Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/22/13
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
840 AM MST SAT JUL 20 2013
.SYNOPSIS...
A VERY MOIST AIRMASS IS EXPECTED TO REMAIN OVER THE REGION AS A LOW
PRESSURE SYSTEM IN MEXICO MOVES OFF WELL TO SOUTH AND WEST. ABOVE
NORMAL RAIN CHANCES AND BELOW NORMAL TEMPERATURES ARE EXPECTED
THROUGH MONDAY. SOMEWHAT DRIER AND WARMER WEATHER IS EXPECTED FROM
TUESDAY ONWARD THROUGH THE END OF NEXT WEEK AS HIGH PRESSURE BECOMES
REESTABLISHED ACROSS THE ROCKIES.
&&
.DISCUSSION...
AFTER A RATHER ACTIVE NIGHT...WITH WIDESPREAD RAINFALL BEING
REPORTED FROM AN MCS THAT MOVED FROM THE NORTHERN AND WESTERN
PORTION OF THE PHOENIX AREA ACROSS SOUTHWEST ARIZONA...AND INTO THE
LOWER COLORADO RIVER VALLEY...THINGS HAVE QUIETED DOWN CONSIDERABLY
ACROSS THE REGION THIS MORNING. THE MCS THAT BROUGHT ALL THE
RAINFALL EARLIER THIS MORNING HAS WEAKENED TO JUST A FEW SHOWERS
ACROSS WESTERN AZ AND THE LOWER COLORADO RIVER VALLEY. THE MAIN
IMPACT FROM THE RAINFALL AND CLOUDINESS IS TO COOL TEMPERATURES
ACROSS MUCH OF THE REGION...WITH MANY LOCATIONS ACROSS THE LOWER
DESERTS OF WESTERN AZ AND THE LOWER COLORADO RIVER VALLEY NOW SEEING
TEMPERATURES IN THE 70S. THIS RAIN-COOLED AIR AND DEBRIS CLOUDS WILL
LIKE DELAY THE ONSET OF CONVECTIVE ACTIVITY TODAY...WITH THE LATEST
MODEL RUNS SHOWING SHOWER AND THUNDERSTORM DEVELOPMENT HOLDING OFF
UNTIL THIS EVENING AND TONIGHT. OTHER THAN SOME ADJUSTMENTS TO LOWER
TEMPERATURES ACROSS SOUTHWEST AZ AND SOUTHEAST CA...CURRENT GRIDDED
FORECAST ARE HOLING UP QUITE WELL.
&&
.PREVIOUS DISCUSSION...
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL GULF OF CALIFORNIA
THIS MORNING. EXTENDING NORTHWARD FROM THE LOW INTO CENTRAL AZ IS AN
INVERTED TROUGH AND MCV...WHICH HAVE HELPED TO SUSTAIN A NOCTURNAL
MCS ACROSS THE LOWER DESERTS OF AZ. LATEST IR IMAGERY INDICATES THAT
CLOUD TOPS HAVE COOLED TO AS LOW AS -75C...WHICH CORRELATES TO TOPS
AROUND 40-45K FT...THOUGH KIWA RADAR SUGGESTS SOME OVERSHOOTING TOPS
MAY BE AS HIGH AS 55K FT. MUCH OF PHOENIX...NORTH SCOTTSDALE AND THE
WEST VALLEY RECEIVED MEASURABLE RAINFALL OVER THE PAST 6
HOURS...WITH SOME SPOTS MEASURING ALMOST AN INCH. WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY CONTINUES AT THIS HOUR FROM MARICOPA
COUNTY WESTWARD...INCLUDING LA PAZ...YUMA AND RIVERSIDE COUNTIES. IT
IS EXPECTED THAT CONVECTION WILL CONTINUE TO DEVELOP EARLY THIS
MORNING ALONG OUTFLOW BOUNDARIES PROPAGATING INTO THE MOISTURE-RICH
ENVIRONMENT OF SW AZ AND SE CA. HEAVY RAINFALL AND MINOR FLOODING
ARE THE MAIN THREATS WITH THESE STORMS.
GLOBAL MODELS NOTORIOUSLY HAVE A DIFFICULT TIME INITIALIZING
PROPERLY WHEN THERE IS CONVECTION OVERNIGHT. FORECAST IS INSTEAD
WEIGHTED MORE TOWARDS THE HI-RES CONVECTIVE ALLOWING MODELS SUCH AS
THE WRF-NMM FOR SPC...WHICH HAS PICKED UP ON THE CURRENT ACTIVITY.
ALTHOUGH THE EASTERLY FLOW BETWEEN THE LOW TO THE SOUTH AND THE
ANTICYCLONE ACROSS NV WILL DIMINISH TODAY...SOUTH-CENTRAL AZ IS
AGAIN FAVORED FOR NOCTURNAL CONVECTION. CONDITIONS REMAIN SO
ANOMALOUSLY MOIST THAT MODELS SUCH AS THE HRRR SUGGEST THAT
CONVECTION MAY INITIATE AS EARLY AS THIS AFTERNOON. TEMPERATURES
WILL ALSO BE CONSIDERABLY LOWER TODAY...WITH HIGH TEMPERATURES
STRUGGLING TO REACH THE 100 DEGREE MARK IN THE LOWER DESERTS.
THE UPPER LOW ACROSS THE GOC IS EXPECTED TO LIFT NORTHWARD TO A
POSITION JUST WEST OF ROCKY POINT SUNDAY. THE THREAT OF SHOWERS AND
THUNDERSTORMS WILL PERSIST JUST ABOUT EVERYWHERE ACROSS THE FORECAST
AREA. POPS IN THE 12Z-18Z PERIOD SUNDAY WERE INCREASED...OWING TO
MUCH HIGHER PROBABILITIES FROM THE NMM-BASED GUIDANCE SUCH AS THE
SREF. WITH THE AMPLE MOISTURE AND SUBSEQUENT CLOUDINESS...AN
ADDITIONAL 3 TO 5 DEGREES OF COOLING IS ALSO ANTICIPATED.
EARLY NEXT WEEK...THE UPPER LOW WILL GET PICKED UP BY THE WESTERLIES
AS THE ANTICYCLONE SLIDES TOWARDS THE FOUR CORNERS. THE RESULTING
SOUTHWESTERLY FLOW WILL ADVECT DRIER AIR INITIALLY INTO SE CA AND SW
AZ...WHICH WILL CONFINE THE HIGHEST POPS TO HIGHER TERRAIN NORTH AND
EAST OF PHOENIX. THE RIDGE WILL BECOME REESTABLISHED ACROSS THE
SOUTHERN PLAINS THURSDAY...WHICH WILL ALLOW ANOTHER MOIST INVERTED
TROUGH TO APPROACH SOUTHERN AZ. CONSEQUENTLY...A RETURN TO NEAR
CLIMO POPS/TEMPS IS FORECAST FOR THE END OF THE WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
NEW STORMS CONTINUE TO DEVELOP OVER HIGHER TERRAIN EAST OF GLOBE.
ALTHOUGH SLOW TO MOVE WEST...MAY SEE EASTERLY OUTFLOW FROM THESE
STORMS AFFECTING KIWA LATER AFTER 11Z. OUTSIDE OF THIS ACTIVITY...
LIGHT WINDS AND SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT ARE EXPECTED
ACROSS THE SOUTH-CENTRAL AZ DESERTS THIS MORNING. BY 20Z...STORMS
WILL AGAIN FORM OVER THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER SOUTHEAST
CALIFORNIA THIS MORNING THROUGH AT LEAST 13Z...WITH GUSTY OUTFLOWS
UP TO 30KT POSSIBLE AT TIMES. SCT-BKN CLOUD DECKS GENERALLY AOA
10KFT WITH LOCAL CIGS DOWN TO 8KFT IN HEAVIER SHOWERS AND
THUNDERSTORMS...SKIES IMPROVING LATER THIS MORNING. WINDS SOUTHERLY
10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE LOWER COLORADO
RIVER VALLEY WITH LIGHTER SOUTHEASTERLY WINDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
ABOVE NORMAL PRECIP CHANCES WILL REMAIN A POSSIBILITY ON MONDAY AS A
AN AREA OF LOW PRESSURE EXISTS THE AREA. A SWITCH TO A SOUTHERLY
FLOW ALOFT WILL LIKELY BRING DRYING CONDITIONS AND ENDING
PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA FOR THE MIDDLE OF NEXT WEEK. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY. STORM
COVERAGE AND INTENSITY WILL VARY FROM DAY TO DAY WHICH WILL IMPACT
FORECAST WINDS...POTENTIALLY DISRUPTING NORMAL DIURNAL PATTERNS.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/HIRSCH
AVIATION...MEYERS
FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
330 AM MST SAT JUL 20 2013
.SYNOPSIS...
A VERY MOIST AIRMASS IS EXPECTED TO REMAIN OVER THE REGION AS A LOW
PRESSURE SYSTEM IN MEXICO MOVES OFF WELL TO SOUTH AND WEST. ABOVE
NORMAL RAIN CHANCES AND BELOW NORMAL TEMPERATURES ARE EXPECTED
THROUGH MONDAY. SOMEWHAT DRIER AND WARMER WEATHER IS EXPECTED FROM
TUESDAY ONWARD THROUGH THE END OF NEXT WEEK AS HIGH PRESSURE BECOMES
REESTABLISHED ACROSS THE ROCKIES.
&&
.DISCUSSION...
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL GULF OF CALIFORNIA
THIS MORNING. EXTENDING NORTHWARD FROM THE LOW INTO CENTRAL AZ IS AN
INVERTED TROUGH AND MCV...WHICH HAVE HELPED TO SUSTAIN A NOCTURNAL
MCS ACROSS THE LOWER DESERTS OF AZ. LATEST IR IMAGERY INDICATES THAT
CLOUD TOPS HAVE COOLED TO AS LOW AS -75C...WHICH CORRELATES TO TOPS
AROUND 40-45K FT...THOUGH KIWA RADAR SUGGESTS SOME OVERSHOOTING TOPS
MAY BE AS HIGH AS 55K FT. MUCH OF PHOENIX...NORTH SCOTTSDALE AND THE
WEST VALLEY RECEIVED MEASURABLE RAINFALL OVER THE PAST 6
HOURS...WITH SOME SPOTS MEASURING ALMOST AN INCH. WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY CONTINUES AT THIS HOUR FROM MARICOPA
COUNTY WESTWARD...INCLUDING LA PAZ...YUMA AND RIVERSIDE COUNTIES. IT
IS EXPECTED THAT CONVECTION WILL CONTINUE TO DEVELOP EARLY THIS
MORNING ALONG OUTFLOW BOUNDARIES PROPAGATING INTO THE MOISTURE-RICH
ENVIRONMENT OF SW AZ AND SE CA. HEAVY RAINFALL AND MINOR FLOODING
ARE THE MAIN THREATS WITH THESE STORMS.
GLOBAL MODELS NOTORIOUSLY HAVE A DIFFICULT TIME INITIALIZING
PROPERLY WHEN THERE IS CONVECTION OVERNIGHT. FORECAST IS INSTEAD
WEIGHTED MORE TOWARDS THE HI-RES CONVECTIVE ALLOWING MODELS SUCH AS
THE WRF-NMM FOR SPC...WHICH HAS PICKED UP ON THE CURRENT ACTIVITY.
ALTHOUGH THE EASTERLY FLOW BETWEEN THE LOW TO THE SOUTH AND THE
ANTICYCLONE ACROSS NV WILL DIMINISH TODAY...SOUTH-CENTRAL AZ IS AGAIN
FAVORED FOR NOCTURNAL CONVECTION. CONDITIONS REMAIN SO ANOMALOUSLY
MOIST THAT MODELS SUCH AS THE HRRR SUGGEST THAT CONVECTION MAY
INITIATE AS EARLY AS THIS AFTERNOON. TEMPERATURES WILL ALSO BE
CONSIDERABLY LOWER TODAY...WITH HIGH TEMPERATURES STRUGGLING TO
REACH THE 100 DEGREE MARK IN THE LOWER DESERTS.
THE UPPER LOW ACROSS THE GOC IS EXPECTED TO LIFT NORTHWARD TO A
POSITION JUST WEST OF ROCKY POINT SUNDAY. THE THREAT OF SHOWERS AND
THUNDERSTORMS WILL PERSIST JUST ABOUT EVERYWHERE ACROSS THE FORECAST
AREA. POPS IN THE 12Z-18Z PERIOD SUNDAY WERE INCREASED...OWING TO
MUCH HIGHER PROBABILITIES FROM THE NMM-BASED GUIDANCE SUCH AS THE
SREF. WITH THE AMPLE MOISTURE AND SUBSEQUENT CLOUDINESS...AN
ADDITIONAL 3 TO 5 DEGREES OF COOLING IS ALSO ANTICIPATED.
EARLY NEXT WEEK...THE UPPER LOW WILL GET PICKED UP BY THE WESTERLIES
AS THE ANTICYCLONE SLIDES TOWARDS THE FOUR CORNERS. THE RESULTING
SOUTHWESTERLY FLOW WILL ADVECT DRIER AIR INITIALLY INTO SE CA AND SW
AZ...WHICH WILL CONFINE THE HIGHEST POPS TO HIGHER TERRAIN NORTH AND
EAST OF PHOENIX. THE RIDGE WILL BECOME REESTABLISHED ACROSS THE
SOUTHERN PLAINS THURSDAY...WHICH WILL ALLOW ANOTHER MOIST INVERTED
TROUGH TO APPROACH SOUTHERN AZ. CONSEQUENTLY...A RETURN TO NEAR CLIMO
POPS/TEMPS IS FORECAST FOR THE END OF THE WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
NEW STORMS CONTINUE TO DEVELOP OVER HIGHER TERRAIN EAST OF GLOBE.
ALTHOUGH SLOW TO MOVE WEST...MAY SEE EASTERLY OUTFLOW FROM THESE
STORMS AFFECTING KIWA LATER AFTER 11Z. OUTSIDE OF THIS ACTIVITY...
LIGHT WINDS AND SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT ARE EXPECTED
ACROSS THE SOUTH-CENTRAL AZ DESERTS THIS MORNING. BY 20Z...STORMS
WILL AGAIN FORM OVER THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER SOUTHEAST
CALIFORNIA THIS MORNING THROUGH AT LEAST 13Z...WITH GUSTY OUTFLOWS
UP TO 30KT POSSIBLE AT TIMES. SCT-BKN CLOUD DECKS GENERALLY AOA
10KFT WITH LOCAL CIGS DOWN TO 8KFT IN HEAVIER SHOWERS AND
THUNDERSTORMS...SKIES IMPROVING LATER THIS MORNING. WINDS SOUTHERLY
10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE LOWER COLORADO
RIVER VALLEY WITH LIGHTER SOUTHEASTERLY WINDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
ABOVE NORMAL PRECIP CHANCES WILL REMAIN A POSSIBILITY ON MONDAY AS A
AN AREA OF LOW PRESSURE EXISTS THE AREA. A SWITCH TO A SOUTHERLY
FLOW ALOFT WILL LIKELY BRING DRYING CONDITIONS AND ENDING
PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA FOR THE MIDDLE OF NEXT WEEK. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY. STORM
COVERAGE AND INTENSITY WILL VARY FROM DAY TO DAY WHICH WILL IMPACT
FORECAST WINDS...POTENTIALLY DISRUPTING NORMAL DIURNAL PATTERNS.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...MEYERS
FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
905 PM MST FRI JUL 19 2013
.SYNOPSIS...LOW PRESSURE OVER THE GULF OF CALIFORNIA WILL PROVIDE A
MOIST EAST TO SOUTHEAST FLOW THIS WEEKEND. THIS FLOW WILL INCREASE
CHANCES FOR SHOWERS AND THUNDERSTORMS WITH POTENTIALLY HEAVY
RAINFALL. THEREAFTER...A MORE NORMAL CYCLE OF SCATTERED AFTERNOON
AND EVENING THUNDERSTORMS WILL RETURN FOR MUCH OF NEXT WEEK.
&&
.DISCUSSION...ISOLATED SHOWERS ONGOING ACROSS ERN SANTA CRUZ AND
SWRN COCHISE COUNTIES SOUTH OF TUCSON AS WELL AS ACROSS NRN GREENLEE/
NRN GRAHAM COUNTIES NE OF TUCSON. DRY CONDITIONS PREVAILED ELSEWHERE
ACROSS SE AZ AT THIS TIME. CLOUD TOPS ASSOCIATED WITH THE MCS ACROSS
NERN SONORA WERE WARMING DURING THE PAST 1-2 HOURS.
THE PAST 3 HOURS OF RUC HRRR SOLUTIONS HAVE YIELDED FAIRLY MARKEDLY
DIFFERENT RESULTS REGARDING PRECIP POTENTIAL THE REST OF TONIGHT. 2
SOLUTIONS YIELDED PRECIP TO REDEVELOP AROUND MIDNIGHT JUST NORTH AND
WEST OF TUCSON AND CONTINUE TO MOVE WEST ACROSS THE TOHONO O`ODHAM
NATION. ONE SOLUTION YIELDED VERY LITTLE PRECIP THE REST OF TONIGHT.
BASED ON THE 20/00Z UPPER PLOTS...AM INCLINED TO BELIEVE THAT
ISOLATED TO PERHAPS SCATTERED SHOWERS AND A FEW THUNDERSTORMS MAY
OCCUR THRU ABOUT 20/09Z DUE TO DIFFLUENCE ALOFT. RAINFALL AMOUNTS
SHOULD BE QUITE LIGHT AS PER EACH RUC HRRR SOLUTION. THUS...NO
CHANGES OF SIGNIFICANCE FOR THE INHERITED GRIDDED DATA POP FIELDS
FOR THE REST OF TONIGHT.
MIN TEMPS LATER TONIGHT ARE FORECAST TO BE WITHIN A DEGREE-OR-TWO OF
NORMAL. PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION BELOW FOR
ADDITIONAL DETAIL.
&&
.PREV DISCUSSION /155 PM MST FRI JUL 19 2013/...WITH THE LOW
PRESSURE OVER SONORA AND ATTENDANT CLOUDS DRIFTING ONLY SLOWLY WEST
THEN UP THE BAJA/GULF AREA THE NEXT FEW DAYS...MORNING CLOUDS COULD
CONTINUE TO HINDER ATMOSPHERIC HEATING...BUT IF THIS HINDRANCE IS
OVERCOME...STORMS THAT DEVELOP COULD PRODUCE HEAVY RAIN. MODEL
DEPICTIONS OF THE LOW TRACK AND THE MOISTURE FIELDS TEND TO FAVOR
MUCH OF THE AREA STILL BEING AFFECTED BY CLOUD COVER AND ONCE AGAIN
LIMITING HEATING...WHEREAS SUNDAY WE MAY WARM UP QUICKER AND BE ABLE
TO GENERATE MORE THUNDERSTORM COVERAGE.
FOR NEXT WEEK...A SECONDARY AREA OF LOW PRESSURE WILL MOVE ACROSS
NRN MEXICO...POSSIBLY INFLUENCING OUR WEATHER ONCE AGAIN AND KEEPING
THE CHANCES FOR THUNDERSTORMS AT OR ABOVE CLIMATOLOGICAL NORMALS...KD
&&
.AVIATION...SCATTERED -SHRA AND ISOLATED -TSRA MOSTLY ENDING AROUND
20/09Z. SCATTERED TO NUMEROUS SHRA/TSRA TO OCCUR SATURDAY AFTERNOON
AND CONTINUE INTO SATURDAY EVENING. MVFR CONDITIONS WITH BRIEF WIND
GUSTS TO AROUND 45 KTS WITH THE STRONGER TSRA. OTHERWISE...CLOUD
DECKS GENERALLY 5-9K FT AGL AND SURFACE WIND MAINLY LESS THAN 10 KTS
THRU SATURDAY EVENING OR 21/06Z. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...UPPER LOW OVER SONORA MEXICO WILL MAINTAIN A MOIST
EASTERLY FLOW ACROSS SOUTHERN ARIZONA THROUGH THE WEEKEND. THE
COMBINATION OF THE UPPER LOW AND ABUNDANT ATMOSPHERIC MOISTURE WILL
BRING ABOUT PLENTY OF CONVECTION THAT WILL BE ABLE TO OCCUR ANYTIME
WITH A FOCUS DURING THE AFTERNOON AND EVENING HOURS. THE STRONGER
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING HEAVY DOWNPOURS AS WELL
AS GUSTY AND ERRATIC WINDS. RELATIVE HUMIDITIES WILL REMAIN MOIST
WITH THE NORMAL DIURNAL WIND PATTERNS DISRUPTED AT TIMES THIS
WEEKEND BY CONVECTION. THE SHOWERS AND THUNDERSTORMS WILL BECOME
LESS NUMEROUS AND MORE DIURNAL IN NATURE NEXT WEEK AS THE LOW MOVES
FURTHER WEST AND THE AIR MASS BECOMES A BIT DRIER.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION/AVIATION...FRANCIS
PREVIOUS DISCUSSION...DROZD
FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
255 AM PDT SAT JUL 20 2013
.SYNOPSIS...
A MOIST EAST FLOW PATTERN WILL BRING INCREASING MONSOONAL MOISTURE
WITH PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS THROUGH
MONDAY...DECREASING ON TUESDAY. FLASH FLOODING IS POSSIBLE IN RECENT
BURN AREAS. WARMER AND DRIER FOR THE LATTER HALF OF NEXT WEEK WITH
SOUTHWEST FLOW ALOFT.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (TODAY THROUGH MONDAY)...
IN THE NEAR TERM...THE MESOSCALE CONVECTIVE SYSTEM OVER SAN
BERNARDINO COUNTY WILL CONTINUE TO MOVE WESTWARD AND SLOWLY WEAKEN
BASED ON SATELLITE AND RADAR TRENDS. MODELS HAVE TYPICALLY BEEN OF
LIMITED VALUE IN HANDLING THIS SYSTEM WITH THE 02Z HRRR THE LEAST
CLUELESS OF THE BUNCH. IT AT LEAST SHOWED A CIRCULATION CENTER AND
MOSTLY ASSOCIATED SHOWERS TRANSLATING WESTWARD ACROSS SOUTHERN
CALIFORNIA THIS MORNING. THE MODELS HAVE ALSO BEEN LESS THAN HELPFUL
WITH REGARD TO THE MORE RECENT CONVECTION IN SOUTHWEST ARIZONA AND
THE FAR EASTERN DESERTS OF SOUTHERN CALIFORNIA. THAT CONVECTION
CONTINUES TO MOVE SLOWLY WESTWARD AND COULD AT LEAST PUSH SOME
OUTFLOW ACROSS THE LOWER DESERTS OF SOUTHERN CALIFORNIA.
HIGH PRESSURE OVER NEVADA WILL DIRECT AN INCREASINGLY MOIST
MONSOONAL AIR MASS INTO SOUTHWEST CALIFORNIA THROUGH SUNDAY.
PRECIPITABLE WATER VALUES A LITTLE OVER ONE INCH FRIDAY AFTERNOON
WILL INCREASE TO 1.4 INCHES THIS AFTERNOON AND 1.7 INCHES SUNDAY
AFTERNOON. A DRYING TREND WILL BEGIN MONDAY. THIS WILL BRING PERIODS
OF SHOWERS AND ISOLATED THUNDERSTORMS INTO MONDAY. SOME
PRECIPITATION COULD MOVE WEST OF THE MOUNTAINS TONIGHT THROUGH
SUNDAY NIGHT. THE ABUNDANT MID AND HIGH LEVEL MOISTURE WILL LIMIT
SURFACE HEATING AND THE POTENTIAL FOR STRONGER AFTERNOON
THUNDERSTORMS SOMEWHAT THROUGH SUNDAY. HOWEVER...GIVEN THE
INCREASING MOISTURE CONTENT...THUNDERSTORMS THAT DO DEVELOP COULD
PRODUCE LOCALLY HEAVY RAINFALL. FLASH FLOOD GUIDANCE THRESHOLDS FOR
NEW BURN AREAS ARE THREE TENTHS OF AN INCH OF RAINFALL IN 30
MINUTES...SOMETHING THAT WOULD BE POSSIBLE WITH ANY OF THE
THUNDERSTORMS. HENCE...A FLASH FLOOD WATCH FOR THE BURN AREAS HAS
BEEN ISSUED THROUGH SUNDAY EVENING.
AS THE HIGHER LEVEL MOISTURE BEGINS TO DECREASE MONDAY WITH THE MID
LEVEL MOISTURE REMAINING IN PLACE...THERE WOULD BE GREATER POTENTIAL
FOR DEVELOPMENT OF STRONGER THUNDERSTORMS MONDAY AFTERNOON WITH
GREATER POTENTIAL FOR FLASH FLOODING IN THE MOUNTAINS AND
DESERTS...NOT JUST IN RECENT BURN AREAS.
THE INCREASING CLOUD COVER WILL BRING COOLING FOR INLAND AREAS INTO
SUNDAY WITH SLOW WARMING FOR MONDAY. THE MARINE LAYER AND ONSHORE
LOWER LEVEL FLOW WILL CONTINUE TO KEEP COASTAL AREAS COOLER WITH
AREAS OF NIGHT AND MORNING LOW CLOUDS AND FOG.
&&
.LONG TERM (TUESDAY THROUGH FRIDAY)...
A WEAK TROUGH OF LOW PRESSURE NEAR THE WEST COAST SHOULD BRING A
DRYING TREND FOR THE MIDDLE TO LATTER PART OF THE WEEK. THERE MAY
STILL BE ENOUGH RESIDUAL MOISTURE FOR AFTERNOON THUNDERSTORMS OVER
THE MOUNTAINS TUESDAY. AS THE MOISTURE DECREASES...INLAND AREAS WILL
WARM.
&&
.AVIATION...
200930Z...COAST/VALLEYS...STRATUS WITH BASES 1200-1500 FT MSL HAS
MOVED 15-20SM. LOW CLOUDS EXPECTED TO CLEAR IN THE VALLEYS 15-17Z
AND ALONG THE COAST 18-20Z...WITH SOME CLOUDS CLINGING TO THE
BEACHES THROUGH THE AFTERNOON. STRATUS RETURNING TO COASTAL AIRPORTS
01-03Z WITH SIMILAR BASES AND TOPS. OTHERWISE...SCT-BKN CLOUDS AOA
8000 FT MSL AND AREAS OF SMOKE FROM THE MOUNTAIN FIRE...ESPECIALLY
IN THE SOUTHERN INLAND EMPIRE. A SLIGHT CHANCE OF LIGHT SHOWERS AND
THUNDERSTORMS BEGINNING SAT AFTERNOON. ANY TSTMS THAT DEVELOP WILL
LIKELY PRODUCE LITTLE RAIN AND GUSTY SFC WINDS.
MTNS/DESERTS...SCT-BKN CLOUDS AOA 8000 FT MSL. EASTERLY WINDS MAY
INCREASE EARLY THIS MORNING FOR A SHORT TIME OVER THE LOW DESERTS AS
OUTFLOW FROM THUNDERSTORMS MOVES THROUGH. OTHERWISE...A CHANCE OF
SHOWERS AND THUNDERSTORMS BEGINNING SAT AFTERNOON...WITH THE BEST
CHANCES OVER THE MTN RIDGES. BASES WILL BE NEAR 8-10K FT WITH TOPS
TO 40K FT.
&&
.MARINE...
LONG PERIOD SOUTH-SOUTHWEST SWELL CURRENTLY PEAKING WITH A
REINFORCING 3-4 FT/16-17 SEC PERIOD SWELL ARRIVING LATER TODAY. THIS
WILL CONTINUE ELEVATED SURF AND STRONG RIP CURRENTS ALONG SOUTH AND
SOUTHWEST FACING BEACHES THROUGH THE WEEKEND WITH LOCAL SURF SETS
AROUND 7 FEET POSSIBLE...MAINLY IN ORANGE COUNTY. HIGH TIDES WILL BE
ABOVE 7 FEET EACH EVENING SAT THROUGH MON. THE COMBINATION OF
ELEVATED SURF AND HIGH TIDES MAY PRODUCE MINOR COASTAL FLOODING
ALONG VULNERABLE LOW-LYING AREAS. A BEACH HAZARDS STATEMENT
CONTINUES THROUGH SUN EVENING. SURF AND SWELL WILL DIMINISH EARLY
NEXT WEEK.
&&
.FIRE WEATHER...
A MOIST EAST FLOW PATTERN WILL BRING INCREASING MONSOONAL MOISTURE
WITH PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS WITH WETTING
RAINS THROUGH MONDAY...DECREASING ON TUESDAY. THUNDERSTORM WIND
GUSTS TO 40 MPH ARE POSSIBLE WITH FLASH FLOODING POSSIBLE IN RECENT
BURN AREAS. WARMER AND DRIER FOR THE LATTER HALF OF NEXT WEEK WITH
SOUTHWEST FLOW ALOFT.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR BURN AREAS OF THE
RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY DESERTS...SAN
DIEGO COUNTY MOUNTAINS.
BEACH HAZARDS STATEMENT THROUGH SUNDAY EVENING FOR THE BEACHES
IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY
COASTAL AREAS.
PZ...NONE.
&&
$$
PUBLIC...17
AVIATION/MARINE...TS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
856 PM MDT SUN JUL 21 2013
.UPDATE...
&&
.SHORT TERM...CWA IS MOSTLY STORM FREE EXCEPT FOR A FEW SHOWERS
REMAINING ACROSS PARK COUNTY. THE EARLIER ACTIVITY ACROSS LINCOLN
AND WASHINGTON COUNTIES HAVE LONG SINCE ENDED. WILL STILL KEEP
ISOLATED POPS OVER THE FAR NORTHEAST CORNER IN CASE THE CONVECTION
OVER NEBRASKA AND EASTERN WYOMING MAKES IT FARTHER SOUTH INTO
COLORADO LATER TONIGHT.
.AVIATION...SURFACE BOUNDARY PUSHING NORTHWARD OVER DOUGLAS AND
ELBERT COUNTIES WILL SHIFT WINDS MORE S-SW OVER TERMINALS DURING
THE NEXT HOUR. OTHERWISE MOSTLY CLEAR SKIES TONIGHT. &&
.PREV DISCUSSION... /ISSUED 257 PM MDT SUN JUL 21 2013/
SHORT TERM...STRONG OUTFLOW FROM T-STORMS UP IN NEBRASKA LAST
NIGHT...BACKED ACROSS NORTHEAST COLORADO EARLIER TODAY. THIS
SHALLOW MOIST AIRMASS SIGNIFICANTLY INFLUENCED TEMPERATURES EAST
OF THE MOUNTAINS TODAY. CURRENT TEMPERATURES ARE RUNNING SEVERAL
DEGS BEHIND THOSE YESTERDAY AT THIS TIME...THEREBY CREATING A
STRONG CAP UP AROUND 750 MBS NEAR THE FOOTHILLS...AND UP AROUND
700 MBS FARTHER OUT OVER THE PLAINS ACCORDING RUC SOUNDINGS AND
CROSS SECTIONS. BENEATH THIS PSUEDO-FRONTAL INVERSION...BNDRY
LAYER CAPE VALUES ARE NOW NEAR 700 J/KG UP AGAINST THE FOOTHILLS
AND CLOSE TO 1500 J/KG IN THE FAR NORTHEAST. DO SEE THIS ENERGY
BEING TAPPED NEAR THE FOOTHILLS EVEN WITH ISOLATED LOW TOP
CONVECTION DRIFTING OFF THE FOOTHILLS WITH ALL OF THE CIN IN THIS
AREA. FARTHER OUT ON THE PLAINS...COULD SEE THE WEAK SHORTWAVE
DISTURBANCE NOW SWINGING OVER SERN WYOMING TAPPING INTO SOME OF
THIS PENNED UP ENERGY RESULTING IN A FEW T-STORMS IN THE FAR
NORTHEAST COUNTIES AFTER 5 PM MDT TODAY. MORE LIKELY WE/LL SEE
THIS CONVECTION DURING THE EVENING HOURS WITH THE LAST OF THE
CIN ERRODING AS THE SHORTWAVE PASSES BY. NOT LOOKING FOR ANY
SEVERE WX OUT OF THEM...JUST PERHAPS SOME SMALL HAIL...BRIEF HEAVY
RAIN AND GUSTY OUTFLOW WINDS TO AROUND 50 MPH. STORMS SHOULD END
EARLIER TONIGHT WITH ARRIVAL OF DRIER AND MORE STABLE AIR BEHIND
THIS SHORTWAVE. HOWEVER...LINGERING LOW LEVEL MOISTURE MAY AGAIN
RESULT IN AREAS OF LOW CLOUDS AND/OR PATCHY FOG IN THE FAR
NORTHEAST TOWARDS MORNING.
ON MONDAY...AIRMASS APPEARS MUCH DRIER AND WARMER. WITH THE UPPER
RIDGE STRENGTHENING TO OUR WEST..AND BARRING ANY UNFORESEEN MOIST
OUTFLOW FROM DOWNSTREAM STORMS...SHOULD SEE TEMPERATURES EASILY
CLIMBING INTO THE 90S ON THE PLAINS TOMORROW...WITH 70S AND 80S IN
THE MTNS. IT/S NOT OUT THE QUESTION WE COULD SEE LOW 90S POPPING
UP IN A FEW SPOTS ALONG THE UPPER COLORADO IN GRAND COUNTY.
DO NOT ANTICIPATE ANY PRECIPITATION/T-STORMS ON MONDAY.
LONG TERM...OVERALL NO BIG CHANGES TO THE ONGOING TRENDS IN THE
FORECAST. THE UPPER LEVEL RIDGE WILL BE CENTERED NEAR THE GREAT
BASIN FOR MONDAY NIGHT INTO TUESDAY. AS A RESULT...A DRY AND
STABLE NORTHWESTERLY FLOW ALOFT WILL BE OVER THE CWFA. PLENTY OF
LOW LEVEL MOISTURE OVER THE NORTHEAST PLAINS...BUT TOO SUBSIDENT
IN THE MID LEVELS TO ALLOW THE INITIATION OF DEEP CONVECTION FOR
MOST OF THE FORECAST AREA. A WEAK SYSTEM PASSING ACROSS THE NRN
GREAT PLAINS AND INTO THE MID WEST COULD BE ENOUGH TO INITIATE
TSTMS OVER THE FAR NERN CORNER OF CO LATE TUESDAY. FOR THE REST OF
THE WEEK...THE CENTER OF RIDGE SHIFTS EASTWARD WHICH OPENS UP
WESTERN CO TO SUBTROPICAL MID MOISTURE FM THE SOUTH. BETTER TSTM
COVERAGE SHOULD HELP TO SHAVE A FEW DEGREES OF THE AFTN
TEMPERATURES AS WELL. THE ECMWF AND GFS BOTH SHOW BOTH DEVELOP
DECENT QPF OVER THE AREA LATE WEDNESDAY AND THURSDAY...WITH A BIT
OF DRYING ON FRIDAY. MDLS DIFFER AS TO HOW MUCH MOISTURE WILL BE
AVAILABLE OVER THE WEEKEND SO SLGT CHC SHOULD SUFFICE FOR NOW.
AVIATION...VFR CONDITIONS ANTICIPATED FOR THE NEXT 24 HOURS
UNDER NORTHWEST FLOW ALOFT. NORTH-NORTHEAST SURFACE WINDS UNDER
12 KTS AT MOST DENVER AREA AIRPORTS SHOULD GRADUALLY BECOME
EASTERLY AT SIMILAR SPEEDS AFTER 23Z AND LINGER THROUGH EARLY
EVENING...THEN GO TO A DRAINAGE WIND OVERNIGHT. DIA AND APA COULD
SEE GUSTY SOUTHERLY WINDS OF 10-20 KTS DEVELOPING IN THE EVENING
WITH THE FORMATION A TIGHT PRES GRADIENT JUST EAST OF THE METRO
AREA. AFTER SAY 08Z...SHOULD SEE WIND SPEEDS RELAX AND RESUME
MORE TYPICAL SPEEDS UNDER 12KS. ON MONDAY SOUTHERLY WINDS UNDER
12KS ARE FORECAST TO GO WEST-NORTHWEST BY LATE MORNING AT SIMILAR
SPEEDS. WITH FEW CLOUDS AROUND...SHOULD SEE DAYTIME TEMPERATURES
RETURNING TO THE 90S.
HYDROLOGY...NO CONCERNS AT THIS TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
307 PM MDT SAT JUL 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM MDT SAT JUL 20 2013
THE HIGHER LEVEL MSTR PLUME HAS SHIFTED SOUTH OF THE AREA
TODAY...BUT LOW LEVEL MSTR REMAINS IN PLACE WITH DEW POINTS MOSTLY
IN THE 50S OVR THE SERN PLAINS AND AROUND 50 IN THE SAN LUIS
VALLEY. EXPECTING MOST OF THE CONVECTIVE ACTIVITY THIS EVENING TO
BE OVR AND NR THE MTS. SO FAR TODAY...THE SHOWERS THAT HAVE
DEVELOPED WERE MOVING AROUND 10-12 MPH TO THE SE OR SSE. THIS SLOW
MOVEMENT WL AGAIN LEAD TO THE CONCERN FOR LOCALLY HEAVY RAIN ON THE
BURN SCARS AND THE POTENTIAL FOR FLASH FLOODING IF A HEAVIER STORM
MOVES OVR OR DEVELOPS ON A BURN SCAR. THE NAM AND HRRR MOVE SOME
STORMS OFF THE MTS AND ACRS THE I-25 CORRIDOR...MAINLY OVR EL PASO
AND NRN PUEBLO COUNTIES THIS EVENING. A SHORTWAVE TROF MOVING ACRS
NERN AND EAST CENTRAL CO TONIGHT IS EXPECTED TO BRING SOME
CONVECTIVE ACTIVITY TO THOSE AREAS...BUT AT THIS TIME THE HI RES
MODELS ARE KEEPING THAT MAINLY NORTH OF THE CWA...BUT COULD SEE SOME
SHOWERS/TSTMS IN KIOWA COUNTY ASSOC WITH THE DISTURBANCE. WE COULD
SEE A FEW LINGERING SHOWERS OVR THE MTS UNTIL MIDNIGHT OR A LITTLE
LATER...BUT THEN BY MORNING ALL AREAS SHOULD BE DRY.
ON SUN IT LOOKS LIKE SOME ISOLD TO SCT SHOWER/TSTMS COULD DEVELOP
OVR THE HYR TRRN AROUND NOON...WITH THE BEST CHANCES BEING OVR THE
SW MTS AND THE SRN SANGRES. A WEAK DISTURBANCE IS EXPECTED TO MOVE
ACRS NERN CO IN THE AFTERNOON...AND THE NAM HAS SOME CONVECTIVE
ACTIVITY FIRING UP IN NORTHEAST AND EAST CENTRAL CO...INCLUDING
KIOWA AND CROWLEY COUNTIES BY EVENING. THE GFS KEEPS THE CONVECTION
OVR NERN CO. FOR NOW WL GO WITH A DRY FORECAST FOR THE FAR SERN
PLAINS SUN AFTERNOON. HIGH TEMPS ON SUN LOOK A COUPLE OR FEW DEGREES
WARMER THAN TODAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 230 PM MDT SAT JUL 20 2013
HOT AND MAINLY DRY CONDITIONS EXPECTED MON AND TUESDAY AS UPPER
RIDGE RE-AMPLIFIES OVER THE WESTERN US. MOISTURE PLUME WILL REMAIN
SUPPRESSED TO THE SOUTH BOTH DAYS...THOUGH PERHAPS JUST ENOUGH
RESIDUAL LOW LEVEL MOISTURE WILL LINGER TO PRODUCE AN ISOLATED
HIGH BASED TSRA OVER THE MOUNTAINS...ESPECIALLY MON. WITH HEIGHTS
RISING AND 700 MB TEMPS CLIMBING TOWARD 20C...EXPECT MAX TEMPS
MON/TUE WILL REACH 100F PLUS OVER THE LOWER ARKANSAS VALLEY...WITH
80S/90S ELSEWHERE. FRONT DROPS THROUGH THE EASTERN PLAINS LATE TUE
NIGHT/EARLY WED...LEADING TO A RENEWED WESTWARD PUSH OF MOISTURE
BY WED AFTERNOON. ECMWF HAS TRENDED TOWARD THE GFS ON WED...AND
BOTH MODELS NOW SUGGEST INCREASED CHANCES FOR TSRA OVER THE
EASTERN MOUNTAINS AND PLAINS WED AFTERNOON/EVENING. WESTERN
MOUNTAINS AND VALLEYS SHOULD ALSO SEE AN UPSWING IN TSRA WED...AS
WEAK PUSH OF MID LEVEL MOISTURE WORKS NORTHWARD UNDERNEATH THE
UPPER RIDGE AXIS. FOR LATE WEEK INTO THE WEEKEND...STILL APPEARS
AN INCREASE IN CONVECTION IS POSSIBLE MANY AREAS THU-SAT...THOUGH
DIFFERENCES BETWEEN THE EUROPEAN AND GFS ARISE BEGINNING THU...AS
EURO BRINGS A STRONG TROUGH THROUGH THE AREA...WHILE GFS IS
WEAKER/SLOWER. GFS IS THUS RATHER DRY THU...THEN MOISTENS THE AREA
FRI/SAT...WHILE FASTER ECMWF IS WETTER THU/FRI BEFORE DRYING
SLIGHTLY ON SAT. HAVE FOLLOWED THE MORE CONSISTENT GFS AT THIS
POINT...BUT MAIN MESSAGE OF BOTH MODELS IS A RETURN OF FAIRLY
WIDESPREAD CONVECTION BY WEEK`S END.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 230 PM MDT SAT JUL 20 2013
SHOWERS AND THUNDERSTORMS COULD OCCUR AT OR IN THE VCNTY OF
KCOS...KALS AND KPUB MAINLY BEFORE 02Z-03Z. IT IS POSSIBLE THAT SOME
HEAVY RAIN COULD AFFECT THE TERMINAL SITES WITH BRIEF MVFR OR IFR
CONDITIONS. OTHERWISE VFR CONDITIONS ARE EXPECTED.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1125 PM MDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 730 PM MDT FRI JUL 19 2013
UPDATED TO CANCEL FLASH FLOOD WATCH FOR EL PASO AND TELLER
COUNTIES. LATEST HIGHER RESOLUTION MODEL RUNS OF THE HRRR AND RAP
ARE NOT INDICATING AS MUCH UPSTREAM DEVELOPMENT AS PREVIOUS RUNS.
THIS IS SUPPORTED BY CURRENT RADARS INDICATING A ONLY FEW STORMS
IN PARK COUNTY WEST OF TARRYALL RESERVOIR...AS WELL AS A FEW MORE
STORMS ACROSS THE NORTHERN MTS OF SUMMIT...GRAND AND LARIMAR
COUNTIES AT THIS TIME. RADAR AND MODEL TRENDS HAVE THIS STORMS
MOVING SOUTH AND WEAKENING THROUGH THE REST OF THE EVENING...WITH
THE THREAT OF FLASH FLOODING DIMINISHING AS WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
AN UPR RIDGE WL REMAIN CENTERED OVR NV TONIGHT AND SATURDAY. A UPR
DISTURBANCE WL CONTINUE MOVING SOUTH ACRS THE FORECAST AREA
TONIGHT. THERE IS PLENTY OF MOISTURE OVER THE AREA AS WELL. ALL
THE INGREDIENTS SEEM TO BE IN PLACE TO BRING WIDESPREAD PCPN OVR AND
NR THE MTS...WITH SCT ACTIVITY OVR THE SERN PLAINS. THE STEERING
FLOW WL REMAIN FAIRLY LIGHT...RESULTING AND SLOW MOVING STORMS AND
THUS UNDER THE HEAVIER STORMS...LOCALLY HEAVY RAIN COULD FALL. THIS
BECOMES A BIG CONCERN IF IT OCCURS OVR THE BURNS SCARS AS MUD AND
ASH FLOWS COULD OCCUR. WL LEAVE THE FLASH FLOOD WATCH IN EFFECT FOR
EL PASO AND TELLER COUNTIES. AS THE UPR DISTURBANCE MOVES SOUTHWARD
OVR THE AREA...BOTH THE RAP13 AND NAM SHOW THE FOCUS OF PCPN
SHIFTING SOUTHWARD THIS EVENING OVR THE SRN MTS AND SOUTH OF HIGHWAY
50. THE HRRR ALSO SHOWS WIDESPREAD PCPN AND CHANCES FOR RAIN OVR
SRN AREAS...BUT ALSO INCREASES PCPN CHANCES OVR EL PASO...TELLER
COUNTIES AND PUEBLO COUNTIES DURING THE EVENING HOURS.
OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NORTH
TO SOUTH...WITH SOME LIGHT PCPN POSSIBLY LINGERING THRU THE NIGHT
OVR FAR SOUTHERN AREAS. IT LOOKS DRIER IN THE UPR LEVELS ON SATURDAY
AS THE MSTR PLUME SHIFTS SOUTH OF THE AREA...BUT THERE WL STILL BE
PLENTY OF LOW LEVEL MSTR TO WORK WITH FOR SCT TO LIKELY POPS OVR THE
MTS AND PROBABLY ISOLD TO SCT POPS OVR THE SERN PLAINS. STORMS
SHOULD BE FAIRLY SLOW MOVING AGAIN AND WE COULD SEE SOME LOCALIZED
HEAVY RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
UPPER LEVEL FLOW TURNS SLIGHTLY MORE NORTHWESTERLY SUNDAY...WHICH
WILL TEND TO PUSH THE MOIST PLUME SOUTH OF THE STATE INTO NM AND
AZ BY AFTERNOON. MODELS SHOW WEAK FRONTAL BOUNDARY DISSIPATING
SOMEWHERE OVER THE ERN PLAINS OF CO...WITH DECREASING LOW LEVEL
MOISTURE AS UPSLOPE WINDS WEAKEN. SUSPECT TSRA WILL STAY ISOLATED
AND LIMITED TO MAINLY THE HIGHER TERRAIN SUN AFTERNOON AND
EVENING...AND WILL END QUICKLY BY LATE EVENING WITH LITTLE IN THE
WAY OF UPPER SUPPORT. MAX TEMPS SUN SHOULD CREEP UPWARD A DEGF OR
TWO...THOUGH 700 MB TEMPS SUGGEST RATHER HOT MET GUIDANCE MAXES
MAY BE JUST A TAD TOO WARM. SIMILAR SET-UP MON/TUE...AS WEAK
SURFACE FRONT REFORMS OVER NORTHEAST COLORADO AND AIR MASS OVER
SOUTHERN COLORADO CONTINUES TO DRY. AGAIN EXPECT ISOLATED
MOUNTAIN CONVECTION BOTH DAYS...THOUGH COVERAGE AND RAINFALL
AMOUNTS WILL BE RATHER SPARSE. 700 MB TEMPS CREEP UPWARD INTO THE
18C-20C RANGE...WHICH SHOULD PRODUCE A FEW 100F PLUS READINGS OVER
THE EASTERN PLAINS BOTH DAYS. ON WED...FRONT DROPS SOUTH OVER THE
PLAINS LEADING TO A RENEWED WESTWARD SURGE OF MOISTURE OVER THE
EASTERN MOUNTAINS AND PLAINS BY AFTERNOON. GFS AND ECMWF ARE
SIMILAR WITH SURFACE FEATURES...BUT ONLY GFS BREAKS OUT CONVECTION
THU EVENING...WHILE ECMWF STAYS DRY. WILL LEAN TOWARD THE WETTER
SOLUTION OF THE GFS FOR NOW...GIVEN THE DEEPER MOISTURE AND
INSTABILITY BEHIND THE FRONT. FARTHER WEST...LOW GRADE MONSOON
REDEVELOPS WED AS SLIGHTLY DEEPER MID LEVEL MOISTURE PUSHES BACK
INTO THE STATE...LEADING TO BETTER TSRA COVERAGE THAN MON/TUE.
PAST WED...MOISTURE LOOKS TO SLOSH BACK AND FORTH ACROSS THE
EASTERN PLAINS...WITH PERHAPS A DECREASE IN PRECIP CHANCES THU AND
AN INCREASE FRI. OVER THE MOUNTAINS...UPSWING IN CONVECTION LOOKS
POSSIBLE FRI AS WELL...ESPECIALLY AS LAST FEW MODEL RUNS OF BOTH
THE ECMWF AND GFS TRY TO BUILD THE UPPER RIDGE EASTWARD INTO
TX...ALLOWING A RENEWED INFLUX OF MOISTURE FROM THE SOUTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1125 PM MDT FRI JUL 19 2013
VFR CONDITIONS EXPECTED AT TAF SITES THROUGH THE REST OF THE NIGHT
WITH MID AND HIGH LEVEL CONVECTIVE DEBRIS CLOUDS CONTINUE TO
DIMINISH. WITH THIS EVENINGS PRECIPITATION...COULD SEE SOME PATCHY
FOG DEVELOPING ACROSS THE AREA THROUGH THE EARLY MORNING HOURS WITH
BEST CHANCES AT COS AND ALS...THOUGH NOT ENOUGH CONFIDENCE TO PUT
IN TAFS AT THIS TIME. MODELS INDICATING LESS COVERAGE OF STORMS
TOMORROW AS DRIER AIR IN THE WEAK NORTHERLY FLOW ALOFT MOVES INTO
THE AREA. STILL SHOULD SEE SCATTERED STORMS ACROSS THE MTS WITH
BEST CHANCES OF STORMS AFFECTING TERMINAL BEING AT COS...THOUGH
HAVE KEPT VCTS IN PLACE AT THIS TIME.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1107 AM EDT SAT JUL 20 2013
.SYNOPSIS...
ONE MORE HOT AND HUMID DAY IS EXPECTED TODAY ALONG WITH SCATTERED
STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AS A COLD FRONT
APPROACHES FROM THE GREAT LAKES. THIS FRONT WILL BRING RELIEF FROM
THE EXCESSIVE HEAT AND HUMIDITY ON SUNDAY. MORE SEASONABLE BUT
HUMID CONDITIONS ARE EXPECTED FOR MUCH OF NEXT WEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1050 AM UPDATE...
NOTING A LOT OF SUBSIDENCE AND DRY AIR ALOFT WHICH IS TENDING TO
BREAK THE DEBRIS CLOUDS THAT HAVE MOVED ACROSS FROM NY STATE
EARLIER THIS MORNING ACROSS MOST OF THE REGION. ALSO NOTED AN AREA
OF SHOWERS THAT WORKED INTO NW MA/SW NH AROUND 14Z FROM NY STATE
TENDED TO DRY UP AS IT MOVED OUT OF THE BERKSHIRES. STARTING TO
SEE LINE OF SHOWERS/TSTMS STARTING TO DEVELOP ACROSS UPSTATE NY AS
WELL AS OVER S CENTRAL NY AT 1430Z.
HAVE UPDATED GRIDS TO SLOW DOWN THE PRECIP ESPECIALLY OVER EASTERN
AREAS UNTIL AROUND 18Z AND BEYOND. DEWPTS ARE MUCH HIGHER THAN
FORECAST...MAINLY IN THE MID 70S NEAR AND S OF THE MASS PIKE WHERE
THEY APPEAR TO BE POOLING...SO MAY BE A FOCUS OF ANY CONVECTION
THAT MAY DEVELOP PROBABLY AFTER 18Z. USED A BLEND OF OUR PREVIOUS
FORECAST WITH THE HRRR MODEL...WHICH APPEARS TO HAVE THIS SAME
FOCUS. OTHER CONVECTIVE PARAMETERS ARE MARGINAL...WITH MID LEVEL
LAPSE RATES ON ORDER OF 6C/KM...FOR LOW LEVEL LAPSE RATES ARE MUCH
HIGHER OVER CENTRAL AND EASTERN AREAS AS SEEN ON SPC MESO
ANALYSIS. SPC DID UPDATE THEIR CONVECTIVE OUTLOOK TO SHIFT IT A
BIT FURTHER S.
TEMPS ALSO A BIT HIGHER THAN FORECAST...WITH 92 AT 14Z AT KBOS.
HAVE ADJUSTED TEMPS A BIT HIGHER FROM PREVIOUS FORECAST. ALSO
ADJUSTED CLOUD COVER TO BRING CURRENT. REMAINDER OF FORECAST
LOOKED PRETTY GOOD BUT DID UPDATE TO BRING CURRENT.
PREVIOUS DISCUSSION...
THE BEST CHANCE FOR ORGANIZED STORMS AND SEVERE WEATHER WILL BE
IN WESTERN NEW ENGLAND AS 0-6KM SHEAR INCREASES TO 35 KT BY LATE
AFTERNOON...BUT BEST LOW LEVEL CONVERGENCE MAY BE FURTHER E NEAR
THE COASTAL PLAIN. PRIMARY MODE OF CONVECTION SHOULD BE
MULTICELLULAR LINE SEGMENTS WITH DAMAGING WIND THE GREATEST THREAT
FROM ANY SEVERE STORMS...ALONG WITH HEAVY DOWNPOURS IN HIGH PWAT
AIRMASS.
ANOTHER RATHER HOT AND HUMID DAY ACROSS SNE. IF THE CLOUD COVER
REMAIN BROKEN AND THIN...IT WONT TAKE MUCH FOR TEMPS TO SOAR INTO
THE LOW TO MID 90S AS IT IS ALREADY FAIRLY WARM PER THIS MORNING
LOWS. MAIN HEATING WILL BE ACROSS RI AND E MA WHERE MOST SUNSHINE
IS EXPECTED. DEWPOINTS IN THE LOWER-MID 70S WILL RESULT IN HEAT
INDICES OF 100-105 FOR HOTTEST SPOTS IN THE LOWER CT VALLEY AND
MUCH OF E MA AND RI WHERE HEAT ADVISORIES ARE IN EFFECT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
SCT SHOWERS AND TSTMS MAY LINGER ACROSS THE COASTAL PLAIN AND S
COAST INTO THE EVENING BEFORE ACTIVITY DISSIPATES AND MOVES
OFFSHORE. COLD FRONT WILL MOVE S ACROSS THE REGION TONIGHT BUT
NOT CLEARING THE S COAST UNTIL CLOSER TO 12Z SUN.
SUNDAY...
WEAK FRONT WILL STALL S OF NEW ENG WITH WEAK HIGH PRES BUILDING
TO THE N. WHILE IT WILL BE NOTICEABLY COOLER...850 MB TEMPS 14-16C
SO IT WILL STILL BE RATHER WARM WITH TEMPS IN THE MID TO UPPER
80S...COOLER HIGHER TERRAIN AS WELL AS IMMEDIATE COAST WHERE
COASTAL SEABREEZES ARE LIKELY. DEWPOINTS MAY DROP INTO THE UPPER
50S ACROSS N ZONES...BUT LIKELY REMAIN IN THE MID 60S CLOSER TO
THE COAST. LOW RISK FOR AN ISOLD SHOWER SUN AFTERNOON...OTHERWISE
DRY WEATHER WITH PT-MOSUNNY SKIES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HEADLINES...
* DRY AND SEASONABLE INTO MONDAY.
* SHOWERS AND THUNDERSTORMS RETURN FOR TUESDAY INTO WEDNESDAY.
* AN ACTIVE WEATHER PATTERN SETUP CONTINUES THROUGH THE LATE WEEK.
* NO SIGN OF OPPRESSIVE HEAT AND HUMIDITY RETURNING ANY TIME SOON.
*/OVERVIEW AND MODEL CONSENSUS...
WHILE BETTER CONTINUITY HAS EMERGED INTO THE MIDWEEK...THERE IS
STILL SOME UNCERTAINTY CONCERNING THE ABNORMAL SETUP SET TO EVOLVE
INTO THE LATTER PORTION OF THE FORECAST. LATEST OPERATIONAL RUNS OF
THE ECMWF HAVE COME INTO BETTER AGREEMENT WITH ITS ENSEMBLE MEAN
WHILE THE RUN-TO-RUN CONTINUITY OF THE GFS HAS NOT EXHIBITED THE
SAME.
AM IN FAVOR OF THE MORE AMPLIFIED PATTERN WITH THE BAROCLINIC ZONE
DIPPING INTO THE GULF COASTAL STATES AS EMPHASIZED BY THE ECMWF INTO
THE FOLLOWING WEEKEND. AGREE WITH WPC ASSESSMENT AND ACCOMPANYING
FORECAST GUIDANCE. THUS NOT SEEING A RETURN OF OPPRESSIVE HEAT AND
HUMIDITY ANY TIME SOON RATHER A MORE ACTIVE AND SEASONABLE PATTERN.
SURFACE OUTCOMES REMAIN UNCERTAIN SO FAR OUT IN THE FORECAST BUT IT
IS LIKELY THAT PACIFIC WAVES TRANSLATING AND EVOLVING THROUGH THE
LONG WAVE PATTERN WILL NOT ONLY AMPLIFY THE PATTERN BUT ALSO LEAD
TO SUCCESSIVE ROUNDS OF SHOWERS AND THUNDERSTORMS.
*/DAY-TO-DAY DETAILS...
*/SUNDAY NIGHT INTO MONDAY...
WILL KEEP THE FORECAST PERIOD MOSTLY DRY KEEPING COOLER AND DRIER
HIGH PRESSURE IN CONTROL. POOR MID-LEVEL LAPSE RATES. SUBSTANTIAL MID-
LEVEL DRY AIR IN PLACE WITH ACCOMPANYING RIDGING. LITTLE IN THE
WAY OF DYNAMICS AND ONLY LOW-LEVEL FORCING WILL BE ALONG SEA-
BREEZE FRONTS AS THE EARLY WEEKEND COLD FRONT WILL STALL SOUTH OF
NEW ENGLAND...ORIENTED WEST TO EAST IN PROXIMITY TO SOUTHERN
PA/NJ.
THERE ARE SUBTLE HINTS OF PERHAPS SOME PRECIPITATION...THE 20.0Z NAM
THE MOST PRONOUNCED SOLUTION. EVALUATING FURTHER...THE NORTHEASTERN
CONUS IS WITHIN THE RIGHT-REAR QUADRANT OF THE UPPER-LEVEL JET
COINCIDENT WITH THE MID-LEVEL /H85/ THERMAL GRADIENT. BUT WITH THE
DRY AIR AND POOR LAPSE RATES...JUST DO NOT HAVE THE CONFIDENCE IN
GOING WITH CHANCE POPS.
WILL KEEP CONDITIONS CLOSE TO SEASONABLE. BETTER CHANCE FOR
CLOUDS DURING THE PERIOD WILL BE ALONG THE SOUTH-COAST WITH CLOSER
PROXIMITY TO THE AFOREMENTIONED COLD FRONT.
*/MONDAY NIGHT INTO WEDNESDAY...
THERE IS BETTER AGREEMENT ON THE EVOLUTION OF PACIFIC DISTURBANCE
TRANSLATING THROUGH THE MARITIME FLOW AND INTERACTING WITH A STRONG
AREA OF LOW PRESSURE ACROSS NORTHERN QUEBEC. THE GENERAL THEME AT
THE SURFACE IS FOR AN AREA OF LOW PRESSURE TO DEVELOP NORTH OF THE
GREAT LAKES REGION...UNDERGO MATURATION AND OCCLUSION DURING THE
TIME FRAME INTO NORTHERN QUEBEC. THE SUBSEQUENT INFLUENCE OF RETURN
SOUTHERN FLOW ACROSS THE NORTHEASTERN CONUS LIFTS THE OFFSHORE FRONT
NORTH AS A WARM FRONT EARLY IN THE PERIOD...FOLLOWED BY A TRAILING
ATTENDANT COLD FRONT TO THE AFOREMENTIONED LOW LATE INTO WEDNESDAY.
WHILE SOME DIFFERENCES CONCERNING TIMING AND SUBSEQUENT SURFACE
OUTCOMES...THERE IS A GENERAL THEME OF PERIODS OF SHOWERS AND
THUNDERSTORMS LOCALIZED WHERE LOW-LEVEL CONVERGENCE ALONG FRONTAL
BOUNDARIES COUPLED WITH MID- TO UPPER-LEVEL DYNAMICS ALOFT
RESULTING IN DEEP-LAYER ASCENT. CHANCE POPS
WARRANTED...ESPECIALLY MONDAY NIGHT INTO TUESDAY NIGHT. SHEAR IS
PRONOUNCED...BUT INSTABILITY IS LACKING LIKELY DUE TO POOR MID-
LEVEL LAPSE RATES AND ANTICIPATED CLOUDY MESS. NOTED BY THE PRIOR
FORECASTER...HIGH PWATS UP TO 2 INCHES PRESENTS THE THREAT OF
HEAVY RAINFALL AND LOCALIZED FLOODING.
WILL PREVAIL WITH CONDITIONS AT OR SLIGHTLY ABOVE SEASONABLE WITH
EXPECTED SOUTHERLY FLOW. SHOULD SEE THE RETURN OF MUGGY CONDITIONS.
WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING TUESDAY NIGHT
INTO WEDNESDAY.
*/THURSDAY INTO THE WEEK...
GREATER CONFIDENCE TOWARDS THE DETERMINISTIC 19.12Z ECMWF WITH
IMPROVED AGREEMENT WITH ITS ENSEMBLE MEAN...AND BETTER RUN-TO-RUN
CONSISTENCY. STILL THERE IS SOME UNCERTAINTY WITH HOW PACIFIC ENERGY
EVOLVES THROUGH THE BASE OF THE BROADER TROUGHING PATTERN OVER THE
EASTERN TWO-THIRDS OF THE CONUS...THOUGH WPC/HPC HAS NOTED THAT
FORECAST GUIDANCE HAS TRENDED WITH A MORE AMPLIFIED TROUGH PATTERN
WITH A COLD UPPER-LOW DIPPING INTO THE GREAT LAKES REGION.
AS STATED YESTERDAY...CONTINUED CERTAINTY THAT THE NORTHEASTERN
CONUS REMAINS IN THE MARITIME FLOW RESULTING IN AN ACTIVE WEATHER
PATTERN AND SEASONABLE CONDITIONS. CHANCE POPS WARRANTED WITH THE
EXPECTATION FOR SHOWERS AND THUNDERSTORMS AT TIMES...NOT SPECULATING
ON SEVERE WEATHER AT THIS TIME...THOUGH IF THE TROUGH EFFECTIVELY
TAPS INTO TROPICAL MOISTURE...THEN HEAVY RAIN AND POTENTIAL FLOODING
WILL BE A CONCERN. WILL KEEP CONDITIONS AT SEASONABLE LEVELS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH SUNDAY...
HAZE AND HIGH CLOUDS TO BE AN ISSUE THIS MORNING...GRADUALLY
BURNING OFF THROUGH THE DAY. EXPECTING AN INCREASE IN AREAL
COVERAGE OF SHRA/TSRA INTO THIS AFTERNOON ACROSS WESTERN AND
CENTRAL PORTIONS OF NEW ENGLAND. HAVE PREVAILED -SHRA VCTS
ACCORDINGLY MAINLY FOR THE AFTERNOON PERIOD AROUND THE MASS
TURNPIKE...SULKING SOUTH TO THE COAST TOWARDS SUNDOWN AND OUT TO
SEA INTO THE EVENING.
WITH ANY TSRA...LOW-VFR CIGS WITH MVFR/IFR VSBYS WILL BE
POSSIBLE. UNCERTAINTY ON LOCATION AND EVOLUTION OF TSRA SO DID NOT
PREVAIL IN THE TAF. GUSTY SW WINDS AHEAD OF AN APPROACHING COLD
FRONT ANTICIPATED TO SWEEP THROUGH THE TERMINALS LATE TONIGHT INTO
SUNDAY MORNING...WINDS BACKING OUT OF THE NORTH-NORTHWEST AND
WEAKENING.
COASTAL FOG MAY DEVELOP AHEAD OF THE COLD FRONT. SHOULD SEE
IMPROVEMENT THEREAFTER WITH DRIER AIR FILTERING IN. PREVAILING
VFR FOR SUNDAY WITH LIGHT NORTH-NORTHWEST WINDS...SEA-BREEZES
ALONG THE SHORES.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP STORMS OUT
OF THE TERMINAL FOR NOW. GUSTY SOUTHWEST WINDS DURING THE DAY.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. PREVAILING -SHRA VCTS
WITH EXPECTATION OF AFTERNOON STORMS...BUT UNCERTAIN ON SPECIFIC
IMPACTS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
VFR. LIGHT AND VARIABLE WINDS. SEA-BREEZES ALONG THE SHORELINES.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
WINDS TURNING SOUTHERLY AND GUSTY AT TIMES. PERIODS OF SHRA/TSRA.
WILL SEE TEMPO MVFR-IFR IMPACTS WITH WET WEATHER. COULD SEE A
RETURN OF SOUTH-COASTAL DENSE FOG. COLD FRONT LATE IN THE PERIOD
WILL FORCE WINDS TO BACK NORTH-NORTHWEST.
THURSDAY...MODERATE CONFIDENCE.
AFOREMENTIONED COLD FRONT MAY LINGER IN PROXIMITY TO SOUTHERN NEW
ENGLAND ACTING AS A FOCUS FOR CONTINUED WET WEATHER AND PERHAPS MVFR-
IFR IMPACTS AT TIMES. COASTAL FOG MAY ALSO BE AN ISSUE ALONG THE
SOUTH-COAST.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH SUNDAY.
THROUGH THIS EVENING...A FEW GUSTS TO 25 KT POSSIBLE OVER THE
NEARSHORE WATERS THIS AFTERNOON. SEAS REMAIN AROUND 5-6 FT ON THE
OPEN SOUTHERN WATERS AS WELL AS RI SOUND. SCT AFTN/EVENING TSTMS
POSSIBLE.
TONIGHT...SW WINDS WILL SHIFT TO THE NW LATE TONIGHT AS COLD FRONT
MOVES THROUGH. SCA SEAS CONTINUE OVER SOUTHERN WATERS. TSTMS
POSSIBLE SOUTH WATERS AS FRONTAL DEPARTS SLOWLY.
SUNDAY...E/SE WINDS DEVELOPING MAINLY UNDER 15 KT. SEAS SUBSIDING
BELOW SCA THRESHOLDS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
HIGH PRESSURE IN CONTROL. LIGHT AND VARIABLE WINDS GRADUALLY
BACKING OUT OF THE SOUTH. SEAS BELOW 5 FEET OVER ALL WATERS.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
INCREASE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS. WINDS OUT OF
THE SOUTH-SOUTHWEST INCREASING. GUSTS UP TO 20 KTS POSSIBLE. FETCH
RESULTING IN SEAS BUILDING ABOVE 5 FEET OVER THE SOUTH-SOUTHEAST
WATERS. COLD FRONT SLIDES INTO THE WATERS WEDNESDAY ALLOWING WINDS
TO DIMINISH. COASTAL FOG MAY BE AN ISSUE ALONG THE SOUTH-SHORE WITH
VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
THURSDAY...MODERATE CONFIDENCE.
COLD FRONT WAVERS AS IT STALLS IN PROXIMITY TO SOUTHERN NEW ENGLAND.
CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE. THE
LIGHTER WIND FLOW ALLOWS SEAS TO SUBSIDE. COASTAL FOG MAY CONTINUE
TO BE AN ISSUE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR CTZ002>004.
MA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MAZ005>007-
011>021.
NH...NONE.
RI...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR RIZ001>005.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR ANZ235-254.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ255-256.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL/EVT
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
749 AM EDT SAT JUL 20 2013
.SYNOPSIS...
ONE MORE HOT AND HUMID DAY IS EXPECTED TODAY ALONG WITH SCATTERED
STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AS A COLD FRONT
APPROACHES FROM THE GREAT LAKES. THIS FRONT WILL BRING RELIEF FROM
THE EXCESSIVE HEAT AND HUMIDITY ON SUNDAY. MORE SEASONABLE BUT
HUMID CONDITIONS ARE EXPECTED FOR MUCH OF NEXT WEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
CONVECTION OVER THE EASTERN GREAT LAKES IS CERTAINLY GOING TO HAVE
CONSEQUENCES UPON THE REGIONS WEATHER. INCREASING CLOUD COVER IS
LIKELY TO LIMIT BOUNDARY LAYER DESTABILIZATION AND WARMING
TEMPERATURES AT THE SURFACE. ECHO PREVIOUS FORECASTERS THOUGHTS
ABOUT IMPACTS JUST TO HOW UNSTABLE IT GETS THIS AFTERNOON AND
POTENTIAL STRONG TO SEVERE WEATHER OUTCOMES.
FEEL THE LATEST HRRR AND THE WRF-ARW HAVE A GOOD HANDLE ON THE
PRESENT SITUATION. SHOWERS AND AN ISOLATED THUNDERSTORM ARE
POSSIBLE DURING THE MORNING HOURS. THIS ENERGY MAY DISSIPATE INTO
A SLIGHTLY DRIER AIRMASS PER THE 12Z CHATHAM SOUNDING. BUT AS ALSO
DISCERNED FROM THE CHATHAM SOUNDING...THERE IS A LOT OF POTENTIAL
INSTABILITY SHOULD THE BOUNDARY LAYER DESTABILIZE.
DIFFICULT TO PIN DOWN EXACTLY WHERE AND WHEN ANY THUNDERSTORMS
WILL DEVELOP AND EVOLVE FOR TODAY. AS NOTED BY THE PREVIOUS
FORECASTER...MLCAPES FORECAST TO REACH 1000-2000 J/KG BUT THERE
IS SOME UNCERTAINTY WITH THE AMOUNT OF SUNSHINE DUE TO CONVECTIVE
REMNANTS AND CLOUD COVER DRIFTING IN FROM THE WEST. MID-LEVEL
TEMPS ARE FORECAST TO BE ABOUT 3-4 DEGREES COOLER THAN YESTERDAY SO
THERE WILL BE MUCH LESS OF A CAP AND RIGHT ENTRANCE REGION OF
UPPER JET WILL BE APPROACHING FROM THE NORTH LATER TODAY.
FOCUS IS ON THE DEVELOPMENT OF A PRE-FRONTAL TROUGH AHEAD OF THE
MAIN SURFACE COLD FRONT WHICH MAY AID IN FOCUSING LOW LEVEL
CONVERGENCE FOR CONVECTION...THERE IS STILL AN EXPECTATION FOR
SCATTERED THUNDERSTORMS TO DEVELOP THIS AFTERNOON SHOULD CLOUD
COVER CLEAR OUT AS SUGGESTED BY THE HRRR.
AGAIN...THE BEST CHANCE FOR ORGANIZED STORMS AND SEVERE WEATHER
WILL BE IN WESTERN NEW ENGLAND AS 0-6KM SHEAR INCREASES TO 35 KT
BY LATE AFTERNOON...BUT BEST LOW LEVEL CONVERGENCE MAY BE FURTHER
E NEAR THE COASTAL PLAIN. PRIMARY MODE OF CONVECTION SHOULD BE
MULTICELLULAR LINE SEGMENTS WITH DAMAGING WIND THE GREATEST THREAT
FROM ANY SEVERE STORMS...ALONG WITH HEAVY DOWNPOURS IN HIGH PWAT
AIRMASS.
ANOTHER RATHER HOT AND HUMID DAY ACROSS SNE. IF THE CLOUD COVER
REMAIN BROKEN AND THIN...IT WONT TAKE MUCH FOR TEMPS TO SOAR INTO
THE LOW TO MID 90S AS IT IS ALREADY FAIRLY WARM PER THIS MORNING
LOWS. MAIN HEATING WILL BE ACROSS RI AND E MA WHERE MOST SUNSHINE
IS EXPECTED. DEWPOINTS 70-75 WILL RESULT IN HEAT INDICES OF 100-105
FOR HOTTEST SPOTS IN THE LOWER CT VALLEY AND MUCH OF E MA AND RI
WHERE HEAT ADVISORIES ARE IN EFFECT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
SCT SHOWERS AND TSTMS MAY LINGER ACROSS THE COASTAL PLAIN AND S
COAST INTO THE EVENING BEFORE ACTIVITY DISSIPATES AND MOVES
OFFSHORE. COLD FRONT WILL MOVE S ACROSS THE REGION TONIGHT BUT
NOT CLEARING THE S COAST UNTIL CLOSER TO 12Z SUN.
SUNDAY...
WEAK FRONT WILL STALL S OF NEW ENG WITH WEAK HIGH PRES BUILDING
TO THE N. WHILE IT WILL BE NOTICEABLY COOLER...850 MB TEMPS 14-16C
SO IT WILL STILL BE RATHER WARM WITH TEMPS IN THE MID TO UPPER
80S...COOLER HIGHER TERRAIN AS WELL AS IMMEDIATE COAST WHERE
COASTAL SEABREEZES ARE LIKELY. DEWPOINTS MAY DROP INTO THE UPPER
50S ACROSS N ZONES...BUT LIKELY REMAIN IN THE MID 60S CLOSER TO
THE COAST. LOW RISK FOR AN ISOLD SHOWER SUN AFTERNOON...OTHERWISE
DRY WEATHER WITH PT-MOSUNNY SKIES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HEADLINES...
* DRY AND SEASONABLE INTO MONDAY.
* SHOWERS AND THUNDERSTORMS RETURN FOR TUESDAY INTO WEDNESDAY.
* AN ACTIVE WEATHER PATTERN SETUP CONTINUES THROUGH THE LATE WEEK.
* NO SIGN OF OPPRESSIVE HEAT AND HUMIDITY RETURNING ANY TIME SOON.
*/OVERVIEW AND MODEL CONSENSUS...
WHILE BETTER CONTINUITY HAS EMERGED INTO THE MIDWEEK...THERE IS
STILL SOME UNCERTAINTY CONCERNING THE ABNORMAL SETUP SET TO EVOLVE
INTO THE LATTER PORTION OF THE FORECAST. LATEST OPERATIONAL RUNS OF
THE ECMWF HAVE COME INTO BETTER AGREEMENT WITH ITS ENSEMBLE MEAN
WHILE THE RUN-TO-RUN CONTINUITY OF THE GFS HAS NOT EXHIBITED THE
SAME.
AM IN FAVOR OF THE MORE AMPLIFIED PATTERN WITH THE BAROCLINIC ZONE
DIPPING INTO THE GULF COASTAL STATES AS EMPHASIZED BY THE ECMWF INTO
THE FOLLOWING WEEKEND. AGREE WITH WPC ASSESSMENT AND ACCOMPANYING
FORECAST GUIDANCE. THUS NOT SEEING A RETURN OF OPPRESSIVE HEAT AND
HUMIDITY ANY TIME SOON RATHER A MORE ACTIVE AND SEASONABLE PATTERN.
SURFACE OUTCOMES REMAIN UNCERTAIN SO FAR OUT IN THE FORECAST BUT IT
IS LIKELY THAT PACIFIC WAVES TRANSLATING AND EVOLVING THROUGH THE
LONGWAVE PATTERN WILL NOT ONLY AMPLIFY THE PATTERN BUT ALSO LEAD TO
SUCCESSIVE ROUNDS OF SHOWERS AND THUNDERSTORMS.
*/DAY-TO-DAY DETAILS...
*/SUNDAY NIGHT INTO MONDAY...
WILL KEEP THE FORECAST PERIOD MOSTLY DRY KEEPING COOLER AND DRIER
HIGH PRESSURE IN CONTROL. POOR MID-LEVEL LAPSE RATES. SUBSTANTIAL MID-
LEVEL DRY AIR IN PLACE WITH ACCOMPANYING RIDGING. LITTLE IN THE
WAY OF DYNAMICS AND ONLY LOW-LEVEL FORCING WILL BE ALONG SEA-
BREEZE FRONTS AS THE EARLY WEEKEND COLD FRONT WILL STALL SOUTH OF
NEW ENGLAND...ORIENTED WEST TO EAST IN PROXIMITY TO SOUTHERN
PA/NJ.
THERE ARE SUBTLE HINTS OF PERHAPS SOME PRECIPITATION...THE 20.0Z NAM
THE MOST PRONOUNCED SOLUTION. EVALUATING FURTHER...THE NORTHEASTERN
CONUS IS WITHIN THE RIGHT-REAR QUADRANT OF THE UPPER-LEVEL JET
COINCIDENT WITH THE MID-LEVEL /H85/ THERMAL GRADIENT. BUT WITH THE
DRY AIR AND POOR LAPSE RATES...JUST DO NOT HAVE THE CONFIDENCE IN
GOING WITH CHANCE POPS.
WILL KEEP CONDITIONS CLOSE TO SEASONABLE. BETTER CHANCE FOR
CLOUDS DURING THE PERIOD WILL BE ALONG THE SOUTH-COAST WITH CLOSER
PROXIMITY TO THE AFOREMENTIONED COLD FRONT.
*/MONDAY NIGHT INTO WEDNESDAY...
THERE IS BETTER AGREEMENT ON THE EVOLUTION OF PACIFIC DISTURBANCE
TRANSLATING THROUGH THE MARITIME FLOW AND INTERACTING WITH A STRONG
AREA OF LOW PRESSURE ACROSS NORTHERN QUEBEC. THE GENERAL THEME AT
THE SURFACE IS FOR AN AREA OF LOW PRESSURE TO DEVELOP NORTH OF THE
GREAT LAKES REGION...UNDERGO MATURATION AND OCCLUSION DURING THE
TIME FRAME INTO NORTHERN QUEBEC. THE SUBSEQUENT INFLUENCE OF RETURN
SOUTHERN FLOW ACROSS THE NORTHEASTERN CONUS LIFTS THE OFFSHORE FRONT
NORTH AS A WARM FRONT EARLY IN THE PERIOD...FOLLOWED BY A TRAILING
ATTENDANT COLD FRONT TO THE AFOREMENTIONED LOW LATE INTO WEDNESDAY.
WHILE SOME DIFFERENCES CONCERNING TIMING AND SUBSEQUENT SURFACE
OUTCOMES...THERE IS A GENERAL THEME OF PERIODS OF SHOWERS AND
THUNDERSTORMS LOCALIZED WHERE LOW-LEVEL CONVERGENCE ALONG FRONTAL
BOUNDARIES COUPLED WITH MID- TO UPPER-LEVEL DYNAMICS ALOFT
RESULTING IN DEEP-LAYER ASCENT. CHANCE POPS
WARRANTED...ESPECIALLY MONDAY NIGHT INTO TUESDAY NIGHT. SHEAR IS
PRONOUNCED...BUT INSTABILITY IS LACKING LIKELY DUE TO POOR MID-
LEVEL LAPSE RATES AND ANTICIPATED CLOUDY MESS. NOTED BY THE PRIOR
FORECASTER...HIGH PWATS UP TO 2 INCHES PRESENTS THE THREAT OF
HEAVY RAINFALL AND LOCALIZED FLOODING.
WILL PREVAIL WITH CONDITIONS AT OR SLIGHTLY ABOVE SEASONABLE WITH
EXPECTED SOUTHERLY FLOW. SHOULD SEE THE RETURN OF MUGGY CONDITIONS.
WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING TUESDAY NIGHT
INTO WEDNESDAY.
*/THURSDAY INTO THE WEEK...
GREATER CONFIDENCE TOWARDS THE DETERMINISTIC 19.12Z ECMWF WITH
IMPROVED AGREEMENT WITH ITS ENSEMBLE MEAN...AND BETTER RUN-TO-RUN
CONSISTENCY. STILL THERE IS SOME UNCERTAINTY WITH HOW PACIFIC ENERGY
EVOLVES THROUGH THE BASE OF THE BROADER TROUGHING PATTERN OVER THE
EASTERN TWO-THIRDS OF THE CONUS...THOUGH WPC/HPC HAS NOTED THAT
FORECAST GUIDANCE HAS TRENDED WITH A MORE AMPLIFIED TROUGH PATTERN
WITH A COLD UPPER-LOW DIPPING INTO THE GREAT LAKES REGION.
AS STATED YESTERDAY...CONTINUED CERTAINTY THAT THE NORTHEASTERN
CONUS REMAINS IN THE MARITIME FLOW RESULTING IN AN ACTIVE WEATHER
PATTERN AND SEASONABLE CONDITIONS. CHANCE POPS WARRANTED WITH THE
EXPECTATION FOR SHOWERS AND THUNDERSTORMS AT TIMES...NOT SPECULATING
ON SEVERE WEATHER AT THIS TIME...THOUGH IF THE TROUGH EFFECTIVELY
TAPS INTO TROPICAL MOISTURE...THEN HEAVY RAIN AND POTENTIAL FLOODING
WILL BE A CONCERN. WILL KEEP CONDITIONS AT SEASONABLE LEVELS.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH SUNDAY...
HAZE AND HIGH CLOUDS TO BE AN ISSUE THIS MORNING...GRADUALLY
BURNING OFF THROUGH THE DAY. EXPECTING AN INCREASE IN AREAL
COVERAGE OF SHRA/TSRA INTO THIS AFTERNOON ACROSS WESTERN AND
CENTRAL PORTIONS OF NEW ENGLAND. HAVE PREVAILED -SHRA VCTS
ACCORDINGLY MAINLY FOR THE AFTERNOON PERIOD AROUND THE MASS
TURNPIKE...SULKING SOUTH TO THE COAST TOWARDS SUNDOWN AND OUT TO
SEA INTO THE EVENING.
WITH ANY TSRA...LOW-VFR CIGS WITH MVFR/IFR VSBYS WILL BE
POSSIBLE. UNCERTAINTY ON LOCATION AND EVOLUTION OF TSRA SO DID NOT
PREVAIL IN THE TAF. GUSTY SW WINDS AHEAD OF AN APPROACHING COLD
FRONT ANTICIPATED TO SWEEP THROUGH THE TERMINALS LATE TONIGHT INTO
SUNDAY MORNING...WINDS BACKING OUT OF THE NORTH-NORTHWEST AND
WEAKENING.
COASTAL FOG MAY DEVELOP AHEAD OF THE COLD FRONT. SHOULD SEE
IMPROVEMENT THEREAFTER WITH DRIER AIR FILTERING IN. PREVAILING
VFR FOR SUNDAY WITH LIGHT NORTH-NORTHWEST WINDS...SEA-BREEZES
ALONG THE SHORES.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP STORMS OUT
OF THE TERMINAL FOR NOW. GUSTY SOUTHWEST WINDS DURING THE DAY.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. PREVAILING -SHRA VCTS
WITH EXPECTATION OF AFTERNOON STORMS...BUT UNCERTAIN ON SPECIFIC
IMPACTS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
VFR. LIGHT AND VARIABLE WINDS. SEA-BREEZES ALONG THE SHORELINES.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
WINDS TURNING SOUTHERLY AND GUSTY AT TIMES. PERIODS OF SHRA/TSRA.
WILL SEE TEMPO MVFR-IFR IMPACTS WITH WET WEATHER. COULD SEE A
RETURN OF SOUTH-COASTAL DENSE FOG. COLD FRONT LATE IN THE PERIOD
WILL FORCE WINDS TO BACK NORTH-NORTHWEST.
THURSDAY...MODERATE CONFIDENCE.
AFOREMENTIONED COLD FRONT MAY LINGER IN PROXIMITY TO SOUTHERN NEW
ENGLAND ACTING AS A FOCUS FOR CONTINUED WET WEATHER AND PERHAPS MVFR-
IFR IMPACTS AT TIMES. COASTAL FOG MAY ALSO BE AN ISSUE ALONG THE
SOUTH-COAST.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH SUNDAY.
TODAY...A FEW GUSTS TO 25 KT POSSIBLE OVER THE NEARSHORE WATERS
THIS AFTERNOON. SCA SEAS OVER THE OPEN SOUTHERN WATERS. SCT
AFTN/EVENING TSTMS POSSIBLE.
TONIGHT...SW WINDS WILL SHIFT TO THE NW LATE TONIGHT AS COLD FRONT
MOVES THROUGH. SCA SEAS CONTINUE OVER SOUTHERN WATERS. TSTMS
POSSIBLE SOUTH WATERS AS FRONTAL DEPARTS SLOWLY.
SUNDAY...E/SE WINDS DEVELOPING MAINLY UNDER 15 KT. SEAS SUBSIDING
BELOW SCA THRESHOLDS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
HIGH PRESSURE IN CONTROL. LIGHT AND VARIABLE WINDS GRADUALLY
BACKING OUT OF THE SOUTH. SEAS BELOW 5 FEET OVER ALL WATERS.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
INCREASE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS. WINDS OUT OF
THE SOUTH-SOUTHWEST INCREASING. GUSTS UP TO 20 KTS POSSIBLE. FETCH
RESULTING IN SEAS BUILDING ABOVE 5 FEET OVER THE SOUTH-SOUTHEAST
WATERS. COLD FRONT SLIDES INTO THE WATERS WEDNESDAY ALLOWING WINDS
TO DIMINISH. COASTAL FOG MAY BE AN ISSUE ALONG THE SOUTH-SHORE WITH
VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
THURSDAY...MODERATE CONFIDENCE.
COLD FRONT WAVERS AS IT STALLS IN PROXIMITY TO SOUTHERN NEW ENGLAND.
CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE. THE
LIGHTER WIND FLOW ALLOWS SEAS TO SUBSIDE. COASTAL FOG MAY CONTINUE
TO BE AN ISSUE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
CTZ002>004.
MA...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
MAZ005>007-011>021.
NH...NONE.
RI...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
RIZ001>005.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR ANZ235-254.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ255-256.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
355 AM EDT Sat Jul 20 2013
.NEAR TERM [Today and Tonight]...
The high-resolution model guidance appears to have been reasonably
accurate in depicting an increase in convective coverage and rain
rates around 06-08 UTC. The showers that have developed so far
appear to be dominated by warm rain processes - low-topped
convection that is very efficient in producing rainfall. The TLH
airport recorded around one half inch of rain in just under a half
hour with one of these showers. The HRRR and preponderance of CAM
guidance shows a general 1-2" of rain on average can be expected
through mid-afternoon over most of our Florida zones (where the
heaviest rain is most likely). However, the vast majority of those
models also show localized amounts in the 7-9" range, which would
likely be sufficient to cause localized flash flooding. Because of
this, we have issued a Flash Flood Watch in effect until 23 UTC for
all of our Florida zones.
PoPs were adjusted to show 60-80% values this morning across our
Florida zones, with "likely" PoPs (60-70%) spreading north into our
Alabama and Georgia zones in the late morning and afternoon. The
abundance of rain and cloud cover will likely once again restrict
the diurnal temperature range, so high temperatures were kept cooler
than normal values, and similar to the inherited forecast.
Indications are that convective coverage will diminish between 21
and 03 UTC, with a lull tomorrow evening.
&&
.SHORT TERM [Sunday Through Monday]...
While at this time yesterday it had appeared that there would be
some legitimate hope that a brief period of Upper level ridging
could push far enough northward in the Gulf of Mexico to at least
give our region a brief break in the unsettled weather, each
consecutive run of the ECMWF continues to squash that little bit of
hope. If the Upper ridge stays weak and in the Central Gulf of
Mexico, the probability of conditions that are wetter and cooler
than climo will increase, and for those looking for a break in the
persistent Upper trough (and accompanying sunnier and drier
conditions) may have to wait until next summer.
&&
.LONG TERM [Monday Night through Friday]...
The GFS and ECMWF forecast a 500mb trough to develop over the
Southeast over the upcoming work week. It`s difficult to forecast
specifics in such patterns as there will undoubtedly be minor short
waves rotating through this broader trough, which can help trigger
periods of active deep moist convection (sometimes even overnight).
The best approach is to "broad brush" above-average rain chances
(generally 50-60% each day, and 20-30% each night) across the
region, which is near the GFS-ECMWF MOS PoP blend. Temperatures will
be near average, with highs in the lower to mid 90s (inland) and
lows in the 70s.
&&
.AVIATION [through 12 UTC Sunday]...
Some IFR-MVFR CIGS could develop at our three northern terminals
(DHN, ABY, VLD) out ahead of the rain showers that are developing
near the Gulf. These will likely diminish as the rain advances north
this morning. Meanwhile, MVFR-VFR should prevail at TLH and ECP,
with tropical rain showers having the potential to reduce visibility
at times to IFR. These tropical rain showers will spread inland
during the day, with the potential to eventually affect the
remaining terminals (ABY, DHN, VLD). Rain will diminish by 21-03 UTC
with VFR through the evening.
&&
.MARINE...
Moderate onshore winds today have created slightly higher seas than
expected, so did bump up seas about 1 foot across the board for
today. Winds and seas will diminish a bit back to more typical
summertime levels on Sunday and Monday, before becoming moderate
again out of the west by mid week, as the surface pressure pattern
increases slightly.
&&
.FIRE WEATHER...
Red flag conditions are not expected for the next several days.
&&
.HYDROLOGY...
Numerous tropical rain showers and rain bands are beginning to
develop early this morning in a very moist environment. The humid
air mass is due to a large plume of tropical moisture. A variety of
model guidance shows a general inch of rainfall averaged across all
of the Florida panhandle and big bend. However, there are also
indications that localized amounts could be well in excess of that.
Small heavy rain bands are not uncommon in a tropical environment
such as this, and they can lead to localized flash flooding. The
rain should begin to decrease in coverage closer to sunset. Impacts
on area rivers are difficult to pinpoint at this time, but certainly
areas near Bruce, Lamont, and Newport in Florida should be on alert
for potential rises back to Flood Stage.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 84 73 90 74 91 / 80 30 60 30 40
Panama City 84 76 88 76 88 / 70 50 60 30 40
Dothan 87 73 90 73 91 / 70 30 60 30 50
Albany 87 73 91 74 91 / 70 30 60 30 50
Valdosta 85 72 92 73 92 / 70 30 60 30 50
Cross City 88 73 90 73 90 / 60 30 60 20 40
Apalachicola 84 76 88 75 88 / 70 50 50 20 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...FLASH FLOOD WATCH through this evening for Calhoun-Central
Walton-Coastal Bay-Coastal Dixie-Coastal Franklin-Coastal
Gulf-Coastal Jefferson-Coastal Taylor-Coastal Wakulla-
Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin-
Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla-
Inland Walton-Jackson-Lafayette-Leon-Liberty-Madison-
South Walton-Washington.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Gould
LONG TERM...Fournier
AVIATION...Lamers
MARINE...Gould
FIRE WEATHER...Lamers
HYDROLOGY...Lamers/Gould
AREA FORECAST DISCUSSION
NWS LINCOLN IL
853 PM CDT SUN JUL 21 2013
.DISCUSSION...
ISSUED 850 PM CDT SUN JUL 21 2013
UPDATED THE FORECAST TONIGHT TO INCREASE CHANCES OF SHOWERS ALONG
WITH A FEW THUNDERSTORMS. ALSO NUDGED UP LOW TEMPERATURES A DEGREE
OR TWO TO AROUND 70F...DUE TO MOIST DEWPOINTS CURRENTLY IN THE LOW
TO MID 70S. A FEW POCKETS OF LOCALLY HEAVY RAINS OF 1.5 TO 3 INCHES
ALSO TO OCCUR TONIGHT ESPECIALLY FROM I-72 SOUTH...AS JACKSONVILLE
HAS EXPERIENCED SINCE 5 PM.
THE HRRR MODEL HAS BEEN HANDLING THIS WEATHER SYSTEM THE BEST SO
FAR SO LEANED ON THIS MODEL FOR TONIGHT`S FORECAST. SHOWERS AND A
FEW THUNDERSTORMS TO SPREAD INTO EASTCENTRAL IL NEXT NEW HOURS...
THEN DIMINISH FROM WEST TO EAST LATE THIS EVENING AND OVERNIGHT.
A SHORT WAVE MOVING INTO CENTRAL IL THIS EVENING AND EXITING SE OF
AREA MONDAY MORNING WILL KEEP LIKELY CHANCES OF SHOWERS AND FEW
THUNDERSTORMS PAST SUNDOWN TONIGHT AND LIKELY CHANCES CONTINUE OVER
EASTERN IL OVERNIGHT...WHILE DIMINISHING TO SLIGHT CHANCE IN THE WEST.
A QUASI STATIIONARY FRONTAL BOUNDARY OVER NE PARTS OF IA/IL AND
INTO CENTRAL INDIANA WILL GRADUALLY WEAKEN THROUGH MONDAY...WITH
CENTRAL/SE IL STAYING ON THE SOUTH SIDE (MILD/MOIST SIDE) OF THE
BOUNDARY. TEMPS CURRENTLY IN THE 70S TO ONLY SLIP TOWARD 70F FOR
LOWS OVERNIGHT WHICH JACKSONVILLE IS CURRENTLY DOWN TO WITH HEAVY
RAINS PAST FEW HOURS FROM THUNDERSTORMS. EXPECT LIGHT SSE TO
VARIABLE WINDS TONIGHT WITH SOME FOG POSSIBLE OVERNIGHT INTO MID
MORNING MONDAY WITH VSBYS DOWN TO 1-3 MILES.
07
&&
.AVIATION...
ISSUED 700 PM CDT SUN JUL 21 2013
LEANED ON THE HRRR MODEL FOR QPF FIELDS WITH ARRIVAL OF SHOWERS
AND THUNDERSTORMS FROM WEST TO EAST DURING THIS EVENING AND
DIMINISHING OVERNIGHT. HAVE MVFR CEILINGS 1.5-3K FT POSSIBLE TONIGHT
WITH PRECIPITATION ALONG WITH VSBYS RESTRICTED DOWN TO 1.5-3 MILES
IN HEAVIER RAIN SHOWERS. SHOWERS AND A FEW THUNDERSTORMS ARE WEST
OF I-55 AND TO SPREAD EAST TO DEC AND CMI IN THE NEXT FEW
HOURS...THEN DIMINISH FROM WEST TO EAST FROM 05Z-08Z. SOME FOG
POSSIBLE OVERNIGHT INTO MON MORNING WITH VSBYS 2-4 MILES AND THEN
LIFTING TO LIGHT FOG/HAZE OF 4-6 MILES BETWEEN 14-15Z AS MVFR
CEILINGS LIFT TO VFR LATER MON MORNING. SOUTH WINDS TO STAY FAIRLY
LIGHT FROM 4-8 KTS THIS EVENING AND LIGHT AND VARIABLE OVERNIGHT
AND SW 4-7 KTS MONDAY.
07
&&
.PREV DISCUSSION...
ISSUED 239 PM CDT SUN JUL 21 2013
MAIN CONCERNS THIS PACKAGE WILL CONTINUE TO BE PCPN CHANCES FOR
THE SHORT TERM AND THEN PCPN CHANCES AGAIN AT THE END OF THE WEEK
AND INTO THE WEEKEND...IN THE LONG TERM PERIOD.
MODELS SHOW GOOD AGREEMENT WITH KEEPING THE MID LEVEL NORTHWEST
FLOW IN PLACE...WITH A RIDGE BUILDING OUT OVER THE ROCKIE MOUNTAIN
REGION...ALL THROUGH MID WEEK. THE NORTHWEST FLOW WILL ALSO
CONTINUE INTO THE EXTENDED PERIOD AND MODELS LOOK OK HERE TOO
UNTIL LATE IN THE WEEK AND THE WEEKEND. ECMWF APPEARS TO BE
STRONGER WITH A MID LEVEL SYSTEM COMING DOWN INTO THE AREA DURING
THE END OF THE PERIOD.
SHORT TERM...TONIGHT THROUGH WEDNESDAY
FRONTAL SYSTEM OVER THE AREA THIS AFTERNOON WILL GRADUALLY WASHOUT
TONIGHT THROUGH TOMORROW AS A STRONGER WEATHER SYSTEM DEVELOPS OUT
IN THE PLAINS. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS
THE ENTIRE CWA THIS EVENING AND THEN IN THE EAST AFTER
MIDNIGHT...WITH CHANCES BACK TO THE WEST. LIGHT SHOWERS ARE
ONGOING BUT REMNANTS OF AN MCS IN IOWA HAVE CONTINUED TO GET
STRONGER IN SOUTH CENTRAL IOWA AND WILL MOVE EAST-SOUTHEAST INTO
THE CWA THIS EVENING AND THROUGH TONIGHT. BELIEVE THIS
LINE/COMPLEX OF STORMS WILL FOLLOW THE STATIONARY BOUNDARY OVER
THE AREA AS IT MOVES EAST-SOUTHEAST. VARIOUS SHORT TERM MODELS
FORECAST THIS AREA OF STORMS EAST AND SOUTHEAST INTO CENTRAL
ILLINOIS THIS EVENING...THEREFORE CONFIDENCE IS HIGH ENOUGH FOR
LIKELY POPS. NO SEVERE IS EXPECTED WITH THESE STORMS...BUT LOCALLY
HEAVY RAINFALL AND DEADLY LIGHTNING WILL BE LIKELY. PCPN WILL
DIMINISH TOMORROW...BUT WITH LOTS OF LOW LEVEL MOISTURE AND A
STATIONARY BOUNDARY IN THE AREA...CANT RULE OUT A CHANCE OF
THUNDERSTORMS SOMEWHERE TOMORROW. PCPN CHANCES WILL CONTINUE AND
INCREASE INTO TOMORROW NIGHT AND TUESDAY AS ANOTHER...STRONGER
FRONT PUSHES INTO AND THROUGH THE AREA. FORECAST FOR THIS FRONT
APPEAR TO BE THAT IT WILL PUSH SHOULD OF THE STATE LATE TUE NIGHT
AND THEN BRING DRIER AND LESS HUMID AIR INTO THE REGION FOR
WEDNESDAY.
APPEARS TEMPS WILL BE QUITE WARM ONE MORE DAY TOMORROW. THEN
ADDITIONAL CLOUD COVER AND PCPN WILL CAUSE TEMPS TO BE SLIGHTLY
COOLER FOR TUESDAY. MUCH COOLER TEMPS ARE THEN EXPECTED AFTER THE
FRONT MOVES THROUGH THE AREA FOR WEDNESDAY.
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
DRY WEATHER WILL CONTINUE THROUGH THUR NIGHT AS NORTHWEST FLOW
WILL CONTINUE ACROSS THE AREA. A STRONGER SYSTEM/SHORT WAVE TROUGH
WILL THEN DEVELOP AND MOVE TOWARD THE AREA FOR LATE IN THE WEEK.
ECMWF IS STRONGER AND LOOKS MORE CONSISTENT FROM PREVIOUS RUNS WITH
THIS NEXT SYSTEM...THAN THE GFS. LEANING TOWARD THE ECMWF MODEL
GIVES A FORECAST OF PCPN CHANCES FOR FRIDAY THROUGH SATURDAY
NIGHT...SOMEWHERE IN THE CWA...THEN DRY WEATHER POSSIBLE SUNDAY.
STILL LOTS OF UNCERTAINTY WITH THIS PERIOD OF THE FORECAST SO
WOULD NOT BE SURPRISED TO SEE CHANGES TO IT OVER THE NEXT SEVERAL
DAYS.
TEMPS SHOULD BE COOLER THAN LAST WEEK GIVEN THE NORTHWEST FLOW AND
WENT COOLER THAN GUIDANCE FOR SAT AND SUNDAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
700 PM CDT SUN JUL 21 2013
.DISCUSSION...
ISSUED 239 PM CDT SUN JUL 21 2013
MAIN CONCERNS THIS PACKAGE WILL CONTINUE TO BE PCPN CHANCES FOR
THE SHORT TERM AND THEN PCPN CHANCES AGAIN AT THE END OF THE WEEK
AND INTO THE WEEKEND...IN THE LONG TERM PERIOD.
MODELS SHOW GOOD AGREEMENT WITH KEEPING THE MID LEVEL NORTHWEST
FLOW IN PLACE...WITH A RIDGE BUILDING OUT OVER THE ROCKIE MOUNTAIN
REGION...ALL THROUGH MID WEEK. THE NORTHWEST FLOW WILL ALSO
CONTINUE INTO THE EXTENDED PERIOD AND MODELS LOOK OK HERE TOO
UNTIL LATE IN THE WEEK AND THE WEEKEND. ECMWF APPEARS TO BE
STRONGER WITH A MID LEVEL SYSTEM COMING DOWN INTO THE AREA DURING
THE END OF THE PERIOD.
