Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/29/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
955 PM MDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 951 PM MDT FRI JUN 28 2013
UPDATED GRIDS...MAINLY POPS...TO ACCOUNT FOR TRAINING
THUNDERSTORMS MOVING SOUTH ALONG THE I-25 CORRIDOR. -PJC
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 256 PM MDT FRI JUN 28 2013
...MORE STORMS FOR THE PLAINS LATER TODAY...
THE TWO MAIN CONCERNS THIS AFTERNOON/TONIGHT AND TOMORROW ARE THE
CHANCES OF SEVERE THUNDERSTORMS ACROSS THE I-25 CORRIDOR AND EASTERN
PLAINS...AND HEAVY PRECIPITATION IN AND AROUND BURN AREAS.
CURRENTLY...A SMALL CIRCULATION 20 TO 30 MILES NNW OF COS...WITH ASSOCIATED
QUASISTATIONARY BOUNDARY...IS HELPING TO ENHANCE THUNDERSTORM
DEVELOPMENT ALONG THE HIGHER TERRAIN. ESPECIALLY IN TELLER COUNTY
WHERE NUMEROUS CG STRIKES HAVE BEEN DETECTED WITH A STRONG CELL
CURRENTLY MOVING SOUTHWARD TOWARDS CANON CITY. THE 12Z GFS40 PV15
ALSO SHOWS A WEAK MIDLEVEL DISTURBANCE COMING THROUGH THE
NORTHWEST FLOW AROUND 00Z TONIGHT. THESE INGREDIENTS...ALONG WITH
DEWPOINTS IN THE 30`S AND 40`S ALONG THE I-25 CORRIDOR...WILL AID
IN KEEPING THUNDERSTORMS GOING AFTER SUNSET. SOME OF THESE STORMS
COULD BRIEFLY BECOME SEVERE...MINALY DUE TO GUSTY OUTFLOW WINDS.
LATER TONIGHT...THE HRRR/RAP/NAM12 CONTINUE TO INDICATE
THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS THE PLAINS THROUGH 06Z. THE
MODELS...ESPECIALLY THE HRRR AND RAP...SEEM A BIT OVERDONE ON THE
MOISTURE (CURRENT TD IN LHX IS 26)...BUT STILL FEEL ISOLATED
THUNDERSTORMS WILL BE POSSIBLE ACROSS THE PLAINS TONIGHT.
THE PRIMARY THREAT FROM THESE STORMS WILL LIKELY BE WIND...BUT IF
MOISTURE DOES RETURN VIA A NORTHEASTERLY SURGE AS THE RAP AND HRRR
FORECAST...SOME SMALL HAIL IS POSSIBLE AS 0-6KM BULK SHEAR IS
30-40KTS ACROSS THE PLAINS.
THE NAM12/GFS/EC ALL SHOW ANOTHER...MORE SIGNIFICANT...DISTURBANCE
IN THE NORTHWEST FLOW PUSHING THROUGH THE AREA SATURDAY MORNING.
THIS DISTURBANCE WILL DROP A COLD FRONT THROUGH THE AREA AROUND 12Z
SATURDAY. THIS WILL CREATE GUSTY NORTHEASTERLY WINDS AND HELP DROP
700MB TEMPERATURES TO AROUND 11C...LEADING TO COOLER MAX
TEMPERATURES AND INCREASED MOSITURE ACROSS THE FORECAST AREA.
THUNDERSTORMS ARE LIKELY ONCE AGAIN ACROSS THE MOUNTAINS DURING
THE LATE MORNING AND AFTERNOON. CURRENT ACTIVE BURN AREAS SUCH AS
THE WEST FORK COMPLEX AND EAST PEAK FIRES...ALONG WITH THE WALDO
CANYON SCAR...WILL NEED TO MONITORED FOR FLOODING POTENTIAL
TOMORROW AFTERNOON. THE POTENTIAL WILL EXIST ONCE AGAIN FOR
ISOLATED SEVERE STORMS ACROSS THE EASTERN PLAINS DUE TO THE
INCREASE IS MOISTURE. -PJC
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 256 PM MDT FRI JUN 28 2013
...COOLER TEMPERATURES WITH CONTINUED CHANCES OF RAIN...AND FLASH
FLOODING CONCERNS FOR THE BURN SCARS...
AN ACTIVE PERIOD IS EXPECTED AS THE UPPER LEVEL RIDGE AXIS SHIFTS
WEST AND REMAINS CENTERED THROUGH THE GREAT BASIN. NORTHERLY FLOW
ALOFT IS EXPECTED ACROSS COLORADO THROUGH AT LEAST TUESDAY. AT THE
SURFACE...EXPECT EAST TO SOUTHEAST UPSLOPE SURFACE FLOW TO
CONTINUE WITH DEWPOINTS IN THE 50S ACROSS THE PLAINS SUNDAY.
MODELS SHOW A WEAK DISTURBANCE MOVING THROUGH THE FLOW ALOFT
SUNDAY AND CURRENT MODEL TIMING SHOWS IT MOVING THROUGH SOUTHEAST
COLORADO DURING PEAK HEATING. WITH COOLER AIRMASS IN PLACE...CAPES
IN THE 1000-1500J/KG RANGE ALONG THE SOUTHEAST COLORADO MOUNTAINS...
EXPECT TO HAVE ANOTHER DAY OF CONVECTION FIRING BY EARLY AFTERNOON
OVER THE HIGHER ELEVATIONS. PRIMARY CONCERN WOULD BE FOR LOCALLY
HEAVY RAINFALL TO IMPACT ONE OF THE BURN SCARS
SUNDAY...HOWEVER...WITH ENOUGH SURFACE HEATING...
INSTABILITY...AND FAVORABLE WIND SHEAR PROFILES...A FEW OF THE
STORMS COULD BECOME STRONG TO SEVERE. THIS GENERAL PATTERN
CONTINUES THROUGH TUESDAY ALTHOUGH CAPES AND DEWPOINTS DECREASE
MONDAY AND TUESDAY WHICH WILL LIMIT THE COVERAGE...INTENSITY...AND
RAINFALL POTENTIAL OF THUNDERSTORMS.
ON WEDNESDAY...A STRONG UPPER LEVEL DISTURBANCE MOVES SOUTH
THROUGH THE BACKSIDE OF THE TROF AXIS AND CLOSES OFF OVER THE HIGH
PLAINS THURSDAY. GFS FORECASTS THE CLOSED LOW TO RETROGRADE FRIDAY
TO SOUTHWESTERN SOUTH DAKOTA. THE ECMWF KEEPS THE CLOSED LOW
FARTHER SOUTH...OVER WESTERN KS AND THE OK/TX PANHANDLES. THE GFS
SCENARIO...WHICH HAS BEEN CONSISTENT FOR A FEW RUNS NOW...KEEPS
SOUTHEAST COLORADO IN A COOL AND ACTIVE PATTERN WITH THUNDERSTORM
CHANCES EACH DAY FROM WEDNESDAY THRU FRIDAY. THE ECMWF SCENARIO
KEEPS BEST PRECIPITATION CHANCES TO THE SOUTH AND EAST OF THE CWA.
STILL EXPECT THE COOLER TEMPERATURES AND INCREASED RELATIVE
HUMDITIES TO BRING SOME RELIEF TO WILDFIRE THREAT. STARK
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 256 PM MDT FRI JUN 28 2013
THUNDERSTORMS AND ASSOCIATED OUTFLOW WINDS WILL CONTINUE TO BE THE
MAIN CONCERN AT KALS...KCOS...AND KPUB TONIGHT AND SATURDAY
AFTERNOON. THE BEST CHANCE FOR THUNDERSTORMS WILL BE AT KCOS AND THE
SURROUNDING MOUNTAINS. MVFR CONDITIONS WILL BE POSSIBLE LATER THIS
AFTERNOON AND EVENING AT KCOS. VFR CONDITIONS ARE EXPECTED AT KALS
AND KPUB THROUGH SATURDAY EVENING. -PJC
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PJC
SHORT TERM...PJC
LONG TERM...STARK
AVIATION...PJC
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
221 PM EDT THU JUN 27 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND
INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE
STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW
PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA
LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO
THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK
TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE
PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT.
&&
.NEAR TERM /THROUGH TONIGHT/...
SEL7 IS POSTED. TORNADO WATCH. GOING TO TAKE QUITE SOME TIME FOR
CONVECTION TO PRESS EWD INTO COASTAL NJ PER SEA BREEZE BOUNDARY.
POCKETS OF CU FIELDS SEEN ON SATELLITE IMAGERY MIGHT YIELD A STORM
THERE THIS AFTN. OTRW WE NEED TO LOOK TO OUR SOUTHWEST.
THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED DOWN
ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I LIKE
THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS OVERALL
DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY ACCURATE.
THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA
ARRIVES LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE
EXTENDED N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF
0-6KM SHEAR NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO
PA LATE TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS
FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD)
HERE FOR THIS TIME OF YEAR.
SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM
FRIDAY OVER E PA AND NNJ. FFG IS SO HIGH IN E PA THAT NO FFA THERE.
THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N
OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED.
OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS
TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING
RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED WET MICROBURST G45KT.
TOR POSSIBLE IN STRONG CONVECTION MAINLY ALONG SFC BOUNDARY I95
NWWD. ITS A LOW PROB DUE TO SHEAR NOT BEING EXCESSIVELY STRONG BUT
LOWER LCLS AND THE BOUNDARY DO OFFER THE OPPORTUNITY.
HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED
DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING.
NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL
KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD
RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70.
OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C
NEAR 00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION
OCCURS.
WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING
BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1640Z COSPA
TRYING TO BUST OUT SCT CONVECTION DE VALLEY 21Z THEN SWEEP IT
NNEWD THRU NJ LATE THIS AFTN. MY CONFIDENCE ON THIS SOLN IS BELOW
AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION
UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING.
MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER
THAN THE LESS RESOLVED NAM/GFS.
LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR
DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW
TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING
IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE?
THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS.
LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER
ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS
PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT
OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR
ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION.
THIS MORNING HAD SOME 1/4SM DENSE FOG IN FAR NW NJ. EXPECTING A
BIT OF THAT LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 330 PM
UPDATE.
&&
.SHORT TERM /FRIDAY/...
THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY
CUT IT TO 6 AM IN THE 330 PM FCST UPDATE AS ITS DIFFICULT TO SEE
ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI.
WE`LL CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE.
DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT
STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA
AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID
30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY
AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE
HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA
AREA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND,
WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW
ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS
FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM
EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF
STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP
MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA
THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE
FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN
THE FORECAST EACH DAY.
A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO
BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD
LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT
WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP
ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS
JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL
BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP
CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A
CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF
NEXT WEEK.
WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL
BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND
1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR
STRONG THUNDERSTORMS WITH HEAVY RAIN.
WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES
REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT
EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST
TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH
LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THIS AFTERNOON...VFR SCT CLOUDS AOA 5000 FT AND A GENERAL S-SW
WIND G15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING
TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z.
TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH
MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL
EXPECTED AFTER 07Z MOST TAF LOCATIONS.
FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT-
BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER
20Z.
OUTLOOK...
FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF
MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND
MORNING LOW CLOUDS/FOG.
&&
.MARINE...
SCA IS POSTED.
WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 16Z
SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND
SHOULD CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD
ARRIVE IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE
SLOW TO SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES
SEEMINGLY FOR AT LEAST ANOTHER WEEK ON THE WATERS.
CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON
DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY
ENTRANCE.
SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME
MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT.
OUTLOOK...
THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR
A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH
MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW
ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL
HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE
SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN
PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER
ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL
FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE
INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND
THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS
AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH
FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR
NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN
EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY.
WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON
AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER
HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD
PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES.
IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE
EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY
OCCUR DURING THE HEAVIEST DOWNPOURS.
&&
.RIP CURRENTS...
AM HOLDING ONTO THE MDT RISK. ITS LOW NOW BUT BY 5 PM MAY BE UP
TO MDT AS GRADIENT SLY FLOW INCREASES.
THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW
JERSEY COAST LATE TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY
FLOW AND A BIT OF AN INCREASE IN THE SWELL PERIOD.
FOR FRIDAY...12Z WW3 IS STILL PROJECTING A 5 FT 8 SEC SSE SWELL
WITH A S WIND 15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR
NJ AND MARGINAL LOW-MDT FOR DE.
A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH
AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC
PERIOD.
&&
.CLIMATE...
WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS...
PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND
00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG
TROF IN THE NE USA DAY 9-10 .. JULY 5-6. I`D SIDE WITH GFS/NAEFS
ON THIS.
SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL
PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER
THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS
BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE
DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY
COUNTRYSIDE.
PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF
GENERALLY 1 TO 2 DEGREES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE
NORMAL AT KACY AND MAYBE 2.5 ABOVE NORMAL AT KGED.
AS OF 6/26 PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL.
THE JUNE 1981-2010 AVG IS 73.2.
JUNE RAINFALL BELOW..
KILG ALREADY RECORD MONTHLY RFALL AT 10.09
KPHL RANKED #2 AT 8.81 INCHES BEHIND THE 10.06 JUNE 1998 RECORD.
KACY RANKED #3 AT 7.20 BEHIND THE 7.57 IN 1935 AND RECORD JUNE
TOTAL OF 8.45 IN 1920.
KABE STILL RANKED 8TH WETTEST JUNE AT 6.48 INCHES. THE MONTHLY
RECORD IS 10.51 IN 1938.
OUT OF REACH DAILY RECORD RAINFALL FOR TODAY:
ILG 4.77 1938
RDG 3.33 1883
PHL 3.27 1938
ABE 2.70 1938
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR NJZ001-007-008.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT
FRIDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG 221
SHORT TERM...DRAG 221
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON 221
MARINE...DRAG/ROBERTSON 221
HYDROLOGY...
RIP CURRENTS...
CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1252 PM EDT THU JUN 27 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND
INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE
STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW
PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA
LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO
THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK
TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE
PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 14Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR
SANDY HOOK WESTWARD NEAR RTE 80 THROUGH NNJ INTO NE PA WITH SFC
LOW PRES NEAR KMRB OUT TO NRN OHIO AND LOWER MI.
THE WFRONT MAY FORCE SOME CONVECTION EARLY THIS AFTN IN NNJ.
OTRW THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED
DOWN ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I
LIKE THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS
OVERALL DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY
ACCURATE.
THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA
ARRIVES LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE
EXTENDED N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF
0-6KM SHEAR NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO
PA LATE TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS
FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD)
HERE FOR THIS TIME OF YEAR.
SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM
FRIDAY OVER E PA AND NNJ. FFG IS SO HIGH IN E PA THAT NO FFA THERE.
THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N
OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED.
OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS
TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING
RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED WET MICROBURST G45KT.
HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED
DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING.
NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL
KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD
RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70.
OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C
NEAR 00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION
OCCURS.
WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING
BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1640Z COSPA
TRYING TO BUST OUT SCT CONVECTION DE VALLEY 21Z THEN SWEEP IT
NNEWD THRU NJ LATE THIS AFTN. MY CONFIDENCE ON THIS SOLN IS BELOW
AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION
UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING.
MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER
THAN THE LESS RESOLVED NAM/GFS.
LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR
DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW
TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING
IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE?
THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS.
LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER
ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS
PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT
OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR
ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION.
THIS MORNING HAD SOME 1/4SM DENSE FOG IN FAR NW NJ. EXPECTING A
BIT OF THAT LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 330 PM
UPDATE.
&&
.SHORT TERM /FRIDAY/...
THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY
CUT IT TO 6 AM IN THE 330 PM FCST UPDATE AS ITS DIFFICULT TO SEE
ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI.
WE`LL CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE.
DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT
STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA
AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID
30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY
AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE
HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA
AREA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND,
WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW
ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS
FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM
EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF
STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP
MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA
THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE
FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN
THE FORECAST EACH DAY.
A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO
BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD
LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT
WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP
ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS
JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL
BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP
CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A
CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF
NEXT WEEK.
WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL
BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND
1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR
STRONG THUNDERSTORMS WITH HEAVY RAIN.
WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES
REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT
EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST
TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH
LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THIS AFTERNOON...VFR SCT CLOUDS AOA 5000 FT AND A GENERAL S-SW
WIND G15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING
TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z.
TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH
MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL
EXPECTED AFTER 07Z MOST TAF LOCATIONS.
FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT-
BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER
20Z.
OUTLOOK...
FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF
MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND
MORNING LOW CLOUDS/FOG.
&&
.MARINE...
SCA IS POSTED.
WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 16Z
SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND
SHOULD CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD
ARRIVE IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE
SLOW TO SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES
SEEMINGLY FOR AT LEAST ANOTHER WEEK ON THE WATERS.
CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON
DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY
ENTRANCE.
SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME
MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT.
OUTLOOK...
THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR
A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH
MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW
ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL
HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE
SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN
PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER
ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL
FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE
INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND
THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS
AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH
FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR
NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN
EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY.
WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON
AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER
HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD
PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES.
IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE
EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY
OCCUR DURING THE HEAVIEST DOWNPOURS.
&&
.RIP CURRENTS...
AM HOLDING ONTO THE MDT RISK. ITS LOW NOW BUT BY 5 PM MAY BE UP
TO MDT AS GRADIENT SLY FLOW INCREASES.
THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW
JERSEY COAST LATE TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY
FLOW AND A BIT OF AN INCREASE IN THE SWELL PERIOD.
FOR FRIDAY...12Z WW3 IS STILL PROJECTING A 5 FT 8 SEC SSE SWELL
WITH A S WIND 15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR
NJ AND MARGINAL LOW-MDT FOR DE.
A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH
AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC
PERIOD.
&&
.CLIMATE...
WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS...
PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND
00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG
TROF IN THE NE USA DAY 9-10 .. JULY 5-6. I`D SIDE WITH GFS/NAEFS
ON THIS.
SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL
PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER
THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS
BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE
DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY
COUNTRYSIDE.
PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF
GENERALLY 1 TO 2 DEGREES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE
NORMAL AT KACY AND MAYBE 2.5 ABOVE NORMAL AT KGED.
AS OF 6/26 PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL.
THE JUNE 1981-2010 AVG IS 73.2.
JUNE RAINFALL BELOW..
KILG ALREADY RECORD MONTHLY RFALL AT 10.09
KPHL RANKED #2 AT 8.81 INCHES BEHIND THE 10.06 JUNE 1998 RECORD.
KACY RANKED #3 AT 7.20 BEHIND THE 7.57 IN 1935 AND RECORD JUNE
TOTAL OF 8.45 IN 1920.
KABE STILL RANKED 8TH WETTEST JUNE AT 6.48 INCHES. THE MONTHLY
RECORD IS 10.51 IN 1938.
OUT OF REACH DAILY RECORD RAINFALL FOR TODAY:
ILG 4.77 1938
RDG 3.33 1883
PHL 3.27 1938
ABE 2.70 1938
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY
MORNING FOR NJZ001-007-008.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT
FRIDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG 1251
SHORT TERM...DRAG 1251
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON 1251
MARINE...DRAG/ROBERTSON 1251
HYDROLOGY...
RIP CURRENTS... 1251
CLIMATE...1251
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1200 PM EDT THU JUN 27 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND
INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE
STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW
PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA
LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO
THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK
TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE
PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 14Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR
SANDY HOOK WESTWARD NEAR RTE 80 THROUGH NNJ INTO NE PA.
THAT COULD SERVE AS A FOCUS FOR LATE MORNING EARLY AFTN CONVECTION.
OTRW THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED
DOWN ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I
LIKE THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS
OVERALL DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY
ACCURATE.
POPS WILL BE FURTHER ADJUSTED DOWN FOR THIS AFTN EXCEPT DEL VALLEY
WEST AND I 80 NORTH WHERE TSTMS WILL DEVELOP SOMETIME LATE TODAY
OR THIS EVENING. THERE IS STILL A SMALL CHC OF CONVECTION IN S NJ/DE
AROUND 18Z NEAR ANY CONVERGENCE ZONE BUT THE REAL DEAL ACTION WILL
BE LATE IN THE DAY IN E PA/E/MD.
THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES
LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED
N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR
NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE
TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS FLUXES
INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD) HERE FOR
THIS TIME OF YEAR.
SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM
FRIDAY OVER NE PA AND NNJ. FFG IS SO HIGH IN NE PA THAT NO FFA THERE.
THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N
OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED.
OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS
TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING
RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED G40-45KT.
HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED
DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING.
NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL
KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD
RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70.
930 AM UPDATE RAISED HOURLY TEMPS BY 2F AND WILL RAISE MAX A DEG
OR 2 BY 1130AM. 12Z/27 ABERDEEN MD SOUNDING HAS A PWAT OF 1.71 KI
29 AND TT 43..SWEAT 177. MAX TT 88. MAX WIND LOWEST 20000 FT IS 25
KT.
12Z IAD SOUNDING ALSO A MAX T OF 88F WITH A KI 26 AND PWAT 1.57.
MORE SWLY FLOW IN THAT SOUNDING AND A BIT MORE WIND.
OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR
00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS.
WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING
BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1415Z COSPA
TRYING TO BUST OUT SCT CONVECTION DE BAY AROUND 19Z THEN SWEEP IT
NNEWD THRU NJ THIS AFTN. MY CONFIDENCE ON THIS DE BAY NJ SOLN IS
BELOW AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION
UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING.
MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER
THAN THE LESS RESOLVED NAM/GFS.
LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR
DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW
TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING
IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE?
THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS.
LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER
ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS
PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT
OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR
ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION.
THIS MORNING HAD SOME 1/4SM IN FAR NW NJ. EXPECTING A BIT OF THAT
LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 930 AM UPDATE.
&&
.SHORT TERM /FRIDAY/...
THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY
CUT IT TO 6 AM IN THE 1230 PM FCST UPDATE AS ITS DIFFICULT TO SEE
ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL
CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE.
DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT
STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA
AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID
30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY
AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE
HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA
AREA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND,
WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW
ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS
FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM
EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF
STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP
MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA
THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE
FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN
THE FORECAST EACH DAY.
A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO
BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD
LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT
WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP
ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS
JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL
BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP
CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A
CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF
NEXT WEEK.
WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL
BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND
1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR
STRONG THUNDERSTORMS WITH HEAVY RAIN.
WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES
REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT
EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST
TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH
LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR SCT CLOUDS AOA 5000 FT (FEW 2000 FT AT 14Z SHOULD
LIFT REFORM AOA 5000 BY 18Z) AND A GENERAL S-SW WIND G15 KT. IFR
CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING TSTMS EXPECTED
AFTER 20Z IN E PA REACHING NJ AROUND 00Z.
TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH
MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL
EXPECTED AFTER 07Z MOST TAF LOCATIONS.
FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT-
BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER
20Z.
OUTLOOK...
FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF
MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND
MORNING LOW CLOUDS/FOG.
&&
.MARINE...
SCA IS POSTED.
WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 14Z
SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD
CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE
IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO
SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY
FOR AT LEAST ANOTHER WEEK ON THE WATERS.
CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON
DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY
ENTRANCE.
SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME
MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT.
OUTLOOK...
THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR
A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH
MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW
ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL
HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE
SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN
PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER
ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL
FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE
INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND
THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS
AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH
FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR
NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN
EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY.
WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON
AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER
HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD
PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES.
IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE
EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY
OCCUR DURING THE HEAVIEST DOWNPOURS.
&&
.RIP CURRENTS...
THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW
JERSEY COAST TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW
AND A BIT OF AN INCREASE IN THE SWELL PERIOD. IF THE SWELL IS ONLY
3 FT 6 SEC AT 18Z...AND THE WIND S 15KT WE WILL LOWER THE RISK TO
LOW AND UPDATE THE SRF.
AS IT STANDS WE ARE PROJECTING AT WORST A 4 FT 6 SEC SSE SWELL AT
18Z AND A S WIND 15 KT. EVEN THAT GIVES US A LOW RISK ON THE CUSP OF
MDT. THE ONLY REASON AM NOT TAKING ACTION NOW IS THAT THE 14Z SLY
WIND AT 44009 IS GUSTING 19KT. I`LL CHECK THIS AT 1545Z AND MAY
DOWN GRADE THE RISK AT 16Z.
NO MATTER...THERE IS RISK OF SIGNIFICANT RIP CURRENT FORMATION
THIS AFTERNOON.
FOR FRIDAY...WW3 IS PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND
15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL
LOW-MDT FOR DE.
A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH
AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC
PERIOD.
&&
.CLIMATE...
WE`LL ADD MONTHLY CLI INFORMATION LATER TODAY AS TIME AVAILS.
WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS...
PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND
00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG
TROF IN THE NE USA DAY 9-10 .. JULY 5-6
SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL
PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER
THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS
BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE
DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY
COUNTRYSIDE.
PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF
1GENERALLY TO 2 DEGREES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE
NORMAL AT KACY.
AS OF 6/26 PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL.
THE JUNE 1981-2010 AVG IS 73.2.
JUNE RAINFALL BELOW..
KILG ALREADY RECORD MONTHLY RFALL AT 10.09
KPHL RANKED #2 AT 8.81 INCHES BEHIND THE 10.06 JUNE 1998 RECORD.
KACY RANKED #3 AT 7.20 BEHIND THE 7.57 IN 1935 AND RECORD JUNE
TOTAL OF 8.45 IN 1920.
KABE STILL RANKED 8TH WETTEST JUNE AT 6.48 INCHES. THE MONTHLY
RECORD IS 10.51 IN 1938.
WE MAY ADD DAILY RECORD RFALL TO THIS SECTION AT 330 PM FOR
TODAY... FOR KRDG...KABE...KPHL...KILG.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY
MORNING FOR NJZ001-007-008.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT
FRIDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG
SHORT TERM...DRAG
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON
MARINE...DRAG/ROBERTSON
HYDROLOGY...
RIP CURRENTS...
CLIMATE...1158A
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1030 AM EDT THU JUN 27 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND
INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE
STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW
PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA
LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO
THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK
TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE
PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 14Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR
SANDY HOOK WESTWARD NEAR RTE 80 THROUGH NNJ INTO NE PA.
THAT COULD SERVE AS A FOCUS FOR LATE MORNING EARLY AFTN CONVECTION.
OTRW THE 12Z NAM...ONE OF THE GLOBAL MODELS...HAS FINALLY CALMED
DOWN ABOUT GENERATING TSTMS PRIOR TO 18Z OVER MOST OF THE AREA. I
LIKE THIS VERSION OF THE NAM THROUGH 12Z FRIDAY AND THINK ITS
OVERALL DEPICTION OF HEAVY QPF IS TEMPORALLY AND SPATIALLY
ACCURATE.
POPS WILL BE FURTHER ADJUSTED DOWN FOR THIS AFTN EXCEPT DEL VALLEY
WEST AND I 80 NORTH WHERE TSTMS WILL DEVELOP SOMETIME LATE TODAY
OR THIS EVENING. THERE IS STILL A SMALL CHC OF CONVECTION IN S NJ/DE
AROUND 18Z NEAR ANY CONVERGENCE ZONE BUT THE REAL DEAL ACTION WILL
BE LATE IN THE DAY IN E PA/E/MD.
THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES
LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED
N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR
NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE
TODAY IS FOR ME A STRONG SIGNAL FOR SIGNIFICANT SVR...AS FLUXES
INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD) HERE FOR
THIS TIME OF YEAR.
SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM
FRIDAY OVER NE PA AND NNJ. FFG IS SO HIGH IN NE PA THAT NO FFA THERE.
THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N
OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED.
OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS
TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING
RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED G40-45KT.
HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED
DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING.
NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL
KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD
RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70.
930 AM UPDATE RAISED HOURLY TEMPS BY 2F AND WILL RAISE MAX A DEG
OR 2 BY 1130AM. 12Z/27 ABERDEEN MD SOUNDING HAS A PWAT OF 1.71 KI
29 AND TT 43..SWEAT 177. MAX TT 88. MAX WIND LOWEST 20000 FT IS 25
KT.
12Z IAD SOUNDING ALSO A MAX T OF 88F WITH A KI 26 AND PWAT 1.57.
MORE SWLY FLOW IN THAT SOUNDING AND A BIT MORE WIND.
OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR
00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS.
WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING
BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS. 1415Z COSPA
TRYING TO BUST OUT SCT CONVECTION DE BAY AROUND 19Z THEN SWEEP IT
NNEWD THRU NJ THIS AFTN. MY CONFIDENCE ON THIS DE BAY NJ SOLN IS
BELOW AVG AND CAN EASILY SEE IT TOO DRY ALOFT TO SUPPORT CONVECTION
UNTIL THE PRIMARY SHORT WAVE ARRIVES THIS EVENING.
MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER
THAN THE LESS RESOLVED NAM/GFS.
LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR
DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW
TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING
IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE?
THERE MAY ALSO BE A BAND OF SHOWERS AT 10Z FRI OVER THE POCONOS.
LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER
ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS
PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT
OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR
ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION.
THIS MORNING HAD SOME 1/4SM IN FAR NW NJ. EXPECTING A BIT OF THAT
LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 930 AM UPDATE.
&&
.SHORT TERM /FRIDAY/...
THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY
CUT IT TO 6 AM IN THE 1230 PM FCST UPDATE AS ITS DIFFICULT TO SEE
ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL
CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE.
DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT
STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA
AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID
30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY
AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE
HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA
AREA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND,
WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW
ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS
FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM
EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF
STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP
MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA
THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE
FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN
THE FORECAST EACH DAY.
A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO
BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD
LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT
WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP
ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS
JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL
BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP
CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A
CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF
NEXT WEEK.
WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL
BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND
1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR
STRONG THUNDERSTORMS WITH HEAVY RAIN.
WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES
REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT
EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST
TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH
LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR SCT CLOUDS AOA 5000 FT (FEW 2000 FT AT 14Z SHOULD
LIFT REFORM AOA 5000 BY 18Z) AND A GENERAL S-SW WIND G15 KT. IFR
CONDS IN SW G30-40KT IN TORRENTIAL RAIN PRODUCING TSTMS EXPECTED
AFTER 20Z IN E PA REACHING NJ AROUND 00Z.
TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH
MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL
EXPECTED AFTER 07Z MOST TAF LOCATIONS.
FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT-
BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER
20Z.
OUTLOOK...
FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF
MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND
MORNING LOW CLOUDS/FOG.
&&
.MARINE...
SCA IS POSTED.
WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 14Z
SWELL IS 1-2 FT 6-7 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD
CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE
IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO
SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY
FOR AT LEAST ANOTHER WEEK ON THE WATERS.
CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON
DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY
ENTRANCE.
SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME
MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT.
OUTLOOK...
THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR
A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH
MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW
ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL
HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE
SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN
PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER
ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL
FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE
INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND
THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS
AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH
FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR
NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN
EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY.
WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON
AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER
HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD
PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES.
IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE
EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY
OCCUR DURING THE HEAVIEST DOWNPOURS.
&&
.RIP CURRENTS...
THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW
JERSEY COAST TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW
AND A BIT OF AN INCREASE IN THE SWELL PERIOD. IF THE SWELL IS ONLY
3 FT 6 SEC AT 18Z...AND THE WIND S 15KT WE WILL LOWER THE RISK TO
LOW AND UPDATE THE SRF.
AS IT STANDS WE ARE PROJECTING AT WORST A 4 FT 6 SEC SSE SWELL AT
18Z AND A S WIND 15 KT. EVEN THAT GIVES US A LOW RISK ON THE CUSP OF
MDT. THE ONLY REASON AM NOT TAKING ACTION NOW IS THAT THE 14Z SLY
WIND AT 44009 IS GUSTING 19KT. I`LL CHECK THIS AT 1545Z AND MAY
DOWN GRADE THE RISK AT 16Z.
NO MATTER...THERE IS RISK OF SIGNIFICANT RIP CURRENT FORMATION
THIS AFTERNOON.
FOR FRIDAY...WW3 IS PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND
15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL
LOW-MDT FOR DE.
A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH
AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC
PERIOD.
&&
.CLIMATE...
WE`LL ADD MONTHLY CLI INFORMATION LATER TODAY AS TIME AVAILS.
WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW PREVAILS...
PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS AND
00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG
TROF IN THE NE USA DAY 9-10 .. JULY 5-6
SINCE THE WARMER THAN NORMAL AND HUMID WEATHER PATTERN WILL
PROBABLY CONTINUE FOR THE NEXT WEEK OR TWO. MOST OF THE WARMER
THAN NORMAL DEPARTURES WILL BE ASSOCIATED WITH NIGHTTIME LOWS
BEING SIGNIFICANTLY ON THE WARM SIDE OF NORMAL....POSITIVE
DEPARTURES OF 5 TO 10 DEGREES ON MANY NIGHTS...ESPECIALLY
COUNTRYSIDE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY
MORNING FOR NJZ001-007-008.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT
FRIDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG 1030
SHORT TERM...DRAG 1030
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON 1030
MARINE...DRAG/ROBERTSON 1030
HYDROLOGY...
RIP CURRENTS...1030
CLIMATE...1030
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
911 AM EDT THU JUN 27 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND
INTO CENTRAL PENNSYLVANIA LATER TODAY AND INTO TONIGHT, BEFORE
STRENGTHENING AND MOVING INTO THE NORTHEAST ON FRIDAY. THIS LOW
PRESSURE SYSTEM WILL BRING A SLOW MOVING COLD FRONT INTO THE AREA
LATER TONIGHT THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO
THE WEEKEND. A BERMUDA HIGH PRESSURE SYSTEM MAY TRY TO BUILD BACK
TOWARD THE EAST COAST NEXT WEEK, WHICH MAY EITHER PUSH THE
PREVIOUS FRONT WESTWARD OR HELP WASH IT OUT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 12Z A WEAK FRONTAL BOUNDARY IS DRAPED ACROSS NORTHERN NJ...NEAR
SANDY HOOK WESTWARD TO PROBABLY NEAR RTE 80 IN NE PA.
THAT COULD SERVE AS A FOCUS FOR LATE MORNING EARLY AFTN CONVECTION.
THE NEG TILT SHORT WAVE WITH ASSTD SFC LOW DEEPENING INTO PA ARRIVES
LATE THIS AFTN AND EVENING...RUNNING INTO 1200J ML CAPE EXTENDED
N-S FROM THE HUD VALLEY THRU NJ-DELMARVA AND 30KT OF 0-6KM SHEAR
NE PA AND NNJ. THE INTENSIFICATION OF THE SFC LOW INTO PA LATE
TODAY IS FOR ME A SIGNAL FOR SVR...POTENTIAL BIG SVR EVENING AS
FLUXES INCREASE AND INTENSITY OF THE SFC LOW IS ANOMALOUS (-2SD)
HERE FOR THIS TIME OF YEAR.
SVR AND FF POTENTIAL IF CONVECTION OCCURS BETWEEN 4 PM AND 2 AM
FRIDAY OVER NE PA AND NNJ. FFG IS SO HIGH IN NE PA THAT NO FFA THERE.
THERE IS ISOLATED TORNADO POTENTIAL...ESPECIALLY IMO..NEAR AND N
OF RTE 80 WHERE BETTER 0-3KM SHEAR IS EXPECTED.
OTRW...FURTHER S IN WEAKLY DIFFLUENT FLOW...03Z/27 SREF PWAT BUILDS
TO 2 INCHES BY 00Z/28 IN SE PA...DELMARVA AND SNJ AND GULLY WASHING
RAINS ARE POSSIBLE WITH LOCAL FF AND OR ISOLATED G40-45KT.
HOT TODAY PRIOR TO THE ONSET OF HEAVY CONVECTION WHICH IS DELAYED
DUE TO A WEDGE OF DRY AIR ALOFT PASSING THROUGH OUR AREA THIS MORNING.
NEAR 90F IN PHL AND POTENTIAL TO EXTEND HEATWAVE TO 4 DAYS AT KPHL
KILG KACY AND KGED...THO SLY FLOW MAY PRECLUDE. STILL HI SHOULD
RISE INTO THE MID 90S WITH DEWPOINTS NEAR 70.
THE 930 AM UPDATE WILL RAISE TEMPS AND DEWS TODAY BY 2F. 12Z/27
ABERDEEN MD SOUNDING HAS A PWAT OF 1.71 KI 29 AND TT 43..SWEAT
177. MAX TT 88. MAX WIND LOWEST 20000 FT IS 25 KT.
12Z IAD SOUNDING ALSO A MAX T OF 88F WITH A KI 26 AND PWAT 1.57.
MORE SWLY FLOW IN THAT SOUNDING AND A BIT MORE WIND.
OVERALL: KI LESS THAN 30C THROUGH 18Z BUT INCREASES TO 36-38C NEAR
00Z IN AN ARC SEWD THRU E PA AND DELMARVA WHEN CONVECTION OCCURS.
WE`LL FOLLOW A BLEND OF CONSTANTLY UPDATING COSPA AND HOURLY UPDATING
BLENDED RAP MODEL STABLE AND CONVECTIVE OUTBREAKS.
MY OWN VIEW ON YDYS MODEL PERFORMANCE...THE COSPA AND RAP WAS BETTER
THAN THE LESS RESOLVED NAM/GFS.
LATE TONIGHT...AFTER 04Z... THE HEAVY CONVECTION WILL BE ENDING OR
DIMINISHING IN DELMARVA AND SE PA AND PROGRESSIVELY ENDING FM SW
TO NE OVERNIGHT SO THAT BY 10Z...NO CONVECTION SHOULD BE OCCURRING
IN OUR CWA EXPECT POSSIBLY A TAIL FM SNE-LI DOWN INTO SE DE?
LOW CLOUDS AND/OR FOG SHOULD BE MORE WIDESPREAD LATE TONIGHT...AFTER
ROUGHLY 07Z AS 03Z/27 SREF HAS HIGHER PROBS OF IFR CONDS AND TSECS
PLAN VIEW OF THE LOWEST 50 MB SHOWS MUCH MORE MOISTURE THAN THAT
OF THIS MORNING WITH MOSTLY CLEAR SKIES ABOVE THE BL AS DRY AIR
ALOFT SWEEPS NEWD CHASING OUT THE HIGH KI AND ASSTD CONVECTION.
THIS MORNING HAD SOME 1/4SM IN FAR NW NJ. EXPECTING A BIT OF THAT
LATE TONIGHT AND WILL ADD FOG TO THE FCST IN THE 930 AM UPDATE.
&&
.SHORT TERM /FRIDAY/...
THE FLASH FLOOD WATCH ENDING TIME WAS KEPT AT 11 AM FRIDAY BUT MAY
CUT IT TO 6 AM IN THE 1230 PM FCST UPDATE AS ITS DIFFICULT TO SEE
ANY FF CAUSING TSTMS IN THE FFA AREA OF OUR CWA AFTER 6 AM FRI. WE`LL
CHECK LATER FCST GUIDANCE TO CONFIRM THIS POTENTIAL CHANGE.
DRY WARM AND HUMID MOST OF FRI WITH MAX KI 31. A NEW AREA OF SCT
STRONG/ISOLATED SVR TSTMS IS EXPECTED TO ARRIVE AFTER 20Z IN E PA
AND MD REACHING DE/W NJ NEAR 00Z/29 AS KI INCREASES INTO THE MID
30S AND 0-6KM BULK SHEAR LOOKS TO BE A BIT MORE THAN THAT OF TODAY
AND IT HAS OVER 1000J OF ML CAPE TO WORK WITH GOOD TIMING ON THE
HEAT OF THE DAY...AGAIN NEAR 90F POTENTIAL IN THE PHILADELPHIA
AREA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THIS LOW WILL CONTINUE TO LIFT INTO CANADA OVER THE WEEKEND,
WHILE THE COLD FRONT STALLS ACROSS THE EAST COAST. A CLOSED LOW
ALOFT MOVING THROUGH THE GREAT LAKES FRIDAY INTO SATURDAY IS
FORECAST TO DEVELOP INTO A LONG WAVE TROUGH AND EXTEND FROM
EASTERN CANADA, THROUGH THE GREAT LAKES, AND INTO THE CENTRAL GULF
STATES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP
MULTIPLE SHORT WAVE/VORTICITY IMPULSES MOVING ACROSS OUR AREA
THROUGH THE PERIOD. THIS, COMBINED WITH THE PROXIMITY OF THE
FRONTAL BOUNDARY WILL KEEP A CHANCE OF SHOWERS/THUNDERSTORMS IN
THE FORECAST EACH DAY.
A BERMUDA HIGH PRESSURE TO OUR EAST OVER THE ATLANTIC IS FORECAST TO
BEGIN PUSHING BACK WESTWARD BY THE MIDDLE OF NEXT WEEK. THIS WOULD
LIKELY EITHER PUSH THE FRONTAL BOUNDARY BACK TO OUR WEST, OR HELP IT
WASH OUT OVER THE AREA. A CLOSED LOW ALOFT MAY ONCE AGAIN DEVELOP
ACROSS THE CENTRAL PORTION OF THE COUNTRY, WHILE RIDGING ALOFT DEVELOPS
JUST OFFSHORE OF THE ATLANTIC COAST. EVEN WITHOUT THE FRONTAL
BOUNDARY FOR A FOCUS, ANY SHORT WAVE/VORTICITY IMPULSES COULD HELP
CREATE SHOWERS/THUNDERSTORMS ACROSS THE AREA, HENCE WE KEEP A
CHANCE OF SHOWERS/THUNDERSTORMS IN THE FORECAST INTO THE MIDDLE OF
NEXT WEEK.
WITH A WARM, MOIST AIRMASS REMAINING ACROSS THE AREA, THERE WILL
BE INSTABILITY EACH DAY. IN ADDITION, PW VALUES WILL REMAIN AROUND
1.5-2 INCHES. THEREFORE, EACH DAY THERE WILL BE THE POTENTIAL FOR
STRONG THUNDERSTORMS WITH HEAVY RAIN.
WITH A GENERAL SOUTHWEST FLOW ACROSS THE AREA AND THICKNESSES
REMAINING FAIRLY STEADY, TEMPERATURES THROUGH THE EXTENDED ARE NOT
EXPECTED TO RISE SHARPLY. THEREFORE, HIGH TEMPERATURES ARE FORECAST
TO BE FAIRLY CLOSE TO NORMAL OR A COUPLE OF DEGREES ABOVE, ALTHOUGH
LOW TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...LOCAL MVFR VSBY BECOME VFR SCT CLOUDS AOA 5000 FT AND A GENERAL
S-SW WIND G10-15 KT. IFR CONDS IN SW G30-40KT IN TORRENTIAL RAIN
PRODUCING TSTMS EXPECTED AFTER 20Z IN E PA REACHING NJ AROUND 00Z.
TONIGHT...IFR PRODUCING TSTMS END FM SW TO NE DURING THE NIGHT WITH
MVFR OR IFR CONDS IN ST/FOG...LIGHT WIND AND NO THUNDER POTENTIAL
EXPECTED AFTER 07Z MOST TAF LOCATIONS.
FRIDAY...AFTER ANY MORNING MVFR/IFR FOG BURNS OFF BY 14Z...VFR SCT-
BKN CLOUDS AOA 5000 FT WITH SW WIND G15-20KT. TSTM POTENTIAL AFTER
20Z.
OUTLOOK...
FRIDAY NIGHT THROUGH MONDAY...GENERALLY VFR WITH PERIODS OF
MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND
MORNING LOW CLOUDS/FOG.
&&
.MARINE...
SCA IS POSTED.
WW3 GFS MODEL RUNNING A LITTLE HIGH IN WAA (TYPICAL BIAS) AND 12Z
SWELL IS 2 FT 6 SEC AND FCST TOO HIGH BY 1-2FT. THAT TREND SHOULD
CONTINUE THOUGH EVENTUALLY SCA SEAS 5 FT OR HIGHER SHOULD ARRIVE
IN THE ATLC WATERS TONIGHT. ONCE 5 FT ARRIVES...IT WILL BE SLOW TO
SUBSIDE IN THE FUTURE AS A PERSISTENT SLY FLOW CONTINUES SEEMINGLY
FOR AT LEAST ANOTHER WEEK ON THE WATERS.
CONDITIONS ARE ANTICIPATED TO REMAIN BELOW ADVISORY CRITERIA ON
DELAWARE BAY WHERE SWELL IS MUCH LESS A FACTOR EXCEPT AT THE BAY
ENTRANCE.
SHOWERS AND SOME THUNDERSTORMS ARE FORECAST TO DEVELOP AND BECOME
MORE NUMEROUS TONIGHT. SOME TSTORMS COULD PRODUCE SW GUSTS 30-35 KT.
OUTLOOK...
THE SMALL CRAFT ADVISORY CONDITIONS COULD LAST ON THE WATERS FOR
A FEW DAYS AS SEAS ARE FORECAST TO REMAIN AROUND 5 FEET THROUGH
MONDAY. WINDS COULD ALSO PERIODICALLY GUST AROUND 25 KNOTS OVER
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
AN AREA OF LOW PRESSURE WILL MOVE FROM THE GREAT LAKES INTO NEW
ENGLAND TODAY AND TONIGHT. AN INCREASE IN THE SOUTHERLY FLOW WILL
HELP PULL PW VALUES TO AROUND 2 INCHES ACROSS OUR AREA. THE LARGE
SCALE LIFT IS FORECAST TO BE THE STRONGEST ACROSS NORTHEASTERN
PENNSYLVANIA AND NORTHERN NEW JERSEY. THIS SHOULD RESULT IN A BETTER
ORGANIZED AREA OF SHOWERS AND EMBEDDED THUNDER WITH THE POTENTIAL
FOR VERY HEAVY RAINFALL AT TIMES. RAINFALL AMOUNTS IN EXCESS OF ONE
INCH IS QUITE POSSIBLE, PARTICULARLY ACROSS NORTHERN NEW JERSEY AND
THE POCONOS. THE LATEST FLASH FLOOD GUIDANCE INDICATES THAT THIS
AMOUNT OF RAIN LATE TODAY AND TONIGHT COULD CAUSE SOME FLASH
FLOODING. THE LOWEST FLASH FLOOD GUIDANCE IS ACROSS PORTIONS OF FAR
NORTHERN NEW JERSEY AND THEREFORE THE FLASH FLOOD WATCH REMAINS IN
EFFECT FOR SUSSEX, WARREN AND MORRIS COUNTIES STARTING LATE TODAY.
WE THOUGHT ABOUT EXPANDING THE WATCH TO INCLUDE NORTHAMPTON, CARBON
AND MONROE COUNTIES HOWEVER THE FLASH FLOOD GUIDANCE IS MUCH HIGHER
HERE. THE MAIN CONCERN ACROSS THESE COUNTIES IS THAT TERRAIN COULD
PLAY A ROLE WITH ADDED RUNOFF ESPECIALLY WITH HIGHER RAINFALL RATES.
IF THIS POTENTIAL LOOKS TO INCREASE, THEN THE WATCH CAN ALWAYS BE
EXPANDED. ELSEWHERE, MOSTLY LOCALIZED NUISANCE TYPE FLOODING MAY
OCCUR DURING THE HEAVIEST DOWNPOURS.
&&
.RIP CURRENTS...
THERE IS A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW
JERSEY COAST TODAY INTO TONIGHT, MOSTLY DUE TO A SOUTHERLY FLOW AND
A BIT OF AN INCREASE IN THE SWELL PERIOD. IF THE SWELL IS ONLY 3
FT 6 SEC AT 18Z...AND THE WIND S 15KT WE WILL LOWER THE RISK TO
LOW AND UPDATE THE SRF.
AS IT STANDS WE ARE PROJECTING AT WORST A 4 FT 6 SEC SSE SWELL AT
18Z AND A S WIND 15 KT. EVEN THAT GIVES US A LOW RISK ON THE CUSP OF
MDT.
NO MATTER...THERE IS A RISK OF SIGNIFICANT RIP CURRENT FORMATION
THIS AFTERNOON.
FOR FRIDAY...WW3 IS PROJECTING A 5 FT 8 SEC SSE SWELL WITH A S WIND
15 KT. THAT EASILY PUTS US IN THE MDT CATEGORY FOR NJ AND MARGINAL
LOW-MDT FOR DE.
A MDT RISK FOR DANGEROUS RIP CURRENT FORMATION IS PROJECTED THROUGH
AT LEAST MONDAY AS THE SWELL SHOULD BE NEAR 6 FT WITH A 7 TO 8 SEC
PERIOD.
&&
.CLIMATE...
WE`LL ADD MONTHLY CLI INFORMATION LATER TODAY AS TIME AVAILS.
WARMER THAN NORMAL DAILY AS A PERSISTENT HUMID SSW SFC FLOW
PREVAILS...PROBABLY FOR AT LEAST THE NEXT 10-14 DAYS PER 00Z/27 NAEFS
AND 00Z/27 RMOP WHICH DISAGREE WITH THE 00Z/27 ECMWF OP RUN OF BIG
TROF IN THE NE USA DAY 9-10 .. JULY 5-6
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH FRIDAY
MORNING FOR NJZ001-007-008.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT
FRIDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG/GORSE 910
SHORT TERM...DRAG/GORSE 910
LONG TERM...ROBERTSON
AVIATION...DRAG/GORSE/ROBERTSON 910
MARINE...DRAG/GORSE/ROBERTSON 910
HYDROLOGY...
RIP CURRENTS...910
CLIMATE...910
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
954 PM EDT Fri Jun 28 2013
.NEAR TERM [Through 12Z Tomorrow]...
Will continue to see a gradual weakening pattern of storms as they
move east into a more unfavorable environment. Rain has mostly ended
in our western CWA, namely SE Alabama and the far western Panhandle.
For the remaining CWA, expect showers ending by late tonight.
A shortwave currently moving through the Lower Mississippi Valley is
providing upper level support for a line of thunderstorms currently
moving through central Alabama. High-Res models such as the HRRR
continue to show the shortwave moving through our area, and along
with it another a line of thunderstorms with the potential for
producing some isolated severe thunderstorms. If severe weather
does occur, it would be damaging wind gusts. The HRRR over the
past few days and today have handled placement and strength of
convection fairly well, so have put more confidence in its current
evolution of storms throughout the night and into the early
morning. Early in the early morning hours thunderstorms move into
our SE Alabama counties and becomes more organized in a linear
complex by sunrise from around Bainbridge extending SW through Panama
City and its adjacent offshore waters.
Other than the rain, expect a mostly cloudy night with lows in the
mid to lower 70s.
&&
.SHORT TERM [Through Saturday Night]...
Upper trough axis (currently along the eastern seaboard) will
retrograde to the west tonight into Saturday, with the axis
ending up west of the forecast area. In addition, a frontal
boundary will drop south into the area by Saturday and stall
across SE Alabama and the Florida Panhandle. This will create a
favorable pattern for convection, especially east of the
Apalachicola/Chattahoochee Rivers, with a very moist airmass and
weak shortwave energy rounding the base of the trough. As with
Friday morning, the convection may get an early start along the
coast, so will have relatively high PoPs in place throughout the
day. Conditions will change little by Sunday, with the eastern
half of the area favored once again.
&&
.LONG TERM [Sunday through Friday]...
Unseasonably deep trough will be in place over the eastern half of
the country through next week. This will keep moist and deep
southwesterly flow across the forecast area with enhanced rain
chances for most of the week. Periods of more widespread rain will
likely be governed by timing of weak upper/lower level features,
which are difficult to predict this far out. Therefore, will
continue with a general forecast of likely PoPs for the eastern
half of area early in the week, with the higher PoPs spreading
west by midweek as the upper level trough slowly retrogrades.
&&
.AVIATION [Through 00Z Sunday]...
Expect rain showers continuing for our eastern terminals TLH, VLD,
and ABY, but shouldn`t have any flight restrictions outside of
thunderstorms expected in the early morning hours. Tomorrow
afternoon should be a bit gusty with gusts around 20 knots out of
the S/SE, but VFR conditions will prevail.
&&
.MARINE...
Southwesterly flow will be on the increase through the weekend as
the Bermuda high strengthens over the western Atlantic and a
frontal boundary approaches the northern Gulf Coast. Expect
exercise caution conditions to develop overnight and continue
through most of the weekend. Brief periods of advisory level
winds will be possible late Saturday into Sunday.
&&
.FIRE WEATHER...
Red flag conditions are not expected due to above average relative
humidity values throughout the period.
&&
.HYDROLOGY...
A wet weather pattern will be in place through the
weekend and into early next week. Widespread 2 to 4 inch rainfall
amounts are anticipated through Monday, with isolated higher
amounts. With no area rivers in flood or action stage, no
river flooding is expected. However, locally heavy rainfall may
cause flooding of some urban and/or low-lying areas.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 77 90 74 89 72 / 30 70 50 70 40
Panama City 78 87 79 87 77 / 50 60 50 60 30
Dothan 73 92 72 91 71 / 50 60 40 50 30
Albany 75 91 73 89 71 / 10 60 40 60 40
Valdosta 74 89 73 88 72 / 30 70 50 70 50
Cross City 78 88 74 88 73 / 60 70 60 70 50
Apalachicola 81 86 79 86 77 / 50 60 60 60 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Navarro/Harrigan
SHORT TERM...Camp
LONG TERM...Camp
AVIATION...Navarro/Harrigan
MARINE...Camp
FIRE WEATHER...Camp
HYDROLOGY...Camp
AREA FORECAST DISCUSSION
NWS MIAMI FL
849 PM EDT FRI JUN 28 2013
.UPDATE...
MAIN AREA OF CONVECTION REMAINS THIS EVENING ACROSS COASTAL PALM
BEACH COUNTY WITH ONLY ISOLATED SHOWERS AND THUNDERSTORMS ACROSS
THE REMAINDER OF THE SOUTH FLORIDA AREA. LATEST SHORT TERM
GUIDANCE KEEPS PARTLY TO MOSTLY CLOUDY SKIES ACROSS THE AREA WITH
REMAINING SHOWERS AND STORMS CONFINED ACROSS MAINLY THE REGIONAL
WATERS OVERNIGHT. UPDATED POP AND QPF GRIDS TO ACCOUNT FOR THE
LATEST TRENDS. UPDATE SENT.
&&
.PREV DISCUSSION... /ISSUED 727 PM EDT FRI JUN 28 2013/
AVIATION...
