT APPEAR EXTRAORDINARILY LARGE
NOR STORM MOVEMENTS EXTRAORDINARILY SLOW.
FORECASTED TEMPERATURES A COUPLE DEGREES WARMER THAN NORMAL USING
BLEND OF RECENT GFS AND NAM MOS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW THE LIFT-PRODUCING LOW
PRESSURE TROUGH EXITING EAST PAST THE APPALACHIAN MOUNTAINS
DAYTIME WEDNESDAY. SO HAVE MAINTAINED A CHANCE OF SHOWERS AND
THUNDERSTORMS TUESDAY NIGHT, WITH CHANCES TRENDING LOWER WEST TO
EAST ACROSS THE UPPER OHIO VALLEY WEDNESDAY. THIS IS DESPITE
HUMIDITY VALUES REMAINING ABOVE NORMAL, WITH SURFACE DEW POINTS IN
THE MID 60S, INTO THURSDAY.
BASED ON RECENT GFS, NAM, AND ECMWF MOS, FORECASTED TEMPERATURE
GENERALLY ABOUT 5 DEGREES WARMER THAN NORMAL EACH PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
SLIGHTLY UNSETTLED PATTERN FOR THE LONG TERM PORTION OF THE
FORECAST. TRENDED AWAY FROM THE ECMWF...WHICH SEEMED TO HANG A FRONT
OVER THE REGION MUCH LONGER THAN OTHER DETERMINISTIC/ENSEMBLE
MODELS. BEST CHANCE FOR RAIN APPEARS TO BE SUNDAY INTO SUNDAY
NIGHT...WITH SOME TIMING CONSENSUS FOR FRONT FROM GFS/CMC/GEFS.
TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL BEFORE THE FRONTAL
PASSAGE...RETURNING TO NORMAL BY SUNDAY AND MONDAY.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
EXPECT SCATTERED LOW CLOUDS TO REMAIN IN THE FORECAST FOR THE ENTIRE
TAF PERIOD. ALTHOUGH THERE WILL BE SOME ISOLATED SHOWERS/STORMS IN
THE RIDGES...NOT ENOUGH CONFIDENCE THAT PRECIP WILL REACH MGW OR LBE
TO INCLUDE IN TAFS. WINDS WILL GENERALLY BE LIGHT AND OUT OF THE
SOUTHEAST. IF WINDS DO MANAGE TO GO CALM TONIGHT...SOME MVFR
VISIBILITIES CANNOT BE RULED OUT.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
SCATTERED SHOWERS/STORMS ARE MORE LIKELY TUESDAY INTO
WEDNESDAY...WITH GENERALLY DRY CONDITIONS EXPECTED FOR THURSDAY
AND FRIDAY. RESTRICTIONS WILL BE POSSIBLE AGAIN IN SCATTERED
SHOWERS/STORMS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
251 PM EDT MON JUL 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE A WARM SUMMER AFTERNOON EVENING. INCREASING
HUMIDITY AND A SLOW EASTBOUND LOW PRESSURE SYSTEM WILL FUEL
SCATTERED SHOWERS AND THUNDERSTORMS TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
RECENT SATELLITE SATELLITE DATA AND RAP MODEL OUTPUT SHOW SOME
CUMULUS BUILD UPS WITHIN THE UPPER OHIO VALLEY, CONFINED TO AREAS
JUST SOUTH OF LAKE ERIE OR NEAR THE APPALACHIAN MOUNTAINS. RAP
MODEL OUTPUT SUGGESTS SLIGHTLY INCREASED INSTABILITY IN THESE
LOCATIONS, WHERE EITHER H8 TEMPERATURES ARE SLIGHTLY WARMER OR H5
TEMPERATURES ARE SLIGHTLY COLDER. RECENT SURFACE DATA CONTINUES TO
SHOW NO MORE THAN SEASONABLE HUMIDITY VALUES ACROSS THE UPPER OHIO
VALLEY, SO INSTABILITY OF THE LIFTED PARCELS MAY BE RESTRICTED BY
DRY AIR ENTRAINMENT. HENCE HAVE MAINTAINED NO MORE THAN A SLIGHT
CHANCE OF THUNDERSTORMS NEAR THE MOUNTAINS DUE TO OROGRAPHIC
ENHANCEMENT.
SOUTHERLY LOW LEVEL WINDS WILL INCREASE HUMIDITY VALUES OVERNIGHT
AND TUESDAY. WHILE RECENT SREF MODEL OUTPUT CONTINUES TO SHOW A
LOW PRESSURE TROUGH WILL MOVE SLOWLY SOUTHEASTWARD THROUGH THE
GREAT LAKES. SO EXPECT MORE OF A CHANCE OF THUNDERSTORMS BY
TUESDAY AFTERNOON AS DAYTIME HEATING INCREASES THE INSTABILITY AND
PRE-SYSTEM CONVERGENCE INCREASES LIFT AND STORM ORGANIZATION.
CONCUR WITH SPC THAT THE RISK OF SEVERE REMAINS RESTRICTED DUE TO
WEAK VERTICAL SHEAR. LIKEWISE, THUNDERSTORM RAINFALL MAY BE
RESTRICTED, AS HUMIDITY VALUES DO NOT APPEAR EXTRAORDINARILY LARGE
NOR STORM MOVEMENTS EXTRAORDINARILY SLOW.
FORECASTED TEMPERATURES A COUPLE DEGREES WARMER THAN NORMAL USING
BLEND OF RECENT GFS AND NAM MOS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW THE LIFT-PRODUCING LOW
PRESSURE TROUGH EXITING EAST PAST THE APPALACHIAN MOUNTAINS
DAYTIME WEDNESDAY. SO HAVE MAINTAINED A CHANCE OF SHOWERS AND
THUNDERSTORMS TUESDAY NIGHT, WITH CHANCES TRENDING LOWER WEST TO
EAST ACROSS THE UPPER OHIO VALLEY WEDNESDAY. THIS IS DESPITE
HUMIDITY VALUES REMAINING ABOVE NORMAL, WITH SURFACE DEW POINTS IN
THE MID 60S, INTO THURSDAY.
BASED ON RECENT GFS, NAM, AND ECMWF MOS, FORECASTED TEMPERATURE
GENERALLY ABOUT 5 DEGREES WARMER THAN NORMAL EACH PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
SLIGHTLY UNSETTLED PATTERN FOR THE LONG TERM PORTION OF THE
FORECAST. TRENDED AWAY FROM THE ECMWF...WHICH SEEMED TO HANG A FRONT
OVER THE REGION MUCH LONGER THAN OTHER DETERMINISTIC/ENSEMBLE
MODELS. BEST CHANCE FOR RAIN APPEARS TO BE SUNDAY INTO SUNDAY
NIGHT...WITH SOME TIMING CONSENSUS FOR FRONT FROM GFS/CMC/GEFS.
TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL BEFORE THE FRONTAL
PASSAGE...RETURNING TO NORMAL BY SUNDAY AND MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
EXPECT SCATTERED LOW CLOUDS TO REMAIN IN THE FORECAST FOR THE ENTIRE
TAF PERIOD. ALTHOUGH THERE WILL BE SOME ISOLATED SHOWERS/STORMS IN
THE RIDGES...NOT ENOUGH CONFIDENCE THAT PRECIP WILL REACH MGW OR LBE
TO INCLUDE IN TAFS. WINDS WILL GENERALLY BE LIGHT AND OUT OF THE
SOUTHEAST. IF WINDS DO MANAGE TO GO CALM TONIGHT...SOME MVFR
VISIBILITIES CANNOT BE RULED OUT.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
SCATTERED SHOWERS/STORMS ARE MORE LIKELY TUESDAY INTO
WEDNESDAY...WITH GENERALLY DRY CONDITIONS EXPECTED FOR THURSDAY
AND FRIDAY. RESTRICTIONS WILL BE POSSIBLE AGAIN IN SCATTERED
SHOWERS/STORMS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1112 AM EDT MON JUL 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE A WARM SUMMER AFTERNOON. INCREASING
HUMIDITY AND SLOW MOVING LOW PRESSURE ALOFT WILL FUEL SCATTERED
SHOWERS AND THUNDERSTORMS TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
JUDGING FROM BLEND OF RECENT SATELLITE AND UPPER AIR DATA ALONG
WITH HRRR AND WRF-NMM MODEL OUTPUT, EXPECT MOST OF THE UPPER OHIO
VALLEY TO HAVE A WARM AND DRY AFTERNOON.
CANNOT COMPLETELY RULE OUT ISOLATED THUNDERSTORM DEVELOPMENT LATE
THIS AFTERNOON, BUT CONFINED MENTION OF SLIGHT CHANCE TO NEED NEAR
THE WV-MD MOUNTAINS AND PA LAUREL HIGHLANDS.
NEED CONVECTIVE TEMPERATURES OF 83-85F BEFORE CUMULUS BUILD
UPS/TOWERING CUMULUS/ DEVELOP, WHICH COULD HAPPEN 3-4 PM. HOWEVER,
DEEP MOISTURE WILL BE LACKING, SO DRY ENTRAINMENT MAY PREVENT
CUMULONIMBUS, EXCEPT WHERE LIFT AND MOISTURE CONVERGENCE ARE
OROGRAPHICALLY ENHANCED.
AS HUMIDITY INCREASES OVERNIGHT, ITS POSSIBLE THUNDERSTORMS MAY
DEVELOP ACROSS OTHER PARTS OF THE UPPER OHIO VALLEY.
FORECASTED TEMPERATURES A COUPLE DEGREES WARMER THAN NORMAL USING
BLEND OF RECENT GFS AND NAM MOS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
MODELS IN OVERALL AGREEMENT ON THE EASTBOUND PASSAGE OF A SERIES
OF UPPER LEVEL SHORTWAVE TROUGHS THROUGH THE HUMID UPPER OHIO
VALLEY THIS PERIOD. SO HAVE CONTINUED SHOWER AND THUNDERSTORM
CHANCES INTO WEDNESDAY, WITH A CONTINUED DIURNAL TREND FOR HIGHER
AFTERNOON AND EVENING POPS.
BULK OF ACTIVITY SHOULD BE ON THE WANE WEDNESDAY AFTERNOON AS
MODELS IN GENERAL SHIFT DEEPER MOISTURE EAST OF THE RIDGES.
THE SPC SEVERE WEATHER OUTLOOK SHOWS NO MORE THAN A 5 PERCENT
CHANCE OF SEVERE THUNDERSTORMS THIS PERIOD, AS VERTICAL WIND SHEAR
WILL BE WEAK.
AS THE OVERALL FLOW PATTERN FOR THE SHORT TERM IS CLOSE TO THE
SUMMER CLIMATOLOGY...TEMPERATURES SHOULD AVERAGE OUT CLOSE TO THE
SEASONAL NORMALS AND WERE FORECAST USING A BLEND OF GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOW HIGH PRESSURE
PROVIDING MAINLY DRY CONDITIONS ACROSS THE UPPER OHIO VALLEY
THURSDAY AND FRIDAY. THEREAFTER...HAVE FORECASTED A CHANCE OF
THUNDERSTORMS FOR THE WEEKEND...AS SOUTHERLY WIND ON THE WESTERN FLANK
OF THE EXITING HIGH PRESSURE INCREASE HUMIDITY AND INSTABILITY IN
ADVANCE OF EASTBOUND CANADIAN LOW PRESSURE.
FORECASTED TEMPERATURES WILL AVERAGE ABOVE NORMAL BASED ON A
BLEND OF GFS AND ECMWF MOS WITH NAEFS MEDIAN VALUES.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE TERMINALS
THROUGH THE TAF PERIOD. CLOUDS WILL BE ON THE INCREASE INTO THE
EVENING. AT THIS TIME DID NOT INSERT ANY PRECIPITATION BECAUSE OF
LOW PROBABILITY AT TERMINALS. NAM DOES TRY TO BRING IN SCATTERED
SHOWERS MONDAY EVENING BUT GFS HOLDS OFF WITH MORE LIKELY
PROBABILITY ON TUESDAY. WENT WITH GFS SOLUTION AND HELD OFF ANY
PRECIP. WINDS SHOULD NOT BE A PROBLEM COMING FROM THE SE AND S BY
LATE IN THE DAY AND WILL ALL BE BELOW 10KTS.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
A WEAK FRONTAL SYSTEM WILL BE PUSHING EAST FROM THE MIDWEST AND
WILL TRIGGER SOME SCATTERED SHOWERS AND THUNDERSTORMS ESPECIALLY
BY TUESDAY AFTERNOON. SOME SCATTERED SHOWERS AND STORMS COULD
LINGER INTO WEDNESDAY AND THEN HIGH PRESSURE WILL MOVE EAST FOR
THURSDAY AND MOST OF FRIDAY WITH VFR CONDITIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
113 PM EDT MON JUL 30 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 443 AM EDT MON JUL 30 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN GENERAL TROFFING CENTERED NEAR HUDSON BAY AND
PERSISTENT RDG AXIS OVER THE HI PLAINS. WITH LOSS OF DAYTIME
HEATING...SHRA/TS THAT IMPACTED THE CWA LAST EVNG HAVE DIMINISHED.
BUT ANOTHER LINE OF SHRA/TS IS PUSHING SEWD THRU THE MN ARROWHEAD IN
ADVANCE OF POTENT SHRTWV MOVING ESEWD IN MANITOBA TOWARD NW MN AND
LEFT EXIT OF SUPPORTING 75KT H3 JET MAX NOTED IN THE NRN PLAINS.
THIS LINE OF TS PROMPTED THE ISSUANCE OF A WATCH FOR MUCH OF NE
MN...WITH SOME SVR TS GIVEN STEEP MID LVL LAPSE RATES SHOWN ON THE
00Z INL RAOB THAT CONTRIBUTED TO MUCAPE IN EXCESS OF 2000 J/KG AS
WELL AS EFFECTIVE DEEP LYR SHEAR UP TO 40KTS UNDER UNIDIRECTIONAL
WNW FLOW ALF PER SPC ANALYSIS. PRESENCE OF DRIER AIR ALF SHOWN ON
00Z RAOBS HAS CONTRIBUTED TO DCAPE AOA 1000 J/KG IN PORTIONS OF THE
AREA IMPACTED BY THE WATCH. RECENT TRENDS HOWEVER ARE FOR THE STORMS
TO WEAKEN AS THEY MOVE INTO A BIT MORE STABLE AIR IMPACTED BY
NOCTURNAL COOLING AND AXIS OF LOWER H85 DEWPTS OVER CENTRAL MN.
MAIN FCST CONCERNS THIS PACKAGE INCLUDE CONVECTIVE TRENDS INTO TNGT
AND POTENTIAL FOR SVR STORMS.
TODAY...VIGOROUS SHRTWV TO THE NW IS PROGGED TO MOVE TO JUST N OF
INL AT 12Z MON AND THEN INTO FAR NE LK SUP BY 00Z TUE WITH SWATH OF
VIGOROUS DVPA/DEEP LYR QVECTOR CNVGC MOVING W-E ACRS UPR MI.
ALTHOUGH AXIS OF LOWER H85 THETA E CONTRIBUTING TO WEAKENING STORMS
IN MN NOW MAY TEND TO REDUCE COVERAGE/INTENSITY THIS MRNG...ONSET OF
DAYTIME HEATING AND ARRIVAL OF MORE IMPRESSIVE H85 THETA E ADVECTION
BY THIS AFTN IN PRESENCE OF THE HEFTY DYNAMICS SHOULD LEAD TO NMRS
SHRA/TS...ESPECIALLY OVER THE CNTRL AND E WHERE ARRIVAL OF DYNAMICS
APPEAR TO BE MOST IN SYNC WITH DAYTIME HEATING. NAM/GFS FCST SNDGS
INDICATE SBCAPE WL REACH AOA 2000 J/KG AS HI TEMPS RISE WELL INTO
THE 80S AWAY FM LK MODERATION MOST PRONOUNCED OFF LK MI. DRYING ALF
UNDER UNIDIRECTIONAL WNW FLOW ON THE SRN FLANK OF SHRTWV TRACK IS
FCST TO CONTRIBUTE TO SFC-10K FT AGL DELTA THETA E UP TO 25C...VERY
FAVORABLE PER THE MQT SEVERE WX CHECKLIST TO ENHANCE DCAPE. THE
BIGGEST DRAWBACK FOR ORGANIZED SEVERE WX IS FCST RATHER MODEST DEEP
LYR SHEAR ONLY 25-30KTS. THIS WEAKER SHEAR MAY RESULT IN MORE PULSE
SVR EPISODES...WITH THE BETTER CHC FOR ORGANIZED STORMS WHERE LK
BREEZE CNVGC OVER MAINLY THE E HALF MIGHT ENHANCE THE SHEAR AS WELL
AS INCRS LLVL CNVGC AND SHRA/TS COVERAGE. SHRA/TS WL DIMINISH OVER
THE W IN THE AFTN WITH ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/LLVL
DRYING IN THE WAKE OF SHRTWV PASSAGE/ATTENDANT COLD FROPA.
TNGT...DRYING/NEGATIVE H85 THETA E ADVECTION IN THE WAKE OF SHRTWV
MOVING INTO SE ONTARIO AND LOSS OF DAYTIME HEATING WL CAUSE SHRA/TS
TO DIMINISH NW-SE. HOWEVER...MODELS SHOW QUITE A BIT OF LINGERING
LLVL MSTR WITH NNW FLOW IN THE WAKE OF DEPARTING SHRTWV/SFC LO. LO
CLDS MAY BE ESPECIALLY TENACIOUS IN THE UPSLOPE AREAS NEAR LK SUP...
WHERE THERE MAY EVEN BE SOME -DZ/SPRINKLES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 443 AM EDT MON JUL 30 2012
VERY ACTIVE FORECAST PERIOD...AS UPPER MI SITS IN AN UPPER LEVEL
TROUGHING PATTERN THROUGH TUESDAY...BEFORE STRONG RIDGING PATTERN
OVER MUCH OF THE CONUS BEGINS TO MOVE EASTWARD INTO THE REGION.
ALONG THIS RIDGE...SEVERAL SHORTWAVES WILL PASS OVER UPPER MI
BRINGING CHANCES FOR TSRA WED AND THUR AND THEN AGAIN DURING THE
WEEKEND.
AFTER EXITING 500MB SHORTWAVE DURING THE DAY TUESDAY...STRONG
RIDGING WILL BEGIN TO PUSH IN FROM WEST TO EAST...WHICH WILL ALSO
TRANSLATE TO SURFACE HIGH PRESSURE. AS WINDS TURN TO A NORTHERLY
DIRECTION...EXPECT AN INFLUX OF DRY AIR AND CLEARING SKIES ACROSS
THE REGION. SUCH A WIND DIRECTION WILL CAUSE HIGH TEMPERATURES TO BE
SLIGHTLY COOLER THAN THE PREVIOUS DAY...BUT STILL A QUITE
COMFORTABLE MID 70 TO LOW 80 DEGREE RANGE. WINDS WILL THEN TURN TO A
MORE SOUTHERLY DIRECTION ON THE BACKSIDE OF THE SURFACE
HIGH...ALLOWING WARMER WINDS OFF THE LAKE DURING THE FIRST PART OF
THE NIGHT...AND THEN SOUTHERLY WINDS ACROSS THE INTERIOR FOR THE
LAST HALF. THIS SHOULD MODERATE TEMPERATURES TO STAY AT OR ABOVE
NORMAL. UNFORTUNATELY...SURFACE HIGH PRESSURE WILL BE SHORT-LIVED AS
THE FIRST OF SEVERAL SHORTWAVES BEGINS TO TRAVERSE THE AREA BY LATE
WEDNESDAY WITH UPPER LEVEL RIDGING IN PLACE.
MAIN SHORTWAVE AND SURFACE LOW PRESSURE WILL SPREAD ACROSS LAKE
SUPERIOR LATE WEDNESDAY AND THROUGH THE DAY THURSDAY. HOWEVER THERE
IS SOME DISCREPANCY BETWEEN THE MODELS...AS THE NAM IS SLIGHTLY
DELAYED IN THE ARRIVAL OF THE SYSTEM...AND IS MUCH MORE AMPLIFIED
THAN THE OTHER MODELS. REGARDLESS...OVERALL EFFECTS OF THE SYSTEM
WILL BE SIMILAR...STARTING WITH THE INFLUX OF MOIST SOUTHERLY WINDS
/LLVL JET/ AHEAD OF THE SYSTEM AND DECENT WAA. THIS WILL ALLOW HIGH
TEMPERATURES WEDNESDAY TO RISE TO WELL ABOVE NORMAL INLAND /MID TO
UPPER 80S POSSIBLE/. WITH PRESENCE OF AFTERNOON LAKE BREEZES...AND
WARM/MOIST/UNSTABLE AIR IN PLACE...SHOULD SEE SOME AFTERNOON
CONVECTION INLAND AS A RESULT.
AS SYSTEM NEARS...EXPECT A WELL DEFINED AREA OF CONVERGENCE TO SPAWN
PRECIP ACROSS THE ENTIRE CWA WEDNESDAY NIGHT THROUGH
THURSDAY...DESPITE OUR LOCATION IN THE RIGHT EXIT REGION OF A VERY
WEAK JET. MU CAPE VALUES ARE POINTING AT CENTRAL AND WESTERN UPPER
MI GETTING UP TO BETWEEN 1.4-1.8K J/KG IN WEDNESDAY EVENING...AND
THEN MAXING OUT AROUND 2K J/KG OVERNIGHT...THOUGH CAPE WILL BE
FAIRLY SKINNY AND MAINLY CONFINED TO THE MID AND UPPER LEVELS WITH
THE BEST MOISTURE...WHILE THE LOWER LEVELS SHOULD REMAIN FAIRLY DRY.
THAT BEING SAID...MODEL SOUNDINGS SHOW SOME IMPRESSIVE SHEAR
THROUGHOUT THE ENTIRE COLUMN /BOTH DIRECTIONAL AND SPEED/ SO COULD
SEE SOME WIDESPREAD ELEVATED TSRA DEVELOPMENT...BUT WITH LITTLE
MOISTURE IN THE LOW LEVELS...SHOULD/T BE MUCH OF A RAIN SOAKER.
SHORTWAVE AND BEST FORCING SHOULD MOVE OFF TO THE EAST DURING THE
DAY THURSDAY AHEAD OF SURFACE COLD FRONT...BUT THE BREAK IN PRECIP
WILL BE SHORT-LIVED AS LARGER 500MB SHORTWAVE OVER SASKATCHEWAN
FRIDAY AFTERNOON BEGINS TO MOVE ALONG THE SAME TRACK SOUTHEAST
TOWARDS THE UPPER GREAT LAKES. WHILE ALL MODELS ARE IN GOOD
AGREEMENT OF THIS LOW STRENGTHENING AND BECOMING CLOSED OFF AS IT
REACHES THE UPPER GREAT LAKES...THERE IS LITTLE AGREEMENT IN THE
EXACT TIMING AND TRACK...SO WILL GO WITH A GENERAL MODEL CONSENSUS
AT THIS TIME. WITH SOME LOW LEVEL MOISTURE FROM PREVIOUS SYSTEM
ALREADY IN PLACE...COULD SEE SOME SCATTERED SHRA/TSRA DEVELOPMENT AS
EARLY AS FRIDAY MORNING FAR WEST WITH THIS SYSTEM. A STRONG UPPER
LEVEL JET WILL CRUISE OVER UPPER MI BY SATURDAY PUTTING US IN THE
LEFT ENTRANCE REGION...FURTHERING ENHANCING PRECIP CHANCES. PWAT
VALUES WILL QUICKLY RISE TO 160 PERCENT OF NORMAL THROUGH SATURDAY
MORNING AS SURFACE WARM FRONT AND WELL DEFINED AREA OF QVECTOR CONV
TRAVERSES FROM WEST TO EAST. UNLIKE WEDNESDAY NIGHT/THURSDAY...THIS
SYSTEM WILL HAVE ABUNDANT MOISTURE THROUGH ALL LAYERS...SO EXPECT
THIS TO BE A GOOD RAIN EVENT. BY SATURDAY AFTERNOON COLD FRONT WILL
PRESENT IMPRESSIVE FORCING...LATEST GFS HAS 0-3KM COMPUTED CAPE
VALUES MAXING OUT AROUND 1.2K SOUTH CENTRAL...WITH MU CAPE VALUES
2.2-2.6K J/KG OVER MUCH OF THE WESTERN AND CENTRAL CWA. FORECAST
SOUNDINGS SHOW MUCH IMPROVEMENT OVER THE SKINNY ELEVATED CAPE DURING
PREVIOUS EVENT...AND ONCE AGAIN SHEAR LOOKS TO BE VERY IMPRESSIVE
BOTH FOR DIRECTION AND SPEED. DCAPE ON THE OTHER HAND WILL BE ON THE
DIMINISHING TREND DURING THE DAY SATURDAY...SO ONCE STORMS DEVELOP
EXPECT THE MAIN THREAT TO BE HEAVY RAINS...ABUNDANT LIGHTNING...AND
POTENTIAL HAIL.
THE SYSTEM WILL CONTINUE ON ITS TRACK TO THE SOUTHEAST DURING THE
NIGHT SATURDAY...WITH A WELCOME BREAK IN PRECIP BY SUNDAY AFTERNOON
AS HIGH PRESSURE ONCE AGAIN REGAINS CONTROL
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 112 PM EDT MON JUL 30 2012
TOUGH FORECAST FOR THIS AFTERNOON WITH CONFIDENCE LOW IN HOW THE
CONVECTION WILL PLAY OUT THIS AFTERNOON AS A COLD FRONT MOVES
THROUGH. A DISTURBANCE AND ATTENDANT COLD FRONT WITH MOIST UNSTABLE
AIRMASS AT TIME OF PEAK DAYTIME HEATING WILL REDEVELOP SOME SHRA/TS
THIS AFTN AT SAW. SUSPECT THIS ACTIVITY WILL IMPACT MAINLY SAW AS
DRIER AIR WL BE MAKING ITS WAY INTO WRN UPR MI BY THE TIME PEAK
HEATING COMMENCES. SO INCLUDED SPECIFIC MENTION OF TS ONLY AT SAW.
FOLLOWING THE COLD FROPA...FAIRLY HUMID LLVL AIR WL LINGER. SO WITH
UPSLOPE NNW WIND DVLPG BEHIND THE FROPA...EXPECT LO CLDS/FOG/IFR
CONDITIONS AT ALL 3 SITES PER VARIOUS MOS FCST PRODUCTS TONIGHT. THE
LOW CLOUDS AND FOG WILL BURN OFF TUE MORNING AND CONDITIONS WILL
RETURN TO VFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT MON JUL 30 2012
EXPECT SSW WINDS UP TO 20 KTS AND SOME TS IN ADVANCE OF LO PRES TROF
THAT IS FORECAST TO DRIFT ACROSS LAKE SUPERIOR LATE TODAY AND
TONIGHT. BEHIND THE TROF PASSAGE...WINDS WILL SHIFT TO THE NNW AS
HIGH PRESSURE SETS IN...HOWEVER THE W LAKE COULD CONTINUE TO SEE
GUSTS BETWEEN 15 AND 20 KNOTS THROUGH THE MORNING HOURS WITH THIS
WIND DIRECTION. ANOTHER TROF WILL BRING TSRA CHANCES WEDNESDAY
AFTERNOON THROUGH TUESDAY EVENING...AND AGAIN BY FRIDAY. OTHERWISE
EXPECT WINDS TO REMAIN BELOW 15 KNOTS ACROSS THE LAKE FOR THE FCST
PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JMW
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
727 AM EDT MON JUL 30 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 443 AM EDT MON JUL 30 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN GENERAL TROFFING CENTERED NEAR HUDSON BAY AND
PERSISTENT RDG AXIS OVER THE HI PLAINS. WITH LOSS OF DAYTIME
HEATING...SHRA/TS THAT IMPACTED THE CWA LAST EVNG HAVE DIMINISHED.
BUT ANOTHER LINE OF SHRA/TS IS PUSHING SEWD THRU THE MN ARROWHEAD IN
ADVANCE OF POTENT SHRTWV MOVING ESEWD IN MANITOBA TOWARD NW MN AND
LEFT EXIT OF SUPPORTING 75KT H3 JET MAX NOTED IN THE NRN PLAINS.
THIS LINE OF TS PROMPTED THE ISSUANCE OF A WATCH FOR MUCH OF NE
MN...WITH SOME SVR TS GIVEN STEEP MID LVL LAPSE RATES SHOWN ON THE
00Z INL RAOB THAT CONTRIBUTED TO MUCAPE IN EXCESS OF 2000 J/KG AS
WELL AS EFFECTIVE DEEP LYR SHEAR UP TO 40KTS UNDER UNIDIRECTIONAL
WNW FLOW ALF PER SPC ANALYSIS. PRESENCE OF DRIER AIR ALF SHOWN ON
00Z RAOBS HAS CONTRIBUTED TO DCAPE AOA 1000 J/KG IN PORTIONS OF THE
AREA IMPACTED BY THE WATCH. RECENT TRENDS HOWEVER ARE FOR THE STORMS
TO WEAKEN AS THEY MOVE INTO A BIT MORE STABLE AIR IMPACTED BY
NOCTURNAL COOLING AND AXIS OF LOWER H85 DEWPTS OVER CENTRAL MN.
MAIN FCST CONCERNS THIS PACKAGE INCLUDE CONVECTIVE TRENDS INTO TNGT
AND POTENTIAL FOR SVR STORMS.
TODAY...VIGOROUS SHRTWV TO THE NW IS PROGGED TO MOVE TO JUST N OF
INL AT 12Z MON AND THEN INTO FAR NE LK SUP BY 00Z TUE WITH SWATH OF
VIGOROUS DVPA/DEEP LYR QVECTOR CNVGC MOVING W-E ACRS UPR MI.
ALTHOUGH AXIS OF LOWER H85 THETA E CONTRIBUTING TO WEAKENING STORMS
IN MN NOW MAY TEND TO REDUCE COVERAGE/INTENSITY THIS MRNG...ONSET OF
DAYTIME HEATING AND ARRIVAL OF MORE IMPRESSIVE H85 THETA E ADVECTION
BY THIS AFTN IN PRESENCE OF THE HEFTY DYNAMICS SHOULD LEAD TO NMRS
SHRA/TS...ESPECIALLY OVER THE CNTRL AND E WHERE ARRIVAL OF DYNAMICS
APPEAR TO BE MOST IN SYNC WITH DAYTIME HEATING. NAM/GFS FCST SNDGS
INDICATE SBCAPE WL REACH AOA 2000 J/KG AS HI TEMPS RISE WELL INTO
THE 80S AWAY FM LK MODERATION MOST PRONOUNCED OFF LK MI. DRYING ALF
UNDER UNIDIRECTIONAL WNW FLOW ON THE SRN FLANK OF SHRTWV TRACK IS
FCST TO CONTRIBUTE TO SFC-10K FT AGL DELTA THETA E UP TO 25C...VERY
FAVORABLE PER THE MQT SEVERE WX CHECKLIST TO ENHANCE DCAPE. THE
BIGGEST DRAWBACK FOR ORGANIZED SEVERE WX IS FCST RATHER MODEST DEEP
LYR SHEAR ONLY 25-30KTS. THIS WEAKER SHEAR MAY RESULT IN MORE PULSE
SVR EPISODES...WITH THE BETTER CHC FOR ORGANIZED STORMS WHERE LK
BREEZE CNVGC OVER MAINLY THE E HALF MIGHT ENHANCE THE SHEAR AS WELL
AS INCRS LLVL CNVGC AND SHRA/TS COVERAGE. SHRA/TS WL DIMINISH OVER
THE W IN THE AFTN WITH ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/LLVL
DRYING IN THE WAKE OF SHRTWV PASSAGE/ATTENDANT COLD FROPA.
TNGT...DRYING/NEGATIVE H85 THETA E ADVECTION IN THE WAKE OF SHRTWV
MOVING INTO SE ONTARIO AND LOSS OF DAYTIME HEATING WL CAUSE SHRA/TS
TO DIMINISH NW-SE. HOWEVER...MODELS SHOW QUITE A BIT OF LINGERING
LLVL MSTR WITH NNW FLOW IN THE WAKE OF DEPARTING SHRTWV/SFC LO. LO
CLDS MAY BE ESPECIALLY TENACIOUS IN THE UPSLOPE AREAS NEAR LK SUP...
WHERE THERE MAY EVEN BE SOME -DZ/SPRINKLES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 443 AM EDT MON JUL 30 2012
VERY ACTIVE FORECAST PERIOD...AS UPPER MI SITS IN AN UPPER LEVEL
TROUGHING PATTERN THROUGH TUESDAY...BEFORE STRONG RIDGING PATTERN
OVER MUCH OF THE CONUS BEGINS TO MOVE EASTWARD INTO THE REGION.
ALONG THIS RIDGE...SEVERAL SHORTWAVES WILL PASS OVER UPPER MI
BRINGING CHANCES FOR TSRA WED AND THUR AND THEN AGAIN DURING THE
WEEKEND.
AFTER EXITING 500MB SHORTWAVE DURING THE DAY TUESDAY...STRONG
RIDGING WILL BEGIN TO PUSH IN FROM WEST TO EAST...WHICH WILL ALSO
TRANSLATE TO SURFACE HIGH PRESSURE. AS WINDS TURN TO A NORTHERLY
DIRECTION...EXPECT AN INFLUX OF DRY AIR AND CLEARING SKIES ACROSS
THE REGION. SUCH A WIND DIRECTION WILL CAUSE HIGH TEMPERATURES TO BE
SLIGHTLY COOLER THAN THE PREVIOUS DAY...BUT STILL A QUITE
COMFORTABLE MID 70 TO LOW 80 DEGREE RANGE. WINDS WILL THEN TURN TO A
MORE SOUTHERLY DIRECTION ON THE BACKSIDE OF THE SURFACE
HIGH...ALLOWING WARMER WINDS OFF THE LAKE DURING THE FIRST PART OF
THE NIGHT...AND THEN SOUTHERLY WINDS ACROSS THE INTERIOR FOR THE
LAST HALF. THIS SHOULD MODERATE TEMPERATURES TO STAY AT OR ABOVE
NORMAL. UNFORTUNATELY...SURFACE HIGH PRESSURE WILL BE SHORT-LIVED AS
THE FIRST OF SEVERAL SHORTWAVES BEGINS TO TRAVERSE THE AREA BY LATE
WEDNESDAY WITH UPPER LEVEL RIDGING IN PLACE.
MAIN SHORTWAVE AND SURFACE LOW PRESSURE WILL SPREAD ACROSS LAKE
SUPERIOR LATE WEDNESDAY AND THROUGH THE DAY THURSDAY. HOWEVER THERE
IS SOME DISCREPANCY BETWEEN THE MODELS...AS THE NAM IS SLIGHTLY
DELAYED IN THE ARRIVAL OF THE SYSTEM...AND IS MUCH MORE AMPLIFIED
THAN THE OTHER MODELS. REGARDLESS...OVERALL EFFECTS OF THE SYSTEM
WILL BE SIMILAR...STARTING WITH THE INFLUX OF MOIST SOUTHERLY WINDS
/LLVL JET/ AHEAD OF THE SYSTEM AND DECENT WAA. THIS WILL ALLOW HIGH
TEMPERATURES WEDNESDAY TO RISE TO WELL ABOVE NORMAL INLAND /MID TO
UPPER 80S POSSIBLE/. WITH PRESENCE OF AFTERNOON LAKE BREEZES...AND
WARM/MOIST/UNSTABLE AIR IN PLACE...SHOULD SEE SOME AFTERNOON
CONVECTION INLAND AS A RESULT.
AS SYSTEM NEARS...EXPECT A WELL DEFINED AREA OF CONVERGENCE TO SPAWN
PRECIP ACROSS THE ENTIRE CWA WEDNESDAY NIGHT THROUGH
THURSDAY...DESPITE OUR LOCATION IN THE RIGHT EXIT REGION OF A VERY
WEAK JET. MU CAPE VALUES ARE POINTING AT CENTRAL AND WESTERN UPPER
MI GETTING UP TO BETWEEN 1.4-1.8K J/KG IN WEDNESDAY EVENING...AND
THEN MAXING OUT AROUND 2K J/KG OVERNIGHT...THOUGH CAPE WILL BE
FAIRLY SKINNY AND MAINLY CONFINED TO THE MID AND UPPER LEVELS WITH
THE BEST MOISTURE...WHILE THE LOWER LEVELS SHOULD REMAIN FAIRLY DRY.
THAT BEING SAID...MODEL SOUNDINGS SHOW SOME IMPRESSIVE SHEAR
THROUGHOUT THE ENTIRE COLUMN /BOTH DIRECTIONAL AND SPEED/ SO COULD
SEE SOME WIDESPREAD ELEVATED TSRA DEVELOPMENT...BUT WITH LITTLE
MOISTURE IN THE LOW LEVELS...SHOULD/T BE MUCH OF A RAIN SOAKER.
SHORTWAVE AND BEST FORCING SHOULD MOVE OFF TO THE EAST DURING THE
DAY THURSDAY AHEAD OF SURFACE COLD FRONT...BUT THE BREAK IN PRECIP
WILL BE SHORT-LIVED AS LARGER 500MB SHORTWAVE OVER SASKATCHEWAN
FRIDAY AFTERNOON BEGINS TO MOVE ALONG THE SAME TRACK SOUTHEAST
TOWARDS THE UPPER GREAT LAKES. WHILE ALL MODELS ARE IN GOOD
AGREEMENT OF THIS LOW STRENGTHENING AND BECOMING CLOSED OFF AS IT
REACHES THE UPPER GREAT LAKES...THERE IS LITTLE AGREEMENT IN THE
EXACT TIMING AND TRACK...SO WILL GO WITH A GENERAL MODEL CONSENSUS
AT THIS TIME. WITH SOME LOW LEVEL MOISTURE FROM PREVIOUS SYSTEM
ALREADY IN PLACE...COULD SEE SOME SCATTERED SHRA/TSRA DEVELOPMENT AS
EARLY AS FRIDAY MORNING FAR WEST WITH THIS SYSTEM. A STRONG UPPER
LEVEL JET WILL CRUISE OVER UPPER MI BY SATURDAY PUTTING US IN THE
LEFT ENTRANCE REGION...FURTHERING ENHANCING PRECIP CHANCES. PWAT
VALUES WILL QUICKLY RISE TO 160 PERCENT OF NORMAL THROUGH SATURDAY
MORNING AS SURFACE WARM FRONT AND WELL DEFINED AREA OF QVECTOR CONV
TRAVERSES FROM WEST TO EAST. UNLIKE WEDNESDAY NIGHT/THURSDAY...THIS
SYSTEM WILL HAVE ABUNDANT MOISTURE THROUGH ALL LAYERS...SO EXPECT
THIS TO BE A GOOD RAIN EVENT. BY SATURDAY AFTERNOON COLD FRONT WILL
PRESENT IMPRESSIVE FORCING...LATEST GFS HAS 0-3KM COMPUTED CAPE
VALUES MAXING OUT AROUND 1.2K SOUTH CENTRAL...WITH MU CAPE VALUES
2.2-2.6K J/KG OVER MUCH OF THE WESTERN AND CENTRAL CWA. FORECAST
SOUNDINGS SHOW MUCH IMPROVEMENT OVER THE SKINNY ELEVATED CAPE DURING
PREVIOUS EVENT...AND ONCE AGAIN SHEAR LOOKS TO BE VERY IMPRESSIVE
BOTH FOR DIRECTION AND SPEED. DCAPE ON THE OTHER HAND WILL BE ON THE
DIMINISHING TREND DURING THE DAY SATURDAY...SO ONCE STORMS DEVELOP
EXPECT THE MAIN THREAT TO BE HEAVY RAINS...ABUNDANT LIGHTNING...AND
POTENTIAL HAIL.
THE SYSTEM WILL CONTINUE ON ITS TRACK TO THE SOUTHEAST DURING THE
NIGHT SATURDAY...WITH A WELCOME BREAK IN PRECIP BY SUNDAY AFTERNOON
AS HIGH PRESSURE ONCE AGAIN REGAINS CONTROL
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 726 AM EDT MON JUL 30 2012
CLUSTER OF SHRA/TS IN ADVANCE OF STRONG DISTURBANCE MOVING ESEWD
THRU ONTARIO JUST N OF THE BORDER IS IN THE PROCESS OF DIMINISHING.
SOME SHRA MAY REACH SAW...BUT SUSPECT THESE WILL WEAKEN...SO
INCLUDED ONLY MENTION OF VCSH. ALTHOUGH THERE MAY BE SOME MVFR CIGS
AT CMX FOR A FEW HRS THIS MRNG AFT THE HEAVIER SHRA THERE...EXPECT
MAINLY VFR CONDITIONS THIS MRNG. CLOSER APRCH OF THIS DISTURBANCE
AND ATTENDANT COLD FNT WITH MOIST UNSTABLE AIRMASS AT TIME OF PEAK
DAYTIME HEATING WL TRIGGER MORE SHRA/TS THIS AFTN. SUSPECT THIS
ACTIVITY WILL IMPACT MAINLY SAW AS DRIER AIR WL BE MAKING ITS WAY
INTO WRN UPR MI BY THE TIME PEAK HEATING COMMENCES. SO INCLUDED
SPECIFIC MENTION OF TS ONLY AT SAW. FOLLOWING THE COLD FROPA...
FAIRLY HUMID LLVL AIR WL LINGER. SO WITH UPSLOPE NNW WIND DVLPG
BEHIND THE FROPA...EXPECT LO CLDS/FOG/IFR CONDITIONS AT ALL 3 SITES
PER VARIOUS MOS FCST PRODUCTS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT MON JUL 30 2012
EXPECT SSW WINDS UP TO 20 KTS AND SOME TS IN ADVANCE OF LO PRES TROF
THAT IS FORECAST TO DRIFT ACROSS LAKE SUPERIOR LATE TODAY AND
TONIGHT. BEHIND THE TROF PASSAGE...WINDS WILL SHIFT TO THE NNW AS
HIGH PRESSURE SETS IN...HOWEVER THE W LAKE COULD CONTINUE TO SEE
GUSTS BETWEEN 15 AND 20 KNOTS THROUGH THE MORNING HOURS WITH THIS
WIND DIRECTION. ANOTHER TROF WILL BRING TSRA CHANCES WEDNESDAY
AFTERNOON THROUGH TUESDAY EVENING...AND AGAIN BY FRIDAY. OTHERWISE
EXPECT WINDS TO REMAIN BELOW 15 KNOTS ACROSS THE LAKE FOR THE FCST
PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JMW
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
444 AM EDT MON JUL 30 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 443 AM EDT MON JUL 30 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN GENERAL TROFFING CENTERED NEAR HUDSON BAY AND
PERSISTENT RDG AXIS OVER THE HI PLAINS. WITH LOSS OF DAYTIME
HEATING...SHRA/TS THAT IMPACTED THE CWA LAST EVNG HAVE DIMINISHED.
BUT ANOTHER LINE OF SHRA/TS IS PUSHING SEWD THRU THE MN ARROWHEAD IN
ADVANCE OF POTENT SHRTWV MOVING ESEWD IN MANITOBA TOWARD NW MN AND
LEFT EXIT OF SUPPORTING 75KT H3 JET MAX NOTED IN THE NRN PLAINS.
THIS LINE OF TS PROMPTED THE ISSUANCE OF A WATCH FOR MUCH OF NE
MN...WITH SOME SVR TS GIVEN STEEP MID LVL LAPSE RATES SHOWN ON THE
00Z INL RAOB THAT CONTRIBUTED TO MUCAPE IN EXCESS OF 2000 J/KG AS
WELL AS EFFECTIVE DEEP LYR SHEAR UP TO 40KTS UNDER UNIDIRECTIONAL
WNW FLOW ALF PER SPC ANALYSIS. PRESENCE OF DRIER AIR ALF SHOWN ON
00Z RAOBS HAS CONTRIBUTED TO DCAPE AOA 1000 J/KG IN PORTIONS OF THE
AREA IMPACTED BY THE WATCH. RECENT TRENDS HOWEVER ARE FOR THE STORMS
TO WEAKEN AS THEY MOVE INTO A BIT MORE STABLE AIR IMPACTED BY
NOCTURNAL COOLING AND AXIS OF LOWER H85 DEWPTS OVER CENTRAL MN.
MAIN FCST CONCERNS THIS PACKAGE INCLUDE CONVECTIVE TRENDS INTO TNGT
AND POTENTIAL FOR SVR STORMS.
TODAY...VIGOROUS SHRTWV TO THE NW IS PROGGED TO MOVE TO JUST N OF
INL AT 12Z MON AND THEN INTO FAR NE LK SUP BY 00Z TUE WITH SWATH OF
VIGOROUS DVPA/DEEP LYR QVECTOR CNVGC MOVING W-E ACRS UPR MI.
ALTHOUGH AXIS OF LOWER H85 THETA E CONTRIBUTING TO WEAKENING STORMS
IN MN NOW MAY TEND TO REDUCE COVERAGE/INTENSITY THIS MRNG...ONSET OF
DAYTIME HEATING AND ARRIVAL OF MORE IMPRESSIVE H85 THETA E ADVECTION
BY THIS AFTN IN PRESENCE OF THE HEFTY DYNAMICS SHOULD LEAD TO NMRS
SHRA/TS...ESPECIALLY OVER THE CNTRL AND E WHERE ARRIVAL OF DYNAMICS
APPEAR TO BE MOST IN SYNC WITH DAYTIME HEATING. NAM/GFS FCST SNDGS
INDICATE SBCAPE WL REACH AOA 2000 J/KG AS HI TEMPS RISE WELL INTO
THE 80S AWAY FM LK MODERATION MOST PRONOUNCED OFF LK MI. DRYING ALF
UNDER UNIDIRECTIONAL WNW FLOW ON THE SRN FLANK OF SHRTWV TRACK IS
FCST TO CONTRIBUTE TO SFC-10K FT AGL DELTA THETA E UP TO 25C...VERY
FAVORABLE PER THE MQT SEVERE WX CHECKLIST TO ENHANCE DCAPE. THE
BIGGEST DRAWBACK FOR ORGANIZED SEVERE WX IS FCST RATHER MODEST DEEP
LYR SHEAR ONLY 25-30KTS. THIS WEAKER SHEAR MAY RESULT IN MORE PULSE
SVR EPISODES...WITH THE BETTER CHC FOR ORGANIZED STORMS WHERE LK
BREEZE CNVGC OVER MAINLY THE E HALF MIGHT ENHANCE THE SHEAR AS WELL
AS INCRS LLVL CNVGC AND SHRA/TS COVERAGE. SHRA/TS WL DIMINISH OVER
THE W IN THE AFTN WITH ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/LLVL
DRYING IN THE WAKE OF SHRTWV PASSAGE/ATTENDANT COLD FROPA.
TNGT...DRYING/NEGATIVE H85 THETA E ADVECTION IN THE WAKE OF SHRTWV
MOVING INTO SE ONTARIO AND LOSS OF DAYTIME HEATING WL CAUSE SHRA/TS
TO DIMINISH NW-SE. HOWEVER...MODELS SHOW QUITE A BIT OF LINGERING
LLVL MSTR WITH NNW FLOW IN THE WAKE OF DEPARTING SHRTWV/SFC LO. LO
CLDS MAY BE ESPECIALLY TENACIOUS IN THE UPSLOPE AREAS NEAR LK SUP...
WHERE THERE MAY EVEN BE SOME -DZ/SPRINKLES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 443 AM EDT MON JUL 30 2012
VERY ACTIVE FORECAST PERIOD...AS UPPER MI SITS IN AN UPPER LEVEL
TROUGHING PATTERN THROUGH TUESDAY...BEFORE STRONG RIDGING PATTERN
OVER MUCH OF THE CONUS BEGINS TO MOVE EASTWARD INTO THE REGION.
ALONG THIS RIDGE...SEVERAL SHORTWAVES WILL PASS OVER UPPER MI
BRINGING CHANCES FOR TSRA WED AND THUR AND THEN AGAIN DURING THE
WEEKEND.
AFTER EXITING 500MB SHORTWAVE DURING THE DAY TUESDAY...STRONG
RIDGING WILL BEGIN TO PUSH IN FROM WEST TO EAST...WHICH WILL ALSO
TRANSLATE TO SURFACE HIGH PRESSURE. AS WINDS TURN TO A NORTHERLY
DIRECTION...EXPECT AN INFLUX OF DRY AIR AND CLEARING SKIES ACROSS
THE REGION. SUCH A WIND DIRECTION WILL CAUSE HIGH TEMPERATURES TO BE
SLIGHTLY COOLER THAN THE PREVIOUS DAY...BUT STILL A QUITE
COMFORTABLE MID 70 TO LOW 80 DEGREE RANGE. WINDS WILL THEN TURN TO A
MORE SOUTHERLY DIRECTION ON THE BACKSIDE OF THE SURFACE
HIGH...ALLOWING WARMER WINDS OFF THE LAKE DURING THE FIRST PART OF
THE NIGHT...AND THEN SOUTHERLY WINDS ACROSS THE INTERIOR FOR THE
LAST HALF. THIS SHOULD MODERATE TEMPERATURES TO STAY AT OR ABOVE
NORMAL. UNFORTUNATELY...SURFACE HIGH PRESSURE WILL BE SHORT-LIVED AS
THE FIRST OF SEVERAL SHORTWAVES BEGINS TO TRAVERSE THE AREA BY LATE
WEDNESDAY WITH UPPER LEVEL RIDGING IN PLACE.
MAIN SHORTWAVE AND SURFACE LOW PRESSURE WILL SPREAD ACROSS LAKE
SUPERIOR LATE WEDNESDAY AND THROUGH THE DAY THURSDAY. HOWEVER THERE
IS SOME DISCREPANCY BETWEEN THE MODELS...AS THE NAM IS SLIGHTLY
DELAYED IN THE ARRIVAL OF THE SYSTEM...AND IS MUCH MORE AMPLIFIED
THAN THE OTHER MODELS. REGARDLESS...OVERALL EFFECTS OF THE SYSTEM
WILL BE SIMILAR...STARTING WITH THE INFLUX OF MOIST SOUTHERLY WINDS
/LLVL JET/ AHEAD OF THE SYSTEM AND DECENT WAA. THIS WILL ALLOW HIGH
TEMPERATURES WEDNESDAY TO RISE TO WELL ABOVE NORMAL INLAND /MID TO
UPPER 80S POSSIBLE/. WITH PRESENCE OF AFTERNOON LAKE BREEZES...AND
WARM/MOIST/UNSTABLE AIR IN PLACE...SHOULD SEE SOME AFTERNOON
CONVECTION INLAND AS A RESULT.
AS SYSTEM NEARS...EXPECT A WELL DEFINED AREA OF CONVERGENCE TO SPAWN
PRECIP ACROSS THE ENTIRE CWA WEDNESDAY NIGHT THROUGH
THURSDAY...DESPITE OUR LOCATION IN THE RIGHT EXIT REGION OF A VERY
WEAK JET. MU CAPE VALUES ARE POINTING AT CENTRAL AND WESTERN UPPER
MI GETTING UP TO BETWEEN 1.4-1.8K J/KG IN WEDNESDAY EVENING...AND
THEN MAXING OUT AROUND 2K J/KG OVERNIGHT...THOUGH CAPE WILL BE
FAIRLY SKINNY AND MAINLY CONFINED TO THE MID AND UPPER LEVELS WITH
THE BEST MOISTURE...WHILE THE LOWER LEVELS SHOULD REMAIN FAIRLY DRY.
THAT BEING SAID...MODEL SOUNDINGS SHOW SOME IMPRESSIVE SHEAR
THROUGHOUT THE ENTIRE COLUMN /BOTH DIRECTIONAL AND SPEED/ SO COULD
SEE SOME WIDESPREAD ELEVATED TSRA DEVELOPMENT...BUT WITH LITTLE
MOISTURE IN THE LOW LEVELS...SHOULD/T BE MUCH OF A RAIN SOAKER.
SHORTWAVE AND BEST FORCING SHOULD MOVE OFF TO THE EAST DURING THE
DAY THURSDAY AHEAD OF SURFACE COLD FRONT...BUT THE BREAK IN PRECIP
WILL BE SHORT-LIVED AS LARGER 500MB SHORTWAVE OVER SASKATCHEWAN
FRIDAY AFTERNOON BEGINS TO MOVE ALONG THE SAME TRACK SOUTHEAST
TOWARDS THE UPPER GREAT LAKES. WHILE ALL MODELS ARE IN GOOD
AGREEMENT OF THIS LOW STRENGTHENING AND BECOMING CLOSED OFF AS IT
REACHES THE UPPER GREAT LAKES...THERE IS LITTLE AGREEMENT IN THE
EXACT TIMING AND TRACK...SO WILL GO WITH A GENERAL MODEL CONSENSUS
AT THIS TIME. WITH SOME LOW LEVEL MOISTURE FROM PREVIOUS SYSTEM
ALREADY IN PLACE...COULD SEE SOME SCATTERED SHRA/TSRA DEVELOPMENT AS
EARLY AS FRIDAY MORNING FAR WEST WITH THIS SYSTEM. A STRONG UPPER
LEVEL JET WILL CRUISE OVER UPPER MI BY SATURDAY PUTTING US IN THE
LEFT ENTRANCE REGION...FURTHERING ENHANCING PRECIP CHANCES. PWAT
VALUES WILL QUICKLY RISE TO 160 PERCENT OF NORMAL THROUGH SATURDAY
MORNING AS SURFACE WARM FRONT AND WELL DEFINED AREA OF QVECTOR CONV
TRAVERSES FROM WEST TO EAST. UNLIKE WEDNESDAY NIGHT/THURSDAY...THIS
SYSTEM WILL HAVE ABUNDANT MOISTURE THROUGH ALL LAYERS...SO EXPECT
THIS TO BE A GOOD RAIN EVENT. BY SATURDAY AFTERNOON COLD FRONT WILL
PRESENT IMPRESSIVE FORCING...LATEST GFS HAS 0-3KM COMPUTED CAPE
VALUES MAXING OUT AROUND 1.2K SOUTH CENTRAL...WITH MU CAPE VALUES
2.2-2.6K J/KG OVER MUCH OF THE WESTERN AND CENTRAL CWA. FORECAST
SOUNDINGS SHOW MUCH IMPROVEMENT OVER THE SKINNY ELEVATED CAPE DURING
PREVIOUS EVENT...AND ONCE AGAIN SHEAR LOOKS TO BE VERY IMPRESSIVE
BOTH FOR DIRECTION AND SPEED. DCAPE ON THE OTHER HAND WILL BE ON THE
DIMINISHING TREND DURING THE DAY SATURDAY...SO ONCE STORMS DEVELOP
EXPECT THE MAIN THREAT TO BE HEAVY RAINS...ABUNDANT LIGHTNING...AND
POTENTIAL HAIL.
THE SYSTEM WILL CONTINUE ON ITS TRACK TO THE SOUTHEAST DURING THE
NIGHT SATURDAY...WITH A WELCOME BREAK IN PRECIP BY SUNDAY AFTERNOON
AS HIGH PRESSURE ONCE AGAIN REGAINS CONTROL
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 131 AM EDT MON JUL 30 2012
STRONG UPPER DISTURBANCE MOVING THROUGH SOUTH CENTRAL CANADA HAS
PRODUCED CLUSTER OF TSRA OVER WRN ONTARIO AND NRN MN EARLY THIS
MORNING. THIS DISTURBANCE WILL MOVE ACROSS THE UPPER GREAT LAKES ON
MONDAY BRINGING A CHANCE OF SHRA AND POSSIBLY THUNDERSTORMS TO THE
TAF SITES. THE BEST CHANCE OF THUNDERSTORMS WILL BE OVER KSAW WHERE
DAYTIME HEATING/INSTABILITY WILL BE ABLE TO BUILD BEFORE THE ARRIVAL
OF THE DISTURBANCE AND ASSOC SFC TROUGH. DEVELOPING LAKE BREEZE
BOUNDARIES MAY ALSO HELP AFTERNOON CONVECTION ALONG AT KSAW. EXPECT
ANY LINGERING SHRA TO END AT KIWD AND KCMX BY EARLY AFTERNOON AND AT
KSAW BY EARLY EVENING IN WAKE OF THE SFC TROUGH. GIVEN UNCERTAINTY
WITH THE EXTENT AND TRACK OF PCPN OVER LAKE SUPERIOR ELECTED NOT TO
INCLUDE ANY MVFR LAKE STRATUS OR FOG MENTION IN THE TAFS MON EVENING
ALTHOUGH THIS POSSIBILITY MAY NEED TO BE CONSIDERED...ESPECIALLY
ONCE WINDS SHIFT NW BEHIND THE TROUGH LATE MONDAY INTO MONDAY
EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT MON JUL 30 2012
EXPECT SSW WINDS UP TO 20 KTS AND SOME TS IN ADVANCE OF LO PRES TROF
THAT IS FORECAST TO DRIFT ACROSS LAKE SUPERIOR LATE TODAY AND
TONIGHT. BEHIND THE TROF PASSAGE...WINDS WILL SHIFT TO THE NNW AS
HIGH PRESSURE SETS IN...HOWEVER THE W LAKE COULD CONTINUE TO SEE
GUSTS BETWEEN 15 AND 20 KNOTS THROUGH THE MORNING HOURS WITH THIS
WIND DIRECTION. ANOTHER TROF WILL BRING TSRA CHANCES WEDNESDAY
AFTERNOON THROUGH TUESDAY EVENING...AND AGAIN BY FRIDAY. OTHERWISE
EXPECT WINDS TO REMAIN BELOW 15 KNOTS ACROSS THE LAKE FOR THE FCST
PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JMW
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
605 AM CDT MON JUL 30 2012
.UPDATED FOR 12Z AVIATION DISCUSSION BELOW...
.DISCUSSION...
OVERVIEW...NEAR TO ABOVE NORMAL TEMPS EXPECTED TO CONTINUE WITH
NOTABLE COOLING IN THE EXTENDED DUE TO ARRIVAL OF ANOTHER UPPER
LOW. STILL SOME TIMING ISSUES TO WORK OUT YET...BUT DECENT CHANCES
FOR RAIN ON WEDNESDAY AND SATURDAY. SEVERAL SUBTLE SHORTWAVES COME
RIPPLING THROUGH THE AREA OVER THE NEXT FEW DAYS...BUT MOST OF
THESE FEATURES WILL MOVE HARMLESSLY THROUGH THE FORECAST AREA WITH
LITTLE CHANGE TO OUR SENSIBLE WEATHER.
TWO AREAS OF PRECIPITATION THIS MORNING...ONE IN THE NORTHERN
PLAINS AND THE OTHER IN NORTHERN MN BOTH BEING ASSISTED BY STRONG
250MB JET STRETCHED OUT ACROSS SD...MN...IA/WI AND IL. THE
FORECAST AREA IS ACTUALLY IN AN ZONE WHERE THE QG VERTICAL VELOCITY
SUGGESTS SINKING AIR. THERE ARE ALSO A COUPLE COMPACT SHORTWAVES
HELPING TO DRIVE THE CONVECTION. THE AREA OF THUNDERSTORMS TO OUR
SOUTH IS EMBEDDED IN THAT MOIST TONGUE OF MONSOONAL AIR STREAMING
OUT OF THE FOUR CORNERS. MEANWHILE...THE NORTHERN SHORT WAVE IS
EMBEDDED IN CYCLONIC CURVATURE. WHILE IT HAS LOST SOME OF ITS
DEFINITION...THIS FEATURE WILL STILL PLAY A ROLE IN KEEPING THE
THREAT FOR RAIN ACROSS WESTERN WI THIS MORNING. BY THIS
AFTERNOON...THE NORTHERN STREAM SFC TROUGH AND CORRESPONDING COLD
FRONT WILL THROUGH THE AREA. WHILE CONVERGENCE FROM THE SURFACE TO
OVERLY STRONG...THERE WILL DEFINITELY BE SOME WEAK FGEN AND QG
VERTICALLY VELOCITY THIS AFTERNOON IN WESTERN WI. MUCAPE HAS
FALLEN OFF THIS MORNING...BUT SHOULD BE ENOUGH TIME OUT AHEAD OF
THE SURFACE WAVE TO BUILD SOME INSTABILITY. INCLUDED SMALL POPS IN
WEST CENTRAL WI...BUT ACTIVITY MAY IN FACT BE EVEN FURTHER EAST
GIVEN THE CURRENT SPEED OF THINGS. THIS THINKING FALLS IN LINE
WITH THE SPC DAY ONE SLIGHT RISK AREA.
EXPECT IT TO BE A BIT COOLER AND DRIER IN THE WAKE OF THE SURFACE
TROUGH WHEN THE HIGH BUILDS IN ON TUESDAY. POPS/WEATHER GET A BIT
MORE COMPLICATED WEDNESDAY INTO FRIDAY WITH MUCH LESS
AMPLIFICATION TO THE LONG WAVE PATTERN AND A SLOWLY EVOLVING
SURFACE TROUGH JUST WEST OF THE FORECAST AREA. THERE WILL
CERTAINLY BE THUNDERSTORMS AROUND...LIKELY AIDED BY THE NOCTURNAL
LOW LEVEL JET AND IN THE DAKOTAS AND WESTERN MN.
IN THE EXTENDED...THE EC HAS BEEN TRENDING WARMER EARLY/MIDDLE OF
NEXT WEEK OVER THE LAST COUPLE AND THE GFS HAS BEEN TRENDING
COOLER. THE 500MB HEIGHTS AND 850MB TEMPS OFF THE EC SUGGEST ONCE
A AGAIN TEMPS WELL INTO THE 90S. THE RECENT GFS SOLUTIONS HAVE
BEEN MUCH FLATTER WITH THE HEIGHTS AND COOLER AT 850 MB. THE
ENSEMBLE MEANS OF THE EC/GFS SUGGEST THE OPERATIONAL RUNS ARE NOT
COMPLETELY OFF BASE. JUST HAVE TO WAIT AND SEE IF THE SOLUTIONS
BEGIN TO CONVERGE OVER THE NEXT COUPLE DAYS.
&&
.AVIATION.../12Z TAF ISSUANCE/
SOME FOG ISSUES AROUND SOUTHERN AREAS AHEAD OF INCOMING FRONT. MAY
HAVE TO INCLUDE SOME AT KEAU/KRNH EARLY. RARITY OF LATE WITH FRONT
MOVING THROUGH THE CWA ON THE DRY SIDE THROUGH THE MORNING. WILL
MOVE THROUGH THE KEAU AREA AROUND 19Z. THIS WOULD BE THE ONLY AREA
THAT WOULD HAVE A SMALL CHANCE OF SEEING AND CONVECTION AS WELL.
WILL LEAVE IT OUT FOR NOW. WINDS BECOMING NORTHWEST BEHIND FRONT AND
COULD MIX OUT A 20 KNOT GUST OR SO. THE RAP HAS BEEN STRONGER WITH
THE WIND LAST SEVERAL RUNS. SOME CUMULUS EXPECTED AS WELL...WITH
SOME SMALL NEGATIVE CU RULES OVER THE EASTERN AREAS. SHOULD LIFT
AND DISSIPATE BY EVENING. SKC OVERNIGHT EXPECTED WITH WINDS BECOMING
MORE NORTH/NORTHEAST AND LIGHT AS RIDGE BUILDS IN. LEFT OUT FOG
MENTION FOR NOW DUE TO DRIER DEWPOINTS EXPECTED.
KMSP...DRY FRONT MOVING THROUGH AROUND 18Z WITH WINDS TURNING MORE
NORTHWEST WITH SOME GUSTS TO 20 KNOTS POSSIBLE IN THE AFTERNOON.
FEW CUMULUS ALONG WITH SOME HIGH OR MID LEVEL CLOUDS AS FRONT EXITS
TO THE SOUTHEAST THIS AFTERNOON. WINDS DIMINISHING THIS EVENING
BECOMING LIGHT EAST TUESDAY MORNING. SKC EXPECTED OVERNIGHT INTO
TUESDAY.
//OUTLOOK
TUESDAY THROUGH TUESDAY NIGHT...VFR.
WEDNESDAY...MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/DE
AREA FORECAST DISCUSSION
NWS DULUTH MN
326 AM CDT MON JUL 30 2012
.SHORT TERM...THIS MORNING THROUGH TUESDAY...
LOW PRESSURE NORTH OF LAKE SUPERIOR WILL DRAG AN INSIGNIFICANT
COLD FRONT THROUG DULUTH LATE THIS MORNING AND SEND IT BEYOND OUR
AREA BY THIS EVENING. TROUGHINESS ALOFT WILL STIMULATE SCATTERED
SHOWERS OR THUNDERSTORMS. WITH OUR POSITION IN THE LEFT-ENTRANCE
REGION OF A JET AND DRY AIR AT MID LEVELS...CONVECTIVE DEVELOPMENT
WILL BE UNREMARKABLE. SURFACE HIGH PRESSURE WILL BUILD TOWARD OUR
AREA TONIGHT AND LINGER OVER LAKE SUPERIOR TUESDAY. HEIGHTS ALOFT
WILL QUICKLY BECOME ANTICYCLONIC THIS EVENING WITH ANOTHER UPPER
RIDGE BUILDING TOWARD OUR AREA TUESDAY. EVEN WITH RESIDUAL
MOISTURE ALLOWING CLOUDS...ESPECIALLY NORTH OF DULUTH TUESDAY...
AFTERNOON TEMPERATURES WILL REMAIN WARMER THAN NORMAL AND THE HIGH
HUMIDITY WILL CONTINUE BOTH DAYS.
.LONG TERM...TUESDAY NIGHT THROUGH THE COMING WEEKEND...
THE NORTHLAND WILL BEGIN THE PERIOD IN NORTHWEST FLOW ALOFT DUE TO A
A MID/UPPER LEVEL RIDGE OF HIGH PRESSURE OVER THE SOUTHERN AND
WESTERN PLAINS. THIS WILL BRING A SHORTWAVE TROUGH PASSAGE THAT
COULD BRING SHOWERS AND THUNDERSTORMS TO THE NORTHLAND LATE TUESDAY
NIGHT THROUGH THURSDAY. THE RIDGE WILL BEGIN TO GET FLATTENED AFTER
THE MIDDLE OF THE WEEK AS A MORE POTENT SHORTWAVE TROUGH IN SOUTH
CENTRAL CANADA APPROACHES THE REGION. THAT SHORTWAVE TROUGH COULD
BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE NORTHLAND
FRIDAY THROUGH SATURDAY NIGHT. THE END OF THE FORECAST PERIOD MIGHT
SEE HIGH PRESSURE RETURN TO THE FA. TEMPERATURES THROUGH THE PERIOD
WILL BEGIN ABOVE NORMAL...THEN TRANSITION TO CLOSE TO NORMAL FOR
LATE THIS WEEK AND INTO EARLY NEXT WEEK.
&&
.AVIATION...07/30/06Z ISSUANCE...
LINE OF STORMS WILL MOVE FROM NW TO SE OVER THE NORTHERN HALF OF THE
FA AND AFFECT INL/HIB/DLH. IN THE VCNTY OF THE STORMS...MVFR
CIGS...GUSTY WINDS TO 35 KTS...HEAVY RAIN AND SMALL HAIL IS
POSSIBLE. LATEST HRRR HAS THE STORMS DEPARTING THE INL TERMINAL BY
09Z...HIB BY 11Z AND DLH BY 13Z. THE COLD FRONT WILL FOLLOW QUICKLY
BEHIND THE STORMS AND TURN THE SFC WIND TO THE NW AND BECOME GUSTY
WITH A CLEARING SKY. GUSTY WINDS WILL SUBSIDE NEAR SUNSET. CIGS WILL
BE IN THE VFR RANGE AHEAD OF STORMS AND AFTER FROPA.
&&
.POINT TEMPS/POPS...
DLH 84 61 81 63 / 40 10 10 0
INL 82 57 85 63 / 40 10 10 30
BRD 85 62 85 66 / 20 10 0 10
HYR 86 60 85 61 / 40 10 0 0
ASX 84 63 83 62 / 50 10 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...EOM
LONG TERM....GROCHOCINSKI
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS DULUTH MN
1207 AM CDT MON JUL 30 2012
.AVIATION...06Z TAFS.
LINE OF STORMS WILL MOVE FROM NW TO SE OVER THE NORTHERN HALF OF THE
FA AND AFFECT INL/HIB/DLH. IN THE VCNTY OF THE STORMS...MVFR
CIGS...GUSTY WINDS TO 35 KTS...HEAVY RAIN AND SMALL HAIL IS
POSSIBLE. LATEST HRRR HAS THE STORMS DEPARTING THE INL TERMINAL BY
09Z...HIB BY 11Z AND DLH BY 13Z. THE COLD FRONT WILL FOLLOW QUICKLY
BEHIND THE STORMS AND TURN THE SFC WIND TO THE NW AND BECOME GUSTY
WITH A CLEARING SKY. GUSTY WINDS WILL SUBSIDE NEAR SUNSET. CIGS WILL
BE IN THE VFR RANGE AHEAD OF STORMS AND AFTER FROPA.
&&
.PREV DISCUSSION... /ISSUED 916 PM CDT SUN JUL 29 2012/
UPDATE...BRIEF BREAK IN THE ACTION ATTM. HOWEVER...THUNDERSTORMS
COMPLEX JUST N OF THE CANADIAN BORDER WILL MOVE INTO NORTHERN MN.
MADE SOME MINOR ADJUSTMENTS AS STORMS SHOULD STAY N OF THE
SOUTHERN TIER OF THE FA UNTIL AFTER MIDNIGHT.
PREV DISCUSSION... /ISSUED 617 PM CDT SUN JUL 29 2012/
AVIATION...00Z TAFS.
UNSTABLE AIR MASS OVER THE FA WITH THUNDERSTORMS ALONG THE CANADIAN
BORDER AND OVER WESTERN LAKE SUPERIOR ATTM. WILL EXPECT TO SEE
ADDITIONAL DEVELOPMENT WITH THE APPROACHING FRONT IN EASTERN ND.
ATTEMPTED TO TIME STORMS THROUGH THE TAF SITES. ANTICIPATE VFR
THROUGH THE FORECAST CYCLE...EVEN IN THE VCNTY OF STORMS AS THEY
REMAIN FAIRLY ELEVATED. LLWS IS POSSIBLE NEAR SUNRISE AT
DLH/HIB/BRD UNTIL ABOUT 15Z WHEN FROPA TURNS THE SFC WIND TO THE
NW AND BECOMES GUSTY.
PREV DISCUSSION... /ISSUED 319 PM CDT SUN JUL 29 2012/
SHORT TERM...
AN H85 TROUGH ASSOCIATED WITH H50 VORT MAX CURRENTLY SEEN ON IR SAT
IMAGERY ROTATING OVER SRN MANITOBA...WILL REMAIN THE FOCUS FOR
SHRA/TSTMS TONIGHT THROUGH MONDAY MORNING. CURRENT RADAR TRENDS
SHOW A WELL ORGANIZED AREA OF STORMS OVER ONTARIO...TRACKING SW
INTO THE MINNESOTA ARROWHEAD. AT THIS TIME THE STRONGEST STORMS
ARE LOCATED TO THE NORTH OF THE INTERNATIONAL BORDER.
HOWEVER...INSTABILITY IS QUITE HIGH WITH THE LATEST SPC
MESO ANALYSIS SHOWING 3000 J/KG MUCAPE AND INCREASING 0-1KM SHEAR
ACROSS THE NRN ZONES.
MODELS ARE IN GOOD AGREEMENT THAT THE DIGGING TROUGH PUSHES INTO
NW MN AROUND 06Z TONIGHT...TRACKING ACROSS NE MN AND OVER LAKE
SUPERIOR THROUGH MONDAY AFTERNOON. A 100 KT H25 CYCLONICALLY
CURVED JET OVER SOUTHERN MN WILL PLACE THE ZONES IN A REGION OF
INCREASING UPPER LEVEL DIVERGENCE OVERNIGHT...PROVIDING ADDITIONAL
SUPPORT FOR CONVECTION. THE BULK OF THE PRECIP WILL BE FOUND NEAR
THE SFC REFLECTION LOW THAT WILL TRACK EAST ALONG THE
INTERNATIONAL BORDER INTO ONTARIO BY MONDAY MORNING. HAVE KEPT
LIKELY POPS GOING ACROSS IRON RAGE/ARROWHEAD REGION WHERE A HALF
TO ONE INCH OF RAIN IS EXPECTED THROUGH MONDAY. DECREASING RAIN
CHANCES ARE FOUND SOUTH OF THE HIGHWAY 2 CORRIDOR. ALTHOUGH
SOUNDINGS SHOW INSTABILITY AND CAPE VALUES REMAIN HIGH IN THE
KBRD/KDLH/KHYR AREAS...THERE REMAINS UNCERTAINTY HOW FAR SOUTH
ALONG THE SFC TROUGH INTO THE DRY AIR STORMS WILL DEVELOP LATE
TONIGHT.
KEPT 20 POPS FOR A FEW ADDITIONAL STORMS MONDAY AFTERNOON ON THE
BACKSIDE OF THE LOW WITH STEEP LAPSE RATES...ELEVATED SBCAPE AND
LINGERING MID LEVEL MOISTURE.
LONG TERM...TUESDAY THROUGH SATURDAY NIGHT...
SURFACE HIGH PRESSURE IN PLACE ACROSS THE UPPER MIDWEST TUESDAY WILL
KEEP MUCH OF THE REGION DRY AND WARM EARLY IN THE EXTENDED PERIOD.
THE NEXT UPPER WAVE AND SFC TROUGH WILL MOVE THROUGH NRN MN ON
WEDNESDAY AND SPREAD SHOWERS AND THUNDERSTORMS ACROSS THE NORTHLAND
THROUGH THE DAY...WITH THE BEST CHANCE OF PRECIP NORTH OF HIGHWAY 2.
THE ACTIVE PATTERN WILL CONTINUE THURSDAY THROUGH SATURDAY AS THE
LARGE UPPER RIDGE OVER THE CENTRAL US SUBSIDES AND QUASI-ZONAL FLOW
SETS UP ACROSS THE NRN PLAINS/UPPER MIDWEST. A SERIES OF FAST MOVING
SHRT WVS WILL TRANSITION THROUGH THE AREA AND BRING SCATTERED
SHOWERS AND STORMS. WILL LIKELY SEE A BREAK IN THE ACTIVE WEATHER
PATTERN INTO THE LATTER HALF OF THE WEEKEND. TEMPERATURES WILL
REMAIN WARM TUESDAY THROUGH THURSDAY WITH HIGHS IN THE LOW TO MID
80S AND OVERNIGHT LOWS IN THE LOWER 60S. BY FRIDAY AND INTO THE
WEEKEND...A SLIGHTLY COOLER AIR MASS MOVES IN FROM THE NORTH AND
ALLOWS DAYTIME HIGHS TO DROP INTO THE LOWER TO MID 70S...WITH NIGHT
TIME LOWS IN THE LOWER TO MID 50S THIS WEEKEND.
&&
.POINT TEMPS/POPS...
DLH 62 83 62 83 / 10 10 10 40
INL 58 84 63 83 / 10 10 10 50
BRD 61 85 65 87 / 0 0 10 30
HYR 63 85 60 85 / 10 10 10 30
ASX 63 83 62 86 / 10 10 10 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
349 PM CDT MON JUL 30 2012
.SHORT TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TONIGHT)
EXTENSIVE AREA OF MID AND HIGH CLOUDS HAVE HELPED HOLD TEMPERATURES
BACK OVER MOST OF THE REGION TODAY. SURFACE REPORTS FROM THE LARGE
AREA OF RETURNS ON RADAR ARE MAINLY SPRINKLES. THIS IS BEING
GENERATED BY A VORT MAX THAT WILL MOVE SOUTH INTO THE SOUTHERN CWA
BY 00Z. THERE IS LITTLE LOW LEVEL FORCING ASSOCIATED WITH IT
ACCORDING TO THE RAP UNTIL AFTER 00Z...AND EVEN THEN IT IS QUITE
WEAK. THINK GOING SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS STILL
LOOKS OKAY GIVEN SLIGHTLY BETTER LOW LEVEL FORCING AND MORE
INSTABILITY. OTHERWISE CHANCES SHOULD DECREASE WITH TIME AS THE
LOW MOVES FARTHER SOUTH.
BRIIT
&&
.LONG TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TUESDAY THROUGH NEXT MONDAY)
MAIN CONCERN ONCE AGAIN IS HEAT. HAVE ISSUED A HEAT ADVISORY JUST
FOR THE ST. LOUIS METRO AREA ON TUESDAY AFTERNOON AS IT CURRENTLY
LOOKS LIKE HEAT INDEX READINGS WILL CLIMB TO AROUND 105 DURING THE
AFTERNOON.
GFS/NAM ARE IN RELATIVELY GOOD AGREEMENT THAT A WEAK COLD FRONT WILL
BE MOVING SOUTH OUT OF THE UPPER MIDWEST INTO NORTHERN MISSOURI AND
CENTRAL ILLINOIS AROUND MIDDAY TOMORROW. DO NOT EXPECT MUCH CLOUDS
AND ANY RAIN CHANCES WITH THIS FRONT AS WE WILL LIE UNDER SUBSIDENCE
BETWEEN A SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES AND A
VORT MAX MOVING ACROSS SOUTHWEST MISSOURI. NAM FORECAST SOUNDINGS
SHOWING DEEP MIXING TO 700MB AHEAD OF THE FRONT WHICH SUPPORTS
GOING HIGHS WHICH ARE CLOSE TO THE NAM MOS TEMPERATURES WHICH HAVE
VERIFIED BETTER THIS SUMMER. DEWPOINTS SHOULD FALL INTO THE UPPER
50S TO LOWER 60S WITH THE MIXING...WHICH COMBINED WITH HIGHS
RISING TO AROUND 104 RESULT IN HEAT INDEX HIGHS BRIEFLY REACHING
105 TOMORROW AFTERNOON. TEMPERATURES ON WEDNESDAY LOOK TO BE NOT
AS WARM BEHIND THE FRONT...SO HEAT INDEX READINGS ARE EXPECTED TO
STAY BELOW 100 DEGREES. ANOTHER FRONT MOVES INTO NORTHERN MISSOURI
LATE THURSDAY/THURSDAY NIGHT...WITH THE GFS BRINGING IT THROUGH
THE AREA AND THE ECMWF KEEPING IT STALLED TO THE NORTH AS THE
UPPER FLOW BECOMES ZONAL. HAVE GONE WITH JUST A SLIGHT CHANCE FOR
SHOWERS/STORMS ON THURSDAY AND TEMPERATURES IN THE UPPER 90S WHICH
SHOULD RESULT IN HEAT INDEX READINGS BETWEEN 98-103.
GENERALLY STAYED WITH THE ECMWF OVER THE WEEKEND. SHOULD BE SOME
INCREASE IN LOW LEVEL FORCING AHEAD OF A COLD FRONT THAT WILL MOVE
ACROSS THE AREA ON SUNDAY...SO HAVE KEPT A CHANCE OF SHOWERS AND
THUNDERSTORMS GOING AHEAD OF IT. WITH 850MB TEMPS STAYING ABOVE
20C...HIGH TEMPERATURES SHOULD REMAIN ABOVE 90 THROUGH THE PERIOD.
BRITT
&&
.AVIATION...
ISSUED AT 1236 PM CDT MON JUL 30 2012
VFR CONDITIONS EXPECTED AT ALL TAF SITES THROUGH THE FORECAST
PERIOD. WEAK LOW PRESSURE TO THE SOUTH OF KSTL WILL CONTINUE
MOVING SOUTHEASTWARD TODAY INTO TONIGHT. A FEW SPRINKLES ARE
POSSIBLE AT KUIN THROUGH AROUND 00Z AS AN UPPER LEVEL DISTURBANCE
MOVES THROUGH. A WEAK FRONT WILL APPROACH KUIN TAF SITE BY AROUND
12Z...THEN CONTINUE TO SINK TO THE SOUTH REACHING KSTL BY AROUND
18Z. NORTHWEST TO NORTH WINDS WILL INCREASE BEHIND THE
FRONT...HOWEVER NO PRECIPITATION IS EXPECTED.
SPECIFICS FOR KSTL...VFR CONDITIONS WILL CONTINUE...AS ONLY HIGH
CLOUDS ARE EXPECTED FOR THE REMAINDER OF THE DAY. SLOW CLEARING
SHOULD BEGIN AFTER SUNSET. LIGHT NORTH WINDS WILL BECOME VARIABLE
NEAR SUNSET...THEN INCREASE BY LATE TUESDAY MORNING AS A FRONT
APPROACHES.
BROWNING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR JEFFERSON MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR MADISON IL-
MONROE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
333 PM CDT MON JUL 30 2012
.DISCUSSION...
MOISTURE AS INDICATED ON SFC OBS SHOWING DEW PTS IN THE 60S AND
SATELLITE TPW PRECIPITABLE WATER ESTIMATES NEAR 1.3 INCHES OR HIGHER
ACROSS SWRN NEB WOULD SUGGEST A REASONABLE CHANCE OF TSTMS GIVEN
THE WEAK DISTURBANCE MOVING THROUGH NRN COLO THIS AFTN. HOWEVER
THE HRRR AND THE RAP MODELS ARE VERY QUIET GENERATING LIMITED CONVECTIVE
ACTIVITY ACROSS THE HIGH PLAINS. THIS COULD BE THE RESULT OF WEAK
UPSLOPE ADVECTION...A MID LEVEL SUBSIDENCE/CAP AND WEAK STEERING
CURRENTS. MEANWHILE THE KLNX VWP INDICATES A VERY DEEP BUT WEAK
EAST WINDS EXTENDING ALL THE WAY TO 12 KFT ASL.
THE FCST THIS EVENING CALLS FOR ISOLATED STORMS GENERALLY ALONG
AND WEST OF HIGHWAY 61. WE WILL CONTINUE TO CLOSELY MONITOR THE
CONVECTION DEVELOPING IN COLO AND OBVIOUS DEEP MOISTURE PLUME
ACROSS SWRN NEB. UPSLOPE FLOW MAY INCREASE LATE THIS AFTN AND
EARLY THIS EVENING ENHANCING CONVERGENCE. THE MODERATE CU FORMING
SOUTH OF THE WEATHER OFFICE AND CIGS NEAR 5 KFT AT HOLYOKE SUGGEST
ATLEAST SOME POTENTIAL FOR ORGANIZED STORM DEVELOPMENT IF THE
DISTURBANCE ACROSS COLO CAN REACH SWRN NEB BY EARLY EVENING.
ON TUESDAY...LOW PRESSURE WILL BEGIN TRACKING THROUGH THE NRN
PLAINS WHILE HIGH PRESSURE CONTINUES ACROSS ERN NEB. THIS SHOULD
PRODUCE COOLER TEMPS SOUTH AND EAST IN THE SOUTH-SOUTHEAST WIND
AREA AND VERY WARM TEMPS ACROSS THE NW ZONES WHERE DOWN SLOPING
SOUTHWEST WINDS MAY DEVELOP. THE MOISTURE PLUME BECOMES DIFFUSE
AND LESS FOCUSED AS IT IS DRAWN NORTH IN ALL MODELS EXCEPT THE GFS
WHICH EXPLODES WEDNESDAY EVENING OVER SRN SD/NCNTL NEB AS A COLD
FRONT APPROACHES THE FCST AREA. THE FATE OF THIS MOISTURE PLUME
THE POTENTIAL FOR DESPERATELY NEEDED RAINFALL MIGHT BEST BE
HANDLED INSIDE 12 HRS. THE OTHER MODELS ARE NOT GENERATING MUCH
QPF...POSSIBLY THE RESULT OF WARM MIDLEVEL LAPSE RATES.
A WEAK AREA OF COOLER HIGH PRESSURE WILL BUILD BEHIND THE FRONT
THURSDAY AND TEMPS SHOULD SETTLE BACK IN TO THE 90S AFTER HIGHS
AROUND 100 WEDNESDAY. ALL MODELS ARE IN GOOD AGREEMENT THAT A DEEP
DISTURBANCE WILL MOVE THROUGH NRN HIGH PLAINS FRIDAY. THIS SYSTEM
SHOULD PRODUCE STRONG SOUTHWEST WINDS WITH TEMPERATURES RISING TO
OR ABOVE 100F IN MANY AREAS. A POWERFUL COLD FRONT WILL SWEEP
THROUGH FRIDAY NIGHT AND COOL TEMPS BACK INTO THE 80S FOR SATURDAY.
THE ECM HOLDS COOL HIGH PRESSURE INPLACE SUNDAY WHILE THE GFS IS
OFF TO THE RACES DEEPENING LOW PRESSURE ACROSS THE NRN HIGH PLAINS.
THE ECM IS PREFERRED FOR HIGHS IN THE LOWER 90S. BOTH MODELS ARE
SHOWING A STRONG THERMAL RIDGE ACROSS THE HIGH PLAINS MONDAY. THIS
SHOULD EASILY PRODUCE HIGHS IN THE UPPER 90S.
THE UPPER LEVEL RIDGE AND ASSOCIATED SFC HEAT LOW SHOULD REMAIN
ACROSS THE SRN HIGH PLAINS AND MID SOUTH DURING THE NEXT 7 DAYS.
THE ECM IS TRYING TO AMPLIFY THE RIDGE INTO THE CENTRAL PLAINS BY
NEXT MONDAY. RAIN CHANCES ARE GENERALLY CONFINED TO THE NORTH AND
EAST LATE FRIDAY WITH THE APPROACHING COLD FRONT. A WEAK
DISTURBANCE CROSSING ERN WY AND THE BLACK HILLS THURSDAY MAY BE
THE CATALYST FOR ISOLATED STORMS LATE IN THE DAY OR AT NIGHT
ACROSS MUCH OF THE FCST AREA. THE REST OF THE FCST...SATURDAY THROUGH
MONDAY...IS DRY.
BE AWARE THAT THE ONLY REAL HOPE FOR RAINFALL DURING THE NEXT 4
DAYS LIES IN THE FATE OF THE MOISTURE PLUME ACROSS SRN NEB THIS
AFTERNOON. THERE REMAINS A VAST AREA OF VERY DRY AIR AT THE
SURFACE AND LOWER LEVELS OF THE ATM. IN FACT THE WATER VAPOR
PAIRED WITH THE TPW PRODUCT SHOW A TREMENDOUS SURGE OF DRY AIR
FEEDING IN OFF THE PACIFIC THROUGH NEVADA...ID AND MT.
&&
.AVIATION...
18Z TAF ISSUANCE...SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
TO FORM OVER THE HIGH PLAINS OF COLORADO/WYOMING ONCE AGAIN THIS
AFTERNOON...AND POSSIBLY SPREAD EAST ACROSS PORTIONS OF WESTERN AND
SOUTHWEST NEBRASKA THIS EVENING/TONIGHT. MODEL GUIDANCE INDICATES
THIS ACTIVITY POSSIBLY AS FAR EAST AS KOGA AND KIML BUT GIVEN THAT
THE LOWER LEVELS OF THE ATMOSPHERE REMAIN DRY...VISIBILITY AND/OR
CIGS RESTRICTIONS ARE NOT ANTICIPATED. THE MAIN THREAT FROM ANY
STORM THAT DEVELOPS WILL BE GUSTY ERRATIC WIND. OTHERWISE...WIND
SPEEDS WILL REMAIN LIGHT AND VARIABLE THROUGH MID MORNING TOMORROW.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS/CDC
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
623 AM CDT MON JUL 30 2012
.AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK
VFR CONDITIONS ARE EXPECTED THRU THE TAF PERIOD. SFC WINDS WILL BE
AROUND OR LESS THAN 5 KTS...GENERALLY FROM THE EAST. A WEAK FRONT
WILL DROP INTO NORTHEAST NEBRASKA LATE THIS AFTERNOON. A FEW
SHOWERS OR THUNDERSTORMS COULD DEVELOP ALONG THIS BOUNDARY. THIS
WOULD MAINLY AFFECT KOFK...BUT DUE TO UNCERTAINTY...WILL LEAVE OUT
OF THE TERMINAL FOR NOW.
KERN
&&
.PREV DISCUSSION... /ISSUED 335 AM CDT MON JUL 30 2012/
DISCUSSION...