SHORT TERM...TONIGHT THROUGH WEDNESDAY
FRONTAL SYSTEM OVER THE AREA THIS AFTERNOON WILL GRADUALLY WASHOUT
TONIGHT THROUGH TOMORROW AS A STRONGER WEATHER SYSTEM DEVELOPS OUT
IN THE PLAINS. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS
THE ENTIRE CWA THIS EVENING AND THEN IN THE EAST AFTER
MIDNIGHT...WITH CHANCES BACK TO THE WEST. LIGHT SHOWERS ARE
ONGOING BUT REMNANTS OF AN MCS IN IOWA HAVE CONTINUED TO GET
STRONGER IN SOUTH CENTRAL IOWA AND WILL MOVE EAST-SOUTHEAST INTO
THE CWA THIS EVENING AND THROUGH TONIGHT. BELIEVE THIS
LINE/COMPLEX OF STORMS WILL FOLLOW THE STATIONARY BOUNDARY OVER
THE AREA AS IT MOVES EAST-SOUTHEAST. VARIOUS SHORT TERM MODELS
FORECAST THIS AREA OF STORMS EAST AND SOUTHEAST INTO CENTRAL
ILLINOIS THIS EVENING...THEREFORE CONFIDENCE IS HIGH ENOUGH FOR
LIKELY POPS. NO SEVERE IS EXPECTED WITH THESE STORMS...BUT LOCALLY
HEAVY RAINFALL AND DEADLY LIGHTNING WILL BE LIKELY. PCPN WILL
DIMINISH TOMORROW...BUT WITH LOTS OF LOW LEVEL MOISTURE AND A
STATIONARY BOUNDARY IN THE AREA...CANT RULE OUT A CHANCE OF
THUNDERSTORMS SOMEWHERE TOMORROW. PCPN CHANCES WILL CONTINUE AND
INCREASE INTO TOMORROW NIGHT AND TUESDAY AS ANOTHER...STRONGER
FRONT PUSHES INTO AND THROUGH THE AREA. FORECAST FOR THIS FRONT
APPEAR TO BE THAT IT WILL PUSH SHOULD OF THE STATE LATE TUE NIGHT
AND THEN BRING DRIER AND LESS HUMID AIR INTO THE REGION FOR
WEDNESDAY.
APPEARS TEMPS WILL BE QUITE WARM ONE MORE DAY TOMORROW. THEN
ADDITIONAL CLOUD COVER AND PCPN WILL CAUSE TEMPS TO BE SLIGHTLY
COOLER FOR TUESDAY. MUCH COOLER TEMPS ARE THEN EXPECTED AFTER THE
FRONT MOVES THROUGH THE AREA FOR WEDNESDAY.
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
DRY WEATHER WILL CONTINUE THROUGH THUR NIGHT AS NORTHWEST FLOW
WILL CONTINUE ACROSS THE AREA. A STRONGER SYSTEM/SHORT WAVE TROUGH
WILL THEN DEVELOP AND MOVE TOWARD THE AREA FOR LATE IN THE WEEK.
ECMWF IS STRONGER AND LOOKS MORE CONSISTENT FROM PREVIOUS RUNS WITH
THIS NEXT SYSTEM...THAN THE GFS. LEANING TOWARD THE ECMWF MODEL
GIVES A FORECAST OF PCPN CHANCES FOR FRIDAY THROUGH SATURDAY
NIGHT...SOMEWHERE IN THE CWA...THEN DRY WEATHER POSSIBLE SUNDAY.
STILL LOTS OF UNCERTAINTY WITH THIS PERIOD OF THE FORECAST SO
WOULD NOT BE SURPRISED TO SEE CHANGES TO IT OVER THE NEXT SEVERAL
DAYS.
TEMPS SHOULD BE COOLER THAN LAST WEEK GIVEN THE NORTHWEST FLOW AND
WENT COOLER THAN GUIDANCE FOR SAT AND SUNDAY.
&&
.AVIATION...
ISSUED 700 PM CDT SUN JUL 21 2013
LEANED ON THE HRRR MODEL FOR QPF FIELDS WITH ARRIVAL OF SHOWERS
AND THUNDERSTORMS FROM WEST TO EAST DURING THIS EVENING AND
DIMINISHING OVERNIGHT. HAVE MVFR CEILINGS POSSIBLE TONIGHT WITH
PRECIPITATION ALONG WITH VSBYS RESTRICTED DOWN TO 1.5-3 MILES IN
HEAVIER RAIN SHOWERS. SHOWERS AND A FEW THUNDERSTORMS ARE WEST OF
I-55 AND TO SPREAD EAST TO DEC AND CMI IN THE NEXT FEW
HOURS...THEN DIMINISH FROM WEST TO EAST FROM 05Z-08Z. SOME FOG
POSSIBLE OVERNIGHT INTO MON MORNING WITH VSBYS 2-4 MILES AND THEN
LIFTING TO LIGHT FOG/HAZE OF 4-6 MILES BETWEEN 14-15Z AS MVFR
CEILINGS LIFT TO VFR LATER MON MORNING. SOUTH WINDS TO STAY FAIRLY
LIGHT FROM 4-8 KTS THIS EVENING AND LIGHT AND VARIABLE OVERNIGHT
AND SW 4-7 KTS MONDAY.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
113 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1253 PM CDT SAT JUL 20 2013
OUTFLOW BOUNDARY FROM CONVECTION ACROSS NORTHEAST KANSAS HAS MOVED
INTO AND ACROSS EASTERN SECTION OF CWA...AND IS SPARKING TSRA ACROSS
PORTIONS OF THE EASTERN FLINT HILLS...AS BOUNDARY ENCOUNTERS GREATER
THETAE. FLOW ALOFT IS VERY WEAK...THUS HEALTHY CAPE WILL BE THE ONLY
DRIVER FOR STORM INTENSITY. RUC/HRRR BOTH INDICATE AN INCREASE IN
ISOLD-WDLY SCT CONVECTION THIS AFTERNOON INTO EARLY EVENING...THUS WILL
UPDATE HOURLY POPS TO ACCOUNT. ALSO WILL ADJUST HOURLY
TEMPERATURES AND MAX TEMPERATURES IN EXTREME SOUTHEAST CWA...WHERE
THINGS ARE WARMING MORE THAN ANTICIPATED. NO OTHER CHANGES ATTM.
SF
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1253 PM CDT SAT JUL 20 2013
MAIN CONCERN FOR THE TAF PERIOD WILL BE PERIODS OF ISOLD-SCATTERED CONVECTION.
FORECAST SOUNDINGS INDICATE CONVECTIVE TEMPERATURES WILL BE
REACHED IN THE NEXT HOUR OR TWO...AND WITH SUFFICIENT MID-LEVEL
MOISTURE...ALL TAF SITES SHOULD BEGIN TO SEE TCU/CB DEVELOPMENT
BY 20 UTC. COVERAGE WILL BE LOCALLY DEPENDENT...BUT STARTED WITH
SCT COVERAGE AND INCREASED TO BKN BY 22-23 UTC. CONFIDENCE OF TSRA
OCCURRING AT ANY PARTICULAR TAF SITE IS LOW...THOUGH GREATEST
CHANCES LIKELY AT KICT...KSLN...KCNU AND KHUT DUE TO THEIR PROXIMITY
TO OUTFLOW BOUNDARY THAT HAS MOVED INTO CWA AND IS STALLING. GIVEN CONVECTION
MAINLY WILL BE DIURNALLY DRIVEN...EXPECTED ANY STORMS THAT FIRE
THIS AFTERNOON TO DISSIPATE IN THE 03-04 UTC TIMEFRAME. ANOTHER
ROUND OF CONVECTION WILL BE POSSIBLE AFT 06 UTC...WITH
ENHANCED/FOCUSED ISENTROPIC LIFT THAT WILL BE ENHANCED BY RRQ OF
UPPER JET. REINTRODUCED CONVECTION IN 07-09 UTC TIMEFRAME AS A RESULT.
ISENTROPIC FIELDS LINGER CONVECTION AND CONVECTIVE DEBRIS INTO
SUNDAY MORNING. FORECAST SOUNDINGS PLACING TSRA BASES IN THE 6-8K
AGL RANGE.
SF
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1250 PM CDT SAT JUL 20 2013
...UPDATE TO AVIATION...
.UPDATE...
ISSUED AT 1144 AM CDT SAT JUL 20 2013
WEAK ISENTROPIC LIFT CONTINUES JUST NORTH OF THE FRONTAL BOUNDARY
STRETCHED FROM SALINA TO MANHATTAN...TO OSKALOOSA IN JEFFERSON
COUNTY. ALSO OBSERVING TWO OUTFLOW BOUNDARIES MOVING THROUGH
SOUTHEAST NEBRASKA INTO MARSHALL AND WASHINGTON COUNTIES WHERE
THE ONGOING SHOWERS AND THUNDERSTORMS ARE BEING ABLE TO REDEVELOP
AND MAINTAIN THEMSELVES. CHANGES MADE TO THE CURRENT FORECAST
INCLUDED ADDING PRECIPITATION CHANCES OVER MUCH OF NORTH CENTRAL
AND NORTHEAST KANSAS THROUGH THE AFTERNOON. ALSO ADJUST TEMPERATURES
DOWN SLIGHTLY OVER NORTH CENTRAL/NORTH EAST AREAS WHERE CLOUD
COVER AND RAIN PERSISTS. WILL CONTINUE TO MONITOR FORECAST AS
AREAS OF ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON
ARE DEPENDENT ON LOCATION OF THE FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1238 PM CDT SAT JUL 20 2013
VFR CONDITIONS WILL BE THE PREVAILING CATEGORY AT KTOP/KFOE/KMHK.
CURRENTLY TRACKING A STATIONARY FRONT POSITIONED JUST NORTH OF THE
TERMINALS AT 18Z. SCATTERED TSRA IS POSSIBLE ALONG THIS BOUNDARY
AND WITH SOME UNCERTAINTY AS TO WHERE BOUNDARY WILL INITIATE
STORMS DECIDED TO INSERT VCTS AT SITES AFT 21Z. CONFIDENCE
DECREASES IN PRECIPITATION IMPACTING TERMINALS OVERNIGHT AS ANOTHER
WAVE SHIFTS SOUTHEAST INTO NORTHEAST KANSAS. SHOULD SEE MOSTLY
RAIN SHOWERS WITH THUNDERSTORMS EMBEDDED AFT 07Z AT KMHK AND 08Z
AT KTOP/KFOE. EXACT TIMING OF THESE STORMS MAY NEED TO BE REFINED
AS THEY EVOLVE OVER SOUTHERN NEBRASKA. STORMS WILL BE ELEVATED WITH
PERHAPS A BRIEF PERIOD OF MVFR UNDERNEATH ANY HEAVIER THUNDERSTORM.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BOWEN
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1158 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1144 AM CDT SAT JUL 20 2013
WEAK ISENTROPIC LIFT CONTINUES JUST NORTH OF THE FRONTAL BOUNDARY
STRETCHED FROM SALINA TO MANHATTAN...TO OSKALOOSA IN JEFFERSON
COUNTY. ALSO OBSERVING TWO OUTFLOW BOUNDARIES MOVING THROUGH
SOUTHEAST NEBRASKA INTO MARSHALL AND WASHINGTON COUNTIES WHERE
THE ONGOING SHOWERS AND THUNDERSTORMS ARE BEING ABLE TO REDEVELOP
AND MAINTAIN THEMSELVES. CHANGES MADE TO THE CURRENT FORECAST
INCLUDED ADDING PRECIPITATION CHANCES OVER MUCH OF NORTH CENTRAL
AND NORTHEAST KANSAS THROUGH THE AFTERNOON. ALSO ADJUST TEMPERATURES
DOWN SLIGHTLY OVER NORTH CENTRAL/NORTH EAST AREAS WHERE CLOUD
COVER AND RAIN PERSISTS. WILL CONTINUE TO MONITOR FORECAST AS
AREAS OF ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON
ARE DEPENDENT ON LOCATION OF THE FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 602 AM CDT SAT JUL 20 2013
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS
THE TAF SITES THROUGH 15Z. OTHERWISE...EXPECT VFR CONDITIONS FOR THE
LATE MORNING AND EARLY AFTERNOON. THERE WILL BE ANOTHER CHANCE FOR
SCATTERED THUNDERSTORMS LATE THIS AFTERNOON THROUGH THE MID
EVENING HOURS. LATE IN THE TAF PERIOD THERE COULD BE ANOTHER
CHANCE OF THUNDERSTORMS BUT DUE TO TIMING ISSUES I HAVE NOT
INCLUDED A VCTS GROUP FOR STORMS THAT MAY ARRIVE AROUND SUNRISE ON
SUNDAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BOWEN
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS WICHITA KS
1008 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1001 AM CDT SAT JUL 20 2013
ISOLATED SHRA/TSRA HAVE DISSIPATED FOR THE MOST PART...THOUGH A ANOTHER
POCKET BUMBLING UP ACROSS THE NORTHEAST FRINGES OF FLINT HILLS. TRENDED
POPS DOWN...AND TRIED TO ACCOUNT FOR ADVECTION AS WELL. HOURLY
TEMPERATURE TRENDS ALSO ON TRACK MORE OR LESS...BUT HAD TO ADJUST DEWPOINTS
SLIGHTLY UP IN SOME LOCATIONS AND DOWN IN OTHERS. OTHERWISE MAX
TEMP AND OTHER SENSIBLE WEATHER FORECASTS LOOK ON TRACK.
SF
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 628 AM CDT SAT JUL 20 2013
ISOLATED SHOWERS WERE ONGOING ACROSS MAINLY CENTRAL KANSAS
IMPACTING KRSL AND KSLN. THIS ACTIVTY IS EXPECTED TO DRIFT NORTH
AND DIMINISH BY AROUND 14Z. WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE AREA THIS
AFTERNOON AND FESTER INTO THE OVERNIGHT HOURS. TRANSIENT MVFR WILL
REMAIN POSSIBLE UNDER THE HEAVIER ACTIVITY WHILE VFR PREVAILS
ACROSS THE FORECAST AREA. LIGHT AND VARIABLE WINDS WILL BECOME
SOUTH TO SOUTHEAST BY MID-MORNING AT SPEEDS AROUND 15 MPH
ANTICIPATED.
MWM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
631 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 628 AM CDT SAT JUL 20 2013
ISOLATED SHOWERS WERE ONGOING ACROSS MAINLY CENTRAL KANSAS
IMPACTING KRSL AND KSLN. THIS ACTIVTY IS EXPECTED TO DRIFT NORTH
AND DIMINISH BY AROUND 14Z. WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE AREA THIS
AFTERNOON AND FESTER INTO THE OVERNIGHT HOURS. TRANSIENT MVFR WILL
REMAIN POSSIBLE UNDER THE HEAVIER ACTIVITY WHILE VFR PREVAILS
ACROSS THE FORECAST AREA. LIGHT AND VARIABLE WINDS WILL BECOME
SOUTH TO SOUTHEAST BY MID-MORNING AT SPEEDS AROUND 15 MPH
ANTICIPATED.
MWM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
606 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 602 AM CDT SAT JUL 20 2013
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS
THE TAF SITES THROUGH 15Z. OTHERWISE...EXPECT VFR CONDITIONS FOR THE
LATE MORNING AND EARLY AFTERNOON. THERE WILL BE ANOTHER CHANCE FOR
SCATTERED THUNDERSTORMS LATE THIS AFTERNOON THROUGH THE MID
EVENING HOURS. LATE IN THE TAF PERIOD THERE COULD BE ANOTHER
CHANCE OF THUNDERSTORMS BUT DUE TO TIMING ISSUES I HAVE NOT
INCLUDED A VCTS GROUP FOR STORMS THAT MAY ARRIVE AROUND SUNRISE ON
SUNDAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
352 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1154 PM CDT FRI JUL 19 2013
FOR THE 06Z TAFS...THE SCATTERED SHOWERS AND THUNDERSTORMS FROM THIS
EVENING WILL CONTINUE TO WEAKEN AND DIMINISH INTO THE EARLY
OVERNIGHT HOURS. WINDS OVERNIGHT WILL BE CALM...BECOMING LIGHT OUT
OF THE SOUTHEAST THROUGH THE DAY ON SATURDAY. ADDITIONAL CHANCES
FOR SCATTERED SHOWERS AND THUNDERSTORMS EXISTS ACROSS THE REGION
SATURDAY NIGHT. THERE IS STILL UNCERTAINTY IN THE EXACT TIMING AND
LOCATION OF ANY PRECIPITATION...SO HAVE JUST ADDED THE MENTION OF
VCTS ATTM AND WILL CONTINUE TO ADJUST WITH FUTURE UPDATES.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS WICHITA KS
350 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1139 PM CDT FRI JUL 19 2013
SCATTERED SHOWERS AND THUNDERSTORMS ARE DIMINISHING AS WE APPROACH
06Z. EXPECT ACTIVITY TO WANE THROUGH 12Z AND INTO THE
MORNING/EARLY AFTERNOON HOURS BEFORE ANOTHER ROUND OF SHOWER AND
THUNDERSTORM ACTIVITY IS POSSIBLE IN THE AFTERNOON. CANNOT RULE
OUT SOMETHING IN THE MORNING...BUT DO NOT HAVE IT REPRESENTED IN
THE TAF FORECAST AT THIS TIME. WINDS BEHIND THE CONVECTION ARE
LIGHT AND OUT OF THE EAST. WINDS WILL GRADUALLY BECOME SOUTHERLY
BY MORNING ACROSS THE AREA AND INCREASE SLIGHTLY DURING THE DAY.
VFR CONDITIONS ARE EXPECTED TO PREVAIL.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
933 PM EDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 932 PM EDT SUN JUL 21 2013
TRAINING STORMS WERE STILL ONGOING OVER THE NORTHERN SECTION OF THE
CWA AS WAS DISCUSSED IN THE PREVIOUS UPDATE. WENT AHEAD AND EXTENDED SCT
POPS FOR THE NEXT COUPLE OF HOURS...MAINLY ALONG THE MOUNTAIN PARKWAY
WHERE MAIN SHOWER ACTIVITY HAS BEEN LOCATED. LATEST RADAR TRENDS ARE
SHOWING BEST SHOWER ACTIVITY DIMINISHING...BUT LOW END CHANCE POPS
ARE STILL WARRANTED FOR ONGOING ACTIVITY AND POTENTIAL REDEVELOPMENT.
EXCESS MOISTURE ACROSS THE NORTH AND EAST HAS LED TO FOG DEVELOPMENT
AT THE NWS OFFICE. AS RAIN CONTINUES TO DIMINISH...EXPECT FOG TO
PREVAIL THROUGH MUCH OF THE NIGHT BEFORE NEXT AREA OF WIDESPREAD
SHOWERS AND THUNDERSTORMS MOVES IN BY EARLY MORNING. MADE THIS UPDATE
TO THE WEATHER GRIDS AS WELL...ADDING FOG IN FOR VALLEYS MAINLY IN
THE EASTERN CWA.
UPDATE ISSUED AT 544 PM EDT SUN JUL 21 2013
A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN
HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS
FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS
BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND
THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS.
ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY
BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT
FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS
WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 325 PM EDT SUN JUL 21 2013
MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT
THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS
PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH
THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN
KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET
MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE
APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS
IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC
FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW
MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST.
GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE
SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH
FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN
ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE
POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH
PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM
COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST
ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE
NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE
THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING
UP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 325 PM EDT SUN JUL 21 2013
THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL
TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED.
HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND
TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA
LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF
THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS
FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE
HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH
EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO
CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON
SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE
CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS
FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG.
IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM
SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A
DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL
PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF
SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND
UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS
WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL.
A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER
THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE
MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR
WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF
AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS
HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW
PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO
KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND
THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT
COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH
ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE
COOLER AIR REMAINS TO START THE NEW WORK WEEK.
THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN
THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM
THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF.
ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY
NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 754 PM EDT SUN JUL 21 2013
VERY TRICKY AVIATION FORECAST...WITH MANY THINGS TO CONSIDER OVER THE
NEXT 24 HOURS. A FRONTAL BOUNDARY DRAPED ACROSS THE AREA WILL
CONTINUE TO PRODUCE TRAINING SHOWERS AND THUNDERSTORMS ACROSS THE
NORTHERN HALF OF THE CWA...INCLUDING KJKL. KJKL IS CURRENTLY
EXPERIENCING HEAVY RAIN...BR...AND LIFR VIS AT TIMES. EXPECT THESE
SHOWERS AND RESULTING CONDITIONS TO CONTINUE ALONG THE BOUNDARY OVER
THE NEXT COUPLE OF HOURS. ELSEWHERE...SHOWER ACTIVITY AND BKN CLOUDS
ARE TRYING TO CLEAR...BUT LEFT MVFR BKN IN THE TAFS FOR KLOZ AND
KSME SINCE SOME HEAVIER BKN BANDS OF CLOUDS ARE STILL POSSIBLE
ACCORDING TO LATEST SATELLITE. FOR THE REST OF THE NIGHT...ANY
LINGERING SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF BY LATE
TONIGHT...BUT WITH CLEARING COMES THE POSSIBILITY FOR FOG TO
DEVELOP. TRIED TO BE OPTIMISTIC ON VALLEY FOG REACHING TAF
SITES...ONLY GOING MVFR VIS...BUT MAY NEED TO ADJUST AS FOG
DEVELOPS. THE NEXT CHANCE FOR WIDESPREAD RAIN AND THUNDERSTORMS WILL
MOVE IN BY DAWN AND CONTINUE THROUGHOUT THE DAY AT ALL TAF SITES.
STILL SOMEWHAT UNCERTAIN ON VIS AND CIG RESTRICTIONS DURING THIS TIME
WITH ONGOING CONVECTIVE ACTIVITY...BUT TRIED TO SHOW GENERAL TREND
DOWNWARDS. VIS WILL BE RESTRICTED FURTHER IF A HEAVY RAIN SHOWER
PASSES OVER TAF SITE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
754 PM EDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 544 PM EDT SUN JUL 21 2013
A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN
HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS
FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS
BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND
THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS.
ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY
BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT
FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS
WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 325 PM EDT SUN JUL 21 2013
MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT
THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS
PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH
THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN
KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET
MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE
APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS
IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC
FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW
MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST.
GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE
SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH
FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN
ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE
POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH
PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM
COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST
ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE
NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE
THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING
UP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 325 PM EDT SUN JUL 21 2013
THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL
TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED.
HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND
TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA
LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF
THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS
FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE
HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH
EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO
CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON
SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE
CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS
FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG.
IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM
SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A
DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL
PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF
SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND
UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS
WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL.
A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER
THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE
MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR
WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF
AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS
HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW
PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO
KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND
THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT
COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH
ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE
COOLER AIR REMAINS TO START THE NEW WORK WEEK.
THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN
THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM
THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF.
ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY
NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 754 PM EDT SUN JUL 21 2013
VERY TRICKY AVIATION FORECAST...WITH MANY THINGS TO CONSIDER OVER THE
NEXT 24 HOURS. A FRONTAL BOUNDARY DRAPED ACROSS THE AREA WILL
CONTINUE TO PRODUCE TRAINING SHOWERS AND THUNDERSTORMS ACROSS THE
NORTHERN HALF OF THE CWA...INCLUDING KJKL. KJKL IS CURRENTLY
EXPERIENCING HEAVY RAIN...BR...AND LIFR VIS AT TIMES. EXPECT THESE
SHOWERS AND RESULTING CONDITIONS TO CONTINUE ALONG THE BOUNDARY OVER
THE NEXT COUPLE OF HOURS. ELSEWHERE...SHOWER ACTIVITY AND BKN CLOUDS
ARE TRYING TO CLEAR...BUT LEFT MVFR BKN IN THE TAFS FOR KLOZ AND
KSME SINCE SOME HEAVIER BKN BANDS OF CLOUDS ARE STILL POSSIBLE
ACCORDING TO LATEST SATELLITE. FOR THE REST OF THE NIGHT...ANY
LINGERING SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF BY LATE
TONIGHT...BUT WITH CLEARING COMES THE POSSIBILITY FOR FOG TO
DEVELOP. TRIED TO BE OPTIMISTIC ON VALLEY FOG REACHING TAF
SITES...ONLY GOING MVFR VIS...BUT MAY NEED TO ADJUST AS FOG
DEVELOPS. THE NEXT CHANCE FOR WIDESPREAD RAIN AND THUNDERSTORMS WILL
MOVE IN BY DAWN AND CONTINUE THROUGHOUT THE DAY AT ALL TAF SITES.
STILL SOMEWHAT UNCERTAIN ON VIS AND CIG RESTRICTIONS DURING THIS TIME
WITH ONGOING CONVECTIVE ACTIVITY...BUT TRIED TO SHOW GENERAL TREND
DOWNWARDS. VIS WILL BE RESTRICTED FURTHER IF A HEAVY RAIN SHOWER
PASSES OVER TAF SITE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
528 PM EDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 527 PM EDT SAT JUL 20 2013
BASED ON CURRENT RADAR TRENDS...DIDN/T FEEL CONFIDENT IN NO POPS
ACROSS THE AREA THIS AFTERNOON/EVENING. WENT AHEAD AND ADDED IN SOME
SLIGHT CHANCES ALONG THE NORTHERN AND SOUTHEASTERN SECTIONS OF THE
CWA THROUGH THIS AFTERNOON IN CASE SOME SHORT LIVED CONVECTION
DEVELOPS. THEN HAVE ISOLATED CHANCES TAPERING OFF ACROSS THE
SOUTHEAST THIS EVENING AS BEST INSTABILITY BECOMES FOCUSED OVER THE
NORTHERN CWA WITH AN IMPOSING COLD FRONT AND AREA OF CONVECTION
MOVING INTO THE REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 325 PM EDT SAT JUL 20 2013
CONTINUING TO WATCH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DROPPING SOUTHWARD ACROSS THE OHIO RIVER VALLEY. A GAP IN THE LINE
HAS OPENED UP JUST TO OUR NORTH. WHILE SHOWERS AND STORMS ARE STILL
POSSIBLE THIS EVENING INTO TONIGHT...EVERY HRRR RUN OVER THE PAST
SEVERAL HOURS CONTINUES TO BACK OFF ON OVERALL COVERAGE ACROSS
EASTERN KENTUCKY THIS EVENING...WITH EVERYTHING FADING AWAY AROUND
SUNSET. THUS...HAVE DECREASED POPS INTO THIS EVENING AND THE
OVERNIGHT HOURS. THIS TREND MAY HAVE TO BE CONTINUED ON THE EVENING
SHIFT IF THE TRENDS CONTINUE THE WAY THEY ARE HEADING.
REGARDLESS...THE PROSPECTS FOR WIDESPREAD SHOWERS AND THUNDERSTORMS
IS DRASTICALLY LESS NOW. WILL MAINTAIN LOW 20-30 POPS THROUGH THE
OVERNIGHT HOURS. WITH THE BOUNDARY WASHED OUT OVER THE AREA
TOMORROW...DAYTIME HEATING SHOULD ALLOW FOR QUICK REDEVELOPMENT AFTER
SUNRISE. COVERAGE SHOULD BE DECENT TOMORROW...SO OPTED TO STAY WITH
OUR 60-70 POPS. THERE IS SOME QUESTION AS TO HOW MUCH ACTIVITY WILL
THEN LINGER INTO TOMORROW NIGHT AS THE QUASI BOUNDARY MAY SHIFT BACK
TO THE NORTH. LACK OF OVERNIGHT INSTABILITY MAY KEEP THINGS FAIRLY
LOW KEY FOR MUCH OF THE NIGHT. THERE IS A SHORTWAVE TROUGH PUSHING
ACROSS THE AREA LATE IN THE NIGHT THAT COULD ACT TO FIRE OFF SOME
SHOWERS AND THUNDERSTORMS...SO WILL INCREASE POPS THROUGH THE NIGHT.
TEMPERATURES ON SUNDAY SHOULD BE SLIGHTLY LOWER WITH THE INCREASED
CLOUD COVER AND PRECIPITATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 325 PM EDT SAT JUL 20 2013
THE MODELS BASICALLY AGREE ON THE GENERAL MID LEVEL PATTERN THROUGH
THE BULK OF THE EXTENDED FORECAST. A TROUGH WILL DEVELOP THROUGH THE
OHIO VALLEY INITIALLY AS ENERGY FROM THE NORTHERN PLAINS POOLS OVER
THE REGION. THIS TROUGH EVOLVES GRADUALLY AS A COUPLE OF CYCLES
OF WAVES MOVE THROUGH THE OHIO VALLEY...EACH DEPICTED SLIGHTLY
DIFFERENT BY THE MODELS. THIS SEMI-STATIONARY TROUGH BOTTOMS OUT ON
THURSDAY PER A CONSENSUS OF SOLUTIONS. EACH MODEL HAS ENOUGH OF A
DIFFERENT HANDLING OF THE INDIVIDUAL WAVES THAT A BLENDED APPROACH
IS PREFERRED FOR EXTENDED FORECASTING PURPOSES. IT DOES LOOK LIKE
HEIGHTS WILL RISE A BIT ON FRIDAY AS THE CORE OF THE TROUGH SHIFTS
TEMPORARILY EAST BUT THE ECMWF IS MOST AGGRESSIVE IN TAKING ANOTHER
DECENT WAVE FROM THE PLAINS EAST INTO THE OHIO VALLEY FOR THE
WEEKEND LIKELY RESTORING THE TROUGH FOR THE OHIO VALLEY. THE GFS HAS
A VERSION OF THIS THAT ALSO LOWERS HEIGHTS OVER THE OHIO VALLEY ON
SATURDAY...BUT DOES SO BY RELYING ON WAVES FURTHER NORTH THAN THE
ECMWF...MAINLY MOVING THEM THROUGH THE GREAT LAKES. AGAIN HERE...
WILL FAVOR A CONSENSUS SOLUTION FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A VERY UNSETTLED SITUATION TO START
THE EXTENDED AS MID LEVEL WAVES ACTIVATE SHOWERS AND THUNDERSTORMS
ALONG AND SOUTH OF A FRONTAL BOUNDARY RUNNING JUST NORTH OF THE OHIO
RIVER. THERE WILL BE PLENTY OF HIGH PW AIR IN PLACE TO SUPPORT THE
STORMS AND THUS A HEAVY RAIN POTENTIAL WILL EXIST THROUGH THE
DAY...MONDAY. THE NEXT SFC BOUNDARY WILL APPROACH THE AREA ON
TUESDAY CONTINUING OUR CHANCES OF SHOWERS AND THUNDERSTORMS. THIS
CONVECTION IS EXPECTED TO LINGER INTO THE NIGHT WHEN THE BOUNDARY
DROPS THROUGH THE CWA IN THE FORM OF A COLD FRONT. FOR THURSDAY AND
FRIDAY...ANY CONVECTION SHOULD BE AT A MINIMUM IN THE WAKE OF THE
SFC FRONT AND SLIGHTLY HIGHER HEIGHTS ALOFT. HOWEVER...THE NEXT SFC
SYSTEM LOOKS TO BRING A RENEWED CHANCE OF CONVECTION TO THE AREA ON
SATURDAY...SPURRED ON BY FALLING HEIGHTS AND MORE INBOUND MID-LEVEL
ENERGY.
THE CR GRID LOAD CAME IN PRETTY GOOD CONSIDERING THE SMALLER SCALE
DIFFERENCES AMONG THE MODELS WITH RESPECT TO WEATHER DETAILS THROUGH
THE EXTENDED. DID NUDGE DOWN POPS A BIT LATE IN THE FORECAST...MORE
TOWARD THE OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD
FOR WEDNESDAY AND THURSDAY NIGHT TO BETTER EMPHASIZE RIDGE AND
VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY
THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH
SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT
THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT
THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS
THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS
WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD
INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW
CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO
MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL
CONTINUE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
325 PM EDT SAT JUL 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 325 PM EDT SAT JUL 20 2013
CONTINUING TO WATCH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DROPPING SOUTHWARD ACROSS THE OHIO RIVER VALLEY. A GAP IN THE LINE
HAS OPENED UP JUST TO OUR NORTH. WHILE SHOWERS AND STORMS ARE STILL
POSSIBLE THIS EVENING INTO TONIGHT...EVERY HRRR RUN OVER THE PAST
SEVERAL HOURS CONTINUES TO BACK OFF ON OVERALL COVERAGE ACROSS
EASTERN KENTUCKY THIS EVENING...WITH EVERYTHING FADING AWAY AROUND
SUNSET. THUS...HAVE DECREASED POPS INTO THIS EVENING AND THE
OVERNIGHT HOURS. THIS TREND MAY HAVE TO BE CONTINUED ON THE EVENING
SHIFT IF THE TRENDS CONTINUE THE WAY THEY ARE HEADING.
REGARDLESS...THE PROSPECTS FOR WIDESPREAD SHOWERS AND THUNDERSTORMS
IS DRASTICALLY LESS NOW. WILL MAINTAIN LOW 20-30 POPS THROUGH THE
OVERNIGHT HOURS. WITH THE BOUNDARY WASHED OUT OVER THE AREA
TOMORROW...DAYTIME HEATING SHOULD ALLOW FOR QUICK REDEVELOPMENT AFTER
SUNRISE. COVERAGE SHOULD BE DECENT TOMORROW...SO OPTED TO STAY WITH
OUR 60-70 POPS. THERE IS SOME QUESTION AS TO HOW MUCH ACTIVITY WILL
THEN LINGER INTO TOMORROW NIGHT AS THE QUASI BOUNDARY MAY SHIFT BACK
TO THE NORTH. LACK OF OVERNIGHT INSTABILITY MAY KEEP THINGS FAIRLY
LOW KEY FOR MUCH OF THE NIGHT. THERE IS A SHORTWAVE TROUGH PUSHING
ACROSS THE AREA LATE IN THE NIGHT THAT COULD ACT TO FIRE OFF SOME
SHOWERS AND THUNDERSTORMS...SO WILL INCREASE POPS THROUGH THE NIGHT.
TEMPERATURES ON SUNDAY SHOULD BE SLIGHTLY LOWER WITH THE INCREASED
CLOUD COVER AND PRECIPITATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 325 PM EDT SAT JUL 20 2013
THE MODELS BASICALLY AGREE ON THE GENERAL MID LEVEL PATTERN THROUGH
THE BULK OF THE EXTENDED FORECAST. A TROUGH WILL DEVELOP THROUGH THE
OHIO VALLEY INITIALLY AS ENERGY FROM THE NORTHERN PLAINS POOLS OVER
THE REGION. THIS TROUGH EVOLVES GRADUALLY AS A COUPLE OF CYCLES
OF WAVES MOVE THROUGH THE OHIO VALLEY...EACH DEPICTED SLIGHTLY
DIFFERENT BY THE MODELS. THIS SEMI-STATIONARY TROUGH BOTTOMS OUT ON
THURSDAY PER A CONSENSUS OF SOLUTIONS. EACH MODEL HAS ENOUGH OF A
DIFFERENT HANDLING OF THE INDIVIDUAL WAVES THAT A BLENDED APPROACH
IS PREFERRED FOR EXTENDED FORECASTING PURPOSES. IT DOES LOOK LIKE
HEIGHTS WILL RISE A BIT ON FRIDAY AS THE CORE OF THE TROUGH SHIFTS
TEMPORARILY EAST BUT THE ECMWF IS MOST AGGRESSIVE IN TAKING ANOTHER
DECENT WAVE FROM THE PLAINS EAST INTO THE OHIO VALLEY FOR THE
WEEKEND LIKELY RESTORING THE TROUGH FOR THE OHIO VALLEY. THE GFS HAS
A VERSION OF THIS THAT ALSO LOWERS HEIGHTS OVER THE OHIO VALLEY ON
SATURDAY...BUT DOES SO BY RELYING ON WAVES FURTHER NORTH THAN THE
ECMWF...MAINLY MOVING THEM THROUGH THE GREAT LAKES. AGAIN HERE...
WILL FAVOR A CONSENSUS SOLUTION FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A VERY UNSETTLED SITUATION TO START
THE EXTENDED AS MID LEVEL WAVES ACTIVATE SHOWERS AND THUNDERSTORMS
ALONG AND SOUTH OF A FRONTAL BOUNDARY RUNNING JUST NORTH OF THE OHIO
RIVER. THERE WILL BE PLENTY OF HIGH PW AIR IN PLACE TO SUPPORT THE
STORMS AND THUS A HEAVY RAIN POTENTIAL WILL EXIST THROUGH THE
DAY...MONDAY. THE NEXT SFC BOUNDARY WILL APPROACH THE AREA ON
TUESDAY CONTINUING OUR CHANCES OF SHOWERS AND THUNDERSTORMS. THIS
CONVECTION IS EXPECTED TO LINGER INTO THE NIGHT WHEN THE BOUNDARY
DROPS THROUGH THE CWA IN THE FORM OF A COLD FRONT. FOR THURSDAY AND
FRIDAY...ANY CONVECTION SHOULD BE AT A MINIMUM IN THE WAKE OF THE
SFC FRONT AND SLIGHTLY HIGHER HEIGHTS ALOFT. HOWEVER...THE NEXT SFC
SYSTEM LOOKS TO BRING A RENEWED CHANCE OF CONVECTION TO THE AREA ON
SATURDAY...SPURRED ON BY FALLING HEIGHTS AND MORE INBOUND MID-LEVEL
ENERGY.
THE CR GRID LOAD CAME IN PRETTY GOOD CONSIDERING THE SMALLER SCALE
DIFFERENCES AMONG THE MODELS WITH RESPECT TO WEATHER DETAILS THROUGH
THE EXTENDED. DID NUDGE DOWN POPS A BIT LATE IN THE FORECAST...MORE
TOWARD THE OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD
FOR WEDNESDAY AND THURSDAY NIGHT TO BETTER EMPHASIZE RIDGE AND
VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY
THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH
SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT
THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT
THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS
THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS
WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD
INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW
CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO
MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL
CONTINUE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
200 PM CDT SAT JUL 20 2013
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 200 PM CDT SAT JUL 20 2013
18Z MESOANALYSIS SHOWS A COLD FRONT EXTENDING WESTWARD ACROSS
CENTRAL INDIANA TO A WEAK SURFACE LOW OVER CENTRAL ILLINOIS. A
SURFACE TROUGH EXTENDS SOUTHWEST FROM THE LOW CENTER TO NEAR KFAM
AND THEN BETWEEN KUNO/KPOF. DEW POINTS POOLING INTO THE LOWER AND
MID 70S ALONG THE TROUGH AND COLD FRONT HAVE CONTRIBUTED TO VERY
UNSTABLE CAPES LOCALLY OVER 3000 J/KG. ISOLATED STORMS HAVE POPPED
UP ALONG THE SURFACE TROUGH OVER MISSOURI...WHILE LARGER CLUSTERS OF
STORMS ARE EAST OF THE SURFACE LOW CENTER IN INDIANA/EAST CENTRAL IL.
THROUGH THE EVENING HOURS...THE COLD FRONT IS FORECAST TO DRIFT
SOUTH TO THE INTERSTATE 64 CORRIDOR WHILE THE SURFACE TROUGH REMAINS
STATIONARY OVER THE MISSOURI OZARKS. THE LATEST HRRR MODEL
REFLECTIVITY INDICATES THAT CLUSTERS OF STORMS /POSSIBLE MCS/ WILL
PROPAGATE SOUTH ALONG THE WABASH VALLEY...REACHING THE PENNYRILE
REGION OF WESTERN KY THIS EVENING. THIS SCENARIO IS SUPPORTED BY THE
12Z HIGH RES NMM. OTHER ISOLATED STORMS MAY DEVELOP EASTWARD FROM
THE SURFACE TROUGH OVER MISSOURI. VERY LIMITED SHEAR MAGNITUDE WILL
LIMIT SEVERE POTENTIAL TO ISOLATED PULSE EVENTS...THOUGH AN
ORGANIZED COLD POOL COULD DEVELOP WITH THE WABASH VALLEY MCS.
ACTIVITY WILL WEAKEN SIGNIFICANTLY BY 06Z AS THE BOUNDARY LAYER
COOLS AND STABILIZES.
ON SUNDAY...THE SURFACE FRONT IS FORECAST TO SLOWLY LIFT BACK NORTH
AS A WARM FRONT. A MINOR 500 MB SHORTWAVE WILL MOVE EAST/SOUTHEAST
ACROSS THE MISSISSIPPI VALLEY. THIS SHORTWAVE WILL HELP REJUVENATE
CONVECTION ALONG AND SOUTH OF THE FRONT...ESPECIALLY DURING THE
WARMER AND MORE UNSTABLE AFTERNOON HOURS. HIGH TEMPS WILL STRUGGLE
TO REACH THE UPPER 80S DUE TO ABUNDANT CLOUDINESS AND CONVECTION.
ON SUNDAY NIGHT...A RATHER WELL DEVELOPED 500 MB SHORTWAVE FOR MID
SUMMER WILL APPROACH FROM THE CENTRAL PLAINS. THIS SHORTWAVE WILL
TAP A VERY MOIST AND UNSTABLE SOUTHWEST WIND FLOW. SHOWERS AND
STORMS ARE LIKELY OVERNIGHT INTO MONDAY MORNING...UNTIL THE PASSAGE
OF THE SHORTWAVE. ONCE AGAIN...SEASONABLY WEAK SHEAR PROFILES WILL
LIMIT THE POTENTIAL HAZARDS TO MAINLY HEAVY RAIN AND FREQUENT
LIGHTNING.
ON MONDAY AFTERNOON AND MONDAY NIGHT...PRECIP COVERAGE WILL
GRADUALLY DECREASE WITH THE PASSAGE OF THE SHORTWAVE. 850 MB WARM
ADVECTION WILL BE COUNTERED BY EXTENSIVE CLOUD COVER AND PRECIP...
SO DAYTIME HIGHS ON MONDAY WILL ONLY BE NEAR SEASONAL NORMS.
OVERNIGHT LOWS WILL BE NEAR SURFACE DEW POINTS IN THE LOWER 70S.
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 200 PM CDT SAT JUL 20 2013
THE MODELS ARE IN A LITTLE BETTER AGREEMENT WITH THE TIMING OF THE
MID WEEK FRONT. THIS FRONT WILL PROVIDE THE FOCUS FOR THUNDERSTORMS
TUESDAY THEN TAPERING OFF INTO WEDNESDAY. WEAK HIGH PRESSURE WILL
DRY US OUT FOR AT LEAST THURSDAY AND FRIDAY WITH AT LEAST A CHANCE
RETURNING FRIDAY NIGHT INTO SATURDAY AS YET ANOTHER COLD FRONT
ENTERS THE PICTURE AT THE SAME TIME A WARM FRONT TRIES TO LIFT OUT
OF THE PLAINS INTO THE REGION. THE LATEST RUNS WOULD HAVE THE COLD
FRONT WINNING OUT AND SUPPRESSING THE WARM FRONT TO THE SOUTHWEST.
HOWEVER...THE SIGNALS ARE VERY WEAK AND MAY FLIP FLOP WITH LATER
RUNS. THIS WOULD ALSO RESULT IN A SIGNIFICANT CHANGE FOR TEMPS THIS
WEEKEND. EITHER WAY ONE SYSTEM OR THE OTHER WILL PROVIDE A CHANCE
FOR THUNDERSTORMS.
AS FOR TEMPS FOLLOWED THE ONGOING TREND WITH THE WARMEST DAY TUESDAY
THEN COOLING AND A BIT DRIER LATE IN THE WEEK. TEMPS BEGIN TO SOAR
BACK TO AROUND 90 LATE IN THE WEEK AHEAD OF THE APPROACHING COLD
FRONT. IF THE WEEKEND COLD FRONT MAKES IT THROUGH THE AREA WE WILL
COOL BACK INTO THE 80S AGAIN HOWEVER SHOULD THE WARM FRONT OVERTAKE
THE REGION WILL HAVE TO ADJUST TEMPS UP FROM CURRENT FORECAST.
&&
.AVIATION...
ISSUED AT 1226 PM CDT SAT JUL 20 2013
A WEAK COLD FRONT WAS IN THE VICINITY OF KSTL/KIND LINE AT 17Z. THIS
FRONT WILL SINK SLOWLY SOUTH...POSSIBLY BRINGING ISOLATED TO
SCATTERED THUNDERSTORMS TO THE TAF SITES THIS EVENING. CONVECTION
SHOULD WEAKEN OR DISSIPATE WITH LOSS OF DAYTIME HEATING BY 06Z.
WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT...ALLOWING SOME LIGHT
FOG OR HAZE TO FORM AS SKIES BECOME MOSTLY CLEAR. MID LEVEL CLOUDS
WILL INCREASE AHEAD OF AN UPPER LEVEL DISTURBANCE EARLY SUNDAY.
SCATTERED SHOWERS MAY DEVELOP AFTER SUNRISE AS THE FRONT BEGINS TO
MOVE BACK NORTH AS A WARM FRONT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...MY
LONG TERM...KH
AVIATION...MY
AREA FORECAST DISCUSSION
NWS JACKSON KY
123 PM EDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 123 PM EDT SAT JUL 20 2013
WATCHING A COUPLE COMPLEXES OF SHOWERS AND THUNDERSTORMS OFF TO THE
NORTH. THE FIRST ONE JUST WENT THROUGH THE INDIANAPOLIS AREA...WITH
THE SECOND ONE JUST THROUGH DAYTON. THE ONE THAT CONCERNS EASTERN
KENTUCKY IS THE COMPLEX IN INDIANA. BASED ON TRENDS...THIS COMPLEX
SHOULD REACH NORTHERN FLEMING COUNTY AROUND 23Z. THERE WAS A WIND
GUST AT THE INDIANAPOLIS AIRPORT TO 36 KNOTS...SO THERE IS SOME LOW
END POTENTIAL FOR SOME STRONG WIND GUSTS AS THIS STUFF PUSHES
SOUTHEAST THIS EVENING. SPC HAS ISSUED A WATCH JUST TO OUR NORTH.
FORTUNATELY THE SHEAR IS VERY WEAK AND GETTING MORE WIDESPREAD
DAMAGING WINDS SEEMS VERY LOW AT THIS TIME. OTHER ISOLATED SHOWERS
AND EVEN A THUNDERSTORM HAVE DEVELOPED ACROSS EASTERN KENTUCKY. MOST
OF THESE SHOWERS HAVE BEEN SHORT LIVED AND FEW AND FAR BETWEEN.
OUTSIDE OF A SOME SPORADIC LIGHTNING OR A BRIEF PERIOD OF HEAVY
RAIN...THESE SHOWERS SHOULD POSE VERY LITTLE THREAT TO THE AREA THIS
AFTERNOON.
UPDATE ISSUED AT 923 AM EDT SAT JUL 20 2013
BAND OF ENHANCED CU IS PUSHING SOUTHEAST...EXTENDING FROM NEAR
DANVILLE TO WEST LIBERTY THIS MORNING. BASED ON INITIAL ANALYSIS THIS
MORNING...THIS MAY HELP TO GENERATE SOME ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS HEADING INTO THE AFTERNOON HOURS.
HOWEVER...THIS ACTIVITY WILL LIKELY SHIFT SOUTHEAST AS WE HEAD INTO
THE LATE AFTERNOON HOURS AS SUBSIDENCE AHEAD OF THE APPROACHING COLD
FRONT FROM THE NORTH OVERSPREADS THE AREA. LATEST HRRR TAKES MOST OF
THE DAY TO GET ANY PRECIPITATION AS FAR SOUTH AS FLEMING COUNTY
(LIKELY NOT UNTIL AFTER 22 OR 23Z). THUS...GOING TO BACK OFF ON THE
HIGHER PRECIPITATION CHANCES TODAY...BUT STILL CARRY SOME ISOLATED
COVERAGE ACROSS THE SOUTHEAST ASSOCIATED WITH THE BAND OF ENHANCED
CU AS IT DROPS SOUTHEAST. OTHERWISE...WILL GO WITH HIGHER POPS NORTH
OF I-64 AFTER 22Z. SOME QUESTION AS TO HOW MUCH ACTIVITY LINGERS INTO
TONIGHT AS THE FRONT WASHES OUT OVER THE AREA. WILL DROP POPS BACK
FOR THE OVERNIGHT HOURS AS COVERAGE WILL LIKELY REMAIN MORE ISOLATED
TO SCATTERED ALONG THE BOUNDARY SINCE IT WILL BE HARD TO SEE MUCH
ORGANIZED ACTIVITY ALONG THE STALLED BOUNDARY. UPDATE WILL BE OUR
SHORTLY.
UPDATE ISSUED AT 705 AM EDT SAT JUL 20 2013
INGESTED THE MOST CURRENT OBSERVATION DATA TO ESTABLISH NEW TRENDS IN
THE FORECAST GRIDS. THE FORECAST WAS ON TRACK OVERALL...ALTHOUGH THE
FOG THAT WAS FORECAST TO FORM OVERNIGHT WAS NOT NEARLY AS EXTENSIVE
AS ORIGINAL THINKING INDICATED. WITH THE FORECAST IN PRETTY GOOD
SHAPE OVERALL...NO UPDATE IS PLANNED AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL LARGE SCALE
WEATHER PATTERN AND SENSIBLE WEATHER FOR THE NEXT COUPLE OF DAYS. A
WARM AND HUMID AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KENTUCKY
TODAY AND TOMORROW...AS SOUTHERLY FLOW PERSISTS AHEAD OF A SLOWLY
APPROACHING COLD FRONT. THE WEATHER TODAY SHOULD START OUT QUIET...AS
THE LACK OF A GOOD TRIGGER FOR CONVECTION SHOULD KEEP SHOWER AND
STORM ACTIVITY TO A MINIMUM THROUGH EARLY THIS AFTERNOON. SHOWERS AND
STORMS WILL GRADUALLY INCREASE IN COVERAGE BEGINNING MID AFTERNOON
TODAY...AS THE COLD FRONT FINALLY BEGINS MAKING ITS SOUTHWARD PUSH.
THE BEST CHANCE FOR RAIN WILL BEGIN EARLY THIS EVENING NORTH OF THE
MOUNTAIN PARKWAY. THE FRONT IS THEN PROGGED TO SAG SOUTHWARD OUT OF
THE OHIO VALLEY AND ACROSS CENTRAL AND EASTERN KENTUCKY OVERNIGHT
TONIGHT. ONCE LOSS OF DAYTIME HEATING BEGINS TO OCCUR...ANY SHOWERS
AND STORMS WILL DECREASE IN COVERAGE...WITH ONLY SCATTERED SHOWERS
AND ISOLATED STORMS EXPECTED DURING THE NIGHT TIME HOURS. ONCE THE
SUN HAS A BEEN UP FOR AWHILE ON SUNDAY...THE FRONT WILL BECOME ACTIVE
ONCE AGAIN...WITH NUMEROUS SHOWERS AND STORMS EXPECTED ACROSS THE
AREA FROM LATE SUNDAY MORNING THROUGH THE END OF THE DAY ON SUNDAY.
DUE TO SLUGGISH MIDDLE AND UPPER LEVEL WINDS...ANY SHOWERS AND STORMS
THAT FORM WILL BE VERY SLOW MOVING...WHICH COULD LEAD TO LOCALIZED
HEAVY RAIN AND POSSIBLY MINOR FLOODING ISSUES.
TEMPERATURES WILL BE QUITE HOT ONCE AGAIN TODAY...BUT WITH THE GROUND
STILL BEING SOMEWHAT MOIST FROM RECENT RAINFALL...AND WITH AREA
VEGETATION IN FULL LEAF...90 DEGREE READINGS WILL BE DIFFICULT TO
COME BY. WITH THAT IN MIND...LOWERED TODAYS HIGH TEMPERATURES ACROSS
THE BOARD TO REFLECT THIS. WILL LIKELY SEE READINGS TOP OUT MOSTLY IN
THE UPPER 80S AREA WIDE...WITH ISOLATED OCCURRENCES OF 90 HERE AND
THERE. HIGHS ON SUNDAY WILL LIKELY RUN SLIGHTLY BELOW NORMAL...DUE TO
SHOWER AND STORM ACTIVITY AND THE PASSAGE OF THE COLD FRONT. HIGHS ON
SUNDAY ARE EXPECTED TO TOP OUT IN THE LOWER 80S. OVERNIGHT LOWS WILL
BOTTOM OUT AROUND A BALMY 70 DEGREES. WINDS WILL REMAIN FAIRLY LIGHT
ACROSS THE AREA TODAY AND TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
THE SYNOPTIC PATTERN OVER THE EASTERN U.S. NEXT WEEK WILL FEATURE
THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EARLY IN THE WEEK WITH A
LEAD SHORTWAVE TRAVERSING THE OHIO VALLEY MONDAY AND MONDAY NIGHT.
OUR FORECAST WILL FEATURE THE HIGHEST RAIN CHANCES WITH THIS LEAD
SHORTWAVE ACTING AS THE FOCUS FOR SHOWERS AND THUNDERSTORMS MONDAY
AND MONDAY NIGHT. THIS FEATURE WILL PASS BY BUT THE UPPER LEVEL
TROUGH IS PROGGED TO HANG OUT WITH IT/S AXIS ALIGNED DOWN THE
APPALACHIAN CHAIN THROUGH AT LEAST FRIDAY...WITH SIGNS IN THE
MODELING THAT IT WILL GET REINFORCED NEXT WEEKEND. THIS SPELLS A
CONTINUATION OF UNSETTLED WEATHER WITH DAILY SHOWER AND THUNDERSTORM
CHANCES. A COLD FRONT WILL SLOWLY DROP THROUGH THE OHIO VALLEY
MIDWEEK RESULTING IN SCATTERED SHOWERS/STORMS...ESPECIALLY DURING
THE AFTERNOON AND EARLY EVENING HOURS. THE FRONT IS PROGGED TO DROP
TO OUR SOUTH FINALLY BY LATE THURSDAY INTO FRIDAY WITH A WEAK AREA
OF HIGH PRESSURE SLIDING DOWN INTO THE REGION. TRENDED RAIN CHANCES
DOWNWARD FROM INHERITED NUMBERS THURSDAY AND FRIDAY...BUT DID NOT
REMOVE THEM TOTALLY JUST YET.
THE GOOD NEWS IS THAT TEMPERATURES AND DEWPOINTS WILL BE ON A
DOWNWARD TREND DURING THE PERIOD. TEMPS WILL SETTLE BACK TO MORE
NORMAL VALUES FOR THIS TIME OF YEAR...WITH HIGHS GENERALLY IN THE
LOW TO MID 80S EACH DAY. DEWPOINTS WILL REMAIN HIGH...AROUND
70...UNTIL THE COLD FRONT DROPS TO OUR SOUTH LATE IN THE WEEK. THIS
SHOULD DROP DEWS BACK INTO THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY
THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH
SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT
THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT
THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS
THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS
WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD
INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW
CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO
MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL
CONTINUE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...AR
LONG TERM...ABE
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
923 AM EDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 923 AM EDT SAT JUL 20 2013
BAND OF ENHANCED CU IS PUSHING SOUTHEAST...EXTENDING FROM NEAR
DANVILLE TO WEST LIBERTY THIS MORNING. BASED ON INITIAL ANALYSIS THIS
MORNING...THIS MAY HELP TO GENERATE SOME ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS HEADING INTO THE AFTERNOON HOURS.
HOWEVER...THIS ACTIVITY WILL LIKELY SHIFT SOUTHEAST AS WE HEAD INTO
THE LATE AFTERNOON HOURS AS SUBSIDENCE AHEAD OF THE APPROACHING COLD
FRONT FROM THE NORTH OVERSPREADS THE AREA. LATEST HRRR TAKES MOST OF
THE DAY TO GET ANY PRECIPITATION AS FAR SOUTH AS FLEMING COUNTY
(LIKELY NOT UNTIL AFTER 22 OR 23Z). THUS...GOING TO BACK OFF ON THE
HIGHER PRECIPITATION CHANCES TODAY...BUT STILL CARRY SOME ISOLATED
COVERAGE ACROSS THE SOUTHEAST ASSOCIATED WITH THE BAND OF ENHANCED
CU AS IT DROPS SOUTHEAST. OTHERWISE...WILL GO WITH HIGHER POPS NORTH
OF I-64 AFTER 22Z. SOME QUESTION AS TO HOW MUCH ACTIVITY LINGERS INTO
TONIGHT AS THE FRONT WASHES OUT OVER THE AREA. WILL DROP POPS BACK
FOR THE OVERNIGHT HOURS AS COVERAGE WILL LIKELY REMAIN MORE ISOLATED
TO SCATTERED ALONG THE BOUNDARY SINCE IT WILL BE HARD TO SEE MUCH
ORGANIZED ACTIVITY ALONG THE STALLED BOUNDARY. UPDATE WILL BE OUR
SHORTLY.
UPDATE ISSUED AT 705 AM EDT SAT JUL 20 2013
INGESTED THE MOST CURRENT OBSERVATION DATA TO ESTABLISH NEW TRENDS IN
THE FORECAST GRIDS. THE FORECAST WAS ON TRACK OVERALL...ALTHOUGH THE
FOG THAT WAS FORECAST TO FORM OVERNIGHT WAS NOT NEARLY AS EXTENSIVE
AS ORIGINAL THINKING INDICATED. WITH THE FORECAST IN PRETTY GOOD
SHAPE OVERALL...NO UPDATE IS PLANNED AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL LARGE SCALE
WEATHER PATTERN AND SENSIBLE WEATHER FOR THE NEXT COUPLE OF DAYS. A
WARM AND HUMID AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KENTUCKY
TODAY AND TOMORROW...AS SOUTHERLY FLOW PERSISTS AHEAD OF A SLOWLY
APPROACHING COLD FRONT. THE WEATHER TODAY SHOULD START OUT QUIET...AS
THE LACK OF A GOOD TRIGGER FOR CONVECTION SHOULD KEEP SHOWER AND
STORM ACTIVITY TO A MINIMUM THROUGH EARLY THIS AFTERNOON. SHOWERS AND
STORMS WILL GRADUALLY INCREASE IN COVERAGE BEGINNING MID AFTERNOON
TODAY...AS THE COLD FRONT FINALLY BEGINS MAKING ITS SOUTHWARD PUSH.
THE BEST CHANCE FOR RAIN WILL BEGIN EARLY THIS EVENING NORTH OF THE
MOUNTAIN PARKWAY. THE FRONT IS THEN PROGGED TO SAG SOUTHWARD OUT OF
THE OHIO VALLEY AND ACROSS CENTRAL AND EASTERN KENTUCKY OVERNIGHT
TONIGHT. ONCE LOSS OF DAYTIME HEATING BEGINS TO OCCUR...ANY SHOWERS
AND STORMS WILL DECREASE IN COVERAGE...WITH ONLY SCATTERED SHOWERS
AND ISOLATED STORMS EXPECTED DURING THE NIGHT TIME HOURS. ONCE THE
SUN HAS A BEEN UP FOR AWHILE ON SUNDAY...THE FRONT WILL BECOME ACTIVE
ONCE AGAIN...WITH NUMEROUS SHOWERS AND STORMS EXPECTED ACROSS THE
AREA FROM LATE SUNDAY MORNING THROUGH THE END OF THE DAY ON SUNDAY.
DUE TO SLUGGISH MIDDLE AND UPPER LEVEL WINDS...ANY SHOWERS AND STORMS
THAT FORM WILL BE VERY SLOW MOVING...WHICH COULD LEAD TO LOCALIZED
HEAVY RAIN AND POSSIBLY MINOR FLOODING ISSUES.
TEMPERATURES WILL BE QUITE HOT ONCE AGAIN TODAY...BUT WITH THE GROUND
STILL BEING SOMEWHAT MOIST FROM RECENT RAINFALL...AND WITH AREA
VEGETATION IN FULL LEAF...90 DEGREE READINGS WILL BE DIFFICULT TO
COME BY. WITH THAT IN MIND...LOWERED TODAYS HIGH TEMPERATURES ACROSS
THE BOARD TO REFLECT THIS. WILL LIKELY SEE READINGS TOP OUT MOSTLY IN
THE UPPER 80S AREA WIDE...WITH ISOLATED OCCURRENCES OF 90 HERE AND
THERE. HIGHS ON SUNDAY WILL LIKELY RUN SLIGHTLY BELOW NORMAL...DUE TO
SHOWER AND STORM ACTIVITY AND THE PASSAGE OF THE COLD FRONT. HIGHS ON
SUNDAY ARE EXPECTED TO TOP OUT IN THE LOWER 80S. OVERNIGHT LOWS WILL
BOTTOM OUT AROUND A BALMY 70 DEGREES. WINDS WILL REMAIN FAIRLY LIGHT
ACROSS THE AREA TODAY AND TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
THE SYNOPTIC PATTERN OVER THE EASTERN U.S. NEXT WEEK WILL FEATURE
THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EARLY IN THE WEEK WITH A
LEAD SHORTWAVE TRAVERSING THE OHIO VALLEY MONDAY AND MONDAY NIGHT.
OUR FORECAST WILL FEATURE THE HIGHEST RAIN CHANCES WITH THIS LEAD
SHORTWAVE ACTING AS THE FOCUS FOR SHOWERS AND THUNDERSTORMS MONDAY
AND MONDAY NIGHT. THIS FEATURE WILL PASS BY BUT THE UPPER LEVEL
TROUGH IS PROGGED TO HANG OUT WITH IT/S AXIS ALIGNED DOWN THE
APPALACHIAN CHAIN THROUGH AT LEAST FRIDAY...WITH SIGNS IN THE
MODELING THAT IT WILL GET REINFORCED NEXT WEEKEND. THIS SPELLS A
CONTINUATION OF UNSETTLED WEATHER WITH DAILY SHOWER AND THUNDERSTORM
CHANCES. A COLD FRONT WILL SLOWLY DROP THROUGH THE OHIO VALLEY
MIDWEEK RESULTING IN SCATTERED SHOWERS/STORMS...ESPECIALLY DURING
THE AFTERNOON AND EARLY EVENING HOURS. THE FRONT IS PROGGED TO DROP
TO OUR SOUTH FINALLY BY LATE THURSDAY INTO FRIDAY WITH A WEAK AREA
OF HIGH PRESSURE SLIDING DOWN INTO THE REGION. TRENDED RAIN CHANCES
DOWNWARD FROM INHERITED NUMBERS THURSDAY AND FRIDAY...BUT DID NOT
REMOVE THEM TOTALLY JUST YET.
THE GOOD NEWS IS THAT TEMPERATURES AND DEWPOINTS WILL BE ON A
DOWNWARD TREND DURING THE PERIOD. TEMPS WILL SETTLE BACK TO MORE
NORMAL VALUES FOR THIS TIME OF YEAR...WITH HIGHS GENERALLY IN THE
LOW TO MID 80S EACH DAY. DEWPOINTS WILL REMAIN HIGH...AROUND
70...UNTIL THE COLD FRONT DROPS TO OUR SOUTH LATE IN THE WEEK. THIS
SHOULD DROP DEWS BACK INTO THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 705 AM EDT SAT JUL 20 2013
FOG WAS NOT NEARLY AS WIDESPREAD AS THE EARLIER TAF INDICATED IT
WOULD BE...ESPECIALLY AT JKL AND SME. LOZ EXPERIENCE A FEW HOURS OF
FOG DURING THE PREDAWN HOURS THIS MORNING...WITH LIFR CONDITIONS FOR
A BRIEF PERIOD. AS FOR THE REST OF TODAY...SCATTERED SHOWERS AND
STORMS ARE EXPECTED TO BEGIN AFFECTING JKL AROUND 2Z TONIGHT...AND
LOZ AND SME AROUND 4Z...AS A COLD FRONT BEGINS TO MOVE SLOWLY
SOUTHWARD OUT OF THE OHIO VALLEY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...AR
LONG TERM...ABE
AVIATION...AR
AREA FORECAST DISCUSSION
NWS CARIBOU ME
310 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT. A DRIER AND
COOLER CANADIAN AIRMASS WILL THEN BUILD INTO THE AREA ON SUNDAY
AND HOLD OVER THE REGION THROUGH MONDAY. THE NEXT LOW PRESSURE
FROM THE GREAT LAKES WILL APPROACH THE REGION LATE MONDAY NIGHT
INTO TUESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
A COLD FRONT WILL MOVE THROUGH THE REGION OVERNIGHT FOLLOWED BY
CANADIAN HIGH PRES FOR SUNDAY. THIS HIGH WILL REMAIN IN CONTROL
THROUGH EARLY NEXT WEEK.
SOME CONVECTION HAS FIRED UP MAINLY ACROSS NORTHERN AND WESTERN
AREAS(SUB-SEVERE) AS SOME UPPER LEVEL DIVERGENCE SEEN ON THE SATL
WV IMAGERY AND 12Z UA. THE BEST SHOT FOR ANY STRONGER STORMS WILL
BE ACROSS THE DOWNEAST AND COAST INTO THE EVENING AND THEN
ACTIVITY WILL WEAKEN. THE BEST FORCING AND INSTABILITY WILL SHIFT
TO THE EAST. ADDED SOME FOG TO THE GRIDS FOR TONIGHT INTO EARLY
SUNDAY MORNING BASED ON ANTICIPATED CLEARING AND COOLER TEMPERATURES
W/A WET GROUND. ADJUSTED THE OVERNIGHT LOW USING A BLEND OF THE NAM12
AND ECMWF. POPS ARE A BLEND OF THE RUC AND DOWNSCALED NAM WHICH
SHOW PRECIP CHANCES WINDING DOWN AFTER 00Z.
SUNDAY LOOKS TO BE SUNNY AND PLEASANT W/HIGH PRES BUILDING IN FROM
CANADA. THINKING ATTM IS TO TAKE W/CONSISTENCY AND KEEP THE
MIDNIGHT CREW`S MAXES OF LOWER 70S NORTHERN CWA AND MID TO UPPER
70S CENTRAL AND DOWNEAST.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL SETTLE OVER THE AREA SUNDAY NIGHT. WITH LIGHT
WINDS...CLEAR SKIES AND RELATIVELY DRY AIR THE NIGHT WILL BE COOL
WITH LOWS DROPPING INTO THE 40S NORTH TO NEAR 50 DOWNEAST. THIS
WILL BE FOLLOWED BY A MOSTLY SUNNY AND SEASONABLE DAY ON MONDAY.
CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST LATE IN THE DAY
AS MOISTURE LIFTS NORTH FROM LOW PRESSURE TRACKING INTO SOUTHERN
NEW ENGLAND. CLOUDS WILL CONTINUE TO INCREASE MONDAY NIGHT AND
SOME RAIN MAY SPREAD INTO THE AREA LATE. THE BEST CHANCE FOR RAIN
WILL BE ALONG THE FRONTAL BOUNDARY WHICH WILL BE NEAR THE COAST.
THE LOW WILL TRACK JUST OFFSHORE ON TUESDAY BRINGING A CHANCE OF
RAIN TO THE AREA. THE BEST CHANCE FOR RAIN WILL BE ALONG COASTAL
AREAS. A COLD FRONT WILL APPROACH THE WEST LATE IN THE DAY. WARM
AND HUMID AIR MOVING NORTH AHEAD OF THE FRONT BENEATH RELATIVELY
COOLER AIR ALOFT MAY PRODUCE SOME THUNDERSTORMS IN WESTERN AREAS
LATE IN THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A WEAK LOW WILL BE TRACKING OFF THE COAST TUESDAY NIGHT AS A COLD
FRONT APPROACHES FROM THE WEST. THE LOW MAY BRING SOME RAIN TO
COASTAL AREAS EARLY TUESDAY NIGHT WHILE THE APPROACHING FRONT
BRINGS SOME SHOWERS AND POSSIBLY THUNDERSTORMS TO FAR WESTERN
AREAS. THE FRONT IS EXPECTED TO CROSS THE AREA EARLY WEDNESDAY
BRINGING SOME SHOWERS AND ISOLATED THUNDERSTORMS MAINLY TO THE
DOWNEAST REGION. HIGH PRESSURE SHOULD THEN BRING DRIER AIR WITH
CLEARING LATER WEDNESDAY INTO THURSDAY. ANOTHER FRONT MAY APPROACH
LATER FRIDAY INTO SATURDAY WITH INCREASED HUMIDITY FRIDAY INTO
SATURDAY.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: UNSETTLED CONDITIONS THROUGH AT THE START OF THE
PERIOD. MVFR NORTH...BECMG VFR EARLY EVENING. A BRIEF PERIOD OF
MVFR AND PERHAPS IFR FOR KBHB/KBGR THROUGH TONIGHT IN SHRA/TSRA
AND SOME FOG. VFR ALL SITES ON SUNDAY.
SHORT TERM: VFR CONDITIONS ARE EXPECTED SUNDAY NIGHT INTO MONDAY
WITH HIGH PRESSURE AND MOSTLY CLEAR SKIES. CONDITIONS WILL LIKELY
BEGIN VFR MONDAY NIGHT BUT MAY LOWER TO MVFR OR IFR LATE AS LOW
CLOUDS AND SHOWERS MOVE IN. MVFR CONDITIONS ARE EXPECTED TUESDAY
NIGHT INTO EARLY WEDNESDAY. HIGH PRESSURE MAY THEN BRING AN
IMPROVEMENT TO VFR WEDNESDAY INTO EARLY FRIDAY. LOWERING CLOUDS
AND SHOWERS MAY LOWER CONDITIONS TO MVFR FRIDAY NIGHT INTO
SATURDAY AS THE NEXT FRONT MOVES IN.
&&
.MARINE...
NEAR TERM: SEAS 3-5 FT ATTM. WAVE GUIDANCE INCLUDING THE SWAN
RUNNING TOO HIGH AS THE LATEST OBS SHOWED NO MORE THAN 4 FT(44027).
WINDS ARE EXPECTED TO BECOME GUSTY W/THE COLD FRONT TONIGHT W/SPEEDS
OF 25 KT BRIEFLY. THE WINDS WILL SUBSIDE ON SUNDAY DOWN TO 10 KT AS
HIGH PRES PUSHES E.
SHORT TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA THIS
WEEKEND INTO EARLY NEXT WEEK. HIGH PRESSURE SHOULD BRING CLEAR AND
PLEASANT CONDITIONS SUNDAY INTO MONDAY. LOWER CLOUDS...FOG AND
SOME RAIN MAY MOVE OVER THE WATERS ON TUESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...NORTON/HEWITT
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...NORTON/HEWITT/BLOOMER
MARINE...NORTON/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
630 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION LATE TODAY AND THIS EVENING.
A DRIER AND COOLER CANADIAN AIRMASS WILL THEN BUILD INTO THE AREA
ON SUNDAY AND HOLD OVER THE REGION THROUGH MONDAY. THE NEXT LOW
PRESSURE FROM THE GREAT LAKES WILL APPROACH THE REGION LATE MONDAY
NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...SATELLITE IMAGERY IS SHOWING MID CLOUDS ACROSS
MAINLY WESTERN PORTIONS OF THE FORECAST AREA THIS MORNING, WITH
SUNSHINE IN EASTERN MAINE. THESE CLOUDS WILL CONTINUE TO PUSH
EASTWARD THROUGH THIS MORNING. THERE`S NOT MUCH ON RADAR ATTM,
JUST SOME ISOLATED SHOWERS OVER THE SAINT JOHN VALLEY AND SOUTHERN
QUEBEC. ADDITIONAL SHOWERS WILL CONTINUE TO DEVELOP, THOUGH THE
BULK OF THE ACTIVITY SHOULD HOLD OFF UNTIL AT LEAST MID MORNING,
ESPECIALLY OVER NORTHERN MAINE. BOTH THE LATEST RUN AND HRRR MODEL
RUNS CONCUR WITH THIS THINKING. HAVE THEREFORE UPDATED THE
FORECAST TO REDUCE SKY COVER AND POPS OVER THE NEXT FEW HOURS.
OTHERWISE, THE PREVIOUS FORECAST LOOKS ON TRACK.
STRONG TO SEVERE STORMS ONCE AGAIN POSSIBLE TODAY, ESPECIALLY
ACROSS CENTRAL AND INTERIOR DOWNEAST MAINE. SPC HAS THESE AREAS IN
A SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON AND EVENING.
A STRONG COLD FRONT CURRENTLY LIES ACROSS CENTRAL QUEBEC EARLY THIS
MORNING, STRETCHING SOUTHWESTWARD THROUGH THE GREAT LAKES. THIS
FEATURE WILL SLOWLY MOVE SOUTHWARD TODAY, CROSSING THE FORECAST AREA
THIS AFTERNOON AND EVENING. MOISTURE CONVERGENCE ALONG THIS FRONT
WILL SERVE AS A FOCUS FOR SHOWERS AND THUNDERSTORMS, ESPECIALLY THIS
AFTERNOON. THE BEST MOISTURE AND INSTABILITY WILL LIE SOUTH OF A
HOULTON-MILLINOCKET-GREENVILLE LINE; DEWPOINTS AROUND 70 AND SBCAPES
OF 1000+ J/KG WILL EXIST IN THIS REGION THIS AFTERNOON. THIS
INSTABILITY COMBINED WITH 0-6KM SHEAR AROUND 40 KT WILL ALLOW
THUNDERSTORMS TO BECOME STRONG TO SEVERE OVER CENTRAL AND INTERIOR
DOWNEAST AREAS, WITH DAMAGING WINDS THE MAIN THREAT. PWATS NEARING 2
INCHES AND FREEZING LEVELS AOA 14 KFT INDICATE THAT HEAVY RAIN WILL
BE POSSIBLE AS WELL.
ACROSS THE CROWN OF MAINE, SHOWERS AND THUNDERSTORMS WILL BE MORE
SCATTERED IN NATURE, WITH SOME LOCATIONS EVEN SEEING SOME SUNSHINE
FROM TIME TO TIME. THE EARLIER TIMING OF THE FRONTAL PASSAGE AND
SLIGHTLY LOWER MOISTURE CONTENT WILL LIMIT ANY SEVERE POTENTIAL.
THAT BEING SAID, GUSTY WINDS AND BRIEFLY HEAVY DOWNPOURS ARE STILL A
POSSIBILITY WITH ANY STRONGER STORMS.
RELIEF FROM THE PAST FEW DAYS` MUGGINESS FINALLY ARRIVES TONIGHT AS
COOL, DRY CANADIAN HIGH PRESSURE SETTLES OVER THE REGION BEHIND THE
FRONT. SHOWERS AND THUNDERSTORMS WILL QUICKLY COME TO AN END AS
DEWPOINTS DROP AND SKIES CLEAR OUT. LOWS WILL BE MUCH MORE
COMFORTABLE, ESPECIALLY IN NORTHERN MAINE WHERE TEMPERATURES WILL
DROP TO AROUND 50. CENTRAL AND DOWNEAST MAINE WILL STAY BIT WARMER,
GENERALLY IN THE UPPER 50S TO AROUND 60.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
SUN STILL LOOKS TO BE SIG COOLER AND MUCH DRIER AS CANADIAN AIR
ACCOMPANIED BY SFC DWPTS IN THE 40S MOVES INTO THE FA. THE SFC HI
THEN CRESTS OVR THE FA SUN NGT PROVIDING GOOD RADIATIONAL COOLING
WITH OVRNGT LOWS DROPPING TO ARND 40 DEG F FOR THE COOLEST NRN
VLYS WITH 40S ELSEWHERE AND ARND 50 ALG THE IMMEDIATE DOWNEAST
COAST.
MON SHOULD CONT FAIR WITH MSLY SUNNY SKIES...WITH LGT SW RETURN
FLOW WINDS ARND SFC HI PRES DEPARTING E THRU THE MARITIMES ALLOWING
A RECOVERY OF HI TEMPS AT LEAST 5 DEG WARMER THAN SUN AFTN...XCPT
DOWNEAST AREAS WHICH WILL BE HELD BACK A FEW DEG DUE TO AN AFTN
SEA BREEZE.
MON NGT WILL BEGIN FAIR...THEN INCREASING HI CLDNSS WILL MOVE SW
TO NE ACROSS THE FA LATE MON NGT AHEAD OF SFC LOW PRES SYSTEMS AND
AN ASSOCIATED S/WVS ADVCG ENE FROM THE GREAT LKS AND CNTRL CAN.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
FCSTS OF THE NAO TELECONNECTION PATTERN TRENDING TOWARD NEAR ZERO
AND THE PNA PATTERN TRENDING POSITIVE SHOULD KEEP 500 MB HTS LOWER
THRU THE LONG RANGE AS THE MEAN LW TROF HOLDS OVR E CNTRL CAN AND
THE ERN GREAT LKS. SUBSEQUENTLY HI TEMPS THIS PD WILL MSLY BE AT
TO BLO NORMAL. THE COOLEST DAY POTENTIALLY...WILL BE TUE DUE TO
LOWERING CLD CVR AND SHWRS MOVG INTO THE FA FROM THE WSW AS A SFC
LOW FROM THE GREAT LAKES MOVES TOWARD NW ME TUE NGT. FOR NOW...
WE SPLIT THE DIFFERENCE BETWEEN BLENDED MODEL AND MOS HI TEMPS
WITH MODELS INDICATING MUCH COOLER HI TEMPS TUE AFTN DUE TO RN`
COOLED AIR...JUST IN CASE FASTER MODELS SUCH AS THE GFS ARE TO
FAST IN BRINGING THICKER CLD CVR AND SHWRS INTO THE FA TUE.
USING THE CONSENSUS APCH...WE SHOW THE GREATEST POPS WITH THE
GREAT LKS/E CNTRL CAN S/WV SYSTEMS TO BE TUE NGT WHERE WE SHOW
UP TO LOW LIKELY POPS OVR PTNS OF DOWNEAST AND E CNTRL PTNS
OF THE FA. WITH SRLY WINDS WHICH DIMINISH WITHE THE APCH OF THE
SFC TROF AXIS BY ERLY WED MORN...WE MENTION PATCHY LATE NGT FOG
WITH SHWRS FOR LATE TUE NGT. WITH LITTLE OR NO SBCAPE SHOWN FOR
OUR FA WITH THIS SYSTEM TUE AFTN AND TUE NGT...WE DO NOT INDICATE
ANY THUNDER WITH SHWRS ATTM...BUT THIS CAN BE RE-EVALUATED IN
FUTURE FCST UPDATES IN CASE ELEVATED CNVCTN PLAYS A ROLE.
OTHERWISE...A SLOW MOVG COLD FRONT WILL CROSS THE FA FROM QB
PROV LATER WED INTO WED EVE AS THE UPPER TROF CROSSES THE REGION
BRINGING THE CHC OF ADDITIONAL SHWRS. CANNOT RULE OUT THUNDER...
BUT GIVEN THE RANGE OF TMG OF THE COLD FRONT CROSSING FOR WED...
WE WILL WILL HOLD OFF IN CALLING FOR THUNDER IN THE FCST GRIDS
ATTM FOR THIS PD. OTHERWISE...PRTL CLRG IS XPCTD WED NGT THRU
FRI...ALTHOUGH THE CONSENSUS OF MODEL SOLUTIONS STALL THE COLD
FRONT JUST E OF THE FA DURG THIS TM...RESULTING IN US KEEPING CHC
SHWRS POPS AND CLDNSS BANKED UP ALG THE SE PERIPHERY OF THE FA
DURG THESE PDS. FOR NOW...WE SHOW NEAR NORMAL HI AND LOW TEMPS
ACROSS THE FA TUE NGT THRU FRI...SUBJECT TO CHG OF COURSE DEPENDING
ON FUTURE MODEL TRENDS ON THE WX SYSTEMS XPCTD TO AFFECT THE FA
DURING THE LONG RANGE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: OUTSIDE OF SOME LINGERING MVFR VISIBILITIES IN FOG AT
KBGR AND KBHB, VFR CONDITIONS WILL PREVAIL THIS MORNING BEFORE
GIVING WAY TO MVFR AS ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
AFFECTS THE REGION. THE SOUTHERN TERMINALS WILL SEE THE STRONGEST
ACTIVITY, WITH HEAVY RAINFALL AND GUSTY WINDS POSSIBLE. IFR
CONDITIONS ARE POSSIBLE IN ANY THUNDERSTORMS. A COLD FRONT WILL
QUICKLY CROSS THE REGION TONIGHT, FOLLOWED BY MUCH DRIER AIR. AS
SUCH, PRECIPITATION WILL END AND SKIES CLEAR. CONDITIONS WILL
RETURN TO VFR AT ALL TERMINALS BY 06Z.
SHORT TO LONG TERM: VFR ALL SITES THRU MON NGT...THEN LOWERING TO
MVFR IN LOW CLDNSS AND SHWRS FROM SW TO NE BY TUE AFTN AND TO IFR
WITH SHWRS AND PATCHY FOG TUE NGT. CONDITIONS THEN SLOWLY IMPROVE
TO MVFR BY WED AFTN WITH LESSENING CVRG OF SHWRS.
&&
.MARINE...
NEAR TERM: SOUTHWEST WINDS 15-20 KT AND SOUTH SWELL OF 4 TO 6
FEET WILL CONTINUE THROUGH TODAY AHEAD OF A COLD FRONT MOVING
SOUTH OUT OF QUEBEC. THIS FRONT WILL CROSS THE WATERS THIS
EVENING, TURNING WINDS TO THE NW AND ALLOWING SEAS TO SUBSIDE.
THEREFORE, THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS REMAINS IN
PLACE THROUGH THIS EVENING.
SHORT TO LONG TERM: NO HDLNS NEEDED UNTIL TUE NGT INTO WED...WHEN
AN SCA FOR HAZ SEAS MAY BE NEEDED FOR OUR OUTER MZS DUE TO A SRLY
WIND FETCH AHEAD OF LOW PRES MOVG NE THRU ERN QB. WENT BLO A BLEND
OF WW3 AND SWAN NAM BY USING THE SMOOTHING FUNCTION ADJACENT TO
LAND...WHICH LOWERED WV HTS MOST OVR THE INNER BAY/HARBOR MZ.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM EDT THIS
EVENING FOR ANZ050-051.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1011 PM EDT SUN JUL 21 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE
EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY
STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES.
MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST
ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST WX ANALYSIS SHOWS WEAKENING SFC FRONT FROM JUST SOUTH OF
LONG ISLAND NY...EXTENDING W-SW BACK INTO THE OHIO AND MIDDLE
MISSOURI VALLEYS. BULK OF CONVECTION WHICH ERUPTED ALONG SFC
TROUGH...AND DUMPED BETWEEN 3 AND 5 INCHES OVER PARTS OF THE
PIEDMONT AND MIDDLE PENINSULA EARLIER THIS EVENING...HAVE GREATLY
DIMINISHED IN INTENSITY AND AREAL CVG WITH LOSS OF HEATING AND
AS NOCTURNAL STABILITY SETS IN. HRRR HAS HANDLED TRENDS RATHER
WELL THIS EVENING AND HV CONTINUED TO LEAN IN ITS DIRECTION
OVERNIGHT. OVERALL, WHILE INSTABILITY AND SYNOPTIC SCALE FORCING
WANE SIGNIFICANTLY OVERNIGHT, WEAK LLVL CONVERGENCE ALONG THE
TROUGH AXIS PERSISTS. THUS, WILL RETAIN A SLIGHT CHC/LOW CHC POP
FOR AN ISO TO WIDELY SCT SHRA AFTER MIDNIGHT. ANOTHER WARM AND
HUMID OVERNIGHT IS EXPECTED WITH LOWS IN THE LOW/MID 70S...UNDER A
PARTLY TO MOSTLY CLOUDY SKY.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE
BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS
TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT
OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY
AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE
FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN
SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF
SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH
DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM
THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS
RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN
FROM SLOW MOVING STORMS.
THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY
WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE
THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY
LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W.
HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO
WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER
80S TO LOW 90S.
THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE
REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST
BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME.
HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH
THE PERIOD SHOULD RANGE FROM 70-75.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT
EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR
JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA.
WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT.
THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH
AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL
NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW
CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S
THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN
MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE
PERIOD.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
SHOWERS AND TSTMS CONT TO AFFECT THE CWA AS OF 0030Z WITH MOST OF
THE ACTIVITY FROM THE EASTERN SHORE TO SE VA. OUTSIDE OF
PRECIPITATION...CONDS HAVE BEEN GENERALLY VFR...WITH MVFR/IFR IN
SHOWERS AND TSTMS. A STNRY FRONT CONTS ALONG THE PA/MD LINE AND A
SFC TROUGH IS PUSHING THRU CENTRAL VA. MOST OF THE PRECIP ACTIVITY
SHOULD BE ENDED BY MIDNIGHT. WINDS WILL BE LIGHT AND VRBL
OVERNIGHT AND MOST OF THE CLOUDS SHOULD CLEAR FOR A SHORT PERIOD
OF TIME. AS WITH THE PREVIOUS FEW NIGHTS...EXPECT SOME MVFR
STRATUS/STRATOCU CLOUDS TO DEVELOP DURING THE EARLY MORNING AS LOW
LEVEL MOISTURE GETS TRAPPED UNDER WEAK INVERSION. THESE CLOUDS
SHOULD DIMINISH BY MID TO LATE MORNING ALONG WITH ANY PTCHY FOG
THAT DEVELOPS.
OUTLOOK...SCATTERED MAINLY AFTN AND EARLY EVENING TSTMS CAN BE
EXPECTED MON THROUGH FRI WITH THE HIGHEST CHANCES MON AND WED.
AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN. PATCHY IFR FOG
NEAR SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR IS INDICATED
THROUGH MID WEEK.
&&
.MARINE...
SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA
WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS
ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME
HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND
EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES.
EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/LKB
NEAR TERM...MAM
SHORT TERM...AJZ/LKB
LONG TERM...TMG/JEF
AVIATION...LSA
MARINE...LSA
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
837 PM EDT SUN JUL 21 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE
EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY
STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES.
MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST
ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
CURRENT SATELLITE IMAGERY AND REGIONAL RADAR MOSAIC INDICATE AN
ORGANIZED LINE OF THUNDERSTORMS EXTENDING FROM NORTHERN VA SW ALONG
THE PIEDMONT AND MOVING EAST. THIS LINE OF STORMS IS BEGIN DRIVEN BY
THE TAIL END OF A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN MID
ATLANTIC...INTERACTING WITH A SURFACE TROUGH OVER THE AREA...AND
FEEDING OFF AN AXIS OF >2500 J/KG OF MLCAPE PER SPC HRRR BASED
MESOANALYSIS. ADDITIONAL SEA/BAY BREEZE CONVECTION IS DEVELOPING
ACROSS THE LOWER BAY AND MD ATLANTIC COAST.
THE PRIMARY LINE SHOULD PROGRESS EAST ACROSS CENTRAL/S-CENTRAL VA
THROUGH THE LATE AFTERNOON AND EARLY EVENING. INITIALLY...0-6KM BULK
SHEAR VALUES ARE PROGGED TO BE ~25KT BEFORE DECAYING BY EARLY
EVENING. THEREFORE...THE BEST CHANCE OF AN ISOLATED SEVERE STORM
(MAINLY WIND GUST) WOULD BE ACROSS THE NORTHERN PORTION OF THE AREA
THROUGH THE REMAINDER OF THE AFTERNOON. THE SOUTHERN END OF THE LINE
SHOULD EVENTUALLY DISSIPATE THIS EVENING DUE TO THE LOSS OF SURFACE
HEATING AND A LACK OF LARGE SCALE FORCING AS THE SHORTWAVE ENERGY
PULLS TOWARD NEW ENGLAND. FARTHER NE IN THE LOCAL AREA...SCT POPS
WILL BE MAINTAINED THROUGH THE EVENING/EARLY OVERNIGHT IN CLOSER
PROXIMITY TO THE SHORTWAVE. WARM AND HUMID CONDITIONS WILL PERSIST
OVERNIGHT WITH LOWS IN THE LOW/MID 70S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE
BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS
TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT
OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY
AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE
FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN
SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF
SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH
DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM
THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS
RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN
FROM SLOW MOVING STORMS.
THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY
WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE
THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY
LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W.
HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO
WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER
80S TO LOW 90S.
THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE
REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST
BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME.
HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH
THE PERIOD SHOULD RANGE FROM 70-75.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT
EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR
JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA.
WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT.
THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH
AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL
NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW
CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S
THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN
MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE
PERIOD.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
SHOWERS AND TSTMS CONT TO AFFECT THE CWA AS OF 0030Z WITH MOST OF
THE ACTIVITY FROM THE EASTERN SHORE TO SE VA. OUTSIDE OF
PRECIPITATION...CONDS HAVE BEEN GENERALLY VFR...WITH MVFR/IFR IN
SHOWERS AND TSTMS. A STNRY FRONT CONTS ALONG THE PA/MD LINE AND A
SFC TROUGH IS PUSHING THRU CENTRAL VA. MOST OF THE PRECIP ACTIVITY
SHOULD BE ENDED BY MIDNIGHT. WINDS WILL BE LIGHT AND VRBL
OVERNIGHT AND MOST OF THE CLOUDS SHOULD CLEAR FOR A SHORT PERIOD
OF TIME. AS WITH THE PREVIOUS FEW NIGHTS...EXPECT SOME MVFR
STRATUS/STRATOCU CLOUDS TO DEVELOP DURING THE EARLY MORNING AS LOW
LEVEL MOISTURE GETS TRAPPED UNDER WEAK INVERSION. THESE CLOUDS
SHOULD DIMINISH BY MID TO LATE MORNING ALONG WITH ANY PTCHY FOG
THAT DEVELOPS.
OUTLOOK...SCATTERED MAINLY AFTN AND EARLY EVENING TSTMS CAN BE
EXPECTED MON THROUGH FRI WITH THE HIGHEST CHANCES MON AND WED.
AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN. PATCHY IFR FOG
NEAR SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR IS INDICATED
THROUGH MID WEEK.
&&
.MARINE...
SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA
WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS
ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME
HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND
EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES.
EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/LKB
NEAR TERM...AJZ
SHORT TERM...AJZ/LKB
LONG TERM...TMG/JEF
AVIATION...LSA
MARINE...LSA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EDT SAT JUL 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EDT SAT JUL 20 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NE
CANADA AND A WEAK RIDGE INTO MANITOBA RESULTING IN CONFLUENT WNW
FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...A RIDGE EXTENDED FROM
SRN MANTIOBA INTO NW ONTARIO TO NW LAKE SUPERIOR. ABUNDANT DIRUNAL
CU HAD DEVELOPED IN THE COOL AIR TO THE NORTH OF LAKE SUPERIOR WHERE
850 MB TEMPS WERE DOWN TO 2C-3C. FARTHER SOUTH...VIS LOOP SHOWED
ONLY SCT CU OVER THE W HALF OF UPPER MI.
TONIGHT...WITH CLEAR SKIES AND LIGHT WINDS TONIGHT...FAVORABLE
RADIATIONAL COOLING CONDITIONS IN THE DRY AIRMASS OVER THE REGION
(PWAT BELOW 0.50 INCH)WILL ALLOW TEMPS TO DROP TO NEAR THE LOW END
OF GUIDANCE...NEAR 40 OVER THE COLDER INLAND LOCATIONS.
SUN...AS THE SFC HIGH SHIFTS EAST OF THE AREA AND THE MID LEVEL
FLOW BECOMES MORE ZONAL...SRLY FLOW AND WAA WILL INCREASE AHEAD OF
APPROACHING SHORTWAVE AND FRONTAL SYSTEM OVER THE NRN PLAINS. TEMPS
SHOULD CLIMB INTO THE LOWER TO MID 70S INLAND WITH LOWER READINGS IN
THE MID TO UPPER 60S ALONG THE GREAT LAKES. MODELS SUGGEST THAT THE
GREATEST INCREASE IN MOISTURE AND STRONGER 300-310K ISENTROPIC LIFT
WILL REMAIN TO THE SOUTH AND WEST OF UPPER MI FROM SRN MN INTO
CNTRL WI LATE SUN AFTERNOON. SO...THE FCST MAINTAINS ONLY SLIGHT
CHANCE POPS INTO THE FAR WEST
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 419 PM EDT SAT JUL 20 2013
UPPER AIR PATTERN THROUGH NEXT WEEK DRIVEN BY TWO AREAS OF LOWER
HEIGHTS...ONE OVER GULF OF ALASKA/BRITISH COLUMBIA AND THE OTHER
VCNTY OF HUDSON BAY ACROSS QUEBEC. IN BTWN THESE TWO...WNW FLOW
HOLDS IN PLACE FROM WESTERN CANADA ACROSS GREAT LAKES. MOST
PERSISTENT RIDGING WILL BE LIMITED TO SOUTHWEST PART OF CONUS.
PATTERN DOES NOT LOOK APPRECIABLY WARM...ESPECIALLY COMPARED TO
THE RECENT HEAT WAVE THAT AFFECTED GREAT LAKES REGION. OVERALL
TEMPS THROUGH THE PERIOD WILL BE AT OR SLIGHTLY BLO NORMAL /NORMAL
HIGH TEMPS ON AVERAGE THIS TIME OF YEAR ARE IN THE UPR 70S NORTH TO
LOWER 80S SOUTH/. WARMEST DAY MOST LIKELY ON MONDAY AS WARM FRONT
LIFTS ACROSS UPPER LAKES RESULTING IN SW SFC WINDS. COLD FRONT
MOVES IN MONDAY NIGHT THOUGH...MAKING THIS STAY IN THE WARM SECTOR
VERY BRIEF. SHRA/TSRA POSSIBLE AS THESE FRONTAL BOUNDARIES AFFECT
THE AREA. ONLY OTHER CHANCE OF RAIN ARRIVES LATER THURSDAY INTO
FRIDAY AS ANOTHER SFC TROUGH CROSSES THE REGION. WEAK HIGH PRESSURE
AND DRY WEATHER WILL DOMINATE THE WEATHER PATTERN REST OF THE LONG
TERM.
FIRST FOCUS IN LONGER TERM IS SHORTWAVE PRESSING INTO SCNTRL CANADA
ON SUNDAY NIGHT AND SFC LOW/TROUGH MOVING ACROSS NORTHERN PLAINS.
SLIGHT H85 TEMP/MOISTURE ADVECTION OVER UPR MICHIGAN AHEAD OF THE
WAVE AND SFC TROUGH...BUT INSTABILITY IS PRETTY MINIMAL WITH MUCAPES
1-6KM A FEW HUNDRED J/KG AT BEST...MAINLY OVER FAR WEST LK SUPERIOR
CLOSER TO STRONGEST H85-H7 MOISTURE TRANSPORT. FCST SOUNDINGS SHOW
INCREASE OF H8-H7 MOISTURE BUT HINT AT DRY AIR BLO AND ABOVE THIS
LAYER. WITH LACK OF INSTABILITY AND DEEP MOISTURE AND LARGER SCALE
FORCING...THINK COVERAGE TO ANY SHRA/TSRA WILL BE LIMITED SUN NIGHT
BUT CANNOT COMPLETELY RULE IT OUT.
SEEMS THAT BETTER CHANCES FOR SHRA/TSRA OCCUR ON MONDAY IN THE
MORNING DUE TO CLOSER PROXIMITY OF SHORTWAVE/H85 TROUGH AND
RESULTING SHARPER WARM AIR ADVECTION AND INCREASING H85 MOISTURE
TRANSPORT. EXPECT THIS WARM AIR ADVECTION SHRA/ISOLD TSRA TO SHIFT
NORTH BY AFTN ALONG SFC WARM FRONT AND THEN...PROVIDED THERE IS
ENOUGH CLEARING OF MORNING CLOUDS/SHRA/TSRA...THERE SHOULD BE PERIOD
OF BUILDING INSTABILITY DURING PEAK HEATING AS TEMPS WARM INTO THE
UPR 70S/LWR 80S. MLCAPES TOP OUT AROUND 800-1200J/KG...HIGHEST
ALONG WI BORDER. DEEP LAYER SHEAR INCREASES IN WARM SECTOR OUT
AHEAD OF COLD FRONT TO 30-40 KTS AS SHORTWAVE CROSSES NORTHERN
ONTARIO AND ADJACENT LK SUPERIOR. SOUNDINGS SHOW A BIT OF CAPPING
AROUND H8 AND THIS ADDS UNCERTAINTY TO INITIATION. BASED ON CAPE AND
SHEAR BALANCE...THERE SEEMS TO BE AT LEAST SMALL POTENTIAL FOR ISOLD
SVR STORMS. SUPERCELLS POSSIBLE AS WINDS SHOW SUFFICIENT VEERING WITH
HEIGHT. HAIL/WIND PRIMARY HAZARDS WITH LOWER WBZERO HEIGHTS AROUND
11KFT AND DCAPE UP TO 1000J/KG. ALL THIS IS CONDITIONAL ON HOW MUCH
INSTABILITY CAN MATERIALIZE. SINCE SPC DAY 3 DID INDICATE SEE TEXT
OVER THE AREA...THINK IT IS WORTH AN HWO MENTION.
COLD FRONT BLOWS THROUGH CWA PRETTY QUICKLY MONDAY EVENING/EARLY
OVERNIGHT. TRENDED TOWARD LOWER POPS 6Z-12Z ON TUESDAY WITH DRYING
NOTED IN SOUNDINGS AND GFS/ECMWF SHOWING LITTLE IF ANY QPF IN THAT
TIME FRAME THE LAST FEW MODEL RUNS. IN WAKE OF THE COLD FRONT ON
TUESDAY...COULD END UP WITH NEARLY CARBON COPY OF TODAY...COOL TEMPS
ALONG LK SUPERIOR/HIGHER SWIM RISK AND READINGS INTO LOWER 70S TOWARD
WI BORDER. CUT GUIDANCE TEMPS FOR TUESDAY NIGHT WITH HIGH CENTER
OVERHEAD. FAVORED COLD SPOTS OVER MAINLY WEST COULD REACH TO AROUND
40 DEGREES. STAYS QUIET THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE
SLOWLY RETREATS.
NEXT CHANCE OF RAIN RETURNS THURSDAY INTO FRIDAY. MODELS HAVING
TOUGH TIME HANDLING SHORTWAVE TROUGH PUSHING THROUGH IN WNW FLOW
ALOFT. LATEST GFS AND ECMWF WOULD INDICATE SHORTWAVE PASSAGE
THURSDAY OR THURSDAY NIGHT. BLEND OF CONSENSUS SHOWS SLIGHT
CHANCE/LOW CHANCE POPS AS ANOTHER COLD FRONT CROSSES THE AREA
TIED TO THE WAVE. SATURDAY LOOKING PRETTY COOL YET AGAIN BEHIND
THIS COLD FRONT. PROBABLY WILL END UP SIMILAR TO WHAT IS OCCURRING
TODAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 139 PM EDT SAT JUL 20 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD AS HIGH
PRESSURE GRADUALLY BUILDS INTO THE REGION. NRLY WINDS WILL DIMINISH
THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EDT SAT JUL 20 2013
AS HIGH PRESSURE BUILDS INTO THE NORTHERN GREAT LAKES...WINDS WILL
DIMINISH THIS EVENING TO LESS THAN 20 KNOTS. SRLY WINDS WILL
INCREASE TO AROUND 20 KNOTS AHEAD OF A LOW PRESSURE TROUGH MOVING
THROUGH THE AREA ON MONDAY. NORTH TO NORTHWEST WINDS WILL THEN INCREASE
TO 20 TO 30 KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND A COLD
FRONT MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN
BELOW 20 KNOTS THROUGH THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT SAT JUL 20 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT SAT JUL 20 2013
FAIR WEATHER WILL RETURN THIS WEEKEND WITH SEASONABLE TEMPERATURES
AND IT WILL BE MUCH LESS HUMID. HIGHS WILL BE CLOSER TO NORMALS FOR
THIS TIME OF YEAR WITH LOWER TO MIDDLE 80S TODAY AND AROUND 80 ON
SUNDAY. THE NEXT CHANCE OF SHOWERS AND STORMS WILL COME LATE SUNDAY
NIGHT AND MONDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 330 AM EDT SAT JUL 20 2013
HIGH PRESSURE WILL BRING FAIR WEATHER THIS WEEKEND WITH SEASONABLE
TEMPERATURES. HIGH TEMPERATURES TODAY WILL REACH THE LOWER TO MIDDLE
80S AND UPPER 70S TO LOWER 80S ON SUNDAY.
A LOW PRESSURE SYSTEM WILL BRING THE NEXT CHC FOR SHOWERS AND
TSTORMS AS EARLY AS LATE SUNDAY NIGHT WITH A LITTLE BETTER CHC FOR
PCPN ON MONDAY AS AN UPPER LEVEL TROF AXIS MOVES ACROSS THE LOWER
GREAT LAKES REGION.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT JUL 20 2013
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 726 PM EDT FRI JUL 19 2013
THE BIG QUESTION IS DOES A LINE OF STORMS FORM JUST AHEAD OF THE
FRONT OR NOT? CURRENTLY SCATTERED STORMS ARE TRYING TO ORGANIZE
NEAR MBL...WHICH IS JUST AHEAD OF THE COLD FRONT. THE TIMING TOOL
TAKES THAT TO MKG BY 0430Z AND TO THE I-94 TAF SITES BY 11Z. THIS
SEEMS TO SLOW... THE LATEST HRRR REDEVELOPS STORMS OVER SOUTHERN
LAKE MICHIGAN BY 01Z AND HEADS THOSE STORMS OUT OF THE CWA BY 04Z.