TSTMS STILL ACTIVE AT PRESENT JUST INLAND FROM THE PRIMARY EAST
COAST TERMINAL SITES, WITH A SLOW MOTION TO THE NE AS THEY
GRADUALLY WEAKEN. VCTS INCLUDED AT ALL EAST COAST SITES THROUGH
02Z WHICH IS WHEN MOST OF THE TSTMS SHOULD DISSIPATE. VFR
CONDITIONS SHOULD PREVAIL DURING THIS PERIOD AS CORE OF THE STORMS
SHOULD STAY JUST TO THE WEST, BUT BRIEF MVFR PERIODS CERTAINLY
POSSIBLE. PREVAILING S/SW FLOW WILL CONTINUE THROUGH SATURDAY WITH
MIDDAY/AFTERNOON SHRA/TSRA PRIMARILY INTERIOR AND EAST COAST. GULF
COAST/KAPF SHOULD MISS OUT ON MOST OF THE SHRA/TSRA SATURDAY AFTERNOON,
WITH SOME MORNING SHOWERS POSSIBLE. /MOLLEDA
PREV DISCUSSION... /ISSUED 222 PM EDT FRI JUN 28 2013/
SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)...
CURRENTLY, SOUTH FLORIDA CONTINUES TO BE MAINLY INFLUENCED BY THE
DEEP LAYER RIDGE WHICH STRETCHES ACROSS THE REGION INTO THE
ATLANTIC. THIS HAS RESULTED IN MAINTAINING A STEERING FLOW THAT IS
NEARLY NONEXISTENT WITH ERRATIC STORM MOTION. HOWEVER, AS THE DAY
PROGRESSES A MID LEVEL TROUGH WILL BE DEEPENING ACROSS THE EASTERN
U.S. WHICH IN TURN WILL SHIFT THE RIDGE BOTH ALOFT AND AT THE
SURFACE INTO THE FLORIDA STRAITS BY TONIGHT. HINTS OF THIS OCCURRING ARE
BECOMING EVIDENT IN THE RADAR AND SATELLITE SIGNATURES WITH A
VERY SLOW DRIFT TO THE NORTHEAST. THE HRRR IS COMING MORE IN LINE
WITH THAT THINKING ALSO. THE ONLY CONCERN IS THAT THE HRRR ALSO IS
SHOWING GOOD DEVELOPMENT BY 18Z WHICH HAS YET TO OCCUR SO TRENDED
LATER WITH THE HIGHER CHANCES OF CONVECTION.
GLOBAL MODELS CONTINUE WITH THE EVOLUTION OF THE TROUGH DEEPENING
IT THROUGH SUNDAY. AS THIS OCCURS, THE STEERING FLOW WILL BECOME
MORE SOUTHWEST ON SATURDAY WITH THE HIGHEST CHANCES FOR RAIN OVER
THE INTERIOR AND MOST OF THE EAST COAST METRO REGION. THE PRIMARY
THREAT WILL BE LOCALLY HEAVY RAINFALL POSSIBLE ALTHOUGH STORM
MOTION WILL PICK UP TO BETWEEN 5 AND 10 KNOTS AND RELATIVELY WEAK
MID LEVEL LAPSE RATES. THE MODELS ARE NOW SHOWING THE TROUGH
DEEPENING EVEN FURTHER ON SUNDAY WITH A BLOCKING PATTERN SETTING
UP ACROSS NORTH AMERICA AS MASSIVE RIDGES WILL BE IN EXISTENCE
OVER THE DESERT SOUTHWEST AND THE WESTERN ATLANTIC. THIS WILL ALSO
DEVELOP AN EVEN STRONGER DEEP SOUTHWEST STEERING FLOW. IN FACT,
FORECAST SOUNDINGS ARE SHOWING AROUND 20 KNOTS OF WIND IN THE LOW
LEVELS FROM ABOUT 2-7K FEET AND THIS ALONG WITH MID LEVEL LAPSE
RATES STILL NOT VERY IMPRESSIVE COULD LIMIT THE AMOUNT OF THUNDER.
THE KEY FACTOR WILL BE IF A EAST COAST SEA BREEZE WILL BE ABLE TO
DEVELOP WITH SUCH STRONG LOW LEVEL SOUTHWEST WINDS. THE PWAT IS
FORECAST TO BE WELL ABOVE TWO INCHES SO CHANCES FOR RAIN WILL
REMAIN HIGH BUT THERE COULD BE ONLY A FEW LIGHTNING STRIKES
ESPECIALLY WITH THE CONVECTION THAT DEVELOPS EARLY IN THE DAY. AT
THE SAME TIME HOWEVER, BOTH THE MAV AND MET GUIDANCE ARE SHOWING
VERY HIGH CHANCES FOR THUNDER. SO FOR THE TIME BEING WILL NOT
CHANGE THE FORECAST FOR SUNDAY AND WILL WAIT FOR FURTHER GUIDANCE
TO MAKE A DECISION ON WHETHER TO LOWER CHANCES FOR LIGHTNING
STRIKES. ALL IN ALL THOUGH, IT IS SHAPING UP TO BE A WET WEEKEND
FOR THE EAST COAST METRO REGION ESPECIALLY ON SUNDAY.
LONG TERM (MONDAY THROUGH FRIDAY)...
THE BLOCKING PATTERN WILL CONTINUE INTO EARLY NEXT WEEK WITH A
VERY SLOW RETROGRESSION TO THE WEST IN THE OVERALL PATTERN BY THE
MIDDLE OF NEXT WEEK. THIS WILL RESULT IN THE DEEP LAYER RIDGE
EVER SO SLOWLY SHIFTING BACK TO THE NORTH. SO FOR TUESDAY,
FORECAST SOUNDINGS ARE INDICATING A STEERING FLOW MORE SOUTHERLY
AND THEN RETURNING TO A SOUTHEAST DIRECTION BY WEDNESDAY OR
THURSDAY. THE PWAT WILL REMAIN AT NEAR TWO INCHES ALL OF NEXT WEEK
SO THE CHANCES FOR RAIN WILL REMAIN HIGH BUT SHIFT BACK TO THE
INTERIOR AND SOUTHWEST COAST BY WEDNESDAY THROUGH FRIDAY.
MARINE... THE WIND WILL BE MAINTAIN A SOUTH TO SOUTHWEST
DIRECTION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE SEAS
WILL BUILD SLIGHTLY BY SUNDAY IN RESPONSE TO A TIGHTENING PRESSURE
GRADIENT AND INCREASE IN SPEED AS A STRONG TROUGH DEEPENS OVER THE
EASTERN STATES. A SCEC STATEMENT MAY BE NEEDED FOR A PORTION OF
THE WATERS AS SPEEDS COULD INCREASE IN THE RANGE OF 15 TO 20
KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 89 77 89 / 70 50 30 70
FORT LAUDERDALE 75 88 79 89 / 40 50 40 70
MIAMI 77 90 78 90 / 40 40 40 70
NAPLES 75 91 76 91 / 20 40 30 70
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...59/RM
AREA FORECAST DISCUSSION
NWS MIAMI FL
727 PM EDT FRI JUN 28 2013
.AVIATION...
TSTMS STILL ACTIVE AT PRESENT JUST INLAND FROM THE PRIMARY EAST
COAST TERMINAL SITES, WITH A SLOW MOTION TO THE NE AS THEY
GRADUALLY WEAKEN. VCTS INCLUDED AT ALL EAST COAST SITES THROUGH
02Z WHICH IS WHEN MOST OF THE TSTMS SHOULD DISSIPATE. VFR
CONDITIONS SHOULD PREVAIL DURING THIS PERIOD AS CORE OF THE STORMS
SHOULD STAY JUST TO THE WEST, BUT BRIEF MVFR PERIODS CERTAINLY
POSSIBLE. PREVAILING S/SW FLOW WILL CONTINUE THROUGH SATURDAY WITH
MIDDAY/AFTERNOON SHRA/TSRA PRIMARILY INTERIOR AND EAST COAST. GULF
COAST/KAPF SHOULD MISS OUT ON MOST OF THE SHRA/TSRA SATURDAY AFTERNOON,
WITH SOME MORNING SHOWERS POSSIBLE. /MOLLEDA
&&
.PREV DISCUSSION... /ISSUED 222 PM EDT FRI JUN 28 2013/
SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)...
CURRENTLY, SOUTH FLORIDA CONTINUES TO BE MAINLY INFLUENCED BY THE
DEEP LAYER RIDGE WHICH STRETCHES ACROSS THE REGION INTO THE
ATLANTIC. THIS HAS RESULTED IN MAINTAINING A STEERING FLOW THAT IS
NEARLY NONEXISTENT WITH ERRATIC STORM MOTION. HOWEVER, AS THE DAY
PROGRESSES A MID LEVEL TROUGH WILL BE DEEPENING ACROSS THE EASTERN
U.S. WHICH IN TURN WILL SHIFT THE RIDGE BOTH ALOFT AND AT THE
SURFACE INTO THE FLORIDA STRAITS BY TONIGHT. HINTS OF THIS OCCURRING ARE
BECOMING EVIDENT IN THE RADAR AND SATELLITE SIGNATURES WITH A
VERY SLOW DRIFT TO THE NORTHEAST. THE HRRR IS COMING MORE IN LINE
WITH THAT THINKING ALSO. THE ONLY CONCERN IS THAT THE HRRR ALSO IS
SHOWING GOOD DEVELOPMENT BY 18Z WHICH HAS YET TO OCCUR SO TRENDED
LATER WITH THE HIGHER CHANCES OF CONVECTION.
GLOBAL MODELS CONTINUE WITH THE EVOLUTION OF THE TROUGH DEEPENING
IT THROUGH SUNDAY. AS THIS OCCURS, THE STEERING FLOW WILL BECOME
MORE SOUTHWEST ON SATURDAY WITH THE HIGHEST CHANCES FOR RAIN OVER
THE INTERIOR AND MOST OF THE EAST COAST METRO REGION. THE PRIMARY
THREAT WILL BE LOCALLY HEAVY RAINFALL POSSIBLE ALTHOUGH STORM
MOTION WILL PICK UP TO BETWEEN 5 AND 10 KNOTS AND RELATIVELY WEAK
MID LEVEL LAPSE RATES. THE MODELS ARE NOW SHOWING THE TROUGH
DEEPENING EVEN FURTHER ON SUNDAY WITH A BLOCKING PATTERN SETTING
UP ACROSS NORTH AMERICA AS MASSIVE RIDGES WILL BE IN EXISTENCE
OVER THE DESERT SOUTHWEST AND THE WESTERN ATLANTIC. THIS WILL ALSO
DEVELOP AN EVEN STRONGER DEEP SOUTHWEST STEERING FLOW. IN FACT,
FORECAST SOUNDINGS ARE SHOWING AROUND 20 KNOTS OF WIND IN THE LOW
LEVELS FROM ABOUT 2-7K FEET AND THIS ALONG WITH MID LEVEL LAPSE
RATES STILL NOT VERY IMPRESSIVE COULD LIMIT THE AMOUNT OF THUNDER.
THE KEY FACTOR WILL BE IF A EAST COAST SEA BREEZE WILL BE ABLE TO
DEVELOP WITH SUCH STRONG LOW LEVEL SOUTHWEST WINDS. THE PWAT IS
FORECAST TO BE WELL ABOVE TWO INCHES SO CHANCES FOR RAIN WILL
REMAIN HIGH BUT THERE COULD BE ONLY A FEW LIGHTNING STRIKES
ESPECIALLY WITH THE CONVECTION THAT DEVELOPS EARLY IN THE DAY. AT
THE SAME TIME HOWEVER, BOTH THE MAV AND MET GUIDANCE ARE SHOWING
VERY HIGH CHANCES FOR THUNDER. SO FOR THE TIME BEING WILL NOT
CHANGE THE FORECAST FOR SUNDAY AND WILL WAIT FOR FURTHER GUIDANCE
TO MAKE A DECISION ON WHETHER TO LOWER CHANCES FOR LIGHTNING
STRIKES. ALL IN ALL THOUGH, IT IS SHAPING UP TO BE A WET WEEKEND
FOR THE EAST COAST METRO REGION ESPECIALLY ON SUNDAY.
LONG TERM (MONDAY THROUGH FRIDAY)...
THE BLOCKING PATTERN WILL CONTINUE INTO EARLY NEXT WEEK WITH A
VERY SLOW RETROGRESSION TO THE WEST IN THE OVERALL PATTERN BY THE
MIDDLE OF NEXT WEEK. THIS WILL RESULT IN THE DEEP LAYER RIDGE
EVER SO SLOWLY SHIFTING BACK TO THE NORTH. SO FOR TUESDAY,
FORECAST SOUNDINGS ARE INDICATING A STEERING FLOW MORE SOUTHERLY
AND THEN RETURNING TO A SOUTHEAST DIRECTION BY WEDNESDAY OR
THURSDAY. THE PWAT WILL REMAIN AT NEAR TWO INCHES ALL OF NEXT WEEK
SO THE CHANCES FOR RAIN WILL REMAIN HIGH BUT SHIFT BACK TO THE
INTERIOR AND SOUTHWEST COAST BY WEDNESDAY THROUGH FRIDAY.
AVIATION...
WITH THE WINDS SHIFTING MORE TO THE SOUTH, CONVECTIVE ACTIVITY HAS
BEEN MORE CHAOTIC. THE BERMUDA HIGH HAS WEAKENED, ALLOWING FOR
MORE INSTABILITY. HOWEVER, THIS HAS JUST LEAD TO MANY SMALL, WEAK
SHOWERS AND THUNDERSTORMS, RATHER THAN LARGE STRONG STORMS. GIVEN
THIS, HAVE REDUCED COVERAGE OF VCTS IN THE TAF SITES FROM KFLL
NORTH, ALTHOUGH, THEY MAY NEED TO BE ADDED BACK IN LATER TODAY.
WITH ACTIVITY PERSISTING FROM KOPF, SOUTH, HAVE KEPT THE VCTS IN,
AS WELL AS FOR KAPF. WINDS, DUE TO THE CONVECTION, HAVE ALSO BEEN
CHAOTIC TODAY. HOWEVER, THEY SHOULD BECOME SOUTHERLY AS CONVECTION
WANES ALONG THE COAST, WHICH APPEARS SOME SITES HAVE ALREADY BEGUN
THE SHIFT. TONIGHT, WINDS WILL BECOME LIGHT AND VARIABLE AND
CONVECTION SHOULD DIMINISH AFTER SUNSET. TOMORROW WILL SEE WINDS
BECOME MORE SOUTHWESTERLY AND ANOTHER ROUND OF CONVECTION WILL
BEGIN MID TO LATE MORNING.
MARINE...
THE WIND WILL BE MAINTAIN A SOUTH TO SOUTHWEST DIRECTION THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK. THE SEAS WILL BUILD SLIGHTLY
BY SUNDAY IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT AND
INCREASE IN SPEED AS A STRONG TROUGH DEEPENS OVER THE EASTERN
STATES. A SCEC STATEMENT MAY BE NEEDED FOR A PORTION OF THE WATERS
AS SPEEDS COULD INCREASE IN THE RANGE OF 15 TO 20 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 89 77 89 / 50 50 30 70
FORT LAUDERDALE 75 88 79 89 / 50 50 40 70
MIAMI 77 90 78 90 / 40 40 40 70
NAPLES 75 91 76 91 / 20 40 30 70
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE...10/CD
AVIATION/RADAR...59/MOLLEDA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1032 AM EDT THU JUN 27 2013
.UPDATE...
NO MAJOR CHANGES ARE PLANNED FOR THE MORNING UPDATES. RADAR
SIGNATURES SHOWING SHOWERS/THUNDERSTORMS HAVE BEEN DEVELOPING OVER
THE INTERIOR AND ALONG THE EAST COAST SEA BREEZE WITH STORM MOTION
NEARLY STATIONARY AND THIS SHOWS UP WELL IN THE 12Z MFL SOUNDING
WITH ERRATIC WIND DIRECTIONS UP THROUGH 20-25K FEET AT SPEEDS OF
LESS THAN 5 KNOTS. THE POP GRIDS HAVE HANDLED THIS WELL. THE
OVERALL TREND SHOULD BE THE ACTIVITY WILL TRANSITION TO MOVE TO THE INTERIOR
AS THE AFTERNOON PROGRESSES WITH THE SEA BREEZES MOVING FARTHER
INLAND. THE HRRR HAS HAD GOOD TIMING IN THE FORMATION OF THE CELLS
BUT HAS BEEN TOO FAR SOUTH BUT STILL SHOWS MORE DEVELOPMENT
FARTHER INLAND AFTER 17-18Z AND THIS SEEMS REASONABLE.
KOB
&&
.PREV DISCUSSION... /ISSUED 750 AM EDT THU JUN 27 2013/
AVIATION...
SOUTHEASTERLY FLOW AROUND A BERMUDA HIGH WILL CONTINUE TODAY. THE
HIGH IS WEAKENING SOME, SO FLOW SHOULD BE LIGHTER THAN YESTERDAY.
WITH THIS FLOW, PLENTY OF MOISTURE WILL CONTINUE TO BE BROUGHT INTO
SOUTH FLORIDA. THIS WILL BRING ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS TO THE AREA TODAY. WITH THE LIGHTER FLOW, THE SPEED
OF THE CONVECTIVE CELLS WILL BE SLOWER, WHICH WOULD ALLOW FOR MORE
PRECIPITATION IN ONE LOCATION, WHICH COULD REDUCE VSBY FOR MORE
THAN A BRIEF MOMENT, IF A CELL DEVELOPED IN VC OF A TAF SITE.
CURRENTLY, JUST RANGE FROM VCSH THIS MORNING TO VCTS THIS
AFTERNOON. THESE SHOULD ONCE AGAIN DIMINISH AFTER SUNSET THIS
EVENING AND VFR SHOULD BR THE GENERAL RULE FOR MOST OF THE TAF
PERIOD.
PREV DISCUSSION... /ISSUED 420 AM EDT THU JUN 27 2013/
DISCUSSION...
AN IMPRESSIVE RIDGE OF HIGH PRESSURE OVER THE FOUR CORNERS REGION
WILL ALLOW FOR AN UNUSUALLY DEEP TROUGH TO DEVELOP OVER THE
EASTERN CONUS INTO THE WEEKEND. THE TROUGH WILL DIG SOUTHWARD INTO
THE SOUTHEAST ON FRIDAY AND INTO NORTH FLORIDA OVER THE WEEKEND.
THE SURFACE RIDGE AXIS WILL PUSH SOUTHWARD TO NEAR LAKE OKEECHOBEE
THIS AFTERNOON AND THEN SLIDE SOUTH OF THE REGION ON FRIDAY
THROUGH THE WEEKEND.
ISOLATED SHOWERS WERE BEGINNING TO DEVELOP OVER THE ATLANTIC AND
ACROSS PALM BEACH COUNTY. HRRR AND OTHER HIGH RES MODELS INDICATE
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP VERY NEAR THE
COAST ALONG THE SEA BREEZE THIS MORNING...WITH SCATTERED TO
NUMEROUS SHOWERS AND STORMS DEVELOPING ACROSS THE INTERIOR AND
WEST INTO THE AFTERNOON. WATERSPOUTS ARE POSSIBLE OVER THE
ATLANTIC WATERS...MAINLY THIS MORNING. IN ADDITION...SLOW MOVING
STORMS COULD LEAD TO LOCALIZED FLOODING ACROSS THE REGION.
SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE EVENING HOURS ACROSS
THE INTERIOR...WITH RAIN CHANCES SHIFTING TO THE COASTAL REGIONS
OVERNIGHT.
THE UPPER TROUGH OVER THE OHIO VALLEY WILL GET REINFORCED AND
AMPLIFY FRIDAY INTO THE WEEKEND BY A SERIES OF SHORTWAVES
ROTATING SOUTHWARD OUT OF CANADA. A MORE SOUTHERLY FLOW WILL
DEVELOP ON FRIDAY AS THE UPPER LEVEL TROUGH DEEPENS INTO THE
SOUTHEAST AND THE RIDGE PUSHES SOUTH AND EAST. PRECIPITABLE WATER
VALUES WILL REMAIN NEAR 2 INCHES...AND WEAK STEERING FLOW WILL
MAINTAIN A LOCALLY HEAVY RAINFALL THREAT ONCE AGAIN. SOUTH TO
SOUTHWEST FLOW WILL THEN DEVELOP OVER THE WEEKEND WITH SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY.
THE UPPER LEVEL TROUGH WILL BEGIN TO RETROGRADE INTO THE MIDDLE OF
THE NATION EARLY NEXT WEEK. THE FLOW WILL THEN SHIFT BACK TO THE
SOUTHEAST. HOWEVER...DEEP MOISTURE WILL REMAIN ACROSS THE
REGION...WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS EACH
DAY.
AVIATION...
VFR CONDITIONS ARE EXPECTED FOR THIS MORNING FOR ALL TERMINALS.
INCREASING MOISTURE BY DAYBREAK COULD TRIGGER A FEW SHOWERS OVER
THE ATLANTIC COASTAL WATERS. WINDS TURN SOUTHEASTERLY TODAY AND
MORE SOUTHERLY ON FRIDAY. KEPT VCSH FOR ALL TERMINALS STARTING
AROUND 14Z. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER
THE COASTAL WATERS AS THE DAY PROGRESSES WITH THE HIGHEST
CONCENTRATION OF THUNDERSTORMS IN THE INTERIOR SECTIONS IN THE
AFTERNOON AND EVENING.
MARINE...
BY FRIDAY AND INTO THE WEEKEND SOUTHERLY TO SOUTHWESTERLY WINDS
MAINLY BELOW 15 KNOTS ARE FORECAST ACROSS THE REGIONAL WATERS WITH
GULF AND ATLANTIC SEAS 3 FEET OR BELOW THROUGH THE FORECAST PERIOD.
FIRE WEATHER...
AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS THE
PENINSULA THURSDAY AND FRIDAY AFTERNOONS AND EARLY EVENING.
OTHERWISE NO OTHER FIRE WEATHER CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 89 78 / 50 30 60 40
FORT LAUDERDALE 89 78 89 75 / 50 30 50 30
MIAMI 90 77 89 77 / 50 30 40 30
NAPLES 90 74 88 76 / 40 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1020 AM EDT THU JUN 27 2013
.DISCUSSION...
.UPDATE...CENTRAL FL SOUNDINGS SHOW 1.83 INCHES PRECIP WATER WITH
CONVECTIVE ACTIVITY ALREADY DEVELOPING OVER PALM BEACH COUNTY SOUTH
OF THE LOW LVL RIDGE AXIS NEAR LAKE OKEECHOBEE. 10Z CAPE SOUNDING
INDICATES A BIT MORE WSW LOW LVL FLOW THAN MODEL PROGS SO EXPECT E
COAST BRZ MAY BE DELAYED A BUT NORTH OF SEBASTIAN AND INCH IN MORE
SLOWLY BREVARD COUNTY NORTHWARD. 12Z HRRR AND 00Z 4.5KM SPC WRF
SCATTERED COVERAGE ALONG E COAST SEA BREEZE AND MOVING INTO THE
INTERIOR LATER THIS AFTERNOON WITH E/W COAST SEA BREEZE INTERACTION
OVER SEMINOLE/ORANGE COUNTIES INTO THE SRN INTERIOR BY LATE
AFTERNOON. WNW/NW MID LAYER FLOW EXPECTED TO ALLOW SOME ACTIVITY TO
TEND TO DRIFT BACK TOWARD THE COAST LATE IN THE BAY...ESPEC NORTH OF
VRB. WITH THE SLIGHTLY STRONGER WSW LOW LVL FLOW AND WNW/NW STEERING
FLOW FOR LATE DAY ACTIVITY...INCREASED POPS TO 50 PCT FOR CSTL
SECTIONS FROM AROUND FORT PIERCE NORTHWARD. UPDATES AS WELL TO WIND
GRIDS TO DELAY EAST COAST SEA BRZ TIMING JUST A BIT ACROSS
CENTRAL/NRN CSTL ZONES.
&&
.AVIATION...EXPECT ISOLD-SCT TSRA TO DVLP INITIALLY ALONG E COAST
SEA BRZ FROM KMLB-KSUA BY 17Z...WITH SCT TSRA FOR INTERIOR TERMINALS
AFT 19Z WITH INTERACTIONS OF E/W COAST SEA BREEZES OVER KSFB-KMCO
20Z-22Z TIME FRAME. STEERING FLOW MAY ALLOW SOME STORMS TO DRIFT
BACK TWD THE COAST FROM KDAB-KTIX-KMLB IN THE EARLY EVENING.
&&
.MARINE...
MAIN ADJUSTMENT WAS TO LOWER SEAS TO AROUND 2 FT CSTL AND KEEP 2-3
FT OFFSHORE. WAVEWATCH/SWAN OVERFORECASTING BUOY 41009 THE LAST 12
HOURS. SOME LIGHTNING STORMS MAY MOVE BACK TWD THE COAST NORTH OF
SEBASTIAN INLET LATER THIS AFTERNOON AND EARLY EVENING.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
VOLKMER/SEDLOCK
AREA FORECAST DISCUSSION
NWS MIAMI FL
750 AM EDT THU JUN 27 2013
.AVIATION...
SOUTHEASTERLY FLOW AROUND A BERMUDA HIGH WILL CONTINUE TODAY. THE
HIGH IS WEAKENING SOME, SO FLOW SHOULD BE LIGHTER THAN YESTERDAY.
WITH THIS FLOW, PLENTY OF MOISTURE WILL CONTINUE TO BE BROUGHT INTO
SOUTH FLORIDA. THIS WILL BRING ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS TO THE AREA TODAY. WITH THE LIGHTER FLOW, THE SPEED
OF THE CONVECTIVE CELLS WILL BE SLOWER, WHICH WOULD ALLOW FOR MORE
PRECIPITATION IN ONE LOCATION, WHICH COULD REDUCE VSBY FOR MORE
THAN A BRIEF MOMENT, IF A CELL DEVELOPED IN VC OF A TAF SITE.
CURRENTLY, JUST RANGE FROM VCSH THIS MORNING TO VCTS THIS
AFTERNOON. THESE SHOULD ONCE AGAIN DIMINISH AFTER SUNSET THIS
EVENING AND VFR SHOULD BR THE GENERAL RULE FOR MOST OF THE TAF
PERIOD.
&&
.PREV DISCUSSION... /ISSUED 420 AM EDT THU JUN 27 2013/
DISCUSSION...
AN IMPRESSIVE RIDGE OF HIGH PRESSURE OVER THE FOUR CORNERS REGION
WILL ALLOW FOR AN UNUSUALLY DEEP TROUGH TO DEVELOP OVER THE
EASTERN CONUS INTO THE WEEKEND. THE TROUGH WILL DIG SOUTHWARD INTO
THE SOUTHEAST ON FRIDAY AND INTO NORTH FLORIDA OVER THE WEEKEND.
THE SURFACE RIDGE AXIS WILL PUSH SOUTHWARD TO NEAR LAKE OKEECHOBEE
THIS AFTERNOON AND THEN SLIDE SOUTH OF THE REGION ON FRIDAY
THROUGH THE WEEKEND.
ISOLATED SHOWERS WERE BEGINNING TO DEVELOP OVER THE ATLANTIC AND
ACROSS PALM BEACH COUNTY. HRRR AND OTHER HIGH RES MODELS INDICATE
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP VERY NEAR THE
COAST ALONG THE SEA BREEZE THIS MORNING...WITH SCATTERED TO
NUMEROUS SHOWERS AND STORMS DEVELOPING ACROSS THE INTERIOR AND
WEST INTO THE AFTERNOON. WATERSPOUTS ARE POSSIBLE OVER THE
ATLANTIC WATERS...MAINLY THIS MORNING. IN ADDITION...SLOW MOVING
STORMS COULD LEAD TO LOCALIZED FLOODING ACROSS THE REGION.
SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE EVENING HOURS ACROSS
THE INTERIOR...WITH RAIN CHANCES SHIFTING TO THE COASTAL REGIONS
OVERNIGHT.