TEMPERATURES AND PCPN CHANCES THE NEXT SEVERAL DAYS WILL PROVIDE THE
MAIN FORECAST CHALLENGES.
HIGHS YESTERDAY ENDED UP A LITTLE HOTTER THAN EXPECTED...ESPECIALLY
CENTRAL AND SOUTHERN ZONES. 00Z KOAX SOUNDING SHOWED MIXING UP TO
AROUND 825 MB AND EVEN A SMALL SUPERADIABATIC LAYER NEAR THE SURFACE.
OVERALL PATTERN IS SIMILAR TO YESTERDAY...BUT SUBTLE DIFFERENCES. AT
300 MB...JETSTREAM STILL STRETCHED FROM NEVADA INTO THE DAKOTAS...
THEN DIVED SOUTHEAST INTO THE OHIO VALLEY. A JET MAX OF AROUND 85 KTS
WAS NOTED OVER NORTHWEST NORTH DAKOTA AT 00Z. THIS APPEARED TO HAVE
SHIFTED INTO EASTERN SOUTH DAKOTA BY 06Z ACCORDING TO LATEST NAM12
AND RAP MODELS. CENTER OF RIDGE AT 700 MB AND 500 MB WAS LOCATED
OVER THE SOUTHERN PART OF THE TEXAS PANHANDLE. MONSOONAL MOISTURE
WAS WORKING ITS WAY NORTH INTO THE ROCKIES...THEN EASTWARD THROUGH
THE CENTRAL PLAINS. A MESOSCALE CONVECTIVE SYSTEM THAT DEVELOPED
OVER NORTHEAST COLORADO LAST EVENING CONTINUED TO MOVE EAST
ACROSS NORTHERN KANSAS AND SOUTHERN NEBRASKA EARLY THIS MORNING.
WILL MAINTAIN AREAL COVERAGE WORDING FOR OUR SOUTHERN ZONES INTO
MID MORNING...WHEN MCS MAY START TO WEAKEN. OTHERWISE...WILL HAVE
A SLIGHT CHANCE OF THUNDERSTORMS MOST AREAS UNTIL 18Z THEN
MAINTAIN LOW POPS MUCH OF THE FORECAST AREA THIS AFTERNOON. FELT
CLOUDS MAY HOLD HIGHS BACK SOME TODAY...SO WENT WITH MID TO UPPER
90S NORTH AND LOWER TO MID 90S SOUTH. SOME STORMS COULD POP UP
LATE THIS AFTERNOON OR EARLY EVENING NEAR A FRONTAL BOUNDARY THAT
PUSHES DOWN FROM THE NORTHERN PLAINS.
CENTER OF THE 500 MB RIDGE LOCATION DOES NOT CHANGE MUCH THROUGH
MID WEEK...AND SO MID LEVEL MOISTURE WILL BE ONE THING TO KEY ON
FOR CONVECTIVE POTENTIAL. HAVE A MAINLY DRY FORECAST GOING FROM
LATE THIS EVENING INTO TUESDAY EVENING. 00Z ECMWF SHOWS ANOTHER
PRETTY GOOD INCREASE IN 700 MB DEWPOINTS INTO THE AREA FOR LATE
TUESDAY NIGHT AND WEDNESDAY...SO SPREAD THUNDERSTORM CHANCES FROM
WEST TO EAST DURING THAT TIME.
LATER IN THE WEEK...A FAIRLY STRONG SHORTWAVE TROUGH DIGS OVER THE
NORTHERN ROCKIES THURSDAY...THEN MOVES INTO THE NORTHERN PLAINS BY
FRIDAY NIGHT. THIS SHOULD PUSH A FRONT THROUGH THE REGION FRIDAY
NIGHT OR SATURDAY. TEMPERATURES AHEAD OF THE FRONT SHOULD TOP OUT
MAINLY IN THE 90S TO AROUND 100 THROUGH THE WEEK. HIGHS BY SATURDAY
AND SUNDAY COULD COOL TO THE UPPER 80S/LOWER 90S. ALTHOUGH THE
FRONTAL PASSAGE SUGGESTS A DECENT CHANCE OF PCPN...MODELS DO NOT
AGREE ON QPF...SO WILL NOT GET TOO OPTIMISTIC AT THIS POINT.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
335 AM CDT MON JUL 30 2012
.DISCUSSION...
TEMPERATURES AND PCPN CHANCES THE NEXT SEVERAL DAYS WILL PROVIDE THE
MAIN FORECAST CHALLENGES.
HIGHS YESTERDAY ENDED UP A LITTLE HOTTER THAN EXPECTED...ESPECIALLY
CENTRAL AND SOUTHERN ZONES. 00Z KOAX SOUNDING SHOWED MIXING UP TO
AROUND 825 MB AND EVEN A SMALL SUPERADIABATIC LAYER NEAR THE SURFACE.
OVERALL PATTERN IS SIMILAR TO YESTERDAY...BUT SUBTLE DIFFERENCES. AT
300 MB...JETSTREAM STILL STRETCHED FROM NEVADA INTO THE DAKOTAS...
THEN DIVED SOUTHEAST INTO THE OHIO VALLEY. A JET MAX OF AROUND 85 KTS
WAS NOTED OVER NORTHWEST NORTH DAKOTA AT 00Z. THIS APPEARED TO HAVE
SHIFTED INTO EASTERN SOUTH DAKOTA BY 06Z ACCORDING TO LATEST NAM12
AND RAP MODELS. CENTER OF RIDGE AT 700 MB AND 500 MB WAS LOCATED
OVER THE SOUTHERN PART OF THE TEXAS PANHANDLE. MONSOONAL MOISTURE
WAS WORKING ITS WAY NORTH INTO THE ROCKIES...THEN EASTWARD THROUGH
THE CENTRAL PLAINS. A MESOSCALE CONVECTIVE SYSTEM THAT DEVELOPED
OVER NORTHEAST COLORADO LAST EVENING CONTINUED TO MOVE EAST
ACROSS NORTHERN KANSAS AND SOUTHERN NEBRASKA EARLY THIS MORNING.
WILL MAINTAIN AREAL COVERAGE WORDING FOR OUR SOUTHERN ZONES INTO
MID MORNING...WHEN MCS MAY START TO WEAKEN. OTHERWISE...WILL HAVE
A SLIGHT CHANCE OF THUNDERSTORMS MOST AREAS UNTIL 18Z THEN
MAINTAIN LOW POPS MUCH OF THE FORECAST AREA THIS AFTERNOON. FELT
CLOUDS MAY HOLD HIGHS BACK SOME TODAY...SO WENT WITH MID TO UPPER
90S NORTH AND LOWER TO MID 90S SOUTH. SOME STORMS COULD POP UP
LATE THIS AFTERNOON OR EARLY EVENING NEAR A FRONTAL BOUNDARY THAT
PUSHES DOWN FROM THE NORTHERN PLAINS.
CENTER OF THE 500 MB RIDGE LOCATION DOES NOT CHANGE MUCH THROUGH
MID WEEK...AND SO MID LEVEL MOISTURE WILL BE ONE THING TO KEY ON
FOR CONVECTIVE POTENTIAL. HAVE A MAINLY DRY FORECAST GOING FROM
LATE THIS EVENING INTO TUESDAY EVENING. 00Z ECMWF SHOWS ANOTHER
PRETTY GOOD INCREASE IN 700 MB DEWPOINTS INTO THE AREA FOR LATE
TUESDAY NIGHT AND WEDNESDAY...SO SPREAD THUNDERSTORM CHANCES FROM
WEST TO EAST DURING THAT TIME.
LATER IN THE WEEK...A FAIRLY STRONG SHORTWAVE TROUGH DIGS OVER THE
NORTHERN ROCKIES THURSDAY...THEN MOVES INTO THE NORTHERN PLAINS BY
FRIDAY NIGHT. THIS SHOULD PUSH A FRONT THROUGH THE REGION FRIDAY
NIGHT OR SATURDAY. TEMPERATURES AHEAD OF THE FRONT SHOULD TOP OUT
MAINLY IN THE 90S TO AROUND 100 THROUGH THE WEEK. HIGHS BY SATURDAY
AND SUNDAY COULD COOL TO THE UPPER 80S/LOWER 90S. ALTHOUGH THE
FRONTAL PASSAGE SUGGESTS A DECENT CHANCE OF PCPN...MODELS DO NOT
AGREE ON QPF...SO WILL NOT GET TOO OPTIMISTIC AT THIS POINT.
MILLER
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDS ARE EXPECTED THROUGH THE PERIOD. MID AND HIGH LVL CLOUDS
HAVE BEEN INCREASING AT ALL THE TAF SITES AND THIS WILL CONT THROUGH
THE OVERNIGHT HOURS. SCT SHRA TO THE WEST ASSOCIATED WITH A WEAK
SHRTWV TROUGH WILL CONT TO ADVANCE EWD AND WL INCLUDE SOME VC
SHOWERS AT LNK FOR LATE TONIGHT AND INTO MON MRNG...BUT THIS WILL
LIKELY REMAIN S OF OMA/OFK. OTHERWISE LIGHT WINDS ARE EXPECTED THRU
THE PERIOD WITH WEAK SFC RIDGE OVER THE AREA.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
719 AM EDT MON JUL 30 2012
.SYNOPSIS...
A STATIONARY FRONT OVER EASTERN NORTH CAROLINA WILL WEAKEN TODAY. A
SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE SOUTHEAST THROUGH THE
REGION THROUGH WEDNESDAY. UPPER LEVEL HIGH PRESSURE BUILDS OVER THE
REGION FROM THE WEST LATER IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 AM MONDAY...
TODAY...
WATER VAPOR IMAGERY THIS MORNING CONTINUES TO SHOW CONVECTIVELY
ENHANCED UPPER LEVEL DISTURBANCES MOVING SOUTHEAST OUT OF THE
UPPER MIDWEST...BETWEEN AN UPPER RIDGE OVER THE INNER MOUNTAIN
WEST AND A BROAD TROUGH OVER THE EASTERN US. THE MOST NOTABLE
DISTURBANCE APPROACHING THE CAROLINAS IN THE SHORT TERM IS
CURRENTLY NEAR THE IN/KY BORDER. THIS DISTURBANCE IS FORECAST TO
DEEPEN THE UPPER TROUGH AS IT SWINGS ACROSS NORTHERN GA AND SC
LATER TODAY. MODELS INDICATE THE LOW LEVEL WINDS WILL BACK IN
RESPONSE TO THE DEEPENING TROUGH...LEADING TO WEAK WARM
ADVECTION/VEERING PROFILE AND CONVECTIVE INITIATION ALONG A
STALLED OUT THE COLD FRONT OVER THE COASTAL PLAIN. WITH DEWPOINTS
HAVING RECOVERED INTO THE LOWER 70S AND PW UP TO 2 INCHES EAST OF
THE BOUNDARY BUT WEAK MID LEVEL LAPSE RATES...A MODEL CONSENSUS
GIVES 1000 TO MAYBE 1500 J/KG OF MLCAPE OVER THE COASTAL PLAIN AND
LESS TO THE WEST. THE WEAK CINH ON THE 00Z KMHX RAOB SHOULD ERODE
QUICKLY WITH HEATING LATER THIS MORNING AND HRRR SHOWS ISOLATED
CONVECTION AS EARLY AS 15-16Z AROUND SAMPSON/WAYNE COUNTY. WE WILL
SHOW POPS INCREASING WESTWARD DURING THE AFTERNOON AS THE
SOUTHEASTERLY FLOW AND ANY OUTFLOW OF SHOWERS/STORMS WILL HELP
SHIFT THE REMNANTS OF THE FRONT AND LOW LEVEL FOCUS WESTWARD.
HOWEVER...BASED ON THE 00Z KGSO RAOB AND FORECAST
SOUNDINGS...SHOWERS AND STORMS WILL ENCOUNTER A MORE PRONOUNCED
MID LEVEL CAP OVER THE WESTERN PIEDMONT..SO WE WILL KEEP POPS AT
SLIGHT CHANCE OVER MUCH OF THE WESTERN CWA. DEEP LAYER FLOW WILL
BE WEAK TODAY..SO ANY HAZARDOUS WEATHER WILL BE FROM PULSING
STRONGER STORMS AND AN ISOLATED PRECIP LOADED DOWNBURST.
GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH HIGHS RIGHT AT
NORMAL VALUES...88-90
TONIGHT...
MODELS SHOW A WEAK SURFACE WAVE DEVELOPING OVER THE COASTAL PLAIN
BENEATH WEAK HEIGHT FALLS ALOFT. A RELATIVELY STRONG 35KT 850MB JET
IS FORECAST TO DEVELOP OFFSHORE...WHICH IS WHERE MOST OF THE
OVERNIGHT SHOWERS AND STORMS WILL BE FOCUSED. THUS...THERE SHOULD BE
LITTLE IMPACTS ON SENSIBLE WEATHER FOR CENTRAL NC..OTHER THAN A
LIGHT NORTHEASTERLY WIND AND POSSIBLY SOME PATCHY STRATUS BY TUESDAY
MORNING. LOWS IN THE LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 310 AM MONDAY...
THE TRAIN OF UPPER LEVEL DISTURBANCES FROM THE UPPER MIDWEST TO THE
SOUTHERN APPALACHIANS WILL CONTINUE ON TUESDAY...AS MODELS SHOW A
80KT SPEED MAX AND ASSOCIATED VORTICITY DIVING TOWARD WESTERN NC AND
UP STATE SC BY EARLY AFTERNOON. MODELS INDICATE SOME CONVECTION OVER THE
MOUNTAINS AND ALONG THE COAST BY LATE MORNING...BUT A SHARPENING OF
THE MID/UPPER LEVEL TROUGH AXIS ASSOCIATED WITH THE AFOREMENTIONED UPPER
DISTURBANCE SHOULD LEAD TO SCATTERED SHOWERS AND STORMS OVER THE
WEST BY EARLY AFTERNOON. THE SEVERE THREAT OVER CENTRAL NC IS
SOMEWHAT UNCERTAIN AS THE STRONGER EFFECTIVE DEEP LAYER SHEAR WILL
LIKELY LIE TO THE SOUTHWEST OF THE CWA IN CLOSER PROXIMITY TO THE
BELT OF STRONGER MID LEVEL FLOW AND A FAIRLY STRONG SURFACE REFLECTION.
HOWEVER...IF STORMS CAN GET GOING OVER THE WESTERN AND SOUTHERN
PIEDMONT...THEN THERE WOULD BE A LOWER END THREAT OF DAMAGING WIND
GUSTS WITH STRONGER STORMS AND/OR MERGING COLD POOLS. WE WILL SHOW
HIGHEST POPS SHIFTING FROM THE SOUTHWEST TO EASTERN AREAS DURING THE
AFTERNOON AND EVENING...TRENDING DOWN TO A SLIGHT CHANCE OVERNIGHT.
WITH WEAK FLOW OVER CENTRAL NC DURING THE DAY AND NEAR MAXIMUM
INSOLATION...HIGHS SHOULD TOP OUT IN THE 86-90 RANGE BASED ON A
FORECAST 12Z LOW LEVEL THICKNESS OF 1405M. LOWS TUESDAY NIGHT ONCE
AGAIN IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
WEDNESDAY AND WEDNESDAY NIGHT...A MID-LEVEL TROUGH REMAINS OVER
CENTRAL NORTH CAROLINA...AND BOTH THE GFS AND THE NAM FORECAST AN
850MB TROUGH MOVING GRADUALLY WEST TO EAST ACROSS CENTRAL NORTH
CAROLINA THROUGH THE EVENING. THE NAM IS FARTHER SOUTH IN THE TRACK
OF THE 850MB WAVE AS COMPARED TO THE GFS...THOUGH BOTH FORECAST A
WEAK SURFACE WAVE MOVING OVER OR NEAR THE SANDHILLS AND THE SOUTHERN
COASTAL PLAIN AND TOWARD THE COAST WEDNESDAY AFTERNOON THROUGH
WEDNESDAY NIGHT. WITH 850MB THETA-E RIDGING FORECAST BY THE GFS
DURING THE DAY...AND THE APPROACH OF A WEAK 50KT JETLET AT 250MB
FROM THE NORTHWEST AIDING IN UPPER DIFFLUENCE...EXPECT AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING OVER MUCH OF CENTRAL
NORTH CAROLINA DURING THE DAY. THE GREATER CHANCES WILL BE TOWARD
INTERSTATE 95...IN VICINITY OF DEEPER MOISTURE WHERE PRECIPITABLE
WATER VALUES WILL BE AROUND 1.75 INCHES...AS COMPARED TO 1.5 INCHES
TOWARD THE YADKIN RIVER. IT SHOULD BE NOTED THAT THE GFS BUFR
SOUNDINGS ARE STABLE IN COMPARISON TO THE NAM BUFR SOUNDINGS...
DESPITE THE FACT THE GFS HAS THE 850MB TROUGH FARTHER NORTH AND ITS
QPF IS GREATER THAN THE NAM. 0-6KM SHEAR IS AROUND 25KT...NOT TOO
BAD COMPARED TO MANY RECENT DAYS...AND MLCAPE IS FORECAST AROUND
2000J/KG DURING WEDNESDAY AFTERNOON. ALTHOUGH A SURFACE WAVE IS
FORECAST TO MOVE OVER OR VERY CLOSE TO THE AREA...ESPECIALLY TO THE
SOUTHEAST...0-3KM HELICITY VALUES ARE FAIRLY SMALL OVER CENTRAL
NORTH CAROLINA...ONLY RISING TO NEAR 100M2/S2 TOWARD AND OFFSHORE OF
THE CAROLINA COAST. IF ANY ISOLATED SEVERE STORMS WOULD DEVELOP...
CURRENT THOUGHTS ARE THE BETTER CHANCE WOULD BE FROM ABOUT U.S. 1
EASTWARD.
BEHIND THE SURFACE AND 850MB WAVES...THE OVERALL AIR MASS DRIES ON
BUFR SOUNDINGS OVERNIGHT WEDNESDAY. HOWEVER...BUFR SOUNDINGS FROM
BOTH THE NAM AND THE GFS SHOW SLIGHT LAYER COOLING ABOVE 700MB...
AND THE GFS FORECASTS FAIRLY ROBUST POTENTIAL VORTICITY ON THE 1.5
PVU SURFACE MOVING INTO CENTRAL NORTH CAROLINA LATE AT NIGHT IN THE
NORTHWEST FLOW ALOFT. POSSIBLY FOR THESE REASONS BOTH THE NAM AND
GFS FORECAST LIGHT QPF OVER THE PIEDMONT OVERNIGHT...AND WILL
MAINTAIN A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM DUE TO THE
SLIGHT POTENTIAL FOR WHAT SHOULD BE ELEVATED...DEEP CONVECTION.
FOLLOWED A BLEND OF THE MET AND MAV MOS AND THE BIAS CORRECTED MOS
GUIDANCE FOR WEDNESDAY WITH HIGHS AROUND 90...AND EXPECT OVERNIGHT
LOWS WEDNESDAY AROUND 70.
FROM THURSDAY THROUGH THE END OF THE WEEK...LONG-TERM GUIDANCE
CONSENSUS IS FOR HEIGHTS TO INCREASE OVER AND AROUND CENTRAL NORTH
CAROLINA...AS RIDGING BUILDS EAST FROM THE PLAINS AND...PROBABLY
MORE SO...INFLUENCED BY RIDGING OVER THE NORTH ATLANTIC. DESPITE THE
RIDGING ALOFT...RELATIVE TROUGHINESS SHOULD REMAIN IN THE FLOW ALOFT
OVER THE MID-ATLANTIC. THE RESULT SHOULD BE LIGHT...BUT BROADLY
DIFFLUENT FLOW ALOFT. 1000-850MB THICKNESSES SHOULD WARM...LEADING
TO HIGHS MOST DAYS IN THE LOWER TO MID 90S...AND A FEW UPPER 90S
CANNOT BE COMPLETELY RULED OUT ESPECIALLY OVER THE SOUTHWEST
PIEDMONT...SANDHILLS...AND U.S. 1 CORRIDOR. CURRENTLY FORECAST DEW
POINTS LEAD TO HEAT INDICES AT THE END OF THE WEEK BETWEEN 100 AND
105 DEGREES...HIGHEST SATURDAY AND SUNDAY.
ALL OF THE LONG-TERM GUIDANCE SUGGESTS PERIODIC PASSAGE OF WEAK
MID-LEVEL DISTURBANCES IN THE BROADLY DIFFLUENT WEST-NORTHWEST FLOW
ALOFT. THE TIMING OF THESE...AND HOW THEY ARE INFLUENCED BY DEEP
CONVECTION UPSTREAM...IS DIFFICULT TO FORECAST IN THE LONG TERM. THE
COMBINATION OF SEA BREEZE AND PIEDMONT TROUGH INFLUENCES FOR
LOW-LEVEL LIFT...AND MID-LEVEL SHORTWAVES IN A MODESTLY MOIST AND
UNSTABLE AIR MASS...SHOULD RESULT IN ISOLATED TO SCATTERED CHANCES
FOR SHOWERS AND THUNDERSTORMS...GENERALLY DIURNALLY...EACH DAY. THE
LATEST GFS FORECASTS PRECIPITABLE WATER VALUES AT OR BELOW 1.5
INCHES ON THURSDAY...WHICH IS AT OR BELOW NORMAL FOR THIS TIME OF
YEAR AND COULD RESULT IN A LARGELY DRY DAY. PRECIPITABLE WATER
VALUES GRADUALLY CLIMB FRIDAY THROUGH THE WEEKEND ON THE GFS. NOT
BEING A FAN OF REMOVING SMALL CHANCES OF PRECIPITATION ESPECIALLY IN
THE HUMIDITY OF SUMMER...WILL CONTINUE THE OVERALL TREND AT THE END
OF THE WEEK OF ISOLATED CHANCES FOR A SHOWER OR THUNDERSTORM IN MOST
AREAS EXCEPT CHANCES TOWARD THE COASTAL PLAIN CLOSER TO ANY SEA
BREEZE AND WHERE MOISTURE WILL BE SOMEWHAT GREATER. DURING THE
WEEKEND...AND ESPECIALLY BY SUNDAY...AS MOISTURE GRADUALLY INCREASES
AND DUE TO GROWING SYNOPTIC SCALE UNCERTAINTY...WILL FORECAST BROAD
CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS CENTRAL NORTH CAROLINA.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
AS OF 720 AM MONDAY...
FOG IS CONFINED TO THE NORTHERN COASTAL PLAIN THIS MORNING...AND
KRWI IS THE ONLY TAF SITE IMPACTED. THE FOG WILL LIFT BY
14Z...WITH VFR CONDITIONS TO PREVAIL TODAY. SCATTERED SHOWERS AND
STORMS ARE EXPECTED TO DEVELOP LATE THIS MORNING INTO THE
AFTERNOON HOURS...FIRST OVER THE COASTAL PLAIN...THEN SPREADING
WESTWARD TOWARD THE WESTERN PIEDMONT. THE SCATTERED NATURE OF THE
SHOWERS/STORMS PRECLUDE ANY MENTION OF ADVERSE CONDITIONS IN THE
TAF AT THIS TIME.
TONIGHT...
GUIDANCE SUGGESTS VSBYS WILL DROP OVER THE COASTAL PLAIN AGAIN
LATE TONIGHT...AND SOME PATCHY STRATUS IS POSSIBLE AS A LIGHT
NORTHEASTERLY WIND DEVELOPS BEHIND A WEAK SURFACE LOW FORECAST TO
MOVE UP THE COAST OVERNIGHT.
OUTLOOK...
SCATTERED THUNDERSTORMS ARE EXPECTED TUESDAY AND WEDNESDAY
AFTERNOON AS UPPER LEVEL DISTURBANCES CONTINUE TO MOVE ACROSS THE
REGION FROM THE NORTHWEST. BEYOND WEDNESDAY...TYPICAL SUMMERTIME
ISOLATED TO WIDELY SCATTERED STORMS ARE POSSIBLE EACH
AFTERNOON/EVENING...WITH EARLY MORNING FOG AND STRATUS ALSO
POSSIBLE.
&&
.CLIMATE...
THROUGH JULY 29...THE AVERAGE MONTHLY TEMPERATURE AT KRDU IS 83.8
DEGREES. THE WARMEST JULY ON RECORD IS 83.7 DEGREES...SET JUST
LAST YEAR. CONSIDERING EXPECTED HIGHS AND LOWS OVER THE NEXT
COUPLE OF DAYS...THIS JULY SHOULD EITHER BE THE WARMEST OR JUST
SHY OF THE WARMEST JULY ON RECORD.
AT KGSO...THE AVERAGE MONTHLY TEMPERATURE THROUGH JULY 29 IS 81.5
DEGREES. THIS IS CURRENTLY THIRD WARMEST...A HALF DEGREE WARMER THAN
THE 81.0 AVERAGE TEMPERATURE OF 2011...BUT WELL BELOW THE 82.6
RECORD OF 1893. CONSIDERING EXPECTED HIGHS AND LOWS OVER THE NEXT
COUPLE OF DAYS...IT APPEARS LIKELY THAT THE AVERAGE JULY TEMPERATURE
WILL RANK IN THE TOP THREE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...SMITH
SHORT TERM...SMITH
LONG TERM...DJF
AVIATION...SMITH
CLIMATE...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
316 AM EDT MON JUL 30 2012
.SYNOPSIS...
A STATIONARY FRONT OVER EASTERN NORTH CAROLINA WILL WEAKEN TODAY. A
SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE SOUTHEAST THROUGH THE
REGION THROUGH WEDNESDAY. UPPER LEVEL HIGH PRESSURE BUILDS OVER THE
REGION FROM THE WEST LATER IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 AM MONDAY...
TODAY...
WATER VAPOR IMAGERY THIS MORNING CONTINUES TO SHOW CONVECTIVELY
ENHANCED UPPER LEVEL DISTURBANCES MOVING SOUTHEAST OUT OF THE
UPPER MIDWEST...BETWEEN AN UPPER RIDGE OVER THE INNER MOUNTAIN
WEST AND A BROAD TROUGH OVER THE EASTERN US. THE MOST NOTABLE
DISTURBANCE APPROACHING THE CAROLINAS IN THE SHORT TERM IS
CURRENTLY NEAR THE IN/KY BORDER. THIS DISTURBANCE IS FORECAST TO
DEEPEN THE UPPER TROUGH AS IT SWINGS ACROSS NORTHERN GA AND SC
LATER TODAY. MODELS INDICATE THE LOW LEVEL WINDS WILL BACK IN
RESPONSE TO THE DEEPENING TROUGH...LEADING TO WEAK WARM
ADVECTION/VEERING PROFILE AND CONVECTIVE INITIATION ALONG A
STALLED OUT THE COLD FRONT OVER THE COASTAL PLAIN. WITH DEWPOINTS
HAVING RECOVERED INTO THE LOWER 70S AND PW UP TO 2 INCHES EAST OF
THE BOUNDARY BUT WEAK MID LEVEL LAPSE RATES...A MODEL CONSENSUS
GIVES 1000 TO MAYBE 1500 J/KG OF MLCAPE OVER THE COASTAL PLAIN AND
LESS TO THE WEST. THE WEAK CINH ON THE 00Z KMHX RAOB SHOULD ERODE
QUICKLY WITH HEATING LATER THIS MORNING AND HRRR SHOWS ISOLATED
CONVECTION AS EARLY AS 15-16Z AROUND SAMPSON/WAYNE COUNTY. WE WILL
SHOW POPS INCREASING WESTWARD DURING THE AFTERNOON AS THE
SOUTHEASTERLY FLOW AND ANY OUTFLOW OF SHOWERS/STORMS WILL HELP
SHIFT THE REMNANTS OF THE FRONT AND LOW LEVEL FOCUS WESTWARD.
HOWEVER...BASED ON THE 00Z KGSO RAOB AND FORECAST
SOUNDINGS...SHOWERS AND STORMS WILL ENCOUNTER A MORE PRONOUNCED
MID LEVEL CAP OVER THE WESTERN PIEDMONT..SO WE WILL KEEP POPS AT
SLIGHT CHANCE OVER MUCH OF THE WESTERN CWA. DEEP LAYER FLOW WILL
BE WEAK TODAY..SO ANY HAZARDOUS WEATHER WILL BE FROM PULSING
STRONGER STORMS AND AN ISOLATED PRECIP LOADED DOWNBURST.
GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH HIGHS RIGHT AT
NORMAL VALUES...88-90
TONIGHT...
MODELS SHOW A WEAK SURFACE WAVE DEVELOPING OVER THE COASTAL PLAIN
BENEATH WEAK HEIGHT FALLS ALOFT. A RELATIVELY STRONG 35KT 850MB JET
IS FORECAST TO DEVELOP OFFSHORE...WHICH IS WHERE MOST OF THE
OVERNIGHT SHOWERS AND STORMS WILL BE FOCUSED. THUS...THERE SHOULD BE
LITTLE IMPACTS ON SENSIBLE WEATHER FOR CENTRAL NC..OTHER THAN A
LIGHT NORTHEASTERLY WIND AND POSSIBLY SOME PATCHY STRATUS BY TUESDAY
MORNING. LOWS IN THE LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 310 AM MONDAY...
THE TRAIN OF UPPER LEVEL DISTURBANCES FROM THE UPPER MIDWEST TO THE
SOUTHERN APPALACHIANS WILL CONTINUE ON TUESDAY...AS MODELS SHOW A
80KT SPEED MAX AND ASSOCIATED VORTICITY DIVING TOWARD WESTERN NC AND
UP STATE SC BY EARLY AFTERNOON. MODELS INDICATE SOME CONVECTION OVER THE
MOUNTAINS AND ALONG THE COAST BY LATE MORNING...BUT A SHARPENING OF
THE MID/UPPER LEVEL TROUGH AXIS ASSOCIATED WITH THE AFOREMENTIONED UPPER
DISTURBANCE SHOULD LEAD TO SCATTERED SHOWERS AND STORMS OVER THE
WEST BY EARLY AFTERNOON. THE SEVERE THREAT OVER CENTRAL NC IS
SOMEWHAT UNCERTAIN AS THE STRONGER EFFECTIVE DEEP LAYER SHEAR WILL
LIKELY LIE TO THE SOUTHWEST OF THE CWA IN CLOSER PROXIMITY TO THE
BELT OF STRONGER MID LEVEL FLOW AND A FAIRLY STRONG SURFACE REFLECTION.
HOWEVER...IF STORMS CAN GET GOING OVER THE WESTERN AND SOUTHERN
PIEDMONT...THEN THERE WOULD BE A LOWER END THREAT OF DAMAGING WIND
GUSTS WITH STRONGER STORMS AND/OR MERGING COLD POOLS. WE WILL SHOW
HIGHEST POPS SHIFTING FROM THE SOUTHWEST TO EASTERN AREAS DURING THE
AFTERNOON AND EVENING...TRENDING DOWN TO A SLIGHT CHANCE OVERNIGHT.
WITH WEAK FLOW OVER CENTRAL NC DURING THE DAY AND NEAR MAXIMUM
INSOLATION...HIGHS SHOULD TOP OUT IN THE 86-90 RANGE BASED ON A
FORECAST 12Z LOW LEVEL THICKNESS OF 1405M. LOWS TUESDAY NIGHT ONCE
AGAIN IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
WEDNESDAY AND WEDNESDAY NIGHT...A MID-LEVEL TROUGH REMAINS OVER
CENTRAL NORTH CAROLINA...AND BOTH THE GFS AND THE NAM FORECAST AN
850MB TROUGH MOVING GRADUALLY WEST TO EAST ACROSS CENTRAL NORTH
CAROLINA THROUGH THE EVENING. THE NAM IS FARTHER SOUTH IN THE TRACK
OF THE 850MB WAVE AS COMPARED TO THE GFS...THOUGH BOTH FORECAST A
WEAK SURFACE WAVE MOVING OVER OR NEAR THE SANDHILLS AND THE SOUTHERN
COASTAL PLAIN AND TOWARD THE COAST WEDNESDAY AFTERNOON THROUGH
WEDNESDAY NIGHT. WITH 850MB THETA-E RIDGING FORECAST BY THE GFS
DURING THE DAY...AND THE APPROACH OF A WEAK 50KT JETLET AT 250MB
FROM THE NORTHWEST AIDING IN UPPER DIFFLUENCE...EXPECT AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING OVER MUCH OF CENTRAL
NORTH CAROLINA DURING THE DAY. THE GREATER CHANCES WILL BE TOWARD
INTERSTATE 95...IN VICINITY OF DEEPER MOISTURE WHERE PRECIPITABLE
WATER VALUES WILL BE AROUND 1.75 INCHES...AS COMPARED TO 1.5 INCHES
TOWARD THE YADKIN RIVER. IT SHOULD BE NOTED THAT THE GFS BUFR
SOUNDINGS ARE STABLE IN COMPARISON TO THE NAM BUFR SOUNDINGS...
DESPITE THE FACT THE GFS HAS THE 850MB TROUGH FARTHER NORTH AND ITS
QPF IS GREATER THAN THE NAM. 0-6KM SHEAR IS AROUND 25KT...NOT TOO
BAD COMPARED TO MANY RECENT DAYS...AND MLCAPE IS FORECAST AROUND
2000J/KG DURING WEDNESDAY AFTERNOON. ALTHOUGH A SURFACE WAVE IS
FORECAST TO MOVE OVER OR VERY CLOSE TO THE AREA...ESPECIALLY TO THE
SOUTHEAST...0-3KM HELICITY VALUES ARE FAIRLY SMALL OVER CENTRAL
NORTH CAROLINA...ONLY RISING TO NEAR 100M2/S2 TOWARD AND OFFSHORE OF
THE CAROLINA COAST. IF ANY ISOLATED SEVERE STORMS WOULD DEVELOP...
CURRENT THOUGHTS ARE THE BETTER CHANCE WOULD BE FROM ABOUT U.S. 1
EASTWARD.
BEHIND THE SURFACE AND 850MB WAVES...THE OVERALL AIR MASS DRIES ON
BUFR SOUNDINGS OVERNIGHT WEDNESDAY. HOWEVER...BUFR SOUNDINGS FROM
BOTH THE NAM AND THE GFS SHOW SLIGHT LAYER COOLING ABOVE 700MB...
AND THE GFS FORECASTS FAIRLY ROBUST POTENTIAL VORTICITY ON THE 1.5
PVU SURFACE MOVING INTO CENTRAL NORTH CAROLINA LATE AT NIGHT IN THE
NORTHWEST FLOW ALOFT. POSSIBLY FOR THESE REASONS BOTH THE NAM AND
GFS FORECAST LIGHT QPF OVER THE PIEDMONT OVERNIGHT...AND WILL
MAINTAIN A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM DUE TO THE
SLIGHT POTENTIAL FOR WHAT SHOULD BE ELEVATED...DEEP CONVECTION.
FOLLOWED A BLEND OF THE MET AND MAV MOS AND THE BIAS CORRECTED MOS
GUIDANCE FOR WEDNESDAY WITH HIGHS AROUND 90...AND EXPECT OVERNIGHT
LOWS WEDNESDAY AROUND 70.
FROM THURSDAY THROUGH THE END OF THE WEEK...LONG-TERM GUIDANCE
CONSENSUS IS FOR HEIGHTS TO INCREASE OVER AND AROUND CENTRAL NORTH
CAROLINA...AS RIDGING BUILDS EAST FROM THE PLAINS AND...PROBABLY
MORE SO...INFLUENCED BY RIDGING OVER THE NORTH ATLANTIC. DESPITE THE
RIDGING ALOFT...RELATIVE TROUGHINESS SHOULD REMAIN IN THE FLOW ALOFT
OVER THE MID-ATLANTIC. THE RESULT SHOULD BE LIGHT...BUT BROADLY
DIFFLUENT FLOW ALOFT. 1000-850MB THICKNESSES SHOULD WARM...LEADING
TO HIGHS MOST DAYS IN THE LOWER TO MID 90S...AND A FEW UPPER 90S
CANNOT BE COMPLETELY RULED OUT ESPECIALLY OVER THE SOUTHWEST
PIEDMONT...SANDHILLS...AND U.S. 1 CORRIDOR. CURRENTLY FORECAST DEW
POINTS LEAD TO HEAT INDICES AT THE END OF THE WEEK BETWEEN 100 AND
105 DEGREES...HIGHEST SATURDAY AND SUNDAY.
ALL OF THE LONG-TERM GUIDANCE SUGGESTS PERIODIC PASSAGE OF WEAK
MID-LEVEL DISTURBANCES IN THE BROADLY DIFFLUENT WEST-NORTHWEST FLOW
ALOFT. THE TIMING OF THESE...AND HOW THEY ARE INFLUENCED BY DEEP
CONVECTION UPSTREAM...IS DIFFICULT TO FORECAST IN THE LONG TERM. THE
COMBINATION OF SEA BREEZE AND PIEDMONT TROUGH INFLUENCES FOR
LOW-LEVEL LIFT...AND MID-LEVEL SHORTWAVES IN A MODESTLY MOIST AND
UNSTABLE AIR MASS...SHOULD RESULT IN ISOLATED TO SCATTERED CHANCES
FOR SHOWERS AND THUNDERSTORMS...GENERALLY DIURNALLY...EACH DAY. THE
LATEST GFS FORECASTS PRECIPITABLE WATER VALUES AT OR BELOW 1.5
INCHES ON THURSDAY...WHICH IS AT OR BELOW NORMAL FOR THIS TIME OF
YEAR AND COULD RESULT IN A LARGELY DRY DAY. PRECIPITABLE WATER
VALUES GRADUALLY CLIMB FRIDAY THROUGH THE WEEKEND ON THE GFS. NOT
BEING A FAN OF REMOVING SMALL CHANCES OF PRECIPITATION ESPECIALLY IN
THE HUMIDITY OF SUMMER...WILL CONTINUE THE OVERALL TREND AT THE END
OF THE WEEK OF ISOLATED CHANCES FOR A SHOWER OR THUNDERSTORM IN MOST
AREAS EXCEPT CHANCES TOWARD THE COASTAL PLAIN CLOSER TO ANY SEA
BREEZE AND WHERE MOISTURE WILL BE SOMEWHAT GREATER. DURING THE
WEEKEND...AND ESPECIALLY BY SUNDAY...AS MOISTURE GRADUALLY INCREASES
AND DUE TO GROWING SYNOPTIC SCALE UNCERTAINTY...WILL FORECAST BROAD
CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS CENTRAL NORTH CAROLINA.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
AS OF 150 AM MONDAY...
ANY FOG THIS MORNING SHOULD BE PATCHY AND MAINLY CONFINED TO THE
EASTERN PIEDMONT AND COASTAL PLAIN. CONFIDENCE IS ONLY HIGH ENOUGH
TO CARRY A PERIOD OF MVFR VSBY AT KRDU/KFAY/KRWI...WITH A SHORTER
PERIOD OF MORE DENSE FOG POSSIBLE AT KRWI BY 12Z.
THUNDERSTORMS WILL BE POSSIBLY BY EARLY AFTERNOON FROM KRDU TO THE
SOUTH AND EAST..POSSIBLY SPREADING WEST TOWARD THE TRIAD LATER IN
THE AFTERNOON/EVENING. HOWEVER..COVERAGE SHOULD BE TOO LOW FOR
MENTION AT ANY TAF SITE AT THIS TIME.
OUTLOOK...
STORMS ARE EXPECTED TO BE MORE NUMEROUS ON TUESDAY AS AN UPPER
LEVEL TROUGH CROSSES THE AREA. A TYPICAL THREAT OF SUMMERTIME
AFTERNOON AND EVENING THUNDERSTORMS AND EARLY MORNING FOG AND
STRATUS WILL THEN CONTINUE THROUGH THE REMAINDER OF THE WEEK..
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...SMITH
SHORT TERM...SMITH
LONG TERM...DJF
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1133 PM CDT SUN JUL 29 2012
.DISCUSSION...LATEST WATER VAPOR IMAGERY SHOWS A WESTERLY FLOW
INTO NORTH DAKOTA WITH A SHORTWAVE SEEN OVER FAR SOUTH CENTRAL
MONTANA. WEAK ECHOES BEING SUPPORTED WITH THIS PER REGIONAL RADAR.
THE HRRR DOES HOLD TOGETHER SOME OF THE PRECIPITATION AS IT SHIFTS
EAST OVERNIGHT WITH THE ADVANCING SHORTWAVE. WILL MENTION ISOLATED
THUNDERSTORMS FAR SOUTHWEST TO RIGHT ALONG THE SOUTHERN BORDER
OVERNIGHT AS THERE HAS BEEN SHOWERS DEVELOPING OVER SIOUX AND
EMMONS COUNTIES LAST COUPLE OF HOURS. THESE SHOWERS HAVE BEEN
ADVANCING SOUTHEAST INTO SOUTH DAKOTA. THE HRRR PICKS UP ON THIS
AND THUS WILL MAINTAIN THE ISOLATED THUNDERSTORMS OVERNIGHT FAR
SOUTHEAST. WITH CLEAR SKIES IN THE NORTH...TEMPERATURES COOLING A BIT
QUICKER AND HAVE ADJUSTED OVERNIGHT LOWS WITH WIDESPREAD MID/UPPER
50S. MONDAY STILL LOOKS VERY WARM AND DRY PER 00Z DATA. REST OF
FORECAST REMAINS ON TRACK.
&&
.AVIATION...HIGH PRESSURE WAS BUILDING INTO THE STATE FROM
MONTANA AND SASKATCHEWAN. A TROUGH AND COLD FRONTAL BOUNDARY
ACROSS SOUTHEAST NORTH DAKOTA THROUGH NORTH CENTRAL SOUTH DAKOTA
WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS ACROSS FAR
SOUTHERN AND EASTERN NORTH DAKOTA SUNDAY NIGHT. ALL TAF SITES WILL
BE VFR THROUGH THE TAF PERIOD AND THUNDERSTORMS WILL REMAIN SOUTH
OF ALL AERODROMES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1041 PM EDT TUE JUL 31 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCE THIS AFTERNOON INTO TONIGHT. COLD FRONT
MOVES THROUGH WEDNESDAY. HIGH PRESSURE WEDNESDAY NIGHT THROUGH
FRIDAY. COLD FRONT ARRIVES LATER SUNDAY AND SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
1030 PM UPDATE...SHOWERS/STORMS WINDING DOWN ACROSS THE FORECAST
AREA AS LACK OF REGENERATION ALLOWED ONGOING CONVECTION TO FINALLY
BEGIN MOVING OFF TO THE EAST. CURRENT SHOWERS OVER FAR EASTERN HIGH
TERRAIN WILL END OVER THE NEXT HOUR OR TWO. THOUGH MOST LOCATIONS
WILL REMAIN DRY...WILL CONTINUE A SLIGHT CHANCE OF RAIN SHOWERS
OVERNIGHT FOR MUCH OF THE AREA WITH BOTH THE RUC AND NAM DEPICTING
ANOTHER VORT MAX PUSHING SE-WARD ACROSS OHIO...WITH SOME LLVL
MOISTURE IN PLACE ALONG WITH EXISTING MESOSCALE OUTFLOW BOUNDARIES
FROM THIS EVENING/S STORMS.
PREVIOUS DISCUSSION...
NUMEROUS SHOWERS AND THUNDERSTORMS CURRENTLY DEPICTED BY RADAR
OVER NORTHERN WV MOUNTAINS...WITH MORE ISOLATED ACTIVITY SOUTHWARD
OVER THE MOUNTAINS. RAP SHOWS A VORT MAX ASSOCIATED WITH THIS
ACTIVITY...WHICH PUSHES OFF TO THE EAST THROUGH THE
AFTERNOON...WITH A SECOND VORT MAX MOVING IN FROM THE WEST. STILL
WAITING FOR SIGNS OF THE SECOND WAVE TO SHOW...AS AN OUTFLOW
BOUNDARY FROM EARLIER CONVECTION IN NORTHERN INDIANA ALSO MOVES
IN. VISIBLE SAT SHOWED SOME BUILDING CUMULUS CLOUDS IN PERRY
COUNTY...UP TOWARDS PBZ...ALONG THIS BOUNDARY BUT IT HAS BEEN
FAIRLY SLOW TO CONTINUE DEVELOPMENT. EXPECTING MORE DEVELOPMENT AS
THIS BOUNDARY PUSHES INTO CWA...WHERE THERE HAS BEEN A GOOD AMOUNT
OF HEATING SO FAR TODAY. INTERESTINGLY...THE WRFNMM SHOWS AN
OUTFLOW BOUNDARY COMING WEST OUT OF THE ACTIVITY NEAR
EKN...MEETING THE BOUNDARY APPROACHING FROM THE
NORTHEAST...DEVELOPING PRETTY ROBUST CONVECTION ALONG I-79. WILL
HAVE TO WAIT AND SEE JUST HOW THIS GOES...BUT AT ANY RATE...EXPECT
ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON. ISOLATED
SHOWERS AND STORMS MAY LINGER OVERNIGHT...WITH SCATTERED STORMS
AGAIN WEDNESDAY AS ANOTHER UPPER LEVEL SHORTWAVE TROUGH PASSES
THROUGH.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
MODELS SHOW A BRIEF LULL IN THE ACTIVE THUNDERSTORM PATTERN AS AN
UPPER LEVEL DISTURBANCE IN NORTHWEST FLOW ALOFT EXITS TO THE
SOUTHEAST AND ALLOWS WEAK HIGH PRESSURE TO BUILD IN FOR WEDNESDAY
NIGHT AND THURSDAY. THIS WILL ALLOW DRIER AIR TO OVERSPREAD THE
AREA...THOUGH TEMPERATURES THURSDAY WILL BE SIMILAR TO WEDNESDAY.
HOWEVER...WITH THE DRIER AIR...WEDNESDAY NIGHT WILL BE SOMEWHAT
COOLER THAN PREVIOUS NIGHTS. LOOK FOR TEMPERATURES TO REACH AROUND
90 DEGREES MANY LOW LAND LOCATIONS AGAIN THURSDAY...BUT LESS
HUMIDITY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HEIGHTS ONCE AGAIN BUILD IN FROM THE WEST BY FRIDAY WITH THE BERMUDA
HIGH STRENGTHENING...ALLOWING THE HEAT AND HUMIDITY TO MOVE BACK IN
FROM THE SOUTHWEST. CHANCES FOR STORMS INCREASE LATER FRIDAY AND
SATURDAY ON MORE OF A DIURNAL BASIS WITH THE INCREASING INSTABILITY.
THIS WILL ALSO BRING MORE HEAT BACK...WITH HIGH TEMPERATURES FRIDAY
AND SATURDAY REACHING INTO THE 90S AGAIN.
ANOTHER STRONGER NORTHWEST FLOW SYSTEM AND ATTENDING COLD FRONT DROP
SOUTHEASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THIS WILL
INCREASE CHANCES FOR STORMS SUNDAY AND SUNDAY NIGHT AHEAD OF THE
FRONT. MODELS ARE SOMEWHAT DIFFERENT IN TIMING OF THE SYSTEM...BUT
SUING THE SLOWER EURO AND GFS MODELS IN THIS HIGH SUMMER PATTERN LOOKS
REASONABLE. THIS WILL PUSH THE FRONT THROUGH MONDAY MORNING WITH
SHOWERS DECREASING FROM NORTHWEST TO SOUTHEAST ON MONDAY...FOLLOWED
BY SLIGHTLY COOLER TEMPS.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
CONVECTION CONTINUING ACROSS ROUGHLY THE EASTERN THIRD OF THE
FORECAST AREA. SHOULD SEE THIS ACTIVITY LARGELY DISSIPATE BTWN
03Z-06Z. HEAVY RAINS AND STRONG WINDS WILL BE POSSIBLE AT EASTERN
SITES OVER THE NEXT HOUR OR TWO.
LIGHT AND VARIABLE WINDS WITH SCATTERING CLOUDS WILL RESULT IN
FOG/REDUCED VISBYS...PARTICULARLY AT EKN WHERE RAINFALL HAS BEEN
RECEIVED THIS EVENING. WILL NEED TO WATCH TO SEE IF ANY OTHER
SITES RECEIVE PRECIP THIS EVENING. WILL AGAIN SEE SCATTERED
SHOWERS AND THUNDERSTORMS ON WEDNESDAY...ESPECIALLY FROM CRW-CKB
AND WESTWARD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF THUNDERSTORMS COULD VARY THROUGH THE
PERIOD. TIMING AND DENSITY OF FOG MAY VARY OVERNIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 08/01/12
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H H H H M M M H
HTS CONSISTENCY H H H H H H H H H M M H
BKW CONSISTENCY H H H H H H H H H L L H
EKN CONSISTENCY H H H L L L L L L L L M
PKB CONSISTENCY H H H H M H H H H M M H
CKB CONSISTENCY H H H H H H H H H L L H
AFTER 00Z THURSDAY...
BRIEF IFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY
AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/MZ
NEAR TERM...MZ/50
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...50
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
745 PM EDT TUE JUL 31 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCE THIS AFTERNOON INTO TONIGHT. COLD FRONT
MOVES THROUGH WEDNESDAY. HIGH PRESSURE WEDNESDAY NIGHT THROUGH
FRIDAY. COLD FRONT ARRIVES LATER SUNDAY AND SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
600 PM UPDATE...RAMPED UP POPS ACROSS EASTERN HIGH TERRAIN AND
POINTS NORTHWEST OF THERE...ROUGHLY ALONG AND EAST OF INTERSTATE
79. MUCH LIKE LAST EVENING...PROPAGATION OF STORMS BEING DRIVEN BY
OUTFLOW/COLD POOL INTERACTION WHICH HAS BEEN PUSHING NW OUT OF THE
HIGHER TERRAIN TOWARDS THE I-79 CORRIDOR. ALSO LOWERED POPS A BIT
ACROSS SE OHIO ZONES. EXPECT THE STRONGEST STORMS TO BEGIN WINDING
DOWN OVER THE NEXT HOUR OR TWO.
PREVIOUS DISCUSSION...
NUMEROUS SHOWERS AND THUNDERSTORMS CURRENTLY DEPICTED BY RADAR
OVER NORTHERN WV MOUNTAINS...WITH MORE ISOLATED ACTIVITY SOUTHWARD
OVER THE MOUNTAINS. RAP SHOWS A VORT MAX ASSOCIATED WITH THIS
ACTIVITY...WHICH PUSHES OFF TO THE EAST THROUGH THE
AFTERNOON...WITH A SECOND VORT MAX MOVING IN FROM THE WEST. STILL
WAITING FOR SIGNS OF THE SECOND WAVE TO SHOW...AS AN OUTFLOW
BOUNDARY FROM EARLIER CONVECTION IN NORTHERN INDIANA ALSO MOVES
IN. VISIBLE SAT SHOWED SOME BUILDING CUMULUS CLOUDS IN PERRY
COUNTY...UP TOWARDS PBZ...ALONG THIS BOUNDARY BUT IT HAS BEEN
FAIRLY SLOW TO CONTINUE DEVELOPMENT. EXPECTING MORE DEVELOPMENT AS
THIS BOUNDARY PUSHES INTO CWA...WHERE THERE HAS BEEN A GOOD AMOUNT
OF HEATING SO FAR TODAY. INTERESTINGLY...THE WRFNMM SHOWS AN
OUTFLOW BOUNDARY COMING WEST OUT OF THE ACTIVITY NEAR
EKN...MEETING THE BOUNDARY APPROACHING FROM THE
NORTHEAST...DEVELOPING PRETTY ROBUST CONVECTION ALONG I-79. WILL
HAVE TO WAIT AND SEE JUST HOW THIS GOES...BUT AT ANY RATE...EXPECT
ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON. ISOLATED
SHOWERS AND STORMS MAY LINGER OVERNIGHT...WITH SCATTERED STORMS
AGAIN WEDNESDAY AS ANOTHER UPPER LEVEL SHORTWAVE TROUGH PASSES
THROUGH.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
MODELS SHOW A BRIEF LULL IN THE ACTIVE THUNDERSTORM PATTERN AS AN
UPPER LEVEL DISTURBANCE IN NORTHWEST FLOW ALOFT EXITS TO THE
SOUTHEAST AND ALLOWS WEAK HIGH PRESSURE TO BUILD IN FOR WEDNESDAY
NIGHT AND THURSDAY. THIS WILL ALLOW DRIER AIR TO OVERSPREAD THE
AREA...THOUGH TEMPERATURES THURSDAY WILL BE SIMILAR TO WEDNESDAY.
HOWEVER...WITH THE DRIER AIR...WEDNESDAY NIGHT WILL BE SOMEWHAT
COOLER THAN PREVIOUS NIGHTS. LOOK FOR TEMPERATURES TO REACH AROUND
90 DEGREES MANY LOW LAND LOCATIONS AGAIN THURSDAY...BUT LESS
HUMIDITY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HEIGHTS ONCE AGAIN BUILD IN FROM THE WEST BY FRIDAY WITH THE BERMUDA
HIGH STRENGTHENING...ALLOWING THE HEAT AND HUMIDITY TO MOVE BACK IN
FROM THE SOUTHWEST. CHANCES FOR STORMS INCREASE LATER FRIDAY AND
SATURDAY ON MORE OF A DIURNAL BASIS WITH THE INCREASING INSTABILITY.
THIS WILL ALSO BRING MORE HEAT BACK...WITH HIGH TEMPERATURES FRIDAY
AND SATURDAY REACHING INTO THE 90S AGAIN.
ANOTHER STRONGER NORTHWEST FLOW SYSTEM AND ATTENDING COLD FRONT DROP
SOUTHEASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THIS WILL
INCREASE CHANCES FOR STORMS SUNDAY AND SUNDAY NIGHT AHEAD OF THE
FRONT. MODELS ARE SOMEWHAT DIFFERENT IN TIMING OF THE SYSTEM...BUT
SUING THE SLOWER EURO AND GFS MODELS IN THIS HIGH SUMMER PATTERN LOOKS
REASONABLE. THIS WILL PUSH THE FRONT THROUGH MONDAY MORNING WITH
SHOWERS DECREASING FROM NORTHWEST TO SOUTHEAST ON MONDAY...FOLLOWED
BY SLIGHTLY COOLER TEMPS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
CONVECTION CONTINUING ACROSS ROUGHLY THE EASTERN THIRD OF THE
FORECAST AREA. SHOULD SEE THIS ACTIVITY LARGELY DISSIPATE BTWN
03Z-06Z. HEAVY RAINS AND STRONG WINDS WILL BE POSSIBLE AT EASTERN
SITES OVER THE NEXT HOUR OR TWO.
LIGHT AND VARIABLE WINDS WITH SCATTERING CLOUDS WILL RESULT IN
FOG/REDUCED VISBYS...PARTICULARLY AT EKN WHERE RAINFALL HAS BEEN
RECEIVED THIS EVENING. WILL NEED TO WATCH TO SEE IF ANY OTHER
SITES RECEIVE PRECIP THIS EVENING. WILL AGAIN SEE SCATTERED
SHOWERS AND THUNDERSTORMS ON WEDNESDAY...ESPECIALLY FROM CRW-CKB
AND WESTWARD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF THUNDERSTORMS COULD VARY THROUGH THE
PERIOD. TIMING AND DENSITY OF FOG MAY VARY OVERNIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 08/01/12
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H H H H M M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY H H H H H H H H H H H L
EKN CONSISTENCY H H H H H L L L L L L L
PKB CONSISTENCY H H H H H H M H H H H M
CKB CONSISTENCY H H H H H H H H H H H L
AFTER 00Z THURSDAY...
BRIEF IFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY
AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/MZ
NEAR TERM...MZ/50
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...50
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
126 AM EDT MON JUL 30 2012
.SYNOPSIS...
A CHANCE FOR SCATTERED SHOWERS AND THUNDERSTORMS BEGINS ON MONDAY
AS AN UPPER DISTURBANCE WILL DROP SOUTHEAST ACROSS THE AREA. A
WEAK COLD FRONT WILL THEN PUSH THROUGH THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SURFACE HIGH PRESSURE REMAINS IN PLACE OVER THE SOUTHERN GREAT
LAKES AND MIDDLE OHIO VALLEY REGIONS. NORTHWESTERLY FLOW ALOFT
WILL CONTINUE TO SPREAD IN A FEW MID AND HIGH CLOUDS...GRADUALLY
THICKENING SLIGHTLY GOING INTO TOMORROW. THE EARLIER ADJUSTMENTS
TO A DRY FORECAST STILL APPEAR TO BE THE BEST COURSE OF ACTION.
LOW TEMPS WERE ADJUSTED SLIGHTLY BASED PRIMARILY ON THE MET
NUMBERS (RECENT RAP RUNS LOOK WELL TOO WARM...GIVEN THAT IT IS
ALREADY IN THE UPPER 60S IN OUTLYING AREAS).
PREVIOUS DISCUSSION >
7PM UPDATE...MADE ONLY MINOR DEWPOINT AND CLOUD TWEAKS OVERNIGHT.
PREVIOUS DISCUSSION...EARLIER MODEL RUNS WERE PUSHING A WET SOLUTION
IN HANDLING APPROACHING WEAK S/WV PUSHING SSE ACROSS INDIANA
OVERNIGHT. UPDATED RUNS...INCLUDING THE HRRR/WRF/ECMWF
SOLUTIONS...THE DRY BOUNDARY LAYER AND NO STRONG FORCING MECHANISM
HAVE PROMPTED DECISION TO KEEP PRECIP OUT OF AREA AS A RESULT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
AS THE SHORT WAVE DROPS THROUGH AREA ON MONDAY...AGAIN SOME
DIFFERENCES IN PRECIP PLACEMENT AND COVERAGE. HAVE KEPT ONLY A 20
POP ACROSS THE AREA DUE TO DRIER BOUNDARY LAYER ONLY WEAK FORCING
AND DIMINISHED COVERAGE AS A RESULT. GFS HAD BEEN VERY AGGRESSIVE
WITH THE PRECIP...BUT IS AGAIN HANDLING SURFACE DEWPOINTS
POORLY...SO HAVE NOT CONSIDERED THIS SOLUTION. 00Z ECMWF RUN HAD
ALSO BEEN MORE AGGRESSIVE WITH PRECIP BUT 12Z RUN CAME IN MORE
CONSERVATIVE...GIVING FURTHER SUPPORT FOR SLIGHT CUTS IN PRECIP
CHANCES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HAVE TAKEN A BLEND OF NCEP/HPC AND THE 00Z ECMWF FOR THE EXTENDED
FORECAST AS THEY OFFER THE BEST SOLUTION AND HAVE CONTINUITY.
A WEAK COLD FRONT IS FORECAST TO SLIDE INTO THE REGION ON TUESDAY
AND WITH A S/WV DROPPING DOWN IN THE NORTHWEST FLOW ALOFT...IT
APPEARS THAT THERE WILL BE A CHANCE OF SHOWERS/STORMS TUESDAY INTO
TUESDAY EVENING. IT STILL LOOKS LIKE A SURFACE RIDGE WILL THEN BUILD
INTO THE REGION BY WEDNESDAY NIGHT AND PERSIST ACRS THE AREA INTO
THURSDAY. UPR LVL FLOW BRIEFLY TRANSITIONS MORE TO A ZONAL PATTERN
ON FRIDAY...AND WITH WEAK RETURN SFC FLOW AROUND DEPARTING HIGH AND
PERHAPS AN EMBEDDED DISTURBANCE RIPPLING ALOFT...HAVE KEPT A LOW
CHANCE FOR SHOWERS/STORMS. A STRONGER S/WV AND COLD FRONT IS POISED
TO AFFECT THE REGION SATURDAY INTO SATURDAY NIGHT...OFFERING AN
ENHANCED CHANCE OF SHOWERS AND STORMS. THE COLD FRONT IS PROGGED TO
SLIDE SE OF THE AREA ON SUNDAY...BRING AN END TO THE PCPN AND
ALLOWING DRIER AIR TO BUILD BACK INTO THE AREA ONCE AGAIN.
TEMPERATURES ON A WHOLE SHOULD AVERAGE ABOVE NORMAL THROUGH THE
PERIOD. HOW FAR ABOVE NORMAL WILL DEPEND ON CLOUD COVER AND
PRECIPITATION COVERAGE.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
MID AND HIGH CLOUDS WILL CONTINUE TO WORK INTO THE AREA DURING THE
OVERNIGHT HOURS AND INTO THE DAY ON MONDAY. THESE CLOUDS SHOULD
HELP TO LIMIT SOME FOG FORMATION HOWEVER HAVE ADDED MVFR FOG TO
KILN. IN ADDITION HAVE ADDED IFR FOG TO KLUK DUE TO LIGHT SE FLOW.
VFR CONDITIONS WILL RETURN TO THE TAF SITES BY 13Z ON MONDAY. A
WEAK SYSTEM WILL MOVE CLOSE TO THE AREA ON MONDAY HOWEVER CURRENT
INDICATIONS ARE THAT PRECIPITATION WILL STAY SW OF THE AREA TAF
SITES. AN ISOLATED SHOWER IS NOT OUT OF THE QUESTION HOWEVER
AROUND THE KCVG AND KLUK AREA FOR MONDAY. WINDS WILL BE LESS THAN
10 KNOTS THROUGH THE TAF PERIOD.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE ON TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...JDR/HATZOS
SHORT TERM...JDR
LONG TERM...HICKMAN
AVIATION...NOVAK
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1136 PM CDT SUN JUL 29 2012
.UPDATE...
UPDATED FOR AVIATION.
&&
.PREV DISCUSSION... /ISSUED 923 PM CDT SUN JUL 29 2012/
UPDATE...
THE FORECAST FOR TONIGHT STILL LOOKS LARGELY ON TRACK. A FEW
STORMS CONTINUE OVER SOUTHERN MISSOURI...BUT ARE IN A WEAKENING
PHASE. LITTLE RIPPLES CONTINUE TO SPILL DOWN THE FORWARD FLANK OF
AN EXPANSIVE RIDGE OVER THE SOUTHERN PLAINS WHICH MAY KICK OFF
ADDITIONAL STORMS OVERNIGHT...SIMILAR TO WHAT THE THE GLOBAL
MODELS AND THE HRRR ARE SHOWING OVERNIGHT. THUS...DESPITE LITTLE
ACTIVITY UPSTREAM AT THE PRESENT TIME...CANNOT RULE OUT ADDITIONAL
DEVELOPMENT BUT IT IS BEGINNING TO LOOK A LITTLE LESS LIKELY.
ANY ACTIVITY TONIGHT WILL HAVE SIGNIFICANT IMPLICATIONS ON
TEMPERATURES TOMORROW. 00Z NAM CONTINUES TO ADVERTISE 110+ DEGREE
HIGHS ACROSS THE DELTA MONDAY AS AN INCREDIBLE THERMAL RIDGE
ARRIVES WITH 925 MB TEMPS IN THE +32 TO +35C RANGE. THE NAM HAS
BEEN RATHER CONSISTENT IN SHOWING THIS FOR THE PAST FEW DAYS AND
IT SEEMED TO HAVE INITIALIZED WELL OVER THE PLAINS TONIGHT.
THUS...IT IS A LITTLE CONCERNING. HISTORY HAS SHOWN...HOWEVER...
THAT IT TENDS TO RUN ABOUT 5 DEGREES TOO WARM ON OTHER SUCH
EXTREME HEAT DAYS THIS MONTH. THE CANADIAN AND ECMWF ARE SHOWING
105 DEGREE HIGHS WEST OF THE RIVER AS WELL SO MODELS SEEM TO BE IN
A BIT OF AGREEMENT. TOUGH TO SAY WHAT DEW POINTS WILL DO...BUT AM
THINKING WITH A STRONG WESTERLY FLOW AND A DRY SLOT ASSOCIATED
WITH LOW PRESSURE OVER SOUTHEAST MISSOURI PUNCHING IN...WE SHOULD
BE ABLE TO MIX DOWN INTO THE 60S AT LEAST IN THE DELTA. THIS WILL
YIELD RH VALUES IN THE 20S WITH FIRE WEATHER BECOMING A CONCERN.
MIXING SHOULD ALSO KEEP HEAT INDEX VALUES BELOW 110...BUT IT WILL
BE CLOSE.
BORGHOFF
PREV DISCUSSION... /ISSUED 320 PM CDT SUN JUL 29 2012/
DISCUSSION...
SKIES ARE PARTLY CLOUDY ACROSS MUCH OF WEST TENNESSEE AND PARTS OF
NORTH MISSISSIPPI THIS AFTERNOON WITH MOSTLY SUNNY SKIES ACROSS
THE REMAINDER OF THE FORECAST AREA. TEMPERATURES RANGE FROM THE
MID 80S TO UPPER 90S. SOME SHOWERS AND THUNDERSTORMS CONTINUE TO
MOVE ACROSS SECTIONS OF WEST TENNESSEE THIS AFTERNOON. THIS
ACTIVITY IS ASSOCIATED WITH A UPPER LEVEL DISTURBANCE WHICH IS
MOVING ACROSS SOUTHEAST MISSOURI THIS AFTERNOON AND SHOULD MOVE
THROUGH MIDDLE TENNESSEE AND NORTH ALABAMA TONIGHT. SOME ADDITIONAL
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE TONIGHT MAINLY OVER
NORTHERN AND EASTERN SECTIONS OF THE FORECAST AREA.
BY MONDAY...UPPER LEVEL RIDGE WILL CONTINUE TO BUILD INTO THE
REGION BRINGING ANOTHER ROUND OF VERY HOT AND HUMID WEATHER. HEAT
INDEX VALUES WILL LIKELY EXCEED 105 DEGREES OVER ROUGHLY THE
WESTERN HALF OF THE FORECAST AREA SO WILL ISSUE A HEAT ADVISORY
FOR MONDAY. TEMPERATURES WILL BE QUITE HOT WITH AFTERNOON READINGS
RANGING FROM THE MID 90S TO AROUND 102. ISOLATED THUNDERSTORMS WILL
BE POSSIBLE BOTH MONDAY AND MONDAY NIGHT AS WELL AS ANOTHER WEAK
UPPER LEVEL DISTURBANCE MOVES THROUGH THE REGION MONDAY NIGHT.
TUESDAY WILL BE ANOTHER VERY HOT DAY WITH AFTERNOON TEMPERATURES
IN THE MID 90S TO AROUND 100. A FEW ISOLATED THUNDERSTORMS WILL BE
POSSIBLE MAINLY OVER EASTERN SECTIONS TUESDAY AND TUESDAY NIGHT.
BY WEDNESDAY...THE UPPER LEVEL RIDGE WILL RETREAT SOME TO THE WEST
AND REMAIN OVER THE SOUTHWEST U.S. FOR MUCH OF THE REMAINDER OF
THE FORECAST PERIOD. AS A RESULT...TEMPERATURES FROM WEDNESDAY
THROUGH NEXT SUNDAY WILL NOT BE AS HOT AS THEY WILL BE FOR MONDAY
AND TUESDAY WITH AFTERNOON READINGS MAINLY IN THE MID 90S.
ISOLATED THUNDERSTORMS WILL ALSO BE POSSIBLE THROUGH THE PERIOD AS
WELL.
ARS
&&
.AVIATION...
06Z TAFS
MIDLEVEL CLOUDS NEAR FL100 CONTINUED TO STREAM SOUTH THROUGH THE
MID MS RIVER VALLEY AT 0430Z. THESE CLOUDS AND ASSOCIATED SHRA
WERE ENHANCED BY AN UPPER LEVEL DISTURBANCE EVIDENT ON GOES WATER
VAPOR IMAGERY. SUFFICIENT ELEVATED INSTABILITY EXISTED FOR
ISOLATED TSRA IN THE SHORT TERM FOR THE MKL VICINITY. OVERNIGHT
TSRA CHANCES FOR MEM ARE NONZERO... BUT APPEAR MORE LIMITED THAN
FURTHER EAST AT MKL AND PERHAPS TUP.
PWB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 78 103 80 101 / 10 20 20 20
MKL 72 98 75 99 / 30 20 20 20
JBR 75 105 78 102 / 10 20 20 10
TUP 73 97 77 98 / 20 20 20 20
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY FROM 10 AM TO 8 PM CDT MONDAY FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY FROM 10 AM TO 8 PM CDT MONDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY FROM 10 AM TO 8 PM CDT MONDAY FOR CALHOUN-COAHOMA-
DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-TALLAHATCHIE-TATE-
TUNICA-YALOBUSHA.
TN...HEAT ADVISORY FROM 10 AM TO 8 PM CDT MONDAY FOR CROCKETT-DYER-
FAYETTE-GIBSON-HAYWOOD-LAKE-LAUDERDALE-OBION-SHELBY-TIPTON-
WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
109 PM EDT MON JUL 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL DRIFT EAST TO OFF THE MID ATLANTIC COAST THIS
EVENING. RETURN SOUTHEAST FLOW AROUND THE HIGH WILL BRING
INCREASING MOISTURE INTO TONIGHT. AN UPPER LEVEL TROUGH OF LOW
PRESSURE WILL THEN RESIDE OVER THE EASTERN UNITED
STATES...YIELDING THE POTENTIAL FOR UNSETTLED WEATHER INTO MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 925 AM EDT MONDAY...
ISOLATED SHOWERS CONTINUE TO LINGER ALONG THE EASTERN SLOPES AIDED
BY WEAK SE FLOW INTO THE BLUE RIDGE AND LOW LEVEL THETA-E GRADIENT
PARKED ALONG RIDGES. HOWEVER MORNING RAOBS SHOW THAT THE MOISTURE
REMAINS QUITE SHALLOW IN THE ZONE OF EASTERLY FLOW...CAPPED BY VERY
DRY AIR ALOFT WITH ONLY VERY WEAK MID LEVEL STEERING. THIS
SUPPORTS ADDED SLOW MOVING HEAVY RAIN PRODUCING SHRA/TSRA BUT
EXPECT COVERAGE TO BE LIMITED SOMEWHAT BY LACK OF MUCH SUPPORT
GIVEN PASSAGE OF ONE S/W ATTM AND ONLY FAINT ENERGY SPILLING IN
FROM THE WEST THIS AFTERNOON. LATEST FORECAST SOUNDINGS DO SHOW
THE CAP SLOWLY ERODING OVER THE WEST LATER ON WITH MOST LOCAL
MODELS AS WELL AS THE HRRR PRODUCING A SCATTERING OF CONVECTION
MAINLY MOUNTAINS. THUS BUMPED UP POPS SOME ACROSS THE WEST ESPCLY
BLUE RIDGE TO INIT AND INCLUDED A BRIEF HEAVY RAIN MENTION FOR
SLOW MOVING STORMS. ANY SVR SHOULD BE ISOLATED AND MAINLY WHERE
HELPED BY PRECIP LOADING PER HIGH WINDEX/DCAPE VALUES OFF MODIFIED
RAOBS. OTRW MAINLY PC WITH PLENTY OF CU AROUND AS MOISTURE SLOWLY
RETURNS. MORNING THICKNESS SUPPORTING HIGHS MOSTLY IN THE 80S BUT
MAYBE NOT QUITE AS WARM IN SPOTS SO TWEAKED DOWN RANGES A BIT.
PREVIOUS DISCUSSION AS OF 725 AM EDT MONDAY...
SHORTWAVE MOVING ACROSS ERN TN ATTM...WITH EASTERLY FLOW INTO THE
MTNS STILL KEEPING SHOWERS/FEW TSRA GOING FROM SOUTH OF ROANOKE TO
JUST SOUTH OF THE VA BORDER ALONG ROCKINGHAM/STOKES COUNTY LINE.
WILL SEE THE ACTIVITY CONTINUE UNTIL SHORTWAVE INFLUENCE
PASSES...ALTHOUGH WINDOW WILL BE SHORT AS ANOTHER SHORTWAVE HEADS
INTO THE COALFIELDS OF ERN KY BY 18Z TODAY. ADJUSTED POPS TO
ACCOUNT FOR THIS AND UPPED TEMPS THIS MORNING AS MORE CLOUD COVER
HAS KEPT TEMPS IN THE MID 60S TO AROUND 70.
PREVIOUS VALID DISCUSSION...
SHORTWAVE SINKS SOUTHEAST INTO GA/SC BY MIDDAY AND SHOULD TAKE
MOST OF THE HIGH CLOUDS WITH IT. ANOTHER WAVE PUSHES EAST OUT OF
THE OHIO VALLEY INTO THE BLUE RIDGE THIS AFTERNOON AND WITH UPPER
TROUGH OVERHEAD WITH UPPER DIVERGENCE AHEAD OF 80 KNOT
JET...SHOULD SEE ENOUGH LIFT TO INDUCE SCATTERED STORMS AFTER
MIDDAY. THE 00Z GFS/12Z ECMWF SEEM TO BE IN THE SAME CAMP IN
REGARDS TO THE UPPER LEVEL FEATURES AND TRY TO AIM THE BEST
COVERAGE OF SHOWERS AND STORMS FROM THE ALLEGHANY HIGHLANDS/WV
MTNS SOUTHEAST ALONG THE BLUE RIDGE. KEPT HIGHER POPS HERE WITH A
LESSER THREAT OVER THE PIEDMONT OF NC. WITH FLOW IN THE LOWEST
5KFT EAST TO SOUTHEAST AND WEST TO NW FLOW ALOFT SOME OF THESE
STORMS THAT FORM COULD BE ANCHORED TO THE RIDGES...RESULTING IN
POTENTIALLY HEAVIER RAIN AND POSSIBLE ISOLATED FLOODING...ALTHOUGH
PWATS ARE NOT AS HIGH AS A FEW DAYS AGO RANGING FROM 1 TO 1.4
INCHES.
TONIGHT...ONE SHORTWAVE EXITS WITH THE NEXT UPSTREAM WAVE MOVING
TOWARD THE TN VALLEY INTO THE SRN APPALACHIANS. GFS/ECMWF/SREF
LINGER THE CHANCES OF SHRA/TSRA ACROSS THE AREA THROUGH THE NIGHT
MAINLY ALONG EITHER SIDE OF THE BLUE RIDGE WHERE BEST CONVERGENCE
LIES. LOWERED POPS TO 30 AROUND THE BLUE RIDGE WITH SLIGHT CHANCE
EITHER SIDE.
FOR TEMPS...TODAY WILL SEE INCREASING HUMIDITY IN THE EAST PER SE
FLOW AND WITH CLOUDS FORMING FASTER...THINK MET MOS MAY HAVE BETTER
RESULTS WHICH IS A DEGREE OR THREE COOLER THAN MAV MOS. HIGHS WILL
RANGE FROM NEAR 90 EAST AND IN THE ROA/SRN SHENANDOAH VALLEYS TO
LOWER TO MID 80S WEST.
TONIGHT...THE FLOW IS WEAK AT THE SFC SO THINK LOWS SHOULD BE
SIMILAR TO THIS MORNING WITH 60S CWA WIDE...LOWER IN THE WEST.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 340 AM EDT SUNDAY...
WILL START OUT THE DAY TUESDAY WITH THE PERSISTENT UPPER LEVEL
TROUGH DRIFTING SLOWLY TO THE EAST...BUT STILL SITUATED ALMOST
DIRECTLY OVER OUR AREA. THE SUBTLE UPPER DISTURBANCES RIDING INTO
THE BASE OF THE TROUGH FROM THE MIDWEST WILL TRIGGER ANOTHER ROUND
OF SCATTERED THUNDERSTORM ACTIVITY...INITIALLY DEVELOPING OVER THE
MOUNTAINS WITH SUPPORT FROM CONVERGENCE ALONG THE RIDGELINES...BUT
THEN SPREADING INTO THE PIEDMONTS AS AFTERNOON HEATING MAXIMIZES. AS
HAS BEEN TYPICAL OVER THE PAST SEVERAL WEEKS...A FEW OF THESE STORMS
WILL BECOME SEVERE...LIKELY WITHIN MINUTES OF DEVELOPING...WITH
DAMAGING WINDS AS THE GREATEST THREAT. PERIODS OF HEAVY RAIN...WITH
2 TO 3 INCH AMOUNTS LOCALLY...WILL ALSO POSSIBLE IN THE SLOWER
MOVING STORMS.
COME WEDNESDAY...THE WEATHER PATTERN REMAINS SIMILAR...WITH THE
UPPER TROUGH SHIFTING MORE TOWARDS THE COASTAL PLAIN...BUT ALSO
BECOMING MORE BROADENED BY EVENING. WE WILL ALSO SEE A COLD FRONT
MAKE ITS WAY SOUTHWARD FROM THE GREAT LAKES REGION INTO THE OHIO
RIVER VALLEY. IMPACTS FOR OUR AREA REMAIN RELATIVELY UNCHANGED...
WITH SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. WITH THE TROUGH
BECOMING LESS PRONOUNCED ACROSS OUR AREA...AFTERNOON TEMPERATURES
WILL ALSO BE TWO OR THREE DEGREES WARMER THAN THOSE FORECAST FOR
TUESDAY.
ON THURSDAY...THE UPPER TROUGH REALLY BREAKS DOWN...AND RIDGING FROM
THE SOUTHWEST BEGINS TO BUILD INTO OUR AREA. THIS RIDGING WILL WARM
THE MID AND UPPER LEVELS OF THE ATMOSPHERE...HELPING TO LIMIT THE
DEVELOPMENT OF THUNDERSTORMS DURING THE AFTERNOON AND EVENING...
ALTHOUGH WE WILL STILL SEE A FEW. FORECAST MODELS ARE ALSO IN
AGREEMENT THAT THE COLD FRONT WILL STALL SOMEWHERE BETWEEN THE OHIO
RIVER VALLEY AND THE VIRGINIA/NORTH CAROLINA STATE LINE...ALTHOUGH
ITS HARD TO BE MORE SPECIFIC AT THIS POINT BECAUSE THE BOUNDARY
BECOMES SO DIFFUSE. AT ANY RATE...UPPER RIDGING WILL ALSO SUPPORT A
CONTINUED WARMUP FOR OUR AREA...WITH MID AND UPPER 80S EXPECTED FOR
THE MOUNTAINS...AND UPPER 80S TO LOW 90S FOR THE PIEDMONTS.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 330 PM EDT SUNDAY...
THE UPPER TROUGH BEGINS TO LIFT OUT AS HEIGHTS INCREASE WITH THE
HEARTLAND RIDGE AND THE BERMUDA HIGH JOINING FORCES. THIS WILL
ALLOW THE TEMPERATURE AND DEWPOINT TO CLIMB TOWARDS UNCOMFORTABLE
LEVELS AGAIN INTO NEXT WEEKEND. INITIALLY POP UP STORMS CAN BE
EXPECTED WITH INCREASING INSTABILITY...THEN A BETTER CHANCE OF
THUNDERSTORMS EXISTS AT THE END OF THE FORECAST WITH ANOTHER COLD
FRONT DROPPING OUT OF THE OHIO VALLEY AND GREAT LAKES.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1245 PM EDT MONDAY...
WIDELY SCATTERED...SLOW MOVING SHOWERS AND STORMS...WILL CONTINUE
TO POP UP AND MOVE LITTLE THROUGH EARLY THIS EVENING RESULTING IN
POCKETS OF HEAVY RAINFALL IN A FEW SPOTS. STILL IFFY AS TO WHETHER
ANY HEAVIER SHRA/TSRA WILL IMPACT ANY OF THE AIRPORTS...SO
INCLUDING A VCTS OR VCSH MENTION UNLESS CONVECTION IS NEAR A TAF
SITE AT RELEASE WHICH WOULD WARRANT MORE PREVAILING LOWER
CONDITIONS. OTRW RUNNING WITH MAINLY VFR 4-6K FT CIGS THIS
AFTERNOON OUTSIDE OF CONVECTION WITH CB BUILDUPS ALONG THE BLUE
RIDGE.
STORMS FADE SOME EARLY THIS EVENING BUT MAY TEND TO REGENERATE
ALONG THE BLUE RIDGE WHERE LOW LEVEL EASTERLY FLOW WILL PERSIST
AHEAD OF ANOTHER WEAK MID LEVEL WAVE CROSSING FROM THE WEST
OVERNIGHT. THEREFORE INCLUDED A VCSH MENTION AT A FEW
LOCATIONS...MAINLY KROA/KBCB WHERE GUIDANCE SHOWS A SWATH OF SHRA
LINGERING PAST MIDNIGHT. ALSO ADDED SOME LOWER MVFR CIGS IN SPOTS
WHILE KEEPING FOG AT IFR LEVELS AT LWB/BCB...AND MVFR OUT EAST AS
WELL AS KBLF WHERE CONFIDENCE IN FOG/STRATUS REMAINS LOW.
LOW CIGS AND FOG SHOULD SLOWLY BURN AWAY TUESDAY MORNING BUT MAY
TAKE UNTIL LATE MORNING FOR A RETURN TO VFR IN THE VALLEY
LOCATIONS. HOWEVER ANY HEATING WILL AGAIN RESULT IN BKN CU FIELDS
BY MIDDAY WITH YET ANOTHER WAVE TO THE SOUTH BRINGING AN EVEN
BETTER COVERAGE OF SHRA/TSRA FOR THE AFTERNOON AND EVENING ON
TUESDAY.
THE DAILY AFTERNOON AND EVENING THREAT OF SHOWERS AND
THUNDERSTORMS CONTINUES THROUGH THE WEEK BUT SHOULD BECOME MORE
ISOLATED FROM MIDWEEK ON AS WEAK HIGH PRESSURE SETTLES IN FROM
THE WEST BY WEEKS END. OUTSIDE OF THIS MAINLY DIURNALLY DRIVEN
CONVECTION...THE ONLY OTHER FLIGHT WEATHER HAZARDS WOULD BE FROM
OVERNIGHT VALLEY FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/PM/WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...JH/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
958 AM EDT MON JUL 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL DRIFT EAST TO OFF THE MID ATLANTIC COAST THIS
AFTERNOON. RETURN SOUTHEAST FLOW AROUND THE HIGH WILL BRING
INCREASING MOISTURE INTO TONIGHT. AN UPPER LEVEL TROUGH OF LOW
PRESSURE WILL THEN RESIDE OVER THE EASTERN UNITED STATES...YIELDING
THE POTENTIAL FOR UNSETTLED WEATHER INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 925 AM EDT MONDAY...
ISOLATED SHOWERS CONTINUE TO LINGER ALONG THE EASTERN SLOPES AIDED
BY WEAK SE FLOW INTO THE BLUE RIDGE AND LOW LEVEL THETA-E GRADIENT
PARKED ALONG RIDGES. HOWEVER MORNING RAOBS SHOW THAT THE MOISTURE
REMAINS QUITE SHALLOW IN THE ZONE OF EASTERLY FLOW...CAPPED BY VERY
DRY AIR ALOFT WITH ONLY VERY WEAK MID LEVEL STEERING. THIS
SUPPORTS ADDED SLOW MOVING HEAVY RAIN PRODUCING SHRA/TSRA BUT
EXPECT COVERAGE TO BE LIMITED SOMEWHAT BY LACK OF MUCH SUPPORT
GIVEN PASSAGE OF ONE S/W ATTM AND ONLY FAINT ENERGY SPILLING IN
FROM THE WEST THIS AFTERNOON. LATEST FORECAST SOUNDINGS DO SHOW
THE CAP SLOWLY ERODING OVER THE WEST LATER ON WITH MOST LOCAL
MODELS AS WELL AS THE HRRR PRODUCING A SCATTERING OF CONVECTION
MAINLY MOUNTAINS. THUS BUMPED UP POPS SOME ACROSS THE WEST ESPCLY
BLUE RIDGE TO INIT AND INCLUDED A BRIEF HEAVY RAIN MENTION FOR
SLOW MOVING STORMS. ANY SVR SHOULD BE ISOLATED AND MAINLY WHERE
HELPED BY PRECIP LOADING PER HIGH WINDEX/DCAPE VALUES OFF MODIFIED
RAOBS. OTRW MAINLY PC WITH PLENTY OF CU AROUND AS MOISTURE SLOWLY
RETURNS. MORNING THICKNESS SUPPORTING HIGHS MOSTLY IN THE 80S BUT
MAYBE NOT QUITE AS WARM IN SPOTS SO TWEAKED DOWN RANGES A BIT.
PREVIOUS DISCUSSION AS OF 725 AM EDT MONDAY...
SHORTWAVE MOVING ACROSS ERN TN ATTM...WITH EASTERLY FLOW INTO THE
MTNS STILL KEEPING SHOWERS/FEW TSRA GOING FROM SOUTH OF ROANOKE TO
JUST SOUTH OF THE VA BORDER ALONG ROCKINGHAM/STOKES COUNTY LINE.
WILL SEE THE ACTIVITY CONTINUE UNTIL SHORTWAVE INFLUENCE
PASSES...ALTHOUGH WINDOW WILL BE SHORT AS ANOTHER SHORTWAVE HEADS
INTO THE COALFIELDS OF ERN KY BY 18Z TODAY. ADJUSTED POPS TO
ACCOUNT FOR THIS AND UPPED TEMPS THIS MORNING AS MORE CLOUD COVER
HAS KEPT TEMPS IN THE MID 60S TO AROUND 70.
PREVIOUS VALID DISCUSSION...
SHORTWAVE SINKS SOUTHEAST INTO GA/SC BY MIDDAY AND SHOULD TAKE
MOST OF THE HIGH CLOUDS WITH IT. ANOTHER WAVE PUSHES EAST OUT OF
THE OHIO VALLEY INTO THE BLUE RIDGE THIS AFTERNOON AND WITH UPPER
TROUGH OVERHEAD WITH UPPER DIVERGENCE AHEAD OF 80 KNOT
JET...SHOULD SEE ENOUGH LIFT TO INDUCE SCATTERED STORMS AFTER
MIDDAY. THE 00Z GFS/12Z ECMWF SEEM TO BE IN THE SAME CAMP IN
REGARDS TO THE UPPER LEVEL FEATURES AND TRY TO AIM THE BEST
COVERAGE OF SHOWERS AND STORMS FROM THE ALLEGHANY HIGHLANDS/WV
MTNS SOUTHEAST ALONG THE BLUE RIDGE. KEPT HIGHER POPS HERE WITH A
LESSER THREAT OVER THE PIEDMONT OF NC. WITH FLOW IN THE LOWEST
5KFT EAST TO SOUTHEAST AND WEST TO NW FLOW ALOFT SOME OF THESE
STORMS THAT FORM COULD BE ANCHORED TO THE RIDGES...RESULTING IN
POTENTIALLY HEAVIER RAIN AND POSSIBLE ISOLATED FLOODING...ALTHOUGH
PWATS ARE NOT AS HIGH AS A FEW DAYS AGO RANGING FROM 1 TO 1.4
INCHES.
TONIGHT...ONE SHORTWAVE EXITS WITH THE NEXT UPSTREAM WAVE MOVING
TOWARD THE TN VALLEY INTO THE SRN APPALACHIANS. GFS/ECMWF/SREF
LINGER THE CHANCES OF SHRA/TSRA ACROSS THE AREA THROUGH THE NIGHT
MAINLY ALONG EITHER SIDE OF THE BLUE RIDGE WHERE BEST CONVERGENCE
LIES. LOWERED POPS TO 30 AROUND THE BLUE RIDGE WITH SLIGHT CHANCE
EITHER SIDE.
FOR TEMPS...TODAY WILL SEE INCREASING HUMIDITY IN THE EAST PER SE
FLOW AND WITH CLOUDS FORMING FASTER...THINK MET MOS MAY HAVE BETTER
RESULTS WHICH IS A DEGREE OR THREE COOLER THAN MAV MOS. HIGHS WILL
RANGE FROM NEAR 90 EAST AND IN THE ROA/SRN SHENANDOAH VALLEYS TO
LOWER TO MID 80S WEST.
TONIGHT...THE FLOW IS WEAK AT THE SFC SO THINK LOWS SHOULD BE
SIMILAR TO THIS MORNING WITH 60S CWA WIDE...LOWER IN THE WEST.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 340 AM EDT SUNDAY...