SINCE THERE IS A JET SPEED MAX THAT COMES THROUGH THE AREA IN THE
03Z TIME FRAME... IT WOULD SEEM THERE IS A GOOD CHANCE THE STORMS
COULD YET BETTER ORGANIZE. SO NOT HAVING ANYTHING SOLID TO TRACK
INTO THE TAF SITES...I KEPT THE VCTS GOING 09Z AT MOST OF THE TAF
SITES. BEHIND THE FRONT SKIES WILL CLEAR SO MOST OF SATURDAY
SHOULD BE CLEAR WITH A NORTHWEST WIND AROUND 10 KNOTS.
&&
.MARINE...
ISSUED AT 330 AM EDT SAT JUL 20 2013
WAVE HEIGHTS WILL RAMP BACK UP LATER TODAY AS NNW TO NORTH WINDS
INCREASE LATE THIS MORNING/AFTN. WE WILL HOIST A SMALL CRAFT
ADVISORY TO COVER THIS FROM LATE THIS MORNING THROUGH THE LATE
EVENING HOURS TONIGHT. A BEACH HAZARD STATEMENT HAS ALSO BEEN
ISSUED DETAILING THE HIGH SWIM HAZARD RISK THAT IS IN PLAY AGAIN
TODAY.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT SAT JUL 20 2013
NO HYDRO ISSUES WITH HIGH PRESSURE BUILDING IN THIS WEEKEND BRINGING
FAIR AND DRY WX.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT 11 AM TODAY THROUGH LATE THIS
EVENING FOR MIZ037-043-050-056-064-071.
LM...SMALL CRAFT ADVISORY 11 AM TODAY THROUGH LATE THIS EVENING
FOR LMZ844>849.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
932 AM CDT Sat Jul 20 2013
.UPDATE...
Issued at 931 AM CDT SAT JUL 20 2013
Scattered convection has developed this morning along a lingering
frontal boundary surface boundary near US 50, with additional storms
further north near an elevated boundary near 850 hPa. Winds aloft are
quite weak, so this activity will be pulse in nature and slow to
drift eastward. Latest RAP and NAM suggest that this boundary, both
at the surface and aloft, may maintain its definition and nudge
northward slightly through the afternoon. This may keep rain chances
going into the afternoon for areas near and south of the Missouri
River. Trying to pinpoint location and timing of this activity is
quite difficult, so the forecast was adjusted to account for the
current location of showers and storms, blending into broader low-
chance PoPs through the afternoon.
&&
.SHORT TERM...(Today through Sunday)
Issued at 316 AM CDT SAT JUL 20 2013
The main forecast challenge for today will be precipitation chances
along a weak frontal boundary and pre-frontal trough stretching over
the forecast area. Convection-allowing models are hinting at the
possibility for re-development along the pre-frontal trough between
daybreak and mid-morning; however, this could occur on the southern
edge or even further south of the CWA, and should be fairly isolated
in nature. With the main boundary stalling south of I-70 today, the
main question will be whether afternoon storm development will occur
along the front. With only weak low-level convergence and a stout
capping inversion, afternoon convection still looks fairly unlikely.
The further south the surface boundary can sag this afternoon, the
better the chances will be for precipitation, since this would keep
the front a bit further from the midlevel thermal axis and should
result in a weaker cap... so have kept the higher PoPs confined to
areas south of I-70 for the late afternoon and early evening hours.
After this boundary becomes a bit more diffuse and continues to
filter southward out of the CWA, the main chances for precipitation
will come with a shortwave trough dropping southeast out of central
SD. Convection will develop during the afternoon or evening hours in
central SD and into eastern Nebraska, and will push southeast while
continuing to develop across the forecast area late tonight and into
Sunday. The severe weather potential still looks low with weak low-
level shear, moderate instability but lackluster lift, and
unimpressive downdraft CAPE. Although PWATs are fairly high and the
chance for measurable precipitation looks the highest in quite a
while for Sunday, have kept precipitation totals less than an inch
through the period due to a decent southeastward progression of the
wave and disintegration of the surface boundary.
Temperatures today will be held down slightly by scattered cloud
cover and weak mixing, but should still reach the lower 90s on both
sides of the frontal boundary. Widespread cloud cover and scattered
precipitation will keep temperatures cooler on Sunday, and should
hold highs mainly in the 80s across the region.
.LONG TERM...(Monday through Friday)
Issued at 316 AM CDT SAT JUL 20 2013
Previous forecast philosophy remains on track with regards to
extended forecast as operational models continue to show good
agreement with the general upper pattern. Persistent northwest flow
aloft is expected through much of the work week, with a general
flattening of the upper trough by the end of the week. This pattern
will result in continued chances for precipitation and temperatures
near or slightly below seasonal levels. Several upper disturbances
are projected to move through the region, and with a surface frontal
boundary residing in close proximity to the forecast area,
sufficient conditions will help promote the development of scattered
thunderstorms. The exact evolution, coverage, timing, and rainfall
amounts from convective episodes are still somewhat ill-resolved
with this period still several days away and the dependency of
subsequent days of convection and its effect on surface feature
positions. Beyond the inherent uncertainty with this type of setup,
confidence continues to increase that much of the forecast area will
see the potential for multiple rounds of precipitation through the
upcoming workweek. Maximum temperatures will progressively cool,
with highs in the 80s in most locations by midweek.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 637 AM CDT SAT JUL 20 2013
A few showers and thunderstorms will impact portions of west central
Missouri and eastern Kansas this morning, but should diminish over
the next several hours and remain south of all TAF sites. Otherwise,
mainly VFR conditions are expected today with a possibility for
additional storm development in central KS/MO this afternoon, and a
high probability of widespread storms around 12z Sunday morning. A
frontal boundary will also stall around or south of I-70 today, which
will keep winds generally light but variable in direction.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Laflin
LONG TERM...Blair
AVIATION...Laflin
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
422 PM MDT SAT JUL 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
MADE A QUICK UPDATE TO CHANGE AFTERNOON WX TO COVERAGE AND
INCREASE POPS. A COUPLE OF STRONG STORMS HAVE POPPED UP WITH
REPORTS OF HEAVY RAIN...SMALL HAIL...AND GUSTY WIND. SCT
PREVIOUS DISCUSSION...
CONVECTIVE ACTIVITY THIS AFTERNOON WILL CONTINUE TO DEVELOP OVER
THE NEXT COUPLE OF HOURS BUT SHOULD DIMINISH PRETTY QUICK WITHOUT
THE SHEAR IN PLACE. HRRR MODEL SHOWING JUST SCATTERED ACTIVITY AT
BEST OVER THE NORTHEASTERN HALF OF THE CWA THIS EVENING.
WITH AN UPPER TROUGH OVER THE EASTERN STATES AND A RIDGE TO OUR
WEST...THE AREA IS UNDER A WEST-NORTHWEST FLOW. A DISTURBANCE...BOTH
AT THE SURFACE AND ALOFT MOVES INTO SOUTHERN SASK LATER
TONIGHT...KEEPING SHOWERS/THUNDERSTORMS GOING OVERNIGHT MAINLY TO
THE NORTHEAST ZONES.
SUNDAY...DISTURBANCE MOVES SOUTHEAST AND THROUGH THE CWA BRINGING AN
INCREASE IN WEST WINDS DURING THE AFTERNOON. THEY SHOULD BE STRONG
ENOUGH TO CAUSE PROBLEMS FOR FORT PECK LAKE FROM NOON UNTIL 9
PM...SO ISSUED A LAKE WIND ADVISORY.
ON MONDAY...BACKDOOR FRONT THAT LIES NW TO SE ACROSS MONTANA SUNDAY
NIGHT HELPS TO FIRE UP THUNDERSTORMS AS A VORT MAX MOVES IN FROM THE
WEST. ACTIVITY MOVES IN FROM THE WEST WITH MORE ACTIVITY EXPECTED
DURING THE EVENING. TFJ
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
AN UPPER LEVEL RIDGE IN THE WEST AND A PERSISTENT UPPER TROUGH
CENTERED OVER NORTHERN QUEBEC WILL MAINTAIN A NORTHWEST FLOW OVER
NORTHEAST MONTANA THROUGH MOST OF THE PERIOD. WEAK EMBEDDED
DISTURBANCES IN THE UPPER FLOW WILL BRING ISOLATED TO SCATTERED
THUNDERSTORMS TO THE REGION THROUGHOUT THE PERIOD.
MONDAY EVENING AND OVERNIGHT GFS SENDS A DISTURBANCE FLOWING
ALONG THE STATIONARY BOUNDARY THAT WILL INITIATE THUNDERSTORMS
ACROSS NEMONT. WITH SOME AGREEMENT FROM THE 00Z EC...WENT AHEAD
AND ADJUSTED POPS TO CHANCE.
TUESDAY THROUGH SATURDAY THE FLUCTUATING STATIONARY BOUNDARY AND
WEAK DISTURBANCES WILL GENERATE A FEW STORMS EACH DAY. THIS IS
REFLECTED IN THE INHERITED GRIDS AND NO CHANGES ARE PLANNED HERE.
SCT
SYNOPTIC SET UP... A LARGE HIGH PRESSURE HEAT DOME IS CENTERED
OVER THE LOWER INTER-MOUNTAIN WEST. A RIDGE SPUR RUNS NORTH OF THIS
DOME INTO BRITISH COLUMBIA. A LARGE TROUGH EXTENDS FROM THE
NORTHERN US PLAINS INTO MANITOBA AND UP THROUGH NUNAVUT. NORTHEAST
MONTANA LIES BETWEEN THESE TWO FEATURES IN A ZONAL TO NORTHWEST
FLOW PATTERN. ANOTHER LARGE TROUGH LIES OFF THE COAST OF BRITISH
COLUMBIA.
MONDAY NIGHT THROUGH THURSDAY NIGHT... NORTHWEST FLOW WILL END UP
ALLOWING HIGH POP CHANCE ACROSS THE NORTHEAST DRYING TOWARD THE
SOUTHWEST. THIS GRADIENT WILL BEGIN A BIT MORE SHARP MONDAY NIGHT
BUT WILL SLOWLY DIFFUSE OUT TOWARD THURSDAY NIGHT AS JETS AND
SHORTWAVES BECOME MORE FUZZY IN TIME. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS DO EXIST ALMOST EVERY PERIOD.
FRIDAY ONWARD... THE PATTERN WILL BECOME A LITTLE MORE PROGRESSIVE
AS THE RIDGE TO THE WEST SETTLES OVER THE MONTANA HIGH PLAINS.
THIS SHOULD EDGE TEMPERATURES UP BUT POPS WILL PROBABLY REMAIN AS
THE ATMOSPHERE BECOMES MORE DESTABILIZED. HOWEVER... QPF IS
EXPECTED TO LOWER AS PLANTS BEGIN TO STRESS FROM PROGRESSIVELY
DRIER HOTTER DAYS AND SOILS FOLLOWED BY THE SURFACE LAYER OF THE
ATMOSPHERE DRY OUT. GAH
&&
.AVIATION...
GENERALLY VFR. HOWEVER A WEAK UPPER LEVEL DISTURBANCE FLOWING
OVER A STATIONARY SURFACE BOUNDARY WILL INITIATE ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS THAT COULD AFFECT ANY OF
THE TAF SITES. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM NOON TO 9 PM MDT SUNDAY FOR FORT PECK
LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
238 PM MDT SAT JUL 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
CONVECTIVE ACTIVITY THIS AFTERNOON WILL CONTINUE TO DEVELOP OVER THE
NEXT COUPLE OF HOURS BUT SHOULD DIMINISH PRETTY QUICK WITHOUT THE
SHEAR IN PLACE. HRRR MODEL SHOWING JUST SCATTERED ACTIVITY AT BEST
OVER THE NORTHEASTERN HALF OF THE CWA THIS EVENING.
WITH AN UPPER TROUGH OVER THE EASTERN STATES AND A RIDGE TO OUR
WEST...THE AREA IS UNDER A WEST-NORTHWEST FLOW. A DISTURBANCE...BOTH
AT THE SURFACE AND ALOFT MOVES INTO SOUTHERN SASK LATER
TONIGHT...KEEPING SHOWERS/THUNDERSTORMS GOING OVERNIGHT MAINLY TO
THE NORTHEAST ZONES.
SUNDAY...DISTURBANCE MOVES SOUTHEAST AND THROUGH THE CWA BRINGING AN
INCREASE IN WEST WINDS DURING THE AFTERNOON. THEY SHOULD BE STRONG
ENOUGH TO CAUSE PROBLEMS FOR FORT PECK LAKE FROM NOON UNTIL 9
PM...SO ISSUED A LAKE WIND ADVISORY.
ON MONDAY...BACKDOOR FRONT THAT LIES NW TO SE ACROSS MONTANA SUNDAY
NIGHT HELPS TO FIRE UP THUNDERSTORMS AS A VORT MAX MOVES IN FROM THE
WEST. ACTIVITY MOVES IN FROM THE WEST WITH MORE ACTIVITY EXPECTED
DURING THE EVENING. TFJ
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
AN UPPER LEVEL RIDGE IN THE WEST AND A PERSISTENT UPPER TROUGH
CENTERED OVER NORTHERN QUEBEC WILL MAINTAIN A NORTHWEST FLOW OVER
NORTHEAST MONTANA THROUGH MOST OF THE PERIOD. WEAK EMBEDDED
DISTURBANCES IN THE UPPER FLOW WILL BRING ISOLATED TO SCATTERED
THUNDERSTORMS TO THE REGION THROUGHOUT THE PERIOD.
MONDAY EVENING AND OVERNIGHT GFS SENDS A DISTURBANCE FLOWING
ALONG THE STATIONARY BOUNDARY THAT WILL INITIATE THUNDERSTORMS
ACROSS NEMONT. WITH SOME AGREEMENT FROM THE 00Z EC...WENT AHEAD
AND ADJUSTED POPS TO CHANCE.
TUESDAY THROUGH SATURDAY THE FLUCTUATING STATIONARY BOUNDARY AND
WEAK DISTURBANCES WILL GENERATE A FEW STORMS EACH DAY. THIS IS
REFLECTED IN THE INHERITED GRIDS AND NO CHANGES ARE PLANNED HERE.
SCT
SYNOPTIC SET UP... A LARGE HIGH PRESSURE HEAT DOME IS CENTERED
OVER THE LOWER INTER-MOUNTAIN WEST. A RIDGE SPUR RUNS NORTH OF THIS
DOME INTO BRITISH COLUMBIA. A LARGE TROUGH EXTENDS FROM THE
NORTHERN US PLAINS INTO MANITOBA AND UP THROUGH NUNAVUT. NORTHEAST
MONTANA LIES BETWEEN THESE TWO FEATURES IN A ZONAL TO NORTHWEST
FLOW PATTERN. ANOTHER LARGE TROUGH LIES OFF THE COAST OF BRITISH
COLUMBIA.
MONDAY NIGHT THROUGH THURSDAY NIGHT... NORTHWEST FLOW WILL END UP
ALLOWING HIGH POP CHANCE ACROSS THE NORTHEAST DRYING TOWARD THE
SOUTHWEST. THIS GRADIENT WILL BEGIN A BIT MORE SHARP MONDAY NIGHT
BUT WILL SLOWLY DIFFUSE OUT TOWARD THURSDAY NIGHT AS JETS AND
SHORTWAVES BECOME MORE FUZZY IN TIME. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS DO EXIST ALMOST EVERY PERIOD.
FRIDAY ONWARD... THE PATTERN WILL BECOME A LITTLE MORE PROGRESSIVE
AS THE RIDGE TO THE WEST SETTLES OVER THE MONTANA HIGH PLAINS.
THIS SHOULD EDGE TEMPERATURES UP BUT POPS WILL PROBABLY REMAIN AS
THE ATMOSPHERE BECOMES MORE DESTABILIZED. HOWEVER... QPF IS
EXPECTED TO LOWER AS PLANTS BEGIN TO STRESS FROM PROGRESSIVELY
DRIER HOTTER DAYS AND SOILS FOLLOWED BY THE SURFACE LAYER OF THE
ATMOSPHERE DRY OUT. GAH
&&
.AVIATION...
GENERALLY VFR. HOWEVER A WEAK UPPER LEVEL DISTURBANCE FLOWING
OVER A STATIONARY SURFACE BOUNDARY WILL INITIATE ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS THAT COULD AFFECT ANY OF
THE TAF SITES. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM NOON TO 9 PM MDT SUNDAY FOR FORT PECK
LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
926 PM CDT SUN JUL 21 2013
.SYNOPSIS...
ISSUED AT 333 PM CDT SUN JUL 21 2013
H5 ANALYSIS FROM THIS MORNING...HAS TWO AREAS OF HIGH
PRESSURE ALOFT...THE FIRST OVER NEVADA...AND A SECOND OFF THE
CAROLINA COAST. IN BETWEEN...A TROUGH OF LOW PRESSURE EXTENDED
ACROSS THE SRN PLAINS FROM KANSAS INTO NERN TX. ACROSS THE NRN TIER
OF STATES...INCLUDING THE CENTRAL AND NRN PLAINS...BROAD WEST
NORTHWESTERLY AND WESTERLY FLOW EXTENDED FROM THE PACIFIC NW...INTO
THE CENTRAL AND NRN PLAINS...EWD INTO THE MID ATLANTIC AND NEW
ENGLAND. UPSTREAM OF THE CENTRAL PLAINS...A DECENT SHORTWAVE WAS
NOTED OVER SRN ALBERTA...AND A SECOND STRONGER WAVE OVER NWRN
PORTIONS OF BRITISH COLUMBIA. AT THE SURFACE...A CONVECTIVE INDUCED
MESO HIGH WAS LOCATED OVER SWRN NEBRASKA...WITH DECENT SRLY WINDS
NOTED ACROSS THE PANHANDLE ATTM. AS OF 3 PM CDT...TEMPERATURES
RANGED FROM 84 AT AINWSWORTH...TO 90 AT IMPERIAL.
&&
.UPDATE...
ISSUED AT 921 PM CDT SUN JUL 21 2013
THE HRRR SHOWS THE STORMS ACROSS NW NEB FILLING IN AND BECOMING A
LINE OF TSTMS WHICH SWEEP THE FCST AREA OVERNIGHT. THIS IS
PROBABLY OVERDONE. THE RAP SHOWS NO STORMS AT ALL BUT INDICATES A
20 TO 30 KT LOW LEVEL JET RUNNING DUE NORTH UP THROUGH WRN NEB
TONIGHT. PWAT SHOULD INCREASE TO 1.25 INCHES AND MAYBE MORE
ACCORDING TO THE RAP. SO THE FORECAST HAS BEEN UPDATED FOR SCATTERED
TSTMS WHICH IS A COMPROMISE OF THE HRRR AND RAP MODELS. NOTE THE 18Z
NAM SHOWED ISOLATED STORMS MOVING SOUTHEAST TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 333 PM CDT SUN JUL 21 2013
WEAK WAVE IS MOVING ACROSS EAST CENTRAL WYOMING THIS AFTERNOON. THIS
WAVE WILL BE THE FOCUS FOR SOME ISOLATED THUNDERSTORMS. LACKING SOME
MOISTURE AS DEW PTS IN THE LOWER TO MID 50S. LOW LEVEL JET ALONG THE
FRONT RANGE TONIGHT AND WILL AID IN THUNDERSTORM DEVELOPMENT.
ATMOSPHERE TOOK A BEATING LAST NIGHT AND EARLY THIS MORNING...SO
CONFIDENCE IS LOW ON HOW WIDESPREAD THE COVERAGE WILL BE...HOWEVER
SEVERAL REMNANT BOUNDARIES COULD HELP TO SPARK DEVELOPMENT. SINCE
THERE IS NOT MUCH OF A CU FIELD...AND ONLY ONE CELL HAS GOTTEN GOING
OVER WYOMING...EXPECT COVERAGE TO BE ISOLD. AS FOR TEMPS...THEY
SHOULD COOL BACK INTO THE 60S...ALTHOUGH LOCALLY IN THE WEST A BRIEF
DIP BELOW 60 IS POSSIBLE.
TOMORROW RIDGE REMAINS DOMINATE TO THE SOUTHWEST...WITH MOSTLY SUNNY
SKIES THROUGH MOST OF THE DAY. HIGHS INTO THE LOWER/MID 90S ACROSS
THE SW TO THE UPPER 80S ACROSS N CENTRAL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 333 PM CDT SUN JUL 21 2013
MID RANGE...MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING
CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES...AS TIMING AND
LOCATION REMAIN PROBLEMATIC GIVEN THE NORTHWESTERLY FLOW. FOR MONDAY
NIGHT...MID LEVEL HTS WILL BEGIN TO INCREASE AS HIGH PRESSURE ALOFT
BUILDS EAST OF THE DESERT SOUTHWEST. INCREASED MID LEVEL WAA WILL
RESULT...LEADING TO INCREASED POPS MONDAY NIGHT INTO EARLY TUESDAY.
WILL KEEP POPS AS SLIGHTS ATTM...AS DECENT JET SUPPORT IS FOCUSED
EAST OF THE AREA. A SECONDARY AREA OF MID LEVEL WAA WILL TRACK
ACROSS THE CWA FROM NW TO SE ON TUESDAY INTO TUESDAY EVENING. WILL
HOLD ONTO SLIGHT CHANCES FOR PCPN SINCE THE BEST JET SUPPORT REMAINS
EAST OF THE AREA. BY WEDNESDAY AFTERNOON...BOTH THE NAM AND GFS FORCE
A DECENT SHORTWAVE INTO WRN NEBRASKA LATE IN THE DAY...LIFTING THIS
EAST INTO WEDNESDAY NIGHT. WILL START POPS OFF LOW IN THE WEST...AS
BETTER CHANCES WILL ARRIVE WEDNESDAY NIGHT AS THE FORECAST AREA IS IN
THE RIGHT REAR QUAD OF THE EXITING JET.
LONG RANGE...WEDNESDAY NIGHT THROUGH SUNDAY...ACTIVE WESTERLY AND
NORTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS THE CENTRAL AND
NORTHERN PLAINS INTO THE EXTENDED PERIODS. ATTM...THE BEST CHANCES
FOR RAIN APPEAR TO LIE ON WEDNESDAY NIGHT AND FRIDAY NIGHT AS THE
FORECAST AREA IS IN A FAVORABLE EXIT REGION OF THE H300 JET. HAVE
INCREASED POPS INTO THE 50 PERCENT RANGE FOR WEDNESDAY NIGHT AND
THURSDAY AND WILL KEEP CHANCE POPS GOING INTO THURSDAY NIGHT. THE
EXTENSION OF POPS INTO THURSDAY NIGHT...IS TO ACCOMMODATE THE LATEST
ECMWF WHICH IS 12 HRS SLOWER THAN THE LATEST GFS SOLN. TEMPERATURES
FOR THE WEEK WILL COOL BACK INTO THE 80S...THANKS TO EXPECTED CLOUD
COVER AND SERLY AND ERLY UPSLOPE WINDS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 636 PM CDT SUN JUL 21 2013
VFR IS EXPECTED TONIGHT AND MONDAY. A COLD FRONT...CURRENTLY
MOVING THROUGH ND...SWRN MT AND NERN WY...WILL MOVE THROUGH THE
FCST AREA OVERNIGHT AND BECOME STATIONARY ACROSS SWRN NEB MONDAY
AFTN. THE FRONT COULD BE THE FOCUS FOR ISOLATED STRONG OR SEVERE TSTMS
AFTER 21Z MONDAY FROM ROUGHLY KBBW TO KLBF...KOGA AND KIML. NOTE
ISOLATED TSTMS MAY FORM ALONG THE FRONT TONIGHT AS IT MOVES
THROUGH THE FCST AREA BUT THESE STORMS SHOULD BE VERY MARGINAL.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...MASEK
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
256 PM CDT SAT JUL 20 2013
.SYNOPSIS...
ISSUED AT 253 PM CDT SAT JUL 20 2013
THE H5 ANALYSIS THIS MORNING...HAS AN ACTIVE NW FLOW
PATTERN ACROSS THE NRN CONUS. HIGH PRESSURE WAS ANCHORED ACROSS THE
CENTRAL VALLEY OF CA...WITH A PERSISTENT BERMUDA HIGH PRESENT ACROSS
THE WESTERN ATLANTIC. A BROAD TROUGH OF LOW PRESSURE EXTENDED FROM
NRN QUEBEC INTO THE MID ATLANTIC STATES. ACROSS THE NRN ROCKIES AND
CENTRAL PLAINS...NUMEROUS SHORTWAVES WERE EMBEDDED IN THE NWRLY
FLOW. ONE OVER NWRN WYOMING...AND A SECOND OVER THE IDAHO PANHANDLE.
ANOTHER DISTURBANCE WAS NOTED OVER NWRN IA AS WELL. AT THE
SURFACE...SHOWERS AND THUNDERSTORMS HAVE CONTINUED ACROSS NORTHERN
NEBRASKA THIS MORNING AND EARLY THIS AFTERNOON...ALONG A WEAK
SURFACE BOUNDARY. TEMPERATURES AS OF 2 PM CDT RANGED FROM 68 IN RAIN
COOLED AIR AT ONEILL...TO 87 AT OGALLALA...IMPERIAL AND NORTH PLATTE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 253 PM CDT SAT JUL 20 2013
SCATTERED THUNDERSTORMS THIS AFTERNOON ARE EXPECTED TO DEVELOP OVER
THE NEBRASKA PANHANDLE AND NORTHWEST NEBRASKA AND COALESCE INTO A
CONVECTIVE SYSTEM BY EARLY THIS EVENING. WITH THE DEEP SHEAR VECTORS
DIAGONAL TO THE LOW LEVEL BOUNDARY...IT APPEARS TO FAVOR THE
DEVELOPMENT OF A LINEAR CONVECTIVE SYSTEM. ACCORDING TO THE SHORT
RANGE HRRR AND RAP13...THE SYSTEM WILL AFFECT A LARGE PART OF THE
SANDHILLS AND SOUTHWEST NEBRASKA BY 01Z AND FINALLY CLEARING CENTRAL
NEBRASKA BY 09Z. THEY DO INDICATE SOME LINGERING SHOWERS AND
THUNDERSTORMS EVEN INTO EARLY SUNDAY.
INSTABILITY CONTINUES OVER WESTERN NEBRASKA SUNDAY AND THERE IS A
CHANCE OF ANOTHER CONVECTIVE SYSTEM DEVELOPING IN SOUTH DAKOTA AND
NORTHWEST NEBRASKA LATE SUNDAY MORNING OR EARLY AFTERNOON...THEN
CROSSING WESTERN NEBRASKA THROUGH THE AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 253 PM CDT SAT JUL 20 2013
MID RANGE...SUNDAY NIGHT THROUGH TUESDAY...A FAIRLY ACTIVE PATTERN
WILL CONTINUE INTO TUESDAY...THANKS TO NWLY FLOW AND THE PRESENCE OF
EMBEDDED SHORTWAVES WITHIN THAT FLOW. BEGINNING SUNDAY
NIGHT...ANOTHER UPPER LEVEL DISTURBANCE WILL TRACK FROM THE CENTRAL
AND NORTHERN ROCKIES...ACROSS WESTERN AND NORTH CENTRAL NEBRASKA.
CONVECTION WILL BE ONGOING BY SUNDAY AFTERNOON AND IS EXPECTED TO
IMPACT MOST OF THE FORECAST AREA DURING THE EVENING AND OVERNIGHT
HOURS. ATTM...WILL PAINT THE HIGHEST POPS IN THE CENTRAL AND
SOUTHWESTERN CWA...AS THESE LOCATIONS WILL SEE THE BEST DEEP LAYER
SHEAR OF 30 TO 40 KTS. SHEAR IN THE NERN ZONES WILL RUN 10 TO 20 KTS
SUNDAY EVENING...SO ANY TSRAS IN THESE AREAS WILL BE FEW AND FAR
BETWEEN. WILL CONTINUE MENTION OF THUNDERSTORMS IN THE FORECAST
OVERNIGHT IN THE SOUTHWESTERN ZONES AS THERE ARE INDICATIONS OF THE
DEVELOPMENT OF A LOW LEVEL JET...WHICH BECOMES FOCUSED ACROSS SWRN
AND CENTRAL NEBRASKA OVERNIGHT SUNDAY NIGHT. CONVECTION ALONG WITH
THE EXITING DISTURBANCE...WILL FORCE A FRONTAL BOUNDARY THROUGH THE
FORECAST AREA ON MONDAY...STALLING THIS FEATURE ACROSS CENTRAL AND
EASTERN NEBRASKA MONDAY EVENING. ONCE AGAIN...UPPER LEVEL ENERGY
WILL ENTER THE CENTRAL PLAINS FROM THE ROCKIES LATE IN THE DAY
MONDAY...LEADING TO THE DEVELOPMENT OF THUNDERSTORMS. THERE IS SOME
DISAGREEMENT AS TO WHERE THE UPPER LEVEL ENERGY WILL TRACK DURING
THIS PERIOD SO CONFIDENCE IN LOCATION OF POPS IS LACKING ATTM.
DECIDED TO CONFINE POPS INVOF OF THE FRONTAL BOUNDARY...IE...EASTERN
CWA FOR MONDAY NIGHT. ON TUESDAY...EASTERLY WINDS WILL BECOME
SOUTHERLY BY AFTERNOON AS HIGH PRESSURE DRIFTS EAST INTO THE UPPER
MIDWEST. THE FRONTAL BOUNDARY WILL WASH OUT WHILE NORTHWESTERLY FLOW
ALOFT CONTINUES. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL
TRACK ACROSS THE REGION TUESDAY AFTERNOON AND TUESDAY NIGHT AS
ANOTHER UPPER LEVEL DISTURBANCE TRACKS FROM THE CENTRAL AND NORTHERN
ROCKIES ONTO THE CENTRAL PLAINS.
LONG RANGE...TUESDAY NIGHT THROUGH SATURDAY...A FAIRLY ACTIVE
PATTERN WILL CONTINUE INTO THE EXTENDED PERIODS WITH ABUNDANT LOW
LEVEL MOISTURE AND PERSISTENT WESTERLY AND NORTHWESTERLY FLOW ALOFT.
NUMEROUS SHORTWAVES WILL TRACK ACROSS THE CENTRAL ROCKIES ACROSS THE
CENTRAL PLAINS THROUGH THE PERIOD...LEADING TO A GOOD CHANCE FOR
PRECIPITATION DURING THE PERIOD. TEMPERATURES WILL BE SEASONAL WITH
HIGHS IN THE 80S AND LOWS IN THE UPPER 50S AND LOWER 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 253 PM CDT SAT JUL 20 2013
SCATTERED THUNDERSTORMS ARE EXPECTED THIS EVENING OVER A LARGE PART
OF CENTRAL AND WESTERN NEBRASKA. WITH STORMS FORMING INTO A LINE
LATE THIS AFTERNOON...THE PROBABILITY OF THUNDERSTORMS AT ANY ONE
SITE IS LIKELY TO BE 50 PERCENT OR HIGHER. AS A RESULT THUNDER IS IN
THE TERMINAL FORECASTS FOR VTN AND LBF THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...SPRINGER
LONG TERM...CLB
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1248 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1247 PM CDT SAT JUL 20 2013
UPDATED HWO IS OUT AND HAS OUR THOUGHTS THIS AFTN. ADDITIONAL
TSTMS COULD DEVELOP AT ANY TIME. WE/VE BEEN WATCHING A DECENT
STORM LEAVE WEBSTER FOR THAYER COUNTY WITH SOME TORRENTIAL
RAINFALL. THE TSTM CLUSTERS OVER THE PANHANDLE AND SANDHILLS ARE
EXPECTED TO INCREASE IN COVERAGE/INTENSITY AND THAT ACTIVITY
SHOULD ARRIVE HERE TNGT.
UPDATE ISSUED AT 1107 AM CDT SAT JUL 20 2013
THE INITIAL COMPOSITE OUTFLOW BOUNDARY CONTS DROPPING STEADILY S
AT 22 KTS AND WILL ARRIVE AT THE KS BORDER AROUND 1215 PM. SCT
SHWRS WERE DEVELOPING ATOP THIS OUTFLOW AND THIS POTENTIAL IS
EXPECTED TO CONT DESPITE THE SEEMINGLY UNFAVORABLE ENVIRONMENT.
VIS SATPIX SHOWED ANOTHER OUTFLOW BOUNDARY /FROM THE TSTMS HEADING
INTO NE NEB/ THAT WILL MOVE INTO THE NRN FRINGE OF THE FCST AREA
SHORTLY /ORD-GREELEY/.
THE OAX SOUNDING WAS VERY DRY BELOW 700 MB FROM OVERNGT
SUBSIDENCE. HOWEVER...THE OUTFLOW IS CLEARLY ENOUGH TO INITIATE
SHWRS WITH EMBEDDED THUNDER. SO THIS REALLY COMPLICATES THE
SITUATION TODAY...AND LOWERS CONFIDENCE IN HOW THINGS WILL
DEVELOP/EVOLVE. REGIONAL 88D WIND PROFILES SHOW DEEP E-NE FLOW UP
TO 9K FT...WHICH WOULD BE ENUF TO INITIATE SHWRS/THUNDER BASED ON
THE OAX SOUNDING. GLD AND TOP HAVE MORE SHALLOW S FLOW...WHERE
MSTR IS HIGHER. SO WOULD EXPECT HIGHER MSTR TO ADVECT N AND BE
INTERCEPTED BY THE OUTFLOW. HOWEVER...ANOTHER NEGATIVE FACTOR IS
THE EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY. THE INHIBITED
HEATING MAKES MODELED CAPE QUESTIONABLE. EVEN THE NE LOW-MID LVL
FLOW OVER NEB IS NOT BEING CAPTURED BY THE MODELS /THEY CURRENTLY
HAVE SE WINDS AND MAINTAIN THEM/. SO FCST VALUES OF DEEP LAYER
SHEAR ARE LESS CERTAIN.
SO FOR NOW BELIEVE THE HIGHEST FOCUS FOR SVR TSTM POTENTIAL SHOULD
BE IN SUNNIEST AREAS /CURRENTLY S AND W OF THE TRI-CITIES/.
THE FCST AREA WILL BE IN THE RRQ OF A 60 KT ULJ. THIS SHOULD
PROVIDE SUFFICIENT SHEAR FOR THE STRONGEST/TALLEST STORMS AND
WOULD ESTIMATE MLCAPE OF 1500-2000 J/KG OF MLCAPE IN THE SUNNIEST
AREAS.
STORM MOVEMENT FOR INDIVIDUAL/NON-MULTICELL STORMS WILL BE EAST
AROUND 10 KTS OVER NRN KS AND AROUND 20 KTS OVER S-CNTRL NEB.
UPDATE ISSUED AT 944 AM CDT SAT JUL 20 2013
AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND
ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING
OUTFLOW BOUNDARY AS EMANATED FROM THESE CLUSTERS AND IS
APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE
THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL
EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT
THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD...VERY DRY. WILL
HAVE MORE LATER ON THIS.
OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/
WX/POPS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1247 PM CDT SAT JUL 20 2013
THIS AFTN: VFR BUT ISOLATED SHWRS/TSTMS WILL BE NEARBY WITH
POCKETS OF MVFR/IFR VSBYS IN +RA. WATCH FOR SHORT-TERM AMENDMENTS
AS WE WILL PROVIDE ADDITIONAL DETAILS IF THE TERMINAL IS
THREATENED. NE WINDS WILL CONT 10-20 KTS BUT THIS IS DUE TO TSTM
OUTFLOW AND NOT PART OF THE BROADER FLOW. SO IT REMAINS UNCERTAIN
WHEN THE WIND RETURNS TO E OR SE.
TNGT: VFR BUT A 1-2 HR PERIOD OF TSTMS IS POSSIBLE. JUST NOT SURE
ON EXACT TIMING OR OCCURRENCE. FUTURE TAFS MAY NEED TO INCLUDE
MORE DEFINITIVE TIME FRAME. WIND SHOULD BECOME SE BELOW 10 KTS.
THERE IS A SLGT CHANCE OF IFR FOG IS SKIES CLEAR AND WINDS TURN
LGT BEHIND TSTMS.
SUN THRU 18Z: IFR FOG POSSIBLE TO START...BUT IT/S NOT IN THE TAF
UNTIL WE SEE IF TSTMS DEVELOP. WINDS WILL BE LGT AND VARIABLE.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: MEDIUM
WIND CONFIDENCE: LOW
WX CONFIDENCE: LOW
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1107 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1107 AM CDT SAT JUL 20 2013
THE INITIAL COMPOSITE OUTFLOW BOUNDARY CONTS DROPPING STEADILY S
AT 22 KTS AND WILL ARRIVE AT THE KS BORDER AROUND 1215 PM. SCT
SHWRS WERE DEVELOPING ATOP THIS OUTFLOW AND THIS POTENTIAL IS
EXPECTED TO CONT DESPITE THE SEEMINGLY UNFAVORABLE ENVIRONMENT.
VIS SATPIX SHOWED ANOTHER OUTFLOW BOUNDARY /FROM THE TSTMS HEADING
INTO NE NEB/ THAT WILL MOVE INTO THE NRN FRINGE OF THE FCST AREA
SHORTLY /ORD-GREELEY/.
THE OAX SOUNDING WAS VERY DRY BELOW 700 MB FROM OVERNGT
SUBSIDENCE. HOWEVER...THE OUTFLOW IS CLEARLY ENOUGH TO INITIATE
SHWRS WITH EMBEDDED THUNDER. SO THIS REALLY COMPLICATES THE
SITUATION TODAY...AND LOWERS CONFIDENCE IN HOW THINGS WILL
DEVELOP/EVOLVE. REGIONAL 88D WIND PROFILES SHOW DEEP E-NE FLOW UP
TO 9K FT...WHICH WOULD BE ENUF TO INITIATE SHWRS/THUNDER BASED ON
THE OAX SOUNDING. GLD AND TOP HAVE MORE SHALLOW S FLOW...WHERE
MSTR IS HIGHER. SO WOULD EXPECT HIGHER MSTR TO ADVECT N AND BE
INTERCEPTED BY THE OUTFLOW. HOWEVER...ANOTHER NEGATIVE FACTOR IS
THE EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY. THE INHIBITED
HEATING MAKES MODELED CAPE QUESTIONABLE. EVEN THE NE LOW-MID LVL
FLOW OVER NEB IS NOT BEING CAPTURED BY THE MODELS /THEY CURRENTLY
HAVE SE WINDS AND MAINTAIN THEM/. SO FCST VALUES OF DEEP LAYER
SHEAR ARE LESS CERTAIN.
SO FOR NOW BELIEVE THE HIGHEST FOCUS FOR SVR TSTM POTENTIAL SHOULD
BE IN SUNNIEST AREAS /CURRENTLY S AND W OF THE TRI-CITIES/.
THE FCST AREA WILL BE IN THE RRQ OF A 60 KT ULJ. THIS SHOULD
PROVIDE SUFFICIENT SHEAR FOR THE STRONGEST/TALLEST STORMS AND
WOULD ESTIMATE MLCAPE OF 1500-2000 J/KG OF MLCAPE IN THE SUNNIEST
AREAS.
STORM MOVEMENT FOR INDIVIDUAL/NON-MULTICELL STORMS WILL BE EAST
AROUND 10 KTS OVER NRN KS AND AROUND 20 KTS OVER S-CNTRL NEB.
UPDATE ISSUED AT 944 AM CDT SAT JUL 20 2013
AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND
ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING
OUTFLOW BOUNDARY AS EMANATED FROM THESE CLUSTERS AND IS
APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE
THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL
EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT
THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD...VERY DRY. WILL
HAVE MORE LATER ON THIS.
OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/
WX/POPS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 529 AM CDT SAT JUL 20 2013
THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING
ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL
THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND
SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON
HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND
WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND
ANY THUNDERSTORMS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
944 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 944 AM CDT SAT JUL 20 2013
AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND
ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING
OUTFLOW BOUNDARY AS EMINATED FROM THESE CLUSTERS AND IS
APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE
THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL
EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT
THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD. WILL HAVE MORE LATER
ON THIS.
OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/
WX/POPS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 529 AM CDT SAT JUL 20 2013
THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING
ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL
THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND
SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON
HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND
WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND
ANY THUNDERSTORMS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
552 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 529 AM CDT SAT JUL 20 2013
THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING
ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL
THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND
SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON
HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND
WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND
ANY THUNDERSTORMS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
414 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1250 AM CDT SAT JUL 20 2013
EXPECT THE WIND WILL REMAIN LIGHT AND OUT OF THE SOUTHEAST THROUGH
THE MORNING...BUT SHOULD INCREASE WITH DIURNAL HEATING AND MAY
EVEN BE A BIT GUSTY AT TIMES THIS AFTERNOON WITH SOME VEERING TO
SOUTH SOUTHEAST. THE WIND WILL AGAIN DIE DOWN BY EARLY EVENING
ONCE WE LOSE THE AFTERNOON HEATING AND SHOULD BACK TO A SOUTHEAST
WIND. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THEREFORE...HAVE
INTRODUCED VICINITY THUNDERSTORMS INTO THE TAF FOR THE EVENING
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
256 AM MDT SAT JUL 20 2013
.DISCUSSION...
NOT MUCH CHANGE TO THE GOING FORECAST. AN ACTIVE WEEKEND REMAINS ON
TAP WITH HIGH PWATS...SLOW MOVING STORMS AND THUS...INCREASED FLASH
FLOOD POTENTIAL. PREVIOUS SHIFT ISSUED A FLASH FLOOD WATCH...AND
THIS REMAINS IN GOOD SHAPE. ONE CAVEAT FOR TODAY WILL BE THE AMOUNT
OF DEBRIS CLOUDS FROM LAST NIGHTS/ONGOING CONVECTION ACROSS THE
AREA. IF THE CLOUD COVER LINGERS...THIS WILL LIMIT INSTABILITY THIS
AFTERNOON AND WOULD THEREBY REDUCE RAIN RATES. MODELS MAY BE HINTING
AT THIS A BIT...AS INSTABILITY DOES NOT LOOK TO BE AS STRONG AS
MODELS WERE SUGGESTING 24 HOURS AGO. NONETHELESS...WITH 140-180
PERCENT OF NORMAL PWATS AND NEAR ZERO STORM MOTION...ANY ONE STORM
THAT DEVELOPS COULD POSE FLOODING PROBLEMS. IN ADDITION TO THE HIGH
TERRAIN...REMNANT BOUNDARIES WILL BE THE FOCUS FOR TODAYS
CONVECTION. SIMILAR STORY IN STORE FOR SUNDAY...THOUGH MORE STABLE
AIR STILL LOOKS TO MIGRATE INTO THE EASTERN PLAINS.
MORE DRY AIR WILL WORK INTO NORTHERN AND EASTERN NM ON MONDAY AS THE
UPPER HIGH BEGINS TO MIGRATE EASTWARD FROM NEVADA. THE MOST UNSTABLE
AREA WILL BE ACROSS THE WEST CENTRAL AND SOUTHWEST MOUNTAINS...WHERE
HEAVY RAIN POTENTIAL WILL CONTINUE. BY TUESDAY...THE UPPER HIGH WILL
BE CENTERED OVER WEST CENTRAL COLORADO. WITH THE HIGH EVEN
CLOSER...SUBSIDENCE UNDER THE HIGH WILL LIMIT CONVECTIVE COVERAGE
FURTHER...THOUGH THE FAR WEST WILL HAVE THE BEST POTENTIAL FOR
CONTINUED STORMS.
BY WEDNESDAY...MODELS ARE NOW SUGGESTING THE UPPER HIGH WILL BE
CENTERED OVER FAR NE NM. ISOLD/SCT STORMS WILL REMAIN POSSIBLE
ACROSS THE FAR WEST...BUT GENERALLY QUIET CONDITIONS ARE EXPECTED
ELSEWHERE. BOTH THE ECMWF AND THE GFS TAKE THE UPPER HIGH INTO
TEXAS/OKLAHOMA BY THURSDAY NOW...WHICH OPENS THE DOOR FOR THE
TRADITIONAL MONSOON PLUME. THAT SAID...BY FRIDAY AFTERNOON...THE
HIGH LOOKS TO ELONGATE AND ANY HIGH CENTER BECOMES QUIET MUDDLED.
THEN ON SATURDAY...BOTH MODELS ARE SUGGESTING A BACK DOOR COLD FRONT
WILL ROLL DOWN THE PLAINS AND INCREASE POTENTIAL FOR STORMS ACROSS
THE EAST. STAY TUNED...AS CONFIDENCE REMAINS FAIRLY LOW BEYOND
WEDNESDAY.
34
&&
.FIRE WEATHER...
A VERY ACTIVE FRIDAY WILL BE FOLLOWED BY ANOTHER ACTIVE WEATHER DAY
TODAY. HOWEVER...ONGOING CONVECTION AND CLOUD COVER MAY BE SLOW TO
CLEAR THIS MORNING SO TODAYS ROUND OF SHOWERS AND STORMS COULD GET
A LATER START THAN ON FRIDAY. POTENTIAL FOR HEAVY RAIN AND FLASH
FLOODING PRETTY HIGH TODAY INTO TONIGHT ESPECIALLY OVER RECENT BURN
SCARS AND PLACES THAT HAD HEAVY RAIN AND SOME FLOODING FRIDAY.
HIGH PRESSURE TO OUR NORTHWEST WILL GRADUALLY BUILD TOWARD AND OVER
NEW MEXICO SUNDAY INTO WEDNESDAY. A SLOW TREND DOWNWARD IN SHOWERS
AND STORMS WILL BE THE CASE...WITH THE KEY WORD BEING SLOW...AS LOW
LEVELS TO REMAIN MOIST WHILE MID AND UPPER LEVELS GRADUALLY DRY
OUT.
MODELS TAKE CENTER OF HIGH PRESSURE A LITTLE EAST OF NEW MEXICO FOR
THE END OF NEXT WEEK...WHILE AN EASTERLY WAVE DRIFTING NORTHEAST FROM
MEXICO MAY BEGIN TO IMPACT THE SOUTHWEST PORTIONS OF THE STATE. THIS
WOULD ALLOW FOR A MORE CLASSIC MONSOONAL SURGE OF MOISTURE FOR THE
WEST THURSDAY AND FRIDAY.
MODELS DIVERGE BY NEXT WEEKEND WITH THE GFS KEEPING THE HIGH CENTER
TO OUR EAST WHILE THE EUROPEAN BUILDS THE HIGH BACK OVER AND A
LITTLE WEST OF THE STATE. BOTH MODELS THOUGH BRING COPIOUS AMOUNTS
OF RAIN FOR NEXT WEEKEND AS THE EUROPEAN HAS A BACK DOOR FRONT
BLASTING INTO NEW MEXICO WHILE THE GFS HAS THE EARLIER MENTIONED
EASTERLY WAVE COMING UP THROUGH AZ AND WESTERN NM...WITH A WEAKER
PUSH FROM THE BACK DOOR COLD FRONT.
HIGH TEMPERATURES WILL GRADUALLY WARM THROUGH MIDWEEK WHILE MINIMUM
RH VALUES LOWER. NIGHTTIME RECOVERIES WILL REMAIN MOSTLY GOOD TO
EXCELLENT ASIDE FROM FAIR MOST NIGHTS IN THE NORTHWEST. VENTILATION
WILL BE FAIR OR BETTER FOR THE MOST PART EXCEPT FOR SOME POOR RATES
IN THE NORTHWEST TODAY...RIO GRANDE VALLEY SUNDAY AND WEST TUESDAY.
CHJ
&&
.AVIATION...
06Z TAF CYCLE
A BROAD AREA OF SLOW MOVING SHOWERS AND THUNDERSTORMS OVER NE NM IS
EXPECTED TO DRIFT SLOWLY S AND SSW FOR THE REMAINDER OF THE NIGHT.
MEANWHILE...MODELS DEPICT CONVECTION IN THE W CENTRAL AND SW MTS
GRADUALLY DIMINISHING OR EXITING WESTWARD. HOWEVER...THESE CELLS LOOK
STRONG ENOUGH TO LAST THROUGH AT LEAST 09Z. THE HRRR MODEL...WHICH HAS
BEEN DOING PRETTY GOOD LATELY...ALSO DEPICTS A SMALL CLUSTER OF
CELLS SHIFTING FROM NEAR KSAF SWWD THROUGH THE KABQ/KAEG AREA LATE
TONIGHT. ANOTHER ROUND OF SCT-NMRS STORMS IS EXPECTED SATURDAY
AFTN AND EVENING...WITH THE POTENTIAL FOR MORE HEAVY RAIN...MT
OBSCURATIONS AND HAIL. WITH THE 500 MB HIGH PRESSURE CENTER OVER
NV...THE CONVECTION SHOULD CONTINUE TO TRACK TOWARD THE S...SW AND
W ACROSS NM.
44
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 91 65 93 66 / 30 30 20 30
DULCE........................... 84 52 87 54 / 50 50 40 40
CUBA............................ 83 54 86 54 / 50 50 50 50
GALLUP.......................... 83 59 85 59 / 50 50 40 40
EL MORRO........................ 79 53 79 53 / 60 50 50 50
GRANTS.......................... 82 58 83 58 / 40 50 40 40
QUEMADO......................... 81 56 81 57 / 60 60 50 50
GLENWOOD........................ 82 57 83 58 / 40 40 50 40
CHAMA........................... 79 48 80 50 / 70 60 50 40
LOS ALAMOS...................... 79 60 82 62 / 50 50 50 40
PECOS........................... 73 58 77 60 / 50 60 50 40
CERRO/QUESTA.................... 78 54 80 55 / 60 50 40 40
RED RIVER....................... 71 44 75 44 / 70 60 50 40
ANGEL FIRE...................... 73 43 77 43 / 70 60 50 40
TAOS............................ 81 53 86 54 / 50 50 40 30
MORA............................ 72 54 78 55 / 60 60 50 40
ESPANOLA........................ 83 59 86 60 / 40 40 40 30
SANTA FE........................ 79 59 83 61 / 50 60 50 40
SANTA FE AIRPORT................ 82 60 86 62 / 50 50 40 30
ALBUQUERQUE FOOTHILLS........... 84 65 88 68 / 60 60 40 40
ALBUQUERQUE HEIGHTS............. 85 67 89 70 / 50 50 30 30
ALBUQUERQUE VALLEY.............. 86 65 90 68 / 40 40 30 30
ALBUQUERQUE WEST MESA........... 86 65 90 67 / 40 40 30 40
LOS LUNAS....................... 88 64 89 67 / 40 40 20 30
RIO RANCHO...................... 87 65 91 67 / 40 40 30 30
SOCORRO......................... 92 65 93 66 / 30 30 20 30
SANDIA PARK/CEDAR CREST......... 83 59 86 61 / 60 60 50 40
TIJERAS......................... 81 60 84 63 / 50 60 50 40
MORIARTY/ESTANCIA............... 80 58 83 59 / 50 50 40 40
CLINES CORNERS.................. 79 58 82 60 / 40 50 40 40
GRAN QUIVIRA.................... 80 58 82 60 / 40 40 40 30
CARRIZOZO....................... 82 61 84 64 / 30 30 30 20
RUIDOSO......................... 73 53 74 56 / 50 30 40 30
CAPULIN......................... 79 56 84 58 / 50 50 20 20
RATON........................... 83 57 89 58 / 50 40 30 30
SPRINGER........................ 83 58 88 59 / 40 50 30 20
LAS VEGAS....................... 79 57 83 57 / 50 50 30 30
CLAYTON......................... 87 65 93 66 / 30 30 10 10
ROY............................. 82 63 86 64 / 40 30 10 20
CONCHAS......................... 88 67 92 69 / 20 20 10 10
SANTA ROSA...................... 87 65 91 68 / 20 20 10 10
TUCUMCARI....................... 92 69 95 71 / 20 20 10 10
CLOVIS.......................... 87 64 89 65 / 10 10 5 10
PORTALES........................ 88 65 89 65 / 10 10 5 5
FORT SUMNER..................... 88 67 90 68 / 10 10 10 10
ROSWELL......................... 90 67 92 69 / 10 10 5 10
PICACHO......................... 84 60 86 63 / 20 20 10 10
ELK............................. 77 57 79 59 / 40 30 20 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES...
NMZ501>529.
&&
$$
34
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1151 PM MDT FRI JUL 19 2013
.AVIATION...
06Z TAF CYCLE
A BROAD AREA OF SLOW MOVING SHOWERS AND THUNDERSTORMS OVER NE NM IS
EXPECTED TO DRIFT SLOWLY S AND SSW FOR THE REMAINDER OF THE NIGHT.
MEANWHILE...MODELS DEPICT CONVECTION IN THE W CENTRAL AND SW MTS
GRADUALLY DIMINISHING OR EXITING WESTWARD. HOWEVER...THESE CELLS LOOK
STRONG ENOUGH TO LAST THROUGH AT LEAST 09Z. THE HRRR MODEL...WHICH HAS
BEEN DOING PRETTY GOOD LATELY...ALSO DEPICTS A SMALL CLUSTER OF
CELLS SHIFTING FROM NEAR KSAF SWWD THROUGH THE KABQ/KAEG AREA LATE
TONIGHT. ANOTHER ROUND OF SCT-NMRS STORMS IS EXPECTED SATURDAY
AFTN AND EVENING...WITH THE POTENTIAL FOR MORE HEAVY RAIN...MT
OBSCURATIONS AND HAIL. WITH THE 500 MB HIGH PRESSURE CENTER OVER
NV...THE CONVECTION SHOULD CONTINUE TO TRACK TOWARD THE S...SW AND
W ACROSS NM.
44
&&
.PREV DISCUSSION...725 PM MDT FRI JUL 19 2013...
BASED ON RADAR TRENDS TODAY AND EXPECTED HEAVY/TORRENTIAL RAIN
POTENTIAL THROUGH THE WEEKEND...DECIDED TO HOIST A FLASH FLOOD
WATCH FOR CENTRAL AND WESTERN NM. PWAT VALUES WILL COME UP EVEN
A LITTLE HIGHER FOR THE REGION AND STEERING FLOW WILL CONTINUE
TO WEAKEN. CONSIDERING IMPACTS FROM STORMS TODAY WE EXPECT VERY
SIMILAR CONDITIONS THROUGH AT LEAST SUNDAY EVENING. FFA ALREADY
ON THE STREET AND PRODUCT UPDATES FOLLOWING SHORTLY.
GUYER
.PREV DISCUSSION...258 PM MDT FRI JUL 19 2013...
ROBUST ROUND OF THUNDERSTORMS ON THE UPTREND AS OF 3PM...MOVING
WSW FROM THE NORTHERN MOUNTAINS AND NE HIGHLANDS/PLAINS. A REPORT
OF 1.54 INCHES IN LESS THAN ONE HOUR CAME IN FROM NEAR 10 MILES
SOUTH OF SANTA FE...SO THESE STORMS ARE CERTAINLY CAPABLE OF
PRODUCING LOCALLY HEAVY RAINFALL. THE 12Z KABQ PWAT WAS 1.27
INCHES...WHICH IS 147 PERCENT OF NORMAL AND CLOSE TO +2 STANDARD
DEVIATIONS ABOVE NORMAL. IN ADDITION TO THE JUICY ATMOSPHERE
OVERHEAD...STORM MOTIONS IS 10 MPH OR LESS WHICH ADDS TO THE
LOCALLY HEAVY RAINFALL THREAT. STORMS APPROACHING THE ABQ METRO
FROM THE NE WILL CERTAINLY HAVE A PRIMED AIRMASS TO WORK OVER...
WITH THE 20Z LAPS ANALYSIS SHOWING SURFACE BASED CAPES AROUND 2000
J/KG AND LIFTED INDICES BETWEEN -4 AND -5C. MAIN IMPACT PERIOD FOR
THE ABQ METRO WILL BE FROM 330 TO 530PM MDT. SHOWERS AND
THUNDERSTORMS WILL PERSIST INTO THE EVENING HOURS...BUT SHOULD
DIMINISH SHORTLY AFTER MIDNIGHT WITH NO SUNRISE SURPRISES SATURDAY
MORNING.
SATURDAY WILL BE SIMILAR OVERALL WITH WELL ABOVE NORMAL PWATS...
BUT SLOWER STORM MOTION TO THE WEST OR SOUTHWEST. LOCALLY HEAVY
RAINFALL AMOUNTS OF 1 TO 2 INCHES WILL BE POSSIBLE AGAIN...
ESPECIALLY OVER THE MOUNTAIN ZONES. SUNDAY WILL BE A TAD
WARMER/DRIER OVERALL AS PRESSURE HEIGHTS INCREASE WITH THE UPPER
HIGH OVER NEVADA RIDGING INTO COLORADO AND NORTHERN NM. SUNDAY`S
CROP OF THUNDERSTORMS WILL LIKELY HUG THE TERRAIN A BIT MORE AS
WELL WITH EVEN LIGHTER STEERING FLOW.
THE FORECAST TRENDS AND CHALLENGES BEYOND MONDAY HAVE NOT CHANGED
THIS FORECAST CYCLE. A GRADUAL TEMPERATURE UPTREND AND CONVECTIVE
DOWNTREND IS FORECAST NEXT WEEK AS THE UPPER HIGH MOVES SLOWLY ESE
ACROSS NM AND INTO TEXAS. SOME DIFFERENCES ARE STILL SHOWING UP IN
THE PLACEMENT OF THE UPPER HIGH CENTROID BY FRIDAY OF NEXT
WEEK...WITH THE ECMWF STILL SHOWING IT EAST OF NM. SO AT SOME
POINT LATE NEXT WEEK...OR POSSIBLY DELAYED UNTIL THE
WEEKEND...TEMPERATURES WILL TREND BACK DOWN AND RAIN CHANCES WILL
TREND BACK UP AS A MORE TRADITIONAL MONSOON PATTERN SETS UP. THAT
SAID...LOW FORECAST CONFIDENCE BEYOND WEDNESDAY AT THIS TIME.
11
.FIRE WEATHER...
ISOLATED SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE TONIGHT WITH
A JUICY AIRMASS IN PLACE AND SOME WEAK ATMOSPHERIC LIFT REMAINING
OVER THE AREA. BACK DOOR COLD FRONT OVER NE PLAINS AND HIGHLANDS
WILL KEEP A FEW STRONG STORMS GOING THERE UNTIL AROUND MIDNIGHT
ALONG WITH ISOLATED SHOWERS THROUGH THE EARLY MORNING. PARTIAL
CLEARING MAY INHIBIT OVERNIGHT RELATIVE HUMIDITY RECOVERIES SLIGHTLY
BUT STILL EXPECTING VERY GOOD TO EXCELLENT RECOVERY VALUES MOST
PLACES BY EARLY MORNING SATURDAY WITH WIDESPREAD WETTING RAINS.
ANOTHER ACTIVE TO VERY ACTIVE DAY IN STORE SATURDAY WITH THE UPPER
LEVEL WEATHER PATTERN CHANGING LITTLE AND PLENTY OF MOISTURE IN
PLACE...POSSIBLY INCREASING SOMEWHAT MORE WITH A WEAK TO MODERATE
SOUTHERLY SURFACE FLOW DEVELOPING.
PREVIOUS WEATHER PREDICTION MODEL INDICATIONS WERE THAT A DOWNTREND
IN CONVECTION WOULD BEGIN SUNDAY AS THE DEEPER MOISTURE HEADED
WESTWARD INTO ARIZONA. LATEST DATA...HOWEVER...SUGGESTS THAT THIS
MAY NOT BE THE CASE. WHILE SOME DRIER AIR ALOFT BEGINS TO FILTER IN
FROM THE NORTHEAST...PLENTY OF LOW AND MID LEVEL MOISTURE EXPECTED
TO CONTINUE TO PUSH UP FROM SOUTH FROM DECAYING CONVECTIVE COMPLEXES
OVER NORTHERN OLD MEXICO SUNDAY MORNING.
ANOTHER ACTIVE DAY IN STORE MONDAY AS THE UPPER HIGH MOVES LITTLE
AND PLENTY OF LOW LEVEL MOISTURE LEFT IN PLACE TO RECYCLE. AT THIS
POINT IN TIME...TUESDAY APPEARS TO BE THE FIRST OF SEVERAL DOWN DAYS
AS VERY DRY AIR ALOFT BEGINS TO MOVE IN FROM THE EAST/SE.
GENERAL TREND OF THE MEDIUM RANGE MODELS IS TO SHIFT THE FOUR
CORNERS HIGH SLOWLY EASTWARD WEDNESDAY NIGHT INTO
THURSDAY...ALLOWING FOR A CLASSIC SOUTHERLY MONSOONAL FLOW. BOTH
ECMWF AND GFS INDICATING THAT AN EASTERLY WAVE MAY ALSO GET INTO THE
MIX...MOVING UP INTO SW AZ THURSDAY NIGHT AND FRIDAY...ENHANCING THE
DEEP SOUTHERLY MONSOONAL FLOW OVER NM TOWARD THE END OF THE WORK
WEEK.
33
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES...
NMZ501>529.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1032 PM EDT SUN JUL 21 2013
.SYNOPSIS...
FAIRLY SEASONABLE TEMPERATURES AND A NORMAL SCATTERING OF AFTERNOON
STORMS ARE EXPECTED THE NEXT SEVERAL DAYS...COMPLIMENTS OF BERMUDA
HIGH PRESSURE. A COLD FRONT DROPPING CLOSE TO THE REGION ON THURSDAY
WILL STALL AND KEEP THE WEATHER A BIT MORE UNSETTLED.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1030 PM SUNDAY...WATER VAPOR IMAGERY SHOWS AN ANTICYCLONIC
(CLOCKWISE) SPIN OVER THE EASTERN CAROLINAS. MODELS ARE STRUGGLING
TO CONSISTENTLY LOCATE REGIONS OF CYCLONIC CURVATURE THAT MAY BE
HELPING SUSTAIN CLUSTERS OF SHOWERS AND T-STORMS. AGAIN REFERENCING
WATER VAPOR IMAGERY IT APPEARS ONE UPPER DISTURBANCE LIES ACROSS
CENTRAL NORTH CAROLINA INTO WEST-CENTRAL SOUTH CAROLINA...WHILE A
SECOND MORE QUIESCENT DISTURBANCE LIES OFF THE GEORGIA AND SOUTHERN
SOUTH CAROLINA COAST.
THE AIRMASS REMAINS SEASONABLY WARM...BUT MOISTURE CONTENT AS
MEASURED BY PRECIPITABLE WATER IS VERY HIGH: 2.2 INCHES. LAPSE RATES
ARE NOT PARTICULARLY STEEP BUT ARE JUST LARGE ENOUGH THROUGH THE
900-600 MB LAYER TO PROMOTE GOOD UPDRAFT ACCELERATION. IR SATELLITE
SHOWS CLOUD TOP TEMPERATURES MAINTAINING LARGE AREAS COLDER THAN
-60C. BASED ON RECENT TRENDS AND THE LAST SEVERAL HRRR RUNS (WHICH
HAVEN`T BEEN BAD THIS EVENING) THE CONVECTION ACROSS THE SC PEE DEE
REGION SHOULD LARGELY DISSIPATE WITHIN THE NEXT 2-3 HOURS WHILE NEW
CONVECTION DEVELOPS CLOSER TO THE COAST...ESPECIALLY THE NC COAST.
AFTER 2 AM MOST OF THE CONVECTION SHOULD EXIT THE LANDMASS AND MOVE
EASTWARD INTO THE OCEAN.
HIGH-REFLECTIVITY (>50DBZ) CORES HAVE SO FAR REMAINED VERY LOW IN
THE STORMS...BARELY ABOVE THE FREEZING LEVEL. THIS IS CORRELATED
WITH EFFICIENT HEAVY RAIN PRODUCTION BUT NOT WITH SEVERE WEATHER.
SINCE CELL MOVEMENT REMAINS SLOW FROM THE WEST FLOODING WILL BE THE
PRIMARY THREAT TO WATCH FOR THE NEXT SEVERAL HOURS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...COPIOUS MOISTURE REMAINS IN PLACE ON MONDAY WITH
PRECIPITABLE WATER STILL ABOVE 2 INCHES. WHILE WIDESPREAD CLOUD
COVER INHIBITED INSOLATION AND THUS CONVECTIVE COVERAGE TODAY THIS
APPEARS A LITTLE LESS LIKELY MONDAY.FCST SOUNDINGS LESS INDICATIVE
OF WIDESPREAD SC EARLY IN THE DAY SO EXPECT BETTER HEATING AND THUS
COVERAGE OF STORMS. ITS HARD TO PIN DOWN ANY FAVORED AREAS FOR
HIGHER POPS...ABUT A LATE DAY UPPER VORT AND SFC TROUGH MAY FOCUS
ACTIVITY OVER WESTERN ZONES EVEN AS A LARGER SCALE DIURNAL WANING IS
UNDERWAY. A STRONGER VORT WILL SCOOT BY TO OUR NORTH ON
TUESDAY...PERHAPS AROUND MIDDAY. IN ITS WAKE WILL BE A SUPPRESSING
EFFECT ON CONVECTION AND SOME 20-30 POPS SEEM ALL THAT IS WARRANTED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...PATTERN ALOFT REMAINS AMPLIFIED THROUGH THE
PERIOD WITH 5H TROUGHING OVER THE EAST COAST AND RIDGING OUT WEST.
THIS MAINTAINS ACTIVE WEATHER ACROSS THE SOUTHEAST WITH PIEDMONT
TROUGH AND SEA BREEZE BEING THE FOCUS ON WED. FROM THU ON WEAK COLD
FRONT MOVES INTO THE REGION BUT STALLS WITH FLOW ALOFT BECOMING
PARALLEL TO THE SURFACE BOUNDARY. HAVE A HARD TIME BELIEVING THE
FRONT WILL MAKE IT TO THE COAST FOR ANY LENGTH OF TIME WITH THE 5H
TROUGH AXIS REMAINING WEST OF THE AREA. WEAK WAVES DEVELOPING ON THE
FRONT WILL BRIEFLY PUSH THE BOUNDARY TO THE COAST BEFORE ALLOWING IT
TO RETURN INLAND. IN ADDITION TO NUDGING THE FRONT EAST OR WEST
THESE WAVES SHOULD HELP GENERATE AND ENHANCE CONVECTION. TIMING THE
FEATURES AT THIS POINT IS DIFFICULT AT BEST SO WILL MAINTAIN CHANCE
POP THROUGH THE FORECAST PERIOD.
FRONT WILL SLOWLY DISSIPATE DURING THE SECOND HALF OF THE
PERIOD...EVENTUALLY MERGING WITH THE PIEDMONT TROUGH. NEXT WEEKEND A
SHORTWAVE MOVING INTO THE MS VALLY INDUCES A SURFACE LOW WHICH THEN
LIFTS NORTHEAST THROUGH THE OH VALLEY. COLD FRONT ASSOCIATED WITH
THE LOW MOVES INTO THE CAROLINAS LATE IN THE PERIOD. STRONGER 5H
TROUGH SUGGESTS THIS FRONT MAY HAVE A BETTER CHANCE OF REACHING OR
MOVING OFF THE COAST. AT THE VERY LEAST IT WILL RESULT IN AN
INCREASE IN PRECIP CHANCES FOR THE WEEKEND...ESPECIALLY SUN.
DAILY CONVECTION AND CLOUD COVER WILL KEEP HIGHS NEAR TO SLIGHTLY
BELOW CLIMO WHILE SOUTHERLY FLOW...MOISTURE AND LEFT OVER DEBRIS
CLOUD KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...DUE TO SCATTERED NATURE OF SHOWER ACTIVITY WILL ELECT TO
INDICATE VCSH IN TAFS THIS EVENING AT ALL TERMINALS ALTHOUGH THE
CHANCE OF ANY TERMINAL BEING AFFECTED IS RATHER SMALL. SHOWERS WILL
GRADUALLY DISSIPATE BY MIDNIGHT LOCAL OVER LAND THEN BEGIN TO
DEVELOP IN THE COASTAL WATERS.
TEMPO MVFR CIGS WILL BE POSSIBLE AT THE COASTAL TERMINALS TERMINALS
THIS EVENING. MVFR CIGS WILL BECOME MORE LIKELY BY MIDNIGHT LOCAL AT
THE COASTAL TERMINALS. VSBYS SHOULD DROP TO MVFR IN BR AT KFLO/KLBT
BY MIDNIGHT LOCAL WITH SCATTERED IFR STRATUS. AFTER MIDNIGHT THERE
IS INCREASING CONFIDENCE OF IFR CIGS AT ALL TERMINALS.
ANY IFR CIGS SHOULD RISE TO MVFR BY 14Z WITH VFR DEVELOPING LATE
MORNING INTO EARLY AFTERNOON. SHOULD BE A GOOD CHANCE OF VCSH AT THE
COASTAL TERMINALS BY NOON LOCAL WITH VCTS DEVELOPING AT KFLO/KLBT
WITH THE APPROACH OF AN UPPER IMPULSE.
EXTENDED OUTLOOK...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED THROUGH THURSDAY...WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR POSSIBLE. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1030 PM SUNDAY...ASIDE FROM BUMPING UP SEAS BY A FOOT IN SPOTS
BASED ON LATEST OBSERVATIONS...NO SIGNIFICANT CHANGES ARE NEEDED TO
THE FORECAST. IF CONDITIONS WERE ANY WORSE WE WOULD BE FORCED TO
APPEND AN EXERCISE CAUTION HEADLINE TO THE FORECAST...PARTICULARLY
ALONG THE BRUNSWICK COUNTY COAST. PREVIOUS DISCUSSION FROM 730 PM
FOLLOWS...
WINDS FINALLY SURGED UP IN THE LAST FEW HOURS BUT ARE STILL WELL
BELOW ADVISORY THRESHOLDS. RECENT GUSTS INCLUDE 21 KNOTS AT THE
FRYING PAN SHOALS BUOY...NORTH MYRTLE BEACH...AND OAK ISLAND...20
KNOTS ON BALD HEAD ISLAND...AND 19 KNOTS IN GEORGETOWN. THESE
STRONGER SOUTHWEST WINDS MAY CONTINUE THROUGH 11 PM OR MIDNIGHT
BEFORE A LANDBREEZE PRODUCES MUCH LIGHTER WEST-SOUTHWEST WINDS NEAR
THE BEACHES...SPREADING OUT AWAY FROM THE COAST OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...WEAK WAVE OF LOW PRESSURE NEAR DELMARVA WILL
VEER LOCAL FLOW SLIGHTLY TO A MORE WESTERLY DIRECTION THAN THE
TYPICAL SW FOR PART OF MONDAY. LATER IN THE DAY SW FLOW GETS
ESTABLISHED WITH ABOUT A 5KT INC IN SPEED. THIS TREND WILL CONTINUE
INTO MONDAY NIGHT BUT NOT TO WHERE CAUTIONARY HEADLINES WARRANTED AS
SEAS NOT EXPECTED TO BUILD QUITE ENOUGH WITHIN 20NM BORDER.
PIEDMONT TROUGHINESS DEVELOPS LATER FRIDAY AND SHOULD MAINTAIN
SLIGHTLY HIGHER WIND SPEEDS THAN WHAT SEASONABLE...15 TO 20KT MOST
ZONES. A LITTLE LIGHTER FLOW OVER SRN LEGS WHICH SHOULD PREVENT 5 FT
SEAS OFF GTOWN.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD
WITH WATERS IN BETWEEN BERMUDA HIGH AND PIEDMONT TROUGH/WEAK COLD
FRONT. WINDS AND SEAS WILL BE HIGHEST EARLY IN THE PERIOD. GRADIENT
RELAXES AS FRONT/TROUGH MOVE CLOSER TO THE COAST AND WEAK SURFACE
WAVES DEVELOP ON THE BOUNDARY. SPEEDS WILL BE 10 TO 15 KT WED THEN
DECREASE TO AROUND 10 KT FOR THU AND FRI. SEAS WILL FALL FROM 3 TO 4
FT ON WED TO AROUND 2 FT FRI.
&&
.TIDES/COASTAL FLOODING...
AS OF 1030 PM SUNDAY...THE CAPE FEAR RIVER CRESTED AT 6.23 FEET MLLW
AT DOWNTOWN WILMINGTON THIS EVENING. THIS IS SIMILAR TO LAST
NIGHT...AND IS THE RESULT OF THE ASTRONOMICAL HIGH TIDE ASSOCIATED
WITH THIS MONTH`S FULL MOON...PLUS A LARGE AMOUNT OF WATER DRAINING
DOWN THE CAPE FEAR RIVER SYSTEM FROM EXCESSIVE RAINS OVER THE PAST
FEW WEEKS UPSTREAM. UNFORTUNATELY IT LOOKS LIKE AT LEAST THE NEXT
TWO EVENING HIGH TIDES ALONG THE CAPE FEAR WILL PROBABLY INDUCE MORE
MINOR FLOODING.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 8 PM TO 11 PM EDT THIS EVENING FOR
NCZ107.
MARINE...NONE.
&&
$$
SYNOPSIS...MBB
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...III
AVIATION...MRR
COASTAL FLOODING...TRA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
840 PM EDT SUN JUL 21 2013
.SYNOPSIS...
A SURFACE TROUGH WILL PERSIST OVER THE REGION...IN A MOIST AIR
MASS...AT LEAST THROUGH THE MIDDLE OF THE WEEK...AS A TROUGH IN THE
UPPER LEVELS OF THE ATMOSPHERE MOVES INTO THE MID ATLANTIC AND THE
CAROLINAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 PM SUNDAY...
THE LATEST SURFACE ANALYSIS CONTINUED TO SHOW THE SURFACE TROUGH
OVER THE NORTHWEST PIEDMONT TOWARD THE UPSTATE OF SOUTH CAROLINA...
AND ALONG THIS TROUGH WHERE BETTER SURFACE CONVERGENCE
EXISTED...SCATTERED SHOWERS AND THUNDERSTORMS WERE OCCURRING OR
DEVELOPING. DOWNDRAFT CAPE AND LOW-LEVEL SHEAR REMAINED LIMITED...
BUT THE LATEST SPC MESOANALYSIS SHOWED MIXED-LAYER CAPE AROUND
2000J/KG NEAR THE SURFACE TROUGH. SCATTERED SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE TO MOVE INTO THE WESTERN PIEDMONT
DURING THE LATE AFTERNOON...AND THE HRRR WRF HAS BEEN CONSISTENT
SHOWING SCATTERED SHOWERS AND THUNDERSTORMS SPREADING EAST TO ABOUT
U.S. 1 THROUGH 01Z BEFORE GENERALLY DIMINISHING. THROUGHOUT THE
DAY...THE RUC HAS BEEN PERSISTENT MAINTAINING SOME CHANCES FOR
SHOWERS ACROSS THE SANDHILLS AND CENTRAL AND SOUTHERN COASTAL
PLAIN...WHERE THE GFS HAS SLIGHTLY GREATER 850MB LIFT OVERNIGHT AND
WHERE THAT MODEL ALSO FORECASTS A RELATIVE MAXIMUM OF POTENTIAL
VORTICITY MOVING ACROSS THE AREA. GIVEN THIS...IT IS POSSIBLE THAT
SOME OF THE SHOWERS OVER WESTERN NORTH CAROLINA OR THE UPSTATE OF
SOUTH CAROLINA WILL PERSIST AS THEY DRIFT EAST NEAR AND JUST NORTH
OF THE SOUTH CAROLINA BORDER OVERNIGHT. WILL KEEP A SLIGHT CHANCE OF
SHOWERS FOR THE OVERNIGHT HOURS AFTER MIDNIGHT MAINLY EAST OF A LINE
FROM ABOUT KRWI TO KFAY. UNDER A PARTLY-TO-MOSTLY CLOUDY SKY...WITH
AREAS OF CLOUDS COURTESY OF DEEP CONVECTION AND THEN SOME HIGH
CLOUDS MOVING IN FROM THE WEST LATE...OVERNIGHT LOWS WILL AGAIN BE
70 TO 75 DEGREES. THE SREF SHOWS THE POTENTIAL FOR LOW CLOUDS TO BE
LESS THAN THE LAST COUPLE OF MORNINGS...HOWEVER...SOME OF THE
GUIDANCE MAINTAINS THE CHANCES FOR LOW CLOUDS PARTICULARLY TOWARD
KRDU...KFAY...AND KRWI...LESS TOWARD THE TRIAD. IF LOW CLOUDS INDEED
OCCUR...IT IS CURRENTLY THOUGHT THEY SHOULD BE LESS WIDESPREAD THAN
WHAT HAS OCCURRED THIS WEEKEND.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 310 PM SUNDAY...
MONDAY AND MONDAY NIGHT...
BOTH THE NAM AND THE GFS GRADUALLY MOVE THE WEAK UPPER LOW OVER THE
SOUTHERN MISSISSIPPI RIVER SLOWLY NORTHEAST...AND INDEED THE LATEST
WATER VAPOR IMAGERY SHOWS THIS WEAK LOW MOVING MORE INTO
MISSISSIPPI. BY THE TIME THE UPPER LOW GETS TO CENTRAL NORTH
CAROLINA...IT IS FORECAST TO WEAKEN FURTHER...AND FORECAST
PARAMETERS OF INSTABILITY...SHEAR...AND MOISTURE ARE SIMILAR TO WHAT
HAS RECENTLY OCCURRED. 850MB THETA-E IS PERSISTENT AROUND 340K AS
WELL...CURRENTLY SUGGESTIVE OF LITTLE OVERALL CHANGE IN ANTICIPATED
CONDITIONS. WITH THE WEAK UPPER LOW THE GFS DOES FORECAST A VERY
MODEST 35KT JETLET INTO CENTRAL NORTH CAROLINA AT 300MB MONDAY
AFTERNOON...BUT WITH MIXED-LAYER CAPE FROM ABOUT 1000J/KG TO
2000J/KG AND DOWNDRAFT CAPE REMAINING 500J/KG OR LESS...THINK
CONDITIONS WILL BE SIMILAR TO THE LAST COUPLE OF DAYS...MOSTLY
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...HIGHER
CHANCES RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA TOWARD THE
WESTERN PIEDMONT AS THE WEAK LOW OR ITS REMNANTS APPROACHES...AND A
PARTLY SUNNY DAY ON AVERAGE WITH HIGHS AROUND 90. MONDAY
NIGHT...BOTH THE NAM AND THE GFS FORECAST ALMOST A WEAK PSEUDO FRONT
OR STRONG TROUGH MOVING INTO THE WESTERN PART OF CENTRAL NORTH
CAROLINA WITH DIMINISHING PRECIPITABLE WATER VALUES BEHIND IT TO
NEAR 1.5 INCHES LATE TOWARD THE YADKIN RIVER AND DEW POINTS FALLING
INTO THE UPPER 60S. BUFR SOUNDINGS BECOME SOMEWHAT MORE STABLE
OVERNIGHT IN CENTRAL NORTH CAROLINA...AND QPF IS CERTAINLY
LIMITED...BUT WITH THE APPROACH OF THIS TROUGH WILL MAINTAIN A
SLIGHT CHANCE OF A SHOWER THROUGH THE OVERNIGHT HOURS. OVERNIGHT
LOWS ABOUT A DEGREE OR TWO COOLER THAN WHAT SHOULD OCCUR
TONIGHT...BUT STILL 70 TO 75...MAYBE AN UPPER 60S LOW OR TWO TOWARD
THE FAR WESTERN PIEDMONT. -DJF
TUESDAY THROUGH WEDNESDAY NIGHT...
HEIGHTS WILL CONTINUE TO SLOWLY FALL ALOFT TUESDAY AND WEDNESDAY AS
A BROAD TROUGH BECOMES ESTABLISHED OVER THE EASTERN US.
MEANWHILE...A COLD FRONT TO OUR NORTH WILL SLOWLY SINK SOUTHEAST AND
EVENTUALLY MERGE WITH RELATIVELY STRONG LARGE SCALE LOW LEVEL TROUGH
EAST OF THE MOUNTAINS. ENERGY CURRENTLY MOVING OUT OF
MONTANA/WYOMING IS FORECAST MOVE THROUGH THE BASE OF THE UPPER
TROUGH TUESDAY...FOLLOWED BY ANOTHER SHORTWAVE ON WEDNESDAY.
HOWEVER...THE TIMING AND STRENGTH OF THESE WEAK WAVES AND OTHER
DISTURBANCES WITHIN THE FLOW ARE STILL NEBULOUS. FORECAST SOUNDINGS
DO INDICATE A BIT MORE WESTERLY FLOW ON TUESDAY...WITH PW
TEMPORARILY DROPPING TO 1.5" OR LESS OVER THE WESTERN CWA AND THE
INTRUSION OF DRIER MID LEVEL AIR. HOWEVER...WITH THE MEAN TROUGH
AXIS STILL WEST OF OUR AREA... PROFILES MOISTEN BACK UP ON WEDNESDAY
WITH MORE ENERGY APPROACHING FROM THE WEST. UNDER CYCLONIC FLOW
ALOFT AND MODERATE INSTABILITY...WE SHOULD SEE SCATTERED STORMS
BOTH DAYS BUT BETTER COVERAGE OVER THE EAST IN THE VICINITY OF
BETTER LOW LEVEL CONVERGENCE AND DEEP MOISTURE. HIGHS 88-92. LOWS IN
UPPER 60S AND LOWER 70S. -BLS
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 310 PM SUNDAY...
THE LAST IN A SERIES OF UPPER DISTURBANCES IS FORECAST TO PASS
THROUGH THE UPPER TROUGH ON THURSDAY...WITH MODELS HAVING TRENDED
DRIER FRIDAY AND SATURDAY AS THE REMNANT FRONTAL ZONE OVER THE EAST
COAST STATES SLIDES LITTLE FURTHER EAST TOWARD THE COAST. THERE
SHOULD BE LESS COVERAGE IF STORMS THURSDAY AS THE MID LEVELS BEGIN
TO DRY OUT...BUT THE PASSAGE OF THE MEAN TROUGH AXIS AND SLIGHTLY
STRONGER MID-LEVEL FLOW MAY STILL SUPPORT SOME STRONG TO SEVERE
STORMS. LOWER DEWPOINTS BEHIND THE FRONT/TROUGH SHOULD LIMIT
CONVECTION FRIDAY AND SATURDAY...PARTICULARLY IN THE WEST.
THICKNESSES FALL AS WELL...WITH HIGHS LIKELY TO BE MORE IN THE MID
AND UPPER 80S.
THE BROAD EASTERN US TROUGH IS EXPECTED TO RELOAD BY THE END OF THE
WEEKEND AS ENERGY CONTINUES TO ROTATE AROUND AN UPPER LOW NORTH OF
THE HUDSON BAY. BOTH THE ECMWF AND GFS SHOW A MODEST LOW PRESSURE
SYSTEM MOVING OFF THE FRONT RANGE SATURDAY AND MOVING TOWARD THE
MID-ATLANTIC STATES BY SUNDAY/MONDAY...THOUGH WPC/S EXTENDED
DISCUSSION RAISES SOME DOUBT IN THE STRENGTH OF SUCH A FEATURE.
NONETHELESS...THERE IS ENOUGH AGREEMENT IN THE MODELS TO HAVE MEDIUM
CONFIDENCE IN TEMPS SLIGHTLY BELOW NORMAL OVER THE WEEKEND AND
ANOTHER CHANCE OF STORMS BY THE END OF THE WEEKEND.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 845 PM SUNDAY...
THERE IS A CHANCE OF THUNDERSTORMS MOSTLY EAST OF THE KINT/KGSO
TERMINALS THIS EVENING. OTHERWISE... GENERALLY VFR CONDITIONS
EXPECTED UNTIL LATER TONIGHT WHEN LOW STRATUS WILL AGAIN BE LIKELY
FROM KFAY TO KRDU TO KRWI BETWEEN 09Z-12Z OR SO. THIS WILL BURN OFF
MONDAY MORNING BY AROUND 15Z-16Z... WITH ANOTHER CHANCE OF
THUNDERSTORMS DURING THE AFTERNOON AND EVENING AT ALL TAF SITES.
TUESDAY THROUGH FRIDAY... GENERALLY VFR CONDITIONS EXPECTED OUTSIDE
OF THE CHANCE OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS MAINLY
IN THE EAST ON TUESDAY AND WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF/BLS
LONG TERM...BLS
AVIATION...PWB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
729 PM EDT SUN JUL 21 2013
.SYNOPSIS...
FAIRLY SEASONABLE TEMPERATURES AND A NORMAL SCATTERING OF AFTERNOON
STORMS ARE EXPECTED THE NEXT SEVERAL DAYS...COMPLIMENTS OF BERMUDA
HIGH PRESSURE. A COLD FRONT DROPPING CLOSE TO THE REGION ON THURSDAY
WILL STALL AND KEEP THE WEATHER A BIT MORE UNSETTLED.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 730 PM SUNDAY...UNLIKE LAST NIGHT WHERE CONVECTION FELL APART
VERY QUICKLY DURING THE EVENING...WE SHOULD SEE SHOWER AND EMBEDDED
T-STORM ACTIVITY PERSIST THROUGH THE EVENING HOURS...DRIVEN BY UPPER
LEVEL DISTURBANCES EMBEDDED IN THE WESTERLY FLOW ALOFT. EARLIER
SYNOPTIC MODELS PLACED ONE SIGNIFICANT UPPER DISTURBANCE ACROSS THE
CAPE FEAR REGION OF SE NORTH CAROLINA CURRENTLY...BUT LOOKING AT
WATER VAPOR IMAGERY AND RADAR SHOWS THIS PROBABLY IS NOT CORRECT.
THE 21Z RUC APPEARS TO HAVE A BETTER HANDLE ON THE SITUATION AND
PLACES THE BEST 500 MB VORTICITY ALONG AN AXIS FROM CHARLOTTE TO
SOUTH OF COLUMBIA...MATCHING RADAR IMAGERY MUCH BETTER. THIS
DISTURBANCE WILL HAVE ACCESS TO SUFFICIENT INSTABILITY OVER THE NEXT
4 HOURS TO CONTINUE PRODUCING SHOWERS AND EMBEDDED T-STORMS...WITH
THE BULK OF THE CONVECTION SHIFTING EAST AND OFFSHORE AROUND
MIDNIGHT. BESIDES ADJUSTING POP/SKY/WIND FIELDS TO BETTER FIT THE
RUC/HRRR IDEAS OVER THE NEXT 4-6 HOURS...NO SIGNIFICANT CHANGES HAVE
BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
SCATTERED MODERATE AND ISOLATED HEAVY SHOWERS AND TSTMS WERE
TRACKING ENE AROUND 15 MPH ACROSS THE FORECAST AREA AT 3PM.
SQUELCHED SURFACE HEATING HAS THUS FAR RESULTED IN LOWER SURFACE
BASED CAPES AND VIRTUALLY NO SEA BREEZE CONVERGENCE UP TO THIS POINT
WHICH HAS PLAYED A SIGNIFICANT ROLE IN REDUCED CONVECTIVE COVERAGE
AND INTENSITY CONSIDERING THE AVAILABILITY OF ABUNDANT COLUMN
MOISTURE. AS A RESULT ONLY LOW-END RAINFALL ACCUMULATIONS HAVE
OCCURRED SO FAR GIVEN PRECIPITABLE WATERS IN EXCESS OF 2".
NOT EXPECTING A GREAT DEAL OF CHANGE TO RADAR TRENDS THROUGH THE
AFTERNOON ALTHOUGH WE MAY SEE A BIT MORE HEAVIER CELLS PICK UP A
BIT AS MID AFTERNOON JULY SUNSHINE POKES THROUGH AT TIMES...AIDING
IN LOCALIZED POCKETS OF GREATER LOW-LEVEL INSTABILITY. STILL THINK
LOSS OF HEATING INTO EARLY EVENING WILL LESSEN COVERAGE OVERALL.
THERE IS ONE SHORT-WAVE IMPULSE NOTED IN VAPOR ANIMATIONS THAT
COULD SUSTAIN ACTIVITY INTO TONIGHT PRESENTLY OVER GEORGIA HEADING
INTO SOUTH CAROLINA. FOR THIS REASON AND THE FACT THAT WE HAVE
A MODERATELY BUOYANT AND WET ATMOSPHERE WHICH MAY EASILY BE
TRIGGERED BY OUTFLOWS...WILL SUSTAIN MENTIONABLE POPS INTO THE
TONIGHT PERIOD. BELIEVE WE MAY SEE 1200-1800 FOOT STRATUS CLOUDS
OVERNIGHT AND HAVE OPTED FOR THE SLIGHTLY WARMER SIDE OF THE
GUIDANCE ENVELOPE...MAINLY MID 70S MOST LOCATIONS AND UPPER 70S
ALONG THE IMMEDIATE COAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...COPIOUS MOISTURE REMAINS IN PLACE ON MONDAY WITH
PRECIPITABLE WATER STILL ABOVE 2 INCHES. WHILE WIDESPREAD CLOUD
COVER INHIBITED INSOLATION AND THUS CONVECTIVE COVERAGE TODAY THIS
APPEARS A LITTLE LESS LIKELY MONDAY.FCST SOUNDINGS LESS INDICATIVE
OF WIDESPREAD SC EARLY IN THE DAY SO EXPECT BETTER HEATING AND THUS
COVERAGE OF STORMS. ITS HARD TO PIN DOWN ANY FAVORED AREAS FOR
HIGHER POPS...ABUT A LATE DAY UPPER VORT AND SFC TROUGH MAY FOCUS
ACTIVITY OVER WESTERN ZONES EVEN AS A LARGER SCALE DIURNAL WANING IS
UNDERWAY. A STRONGER VORT WILL SCOOT BY TO OUR NORTH ON
TUESDAY...PERHAPS AROUND MIDDAY. IN ITS WAKE WILL BE A SUPPRESSING
EFFECT ON CONVECTION AND SOME 20-30 POPS SEEM ALL THAT IS WARRANTED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...PATTERN ALOFT REMAINS AMPLIFIED THROUGH THE
PERIOD WITH 5H TROUGHING OVER THE EAST COAST AND RIDGING OUT WEST.
THIS MAINTAINS ACTIVE WEATHER ACROSS THE SOUTHEAST WITH PIEDMONT
TROUGH AND SEA BREEZE BEING THE FOCUS ON WED. FROM THU ON WEAK COLD
FRONT MOVES INTO THE REGION BUT STALLS WITH FLOW ALOFT BECOMING
PARALLEL TO THE SURFACE BOUNDARY. HAVE A HARD TIME BELIEVING THE
FRONT WILL MAKE IT TO THE COAST FOR ANY LENGTH OF TIME WITH THE 5H
TROUGH AXIS REMAINING WEST OF THE AREA. WEAK WAVES DEVELOPING ON THE
FRONT WILL BRIEFLY PUSH THE BOUNDARY TO THE COAST BEFORE ALLOWING IT
TO RETURN INLAND. IN ADDITION TO NUDGING THE FRONT EAST OR WEST
THESE WAVES SHOULD HELP GENERATE AND ENHANCE CONVECTION. TIMING THE
FEATURES AT THIS POINT IS DIFFICULT AT BEST SO WILL MAINTAIN CHANCE
POP THROUGH THE FORECAST PERIOD.
FRONT WILL SLOWLY DISSIPATE DURING THE SECOND HALF OF THE
PERIOD...EVENTUALLY MERGING WITH THE PIEDMONT TROUGH. NEXT WEEKEND A
SHORTWAVE MOVING INTO THE MS VALLY INDUCES A SURFACE LOW WHICH THEN
LIFTS NORTHEAST THROUGH THE OH VALLEY. COLD FRONT ASSOCIATED WITH
THE LOW MOVES INTO THE CAROLINAS LATE IN THE PERIOD. STRONGER 5H
TROUGH SUGGESTS THIS FRONT MAY HAVE A BETTER CHANCE OF REACHING OR
MOVING OFF THE COAST. AT THE VERY LEAST IT WILL RESULT IN AN
INCREASE IN PRECIP CHANCES FOR THE WEEKEND...ESPECIALLY SUN.
DAILY CONVECTION AND CLOUD COVER WILL KEEP HIGHS NEAR TO SLIGHTLY
BELOW CLIMO WHILE SOUTHERLY FLOW...MOISTURE AND LEFT OVER DEBRIS
CLOUD KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...DUE TO SCATTERED NATURE OF SHOWER ACTIVITY WILL ELECT TO
INDICATE VCSH IN TAFS THIS EVENING AT ALL TERMINALS ALTHOUGH THE
CHANCE OF ANY TERMINAL BEING AFFECTED IS RATHER SMALL. SHOWERS WILL
GRADUALLY DISSIPATE BY MIDNIGHT LOCAL OVER LAND THEN BEGIN TO
DEVELOP IN THE COASTAL WATERS.
TEMPO MVFR CIGS WILL BE POSSIBLE AT THE COASTAL TERMINALS TERMINALS
THIS EVENING. MVFR CIGS WILL BECOME MORE LIKELY BY MIDNIGHT LOCAL AT
THE COASTAL TERMINALS. VSBYS SHOULD DROP TO MVFR IN BR AT KFLO/KLBT
BY MIDNIGHT LOCAL WITH SCATTERED IFR STRATUS. AFTER MIDNIGHT THERE
IS INCREASING CONFIDENCE OF IFR CIGS AT ALL TERMINALS.
ANY IFR CIGS SHOULD RISE TO MVFR BY 14Z WITH VFR DEVELOPING LATE
MORNING INTO EARLY AFTERNOON. SHOULD BE A GOOD CHANCE OF VCSH AT THE
COASTAL TERMINALS BY NOON LOCAL WITH VCTS DEVELOPING AT KFLO/KLBT
WITH THE APPROACH OF AN UPPER IMPULSE.
EXTENDED OUTLOOK...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED THROUGH THURSDAY...WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR POSSIBLE. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 730 PM SUNDAY...WINDS FINALLY SURGED UP IN THE LAST FEW HOURS
BUT ARE STILL WELL BELOW ADVISORY THRESHOLDS. RECENT GUSTS INCLUDE
21 KNOTS AT THE FRYING PAN SHOALS BUOY...NORTH MYRTLE BEACH...AND
OAK ISLAND...20 KNOTS ON BALD HEAD ISLAND...AND 19 KNOTS IN
GEORGETOWN. THESE STRONGER SOUTHWEST WINDS MAY CONTINUE THROUGH 11
PM OR MIDNIGHT BEFORE A LANDBREEZE PRODUCES MUCH LIGHTER
WEST-SOUTHWEST WINDS NEAR THE BEACHES...SPREADING OUT AWAY FROM THE
COAST OVERNIGHT. NO OTHER SIGNIFICANT CHANGES ARE NECESSARY TO THE
FORECAST. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
BECAUSE INLAND HEATING WAS PREVENTED BY THE EXTENSIVE CLOUD
COVER...THE SEA BREEZE NEVER QUITE GOT CRANKING AND COASTAL WATER
WINDS HAVE REMAINED AROUND 15 KNOTS WHILE SEAS EVEN OUT BEYOND 20NM
MILES HAVE DAMPENED TO 4 FEET. THEREFOR WILL DROP THE EXERCISE
CAUTION HEADLINE WITH THE AFTERNOON ISSUANCE OF THE CWF. SEAS WILL
BE COMPRISED OF S WAVE 3 FT AT 6 SECONDS AND SE WAVES 1-2 FEET EVERY
8-9 SECONDS. A FEW TSTMS OR HEAVY SHOWERS MAY IMPACT THE WATERS
THROUGH THE NEAR TERM PERIOD...LOCALLY REDUCING VSBYS AND IMPARTING
CLOUD TO SEA STRIKES.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...WEAK WAVE OF LOW PRESSURE NEAR DELMARVA WILL
VEER LOCAL FLOW SLIGHTLY TO A MORE WESTERLY DIRECTION THAN THE
TYPICAL SW FOR PART OF MONDAY. LATER IN THE DAY SW FLOW GETS
ESTABLISHED WITH ABOUT A 5KT INC IN SPEED. THIS TREND WILL CONTINUE
INTO MONDAY NIGHT BUT NOT TO WHERE CAUTIONARY HEADLINES WARRANTED AS
SEAS NOT EXPECTED TO BUILD QUITE ENOUGH WITHIN 20NM BORDER.
PIEDMONT TROUGHINESS DEVELOPS LATER FRIDAY AND SHOULD MAINTAIN
SLIGHTLY HIGHER WIND SPEEDS THAN WHAT SEASONABLE...15 TO 20KT MOST
ZONES. A LITTLE LIGHTER FLOW OVER SRN LEGS WHICH SHOULD PREVENT 5 FT
SEAS OFF GTOWN.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD
WITH WATERS IN BETWEEN BERMUDA HIGH AND PIEDMONT TROUGH/WEAK COLD
FRONT. WINDS AND SEAS WILL BE HIGHEST EARLY IN THE PERIOD. GRADIENT
RELAXES AS FRONT/TROUGH MOVE CLOSER TO THE COAST AND WEAK SURFACE
WAVES DEVELOP ON THE BOUNDARY. SPEEDS WILL BE 10 TO 15 KT WED THEN
DECREASE TO AROUND 10 KT FOR THU AND FRI. SEAS WILL FALL FROM 3 TO 4
FT ON WED TO AROUND 2 FT FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 8 PM TO 11 PM EDT THIS EVENING FOR
NCZ107.
MARINE...NONE.
&&
$$
SYNOPSIS...MBB
NEAR TERM...MJC/TRA
SHORT TERM...MBB
LONG TERM...III
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A SURFACE TROUGH OF LOW PRESSURE...IN A MOIST AIR MASS...WILL REMAIN
OVER THE REGION AT LEAST THROUGH THE MIDDLE OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS
MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING...
AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN
PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND
LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS
WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR
A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE
REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN
NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB
TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO
AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE
THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO
KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST
PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND
THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE
EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH
THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS
AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS
PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE
AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS
A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA...
TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE
WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY
NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR
SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN
THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE
HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES
COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A
STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND
SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED
INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS
AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB
THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND
WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN
THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 AM SATURDAY...
SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE
US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND
NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY
MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF
THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF
THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING
NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A
DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND
DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND
SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE
2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH
HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE
STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG
INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED
SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS
COULD RESULT IN LOCALIZED FLOODING.
HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 230 PM SATURDAY...
MONDAY THROUGH TUESDAY NIGHT...
EARLY THIS WEEK...BROAD TROUGHING WILL CONTINUE TO EVOLVE OVER THE
EASTERN US... WHILE A QUASI-STATIONARY FRONTAL ZONE NEAR THE
MASON-DIXON LINE REMAINS TO OUR NORTH. A PAIR OF WEAK UPPER
DISTURBANCES SHOULD IMPACT THE AREA AS MONDAY AND TUESDAY AS THE
UPPER TROUGH BEGINS A SLOW AMPLIFICATION. THE FIRST DISTURBANCE
WILL BE THE REMNANTS OF A WEAK UPPER LOW CURRENTLY OVER
LOUISIANA...WHICH DYNAMIC TROPOPAUSE MAPS SHOW LIFTING ACROSS
CENTRAL AND WESTERN NC MONDAY AFTERNOON. THE SECOND AND LIKELY
STRONGER DISTURBANCE IS ASSOCIATED WITH ENERGY MAKING ITS WAY
ACROSS INTO THE NORTHERN PLAINS. CONFIDENCE IN THE TIMING/IMPACTS
OF EITHER OF THESE DISTURBANCES IS ONLY MEDIUM AT DAYS 3 AND 4...BUT
THEY WOULD LIKELY ENHANCE CONVECTION IN WHAT WILL BE A MODERATELY
UNSTABLE AIRMASS WITH DEWPOINTS IN THE LOWER 70S AND PW BACK UP TO
NEAR 2 INCHES. WILL INDICATE THE HIGHEST POPS OVER THE WESTERN
PIEDMONT MONDAY AND OVER THE COASTAL PLAIN ON TUESDAY. WHILE STRONG
STORMS WILL BE POSSIBLE...WEAK FLOW ALOFT DOESN`T SUPPORT A
SIGNIFICANT SEVERE THREAT. HIGHS IN THE UPPER 80S AND AROUND 90
EACH DAY...WITH A SLIGHT CHANCE OF A LINGERING STORM OVERNIGHT.