THE UPPER TROUGH OVER THE OHIO VALLEY WILL GET REINFORCED AND
AMPLIFY FRIDAY INTO THE WEEKEND BY A SERIES OF SHORTWAVES
ROTATING SOUTHWARD OUT OF CANADA. A MORE SOUTHERLY FLOW WILL
DEVELOP ON FRIDAY AS THE UPPER LEVEL TROUGH DEEPENS INTO THE
SOUTHEAST AND THE RIDGE PUSHES SOUTH AND EAST. PRECIPITABLE WATER
VALUES WILL REMAIN NEAR 2 INCHES...AND WEAK STEERING FLOW WILL
MAINTAIN A LOCALLY HEAVY RAINFALL THREAT ONCE AGAIN. SOUTH TO
SOUTHWEST FLOW WILL THEN DEVELOP OVER THE WEEKEND WITH SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY.
THE UPPER LEVEL TROUGH WILL BEGIN TO RETROGRADE INTO THE MIDDLE OF
THE NATION EARLY NEXT WEEK. THE FLOW WILL THEN SHIFT BACK TO THE
SOUTHEAST. HOWEVER...DEEP MOISTURE WILL REMAIN ACROSS THE
REGION...WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS EACH
DAY.
AVIATION...
VFR CONDITIONS ARE EXPECTED FOR THIS MORNING FOR ALL TERMINALS.
INCREASING MOISTURE BY DAYBREAK COULD TRIGGER A FEW SHOWERS OVER
THE ATLANTIC COASTAL WATERS. WINDS TURN SOUTHEASTERLY TODAY AND
MORE SOUTHERLY ON FRIDAY. KEPT VCSH FOR ALL TERMINALS STARTING
AROUND 14Z. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER
THE COASTAL WATERS AS THE DAY PROGRESSES WITH THE HIGHEST
CONCENTRATION OF THUNDERSTORMS IN THE INTERIOR SECTIONS IN THE
AFTERNOON AND EVENING.
MARINE...
BY FRIDAY AND INTO THE WEEKEND SOUTHERLY TO SOUTHWESTERLY WINDS
MAINLY BELOW 15 KNOTS ARE FORECAST ACROSS THE REGIONAL WATERS WITH
GULF AND ATLANTIC SEAS 3 FEET OR BELOW THROUGH THE FORECAST PERIOD.
FIRE WEATHER...
AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS THE
PENINSULA THURSDAY AND FRIDAY AFTERNOONS AND EARLY EVENING.
OTHERWISE NO OTHER FIRE WEATHER CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 89 78 / 50 30 60 40
FORT LAUDERDALE 89 78 89 75 / 50 30 50 30
MIAMI 90 77 89 77 / 50 30 40 30
NAPLES 90 74 88 76 / 40 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...71/JE
AREA FORECAST DISCUSSION
NWS MIAMI FL
420 AM EDT THU JUN 27 2013
.DISCUSSION...
AN IMPRESSIVE RIDGE OF HIGH PRESSURE OVER THE FOUR CORNERS REGION
WILL ALLOW FOR AN UNUSUALLY DEEP TROUGH TO DEVELOP OVER THE
EASTERN CONUS INTO THE WEEKEND. THE TROUGH WILL DIG SOUTHWARD INTO
THE SOUTHEAST ON FRIDAY AND INTO NORTH FLORIDA OVER THE WEEKEND.
THE SURFACE RIDGE AXIS WILL PUSH SOUTHWARD TO NEAR LAKE OKEECHOBEE
THIS AFTERNOON AND THEN SLIDE SOUTH OF THE REGION ON FRIDAY
THROUGH THE WEEKEND.
ISOLATED SHOWERS WERE BEGINNING TO DEVELOP OVER THE ATLANTIC AND
ACROSS PALM BEACH COUNTY. HRRR AND OTHER HIGH RES MODELS INDICATE
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP VERY NEAR THE
COAST ALONG THE SEA BREEZE THIS MORNING...WITH SCATTERED TO
NUMEROUS SHOWERS AND STORMS DEVELOPING ACROSS THE INTERIOR AND
WEST INTO THE AFTERNOON. WATERSPOUTS ARE POSSIBLE OVER THE
ATLANTIC WATERS...MAINLY THIS MORNING. IN ADDITION...SLOW MOVING
STORMS COULD LEAD TO LOCALIZED FLOODING ACROSS THE REGION.
SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE EVENING HOURS ACROSS
THE INTERIOR...WITH RAIN CHANCES SHIFTING TO THE COASTAL REGIONS
OVERNIGHT.
THE UPPER TROUGH OVER THE OHIO VALLEY WILL GET REINFORCED AND
AMPLIFY FRIDAY INTO THE WEEKEND BY A SERIES OF SHORTWAVES
ROTATING SOUTHWARD OUT OF CANADA. A MORE SOUTHERLY FLOW WILL
DEVELOP ON FRIDAY AS THE UPPER LEVEL TROUGH DEEPENS INTO THE
SOUTHEAST AND THE RIDGE PUSHES SOUTH AND EAST. PRECIPITABLE WATER
VALUES WILL REMAIN NEAR 2 INCHES...AND WEAK STEERING FLOW WILL
MAINTAIN A LOCALLY HEAVY RAINFALL THREAT ONCE AGAIN. SOUTH TO
SOUTHWEST FLOW WILL THEN DEVELOP OVER THE WEEKEND WITH SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY.
THE UPPER LEVEL TROUGH WILL BEGIN TO RETROGRADE INTO THE MIDDLE OF
THE NATION EARLY NEXT WEEK. THE FLOW WILL THEN SHIFT BACK TO THE
SOUTHEAST. HOWEVER...DEEP MOISTURE WILL REMAIN ACROSS THE
REGION...WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS EACH
DAY.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED FOR THIS MORNING FOR ALL TERMINALS.
INCREASING MOISTURE BY DAYBREAK COULD TRIGGER A FEW SHOWERS OVER
THE ATLANTIC COASTAL WATERS. WINDS TURN SOUTHEASTERLY TODAY AND
MORE SOUTHERLY ON FRIDAY. KEPT VCSH FOR ALL TERMINALS STARTING
AROUND 14Z. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER
THE COASTAL WATERS AS THE DAY PROGRESSES WITH THE HIGHEST
CONCENTRATION OF THUNDERSTORMS IN THE INTERIOR SECTIONS IN THE
AFTERNOON AND EVENING.
&&
.MARINE...
BY FRIDAY AND INTO THE WEEKEND SOUTHERLY TO SOUTHWESTERLY WINDS
MAINLY BELOW 15 KNOTS ARE FORECAST ACROSS THE REGIONAL WATERS WITH
GULF AND ATLANTIC SEAS 3 FEET OR BELOW THROUGH THE FORECAST PERIOD.
&&
.FIRE WEATHER...
AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS THE
PENINSULA THURSDAY AND FRIDAY AFTERNOONS AND EARLY EVENING.
OTHERWISE NO OTHER FIRE WEATHER CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 89 78 / 30 30 60 40
FORT LAUDERDALE 89 78 89 75 / 20 30 50 30
MIAMI 90 77 89 77 / 20 30 40 30
NAPLES 90 74 88 76 / 40 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...71/JE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
708 PM EDT FRI JUN 28 2013
.SYNOPSIS...
A DEEPENING UPPER LEVEL TROUGH OVER THE EASTERN US...ALONG WITH
ABUNDANT MOISTURE...WILL PROVIDE ABOVE NORMAL CHANCES OF MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE
OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATE: EARLY EVENING TEMPERATURES STILL WARM AND HUMID...UPPER
80S TO LOWER 90S. MODERATE TO STRONG INSTABILITY ACROSS THE AREA
CONTINUES EARLY THIS EVENING. WITH SOME OF THE BEST INSTABILITY
VALUES ACROSS THE PIEDMONT/MIDLANDS OF SC. BASED ON CURRENT 88D
REGIONAL RADAR TRENDS...WITH CONVECTION MOVING INTO THE UPSTATE
AND CSRA..EXPECT ACTIVITY TO CONTINUE EASTWARD OVER THE CWA. SOME
OF THESE STORMS COULD BE STRONG AS THEY MOVE INTO THE MIDLANDS AND
CSRA THIS EVENING AND UP THROUGH MIDNIGHT. HAVE CONTINUED WITH
POPS THIS EVENING RANGING FROM 50 TO 60 PERCENT ACROSS THE CWA.
EXPECT ANOTHER MUGGY NIGHT AS TEMPERATURES ONLY FALL INTO THE
LOWER/MIDDLE 70S WITH DEWPOINTS TEMPERATURES NEAR/ARND 70.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
UPPER LEVEL TROF TO DEEPEN OVER THE AREA DURING THE WEEKEND. THE
SURFACE FRONT AND A COUPLE OF UPPER LEVEL SHORT WAVES WILL PROVIDE
A FOCUS FOR SHOWERS AND THUNDERSTORMS. DEEP SOUTHWEST FLOW ALOFT
WILL TRANSPORT MOISTURE/SEVERAL SHORT WAVE TRIGGERS AND MODERATELY
UNSTABLE AIR MASS SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS THROUGH THE WEEKEND...MAINLY DIURNAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL TROF REMAINS OVER THE AREA THROUGH MUCH OF THE WEEK.
THIS WILL CONTINUE THE PATTERN OF AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS. HOWEVER... BY THURSDAY THE TROF BEGINS TO LIFT OUT
AND HIGH PRESSURE BEGINS TO BUILD IN FROM THE MID ATLANTIC AREA
REDUCING THE CHANGE OF RAIN LATE IN THE WEEK AND INTO NEXT
WEEKEND. TEMPS WILL IN THE UPPER 80S TO LOWER 90S DURING THE DAY
AND IN THE LOWER 70S AT NIGHT.
&&
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH LATE THIS AFTERNOON. WEST TO SOUTHWEST
WINDS PROVIDING DOWNSLOPE FLOW/SUBSIDENCE. CLOUD BASES AROUND 4000
FEET WITH CIRRUS CLOUDS ABOVE.
SHOWERS AND THUNDERSTORMS EXPECTED TO TO DEVELOP LATE THIS AFTERNOON
AND EVENING AS AN UPPER LEVEL DISTURBANCE CROSSES THE REGION.
OPTIMUM PERIOD FOR CONVECTION FROM 28/23Z TO 29/06Z. HAVE INCLUDED
TEMPO GROUP IN TAFS FOR EVENING CONVECTION. THE NAM AND RUC MODELS ARE
INDICATING IFR/MVFR CIGS DEVELOPING LATE TONIGHT INTO SATURDAY
MORNING. SINCE CONFIDENCE IS LOW...HAVE NOT INCLUDED EARLY MORNING
RESTRICTIONS. THE CHANCE FOR SCATTERED CONVECTION WILL CONTINUE
ACROSS THE TAF SITES SATURDAY MORNING INTO THE AFTERNOON.
EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS POSSIBLE EACH DAY
IN MAINLY AFTERNOON/EVENING THUNDERSTORMS...AS WELL AS LATE
NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CLIMATE...
THROUGH THU JUNE 28TH...AUGUSTA GA BUSH FIELD HAS RECEIVED A
TOTAL OF 10.52 INCHES OF RAIN SO FAR FOR THE MONTH OF JUNE. THIS
HAS ALREADY ESTABLISHED JUNE 2013 AS THE 2ND WETTEST JUNE ON
RECORD AT AUGUSTA. THE WETTEST JUNE ON RECORD AT AUGUSTA IS 10.59
INCHES SET IN 2004...SO TO ESTABLISH JUNE 2013 AS THE WETTEST JUNE
ON RECORD AT AUGUSTA...AGS NEEDS TO RECEIVE 0.08 MORE INCHES OF
RAIN THIS MONTH. ALTHOUGH WE DO NOT KEEP RECORDS FOR DANIEL
FIELD...IT HAS RECEIVED 13.47 INCHES OF RAIN SO FAR FOR JUNE.
QUITE A DRAMATIC DIFFERENCE FROM LAST JUNE AS AUGUSTA BUSH FIELD
ONLY RECEIVED 2.48 INCHES FOR THE MONTH.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1121 AM EDT THU JUN 27 2013
.UPDATE...
MAIN UPDATE THIS MORNING IS TO POPS TO CATCH MORE NEAR TERM
TRENDS. HAD SOME STRONGER STORMS THIS MORNING ACROSS NE AL THAT
SHIFTED INTO NW GA THIS MORNING BUT HAVE ALSO HAD ADDITIONAL
DEVELOPMENT NORTH AND EAST OF THIS LINE. FORTUNATELY...THIS AREA
OF STRONGER STORMS HAS WEAKENED FOR NOW. OVERALL THINKING IS
TOWARD THE TRENDS OF THE HRRR. LINE OF STORMS ACROSS NORTH GEORGIA
WILL CONTINUE TO SINK SOUTHWARD INTO THE AFTERNOON BUT EXPECT BOTH
DEVELOPMENT AHEAD OF AND BEHIND THIS LINE ACROSS BOTH NORTH AND
CENTRAL GEORGIA.
MODIFIED 12Z FFC SOUNDING FOR THE EXPECTED CONDITIONS ACROSS
CENTRAL GEORGIA THIS AFTERNOON SHOWS AROUND 4000 J/KG OF CAPE...SO
EXPECTING PLENTY OF INSTABILITY THIS AFTERNOON. WITH THIS...SEVERE
STORMS ARE STILL POSSIBLE THIS AFTERNOON WITH THE MAIN THREATS
BEING DAMAGING WIND AND HAIL.
11
&&
.PREV DISCUSSION...
SHORT TERM.../TODAY AND TONIGHT/
/ISSUED 351 AM EDT THU JUN 27 2013/
OVER THE LAST FEW HOURS LARGE THUNDERSTORM COMPLEX OVER THE TN
VALLEY HAS MOVED INTO NORTHERN AL AND WESTERN NC. ONLY A FEW
SHOWERS/ISO THUNDERSTORMS HAVE MADE IT INTO NORTHERN GA. THE HRRR
HAS A VERY GOOD HANDLE ON THE SYSTEM. IR IMAGERY SHOWS COPIOUS
AMOUNTS OF CLOUD DEBRIS SPREADING INTO NORTHERN GA THIS MORNING.
IF THE CLOUD COVER HOLDS...THIS MAY HELP LIMIT INSTABILITY ACROSS
THE NORTHERN ZONES.
HRRR IS HINTING THAT THE COMPLEX WILL LAY OUT AN OUTFLOW BOUNDARY
ACROSS NORTH GA THIS MORNING. THIS SCENARIO SEEMS REASONABLE AND
EXPECT LATE MORNING/AFT THUNDERSTORMS TO FILL IN ACROSS THE SOUTHERN
TWO THIRDS OF THE FORECAST AREA AS THE ATMOS DESTABILIZES. STORMS
WILL HAVE THE POTENTIAL TO BECOME SEVERE...WITH DAMAGING WIND GUSTS
AND LARGE HAIL POSSIBLE. IN ADDITION...WITH PWATS AOA 2
INCHES...LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE. EXPECT
CONVECTION TO DIMINISH IN THE EVENING WITH THE LOSS OF HEATING.
EXACTLY WHERE CONVECTION WILL DEVELOP THIS AFTERNOON WILL HEAVILY
DEPEND UPON WHERE THE OUTFLOW BOUNDARY SETS UP. IN
ADDITION...THICKER CLOUD COVER TO THE NORTH COULD HELP LIMIT
THUNDERSTORM DEVELOPMENT.
HAVE PLACED THE HIGHEST POPS IN THE NORTH FOR THE FIRST PART OF THE
DAY. MAY HAVE TO MAKE SOME ALTERATIONS LATER THIS
MORNING...DEPENDING UPON IF ANY OF THE SHOWERS OVER NORTHERN GA MAKE
IT DOWN TO THE METRO. THE HIGHEST POPS SHOULD BE SOUTH OF THE METRO
AREA DURING THE LATE AFTERNOON AND EARLY EVENING.
NLISTEMAA
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
/ISSUED 351 AM EDT THU JUN 27 2013/
FRIDAY BEGINS WITH ONE WAVE OF SHORTWAVE ENERGY EXITING OFF THE SE
ATLANTIC COAST WHILE A SECOND SYSTEM LOOKS POISED TO DROP THROUGH
THE TENNESSEE VALLEY AND INTO THE LOCAL AREA FRIDAY AFTERNOON. AT
THIS TIME...INSTABILITY LOOKS TO BE ADEQUATE FOR NUMEROUS
THUNDERSTORMS TO DEVELOP BUT LESS THAN PREVIOUS DAYS VALUES AND
WITH LIMITED SHEAR VALUES IN PLACE...ONLY ISOLATED SEVERE STORMS
WITH THIS COMPLEX ARE EXPECTED AT THIS TIME. WITH SURFACE TROUGH
AXIS AND CONTINUED IMPULSES ROTATING THROUGH THE BASE OF THE
TROUGH...POPS WILL REMAIN HIGHER THAN CLIMO THROUGH THE OVERNIGHT
PERIOD AND HAVE REFLECTED THIS TREND IN THE LATEST GRID SET.
MAIN MOISTURE AXIS WILL SHIFT SOUTH FOR SATURDAY BUT ADDITIONAL
STRONG IMPULSE WILL MOVE ON THE DOORSTEP OF NORTH GA BY LATE
EVENING. WILL KEEP HIGHEST POPS WHERE BETTER MOISTURE IS WITH
LIKELY TO THE SOUTH BUT WILL GO HIGHER THAN GUIDANCE FOR THE NORTH
GIVEN BETTER UPPER SUPPORT.
THE ACTUAL UPPER LOW WHICH WILL HAVE BEEN A SEMI PERMANENT FEATURE
BY THIS POINT WILL FINALLY ROTATE SOUTHWARD SATURDAY NIGHT INTO
SUNDAY. AGAIN...BETTER MOISTURE REMAINS OVER EXTREME SOUTHERN
SECTIONS OF THE FORECAST AREA AND HAVE GONE LIKELY THERE AGAIN
ALTHOUGH WENT HIGHER THAN GUIDANCE NORTH AGAIN WITH UPPER LOW.
THROUGH THE REMAINDER OF THE PERIOD...UPPER LOW WEAKENS AND
RETROGRADES WITH LESS UPPER SUPPORT. DESPITE THIS...SOUTHEAST FLOW
TO BRING COPIOUS AMOUNTS OF MOISTURE TO THE AREA RESULTING IN POPS
ABOVE CLIMO. THIS WILL ALSO KEEP TEMPS BELOW CLIMO FOR THE
REMAINDER OF THE LONG TERM PERIOD AS WELL.
DEESE
AVIATION...
12Z UPDATE...
/ISSUED 734 AM EDT THU JUN 27 2013/
MADE A FEW CHANGES TO THE TAF FOR THE 12Z UPDATE. FOLLOWED THE
05Z HRRR FAIRLY CLOSELY. EXPECT EARLIER THUNDERSTORM COMPLEX
ACROSS THE TN VALLEY TO LAY DOWN AN OUTFLOW BOUNDARY LATER THIS
MORNING. CONVECTION IS EXPECTED TO FIRE ALONG THE BOUNDARY DURING
THE LATE MORNING/EARLY AFTERNOON HOURS. CONVECTIVE DEVELOPMENT
WILL DEPEND HEAVILY ON WHERE THE OUTFLOW BOUNDARY SETS UP AND ANY
DIFFERENTIAL HEATING BOUNDARIES. TAF MAY HAVE TO BE ADJUSTED AT
LATER ISSUANCES IF CONVECTION DEVELOPS BEHIND THE INITIAL OUTFLOW
BOUNDARY.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 71 94 69 / 60 50 60 60
ATLANTA 87 72 91 71 / 60 40 60 60
BLAIRSVILLE 81 67 84 64 / 30 30 60 30
CARTERSVILLE 87 71 93 68 / 60 30 60 60
COLUMBUS 90 73 94 73 / 60 50 50 60
GAINESVILLE 86 70 90 69 / 60 30 60 60
MACON 89 72 94 72 / 60 50 50 60
ROME 89 71 94 67 / 60 30 60 40
PEACHTREE CITY 87 71 93 69 / 60 50 60 60
VIDALIA 90 74 93 75 / 60 60 50 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...11
SHORT TERM...NLISTEMAA
LONG TERM....DEESE
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
351 AM EDT THU JUN 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
OVER THE LAST FEW HOURS LARGE THUNDERSTORM COMPLEX OVER THE TN
VALLEY HAS MOVED INTO NORTHERN AL AND WESTERN NC. ONLY A FEW
SHOWERS/ISO THUNDERSTORMS HAVE MADE IT INTO NORTHERN GA. THE HRRR
HAS A VERY GOOD HANDLE ON THE SYSTEM. IR IMAGERY SHOWS COPIOUS
AMOUNTS OF CLOUD DEBRIS SPREADING INTO NORTHERN GA THIS MORNING.
IF THE CLOUD COVER HOLDS...THIS MAY HELP LIMIT INSTABILITY ACROSS
THE NORTHERN ZONES.
HRRR IS HINTING THAT THE COMPLEX WILL LAY OUT AN OUTFLOW BOUNDARY
ACROSS NORTH GA THIS MORNING. THIS SCENARIO SEEMS REASONABLE AND
EXPECT LATE MORNING/AFT THUNDERSTORMS TO FILL IN ACROSS THE SOUTHERN
TWO THIRDS OF THE FORECAST AREA AS THE ATMOS DESTABILIZES. STORMS
WILL HAVE THE POTENTIAL TO BECOME SEVERE...WITH DAMAGING WIND GUSTS
AND LARGE HAIL POSSIBLE. IN ADDITION...WITH PWATS AOA 2
INCHES...LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE. EXPECT
CONVECTION TO DIMINISH IN THE EVENING WITH THE LOSS OF HEATING.
EXACTLY WHERE CONVECTION WILL DEVELOP THIS AFTERNOON WILL HEAVILY
DEPEND UPON WHERE THE OUTFLOW BOUNDARY SETS UP. IN
ADDITION...THICKER CLOUD COVER TO THE NORTH COULD HELP LIMIT
THUNDERSTORM DEVELOPMENT.
HAVE PLACED THE HIGHEST POPS IN THE NORTH FOR THE FIRST PART OF THE
DAY. MAY HAVE TO MAKE SOME ALTERATIONS LATER THIS
MORNING...DEPENDING UPON IF ANY OF THE SHOWERS OVER NORTHERN GA MAKE
IT DOWN TO THE METRO. THE HIGHEST POPS SHOULD BE SOUTH OF THE METRO
AREA DURING THE LATE AFTERNOON AND EARLY EVENING.
NLISTEMAA
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
FRIDAY BEGINS WITH ONE WAVE OF SHORTWAVE ENERGY EXITING OFF THE SE
ATLANTIC COAST WHILE A SECOND SYSTEM LOOKS POISED TO DROP THROUGH
THE TENNESSEE VALLEY AND INTO THE LOCAL AREA FRIDAY AFTERNOON. AT
THIS TIME...INSTABILITY LOOKS TO BE ADEQUATE FOR NUMEROUS
THUNDERSTORMS TO DEVELOP BUT LESS THAN PREVIOUS DAYS VALUES AND
WITH LIMITED SHEAR VALUES IN PLACE...ONLY ISOLATED SEVERE STORMS
WITH THIS COMPLEX ARE EXPECTED AT THIS TIME. WITH SURFACE TROUGH
AXIS AND CONTINUED IMPULSES ROTATING THROUGH THE BASE OF THE
TROUGH...POPS WILL REMAIN HIGHER THAN CLIMO THROUGH THE OVERNIGHT
PERIOD AND HAVE REFLECTED THIS TREND IN THE LATEST GRID SET.
MAIN MOISTURE AXIS WILL SHIFT SOUTH FOR SATURDAY BUT ADDITIONAL
STRONG IMPULSE WILL MOVE ON THE DOORSTEP OF NORTH GA BY LATE
EVENING. WILL KEEP HIGHEST POPS WHERE BETTER MOISTURE IS WITH
LIKELY TO THE SOUTH BUT WILL GO HIGHER THAN GUIDANCE FOR THE NORTH
GIVEN BETTER UPPER SUPPORT.
THE ACTUAL UPPER LOW WHICH WILL HAVE BEEN A SEMI PERMANENT FEATURE
BY THIS POINT WILL FINALLY ROTATE SOUTHWARD SATURDAY NIGHT INTO
SUNDAY. AGAIN...BETTER MOISTURE REMAINS OVER EXTREME SOUTHERN
SECTIONS OF THE FORECAST AREA AND HAVE GONE LIKELY THERE AGAIN
ALTHOUGH WENT HIGHER THAN GUIDANCE NORTH AGAIN WITH UPPER LOW.
THROUGH THE REMAINDER OF THE PERIOD...UPPER LOW WEAKENS AND
RETROGRADES WITH LESS UPPER SUPPORT. DESPITE THIS...SOUTHEAST FLOW
TO BRING COPIOUS AMOUNTS OF MOISTURE TO THE AREA RESULTING IN POPS
ABOVE CLIMO. THIS WILL ALSO KEEP TEMPS BELOW CLIMO FOR THE
REMAINDER OF THE LONG TERM PERIOD AS WELL.
DEESE
&&
.PREV DISCUSSION... /ISSUED 145 AM EDT THU JUN 27 2013/
PREV DISCUSSION... /ISSUED 1020 PM EDT WED JUN 26 2013/
UPDATE...
HAVE REMOVED POPS FOR THE NIGHT EXCEPT FOR THE NORTHERN ZONES. THE
THUNDERSTORM COMPLEX MOVING SOUTH THROUGH KENTUCKY STILL EXPECTED TO
AFFECT NORTH GA BEFORE SUNRISE IF IT HOLDS TOGETHER.
41
PREVIOUS...
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
WITH NORTHWEST FLOW ALOFT...EXPECT RIPPLES IN THE FLOW TO CONTINUE
ENHANCING THUNDERSTORMS THE REST OF TODAY. SCATTERED THUNDERSTORMS
ARE POSSIBLE ACROSS NORTH AND EAST CENTRAL GEORGIA THE REST OF TODAY
AND INTO TONIGHT. THE MAIN CONCERN IN THE SHORT TERM IS THE
POSSIBLE DEVELOPMENT OF A MCS ACROSS THE OHIO RIVER VALLEY TONIGHT.
06Z AND 12Z GFS SUGGEST ANYWHERE FROM 25 TO 35 KNOTS OF 0-6 KM SHEAR
ACROSS NORTH AND WEST CENTRAL GEORGIA LATE TONIGHT AND INTO THE AM
TOMORROW. WITH ABUNDANT LOW LEVEL MOISTURE...HIRES MODELS HAVE
CONSISTENTLY PREDICTED A MCS THAT FORMS OVER SOUTHERN INDIANA AND
THEN DIVES SOUTH INTO MISSISSIPPI AND ALABAMA OVERNIGHT. THE SPC
HAS INTRODUCED NORTH GEORGIA INTO A SLIGHT RISK FOR SEVERE WEATHER
TODAY AND TONIGHT. THERE ARE A FEW POSSIBLE SCENARIOS WITH THE
POTENTIAL MCS.
1. NO MCS FORMS. THESE SEEMS UNLIKELY AS CONVECTION IS ALREADY
ONGOING IN SOUTHERN INDIANA. THE CURRENT MOTION OF THE MCS IS TO
THE EAST AND WOULD LIKELY STAY NORTH OF OUR AREA...UNLESS THE
HIRES MODELS ARE CORRECT AND THEN IT COULD DIVE SOUTH INTO OUR
AREA.