WILL START OUT THE DAY TUESDAY WITH THE PERSISTENT UPPER LEVEL
TROUGH DRIFTING SLOWLY TO THE EAST...BUT STILL SITUATED ALMOST
DIRECTLY OVER OUR AREA. THE SUBTLE UPPER DISTURBANCES RIDING INTO
THE BASE OF THE TROUGH FROM THE MIDWEST WILL TRIGGER ANOTHER ROUND
OF SCATTERED THUNDERSTORM ACTIVITY...INITIALLY DEVELOPING OVER THE
MOUNTAINS WITH SUPPORT FROM CONVERGENCE ALONG THE RIDGELINES...BUT
THEN SPREADING INTO THE PIEDMONTS AS AFTERNOON HEATING MAXIMIZES. AS
HAS BEEN TYPICAL OVER THE PAST SEVERAL WEEKS...A FEW OF THESE STORMS
WILL BECOME SEVERE...LIKELY WITHIN MINUTES OF DEVELOPING...WITH
DAMAGING WINDS AS THE GREATEST THREAT. PERIODS OF HEAVY RAIN...WITH
2 TO 3 INCH AMOUNTS LOCALLY...WILL ALSO POSSIBLE IN THE SLOWER
MOVING STORMS.
COME WEDNESDAY...THE WEATHER PATTERN REMAINS SIMILAR...WITH THE
UPPER TROUGH SHIFTING MORE TOWARDS THE COASTAL PLAIN...BUT ALSO
BECOMING MORE BROADENED BY EVENING. WE WILL ALSO SEE A COLD FRONT
MAKE ITS WAY SOUTHWARD FROM THE GREAT LAKES REGION INTO THE OHIO
RIVER VALLEY. IMPACTS FOR OUR AREA REMAIN RELATIVELY UNCHANGED...
WITH SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. WITH THE TROUGH
BECOMING LESS PRONOUNCED ACROSS OUR AREA...AFTERNOON TEMPERATURES
WILL ALSO BE TWO OR THREE DEGREES WARMER THAN THOSE FORECAST FOR
TUESDAY.
ON THURSDAY...THE UPPER TROUGH REALLY BREAKS DOWN...AND RIDGING FROM
THE SOUTHWEST BEGINS TO BUILD INTO OUR AREA. THIS RIDGING WILL WARM
THE MID AND UPPER LEVELS OF THE ATMOSPHERE...HELPING TO LIMIT THE
DEVELOPMENT OF THUNDERSTORMS DURING THE AFTERNOON AND EVENING...
ALTHOUGH WE WILL STILL SEE A FEW. FORECAST MODELS ARE ALSO IN
AGREEMENT THAT THE COLD FRONT WILL STALL SOMEWHERE BETWEEN THE OHIO
RIVER VALLEY AND THE VIRGINIA/NORTH CAROLINA STATE LINE...ALTHOUGH
ITS HARD TO BE MORE SPECIFIC AT THIS POINT BECAUSE THE BOUNDARY
BECOMES SO DIFFUSE. AT ANY RATE...UPPER RIDGING WILL ALSO SUPPORT A
CONTINUED WARMUP FOR OUR AREA...WITH MID AND UPPER 80S EXPECTED FOR
THE MOUNTAINS...AND UPPER 80S TO LOW 90S FOR THE PIEDMONTS.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 330 PM EDT SUNDAY...
THE UPPER TROUGH BEGINS TO LIFT OUT AS HEIGHTS INCREASE WITH THE
HEARTLAND RIDGE AND THE BERMUDA HIGH JOINING FORCES. THIS WILL
ALLOW THE TEMPERATURE AND DEWPOINT TO CLIMB TOWARDS UNCOMFORTABLE
LEVELS AGAIN INTO NEXT WEEKEND. INITIALLY POP UP STORMS CAN BE
EXPECTED WITH INCREASING INSTABILITY...THEN A BETTER CHANCE OF
THUNDERSTORMS EXISTS AT THE END OF THE FORECAST WITH ANOTHER COLD
FRONT DROPPING OUT OF THE OHIO VALLEY AND GREAT LAKES.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
AS OF 725 AM EDT MONDAY...
SHOWERS SOUTH OF ROANOKE SHOULD STAY THERE THIS MORNING BUT WILL
SEE COVERAGE INCREASING ACROSS THE MTNS THIS AFTERNOON. HAVE
ENOUGH CONFIDENCE THAT MOST PLACES WILL SEE A SHOWER OR
THUNDERSTORM IN THE VICINITY OF THE TERMINAL FOR A COUPLE HOURS
AFTER 18Z TODAY...EXCEPT MAYBE DANVILLE. STILL WILL MAINLY KEEP
VFR CONDITIONS GOING.
THE FORECAST TONIGHT WILL BE TRICKY AS THE CONVECTION MAY LINGER
THROUGH EARLY MORNING IN THIS REGIME...ALTHOUGH MODELS SHOW LESS
COVERAGE. WITH THIS IN MIND KEPT FOG AT IFR/MVFR AT LWB/BCB WHICH
IS HIGHER VSBY THAN MODELS FORECASTING.
THE DAILY AFTERNOON AND EVENING THREAT OF SHOWERS AND
THUNDERSTORMS CONTINUES THROUGH THE WEEK. GREATEST COVERAGE OF
SHOWER ACTIVITY WILL BE DURING THE AFTERNOON AND EVENING TUESDAY.
OUTSIDE OF THIS MAINLY DIURNALLY DRIVEN CONVECTION...THE ONLY
OTHER FLIGHT WEATHER HAZARDS WOULD BE FROM OVERNIGHT VALLEY FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/PM/WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...WP
AREA FORECAST DISCUSSION
NWS SPOKANE WA
450 PM PDT Tue Jul 31 2012
.SYNOPSIS...
An upper level low currently over the Gulf of Alaska will drop
southwest over the next couple days resulting in only a small
chance of thunderstorms near the Canadian border. Drier northwest
flow will spill into the region Thursday evening and continue
through Saturday resulting in dry but locally breezy weather.
Warmer and increasingly unsettled conditions could return to the
region by Sunday and continuing into early next week.
&&
.DISCUSSION...
Tonight...Weak upper level shortwave trough continues to cross
Washington this evening and should move into north Idaho around
sunset. The big question is will this disturbance be able to
trigger a thunderstorm or two. The latest instability numbers from
the RUC and LAPS are not terribly impressive...however small
pockets of CAPEs around 500 j/kg are located near the Canadian
border. The convective caps have been weakening...however up
through now...only small cumulus fields have been forming over the
higher terrain near the US/Canadian border. We will keep a slight
chance of thunder mentioned through early evening near the
international border but the remainder of the forecast area will
be left dry for the night. fx
Wednesday through Friday: Following a quiet, seasonal weather
day on Wednesday, our focus will switch gears toward an upper-
level trough swinging across southern BC...northeastern WA...and
northern ID for Thursday/Thursday night. The midlevel wave will
usher a strong cold front through the region resulting in a
passing shield of clouds, chance for light showers across the
northeastern zones, breezy northerly winds, and a slight chance
for post-frontal convection and perhaps an isolated thunderstorm.
Dry, northerly flow behind Thursday`s shortwave will promote
another day of mostly clear skies and seasonal temperatures.
Overall, models are in general agreement through the period and
confidence is near to above normal.
The center of the upper-low driving the cold front will track S/SE
down the BC/Alberta border. The tail, or southwestern flank of the
strongest synoptic forcing will cross NE WA and N ID Thursday
afternoon. There is a modest moisture fetch that becomes entrained
into the system with precipitable waters of an inch or higher along
the coast...decreasing near 0.80" over N Idaho. Forcing along the
cold front in conjunction with large-scale ascent associated with
differential PVA will lead to a layer saturation and band of thick
clouds passing with the initial 700-500mb cold front. Light showers
will be possible within this band but the threat for thunderstorms
will be low. As the 500mb cold pool slides over the northeastern
zones in the post-frontal air mass Thursday afternoon... there is a
chance for convection to fire with forecast soundings via the GFS
even supporting a few thunderstorms. The NAM on the other hand, is
much quicker to bring a midlevel dry slot into the northeastern
zones quickly shutting down any chance for afternoon convection.
Given the better agreement amongst the GFS/ECMWF we have trended
the forecast toward the latter keeping a slight chance for
thunderstorms...but confidence is generally below normal related to
the thunder threat.
The pattern would also favor breezy to gusty winds for the
Okanogan Valley given the north to south pressure gradient and
cold advection. Consequently, we have increased winds above model
guidance to sustained speeds of 10-18 mph with gusts in the 20-30
mph range. While these winds are well below any highlight-able
thresholds...it will present an elevated threat for wildfire
growth in grass, brush, and other fine fuels given the combination
of relative humidities in the 20`s. /sb
Friday night through Tuesday: Trough continues to exit to the east
along the US/Canadian boarder. A ridge builds in. The thermal
trough that has been suppressed to the south for the last several
days will once again set up across the intermountain west.
Daytime temperatures will warm to slightly above average temps by
Saturday. Sunday will be the warmest day with temps 5-9 degrees
above average. Monday and Tuesday we will remain above average as
well. There are still some model discrepancies of what do do with
a low that develops off the northern CA coast. The 12z ECMWF is
not as bullish in bringing the low across the entire Pac NW as a
weaker open wave. It does show a very weak wave and associated
moisture moving up from the desert southwest. It also shows a strong
closed low moving south out of Canada and has it moving across
northern WA and ID starting early Tuesday. The GFS on the other
hand brings some energy and moisture from the desert southwest
into our southeastern WA and central ID areas. The possible low
from Canada stays way to the north and has no real weather impact
on us. Given both models do show the possible monsoonal moisture
streaming up with a disturbance, have decided to keep the mention
of thunderstorms across the Blue Mountains and the Camas Prairie
for Sunday and have increased cloud cover a bit. /Nisbet
&&
.AVIATION...
00Z TAFS...A weak upper level disturbance will track through E WA
and N ID through 03z-05z. This will result in a slight chance of
-tsra near the Canadian border...but little chance at the TAF sites.
Forecast will be clear with diurnal winds and VFR conditions through
00z Thursday. Tobin
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 56 84 58 83 55 84 / 0 0 0 10 10 10
Coeur d`Alene 55 84 57 80 53 84 / 0 0 0 10 10 10
Pullman 49 82 51 80 49 82 / 0 0 0 10 0 0
Lewiston 60 90 62 90 61 90 / 0 0 0 0 0 0
Colville 52 88 56 85 51 89 / 0 0 10 20 10 10
Sandpoint 49 84 52 80 49 84 / 0 0 10 20 20 10
Kellogg 53 84 53 79 51 81 / 10 0 0 10 10 10
Moses Lake 56 89 60 88 57 89 / 0 0 0 0 0 0
Wenatchee 61 88 63 88 62 91 / 0 0 0 0 0 0
Omak 60 89 59 86 55 90 / 0 0 10 10 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
247 PM CDT MON JUL 30 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY
247 PM CDT MON JUL 30 2012
MAIN FORECAST CONCERNS ARE ON SHOWER AND THUNDERSTORM CHANCES THIS
EVENING. FOCUS THEN TURNS TO VALLEY FOG POTENTIAL TONIGHT AND AGAIN
WEDNESDAY NIGHT AND SHOWER/THUNDERSTORM CHANCES WEDNESDAY NIGHT
INTO THURSDAY.
LATEST SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
IRONWOOD MICHIGAN...TO NEAR RICE LAKE WISCONSIN...TO NEAR ST.
JAMES MINNESOTA...DRIFTING SOUTHEAST. MESOSCALE FORECAST MODELS
CONTINUE TO SUGGEST THAT SHOWERS AND THUNDERSTORMS WILL FIRE ALONG
THIS FRONT IN THE 4 TO 6 PM TIME FRAME. THIS WOULD PUT THE FRONT
OVER CENTRAL WISCONSIN...EXTENDING SOUTHWEST INTO NORTHEAST IOWA.
LATEST VISIBLE SATELLITE IMAGERY SHOWED A WELL DEFINED CUMULUS
FIELD AHEAD OF THE FRONT. NO PRECIPITATION RETURNS ON RADAR YET
ALONG THIS FIELD. THINKING THE FRONT WILL FINALLY GENERATE
CONVECTION AS IT MOVES INTO CENTRAL AND FAR SOUTHWEST
WISCONSIN...EXTENDING INTO NORTHEAST IOWA. DRY LOW LEVELS WILL LEAD
TO THE POTENTIAL FOR DAMAGING WINDS WITH ANY STORMS THAT DEVELOP.
LATEST RAP ANALYSIS INDICATES NEARLY 1400-1600 DOWNDRAFT CAPE
AHEAD OF THE COLD FRONT. 0-6 KM SHEAR IS RATHER WEAK...GENERALLY
LESS THAN 30 KTS...SO STORMS MAY STRUGGLE TO BECOME ORGANIZED ONCE
THEY DEVELOP. SURFACE BASED CAPE VALUES OF NEARLY 4000 J/KG WILL
LEAD TO STRONG UPDRAFTS...WITH MARGINALLY SEVERE HAIL POSSIBLE.
THE COLD FRONT WILL PUSH EAST OF THE FORECAST AREA LATE THIS EVENING
WITH HIGH PRESSURE BUILDING INTO THE REGION. FORECAST SOUNDINGS ARE
SHOWING THE POTENTIAL FOR SOME VALLEY FOG DEVELOPMENT ALONG THE
MISSISSIPPI RIVER. THE AIR MASS LOOKS A BIT ON THE DRY SIDE FOR THIS
TO OCCUR. TEMPERATURE AND DEW POINT SPREADS AT KLSE APPROACH TWO
DEGREES BUT THIS OCCURS LATE IN THE NIGHT/EARLY MORNING...AROUND
11Z. WINDS ARE MORE FAVORABLE...WITH LIGHT WIND FROM THE SURFACE
THROUGH 2 KFT. THINKING A BRIEF PERIOD OF PATCHY VALLEY FOG IS
POSSIBLE TONIGHT...ESPECIALLY IF ANY PRECIPITATION FALLS THIS
EVENING. ANOTHER FACTOR POSSIBLY WORKING AGAINST VALLEY FOG IS A LOW
CLOUD DECK APPROACHING THE FORECAST AREA BEHIND THE COLD FRONT.
THESE CLOUDS LOOK TO PASS JUST EAST OF THE MISSISSIPPI SO WILL HAVE
TO KEEP A CLOSE WATCH ON THESE. OTHERWISE...PLAN ON SKIES RANGING
FROM MOSTLY CLEAR TO PARTLY CLOUD DURING THE OVERNIGHT HORUS. LOOK
FOR LOW TEMPERATURES WILL RANG FROM LOWER 60S ACROSS NORTHERN
WISCONSIN TO THE UPPER 60 OVER NORTHEAST IOWA.
SLIGHTLY COOLER AIR WILL MOVE INTO THE REGION BEHIND THE FRONT LATE
TONIGHT INTO TUESDAY. 850 MB TEMPERATURES WILL FALL FROM 22C MONDAY
AFTERNOON INTO THE 14 TO 16 C RANGE BY EARLY TUESDAY MORNING. HIGH
PRESSURE WILL BE IN CONTROL THROUGH THE DAY ON TUESDAY PROVIDING
MOSTLY SUNNY SKIES. PLAN ON HIGHS RANGING FROM THE LOWER 80S ACROSS
NORTHERN WISCONSIN TO THE UPPER 80S OVER NORTHEAST IOWA.
HIGH PRESSURE IS EXPECTED TO SLIDE EAST OF THE FORECAST AREA TUESDAY
NIGHT INTO WEDNESDAY MORNING AS ANOTHER COLD FRONT APPROACHES FROM
WESTERN MINNESOTA AND EAST SOUTH DAKOTA. FORECAST SOUNDINGS AGAIN
SHOW THE POTENTIAL FOR SOME VALLEY FOG. HIGH PRESSURE WILL BE
SETTLED OVER THE AREA DURING THE OVERNIGHT HOURS PROVIDING LIGHT AND
VARIABLE WINDS. TEMPERATURE/DEW POINT SPREADS APPROACH TWO DEGREES
BY 09Z. WILL HAVE TO KEEP A CLOSE WATCH ON SOME HIGH CLOUDS TRYING
TO STREAM IN FROM THE WEST. CURRENT THINKING IS THAT AREAS OF FOG
WILL DEVELOP ALONG THE MISSISSIPPI AND WISCONSIN RIVER VALLEY.
FORECAST MODELS ARE SHOWING VERY DRY AIR ADVECTING INTO THE AREA
AHEAD OF THE APPROACHING FRONT. WINDS WILL SHIFT TO THE SOUTHWEST
BY WEDNESDAY AFTERNOON AS THE FRONT APPROACHES. DEW POINTS PLUMMET
AS THIS OCCURS...ESPECIALLY ACROSS NORTHEAST IOWA...PORTIONS OF
SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN. COULD SEE DEW POINTS
FALL INTO THE MID 40S BY THE MID AFTERNOON HOURS. THE COLD FRONT
IS EXPECTED TO MOVE INTO THE AREA LATE WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT AS A SHORTWAVE TROUGH MOVES OVER THE UPPER
MISSISSIPPI RIVER VALLEY. THE FRONT AND SHORTWAVE WILL NOT HAVE
MUCH MOISTURE TO WORK WITH AS THE DRY AIR ADVECTS IN FROM THE
SOUTHWEST...WITH A FAIRLY DEEP ELEVATED MIXED LAYER IN PLACE.
EXPECT TO SEE SOME SHOWERS AND ISOLATED THUNDERSTORMS AS THIS
FEATURE MOVES THROUGH. RATHER HIGH BASED ACTIVITY WITH CLOUD BASES
IN THE 8 TO 10KFT RANGE. GUSTY WINDS WOULD BE A CONCERN WITH ANY
SHOWER/STORM ACTIVITY THAT DEVELOPS. ANOTHER SHORTWAVE IS
EXPECTED TO MOVE OVER THE REGION DURING THE DAY ON THURSDAY.
AGAIN THE ELEVATED MIXED LAYER AND CAPPING WILL BE A FACTOR. 0-3KM
MUCAPE WILL CLIMB TO AROUND 2000 J/KG THURSDAY AFTERNOON BUT
QUICKLY WANES DURING THE AFTERNOON AS WEAK SURFACE HIGH PRESSURE
ATTEMPTS TO BUILD IN FROM THE EAST. WILL MAINTAIN A CHANCE OF
SHOWERS AND THUNDERSTORMS ON THURSDAY GIVEN THE SHORTWAVE MOVING
THROUGH.
.LONG TERM...FRIDAY THROUGH MONDAY
247 PM CDT MON JUL 30 2012
30.12 MEDIUM RANGE MODELS IN AGREEMENT FRIDAY INTO
SATURDAY...SHOWING A POTENT UPPER LEVEL TROUGH MOVING ACROSS THE
DAKOTAS AND PUSHING INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE
TROUGH IS EXPECTED TO CLOSE INTO AN UPPER LOW OVER EASTERN NORTH
DAKOTA/NORTHERN MINNESOTA DURING THE DAY ON SATURDAY...PUSHING A
COLD FRONT ACROSS THE AREA. GIVEN THE STRONG DYNAMICS OF THIS SYSTEM
AND STRONG MOISTURE RETURN AHEAD OF IT...FOCUSED INTO THE FORECAST
AREA...A SEVERE WEATHER EVENT LOOKS POSSIBLE. TIMING OF THE FRONT
AND ANY MCS ACTIVITY AHEAD OF IT WILL HAVE AN IMPACT ON CONVECTION
OVER THE FORECAST AREA. EXACT DETAILS ARE UNCLEAR AT THIS TIME BUT
WILL HAVE TO KEEP A VERY CLOSE WATCH ON THE NEXT FEW FORECAST MODEL
RUNS. CURRENT THINKING IS THAT THE AREA COULD SEE AN MCS MOVE
THROUGH SATURDAY MORNING...WITH STORMS REDEVELOPING ALONG THE COLD
FRONT SATURDAY AFTERNOON. PLAN ON HIGHS ON FRIDAY RANGING FORM THE
LOWER 80S OVER NORTHERN WISCONSIN TO THE MID 80S ACROSS NORTHEAST
IOWA. LOOK FOR OVERNIGHT LOWS IN THE 60S. SLIGHTLY COOLER AIR WILL
MOVE IN BEHIND THE FRONT ON SUNDAY WITH HIGHS FALLING INTO THE 70S
TO LOWER 80S.
&&
.AVIATION...THROUGH 18Z TUESDAY
1228 PM CDT MON JUL 30 2012
SHORT WAVE TROUGH MOVING SOUTHEAST ACROSS LAKE SUPERIOR INTO THE
GREAT LAKES REGION THIS AFTERNOON/EVENING. TRAILING COLD FRONT
EXPECTED TO PASS BOTH TAF LOCATIONS DURING THE AFTERNOON. AT THIS
TIME...IT APPEARS THE FRONT WILL BE PAST BEFORE THE PEAK HEATING
CAN BREAK THE CONVECTIVE CAP...SO DID NOT INCLUDE ANY SHRA/TSRA IN
THE TAF LOCATIONS. FEEL IF CONVECTION DEVELOPS IT WILL BE SOUTH
AND SOUTHEAST OF THE AIRFIELDS. HOWEVER...THERE IS A BAND OF MVFR
STRATO-CUMULUS SHOWING UP WITH THE FRONT. THIS MAY BRIEFLY DROP
EACH TAF LOCATION TO A MVFR CEILING FOR 60-90 MINUTES. BEHIND THE
FRONT...EXPECT NORTHWEST WINDS TO BE A BIT GUSTY...BUT GUSTS OVER
G20KT ARE NOT ANTICIPATED. ENOUGH OF A NORTH-NORTHWEST BREEZE WILL
OCCUR OVERNIGHT SO THAT FOG WILL NOT BE AN ISSUE...BUT IF WINDS DO
DIE OFF ENOUGH FOR THE ATMOSPHERE TO DECOUPLE THERE COULD BE SOME
LIGHT FOG/MIST WITH 4-6SM VISIBILITY. LATER SHIFTS WILL MONITOR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
247 PM CDT MON JUL 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...MW
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1156 AM CDT MON JUL 30 2012
.UPDATE...
TEMPS AND DEWPOINTS HAVE BEEN MOSTLY ON TRACK SO FAR. MAIN CONCERN
HAS BEEN THUNDERSTORM POTENTIAL AND SEVERE RISK THIS AFTN/EVENING. SHOT
OF WARM AIR IN MIDLEVELS WILL LIMIT CONVECTION THIS
AFTERNOON...BUT 700MB TEMPERATURES FALL A BIT GOING INTO THE
EVENING PARTICULARLY OVER EASTERN CWA. 11Z HRRR DEVELOPS THUNDER
ALONG SURFACE BOUNDARY AROUND 5 PM WHICH SEEMS REASONABLE.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE DAY TUESDAY. ONLY
EXCEPTION WOULD BE THIS EVENING WITH A CHANCE OF THUNDERSTORMS.
CERTAINLY A POSSIBILITY OF IFR TO MVFR VSBYS WITHIN HEAVIER
RAINFALL. MONITORING THE POTENTIAL FOR SEVERE STORMS AS WELL...WITH
LARGE HAIL AND DAMAGING WINDS THE PRIMARY THREATS. WILL PROBABLY
LEAVE VCTS IN TAFS FOR NOW UNTIL CONFIDENCE IN AREAL COVERAGE OF
STORMS INCREASES. BEST CHANCE FOR STORMS STILL SEEMS TO BE IN THE
22Z-03Z RANGE ACROSS SOUTHERN WISCONSIN.
QUIET WEATHER THEN EXPECTED THROUGH TUESDAY AFTER SHOWERS AND STORMS
WIND DOWN LATE THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 344 AM CDT MON JUL 30 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH
MID LEVEL CLOUDS TO GRADUALLY CLEAR TO THE SE THROUGH ABOUT 15Z.
SWLY WINDS AND WARM ADVECTION TO THEN ENSUE AS LOW PRESSURE AND ITS
SHORTWAVE TROUGH ALONG THE MN/CANADIAN BORDER MOVE THROUGH THE NRN
GREAT LAKES TODAY AND TNT. THE 850-700 MB THERMAL RIDGE WILL SETTLE
OVER THE AREA BY LATE AFTERNOON WITH MODEL AVERAGE 925/850MB TEMPS
SUGGESTING LOWER TO MID 90S FOR HIGHS. HEAT INDEX VALUES WILL BE
SLIGHTLY HIGHER BUT ANY 100 DEGREE READINGS SHOULD BE BRIEF AND
ISOLATED. THE SWLY WINDS WILL KEEP THE LAKE BREEZE CLOSE TO THE LAKE
TODAY.
A WEAK COLD FRONT WILL THEN APPROACH CENTRAL WI TOWARD 00Z AND
SLOWLY PROGRESS ACROSS SRN WI TNT. LOW TO MID LEVEL Q-VECTORS AND
FRONTOGENESIS/CONVERGENCE DO SHOW SOME LIFT WHILE THE AREA WILL BE
AIDED ALOFT BY SOME DIFFERENTIAL PVA FROM THE SHORTWAVE TROUGH
MOVING ACROSS THE NRN GREAT LAKES. MLCAPE/MUCAPE VALUES WILL RANGE
FROM 1500-2500 J/KG IN AN ENVIRONMENT OF 35 KTS OF DEEP LAYER SHEAR
AND HELICITIES SUFFICIENT FOR SUPERCELLS. THUS INCREASED POPS TO
30-50 PERCENT WITH BEST CHANCES TOWARD EAST CENTRAL WI WHERE SCT
TSTORMS WILL OCCUR CLOSER TO MAXIMUM HEATING DURING THE EARLY
EVENING WHILE THEY WILL OCCUR MORE TOWARD MID TO LATE EVENING
FARTHER SOUTH. SVR THREAT WILL THUS BE A LITTLE HIGHER TOWARD EAST
CENTRAL WI WITH PRIMARY THREATS OF DAMAGAGING WINDS AND LARGE HAIL.
HIGH LCL HTS OF 6-7 KFT SHOULD LIMIT THE TORNADO THREAT.
SHORT TERM...TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST
CONFIDENCE IS MEDIUM.
SHORT TERM MODELS INDICATING NORTHWEST FLOW IN THE MIDDLE TO
UPPER LEVELS LINGERING ACROSS THE REGION DURING THIS PERIOD. COLD
FRONT SHIFTS SOUTHEAST OF THE AREA TUESDAY MORNING...WITH THE
PASSING SHORTWAVE TROUGH CLEARING THE AREA BY 18Z TUESDAY. MAY SEE
SOME LINGERING CLOUDS BEFORE THE SHORTWAVE CLEARS THE AREA IN THE
MORNING.
OTHERWISE...NAM/GFS BRING HIGH PRESSURE SLOWLY SOUTHEAST ACROSS
THE REGION TUESDAY THROUGH WEDNESDAY. THIS FEATURE SHOULD BRING
QUIET WEATHER TO THE AREA. LIGHT WINDS AND MOSTLY CLEAR SKIES
TUESDAY NIGHT WITH LOWER 60S DEWPOINTS SHOULD BRING PATCHY FOG TO
LOW LYING AREAS.
NAM 925MB TEMPERATURES REMAIN IN THE MID 20S CELSIUS RANGE
TUESDAY AND WEDNESDAY...WHICH SHOULD RESULT IN HIGHS IN THE UPPER
80S TO LOWER 90S EACH DAY. ONSHORE WINDS WILL BRING SOMEWHAT
COOLER TEMPERATURES NEAR LAKE MICHIGAN.
NAM/GFS INDICATING WARM AIR ADVECTION ACROSS THE AREA WEDNESDAY
AFTERNOON AND WEDNESDAY NIGHT. SHORTWAVE TROUGH ALSO APPROACHES
THE AREA FROM THE WEST LATE WEDNESDAY NIGHT. SURFACE COLD FRONT
SLOW TO SHIFT SOUTHEAST ACROSS NORTHERN WISCONSIN WEDNESDAY NIGHT.
AREA FORECAST SOUNDINGS FROM NAM/GFS SHOWING SOME MID LEVEL
MOISTURE WEDNESDAY NIGHT WITH WEAK ELEVATED CAPE. KEPT LOW CHANCE
POPS FOR NOW FOR WEDNESDAY NIGHT.
LONG TERM...THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS
MEDIUM.
ECMWF/GFS SHOWING MID TO UPPER LEVEL HIGH OVER WESTERN TEXAS TO
CONTINUE TO FLATTEN OUT THURSDAY AND FRIDAY...ALLOWING MORE ZONAL
FLOW OVER THE WESTERN GREAT LAKES REGION. THIS ALLOWS A WELL
DEFINED SHORTWAVE TROUGH TO SHIFT EAST ACROSS THE DAKOTAS
FRIDAY/FRIDAY NIGHT...AND ACROSS MINNESOTA AND NORTHERN WISCONSIN
SATURDAY/SATURDAY NIGHT. THE GFS IS QUICKER AND NOT AS DEEP WITH
THE SHORTWAVE AS THE ECMWF.
AT THE SURFACE...ECMWF/GFS BRINGS COLD FRONT SOUTH THROUGH THE
AREA WITH SOME QPF LATE THURSDAY INTO THURSDAY NIGHT. THEY THEN
TRY TO BRING A BRIEF DRY PERIOD TO THE AREA FRIDAY. USED CONSENSUS
BLEND WITH POPS AND TEMPERATURES FOR THURSDAY THROUGH FRIDAY GIVEN
SOME DIFFERENCES WITH TIMING OF FEATURES. TEMPERATURES SHOULD
REMAIN NEAR TO SLIGHTLY ABOVE NORMAL.
BOTH MODELS THEN IN GENERAL AGREEMENT WITH STRONG COLD FRONT
SHIFTING EAST THROUGH THE REGION SATURDAY. GIVEN THE STRENGTH OF
THE SHORTWAVE TROUGH MOVING THROUGH THE REGION...THIS SHOULD BE
THE NEXT GOOD SHOT OF PRECIPITATION ACROSS THE AREA. KEPT CHANCE
POPS GOING FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT...WITH DRIER
CONDITIONS RETURNING SUNDAY. GFS ALSO SHOWING GOOD DEEP LAYER
SHEAR THOUGH IS OVERDONE WITH MEAN LAYER CAPE. SEVERE WEATHER
WOULD NOT BE OUT OF THE QUESTION WITH THIS SYSTEM. STILL FAR
OFF...SO WILL SEE HOW THIS SYSTEM DEVELOPS OVER THE NEXT SEVERAL
DAYS. NEAR NORMAL TEMPERATURES ARE EXPECTED.
AVIATION/12Z TAFS/...
BKN MID LEVEL DECK WILL GRADUALLY CLEAR BY MID TO LATE MORNING
HOURS. ONLY A FEW CUMULUS WILL DEVELOP FOR MUCH OF THE DAY WITH
SCT-BKN050-070 DEVELOPING FOR THE EVENING AS A COLD FRONT AND
SCATTERED TSTORMS MOVE THROUGH THE REGION. SKIES WILL CLEAR TOWARD
SUNRISE FOR TUE. VFR CONDITIONS WILL PREVAIL BUT REDUCED CIGS AND
VSBYS WITHIN TSTORMS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WIMBERLEY/DDV
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
TUESDAY THROUGH SUNDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
643 AM CDT MON JUL 30 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
309 AM CDT MON JUL 30 2012
MUCH OF THE SHORT TERM FOCUS IS ON TODAYS FORECAST FOR HIGH
TEMPERATURES AND THE CHANCES FOR THUNDERSTORMS THAT COULD PRODUCE
STRONG WINDS.
CURRENTLY...SKIES HAVE MAINLY CLEARED OUT BESIDES SOME HIGH LEVEL
CLOUDS MOVING ACROSS NORTHEAST IOWA AND SOUTHERN WISCONSIN. WITH
A SURFACE RIDGE AXIS OF HIGH PRESSURE IN PLACE FROM THE GREAT
LAKES WEST THROUGH THE REGION...SHALLOW GROUND/VALLEY FOG HAS
FORMED IN MANY LOW LYING AREAS. FURTHER TO THE NORTHWEST...A COLD
FRONT EXTENDS FROM NORTHWEST OF DULUTH TOWARD NORTHEAST SOUTH
DAKOTA. THIS FRONT WILL BE THE FOCUS FOR CONVECTION TODAY AS IT
DIVES SOUTHEAST THROUGH THE REGION.
SOUTHWESTERLY LOW LEVEL WINDS WILL BE ON THE INCREASE TODAY AHEAD
OF THE FRONT WHICH WILL ADVECT WARMER AIR INTO THE REGION. THE
30.00Z NAM IS THE WARMEST OF THE GUIDANCE WITH 850MB TEMPERATURES
OF AROUND +23C AND 925MB TEMPERATURES REACHING +33C BY MID
AFTERNOON. THE 30.00Z GFS/ECMWF/GEM ARE MORE CONSERVATIVE WITH
850MB TEMPS AROUND +20C AND 925MB TEMPS AROUND +27C TO +30C. THE
MAIN LIMITATION TO TEMPERATURES TODAY WILL AGAIN BE WITH CLOUD
COVER...PARTICULARLY THE HIGH LEVEL BAND OF CLOUDS THAT ARE ON THE
EASTERN NOSE OF A MOISTURE FEED THAT COMES OUT OF THE
GULF...ROUNDS THE WESTERN EDGE OF THE MID LEVEL RIDGE THROUGH
ARIZONA AND THEN ROUNDS THE NORTHERN PERIPHERY OF THE RIDGE ACROSS
THE CENTRAL PLAINS ON INTO IOWA. 30.06Z RAP AND 30.00Z NAM/GFS RH
FIELDS SHOW THIS HIGHER CONCENTRATION OF UPPER LEVEL MOISTURE
TRACKING TO THE SOUTHEAST TODAY...WHICH SHOULD LEAVE MAINLY SUNNY
SKIES TODAY AND ALLOW FOR MOST OF THE AREA TO GET INTO THE LOWER 90S.
THE TIMING OF THE COLD FRONT MOVING THROUGH THIS AFTERNOON WILL BE
IDEAL IN TERMS OF COMING THROUGH DURING PEAK DIURNAL HEATING WHEN
INSTABILITY SHOULD BE MAXIMIZED AT ABOUT 2000 J/KG OF SURFACE
BASED CAPE. THE 30.00Z NAM/GFS/ECMWF/GEM ALL ARE IN REASONABLE
AGREEMENT WITH THIS FROPA TIMING ALONG WITH MUCH OF THE REST OF
THE SETUP FOR TODAY. THE BEST LIFT APPEARS TO SHOW UP ACROSS
NORTHERN WISCONSIN THIS AFTERNOON AND IS MAINLY IN THE LOW LEVELS
WITH SOME WEAK 0-2KM CONVERGENCE AND FRONTOGENESIS SHOWING UP FROM
NORTHEAST WISCONSIN TOWARD LA CROSSE BY AROUND 21Z. THE MAIN
LIMITATIONS WILL BE WITH A 850-700MB CAP THAT WILL SUPPRESS MOST
OF THE CONVECTION UNTIL THE AFTERNOON AND WITH A POOR LOW LEVEL
MOISTURE FEED OUT OF THE NORTHERN PLAINS WHICH WILL KEEP THE
COVERAGE OF THE STORMS DOWN. 30.00Z NAM/GFS BUFKIT SOUNDINGS DO
SHOW A FAVORABLE PROFILE FOR STRONG WINDS ONCE THE CAP BREAKS WITH
AN INVERTED V SOUNDING IN THE AFTERNOON. INCREASING 0-3KM SHEAR TO
AROUND 30-40KTS SHOWS UP ACROSS THE CENTRAL PORTION OF WISCONSIN
ALONG THE FRONT...SO THE THREAT APPEARS TO BE THERE THIS AFTERNOON
FOR SEVERE STORMS THAT PRODUCE DAMAGING WINDS ACROSS MAINLY THE
CENTRAL AND EASTERN PORTIONS OF WISCONSIN. CAN NOT RULE OUT SOME
HAIL GIVEN THE AMOUNT OF INSTABILITY...BUT THE MAIN THREAT SHOULD
BE WITH THE WIND. BY 00Z TONIGHT...THE FRONT SHOULD EXTEND FROM
JUST NORTH OF GREEN BAY TO JUST SOUTH OF LA CROSSE AND INTO
NORTHERN ILLINOIS BY MIDNIGHT. PRECIPITATION CHANCE-WISE...THE
MAIN QUESTION IS WITH COVERAGE AND HOW FAR TO THE WEST WILL THE
CONVECTION DEVELOPING INTO THE STRONGER CAP. ANY STORM DEVELOPMENT
WILL BE MORE ISOLATED THE FURTHER WEST YOU GO WITH MORE WIDESPREAD
STORMS LIKELY TOWARD EASTERN WISCONSIN.
AFTER THE FRONT MOVES THROUGH...A RIDGE OF HIGH PRESSURE SETTLES
IN ACROSS THE REGION FOR TUESDAY BEFORE SHIFTING SOUTH A BIT ON
WEDNESDAY. THE NEXT COLD FRONT WILL BE DROPPING DOWN ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY REGION WEDNESDAY NIGHT AND WILL
BRING THE NEXT CHANCES FOR PRECIPITATION ALONG WITH IT.
TEMPERATURES WILL SLOWLY CLIMB AS THE WINDS SHIFT AROUND TO THE
SOUTH ON WEDNESDAY.
.LONG TERM...THURSDAY THROUGH SUNDAY
309 AM CDT MON JUL 30 2012
AN ACTIVE PATTERN WILL CONTINUE INTO THIS WEEKEND WITH THE MAIN
FEATURE BEING A POTENT LOW PRESSURE SYSTEM THAT WILL MOVE THROUGH
ON SATURDAY. BEFORE THAT THOUGH...A MID LEVEL SHORT WAVE TROUGH
WILL DROP DOWN THROUGH THE NORTHWEST FLOW ON THURSDAY WHILE A COLD
FRONT MOVES THROUGH AT THE SURFACE. HIGH PRESSURE WILL BRIEFLY
BUILD IN AT THE SURFACE FOR FRIDAY BEFORE THE MAIN SHOW RAMPS UP
FRIDAY NIGHT INTO SATURDAY. A CLOSED MID LEVEL LOW WILL TRACK
ACROSS SOUTHERN CANADA OVER THIS TIME FRAME WITH A DEEPENING
SURFACE LOW FORMING ACROSS THE DAKOTAS ON FRIDAY. FAIRLY GOOD
AGREEMENT AMONGST THE LONG TERM 30.00Z GUIDANCE WITH THE
POSITION/TIMING OF THE MID LEVEL CUT OFF LOW AND THE SURFACE
LOW/FRONT SETUP. THE WAY THINGS CURRENTLY LOOK...THERE WOULD BE A
COMPLEX OF STORMS THAT WOULD FORM IN THE EASTERN DAKOTAS FRIDAY
WHICH WOULD THEN TRAVEL EAST THROUGH THE REGION INTO SATURDAY
MORNING. THE SURFACE LOW WOULD THEN BE IN AN OCCLUDING STAGE ON
SATURDAY WITH THE WARM SECTOR MAINLY ACROSS EASTERN WISCONSIN AND
THE COLD FRONT NEAR THE MISSISSIPPI RIVER BY 18Z. LOTS OF DETAILS
TO STILL BE HASHED OUT...BUT THIS SYSTEM WILL BRING THE BEST
CHANCES FOR HEAVY RAINFALL OVER THE NEXT WEEK.
&&
.AVIATION...TODAY AND TONIGHT
643 AM CDT MON JUL 30 2012
FORECAST CONCERNS ARE FOCUSED ON NEAR TERM FOG/STRATUS...FRONTAL
PASSAGE THIS AFTERNOON...AND FOG POTENTIAL AGAIN OVERNIGHT.
AS OF 12Z...FOG/STRATUS BEGINNING TO DISSIPATE AT BOTH KRST/KLSE
AND SHOULD COMPLETELY ERODE AROUND 13Z. SURFACE COLD FRONT IS
DRAPED ACROSS NORTH CENTRAL MINNESOTA AND WILL ADVANCE TOWARDS
THE AREA THIS AFTERNOON...CROSSING THE TAF SITES BETWEEN 18Z AND
22Z. ONLY SENSIBLE WEATHER IMPACT IS A NORTHWESTERLY WIND SHIFT...AS
PRECIPITATION CHANCES WILL REMAIN NORTHEAST OF TAF SITES...CLOSER
TO SURFACE LOW AND BETTER FORCING. THERE IS A VERY SMALL CHANCE OF A
SHOWER OR THUNDERSTORM IN THE VICINITY OF KLSE...BUT CONFIDENCE IS
TOO LOW TO INCLUDE IN TAF FORECAST.
HIGH PRESSURE WILL BUILD IN ITS WAKE BY TUESDAY MORNING. GIVEN
WARM RIVER WATER TEMPERATURES AND COOL AIR TEMPERATURES...ANOTHER
ROUND OF FOG/STRATUS WOULD SEEM POSSIBLE. THIS IS ALSO SUGGESTED
BY MOST GUIDANCE...WHICH TAKES CEILINGS AND VISIBILITIES DOWN TO
IFR. HOWEVER...THE SURFACE HIGH POSITION ISN/T THE MOST IDEAL AND
THERE SHOULD BE A STEADY BUT LIGHT NORTHERLY WIND TO KEEP THINGS
MIXED. ALSO...DRIER AIR WORKING IN SHOULD PRECLUDE FOG/STRATUS
FORMING SO FOR NOW HAVE LEFT OUT OF FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
309 AM CDT MON JUL 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
309 AM CDT MON JUL 30 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
309 AM CDT MON JUL 30 2012
MUCH OF THE SHORT TERM FOCUS IS ON TODAYS FORECAST FOR HIGH
TEMPERATURES AND THE CHANCES FOR THUNDERSTORMS THAT COULD PRODUCE
STRONG WINDS.
CURRENTLY...SKIES HAVE MAINLY CLEARED OUT BESIDES SOME HIGH LEVEL
CLOUDS MOVING ACROSS NORTHEAST IOWA AND SOUTHERN WISCONSIN. WITH
A SURFACE RIDGE AXIS OF HIGH PRESSURE IN PLACE FROM THE GREAT
LAKES WEST THROUGH THE REGION...SHALLOW GROUND/VALLEY FOG HAS
FORMED IN MANY LOW LYING AREAS. FURTHER TO THE NORTHWEST...A COLD
FRONT EXTENDS FROM NORTHWEST OF DULUTH TOWARD NORTHEAST SOUTH
DAKOTA. THIS FRONT WILL BE THE FOCUS FOR CONVECTION TODAY AS IT
DIVES SOUTHEAST THROUGH THE REGION.
SOUTHWESTERLY LOW LEVEL WINDS WILL BE ON THE INCREASE TODAY AHEAD
OF THE FRONT WHICH WILL ADVECT WARMER AIR INTO THE REGION. THE
30.00Z NAM IS THE WARMEST OF THE GUIDANCE WITH 850MB TEMPERATURES
OF AROUND +23C AND 925MB TEMPERATURES REACHING +33C BY MID
AFTERNOON. THE 30.00Z GFS/ECMWF/GEM ARE MORE CONSERVATIVE WITH
850MB TEMPS AROUND +20C AND 925MB TEMPS AROUND +27C TO +30C. THE
MAIN LIMITATION TO TEMPERATURES TODAY WILL AGAIN BE WITH CLOUD
COVER...PARTICULARLY THE HIGH LEVEL BAND OF CLOUDS THAT ARE ON THE
EASTERN NOSE OF A MOISTURE FEED THAT COMES OUT OF THE
GULF...ROUNDS THE WESTERN EDGE OF THE MID LEVEL RIDGE THROUGH
ARIZONA AND THEN ROUNDS THE NORTHERN PERIPHERY OF THE RIDGE ACROSS
THE CENTRAL PLAINS ON INTO IOWA. 30.06Z RAP AND 30.00Z NAM/GFS RH
FIELDS SHOW THIS HIGHER CONCENTRATION OF UPPER LEVEL MOISTURE
TRACKING TO THE SOUTHEAST TODAY...WHICH SHOULD LEAVE MAINLY SUNNY
SKIES TODAY AND ALLOW FOR MOST OF THE AREA TO GET INTO THE LOWER 90S.
THE TIMING OF THE COLD FRONT MOVING THROUGH THIS AFTERNOON WILL BE
IDEAL IN TERMS OF COMING THROUGH DURING PEAK DIURNAL HEATING WHEN
INSTABILITY SHOULD BE MAXIMIZED AT ABOUT 2000 J/KG OF SURFACE
BASED CAPE. THE 30.00Z NAM/GFS/ECMWF/GEM ALL ARE IN REASONABLE
AGREEMENT WITH THIS FROPA TIMING ALONG WITH MUCH OF THE REST OF
THE SETUP FOR TODAY. THE BEST LIFT APPEARS TO SHOW UP ACROSS
NORTHERN WISCONSIN THIS AFTERNOON AND IS MAINLY IN THE LOW LEVELS
WITH SOME WEAK 0-2KM CONVERGENCE AND FRONTOGENESIS SHOWING UP FROM
NORTHEAST WISCONSIN TOWARD LA CROSSE BY AROUND 21Z. THE MAIN
LIMITATIONS WILL BE WITH A 850-700MB CAP THAT WILL SUPPRESS MOST
OF THE CONVECTION UNTIL THE AFTERNOON AND WITH A POOR LOW LEVEL
MOISTURE FEED OUT OF THE NORTHERN PLAINS WHICH WILL KEEP THE
COVERAGE OF THE STORMS DOWN. 30.00Z NAM/GFS BUFKIT SOUNDINGS DO
SHOW A FAVORABLE PROFILE FOR STRONG WINDS ONCE THE CAP BREAKS WITH
AN INVERTED V SOUNDING IN THE AFTERNOON. INCREASING 0-3KM SHEAR TO
AROUND 30-40KTS SHOWS UP ACROSS THE CENTRAL PORTION OF WISCONSIN
ALONG THE FRONT...SO THE THREAT APPEARS TO BE THERE THIS AFTERNOON
FOR SEVERE STORMS THAT PRODUCE DAMAGING WINDS ACROSS MAINLY THE
CENTRAL AND EASTERN PORTIONS OF WISCONSIN. CAN NOT RULE OUT SOME
HAIL GIVEN THE AMOUNT OF INSTABILITY...BUT THE MAIN THREAT SHOULD
BE WITH THE WIND. BY 00Z TONIGHT...THE FRONT SHOULD EXTEND FROM
JUST NORTH OF GREEN BAY TO JUST SOUTH OF LA CROSSE AND INTO
NORTHERN ILLINOIS BY MIDNIGHT. PRECIPITATION CHANCE-WISE...THE
MAIN QUESTION IS WITH COVERAGE AND HOW FAR TO THE WEST WILL THE
CONVECTION DEVELOPING INTO THE STRONGER CAP. ANY STORM DEVELOPMENT
WILL BE MORE ISOLATED THE FURTHER WEST YOU GO WITH MORE WIDESPREAD
STORMS LIKELY TOWARD EASTERN WISCONSIN.
AFTER THE FRONT MOVES THROUGH...A RIDGE OF HIGH PRESSURE SETTLES
IN ACROSS THE REGION FOR TUESDAY BEFORE SHIFTING SOUTH A BIT ON
WEDNESDAY. THE NEXT COLD FRONT WILL BE DROPPING DOWN ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY REGION WEDNESDAY NIGHT AND WILL
BRING THE NEXT CHANCES FOR PRECIPITATION ALONG WITH IT.
TEMPERATURES WILL SLOWLY CLIMB AS THE WINDS SHIFT AROUND TO THE
SOUTH ON WEDNESDAY.
.LONG TERM...THURSDAY THROUGH SUNDAY
309 AM CDT MON JUL 30 2012
AN ACTIVE PATTERN WILL CONTINUE INTO THIS WEEKEND WITH THE MAIN
FEATURE BEING A POTENT LOW PRESSURE SYSTEM THAT WILL MOVE THROUGH
ON SATURDAY. BEFORE THAT THOUGH...A MID LEVEL SHORT WAVE TROUGH
WILL DROP DOWN THROUGH THE NORTHWEST FLOW ON THURSDAY WHILE A COLD
FRONT MOVES THROUGH AT THE SURFACE. HIGH PRESSURE WILL BRIEFLY
BUILD IN AT THE SURFACE FOR FRIDAY BEFORE THE MAIN SHOW RAMPS UP
FRIDAY NIGHT INTO SATURDAY. A CLOSED MID LEVEL LOW WILL TRACK
ACROSS SOUTHERN CANADA OVER THIS TIME FRAME WITH A DEEPENING
SURFACE LOW FORMING ACROSS THE DAKOTAS ON FRIDAY. FAIRLY GOOD
AGREEMENT AMONGST THE LONG TERM 30.00Z GUIDANCE WITH THE
POSITION/TIMING OF THE MID LEVEL CUT OFF LOW AND THE SURFACE
LOW/FRONT SETUP. THE WAY THINGS CURRENTLY LOOK...THERE WOULD BE A
COMPLEX OF STORMS THAT WOULD FORM IN THE EASTERN DAKOTAS FRIDAY
WHICH WOULD THEN TRAVEL EAST THROUGH THE REGION INTO SATURDAY
MORNING. THE SURFACE LOW WOULD THEN BE IN AN OCCLUDING STAGE ON
SATURDAY WITH THE WARM SECTOR MAINLY ACROSS EASTERN WISCONSIN AND
THE COLD FRONT NEAR THE MISSISSIPPI RIVER BY 18Z. LOTS OF DETAILS
TO STILL BE HASHED OUT...BUT THIS SYSTEM WILL BRING THE BEST
CHANCES FOR HEAVY RAINFALL OVER THE NEXT WEEK.
&&
.AVIATION...THROUGH 06Z TUESDAY
1202 AM CDT MON JUL 30 2012
WILL CONTINUE TO FORECAST IFR FOG IN THE UPCOMING 06Z TAFS.
TEMPERATURE AND DEW POINT SPREADS ARE 2-4F AT 04Z UNDER CLEAR SKIES
AND CALM WINDS AT BOTH TAF SITES. THIS IS A NICE SETUP FOR IFR FOG
FORMATION. CONFIDENCE TO GO TO AN LIFR FOG EVENT WAS NOT HIGH
ENOUGH BECAUSE THERE ARE SOME UPSTREAM CLOUDS IN THE 10 KFT AND
ABOVE RANGE THAT MAY PLAY A ROLE IN REDUCING THE COOLING SOMEWHAT
IF THEY REMAIN THICK ENOUGH. KTOB TO THE WEST OF KRST FELL TO
1/2SM FAG FROM 10SM IN THE LAST HOUR.
HAVE STILL NOT INCLUDED A TSRA/VATS INTO THE TAF SITES FROM A COLD
FRONTAL PASSAGE BETWEEN 19-22Z. THERE REMAINS INSTABILITY OF
1500-2000 J/KG ON THE FRONT AND CONVERGENCE...BUT LITTLE UPPER
LEVEL SUPPORT FOR WIDESPREAD INITIATION OF TSRA ALONG THE FRONT.
THUS...HAVE KEPT SCT100 DURING FRONTAL PASSAGE FOR NOW. FUTURE
FORECASTS WILL HAVE TO ASSESS THE TSRA POTENTIAL AND CONFIDENCE
FOR POSSIBLE INCLUSION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
309 AM CDT MON JUL 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
310 AM EDT WED AUG 1 2012
.SYNOPSIS...
LOW PRESSURE OVER THE GULF OF MAINE THIS MORNING WILL HEAD FARTHER
OUT TO SEA TODAY. A WEAKENING COLD FRONT WILL BRING SHOWERS AND
THUNDERSTORMS THIS AFTERNOON...ESPECIALLY TO WESTERN NEW ENGLAND.
WARMER AND MORE HUMID WEATHER IS EXPECTED FOR THE MIDDLE AND END
OF THE WEEK ALONG WITH A LOW CHANCE OF SHOWERS AND THUNDERSTORMS
EACH DAY.
&&
.NEAR TERM /THROUGH TODAY/...
310 AM UPDATE...
LAST OF SHOWERS WERE EXITING EASTERN MA COAST AS LOW PRESSURE
HEADS ACROSS GULF OF MAINE EARLY THIS MORNING. CLOUDS REMAIN
LOCKED IN ACROSS REGION FROM LEFTOVER MOISTURE AND CLEARING IS NOT
EXPECTED TO TAKE PLACE UNTIL MID MORNING.
MAIN CONCERN FOR TODAY IS DEVELOPMENT OF SHOWERS/STORMS AS MID
LEVEL TROUGH AND WEAKENING COLD FRONT HEAD E FROM GREAT LAKES.
AIRMASS REMAINS UNSTABLE TO OUR W ACROSS PA WHERE STORMS HAVE
MAINTAINED THEMSELVES MOST OF THE NIGHT. 3KM HRRR BRINGS SOME OF
THIS WEAKENING ACTIVITY INTO WESTERN NEW ENGLAND AROUND 10 AM.
AFTER THAT DEVELOPMENT OF ADDITIONAL CONVECTION WILL DEPEND ON HOW
MUCH INSTABILITY CAN BE GENERATED. 00Z MODELS CONTINUE TO INDICATE
MORE FAVORABLE CONDITIONS WILL REMAIN TO OUR W THIS AFTERNOON...
BUT MARGINAL INSTABILITY COMBINED WITH WEAK CONVERGENCE ALONG
FRONT AND PLENTY OF LOW LEVEL MOISTURE SHOULD GENERATE MORE
SHOWERS AND STORMS ACROSS WESTERN NEW ENGLAND. SEVERE WEATHER
THREAT REMAINS LOW DUE TO WEAK MID LEVEL LAPSE RATES AND WEAK WIND
FIELDS ALOFT.
TOUGH CALL ON FORECAST HIGHS GIVEN UNCERTAINTY WITH CLOUD COVER
TODAY. LOWERED HIGHS SLIGHTLY WITH BLEND OF GFS/NAM MOS...IN 70S
TO MID 80S WITH WARMEST READINGS ACROSS INTERIOR EASTERN MA.
WEAK PRESSURE GRADIENT SHOULD ALLOW SEA BREEZES TO DEVELOP LATER
THIS MORNING. ALSO OF NOTE IS MODERATE RISK OF RIP CURRENTS WHICH
IS BEING FORECAST FOR CAPE COD AND ISLANDS AS WELL AS E MA COAST
TODAY. THIS IS DUE TO WIND WAVES OF 6-8 FT OFFSHORE TRANSITIONING
INTO E/SE SWELL.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
ANY CONVECTION SHOULD DIMINISH THIS EVENING ALBEIT SLOWLY AS
PLENTY OF LOW LEVEL MOISTURE REMAINS IN PLACE. EXPECT RETURN OF
PATCHY LOW CLOUDS AND FOG...ESPECIALLY NEAR COAST WITH LIGHT S/SW
FLOW.
CHANCES FOR SHOWERS/STORMS THU IS LOWER THAN TODAY DESPITE
CONTINUED PRESENCE OF MID LEVEL TROUGH. CROSS SECTIONS SHOW SOME
DRIER AIR WORKING IN ALOFT WHICH SHOULD LIMIT OVERALL CONVECTIVE
POTENTIAL. NONETHELESS WITH S/SW FLOW PROVIDING PLENTY OF LOW
LEVEL MOISTURE AND WEAK BOUNDARY NEARBY...INCLUDED ISOLATED
SHOWERS/STORMS ACROSS INTERIOR THU AFTERNOON. ONCE AGAIN SEVERE
THREAT IS VERY LOW.
ANOTHER LOW IS EXPECTED TO EMERGE OFF CAROLINAS BUT UPPER FLOW IS
PROGRESSIVE ENOUGH TO ALLOW THIS SYSTEM TO PASS WELL SE OF NEW
ENGLAND THU AFTERNOON.
NAM/GFS MOS CLOSE TONIGHT AND THU SO CONTINUED TO RUN WITH A BLEND
OF BOTH. SHOULD COME CLOSE TO 90 THU AFTERNOON IN PARTS OF PIONEER
AND MERRIMACK VALLEYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* HOT AND HUMID CONDITIONS FOR THE END OF THE WEEK INTO THE WEEKEND
* DIURNALLY DRIVEN STORMS PSBL FRIDAY AND SATURDAY
* QUIET WX FOR SUNDAY...COLD FRNT WITH SHOWERS AND THUNDERSTORMS MONDAY
* COOLER AND DRIER WX PSBL BEYOND MONDAY
MODEL DIAGNOSIS...
GENERAL AGREEMENT AMONGST FCST SOLNS CONTINUES TO BE EXHIBITED WITH
INITIAL 01/0Z MODEL GUIDANCE. ONLY SCRUTINY IS A SLIGHTLY FASTER H5
TROF DISTURBANCE ALONG THE US-CANADIAN BORDER AROUND 12Z SATURDAY...
YET BRIEFLY PER 01/0Z GFS WITH THE H5 TROF SLOWING IN ITS APPROACH
EWD AGAINST THE WRN ATLANTIC RIDGE INTO THE END OF THE WEEKEND. THIS
IS NOT SEEN THOUGH IN THE 01/0Z UKMET. AM LEFT TO CONSIDER GREATER
WEIGHT TOWARDS EUROPEAN FCST GUIDANCE...BUT WILL BLEND GFS/NAM FCST
GUIDANCE ACCORDINGLY.
THEREAFTER THERE IS SERIOUS DOUBT WITH THE 01/0Z GFS INVOKING A DEEP
CLOSED LOW ACROSS CENTRAL CANADA GOING AGAINST ITS RESPECTIVE 31/12Z
ENSEMBLE OUTPUT. YET THERE IS SOME UNCERTAINTY WITH THE 31/12Z ECMWF
USHERING THE SRN PLAINS/SRN ROCKIES H5 RIDGE EWD. GLOBAL ENSEMBLE
FCST GUIDANCE IN AGREEMENT OF A NEGATIVE NAO PATTERN FOR THE FIRST
WEEK OF AUGUST...BUT SOLNS BECOME DIVERSE AND THERE IS A LARGE AMNT
OF SPREAD BEYOND. AM EXPECTING A GENERAL TROF PATTERN FOR THE NERN
CONUS INTO THE EARLY PORTION OF NEXT WEEK WITH CONTINUED POS HEIGHT
ANOMALIES AND RIDGING OVER THE WRN ATLANTIC NWD INTO GREENLAND. AS
TO WHETHER THE TROF PATTERN CONTINUES...OR RATHER BREAKS DOWN...
AFTER THE FIRST WEEK OF AUGUST IS FAIRLY UNCERTAIN. AM NOT GIVING
MUCH CONSIDERATION TO THE FCST TUESDAY /7TH/ AND BEYOND.
THURSDAY NIGHT INTO FRIDAY NIGHT...
THE DEPARTURE OF THURS SYSTEM DRAWS WARM MOIST AIR NWD ALONG AND
AHEAD INVOKING POS HEIGHT RISES THRU THE WRN ATLANTIC AND
STRENGTHENING THE BERMUDA HIGH. SUBSEQUENTLY...W/SWLY FLOW IS
ENHANCED ACROSS NEW ENGLAND UNDER A MORE ZONAL FLOW REGIME THEREBY
DRAWING WARM AND MOIST AIR NEWD. MDL FCST SOUNDINGS EXHIBIT CAPPING
AROUND H85 WITH A FAIR AMNT OF ELEVATED INSTABILITY. THERE ARE
SUBTLE HINTS OF WEAK ENERGY ADVECTING THRU THE ZONAL FLOW REGIME
DURING THE DAY FRIDAY...AND WITH THAT BEING SAID THERE IS THE
PLAUSIBILITY OF CONVECTION FORCED VIA CYCLONIC FLOW AND ENHANCED
ASCENT THRU THE CAPPING INVERSION. HEAVY RAIN WILL REMAIN A THREAT
WITH PWAT VALUES AROUND 1.5 INCHES. FEEL ANY CONVECTION WILL BE
ISOLATED /GREATER CHCS ACROSS THE INTERIOR/. AM NOT THINKING
ANYTHING SEVERE. LOOKING AT A VERY HOT AND HUMID DAY FRIDAY.
SATURDAY INTO SATURDAY NIGHT...
FCST GUIDANCE SUGGESTS AN ATTENDANT WEAK WARM FRNTL BOUNDARY PARENT
WITH THE SFC LOW AND H5 TROF ACROSS THE GRT LKS WILL BE THE FOCUS
FOR DIURNALLY FORCED CONVECTION. CAPPING INVERSION AROUND H85 IS
STILL APPARENT AND A STRENGTHENING BERMUDA HIGH TOWARDS THE ERN
CONUS RESULTS IN THE INTRUSION OF DRIER AIR THRU THE MID-LVLS. YET
HEIGHT FALLS ARE EXPECTED ACROSS THE WRN INTERIOR WITH THE APPROACH
OF THE H5 TROF AXIS...AND SHOULD SOME SFC CONVERGENCE PREVAIL ALONG
THE WEAK WARM FRNTL BOUNDARY...FEEL THE WRN INTERIOR WILL HAVE CHC
FOR SHOWERS AND THUNDERSTORMS. NOT COMPLETELY SOLD ON THE OUTCOME...
ITS PSBL THE PERIOD MAY TURN OUT DRY. IF ANY POPS...SLGT CHC. HOT
AND HUMID CONDITIONS CONTINUE FOR THE INTERIOR...COOLER NEAR THE
SHORES.
SUNDAY INTO MONDAY...
SUNDAY APPEARS THE BETTER OF THE TWO DAYS WITH THE RGN FINDING
ITSELF WITHIN THE WARM SECTOR AHEAD OF THE APPROACHING TROF AXIS AND
ATTENDANT COLD FRNT. ANY FORCING MAY BE WELL N OF THE FCST AREA.
OTHERWISE THE MAIN SHOW PREVAILS FOR MONDAY AS A COLD FRNT WITH
SHOWERS AND THUNDERSTORMS SWEEPS THRU THE RGN. AM VERY CONCERNED
WITH THE POSSIBILITY OF HEAVY RAIN AND FLASH FLOODING AS PWATS ARE
ADVERTISED AROUND 2 INCHES /IN SOME CASES 2.5/. NOT CERTAIN STORMS
WILL BE SEVERE /PARAMETERS OF SHEAR APPEAR WEAK WITH MODEST
INSTABILITY THOUGH SKINNY AND THIN THRU THE ATMOS COLUMN/.
TUESDAY AND BEYOND...
WILL PREVAIL A DRY FCST FOR NOW. AS NOTED BY THE PREV FORECASTER...
THE STRONGER WRN ATLANTIC RIDGE MAY SLOW THE PROGRESSION OF THE COLD
FRNT ON MONDAY THEREBY RESULTING IN ACTIVE WX TO LINGER INTO TUE. AS
IT STANDS PRESENTLY...FCST GUIDANCE IS QUICK TO MOVE THE SYS
OFFSHORE AND USHER ACROSS THE RGN COOLER AND DRIER HIGH PRES. WILL
PREVAIL AS SUCH.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE CONFIDENCE...MAINLY THIS MORNING DUE TO
UNCERTAINTY IN HOW QUICKLY CONDITIONS IMPROVE.
IFR/LIFR EXPECTED TO BECOME MORE WIDEPSPREAD BEFORE DAYBREAK...
ALTHOUGH AM MORE CONFIDENT THIS WILL BE CASE NEAR COAST AS OPPOSED
TO INTERIOR. SHOULD SEE IMPROVEMENT TO VFR BY MID TO LATE MORNING
ALTHOUGH CAPE COD TERMINALS MAY REMAIN MVFR OR EVEN IFR THROUGH
MUCH OF DAY WITH LIGHT S/SE FLOW.
SHOWERS AND TSTMS WILL DEVELOP AFTER 16Z ACROSS WESTERN NEW
ENGLAND WITH LOCAL MVFR/IFR. STORMS WILL BE SLOW MOVING WITH HEAVY
RAIN BEING MAIN THREAT. LESSER CHANCE OF TSTMS E OF MHT-ORH-IJD.
LOW CIGS RETURN TONIGHT WITH MVFR/IFR CONDITIONS...LIFR MORE
LIKELY ALONG IMMEDIATE COAST. CIGS LIFT BY MID MORNING THU WITH
VFR EXPECTED THROUGH AFTERNOON. ONLY ANTICIPATE ISOLD
SHOWERS/TSTMS THU AFTERNOON...MAINLY ACROSS INTERIOR.
KBOS TAF...MODERATE CONFIDENCE.
FAIRLY CONFIDENT ON RETURN TO IFR CIGS BEFORE DAYBREAK...BEFORE
CONDITIONS IMPROVE BY MID MORNING. GRADIENT LOOKS WEAK ENOUGH TO
SUPPORT SEA BREEZE BY 15Z. LOW CHANCE OF TSTMS 20Z-23Z.
KBDL TAF...MODERATE CONFIDENCE.
UNCERTAINTY AS TO IFR CIGS DEVELOPING BEFORE DAYBREAK SO TAF
REFLECTS MVFR CIGS. CONDITIONS SHOULD IMPROVE QUICKLY AFTER
SUNRISE. MAIN WINDOW FOR TSTMS 15Z-18Z BUT MAY BE AS LATE AS
18Z-21Z.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY NIGHT...
PSBL CONVECTION FRI ACROSS THE INTERIOR...LOW CONFIDENCE. OTHERWISE
PREVAIL VFR WITH MODEST W/SWLY FLOW. GUSTS OVER SHORELINE TERMINALS
AROUND 20 KTS.
SATURDAY INTO SATURDAY NIGHT...
RENEWED CHCS FOR SHRA/TSRA ACROSS THE INTERIOR...LOW CONFIDENCE. SLY
FLOW WITH GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
COLD FRNT APPROACHES WITH SHRA/TSRA ALONG AND AHEAD. SUNDAY VFR WITH
INCREASING SLY FLOW /GUSTS AROUND 20 KTS/. SHOULD REMAIN DRY.
MONDAY...SHRA/TSRA EXPECTED CLEARING LATE INTO TUE MORN.
&&
.MARINE...
SCA REMAINS POSTED INTO AFTERNOON FOR OUTER WATERS AS WINDS AND
SEAS CONTINUE TO DIMINISH.
WEAKER GRADIENT TODAY AS SURFACE LOW HEADS OUT TO SEA WITH
AFTERNOON SEA BREEZES EXPECTED. S/SW FLOW PREVAILS TONIGHT AND THU
WITH PATCHY LATE NIGHT AND EARLY MORNING FOG.
LOW PRESSURE SHOULD PASS WELL S AND E OF NEW ENGLAND THU BUT WE
MAY SEE SEAS OF 5-6 FT REACH OUTER WATERS.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY NIGHT...
W/SWLY FLOW BECOMING SLY WITH GUSTS AROUND 20 KTS FOR THE S WATERS
WILL INVOKE SEAS OF 5 FT ALL THE WAY INTO THE LOCAL SOUNDS AND BAYS.
NOT EXPECTING ANY STORMS.
SATURDAY INTO SATURDAY NIGHT...
SLY FLOW WILL REMAIN BRISK BUT WEAKER ENOUGH TO ALLOW SWELL TO
DIMINISH. GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
SLY FLOW INCREASING INTO SUNDAY IN RESPONSE TO APPROACHING COLD
FRNT. SEAS BUILDING ALONG THE S AND E WATERS IN RESPONSE. COLD FRNT
TO SLIDE ACROSS THE WATERS LATE MONDAY ALONG AND AHEAD OF WHICH
SHOWERS AND THUNDERSTORMS ARE EXPECTED AND LIKELY TO LINGER INTO THE
TUE MORN HRS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ250-
254-255.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ256.
&&
$$
SYNOPSIS...SIPPRELL/JWD
NEAR TERM...JWD
SHORT TERM...JWD
LONG TERM...SIPPRELL
AVIATION...SIPPRELL/JWD
MARINE...SIPPRELL/JWD
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1252 AM EDT WED AUG 1 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM EAST OF NEW JERSEY WILL MOVE THROUGH THE NEW
ENGLAND COASTAL WATERS TONIGHT. A WEAK COLD FRONT MOVING THROUGH THE
GREAT LAKES WILL DISSIPATE BEFORE REACHING THE FORECAST AREA ON
WEDNESDAY. A SECOND LOW PRESSURE WILL DEVELOP OVER THE SOUTHEAST
STATES WEDNESDAY AND TRACK WELL OFF THE NEW JERSEY COAST ON
THURSDAY. A BERMUDA HIGH PRESSURE SYSTEM WILL THEN BUILD INTO THE
WESTERN ATLANTIC FOR THE REST OF THE WEEK. IT WILL STOP THE
PROGRESSION OF ANOTHER COLD FRONT AS IT TRIES TO EXIT THE SAINT
LAWRENCE VALLEY ON SATURDAY. A THIRD AND SLIGHTLY STRONGER COLD
FRONT IS FORECAST TO MOVE THROUGH THE GREAT LAKES ON SUNDAY AND
SLOWLY MOVE THROUGH OUR FORECAST AREA ON MONDAY BEFORE STALLING
SOUTH OF THE REGION ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE LINE OF THUNDERSTORMS APPROACHING FROM SOUTH CENTRAL
PENNSYLVANIA IS FALLING APART...AS IT OUTRUNS ITS INSTABILITY
SOURCE. A FEW GUSTS TO 40 MPH ARE POSSIBLE WITH THE STORMS AS THEY
REACH THE LEHIGH VALLEY AND POSSIBLE SOUTHEAST PENNSYLVANIA.
HOWEVER...THE OVERALL WEAKENING TREND SHOULD CONTINUE AS THE LOW
LEVEL STABILIZE AHEAD OF THE AREA OF SHOWERS AND THUNDERSTORMS.
THE LATEST HRRR TRIES TO KEEP THIS LINE INTACT AS IT APPROACHES
PHILADELPHIA AFTER 0300 UTC. THIS IS LOOK MORE LIKELY NOW BASED ON
THE TREND OF THE AREAL MOVEMENT. THE UPTICK IN ACTIVITY WAS
INCLUDED IN THE MOST RECENT FORECAST UPDATE.
A BRIEF LULL IS EXPECTED BEFORE MORE SHOWERS APPROACH FROM THE
WEST DURING THE LATE OVERNIGHT HOURS AS A FRONTAL BOUNDARY PUSHES
EAST. TEMPERATURES ARE EXPECTED TO BOTTOM OUT IN THE LOW 60S NORTH
AND IN THE UPPER 60S SOUTH. WITH DEW POINT TEMPERATURES WITHIN A
DEGREE OR TWO OF THESE LOWS...SOME PATCHY FOG IS POSSIBLE TOWARD
MORNING. LIGHT AND VARIABLE WINDS DURING THE OVERNIGHT HOURS ARE
EXPECTED TO BECOME SOUTHERLY TOWARD MORNING.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
SHOWERS...AND POSSIBLY A THUNDERSTORM OR TWO...ARE EXPECTED TO
APPROACH OUR WESTERN COUNTIES DURING THE LATE OVERNIGHT HOURS...THEN
OVERSPREAD THE REST OF OUR FORECAST AREA AS THE DAY WEARS ON. GIVEN
THE AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...SOME HEAVY
DOWNPOURS ARE POSSIBLE ON WEDNESDAY. THESE DOWNPOURS ARE EXPECTED TO
BE ISOLATED...BUT WHERE THEY DO OCCUR...THEY COULD PRODUCE A
SIGNIFICANT AMOUNT OF RAIN IN A SHORT PERIOD OF TIME. TEMPERATURES
ARE EXPECTED TO MAX OUT IN THE MID 80S MOST PLACES GIVEN A GOOD
CLOUD COVER AND RAIN CONDITIONS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
NO BIG CHANGES TO THE LONG TERM VS YESTERDAY AS THE TROFINESS IN
THE EASTERN CONUS WILL BE REPLACED BY A MORE ZONAL FLOW. THIS WILL
BRING THE RETURN OF A HOTTER AND MORE HUMID AIR MASS INTO MONDAY
WITH THE POSSIBILITY OF SOME DRYING AND LESSER POSSIBILITY OF
"COOLING" ON TUESDAY.
WHILE THE GFS INITIALIZATION LOOKED BETTER AT 500MB, ITS PERFECTLY
SPHERICAL GRID SCALE PRODUCED LOW PRESSURE SYSTEMS IN THE SHORT TERM
HAS MADE US DISCARD IT FOR THE LONG TERM. THE PASSING OF A STRONGER
LOW PRESSURE SYSTEM FASTER ON THURSDAY IS ILLOGICAL. STRONGER
SHOULD BE SLOWER AND STRONGER SOLUTIONS SHOULD NOT OCCUR AS TROFS
ARE SHEARING. OUR SOLUTION IN THE NEARER END OF THE SHORT TERM
WAS TOWARD A WRF-NMMB AND ECMWF COMPROMISE AND AN ECMWF-HPC
COMPROMISE IN THE REST OF THE LONG TERM. THE GFS HAS NOT BEEN
ALONE WITH THESE LOWS COMING OFF THE SE COAST, DP/DTING SOME
CANADIAN AND WRF-NMMB SOLUTIONS HAS SHOWN LOW NUMBER ONE WAS
OVERFORECAST IN STRENGTH ALSO.
THE IMPULSE ASSOCIATED WITH THE DISSIPATING COLD FRONT WILL CONTINUE
TO MOVE THROUGH OUR CWA ON WEDNESDAY EVENING AND WE MAINTAIN
RELATIVELY HIGH POPS FOR THE START OF THE OVERNIGHT AND MAINLY IN
THE OFFSHORE WATERS LATE. STAT GUIDANCE LOOKS REASONABLE AND WAS
FOLLOWED.
ON THURSDAY THE FASTER AND STRONGER GFS AND STRONGER CAN GGEM WERE
DISCOUNTED AS LIKELY BEING AFFECTED BY GRIDSCALE FEEDBACK EFFECTS.
OUR SOLUTION IS CLOSEST TO THE WRF-NMMB TRACK AND STRENGTH. THIS
WOULD ALLOW ENOUGH SEPARATION BETWEEN SYSTEMS FOR SCATTERED
THUNDERSTORMS TO DEVELOP DURING THE DAY. HIGHEST POPS WERE PLACED IN
THE DELAWARE VALLEY WHERE CONSENSUS HIEST FCST CAPES EXIST. BECAUSE
OF THE STRONG SYSTEM, GFS MOS MAX TEMPS ARE LOWER ON THU. WE ARE
OPTING FOR A WARMER AIR MASS AND ARE CLOSER TO NAM MOS.
PRECIPITATION SHOULD BE DIURNALLY DRIVEN AND AS WE APPROACH THE 72HR
ITS HARD TO ACCEPT THAT THE WRF-NMMB IS GOING TO VERIFY ITS TIMING
AND PLACEMENT WITH THE OVERNIGHT SHORTWAVE NORTH. SO POPS WERE
DROPPED QUICKLY THURSDAY EVENING. MIN TEMPS WERE A STAT GUIDANCE
COMPROMISE.
FRIDAY MIGHT STILL BE THE "DRY POPLESS DAY". BUT FOR NOW, MODEL
FORECAST SOUNDINGS DO NOT SHOW A STRONG ENOUGH CAP. POPS WERE PLACED
NORTHWEST WHERE HIEST FCST INSTABILITY WAS SHOWN BY THE MAJORITY OF
MODELS. HERE WE DO NOT THINK THAT THE WRF-NMMB SOLUTION OF
BRINGING THE AXIS OF INSTABILITY CAN BUCK THE ZONAL FLOW AND GET
INTO THE SOUTHERN PART OF OUR CWA. BY THIS TIME PERIOD ITS LIKELY
SHOWING ITS HOT BIAS AND OUR MAX TEMPS ARE CLOSER TO GFS MOS. BTW
THE 00Z MEX MOS GUIDANCE WAS AMONG THE HOTTEST OF ITS ENSEMBLE
MEMBERS. FCST DEW POINTS KEEP AFTERNOON HEAT INDICES SHORT OF HEAT
HEADLINE CRITERIA IN URBAN AREAS.
NO BIG CHANGES TO WEEKEND THINKING WITH SUNDAY BEING THE MORE
LIKELIER DAY TO HAVE TSTMS AROUND. NEXT ATTEMPTED COLD FRONT SHOULD
STOP SHORT OF OUR CWA ON SATURDAY, BUT IMPULSES FROM IT SHOULD
TRIGGER AT LEAST SOME WIDELY SCATTERED TSTMS. A BETTER CHANCE ON
SUNDAY AS THE FRONT APPROACHES AND IN LIKELIHOOD A LEE SIDE TROF
FORMS. MAX TEMPS ARE KEPT AS STATUS QUO VS DROPPING THEM ON THE
WEEKEND BASED ON FCST 850MB AND 925MB TEMPS AND NOT COUNTING ON
EXCESS CLOUDINESS TO KEEP TEMPS DOWN. WITH HIGHER DEW POINTS, WE
MIGHT MAKE HEAT HEADLINE CRITERIA ON THE WEEKEND IN THE MORE
URBANIZED LOCALES AND WE WILL CONTINUE MENTION IN THE HWO.
NOT AS SURE FOR MONDAY,
THE FRONT IS EXPECTED TO TRUNDLE THROUGH OUR FORECAST AREA ON
MONDAY. THE MODEL TIMING IS NOT THAT DIFFERENT AND THE 00Z ECMWF
ENSEMBLE MEAN WAS CLOSE TO THE MODEL`S DETERMINISTIC SOLUTION. THUS
NOT AS CONFIDENT ABOUT THE 90S OR HEAT HEADLINES ON MONDAY AS THERE
SHOULD BE MORE CLOUDS AROUND AND HAVE PLACED HIEST POPS EAST BASED
ON THE ENSEMBLE FRONTAL POSN AT 12Z MON.
WHILE THIS FRONT MAY BE `STRONGER", ITS ONLY BECAUSE THE PREVIOUS
TWO WERE LEFT IN THE METEOROLOGICAL GUTTER. SO ON TUESDAY ITS BEST
IMPACT MAY BE TO LOWER DEW POINTS SOMEWHAT WITH NOT A BIG DROP IN
TEMPS FORECAST. WE WILL START TUESDAY AS A DRY DAY AND SEE WHAT
TOMORROW BRINGS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
NEAR TERM MODEL SUGGEST THAT THE SHOWERS COULD AFFECT THE KPHL
METRO AIRPORTS AND KILG THROUGH 0600 UTC. IT IS POSSIBLE THAT THE
KPHL METRO AIRPORTS COULD SEE A BRIEF PERIOD OF MVFR CONDITIONS
WITH THE SHRINKING AREA OF SHOWERS AND THUNDERSTORMS. THE TERMINAL
FORECASTS THERE WILL BE UPDATED AS THE AREA GETS CLOSER.
AFTER THIS...THE FORECAST SHOULD BE DRY. THE EAST SOUTHEAST FLOW
COULD RESULT IN A PERIOD OF MVFR CEILINGS AT KRDG...KABE AND KTTN.
FURTHER SOUTH AND EAST...THE CEILING FORECAST WAS MAINLY VFR...WITH
PATCHY FOG AT KMIV.
FOR WEDNESDAY...MAINLY VFR CONDITIONS ARE EXPECTED. AN ONGOING LINE
OF SHOWERS AND THUNDERSTORMS COULD BEGIN TO AFFECT KRDG AND KABE AS
EARLY AS 1400 UTC...AND THIS IS INCLUDED AS A VCSH REMARK AT THESE
LOCATIONS. ELSEWHERE...THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
WAS PUSHED BACK UNTIL 1700 UTC...AND INDICATED WITH A PROB30 REMARK.
WHILE THUNDERSTORMS COULD PRODUCE LOCAL MVFR/IFR CONDITIONS...IT IS
STILL TO EARLY TO INCLUDE THIS IN THE FORECAST. THE THREAT FOR
SHOWERS AND THUNDERSTORMS SHOULD DIMINISH AFTER 0100 UTC THURSDAY.
OUTLOOK...
WEDNESDAY NIGHT...PRIMARILY VFR, EXCEPT LOCALLY IFR IN SCATTERED
HEAVY SHOWERS AND STRONG THUNDERSTORMS. ALSO LOCALLY MVFR TO IFR
IN FOG LATE WED NIGHT.
THURSDAY THROUGH FRIDAY NIGHT...VFR, ISOLATED MVFR CONDITIONS IN
EARLY MORNING FOG AND MORE ISOLATED (VS WEDNESDAY) SHOWERS AND
THUNDERSTORMS.
SATURDAY...PRIMARILY VFR. ISOLATED AFTN/EVENING TSTM. SOME
EARLY MORNING FOG OUTLYING AIRPORTS.
SUNDAY...PRIMARILY VFR. SCATTERED AFTN/EVENING TSTM SHOULD HAVE
MORE OF A MVFR AND OPERATIONAL IMPACT. SOME EARLY MORNING FOG
OUTLYING AIRPORTS.
&&
.MARINE...
THE FORECAST WAS UPDATED TO BEEF UP WINDS OVER THE DELAWARE BAY.
BOTH BRND1 AND SJSN4 ARE GUSTING TO NEAR 20 KNOTS. THE INCREASE IN
WIND SPEED APPEARS TO BE DUE TO THE WIND DIRECTION (FUNNELING ON
THE DAY) AND THE DIURNAL WIND MAXIMUM (WHICH SHOULD START TO BACK
OFF SOON). WINDS SHOULD DROP OFF FAIRLY QUICKLY LATER THIS EVENING.
A BRIEF LULL IS EXPECTED OVER THE FORECAST WATERS LATER TONIGHT
AS LOW PRESSURE OFF THE COAST MOVES NORTHEAST. A GENERAL EASTERLY
FLOW WILL SHIFT TO A MORE SOUTHERLY FLOW LATE TONIGHT AND CONTINUE
THROUGH WEDNESDAY. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A
ADVANCING FRONT WILL MOVE IN FROM THE WEST WEDNESDAY AFTERNOON AND
CONTINUE INTO WEDNESDAY NIGHT. SOME OF THESE THUNDERSTORMS COULD
PRODUCE LOCALLY HAZARDOUS MARINE CONDITIONS...BUT RIGHT NOW SUB-
SCA CONDITIONS ARE EXPECTED ON THE LARGE SCALE.
OUTLOOK...
AS PER PMDHMD AND OPC MIMATN DISCUSSION, WE ARE NOT GOING TO BE
FOLLOWING THE GFS SOLUTION. THUS WINDS AND SEAS WITH THE NEXT
OFFSHORE LOW ARE EXPECTED TO REMAIN BELOW SCA CRITERIA IN OUR
COASTAL WATERS UNTIL THE LOW PASSES TO OUR EAST AROUND THURSDAY.
BEYOND THAT, A GENERAL SOUTHERLY FLOW IS EXPECTED TO PERSIST INTO
SUNDAY. ITS POSSIBLE BY SUNDAY OR BEYOND DETERMINISTIC FORECAST
MONDAY, THE GRADIENT OR PERSISTENCE OF THE SOUTHERLY FLOW MIGHT BE
ENOUGH FOR SMALL CRAFT ADVISORY CRITERIA TO BE MET. IT MAY BE MORE
FOR SEAS THAN WINDS. REGARDLESS CONFIDENCE ABOUT REMAINING BELOW
SMALL CRAFT ADVISORY CRITERIA LOWERS AS THE WEEKEND PROGRESSES.
&&
.HYDROLOGY...
HEAVY DOWNPOURS ASSOCIATED WITH THUNDERSTORMS...ESPECIALLY WEDNESDAY
AFTERNOON...COULD PRODUCE RAPID RUNOFF IN SOME AREAS. THIS SCENARIO
BRINGS WITH IT THE THREAT OF HIGHLY LOCALIZED FLOODING...ESPECIALLY
IN URBAN SETTINGS. RIGHT NOW THIS THREAT DOESN`T APPEAR TO BE
WIDESPREAD ENOUGH TO WARRANT A FLASH FLOOD WATCH...BUT GIVEN THE
AMOUNT OF MOISTURE AVAILABLE IN THE ATMOSPHERE...CAN`T RULE OUT ONE
OR TWO ISOLATED PROBLEMS.
&&
.TIDES/COASTAL FLOODING...
COASTAL FLOODING ADVISORY FOR THE UPPER DELAWARE BAY WAS LOWERWS
AT 1230 AM.
ANOTHER ROUND OF MINOR TIDAL FLOODING MAY OCCUR WEDNESDAY EVENING
DUE TO A PERSISTENT SOUTHERLY FLOW AND FULL MOON.
&&
.RIP CURRENTS...
MODERATE RISK INTO WEDNESDAY WITH A CONTINUED 2-3 FT SWELL AND
HIGHER THAN NORMAL ASTRONOMICAL TIDES ASSOCIATED WITH THE UPCOMING
FULL MOON.
&&
.CLIMATE...
TOP FIVE WARMEST JULYS ON RECORD IN PARTS OF OUR AREA.
IN TERMS OF 90 DEGREE DAYS FOR THE MONTH OF JULY.
AT PHILADELPHIA 21 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
HIGHER OCCURRED THROUGH THE 29TH. THIS TIES THE RECORD FOR
THE MOST NUMBER OF 90 DEGREES DAYS ALL TIME WITH 1952, 1988, 1995
AND 2011.
AT ALLENTOWN 15 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR HIGHER
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1983, 2010 AND
2011. GREATEST IS 20 DAYS IN 1999, 1966 AND 1955.
AT WILMINGTON 17 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SIXTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 1952. GREATEST
IS 22 DAYS IN 1894.
AT ATLANTIC CITY 14 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR
MORE OCCURRED THROUGH THE 29TH. THIS IS FIFTH ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY TIED WITH 2010. GREATEST IS
21 DAYS IN 1983.
AT READING 19 DAYS WITH A HIGH TEMPERATURE OF 90 DEGREES OR MORE
OCCURRED THROUGH THE 29TH. THIS IS SECOND ALL TIME IN TERMS OF DAYS
REACHING 90 DEGREES FOR THE MONTH OF JULY. GREATEST IS 20 DAYS
SET IN 2011, 2010, 1999 AND 1955.
IN TERMS OF WARMEST AVERAGE TEMPERATURE RECORDED FOR THE MONTH OF
JULY.
AT PHILADELPHIA THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 81.9. WE ARE PROJECTING 81.7 FOR THE MONTH. THIS IS THE THE
THIRD WARMEST JULY ON RECORD BEHIND 2011 82.4 AND 1994 82.1 AND
EQUALING THE 81.7 IN 2010.
AT WILMINGTON THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 80.4. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2011 AND
1955.
AT ATLANTIC CITY THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 78.7. THIS IS THE THIRD WARMEST JULY ON RECORD BEHIND 2010
AND 2011.
AT ALLENTOWN THE AVERAGE TEMPERATURE FOR THE MONTH THROUGH THE 30TH
WAS 77.6 AND IS THE SEVENTH WARMEST JULY ON RECORD.
DATA SINCE 6/28 THROUGH 7/30...33 DAYS.
RDG ONLY 2 DAYS BELOW NORMAL
PHL/ABE/GED ONLY 3 DAYS BELOW NORMAL
TTN 5 DAYS BELOW NORMAL
MPO 5 DAYS BELOW NORMAL
ILG 6 DAYS BELOW NORMAL
ACY 10 DAYS BELOW NORMAL
90 OR HIGHER FOR THE SEASON
SO FAR TOTAL
NORMAL THIS YR LAST YR POR
ABE 17 24 21 1922
ACY 22 31
GED 29 40
ILG 27 27
PHL 21 30 33 1874
RDG 30 30
TTN 25 26
MPO 3 4
THE NORMAL AND PERIOD OF RECORD /POR/ IS LISTED FOR ONLY TWO CLIMATE
SITES WHERE THE DATASET IS EASILY AVAILABLE AND COMPLETE.
WITH RESPECT TO OCCURRENCES OF 95 OR GREATER PHL CLIMATOLOGICALLY
AVG`S 4/YR SO FAR THIS YR 12 LAST YRS TOTAL 11.
STATISTICALLY FOR PHL AS EVALUATED BY MARK DELISI...THE NUMBER OF 95
OR WARMER DAYS THIS YEAR IS UNUSUAL.
FOR OUR FORECAST AREA...
PCPN FOR THE MONTH SO FAR NOW GENERALLY WITHIN 75 PCT OF NORMAL.
TEMP FOR THE MONTH SO FAR NOW GENERALLY 2.5 TO 5F ABOVE NORMAL.
&&
.EQUIPMENT...