WEDNESDAY THROUGH SATURDAY...
MODELS ARE IN GOOD AGREEMENT ON THE MEAN TROUGH PERSISTING OVER THE
EASTERN US THROUGH THE END OF THE WEEK...THOUGH WITH A FAIR AMOUNT
OF UNCERTAINTY REGARDING THE DETAILS OF NUMEROUS DISTURBANCES MOVING
FROM THE MIDWEST TO THE SOUTHEASTERN AND MID-ATLANTIC STATES. A
WEAK FRONTAL ZONE TO OUR NORTH IS PROJECTED TO SLIP SOUTH AND
POTENTIALLY MERGE WITH PIEDMONT TROUGH AS THE UPPER TROUGH BECOMES
SLIGHTLY MORE AMPLIFIED. NO SIGNIFICANT AIRMASS CHANGE IS EXPECTED
WITH THE FRONT...AND WHILE SCATTERED CONVECTION SHOULD BE PRIMARILY
DIURNAL EACH DAY...CYCLONIC FLOW ALOFT AND THE PRESENCE OF THE
BETTER LOW LEVEL CONVERGENCE MAY SUPPORT BETTER POTENTIAL FOR
CONVECTION CONTINUING OVERNIGHT. TEMPS WILL CONTINUE
TO NEAR NORMAL...UPPER 80S FOR HIGHS AND LOWER 70S FOR LOWS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 155 PM SATURDAY...
MOSTLY VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY PART OF THE 18Z
VALID TAF PERIOD...AS LINGERING MVFR CEILINGS CONTINUE TO RISE AND
SCATTER EARLY THIS SATURDAY AFTERNOON. IN VICINITY OF THE TRIAD...AND
ALONG THE INTERSTATE 85 CORRIDOR...THERE IS A BETTER CHANCE COMPARED
TO THE REST OF CENTRAL NORTH CAROLINA OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON INTO THIS EVENING. OVERNIGHT...THE PRIMARY AVIATION
ISSUE WILL BE THE DEVELOPMENT OF LOW CEILINGS. SOME FORECAST
GUIDANCE SUGGESTS THE PROBABILITY OF LOW CLOUDS EARLY SUNDAY TO BE
AT LEAST AS HIGH AS THIS SATURDAY MORNING...AND AS A RESULT
ANTICIPATE FAIRLY WIDESPREAD IFR CONDITIONS AROUND SUNRISE SUNDAY.
CEILINGS SHOULD GRADUALLY RISE INTO MVFR AND LIKELY VFR THROUGH THE
MORNING SUNDAY...BEGINNING AFTER 13Z TO 14Z.
BEYOND THE 18Z VALID TAF PERIOD...A MOIST AIR MASS CONTINUES OVER
CENTRAL NORTH CAROLINA. GIVEN LITTLE AIR MASS CHANGE...AVIATION
INTERESTS SHOULD PREPARE FOR AT LEAST SCATTERED...MAINLY AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY...WITH A FEW SHOWERS
AND STORMS POSSIBLY LINGERING THROUGH THE OVERNIGHT HOURS. LATE
NIGHT AND EARLY MORNING FOG WILL HAMPER VISIBILITIES ESPECIALLY
WHERE RAIN TENDS TO CONCENTRATE AND OVERNIGHT WINDS TURN LIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...CBL/DJF
SHORT TERM...BLS
LONG TERM...BLS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A SURFACE TROUGH OF LOW PRESSURE...IN A MOIST AIR MASS...WILL REMAIN
OVER THE REGION AT LEAST THROUGH THE MIDDLE OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS
MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING...
AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN
PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND
LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS
WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR
A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE
REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN
NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB
TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO
AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE
THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO
KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST
PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND
THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE
EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH
THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS
AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS
PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE
AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS
A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA...
TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE
WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY
NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR
SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN
THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE
HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES
COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A
STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND
SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED
INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS
AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB
THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND
WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN
THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 AM SATURDAY...
SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE
US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND
NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY
MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF
THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF
THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING
NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A
DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND
DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND
SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE
2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH
HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE
STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG
INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED
SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS
COULD RESULT IN LOCALIZED FLOODING.
HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...
MONDAY AND MONDAY NIGHT:
A BACKDOOR COLD FRONT IS EXPECTED TO STALL OVER VA ON MONDAY WITH
THE H85 TROUGH AXIS EXTENDING EAST THROUGH CENTRAL NC AND THE MAIN
UPPER LEVEL TROUGH OVER THE APPALACHIANS. THE ATMOSPHERE WILL BE
SUFFICIENTLY MOIST AND UNSTABLE TO ALLOW CONVECTION TO DEVELOP
DURING THE AFTERNOON AS WEAK UPPER LEVEL DISTURBANCES MOVE OVER THE
AREA. AHEAD OF THE MAIN TROUGH...THE 00Z GFS SHOWS A H3 SHORTWAVE
DISTURBANCE MOVING NORTHEAST FROM THE LOW OVER LOUISIANA AROUND THE
BASE OF THE TROUGH AND OVER NC MONDAY EVE/NIGHT. DEPENDING ON THE
TIMING...THIS FEATURE COULD ENHANCE CONVECTION LATE MONDAY...OR HELP
SUSTAIN CONVECTION INTO THE OVERNIGHT HOURS. GIVEN THE
UNCERTAINTY...WILL KEEP HIGHEST PRECIP CHANCES DURING THE AFT/EVE
HOURS AND ONLY INCREASE THEM SLIGHTLY DURING THE 03Z-07Z TIMEFRAME.
HIGHS MONDAY STILL EXPECTED TO BE IN THE MID TO UPPER 80S...WITH
OVERNIGHT LOWS MAINLY IN THE LOW TO MID 70S.
TUESDAY THROUGH FRIDAY:
THE UPPER LEVEL TROUGH AXIS SHOULD SHIFT EAST OVER CENTRAL NC ON
TUESDAY WHERE IT WILL LINGER THROUGH FRIDAY. AS THE H85 TROUGH
SLOWLY DRIFTS EAST ON TUESDAY...WINDS OVER THE WESTERN PORTIONS OF
THE AREA MAY SHIFT FROM SOUTHWEST TO MORE WESTERLY. THIS WOULD HELP
DRY OUT THE MID LEVELS A BIT LATE TUESDAY THROUGH WEDNESDAY...THUS
DECREASING PW VALUES SOME. MEANWHILE...THERE IS A DESCENT CHANCE THE
EAST WILL REMAIN UNDER SW FLOW...WITH BETTER MOISTURE ADVECTION AND
GREATER INSTABILITY. MID AND UPPER LEVEL DISTURBANCES MOVING OVER NC
DURING THIS PERIOD WILL LIKELY HELP GENERATE DIURNALLY DRIVEN
CONVECTION. ALTHOUGH GENERALLY CHANCES MAY BE SOMEWHAT BETTER IN THE
EAST...CONFIDENCE WITH REGARD TO LOCATION AND COVERAGE OF THE
CONVECTION REMAINS LOW AT THIS TIME...THUS WILL CARRY CHANCE POPS
DURING THE AFT/EVE ACROSS THE ENTIRE AREA THROUGH THE PERIOD. WILL
CONTINUE THE PERSISTENCE TEMP FORECAST...WITH HIGHS IN THE MID TO
UPPER 80S AND LOWS IN THE LOW TO MID 70S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 155 PM SATURDAY...
MOSTLY VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY PART OF THE 18Z
VALID TAF PERIOD...AS LINGERING MVFR CEILINGS CONTINUE TO RISE AND
SCATTER EARLY THIS SATURDAY AFTERNOON. IN VICINITY OF THE TRIAD...AND
ALONG THE INTERSTATE 85 CORRIDOR...THERE IS A BETTER CHANCE COMPARED
TO THE REST OF CENTRAL NORTH CAROLINA OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON INTO THIS EVENING. OVERNIGHT...THE PRIMARY AVIATION
ISSUE WILL BE THE DEVELOPMENT OF LOW CEILINGS. SOME FORECAST
GUIDANCE SUGGESTS THE PROBABILITY OF LOW CLOUDS EARLY SUNDAY TO BE
AT LEAST AS HIGH AS THIS SATURDAY MORNING...AND AS A RESULT
ANTICIPATE FAIRLY WIDESPREAD IFR CONDITIONS AROUND SUNRISE SUNDAY.
CEILINGS SHOULD GRADUALLY RISE INTO MVFR AND LIKELY VFR THROUGH THE
MORNING SUNDAY...BEGINNING AFTER 13Z TO 14Z.
BEYOND THE 18Z VALID TAF PERIOD...A MOIST AIR MASS CONTINUES OVER
CENTRAL NORTH CAROLINA. GIVEN LITTLE AIR MASS CHANGE...AVIATION
INTERESTS SHOULD PREPARE FOR AT LEAST SCATTERED...MAINLY AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY...WITH A FEW SHOWERS
AND STORMS POSSIBLY LINGERING THROUGH THE OVERNIGHT HOURS. LATE
NIGHT AND EARLY MORNING FOG WILL HAMPER VISIBILITIES ESPECIALLY
WHERE RAIN TENDS TO CONCENTRATE AND OVERNIGHT WINDS TURN LIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EDT SAT JUL 20 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH TODAY. AN
UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY OVER THE REGION SUNDAY
THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS
MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING...
AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN
PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND
LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS
WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR
A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE
REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN
NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB
TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO
AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE
THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO
KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST
PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND
THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE
EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH
THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS
AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS
PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE
AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS
A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA...
TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE
WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY
NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR
SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN
THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE
HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES
COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A
STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND
SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED
INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS
AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB
THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND
WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN
THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 AM SATURDAY...
SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE
US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND
NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY
MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF
THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF
THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING
NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A
DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND
DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND
SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE
2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH
HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE
STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG
INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED
SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS
COULD RESULT IN LOCALIZED FLOODING.
HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...
MONDAY AND MONDAY NIGHT:
A BACKDOOR COLD FRONT IS EXPECTED TO STALL OVER VA ON MONDAY WITH
THE H85 TROUGH AXIS EXTENDING EAST THROUGH CENTRAL NC AND THE MAIN
UPPER LEVEL TROUGH OVER THE APPALACHIANS. THE ATMOSPHERE WILL BE
SUFFICIENTLY MOIST AND UNSTABLE TO ALLOW CONVECTION TO DEVELOP
DURING THE AFTERNOON AS WEAK UPPER LEVEL DISTURBANCES MOVE OVER THE
AREA. AHEAD OF THE MAIN TROUGH...THE 00Z GFS SHOWS A H3 SHORTWAVE
DISTURBANCE MOVING NORTHEAST FROM THE LOW OVER LOUISIANA AROUND THE
BASE OF THE TROUGH AND OVER NC MONDAY EVE/NIGHT. DEPENDING ON THE
TIMING...THIS FEATURE COULD ENHANCE CONVECTION LATE MONDAY...OR HELP
SUSTAIN CONVECTION INTO THE OVERNIGHT HOURS. GIVEN THE
UNCERTAINTY...WILL KEEP HIGHEST PRECIP CHANCES DURING THE AFT/EVE
HOURS AND ONLY INCREASE THEM SLIGHTLY DURING THE 03Z-07Z TIMEFRAME.
HIGHS MONDAY STILL EXPECTED TO BE IN THE MID TO UPPER 80S...WITH
OVERNIGHT LOWS MAINLY IN THE LOW TO MID 70S.
TUESDAY THROUGH FRIDAY:
THE UPPER LEVEL TROUGH AXIS SHOULD SHIFT EAST OVER CENTRAL NC ON
TUESDAY WHERE IT WILL LINGER THROUGH FRIDAY. AS THE H85 TROUGH
SLOWLY DRIFTS EAST ON TUESDAY...WINDS OVER THE WESTERN PORTIONS OF
THE AREA MAY SHIFT FROM SOUTHWEST TO MORE WESTERLY. THIS WOULD HELP
DRY OUT THE MID LEVELS A BIT LATE TUESDAY THROUGH WEDNESDAY...THUS
DECREASING PW VALUES SOME. MEANWHILE...THERE IS A DESCENT CHANCE THE
EAST WILL REMAIN UNDER SW FLOW...WITH BETTER MOISTURE ADVECTION AND
GREATER INSTABILITY. MID AND UPPER LEVEL DISTURBANCES MOVING OVER NC
DURING THIS PERIOD WILL LIKELY HELP GENERATE DIURNALLY DRIVEN
CONVECTION. ALTHOUGH GENERALLY CHANCES MAY BE SOMEWHAT BETTER IN THE
EAST...CONFIDENCE WITH REGARD TO LOCATION AND COVERAGE OF THE
CONVECTION REMAINS LOW AT THIS TIME...THUS WILL CARRY CHANCE POPS
DURING THE AFT/EVE ACROSS THE ENTIRE AREA THROUGH THE PERIOD. WILL
CONTINUE THE PERSISTENCE TEMP FORECAST...WITH HIGHS IN THE MID TO
UPPER 80S AND LOWS IN THE LOW TO MID 70S.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1055 AM SATURDAY...
24-HR TAF PERIOD:
MVFR STRATUS WILL SLOWLY LIFT DURING THE REST OF THE MORNING.
ISOLATED-TO-SCATTERED SHOWERS AND THUNDERSTORMS SHOULD OCCUR THIS
AFTERNOON AND EVENING...WITH THE HIGHEST PROBABILITIES IN VICINITY
OF INTERSTATE 85.
LOOKING AHEAD:
AN UPPER LEVEL TROUGH WILL GRADUALLY AMPLIFY OVER THE REGION
SUNDAY THROUGH EARLY NEXT WEEK. THIS WILL RESULT IN AN ABOVE NORMAL
COVERAGE AND CHANCES FOR SHOWERS/THUNDERSTORMS DURING THE AFTERNOON
AND EVENING HOURS SUNDAY THROUGH WEDNESDAY. A POTENTIAL FOR SUB-VFR
FOG/STRATUS WILL ALSO PERSIST DURING THE EARLY MORNING HOURS...
PRIMARILY IN THE 06-11Z TIME FRAME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL/DJF
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...CBL/DJF
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
409 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A TYPICAL SUMMER PATTERN OF HIGH PRESSURE OFFSHORE AND A TROUGH
OF LOW PRESSURE INLAND WILL PERSIST THROUGH THE WEEKEND. A COLD
FRONT WILL MOVE INTO THE AREA BY WEDNESDAY OR THURSDAY OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
AS OF 355 AM SATURDAY...BAND OF SHOWERS MOVING UP THE COAST THIS
MORNING...WHICH WAS WELL DEPICTED BY THE HRRR AND A NUMBER OF
OTHER HIGH RESOLUTION MODELS. THIS ACTIVITY SHOULD LINGER NEAR OR
JUST OFFSHORE THROUGH THE EARLY MORNING HOURS BEFORE TRANSITIONING
INLAND AS SOME ADDITIONAL MID-LEVEL ENERGY MOVES NORTHEAST AROUND
THE PERIPHERY OF BROAD BERMUDA RIDGE TO THE EAST AND SURFACE
TROUGH OVER THE PIEDMONT SHARPENS DURING THE AFTERNOON. ADDITIONAL
SHOWERS/TSTMS WILL DEVELOP DURING THE MID TO LATE AFTERNOON HOURS
WITH THE FAVORED LOCATION BEING THE SOUTHERN COASTAL PLAINS AND
SOUTHERN COASTAL AREAS. IT WILL BE ANOTHER WARM AND HUMID DAY WITH
HIGHS IN THE UPPER 80S TO LOWER 90S IN MOST AREAS.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...NOT ALOT OF CHANGE TO THE FORECAST
TONIGHT. THE COMBINATION OF DEEP MOISTURE AND ADDITIONAL
SHORTWAVE ENERGY EMBEDDED IN SOUTHWEST FLOW WILL LEAD TO A LOW
CHANCE POPS THROUGH THE NIGHT TONIGHT. MINIMUM TEMPERATURES
TONIGHT SHOULD BE IN THE 73 TO 77 DEGREE RANGE.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 315 AM SAT...SW FLOW PERSISTS SAT NIGHT INTO SUN WITH
DEWPOINTS/PWATS RISING. SHORT TERM MODELS CONTINUE IN DECENT
AGREEMENT ON POTENTIAL FOR SHOWERS/TSTORMS RIDING UP THE COAST
EARLY SUN AS AREA OF CONVERGENCE EXISTS WITH WEAK SHORTWAVE
ENERGY MOVING NORTHEAST FROM OFF CHS/ILM TOWARDS THE CWA. WILL
MAINTAIN SLIGHT CHANCE POPS FOR COASTAL AREAS WITH CHANCE POPS
JUST OVER THE WATERS. PRECIP CHANCES INCREASE SUN AFTERNOON AS A
WEAK COOL FRONT APPROACHES AND SETTLES OVER EASTERN NC BEFORE
WASHING OUT LATER IN THE WEEK.
UPPER TROUGH OVER THE GREAT LAKES WILL DIG SOUTH MON/TUES AND
PERSIST OVER THE EASTERN CONUS THROUGH LATE WEEK...REINFORCING THE
RAIN CHANCES THROUGH THE PERIOD. WEAK PERTURBATIONS IN THE MID AND
UPPER LEVELS WILL ALSO AID CONVECTION DURING THE EXTENDED PERIOD.
PWATS INCREASE TO 2 INCHES OR GREATER SUN AND REMAIN HIGH THROUGH
MID TO LATE WEEK. HAVE CONTINUED THE TREND OF DIURNAL CONVECTION
EACH DAY WITH NEAR 50 PERCENT POPS INLAND DURING THE AFTERNOON
WITH 25-30 PERCENT POPS OVERNIGHT...WITH THIS PATTERN EXPECTED
THROUGH LATE WEEK. SEVERE WEATHER IS NOT EXPECTED AS SHEAR WILL BE
MINIMAL...THOUGH WITH ANY PULSE STORM AN ISOLATED STRONG TO SEVERE
WIND GUST IS POSSIBLE. WITH OVERALL WEAK STEERING FLOW...ANY
ORGANIZED CONVECTION WILL HAVE HEAVY RAINFALL POTENTIAL ESPECIALLY
IF CELLS TRAIN OVER THE SAME AREA. WILL HAVE TO WATCH OUT FOR
LOCALIZED FLOODING AS THIS UNSETTLED PATTERN LOOKS TO PERSIST.
TEMPS THROUGH THE LONG TERM PERIOD WILL BE CLOSER TO CLIMO...HIGHS
IN THE UPPER 80S TO NEAR 90 WITH LOW/MID 70S FOR OVERNIGHT LOWS.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 1245 AM SATURDAY...THERE APPEARS TO BE SUFFICIENT MIXING
OVERNIGHT TO PRECLUDE MUCH IN THE WAY OF FOG OR STRATUS AS WE KEEP
A LIGHT SOUTHWEST WIND OVERNIGHT. SLIGHTLY BETTER CHC OF TSTMS
INLAND SAT AFTN WITH CONTINUED INFLUX OF MSTR AND WEAK SHRT WV
ENERGY FROM S-SW. SW WINDS MAY GUST UP TO 20 KTS AS WELL DURING
AFTN.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 4 AM SAT...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH
THE PERIOD. AN UPPER TROUGH AND ASSOCIATED SFC FRONT APPROACH
FROM THE NW SUN BRINGING INCREASING CHANCES OF SCATTERED
SHOWERS/TSTORMS FOR THE TERMINALS THROUGH LATE WEEK. COULD SEE
BRIEF EARLY MORNING MVFR/IFR VSBYS DURING THE LONG TERM AS
FORECAST SOUNDINGS INDICATE GOOD BOUNDARY LAYER MOISTURE TRAPPED
UNDER A WEAK SURFACE BASED INVERSION. HOWEVER...BOUNDARY LAYER
MIXING MAY BE ENOUGH TO INHIBIT FOG FORMATION...THUS LOW
CONFIDENCE IN REDUCED AVIATION CONDITIONS EACH NIGHT.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 4 AM SATURDAY...HAVE ADDED THE CURRITUCK BEACH LIGHT TO
OREGON INLET LEG TO THE SMALL CRAFT ADVISORY AND HAVE MADE THE
EFFECTIVE TIME NOW AS LATEST OBSERVATIONS SHOWING WIND GUSTS AS
HIGH AS 25 KNOTS AT DUCK AND UP TO 29 KNOTS AT OREGON INLET. EVEN
SEEING WINDS AS HIGH AS 25 KNOTS IN THE PAMLICO SOUND. THE GUSTY
SW WINDS WILL CONTINUE TODAY BEFORE SUBSIDING A BIT TONIGHT. SEAS
WILL REMAIN AS HIGH AS 6 FEET PER LATEST WAVEWATCH BEFORE
SUBSIDING LATE TONIGHT OR EARLY SUNDAY MORNING.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL
TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE
LONG TERM. PRESSURE GRADIENT REMAINS TIGHT THROUGH EARLY SUNDAY
BEFORE WEAKENING DUE TO APPROACHING COOL FRONT DISSIPATING INLAND.
SCA CONDITIONS SHOULD DIMINISH ACROSS THE COASTAL WATERS BY SUN
AFTERNOON AS SEAS SUBSIDE BELOW 6 FEET. A BREAK IN THE GUSTY SW
WINDS MONDAY BEFORE REINFORCING TROUGH/FRONT APPROACH TUES INTO
MID WEEK. MARGINAL SCA CONDITIONS COULD DEVELOP ONCE AGAIN AS THE
GRADIENT INCREASES TUES NIGHT. NO SIGNIFICANT CHANGES TO THE
MEDIUM TERM...BUT HAVE ADJUSTED SEAS DOWN A FOOT FROM WED NIGHT
THROUGH THURS NIGHT...WHICH IS IN COLLABORATION WITH NEIGHBORING
OFFICES AND OPC.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON EDT SUNDAY FOR
AMZ152-154-156-158.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 PM EDT THIS EVENING
FOR AMZ135.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1250 AM EDT SAT JUL 20 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN EAST OF THE AREA WITH TROUGHING TO THE
WEST THROUGH THE WEEKEND AND INTO MIDWEEK. A FRONT WILL APPROACH
LATER IN THE WEEK BUT NOT MOVE THROUGH.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1240 AM SATURDAY...DECENT AGREEMENT AMONGST THE 4 KM EMC
WRF...HRR-R AND RAP MODELS SHOWING SOME WIDELY SCATTERED SHOWERS
AND TSTMS DEVELOPING ALONG THE SOUTHERN COAST AFTER 08Z. THE NAM
IS A BIT SLOWER IN THE DEVELOPMENT OF CONVECTION...BUT DOES SHOW T
THE PRECIPITATION AREA SPREADING NORTH AND WEST DURING THE
MORNING AS SOME MID-LEVEL ENERGY MOVES UP THE COAST AROUND THE
PERIPHERY OF LARGE BERMUDA HIGH. HAVE KEPT SLIGHT TO LOW CHC POPS
RIGHT ALONG THE IMMEDIATE COAST THROUGH 12Z. WHILE COVERAGE WILL
NOT BE PARTICULARLY GREAT...THERE IS SUFFICIENT INSTABILITY AND
MOISTURE TO HAVE SOME LOCALIZED DOWNPOURS...PARTICULAR THE
SOUTHERN COAST AND SOUTHERN COASTAL PLAINS. NO CHANGES TO
OVERNIGHT TEMP FORECAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
AS OF 400 PM FRI...DESPITE GENERAL AGREEMENT IN THE OVERALL
PATTERN THERE ARE SEVERAL DIFFERENCES IN THE MODELS REGARDING
TIMING AND LOCATION OF APPROACHING SHRTWV ENERGY AND
PRECIPITATION. SETTLED ON A COMPROMISE SOLUTION BETWEEN THE 12Z
GFS AND 12Z NAM SIMILAR TO THE 00Z ECMWF. EXPECT A CHANCE OF
PRECIPITATION TO DEVELOP ALONG THE SOUTHEAST COAST LATE TONIGHT
INTO TOMORROW MORNING...THEN SHIFTED THE FOCUS FOR ANY SHOWERS AND
TSTMS INLAND ALONG THE SEA BREEZE FOR SATURDAY AFTERNOON. MOS
GUIDANCE WAS IN CLOSE AGREEMENT AND FOLLOWED A BLEND THROUGH THE
PERIOD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
AS OF 330 PM FRI...SW FLOW INCREASES SAT NIGHT WITH DEWPOINTS/PWATS
ON THE RISE. MOST SHORT TERM MODELS IN AGREEMENT ON POTENTIAL FOR
SHOWERS/STORMS RIDING UP THE COAST SAT NIGHT AS AREA OF
CONVERGENCE EXISTS WITH WEAK SHORTWAVE ENERGY MOVING NORTHEAST.
HAVE MAINTAINED SLIGHT CHANCE POPS FOR COASTAL AREAS WITH CHANCE
POPS JUST OVER THE WATERS.
PRECIP CHANCES INCREASE SUN AS A WEAK COOL FRONT APPROACHES AND
SETTLES OVER EASTERN NC BEFORE WASHING OUT MIDWEEK. HOWEVER... IT
APPEARS THAT UNSETTLED WEATHER WILL EXIST MID WEEK AND BEYOND AS
LATEST TREND IN MODELS INDICATE PERSISTENT LONG WAVE TROUGHINESS
ACROSS THE EASTERN CONUS REINFORCING THE RAIN CHANCES. HAVE INC
POPS TO HIGH CHANCE MID WEEK DUE TO THESE LATEST TRENDS.
FOR SUNDAY...APPROACHING WEAK COOL FRONT ALONG WITH WEAK
PERTURBATIONS IN THE MID AND UPPER LEVELS WILL SPARK SCT MAINLY
AFTERNOON AND EARLY EVENING CONVECTION...WITH BEST CHANCES ACROSS
INLAND LOCALES. SEVERE WEATHER NOT EXPECTED AS SHEAR IS
MINIMAL...THOUGH WITH ANY PULSE STORM AN ISOLATED STRONG TO SEVERE
WIND GUST IS POSSIBLE. THE SAME HOLDS TRUE FOR THE REST OF THE
UPCOMING WEEK WITH ANY AFTERNOON CONVECTION. UPPER TROUGH OVER
THE GREAT LAKES WILL DIG SOUTH MON/TUES AND PERSIST OVER THE
EASTERN CONUS THROUGH LATE WEEK. PWATS INCREASE TO 2 INCHES OR
GREATER LATE THIS WEEKEND AND REMAIN HIGH THROUGH MID TO LATE WEEK.
WITH OVERALL WEAK STEERING FLOW...ANY ORGANIZED CONVECTION WILL
HAVE HEAVY RAINFALL POTENTIAL ESPECIALLY IF CELLS TRAIN OVER THE
SAME AREA. WILL HAVE TO WATCH OUT FOR LOCALIZED FLOODING AS THIS
UNSETTLED PATTERN LOOKS TO PERSIST. TEMPS THROUGH THE LONG TERM
PERIOD WILL BE CLOSER TO CLIMO...HIGHS IN THE UPPER 80S TO NEAR 90
WITH LOW/MID 70S FOR OVERNIGHT LOWS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 00Z SUNDAY/...
AS OF 1245 AM SATURDAY...THERE APPEARS TO BE SUFFICIENT MIXING
OVERNIGHT TO PRECLUDE MUCH IN THE WAY OF FOG OR STRATUS AS WE KEEP
A LIGHT SOUTHWEST WIND OVERNIGHT. SLIGHTLY BETTER CHC OF TSTMS
INLAND SAT AFTN WITH CONTINUED INFLUX OF MSTR AND WEAK SHRT WV
ENERGY FROM S-SW. SW WINDS MAY GUST UP TO 20 KTS AS WELL DURING
AFTN.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 PM FRI...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH
THE PERIOD. COULD SEE MVFR/IFR VSBYS DURING THE EARLY MORNING
HOURS AS FORECAST SOUNDINGS INDICATE GOOD MOISTURE TRAPPED UNDER
THE SURFACE BASED INVERSION WITH LIGHT WINDS...ESPECIALLY FOR AREAS
THAT RECEIVE RAINFALL DURING THE DAY. AN UPPER TROUGH AND ASSOCIATED
SFC FRONT APPROACH FROM THE NW SUN BRINGING INCREASING CHANCES OF
SCATTERED SHOWERS/TSTORMS FOR THE TERMINALS THROUGH MID TO LATE WEEK.
&&
.MARINE...
SHORT TERM /THROUGH SATURDAY/...
AS OF 1245 AM SATURDAY...MODERATE SW WINDS CONTINUE OVER THE
COASTAL WATERS WITH GUSTS INTO THE LOWER 20S IN MANY AREAS. SEAS
CONTINUE AT 1 TO 3 FEET NORTH AND UP TO 4 FEET SOUTHERN WATERS.
WILL MONITOR TRENDS TO SEE IF SCA NEED TO BE STARTED EARLIER.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 PM FRI...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL
TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE
LONG TERM. PRESSURE GRADIENT REMAINS TIGHT THROUGH EARLY SUNDAY
BEFORE WEAKENING DUE TO APPROACHING COOL FRONT WASHING OUT AND
DISSIPATING. SCA CONDITIONS SHOULD DIMINISH FOR PAMLICO SOUND SAT
NIGHT... WITH COASTAL WATERS SEEING IMPROVING CONDITIONS BY SUN
AFTERNOON AS SEAS SUBSIDE BELOW 6 FEET. A BREAK IN THE GUSTY SW
WINDS MONDAY BEFORE REINFORCING TROUGH/FRONT APPROACH TUE INTO MID
WEEK. MARGINAL SCA CONDITIONS COULD DEVELOP ONCE AGAIN AS THE
GRADIENT INCREASES.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON EDT SUNDAY FOR
AMZ152-154-156-158.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 PM EDT THIS EVENING
FOR AMZ135.
&&
$$
SYNOPSIS...CGG
NEAR TERM...CTC
SHORT TERM...CGG
LONG TERM...DAG/TL
AVIATION...CTC/DAG/TL
MARINE...CTC/DAG/TL/BM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
956 PM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 945 PM CDT SUN JUL 21 2013
DEEP CONVECTION WEAKENED EARLY THIS EVENING AS IT MOVED INTO THE
FAR WESTERN FORECAST AREA. T IS NOW VERY ISOLATED WITH STRONGEST
CELL JUST NORTH OF LAKOTA. LOW LEVEL JET FORECAST TO INCREASE WITH
BEST CONVERGENCE ALONG INTERNATIONAL BORDER AREA OF MN OVERNIGHT.
HAVE MAINTAIN HIGHEST POPS THIS AREA THROUGH MOST OF THE NIGHT.
ELSEWHERE STORM POTENTIAL MORE IN QUESTION AND HAVE OVERALL
DECREASED POPS SIGNIFICANTLY ACROSS SOUTH HALF OF FA WITH LACK OF
CONVERGENCE AND FAVORED MID LEVEL SUPPORT IN CANADA. ANY OTHER
CHANGES TO FORECAST MINOR.
UPDATE ISSUED AT 633 PM CDT SUN JUL 21 2013
LINE OF DEEP CONVECTION EXTENDING FROM NEAR PILOT MOUND MB TO
RUGBY AND WEST OF BIS. BASED ON CURRENT TIMING ADJUSTED POPS
DELAYING HIGHER POPS ACROSS NW AND KEEPING SOUTHERN FA DRY LONGER.
NO OTHER CHANGES THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 303 PM CDT SUN JUL 21 2013
MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR
TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR
PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT
SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY.
CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN
AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM
THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW
POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S.
EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM
MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM
COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT
WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO.
INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY
CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS
IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER
TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS
BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE
MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA
WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET
ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY
OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR
PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF
CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME
STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR
WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH
AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO
OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE
FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING
TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE
CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF
OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE
COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD
KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE
SEVERE POTENTIAL WILL GO.
LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY
MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY
WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL
BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN JUL 21 2013
SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY
OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED
ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS.
WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS
PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING
BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT
THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW
ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE
REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 633 PM CDT SUN JUL 21 2013
STORMS WILL TAKE A LITTLE LONGER GETTING INTO FA BASED ON CURRENT
CELL SPEED. MADE SOME MINOR ADJUSTMENTS TO TIMING HOWEVER KEPT VFR
CONDITIONS GOING ALTHOUGH COULD SEE SOME MVFR CONDITIONS UNDER
STRONGER STORMS. MAINTAINED DRY FORECAST FOR NOW AT FAR AND BJI.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...GODON
LONG TERM...GODON/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
638 PM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 633 PM CDT SUN JUL 21 2013
LINE OF DEEP CONVECTION EXTENDING FROM NEAR PILOT MOUND MB TO
RUGBY AND WEST OF BIS. BASED ON CURRENT TIMING ADJUSTED POPS
DELAYING HIGHER POPS ACROSS NW AND KEEPING SOUTHERN FA DRY LONGER.
NO OTHER CHANGES THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 303 PM CDT SUN JUL 21 2013
MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR
TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR
PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT
SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY.
CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN
AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM
THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW
POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S.
EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM
MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM
COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT
WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO.
INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY
CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS
IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER
TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS
BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE
MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA
WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET
ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY
OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR
PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF
CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME
STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR
WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH
AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO
OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE
FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING
TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE
CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF
OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE
COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD
KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE
SEVERE POTENTIAL WILL GO.
LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY
MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY
WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL
BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN JUL 21 2013
SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY
OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED
ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS.
WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS
PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING
BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT
THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW
ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE
REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 633 PM CDT SUN JUL 21 2013
STORMS WILL TAKE A LITTLE LONGER GETTING INTO FA BASED ON CURRENT
CELL SPEED. MADE SOME MINOR ADJUSTMENTS TO TIMING HOWEVER KEPT VFR
CONDITIONS GOING ALTHOUGH COULD SEE SOME MVFR CONDITIONS UNDER
STRONGER STORMS. MAINTAINED DRY FORECAST FOR NOW AT FAR AND BJI.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...GODON
LONG TERM...GODON/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
559 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 559 PM CDT SAT JUL 20 2013
REGIONAL RADAR IMAGERY SHOWS A COUPLE OF AREAS TO WATCH THIS
EVENING. FIRST IS IN OUR SOUTHWEST...WITH A SEVERE THUNDERSTORM
WATCH BOX UP TO OUR SOUTHWEST BORDER FROM SOUTH DAKOTA.
THUNDERSTORMS CONTINUE TO REMAIN SOUTH OF THE BORDER...BUT COULD
DEVELOP A BIT FURTHER NORTH WITH AN AGITATED CUMULUS FIELD EVIDENT
NEAR BAKER AND ALONG OUR FAR SOUTHWESTERN ZONES. THE OTHER AREA
WAS SEEN OVER NORTHEASTERN MONTANA WITH SEVERE THUNDERSTORMS
ROLLING OUT OF SOUTHERN SASKATCHEWAN AND INTO NORTHERN MONTANA.
WILL CONTINUE TO MONITOR DEVELOPMENT OF THESE THUNDERSTORMS FURTHER
EAST THIS EVENING AND OVERNIGHT...AS WHAT IS BEING INDICATED BY
THE HRRR (HIGH RESOLUTION RAPID REFRESH MODEL)...AS WELL AS THE
OTHER SHORT TERM MODELS.
WARM AIR ADVECTION INCREASES OVERNIGHT AS NAM/GFS SOUNDINGS SHOW
MODERATE VEERING WIND PROFILES FROM THE SFC TO 750MB. EXPECTING AN
INCREASE IN THE AREAL COVERAGE OF SHOWERS/ELEVATED THUNDERSTORMS
THROUGH EARLY SUNDAY MORNING...AS THEY CONTINUE TO DEVELOP ALONG A
WARM FRONT IN EASTERN MONTANA. NAM/GFS SOUNDINGS SHOW DECENT
INSTABILITY/CAPE ABOVE 750MB OVERNIGHT...WITH SHOWALTER INDICES
SHOWING AN INCREASED POTENTIAL FOR ELEVATED THUNDERSTORMS WEST OF
MINOT THROUGH 12Z SUNDAY. THUS WILL CONTINUE TO MENTION ISOLATED
TO SCATTERED THUNDERSTORMS WEST...AND JUST INTO PORTIONS OF
CENTRAL NORTH DAKOTA OVERNIGHT. WILL MONITOR FOR ANY SEVERE
POTENTIAL DURING THE EVENING/OVERNIGHT. MOST OF WESTERN AND
CENTRAL NORTH DAKOTA GET INTO THE WARM SECTOR BY LATE MORNING AND
EARLY AFTERNOON SUNDAY...SETTING THE STAGE FOR SEVERE THUNDERSTORMS
ALONG AND AHEAD OF AN ADVANCING COLD FRONT. SEE PREVIOUS DISCUSSION
BELOW FOR MORE DETAILS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 310 PM CDT SAT JUL 20 2013
MAIN CONCERNS THIS PERIOD WILL BE THUNDERSTORMS ASSOCIATED WITH A
WARM FRONT EXTENDED ACROSS EASTERN MONTANA THAT IS FORECAST TO
TRACK EAST ACROSS THE STATE LATE TONIGHT AND SUNDAY. SATELLITE
LOOPS SHOW CLOUD COVER ACROSS WESTERN NORTH DAKOTA IN LOW LEVEL
MOIST UP SLOPE FLOW. A BAND OF MID LEVEL SHOWERS AND ISOLATED
THUNDERSTORMS IS MOVING THROUGH SOUTH CENTRAL NORTH DAKOTA. THIS IS
EXPECTED TO DIMINISH AS IT MOVES EAST.
THE FOCUS FOR TONIGHT AND SUNDAY WILL BE THE WARM FRONT IN
EASTERN MONTANA THIS WILL BE PROVIDE LIFT AND WITH A SHORT WAVE
TROUGH SUPPORT THUNDERSTORMS ACROSS THE NORTHWEST...AND THEN THE
NORTH CENTRAL ON SUNDAY. ADDED THE MENTION OF SEVERE WHERE SPC HAS
DEFINED THE SLIGHT RISK SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 PM CDT SAT JUL 20 2013
THE RISK OF SEVERE WEATHER CONTINUES FROM SUNDAY AFTERNOON INTO
THE NIGHT...MAINLY OVER THE CENTRAL AND EASTERN PARTS OF THE
FORECAST AREA.
LONG TERM MODELS ARE IN AGREEMENT THROUGH THE PERIOD ON THE BIG
PICTURE...NAMELY THAT THE H5 RIDGE OFF THE SOUTHWEST COAST BUILDS
EAST INTO THE DESERT SOUTHWEST AND EXPENDS NORTH INTO THE NORTHERN
ROCKIES AND AMPLIFIES. THIS KEEPS A WEAK NORTHWEST FLOW OVER NORTH
DAKOTA WITH CHANCES FOR THUNDERSTORMS COMING AS RIDGE RIDER SHORT
WAVES CREST THE RIDGE AND PASS THROUGH EVERY OTHER DAY. THIS
PATTERN IS ENHANCED AS AN H5 LOW CUTS OFF OVER ONTARIO AND SENDS A
TROUGH AXIS THROUGH DURING THE THURSDAY-FRIDAY TIME FRAME.
THAT...AS INDICATED IN THE PREVIOUS LONG TERM DISCUSSION...WILL BE
THE GREATEST CHANCES FOR STORMS IN THE LONG TERM...AFTER SUNDAY
NIGHT. BUT AGAIN...THERE ARE CHANCES ABOUT EVERY DAY AS TIMING OF
THE WAVES WILL LIKELY CHANGE FROM FORECAST TO FORECAST.
TEMPERATURES SHOULD BE FAIRLY STEADY IN THE PATTERN...AND NOT TOO
FAR FROM NORMAL...GENERALLY IN THE MID 70S NORTHEAST TO MID 80S
SOUTHWEST AND LOWS IN THE 50S TO LOWER 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 559 PM CDT SAT JUL 20 2013
LATEST SATELLITE AND RADAR IMAGERY SHOWS SCT/BKN VFR CIGS WITH DRY
CONDITIONS AT THE AERODROMES. AN AREA OF SHOWERS AND THUNDERSTORMS
IN NORTHEASTERN MONTANA WILL BEGIN TO SHIFT EAST OVERNIGHT...PRODUCING
A MENTION FOR PREDOMINANT SHOWERS AND A VCTS AT KMOT/KBIS BY 09Z
SUNDAY. ALTHOUGH VFR CIGS/VSBYS ARE ANTICIPATED NEXT 24HR...ANY OF
THE STRONGER SHOWERS OR THUNDERSTORMS MAY RESULT IN BRIEF PERIODS
OF MVFR/LOW VFR CIGS/VSBYS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...WAA
LONG TERM...JPM
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
110 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 109 AM CDT SAT JUL 20 2013
OVERALL THE INHERITED FORECAST IS ON TRACK AND BLENDED TO THE
06 UTC OBSERVATIONS...WITH THE 04 UTC HRRR WEIGHTED HEAVILY FOR
POPS FOR THE REMAINDER OF THE NIGHT GIVEN ITS GOOD HANDLING OF
CONVECTIVE COVERAGE AND EVOLUTION THE PAST FEW HOURS.
UPDATE ISSUED AT 903 PM CDT FRI JUL 19 2013
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED THUNDERSTORMS
STRETCHED FROM NORTHWEST TO SOUTHEAST ALONG AND AHEAD OF A COLD
FRONT. BASED ON THE 3HR PRESSURE CHANGE...THIS FRONT WOULD ROUGHLY
FOLLOW ALONG A WATFORD CITY TO HAZEN...AND INTO STEELE AND
EDGELEY. SEVERAL OUTFLOWS EVIDENT WHICH MAY PRODUCE MORE
CONVECTION ACROSS SOUTH CENTRAL NORTH DAKOTA THROUGH THE EVENING
AND OVERNIGHT...WHICH IS WHAT THE HRRR INDICATES AS WELL. SEVERE
THREAT LOOKS TO REMAIN ISOLATED BUT WILL NEED TO CLOSELY MONITOR.
UPDATE ISSUED AT 659 PM CDT FRI JUL 19 2013
LATEST 3HR PRESSURE CHANGE SHOWS A COLD FRONT NEAR/ALONG OUR
NORTHERN BORDER SLOWLY PUSHING SOUTH. SCATTERED THUNDERSTORMS
CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT AS THEY MOVE
SOUTHEAST WITH TIME. LATEST HRRR/HIGH RESOLUTION RAPID REFRESH MODEL
SHOWS FIRST AREA OF SHOWERS AND THUNDERSTORMS IN NORTH CENTRAL
NORTH DAKOTA MOVING INTO THE JAMES RIVER VALLEY THROUGH 05Z
SATURDAY. THE OTHER ITEM OF INTEREST ARE THE SHOWERS AND
THUNDERSTORMS IN NORTHEAST MONTANA WHICH ARE FORECAST TO REACH
KBIS BY AROUND 07Z. EXPECTING ISOLATED SEVERE THUNDERSTORMS TO
CONTINUE THROUGH THE EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 306 PM CDT FRI JUL 19 2013
SHORT TERM CONCERNS INVOLVE THUNDERSTORMS NORTH CENTRAL ASSOCIATED
WITH A CANADIAN COLD FRONT SLIDING SOUTH ACROSS THE REGION. CAPE
VALUES SHOW POTENTIAL FOR STRONG THUNDERSTORMS BUT MID LEVEL LAPSE
RATES AROUND 5 TO 6 DEGREES SHOULD LIMIT THE SEVERE POTENTIAL.
HOWEVER THE POTENTIAL FOR SOME HAIL AND GUSTY WINDS EXISTS THIS
EVENING. EXPECT SOME DIURNAL MINIMUM TONIGHT FOR THE STORMS...AND
SCATTERED THUNDERSTORMS ALONG THE FRONTAL ZONE SOUTH CENTRAL AND
WEST SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 PM CDT FRI JUL 19 2013
H5 PATTERN PER GFS/ECMWF CONTINUES WITH MOSTLY A NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. PERIODIC UPPER DISTURBANCES IN COMBINATION
WITH INSTABILITY AND DYNAMICAL PARAMETERS IN PLACE WILL ALLOW FOR A
CHANCE OF SHOWERS AND/OR THUNDERSTORMS ALMOST EVERYDAY...WITH THE
EXCEPTION OF MONDAY...WHERE A DRY DAY IS FORECAST.
FOR SATURDAY NIGHT AND SUNDAY...MAIN HIGHLIGHT HERE IS A MORE
SIGNIFICANT SHORTWAVE MOVING THROUGH SOUTHERN SASKATCHEWAN SUNDAY
MORNING AND INTO SOUTHERN MANITOBA BY SUNDAY AFTERNOON. A SURFACE
COLD FRONT WILL BE ASSOCIATED WITH THE SHORTWAVE ALOFT AS IT SLIDES
FROM WEST TO EAST SUNDAY AFTERNOON AND EVENING. BEST FORCING/OMEGA
RESIDES IN THE NORTH CENTRAL SUNDAY AFTERNOON THEN SHIFTS INTO EAST
CENTRAL NORTH DAKOTA SUNDAY EVENING. VERTICAL MOTION IS ENHANCED BY
THE LEFT EXIT REGION OF A 60KT H3 JET STREAK ACROSS THE
AFOREMENTIONED AREA. GFS SHOWS ENOUGH CAPE AND 0-6KM SHEAR OF 45KT
TO 50KT FOR ORGANIZED STORMS WHICH WILL FAVOR SOME SEVERE
THUNDERSTORMS NORTH CENTRAL THROUGH EAST CENTRAL SUNDAY AFTERNOON
THROUGH SUNDAY EVENING. SPC DAY 3 OUTLOOK HAS THE ABOVE AREA IN A
SEE TEXT WITH HAIL AND WIND AS THE PRIMARY THREATS. H85 TEMPS RISE
TO BETWEEN +26C TO +28C IN THE WARM SECTOR SUNDAY AFTERNOON WEST PER
NAM/GFS...HIGHS WILL TOP OUT AROUND 90 OR LOWER 90S. HAVE INCREASED
TEMPS TO REFLECT THIS...HOWEVER DID NOT GO AS WARM AS THE NAM MOS
WANTED DUE TO SOME CLOUD COVER HOLDING TEMPS BACK IN THE MORNING TO
EARLY AFTERNOON. SHOULD BE A QUICK RISE THEREAFTER.
MONDAY...BEHIND THE COLD FRONT...GFS SOUNDINGS SHOW LOW LEVEL COLD
AIR ADVECTION WITH NEUTRAL ADVECTION ALOFT WILL YIELD A COOLER/DRIER
DAY WITH HIGHS IN THE UPPER 70S NORTH TO UPPER 80S SOUTH.
FOR TUESDAY THROUGH FRIDAY...ADDITIONAL SHORTWAVES EMBEDDED IN THE
NORTHWEST FLOW WILL INTERACT WITH THE AFTERNOON/EVENING INSTABILITY
AND SOME JET FORCING AT TIMES TO INITIATE A CHANCE OF
SHOWERS/THUNDERSTORMS.
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 109 AM CDT SAT JUL 20 2013
OUTSIDE OF THUNDERSTORMS TONIGHT...VFR CONDITIONS ARE FORECAST FOR
THE 06 UTC TAF CYCLE. ISOLATED TO SCATTERED THUNDERSTORMS ARE
POSSIBLE AT KISN...KDIK...KMOT AND KBIS THROUGH THE OVERNIGHT AND
CODED AS VCTS FOR NOW AND WILL AMEND BASED ON RADAR TRENDS.
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...KS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
433 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A WEAK SHORTWAVE ALOFT WILL COMBINE WITH DIURNAL HEATING AND
ABUNDANT MOISTURE FOR AFTERNOON AND EVENING CONVECTION. A COLD
FRONT WILL PUSH SOUTHEAST INTO SOUTHERN WEST VIRGINIA SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CODED CATEGORICAL POPS WITH THE INCOMING H5 VORTICITY MAXIMUM
ASSOCIATED WITH BROAD LOW PRESSURE SYSTEM WAY NORTH IN CANADA.
LOBES OF VORTICITY AT H5 WILL RIDE AROUND THE PERIPHERY TODAY
PROVIDING SOME DYNAMIC LIFT. PWATS WILL INCREASE FROM 1.5 TO 2
INCHES BY THIS EVENING ACROSS THE LOWLANDS. THIS SHORTWAVE SEEMS
TO DIMINISH IN INTENSITY OR SLOWS DOWN ACROSS NORTHERN HALF OF WV.
THIS SCENARIO COULD PRODUCE HEAVY DOWNPOURS CAPABLE TO PRODUCE
FLASH FLOODING. THEREFORE...ISSUED A FLASH FLOOD WATCH FOR THE
NORTHERN HALF OF THE AREA THROUGH SUNDAY AFTERNOON.
THE FOCUS OF THE CONVECTION IS EXPECTED EARLY TONIGHT ACROSS
CENTRAL WV...THEN SLOWLY MOVE SOUTH AND EAST TO AFFECT THE
SOUTHERN PORTIONS. THERE ARE SOME UNCERTAINTY WHERE THE BOUNDARY
WILL STALL ATTM.
THERE IS A SLIGHT RISK OF SEVERE WEATHER AT BOTH SIDES OF THE OH
RIVER...INCLUDING NORTH CENTRAL WEST VIRGINIA.
WENT WITH TEMPERATURES CLOSER TO THE BIAS CORRECTED MET GUIDANCE
THROUGH THE PERIOD.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
MODELS AGREE THE FRONT WILL BE STALLED ACROSS THE CENTRAL OR
NORTHERN PORTIONS OF THE AREA SUNDAY...THEN SLOWLY LIFT BACK NORTH
SUNDAY NIGHT INTO MONDAY...AND FINALLY BE WELL NORTH OF THE AREA BY
MONDAY NIGHT. OUR AREA WILL ALSO BE ON THE SOUTHERN EDGE OF THE
WESTERLIES ALOFT. EMBEDDED SHORT WAVES MOVING OVER THE WARM AND
SOUPY AIRMASS WILL CONTINUE A HIGH THREAT FOR SHOWERS AND
THUNDERSTORMS RIGHT THROUGH TUESDAY. IN THIS PATTERN...TRACKING AND
TIMING OF THESE SHORT WAVES WILL BE DIFFICULT TO EXACTLY DETERMINE
THE CONVECTION SCENARIO. SO...WILL CONCENTRATE CONVECTION SUNDAY AND
SUNDAY NIGHT IN THE CENTRAL AND SOUTH JUST AHEAD OF THE
FRONT...SHIFTING INTO NORTHERN AREAS MONDAY AS THE FRONT LIFTS BACK
NORTH. ON TUESDAY...WILL COAT A HIGH CHANCE EVERYWHERE...EVEN WITH
THE FRONT NORTH OF THE AREA...AS THE MODELS DEPICT A FAIRLY STRONG
AND MORE SYNOPTIC SCALE SHORT WAVE IN THE FLOW. EXCEPT FOR POSSIBLY
THE NORTHERN AREAS SEEING A BRIEF DECREASE IN THE HEAT AND HUMIDITY
SUNDAY...WE LOOK FOR THE WARMTH AND MUGGIES TO DOMINATE RIGHT
THROUGH TUESDAY.
SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE
UNSETTLED WEATHER CONTINUES.
NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND
LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN.
TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE
MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE.
HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM
WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR
FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF
2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS.
ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT
AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER
PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER.
BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION
AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER
WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A
LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES.
OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS
ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION
WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK
SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER
OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT
H5.
ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES
THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR
AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION
SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND
AFFECT MOST SITES AT THE END OF THE PERIODS..
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT.
SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY.
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 SAT 07/20/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY L L L L L H H H H H H H
HTS CONSISTENCY L L L L L L 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 H H H H H H
PKB CONSISTENCY L L L L L L H H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS
EACH MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SUNDAY
AFTERNOON FOR WVZ007>011-014>020-027>032-037>040-046-047.
OH...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SUNDAY
AFTERNOON FOR OHZ066-067-075-076-083>086.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/JMV/MZ
NEAR TERM...ARJ
SHORT TERM...JMV
LONG TERM...KTB
AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
313 AM EDT SAT JUL 20 2013
.SYNOPSIS...
UPPER HIGH PRESSURE DISSIPATING AS UPPER TROUGH APPROACHES GREAT
LAKES. A COLD FRONT SAGS SLOWLY SOUTHWARD INTO THE AREA THIS
WEEKEND...AND LIFTS BACK NORTH AS A WARM FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED SKIES...POPS...AND WEATHER THROUGH SATURDAY PER LATEST
MODEL RUNS...RADAR...AND SATELLITE IMAGES. REST OF FORECAST
REMAINS REPRESENTATIVE.
PREVIOUS DISCUSSION BELOW...
STRATIFORM RAIN LEFT FROM THE CONVECTION TONIGHT. SHOULD DISSOLVE
OUT OVER THE NEXT COUPLE OF HOURS.
FOCUS THEN TURNS TO THE CONVECTION LATER TONIGHT. LOCAL MODELS
BRING THE RENEWED ACTIVITY LATE TONIGHT INTO THE SOUTHEAST OHIO
COUNTIES BY 12Z. THIS IS AHEAD OF THE LINE OF CONVECTION CURRENTLY
WORKING THROUGH THE SOUTHERN GREAT LAKES AREA...ALTHOUGH IT COULD
ALSO DEVELOP FROM THE VORT MAX TO THE WEST OVER SOUTHERN INDIANA.
DIFFICULT TO TELL AT THIS TIME WHAT THE EXACT SOURCE WILL BE.
PREVIOUS DISCUSSION...
SCATTERED CONVECTION ONGOING ACROSS ENTIRE CWA. APPEARS TO BE JUST
AHEAD OF VORT MAX IN EASTERN KY PER WATER VAPOR IMAGERY. EXPECT
VORT MAX TO MOVE ACROSS LATE THIS AFTERNOON AND EVENING...AND
SHOULD SEE DECREASING CONVECTION AS WE HEAD AFTER SUNSET WITH
LOSS OF HEATING AND VORT MAX MOVING OUT TO THE NORTHEAST.
ELONGATED LINEAR VORT MAX...WELL AHEAD OF THE COLD FRONT...WILL
MOVE INTO FORECAST AREA FROM NW TOMORROW. ENTERING NW CWA 12Z-15Z
AND THEN RUNNING FROM ABOUT HTS-EKN BY END OF NEAR TERM AT 00Z
SUN. TIED LIKELY POPS TO THIS TIME/AREA TREND AS WELL. ALSO
INCLUDED HEAVY RAIN MENTION WITH LIKELY POPS. THINK WE WILL BE ON
THE SOUTHERN FRINGE OF ANY ORGANIZED SEVERE THREAT. BEST CHANCE
FOR ANY ORGANIZED SEVERE WEATHER WOULD BE A COMPLEX THAT FORMS
ALONG THE FRONT TO OUR NW AND THEN ARRIVES INTO OUR SE OHIO
COUNTIES IN THE EVENING WITH DAMAGING WINDS THE MOST LIKELY THREAT.
HOWEVER AS HEIGHTS AND FREEZING LEVELS DROP A BIT...LOCAL
DOWNPOURS...GUSTY WINDS AND SMALL HAIL POSSIBLE IN ANY STRONGER
CELLS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
MODELS AGREE THE FRONT WILL BE STALLED ACROSS THE CENTRAL OR
NORTHERN PORTIONS OF THE AREA SUNDAY...THEN SLOWLY LIFT BACK NORTH
SUNDAY NIGHT INTO MONDAY...AND FINALLY BE WELL NORTH OF THE AREA BY
MONDAY NIGHT. OUR AREA WILL ALSO BE ON THE SOUTHERN EDGE OF THE
WESTERLIES ALOFT. EMBEDDED SHORT WAVES MOVING OVER THE WARM AND
SOUPY AIRMASS WILL CONTINUE A HIGH THREAT FOR SHOWERS AND
THUNDERSTORMS RIGHT THROUGH TUESDAY. IN THIS PATTERN...TRACKING AND
TIMING OF THESE SHORT WAVES WILL BE DIFFICULT TO EXACTLY DETERMINE
THE CONVECTION SCENARIO. SO...WILL CONCENTRATE CONVECTION SUNDAY AND
SUNDAY NIGHT IN THE CENTRAL AND SOUTH JUST AHEAD OF THE
FRONT...SHIFTING INTO NORTHERN AREAS MONDAY AS THE FRONT LIFTS BACK
NORTH. ON TUESDAY...WILL COAT A HIGH CHANCE EVERYWHERE...EVEN WITH
THE FRONT NORTH OF THE AREA...AS THE MODELS DEPICT A FAIRLY STRONG
AND MORE SYNOPTIC SCALE SHORT WAVE IN THE FLOW. EXCEPT FOR POSSIBLY
THE NORTHERN AREAS SEEING A BRIEF DECREASE IN THE HEAT AND HUMIDITY
SUNDAY...WE LOOK FOR THE WARMTH AND MUGGIES TO DOMINATE RIGHT
THROUGH TUESDAY.
SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE
UNSETTLED WEATHER CONTINUES.
NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND
LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN.
TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE
MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE.
HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM
WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR
FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF
2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS.
ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT
AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER
PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER.
BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION
AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER
WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A
LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES.
OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS
ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION
WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK
SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER
OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT
H5.
ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES
THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR
AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION
SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND
AFFECT MOST SITES AT THE END OF THE PERIODS..
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT.
SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY.
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 SAT 07/20/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY L L L L L H H H H H H H
HTS CONSISTENCY L L L L L L 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 H H H H H H
PKB CONSISTENCY L L L L L L H H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS
EACH MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/JMV/MZ
NEAR TERM...MZ/26
SHORT TERM...JMV
LONG TERM...KTB
AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
158 AM EDT SAT JUL 20 2013
.SYNOPSIS...
UPPER HIGH PRESSURE DISSIPATING AS UPPER TROUGH APPROACHES GREAT
LAKES. A COLD FRONT SAGS SLOWLY SOUTHWARD INTO THE AREA THIS
WEEKEND...AND LIFTS BACK NORTH AS A WARM FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATED SKIES...POPS...AND WEATHER THROUGH SATURDAY PER LATEST
MODEL RUNS...RADAR...AND SATELLITE IMAGES. REST OF FORECAST
REMAINS REPRESENTATIVE.
PREVIOUS DISCUSSION BELOW...
STRATIFORM RAIN LEFT FROM THE CONVECTION TONIGHT. SHOULD DISSOLVE
OUT OVER THE NEXT COUPLE OF HOURS.
FOCUS THEN TURNS TO THE CONVECTION LATER TONIGHT. LOCAL MODELS
BRING THE RENEWED ACTIVITY LATE TONIGHT INTO THE SOUTHEAST OHIO
COUNTIES BY 12Z. THIS IS AHEAD OF THE LINE OF CONVECTION CURRENTLY
WORKING THROUGH THE SOUTHERN GREAT LAKES AREA...ALTHOUGH IT COULD
ALSO DEVELOP FROM THE VORT MAX TO THE WEST OVER SOUTHERN INDIANA.
DIFFICULT TO TELL AT THIS TIME WHAT THE EXACT SOURCE WILL BE.
PREVIOUS DISCUSSION...
SCATTERED CONVECTION ONGOING ACROSS ENTIRE CWA. APPEARS TO BE JUST
AHEAD OF VORT MAX IN EASTERN KY PER WATER VAPOR IMAGERY. EXPECT
VORT MAX TO MOVE ACROSS LATE THIS AFTERNOON AND EVENING...AND
SHOULD SEE DECREASING CONVECTION AS WE HEAD AFTER SUNSET WITH
LOSS OF HEATING AND VORT MAX MOVING OUT TO THE NORTHEAST.
ELONGATED LINEAR VORT MAX...WELL AHEAD OF THE COLD FRONT...WILL
MOVE INTO FORECAST AREA FROM NW TOMORROW. ENTERING NW CWA 12Z-15Z
AND THEN RUNNING FROM ABOUT HTS-EKN BY END OF NEAR TERM AT 00Z
SUN. TIED LIKELY POPS TO THIS TIME/AREA TREND AS WELL. ALSO
INCLUDED HEAVY RAIN MENTION WITH LIKELY POPS. THINK WE WILL BE ON
THE SOUTHERN FRINGE OF ANY ORGANIZED SEVERE THREAT. BEST CHANCE
FOR ANY ORGANIZED SEVERE WEATHER WOULD BE A COMPLEX THAT FORMS
ALONG THE FRONT TO OUR NW AND THEN ARRIVES INTO OUR SE OHIO
COUNTIES IN THE EVENING WITH DAMAGING WINDS THE MOST LIKELY THREAT.
HOWEVER AS HEIGHTS AND FREEZING LEVELS DROP A BIT...LOCAL
DOWNPOURS...GUSTY WINDS AND SMALL HAIL POSSIBLE IN ANY STRONGER
CELLS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
BASING FORECAST ON SURFACE FRONT REACHING NEAR A MGW-PKB-UNI LINE BY
12Z SUNDAY...THEN STALLING OUT DURING THE DAY ON SUNDAY...BETWEEN
THAT LINE AND THE HTS-CRW-EKN LINE.
STILL SOME QUESTION HOW QUICKLY THE PRE FRONTAL CONVECTION SAGS
SOUTH INTO NORTHEAST KENTUCKY TO SOUTHERN WEST VIRGINIA SATURDAY
EVENING. TRIED TO SLOW THE SOUTHERN PROGRESS OF THE HIGHER POPS
SOUTHWARD.
PLENTY OF LOW CLOUDS SHOULD LINGER NORTH OF THE FRONT SUNDAY
MORNING. THAT IN COMBINATION WITH THE HIGHER PROBABILITIES OF RAIN
ACROSS THE SOUTHERN HALF OF THE CWA...KEPT MAXIMUM TEMPERATURES
LOWER THAN MOS GUIDANCE.
NEXT MID LEVEL DISTURBANCE MOVES UP THE OHIO VALLEY OVERNIGHT SUNDAY
NIGHT...SO HAVE POPS INCREASING AND MOVING BACK NORTHEAST. THE AXIS
OF THAT MID LEVEL TROF AT 700 TO 500 MB PASSES OVERNIGHT MONDAY
NIGHT.
SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE
UNSETTLED WEATHER CONTINUES.
NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND
LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN.
TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE
MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE.
HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM
WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR
FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF
2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS.
ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT
AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER
PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER.
BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION
AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER
WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A
LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES.
OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS
ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION
WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK
SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER
OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT
H5.
ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES
THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR
AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION
SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND
AFFECT MOST SITES AT THE END OF THE PERIODS..
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT.
SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY.
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 SAT 07/20/13
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 M L L L L L L M H H H H
HTS CONSISTENCY L L L L L L L L 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 M L L L L L L L H H H H
CKB CONSISTENCY M M M M M M M M H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS
EACH MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/MZ
NEAR TERM...MZ/26
SHORT TERM...KTB
LONG TERM...KTB
AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
915 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A HEAT WAVE-ENDING COLD FRONT MOVES THOUGH LATE TODAY...
A MID-TROPOSPHERIC TROUGH WILL PUSH COOLER DRIER AIR INTO THE
REGION OVER THE NEXT 24 HOURS. IT WILL ALSO TRIGGER SOME STRONG
THUNDERSTORMS. A SECOND TROUGH AND ATTENDANT COLD FRONT COULD
TRIGGER SHOWERS TOWARD MID-WEEK. OVERALL...AN UPPER LEVEL TROUGH
WILL DOMINATE OUR AREA. THUS MOST OF NEXT WEEK WILL FEEL
RELATIVELY COOL TO OUR RECENT HEAT WAVE.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
13Z...EARLIER WIDESPREAD RAIN SHIELD TO THE NORTH HAS DISSIPATED.
ONLY REMAINING SHOWERS ARE IN THE SW/SC MTS...BUT TAME AT THIS
TIME. RUC HANDLING THE CURRENT COVERAGE OF THE SHOWERS WELL...AND
OUTPUT HAS BEEN USED AS BASIS FOR REST OF THE POP GRIDS FOR TODAY.
SEVERE STORMS STILL POSSIBLE...BUT WE WILL HAVE TO GET RID OF THE
HIGHER CLOUDS. THIS SHOULD NOT BE A PROBLEM...AND BLYR MOISTURE IS
GOING TO BE HIGH. DEWPOINTS ACTUALLY REMAIN HIGHER IN THE AREAS
WHICH WERE DRY OVERNIGHT.
REST AS FOLLOWS FROM PREV DISCS...
0820Z UPDATE...THE SERIES OF CONVECTIVE LINES
AND THE MCS ACTIVITY TO OUR WEST TRIGGERED SOME SHOWERS IN WARREN
COUNTY. THE LATEST ROUND OF INTENSE CONVECTION IS NOW IN NORTHERN
OHIO. MOST HIGH RESOLUTION MODELS HAVE DIFFICULTY BRINGING THIS
CONVECTION INTO OUR REGION WITH MUCH VIGOR. SHOWERS AND
THUNDERSTORMS ARE LIKELY IN NORTHWESTERN AREAS THIS MORNING.
THESE SEEM HIGH RESOLUTION MODELS IMPLY A BETTER CHANCE OF STRONG
STORMS IN BOTH SOUTHWEST AND CENTRAL AREAS...GENERALLY AFTER ABOUT
2 PM TODAY. THE NCEP MODEL SUITE AND ENSEMBLES IMPLY A STRONG LOW-
LEVEL JET...SOME GOOD CAPE OVER 1500JKG-1 AND STRONG SOUTHWESTERLY
FLOW. THUS SOME MULTI-CELLULAR LINES COULD DEVELOP AND THIS WOULD
LIKELY PRODUCE SOME POTENTIAL SEVERE STORMS LATER THIS AFTERNOON.
MORE MODESTLY...OVERNIGHT TEMPERATURES ARE IN THE 70S NEARLY
EVERYWHERE...EVEN IN THE NORTHWEST DUE TO CLOUDS AND ENHANCED
SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT TO OUR NORTHWEST. DEW
POINTS ARE IN THE 60S TO NEAR 70 IN THE EXTREME SOUTHEAST. THE
TEMPERATURE AND HUMIDITY VALUES KEEP ALL PUT A FEW ISOLATED POINT
APPARENT TEMPS BELOW 100...NO HEAT PRODUCTS TODAY.
IT WILL STILL BE HOT IN EAST AS THE COLD FRONT WILL BE SLOWER TO
ARRIVE. BEST CHANCE PRECIPITATION WILL BE BEFORE 19Z IN NORTHWEST
AND AFTER ABOUT 20Z IN SOUTHERN AREAS.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE COOLER AND DRIER AIR SHOULD TAKE HOLD OF THE NORTHERN TIER BY
EARLY EVENING AND THE CHANCE OF PRECIPITATION WILL BE LOW. MOST
CENTRAL AREAS TOO SHOULD BE NORTH OF THE MAIN AREA OF RAIN THREAT
WITHIN A FEW HOURS OF 6 PM. THE SREF AND OTHER MODELS IMPLY
LINGERING THREAT OF SHOWERS AND THUNDERSTORMS IN SOUTHERN AREAS
AND ESPECIALLY SOUTHEAST LINGERS TO ABOUT 8-10 PM.
THE WINDS BECOME WEST TO NORTHWEST OVER MOST OF THE REGION DURING
THE EVENING HOURS...THE HIGH PW AIR IS GENERALLY CONFINED TO THE
SOUTHEAST AFTER ABOUT 7 PM THIS EVENING AND BY ABOUT 8 AM SUNDAY
THE PW VALUES ARE NORMAL ACROSS OUR ENTIRE REGION. THE FRONT WILL
BE SLOW TO CLEAR THE SOUTH EASTERN MOST AREAS UNTIL EARLY SUNDAY
MORNING. HAD TO HOLD SOME POPS IN ALONG SOUTHERN AREAS INTO EARLY
SUNDAY.
BEST NEWS IS THE 20C ISOTHERM AT 850 HPA IS GONE BEFORE 5 PM
THIS EVENING AND WE KICK THE 18C ISOTHERM OUT BY ABOUT 7 PM. BETTER
YET...WE WELCOME THE 12C ISOTHERM INTO THE STATE ABOUT 7 AM SUNDAY
AND LET IT SAG SOUTH DURING THE DAY SUNDAY. IT SHOULD BE A
SPECTACULARLY COMFORTABLE DAY SUNDAY. WITH LOW PW VALUES AND
COOLER TEMPERATURES. HOPEFULLY ANY CONVECTION WILL BE CLOSE TO THE
FRONT SOUTH OF THE MASON-DIXON LINE.
WE CAN SAY GOOD BY TO THE HEAT WAVE OF MID JULY 2013.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SUNDAY SHOULD BE A POST FRONTAL DAY WITH PW VALUES NEAR TO
SLIGHTLY BELOW NORMAL. THE LOWER TROPOSPHERIC TEMPERATURES WILL BE
NEAR NORMAL TOO. THE CHANCE FOR SHOWERS SHOULD BE LOW...WITH PERHAPS
THE HIGHEST CHANCE IN THE SOUTHERNMOST AREAS...CLOSE TO THE FRONTAL
BOUNDARY. OVERALL...SUNDAY IS LOOKING LIKE A VERY PLEASANT DAY FOR
MOST AREAS AS A WEAK AREA OF HIGH PRESSURE WILL BE OVER THE
REGION. THE LOWER HUMIDITY AND LOWER TEMPERATURES SHOULD BE
WELCOME RELIEF.
THE LOW-LEVEL FRONTAL BOUNDARY DOES NOT PUSH TOO FAR TO OUR
SOUTH. ANOTHER WAVE APPROACHES FROM THE WEST AND WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO
TUESDAY. THIS WILL INCREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS MONDAY NIGHT...WHICH MAY LINGER INTO TUESDAY.
NORTHWESTERLY FLOW WILL LIKELY PUSH A FRONT THROUGH THE REGION
AROUND MID-WEEK. THIS COULD INCREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS...MOST LIKELY ON WEDNESDAY. BEHIND THIS SECOND FRONT
THE PW VALUES DROP TO BELOW NORMAL...SHOULD BE VERY COMFORTABLE
THURSDAY AND FRIDAY BEHIND THIS FRONT SHOULD THESE FORECAST PROVE
CLOSE TO CORRECT.
OVERALL...THE MODELS AND ENSEMBLES ALL SHOW A TROUGH OVER THE
EASTERN USA MOST OF THE COMING WEEK IMPLYING COOLER AND RELATIVELY
DRIER WEATHER. BY MID-WEEK THE HEAT WAVE OF MID-JULY 2013 SHOULD
BE A FAINT MEMORY.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
A LINE OF CONVECTION CONTINUES TO MAKE ITS WAY THROUGH CENTRAL
PA. IFR CIGS AND VSBYS HAVE REACHED BFD...JST AND AOO. SHOWERS AND
THUNDERSTORMS WILL CONTINUE ALONG THE SOUTHERN HALF OF THE STATE
THROUGH MID MORNING. ANY SHOWERS AND THUNDERSTORMS SHOULD FALL
APART BY THEY REACH THE CENTRAL PART OF THE STATE AND SHOULD NOT
AFFECT MDT AND LNS. ANY STORMS SHOULD CONTINUE TILL 14Z...BEFORE
THEY FALL APART. EXPECT SHOWERS AND THUNDERSTORMS TO BE POSSIBLE THIS
AFTERNOON OUT AHEAD OF THE INCOMING COLD FRONT.
AS THE COLD FRONT CROSSES THE REGION LATE TODAY IT SHOULD TRIGGER
SCT STRONG TO POSSIBLY SEVERE STORMS. THE WIND SHIFT SHOULD OCCUR FROM
NW- SE BY SAT NIGHT. CLEARING SKIES WITH DRIER AIR SHOULD BUILD IN
BEHIND THE FRONT...LATE TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUE-WED...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/STEINBUGL
NEAR TERM...GRUMM/DANGELO
SHORT TERM...GRUMM
LONG TERM...GRUMM/CERU
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
449 PM EDT SAT JUL 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN OVER THE WEEKEND AS
A COLD FRONT MOVES SOUTHWARD FROM THE GREAT LAKES. THE FRONT WILL
STALL NORTH OF THE AREA ON SUNDAY AND THEN DISSIPATE OR RETURN
NORTHWARD INTO MONDAY. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL
DEVELOP OVER THE EAST ON TUESDAY AND LINGER THROUGH LATE WEEK. A
SECOND WEAK COLD FRONT WILL ARRIVE FROM THE NORTHWEST ON THURSDAY
AND SETTLE JUST SOUTHEAST OF THE REGION THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
400 PM UPDATE...STORMS EXTEND ACRS THE PIEDMONT ATTM...ALIGNED ALONG
MERGED GUST FRONT. SEEMS THERE IS JUST ENOUGH WLY UNIDIRECTIONAL
FLOW TO ALLOW THE STORMS TO ORGANIZE IN THIS WAY. WHILE THE LINE IS
ADVANCING SLOWLY INTO 3000 J/KG SBCAPE IT APPEARS THE GUST FRONT IS
OUTRUNNING IT. DOWNWARD TREND NOTED IN LIGHTNING FREQUENCY WITH
STORMS NEAR NC/SC BORDER. SO THE LINE MAY NOT PERSIST TOO MUCH
LONGER. THIS WOULD AGREE WITH LATEST HRRR ALSO. HOWEVER ISOLATED
CELLS ARE FORMING OVER CHARLOTTE METRO AND THE GUST FRONT MAY KICK
OFF SOME NEW ACTION OVER THE SC PIEDMONT. THUS AMPED UP POPS AHEAD
OF THE LINE DESPITE ITS WEAKENING...MAINTAINING CHANCE POPS N AND W
WHERE REDEVELOPMENT QUITE POSSIBLE. TRIED TO ADJUST TEMP TRENDS
WHICH HAVE BEEN AFFECTED BY THE COOL OUTFLOW...BUT THIS IS DIFFICULT
SO HAVE LOW CONFIDENCE IN TEMP FCST THRU EARLY EVENING.
AT 230 PM EDT SATURDAY...AN UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY
OVER THE EASTERN USA TONIGHT AND SUNDAY. A SHORTWAVE WILL MOVE INTO
THE BASE OF THIS TROUGH OVER THE TN RIVER VALLEY LATE SUNDAY. DEEP
GULF MOISTURE WILL BE TRANSPORTED NORTH INTO OUR AREA BY A GENTLE SW
LOW LEVEL FLOW ON THE WEST SIDE OF A BERMUDA HIGH...WHILE A COLD
FRONT DROPS SOUTH INTO VA. WITH LOW LEVEL FLOW NEARLY PARALLEL THE
TO THE BLUE RIDGE...UPSLOPE FLOW WILL BE LIMITED...THOUGH STILL
PRESENT. WITH THE LOWE LEVELS STABILIZING LATE THIS EVENING...
CONVECTIVE COVER SHOULD DIMINISH. MODEL SOUNDINGS SHOW CAPE
SURPASSING 1000 J/KG AGAIN ON SUNDAY...AND CONVECTIVE TRENDS ARE
EXPECTED TO MIMIC TODAY...WITH THE GREATEST COVERAGE IN THE
MOUNTAINS...WITH ACTIVITY SPREADING EAST INTO THE FOOTHILLS AND
PIEDMONT WITH TIME. SHEAR WILL REMAIN WEAK HOWEVER...LIMITING STORM
ORGANIZATION. MINIMUM TEMPERATURES WILL BE SEVERAL DEGREES ABOVE
NORMAL TONIGHT IN A MOIST AIR MASS. MAXIMUM TEMPERATURES SUNDAY WILL
BE SLIGHTLY BELOW NORMAL...WITH CLOUDS...MOISTURE A FALLING HEIGHTS
ALOFT LIMITING WARMING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AT 230 PM SATURDAY... 500 MB HEIGHTS GRADUALLY LOWER OVER THE
SOUTHEAST MONDAY AND TUESDAY BUT SURFACE PATTERN CHANGES WILL BE
RATHER SUBTLE. DIURNAL CONVECTION WILL CONTINUE INTO THE FORECAST
PERIOD BEGINNING 00Z MONDAY THEN GRADUALLY DIMINISH DURING THE
NIGHT. MOIST AND MODERATELY UNSTABLE AIR MASS WILL CONTINUE OVER THE
REGION AND GFS DEPICTS SHORT WAVE TROUGH APPROACHING CWA BY 12Z
MONDAY... SO AT LEAST SLIGHT CHANCE POPS WILL CONTINUE WELL INTO THE
NIGHT. DURING DAYTIME MONDAY... CWA REMAINS IN AIRMASS CONDUCIVE TO
CONVECTIVE STORM DEVELOPMENT SO POPS WILL INCREASE WITH DAYTIME
HEATING INTO CHANCE CATEGORY WITH LIKELY POPS OVER HIGHER TERRAIN.
GFS HAS ANOTHER SHORT WAVE TROUGH DROPPING INTO LONG WAVE TROUGH
POSITION EARLY TUESDAY... SO CHANCE POPS WILL CONTINUE THROUGH THE
NIGHT AND INTO TUESDAY WHEN DIURNAL HEATING CYCLE ONCE AGAIN LEADS
TO HIGHER PROBABILITIES DURING AFTERNOON. NO SIGNIFICANT TEMPERATURE
CHANGES WILL OCCUR DURING MONDAY TUESDAY. HIGHS OUTSIDE THE
MOUNTAINS WILL BE IN THE UPPER 80S AND LOWER 90S WHILE MOUNTAIN
VALLEY TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 80S. VERY WARM
LOW TEMPERATURES IN THE 60S AND LOWER 70S ARE EXPECTED TO CONTINUE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM SATURDAY... FLOW PATTERN ACROSS U.S. DURING THE PERIOD
WILL CONSIST OF RIDGE IN THE WEST AND TROUGH OVER THE EASTERN
STATES. BOUNDARY LAYER WILL REMAIN WARM AND MOIST SO COOL
TEMPERATURES ALOFT ON WEDNESDAY WILL SUPPORT LAPSE RATES
SUFFICIENTLY STEEP TO PROMOTE CONVECTION WITH APPROACH AND PASSAGE
EARLY THURSDAY OF COLD FRONT. THEREAFTER DETAILS BECOME DIFFICULT TO
RESOLVE AS FRONT DRIFTS SLOWLY SOUTHEAST AND APPEARS IN CURRENT
GUIDANCE TO BECOME NEARLY STATIONARY JUST AFTER CROSSING CWA.
THUS... AIR MASS CHANGE WILL NOT BE SUFFICIENTLY SIGNIFICANT TO
ELIMINATE POPS BUT NUMBERS WILL BE IN THE LOWER END OF THE CHANCE
SPECTRUM AND WILL DISPLAY A DIURNAL TREND. NO SIGNIFICANT CHANGES IN
TEMPERATURE EXPECTED.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
AT KCLT /21Z UPDATE/...A BLEND OF MAV AND MET GUIDANCE SUPPORTS MVFR
FOG AT DAYBREAK SUNDAY. GUIDANCE WAS ALL OVER THE PLACE ON CIGS...SO
A NEARLY PERSISTENCE FORECAST WAS USED...TAKING THE CIG DOWN TO THE
LOW END OF MVFR BY DAYBREAK. THUNDERSTORM COVERAGE WARRANTS A
MENTION IN THE TAF THIS AFTERNOON...WITH POSSIBLE MVFR VSBY AND CIG
RESTRICTIONS. DIFFICULT TO TELL AT THIS POINT IF BEST TSTM CHANCES
COME WITH THE LINE SLOWLY PROGRESSING INTO THE PIEDMONT OR FROM
ISOLATED CELLS AHEAD OF IT. WILL EXTEND TEMPO A BIT LATER GIVEN
CURRENT TRENDS. WINDS WILL REMAIN LIGHT FROM THE SW EXCEPT DURING TS
OUTFLOW EFFECTS THIS AFTN...WHICH WILL MOST LIKELY CAUSE A BRIEF
PERIOD OF NW GUSTS UP TO 20-25 KT.
ELSEWHERE...MODEL GUIDANCE IS SUPPORTIVE OF DAYBREAK MVFR FOG SUNDAY
MORNING AT ALL FOOTHILLS SITES EXCEPT KGMU...AND SUPPORTS IFR FOG AT
KAVL. GUIDANCE VARIED WILDLY ON CIGS...SO A NEAR PERSISTENCE
FORECAST WAS USED...TAKING FOOTHILL SITES DOWN TO LOW END MVFR..AND
KAVL BACK DOWN TO LIFR. CONVECTIVE CHANCES SUPPORT CARRYING THUNDER
IN THE TAFS THIS AFTERNOON. LIGHT WINDS WILL PERSIST FROM THE
SW...EXCEPT AT KAVL WHERE THEY WILL VEER TO NW LATE TONIGHT.
OUTLOOK...A COLD FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND.
EXPECT ABOVE NORMAL TSRA COVERAGE SUNDAY AND INTO EARLY NEXT
WEEK...WITH BEST CHANCES STILL DURING AFTERNOONS AND EVENINGS.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 89% MED 69% HIGH 83%
KGSP HIGH 100% HIGH 89% MED 66% HIGH 83%
KAVL HIGH 100% HIGH 89% MED 64% MED 65%
KHKY HIGH 100% HIGH 88% LOW 50% MED 67%
KGMU HIGH 100% HIGH 89% MED 70% MED 67%
KAND HIGH 98% HIGH 88% MED 70% HIGH 83%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...LGL
LONG TERM...LGL
AVIATION...JAT/WIMBERLEY
=
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
319 PM CDT SAT JUL 20 2013
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
SEVERAL WEAK SHORT WAVES EMBEDDED WITHIN THE NORTHWEST FLOW ALOFT
WILL BRING ISOLATED TO SCATTERED THUNDERSTORMS ACROSS THE REGION
THIS EVENING THOUGH SUNDAY. WITH HI-RES MODELS STRUGGLING TO
DEPICT THE AREAS OF CONVECTION...WITH MAINTAIN AT LEAST A LOW POP
THROUGH 18Z SUNDAY.
AS OF 19Z...A NARROW LINE OF SHOWERS ARE MOVING SE ACROSS
HYDE/HAND COUNTY. THESE STORMS SHOULD CONTINUE TO DISSIPATE AS THEY
EXIT THIS CWA. FARTHER WEST...A MORE PRONOUNCED SHORT WAVE HAS
CAUSED CONVECTION A DEVELOP OVER THE BLACK HILLS. THIS AREA IS
BASICALLY UNCAPPED WITH SB-CAPE VALUES AROUND 2000 J/KG. THESE
STORMS SHOULD CONTINUE TO GROW AS SOUTH TO EASTERLY LOW LEVEL FLOW
WILL FILTER MOISTURE INTO SW SOUTH DAKOTA. WOULD EXPECT THESE
STORM WILL REMAIN JUST SOUTH OF THE CWA AS THE LAYER STORM MOTION
OFF THE RUC SUGGEST A SE MOTION. THAT SAID...SEVERAL OUTFLOW
BOUNDARIES FROM EARLIER CONVECTION COULD RESULT IN A NORTHWARD
JOG.
CHANCES FOR THUNDERSTORMS IN THE EASTERN CWA TONIGHT/SUNDAY IS A
LITTLE UNCLEAR AT THIS TIME. HALF THE MODEL SUGGEST LLJ INDUCED
THUNDERSTORMS MOVING ACROSS THE EASTERN DAKOTAS BY 12Z. OTHERS
SUGGEST CONVECTION COULD BE SOUTH/EAST/OR NORTH OF THIS CWA. WITH
VERY LOW CONFIDENCE...WILL BROAD BRUSH MOST OF THE CWA WITH LOW
POPS FOR NOW ON SUNDAY.
AN AREA OF LOW PRESSURE AND SURFACE COLD FRONT WILL MOVE ACROSS
THE REGION ON SUNDAY NIGHT/MONDAY MORNING. WITH THE MAJORITY OF
THE PCPN FALLING POST FRONTAL...SEVERE STORMS DO NOT APPEAR
POSSIBLE. COOLER TEMPERATURES ARE EXPECTED ON MONDAY WITH HIGHS IN
THE UPPER 70S..IN THE NE...TO AROUND 90 IN THE SOUTHWEST CWA. A
BLEND OF CONSALL/ALLBLEND SHOWS HIGHS COULD BE SLIGHTLY COOLER
THAN CURRENTLY ADVERTISED.
.LONG TERM...TUESDAY THROUGH SATURDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THROUGH THE EXTENDED. MAIN
FORECAST CHALLENGE WILL BE TIMING SHORTWAVE ACTIVITY. THE PATTERN
WILL REMAIN VERY ACTIVE THROUGH THURSDAY WITH A SERIES OF
SHORTWAVES. TIMING AND INTENSITY ARE VERY DIFFICULT TO DETERMINE
AT THIS TIME RANGE SO CONFIDENCE IN POPS IN ANY GIVEN PERIOD IS
LOW. THAT SAID TUESDAY NIGHT DOES SEEM TO HAVE MODEL AGREEMENT ON
BEING DRY WHILE THURSDAY HAS BEEN CONSISTENTLY STORMY. STUCK CLOSE
TO ALLBLEND POPS BECAUSE OF UNCERTAINTY. BY FRIDAY SFC HIGH
PRESSURE BEGINS TO DROP OUT OF CANADA AND NOSE INTO EASTERN SD.
THE START OF THE WEEKEND APPEARS DRY FOR NOW AS A RESULT.
TEMPERATURES WILL BE MUCH COOLER THROUGH THE PERIOD WITH HIGHS
RANGING FROM THE UPPER 70S IN THE EAST TO THE MID 80S IN THE
SOUTHWEST.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL. ISOALTED SHOWERS AND TSTORMS ARE
CONTINUING THIS AFTERNOON BUT HAVE MANAGED TO AVOID THE TAF SITES.
STORMS MAY BECOME MORE WIDESPREAD IN THE WEST THIS EVENING SO LEFT
IN THE VCTS MENTION AT KMBG/KPIR FOR AFTER 00Z. HI-RES MODELS
INDICATE THE EAST MAY SEE AN ISOLATE STORM OR TWO THIS EVENING AS
WELL BUT LOCATION AND TIMING ARE TOO DIFFICULT TO PINPOINT. MAY
NEED TO ADD VCTS AT SOME POINT TO KATY/KABR BUT LEFT OUT FOR NOW.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SD
LONG TERM...WISE
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1137 PM CDT FRI JUL 19 2013
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
A FEW SHOWERS CONTINUE NEAR THE KJCT TERMINAL AND MAY CONTINUE FOR
A FEW MORE HOURS OVERNIGHT IN AN AREA OF MODEST LARGE SCALE ASCENT
AND WEAK LOW LEVEL WARM ADVECTION. THE DEVELOPMENT OF CLOUDS IN
THE 6-10 KFT LAYER MAY PRECLUDE LOW CLOUDS OVERNIGHT BUT I DID NOT
WANT TO REMOVE THEM JUST YET. WILL LET THE NEXT SHIFT MONITOR THE
TRENDS OVERNIGHT. IF LOW CLOUDS DO FORM...THE ARE EXPECTED TO
RANGE BETWEEN 1-2 KFT AT KJCT/KSOA AND COULD BRIEFLY AFFECT
KSJT/KBBD AFTER SUNRISE AS THE STRATO CU BEGINS TO DEVELOP.
OTHERWISE...EXPECT VFR CONDITIONS WITH A GENERALLY SOUTHERLY WIND
AT 10 KTS OR LESS.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 938 PM CDT FRI JUL 19 2013/
UPDATE...
ADDED ISOLATED SHOWERS OVER FAR SOUTHERN SECTIONS AND MADE MINOR
TWEAKED TO DEWPOINTS AND SKY COVER FOR THE REST OF TONIGHT.
DISCUSSION...
LATEST NAM AND HRRR ARE INDICATING SOME LIGHT RAIN SHOWERS
DEVELOPING ACROSS PORTIONS OF THE NORTHWEST HILL COUNTRY AND
NORTH EDWARDS PLATEAU AFTER 03Z. THIS SEEMS TO BE TIED TO SOME
ENHANCED LOW LEVEL MOISTURE ADVECTION AND WEAK CONVERGENCE ACROSS
THIS AREA. ADDED ISOLATED RAIN SHOWERS ACROSS SOUTHERN COUNTIES
FOR THE OVERNIGHT PERIOD AND TWEAKED DEWPOINTS AND SKY COVER TO
ACCOUNT FOR TRENDS. UPDATED PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 620 PM CDT FRI JUL 19 2013/
DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
A FEW DIURNAL SHOWERS HAVE DEVELOPED TO THE NORTH OF KABI AND
SOUTHEAST OF KJCT BUT I EXPECT MOST OF THIS TO DISSIPATE WITHIN
THE NEXT 1-2 HOURS AS WE LOSE DAYTIME HEATING. THE CU FIELD WILL
HOLD ON FOR A FEW HOURS BUT SHOULD THIN OVERNIGHT. THERE IS SOME
INDICATION IN THE NAM AND HRRR MODELS THAT NOCTURNAL SHOWERS COULD
DEVELOP SOUTH OF A KSJT TO KBBD LINE TONIGHT BUT CONFIDENCE IS
VERY LOW SO THE TAFS MAINTAIN NO MENTION OF PRECIP. HIGH CLOUDS
WILL CONTINUE TO STREAM FROM THE NORTHWEST TO SOUTHEAST OVERNIGHT
BUT LOW CLOUDS WILL BE THE PRIMARY CONCERN...ESPECIALLY SOUTH OF
KSJT AND KBBD.
PATCHY FOG WILL BE POSSIBLE INTI ALLY TONIGHT...MAINLY AFTER
06Z...WITH STRATUS DEVELOPING AT BOTH KSOA AND KJCT NEAR OR BEFORE
12Z. FARTHER NORTH...WE COULD SEE AN HOUR OR TWO OF MVFR
CONDITIONS AS STRATO CU DEVELOP AFTER SUNRISE...CLOSER TO 14-15Z.
BY 15-16Z...VFR CONDITIONS ARE ANTICIPATED ACROSS WEST CENTRAL
TEXAS WITH AN AFTERNOON CU FIELD AROUND 6 KFT. GENERALLY SOUTH
WINDS ARE EXPECTED TO REMAIN AROUND 10 KTS OR LESS...FOLLOWING OUR
TYPICAL DIURNAL TREND OF VEERING TO THE SOUTHWEST IN THE MORNING
AND BACKING TO THE SOUTHEAST DURING THE LATE AFTERNOON AND EVENING
HOURS.
JOHNSON
PREV DISCUSSION... /ISSUED 340 PM CDT FRI JUL 19 2013/
SHORT TERM...
MUCH QUIETER PATTERN ACROSS WEST CENTRAL TEXAS THIS AFTERNOON...
WEST CENTRAL TEXAS IS BETWEEN SYSTEMS THIS AFTERNOON...WITH THE
UPPER LOW THAT BROUGHT MUCH NEEDED RAINFALL TO THE AREA NOW ACROSS
NORTHWEST MEXICO...AND A SECOND UPPER LOW WORKING ITS WAY INTO
LOUISIANA. SUBSTANTIAL CUMULUS FIELD ACROSS THE AREA THIS
AFTERNOON...BUT THIS CLOUD COVER IS NOT LEADING TO ANY SHOWERS OR
STORMS. VERY LITTLE ENHANCEMENT TO THIS CU FIELD...SO CHANCES OF
ANY DEVELOPMENT ARE SMALL...BUT NOT ZERO...THROUGH SUNSET.
THERE IS CONVECTION ACROSS EAST TEXAS FROM THE LOUISIANA SYSTEM
ACROSS EAST TEXAS THIS AFTERNOON...AND EXPECT IT TO MAKE A RUN
TOWARDS THE HEARTLAND BY SATURDAY AFTERNOON. HOWEVER...LATEST
GLOBAL MODELS AND THE TTU WRF SUGGEST IT WONT QUITE MAKE IT.
WILL KEEP POPS OUT OF THE FORECAST FOR NOW. OTHERWISE...WARM AND
MOIST AIR MASS TO REMAIN IN PLACE. A LITTLE MORE SUN IS ALLOWING
TEMPERATURES TO CLIMB THIS AFTERNOON...AND MORE OF THE SAME FOR
SATURDAY.
LONG TERM...
/SUNDAY THROUGH FRIDAY/
THE MAIN QUESTION IN THE LONG TERM IS WHAT EFFECTS THE RECENT
RAINFALL WILL HAVE ON TEMPERATURES. BUT FIRST...THERE IS A VERY
SLIGHT CHANCE FOR RAIN SUNDAY NIGHT AS A WEAKNESS IN THE RIDGE
DEVELOPS. ALL OF THE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE
WEAKNESS DEVELOPING OVER WEST TEXAS AND A LOW DEVELOPING OVER
NORTHERN MEXICO. PREVIOUS MODEL RUNS WERE SUGGESTING THE RAIN
WOULD BE ON MONDAY. LOOKING AT THE GFS ENSEMBLES 12 HOUR RAIN
PROBABILITIES...IT HAS SLIGHTLY BETTER CHANCES SUNDAY NIGHT AND
BACKS OFF FOR MONDAY. THE ECMWF DETERMINISTIC MODEL IS SLIGHTLY
WETTER THAN THE GFS. GIVEN THE LACK OF MUCH SUPPORT AT THE SURFACE
TO INITIATE ANYTHING...I AM GOING WITH MORE OF THE GFS...NAM
SOLUTION AND HAVE SOME SLIGHT CHANCES ACROSS THE NORTHERN EDWARDS
PLATEAU AND NORTHWEST HILL COUNTRY SUNDAY NIGHT.
OTHERWISE...THE RIDGE BUILDS BACK IN AND TEMPERATURES WARM THROUGH
THE END OF NEXT WEEK AS WE BEGIN TO DRY OUT. THE AIR SHOULD STAY
FAIRLY MOIST AS IT WILL TAKE A WHILE FOR THE THE SOIL MOISTURE TO
RETURN TO A MORE NORMAL LEVEL FOLLOWING THE RAIN THIS WEEK. WINDS
WILL STAY OUT OF THE SOUTH TO SOUTHEAST...SO I WOULD NOT EXPECT TO
SEE RAPID DRYING. SOME OF THE MODEL GUIDANCE IS TRYING TO TAKE
TEMPERATURES JUST OVER 100 DEGREES...BUT THIS IS OVER THE AREA
THAT HAS RECEIVED THE HIGHER RAIN AMOUNTS. GIVEN THAT THE HIGHER
SOIL MOISTURE SHOULD HELP TO KEEP TEMPERATURES JUST A BIT
COOLER...I HAVE TENDED TEMPERATURES TOWARDS THE RAW GFS SOLUTION
WITH TEMPERATURES IN THE MID TO UPPER 90S.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 71 94 72 94 72 / 10 10 5 5 10
SAN ANGELO 69 93 71 94 71 / 10 10 5 10 10
JUNCTION 69 93 70 93 71 / 10 10 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1016 PM EDT SUN JUL 21 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL DRIFT SOUTHEAST TOWARD THE AREA TONIGHT
AND MONDAY...BEFORE LIFTING BACK TO THE NORTH ON TUESDAY. THE
PROXIMITY OF THIS FRONT WILL INCREASE THE THREAT FOR SHOWERS AND
THUNDERSTORMS THROUGH THE WORKWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 1000 PM EDT SUNDAY...
FOLLOWING CLOSE TO THE HRRR WHICH HIGHLIGHTS MORE THREAT OF
SHOWERS FROM SE WV EAST NORTHEAST INTO THE SOUTHERN SHENANDOAH
VALLEY OVERNIGHT BEFORE DIMINISHING. KEPT ISOLATED TO NONE IN THE
SOUTH. NOT MUCH CHANGE IN THE REST OF THE FORECAST AS WE SHOULD
SEE PATCHY FOG WITH MOSTLY CLOUDY SKIES.
OVERNIGHT LOWS WILL REMAIN ON THE MILD SIDE...GENERALLY FALLING
INTO THE MID 60S TO LOW 70S.
EXPECT GREATER COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY FOR
MONDAY AS A STRONGER UPPER LEVEL DISTURBANCE APPROACHES FROM THE
WEST. ONCE AGAIN...THE GREATEST THREAT NORTH OF INTERSTATE 81 WILL
BE LOCALLY HEAVY RAIN...WITH RAINFALL RATES OF AN INCH OR MORE
OVER A FEW MINUTES TIME. AS SUCH...WILL AGAIN BE CONCERNED WITH
LOCALIZED FLASH FLOODING. WILL LEAVE THE DECISION OF THE TIMING
AND LOCATION OF A FLASH FLOOD WATCH TO THE OVERNIGHT
SHIFT...GIVING THEM AN OPPORTUNITY TO LOOK AT ANOTHER SET OF
SYNOPTIC WEATHER MODELS. SOUTH OF INTERSTATE 81...WILL ALSO SEE A
SLIGHTLY GREATER THREAT OF STRONG TO SEVERE THUNDERSTORMS DURING
THE AFTERNOON AND EVENING DUE TO STRONGER SURFACE HEATING. STUCK
PRETTY CLOSE TO MET GUIDANCE FOR AFTERNOON TEMPERATURES...WITH
HIGHS REACHING THE UPPER 70S AND LOW 80S WEST...AND REACHING TO
AROUND 90 ACROSS THE PIEDMONTS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 340 PM EDT SUNDAY...
WELL DEFINED SHORT WAVE CROSSES THE FORECAST AREA MONDAY NIGHT AND
TUESDAY. THIS WILL KEEP A BETTER PROBABILITY OF PRECIPITATION
OVERNIGHT THAN JUST THE TYPICAL DIURNAL CYCLE OF THE PAST FEW DAYS.
UPPER TROF AMPLIFIES ENOUGH THAT THE FRONT WILL PUSH SOUTH OF THE
FORECAST AREA ON WEDNESDAY. AS THE FRONT COMES THROUGH ON WEDNESDAY
THE EXPECTING MORE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS IN
THE AFTERNOON AND EVENING. WITH THE PASSAGE OF THE SHORT WAVE...MID
LEVEL TEMPERATURES COOL SLIGHTLY WHICH WILL ENHANCE THE LAPSE RATES
AND INSTABILITY.
LITTLE CHANGE IN DAILY HIGH AND LOW TEMPERATURES AND IN MOISTURE OF
THE AIR MASS. STAYED CLOSE TO MODEL GUIDANCE FOR MAXIMUM AND MINIMUM
TEMPERATURES EACH DAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 1140 AM EDT SUNDAY...
NO CHANGE IN THE OVERALL PATTERN THROUGH THE EXTENDED PERIOD. MODELS
BRINGING STRONG ENOUGH SHORT WAVE THROUGH THE EASTERN UPPER TROF ON
THURSDAY TO PUSH A SURFACE FRONT INTO THE SOUTHEAST STATES. THIS
WOULD BRING WINDS AROUND TO THE NORTHWEST AND NORTH. MAY NOT
COMPLETELY ELIMINATE THE PROBABILITY OF PRECIPITATION FOR THE
FORECAST AREA...BUT CHANCES ON THURSDAY AND FRIDAY SHOULD BE LESS
THAN IN RECENT DAYS. SOME SIGNS IN THE MODELS OF ACTUAL DRIER AIR
REACHING THE FORECAST AREA. SUBTLE DROP IN 850 MB TEMPERATURES
BEHIND THE FRONT...OTHERWISE NEAR NORMAL FOR HIGHS AND LOWS THROUGH
DAY 7/SUNDAY.
SURFACE LOW PRESSURE OVER THE MISSISSIPPI VALLEY ON SATURDAY WILL
APPROACH THE REGION BY SUNDAY. WINDS WILL BE BACK AROUND TO THE
SOUTHWEST WITH DEEP MOISTURE RETURNING AHEAD OF THE LOW.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
AS OF 730 PM EDT SUNDAY...
STILL WATCHING SHOWERS AND A FEW STORMS ACROSS MAINLY THE WESTERN
FORECAST AREA. HAVE VCTS AT ROA/BCB AS A COUPLE OF STORMS WERE
MOVING ACROSS CRAIG AND GILES COUNTY...ALTHOUGH THE GILES COUNTY
CELL IN THE LAST 5 MINUTES HAS WEAKENED. STILL APPEARS BEST
COVERAGE OF SHOWERS THIS EVENING WILL BE IN THE BLF-LWB CORRIDOR.