2. THE MCS FORMS FURTHER TO THE SOUTH AND WEST...IN THIS CASE THE
FLOW WOULD SUGGEST THAT A MCS WOULD MOVE THROUGH TENNESSEE AND
KENTUCKY OVERNIGHT AND INTO THE AM AND THEN MOVE IN NORTH GEORGIA
AROUND THE MORNING RUSH HOUR.
3. THE HIRES MODELS ARE RIGHT AND STORMS FORM OVER MO AND DIVE
SOUTH INTO MISSISSIPPI AND ALABAMA. IN THIS CASE WE WOULD SEE OUR
FAR WESTERN COUNTIES EXPERIENCE PART OF THE MCS IN THE AM.
BELIEVE THAT ONE OF THE LATTER TWO POSSIBILITIES WILL BE
POSSIBLE. AS SUCH...INTRODUCED LIKELY POPS ACROSS THE CWA FOR
TOMORROW. MAIN THREAT TOMORROW WITH ANY THUNDERSTORMS ARE STRONG
TO SEVERE WIND GUSTS. AN ISOLATED WEAK TORNADO CANNOT BE RULED
OUT.
AS THE REMNANTS OF A MCS MOVES SOUTH THROUGH THE DAY...THE
DEVELOPMENT OF SCATTERED THUNDERSTORMS SEEMS LIKELY ACROSS SOUTHERN
GEORGIA DURING THE AFTERNOON. SOME OF THESE STORMS COULD ALSO BE
STRONG. DEPENDING ON THE SPEED OF THE MCS...WE COULD GET ENOUGH
HEATING TOMORROW FOR THUNDERSTORMS TO REFORM ACROSS NORTH GEORGIA
AS WELL.
ARG
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MAIN ADJUSTMENT TO LONG TERM WAS TO LOWER POPS ACROSS PORTIONS OF
THE NORTH ON SATURDAY BASED ON PROGGED MOISTURE/FORCING IN RECENT
GUIDANCE AND OTHER OFFICE COLLABORATION. OTHERWISE ONLY MINOR
OTHER ADJUSTMENTS MADE AND FORECAST LOOKS TO BE GENERALLY ON
TRACK. PREVIOUS DISCUSSION FOLLOWS...
BAKER
PREV DISCUSSION... /ISSUED 416 AM EDT WED JUN 26 2013/
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
LONG TERM PERIOD BEGINS WITH FIRST SHORTWAVE EXITING TO THE
SOUTHEAST BUT ANOTHER RIGHT ON ITS HEELS FOR FRIDAY MORNING WITH
PERTURBATIONS IN MEAN TROUGH FLOW ALLOWING FOR ROBUST CONVECTIVE
DEVELOPMENT OVER NORTHERN SECTIONS OF THE FORECAST AREA. GFS
ACTUALLY CARRIES AN ADDITIONAL EAVE INTO NORTH GA LATE FRIDAY
AFTERNOON RESULTING IN MULTIPLE ROUNDS OF CONVECTION. ECMWF NOT AS
AGGRESSIVE IN GENERATING THE SHORTWAVES IN THE MEAN FLOW BUT STILL
GENERATES AND SINGLE WAVE OF ENHANCED PRECIP CHANCES FOR NORTH GA
FRIDAY AFTERNOON.
GFS SHOWS MAIN WAVE PUSHING THROUGH THE FORECAST AREA THROUGH SAT
AFTERNOON WITH POPS DECREASING TO JUST SLIGHT CHANCE FOR THE NORTH
BUT STILL CLOSE TO LOW END LIKELY FOR THE SOUTH. RESPITE LOOKS TO
BE SHORTLIVED FOR THE NORTHERN HALF HOWEVER AS STRONG SPOKE OF
MEAN TROUGH ROTATES THROUGH AND SURGES PRECIP BACK INTO THE AREA
FROM THE SW AND WILL ADJUST POPS ACCORDINGLY.
FOR THE REMAINDER OF THE PERIOD...AREA TRANSITIONS FROM EAST SIDE
OF UPPER RIDGE TO BEING MORE INFLUENCED BY THE THROUGH ITSELF. GFS
INDICATES POTENT WAVES ALONG THE TROUGH AND SHOULD SEE CONTINUED
ELEVATED CHANCE OF THUNDERSTORMS THROUGH THE REMAINDER OF THE LONG
TERM PERIOD.
DEESE
.AVIATION...
06Z UPDATE...
THUNDERSTORM TIMING WILL BE THE FORECAST ISSUE OF THE DAY. COMPLEX
OVER THE TN VALLEY IS PROGGED BY THE HRRR TO WEAKEN AS IT
APPROACHES NORTHERN GA AND PRODUCE AN OUTFLOW BOUNDARY THAT
CONVECTION WILL LIKELY FIRE UPON LATER THIS AFTERNOON. LOOKS LIKE
THE BEST TIMING OF STORMS AT ATL WOULD BE BETWEEN 13Z AND 16Z.
HOWEVER...MAY HAVE TO EXAMINE MODELS FURTHER IN CASE COMPLEX
DOESN`T STABILIZE THE ATMOS AND THE POTENTIAL FOR STORMS CONTINUE
IN THE AFT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
NLISTEMAA
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 71 96 69 / 60 50 40 60
ATLANTA 87 72 93 71 / 60 40 40 60
BLAIRSVILLE 81 67 86 64 / 60 30 60 30
CARTERSVILLE 87 71 95 68 / 60 30 60 60
COLUMBUS 90 73 96 73 / 60 50 40 60
GAINESVILLE 86 70 92 69 / 60 30 50 60
MACON 89 72 96 72 / 60 50 30 60
ROME 89 71 96 67 / 60 30 60 40
PEACHTREE CITY 87 71 95 69 / 60 50 40 60
VIDALIA 90 74 95 75 / 60 60 50 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NLISTEMAA
LONG TERM....DEESE
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
145 AM EDT THU JUN 27 2013
.PREV DISCUSSION... /ISSUED 1020 PM EDT WED JUN 26 2013/
UPDATE...
HAVE REMOVED POPS FOR THE NIGHT EXCEPT FOR THE NORTHERN ZONES. THE
THUNDERSTORM COMPLEX MOVING SOUTH THROUGH KENTUCKY STILL EXPECTED TO
AFFECT NORTH GA BEFORE SUNRISE IF IT HOLDS TOGETHER.
41
PREVIOUS...
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
WITH NORTHWEST FLOW ALOFT...EXPECT RIPPLES IN THE FLOW TO CONTINUE
ENHANCING THUNDERSTORMS THE REST OF TODAY. SCATTERED THUNDERSTORMS
ARE POSSIBLE ACROSS NORTH AND EAST CENTRAL GEORGIA THE REST OF TODAY
AND INTO TONIGHT. THE MAIN CONCERN IN THE SHORT TERM IS THE
POSSIBLE DEVELOPMENT OF A MCS ACROSS THE OHIO RIVER VALLEY TONIGHT.
06Z AND 12Z GFS SUGGEST ANYWHERE FROM 25 TO 35 KNOTS OF 0-6 KM SHEAR
ACROSS NORTH AND WEST CENTRAL GEORGIA LATE TONIGHT AND INTO THE AM
TOMORROW. WITH ABUNDANT LOW LEVEL MOISTURE...HIRES MODELS HAVE
CONSISTENTLY PREDICTED A MCS THAT FORMS OVER SOUTHERN INDIANA AND
THEN DIVES SOUTH INTO MISSISSIPPI AND ALABAMA OVERNIGHT. THE SPC
HAS INTRODUCED NORTH GEORGIA INTO A SLIGHT RISK FOR SEVERE WEATHER
TODAY AND TONIGHT. THERE ARE A FEW POSSIBLE SCENARIOS WITH THE
POTENTIAL MCS.
1. NO MCS FORMS. THESE SEEMS UNLIKELY AS CONVECTION IS ALREADY
ONGOING IN SOUTHERN INDIANA. THE CURRENT MOTION OF THE MCS IS TO
THE EAST AND WOULD LIKELY STAY NORTH OF OUR AREA...UNLESS THE
HIRES MODELS ARE CORRECT AND THEN IT COULD DIVE SOUTH INTO OUR
AREA.
2. THE MCS FORMS FURTHER TO THE SOUTH AND WEST...IN THIS CASE THE
FLOW WOULD SUGGEST THAT A MCS WOULD MOVE THROUGH TENNESSEE AND
KENTUCKY OVERNIGHT AND INTO THE AM AND THEN MOVE IN NORTH GEORGIA
AROUND THE MORNING RUSH HOUR.
3. THE HIRES MODELS ARE RIGHT AND STORMS FORM OVER MO AND DIVE
SOUTH INTO MISSISSIPPI AND ALABAMA. IN THIS CASE WE WOULD SEE OUR
FAR WESTERN COUNTIES EXPERIENCE PART OF THE MCS IN THE AM.
BELIEVE THAT ONE OF THE LATTER TWO POSSIBILITIES WILL BE
POSSIBLE. AS SUCH...INTRODUCED LIKELY POPS ACROSS THE CWA FOR
TOMORROW. MAIN THREAT TOMORROW WITH ANY THUNDERSTORMS ARE STRONG
TO SEVERE WIND GUSTS. AN ISOLATED WEAK TORNADO CANNOT BE RULED
OUT.
AS THE REMNANTS OF A MCS MOVES SOUTH THROUGH THE DAY...THE
DEVELOPMENT OF SCATTERED THUNDERSTORMS SEEMS LIKELY ACROSS SOUTHERN
GEORGIA DURING THE AFTERNOON. SOME OF THESE STORMS COULD ALSO BE
STRONG. DEPENDING ON THE SPEED OF THE MCS...WE COULD GET ENOUGH
HEATING TOMORROW FOR THUNDERSTORMS TO REFORM ACROSS NORTH GEORGIA
AS WELL.
ARG
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MAIN ADJUSTMENT TO LONG TERM WAS TO LOWER POPS ACROSS PORTIONS OF
THE NORTH ON SATURDAY BASED ON PROGGED MOISTURE/FORCING IN RECENT
GUIDANCE AND OTHER OFFICE COLLABORATION. OTHERWISE ONLY MINOR
OTHER ADJUSTMENTS MADE AND FORECAST LOOKS TO BE GENERALLY ON
TRACK. PREVIOUS DISCUSSION FOLLOWS...
BAKER
PREV DISCUSSION... /ISSUED 416 AM EDT WED JUN 26 2013/
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
LONG TERM PERIOD BEGINS WITH FIRST SHORTWAVE EXITING TO THE
SOUTHEAST BUT ANOTHER RIGHT ON ITS HEELS FOR FRIDAY MORNING WITH
PERTURBATIONS IN MEAN TROUGH FLOW ALLOWING FOR ROBUST CONVECTIVE
DEVELOPMENT OVER NORTHERN SECTIONS OF THE FORECAST AREA. GFS
ACTUALLY CARRIES AN ADDITIONAL EAVE INTO NORTH GA LATE FRIDAY
AFTERNOON RESULTING IN MULTIPLE ROUNDS OF CONVECTION. ECMWF NOT AS
AGGRESSIVE IN GENERATING THE SHORTWAVES IN THE MEAN FLOW BUT STILL
GENERATES AND SINGLE WAVE OF ENHANCED PRECIP CHANCES FOR NORTH GA
FRIDAY AFTERNOON.
GFS SHOWS MAIN WAVE PUSHING THROUGH THE FORECAST AREA THROUGH SAT
AFTERNOON WITH POPS DECREASING TO JUST SLIGHT CHANCE FOR THE NORTH
BUT STILL CLOSE TO LOW END LIKELY FOR THE SOUTH. RESPITE LOOKS TO
BE SHORTLIVED FOR THE NORTHERN HALF HOWEVER AS STRONG SPOKE OF
MEAN TROUGH ROTATES THROUGH AND SURGES PRECIP BACK INTO THE AREA
FROM THE SW AND WILL ADJUST POPS ACCORDINGLY.
FOR THE REMAINDER OF THE PERIOD...AREA TRANSITIONS FROM EAST SIDE
OF UPPER RIDGE TO BEING MORE INFLUENCED BY THE THROUGH ITSELF. GFS
INDICATES POTENT WAVES ALONG THE TROUGH AND SHOULD SEE CONTINUED
ELEVATED CHANCE OF THUNDERSTORMS THROUGH THE REMAINDER OF THE LONG
TERM PERIOD.
DEESE
&&
.AVIATION...
06Z UPDATE...
THUNDERSTORM TIMING WILL BE THE FORECAST ISSUE OF THE DAY. COMPLEX
OVER THE TN VALLEY IS PROGGED BY THE HRRR TO WEAKEN AS IT
APPROACHES NORTHERN GA AND PRODUCE AN OUTFLOW BOUNDARY THAT
CONVECTION WILL LIKELY FIRE UPON LATER THIS AFTERNOON. LOOKS LIKE
THE BEST TIMING OF STORMS AT ATL WOULD BE BETWEEN 13Z AND 16Z.
HOWEVER...MAY HAVE TO EXAMINE MODELS FURTHER IN CASE COMPLEX
DOESN`T STABILIZE THE ATMOS AND THE POTENTIAL FOR STORMS CONTINUE
IN THE AFT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
NLISTEMAA
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 71 92 69 / 60 50 40 60
ATLANTA 87 72 91 70 / 60 40 40 60
BLAIRSVILLE 82 67 88 65 / 60 30 60 30
CARTERSVILLE 87 70 94 69 / 60 30 60 60
COLUMBUS 90 74 94 73 / 60 50 40 60
GAINESVILLE 86 71 92 69 / 60 30 50 60
MACON 89 72 93 72 / 60 50 30 60
ROME 89 70 96 69 / 60 30 60 40
PEACHTREE CITY 87 70 90 70 / 60 50 40 60
VIDALIA 92 74 91 74 / 60 60 50 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
532 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...
528 PM CDT
SUPERCELLULAR STORM CAPABLE OF GUSTY WINDS AND POSSIBLY SOME HAIL
HEADED ACROSS NORTHWEST METRO AND POTENTIALLY TO CHICAGO.
SCATTERED CONVECTION CONTINUES TO DEVELOP AHEAD OF SHEARED
SHORTWAVE MOVING SOUTHEAST ACROSS SOUTHERN WI. SEVERAL CELLS HAVE
HAD A MODE OF SUPERCELLULAR INCLUDING AT LEAST ONE SPLIT IN THE
CWA. UPDRAFTS HAVE BEEN QUICKLY DEVELOPING AND MOST RECENT STORM
OVER NORTHWEST COOK COUNTY IS EXHIBITING ROTATION AND A WEAK ECHO
REGION...SIGNS IT IS LIKELY TO PERSIST FOR A WHILE. SEVERE WIND
GUSTS LOOK TO BE THE GREATEST THREAT WITH THIS WITH STRONG
DOWNDRAFT POTENTIAL. THERE HAVE ALREADY SEEN A FEW MESONET SITES
GUST IN EXCESS OF 40 MPH...INCLUDING 47 MPH AT ALGONQUIN AND LAKE IN
THE HILLS WHEN THE STORM LOOKED LESS INTENSE THAN NOW. WHILE THERE
IS ROTATION AT SOME LOWER ANGLES ON RADAR...IT BECOMES WEAKER TOWARD
THE LOW-LEVELS AND THE ENVIRONMENT CONTINUES TO NOT BE FAVORABLE FOR
TORNADOES WITH LIMITED LOW-LEVEL FOCUS. HAIL TO QUARTER SIZE OR
LARGER LOOK TO BE PRETTY ISOLATED BUT POSSIBLE UNDER THE HEART OF
THE STORM.
MTF/IZZI
.MESOSCALE DISCUSSION...
1216 PM CDT
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
248 PM CDT
THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES
DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR
IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR
MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND
EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE.
THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE
LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE
AREA WITH DECREASING CLOUDINESS.
WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING
RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN
UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH
MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE
WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD
ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY
LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN
ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH
THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS
AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER
MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE
AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE
VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND
LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS
WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL.
PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH
THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4
INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED
HEAVIER SHOWERS.
THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER
GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS
OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW
THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK.
THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY
NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN
SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY
MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND
THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE
END OF THE PERIOD.
THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW
AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN
TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT
ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE
LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED
AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF
YEAR.
ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE
FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6
FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE
SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* TSRA THROUGH 01Z.
* LAKE BREEZE/OUTFLOW REACHING ORD/MDW BETWEEN 00Z-01Z...SHIFTING
WESTERLY WINDS NORTHEAST. CMS
//DISCUSSION...UPDATED 22Z...
TSRA MOVING ACROSS NORTHEAST IL AND WILL CONTINUE EAST/SOUTHEAST
OVER THE NEXT FEW HOURS WITH ADDITIONAL DEVELOPMENT POSSIBLE
THROUGH SUNSET. CONVECTIVE WIND/OUTFLOW OVER NORTHWEST COOK COUNTY
WILL BE PUSHING THROUGH ORD IN THE NEXT 20 MINUTES WITH GUSTS
35-40 KTS POSSIBLE. LAKE BREEZE/OUTFLOW FROM CONVECTION ACROSS
SOUTHEAST WI MOVING SOUTH THROUGH NORTHERN LAKE COUNTY IL. THIS
WILL MOVE SOUTH ACROSS THE CHICAGO AREA TERMINALS OVER THE NEXT
FEW HRS SHIFTING WINDS NORTH/NORTHEAST. ADDITIONAL THUNDERSTORMS
MAY SPEED THIS BOUNDARY UP AND REFINEMENT TO CURRENT TIMING CAN BE
EXPECTED. CMS
PREVIOUS 18Z DISCUSSION...
THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER
CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE
ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE
SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A
LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL
DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE
AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE
WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW
ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM.
OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND
CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING
THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE
BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION
OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL
LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE
TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY
PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB
DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO
ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL
FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT
IMPACTS ON THE TERMINALS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH FOR TSRA THROUGH EARLY EVENING.
* HIGH FOR WIND SHIFT LATE AFTERNOON/EARLY EVENING...MEDIUM FOR
TIMING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
238 PM CDT
AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY
SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY
LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY.
INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED
OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE
LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD
BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS
ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME
DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING
THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH
POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING
WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE
OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT.
WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT
ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
513 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...
1216 PM CDT
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
248 PM CDT
THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES
DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR
IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR
MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND
EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE.
THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE
LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE
AREA WITH DECREASING CLOUDINESS.
WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING
RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN
UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH
MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE
WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD
ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY
LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN
ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH
THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS
AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER
MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE
AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE
VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND
LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS
WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL.
PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH
THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4
INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED
HEAVIER SHOWERS.
THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER
GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS
OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW
THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK.
THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY
NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN
SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY
MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND
THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE
END OF THE PERIOD.
THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW
AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN
TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT
ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE
LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED
AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF
YEAR.
ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE
FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6
FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE
SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* TSRA THROUGH 01Z.
* LAKE BREEZE/OUTFLOW REACHING ORD/MDW BETWEEN 00Z-01Z...SHIFTING
WESTERLY WINDS NORTHEAST. CMS
//DISCUSSION...UPDATED 22Z...
TSRA MOVING ACROSS NORTHEAST IL AND WILL CONTINUE EAST/SOUTHEAST
OVER THE NEXT FEW HOURS WITH ADDITIONAL DEVELOPMENT POSSIBLE
THROUGH SUNSET. CONVECTIVE WIND/OUTFLOW OVER NORTHWEST COOK COUNTY
WILL BE PUSHING THROUGH ORD IN THE NEXT 20 MINUTES WITH GUSTS
35-40 KTS POSSIBLE. LAKE BREEZE/OUTFLOW FROM CONVECTION ACROSS
SOUTHEAST WI MOVING SOUTH THROUGH NORTHERN LAKE COUNTY IL. THIS
WILL MOVE SOUTH ACROSS THE CHICAGO AREA TERMINALS OVER THE NEXT
FEW HRS SHIFTING WINDS NORTH/NORTHEAST. ADDITIONAL THUNDERSTORMS
MAY SPEED THIS BOUNDARY UP AND REFINEMENT TO CURRENT TIMING CAN BE
EXPECTED. CMS
PREVIOUS 18Z DISCUSSION...
THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER
CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE
ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE
SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A
LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL
DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE
AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE
WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW
ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM.
OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND
CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING
THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE
BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION
OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL
LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE
TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY
PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB
DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO
ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL
FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT
IMPACTS ON THE TERMINALS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH FOR TSRA THROUGH EARLY EVENING.
* HIGH FOR WIND SHIFT LATE AFTERNOON/EARLY EVENING...MEDIUM FOR
TIMING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
238 PM CDT
AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY
SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY
LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY.
INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED
OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE
LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD
BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS
ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME
DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING
THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH
POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING
WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE
OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT.
WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT
ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
305 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...141 PM CDT
CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF
MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS
INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI
SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY
SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND
IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR
THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD
POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS
CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD
EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID
LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS
SPREADING INTO WESTERN ILLINOIS.
IZZI
1216 PM CDT...
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
248 PM CDT
THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES
DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR
IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR
MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND
EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE.
THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE
LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE
AREA WITH DECREASING CLOUDINESS.
WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING
RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN
UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH
MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE
WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD
ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY
LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN
ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH
THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS
AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER
MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE
AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE
VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND
LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS
WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL.
PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH
THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4
INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED
HEAVIER SHOWERS.
THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER
GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS
OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW
THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK.
THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY
NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN
SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY
MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND
THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE
END OF THE PERIOD.
THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW
AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN
TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT
ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE
LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED
AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF
YEAR.
ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE
FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6
FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE
SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING.
* EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER
CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE
ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE
SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A
LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL
DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE
AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE
WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW
ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM.
OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND
CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING
THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE
BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION
OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL
LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE
TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY
PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB
DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO
ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL
FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT
IMPACTS ON THE TERMINALS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING
AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED
COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* HIGH CONFIDENCE THAT LAKE BREEZE WILL REMAIN EAST OF THE
TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
238 PM CDT
AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY
SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY
LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY.
INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED
OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE
LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD
BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS
ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME
DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING
THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH
POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING
WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE
OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT.
WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT
ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
252 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...
141 PM CDT
CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF
MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS
INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI
SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY
SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND
IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR
THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD
POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS
CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD
EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID
LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS
SPREADING INTO WESTERN ILLINOIS.
IZZI
1216 PM CDT...
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
248 PM CDT
THE MAIN WEATHER CONCERNS WILL BE SHOWER AND THUNDERSTORMS CHANCES
DURING THE PERIOD. CURRENTLY...REGIONAL SATELLITE AND RADAR
IMAGERY INDICATE CONVECTION ALREADY FIRING ACROSS WISCONSIN. FOR
MORE INFORMATION ON THE SEVERE CONVECTION THIS AFTERNOON AND
EVENING PLEASE REFERENCE THE MESOSCALE DISCUSSIONS ABOVE.
THE SEVERE CONVECTION SHOULD ABATE QUICKLY THIS EVENING WITH THE
LOSS OF DAYTIME HEATING. THIS SHOULD SET UP A QUIET NIGHT ACROSS THE
AREA WITH DECREASING CLOUDINESS.
WITH THE LARGER SCALE WEATHER PATTERN FEATURING A STRONG BUILDING
RIDGE ACROSS WESTERN CONUS...THIS WILL CONTINUE TO FAVOR AN
UNSETTLED...BUT COOL NORTHWESTERLY PATTERN ACROSS THE REGION THROUGH
MUCH OF THE PERIOD. A STOUT MID LEVEL WAVE...CURRENTLY NOTED IN THE
WATER VAPOR IMAGERY ACROSS MANITOBA...IS EXPECTED TO DIG SOUTHWARD
ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO NORTHERN ILLINOIS BY
LATE FRIDAY. THIS FEATURE WILL LIKELY SPARK OFF MORE SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS WISCONSIN AND EVENTUALLY NORTHERN
ILLINOIS DURING THE AFTERNOON AS THE INCREASED ASCENT INTERACTS WITH
THE AFTERNOON INSTABILITY. HOWEVER...UNLIKE THE STORMS EXPECTED THIS
AFTERNOON...THESE DO NOT APPEAR TO POSS A SEVERE RISK. THE STRONGER
MID LEVEL FLOW IS EXPECTED TO SHIFT TO THE WEST AND SOUTH OF THE
AREA...RESULTING IN WEAKER DEEP LEVEL SHEAR. ADDITIONALLY...MLCAPE
VALUES WILL TAKE A BIG HIT TOMORROW DUE TO COOLER TEMPERATURES AND
LOWER DEW POINTS. THE ONLY THREAT FROM THESE SHOWERS AND STORMS
WILL BE THE POTENTIAL FOR SOME LOCALLY MODERATE RAINFALL.
PRECIPITABLE WATER VALUES WILL BE ON THE DECREASE ON FRIDAY WITH
THE COOLER LESS HUMID AIRMASS. HOWEVER...PWAT VALUES OF 1.3 TO 1.4
INCHES COULD STILL RESULT IN A LOW END THREAT FOR SOME ISOLATED
HEAVIER SHOWERS.
THIS WAVE IS EXPECTED TO DIG INTO A CLOSED SYSTEM ACROSS THE LOWER
GREAT LAKES AND OHIO VALLEY REGION DURING THE WEEKEND. ONCE THIS
OCCURS...THE HIGHLY AMPLIFIED FLOW ACROSS NORTH AMERICA WILL ALLOW
THIS SYSTEM TO BECOME LOCKED IN PLACE FOR A FEW DAYS INTO NEXT WEEK.
THEREFORE...THE GENERAL WEATHER FORECAST THIS WEEKEND THROUGH EARLY
NEXT WEEK IS FAVORING CONTINUED CHANCES FOR MAINLY DIURNALLY DRIVEN
SHOWERS AND SOME ISOLATED STORMS...ESPECIALLY SOUTH. HOWEVER...BY
MID WEEK...THE SYSTEM LOOKS TO TRY TO WAVER BACK TO THE NORTH...AND
THIS WOULD FAVOR CHANCES FOR SHOWERS/STORMS AREA-WIDE TOWARDS THE
END OF THE PERIOD.
THIS GENERAL WEATHER PATTERN WILL ALSO FAVOR BELOW TO MUCH BELOW
AVERAGE TEMPERATURES FOR THE FIRST PART OF JULY...WHEN
TEMPERATURES WILL LIKELY ONLY TOP OUT IN THE MID 70S. PERSISTENT
ONSHORE FLOW WILL LIKELY EVEN FAVOR UPPER 60S TO LOW 70S ON THE
LAKESHORE. A SLOW MODERATING IN TEMPS BACK TO NEAR 80 IS EXPECTED
AROUND THE 4TH OF JULY...BUT STILL BELOW AVERAGE FOR THIS TIME OF
YEAR.
ON A BEACH NOTE...STEADY NORTHERLY WINDS OF 15 TO 25 MPH DOWN THE
FETCH OF LAKE MI THIS WEEKEND WILL PRESENT BUILDING WAVES TO 3 TO 6
FT...ESPECIALLY FROM CHICAGO SOUTHEASTWARD. THIS WILL LIKELY CAUSE
SWIMMING HAZARD CONCERNS FOR A PORTION OF THE WEEKEND.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING.
* EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER
CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE
ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE
SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A
LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL
DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE
AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE
WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW
ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM.
OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND
CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING
THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE
BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION
OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL
LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE
TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY
PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB
DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO
ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL
FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT
IMPACTS ON THE TERMINALS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING
AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED
COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
238 PM CDT
AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY
SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY
LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY.
INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED
OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE
LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD
BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS
ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME
DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING
THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH
POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING
WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE
OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT.
WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT
ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
245 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...
141 PM CDT
CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF
MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS
INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI
SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY
SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND
IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR
THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD
POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS
CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD
EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID
LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS
SPREADING INTO WESTERN ILLINOIS.
IZZI
1216 PM CDT...
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING.
* EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER
CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE
ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE
SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A
LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL
DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE
AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE
WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW
ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM.
OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND
CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING
THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE
BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION
OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL
LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE
TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY
PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB
DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO
ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL
FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT
IMPACTS ON THE TERMINALS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING
AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED
COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
238 PM CDT
AS LOW PRESSURE DEVELOPS TO THE EAST FRIDAY AND MEANDERS SLOWLY
SOUTH FOR A COUPLE DAYS...NORTHWEST FLOW WILL ENVELOP THE LAKE BY
LATE TONIGHT AND TURN NORTHERLY AFTER A COLD FRONT ON FRIDAY.
INITIALLY THIS EVENING...SCATTERED SHOWERS AND STORMS ARE EXPECTED
OVER THE LAKE. WHILE THERE IS A PRONOUNCED STABLE MARINE
LAYER...THIS IS SHALLOW AND THE ATMOSPHERE BETWEEN THIS AND CLOUD
BASE IS FAVORABLE FOR STRONGER DOWNDRAFTS. SO SOME GUSTY OUTFLOWS
ARE EXPECTED FROM THESE STORMS WHICH MAY TRAVERSE QUITE SOME
DISTANCE FROM THE PARENT STORMS. THE LAKE BREEZE IN PLACE HUGGING
THE IL AND IN SHORES SHOULD DISSIPATE BY 5 TO 7 PM...WITH
POSSIBLY SOME VARIABILITY DUE TO OUTFLOWS...BEFORE TURNING
WESTERLY. FROM FRIDAY INTO SATURDAY THE NORTHERLY WINDS OVER THE
OPEN WATERS WILL BE NEAR 20 KT WITH POSSIBLY SOME GUSTS TO 25 KT.
WITH THIS WIND DIRECTION WAVES SHOULD BUILD TO NEAR SMALL CRAFT
ADVISORY CRITERIA ALONG THE IL AND IN SHORES THIS WEEKEND.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
142 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...
141 PM CDT
CONVECTIVE INITIATION IS UNDER WAY OVER WISCONSIN JUST NORTH OF
MADISON. VISIBLE SATELLITE IMAGERY SHOWS THAT THIS CONVECTION IS
INITIATING WITHIN A REGION OF ENHANCED CUMULUS THAT ARCS FROM NW WI
SOUTH INTO SOUTHWEST WI AND EXTREME NE IA. RECENT SATELLITE IMAGERY
SHOWS THAT THIS CU FIELD HAS BEEN DEVELOPING SOUTHWARD WITH TIME AND
IS BEGINNING TO EXTEND SOUTH INTO EXTREME NW IL...SO WOULD APPEAR
THAT THE MOST IMMINENT THREAT OF CONVECTIVE DEVELOPMENT THAT COULD
POSE A RISK IN OUR CWA WOULD BE FROM THE SOUTHERN EXTENT OF THIS
CUMULUS FIELD DOWN TO NEAR DBQ. STARTING TO LOOK LIKE THE SOUTHWARD
EXTENT OF THE CONVECTION COULD BE LIMITED BY THE LARGE SHIELD OF MID
LEVEL CLOUDINESS ON THE NORTHEASTERN EXTENTS OF THE MO MCS THAT IS
SPREADING INTO WESTERN ILLINOIS.
IZZI
1216 PM CDT...
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING.
* EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER
CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE
ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE
SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A
LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL
DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE
AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE
WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW
ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM.
OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND
CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING
THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE
BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION
OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL
LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE
TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY
PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB
DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO
ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL
FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT
IMPACTS ON THE TERMINALS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING
AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED
COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
304 AM CDT
EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND
REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND
THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE
SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE
EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY
GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF
HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL
FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND.
WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY
TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE
WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY
THROUGH SUNDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1235 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...1216 PM CDT
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CHANCE OF SCATTERED THUNDERSTORMS THIS AFTERNOON/EVENING.
* EXTENT THAT LAKE BREEZE WILL PUSH INLAND THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
THE PRIMARY CONCERN THIS AFTERNOON AND EVENING WILL BE ANOTHER
CHANCE FOR SCATTERED THUNDERSTORMS. WITH DAYTIME HEATING...THE
ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE. LATEST VISIBLE
SATELLITE IMAGERY SHOWS SOME CU DEVELOPMENT OVER THE AREA...BUT A
LOOK OUT THE WINDOW SHOWS THAT THERE IS NOT MUCH VERTICAL
DEVELOPMENT JUST YET...BUT AS WE GET FURTHER INTO THE
AFTERNOON...EXPECT THAT INSTABILITY WILL CONTINUE TO INCREASE
WHILE A MID LEVEL IMPULSE DROPS SEWD THROUGH THE FAST NWLY FLOW
ALOFT. SINCE THERE IS NO LARGER SCALE SURFACE FOCUSING MECHANISM.
OVER THE AREA...ANY TSRA ACTIVITY SHOULD BE SCATTERED AND
CONFIDENCE IN NAILING DOWN A TIME/DURATION OF ANY TSRA IMPACTING
THE TERMINALS. HOWEVER...RADAR IMAGERY HAS SHOWN A LAKE BREEZE
BOUNDARY PUSHING INLAND LATE THIS MORNING...BUT INLAND PROGRESSION
OF THE BOUNDARY HAS SIGNIFICANTLY SLOWED AND FEEL THAT IT WILL
LIKELY REMAIN EAST OF THE TERMINALS. WHILE WIND DIRECTION AT THE
TERMINALS SHOULD NOT BE IMPACTED BY A LAKE BREEZE PASSAGE...IT MAY
PROVIDE ENOUGH SURFACE FORCING TO GENERATE TOWERING CU OR CB
DEVELOPMENT...AND ULTIMATELY...SOME THUNDERSTORMS...IN ADDITION TO
ANY OTHER SCATTERED THUNDERSTORM DEVELOPMENT. SINCE UPPER LEVEL
FLOW IS RATHER FAST...ANY THUNDERSTORMS SHOULD ONLY HAVE SHORT
IMPACTS ON THE TERMINALS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN SCATTERED THUNDERSTORMS DEVELOPING
AT SOME POINT THIS AFTERNOON AND EVENING...BUT DUE TO SCATTERED
COVERAGE...LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
304 AM CDT
EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND
REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND
THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE
SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE
EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY
GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF
HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL
FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND.
WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY
TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE
WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY
THROUGH SUNDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1216 PM CDT THU JUN 27 2013
.MESOSCALE DISCUSSION...
1216 PM CDT
STRONG SUMMER TIME JET STREAM DIVING INTO THE UPPER MS VALLEY TODAY
WITH MORNING U/A ANALYSIS SHOWING NEARLY 100KT WINDS FROM BIS
SOUTHEAST TO MPX ALONG THE AXIS OF THIS JET. WEAK SURFACE FRONT
MOVED THROUGH THE REGION ALREADY BUT SECONDARY COLD FRONT WITH A
MORE PRONOUNCED PUNCH OF COOLER AND DRIER AIR STRETCHED FROM
NORTHERN WI SOUTH INTO EASTERN IOWA. NORTH/SOUTH AXIS OF DEWPOINTS
IN THE LOWER 70 DEWPOINTS OVER IL NORTH INTO SOUTHERN WISCONSIN IS
EXPECTED TO MIX OUT SOMEWHAT THIS AFTERNOON...BUT DEWPOINTS EXPECTED
TO REMAIN HIGH ENOUGH TO SUPPORT MLCAPE VALUES OF 2000+ J/KG WITH
LITTLE INHIBITION REMAINING BY MID AFTERNOON.
WINDS IN ADVANCE OF THE SECONDARY FRONT HAVE ALREADY SHIFTED TO WEST
AND NORTHWEST RESULTING IN VERY WEAK CONVERGENCE ALONG THE FRONT.
ACTUALLY...STRONGEST LOW LEVEL CONVERGENCE EXISTS ALONG THE WESTERN
SHORES OF LAKE MICHIGAN WHERE LAKE BREEZE HAS FORMED. OUTSIDE OF THE
LAKE BREEZE...TOUGH TO FIND ANY GOOD SURFACE FEATURES TO FOCUS LOW
LEVEL CONVERGENCE/ASCENT. ALOFT...ENCROACHING STREAM WILL RESULT IN
INCREASING ASCENT...WITH DEVELOPING ACCAS FIELD NOTED ON VSBL
SATELLITE IMAGERY OVER CENTRAL WISCONSIN LIKELY ALREADY AN
INDICATION OF THIS TAKING PLACE. VISIBLE SATELLITE IMAGERY ALSO
SHOWS AN AXIS OF CUMULUS BLOSSOMING ACROSS FAR EASTERN IL AND
WESTERN INDIANA.
OUTSIDE OF THE LAKE BREEZE...REALLY HARD TO FIND ANYTHING SPECIFIC
AT THIS POINT TO HANG MY HAT ON FOR PIN POINTING WHEN/WHERE
CONVECTION WILL DEVELOP THIS AFTERNOON. CONVECTIVE ALLOWING MODELS
CONTINUE TO BREAK OUT THUNDERSTORMS THIS AFTERNOON ACROSS THE REGION
AND GIVEN THE DESTABILIZATION THAT IS TAKING PLACE CAN`T DISPUTE
THIS. GIVEN THE ORIENTATION OF THE UPPER LEVEL JET THE BEST UPPER
LEVEL SUPPORT FOR CONVECTION WOULD APPEAR TO BE MORE SO OVER OUR
NORTHERN AND EASTERN CWA...BUT CERTAINLY THREAT DOES EXIST SOUTHWEST
CWA TOO.
RATHER NEBULOUS FORCING WOULD TEND TO FAVOR CONVECTION BEING MORE
CELLULAR/SCATTERED IN NATURE VS LINEAR. THE WOOD LAKE MN PROFILER
SHOWS 60-70KT FLOW AT 5-6KM WITH RAP SEEMINGLY HAVING A GOOD HANDLE
ON THIS SHOWING 50KT+ AT 5KM SPREADING SOUTHEAST ACROSS OUR CWA THIS
AFTERNOON RESULTING IN STRONG DEEP LAYER (0-6KM) SHEAR >40KT. THE
MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR ALONG WITH
ANTICIPATED CELLULAR NATURE OF THE CONVECTION WOULD LIKELY RESULT IN
SUPERCELLS. STRONG VEERED LOW LEVEL FLOW IS CERTAINLY NOT FAVORABLE
FOR TORNADOES...BUT THE STRONG SHEAR AND COOLING TEMPS ALOFT WITH
EXPECTED SUPERCELLULAR STORM MODE COULD RESULT IN LARGE
HAIL...POSSIBLY GREATER THAN 1.5 INCH DIAMETER. SOME THREAT WOULD
EXIST FOR DAMAGING WINDS AS WELL...THOUGH THE MORE PROMINENT THREAT
WOULD APPEAR TO BE LARGE HAIL.
WILL CONTINUE TO MONITOR FOR SIGNS OF CONVECTIVE INITIATION AND
PROVIDE UPDATES AS NEEDED.
IZZI
&&
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING.
* INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON.
KREIN
//DISCUSSION...UPDATED 12Z...
FOG HAS DEVELOPED OVERNIGHT ACROSS MUCH OF NORTHERN ILLINOIS AND
NORTHWEST INDIANA...BUT SHOULD DISSIPATE BY 13Z AS THE SUN BEGINS
TO HEAT THE SURFACE. NORTHWEST WINDS WILL ALSO GRADUALLY INCREASE
AROUND THIS TIME WITH A FEW GUSTS INTO THE MID TEENS POSSIBLE THIS
AFTERNOON AS WE MIX DEEPLY.
THUNDERSTORMS LOOK LIKELY AGAIN TODAY AS THE ATMOSPHERE QUICKLY
BECOMES UNSTABLE. BY 16-17Z FORECAST SOUNDINGS INDICATE SURFACE
BASED PARCELS WILL BE UNCAPPED...BUT THE BETTER FORCING APPEARS TO
ARRIVE LATER IN THE AFTERNOON AS A MID LEVEL DISTURBANCE AND UPPER
LEVEL JET BEGIN TO MOVE OVER THE AREA. THUNDERSTORMS ARE EXPECTED TO
BECOME STRONG TO SEVERE BUT SHOULD BE SCATTERED IN COVERAGE. THE
ONLY SIGNIFICANT FOCUS AT THE SURFACE WOULD BE A LAKE BREEZE THAT IS
EXPECTED TO STAY EAST OF THE CHICAGO TERMINALS.
THE THUNDERSTORM THREAT SHOULD FADE NOT TOO LONG AFTER SUNSET WITH
QUIET CONDITIONS EXPECTED OVERNIGHT. MODEST NORTHWEST FLOW SHOULD
INHIBIT FOG FROM DEVELOPING OVERNIGHT. ON FRIDAY...WINDS WILL BE A
LITTLE STRONGER OUT OF THE NORTHWEST WITH GUSTS TO AROUND 20 KT
POSSIBLE. THERE WILL BE ADDITIONAL CHANCES FOR THUNDERSTORMS FRIDAY
AFTERNOON AND EVENING.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING
AT SOME POINT THURSDAY AFTERNOON BUT DUE TO SCATTERED COVERAGE
LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
304 AM CDT
EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND
REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND
THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE
SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE
EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY
GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF
HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL
FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND.
WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY
TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE
WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY
THROUGH SUNDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
903 AM CDT THU JUN 27 2013
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING.
* INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON.
KREIN
//DISCUSSION...UPDATED 12Z...
FOG HAS DEVELOPED OVERNIGHT ACROSS MUCH OF NORTHERN ILLINOIS AND
NORTHWEST INDIANA...BUT SHOULD DISSIPATE BY 13Z AS THE SUN BEGINS
TO HEAT THE SURFACE. NORTHWEST WINDS WILL ALSO GRADUALLY INCREASE
AROUND THIS TIME WITH A FEW GUSTS INTO THE MID TEENS POSSIBLE THIS
AFTERNOON AS WE MIX DEEPLY.
THUNDERSTORMS LOOK LIKELY AGAIN TODAY AS THE ATMOSPHERE QUICKLY
BECOMES UNSTABLE. BY 16-17Z FORECAST SOUNDINGS INDICATE SURFACE
BASED PARCELS WILL BE UNCAPPED...BUT THE BETTER FORCING APPEARS TO
ARRIVE LATER IN THE AFTERNOON AS A MID LEVEL DISTURBANCE AND UPPER
LEVEL JET BEGIN TO MOVE OVER THE AREA. THUNDERSTORMS ARE EXPECTED TO
BECOME STRONG TO SEVERE BUT SHOULD BE SCATTERED IN COVERAGE. THE
ONLY SIGNIFICANT FOCUS AT THE SURFACE WOULD BE A LAKE BREEZE THAT IS
EXPECTED TO STAY EAST OF THE CHICAGO TERMINALS.
THE THUNDERSTORM THREAT SHOULD FADE NOT TOO LONG AFTER SUNSET WITH
QUIET CONDITIONS EXPECTED OVERNIGHT. MODEST NORTHWEST FLOW SHOULD
INHIBIT FOG FROM DEVELOPING OVERNIGHT. ON FRIDAY...WINDS WILL BE A
LITTLE STRONGER OUT OF THE NORTHWEST WITH GUSTS TO AROUND 20 KT
POSSIBLE. THERE WILL BE ADDITIONAL CHANCES FOR THUNDERSTORMS FRIDAY
AFTERNOON AND EVENING.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING
AT SOME POINT THURSDAY AFTERNOON BUT DUE TO SCATTERED COVERAGE
LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
304 AM CDT
EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND
REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND
THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE
SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE
EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY
GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF
HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL
FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND.
WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY
TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE
WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY
THROUGH SUNDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
641 AM CDT THU JUN 27 2013
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* FOG/BR DISSIPATING EARLY THURSDAY MORNING.
* THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING.
* INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON.
BMD
//DISCUSSION...UPDATED 12Z...
FOG HAS DEVELOPED OVERNIGHT ACROSS MUCH OF NORTHERN ILLINOIS AND
NORTHWEST INDIANA...BUT SHOULD DISSIPATE BY 13Z AS THE SUN BEGINS
TO HEAT THE SURFACE. NORTHWEST WINDS WILL ALSO GRADUALLY INCREASE
AROUND THIS TIME WITH A FEW GUSTS INTO THE MID TEENS POSSIBLE THIS
AFTERNOON AS WE MIX DEEPLY.
THUNDERSTORMS LOOK LIKELY AGAIN TODAY AS THE ATMOSPHERE QUICKLY
BECOMES UNSTABLE. BY 16-17Z FORECAST SOUNDINGS INDICATE SURFACE
BASED PARCELS WILL BE UNCAPPED...BUT THE BETTER FORCING APPEARS TO
ARRIVE LATER IN THE AFTERNOON AS A MID LEVEL DISTURBANCE AND UPPER
LEVEL JET BEGIN TO MOVE OVER THE AREA. THUNDERSTORMS ARE EXPECTED TO
BECOME STRONG TO SEVERE BUT SHOULD BE SCATTERED IN COVERAGE. THE
ONLY SIGNIFICANT FOCUS AT THE SURFACE WOULD BE A LAKE BREEZE THAT IS
EXPECTED TO STAY EAST OF THE CHICAGO TERMINALS.
THE THUNDERSTORM THREAT SHOULD FADE NOT TOO LONG AFTER SUNSET WITH
QUIET CONDITIONS EXPECTED OVERNIGHT. MODEST NORTHWEST FLOW SHOULD
INHIBIT FOG FROM DEVELOPING OVERNIGHT. ON FRIDAY...WINDS WILL BE A
LITTLE STRONGER OUT OF THE NORTHWEST WITH GUSTS TO AROUND 20 KT
POSSIBLE. THERE WILL BE ADDITIONAL CHANCES FOR THUNDERSTORMS FRIDAY
AFTERNOON AND EVENING.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN VSBY IMPROVING TO VFR BY 12-13Z.
* MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING
AT SOME POINT THURSDAY AFTERNOON BUT DUE TO SCATTERED COVERAGE
LOW CONFIDENCE ON SPECIFIC IMPACTS/TIMING.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHC SHRA.
SATURDAY...CHC TSRA/SHRA.
SUNDAY THROUGH MONDAY...VFR.
TUESDAY THROUGH WEDNESDAY...SLT CHC TSRA/SHRA.
BMD
&&
.MARINE...
304 AM CDT
EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND
REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND
THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE
SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE
EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY
GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF
HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL
FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND.
WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY
TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE
WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY
THROUGH SUNDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
407 AM CDT THU JUN 27 2013
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* FOG/BR DEVELOPMENT EARLY THIS MORNING.
* THUNDERSTORM CHANCES THIS AFTERNOON/EVENING.
* INLAND EXTENT OF LAKE BREEZE THIS AFTERNOON.
BMD
//DISCUSSION...UPDATED 06Z...
COLD FRONT PASSED THROUGH THE AREA LEAVING US UNDER NORTHWEST
FLOW THROUGH THE FORECAST PERIOD. OVERNIGHT...VERY LIGHT
WINDS...CALM OR VARIABLE AT TIMES...COUPLED WITH RECENT RAINFALL
AND PARTIAL CLEARING OVERHEAD WILL HELP SET THE STAGE FOR FOG
DEVELOPMENT. DOESNT APPEAR WE WILL COMPLETELY CLEAR OUT WHICH
WILL HELP TO SOME DEGREE...BUT DEW POINT DEPRESSIONS ARE ALREADY
ONLY A COUPLE/FEW DEGREES SO WONT TAKE MUCH COOLING THE REST OF
TONIGHT TO BEGIN TO SATURATE AND SEE VSBY REDUCTIONS. IN
ADDITION...SATURATED CONDITIONS OVER LAKE MICHIGAN MAY LEAD TO LOW
CIGS OR FOG MOVING INLAND OVER GYY TONIGHT.
EXPECT VSBY TO IMPROVE AND NORTHWEST FLOW TO PICK UP SOME SHORTLY
AFTER DAYBREAK THURSDAY MORNING. SHOULD BE A QUIET FIRST HALF OF THE
DAY...BUT BY EARLY AFTERNOON...MODELS SUGGEST THAT THE ATMOSPHERE
WILL ONCE AGAIN BECOME UNSTABLE AND UNCAPPED LEADING TO
THUNDERSTORMS DEVELOPING. APPEARS THE BEST TIME FRAME FOR TSTRMS
TO IMPACT THE TERMINALS WILL BE MID TO LATE AFTERNOON AS A MID
LEVEL DISTURBANCE MOVES OVERHEAD AS WELL AS A 100KT JET STREAK
WHICH WILL PROVIDE ADDITIONAL LIFT. A LAKE BREEZE MAY DEVELOP IN
THE RELATIVELY LIGHT NORTHWEST FLOW AT THE SURFACE...THOUGH IT IS
NOT CURRENTLY EXPECTED TO MAKE IT AS FAR INLAND AS ORD/MDW.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN MVFR VSBY THIS MORNING...LOW CONFIDENCE IN
DENSE FOG DEVELOPING.
* MEDIUM CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING AT SOME
POINT THIS AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
* FRIDAY AND SATURDAY...CHANCE OF SHRA/TSRA.
* SUNDAY...DRY.
* MONDAY AND TUESDAY...SLIGHT CHANCE OF TSRA.
&&
.MARINE...
304 AM CDT
EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND
REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND
THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE
SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE
EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY
GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF
HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL
FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND.
WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY
TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE
WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY
THROUGH SUNDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
402 AM CDT THU JUN 27 2013
.DISCUSSION...
359 AM CDT
A NORTHWEST FLOW PATTERN WITH ITS ATTENDANT SEVERE WEATHER
POSSIBILITIES IS BEGINNING TO TAKE SHAPE ACROSS THE AREA.
ANTICIPATED CAPE VALUES THIS AFTERNOON ARE NOT EXCESSIVE...GENERALLY
A BIT OVER 1000 J/KG AND FAIRLY SKINNY AT THAT...BUT 0-6 KM
UNIDIRECTIONAL NORTHWESTERLY SHEAR OF 40-50 KTS WOULD SUPPORT THE
POSSIBILITY OF SPLITTING SUPERCELLS. GIVEN THE RELATIVELY HIGH LCLS
AND RELATIVELY MARGINAL LOW LEVEL HELICITY EXPECTED
TODAY...TORNADOES WOULD NOT APPEAR TO BE THE PRIMARY CONCERN. THIS
CONCLUSION IS FURTHER SUPPORTED BY CIPS HISTORICAL ANALOGS WHICH
INSTEAD SHOW A CONCENTRATION OF HAIL AND WIND REPORTS OVER THE LOCAL
AREA ON DAYS THAT MOST RESEMBLED THIS ONE.
AS FOR TIMING TODAY...ALREADY THERE IS SOME ACTIVITY ACROSS EASTERN
WISCONSIN...BUT THIS APPEARS TO BE HEADING OVER THE LAKE RATHER THAN
DOWNSTREAM INTO ILLINOIS. THERE IS ADDITIONAL ACTIVITY FARTHER TO
THE NORTHWEST OVER MINNESOTA WHICH MAY EXPAND IN COVERAGE TOWARD
MORNING BUT ALSO APPEARS TO BE HEADING TOWARD THE LAKE. THE PRIMARY
DEVELOPMENT LOOKS LIKE IT WILL GET GOING TOWARD LATE MORNING IN THE
AREA OF A TROUGH DEPICTED BY THE RAP AT 850 MB OVER WISCONSIN. THIS
TROUGH DEEPENS AND MOVES INTO ILLINOIS BY EARLY AFTERNOON...TOGETHER
WITH A 50KT JET AT 500 MB AND WITH MOISTURE TRANSPORT INCREASING OUT
AHEAD OF IT. ACTIVITY SHOULD BEGIN TO DIMINISH AFTER SUNSET WITH
THE LOSS OF UPPER LEVEL SUPPORT AND DIURNAL HEATING.
THIS PATTERN OF A BROAD WESTERN CONUS ANTICYCLONE AND EASTERN CONUS
TROUGH WILL CONTINUE TO AMPLIFY OVER THE NEXT TWO DAYS. FRIDAY WILL
BE A TRANSITION DAY...NOT QUITE AS WARM AND UNSETTLED AS TODAY AND
NOT AS COOL AND SHOWERY AS SATURDAY. BY THE WEEKEND THE EASTERN
TROUGH WILL RETROGRADE ACROSS THE AREA...WITH THE AXIS ITSELF
SWINGING THROUGH ON SATURDAY. WITH IT COMES CONSIDERABLY COOLER
DAYTIME HIGHS AND A RENEWED CHANCE FOR MORE SHOWERS AND A FEW
THUNDERSTORMS.
FOR SUNDAY AND MONDAY THE TROUGH REMAINS OVERHEAD BUT THE MAIN AXIS
IS WELL SOUTH OF THE AREA...ALONG WITH THE BETTER LOW LEVEL
MOISTURE. DEEP LAYER CYCLONIC FLOW AND THE POSSIBILITY OF
SHORTWAVES DROPPING DOWN THE BACK SIDE OF THE TROUGH MIGHT SUPPORT
OVERCAST SKIES AND SOME ISOLATED SHOWERS...BUT PRECIP CHANCES ON
SUNDAY AND MONDAY ACROSS MOST OF THE AREA APPEAR TO BE CONSIDERABLY
LOWER THAN FOR SATURDAY.
MODELS ARE IN REASONABLE AGREEMENT SHOWING THE LONGWAVE TROUGH
CONTINUING ITS ODD RETROGRADE BACK OVER THE AREA ON TUESDAY.
UNFORTUNATELY THIS MEANS REINTRODUCING HIGHER PRECIP CHANCES FOR
MIDWEEK AND HEADING INTO INDEPENDENCE DAY. WEDNESDAY DOES LOOK A
BIT WARMER IF WINDS CAN MANAGE TO DEVELOP A SOUTHERLY COMPONENT.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* FOG/BR DEVELOPMENT EARLY THURSDAY MORNING.
* THUNDERSTORM CHANCES THURSDAY AFTERNOON/EVENING.
* INLAND EXTENT OF LAKE BREEZE THURSDAY AFTERNOON.
BMD
//DISCUSSION...UPDATED 06Z...
COLD FRONT PASSED THROUGH THE AREA LEAVING US UNDER NORTHWEST
FLOW THROUGH THE FORECAST PERIOD. OVERNIGHT...VERY LIGHT
WINDS...CALM OR VARIABLE AT TIMES...COUPLED WITH RECENT RAINFALL
AND PARTIAL CLEARING OVERHEAD WILL HELP SET THE STAGE FOR FOG
DEVELOPMENT. DOESNT APPEAR WE WILL COMPLETELY CLEAR OUT WHICH
WILL HELP TO SOME DEGREE...BUT DEW POINT DEPRESSIONS ARE ALREADY
ONLY A COUPLE/FEW DEGREES SO WONT TAKE MUCH COOLING THE REST OF
TONIGHT TO BEGIN TO SATURATE AND SEE VSBY REDUCTIONS. IN
ADDITION...SATURATED CONDITIONS OVER LAKE MICHIGAN MAY LEAD TO LOW
CIGS OR FOG MOVING INLAND OVER GYY TONIGHT.