KDOX RADAR IS EXPECTED TO BE OFFLINE FOR SEVERAL DAYS DUE TO A
PEDESTAL DYNAMIC FAULT. TECHNICIANS ARE WORKING ON THE PROBLEM.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GIGI
NEAR TERM...MIKETTA
SHORT TERM...MIKETTA
LONG TERM...GIGI
AVIATION...DRAG/GIGI/HAYES
MARINE...GIGI/HAYES/MIKETTA
HYDROLOGY...
TIDES/COASTAL FLOODING...
RIP CURRENTS...
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1249 AM MDT WED AUG 1 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 226 PM MDT TUE JUL 31 2012
15Z WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED LARGE
ANTICYCLONIC CIRCULATION ALOFT IN PLACE ACROSS THE SOUTHERN PLAINS
WITH CWA ON NORTHERN PERIPHERY OF CIRCULATION...WITH ANOTHER SHORT
WAVE TROUGH NOTED UPSTREAM ALONG THE UTAH AND COLORADO BORDER. 12Z
RAOBS INDICATED LITTLE CHANGE OVER THE PAST 24 HOURS ASIDE FROM SOME
LOW LEVEL DRYING AT LBF...WITH STEEP LAPSE RATES STILL OBSERVED
MAINLY BETWEEN H7 AND H6 AT BOTH DDC AND DNR.
MAIN SHORT TERM ISSUE WILL BE PRECIPITATION CHANCES LATE THIS
AFTERNOON AND EVENING.
TONIGHT...OVERALL PATTERN HAS CHANGED LITTLE FROM YESTERDAY WITH
LARGE SCALE RIDGE REMAINING TO THE SOUTH OF THE AREA AND SHORT WAVE
TROUGH MOVING OVER THE TOP OF THE RIDGE TONIGHT. OVERALL INSTABILITY
AND PW PROFILES SIMILAR AS WELL...WITH ONLY LOW LEVEL SHEAR BEING
NOTICEABLY WEAKER THAN YESTERDAY. WITH CU FIELDS DEVELOPING OVER THE
HIGHER TERRAIN AND NEAR MESOLOW NOTED OVER YUMA COUNTY...FAIRLY
LARGE LCLS IN PLACE FAVORING STRONG COLD POOLS AND MCS VECTORS
FAVORING EASTWARD MOTION INTO STRONGER INSTABILITY ACROSS THE CWA
THINK CHANCES FOR ANOTHER ROUND OF PRECIPITATION FAIRLY GOOD
ACROSS MUCH OF THE CWA...BUT UNTIL SOME ECHOES BEGIN TO DEVELOP
DOWNSTREAM AM HESITANT TO GO MUCH ABOVE THE 40-50% RANGE FOR POPS
ATTM. BEST TIMING FOR PRECIP LOOKS TO BE IN THE 00-04Z RANGE...BUT
WITH LINGERING WAA THROUGH THE NIGHT THINK AT LEAST A FEW WEAK
SHOWERS WILL CONTINUE THROUGH THE EARLY MORNING HOURS.
TEMPERATURES SHOULD BE FAIRLY SIMILAR TO WHAT OCCURRED LAST NIGHT
WITH WET BULB TEMPS WITH THUNDERSTORMS LIKELY BRINGING TEMPS DOWN
INTO THE 60S AS STORMS PASS RESULTING IN AT LEAST FEW LOCATIONS
SEEING LOW TEMPS OCCURRING EARLIER THAN NORMAL. WITH HIGH
PRECIPITABLE WATERS AND DEEP WARM CLOUD LAYER/FREEZING LEVEL
AROUND 17 KFT MSL...HEAVY RAIN WILL BE A THREAT BUT THINK OVERALL
MCS MOTION WILL BE FAST ENOUGH TO LIMIT ANY WIDESPREAD FLASH FLOOD
THREAT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 1245 AM MDT WED AUG 1 2012
STRONG SYSTEM MOVING ACROSS THE NORTHERN PLAINS ON SATURDAY WILL
PUSH A SURFACE COLD FRONT WELL SOUTH OF THE FORECAST AREA.
TEMPERATURES ON SATURDAY WILL BE NEAR NORMAL...BUT PRECIPITATION
CHANCES SHOULD STAY SOUTH NEAR THE FRONT. RIDGE WILL REBUILD LATE
IN THE WEEKEND AND EARLY NEXT WEEK WITH TEMPERATURES BACK TO ABOVE
NORMAL. PRECIPITATION CHANCES COULD RETURN AS EARLY AS TUESDAY
WITH THE RIDGE BREAKING DOWN AND SHORTWAVE TROUGHS MOVING OUT OF
COLORADO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1122 PM MDT TUE JUL 31 2012
REMAINING SHOWERS AND THUNDERSTORMS ACROSS THE REGION SHOULD BE
DISSIPATING THROUGH THE OVERNIGHT HOURS BEFORE THEY HAVE AN
OPPORTUNITY TO MOVE OVER THE TAF SITES. HAVE NOT INCLUDED ANY
SHOWERS IN THE TAFS UNTIL WEDNESDAY EVENING BETWEEN 00Z-06Z.
THERE IS A POSSIBILITY CONDITIONS WILL DETERIORATE BELOW VFR IF A
STRONGER STORM MOVES DIRECTLY OVER ONE OF THE OBSERVATION
SITES...OTHERWISE HAVE KEPT CONDITIONS VFR THROUGH THE PERIOD AT
BOTH KMCK AND KGLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...024
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1148 PM MDT TUE JUL 31 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 226 PM MDT TUE JUL 31 2012
15Z WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED LARGE
ANTICYCLONIC CIRCULATION ALOFT IN PLACE ACROSS THE SOUTHERN PLAINS
WITH CWA ON NORTHERN PERIPHERY OF CIRCULATION...WITH ANOTHER SHORT
WAVE TROUGH NOTED UPSTREAM ALONG THE UTAH AND COLORADO BORDER. 12Z
RAOBS INDICATED LITTLE CHANGE OVER THE PAST 24 HOURS ASIDE FROM SOME
LOW LEVEL DRYING AT LBF...WITH STEEP LAPSE RATES STILL OBSERVED
MAINLY BETWEEN H7 AND H6 AT BOTH DDC AND DNR.
MAIN SHORT TERM ISSUE WILL BE PRECIPITATION CHANCES LATE THIS
AFTERNOON AND EVENING.
TONIGHT...OVERALL PATTERN HAS CHANGED LITTLE FROM YESTERDAY WITH
LARGE SCALE RIDGE REMAINING TO THE SOUTH OF THE AREA AND SHORT WAVE
TROUGH MOVING OVER THE TOP OF THE RIDGE TONIGHT. OVERALL INSTABILITY
AND PW PROFILES SIMILAR AS WELL...WITH ONLY LOW LEVEL SHEAR BEING
NOTICEABLY WEAKER THAN YESTERDAY. WITH CU FIELDS DEVELOPING OVER THE
HIGHER TERRAIN AND NEAR MESOLOW NOTED OVER YUMA COUNTY...FAIRLY
LARGE LCLS IN PLACE FAVORING STRONG COLD POOLS AND MCS VECTORS
FAVORING EASTWARD MOTION INTO STRONGER INSTABILITY ACROSS THE CWA
THINK CHANCES FOR ANOTHER ROUND OF PRECIPITATION FAIRLY GOOD
ACROSS MUCH OF THE CWA...BUT UNTIL SOME ECHOES BEGIN TO DEVELOP
DOWNSTREAM AM HESITANT TO GO MUCH ABOVE THE 40-50% RANGE FOR POPS
ATTM. BEST TIMING FOR PRECIP LOOKS TO BE IN THE 00-04Z RANGE...BUT
WITH LINGERING WAA THROUGH THE NIGHT THINK AT LEAST A FEW WEAK
SHOWERS WILL CONTINUE THROUGH THE EARLY MORNING HOURS.
TEMPERATURES SHOULD BE FAIRLY SIMILAR TO WHAT OCCURRED LAST NIGHT
WITH WET BULB TEMPS WITH THUNDERSTORMS LIKELY BRINGING TEMPS DOWN
INTO THE 60S AS STORMS PASS RESULTING IN AT LEAST FEW LOCATIONS
SEEING LOW TEMPS OCCURRING EARLIER THAN NORMAL. WITH HIGH
PRECIPITABLE WATERS AND DEEP WARM CLOUD LAYER/FREEZING LEVEL
AROUND 17 KFT MSL...HEAVY RAIN WILL BE A THREAT BUT THINK OVERALL
MCS MOTION WILL BE FAST ENOUGH TO LIMIT ANY WIDESPREAD FLASH FLOOD
THREAT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 226 PM MDT TUE JUL 31 2012
H5 RIDGE WILL BEGIN TO FLATTEN WITH WESTERLY ZONAL FLOW
DEVELOPING OVER THE NORTHERN PLAINS. THIS WILL ALLOW FOR A SERIES OF
STRONGER SHORTWAVE TROUGHS TO MOVE THROUGH THE NORTHERN PLAINS...AND
ASSOCIATED COLD FRONTS TO DROP SOUTH TOWARDS THE CWA.
THE FIRST OF THESE FRONT WILL ARRIVE LATE WEDNESDAY EVENING.
INSTABILITY AND MOISTURE WILL REMAIN IN PLACE THROUGH THE DAY
WEDNESDAY...WITH INITIATION DURING THE AFTERNOON FOLLOWING SIMILAR
PATTERN AS THE LAST FEW NIGHTS IN THE WEST/NORTHWEST. ISOLATED
ACTIVITY SHOULD INCREASE IN COVERAGE DURING THE EVENING HOURS AS
THUNDERSTORMS BECOME MORE ORGANIZED UNDER WEAK FLOW. DIFFERENCE WILL
BE WITH LARGE SCALE ASSOCIATED WITH COLD FRONT IN THE EVENING
HOURS...WHICH COULD HELP WITH COVERAGE/STRENGTH OF THUNDERSTORMS.
SOUNDINGS APPEAR TO BE DRIER THAN THE LAST FEW DAYS...HOWEVER PWAT
VALUES OVER 1 INCH ARE STILL BEING ADVERTISED. DEPENDING ON THE
TIMING OF THE FRONT POSITION OF THE BEST THUNDERSTORM COVERAGE COULD
BE PUSHED TO THE SOUTH AND EAST QUICKER THAN CURRENTLY
ADVERTISED...SO I WAS NOT CONFIDENT ENOUGH TO GO HIGHER THAN 40 POPS
DURING THE EVENING.
WEAK SHORTWAVE TROUGHS WILL CONTINUE TO MOVE NORTH OF THE CWA ON
THURSDAY...HOWEVER WITH POST FRONTAL AIRMASS IN PLACE I HAVE
QUESTIONS TO HOW MUCH SURFACE BASE AND MIXED LAYER CAPE WILL
BE AROUND TO INITIATE THUNDERSTORMS. FOR NOW I HAVE KEPT POPS
LIMITED TO 20 RANGE THU/THU NIGHT. BETTER CHANCES RETURN FRIDAY
NIGHT WHEN A STRONGER TROUGH MOVES THROUGH THE NORTHERN PLAINS AND
ANOTHER COLD FRONT DROPS SOUTH ACROSS THE CWA. HAVE INCREASED POPS
TO CHANCE CATEGORY. GUIDANCE CONTINUES TO SHOW CHANCES LINGERING
THROUGH SATURDAY NIGHT AS ADDITIONAL WEAKER SHORTWAVES MOVE
THROUGH THE AREA ON NORTHERN EXTENT OF RIDGE. CONFIDENCE IS LOWER
ON THIS ACTIVITY...SO I LIMITED IT TO SLIGHT CHANCE.
TEMPERATURES ON WEDNESDAY AND THURSDAY SHOULD BE AROUND OR ABOVE
100F WITH GOOD WAA AHEAD OF APPROACHING COLD FRONTS. BEHIND THE
FRONT ON THURSDAY AFTERNOON TEMPS WILL BE IN THE MID TO UPPER
90S...WITH NEAR NORMAL TEMPERATURES ON SATURDAY IN THE UPPER 80S/LOW
90S. THE H5 RIDGE WILL BEGIN TO BUILD NORTH AGAIN AND STRENGTHEN
SUNDAY INTO EARLY NEXT WEEK AND BRING US BACK TO 100 DEGREE
TEMPERATURES AND A DRIER PATTERN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1122 PM MDT TUE JUL 31 2012
REMAINING SHOWERS AND THUNDERSTORMS ACROSS THE REGION SHOULD BE
DISSIPATING THROUGH THE OVERNIGHT HOURS BEFORE THEY HAVE AN
OPPORTUNITY TO MOVE OVER THE TAF SITES. HAVE NOT INCLUDED ANY
SHOWERS IN THE TAFS UNTIL WEDNESDAY EVENING BETWEEN 00Z-06Z.
THERE IS A POSSIBILITY CONDITIONS WILL DETERIORATE BELOW VFR IF A
STRONGER STORM MOVES DIRECTLY OVER ONE OF THE OBSERVATION
SITES...OTHERWISE HAVE KEPT CONDITIONS VFR THROUGH THE PERIOD AT
BOTH KMCK AND KGLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...DR
AVIATION...LOCKHART
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
355 AM EDT WED AUG 1 2012
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 335 AM EDT WED AUG 1 2012
06Z SFC ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE LAYING ACROSS THE
NORTHWEST PORTION OF EASTERN KENTUCKY...RELATED TO A MINOR COLD FRONT
THAT IS PASSING THROUGH THE AREA EARLY THIS MORNING. THIS HAS JUST
RECENTLY HELPED TO TRIGGER A FEW CELLS OF CONVECTION IN THE WESTERN
PARTS OF THE CUMBERLAND VALLEY...DRIFTING SOUTHEAST INTO THE
SOUTHERN INTERSTATE 75 CORRIDOR. ON SATELLITE...THE CLOUDS HAVE
INCREASED DURING THE PAST COUPLE OF HOURS IN RESPONSE TO THE
BOUNDARY AND SOME ENERGY PASSING THROUGH AT MID LEVELS. THE CLOUDS
WILL HELP TO LIMIT ANY FURTHER DROP IN TEMPERATURES THROUGH THE REST
OF THE NIGHT. AS IT STANDS...A MINOR RIDGE TO VALLEY TEMPERATURE
SPLIT ON THE ORDER OF ABOUT 5 DEGREES EXISTS OUT THERE...MAINLY IN
THE NORTHEAST AS OF 3 AM EDT. LOW DEWPOINT DEPRESSIONS ARE ALSO
FOUND IN THE VALLEYS AND ANY PLACE THAT MANAGE TO STAY MOSTLY CLEAR
CAN EXPECT PATCHY FOG IN THE VALLEYS TOWARD DAWN...POSSIBLY DENSE IN
LOCATIONS CLOSER TO THE VIRGINIA BORDER THAT SAW SOME DECENT RAINS ON
TUESDAY AFTERNOON.
THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT WITH THE MAIN FEATURES
AFFECTING THE SHORT TERM FORECAST. THEY AGREE THAT STRONG RIDGING
WILL REMAIN PARKED OFF TO THE SOUTHWEST OF THE AREA...IN NORTHERN
TEXAS...AND THAT THE EASTERN THIRD OF THE NATION WILL BE IN BROAD
TROUGHING...DOWNSTREAM OF THE RIDGE. LOCALLY...EAST KENTUCKY WILL BE
UNDER THE INFLUENCE OF NORTHWEST FLOW WITH A COUPLE OF WEAK
SHORTWAVES PASSING OVERHEAD INTO THURSDAY. ONE OF THESE WAVES IS
PASSING THIS MORNING AND IS PARTIALLY RESPONSIBLE FOR THE CURRENT
CONVECTION IMPACTING OUR WESTERNMOST COUNTIES. THE NEXT WILL COME
THROUGH THIS EVENING AND SHOULD BRING AN UPTICK IN CONVECTIVE
POTENTIAL TO THE AREA...THOUGH ITS BEST INFLUENCE WILL LIKELY BE FELT
FURTHER TO THE EAST. TOWARD THE END OF THE PERIOD...THE PATTERN
BECOMES MORE ZONAL AS THE EASTERN TROUGH STARTS TO FLATTEN OUT AND
THE WESTERN RIDGE SHIFTS SOUTH. GIVEN THE MODEL SIMILARITIES HAVE
FOLLOWED A BLENDED SOLUTION WITH A STRONG LEAN TOWARD THE HIGHER
RESOLUTION NAM12 OUTSIDE OF THE NEXT 12 HOURS...WHEN THE HRRR IS
PREFERRED.
SENSIBLE WEATHER WILL FEATURE THE CURRENT CONVECTION WINDING DOWN
LATER THIS MORNING IN THE SOUTH WITH BUILDING INSTABILITY POSSIBLY
HELPING TO KICK OFF SOME MORE IN THE FAR EAST LATER IN THE
AFTERNOON...SIMILAR TO WHAT OCCURRED ON TUESDAY. THIS SHOULD BE THE
LAST THREAT OF CONVECTION THROUGH THE SHORT TERM...THOUGH...AS
LIMITED UPPER LEVEL SUPPORT AND WEAK SFC HIGH PRESSURE WILL LIKELY
SUPPRESS CONVECTION AFTER 00Z TONIGHT. AS SUCH...WE CAN EXPECT
ANOTHER WARM AND HUMID COUPLE OF DAYS WITH HEAT INDICES MAXING OUT
BETWEEN 95 AND 100 DEGREES EACH AFTERNOON. WILL MENTION THIS IN THE
FORTHCOMING HWO. AT NIGHT...PATCHY VALLEY FOG WILL BE THE NORM WITH A
SMALL RIDGE TO VALLEY TEMPERATURE SPLIT EACH NIGHT AS TEMPERATURES
AND DEWPOINTS KEEP A MUGGINESS IN THE AIR...AND PATCHY FOG IN THE
VALLEYS TOWARD DAWN.
FOLLOWED A BLEND OF PERSISTENCE...EXISTING GRIDS...AND THE LATEST
MET GUIDANCE FOR TEMPERATURES THROUGH THE SHORT TERM. AS FOR POPS...
ENDED UP JUST ON THE HIGH SIDE OF GUIDANCE TODAY AND IN LINE WITH IT
FOR TONIGHT AND THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 355 AM EDT WED AUG 1 2012
OVERALL...THE LONG TERM LOOKS TO BE UNSETTLED WITH QUITE A BIT OF
RAIN POTENTIAL OVER THE PERIOD. A BERMUDA HIGH IS EXPECTED TO BE
STRENGTHENING OVER THE ERN U.S. WHILE AN AREA OF LOW PRESSURE GAINS
MOMENTUM OVER CANADIAN PRAIRIES BENEATH A RELATIVELY ZONAL FLOW
ALOFT OVER THE OHIO VALLEY TO START THE PERIOD. RETURN FLOW IS
EXPECTED TO BE UNDER WAY BY FRIDAY...USHERING AMPLE MOISTURE BACK
INTO THE REGION WITH PWATS PROGGED TO BE AROUND 2 INCHES FROM LATE
FRIDAY THROUGH SUNDAY AFTERNOON.
GUIDANCE CONTINUES TO POINT TOWARDS A COUPLE OF SHORT WAVES SKIRTING
THE AREA AROUND THE FRIDAY/SATURDAY TIME FRAME. THE LATEST GFS ALONG
WITH THE GEM ARE STILL ADVERTISING A RATHER POTENT WAVE REACHING THE
TN VALLEY ON FRIDAY IN CONJUNCTION WITH MODEST ISENTROPIC LIFT AT
H85 OVER ERN KY DURING THE AFTERNOON. STILL NOT CONFIDENT ENOUGH TO
GO HIGHER THAN CHANCE AT THIS POINT BUT ANOTHER ROUND OF OFFERINGS
WITH THE SAME SOLUTIONS SHOULD WARRANT A BUMP UP TO LIKELY POPS FOR
AT LEAST PART OF THE CWA ON FRIDAY. SATURDAY IS LOOKING SIMILAR TO
FRIDAY...THOUGH WITH LESS IN THE WAY OF SHORT WAVE TRIGGERS...BUT
ATTAINABLE FCST CONVECTIVE TEMPS IN THE LOWER 80S ALONG WITH ANY
REMNANT BOUNDARIES FROM FRIDAY MAY BE ENOUGH TO GET THINGS GOING
BEFORE OUTFLOW PROCESSES TAKE OVER.
FOCUS THEN SHIFTS TO AN ALBERTA CLIPPER SYSTEM MOVING THROUGH THE
UPPER MIDWEST AND INTO THE GREAT LAKES ON SUNDAY. THE MODELS
CONTINUE TO COME INTO BETTER ALIGNMENT WITH THE TIMING OF THE SYSTEM
OVERALL. FORCING ASSOCIATED WITH THE COLD FRONT LOOKS TO BEGIN
APPROACHING THE AREA ON SUNDAY WITH SHOWERS AND THUNDERSTORMS
OVERSPREADING THE AREA DURING THE AFTERNOON AND EVENING BEFORE UPPER
LEVEL SUPPORT ARRIVES SUNDAY NIGHT INTO MONDAY. MODELS STILL SUGGEST
THE FRONT STALLING OVER THE AREA ON MONDAY AND DESPITE WHAT SHOULD
BE DIMINISHING MOISTURE BY THAT POINT...WILL KEEP CHANCE POPS FOR
MONDAY TO ACCOUNT FOR MODELS TENDENCIES TO BE A LITTLE FAST IN
MOVING THINGS OUT TOO QUICKLY THIS FAR OUT.
GIVEN THE INCREASING AGREEMENT AMONG THE MODELS...STAYED FAIRLY
CLOSE TO THE CONSENSUS NUMBERS FOR TEMPS THROUGHOUT THE PERIOD. THIS
RESULTED IN HIGHS ON FRIDAY AND SATURDAY RUNNING ABOVE NORMAL
BEFORE SLIDING BACK TOWARDS CLIMO FROM SUNDAY ONWARD. AFTER A MODEST
RIDGE/VALLEY SPLIT THURSDAY NIGHT...LOWS LOOK TO REMAIN WITHIN REACH
OF NORMAL THROUGHOUT THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 215 AM EDT WED AUG 1 2012
CONVECTION IS POPPING UP TO THE NORTHWEST OF PART OF THE FORECAST
AREA IN RELATION TO AN APPROACHING SFC BOUNDARY AND SOME ENERGY
ALOFT. HAVE PUSHED UP THE TIME OF THE VCSH IN THE EXISTING TAFS FOR
EARLY THIS MORNING. WILL HAVE TO MONITOR FOR A POSSIBLE VCTS AND CB
ADDITION AS THIS SCENARIO UNFOLDS OVER THE NEXT COUPLE OF HOURS. DO
EXPECT THE ACTIVITY TO SETTLE BY MID MORNING AND HAVE DROPPED ANY
MENTION OF PCPN BY THAT TIME. OTHERWISE...VFR CONDITIONS WILL
DOMINATE THROUGH THE PERIOD. DO STILL EXPECT TO SEE SOME PATCHY DENSE
VALLEY FOG LATE TONIGHT AND EARLY THIS MORNING...ESPECIALLY OVER
AREAS IN THE FAR SOUTHEAST THAT SAW THE RAIN YESTERDAY AFTERNOON...
BUT THE MAIN TAF SITES SHOULD REMAIN CLEAR. OUTSIDE OF ANY STRAY
THUNDERSTORMS...THE WINDS WILL BE LIGHT AND VARIABLE THROUGH THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM....MB
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
215 AM EDT WED AUG 1 2012
.UPDATE...
ISSUED AT 205 AM EDT WED AUG 1 2012
DID A QUICK PRE-PACKAGE UPDATE TO NUDGE UP POPS IN THE WESTERN
CUMBERLAND VALLEY FOR A FEW HOURS WITH THE NOCTURNAL CONVECTION NOW
SPROUTING TO THE AREA/S NORTHWEST. ALSO TWEAKED SKY...T...AND TD
GRIDS TO REFLECT CURRENT OBS AND TRENDS. UPDATES HAVE BEEN SENT TO
NDFD AND THE WEB.
UPDATE ISSUED AT 1029 PM EDT TUE JUL 31 2012
THE SHOWER ES AND THUNDERSTORMS HAVE MOVED OUT OF KENTUCKY INTO
VIRGINIA. A COLD FRONT IS APPROACHING THE AREA FROM THE NORTHWEST. I
HAVE KEPT SOME ISOLATED SHOWERS AND THUNDERSTORMS IN THE FORECAST AS
THE FRONT MOVES INTO THE AREA. CURRENTLY...THE ONLY UPSTREAM SHOWERS
ARE ON A TRAJECTORY TO MISS EASTERN KENTUCKY. MOST OF THE MODELS ARE
DEVELOPING PRECIPITATION OVER THE AREA. THE HRRR IS HINTING THAT THE
SHOWERS MAY DEVELOP AS THE FRONT INTERSECTS SOME OF THE OLD OUTFLOW
BOUNDARIES THAT WERE ALL OVER THE PLACE THIS EVENING. ONE OF THE
OUTFLOWS DIED ON A LINE FROM JOHNSON TO PULASKI COUNTIES. WILL HAVE
TO KEEP AN EYE ON THINGS TO SEE IF ANYTHING DEVELOPS. THE AIR MASS IN
FAIRLY UNSTABLE THIS EVENING...HOWEVER THE NAM BUFR IS SHOWING A MID
LEVEL CAP DEVELOPING AFTER MIDNIGHT. THIS MAY KEEP ANY SHOWERS THAT
DEVELOP FROM GROWING INTO THUNDERSTORMS. THE REST OF THE FORECAST IS
ON TRACK. WILL ISSUE NEW ZONES MOMENTARILY.
UPDATE...
ISSUED AT 705 PM EDT TUE JUL 31 2012
AN ACTIVE AREA OF THUNDERSTORMS HAS FLARED UP THIS AFTERNOON. SOME OF
STORMS OVER LETCHER COUNTY BECAME SEVERE AND PUT DOWN SOME ONE INCH
HAIL AND DOWNED SOME TREE. SOME OF THE STORMS HAVE BEEN
TRAINING...AND AS SUCH...SOME FLOODING POTENTIAL HAS BE REALIZED. A
FLASH FLOOD WARNING WAS ISSUED FOR PIKE COUNTY...PARTLY BECAUSE OF
SOME OF THE HEAVY RAIN OVER BUCHANAN COUNTY FLOWED INTO THE AREA AND
THEN HEAVY RAIN DEVELOPED OVER PIKE COUNTY AS WELL. SOMETIMES
RADAR RAINFALL AMOUNTS ARE A BIT DUBIOUS BECAUSE OF HAIL
CONTAMINATION...HOWEVER THE FLASH FLOOD GUIDANCE FOR THAT AREA BEEN
MORE THAN DOUBLED BY RADAR ESTIMATES. AS THE THUNDERSTORMS MOVE
SOUTHEAST OUT OF THE AREA BY 9 PM...ANOTHER AREA OF STORMS WILL BE
MOVING INTO THE BLUE GRASS FROM THE NORTHWEST LATER TONIGHT. THE REST
OF THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 335 PM EDT TUE JUL 31 2012
CONVECTION THAT WAS OVER SE COUNTIES HAS DIMINISHED...THOUGH CU
REMAINS IN PLACE ACROSS THE SOUTHEASTERN COUNTIES. UPPER LEVEL
RIDGING REMAINS IN PLACE NEAR THE TX AND OK PANHANDLE REGIONS AT MID
AFTERNOON WITH TROUGH GENERALLY FROM CENTRAL CANADA DOWN THROUGH THE
GREAT LAKES TO THE EASTERN SEABOARD. NW FLOW ALOFT IS IN PLACE
BETWEEN THE TWO SYSTEMS. A SHORTWAVE IN THIS NW FLOW IS CURRENTLY
MOVING THROUGH ONTARIO AND THE GREAT LAKES REGION AND IS APPROACHING
THE UPPER OH RIVER VALLEY. AN OUTFLOW BOUNDARY FROM OVERNIGHT
CONVECTION HAS LOST SOME DEFINITION...BUT IS PROBABLY STILL IN PLACE
TO THE NORTHWEST OF THE REGION IN NORTHERN KY. FURTHER TO THE
NORTHWEST A COLD FRONT ASSOCIATED WITH THE SHORTWAVE MOVING THROUGH
THE GREAT LAKES IS STARTING TO APPROACH THE OH VALLEY.
THE SHORTWAVE WILL PASS BY TO THE NORTH AND NORTHEAST OF THE AREA
LATE THIS EVENING AND OVERNIGHT ALTHOUGH MODELS HINT AT ANOTHER WEAK
SHORTWAVE POSSIBLY MOVING ACROSS THE REGION ON WED AS WELL. INSTABILITY
PARAMETERS SUGGEST THAT ISOLATED CONVECTION COULD STILL DEVELOP OVER
THE SOUTHEASTERN COUNTIES OVER THE NEXT FEW HOURS. RECENT UPPER LEVEL
RADAR SCANS SUGGEST SHOWERS TRYING TO DEVELOP OVER THE SOUTHEASTERN
COUNTIES. OTHERWISE...CONVECTION THAT IS FORECAST TO DEVELOP OUR NW
IN ADVANCE OF THE COLD FRONT AND POSSIBLE DEVELOPMENT ALONG THE OLD
OUTFLOW SHOULD AFFECT THE NORTHWEST OR NORTHERN SECTIONS DURING THE
EVENING AS THE SHORTWAVE MOVES BY TO THE NORTHEAST. MEANWHILE COLD
FRONT NOW NORTHEAST OF THE OH VALLEY WILL DROP DOWN INTO THE REGION
TONIGHT AND WILL BECOME RATHER DIFFUSE BY WED...BUT STILL MAY BE A
FOCUS FOR CONVECTION IN THE FAR EAST...ESPECIALLY WHEN COUPLED BY
THE POTENTIAL SHORTWAVE CROSSING THE REGION. SFC AND UPPER LEVEL HIGH
PRESSURE BUILDING INTO THE AREA SHOULD LEAD TO DRY WEATHER FOR WED NIGHT.
CONFIDENCE IN AREAL EXTENT AND TIMING OF CONVECTION FROM LATE THIS
AFTERNOON INTO EARLY IN THE EVENING IS NOT ALL THAT HIGH...BUT SAT
AND RADAR TRENDS AS WELL AS SOME OF THE GUIDANCE SUGGESTS MORE
ACTIVITY THROUGH EARLY EVENING IN THE SOUTHEAST. THIS MAY THEN BE
FOLLOWED BY ISOLATED TO PERHAPS SCATTERED CONVECTION DURING THE MID
TO LATE EVENING OR EVEN OVERNIGHT...ESPECIALLY IN THE NORTH.
PATCHY FOG MAY DEVELOP TOWARD DAWN WHERE ANY PRECIP FALLS THIS
EVENING OR OVERNIGHT...AND THEN MORE TYPICAL VALLEY FOG ON WED NIGHT
WITH HIGH PRESSURE IN PLACE.
TEMPERATURES THROUGH THE PERIOD WILL AVERAGE A FEW DEGREES ABOVE
NORMAL.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 418 PM EDT TUE JUL 31 2012
WEAKENING SURFACE HIGH PRESSURE OVER THE REGION OVERLAID BY NW FLOW
ALOFT IS EXPECTED TO BRING DRY WX AND MAINLY CLEAR SKIES THURSDAY AND
THURSDAY NIGHT. AS THE HIGH CONTINUES TO WEAKEN...IT WILL LEAVE US IN
BETWEEN A LARGE SUBTROPICAL HIGH OVER THE ATLANTIC...AND LOW PRESSURE
OVER THE PLAINS WITH A COLD FRONT APPROACHING FROM THE NORTHERN
PLAINS. THE RESULTING WIND FLOW OVER THE LOCAL AREA WILL CARRY GULF
OF MEXICO MOISTURE NORTHWARD AGAIN...BRINGING INSTABILITY AND THE
POSSIBILITY OF SHOWERS AND THUNDERSTORMS. WILL USE ONLY 20-30 PERCENT
POP FRIDAY THROUGH SATURDAY NIGHT...DUE TO A LACK OF FEATURES AND LIGHT
FLOW ALOFT.
SUNDAY AND SUNDAY NIGHT AN UPPER TROUGH WILL MOVE ESE OVER THE GREAT
LAKES AND OHIO VALLEY...BRING THE AFOREMENTIONED SURFACE COLD FRONT
WITH IT. THE INCREASING FLOW ALOFT AND THE FOCUS FOR CONVECTIVE
INITIATION NEAR THE FRONT FRONT WILL PROVIDE A GREATER POP. THINK
THAT MOST PLACES WILL HAVE RAIN AT SOME POINT WITH THIS SYSTEM...BUT
HAVE USED 50 PERCENT FOR BOTH PERIODS FOR NOW. WANTED TO AVOID 60 YET
BECAUSE OF TIMING UNCERTAINTY AT THE EXTENDED TIME FRAME.
PRECIP COULD LINGER INTO MONDAY...ESPECIALLY IN THE SOUTHEAST...BUT
SHOULD END. DRY WEATHER AND SLIGHTLY LOWER HUMIDITY IS THEN EXPECTED
THROUGH TUESDAY AS SURFACE HIGH PRESSURE BUILDS IN BEHIND THE COLD
FRONT AND PASSES BY TO OUR NORTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 215 AM EDT WED AUG 1 2012
CONVECTION IS POPPING UP TO THE NORTHWEST OF PART OF THE FORECAST
AREA IN RELATION TO AN APPROACHING SFC BOUNDARY AND SOME ENERGY
ALOFT. HAVE PUSHED UP THE TIME OF THE VCSH IN THE EXISTING TAFS FOR
EARLY THIS MORNING. WILL HAVE TO MONITOR FOR A POSSIBLE VCTS AND CB
ADDITION AS THIS SCENARIO UNFOLDS OVER THE NEXT COUPLE OF HOURS. DO
EXPECT THE ACTIVITY TO SETTLE BY MID MORNING AND HAVE DROPPED ANY
MENTION OF PCPN BY THAT TIME. OTHERWISE...VFR CONDITIONS WILL
DOMINATE THROUGH THE PERIOD. DO STILL EXPECT TO SEE SOME PATCHY DENSE
VALLEY FOG LATE TONIGHT AND EARLY THIS MORNING...ESPECIALLY OVER
AREAS IN THE FAR SOUTHEAST THAT SAW THE RAIN YESTERDAY AFTERNOON...
BUT THE MAIN TAF SITES SHOULD REMAIN CLEAR. OUTSIDE OF ANY STRAY
THUNDERSTORMS...THE WINDS WILL BE LIGHT AND VARIABLE THROUGH THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JP
LONG TERM....HAL
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS GRAY ME
1220 AM EDT WED AUG 1 2012
.SYNOPSIS...
MID ATLANTIC LOW PRESSURE WILL MOVE ALONG THE NEW ENGLAND COAST
OVERNIGHT AND INTO THE CANADIAN MARITIMES WEDNESDAY. A WEAK COLD
FRONT WILL MOVE INTO THE REGION FROM THE WEST ON FRIDAY AND BECOME
STATIONARY THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...
HAVE UPDATED GRIDS BASED ON LATEST (DUAL POL) RADAR TRENDS AND
MOST RECENT SFC ANALYSIS. COASTAL LOW NOW WRAPPING BANDS OF RAIN
BACK TO THE COAST. HAVE RAISED POPS SIGNIFICANTLY FOR THIS REGION
AND PLACED LOCALLY UP TO A HALF INCH OF RAIN OVER THE NEXT FEW
HOURS IN THE REGION FOR QPF. PCPN SHOULD BEGIN TO WIND DOWN AROUND
SUNRISE AS LOW QUICKLY PULLS THROUGH THE GULF OF MAINE.
ONLY MINOR MODIFICATIONS TO THE REMAINDER OF THE GRIDS.
PREV DISC...
CUMULUS FIELD AND ISOLATED SHOWERS HAVE NOW
DEVELOPED OVER COOS COUNTY. THE HRRR MODEL INDICATES A FEW SHOWERS
AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE OVER THE HIGHER
TERRAIN FOR THE REMAINDER OF THE AFTERNOON.
NORTHERN NEW ENGLAND IS CAUGHT IN BETWEEN TWO SYSTEMS...ONE
LOCATED TO OUR WEST AND THE OTHER TO OUR SOUTH. A COASTAL LOW
PRESSURE SYSTEM WAS DEEPENING NEAR LONG ISLAND THIS AFTERNOON AND
WILL MOVE ALONG THE NEW ENGLAND COASTLINE OVERNIGHT. MODELS ARE IN
BETTER AGREEMENT THAT COASTAL AREAS AND AREAS AS FAR INLAND AS THE
FOOTHILLS WILL SEE PRECIPITATION OVERNIGHT. THE MIDCOAST AREA AS
WELL AS THE ISLANDS LOOK TO RECEIVE THE HIGHEST QPF AMOUNTS.
CURRENTLY DO NOT EXPECT THUNDERSTORMS...BUT THERE COULD BE A FEW
STRIKES OFFSHORE CLOSER TO THE CORE OF THE SYSTEM. WIDESPREAD FOG
AND CLOUDY CONDITIONS WILL KEEP TEMPERATURES ON THE WARM SIDE
OVERNIGHT.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
THE COASTAL LOW WILL BE JUST OFFSHORE TOMORROW MORNING AND WILL
MOVE INTO THE CANADIAN MARITIMES BY EARLY AFTERNOON. AS SHOWERS
END OVER THE MIDCOAST REGION (ASSOCIATED WITH THE COASTAL LOW)
THEY WILL BEGIN TO CREEP INTO NEW HAMPSHIRE AND WESTERN MAINE
AHEAD OF THE COLD FRONT.
PW VALUES INCREASE TO NEAR 1.75 INCHES INDICATING POOLING MOISTURE
AHEAD OF THE APPROACHING COLD FRONT TO OUR WEST. FORECAST SKEW T
PROFILES SHOW SKINNY CAPE...WARM CLOUD LAYERS...AND VERY LIGHT
WINDS. THIS ALL POINTS TOWARDS POSSIBLE FLASH FLOODING PROBLEMS.
INSTABILITY WILL BE HIGH ENOUGH FOR SCATTERED THUNDERSTORMS.
HIGH TEMPERATURES SHOULD REACH THE UPPER 70S/LOWER 80S TOMORROW
WITH LOW TEMPERATURES IN THE UPPER 50S TO MID 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
COLD FRONT STALLS IN THE NORTHWESTERN PART OF THE AREA ON
THURSDAY... A SECOND AREA OF LOW PRESSURE PASSES OFFSHORE OF CAPE
COD DURING THE DAY. MOST OF THE RAIN WITH THIS LOW WILL STAY
OFFSHORE... BUT INSTABILITY AND LIFT ASSOCIATED WITH THE
DISSIPATING COLD FRONT AND A PASSING UPPER LEVEL SHORTWAVE TROUGH
MAY LEAD TO A FEW SHOWERS OR THUNDERSTORMS IN INLAND AREAS.
AS THE UPPER LEVEL TROUGH PUSHES EAST... A COLD FRONT WILL PUSH
SOUTHWARD INTO NORTHERN NEW ENGLAND ON FRIDAY... WITH SHOWERS AND
THUNDERSTORMS POSSIBLE ALONG AND AHEAD OF IT. THE FRONT STALLS AS
IT GETS CLOSER TO THE COAST ON SATURDAY AND WEAKENS.
LARGER TROUGH ALOFT PUSHES EASTWARD OUT OF THE GREAT LAKES SUNDAY
INTO MONDAY... WITH LIFT AHEAD OF THIS SYSTEM PROVIDING INCREASED
CHANCES FOR SHOWERS AND THUNDERSTORMS. THUNDERSTORMS WILL BE MOST
LIKELY ON MONDAY AHEAD OF A MORE PRONOUNCED COLD FRONT.
TEMPERATURES THROUGH THE PERIOD WILL REMAIN ABOVE NORMAL AS THE
JET STREAM STAYS NORTH AND WARM... MOIST AIR CONTINUES TO FLOW
INTO NEW ENGLAND.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...GUSTY SOUTHERLY WINDS THIS AFTERNOON WITH VFR
CONDITIONS CONTINUING. LOWERING CEILINGS AND VISIBILITIES WILL
ARRIVE AS LOW PRESSURE MOVES ALONG THE NEW ENGLAND COASTLINE
TONIGHT. LIFR/IFR CONDITIONS LIKELY AT ALL TERMINALS JUST PRIOR TO
MIDNIGHT WITH SHOWERS EVERYWHERE EXCEPT KHIE...KLEB...AND KCON.
LONG TERM...GENERALLY VFR EXPECTED... BUT WITH INCREASING MOISTURE
LEVELS INTO THE WEEKEND... NOCTURNAL FOG WILL BECOME MORE AND MORE
LIKELY ESPECIALLY IN TRADITIONALLY FAVORED AREAS LIKE WHITEFIELD
AND LEBANON.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL FALL JUST SHORT OF SMALL CRAFT
THRESHOLDS LATE TONIGHT INTO WEDNESDAY AS LOW PRESSURE CROSSES
THE GULF OF MAINE.
LONG TERM...LOW PRESSURE PASSES EAST OF CAPE COD AND INTO NOVA
SCOTIA AGAIN ON THURSDAY. BUT WINDS SHOULD STAY BELOW 20 KT. HIGH
PRESSURE OVER THE ATLANTIC BRINGS A LIGHT SOUTHERLY FLOW THROUGH
THE WEEKEND.
&&
.EQUIPMENT...
THE DUAL POLARIZATION RADAR INSTALLATION AT THE NATIONAL
WEATHER SERVICE SITE IN GRAY MAINE IS IN PROGRESS. GRAY MAINE
/KGYX/ RADAR DATA WILL NOT BE AVAILABLE FOR ANOTHER DAY OR TWO
DURING THE INSTALLATION AND FOLLOW UP TESTING OF THIS NEW
EQUIPMENT.
STILL MISSING OBSERVATIONS. ISSUE IS BEING WORKED ON ATTM.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
154 AM EDT WED AUG 1 2012
.SYNOPSIS...
LOW PRESSURE ALOFT AND A WARM AND HUMID AIRMASS WILL PERSIST
ALONG THE EASTERN SEABOARD THIS WEEK. A WEAK COLD FRONT WILL
APPROACH THE MID-ATLANTIC REGION ON WEDNESDAY. A SECOND FRONTAL
BOUNDARY IS EXPECTED TO CROSS THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
BROKEN LINE OF THUNDERSTORMS CONTINUE TO DROP SOUTHEAST THROUGH
CENTRAL VIRGINIA. MUCAPE OVER EASTERN LWX CWA IS STILL 1500 TO
2000 J/KG ACCORDING TO RAP MODEL ON SPC MESO PAGE. STRATIFORM
APPROACHING DC MAY BE ALL THE METRO AREA GETS. HOWEVER...THE
SCATTERED THUNDERSTORMS THAT DEVELOPED OVER THE PAST HALF HOUR
EAST OF BALTIMORE IS INDICATIVE OF THE REMNANT INSTABILITY.
THROUGH THE MIDNIGHT HOUR ACTIVITY IS THE MAIN FEATURE
TONIGHT...WITH ONLY ISOLATED ACTIVITY AT BEST AFTERWARDS. EXPECT
AT LEAST PATCHY FOG IN THE WAKE OF THE THUNDERSTORMS.
WITH STAGNANT AMS...CU FIELD SHOULD DVLP QUICKLY AGAIN WED MRNG.
SHWRS AND TSTMS ONCE AGAIN CAN BE XPCD DURG THE DAY ON WED WITH
TROF RMNG ALONG APLCNS AND WEAK CDFNT APRCHG RGN. THERE IS SOME
UNCERTAINTY AS TO THE SWD ADVCMT OF THE BNDRY DURG THE DAY...SO
POPS WERE FOCUSED IN NWRN PORTION OF FCST AREA. MAXIMA IN MID-UPR
80S XPCD.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
UPPER-LEVEL AND SFC TROUGH WILL MOVE OFFSHORE THU...ALLOWING THE
MID-ATLC TO DRY OUT FOR A COUPLE OF DAYS. OUTSIDE OF A WEAK SFC
TROUGH THAT WILL DRIFT OVER THE AREA LATE THU INTO FRI...THE AREA
SHOULD BE FAIRLY QUIET. THIS WILL ALLOW FOR A BIT OF A WARM-UP
BOTH DAYS... ESPECIALLY FRI. HUMIDITY VALUES WILL NOT CHALLENGE
SOME OF THE HOTTER VALUES THIS YEAR...BUT TEMPS AND HEAT INDICES
WILL APPROACH THE M90S EACH AFTN.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE MAIN STORY FOR NEXT WEEKEND WILL BE THE BUILD-UP TO A FRONTAL
PASSAGE ON MONDAY. A POTENT LOW PRESSURE SYSTEM WILL SWING DOWN FROM
THE CANADIAN ROCKIES LATE THIS WEEK...DRAGGING ALONG THE US/CANADA
BORDER THIS WEEKEND. AS THE SYSTEM APPROACHES...A LARGE BERMUDA HIGH
WILL CREATE A FETCH OF WARM-MOIST AIR UP THE EASTERN SEABOARD BOTH
SAT AND SUN. SHOWERS AND TSTMS OF AN ISOLATED NATURE WILL BE
POSSIBLE EACH DAY THIS WEEKEND...ALONG WITH HIGHS IN THE L90S HIGHER
HUMIDITY THAN IN PAST DAYS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
MVFR LEVELS ARE POSSIBLE OVERNIGHT AT CHO AND MRB AS THE AIR REMAINS
SATURATED AFTER EVENING SHOWERS/TSTORMS. WITH OVC TO BKN CLOUD COVER
OVER THE AREA...EXPECT COOLING TO BE GRADUAL AND ONLY MVFR
REDUCTIONS IN VSBY. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
THROUGH THE DAY TOMORROW WILL REDUCE VSBY TO IFR LEVELS AT TIMES
ACROSS AREA TERMINALS. PRECIP SHOULD END WED AFTERNOON WITH SKIES
BEGINNING TO CLEAR. WIND WILL REMAIN LIGHT OVERALL EXCEPT FOR
OCCASIONAL 7KT GUSTS DEVELOPING FROM THE SOUTH WED AFTERNOON.
THESE GUSTS WILL DIMINISH INTO THE EVENING HOURS.
A COUPLE OF DRY DAYS TO CLOSE OUT THE WORK WEEK...AS HIGH PRESSURE
BRIEFLY BUILDS IN ACROSS THE REGION. THE WEEKEND WILL SEE THE RETURN
OF MOISTURE AND CUMULUS FIELD...ALONG WITH ISOLATED TSTMS. A LOW
PRESSURE SYSTEM APPROACHES FROM THE GREAT LAKES THIS WEEKEND...
DRAGGING A COLD FRONT ACROSS THE AREA ON MONDAY.
&&
.MARINE...
ISOLATED THUNDERSTORMS EXPECTED ACROSS THE WATERS THROUGH 2AM.
ADDITIONAL SPECIAL MARINE WARNINGS ARE POSSIBLE. SLY FLOW WILL
CONTINUE TO GUST AROUND 15 KT THROUGH WEDNESDAY.
GENERALLY LIGHT SLY WINDS LATE THIS WEEK INTO THE WEEKEND...THOUGH
SLY CHANNELING WILL OCCUR EACH AFTN/EVE. A COLD FRONT WILL THEN
MOVE ACROSS THE AREA LATE MON INTO TUE OF NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
ISSUED A COASTAL FLOOD ADVISORY FOR ANNAPOLIS AND ALEXANDRIA. WATER
LEVELS ARE AROUND THREE QUARTERS OF A FOOT ABOVE PREDICTED LEVELS
TONIGHT IN THIS WAXING GIBBOUS MOON PHASE. THE MOST SENSITIVE
LOCATIONS OF ALEXANDRIA AND ANNAPOLIS WILL PROBABLY HIT THEIR
MINOR THRESHOLDS OVER THE NEXT COUPLE OF HOURS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MDZ014.
VA...COASTAL FLOOD ADVISORY FROM 6 AM TO 10 AM EDT THIS MORNING FOR
VAZ054.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...JACKSON/CLS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
349 AM EDT WED AUG 1 2012
.SYNOPSIS...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL DRIFT THROUGH THE GREAT LAKES REGION TODAY...
BRINGING SEASONABLY WARM AND DRY CONDITIONS. MEANWHILE...THE NEXT
LOW PRESSURE SYSTEM AND COOL FRONT...WILL MIGRATE ALONG THE CANADIAN
BORDER. THIS LOW WILL MOVE THROUGH TONIGHT...WITH ITS TRAILING COOL
FRONT SLIDING THROUGH THURSDAY. SCATTERED SHOWERS AND STORMS...WILL
ACCOMPANY THIS FRONT. HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...BUT THE COOL FRONT WILL BECOME STATIONARY...JUST SOUTH OF
THE REGION...WITH NORTHERN PLAINS LOW PRESSURE APPROACHING FROM THE
WEST. THE NEXT CHANCE OF RAIN...WILL APPROACH WITH THIS SYSTEM OVER
THE WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 348 AM EDT WED AUG 1 2012
TROUGHING OVER THE EASTERN COUNTRY AND AN UPPER RIDGE OVER THE
PLAINS...LEADS TO CONTINUED NW FLOW ALOFT INTO THE GREAT LAKES.
ONE SHORTWAVE IS WORKING ACROSS SRN ONTARIO AND IS ASSOCIATED
WITH AN AREA OF INCREASED UPPER LEVEL MOISTURE SEEN ON LATEST WV
IMAGERY. THIS FEATURE IS RUNNING INTO SOME MINOR UPPER RIDGING
OVER NRN MICHIGAN AND ASSOCIATED CLOUDS IN THE HIGHER LEVELS HAS
BEEN WANING WITH TIME. A STRONGER MORE DEFINED SHORTWAVE IS SEEN
IN MANITOBA ALSO PER SATELLITE DATA...AND IN RUC ANALYSES FOCUSED
AROUND 700MB. THIS WAVE IS WORKING ON A WARM FRONT EXTENDING EAST
FROM A SFC LOW IN SRN MANITOBA. MAXIMUM LOW LEVEL CONVERGENCE
ASSOCIATED WITH A LLJ POINTING INTO THIS REGION AND WESTERN ONTARIO
HAS RESULTED IN AN MCS WITH A SWATH OF SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS. SKIES ARE CLEAR HERE...WITH ONLY SOME PATCHY HIGH
LEVEL CLOUDS SCRAPING EASTERN UPPER. ALTHOUGH SFC BASED MOISTURE
LINGERS IN THE NORTH WOODS (TDS IN THE 50S AND EVEN LOW 60S)...THE
LOW LEVEL MOISTURE PROFILE SHOWS DRYING FROM ALOFT. THIS HAS HELD
FOG DEVELOPMENT IN CHECK FROM AN AERIAL PERSPECTIVE.
TODAY...NO CONCERNS. HIGH PRESSURE AND LIGHT WINDS CURRENTLY OVER
THE FAR WESTERN GREAT LAKES WILL GRADUALLY WORK IN OVER THE SW
CWA/GTV BAY REGION THROUGH THE DAY. THIS WILL BRING A RETURN TO
SOUTHERLY WINDS THAT INCREASE MORE SO ACROSS EASTERN UPPER. A
LIGHTER WIND REGIME ACROSS NRN LOWER WILL LEAD TO THE DEVELOPMENT
OF LAKE BREEZES AND CONVERGENCE ACROSS NE LOWER. ONE WOULD TEND TO
BELIEVE THAT CUMULUS WILL BE MORE SO CONFINED TO THIS AREA.
HOWEVER...THE LOW LEVEL AIR MASS PROFILE (GENERALLY 700MB AND
BELOW)...IS QUITE DRY. CUMULUS WILL BE HARD TO COME BY WITH MAYBE
JUST SOME STRANDS OF CIRRUS OVERHEAD. A TRULY DECENT SUMMERTIME
DAY WITH TEMPERATURES IN THE WARMER SOUTHERLY FLOW RISING INTO THE
MID AND UPPER 80S ALL AREAS...OUTSIDE OF ONSHORE FLOW CREATED BY
MESOSCALE LAKE BREEZE/ONSHORE FLOW.
BY TONIGHT...THE LOW PRESSURE FROM MANITOBA WILL HAVE SHIFTED
ACROSS SRN MANITOBA...WITH A PRE-FRONTAL TROUGH/COLD FRONT AND
AXIS OF HIGHER THETA-E AIR TO LAY ACROSS EASTERN UPPER IN THE LATE
EVENING...AND ULTIMATELY IN NRN LOWER OVERNIGHT. THE UPPER WAVE
BECOMES SLIGHTLY MORE SHARP TONIGHT...AND THE THETA-E AIR
INCREASES IN THE EVENING BEFORE LOWERING OVERNIGHT...AS
CONVERGENCE ALONG THE TROUGH/COLD FRONT WANES IN THE DEPARTURE OF
THE SHORTWAVE ALOFT. FROM A PATTERN PERSPECTIVE...APPEARS AS
THOUGH THIS SCENARIO LEADS TO BEST CHANCES FOR SEEING
PRECIPITATION WILL BE ACROSS EASTERN UPPER AND FAR NRN LOWER
MICHIGAN WHEN FORCING IS MAXIMIZED WITH GREATEST MOISTURE/WARMTH
AND INSTABILITY (MUCAPES NEARING 1200 J/KG). POPS WILL DECREASE
NEARER THE SAGINAW BAY AS THE SHORTWAVE FORCING AND LOW LEVEL
CONVERGENCE MAXIMUMS DON`T QUITE REACH. REGARDLESS...THE BOUNDARY
DOES WORK THROUGH THIS AREA AS WELL. THE PRECIPITATION PICTURE
BEING PAINTED HERE IS FOR BEST/AND MOST PROLONGED CHANCE FOR
SEEING SHOWERS AND STORMS IN THE NRN HALF OF THE CWA. WILL KEEP
TREND OF ONLY 40% CHANCE THERE WITH 30% FURTHER SOUTH. JUST HAVE
TOO MANY CONCERNS REVOLVING AROUND ANTECEDENT RELATIVELY DRY AIR
MASS...ESPECIALLY THE LOW LEVELS WHICH DON`T EXACTLY DON`T BLOW MY
MIND IN A MOISTURE ADVECTION PERSPECTIVE. THIS FURTHER SUPPORTED
BY LACK OF/NO FGEN IN THE H8-H5 LAYER. ALL-IN-ALL...THIS IS
SEEMINGLY A LACKLUSTER EFFORT FOR PRECIPITATION. CAN FORESEE A HIT
AND MISS SHOWERY IDEA NORTH...WITH DECAYING/LESS AREAL COVERAGE
FURTHER SOUTH INTO THE PRE-DAWN HOURS HOURS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 348 AM EDT WED AUG 1 2012
NORTHERN HEMISPHERIC LARGE SCALE PATTERN CONFIGURATION ENSURES
CURRENT NOAM PATTERN IN NO HURRY TO CHANGE ANYTIME SOON...PLACING
THE NORTHERN LAKES IN PERSISTENT...AND AT TIMES ACTIVE...NORTHWEST
FLOW REGIME THROUGH THE REMAINDER OF THE WORK WEEK. CONSISTENT MID
RANGE GUIDANCE SUPPORT FOR SOME RELAXATION IN EASTERN NOAM TROUGHING
OVER THE WEEKEND...ALLOWING RATHER POTENT SHORTWAVE TO DIVE INTO THE
NORTHERN PLAINS...FORCING DOWNSTREAM HEIGHT RISES AND MORE
IMPRESSIVE SURGE OF LOW LEVEL MOISTURE INTO THE REGION. THIS SETS
THE STAGE FOR A POTENTIALLY ACTIVE (SEVERE WEATHER?) WEEKEND AS SAID
WAVES PLOWS THROUGH A SEASONABLY MOIST...INCREASINGLY UNSTABLE
AIRMASS. IN LIGHT OF THE ABOVE...FORECAST CONCERNS CENTER ON
MULTI-PERIOD PRECIP POTENTIAL...AS WELL AS TEMPERATURE AND CLOUD
TRENDS THROUGHOUT.
START OF THE PERIOD SHAPING UP TO BE SOMEWHAT ACTIVE AS LOW
AMPLITUDE WAVE AND ATTENDANT SURFACE LOW DRAG A SLOW MOVING COLD
FRONT SOUTH ACROSS THE MITT THURSDAY. ALTHOUGH BEST MID LEVEL
SUPPORT ACTUALLY PUSHES EAST EARLY...STILL NICE ENOUGH TRIFECTA OF
WEAKISH RER JET DYNAMICS...FRONTAL INDUCED CONVERGENCE...AND FOLDING
OVER THETA-E RIDGE TO SUPPORT INHERITED SHOWER AND THUNDERSTORM
THREAT. GREATEST POTENTIAL LIKELY SOUTH OF THE BIG BRIDGE...
ESPECIALLY IN THE ALL-TO-OFTEN FAVORED NORTHEAST LOWER WHERE LOW
LEVEL CONVERGENCE WILL BE MAXIMIZED. ML CAPE VALUES HOVERING AROUND
1K J/KG AND CORE OF BULK SHEAR REMAINING POST-FRONTAL AND TO OUR
NORTH SUGGEST STORMS SHOULD BEHAVE THEMSELVES. UNCERTAINTY INCREASES
TO ROUND OUT THE WORK WEEK. WHILE GUIDANCE TRENDS AGREE SURFACE
FRONT WILL PUSH SOUTH OF THE REGION (CONVECTIVE OUTFLOW ENHANCED?)
AS HIGH PRESSURE ROTATES SOUTHEAST ACROSS ONTARIO....SAME CANNOT BE
SAID FOR OFF THE DECK CONVERGENCE AXES AND CORE OF DEEPER MOISTURE.
SOME EVIDENCE THESE WILL RESIDE CLOSE ENOUGH TO KEEP AT LEAST A LOW
END SHOWER/STORM THREAT THURSDAY NIGHT INTO FRIDAY. WILL NOT GO THIS
ROUTE JUST YET (PROBS JUST TOO LOW)...BUT SOMETHING TO KEEP IN MIND
AS WE HEAD TOWARDS THE WEEKEND.
AS FOR THE WEEKEND...POTENTIALLY THE MOST "INTERESTING" PORTION OF
THE FORECAST AS GUIDANCE REMAINS AMAZINGLY STEADFAST PINWHEELING A
STRONG SHORTWAVE TROUGH THROUGH THE NORTHERN LAKES LATER SATURDAY
INTO SUNDAY. RETURN FLOW LOOKS TO BE WELL ESTABLISHED AHEAD OF THIS
FEATURE...WITH PERUSAL OF AVAILABLE MOISTURE PROGS SUGGESTING PWAT
VALUES AOA 1.50 INCHES. DYNAMICS LOOK PRETTY FORMIDABLE...WITH NEAR
NEUTRAL TILT WAVE AND POSSIBLE RER JET DYNAMICS OVERTOPPING A
SEASONABLY STRONG COLD FRONT. STILL SOME MINOR TIMING DIFFERENCES
WITH ALL THE ABOVE...BUT OVERALL A PRETTY WELL AGREED UPON FORECAST.
NO DOUBT A MODEL CONSENSUS WILL SUFFICE...FEATURING POSSIBLE SHOWERS
AND STORMS THROUGH THE WEEKEND...WITH THE GREATEST POTENTIAL
OVERNIGHT SATURDAY INTO EARLY SUNDAY. MUCH TOO EARLY TO GET CAUGHT
UP IN INSTABILITY PROGS AND SPECIFIC MID LEVEL WIND CORES...BUT FROM
A PATTERN RECOGNITION STANDPOINT...THIS SYSTEM LOOKS TO HAVE THE
POTENTIAL TO DRIVE A RATHER VIGOROUS (SEVERE?) SQUALL LINE THROUGH
AT LEAST A PORTION OF THE LAKES REGION. FRONTAL TIMING (CURRENT
TRENDS SUPPORT AN UNFAVORABLE EARLY SUNDAY MORNING FRONTAL PASSAGE)
MIGHT NOT EVEN MATTER MUCH GIVEN SUGGESTED DYNAMICS. DEFINITELY
SOMETHING TO MONITOR IN THE COMING DAYS. DRY WEATHER RETURNS FOR THE
BEGINNING OF NEXT WORK WEEK WITH AN AGGRESSIVE PUSH OF HIGH PRESSURE
BUILDING IN BEHIND THE DEPARTING FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 145 AM EDT WED AUG 1 2012
MAINLY VFR CONDITIONS ARE EXPECTED THRU WEDNESDAY EVENING AS HIGH
PRESSURE BUILDS INTO MICHIGAN. FOG WILL CONTINUOUSLY IMPACT MBL
AND LIKELY PLN OVER THE NEXT HOUR OR SO...EVEN TVC HAS A DECENT
SHOT WITH HIGH PRESSURE AND LIGHT WINDS AND SMALL TEMP/DEW POINT
SPREADS. LAKE BREEZES WILL DEVELOP BY WEDNESDAY AFTERNOON. OUR
NEXT CHANCE OF SHRA/TSRA WILL DEVELOP LATE WEDNESDAY NIGHT AS A
WEAK FRONT DROPS INTO NRN MICHIGAN. STILL APPEARS BETTER CHANCES
OF PRECIP WILL HOLD OFF UNTIL AFTER 06Z THURSDAY...THUS WILL LEAVE
PRECIP CHANCES OUT OF TAFS FOR NOW.
&&
.MARINE...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL SLIP SOUTH AND EAST OF THE REGION
TODAY...ALLOWING A SOUTHERLY AND INCREASING WIND FLOW TO
REINTRODUCE A HIGHER MOISTURE CONTENT TO THE GREAT LAKES. A COLD
FRONT ARRIVING LATE TONIGHT WILL WORK ON THIS AIR MASS AND BRING A
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO THE AREA. THE
PRESSURE GRADIENT TIGHTENS UP ENOUGH IN A NEUTRAL STABILITY
SCENARIO FOR A CHANCE AT LOW END SMALL CRAFT ADVISORIES LATER
TONIGHT. WILL NOT INTRODUCE THIS JUST YET...BUT COASTAL CONVERGENT
REGIONS OF NW LOWER MICHIGAN WILL BE THE BEST SHOT AT +25KT GUSTS.
THIS FRONT CONTINUES TO DIVE SOUTH OF US INTO THURSDAY...BEFORE
LIFTING BACK AS A WARM FRONT LATE FRIDAY NIGHT AND INTO THE
WEEKEND. NO OTHER WIND ISSUES ARE FORESEEN THROUGH THE WORK
WEEK...BUT ADVISORIES MAY BE NEEDED FOR THE WEEKEND AHEAD OF NEXT
MORE POTENT COLD FRONT...BOTH AHEAD OF AND BEHIND THIS BOUNDARY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...MB
SHORT TERM...SD
LONG TERM...MB
AVIATION...MR
MARINE...SD
AREA FORECAST DISCUSSION
NWS DULUTH MN
337 AM CDT WED AUG 1 2012
.SHORT TERM...
TODAY THROUGH THURSDAY AFTERNOON...
MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS TODAY...WITH A SLIGHT RISK OF STRONG
TO SEVERE STORMS SOUTH OF A LINE FROM HINCKLEY TO ASHLAND...ALONG
WITH VERY WARM AND HUMID CONDITIONS TODAY...AND A FEW SHOWERS AND
STORMS POSSIBLE ACROSS THE ARROWHEAD TOMORROW.
SURFACE HIGH PRESSURE AND DRY CONDITIONS ARE DOMINATING MUCH OF
THE WRN GREAT LAKES REGION THIS MORNING...WITH THE HIGH CENTERED
OVER CENTRAL WI. A LARGE UPPER LOW IS SITUATED OVER HUDSON BAY AND
AN UPPER HIGH IS POSITIONED OVER THE SRN PLAINS. A COUPLE WEAK
SHORT WAVES ARE RIDING IN BETWEEN THESE TWO FEATURES ACROSS THE
NRN PLAINS AND UPPER MIDWEST. A SFC LOW IS LOCATED OVER SRN
MANITOBA WITH A STATIONARY/WARM FRONT EXTENDING EWD INTO NRN
ONTARIO AND A TROUGH/COLD FRONT DROPPING SOUTH INTO THE DAKOTAS.
THIS LOW PRESSURE SYSTEM WILL CONTINUE TO TRACK EWD INTO THE
NORTHLAND TODAY AND EVENTUALLY TRIGGER SHOWERS AND STORMS ALONG
AND AHEAD OF THE FRONT.
THERE ARE SIGNIFICANT MODEL DIFFERENCES REGARDING THE CONVECTIVE
INITIATION THIS AFTERNOON...WITH THE 00Z GFS NAM AND ECMWF BEING
FAIRLY MORE AGGRESSIVE THAN THE 00Z GEM AND LATEST 06Z NAM. THE
MORE AGGRESSIVE MODELS ARE NOT INITIALIZING VERY WELL LOOKING AT
CURRENT REGIONAL RADAR...SO CONFIDENCE IN CHC POPS/SCT SHOWERS AND
STORMS IS MUCH WEAKER. UPPER LEVEL SUPPORT IS NOT REALLY EVIDENT
WITH A WEAK JET AND MINIMAL 500MB PVA. THE LOW LEVELS WILL BECOME
QUITE UNSTABLE WITH ML CAPE VALUES OVER 2000 J/KG AND 0-6KM SHEAR
AROUND 30 KT...ALONG WITH STEEP LAPSE RATES...WHICH WILL PROVIDE
THE NECESSARY INGREDIENTS FOR STRONG CONVECTION. SO...WILL LIKELY
SEE SHOWERS AND WEAK STORMS INITIATE ACROSS NE MN INTO CENTRAL MN
AND MOVE E/SEWD WITH THE FRONT AND POSSIBLY INTERACT WITH AN
INCREASINGLY UNSTABLE ATMOSPHERE TO PRODUCE A FEW STRONG TO
POSSIBLY SEVERE STORMS OVER THE SERN SECTIONS OF THE CWA...MAINLY
IN NW WI. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS.
CHECK THE LATEST DAY 1 CONVECTIVE OUTLOOK FROM SPC FOR FURTHER
INFORMATION.
THE OTHER CONCERN TODAY WILL BE THE HOT AND HUMID CONDITIONS ONCE
AGAIN. WE JUST ENDED THE SECOND WARMEST JULY ON RECORD IN DULUTH
YESTERDAY...AND NOW WE ARE STARTING OFF AUGUST ON A WARM NOTE AS
WELL. HIGHS WILL CLIMB INTO THE MID TO UPPER 80S WITH DEW POINTS
INTO THE MID TO UPPER 60S. THIS WILL CAUSE HEAT INDICES TO ROCKET
INTO THE LOWER TO MID 90S. TAKE THE NECESSARY PRECAUTIONS IF
OUTSIDE TODAY.
WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING SYSTEM
TONIGHT AND ALLOW CONDITIONS TO DRY OUT RAPIDLY. ANOTHER WEAK
UPPER WAVE SLIDES IN FROM THE NW TOMORROW AFTERNOON AND INTERACTS
WITH A WEAKLY UNSTABLE ATMOSPHERE TO TRIGGER OFF A FEW ISOLATED
STORMS ACROSS THE ARROWHEAD. AT THIS TIME CONFIDENCE IS LOW IN
PRECIP ON THURSDAY AFTERNOON. TEMPERATURES WILL BE SLIGHTLY COOLER
ON THURSDAY WITH LOWER...MORE COMFORTABLE HUMIDITIES. HIGHS WILL
ONLY REACH INTO THE LOWER TO MID 80S.
.LONG TERM...
THURSDAY NIGHT THROUGH WEDNESDAY...
SFC RIDGING OVER THE EASTERN GREAT LAKES WILL KEEP THE FA DRY
THURSDAY NIGHT. ON FRIDAY...A LARGE CUT OFF UPPER LOW MOVES OUT OF
THE CANADIAN ROCKIES INTO THE CANADIAN PLAINS. THIS WILL PUSH A SFC
LOW CENTER OVER THE NORTHERN RED RIVER VALLEY IN CANADA WHILE A SFC
FRONT MOVES INTO THE RED RIVER VALLEY. PLENTY OF LOW LEVEL MOISTURE
WILL BE TRANSPORTED INTO THE FA AHEAD OF THE FRONT. SHOWERS AND
STORMS WILL FORM AHEAD OF THE FRONT AND OVERSPREAD THE FA THROUGH
FRIDAY NIGHT. THE COLD FRONT DEPARTS THE FA ON SATURDAY AS THE SFC
LOW OPENS UP AND THE UPPER LOW CONTINUES TO DRIVE EASTWARD THROUGH
SOUTH CENTRAL CANADA. A SECONDARY COLD FRONT WITH COLDER AIR ALOFT
FOLLOWS BEHIND AND CROSS THE FA SATURDAY NIGHT. SOME ISOLD
THUNDERSTORMS WILL ACCOMPANY THIS FRONT. A DRY PERIOD FOLLOWS FOR
SUNDAY THROUGH WEDNESDAY AS UPPER LEVEL/SFC RIDGING COVER THE
WESTERN GREAT LAKES.
&&
.AVIATION.../06Z TAF ISSUANCE/
PULLED OUT THE LLWS OVERNIGHT AS LATEST NAM BUFR SOUNDINGS SHOW
WIND SPEEDS UNDER 30 KNOTS BELOW 2000 FT AGL. ALSO SHIFTED THE
TIMING OF VCTS TO THE MORNING HOURS AS LATEST HRRR REFLECTIVITY
BRINGS IN SOME THUNDER AFTER 10Z ACROSS THE WESTERN AERODROMES.
A COLD FRONT WILL PASS THROUGH THE TERMINALS BY 18Z THAT WILL
BRING IN WESTERLY WINDS WITH A FEW GUSTS NEARING 20 KNOTS. WINDS
WILL DIMINISH BEFORE SUNSET AND COME FROM THE NORTHWEST.
&&
.POINT TEMPS/POPS...
DLH 87 64 80 57 / 40 30 10 0
INL 86 57 79 56 / 30 10 20 0
BRD 89 64 84 60 / 40 20 10 0
HYR 89 62 84 58 / 30 40 10 0
ASX 89 64 82 59 / 40 40 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...TENTINGER
LONG TERM....GSF
AVIATION...KK
AREA FORECAST DISCUSSION
NWS DULUTH MN
1225 AM CDT WED AUG 1 2012
.AVIATION.../06Z TAF ISSUANCE/
PULLED OUT THE LLWS OVERNIGHT AS LATEST NAM BUFR SOUNDINGS SHOW
WIND SPEEDS UNDER 30 KNOTS BELOW 2000 FT AGL. ALSO SHIFTED THE
TIMING OF VCTS TO THE MORNING HOURS AS LATEST HRRR REFLECTIVITY
BRINGS IN SOME THUNDER AFTER 10Z ACROSS THE WESTERN AERODROMES.
A COLD FRONT WILL PASS THROUGH THE TERMINALS BY 18Z THAT WILL
BRING IN WESTERLY WINDS WITH A FEW GUSTS NEARING 20 KNOTS. WINDS
WILL DIMINISH BEFORE SUNSET AND COME FROM THE NORTHWEST.
&&
.PREV DISCUSSION... /ISSUED 731 PM CDT TUE JUL 31 2012/
UPDATE...
WE PULLED POPS FOR EARLY THIS EVENING...AND HAVE A SLIGHT CHANCE
FOR A SHOWER/STORM IN THE FAR NORTHWEST LATE THIS EVENING...THEN
CONTINUED TO SPREAD POPS FURTHER EAST AND SOUTH OVERNIGHT.
INITIAL WEAK WAVE THAT COMBINED WITH WAA TO PRODUCE A FEW
SHOWERS/STORMS IN NORTHWEST MN HAS MOVED EAST AND INTO MORE STABLE
AIR. MODELS FORECAST INCREASING LLJ WITH 925MB WINDS INCREASING TO
35-40KT AS FRONT MOVES EAST INTO NORTHWEST MINNESOTA BY 12Z WED.
STABILITY WILL BE DROPPING OVERNIGHT. THERE REALLY ISN`T MUCH OF A
MID LEVEL WAVE TO AID IN LARGER SCALE FORCING TONIGHT...SO THERE
ARE SOME DOUBTS AS TO COVERAGE AND STRENGTH OF THE STORMS
OVERNIGHT. WE WILL KEEP POPS AS IS FOR NOW FOR LATER TONIGHT...AND
WAIT FOR THE LATEST MODELS BEFORE MAKING ANY FURTHER ADJUSTMENT.
PREV DISCUSSION... /ISSUED 624 PM CDT TUE JUL 31 2012/
AVIATION.../0Z TAF ISSUANCE/
MARGINAL LLWS TONIGHT OVER THE PARTS OF THE AREA TONIGHT AND KEPT
THE THREAT OF SOUTHWEST WINDS OF 30 KNOTS UP TO 2000 FT AGL OVER
BRD AND HIB AFTER MIDNIGHT. ANY PATCHY FOG THAT DOES DEVELOP
TONIGHT SHOULD BE LIMITED TO HYR WHERE VISIBILITIES MAY FALL TO
LOW END MVFR RANGE BY DAYBREAK. INCLUDED A TEMPO GROUP AFTER
MIDNIGHT FOR THUNDERSTORMS AT INL AND HAVE VCTS FOR ALL TERMINALS
BY EARLY WEDNESDAY AFTERNOON.
PREV DISCUSSION... /ISSUED 342 PM CDT TUE JUL 31 2012/
SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT.
SOME HIGH CLOUDS HAVE MOVED ACROSS THE NORTHLAND DURING THE
AFTERNOON ALONG WITH SOME CUMULUS DEVELOPMENT. THERE WERE ALSO A
FEW AREAS OF ELEVATED SMOKE...ONE POTENTIALLY FROM FIRES IN THE
NORTHERN ROCKIES AND ANOTHER FROM CANADIAN FIRES. THERE HAVE BEEN
REPORTS OF PEOPLE SMELLING THE SMOKE AS WELL...SPECIFICALLY IN
NORTHERN WISCONSIN. HIGH TEMPERATURES WERE GENERALLY IN THE LOWER
80S THIS AFTERNOON...BUT WERE A BIT COOLER NEAR THE LAKE.
THE FOCUS FOR TONIGHT WILL BE ON THE CHANCE OF SHOWERS AND
THUNDERSTORMS. IT LOOKS LIKE COVERAGE WILL BE QUITE SPOTTY FOR THE
MOST PART. THE 4 KM NMM WRF ACTUALLY HAS VERY LITTLE IN THE WAY OF
FORECAST SURFACE REFLECTIVITY ACROSS THE AREA OVERNIGHT. THE
CHANCE OF STORMS WILL CONTINUE ON WEDNESDAY ACROSS MUCH OF THE CWA
AS A COLD FRONT/TROUGH DROPS ACROSS THE CWA. THE NAM ACTUALLY
HINTS AT A DECENT COMPLEX OF THUNDERSTORMS DEVELOPING ACROSS EC MN
AND NW WI DURING THE AFTERNOON BUT THE 4 KM NMM WRF SURFACE
REFLECTIVITY KEEPS PRECIPITATION ALONG THE INTERNATIONAL BORDER.
THE GFS IS SIMILAR TO THE NAM AS IS THE ECMWF. AS A RESULT...WE
FEEL THERE WILL BE AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS THAT AREA TOMORROW AFTERNOON AND
EVENING...BEFORE DIMINISHING FROM THE NW TO SE. TEMPS SHOULD SOAR
THROUGH THE 80S FOR MOST AREAS...AND HEAT INDEX VALUES ARE
EXPECTED TO BE ABOVE 90 IN AREAS OF THE SOUTH/SE.
LONG TERM...THURSDAY THROUGH TUESDAY...
FRONTAL BDRY WILL SLIDE SOUTH OF REGION THURSDAY WITH ONLY SLIGHT CHC
OF RW/TRW ACROSS ARROWHEAD AND SERN WISC ZONES. STRENGTHENING SFC
HIGH WILL MOVE INTO CTRL ONTARIO FRIDAY WITH WARM ADVECTION REGIME
INCREASING OVER CWA. POPS WILL SPREAD EAST AND INCREASE FRI/SAT AS
AN UPPER TROF/SFC LOW INTENSIFY ALONG INTERNATIONAL BORDER JUST WEST
OF CWA. HIGHEST POPS WOULD APPEAR TO BE FRI NIGHT AS MAIN MSTR
TRANSPORT AXIS SHIFTS ACROSS THE AREA. OCCLUDED FRONT WILL MOVE
ACROSS THE REGION SATURDAY...WITH THE UPPER TROF LAGGING BEHIND SFC
FEATURE . EXPECT RESIDUAL POPS AS CONVECTIVE INSTABILITY REMAINS
SUFFICIENT WITHIN A FAIRLY DEEP CYCLONIC CIRCULATION. GRADUAL
DECREASE IN PRECIP FROM WEST TO EAST SUNDAY AS SFC HIGH IS FINALLY
ALLOWED TO BUILD INTO THE REGION UNDERNEATH A PROGRESSIVE FLOW
ALOFT. SFC HIGH THEN SHIFTS EAST MONDAY WITH RETURN FLOW
DEVELOPING. AT THE SAME TIME...MID LVL RIDGE IS FCST TO AMPLIFY
OVERHEAD. DESPITE SOME INCREASE IN MSTR TRANSPORT HAVE COLLABORATED
WITH SURROUNDING OFFICES TO LEAVE POPS OUT OF FCST FOR NOW AS VERY
LARGE POOL OF MID LVL WARM AIR ADVECTS INTO CWA MAKING CONVECTIVE
POTENTIAL QUITE LIMITED. CURRENT FCST MAX TEMPS BASED ON CONSENSUS
BLEND OF NWP WITH HEAVIER WEIGHTING TO 0Z EC. LATEST EC
SIGNIFICANTLY WARMER SO SUSPECT NEXT UPDATE WILL INCREASE MAX TEMPS
MON AND ESPECIALLY TUESDAY.
&&
.POINT TEMPS/POPS...
DLH 65 86 63 81 / 30 40 30 10
INL 64 87 59 80 / 50 40 20 10
BRD 65 90 64 84 / 30 40 20 10
HYR 56 89 65 84 / 0 30 40 10
ASX 58 89 65 82 / 10 30 40 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...KK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
307 AM EDT WED AUG 1 2012
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE SOUTHEAST INTO THE
CAROLINAS THROUGH THURSDAY. UPPER LEVEL HIGH PRESSURE WILL THEN
BUILD INTO THE REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...
THIS MORNING...
COMPLICATED UPPER LEVEL FLOW CONTINUES OVER THE REGION WITH
NUMEROUS DISTURBANCES ROTATING THROUGH THE BASE OF THE UPPER LEVEL
TROUGH...WHICH CURRENTLY EXTENDS ALL THE WAY SOUTH INTO SOUTHERN
GA. THE MOST NOTABLE VORTICES WERE LOCATED OVER EASTERN
NC...UPSTATE SC...AND WESTERN VA. RECENT RADAR TRENDS SUGGEST THE
BROKEN LINE OF CONVECTION OVER VA WILL CONTINUE TO MOVE SLOWLY
EASTWARD AND THE OUTFLOW MAY BE THE FOCUS FOR SHOWERS OVER THE
NORTHERN COASTAL PLAIN DURING THE NEXT COUPLE OF HOURS. TO THE
SOUTH... SCATTERED SHOWERS AND A COUPLE THUNDERSTORMS ARE
EXPANDING NORTHWARD OUT OF SC INTO THE SOUTHERN PIEDMONT AND
SANDHILLS. A WEAK LOW PRESSURE CENTER IS FORECAST TO DEVELOP NEAR
THE SAVANNAH RIVER BASIN IN RESPONSE TO THE DPVA APPROACHING A
STALLED OUT...WEAK FRONTAL ZONE OVER THE SC/NC COASTAL REGIONS.
HOWEVER... IT IS HARD TO DETECT AN ACTUAL LOW SO FAR. 00Z RAOBS
FROM KMHX AND KCHS SHOW A FAIR AMOUNT OF ELEVATED INSTABILITY FOR
THE ONGOING SHOWERS TO FEED ON...AND THE HRRR SEEMS TO BE HANDLING
THE TIMING OF THE PRECIP WELL..ALTHOUGH THE RADAR ECHOES EXTEND
FURTHER WEST THAN THE SIMULATIONS. OVER THE NEXT 3-6
HOURS...SCATTERED TO NUMEROUS SHOWERS AND ISOLATED STORMS...ALONG
WITH MORE DEVELOPMENT BACK TO THE SOUTHWEST...SHOULD CONTINUE TO
MOVE TO THE NORTHEAST TO THE EAST OF US HWY 1...WITH MORE ISOLATED
SHOWERS POSSIBLE FURTHER WEST.
WHILE AN AXIS OF AROUND 1000 J/KG OF MUCAPE WILL EXIST THIS
MORNING...THE THREAT IF ANY SEVERE WEATHER IS LOW THROUGH MIDDAY
GIVEN THE WEAK DEEP LAYER FLOW IN THE TROUGH. IF/WHEN THE SURFACE
LOW DEVELOPS AND MOVES NORTHEAST ALONG THE COAST...THE MAY BE A
SHORT WINDOW WHERE LOW LEVEL SHEAR IS ENHANCED...BUT THE 0-1KM AND
0-3KM FLOW JUST LOOKS TOO WEAK FOR THE SMALL TORNADIC CONCERNS THAT
MODELS HAD SHOWN IN PREVIOUS RUNS.
THIS AFTERNOON...
AS THE AXIS OF DEEPER MOISTURE MOVES OFFSHORE...CONVECTION SHOULD
COME TO AN END OVER THE COASTAL PLAIN. ANOTHER UPPER DISTURBANCE
CURRENTLY OVER THE UPPER MIDWEST WILL DIVE INTO THE BACK SIDE OF
THE TROUGH THIS EVENING AND MAY KICK OFF SOME STORMS OVER THE
MOUNTAINS. HOWEVER...MUCH DRIER AIR ALOFT APPROACHING FROM THE
WEST...NOTED ON WATER VAPOR IMAGERY...SHOULD KEEP ANY STORMS
ISOLATED TO WIDELY SCATTERED OVER THE WESTERN PIEDMONT AND MAINLY
AFTER 20Z.
FULL HEATING WOULD SUPPORT HIGHS AROUND 90 TO THE WEST OF US HWY 1
THIS AFTERNOON. TO THE EAST...CLOUD COVER AND SHOWERS ARE GOING TO
LIMIT HEATING THIS MORNING...THOUGH THE EXPECTED DRYING ALOFT AND
THINNING OF CLOUDS FROM THE WEST SHOULD ALLOW MOST AREAS TO REACH
THE MID 80S.
TONIGHT...
OUTSIDE OF THE POTENTIAL FOR A FEW SHOWERS/STORMS MOVING
OFF THE HIGHER TERRAIN TO MAKE IT INTO THE PIEDMONT...CONDITIONS
SHOULD BE RELATIVELY QUIET WITH LOWS IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
THURSDAY AND THURSDAY NIGHT...
A WEAK UPPER LEVEL LOW/SHEAR AXIS IS FORECAST TO BREAK OFF FROM
THE UPPER TROUGH AND SLIP SOUTH TOWARD THE SC COAST ON THURSDAY.
THE FOCUS FOR CONVECTION WILL MAINLY BE ALONG THE COAST...WITH
WEAK ANTICYCLONIC FLOW AND DRIER AIR ALOFT OVER MUCH OF CENTRAL
NC. MAINLY A SLIGHT CHANCE OF SHOWERS/STORMS SOUTH AND EAST OF THE
TRIANGLE DURING THE AFTERNOON. LOW LEVEL THICKNESSES GENERALLY
SUPPORT LOWER 90S AREA WIDE. WITH LITTLE CLOUD COVER
OVERNIGHT...TEMPS SHOULD FALL QUICKLY TO THE UPPER 60S TO LOWER
70S...AND STRATUS/FOG MAY BE AN ISSUE.
FRIDAY AND FRIDAY NIGHT...
THE NAM AND THE GFS ARE FAIRLY CONSISTENT IN FORECASTING A WEAK
UPPER LOW OR SHEAR AXIS TOWARD THE COASTAL PLAIN AND THE CAROLINA
COAST. UNDER A BROAD SOUTHERLY FLOW FROM THE SURFACE THROUGH
850MB...MEAN MOISTURE GRADUALLY INCREASES...AND PRECIPITABLE WATER
VALUES THAT ARE AROUND 1.5 INCHES FRIDAY MORNING ARE FORECAST TO
INCREASE TO AROUND 1.75 INCHES BY 00Z SATURDAY. 250MB WINDS
DIMINISH AND WINDS FROM 850MB THROUGH 500MB ARE LIGHT... ONLY
AROUND 10KT AT BEST...MAKING FOR 0-6KM SHEAR VALUES ALSO AROUND
10KT AT BEST. WEAK LIFT IS FORECAST...BUT MUCH OF CENTRAL NORTH
CAROLINA MAY LIE JUST ON THE WEST SIDE OF THE UPPER LOW OR SHEAR
AXIS...AND NAM AND GFS BUFR SOUNDINGS SHOW A COUPLE OF DEGREES OF
MID- AND UPPER-LEVEL WARMING DURING THE DAY FRIDAY. WITH SLIGHT
MOISTURE ADVECTION...AND SOME UNCERTAINTY IN THE OVERALL LOCATION
OF THE WEAK UPPER-LEVEL FEATURES...THERE SHOULD BE ENOUGH
INSTABILITY... AROUND 1000J/KG OF MLCAPE...THAT A SEA BREEZE IN
THE SOUTHERLY FLOW...FOR EXAMPLE...COULD PROVIDE AN ISOLATED
SHOWER OR THUNDERSTORM. SLIGHT CHANCES WERE IN THE FORECAST AND
WILL NOT REMOVE THOSE...BUT CURRENTLY THINK THAT ISOLATED TO
WIDELY SCATTERED COVERAGE AT BEST WOULD OCCUR FRIDAY AFTERNOON
INTO FRIDAY EVENING.
BOTH THE NAM AND THE GFS PROVIDE FOR LIGHT QPF TOWARD AND WEST OF
THE YADKIN RIVER FRIDAY NIGHT...THOUGH BUFR SOUNDINGS WOULD TEND TO
SUPPORT MORE STABILITY AND THE TYPICAL DIURNAL MIN IN TERMS OF
CHANCES OF RAINFALL. THE GFS...AND TO SOME DEGREE THE NAM...FORECAST
A MODERATELY-STRONG MID-LEVEL SHORTWAVE MOVING INTO THE APPALACHIANS
LATE FRIDAY NIGHT...WHICH MAY BE A RESULT OF CONVECTIVE FEEDBACK.
THE SOUTHERLY 850MB FLOW IS FORECAST BY THE GFS TO STRENGTHEN NEAR
THE MOUNTAINS LATE FRIDAY NIGHT...SO AS THE AIR MASS MOISTENS IT IS
POSSIBLE FOR OVERNIGHT DEVELOPMENT OF SOME DEEP CONVECTION THERE...
THOUGH THE THERMAL WIND WOULD SEEM TO INDICATE A GENERAL MOTION
KEEPING MOST ACTIVITY WEST OF CENTRAL NORTH CAROLINA. WILL NOT
INTRODUCE ANY SLIGHT CHANCES FOR A SHOWER OR THUNDERSTORM OVERNIGHT
FRIDAY...THOUGH TRENDS WILL NEED TO BE WATCHED PARTICULARLY WITH
REGARD TO THE LOCATION AND STRENGTH OF ANY MID-LEVEL WAVE.
1000-850MB THICKNESSES SUPPORT THE SLIGHTLY COOLER MAV GUIDANCE FOR
HIGHS FRIDAY...MAINLY 90 TO 95. LOWS FRIDAY NIGHT AROUND 70.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THERE SEEM TO BE SOME CHANGES IN THE UPPER-AIR PATTERN AS
FORECAST BY THE GFS AND ECMWF...MOST NOTABLY HIGHER HEIGHTS ALOFT
OFFSHORE OF THE MID-ATLANTIC EARLY IN THIS PART OF THE LONG-TERM
PERIOD. AT THE SAME TIME...THE LOW-LEVEL FLOW AROUND BROAD BERMUDA
HIGH PRESSURE IS MORE SOUTHERLY ESPECIALLY EARLY IN THIS PART OF
THE LONG-TERM PERIOD...SUCH THAT THE MEAN AIR MASS IS GENERALLY
MORE MOIST THAN APPARENTLY WAS THE CASE AS FORECAST BY PREVIOUS
GUIDANCE. CERTAINLY THE TREND INTO EARLY NEXT WEEK
CONTINUES...WITH LOWERING HEIGHTS ALOFT AFTER THE WEEKEND AS AN
UPPER TROUGH MOVES EAST ACROSS THE GREAT LAKES AND SOUTHEAST
CANADA...EXTENDING INTO THE MID-ATLANTIC. BOTH THE GFS AND ECMWF
FORECAST A TROUGH AXIS ALOFT MOVING INTO CENTRAL NORTH CAROLINA
WITH A SHEAR AXIS LINGERING INTO TUESDAY. THE DGEX IS ALSO SIMILAR
IN REGARD TO THIS.