AS WE HEAD INTO THE OVERNIGHT THE CHANCES OF SHOWERS DECREASES AND
WILL MAINTAIN PERSISTANCE ON THE FORECAST FROM PREVIOUS ONE...AND
HIT THE FOG HERE AT BCB AND IN LWB THE HARDEST. APPEARS THERE MAY
BE ENOUGH COVERAGE OF CLOUDS TO KEEP FOG FROM BECOMING TOO MUCH OF
AN ISSUE ELSEWHERE...BUT STILL MVFR TO IFR POSSIBLE...ALONG WITH
POTENTIAL LOW CIGS AT BLF/LWB/BCB.
COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY LOOKS BETTER MONDAY
AND EVEN THOUGH THIS IS LIKELY...KEPT VCTS IN THE TAFS AND
PREDOMINAT SHOWERS...AS MODELS STILL SHWOING AT LEAST SOME PERIODS
OF LESS COVERAGE MAINLY EAST OF THE BLUE RIDGE. MAIN CONCERNS
WITH THIS DISTURBANCE WILL AGAIN BE HEAVY RAIN...RESULTING IN
PERIODIC IFR CONDITIONS AT ALL AIRPORTS. A FEW SEVERE STORMS WILL
ALSO BE POSSIBLE...MORE SO FOR DAN AND LYH WHERE STRONGER DAYTIME
HEATING WILL ADD TO ATMOSPHERIC INSTABILITY DURING THE AFTERNOON.
MODELS CONTINUE TO DEPICT THE STALLED FRONT HOLDING JUST NORTH OF
THE AREA THROUGH EARLY TUESDAY...BEFORE LIFTING AS A LOW PRESSURE
SYSTEM MOVES ACROSS THE WESTERN GREAT LAKES. REGARDLESS...EXPECT
DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS TO PERSIST THROUGH THE
COMING WORKWEEK AS GULF MOISTURE REMAINS ABUNDANT ACROSS THE AREA.
ANOTHER COLD FRONT WILL APPROACH THE OHIO RIVER TOWARD THE END OF
THE WORKWEEK...BUT DO NOT SEE THE FRONT ADVANCING MUCH FURTHER
SOUTH THAN THAT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...NF/WP
SHORT TERM...AMS/RCS
LONG TERM...AMS
AVIATION...NF/WP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
601 PM CDT SAT JUL 20 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SECONDARY
COLD FRONT STRETCHING FROM CENTRAL NORTH DAKOTA TO PORT WASHINGTON
TO SOUTHERN LOWER MICHIGAN. SEVERAL SHORTWAVES NOTED ON WV IMAGERY
FROM WESTERN WISCONSIN TO NORTH DAKOTA. THE SHORTWAVE OVER WESTERN
WISCONSIN MAY BE HELPING A FEW SHOWERS POP JUST WEST OF THE FOX
VALLEY THIS AFTERNOON EVEN WITHOUT MUCH INSTABILITY AND NORTH OF THE
FRONTAL BOUNDARY. WILL KEEP AN ISOLATED POP MENTION OVER NORTHEAST
WISCONSIN FOR THE REST OF THE AFTERNOON. PRETTY QUIET UPSTREAM UNTIL
YOU REACH THE DAKOTAS. WITH SEVERAL SHORTWAVES TO PASS OVER THE
REGION...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...LAST NIGHTS COLD FRONT WILL SETTLE FROM THE NORTHERN
PLAINS TO FAR NORTHEAST ILLINOIS. THE 850MB FRONT WILL STALL
FARTHER NORTH OVER CENTRAL WISCONSIN WHERE SEVERAL WEAK RIPPLES
UPSTREAM WILL PASS OVER WITHIN WNW FLOW ALOFT. WEAK FGEN ALSO NOTED
ALONG THE FRONT IN THE MODELS...BUT MODELS ARE ALSO VERY GENEROUS IN
CREATING QPF ALONG THE FRONT TODAY...WHICH HAS NOT VERIFIED WELL.
GIVEN VERY WEAK FORCING AND LITTLE TO NO INSTABILITY TONIGHT...AM
NOT ENTHUSIASTIC ABOUT PRECIP CHANCES AND WILL LEAVE THE FORECAST
AREA DRY TONIGHT EXCEPT FOR VERY LATE WHEN A FEW SPRINKLES OR LIGHT
SHOWERS ARE POSSIBLE OVER CENTRAL WISCONSIN WHERE MOISTURE GETS A
LITTLE MORE DEEPER THAN THE REST OF THE AREA. PLENTY OF MID CLOUDS
UPSTREAM SO INCREASED SKY COVER...AND THEREFORE MIN TEMPS AS WELL.
LOWS FROM THE MID 40S NORTH TO UPPER 50S SOUTH.
SUNDAY...A LITTLE STRONGER SHORTWAVE WILL SWING ACROSS THE NORTHERN
MISSISSIPPI VALLEY AND INTO SOUTHWEST WISCONSIN IN THE AFTERNOON.
FORCING WILL REMAIN ON THE WEAKER SIDE...BUT WILL IMPROVE MARGINALLY
THROUGH THE DAY WITH THE APPROACH OF THE SHORTWAVE. WILL KEEP POPS
WEST OF THE FOX VALLEY AND INCREASE THEM A BIT OVER CENTRAL
WISCONSIN FOR THE AFTERNOON. IF SUFFICIENT BREAKS IN THE CLOUDS
OCCUR SO TEMPS CAN REACH INTO THE MID 70S...CAPES MAY REACH INTO
THE 500-700 J/KG RANGE OVER CENTRAL. SO CANNOT RULE OUT THUNDER
CONSIDERING THUNDERSTORMS ARE OCCURRING UPSTREAM OVER THE PLAINS.
HIGHS IN THE LOW TO MID 70S UNDER PARTLY TO MOSTLY CLOUDY CONDITIONS.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
AREA REMAINS UNDER NW UPPER FLOW DURING THE PERIOD AS SHORTWAVE
TROFS MOVE THROUGH MEAN LONGWAVE TROF OVER E NOAM. STRONGEST OF
THE SHORTWAVES MOVES THROUGH LATE MONDAY. SUFFICIENT INSTABILITY
AND SHEAR FOR THUNDERSTORMS WITH GUSTY WINDS AHEAD OF ASSOCIATED
COLD FRONT LATE MONDAY INTO MONDAY EVENING.
BIGGEST QUESTION IS AMOUNT OF PRECIP IN WAA AHEAD OF THAT SYSTEM.
GFS A BIT MORE AGRESSIVE WITH ELEVATED INSTABILITY AND APPEARS TO
SUFFER FROM SOME CONVECTIVE FEEDBACK OVER S WISC LATE SUNDAY.
REGARDLESS... SCATTERED SHOWERS OR STORMS EXPECTED LATE SUNDAY
ASSOCIATED WITH LIFT IN WAA ZONE.
COOL AIR MOVES INTO REGION BEHIND THE LATE MONDAY COLD FRONT...WITH
LOW TEMPS BY TUE NIGHT FALLING WELL INTO THE 40S ACROSS THE FAR
NORTH. WENT BELOW GUIDANCE MINS FOR THE PERIOD.
TEMP FORECAST FOR THE REMAINDER OF THE PERIOD A BLEND OF BEST
PERFORMING MODEL GUIDANCE. OUTSIDE OF TUE MAX TEMPS...MUCH OF
PERIOD WILL HAVE TEMPS AOB NORMS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 601 PM CDT SAT JUL 20 2013
MID LEVEL VFR CLOUDS WILL CONTINUE TO PASS OVER THE
AREA TONIGHT INTO SUNDAY. PATCHY MVFR CIGS MAY DEVELOP LATER
SUNDAY AFTERNOON OVER CENTRAL WISCONSIN WITH AREAS OF LIGHT RAIN.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SECONDARY
COLD FRONT STRETCHING FROM CENTRAL NORTH DAKOTA TO PORT WASHINGTON
TO SOUTHERN LOWER MICHIGAN. SEVERAL SHORTWAVES NOTED ON WV IMAGERY
FROM WESTERN WISCONSIN TO NORTH DAKOTA. THE SHORTWAVE OVER WESTERN
WISCONSIN MAY BE HELPING A FEW SHOWERS POP JUST WEST OF THE FOX
VALLEY THIS AFTERNOON EVEN WITHOUT MUCH INSTABILITY AND NORTH OF THE
FRONTAL BOUNDARY. WILL KEEP AN ISOLATED POP MENTION OVER NORTHEAST
WISCONSIN FOR THE REST OF THE AFTERNOON. PRETTY QUIET UPSTREAM UNTIL
YOU REACH THE DAKOTAS. WITH SEVERAL SHORTWAVES TO PASS OVER THE
REGION...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...LAST NIGHTS COLD FRONT WILL SETTLE FROM THE NORTHERN
PLAINS TO FAR NORTHEAST ILLINOIS. THE 850MB FRONT WILL STALL
FARTHER NORTH OVER CENTRAL WISCONSIN WHERE SEVERAL WEAK RIPPLES
UPSTREAM WILL PASS OVER WITHIN WNW FLOW ALOFT. WEAK FGEN ALSO NOTED
ALONG THE FRONT IN THE MODELS...BUT MODELS ARE ALSO VERY GENEROUS IN
CREATING QPF ALONG THE FRONT TODAY...WHICH HAS NOT VERIFIED WELL.
GIVEN VERY WEAK FORCING AND LITTLE TO NO INSTABILITY TONIGHT...AM
NOT ENTHUSIASTIC ABOUT PRECIP CHANCES AND WILL LEAVE THE FORECAST
AREA DRY TONIGHT EXCEPT FOR VERY LATE WHEN A FEW SPRINKLES OR LIGHT
SHOWERS ARE POSSIBLE OVER CENTRAL WISCONSIN WHERE MOISTURE GETS A
LITTLE MORE DEEPER THAN THE REST OF THE AREA. PLENTY OF MID CLOUDS
UPSTREAM SO INCREASED SKY COVER...AND THEREFORE MIN TEMPS AS WELL.
LOWS FROM THE MID 40S NORTH TO UPPER 50S SOUTH.
SUNDAY...A LITTLE STRONGER SHORTWAVE WILL SWING ACROSS THE NORTHERN
MISSISSIPPI VALLEY AND INTO SOUTHWEST WISCONSIN IN THE AFTERNOON.
FORCING WILL REMAIN ON THE WEAKER SIDE...BUT WILL IMPROVE MARGINALLY
THROUGH THE DAY WITH THE APPROACH OF THE SHORTWAVE. WILL KEEP POPS
WEST OF THE FOX VALLEY AND INCREASE THEM A BIT OVER CENTRAL
WISCONSIN FOR THE AFTERNOON. IF SUFFICIENT BREAKS IN THE CLOUDS
OCCUR SO TEMPS CAN REACH INTO THE MID 70S...CAPES MAY REACH INTO
THE 500-700 J/KG RANGE OVER CENTRAL. SO CANNOT RULE OUT THUNDER
CONSIDERING THUNDERSTORMS ARE OCCURRING UPSTREAM OVER THE PLAINS.
HIGHS IN THE LOW TO MID 70S UNDER PARTLY TO MOSTLY CLOUDY CONDITIONS.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
AREA REMAINS UNDER NW UPPER FLOW DURING THE PERIOD AS SHORTWAVE
TROFS MOVE THROUGH MEAN LONGWAVE TROF OVER E NOAM. STRONGEST OF
THE SHORTWAVES MOVES THROUGH LATE MONDAY. SUFFICIENT INSTABILITY
AND SHEAR FOR THUNDERSTORMS WITH GUSTY WINDS AHEAD OF ASSOCIATED
COLD FRONT LATE MONDAY INTO MONDAY EVENING.
BIGGEST QUESTION IS AMOUNT OF PRECIP IN WAA AHEAD OF THAT SYSTEM.
GFS A BIT MORE AGRESSIVE WITH ELEVATED INSTABILITY AND APPEARS TO
SUFFER FROM SOME CONVECTIVE FEEDBACK OVER S WISC LATE SUNDAY.
REGARDLESS... SCATTERED SHOWERS OR STORMS EXPECTED LATE SUNDAY
ASSOCIATED WITH LIFT IN WAA ZONE.
COOL AIR MOVES INTO REGION BEHIND THE LATE MONDAY COLD FRONT...WITH
LOW TEMPS BY TUE NIGHT FALLING WELL INTO THE 40S ACROSS THE FAR
NORTH. WENT BELOW GUIDANCE MINS FOR THE PERIOD.
TEMP FORECAST FOR THE REMAINDER OF THE PERIOD A BLEND OF BEST
PERFORMING MODEL GUIDANCE. OUTSIDE OF TUE MAX TEMPS...MUCH OF
PERIOD WILL HAVE TEMPS AOB NORMS.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1231 PM CDT SAT JUL 20 2013
MID-LEVEL CLOUDS ALONG A STALLED COLD FRONT WILL GRADUALLY LOWER
OVER THE NEXT 24 HOURS. THINK VFR CONDITIONS WILL HOLD OUT
THOUGH...EVEN IF LIGHT SHOWERS MOVE INTO CENTRAL WISCONSIN
TOMORROW MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1240 PM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SAT JUL 20 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW
FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING
CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT
WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON.
THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS
ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID
CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS
OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY
TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE
THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING
SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA.
DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER
VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE
DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST
AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT.
TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF
THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB
TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z.
SYNOPTIC OVERVIEW...
A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD.
MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING
AND RIDING THROUGH THE NORTHWEST FLOW.
TODAY...
ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH
DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS
SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON.
CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS
MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE
WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A
LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST
SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS
TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE
POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS
TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH
RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE
MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A
VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM.
925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN
THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID
80S.
TONIGHT...
CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD
DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS
BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING
A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO
NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO
IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL
NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT
INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION
WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD
FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT.
HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH
850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME
SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER
HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE
TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE
THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING
THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF
PRECIPITATION IN THE 20-40 RANGE OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM CDT SAT JUL 20 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW
PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY
AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT
EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP
INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE
RIDGE FROM BUILDING UP INTO THE FORECAST AREA.
SUNDAY INTO MONDAY NIGHT...
THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO
TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE
SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING.
HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH
OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO
PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE
AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP
FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS
FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY
NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST
SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE
CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID
LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING.
20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY.
ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM
SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED
COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE
IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE
IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS
WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS.
925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS
HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE
THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH:
1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE
MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA.
2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF
THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT.
3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT
BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH.
GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE
40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE
QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST
HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR
VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS.
CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH.
TUESDAY THROUGH FRIDAY NIGHT...
DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY...
WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE
FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD
AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF
CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY
NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA
DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION
OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO
SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE
HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY.
850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE
MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A
STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND
HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS
VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A
MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO
SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE
MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE.
ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH
PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR
NEXT WEEKEND.
&&
.AVIATION...THROUGH 18Z SUNDAY
1240 PM CDT SAT JUL 20 2013
SOME REMNANT MID-HIGH CLOUD ACROSS THE TAF LOCATIONS AT MID-DAY...
LEFTOVER FROM STORMS THAT FIRED OVER SD. THIS SHOULD CLEAR BY MID-
AFTERNOON. MEANWHILE...ANOTHER BAND OF SHOWERS OVER WESTERN MN ARE
TRACKING THIS WAY. WEAK SHORT WAVE TROUGH ENERGY SEEN IN WATER
VAPOR IMAGERY EXPECTED TO CROSS THE AREA BY EVENING...AND ANOTHER
DISTURBANCE ANTICIPATED OVERNIGHT. SEVERAL WEAK BOUNDARIES LYING
AROUND THE REGION TO ASSIST ON FOCUSING CONVECTIVE POTENTIAL. THE
STRONGEST OF WHICH IS A COOL FRONT ADVANCING SOUTH-SOUTHWEST
ACROSS NORTHERN WI AND CENTRAL MN. EXPECT THE DISTURBANCE THIS
AFTERNOON WILL MAXIMIZE POTENTIAL DURING PEAK HEATING AND COULD
RESULT IN SHOWERS AND ISOLATED THUNDERSTORMS. BETTER CHANCES EXIST
OVER SOUTHEAST MN...BUT EVEN THAT IS REMOTE. THE SECOND WAVE
TONIGHT WILL BRING A BETTER AND MORE WIDESPREAD RISK OF SHRA/TSRA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...MW
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
650 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SAT JUL 20 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW
FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING
CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT
WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON.
THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS
ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID
CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS
OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY
TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE
THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING
SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA.
DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER
VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE
DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST
AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT.
TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF
THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB
TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z.
SYNOPTIC OVERVIEW...
A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD.
MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING
AND RIDING THROUGH THE NORTHWEST FLOW.
TODAY...
ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH
DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS
SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON.
CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS
MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE
WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A
LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST
SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS
TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE
POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS
TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH
RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE
MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A
VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM.
925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN
THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID
80S.
TONIGHT...
CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD
DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS
BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING
A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO
NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO
IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL
NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT
INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION
WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD
FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT.
HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH
850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME
SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER
HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE
TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE
THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING
THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF
PRECIPITATION IN THE 20-40 RANGE OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM CDT SAT JUL 20 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW
PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY
AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT
EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP
INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE
RIDGE FROM BUILDING UP INTO THE FORECAST AREA.
SUNDAY INTO MONDAY NIGHT...
THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO
TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE
SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING.
HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH
OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO
PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE
AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP
FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS
FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY
NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST
SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE
CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID
LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING.
20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY.
ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM
SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED
COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE
IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE
IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS
WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS.
925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS
HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE
THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH:
1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE
MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA.
2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF
THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT.
3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT
BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH.
GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE
40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE
QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST
HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR
VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS.
CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH.
TUESDAY THROUGH FRIDAY NIGHT...
DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY...
WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE
FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD
AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF
CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY
NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA
DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION
OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO
SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE
HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY.
850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE
MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A
STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND
HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS
VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A
MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO
SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE
MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE.
ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH
PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR
NEXT WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 650 AM CDT SAT JUL 20 2013
VFR CONDITIONS EXPECTED AT THE TAF SITES TODAY ALONG WITH THE
POSSIBILITY OF SCATTERED THUNDERSTORMS DURING THE AFTERNOON AND
EARLY EVENING HOURS. A WEAK TROUGH WILL SAG SOUTH OUT OF NORTHERN
WISCONSIN TODAY AND POSSIBLY GENERATE SCATTERED THUNDERSTORMS THIS
AFTERNOON AS IT DRIFTS SOUTH THROUGH SOUTHEAST MINNESOTA AND
SOUTHWEST WISCONSIN. IF STORMS DEVELOP...THEY MAY PRODUCE GUSTY
WINDS AND SMALL HAIL. OTHERWISE PLAN ON A SCATTERED TO BROKEN
CEILINGS AT THE TAF SITES TODAY...WITH CLOUDS INCREASING DURING
THE AFTERNOON HOURS WITH CLOUD BASES IN THE 5 TO 8 KFT RANGE. SHOWERS
AND THUNDERSTORMS ARE POSSIBLE AGAIN LATE TONIGHT INTO SUNDAY
MORNING AS AN UPPER LEVEL TROUGH MOVES THROUGH THE AREA. THE BULK
OF THE ACTIVITY SHOULD OCCUR AFTER 12Z...WITH THE HIGHEST CHANCES
FOR SHOWERS AND STORMS SUNDAY AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
317 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SAT JUL 20 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW
FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING
CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT
WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON.
THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS
ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID
CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS
OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY
TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE
THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING
SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA.
DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER
VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE
DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST
AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT.
TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF
THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB
TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z.
SYNOPTIC OVERVIEW...
A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD.
MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING
AND RIDING THROUGH THE NORTHWEST FLOW.
TODAY...
ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH
DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS
SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON.
CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS
MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE
WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A
LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST
SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS
TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE
POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS
TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH
RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE
MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A
VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM.
925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN
THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID
80S.
TONIGHT...
CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD
DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS
BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING
A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO
NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO
IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL
NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT
INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION
WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD
FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT.
HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH
850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME
SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER
HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE
TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE
THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING
THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF
PRECIPITATION IN THE 20-40 RANGE OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM CDT SAT JUL 20 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW
PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY
AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT
EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP
INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE
RIDGE FROM BUILDING UP INTO THE FORECAST AREA.
SUNDAY INTO MONDAY NIGHT...
THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO
TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE
SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING.
HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH
OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO
PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE
AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP
FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS
FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY
NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST
SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE
CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID
LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING.
20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY.
ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM
SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED
COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE
IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE
IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS
WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS.
925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS
HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE
THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH:
1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE
MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA.
2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF
THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT.
3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT
BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH.
GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE
40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE
QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST
HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR
VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS.
CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH.
TUESDAY THROUGH FRIDAY NIGHT...
DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY...
WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE
FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD
AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF
CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY
NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA
DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION
OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO
SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE
HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY.
850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE
MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A
STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND
HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS
VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A
MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO
SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE
MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE.
ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH
PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR
NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1050 PM CDT FRI JUL 19 2013
SOME UPPER LEVEL FORCING...COUPLED WITH A BIT OF LOW LEVEL MOISTURE
CONVERGENCE/INSTABILTY...WAS SPARKING A SMALL AREA OF SHRA/TS OVER
CENTRAL MN. IT LOOKS LIKE THIS WILL HOLD TOGETHER FOR THE OVERNIGHT
HOURS...WORKING INTO WESTERN WI. BELIEVE THE PCPN WILL STAY NORTH OF
THE TAF SITES AT THIS MOMENT...SO WILL LEAVE ANY MENTION OUT OF THE
FORECAST.
GENERALLY VFR THOUGH THE DAY...BUT CLOUDS WILL BE ON THE INCREASE
FROM THE WEST THANKS TO ANOTHER UPPER LEVEL FEATURE. SOME SHRA/TS
ARE ALSO POSSIBLE...WHICH COULD IMPACT KRST. COVERAGE COULD BE MORE
SCATTERED THOUGH...AND CONFIDENCE ISN/T HIGH ENOUGH TO ADD SHRA OR
VCSH YET. SOMETHING TO MONITOR. CLOUDS WILL CONTINUE TO INCREASE AND
THICKEN FROM THE WEST SAT NIGHT...BUT LOOKS TO STAY VFR. RAIN
CHANCES WILL INCREASE FOR SUN/MON THANKS TO A FEW DIFFERENT WEATHER
TRIGGERS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1144 AM MDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1041 AM MDT SAT JUL 20 2013
SOME SHOWERS AND THUNDERSTORMS CONTINUE AS OF 16Z OVER THE
NORTHERN PANHANDLE. THE ACTIVITY HAS BEEN MOVING SOUTHEAST AND
SLOWLY DECREASING IN COVERAGE AND INTENSITY. FORECAST FOR THE
AFTERNOON AND EVENING LOOKS TO BE ON TRACK WITH STRONG STORMS
MAINLY EAST OF THE LARAMIE RANGE AND WARMER TEMPERATURES. A
SURFACE BOUNDARY HAS MOVED ACROSS THE CWA TO THE EAST OF THE
LARAMIE RANGE AND WAS POSSIBLY PUSHED SOUTH FROM OUTFLOW FROM
THE ACTIVITY OVER THE NORTH PART OF THE CWA. THE BOUNDARY LOOKS
TO END UP ALONG THE LARAMIE RANGE AND SHOULD PROVIDE THE FOCUS
FOR STORM DEVELOPMENT BY EARLY IN THE AFTERNOON. AS THE STORMS
MOVE OFF THE LARAMIE RANGE...THE ENVIRONMENT WILL BE MOIST AND
UNSTABLE. PRECIPITABLE WATER VALUES WILL BE AROUND AN INCH AND
THE 250MB JET JUST TO THE NORTH OF THE CWA WILL BE PRESENT.
THIS SITUATION IS DIFFERENT THAN IN RECENT WEEKS AND PERHAPS
MORE SIMILAR TO EARLY SUMMER WITH BETTER 0-6KM SHEAR ALLOWING
FOR SUPERCELL DEVELOPMENT. THE STORMS WILL PRODUCE HEAVY RAIN...
HAIL...STRONG WIND GUSTS AND FREQUENT LIGHTNING. SEVERE WEATHER
WILL BE POSSIBLE OVER THE PANHANDLE WITH LARGER HAIL AND WIND
GUST TO 60 MPH. THE HEAVY RAIN WILL CREATE LOCAL AREAS OF
FLOODING. CONSIDERED A FLASH FLOOD WATCH...BUT WILL WAIT UNTIL
AT LEAST STORMS START DEVELOPING. THE STORMS SHOULD BE MOVING
OVER THE SOUTHEAST WYOMING PLAINS EARLY IN THE AFTERNOON AND
BE EAST OF THAT AREA BY LATE AFTERNOON OR EARLY EVENING. THE
ACTIVITY WILL CONTINUE THROUGH AT LEAST THE L;ATE EVENING OVER
THE PANHANDLE.
IN A RECENT UPDATE...BUMPED UP POPS SOME OVER THE EASTERN CWA
AND ADDED THE MENTION OF HEAVY RAIN AND SMALL HAIL OVER THE
SOUTHEAST WYOMING PLAINS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1144 AM MDT SAT JUL 20 2013
MAIN AVIATION IMPACT WILL BE THE THREAT FOR SHOWERS AND
THUNDERSTORMS AND RESULTANT MVFR VSBYS THIS AFTERNOON AND
EVENING. THIS WILL ESPECIALLY BE THE CASE FOR TERMINALS TO THE
EAST OF THE LARAMIE RANGE WHERE THE ATMOSPHERE WILL BE MOST
FAVORABLE. AS OF 1745Z...CONVECTION HAS JUST BEGAN TO DEVELOP OFF
THE SOUTHEAST WYOMING MOUNTAINS. THIS TREND WILL CONTINUE AS
THUNDERSTORMS BECOME MORE NUMEROUS THIS AFTERNOON. THESE
THUNDERSTORMS ARE NOT ANTICIPATED TO AFFECT AIRFIELDS UNTIL AFTER
20Z OR 21Z. COVERAGE WILL BE SUFFICIENT ENOUGH TO INCLUDE A TEMPO
GROUP AT MOST SITES. SHOWERS AND THUNDERSTORMS WILL LIKELY PUSH
SOUTH AND EAST OF THE AIRFIELDS BY 02Z OR 03Z...WITH GRADUAL
IMPROVEMENT ANTICIPATED THEREAFTER. A FEW OF THE STRONGEST
THUNDERSTORMS MAY CONTAIN LARGE HAIL AND DAMAGING WINDS...
ESPECIALLY AT WESTERN NEBRASKA PANHANDLE SITES.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...HAHN
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1041 AM MDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1041 AM MDT SAT JUL 20 2013
SOME SHOWERS AND THUNDERSTORMS CONRINUE AS OF 16Z OVER THE
NORTHERN PANHANDLE. THE ACTIVITY HAS BEEN MOVING SOUTHEAST AND
SLOWLY DECREASING IN COVERAGE AND INTENSITY. FORECAST FOR THE
AFTERNOON AND EVENING LOOKS TO BE ON TRACK WITH STRONG STORMS
MAINLY EAST OF THE LARAMIE RANGE AND WARMER TEMPERATURES. A
SURFACE BOUNDARY HAS MOVED ACROSS THE CWA TO THE EAST OF THE
LARAMIE RANGE AND WAS POSSIBLY PUSHED SOUTH FROM OUTFLOW FROM
THE ACTIVITY OVER THE NORTH PART OF THE CWA. THE BOUNDARY LOOKS
TO END UP ALONG THE LARAMIE RANGE AND SHOULD PROVIDE THE FOCUS
FOR STORM DEVELOPMENT BY EARLY IN THE AFTERNOON. AS THE STORMS
MOVE OFF THE LARAMIE RANGE...THE ENVIRONMENT WILL BE MOIST AND
UNSTABLE. PRECIPITABLE WATER VALUES WILL BE AROUND AN INCH AND
THE 250MB JET JUST TO THE NORTH OF THE CWA WILL BE PRESENT.
THIS SITUATION IS DIFFERENT THAN IN RECENT WEEKS AND PERHAPS
MORE SIMILAR TO EARLY SUMMER WITH BETTER 0-6KM SHEAR ALLOWING
FOR SUPERCELL DEVELOPMENT. THE STORMS WILL PRODUCE HEAVY RAIN...
HAIL...STRONG WIND GUSTS AND FREQUENT LIGHTNING. SEVERE WEATHER
WILL BE POSSIBLE OVER THE PANHANDLE WITH LARGER HAIL AND WIND
GUST TO 60 MPH. THE HEAVY RAIN WILL CREATE LOCAL AREAS OF
FLOODING. CONSIDERED A FLASH FLOOD WATCH...BUT WILL WAIT UNTIL
AT LEAST STORMS START DEVELOPING. THE STORMS SHOULD BE MOVING
OVER THE SOUTHEAST WYOMING PLAINS EARLY IN THE AFTERNOON AND
BE EAST OF THAT AREA BY LATE AFTERNOON OR EARLY EVENING. THE
ACTIVITY WILL CONTINUE THROUGH AT LEAST THE L;ATE EVENING OVER
THE PANHANDLE.
IN A RECENT UPDATE...BUMPED UP POPS SOME OVER THE EASTERN CWA
AND ADDED THE MENTION OF HEAVY RAIN AND SMALL HAIL OVER THE
SOUTHEAST WYOMING PLAINS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAF ISSUANCE)
VFR CONDITIONS WILL PREVAIL THIS MORNING THROUGH 18Z. SURFACE WINDS
WILL BE VARIABLE AT 10 KT OR LESS WITH CLEAR SKIES. THERE IS A
BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS
INTO WESTERN NEBRASKA THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE. STRONG GUSTY WINDS...FREQUENT LIGHTNING...AND SMALL HAIL WILL
BE THE MAIN CONCERNS WITH THESE THUNDERSTORMS THROUGH THIS EVENING.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
552 AM MDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAF ISSUANCE)
VFR CONDITIONS WILL PREVAIL THIS MORNING THROUGH 18Z. SURFACE WINDS
WILL BE VARIABLE AT 10 KT OR LESS WITH CLEAR SKIES. THERE IS A
BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS
INTO WESTERN NEBRASKA THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE. STRONG GUSTY WINDS...FREQUENT LIGHTNING...AND SMALL HAIL WILL
BE THE MAIN CONCERNS WITH THESE THUNDERSTORMS THROUGH THIS EVENING.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
252 AM MDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1150 PM MDT FRI JUL 19 2013
VFR CONDITIONS WILL PREVAIL TONIGHT THROUGH 18Z SATURDAY. SURFACE
WINDS WILL BE VARIABLE 10 KT OR LESS WITH CLEAR SKIES. THERE IS A
BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS
INTO WESTERN NEBRASKA SATURDAY AFTERNOON. ADDED VCTS TO THE FORECAST
FOR NOW SINCE TIMING OF THESE THUNDERSTORMS IS RATHER UNCERTAIN
TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1110 PM MDT SUN JUL 21 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 304 PM MDT SUN JUL 21 2013
DRIER AIR MASS HAS SPREAD OVER THE NORTHERN AND WESTERN PORTIONS OF
THE AREA THIS AFTERNOON...DROPPING DEW POINTS INTO THE 20S OVER THE
CENTRAL MOUNTAINS AND ACROSS TELLER COUNTY. LOW LEVEL MOISTURE STILL
LURKS ON THE PLAINS...WHERE DEWPOINTS IN THE 50S HAVE LED TO CAPES
IN EXCESS OF 2K J/KG EAST OF I-25. VERY LITTLE IN THE WAY OF
FORCING/UPWARD MOTION THIS AFTERNOON...WITH ONLY VERY SPARSE
MOUNTAIN CONVECTION MAINLY SOUTH OF HIGHWAY 50. HAVE ALSO SEEN A
COUPLE CELLS DEVELOP THEN DISSIPATE QUICKLY OVER EASTERN EL PASO
COUNTY...WHERE MOISTURE GRADIENT IS FAIRLY TIGHT AND RESIDUAL
BOUNDARY FROM LAST NIGHT`S CONVECTION REMAINS. LATEST HRRR HINTS AT
TSRA DEVELOPING EAST OF I-25 THIS EVENING....AND WHILE FORCING IS
WEAK...LARGE CAPES ARE HARD TO IGNORE...AND WILL THROW IN SOME LOW
POPS FOR THE PLAINS EARLY THIS EVENING. STILL EXPECT ANY STORMS TO
DISSIPATE QUICKLY AFTER SUNSET. ON MONDAY...AIR MASS CONTINUES TO
DRY...AND EVEN THE MOUNTAINS WILL BE HARD PRESSED TO SEE MORE THAN
SOME MODERATE CUMULUS BUILD-UP IN THE AFTERNOON. KEPT SOME VERY LOW
POPS IN PLACE OVER THE HIGHER PEAKS...BUT EVEN THESE MAY BE
OVERDONE. RISING HEIGHTS AND MID-LEVEL TEMPS SUGGEST A HOT DAY IS IN
STORE...AS READINGS ON THE PLAINS REACH 100F...WITH 80/90S
ELSEWHERE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 304 PM MDT SUN JUL 21 2013
THE ENTIRE EXTENDED FORECAST PERIOD CAN BE SUMMED UP IN TWO
SENTENCES. AN UPPER RIDGE OF HIGH PRESSURE WILL REMAIN LOCKED INTO
PLACE ACROSS THE REGION. MINOR DISTURBANCES IN THE FLOW ALOFT
ROTATING AROUND THE RIDGE WILL KICK OFF ENHANCED CONVECTION TOWARDS
THE LATTER HALF OF THE WEEK. NOW FOR THE SPECIFICS...
MONDAY NIGHT THROUGH TUESDAY...EC...GFS AND EVEN THE NAM MODEL ARE
NOW INDICATING THAT IT SHOULD REMAIN FAIRLY DRY THROUGH MUCH OF
TUE...WITH ISOLATED TO LOW END SCATTERED POPS OVER THE HIGHER
TERRAIN. A COLD FRONT DROPS DOWN TO THE PALMER DVD ON TUE...BUT THE
LATEST RUNS INDICATE IT DOES NOT DROP SOUTH UNTIL LATE TUE...SETTING
THE STAGE FOR WED. LOOK FOR MAX TEMPS ACROSS THE E PLAINS TO BE
AROUND 100 DEG F ON TUE...AND IN THE MID TO UPPER 80S FOR THE HIGH
VALLEYS.
WEDNESDAY THROUGH FRIDAY...THE COLD FRONT WILL DROP SOUTH ACROSS THE
CWA LATE TUE...WITH WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY
EXPECTED FOR A MAJORITY OF THE FORECAST AREA BOTH WED AND THU. MAX
TEMPS ARE EXPECTED TO BE ABOUT 10 DEGREES COOLER WITH SCATTERED POPS
ALL AREAS BORDERING ON LIKELY. WED AFTN THROUGH THU AFTN LOOKS LIKE
IT WILL BE THE MOST PROBABLY TIME FRAME FOR FLASH FLOOD POTENTIAL
ACROSS AREA BURN SCARS. BY FRIDAY THE UPPER RIDGE AXIS STARTS TO
SHIFT SLIGHTLY TO THE EAST AS THE RIDGE AMPLIFIES...AND THOUGH THERE
IS STILL A GOOD CHANCE FOR CONVECTION FOR ALL AREAS...IT WILL BE DUE
TO A REINFORCED MONSOON PLUME AS OPPOSED TO FRONTAL/LLVL FORCING.
TEMPS ON FRI WILL BE AS COOL OR PERHAPS EVEN A COUPLE OF DEGREES
COOLER.
SATURDAY AND SUNDAY...EXTENDED MODELS ARE POINTING TO ANOTHER
STRONGER DISTURBANCE MOVING ACROSS THE DAKOTAS AND MIDWEST ON
SAT...PUSHING ANOTHER COLD SURGE INTO EASTERN CO LATE SAT INTO SUN.
WHEREAS SAT IS FORECAST TO HAVE DIURNAL CONVECTIVE ACTIVITY TIED
MAINLY TO THE HIGHER TERRAIN...SUNDAY COULD BE ANOTHER ACTIVE DAY
WITH WIDESPREAD CONVECTION AND SLIGHTLY COOLER TEMPS. MOORE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1110 PM MDT SUN JUL 21 2013
UPPER HIGH EXPECTED TO AMPLIFY ACROSS THE GREAT BASIN DRIER
WITHIN THE WEAK NORTHERLY FLOW ALOFT PUSHING MONSOONAL MOISTURE
PLUME SOUTH AND WEST OF THE AREA THROUGH THE DAY TOMORROW. THIS
WILL KEEP VFR CONDTIONS IN PLACE AT TAF SITES WITH ISOLATED MAINLY
HIGH BASED CONVECTION EXPECTED TO STAY OVER AND NEAR THE HIGHER
TERRAIN.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
356 AM EDT Mon Jul 22 2013
.NEAR TERM [Through Today]...
The large scale longwave pattern is highlighted by weak ridging
over Wrn Conus and a broad upper level trough across much of the
Cntrl and Ern U.S. Several shortwaves were noted in water vapor
imagery moving across base of trough including one over NW AL. At
the surface, a ridge of high pressure extends from the Atlc WWD
across the FL Peninsula and Cntrl Gulf of Mexico. A weak and
dissipating trough was noted across the WRN forecast area. 24hr
temp/dew point comparisons indicate little change in airmass last
24 hrs. Latest radar pix shows less convection than forecast
developing over the Gulf waters. Still, HRRR and WRF show marine
convection moving onshore after 10z from Panhandle waters reaching
FL/AL border by 14z. Have updated 06z-12z Grids to lower POPS and
will monitor in case another update is needed.
During the rest of today, progressive WSW steering flow as
unseasonably amplified upper trough digs SEWD into TN Valley and
deepens increasing tropical moisture plume, aided by AL shortwave
moving ESE provides additional lift. Surface ridge remains to our
S locally yielding SW flow. PWATs across the region from JAX west
to Dothan and beyond in excess of 2 inches this aftn. This will
combine with seabreeze/mesoscale outflows clashes from leftover
boundaries from surface trough for sct/numerous showers and
thunderstorms later today. As reflected in CAM and other models,
highest POPs over the NW zones closest to the upper energy. Will
go with 40-80% SE-NW POP gradient. RAP13 soundings show uni-
directional very moist profiles which favor good rain producers
and given recent rains, aggravate chances of at least nuisance
flooding again today. CAM QPF/flood tools shows Panhandle as best
bet with 1-2 inches avg STP. Although Shear unimpressive, model
aftn CAPE around 2400 J/KG across SE AL. Add presence of shortwave
plus any boundary clashes this favors at least strong storms to
isold severe storms with best bet SE AL/ adjacent GA/FL 21z-00z.
This, along with max temps will be partly dependent on amount of
morning cloudiness and where drier air sets making max temp
forecast a little tricky. Inland Highs generally 88 to 90.
&&
.SHORT TERM [Tonight through Wednesday]...
The pattern will transition to more of a northwest flow aloft
through the short term as the upper level trough axis moves east
of the area. A series of shortwaves is expected to move through
the base of the trough and aid in convective development over the
forecast area (PoPs 40-60% during the day). The northwest flow
aloft will also aid in advecting steeper than normal mid-level
lapse rates into the area by Tuesday into Wednesday, which may
increase the threat of isolated, pulse severe storms. These would
be most likely over the northern and western portions of the area.
The 22/00z GFS forecasts 700-500 mb lapse rates between 6-7 C/km,
which is 1-1.5 C/km above climo for this time of year.
&&
.LONG TERM [Wednesday Night through Sunday]...
The upper flow across the CONUS will be dominated by an eastern
trough and western ridge. Through most of the extended period, the
upper trough axis is forecast to be just east of the CWA, with
northwest flow aloft. While this flow is typically drier across
the region, the presence of a nearly stationary trough across the
northern half of the area will offset this to some extent. With
this in mind, will generally keep the PoPs at or below 50 percent
through the extended, especially for Thursday into the weekend.
With the slightly lower rain chances than the past several days,
expect high temperatures to creep back into the lower to mid 90s
as well.
&&
.AVIATION...
[Through 06z Tuesday] Although locales remain VFR at 07z, HRRR
show showers and thunderstorms developing at our western
terminals aft 09z and spreading E/NE reaching the FL/AL border
thru 14z. Therefore decided to include MVFR CIGS/VSBYS 09Z-14z
except possibly at ECP with brief IFR/LIFR CIGs possible until
around sunrise. After morning showers and thunderstorms diminish,
there will likely be a break, and then another round in the
afternoon with conditions very similar to what we saw on Sun with
MVFR CIGS/VSBYS and gusty winds in any heavy rain or strong
storms.
&&
.MARINE...
With a persistent trough to the north and high pressure to the
south, winds over the marine area will be primarily out of the
southwest to west-southwest this week between 10 and 15 knots.
&&
.FIRE WEATHER...
Red flag conditions are not expected for the next several days.
&&
.HYDROLOGY...
A few rivers still remain at or near flood stage, including the
Aucilla and Econfina rivers. The Steinhatchee river is also out of
its banks south of US 19 with minor flooding expected downstream
of the gage for the next day or two. Scattered showers and storms
are expected through much of this week, but should not be
sufficient to produce widespread flooding. However, localized
areas of heavy rain are likely and could cause some urban and
small stream flooding on occasion.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 89 74 92 74 93 / 60 50 60 50 50
Panama City 86 76 88 76 88 / 60 50 60 40 50
Dothan 88 73 92 73 91 / 70 40 60 50 50
Albany 89 73 92 74 92 / 70 40 60 40 50
Valdosta 89 73 92 74 94 / 70 40 60 40 50
Cross City 89 73 88 73 90 / 50 40 60 40 50
Apalachicola 86 77 88 77 90 / 60 50 60 40 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Risk for Rip Currents for FLZ108-112-114.
GA...None.
AL...None.
GM...None.
&&
$$
Near Term/Aviation/Fire Wx...Block
Short Term/Marine/Hydrology...DVD
Long Term...Camp
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1150 PM CDT SUN JUL 21 2013
.DISCUSSION...
ISSUED 850 PM CDT SUN JUL 21 2013
UPDATED THE FORECAST TONIGHT TO INCREASE CHANCES OF SHOWERS ALONG
WITH A FEW THUNDERSTORMS. ALSO NUDGED UP LOW TEMPERATURES A DEGREE
OR TWO TO AROUND 70F...DUE TO MOIST DEWPOINTS CURRENTLY IN THE LOW
TO MID 70S. A FEW POCKETS OF LOCALLY HEAVY RAINS OF 1.5 TO 3 INCHES
ALSO TO OCCUR TONIGHT ESPECIALLY FROM I-72 SOUTH...AS JACKSONVILLE
HAS EXPERIENCED SINCE 5 PM.
THE HRRR MODEL HAS BEEN HANDLING THIS WEATHER SYSTEM THE BEST SO
FAR SO LEANED ON THIS MODEL FOR TONIGHT`S FORECAST. SHOWERS AND A
FEW THUNDERSTORMS TO SPREAD INTO EASTCENTRAL IL NEXT NEW HOURS...
THEN DIMINISH FROM WEST TO EAST LATE THIS EVENING AND OVERNIGHT.
A SHORT WAVE MOVING INTO CENTRAL IL THIS EVENING AND EXITING SE OF
AREA MONDAY MORNING WILL KEEP LIKELY CHANCES OF SHOWERS AND FEW
THUNDERSTORMS PAST SUNDOWN TONIGHT AND LIKELY CHANCES CONTINUE OVER
EASTERN IL OVERNIGHT...WHILE DIMINISHING TO SLIGHT CHANCE IN THE WEST.
A QUASI STATIIONARY FRONTAL BOUNDARY OVER NE PARTS OF IA/IL AND
INTO CENTRAL INDIANA WILL GRADUALLY WEAKEN THROUGH MONDAY...WITH
CENTRAL/SE IL STAYING ON THE SOUTH SIDE (MILD/MOIST SIDE) OF THE
BOUNDARY. TEMPS CURRENTLY IN THE 70S TO ONLY SLIP TOWARD 70F FOR
LOWS OVERNIGHT WHICH JACKSONVILLE IS CURRENTLY DOWN TO WITH HEAVY
RAINS PAST FEW HOURS FROM THUNDERSTORMS. EXPECT LIGHT SSE TO
VARIABLE WINDS TONIGHT WITH SOME FOG POSSIBLE OVERNIGHT INTO MID
MORNING MONDAY WITH VSBYS DOWN TO 1-3 MILES.
07
&&
.AVIATION...
ISSUED 1150 PM CDT SUN JUL 21 2013
IFR TO MVFR VSBYS AND CEILINGS POSSIBLE WITH SHOWERS AND A FEW
THUNDERSTORMS WITH LOCALLY HEAVY RAINS THE NEXT FEW HOURS AT DEC
AND CMI WHILE A FEW LIGHT SHOWERS COULD BRING MVFR CONDITIONS TIL
08Z ALONG I-55 AT BMI AND SPI. CONVECTION TIED TO A SHORT WAVE
THAT IT OVER CENTRAL IL AND TO EXIT SOUTHEAST OF AREA BY DAWN.
HAVE 1-3 MILES WITH FOG DEVELOPING DURING OVERNIGHT UNTIL 14-15Z
MONDAY. CLEARING SKIES WORKING EASTWARD FROM MO INTO WEST CENTRAL
IL AROUND QUINCY LATE THIS EVENING. IF CLEARING SKIES TO GET INTO
WESTERN TAF SITES OF PIA AND SPI AFTER 08Z WHERE FOG COULD BECOME
MORE WIDESPREAD WITH PATCHY DENSE FOG EVEN POSSIBLE...THOUGH DID
NOT CARRY VSBYS THAT LOW DUE TO UNCERTAINTY OF CLEARING ESPECIALLY
OVER EASTERN TAF SITES. ANY LINGERING LOW CLOUDS AND FOG SHOULD
LIFT AFTER 14-15Z MONDAY MORNING WITH BROKEN MVFR CEILINGS
LINGERING LONGEST AT CMI POSSIBLY INTO MIDDAY. FAIR WEATHER
EXPECTED MONDAY AFTERNOON/EVENING WITH COLD FRONT OVER THE
NORTHERN PLAINS NOT IMPACTING CENTRAL IL TAF SITES UNTIL LATER
MONDAY NIGHT INTO TUE. LIGHT AND VARIABLE WINDS OVERNIGHT TO
BECOME SW 4-7 KTS AFTER 15Z/MON AND LIGHT SSW BY SUNSET MON
EVENING.
07
&&
.PREV DISCUSSION...
ISSUED 239 PM CDT SUN JUL 21 2013
MAIN CONCERNS THIS PACKAGE WILL CONTINUE TO BE PCPN CHANCES FOR
THE SHORT TERM AND THEN PCPN CHANCES AGAIN AT THE END OF THE WEEK
AND INTO THE WEEKEND...IN THE LONG TERM PERIOD.
MODELS SHOW GOOD AGREEMENT WITH KEEPING THE MID LEVEL NORTHWEST
FLOW IN PLACE...WITH A RIDGE BUILDING OUT OVER THE ROCKIE MOUNTAIN
REGION...ALL THROUGH MID WEEK. THE NORTHWEST FLOW WILL ALSO
CONTINUE INTO THE EXTENDED PERIOD AND MODELS LOOK OK HERE TOO
UNTIL LATE IN THE WEEK AND THE WEEKEND. ECMWF APPEARS TO BE
STRONGER WITH A MID LEVEL SYSTEM COMING DOWN INTO THE AREA DURING
THE END OF THE PERIOD.
SHORT TERM...TONIGHT THROUGH WEDNESDAY
FRONTAL SYSTEM OVER THE AREA THIS AFTERNOON WILL GRADUALLY WASHOUT
TONIGHT THROUGH TOMORROW AS A STRONGER WEATHER SYSTEM DEVELOPS OUT
IN THE PLAINS. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS
THE ENTIRE CWA THIS EVENING AND THEN IN THE EAST AFTER
MIDNIGHT...WITH CHANCES BACK TO THE WEST. LIGHT SHOWERS ARE
ONGOING BUT REMNANTS OF AN MCS IN IOWA HAVE CONTINUED TO GET
STRONGER IN SOUTH CENTRAL IOWA AND WILL MOVE EAST-SOUTHEAST INTO
THE CWA THIS EVENING AND THROUGH TONIGHT. BELIEVE THIS
LINE/COMPLEX OF STORMS WILL FOLLOW THE STATIONARY BOUNDARY OVER
THE AREA AS IT MOVES EAST-SOUTHEAST. VARIOUS SHORT TERM MODELS
FORECAST THIS AREA OF STORMS EAST AND SOUTHEAST INTO CENTRAL
ILLINOIS THIS EVENING...THEREFORE CONFIDENCE IS HIGH ENOUGH FOR
LIKELY POPS. NO SEVERE IS EXPECTED WITH THESE STORMS...BUT LOCALLY
HEAVY RAINFALL AND DEADLY LIGHTNING WILL BE LIKELY. PCPN WILL
DIMINISH TOMORROW...BUT WITH LOTS OF LOW LEVEL MOISTURE AND A
STATIONARY BOUNDARY IN THE AREA...CANT RULE OUT A CHANCE OF
THUNDERSTORMS SOMEWHERE TOMORROW. PCPN CHANCES WILL CONTINUE AND
INCREASE INTO TOMORROW NIGHT AND TUESDAY AS ANOTHER...STRONGER
FRONT PUSHES INTO AND THROUGH THE AREA. FORECAST FOR THIS FRONT
APPEAR TO BE THAT IT WILL PUSH SHOULD OF THE STATE LATE TUE NIGHT
AND THEN BRING DRIER AND LESS HUMID AIR INTO THE REGION FOR
WEDNESDAY.
APPEARS TEMPS WILL BE QUITE WARM ONE MORE DAY TOMORROW. THEN
ADDITIONAL CLOUD COVER AND PCPN WILL CAUSE TEMPS TO BE SLIGHTLY
COOLER FOR TUESDAY. MUCH COOLER TEMPS ARE THEN EXPECTED AFTER THE
FRONT MOVES THROUGH THE AREA FOR WEDNESDAY.
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
DRY WEATHER WILL CONTINUE THROUGH THUR NIGHT AS NORTHWEST FLOW
WILL CONTINUE ACROSS THE AREA. A STRONGER SYSTEM/SHORT WAVE TROUGH
WILL THEN DEVELOP AND MOVE TOWARD THE AREA FOR LATE IN THE WEEK.
ECMWF IS STRONGER AND LOOKS MORE CONSISTENT FROM PREVIOUS RUNS WITH
THIS NEXT SYSTEM...THAN THE GFS. LEANING TOWARD THE ECMWF MODEL
GIVES A FORECAST OF PCPN CHANCES FOR FRIDAY THROUGH SATURDAY
NIGHT...SOMEWHERE IN THE CWA...THEN DRY WEATHER POSSIBLE SUNDAY.
STILL LOTS OF UNCERTAINTY WITH THIS PERIOD OF THE FORECAST SO
WOULD NOT BE SURPRISED TO SEE CHANGES TO IT OVER THE NEXT SEVERAL
DAYS.
TEMPS SHOULD BE COOLER THAN LAST WEEK GIVEN THE NORTHWEST FLOW AND
WENT COOLER THAN GUIDANCE FOR SAT AND SUNDAY.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
318 AM EDT MON JUL 22 2013
.SHORT TERM (Today through Tuesday)...
Issued at 315 AM EDT Sun Jul 21 2013
Pronounced shortwave trough, centered now along the northern MO/IL
border will move into our region today. Combined with a tropical
airmass in place, and we should see another round of showers and
storms this morning into the afternoon. Seeing one line of storms
forming over the MO/AR border into western KY and another one closer
to a stationary front to our north, along the central IL/IN border.
With additional storms in the forecast, have decided to lift a flash
flood watch for a portion of our forecast area. The Bluegrass has
the lowest flash flood guidance, with 3-hour guidance between 1.5
and 2 inches. Areal average QPF for that region is around an inch,
but it easily could be higher with any slow-moving heavy storms.
Airmass looks too tropical for severe weather, though we do look to
have a weak low moving up the Ohio Valley ahead of the upper level
feature, so will have to watch for some rotation in any storms that
form.
We should see a break in the precip tonight, but the airmass does
not dry out until after this period, so cannot rule out additional
isolated storms. Another wave looks to come across the area Tuesday,
bringing enhanced rain chances once more. Coverage should be more
limited than today, but soundings favor a better chance for stronger
storms, with gusty winds and hail as the main threats.
Temperatures today will depend on how quick the precip exits our
region this afternoon. Have gone with higher values over the west,
mid 80s compared with around 80 for the east. Temperatures tonight
should be similar to this morning, with no real change in airmass.
Readings should warm back into the upper 80s for Tuesday.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 300 AM EDT Mon Jul 22 2013
Longwave 500mb upper air pattern early Wednesday will feature a
broad ridge centered over the Intermountain West and a robust trough
centered over the Great Lakes. Northwest flow will influence the
Lower Ohio Valley. Ultimately, this pattern will bring pleasant,
seasonably cool weather and relatively low dewpoints, especially for
the period Wednesday through Friday.
Several weak waves may move southeast across the Lower Ohio Valley
Tuesday through Saturday. The first will cross the Ohio River
Tuesday evening. High pressure over the upper midwest will build in
behind a cold front that will move across the Commonwealth during
the early morning hours Wednesday. Scattered convection will likely
end from the north to the south during the morning hours Wednesday
as drier air arrives from the northwest.
Think that Wednesday afternoon will stay dry with noticeably less
humid conditions. Northwesterly winds behind this front will lower
dewpoints into the upper 50s by Wednesday evening.
High pressure will build across the northern Ohio Valley Thursday
and continue through Friday. Expect mostly clear skies with
comfortable nights. Highs will stay in the mid 80s with lows well
down into the 60s. The proximity of the surface high to our north
will lead to light northeasterly to easterly winds through early
Saturday.
For several days now, long range guidance has advertised a quick
return of moisture ahead of an upper wave on Saturday. Showers and
storms may approach as early as Saturday morning and continue during
the day Saturday just ahead of a progressive 500mb trough.
Temperatures still will stay relatively mild Saturday and Sunday,
with highs in the 80s and upper 60s at night. Expect clearing Sunday
with dry conditions.
&&
.AVIATION (06Z TAF Update)...
Issued at 135 AM EDT Mon Jul 22 2013
Very moist atmosphere remains in place ahead of an upper level
disturbance forecast to move through the region this afternoon. Have
tried to time storms based on RAP forecasts for now, giving a brief
lull to the sites early than more storms. That same moisture likely
also will cause brief cig/vsby issues despite storm forecast. Rain
chances should become more limited when that trough comes through so
have kept in some VFR cigs by mid/late afternoon with no storms.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ036-037-041>043-
048-049-057.
$$
Short Term.......RJS
Long Term........JSD
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
201 AM EDT MON JUL 22 2013
.UPDATE...
ISSUED AT 200 AM EDT MON JUL 22 2013
INGESTED THE LATEST OBSERVATIONAL DATA INTO THE FORECAST GRIDS TO
ESTABLISH NEW TRENDS. OVERALL THE INHERITED FORECAST WAS IN GOOD
SHAPE...HOWEVER...WILL BE ISSUING A QUICK UPDATE TO REMOVE SOME
OUTDATED WORDING FROM THE ZONE FORECAST TEXT PRODUCT.
UPDATE ISSUED AT 932 PM EDT SUN JUL 21 2013
TRAINING STORMS WERE STILL ONGOING OVER THE NORTHERN SECTION OF THE
CWA AS WAS DISCUSSED IN THE PREVIOUS UPDATE. WENT AHEAD AND EXTENDED SCT
POPS FOR THE NEXT COUPLE OF HOURS...MAINLY ALONG THE MOUNTAIN PARKWAY
WHERE MAIN SHOWER ACTIVITY HAS BEEN LOCATED. LATEST RADAR TRENDS ARE
SHOWING BEST SHOWER ACTIVITY DIMINISHING...BUT LOW END CHANCE POPS
ARE STILL WARRANTED FOR ONGOING ACTIVITY AND POTENTIAL REDEVELOPMENT.
EXCESS MOISTURE ACROSS THE NORTH AND EAST HAS LED TO FOG DEVELOPMENT
AT THE NWS OFFICE. AS RAIN CONTINUES TO DIMINISH...EXPECT FOG TO
PREVAIL THROUGH MUCH OF THE NIGHT BEFORE NEXT AREA OF WIDESPREAD
SHOWERS AND THUNDERSTORMS MOVES IN BY EARLY MORNING. MADE THIS UPDATE
TO THE WEATHER GRIDS AS WELL...ADDING FOG IN FOR VALLEYS MAINLY IN
THE EASTERN CWA.
UPDATE ISSUED AT 544 PM EDT SUN JUL 21 2013
A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN
HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS
FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS
BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND
THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS.
ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY
BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT
FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS
WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 325 PM EDT SUN JUL 21 2013
MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT
THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS
PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH
THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN
KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET
MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE
APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS
IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC
FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW
MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST.
GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE
SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH
FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN
ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE
POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH
PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM
COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST
ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE
NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE
THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING
UP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 325 PM EDT SUN JUL 21 2013
THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL
TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED.
HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND
TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA
LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF
THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS
FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE
HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH
EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO
CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON
SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE
CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS
FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG.
IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM
SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A
DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL
PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF
SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND
UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS
WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL.
A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER
THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE
MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR
WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF
AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS
HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW
PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO
KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND
THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT
COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH
ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE
COOLER AIR REMAINS TO START THE NEW WORK WEEK.
THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN
THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM
THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF.
ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY
NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 200 AM EDT MON JUL 22 2013
CHALLENGING AVIATION FORECAST THIS TIME AROUND...WITH SEVERAL ISSUES
TO CONSIDER. FIRST WILL BE THE EXTENT OF FOG AROUND THE FORECAST...AS
WE ARE CURRENTLY EXPERIENCING A LULL IN SHOWER AND STORM ACTIVITY.
SKIES AT TAF ISSUANCE WERE PARTLY CLOUDY WITH VERY LIGHT WINDS...SO
SOME AREAS WILL BE EXPERIENCING FOG OVERNIGHT. JKL WILL BE THE MOST
CHALLENGING DUE TO THE ELEVATION OF THE AIRPORT. WILL LIKELY SEE WILD
FLUCTUATIONS IN CIGS AND VSBYS AT JKL UNTIL MORE WIDESPREAD SHOWERS
AND STORMS MOVE ACROSS THE AREA LATER THIS MORNING. HAVE USED A TEMPO
GROUP TO ADDRESS ANY POTENTIAL LIFR CONDITIONS...WITH IFR TO MVFR
CONDITIONS OTHERWISE. WENT A BIT MORE OPTIMISTIC WITH LOZ AND SME
GOING WITH MOSTLY MVFR CONDITIONS THROUGHOUT THE PERIOD. THE PERIOD
FROM 10Z ON WILL FEATURE WIDESPREAD SHOWERS AND STORMS WITH THE
POSSIBLILITY OF LOCALLY HEAVY RAINFALL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...AR
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...AR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
136 AM EDT MON JUL 22 2013
...Updated Aviation Discussion...
.FORECAST UPDATE...
Issued at 840 PM EDT Sun Jul 21 2013
Two effective boundaries are forcing convection this evening, as we
remain in a juicy environment ahead of an approaching upper impulse.
Isolated to scattered storms are firing along and just south of the
I-64 corridor, with one particularly vigorous cell that has produced
torrential rain and wind gusts near 50 mph in the Louisville Metro.
A more solid area of rain with a leading convective line has fired
along a northward-moving boundary in western Kentucky, and is trying
to spread into south central Kentucky.
May continue to see development near Interstate 64 into late
evening, especially as outflows interact with each other. Otherwise
the storms to our west will spread into the area, with likely POPs
looking like a good bet after midnight. Current zone forecast has
this
handled fairly well, but the point-and-click and matrices have been
updated to hone the finer details of when and where it will rain the
rest of this evening.
&&
.SHORT TERM (Tonight through Monday Night)...
Issued at 300 PM EDT Sun Jul 21 2013
The synoptic pattern this afternoon features a low-amplitude western
ridge/eastern trough pattern, placing the Ohio Valley within
northwest flow aloft. A rather potent shortwave trough (compared to
past weeks) will be the main focus for convection through the short
term period.
Convection this afternoon has remained across southern Kentucky and
Tennessee. In fact, a cold pool finally developed in the convection
across southern KY, which raced into Tennessee and has since cut off
much of the CWA from any thunderstorm activity. While a few
thunderstorms may redevelop across the area yet this afternoon into
the evening, think anything will remain rather isolated in the
near term.
The main focus of the period will come tonight into early Monday
morning, as the aforementioned shortwave trough dives into the
region. Guidance suggests quite a bit of moisture transport
occurring in response to the approaching PV anomaly. A low-level
jet, which has been absent as of late, will increase to 20-30 knots.
PWATs will rise into the 2-2.25 inch range overnight, which is in
the 99th percentile climatologically for this time of year.
Additionally, warm cloud depths will rise to near 14,000 feet.
Seriously considered going with a flash flood watch, but there are a
few mitigating factors. Slightly better tropospheric flow (500mb
wind speeds will increase to 20-30 knots) will favor quicker storm
motions than we`ve seen of late. Additionally, it`s tough to say
which mesoscale boundaries will focus convection, and whether the
orientation of any of these boundaries will favor training.
Therefore, after coordination with surrounding offices, will hold
off on one for now, but will advise the evening shift of the
situation. Despite better flow aloft, the highly saturated
atmospheric profiles will limit any severe potential due to a lack
of instability and dry air aiding in downdraft potential.
Therefore, expect the main threats to be torrential rain and
lightning.
The lead shortwave trough will push through by late Monday morning.
How the overnight convection plays out will largely factor into the
afternoon prospects for convection as the trough axis slides
through. Think that many areas will likely be worked over, so don`t
think coverage tomorrow afternoon into the evening will be all that
impressive. Nevertheless, as the trough axis swings through,
additional convection will likely develop, with the most favored
areas being east of Interstate 65.
Drier air and subsidence behind the wave should really diminish
coverage Monday night. Will carry only chance to slight chance
pops, which may still be too generous especially across southern
Indiana and northern KY, which have good prospects of staying dry.
Temperatures through the short term period will be highly dependent
on convection. Therefore, went with a general blend of guidance,
which puts lows tonight and tomorrow in the lower 70s, with highs
Monday in the middle 80s.
.LONG TERM (Tuesday through Sunday)...
Issued at 238 PM EDT Sun Jul 21 2013
A cool front will approach from the northwest Tuesday and move
through the region Tuesday night. The best mid and upper dynamics
will be along and west of the Wabash Valley Tuesday, but we could
still see some strong to locally severe storms Tuesday evening west
and northwest of Louisville. Also, PWATs are only slightly elevated
so widespread heavy rain isn`t expected but locally heavy downpours
will certainly be possible.
How fast the front moves through and how far it gets south of
Kentucky will determine our chances for convection on Wednesday. It
does appear that high pressure to our north will wait until
Wednesday night to really push in, so will go along with neighboring
offices and hold on to a small low confidence PoP on Wednesday,
especially south.
High pressure from the Great Lakes will be in control for the second
half of the work week, keeping us dry.
The models have been flaky regarding this weekend`s weather. The
general sense, though, is that some sort of storm system will be
coming in from the west giving a chance of showers and
thunderstorms.
We`ll have typical summer temperatures this week with highs in the
80s and lows in the 60s (a little warmer in urban Louisville).
&&
.AVIATION (06Z TAF Update)...
Issued at 135 AM EDT Mon Jul 22 2013
Very moist atmosphere remains in place ahead of an upper level
disturbance forecast to move through the region this afternoon. Have
tried to time storms based on RAP forecasts for now, giving a brief
lull to the sites early than more storms. That same moisture likely
also will cause brief cig/vsby issues despite storm forecast. Rain
chances should become more limited when that trough comes through so
have kept in some VFR cigs by mid/late afternoon with no storms.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RJS
Short Term.......KD
Long Term........13
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1233 AM CDT MON JUL 22 2013
.UPDATE...
ISSUED AT 1233 AM CDT MON JUL 22 2013
UPDATED AVIATION SECTION ONLY.
&&
UPDATE...
ISSUED AT 456 PM CDT SUN JUL 21 2013
AFTER LOOKING AT NEW HRRR MODEL REFLECTIVITY DATA AND 18Z NAM...IT
APPEARS HEAVY RAIN IS MORE LIKELY IN SW INDIANA...SE ILLINOIS...AND
NW KENTUCKY LATE TONIGHT INTO EARLY MONDAY. 850 MB LOW LEVEL FLOW IS
FORECAST TO STRENGTHEN TO AROUND 20 KNOTS...WITH STRONG INDICATIONS
OF A BACKBUILDING MCS. RAISED POPS FOR THE OVERNIGHT HOURS TO
CATEGORICAL OR LIKELY IN NE COUNTIES. THE ENSEMBLE MEANS OF THE SREF
AND GFS ALSO SHOW QPF BULLSEYES IN THAT AREA OVERNIGHT. SURFACE TO
850 MB CONVERGENCE AXIS IS FORECAST TO BE IN THAT AREA WITH A 500 MB
SHORTWAVE TROUGH JUST UPSTREAM.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 215 PM CDT SUN JUL 21 2013
MAIN FORECAST CONCERN TONIGHT IS HEAVY RAIN POTENTIAL. LOTS OF
MOISTURE AND INSTABILITY IS IN PLACE...ALONG WITH A BROAD AREA OF
WEAK LIFT. THE PRIMARY LIFTING MECHANISM IS A 500 MB SHORTWAVE
ADVANCING EAST/SOUTHEAST ACROSS CENTRAL MISSOURI. CONVECTION HAS
BEEN SLOWLY INCREASING THIS AFTERNOON ALONG AND SOUTH OF A WEAK WARM
FRONT THAT EXTENDS FROM THE LOWER OHIO VALLEY TO NORTHWEST
ARKANSAS.
THE STORMS WILL CONTINUE TO INCREASE THROUGH THE EARLY EVENING
HOURS...AIDED BY THE APPROACHING SHORTWAVE AND WARM FRONTAL
CONVERGENCE. WILL MENTION HEAVY RAIN IN GRIDS AND ZONES. LOW LEVEL
WIND SPEEDS ARE CURRENTLY A LITTLE LOWER THAN OPTIMUM FOR AN
ORGANIZED FLOODING THREAT. HOWEVER...RAP MODEL RUNS INDICATE SOME
INCREASE AND BACKING OF LOW LEVEL WINDS LATE TODAY AND THIS EVENING.
POTENTIAL FOR EXCESSIVE RAINFALL AND LOCAL FLOODING WILL NEED TO BE
MONITORED THROUGH EVENING.
LATER TONIGHT AND MONDAY MORNING...WEAKENING INSTABILITY AND
DECREASING UPPER SUPPORT SHOULD BRING A GRADUAL DECREASE IN COVERAGE
AND INTENSITY OF THE PRECIP. TEMPS ON MONDAY WILL DEPEND ON TIMING
OF PARTIAL CLEARING...WHICH SHOULD TAKE PLACE FROM WEST TO EAST AS
THE DAY GOES ON. WILL CONTINUE WITH PREVIOUS FORECASTS THAT ARE
CLOSER TO GFS MOS THAN THE COOLER NAM MOS. A RELATIVE LULL IN PRECIP
CHANCES IS EXPECTED MONDAY NIGHT.
ON TUESDAY...A COLD FRONT WILL MOVE SOUTHEAST INTO SOUTHERN ILLINOIS
AND SE MISSOURI BY LATE IN THE DAY. THE FRONT SHOULD ARRIVE DURING
PEAK HEATING AND INSTABILITY...SO WILL CONTINUE WITH POPS ABOVE MOS
GUIDANCE. PRECIP WATER VALUES WILL BE SOMEWHAT LOWER DUE TO A MORE
VEERED /WEST TO NORTHWEST/ DEEP LAYER FLOW...WHICH IS WHY POPS WILL
BE KEPT BELOW THE LIKELY CATEGORY. FLOW FIELDS WILL BE SOMEWHAT
STRONGER WITH THIS SYSTEM...SO THE POTENTIAL FOR ISOLATED SEVERE
STORMS EXISTS. CONVECTION SHOULD DIMINISH WITH THE PASSAGE OF THE
COLD FRONT ACROSS THE LOWER OHIO VALLEY LATE TUESDAY NIGHT.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 215 PM CDT SUN JUL 21 2013
THE MODELS ARE IN GENERAL AGREEMENT WITH FRONT ALONG OUR SOUTHERN
BORDER BY 12Z WED. HOWEVER THE GFS AND THE NAM PUSH IT ON THROUGH
LIMITING ANY PRECIP CHC AFTER 12Z WED. THE 00Z SUNDAY ECMWF LINGERS
PRECIP OVER THE AREA ALL DAY WED. CURRENT GRIDS REFLECT HIGHEST PROB
WOULD BE OVER SEMO AND LATEST RUNS SUPPORT THAT. HOWEVER WILL TRY TO
LOWER POPS NORTH AND EAST AS PREVIOUS SHIFT DID AND CONTINUE THE
TREND TOWARD A DRIER WED. IF THE 12Z ECMWF FOLLOWS THAT TREND THE
MID SHIFT WILL BE ABLE TO BETTER DEFINE THE CHC. SO THIS TIME FRAME
REMAINS A LITTLE SUSPECT FOR NOW WITH EITHER NORTH WINDS VIA NAM GFS
OR STALLED FRONT ECMWF. THE 12Z UKMET SHOWS THE FRONT ALONG THE
SOUTHERN BORDER AS WELL BUT THE RUN ENDS AT 12Z BUT APPEARS TO FAVOR
THE WETTER ECMWF.
FOR THE LATE WEEK CHC THE THE GFS BRINGS A FRONT THROUGH BUT THE
ECMWF AND DGEX BRING AN MCS OUT OF THE CENTRAL PLAINS FRIDAY WITH A
COLD FRONT IN ITS WAKE SATURDAY. THE GFS IS A LITTLE VOID OF THE MCS
FEATURE AND WILL LEAN TOWARD THE ECMWF AND DGEX SOLUTION...BUT USE
THE SLOWER TIMING OF THE ECMWF FOR THIS FEATURE. WILL MAINTAIN A
SLGT CHC SAT NGT IN THE EAST. WILL KEEP SUNDAY DRY WITH MUCH COOLER
AND DRIER AIR COMING INTO THE REGION.
AS FOR TEMPS IF THE EXTENDED INIT COMES TO FRUITION IT WILL BE A
MUCH COOLER AND WE COULD SEE SOME RECORD OR NEAR RECORD COOL TEMPS
EARLY NEXT WEEK. THE OPPOSITE OF LAST SUMMER RECORD SETTING HEAT.
&&
.AVIATION...
ISSUED AT 1233 AM CDT MON JUL 22 2013
WITH THE EXCEPTION OF SOME SHORT-LIVED IFR CIGS IN SWRN IND...CIGS
SHOULD BE VFR/MVFR OUTSIDE OF TSTM ACTIVITY...WHICH IS EXPECTED TO
OCCUR AT THE FOUR TAF SITES PRIMARILY BETWEEN ABOUT 06Z IN THE WEST
TO AS LATE AS 13Z IN THE EAST AS UPPER LEVEL ENERGY MOVES THROUGH.
WINDS WILL BE QUITE VARIABLE OVERNIGHT...BUT SHOULD SETTLE INTO A
SWRLY DIRECTION AFTER SUNRISE. EXPECT IMPROVING CONDITIONS AS THE
DAY GOES ON. MVFR VSBYS DUE TO FOG/RAIN SHOULD BE COMMON OUTSIDE
TSTMS OVERNIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...MY
SHORT TERM...MY
LONG TERM...KH
AVIATION...DB
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
256 AM EDT MON JUL 22 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE
EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY
STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES.
MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST
ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LATEST WX ANALYSIS SHOWS WEAKENING SFC FRONT FROM JUST SOUTH OF
LONG ISLAND NY...EXTENDING W-SW BACK INTO THE OHIO AND MIDDLE
MISSOURI VALLEYS. BULK OF CONVECTION WHICH ERUPTED ALONG SFC
TROUGH...AND DUMPED BETWEEN 3 AND 5 INCHES OVER PARTS OF THE
PIEDMONT AND MIDDLE PENINSULA EARLIER THIS EVENING...HAVE GREATLY
DIMINISHED IN INTENSITY AND AREAL CVG WITH LOSS OF HEATING AND
AS NOCTURNAL STABILITY SETS IN. HRRR HAS HANDLED TRENDS RATHER
WELL THIS EVENING AND HV CONTINUED TO LEAN IN ITS DIRECTION
OVERNIGHT. OVERALL, WHILE INSTABILITY AND SYNOPTIC SCALE FORCING
WANE SIGNIFICANTLY OVERNIGHT, WEAK LLVL CONVERGENCE ALONG THE
TROUGH AXIS PERSISTS. THUS, WILL RETAIN A SLIGHT CHC/LOW CHC POP
FOR AN ISO TO WIDELY SCT SHRA AFTER MIDNIGHT. ANOTHER WARM AND
HUMID OVERNIGHT IS EXPECTED WITH LOWS IN THE LOW/MID 70S...UNDER A
PARTLY TO MOSTLY CLOUDY SKY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE
BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS
TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT
OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY
AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE
FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN
SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF
SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH
DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM
THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS
RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN
FROM SLOW MOVING STORMS.
THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY
WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE
THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY
LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W.
HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO
WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER
80S TO LOW 90S.
THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE
REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST
BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME.
HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH
THE PERIOD SHOULD RANGE FROM 70-75.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT
EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR
JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA.
WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT.
THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH
AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL
NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW
CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S
THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN
MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE
PERIOD.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
LGT AND VRB WNDS THIS MRNG WITH A WEAK TROF OF LO PRES IN THE
VICINITY. LO-LVL MOISTURE TRAPPED UNDER A WEAK INVERSION WILL LEAD
TO LIFR CONDS OVER RIC FOR AT LEAST THE NEXT 6 HR...WITH MVFR
VSBYS FOR SBY...AND VFR ELSEWHERE WHERE TEMP/DEWPT SPREADS ARE
LARGER.
FOR DAYTIME TDY...AS WITH YESTERDAY EXPECT SCT AFTN/EVENG
SHRAS/TSTMS. THUNDER PSBL AS WELL BUT KEPT OUT OF THE TAFS FOR NOW
DUE TO UNCERTAINTIES SUCH AS TIMING. VSBY/CIG REDUCTIONS LIKELY IN
HEAVIER SHRAS/TSTMS. LO CLDS MAY PERSIST FOLLOWING THE RAIN TNGT
ALONGSIDE DIMINISHING WINDS WITH THE FRNTAL BNDRY IN THE VICINITY.
OUTLOOK...SCT MAINLY AFTN AND EARLY EVENING TSTMS CAN BE EXPECTED
TUE THROUGH FRI. AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN.
PATCHY IFR FOG NEAR SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR
IS INDICATED.
&&
.MARINE...
SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA
WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS
ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME
HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND
EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES.
EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/LKB
NEAR TERM...MAM
SHORT TERM...AJZ/LKB
LONG TERM...TMG
AVIATION...MAS/JEF
MARINE...LSA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
457 AM EDT MON JUL 22 2013
.SYNOPSIS...
ISSUED AT 407 AM EDT MON JUL 22 2013
HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH
ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE
NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS
THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS
NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS
AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF
OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO
NORTHERN MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 407 AM EDT MON JUL 22 2013
INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN
CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE
A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT.
OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING
ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME
ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN
MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER
FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN
BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF
07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS
THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX
LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH
THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST
NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A
SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND
WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE
LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR
NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW
OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN
RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY
ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE
OF LAKE MICHIGAN.
CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A
FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER
LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH
LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH
INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH
BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF
THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME
POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY
MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS
WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF
CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A
SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER
LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION
THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT
NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES
NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN.
THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY
AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS
RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY
IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL
PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM
ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE
LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW
SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z.
INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE
UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST
CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS
CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL
LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T
LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER
PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT
BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY
WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY
AREAS.
THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE
THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN
ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z.
BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A
LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD
1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE
SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST
AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING
EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL
TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY
CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE
OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND
MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY
SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF
THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S
THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE
BOUNDARY.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON JUL 22 2013
THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC
TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT
WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY
EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK
WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING
STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER
RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF
THE NEXT WORK WEEK.
TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT
UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY
MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN
THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD.
TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY
COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN
THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH
THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL
SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL
WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN
OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO
ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES
INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW
WISCONSIN.
THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE
AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE.
TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS
AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT.
REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL
RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS
THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT
IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW
OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME
TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET
EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED
ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A
RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL
ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED
LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING
RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES
FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE
APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES
IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND
LOWER 70S FOR THE UPCOMING WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 216 AM EDT MON JUL 22 2013
RETURN SOUTHERLY FLOW ON THE BACKSIDE OF THE SURFACE HIGH WILL
ALLOW LOW/MID LEVEL CLOUDS TO MOVE INTO AND/OR DEVELOP ACROSS
NORTHERN LOWER MICHIGAN THE REST OF THE NIGHT AND INTO THE
AFTERNOON HOURS. HEATING OF THE DAY SHOULD ALSO HELP FIRE OFF A
FEW SHOWERS AND THUNDERSTORMS...MOST LIKELY TO IMPACT PLN AND APN
AWAY FROM THE STABILIZING INFLUENCES OF LAKE MICHIGAN. A COLD
WILL APPROACH THE AREA THROUGH THE LATE EVENING AND OVERNIGHT
HOURS...GIVING BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND
STORMS. OVERALL...VFR CONDITIONS WILL BE THE RULE...THOUGH OF
COURSE...LOCALIZED WORSE CONDITIONS ARE ALWAYS POSSIBLE NEAR ANY
THUNDERSTORMS. LIGHT SOUTHEAST WINDS THROUGH SUNRISE WILL GIVE WAY
TO SOME GUSTY SOUTHWEST CONDITIONS THROUGH THE DAY...WITH GUSTS OF
15-20 KNOTS POSSIBLE. LOW LEVEL WIND SHEAR WILL BECOME AN ISSUE
TOWARD SUNSET.
&&
.MARINE...
ISSUED AT 407 AM EDT MON JUL 22 2013
LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST
AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING
THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT
ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND
TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS.
THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH
THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS
THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF
SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD
PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE
WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING
HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED.
HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK...
GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH
THURSDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...SD
SHORT TERM...DL
LONG TERM...SD
AVIATION...LAWRENCE
MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 AM EDT MON JUL 22 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 410 PM EDT SUN JUL 21 2013
WV IMAGERY AND RUC ANALYSIS INDICATED MID/UPPER LEVEL LOWS OVER NE
CANADA AND NRN BC RESULTING IN ZONAL TO WNW FLOW OVER SRN CANADA AND
THE NRN CONUS. AN AREA OF CONVECTION HAS PERSISTED AHEAD OF
PROMINENT SHORTWAVE TROUGH LOCATED OVER SRN SASK. THE COMBINATION
OF A WEAK SHRTWV AND WAA AHEAD OF A WARM FRONT OVER IA SUPPORTED
ANOTHER AREA OF SHRA/TSRA OVER CNTRL/SRN WI.
TONIGHT...RADAR AND SHORT RANGE MODELS SUGGEST THAT ANY SHRA/TSRA
ASSOCIATED WITH THE WI SHRTWV WILL NOT IMPACT THE CWA THIS EVENING.
LINEAR EXTRAPOLATION OF THE SASK SHRTWV AND CONVECTION MOVING INTO
THE SW CORNER OF MANITOBA WOULD BRING THE PCPN WITH THIS FEATURE
INTO WRN UPPER MI BTWN 09Z-11Z. HOWEVER...AS THIS FEATURE MOVES INTO
THE AIRMASS OVER THE NRN LAKES AND AWAY FROM THE MORE FAVORABLE
MUCAPE OVER NRN MN...EXPECT THAT THE CONVECTION WILL WEAKEN.
SO...THE FCST ONLY MENTIONS CHANCE POPS WITH ISOLD TS POSSIBLE
OVERNIGHT.
MONDAY...AFTER THE INITIAL BATCH OF SHRA/TSRA MOVES THROUGH MAINLY
THE NW CWA EARLY MONDAY...THE FORECAST BECOMES MORE UNCERTAIN. THE
AMOUNT OF DAYTIME WARMING AND RESULTING INSTABILITY WILL BE IMPACTED
BY LINGERING CLOUD COVER IN THE WAA REGIME. IF THE CLOUDS BREAK UP
ENOUGH AND TEMPS CLIMB TO AROUND 80 AS FCST WITH DEWPOINTS LOWER
60S...MLCAPE VALUES WOULD PUSH INTO THE 1000-1500 J/KG RANGE. STRONG
LOW LEVEL AND A VEERING WIND PROFILE IS EXPECTED WITH 0-6KM BULK
SHEAR TO AROUND 40 KT WITH CURVED HODOGRAPHS. THAT AMOUNT OF
INSTABILITY COMBINED WITH A FAVORABLE SHEAR PROFILE WOULD SUPPORT
POTENTIAL FOR SEVERE STORMS INCLUDING ISOLATED SUPERCELLS. THE MAIN
TRIGGER FOR CONVECTION WOULD BE THE LIMITED FORCING WITH THE NRN
ONTARIO SHRTWV TAIL ALONG WITH A PREFRONTAL TROUGH AND LAKE BREEZE
BOUNDARIES AHEAD OF THE MAIN COLD FRONT MOVING INTO THE AREA DURING
THE EVENING. HOWEVER...THE SEVERE WEATHER THREAT WILL BE
CONDITIONAL...DEPENDENT ON THE AMOUNT OF INSTABILITY THAT DEVELOPS.
THE GREATEST CHANCE FOR HIGHER CAPE VALUES IS EXPECTED NEAR THE WI
BORDER FROM IWD-IMT IN LINE WITH SPC SREF SVR CALIBRATED PROB AND
SPC OUTLOOK. THERE IS ALSO SOME UNCERTAINTY WITH TIMING...BUT THE
GREATEST CHANCES WOULD LIKELY FROM W INTO CNTRL UPPER MI.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 449 AM EDT MON JUL 22 2013
TUESDAY...THE CWA WILL BE BETWEEN A DEPARTING SFC LOW NEAR JAMES BAY
AND A SFC HIGH OVER NW MN AT 12Z. THE TIGHT PRESSURE BETWEEN THE
SYSTEM AND BEHIND THE COLD FRONT THAT MOVED THROUGH MON
EVENING/NIGHT WILL LEAD TO GUSTY NLY WINDS...BUT THE GRADIENT AND
WINDS WILL DECREASE LATE IN THE DAY. BECAUSE OF THE GUSTY
WINDS...WAVES WILL INCREASE AND ASSOCIATED SWIM RISK WILL BE HIGH.
TEMPS WILL BE COOLER THAN TODAY...WITH HIGHS IN THE 60S NEAR LAKE
SUPERIOR TO AROUND 70 WELL INLAND.
TUESDAY NIGHT...TEMPS WILL FALL TO OR BELOW 40F OVER PARTS OF THE
INTERIOR W DUE TO CLEAR SKIS AND CALM WINDS.
WEDNESDAY...INCLUDED SLIGHT POPS IN THE AFTERNOON AS MODELS CONTINUE
TO INDICATE A CONVECTIVELY INDUCED SHORTWAVE MOVING THROUGH NRN WI.
NOT TOO SURE ABOUT WHAT WILL END UP HAPPENING WITH THE
SHORTWAVE...BUT THOUGHT IT WAS WORTH THE SLIGHT POPS. TEMPS WILL BE
A BIT WARMER THAN TUESDAY...WITH HIGHS IN THE MID 60S NEAR LAKE
SUPERIOR TO THE MID 70S INLAND.
UNCERTAINTY INCREASES ON A DAILY BASIS WED NIGHT THROUGH SUN AS
MODELS BRING MULTIPLE ROUNDS OF UPPER LEVEL ENERGY INTO THE
REGION...BUT DIFFER SIGNIFICANTLY BETWEEN MODELS AND BETWEEN RUNS ON
THE STRENGTH/PLACEMENT OF THAT ENERGY...WHICH WILL PLAY A CRITICAL
ROLE IN PRECIP CHANCES LATE IN THE WEEK AND INTO THE WEEKEND. WILL
JUST GO WITH THE CONSENSUS GUIDANCE DUE TO THE UNCERTAINTY...BUT
WILL NOT ALLOW POPS BE GET TOO HIGH. TEMPS ARE ALSO UNCERTAIN...BUT
IT APPEARS A WARMER DAY WILL BE IN STORE FOR THU...WITH COOLING
CONDITIONS FRIDAY INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 248 AM EDT MON JUL 22 2013
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE PERIOD. EXPECT
INCREASING MID CLOUDS LATE TONIGHT INTO MONDAY MORNING AHEAD OF AN
APPROACHING DISTURBANCE. SOME SHRA ARE POSSIBLE AT ALL SITES MON
MORNING AND TRIED TO TIME THESE WITH EITHER PROB30 GROUPS OR
PREVAILING. FRONT COMES THROUGH BY EVENING AND SWITCHES THE WIND TO
THE NORTHWEST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EDT SUN JUL 21 2013
SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS LATE TONIGHT AND MONDAY
AHEAD OF A LOW PRESSURE TROUGH MOVING THROUGH THE AREA. NORTH TO
NORTHWEST WINDS WILL THEN INCREASE TO 20-25 KNOTS BY LATE MONDAY NIGHT
INTO TUESDAY BEHIND THE TROUGH/COLD FRONT MOVING THROUGH THE REGION.
WINDS ARE THEN EXPECTED TO REMAIN BELOW 20 KNOTS TUE NIGHT THROUGH
THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
401 AM CDT MON JUL 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT MON JUL 22 2013
EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE
TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE
SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING
FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN
OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE
ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE
TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT
COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS
SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE
ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT
BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE
22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING
SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE
SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL
WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING
THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE
INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR
STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH
CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG
THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY
/MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK
SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW
FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35.
CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE
FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT.
HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST
CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE
AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH
GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS
TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND
LOWER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 AM CDT MON JUL 22 2013
MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY
PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS
IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF
CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A
BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT.
THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A
SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN
STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS
THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT
CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL
BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES
RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST
MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS
WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH
SATURDAY.
AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF
TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO
THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND
MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE
GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE
ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO
FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS
KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE
SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE
DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF
THE BUNCH.
FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN
IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ
FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN
A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK
TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES
IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED
OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS
MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR
ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE
POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY
POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE
BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF
MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA
OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE.
ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF
WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND
ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE
MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH.
IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS
WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE
22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD
LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK
TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED
LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE
ABLE MAKE A RUN AT THAT RECORD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1152 PM CDT SUN JUL 21 2013
THUNDERSTORMS OVER THE DAKOTAS ARE INDEED WEAKENING AS EXPECTED...
BUT A FEW SHOWERS MAY BE IN THE VICINITY OF AXN DURING THE FIRST
SEVERAL HOURS OF THE TAF PERIOD. HAVE A HARD TIME SEEING THEM
MAKING IT AS FAR EAST AS STC OR AS FAR SOUTH AS RWF. THE FRONT
WILL LIKELY BECOME MORE ACTIVE AGAIN LATE MONDAY MORNING OVER ERN
MN AND MONDAY AFTERNOON OVER WRN WI. CONTINUED THE PROB30S UNTIL
FROPA WITH WINDS VEERING NORTHWEST AND INCREASING WITH GUSTS TO
20 KT UNTIL EARLY EVENING.
KMSP...BIGGEST CONCERN CONTINUES TO BE WHETHER THE IFR CIGS OVER
WRN WI CAN MAKE IT AS FAR WEST AS MSP EARLY MONDAY. CURRENT
INDICATIONS ARE THAT THEY WILL NOT...BUT IT WILL BE CLOSE.
CONTINUED SCT MVFR MENTION FOR NOW.
/OUTLOOK FOR KMSP/
TUE...VFR. WINDS N 5 TO 10 KT.
WED...VFR. MVFR WITH A CHANCE OF SHRA/TSRA LATE NIGHT. WINDS LGT
AND VRB.
THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS LGT AND VRB.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...MPG
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
431 AM CDT MON JUL 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT MON JUL 22 2013
THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST
THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN
COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH
SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL
GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO
NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND
SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER
BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF
THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE
UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE
EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF
THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR
THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR
FLOW.
THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF
DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS
WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND
MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR
SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS
TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE
WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED
LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS
COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING
CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES
THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE
RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH
WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS
ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND
06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD
NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY
CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE
DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST
OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED
CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD
PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF
AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE
MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE
AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY
THEN.
THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS
AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST
AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR
VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY
WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE
TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE
LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST
STORMS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 349 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS WILL BE
CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND
TEMPERATURES.
MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE
PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN
DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A
LITTLE DIFFERENT WITH EACH MODEL.
THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY
NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS
SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS
DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE
EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE
AREA. TEMPERATURES WILL BE COOLER THAN TODAY.
A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND
INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY.
TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY
WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF
THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE
IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY
NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME
LINGERING THUNDERSTORMS.
FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL
WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY
MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE
OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER
SIDE DURING THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1246 AM CDT MON JUL 22 2013
WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS...BUT ANY
THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY
OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL
MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY
BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE
PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE THE
NORTHEAST. AM CALLING FOR VFR CONDITIONS THROUGHOUT THE
PERIOD...BUT WILL HAVE TO WATCH OUT FOR SOME POSSIBLE LOW CLOUD
DEVELOPMENT TO THE SOUTH OF KGRI THAT HAS A SLIM CHANCE OF
IMPACTING KGRI.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
355 AM CDT MON JUL 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT MON JUL 22 2013
THUNDERSTORMS WILL MOVE EAST SOUTHEAST OUT OF THE FORECAST AREA THIS
MORNING WITH CLEARING SKIES TO THE WEST. COOL FRONT OVER CENTRAL
SOUTH DAKOTA IS PROGGED TO MOVE SOUTH ACROSS WESTERN NEBRASKA TODAY
AND BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT THIS AFTERNOON OVER
THE SOUTHEAST PORTION OF THE FORECAST AREA. TEMPERATURES SIMILAR TO
YESTERDAYS WITH SOME UPPER 80S NORTH AND LOW 90S SOUTH. FOCUS THEN
SHIFTS NORTH THROUGH THE EARLY MORNING HOURS OF TUESDAY WITH
BOUNDARY LYING ACROSS WESTERN NEBRASKA AND WEAK WAVE MOVING THROUGH
FAST NORTHWEST FLOW EXPECTED TO FIRE OFF SOME THUNDERSTORMS
GENERALLY NORTH OF HIGHWAY 2 THROUGH THE EARLY MORNING. LOWS AROUND
60.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 355 AM CDT MON JUL 22 2013
MAIN FORECASTING CONCERN IN THE EXTENDED PERIODS CONTINUES TO BE
PRECIPITATION CHANCES...ESPECIALLY SINCE TIMING AND LOCATIONAL
DIFFERENCES REMAIN PROBLEMATIC GIVEN THE LOW RUN TO RUN
CONSISTENCY IN THE SMALL AMPLITUDE PERTURBATIONS WITHIN
NORTHWESTERLY FLOW. THE FIRST OF THESE WEAK PERTURBATIONS IS SHOWN
TO CROSS THE NORTHERN/CENTRAL PLAINS TUESDAY INTO EARLY
WEDNESDAY...BRINGING A SLIGHT CHANCE OF STORMS BACK TO THE AREA
FROM NORTHWEST TO SOUTHEAST. PARAMETERS ARE NOT TOO FAVORABLE FOR
SEVERE DEVELOPMENT AS SHEAR IS SUFFICIENT...BUT INSTABILITY IS
SOMEWHAT LACKING. THEREAFTER...THE NEXT BEST SHOT AT WIDESPREAD
PRECIPITATION COMES EARLY THURSDAY AS THE GFS AND EC LIFT A DECENT
SHORTWAVE INTO SOUTHWESTERN/WESTERN NEBRASKA. FRONTAL SUPPORT
REMAINS TO THE SOUTH AND WEST OF THE FORECAST AREA...WITH THE BEST
INSTABILITY SOUTH AS WELL...HOWEVER BOTH MODELS GENERATE QPF
ACROSS MUCH OF THE CWA AS MID TO UPPER TROPOSPHERIC COOLING
ASSOCIATED WITH THE WAVE OCCURS. WILL LIMIT POPS IN THE 40 PERCENT
RANGE FOR NOW AS STRONGEST FORCING IS REMOVED FROM THE CWA. THE
ACTIVE NORTHWEST PATTERN CONTINUES INTO LATE WEEK/WEEKEND WITH
ADDITIONAL WAVES BRINGING CONTINUED PRECIPITATION CHANCES TO THE
AREA...BUT WITH ALL THE WAFFLING IN THE LONG RANGE PERIODS WILL
LIMIT ALL POPS AT 25 PERCENT OR LESS BEYOND FRIDAY MORNING UNTIL
TIMING AND LOCATIONAL DIFFERENCES ARE RESOLVED.
AS FOR TEMPERATURES...THANKS TO EXPECTED
CLOUDS...PRECIPITATION...AND EASTERLY TO SOUTHEASTERLY LOW LEVEL
FLOW RECYCLED FROM COOL MIDWEST HIGH...HIGHS SHOULD FALL BACK INTO
THE 80S FOR MOST LOCATIONS...ESPECIALLY THURSDAY AND BEYOND. THE
WARMEST READINGS WILL ONCE AGAIN BE CONFINED TO OUR FAR WEST...IN
CLOSER PROXIMITY TO A SOUTHWESTERN UPPER LEVEL RIDGE ON TUESDAY WITH
LOWER 90S POSSIBLE. LOWS WILL REMAIN SEASONAL THROUGH THE EXTENDED
PERIODS...WITH MAINLY 60S ANTICIPATED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1122 PM CDT SUN JUL 21 2013
THE LATEST CONSENSUS OF THE HRRR...NAM AND RAP MODELS SUGGESTS
ISOLATED THUNDERSTORMS WOULD CONTINUE THROUGH ABOUT 12Z MONDAY
MORNING AND THEN REDEVELOP BETWEEN 21Z-00Z MONDAY AFTERNOON. GIVEN
THE STRONG CAP OPERATING MONDAY AFTN...JUST ISOLATED STORMS WOULD
BE EXPECTED GENERALLY FROM KBBW WEST THROUGH KLBF...KIML AND KOGA.
STORM ACTIVITY...IF IT DEVELOPS...WOULD EXIT THE FCST AREA BY
ROUGHLY 03Z. A THIRD SOUTHEASTWARD MOVING AREA OF THUNDERSTORMS
COULD THEN BEGIN AFFECTING NRN NEB AROUND 06Z MONDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...POWER
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
304 AM CDT MON JUL 22 2013
.DISCUSSION...
PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE
CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z
WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA
INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL
NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA
BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA
THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY
STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN
THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND
OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY
EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE
WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO
THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH
SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35
KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND
THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING.
SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION
REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST
THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH
PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE
SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY
WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS
THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST
THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S
ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL
SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER
INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD
LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH
SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS
ARE EXPECTED TUESDAY AS WELL.
THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY
THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING
THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN
PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A
SMALL PRECIP CHANCE SUNDAY INTO MONDAY.
DEWALD
&&
.AVIATION...06Z TAFS FOR KOMA...KOFK...KLNK SOME PATCHY FOG
POSSIBLE MONDAY MORNING AT KOMA AND KLNK WITH LIGHT WINDS AND HIGH
LOW LEVER MOISTURE. A COLD FRONT WILL PUSH ACROSS THE AREA WITH
SOUTH/SOUTHWEST WINDS VEERING AROUND TO THE NORTHWEST WITH THE
FRONT...AFTER 15Z AT KOFK MONDAY. SHOWERS AND THUNDERSTORMS MAY
DEVELOP ALONG THE FRONT WITH GOOD MOISTURE AND INSTABILITY. FOR
NOW INCLUDED A COUPLE OF HOURS WITH SHOWERS IN THE AFTERNOON AND
EARLY EVENING AT KOMA AND KLNK AND CAN ADD TSRA WHEN THERE IS
BETTER CONFIDENCE IN THE COVERAGE AND TIMING.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1126 PM CDT SUN JUL 21 2013
.SYNOPSIS...
ISSUED AT 333 PM CDT SUN JUL 21 2013
H5 ANALYSIS FROM THIS MORNING...HAS TWO AREAS OF HIGH
PRESSURE ALOFT...THE FIRST OVER NEVADA...AND A SECOND OFF THE
CAROLINA COAST. IN BETWEEN...A TROUGH OF LOW PRESSURE EXTENDED
ACROSS THE SRN PLAINS FROM KANSAS INTO NERN TX. ACROSS THE NRN TIER
OF STATES...INCLUDING THE CENTRAL AND NRN PLAINS...BROAD WEST
NORTHWESTERLY AND WESTERLY FLOW EXTENDED FROM THE PACIFIC NW...INTO
THE CENTRAL AND NRN PLAINS...EWD INTO THE MID ATLANTIC AND NEW
ENGLAND. UPSTREAM OF THE CENTRAL PLAINS...A DECENT SHORTWAVE WAS
NOTED OVER SRN ALBERTA...AND A SECOND STRONGER WAVE OVER NWRN
PORTIONS OF BRITISH COLUMBIA. AT THE SURFACE...A CONVECTIVE INDUCED
MESO HIGH WAS LOCATED OVER SWRN NEBRASKA...WITH DECENT SRLY WINDS
NOTED ACROSS THE PANHANDLE ATTM. AS OF 3 PM CDT...TEMPERATURES
RANGED FROM 84 AT AINWSWORTH...TO 90 AT IMPERIAL.
&&
.UPDATE...
ISSUED AT 921 PM CDT SUN JUL 21 2013
THE HRRR SHOWS THE STORMS ACROSS NW NEB FILLING IN AND BECOMING A
LINE OF TSTMS WHICH SWEEP THE FCST AREA OVERNIGHT. THIS IS
PROBABLY OVERDONE. THE RAP SHOWS NO STORMS AT ALL BUT INDICATES A
20 TO 30 KT LOW LEVEL JET RUNNING DUE NORTH UP THROUGH WRN NEB
TONIGHT. PWAT SHOULD INCREASE TO 1.25 INCHES AND MAYBE MORE
ACCORDING TO THE RAP. SO THE FORECAST HAS BEEN UPDATED FOR SCATTERED
TSTMS WHICH IS A COMPROMISE OF THE HRRR AND RAP MODELS. NOTE THE 18Z
NAM SHOWED ISOLATED STORMS MOVING SOUTHEAST TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 333 PM CDT SUN JUL 21 2013
WEAK WAVE IS MOVING ACROSS EAST CENTRAL WYOMING THIS AFTERNOON. THIS
WAVE WILL BE THE FOCUS FOR SOME ISOLATED THUNDERSTORMS. LACKING SOME
MOISTURE AS DEW PTS IN THE LOWER TO MID 50S. LOW LEVEL JET ALONG THE
FRONT RANGE TONIGHT AND WILL AID IN THUNDERSTORM DEVELOPMENT.
ATMOSPHERE TOOK A BEATING LAST NIGHT AND EARLY THIS MORNING...SO
CONFIDENCE IS LOW ON HOW WIDESPREAD THE COVERAGE WILL BE...HOWEVER
SEVERAL REMNANT BOUNDARIES COULD HELP TO SPARK DEVELOPMENT. SINCE
THERE IS NOT MUCH OF A CU FIELD...AND ONLY ONE CELL HAS GOTTEN GOING
OVER WYOMING...EXPECT COVERAGE TO BE ISOLD. AS FOR TEMPS...THEY
SHOULD COOL BACK INTO THE 60S...ALTHOUGH LOCALLY IN THE WEST A BRIEF
DIP BELOW 60 IS POSSIBLE.