EXPECT VSBY TO IMPROVE AND NORTHWEST FLOW TO PICK UP SOME SHORTLY
AFTER DAYBREAK THURSDAY MORNING. SHOULD BE A QUIET FIRST HALF OF THE
DAY...BUT BY EARLY AFTERNOON...MODELS SUGGEST THAT THE ATMOSPHERE
WILL ONCE AGAIN BECOME UNSTABLE AND UNCAPPED LEADING TO
THUNDERSTORMS DEVELOPING. APPEARS THE BEST TIME FRAME FOR TSTRMS
TO IMPACT THE TERMINALS WILL BE MID TO LATE AFTERNOON AS A MID
LEVEL DISTURBANCE MOVES OVERHEAD AS WELL AS A 100KT JET STREAK
WHICH WILL PROVIDE ADDITIONAL LIFT. A LAKE BREEZE MAY DEVELOP IN
THE RELATIVELY LIGHT NORTHWEST FLOW AT THE SURFACE...THOUGH IT IS
NOT CURRENTLY EXPECTED TO MAKE IT AS FAR INLAND AS ORD/MDW.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN SOME REDUCTION TO VSBY OVERNIGHT...LOW
CONFIDENCE IN DENSE FOG DEVELOPING.
* MEDIUM CONFIDENCE IN ADDITIONAL THUNDERSTORMS DEVELOPING AT SOME
POINT THURSDAY AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING...LOW
CONFIDENCE IT WILL REACH TERMINALS.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
* FRIDAY AND SATURDAY...CHANCE OF SHRA/TSRA.
* SUNDAY...DRY.
* MONDAY AND TUESDAY...SLIGHT CHANCE OF TSRA.
&&
.MARINE...
304 AM CDT
EARLY THIS MORNING THE LAKE IS UNDER A WEAK GRADIENT AND WIND
REGIME BETWEEN TWO AREAS OF LOW PRESSURE..ONE OVER MICHIGAN AND
THE OTHER OVER MANITOBA. THE NORTHERN LOW IS FORECAST TO MOVE
SOUTHEAST AND WEAKEN WHILE THE OTHER LOW MOVES EAST INTO THE
EASTERN GREAT LAKES. THIS WILL ALLOW A MODEST NORTHWESTERLY
GRADIENT TO SLOWLY OVERSPREAD THE LAKE THROUGH THE DAY AHEAD OF
HIGH PRESSURE THAT IS BUILDING ACROSS THE PLAINS. WINDS WILL
FRESHEN UP TO 10 TO 20 KT FRIDAY...AND 15 TO 25 KT THIS WEEKEND.
WINDS SHOULD THEN BEGIN TO WEAKEN SOME MONDAY...AND ESPECIALLY
TUESDAY AND WEDNESDAY AS THE HIGH BUILDS ACROSS THE LAKE. THERE
WILL BE PERIODIC CHANCES FOR THUNDERSTORMS ACROSS THE LAKE TODAY
THROUGH SUNDAY. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1259 PM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1246 PM CDT THU JUN 27 2013
RAP TRENDS CONTINUE TO SHOW THE 800-750MB CONVERGENCE HELPING TO
DRIVE THE NORTHERN PART OF THE PRECIPITATION. HOWEVER...IT IS
ENCOUNTERING CONSIDERABLE DRY AIR SO NEARLY ALL THE PRECIPITATION
IS EVAPORATING BEFORE IT REACHES THE GROUND. SOME SITES HAVE
REPORTED RAIN BUT FROM A DECK AROUND 10 KFT. AS SUCH SPRINKLES ARE
BEING REPORTED WHICH IS CAUSING BRIEF GUSTY WINDS AND HELPING TO
LOWER DEW POINTS/TEMPERATURES.
THE CLOUD COVER WILL HELP SUPPRESS TEMPERATURES BUT MOST AREAS ARE
ALREADY IN THE MID AND UPPER 80S. WHERE SUN IS STILL OCCURRING
TEMPERATURES WILL RISE A BIT MORE DURING THE AFTERNOON.
RAP TRENDS CONTINUE TO SUGGEST THE POTENTIAL FOR DIURNAL
CONVECTION OVER ROUGHLY THE SOUTHERN QUARTER OF THE CWFA. THE
CLOUD COVER BRINGS A QUESTION MARK TO WHETHER OR NOT THE
CONVECTIVE TEMPERATURE WILL BE ACHIEVED OVER THE REMAINDER OF THE
AREA. ..08..
UPDATE ISSUED AT 957 AM CDT THU JUN 27 2013
12Z SOUNDING SHOWS A RESPECTABLE SFC CAP IN PLACE WITH A
CONVECTIVE TEMPERATURE IN THE LOWER 90S. 12Z UA ANALYSIS COMBINED
WITH THE MCS AND LIFT TOOLS HELP EXPLAIN THE CURRENT CONVECTION IN
THE PLAINS. THE CONVECTION IN SOUTHEAST NEBRASKA IS DRIVEN BY A
SMALL SHORTWAVE AND IS RUNNING ALONG THE 850MB MOISTURE GRADIENT.
FURTHER NORTH FROM SOUTH DAKOTA INTO NORTHWEST IOWA THERE IS NICE
CONVERGENCE IN THE 800-750MB LAYER WITH A THETA E GRADIENT PRESENT.
OVERALL FORCING WHEN USED WITH THE MCS AND LIFT TOOLS INDICATE DRY
CONDITIONS WILL REMAIN IN PLACE ACROSS THE CWFA DURING THE MORNING
HOURS WITH DOWNWARD MOTION ACROSS THE AREA. THE SOUTH
DAKOTA/NORTHWEST IOWA CONVECTION WILL SLOWLY DISSIPATE AS IT MOVES
INTO DRIER AIR AND THE CONVERGENCE MOVES SOUTH AND EAST.
THE MCS/LIFT TOOLS SHOW THE 800-750MB CONVERGENCE MOVING SOUTHEAST
AND ENTERING THE FAR SOUTHWEST/SOUTH PARTS OF THE CWFA SHORTLY
AFTER MID DAY. HOWEVER...THE THETA E GRADIENT IS VERY WEAK.
FCST SOUNDINGS OFF THE RAP SUGGEST CONVECTIVE TEMPERATURES
REMAINING AT 90 OR ABOVE BUT SHOW OVERALL LIFT INCREASING DURING
THE AFTERNOON AS A VORT MAX MOVES THROUGH. THUS DIURNAL CLOUDS
WILL DEVELOP. IF THE RAP TRENDS ON CONVECTIVE TEMPERATURE ARE
CORRECT...THE POTENTIAL EXISTS FOR VERY LITTLE IN THE WAY OF
AFTERNOON CONVECTION. TRENDS WILL HAVE TO BE MONITORED BUT POPS
HAVE BEEN PULLED BACK TO THE FAR SOUTHWEST/SOUTH AND FAR NORTHEAST
FOR ISOLATED TO SCATTERED CONVECTION. ..08..
&&
.SYNOPSIS...
ISSUED AT 340 AM CDT THU JUN 27 2013
STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE
TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW
FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK
RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS
FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK
SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT
POPPED UP OVER NW IL THIS MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT THU JUN 27 2013
MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE
FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED
OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED
SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO
FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE
BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND
POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH
A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR
SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO
MAKE IT THIS FAR EAST.
A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER
FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD
WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND
CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A
SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH
FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE
WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL
THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL
CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE
CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE
SCATTERED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU JUN 27 2013
INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE
SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS
SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER
STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON
SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION.
THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN.
SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1246 PM CDT THU JUN 27 2013
VFR CONDITIONS ARE EXPECTED THROUGH 18Z/28. A LOOSELY ORGANIZED
TSRA COMPLEX IS MOVING SOUTHEAST ACROSS SOUTHERN IOWA AND INTO
MISSOURI. CONSIDERABLE DRY AIR ALOFT IS CAUSING THE PRECIPITATION
TO NEARLY EVAPORATE PRIOR TO REACHING THE GROUND. CLOUD COVER FROM
THIS SYSTEM MAY PREVENT DIURNAL CONVECTION FROM OCCURRING ACROSS
EASTERN IOWA AND NORTHERN ILLINOIS. IF DIURNAL CONVECTION
OCCURS...THE PROBABILITY OF IT AFFECTING A TAF SITE IS UNDER 15
PERCENT. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...14
AVIATION...08
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1232 PM CDT THU JUN 27 2013
.SHORT TERM.../TODAY/...
ISSUED AT 357 AM CDT THU JUN 27 2013
WEAK SHORTWAVE WILL CONTINUE TO CUT ACROSS EASTERN SD INTO
EASTERN NE AND WESTERN IA THIS MORNING. THE HI-RES MODELS KEEP THE
PRECIP CONFINED TO THE SOUTHWEST PORTIONS OF THE FORECAST AREA
EXCEPT THE 06Z HRRR WHERE ITS FURTHER EAST AND IS A BIT MORE
BULLISH WITH THE COVERAGE. LITTLE MOISTURE AND FORCING WITH THIS
SYSTEM AND ANYTHING THAT DEVELOPS WILL BE HIGH BASED AND SO LEANED
TOWARD THE HIRES-NMM MODEL RUNS AS IT SEEMED TO HAVE THE BEST
SOLUTION WRT TO LOCATION AND TIMING OF PRECIP. CURRENT RADAR
TRENDS HAVE THE PRECIP MOVING INTO THE WESTERN FORECAST AREA BY
AROUND 10Z OR SHORTLY AFTER AND LOOK TO BE MORE SOUTHEAST.
HOWEVER...THE LATEST RAP CORFIDI VECTORS AND STORM MOTION VECTORS
SHIFT THE PRECIP MOVEMENT MORE SOUTHERLY AS IT MOVES EAST.
HIGH TEMPS TODAY SHOULD BE FAIRLY SIMILAR TO WEDNESDAY...MAYBE
SLIGHTLY COOLER OVER THE WEST TO SOUTH WHERE THE PRECIP AND MORE
CLOUD COVER WILL BE THIS MORNING. WAS CONFIDENT ENOUGH TO GO ABOVE
GUIDANCE FOR HIGHS TODAY.
.LONG TERM.../TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 357 AM CDT THU JUN 27 2013
NO SIGNIFICANT CONCERNS THROUGH THIS PERIOD BUT WITH DEFINITE
PATTERN CHANGE COMING. MCS MAY BE LINGERING OVER SRN IA AT 00Z WITH
THERMODYNAMIC FORCING JUST EXITING INTO MO. THIS WILL LEAD TO FAIR
WEATHER LATER THU NIGHT AND INTO EARLY FRI AS LONG WAVE PATTERN
BEGINS TO AMPLIFY INTO WRN CONUS TROUGH/ERN RIDGE. HOWEVER BY FRI
AFTERNOON REMNANTS OF CURRENT COMPACT MANITOBA SHORT WAVE WILL BEGIN
DROPPING INTO WRN SIDE OF GREAT LAKES MEAN TROUGH. THIS WILL
GRADUALLY INCREASE SUB 3KM MOISTURE NE-SW...AND COUPLED WITH DAYTIME
HEATING...PRODUCE WEAK BUT UNCAPPED SEVERAL HUNDRED MLCAPES. THIS
WILL LIKELY DEVELOP SCATTERED UNORGANIZED WEAK PEAK HEATING
CONVECTION NE...WHICH IS DEPICTED IN NAM AND HI RES MODEL SIMULATED
REFLECTIVITY. LATE DAY MIXING PRODUCING THE INSTABILITY WILL ALSO
LIKELY ALLOW BRISK NW WINDS TO MIX DOWN AS SLP GRADIENT INCREASES
WITH GUSTS AT OR ABOVE 30 MPH POSSIBLE CENTRAL AND NORTH.
BY SATURDAY...THERE IS LITTLE EVIDENCE OF ANY QG FORCING AS
AFOREMENTIONED VORT AXIS DROPS THROUGH MS VALLEY. MAIN RESULT WILL
BE INCREASED DEEP MOISTURE WITH SOUNDINGS SHOWING NEAR SATURATION AT
MANY SITES. THIS ENVIRONMENT WILL LIKELY PRODUCE AREAS OF LIGHT
SHOWERS INTO SAT...POSSIBLY LINGERING INTO THE SE EARLY EVENING.
HAVE RAISED POPS FURTHER THROUGH THE CHANCE CATEGORY. COULD SEE
SOME THUNDER BUT NOTHING SEVERE ANTICIPATED.
THE LONG WAVE PATTERN WILL CHANGE LITTLE TO END THE WEEKEND WITH
PERSISTENT WEST/EAST TROUGH/RIDGE BUT WITH WEAKENING FLOW. SOME
RETROGRESSION WILL EVEN OCCUR BY EARLY NEXT WEEK WITH TROUGH
EVENTUALLY DRIFTING WWD INTO MS VALLEY. MID/LOWER TROPOSPHERIC FLOW
WILL BE RATHER WEAK IN THIS TIME FRAME WITH LITTLE FORCING. THERE
IS SOME POTENTIAL FOR PRECIP...BUT CONFIDENCE IN TIMING OR LOCATION
IS NOT GREAT ENOUGH TO INCLUDE MENTION AT THE MOMENT. HOWEVER BY
LATE TUE INTO WED TROUGH AND ASSOCIATED FORCING INCREASES SLIGHTLY
WHICH JUSTIFIES LOW CHANCES BY THAT TIME.
TEMPERATURE WISE...READINGS WILL BE BELOW NORMAL WITH
CORRESPONDINGLY LOWER DEWPOINTS. FRIDAY COULD VERY WELL BE THE LAST
DAY WE EXCEED 80F FOR THE DURATION OF THE PERIOD AREA WIDE. IN FACT
GFS/ECMWF H85 TEMP TIME SERIES THROUGH THE FOLLOWING WEEKEND /JUL 6/
SHOWS LITTLE EVIDENCE OF ANY RETURN TO WARM AND HUMID WEATHER.
&&
.AVIATION...27/18Z
ISSUED AT 1232 PM CDT THU JUN 27 2013
SCT -SHRA MOVING ACROSS SRN IA WILL AFFECT KDSM/KOTM AT TIMES IN
THE NEXT FEW HRS...BUT ANY VSBY RESTRICTIONS WILL BE BRIEF AND
GENERALLY 4-6SM. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THE
TAF PERIOD WITH HIGH CLOUDS AT TIMES AND NW WINDS INCR/DECR WITH
DAY/NIGHT PERIODS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...SMALL
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1009 AM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 957 AM CDT THU JUN 27 2013
12Z SOUNDING SHOWS A RESPECTABLE SFC CAP IN PLACE WITH A
CONVECTIVE TEMPERATURE IN THE LOWER 90S. 12Z UA ANALYSIS COMBINED
WITH THE MCS AND LIFT TOOLS HELP EXPLAIN THE CURRENT CONVECTION IN
THE PLAINS. THE CONVECTION IN SOUTHEAST NEBRASKA IS DRIVEN BY A
SMALL SHORTWAVE AND IS RUNNING ALONG THE 850MB MOISTURE GRADIENT.
FURTHER NORTH FROM SOUTH DAKOTA INTO NORTHWEST IOWA THERE IS NICE
CONVERGENCE IN THE 800-750MB LAYER WITH A THETA E GRADIENT PRESENT.
OVERALL FORCING WHEN USED WITH THE MCS AND LIFT TOOLS INDICATE DRY
CONDITIONS WILL REMAIN IN PLACE ACROSS THE CWFA DURING THE MORNING
HOURS WITH DOWNWARD MOTION ACROSS THE AREA. THE SOUTH
DAKOTA/NORTHWEST IOWA CONVECTION WILL SLOWLY DISSIPATE AS IT MOVES
INTO DRIER AIR AND THE CONVERGENCE MOVES SOUTH AND EAST.
THE MCS/LIFT TOOLS SHOW THE 800-750MB CONVERGENCE MOVING SOUTHEAST
AND ENTERING THE FAR SOUTHWEST/SOUTH PARTS OF THE CWFA SHORTLY
AFTER MID DAY. HOWEVER...THE THETA E GRADIENT IS VERY WEAK.
FCST SOUNDINGS OFF THE RAP SUGGEST CONVECTIVE TEMPERATURES
REMAINING AT 90 OR ABOVE BUT SHOW OVERALL LIFT INCREASING DURING
THE AFTERNOON AS A VORT MAX MOVES THROUGH. THUS DIURNAL CLOUDS
WILL DEVELOP. IF THE RAP TRENDS ON CONVECTIVE TEMPERATURE ARE
CORRECT...THE POTENTIAL EXISTS FOR VERY LITTLE IN THE WAY OF
AFTERNOON CONVECTION. TRENDS WILL HAVE TO BE MONITORED BUT POPS
HAVE BEEN PULLED BACK TO THE FAR SOUTHWEST/SOUTH AND FAR NORTHEAST
FOR ISOLATED TO SCATTERED CONVECTION. ..08..
&&
.SYNOPSIS...
ISSUED AT 340 AM CDT THU JUN 27 2013
STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE
TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW
FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK
RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS
FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK
SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT
POPPED UP OVER NW IL THIS MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT THU JUN 27 2013
MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE
FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED
OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED
SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO
FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE
BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND
POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH
A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR
SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO
MAKE IT THIS FAR EAST.
A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER
FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD
WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND
CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A
SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH
FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE
WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL
THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL
CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE
CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE
SCATTERED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU JUN 27 2013
INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE
SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS
SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER
STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON
SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION.
THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN.
SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 613 AM CDT THU JUN 27 2013
AN AREA OF THUNDERSTORMS OVER EASTERN NEBRASKA AND SOUTH DAKOTA IS
EXPECTED TO WEAKEN AS IT MOVES SOUTHEAST ACROSS INTO SOUTHERN
IOWA AND WESTERN ILLINOIS TODAY. A SECOND AREA OF SCATTERED
THUNDERSTORMS IS EXPECTED TO DEVELOP OVER NORTHERN ILLINOIS THIS
AFTERNOON. OUTSIDE OF THUNDERSTORMS...VFR CONDITIONS WILL PREVAIL
THROUGH TONIGHT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...14
AVIATION...DMD
AREA FORECAST DISCUSSION
NWS DES MOINES IA
649 AM CDT THU JUN 27 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM.../TODAY/...
ISSUED AT 357 AM CDT THU JUN 27 2013
WEAK SHORTWAVE WILL CONTINUE TO CUT ACROSS EASTERN SD INTO
EASTERN NE AND WESTERN IA THIS MORNING. THE HI-RES MODELS KEEP THE
PRECIP CONFINED TO THE SOUTHWEST PORTIONS OF THE FORECAST AREA
EXCEPT THE 06Z HRRR WHERE ITS FURTHER EAST AND IS A BIT MORE
BULLISH WITH THE COVERAGE. LITTLE MOISTURE AND FORCING WITH THIS
SYSTEM AND ANYTHING THAT DEVELOPS WILL BE HIGH BASED AND SO LEANED
TOWARD THE HIRES-NMM MODEL RUNS AS IT SEEMED TO HAVE THE BEST
SOLUTION WRT TO LOCATION AND TIMING OF PRECIP. CURRENT RADAR
TRENDS HAVE THE PRECIP MOVING INTO THE WESTERN FORECAST AREA BY
AROUND 10Z OR SHORTLY AFTER AND LOOK TO BE MORE SOUTHEAST.
HOWEVER...THE LATEST RAP CORFIDI VECTORS AND STORM MOTION VECTORS
SHIFT THE PRECIP MOVEMENT MORE SOUTHERLY AS IT MOVES EAST.
HIGH TEMPS TODAY SHOULD BE FAIRLY SIMILAR TO WEDNESDAY...MAYBE
SLIGHTLY COOLER OVER THE WEST TO SOUTH WHERE THE PRECIP AND MORE
CLOUD COVER WILL BE THIS MORNING. WAS CONFIDENT ENOUGH TO GO ABOVE
GUIDANCE FOR HIGHS TODAY.
.LONG TERM.../TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 357 AM CDT THU JUN 27 2013
NO SIGNIFICANT CONCERNS THROUGH THIS PERIOD BUT WITH DEFINITE
PATTERN CHANGE COMING. MCS MAY BE LINGERING OVER SRN IA AT 00Z WITH
THERMODYNAMIC FORCING JUST EXITING INTO MO. THIS WILL LEAD TO FAIR
WEATHER LATER THU NIGHT AND INTO EARLY FRI AS LONG WAVE PATTERN
BEGINS TO AMPLIFY INTO WRN CONUS TROUGH/ERN RIDGE. HOWEVER BY FRI
AFTERNOON REMNANTS OF CURRENT COMPACT MANITOBA SHORT WAVE WILL BEGIN
DROPPING INTO WRN SIDE OF GREAT LAKES MEAN TROUGH. THIS WILL
GRADUALLY INCREASE SUB 3KM MOISTURE NE-SW...AND COUPLED WITH DAYTIME
HEATING...PRODUCE WEAK BUT UNCAPPED SEVERAL HUNDRED MLCAPES. THIS
WILL LIKELY DEVELOP SCATTERED UNORGANIZED WEAK PEAK HEATING
CONVECTION NE...WHICH IS DEPICTED IN NAM AND HI RES MODEL SIMULATED
REFLECTIVITY. LATE DAY MIXING PRODUCING THE INSTABILITY WILL ALSO
LIKELY ALLOW BRISK NW WINDS TO MIX DOWN AS SLP GRADIENT INCREASES
WITH GUSTS AT OR ABOVE 30 MPH POSSIBLE CENTRAL AND NORTH.
BY SATURDAY...THERE IS LITTLE EVIDENCE OF ANY QG FORCING AS
AFOREMENTIONED VORT AXIS DROPS THROUGH MS VALLEY. MAIN RESULT WILL
BE INCREASED DEEP MOISTURE WITH SOUNDINGS SHOWING NEAR SATURATION AT
MANY SITES. THIS ENVIRONMENT WILL LIKELY PRODUCE AREAS OF LIGHT
SHOWERS INTO SAT...POSSIBLY LINGERING INTO THE SE EARLY EVENING.
HAVE RAISED POPS FURTHER THROUGH THE CHANCE CATEGORY. COULD SEE
SOME THUNDER BUT NOTHING SEVERE ANTICIPATED.
THE LONG WAVE PATTERN WILL CHANGE LITTLE TO END THE WEEKEND WITH
PERSISTENT WEST/EAST TROUGH/RIDGE BUT WITH WEAKENING FLOW. SOME
RETROGRESSION WILL EVEN OCCUR BY EARLY NEXT WEEK WITH TROUGH
EVENTUALLY DRIFTING WWD INTO MS VALLEY. MID/LOWER TROPOSPHERIC FLOW
WILL BE RATHER WEAK IN THIS TIME FRAME WITH LITTLE FORCING. THERE
IS SOME POTENTIAL FOR PRECIP...BUT CONFIDENCE IN TIMING OR LOCATION
IS NOT GREAT ENOUGH TO INCLUDE MENTION AT THE MOMENT. HOWEVER BY
LATE TUE INTO WED TROUGH AND ASSOCIATED FORCING INCREASES SLIGHTLY
WHICH JUSTIFIES LOW CHANCES BY THAT TIME.
TEMPERATURE WISE...READINGS WILL BE BELOW NORMAL WITH
CORRESPONDINGLY LOWER DEWPOINTS. FRIDAY COULD VERY WELL BE THE LAST
DAY WE EXCEED 80F FOR THE DURATION OF THE PERIOD AREA WIDE. IN FACT
GFS/ECMWF H85 TEMP TIME SERIES THROUGH THE FOLLOWING WEEKEND /JUL 6/
SHOWS LITTLE EVIDENCE OF ANY RETURN TO WARM AND HUMID WEATHER.
&&
.AVIATION...27/12Z
ISSUED AT 648 AM CDT THU JUN 27 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH SOME MID
TO HIGH LEVEL CLOUDS ACROSS SOUTHWEST IOWA AS A SHORTWAVE MOVES
THROUGH EASTERN NEBRASKA. SOME MIXING EXPECTED TO AND CONTINUED
WITH GUSTS IN THE UPPER TEENS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...SMALL
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
619 AM CDT THU JUN 27 2013
.SYNOPSIS...
ISSUED AT 340 AM CDT THU JUN 27 2013
STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE
TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW
FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK
RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS
FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK
SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT
POPPED UP OVER NW IL THIS MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT THU JUN 27 2013
MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE
FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED
OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED
SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO
FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE
BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND
POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH
A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR
SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO
MAKE IT THIS FAR EAST.
A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER
FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD
WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND
CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A
SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH
FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE
WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL
THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL
CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE
CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE
SCATTERED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU JUN 27 2013
INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE
SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS
SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER
STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON
SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION.
THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN.
SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 613 AM CDT THU JUN 27 2013
AN AREA OF THUNDERSTORMS OVER EASTERN NEBRASKA AND SOUTH DAKOTA IS
EXPECTED TO WEAKEN AS IT MOVES SOUTHEAST ACROSS INTO SOUTHERN
IOWA AND WESTERN ILLINOIS TODAY. A SECOND AREA OF SCATTERED
THUNDERSTORMS IS EXPECTED TO DEVELOP OVER NORTHERN ILLINOIS THIS
AFTERNOON. OUTSIDE OF THUNDERSTORMS...VFR CONDITIONS WILL PREVAIL
THROUGH TONIGHT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...14
AVIATION...DMD
AREA FORECAST DISCUSSION
NWS DES MOINES IA
358 AM CDT THU JUN 27 2013
.SHORT TERM.../TODAY/...
ISSUED AT 357 AM CDT THU JUN 27 2013
WEAK SHORTWAVE WILL CONTINUE TO CUT ACROSS EASTERN SD INTO
EASTERN NE AND WESTERN IA THIS MORNING. THE HI-RES MODELS KEEP THE
PRECIP CONFINED TO THE SOUTHWEST PORTIONS OF THE FORECAST AREA
EXCEPT THE 06Z HRRR WHERE ITS FURTHER EAST AND IS A BIT MORE
BULLISH WITH THE COVERAGE. LITTLE MOISTURE AND FORCING WITH THIS
SYSTEM AND ANYTHING THAT DEVELOPS WILL BE HIGH BASED AND SO LEANED
TOWARD THE HIRES-NMM MODEL RUNS AS IT SEEMED TO HAVE THE BEST
SOLUTION WRT TO LOCATION AND TIMING OF PRECIP. CURRENT RADAR
TRENDS HAVE THE PRECIP MOVING INTO THE WESTERN FORECAST AREA BY
AROUND 10Z OR SHORTLY AFTER AND LOOK TO BE MORE SOUTHEAST.
HOWEVER...THE LATEST RAP CORFIDI VECTORS AND STORM MOTION VECTORS
SHIFT THE PRECIP MOVEMENT MORE SOUTHERLY AS IT MOVES EAST.
HIGH TEMPS TODAY SHOULD BE FAIRLY SIMILAR TO WEDNESDAY...MAYBE
SLIGHTLY COOLER OVER THE WEST TO SOUTH WHERE THE PRECIP AND MORE
CLOUD COVER WILL BE THIS MORNING. WAS CONFIDENT ENOUGH TO GO ABOVE
GUIDANCE FOR HIGHS TODAY.