ANOTHER CONTINUING TREND OF THE CONSENSUS OF THE GFS AND ECMWF IS
THE GRADUAL INCREASE IN PRECIPITABLE WATER VALUES FROM SATURDAY
THROUGH MONDAY INTO TUESDAY. VALUES AROUND 1.75 INCHES OR SO
SATURDAY CLIMB TO AT OR JUST ABOVE TWO INCHES BY MONDAY AND
CONTINUE FOR THE MOST PART INTO TUESDAY...WITH POSSIBLY SOME
DRYING OVER THE NORTHWEST PIEDMONT LATE ON TUESDAY BASED ON THE
COARSE MODEL SOUNDINGS FROM THE GFS AND ECMWF. FOR THIS FORECAST...
MADE LITTLE CHANGES TO THE PREVIOUS FORECAST IN TERMS OF CHANCES FOR
PRECIPITATION...LOWER CHANCE PROBABILITIES FOR SATURDAY...GRADUALLY
INCREASING TO AROUND 40 PERCENT MONDAY WITH CHANCES CONTINUING
OVERNIGHT MONDAY NIGHT THROUGH TUESDAY NIGHT IN BETTER SYNOPTIC
FORCING ALOFT AS HEIGHTS FALL WITH THE ATTENDANT SHORTWAVE OR SHEAR
AXIS. THE HIGHEST CHANCES WILL BE FORECAST MONDAY...WHEN THERE
SHOULD BE THE BEST MID-LEVEL VORTICITY ADVECTION AND WHERE THE
GUIDANCE FORECASTS THE BEST LIFT. THE GFS HAS TRENDED SLIGHTLY
FASTER WITH THE TROUGH AXIS TUESDAY INTO TUESDAY NIGHT...AND FOR
THEN WILL NOTE HIGHER CHANCES...RELATIVE TO THE REST OF CENTRAL
NORTH CAROLINA...SOUTH AND EAST OF THE TRIAD. 1000-850MB THICKNESSES
HAVE TRENDED LOWER FROM RECENT DAYS IN THIS PART OF THE FORECAST...
AND WILL FORECAST HIGHS WITHIN A DEGREE OR THREE OF 90 SATURDAY
THROUGH MONDAY...THEN 85 TO 90 TUESDAY. OVERNIGHT LOWS WITHIN A
DEGREE OR THREE OF 70 EACH DAY...EXCEPT WARMER MONDAY NIGHT
ANTICIPATING MORE CLOUDS IN A VERY MOIST AIR MASS.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
AS OF 130 AM WEDNESDAY....
SHOWERS AND A COUPLE THUNDERSTORMS ARE BEGINNING TO EXPAND
NORTHEASTWARD ACROSS CENTRAL SC IN TO SOUTHERN NC. THIS AREA OF
PRECIP SHOULD CONTINUE TO MOVE NORTHEAST TOWARD KFAY OVER THE NEXT
HOUR OR TWO...AND CONTINUE THROUGH AT LEAST 12Z. A PERIOD OF
MVFR/IFR VSBYS AND CEILINGS CAN BE EXPECTED WITH THE HEAVIER
SHOWERS. ELSEWHERE...VFR CONDITIONS WILL GENERALLY PREVAIL THROUGH
THE 12Z...THOUGH CEILINGS AND VSBYS MAY LOWER TO MVFR AT KRDU AND
KRWI JUST PRIOR TO SUNRISE.
SHOWERS AND ISOLATED STORMS WILL SPREAD NORTHEAST THROUGH THE
COASTAL PLAIN DURING THE MORNING HOURS...MAINLY TO THE EAST OF KRWI
BASED ON THE MOST RECENT MODEL GUIDANCE. HOWEVER...IT IS POSSIBLE
THAT SHOWERS/STORMS MAY BE NEAR KRWI DURING THE 12-16Z TIME FRAME.
ONCE THIS ARE OF PRECIP MOVES OFF TO THE NORTHEAST BY LATE
MORNING...CONDITIONS ARE EXPECTED TO IMPROVE AT KRWI/KFAY/KRDU FOR
THE REMAINDER OFT HE TAF PERIOD. FURTHER WEST...SHOWERS AND STORMS
MAY DEVELOP ALONG THE MOUNTAINS AND PUSH EAST TOWARD KGSO/KINT LATE
TODAY...MOST LIKELY AFTER 20Z. HOWEVER....THERE IS LOW CONFIDENCE IN
EXACTLY IF OR WHEN EITHER TERMINAL COULD BE IMPACTED.
LOOKING AHEAD:
EXPECT A RELATIVELY TYPICAL SUMMER-TIME PATTERN CONSISTING OF
ISOLATED TO SCATTERED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS...AND A POTENTIAL FOR FOG/STRATUS DURING THE PRE-DAWN
HOURS (ROUGHLY 06-12Z) EACH DAY THROUGH THE REMAINDER OF THE WEEK
INTO THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/DJF
LONG TERM...DJF
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
107 AM EDT WED AUG 1 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCE THIS AFTERNOON INTO TONIGHT. COLD FRONT
MOVES THROUGH WEDNESDAY. HIGH PRESSURE WEDNESDAY NIGHT THROUGH
FRIDAY. COLD FRONT ARRIVES LATER SUNDAY AND SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
1030 PM UPDATE...SHOWERS/STORMS WINDING DOWN ACROSS THE FORECAST
AREA AS LACK OF REGENERATION ALLOWED ONGOING CONVECTION TO FINALLY
BEGIN MOVING OFF TO THE EAST. CURRENT SHOWERS OVER FAR EASTERN HIGH
TERRAIN WILL END OVER THE NEXT HOUR OR TWO. THOUGH MOST LOCATIONS
WILL REMAIN DRY...WILL CONTINUE A SLIGHT CHANCE OF RAIN SHOWERS
OVERNIGHT FOR MUCH OF THE AREA WITH BOTH THE RUC AND NAM DEPICTING
ANOTHER VORT MAX PUSHING SE-WARD ACROSS OHIO...WITH SOME LLVL
MOISTURE IN PLACE ALONG WITH EXISTING MESOSCALE OUTFLOW BOUNDARIES
FROM THIS EVENING/S STORMS.
PREVIOUS DISCUSSION...
NUMEROUS SHOWERS AND THUNDERSTORMS CURRENTLY DEPICTED BY RADAR
OVER NORTHERN WV MOUNTAINS...WITH MORE ISOLATED ACTIVITY SOUTHWARD
OVER THE MOUNTAINS. RAP SHOWS A VORT MAX ASSOCIATED WITH THIS
ACTIVITY...WHICH PUSHES OFF TO THE EAST THROUGH THE
AFTERNOON...WITH A SECOND VORT MAX MOVING IN FROM THE WEST. STILL
WAITING FOR SIGNS OF THE SECOND WAVE TO SHOW...AS AN OUTFLOW
BOUNDARY FROM EARLIER CONVECTION IN NORTHERN INDIANA ALSO MOVES
IN. VISIBLE SAT SHOWED SOME BUILDING CUMULUS CLOUDS IN PERRY
COUNTY...UP TOWARDS PBZ...ALONG THIS BOUNDARY BUT IT HAS BEEN
FAIRLY SLOW TO CONTINUE DEVELOPMENT. EXPECTING MORE DEVELOPMENT AS
THIS BOUNDARY PUSHES INTO CWA...WHERE THERE HAS BEEN A GOOD AMOUNT
OF HEATING SO FAR TODAY. INTERESTINGLY...THE WRFNMM SHOWS AN
OUTFLOW BOUNDARY COMING WEST OUT OF THE ACTIVITY NEAR
EKN...MEETING THE BOUNDARY APPROACHING FROM THE
NORTHEAST...DEVELOPING PRETTY ROBUST CONVECTION ALONG I-79. WILL
HAVE TO WAIT AND SEE JUST HOW THIS GOES...BUT AT ANY RATE...EXPECT
ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON. ISOLATED
SHOWERS AND STORMS MAY LINGER OVERNIGHT...WITH SCATTERED STORMS
AGAIN WEDNESDAY AS ANOTHER UPPER LEVEL SHORTWAVE TROUGH PASSES
THROUGH.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
MODELS SHOW A BRIEF LULL IN THE ACTIVE THUNDERSTORM PATTERN AS AN
UPPER LEVEL DISTURBANCE IN NORTHWEST FLOW ALOFT EXITS TO THE
SOUTHEAST AND ALLOWS WEAK HIGH PRESSURE TO BUILD IN FOR WEDNESDAY
NIGHT AND THURSDAY. THIS WILL ALLOW DRIER AIR TO OVERSPREAD THE
AREA...THOUGH TEMPERATURES THURSDAY WILL BE SIMILAR TO WEDNESDAY.
HOWEVER...WITH THE DRIER AIR...WEDNESDAY NIGHT WILL BE SOMEWHAT
COOLER THAN PREVIOUS NIGHTS. LOOK FOR TEMPERATURES TO REACH AROUND
90 DEGREES MANY LOW LAND LOCATIONS AGAIN THURSDAY...BUT LESS
HUMIDITY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HEIGHTS ONCE AGAIN BUILD IN FROM THE WEST BY FRIDAY WITH THE BERMUDA
HIGH STRENGTHENING...ALLOWING THE HEAT AND HUMIDITY TO MOVE BACK IN
FROM THE SOUTHWEST. CHANCES FOR STORMS INCREASE LATER FRIDAY AND
SATURDAY ON MORE OF A DIURNAL BASIS WITH THE INCREASING INSTABILITY.
THIS WILL ALSO BRING MORE HEAT BACK...WITH HIGH TEMPERATURES FRIDAY
AND SATURDAY REACHING INTO THE 90S AGAIN.
ANOTHER STRONGER NORTHWEST FLOW SYSTEM AND ATTENDING COLD FRONT DROP
SOUTHEASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THIS WILL
INCREASE CHANCES FOR STORMS SUNDAY AND SUNDAY NIGHT AHEAD OF THE
FRONT. MODELS ARE SOMEWHAT DIFFERENT IN TIMING OF THE SYSTEM...BUT
SUING THE SLOWER EURO AND GFS MODELS IN THIS HIGH SUMMER PATTERN LOOKS
REASONABLE. THIS WILL PUSH THE FRONT THROUGH MONDAY MORNING WITH
SHOWERS DECREASING FROM NORTHWEST TO SOUTHEAST ON MONDAY...FOLLOWED
BY SLIGHTLY COOLER TEMPS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
PATCHY DENSE FOG CAN BE EXPECTED EARLY THIS MORNING IN AREAS THAT
RECEIVED RAINFALL TODAY. A WEAK COLD FRONT WILL SLOWLY MOVE ACROSS
THE AREA TODAY. SHOWERS AND THUNDERSTORMS REMAIN A POSSIBILITY ALONG
AND EAST OF THE FRONT. AFTER THE FOG BURNS OFF BY MID MORNING...VFR
CONDITIONS WILL PREVAIL OUTSIDE OF SHOWERS AND THUNDERSTORMS. PATCHY
DENSE FOG IS POSSIBLE AGAIN LATE WEDNESDAY NIGHT...MORE LIKELY IN
THE MOUNTAIN VALLEYS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF SHOWERS AND THUNDERSTORMS COULD VARY.
TIMING AND DENSITY OF FOG COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 08/01/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H M M H H M H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L L H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY L L L L L L L L H H H H
AFTER 06Z THURSDAY...
IFR POSSIBLE IN DENSE FOG IN THE MOUNTAIN VALLEYS LATE WEDNESDAY
NIGHT AND THURSDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/MZ
NEAR TERM...MZ/50
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...RPY
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1040 AM EDT WED AUG 1 2012
.SYNOPSIS...
LOW PRESSURE OVER THE GULF OF MAINE THIS MORNING WILL MOVE OFF
THROUGH THE MARITIMES THIS AFTERNOON. A WEAKENING COLD FRONT WILL
BRING SHOWERS AND THUNDERSTORMS THIS AFTERNOON...ESPECIALLY TO
WESTERN NEW ENGLAND. WARMER AND MORE HUMID WEATHER IS EXPECTED FOR
THE MIDDLE AND END OF THE WEEK ALONG WITH A LOW CHANCE OF SHOWERS
AND THUNDERSTORMS EACH DAY LEADING UP TO MONDAY WHEN A COLD FRNT
SLIDES THRU NEW ENGLAND ALONG AND AHEAD OF WHICH A LINE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...
FOG/STRATUS HAS LIFTED AND IS MOVING OFF TO THE EAST. LINGERING
LATE MORNING CLOUDS ESPECIALLY OVER WESTERN AND CENTRAL
SECTIONS. CLEARING IS MOVING IN FROM THE WEST AND WAS REACHING
THE NY/MA BORDER BY 10 AM. BUT WATER VAPOR IMAGERY SHOWS MOIST AIR
OVER EASTERN NY AND WESTERN NEW ENGLAND...SO EXPECT ANY CLEARING
TO FILL IN WITH MORE CLOUDS THIS AFTERNOON.
STABILITY PARAMETERS ARE RATHER MARGINAL FOR THIS
AFTERNOON/EVENING. TOTALS CLIMB TO THE MID 40S...LI FALLS TO
AROUND -3...SURFACE BASED CAPE VALUES 500-800 J/KG. ALL OF THIS
POINTS TO SOME SUPPORT FOR SCATTERED TSTMS BUT QUESTIONABLE FOR
DAMAGING STORMS. PARAMETERS ARE MORE PRONOUNCED OVER EASTERN AND
CENTRAL NY/PA WITH TOTALS 50-52...LI OF -6...SBCAPE 1500-2000
J/KG...AND A THETA-E RIDGE FROM THE ADIRONDAKS TO CENTRAL PA.
PRECIPITABLE WATER VALUES ARE 1.5 TO 1.8 INCHES...SO ANY
SHOWERS/STORMS THAT FORM WOULD HAVE POTENTIAL FOR HEAVY DOWNPOURS.
STORM MOTION FROM THE 12Z ALB SOUNDING IS FROM THE WEST AT 11
KNOTS...WHICH WOULD MEAN THE HEAVY DOWNPOURS WOULD SLOWLY MOVE OUT
OF AN AREA. SO POTENTIAL FOR URBAN/POOR DRAINAGE FLOODING.
PUT IT ALL TOGETHER...HIGHEST POPS WEST AND LOWEST EAST THIS
AFTERNOON/EVENING WITH SHOWERS/TSTMS AND HEAVY DOWNPOURS.
TEMPS/DEWPOINTS GRIDS ARE ON TARGET SO NO CHANGES PLANNED TO THOSE
FORECASTS.
PREVIOUS DISCUSSION...
MAIN CONCERN FOR TODAY IS DEVELOPMENT OF SHOWERS/STORMS AS MID
LEVEL TROUGH AND WEAKENING COLD FRONT HEAD E FROM GREAT LAKES.
AIRMASS REMAINS UNSTABLE TO OUR W ACROSS PA WHERE STORMS HAVE
MAINTAINED THEMSELVES MOST OF THE NIGHT. 3KM HRRR BRINGS SOME OF
THIS WEAKENING ACTIVITY INTO WESTERN NEW ENGLAND AROUND 10 AM.
AFTER THAT DEVELOPMENT OF ADDITIONAL CONVECTION WILL DEPEND ON HOW
MUCH INSTABILITY CAN BE GENERATED. 00Z MODELS CONTINUE TO INDICATE
MORE FAVORABLE CONDITIONS WILL REMAIN TO OUR W THIS AFTERNOON...
BUT MARGINAL INSTABILITY COMBINED WITH WEAK CONVERGENCE ALONG
FRONT AND PLENTY OF LOW LEVEL MOISTURE SHOULD GENERATE MORE
SHOWERS AND STORMS ACROSS WESTERN NEW ENGLAND. SEVERE WEATHER
THREAT REMAINS LOW DUE TO WEAK MID LEVEL LAPSE RATES AND WEAK WIND
FIELDS ALOFT.
TOUGH CALL ON FORECAST HIGHS GIVEN UNCERTAINTY WITH CLOUD COVER
TODAY. LOWERED HIGHS SLIGHTLY WITH BLEND OF GFS/NAM MOS...IN 70S
TO MID 80S WITH WARMEST READINGS ACROSS INTERIOR EASTERN MA.
WEAK PRESSURE GRADIENT SHOULD ALLOW SEA BREEZES TO DEVELOP LATER
THIS MORNING. ALSO OF NOTE IS MODERATE RISK OF RIP CURRENTS WHICH
IS BEING FORECAST FOR CAPE COD AND ISLANDS AS WELL AS E MA COAST
TODAY. THIS IS DUE TO WIND WAVES OF 6-8 FT OFFSHORE TRANSITIONING
INTO E/SE SWELL.
&&
.SHORT TERM /THURSDAY/...
ANY CONVECTION SHOULD DIMINISH THIS EVENING ALBEIT SLOWLY AS
PLENTY OF LOW LEVEL MOISTURE REMAINS IN PLACE. EXPECT RETURN OF
PATCHY LOW CLOUDS AND FOG...ESPECIALLY NEAR COAST WITH LIGHT S/SW
FLOW.
CHANCES FOR SHOWERS/STORMS THU IS LOWER THAN TODAY DESPITE
CONTINUED PRESENCE OF MID LEVEL TROUGH. CROSS SECTIONS SHOW SOME
DRIER AIR WORKING IN ALOFT WHICH SHOULD LIMIT OVERALL CONVECTIVE
POTENTIAL. NONETHELESS WITH S/SW FLOW PROVIDING PLENTY OF LOW
LEVEL MOISTURE AND WEAK BOUNDARY NEARBY...INCLUDED ISOLATED
SHOWERS/STORMS ACROSS INTERIOR THU AFTERNOON. ONCE AGAIN SEVERE
THREAT IS VERY LOW.
ANOTHER LOW IS EXPECTED TO EMERGE OFF CAROLINAS BUT UPPER FLOW IS
PROGRESSIVE ENOUGH TO ALLOW THIS SYSTEM TO PASS WELL SE OF NEW
ENGLAND THU AFTERNOON.
NAM/GFS MOS CLOSE TONIGHT AND THU SO CONTINUED TO RUN WITH A BLEND
OF BOTH. SHOULD COME CLOSE TO 90 THU AFTERNOON IN PARTS OF PIONEER
AND MERRIMACK VALLEYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* HOT AND HUMID CONDITIONS FOR THE END OF THE WEEK INTO THE WEEKEND
* DIURNALLY DRIVEN STORMS PSBL FRIDAY AND SATURDAY
* QUIET WX FOR SUNDAY...COLD FRNT WITH SHOWERS AND THUNDERSTORMS MONDAY
* COOLER AND DRIER WX PSBL BEYOND MONDAY
MODEL DIAGNOSIS...
GENERAL AGREEMENT AMONGST FCST SOLNS CONTINUES TO BE EXHIBITED WITH
INITIAL 01/0Z MODEL GUIDANCE. ONLY SCRUTINY IS A SLIGHTLY FASTER H5
TROF DISTURBANCE ALONG THE US-CANADIAN BORDER AROUND 12Z SATURDAY...
YET BRIEFLY PER 01/0Z GFS WITH THE H5 TROF SLOWING IN ITS APPROACH
EWD AGAINST THE WRN ATLANTIC RIDGE INTO THE END OF THE WEEKEND. THIS
IS NOT SEEN THOUGH IN THE 01/0Z UKMET. AM LEFT TO CONSIDER GREATER
WEIGHT TOWARDS EUROPEAN FCST GUIDANCE...BUT WILL BLEND GFS/NAM FCST
GUIDANCE ACCORDINGLY.
THEREAFTER THERE IS SERIOUS DOUBT WITH THE 01/0Z GFS INVOKING A DEEP
CLOSED LOW ACROSS CENTRAL CANADA GOING AGAINST ITS RESPECTIVE 31/12Z
ENSEMBLE OUTPUT. YET THERE IS SOME UNCERTAINTY WITH THE 31/12Z ECMWF
USHERING THE SRN PLAINS/SRN ROCKIES H5 RIDGE EWD. GLOBAL ENSEMBLE
FCST GUIDANCE IN AGREEMENT OF A NEGATIVE NAO PATTERN FOR THE FIRST
WEEK OF AUGUST...BUT SOLNS BECOME DIVERSE AND THERE IS A LARGE AMNT
OF SPREAD BEYOND. AM EXPECTING A GENERAL TROF PATTERN FOR THE NERN
CONUS INTO THE EARLY PORTION OF NEXT WEEK WITH CONTINUED POS HEIGHT
ANOMALIES AND RIDGING OVER THE WRN ATLANTIC NWD INTO GREENLAND. AS
TO WHETHER THE TROF PATTERN CONTINUES...OR RATHER BREAKS DOWN...
AFTER THE FIRST WEEK OF AUGUST IS FAIRLY UNCERTAIN. AM NOT GIVING
MUCH CONSIDERATION TO THE FCST TUESDAY /7TH/ AND BEYOND.
THURSDAY NIGHT INTO FRIDAY NIGHT...
THE DEPARTURE OF THURS SYSTEM DRAWS WARM MOIST AIR NWD ALONG AND
AHEAD INVOKING POS HEIGHT RISES THRU THE WRN ATLANTIC AND
STRENGTHENING THE BERMUDA HIGH. SUBSEQUENTLY...W/SWLY FLOW IS
ENHANCED ACROSS NEW ENGLAND UNDER A MORE ZONAL FLOW REGIME THEREBY
DRAWING WARM AND MOIST AIR NEWD. MDL FCST SOUNDINGS EXHIBIT CAPPING
AROUND H85 WITH A FAIR AMNT OF ELEVATED INSTABILITY. THERE ARE
SUBTLE HINTS OF WEAK ENERGY ADVECTING THRU THE ZONAL FLOW REGIME
DURING THE DAY FRIDAY...AND WITH THAT BEING SAID THERE IS THE
PLAUSIBILITY OF CONVECTION FORCED VIA CYCLONIC FLOW AND ENHANCED
ASCENT THRU THE CAPPING INVERSION. HEAVY RAIN WILL REMAIN A THREAT
WITH PWAT VALUES AROUND 1.5 INCHES. FEEL ANY CONVECTION WILL BE
ISOLATED /GREATER CHCS ACROSS THE INTERIOR/. AM NOT THINKING
ANYTHING SEVERE. LOOKING AT A VERY HOT AND HUMID DAY FRIDAY.
SATURDAY INTO SATURDAY NIGHT...
FCST GUIDANCE SUGGESTS AN ATTENDANT WEAK WARM FRNTL BOUNDARY PARENT
WITH THE SFC LOW AND H5 TROF ACROSS THE GRT LKS WILL BE THE FOCUS
FOR DIURNALLY FORCED CONVECTION. CAPPING INVERSION AROUND H85 IS
STILL APPARENT AND A STRENGTHENING BERMUDA HIGH TOWARDS THE ERN
CONUS RESULTS IN THE INTRUSION OF DRIER AIR THRU THE MID-LVLS. YET
HEIGHT FALLS ARE EXPECTED ACROSS THE WRN INTERIOR WITH THE APPROACH
OF THE H5 TROF AXIS...AND SHOULD SOME SFC CONVERGENCE PREVAIL ALONG
THE WEAK WARM FRNTL BOUNDARY...FEEL THE WRN INTERIOR WILL HAVE CHC
FOR SHOWERS AND THUNDERSTORMS. NOT COMPLETELY SOLD ON THE OUTCOME...
ITS PSBL THE PERIOD MAY TURN OUT DRY. IF ANY POPS...SLGT CHC. HOT
AND HUMID CONDITIONS CONTINUE FOR THE INTERIOR...COOLER NEAR THE
SHORES.
SUNDAY INTO MONDAY...
SUNDAY APPEARS THE BETTER OF THE TWO DAYS WITH THE RGN FINDING
ITSELF WITHIN THE WARM SECTOR AHEAD OF THE APPROACHING TROF AXIS AND
ATTENDANT COLD FRNT. ANY FORCING MAY BE WELL N OF THE FCST AREA.
OTHERWISE THE MAIN SHOW PREVAILS FOR MONDAY AS A COLD FRNT WITH
SHOWERS AND THUNDERSTORMS SWEEPS THRU THE RGN. AM VERY CONCERNED
WITH THE POSSIBILITY OF HEAVY RAIN AND FLASH FLOODING AS PWATS ARE
ADVERTISED AROUND 2 INCHES /IN SOME CASES 2.5/. NOT CERTAIN STORMS
WILL BE SEVERE /PARAMETERS OF SHEAR APPEAR WEAK WITH MODEST
INSTABILITY THOUGH SKINNY AND THIN THRU THE ATMOS COLUMN/.
TUESDAY AND BEYOND...
WILL PREVAIL A DRY FCST FOR NOW. AS NOTED BY THE PREV FORECASTER...
THE STRONGER WRN ATLANTIC RIDGE MAY SLOW THE PROGRESSION OF THE COLD
FRNT ON MONDAY THEREBY RESULTING IN ACTIVE WX TO LINGER INTO TUE. AS
IT STANDS PRESENTLY...FCST GUIDANCE IS QUICK TO MOVE THE SYS
OFFSHORE AND USHER ACROSS THE RGN COOLER AND DRIER HIGH PRES. WILL
PREVAIL AS SUCH.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THIS AFTERNOON THROUGH THURSDAY...MODERATE CONFIDENCE.
LINGERING 1000-2000 FOOT CEILINGS AROUND SOUTHERN NEW ENGLAND LATE
MORNING SHOULD SCATTER OUT THIS AFTERNOON. EXPECT VFR CEILINGS
THIS AFTERNOON WITH SHOWERS/TSTMS DEVELOPING THIS AFTERNOON. BEST
CHANCE FOR THIS WILL BE IN THE CT VALLEY AND EAST SLOPES OF THE
BERKSHIRES...LOWEST CHANCE WOULD BE ALONG THE MASS EAST COAST.
PSBL LOW CIGS AND VSBYS WILL RETURN TONIGHT /BETTER CHCS ALONG
THE IMMEDIATE COAST/. WILL ALLOW LATER SHIFTS TO INTERPRET WITH
FUTURE SETS OF TAFS...DID NOT PREVAIL DUE TO LOW CONFIDENCE.
EXPECT VFR FOR THURS WITH PSBL ISOLATED STORMS BY THE AFTN HRS
MAINLY ACROSS INTERIOR TERMINALS.
KBOS TAF...MODERATE CONFIDENCE.
VFR WITH DEVELOPING SEA BREEZE MIDDAY. POTENTIAL FOR AN HOUR OR
TWO OF 1500 FOOT CEILINGS AROUND MIDDAY. SHOWERS/TSTMS DEVELOPING
NORTH AND WEST OF THE AIRPORT BUT WILL LIKELY STAY NORTH AND WEST
THROUGH EVENING. VFR TONIGHT WITH POTENTIAL FOR MVFR VSBY IN FOG.
VFR THURSDAY WITH ISOLATED TSTMS AND BRIEF MVFR CIGS/VSBYS.
KBDL TAF...MODERATE CONFIDENCE.
VFR CIGS/VSBYS BUT WITH POTENTIAL FOR AN HOUR OR TWO OF MVFR
MIDDAY. SHOWERS/TSTMS DEVELOP THIS AFTERNOON WITH BRIEF MVFR/IFR
IN ANY PCPN. ANY STORMS SHOULD BE SLOW MOVING...AND SO LOCALLY
HEAVY DOWNPOURS ARE POSSIBLE WITH IFR CONDITIONS. VFR TONIGHT WITH
MVFR VSBYS IN PATCHY FOG LATE AT NIGHT. VFR THURSDAY WITH ISOLATED
TSTMS AND BRIEF MVFR CIGS/VSBYS.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY NIGHT...
PSBL CONVECTION FRI ACROSS THE INTERIOR...LOW CONFIDENCE. OTHERWISE
PREVAIL VFR WITH MODEST W/SWLY FLOW. GUSTS OVER SHORELINE TERMINALS
AROUND 20 KTS.
SATURDAY INTO SATURDAY NIGHT...
RENEWED CHCS FOR SHRA/TSRA ACROSS THE INTERIOR...LOW CONFIDENCE. SLY
FLOW WITH GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
COLD FRNT APPROACHES WITH SHRA/TSRA ALONG AND AHEAD. SUNDAY VFR WITH
INCREASING SLY FLOW /GUSTS AROUND 20 KTS/. SHOULD REMAIN DRY.
MONDAY...SHRA/TSRA EXPECTED CLEARING LATE INTO TUE MORN.
&&
.MARINE...
SCA REMAINS POSTED INTO AFTERNOON FOR THE EASTERN OUTER WATERS AS
WINDS AND SEAS CONTINUE TO DIMINISH.
WEAKER WINDS THIS AFTERNOON AS SURFACE LOW HEADS OUT TO SEA.
AFTERNOON SEA BREEZES EXPECTED. S/SW FLOW PREVAILS TONIGHT AND
THU WITH PATCHY LATE NIGHT AND EARLY MORNING FOG.
LOW PRESSURE SHOULD PASS WELL S AND E OF NEW ENGLAND THU BUT WE
MAY SEE SEAS OF 5-6 FT REACH OUTER WATERS.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY NIGHT...
W/SWLY FLOW BECOMING SLY WITH GUSTS AROUND 20 KTS FOR THE S WATERS
WILL INVOKE SEAS OF 5 FT ALL THE WAY INTO THE LOCAL SOUNDS AND BAYS.
NOT EXPECTING ANY STORMS.
SATURDAY INTO SATURDAY NIGHT...
SLY FLOW WILL REMAIN BRISK BUT WEAKER ENOUGH TO ALLOW SWELL TO
DIMINISH. GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
SLY FLOW INCREASING INTO SUNDAY IN RESPONSE TO APPROACHING COLD
FRNT. SEAS BUILDING ALONG THE S AND E WATERS IN RESPONSE. COLD FRNT
TO SLIDE ACROSS THE WATERS LATE MONDAY ALONG AND AHEAD OF WHICH
SHOWERS AND THUNDERSTORMS ARE EXPECTED AND LIKELY TO LINGER INTO THE
TUE MORN HRS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ250-
254-255.
&&
$$
SYNOPSIS...SIPPRELL/JWD
NEAR TERM...WTB/SIPPRELL/JWD
SHORT TERM...JWD
LONG TERM...SIPPRELL
AVIATION...SIPPRELL/JWD
MARINE...SIPPRELL/JWD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
712 AM EDT WED AUG 1 2012
.SYNOPSIS...
LOW PRESSURE OVER THE GULF OF MAINE THIS MORNING WILL HEAD FARTHER
OUT TO SEA TODAY. A WEAKENING COLD FRONT WILL BRING SHOWERS AND
THUNDERSTORMS THIS AFTERNOON...ESPECIALLY TO WESTERN NEW ENGLAND.
WARMER AND MORE HUMID WEATHER IS EXPECTED FOR THE MIDDLE AND END
OF THE WEEK ALONG WITH A LOW CHANCE OF SHOWERS AND THUNDERSTORMS
EACH DAY LEADING UP TO MONDAY WHEN A COLD FRNT SLIDES THRU NEW
ENGLAND ALONG AND AHEAD OF WHICH A LINE OF SHOWERS AND
THUNDERSTORMS IS EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
7 AM UPDATE...
CLUSTER OF SHOWERS MOVING THRU THE NYC METRO LIKELY A RESULT OF
A LOCALIZED LOW-LVL JET ABOVE THE SFC INVERSION AND BELOW A
SHALLOW RGN /AROUND H7/ OF STEEP LAPSE RATES AND ELEVATED
INSTABILITY. VERY LITTLE IF ANY LIGHTNING ASSOCIATED WITH THE
CLUSTER AGREEING WITH FCST MDL SOUNDINGS HIGHLIGHTING MUCH OF THE
ELEVATED INSTABILITY BELOW THE FRZG MARK /AND MORE IMPORTANTLY
-10C/. ENERGY IS GRADUALLY FIZZLING...BUT IT IS PLAUSIBLE TO SEE
SOME OF THAT ENERGY IMPACT THE LOWER CT VLY BY 13-14Z.
OTHERWISE EXPECTING ADDITIONAL ENERGY TO BLOSSOM UPSTREAM ALONG
AND AHEAD OF THE SFC COLD FRNT PRESENTLY ACROSS THE ERN GRT LKS...
BETTER CHCS FOR SHOWERS AND THUNDERSTORMS WILL ERUPT AS THE SUN
RISES AND QUICKLY MIXES OUT THE BOUNDARY LYR /FOG AND LOW STRATUS
TO SUBSEQUENTLY DISSIPATE/. PER MDL FCST SOUNDINGS...INSTABILITY
IS THIN AND ELONGATED THRU THE ATMOS COLUMN...A MAJORITY OF WHICH
IS BELOW THE BETTER FRZG LVLS. AM IN BELIEF THAT ANY CONVECTION
WILL BE ISOLATED TO SCATTERED AND SUB-SEVERE. PWATS ARE HIGH
/AROUND 1.75 INCHES/ SO THERE IS THE THREAT FOR HEAVY DOWNPOURS
AND LOCALIZED FLOODING WITH ANY STORMS.
PREVIOUS DISCUSSION...
MAIN CONCERN FOR TODAY IS DEVELOPMENT OF SHOWERS/STORMS AS MID
LEVEL TROUGH AND WEAKENING COLD FRONT HEAD E FROM GREAT LAKES.
AIRMASS REMAINS UNSTABLE TO OUR W ACROSS PA WHERE STORMS HAVE
MAINTAINED THEMSELVES MOST OF THE NIGHT. 3KM HRRR BRINGS SOME OF
THIS WEAKENING ACTIVITY INTO WESTERN NEW ENGLAND AROUND 10 AM.
AFTER THAT DEVELOPMENT OF ADDITIONAL CONVECTION WILL DEPEND ON HOW
MUCH INSTABILITY CAN BE GENERATED. 00Z MODELS CONTINUE TO INDICATE
MORE FAVORABLE CONDITIONS WILL REMAIN TO OUR W THIS AFTERNOON...
BUT MARGINAL INSTABILITY COMBINED WITH WEAK CONVERGENCE ALONG
FRONT AND PLENTY OF LOW LEVEL MOISTURE SHOULD GENERATE MORE
SHOWERS AND STORMS ACROSS WESTERN NEW ENGLAND. SEVERE WEATHER
THREAT REMAINS LOW DUE TO WEAK MID LEVEL LAPSE RATES AND WEAK WIND
FIELDS ALOFT.
TOUGH CALL ON FORECAST HIGHS GIVEN UNCERTAINTY WITH CLOUD COVER
TODAY. LOWERED HIGHS SLIGHTLY WITH BLEND OF GFS/NAM MOS...IN 70S
TO MID 80S WITH WARMEST READINGS ACROSS INTERIOR EASTERN MA.
WEAK PRESSURE GRADIENT SHOULD ALLOW SEA BREEZES TO DEVELOP LATER
THIS MORNING. ALSO OF NOTE IS MODERATE RISK OF RIP CURRENTS WHICH
IS BEING FORECAST FOR CAPE COD AND ISLANDS AS WELL AS E MA COAST
TODAY. THIS IS DUE TO WIND WAVES OF 6-8 FT OFFSHORE TRANSITIONING
INTO E/SE SWELL.
&&
.SHORT TERM /THURSDAY/...
ANY CONVECTION SHOULD DIMINISH THIS EVENING ALBEIT SLOWLY AS
PLENTY OF LOW LEVEL MOISTURE REMAINS IN PLACE. EXPECT RETURN OF
PATCHY LOW CLOUDS AND FOG...ESPECIALLY NEAR COAST WITH LIGHT S/SW
FLOW.
CHANCES FOR SHOWERS/STORMS THU IS LOWER THAN TODAY DESPITE
CONTINUED PRESENCE OF MID LEVEL TROUGH. CROSS SECTIONS SHOW SOME
DRIER AIR WORKING IN ALOFT WHICH SHOULD LIMIT OVERALL CONVECTIVE
POTENTIAL. NONETHELESS WITH S/SW FLOW PROVIDING PLENTY OF LOW
LEVEL MOISTURE AND WEAK BOUNDARY NEARBY...INCLUDED ISOLATED
SHOWERS/STORMS ACROSS INTERIOR THU AFTERNOON. ONCE AGAIN SEVERE
THREAT IS VERY LOW.
ANOTHER LOW IS EXPECTED TO EMERGE OFF CAROLINAS BUT UPPER FLOW IS
PROGRESSIVE ENOUGH TO ALLOW THIS SYSTEM TO PASS WELL SE OF NEW
ENGLAND THU AFTERNOON.
NAM/GFS MOS CLOSE TONIGHT AND THU SO CONTINUED TO RUN WITH A BLEND
OF BOTH. SHOULD COME CLOSE TO 90 THU AFTERNOON IN PARTS OF PIONEER
AND MERRIMACK VALLEYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* HOT AND HUMID CONDITIONS FOR THE END OF THE WEEK INTO THE WEEKEND
* DIURNALLY DRIVEN STORMS PSBL FRIDAY AND SATURDAY
* QUIET WX FOR SUNDAY...COLD FRNT WITH SHOWERS AND THUNDERSTORMS MONDAY
* COOLER AND DRIER WX PSBL BEYOND MONDAY
MODEL DIAGNOSIS...
GENERAL AGREEMENT AMONGST FCST SOLNS CONTINUES TO BE EXHIBITED WITH
INITIAL 01/0Z MODEL GUIDANCE. ONLY SCRUTINY IS A SLIGHTLY FASTER H5
TROF DISTURBANCE ALONG THE US-CANADIAN BORDER AROUND 12Z SATURDAY...
YET BRIEFLY PER 01/0Z GFS WITH THE H5 TROF SLOWING IN ITS APPROACH
EWD AGAINST THE WRN ATLANTIC RIDGE INTO THE END OF THE WEEKEND. THIS
IS NOT SEEN THOUGH IN THE 01/0Z UKMET. AM LEFT TO CONSIDER GREATER
WEIGHT TOWARDS EUROPEAN FCST GUIDANCE...BUT WILL BLEND GFS/NAM FCST
GUIDANCE ACCORDINGLY.
THEREAFTER THERE IS SERIOUS DOUBT WITH THE 01/0Z GFS INVOKING A DEEP
CLOSED LOW ACROSS CENTRAL CANADA GOING AGAINST ITS RESPECTIVE 31/12Z
ENSEMBLE OUTPUT. YET THERE IS SOME UNCERTAINTY WITH THE 31/12Z ECMWF
USHERING THE SRN PLAINS/SRN ROCKIES H5 RIDGE EWD. GLOBAL ENSEMBLE
FCST GUIDANCE IN AGREEMENT OF A NEGATIVE NAO PATTERN FOR THE FIRST
WEEK OF AUGUST...BUT SOLNS BECOME DIVERSE AND THERE IS A LARGE AMNT
OF SPREAD BEYOND. AM EXPECTING A GENERAL TROF PATTERN FOR THE NERN
CONUS INTO THE EARLY PORTION OF NEXT WEEK WITH CONTINUED POS HEIGHT
ANOMALIES AND RIDGING OVER THE WRN ATLANTIC NWD INTO GREENLAND. AS
TO WHETHER THE TROF PATTERN CONTINUES...OR RATHER BREAKS DOWN...
AFTER THE FIRST WEEK OF AUGUST IS FAIRLY UNCERTAIN. AM NOT GIVING
MUCH CONSIDERATION TO THE FCST TUESDAY /7TH/ AND BEYOND.
THURSDAY NIGHT INTO FRIDAY NIGHT...
THE DEPARTURE OF THURS SYSTEM DRAWS WARM MOIST AIR NWD ALONG AND
AHEAD INVOKING POS HEIGHT RISES THRU THE WRN ATLANTIC AND
STRENGTHENING THE BERMUDA HIGH. SUBSEQUENTLY...W/SWLY FLOW IS
ENHANCED ACROSS NEW ENGLAND UNDER A MORE ZONAL FLOW REGIME THEREBY
DRAWING WARM AND MOIST AIR NEWD. MDL FCST SOUNDINGS EXHIBIT CAPPING
AROUND H85 WITH A FAIR AMNT OF ELEVATED INSTABILITY. THERE ARE
SUBTLE HINTS OF WEAK ENERGY ADVECTING THRU THE ZONAL FLOW REGIME
DURING THE DAY FRIDAY...AND WITH THAT BEING SAID THERE IS THE
PLAUSIBILITY OF CONVECTION FORCED VIA CYCLONIC FLOW AND ENHANCED
ASCENT THRU THE CAPPING INVERSION. HEAVY RAIN WILL REMAIN A THREAT
WITH PWAT VALUES AROUND 1.5 INCHES. FEEL ANY CONVECTION WILL BE
ISOLATED /GREATER CHCS ACROSS THE INTERIOR/. AM NOT THINKING
ANYTHING SEVERE. LOOKING AT A VERY HOT AND HUMID DAY FRIDAY.
SATURDAY INTO SATURDAY NIGHT...
FCST GUIDANCE SUGGESTS AN ATTENDANT WEAK WARM FRNTL BOUNDARY PARENT
WITH THE SFC LOW AND H5 TROF ACROSS THE GRT LKS WILL BE THE FOCUS
FOR DIURNALLY FORCED CONVECTION. CAPPING INVERSION AROUND H85 IS
STILL APPARENT AND A STRENGTHENING BERMUDA HIGH TOWARDS THE ERN
CONUS RESULTS IN THE INTRUSION OF DRIER AIR THRU THE MID-LVLS. YET
HEIGHT FALLS ARE EXPECTED ACROSS THE WRN INTERIOR WITH THE APPROACH
OF THE H5 TROF AXIS...AND SHOULD SOME SFC CONVERGENCE PREVAIL ALONG
THE WEAK WARM FRNTL BOUNDARY...FEEL THE WRN INTERIOR WILL HAVE CHC
FOR SHOWERS AND THUNDERSTORMS. NOT COMPLETELY SOLD ON THE OUTCOME...
ITS PSBL THE PERIOD MAY TURN OUT DRY. IF ANY POPS...SLGT CHC. HOT
AND HUMID CONDITIONS CONTINUE FOR THE INTERIOR...COOLER NEAR THE
SHORES.
SUNDAY INTO MONDAY...
SUNDAY APPEARS THE BETTER OF THE TWO DAYS WITH THE RGN FINDING
ITSELF WITHIN THE WARM SECTOR AHEAD OF THE APPROACHING TROF AXIS AND
ATTENDANT COLD FRNT. ANY FORCING MAY BE WELL N OF THE FCST AREA.
OTHERWISE THE MAIN SHOW PREVAILS FOR MONDAY AS A COLD FRNT WITH
SHOWERS AND THUNDERSTORMS SWEEPS THRU THE RGN. AM VERY CONCERNED
WITH THE POSSIBILITY OF HEAVY RAIN AND FLASH FLOODING AS PWATS ARE
ADVERTISED AROUND 2 INCHES /IN SOME CASES 2.5/. NOT CERTAIN STORMS
WILL BE SEVERE /PARAMETERS OF SHEAR APPEAR WEAK WITH MODEST
INSTABILITY THOUGH SKINNY AND THIN THRU THE ATMOS COLUMN/.
TUESDAY AND BEYOND...
WILL PREVAIL A DRY FCST FOR NOW. AS NOTED BY THE PREV FORECASTER...
THE STRONGER WRN ATLANTIC RIDGE MAY SLOW THE PROGRESSION OF THE COLD
FRNT ON MONDAY THEREBY RESULTING IN ACTIVE WX TO LINGER INTO TUE. AS
IT STANDS PRESENTLY...FCST GUIDANCE IS QUICK TO MOVE THE SYS
OFFSHORE AND USHER ACROSS THE RGN COOLER AND DRIER HIGH PRES. WILL
PREVAIL AS SUCH.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE CONFIDENCE.
AM ANTICIPATING CONDITIONS TO GRADUALLY IMPROVE TO VFR INTO THE
MID-MORNING HRS WITH THE INCREASE OF SHRA AND PSBL TSRA INTO THE
MIDDAY AND AFTN HRS. LOW CONFIDENCE WITH TSRA SO REMOVED FROM TAF.
FEEL TSRA CHCS WILL BE ISOLATED TO SCT. ANY SHRA/TSRA IMPACTS WILL
LIKELY RESULT IN MVFR-IFR VSBY IMPACTS /PSBL MVFR CIGS BUT WILL
PREVAIL VFR/. LESSER CHANCE OF TSTMS E OF MHT-ORH-IJD. PSBL LOW
CIGS AND VSBYS WILL RETURN TONIGHT /BETTER CHCS ALONG THE
IMMEDIATE COAST/. WILL ALLOW LATER SHIFTS TO INTERPRET WITH FUTURE
SETS OF TAFS...DID NOT PREVAIL DUE TO LOW CONFIDENCE. EXPECT VFR
FOR THURS WITH PSBL ISOLATED STORMS BY THE AFTN HRS MAINLY ACROSS
INTERIOR TERMINALS.
KBOS TAF...MODERATE CONFIDENCE.
IFR TO GRADUALLY LIFT INTO MORNING BY WHICH TIME HEATING OF THE
DAY MAY PROMOTE A SEA-BREEZE AROUND 16Z. AM NOT CONFIDENT AFTN
SHRA WILL IMPACT THE TERMINAL BUT WILL WATCH CLOSELY.
KBDL TAF...MODERATE CONFIDENCE.
MVFR CIGS TO GRADUALLY LIFT ALLOWING FOR THE DEVELOPMENT OF SHRA
AND PSBL TSRA INTO THE MIDDAY TO AFTN PD. SHOULD ANY STORMS IMPACT
THE TERMINAL...MVFR-IFR VSBYS PSBL.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY NIGHT...
PSBL CONVECTION FRI ACROSS THE INTERIOR...LOW CONFIDENCE. OTHERWISE
PREVAIL VFR WITH MODEST W/SWLY FLOW. GUSTS OVER SHORELINE TERMINALS
AROUND 20 KTS.
SATURDAY INTO SATURDAY NIGHT...
RENEWED CHCS FOR SHRA/TSRA ACROSS THE INTERIOR...LOW CONFIDENCE. SLY
FLOW WITH GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
COLD FRNT APPROACHES WITH SHRA/TSRA ALONG AND AHEAD. SUNDAY VFR WITH
INCREASING SLY FLOW /GUSTS AROUND 20 KTS/. SHOULD REMAIN DRY.
MONDAY...SHRA/TSRA EXPECTED CLEARING LATE INTO TUE MORN.
&&
.MARINE...
SCA REMAINS POSTED INTO AFTERNOON FOR OUTER WATERS AS WINDS AND
SEAS CONTINUE TO DIMINISH.
WEAKER GRADIENT TODAY AS SURFACE LOW HEADS OUT TO SEA WITH
AFTERNOON SEA BREEZES EXPECTED. S/SW FLOW PREVAILS TONIGHT AND THU
WITH PATCHY LATE NIGHT AND EARLY MORNING FOG.
LOW PRESSURE SHOULD PASS WELL S AND E OF NEW ENGLAND THU BUT WE
MAY SEE SEAS OF 5-6 FT REACH OUTER WATERS.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY NIGHT...
W/SWLY FLOW BECOMING SLY WITH GUSTS AROUND 20 KTS FOR THE S WATERS
WILL INVOKE SEAS OF 5 FT ALL THE WAY INTO THE LOCAL SOUNDS AND BAYS.
NOT EXPECTING ANY STORMS.
SATURDAY INTO SATURDAY NIGHT...
SLY FLOW WILL REMAIN BRISK BUT WEAKER ENOUGH TO ALLOW SWELL TO
DIMINISH. GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
SLY FLOW INCREASING INTO SUNDAY IN RESPONSE TO APPROACHING COLD
FRNT. SEAS BUILDING ALONG THE S AND E WATERS IN RESPONSE. COLD FRNT
TO SLIDE ACROSS THE WATERS LATE MONDAY ALONG AND AHEAD OF WHICH
SHOWERS AND THUNDERSTORMS ARE EXPECTED AND LIKELY TO LINGER INTO THE
TUE MORN HRS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ250-
254-255.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ256.
&&
$$
SYNOPSIS...SIPPRELL/JWD
NEAR TERM...SIPPRELL/JWD
SHORT TERM...JWD
LONG TERM...SIPPRELL
AVIATION...SIPPRELL/JWD
MARINE...SIPPRELL/JWD
AREA FORECAST DISCUSSION
NWS JACKSON KY
1057 AM EDT WED AUG 1 2012
.UPDATE...
ISSUED AT 1057 AM EDT WED AUG 1 2012
MORNING CONVECTION DIMINISHED BETWEEN 9 AND 10 AM...AS SCHEDULED.
TEMPERATURES CAME IN COOLER THIS MORNING COMPARED TO TUESDAY
MORNING...AND THIS HAS HAMPERED THE DIURNAL RISE SO FAR. HAVE LOWERED
THE HIGHS A TOUCH TO ACCOUNT FOR THIS TREND...BUT GENERALLY MOST
LOCATIONS WILL STILL SEE AROUND 90. A WEAK STATIONARY FRONT REMAINS
DRAPED FROM JUST SOUTH OF A LINE FROM KEVV...TO KSDF...TO KILN.
ANOTHER SHORT WAVE TROUGH...CURRENTLY MOVING SOUTHEAST ACROSS INDIANA
WILL ALSO MOVE INTO EASTERN KENTUCKY THIS AFTERNOON. GIVEN THESE TWO
FEATURES...HAVE GONE AHEAD AND INCLUDED SLIGHT CHANCE POPS FOR ALL.
THE HRRR HAS BEEN GENERATING SOME CONVECTION ACROSS MOST OF THE
AREA...ALTHOUGH THE 06 AND 12Z NAM RUNS HAVE REMAINED DRY. THE
FORECAST SOUNDINGS HAVE TRENDED A BIT WEAKER WITH THE CAP THIS
AFTERNOON...AND THERE IS PLENTY OF DRY AIR ALOFT...WITH MUCH LOWER
WET-BULB ZERO HEIGHTS TODAY. WILL HAVE TO WATCH FOR A FEW PULSERS
THAT CAN TAKE ADVANTAGE OF THIS ENVIRONMENT.
UPDATE ISSUED AT 750 AM EDT WED AUG 1 2012
UPDATED THE GRIDS...MINORLY...TO BETTER REFLECT POPS EARLY THIS
MORNING. ALSO TWEAKED SKY...T AND TD GRIDS FOR CURRENT OBS AND
TRENDS. UPDATES HAVE BEEN SENT TO NDFD AND THE WEB.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 335 AM EDT WED AUG 1 2012
06Z SFC ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE LAYING ACROSS THE
NORTHWEST PORTION OF EASTERN KENTUCKY...RELATED TO A MINOR COLD FRONT
THAT IS PASSING THROUGH THE AREA EARLY THIS MORNING. THIS HAS JUST
RECENTLY HELPED TO TRIGGER A FEW CELLS OF CONVECTION IN THE WESTERN
PARTS OF THE CUMBERLAND VALLEY...DRIFTING SOUTHEAST INTO THE
SOUTHERN INTERSTATE 75 CORRIDOR. ON SATELLITE...THE CLOUDS HAVE
INCREASED DURING THE PAST COUPLE OF HOURS IN RESPONSE TO THE
BOUNDARY AND SOME ENERGY PASSING THROUGH AT MID LEVELS. THE CLOUDS
WILL HELP TO LIMIT ANY FURTHER DROP IN TEMPERATURES THROUGH THE REST
OF THE NIGHT. AS IT STANDS...A MINOR RIDGE TO VALLEY TEMPERATURE
SPLIT ON THE ORDER OF ABOUT 5 DEGREES EXISTS OUT THERE...MAINLY IN
THE NORTHEAST AS OF 3 AM EDT. LOW DEWPOINT DEPRESSIONS ARE ALSO
FOUND IN THE VALLEYS AND ANY PLACE THAT MANAGE TO STAY MOSTLY CLEAR
CAN EXPECT PATCHY FOG IN THE VALLEYS TOWARD DAWN...POSSIBLY DENSE IN
LOCATIONS CLOSER TO THE VIRGINIA BORDER THAT SAW SOME DECENT RAINS ON
TUESDAY AFTERNOON.
THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT WITH THE MAIN FEATURES
AFFECTING THE SHORT TERM FORECAST. THEY AGREE THAT STRONG RIDGING
WILL REMAIN PARKED OFF TO THE SOUTHWEST OF THE AREA...IN NORTHERN
TEXAS...AND THAT THE EASTERN THIRD OF THE NATION WILL BE IN BROAD
TROUGHING...DOWNSTREAM OF THE RIDGE. LOCALLY...EAST KENTUCKY WILL BE
UNDER THE INFLUENCE OF NORTHWEST FLOW WITH A COUPLE OF WEAK
SHORTWAVES PASSING OVERHEAD INTO THURSDAY. ONE OF THESE WAVES IS
PASSING THIS MORNING AND IS PARTIALLY RESPONSIBLE FOR THE CURRENT
CONVECTION IMPACTING OUR WESTERNMOST COUNTIES. THE NEXT WILL COME
THROUGH THIS EVENING AND SHOULD BRING AN UPTICK IN CONVECTIVE
POTENTIAL TO THE AREA...THOUGH ITS BEST INFLUENCE WILL LIKELY BE FELT
FURTHER TO THE EAST. TOWARD THE END OF THE PERIOD...THE PATTERN
BECOMES MORE ZONAL AS THE EASTERN TROUGH STARTS TO FLATTEN OUT AND
THE WESTERN RIDGE SHIFTS SOUTH. GIVEN THE MODEL SIMILARITIES HAVE
FOLLOWED A BLENDED SOLUTION WITH A STRONG LEAN TOWARD THE HIGHER
RESOLUTION NAM12 OUTSIDE OF THE NEXT 12 HOURS...WHEN THE HRRR IS
PREFERRED.
SENSIBLE WEATHER WILL FEATURE THE CURRENT CONVECTION WINDING DOWN
LATER THIS MORNING IN THE SOUTH WITH BUILDING INSTABILITY POSSIBLY
HELPING TO KICK OFF SOME MORE IN THE FAR EAST LATER IN THE
AFTERNOON...SIMILAR TO WHAT OCCURRED ON TUESDAY. THIS SHOULD BE THE
LAST THREAT OF CONVECTION THROUGH THE SHORT TERM...THOUGH...AS
LIMITED UPPER LEVEL SUPPORT AND WEAK SFC HIGH PRESSURE WILL LIKELY
SUPPRESS CONVECTION AFTER 00Z TONIGHT. AS SUCH...WE CAN EXPECT
ANOTHER WARM AND HUMID COUPLE OF DAYS WITH HEAT INDICES MAXING OUT
BETWEEN 95 AND 100 DEGREES EACH AFTERNOON. WILL MENTION THIS IN THE
FORTHCOMING HWO. AT NIGHT...PATCHY VALLEY FOG WILL BE THE NORM WITH A
SMALL RIDGE TO VALLEY TEMPERATURE SPLIT EACH NIGHT AS TEMPERATURES
AND DEWPOINTS KEEP A MUGGINESS IN THE AIR...AND PATCHY FOG IN THE
VALLEYS TOWARD DAWN.
FOLLOWED A BLEND OF PERSISTENCE...EXISTING GRIDS...AND THE LATEST
MET GUIDANCE FOR TEMPERATURES THROUGH THE SHORT TERM. AS FOR POPS...
ENDED UP JUST ON THE HIGH SIDE OF GUIDANCE TODAY AND IN LINE WITH IT
FOR TONIGHT AND THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 355 AM EDT WED AUG 1 2012
OVERALL...THE LONG TERM LOOKS TO BE UNSETTLED WITH QUITE A BIT OF
RAIN POTENTIAL OVER THE PERIOD. A BERMUDA HIGH IS EXPECTED TO BE
STRENGTHENING OVER THE ERN U.S. WHILE AN AREA OF LOW PRESSURE GAINS
MOMENTUM OVER CANADIAN PRAIRIES BENEATH A RELATIVELY ZONAL FLOW
ALOFT OVER THE OHIO VALLEY TO START THE PERIOD. RETURN FLOW IS
EXPECTED TO BE UNDER WAY BY FRIDAY...USHERING AMPLE MOISTURE BACK
INTO THE REGION WITH PWATS PROGGED TO BE AROUND 2 INCHES FROM LATE
FRIDAY THROUGH SUNDAY AFTERNOON.
GUIDANCE CONTINUES TO POINT TOWARDS A COUPLE OF SHORT WAVES SKIRTING
THE AREA AROUND THE FRIDAY/SATURDAY TIME FRAME. THE LATEST GFS ALONG
WITH THE GEM ARE STILL ADVERTISING A RATHER POTENT WAVE REACHING THE
TN VALLEY ON FRIDAY IN CONJUNCTION WITH MODEST ISENTROPIC LIFT AT
H85 OVER ERN KY DURING THE AFTERNOON. STILL NOT CONFIDENT ENOUGH TO
GO HIGHER THAN CHANCE AT THIS POINT BUT ANOTHER ROUND OF OFFERINGS
WITH THE SAME SOLUTIONS SHOULD WARRANT A BUMP UP TO LIKELY POPS FOR
AT LEAST PART OF THE CWA ON FRIDAY. SATURDAY IS LOOKING SIMILAR TO
FRIDAY...THOUGH WITH LESS IN THE WAY OF SHORT WAVE TRIGGERS...BUT
ATTAINABLE FCST CONVECTIVE TEMPS IN THE LOWER 80S ALONG WITH ANY
REMNANT BOUNDARIES FROM FRIDAY MAY BE ENOUGH TO GET THINGS GOING
BEFORE OUTFLOW PROCESSES TAKE OVER.
FOCUS THEN SHIFTS TO AN ALBERTA CLIPPER SYSTEM MOVING THROUGH THE
UPPER MIDWEST AND INTO THE GREAT LAKES ON SUNDAY. THE MODELS
CONTINUE TO COME INTO BETTER ALIGNMENT WITH THE TIMING OF THE SYSTEM
OVERALL. FORCING ASSOCIATED WITH THE COLD FRONT LOOKS TO BEGIN
APPROACHING THE AREA ON SUNDAY WITH SHOWERS AND THUNDERSTORMS
OVERSPREADING THE AREA DURING THE AFTERNOON AND EVENING BEFORE UPPER
LEVEL SUPPORT ARRIVES SUNDAY NIGHT INTO MONDAY. MODELS STILL SUGGEST
THE FRONT STALLING OVER THE AREA ON MONDAY AND DESPITE WHAT SHOULD
BE DIMINISHING MOISTURE BY THAT POINT...WILL KEEP CHANCE POPS FOR
MONDAY TO ACCOUNT FOR MODELS TENDENCIES TO BE A LITTLE FAST IN
MOVING THINGS OUT TOO QUICKLY THIS FAR OUT.
GIVEN THE INCREASING AGREEMENT AMONG THE MODELS...STAYED FAIRLY
CLOSE TO THE CONSENSUS NUMBERS FOR TEMPS THROUGHOUT THE PERIOD. THIS
RESULTED IN HIGHS ON FRIDAY AND SATURDAY RUNNING ABOVE NORMAL
BEFORE SLIDING BACK TOWARDS CLIMO FROM SUNDAY ONWARD. AFTER A MODEST
RIDGE/VALLEY SPLIT THURSDAY NIGHT...LOWS LOOK TO REMAIN WITHIN REACH
OF NORMAL THROUGHOUT THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 750 AM EDT WED AUG 1 2012
STRAY CONVECTION CONTINUES TO SPARSELY AFFECT THE AREA EARLY THIS
MORNING. THIS SHOULD CLEAR UP BY 14Z. OTHERWISE...VFR CONDITIONS
WILL DOMINATE THROUGH THE PERIOD. EXPECT TO SEE SOME PATCHY DENSE
VALLEY FOG LATE TONIGHT AND INTO EARLY THURSDAY MORNING...BUT THE
MAIN TAF SITES SHOULD REMAIN CLEAR. OUTSIDE OF ANY STRAY
THUNDERSTORMS TODAY...THE WINDS WILL BE LIGHT AND VARIABLE THROUGH
THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...GREIF
LONG TERM....MB
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
750 AM EDT WED AUG 1 2012
.UPDATE...
ISSUED AT 750 AM EDT WED AUG 1 2012
UPDATED THE GRIDS...MINORLY...TO BETTER REFLECT POPS EARLY THIS
MORNING. ALSO TWEAKED SKY...T AND TD GRIDS FOR CURRENT OBS AND
TRENDS. UPDATES HAVE BEEN SENT TO NDFD AND THE WEB.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 335 AM EDT WED AUG 1 2012
06Z SFC ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE LAYING ACROSS THE
NORTHWEST PORTION OF EASTERN KENTUCKY...RELATED TO A MINOR COLD FRONT
THAT IS PASSING THROUGH THE AREA EARLY THIS MORNING. THIS HAS JUST
RECENTLY HELPED TO TRIGGER A FEW CELLS OF CONVECTION IN THE WESTERN
PARTS OF THE CUMBERLAND VALLEY...DRIFTING SOUTHEAST INTO THE
SOUTHERN INTERSTATE 75 CORRIDOR. ON SATELLITE...THE CLOUDS HAVE
INCREASED DURING THE PAST COUPLE OF HOURS IN RESPONSE TO THE
BOUNDARY AND SOME ENERGY PASSING THROUGH AT MID LEVELS. THE CLOUDS
WILL HELP TO LIMIT ANY FURTHER DROP IN TEMPERATURES THROUGH THE REST
OF THE NIGHT. AS IT STANDS...A MINOR RIDGE TO VALLEY TEMPERATURE
SPLIT ON THE ORDER OF ABOUT 5 DEGREES EXISTS OUT THERE...MAINLY IN
THE NORTHEAST AS OF 3 AM EDT. LOW DEWPOINT DEPRESSIONS ARE ALSO
FOUND IN THE VALLEYS AND ANY PLACE THAT MANAGE TO STAY MOSTLY CLEAR
CAN EXPECT PATCHY FOG IN THE VALLEYS TOWARD DAWN...POSSIBLY DENSE IN
LOCATIONS CLOSER TO THE VIRGINIA BORDER THAT SAW SOME DECENT RAINS ON
TUESDAY AFTERNOON.
THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT WITH THE MAIN FEATURES
AFFECTING THE SHORT TERM FORECAST. THEY AGREE THAT STRONG RIDGING
WILL REMAIN PARKED OFF TO THE SOUTHWEST OF THE AREA...IN NORTHERN
TEXAS...AND THAT THE EASTERN THIRD OF THE NATION WILL BE IN BROAD
TROUGHING...DOWNSTREAM OF THE RIDGE. LOCALLY...EAST KENTUCKY WILL BE
UNDER THE INFLUENCE OF NORTHWEST FLOW WITH A COUPLE OF WEAK
SHORTWAVES PASSING OVERHEAD INTO THURSDAY. ONE OF THESE WAVES IS
PASSING THIS MORNING AND IS PARTIALLY RESPONSIBLE FOR THE CURRENT
CONVECTION IMPACTING OUR WESTERNMOST COUNTIES. THE NEXT WILL COME
THROUGH THIS EVENING AND SHOULD BRING AN UPTICK IN CONVECTIVE
POTENTIAL TO THE AREA...THOUGH ITS BEST INFLUENCE WILL LIKELY BE FELT
FURTHER TO THE EAST. TOWARD THE END OF THE PERIOD...THE PATTERN
BECOMES MORE ZONAL AS THE EASTERN TROUGH STARTS TO FLATTEN OUT AND
THE WESTERN RIDGE SHIFTS SOUTH. GIVEN THE MODEL SIMILARITIES HAVE
FOLLOWED A BLENDED SOLUTION WITH A STRONG LEAN TOWARD THE HIGHER
RESOLUTION NAM12 OUTSIDE OF THE NEXT 12 HOURS...WHEN THE HRRR IS
PREFERRED.
SENSIBLE WEATHER WILL FEATURE THE CURRENT CONVECTION WINDING DOWN
LATER THIS MORNING IN THE SOUTH WITH BUILDING INSTABILITY POSSIBLY
HELPING TO KICK OFF SOME MORE IN THE FAR EAST LATER IN THE
AFTERNOON...SIMILAR TO WHAT OCCURRED ON TUESDAY. THIS SHOULD BE THE
LAST THREAT OF CONVECTION THROUGH THE SHORT TERM...THOUGH...AS
LIMITED UPPER LEVEL SUPPORT AND WEAK SFC HIGH PRESSURE WILL LIKELY
SUPPRESS CONVECTION AFTER 00Z TONIGHT. AS SUCH...WE CAN EXPECT
ANOTHER WARM AND HUMID COUPLE OF DAYS WITH HEAT INDICES MAXING OUT
BETWEEN 95 AND 100 DEGREES EACH AFTERNOON. WILL MENTION THIS IN THE
FORTHCOMING HWO. AT NIGHT...PATCHY VALLEY FOG WILL BE THE NORM WITH A
SMALL RIDGE TO VALLEY TEMPERATURE SPLIT EACH NIGHT AS TEMPERATURES
AND DEWPOINTS KEEP A MUGGINESS IN THE AIR...AND PATCHY FOG IN THE
VALLEYS TOWARD DAWN.
FOLLOWED A BLEND OF PERSISTENCE...EXISTING GRIDS...AND THE LATEST
MET GUIDANCE FOR TEMPERATURES THROUGH THE SHORT TERM. AS FOR POPS...
ENDED UP JUST ON THE HIGH SIDE OF GUIDANCE TODAY AND IN LINE WITH IT
FOR TONIGHT AND THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 355 AM EDT WED AUG 1 2012
OVERALL...THE LONG TERM LOOKS TO BE UNSETTLED WITH QUITE A BIT OF
RAIN POTENTIAL OVER THE PERIOD. A BERMUDA HIGH IS EXPECTED TO BE
STRENGTHENING OVER THE ERN U.S. WHILE AN AREA OF LOW PRESSURE GAINS
MOMENTUM OVER CANADIAN PRAIRIES BENEATH A RELATIVELY ZONAL FLOW
ALOFT OVER THE OHIO VALLEY TO START THE PERIOD. RETURN FLOW IS
EXPECTED TO BE UNDER WAY BY FRIDAY...USHERING AMPLE MOISTURE BACK
INTO THE REGION WITH PWATS PROGGED TO BE AROUND 2 INCHES FROM LATE
FRIDAY THROUGH SUNDAY AFTERNOON.
GUIDANCE CONTINUES TO POINT TOWARDS A COUPLE OF SHORT WAVES SKIRTING
THE AREA AROUND THE FRIDAY/SATURDAY TIME FRAME. THE LATEST GFS ALONG
WITH THE GEM ARE STILL ADVERTISING A RATHER POTENT WAVE REACHING THE
TN VALLEY ON FRIDAY IN CONJUNCTION WITH MODEST ISENTROPIC LIFT AT
H85 OVER ERN KY DURING THE AFTERNOON. STILL NOT CONFIDENT ENOUGH TO
GO HIGHER THAN CHANCE AT THIS POINT BUT ANOTHER ROUND OF OFFERINGS
WITH THE SAME SOLUTIONS SHOULD WARRANT A BUMP UP TO LIKELY POPS FOR
AT LEAST PART OF THE CWA ON FRIDAY. SATURDAY IS LOOKING SIMILAR TO
FRIDAY...THOUGH WITH LESS IN THE WAY OF SHORT WAVE TRIGGERS...BUT
ATTAINABLE FCST CONVECTIVE TEMPS IN THE LOWER 80S ALONG WITH ANY
REMNANT BOUNDARIES FROM FRIDAY MAY BE ENOUGH TO GET THINGS GOING
BEFORE OUTFLOW PROCESSES TAKE OVER.
FOCUS THEN SHIFTS TO AN ALBERTA CLIPPER SYSTEM MOVING THROUGH THE
UPPER MIDWEST AND INTO THE GREAT LAKES ON SUNDAY. THE MODELS
CONTINUE TO COME INTO BETTER ALIGNMENT WITH THE TIMING OF THE SYSTEM
OVERALL. FORCING ASSOCIATED WITH THE COLD FRONT LOOKS TO BEGIN
APPROACHING THE AREA ON SUNDAY WITH SHOWERS AND THUNDERSTORMS
OVERSPREADING THE AREA DURING THE AFTERNOON AND EVENING BEFORE UPPER
LEVEL SUPPORT ARRIVES SUNDAY NIGHT INTO MONDAY. MODELS STILL SUGGEST
THE FRONT STALLING OVER THE AREA ON MONDAY AND DESPITE WHAT SHOULD
BE DIMINISHING MOISTURE BY THAT POINT...WILL KEEP CHANCE POPS FOR
MONDAY TO ACCOUNT FOR MODELS TENDENCIES TO BE A LITTLE FAST IN
MOVING THINGS OUT TOO QUICKLY THIS FAR OUT.
GIVEN THE INCREASING AGREEMENT AMONG THE MODELS...STAYED FAIRLY
CLOSE TO THE CONSENSUS NUMBERS FOR TEMPS THROUGHOUT THE PERIOD. THIS
RESULTED IN HIGHS ON FRIDAY AND SATURDAY RUNNING ABOVE NORMAL
BEFORE SLIDING BACK TOWARDS CLIMO FROM SUNDAY ONWARD. AFTER A MODEST
RIDGE/VALLEY SPLIT THURSDAY NIGHT...LOWS LOOK TO REMAIN WITHIN REACH
OF NORMAL THROUGHOUT THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 750 AM EDT WED AUG 1 2012
STRAY CONVECTION CONTINUES TO SPARSELY AFFECT THE AREA EARLY THIS
MORNING. THIS SHOULD CLEAR UP BY 14Z. OTHERWISE...VFR CONDITIONS
WILL DOMINATE THROUGH THE PERIOD. EXPECT TO SEE SOME PATCHY DENSE
VALLEY FOG LATE TONIGHT AND INTO EARLY THURSDAY MORNING...BUT THE
MAIN TAF SITES SHOULD REMAIN CLEAR. OUTSIDE OF ANY STRAY
THUNDERSTORMS TODAY...THE WINDS WILL BE LIGHT AND VARIABLE THROUGH
THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM....MB
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS CARIBOU ME
834 AM EDT WED AUG 1 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS THE GULF OF MAINE EARLY TODAY. A
COLD FRONT APPROACHING FROM THE WEST AND NORTHWEST WEAKEN AS IT
CROSSES THE AREA TONIGHT. ANOTHER COLD FRONT WILL CROSS THE AREA
ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: UPDATED THE POPS AND SKY TO BRING PERCENTAGES UP AND
INCREASE THE AREAL EXTENT FURTHER NNE PER THE LATEST RADAR AND
VISIBLE SATL IMAGERY. HRRR AND RAP MODEL BOTH SHOW NORTHERN EXTENT
OF RAINFALL MAKING ITS WAY INTO PRESQUE ISLE AND HOULTON AFTER
12Z. THE NAM/GFS/CANADIAN REGIONAL ALL SHOW PRECIP TOO FAR SOUTH
AND EAST. THE 00Z ECMWF LINES A BIT BETTER W/THE HRRR AND RAP.
DECIDED TO LEAN TOWARD THE HRRR W/TH ECMWF BLENDED IN AND RE-
ADJUSTED THE POPS WHICH SHOW 60-80% POPS ACROSS THE HOULTON-
MILLINOCKET REGIONS AND 20-30% FOR THE CARIBOU-PRESQUE ISLE
AREAS. FURTHER NORTH AND WEST, A DRY DAY IN STORE. STRATUS WILL
HOLD ON LONGER AS WELL W/DEFINED CLEAR ZONE ACROSS THE WEST-NORTHWEST.
CLEARING WILL TAKE PLACE THIS AFTERNOON ACROSS THE EASTERN 1/2 OF THE
CWA W/RAIN ENDING.
PREVIOUS DISCUSSION...
WELL-DEFINED...COMPACT SFC LOW PRES CNTRD E OF BOS ATTM AND CONTS
TO LIFT RATHER QUICKLY NE. EXPECT RAIN CONT TO SPREAD NEWRD
AFFECTING MOST OF SRN AND SERN AREAS W/THE NRN EDGE OF THE SHIELD
REACHING E CENTRAL AREAS...PSBLY AS FAR N AS KHUL BY MID AM BEFORE
THE ENTIRE AREAS SHIFTS E OF THE FA BY LATE AM/ERLY AFTN. THIS
GENERAL AREA OF RAIN WILL LIKELY DROP .25-.50 INCHES ACROSS MOST
OF OUR SRN/SERN AREAS.
OTHRWS...A WEAKENING COLD FRONT APPROACHING FROM THE W AND NW WILL
LIKELY BE CLOSE ENUF TO TRIGGER SOME AFTN SHOWERS AND PSBL THUNDER
MAINLY ACROSS OUR WRN/NWRN AREAS W/ SOME ISOLATED ACTIVITY REACHING
CENTRAL AND PSBLY EVN ERN AREAS TNGT AS THIS FRONT DISSIPATES
ACROSS THE REGION.
CLOUDS...SOME PRECIP AND A BRIEF WEAK NRLY FLOW BEHIND THE
DEPARTING SFC LOW WILL LIKELY RESULT IN COOLER TEMPS ACROSS THE
REGION TDY W/ LOW TNGT PRETTY SIMILAR TO THE LAST FEW NGTS...
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
WARM...HUMID CONDITIONS ARE EXPECTED ON THURSDAY IN ADVANCE OF A
COLD FRONT APPROACHING FROM THE WEST. IMPULSES MOVING THROUGH THE
WEST TO SOUTHWEST FLOW ALOFT WILL BRING THE CHANCE FOR SHOWERS AND
THUNDERSTORMS ESPECIALLY DURING THE AFTERNOON HOURS. THURSDAY
NIGHT SHOULD BE MAINLY DRY ALTHOUGH COULDNT RULE OUT A FEW SHOWERS
ACROSS NORTHWEST MAINE AS THE COLD FRONT APPROACHES. THE COLD
FRONT WILL CROSS THE REGION ON FRIDAY WITH THE CHANCE FOR SHOWERS
AND THUNDERSTORMS ESPECIALLY ACROSS DOWNEAST AREAS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FRIDAY NIGHT AND
SATURDAY AS FRONTAL BOUNDARY REMAINS JUST TO OUR SOUTH. THE FRONT
WILL PUSH BACK TO OUR NORTH SATURDAY NIGHT AND EARLY SUNDAY WITH
WARM AND HUMID CONDITIONS EXPECTED. A COLD FRONT WILL CROSS THE
REGION ON MONDAY WITH THE CHANCE FOR SHOWERS. DRIER WEATHER SHOULD
RETURN FOR TUESDAY.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: IFR CONDS EXPECTED AT KBHB AND KBGR INTO THIS AM IN
RAIN AND STRATUS W/ CONDS IMPRVG TO VFR BY MID-LATE AM. IFR IN
AREAS OF FOG RETURNS AT OUR SRN TAF SITES LATER THIS EVE AND
OVERNIGHT. MAINLY VFR CONDS EXPECTED AT THE REMAINING TAF SITES THO
EXPECT SOME PSBL MVFR AT KHUL ERLY THIS AM AND PSBL MVFR/IFR IN
PATCHY FOG LATER TNGT...
SHORT TERM: MAINLY VFR EXCEPT THE CHANCE FOR MVFR/IFR IN ANY SCT
SHOWERS AND TSTMS AND PATCHY MORNING FOG.
&&
.MARINE...
NEAR TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY LEVELS THRU TONIGHT. VISIBILITIES WILL BE REDUCED IN
RAIN AND PATCHY FOG THIS MORNING AND IN AREAS OF FOG TNGT.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SCA LEVELS THROUGH THE
PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/KHW
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/KHW
MARINE...HEWITT/KHW/DUDA
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
956 AM EDT WED AUG 1 2012
.SYNOPSIS...
INCREASED HUMIDITY AND A WEAK UPPER LEVEL DISTURBANCE WILL SUPPORT
SHOWER AND THUNDERSTORM CHANCES TODAY. HIGH PRESSURE WILL BRING
DRY WEATHER THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECENT HRRR MODEL OUTPUT CONTINUES TO SHOW THAT SCATTERED THUNDERSTORMS
CAN DEVELOP THIS AFTERNOON INTO EARLY EVENING, AHEAD OF A SLOWLY
MOVING EASTBOUND WEAK UPPER LEVEL SHORT WAVE TROUGH.
NOCTURNAL COOLING AND THE TROUGHS EXIT EAST WILL STABILIZE
CONDITIONS TONIGHT.
FORECASTED TEMPERATURES TO AGAIN BE SLIGHTLY WARMER THAN NORMAL,
BASED ON RECENT GFS AND NAM MOS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BRING DRY WEATHER AND FOR THURSDAY AND FRIDAY.
FORECASTED TEMPERATURES TO CONTINUE WARMER THAN NORMAL, WITH AFTERNOON
HIGHS THURSDAY AND FRIDAY WELL INTO THE 80S. EARLY MORNING LOWS WILL
BE SLIGHTLY WARMER THAN NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONTINUED HUMID AND VERY WARM CONDITIONS WILL EVOLVE INTO UNSETTLED
CONDITIONS THIS PERIOD.
CONSENSUS OF MODELS SHOW A STRONG UPPER LEVEL TROUGH AND CLOSED
SURFACE LOW TRACKING, EAST ALONG THE CANADIAN BORDER THIS WEEKEND
THAT WILL PASS EASTWARD THROUGH THE EASTERN GREAT LAKES MONDAY.
INSTABILITY WILL BE INCREASED AS ALREADY HUMID CONDITIONS WILL BE
FURTHER AUGMENTED BY LOW LEVEL SOUTHERLY WINDS PROVIDING AN
ADDITIONAL INFLUX OF GULF MOISTURE. SO EXPECT A DECENT CHANCE OF
THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY THIS WEEKEND.
SURFACE HIGH PRESSURE IS PROGGED TO PROVIDE DRY, STABLE CONDITIONS
TUESDAY.
FORECAST TEMPERATURES TO CONTINUE AT LEAST SLIGHTLY WARMER THAN
NORMAL BASED ON BLEND OF RECENT GFS AND ECMWF MOS AND NAEFS MEDIAN
VALUES.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MAINLY VFR INTO TONIGHT, ALTHOUGH SCATTERED THUNDERSTORMS
MAY CAUSE BRIEF RESTRICTIONS. THESE WERE NOT INCLUDED IN TAF AS
NOT CONFIDENT TO PINPOINT FOR ANY LOCATION.
DID INCLUDE MVFR RESTRICTIONS FOR FOG DEVELOPMENT LATE TONIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
EXPECT VFR AND GENERALLY DRY CONDITIONS FOR THURSDAY AND FRIDAY.
RESTRICTIONS WILL BE POSSIBLE AGAIN WITH THUNDERSTORMS SATURDAY
AND SUNDAY...AS ANOTHER LOW PRESSURE SYSTEM MOVES INTO THE GREAT
LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
907 AM EDT WED AUG 1 2012
.SYNOPSIS...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL DRIFT THROUGH THE GREAT LAKES REGION TODAY...
BRINGING SEASONABLY WARM AND DRY CONDITIONS. MEANWHILE...THE NEXT
LOW PRESSURE SYSTEM AND COOL FRONT...WILL MIGRATE ALONG THE CANADIAN
BORDER. THIS LOW WILL MOVE THROUGH TONIGHT...WITH ITS TRAILING COOL
FRONT SLIDING THROUGH THURSDAY. SCATTERED SHOWERS AND STORMS...WILL
ACCOMPANY THIS FRONT. HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...BUT THE COOL FRONT WILL BECOME STATIONARY...JUST SOUTH OF
THE REGION...WITH NORTHERN PLAINS LOW PRESSURE APPROACHING FROM THE
WEST. THE NEXT CHANCE OF RAIN...WILL APPROACH WITH THIS SYSTEM OVER
THE WEEKEND.
&&
.UPDATE...
ISSUED AT 907 AM EDT WED AUG 1 2012
GOING TO BE A BEAUTIFUL DAY ALL THROUGHOUT NORTHERN MICHIGAN
TODAY...COURTESY OF LOW/MID LEVEL RIDGE AXIS DIRECTLY OVERHEAD.
STILL WATCHING THE EVOLUTION OF SOME PESKY STRATUS ACROSS
NORTHEAST LOWER INTO LAKE HURON WITHIN RESIDUAL LOW LEVEL MOISTURE
AXIS BENEATH A VERY SHARP NEAR-SURFACE INVERSION. PER TRENDS NOTED
YESTERDAY AND THE NATURE OF THESE THINGS...WILL LIKELY SEE THIS
CLOUD BAND HANG ON FOR A FEW MORE HOURS AND HAVE ADJUSTED THE
CLOUD FORECAST AS SUCH. HOWEVER...EARLY AUGUST SUN SHOULD WORK ITS
MAGIC BY LATE MORNING...HELPING RAPIDLY ERODE SAID CLOUD DECK BY
AROUND 16Z AT THE LATEST.
HAVE ALSO SEEN QUITE A BIT OF FOG OVERNIGHT AS EXPECTED...BUT THIS
TOO IS ON THE WAY OUT. QUITE DRY AIRMASS (12Z APX RAOB PWAT WAS
JUST 0.42 INCHES!) DUE OVERHEAD COMBINED WITH INCREASED MIXING
SHOULD SEND DEW POINTS PLUMMETING FOR INLAND LOCATIONS INTO THE
AFTERNOON...AND PER TRENDS UPSTREAM YESTERDAY AND STRONG
GUIDANCE/FORECAST RAOB HINTS...HAVE LOWERED READINGS DOWN INTO THE
40S. THIS WILL RESULT IN MINIMUM RH VALUES DOWN IN THE MID
20S...BUT WITH LIGHT WINDS AND RECENT WIDESPREAD RAIN...NO FIRE
CONCERNS EXPECTED. OUTSIDE OF THAT...GOING HIGHS WELL INTO THE 80S
LOOK JUST FINE. OVERALL A GREAT START TO THE MONTH...ENJOY!
UPDATE ISSUED AT 646 AM EDT WED AUG 1 2012
BAND OF STRATUS HAS DEVELOPED OVER THE LAST HOUR OR SO ACROSS NE
LOWER AND INTERIOR EASTERN UPPER...WHILE SHALLOW GROUND FOG
CONTINUED IN MANY LOW LYING AREAS. BOTH OF THESE WILL MIX
OUT/ERODE OVER THE NEXT COUPLE OF HOURS AS DAYTIME HEATING MIXES
IN SOME QUITE DRY AIR THROUGH 700MB. ALSO HAD TO COOL THE LOWEST
LYING AREAS WHICH DROPPED INTO THE MIDDLE/UPPER 40S. OTHERWISE THE
FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 348 AM EDT WED AUG 1 2012
TROUGHING OVER THE EASTERN COUNTRY AND AN UPPER RIDGE OVER THE
PLAINS...LEADS TO CONTINUED NW FLOW ALOFT INTO THE GREAT LAKES.
ONE SHORTWAVE IS WORKING ACROSS SRN ONTARIO AND IS ASSOCIATED
WITH AN AREA OF INCREASED UPPER LEVEL MOISTURE SEEN ON LATEST WV
IMAGERY. THIS FEATURE IS RUNNING INTO SOME MINOR UPPER RIDGING
OVER NRN MICHIGAN AND ASSOCIATED CLOUDS IN THE HIGHER LEVELS HAS
BEEN WANING WITH TIME. A STRONGER MORE DEFINED SHORTWAVE IS SEEN
IN MANITOBA ALSO PER SATELLITE DATA...AND IN RUC ANALYSIS FOCUSED
AROUND 700MB. THIS WAVE IS WORKING ON A WARM FRONT EXTENDING EAST
FROM A SFC LOW IN SRN MANITOBA. MAXIMUM LOW LEVEL CONVERGENCE
ASSOCIATED WITH A LLJ POINTING INTO THIS REGION AND WESTERN ONTARIO
HAS RESULTED IN AN MCS WITH A SWATH OF SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS. SKIES ARE CLEAR HERE...WITH ONLY SOME PATCHY HIGH
LEVEL CLOUDS SCRAPING EASTERN UPPER. ALTHOUGH SFC BASED MOISTURE
LINGERS IN THE NORTH WOODS (TDS IN THE 50S AND EVEN LOW 60S)...THE
LOW LEVEL MOISTURE PROFILE SHOWS DRYING FROM ALOFT. THIS HAS HELD
FOG DEVELOPMENT IN CHECK FROM AN AERIAL PERSPECTIVE.
TODAY...NO CONCERNS. HIGH PRESSURE AND LIGHT WINDS CURRENTLY OVER
THE FAR WESTERN GREAT LAKES WILL GRADUALLY WORK IN OVER THE SW
CWA/GTV BAY REGION THROUGH THE DAY. THIS WILL BRING A RETURN TO
SOUTHERLY WINDS THAT INCREASE MORE SO ACROSS EASTERN UPPER. A
LIGHTER WIND REGIME ACROSS NRN LOWER WILL LEAD TO THE DEVELOPMENT
OF LAKE BREEZES AND CONVERGENCE ACROSS NE LOWER. ONE WOULD TEND TO
BELIEVE THAT CUMULUS WILL BE MORE SO CONFINED TO THIS AREA.
HOWEVER...THE LOW LEVEL AIR MASS PROFILE (GENERALLY 700MB AND
BELOW)...IS QUITE DRY. CUMULUS WILL BE HARD TO COME BY WITH MAYBE
JUST SOME STRANDS OF CIRRUS OVERHEAD. A TRULY DECENT SUMMERTIME
DAY WITH TEMPERATURES IN THE WARMER SOUTHERLY FLOW RISING INTO THE
MID AND UPPER 80S ALL AREAS...OUTSIDE OF ONSHORE FLOW CREATED BY
MESOSCALE LAKE BREEZE/ONSHORE FLOW.