TOMORROW RIDGE REMAINS DOMINATE TO THE SOUTHWEST...WITH MOSTLY SUNNY
SKIES THROUGH MOST OF THE DAY. HIGHS INTO THE LOWER/MID 90S ACROSS
THE SW TO THE UPPER 80S ACROSS N CENTRAL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 333 PM CDT SUN JUL 21 2013
MID RANGE...MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING
CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES...AS TIMING AND
LOCATION REMAIN PROBLEMATIC GIVEN THE NORTHWESTERLY FLOW. FOR MONDAY
NIGHT...MID LEVEL HTS WILL BEGIN TO INCREASE AS HIGH PRESSURE ALOFT
BUILDS EAST OF THE DESERT SOUTHWEST. INCREASED MID LEVEL WAA WILL
RESULT...LEADING TO INCREASED POPS MONDAY NIGHT INTO EARLY TUESDAY.
WILL KEEP POPS AS SLIGHTS ATTM...AS DECENT JET SUPPORT IS FOCUSED
EAST OF THE AREA. A SECONDARY AREA OF MID LEVEL WAA WILL TRACK
ACROSS THE CWA FROM NW TO SE ON TUESDAY INTO TUESDAY EVENING. WILL
HOLD ONTO SLIGHT CHANCES FOR PCPN SINCE THE BEST JET SUPPORT REMAINS
EAST OF THE AREA. BY WEDNESDAY AFTERNOON...BOTH THE NAM AND GFS FORCE
A DECENT SHORTWAVE INTO WRN NEBRASKA LATE IN THE DAY...LIFTING THIS
EAST INTO WEDNESDAY NIGHT. WILL START POPS OFF LOW IN THE WEST...AS
BETTER CHANCES WILL ARRIVE WEDNESDAY NIGHT AS THE FORECAST AREA IS IN
THE RIGHT REAR QUAD OF THE EXITING JET.
LONG RANGE...WEDNESDAY NIGHT THROUGH SUNDAY...ACTIVE WESTERLY AND
NORTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS THE CENTRAL AND
NORTHERN PLAINS INTO THE EXTENDED PERIODS. ATTM...THE BEST CHANCES
FOR RAIN APPEAR TO LIE ON WEDNESDAY NIGHT AND FRIDAY NIGHT AS THE
FORECAST AREA IS IN A FAVORABLE EXIT REGION OF THE H300 JET. HAVE
INCREASED POPS INTO THE 50 PERCENT RANGE FOR WEDNESDAY NIGHT AND
THURSDAY AND WILL KEEP CHANCE POPS GOING INTO THURSDAY NIGHT. THE
EXTENSION OF POPS INTO THURSDAY NIGHT...IS TO ACCOMMODATE THE LATEST
ECMWF WHICH IS 12 HRS SLOWER THAN THE LATEST GFS SOLN. TEMPERATURES
FOR THE WEEK WILL COOL BACK INTO THE 80S...THANKS TO EXPECTED CLOUD
COVER AND SERLY AND ERLY UPSLOPE WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1122 PM CDT SUN JUL 21 2013
THE LATEST CONSENSUS OF THE HRRR...NAM AND RAP MODELS SUGGESTS
ISOLATED THUNDERSTORMS WOULD CONTINUE THROUGH ABOUT 12Z MONDAY
MORNING AND THEN REDEVELOP BETWEEN 21Z-00Z MONDAY AFTERNOON. GIVEN
THE STRONG CAP OPERATING MONDAY AFTN...JUST ISOLATED STORMS WOULD
BE EXPECTED GENERALLY FROM KBBW WEST THROUGH KLBF...KIML AND KOGA.
STORM ACTIVITY...IF IT DEVELOPS...WOULD EXIT THE FCST AREA BY
ROUGHLY 03Z. A THIRD SOUTHEASTWARD MOVING AREA OF THUNDERSTORMS
COULD THEN BEGIN AFFECTING NRN NEB AROUND 06Z MONDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...MASEK
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
148 AM EDT MON JUL 22 2013
.SYNOPSIS...
FAIRLY SEASONABLE TEMPERATURES AND A NORMAL SCATTERING OF AFTERNOON
STORMS ARE EXPECTED THE NEXT SEVERAL DAYS...COMPLIMENTS OF BERMUDA
HIGH PRESSURE. A COLD FRONT DROPPING CLOSE TO THE REGION ON THURSDAY
WILL STALL AND KEEP THE WEATHER A BIT MORE UNSETTLED.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 2:00 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
WATER VAPOR IMAGERY SHOWS AN ANTICYCLONIC (CLOCKWISE) SPIN OVER
THE EASTERN CAROLINAS. MODELS ARE STRUGGLING TO CONSISTENTLY
LOCATE REGIONS OF CYCLONIC CURVATURE THAT MAY BE HELPING SUSTAIN
CLUSTERS OF SHOWERS AND T-STORMS. AGAIN REFERENCING WATER VAPOR
IMAGERY IT APPEARS ONE UPPER DISTURBANCE LIES ACROSS CENTRAL NORTH
CAROLINA INTO WEST-CENTRAL SOUTH CAROLINA...WHILE A SECOND MORE
QUIESCENT DISTURBANCE LIES OFF THE GEORGIA AND SOUTHERN SOUTH
CAROLINA COAST.
THE AIRMASS REMAINS SEASONABLY WARM...BUT MOISTURE CONTENT AS
MEASURED BY PRECIPITABLE WATER IS VERY HIGH: 2.2 INCHES. LAPSE RATES
ARE NOT PARTICULARLY STEEP BUT ARE JUST LARGE ENOUGH THROUGH THE
900-600 MB LAYER TO PROMOTE GOOD UPDRAFT ACCELERATION. IR SATELLITE
SHOWS CLOUD TOP TEMPERATURES MAINTAINING LARGE AREAS COLDER THAN
-60C. BASED ON RECENT TRENDS AND THE LAST SEVERAL HRRR RUNS (WHICH
HAVEN`T BEEN BAD THIS EVENING) THE CONVECTION ACROSS THE SC PEE DEE
REGION SHOULD LARGELY DISSIPATE WITHIN THE NEXT 2-3 HOURS WHILE NEW
CONVECTION DEVELOPS CLOSER TO THE COAST...ESPECIALLY THE NC COAST.
AFTER 2 AM MOST OF THE CONVECTION SHOULD EXIT THE LANDMASS AND MOVE
EASTWARD INTO THE OCEAN.
HIGH-REFLECTIVITY (>50DBZ) CORES HAVE SO FAR REMAINED VERY LOW IN
THE STORMS...BARELY ABOVE THE FREEZING LEVEL. THIS IS CORRELATED
WITH EFFICIENT HEAVY RAIN PRODUCTION BUT NOT WITH SEVERE WEATHER.
SINCE CELL MOVEMENT REMAINS SLOW FROM THE WEST FLOODING WILL BE THE
PRIMARY THREAT TO WATCH FOR THE NEXT SEVERAL HOURS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...COPIOUS MOISTURE REMAINS IN PLACE ON MONDAY WITH
PRECIPITABLE WATER STILL ABOVE 2 INCHES. WHILE WIDESPREAD CLOUD
COVER INHIBITED INSOLATION AND THUS CONVECTIVE COVERAGE TODAY THIS
APPEARS A LITTLE LESS LIKELY MONDAY.FCST SOUNDINGS LESS INDICATIVE
OF WIDESPREAD SC EARLY IN THE DAY SO EXPECT BETTER HEATING AND THUS
COVERAGE OF STORMS. ITS HARD TO PIN DOWN ANY FAVORED AREAS FOR
HIGHER POPS...ABUT A LATE DAY UPPER VORT AND SFC TROUGH MAY FOCUS
ACTIVITY OVER WESTERN ZONES EVEN AS A LARGER SCALE DIURNAL WANING IS
UNDERWAY. A STRONGER VORT WILL SCOOT BY TO OUR NORTH ON
TUESDAY...PERHAPS AROUND MIDDAY. IN ITS WAKE WILL BE A SUPPRESSING
EFFECT ON CONVECTION AND SOME 20-30 POPS SEEM ALL THAT IS WARRANTED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...PATTERN ALOFT REMAINS AMPLIFIED THROUGH THE
PERIOD WITH 5H TROUGHING OVER THE EAST COAST AND RIDGING OUT WEST.
THIS MAINTAINS ACTIVE WEATHER ACROSS THE SOUTHEAST WITH PIEDMONT
TROUGH AND SEA BREEZE BEING THE FOCUS ON WED. FROM THU ON WEAK COLD
FRONT MOVES INTO THE REGION BUT STALLS WITH FLOW ALOFT BECOMING
PARALLEL TO THE SURFACE BOUNDARY. HAVE A HARD TIME BELIEVING THE
FRONT WILL MAKE IT TO THE COAST FOR ANY LENGTH OF TIME WITH THE 5H
TROUGH AXIS REMAINING WEST OF THE AREA. WEAK WAVES DEVELOPING ON THE
FRONT WILL BRIEFLY PUSH THE BOUNDARY TO THE COAST BEFORE ALLOWING IT
TO RETURN INLAND. IN ADDITION TO NUDGING THE FRONT EAST OR WEST
THESE WAVES SHOULD HELP GENERATE AND ENHANCE CONVECTION. TIMING THE
FEATURES AT THIS POINT IS DIFFICULT AT BEST SO WILL MAINTAIN CHANCE
POP THROUGH THE FORECAST PERIOD.
FRONT WILL SLOWLY DISSIPATE DURING THE SECOND HALF OF THE
PERIOD...EVENTUALLY MERGING WITH THE PIEDMONT TROUGH. NEXT WEEKEND A
SHORTWAVE MOVING INTO THE MS VALLY INDUCES A SURFACE LOW WHICH THEN
LIFTS NORTHEAST THROUGH THE OH VALLEY. COLD FRONT ASSOCIATED WITH
THE LOW MOVES INTO THE CAROLINAS LATE IN THE PERIOD. STRONGER 5H
TROUGH SUGGESTS THIS FRONT MAY HAVE A BETTER CHANCE OF REACHING OR
MOVING OFF THE COAST. AT THE VERY LEAST IT WILL RESULT IN AN
INCREASE IN PRECIP CHANCES FOR THE WEEKEND...ESPECIALLY SUN.
DAILY CONVECTION AND CLOUD COVER WILL KEEP HIGHS NEAR TO SLIGHTLY
BELOW CLIMO WHILE SOUTHERLY FLOW...MOISTURE AND LEFT OVER DEBRIS
CLOUD KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...AN AREA OF LIGHT TO MODERATE SHOWERS FROM KFLO TO KLBT
WILL GRADUALLY DISSIPATE OVER THE NEXT SEVERAL HOURS. AFTER THE
PRECIPITATION ENDS MVFR CONDITIONS WILL GIVE WAY TO IFR CIGS/VSBYS
AS FOG DEVELOPS. AT THE COASTAL TERMINALS...SHOWERS WILL OCCUR
MAINLY OFFSHORE THUS WILL INDICATE VCSH THROUGH SUNRISE. SCATTERED
CLOUDS AT THE IFR LEVEL WITH TEMPO BROKEN MVFR CEILINGS CAN BE
EXPECTED. TEMPO IFR CIGS SHOULD OCCUR MAINLY IN THE PRE-DAWN HOURS.
ANY IFR CIGS SHOULD RISE TO MVFR BY 14Z WITH VFR DEVELOPING LATE
MORNING INTO EARLY AFTERNOON. SHOULD BE A GOOD CHANCE OF VCSH AT THE
COASTAL TERMINALS BY NOON LOCAL WITH VCTS DEVELOPING AT KFLO/KLBT
WITH THE APPROACH OF AN UPPER IMPULSE. THIS ACTIVITY WILL LIKELY
PERSIST INTO THE EVENING HOURS.
EXTENDED OUTLOOK...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED THROUGH THURSDAY...WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR POSSIBLE. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 2:00 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
WINDS FINALLY SURGED UP IN THE LAST FEW HOURS BUT ARE STILL WELL
BELOW ADVISORY THRESHOLDS. RECENT GUSTS INCLUDE 21 KNOTS AT THE
FRYING PAN SHOALS BUOY...NORTH MYRTLE BEACH...AND OAK ISLAND...20
KNOTS ON BALD HEAD ISLAND...AND 19 KNOTS IN GEORGETOWN. THESE
STRONGER SOUTHWEST WINDS MAY CONTINUE THROUGH 11 PM OR MIDNIGHT
BEFORE A LANDBREEZE PRODUCES MUCH LIGHTER WEST-SOUTHWEST WINDS
NEAR THE BEACHES...SPREADING OUT AWAY FROM THE COAST OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...WEAK WAVE OF LOW PRESSURE NEAR DELMARVA WILL
VEER LOCAL FLOW SLIGHTLY TO A MORE WESTERLY DIRECTION THAN THE
TYPICAL SW FOR PART OF MONDAY. LATER IN THE DAY SW FLOW GETS
ESTABLISHED WITH ABOUT A 5KT INC IN SPEED. THIS TREND WILL CONTINUE
INTO MONDAY NIGHT BUT NOT TO WHERE CAUTIONARY HEADLINES WARRANTED AS
SEAS NOT EXPECTED TO BUILD QUITE ENOUGH WITHIN 20NM BORDER.
PIEDMONT TROUGHINESS DEVELOPS LATER FRIDAY AND SHOULD MAINTAIN
SLIGHTLY HIGHER WIND SPEEDS THAN WHAT SEASONABLE...15 TO 20KT MOST
ZONES. A LITTLE LIGHTER FLOW OVER SRN LEGS WHICH SHOULD PREVENT 5 FT
SEAS OFF GTOWN.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD
WITH WATERS IN BETWEEN BERMUDA HIGH AND PIEDMONT TROUGH/WEAK COLD
FRONT. WINDS AND SEAS WILL BE HIGHEST EARLY IN THE PERIOD. GRADIENT
RELAXES AS FRONT/TROUGH MOVE CLOSER TO THE COAST AND WEAK SURFACE
WAVES DEVELOP ON THE BOUNDARY. SPEEDS WILL BE 10 TO 15 KT WED THEN
DECREASE TO AROUND 10 KT FOR THU AND FRI. SEAS WILL FALL FROM 3 TO 4
FT ON WED TO AROUND 2 FT FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1152 PM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 1147 PM CDT SUN JUL 21 2013
LONE SEVERE STORM CONTINUES TO PROPAGATE SE INTO CENTRAL PORTION OF
THE FORECAST AREA WITH VERY LITTLE HAPPENING ELSEWHERE. CONTINUED
TO ADJUST POPS BASED ON CURRENT AND EXPECTED PCPN TRACK. NO OTHER
CHANGES MADE.
UPDATE ISSUED AT 945 PM CDT SUN JUL 21 2013
DEEP CONVECTION WEAKENED EARLY THIS EVENING AS IT MOVED INTO THE
FAR WESTERN FORECAST AREA. T IS NOW VERY ISOLATED WITH STRONGEST
CELL JUST NORTH OF LAKOTA. LOW LEVEL JET FORECAST TO INCREASE WITH
BEST CONVERGENCE ALONG INTERNATIONAL BORDER AREA OF MN OVERNIGHT.
HAVE MAINTAIN HIGHEST POPS THIS AREA THROUGH MOST OF THE NIGHT.
ELSEWHERE STORM POTENTIAL MORE IN QUESTION AND HAVE OVERALL
DECREASED POPS SIGNIFICANTLY ACROSS SOUTH HALF OF FA WITH LACK OF
CONVERGENCE AND FAVORED MID LEVEL SUPPORT IN CANADA. ANY OTHER
CHANGES TO FORECAST MINOR.
UPDATE ISSUED AT 633 PM CDT SUN JUL 21 2013
LINE OF DEEP CONVECTION EXTENDING FROM NEAR PILOT MOUND MB TO
RUGBY AND WEST OF BIS. BASED ON CURRENT TIMING ADJUSTED POPS
DELAYING HIGHER POPS ACROSS NW AND KEEPING SOUTHERN FA DRY LONGER.
NO OTHER CHANGES THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 303 PM CDT SUN JUL 21 2013
MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR
TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR
PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT
SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY.
CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN
AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM
THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW
POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S.
EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM
MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM
COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT
WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO.
INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY
CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS
IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER
TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS
BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE
MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA
WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET
ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY
OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR
PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF
CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME
STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR
WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH
AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO
OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE
FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING
TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE
CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF
OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE
COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD
KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE
SEVERE POTENTIAL WILL GO.
LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY
MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY
WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL
BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN JUL 21 2013
SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY
OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED
ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS.
WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS
PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING
BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT
THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW
ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE
REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1147 PM CDT SUN JUL 21 2013
CONFINED T MENTION TO BJI AND TVF FOR THE NEXT COUPLE HOURS. LONE
STRONG/SEVERE STORM WILL CONTINUE TO PROPAGATE SE INTO CENTRAL
PORTION OF FORECAST AREA. MVFR CIGS/VSBY IN STRONGER STORM OTHERWISE
VFR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...GODON
LONG TERM...GODON/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
121 AM EDT MON JUL 22 2013
.SYNOPSIS...
A WEAK STATIONARY FRONT ACROSS THE SOUTHERN OHIO VALLEY WILL
REMAIN IN PLACE INTO MONDAY EVENING BEFORE DISSIPATING. AN UPPER
LEVEL DISTURBANCE WILL TRACK EAST CROSSING THE REGION LATER MONDAY
NIGHT AND EARLY TUESDAY. DEEP MOISTURE IN ASSOCIATION WITH THESE
FEATURES WILL KEEP ROUNDS OF SHOWERS AND THUNDERSTORMS GOING EARLY
THIS WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1000 PM EDT SUNDAY...
FOLLOWING CLOSE TO THE HRRR WHICH HIGHLIGHTS MORE THREAT OF
SHOWERS FROM SE WV EAST NORTHEAST INTO THE SOUTHERN SHENANDOAH
VALLEY OVERNIGHT BEFORE DIMINISHING. KEPT ISOLATED TO NONE IN THE
SOUTH. NOT MUCH CHANGE IN THE REST OF THE FORECAST AS WE SHOULD
SEE PATCHY FOG WITH MOSTLY CLOUDY SKIES.
OVERNIGHT LOWS WILL REMAIN ON THE MILD SIDE...GENERALLY FALLING
INTO THE MID 60S TO LOW 70S.
EXPECT GREATER COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY FOR
MONDAY AS A STRONGER UPPER LEVEL DISTURBANCE APPROACHES FROM THE
WEST. ONCE AGAIN...THE GREATEST THREAT NORTH OF INTERSTATE 81 WILL
BE LOCALLY HEAVY RAIN...WITH RAINFALL RATES OF AN INCH OR MORE
OVER A FEW MINUTES TIME. AS SUCH...WILL AGAIN BE CONCERNED WITH
LOCALIZED FLASH FLOODING. WILL LEAVE THE DECISION OF THE TIMING
AND LOCATION OF A FLASH FLOOD WATCH TO THE OVERNIGHT
SHIFT...GIVING THEM AN OPPORTUNITY TO LOOK AT ANOTHER SET OF
SYNOPTIC WEATHER MODELS. SOUTH OF INTERSTATE 81...WILL ALSO SEE A
SLIGHTLY GREATER THREAT OF STRONG TO SEVERE THUNDERSTORMS DURING
THE AFTERNOON AND EVENING DUE TO STRONGER SURFACE HEATING. STUCK
PRETTY CLOSE TO MET GUIDANCE FOR AFTERNOON TEMPERATURES...WITH
HIGHS REACHING THE UPPER 70S AND LOW 80S WEST...AND REACHING TO
AROUND 90 ACROSS THE PIEDMONTS.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 340 PM EDT SUNDAY...
WELL DEFINED SHORT WAVE CROSSES THE FORECAST AREA MONDAY NIGHT AND
TUESDAY. THIS WILL KEEP A BETTER PROBABILITY OF PRECIPITATION
OVERNIGHT THAN JUST THE TYPICAL DIURNAL CYCLE OF THE PAST FEW DAYS.
UPPER TROF AMPLIFIES ENOUGH THAT THE FRONT WILL PUSH SOUTH OF THE
FORECAST AREA ON WEDNESDAY. AS THE FRONT COMES THROUGH ON WEDNESDAY
THE EXPECTING MORE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS IN
THE AFTERNOON AND EVENING. WITH THE PASSAGE OF THE SHORT WAVE...MID
LEVEL TEMPERATURES COOL SLIGHTLY WHICH WILL ENHANCE THE LAPSE RATES
AND INSTABILITY.
LITTLE CHANGE IN DAILY HIGH AND LOW TEMPERATURES AND IN MOISTURE OF
THE AIR MASS. STAYED CLOSE TO MODEL GUIDANCE FOR MAXIMUM AND MINIMUM
TEMPERATURES EACH DAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 1140 AM EDT SUNDAY...
NO CHANGE IN THE OVERALL PATTERN THROUGH THE EXTENDED PERIOD. MODELS
BRINGING STRONG ENOUGH SHORT WAVE THROUGH THE EASTERN UPPER TROF ON
THURSDAY TO PUSH A SURFACE FRONT INTO THE SOUTHEAST STATES. THIS
WOULD BRING WINDS AROUND TO THE NORTHWEST AND NORTH. MAY NOT
COMPLETELY ELIMINATE THE PROBABILITY OF PRECIPITATION FOR THE
FORECAST AREA...BUT CHANCES ON THURSDAY AND FRIDAY SHOULD BE LESS
THAN IN RECENT DAYS. SOME SIGNS IN THE MODELS OF ACTUAL DRIER AIR
REACHING THE FORECAST AREA. SUBTLE DROP IN 850 MB TEMPERATURES
BEHIND THE FRONT...OTHERWISE NEAR NORMAL FOR HIGHS AND LOWS THROUGH
DAY 7/SUNDAY.
SURFACE LOW PRESSURE OVER THE MISSISSIPPI VALLEY ON SATURDAY WILL
APPROACH THE REGION BY SUNDAY. WINDS WILL BE BACK AROUND TO THE
SOUTHWEST WITH DEEP MOISTURE RETURNING AHEAD OF THE LOW.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 1250 AM EDT MONDAY...
EARLIER SHOWERS HAVE ALL BUT FADED EXCEPT ACROSS THE GREENBRIER
VALLEY WHERE A CLUSTER REMAINS MAINLY JUST WEST OF KLWB. EXPECT
THIS PRECIP TO SLOWLY EXIT TO THE NORTH IN THE NEXT HOUR LEAVING
AREAS OF LOW CLOUDS AND FOG WHICH SHOULD DROP KLWB TO IFR/LIFR IN
THE NEXT COUPLE OF HOURS. ELSW LINGERING DEBRIS MID DECK MAY TEND
TO LIMIT FOG FORMATION INITIALLY BUT EXPECT ENOUGH THINNING
OVERNIGHT TO ALLOW AREAS OF DENSE FOG ESPCLY EAST WHERE EARLIER
MORE WIDESPREAD HEAVY RAINFALL OCCURRED. THUS STILL THINKING MVFR
WITH MORE IFR EAST AND AROUND KBCB...WITH POTENTIAL LOW CIGS AT
KBLF.
COVERAGE OF SHOWERS AND STORMS LOOKS BETTER MONDAY AND EVEN
THOUGH THIS IS LIKELY...KEPT VCTS IN THE TAFS AND PREDOMINAT
SHOWERS...AS MODELS STILL SHOWING AT LEAST SOME PERIODS OF LESS
COVERAGE MAINLY EAST OF THE BLUE RIDGE EARLY ON. MAIN CONCERNS
WITH THIS DISTURBANCE WILL AGAIN BE HEAVY RAIN...RESULTING IN
PERIODIC IFR CONDITIONS AT ALL AIRPORTS. A FEW SEVERE STORMS WILL
ALSO BE POSSIBLE...MORE SO FOR KDAN AND KLYH WHERE STRONGER
DAYTIME HEATING WILL ADD TO ATMOSPHERIC INSTABILITY DURING THE
AFTERNOON. SHOWERS MAY LINGER INTO MONDAY EVENING WITH THE ACTUAL
TROF AXIS CROSSING THE REGION DESPITE LOSS OF HEATING SO EXTENDING
SHRA MENTION AT MOST LOCATIONS PAST SUNSET.
MODELS CONTINUE TO DEPICT THE STALLED FRONT HOLDING JUST NORTH OF
THE AREA THROUGH EARLY TUESDAY...BEFORE LIFTING AS A LOW PRESSURE
SYSTEM MOVES ACROSS THE WESTERN GREAT LAKES. REGARDLESS...EXPECT
DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS TO PERSIST THROUGH THE
COMING WORKWEEK AS GULF MOISTURE REMAINS ABUNDANT ACROSS THE AREA.
ANOTHER COLD FRONT WILL APPROACH THE OHIO RIVER TOWARD THE END OF
THE WORKWEEK...BUT DO NOT SEE THE FRONT ADVANCING MUCH FURTHER
SOUTH THAN THAT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...NF/WP
SHORT TERM...AMS/RCS
LONG TERM...AMS
AVIATION...JH/NF/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
335 AM CDT MON JUL 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE
THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING.
LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN
MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE
OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG
THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN
NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING
SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON.
THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND
BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF
MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS
TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS
AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE
AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500
TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW
SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM
BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST
OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED
PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE
CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR
ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS.
CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS
AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE
MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN
CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800
MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO
DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS
AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE
CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON.
ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE
TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED
TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE
WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING
OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT
SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL
GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE
DAMAGING WINDS.
THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE
19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST
MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING
ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN
THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE
FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP
THIS AFTERNOON.
HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER
TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB
INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE
MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS
EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS
WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT
LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS.
OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR
WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 335 AM CDT MON JUL 22 2013
SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON
TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES.
NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS
FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE
LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND
80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY
OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND
CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG
DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL
WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL
FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK
RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF
THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION
LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW
ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE
AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF
ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE
WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE
STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY.
PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK
SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE
AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90
DURING THE DAY ON SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN JUL 21 2013
FOG/STRATUS DEVELOPMENT A CONCERN OVERNIGHT. BUFKIT SOUNDINGS
INDICATE A MOIST NEAR SFC LAYER //AIDED BY RAINFALL TODAY// UNDER AN
INVERSION NEAR 900 MB. T/TD SPREAD OF 3-7 DEGREES ALREADY AT 03Z
WITH CLEAR SKIES OVERHEAD. HOWEVER...THE SOUNDINGS KEEP WINDS
STIRRED JUST OFF THE SFC..10+ KTS BY 200 FT. THIS WOULD GENERALLY
FAVOR MORE OF A STRATUS THREAT THAN DENSE FOG. WILL STAY WITH THIS
TREND IN THE TAFS.
COLD FRONT SLATED TO SINK ACROSS THE AREA LATER FRIDAY
AFTERNOON/EVENING...WITH A SWITCH TO NORTHWEST WINDS NEAR/SHORTLY
AFTER 00Z. LOW LEVEL INVERSION WILL SERVE TO KEEP THE ATMOSPHERE
CAPPED FOR MUCH OF THE DAY...BUT THE FRONT SHOULD PROVIDE ENOUGH
FORCING TO FIRE A LINE OF SHRA/TS BETWEEN 19-21Z...WHICH WILL TRACK
ACROSS THE TAF SITES. COULD BE SOME STRONG/SEVERE STORMS. CONFIDENCE
INCREASING IN THIS SCENARIO AND WILL REFLECT THIS IN THE TAFS.
EXPECTING SOME ENHANCED GUSTINESS AROUND THE STRONGER STORMS. PCPN
WILL CLEAR WITH THE BOUNDARY...BUT CLOUDS COULD LINGER THROUGH THE
EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1159 PM CDT SUN JUL 21 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 330 PM CDT SUN JUL 21 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COUPLE
SHORTWAVES UPSTREAM...ONE OVER WESTERN WISCONSIN WHICH IS
RESPONSIBLE FOR THE CLUSTER OF SHOWERS AND STORMS MOVING OVER
CENTRAL WISCONSIN...AND ANOTHER OVER IOWA. MAINLY THE SOUTHERN
PORTION OF THE FORECAST AREA WILL BE IMPACTED WITH THESE STORMS FOR
THE REST OF THE AFTERNOON...BUT NO SEVERE WEATHER IS EXPECTED.
FURTHER UPSTREAM...THE NEXT SHORTWAVE IS PRODUCING STORMS OVER FAR
SOUTH-CENTRAL CANADA AND NORTHERN NORTH DAKOTA WHICH WILL ARRIVE
TOMORROW. PRECIP CHANCES FOR THE REST OF TODAY AND SEVERE WEATHER
CHANCES TOMORROW ARE THE MAIN FORECAST CONCERNS.
TONIGHT...SHORTWAVE IMPULSES MOVING EAST ACROSS THE REGION WILL TAKE UNTIL
MID TO LATE EVENING TO EXIT. AS A RESULT...POTENTIAL WILL BE THERE
FOR ISOLATED TO SCATTERED THUNDERSTORMS UNTIL THEN OVER THE SOUTHERN
FORECAST AREA...EVEN THOUGH THE MAIN CLUSTER WILL HAVE PROBABLY
EXITED BY THE START OF THE EVENING. PLENTY OF CLEARING OCCURRING
UPSTREAM OF THE SHORTWAVES...THOUGH MODELS DEPICT WEAK ISENTROPIC
ASCENT CONTINUING THROUGH THE NIGHT. AM THINKING WILL SEE A PERIOD
OF SUBSIDENCE BEHIND THE WAVE...WHICH COULD LEAD TO A SEVERAL HOURS
OF MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS. NOT SURE HOW LONG THIS
WILL LAST...BUT 850MB THETAE ADVECTION DOES RAMP UP LATE AHEAD OF
THE SHORTWAVE CURRENTLY MOVING INTO NORTHERN NORTH DAKOTA. NOT OUT
OF THE QUESTION THAT CONVECTION COULD APPROACH N-C WISCONSIN LATE
TONIGHT. SO WILL SHOW INCREASING CLOUDS AFTER MIDNIGHT ALONG WITH
SLIGHT CHANCE TO CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN. LOWS MAINLY IN THE MID 50S TO LOW 60S.
MONDAY...THE NORTH DAKOTA SHORTWAVE WILL MOVE ACROSS NORTHERN
WISCONSIN DURING THE MORNING. BOTH THE NAM AND GFS SHOW A DECENT
WIND SHIFT OCCURRING AT 700MB SO WOULD NOT BE SURPRISED TO SEE SOME
CONVECTION MOVE ACROSS THE NORTH. THEN A STRONG SHORTWAVE OVER
WESTERN ONTARIO WILL DRIVE A COLD FRONT ACROSS NORTHWEST WISCONSIN
DURING THE AFTERNOON. DEPENDING UPON IF PRECIP OCCURS OVER NORTHERN
WISCONSIN AND HOW MUCH DESTABILIZATION CAN OCCUR WITH AMPLE CLOUD
COVER...MODIFYING PROGGED SOUNDINGS NEAR RHINELANDER FOR AN 80F/64F
PARCEL YIELDS 1700 J/KG OF ML CAPE AT 21Z. WITH 0-6KM BULK SHEAR
VALUES OF 30-35KTS...POTENTIAL WILL BE THERE FOR SEVERE STORMS
TOMORROW AFTERNOON OVER N-C AND POSSIBLY CENTRAL WISCONSIN TOO. WARM
ADVECTION AHEAD OF THE FRONT WILL PUSH HIGHS TO THE UPPER 70S AND MID
80S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 330 PM CDT SUN JUL 21 2013
NOT MUCH CHANGE IN THE OVERALL FORECAST FOR THIS PERIOD AS
SHORTWAVE TROFS MOVE THROUGH MEAN TROF POSITION ACROSS GREAT
LAKES. LATEST GFS AND ECMWF IN GENERAL AGREEMENT THROUGH MOST OF
PERIOD ON STRENGTH AND TIMING OF SYSTEMS.
TEMPS WILL BE AOB NORMAL FOR MUCH OF WEEK...AFTER MONDAY. IN
FACT...HIGHS NEXT WEEKEND MAY STRUGGLE TO REACH 70 ACROSS PARTS OF
THE NORTH AS NW FLOW IS REINFORCED BEHIND LATE WEEK SYSTEM.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1159 PM CDT SUN JUL 21 2013
PATCHY IFR/MVFR CIGS WILL LINGER OVER THE REGION
OVERNIGHT DUE TO RETURN FLOW AHEAD OF A APPROACHING COLD FRONT.
AREAS OF FOG WILL ALSO DEVELOP WHERE CLEAR SKIES PREVAIL.
MORE MVFR CIGS AND VSBYS DUE TO SHOWERS AND STORMS LIKELY ALONG
THIS FRONT STARTING MONDAY AFTERNOON OVER NORTHWEST WISCONSIN
BEFORE REACHING SOUTHEAST WISCONSIN MONDAY NIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
724 AM EDT MON JUL 22 2013
.SYNOPSIS...
A STALLED FRONT SOUTH OF NEW ENGLAND WILL PUSH NORTH ACROSS THE
REGION LATE TONIGHT INTO TUESDAY BRINGING NUMEROUS SHOWERS AND
SCATTERED THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL POSSIBLE. A
COLD FRONT WILL SWEEP ACROSS NEW ENG WEDNESDAY FOLLOWED BY COOLER
AND LESS HUMID WEATHER THURSDAY AND FRIDAY. WARMER AIR RETURNS
FOR NEXT WEEKEND BEFORE A COLD FRONT NEXT SUN MAY BRING
ADDITIONAL SCATTERED SHOWERS/THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
SURFACE FRONTAL BOUNDARY REMAIN SOUTH OF THE REGION WHILE VERTICAL
WIND PROFILERS ARE EXHIBITING LIGHT SOUTHERLY FLOW ACROSS LONG
ISLAND WITH A MORE EASTERLY COMPONENT OVER THE TAUNTON WEATHER
FORECAST OFFICE. WHETHER THE QUASI-STATIONARY STORM OVER THE
SOUTHERN WATERS IS A SIGN OF THINGS TO COME...THERE IS SURELY
CONCERN OVER THE POTENTIAL FOR PERSISTENT HEAVY RAIN ALONG THE
SURFACE FRONTAL BOUNDARY AS IT SLOWLY LIFTS NORTH TODAY.
WAVERING CONFIDENCE WITH HOW THE TODAYS WEATHER IS GOING TO
SPECIFICALLY PLAY OUT. FEEL A BLEND OF THE SREF/NAM/ECMWF IS A
GOOD STARTING POINT. WRF-MODEL SOLUTIONS AND THE HRRR ARE VALUABLE
APPROXIMATIONS OF POTENTIAL SCENARIOS WHEN EVALUATING SIMULATED
RADAR REFLECTIVITY.
TWO AREAS OF CONCERN: TRAINING OF PERSISTENT RAIN AND EMBEDDED
HEAVIER SHOWERS / THUNDERSTORMS ALONG THE FRONTAL BOUNDARY...AND
THE POTENTIAL FOR BOUNDARY LAYER DESTABILIZATION ACROSS THE
INTERIOR. SO THERE COULD BE ISSUES ALONG THE SOUTH COAST ALONG
WITH INTERIOR SHOWERS.
ECHO THE PREVIOUS FORECASTERS THINKING...THERE IS ENOUGH MOISTURE
IN THE COLUMN FOR MORE CLOUDS THAN SUNSHINE AND MODELS ARE
GENERATING MARGINAL INSTABILITY TO SUPPORT SCATTERED SHOWERS AND
THUNDERSTORMS AS WEAK SHORTWAVE ENERGY APPROACHES FROM THE GREAT
LAKES. THUS THE BEST CHANCE FOR CONVECTION WILL BE ACROSS CENTRAL
AND WESTERN AREAS FURTHER REMOVED FROM MORE STABLE MARITIME AIR.
CAPES ARE FORECAST TO BE AOB 1000 J/KG WITH POOR MID LEVEL LAPSE
RATES SO SEVERE WEATHER IS NOT ANTICIPATED...BUT A HEAVY RAIN
THREAT WITH THE POTENTIAL FOR LOCALIZED FLOODING WILL EXIST.
EASTERLY FLOW DEVELOPS WHICH WILL RESULT IN COOLER TEMPS WITH
MAXES MOSTLY UPPER 70S TO LOWER 80S...BUT IT WILL BE HUMID WITH
DEWPOINTS FORECAST TO INCREASE TO NEAR 70.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MID LEVEL TROF ACROSS THE GT LAKES FORECAST TO MOVE EAST TOWARD
NEW ENGLAND LATE TONIGHT INTO TUE WITH MULTIPLE SHORTWAVES MOVING
THROUGH THE FLOW. THE SFC BOUNDARY TO THE S WILL BEGIN TO MOVE
BACK AS A WARM FRONT LATER TONIGHT BUT IT IS UNCERTAIN HOW FAR N
THIS BOUNDARY WILL GET ON TUE. WE DISCOUNTED THE GFS WHICH
APPEARS TOO AGGRESSIVE WITH PUSHING THE FRONT INTO N NEW ENG. WE
USED A BLEND OF NAM/ECMWF WHICH BRINGS IT INTO SNE ALTHOUGH THE
EXACT LOCATION IS UNCERTAIN.
WE EXPECT INCREASING COVERAGE OF SHOWERS/TSTMS LATE TONIGHT INTO
TUE AS THE SHORTWAVES MOVE INTO NEW ENG WITH RIGHT ENTRANCE REGION
OF UPPER JET PROVIDING EXTRA DYNAMICAL SUPPORT. PWATS INCREASE TO
GREATER THAN 2" SO PRIMARY THREAT WILL BE LOCALLY HEAVY RAINFALL.
LOCATION OF THE SFC BOUNDARY WILL DETERMINE WHERE AXIS OF HEAVIEST
RAINFALL SETS UP WHICH AT THIS TIME APPEARS TO BE NORTH AND WEST
OF THE I95 CORRIDOR...BUT THIS COULD CHANGE. SEVERE THREAT IS LOW
DUE TO ABUNDANT CLOUD COVER AND WEAK SHEAR. MAXES TUE WILL BE IN
THE UPPER 70S TO LOWER 80S AND CONTINUED QUITE HUMID AS
DEWPOINTS INCREASE INTO THE LOWER 70S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HEADLINES...
* WET WEATHER DIMINISHING INTO WEDNESDAY
* DRY AND SEASONABLE CONDITIONS PREVAIL FOR THE LATE WEEK
* SEVERE WEATHER POSSIBLE FOR SATURDAY AND AGAIN SUNDAY?
* DRY AND BELOW-SEASONABLE CONDITIONS HINTED FOR NEXT WEEK
*/OVERVIEW AND MODEL CONSENSUS...
SUITE OF FORECAST GUIDANCE FINALLY COMING INTO BETTER AGREEMENT
WHILE NO LONGER SUGGESTING ANOMALOUS DEEP NORTHERN STREAM TROUGHING
ACROSS THE EASTERN CONUS. FEEL AN EQUAL BLEND OF DETERMINISTIC
FORECAST GUIDANCE IS WELCOMED...BUT AM CAUTIOUS AS THIS IS ONLY THE
FIRST INSTANCE OVER THE PAST WEEK IN WHERE THE GUIDANCE HAS BECOME
WELL-ALIGNED. JUST YESTERDAY OUTCOMES WERE CONSIDERABLY DIFFERENT
ACROSS THE NORTHEASTERN CONUS. AM WANTING TO SEE MODEL CONSISTENCY
FOR THE NEXT COUPLE OF RUNS PRIOR TO JUMPING ON ANY ONE THOUGHT
PROCESS...SO AGREE WITH WPC/HPC IN UTILIZING ENSEMBLE MEANS AS
ELSEWHERE ACROSS THE CONUS...ESPECIALLY WITHIN THE SHORT-TERM...
PACIFIC DISTURBANCES MOVING THROUGH THE BROADER LONGWAVE FLOW ARE
STILL BEING HANDLED DIFFERENTLY BETWEEN FORECAST SOLUTIONS LENDING
TO CONFLICTING SURFACE OUTCOMES. NOTHING IS CONCRETE.
UPDATE: 22.0Z ECMWF HAS TRENDED A MORE ANOMALOUS NORTHERN STREAM
TROUGHING SOLUTION. FEEL THIS IS A CONSEQUENCE OF POOR HANDLING OF
PACIFIC DISTURBANCES AROUND THE DEEPER LOW OVER ONTARIO. WILL FOREGO
THE SOLUTION WITH THIS FORECAST AND MAINTAIN WITH THE 22.0Z GFS AND
21.12Z ECMWF CONSISTENCY.
*/DAY-TO-DAY DETAILS...
*/TUESDAY NIGHT INTO WEDNESDAY...
WEAK SURFACE LOW COUPLED TO THE RIGHT-REAR QUADRANT OF THE UPPER-
LEVEL JET AND DEEP-LAYER ASCENT LIFT NORTHEASTWARD /22.0Z NAM IS
SLOWEST WITH THIS OUTCOME/. WHILE A SURFACE TROUGH ATTENDANT TO THE
LOW LINGERS ACROSS SOUTHERN NEW ENGLAND...THIS WILL BE WASHED OUT AS
THE MAIN IMPULSE THROUGH THE BROAD TROUGH PATTERN PUSHES COOLER AND
DRIER AIR BEHIND A WELL-DEFINED SURFACE COLD FRONT THROUGH THE
NORTHEASTERN CONUS. THIS WILL PUSH THE DEEPER PWAT AXIS OFFSHORE
LIMITING THE HEAVY RAIN THREAT.
WILL DIMINISH CHANCE POPS NORTHWEST TO SOUTHEAST GRADUALLY THROUGH
THE PERIOD. NO MENTION OF HEAVY RAIN WILL BE MADE TO THE FORECAST.
LITTLE CONFIDENCE FOR THUNDERSTORMS WITH DRIER AIR BUILDING INTO THE
REGION AND LIKELY BROADER SUBSIDENCE BEHIND THE AFOREMENTIONED MAIN
IMPULSE THROUGH THE DAY WEDNESDAY. SOUTHWEST WINDS BACKING OUT OF
THE NORTH-NORTHWEST AND DIMINISHING WITH FRONTAL PASSAGE.
*/WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...
AN AMAZING ABOUT FACE IN THE FORECAST GUIDANCE WHICH JUST LAST NIGHT
WAS SUGGESTING CONTINUED RAIN CHANCES. WITH THIS FORECAST A SIMPLE
RULE APPLIES: BETWEEN TWO REGIONS OF RISING AIR THERE NEEDS TO BE A
BALANCE BETWEEN OF SINKING MOTIONS. WITH ENERGY ELONGATED ALONG AN
OFFSHORE STALLED FRONTAL BOUNDARY AGAINST THE BROADER ATLANTIC RIDGE
AND A STRONG IMPULSE ACROSS QUEBEC...THE NORTHEASTERN CONUS FINDS
ITSELF IN A FAVORABLE REGION OF SINKING DRIER AIR.
WITH BOTH THE 22.0Z GFS AND 21.12Z ECMWF NO LONGER EXHIBITING
ANOMALOUS DEEP NORTHERN STREAM TROUGHING...RATHER WELL UNIFIED IN
THE EVOLUTION OF AN OCCLUDED LOW PRESSURE CENTER OVER THE SOUTHERN
HUDSON BAY REGION...WILL BLEND THE SOLUTIONS AND KEEP THE FORECAST
PERIOD DRY. THE PREVAILING PERIOD OF BROAD HIGH PRESSURE WILL ALLOW
FOR LIGHT WINDS ACROSS THE REGION. WILL LIKELY SEE SUCCESSIVE DAYS
OF SEA-BREEZES ALONG THE SHORES THURSDAY AND FRIDAY. BROADER
TROUGHING ACROSS THE REGION WILL KEEP TEMPERATURES SEASONABLE.
SOME UNCERTAINTY ON FRIDAY...FALLING HEIGHTS WITH A WEAK TROUGH
ACROSS THE REGION SUGGESTED. IF MID- TO UPPER-LIFT IS MATERIALIZES
AND COLLOCATES WITH LOW-LEVEL CONVERGENCE ALONG SEA-BREEZES...IT IS
PLAUSIBLE TO SEE SOME SHOWERS. BOTH THE GFS AND ECMWF SUGGEST POOR
MID-LEVEL LAPSE RATES IN THE REGION OF THE LEFT-REAR QUAD OF THE
UPPER-LEVEL JET...SO THIS LESSENS CONFIDENCE OF SHOWER AND T-STORM
ACTIVITY.
*/SATURDAY INTO SUNDAY...
MAIN IMPULSE AND DEEP-LOW PUSH OUT OF THE SOUTHERN HUDSON BAY
REGION. ATTENDANT COLD FRONT SWEEPS THROUGH THE NORTHEASTERN CONUS
DURING THE TIMEFRAME...THOUGH THE TIMING IS SOMEWHAT UNCERTAIN.
NEVERTHELESS...CLIMATOLOGICALLY THE SYNOPTIC SETUP SUPPORTS THE
POTENTIAL FOR SEVERE WEATHER ACROSS THE NORTHEASTERN CONUS. IT IS
ENTIRELY PLAUSIBLE TO SEE SUCCESSIVE DAILY EPISODES...THE FIRST
ACROSS THE NY/PA INTO WESTERN NEW ENGLAND...THE SECOND OVER NEW
ENGLAND ITSELF.
A DAY 6/7 FORECAST...THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY.
HAVE MORE CONFIDENCE WITH THE 21.12Z ECMWF OUTCOMES. WILL GO WITH
CHANCE POPS FOR SHOWERS AND THUNDERSTORMS. WON/T SPECULATE AT THIS
TIME ABOUT SPECIFIC SEVERE WEATHER OUTCOMES...NOR HEAVY RAIN
IMPACTS...AWAITING LATER MODEL SOLUTIONS TO EVALUATE CONSISTENCY.
*/INTO NEXT WEEK...
CONSISTENCY BETWEEN THE 21.18Z AND 22.0Z GFS COUPLED WITH THE 21.12Z
ECMWF SUGGEST HIGH PRESSURE BUILDING SOUTHEASTWARD INTO SOUTHERN NEW
ENGLAND AS THE DEEP LOW OVER CANADA LIFTS NORTHEAST THROUGH QUEBEC.
COOL MID-LEVEL AIR WITH SURFACE NORTHWEST FLOW SUGGESTS CONDITIONS
BELOW SEASONABLE LEVELS WHILE REMAINING DRY.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
INCREASING AREAL COVERAGE OF -RA WITH EMBEDDED +RA/TSRA. WILL SEE
LOWERING CIGS TOWARDS EVENING...DETERIORATING INTO THE OVERNIGHT.
LIGHT AND VARIABLE WIND FLOW AS A FRONTAL BOUNDARY LIFTS THROUGH
THE REGION. UNCERTAIN ON EXACT SPECIFICS AND SUBSEQUENT TRENDS...
BUT CONFIDENT THAT CONDITIONS WILL DETERIORATE AS SHRA/TSRA BECOME
WIDESPREAD INTO TUESDAY.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. LOWER CIGS COULD
DEVELOP SOONER THAN FORECAST.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOWER CIGS COULD
DEVELOP SOONER THAN FORECAST.
OUTLOOK...TUESDAY NIGHT INTO FRIDAY NIGHT...
TUESDAY NIGHT INTO WEDNESDAY...HIGH CONFIDENCE.
SHRA AND POSSIBLE TSRA LINGERING. WILL SEE ANY MVFR/IFR CONDITIONS
GRADUALLY LIFTING. COLD FRONT SWEEPING THROUGH THE TERMINALS. WILL
SEE SOUTHWEST WINDS /POTENTIALLY GUSTY/ BACKING OUT OF THE NORTH-
NORTHWEST AND WEAKENING. ANY COASTAL FOG SHOULD BE SCOURED OUT.
WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE CONFIDENCE.
VFR WITH HIGH PRESSURE IN CONTROL. SEA-BREEZES ALONG THE SHORES.
PERHAPS A SLIGHT CHANCE FOR SHRA/TSRA ON FRIDAY...LOW CONFIDENCE.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TUESDAY.
LIGHT PRES GRADIENT WILL KEEP WINDS BELOW SMALL CRAFT CRITERIA
THROUGH THE PERIOD. SEAS WILL BE BELOW SCA AS WELL BUT COULD BUILD
TO 5 FT OVER THE SOUTHERN WATERS BY LATE TUE.
OUTLOOK...TUESDAY NIGHT INTO FRIDAY NIGHT...
TUESDAY NIGHT INTO WEDNESDAY...HIGH CONFIDENCE.
COLD FRONT TO SWEEP ACROSS THE WATERS WEDNESDAY ALONG AND AHEAD OF
WHICH SOUTHWEST WINDS WILL GUST UP TO AROUND 20 KTS. SHRA/TSRA ALSO
LINGERING WITH POSSIBLE COASTAL FOG IMPACTS. WILL SEE CONDITIONS
IMPROVE LATE AS WINDS BACK OUT OF THE NORTH-NORTHWEST AND WEAKEN.
DRIER AIR BUILDING INTO THE REGION SHOULD ALLOW ANY FOG CONDITIONS
TO LIFT. SEAS TO BEGIN TO SUBSIDE WITH LESSER FLOW.
WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE CONFIDENCE.
HIGH PRESSURE BUILDING INTO THE WATERS. WINDS BECOMING LIGHT. WAVE
HEIGHTS SHOULD DIMINISH EARLY IN THE PERIOD AND REMAIN BELOW 5 FEET
THROUGHOUT THE FORECAST. SEA-BREEZES WILL DEVELOP DURING THE DAY
ALONG THE IMMEDIATE SHORES.
&&
.TIDES/COASTAL FLOODING...
ASTRONOMICAL TIDES WILL BE ABNORMALLY HIGH DURING THE HIGH TIDE
CYLCE NEAR MIDNIGHT TONIGHT. BOS TIDE IS 12.1 FT WHICH IS ABOUT AS
HIGH AS IT EVER GETS. WITH LIGHT EASTERLY FLOW EXPECT ABOUT A 0.5
FT TIDAL DEPARTURE WHICH SHOULD BE ENOUGH TO PRODUCE SOME
SPLASHOVER ALONG THE MOST VULNERABLE LOCATIONS ACROSS E COASTAL
MA.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
613 AM EDT Mon Jul 22 2013
...UPDATED FOR AVIATION SECTION...
.NEAR TERM [TODAY]...
The large scale longwave pattern is highlighted by weak ridging over
Wrn Conus and a upper level trough amplifying from Great Lakes into
Lwr MS Valley. Several shortwaves were noted in water vapor imagery
moving across base of trough including one over NW AL. At the
surface, a ridge of high pressure extends from the Atlc WWD across
the FL Peninsula and Cntrl Gulf of Mexico. A weak and dissipating
trough was noted across the WRN forecast area. 24hr temp/dew point
comparisons indicate little change in airmass last 24 hrs. Latest
radar pix shows noticeably less convection developing over the Gulf
waters than forecast. Still, HRRR and WRF show marine convection
moving onshore aft 10z from Panhandle waters reaching FL/AL border
by 14z. Still have updated 06z-12z and 12z-18z Grids to lower POPS
especially over waters and coasts and will monitor in case another
update is needed.
During the rest of today, progressive WSW steering flow as
unseasonably amplified upper trough digs SEWD into TN Valley and
deepens increasing tropical moisture plume, aided by AL shortwave
moving ESE provides additional lift. Surface ridge remains to our S
locally yielding SW flow. PWATs across the region from JAX west to
Dothan and beyond in excess of 2 inches this aftn. This will combine
with seabreeze/mesoscale outflows clashes from leftover boundaries
from surface trough for sct/numerous showers and thunderstorms with
heavy rain and gusty winds later today. As reflected in CAM and
other models, highest POPs over the NW zones closest to the upper
energy. Will go with 40-80% SE-NW POP gradient. RAP13 soundings show
uni-directional very moist profiles which favor good rain producers
and given recent rains, aggravate chances of at least nuisance
flooding again today. CAM QPF/flood tools shows Panhandle as best
bet with 1-2 inches avg STP. Although Shear unimpressive, model aftn
CAPE around 2400 J/KG across SE AL. Add presence of shortwave plus
any boundary clashes this favors at least strong storms to isold
severe storms with best bet SE AL/ adjacent GA/FL 21z-00z. This,
along with max temps will be partly dependent on amount of morning
cloudiness and where drier air sets making max temp forecast a
little tricky. Inland Highs generally 88 to 90.
&&
.SHORT TERM [Tonight through Wednesday]...
The pattern will transition to more of a northwest flow aloft
through the short term as the upper level trough axis moves east
of the area. A series of shortwaves is expected to move through
the base of the trough and aid in convective development over the
forecast area (PoPs 40-60% during the day). The northwest flow
aloft will also aid in advecting steeper than normal mid-level
lapse rates into the area by Tuesday into Wednesday, which may
increase the threat of isolated, pulse severe storms. These would
be most likely over the northern and western portions of the area.
The 22/00z GFS forecasts 700-500 mb lapse rates between 6-7 C/km,
which is 1-1.5 C/km above climo for this time of year.
&&
.LONG TERM [Wednesday Night through Sunday]...
The upper flow across the CONUS will be dominated by an eastern
trough and western ridge. Through most of the extended period, the
upper trough axis is forecast to be just east of the CWA, with
northwest flow aloft. While this flow is typically drier across
the region, the presence of a nearly stationary trough across the
northern half of the area will offset this to some extent. With
this in mind, will generally keep the PoPs at or below 50 percent
through the extended, especially for Thursday into the weekend.
With the slightly lower rain chances than the past several days,
expect high temperatures to creep back into the lower to mid 90s
as well.
&&
.MARINE...
With a persistent trough to the north and high pressure to the
south, winds over the marine area will be primarily out of the
southwest to west-southwest this week between 10 and 15 knots.
&&
.AVIATION...[Through 12Z Tuesday]
Although locales except DHN and TLH remain VFR at 10z, HRRR show
showers and thunderstorms developing at our western terminals
spreading E/NE reaching the FL/AL border thru 14z. Therefore
decided to include MVFR CIGS 12-14z at above sites. After morning
showers and thunderstorms diminish, there will likely be a break,
and then another round in the afternoon with conditions very
similar to what we saw on Sun with MVFR CIGS/VSBYS and gusty winds
in any heavy rain or strong storms. After 00z VFR conditions
return but after 07z, MVFR CIGS and possibly VSBYS especially
where any residual moister remains form earlier storms. Brief IFR
CIGS and MVFR VSBYS also possible near sunrise.
&&
.FIRE WEATHER...
Red flag conditions are not expected for the next several days.
&&
.HYDROLOGY...
A few rivers still remain at or near flood stage, including the
Aucilla and Econfina rivers. The Steinhatchee river is also out of
its banks south of US 19 with minor flooding expected downstream
of the gage for the next day or two. Scattered showers and storms
are expected through much of this week, but should not be
sufficient to produce widespread flooding. However, localized
areas of heavy rain are likely and could cause some urban and
small stream flooding on occasion.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 89 74 92 74 93 / 60 50 60 50 50
Panama City 86 76 88 76 88 / 60 50 60 40 50
Dothan 88 73 92 73 91 / 70 40 60 50 50
Albany 89 73 92 74 92 / 70 40 60 40 50
Valdosta 89 73 92 74 94 / 70 40 60 40 50
Cross City 89 73 88 73 90 / 50 40 60 40 50
Apalachicola 86 77 88 77 90 / 60 50 60 40 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Risk for Rip Currents for FLZ108-112-114.
GA...None.
AL...None.
GM...None.
&&
$$
Near Term/Aviation/Fire Wx...Block
Short Term/Marine/Hydrology...DVD
Long Term...Camp
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
713 AM EDT MON JUL 22 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL PREVAIL
ALONG THE EAST COAST THROUGH MID WEEK. A WEAKENING COLD FRONT WILL
APPROACH FROM THE NORTHWEST LATE WEDNESDAY THROUGH THURSDAY...
STALLING NEAR THE AREA INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MADE A FEW CHANGES WITH THE EARLY MORNING UPDATE.
1. LOWERED POPS IN THE CHARLESTON TRI COUNTY AREA TO 40 PERCENT
AND INCREASED POPS TO 70 PERCENT OVER PORTIONS OF LONG...MCINTOSH
AND LIBERTY COUNTIES PER LATEST RUNS OF HIGH RESOLUTION MODELS.
BOTH THE RAP AND H3R NOW FOCUS MOST OF THE CONVECTION SOUTH OF
I-16 THIS AFTERNOON...ESPECIALLY NEAR THE ALTAMAHA RIVER.
2. ADJUSTED SKY COVER PER GOING SATELLITE TRENDS. IT NOW APPEARS A
GOOD PORTION OF THE AREA WILL INITIALIZE WITH MOSTLY SUNNY SKIES
THIS MORNING...ESPECIALLY IN THE BEAUFORT-SAVANNAH-LUDOWICI
CORRIDOR.
3. RAISED HIGH TEMPERATURES BY 1-2 DEGREES FOR MOST AREAS SINCE A
GOOD BIT OF SUN WILL OCCUR THIS MORNING AND TEMPERATURES ARE
STARTING OUT A TAD HIGHER THAN EXPECTED EARLIER THIS MORNING.
SUBTLE CHANGES ARE ONGOING IN THE ATMOSPHERE THIS MORNING WHICH WILL
HAVE SOME IMPACTS ON THE EVENTUAL CONVECTIVE PATTERN TODAY. THE
REGION WILL REMAIN IN THE FAMILIAR UPPER AIR CONFIGURATION
FEATURING DEEP LAYERED HIGH PRESSURE CENTERED WELL OFFSHORE AND A
TROUGH OF LOW PRESSURE LINGERING ACROSS THE SOUTHERN MISSISSIPPI
VALLEY. THE UPPER TROUGH IS FORECAST TO PROPAGATE SLOWLY EAST WITH
A LOBE OF VORTICITY EJECTING EAST ACROSS THE MIDLANDS AND UPSTATE
DURING PEAK HEATING. THIS FEATURE COUPLED WITH HIGH PWATS AND
DAYTIME HEATING WILL YIELD A DECENT AMOUNT OF SHOWERS/TSTMS ACROSS
THE MIDLANDS AND POSSIBLY THE CSRA...ESPECIALLY THIS AFTERNOON.
FARTHER SOUTH...MODELS SHOW A POCKET OF RELATIVELY LOWER MID-
LEVEL THETA AIR MOVING ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA AND
SOUTHEAST GEORGIA THIS AFTERNOON. MORNING WATER VAPOR IMAGERY AND
GOES SOUNDINGS ACROSS ALABAMA CONFIRM THIS POCKET OF DRY AIR
EXISTS SO HAVE NO REASON TO BOUT ITS EXISTENCE. THIS LOWER THETA
POCKET WILL LIKELY LIMIT THE COVERAGE OF SHOWER/TSTMS A BIT
TODAY...ESPECIALLY WHEN COMPARED TO PREVIOUS DAYS. IN FACT...SOME
OF THE GLOBAL MODELS SHOW VERY LITTLE IN THE WAY OF TSTM ACTIVITY
FIRING TODAY. THE HIGHER RESOLUTION MODELS ARE LIKELY MORE
REALISTIC DEPICTING CONVECTIVE CLUSTERS PROPAGATING IN FROM THE
SOUTHWEST LATER THIS AFTERNOON AND AFFECTING SOUTHEAST GEORGIA OR
MOVING IN FROM THE EASTERN MIDLANDS BY THIS EVENING AND IMPACTING
SOUTHERN SOUTH CAROLINA. PWATS ARE FORECAST TO LOWER BELOW 2
INCHES LATER TODAY...BUT LOCALIZED FLOODING WILL REMAIN A CONCERN.
OPTED TO STAY ON THE LOWER SIDE OF THE GUIDANCE ENVELOP FOR HIGH
TEMPERATURES AS EXTENSIVE CLOUD COVER AND SOME CONVECTION WILL
LIKELY LIMIT TEMPERATURES SOMEWHAT. HIGHS WILL RANGE FROM THE
UPPER 80S INLAND TO THE MID 80S AT THE COAST. IF CLOUDS THIN MORE
THAN EXPECTED...HIGHS COULD SOAR INTO THE LOWER 90S AS SUGGESTED
BY SOME ENSEMBLE MEMBERS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...CONVECTION WILL GRADUALLY DISSIPATE THIS EVENING WITH
DRY CONDITIONS PREVAILING OVERNIGHT. IT WILL REMAIN MOSTLY CLOUDY
WITH LOTS OF DEBRIS CLOUDINESS IN PLACE. LOWS WILL RANGE FROM THE
LOWER 70S INLAND TO THE MID-UPPER 70S AT THE COAST.
TUESDAY AND WEDNESDAY...AN UPPER LEVEL TROUGH WILL AMPLIFY ALONG THE
EAST COAST INTO THE MID WEEK PERIOD...WITH VARIOUS SHORTWAVES
SHIFTING INTO THE REGION WITHIN WEST/NORTHWEST MID AND UPPER LEVEL
FLOW. A WEAKENING COLD FRONT WILL ALSO BE APPROACHING FROM THE
NORTHWEST AND SLIPPING TOWARD THE FORECAST AREA BY LATE
WEDNESDAY...EMBEDDED WITHIN THE AXIS OF A SURFACE TROUGH DRIFTING
TOWARD THE COASTLINE.
CONVECTIVE COVERAGE...ALONG WITH THE POTENTIAL FOR HEAVY RAIN
AND/OR SEVERE WEATHER...APPEARS HIGHLY DEPENDENT ON THE TIMING AND
STRENGTH OF THE SERIES OF SHORTWAVES IMPACTING THE SOUTHEAST STATES
THROUGH THE PERIOD. NUMERICAL MODEL SOLUTIONS SHOW NOTABLE
VARIABILITY IN THEIR DEPICTION OF THIS ENERGY ALOFT...INCLUDING
AREAS OF NEGATIVE VORTICITY ADVECTION THAT COULD LIMIT COVERAGE AT
TIMES. DUE TO THIS UNCERTAINTY...HAVE LEANED TOWARD MORE
CONSERVATIVE POPS TUESDAY AND WEDNESDAY. WILL CONTINUE TO
HIGHLIGHT THE AFTERNOON AND EARLY EVENING PERIODS FOR BEST
COVERAGE OVER LAND...WITH POPS GENERALLY PEAKING IN THE 30 TO 40
PERCENT RANGE. SHOWERS/THUNDERSTORMS SHOULD DIMINISH ACROSS LAND
AREAS OVERNIGHT...WHILE THE MARINE ZONES EXPERIENCE AN INCREASE IN
ACTIVITY THROUGH THE EARLY MORNING HOURS.
PRECIPITABLE WATER WILL FALL BELOW 2 INCHES AND RANGE WITHIN MORE
SEASONAL VALUES FOR LATE JULY. HEAVY RAIN POTENTIAL WILL BE
REDUCED SLIGHTLY AS A RESULT...YET THE SUBSEQUENTLY DRIER MID
LEVEL AIR AND INCREASE IN LAPSE RATES SUGGEST A HIGHER POTENTIAL
FOR THE STRONGEST THUNDERSTORMS TO PRODUCE DOWNBURST WINDS.
ALTHOUGH ORGANIZED SEVERE WEATHER IS STILL NOT EXPECTED AT THIS
TIME...THERE IS A SMALL RISK FOR ISOLATED STORMS ENHANCED BY
MESOSCALE BOUNDARY INTERACTIONS TO INTENSIFY TO SEVERE
THRESHOLDS...WITH THE MAIN HAZARD BEING DAMAGING WIND GUSTS.
THURSDAY...THE WEAKENING COLD FRONT WILL CONTINUE TO SLIP
SOUTHEAST INTO THE FORECAST AREA...AS A DECENT WAVE OF LOW
PRESSURE DEVELOPS ALONG THE BOUNDARY AND DRIFTS ACROSS THE
SOUTHEAST COAST. THE AXIS OF THE STRONGEST IN THE SERIES OF
SHORTWAVES WILL BE JUST UPSTREAM BY SUNSET...PROVIDING ADDITIONAL
FORCING FOR ASCENT ACROSS THE REGION. DEEP MOISTURE WILL SURGE IN
RESPONSE TO BOTH THE UPPER LEVEL ENERGY AND LOW LEVEL CONVERGENCE
ALONG THE LINGERING FRONT. THE BEST CONVECTIVE COVERAGE OF THE SHORT
TERM PERIOD COULD OCCUR THURSDAY AFTERNOON AS A RESULT. HEAVY RAIN
COULD AGAIN BECOME A CONCERN CONSIDERING RISING PRECIPITABLE WATER
VALUES.
EXPECT LITTLE DAY TO DAY CHANGE IN TEMPERATURES THROUGH MID TO
LATE WEEK. HAVE INDICATED HIGHS REACHING THE LOWER 90S EACH
AFTERNOON AWAY FROM THE LOCALLY COOLER COASTLINE. LOW TEMPERATURES
WILL GENERALLY FALL INTO THE LOW TO MID 70S INLAND.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE MAIN SHORTWAVE TROUGH WILL SHIFT INTO THE ATLANTIC LATE
THURSDAY INTO FRIDAY...WITH A LESS AMPLIFIED UPPER LEVEL PATTERN
PREVAILING THROUGH AT LEAST SATURDAY. THE LINGERING COLD FRONT
WILL STALL AND EVENTUALLY DISSIPATE OVER THE SOUTHEAST
STATES...WHILE UPPER RIDGING BRIEFLY ATTEMPTS TO BUILD BACK INTO
THE REGION FROM THE SOUTH. WILL INDICATE MORE SEASONAL PRECIPITATION
COVERAGE FRIDAY AND SATURDAY...WITH ISOLATED TO SCATTERED
SHOWER/THUNDERSTORM ACTIVITY FOCUSED ALONG AND INLAND OF THE
SEABREEZE EACH AFTERNOON/EARLY EVENING. THERE IS RATHER
SIGNIFICANT DISAGREEMENT BETWEEN MEDIUM RANGE MODELS REGARDING THE
STRENGTH OF ANOTHER UPPER TROUGH RAPIDLY MOVING INTO THE REGION
SUNDAY AND MONDAY. PREFER TO MAINTAIN SOMEWHAT GENERIC RAIN
CHANCES PEAKING IN THE 30 PERCENT RANGE EARLY NEXT WEEK UNTIL
BETTER MODEL CONSISTENCY IS EVIDENT. HIGH TEMPERATURES WILL REACH
THE LOWER 90S AWAY FROM THE COASTLINE EACH AFTERNOON.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
KCHS...THE EASTERN EDGE OF A LOW CLOUD BANK HAS BRUSHED TERMINAL.
SATELLITE DATA AND RAP SOUNDINGS SUGGEST HIGH END IFR/LOW END MVFR
CIGS WILL LINGER THROUGH ABOUT 14Z THEN RETURN TO VFR. BEST TSTM
CHANCES LOOK TO REMAIN WELL SOUTH OF KCHS TODAY...ALTHOUGH AN
ISOLATED TSTM COULD STILL OCCUR. WILL KEEP ALL MENTION OF TSRA OUT
OF THE KCHS TAF FOR NOW.
KSAV...LOW CLOUDS LOOK TO REMAIN WEST OF THE TERMINAL THIS
MORNING. HIGH RESOLUTION MODEL GUIDANCE SUGGEST TSTMS WILL MOVE IN
FROM THE SOUTHWEST LATER THIS AFTERNOON AND POSSIBLY AFFECT THE
TERMINAL. TIMING/COVERAGE IS STILL A BIT UNCERTAIN THIS FAR OUT.
WILL CARRY A TEMPO GROUP FROM 20-23Z FOR 4SM -TSRA BR BKN040CB TO
COVER FOR NOW. FURTHER REFINEMENTS WILL BE NEEDED AS THE DAY
PROGRESSES. SHOWERS/TSTMS SHOULD QUICKLY DISSIPATE THIS EVENING
THUS ENDING THE RISK FOR TSTM IMPACTS.
EXTENDED AVIATION OUTLOOK...LITTLE CHANGE IN THE PATTERN THROUGH
THURSDAY...WITH MAINLY DIURNAL CONVECTION AND THE CHANCE FOR LATE
NIGHT/EARLY MORNING STRATUS. THIS WILL RESULT IN PERIODIC FLIGHT
RESTRICTIONS THROUGH THE PERIOD.
&&
.MARINE...
TODAY AND TONIGHT...SOMEWHAT ELEVATED WINDS WILL REMAIN IN PLACE
TODAY WITH SPEEDS GENERALLY 15-20 KT...EXCEPT CLOSER TO 15 KT IN
THE CHARLESTON HARBOR. SEAS WILL RANGE FROM 2-4 FT NEARSHORE
WATERS AND 4-5 FT OFFSHORE WATERS. ATTM IT APPEARS BOTH WINDS AND
SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. SIMILAR
CONDITIONS ARE EXPECTED TONIGHT.
TUESDAY AND WEDNESDAY...THE COASTAL WATERS WILL REMAIN BETWEEN
THE SUB-TROPICAL ATLANTIC RIDGE TO THE SOUTH/SOUTHEAST...WHILE A
PERSISTENT TROUGH OF LOW PRESSURE LINGERS INLAND. THE PRESSURE
GRADIENT WILL BE UNSEASONABLY ENHANCED AS A RESULT...SUPPORTING
WIND SPEEDS ABOVE NORMAL FOR LATE JULY. EXPECT WINDS TO PEAK AT 15
TO 20 KT THROUGH THE PERIOD...WITH OCCASIONAL GUSTS UP TO 25 KT.
SMALL CRAFT ADVISORIES DO NOT APPEAR NECESSARY AT THIS TIME DUE TO
THE INFREQUENCY OF HIGHER GUSTS. DIRECTIONS WILL BE MAINLY
SOUTHWEST...VEERING A LITTLE AT NIGHT AND BACKING SOME DURING THE
DAY WITHIN SEABREEZE CIRCULATIONS. SEAS WILL BE HELD UNDER 5 FT.
MARINERS ARE ADVISED THAT ISOLATED SHOWERS AND THUNDERSTORMS
COULD BECOME STRONG...WITH FREQUENT LIGHTNING AND HEAVY RAIN.
ISOLATED STORMS COULD ALSO PRODUCE WIND GUSTS IN EXCESS OF 35
KT...AND SPECIAL MARINE WARNINGS MAY BECOME NECESSARY. CHECK
NATIONAL WEATHER SERVICE FORECASTS AND NOAA WEATHER RADIO ALL
HAZARDS BEFORE AND DURING ANY NAVIGATION INTO THE COASTAL WATERS.
THURSDAY AND FRIDAY...THE PRESSURE GRADIENT WILL WEAKEN
CONSIDERABLY LATE IN THE WEEK...AS THE INLAND TROUGH DRIFTS TOWARD
THE COAST AND THE COLD FRONT STALLS INLAND. LIGHT WINDS COULD
ACTUALLY BECOME VARIABLE AT TIMES...GENERALLY CAPPED NO HIGHER
THAN 10 KT. OUTSIDE OF ANY CONVECTION...WINDS AND SEAS WILL BE
WELL BELOW ANY SMALL CRAFT CONDITIONS.
&&
.TIDES/COASTAL FLOODING...
THE PERIGEAN SPRING TIDES WILL PERSIST TODAY SO ONLY SMALL
POSITIVE TIDAL DEPARTURES MAY PRODUCE MINOR COASTAL FLOODING.
SHOULD ANY SHALLOW SALT WATER COASTAL FLOODING OCCUR THE MOST
LIKELY AREAS ARE CHARLESTON AND COASTAL COLLETON COUNTIES DURING
THE EVENING HIGH TIDES THROUGH WEDNESDAY. IT IS IN THESE AREAS
WHERE THE SMALLEST TIDAL DEPARTURES ARE REQUIRED FOR THE ISSUANCE
OF AN ADVISORY. WE HAVE MAINTAINED MENTION OF THIS POTENTIAL IN
THE HAZARDOUS WEATHER OUTLOOK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/WMS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
625 AM EDT MON JUL 22 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL PREVAIL
ALONG THE EAST COAST THROUGH MID WEEK. A WEAKENING COLD FRONT WILL
APPROACH FROM THE NORTHWEST LATE WEDNESDAY THROUGH THURSDAY...
STALLING NEAR THE AREA INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MADE A FEW CHANGES WITH THE EARLY MORNING UPDATE.
1. LOWERED POPS IN THE CHARLESTON TRI COUNTY AREA TO 40 PERCENT
AND INCREASED POPS TO 70 PERCENT OVER PORTIONS OF LONG...MCINTOSH
AND LIBERTY COUNTIES PER LATEST RUNS OF HIGH RESOLUTION MODELS.
BOTH THE RAP AND H3R NOW FOCUS MOST OF THE CONVECTION SOUTH OF
I-16 THIS AFTERNOON...ESPECIALLY NEAR THE ALTAMAHA RIVER.
2. ADJUSTED SKY COVER PER GOING SATELLITE TRENDS. IT NOW APPEARS A
GOOD PORTION OF THE AREA WILL INITIALIZE WITH MOSTLY SUNNY SKIES
THIS MORNING...ESPECIALLY IN THE BEAUFORT-SAVANNAH-LUDOWICI
CORRIDOR.
3. RAISED HIGH TEMPERATURES BY 1-2 DEGREES FOR MOST AREAS SINCE A
GOOD BIT OF SUN WILL OCCUR THIS MORNING AND TEMPERATURES ARE
STARTING OUT A TAD HIGHER THAN EXPECTED EARLIER THIS MORNING.
SUBTLE CHANGES ARE ONGOING IN THE ATMOSPHERE THIS MORNING WHICH WILL
HAVE SOME IMPACTS ON THE EVENTUAL CONVECTIVE PATTERN TODAY. THE
REGION WILL REMAIN IN THE FAMILIAR UPPER AIR CONFIGURATION
FEATURING DEEP LAYERED HIGH PRESSURE CENTERED WELL OFFSHORE AND A
TROUGH OF LOW PRESSURE LINGERING ACROSS THE SOUTHERN MISSISSIPPI
VALLEY. THE UPPER TROUGH IS FORECAST TO PROPAGATE SLOWLY EAST WITH
A LOBE OF VORTICITY EJECTING EAST ACROSS THE MIDLANDS AND UPSTATE
DURING PEAK HEATING. THIS FEATURE COUPLED WITH HIGH PWATS AND
DAYTIME HEATING WILL YIELD A DECENT AMOUNT OF SHOWERS/TSTMS ACROSS
THE MIDLANDS AND POSSIBLY THE CSRA...ESPECIALLY THIS AFTERNOON.
FARTHER SOUTH...MODELS SHOW A POCKET OF RELATIVELY LOWER MID-
LEVEL THETA AIR MOVING ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA AND
SOUTHEAST GEORGIA THIS AFTERNOON. MORNING WATER VAPOR IMAGERY AND
GOES SOUNDINGS ACROSS ALABAMA CONFIRM THIS POCKET OF DRY AIR
EXISTS SO HAVE NO REASON TO BOUT ITS EXISTENCE. THIS LOWER THETA
POCKET WILL LIKELY LIMIT THE COVERAGE OF SHOWER/TSTMS A BIT
TODAY...ESPECIALLY WHEN COMPARED TO PREVIOUS DAYS. IN FACT...SOME
OF THE GLOBAL MODELS SHOW VERY LITTLE IN THE WAY OF TSTM ACTIVITY
FIRING TODAY. THE HIGHER RESOLUTION MODELS ARE LIKELY MORE
REALISTIC DEPICTING CONVECTIVE CLUSTERS PROPAGATING IN FROM THE
SOUTHWEST LATER THIS AFTERNOON AND AFFECTING SOUTHEAST GEORGIA OR
MOVING IN FROM THE EASTERN MIDLANDS BY THIS EVENING AND IMPACTING
SOUTHERN SOUTH CAROLINA. PWATS ARE FORECAST TO LOWER BELOW 2
INCHES LATER TODAY...BUT LOCALIZED FLOODING WILL REMAIN A CONCERN.
OPTED TO STAY ON THE LOWER SIDE OF THE GUIDANCE ENVELOP FOR HIGH
TEMPERATURES AS EXTENSIVE CLOUD COVER AND SOME CONVECTION WILL
LIKELY LIMIT TEMPERATURES SOMEWHAT. HIGHS WILL RANGE FROM THE
UPPER 80S INLAND TO THE MID 80S AT THE COAST. IF CLOUDS THIN MORE
THAN EXPECTED...HIGHS COULD SOAR INTO THE LOWER 90S AS SUGGESTED
BY SOME ENSEMBLE MEMBERS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...CONVECTION WILL GRADUALLY DISSIPATE THIS EVENING WITH
DRY CONDITIONS PREVAILING OVERNIGHT. IT WILL REMAIN MOSTLY CLOUDY
WITH LOTS OF DEBRIS CLOUDINESS IN PLACE. LOWS WILL RANGE FROM THE
LOWER 70S INLAND TO THE MID-UPPER 70S AT THE COAST.
TUESDAY AND WEDNESDAY...AN UPPER LEVEL TROUGH WILL AMPLIFY ALONG THE
EAST COAST INTO THE MID WEEK PERIOD...WITH VARIOUS SHORTWAVES
SHIFTING INTO THE REGION WITHIN WEST/NORTHWEST MID AND UPPER LEVEL
FLOW. A WEAKENING COLD FRONT WILL ALSO BE APPROACHING FROM THE
NORTHWEST AND SLIPPING TOWARD THE FORECAST AREA BY LATE
WEDNESDAY...EMBEDDED WITHIN THE AXIS OF A SURFACE TROUGH DRIFTING
TOWARD THE COASTLINE.
CONVECTIVE COVERAGE...ALONG WITH THE POTENTIAL FOR HEAVY RAIN
AND/OR SEVERE WEATHER...APPEARS HIGHLY DEPENDENT ON THE TIMING AND
STRENGTH OF THE SERIES OF SHORTWAVES IMPACTING THE SOUTHEAST STATES
THROUGH THE PERIOD. NUMERICAL MODEL SOLUTIONS SHOW NOTABLE
VARIABILITY IN THEIR DEPICTION OF THIS ENERGY ALOFT...INCLUDING
AREAS OF NEGATIVE VORTICITY ADVECTION THAT COULD LIMIT COVERAGE AT
TIMES. DUE TO THIS UNCERTAINTY...HAVE LEANED TOWARD MORE
CONSERVATIVE POPS TUESDAY AND WEDNESDAY. WILL CONTINUE TO
HIGHLIGHT THE AFTERNOON AND EARLY EVENING PERIODS FOR BEST
COVERAGE OVER LAND...WITH POPS GENERALLY PEAKING IN THE 30 TO 40
PERCENT RANGE. SHOWERS/THUNDERSTORMS SHOULD DIMINISH ACROSS LAND
AREAS OVERNIGHT...WHILE THE MARINE ZONES EXPERIENCE AN INCREASE IN
ACTIVITY THROUGH THE EARLY MORNING HOURS.
PRECIPITABLE WATER WILL FALL BELOW 2 INCHES AND RANGE WITHIN MORE
SEASONAL VALUES FOR LATE JULY. HEAVY RAIN POTENTIAL WILL BE
REDUCED SLIGHTLY AS A RESULT...YET THE SUBSEQUENTLY DRIER MID
LEVEL AIR AND INCREASE IN LAPSE RATES SUGGEST A HIGHER POTENTIAL
FOR THE STRONGEST THUNDERSTORMS TO PRODUCE DOWNBURST WINDS.
ALTHOUGH ORGANIZED SEVERE WEATHER IS STILL NOT EXPECTED AT THIS
TIME...THERE IS A SMALL RISK FOR ISOLATED STORMS ENHANCED BY
MESOSCALE BOUNDARY INTERACTIONS TO INTENSIFY TO SEVERE
THRESHOLDS...WITH THE MAIN HAZARD BEING DAMAGING WIND GUSTS.
THURSDAY...THE WEAKENING COLD FRONT WILL CONTINUE TO SLIP
SOUTHEAST INTO THE FORECAST AREA...AS A DECENT WAVE OF LOW
PRESSURE DEVELOPS ALONG THE BOUNDARY AND DRIFTS ACROSS THE
SOUTHEAST COAST. THE AXIS OF THE STRONGEST IN THE SERIES OF
SHORTWAVES WILL BE JUST UPSTREAM BY SUNSET...PROVIDING ADDITIONAL
FORCING FOR ASCENT ACROSS THE REGION. DEEP MOISTURE WILL SURGE IN
RESPONSE TO BOTH THE UPPER LEVEL ENERGY AND LOW LEVEL CONVERGENCE
ALONG THE LINGERING FRONT. THE BEST CONVECTIVE COVERAGE OF THE SHORT
TERM PERIOD COULD OCCUR THURSDAY AFTERNOON AS A RESULT. HEAVY RAIN
COULD AGAIN BECOME A CONCERN CONSIDERING RISING PRECIPITABLE WATER
VALUES.
EXPECT LITTLE DAY TO DAY CHANGE IN TEMPERATURES THROUGH MID TO
LATE WEEK. HAVE INDICATED HIGHS REACHING THE LOWER 90S EACH
AFTERNOON AWAY FROM THE LOCALLY COOLER COASTLINE. LOW TEMPERATURES
WILL GENERALLY FALL INTO THE LOW TO MID 70S INLAND.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE MAIN SHORTWAVE TROUGH WILL SHIFT INTO THE ATLANTIC LATE
THURSDAY INTO FRIDAY...WITH A LESS AMPLIFIED UPPER LEVEL PATTERN
PREVAILING THROUGH AT LEAST SATURDAY. THE LINGERING COLD FRONT
WILL STALL AND EVENTUALLY DISSIPATE OVER THE SOUTHEAST
STATES...WHILE UPPER RIDGING BRIEFLY ATTEMPTS TO BUILD BACK INTO
THE REGION FROM THE SOUTH. WILL INDICATE MORE SEASONAL PRECIPITATION
COVERAGE FRIDAY AND SATURDAY...WITH ISOLATED TO SCATTERED
SHOWER/THUNDERSTORM ACTIVITY FOCUSED ALONG AND INLAND OF THE
SEABREEZE EACH AFTERNOON/EARLY EVENING. THERE IS RATHER
SIGNIFICANT DISAGREEMENT BETWEEN MEDIUM RANGE MODELS REGARDING THE
STRENGTH OF ANOTHER UPPER TROUGH RAPIDLY MOVING INTO THE REGION
SUNDAY AND MONDAY. PREFER TO MAINTAIN SOMEWHAT GENERIC RAIN
CHANCES PEAKING IN THE 30 PERCENT RANGE EARLY NEXT WEEK UNTIL
BETTER MODEL CONSISTENCY IS EVIDENT. HIGH TEMPERATURES WILL REACH
THE LOWER 90S AWAY FROM THE COASTLINE EACH AFTERNOON.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
TO BE ISSUED.
EXTENDED AVIATION OUTLOOK...LITTLE CHANGE IN THE PATTERN THROUGH
THURSDAY...WITH MAINLY DIURNAL CONVECTION AND THE CHANCE FOR LATE
NIGHT/EARLY MORNING STRATUS. THIS WILL RESULT IN PERIODIC FLIGHT
RESTRICTIONS THROUGH THE PERIOD.
&&
.MARINE...
TODAY AND TONIGHT...SOMEWHAT ELEVATED WINDS WILL REMAIN IN PLACE
TODAY WITH SPEEDS GENERALLY 15-20 KT...EXCEPT CLOSER TO 15 KT IN
THE CHARLESTON HARBOR. SEAS WILL RANGE FROM 2-4 FT NEARSHORE
WATERS AND 4-5 FT OFFSHORE WATERS. ATTM IT APPEARS BOTH WINDS AND
SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. SIMILAR
CONDITIONS ARE EXPECTED TONIGHT.
TUESDAY AND WEDNESDAY...THE COASTAL WATERS WILL REMAIN BETWEEN
THE SUB-TROPICAL ATLANTIC RIDGE TO THE SOUTH/SOUTHEAST...WHILE A
PERSISTENT TROUGH OF LOW PRESSURE LINGERS INLAND. THE PRESSURE
GRADIENT WILL BE UNSEASONABLY ENHANCED AS A RESULT...SUPPORTING
WIND SPEEDS ABOVE NORMAL FOR LATE JULY. EXPECT WINDS TO PEAK AT 15
TO 20 KT THROUGH THE PERIOD...WITH OCCASIONAL GUSTS UP TO 25 KT.
SMALL CRAFT ADVISORIES DO NOT APPEAR NECESSARY AT THIS TIME DUE TO
THE INFREQUENCY OF HIGHER GUSTS. DIRECTIONS WILL BE MAINLY
SOUTHWEST...VEERING A LITTLE AT NIGHT AND BACKING SOME DURING THE
DAY WITHIN SEABREEZE CIRCULATIONS. SEAS WILL BE HELD UNDER 5 FT.
MARINERS ARE ADVISED THAT ISOLATED SHOWERS AND THUNDERSTORMS
COULD BECOME STRONG...WITH FREQUENT LIGHTNING AND HEAVY RAIN.
ISOLATED STORMS COULD ALSO PRODUCE WIND GUSTS IN EXCESS OF 35
KT...AND SPECIAL MARINE WARNINGS MAY BECOME NECESSARY. CHECK
NATIONAL WEATHER SERVICE FORECASTS AND NOAA WEATHER RADIO ALL
HAZARDS BEFORE AND DURING ANY NAVIGATION INTO THE COASTAL WATERS.
THURSDAY AND FRIDAY...THE PRESSURE GRADIENT WILL WEAKEN
CONSIDERABLY LATE IN THE WEEK...AS THE INLAND TROUGH DRIFTS TOWARD
THE COAST AND THE COLD FRONT STALLS INLAND. LIGHT WINDS COULD
ACTUALLY BECOME VARIABLE AT TIMES...GENERALLY CAPPED NO HIGHER
THAN 10 KT. OUTSIDE OF ANY CONVECTION...WINDS AND SEAS WILL BE
WELL BELOW ANY SMALL CRAFT CONDITIONS.
&&
.TIDES/COASTAL FLOODING...
THE PERIGEAN SPRING TIDES WILL PERSIST TODAY SO ONLY SMALL
POSITIVE TIDAL DEPARTURES MAY PRODUCE MINOR COASTAL FLOODING.
SHOULD ANY SHALLOW SALT WATER COASTAL FLOODING OCCUR THE MOST
LIKELY AREAS ARE CHARLESTON AND COASTAL COLLETON COUNTIES DURING
THE EVENING HIGH TIDES THROUGH WEDNESDAY. IT IS IN THESE AREAS
WHERE THE SMALLEST TIDAL DEPARTURES ARE REQUIRED FOR THE ISSUANCE
OF AN ADVISORY. WE HAVE MAINTAINED MENTION OF THIS POTENTIAL IN
THE HAZARDOUS WEATHER OUTLOOK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/WMS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1025 AM EDT MON JUL 22 2013
.UPDATE...
ISSUED AT 1025 AM EDT MON JUL 22 2013
13Z SFC ANALYSIS SHOWS A DEVELOPING AREA OF LOW PRESSURE MOVING INTO
THE OHIO VALLEY. THIS DEVELOPMENT IS OCCURRING DUE TO AN INBOUND AND
SHARPENING 500 MB SHORT WAVE THAT WILL CROSS NORTHERN KENTUCKY
LATER TODAY. AS SUCH...IT IS ALSO BRINGING WITH IT A LARGE CLUSTER OF
MAINLY MODERATE SHOWERS ALONG WITH A COUPLE OF EMBEDDED
THUNDERSTORMS. THE RAIN AREA IS POISED TO ENTER OUR CWA AND
PROGRESS FROM WEST TO EAST THROUGH THE REST OF THE MORNING. THE
LATEST HRRR DOES SHOW THIS AREA BREAKING UP TOWARD NOON AND MORE
SCATTERED CONVECTION DEVELOPING THROUGHOUT EAST KENTUCKY...
THEREAFTER. EXPECT THIS SECONDARY CONVECTION...TAPPING INTO HIGH PW
AIR IN PLACE...TO HAVE THE BEST CHANCE OF PRODUCING EXCESSIVE
RAINS...TRAINING...AND THE POTENTIAL FOR LOCALIZED FLASH FLOODING.
HAVE UPDATED THE GRIDS TO REFLECT THIS TYPE OF EVOLUTION TO THE
POPS...WX...AND QPF. ALSO...BUMPED UP TEMPS IN THE EAST A NOTCH DUE
TO A DECENT SUNNY PATCH MOVING THROUGH ATTM AHEAD OF THE INBOUND MASS
OF SHOWERS. MEANWHILE...TOOK DOWN THE MAX TEMPS IN THE WEST A TAD FOR
THE OPPOSITE REASON. OTHERWISE...THE THREAT FOR DOWNPOURS LOOKS GOOD
FOR MOST OF THE REGION SO WILL CONTINUE THE FFA AND MENTION OF
LOCALLY HEAVY RAIN IN THE ZONES/HWO THROUGH THE EVENING. FOR
TONIGHT...WILL HAVE TO LOOK CLOSELY AT THE POTENTIAL FOR DENSE FOG
IF WE MANAGE TO GET MUCH CLEARING AFTER THE RAINS OF TODAY. UPDATES
HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 753 AM EDT MON JUL 22 2013
UPSTREAM RADARS SHOW A LARGE CLUSTER OF SHOWERS AND STORMS MAKING A
BEELINE TOWARD EAST KENTUCKY. AS A RESULT...WE NUDGED POPS UP INTO
THE CATEGORICAL RANGE FOR ALL BUT OUR EASTERNMOST COUNTIES AS RECENT
HRRR RUNS SHOW THE SHOWERS BREAKING UP SOME AS THEY HEAD EAST OF JKL.
UPDATE ISSUED AT 655 AM EDT MON JUL 22 2013
MODIFIED THE FORECAST GRIDS TO REFLECT SLOWER ONSET OF PRECIPITATION
EARLY THIS MORNING. ALSO ISSUED AN UPDATE TO THE FLASH FLOOD WATCH.
THE NEW ZONES WILL BE ISSUED SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 310 AM EDT MON JUL 22 2013
MODELS IN PRETTY GOOD AGREEMENT ON THE OVERALL WEATHER PATTERN FOR
THE NEXT COUPLE OF DAY. CONSENSUS VIEW IS FOR WIDESPREAD SHOWERS AND
STORMS TO DEVELOP EARLY THIS MORNING AND PERSIST THROUGH THE END OF
THE DAY ON TUESDAY. THE PRIMARY CONCERN WILL BE LOCALLY HEAVY
RAINFALL AND FLOODING. WITH A DEEP LAYER OF MOISTURE IN THE
ATMOSPHERE AND WEAK MIDDLE AND UPPER LEVEL WINDS...ANY STORMS THAT
FORM WILL BE SLOW MOVING AND WILL HAVE THE POTENTIAL PRODUCE HEAVY
RAINFALL OVER VERY LOCALIZED AREAS...WHICH COULD LEAD TO FLASH
FLOODING. HIGH TEMPERATURES TODAY AND TOMORROW WILL BE SLIGHTLY BELOW
NORMAL...DUE TO THE INFLUENCE OF WIDESPREAD CLOUD COVER AND SHOWER
AND STORM ACTIVITY. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL OF
EASTERN KENTUCKY THROUGH MONDAY EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON JUL 22 2013
LONGWAVE TROUGH NOW BECOMING ESTABLISHED OVER THE EASTERN U.S. WILL
REMAIN IN PLACE THROUGH THE LONG TERM PERIOD. AT THE SURFACE...A
COLD FRONT WILL SLIP TO OUR SOUTH TUESDAY NIGHT AND WEDNESDAY WITH
HIGH PRESSURE BUILDING IN BEHIND. WHILE THE DEEPER MOISTURE WILL BE
TO OUR SOUTH BY TUESDAY NIGHT...THE FRONT WILL LIKELY KICK OFF
ISOLATED TO SCATTERED SHOWERS/STORMS AS IT PASSES. THE HIGH PRESSURE
SYSTEM WILL THEN USHER IN A MUCH DRIER AIR MASS FOR THURSDAY AND
FRIDAY. IN FACT...IT APPEARS DEWPOINTS MAY EVEN TUMBLE AS LOW AS THE
UPPER 50S BY THURSDAY AFTERNOON...WHICH WILL FEEL VERY NICE AFTER
THE RECENT PROLONGED BOUT OF 70 DEGREE DEWPOINTS.
FORECASTER CONFIDENCE THEN FALLS AS WE HEAD INTO THE WEEKEND. THE
UPPER LEVEL TROUGH WILL DIG BACK IN AFTER A BRIEF RELAXATION FORCING
A SURFACE FRONT SOUTHWARD INTO THE OHIO VALLEY. THE 22/00Z ECMWF
WANTS TO HOLD A PIECE OF THE UPPER TROUGH BACK OVER THE PLAINS...
WHILE THE 22/00Z GFS/GEM/UKMET DO NOT. THIS RESULTS IN A WETTER
SOLUTION IN THE GFS/GEM/UKMET MODELS WHILE THE ECMWF IS SLOWER TO
BRING IN ANY PRECIP. AS SUCH...WILL TREND BACK A LITTLE WITH POPS TO
REFLECT THE ADDED UNCERTAINTY BUT STILL OFFER SCATTERED SHOWERS AND
STORMS THROUGHOUT THE WEEKEND.
DAYTIME HIGHS WILL CHANGE LITTLE THROUGH THE PERIOD...REACHING THE
LOW TO MID 80S EACH DAY. OVERNIGHT LOWS WILL RESPOND TO THE FALLING
DEWPOINTS LATE IN THE WEEK...FALLING FROM THE MID TO UPPER 60S
TUESDAY NIGHT BACK INTO THE UPPER 50S TO LOW 60S THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 753 AM EDT MON JUL 22 2013
PRECIPITATION ONSET THIS MORNING WILL OCCUR BETWEEN 1430Z AND 16Z AT
THE TAF SITES AS A LARGE CLUSTER OF SHOWERS AND STORMS PROGRESSES
EASTWARD ACROSS THE REGION. EXPECTING MVFR CONDITIONS TO PREVAIL AT
THE TAF SITES ONCE THE RAIN BEGINS TO FALL. THE CLUSTER OF SHOWERS
WILL SHIFT EAST DURING THE AFTERNOON WITH A LESS WELL DEFINED THREAT
FOR SHOWERS AND STORMS FROM LATE AFTERNOON INTO THE EVENING HOURS.
LOW CLOUDS AND FOG WILL THEN BECOME A HAZARD TO AVIATION LATE
TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...ABE
AVIATION...AR/ABE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
643 AM EDT MON JUL 22 2013
...Updated Aviation Discussion...
.FORECAST UPDATE...
Issued at 640 AM EDT Mon Jul 22 2013
A solid line of showers has formed along a Theta-E ridge running
from NW TN to FTK. A broad meso has formed along that line and is
getting ready to move into our southwest forecast area. KHPX radar
indicates a nice low-level jet, with winds of 35-40 knots at ~2500
feet. Tried blending ongoing radar trends with RAP forecasts for
this Theta-E ridge over the next couple of hours to get a PoP
forecast. Updated products are out.
&&
.SHORT TERM (Today through Tuesday)...
Issued at 315 AM EDT Sun Jul 21 2013
Pronounced shortwave trough, centered now along the northern MO/IL
border will move into our region today. Combined with a tropical
airmass in place, and we should see another round of showers and
storms this morning into the afternoon. Seeing one line of storms
forming over the MO/AR border into western KY and another one closer
to a stationary front to our north, along the central IL/IN border.
With additional storms in the forecast, have decided to lift a flash
flood watch for a portion of our forecast area. The Bluegrass has
the lowest flash flood guidance, with 3-hour guidance between 1.5
and 2 inches. Areal average QPF for that region is around an inch,
but it easily could be higher with any slow-moving heavy storms.
Airmass looks too tropical for severe weather, though we do look to
have a weak low moving up the Ohio Valley ahead of the upper level
feature, so will have to watch for some rotation in any storms that
form.
We should see a break in the precip tonight, but the airmass does
not dry out until after this period, so cannot rule out additional
isolated storms. Another wave looks to come across the area Tuesday,
bringing enhanced rain chances once more. Coverage should be more
limited than today, but soundings favor a better chance for stronger
storms, with gusty winds and hail as the main threats.
Temperatures today will depend on how quick the precip exits our
region this afternoon. Have gone with higher values over the west,
mid 80s compared with around 80 for the east. Temperatures tonight
should be similar to this morning, with no real change in airmass.
Readings should warm back into the upper 80s for Tuesday.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 300 AM EDT Mon Jul 22 2013
Longwave 500mb upper air pattern early Wednesday will feature a
broad ridge centered over the Intermountain West and a robust trough
centered over the Great Lakes. Northwest flow will influence the
Lower Ohio Valley. Ultimately, this pattern will bring pleasant,
seasonably cool weather and relatively low dewpoints, especially for
the period Wednesday through Friday.
Several weak waves may move southeast across the Lower Ohio Valley
Tuesday through Saturday. The first will cross the Ohio River
Tuesday evening. High pressure over the upper midwest will build in
behind a cold front that will move across the Commonwealth during
the early morning hours Wednesday. Scattered convection will likely
end from the north to the south during the morning hours Wednesday
as drier air arrives from the northwest.
Think that Wednesday afternoon will stay dry with noticeably less
humid conditions. Northwesterly winds behind this front will lower
dewpoints into the upper 50s by Wednesday evening.
High pressure will build across the northern Ohio Valley Thursday
and continue through Friday. Expect mostly clear skies with
comfortable nights. Highs will stay in the mid 80s with lows well
down into the 60s. The proximity of the surface high to our north
will lead to light northeasterly to easterly winds through early
Saturday.
For several days now, long range guidance has advertised a quick
return of moisture ahead of an upper wave on Saturday. Showers and
storms may approach as early as Saturday morning and continue during
the day Saturday just ahead of a progressive 500mb trough.
Temperatures still will stay relatively mild Saturday and Sunday,
with highs in the 80s and upper 60s at night. Expect clearing Sunday
with dry conditions.
&&
.AVIATION (12Z TAF Update)...
Issued at 645 AM EDT Mon Jul 22 2013
Very moist atmosphere remains in place ahead of an upper level
disturbance forecast to move through the region this afternoon. Have
tried to time storms based on RAP forecasts for now, with periods of
at least MVFR conditions. Rain chances should become more limited
when that trough comes through so have kept in some VFR cigs by
mid/late afternoon with no storms. We may see some light fog by the
end of the period, given no real change in airmass and muggy
conditions, but will leave out of the forecast for now to keep the
number of lines in the TAFs down.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ036-037-041>043-
048-049-057.
$$
Update...........RJS
Short Term.......RJS
Long Term........JSD
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1200 PM EDT MON JUL 22 2013
.SYNOPSIS...
ISSUED AT 407 AM EDT MON JUL 22 2013
HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH
ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE
NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS
THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS
NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS
AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF
OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO
NORTHERN MICHIGAN.
&&
.UPDATE...
ISSUED AT 1200 PM EDT MON JUL 22 2013
MID MORNING SURFACE ANALYSIS SHOWS 999MB LOW CENTER OVER NORTHWEST
ONTARIO JUST NORTH OF THE BOUNDARY WATERS...TRAILING COLD FRONT
EXTENDS BACK INTO SOUTHWEST MINNESOTA/EASTERN NEBRASKA WITH A WARM
FRONT EXTENDING SOUTHEAST ACROSS CENTRAL UPPER/NORTHWEST LOWER
MICHIGAN. MOISTURE HAS BEEN INCREASING ACROSS MICHIGAN OVER THE
LAST 24 HOURS...PRECIPITABLE WATER ON 12Z APX SOUNDING HAS DOUBLED
SINCE 12Z SUNDAY (1.07 INCHES). STRAIGHT MODIFICATION OF THE
SOUNDING MIXING TO 800MB (78/58) ONLY YIELDS AROUND 400J/KG MLCAPE
BUT DEW POINTS HAVE BEEN CLIMBING INTO THE LOWER 60S...AND
TEMPERATURES ALREADY IN THE MID/UPPER 70S. SO AN 81/63 PARCEL
PUSHES MLCAPE VALUES ABOVE 1100J/KG. ALREADY GETTING SOME CU
DEVELOPING EAST OF AN LDM-PZQ LINE...AND A FEW RADAR RETURNS
POPPING UP ALONG THE THUMB.
BASIC FORECAST IDEAS WILL REMAIN INTACT WITH CONVECTION POPPING UP
THIS AFTERNOON...WITH 1000-1500J/KG MLCAPE EXPECTED. WILL KEEP
NORTHWEST LOWER SHORELINE COUNTIES DRY WITH AN ONSHORE BREEZE/LAKE
SHADOW. DEEP LAYER SHEAR NOT STRONG TODAY...SOME DECENT VEERING OF
WINDS ALOFT BUT NOT MUCH SPEED SHEAR (0-6KM BULK SHEAR VALUES
20-30KTS). HAVE BEEN ADJUSTING THE TIMING A BIT GIVEN CURRENT
TRENDS. FORECAST HIGHS UPPER 70S-MID 80S LOOK FINE.