BY TONIGHT...THE LOW PRESSURE FROM MANITOBA WILL HAVE SHIFTED
ACROSS SRN MANITOBA...WITH A PRE-FRONTAL TROUGH/COLD FRONT AND
AXIS OF HIGHER THETA-E AIR TO LAY ACROSS EASTERN UPPER IN THE LATE
EVENING...AND ULTIMATELY IN NRN LOWER OVERNIGHT. THE UPPER WAVE
BECOMES SLIGHTLY MORE SHARP TONIGHT...AND THE THETA-E AIR
INCREASES IN THE EVENING BEFORE LOWERING OVERNIGHT...AS
CONVERGENCE ALONG THE TROUGH/COLD FRONT WANES IN THE DEPARTURE OF
THE SHORTWAVE ALOFT. FROM A PATTERN PERSPECTIVE...APPEARS AS
THOUGH THIS SCENARIO LEADS TO BEST CHANCES FOR SEEING
PRECIPITATION WILL BE ACROSS EASTERN UPPER AND FAR NRN LOWER
MICHIGAN WHEN FORCING IS MAXIMIZED WITH GREATEST MOISTURE/WARMTH
AND INSTABILITY (MUCAPES NEARING 1200 J/KG). POPS WILL DECREASE
NEARER THE SAGINAW BAY AS THE SHORTWAVE FORCING AND LOW LEVEL
CONVERGENCE MAXIMUMS DON`T QUITE REACH. REGARDLESS...THE BOUNDARY
DOES WORK THROUGH THIS AREA AS WELL. THE PRECIPITATION PICTURE
BEING PAINTED HERE IS FOR BEST/AND MOST PROLONGED CHANCE FOR
SEEING SHOWERS AND STORMS IN THE NRN HALF OF THE CWA. WILL KEEP
TREND OF ONLY 40% CHANCE THERE WITH 30% FURTHER SOUTH. JUST HAVE
TOO MANY CONCERNS REVOLVING AROUND ANTECEDENT RELATIVELY DRY AIR
MASS...ESPECIALLY THE LOW LEVELS WHICH DON`T EXACTLY DON`T BLOW MY
MIND IN A MOISTURE ADVECTION PERSPECTIVE. THIS FURTHER SUPPORTED
BY LACK OF/NO FGEN IN THE H8-H5 LAYER. ALL-IN-ALL...THIS IS
SEEMINGLY A LACKLUSTER EFFORT FOR PRECIPITATION. CAN FORESEE A HIT
AND MISS SHOWERY IDEA NORTH...WITH DECAYING/LESS AREAL COVERAGE
FURTHER SOUTH INTO THE PRE-DAWN HOURS HOURS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 348 AM EDT WED AUG 1 2012
NORTHERN HEMISPHERIC LARGE SCALE PATTERN CONFIGURATION ENSURES
CURRENT NOAM PATTERN IN NO HURRY TO CHANGE ANYTIME SOON...PLACING
THE NORTHERN LAKES IN PERSISTENT...AND AT TIMES ACTIVE...NORTHWEST
FLOW REGIME THROUGH THE REMAINDER OF THE WORK WEEK. CONSISTENT MID
RANGE GUIDANCE SUPPORT FOR SOME RELAXATION IN EASTERN NOAM TROUGHING
OVER THE WEEKEND...ALLOWING RATHER POTENT SHORTWAVE TO DIVE INTO THE
NORTHERN PLAINS...FORCING DOWNSTREAM HEIGHT RISES AND MORE
IMPRESSIVE SURGE OF LOW LEVEL MOISTURE INTO THE REGION. THIS SETS
THE STAGE FOR A POTENTIALLY ACTIVE (SEVERE WEATHER?) WEEKEND AS SAID
WAVES PLOWS THROUGH A SEASONABLY MOIST...INCREASINGLY UNSTABLE
AIRMASS. IN LIGHT OF THE ABOVE...FORECAST CONCERNS CENTER ON
MULTI-PERIOD PRECIP POTENTIAL...AS WELL AS TEMPERATURE AND CLOUD
TRENDS THROUGHOUT.
START OF THE PERIOD SHAPING UP TO BE SOMEWHAT ACTIVE AS LOW
AMPLITUDE WAVE AND ATTENDANT SURFACE LOW DRAG A SLOW MOVING COLD
FRONT SOUTH ACROSS THE MITT THURSDAY. ALTHOUGH BEST MID LEVEL
SUPPORT ACTUALLY PUSHES EAST EARLY...STILL NICE ENOUGH TRIFECTA OF
WEAKISH RER JET DYNAMICS...FRONTAL INDUCED CONVERGENCE...AND FOLDING
OVER THETA-E RIDGE TO SUPPORT INHERITED SHOWER AND THUNDERSTORM
THREAT. GREATEST POTENTIAL LIKELY SOUTH OF THE BIG BRIDGE...
ESPECIALLY IN THE ALL-TO-OFTEN FAVORED NORTHEAST LOWER WHERE LOW
LEVEL CONVERGENCE WILL BE MAXIMIZED. ML CAPE VALUES HOVERING AROUND
1K J/KG AND CORE OF BULK SHEAR REMAINING POST-FRONTAL AND TO OUR
NORTH SUGGEST STORMS SHOULD BEHAVE THEMSELVES. UNCERTAINTY INCREASES
TO ROUND OUT THE WORK WEEK. WHILE GUIDANCE TRENDS AGREE SURFACE
FRONT WILL PUSH SOUTH OF THE REGION (CONVECTIVE OUTFLOW ENHANCED?)
AS HIGH PRESSURE ROTATES SOUTHEAST ACROSS ONTARIO....SAME CANNOT BE
SAID FOR OFF THE DECK CONVERGENCE AXES AND CORE OF DEEPER MOISTURE.
SOME EVIDENCE THESE WILL RESIDE CLOSE ENOUGH TO KEEP AT LEAST A LOW
END SHOWER/STORM THREAT THURSDAY NIGHT INTO FRIDAY. WILL NOT GO THIS
ROUTE JUST YET (PROBS JUST TOO LOW)...BUT SOMETHING TO KEEP IN MIND
AS WE HEAD TOWARDS THE WEEKEND.
AS FOR THE WEEKEND...POTENTIALLY THE MOST "INTERESTING" PORTION OF
THE FORECAST AS GUIDANCE REMAINS AMAZINGLY STEADFAST PINWHEELING A
STRONG SHORTWAVE TROUGH THROUGH THE NORTHERN LAKES LATER SATURDAY
INTO SUNDAY. RETURN FLOW LOOKS TO BE WELL ESTABLISHED AHEAD OF THIS
FEATURE...WITH PERUSAL OF AVAILABLE MOISTURE PROGS SUGGESTING PWAT
VALUES AOA 1.50 INCHES. DYNAMICS LOOK PRETTY FORMIDABLE...WITH NEAR
NEUTRAL TILT WAVE AND POSSIBLE RER JET DYNAMICS OVERTOPPING A
SEASONABLY STRONG COLD FRONT. STILL SOME MINOR TIMING DIFFERENCES
WITH ALL THE ABOVE...BUT OVERALL A PRETTY WELL AGREED UPON FORECAST.
NO DOUBT A MODEL CONSENSUS WILL SUFFICE...FEATURING POSSIBLE SHOWERS
AND STORMS THROUGH THE WEEKEND...WITH THE GREATEST POTENTIAL
OVERNIGHT SATURDAY INTO EARLY SUNDAY. MUCH TOO EARLY TO GET CAUGHT
UP IN INSTABILITY PROGS AND SPECIFIC MID LEVEL WIND CORES...BUT FROM
A PATTERN RECOGNITION STANDPOINT...THIS SYSTEM LOOKS TO HAVE THE
POTENTIAL TO DRIVE A RATHER VIGOROUS (SEVERE?) SQUALL LINE THROUGH
AT LEAST A PORTION OF THE LAKES REGION. FRONTAL TIMING (CURRENT
TRENDS SUPPORT AN UNFAVORABLE EARLY SUNDAY MORNING FRONTAL PASSAGE)
MIGHT NOT EVEN MATTER MUCH GIVEN SUGGESTED DYNAMICS. DEFINITELY
SOMETHING TO MONITOR IN THE COMING DAYS. DRY WEATHER RETURNS FOR THE
BEGINNING OF NEXT WORK WEEK WITH AN AGGRESSIVE PUSH OF HIGH PRESSURE
BUILDING IN BEHIND THE DEPARTING FRONT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 907 AM EDT WED AUG 1 2012
MAINLY VFR CONDITIONS ARE EXPECTED THRU WEDNESDAY EVENING AS HIGH
PRESSURE PUSHES THROUGH NORTHERN MICHIGAN. THE EXCEPTION WILL BE A
BRIEF ROUND OF LOW STRATUS IMPACTING THE APN TERMINAL THROUGH MID
MORNING...WITH FOG BURNING OFF QUICKLY BY 14Z. OTHERWISE...LAKE
BREEZES WILL DEVELOP BY THIS AFTERNOON AND SKIES WILL BECOME
RATHER SUNNY WITH DAYTIME HEATING MIXING IN DRY AIR ALOFT. OUR
NEXT CHANCE OF SHRA/TSRA WILL DEVELOP LATE TONIGHT AS A WEAK FRONT
DROPS INTO NRN MICHIGAN. STILL APPEARS BETTER CHANCES OF PRECIP
WILL HOLD OFF UNTIL AFTER 06Z THURSDAY...BUT COVERAGE IS EXPECTED
TO BE SMALL. WILL INTRODUCE A VCSH IN THIS TAF ISSUANCE.
&&
.MARINE...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL SLIP SOUTH AND EAST OF THE REGION
TODAY...ALLOWING A SOUTHERLY AND INCREASING WIND FLOW TO
REINTRODUCE A HIGHER MOISTURE CONTENT TO THE GREAT LAKES. A COLD
FRONT ARRIVING LATE TONIGHT WILL WORK ON THIS AIR MASS AND BRING A
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO THE AREA. THE
PRESSURE GRADIENT TIGHTENS UP ENOUGH IN A NEUTRAL STABILITY
SCENARIO FOR A CHANCE AT LOW END SMALL CRAFT ADVISORIES LATER
TONIGHT. WILL NOT INTRODUCE THIS JUST YET...BUT COASTAL CONVERGENT
REGIONS OF NW LOWER MICHIGAN WILL BE THE BEST SHOT AT +25KT GUSTS.
THIS FRONT CONTINUES TO DIVE SOUTH OF US INTO THURSDAY...BEFORE
LIFTING BACK AS A WARM FRONT LATE FRIDAY NIGHT AND INTO THE
WEEKEND. NO OTHER WIND ISSUES ARE FORESEEN THROUGH THE WORK
WEEK...BUT ADVISORIES MAY BE NEEDED FOR THE WEEKEND AHEAD OF NEXT
MORE POTENT COLD FRONT...BOTH AHEAD OF AND BEHIND THIS BOUNDARY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MB
SHORT TERM...SD
LONG TERM...MB
AVIATION...SMD/LAWRENCE
MARINE...SD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
655 AM EDT WED AUG 1 2012
.SYNOPSIS...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL DRIFT THROUGH THE GREAT LAKES REGION TODAY...
BRINGING SEASONABLY WARM AND DRY CONDITIONS. MEANWHILE...THE NEXT
LOW PRESSURE SYSTEM AND COOL FRONT...WILL MIGRATE ALONG THE CANADIAN
BORDER. THIS LOW WILL MOVE THROUGH TONIGHT...WITH ITS TRAILING COOL
FRONT SLIDING THROUGH THURSDAY. SCATTERED SHOWERS AND STORMS...WILL
ACCOMPANY THIS FRONT. HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...BUT THE COOL FRONT WILL BECOME STATIONARY...JUST SOUTH OF
THE REGION...WITH NORTHERN PLAINS LOW PRESSURE APPROACHING FROM THE
WEST. THE NEXT CHANCE OF RAIN...WILL APPROACH WITH THIS SYSTEM OVER
THE WEEKEND.
&&
.UPDATE...
ISSUED AT 646 AM EDT WED AUG 1 2012
BAND OF STRATUS HAS DEVELOPED OVER THE LAST HOUR OR SO ACROSS NE
LOWER AND INTERIOR EASTERN UPPER...WHILE SHALLOW GROUND FOG
CONTINUED IN MANY LOW LYING AREAS. BOTH OF THESE WILL MIX
OUT/ERODE OVER THE NEXT COUPLE OF HOURS AS DAYTIME HEATING MIXES
IN SOME QUITE DRY AIR THROUGH 700MB. ALSO HAD TO COOL THE LOWEST
LYING AREAS WHICH DROPPED INTO THE MIDDLE/UPPER 40S. OTHERWISE THE
FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 348 AM EDT WED AUG 1 2012
TROUGHING OVER THE EASTERN COUNTRY AND AN UPPER RIDGE OVER THE
PLAINS...LEADS TO CONTINUED NW FLOW ALOFT INTO THE GREAT LAKES.
ONE SHORTWAVE IS WORKING ACROSS SRN ONTARIO AND IS ASSOCIATED
WITH AN AREA OF INCREASED UPPER LEVEL MOISTURE SEEN ON LATEST WV
IMAGERY. THIS FEATURE IS RUNNING INTO SOME MINOR UPPER RIDGING
OVER NRN MICHIGAN AND ASSOCIATED CLOUDS IN THE HIGHER LEVELS HAS
BEEN WANING WITH TIME. A STRONGER MORE DEFINED SHORTWAVE IS SEEN
IN MANITOBA ALSO PER SATELLITE DATA...AND IN RUC ANALYSES FOCUSED
AROUND 700MB. THIS WAVE IS WORKING ON A WARM FRONT EXTENDING EAST
FROM A SFC LOW IN SRN MANITOBA. MAXIMUM LOW LEVEL CONVERGENCE
ASSOCIATED WITH A LLJ POINTING INTO THIS REGION AND WESTERN ONTARIO
HAS RESULTED IN AN MCS WITH A SWATH OF SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS. SKIES ARE CLEAR HERE...WITH ONLY SOME PATCHY HIGH
LEVEL CLOUDS SCRAPING EASTERN UPPER. ALTHOUGH SFC BASED MOISTURE
LINGERS IN THE NORTH WOODS (TDS IN THE 50S AND EVEN LOW 60S)...THE
LOW LEVEL MOISTURE PROFILE SHOWS DRYING FROM ALOFT. THIS HAS HELD
FOG DEVELOPMENT IN CHECK FROM AN AERIAL PERSPECTIVE.
TODAY...NO CONCERNS. HIGH PRESSURE AND LIGHT WINDS CURRENTLY OVER
THE FAR WESTERN GREAT LAKES WILL GRADUALLY WORK IN OVER THE SW
CWA/GTV BAY REGION THROUGH THE DAY. THIS WILL BRING A RETURN TO
SOUTHERLY WINDS THAT INCREASE MORE SO ACROSS EASTERN UPPER. A
LIGHTER WIND REGIME ACROSS NRN LOWER WILL LEAD TO THE DEVELOPMENT
OF LAKE BREEZES AND CONVERGENCE ACROSS NE LOWER. ONE WOULD TEND TO
BELIEVE THAT CUMULUS WILL BE MORE SO CONFINED TO THIS AREA.
HOWEVER...THE LOW LEVEL AIR MASS PROFILE (GENERALLY 700MB AND
BELOW)...IS QUITE DRY. CUMULUS WILL BE HARD TO COME BY WITH MAYBE
JUST SOME STRANDS OF CIRRUS OVERHEAD. A TRULY DECENT SUMMERTIME
DAY WITH TEMPERATURES IN THE WARMER SOUTHERLY FLOW RISING INTO THE
MID AND UPPER 80S ALL AREAS...OUTSIDE OF ONSHORE FLOW CREATED BY
MESOSCALE LAKE BREEZE/ONSHORE FLOW.
BY TONIGHT...THE LOW PRESSURE FROM MANITOBA WILL HAVE SHIFTED
ACROSS SRN MANITOBA...WITH A PRE-FRONTAL TROUGH/COLD FRONT AND
AXIS OF HIGHER THETA-E AIR TO LAY ACROSS EASTERN UPPER IN THE LATE
EVENING...AND ULTIMATELY IN NRN LOWER OVERNIGHT. THE UPPER WAVE
BECOMES SLIGHTLY MORE SHARP TONIGHT...AND THE THETA-E AIR
INCREASES IN THE EVENING BEFORE LOWERING OVERNIGHT...AS
CONVERGENCE ALONG THE TROUGH/COLD FRONT WANES IN THE DEPARTURE OF
THE SHORTWAVE ALOFT. FROM A PATTERN PERSPECTIVE...APPEARS AS
THOUGH THIS SCENARIO LEADS TO BEST CHANCES FOR SEEING
PRECIPITATION WILL BE ACROSS EASTERN UPPER AND FAR NRN LOWER
MICHIGAN WHEN FORCING IS MAXIMIZED WITH GREATEST MOISTURE/WARMTH
AND INSTABILITY (MUCAPES NEARING 1200 J/KG). POPS WILL DECREASE
NEARER THE SAGINAW BAY AS THE SHORTWAVE FORCING AND LOW LEVEL
CONVERGENCE MAXIMUMS DON`T QUITE REACH. REGARDLESS...THE BOUNDARY
DOES WORK THROUGH THIS AREA AS WELL. THE PRECIPITATION PICTURE
BEING PAINTED HERE IS FOR BEST/AND MOST PROLONGED CHANCE FOR
SEEING SHOWERS AND STORMS IN THE NRN HALF OF THE CWA. WILL KEEP
TREND OF ONLY 40% CHANCE THERE WITH 30% FURTHER SOUTH. JUST HAVE
TOO MANY CONCERNS REVOLVING AROUND ANTECEDENT RELATIVELY DRY AIR
MASS...ESPECIALLY THE LOW LEVELS WHICH DON`T EXACTLY DON`T BLOW MY
MIND IN A MOISTURE ADVECTION PERSPECTIVE. THIS FURTHER SUPPORTED
BY LACK OF/NO FGEN IN THE H8-H5 LAYER. ALL-IN-ALL...THIS IS
SEEMINGLY A LACKLUSTER EFFORT FOR PRECIPITATION. CAN FORESEE A HIT
AND MISS SHOWERY IDEA NORTH...WITH DECAYING/LESS AREAL COVERAGE
FURTHER SOUTH INTO THE PRE-DAWN HOURS HOURS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 348 AM EDT WED AUG 1 2012
NORTHERN HEMISPHERIC LARGE SCALE PATTERN CONFIGURATION ENSURES
CURRENT NOAM PATTERN IN NO HURRY TO CHANGE ANYTIME SOON...PLACING
THE NORTHERN LAKES IN PERSISTENT...AND AT TIMES ACTIVE...NORTHWEST
FLOW REGIME THROUGH THE REMAINDER OF THE WORK WEEK. CONSISTENT MID
RANGE GUIDANCE SUPPORT FOR SOME RELAXATION IN EASTERN NOAM TROUGHING
OVER THE WEEKEND...ALLOWING RATHER POTENT SHORTWAVE TO DIVE INTO THE
NORTHERN PLAINS...FORCING DOWNSTREAM HEIGHT RISES AND MORE
IMPRESSIVE SURGE OF LOW LEVEL MOISTURE INTO THE REGION. THIS SETS
THE STAGE FOR A POTENTIALLY ACTIVE (SEVERE WEATHER?) WEEKEND AS SAID
WAVES PLOWS THROUGH A SEASONABLY MOIST...INCREASINGLY UNSTABLE
AIRMASS. IN LIGHT OF THE ABOVE...FORECAST CONCERNS CENTER ON
MULTI-PERIOD PRECIP POTENTIAL...AS WELL AS TEMPERATURE AND CLOUD
TRENDS THROUGHOUT.
START OF THE PERIOD SHAPING UP TO BE SOMEWHAT ACTIVE AS LOW
AMPLITUDE WAVE AND ATTENDANT SURFACE LOW DRAG A SLOW MOVING COLD
FRONT SOUTH ACROSS THE MITT THURSDAY. ALTHOUGH BEST MID LEVEL
SUPPORT ACTUALLY PUSHES EAST EARLY...STILL NICE ENOUGH TRIFECTA OF
WEAKISH RER JET DYNAMICS...FRONTAL INDUCED CONVERGENCE...AND FOLDING
OVER THETA-E RIDGE TO SUPPORT INHERITED SHOWER AND THUNDERSTORM
THREAT. GREATEST POTENTIAL LIKELY SOUTH OF THE BIG BRIDGE...
ESPECIALLY IN THE ALL-TO-OFTEN FAVORED NORTHEAST LOWER WHERE LOW
LEVEL CONVERGENCE WILL BE MAXIMIZED. ML CAPE VALUES HOVERING AROUND
1K J/KG AND CORE OF BULK SHEAR REMAINING POST-FRONTAL AND TO OUR
NORTH SUGGEST STORMS SHOULD BEHAVE THEMSELVES. UNCERTAINTY INCREASES
TO ROUND OUT THE WORK WEEK. WHILE GUIDANCE TRENDS AGREE SURFACE
FRONT WILL PUSH SOUTH OF THE REGION (CONVECTIVE OUTFLOW ENHANCED?)
AS HIGH PRESSURE ROTATES SOUTHEAST ACROSS ONTARIO....SAME CANNOT BE
SAID FOR OFF THE DECK CONVERGENCE AXES AND CORE OF DEEPER MOISTURE.
SOME EVIDENCE THESE WILL RESIDE CLOSE ENOUGH TO KEEP AT LEAST A LOW
END SHOWER/STORM THREAT THURSDAY NIGHT INTO FRIDAY. WILL NOT GO THIS
ROUTE JUST YET (PROBS JUST TOO LOW)...BUT SOMETHING TO KEEP IN MIND
AS WE HEAD TOWARDS THE WEEKEND.
AS FOR THE WEEKEND...POTENTIALLY THE MOST "INTERESTING" PORTION OF
THE FORECAST AS GUIDANCE REMAINS AMAZINGLY STEADFAST PINWHEELING A
STRONG SHORTWAVE TROUGH THROUGH THE NORTHERN LAKES LATER SATURDAY
INTO SUNDAY. RETURN FLOW LOOKS TO BE WELL ESTABLISHED AHEAD OF THIS
FEATURE...WITH PERUSAL OF AVAILABLE MOISTURE PROGS SUGGESTING PWAT
VALUES AOA 1.50 INCHES. DYNAMICS LOOK PRETTY FORMIDABLE...WITH NEAR
NEUTRAL TILT WAVE AND POSSIBLE RER JET DYNAMICS OVERTOPPING A
SEASONABLY STRONG COLD FRONT. STILL SOME MINOR TIMING DIFFERENCES
WITH ALL THE ABOVE...BUT OVERALL A PRETTY WELL AGREED UPON FORECAST.
NO DOUBT A MODEL CONSENSUS WILL SUFFICE...FEATURING POSSIBLE SHOWERS
AND STORMS THROUGH THE WEEKEND...WITH THE GREATEST POTENTIAL
OVERNIGHT SATURDAY INTO EARLY SUNDAY. MUCH TOO EARLY TO GET CAUGHT
UP IN INSTABILITY PROGS AND SPECIFIC MID LEVEL WIND CORES...BUT FROM
A PATTERN RECOGNITION STANDPOINT...THIS SYSTEM LOOKS TO HAVE THE
POTENTIAL TO DRIVE A RATHER VIGOROUS (SEVERE?) SQUALL LINE THROUGH
AT LEAST A PORTION OF THE LAKES REGION. FRONTAL TIMING (CURRENT
TRENDS SUPPORT AN UNFAVORABLE EARLY SUNDAY MORNING FRONTAL PASSAGE)
MIGHT NOT EVEN MATTER MUCH GIVEN SUGGESTED DYNAMICS. DEFINITELY
SOMETHING TO MONITOR IN THE COMING DAYS. DRY WEATHER RETURNS FOR THE
BEGINNING OF NEXT WORK WEEK WITH AN AGGRESSIVE PUSH OF HIGH PRESSURE
BUILDING IN BEHIND THE DEPARTING FRONT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 646 AM EDT WED AUG 1 2012
MAINLY VFR CONDITIONS ARE EXPECTED THRU WEDNESDAY EVENING AS HIGH
PRESSURE PUSHES THROUGH NORTHERN MICHIGAN. FOG WILL CONTINUOUSLY
IMPACT MBL AND PLN FOR ANOTHER HOUR OR SO. OTHERWISE...LAKE
BREEZES WILL DEVELOP BY THIS AFTERNOON AND SKIES WILL BECOME
RATHER SUNNY WITH DAYTIME HEATING MIXING IN DRY AIR ALOFT. OUR
NEXT CHANCE OF SHRA/TSRA WILL DEVELOP LATE TONIGHT AS A
WEAK FRONT DROPS INTO NRN MICHIGAN. STILL APPEARS BETTER CHANCES
OF PRECIP WILL HOLD OFF UNTIL AFTER 06Z THURSDAY...BUT COVERAGE IS
EXPECTED TO BE SMALL. WILL INTRO A VCSH IN THIS TAF ISSUANCE.
&&
.MARINE...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL SLIP SOUTH AND EAST OF THE REGION
TODAY...ALLOWING A SOUTHERLY AND INCREASING WIND FLOW TO
REINTRODUCE A HIGHER MOISTURE CONTENT TO THE GREAT LAKES. A COLD
FRONT ARRIVING LATE TONIGHT WILL WORK ON THIS AIR MASS AND BRING A
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO THE AREA. THE
PRESSURE GRADIENT TIGHTENS UP ENOUGH IN A NEUTRAL STABILITY
SCENARIO FOR A CHANCE AT LOW END SMALL CRAFT ADVISORIES LATER
TONIGHT. WILL NOT INTRODUCE THIS JUST YET...BUT COASTAL CONVERGENT
REGIONS OF NW LOWER MICHIGAN WILL BE THE BEST SHOT AT +25KT GUSTS.
THIS FRONT CONTINUES TO DIVE SOUTH OF US INTO THURSDAY...BEFORE
LIFTING BACK AS A WARM FRONT LATE FRIDAY NIGHT AND INTO THE
WEEKEND. NO OTHER WIND ISSUES ARE FORESEEN THROUGH THE WORK
WEEK...BUT ADVISORIES MAY BE NEEDED FOR THE WEEKEND AHEAD OF NEXT
MORE POTENT COLD FRONT...BOTH AHEAD OF AND BEHIND THIS BOUNDARY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...MB
SHORT TERM...SD
LONG TERM...MB
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS DULUTH MN
646 AM CDT WED AUG 1 2012
.AVIATION...12Z TAFS.
UNSTABLE ATMOSPHERE IN PLACE IS ALLOWING CU/TCU TO FORM AHEAD OF
FRONT IN NW MN. ALREADY A STORM HAS FIRED NEAR DTL AND HAVE A
VCTS AT BRD AS THIS CELL IS MOVING E. WAA WILL MAKE ADDITIONAL
DEVELOPMENT DIFFICULT TO TIME. HAVE ADDED VCSH AFTER 01Z TO
HYR/DLH/HIB/INL AHEAD OF SECOND FRONT EXPECTED NEAR THE CANADIAN
BORDER. VFR IS EXPECTED THROUGHOUT...EVEN IN THE VCNTY OF STORMS.
&&
.PREV DISCUSSION... /ISSUED 337 AM CDT WED AUG 1 2012/
SHORT TERM...
TODAY THROUGH THURSDAY AFTERNOON...
MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS TODAY...WITH A SLIGHT RISK OF STRONG
TO SEVERE STORMS SOUTH OF A LINE FROM HINCKLEY TO ASHLAND...ALONG
WITH VERY WARM AND HUMID CONDITIONS TODAY...AND A FEW SHOWERS AND
STORMS POSSIBLE ACROSS THE ARROWHEAD TOMORROW.
SURFACE HIGH PRESSURE AND DRY CONDITIONS ARE DOMINATING MUCH OF
THE WRN GREAT LAKES REGION THIS MORNING...WITH THE HIGH CENTERED
OVER CENTRAL WI. A LARGE UPPER LOW IS SITUATED OVER HUDSON BAY AND
AN UPPER HIGH IS POSITIONED OVER THE SRN PLAINS. A COUPLE WEAK
SHORT WAVES ARE RIDING IN BETWEEN THESE TWO FEATURES ACROSS THE
NRN PLAINS AND UPPER MIDWEST. A SFC LOW IS LOCATED OVER SRN
MANITOBA WITH A STATIONARY/WARM FRONT EXTENDING EWD INTO NRN
ONTARIO AND A TROUGH/COLD FRONT DROPPING SOUTH INTO THE DAKOTAS.
THIS LOW PRESSURE SYSTEM WILL CONTINUE TO TRACK EWD INTO THE
NORTHLAND TODAY AND EVENTUALLY TRIGGER SHOWERS AND STORMS ALONG
AND AHEAD OF THE FRONT.
THERE ARE SIGNIFICANT MODEL DIFFERENCES REGARDING THE CONVECTIVE
INITIATION THIS AFTERNOON...WITH THE 00Z GFS NAM AND ECMWF BEING
FAIRLY MORE AGGRESSIVE THAN THE 00Z GEM AND LATEST 06Z NAM. THE
MORE AGGRESSIVE MODELS ARE NOT INITIALIZING VERY WELL LOOKING AT
CURRENT REGIONAL RADAR...SO CONFIDENCE IN CHC POPS/SCT SHOWERS AND
STORMS IS MUCH WEAKER. UPPER LEVEL SUPPORT IS NOT REALLY EVIDENT
WITH A WEAK JET AND MINIMAL 500MB PVA. THE LOW LEVELS WILL BECOME
QUITE UNSTABLE WITH ML CAPE VALUES OVER 2000 J/KG AND 0-6KM SHEAR
AROUND 30 KT...ALONG WITH STEEP LAPSE RATES...WHICH WILL PROVIDE
THE NECESSARY INGREDIENTS FOR STRONG CONVECTION. SO...WILL LIKELY
SEE SHOWERS AND WEAK STORMS INITIATE ACROSS NE MN INTO CENTRAL MN
AND MOVE E/SEWD WITH THE FRONT AND POSSIBLY INTERACT WITH AN
INCREASINGLY UNSTABLE ATMOSPHERE TO PRODUCE A FEW STRONG TO
POSSIBLY SEVERE STORMS OVER THE SERN SECTIONS OF THE CWA...MAINLY
IN NW WI. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS.
CHECK THE LATEST DAY 1 CONVECTIVE OUTLOOK FROM SPC FOR FURTHER
INFORMATION.
THE OTHER CONCERN TODAY WILL BE THE HOT AND HUMID CONDITIONS ONCE
AGAIN. WE JUST ENDED THE SECOND WARMEST JULY ON RECORD IN DULUTH
YESTERDAY...AND NOW WE ARE STARTING OFF AUGUST ON A WARM NOTE AS
WELL. HIGHS WILL CLIMB INTO THE MID TO UPPER 80S WITH DEW POINTS
INTO THE MID TO UPPER 60S. THIS WILL CAUSE HEAT INDICES TO ROCKET
INTO THE LOWER TO MID 90S. TAKE THE NECESSARY PRECAUTIONS IF
OUTSIDE TODAY.
WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING SYSTEM
TONIGHT AND ALLOW CONDITIONS TO DRY OUT RAPIDLY. ANOTHER WEAK
UPPER WAVE SLIDES IN FROM THE NW TOMORROW AFTERNOON AND INTERACTS
WITH A WEAKLY UNSTABLE ATMOSPHERE TO TRIGGER OFF A FEW ISOLATED
STORMS ACROSS THE ARROWHEAD. AT THIS TIME CONFIDENCE IS LOW IN
PRECIP ON THURSDAY AFTERNOON. TEMPERATURES WILL BE SLIGHTLY COOLER
ON THURSDAY WITH LOWER...MORE COMFORTABLE HUMIDITIES. HIGHS WILL
ONLY REACH INTO THE LOWER TO MID 80S.
LONG TERM...
THURSDAY NIGHT THROUGH WEDNESDAY...
SFC RIDGING OVER THE EASTERN GREAT LAKES WILL KEEP THE FA DRY
THURSDAY NIGHT. ON FRIDAY...A LARGE CUT OFF UPPER LOW MOVES OUT OF
THE CANADIAN ROCKIES INTO THE CANADIAN PLAINS. THIS WILL PUSH A SFC
LOW CENTER OVER THE NORTHERN RED RIVER VALLEY IN CANADA WHILE A SFC
FRONT MOVES INTO THE RED RIVER VALLEY. PLENTY OF LOW LEVEL MOISTURE
WILL BE TRANSPORTED INTO THE FA AHEAD OF THE FRONT. SHOWERS AND
STORMS WILL FORM AHEAD OF THE FRONT AND OVERSPREAD THE FA THROUGH
FRIDAY NIGHT. THE COLD FRONT DEPARTS THE FA ON SATURDAY AS THE SFC
LOW OPENS UP AND THE UPPER LOW CONTINUES TO DRIVE EASTWARD THROUGH
SOUTH CENTRAL CANADA. A SECONDARY COLD FRONT WITH COLDER AIR ALOFT
FOLLOWS BEHIND AND CROSS THE FA SATURDAY NIGHT. SOME ISOLD
THUNDERSTORMS WILL ACCOMPANY THIS FRONT. A DRY PERIOD FOLLOWS FOR
SUNDAY THROUGH WEDNESDAY AS UPPER LEVEL/SFC RIDGING COVER THE
WESTERN GREAT LAKES.
AVIATION.../06Z TAF ISSUANCE/
PULLED OUT THE LLWS OVERNIGHT AS LATEST NAM BUFR SOUNDINGS SHOW
WIND SPEEDS UNDER 30 KNOTS BELOW 2000 FT AGL. ALSO SHIFTED THE
TIMING OF VCTS TO THE MORNING HOURS AS LATEST HRRR REFLECTIVITY
BRINGS IN SOME THUNDER AFTER 10Z ACROSS THE WESTERN AERODROMES.
A COLD FRONT WILL PASS THROUGH THE TERMINALS BY 18Z THAT WILL
BRING IN WESTERLY WINDS WITH A FEW GUSTS NEARING 20 KNOTS. WINDS
WILL DIMINISH BEFORE SUNSET AND COME FROM THE NORTHWEST.
&&
.POINT TEMPS/POPS...
DLH 87 64 80 57 / 40 30 10 0
INL 86 57 79 56 / 30 10 20 0
BRD 89 64 84 60 / 40 20 10 0
HYR 89 62 84 58 / 30 40 10 0
ASX 89 64 82 59 / 40 40 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS JACKSON MS
1015 AM CDT WED AUG 1 2012
.UPDATE...CLEAR SKIES ACROSS THE ARKLAMISS THIS MORNING FOR THE MOST
PART AS WEAK HIGH PRESSURE PREVAILS. THE GFS/NAM INDICATE A PRETTY
STRONG WAVE MOVING SOUTHEAST ACROSS THE ARKLAMISS THIS MORNING AND
THIS COMBINED WITH AROUND 2.0 INCH PWATS SHOULD KICK OF SOME
ISOLATED TO SCATTERED THUNDERSTORMS WITH THE BEST CHANCES ALONG AND
NORTH OF I-20 THIS AFTERNOON. THE LOCAL WRF MODEL AND HRRR ALSO
INDICATE THIS..SO WILL UP POPS A TOUCH THIS AFTERNOON FOR THE ABOVE
MENTIONED AREAS. ALSO MADE MINOR ADJUSTMENTS TO TEMPS WITH THE
UPDATES ARE ALREADY OUT./15/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
THE PRIMARY CONCERNS WILL BE THE CONTINUED EXCESSIVE HEAT POTENTIAL
FOR THE REGION THROUGH THE PERIOD AS WELL AS THE POTENTIAL FOR A
FEW SPOTTY STRONG TO SEVERE STORMS.
LATEST SATELLITE IMAGERY SHOWED A MUCH LESS ACTIVE PATTERN THAN WAS
NOTED YESTERDAY MORNING. IT STILL SHOWED A SERIES OF WEAK
DISTURBANCES MOVING FROM THE CENTRAL PLAINS SOUTHEASTWARD THROUGH
THE MISSISSIPPI VALLEY REGION. THIS WAS AROUND THE MEAN MID TO UPPER
LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS. AREA RADARS WERE
PRETTY QUIET ON CONVECTIVE ACTIVITY THIS MORNING. TEMPS ARE DOING A
LITTLE BETTER THIS MORNING IN THE EAST WITH LOWER TO MIDDLE
70S...WHILE THE WEST HALF WAS STILL IN THE UPPER 70S TO LOWER 80S AS
OF 3 AM. A WEAK SURFACE BOUNDARY WAS NOTED ACROSS THE EXTREME NORTH.
A CHALLENGING FORECAST IN THE TOUGH TIMING OF THE DISTURBANCES
COMING DOWN IN NORTHERLY FLOW FOR TODAY THROUGH THURSDAY NIGHT
AROUND THE DOMINANT MID TO UPPER RIDGE CENTERED OVER THE SOUTHERN
PLAINS. MODELS HAVE BEEN HAVING A TOUGH TIME WITH THIS. HAD AN
ISOLATED SEVERE STORM IN THE SOUTHEAST YESTERDAY AFTERNOON. STILL
THINK THAT THE WEAK DISTURBANCES WILL TRIGGER ISOLATED STRONG TO
SEVERE STORMS FOR TODAY...WHICH CAN REALLY FLARE UP DUE TO DAY TIME
HEATING...INSTABILITY...AND STRONG UPPER NORTHERLY FLOW OF 35-45
KNOTS AT 200-300 MB. THE FLOW WILL BE WEAKER ON THURSDAY...BUT STILL
HAVE SOME DECENT INSTABILITY. NORTHWEST FLOW WILL BE MORE PRONOUNCED
ACROSS THE REGION...SO THESE STRONG ISOLATED STORMS COULD OCCUR
ANYWHERE THROUGH TONIGHT. MOISTURE CONVERGENCE WILL BE PRETTY GOOD
ACROSS THE REGION WHERE ANY ISOLATED STORMS DEVELOP. WITH THIS HEAT
WE WILL HAVE GOOD MICROBURST POTENTIAL THE PRIMARY RISK WILL BE
GUSTY WINDS OF 50 TO 60 MPH. THE TIMING OF THESE DISTURBANCES COULD
HAPPEN ANYTIME DURING THE DAY OR NIGHT...WHICH IS EVIDENT BY LATEST
SATELLITE IMAGERY. PWATS WILL BE AROUND 1.5-2.0 INCHES.
AS FAR AS HEAT POTENTIAL IS CONCERN MODELS SHOW THAT THE EXCESSIVE
HEAT POTENTIAL WILL CONTINUE...WITH NO REAL RECOVERY AT NIGHT WITH
LIGHT MOISTURE SOUTHWEST FLOW AT THE SURFACE. THE ONLY EXCEPTION
WILL BE SOME RECOVERY IN THE EAST WITH TEMPS IN THE LOWER TO MIDDLE
70S THIS MORNING. SO WITH THIS IN MIND HAVE OPTED TO LET THE CURRENT
EXCESSIVE HEAT WARNING AND ADVISORY TO EXPIRE AT 8 PM...BUT WILL LET
A HEAT ADVISORY BE IN EFFECT FOR THURSDAY IN THE WEST UNTIL 8 PM.
SO AS FAR AS TEMPS ARE CONCERN ADJUSTED LOWS SLIGHTLY FROM NAM
GUIDANCE WITH LOWS IN THE MID TO UPPER 70S FOR TONIGHT AND THURSDAY
NIGHT. SOME LOCATIONS WILL PROBABLY NOT GET BELOW 80 WITH SUCH HIGH
DEWPOINTS. FOR HIGHS WENT WITH THE CURRENT FORECAST FOR TODAY HIGHS
AND WENT WITH A BLEND OF MAV AND GMOS GUIDANCE FOR THURSDAY. HIGHS
WILL GENERALLY BY IN THE MID 90S TO AROUND 100./17/
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)...
BY THE END OF THE WEEK THE NORTHERLY FLOW ALOFT REGIME THAT`S BEEN
IN PLACE WILL WEAKEN AS UPPER RIDGING TO OUR WEST NOSES IN ACROSS
THE ARKLAMISS IN RESPONSE TO A S/WV TROF DEPARTING THE SE CONUS. THE
RISK OF MCS ACTIVITY DIVING IN FROM THE NORTH WILL LESSEN AS A
RESULT...SHIFTING FOCUS TO MORE OF A DIURNAL SHOWER/THUNDERSTORM
PATTERN TYPICAL FOR THIS TIME OF YEAR. THE OPPRESSIVE HEAT WE`VE
BEEN DEALING WITH LOOKS TO EASE A BIT AS WELL AND IT DOES NOT APPEAR
ANY HEAT HEADLINES WILL BE NECESSARY HEADED INTO THE WEEKEND...
ALTHOUGH AREAS ACROSS THE DELTA MAY FLIRT WITH CRITERIA ON FRIDAY.
RELATIVELY HIGHER RAIN CHANCES LOOK TO DEVELOP SUN/MON AS THE UPPER
RIDGE SHIFTS WEST AND A FRONTAL BOUNDARY ASSOCIATED WITH A CLIPPER
SYSTEM TRANSITING THE NORTHERN CONUS MOVES INTO THE TN VALLEY. IN
ADDITION...AN UPPER TROPOSPHERIC LOW OVER THE FAR SERN CONUS WILL
BEGIN TO SHIFT WEST WITH THE MODELS INDICATING A TRACK SOMEWHERE
ACROSS THE NORTHERN/CENTRAL GULF OF MEXICO. THE COMBINATION OF THESE
FEATURES WITH A WARM AND MOIST ATMOSPHERE IN PLACE SHOULD RESULT IN
DECENT SHOWER/THUNDERSTORM COVERAGE BOTH SUNDAY AND MONDAY
AFTERNOONS. TAME LAPSE RATES AND WEAK OVERALL FLOW SHOULD MITIGATE
THE RISK FOR SEVERE THUNDERSTORMS DURING THIS TIME BUT A FEW STRONG
STORMS IS CERTAINLY NOT OUT OF THE QUESTION. THE INCREASED CHANCE
FOR RAIN WILL HELP KEEP TEMPS A TAD COOLER DURING THIS TIME BUT
STILL EXPECTING READINGS TO COME IN ABOVE NORMAL AT MOST LOCALES.
HEADED INTO TUE/WED...THE GFS IS MUCH MORE AGGRESSIVE PUSHING DRIER
AIR IN WAKE OF THE FRONT INTO CENTRAL MS WHERE THE ECMWF HANGS THE
BOUNDARY UP ACROSS NORTHERN MS. DECIDED TO LEAN MORE ON THE ECMWF
SOLUTION WHICH MEANT A SLIGHT INCREASE IN OVERNIGHT LOWS FOR MON
NIGHT/TUE NIGHT. POPS WERE ADJUSTED A BIT...MOSTLY TO MAINTAIN AT
LEAST A SLIGHT CHANCE ACROSS ALL AREAS WITH BETTER RAIN CHANCES
FURTHER SOUTH. /BK/
&&
.AVIATION...FOCUS FOR THE AFTERNOON WILL BE ON THE ISO/SCT T-STORMS
THAT LOOK TO BE POSSIBLE. AT THIS POINT...WILL INCLUDE A VCTS FOR A
COUPLE SITES TO ACCOUNT FOR THIS. AT THIS TIME...N-CENTRAL AND
CENTRAL PORTIONS MAY HAVE THE BEST RISK FOR THAT. TIMING LOOKS TO BE
AFTER 20-21Z AND TIL 01-02Z. STORMS COULD CONTAIN GUSTY WINDS AND
WILL UTILIZE AMD TO SHOW THOSE IMPACTS IF/WHEN A STORM MAY THREATEN
A SITE. OUTSIDE THAT...THE NGT PERIOD LOOKS TO BE GENERALLY QUIET.
THERE MAY BE SOME SMALL PERIOD OF MVFR VIS AROUND SUNRISE THU
MORNING AND WILL COVER THAT WITH A SMALL PERIOD AT A COUPLE SITES.
/CME/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 98 79 96 77 / 20 22 23 21
MERIDIAN 98 77 96 77 / 20 22 23 23
VICKSBURG 97 79 97 78 / 22 20 23 22
HATTIESBURG 97 79 95 78 / 21 18 23 22
NATCHEZ 95 77 96 76 / 22 19 23 21
GREENVILLE 99 79 97 78 / 22 23 23 23
GREENWOOD 98 78 95 77 / 19 23 23 23
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR
MSZ026>033-036>039- 043>046-048>052-054>058-061>066-072>074.
EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR MSZ018-
019-025-034-035-040-041-047.
HEAT ADVISORY FROM 8 PM THIS EVENING TO 8 PM CDT THURSDAY FOR
MSZ018-019-025-034-035-040-041-047.
HEAT ADVISORY UNTIL 8 PM CDT THURSDAY FOR MSZ042-053-059-060.
LA...EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR
LAZ007>009-015-016-023-025.
HEAT ADVISORY FROM 8 PM THIS EVENING TO 8 PM CDT THURSDAY FOR
LAZ007>009-015-016-023-025.
HEAT ADVISORY UNTIL 8 PM CDT THURSDAY FOR LAZ024-026.
AR...EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR ARZ074-
075.
HEAT ADVISORY FROM 8 PM THIS EVENING TO 8 PM CDT THURSDAY FOR
ARZ074-075.
$$
17/BK
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1124 AM EDT WED AUG 1 2012
.SYNOPSIS...
A WEAK COOL FRONT AND AN AREA OF UPPER LEVEL LOW PRESSURE WILL
KEEP A CHANCE FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST
THROUGH THIS EVENING. HIGH PRESSURE BUILDS IN WITH MAINLY DRY AND
SOMEWHAT WARMER CONDITIONS FOR THURSDAY. ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS IS EXPECTED ON FRIDAY AFTERNOON AS A
WARM FRONT TAKES SHAPE ACROSS NORTH CENTRAL NEW YORK.
&&
.NEAR TERM /THROUGH TONIGHT/...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL WAVE ACROSS THE EASTERN
LAKES THIS MORNING. THE WAVE WAS COINCIDENT WITH MUCH DRIER AIR
ALOFT AND WAS SLOWLY MOVING EAST INTO CENTRAL NY AND NORTHEAST PA.
THE WAVE ALOFT WAS ALSO COINCIDENT WITH A WEAK SFC BOUNDARY. THIS
BOUNDARY WILL WORK EAST THIS AFTERNOON. AT PRESENT THERE WAS A
LOT OF LOW CLOUDS AND STRATUS ACROSS MUCH OF THE REGION. AS THIS
DRIER AIR ALOFT WORKS E IT WILL BREAK UP THE LOWER ST LAYER IN
CONCERT WITH THE DIURNAL HEATING OF THE BNDRY LAYER. ONE CAN SEE
THIS HAPPENING ON THE VISIBLE SATL IMAGERY IN NY AND PA. RADAR WAS
SHOWG SOME ISLD CELLS DEVELOPING OVER THE ROC AREA ALONG THE FRNT.
AS THIS DRY AIR WORKS E AND GETS OUT AHEAD OF THE FRNT...THERE
WILL BE SIGNIFICANT MIXING IN THE BNDRY LAYER AND DESTABILIZATION
THIS AFTERNOON IN ADVANCE OF THE FRNT. MODEL SOUNDINGS FROM THE
NAM AND RUC ARE MOST UNSTABL THIS AFTERNOON WITH PROJECTED MIXED
LAYER CAPES AOA 1000 J/KG. THE GFS...LOCAL WRF AND SREF HAVE LESS
INSTABILITY PROJECTING GENERALLY AROUND 500 J/KG. ALL MODELS HAVE
WEAK WIND FIELDS ALOFT WITH 0-6 KM, 0-3 AND 0-1 KM BULK SHEARS
LESS THAN 10 KNOTS. HOWEVER...THERE WAS A LOT OF DRY AIR ALOFT
ADVECTING EAST AS CONFIRMED ON THE WATER VAPOR IMAGERY AND THE 12Z
BUF AND ESPECIALLY THE 12Z DTX SOUNDING IN SERN LWR MI. IF THE
WEAK FRONT AND WAVE ALOFT CAN ORGANIZE SOME CAPE INTO A LINE OR CLUSTER
OF CELLS...THERE CUD BE AN ISOLATED DOWNBURST OR TWO. BUT...THE
FRONT IS RATHER WEAK AND DIFFUSE AND THE FORCING ALOFT IS NOT
IMPRESSIVE EITHER...SO THIS DRY AIR LIKELY WILL GO AGAINST DEEP
CONVECTION IN THESE AREAS. SO POPS WILL BE LOWER IN THE WESTERN
PART OF THE BGM FORECAST AREA INCLUDING THE FINGER LAKES WHERE THE
DRIER AIR MAKES IT E DURING MAX HEATING.
CONVECTION WILL BE MORE WIDESPREAD IN THE EASTERN PART OF THE BGM
SERVICE AREA WHERE CONVECTION WILL HAVE DEEPER MOISTURE TO TAP
INTO AS THE DRY AIR ALOFT IS NOT PROJECTED TO REACH THESE AREAS
UNTIL 22Z OR LATER...HENCE MOST OF THE CAPE WILL BE REALIZED
BEFORE THIS DRYING ALOFT OCCURS. HENCE PWATS WERE HIGHER AND GIVEN
THE LIGHT WINDS ALOFT...I CUD SEE SOME SLOW MOVING STORMS WITH
LOCALLY HEAVY RAINFALL. I THINK COVERAGE WILL BE HIGHER IN THE
EAST ALSO BECAUSE THERE WILL BE LESS ENTRAINMENT OF DRIER AIR
ALOFT AND SUFFICIENT INSTABILITY. POPS FROM PREVIOUS SHIFT LOOK
FINE.
CONVECTION ALLOWING MESOSCALE MODELS ALL SHOW MORE CONVECTION IN
THE EASTERN PART OF THE BGM CWA THAN IN THE WEST WHICH GO ALONG
WITH THE ABOVE THINKING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ANY CONVECTION THIS EVENING SHOULD WANE OVERNIGHT WITH LOSS OF
HEATING AND GENERAL RIDGING DEVELOPING THROUGH 850 MB. THIS TREND
WILL CONTINUE THROUGH THURSDAY WITHIN A ZONAL FLOW ALOFT AND A
FRONT REMAINING TO OUR WEST. MODELS THEN SUGGEST ANOTHER FRONTAL
SYSTEM MAKING IT`S WAY TOWARD THE REGION ON FRIDAY BUT REMAINING
JUST TO OUR NORTH. INCREASING HEAT AND MOISTURE SOURCES WILL
DECREASE STABILITY WITH ENOUGH WEAK FORCING FROM UPPER WAVES
PASSING THROUGH THE FLOW THAT SCATTERED THUNDERSTORMS SHOULD FORM
FRIDAY AFTERNOON INTO THE EVENING.
TEMPERATURES WARMING UP FOR THURSDAY AND FRIDAY WELL INTO THE 80S
TO NEAR 90 AS WARM SECTOR BECOMES ESTABLISHED AND 850 MB TEMPS
RISE TO 18-20C.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
THE EXTENDED PERIOD BEGINS WITH A ZONAL FLOW ACROSS THE NERN
CONUS, WHILE A JET DIGS INTO THE NORTHERN PLAINS. THIS JET WILL
CARVE OUT A TROF, WHICH WILL SLIDE EASTWARD TOWARD THE GREAT LAKES
EARLY SUNDAY. THE RESULT WILL BE AN UNSETTLED PERIOD, WITH A COLD
FRONT PROGGED TO PUSH INTO NY/PA SUNDAY NIGHT OR
MONDAY...ACCOMPANIED BY THUNDERSTORMS.
DAYTIME MAXES WILL CHALLENGE THE MID TO UPPER 80S ACROSS MUCH OF
THE FA ON SATURDAY...WITH THE LAKE PLAIN APPROACHING 90. AFTER THE
COLD FRONT PASSES...TEMPS WILL RETURN TO NORMAL LEVELS FOR MID WEEK.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS FORECAST, ELM FELL DEEP INTO LIFR TERRITORY THIS MORNING IN
DENSE FOG. THIS WAS THE RESULT OF WET ANTECEDENT CONDITIONS, LIGHT
WIND FLOW AT THE SFC AND ALOFT, AND LOW TDD VALUES. LIGHT FOG
AFFECTED BGM BRIEFLY...OTHERWISE NO RESTRICTIONS ARE BEING
OBSERVED OUTSIDE OF ELM.
MIXING THIS MORNING SHOULD ALLOW ELM TO RECOVER TOWARD VFR
TERRIORY BETWEEN 13Z AND 14Z.
THE REMAINDER OF THE DAY SHOULD BE VFR, BUT THERE IS A CHANCE FOR
SOME ISOLATED THUNDERSTORM ACTIVITY IN THE AFTERNOON. ANY STORM
WHICH DEVELOPS COULD PRODUCE BRIEF MVFR RESTRICTIONS IN DOWNPOURS.
OUTLOOK...
THU THROUGH SUN...MVFR RESTRICTIONS PSBL...IN DIURNALLY DRIVEN
SHRA/TSRA ACTIVITY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/JAB
NEAR TERM...DJN
SHORT TERM...JAB
LONG TERM...DJP
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
725 AM EDT WED AUG 1 2012
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE SOUTHEAST INTO THE
CAROLINAS THROUGH THURSDAY. UPPER LEVEL HIGH PRESSURE WILL THEN
BUILD INTO THE REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...
THIS MORNING...
COMPLICATED UPPER LEVEL FLOW CONTINUES OVER THE REGION WITH
NUMEROUS DISTURBANCES ROTATING THROUGH THE BASE OF THE UPPER LEVEL
TROUGH...WHICH CURRENTLY EXTENDS ALL THE WAY SOUTH INTO SOUTHERN
GA. THE MOST NOTABLE VORTICES WERE LOCATED OVER EASTERN
NC...UPSTATE SC...AND WESTERN VA. RECENT RADAR TRENDS SUGGEST THE
BROKEN LINE OF CONVECTION OVER VA WILL CONTINUE TO MOVE SLOWLY
EASTWARD AND THE OUTFLOW MAY BE THE FOCUS FOR SHOWERS OVER THE
NORTHERN COASTAL PLAIN DURING THE NEXT COUPLE OF HOURS. TO THE
SOUTH... SCATTERED SHOWERS AND A COUPLE THUNDERSTORMS ARE
EXPANDING NORTHWARD OUT OF SC INTO THE SOUTHERN PIEDMONT AND
SANDHILLS. A WEAK LOW PRESSURE CENTER IS FORECAST TO DEVELOP NEAR
THE SAVANNAH RIVER BASIN IN RESPONSE TO THE DPVA APPROACHING A
STALLED OUT...WEAK FRONTAL ZONE OVER THE SC/NC COASTAL REGIONS.
HOWEVER... IT IS HARD TO DETECT AN ACTUAL LOW SO FAR. 00Z RAOBS
FROM KMHX AND KCHS SHOW A FAIR AMOUNT OF ELEVATED INSTABILITY FOR
THE ONGOING SHOWERS TO FEED ON...AND THE HRRR SEEMS TO BE HANDLING
THE TIMING OF THE PRECIP WELL..ALTHOUGH THE RADAR ECHOES EXTEND
FURTHER WEST THAN THE SIMULATIONS. OVER THE NEXT 3-6
HOURS...SCATTERED TO NUMEROUS SHOWERS AND ISOLATED STORMS...ALONG
WITH MORE DEVELOPMENT BACK TO THE SOUTHWEST...SHOULD CONTINUE TO
MOVE TO THE NORTHEAST TO THE EAST OF US HWY 1...WITH MORE ISOLATED
SHOWERS POSSIBLE FURTHER WEST.
WHILE AN AXIS OF AROUND 1000 J/KG OF MUCAPE WILL EXIST THIS
MORNING...THE THREAT IF ANY SEVERE WEATHER IS LOW THROUGH MIDDAY
GIVEN THE WEAK DEEP LAYER FLOW IN THE TROUGH. IF/WHEN THE SURFACE
LOW DEVELOPS AND MOVES NORTHEAST ALONG THE COAST...THE MAY BE A
SHORT WINDOW WHERE LOW LEVEL SHEAR IS ENHANCED...BUT THE 0-1KM AND
0-3KM FLOW JUST LOOKS TOO WEAK FOR THE SMALL TORNADIC CONCERNS THAT
MODELS HAD SHOWN IN PREVIOUS RUNS.
THIS AFTERNOON...
AS THE AXIS OF DEEPER MOISTURE MOVES OFFSHORE...CONVECTION SHOULD
COME TO AN END OVER THE COASTAL PLAIN. ANOTHER UPPER DISTURBANCE
CURRENTLY OVER THE UPPER MIDWEST WILL DIVE INTO THE BACK SIDE OF
THE TROUGH THIS EVENING AND MAY KICK OFF SOME STORMS OVER THE
MOUNTAINS. HOWEVER...MUCH DRIER AIR ALOFT APPROACHING FROM THE
WEST...NOTED ON WATER VAPOR IMAGERY...SHOULD KEEP ANY STORMS
ISOLATED TO WIDELY SCATTERED OVER THE WESTERN PIEDMONT AND MAINLY
AFTER 20Z.
FULL HEATING WOULD SUPPORT HIGHS AROUND 90 TO THE WEST OF US HWY 1
THIS AFTERNOON. TO THE EAST...CLOUD COVER AND SHOWERS ARE GOING TO
LIMIT HEATING THIS MORNING...THOUGH THE EXPECTED DRYING ALOFT AND
THINNING OF CLOUDS FROM THE WEST SHOULD ALLOW MOST AREAS TO REACH
THE MID 80S.
TONIGHT...
OUTSIDE OF THE POTENTIAL FOR A FEW SHOWERS/STORMS MOVING
OFF THE HIGHER TERRAIN TO MAKE IT INTO THE PIEDMONT...CONDITIONS
SHOULD BE RELATIVELY QUIET WITH LOWS IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
THURSDAY AND THURSDAY NIGHT...
A WEAK UPPER LEVEL LOW/SHEAR AXIS IS FORECAST TO BREAK OFF FROM
THE UPPER TROUGH AND SLIP SOUTH TOWARD THE SC COAST ON THURSDAY.
THE FOCUS FOR CONVECTION WILL MAINLY BE ALONG THE COAST...WITH
WEAK ANTICYCLONIC FLOW AND DRIER AIR ALOFT OVER MUCH OF CENTRAL
NC. MAINLY A SLIGHT CHANCE OF SHOWERS/STORMS SOUTH AND EAST OF THE
TRIANGLE DURING THE AFTERNOON. LOW LEVEL THICKNESSES GENERALLY
SUPPORT LOWER 90S AREA WIDE. WITH LITTLE CLOUD COVER
OVERNIGHT...TEMPS SHOULD FALL QUICKLY TO THE UPPER 60S TO LOWER
70S...AND STRATUS/FOG MAY BE AN ISSUE.
FRIDAY AND FRIDAY NIGHT...
THE NAM AND THE GFS ARE FAIRLY CONSISTENT IN FORECASTING A WEAK
UPPER LOW OR SHEAR AXIS TOWARD THE COASTAL PLAIN AND THE CAROLINA
COAST. UNDER A BROAD SOUTHERLY FLOW FROM THE SURFACE THROUGH
850MB...MEAN MOISTURE GRADUALLY INCREASES...AND PRECIPITABLE WATER
VALUES THAT ARE AROUND 1.5 INCHES FRIDAY MORNING ARE FORECAST TO
INCREASE TO AROUND 1.75 INCHES BY 00Z SATURDAY. 250MB WINDS
DIMINISH AND WINDS FROM 850MB THROUGH 500MB ARE LIGHT... ONLY
AROUND 10KT AT BEST...MAKING FOR 0-6KM SHEAR VALUES ALSO AROUND
10KT AT BEST. WEAK LIFT IS FORECAST...BUT MUCH OF CENTRAL NORTH
CAROLINA MAY LIE JUST ON THE WEST SIDE OF THE UPPER LOW OR SHEAR
AXIS...AND NAM AND GFS BUFR SOUNDINGS SHOW A COUPLE OF DEGREES OF
MID- AND UPPER-LEVEL WARMING DURING THE DAY FRIDAY. WITH SLIGHT
MOISTURE ADVECTION...AND SOME UNCERTAINTY IN THE OVERALL LOCATION
OF THE WEAK UPPER-LEVEL FEATURES...THERE SHOULD BE ENOUGH
INSTABILITY... AROUND 1000J/KG OF MLCAPE...THAT A SEA BREEZE IN
THE SOUTHERLY FLOW...FOR EXAMPLE...COULD PROVIDE AN ISOLATED
SHOWER OR THUNDERSTORM. SLIGHT CHANCES WERE IN THE FORECAST AND
WILL NOT REMOVE THOSE...BUT CURRENTLY THINK THAT ISOLATED TO
WIDELY SCATTERED COVERAGE AT BEST WOULD OCCUR FRIDAY AFTERNOON
INTO FRIDAY EVENING.
BOTH THE NAM AND THE GFS PROVIDE FOR LIGHT QPF TOWARD AND WEST OF
THE YADKIN RIVER FRIDAY NIGHT...THOUGH BUFR SOUNDINGS WOULD TEND TO
SUPPORT MORE STABILITY AND THE TYPICAL DIURNAL MIN IN TERMS OF
CHANCES OF RAINFALL. THE GFS...AND TO SOME DEGREE THE NAM...FORECAST
A MODERATELY-STRONG MID-LEVEL SHORTWAVE MOVING INTO THE APPALACHIANS
LATE FRIDAY NIGHT...WHICH MAY BE A RESULT OF CONVECTIVE FEEDBACK.
THE SOUTHERLY 850MB FLOW IS FORECAST BY THE GFS TO STRENGTHEN NEAR
THE MOUNTAINS LATE FRIDAY NIGHT...SO AS THE AIR MASS MOISTENS IT IS
POSSIBLE FOR OVERNIGHT DEVELOPMENT OF SOME DEEP CONVECTION THERE...
THOUGH THE THERMAL WIND WOULD SEEM TO INDICATE A GENERAL MOTION
KEEPING MOST ACTIVITY WEST OF CENTRAL NORTH CAROLINA. WILL NOT
INTRODUCE ANY SLIGHT CHANCES FOR A SHOWER OR THUNDERSTORM OVERNIGHT
FRIDAY...THOUGH TRENDS WILL NEED TO BE WATCHED PARTICULARLY WITH
REGARD TO THE LOCATION AND STRENGTH OF ANY MID-LEVEL WAVE.
1000-850MB THICKNESSES SUPPORT THE SLIGHTLY COOLER MAV GUIDANCE FOR
HIGHS FRIDAY...MAINLY 90 TO 95. LOWS FRIDAY NIGHT AROUND 70.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THERE SEEM TO BE SOME CHANGES IN THE UPPER-AIR PATTERN AS
FORECAST BY THE GFS AND ECMWF...MOST NOTABLY HIGHER HEIGHTS ALOFT
OFFSHORE OF THE MID-ATLANTIC EARLY IN THIS PART OF THE LONG-TERM
PERIOD. AT THE SAME TIME...THE LOW-LEVEL FLOW AROUND BROAD BERMUDA
HIGH PRESSURE IS MORE SOUTHERLY ESPECIALLY EARLY IN THIS PART OF
THE LONG-TERM PERIOD...SUCH THAT THE MEAN AIR MASS IS GENERALLY
MORE MOIST THAN APPARENTLY WAS THE CASE AS FORECAST BY PREVIOUS
GUIDANCE. CERTAINLY THE TREND INTO EARLY NEXT WEEK
CONTINUES...WITH LOWERING HEIGHTS ALOFT AFTER THE WEEKEND AS AN
UPPER TROUGH MOVES EAST ACROSS THE GREAT LAKES AND SOUTHEAST
CANADA...EXTENDING INTO THE MID-ATLANTIC. BOTH THE GFS AND ECMWF
FORECAST A TROUGH AXIS ALOFT MOVING INTO CENTRAL NORTH CAROLINA
WITH A SHEAR AXIS LINGERING INTO TUESDAY. THE DGEX IS ALSO SIMILAR
IN REGARD TO THIS.
ANOTHER CONTINUING TREND OF THE CONSENSUS OF THE GFS AND ECMWF IS
THE GRADUAL INCREASE IN PRECIPITABLE WATER VALUES FROM SATURDAY
THROUGH MONDAY INTO TUESDAY. VALUES AROUND 1.75 INCHES OR SO
SATURDAY CLIMB TO AT OR JUST ABOVE TWO INCHES BY MONDAY AND
CONTINUE FOR THE MOST PART INTO TUESDAY...WITH POSSIBLY SOME
DRYING OVER THE NORTHWEST PIEDMONT LATE ON TUESDAY BASED ON THE
COARSE MODEL SOUNDINGS FROM THE GFS AND ECMWF. FOR THIS FORECAST...
MADE LITTLE CHANGES TO THE PREVIOUS FORECAST IN TERMS OF CHANCES FOR
PRECIPITATION...LOWER CHANCE PROBABILITIES FOR SATURDAY...GRADUALLY
INCREASING TO AROUND 40 PERCENT MONDAY WITH CHANCES CONTINUING
OVERNIGHT MONDAY NIGHT THROUGH TUESDAY NIGHT IN BETTER SYNOPTIC
FORCING ALOFT AS HEIGHTS FALL WITH THE ATTENDANT SHORTWAVE OR SHEAR
AXIS. THE HIGHEST CHANCES WILL BE FORECAST MONDAY...WHEN THERE
SHOULD BE THE BEST MID-LEVEL VORTICITY ADVECTION AND WHERE THE
GUIDANCE FORECASTS THE BEST LIFT. THE GFS HAS TRENDED SLIGHTLY
FASTER WITH THE TROUGH AXIS TUESDAY INTO TUESDAY NIGHT...AND FOR
THEN WILL NOTE HIGHER CHANCES...RELATIVE TO THE REST OF CENTRAL
NORTH CAROLINA...SOUTH AND EAST OF THE TRIAD. 1000-850MB THICKNESSES
HAVE TRENDED LOWER FROM RECENT DAYS IN THIS PART OF THE FORECAST...
AND WILL FORECAST HIGHS WITHIN A DEGREE OR THREE OF 90 SATURDAY
THROUGH MONDAY...THEN 85 TO 90 TUESDAY. OVERNIGHT LOWS WITHIN A
DEGREE OR THREE OF 70 EACH DAY...EXCEPT WARMER MONDAY NIGHT
ANTICIPATING MORE CLOUDS IN A VERY MOIST AIR MASS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 725 AM WEDNESDAY....
SHOWERS AND A FEW ISOLATED THUNDERSTORMS CONTINUE TO MOVE SOUTHWEST
TO NORTHEAST ACROSS THE SANDHILLS AND SOUTHERN COASTAL PLAIN THIS
MORNING...WITH A FEW OF THE SHOWERS IN THE VICINITY OF KFAY.
HOWEVER...LITTLE IMPACT IS EXPECTED OTHER THAN POSSIBLY A BRIEF
PERIOD OF MVFR CEILINGS OR VSBYS THROUGH 15Z. THESE SHOWERS ARE
EXPECTED TO CONTINUE MOVING NORTHEAST ACROSS THE COASTAL PLAIN AND
EVENTUALLY OFFSHORE BY EARLY AFTERNOON. THERE IS SOME UNCERTAINTY
AS TO WHETHER OR NOT THEY WILL DEVELOP AS FAR NORTH AS KRWI AND
KRDU...BUT IF THEY DO THEN A SHOWER/STORM WILL BE POSSIBLY BETWEEN
13-16Z. OUTSIDE OF THESE SHOWERS/STORMS....VFR CONDITIONS ARE
GENERALLY EXPECTED.
LATER THIS AFTERNOON...AN UPPER LEVEL DISTURBANCE APPROACHING FROM
THE NORTHWEST SHOULD TRIGGER SOME STORMS ALONG THE NC/VA
MOUNTAINS...A FEW OF WHICH MAY MOVE SOUTHEAST INTO THE WESTERN
PIEDMONT AFTER 20Z. HOWEVER....THERE IS LOW CONFIDENCE IN EXACTLY IF
OR WHEN KINT/KGSO WOULD BE TERMINAL COULD BE IMPACTED.
LOOKING AHEAD:
AFTERNOON STORMS AND EARLY MORNING STRATUS/FOG WILL BE POSSIBLE EACH
DAY THROUGH THE WEEKEND...WITH A BETTER CHANCE OF STORMS EARLY NEXT
WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/DJF
LONG TERM...DJF
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
316 PM MDT WED AUG 1 2012
.SHORT TERM...THE UPPER LEVEL RIDGE OVER THE TEXAS PANHANDLE WILL
SHIFT FURTHER SOUTH TONIGHT ALLOWING FOR A WEAK WESTERLY FLOW
ALOFT OVER THE REGION ON THURSDAY. THE 16Z HRRR REPRESENTS THE
ONGOING CONVECTION FAIRLY WELL AT THIS TIME. IT ALLOWS FOR THE
MAIN WINDOW OF TSTMS TO MOVE ACROSS THE FOOTHILLS AND URBAN
CORRIDOR THROUGH 00Z AND ACROSS THE NORTHEASTERN PLAINS THROUGH
04Z. THE AMS IS STILL QUITE MOIST WITH PW VALUES AROUND ONE INCH.
WET MICROBURSTS WITH BRIEF HEAVY RAIN...0.5 TO 1 INCH IN 30 MINUTES
AND WIND GUSTS TO 40 KTS. WILL FOLLOW THE TIMING OF THE HRRR
SOLUTION IN THIS EVENINGS PACKAGE. THE AMS IS PROGGED TO STABILIZE
FAIRLY FAST AFTER 04Z. ON THURSDAY...SUBTROPICAL MOISTURE WILL
CONTINUE OVER THE CWFA...WITH SOME SLIGHT DECREASE IN PW VALUES
ADVERTISED WITH THE LOWER LEVELS SLIGHTLY DRIER BELOW 600 MB.
STILL ENUF HOWEVER FOR THE THREAT OF BRIEF HEAVY RAIN SHOWERS.
FCST CAPES ON THE SOUNDINGS IN THE 400-700 J/KG RANGE. WITH THAT
IN MIND...THE SEVERE THREAT WILL BE LOW.
.LONG TERM...NO BIG CHANGES IN FORECAST REASONING THIS TIME
AROUND. IT STILL LOOKS LIKE INCREASING WESTERLY FLOW ACROSS THE
NORTHERN HALF OF THE U.S. WILL BE GOOD ENOUGH TO CUT OFF THE FLOW
OF MONSOONAL MOISTURE FROM THE DESERT SOUTHWEST. IT SEEMS LIKE
FRIDAY IS GOING TO BE THE FIRST DRY DAY OF THE SHORT BREAK FROM
THE MONSOON. WARM TEMPERATURES WILL CONTINUE THROUGH FRIDAY AS NO
CHANGE IN THE LOW LEVEL AIRMASS IS EXPECTED UNTIL SATURDAY
MORNING. THE MOSTLY SUNNY DAY ON FRIDAY WILL ALLOW TEMPERATURES TO
CLIMB BACK INTO THE MID 90S AS THE WEEK DRAWS TO A CLOSE. SAUTRDAY
MORNING WILL BRING A NICE INTRUSION OF COOLER AIR ACROSS THE
FORECAST AREA AS AN UPPER DISTURBANCE CROSSES THE STATE. LOW
TEMPERATURES SATURDAY MORNING MAY DROP INTO THE MID 50S ACROSS THE
PLAINS. THE HUMIDITY LEVELS ASSOCIATED WITH THIS COLD FRONT LOOK
QUESTIONABLE AT THIS POINT...SO I HESITATE TO MENTION TOO MUCH
PRECIPITATION IN THE FOOTHILLS SATURDAY MORNING. SOME AREAS MAY
SEE SOME LIGHT RAIN OR DRIZZLE. BY AFTERNOON...THE AIRMASS BEGINS
DRYING OUT WHILE MODEL SOUNDINGS SHOW THAT A MID LEVEL CAP WILL BE
IN PLACE TO HINDER THE DEVELOPMENT OF ANY SHOWERS. THE ONLY
EXCEPTION TO THIS MIGHT BE THE CENTRAL MOUNTAINS WHERE THE HEATING
OVER THE HIGHER TERRAIN MAY BE ENOUGH TO OVERCOME THE MID-LEVEL
INVERSION. HIGHS ON SATURDAY WILL PROBABLY REMAIN BELOW 90 ACROSS
THE PLAINS. SUNDAY MORNING WILL ALSO BE RELATIVELY CHILLY COMPARED
TO THE PAST FEW WEEKS.
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK...THE MONSOON LOOKS
LIKE IT WILL RE-ESTABLISH ITSELF...AND AFTERNOON THUNDERSTORMS
WILL DEVELOP EACH AFTERNOON. FOR A FEW DAYS AT LEAST...HIGHS WILL
AGAIN BE BACK INTO THE 90S.
&&
.AVIATION...THE PEAK WINDOW FOR TSTMS IN THE DENVER AREA WILL BE
UNTIL THROUGH 00Z THEN THE FOCUS SHOULD SHIFT FURTHER EAST ACROSS
THE ADJACENT PLAINS. BRIEF MVFR CIG AND VSBY RESTRICTIONS POSSIBLE
IF HEAVY RAIN SHOWERS DEVELOP AT THE AIRPORTS. NORTH/NORTHWEST
WINDS WILL TRANSITION TO EAST/SOUTHEASTERLY 01-02Z THEN
SOUTH/SOUTHWESTERLY AFTER 04Z.
&&
.HYDROLOGY...THE MAIN WINDOW FOR TSTMS IN THE FOOTHILLS WILL BE
THROUGH 00Z THEN THE COVERAGE WILL BECOME MORE ISOLATED. BRIEF
HEAVY RAIN THE MAIN ISSUE SO FLASH FLOODING WILL BE A THREAT IN
THE BURN AREAS. THE STRONGER STORMS WILL LIKELY PRODUCE AROUND
0-25-0.50 INCHES IN 30 MINUTES...WITH LESSER CHANCE OF UP TO ONE
INCH. MAIN CONCERN WILL BE TRAINING CELLS SO WILL NEED TO KEEP A
CLOSE EYE ON THAT. TSTMS WITH THE POTENTIAL FOR HEAVY RAINFALL
WILL RETURN THURSDAY AFTERNOON...BUT THE THREAT SHOULD BE SLIGHTLY
LOWER.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....DANKERS
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
157 PM EDT WED AUG 1 2012
.SYNOPSIS...
A WEAKENING COLD FRONT WILL BRING SHOWERS AND THUNDERSTORMS THIS
AFTERNOON...ESPECIALLY TO WESTERN NEW ENGLAND. WARMER AND MORE
HUMID WEATHER IS EXPECTED FOR THE MIDDLE AND END OF THE WEEK ALONG
WITH A LOW CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY LEADING UP
TO MONDAY WHEN A COLD FRNT SLIDES THRU NEW ENGLAND ALONG AND AHEAD
OF WHICH A LINE OF SHOWERS AND THUNDERSTORMS IS EXPECTED.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...
FOG/STRATUS HAS LIFTED AND IS MOVING OFF TO THE EAST. LINGERING
LATE MORNING CLOUDS ESPECIALLY OVER WESTERN AND CENTRAL
SECTIONS. CLEARING IS MOVING IN FROM THE WEST AND WAS REACHING
THE NY/MA BORDER BY 10 AM. BUT WATER VAPOR IMAGERY SHOWS MOIST AIR
OVER EASTERN NY AND WESTERN NEW ENGLAND...SO EXPECT ANY CLEARING
TO FILL IN WITH MORE CLOUDS THIS AFTERNOON.
STABILITY PARAMETERS ARE RATHER MARGINAL FOR THIS
AFTERNOON/EVENING. TOTALS CLIMB TO THE MID 40S...LI FALLS TO
AROUND -3...SURFACE BASED CAPE VALUES 500-800 J/KG. ALL OF THIS
POINTS TO SOME SUPPORT FOR SCATTERED TSTMS BUT QUESTIONABLE FOR
DAMAGING STORMS. PARAMETERS ARE MORE PRONOUNCED OVER EASTERN AND
CENTRAL NY/PA WITH TOTALS 50-52...LI OF -6...SBCAPE 1500-2000
J/KG...AND A THETA-E RIDGE FROM THE ADIRONDAKS TO CENTRAL PA.
PRECIPITABLE WATER VALUES ARE 1.5 TO 1.8 INCHES...SO ANY
SHOWERS/STORMS THAT FORM WOULD HAVE POTENTIAL FOR HEAVY DOWNPOURS.
STORM MOTION FROM THE 12Z ALB SOUNDING IS FROM THE WEST AT 11
KNOTS...WHICH WOULD MEAN THE HEAVY DOWNPOURS WOULD SLOWLY MOVE OUT
OF AN AREA. SO POTENTIAL FOR URBAN/POOR DRAINAGE FLOODING.
PUT IT ALL TOGETHER...HIGHEST POPS WEST AND LOWEST EAST THIS
AFTERNOON/EVENING WITH SHOWERS/TSTMS AND HEAVY DOWNPOURS.
TEMPS/DEWPOINTS GRIDS ARE ON TARGET SO NO CHANGES PLANNED TO THOSE
FORECASTS.
PREVIOUS DISCUSSION...
MAIN CONCERN FOR TODAY IS DEVELOPMENT OF SHOWERS/STORMS AS MID
LEVEL TROUGH AND WEAKENING COLD FRONT HEAD E FROM GREAT LAKES.
AIRMASS REMAINS UNSTABLE TO OUR W ACROSS PA WHERE STORMS HAVE
MAINTAINED THEMSELVES MOST OF THE NIGHT. 3KM HRRR BRINGS SOME OF
THIS WEAKENING ACTIVITY INTO WESTERN NEW ENGLAND AROUND 10 AM.
AFTER THAT DEVELOPMENT OF ADDITIONAL CONVECTION WILL DEPEND ON HOW
MUCH INSTABILITY CAN BE GENERATED. 00Z MODELS CONTINUE TO INDICATE
MORE FAVORABLE CONDITIONS WILL REMAIN TO OUR W THIS AFTERNOON...
BUT MARGINAL INSTABILITY COMBINED WITH WEAK CONVERGENCE ALONG
FRONT AND PLENTY OF LOW LEVEL MOISTURE SHOULD GENERATE MORE
SHOWERS AND STORMS ACROSS WESTERN NEW ENGLAND. SEVERE WEATHER
THREAT REMAINS LOW DUE TO WEAK MID LEVEL LAPSE RATES AND WEAK WIND
FIELDS ALOFT.
TOUGH CALL ON FORECAST HIGHS GIVEN UNCERTAINTY WITH CLOUD COVER
TODAY. LOWERED HIGHS SLIGHTLY WITH BLEND OF GFS/NAM MOS...IN 70S
TO MID 80S WITH WARMEST READINGS ACROSS INTERIOR EASTERN MA.
WEAK PRESSURE GRADIENT SHOULD ALLOW SEA BREEZES TO DEVELOP LATER
THIS MORNING. ALSO OF NOTE IS MODERATE RISK OF RIP CURRENTS WHICH
IS BEING FORECAST FOR CAPE COD AND ISLANDS AS WELL AS E MA COAST
TODAY. THIS IS DUE TO WIND WAVES OF 6-8 FT OFFSHORE TRANSITIONING
INTO E/SE SWELL.
&&
.SHORT TERM /THURSDAY/...
ANY CONVECTION SHOULD DIMINISH THIS EVENING ALBEIT SLOWLY AS
PLENTY OF LOW LEVEL MOISTURE REMAINS IN PLACE. EXPECT RETURN OF
PATCHY LOW CLOUDS AND FOG...ESPECIALLY NEAR COAST WITH LIGHT S/SW
FLOW.
CHANCES FOR SHOWERS/STORMS THU IS LOWER THAN TODAY DESPITE
CONTINUED PRESENCE OF MID LEVEL TROUGH. CROSS SECTIONS SHOW SOME
DRIER AIR WORKING IN ALOFT WHICH SHOULD LIMIT OVERALL CONVECTIVE
POTENTIAL. NONETHELESS WITH S/SW FLOW PROVIDING PLENTY OF LOW
LEVEL MOISTURE AND WEAK BOUNDARY NEARBY...INCLUDED ISOLATED
SHOWERS/STORMS ACROSS INTERIOR THU AFTERNOON. ONCE AGAIN SEVERE
THREAT IS VERY LOW.
ANOTHER LOW IS EXPECTED TO EMERGE OFF CAROLINAS BUT UPPER FLOW IS
PROGRESSIVE ENOUGH TO ALLOW THIS SYSTEM TO PASS WELL SE OF NEW
ENGLAND THU AFTERNOON.
NAM/GFS MOS CLOSE TONIGHT AND THU SO CONTINUED TO RUN WITH A BLEND
OF BOTH. SHOULD COME CLOSE TO 90 THU AFTERNOON IN PARTS OF PIONEER
AND MERRIMACK VALLEYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* HOT AND HUMID CONDITIONS FOR THE END OF THE WEEK INTO THE WEEKEND
* DIURNALLY DRIVEN STORMS PSBL FRIDAY AND SATURDAY
* QUIET WX FOR SUNDAY...COLD FRNT WITH SHOWERS AND THUNDERSTORMS MONDAY
* COOLER AND DRIER WX PSBL BEYOND MONDAY
MODEL DIAGNOSIS...
GENERAL AGREEMENT AMONGST FCST SOLNS CONTINUES TO BE EXHIBITED WITH
INITIAL 01/0Z MODEL GUIDANCE. ONLY SCRUTINY IS A SLIGHTLY FASTER H5
TROF DISTURBANCE ALONG THE US-CANADIAN BORDER AROUND 12Z SATURDAY...
YET BRIEFLY PER 01/0Z GFS WITH THE H5 TROF SLOWING IN ITS APPROACH
EWD AGAINST THE WRN ATLANTIC RIDGE INTO THE END OF THE WEEKEND. THIS
IS NOT SEEN THOUGH IN THE 01/0Z UKMET. AM LEFT TO CONSIDER GREATER
WEIGHT TOWARDS EUROPEAN FCST GUIDANCE...BUT WILL BLEND GFS/NAM FCST
GUIDANCE ACCORDINGLY.
THEREAFTER THERE IS SERIOUS DOUBT WITH THE 01/0Z GFS INVOKING A DEEP
CLOSED LOW ACROSS CENTRAL CANADA GOING AGAINST ITS RESPECTIVE 31/12Z
ENSEMBLE OUTPUT. YET THERE IS SOME UNCERTAINTY WITH THE 31/12Z ECMWF
USHERING THE SRN PLAINS/SRN ROCKIES H5 RIDGE EWD. GLOBAL ENSEMBLE
FCST GUIDANCE IN AGREEMENT OF A NEGATIVE NAO PATTERN FOR THE FIRST
WEEK OF AUGUST...BUT SOLNS BECOME DIVERSE AND THERE IS A LARGE AMNT
OF SPREAD BEYOND. AM EXPECTING A GENERAL TROF PATTERN FOR THE NERN
CONUS INTO THE EARLY PORTION OF NEXT WEEK WITH CONTINUED POS HEIGHT
ANOMALIES AND RIDGING OVER THE WRN ATLANTIC NWD INTO GREENLAND. AS
TO WHETHER THE TROF PATTERN CONTINUES...OR RATHER BREAKS DOWN...
AFTER THE FIRST WEEK OF AUGUST IS FAIRLY UNCERTAIN. AM NOT GIVING
MUCH CONSIDERATION TO THE FCST TUESDAY /7TH/ AND BEYOND.
THURSDAY NIGHT INTO FRIDAY NIGHT...
THE DEPARTURE OF THURS SYSTEM DRAWS WARM MOIST AIR NWD ALONG AND
AHEAD INVOKING POS HEIGHT RISES THRU THE WRN ATLANTIC AND
STRENGTHENING THE BERMUDA HIGH. SUBSEQUENTLY...W/SWLY FLOW IS
ENHANCED ACROSS NEW ENGLAND UNDER A MORE ZONAL FLOW REGIME THEREBY
DRAWING WARM AND MOIST AIR NEWD. MDL FCST SOUNDINGS EXHIBIT CAPPING
AROUND H85 WITH A FAIR AMNT OF ELEVATED INSTABILITY. THERE ARE
SUBTLE HINTS OF WEAK ENERGY ADVECTING THRU THE ZONAL FLOW REGIME
DURING THE DAY FRIDAY...AND WITH THAT BEING SAID THERE IS THE
PLAUSIBILITY OF CONVECTION FORCED VIA CYCLONIC FLOW AND ENHANCED
ASCENT THRU THE CAPPING INVERSION. HEAVY RAIN WILL REMAIN A THREAT
WITH PWAT VALUES AROUND 1.5 INCHES. FEEL ANY CONVECTION WILL BE
ISOLATED /GREATER CHCS ACROSS THE INTERIOR/. AM NOT THINKING
ANYTHING SEVERE. LOOKING AT A VERY HOT AND HUMID DAY FRIDAY.
SATURDAY INTO SATURDAY NIGHT...
FCST GUIDANCE SUGGESTS AN ATTENDANT WEAK WARM FRNTL BOUNDARY PARENT
WITH THE SFC LOW AND H5 TROF ACROSS THE GRT LKS WILL BE THE FOCUS
FOR DIURNALLY FORCED CONVECTION. CAPPING INVERSION AROUND H85 IS
STILL APPARENT AND A STRENGTHENING BERMUDA HIGH TOWARDS THE ERN
CONUS RESULTS IN THE INTRUSION OF DRIER AIR THRU THE MID-LVLS. YET
HEIGHT FALLS ARE EXPECTED ACROSS THE WRN INTERIOR WITH THE APPROACH
OF THE H5 TROF AXIS...AND SHOULD SOME SFC CONVERGENCE PREVAIL ALONG
THE WEAK WARM FRNTL BOUNDARY...FEEL THE WRN INTERIOR WILL HAVE CHC
FOR SHOWERS AND THUNDERSTORMS. NOT COMPLETELY SOLD ON THE OUTCOME...
ITS PSBL THE PERIOD MAY TURN OUT DRY. IF ANY POPS...SLGT CHC. HOT
AND HUMID CONDITIONS CONTINUE FOR THE INTERIOR...COOLER NEAR THE
SHORES.
SUNDAY INTO MONDAY...
SUNDAY APPEARS THE BETTER OF THE TWO DAYS WITH THE RGN FINDING
ITSELF WITHIN THE WARM SECTOR AHEAD OF THE APPROACHING TROF AXIS AND
ATTENDANT COLD FRNT. ANY FORCING MAY BE WELL N OF THE FCST AREA.
OTHERWISE THE MAIN SHOW PREVAILS FOR MONDAY AS A COLD FRNT WITH
SHOWERS AND THUNDERSTORMS SWEEPS THRU THE RGN. AM VERY CONCERNED
WITH THE POSSIBILITY OF HEAVY RAIN AND FLASH FLOODING AS PWATS ARE
ADVERTISED AROUND 2 INCHES /IN SOME CASES 2.5/. NOT CERTAIN STORMS
WILL BE SEVERE /PARAMETERS OF SHEAR APPEAR WEAK WITH MODEST
INSTABILITY THOUGH SKINNY AND THIN THRU THE ATMOS COLUMN/.
TUESDAY AND BEYOND...
WILL PREVAIL A DRY FCST FOR NOW. AS NOTED BY THE PREV FORECASTER...
THE STRONGER WRN ATLANTIC RIDGE MAY SLOW THE PROGRESSION OF THE COLD
FRNT ON MONDAY THEREBY RESULTING IN ACTIVE WX TO LINGER INTO TUE. AS
IT STANDS PRESENTLY...FCST GUIDANCE IS QUICK TO MOVE THE SYS
OFFSHORE AND USHER ACROSS THE RGN COOLER AND DRIER HIGH PRES. WILL
PREVAIL AS SUCH.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
THIS AFTERNOON...MODERATE CONFIDENCE
RADAR SHOWS SEVERAL SHOWERS MOVING NORTHEAST THROUGH NORTHERN CT
AND CENTRAL MASS. A SHOWER ALSO POPPED NEAR BOSTON ALONG THE SEA
BREEZE FRONT. EXPECT THIS ACTIVITY TO CONTINUE THROUGH THE EVENING
WHILE FAVORABLE INSTABILITY IS IN PLACE. CIGS ARE GENERALLY AROUND
3500 FEET BUT DIP TO 2500 FEET IN PLACES. SO EXPECT LOW-END
VFR...POSSIBLY BRIEF MVFR IN SHOWERS. SEA BREEZES CONTINUE ALONG
THE COAST THROUGH SUNSET.
TONIGHT...LOW CONFIDENCE
LINGERING CLOUDS OVERNIGHT WITH SOME LIGHT FOG POSSIBLE AFTER
MIDNIGHT. BEST POTENTIAL FOR DENSE FOG WOULD BE AT NANTUCKET. MOST
FOG OVERNIGHT WOULD BE MVFR...WITH IFR IN A FEW SPOTS.
THURSDAY...MODERATE CONFIDENCE
GENERALLY VFR. CLEARING SKIES IN THE MORNING. DIURNAL CLOUDS THEN
DEVELOP. CONDITIONS MARGINAL FOR SCATTERED SHOWERS/TSTMS BUT MAY
BE ISOLATED SHOWERS/STORMS. BRIEF MVFR IN ANY PRECIP.
THURSDAY NIGHT...MODERATE CONFIDENCE.
VFR EARLY. AREAS OF IFR IN FOG AFTER MIDNIGHT.
KBOS TAF...MODERATE CONFIDENCE.
VFR WITH SEA BREEZE. SCATTERED TO WIDELY SCATTERED SHOWERS MAY
DEVELOP ALONG SEA BREEZE IN THE VICINITY OF THE AIRPORT WITH MVFR
CIGS/VSBYS IN ANY PCPN. VFR TONIGHT WITH POTENTIAL FOR MVFR VSBYS
IN FOG LATE AT NIGHT. VFR THURSDAY WITH ISOLATED TSTMS POSSIBLE IN
THE AFTERNOON...MVFR IN ANY PCPN THAT DOES FORM.
KBDL TAF...MODERATE CONFIDENCE.
VFR THIS AFTERNOON/EVENING WITH BRIEF MVFR CIGS/VSBYS IN ANY TSTMS
THAT MOVE THROUGH. ANY STORMS SHOULD BE SLOW MOVING...AND SO LOCALLY
HEAVY DOWNPOURS ARE POSSIBLE WITH IFR CONDITIONS. VFR TONIGHT
WITH POTENTIAL FOR MVFR VSBYS IN PATCHY FOG LATE AT NIGHT. VFR
THURSDAY WITH ISOLATED TSTMS AND RESULTING BRIEF MVFR CIGS/VSBYS.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY INTO FRIDAY NIGHT... PSBL CONVECTION FRI ACROSS THE
INTERIOR...LOW CONFIDENCE. OTHERWISE PREVAIL VFR WITH MODEST
W/SWLY FLOW. GUSTS OVER SHORELINE TERMINALS AROUND 20 KTS.
SATURDAY INTO SATURDAY NIGHT...
RENEWED CHCS FOR SHRA/TSRA ACROSS THE INTERIOR...LOW CONFIDENCE. SLY
FLOW WITH GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
COLD FRNT APPROACHES WITH SHRA/TSRA ALONG AND AHEAD. SUNDAY VFR WITH
INCREASING SLY FLOW /GUSTS AROUND 20 KTS/. SHOULD REMAIN DRY.
MONDAY...SHRA/TSRA EXPECTED CLEARING LATE INTO TUE MORN.
&&
.MARINE...
WEAKER WINDS THIS AFTERNOON AS SURFACE LOW HEADS OUT TO SEA.
AFTERNOON SEA BREEZES EXPECTED. S/SW FLOW PREVAILS TONIGHT AND
THU WITH PATCHY LATE NIGHT AND EARLY MORNING FOG.
LOW PRESSURE SHOULD PASS WELL S AND E OF NEW ENGLAND THU BUT WE
MAY SEE SEAS OF 5-6 FT REACH OUTER WATERS.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY NIGHT...
W/SWLY FLOW BECOMING SLY WITH GUSTS AROUND 20 KTS FOR THE S WATERS
WILL INVOKE SEAS OF 5 FT ALL THE WAY INTO THE LOCAL SOUNDS AND BAYS.
NOT EXPECTING ANY STORMS.
SATURDAY INTO SATURDAY NIGHT...
SLY FLOW WILL REMAIN BRISK BUT WEAKER ENOUGH TO ALLOW SWELL TO
DIMINISH. GUSTS AROUND 15 KTS.
SUNDAY INTO MONDAY...
SLY FLOW INCREASING INTO SUNDAY IN RESPONSE TO APPROACHING COLD
FRNT. SEAS BUILDING ALONG THE S AND E WATERS IN RESPONSE. COLD FRNT
TO SLIDE ACROSS THE WATERS LATE MONDAY ALONG AND AHEAD OF WHICH
SHOWERS AND THUNDERSTORMS ARE EXPECTED AND LIKELY TO LINGER INTO THE
TUE MORN HRS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SIPPRELL/JWD
NEAR TERM...WTB/SIPPRELL/JWD
SHORT TERM...JWD
LONG TERM...SIPPRELL
AVIATION...WTB/SIPPRELL
MARINE...SIPPRELL/JWD/WTB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 PM MDT WED AUG 1 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 225 PM MDT WED AUG 1 2012
THROUGH TONIGHT...CONVECTION IS ONCE AGAIN EXPECTED TO DEVELOP
ACROSS THE PALMER DIVIDE REGION OF COLORADO WITH A GRADUAL SHIFT
EASTWARD WITH TIME. HRRR IS ALSO DEVELOPING CONVECTION ACROSS
NORTHWEST KANSAS BUT GIVEN LACK OF CU DEVELOPMENT OVER THIS
AREA...CONFIDENCE IS BELOW AVERAGE IN THIS SOLUTION. HAVING SAID
THAT...WILL MAINTAIN SLIGHT CHANCE POPS TO COVER THIS POTENTIAL. DID
BUMP POPS UP SLIGHTLY FOR THE LATE EVENING TIME FRAME WHEN
CONFIDENCE IS HIGHEST.
TRENDED OVERNIGHT LOWS UP OVER THE EAST SIMILAR TO WHAT WAS OBSERVED
THIS MORNING. OTHERWISE...LIGHT AND VARIABLE WINDS WITH A GRADUALLY
CLEARING SKY ARE EXPECTED.
THURSDAY...MAX TEMPS WILL BE SLIGHTLY COOLER AS COMPARED WITH TODAY
WITH HIGHS IN MOST LOCATIONS REMAINING IN THE MID 90S TO AROUND 100
DEGREES. POTENTIAL EXISTS ONCE AGAIN FOR CONVECTION DEVELOPING
DURING THE LATE AFTERNOON HOURS. GIVEN OBSERVED PWAT VALUES AROUND
135 PERCENT OF NORMAL...LOCALLY HEAVY RAINFALL WILL ONCE AGAIN BE A
THREAT. GUSTY OUTFLOW WINDS ALSO APPEAR TO BE POSSIBLE BASED ON
POINT SOUNDINGS FROM ACROSS THE AREA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 225 PM MDT WED AUG 1 2012
THURSDAY NIGHT-SATURDAY...FAIRLY ACTIVE WEATHER WILL CONTINUE
THROUGH THE PERIOD AS STRONG SHORT WAVE TROUGH DIVES INTO THE
NORTHERN PLAINS...FORCING STRONG COLD FRONT INTO THE TRI STATE AREA
FRIDAY NIGHT AND SATURDAY...BRINGING SOME RELIEF FROM THE HEAT TO
THE AREA BY SATURDAY AFTERNOON. NOT REAL CONFIDENT IN PRECIPITATION
CHANCES ON THURSDAY EVENING WITH MAIN STATIONARY FRONT WELL TO THE
SOUTH OF THE AREA AND LOW LEVEL FLOW BEING LIGHT AND GENERALLY
WESTERLY. HOWEVER...PERIOD OF LARGE SCALE ASCENT WILL MOVE JUST
NORTH OF THE CWA AND IF THE MUCH WEAKER CINH PROFILE OF THE NAM
VERIFIES...THAT MAY BE ENOUGH TO INITIATE AT LEAST A FEW STORMS
ALONG SFC TROUGH THAT EXTENDS INTO WESTERN CWA. GIVEN ABOVE CONCERNS
AND SREF DATA REALLY FOCUSING BEST CHANCES NEAR FRONT DO NOT THINK
OVERALL PATTERN REALLY WARRANTS MORE THAN 15-20 PERCENT. THINK BEST
CHANCES FOR PRECIPITATION WILL BE DURING THE OVERNIGHT HOURS ON
FRIDAY AS STRONG COLD FRONT SWEEPS ACROSS THE AREA...WHICH WILL NOT
ONLY BRING A PERIOD OF STRONG NEAR SFC ASCENT BUT A PERIOD OF DEEPER
ASCENT DEEP DIRECT CIRCULATION EXPECTED TO DEVELOP BEHIND FRONT
COLOCATED WITH AREA OF LARGE SCALE ASCENT AS PER Q VECTOR ANALYSIS.
WHILE FORCING WILL LIKELY BE THE STRONGEST ITS BEEN OUT OF THE PAST
SEVERAL DAYS...STILL A LARGE AMOUNT OF UNCERTAINTY WITH RESPECT TO
HOW MUCH INSTABILITY WILL BE AHEAD AND BEHIND FRONTAL ZONE AS
EVIDENCED BY LARGE DIFFERENCES BETWEEN GEFS AND SREF PROBABILISTIC
OUTPUT...AND THINK FOR THE TIME BEING THINK KEEPING POPS BELOW 50
PERCENT WARRANTED ATTM.
IN THE EXTENDED (SAT NIGHT-WEDNESDAY)...WHILE 06Z ROUND OF ENSEMBLES
SHOWED LITTLE SPREAD IN OVERALL PATTERN STARTING TO SEE A BIT MORE
UNCERTAINTY DEVELOP WITH RESPECT TO STRENGTH OF H5 RIDGE EXPECTED TO
DEVELOP OVER THE ROCKIES THROUGH THE MIDDLE OF NEXT WEEK. SOME
ENSEMBLES SEEM TO BE CLUSTERING TOWARDS BOTH THE MORE AMPLIFIED GFS
WITH THE OTHERS MORE IN THE ECMWF CAMP WHICH CERTAINLY LOWERS
CONFIDENCE IN TRYING TO PICK ONE MODEL OVER THE OTHER. FOR THE TIME
BEING...THINK CONSENSUS APPROACH THE BEST BET FOR HIGH TEMPS FOR THE
TIME BEING. TEMPERATURES WILL GRADUALLY WARM THROUGH THE
PERIOD...BUT WITH POSSIBILITY OF CWA BEING ON NORTHEAST SIDE OF A
FAIRLY AMPLIFIED RIDGE POTENTIAL FOR COOLER AIR BACKING INTO THE AREA
KEEPS CONFIDENCE TOO LOW TO MAKE LARGE DEVIATIONS FOR MAX TEMPS. FOR
LOWS...WITH SFC HIGH SETTLING OVER THE AREA ON SAT NIGHT BEHIND
STRONG COLD FRONT AND AT LEAST A FEW HOURS OF LIGHT WINDS AND MUCH
DRIER AIR COULD SEE FAIRLY CHILLY LOWS ACROSS MUCH OF THE CWA WITH
VALUES IN THE MID TO UPPER 50S. PRECIP CHANCES DO NOT LOOK
PARTICULARLY GREAT THROUGH THE PERIOD BOTH DUE TO MORE STABLE AIR
MOVING IN BEHIND THE FRONT AND THEN WITH STRONG RIDGE DEVELOPING
NEAR THE AREA. LEFT A FEW AREAS SMALL CHANCES...ESPECIALLY ON SAT
DUE TO FRONTAL TIMING CONCERNS AND AGAIN ON WEDNESDAY AS GEFS DATA
BRINGING FAIRLY HIGH PROBABILITIES OF MEASURABLE PRECIP OVERNIGHT
TUES INTO WED MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1203 PM MDT WED AUG 1 2012
ANTICIPATE PRIMARILY VFR CONDITIONS OVER THE NEXT 24 HOURS AT BOTH
KGLD AND KMCK. CONVECTION SHOULD DEVELOP ACROSS THE HIGHER TERRAIN
OF EASTERN COLORADO LATE THIS AFTERNOON. QUESTIONS REMAIN AS TO
JUST HOW FAR EAST THIS PRECIP WILL MAKE IT. MAY SEE A FEW STORMS
DEVELOP ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA AFTER 22Z
BUT THESE SHOULD REMAIN AWAY FROM THE TERMINALS. WILL CARRY VCTS
FOR KGLD AFTER 03Z WITH VCSH FOR KMCK AFTER 04Z. CAN`T COMPLETELY
RULE OUT A BRIEF PERIOD OF MVFR VSBY SHOULD A HEAVIER STORM
DIRECTLY IMPACT A TERMINAL.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...FOLTZ
LONG TERM...JRM
AVIATION...FOLTZ
AREA FORECAST DISCUSSION
NWS JACKSON KY
151 PM EDT WED AUG 1 2012
.UPDATE...
ISSUED AT 150 PM EDT WED AUG 1 2012
FRESHENED UP THE TEMPERATURE AND DEW POINT TRENDS TO BETTER MATCH THE
CURRENT OBSERVATIONAL TRENDS. OTHERWISE...NO UPDATE IS PLANNED.
UPDATE ISSUED AT 1057 AM EDT WED AUG 1 2012
MORNING CONVECTION DIMINISHED BETWEEN 9 AND 10 AM...AS SCHEDULED.
TEMPERATURES CAME IN COOLER THIS MORNING COMPARED TO TUESDAY
MORNING...AND THIS HAS HAMPERED THE DIURNAL RISE SO FAR. HAVE LOWERED
THE HIGHS A TOUCH TO ACCOUNT FOR THIS TREND...BUT GENERALLY MOST
LOCATIONS WILL STILL SEE AROUND 90. A WEAK STATIONARY FRONT REMAINS
DRAPED FROM JUST SOUTH OF A LINE FROM KEVV...TO KSDF...TO KILN.
ANOTHER SHORT WAVE TROUGH...CURRENTLY MOVING SOUTHEAST ACROSS INDIANA
WILL ALSO MOVE INTO EASTERN KENTUCKY THIS AFTERNOON. GIVEN THESE TWO
FEATURES...HAVE GONE AHEAD AND INCLUDED SLIGHT CHANCE POPS FOR ALL.
THE HRRR HAS BEEN GENERATING SOME CONVECTION ACROSS MOST OF THE
AREA...ALTHOUGH THE 06 AND 12Z NAM RUNS HAVE REMAINED DRY. THE
FORECAST SOUNDINGS HAVE TRENDED A BIT WEAKER WITH THE CAP THIS
AFTERNOON...AND THERE IS PLENTY OF DRY AIR ALOFT...WITH MUCH LOWER
WET-BULB ZERO HEIGHTS TODAY. WILL HAVE TO WATCH FOR A FEW PULSERS
THAT CAN TAKE ADVANTAGE OF THIS ENVIRONMENT.
UPDATE ISSUED AT 750 AM EDT WED AUG 1 2012
UPDATED THE GRIDS...MINORLY...TO BETTER REFLECT POPS EARLY THIS
MORNING. ALSO TWEAKED SKY...T AND TD GRIDS FOR CURRENT OBS AND
TRENDS. UPDATES HAVE BEEN SENT TO NDFD AND THE WEB.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 335 AM EDT WED AUG 1 2012
06Z SFC ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE LAYING ACROSS THE
NORTHWEST PORTION OF EASTERN KENTUCKY...RELATED TO A MINOR COLD FRONT
THAT IS PASSING THROUGH THE AREA EARLY THIS MORNING. THIS HAS JUST
RECENTLY HELPED TO TRIGGER A FEW CELLS OF CONVECTION IN THE WESTERN
PARTS OF THE CUMBERLAND VALLEY...DRIFTING SOUTHEAST INTO THE
SOUTHERN INTERSTATE 75 CORRIDOR. ON SATELLITE...THE CLOUDS HAVE
INCREASED DURING THE PAST COUPLE OF HOURS IN RESPONSE TO THE
BOUNDARY AND SOME ENERGY PASSING THROUGH AT MID LEVELS. THE CLOUDS
WILL HELP TO LIMIT ANY FURTHER DROP IN TEMPERATURES THROUGH THE REST
OF THE NIGHT. AS IT STANDS...A MINOR RIDGE TO VALLEY TEMPERATURE
SPLIT ON THE ORDER OF ABOUT 5 DEGREES EXISTS OUT THERE...MAINLY IN
THE NORTHEAST AS OF 3 AM EDT. LOW DEW POINT DEPRESSIONS ARE ALSO
FOUND IN THE VALLEYS AND ANY PLACE THAT MANAGE TO STAY MOSTLY CLEAR
CAN EXPECT PATCHY FOG IN THE VALLEYS TOWARD DAWN...POSSIBLY DENSE IN
LOCATIONS CLOSER TO THE VIRGINIA BORDER THAT SAW SOME DECENT RAINS ON
TUESDAY AFTERNOON.
THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT WITH THE MAIN FEATURES
AFFECTING THE SHORT TERM FORECAST. THEY AGREE THAT STRONG RIDGING
WILL REMAIN PARKED OFF TO THE SOUTHWEST OF THE AREA...IN NORTHERN
TEXAS...AND THAT THE EASTERN THIRD OF THE NATION WILL BE IN BROAD
TROUGHING...DOWNSTREAM OF THE RIDGE. LOCALLY...EAST KENTUCKY WILL BE
UNDER THE INFLUENCE OF NORTHWEST FLOW WITH A COUPLE OF WEAK
SHORTWAVES PASSING OVERHEAD INTO THURSDAY. ONE OF THESE WAVES IS
PASSING THIS MORNING AND IS PARTIALLY RESPONSIBLE FOR THE CURRENT
CONVECTION IMPACTING OUR WESTERNMOST COUNTIES. THE NEXT WILL COME
THROUGH THIS EVENING AND SHOULD BRING AN UPTICK IN CONVECTIVE
POTENTIAL TO THE AREA...THOUGH ITS BEST INFLUENCE WILL LIKELY BE FELT
FURTHER TO THE EAST. TOWARD THE END OF THE PERIOD...THE PATTERN
BECOMES MORE ZONAL AS THE EASTERN TROUGH STARTS TO FLATTEN OUT AND
THE WESTERN RIDGE SHIFTS SOUTH. GIVEN THE MODEL SIMILARITIES HAVE
FOLLOWED A BLENDED SOLUTION WITH A STRONG LEAN TOWARD THE HIGHER
RESOLUTION NAM12 OUTSIDE OF THE NEXT 12 HOURS...WHEN THE HRRR IS
PREFERRED.
SENSIBLE WEATHER WILL FEATURE THE CURRENT CONVECTION WINDING DOWN
LATER THIS MORNING IN THE SOUTH WITH BUILDING INSTABILITY POSSIBLY
HELPING TO KICK OFF SOME MORE IN THE FAR EAST LATER IN THE
AFTERNOON...SIMILAR TO WHAT OCCURRED ON TUESDAY. THIS SHOULD BE THE
LAST THREAT OF CONVECTION THROUGH THE SHORT TERM...THOUGH...AS
LIMITED UPPER LEVEL SUPPORT AND WEAK SFC HIGH PRESSURE WILL LIKELY
SUPPRESS CONVECTION AFTER 00Z TONIGHT. AS SUCH...WE CAN EXPECT
ANOTHER WARM AND HUMID COUPLE OF DAYS WITH HEAT INDICES MAXING OUT
BETWEEN 95 AND 100 DEGREES EACH AFTERNOON. WILL MENTION THIS IN THE
FORTHCOMING HWO. AT NIGHT...PATCHY VALLEY FOG WILL BE THE NORM WITH A
SMALL RIDGE TO VALLEY TEMPERATURE SPLIT EACH NIGHT AS TEMPERATURES
AND DEWPOINTS KEEP A MUGGINESS IN THE AIR...AND PATCHY FOG IN THE
VALLEYS TOWARD DAWN.
FOLLOWED A BLEND OF PERSISTENCE...EXISTING GRIDS...AND THE LATEST
MET GUIDANCE FOR TEMPERATURES THROUGH THE SHORT TERM. AS FOR POPS...
ENDED UP JUST ON THE HIGH SIDE OF GUIDANCE TODAY AND IN LINE WITH IT
FOR TONIGHT AND THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 355 AM EDT WED AUG 1 2012
OVERALL...THE LONG TERM LOOKS TO BE UNSETTLED WITH QUITE A BIT OF
RAIN POTENTIAL OVER THE PERIOD. A BERMUDA HIGH IS EXPECTED TO BE
STRENGTHENING OVER THE ERN U.S. WHILE AN AREA OF LOW PRESSURE GAINS
MOMENTUM OVER CANADIAN PRAIRIES BENEATH A RELATIVELY ZONAL FLOW
ALOFT OVER THE OHIO VALLEY TO START THE PERIOD. RETURN FLOW IS
EXPECTED TO BE UNDER WAY BY FRIDAY...USHERING AMPLE MOISTURE BACK
INTO THE REGION WITH PWATS PROGGED TO BE AROUND 2 INCHES FROM LATE
FRIDAY THROUGH SUNDAY AFTERNOON.
GUIDANCE CONTINUES TO POINT TOWARDS A COUPLE OF SHORT WAVES SKIRTING
THE AREA AROUND THE FRIDAY/SATURDAY TIME FRAME. THE LATEST GFS ALONG
WITH THE GEM ARE STILL ADVERTISING A RATHER POTENT WAVE REACHING THE
TN VALLEY ON FRIDAY IN CONJUNCTION WITH MODEST ISENTROPIC LIFT AT
H85 OVER ERN KY DURING THE AFTERNOON. STILL NOT CONFIDENT ENOUGH TO
GO HIGHER THAN CHANCE AT THIS POINT BUT ANOTHER ROUND OF OFFERINGS
WITH THE SAME SOLUTIONS SHOULD WARRANT A BUMP UP TO LIKELY POPS FOR
AT LEAST PART OF THE CWA ON FRIDAY. SATURDAY IS LOOKING SIMILAR TO
FRIDAY...THOUGH WITH LESS IN THE WAY OF SHORT WAVE TRIGGERS...BUT
ATTAINABLE FCST CONVECTIVE TEMPS IN THE LOWER 80S ALONG WITH ANY
REMNANT BOUNDARIES FROM FRIDAY MAY BE ENOUGH TO GET THINGS GOING
BEFORE OUTFLOW PROCESSES TAKE OVER.
FOCUS THEN SHIFTS TO AN ALBERTA CLIPPER SYSTEM MOVING THROUGH THE
UPPER MIDWEST AND INTO THE GREAT LAKES ON SUNDAY. THE MODELS
CONTINUE TO COME INTO BETTER ALIGNMENT WITH THE TIMING OF THE SYSTEM
OVERALL. FORCING ASSOCIATED WITH THE COLD FRONT LOOKS TO BEGIN
APPROACHING THE AREA ON SUNDAY WITH SHOWERS AND THUNDERSTORMS
OVERSPREADING THE AREA DURING THE AFTERNOON AND EVENING BEFORE UPPER
LEVEL SUPPORT ARRIVES SUNDAY NIGHT INTO MONDAY. MODELS STILL SUGGEST
THE FRONT STALLING OVER THE AREA ON MONDAY AND DESPITE WHAT SHOULD
BE DIMINISHING MOISTURE BY THAT POINT...WILL KEEP CHANCE POPS FOR
MONDAY TO ACCOUNT FOR MODELS TENDENCIES TO BE A LITTLE FAST IN
MOVING THINGS OUT TOO QUICKLY THIS FAR OUT.
GIVEN THE INCREASING AGREEMENT AMONG THE MODELS...STAYED FAIRLY
CLOSE TO THE CONSENSUS NUMBERS FOR TEMPS THROUGHOUT THE PERIOD. THIS
RESULTED IN HIGHS ON FRIDAY AND SATURDAY RUNNING ABOVE NORMAL
BEFORE SLIDING BACK TOWARDS CLIMO FROM SUNDAY ONWARD. AFTER A MODEST
RIDGE/VALLEY SPLIT THURSDAY NIGHT...LOWS LOOK TO REMAIN WITHIN REACH
OF NORMAL THROUGHOUT THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 150 PM EDT WED AUG 1 2012
EXPECT SOME ISOLATED CONVECTION TO POP UP THROUGH THE REST OF THIS
AFTERNOON BEFORE DISSIPATING BY DUSK. ANY STORMS WILL BRING IFR
CONDITIONS OR WORSE...BUT GENERALLY LESS THAN 15 MINUTES OVER A GIVEN
LOCATION. GIVEN THE ISOLATED COVERAGE...WILL CONTINUE TO NOT MENTION
THESE AT THE TAF SITES. FOG WILL LIKELY FORM IN THE VALLEYS
TONIGHT...AND HAVE INCLUDED TEMPORARY IFR CONDITIONS FOR LOZ AND
SME...OTHERWISE VFR CONDITIONS WILL PREVAIL THE MAJORITY OF THE TIME
THROUGH THE PERIOD. WEST WINDS BETWEEN 5 AND 10 KTS WILL BECOME
LIGHT AND VARIABLE BY DUSK.
STRAY CONVECTION CONTINUES TO SPARSELY AFFECT THE AREA EARLY THIS
MORNING. THIS SHOULD CLEAR UP BY 14Z. OTHERWISE...VFR CONDITIONS WILL
DOMINATE THROUGH THE PERIOD. EXPECT TO SEE SOME PATCHY DENSE VALLEY
FOG LATE TONIGHT AND INTO EARLY THURSDAY MORNING...BUT THE MAIN TAF
SITES SHOULD REMAIN CLEAR. OUTSIDE OF ANY STRAY THUNDERSTORMS
TODAY...THE WINDS WILL BE LIGHT AND VARIABLE THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...GREIF
LONG TERM....MB
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1124 AM CDT WED AUG 1 2012
.DISCUSSION...
MOSTLY SUNNY WEST WITH LOWER 90S...TO PARTLY TO MOSTLY CLOUDY FOR
A SOME ZONE GROUPINGS NORTH AND EAST WITH MID TO UPPER 80S.
LOOKING UPSTREAM STILL SOME MORE CLOUDS TO FILTER DOWN ACROSS S AR
INTO N LA...SO HAVE EASED DOWN HIGH TEMPS A DEGREE OR FEW HERE AND
THERE...BUT NOTHING TOO DIFFERENT FROM HOT. THE HEAT ADVISORY
CONTINUES AREA WIDE WITH HX AROUND 105 OR MORE IN SPOTS. WE HAVE
PEARED BACK A BIT ON THE WESTERN EXTENT OF SLIGHT CHANCE FOR REST
OF TODAY...AND IT WAS LEANING THAT WAY ALREADY...THIS JUST MAKES
FOR LESS WORDING AS THE TEXT FORECAST TRANSITIONS FROM MORNING TO
AFTERNOON WORDING. THE LATEST RAP AND NAM MODELS SHOWING NO QPF
FOR THE CWA...BUT GFS AND EURO BOTH CONSENTED TO A SLIGHT CHANCE
EARLIER. ONE THING IS FOR SURE THE RAINFALL OF CHANCE FOR ANYWAY IS
GETTING CLOSER AS THE UPPER RIDGE IS ALL BUT SHUNTED WEST OF THE
MISSISSIPPI RIVER LOOKING AT THE LATEST WATER VAPOR IMAGERY. /24/
&&
.AVIATION...
VFR CONDITIONS EXPECTED THIS AFTERNOON AND TONIGHT ACROSS THE AREA.
TERMINALS HAVE MAINTAINED VFR STATUS THIS MORNING...WITH ONLY KLFK
BRIEFLY DROPPING TO MVFR AS SOME LOW CLOUDS BRIEFLY PASSED OVER.
WINDS WILL BE PRIMARILY OUT OF THE SOUTH TODAY...IN THE 5 TO 10 KNOT
RANGE WITH A FEW HIGHER GUSTS POSSIBLE. A FEW THUNDERSTORMS MAY BE
POSSIBLE FROM KELD TO KMLU THIS AFTERNOON. WITH CONFIDENCE NOT VERY
HIGH IN COVERAGE...HAVE ADDED VCTS TO WORDING. OTHERWISE...SCATTERED
AFTERNOON CU WILL DEVELOP IN THE 5KFT RANGE. /20/
&&
.PREV DISCUSSION... /ISSUED 713 AM CDT WED AUG 1 2012/
DISCUSSION...
A FEW SHOWERS HAVE DEVELOPED AND MOVED INTO SE OK/SW AR. PRODUCTS
ARE ALREADY OUT ON A QUICK UPDATE TO EXTEND 20 POPS FURTHER WWD
TODAY TO COVER THE ONGOING SHOWERS. /12/
PREV DISCUSSION... /ISSUED 349 AM CDT WED AUG 1 2012/
DISCUSSION...
ANOTHER HOT ONE IS ON TAP FOR TODAY...AS THE UPPER RIDGE CONTINUES
TO HOLD STRONG OVER NRN TX. MODELS INDICATE SOME WEAKNESS ALONG
THE ERN PERIPHERY...WHICH MAY BRING SOME CONVECTION ACROSS N LA/SW
AR TODAY. HAVE KEPT THE CURRENT HEAT ADVISORY IN TACT ACROSS THE
ENTIRE REGION...AS HEAT INDICES LOOK TO RUN 103-108 AREAWIDE. WE
MAY SEE SOME ISOLATED 110-112 HEAT INDICES ACROSS THE E...BUT WILL
NOT GO WITH THE EXCESSIVE HEAT WARNING DUE TO THE ANTICIPATED
SHORT DURATION AND ISOLATED NATURE. MIXING MAY KEEP A FEW SITES IN
THE W FROM REACHING THE 105 DEGREE THRESHOLD...BUT AGAIN...THIS
SHOULD BE VERY ISOLATED AND DOESN`T WARRANT KEEPING THESE AREAS
OUT OF THE ADVISORY. THU IS ALSO SHAPING UP TO BE SIMILAR TO
TODAY...SO HAVE EXTENDED THE HEAT ADVISORY ONE MORE DAY.
CONTINUED WEAKNESS ON THE ERN SIDE OF THE RIDGE WILL KEEP SLIGHT
CHANCE POPS IN THROUGH THE REMAINDER OF THE WORK WEEK AND INTO THE
WEEKEND. A WEAK COLD FRONT ASSOCIATED WITH A TROF OVER THE GREAT
LAKES REGION IS FCST TO BEGIN BACK-DOORING INTO THE REGION BY
SUNDAY...ADDING RAIN CHANCES FOR THE ENTIRE REGION...AND ALSO
BREAKING THE HEAT TO SOME EXTENT. THE PRESENCE OF THE BOUNDARY
WILL KEEP THOSE RAIN CHANCES IN FOR THE REMAINDER OF THE PD...AND
KEEP TEMPS CLOSER TO NORMAL. /12/
AVIATION...
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE NEXT 24 HOURS.
ISOLATED CONVECTION MAY DEVELOP MID TO LATE AFTERNOON ACROSS SOUTH
CENTRAL ARKANSAS INTO NORTH CENTRAL LOUISIANA...BUT COVERAGE TOO
SMALL TO MENTION IN KELD OR KMLU TERMINAL FORECAST AT THIS TIME.
SURFACE WIND ACROSS THE REGION MOSTLY SOUTH TO SOUTHWEST 5 TO 10
KTS. /14/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 101 77 100 78 100 / 20 10 10 10 10
MLU 100 80 100 78 99 / 20 20 20 20 20
DEQ 101 72 102 73 102 / 20 10 10 10 10
TXK 101 78 101 77 101 / 20 10 10 10 10
ELD 98 78 100 76 99 / 20 20 20 20 20
TYR 102 78 102 79 100 / 10 10 10 10 10
GGG 102 77 101 78 101 / 10 10 10 10 10
LFK 99 76 99 76 98 / 10 10 10 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR THE FOLLOWING ZONES:
ARZ050-051-059>061-070>073.
LA...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR THE FOLLOWING ZONES:
LAZ001>006-010>014-017>022.
OK...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR THE FOLLOWING ZONES:
OKZ077.
TX...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR THE FOLLOWING ZONES:
TXZ096-097-108>112-124>126-136>138-149>153-165>167.
&&
$$
24/20
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
317 PM EDT WED AUG 1 2012
.SYNOPSIS...
EXPECT ANY REMAINING THUNDERSTORMS TO END EARLY TONIGHT. HIGH
PRESSURE WILL PROVIDE DRY AND VERY WARM CONDITIONS THURSDAY AND
FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
RECENT SURFACE AND RADAR DATA SHOW SCATTERED THUNDERSTORMS ACROSS
THE APPALACHIAN MOUNTAINS, AND NO MORE THAN ISOLATED STORMS ELSEWHERE.
PER RECENT HRRR MODEL OUTPUT, EXPECT THIS WILL BE THE TREND INTO
EARLY EVENING.
FOR THE REST OF THE NIGHT, NOCTURNAL COOLING AND THE UPPER TROUGH
EXITING EAST WILL STABILIZE CONDITIONS. NAM MODEL PROFILES SHOW A
STRONG, SHALLOW SURFACE TEMPERATURE, WHICH CAN RESULT IN PATCHY
FOG, PERHAPS MORE WIDESPREAD IN THE RIVER VALLEYS.
FORECASTED TEMPERATURES, USING RECENT GFS AND NAM MOS, THAT
PROJECTED LOWS TONIGHT TO BE NEAR NORMAL, AS SURFACE DEW POINTS
ALSO LOWER TO NEAR NORMAL VALUES. HIGHS THURSDAY AFTERNOON CAN BE
5 DEGREES WARMER THAN NORMAL, WHILE SURFACE DEW POINTS WILL REMAIN
CLOSE TO NORMAL.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
SREF MODEL OUTPUT CONTINUES TO SHOW HIGH PRESSURE WILL BRING DRY
WEATHER FOR THURSDAY AND FRIDAY.
FORECASTED TEMPERATURES TO BE WARMER THAN NORMAL, WITH AFTERNOON
HIGHS THURSDAY WELL INTO THE 80S AND HIGHS FRIDAY IN THE LOWER 90S
ACROSS LOWER ELEVATIONS. EARLY MORNING LOWS WILL BE SLIGHTLY
WARMER THAN NORMAL, AS SOUTHERLY WINDS BRING INCREASING HUMIDITY
AS INDICATED BY SURFACE DEW POINTS IN THE MID TO UPPER 60S BY
FRIDAY.
AS THE NEXT EASTBOUND CANADIAN LOW PRESSURE SYSTEM NEARS THE GREAT
LAKES SATURDAY, HAVE CONTINUED A CHANCE OF THUNDERSTORMS SATURDAY.
INCREASED CLOUDS MAY RESTRICT AFTERNOON HIGH TEMPERATURES FROM
BEING AS WARM AS FRIDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
CONSENSUS OF MODELS SHOWS A CLOSED UPPER LOW AND SURFACE LOW
TRACKING NORTH OF THE GREAT LAKES INTO SOUTHERN QUEBEC BY MONDAY.
INSTABILITY WILL BE INCREASED AS ALREADY HUMID CONDITIONS WILL BE
FURTHER AUGMENTED BY LOW LEVEL SOUTHERLY WINDS PROVIDING AN
ADDITIONAL INFLUX OF GULF MOISTURE. SO EXPECT SCATTERED
THUNDERSTORMS TO CONTINUE ACROSS THE UPPER OHIO VALLEY THROUGH EARLY
MONDAY.
SPC HAS INDICATED SOME POTENTIAL FOR SEVERE STORMS SUNDAY DUE TO
INCREASED VERTICAL SHEAR.
SURFACE HIGH PRESSURE IS PROGGED TO BUILD IN AND PROVIDE DRY AND
STABLE CONDITIONS TUESDAY AND WEDNESDAY.
FORECAST TEMPERATURES WILL REMAIN AT LEAST SLIGHTLY WARMER THAN
NORMAL BASED ON BLEND OF RECENT GFS AND ECMWF MOS AND NAEFS MEDIAN
VALUES.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
EXPECT MAINLY VFR INTO EARLY TONIGHT, ALTHOUGH ISOLATED
THUNDERSTORMS MAY CAUSE BRIEF RESTRICTIONS. NO MENTION WAS INCLUDED
IN TAFS AS CONFIDENCE OF OCCURRENCE REMAINS LOW FOR ANY GIVEN
LOCATION.
EXPECT AREAS OF IFR FOG DEVELOP LATE TONIGHT MAINLY AFTER 08Z AS
SURFACE INVERSION SETS UP WITH LIGHT SURFACE WINDS. FOG SHOULD
QUICKLY BURN OFF WITH STRONG SUN THURSDAY MORNING.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
EXPECT VFR AND GENERALLY DRY CONDITIONS FOR THURSDAY NIGHT AND
FRIDAY. RESTRICTIONS WILL BE POSSIBLE AGAIN WITH THUNDERSTORMS
SATURDAY AND SUNDAY...AS ANOTHER LOW PRESSURE SYSTEM MOVES ACROSS THE
GREAT LAKES INTO SOUTHERN QUEBEC AND PUSHES A COLD FRONT THROUGH THE
REGION. SURFACE HIGH PRESSURE SHOULD BRING IMPROVEMENT TO VFR MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
252 PM EDT WED AUG 1 2012
.SYNOPSIS...
A PASSING WEAK UPPER LEVEL DISTURBANCE WILL SUPPORT THUNDERSTORM
CHANCES THROUGH EARLY EVENING. HIGH PRESSURE WILL BRING DRY AND
VERY WARM CONDITIONS THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
RECENT SURFACE AND RADAR DATA SHOW SCATTERED THUNDERSTORMS ACROSS
THE APPALACHIAN MOUNTAINS, AND NO MORE THAN ISOLATED ELSEWHERE.
PER RECENT HRRR MODEL OUTPUT, EXPECT THIS WILL BE THE TREND INTO
EARLY EVENING.
FOR THE REST OF THEN NIGHT, NOCTURNAL COOLING AND THE UPPER
TROUGH EXITING EAST WILL STABILIZE CONDITIONS. NAM MODEL PROFILES
SHOW A STRONG, SHALLOW SURFACE TEMPERATURE, WHICH CAN RESULT IN
PATCHY FOG, PERHAPS MORE WIDESPREAD IN THE RIVER VALLEYS.
FORECASTED TEMPERATURES TO AGAIN BE SLIGHTLY WARMER THAN NORMAL,
BASED ON RECENT GFS AND NAM MOS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
HIGH PRESSURE WILL BRING DRY WEATHER AND FOR THURSDAY AND FRIDAY.
FORECASTED TEMPERATURES TO CONTINUE WARMER THAN NORMAL, WITH AFTERNOON
HIGHS THURSDAY AND FRIDAY WELL INTO THE 80S. EARLY MORNING LOWS WILL
BE SLIGHTLY WARMER THAN NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONTINUED HUMID AND VERY WARM CONDITIONS WILL EVOLVE INTO UNSETTLED
CONDITIONS THIS PERIOD.
CONSENSUS OF MODELS SHOW A STRONG UPPER LEVEL TROUGH AND CLOSED
SURFACE LOW TRACKING, EAST ALONG THE CANADIAN BORDER THIS WEEKEND
THAT WILL PASS EASTWARD THROUGH THE EASTERN GREAT LAKES MONDAY.
INSTABILITY WILL BE INCREASED AS ALREADY HUMID CONDITIONS WILL BE
FURTHER AUGMENTED BY LOW LEVEL SOUTHERLY WINDS PROVIDING AN
ADDITIONAL INFLUX OF GULF MOISTURE. SO EXPECT A DECENT CHANCE OF
THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY THIS WEEKEND.
SURFACE HIGH PRESSURE IS PROGGED TO PROVIDE DRY, STABLE CONDITIONS
TUESDAY.
FORECAST TEMPERATURES TO CONTINUE AT LEAST SLIGHTLY WARMER THAN
NORMAL BASED ON BLEND OF RECENT GFS AND ECMWF MOS AND NAEFS MEDIAN
VALUES.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
EXPECT MAINLY VFR INTO EARLY TONIGHT, ALTHOUGH ISOLATED
THUNDERSTORMS MAY CAUSE BRIEF RESTRICTIONS. NO MENTION WAS INCLUDED
IN TAFS AS CONFIDENCE OF OCCURRENCE REMAINS LOW FOR ANY GIVEN
LOCATION.
EXPECT AREAS OF IFR FOG DEVELOP LATE TONIGHT MAINLY AFTER 08Z AS
SURFACE INVERSION SETS UP WITH LIGHT SURFACE WINDS. FOG SHOULD
QUICKLY BURN OFF WITH STRONG SUN THURSDAY MORNING.
OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
EXPECT VFR AND GENERALLY DRY CONDITIONS FOR THURSDAY NIGHT AND
FRIDAY. RESTRICTIONS WILL BE POSSIBLE AGAIN WITH THUNDERSTORMS
SATURDAY AND SUNDAY...AS ANOTHER LOW PRESSURE SYSTEM MOVES ACROSS THE
GREAT LAKES INTO SOUTHERN QUEBEC AND PUSHES A COLD FRONT THROUGH THE
REGION. SURFACE HIGH PRESSURE SHOULD BRING IMPROVEMENT TO VFR MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
128 PM EDT WED AUG 1 2012
.SYNOPSIS...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL DRIFT THROUGH THE GREAT LAKES REGION TODAY...
BRINGING SEASONABLY WARM AND DRY CONDITIONS. MEANWHILE...THE NEXT
LOW PRESSURE SYSTEM AND COOL FRONT...WILL MIGRATE ALONG THE CANADIAN
BORDER. THIS LOW WILL MOVE THROUGH TONIGHT...WITH ITS TRAILING COOL
FRONT SLIDING THROUGH THURSDAY. SCATTERED SHOWERS AND STORMS...WILL
ACCOMPANY THIS FRONT. HIGH PRESSURE WILL BUILD IN FROM THE NORTH
FRIDAY...BUT THE COOL FRONT WILL BECOME STATIONARY...JUST SOUTH OF
THE REGION...WITH NORTHERN PLAINS LOW PRESSURE APPROACHING FROM THE
WEST. THE NEXT CHANCE OF RAIN...WILL APPROACH WITH THIS SYSTEM OVER
THE WEEKEND.
&&
.UPDATE...
ISSUED AT 128 PM EDT WED AUG 1 2012
SPECTACULAR START TO THE MONTH OF AUGUST WELL UNDERWAY WITH HIGH
PRESSURE OVERHEAD. NO CHANGES MADE TO GOING FORECAST...WITH JUST
SOME CU DEVELOPMENT NEAR THE IMMEDIATE COASTLINES. WATCHING
UPSTREAM CONVECTIVE DEVELOPING ON THE FRINGE OF PRONOUNCED
MOISTURE RETURN AND STEEP MID LEVEL LAPSE RATE ENVIRONMENT. THIS
WILL BE OUR MAIN ISSUE HEADING INTO THE EVENING AND OVERNIGHT.
MORE ON THAT IN A BIT...
UPDATE ISSUED AT 907 AM EDT WED AUG 1 2012
GOING TO BE A BEAUTIFUL DAY ALL THROUGHOUT NORTHERN MICHIGAN
TODAY...COURTESY OF LOW/MID LEVEL RIDGE AXIS DIRECTLY OVERHEAD.
STILL WATCHING THE EVOLUTION OF SOME PESKY STRATUS ACROSS
NORTHEAST LOWER INTO LAKE HURON WITHIN RESIDUAL LOW LEVEL MOISTURE
AXIS BENEATH A VERY SHARP NEAR-SURFACE INVERSION. PER TRENDS NOTED
YESTERDAY AND THE NATURE OF THESE THINGS...WILL LIKELY SEE THIS
CLOUD BAND HANG ON FOR A FEW MORE HOURS AND HAVE ADJUSTED THE
CLOUD FORECAST AS SUCH. HOWEVER...EARLY AUGUST SUN SHOULD WORK ITS
MAGIC BY LATE MORNING...HELPING RAPIDLY ERODE SAID CLOUD DECK BY
AROUND 16Z AT THE LATEST.
HAVE ALSO SEEN QUITE A BIT OF FOG OVERNIGHT AS EXPECTED...BUT THIS
TOO IS ON THE WAY OUT. QUITE DRY AIRMASS (12Z APX RAOB PWAT WAS
JUST 0.42 INCHES!) DUE OVERHEAD COMBINED WITH INCREASED MIXING
SHOULD SEND DEW POINTS PLUMMETING FOR INLAND LOCATIONS INTO THE
AFTERNOON...AND PER TRENDS UPSTREAM YESTERDAY AND STRONG
GUIDANCE/FORECAST RAOB HINTS...HAVE LOWERED READINGS DOWN INTO THE
40S. THIS WILL RESULT IN MINIMUM RH VALUES DOWN IN THE MID
20S...BUT WITH LIGHT WINDS AND RECENT WIDESPREAD RAIN...NO FIRE
CONCERNS EXPECTED. OUTSIDE OF THAT...GOING HIGHS WELL INTO THE 80S
LOOK JUST FINE. OVERALL A GREAT START TO THE MONTH...ENJOY!
UPDATE ISSUED AT 646 AM EDT WED AUG 1 2012
BAND OF STRATUS HAS DEVELOPED OVER THE LAST HOUR OR SO ACROSS NE
LOWER AND INTERIOR EASTERN UPPER...WHILE SHALLOW GROUND FOG
CONTINUED IN MANY LOW LYING AREAS. BOTH OF THESE WILL MIX
OUT/ERODE OVER THE NEXT COUPLE OF HOURS AS DAYTIME HEATING MIXES
IN SOME QUITE DRY AIR THROUGH 700MB. ALSO HAD TO COOL THE LOWEST
LYING AREAS WHICH DROPPED INTO THE MIDDLE/UPPER 40S. OTHERWISE THE
FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 348 AM EDT WED AUG 1 2012
TROUGHING OVER THE EASTERN COUNTRY AND AN UPPER RIDGE OVER THE
PLAINS...LEADS TO CONTINUED NW FLOW ALOFT INTO THE GREAT LAKES.
ONE SHORTWAVE IS WORKING ACROSS SRN ONTARIO AND IS ASSOCIATED
WITH AN AREA OF INCREASED UPPER LEVEL MOISTURE SEEN ON LATEST WV
IMAGERY. THIS FEATURE IS RUNNING INTO SOME MINOR UPPER RIDGING
OVER NRN MICHIGAN AND ASSOCIATED CLOUDS IN THE HIGHER LEVELS HAS
BEEN WANING WITH TIME. A STRONGER MORE DEFINED SHORTWAVE IS SEEN
IN MANITOBA ALSO PER SATELLITE DATA...AND IN RUC ANALYSIS FOCUSED
AROUND 700MB. THIS WAVE IS WORKING ON A WARM FRONT EXTENDING EAST
FROM A SFC LOW IN SRN MANITOBA. MAXIMUM LOW LEVEL CONVERGENCE
ASSOCIATED WITH A LLJ POINTING INTO THIS REGION AND WESTERN ONTARIO
HAS RESULTED IN AN MCS WITH A SWATH OF SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS. SKIES ARE CLEAR HERE...WITH ONLY SOME PATCHY HIGH
LEVEL CLOUDS SCRAPING EASTERN UPPER. ALTHOUGH SFC BASED MOISTURE
LINGERS IN THE NORTH WOODS (TDS IN THE 50S AND EVEN LOW 60S)...THE
LOW LEVEL MOISTURE PROFILE SHOWS DRYING FROM ALOFT. THIS HAS HELD
FOG DEVELOPMENT IN CHECK FROM AN AERIAL PERSPECTIVE.
TODAY...NO CONCERNS. HIGH PRESSURE AND LIGHT WINDS CURRENTLY OVER
THE FAR WESTERN GREAT LAKES WILL GRADUALLY WORK IN OVER THE SW
CWA/GTV BAY REGION THROUGH THE DAY. THIS WILL BRING A RETURN TO
SOUTHERLY WINDS THAT INCREASE MORE SO ACROSS EASTERN UPPER. A
LIGHTER WIND REGIME ACROSS NRN LOWER WILL LEAD TO THE DEVELOPMENT
OF LAKE BREEZES AND CONVERGENCE ACROSS NE LOWER. ONE WOULD TEND TO
BELIEVE THAT CUMULUS WILL BE MORE SO CONFINED TO THIS AREA.
HOWEVER...THE LOW LEVEL AIR MASS PROFILE (GENERALLY 700MB AND
BELOW)...IS QUITE DRY. CUMULUS WILL BE HARD TO COME BY WITH MAYBE
JUST SOME STRANDS OF CIRRUS OVERHEAD. A TRULY DECENT SUMMERTIME
DAY WITH TEMPERATURES IN THE WARMER SOUTHERLY FLOW RISING INTO THE
MID AND UPPER 80S ALL AREAS...OUTSIDE OF ONSHORE FLOW CREATED BY
MESOSCALE LAKE BREEZE/ONSHORE FLOW.
BY TONIGHT...THE LOW PRESSURE FROM MANITOBA WILL HAVE SHIFTED
ACROSS SRN MANITOBA...WITH A PRE-FRONTAL TROUGH/COLD FRONT AND
AXIS OF HIGHER THETA-E AIR TO LAY ACROSS EASTERN UPPER IN THE LATE
EVENING...AND ULTIMATELY IN NRN LOWER OVERNIGHT. THE UPPER WAVE
BECOMES SLIGHTLY MORE SHARP TONIGHT...AND THE THETA-E AIR
INCREASES IN THE EVENING BEFORE LOWERING OVERNIGHT...AS
CONVERGENCE ALONG THE TROUGH/COLD FRONT WANES IN THE DEPARTURE OF
THE SHORTWAVE ALOFT. FROM A PATTERN PERSPECTIVE...APPEARS AS
THOUGH THIS SCENARIO LEADS TO BEST CHANCES FOR SEEING
PRECIPITATION WILL BE ACROSS EASTERN UPPER AND FAR NRN LOWER
MICHIGAN WHEN FORCING IS MAXIMIZED WITH GREATEST MOISTURE/WARMTH
AND INSTABILITY (MUCAPES NEARING 1200 J/KG). POPS WILL DECREASE
NEARER THE SAGINAW BAY AS THE SHORTWAVE FORCING AND LOW LEVEL
CONVERGENCE MAXIMUMS DON`T QUITE REACH. REGARDLESS...THE BOUNDARY
DOES WORK THROUGH THIS AREA AS WELL. THE PRECIPITATION PICTURE
BEING PAINTED HERE IS FOR BEST/AND MOST PROLONGED CHANCE FOR
SEEING SHOWERS AND STORMS IN THE NRN HALF OF THE CWA. WILL KEEP
TREND OF ONLY 40% CHANCE THERE WITH 30% FURTHER SOUTH. JUST HAVE
TOO MANY CONCERNS REVOLVING AROUND ANTECEDENT RELATIVELY DRY AIR
MASS...ESPECIALLY THE LOW LEVELS WHICH DON`T EXACTLY DON`T BLOW MY
MIND IN A MOISTURE ADVECTION PERSPECTIVE. THIS FURTHER SUPPORTED
BY LACK OF/NO FGEN IN THE H8-H5 LAYER. ALL-IN-ALL...THIS IS
SEEMINGLY A LACKLUSTER EFFORT FOR PRECIPITATION. CAN FORESEE A HIT
AND MISS SHOWERY IDEA NORTH...WITH DECAYING/LESS AREAL COVERAGE
FURTHER SOUTH INTO THE PRE-DAWN HOURS HOURS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 348 AM EDT WED AUG 1 2012
NORTHERN HEMISPHERIC LARGE SCALE PATTERN CONFIGURATION ENSURES
CURRENT NOAM PATTERN IN NO HURRY TO CHANGE ANYTIME SOON...PLACING
THE NORTHERN LAKES IN PERSISTENT...AND AT TIMES ACTIVE...NORTHWEST
FLOW REGIME THROUGH THE REMAINDER OF THE WORK WEEK. CONSISTENT MID
RANGE GUIDANCE SUPPORT FOR SOME RELAXATION IN EASTERN NOAM TROUGHING
OVER THE WEEKEND...ALLOWING RATHER POTENT SHORTWAVE TO DIVE INTO THE
NORTHERN PLAINS...FORCING DOWNSTREAM HEIGHT RISES AND MORE
IMPRESSIVE SURGE OF LOW LEVEL MOISTURE INTO THE REGION. THIS SETS
THE STAGE FOR A POTENTIALLY ACTIVE (SEVERE WEATHER?) WEEKEND AS SAID
WAVES PLOWS THROUGH A SEASONABLY MOIST...INCREASINGLY UNSTABLE
AIRMASS. IN LIGHT OF THE ABOVE...FORECAST CONCERNS CENTER ON
MULTI-PERIOD PRECIP POTENTIAL...AS WELL AS TEMPERATURE AND CLOUD
TRENDS THROUGHOUT.
START OF THE PERIOD SHAPING UP TO BE SOMEWHAT ACTIVE AS LOW
AMPLITUDE WAVE AND ATTENDANT SURFACE LOW DRAG A SLOW MOVING COLD
FRONT SOUTH ACROSS THE MITT THURSDAY. ALTHOUGH BEST MID LEVEL
SUPPORT ACTUALLY PUSHES EAST EARLY...STILL NICE ENOUGH TRIFECTA OF
WEAKISH RER JET DYNAMICS...FRONTAL INDUCED CONVERGENCE...AND FOLDING
OVER THETA-E RIDGE TO SUPPORT INHERITED SHOWER AND THUNDERSTORM
THREAT. GREATEST POTENTIAL LIKELY SOUTH OF THE BIG BRIDGE...
ESPECIALLY IN THE ALL-TO-OFTEN FAVORED NORTHEAST LOWER WHERE LOW
LEVEL CONVERGENCE WILL BE MAXIMIZED. ML CAPE VALUES HOVERING AROUND
1K J/KG AND CORE OF BULK SHEAR REMAINING POST-FRONTAL AND TO OUR
NORTH SUGGEST STORMS SHOULD BEHAVE THEMSELVES. UNCERTAINTY INCREASES
TO ROUND OUT THE WORK WEEK. WHILE GUIDANCE TRENDS AGREE SURFACE
FRONT WILL PUSH SOUTH OF THE REGION (CONVECTIVE OUTFLOW ENHANCED?)
AS HIGH PRESSURE ROTATES SOUTHEAST ACROSS ONTARIO....SAME CANNOT BE
SAID FOR OFF THE DECK CONVERGENCE AXES AND CORE OF DEEPER MOISTURE.
SOME EVIDENCE THESE WILL RESIDE CLOSE ENOUGH TO KEEP AT LEAST A LOW
END SHOWER/STORM THREAT THURSDAY NIGHT INTO FRIDAY. WILL NOT GO THIS
ROUTE JUST YET (PROBS JUST TOO LOW)...BUT SOMETHING TO KEEP IN MIND
AS WE HEAD TOWARDS THE WEEKEND.
AS FOR THE WEEKEND...POTENTIALLY THE MOST "INTERESTING" PORTION OF
THE FORECAST AS GUIDANCE REMAINS AMAZINGLY STEADFAST PINWHEELING A
STRONG SHORTWAVE TROUGH THROUGH THE NORTHERN LAKES LATER SATURDAY
INTO SUNDAY. RETURN FLOW LOOKS TO BE WELL ESTABLISHED AHEAD OF THIS
FEATURE...WITH PERUSAL OF AVAILABLE MOISTURE PROGS SUGGESTING PWAT
VALUES AOA 1.50 INCHES. DYNAMICS LOOK PRETTY FORMIDABLE...WITH NEAR
NEUTRAL TILT WAVE AND POSSIBLE RER JET DYNAMICS OVERTOPPING A
SEASONABLY STRONG COLD FRONT. STILL SOME MINOR TIMING DIFFERENCES
WITH ALL THE ABOVE...BUT OVERALL A PRETTY WELL AGREED UPON FORECAST.
NO DOUBT A MODEL CONSENSUS WILL SUFFICE...FEATURING POSSIBLE SHOWERS
AND STORMS THROUGH THE WEEKEND...WITH THE GREATEST POTENTIAL
OVERNIGHT SATURDAY INTO EARLY SUNDAY. MUCH TOO EARLY TO GET CAUGHT
UP IN INSTABILITY PROGS AND SPECIFIC MID LEVEL WIND CORES...BUT FROM
A PATTERN RECOGNITION STANDPOINT...THIS SYSTEM LOOKS TO HAVE THE
POTENTIAL TO DRIVE A RATHER VIGOROUS (SEVERE?) SQUALL LINE THROUGH
AT LEAST A PORTION OF THE LAKES REGION. FRONTAL TIMING (CURRENT
TRENDS SUPPORT AN UNFAVORABLE EARLY SUNDAY MORNING FRONTAL PASSAGE)
MIGHT NOT EVEN MATTER MUCH GIVEN SUGGESTED DYNAMICS. DEFINITELY
SOMETHING TO MONITOR IN THE COMING DAYS. DRY WEATHER RETURNS FOR THE
BEGINNING OF NEXT WORK WEEK WITH AN AGGRESSIVE PUSH OF HIGH PRESSURE
BUILDING IN BEHIND THE DEPARTING FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 128 PM EDT WED AUG 1 2012
VFR CONDITIONS ARE PRIMARILY EXPECTED AT ALL TERMINAL SITES
THROUGH THE TAF PERIOD. A COLD FRONT SLOWLY DROPPING THROUGH THE
REGION WILL BRING WITH IT SCATTERED SHOWERS AND THUNDERSTORMS FROM
MID EVENING INTO THE OVERNIGHT HOURS...THOUGH WITH COVERAGE NOT
EXPECTED TO BE HIGH...WILL CONTINUE TO HAVE JUST A VICINITY
MENTION. OF COURSE...ANY HEAVIER RAINS MAY BRIEFLY BRING VISBYS
INTO MVFR OR EVEN IFR RANGE. THE FRONT IS EXPECTED TO WASH OUT
ALONG THE M-55 CORRIDOR...LEAVING LINGERING CHANCES FOR A SHOWER
OR STORM FOR MBL AND PERHAPS TVC RIGHT ON THROUGH 18Z
THURSDAY...WHILE APN/PLN DRY OUT. WITH AN INCREASING JET JUST OFF
THE SURFACE OVERNIGHT...LOW LEVEL WIND SHEAR IS A BIG CONCERN.
OTHERWISE...WINDS ARE EXPECTED TO REMAIN MAINLY 10 KNOTS OR LESS
THROUGH THE PERIOD.
&&
.MARINE...
ISSUED AT 348 AM EDT WED AUG 1 2012
HIGH PRESSURE WILL SLIP SOUTH AND EAST OF THE REGION
TODAY...ALLOWING A SOUTHERLY AND INCREASING WIND FLOW TO
REINTRODUCE A HIGHER MOISTURE CONTENT TO THE GREAT LAKES. A COLD
FRONT ARRIVING LATE TONIGHT WILL WORK ON THIS AIR MASS AND BRING A
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO THE AREA. THE
PRESSURE GRADIENT TIGHTENS UP ENOUGH IN A NEUTRAL STABILITY
SCENARIO FOR A CHANCE AT LOW END SMALL CRAFT ADVISORIES LATER
TONIGHT. WILL NOT INTRODUCE THIS JUST YET...BUT COASTAL CONVERGENT
REGIONS OF NW LOWER MICHIGAN WILL BE THE BEST SHOT AT +25KT GUSTS.
THIS FRONT CONTINUES TO DIVE SOUTH OF US INTO THURSDAY...BEFORE
LIFTING BACK AS A WARM FRONT LATE FRIDAY NIGHT AND INTO THE
WEEKEND. NO OTHER WIND ISSUES ARE FORESEEN THROUGH THE WORK
WEEK...BUT ADVISORIES MAY BE NEEDED FOR THE WEEKEND AHEAD OF NEXT
MORE POTENT COLD FRONT...BOTH AHEAD OF AND BEHIND THIS BOUNDARY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MB
SHORT TERM...SD
LONG TERM...MB
AVIATION...LAWRENCE
MARINE...SD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
309 PM CDT WED AUG 1 2012
.DISCUSSION...
STRONG CONVECTION CONTINUES ACROSS PORTIONS OF NORTHERN WI AT MID
AFTERNOON AHEAD OF A SHORT WAVE OVER NORTHERN MN. MORE CONVECTION
IS EXPECTED LATE THIS AFTERNOON AND EVENING ALONG A COLD FRONT
STRETCHING FROM THE ARROWHEAD OF MN TO CENTRAL SD. THIS CONVECTION
WILL LIKELY HAVE SOME BOUTS OF SEVERE WEATHER WITH LARGE HAIL AND
DAMAGING WINDS. THE WIND THREAT HAS ME MOST CONCERNED WITH DCAPE
VALUES CURRENTLY 1500-1800 J/KG. IN ADDITION... THE RIGHT ENTRANCE
REGION OF A 100+ KNOT JET WILL BE PASSING ACROSS CENTRAL MN EARLY
TONIGHT.
THE FRONT WILL PROGRESS EAST AND SOUTH OF THE FA OVERNIGHT WITH
LINGERING SHOWERS OVER FAR SOUTHERN MN AND WEST CENTRAL WI. THERE
IS SOME CONCERN THAT A SECOND SHORT WAVE OVER WESTERN ND MAY CAUSE
SOME SHOWERS OVER CENTRAL MN DURING THE OVERNIGHT HOURS. A PERIOD
OF DRY WEATHER IS FORECAST FOR MUCH OF THURSDAY AND THURSDAY NIGHT
AS HIGH PRESSURE PASSES ACROSS THE UPPER MISSISSIPPI VALLEY.
A MUCH STRONGER SHORT WAVE AND FRONTAL SYSTEM WILL MOVE ACROSS THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY FROM FRIDAY THROUGH
SATURDAY. VIRTUALLY ALL SOLUTIONS HAVE A CLOSED H5 LOW PASSING
ALONG THE INTERNATIONAL BORDER. THE THREAT FOR SEVERE WEATHER WILL
BE ON THE RISE FRIDAY AFTERNOON IN FAR WESTERN MN AND ACROSS THE
REST OF THE FA FRIDAY NIGHT. AT THIS TIME... CONFIDENCE IS
HIGHEST FOR SEVERE WEATHER FROM WEST CENTRAL MN INTO NORTHERN
AREAS OF THE STATE FRIDAY AFTERNOON AND EVENING WHEN CONSIDERING
SHEAR VALUES... THE LOW LEVEL JET AND THE DIFFERENTIAL TEMPERATURE
ADVECTION SCHEME.
SOME SHOWERS WILL LINGER ON SATURDAY IN THE COLD TROUGH ALOFT
ACROSS THE FA. A PERIOD OF DRY WEATHER IS EXPECTED OR SUNDAY AND
MONDAY ALONG WITH TEMPERATURES MUCH CLOSER TO SEASONAL NORMALS. IN
FACT... I HAVE MSP FORECAST BELOW 80 DEGREES FOR THE HIGH ON
SUNDAY... THIS WOULD BE THE FIRST TIME SINCE JUNE 25TH. A WEAK COLD
FRONT WILL DRIFT SOUTHEAST ACROSS THE REGION MONDAY NIGHT AND
TUESDAY WITH A FEW SHOWERS AND THUNDERSTORMS POSSIBLE... ALTHOUGH
CONFIDENCE IS NOT HIGH ON COVERAGE AT THIS TIME. A COOL NORTHWEST
FLOW WILL END THE FORECAST PERIOD NEXT WEDNESDAY WITH HIGHS AGAIN
FORECAST BELOW THE 80 DEGREE MARK IN MANY AREAS OF THE FA.
&&
.AVIATION... /18Z TAF ISSUANCE/
COMPLEX OF TSRA THAT DEVELOPED IN WC MN EARLIER THIS MORNING AND
MOVED EASTWARD...HAS NEARLY DISSIPATED ACROSS EC MN AND WC WI.
HOWEVER...THE LEFTOVER BOUNDARY HAS CREATED MORE TSRA NEAR
MADISON/MONTEVIDEO AS OF 12 NOON.
AS A SFC LOW DEVELOPS ACROSS CENTRAL SD...AND THE COOL
FRONT/OUTFLOW BOUNDARY HOLDS ON ACROSS SOUTHERN MN...SHRA/TSRA
WILL LIKELY DEVELOP ALONG IT. TIMING REMAINS THE PROBLEM WITH THE
LATEST HRRR INDICATING ARND 21-22Z WHERE TSRA DEVELOP ALONG A LINE
FROM MONTEVIDEO TO THE TWIN CITIES. SINCE TSRA HAVE ALREADY
DEVELOPED IN WC MN...EXPECT THE HRRR HAS A RELATIVELY GOOD HANDLE
ON CONVECTION DEVELOPING THIS AFTN. WILL LIKELY HIGHLIGHT THE BEST
TIME PERIOD OF TSRA AT RWF/MSP/EAU BETWEEN 21-01Z. AFT THIS
ACTIVITY MOVES SOUTH OF MPX TAF SITES...EXPECT MORE DEVELOPMENT
LATER THIS EVENING/OVERNIGHT AS THE MAIN SHRTWV AND A STRONG JET
INTERACTS WITH THE SLOWLY MOVING COOL FRONT IN FAR SOUTHERN MN.
WILL BEGIN TO INTRODUCE VCSH FOR MOST LOCATIONS STARTING AFT
3Z...WITH TRENDS OF THE SHRA MOVING TO THE S/SE OVERNIGHT. THERE
COULD BE PERIODS OF IFR/MVFR CIGS/VSBYS...ESPECIALLY THIS
AFTERNOON IF THE COMPLEX OF TSRA BECOMES MORE WIDESPREAD ACROSS S
MN. WILL CONTINUE WITH VFR CIGS...AND MVFR VSBYS IN TSRA. LATER
SHIFTS CAN UPDATE IF NEEDED. WNDS WILL EVENTUALLY SHFT TO THE N/NE
OVERNIGHT...BUT REMAIN BELOW 10 KTS.
MSP...BELIEVE THE BEST POTENTIAL OF MVFR/IFR CIGS/VSBYS WILL OCCUR
FROM 21-01Z AS A COMPLEX OF TSRA DEVELOPS ACROSS S MN. TIMING AND
HOW WIDESPREAD THIS ACTIVITY BECOMES REMAINS THE CONCERN/QUESTION.
WILL CONTINUE WITH MVFR VSBYS IN TSRA...AND VFR CIGS. WNDS WILL
SLOWLY BECOME W...THEN NW BY THIS EVENING AS THE COOL FRONT SAGS
SOUTHWARD. LATER TONIGHT WINDS WILL BE MORE FROM THE N/NE AND
CONTINUE THRU THE TAF PERIOD.
OUTLOOK...
THURSDAY...VFR. WINDS N AT 5G10KTS.
FRIDAY...VFR DURING THE DAY. EVENING MVFR/IFR CONDITIONS LIKELY IN
SHWRS/TSTMS. WIND SE AT 10G20KTS.
SATURDAY...VFR/MVFR WITH SHWRS/TSTMS POSSIBLE EARLY. WINDS W AT
10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1212 PM CDT WED AUG 1 2012
.DISCUSSION...
OVERVIEW...FEW THINGS TO SORT OUT THIS MORNING. RAISED TEMPS
TODAY...SEEMS WE HAVE UNDERESTIMATED THE WARMING POTENTIAL THE
PAST COUPLE DAYS. CHANCE TO LIKELY POPS THIS AFTERNOON AND EVENING
WITH A SLIGHT RISK OF SEVERE WEATHER FOR WIND AND HAIL...BUT
CAPPING REMAINS A CONCERN. UPPER LOW...THUNDERSTORMS...AND A
COOLING TREND STILL ON TAP LATE IN THE WEEK.
COUPLE FEATURES OF NOTE ON THE MORNING SATELLITE IMAGERY. CONTINUE
TO WATCH AN AREA OF CONVECTION IN SD FALL APART WITH CONTINUED
WARMING CLOUD TOPS. HOWEVER...THINK THE MORE INTERESTING
DEVELOPMENT IS SOME ALTO CU JUST NORTH OF THIS AREA MOVING INTO
EASTERN ND AND WESTERN MN THIS MORNING. THIS IS TIED TO THE STRONG
WARM AIR ADVECTION AND WE ARE OBVIOUSLY GETTING ENOUGH ISENTROPIC
LIFT TO GET US NEAR SATURATION. INCLUDED SMALL POPS ACROSS
NORTHERN FORECAST AREA BETWEEN 15-18Z TO ACCOUNT FOR POSSIBILITY
OF ELEVATED SHOWERS. 00Z NAM AND EC REFLECT THIS IN THE FIRST
12-15 HOURS OF THE FORECAST. PROBABLY THE MORE IMPORTANT QUESTION
IS WHEN AND WHERE SHOWERS/STORMS INITIATE THIS AFTERNOON OR
EVENING. WE PULLED POPS OUT OF THE 12-18Z IN MOST LOCATIONS...AND
STILL SOME SERIOUS QUESTION ABOUT EARLY DEVELOPMENT BETWEEN 18-22Z
WITH THE STRONG WARMING AND CAPPING TODAY. THE 00Z SOUNDING AT MPX
HAD +16C AT 850MB...BUT EXPECT THE 12Z SOUNDING TO LOOK MORE LIKE
THE 00Z ABR SOUNDING WITH +20C TO +23C...ABR WAS ACTUALLY +24.
THINK MORE LIKELY PERIOD FOR STORM INITIATION WILL BE AFTER 22Z
WHEN BOTH NAM/GFS ERODE MOST OF THE CAPPING. WE WILL BE ON THE
SOUTHERN FRINGE OF BEST MID LEVEL FLOW...SO SHEAR WILL BE MARGINAL
FOR ORGANIZATION. HOWEVER...WITH THE EXPECTED WARMING AND MODEST
LOW LEVEL MOISTURE AND STEEP LAPSE RATES...WE WILL HAVE VERY HIGH
CAPE VALUES. SO STRONG UPDRAFTS WITH WIND AND HAIL ARE POSSIBLE
ASSUMING THE CAP DOES INDEED GIVE WAY. THINK IT WILL BY THIS
EVENING. MESO MODEL GUIDANCE FAVORS SOUTHERN MN.
MEANWHILE...WITH 850MB TEMPS THAT WARM AND WHAT SHOULD BE A WELL
MIXED ATMOSPHERE TO GO ALONG WITH PLENTY OF SUN EARLY...THERE
SHOULD BE SOME SERIOUS HEAT TODAY. HAVE TO LIKE THE STRONG W-SW
FLOW TODAY. IN FACT...INCREASED WINDS THIS AFTERNOON. BUMPED HIGHS
TODAY BY 2-4 DEGREES AND HAVE 96 FOR THE TWIN CITIES METRO. THE
NAM IS QUITE AGGRESSIVE AND HAS CLOSE TO OR HIGHER THAN 100 IN MANY
SPOTS. THE GFS IS AS ALWAYS TOO COOL. THE FORECAST HIGHS TODAY ARE
PROBABLY CLOSEST TO THE EC...BUT A DEGREE OR SO HIGHER THAN THE EC
OVERALL. JUST HOPE I DONT WAKE UP AT 1 PM AFTER THIS MID NIGHT
SHIFT AND SEE SITES ALREADY REPORTING MID 90S...WITH HIGHS
EVENTUALLY IN THE UPPER 90S. NOT OUT OF THE QUESTION GIVEN THE
BACKWARD TRAJECTORIES SUGGESTING A FEED OF AIR FROM NEBRASKA WHERE
HIGHS WHERE IN THE MID TO UPPER 90S YESTERDAY.
SYSTEM ON FRIDAY HAS THE POTENTIAL FOR WIDESPREAD THUNDERSTORMS
AND WHAT LOOKS LIKE THE BEST SEVERE THREAT WE HAVE HAD IN A WHILE.
FAVORABLE UPPER FLOW PATTERN WITH THE SUBTROPICAL AND POLAR JETS
COMING TOGETHER AND GOOD THICKNESS DIFFLUENCE OUT AHEAD OF THE
UPPER LOW AND COOLING HEIGHTS SUGGEST LIKELY POPS. THERE WILL ALSO
BE NICE OVERLAP OF SHEAR AND INSTABILITY. GFS HAS 40-55KTS AT
500MB BY 06Z SATURDAY TO GO ALONG WITH 2000-2500 J/KG OF MUCAPE.
THE UPPER LOW LOOKS MORE LIKE SOMETHING TYPICALLY OBSERVED IN
SEPT/OCT...BUT WITH AUGUST WARMTH. A LITTLE WARM AT
850-700MB...BUT 9-11C AT 700MB IS NOT A SHOW STOPPER BY ANY MEANS.
PRIMARY AREA OF FOCUS IS IN CENTRAL MN AND NORTHWEST WI.
&&
.AVIATION.../18Z TAF ISSUANCE/
COMPLEX OF TSRA THAT DEVELOPED IN WC MN EARLIER THIS MORNING AND
MOVED EASTWARD...HAS NEARLY DISSIPATED ACROSS EC MN AND WC WI.
HOWEVER...THE LEFTOVER BOUNDARY HAS CREATED MORE TSRA NEAR
MADISON/MONTEVIDEO AS OF 12 NOON.
AS A SFC LOW DEVELOPS ACROSS CENTRAL SD...AND THE COOL
FRONT/OUTFLOW BOUNDARY HOLDS ON ACROSS SOUTHERN MN...SHRA/TSRA
WILL LIKELY DEVELOP ALONG IT. TIMING REMAINS THE PROBLEM WITH THE
LATEST HRRR INDICATING ARND 21-22Z WHERE TSRA DEVELOP ALONG A LINE
FROM MONTEVIDEO TO THE TWIN CITIES. SINCE TSRA HAVE ALREADY
DEVELOPED IN WC MN...EXPECT THE HRRR HAS A RELATIVELY GOOD HANDLE
ON CONVECTION DEVELOPING THIS AFTN. WILL LIKELY HIGHLIGHT THE BEST
TIME PERIOD OF TSRA AT RWF/MSP/EAU BETWEEN 21-01Z. AFT THIS
ACTIVITY MOVES SOUTH OF MPX TAF SITES...EXPECT MORE DEVELOPMENT
LATER THIS EVENING/OVERNIGHT AS THE MAIN SHRTWV AND A STRONG JET
INTERACTS WITH THE SLOWLY MOVING COOL FRONT IN FAR SOUTHERN MN.
WILL BEGIN TO INTRODUCE VCSH FOR MOST LOCATIONS STARTING AFT
3Z...WITH TRENDS OF THE SHRA MOVING TO THE S/SE OVERNIGHT. THERE
COULD BE PERIODS OF IFR/MVFR CIGS/VSBYS...ESPECIALLY THIS
AFTERNOON IF THE COMPLEX OF TSRA BECOMES MORE WIDESPREAD ACROSS S
MN. WILL CONTINUE WITH VFR CIGS...AND MVFR VSBYS IN TSRA. LATER
SHIFTS CAN UPDATE IF NEEDED. WNDS WILL EVENTUALLY SHFT TO THE N/NE
OVERNIGHT...BUT REMAIN BELOW 10 KTS.
MSP...BELIEVE THE BEST POTENTIAL OF MVFR/IFR CIGS/VSBYS WILL OCCUR
FROM 21-01Z AS A COMPLEX OF TSRA DEVELOPS ACROSS S MN. TIMING AND
HOW WIDESPREAD THIS ACTIVITY BECOMES REMAINS THE CONCERN/QUESTION.
WILL CONTINUE WITH MVFR VSBYS IN TSRA...AND VFR CIGS. WNDS WILL
SLOWLY BECOME W...THEN NW BY THIS EVENING AS THE COOL FRONT SAGS
SOUTHWARD. LATER TONIGHT WINDS WILL BE MORE FROM THE N/NE AND
CONTINUE THRU THE TAF PERIOD.
OUTLOOK...
THURSDAY...VFR. WINDS N AT 5G10KTS.
FRIDAY...VFR DURING THE DAY. EVENING MVFR/IFR CONDITIONS LIKELY IN
SHWRS/TSTMS. WIND SE AT 10G20KTS.
SATURDAY...VFR/MVFR WITH SHWRS/TSTMS POSSIBLE EARLY. WINDS W AT
10G20KTS. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/JLT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
501 PM CDT WED AUG 1 2012
.DISCUSSION...
IT APPEARS THAT A SHORT REPRIEVE FROM THE OPPRESSIVE DRY CONDITIONS
THAT HAVE PLAGUED US AS OF LATE IS ON THE HORIZON AS A COUPLE OF COLD
FRONTS APPROACH THE PLAINS. RADAR LOOP WAS SHOWING PCPN ACTIVITY OVER
WESTERN NEBRASKA AND PARTS OF SOUTH DAKOTA WHILE LATEST OBS WERE
DEPICTING A BNDRY EXTENDING ALONG THE ND/SD BORDER WITH CAA SLOWLY
SPREADING SWD OVER NRN SD. THE BIG QUESTION IS WILL THIS RESULT IN
PCPN OVER THE CWA LATER TONIGHT. IT SEEMS THE MODELS ARE TRYING TO
STALL THE FRONT IN THE VICINITY OF THE NRN CWA...BUT GOOD CHUNK OF
DPVA DOES CROSS THE CWA...AND WITH STOUT 315K UPGLIDE NOT
UNREASONABLE AT THIS POINT TO EXPECT SOME HIGH BASED ACTIVITY
DEVELOPING. LATEST HRRR SEEMS TO HAVE A DECENT HANDLE ON THINGS...
WHICH SUGGEST ACTIVITY COULD GET INTO EASTERN NEBRASKA BEFORE
MIDNIGHT.
CHANCES FOR ANOTHER ROUND PCPN ARE ON TAP HEADING INTO THE
WEEKEND. MODELS ARE IN VERY GOOD AGREEMENT THAT UPSTREAM SHORTWAVE
TROF OVER BRITISH COLUMBIA WILL SLIGHTLY BREAK DOWN THE CONUS
UPPER RIDGE AS IT DROPS INTO THE LOWER 48. THE THERMAL GRADIENT
WITH THE ATTENDANT COLD FRONT WILL BE MORE STOUT IN NATURE. WITH
DECENT ENVIRONMENTAL MOISTURE ON HAND... PRECIP WATER VALUES
AROUND 2"/KI OF 40...IS REASONABLE TO MAINTAIN POPS FRIDAY NIGHT.
POSSIBLE LINGERING ACTIVITY THEN SATURDAY MORNING OVER THE SRN
CWA. RELATIVELY COOLER AFTN HIGHS IN THE MID 80S THEN SUNDAY
AFTERNOON. HEADING INTO NEXT WEEK...THE SITUATION LOOKS RATHER
BLEAK WITH DRY CONDITIONS AND HIGH TEMPS PUSHING BACK TO THE
MID/UPPER 90S AS AN UPPER RIDGE RETURNS OVER THE CONUS.
DEE/BCM
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS ARE EXPECTED TO DOMINATE THE TAF CYCLE. HAVE OPTED
TO REMOVE MENTION OF TSRA AT ALL SITES TONIGHT RATHER THAN
CONVERT THE PROB30 TO TEMPO OR PREVAILING...AS AM NOT CONFIDENT
ABOUT COVERAGE ONCE STORMS DROP OUT OF SD INTO AN AIRMASS THAT IS
VERY DRY BELOW 9-10KFT. THINK STORMS MAY BE SCT TO ISO IN
COVERAGE BY THE TIME THEY REACH KOFK...AND DISSIPATE BEFORE
REACHING KOMA...WITH ANY SCT TO ISO STORMS AT KOFK MOST LIKELY TO
OCCUR AROUND 07-09Z. WILL NEED TO MONITOR POTENTIAL AROUND KLNK
AROUND 08-10Z FOR TSRA POTENTIAL AS THE AIRMASS THERE IS LESS DRY
AND CIGS MAY BE A LITTLE LOWER...WITH PERHAPS MORE OF A CHANCE
THERE THAN THE OTHER SITES. WILL TEMPER TSRA/SHRA MENTION...WITH
LATER SHIFTS ABLE TO ADD TSRA SHOULD A THREAT MATERIALIZE.
OTHERWISE...VFR CONDITIONS ARE EXPECTED...WITH CLOUDS AT OR ABOVE
15KFT OUTSIDE OF ANY SHRA/TSRA. WINDS WILL SHIFT FROM SOUTHERLY TO
MAINLY EASTERLY BEHIND THE WEAK BOUNDARY THAT PASSES THROUGH LATE
TONIGHT.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
$$
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
331 PM PDT WED AUG 1 2012
SYNOPSIS...A DISTURBANCE IN THE ATMOSPHERE COMBINED WITH ABUNDANT
MOISTURE AND INSTABILITY WILL RESULT IN SHOWERS AND THUNDERSTORMS
AROUND AT TIMES THROUGH THIS WEEKEND. ALTHOUGH HEAVY RAIN WILL BE
THE PRIMARY THREAT WITH HEAVIER STORMS...GUSTY WINDS AND HAIL MAY
ALSO OCCUR. BY EARLY NEXT WEEK DRIER AIR LOOKS TO SLOWLY SPREAD EAST
ACROSS THE AREA WHICH SHOULD DECREASE THE CHANCES FOR THUNDERSTORMS
AND ALSO RESULT IN A WARMING TREND.
&&
.SHORT TERM...SO FAR THINGS HAVE NOT BEEN AS ACTIVE THIS AFTERNOON
AS THEY WERE AT THIS POINT YESTERDAY DESPITE AN EXTREMELY MOIST
ATMOSPHERE...PLENTY OF INSTABILITY AND MUCH MORE SUNSHINE. WATER
VAPOR IMAGERY SHOWS THE CENTER OF THE MID/UPPER LEVEL LOW WAS OVER
SOUTHERN CLARK COUNTY AND MOVING SLOWLY NORTHEASTWARD. RADAR SHOWS
AT THE PRESENT MOST OF THE ACTIVITY WAS ABOUT 100 MILES AWAY FROM
THE CENTER OF THE LOW. THE ATMOSPHERE REMAINS EXCEPTIONALLY MOIST
WITH THE 12Z SOUNDING THIS MORNING FROM OUR OFFICE HAVING A PWAT OF
1.82 INCHES. THIS TIED FOR THE SECOND HIGHEST PWAT EVER RECORDED IN
THE SOUNDING CLIMATOLOGY FOR SOUTHERN NEVADA WITH A VALUE BACK IN
AUGUST OF 1984 (THE HIGHEST EVER WAS 1.86 INCHES IN JULY 1966). WITH
SO MUCH MOISTURE PRESENT ANY SHOWER OR THUNDERSTORM THAT GETS GOING
WILL HAVE THE POTENTIAL TO PRODUCE EXTREMELY HEAVY RAIN IN A SHORT
PERIOD OF TIME. THUS THE FLASH FLOOD WATCH OUT WILL REMAIN IN EFFECT.
THE MAIN CHALLENGE FOR THIS EVENING AND THE REST OF TONIGHT WILL BE
JUST HOW ACTIVE THINGS WILL GET. WITH THE MID/UPPER LEVEL LOW
PROGGED TO BE AROUND THROUGH TONIGHT IT WILL BE HARD TO COMPLETELY
SHUT DOWN ALL CONVECTION EXCEPT IN ANY AREAS WHERE THE AIR MASS GETS
WORKED OVER ENOUGH THAT IT BECOMES MUCH MORE STABLE. IF YOU BELIEVE
THE WRF...GFS AND ECMWF CONVECTION SHOULD WIND DOWN AROUND 03Z OR SO
THIS EVENING. ON THE OTHER HAND...THE LOCAL ARW AND NMM MODELS AS
WELL AS THE HRRR MODEL SHOW THE REVERSE WITH THINGS BECOMING MUCH
MORE ACTIVE LATER THIS EVENING. 700 MB STEERING FLOW IS FROM THE
NORTHEAST AND RADAR PRESENTLY SHOWS SHOWERS AND THUNDERSTORMS IN AN
ARCH FROM AROUND ELY TO KANAB. TYPICALLY THIS PATTERN WOULD FAVOR
THIS CONVECTION EVENTUALLY WORKING IN DURING THE LATE EVENING INTO
CLARK COUNTY. IN THE PAST STORMS IN LAS VEGAS ORIGINATING FROM A
NORTHEAST FLOW HAVE USUALLY BEEN RATHER POTENT. THUS...BASED ON A
BLEND OF MODELS WE HAVE KEPT POPS IN THROUGH THE NIGHT FOR MUCH OF
LINCOLN...CLARK...MOHAVE....EASTERN SAN BERNARDINO AND SOUTHERN NYE
COUNTIES. ALTHOUGH FLASH FLOODING REMAINS A THREAT...WE CANNOT RULE
OUT GUSTY WINDS OR HAIL WITH SOME STORMS ESPECIALLY IF THINGS DRY
OUT A LITTLE.
VERY LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED FOR THURSDAY
AND FRIDAY. THE MID/UPPER LEVEL LOW IS FORECAST TO GET TRAPPED NEAR
THE TRIPLE POINT OF CALIFORNIA...NEVADA AND ARIZONA AND EVENTUALLY
WEAKEN TO A MORE ILL-DEFINED VORTICITY FEATURE. MEANWHILE HIGH
PRESSURE IN THE MID AND UPPER LEVELS IS FORECAST TO BECOME CENTERED
OVER CENTRAL NEVADA. THIS HIGH WILL KEEP AN EASTERLY MID-LEVEL FLOW
OVER OUR AREA WHICH BY FRIDAY WILL HELP TO PUSH THE VORTICITY
FEATURE TO THE SOUTHWEST AND BY FRIDAY NIGHT PUSH IT OFFSHORE OF
SOCAL. OVER THE NEXT 2 DAYS THE FARTHER NORTHWEST ONE GOES IN THE
CWFA THE LESS OF CHANCE FOR CONVECTION AS THE HIGH ALOFT WILL KEEP
THE ATMOSPHERE MUCH MORE STABLE. FURTHER SOUTH THE COMBINATION OF
THE VORTICITY FEATURE...INSTABILITY AND SUFFICIENT MOISTURE WILL
KEEP THE POTENTIAL FOR THUNDERSTORMS AROUND. WHILE PWATS ARE
FORECAST TO REMAIN OVER AN INCH OVER THE MOJAVE DESERT WHICH WILL
SUPPORT HEAVY RAIN PRODUCING STORMS...WE WILL NOT ISSUE ANY FLASH
FLOOD WATCHES FOR THURSDAY OR FRIDAY AT THIS TIME DUE TO
UNCERTAINTIES IN JUST HOW ACTIVE IT WILL GET. TEMPS SHOULD BE A FEW
DEGREES ABOVE NORMAL BUT MUCH WARMER THAN WHAT WE HAVE SEEN THE PAST
FEW DAYS OVER THE MOJAVE DESERT. WELL ABOVE NORMAL TEMPS WILL
CONTINUE OVER INYO AND ESMERALDA COUNTY.
.LONG TERM...THE OLD VORTICITY FEATURE OFF OF SOCAL GETS CAUGHT UP
IN A BROAD MID/UPPER LEVEL TROUGH OFF THE WEST COAST ON SATURDAY. IT
APPEARS ENOUGH MOISTURE AND INSTABILITY REMAIN AROUND ON SATURDAY
THAT THE POTENTIAL FOR THUNDERSTORMS WILL CONTINUE ESPECIALLY ACROSS
THE NORTHERN HALF OF THE CWFA WHERE THE BEST INSTABILITY LOOKS TO
SET UP. BY SATURDAY NIGHT INTO SUNDAY DRIER AND MORE STABLE AIR IS
SHOWN TO WORK IN FROM THE SOUTH AS THE OFFSHORE TROUGH EDGES CLOSER
TO THE COAST AND MOST OF THE EMBEDDED ENERGY WITHIN THE TROUGH
STARTS TO LIFT ON NORTH. THUS SUNDAY MAY NOT BE QUITE AS ACTIVE FOR
CONVECTION AND POPS SHOW A SLIGHT TREND DOWN THEN. BY MONDAY INTO
NEXT WEDNESDAY THE TROUGH OFFSHORE STILL EXISTS AND RIDGING ALOFT
SITS OVER THE FOUR CORNERS. THIS WOULD FAVOR A SOUTHWEST FLOW ALOFT
ACROSS OUR AREA WHICH WOULD SPREAD DRIER AND STABLE AIR FURTHER EAST
WITH TIME. I DID LOWER POPS AND DEWPOINTS IN THE WESTERN HALF OF THE
AREA TO ACCOUNT FOR THIS HOWEVER MOIST AND UNSTABLE AIR IS SHOWN TO
LINGER OVER MOHAVE COUNTY AND THIS PART OF THE AREA MAY NEVER REALLY
DRY OUT. TEMPS SHOULD RISE BACK CLOSER TO NORMAL IN MOST AREAS AND
MAY EVEN BE A FEW DEGREES ABOVE NORMAL ON MONDAY AND TUESDAY AS
THINGS REALLY DRY OUT. I LEANED CLOSELY TO THE ECMWF MOS AND BIAS
CORRECTED NUMBERS FOR HIGHS.
&&
.AVIATION...FOR MCCARRAN...LOW CONFIDENCE IN THE TIMING OF ANY
SHRA/TSRA THIS EVENING. THERE IS SOME POSSIBILITY ACTIVITY IN THE
FORM OF AN OUTFLOW BOUNDARY OR SHRA/TSRA ARRIVING FROM THE NORTHEAST
BETWEEN 03Z AND 09Z THIS EVENING. WILL JUST LEAVE IN VCTY ACTIVITY
AND ADJUST THE TAF AS NEEDED. FOR THURSDAY SHRA/TSRA ARE MOST LIKELY
AFTER 19Z. SIMILAR TIMING FOR SHRA/TSRA IN THE APPROACH CORRIDORS.