UPDATE ISSUED AT 638 AM EDT MON JUL 22 2013
ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN
SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN
ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY
STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF
HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM
FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE
ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON
FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD
POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE
INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD
STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE
EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT
SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END
CHANCE FOR A SEVERE STORM OR TWO.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 407 AM EDT MON JUL 22 2013
INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN
CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE
A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT.
OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING
ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME
ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN
MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER
FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN
BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF
07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS
THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX
LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH
THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST
NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A
SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND
WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE
LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR
NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW
OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN
RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY
ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE
OF LAKE MICHIGAN.
CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A
FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER
LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH
LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH
INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH
BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF
THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME
POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY
MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS
WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF
CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A
SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER
LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION
THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT
NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES
NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN.
THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY
AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS
RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY
IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL
PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM
ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE
LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW
SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z.
INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE
UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST
CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS
CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL
LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T
LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER
PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT
BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY
WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY
AREAS.
THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE
THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN
ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z.
BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A
LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD
1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE
SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST
AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING
EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL
TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY
CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE
OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND
MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY
SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF
THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S
THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE
BOUNDARY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON JUL 22 2013
THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC
TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT
WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY
EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK
WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING
STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER
RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF
THE NEXT WORK WEEK.
TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT
UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY
MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN
THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD.
TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY
COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN
THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH
THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL
SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL
WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN
OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO
ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES
INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW
WISCONSIN.
THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE
AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE.
TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS
AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT.
REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL
RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS
THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT
IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW
OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME
TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET
EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED
ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A
RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL
ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED
LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING
RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES
FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE
APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES
IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND
LOWER 70S FOR THE UPCOMING WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM EDT MON JUL 22 2013
A WARM FRONT IS LIFTING THROUGH NRN MICHIGAN EARLY THIS
MORNING...AND THE EARLIER ASSOCIATED LIGHT RAIN SHOWERS/SPRINKLES
HAVE EXITED NE LOWER. COULD STILL SEE A FEW LIGHT SHOWERS POP OFF
THROUGH MID MORNING...BUT A WEDGE OF DRIER AIR HAS FILLED IN OVER
THE REGION. LOW LEVEL MOISTURE WILL ADVECT NORTHWARD AND INTO NRN
MICHIGAN THROUGH THE DAY...AND THE SUNSHINE SEEN THIS MORNING WILL
HELP DESTABILIZE THE ATMOSPHERE ENOUGH TO WHERE SCATTERED SHOWERS
AND A FEW STORMS ARE EXPECTED TO POP OFF AS EARLY AS 15Z...BUT
MORE SO THIS AFTERNOON. THE BEST CHANCE FOR POSSIBLE BRIEF MVFR
CIGS/VSBYS WILL BE AT APN...WITH THE EXPECTED DEVELOPMENT JUST
EAST OF PLN/TVC/MBL.
THIS CONVECTION WILL DIE OFF INTO THE EVENING...BUT UPSTREAM THERE
IS ANOTHER SHORTWAVE TROUGH ALOFT AND ASSOCIATED COLD FRONT THAT
WILL BE PUSHING THROUGH OVERNIGHT. THESE FEATURES WILL HAVE A
BETTER CHANCE FOR BRINGING SHOWERS AND STORMS TO ALL TAF SITES.
THERE IS A CHANCE THAT A STORM OVERNIGHT WILL BE ABLE TO BECOME
SEVERE WITH THE OUTSIDE POTENTIAL FOR DAMAGING WINDS AND LARGE
HAIL. CHANCES WAY TOO SMALL FOR ANY ONE LOCATION TO ACTUALLY SEE
THIS SEVERITY...MUCH LESS GET RAINED ON. AT MOST...WILL INTRO A
VCTS/CB GROUP.
DEVELOPING GUSTY SW WINDS THIS AFTERNOON WILL SHIFT OUT OF THE NW
LATE IN THE TAF PERIOD BEHIND THE COLD FRONT.
&&
.MARINE...
ISSUED AT 407 AM EDT MON JUL 22 2013
LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST
AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING
THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT
ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND
TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS.
THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH
THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS
THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF
SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD
PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE
WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING
HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED.
HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK...
GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH
THURSDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JPB
SYNOPSIS...SD
SHORT TERM...DL
LONG TERM...SD
AVIATION...SD
MARINE...DL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1110 AM EDT MON JUL 22 2013
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 330 AM EDT MON JUL 22 2013
A WARM FRONT WILL BRING A FEW SHOWERS AND THUNDERSTORMS LATER TODAY
AND THEN A COLD FRONT WILL BRING MORE SCATTERED SHOWERS AND STORMS
TONIGHT INTO TUESDAY. FAIR AND COOLER WEATHER WILL ARRIVE BY LATE
TUESDAY AND LAST THROUGH THURSDAY. TEMPERATURES WILL AVERAGE NEAR
NORMAL LATE IN THE WEEK THROUGH NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 1110 AM EDT MON JUL 22 2013
DROPPED MAXIMUM TEMPERATURES TODAY SLIGHTLY MAINLY SOUTH OF I-96
TO ACCOUNT FOR THE COOLING EFFECTS OF EXTENSIVE PRECIPITATION
OVERNIGHT AND RESIDUAL CLOUD COVER. ALSO RAISED PRECIPITATION
CHANCES EAST OF US-131 BASED ON HRRR MODEL GUIDANCE AND TO BETTER
AGREE WITH SURROUNDING OFFICES. MAIN FORECAST CONCERN THIS
AFTERNOON WILL BE PRECIPITATION CHANCES OVERNIGHT WITH THE
APPROACHING COLD FRONT.
UPDATE ISSUED AT 537 AM EDT MON JUL 22 2013
A COUPLE OF SHOWERS DEVELOPED IN THE PAST HR...ESPECIALLY NEAR
LWA. WENT AND ADDED A RISK FOR A FEW EARLY MORNING SHOWERS
PRIMARILY SOUTH OF A BIV TO LAN LINE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON)
ISSUED AT 330 AM EDT MON JUL 22 2013
AFTER SOME LINGERING EARLY MORNING SHOWERS OVER OUR SE FCST AREA DRY
WX IS ANTICIPATED FOR THE REST OF THE MORNING IN THE WAKE OF THE
DEPARTING MCV THAT BROUGHT THE ROUND OF RAIN AND STORMS YESTERDAY
EVENING AND OVERNIGHT.
SOME WAA SHOWERS AND A FEW STORMS WILL DEVELOP THIS AFTERNOON. A
FAIR AMOUNT OF SUN AND SSW WINDS WILL HELP
TO BOOST MAX TEMPS INTO THE LOWER TO MIDDLE 80S ACROSS MOST OF OUR
AREA TODAY.
THE COLD FRONT WILL MOVE IN FROM THE NW TONIGHT AND BRING SCATTERED
SHOWERS AND STORMS WHICH WILL LAST THROUGH ABOUT MIDDAY TUESDAY
BEFORE THE FRONT CLEARS OUR AREA. A COOLER AND DRIER AIRMASS WILL
ADVECT IN BEHIND THAT FRONT AND MAX TEMPS WEDNESDAY WILL ONLY REACH
THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON JUL 22 2013
PATTERN IS LOOKING COOLER WITH TIME ESPECIALLY THIS WEEKEND. MODELS
IN DECENT AGREEMENT IN SHOWING A COLD FRONT PUSHING THROUGH FRI
NIGHT INTO SAT WITH A WAVE OF LOW PRESSURE FORMING ON IT OVER
SOUTHERN LOWER MI. THIS SHOULD LEAD TO SHOWERS AND WITH INSTABILITY
AROUND THUNDERSTORMS. IF THE NEW HIGH RES EURO IS CORRECT SAT COULD
BE A RATHER WET DAY FOR THE AREA. NORTHERLY FLOW SETS UP BEHIND
THE WAVE LEADING TO STRONG COLD AIR ADVECTION. 925 MB TEMPS FALL
TO UNDER 10 DEG C 12Z SUN. IF THIS HAPPENS AND THE UPPER LOW
DEVELOPS NORTH OF SUPERIOR AS SHOWN BY THE HIGH RES EURO ON
SUN...LAKE ENHANCED MOISTURE MAY IMPACT THE FORECAST. I LOWERED
TEMPERATURES OVER GUIDANCE FOR SAT NIGHT THROUGH SUN BASED ON THIS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 537 AM EDT MON JUL 22 2013
LIGHT RAIN SOUTH OF KAZO TRYING TO WORK NORTH AT THIS TIME.
PRECIPITATION IS FALLING OUT OF MID LEVEL CLOUDS...SO VFR WEATHER
EXPECTED EVEN IF THE RAIN DOES MOVE IN. THE LOW LEVELS ARE MOIST
SO AN INCREASED RISK FOR MVFR/IFR EXISTS...BUT CONFIDENCE THAT IT
WILL OCCUR IS TOO LOW TO ADD IT TO THE FORECAST. THE NEXT BATCH OF
RAIN WITH POSSIBLE THUNDERSTORMS ARRIVES IN KMKG FIRST AROUND
04Z...THEN THE RAIN TRACKS SOUTHEAST FOR THE REMAINDER OF THE
NIGHT. WE MAY SEE MVFR CONDITIONS WITH THIS RAIN LATER TONIGHT.
THE IFR OR LOWER CONDITIONS CURRENTLY IN WI...ARE EXPECTED TO NOT
REACH THE TAF SITES TODAY.
&&
.MARINE...
ISSUED AT 1110 AM EDT MON JUL 22 2013
LATEST OMR SHOWS WAVEHEIGHTS GENERALLY BELOW 2 FEET...ALTHOUGH 3
FEET WAS REPORTED AT GRAND HAVEN. AS NOTED IN THE PREVIOUS
DISCUSSION...WINDS AND WAVES WILL INCREASE TODAY. ALTHOUGH A SMALL
CRAFT ADVISORY IS NOT ANTICIPATED...WE WILL HAVE TO WATCH THE
BEACH HAZARD POTENTIAL /PRIMARILY INCREASING LONGSHORE CURRENTS/
AS IT EVOLVES THIS AFTERNOON AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT MON JUL 22 2013
NO HYDRO ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...TJT
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MJS
AVIATION...MJS
HYDROLOGY...LAURENS
MARINE...TJT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
703 AM EDT MON JUL 22 2013
.SYNOPSIS...
ISSUED AT 407 AM EDT MON JUL 22 2013
HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH
ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE
NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS
THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS
NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS
AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF
OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO
NORTHERN MICHIGAN.
&&
.UPDATE...
ISSUED AT 638 AM EDT MON JUL 22 2013
ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN
SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN
ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY
STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF
HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM
FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE
ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON
FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD
POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE
INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD
STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE
EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT
SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END
CHANCE FOR A SEVERE STORM OR TWO.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 407 AM EDT MON JUL 22 2013
INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN
CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE
A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT.
OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING
ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME
ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN
MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER
FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN
BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF
07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS
THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX
LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH
THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST
NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A
SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND
WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE
LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR
NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW
OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN
RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY
ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE
OF LAKE MICHIGAN.
CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A
FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER
LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH
LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH
INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH
BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF
THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME
POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY
MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS
WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF
CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A
SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER
LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION
THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT
NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES
NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN.
THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY
AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS
RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY
IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL
PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM
ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE
LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW
SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z.
INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE
UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST
CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS
CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL
LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T
LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER
PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT
BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY
WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY
AREAS.
THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE
THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN
ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z.
BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A
LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD
1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE
SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST
AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING
EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL
TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY
CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE
OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND
MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY
SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF
THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S
THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE
BOUNDARY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON JUL 22 2013
THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC
TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT
WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY
EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK
WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING
STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER
RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF
THE NEXT WORK WEEK.
TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT
UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY
MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN
THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD.
TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY
COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN
THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH
THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL
SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL
WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN
OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO
ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES
INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW
WISCONSIN.
THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE
AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE.
TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS
AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT.
REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL
RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS
THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT
IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW
OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME
TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET
EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED
ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A
RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL
ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED
LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING
RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES
FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE
APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES
IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND
LOWER 70S FOR THE UPCOMING WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM EDT MON JUL 22 2013
A WARM FRONT IS LIFTING THROUGH NRN MICHIGAN EARLY THIS
MORNING...AND THE EARLIER ASSOCIATED LIGHT RAIN SHOWERS/SPRINKLES
HAVE EXITED NE LOWER. COULD STILL SEE A FEW LIGHT SHOWERS POP OFF
THROUGH MID MORNING...BUT A WEDGE OF DRIER AIR HAS FILLED IN OVER
THE REGION. LOW LEVEL MOISTURE WILL ADVECT NORTHWARD AND INTO NRN
MICHIGAN THROUGH THE DAY...AND THE SUNSHINE SEEN THIS MORNING WILL
HELP DESTABILIZE THE ATMOSPHERE ENOUGH TO WHERE SCATTERED SHOWERS
AND A FEW STORMS ARE EXPECTED TO POP OFF AS EARLY AS 15Z...BUT
MORE SO THIS AFTERNOON. THE BEST CHANCE FOR POSSIBLE BRIEF MVFR
CIGS/VSBYS WILL BE AT APN...WITH THE EXPECTED DEVELOPMENT JUST
EAST OF PLN/TVC/MBL.
THIS CONVECTION WILL DIE OFF INTO THE EVENING...BUT UPSTREAM THERE
IS ANOTHER SHORTWAVE TROUGH ALOFT AND ASSOCIATED COLD FRONT THAT
WILL BE PUSHING THROUGH OVERNIGHT. THESE FEATURES WILL HAVE A
BETTER CHANCE FOR BRINGING SHOWERS AND STORMS TO ALL TAF SITES.
THERE IS A CHANCE THAT A STORM OVERNIGHT WILL BE ABLE TO BECOME
SEVERE WITH THE OUTSIDE POTENTIAL FOR DAMAGING WINDS AND LARGE
HAIL. CHANCES WAY TOO SMALL FOR ANY ONE LOCATION TO ACTUALLY SEE
THIS SEVERITY...MUCH LESS GET RAINED ON. AT MOST...WILL INTRO A
VCTS/CB GROUP.
DEVELOPING GUSTY SW WINDS THIS AFTERNOON WILL SHIFT OUT OF THE NW
LATE IN THE TAF PERIOD BEHIND THE COLD FRONT.
&&
.MARINE...
ISSUED AT 407 AM EDT MON JUL 22 2013
LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST
AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING
THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT
ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND
TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS.
THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH
THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS
THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF
SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD
PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE
WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING
HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED.
HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK...
GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH
THURSDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...SD
SHORT TERM...DL
LONG TERM...SD
AVIATION...SD
MARINE...DL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
640 AM CDT MON JUL 22 2013
.UPDATE...
FOR 12Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT MON JUL 22 2013
EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE
TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE
SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING
FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN
OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE
ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE
TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT
COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS
SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE
ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT
BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE
22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING
SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE
SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL
WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING
THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE
INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR
STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH
CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG
THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY
/MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK
SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW
FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35.
CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE
FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT.
HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST
CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE
AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH
GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS
TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND
LOWER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 AM CDT MON JUL 22 2013
MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY
PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS
IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF
CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A
BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT.
THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A
SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN
STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS
THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT
CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL
BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES
RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST
MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS
WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH
SATURDAY.
AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF
TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO
THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND
MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE
GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE
ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO
FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS
KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE
SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE
DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF
THE BUNCH.
FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN
IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ
FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN
A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK
TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES
IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED
OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS
MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR
ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE
POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY
POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE
BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF
MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA
OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE.
ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF
WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND
ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE
MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH.
IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS
WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE
22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD
LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK
TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED
LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE
ABLE MAKE A RUN AT THAT RECORD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 617 AM CDT MON JUL 22 2013
THERE SHOULD BE AN OVERALL LULL IN CONVECTIVE ACTIVITY FOR THE
NEXT SEVERAL HOURS...WITH REDEVELOPMENT EXPECTED BY 16Z AS DIURNAL
DESTABILIZATION OCCURS IN CONJUNCTION WITH THE ADVANCING COLD
FRONT. SHOWERS AND THUNDERSTORMS SHOULD MOSTLY BE CONFINED TO FAR
EAST CENTRAL MN AND WEST CENTRAL WI...WITH KMSP BEING ON THE
WESTERN EDGE OF THE REDEVELOPMENT AREA. HAVE INCLUDED VCTS AT
KMSP...TEMPOS AT WI SITES /KRNH AND KEAU/...AND DRY ELSEWHERE FOR
THIS AFTERNOON. LOW-END VFR TO HIGH-END MVFR CONDITIONS POSSIBLE
WITH ANY CONVECTION. SOUTH/SOUTHWEST WINDS AHEAD OF THE
FRONT...VEERING TO NORTHWEST AND GUSTING TO BETWEEN 20 AND 25
/KNOTS/ WITH THE FROPA. CLEARING SKIES THIS EVENING...WITH VFR
CONDITIONS THROUGH THE REMAINDER OF THE PERIOD.
KMSP...
COULD SEE A PERIOD OF SCT MVFR CIGS AS STRATUS OVER SERN MN
CREEPS NORTH THIS MORNING...BUT EXPECT THAT TO BREAK UP AS DRIER
AIR IS ENCOUNTERED. OTHERWISE...THERE/S A LOW CHANCE FOR
THUNDERSTORM REDEVELOPMENT DURING THE LATE MORNING AND EARLY
AFTERNOON AS THE COLD FRONT PASSES. HOWEVER...COVERAGE IS EXPECTED
TO BE SPOTTY WITH HIGHER CHANCES TO THE EAST OF KMSP...SO HAVE
ONLY INCLUDED A VCTS AT THIS POINT. SOUTH/SOUTHWEST WINDS THROUGH
THE MORNING AHEAD OF THE FRONT...THEN SHIFTING TO THE NORTHWEST
AND GUSTING TO AROUND OR JUST OVER 20 KTS THIS AFTERNOON BEHIND
THE FRONT.
/OUTLOOK FOR KMSP/
TUE...VFR. WINDS N 5 TO 10 KT.
WED...VFR. MVFR WITH A CHANCE OF SHRA/TSRA LATE NIGHT. WINDS S 5 KT.
THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS WSW 5 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...MPG
AVIATION...LS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
911 AM CDT MON JUL 22 2013
.UPDATE...
ISSUED AT 911 AM CDT MON JUL 22 2013
FIRST FORECAST UPDATE OF THE DAY HAS BEEN SENT. IN SHORT...ANOTHER
TRICKY DAY/EVENING OF THUNDERSTORM CHANCES AWAITS THE LOCAL AREA.
ESSENTIALLY...THE ONLY NOTABLE CHANGE FROM PREVIOUS FORECAST SO
FAR WAS TO TRIM CENTRAL/NORTHEAST PORTIONS OF THE CWA FROM ANY
THUNDERSTORM MENTION THIS MORNING...WHILE LEAVING MORNING CHANCES
INTACT IN KS ZONES...AND MAINLY WEST OF A GOTHENBURG-ALMA LINE IN
NEBRASKA TO ACCOUNT FOR THE FAIRLY PERSISTENT NARROW NORTHWEST-
SOUTHEAST AXIS OF CONVECTION PRIMARILY AFFECTING FURNAS COUNTY AT
THIS TIME. OTHER THAN MAYBE SOME SMALL HAIL...NOT EXPECTING A
MORNING SEVERE THREAT. FOR THIS AFTERNOON...ITS HARD TO ARGUE WITH
THE SPC SLIGHT RISK FOR ROUGHLY THE SOUTHEAST 2/3 OF THE
CWA...ALTHOUGH ITS TOUGH TO SAY WHETHER WE MIGHT ONLY GET 1 OR 2
ISOLATED STRONG-SEVERE STORMS...OR POTENTIALLY MORE SCATTERED
COVERAGE. EITHER WAY...THE PRIMARY FORCING MECHANISM ALOFT LOOKS
TO BE A FAIRLY SUBTLE SHORTWAVE TROUGH DRIFTING EAST-SOUTHEAST OUT
OF WYOMING...WHILE AT THE SURFACE A FAIRLY WEAK COLD FRONT WILL
SINK SOUTHWARD INTO PARTS OF THE CWA AS THE DAY WEARS
ON...PROVIDING AT LEAST LIMITED LOW-LEVEL CONVERGENCE. THE LATEST
RAP FORECAST VALID FOR 21Z/4PM PAINTS 1000-2500 J/KG OF 0-1KM
MLCAPE ACROSS MOST OF THE CWA...HIGHEST IN THE SOUTH...IN THE
PRESENCE OF DECENT 0-6KM DEEP LAYER SHEAR OF 35-40KT...SO
CERTAINLY A THREAT FOR SOME SOUTHEAST-MOVING STRONG TO SEVERE
STORMS AND POTENTIALLY SUPERCELLS EXISTS...ALTHOUGH WORKING AGAINST
STORM FORMATION APPEARS TO BE AT LEAST A WEAK CAP EVIDENT ON
FORECAST SOUNDINGS AROUND 700-650 MILLIBARS...SO ITS ALSO NOT OUT
OF THE QUESTION THAT OUR LOCAL AREA COULD LARGELY STEER CLEAR OF
AN AFTERNOON/EVENING STORM THREAT...WITH BETTER CHANCES
POTENTIALLY FOCUSING JUST TO OUR SOUTH/EAST. EVEN THOUGH THE
GREATEST SEVERE THREAT WOULD THEORETICALLY FOCUS ACROSS SOUTHERN
PORTIONS OF OUR AREA...HAVE PUT AT LEAST A SLIGHT CHANCE OF STORMS
EVEN IN FAR NORTHERN COUNTIES FOR AT LEAST A FEW HOURS THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT MON JUL 22 2013
THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST
THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN
COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH
SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL
GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO
NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND
SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER
BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF
THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE
UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE
EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF
THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR
THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR
FLOW.
THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF
DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS
WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND
MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR
SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS
TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE
WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED
LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS
COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING
CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES
THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE
RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH
WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS
ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND
06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD
NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY
CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE
DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST
OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED
CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD
PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF
AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE
MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE
AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY
THEN.
THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS
AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST
AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR
VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY
WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE
TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE
LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST
STORMS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 349 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS WILL BE
CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND
TEMPERATURES.
MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE
PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN
DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A
LITTLE DIFFERENT WITH EACH MODEL.
THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY
NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS
SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS
DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE
EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE
AREA. TEMPERATURES WILL BE COOLER THAN TODAY.
A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND
INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY.
TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY
WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF
THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE
IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY
NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME
LINGERING THUNDERSTORMS.
FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL
WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY
MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE
OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER
SIDE DURING THIS TIME.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z TUESDAY MORNING)
ISSUED AT 523 AM CDT MON JUL 22 2013
WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS AT KGRI...BUT ANY
THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY
OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL
MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY
BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE
PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE EAST
NORTHEAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
625 AM CDT MON JUL 22 2013
.AVIATION... 12Z TAFS FOR KOFK...KLNK AND KOMA.
AS HAS BEEN THE CASE FOR THE PAST FEW DAYS...THE MAIN CONCERN AND
THE PRIMARY CHALLENGE FOR THE TAFS WILL BE THUNDERSTORM DEVELOPMENT.
TODAY A COLD FRONT WILL MOVE THROUGH EASTERN NEBRASKA...SWITCHING
THE WINDS FROM MOSTLY SOUTHERLY TO THE NORTHWEST. THE FRONT IS
EXPECTED TO REACH KOFK AT 16Z...KOMA AT 21Z...AND KLNK AT 22Z. THE
FRONT WILL HELP TO TRIGGER THUNDERSTORM DEVELOPMENT...BUT BETTER
CHANCES ARE AT KOMA AND KLNK BECAUSE THE INSTABILITY WILL BE GREATER
WHEN THE FRONT COMES THROUGH THOSE LOCATIONS. THEREFORE HAVE
INCLUDED TSRA PROB30 GROUPS FOR THOSE TWO TAFS. A FEW STRONG OR
EVEN SEVERE STORMS WILL BE POSSIBLE. GENERALLY EXPECT ANY
CONVECTION THAT DEVELOPS TODAY TO EVENTUALLY DIMINISH OVERNIGHT AND
EXPECT VFR CONDITIONS AFTER ANY THUNDERSTORMS.
NIETFELD
&&
.PREV DISCUSSION... /ISSUED 304 AM CDT MON JUL 22 2013/
.DISCUSSION...
PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE
CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z
WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA
INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL
NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA
BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA
THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY
STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN
THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND
OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY
EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE
WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO
THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH
SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35
KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND
THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING.
SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION
REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST
THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH
PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE
SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY
WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS
THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST
THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S
ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL
SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER
INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD
LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH
SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS
ARE EXPECTED TUESDAY AS WELL.
THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY
THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING
THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN
PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A
SMALL PRECIP CHANCE SUNDAY INTO MONDAY.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
532 AM CDT MON JUL 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT MON JUL 22 2013
THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST
THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN
COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH
SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL
GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO
NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND
SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER
BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF
THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE
UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE
EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF
THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR
THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR
FLOW.
THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF
DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS
WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND
MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR
SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS
TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE
WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED
LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS
COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING
CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES
THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE
RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH
WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS
ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND
06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD
NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY
CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE
DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST
OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED
CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD
PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF
AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE
MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE
AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY
THEN.
THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS
AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST
AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR
VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY
WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE
TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE
LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST
STORMS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 349 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS WILL BE
CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND
TEMPERATURES.
MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE
PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN
DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A
LITTLE DIFFERENT WITH EACH MODEL.
THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY
NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS
SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS
DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE
EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE
AREA. TEMPERATURES WILL BE COOLER THAN TODAY.
A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND
INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY.
TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY
WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF
THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE
IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY
NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME
LINGERING THUNDERSTORMS.
FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL
WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY
MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE
OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER
SIDE DURING THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 523 AM CDT MON JUL 22 2013
WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS AT KGRI...BUT ANY
THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY
OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL
MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY
BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE
PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE EAST
NORTHEAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EDT MON JUL 22 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S.
THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER
CENTRAL NORTH CAROLINA THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM MONDAY...
REST OF TODAY: VERY MOIST AIR MASS IN PLACE AS NOTED BY 12Z GSO/MHX
SOUNDINGS AND BLENDED TPW IMAGERY... WITH PW RANGING FROM 2.0-2.2
INCHES WEST TO EAST... ALTHOUGH VALUES ARE SLIGHTLY LOWER TO OUR
WEST. LATEST SURFACE ANALYSIS SHOWS THE NEARLY STATIONARY SYNOPTIC
FRONTAL ZONE FROM IA EAST ACROSS NRN IL/IN/OH TO PA/MA. A WEAK LOW
IS EVIDENT OVER SCENTRAL VA WITH TRAILING WEAK TROUGHING THROUGH
CENTRAL NC... AND A MORE PROMINENT LOW AND TROUGH OVER SRN IL/SE
MO/NW AR. THE LATTER FEATURE IS ASSOCIATED WITH A POTENT MID LEVEL
SHORTWAVE TROUGH THAT IS ON PACE TO APPROACH OUR AREA LATE TONIGHT.
ANOTHER UPPER LEVEL WAVE NOW OVER THE AL/GA BORDER IS EXPECTED TO
TRACK ACROSS FAR SRN AND SE NC THIS EVENING. MODELS ARE NOT IN GREAT
AGREEMENT ON THE TIMING AND EXTENT OF CONVECTION THIS AFTERNOON/
EVENING. THE 4KM WRF-ARW/WRF-NMM AND HRRR DEPICT JUST SCATTERED
COVERAGE IN THE EARLY AFTERNOON IN THE ERN CWA... WHERE THE CINH HAS
VANISHED AND WHERE MLCAPE HAS ALREADY CLIMBED NEAR 1000 J/KG. BUT
THE DEEP LAYER SHEAR IS QUITE POOR (UNDER 15 KTS) AND EXPECTED TO
REMAIN SO THROUGH THE DAY... NOT SUPPORTIVE OF STRONG ORGANIZED
CONVECTION. PW WILL ALSO BE DROPPING A BIT THIS AFTERNOON... AND THE
STRONG MISS VALLEY WAVE SHIFTING EASTWARD MAY HELP DEAMPLIFY THE
AL/GA WAVE AS IT CROSSES THE CAROLINAS. WILL ADJUST POPS A BIT
THROUGH THE AFTERNOON TO FOCUS THE BETTER COVERAGE (30-40%) IN THE
EAST... WHERE MOISTURE AND INSTABILITY IS EXPECTED TO BE BETTER
BENEATH WEAK UPPER-LEVEL DPVA... WITH LOWER POPS OF 20-30% IN THE
WRN CWA. LOCALLY HEAVY RAIN IS STILL POSSIBLE WITH WARM LAYERS
(LCL-0C) OF 3.5-3.8 KM... AND ANY ADDITIONAL RAIN IN AREAS THAT SAW
A LOT YESTERDAY (SUCH AS THE GREENSBORO AREA) COULD EASILY SEE QUICK
FLOODING TODAY. FREQUENT LIGHTNING IS STILL A SECONDARY CONCERN...
ALTHOUGH THE MARGINAL -10C TO -30C CAPE PEAKING AT 500 J/KG IS NOT
AS HIGH AS IN SOME OF THE PROLIFIC LIGHTNING EVENTS WE`VE HAD
RECENTLY. TEMP RISE SO FAR HAS BEEN GREATLY TEMPERED BY STUBBORN
STRATOCU OVER MUCH OF CENTRAL NC... WITH ONLY ERN/SRN SECTION SEEING
SOME HOLES IN THE CLOUDS. EXPECT THIS WILL START TO MIX OUT SHORTLY
(BASED ON PILOT REPORTS THAT THIS DECK IS 500-1000 FT THICK)... BUT
WITH THE DELAYED INSOLATION... WILL STILL NEED TO TRIM A FEW DEGREES
OFF HIGHS... GOING WITH 85-90. -GIH
WHILE BULK OF CONVECTION WILL DIMINISH IN THE EVENING WITH LOSS OF
HEATING...APPROACH OF THE MID-UPPER LEVEL TROUGH WILL LIKELY
MAINTAIN A FEW SHOWERS/STORMS INTO THE OVERNIGHT HOURS. CONTINUED
MUGGY TONIGHT WITH MIN TEMPS NEAR 70-LOWER 70S. -WSS
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 300 AM MONDAY...
EXPECT A CONTINUATION OF THE UNSETTLED WEATHER PATTERN TUESDAY DUE
TO PRESENCE OF MID-UPPER LEVEL TROUGH OVER THE CAROLINAS THOUGH
FOCUS MAY BE MORE IN THE EAST VERSUS WEST. SHORT TERM MODEL GUIDANCE
SUGGEST WESTERLY 850MB FLOW DEVELOPING LATE TODAY INTO TUESDAY WITH
A 850MB TROUGH CROSSING THE REGION TUESDAY AFTERNOON. RH CROSS
SECTION SUGGEST THE AIR MASS DRYING OUT ABOVE 700MB/10K FT DURING
THE COURSE OF THE AFTERNOON...ESPECIALLY WEST OF HIGHWAY 1. THE
DOWNSLOPE FLOW IN THE WAKE OF THIS SYSTEM AND AN AIR MASS NOT AS
MOIST MAY LIMIT/INHIBIT CONVECTIVE DEVELOPMENT IN THE WEST ON
TUESDAY. WITH TROUGH CROSSING THE EAST DURING MAX HEATING...STILL
EXPECT AT A MINIMUM 50 PERCENT COVERAGE. PRESENCE OF DRIER AIR ALOFT
MAY LEAD TO EVAPORATIVE COOLING IN VICINITY OF THUNDERSTORM
DOWNDRAFTS...LEADING TO STRONG/LOCALLY DAMAGING WINDS WITH THE
STRONGER CELLS. MAJORITY OF THE CONVECTION WILL DISSIPATE SHORTLY
AFTER SUNSET THOUGH THE APPROACH OF A SECONDARY TROUGH IN THE FLOW
ALOFT MAY TRIGGER ADDITIONAL ACTIVITY LATE TUESDAY NIGHT-EARLY
WEDNESDAY MORNING.
THE DRIER AIR MASS ALOFT SHOULD ALLOW FOR PERIODS OF PARTIAL
SUNSHINE. THIS MAY LEAD TO AFTERNOON TEMPS A COUPLE OF DEGREES
WARMER THAN TODAY. EXPECT MAX TEMPS NEAR 90 TO LOWER 90S AREAWIDE.
MIN TEMPS NEAR 70-LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
WEDNESDAY THROUGH THURSDAY:
THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO
UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF
LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS
THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH
CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY
NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY
BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC
STATES.
DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN
THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION
OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE
HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND
COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE
FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS
COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL
PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG
TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN
NC.
NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S
SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE.
FRIDAY THROUGH SUNDAY:
FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE...
WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL
DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW
ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING.
ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE
SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE
LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS
EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65
TO 70.
TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND
ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY
NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO
30 PERCENT.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 730 AM MONDAY...
A MOIST AIR MASS WILL REMAIN OVER CENTRAL NC THROUGH MID WEEK.
MEANWHILE AN UPPER LEVEL TROUGH WILL DRIFT SLOWLY EAST FROM THE TN
VALLEY TODAY TO THE CAROLINAS TUESDAY. THIS UPPER LEVEL FEATURE WILL
REMAIN OVER THE REGION THROUGH THURSDAY THEN WEAKEN/DISSIPATE.
DISTURBANCES ROTATING THROUGH THIS TROUGH...INTERACTING WITH THE
MOIST AIR MASS AND AFTERNOON HEATING...WILL TRIGGER
SCATTERED-NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY. CONVECTIVE
COVERAGE IS EXPECTED TO BE GREATEST IN THE LATE AFTERNOON THROUGH
THE EARLY EVENING HOURS THOUGH ISOLATED SHOWERS MAY OCCUR AT ANY
TIME. EXPECT MVFR/IFR CEILINGS AND MVFR VISIBILITIES IN VICINITY OF
THE SHOWERS AND STORMS. THIS SCENARIO SHOULD PLAY OUT EACH AFTERNOON
THROUGH WEDNESDAY WITH LESS COVERAGE EXPECTED THURSDAY AND FRIDAY.
DUE TO THE PRESENCE OF THE MOIST AIR...WIDESPREAD STRATUS AND
ASSOCIATED IFR CEILINGS WILL OCCUR EACH MORNING JUST PRIOR TO
DAYBREAK...CONTINUING UNTIL 11 AM OR NOON EACH DAY. POCKETS OF IFR
VISIBILITY DUE TO FOG MAY ALSO OCCUR. THE FOG SHOULD LIFT BY 9-10 AM
EACH DAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...CBL
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1047 AM CDT MON JUL 22 2013
.UPDATE...
ISSUED AT 1038 AM CDT MON JUL 22 2013
MAIN CHALLENGES TODAY ARE CLOUDS AND TEMPERATURES. COOL STRATUS
CLOUD DECK LIKELY TO BE MORE PERSISTENT TODAY THAN EARLIER
FORECAST. AS A RESULT OF MORE CLOUDS ALSO LOWERED TEMPERATURES
ABOUT 2 TO 3 DEGREES ACROSS THE NORTH AND CENTRAL. EXPECT SUNNY OR
MOSTLY SUNNY SKIES SOUTHWEST.
UPDATE ISSUED AT 655 AM CDT MON JUL 22 2013
MAIN PROBLEM FOR THE MORNING UPDATE WAS CLOUD COVER. EXPANSIVE
AREA OF STRATUS ACROSS EASTERN SASKATCHEWAN AND MANITOBA IS
SPILLING SOUTHWARD INTO NORTH DAKOTA. MOST MODELS ARE NOT
CAPTURING THE LOW LEVEL MOISTURE WELL. THE 10 UTC RAP WAS TOO
GENEROUS WITH ITS 925MB RH LAYER BUT DOES SEEM TO HAVE A GOOD
TREND ON DIMINISHING IT MID MORNING INTO EARLY AFTERNOON. USED A
BLEND OF THE RAP WITH CURRENT OBS AND COORDINATION WITH FGF TO
TAKE A SHOT AT CLOUD COVER DURING THE DAY. WITH ONLY A THIN LAYER
OF MOISTURE...THINK EVEN THE FAR EASTERN PORTIONS OF THE CWA
SHOULD SEE SOME AFTERNOON SUNSHINE. OTHERWISE NO SIGNIFICANT
CHANGES TO THE CURRENT FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT MON JUL 22 2013
HIGH BASED THUNDERSTORMS LATE THIS EVENING AND TONIGHT ACROSS
WESTERN NORTH DAKOTA CAPABLE OF STRONG WINDS WILL HIGHLIGHT THE
SHORT TERM FORECAST.
OVERALL...A MUCH QUIETER AND COOLER DAY ACROSS WESTERN AND CENTRAL
NORTH DAKOTA IS EXPECTED COMPARED TO SUNDAY. GIVEN GOOD MODEL
AGREEMENT OF SURFACE HIGH PRESSURE ACROSS MUCH OF NORTH
DAKOTA...AND LEE LOW PRESSURE ACROSS NORTHEAST WYOMING THROUGH
CENTRAL MONTANA...UTILIZED A BLEND OF THE 00 UTC GUIDANCE SUITE.
WITH WEAK NORTHERLY FLOW AND A MUCH COOLER AIRMASS IN
PLACE...HIGHS IN THE UPPER 60S ARE FORECAST ACROSS THE TURTLE
MOUNTAINS...TO THE 70S FOR MOST OTHER LOCATIONS ACROSS THE
AREA...WITH MID 80S FOR THE FAR SOUTHWEST WHERE LOW LEVEL THERMAL
FIELDS AND MIXING ARE EXPECTED TO BE GREATEST.
GIVEN THE GOOD PERFORMANCE OF THE 00 UTC 4KM WRF...AND THE
REMAINING HIGH RESOLUTION MODELS CONTAINED WITHIN THE 00 UTC SPC
STORM SCALE ENSEMBLE OF OPPORTUNITY...WILL FOLLOW CLOSELY TO THESE
SOLUTIONS FOR THE CONVECTIVE POTENTIAL THIS EVENING AND TONIGHT
ACROSS THE WEST. EXPECT SURFACE BASE CONVECTIVE DEVELOPMENT ALONG
THE AFOREMENTIONED LEE TROUGH ACROSS MONTANA THIS AFTERNOON WITH THE
APPROACH OF THE SHORTWAVE CURRENTLY ACROSS WASHINGTON STATE.
STORMS ARE FORECAST TO PROPAGATE SOUTHEAST INTO WESTERN NORTH
DAKOTA BETWEEN 00-03 UTC. THE 00 UTC NAM/GFS BUFR SOUNDINGS DEPICT
INVERTED V PROFILES ACROSS THE WEST THIS EVENING. WHILE OVERALL
INSTABILITY IS MARGINAL FOR SEVERE CONVECTION...AMPLE DEEP LAYER
SHEAR NEAR 40 KTS AND HIGH BASES NEAR 750-700 MB SUGGEST A LOW END
THREAT FOR STRONG WINDS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 357 AM CDT MON JUL 22 2013
AN ACTIVE PATTERN WILL CONTINUE THROUGH THE EXTENDED PERIOD. WE
BEGIN WITH A NORTHWEST FLOW ALOFT AND TRANSITION TO A SOUTHWEST
UPPER FLOW LATE IN THE EXTENDED PERIOD. GENERAL AGREEMENT BETWEEN
DETERMINISTIC MODELS IN LARGE SCALE FLOW AND WILL UTILIZE A MODEL
BLEND WITH PERSISTENCE.
ON TUESDAY...HIGH PRESSURE OVER THE EASTERN DAKOTAS WITH UPPER LEVEL
JET ENERGY INDUCING SCATTERED SHOWERS AND THUNDERSTORMS OVER WESTERN
NORTH DAKOTA EARLY TUESDAY. THIS SHOULD TRANSLATE INTO SOUTH DAKOTA
DURING THE MORNING. MODELS INDICATE ANOTHER IMPULSE MOVING THROUGH
SOUTHERN CANADA INDUCING SURFACE LOW PRESSURE OVER EASTERN MONTANA
BY TUESDAY AFTERNOON. INCREASING WARM ADVECTION AHEAD OF THE LOW
COMBINED WITH THE AFOREMENTIONED IMPULSE WILL PRODUCE STEEPENING
LAPSE RATES AND A VEERING WIND PROFILE SUPPORTIVE OF STRONG TO
SEVERE STORMS TRANSLATING NORTHWEST TO SOUTHEAST ACROSS THE LOCAL
AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.
PERHAPS SOME LINGERING CONVECTION IN THE FAR EAST WEDNESDAY BUT FOR
THE MOST PART WEDNESDAY IS EXPECTED TO BE DRY AS SURFACE HIGH
PRESSURE TRACKS ACROSS THE AREA. THURSDAY IS ALSO EXPECTED TO BE
RELATIVELY QUIET BUT UPPER LEVEL JET ENERGY REMAINING OVER THE AREA
COMBINED WITH DIURNAL HEATING WILL STILL SUPPORT ISOLATED TO
SCATTERED THUNDERSTORMS.
A MORE SIGNIFICANT WAVE MOVES THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS.
UPPER LEVEL RIDGING BUILDS OVER THE AREA ON SATURDAY. THE ECMWF IS
QUICKER TO BRING THE RIDGE INTO THE AREA RESULTING IN A DRY FORECAST
SATURDAY. THE GFS KEEPS AN AREA OF CONVECTION OVER THE WEST AND
SOUTH CENTRAL THROUGH MIDDAY BEFORE DRYING THINGS OUT LATER IN THE
DAY. THE ECMWF IS ALSO QUICKER TO BREAK DOWN THE RIDGE AND INTRODUCE
SOUTHWEST FLOW OVER THE AREA BY SUNDAY AFTERNOON...WHILE THE GFS
KEEPS THE LOCAL AREA DRY ON SUNDAY WITH ANY CONVECTION HOLDING OFF
UNTIL LATE SUNDAY NIGHT IN THE FAR WEST.
ALL IN ALL A RATHER ACTIVE PATTERN WITH SEASONABLE TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1038 AM CDT MON JUL 22 2013
AT 10 AM CDT...SURFACE HIGH PRESSURE OVER SASKATCHEWAN AND
MANITOBA WAS BUILDING SOUTH INTO THE NORTHERN PLAINS. COOL
STRATO-CU LAYER HAS EXTENDED ACROSS ALL BUT THE SOUTHWEST. AM NOW
MORE PESSIMISTIC ON THE EVENTUAL BREAKUP OF THE CLOUD DECK BY LATE
THIS MORNING. EXTENDED THE CLOUDS THROUGH THE EARLY TO MID
AFTERNOON. MVFR CONDITIONS FROM KMOT-KBIS-KJMS THROUGH 20Z...THEN
IMPROVING TO VFR. KDIK SHOULD REMAIN VFR...WHILE KISN WILL BE IN
THE EDGE...BECOMING VFR A LITTLE EARLIER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
656 AM CDT MON JUL 22 2013
.UPDATE...
ISSUED AT 655 AM CDT MON JUL 22 2013
MAIN PROBLEM FOR THE MORNING UPDATE WAS CLOUD COVER. EXPANSIVE
AREA OF STRATUS ACROSS EASTERN SASKATCHEWAN AND MANITOBA IS
SPILLING SOUTHWARD INTO NORTH DAKOTA. MOST MODELS ARE NOT
CAPTURING THE LOW LEVEL MOISTURE WELL. THE 10 UTC RAP WAS TOO
GENEROUS WITH ITS 925MB RH LAYER BUT DOES SEEM TO HAVE A GOOD
TREND ON DIMINISHING IT MID MORNING INTO EARLY AFTERNOON. USED A
BLEND OF THE RAP WITH CURRENT OBS AND COORDINATION WITH FGF TO
TAKE A SHOT AT CLOUD COVER DURING THE DAY. WITH ONLY A THIN LAYER
OF MOISTURE...THINK EVEN THE FAR EASTERN PORTIONS OF THE CWA
SHOULD SEE SOME AFTERNOON SUNSHINE. OTHERWISE NO SIGNIFICANT
CHANGES TO THE CURRENT FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT MON JUL 22 2013
HIGH BASED THUNDERSTORMS LATE THIS EVENING AND TONIGHT ACROSS
WESTERN NORTH DAKOTA CAPABLE OF STRONG WINDS WILL HIGHLIGHT THE
SHORT TERM FORECAST.
OVERALL...A MUCH QUIETER AND COOLER DAY ACROSS WESTERN AND CENTRAL
NORTH DAKOTA IS EXPECTED COMPARED TO SUNDAY. GIVEN GOOD MODEL
AGREEMENT OF SURFACE HIGH PRESSURE ACROSS MUCH OF NORTH
DAKOTA...AND LEE LOW PRESSURE ACROSS NORTHEAST WYOMING THROUGH
CENTRAL MONTANA...UTILIZED A BLEND OF THE 00 UTC GUIDANCE SUITE.
WITH WEAK NORTHERLY FLOW AND A MUCH COOLER AIRMASS IN
PLACE...HIGHS IN THE UPPER 60S ARE FORECAST ACROSS THE TURTLE
MOUNTAINS...TO THE 70S FOR MOST OTHER LOCATIONS ACROSS THE
AREA...WITH MID 80S FOR THE FAR SOUTHWEST WHERE LOW LEVEL THERMAL
FIELDS AND MIXING ARE EXPECTED TO BE GREATEST.
GIVEN THE GOOD PERFORMANCE OF THE 00 UTC 4KM WRF...AND THE
REMAINING HIGH RESOLUTION MODELS CONTAINED WITHIN THE 00 UTC SPC
STORM SCALE ENSEMBLE OF OPPORTUNITY...WILL FOLLOW CLOSELY TO THESE
SOLUTIONS FOR THE CONVECTIVE POTENTIAL THIS EVENING AND TONIGHT
ACROSS THE WEST. EXPECT SURFACE BASE CONVECTIVE DEVELOPMENT ALONG
THE AFOREMENTIONED LEE TROUGH ACROSS MONTANA THIS AFTERNOON WITH THE
APPROACH OF THE SHORTWAVE CURRENTLY ACROSS WASHINGTON STATE.
STORMS ARE FORECAST TO PROPAGATE SOUTHEAST INTO WESTERN NORTH
DAKOTA BETWEEN 00-03 UTC. THE 00 UTC NAM/GFS BUFR SOUNDINGS DEPICT
INVERTED V PROFILES ACROSS THE WEST THIS EVENING. WHILE OVERALL
INSTABILITY IS MARGINAL FOR SEVERE CONVECTION...AMPLE DEEP LAYER
SHEAR NEAR 40 KTS AND HIGH BASES NEAR 750-700 MB SUGGEST A LOW END
THREAT FOR STRONG WINDS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 357 AM CDT MON JUL 22 2013
AN ACTIVE PATTERN WILL CONTINUE THROUGH THE EXTENDED PERIOD. WE
BEGIN WITH A NORTHWEST FLOW ALOFT AND TRANSITION TO A SOUTHWEST
UPPER FLOW LATE IN THE EXTENDED PERIOD. GENERAL AGREEMENT BETWEEN
DETERMINISTIC MODELS IN LARGE SCALE FLOW AND WILL UTILIZE A MODEL
BLEND WITH PERSISTENCE.
ON TUESDAY...HIGH PRESSURE OVER THE EASTERN DAKOTAS WITH UPPER LEVEL
JET ENERGY INDUCING SCATTERED SHOWERS AND THUNDERSTORMS OVER WESTERN
NORTH DAKOTA EARLY TUESDAY. THIS SHOULD TRANSLATE INTO SOUTH DAKOTA
DURING THE MORNING. MODELS INDICATE ANOTHER IMPULSE MOVING THROUGH
SOUTHERN CANADA INDUCING SURFACE LOW PRESSURE OVER EASTERN MONTANA
BY TUESDAY AFTERNOON. INCREASING WARM ADVECTION AHEAD OF THE LOW
COMBINED WITH THE AFOREMENTIONED IMPULSE WILL PRODUCE STEEPENING
LAPSE RATES AND A VEERING WIND PROFILE SUPPORTIVE OF STRONG TO
SEVERE STORMS TRANSLATING NORTHWEST TO SOUTHEAST ACROSS THE LOCAL
AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.
PERHAPS SOME LINGERING CONVECTION IN THE FAR EAST WEDNESDAY BUT FOR
THE MOST PART WEDNESDAY IS EXPECTED TO BE DRY AS SURFACE HIGH
PRESSURE TRACKS ACROSS THE AREA. THURSDAY IS ALSO EXPECTED TO BE
RELATIVELY QUIET BUT UPPER LEVEL JET ENERGY REMAINING OVER THE AREA
COMBINED WITH DIURNAL HEATING WILL STILL SUPPORT ISOLATED TO
SCATTERED THUNDERSTORMS.
A MORE SIGNIFICANT WAVE MOVES THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS.
UPPER LEVEL RIDGING BUILDS OVER THE AREA ON SATURDAY. THE ECMWF IS
QUICKER TO BRING THE RIDGE INTO THE AREA RESULTING IN A DRY FORECAST
SATURDAY. THE GFS KEEPS AN AREA OF CONVECTION OVER THE WEST AND
SOUTH CENTRAL THROUGH MIDDAY BEFORE DRYING THINGS OUT LATER IN THE
DAY. THE ECMWF IS ALSO QUICKER TO BREAK DOWN THE RIDGE AND INTRODUCE
SOUTHWEST FLOW OVER THE AREA BY SUNDAY AFTERNOON...WHILE THE GFS
KEEPS THE LOCAL AREA DRY ON SUNDAY WITH ANY CONVECTION HOLDING OFF
UNTIL LATE SUNDAY NIGHT IN THE FAR WEST.
ALL IN ALL A RATHER ACTIVE PATTERN WITH SEASONABLE TEMPERATURES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 655 AM CDT MON JUL 22 2013
MVFR STRATUS CONTINUES TO SPREAD ACROSS NORTHWEST AND CENTRAL NORTH
DAKOTA AND WILL IMPACT KMOT AND KISN THROUGH AT LEAST 15
UTC...BEFORE BEGINNING TO LIFT AND SCATTER. THE STRATUS WILL
LIKELY IMPACT KBIS AND KJMS DURING THIS TIMEFRAME AS
WELL...HOWEVER...UNCERTAINTY IS HIGHER HERE AS THE STRATUS FIELD
SHOULD NOT BE AS WIDESPREAD NEAR THESE TERMINALS. THERE IS A
CHANCE OF THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA
TONIGHT...HOWEVER...DUE TO UNCERTAINTY IN COVERAGE...WILL LEAVE
THE MENTION OUT OF THE KISN AND KDIK TAFS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1118 AM EDT MON JUL 22 2013
.SYNOPSIS...
SFC FRONT STALLING JUST WEST TO EAST ACROSS WEST VIRGINIA NORTHERN
PANHANDLE. MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO
WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
1100 AM UPDATE...
COMPLICATED FCST SHAPING UP FOR THIS AFTN THRU TONIGHT. WILL BE
TRACKING A COUPLE POTENT UPR LVL SYS...THE FIRST OF WHICH
CURRENTLY MOVING THRU E OH AND SHOULD BE OUT OF SE OH BY 16Z. THE
SECOND LOCATED ACROSS IN AND KY...WITH A MESO VORTEX APPENDAGE
MOVING ACROSS S KY. USED LATEST RUC AND HRRR FOR TIMING AND
PLACEMENT OF POPS WITH THIS SECOND SYS WITH HVY SHRA MOVING BACK
INTO NE KY AND SE OH NEXT FEW HRS AND INTO S WV/SW VA BY 21Z. HAVE
SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS TRYING TO SCT OUT E OH OH
RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON
THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES TDY INTO EARLY
THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON
EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT.
UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING
IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF
AREA AFTER 09Z WITH PCPN THREAT DIMINISHING.
PREVIOUS DISCUSSION BELOW...
WATER VAPOR IMAGES INDICATE UPPER LOW SPINNING ACROSS SOUTHERN
IL...MOVING EAST INTO THE KY AND THE OH VALLEY TODAY.
ALTHOUGH THE SFC FRONT IS SUGGESTED TO REMAIN STATIONARY NORTH OF
THE AREA...A POSITIVELY TILTED SHORTWAVES AT H5 WILL APPROACH
FROM THE WEST AND NORTHWEST TO INTERACT WITH ABUNDANT LOW LEVEL
MOISTURE THIS AFTERNOON TO PRODUCE SCATTERED TO NUMEROUS SHOWERS
AND THUNDERSTORMS INTO THE EVENING HOURS. IN FACT...THE NAM SHOWS
A H500 SHORTWAVE WITH VORTICITY MAX DOWNSTREAM EAST OF THE TROUGH
JUST EAST OF SOUTHEAST OH BY 12Z TODAY. ANOTHER EMBEDDED BUT
WEAKER VORT MAX IS EVIDENT UPSTREAM THE TROUGH...WHICH WILL MAKE
IT DIG SOUTH INTO WV AND THE APPALACHIANS TONIGHT. THE NAM MODEL
SHOW A BUBBLE OF PWATS EXCEEDING 2 INCHES MOVING INTO SOUTHEAST OH
BY 15Z TODAY...AND SPREADING NORTHEAST ACROSS SOUTHEAST OH AND
PERIOD OF WV THROUGH 00Z TUESDAY. THE NAM...CMC...AND HRRR
SUGGEST THAT OUR NORTHWEST QUADRANT WILL RECEIVE THE BEST FORCING
DURING THE LATE AFTERNOON...AND ANOTHER PIECE OF ENERGY PASSING
ACROSS THE SOUTHERN COALFIELDS AND CENTRAL MOUNTAINS THROUGH
TONIGHT.
THESE FEATURES COULD ENHANCED CONVECTION DEVELOPMENT OVER THE
HIGHER ELEVATIONS...AND ACROSS SOUTHEAST OH AND NORTHERN PORTIONS
OF WEST VIRGINIA. THEREFORE...ADJUSTED POPS...HAVING SLIGHT CHANCE
POPS IN THE MORNING...AS THE BULK OF PCPN WILL FALL OVER CENTRAL
OH. THEN...GRADUALLY INCREASE POPS TO LIKELY THIS AFTERNOON AND
CATEGORICAL BY LATE AFTERNOON AND EVENING.
USED A BLEND BETWEEN THE BIAS CORRECTED SREF AND GMOS RAW FOR
TEMPERATURES THROUGH THE PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
EXCEPT FOR THE NAM/SREF SUITE OF MODELS WHICH ARE SLOW OUTLIERS
THERE IS GROWING AGREEMENT AMONG THE MODELS OF A FASTER
PROGRESSION OF THE COLD FRONT TUESDAY NIGHT...AND OF A QUITE WEAK
SECONDARY FRONT WEDNESDAY.
FIRST...EXPECT A RAPID DECREASE IN CONVECTION TUESDAY AS AN UPPER
DISTURBANCE EXITS AND TAKES MUCH OF THE RICH MOISTURE WITH IT.
AGAIN...THE NAM IS A VERY SLOW OUTLIER EXITING THIS SYSTEM AND WAS
NOT USED. WILL PAINT HIGH POPS EARLY IN MOUNTAINS BUT DECREASE THAT
DURING TUESDAY MORNING. WILL KEEP LOWER POPS TUESDAY AFTERNOON WITH
REMAINING LOW LEVEL MOISTURE AND HEATING TO DESTABILIZE THE
ATMOSPHERE WELL AHEAD OF THE AFOREMENTIONED COLD FRONT...ESPECIALLY
MOUNTAINS WITH AN ELEVATED HEAT SOURCE.
WILL RAMP POPS UP AGAIN TUESDAY NIGHT WITH THE FRONT...GOING LIKELY
FOR AN ORGANIZED BAND OF CONVECTION ALONG THE FRONT. HOWEVER...LESS
RISK OF WATER PROBLEMS WITH THIS FEATURE AS PW`S WILL BE MUCH LESS
THAN WE ARE CURRENTLY EXPERIENCING. WILL KEEP LOW POPS IN FOR MAINLY
WEDNESDAY AFTERNOON AS THE SECONDARY FRONT DROPS SOUTHEASTWARD
ACROSS THE AREA...MOSTLY IN MOUNTAINS.
HIGH PRESSURE FINALLY BUILDS IN FOR THURSDAY WITH DRIER AND COOLER
AIR BECOMING ESTABLISHED. STILL LINGER JUST A LOW CHANCE POP MOSTLY
MOUNTAINS FOR AN AFTERNOON SHOWER PER SQUEEZING OUT ANY LINGERING LOW
LEVEL MOISTURE WITH UPSLOPE FLOW AND MODEST COLD ADVECTION ALOFT.
LOOK FOR A MODEST COOLING TREND THIS PERIOD...BUT A SIGNIFICANT
DRYING OUT. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
STILL TRYING TO BRING DRIER AIR THURSDAY INTO FRIDAY. DEEPENING
500 MB TROF OVER EASTERN CANADA MAY PULL ANOTHER DISTURBANCES SE
ON SATURDAY.
NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
IFR/LIFR UNDER DENSE FOG POSSIBLE OVER AREAS THAT RECEIVED RAIN
YESTERDAYS AND WHERE SKY CLEARS. EXPECT THIS CONDITIONS MAINLY AT
CRW...CKB...NEARBY BKW AND PKB. PLENTY OF CLOUDINESS IS EVIDENT IN
IR SATELLITE IMAGES ASSOCIATED WITH CONVECTION OVER NORTH CENTRAL
KY...INTO SOUTHERN OH. H7 FLOW SEEMS TO TAKE THESE CLOUDS NORTH
NORTHEAST. SOME CLOUDS WILL FILTER INTO SOUTHEAST OH OVERNIGHT
WHILE OTHER PATCHES OF CLOUDS DISSIPATE ALLOWING RADIATIONAL
COOLING FOR FOG FORMATION.
BY 13Z MONDAY...ANY IFR FOG IS EXPECTED TO LIFT INTO MVFR/VFR
CONDITIONS THROUGH GREAT PART OF THE MORNING.
MODELS INSIST ON ROUNDS OF SHOWERS OR STORMS DEVELOPING EARLY
MORNING ACROSS SOUTHEAST OH...TO MOVE NORTHEAST POSSIBLY AFFECTING
PKB THROUGH 15Z. THEN...THE NAM/GFS MODELS BRING A STRONG
SHORTWAVE BY 18Z MONDAY JUST WEST OF SOUTHEAST OH. THIS FEATURE
WILL ENHANCE CONVECTION MONDAY AFTERNOON FOR IFR CONDITIONS ALONG
THE STRONGER SHOWERS.
SHOWERS AND THUNDERSTORMS ARE LIKELY TO OVERSPREAD THE SOUTHERN
TAF SITES BY MONDAY AFTERNOON AND EVENING. THIS WILL BRING
WIDESPREAD MVFR CONDITIONS MON WITH IFR CONDITIONS IN THE HEAVIER
RAINFALL.
SFC FLOW WILL REMAIN CALM OR LIGHT AND VARIABLE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING/DENSITY OF FOG MAY VARY OVERNIGHT
DEPENDING ON CLOUD COVER. TIMING OF RAINFALL AND ASSOCIATED MVFR OR
WORSE CONDITIONS MAY VARY EARLY MORNING TO LATE AFTERNOON MONDAY.
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.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H L L L L L L M M M
HTS CONSISTENCY M M M L M L L L M M M M
BKW CONSISTENCY H H H H M L L L L M M M
EKN CONSISTENCY H M H H H H M M M M M M
PKB CONSISTENCY M H H H H M M M M M M M
CKB CONSISTENCY H H H H H H H M M M M M
AFTER 12Z TUESDAY...
WIDESPREAD IFR TO LIFR POST-RAIN FOG AND/OR LOW CEILINGS OVERNIGHT
MON NT INTO TUE MORNING. IFR ALSO POSSIBLE IN VALLEY FOG OR LOW
CEILINGS EACH MORNING WED THROUGH THROUGH FRI.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...ARJ/JMV/MZ
NEAR TERM...ARJ/30
SHORT TERM...JMV
LONG TERM...KTB
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1022 AM CDT MON JUL 22 2013
.DISCUSSION...
HAVE UPDATED ZONES AND GRIDS TO REDUCE POPS OVER THE NORTHWEST.
RAIN IS BEGINNING TO TAPER OFF OVER THE NORTHWEST AND EXPECT THIS
TREND WILL CONTINUE.
BOYD
&&
.PREV DISCUSSION... /ISSUED 922 AM CDT MON JUL 22 2013/
MESOSCALE UPDATE...
ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS
HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE
NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL
SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN
ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND
UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE
BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE
AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT
SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON.
BOYD
PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/
UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S.
AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH
MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID
STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF
OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH
SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS
EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG
TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING.
PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/
DISCUSSION...
THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN
RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE
WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF
DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE
MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN
FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR
THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH
VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL
REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT
FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY
THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE
NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS
AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW
WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST
15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO
MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT
PERIOD OF TIME.
THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS
PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY
LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY
TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE
HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM
OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES
WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD.
WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND
FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP
MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS.
WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF
OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND
UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI
VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS
STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN
REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT
AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS.
UNGER
AVIATION...06Z TAF DISCUSSION.
UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST
OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA
TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY
IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY
SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE
CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR
TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED
AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD
HANG ON.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 87 72 91 72 / 90 30 50 30
CLARKSVILLE 86 70 91 70 / 40 30 50 30
CROSSVILLE 80 68 84 68 / 90 40 40 30
COLUMBIA 87 72 90 72 / 90 30 50 40
LAWRENCEBURG 87 71 89 71 / 90 40 50 40
WAVERLY 87 71 92 71 / 50 30 50 30
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
922 AM CDT MON JUL 22 2013
.MESOSCALE UPDATE...
ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS
HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE
NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL
SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN
ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND
UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE
BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE
AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT
SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON.
BOYD
&&
.PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/
UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S.
AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH
MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID
STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF
OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH
SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS
EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG
TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING.
PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/
DISCUSSION...
THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN
RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE
WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF
DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE
MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN
FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR
THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH
VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL
REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT
FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY
THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE
NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS
AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW
WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST
15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO
MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT
PERIOD OF TIME.
THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS
PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY
LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY
TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE
HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM
OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES
WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD.
WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND
FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP
MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS.
WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF
OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND
UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI
VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS
STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN
REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT
AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS.
UNGER
AVIATION...06Z TAF DISCUSSION.
UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST
OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA
TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY
IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY
SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE
CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR
TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED
AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD
HANG ON.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
520 AM CDT MON JUL 22 2013
.UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S.
&&
.AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH
MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID
STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF
OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH
SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS
EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG
TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING.
&&
.PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/
DISCUSSION...
THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN
RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE
WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF
DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE
MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN
FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR
THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH
VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL
REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT
FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY
THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE
NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS
AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW
WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST
15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO
MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT
PERIOD OF TIME.
THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS
PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY
LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY
TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE
HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM
OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES
WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD.
WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND
FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP
MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS.
WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF
OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND
UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI
VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS
STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN
REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT
AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS.
UNGER
AVIATION...06Z TAF DISCUSSION.
UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST
OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA
TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY
IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY
SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE
CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR
TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED
AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD
HANG ON.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ROSE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
623 AM CDT MON JUL 22 2013
.MESOSCALE DISCUSSION...
ISSUED AT 623 AM CDT MON JUL 22 2013
19.05Z THROUGH 19.09Z HRRR MODEL FORECASTS ARE STAYING EXTREMELY
CONSISTENT WITH DEVELOPMENT OF CONVECTION ALONG THE APPROACHING
COLD FRONT THIS AFTERNOON. CONVECTION FIRES IN SOUTHEAST MN AND
NORTHWEST WI BETWEEN 18-20Z...THEN MARCHES SOUTHEAST THROUGH THE
FORECAST AREA...LIKELY EXITING BY 00Z. AN INTERESTING SIGNAL
SHOWING UP IS A SPLIT IN THE CONVECTION AREAS ALONG THE FRONT. ONE
AREA TRACKS MORE ACROSS CENTRAL/NORTHERN WI...CLOSER TO THE
DYNAMICS ASSOCIATED WITH THE SHORTWAVE TROUGH CROSSING LAKE
SUPERIOR AND NORTHERN ONTARIO. THE OTHER AREA DROPS DOWN THROUGH
EASTERN IOWA...FOLLOWING THE HIGHER INSTABILITY. THIS SIGNAL
SHOWS UP TOO IN THE 22.06Z NAM...OUR LOCAL WRF RUN...THE 22.00Z
HIRES ARW AND NSSL WRF. WE WILL SEE IF THIS HAPPENS IN REALITY.
SPECIFIC STORM SCALE DATA FROM THE HRRR DOES INDICATE POTENTIAL
FOR SOME DISCRETE STORM CELLS UPON INITIATION...EVENTUALLY TURNING
INTO LINEAR STRUCTURES. THUS...INITIAL STORMS COULD POSE BOTH A
LARGE HAIL AND DAMAGING WIND CONCERN...FOLLOWED BY DAMAGING WINDS
THEREAFTER. GOING HAZARD CONCERNS IN THE HWO AND OTHER SERVICES
REMAIN ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE
THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING.
LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN
MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE
OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG
THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN
NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING
SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON.
THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND
BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF
MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS
TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS
AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE
AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500
TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW
SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM
BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST
OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED
PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE
CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR
ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS.
CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS
AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE
MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN
CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800
MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO
DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS
AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE
CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON.
ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE
TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED
TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE
WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING
OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT
SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL
GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE
DAMAGING WINDS.
THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE
19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST
MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING
ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN
THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE
FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP
THIS AFTERNOON.
HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER
TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB
INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE
MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS
EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS
WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT
LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS.
OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR
WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 335 AM CDT MON JUL 22 2013
SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON
TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES.
NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS
FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE
LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND
80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY
OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND
CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG
DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL
WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL
FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK
RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF
THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION
LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW
ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE
AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF
ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE
WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE
STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY.
PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK
SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE
AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90
DURING THE DAY ON SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 623 AM CDT MON JUL 22 2013
SOUTHERLY FLOW AHEAD OF A COLD FRONT IN WESTERN MINNESOTA HAS BEEN
BRINGING UP MORE MOISTURE INTO THE REGION AND TAF SITES. THIS
MOISTURE HAS MANIFESTED ITSELF AS LIFR TO IFR STRATUS...WITH EVEN
SOME FOG RANGING FROM VLIFR TO IFR AT RST. CEILINGS AND
VISIBILITIES WILL GRADUALLY RISE THROUGH MORNING DUE TO DAYTIME
MIXING...WITH BOTH TAF SITES LIKELY VFR BY 16Z.
DURING THE AFTERNOON...THE COLD FRONT IS EXPECTED TO MOVE THROUGH
THE TAF SITES. THUNDERSTORMS LOOK LIKELY TO ACCOMPANY THE
FRONT...SO IT IS JUST A MATTER OF TIMING. BASED ON A CONSENSUS OF
HIGH RESOLUTION MODEL FORECASTS...SPED UP THE TIMING FROM THE 06Z
TAFS...IMPACTING RST BETWEEN 19-22Z AND LSE BETWEEN 20-23Z. ITS
POSSIBLE THE STORMS COULD EXIT THE TAF SITES A LITTLE SOONER.
VISIBILITIES AND CEILING MAY FALL TO MVFR OR PERHAPS EVEN LOWER
BRIEFLY. ADDITIONALLY...POTENTIAL EXISTS FOR THE STORMS TO BRING
STRONG TO DAMAGING WIND GUSTS AND LARGE HAIL. CONFIDENCE IS TOO
LOW TO MENTION ANY SEVERE POTENTIAL DIRECTLY IN THE TAFS AT THIS
TIME. VFR CONDITIONS WITH WINDS SHIFTING TO THE NORTHWEST ARE
EXPECTED BEHIND THE FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
215 PM EDT MON JUL 22 2013
.UPDATE...
ISSUED AT 200 PM EDT MON JUL 22 2013
UPDATED THE FORECAST TO BETTER TIME THE RAIN BAND THROUGH THE CWA AND
ALLOW FOR MORE CONVECTION TO DEVELOP IN ITS WAKE. ALSO...TWEAKED THE
TEMP AND DEWPOINT TRACES PER THE LATEST OBS AND TRENDS...AS WELL AS
TOUCHED UP FORECAST HIGHS. UPDATED GRIDS HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS ALONG WITH A FRESHENED ZFP.
UPDATE ISSUED AT 1025 AM EDT MON JUL 22 2013
13Z SFC ANALYSIS SHOWS A DEVELOPING AREA OF LOW PRESSURE MOVING INTO
THE OHIO VALLEY. THIS DEVELOPMENT IS OCCURRING DUE TO AN INBOUND AND
SHARPENING 500 MB SHORT WAVE THAT WILL CROSS NORTHERN KENTUCKY
LATER TODAY. AS SUCH...IT IS ALSO BRINGING WITH IT A LARGE CLUSTER OF
MAINLY MODERATE SHOWERS ALONG WITH A COUPLE OF EMBEDDED
THUNDERSTORMS. THE RAIN AREA IS POISED TO ENTER OUR CWA AND
PROGRESS FROM WEST TO EAST THROUGH THE REST OF THE MORNING. THE
LATEST HRRR DOES SHOW THIS AREA BREAKING UP TOWARD NOON AND MORE
SCATTERED CONVECTION DEVELOPING THROUGHOUT EAST KENTUCKY...
THEREAFTER. EXPECT THIS SECONDARY CONVECTION...TAPPING INTO HIGH PW
AIR IN PLACE...TO HAVE THE BEST CHANCE OF PRODUCING EXCESSIVE
RAINS...TRAINING...AND THE POTENTIAL FOR LOCALIZED FLASH FLOODING.
HAVE UPDATED THE GRIDS TO REFLECT THIS TYPE OF EVOLUTION TO THE
POPS...WX...AND QPF. ALSO...BUMPED UP TEMPS IN THE EAST A NOTCH DUE
TO A DECENT SUNNY PATCH MOVING THROUGH ATTM AHEAD OF THE INBOUND MASS
OF SHOWERS. MEANWHILE...TOOK DOWN THE MAX TEMPS IN THE WEST A TAD FOR
THE OPPOSITE REASON. OTHERWISE...THE THREAT FOR DOWNPOURS LOOKS GOOD
FOR MOST OF THE REGION SO WILL CONTINUE THE FFA AND MENTION OF
LOCALLY HEAVY RAIN IN THE ZONES/HWO THROUGH THE EVENING. FOR
TONIGHT...WILL HAVE TO LOOK CLOSELY AT THE POTENTIAL FOR DENSE FOG
IF WE MANAGE TO GET MUCH CLEARING AFTER THE RAINS OF TODAY. UPDATES
HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 753 AM EDT MON JUL 22 2013
UPSTREAM RADARS SHOW A LARGE CLUSTER OF SHOWERS AND STORMS MAKING A
BEELINE TOWARD EAST KENTUCKY. AS A RESULT...WE NUDGED POPS UP INTO
THE CATEGORICAL RANGE FOR ALL BUT OUR EASTERNMOST COUNTIES AS RECENT
HRRR RUNS SHOW THE SHOWERS BREAKING UP SOME AS THEY HEAD EAST OF JKL.
UPDATE ISSUED AT 655 AM EDT MON JUL 22 2013
MODIFIED THE FORECAST GRIDS TO REFLECT SLOWER ONSET OF PRECIPITATION
EARLY THIS MORNING. ALSO ISSUED AN UPDATE TO THE FLASH FLOOD WATCH.
THE NEW ZONES WILL BE ISSUED SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 310 AM EDT MON JUL 22 2013
MODELS IN PRETTY GOOD AGREEMENT ON THE OVERALL WEATHER PATTERN FOR
THE NEXT COUPLE OF DAY. CONSENSUS VIEW IS FOR WIDESPREAD SHOWERS AND
STORMS TO DEVELOP EARLY THIS MORNING AND PERSIST THROUGH THE END OF
THE DAY ON TUESDAY. THE PRIMARY CONCERN WILL BE LOCALLY HEAVY
RAINFALL AND FLOODING. WITH A DEEP LAYER OF MOISTURE IN THE
ATMOSPHERE AND WEAK MIDDLE AND UPPER LEVEL WINDS...ANY STORMS THAT
FORM WILL BE SLOW MOVING AND WILL HAVE THE POTENTIAL PRODUCE HEAVY
RAINFALL OVER VERY LOCALIZED AREAS...WHICH COULD LEAD TO FLASH
FLOODING. HIGH TEMPERATURES TODAY AND TOMORROW WILL BE SLIGHTLY BELOW
NORMAL...DUE TO THE INFLUENCE OF WIDESPREAD CLOUD COVER AND SHOWER
AND STORM ACTIVITY. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL OF
EASTERN KENTUCKY THROUGH MONDAY EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON JUL 22 2013
LONGWAVE TROUGH NOW BECOMING ESTABLISHED OVER THE EASTERN U.S. WILL
REMAIN IN PLACE THROUGH THE LONG TERM PERIOD. AT THE SURFACE...A
COLD FRONT WILL SLIP TO OUR SOUTH TUESDAY NIGHT AND WEDNESDAY WITH
HIGH PRESSURE BUILDING IN BEHIND. WHILE THE DEEPER MOISTURE WILL BE
TO OUR SOUTH BY TUESDAY NIGHT...THE FRONT WILL LIKELY KICK OFF
ISOLATED TO SCATTERED SHOWERS/STORMS AS IT PASSES. THE HIGH PRESSURE
SYSTEM WILL THEN USHER IN A MUCH DRIER AIR MASS FOR THURSDAY AND
FRIDAY. IN FACT...IT APPEARS DEWPOINTS MAY EVEN TUMBLE AS LOW AS THE
UPPER 50S BY THURSDAY AFTERNOON...WHICH WILL FEEL VERY NICE AFTER
THE RECENT PROLONGED BOUT OF 70 DEGREE DEWPOINTS.
FORECASTER CONFIDENCE THEN FALLS AS WE HEAD INTO THE WEEKEND. THE
UPPER LEVEL TROUGH WILL DIG BACK IN AFTER A BRIEF RELAXATION FORCING
A SURFACE FRONT SOUTHWARD INTO THE OHIO VALLEY. THE 22/00Z ECMWF
WANTS TO HOLD A PIECE OF THE UPPER TROUGH BACK OVER THE PLAINS...
WHILE THE 22/00Z GFS/GEM/UKMET DO NOT. THIS RESULTS IN A WETTER
SOLUTION IN THE GFS/GEM/UKMET MODELS WHILE THE ECMWF IS SLOWER TO
BRING IN ANY PRECIP. AS SUCH...WILL TREND BACK A LITTLE WITH POPS TO
REFLECT THE ADDED UNCERTAINTY BUT STILL OFFER SCATTERED SHOWERS AND
STORMS THROUGHOUT THE WEEKEND.
DAYTIME HIGHS WILL CHANGE LITTLE THROUGH THE PERIOD...REACHING THE
LOW TO MID 80S EACH DAY. OVERNIGHT LOWS WILL RESPOND TO THE FALLING
DEWPOINTS LATE IN THE WEEK...FALLING FROM THE MID TO UPPER 60S
TUESDAY NIGHT BACK INTO THE UPPER 50S TO LOW 60S THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 215 PM EDT MON JUL 22 2013
A BAND OF MODERATE TO HEAVY SHOWERS WILL LIFT NORTHEAST THROUGH THE
REST OF THE CWA OVER THE NEXT COUPLE OF HOURS. WITH THIS...THE LOWEST
VIS AND CIGS WILL OCCUR...DOWN TO LIFR FOR A TIME. OTHERWISE...MORE
SCATTERED CONVECTION WILL OCCUR THROUGH THE EVENING SO HAVE CONTINUED
A VCTS PERIOD THROUGH 04Z FOR MOST SITES. DO EXPECT SOME CLEARING
LATER TONIGHT AND THIS SHOULD BE ENOUGH TO ACTIVATE A FOGGY REGIME.
ACCORDINGLY...HAVE TAKEN THE VIS DOWN TO LIFR AT SME AND LOZ TOWARD
DAWN TUESDAY AND MVFR AT JKL FOR A TIME. MORE STORMS WILL BE POSSIBLE
ON TUESDAY...BUT DO NOT EXPECT THEM TO BECOME PREVALENT UNTIL LATER
IN THE AFTERNOON SO HAVE KEPT THEIR MENTION OUT OF THE FORECAST
THROUGH 18Z TUESDAY. BREEZY SOUTHWEST WINDS WILL SETTLE DOWN THIS
EVENING AND STAY RATHER LIGHT AND VARIABLE INTO TUESDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...ABE
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS CARIBOU ME
648 PM EDT MON JUL 22 2013
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE SOUTH TONIGHT. THE FRONT WILL
LIFT ONTO THE COAST TUESDAY WHILE A WEAK WAVE OF LOW PRESSURE
MOVES ALONG THE FRONT. A COLD FRONT WILL APPROACH TUESDAY NIGHT
THEN CROSS THE REGION WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
640 PM UPDATE: MADE SOME MODIFICATIONS TO THE PRECIP CHANCES TO
CUT THEM BACK TO SWRN ME USING THE LATEST RUC AND GEM. VISIBLE
SATL IMAGERY SHOWED SOME CLOUDS MOVING INTO WESTERN AND DOWNEAST
AREAS BUT BREAKING UP AS THEY HIT THE UPPER RIDGE HOLDING IN
PLACE. THIS RIDGE IS FCST TO BREAK DOWN AND SHIFT TO THE E OVERNIGHT
ALLOWING FOR DEEPER MOISTURE TO STREAM N INTO THE REGION FROM NYS
AND PA. TEMPERATURES WERE MODIFIED TO MATCH UP W/THE LATEST TRENDS
OF LOW TO MID 70S. TEMPERATURES WILL DROP OFF INTO THE UPPER 60S
AND LOWER 70S BY 9 PM.
PREVIOUS DISCUSSION...
HIGH PRESSURE WILL MOVE AWAY TO THE EAST TONIGHT AS CLOUDS
INCREASE AHEAD OF AN APPROACHING WARM FRONT. AS THE WARM FRONT
LIFTS NORTH INTO THE GULF OF MAINE TUESDAY MORNING A WEAK WAVE
OF LOW PRESSURE TRACKING ALONG THE FRONT WILL CARRY AN AREA OF
RAIN INTO THE DOWNEAST REGION. THE LAST FEW RUNS OF THE GFS
INDICATE THAT THE RAIN WILL LIFT NORTH TUESDAY MORNING MOVING
ACROSS CENTRAL AND EASTERN MAINE AND REACHING NORTHEAST MAINE BY
MIDDAY. THE NAM CONFINES SIGNIFICANT RAIN TO DOWNEAST AND EAST
CENTRAL AREAS. FOR NOW WILL FORECAST DEFINITE RAIN DOWNEAST AND
LIKELY OVER THE NORTH WITH JUST CHANCE IN THE FAR NORTH. THE WARM
FRONT STALLS JUST INLAND FROM THE COAST AS THE INITIAL WAVE
SLIDES NORTHEAST THROUGH NEW BRUNSWICK LATE TUESDAY. SOME SHOWERS
MAY CONTINUE...MAINLY IN DOWNEAST AREAS...AS A SMALL SECONDARY
SHORTWAVE MOVING ALONG THE FRONTAL BOUNDARY TRACKS INTO CENTRAL
NEW ENGLAND.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A DISTURBANCE WILL MOVE ALONG A FRONT ALONG THE DOWNEAST COAST
TUESDAY NIGHT...WITH A COLD FRONT APPROACHING NORTHWEST MAINE
LATE. AN AREA OF RAIN WILL MOVE ACROSS THE REGION WITH THE
DISTURBANCE TUESDAY NIGHT. THIS AREA OF RAIN WILL MOVE EAST
OVERNIGHT...WITH PRECIPITATION TAPERING TO SHOWERS LATE. SHOWER
CHANCES WILL THEN BEGIN TO INCREASE ACROSS NORTHWESTERN AREAS
LATER TUESDAY NIGHT IN ADVANCE OF THE APPROACHING COLD FRONT.
SHOWERS AND THUNDERSTORMS WILL CROSS THE REGION IN ADVANCE OF THE
COLD FRONT WEDNESDAY...THEN END IN THE WAKE OF THE COLD FRONT
THROUGH THE AFTERNOON. HIGH PRESSURE WILL BUILD EAST WEDNESDAY
NIGHT THEN CROSS THE REGION THURSDAY THROUGH THURSDAY NIGHT WITH
PARTLY CLOUDY/MOSTLY CLEAR SKIES. TEMPERATURES WILL BE AT NEAR
NORMAL...TO SLIGHTLY BELOW NORMAL...LEVELS WEDNESDAY THROUGH
THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE EXTENDED MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. A
WEAK HIGH PRESSURE RIDGE WILL BE BUILT OVER THE AREA AT THE START
OF THE PERIOD. THERE WILL BE A LOW PRESSURE SYSTEM ALONG THE
COAST OF VA...A SECOND LOW PRESSURE SYSTEM OVER LAKE SUPERIOR. FRI
EVNG THE LOW ALONG THE COAST OF VA WILL MOVE NORTH. THE GFS AND
ECMWF DIFFER ON THE SOLUTION. THE ECMWF BRINGS THE LOW NORTH ALONG
THE COAST CENTERED AROUND LONG ISLAND..WITH A WARM FRONT EXTENDING
NE INTO THE GULF OF MAINE. THE GFS MOVES THE LOW NORTH BUT KEEPS
IT WELL EAST OF THE COAST...AND MAINTAINS THE HIGH PRESSURE RIDGE
ACROSS THE AREA. THESE DIFFERENCE CONTINUE INTO SAT MRNG. THE
ECMWF MOVES THE LOW NORTH TO BAR HARBOR...EXTENDS THE WARM FRONT
EAST INTO NEW BRUNSWICK. THE GFS CONTINUES TO MAINTAIN THE HIGH
PRESSURE RIDGE. BOTH MODELS DEEPEN THE LOW OVER LAKE SUPERIOR AND
MOVE IT NORTH TO JAMES BAY. BOTH MODELS ALSO SHOW SEVERAL
SECONDARY LOWS ALONG A BOUNDARY EXTENDING THROUGH THE GREAT
LAKES...THROUGH THE CENTRAL US...TO TEXAS. BY SUN MRNG BOTH MODELS
MOVE THE RIDGE EAST OF THE AREA...AS THE FRONT PUSHES INTO VT/NH.
BY SUN EVNG THE GFS MOVES THE FRONT INTO WRN MAINE...THE ECMWF
INTO NH. MON MRNG THE GFS TO ERN ME...ECMWF WRN ME. MON EVNG THE
GFS MOVES THE FRONT THROUGH...THE ECMWF TO ERN ME. BY THE END OF
THE PERIOD THE GFS INDICATES THAT MAINE WILL BE INFLUENCED BY WRAP
AROUND PRECIP...THE ECMWF MAINTAINS THE LOW OVER MAINE.
LOADED MODEL BLEND FOR MAX/MIN TEMP...WND/SKY/POP. ADDED 15
PERCENT TO WINDS FOR GUSTS OVER LAND...20 PERCENT OVER COASTAL
WATERS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR CONDITIONS THIS EVENING ARE EXPECTED TO LOWER TO
IFR DOWNEAST LATE TONIGHT AND IFR TO MVFR ACROSS THE NORTH TUESDAY
MORNING. IFR CONDITIONS IN LOW CLOUDS ARE EXPECTED ON TUESDAY.
SHORT TERM: MVFR/IFR...WITH OCCASIONAL LIFR...CONDITIONS ARE
EXPECTED ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
CONDITIONS WILL BEGIN TO IMPROVE LATER WEDNESDAY IN THE WAKE OF
THE COLD FRONT. GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS THE
REGION WEDNESDAY NIGHT THROUGH SATURDAY.
&&
.MARINE...
NEAR TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA THROUGH
TUESDAY. HUMID AIR LIFTING NORTH WITH THE WARM FRONT WILL LIKELY
RESULT IN SOME FOG OVER THE WATERS LATE TONIGHT INTO TUESDAY.
SHORT TERM: SMALL CRAFT ADVISORY LEVEL SEAS ARE POSSIBLE WEDNESDAY
INTO WEDNESDAY NIGHT. OTHERWISE...WINDS/SEAS ARE EXPECTED TO BE
BELOW SMALL CRAFT ADVISORY LEVELS TUESDAY NIGHT THROUGH THURSDAY
NIGHT. VISIBILITIES WILL BE REDUCED IN RAIN AND FOG TUESDAY NIGHT
AND WEDNESDAY...WITH A CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BLOOMER/HEWITT
SHORT TERM...NORCROSS
LONG TERM...NORTON
AVIATION...BLOOMER/HEWITT/NORCROSS
MARINE...BLOOMER/HEWITT/NORCROSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
142 PM EDT MON JUL 22 2013
.SYNOPSIS...
ISSUED AT 407 AM EDT MON JUL 22 2013
HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH
ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE
NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS
THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS
NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS
AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF
OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO
NORTHERN MICHIGAN.
&&
.UPDATE...
ISSUED AT 1200 PM EDT MON JUL 22 2013
MID MORNING SURFACE ANALYSIS SHOWS 999MB LOW CENTER OVER NORTHWEST
ONTARIO JUST NORTH OF THE BOUNDARY WATERS...TRAILING COLD FRONT
EXTENDS BACK INTO SOUTHWEST MINNESOTA/EASTERN NEBRASKA WITH A WARM
FRONT EXTENDING SOUTHEAST ACROSS CENTRAL UPPER/NORTHWEST LOWER
MICHIGAN. MOISTURE HAS BEEN INCREASING ACROSS MICHIGAN OVER THE
LAST 24 HOURS...PRECIPITABLE WATER ON 12Z APX SOUNDING HAS DOUBLED
SINCE 12Z SUNDAY (1.07 INCHES). STRAIGHT MODIFICATION OF THE
SOUNDING MIXING TO 800MB (78/58) ONLY YIELDS AROUND 400J/KG MLCAPE
BUT DEW POINTS HAVE BEEN CLIMBING INTO THE LOWER 60S...AND
TEMPERATURES ALREADY IN THE MID/UPPER 70S. SO AN 81/63 PARCEL
PUSHES MLCAPE VALUES ABOVE 1100J/KG. ALREADY GETTING SOME CU
DEVELOPING EAST OF AN LDM-PZQ LINE...AND A FEW RADAR RETURNS
POPPING UP ALONG THE THUMB.
BASIC FORECAST IDEAS WILL REMAIN INTACT WITH CONVECTION POPPING UP
THIS AFTERNOON...WITH 1000-1500J/KG MLCAPE EXPECTED. WILL KEEP
NORTHWEST LOWER SHORELINE COUNTIES DRY WITH AN ONSHORE BREEZE/LAKE
SHADOW. DEEP LAYER SHEAR NOT STRONG TODAY...SOME DECENT VEERING OF
WINDS ALOFT BUT NOT MUCH SPEED SHEAR (0-6KM BULK SHEAR VALUES
20-30KTS). HAVE BEEN ADJUSTING THE TIMING A BIT GIVEN CURRENT
TRENDS. FORECAST HIGHS UPPER 70S-MID 80S LOOK FINE.
UPDATE ISSUED AT 638 AM EDT MON JUL 22 2013
ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN
SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN
ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY
STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF
HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM
FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE
ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON
FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD
POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE
INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD
STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE
EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT
SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END
CHANCE FOR A SEVERE STORM OR TWO.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 407 AM EDT MON JUL 22 2013
INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN
CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE
A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT.
OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING
ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME
ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN
MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER
FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN
BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF
07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS
THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX
LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH
THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST
NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A
SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND
WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE
LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR
NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW
OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN
RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY
ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE
OF LAKE MICHIGAN.
CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A
FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER
LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH
LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH
INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH
BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF
THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME
POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY
MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS
WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF
CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A
SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER
LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION
THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT
NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES
NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN.
THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY
AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS
RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY
IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL
PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM
ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE
LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW
SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z.
INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE
UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST
CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS
CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL
LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T
LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER
PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT
BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY
WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY
AREAS.
THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE
THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN
ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z.
BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A
LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD
1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE
SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST
AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING
EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL
TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY
CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE
OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND
MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY
SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF
THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S
THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE
BOUNDARY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON JUL 22 2013
THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC
TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT
WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY
EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK
WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING
STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER
RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF
THE NEXT WORK WEEK.
TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT
UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY
MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN
THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD.
TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY
COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN
THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH
THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL
SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL
WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN
OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO
ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES
INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW
WISCONSIN.
THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE
AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE.
TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS
AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT.
REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL
RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS
THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT
IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW
OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME
TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET
EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED
ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A
RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL
ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED
LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING
RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES
FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE
APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES
IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND
LOWER 70S FOR THE UPCOMING WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 140 PM EDT MON JUL 22 2013
COUPLE PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE AHEAD OF A COLD
FRONT TO CROSS NORTHERN MICHIGAN OVERNIGHT. WINDS SHIFT TO THE
NORTHWEST BEHIND THE FRONT AND PERHAPS A PERIOD OF HIGH END IFR
CEILINGS EARLY TUESDAY MORNING.
&&
.MARINE...
ISSUED AT 407 AM EDT MON JUL 22 2013
LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST
AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING
THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT
ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND
TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS.
THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH
THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS
THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF
SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD
PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE
WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING
HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED.
HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK...
GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH
THURSDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JPB
SYNOPSIS...SD
SHORT TERM...DL
LONG TERM...SD
MARINE...DL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
134 PM EDT MON JUL 22 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EDT MON JUL 22 2013
A WARM FRONT WILL BRING A FEW SHOWERS AND THUNDERSTORMS LATER TODAY
AND THEN A COLD FRONT WILL BRING MORE SCATTERED SHOWERS AND STORMS
TONIGHT INTO TUESDAY. FAIR AND COOLER WEATHER WILL ARRIVE BY LATE
TUESDAY AND LAST THROUGH THURSDAY. TEMPERATURES WILL AVERAGE NEAR
NORMAL LATE IN THE WEEK THROUGH NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 1110 AM EDT MON JUL 22 2013
DROPPED MAXIMUM TEMPERATURES TODAY SLIGHTLY MAINLY SOUTH OF I-96
TO ACCOUNT FOR THE COOLING EFFECTS OF EXTENSIVE PRECIPITATION
OVERNIGHT AND RESIDUAL CLOUD COVER. ALSO RAISED PRECIPITATION
CHANCES EAST OF US-131 BASED ON HRRR MODEL GUIDANCE AND TO BETTER
AGREE WITH SURROUNDING OFFICES. MAIN FORECAST CONCERN THIS
AFTERNOON WILL BE PRECIPITATION CHANCES OVERNIGHT WITH THE
APPROACHING COLD FRONT.
UPDATE ISSUED AT 537 AM EDT MON JUL 22 2013
A COUPLE OF SHOWERS DEVELOPED IN THE PAST HR...ESPECIALLY NEAR
LWA. WENT AND ADDED A RISK FOR A FEW EARLY MORNING SHOWERS
PRIMARILY SOUTH OF A BIV TO LAN LINE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON)
ISSUED AT 330 AM EDT MON JUL 22 2013
AFTER SOME LINGERING EARLY MORNING SHOWERS OVER OUR SE FCST AREA DRY
WX IS ANTICIPATED FOR THE REST OF THE MORNING IN THE WAKE OF THE
DEPARTING MCV THAT BROUGHT THE ROUND OF RAIN AND STORMS YESTERDAY
EVENING AND OVERNIGHT.
SOME WAA SHOWERS AND A FEW STORMS WILL DEVELOP THIS AFTERNOON. A
FAIR AMOUNT OF SUN AND SSW WINDS WILL HELP
TO BOOST MAX TEMPS INTO THE LOWER TO MIDDLE 80S ACROSS MOST OF OUR
AREA TODAY.
THE COLD FRONT WILL MOVE IN FROM THE NW TONIGHT AND BRING SCATTERED
SHOWERS AND STORMS WHICH WILL LAST THROUGH ABOUT MIDDAY TUESDAY
BEFORE THE FRONT CLEARS OUR AREA. A COOLER AND DRIER AIR MASS WILL
ADVECT IN BEHIND THAT FRONT AND MAX TEMPS WEDNESDAY WILL ONLY REACH
THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON JUL 22 2013
PATTERN IS LOOKING COOLER WITH TIME ESPECIALLY THIS WEEKEND. MODELS
IN DECENT AGREEMENT IN SHOWING A COLD FRONT PUSHING THROUGH FRI
NIGHT INTO SAT WITH A WAVE OF LOW PRESSURE FORMING ON IT OVER
SOUTHERN LOWER MI. THIS SHOULD LEAD TO SHOWERS AND WITH INSTABILITY
AROUND THUNDERSTORMS. IF THE NEW HIGH RES EURO IS CORRECT SAT COULD
BE A RATHER WET DAY FOR THE AREA. NORTHERLY FLOW SETS UP BEHIND
THE WAVE LEADING TO STRONG COLD AIR ADVECTION. 925 MB TEMPS FALL
TO UNDER 10 DEG C 12Z SUN. IF THIS HAPPENS AND THE UPPER LOW
DEVELOPS NORTH OF SUPERIOR AS SHOWN BY THE HIGH RES EURO ON
SUN...LAKE ENHANCED MOISTURE MAY IMPACT THE FORECAST. I LOWERED
TEMPERATURES OVER GUIDANCE FOR SAT NIGHT THROUGH SUN BASED ON THIS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 134 PM EDT MON JUL 22 2013
THERE ARE A COUPLE OF PERIODS OF NOTE IN THE 18Z FCST PACKAGE.
FIRST OF ALL...WE ARE SEEING FAIRLY GOOD CUMULUS DEVELOPMENT EARLY
THIS AFTERNOON WITH PLENTY OF INSTABILITY PRESENT. THIS HAS
INITIALLY DEVELOPED AS MVFR...BUT SHOULD LIFT TO VFR FAIRLY QUICK. SOME
CONVERGENCE PRESENT THIS AFTERNOON COULD HELP POP A FEW SHOWERS
AND/OR STORMS THROUGH EARLY EVENING. THE CHCS OF THESE HITTING A TERMINAL
ARE NOT VERY HIGH...SO WE HAVE USED A VCSH TO COVER THIS FOR NOW.
SOME BRIEFLY LOWER CONDITIONS TO MVFR WILL BE POSSIBLE UNDER ANY
SHOWER/STORM.
ANOTHER THREAT OF SHOWERS AND/OR STORMS WILL BE POSSIBLE AFTER
ABOUT 06Z AT KMKG AND THEN SPREAD TO THE SE OVERNIGHT AHEAD OF A
COLD FRONT. WE ARE NOT ENTIRELY SURE EVERYONE WILL SEE RAIN FROM
THIS AS PCPN LOOKS TO BE DIMINISHING WITH THE FRONT DUE TO THE
LOSS OF DIURNAL INSTABILITY. THIS WARRANTS A VCSH ALSO...AND WE
CAN FINE TUNE THIS AS TRENDS REVEAL THEMSELVES BETTER. WINDS WILL
SHIFT TO THE NW AFTER THE FRONT PASSES TUE MORNING. A MVFR CLOUD
DECK SHOULD MOVE IN BEHIND THE FRONT FOR A FEW HOURS TUE MORNING
BEFORE IT LIFTS TUE AFTERNOON.
&&
.MARINE...
ISSUED AT 1110 AM EDT MON JUL 22 2013
LATEST OMR SHOWS WAVE HEIGHTS GENERALLY BELOW 2 FEET...ALTHOUGH 3
FEET WAS REPORTED AT GRAND HAVEN. AS NOTED IN THE PREVIOUS
DISCUSSION...WINDS AND WAVES WILL INCREASE TODAY. ALTHOUGH A SMALL
CRAFT ADVISORY IS NOT ANTICIPATED...WE WILL HAVE TO WATCH THE
BEACH HAZARD POTENTIAL /PRIMARILY INCREASING LONG SHORE CURRENTS/
AS IT EVOLVES THIS AFTERNOON AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT MON JUL 22 2013
NO HYDRO ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...TJT
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MJS
AVIATION...NJJ
HYDROLOGY...LAURENS
MARINE...TJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
101 PM CDT MON JUL 22 2013
.UPDATE...
FOR 18Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT MON JUL 22 2013
EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE
TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE
SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING
FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN
OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE
ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE
TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT
COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS
SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE
ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT
BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE
22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING
SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE
SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL
WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING
THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE
INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR
STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH
CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG
THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY
/MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK
SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW
FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35.
CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE
FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT.
HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST
CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE
AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH
GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS
TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND
LOWER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 AM CDT MON JUL 22 2013
MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY
PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS
IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF
CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A
BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT.
THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A
SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN
STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS
THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT
CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL
BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES
RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST
MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS
WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH
SATURDAY.
AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF
TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO
THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND
MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE
GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE
ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO
FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS
KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE
SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE
DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF
THE BUNCH.
FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN
IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ
FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN
A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK
TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES
IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED
OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS
MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR
ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE
POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY
POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE
BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF
MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA
OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE.
ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF
WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND
ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE
MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH.
IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS
WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE
22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD
LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK
TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED
LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE
ABLE MAKE A RUN AT THAT RECORD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM CDT MON JUL 22 2013
THE COLD FRONT NOW EXTENDS FROM ROUGHLY SIOUX FALLS...TO THE
WESTERN TWIN CITIES METRO...TO JUST SOUTHEAST OF DULUTH. SO
FAR...THE FRONT IS JUST MANAGING TOWERING CUMULUS CLOUDS WITH
CLOUDS BASES NEAR 3000 FT IN MOST LOCATIONS. A BRIEF PERIOD /1-3
HOURS/ OF MVFR CEILINGS IS POSSIBLE WITH THE COLD FRONT. WE ARE
ALSO SEEING SOME SHOWERS DEVELOP IN NORTHWEST WI...BUT MINNESOTA
AND WESTERN CENTRAL WI REMAIN STORM FREE AT THIS POINT. KEAU HAS
THE BEST CHANCE FOR THUNDER. WE NOW THINK STORMS WILL MISS ALL THE
OTHER TAF SITES BESIDES KEAU.
KMSP...
THE COLD FRONT /WITH A WIND SHIFT TO THE W-NW/ PASSED BY THE OFFICE
HERE IN CHANHASSEN AT ABOUT 1245 PM...SO IT WILL BE AT THE AIRPORT
WITHIN 30 MINUTES OR SO. GIVEN THAT THE STORM ACTIVITY HAS BEEN
SUPPRESSED UP UNTIL NOW...WE THINK THERE IS NOT ENOUGH TIME TO
DEVELOP STORMS BEFORE THE COLD FRONT PASSES THROUGH. STORM CHANCES
LOOK BETTER 50-75 MILES EAST OF THE AIRPORT. COULD HAVE LINGERING
STRATO CU WITH A SCT-BKN 2500-3500 FT DECK LATE THIS AFTERNOON OR
EARLY EVENING...BUT THE MORE WIDESPREAD CLOUDS SHOULD REMAIN IN
NORTHERN/WESTERN MN. NO AVIATION WEATHER CONCERNS TOMORROW.
/OUTLOOK FOR KMSP/
TUE/TUE NIGHT...VFR. WINDS N 5 TO 10 KT.
WED...VFR. CHANCE OF SHRA/TSRA LATE NIGHT. WINDS S 5 KT.
THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS WSW 5 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...MPG
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1239 PM CDT MON JUL 22 2013
.UPDATE...
ISSUED AT 911 AM CDT MON JUL 22 2013
FIRST FORECAST UPDATE OF THE DAY HAS BEEN SENT. IN SHORT...ANOTHER
TRICKY DAY/EVENING OF THUNDERSTORM CHANCES AWAITS THE LOCAL AREA.