OTHERWISE WINDS SHOULD FAVOR DIURNAL TRENDS WITH BKN CLOUDS AOA
10K-14K FEET. REDUCED CIGS/VSBY AND GUSTY AND ERRATIC WINDS IN AND
NEAR HEAVIER SHRA/TSRA.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCT SHRA/TSRA THROUGH THIS EVENING WITH ACTIVITY
GENERALLY TRENDING DOWN AFTER 06Z. COVERAGE OF SCT SHRA/TSRA SHOULD
INCREASE AFTER 19Z ON THURSDAY. THE BEST CHANCES FOR SHRA/TSRA WILL
CONTINUE TO BE IN MOHAVE...LINCOLN...CLARK AND THE SAN BERNARDINO
COUNTY DESERTS. GUSTY AND ERRATIC WINDS AND REDUCED CIGS/VSBY NEAR
ANY SHRA/TSRA. OTHERWISE WINDS FAVORING DIURNAL TRENDS WITH BKN CIGS
AOA 10K-14K FEET. DRY AT KBIH WITH A FEW CLOUDS AOA 14K FEET IN THE
AFTERNOON AND EVENING.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH UNTIL 11 PM PDT THIS EVENING FOR NVZ016>022.
AZ...FLASH FLOOD WATCH UNTIL 11 PM MST THIS EVENING FOR AZZ001>003-
036.
CA...FLASH FLOOD WATCH UNTIL 11 PM PDT THIS EVENING FOR CAZ524>527.
&&
$$
STACHELSKI
HTTP://WEATHER.GOV/LASVEGAS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
335 PM CDT WED AUG 1 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT...
MAIN FOCUS OF THE SHORT TERM IS CHANCES OF THUNDERSTORMS TONIGHT IN
THE NORTH...THEN THE CHANCE OF MORE WIDESPREAD THUNDERSTORMS WITH
SEVERE POSSIBILITIES THURSDAY AFTERNOON/NIGHT.
CURRENTLY...SURFACE LOW PRESSURE WAS OVER EASTERN WYOMING WITH A
FRONT/TROUGH EXTENDING EASTWARD ACROSS CENTRAL SOUTH DAKOTA. ONGOING
CONVECTION FROM MID-LEVEL BASED SHOWERS AND THUNDERSTORMS CONTINUED
MOVING EASTWARD ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THIS
ACTIVITY SHOULD BE EAST OF THE FORECAST AREA BY 7 PM.
THE MAIN FOCUS FOR THIS EVENING INVOLVES THE LATEST WATER VAPOR SAT
IMAGERY THAT SHOWS ROTATION DEPICTING AN UPPER LEVEL SHORTWAVE
MOVING EASTWARD ACROSS SOUTHERN SASKATCHEWAN. AN IMPULSE FROM THIS
SHORTWAVE APPEARS TO BE ASSOCIATED WITH A STRONG/SEVERE THUNDERSTORM
THAT DEVELOPED OVER CENTRAL/SOUTHERN SASKATCHEWAN. THIS STORM WAS
MOVING SOUTHEASTWARD TOWARDS THE FAR NORTHEASTERN COUNTIES OF
MONTANA. A FEW OTHER CONVECTIVE CELLS HAVE DEVELOPED AHEAD OF THIS
STORM AS WELL. THE LATEST HRRR MODEL DEPICTS THIS UPPER LEVEL
IMPULSE TO MOVE EAST ALONG THE NORTHERN TIER OF COUNTIES OF NORTH
DAKOTA EARLY THIS EVENING. THUS HAVE ADDED A MENTION OF SLIGHT
CHANCE OF THUNDERSTORMS EARLY THIS EVENING ACROSS NORTHWESTERN AND
NORTH CENTRAL NORTH DAKOTA.
SHOULD BE CLEARING SKIES LATER THIS EVENING WITH OVERNIGHT LOWS FROM
THE UPPER 50S TO LOWER 60S.
ATTENTION THEN TURNS TO THURSDAY...WITH THE APPROACH OF A LARGE
UPPER LEVEL LOW AND SHORTWAVE TROUGH THAT WILL AFFECT WESTERN AND
CENTRAL NORTH DAKOTA THURSDAY AFTERNOON INTO SATURDAY. A SURFACE
TROUGH DEVELOPS IN THE LEE OF THE ROCKIES IN RESPONSE TO THE UPPER
LEVEL LOW/WAVE...WHICH MOVES SOUTH OUT OF ALBERTA THURSDAY AFTERNOON
AND DIVES SOUTHEAST INTO MONTANA BY FRIDAY MORNING. OUT AHEAD OF
THIS ALBERTA CLIPPER SYSTEM...AN UPPER LEVEL IMPULSE MOVES
EASTWARD INTO THE DAKOTAS THURSDAY AFTERNOON...AND MOVES ACROSS THE
STATE THURSDAY NIGHT. IN RESPONSE...THE SURFACE TROUGH IS PROGGED TO
DEVELOP OVER EASTERN MONTANA THURSDAY MORNING AND MOVE INTO WESTERN
NORTH DAKOTA THURSDAY AFTERNOON...MOVING EASTWARD INTO CENTRAL NORTH
DAKOTA THURSDAY NIGHT.
THIS SCENARIO WILL PROVIDE PLENTY OF WIND SHEAR AND LOW LEVEL
MOISTURE AHEAD AND ALONG THE SURFACE TROUGH FOR SOME STRONG TO
SEVERE THUNDERSTORMS TO DEVELOP. KEPT THURSDAY MORNING DRY IN THE
FORECAST...WITH A CHANCE OF THUNDERSTORMS THURSDAY AFTERNOON OVER
MAINLY WESTERN NORTH DAKOTA IN THE VICINITY OF THE SURFACE TROUGH.
THURSDAY NIGHT CHANCES INCREASE AND HAVE KEPT THE 60 PERCENT
"LIKELY" CATEGORY FOR THE EASTERN PART OF CENTRAL NORTH DAKOTA LATE
THURSDAY NIGHT.
STORM PREDICTION CENTER DOES HAVE OUR AREA IN A SLIGHT RISK FOR
SEVERE THUNDERSTORMS THURSDAY AFTERNOON/NIGHT FOR THE WESTERN
DAKOTAS...AND FOR THE EASTERN DAKOTAS ON FRIDAY. STRONG HEATING
AHEAD OF THE MAIN SYSTEM WILL ALLOW TEMPERATURES TO RISE INTO THE
UPPER 80S/LOWER 90S THURSDAY...WITH LOWS THURSDAY NIGHT 60 TO 65.
STRONG COLD FRONT BEHIND THE SYSTEM FOR A COOLER WEEKEND.
.LONG TERM...FRIDAY THROUGH NEXT WEDNESDAY...
THE EXTENDED PERIOD BEGINS WITH A SFC TROUGH OVER THE DAKOTAS AND A
STRONG UPPER LEVEL LOW APPROACHING THE NORTHERN PLAINS. WILL LIKELY
SEE ONGOING PRECIPITATION FROM THURSDAY NIGHT AT THE VERY START OF
THE PERIOD. CHANCES FOR SHOWERS ARE LIKELY OVER CENTRAL AND EASTERN
NORTH DAKOTA...WITH A GOOD CHANCE ACROSS THE WEST FRIDAY DAYTIME. I
DID SCALE BACK ON THUNDER WORDING FROM WEST TO CENTRAL FRIDAY
MORNING INTO FRIDAY AFTERNOON AS WE STABILIZE ONCE THE UPPER LOW
ADVECTS INTO WESTERN ND. MODELS SHOWING AN ENHANCED POSSIBILITY OF
STRONG TO SEVERE WEATHER EAST OF HIGHWAY 83 FRIDAY DAYTIME. WILL
MENTION IN THE HWO. WRAP AROUND PRECIPITATION...ESPECIALLY ACROSS
THE NORTH...FRIDAY NIGHT INTO SATURDAY WITH THE LOW PROPAGATING EAST
ALONG THE INTERNATIONAL BORDER. MAINTAINED A SLIGHT CHANCE OF
THUNDER FRIDAY NIGHT...AND WENT ALL SHOWERS SATURDAY DAYTIME WITH
LITTLE IF ANY CAPE. TEMPERATURES WILL BE NOTICEABLY COOLER FRIDAY
AND SATURDAY DUE TO THE CLOUDS...PRECIP...AND STRONG CAA ASSOCIATED
WITH THE LOW. HIGHS FRIDAY WILL CLIMB INTO THE 80S AHEAD OF THE SFC
TROUGH OVER MY SOUTHEAST...BUT SHOULD REMAIN IN THE 70S ELSEWHERE.
HIGHS SATURDAY WILL CONTINUE TO BE WELL BELOW AVERAGE...FROM AROUND
70 EAST TO NEAR 75 WEST.
HIGH PRESSURE WILL KEEP THINGS DRY SATURDAY NIGHT THROUGH SUNDAY
NIGHT ALONG WITH A WARMING TREND BEGINNING. HIGHS SUNDAY SHOULD BE
ABOUT 10-15 DEGREES WARMER THAN SATURDAY.
NORTHWESTERLY FLOW ALOFT IS DEPICTED MON-WED. THIS WILL HELP KEEP
THE REAL WARM AIR WEST AND SOUTH OF THE STATE MONDAY AND TUESDAY
RESULTING IN NEAR NORMAL HIGHS AND LOWS. WILL ALSO MAINTAIN A DRY
FORECAST FOR NOW MONDAY-WEDNESDAY. WHILE IT IS POSSIBLE A WEAK
EMBEDDED WAVE COULD DEVELOP ISOLD-SCT SHOWERS/THUNDER...TOO
UNCERTAIN RIGHT NOW TO INTRODUCE WEATHER INTO THE FORECAST.
&&
.AVIATION...
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE 18Z TAF ISSUANCE
PERIOD. A MID LEVEL DISTURBANCE CONTINUES TO BRING EXTENSIVE CLOUD
COVER TO WEST AND CENTRAL NORTH DAKOTA ALONG WITH SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS. CLOUD BASES REMAIN RELATIVELY HIGH AT
AROUND 10K FT AGL...OCCASIONALLY DROPPING TO NEAR 4K FT AGL IN
SHRA/TSRA. WILL CONTINUE THE MENTION OF VCTS/VCSH DUE TO THE ISOLD
NATURE OF THE PRECIPITATION. WILL ISSUE TEMPO GROUPS AS NEEDED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JV
LONG TERM/AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
318 PM CDT WED AUG 1 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
PRIMARY FORECAST CHALLENGE IS SHORT-TERM PRECIPITATION CHANCES...
FOLLOWED BY FRIDAY/S SYSTEM. GFS/NAM/ECMWF/GEM ARE IN REASONABLE
AGREEMENT...BUT HAVE HANDLED TODAY/S SHOWERS AND STORMS POORLY.
LATEST HRRR BEST REFLECTS CURRENT SITUATION AND WILL FOLLOW ITS
SOLUTION FOR THE NEXT 6-12 HOURS.
20 UTC RADAR LOOP SHOWS TWO AREAS OF PRECIPITATION. THE FIRST IS
A LINE OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS FROM GLENDIVE
MT TO NEAR DEVILS LAKE...MOVING EAST AROUND 35 KTS. THE SECOND IS
A LINE OF SHOWERS AND THUNDERSTORMS FROM WALL SD TO ORTONVILLE
MN...ALSO MOVING TO THE EAST AROUND 35 KTS. BOTH BANDS ARE
ASSOCIATED WITH AN UPPER LEVEL SHORT-WAVE CROSSING INTO WESTERN
ND...BUT WEAK INSTABILITY ACROSS MUCH OF ND IS LIMITING
THUNDERSTORM ACTIVITY. MAJORITY OF THUNDERSTORMS SHOULD REMAIN
SOUTH OF THE ND/SD STATE LINE ALONG 2000 TO 3000 J/KG MLCAPE
INSTABILITY AXIS.
LATEST HRRR BRINGS SHOWERS AND ISOLATED THUNDERSTORMS ACROSS
CENTRAL ND MAINLY INTO THE CENTRAL/NORTHERN VALLEY AND THEN PORTIONS
OF NORTHWEST MN LATE THIS AFTERNOON AND EVENING. EXPANDED 20 POPS
INTO THESE AREAS THROUGH 03 UTC. WITH NO OTHER MODEL ACCURATELY
REFLECTING THIS SCENARIO...UNCERTAIN HOW LONG SHOWERS WILL HOLD
TOGETHER AND WILL KEEP FORECAST DRY ACROSS THE NORTH AFTER 03 UTC.
DID ADD AN AREA OF 20 POPS ACROSS THE FAR SOUTH AS WELL THROUGH 06
UTC TO CATCH ANY STRAY ACTIVITY FROM SD CROSSING THE BORDER THIS
EVENING. NO SEVERE WEATHER IS EXPECTED AT THIS TIME.
SURFACE HIGH PRESSURE BUILDS ACROSS THE CWA BY 12 UTC THURSDAY...
SO SHOULD SEE DECREASING CLOUDS AND LIGHT WIND ALLOWING MORNING
LOWS TO DROP INTO THE UPPER 50S TO LOWER 60S. THE REST OF THE DAY
WILL BE DRY WITH A MIX OF SUN AND CLOUDS AND TEMPERATURES SIMILAR
TO TODAY.
ATTENTION THEN TURNS TO THURSDAY NIGHT THROUGH SATURDAY AS A
STRONG CANADIAN CLOSED LOW MOVES ACROSS THE NORTHERN PLAINS.
PRIMARY CHANGE TO PREVIOUS FORECAST WAS TO SLOW EASTWARD
PROGRESSION OF POPS. GFS/ECMWF IN GOOD AGREEMENT...SUGGESTING BEST
FORCING WILL BE ALONG MID-LEVEL TROUGH WITH ADDITIONAL SUPPORT
FROM A 50 TO 80 KT 300 HPA JET ROUNDING THE BASE OF THE UPPER LOW.
SPREAD 60 TO 70 POPS FROM WEST TO EAST THURSDAY NIGHT THROUGH
EARLY SATURDAY MORNING WITH THE BEST CHANCE FOR ACCUMULATING
RAINFALL ALONG THE VALLEY FRIDAY AFTERNOON. STILL TO EARLY TO
PINPOINT MOST FAVORED AREA FOR SEVERE CONVECTION...BUT LATEST
GFS/ECMWF DO DEVELOP SOME KIND OF MCS ACROSS SOUTHEAST ND FRIDAY
AFTERNOON. SPC DAY 3 CONVECTIVE OUTLOOK PAINTS A SLIGHT RISK
ACROSS THE ENTIRE CWA EXCEPT THE FAR WESTERN DEVILS LAKE BASIN.
SOMETHING TO WATCH CLOSELY OVER THE NEXT SEVERAL MODEL RUNS.
COLD FRONT WILL MOVE WELL EAST OF THE AREA FOR SATURDAY...USHERING
IN A CHANGE OF AIR MASS. HIGHS SATURDAY ONLY EXPECTED TO REACH THE
UPPER 60S TO LOWER 70S WITH PERIODS OF SCATTERED WRAP AROUND RAIN
SHOWERS. WINDS WILL ALSO BE BREEZY FROM THE NORTHWEST WITH
OCCASIONAL GUSTS TO 30 MPH.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LONG RANGE MODELS AGREEABLE THROUGH MONDAY...THEN DIVERGE.
NORTHWEST FLOW ALOFT APPEARS LIKELY THROUGH THE PERIOD AS UPPER
RIDGE TO THE WEST GRADUALLY PROPAGATES TO THE EAST. MODELS
INDICATE A CANADIAN UPPER LOW SENDING A COLD FRONT THROUGH THE
REGION ON MONDAY...BUT DRY AIRMASS SHOULD LIMIT PRECIP. MONDAY HAS
THE POTENTIAL TO BE THE WARMEST DAY...DEPENDING ON THE FROPA
TIMING. THE ECMWF IS WEAKER WITH THE UPPER RIDGE AND DOES ALLOW
FOR SOME WAVES TO ROUND THIS FEATURE BY LATER IN THE PERIOD. WILL
CONTINUE WITH DRY FORECAST WITH SFC RIDGING AND DRY AIRMASS
EXPECTED.
&&
.AVIATION...
VFR CIGS THROUGH THE PERIOD. ISOLATED SHOWERS POSSIBLE INTO THE
EVENING...BUT WILL BE VERY LIGHT. WINDS WILL BECOME LIGHT THIS
EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
ROGERS/TG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
430 PM EDT WED AUG 1 2012
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION
TONIGHT...THEN WEAK HIGH PRESSURE WILL BUILD OVER THE AREA THURSDAY
THROUGH SATURDAY. THE HIGH PRESSURE WILL START TO BREAK DOWN FROM
THE NORTHWEST ON SUNDAY...WITH A SURFACE COLD FRONT APPROACHING THE
REGION MONDAY...AND LINGERING IN THE VICINITY THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
2030 UTC UPDATE...SKY COVER WAS UPDATED FROM THE VISIBLE SATELLITE
IMAGERY. POPS WERE ADJUSTED PER RADAR TRENDS...ACCOUNTING FOR
ONGOING ISOLATED CONVECTION...AND THE MOVEMENT OF MORE WIDESPREAD
CELLS IN EAST TN APPROACHING THE SW NC MOUNTAINS.
AS OF 220 PM EDT...THE RAP CURRENTLY SHOWS A WEAK H5 SHORT WAVE OVER
THE NC MTNS. A STRONGER WAVE IS UPSTREAM OF THE REGION OVER NRN
KY. AN ENHANCED CU FIELD IS BEGINNING TO DEVELOP OVER NRN TN...SE KY
AND SW VA AHEAD OF THIS SHORT WAVE. THE 0-6KM EFFECTIVE SHEAR IS ON
THE ORDER OF 30 KTS WITH THIS FEATURE...AND I/D EXPECT THAT
CONVECTION WILL MAKE IT INTO THE MTNS BY EARLY EVENING. MORE
ISOLATED CONVECTION MAY ALSO DEVELOP OVER THE NEXT COUPLE HOURS
ACROSS THE HIGH TERRAIN...BUT THE MORE ORGANIZED CONVECTIVE ACTIVITY
SHOULD BEGIN TO AFFECT THE WRN CAROLINAS AROUND 6 PM. CONFIDENCE IN
AN ORGANIZED MCS AFFECTING A LARGE AREA ISN/T THAT HIGH...THOUGH
IT/S NOT OUT OF THE QUESTION. HOWEVER...BEEFIER HIGH CHANCE POPS
SEEM REASONABLE OVER THE MOUNTAINS...AND STORMS COULD LAST A WAYS
INTO THE OVERNIGHT PERIOD OVER THE FOOTHILLS AND PIEDMONT AS WELL. A
FEW OF THE STORMS WILL PRODUCE DAMAGING WINDS AS THE DCAPE VALUES
RANGE FROM 1000-1200 ACROSS THE REGION. THIS WILL BE ADDED TO THE
HWO.
H5 HEIGHTS RISE A LITTLE TOMORROW AS THE SRN PLAINS RIDGE WILL
BRIEFLY PUSH TO THE EAST. HOWEVER...A WEAK SFC FRONT WILL SET UP
OVER THE FOOTHILLS. THE NAM GENERATES GOOD CONVERGENCE OVER THE
FOOTHILLS AND PIEDMONT IN THE AFTN. THE MASS AND MOISTURE
CONVERGENCE RESULTS IS CONSIDERABLE CONVECTIVE COVERAGE ON THAT
MODEL EAST OF THE MTNS LATE IN THE DAY. EVEN THE SREF IS SHOWING
SOME FAIRLY HIGH 3-HLY POPS. THEREFORE I/VE RAISED POPS INTO THE LOW
CHANCE RANGE OVER PARTS OF THE I-85 URBAN CORRIDOR FOR TMRW. IT WILL
ALSO BE A HOT DAY WITH MANY FOOTHILL AND PIEDMONT LOCATIONS WARMING
INTO THE MID 90S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
AS OF 230 PM EDT WED...THE OVERALL PATTERN THROUGH THE SHORT RANGE
CONTINUES TO SHOW A WEAKNESS ALONG THE EAST COAST BETWEEN TWO RIDGES
TO OUR EAST AND WEST. EXPECT ISOLATED CONVECTION TO DIMINISH
THURSDAY EVENING WITH THE LOSS OF HEATING. FRIDAY LOOKS MORE
FAVORABLE FOR A LARGER NUMBER OF STORMS. THE MODELS SHOW SOME SORT
OF SHORT WAVE MOVING ACROSS THE TN VALLEY AND CUMBERLAND PLATEAU IN
THE AFTERNOON...WHICH SHOULD HELP TO ORGANIZE STORMS OVER THE MTNS.
ONCE FORMED...THE STORMS SHOULD SPREAD OUT ACROSS THE FOOTHILLS AND
PIEDMONT LATE IN THE DAY IN THE USUAL MANNER. TEMPS WERE NUDGED
TOWARD A GUIDANCE BLEND...WHICH WAS A FEW DEGREES COOLER THAN THE
PREVIOUS FCST. THE WAVE DAMPENS OUT ON SATURDAY BUT MOISTURE IS
DEEPER WITH A MORE SW FLOW AT LOW LEVELS. WE SHOULD SEE AN INCREASE
IN UPPER DIVERGENCE LATE IN THE DAY. THIS SHOULD LEAD TO COVERAGE A
BIT BETTER YET THAN FRIDAY...SO POP WAS RAISED WELL INTO THE CHANCE
RANGE. TEMPS WERE KEPT NEAR THE OLD FCST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM EDT WED...THE LATEST MEDIUM RANGE MODELS CONTINUE TO
INDICATE THAT A DEEP MOIST SW FLOW REMAINS IN PLACE OVER THE REGION
THROUGH THE WEEKEND AS WEAK RIDGE OF HIGH PRESSURE PERSISTS OVER THE
SOUTHEASTERN STATES. THE HEIGHTS WILL GRADUALLY FALL SUN INTO MON AS
A STRONG NORTHERN STREAM UPPER LOW PRESSURE MOVES THROUGH THE GREAT
LAKES REGION. A COLD FRONT WILL APPROACH FROM THE NW ON LATE SUNDAY
AND LIKELY STALL IN OR JUST NORTH OF THE AREA THROUGH WEDNESDAY.
HAVE MENTIONED HEALTHY DIURNAL SCATTERED POPS EACH AFTN/EVENING AS
MODEL SOUNDINGS SHOW HIGH PW VALUES (OVER 2 INCHES) AND MODERATE
INSTABILITY ACROSS OUR CWA. TEMPERATURES WILL REMAIN NEAR...OR A
COUPLE DEGREES BELOW SEASONAL AVERAGES THROUGH THE PERIOD.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...SCT CU SHOULD RISE TO AROUND 5 KFT LATER IN THE AFTN. A
WEAK UPPER LOW MAY BRING SOME SHRA/TSTMS TO THE VICINITY IN SEVERAL
HOURS TIME...PROBABLY INTO THE EVENING HOURS. CONFIDENCE ISN/T HIGH
ENOUGH TO ADD A TEMPO GROUP YET...BUT VCSH HAS BEEN ADDED STARTING
IN THE EARLY EVENING. NOT EXPECTING ANY CIG OR VSBY PROBLEMS
OVERNIGHT UNLESS A SHRA HAPPENS TO AFFECT THE AIRFIELD. THE WINDS
SHOULD REMAIN LIGHT OUT OF THE W TO NW THIS AFTN...THOUGH THEY WILL
BE VARIABLE. A MORE S TO SW COMPONENT TO THE FLOW IS EXPECTED
TONIGHT AND THU MORNING.
ELSEWHERE...A WEAK UPPER LOW WILL CROSS THE REGION THIS EVENING.
THIS MAY GIVE RISE TO SCT SHRA/TSTM ACTIVITY STARTING IN THE LATE
AFTN OR EARLY EVENING ACROSS THE FOOTHILLS AND PIEDMONT. STORMS WILL
GO A LITTLE EARLIER AT KAVL. HOWEVER...CONFIDENCE ISN/T HIGH ENOUGH
TO ADD TEMPO/S ANYWHERE YET. WINDS WILL BE LIGHT NW OVER THE NC
ZONES AND OUT OF THE W TO WSW OVER THE UPSTATE. WINDS ACROSS THE
REGION WILL TURN A LITTLE MORE SOUTHERLY TONIGHT. WITH A DAY OF
DRYING UNDER OUR BELTS...LOW CLOUDS AND FOG SHOULD BE FAR LESS
WIDESPREAD TONIGHT. HOWEVER...THE FRENCH BROAD VALLEY SHOULD SEE A
GOOD AMOUNT OF FOG AND LIFR CONDITIONS HAVE BEEN ADDED TO KAVL A
LITTLE LATER THAN THEY DEVELOPED LAST NIGHT.
OUTLOOK...SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL
SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...JAT/MCAVOY
SHORT TERM...PM
LONG TERM...JOH
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
339 PM EDT WED AUG 1 2012
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION
TONIGHT...THEN WEAK HIGH PRESSURE WILL BUILD OVER THE AREA THURSDAY
THROUGH SATURDAY. THE HIGH PRESSURE WILL START TO BREAK DOWN FROM
THE NORTHWEST ON SUNDAY...WITH A SURFACE COLD FRONT APPROACHING THE
REGION MONDAY...AND LINGERING IN THE VICINITY THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
1935 UTC UPDATE...SKY COVER WAS UPDATED FROM THE LATEST VISIBLE
SATELLITE IMAGERY...AND POPS ADJUSTED ACCORDINGLY. POPS WERE REDUCED
FOR THE NEXT FEW HOURS ACROSS MUCH OF THE AREA...ESPECIALLY EAST OF
THE MOUNTAINS...BUT WERE RAISED IN A FEW AREAS WHERE SHOWERS WERE
ALREADY FORMING.
AS OF 220 PM EDT...THE RAP CURRENTLY SHOWS A WEAK H5 SHORT WAVE OVER
THE NC MTNS. A STRONGER WAVE IS UPSTREAM OF THE REGION OVER NRN
KY. AN ENHANCED CU FIELD IS BEGINNING TO DEVELOP OVER NRN TN...SE KY
AND SW VA AHEAD OF THIS SHORT WAVE. THE 0-6KM EFFECTIVE SHEAR IS ON
THE ORDER OF 30 KTS WITH THIS FEATURE...AND I/D EXPECT THAT
CONVECTION WILL MAKE IT INTO THE MTNS BY EARLY EVENING. MORE
ISOLATED CONVECTION MAY ALSO DEVELOP OVER THE NEXT COUPLE HOURS
ACROSS THE HIGH TERRAIN...BUT THE MORE ORGANIZED CONVECTIVE ACTIVITY
SHOULD BEGIN TO AFFECT THE WRN CAROLINAS AROUND 6 PM. CONFIDENCE IN
AN ORGANIZED MCS AFFECTING A LARGE AREA ISN/T THAT HIGH...THOUGH
IT/S NOT OUT OF THE QUESTION. HOWEVER...BEEFIER HIGH CHANCE POPS
SEEM REASONABLE OVER THE MOUNTAINS...AND STORMS COULD LAST A WAYS
INTO THE OVERNIGHT PERIOD OVER THE FOOTHILLS AND PIEDMONT AS WELL. A
FEW OF THE STORMS WILL PRODUCE DAMAGING WINDS AS THE DCAPE VALUES
RANGE FROM 1000-1200 ACROSS THE REGION. THIS WILL BE ADDED TO THE
HWO.
H5 HEIGHTS RISE A LITTLE TOMORROW AS THE SRN PLAINS RIDGE WILL
BRIEFLY PUSH TO THE EAST. HOWEVER...A WEAK SFC FRONT WILL SET UP
OVER THE FOOTHILLS. THE NAM GENERATES GOOD CONVERGENCE OVER THE
FOOTHILLS AND PIEDMONT IN THE AFTN. THE MASS AND MOISTURE
CONVERGENCE RESULTS IS CONSIDERABLE CONVECTIVE COVERAGE ON THAT
MODEL EAST OF THE MTNS LATE IN THE DAY. EVEN THE SREF IS SHOWING
SOME FAIRLY HIGH 3-HLY POPS. THEREFORE I/VE RAISED POPS INTO THE LOW
CHANCE RANGE OVER PARTS OF THE I-85 URBAN CORRIDOR FOR TMRW. IT WILL
ALSO BE A HOT DAY WITH MANY FOOTHILL AND PIEDMONT LOCATIONS WARMING
INTO THE MID 90S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
AS OF 230 PM EDT WED...THE OVERALL PATTERN THROUGH THE SHORT RANGE
CONTINUES TO SHOW A WEAKNESS ALONG THE EAST COAST BETWEEN TWO RIDGES
TO OUR EAST AND WEST. EXPECT ISOLATED CONVECTION TO DIMINISH
THURSDAY EVENING WITH THE LOSS OF HEATING. FRIDAY LOOKS MORE
FAVORABLE FOR A LARGER NUMBER OF STORMS. THE MODELS SHOW SOME SORT
OF SHORT WAVE MOVING ACROSS THE TN VALLEY AND CUMBERLAND PLATEAU IN
THE AFTERNOON...WHICH SHOULD HELP TO ORGANIZE STORMS OVER THE MTNS.
ONCE FORMED...THE STORMS SHOULD SPREAD OUT ACROSS THE FOOTHILLS AND
PIEDMONT LATE IN THE DAY IN THE USUAL MANNER. TEMPS WERE NUDGED
TOWARD A GUIDANCE BLEND...WHICH WAS A FEW DEGREES COOLER THAN THE
PREVIOUS FCST. THE WAVE DAMPENS OUT ON SATURDAY BUT MOISTURE IS
DEEPER WITH A MORE SW FLOW AT LOW LEVELS. WE SHOULD SEE AN INCREASE
IN UPPER DIVERGENCE LATE IN THE DAY. THIS SHOULD LEAD TO COVERAGE A
BIT BETTER YET THAN FRIDAY...SO POP WAS RAISED WELL INTO THE CHANCE
RANGE. TEMPS WERE KEPT NEAR THE OLD FCST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM EDT WED...THE LATEST MEDIUM RANGE MODELS CONTINUE TO
INDICATE THAT A DEEP MOIST SW FLOW REMAINS IN PLACE OVER THE REGION
THROUGH THE WEEKEND AS WEAK RIDGE OF HIGH PRESSURE PERSISTS OVER THE
SOUTHEASTERN STATES. THE HEIGHTS WILL GRADUALLY FALL SUN INTO MON AS
A STRONG NORTHERN STREAM UPPER LOW PRESSURE MOVES THROUGH THE GREAT
LAKES REGION. A COLD FRONT WILL APPROACH FROM THE NW ON LATE SUNDAY
AND LIKELY STALL IN OR JUST NORTH OF THE AREA THROUGH WEDNESDAY.
HAVE MENTIONED HEALTHY DIURNAL SCATTERED POPS EACH AFTN/EVENING AS
MODEL SOUNDINGS SHOW HIGH PW VALUES (OVER 2 INCHES) AND MODERATE
INSTABILITY ACROSS OUR CWA. TEMPERATURES WILL REMAIN NEAR...OR A
COUPLE DEGREES BELOW SEASONAL AVERAGES THROUGH THE PERIOD.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...SCT CU SHOULD RISE TO AROUND 5 KFT LATER IN THE AFTN. A
WEAK UPPER LOW MAY BRING SOME SHRA/TSTMS TO THE VICINITY IN SEVERAL
HOURS TIME...PROBABLY INTO THE EVENING HOURS. CONFIDENCE ISN/T HIGH
ENOUGH TO ADD A TEMPO GROUP YET...BUT VCSH HAS BEEN ADDED STARTING
IN THE EARLY EVENING. NOT EXPECTING ANY CIG OR VSBY PROBLEMS
OVERNIGHT UNLESS A SHRA HAPPENS TO AFFECT THE AIRFIELD. THE WINDS
SHOULD REMAIN LIGHT OUT OF THE W TO NW THIS AFTN...THOUGH THEY WILL
BE VARIABLE. A MORE S TO SW COMPONENT TO THE FLOW IS EXPECTED
TONIGHT AND THU MORNING.
ELSEWHERE...A WEAK UPPER LOW WILL CROSS THE REGION THIS EVENING.
THIS MAY GIVE RISE TO SCT SHRA/TSTM ACTIVITY STARTING IN THE LATE
AFTN OR EARLY EVENING ACROSS THE FOOTHILLS AND PIEDMONT. STORMS WILL
GO A LITTLE EARLIER AT KAVL. HOWEVER...CONFIDENCE ISN/T HIGH ENOUGH
TO ADD TEMPO/S ANYWHERE YET. WINDS WILL BE LIGHT NW OVER THE NC
ZONES AND OUT OF THE W TO WSW OVER THE UPSTATE. WINDS ACROSS THE
REGION WILL TURN A LITTLE MORE SOUTHERLY TONIGHT. WITH A DAY OF
DRYING UNDER OUR BELTS...LOW CLOUDS AND FOG SHOULD BE FAR LESS
WIDESPREAD TONIGHT. HOWEVER...THE FRENCH BROAD VALLEY SHOULD SEE A
GOOD AMOUNT OF FOG AND LIFR CONDITIONS HAVE BEEN ADDED TO KAVL A
LITTLE LATER THAN THEY DEVELOPED LAST NIGHT.
OUTLOOK...SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL
SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...JAT/MCAVOY
SHORT TERM...PM
LONG TERM...JOH
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
250 PM EDT WED AUG 1 2012
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION
TONIGHT...THEN WEAK HIGH PRESSURE WILL BUILD OVER THE AREA THURSDAY
THROUGH SATURDAY. THE HIGH PRESSURE WILL START TO BREAK DOWN FROM
THE NORTHWEST ON SUNDAY...WITH A SURFACE COLD FRONT APPROACHING THE
REGION MONDAY...AND LINGERING IN THE VICINITY THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 220 PM EDT...THE RAP CURRENTLY SHOWS A WEAK H5 SHORT WAVE OVER
THE NC MTNS. A STRONGER WAVE IS UPSTREAM OF THE REGION OVER NRN
KY. AN ENHANCED CU FIELD IS BEGINNING TO DEVELOP OVER NRN TN...SE KY
AND SW VA AHEAD OF THIS SHORT WAVE. THE 0-6KM EFFECTIVE SHEAR IS ON
THE ORDER OF 30 KTS WITH THIS FEATURE...AND I/D EXPECT THAT
CONVECTION WILL MAKE IT INTO THE MTNS BY EARLY EVENING. MORE
ISOLATED CONVECTION MAY ALSO DEVELOP OVER THE NEXT COUPLE HOURS
ACROSS THE HIGH TERRAIN...BUT THE MORE ORGANIZED CONVECTIVE ACTIVITY
SHOULD BEGIN TO AFFECT THE WRN CAROLINAS AROUND 6 PM. CONFIDENCE IN
AN ORGANIZED MCS AFFECTING A LARGE AREA ISN/T THAT HIGH...THOUGH
IT/S NOT OUT OF THE QUESTION. HOWEVER...BEEFIER HIGH CHANCE POPS
SEEM REASONABLE OVER THE MOUNTAINS...AND STORMS COULD LAST A WAYS
INTO THE OVERNIGHT PERIOD OVER THE FOOTHILLS AND PIEDMONT AS WELL. A
FEW OF THE STORMS WILL PRODUCE DAMAGING WINDS AS THE DCAPE VALUES
RANGE FROM 1000-1200 ACROSS THE REGION. THIS WILL BE ADDED TO THE
HWO.
H5 HEIGHTS RISE A LITTLE TOMORROW AS THE SRN PLAINS RIDGE WILL
BRIEFLY PUSH TO THE EAST. HOWEVER...A WEAK SFC FRONT WILL SET UP
OVER THE FOOTHILLS. THE NAM GENERATES GOOD CONVERGENCE OVER THE
FOOTHILLS AND PIEDMONT IN THE AFTN. THE MASS AND MOISTURE
CONVERGENCE RESULTS IS CONSIDERABLE CONVECTIVE COVERAGE ON THAT
MODEL EAST OF THE MTNS LATE IN THE DAY. EVEN THE SREF IS SHOWING
SOME FAIRLY HIGH 3-HLY POPS. THEREFORE I/VE RAISED POPS INTO THE LOW
CHANCE RANGE OVER PARTS OF THE I-85 URBAN CORRIDOR FOR TMRW. IT WILL
ALSO BE A HOT DAY WITH MANY FOOTHILL AND PIEDMONT LOCATIONS WARMING
INTO THE MID 90S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
AS OF 230 PM EDT WED...THE OVERALL PATTERN THROUGH THE SHORT RANGE
CONTINUES TO SHOW A WEAKNESS ALONG THE EAST COAST BETWEEN TWO RIDGES
TO OUR EAST AND WEST. EXPECT ISOLATED CONVECTION TO DIMINISH
THURSDAY EVENING WITH THE LOSS OF HEATING. FRIDAY LOOKS MORE
FAVORABLE FOR A LARGER NUMBER OF STORMS. THE MODELS SHOW SOME SORT
OF SHORT WAVE MOVING ACROSS THE TN VALLEY AND CUMBERLAND PLATEAU IN
THE AFTERNOON...WHICH SHOULD HELP TO ORGANIZE STORMS OVER THE MTNS.
ONCE FORMED...THE STORMS SHOULD SPREAD OUT ACROSS THE FOOTHILLS AND
PIEDMONT LATE IN THE DAY IN THE USUAL MANNER. TEMPS WERE NUDGED
TOWARD A GUIDANCE BLEND...WHICH WAS A FEW DEGREES COOLER THAN THE
PREVIOUS FCST. THE WAVE DAMPENS OUT ON SATURDAY BUT MOISTURE IS
DEEPER WITH A MORE SW FLOW AT LOW LEVELS. WE SHOULD SEE AN INCREASE
IN UPPER DIVERGENCE LATE IN THE DAY. THIS SHOULD LEAD TO COVERAGE A
BIT BETTER YET THAN FRIDAY...SO POP WAS RAISED WELL INTO THE CHANCE
RANGE. TEMPS WERE KEPT NEAR THE OLD FCST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM EDT WED...THE LATEST MEDIUM RANGE MODELS CONTINUE TO
INDICATE THAT A DEEP MOIST SW FLOW REMAINS IN PLACE OVER THE REGION
THROUGH THE WEEKEND AS WEAK RIDGE OF HIGH PRESSURE PERSISTS OVER THE
SOUTHEASTERN STATES. THE HEIGHTS WILL GRADUALLY FALL SUN INTO MON AS
A STRONG NORTHERN STREAM UPPER LOW PRESSURE MOVES THROUGH THE GREAT
LAKES REGION. A COLD FRONT WILL APPROACH FROM THE NW ON LATE SUNDAY
AND LIKELY STALL IN OR JUST NORTH OF THE AREA THROUGH WEDNESDAY.
HAVE MENTIONED HEALTHY DIURNAL SCATTERED POPS EACH AFTN/EVENING AS
MODEL SOUNDINGS SHOW HIGH PW VALUES (OVER 2 INCHES) AND MODERATE
INSTABILITY ACROSS OUR CWA. TEMPERATURES WILL REMAIN NEAR...OR A
COUPLE DEGREES BELOW SEASONAL AVERAGES THROUGH THE PERIOD.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...SCT CU SHOULD RISE TO AROUND 5 KFT LATER IN THE AFTN. A
WEAK UPPER LOW MAY BRING SOME SHRA/TSTMS TO THE VICINITY IN SEVERAL
HOURS TIME...PROBABLY INTO THE EVENING HOURS. CONFIDENCE ISN/T HIGH
ENOUGH TO ADD A TEMPO GROUP YET...BUT VCSH HAS BEEN ADDED STARTING
IN THE EARLY EVENING. NOT EXPECTING ANY CIG OR VSBY PROBLEMS
OVERNIGHT UNLESS A SHRA HAPPENS TO AFFECT THE AIRFIELD. THE WINDS
SHOULD REMAIN LIGHT OUT OF THE W TO NW THIS AFTN...THOUGH THEY WILL
BE VARIABLE. A MORE S TO SW COMPONENT TO THE FLOW IS EXPECTED
TONIGHT AND THU MORNING.
ELSEWHERE...A WEAK UPPER LOW WILL CROSS THE REGION THIS EVENING.
THIS MAY GIVE RISE TO SCT SHRA/TSTM ACTIVITY STARTING IN THE LATE
AFTN OR EARLY EVENING ACROSS THE FOOTHILLS AND PIEDMONT. STORMS WILL
GO A LITTLE EARLIER AT KAVL. HOWEVER...CONFIDENCE ISN/T HIGH ENOUGH
TO ADD TEMPO/S ANYWHERE YET. WINDS WILL BE LIGHT NW OVER THE NC
ZONES AND OUT OF THE W TO WSW OVER THE UPSTATE. WINDS ACROSS THE
REGION WILL TURN A LITTLE MORE SOUTHERLY TONIGHT. WITH A DAY OF
DRYING UNDER OUR BELTS...LOW CLOUDS AND FOG SHOULD BE FAR LESS
WIDESPREAD TONIGHT. HOWEVER...THE FRENCH BROAD VALLEY SHOULD SEE A
GOOD AMOUNT OF FOG AND LIFR CONDITIONS HAVE BEEN ADDED TO KAVL A
LITTLE LATER THAN THEY DEVELOPED LAST NIGHT.
OUTLOOK...SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL
SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...MCAVOY
SHORT TERM...PM
LONG TERM...JOH
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
411 PM CDT WED AUG 1 2012
.DISCUSSION...
A CLUSTER OF SEVERE STORMS HAS DEVELOPED THIS AFTERNOON OVER
PORTIONS OF WEST TENNESSEE INTO NORTHEAST MISSISSIPPI. THESE
STORMS HAVE FORMED ALONG AN OLD CONVECTIVE OUTFLOW BOUNDARY FROM
LAST NIGHTS STORMS THAT OCCURRED WEST OF THE MISSISSIPPI RIVER.
THESE STORMS CONTINUE TO WORK ON A STRONGLY UNSTABLE AIRMASS
REPRESENTED BY MLCAPE VALUES IN EXCESS OF 3000 J/KG. THE SEVERE
WEATHER THREAT SHOULD MOVE SOUTHEAST OF OUR FORECAST AREA LATER
THIS EVENING. ATTENTION WILL THEN TURN UPSTREAM TOWARDS NORTHEAST
ARKANSAS FOR LATE TONIGHT AS ADDITIONAL CONVECTION MAY DEVELOP
OVER MISSOURI AFTER MIDNIGHT.
THE MID SOUTH WILL REMAIN POSITIONED ALONG THE EASTERN PERIPHERY
OF AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS. A
SERIES OF MID LEVEL SHORTWAVE DISTURBANCES WILL TRAVERSE ACROSS
THE REGION THROUGH THE REMAINDER OF THE WEEK INTO NEXT WEEKEND.
THE FIRST OF SUCH SHORTWAVES IS CURRENTLY EVIDENT ACROSS WESTERN
MISSOURI ALONG WITH AN ASSOCIATED MCV (MESOSCALE CONVECTIVE
VORTEX). MODELS CONTINUE TO INDICATE THAT A LOW LEVEL JET WILL
STRENGTHEN LATER TONIGHT OVER THE SOUTHERN PLAINS AND NOSE INTO A
STALLED SURFACE BOUNDARY STRETCHED ACROSS SOUTHERN MISSOURI INTO
SOUTHERN KENTUCKY. NEW THUNDERSTORM DEVELOPMENT CAN BE EXPECTED
LATER THIS EVENING OVER SOUTHERN MISSOURI WHICH SHOULD DROP
SOUTHEAST INTO NORTHWEST PORTIONS OF THE MID SOUTH AFTER MIDNIGHT
IN NORTHWEST FLOW ALOFT. THIS CLUSTER WILL DIMINISH ACROSS WESTERN
AREAS DURING THURSDAY MORNING BUT NEW CONVECTION MAY INITIATE
DURING PEAK HEATING AGAIN OVER PORTIONS OF THE REGION ALONG
CONVECTIVE OUTFLOWS. HOT AND HUMID WEATHER WILL CONTINUE WITH HEAT
INDEX VALUES AGAIN REACHING OR EXCEEDING 105 DEGREES IN MOST
AREAS. THE HEAT ADVISORY HAS BEEN EXTENDED THROUGH 7 PM THURSDAY.
ANOTHER MORE SIGNIFICANT SHORTWAVE ROUNDS THE TOP OF THE RIDGE ON
THURSDAY NIGHT INTO FRIDAY. THIS SHOULD AGAIN GENERATE ADDITIONAL
SHOWERS AND THUNDERSTORMS. THE ATMOSPHERE SHOULD REMAIN UNSTABLE
SO A FEW SEVERE STORMS CANNOT BE RULED OUT.
THE THIRD MOST SIGNIFICANT WAVE SHOULD APPROACH ON SUNDAY AND
FORCE A COLD FRONT INTO THE REGION. ONCE AGAIN...SCATTERED
CONVECTIVE COVERAGE WITH A SEVERE POTENTIAL CAN BE EXPECTED.
THE FRONT SHOULD DROP INTO SOUTHERN PORTIONS OF THE AREA BY EARLY
NEXT WEEK AS THE UPPER RIDGE REBUILDS BACK INTO THE AREA FROM THE
WEST. THIS WILL BRING AN END TO THE CONVECTIVE CHANCES AND ALLOW
TEMPERATURES TO AGAIN HEAT UP FOR THE END OF THE EXTENDED FORECAST
PERIOD.
JLH
&&
.AVIATION...
18Z TAF SET
SHRAS CONTINUE TO DRIFT SOUTHEASTWARD ACROSS THE CWA. THE SHRAS
ARE ASSOCIATED WITH A DISTURBANCE. BOTH THE HRRR AND NAM SHOW THAT
ACTIVITY MAY BLOSSOM OVER THE NEXT COUPLE OF HOURS AS THE
DISTURBANCE INTERACTS WITH DAYTIME HEATING. AN ANOTHER DISTURBANCE
CURRENTLY OVER EASTERN KANSAS MAY ALSO MOVE INTO THE AREA LATER
TONIGHT FOLLOWED BY ANOTHER ONE BY 12Z. THIS GIVES AT LEAST KJBR
AND POSSIBLY KMEM MULTIPLE CHANCES OF SEEING A SHRA/TSRA.
PINPOINTING TIMING TOO HARD AT THIS POINT. WILL HAVE TEMPO GOING
AT ONSET OF TAFS FOR WHAT IS CURRENTLY GOING ON THEREAFTER WILL
JUST USE VICINITY WORDING. SOME PATCHY FOG MAY ALSO DEVELOP AT
KMKL OVERNIGHT.
KRM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 78 96 77 96 / 20 30 30 40
MKL 74 97 75 93 / 30 20 30 50
JBR 74 95 74 96 / 30 30 40 40
TUP 73 98 74 94 / 80 20 20 40
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR ALCORN-BENTON MS-
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 7 PM CDT THURSDAY FOR CARROLL-CHESTER-
CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-HARDIN-
HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-MCNAIRY-
OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1222 PM CDT WED AUG 1 2012
.UPDATE... /ISSUED 1148 AM CDT WED AUG 1 2012/
UPDATED TO RAISE TEMPERATURES IN THE EAST AND EXPAND CHANCE POPS
EASTWARD FOR THIS AFTERNOON.
&&
.DISCUSSION...
THE MID SOUTH REMAINS ALONG THE EASTERN PERIPHERY OF THE UPPER
RIDGE CENTERED OVER THE SOUTHERN PLAINS. NEW CONVECTION IS NOW
BEGINNING TO GENERATE ALONG OUTFLOW BOUNDARIES GENERATED BY A
DECAYED MCS (MESOSCALE CONVECTIVE SYSTEM) THAT HAS MOVED INTO
WESTERN PORTIONS OF THE MID SOUTH. THE ATMOSPHERE HAS BECOME
MODERATELY UNSTABLE WITH MLCAPES BETWEEN 1500-2500 J/KG...BUT
THERE REMAINS SOME RESIDUAL SUBSIDENCE/CAPPING AS NOTED BY SLOW
DEVELOPMENT OF ONGOING CONVECTION. AS HEATING CONTINUES...THE
ATMOSPHERE SHOULD CONTINUE TO DESTABILIZE ACROSS WESTERN SECTIONS
SO A STRONG STORM CANNOT BE RULED OUT LATER THIS AFTERNOON.
COVERAGE SHOULD STILL REMAIN SCATTERED EVEN ACROSS WESTERN AREAS.
TEMPERATURES WILL BE ABLE TO SOAR INTO THE UPPER 90S IN THE WEST
WITH BREAKS IN CLOUD COVER AND NEAR OR TOP 100 DEGREES EAST OF THE
MISSISSIPPI RIVER WITH LESS CLOUD COVER. HIGH HUMIDITY WILL
CONTINUE WITH LOW TO MID 70S DEWPOINTS PERSISTING.
UPDATES TO THE FORECAST AND GRIDS HAVE BEEN SENT.
JLH
&&
.PREV DISCUSSION... /ISSUED 314 AM CDT WED AUG 1 2012/
CURRENTLY THE MIDSOUTH WAS MOSTLY CLEAR WITH A FEW AREAS SEEING
PATCHY FOG. TEMPERATURES WERE RUNNING A FEW DEGREES COOLER THAN
LAST NIGHT DUE TO THIS RADIATIONAL COOLING...WITH WINDS EITHER
CALM OR LIGHT FROM THE SOUTH. RADAR WAS SHOWING AN AREA OF SHOWERS
AND A FEW THUNDERSTORMS ACROSS SOUTHWEST MISSOURI AND NORTH
CENTRAL ARKANSAS. MOVEMENT OF ACTIVITY WAS TOWARDS THE SOUTHEAST
AT 35 MPH.
FOR TODAY AND THURSDAY...PATCHY FOG EXPECTED TO PERSIST THROUGH 7 AM
THIS MORNING WITH VISIBILITIES AT TIMES DOWN TO ONE MILE. AFTER
SUNRISE THICKER CLOUD COVER FROM UPSTREAM CONVECTION WILL MOVE
INTO THE WESTERN HALF OF THE MIDSOUTH WITH A FEW SHOWERS LIKELY TO
PUSH INTO EASTERN ARKANSAS BEFORE 10 AM. MODELS ARE IN GOOD
AGREEMENT THAT A SHORTWAVE TROUGH SEEN ON WATER VAPOR ACROSS THE
CENTRAL CORN BELT WILL DROP SOUTHEAST THIS AFTERNOON SPREADING THE
RISK FOR ISOLATED STORMS EASTWARD THROUGH THE REMAINDER OF THE
MIDSOUTH COUNTIES. THICKEST CLOUD COVER THOUGH WILL REMAIN OVER THE
WESTERN HALF OF THE CWA. FOR THAT REASON HAVE LOWERED TEMPERATURES
A COUPLE OF DEGREES AND CANCELLED THE EXCESSIVE HEAT WATCH IN THE
SOUTHWEST DELTA COUNTIES. MORE SUN WILL BE SEEN FURTHER EAST WITH
TEMPERATURES LIKELY TO BE SLIGHTLY WARMER THAN YESTERDAY.
DEWPOINTS WILL REMAIN IN THE LOW TO MID 70S WITH HEAT INDICES
TOPPING OUT INTO THE 104-108F RANGE. THUS THE EXTENSION OF THE
HEAT ADVISORY EASTWARD APPEARS TO BE ON TRACK. WILL ALSO LEAVE THE
MENTION OF AN ISOLATED STRONG STORM IN THE HWO...WITH CONVECTION
EXPECTED TO WANE TONIGHT BEHIND THE SHORTWAVE. NEARLY THE SAME
PATTERN IS SHAPING UP FOR THURSDAY WITH THE SLIGHTLY BETTER
CHANCES FOR RAIN REMAINING ALONG AND WEST OF THE MISSISSIPPI
RIVER. TEMPERATURES WILL COOL TO MORE WIDESPREAD MID 90S AND A HEAT
ADVISORY MAY BE NEEDED FOR PORTIONS OF THE MIDSOUTH. WILL ALLOW
THE DAY CREW TO NARROW THAT POSSIBILITY DOWN.
FRIDAY THROUGH SUNDAY...MODELS INDICATE INCREASED RAIN CHANCES THIS
PERIOD AS A MIDWEST COLD FRONT/SHORTWAVE APPROACHES THE REGION.
THE GFS AND NAM ARE MORE BULLISH WITH THE STRENGTH OF BOTH
FEATURES THAN THE EURO AND ARE SLIGHTLY FASTER. HAVE TAKEN A BLEND
OF THE MODELS WITH POPS EXPECTED IN THE 30 TO 50 PERCENT RANGE
EACH DAY. A BETTER CHANCE OF A SEVERE STORM IS ALSO NOTED FOR THIS
TIME FRAME. TEMPERATURES WILL HOLD INTO THE LOW AND MID 90S WITH
A MIX OF CLOUDS AND SUN. DEWPOINTS SHOULD REMAIN IN THE 70S...WITH
UPPER 60S DIPPING INTO THE NORTHERN COUNTIES BEHIND THE FRONT BY
SUNDAY. FOR NOW...HEAT INDICES APPEAR TO BE BELOW 104 DEGREES.
EXTENDED PERIOD...LINGERING CONVECTION IS ANTICIPATED ACROSS THE FAR
SOUTH ON MONDAY AND TUESDAY AS THE FRONT DISSIPATES OVER THE MID
DEEP SOUTH. LIGHT NORTH WINDS WILL TEMPORARILY DRY OUT THE
NORTHERN HALF OF THE MIDSOUTH...WITH HIGH TEMPERATURES REMAINING
IN THE 90 TO 95 DEGREE RANGE.
JAB
&&
.AVIATION...
18Z TAF SET
SHRAS CONTINUE TO DRIFT SOUTHEASTWARD ACROSS THE CWA. THE SHRAS
ARE ASSOCIATED WITH A DISTURBANCE. BOTH THE HRRR AND NAM SHOW THAT
ACTIVITY MAY BLOSSOM OVER THE NEXT COUPLE OF HOURS AS THE
DISTURBANCE INTERACTS WITH DAYTIME HEATING. AN ANOTHER DISTURBANCE
CURRENTLY OVER EASTERN KANSAS MAY ALSO MOVE INTO THE AREA LATER
TONIGHT FOLLOWED BY ANOTHER ONE BY 12Z. THIS GIVES AT LEAST KJBR
AND POSSIBLY KMEM MULTIPLE CHANCES OF SEEING A SHRA/TSRA.
PINPOINTING TIMING TOO HARD AT THIS POINT. WILL HAVE TEMPO GOING
AT ONSET OF TAFS FOR WHAT IS CURRENTLY GOING ON THEREAFTER WILL
JUST USE VICINITY WORDING. SOME PATCHY FOG MAY ALSO DEVELOP AT
KMKL OVERNIGHT.
KRM
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 99 78 97 77 / 30 20 30 20
MKL 98 72 97 73 / 20 20 20 20
JBR 97 75 96 76 / 30 30 30 20
TUP 98 73 98 74 / 20 10 20 20
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ALCORN-BENTON MS-
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CARROLL-CHESTER-
CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-HARDIN-
HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-MCNAIRY-
OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
325 PM CDT WED AUG 1 2012
.VERY SHORT TERM...TONIGHT AND THURSDAY.
CURRENT ELEVATED CONVECTION ACROSS NORTHERN WISCONSIN ASSOCIATED
WITH LOW LEVEL WARM AIR ADVECTION AND NOSE OF 30 KNOT PLUS WESTERLY
LOW LEVEL JET. THIS CONVECTION SHOULD SHIFT SOUTHEAST TOWARD CENTRAL
TO EAST CENTRAL WISCONSIN BUT WEAKEN...AS CAPPED AIRMASS LINGERS IN
SOUTHERN WISCONSIN. THIS IS SUPPORTED BY 16Z RUN OF HRRR MODEL. MAY
SEE SOME LEFTOVER DEBRIS CLOUDS MOVE THROUGH THE AREA LATER THIS
AFTERNOON INTO THE EARLY EVENING. WILL GO DRY FOR NOW IN THE FAR
NORTHERN COUNTIES THROUGH THE REST OF THE DAY.
SURFACE COLD FRONT SHIFTS SOUTHEAST TOWARD THE AREA TONIGHT...THEN
SLOWLY SOUTHWARD THROUGH THE AREA ON THURSDAY. WARM AIR ADVECTION
CONTINUES AHEAD OF THE FRONT TONIGHT...WITH THE RIGHT REAR QUADRANT
OF A 250MB JET STREAK PUSHING THROUGH LATER TONIGHT INTO THURSDAY
MORNING.
AREA FORECAST SOUNDINGS FROM NAM AND RAP SHOWING CAP FOR SURFACE
BASED PARCELS TONIGHT AND THURSDAY...WITH MODEST ELEVATED CAPES
AROUND 500 J/KG. LOW LEVELS REMAIN DRY...WITH SOME MID LEVEL
MOISTURE MOVING INTO THE AREA LATER TONIGHT INTO THURSDAY. HRRR
MODEL TRIES TO DEVELOP AN AREA OF CONVECTION IN SOUTHERN MINNESOTA
ALONG COLD FRONT AND BRING IT TOWARD THE WESTERN COUNTIES AFTER
MIDNIGHT TONIGHT.
FOR NOW...WILL BRING IN CHANCE POPS FROM NORTHWEST TO SOUTHEAST
TONIGHT. LINGERED CHANCE POPS THURSDAY MORNING IN THE NORTHERN
COUNTIES...LOWER TO THE SOUTH...WITH LOWER END POPS DURING THE
AFTERNOON.
TEMPERATURES WILL BE TRICKY DEPENDING ON HOW MUCH MID LEVEL
CLOUDINESS DEVELOPS/MOVES THROUGH THE AREA. WENT SOMEWHAT LOWER THAN
WARM 925MB TEMPERATURES FROM NAM...UPPER 60S TONIGHT WITH UPPER 80S
TO LOWER 90S THURSDAY. LAKE BREEZE IN THE AFTERNOON
.SHORT TERM...THURSDAY NIGHT THROUGH SATURDAY.
WEAK Q-VECTOR CONVERGENCE AND FRONTEGENETICAL FORCING MAY RESULT IN
A FEW SHOWERS OR THUNDERSTORMS LINGERING INTO THURSDAY EVENING OVER
THE NORTHERN AREAS. BOTH ECMWF AND NAM SHOW THIS WEAK FORCING...BUT
WILL BE LIMITED BY DRYING MID LEVELS. SLIGHTLY BETTER FORCING
FARTHER NORTH...SO WL ONLY GO WITH SCHC POPS FOR NOW.
LOW LEVEL MIXING SHOULD PREVENT SIGNIFICANT FOG LATER THURSDAY
NIGHT. SHORT WAVE RIDGING AHEAD OF NEXT WEATHER SYSTEM IS EXPECTED
TO BRING A PLEASANT DAY FOR FRIDAY...WITH UNSETTLED CONDITIONS
FOCUSED TO THE SOUTH AND WEST OF WI.
SHORT TERM GUIDANCE IN SURPRISINGLY GOOD AGREEMENT ON MORE VIGOROUS
SHORT WAVE TROF MOVING ACROSS SOUTHERN CANADA AND THE WESTERN
GTLAKES FRIDAY NIGHT THROUGH SATURDAY NIGHT. ASSOCIATED LOW
PRESSURE WILL DRAG A COLD FRONT ACROSS SOUTHERN WI AND LAKE MICHIGAN
DURING PEAK HEATING OF THE AFTN AND EVE. WITH SFC DEWPTS LIKELY TO
BE IN THE MID 60S TO LOW 70S...SFC BASED CAPE VALUES MAY CLIMB TO
ABV 3000 J/KG. BULK SHEAR WILL BE STRONG ENOUGH...IN THE 25 TO 40KT
RANGE. LOW LEVEL JETS REMAIN FOCUSED FARTHER SOUTH ALONG WARM FRONT
AND NORTH...CLOSER TO LOW PRESSURE. HENCE WL KEEP POPS IN HIGH
CHANCE CATEGORY INTO SAT NGT...AND MENTION POSSIBILITY OF SEVERE IN
HAZARDOUS WEATHER OUTLOOK.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY.
VIGOROUS SHORT WAVE TROUGH AND COLD FRONT PUSH EAST OF WISCONSIN
SATURDAY NIGHT...USHERING COOLER AND DRY CONDITIONS INTO THE REGION
FOR SUNDAY AND MONDAY. GFS ENSEMBLES IN FAIRLY GOOD AGREEMENT ON
THIS SCENARIO.
EXTENDED OUTLOOK TURNS MORE MURKY HEADING INTO MID-WEEK AS BOTH
ECMWF AND GFS HAVE BEEN FLIP-FLOPPING ON UPPER LEVEL STEERING FLOW.
LATEST SOLUTIONS HAVE TRENDED TOWARD MORE PROGRESSIVE WEST-NORTHWEST
STEERING FLOW FOR THE LATER HALF OF THE PERIOD. UKMT...GFS AND
ECMWF SOLUTIONS CARRY WEAK FRONTAL BOUNDARY THROUGH WI SOMETIME IN
THE MON NGT/TUESDAY TIME FRAME...WITH FRONT POSSIBLY BECOMING
STATIONARY ACROSS THE REGION...BUT CONFIDENCE LOW AS EXTENDED
GUIDANCE HAVING ISSUES WITH TIMING AND STRENGTH OF SHORT WAVE
TROFFING MOVING INTO WESTERN CONUS. AFTER COOLER...MORE SEASONAL
PERIOD ON SUNDAY AND MONDAY...85H TEMPS WARM BACK TO AROUND 20C.
GFS 5DAY ANOMOLIES SHOW RIDGING AND WARMER TEMPERATURES EXPANDING
BACK INTO THE UPPER MIDWEST LATER NEXT WEEK AHEAD OF LONG WAVE
TROUGH AMPLIFICATION IN THE EASTERN PAC/NORTHWEST CONUS.
&&
.AVIATION /00Z TAFS/...VFR CONDITIONS EXPECTED THROUGH THURSDAY
ACROSS TAF SITES. FEW TO SCATTERED DIURNAL CUMULUS AT EASTERN TAF
SITES SHOULD DISSIPATE BY SUNSET. LIGHT SOUTH TO SOUTHWEST WINDS
EXPECTED AT MADISON DURING THIS TIME...WITH LIGHT SOUTHEAST WINDS
EVENTUALLY REACHING MILWAUKEE AND KENOSHA BY 22Z TO 23Z WEDNESDAY.
SOME MID LEVEL CLOUDS FROM STORMS TO THE NORTH MAY SHIFT THROUGH TAF
SITES LATE THIS AFTERNOON AND EARLY THIS EVENING.
SCATTERED TO BROKEN MIDDLE TO HIGH CLOUDS SHOULD GRADUALLY MOVE INTO
THE AREA LATER TONIGHT AND THURSDAY. COLD FRONT WILL SHIFT SOUTHEAST
TOWARD TAF SITES LATE TONIGHT...THEN SLIDES SOUTHWARD THROUGH TAF
SITES THURSDAY. MAY SEE SHOWERS AND STORMS APPROACH MADISON BETWEEN
06Z AND 12Z THURSDAY...AND ACROSS ALL SITES THURSDAY. HOWEVER...WILL
HOLD OFF MENTION IN TAFS FOR NOW DUE TO LOW CONFIDENCE IN AREAL
COVERAGE AND TIMING.
LIGHT WINDS WILL SHIFT TO THE NORTHEAST/EAST IN THE WAKE OF THE COLD
FRONT IN THE LATE MORNING AND EARLY AFTERNOON THURSDAY.
&&
.CONFIDENCE...
TONIGHT AND THURSDAY...MEDIUM
THURSDAY NIGHT...LOW TO MEDIUM.
FRIDAY AND FRIDAY NIGHT...MEDIUM.
SATURDAY AND SATURDAY NIGHT...MEDIUM.
SUNDAY AND MONDAY...MEDIUM TO HIGH.
TUESDAY AND WEDNESDAY...LOW.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
VERY SHORT TERM/AVIATION...WOOD
SHORT TERM/LONG TERM...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
108 PM CDT WED AUG 1 2012
.SHORT TERM...
1148 AM CDT WED AUG 1 2012
HAVE UPDATED THE FORECAST FOR CURRENT TRENDS FOR THE AFTERNOON AND
ALSO A BIGGER INCREASE TO RAIN CHANCES TONIGHT.
MONITORING CURRENT TSRA/SHRA ACTIVITY OVER MN WHICH SEEMS TO BE TIED TO
THE 700MB LEVEL FORCING. THE 700MB TRANSPORT IS CONVERGENT ALONG
ITS EAST SIDE IN THE MAXIMIZED THETA-E ADVECTION AREA AT THE SAME
LEVEL AND THIS IS WHERE ACTIVITY HAS BEEN LIVING. USING RAP 01.15
RUN...THIS WOULD SUGGEST THE POTENTIAL FOR THIS TO SHIFT EAST
ACROSS THE FORECAST AREA IN THE AFTERNOON. WILL CONTINUE TO
MONITOR THIS HIGHER-BASED ACTIVITY AND MAY NEED TO UPDATE TO
HIGHER RAIN CHANCES. 12Z KMPX RAOB SUGGEST ABOUT 800 J/KG OF CAPE
FOR A PARCEL LIFTED FROM 700MB AND THIS WAS ENOUGH TO GENERATE A
HIGH-BASED TSRA WITH WIND DAMAGE OVER KMPX FORECAST AREA IN LAST
HOUR. GOES IR IMAGERY SUGGESTS THESE TOPS ARE COOLING IN SOME
AREAS BUT WARMING IN OTHERS. HAVE INCREASED CLOUD A BIT IN THE
NORTHWEST TODAY.
LATE THIS AFTERNOON AND EVENING WILL SEE A NICE INCREASE IN AN E-W
ORIENTED FRONTOGENESIS BAND IN THE 900-700 MB LAYER MOVING IN
FROM THE WEST/NORTHWEST. THIS WILL BE INCREASING AS THE CAPE IS
MAXIMIZING...PROVIDING A NICE LOW LEVEL TRIGGER FOR TSRA. TAKING A
0-2KM AGL MIXED LAYER PARCEL GENERATES 2000 J/KG ALONG THE FRONT
TO THE NORTHWEST...WITH THE 0-1KM LAYER PROVIDING 2500 J/KG OF
CAPE. SO...THE INSTABILITY WILL BE THERE AND FORCING SUGGESTS TSRA
WILL DEVELOP NW OF FORECAST AREA LATE AFTERNOON AND SHIFT IN THIS
EVENING. HRRR RUNS AGREE WITH THIS IDEA VIA REFLECTIVITY. ANY
STRONGER STORM COULD PRODUCE DAMAGING WIND GUSTS WITH
INVERTED-V...STEEP LAPSE RATE ENVIRONMENT THAT WILL BE OUT THERE
BY LATE AFTERNOON. HRRR HOURLY WIND GUST SPEED SUGGESTS 70 KTS
NEAR THE SURFACE ASSOCIATED WITH TSRA IN THE MODEL. SOMETIMES THIS
IS A GOOD INDICATOR FOR SEVERE POTENTIAL.
WITH 01.12Z AND 01.06Z NAM SUGGESTING FRONTOGENESIS AND 01.09Z
SREF PAINTING HIGHER RAIN PROBABILITIES FOR THE OVERNIGHT WITH
THIS FORCING AND STILL SOME CAPE REMAINING. SO...HAVE BUMPED RAIN
CHANCES MOST AREAS OVERNIGHT WITH MAX BEING ALIGNED ALONG I-90.
SHOULD SEE SOME STEADY RAINS WITH EMBEDDED TSRA OVERNIGHT.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
424 AM CDT THU AUG 1 2012
ON SATURDAY...THE STRONG SHORT WAVE TROUGH WILL MOVE ACROSS NORTHERN
MINNESOTA AND NORTHERN WISCONSIN. WHILE THE 0-6 KM SHEAR IS GREATER
THAN 50 KNOTS...PROFILERS SHOW THAT THAT MUCH OF THIS SHEAR IS
ASSOCIATED WITH SPEED SHEAR. THIS BRINGS UP THE QUESTION WHETHER
THIS SHEAR WILL OUTWEIGH THE AMOUNT OF INSTABILITY AVAILABLE BEHIND
THE FRONT. IF THIS DOES INDEED OCCUR...THE STORMS MAY GET SHEARED
APART...THUS LIMITING OUR SEVERE WEATHER POTENTIAL.
BEYOND THIS TIME PERIOD...IT LOOKS LIKE HIGH PRESSURE WILL PROVIDE
DRY WEATHER INTO EARLY NEXT WEEK. IN ADDITION...TEMPERATURES WILL
ONCE AGAIN CLIMB WELL ABOVE NORMAL.
&&
.AVIATION...THROUGH 18Z THURSDAY
108 PM CDT WED AUG 1 2012
INCREASING TSRA PROBABILITIES FOR THE TAF SITES THIS EVENING. A
COLD FRONT MOVING INTO MN WILL WORK WITH GROWING INSTABILITY LATE
IN THE AFTERNOON TO INITIATE TSRA ACTIVITY OVER
SOUTHCENTRAL/CENTRAL MN BY LATE AFTERNOON. THESE STORMS ARE
EXPECTED TO MOVE SOUTHEAST AND COULD AFFECT THE TAF SITES THIS
EVENING. HAVE KEPT VCTS AT THE TAF SITES AS CONFIDENCE IS NOT HIGH
ENOUGH ON THE COVERAGE OF STORMS THAT WILL OCCUR TO MOVE TO
PREVAILING/TEMPO TSRA. HOWEVER...WILL BE MONITORING RADAR FOR
DEVELOPMENT AND UPDATING THE TAF SHOULD CONFIDENCE INCREASE THAT
THE AIRFIELD WOULD BE HIT. FOR NOW...HAVE PUSHED BACK TIMING OF
VCTS TO EVENING.
THE STRONGER EVENING STORMS COULD PACK A WIND GUST THREAT TO 65KTS
SHOULD A DIRECT HIT TO THE AIRFIELD TAKE PLACE. THIS IS MAINLY
BECAUSE OF THE VERY DRY AND DEEP SUB-CLOUD LAYER WHICH WILL
ENHANCE MICROBURST TYPE THREATS.
LIFT WILL CONTINUE TO GROW AND IT APPEARS THIS WILL BE FOCUSED
OVER THE TAF SITES OVERNIGHT AS FRONTOGENESIS IN THE 900-600 MB
LAYER INCREASES. WITH SOME INSTABILITY LEFT OVERNIGHT...A BAND OF
SHRA/RA IS EXPECTED AND HAVE NOW INCLUDED THIS IN THE FORECAST.
SHOULD THE RAIN CONTINUE OVER THE TAF SITES FOR MANY
HOURS...LOWER CIGS/VSBYS WOULD RESULT AND WHILE KRST NOW WILL
INCLUDE MVFR...FUTURE FORECASTS MAY NEED TO LOWER CONDITIONS
AGAIN AT BOTH TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
424 AM CDT THU AUG 1 2012321 PM CDT TUE JUL 31 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BOYNE
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1233 PM CDT WED AUG 1 2012
.UPDATE...
SIMILAR SITUATION TO YESTERDAY. HIGH PRESSURE SLIDING OFF TO OUR
SOUTHEAST CONTINUES TO INFLUENCE THE WEATHER IN OUR CWA...EXPECT
QUIET CONDITIONS IN THE NEAR-TERM. NOT MANY CHANGES MADE TO THE
FORECAST PACKAGE IN THE FIRST PERIOD. TEMPERATURE TREND WAS
ADJUSTED...HOWEVER...HIGHS WERE LEFT AS IS. HIGHS WILL BE WARMER
THAN YESTERDAY BY A FEW DEGREES GIVEN WARMER TEMPS ALOFT AND LESS
CU. GIVEN THE INSOLATION AND ADEQUATE MIXING...TEMPS SHOULD MIX
DOWN FROM AT LEAST 925 HPA. 925 HPA TEMPS ON ECMWF ARE AROUND
25-28 C THAT YIELDS AROUND 89 TO 94 F...AS IS FORECASTED. NAM IS
RUNNING TOO WARM ALOFT AS HAS BEEN SEEN IN THE PAST. RAP MODEL
SOUNDINGS SHOW MIXING THROUGH AT LEAST 900 HPA. VIS SAT AND SFC OBS
CURRENTLY SHOW MOSTLY SUNNY SKIES WITH A FEW CU INLAND AND SCT CU
IN LIMITED PORTIONS OF THE LAKE SHORE COUNTIES. NOT ANTICIPATING MUCH
DIURNAL CU DEVELOPMENT TODAY. SHOULD SEE ONLY A FEW CU INLAND WITH
SCT CU LIMITED TO THE LAKE SHORE COUNTIES...AS MODEL SOUNDINGS ARE
NOTABLY MORE DRIER INLAND AT THE LOWER LEVELS.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS EXPECTED THROUGH THURSDAY ACROSS TAF SITES. SCATTERED
DIURNAL CUMULUS SHOULD BE LIMITED TO EASTERN TAF SITES...CLOSER TO
HIGHER LOW LEVEL MOISTURE. MOSTLY SUNNY SKIES AND LIGHT SOUTH TO
SOUTHWEST WINDS EXPECTED AT MADISON THROUGH THE AFTERNOON. LIGHT
SOUTH TO SOUTHWEST WINDS WILL SHIFT SOUTHEAST AT MILWAUKEE AND
KENOSHA BY 19Z THIS AFTERNOON...MAYBE REACHING WAUKESHA BY 22Z.
SCATTERED TO BROKEN MIDDLE TO HIGH CLOUDS SHOULD GRADUALLY MOVE INTO
THE AREA LATER TONIGHT AND THURSDAY. WEAK COLD FRONT WILL SHIFT
SOUTHEAST TOWARD TAF SITES LATE TONIGHT...THEN SLIDES SOUTHWARD
THROUGH TAF SITES THURSDAY. MAY SEE SHOWERS AND STORMS APPROACH
MADISON BETWEEN 06Z AND 12Z THURSDAY...AND ACROSS ALL SITES
THURSDAY. HOWEVER...WILL HOLD OFF MENTION IN TAF DUE TO LOW
CONFIDENCE IN AREAL COVERAGE AND TIMING.
WINDS WILL SHIFT TO THE NORTH TO NORTHEAST IN THE WAKE OF THE COLD
FRONT BETWEEN 15Z AND 19Z THURSDAY.
&&
.PREV DISCUSSION... /ISSUED 325 AM CDT WED AUG 1 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
EARLY THIS MORNING THERE WILL BE FOG IN LOW SPOTS AND RIVER VALLEYS
UNTIL 9 AM...ESPECIALLY EAST OF MADISON WHERE RAIN FELL OVERNIGHT
MONDAY. OTHERWISE QUIET WEATHER TODAY AS RIDGE OF HIGH PRESSURE
FROM IA TO WI TO LOWER MI PIVOTS TO AN IL TO LOWER MI LINE BY SUNSET.
UPSTAIRS A WEAK SHORT WAVE IS PROGGED TO SLIDE SOUTHEAST OVER WI
TODAY...WITH NO LOW-LEVEL EFFECTS DUE TO DRY AIR BELOW 10 THSD FT
AGL. MODELS VARY ON TIMING AND POSITION OF THIS SHORT WAVE...BUT
THAT DOESN/T MATTER ANYWAY.
SHORT-WAVE RIDGING ALOFT ALSO OCCURRING TODAY FOLLOWED BY THE
APPROACH OF A MORE SIGNIFICANT SHORT-WAVE BY LATE TONIGHT INTO WI.
BY LATE TONIGHT MODELS BRING ASSOCIATED SURFACE FRONT DOWN INTO
SOUTHERN WI...WITH NAM BEING THE FASTEST AND ECMWF THE WEAKEST. ALL
MODELS SHOW GENERATION OF PRECIP AFTER MIDNIGHT IN SOUTHERN WI...BUT
VARY ON TIMING/PLACEMENT/AMOUNTS. INTERESTINGLY... THE NAM KEEPS MY
COUNTY WARNING AREA /CWA/ DRY TONIGHT...THE GFS KEEPS MOST OF THE
CWA DRY...THE ECMWF HAS PCPN OVER ALL BUT THE SOUTHERN PART OF MY
CWA...AND THE CANADIAN BRINGS CONVECTION INTO SOUTHWEST AND
SOUTHCENTRAL WI COUNTIES BETWEEN 09 AND 12Z. SO WILL GO WITH CHANCE
OF SHOWERS/STORMS FOR TONIGHT OVER ALL BUT SOUTHEAST PART OF MY
CWA.
THURSDAY AND THURSDAY NIGHT - CONFIDENCE...MEDIUM
SURFACE BOUNDARY PROGGD TO SHIFT INTO FAR SRN WI OR NRN IL. NAM IS
QUICKER WITH FROPA ESTABLISHING THE NE FLOW SOONER. MEANWHILE
850/925 BAROCLINIC ZONE REMAINS WITH SOME MID LEVEL FRONTOGENETICAL
FORCING. BUFKIT SOUNDINGS SHOW SOME ELEVATED CAPE WITH LOW LEVELS
RATHER UNIMPRESSIVE MOISTURE WISE. SURFACE FORCING WILL NOT
INITATE PRECIP. WILL BE POST FRONTAL DEVELOPMENT WITHIN THE
REGION OF BEST MID LEVEL FRONTAL FOCRING. HUGE DIFFERENCES
BETWEEN GFS AND NAM MOS DEW POINTS AS MUCH AS 14 DEGREES. GFS OF
COURSE TOO MOIST SHOWING DEWS IN THE MID 70S. FAIRLY SWIFT WNW
UPPER FLOW CARRYING A SHORTWAVE THOUGH. SOME TIMING DIFFERENCES
WITH THIS. 12Z ECMWF SUGGESTS THIS WOULD CONTRIBUTE TO FORCING
THURSDAY NIGHT. THOUGH WITH FRONTOGENETICAL FORCING PROGGD TO
SHIFT FURTHER NORTH. WILL GO WITH SMALL POPS.
FRIDAY - CONFIDENCE...MEDIUM
UPPER FLOW BECOMES A BIT MORE WSW. A RIPPLE HERE AND THERE. ELEVATED
INSTABILITY APPEARS THOUGH SOUNDINGS ARE QUITE DRY IN THE LOW
LEVELS. NO 850/925 FORCING TO SPEAK OF. BETTER LOW LEVEL JET ACTION
TO THE WEST OF HERE WITH CWASP MAX TO OUR NORTHWEST.
SATURDAY AND SATURDAY NIGHT - CONFIDENCE...MEDIUM
VIGOROUS 500 MILLIBAR TROUGH DIGS INTO THE WESTERN GREAT LAKES.
FROPA AND BEST DIFFERENTIAL CYCLONIC VORTICITY ADVECTION ARRIVE
SATURDAY AFTERNOON/EVENING. MODELS HAVE TRENDED A BIT FASTER WITH
ALL SUGGESTING T-STORMS WILL BE IN THE AREA BEFORE 00Z SUNDAY.
DECENT RIGHT REAR QUADRANT DIVERGENCE ARRIVES INTO CWA DURING THE
AFTERNOON SATURDAY. BETTER LOW LEVEL JET FOCUSING IS NORTH WITH
STRONGEST DYNAMICS/VORTICITY PUNCH FOCUSING TO THE NORTH AS WELL.
CWASP NUMBERS ARE ALSO HIGHEST TO OUR NORTH AND NORTHEAST. HOWEVER
VERY WARM AND HUMID AIRMASS IN PLACE WITH FAVORABLE PLACEMENT OF
UPPER JET SUGGEST SEVERE WEATHER POTENTIAL IS STILL THERE. 0-6KM
SHEAR IS 40 KNOTS PLUS WITH FAVORABLE 576DM 1000-500 THICKNES ACROSS
CWA. 700-500 MILLIBAR LAPSE RATES AT LEAST 7C/KM...SO SOME FAVORABLE
PARAMETERS EXIST.
SUNDAY THROUGH TUESDAY - CONFIDENCE...MEDIUM
UPPER TROUGH SHIFTS EAST SUNDAY WITH NVA AND HIGH PRESSURE TAKING
HOLD INTO MONDAY. 00Z ECMWF THREW A LITTLE CURVE FOR MONDAY NIGHT
WITH A WAVE/WEAK FRONT SNEAKING IN THOUGH CONSENSUS WAS TO HOLD OFF
ON THIS FEATURE AT THIS POINT. 925 TEMPS START TO RAMP BACK UP A BIT
BY TUESDAY...REACHING THE MID/UPPER 20S CELSIUS.
AVIATION/12Z TAFS/...FOG ISSUES UNTIL ABOUT 14Z /9 AM/ THIS MORNING...
MAINLY EAST OF MADISON WHERE MORE RAIN FELL OVERNIGHT MONDAY.
VSBYS BOUNCED UP AND DOWN AT WEST BEND FROM 3/4 TO 10 MILES. WILL
PROBABLY GO WITH VARIATIONS OF 1 TO 3 MILES IN THE KUES AND KENW
TAFS AND 5 MI IN THE KMKE TAF. SURFACE HIGH PRESSURE RIDGE MOVES
SOUTHEAST OUT OF WI TODAY ALLOWING FOR SOUTH WINDS TO DEVELOP AT
SURFACE. OTHERWISE THE USUAL DIURNAL CUMULUS CLOUDS AROUND 5 THSD
FT AGL TODAY WITH HEATING...BUT ONLY SCATTERED AND FEWER IN
NUMBERS COMPARED TO TUESDAY/S AMOUNTS. MULTIPLE LAYERS OF MID AND
UPPER LEVEL CLOUDS BY LATE TONIGHT...WITH SCATTERED CUMULUS BELOW.
WITH APPROACH OF A SURFACE FRONT LATE TONIGHT WILL HAVE TO HAVE A
CHANCE OF STORMS. ONLY KENW WILL NOT HAVE A CHANCE OF STORMS LATE
TONIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...KAPELA
THURSDAY THROUGH TUESDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 AM CDT WED AUG 1 2012
.SHORT TERM...
1148 AM CDT WED AUG 1 2012
HAVE UPDATED THE FORECAST FOR CURRENT TRENDS FOR THE AFTERNOON AND
ALSO A BIGGER INCREASE TO RAIN CHANCES TONIGHT.
MONITORING CURRENT TSRA/SHRA ACTIVITY OVER MN WHICH SEEMS TO BE TIED TO
THE 700MB LEVEL FORCING. THE 700MB TRANSPORT IS CONVERGENT ALONG
ITS EAST SIDE IN THE MAXIMIZED THETA-E ADVECTION AREA AT THE SAME
LEVEL AND THIS IS WHERE ACTIVITY HAS BEEN LIVING. USING RAP 01.15
RUN...THIS WOULD SUGGEST THE POTENTIAL FOR THIS TO SHIFT EAST
ACROSS THE FORECAST AREA IN THE AFTERNOON. WILL CONTINUE TO
MONITOR THIS HIGHER-BASED ACTIVITY AND MAY NEED TO UPDATE TO
HIGHER RAIN CHANCES. 12Z KMPX RAOB SUGGEST ABOUT 800 J/KG OF CAPE
FOR A PARCEL LIFTED FROM 700MB AND THIS WAS ENOUGH TO GENERATE A
HIGH-BASED TSRA WITH WIND DAMAGE OVER KMPX FORECAST AREA IN LAST
HOUR. GOES IR IMAGERY SUGGESTS THESE TOPS ARE COOLING IN SOME
AREAS BUT WARMING IN OTHERS. HAVE INCREASED CLOUD A BIT IN THE
NORTHWEST TODAY.
LATE THIS AFTERNOON AND EVENING WILL SEE A NICE INCREASE IN AN E-W
ORIENTED FRONTOGENESIS BAND IN THE 900-700 MB LAYER MOVING IN
FROM THE WEST/NORTHWEST. THIS WILL BE INCREASING AS THE CAPE IS
MAXIMIZING...PROVIDING A NICE LOW LEVEL TRIGGER FOR TSRA. TAKING A
0-2KM AGL MIXED LAYER PARCEL GENERATES 2000 J/KG ALONG THE FRONT
TO THE NORTHWEST...WITH THE 0-1KM LAYER PROVIDING 2500 J/KG OF
CAPE. SO...THE INSTABILITY WILL BE THERE AND FORCING SUGGESTS TSRA
WILL DEVELOP NW OF FORECAST AREA LATE AFTERNOON AND SHIFT IN THIS
EVENING. HRRR RUNS AGREE WITH THIS IDEA VIA REFLECTIVITY. ANY
STRONGER STORM COULD PRODUCE DAMAGING WIND GUSTS WITH
INVERTED-V...STEEP LAPSE RATE ENVIRONMENT THAT WILL BE OUT THERE
BY LATE AFTERNOON. HRRR HOURLY WIND GUST SPEED SUGGESTS 70 KTS
NEAR THE SURFACE ASSOCIATED WITH TSRA IN THE MODEL. SOMETIMES THIS
IS A GOOD INDICATOR FOR SEVERE POTENTIAL.
WITH 01.12Z AND 01.06Z NAM SUGGESTING FRONTOGENESIS AND 01.09Z
SREF PAINTING HIGHER RAIN PROBABILITIES FOR THE OVERNIGHT WITH
THIS FORCING AND STILL SOME CAPE REMAINING. SO...HAVE BUMPED RAIN
CHANCES MOST AREAS OVERNIGHT WITH MAX BEING ALIGNED ALONG I-90.
SHOULD SEE SOME STEADY RAINS WITH EMBEDDED TSRA OVERNIGHT.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
424 AM CDT THU AUG 1 2012
ON SATURDAY...THE STRONG SHORT WAVE TROUGH WILL MOVE ACROSS NORTHERN
MINNESOTA AND NORTHERN WISCONSIN. WHILE THE 0-6 KM SHEAR IS GREATER
THAN 50 KNOTS...PROFILERS SHOW THAT THAT MUCH OF THIS SHEAR IS
ASSOCIATED WITH SPEED SHEAR. THIS BRINGS UP THE QUESTION WHETHER
THIS SHEAR WILL OUTWEIGH THE AMOUNT OF INSTABILITY AVAILABLE BEHIND
THE FRONT. IF THIS DOES INDEED OCCUR...THE STORMS MAY GET SHEARED
APART...THUS LIMITING OUR SEVERE WEATHER POTENTIAL.
BEYOND THIS TIME PERIOD...IT LOOKS LIKE HIGH PRESSURE WILL PROVIDE
DRY WEATHER INTO EARLY NEXT WEEK. IN ADDITION...TEMPERATURES WILL
ONCE AGAIN CLIMB WELL ABOVE NORMAL.
&&
.AVIATION...TODAY AND TONIGHT
638 AM CDT WED AUG 1 2012
FOCUS IS ON THUNDERSTORM CHANCES THIS AFTERNOON THROUGH TONIGHT
ASSOCIATED WITH COLD FRONT DROPPING SOUTH ACROSS THE TAF SITES.
DEEP MIXING AND SOUTHERLY WINDS WILL BE FOUND FOR MUCH OF
TODAY...WITH COULD LEAD TO SOME GUSTY WINDS UP TO 20 KTS AT BOTH
KRST/KLSE. BY 01.22Z...SURFACE FRONT SHOULD BE ALONG A FSD TO MSP TO
HYR LINE AND SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
RIGHT ALONG AND BEHIND IT...ASSOCIATED WITH GREATEST 700 TO 850 MB
FRONTOGENESIS. 700 MB MOISTURE TRANSPORT IS LIMITED HOWEVER...AND
THERE IS QUESTION AS TO COVERAGE OF STORMS SO FEEL MAINTAINING VCTS
AND VFR CONDITIONS AT BOTH KRST/KLSE IS APPROPRIATE. THE LOWEST
2-2.5 KM ARE VERY DRY / INVERTED V SOUNDING / SO ANY STORMS THAT
DO DEVELOP COULD PRODUCE STRONG WINDS...ALONG WITH MVFR VISIBILITIES.
BEST TIMING LOOKS TO BE FROM 23Z THROUGH 06Z...THOUGH LATEST NAM
KEEPS STORMS ALONG SOUTHERN MINNESOTA / WESTERN WISCONSIN THROUGH
09Z. WINDS WILL GRADUALLY TURN TO THE NORTH BY 02.12Z AS FRONT
DROPS SOUTH OF TAF SITES...WITH BROKEN MID LEVEL CLOUDS LINGERING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
424 AM CDT THU AUG 1 2012321 PM CDT TUE JUL 31 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BOYNE
AVIATION...ZT