ESSENTIALLY...THE ONLY NOTABLE CHANGE FROM PREVIOUS FORECAST SO
FAR WAS TO TRIM CENTRAL/NORTHEAST PORTIONS OF THE CWA FROM ANY
THUNDERSTORM MENTION THIS MORNING...WHILE LEAVING MORNING CHANCES
INTACT IN KS ZONES...AND MAINLY WEST OF A GOTHENBURG-ALMA LINE IN
NEBRASKA TO ACCOUNT FOR THE FAIRLY PERSISTENT NARROW NORTHWEST-
SOUTHEAST AXIS OF CONVECTION PRIMARILY AFFECTING FURNAS COUNTY AT
THIS TIME. OTHER THAN MAYBE SOME SMALL HAIL...NOT EXPECTING A
MORNING SEVERE THREAT. FOR THIS AFTERNOON...ITS HARD TO ARGUE WITH
THE SPC SLIGHT RISK FOR ROUGHLY THE SOUTHEAST 2/3 OF THE
CWA...ALTHOUGH ITS TOUGH TO SAY WHETHER WE MIGHT ONLY GET 1 OR 2
ISOLATED STRONG-SEVERE STORMS...OR POTENTIALLY MORE SCATTERED
COVERAGE. EITHER WAY...THE PRIMARY FORCING MECHANISM ALOFT LOOKS
TO BE A FAIRLY SUBTLE SHORTWAVE TROUGH DRIFTING EAST-SOUTHEAST OUT
OF WYOMING...WHILE AT THE SURFACE A FAIRLY WEAK COLD FRONT WILL
SINK SOUTHWARD INTO PARTS OF THE CWA AS THE DAY WEARS
ON...PROVIDING AT LEAST LIMITED LOW-LEVEL CONVERGENCE. THE LATEST
RAP FORECAST VALID FOR 21Z/4PM PAINTS 1000-2500 J/KG OF 0-1KM
MLCAPE ACROSS MOST OF THE CWA...HIGHEST IN THE SOUTH...IN THE
PRESENCE OF DECENT 0-6KM DEEP LAYER SHEAR OF 35-40KT...SO
CERTAINLY A THREAT FOR SOME SOUTHEAST-MOVING STRONG TO SEVERE
STORMS AND POTENTIALLY SUPERCELLS EXISTS...ALTHOUGH WORKING AGAINST
STORM FORMATION APPEARS TO BE AT LEAST A WEAK CAP EVIDENT ON
FORECAST SOUNDINGS AROUND 700-650 MILLIBARS...SO ITS ALSO NOT OUT
OF THE QUESTION THAT OUR LOCAL AREA COULD LARGELY STEER CLEAR OF
AN AFTERNOON/EVENING STORM THREAT...WITH BETTER CHANCES
POTENTIALLY FOCUSING JUST TO OUR SOUTH/EAST. EVEN THOUGH THE
GREATEST SEVERE THREAT WOULD THEORETICALLY FOCUS ACROSS SOUTHERN
PORTIONS OF OUR AREA...HAVE PUT AT LEAST A SLIGHT CHANCE OF STORMS
EVEN IN FAR NORTHERN COUNTIES FOR AT LEAST A FEW HOURS THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT MON JUL 22 2013
THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST
THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN
COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH
SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL
GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO
NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND
SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER
BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF
THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE
UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE
EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF
THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR
THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR
FLOW.
THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF
DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS
WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND
MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR
SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS
TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE
WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED
LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS
COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING
CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES
THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE
RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH
WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS
ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND
06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD
NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY
CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE
DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST
OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED
CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD
PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF
AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE
MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE
AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY
THEN.
THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS
AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST
AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR
VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY
WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE
TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE
LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST
STORMS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 349 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS WILL BE
CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND
TEMPERATURES.
MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE
PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN
DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A
LITTLE DIFFERENT WITH EACH MODEL.
THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY
NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS
SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS
DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE
EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE
AREA. TEMPERATURES WILL BE COOLER THAN TODAY.
A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND
INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY.
TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY
WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF
THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE
IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY
NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME
LINGERING THUNDERSTORMS.
FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL
WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY
MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE
OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER
SIDE DURING THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1239 PM CDT MON JUL 22 2013
AS A RESULT OF THIS PESKY NORTHWESTERLY FLOW ALOFT...THE CHALLENGE
HERE DURING THIS TAF PERIOD IS DETERMINING PRECIPITATION CHANCES
OVER THE TERMINAL. THUNDERSTORMS CANNOT BE COMPLETELY RULED OUT
TODAY/TONIGHT...HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH AT THE
MOMENT TO PUT A MENTION IN THE TAF. WILL AMEND IF CONDITIONS
CHANGE. WITH THAT BEING SAID...VFR CONDITIONS SHOULD PREVAIL AT
THE TERMINAL SITE. THE WIND WILL REMAIN FROM THE NORTH FOR THE
FIRST SEVERAL HOURS AS A COLD FRONT SLIDES THROUGH THE
REGION...BUT THE WIND SHOULD SHIFT AND BECOME MORE WESTERLY AS WE
PROGRESS THROUGH OVERNIGHT PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1112 AM CDT MON JUL 22 2013
.UPDATE...
UPDATED FOR CONVECTIVE TRENDS THROUGH THE DAY
&&
.DISCUSSION...
12Z UPPER AIR ANALYSIS INDICATED A POTENT UPPER LEVEL SYSTEM
MOVING THROUGH SRN CANADA ASSOCIATED WITH AN 80 KT H3 JET AND 50
M H5 HEIGHT FALLS. THIS WAS ALLOWING FOR A COLD FRONT TO PUSH SEWD
INTO THE FA THIS MORNING...AND EXTENDED FROM NEAR SUX TO ODX AT
15Z. THERE WAS ALSO A 60 KT JET SEGMENT ASSOCIATED WITH A SUBTLE
SHRTWV TROUGH OVER ERN WY. MID-LEVEL LAPSE RATES HAD IMPROVED OVER
THE LAST 24 HOURS ACROSS THE CENTRAL PLAINS WITH H7 TO H5 DELTA-T
VALUES OF +20 C FROM OAX UPSTREAM TO RAP/LBF AND INTO THE
ROCKIES. A NWRLY H85 WND AHEAD OF THE COLD FRONT HAD PUSHED THE
MOISTURE AXIS TO THE S AND E OF OAX...BUT +15 C H85 DEW POINTS
WERE NOTED ALONG AND JUST BEHIND THE FRONT /INCLUDING A 16 C H85
DEW POINT AT RAP/. THE COMBINATION OF THE BETTER MID LEVEL LAPSE
RATES AND MOISTURE ALONG THE FRONT WILL LEAD TO A STRONGLY UNSTABLE
ATMOSPHERE ACROSS THE FA THIS AFTERNOON WITH MLCAPE APPROACHING
3500 J/KG...WHICH APPEARS REASONABLE GIVEN THE MODIFIED KOAX 12Z
SOUNDING.
KOAX 88-D CONTS TO INDC SOME SCT TSRA JUST BEHIND THE SFC
BOUNDARY MOVING INTO NE NEB LATE THIS MORNING AND WE FEEL THIS
ACTIVITY WILL CONT TO DRIFT TO THE SE THRU THE AFTN. THIS ACTIVITY
IS CURRENT ELEVATED ABOVE THE NOCTURNAL INVERSION WITH A LIKELY
EFFECTIVE INFLOW LAYER JUST ABOVE 850 MB. THIS ACTIVITY WAS
HANDLED WELL BY GOING FORECAST REQUIRING LITTLE CHANGE. THE MAIN
NEGATIVE THAT WILL LIKELY KEEP CONVECTIVE COVERAGE FAIRLY ISOLATED
TODAY IS THE LACK OF MORE ORGANIZED LARGE-SCALE ASCENT AND RATHER
WEAK SFC CONVERGENCE ALONG THE FRONT. THE WY SHRTWV TROUGH WILL
LIKELY AFFECT WRN NEB INTO KS AND THE CANADIAN SHRTWV SHOULD STAY
WELL TO THE NORTH. THUS THE BEST COVERAGE IS LIKELY TO BE IN WRN
IA AND WE WILL CENTER THE HIGHEST POPS THERE WITH MORE ISOLATED
ACTIVITY IN E-CNTRL AND SE NEB.
THERE IS SOME THREAT OF AN ISO SVR STORM TODAY...BUT WEAK
EFFECTIVE SHEAR /GENERALLY LESS THAN 20 KT/ SHOULD KEEP ANY THREAT
ISOLATED AND SHORT-LIVED. THE BETTER DEEP LAYER SHEAR /> 30 KT/ WILL
ACTUALLY BE OVER THE SRN CWA IF CONVECTION CAN MAKE IT INTO THAT
AREA LATE THIS AFTN AND EVENING. ALL THE ACTIVITY WILL LIKELY PUSH
OUT OF THE AREA BY MID EVENING...BUT ANOTHER SHRTWV TROUGH /SEEN
IN THE 12Z UPPER AIR ANALYSIS OVER WA/ MAY LEAD TO CONVECTION
ROLLING OFF THE HIGH PLAINS OVERNIGHT AND THIS WILL BE DISCUSSED
MORE IN THE AFTERNOON AFD.
BOUSTEAD
&&
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD EXCEPT IN POSSIBLE
TSRA. THIS APPEARS MOST LIKELY AT OMA FROM AROUND 19-22Z AND LNK
AROUND 21-24Z WITH MVFR CIGS/VISBY POSSIBLE. OTHERWISE A SFC CDFNT
WILL MOV THROUGH OFK NEAR 18Z AND OMA/LNK BY AROUND 21Z WITH WINDS
SHIFTING FROM SW TO NW AT ALL LOCATIONS. MOST CLEAR CONDITIONS ARE
EXPECTED OVERNIGHT WITH LIGHT WINDS.
&&
PREV DISCUSSION... /ISSUED 304 AM CDT MON JUL 22 2013/
DISCUSSION...
PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE
CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z
WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA
INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL
NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA
BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA
THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY
STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN
THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND
OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY
EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE
WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO
THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH
SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35
KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND
THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING.
SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION
REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST
THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH
PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE
SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY
WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS
THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST
THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S
ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL
SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER
INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD
LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH
SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS
ARE EXPECTED TUESDAY AS WELL.
THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY
THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING
THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN
PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A
SMALL PRECIP CHANCE SUNDAY INTO MONDAY.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
637 PM EDT MON JUL 22 2013
.SYNOPSIS...
A TROF OF LOW PRESSURE WILL LINGER INLAND THROUGH TUESDAY. A COLD
FRONT WILL SLOWLY PUSH THROUGH WEDNESDAY AND WEDNESDAY NIGHT...BECOMING
STATIONARY NEAR THE COAST THURSDAY AND FRIDAY. THE FRONT WILL
DISSIPATE ON SATURDAY WITH ANOTHER COLD FRONT APPROACHING FROM THE
NORTHWEST MONDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 630 PM MONDAY...A DEEP MID-LEVEL TROUGH LIES ACROSS THE
TENNESSEE VALLEY WITH HIGH PRESSURE CONTINUE OVER THE CENTRAL
ATLANTIC. THIS CONTINUES TO CIRCULATE VERY MOIST AIR INTO EASTERN
NORTH CAROLINA AS LATEST MESOANALYSIS GRAPHICS INDICATES
PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES AREA-WIDE. THE 3
KM HRRR HAS ONCE AGAIN TODAY HAD THE BEST DEPICTION OF THE
LOCATION OF PRECIPITATION AND GENERALLY SHOWS ACTIVITY LINGERING
ACROSS THE CENTRAL AND WESTERN COASTAL PLAINS FOR A FEW MORE HOURS
BEFORE GRADUALLY DISSIPATING LATER TONIGHT AND HAVE SHOWN CHANCE
POPS INLAND TO SLIGHT CHANCE COAST THROUGH THE BALANCE OF THE
EVENING. MADE NO CHANGES TO CURRENT MINIMUM TEMPERATURE FORECAST
WITH LOWS PREDICTED IN THE 72 TO 77 DEGREE RANGE CWA WIDE.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH 6 PM TUESDAY/...
AS OF 230 PM MON...TROUGHING INLAND AND HIGH PRESSURE OFF THE SE
COAST WILL CONTINUE TUE. SCT CONVECTION EXPECTED AGAIN...MAINLY
DIURNAL DRIVEN BY SEABREEZE AND SHORTWAVE APPROACHING FROM THE
WEST. FORECAST SOUNDINGS A BIT DRIER THAN PAST SEVERAL DAYS. AN
ISOLATED STRONG STORM WILL BE POSSIBLE AS SHEAR INCREASES...WITH
GUSTY WINDS...HEAVY RAIN...AND FREQ LIGHTNING. LOW LEVEL THICKNESS
VALUES AND TEMPS ALOFT SUPPORT HIGHS IN THE UPPER 80S TO LOWER
90S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 215 PM MON...SIGNIF MDL DIFFERENCES CONT AND LEANED A BIT
MORE TWRD ECMWF AND AWAY FROM GFS. UPR TRF WILL DEVELOP TO THE W
MID WEEK THEN SWING THRU FRI/FRI NIGHT. ANOTHER PIECE OF ENERGY
WILL MOVE THRU THE TRF OVER THE WEEKEND AND SWING N OF THE AREA
EARLY NEXT WEEK. WEAK FRONT WILL MOVE INTO THE AREA LATER WED AND
DRIFT TO THE CST THU BEFORE STALLING NEAR THE CST FRI INTO SAT.
THE INIT FRONT WILL DISSIPATE SUN THEN ANOTHER COLD FRONT ASSOC
WITH THE SECOND UPR TRF WILL APPROACH FROM THE W MON. APPEARS MOST
OF TUE NIGHT AND WED WILL BE RAIN FREE AS ATMS DRIES A BIT IN WAKE OF
SRT WAVE....DID KEEP SLIGHT POPS IN. POPS INCREASE WED NIGHT AND
THU WITH FRONT IN THE AREA AND APPROACHING UPR TRF...FOR NOW KEPT
POPS IN CHC RANGE...LATER SHIFTS CAN BUMP UP IF MDLS BECOME MORE
SIMILAR. SCT CONVECTION WILL CONT FRI WITH THE FRONT STALLED IN THE
VCNTY AND UPR TRF CROSSING. LOOKS A BIT DRIER OVER THE WEEKEND AS
INIT TRF SHIFTS OFF THE CST. COULD SEE A BIT BETTER CVRG LATER SUN
AND MON AS SECOND TRF APPROACH AND PASSES TO THE N.
TEMPS WILL REMAIN NEAR NORMAL WED WITH LOWER 90S INLAND AND
MID/UPR 80S CST. WITH FRONT IN AREA AND FALLING HGTS EXPECT
SLIGHTLY COOLER TEMPS REST OF THE PERIOD WITH HIGHS IN THE 80S.
DESPITE POSS OF SOME N/NE WINDS LOOKS LIKE DEWPTS WILL MAINLY STAY
AOA 70 KEEPING LOW IN THE 70S AREA-WIDE.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY/...
AS OF 230 PM MON...SCT SHOWERS AND THUNDERSTORMS CONTINUE ACROSS
THE CENTRAL CWA. KEWN AND KISO HAVE ALREADY HAD SHOWERS AND KPGV
COULD ALSO CATCH A SHOWER IN THE NEXT HOUR OR TWO. EXPECT
ACTIVITY TO WANE WITH LOSS OF HEATING. MAIN QUESTION WILL BE IF
STRATUS FORMS LATE TONIGHT AND ITS EXTENT. SINCE RAINFALL HAS
ALREADY OCCURRED AT KEWN AND KISO AND SHOWERS WILL BE NEAR KPGV
FOR THE NEXT COUPLE OF HOURS...WILL HIT THE STRATUS A BIT HARDER AT
THESE SPOTS...WITH CEILINGS NOT QUITE AS LOW AT KOAJ. DIURNAL
CONVECTION LIKELY AGAIN TUE AFTERNOON/EVENING. SWLY WINDS WILL
CONTINUE WITH GUSTS 15-20KT TUE AFTERNOON.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM MON...WL LIKELY HAVE BOUTS OF LATE NIGHT/EARLY MORN
ST/SCU WITH CIGS IN THE MVFR TO IFR RANGE AT TIMES...POSS SOME
PATCHY FOG AS WELL. DURING THE DAY/EVENING EXPECT MAINLY
VFR...HOWEVER SCT CONVECTION WILL LEAD TO BRIEF PDS OF REDUCED
FLIGHT CATEGORIES THRU THE PERIOD.
&&
.MARINE...
SHORT TERM /THROUGH TUESDAY/...
AS OF 635 PM MON...MODERATE SOUTHWEST WINDS OF 10 TO 20 KNOTS
CONTINUE OVER THE COASTAL WATERS AND SOUNDS WITH SEAS GENERALLY 2
TO 4 FEET UP NORTH AND 3 TO 5 FEET SOUTH. ONLY MINOR TWEAKS MADE
TO CURRENT MARINE FORECAST. TIGHTENED GRADIENT WILL CONTINUE TUE
WITH WINDS 10-20KT AND GUSTS TO 25KT SOUTH OF OREGON INLET...WITH
SEAS BUILDING TO 6FT ON THE OUTER WATERS. ISSUED SCA FOR WATERS
SOUTH OF OREGON INLET BEGINNING TUE INTO TUE NIGHT.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM MON...GUSTY SOUTH TO SOUTHWEST WED TUE EVENING WILL
DIMINISH INTO WED AS WEAK FRONT DRIFTS INTO THE REGION. SCA WILL
CONT MOST CSTL WTRS TUE EVENING THEN SEAS SHLD DROP BELOW 6 FT ALL
WTRS BY LATER TUE NIGHT. WIND DIR TOUGH THRU REST OF PD WITH
FRONTAL POSITION KEY...LEANED TWRD ECMWF/SREF WITH MAINLY LIGHT
ONSHORE FLOW NRN TIER AND LIGHT/VRBL SRN TIER THRU FRI. AS FRONT
DISSIPATES SAT WINDS WILL BECOME MORE SRLY. WITH FRONT NEAR CST
GRDNT SHLD BE LOOSE WITH LIGHT WINDS WED INTO SAT. SEAS WILL DROP
TO 2 TO 4 FEET LATER WED AND STAY IN THE 2 TO 3 FOOT RANGE THU
INTO SAT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM TUESDAY TO 7 AM EDT WEDNESDAY
FOR AMZ152-154.
SMALL CRAFT ADVISORY FROM 11 AM TUESDAY TO 2 AM EDT WEDNESDAY
FOR AMZ156-158.
&&
$$
SYNOPSIS...CQD
NEAR TERM...CTC
SHORT TERM...CQD
LONG TERM...RF
AVIATION...CTC/RF/CQD
MARINE...CTC/RF/CQD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
317 PM EDT MON JUL 22 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S.
THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER
CENTRAL NORTH CAROLINA THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 250 PM MONDAY...
THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS
THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT...
AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH
ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS.
THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG
AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL
LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS
OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS
SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF
2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE
WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG
THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH
CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED
IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST
CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER
TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH
OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH
THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE
COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP
TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS
ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW
LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD
MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE
WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z...
AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES
TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN
THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED
(AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING...
WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO
CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND
A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO
SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK
DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH
DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK
ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE
THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW
DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE...
69-73.
FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE...
FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING
ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF
THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL
AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE
AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL
DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY
AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY
AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING
VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED
ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP
PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED
WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL
MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER.
EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS
THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY
NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG
OVERNIGHT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM MONDAY...
A PAIR OF SHORTWAVE TROUGHS ALOFT...BOTH EMBEDDED WITHIN A SHEAR
AXIS STRETCHING FROM SOUTH-CENTRAL CANADA TO THE RELATIVELY
DATA-SPARSE EASTERN PACIFIC...WILL CROSS THE MIDDLE ATLANTIC AND
CAROLINAS THIS PERIOD - SEPARATED BY ABOUT 24 HOURS AND BOTH WITH
FAVORABLE DIURNAL TIMING FOR ENHANCED THUNDERSTORM COVERAGE EACH
AFTERNOON-EVENING. MEANWHILE AT THE SURFACE...A COLD FRONT
STRETCHING FROM THE UPPER MIDWEST TO THE CENTRAL PLAINS THIS
AFTERNOON WILL CREST THE APPALACHIANS AND MERGE WITH A LEE TROUGH BY
LATE WED...THEN DRIFT SLOWLY SOUTHEASTWARD INTO EASTERN NC BY THU.
WED AND WED NIGHT: SCATTERED THUNDERSTORMS ARE ACCORDINGLY EXPECTED
TO MAXIMIZE ALONG AND EAST OF THE MERGED SURFACE FRONT/TROUGH...WITH
LESSER COVERAGE OVER THE WESTERN PIEDMONT WHERE LOW LEVEL WNW FLOW
AND LOWER-MIDDLE 60S SURFACE DEWPOINTS ARE FORECAST TO PREVAIL.
PROJECTED 15-25 KTS OF DEEP LAYER SHEAR FAVORS MULTI-CELL CLUSTERS
CAPABLE OF KNOCKING DOWN A FEW TREES...AND PRODUCING LOCALLY HEAVY
RAIN. SHOWERS AND STORMS ARE APT TO LINGER INTO THE FIRST HALF OF
THE NIGHT IN THE COASTAL PLAIN...INVOF THE SURFACE BOUNDARY AND
PROBABLE OUTFLOW... BEFORE THE PARENT SHORTWAVE TROUGH AND
ASSOCIATED LARGER SCALE FORCING FOR ASCENT LIFT NORTHEAST OF OUR
REGION..AND NOCTURNAL COOLING/PRIOR CONVECTIVE OVERTURNING
STABILIZES THE ENVIRONMENT. WARM WITH HIGHS 89 TO 94...AND LOWS IN
THE UPPER 60S TO LOWER 70S.
THU AND THU NIGHT: NWP GUIDANCE HAS TRENDED MORE AMPLIFIED WITH THE
SECOND SHORTWAVE TROUGH FOR THU. SO WHILE THE BEST LOW LEVEL
CONVERGENCE AND MOISTURE WILL EXIST OVER SOUTHEASTERN NC...LOW LEVEL
MOISTURE ON THE COOL SIDE OF THE FRONT - IN STILL RELATIVELY-MOIST
NORTHEAST FLOW WITH DEWPOINTS IN THE UPPER 60S - WILL LIKELY PROVE
SUPPORTIVE OF SCATTERED TO PERHAPS NUMEROUS STORMS FROM NEAR KMEB TO
KGSB...WITH MORE WIDELY SCATTERED DEVELOPMENT TO THE NORTHWEST.
COOLER IN THE AFOREMENTIONED POST-FRONTAL NE FLOW...WITH HIGHS
RANGING FROM THE LOWER 80S NW PIEDMONT TO UPPER 80S SANDHILLS AND
SOUTHERN COASTAL PLAIN. LOWS AGAIN GENERALLY INT HE UPPER 60S TO
LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 315 PM MONDAY...
IT STILL APPEARS THAT THE BEGINNING OF THE MEDIUM RANGE (FRI-SAT)
WILL FEATURE SHORTWAVE RIDGING AND THE LOWEST PROBABILITY OF
PRECIPITATION DURING THE PERIOD...WITH RELATIVE HIGHEST
PROBABILITIES (30 PERCENT) OVER THE SOUTHERN TIER...WHERE BOUNDARY
LAYER MOISTURE WILL BE HIGHEST INVOF THE OLD...DIFFUSING SURFACE
FRONT. HIGHS WITHIN A FEW DEGREES OF 85..AND LOWS IN THE UPPER 60S
TO LOWER 70S.
THE SECOND HALF OF THE MEDIUM RANGE (SUN-MON) WILL FEATURE RENEWED
TROUGH AMPLIFICATION ALOFT...AND THE ARRIVAL OF AN ACCOMPANYING
SURFACE FRONTAL ZONE INTO THE EASTERN US. MOIST AND PERTURBED
SOUTHWEST FLOW ALOFT...IN A REGION OF PERSISTENT UPPER DIVERGENCE IN
THE ENTRANCE REGION OF AN ACCOMPANYING UPPER JET AND WITH LOW
LEVEL CONVERGENCE ALONG THE SLOWLY-PASSING SURFACE FRONT...FAVOR A
GOOD TO LIKELY CHANCE OF SHOWERS AND STORMS MAXIMIZED WITH DIURNAL
HEATING. NEARLY PERSISTENCE TEMPERATURES WITHIN A FEW DEGREES OF
85...AND UPPER 60S TO LOWER 70S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1230 PM MONDAY...
MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY
BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN
SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX
OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE...
SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING
FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE
EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT
THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES
MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION
DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED
02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED
TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE
CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN
LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A
BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT.
LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH
WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR
FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/
STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY
AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE
ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...HARTFIELD
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
304PM EDT MON JUL 22 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S.
THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER
CENTRAL NORTH CAROLINA THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 250 PM MONDAY...
THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS
THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT...
AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH
ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS.
THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG
AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL
LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS
OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS
SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF
2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE
WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG
THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH
CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED
IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST
CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER
TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH
OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH
THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE
COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP
TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS
ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW
LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD
MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE
WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z...
AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES
TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN
THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED
(AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING...
WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO
CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND
A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO
SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK
DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH
DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK
ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE
THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW
DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE...
69-73.
FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE...
FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING
ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF
THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL
AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE
AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL
DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY
AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY
AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING
VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED
ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP
PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED
WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL
MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER.
EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS
THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY
NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG
OVERNIGHT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM MONDAY...
A PAIR OF SHORTWAVE TROUGHS ALOFT...BOTH EMBEDDED WITHIN A SHEAR
AXIS STRETCHING FROM SOUTH-CENTRAL CANADA TO THE RELATIVELY
DATA-SPARSE EASTERN PACIFIC...WILL CROSS THE MIDDLE ATLANTIC AND
CAROLINAS THIS PERIOD - SEPARATED BY ABOUT 24 HOURS AND BOTH WITH
FAVORABLE DIURNAL TIMING FOR ENHANCED THUNDERSTORM COVERAGE EACH
AFTERNOON-EVENING. MEANWHILE AT THE SURFACE...A COLD FRONT
STRETCHING FROM THE UPPER MIDWEST TO THE CENTRAL PLAINS THIS
AFTERNOON WILL CREST THE APPALACHIANS AND MERGE WITH A LEE TROUGH BY
LATE WED...THEN DRIFT SLOWLY SOUTHEASTWARD INTO EASTERN NC BY THU.
WED AND WED NIGHT: SCATTERED THUNDERSTORMS ARE ACCORDINGLY EXPECTED
TO MAXIMIZE ALONG AND EAST OF THE MERGED SURFACE FRONT/TROUGH...WITH
LESSER COVERAGE OVER THE WESTERN PIEDMONT WHERE LOW LEVEL WNW FLOW
AND LOWER-MIDDLE 60S SURFACE DEWPOINTS ARE FORECAST TO PREVAIL.
PROJECTED 15-25 KTS OF DEEP LAYER SHEAR FAVORS MULTI-CELL CLUSTERS
CAPABLE OF KNOCKING DOWN A FEW TREES...AND PRODUCING LOCALLY HEAVY
RAIN. SHOWERS AND STORMS ARE APT TO LINGER INTO THE FIRST HALF OF
THE NIGHT IN THE COASTAL PLAIN...INVOF THE SURFACE BOUNDARY AND
PROBABLE OUTFLOW... BEFORE THE PARENT SHORTWAVE TROUGH AND
ASSOCIATED LARGER SCALE FORCING FOR ASCENT LIFT NORTHEAST OF OUR
REGION..AND NOCTURNAL COOLING/PRIOR CONVECTIVE OVERTURNING
STABILIZES THE ENVIRONMENT. WARM WITH HIGHS 89 TO 94...AND LOWS IN
THE UPPER 60S TO LOWER 70S.
THU AND THU NIGHT: NWP GUIDANCE HAS TRENDED MORE AMPLIFIED WITH THE
SECOND SHORTWAVE TROUGH FOR THU. SO WHILE THE BEST LOW LEVEL
CONVERGENCE AND MOISTURE WILL EXIST OVER SOUTHEASTERN NC...LOW LEVEL
MOISTURE ON THE COOL SIDE OF THE FRONT - IN STILL RELATIVELY-MOIST
NORTHEAST FLOW WITH DEWPOINTS IN THE UPPER 60S - WILL LIKELY PROVE
SUPPORTIVE OF SCATTERED TO PERHAPS NUMEROUS STORMS FROM NEAR KMEB TO
KGSB...WITH MORE WIDELY SCATTERED DEVELOPMENT TO THE NORTHWEST.
COOLER IN THE AFOREMENTIONED POST-FRONTAL NE FLOW...WITH HIGHS
RANGING FROM THE LOWER 80S NW PIEDMONT TO UPPER 80S SANDHILLS AND
SOUTHERN COASTAL PLAIN. LOWS AGAIN GENERALLY INT HE UPPER 60S TO
LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
WEDNESDAY THROUGH THURSDAY:
THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO
UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF
LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS
THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH
CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY
NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY
BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC
STATES.
DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN
THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION
OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE
HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND
COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE
FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS
COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL
PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG
TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN
NC.
NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S
SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE.
FRIDAY THROUGH SUNDAY:
FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE...
WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL
DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW
ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING.
ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE
SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE
LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS
EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65
TO 70.
TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND
ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY
NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO
30 PERCENT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1230 PM MONDAY...
MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY
BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN
SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX
OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE...
SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING
FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE
EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT
THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES
MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION
DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED
02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED
TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE
CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN
LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A
BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT.
LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH
WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR
FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/
STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY
AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE
ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...HARTFIELD
SHORT TERM...MWS
LONG TERM...CBL
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
253 PM EDT MON JUL 22 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S.
THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER
CENTRAL NORTH CAROLINA THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 250 PM MONDAY...
THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS
THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT...
AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH
ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS.
THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG
AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL
LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS
OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS
SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF
2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE
WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG
THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH
CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED
IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST
CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER
TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH
OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH
THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE
COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP
TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS
ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW
LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD
MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE
WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z...
AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES
TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN
THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED
(AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING...
WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO
CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND
A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO
SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK
DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH
DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK
ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE
THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW
DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE...
69-73.
FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE...
FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING
ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF
THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL
AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE
AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL
DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY
AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY
AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING
VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED
ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP
PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED
WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL
MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER.
EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS
THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY
NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG
OVERNIGHT. -GIH
&&
.SHORT TERM / /...
AS OF 300 AM MONDAY...
TO BE UPDATED SHORTLY.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
WEDNESDAY THROUGH THURSDAY:
THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO
UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF
LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS
THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH
CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY
NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY
BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC
STATES.
DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN
THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION
OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE
HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND
COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE
FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS
COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL
PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG
TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN
NC.
NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S
SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE.
FRIDAY THROUGH SUNDAY:
FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE...
WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL
DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW
ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING.
ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE
SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE
LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS
EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65
TO 70.
TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND
ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY
NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO
30 PERCENT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1230 PM MONDAY...
MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY
BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN
SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX
OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE...
SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING
FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE
EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT
THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES
MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION
DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED
02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED
TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE
CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN
LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A
BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT.
LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH
WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR
FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/
STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY
AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE
ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...HARTFIELD
SHORT TERM...WSS
LONG TERM...CBL
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1230 PM EDT MON JUL 22 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S.
THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER
CENTRAL NORTH CAROLINA THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM MONDAY...
REST OF TODAY: VERY MOIST AIR MASS IN PLACE AS NOTED BY 12Z GSO/MHX
SOUNDINGS AND BLENDED TPW IMAGERY... WITH PW RANGING FROM 2.0-2.2
INCHES WEST TO EAST... ALTHOUGH VALUES ARE SLIGHTLY LOWER TO OUR
WEST. LATEST SURFACE ANALYSIS SHOWS THE NEARLY STATIONARY SYNOPTIC
FRONTAL ZONE FROM IA EAST ACROSS NRN IL/IN/OH TO PA/MA. A WEAK LOW
IS EVIDENT OVER SCENTRAL VA WITH TRAILING WEAK TROUGHING THROUGH
CENTRAL NC... AND A MORE PROMINENT LOW AND TROUGH OVER SRN IL/SE
MO/NW AR. THE LATTER FEATURE IS ASSOCIATED WITH A POTENT MID LEVEL
SHORTWAVE TROUGH THAT IS ON PACE TO APPROACH OUR AREA LATE TONIGHT.
ANOTHER UPPER LEVEL WAVE NOW OVER THE AL/GA BORDER IS EXPECTED TO
TRACK ACROSS FAR SRN AND SE NC THIS EVENING. MODELS ARE NOT IN GREAT
AGREEMENT ON THE TIMING AND EXTENT OF CONVECTION THIS AFTERNOON/
EVENING. THE 4KM WRF-ARW/WRF-NMM AND HRRR DEPICT JUST SCATTERED
COVERAGE IN THE EARLY AFTERNOON IN THE ERN CWA... WHERE THE CINH HAS
VANISHED AND WHERE MLCAPE HAS ALREADY CLIMBED NEAR 1000 J/KG. BUT
THE DEEP LAYER SHEAR IS QUITE POOR (UNDER 15 KTS) AND EXPECTED TO
REMAIN SO THROUGH THE DAY... NOT SUPPORTIVE OF STRONG ORGANIZED
CONVECTION. PW WILL ALSO BE DROPPING A BIT THIS AFTERNOON... AND THE
STRONG MISS VALLEY WAVE SHIFTING EASTWARD MAY HELP DEAMPLIFY THE
AL/GA WAVE AS IT CROSSES THE CAROLINAS. WILL ADJUST POPS A BIT
THROUGH THE AFTERNOON TO FOCUS THE BETTER COVERAGE (30-40%) IN THE
EAST... WHERE MOISTURE AND INSTABILITY IS EXPECTED TO BE BETTER
BENEATH WEAK UPPER-LEVEL DPVA... WITH LOWER POPS OF 20-30% IN THE
WRN CWA. LOCALLY HEAVY RAIN IS STILL POSSIBLE WITH WARM LAYERS
(LCL-0C) OF 3.5-3.8 KM... AND ANY ADDITIONAL RAIN IN AREAS THAT SAW
A LOT YESTERDAY (SUCH AS THE GREENSBORO AREA) COULD EASILY SEE QUICK
FLOODING TODAY. FREQUENT LIGHTNING IS STILL A SECONDARY CONCERN...
ALTHOUGH THE MARGINAL -10C TO -30C CAPE PEAKING AT 500 J/KG IS NOT
AS HIGH AS IN SOME OF THE PROLIFIC LIGHTNING EVENTS WE`VE HAD
RECENTLY. TEMP RISE SO FAR HAS BEEN GREATLY TEMPERED BY STUBBORN
STRATOCU OVER MUCH OF CENTRAL NC... WITH ONLY ERN/SRN SECTION SEEING
SOME HOLES IN THE CLOUDS. EXPECT THIS WILL START TO MIX OUT SHORTLY
(BASED ON PILOT REPORTS THAT THIS DECK IS 500-1000 FT THICK)... BUT
WITH THE DELAYED INSOLATION... WILL STILL NEED TO TRIM A FEW DEGREES
OFF HIGHS... GOING WITH 85-90. -GIH
WHILE BULK OF CONVECTION WILL DIMINISH IN THE EVENING WITH LOSS OF
HEATING...APPROACH OF THE MID-UPPER LEVEL TROUGH WILL LIKELY
MAINTAIN A FEW SHOWERS/STORMS INTO THE OVERNIGHT HOURS. CONTINUED
MUGGY TONIGHT WITH MIN TEMPS NEAR 70-LOWER 70S. -WSS
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 300 AM MONDAY...
EXPECT A CONTINUATION OF THE UNSETTLED WEATHER PATTERN TUESDAY DUE
TO PRESENCE OF MID-UPPER LEVEL TROUGH OVER THE CAROLINAS THOUGH
FOCUS MAY BE MORE IN THE EAST VERSUS WEST. SHORT TERM MODEL GUIDANCE
SUGGEST WESTERLY 850MB FLOW DEVELOPING LATE TODAY INTO TUESDAY WITH
A 850MB TROUGH CROSSING THE REGION TUESDAY AFTERNOON. RH CROSS
SECTION SUGGEST THE AIR MASS DRYING OUT ABOVE 700MB/10K FT DURING
THE COURSE OF THE AFTERNOON...ESPECIALLY WEST OF HIGHWAY 1. THE
DOWNSLOPE FLOW IN THE WAKE OF THIS SYSTEM AND AN AIR MASS NOT AS
MOIST MAY LIMIT/INHIBIT CONVECTIVE DEVELOPMENT IN THE WEST ON
TUESDAY. WITH TROUGH CROSSING THE EAST DURING MAX HEATING...STILL
EXPECT AT A MINIMUM 50 PERCENT COVERAGE. PRESENCE OF DRIER AIR ALOFT
MAY LEAD TO EVAPORATIVE COOLING IN VICINITY OF THUNDERSTORM
DOWNDRAFTS...LEADING TO STRONG/LOCALLY DAMAGING WINDS WITH THE
STRONGER CELLS. MAJORITY OF THE CONVECTION WILL DISSIPATE SHORTLY
AFTER SUNSET THOUGH THE APPROACH OF A SECONDARY TROUGH IN THE FLOW
ALOFT MAY TRIGGER ADDITIONAL ACTIVITY LATE TUESDAY NIGHT-EARLY
WEDNESDAY MORNING.
THE DRIER AIR MASS ALOFT SHOULD ALLOW FOR PERIODS OF PARTIAL
SUNSHINE. THIS MAY LEAD TO AFTERNOON TEMPS A COUPLE OF DEGREES
WARMER THAN TODAY. EXPECT MAX TEMPS NEAR 90 TO LOWER 90S AREAWIDE.
MIN TEMPS NEAR 70-LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
WEDNESDAY THROUGH THURSDAY:
THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO
UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF
LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS
THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH
CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY
NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY
BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC
STATES.
DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN
THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION
OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE
HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND
COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE
FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS
COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL
PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG
TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN
NC.
NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S
SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE.
FRIDAY THROUGH SUNDAY:
FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE...
WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL
DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW
ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING.
ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE
SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE
LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS
EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65
TO 70.
TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND
ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY
NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO
30 PERCENT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1230 PM MONDAY...
MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY
BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN
SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX
OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE...
SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING
FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE
EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT
THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES
MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION
DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED
02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED
TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE
CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN
LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A
BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT.
LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH
WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR
FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/
STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY
AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE
ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...CBL
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
601 PM EDT MON JUL 22 2013
.SYNOPSIS...
MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH
ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS.
&&
.NEAR TERM /THROUGH TUESDAY/...
6PM UPDATE...TWEAKED POP GRIDS THIS EVENING BASED ON CURRENT RADAR
TRENDS. OTHERWISE...MADE NO MAJOR CHANGES TO THE FORECAST.
PREVIOUS DISCUSSION FOLLOWS...
WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND
KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST
RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY
SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA
BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS
WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO
WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE
AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE
TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT
THRU TONIGHT.
UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING
IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF
AREA AFTER 09Z WITH PCPN THREAT DIMINISHING.
THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE
UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY
AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW
FLOW ALOFT.
ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA
SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
COLD FRONT SWINGS THROUGH TUESDAY NIGHT AS 5H TROF SWINGS THROUGH
AT THE MID LEVELS. CARRIED LIKELY POPS AS THERE WILL BE DECENT
DYNAMIC FORCING COUPLED WITH PLENTY OF A AVAILABLE MOISTURE.
HOWEVER...CHANCES FOR SEVERE WEATHER ASSOCIATED WITH THIS FEATURE
WILL BE LIMITED DUE TO THE LACK OF DAYTIME HEATING DURING THE
OVERNIGHT HOURS.
AS HIGH PRESSURE BUILDS IN WEDNESDAY...BULK OF MOISTURE WILL BE
SHUNTED TO THE EAST...LEADING TO A DRYING TREND. SHOULD SEE A
NOTICEABLE DECREASE IN CONVECTIVE ACTIVITY WEDNESDAY AND THURSDAY
AS LOW AND MID LEVEL COOL POOL HELPS TO STABILIZE THE ATMOSPHERE.
LEFT CHANCE POPS IN FOR MOUNTAINS AS HEATING IN ELEVATED TERRAIN
COULD STILL LEAD TO SOME CONVECTIVE DEVELOPMENT.
WILL SEE A COOLING TREND THIS PERIOD. GOING WITH MODEL BLEND FOR
TEMPERATURES THIS PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
DRIER AIR MOVES IN TO CLOSE OUT THE WEEK AS TROUGH DIGS OVER THE
GREAT LAKES SATURDAY AND SUNDAY. GFS AND EURO MODELS HANDLING
FEATURES IN SEPARATE FASHION AND DEFERRED TO HPC GRIDS FOR
EXTENDED PERIOD. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE
TEMPERATURES.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING
IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END
VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH
PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP
OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB
AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA.
MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY
IN FOR NOW.
LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU
FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS
AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY
OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE
CONDITIONS MAY VARY THIS AFTERNOON AND EVENING.
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.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
CRW CONSISTENCY H H H H H H M M M M L L
HTS CONSISTENCY H H H H M L M M M M L L
BKW CONSISTENCY H H H H H H H H M M M H
EKN CONSISTENCY H H H H M M H H H H L M
PKB CONSISTENCY M M L L M M M H H L M M
CKB CONSISTENCY M M M M H H M H M M L M
AFTER 00Z WEDNESDAY...
IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/30
NEAR TERM...SL/30
SHORT TERM...KMC
LONG TERM...KMC
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
339 PM EDT MON JUL 22 2013
.SYNOPSIS...
MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH
ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS.
&&
.NEAR TERM /THROUGH TUESDAY/...
WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND
KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST
RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY
SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA
BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS
WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO
WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE
AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE
TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT
THRU TONIGHT.
UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING
IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF
AREA AFTER 09Z WITH PCPN THREAT DIMINISHING.
THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE
UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY
AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW
FLOW ALOFT.
ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA
SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
COLD FRONT SWINGS THROUGH TUESDAY NIGHT AS 5H TROF SWINGS THROUGH
AT THE MID LEVELS. CARRIED LIKELY POPS AS THERE WILL BE DECENT
DYNAMIC FORCING COUPLED WITH PLENTY OF A AVAILABLE MOISTURE.
HOWEVER...CHANCES FOR SEVERE WEATHER ASSOCIATED WITH THIS FEATURE
WILL BE LIMITED DUE TO THE LACK OF DAYTIME HEATING DURING THE
OVERNIGHT HOURS.
AS HIGH PRESSURE BUILDS IN WEDNESDAY...BULK OF MOISTURE WILL BE
SHUNTED TO THE EAST...LEADING TO A DRYING TREND. SHOULD SEE A
NOTICEABLE DECREASE IN CONVECTIVE ACTIVITY WEDNESDAY AND THURSDAY
AS LOW AND MID LEVEL COOL POOL HELPS TO STABILIZE THE ATMOSPHERE.
LEFT CHANCE POPS IN FOR MOUNTAINS AS HEATING IN ELEVATED TERRAIN
COULD STILL LEAD TO SOME CONVECTIVE DEVELOPMENT.
WILL SEE A COOLING TREND THIS PERIOD. GOING WITH MODEL BLEND FOR
TEMPERATURES THIS PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
DRIER AIR MOVES IN TO CLOSE OUT THE WEEK AS TROUGH DIGS OVER THE
GREAT LAKES SATURDAY AND SUNDAY. GFS AND EURO MODELS HANDLING
FEATURES IN SEPARATE FASHION AND DEFERRED TO HPC GRIDS FOR
EXTENDED PERIOD. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE
TEMPERATURES.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING
IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END
VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH
PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP
OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB
AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA.
MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY
IN FOR NOW.
LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU
FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS
AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY
OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE
CONDITIONS MAY VARY THIS AFTERNOON AND EVENING.
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.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
CRW CONSISTENCY H H H H H H M M M M L L
HTS CONSISTENCY H H H H M L M M M M L L
BKW CONSISTENCY H H H H H H H H M M M H
EKN CONSISTENCY H H H H M M H H H H L M
PKB CONSISTENCY M M L L M M M H H L M M
CKB CONSISTENCY M M M M H H M H M M L M
AFTER 18Z TUESDAY...
IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/30
NEAR TERM...30
SHORT TERM...KMC
LONG TERM...KMC
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
233 PM EDT MON JUL 22 2013
.SYNOPSIS...
MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH
ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS.
&&
.NEAR TERM /THROUGH TUESDAY/...
WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND
KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST
RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY
SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA
BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS
WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO
WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE
AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE
TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT
THRU TONIGHT.
UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING
IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF
AREA AFTER 09Z WITH PCPN THREAT DIMINISHING.
THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE
UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY
AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW
FLOW ALOFT.
ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA
SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
EXCEPT FOR THE NAM/SREF SUITE OF MODELS WHICH ARE SLOW OUTLIERS
THERE IS GROWING AGREEMENT AMONG THE MODELS OF A FASTER PROGRESSION
OF THE COLD FRONT TUESDAY NIGHT...AND OF A QUITE WEAK SECONDARY
FRONT WEDNESDAY.
FIRST...EXPECT A RAPID DECREASE IN CONVECTION TUESDAY AS AN UPPER
DISTURBANCE EXITS AND TAKES MUCH OF THE RICH MOISTURE WITH IT.
AGAIN...THE NAM IS A VERY SLOW OUTLIER EXITING THIS SYSTEM AND WAS
NOT USED. WILL PAINT HIGH POPS EARLY IN MOUNTAINS BUT DECREASE THAT
DURING TUESDAY MORNING. WILL KEEP LOWER POPS TUESDAY AFTERNOON WITH
REMAINING LOW LEVEL MOISTURE AND HEATING TO DESTABILIZE THE
ATMOSPHERE WELL AHEAD OF THE AFOREMENTIONED COLD FRONT...ESPECIALLY
MOUNTAINS WITH AN ELEVATED HEAT SOURCE.
WILL RAMP POPS UP AGAIN TUESDAY NIGHT WITH THE FRONT...GOING LIKELY
FOR AN ORGANIZED BAND OF CONVECTION ALONG THE FRONT. HOWEVER...LESS
RISK OF WATER PROBLEMS WITH THIS FEATURE AS PW`S WILL BE MUCH LESS
THAN WE ARE CURRENTLY EXPERIENCING. WILL KEEP LOW POPS IN FOR MAINLY
WEDNESDAY AFTERNOON AS THE SECONDARY FRONT DROPS SOUTHEASTWARD
ACROSS THE AREA...MOSTLY IN MOUNTAINS.
HIGH PRESSURE FINALLY BUILDS IN FOR THURSDAY WITH DRIER AND COOLER
AIR BECOMING ESTABLISHED. STILL LINGER JUST A LOW CHANCE POP MOSTLY
MOUNTAINS FOR AN AFTERNOON SHOWER PER SQUEEZING OUT ANY LINGERING LOW
LEVEL MOISTURE WITH UPSLOPE FLOW AND MODEST COLD ADVECTION ALOFT.
LOOK FOR A MODEST COOLING TREND THIS PERIOD...BUT A SIGNIFICANT
DRYING OUT. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
STILL TRYING TO BRING DRIER AIR THURSDAY INTO FRIDAY. DEEPENING
500 MB TROF OVER EASTERN CANADA MAY PULL ANOTHER DISTURBANCES SE
ON SATURDAY.
NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING
IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END
VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH
PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP
OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB
AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA.
MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY
IN FOR NOW.
LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU
FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS
AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY
OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE
CONDITIONS MAY VARY THIS AFTERNOON AND EVENING.
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.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H M M M M
HTS CONSISTENCY H H H H H H M L M M M H
BKW CONSISTENCY H H H H H H H H H H M M
EKN CONSISTENCY H H H H H H M M H H H H
PKB CONSISTENCY H H M M L L H H H H H L
CKB CONSISTENCY H M M M M M H H M H H H
AFTER 18Z TUESDAY...
IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...KMC/30
NEAR TERM...30
SHORT TERM...JMV
LONG TERM...KTB
AVIATION...30
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1242 PM CDT MON JUL 22 2013
.UPDATE...
18Z TAF DISCUSSION.
&&
.AVIATION...
MORNING MCS HAS GENERALLY FALLEN APART BUT SOME -SHRA WILL AFFECT
CSV THROUGH THE AFTERNOON. SOME REDEVELOPMENT OF -SHRA IS POSSIBLE
INTO THE EVENING AT CSV. CIGS RANGE FROM IFR AT CKV TO VFR AT CSV
CURRENTLY...BUT GENERAL IMPROVEMENT TO MVFR THIS AFTERNOON AND VFR
BY EVENING IS EXPECTED. THE WIDESPREAD RAINFALL SHOULD RESULT IN
SOME FOG FORMATION AROUND SUNRISE TUESDAY MORNING WITH MVFR/IFR
VIS. LIGHT SOUTHWEST TO WEST WINDS ARE ANTICIPATED THROUGHOUT THE
TAF PERIOD.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 1022 AM CDT MON JUL 22 2013/
DISCUSSION...
HAVE UPDATED ZONES AND GRIDS TO REDUCE POPS OVER THE NORTHWEST.
RAIN IS BEGINNING TO TAPER OFF OVER THE NORTHWEST AND EXPECT THIS
TREND WILL CONTINUE.
BOYD
PREV DISCUSSION... /ISSUED 922 AM CDT MON JUL 22 2013/
MESOSCALE UPDATE...
ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS
HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE
NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL
SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN
ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND
UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE
BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE
AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT
SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON.
BOYD
PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/
UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S.
AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH
MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID
STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF
OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH
SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS
EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG
TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING.
PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/
DISCUSSION...
THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN
RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE
WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF
DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE
MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN
FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR
THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH
VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL
REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT
FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY
THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE
NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS
AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW
WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST
15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO
MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT
PERIOD OF TIME.
THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS
PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY
LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY
TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE
HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM
OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES
WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD.
WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND
FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP
MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS.
WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF
OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND
UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI
VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS
STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN
REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT
AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS.
UNGER
AVIATION...06Z TAF DISCUSSION.
UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST
OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA
TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY
IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY
SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE
CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR
TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED
AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD
HANG ON.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
133 PM MDT MON JUL 22 2013
.SYNOPSIS...
WE CAN EXPECT A WEAK MONSOONAL PATTERN FOR MOST OF THE WORK WEEK.
IN THIS CASE THE PATTERN FAVORS HEAVIER RAINFALL FOR AREAS FROM
THE CONTINENTAL DIVIDE WEST...BUT AFTERNOON OR NIGHTTIME
THUNDERSTORMS ARE POSSIBLE ANYWHERE IN THE FORECAST AREA EACH
AFTERNOON AND EVENING.
FOR THE WEEKEND...A BACKDOOR COLD FRONT WILL FRILT WITH OUR AREA
WHICH SHOULD SERVE TO DRAW ADDITIONAL TROPICAL MOISTURE INTO THE
REGION AND RESULT IN AN INCREASED CHANCE OF SHOWERS AND
THUNDERSTORMS.
TEMPERATURES DURING UPCOMING WEEK WILL RUN WITH A FEW DEGREES OF
NORMAL.
&&
.DISCUSSION...
UPPER HIGH IS BEGINNING TO BUILD EAST TO COVER THE CWA FOR THE
UPCOMING WEEK. INVERTED TROUGH SLIDING WEST OVER NORTHERN MEXICO
MAY PROVIDE A LITTLE EXTRA DYNAMICS/MOISTURE OVER THE SOUTHERN TIER.
LAST AVBL HRRR AND 12Z SPC 4KM RUN BOTH SHOW CLUSTER OF STORMS
IMPACTING SW PORTIONS OF AREA TONIGHT...SO HAVE RAISED POPS IN
THAT AREA,
OTHERWISE EXPECT MAINLY A LOW GRADE MONSOONAL PATTERN THROUGH
DAYTIME FRIDAY. THERE MAY BE AN UPTICK OF CONVECTION WEDNESDAY
WHERE THE ORIENTATION OF THE UPPER HIGH AND THE INVERTED TROUGH
ALLOWS A LITTLE EXTRA MOISTURE AND REDUCED STABILITY OVER THE AREA.
THE LARGER QUESTION FOR ME IS WHETHER A BACKDOOR FRONT MAKES IT
INTO THE AREA FOR THE WEEKEND. WEEKEND RUNS OF THE GFS/ECMWF WERE
VERY AGGRESSIVE IN BRINGING THE FRONT INTO THE AREA. LATER RUNS OF
THE GFS IN PARTICULAR HAVE BACKED AWAY FROM FROPA OVER THE AREA...
HOWEVER CMC 12Z RUN STILL HAS A STRONG PASSAGE. SINCE I HAVE LITTLE
TRUST IN GFS HANDLING OF BACKDOORS THIS FAR OUT AND THAT SURFACE
TROUGHING WILL ALLOW A CHANNEL OF MOISTURE TO MOVE TOWARD THE
FRONT REGARDLESS OF ITS FINAL POSITION...I HAVE BUMPED POPS UP
FOR THE WEEKEND AFTERNOONS. IF THE FRONT MAKES IT INTO THE REGION
THERE WOULD LIKELY BE AN INCREASE FLOOD RISK AND POSSIBLE SEVERE
WEATHER AS WELL.
&&
.AVIATION...VALID 23/00Z-24/00Z.
SCATTERED TSRA THRU 06Z OVER THE MOUNTAINS WITH ISOLATED TO WIDELY
SCATTERED TSRA IN THE LOWLANDS. STORMS WILL TEND TO DRIFT TOWARDS
THE W OR WSW. MOSTLY VFR CONDITIONS ARE EXPECTED WITH THE EXCEPTION
OF BRIEF EXCURSIONS INTO MVFR/IFR CONDITIONS IN AND AROUND
THUNDERSTORMS.
&&
.FIRE WEATHER...
A HIGH PRESSURE RIDGE ALOFT REMAINS ANCHORED OVER THE REGION WITH
AMPLE LOW LEVEL MOISTURE IN PLACE AT THE SURFACE. THIS WILL RESULT
IN SCATTERED TO WIDELY SCATTERED AFTERNOON AND EVENING THUNDERSTORMS
THE NEXT SEVERAL DAYS. CLOSER INSPECTION REVEALS A WEAK UPPER
DISTURBANCE TRACKING SLOWLY WESTWARD TO OUR SOUTH ACROSS NORTHERN
MEXICO. THIS WILL LIKELY ENHANCE STORM CHANCES NEAR THE
INTERNATIONAL BORDER AND AREAS WEST OF THE RIO GRANDE THIS EVENING
AND TONIGHT. THIS FEATURE WILL EVENTUALLY EXUDE IT`S INFLUENCE
FURTHER NORTH INTO THE REGION MID TO LATE WEEK AS THE RIDGE BEGINS
TO WEAKEN. AS A RESULT A GREATER COVERAGE OF WETTING RAINFALL WILL
BE POSSIBLE AREA WIDE. THIS TREND WILL CONTINUE INTO THE WEEKEND.
WITH LOW LEVEL MOIST AIR IN PLACE MINIMUM RH VALUES WILL CONTINUE TO
RUN AROUND 30 PERCENT FOR THE LOWLANDS AND BETWEEN 40 AND 50 PERCENT
ACROSS THE HIGHER ELEVATIONS WITH EXCELLENT RECOVERIES OVERNIGHT FOR
THE NEXT SEVERAL DAYS. MEANWHILE HAINES INDICES WILL REMAIN LOW TO
VERY LOW ACROSS THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 73 93 75 93 75 / 30 20 20 20 30
SIERRA BLANCA 69 91 71 92 71 / 30 20 20 30 20
LAS CRUCES 70 93 71 91 70 / 30 20 20 20 40
ALAMOGORDO 70 95 72 95 71 / 30 20 20 30 40
CLOUDCROFT 50 71 52 71 52 / 30 30 20 40 40
TRUTH OR CONSEQUENCES 69 94 71 93 70 / 30 20 20 30 40
SILVER CITY 64 85 65 85 62 / 40 40 30 30 40
DEMING 69 92 70 91 68 / 30 20 20 20 40
LORDSBURG 67 91 69 91 66 / 30 30 30 30 40
WEST EL PASO METRO 74 93 76 92 75 / 30 20 20 20 30
DELL CITY 68 94 69 95 69 / 20 10 20 20 30
FORT HANCOCK 73 94 73 95 73 / 30 20 30 30 30
LOMA LINDA 65 88 66 88 67 / 40 20 20 20 30
FABENS 71 92 73 93 73 / 40 20 30 20 30
SANTA TERESA 71 92 71 91 71 / 40 20 20 20 30
WHITE SANDS HQ 72 94 74 93 74 / 40 20 20 20 30
JORNADA RANGE 66 94 68 93 67 / 40 20 20 20 40
HATCH 70 91 73 89 71 / 30 20 20 20 40
COLUMBUS 69 91 70 90 69 / 40 20 20 20 40
OROGRANDE 69 95 70 95 73 / 30 20 20 20 30
MAYHILL 57 81 59 80 59 / 30 40 20 30 40
MESCALERO 56 85 56 84 56 / 30 30 20 40 40
TIMBERON 57 78 58 78 58 / 30 30 20 30 40
WINSTON 59 84 61 85 60 / 30 30 30 30 40
HILLSBORO 66 89 68 87 67 / 30 30 30 30 40
SPACEPORT 69 94 69 92 68 / 30 20 20 20 30
LAKE ROBERTS 61 85 62 85 60 / 40 50 30 40 50
HURLEY 64 87 65 86 63 / 40 30 30 30 40
CLIFF 65 92 66 92 62 / 30 40 40 30 40
MULE CREEK 58 88 59 88 58 / 30 40 40 40 40
FAYWOOD 65 86 68 87 64 / 30 30 30 30 40
ANIMAS 67 89 68 89 66 / 30 30 30 30 40
HACHITA 68 89 68 89 66 / 30 30 20 20 40
ANTELOPE WELLS 66 86 66 85 66 / 30 30 30 30 40
CLOVERDALE 63 81 64 80 64 / 40 40 30 40 50
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
02/27
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
408 PM CDT MON JUL 22 2013
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 407 PM CDT MON JUL 22 2013
FORECAST UPDATED FOR THE SEVERE THUNDERSTORM WATCH WHICH COVERS
MUCH OF THE FORECAST AREA. WILL DEAL WITH THE FOX CITIES AND
LAKESHORE REGION AROUND MID EVENING IF NEEDED.
&&
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 220 PM CDT MON JUL 22 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD
FRONT MOVING SOUTHEAST OVER WESTERN LAKE SUPERIOR...WESTERN
WISCONSIN TO NORTHWEST IOWA. THOUGH UPPER SUPPORT IS LARGELY NORTH
OF LAKE SUPERIOR. THERE MAY BE A WEAK IMPULSE OVER NORTHWEST
WISCONSIN THAT HELPED CONVECTION FIRE EARLIER THIS AFTERNOON.
THOUGH NOT THE 2500 ML CAPES THAT WERE EXPECTED EARLIER...ML CAPES
HAVE RISEN INTO THE 1500-2000 J/KG RANGE WHICH WILL BE MORE THAN
SUFFICIENT FOR SEVERE STORMS INTO NORTH-CENTRAL WISCONSIN LATER THIS
AFTERNOON...PROVIDED THAT THIS PESKY INHIBITION CAN GET WHITTLED
AWAY. DESPITE 0-6KM SHEAR OF 35 KTS AND DECENT LOW LEVEL
SHEAR...THE FRONT IS STRUGGLING TO PRODUCE GOOD THUNDERSTORMS EVEN
WITH DEWPOINTS IN THE UPPER 60S AHEAD OF IT. BUT POTENTIAL WILL
REMAIN FOR SEVERE STORMS TO DEVELOP AS INHIBITION IS FURTHER ERODED.
STORMS SHOULD BE ARRIVING INTO N-C WISCONSIN BY 21Z AND IRON
MOUNTAIN TO WAUSAU BY 00Z. SEVERE WEATHER IS THE MAIN FORECAST
CONCERN.
TONIGHT...THE COLD FRONT WILL DRIVE SOUTHEAST ACROSS ALL BUT FAR
NORTH-CENTRAL WISCONSIN THIS EVENING...AND EXIT AROUND MIDNIGHT OR
SHORTLY THEREAFTER. ASSUMING SEVERE STORMS DEVELOP...STORMS SHOULD
BE SURFACE BASED INTO THE EVENING WITH ML CAPES AROUND 1.5-2K J/KG
AND 0-6KM BULK SHEAR VALUES AROUND 30-35KTS. STORMS SHOULD GROW
MORE ELEVATED WITH TIME THIS EVENING WITH CAPES FALLING AS A
RESULT. DECENT 0-1KM HELICITY SHOULD BE ABLE TO SUPPORT ROTATING
UPDRAFTS THAT WILL KEEP A FEW STORMS ON THE STRONGER SIDE
THOUGH...SO THE SEVERE THREAT SHOULD CONTINUE INTO THE MID-EVENING
HOURS. AS STORM INTENSITY GRADUALLY DIMINISHES...THE MAIN THREATS
WILL TRANSITION TO A DAMAGING WIND THREAT...WHICH SHOULD REACH INTO
THE EASTERN SECTIONS OF THE FORECAST AREA LATE IN THE EVENING.
BEHIND THE FRONT...PLENTY OF STRATO-CU UPSTREAM OVER MINNESOTA WILL
ARRIVE LATE TONIGHT. WILL KEEP PARTLY TO MOSTLY CLOUDY CONDITIONS
GOING THROUGH LATE TONIGHT BEFORE MOISTURE THINS OUT.
TUESDAY...DRIER AIR WILL BE FILTERING SOUTH ACROSS MUCH OF CENTRAL
AND NORTHEAST WISCONSIN DURING THE MORNING...THOUGH LINGERING
MOISTURE OVER THE UPPER PENINSULA AND FAR NORTHERN WISCONSIN MAY
KEEP SCT-BKN STRATO-CU AROUND A LITTLE LONGER THAN FURTHER SOUTH.
NORTHERLY WINDS WILL BE DRIVING IN A COOLER AND LESS HUMID AIRMASS.
HIGH TEMPS WILL ONLY REACH FROM THE UPPER 60S TO MID 70S UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 220 PM CDT MON JUL 22 2013
UPPER PATTERN DURING PERIOD CHARACTERIZED BY NW UPPER FLOW AND
OCNL SHORTWAVE TROFS MOVING THROUGH MEAN TROF POSITION. EACH
SHORTWAVE TROF--MID WEEK AND END OF THE WEEK--WILL BRING SCATTERED
CONVECTION AND COOLER AIR. STRONGEST OF THE SYSTEMS NEXT WEEKEND
WILL BRING CHILLY AIR INTO STATE ON SATURDAY. WHILE UPPER FLOW IS
CYCLONIC...SURFACE ANTICYCLONE AND DRY LOW-LEVELS SHOULD MINIMIZE
THREAT FOR WIDESPREAD INSTABILITY SHOWERS.
TEMP FORECAST THROUGH THE PERIOD GENERALLY A BLEND OF PREVIOUS
FORECAST AND BEST PERFORMING 22/12Z MODELS. MIN TEMPS WED AM COULD
SLIP TO 40 F IN THE BOGS OF NORTH-CENTRAL WISC.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1237 PM CDT MON JUL 22 2013
A STRONG COLD FRONT WILL BRING A SCT TO BKN LINE OF
THUNDERSTORMS ACROSS NORTH-CENTRAL WISCONSIN MID TO LATE
AFTERNOON...AND NORTHEAST WISCONSIN EARLY TO MID EVENING. STRONG
GUSTY WINDS AND LARGE HAIL ARE POSSIBLE WITH THESE STORMS...BUT THAT
WILL BE MORE OF A THREAT OVER NORTH-CENTRAL WISCONSIN THAN FURTHER
EAST. BEHIND THE FRONT...PLENTY OF MVFR CIGS OVER NORTH DAKOTA AND
MINNESOTA...AND WILL BRING THEM INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN TONIGHT. DRIER AIR WILL EVENTUALLY ARRIVE LATE TONIGHT TO
SCOUR OUT THE MVFR CIGS...WHICH WILL LEAVE GOOD FLYING WEATHER FOR
TUESDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........TDH
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
325 PM CDT MON JUL 22 2013
.VERY SHORT TERM...LATE THIS AFTERNOON...TONIGHT AND
TUESDAY...FORECAST CONFIDENCE IS MEDIUM.
MAIN FORECAST ISSUE CONTINUES TO BE AREAL COVERAGE OF STORMS AND
SEVERE RISK WITH PASSAGE OF COLD FRONT LATE THIS AFTERNOON AND THIS
EVENING. LATEST RUNS OF THE HRRR AND WRF 4KM WITH LAPS HIGH
RESOLUTION MODELS SHOW CONVECTION ASSOCIATED WITH THE FRONT MOVING
SOUTHEAST INTO THE NORTHWEST PORTIONS OF THE FORECAST AREA BY 00Z
TUESDAY...THEN FALLING APART AS THEY SHIFT FURTHER
SOUTHEAST...EXITING THE FAR SOUTHEAST COUNTIES BY 05Z TUESDAY.
NAM/GFS/ECMWF/CANADIAN MODELS ALL SHOW QPF WITH THE FRONTAL PASSAGE
THIS EVENING...THOUGH 18Z NAM CONTINUES TO BE SOMEWHAT SLOWER THAN
THE OTHER MODELS WITH ITS PROGRESSION.
SOME QUESTION WITH THE AREAL COVERAGE OF STORMS...AS UPWARD VERTICAL
MOTION WITH FRONT OVER THE AREA IS MODEST COMPARED TO THE NORTHEAST
AND SOUTHWEST. STILL...ENOUGH UPWARD MOTION WITH FRONT AND PASSING
MODEST 500MB VORTICITY MAXIMUM TO BRING SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS THROUGH THE AREA THIS EVENING...ENDING
SOON AFTER MIDNIGHT.
MEAN LAYER CAPES OF 1500 TO 2500 J/KG WITH 20 TO 25 KNOTS OF DEEP
LAYER SHEAR WILL BRING A RISK FOR LARGE HAIL AND DAMAGING WINDS WITH
MAINLY MULTICELL TYPE STRUCTURES. BEST CHANCES WILL REMAIN IN THE
SLIGHT RISK AREA FROM SPC...MAINLY NORTHWEST OF A FOND DU LAC TO
MADISON TO DARLINGTON LINE. THIS IS WHERE THE SOMEWHAT BETTER DEEP
LAYER SHEAR WILL BE LOCATED. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE
WITH DECENT PRECIPITABLE WATER VALUES.
BRISK NORTH WINDS WITH COLD AIR ADVECTION BEHIND FRONTAL PASSAGE
LATER TONIGHT INTO TUESDAY WILL BRING A COOLER AND DRIER AIRMASS
INTO THE REGION. THIS IS IN ADVANCE OF HIGH PRESSURE MOVING TOWARD
THE REGION FROM THE NORTHWEST. QUIET WEATHER WITH PARTLY CLOUDY
SKIES ARE EXPECTED. BREEZY NORTH WINDS WILL KEEP TEMPERATURES
SOMEWHAT BELOW SEASONAL NORMALS...ESPECIALLY NEAR THE LAKE.
TUESDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
NW FLOW ALOFT WILL PREVAIL WITH HIGH PRESSURE CENTERED OVER WI FOR
TUE NT AND WED. A WEAK SHORTWAVE TROUGH MAY BRING SCT-BKN MID
LEVEL CLOUDS FOR A TIME WED AFTERNOON AND EVENING. AT MOST...A FEW
SPRINKLES TOWARD CENTRAL WI. THE HIGH THEN SHIFTS INTO THE ERN
GREAT LAKES FOR WED NT AND THU WHILE A SFC TROUGH MOVES INTO NW WI
ON THU. THIS IS AHEAD OF A LARGE UPPER TROUGH THAT IS DIGGING SEWD
INTO SRN MANITOBA AND ONTARIO CANADA. WEAK LOW LEVEL WARM
ADVECTION WILL DEVELOP LATE WED NT AND THU. 925 MB TEMPS YIELD SFC
TEMPS IN THE MID 70S ON WED AND UPPER 70S TO 80F FOR THU.
.LONG TERM...
FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM
THE LARGE POLAR TROUGH WILL TRACK ALONG THE NRN GRTLKS AND
CANADIAN BORDER FOR THE WEEKEND. ITS COLD FRONT WILL BRING CHANCES
OF SHOWERS AND TSTORMS FOR FRI AND SAT. VERY PLEASANT AND DRY
SUMMER WX TO PREVAIL AFTERWARD.
&&
.AVIATION/00Z TAFS/...VFR CONDITIONS ARE EXPECTED THROUGH LATE THIS
AFTERNOON ACROSS TAF SITES. SOME DIURNAL CUMULUS CLOUDS WILL LINGER
DURING THIS TIME. LAKE BREEZE WILL SHIFT WINDS TO THE SOUTHEAST AT
MILWAUKEE AND KENOSHA BY 21Z TO 22Z MONDAY. MADISON SHOULD SEE LIGHT
SOUTHWEST WINDS.
COLD FRONT WILL SLIDE SOUTHEAST THROUGH TAF SITES BETWEEN 02Z AND
06Z TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED WITH THE FRONT. A FEW MAY CONTAIN LARGE HAIL AND GUSTY
WINDS...WITH BETTER CHANCE AT MADISON...LOWER CONFIDENCE AT THE
EASTERN SITES. MVFR/IFR VISIBILITIES ARE POSSIBLE WITH ANY STORMS.
VFR CONDITIONS ARE THEN EXPECTED AFTER FRONTAL PASSAGE INTO
TUESDAY. WINDS WILL SHIFT NORTH NORTHWEST AFTER THE FRONTAL
PASSAGE...AND BECOME NORTH NORTHEAST THROUGH TUESDAY. WINDS WILL
BECOME GUSTY WITH COOLER AND DRIER AIR MOVING INTO THE REGION
DURING THIS TIME. GUSTS INTO THE 20 TO 25 KNOT RANGE ARE POSSIBLE.
$$
.MARINE...A TIGHT PRESSURE GRADIENT WILL DEVELOP LATE TONIGHT INTO
TUESDAY...AFTER THE COLD FRONTAL PASSAGE. THIS WILL RESULT IN BREEZY
NORTH TO NORTHEAST WINDS ACROSS THE NEARSHORE WATERS. FREQUENT GUSTS
TO 25 KNOTS ARE POSSIBLE LATE TONIGHT INTO TUESDAY NIGHT. THIS
SHOULD CAUSE WAVES TO BECOME HIGH...WITH ONSHORE FLOW AT TIMES. THE
WAVES SHOULD REMAIN HIGH INTO WEDNESDAY BEFORE SUBSIDING WITH WEAKER
WINDS. THUS...A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR LATE
TONIGHT INTO WEDNESDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 PM CDT WEDNESDAY FOR
LMZ643>646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD
TUESDAY NIGHT THROUGH MONDAY...GEHRING
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 220 PM CDT MON JUL 22 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD
FRONT MOVING SOUTHEAST OVER WESTERN LAKE SUPERIOR...WESTERN
WISCONSIN TO NORTHWEST IOWA. THOUGH UPPER SUPPORT IS LARGELY NORTH
OF LAKE SUPERIOR. THERE MAY BE A WEAK IMPULSE OVER NORTHWEST
WISCONSIN THAT HELPED CONVECTION FIRE EARLIER THIS AFTERNOON.
THOUGH NOT THE 2500 ML CAPES THAT WERE EXPECTED EARLIER...ML CAPES
HAVE RISEN INTO THE 1500-2000 J/KG RANGE WHICH WILL BE MORE THAN
SUFFICIENT FOR SEVERE STORMS INTO NORTH-CENTRAL WISCONSIN LATER THIS
AFTERNOON...PROVIDED THAT THIS PESKY INHIBITION CAN GET WHITTLED
AWAY. DESPITE 0-6KM SHEAR OF 35 KTS AND DECENT LOW LEVEL
SHEAR...THE FRONT IS STRUGGLING TO PRODUCE GOOD THUNDERSTORMS EVEN
WITH DEWPOINTS IN THE UPPER 60S AHEAD OF IT. BUT POTENTIAL WILL
REMAIN FOR SEVERE STORMS TO DEVELOP AS INHIBITION IS FURTHER ERODED.
STORMS SHOULD BE ARRIVING INTO N-C WISCONSIN BY 21Z AND IRON
MOUNTAIN TO WAUSAU BY 00Z. SEVERE WEATHER IS THE MAIN FORECAST
CONCERN.
TONIGHT...THE COLD FRONT WILL DRIVE SOUTHEAST ACROSS ALL BUT FAR
NORTH-CENTRAL WISCONSIN THIS EVENING...AND EXIT AROUND MIDNIGHT OR
SHORTLY THEREAFTER. ASSUMING SEVERE STORMS DEVELOP...STORMS SHOULD
BE SURFACE BASED INTO THE EVENING WITH ML CAPES AROUND 1.5-2K J/KG
AND 0-6KM BULK SHEAR VALUES AROUND 30-35KTS. STORMS SHOULD GROW
MORE ELEVATED WITH TIME THIS EVENING WITH CAPES FALLING AS A
RESULT. DECENT 0-1KM HELICITY SHOULD BE ABLE TO SUPPORT ROTATING
UPDRAFTS THAT WILL KEEP A FEW STORMS ON THE STRONGER SIDE
THOUGH...SO THE SEVERE THREAT SHOULD CONTINUE INTO THE MID-EVENING
HOURS. AS STORM INTENSITY GRADUALLY DIMINISHES...THE MAIN THREATS
WILL TRANSITION TO A DAMAGING WIND THREAT...WHICH SHOULD REACH INTO
THE EASTERN SECTIONS OF THE FORECAST AREA LATE IN THE EVENING.
BEHIND THE FRONT...PLENTY OF STRATO-CU UPSTREAM OVER MINNESOTA WILL
ARRIVE LATE TONIGHT. WILL KEEP PARTLY TO MOSTLY CLOUDY CONDITIONS
GOING THROUGH LATE TONIGHT BEFORE MOISTURE THINS OUT.
TUESDAY...DRIER AIR WILL BE FILTERING SOUTH ACROSS MUCH OF CENTRAL
AND NORTHEAST WISCONSIN DURING THE MORNING...THOUGH LINGERING
MOISTURE OVER THE UPPER PENINSULA AND FAR NORTHERN WISCONSIN MAY
KEEP SCT-BKN STRATO-CU AROUND A LITTLE LONGER THAN FURTHER SOUTH.
NORTHERLY WINDS WILL BE DRIVING IN A COOLER AND LESS HUMID AIRMASS.
HIGH TEMPS WILL ONLY REACH FROM THE UPPER 60S TO MID 70S UNDER
MOSTLY SUNNY TO PARTLY CLOUDY SKIES.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 220 PM CDT MON JUL 22 2013
UPPER PATTERN DURING PERIOD CHARACTERIZED BY NW UPPER FLOW AND
OCNL SHORTWAVE TROFS MOVING THROUGH MEAN TROF POSITION. EACH
SHORTWAVE TROF--MID WEEK AND END OF THE WEEK--WILL BRING SCATTERED
CONVECTION AND COOLER AIR. STRONGEST OF THE SYSTEMS NEXT WEEKEND
WILL BRING CHILLY AIR INTO STATE ON SATURDAY. WHILE UPPER FLOW IS
CYCLONIC...SURFACE ANTICYCLONE AND DRY LOW-LEVELS SHOULD MINIMIZE
THREAT FOR WIDESPREAD INSTABILITY SHOWERS.
TEMP FORECAST THROUGH THE PERIOD GENERALLY A BLEND OF PREVIOUS
FORECAST AND BEST PERFORMING 22/12Z MODELS. MIN TEMPS WED AM COULD
SLIP TO 40 F IN THE BOGS OF NORTH-CENTRAL WISC.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1237 PM CDT MON JUL 22 2013
A STRONG COLD FRONT WILL BRING A SCT TO BKN LINE OF
THUNDERSTORMS ACROSS NORTH-CENTRAL WISCONSIN MID TO LATE
AFTERNOON...AND NORTHEAST WISCONSIN EARLY TO MID EVENING. STRONG
GUSTY WINDS AND LARGE HAIL ARE POSSIBLE WITH THESE STORMS...BUT THAT
WILL BE MORE OF A THREAT OVER NORTH-CENTRAL WISCONSIN THAN FURTHER
EAST. BEHIND THE FRONT...PLENTY OF MVFR CIGS OVER NORTH DAKOTA AND
MINNESOTA...AND WILL BRING THEM INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN TONIGHT. DRIER AIR WILL EVENTUALLY ARRIVE LATE TONIGHT TO
SCOUR OUT THE MVFR CIGS...WHICH WILL LEAVE GOOD FLYING WEATHER FOR
TUESDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1232 PM CDT MON JUL 22 2013
.MESOSCALE DISCUSSION...
ISSUED AT 1120 AM CDT MON JUL 22 2013
STILL ASSESSING SEVERE WEATHER POSSIBILITIES FOR LATER TODAY.
SHORT WAVE TROUGH CONTINUES TO MOVE THROUGH ONTARIO...NORTH OF
INTERNATIONAL BORDER. ASSOCIATED TRAILING COLD FRONT EXTENDS FROM
CENTRAL MINNESOTA INTO SIOUX FALLS AREA AS OF 16Z WITH WEAKENING
STORM COMPLEX ALONG MISSOURI RIVER. MORNING STRATUS AND FOG ALSO
THINING ACROSS THE AREA.
DEEP SHEAR IS MUCH MORE FAVORABLE ACROSS NORTHERN WISCONSIN WHILE
LOWER LEVEL SHEAR IS HIGHER AS YOU MOVE FURTHER SOUTH-SOUTHWEST.
0-1KM SHEAR IS ALSO STRONGER TO THE NORTH BUT DOES EXTENDED AHEAD
AND ALONG THE APPROACHING COLD FRONT. MORNING CLOUD SHIELDS KEEPING
HEATING DOWN A BIT BUT DEW POINTS ARE CLIMBING AHEAD OF FRONT SO
EXPECT MOST UNSTABLE CAPE VALUES INTO THE 2000 J/KG RANGE BY MID
AFTERNOON.
LATEST SEVERAL HRRR MESOSCALE MODEL RUNS STILL SUGGEST DEVELOPMENT
IN 19-20Z TIME FRAME. ARW/NMM MESOSCALE MODELS ALSO HINT AT THIS BUT
SOME UNCERTAINTY ON EXTENT OF COVERAGE AREA. THERE ARE HINTS
SUPERCELLS COULD INITIALLY FORM OVER NORTHERN WISCONSIN WITH ONE
COMPLEX FORMING WHILE OTHER STORMS FORM ALONG FRONT TO THE SOUTH.
MOISTURE TRANSPORT ALSO SHIFTS EAST QUICKLY THROUGH DAY SO THINKING
WE WOULD HAVE A NARROW WINDOW OF STORM POSSIBILITIES THAT COULD EVEN
SPLIT PARTS OF THE AREA. THIS COULD OCCUR AS SOUTHERN STORMS DIVE
INTO HIGHER CAPE VALUES CLOSER AND SOUTH OF I-80.
SHEAR VALUES SUGGEST ANY TORNADO RISK REMAINS HIGHEST IN NORTH
CENTRAL WISCONSIN WITH INITIAL SUPERCELLS...SOME OF WHICH COULD
ALSO PRODUCE HAIL IF CELLS CAN MATERIALIZE CAPE AND GROW THAT
STRONG. THIS AREA WOULD LIKELY FORM A MORE LINEAR STRUCTURE BY EARLY
EVENING. OTHER STORMS THAT FORM TO THE SOUTH WILL LIKELY BE MORE
MULTI-CELLULAR IN NATURE WITH MAINLY WIND THREATS.
SO OVERALL CONFIDENCE IS MODEST BUT WITH PROGRESSIVE STORMS...TIME
WINDOW LOOKS MORE CERTAIN...FROM 19Z TO 01Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE
THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING.
LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN
MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE
OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG
THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN
NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING
SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON.
THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND
BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF
MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS
TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS
AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE
AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500
TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW
SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM
BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST
OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED
PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE
CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR
ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS.
CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS
AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE
MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN
CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800
MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO
DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS
AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE
CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON.
ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE
TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED
TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE
WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING
OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT
SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL
GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE
DAMAGING WINDS.
THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE
19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST
MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING
ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN
THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE
FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP
THIS AFTERNOON.
HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER
TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB
INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE
MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS
EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS
WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT
LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS.
OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR
WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 335 AM CDT MON JUL 22 2013
SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON
TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES.
NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS
FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE
LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND
80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY
OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND
CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG
DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL
WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL
FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK
RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF
THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION
LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW
ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE
AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF
ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE
WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE
STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY.
PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK
SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE
AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90
DURING THE DAY ON SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1232 PM CDT MON JUL 22 2013
APPROACHING COLD FRONT WILL LIKELY BRING WINDOW OF CONVECTION THAT
COULD BRING TEMPORARY MVFR CONDITIONS UNTIL PASSAGE EARLY THIS
EVENING. NORMAL VEERING WIND SHIFT EXPECTED WITH FRONT AS WELL.
QUESTIONS TO WHAT DEGREE STRATUS FIELD IN BROAD COLD AIR ADVECTION
BEHIND FRONT WILL HOLD TOGETHER AND IMPACT AVIATION TONIGHT. VERY
CELLULAR NATURE TO CLOUDS SUGGEST MORE DIURNAL BUT FEEL THERE WILL
LIKELY BE A WINDOW OF LOWER CEILINGS BEFORE IT DISSIPATES. COULD SEE
SOME REFORM LATER TUESDAY AS WELL IN COLDER AIR ALOFT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE....SHEA
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....SHEA
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1220 PM CDT MON JUL 22 2013
.UPDATE...MAIN FORECAST ISSUE WILL BE AREAL COVERAGE OF STORMS AND
SEVERE RISK WITH PASSAGE OF COLD FRONT LATE THIS AFTERNOON AND
THIS EVENING. 12Z NAM SLOWER THAN 12Z GFS WITH FRONTAL PASSAGE
THROUGH THE AREA THIS EVENING. HRRR AND WRF 4KM WITH LAPS HIGH
RESOLUTION MODELS SHOW CONVECTION ASSOCIATED WITH THE FRONT MOVING
SOUTHEAST THROUGH THE FORECAST AREA BETWEEN MAINLY 23Z TODAY AND
05Z TUESDAY.
THEY DIFFER WITH TRENDS DURING THIS TIME...WITH THE HRRR FAVORING
MORE OF THE SOUTHWEST HALF OF THE AREA...AND THE WRF 4KM WITH LAPS
FAVORING CONVECTION FROM IOWA MERGING WITH FRONTAL CONVECTION.
SOME QUESTION WITH THE AMOUNT OF AREAL COVERAGE OF STORMS...AS
UPWARD VERTICAL MOTION WITH FRONT OVER THE AREA IS MODEST COMPARED
TO THE NORTHEAST AND SOUTHWEST. STILL...ENOUGH UPWARD MOTION WITH
FRONT AND PASSING MODEST 500MB VORTICITY MAXIMUM TO BRING
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE AREA.
WILL UPDATE FORECAST TO TREND IN THIS MANNER.
MEAN LAYER CAPES OF 1500 TO 2500 J/KG WITH 20 TO 25 KNOTS OF DEEP
LAYER SHEAR WILL BRING RISK FOR LARGE HAIL AND DAMAGING WINDS.
BEST CHANCES WILL BE IN SLIGHT RISK AREA FROM SPC...MAINLY IN THE
SOUTH CENTRAL WISCONSIN COUNTIES. THIS IS WHERE THE BETTER DEEP
LAYER SHEAR WILL BE LOCATED. LOCALLY HEAVY RAINFALL IS ALSO
POSSIBLE WITH DECENT PRECIPITABLE WATER VALUES. SHOWERS AND STORMS
SHOULD DIMINISH QUICKLY AFTER FRONTAL PASSAGE.
&&
.AVIATION/18Z TAFS/...VFR CONDITIONS ARE EXPECTED THROUGH THIS
AFTERNOON ACROSS TAF SITES. DIURNAL CUMULUS CLOUDS WILL LINGER
DURING THIS TIME...AND MAY BE MVFR LEVEL AT TIMES EARLY THIS
AFTERNOON. LAKE BREEZE WILL SHIFT WINDS TO THE SOUTHEAST AT
MILWAUKEE BY 18Z MONDAY...AND KENOSHA BY 21Z MONDAY. IT MAY REACH
WAUKESHA BUT LEFT OUT OF TAF THERE DUE TO UNCERTAINTY. MADISON
SHOULD SEE LIGHT SOUTHWEST WINDS.
COLD FRONT WILL SLIDE SOUTHEAST THROUGH TAF SITES BETWEEN 01Z AND
05Z TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED WITH THE FRONT...SOME OF WHICH MAY CONTAIN LARGE HAIL AND
GUSTY WINDS. BEST SHOT WILL BE AT MADISON...LOWER CONFIDENCE AT
THE EASTERN SITES. MVFR/IFR VISIBILITIES ARE POSSIBLE WITH ANY
STORMS.
VFR CONDITIONS ARE THEN EXPECTED AFTER FRONTAL PASSAGE INTO
TUESDAY. WINDS WILL SHIFT NORTH NORTHWEST AFTER THE FRONTAL
PASSAGE...AND BECOME NORTH NORTHEAST THROUGH TUESDAY. WINDS WILL
BECOME GUSTY WITH COOLER AND DRIER AIR MOVING INTO THE REGION
DURING THIS TIME. GUSTS INTO THE 20 TO 25 KNOT RANGE ARE POSSIBLE.
&&
.MARINE...A TIGHT PRESSURE GRADIENT WILL DEVELOP LATE TONIGHT INTO
TUESDAY...AFTER THE COLD FRONTAL PASSAGE. THIS WILL RESULT IN
BREEZY NORTH TO NORTHEAST WINDS ACROSS THE NEARSHORE WATERS.
FREQUENT GUSTS TO 25 KNOTS ARE POSSIBLE LATE TONIGHT INTO TUESDAY
NIGHT. THIS SHOULD CAUSE WAVES TO BECOME HIGH...WITH ONSHORE FLOW
AT TIMES. THE WAVES MAY REMAIN HIGH INTO WEDNESDAY BEFORE
SUBSIDING WITH WEAKER WINDS. THUS...A SMALL CRAFT ADVISORY MAY BE
NEEDED FOR LATE TONIGHT INTO WEDNESDAY.
&&
.PREV DISCUSSION... /ISSUED 347 AM CDT MON JUL 22 2013/
SHORT TERM...
TODAY AND TONIGHT. FORECAST CONFIDENCE LOW TO MEDIUM.
SHORT WAVE TROUGH NEAR LAKE WINNIPEG ON WATER VAPOR LOOPS IS DRIVING
ASSOCIATED SURFACE LOW ALONG U.S./CANADIAN BORDER. THUNDERSTORM
COMPLEX MOVING INTO NW MN FROM ERN N DAKOTA ALONG TRAILING SURFACE
TROUGH IN RELATIVELY WEAK WARM AIR ADVECTION REGIME AHEAD OF THIS
WAVE...WITH SWLY 850 MB WINDS OF 15 TO 25 KTS. MOIST SLY SURFACE
FLOW AHEAD OF THIS TROUGH POOLING ALONG TROUGH WITH MID-UPPER 60 DEW
POINTS.
THERMAL RIDGE PUSHES INTO CWA THIS AFTERNOON WITH 850 TEMPS OF 16 TO
18C AND 925 MB TEMPERATURES OF 24C TO 25C...LEADING TO MID-UPPER 80S
HIGHS AND A RETURN TO MUGGY CONDITIONS.
BEST CHANCES FOR THUNDERSTORMS APPEAR TO BE ACROSS CENTRAL/NORTHERN
WISCONSIN CLOSER TO THE SHORT WAVE TROUGH. BEST HEIGHT FALLS STAY
WELL NORTH OF THE CWA THROUGH THE DAY...WITH SOME WEAK FALLS DIPPING
INTO SRN WI BETWEEN 06Z AND 12Z TUESDAY AS TROUGH DEEPENS OVER
EASTERN ONTARIO.
00Z GFS AND ECMWF SHOW HIGHER MID-LEVEL RH AND BETTER OMEGA AS WELL
AS 850 MB TEMP ADVECTION STAY NORTH OF CWA. HI-RES MODELS SHOW
CONVECTION DEVELOPING ALONG FRONT TO THE NW OF FORECAST AREA DURING
PEAK MID-AFTERNOON HEATING. DECENT INSTABILITY OVER ALL OF THE AREA
THIS AFTERNOON AND EVENING...WITH SHOWALTER INDICES BETWEEN -2 AND
-3C AND SURFACE-BASED CAPE BETWEEN 1500 AND 2000 J/KG BUT BETTER
0-6KM BULK SHEAR IS TO THE NORTH...JUST BRUSHING NWRN CWA WHERE SPC
HAS DAY 1 SLIGHT RISK OF SEVERE WITH MAIN THREATS HAIL AND DAMAGING
WIND GUSTS. AFTER DRYING OUT A BIT BEHIND YESTERDAY CONVECTION...PWS
INCREASE TO 1.5 TO 1.6 INCH...SO POTENTIAL IS CERTAINLY THERE FOR
MORE HEAVY RAIN WITH STORMS.
WILL TIME PRECIPITATION CHANCES IN WITH MOISTURE CONVERGENCE AND
FRONTOGENETIC FORCING AHEAD OF THE FRONT...COVERING THE NW 1/2 OF
CWA BY 00Z...AND THE REMAINDER OF THE FORECAST AREA IN THE EARLY
EVENING. WILL LIMIT LIKELY POPS TO THE NORTH FOR NOW.
NAM SLOWER THAN GFS OR ECMWF WITH 850 MB TROUGH AXIS...WITH COOLER
AIR JUST MOVING INTO NW CWA BY 12Z TUESDAY WHILE OTHERS HAVE 850 MB
BAROCLINIC ZONE DOWN TO THE WI/IL BORDER BY 12Z. WILL KEEP CHANCE/
SLIGHT CHANCE POPS GOING AFTER 06Z...BUT CLEAR THE NW 1/2 BY 11Z
TUESDAY.
TUESDAY...FORECAST CONFIDENCE MEDIUM.
ANY LINGERING THUNDERSTORMS ALONG THE FRONT SHOULD BE OUT OF
SOUTHEAST WI BY 12Z TUE MORNING. DEBATED WHETHER OR NOT TO CARRY ANY
POPS INTO 12-15Z TUE...BUT DECIDED NOT TO BASED ON MODELS NOW
SHOWING A SLIGHTLY FASTER FRONT.
EXPECTING NORTH WINDS TO INCREASE ALONG AND BEHIND THIS COLD FRONT
TUESDAY MORNING. HIGHEST WINDS WILL BE NEAR THE LAKE. GUSTS TO 20
MPH WILL BE LIKELY.
SKIES ARE EXPECTED TO CLEAR BY TUESDAY AFTERNOON AND SUNSHINE WILL
HELP TEMPS TO REBOUND INTO THE UPPER 70S INLAND...AND LOWER/MID 70S
NEAR THE SHORELINE.
CLEAR SKIES AND RADIATIONAL COOLING WILL LEAD TO LOWS IN THE 50S.
NOT EXPECTING FOG SINCE WINDS JUST ABOVE THE GROUND WILL STILL BE IN
THE 15-20 KT RANGE.
WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE HIGH.
SURFACE HIGH PRESSURE WILL SETTLE INTO THE GREAT LAKES REGION WITH
WEAK MID AND UPPER LEVEL RIDGING MOVING INTO THE CENTER OF THE
COUNTRY. TEMPS WILL BE A LITTLE BELOW NORMAL...WITH HIGHS EXPECTED
IN THE UPPER 70S.
MODELS ARE MAINTAINING A SMALL THUNDERSTORM CHANCE FOR THU AFTERNOON
AND NIGHT...BUT THESE SEEM MINIMAL GIVEN THE DRY AIR IN PLACE OVER
SOUTHERN WI AT THIS TIME AND THE VERY WEAK FORCING ASSOCIATED WITH
THE MODEL QPF.
LONG TERM...
FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM TO LOW.
A CLOSED UPPER LOW WILL BE SPINNING OVER ONTARIO OVER THE WEEKEND. A
LOBE OF VORTICITY WILL ROTATE DOWN THROUGH WI AT SOME POINT AND
BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO SOUTHERN WI. TIMING
IS UNCERTAIN...BUT SOMETIME IN THE SATURDAY AFTERNOON/NIGHT TIME
PERIOD LOOKS REASONABLE.
UNFORTUNATELY...THERE IS A SMALL CHANCE FOR THUNDER IN EVERY TIME
PERIOD IN THE FORECAST FOR THE WEEKEND GIVEN SUBTLE MODEL
DIFFERENCES AND VERY WEAK SHORTWAVES ROTATING AROUND THE UPPER LOW
THAT COULD SPAWN AN ISOLATED THUNDERSTORM WITH DIURNAL HEATING.
CHANCES ARE VERY LOW OUTSIDE OF THE SAT AFTERNOON/NIGHT TIME.
TEMPS WILL GENERALLY BE IN THE 70S THROUGH THE WEEKEND.
AVIATION/12Z TAFS/...IFR CIGS/VSBYS HAVE MOVED INTO EASTERN TAF
SITES AS LIGHT NORTH TO NORTHEAST WINDS HAVE BROUGHT COOLER AIR OFF
THE LAKE INTO THE RAIN-MOISTENED AIR MASS OVER THE REGION. EXPECT
THE CIGS AND VSBYS TO LIFT BY MID-MORNING AS GRADIENT WINDS COME
AROUND TO THE SOUTH...THEN SOUTHWEST AHEAD OF APPROACHING COLD
FRONT. VFR THROUGH THE REST OF THE PERIOD...WITH MVFR IN SCATTERED
THUNDERSTORMS AROUND/AFTER 00Z AHEAD OF COLD FRONT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...REM
TUESDAY THROUGH SUNDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1120 AM CDT MON JUL 22 2013
.MESOSCALE DISCUSSION...
ISSUED AT 1120 AM CDT MON JUL 22 2013
STILL ASSESSING SEVERE WEATHER POSSIBILITIES FOR LATER TODAY.
SHORT WAVE TROUGH CONTINUES TO MOVE THROUGH ONTARIO...NORTH OF
INTERNATIONAL BORDER. ASSOCIATED TRAILING COLD FRONT EXTENDS FROM
CENTRAL MINNESOTA INTO SIOUX FALLS AREA AS OF 16Z WITH WEAKENING
STORM COMPLEX ALONG MISSOURI RIVER. MORNING STRATUS AND FOG ALSO
THINING ACROSS THE AREA.
DEEP SHEAR IS MUCH MORE FAVORABLE ACROSS NORTHERN WISCONSIN WHILE
LOWER LEVEL SHEAR IS HIGHER AS YOU MOVE FURTHER SOUTH-SOUTHWEST.
0-1KM SHEAR IS ALSO STRONGER TO THE NORTH BUT DOES EXTENDED AHEAD
AND ALONG THE APPROACHING COLD FRONT. MORNING CLOUD SHIELDS KEEPING
HEATING DOWN A BIT BUT DEW POINTS ARE CLIMBING AHEAD OF FRONT SO
EXPECT MOST UNSTABLE CAPE VALUES INTO THE 2000 J/KG RANGE BY MID
AFTERNOON.
LATEST SEVERAL HRRR MESOSCALE MODEL RUNS STILL SUGGEST DEVELOPMENT
IN 19-20Z TIME FRAME. ARW/NMM MESOSCALE MODELS ALSO HINT AT THIS BUT
SOME UNCERTAINTY ON EXTENT OF COVERAGE AREA. THERE ARE HINTS
SUPERCELLS COULD INITIALLY FORM OVER NORTHERN WISCONSIN WITH ONE
COMPLEX FORMING WHILE OTHER STORMS FORM ALONG FRONT TO THE SOUTH.
MOISTURE TRANSPORT ALSO SHIFTS EAST QUICKLY THROUGH DAY SO THINKING
WE WOULD HAVE A NARROW WINDOW OF STORM POSSIBILITIES THAT COULD EVEN
SPLIT PARTS OF THE AREA. THIS COULD OCCUR AS SOUTHERN STORMS DIVE
INTO HIGHER CAPE VALUES CLOSER AND SOUTH OF I-80.
SHEAR VALUES SUGGEST ANY TORNADO RISK REMAINS HIGHEST IN NORTH
CENTRAL WISCONSIN WITH INITIAL SUPERCELLS...SOME OF WHICH COULD
ALSO PRODUCE HAIL IF CELLS CAN MATERIALIZE CAPE AND GROW THAT
STRONG. THIS AREA WOULD LIKELY FORM A MORE LINEAR STRUCTURE BY EARLY
EVENING. OTHER STORMS THAT FORM TO THE SOUTH WILL LIKELY BE MORE
MULTI-CELLULAR IN NATURE WITH MAINLY WIND THREATS.
SO OVERALL CONFIDENCE IS MODEST BUT WITH PROGRESSIVE STORMS...TIME
WINDOW LOOKS MORE CERTAIN...FROM 19Z TO 01Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CDT MON JUL 22 2013
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE
THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING.
LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN
MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE
OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG
THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN
NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING
SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON.
THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND
BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF
MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS
TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS
AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE
AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500
TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW
SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM
BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST
OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED
PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE
CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR
ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS.
CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS
AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE
MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN
CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800
MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO
DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS
AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE
CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON.
ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE
TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED
TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE
WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING
OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT
SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL
GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE
DAMAGING WINDS.
THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE
19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST
MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING
ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN
THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE
FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP
THIS AFTERNOON.
HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER
TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB
INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE
MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS
EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS
WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT
LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS.
OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR
WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 335 AM CDT MON JUL 22 2013
SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON
TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES.
NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS
FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE
LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND
80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY
OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND
CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG
DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL
WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL
FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK
RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF
THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION
LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW
ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE
AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF
ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE
WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE
STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY.
PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK
SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE
AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90
DURING THE DAY ON SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 623 AM CDT MON JUL 22 2013
SOUTHERLY FLOW AHEAD OF A COLD FRONT IN WESTERN MINNESOTA HAS BEEN
BRINGING UP MORE MOISTURE INTO THE REGION AND TAF SITES. THIS
MOISTURE HAS MANIFESTED ITSELF AS LIFR TO IFR STRATUS...WITH EVEN
SOME FOG RANGING FROM VLIFR TO IFR AT RST. CEILINGS AND
VISIBILITIES WILL GRADUALLY RISE THROUGH MORNING DUE TO DAYTIME
MIXING...WITH BOTH TAF SITES LIKELY VFR BY 16Z.
DURING THE AFTERNOON...THE COLD FRONT IS EXPECTED TO MOVE THROUGH
THE TAF SITES. THUNDERSTORMS LOOK LIKELY TO ACCOMPANY THE
FRONT...SO IT IS JUST A MATTER OF TIMING. BASED ON A CONSENSUS OF
HIGH RESOLUTION MODEL FORECASTS...SPED UP THE TIMING FROM THE 06Z
TAFS...IMPACTING RST BETWEEN 19-22Z AND LSE BETWEEN 20-23Z. ITS
POSSIBLE THE STORMS COULD EXIT THE TAF SITES A LITTLE SOONER.
VISIBILITIES AND CEILING MAY FALL TO MVFR OR PERHAPS EVEN LOWER
BRIEFLY. ADDITIONALLY...POTENTIAL EXISTS FOR THE STORMS TO BRING
STRONG TO DAMAGING WIND GUSTS AND LARGE HAIL. CONFIDENCE IS TOO
LOW TO MENTION ANY SEVERE POTENTIAL DIRECTLY IN THE TAFS AT THIS
TIME. VFR CONDITIONS WITH WINDS SHIFTING TO THE NORTHWEST ARE
EXPECTED BEHIND THE FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE....SHEA
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....AJ