.LONG TERM.../TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 357 AM CDT THU JUN 27 2013
NO SIGNIFICANT CONCERNS THROUGH THIS PERIOD BUT WITH DEFINITE
PATTERN CHANGE COMING. MCS MAY BE LINGERING OVER SRN IA AT 00Z WITH
THERMODYNAMIC FORCING JUST EXITING INTO MO. THIS WILL LEAD TO FAIR
WEATHER LATER THU NIGHT AND INTO EARLY FRI AS LONG WAVE PATTERN
BEGINS TO AMPLIFY INTO WRN CONUS TROUGH/ERN RIDGE. HOWEVER BY FRI
AFTERNOON REMNANTS OF CURRENT COMPACT MANITOBA SHORT WAVE WILL BEGIN
DROPPING INTO WRN SIDE OF GREAT LAKES MEAN TROUGH. THIS WILL
GRADUALLY INCREASE SUB 3KM MOISTURE NE-SW...AND COUPLED WITH DAYTIME
HEATING...PRODUCE WEAK BUT UNCAPPED SEVERAL HUNDRED MLCAPES. THIS
WILL LIKELY DEVELOP SCATTERED UNORGANIZED WEAK PEAK HEATING
CONVECTION NE...WHICH IS DEPICTED IN NAM AND HI RES MODEL SIMULATED
REFLECTIVITY. LATE DAY MIXING PRODUCING THE INSTABILITY WILL ALSO
LIKELY ALLOW BRISK NW WINDS TO MIX DOWN AS SLP GRADIENT INCREASES
WITH GUSTS AT OR ABOVE 30 MPH POSSIBLE CENTRAL AND NORTH.
BY SATURDAY...THERE IS LITTLE EVIDENCE OF ANY QG FORCING AS
AFOREMENTIONED VORT AXIS DROPS THROUGH MS VALLEY. MAIN RESULT WILL
BE INCREASED DEEP MOISTURE WITH SOUNDINGS SHOWING NEAR SATURATION AT
MANY SITES. THIS ENVIRONMENT WILL LIKELY PRODUCE AREAS OF LIGHT
SHOWERS INTO SAT...POSSIBLY LINGERING INTO THE SE EARLY EVENING.
HAVE RAISED POPS FURTHER THROUGH THE CHANCE CATEGORY. COULD SEE
SOME THUNDER BUT NOTHING SEVERE ANTICIPATED.
THE LONG WAVE PATTERN WILL CHANGE LITTLE TO END THE WEEKEND WITH
PERSISTENT WEST/EAST TROUGH/RIDGE BUT WITH WEAKENING FLOW. SOME
RETROGRESSION WILL EVEN OCCUR BY EARLY NEXT WEEK WITH TROUGH
EVENTUALLY DRIFTING WWD INTO MS VALLEY. MID/LOWER TROPOSPHERIC FLOW
WILL BE RATHER WEAK IN THIS TIME FRAME WITH LITTLE FORCING. THERE
IS SOME POTENTIAL FOR PRECIP...BUT CONFIDENCE IN TIMING OR LOCATION
IS NOT GREAT ENOUGH TO INCLUDE MENTION AT THE MOMENT. HOWEVER BY
LATE TUE INTO WED TROUGH AND ASSOCIATED FORCING INCREASES SLIGHTLY
WHICH JUSTIFIES LOW CHANCES BY THAT TIME.
TEMPERATURE WISE...READINGS WILL BE BELOW NORMAL WITH
CORRESPONDINGLY LOWER DEWPOINTS. FRIDAY COULD VERY WELL BE THE LAST
DAY WE EXCEED 80F FOR THE DURATION OF THE PERIOD AREA WIDE. IN FACT
GFS/ECMWF H85 TEMP TIME SERIES THROUGH THE FOLLOWING WEEKEND /JUL 6/
SHOWS LITTLE EVIDENCE OF ANY RETURN TO WARM AND HUMID WEATHER.
&&
.AVIATION...27/06Z
ISSUED AT 1156 PM CDT WED JUN 26 2013
VFR CONDITIONS THROUGHOUT THE TAF PERIOD. WESTERLY TO
NORTHWESTERLY WINDS TO PICK UP THURSDAY BEFORE DIMINISHING
WITH SUNSET THURSDAY EVENING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...SMALL
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
342 AM CDT THU JUN 27 2013
.SYNOPSIS...
ISSUED AT 340 AM CDT THU JUN 27 2013
STRONG UPPER RIDGE DOMINATES THE WESTERN CONUS...WITH A LONG WAVE
TROUGH OVER THE OHIO VALLEY. IN BETWEEN...NORTHWEST FLOW IS NOW
FIRMLY ENTRENCHED OVER THE UPPER MIDWEST. AT THE SURFACE...WEAK
RIDGING IS IN PLACE OVER THE LOCAL AREA...WHILE A COLD FRONT EXTENDS
FROM MANITOBA INTO THE NEBRASKA PANHANDLE. WATER VAPOR SHOWS WEAK
SHORT WAVE PUSHING THROUGH SOUTHERN WI...HENCE THE FEW SHOWERS THAT
POPPED UP OVER NW IL THIS MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT THU JUN 27 2013
MAIN FORECAST CONCERN TODAY IS PRECIP CHANCES...AND FOR THAT WE
FIRST TURN OUR ATTENTION TO THE CONVECTION THAT HAS DEVELOPED
OVERNIGHT OVER SOUTH DAKOTA. THE IDEA OF THIS CONVECTION IS CAPTURED
SLIGHTLY BY THE NAM AND ECMWF...ALTHOUGH BOTH HAVE IT POSITIONED TOO
FAR SOUTH. THE RAP MISSES IT ENTIRELY. THE HRRR LOOKS TO HAVE THE
BEST HANDLE ON THE CURRENT RADAR TRENDS INCLUDING EXTENT AND
POSITION SO WILL USE THAT AS THE BASIS FOR THE VERY SHORT TERM WITH
A MINOR ADJUSTMENT SOUTHWARD. END RESULT WILL BE LOW POPS IN OUR
SOUTHWEST SECTION THIS AFTERNOON FOR ANY REMNANTS THAT MANAGE TO
MAKE IT THIS FAR EAST.
A SECOND AREA OF CONCERN THIS AFTERNOON IS NORTHWEST ILLINOIS. UPPER
FLOW IS FORECAST TO AMPLIFY TODAY AND BOUNDARY LAYER TEMPS SHOULD
WARM WELL INTO THE 80S. FORECAST SOUNDINGS SHOW 1000+ CAPES AND
CONVECTIVE TEMP IN THE MID 80S SHOULD BE EASILY REACHED. SPC NOTES A
SLIGHT RISK DUE TO MODERATE INSTABILITY AND ADEQUATE SHEAR. WITH
FAIRLY UNIDIRECTIONAL SHEAR IN NORTHWEST FLOW...MAIN THREAT WOULD BE
WIND. IF ENOUGH DRYING COMES IN ALOFT...COULD SEE A SECONDARY HAIL
THREAT. THE MISSING ELEMENT IS A WELL DEFINED FOCUS FOR LOW LEVEL
CONVERGENCE...THUS WILL KEEP POPS IN THE SLIGHT TO LOW CHANCE
CATEGORY AS ANY CONVECTION THAT DOES DEVELOP IS EXPECTED TO BE
SCATTERED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU JUN 27 2013
INSTABILITY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS NE
SECTIONS OF THE CWFA ON FRIDAY...AS AN UPPER LEVEL SHORT WAVE PIVOTS
SOUTHWARD ACROSS WI. POTENTIAL EXITS FOR SOME OF THE STRONGER
STORMS TO PRODUCE SOME HAIL. BETTER CHANCES FOR MAINLY SHOWERS ON
SATURDAY...AS ANOTHER VORT SWEEPS MORE DIRECTLY ACROSS THE REGION.
THINGS QUIET DOWN THROUGH TUESDAY...AS HIGH PRESSURE BUILD IN.
SLIGHT/LOW POP CHANCES RETURN TO THE FCST FOR TUE NIGHT AND WED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1148 PM CDT WED JUN 26 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE REST OF THE NIGHT. THERE
IS A LOW PROBABILITY OF FOG FORMATION DUE TO LIGHT WINDS AND
LINGERING MOISTURE. CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN
THE TAFS BEYOND A PERIOD OF OVERNIGHT VISIBILITIES IN THE RANGE OF 5SM
TO 6SM. THURSDAY SHOULD REMAIN VFR WITH WINDS INCREASING TO 10 TO
20 KTS AND GUSTY FOR A PERIOD IN THE AFTERNOON. THERE IS A LOW
POTENTIAL FOR THUNDERSTORMS...ESPECIALLY ALONG AND EAST OF THE DBQ
AND MLI TERMINALS...BUT THIS POSSIBILITY IS TOO LOW TO INCLUDE IN
THE TAFS AT THIS TIME.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...14
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1204 AM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1148 PM CDT WED JUN 26 2013
MID AND UPPER LEVEL SUBSIDENCE ASSOCIATED WITH A PASSING MID LEVEL
SHORTWAVE RIDGE AND RIGHT EXIT REGION OF A 90 KT UPPER LEVEL JET
MOVING THROUGH THE NORTHERN PLAINS AND UPPER MS VALLEY HAS
SQUELCHED CONVECTION OVER THE FORECAST AREA THIS EVENING.
CONSIDERING THIS...AND A LACK OF LOW LEVEL CONVERGENCE...SHOWERS
AND THUNDERSTORMS ARE NOT EXPECTED THROUGH THE REST OF TONIGHT.
SATELLITE IMAGES SHOW AN AREA OF CI UPSTREAM...WHICH SHOULD HELP
LIMIT FOG FORMATION WHICH WOULD OTHERWISE BE MORE FAVORABLE GIVEN
WEAK PRESSURE GRADIENT...LIGHT WINDS AND LINGERING HIGH DEWPOINTS
AND MOIST SURFACE CONDITIONS FROM RECENT RAINS. THUS...HAVE KEPT
FOG OUT OF THE FORECAST WITH ONLY MINOR TWEAKS IN EVENING UPDATES.
&&
.SYNOPSIS...
ISSUED AT 334 PM CDT WED JUN 26 2013
18Z SFC ANALYSIS HAS THE REMNANTS OF A MESO HIGH AT KDBQ AND A MESO
LOW BETWEEN KSQI AND KFEP. AN OUTFLOW BOUNDARY FROM THE MCS RAN FROM
LAKE MICHIGAN THROUGH CENTRAL ILLINOIS AND THEN TO NEAR KMXO. THE
SYNOPTIC COLD FRONT RAN FROM NEAR KMSP...TO KDSM...TO KFNB. AHEAD OF
THE SYNOPTIC FRONT SEVERAL WEAK TROFS/BOUNDARIES WERE ACROSS EASTERN
IOWA AND MISSOURI. DEW POINTS WERE IN THE 70S WITH 60S OVER THE
GREAT LAKES AND BEHIND THE COLD FRONT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 334 PM CDT WED JUN 26 2013
DIURNAL CONVECTION HAS FIRED ALONG A THETA E GRADIENT IN CENTRAL
IOWA AND ALONG A PRE-FRONTAL TROF. RAP TRENDS BRING THIS FEATURE
INTO THE WESTERN CWFA LATE THIS AFTERNOON BEFORE WEAKENING THE
THETA E GRADIENT. THUS THE NEW STORMS THAT HAVE DEVELOPED JUST WEST
OF THE CWFA ARE EXPECTED TO MOVE INTO THE WESTERN CWFA DURING THE
LATE AFTERNOON HOURS AND THEN SLOWLY DISSIPATE WITH SUNSET.
AHEAD OF THIS CONVECTION...ISOLATED SHOWERS AND STORMS ARE EXPECTED
TO DEVELOP DURING PEAK HEATING THAT WILL ALSO SLOWLY DISSIPATE WITH
SUNSET.
THE SYNOPTIC COLD FRONT WILL MOVE THROUGH THE CWFA TONIGHT DROPPING
DEW POINTS ABOUT 5 TO 7 DEGREES. WINDS ARE EXPECTED TO BE FAIRLY
LIGHT AND GIVEN THE WET GROUND IN SOME AREAS THERE IS A POTENTIAL
FOR SOME FOG DEVELOPMENT AFTER MIDNIGHT. THIS WILL HAVE TO BE
WATCHED TO SEE HOW IT WILL EVOLVE.
QUIET AND DRY CONDITIONS WILL BE SEEN THURSDAY MORNING ACROSS THE
AREA WHILE AN UPPER LOW MOVES INTO THE NORTHERN GREAT LAKES. DAY
TIME HEATING COMBINED WITH SLIGHTLY COOLER AIR ALOFT SHOULD ALLOW
NEW CONVECTION TO DEVELOP DURING THE AFTERNOON. THE LOWER MOISTURE
LEVELS IN THE ATMOSPHERE AND NORTHWEST FLOW SHOULD RESULT IN THE
CONVECTION BEING ISOLATED TO SCATTERED IN NATURE. ..08..
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 334 PM CDT WED JUN 26 2013
THURSDAY NIGHT AND FRIDAY...AS NORTHWESTERLY STEERING FLOW TAKES
OVER WITH UPPER RIDGE RETROGRADE...DIGGING UPPER WAVE INTO THE
NORTHWESTERN GRT LKS WILL CONNECT WITH TROF INTO THE CENTRAL PLAINS
FOR CONTINUED ISOLATED TO WDLY SCTRD SHOWER/STORM THREAT INTO MID
THU EVENING. BUT BEST FORCING AND CONVERGENCE TO REMAIN JUST TO THE
NORTHEAST AND SOUTHWEST OF THE DVN CWA. WILL EXTEND LOW CHC POPS IN
THE FAR EAST AND MAINTAIN ONGOING POPS IN THE SOUTHWESTERN CWA
THROUGH 03Z FRI. AFTER TROF EMBEDDED IN NW STEERING FLOW
PASSES...EXPECT SOME CLEARING AND COOLER CONDITIONS INTO EARLY FRI
MORNING WITH LOWS WELL DOWN INTO THE 60S...POSSIBLY SOME LOWER 60S
NORTH OF I80. LARGE UPPER CYCLONE COMPLEX TO THEN CONTINUE TO SETTLE
ACRS THE HEART OF THE GRT LKS ON FRI. ASSOCIATED VORT SPOKE ALOFT
AND MID LEVEL COOL POOL TO INDUCE DEEP STEEP LAPSE RATES AND A
INSTABILITY SHOWER SET UP ACRS MN INTO WI AND IL. SOME POTENTIAL FOR
THUNDERSTORMS WITH VERTICAL THERMODYNAMIC PROFILES SUPPORTIVE OF
HAIL IF ENHANCED UPDRAFTS CAN MAINTAIN. THIS ACTIVITY MORE LIKELY
FRIDAY AFTERNOON ACRS THE NORTHEASTERN THIRD OF THE DVN CWA AND WILL
ADJUST POPS ACCORDINGLY. DESPITE INCOMING COOLER AIR INFLUX/
ADVECTION...DEEP MIXING PROFILES UP TO H8 MB STILL TO BOOST TEMPS
INTO THE LOW TO MID 80S WHILE SFC DPTS DRY-DOWN MIX INTO THE LOWER
60S TO UPPER 50S...MAYBE LOWER THAN GUIDANCE SUGGESTS INTO THE MID
50S. BREEZY NORTHWEST WINDS AS WELL IN THIS SCENARIO OF 15 TO 20+
MPH. TIGHTENING CYCLONIC FLOW ALOFT MAY KEEP SHOWERS PECULATING WELL
INTO FRI EVENING BEFORE NOCTURNAL PROCESSES TAKE OVER. EVEN WITH
CLOUD DEBRIS...STILL A COOLER NIGHT WITH WIDESPREAD LOWS IN THE LOW
TO MID 60S.
SATURDAY AND SUNDAY...UNSTABLE VERTICAL PROFILES UNDER ONGOING
CYCLONIC FLOW AND ANOTHER INCOMING VORT SPOKE MAY PRODUCE MORE
WIDESPREAD SHOWERS AND A FEW STORMS/FURTHER TO THE WEST/THEN ON
FRIDAY. CANADIAN LLVL RIDGE AXIS DUMPING DOWN TO THE WEST OF THE AREA
ACRS THE PLAINS. FCST SOUNDING SUGGEST ANOTHER DAY OF DEEP MIXING...
BUT CONTINUED LLVL COOL POOL INFLUX AS WELL AS SHOWERS/CLOUDS WILL
HAVE A BETTER SHOT TO KEEP TEMPS IN THE 70S. CLEAR OUT SAT NIGHT AS
LARGE STOUT CANADIAN HIGH TAKES GRIP OF THE UPPER MIDWEST AND COULD
FOSTER WIDESPREAD LOWS WELL DOWN IN THE 50S BY EARLY SUNDAY MORNING.
HIGH PRESSURE TO THEN TO MIGRATE TOWARD THE GRT LKS ON SUNDAY...WHILE
ALOFT DEEP LONG WAVE TROF EXTENDS TO THE GULF ALONG AND EAST OF THE
MS RVR VALLEY. APPEARS LESSENING CHANCE OF SHOWERS SUNDAY AND
BOUNDARY LAYER NORTHEASTERLY FETCH AGAIN TO POSSIBLY KEEP TEMPS IN
THE 70S FOR HIGHS. SUNDAY NIGHT SEASONABLY COOL AND WELL DOWN IN THE
50S ALONG AND NORTH OF I80.
MONDAY THROUGH NEXT WEDNESDAY...LONG RANGE SIGNALS SUGGEST A GENERAL
BLOCKED PATTERN WITH BOOKEND RIDGES ON THE COASTS AND MID CONUS L/W
TROFFINESS PERSISTING THROUGH WED. BUT THEY ALSO SUGGEST IT TO START
TO MODIFY AND BREAK DOWN THE L/W TROF FEATURE AFTER TUE. THUS IN
GENERAL...BELOW NORMAL TEMPS LOOK TO CONTINUE IN THE VCNTY OF THIS
UPPER TROF..AS WELL AS ALMOST A DAILY THREAT OF POP UP SHOWERS AND
A FEW STORMS. BETTER CHANCES OFF THOUGH TO THE SOUTHEAST OF THE DVN
CWA IN VCNTY OF UPPER LOW MON INTO TUE. ..12..
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1148 PM CDT WED JUN 26 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE REST OF THE NIGHT. THERE
IS A LOW PROBABILITY OF FOG FORMATION DUE TO LIGHT WINDS AND
LINGERING MOISTURE. CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN
THE TAFS BEYOND A PERIOD OF OVERNIGHT VISIBILITIES IN THE RANGE OF 5SM
TO 6SM. THURSDAY SHOULD REMAIN VFR WITH WINDS INCREASING TO 10 TO
20 KTS AND GUSTY FOR A PERIOD IN THE AFTERNOON. THERE IS A LOW
POTENTIAL FOR THUNDERSTORMS...ESPECIALLY ALONG AND EAST OF THE DBQ
AND MLI TERMINALS...BUT THIS POSSIBILITY IS TOO LOW TO INCLUDE IN
THE TAFS AT THIS TIME.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS WICHITA KS
956 PM CDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 955 PM CDT FRI JUN 28 2013
INCREASING 700-600MB CONVERGENCE IN RESPONSE TO SUBTLE SHORTWAVE
ENERGY RACING SOUTH ACROSS THE MIDWEST MAY RESULT IN A FEW SHOWERS
AND PERHAPS EVEN A THUNDERSTORM OVER PORTIONS OF CENTRAL AND
SOUTH-CENTRAL KS BETWEEN ABOUT 2-9AM OVERNIGHT-SAT MORNING.
LATEST RUC AND HRRR WOULD SUGGEST THE BEST POTENTIAL GENERALLY
WEST/SOUTHWEST OF A LINE EXTENDING FROM RUSSELL TO HUTCHINSON TO
WELLINGTON. HAVE UPDATED THE FORECAST ACCORDINGLY.
ADK
&&
UPDATE ISSUED AT 632 PM CDT FRI JUN 28 2013
UPDATED THE AVIATION SECTION BELOW FOR THE 00Z TAFS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 107 PM CDT FRI JUN 28 2013
HIGHS THROUGH THE PERIOD ARE EXPECTED TO REMAIN
5-10 DEGREES BELOW NORMAL WITH VALUES IN THE 80S WHILE BREEZY
NORTHERLY WINDS ARE ANTICIPATED DURING THE AFTERNOON/EARLY EVENING
HOURS. LOW TEMPERATURES MAY BE AROUND 10 DEGREES BELOW NORMAL WITH
LOW-LYING AREAS FALLING INTO THE MID AND UPPER 50S THROUGH THE
PERIOD.
.LONG TERM...(WEDNESDAY THROUGH FRIDAY)
ISSUED AT 107 PM CDT FRI JUN 28 2013
LIGHT EAST TO SOUTHEAST WINDS WILL RETURN TO THE CENTRAL PLAINS TOWARD
THE MIDDLE OF THE WEEK WHILE BOTH THE GFS/ECMWF SUGGEST A WEAK
MID/UPPER TROUGH WILL ROUND THE RIDGE AND RESIDE ACROSS THE
CENTRAL CONUS. THIS WILL LEAD TO INCREASING CHANCES FOR SHOWERS
AND THUNDERSTORMS WHILE TEMPERATURES REMAIN BELOW CLIMATOLOGICAL
NORMALS.
MWM
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 632 PM CDT FRI JUN 28 2013
QUIET VFR CONDITIONS ANTICIPATED FOR ALL TAF SITES THE NEXT 24
HOURS. SOMEWHAT GUSTY NORTHERLY WINDS WILL SLACKEN QUITE A BIT BY
01-02Z THIS EVENING...WITH NORTH/NORTHWEST WINDS INCREASING AGAIN
BY LUNCHTIME SATURDAY ALL AREAS...ALONG WITH FEW-SCT CLOUDS AROUND
5000-7000 FT AGL.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 67 89 63 84 / 10 0 0 10
HUTCHINSON 65 89 61 84 / 10 0 10 10
NEWTON 64 87 60 83 / 0 0 0 10
ELDORADO 65 86 60 82 / 10 0 0 10
WINFIELD-KWLD 65 89 61 84 / 10 0 10 10
RUSSELL 64 89 59 84 / 10 10 10 0
GREAT BEND 64 90 60 84 / 10 10 10 0
SALINA 66 88 61 84 / 0 0 0 10
MCPHERSON 65 89 60 84 / 0 0 10 10
COFFEYVILLE 66 86 62 81 / 10 0 0 10
CHANUTE 64 84 60 81 / 10 0 0 10
IOLA 64 83 60 80 / 0 0 0 10
PARSONS-KPPF 64 85 60 81 / 10 0 0 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
130 PM MDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1053 AM MDT THU JUN 27 2013
JUST COMPLETED AN UPDATE. MAIN CHANGES WERE TO RAISE HIGH TEMPERATURES...
ESPECIALLY IN THE SOUTHEAST PORTION OF THE AREA...AND TO ISSUE A
RED FLAG WARNING FOR THE SOUTHERN PORTION OF THE AREA...REFER TO
FIRE WEATHER SECTION BELOW. TEMPERATURES ARE RISING FAIRLY RAPIDLY
AND WITH THE STRONGER COLD AIR ADVECTION NOT EXPECTED TO ARRIVE
UNTIL UNTIL LATER...RAISED THE MAXES. GUSTY NORTH WINDS SPREADING
OVER THE AREA AND WOULD EXPECT THEM TO STAY ABOUT THE SAME OR GET
A LITTLE STRONGER BASED ON AREA VWPS AND WINDS UPSTREAM.
PLAN ON KEEPING THE FORECAST DRY THROUGH TONIGHT. MAIN LOW LEVEL
CONVERGENCE WILL LIE SOUTH AND EAST OF THE AREA BY 21Z. ALSO NOT
A LOT OF MID LEVEL LIFT AROUND AND MAYBE EVEN DOWNWARD
MOTION/RISING HEIGHTS BEHIND SHORTWAVE TROUGH THAT IS CURRENTLY
MOVING ACROSS THE AREA. SATELLITE AND UPPER AIR ANALYSIS SHOW A
DRYING AT MID LEVELS WITH A RATHER STRONG EML MOVING IN AND 700 MB
TEMPERATURES OF PLUS 15 TO 17. SO EXPECT TO STAY CAPPED WITH
PRECIPITATION DEVELOPING TO THE SOUTH AND EAST OF THE AREA. THE
LATEST HRRR CAPTURED THAT SCENARIO WELL.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 329 AM MDT THU JUN 27 2013
THE UPPER RIDGE CONTINUES TO AMPLIFY OVER THE WESTERN UNITED
STATES THROUGH FRIDAY WITH THE UPPER FLOW OVER THE CENTRAL HIGH
PLAINS BECOMING NORTH NORTHWESTERLY BY SATURDAY AND EVEN MORE
NORTHERLY BY EARLY SUNDAY MORNING. SEVERAL POORLY DISCERNED WAVES
ROTATE AROUND THE PERIPHERY OF THE UPPER HIGH CENTER THAT
RETROGRADES MORE WESTERLY DURING THIS PERIOD. THE VORTICITY MAXES
SHOWING UP IN THE MODEL SOLUTIONS APPEAR TO BE DIURNALLY DRIVEN
CONVECTIVE FEEDBACK ARTIFACTS THAT STAY CONFINED MAINLY TO THE
AREAS OF HIGHER TERRAIN ALONG THE ROCKIES AND FRONT RANGE EACH
AFTERNOON AND EVENING.
A COOLER AREA OF SURFACE HIGH PRESSURE BEHIND A WEAK COLD FRONT
SLIDES THROUGH THE NORTHERN HIGH PLAINS AND INTO THE CENTRAL
HIGH PLAINS TONIGHT AND EARLY FRIDAY FOR SOME MINOR MODERATION OF
HOT TEMPERATURES. RETURN FLOW WILL BRING ADDITIONAL MOISTURE INTO
THE REGION...BUT WILL BE LACKING A GOOD GULF CONNECTION NEEDED FOR
WIDESPREAD PRECIPITATION. THE FRONT THAT PUSHES UP ALONG THE FRONT
RANGE APPEARS TO MOVE EASTWARD OVER THE FORECAST AREA BY FRIDAY
EVENING...PROVIDING A NEAR SURFACE CONVERGENT ZONE FOR
THUNDERSTORMS DEVELOPMENT TO FOCUS ON. EXPECT ONLY ISOLATED TO
SCATTERED THUNDERSTORMS ACROSS MAINLY THE WESTERN SECTIONS OF THE
FORECAST AREA FRIDAY EVENING WITH OTHERWISE DRY CONDITIONS THROUGH
THE SHORT TERM PORTION OF THE FORECAST. ADDITIONAL MODERATION OF
TEMPERATURES WILL OCCUR ON SATURDAY AFTER THE FRONTAL BOUNDARY PUSHES
BACK UP AGAINST THE FRONT RANGE FRIDAY NIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 129 PM MDT THU JUN 27 2013
FRIDAY NIGHT-SUNDAY...HR RIDGE WILL CONTINUE TO DOMINATE THE PATTERN
ACROSS THE AREA WITH ITS CENTER REMAINING AROUND THE FOUR CORNERS
AREA THROUGH THE PERIOD AND NORTHERLY FLOW ALOFT PREVAILING ACROSS
THE CWA. WITH EXPECTED POSITION OF H5 TROUGH LEADING TO A FEW
PERIODS OF LARGE SCALE FORCED ASCENT AND EASTERLY FLOW EXPECTED
THROUGH MUCH OF THE PERIOD ANTICIPATE PERIODS OF DIURNALLY DRIVEN
THUNDERSTORMS EACH EVENING. GIVEN NORTHERLY FLOW ALOFT AND
INSTABILITY AND ELEVATED THETA E RIDGE STAYING ACROSS WESTERN
PORTIONS OF THE CWA DO NOT THINK STORMS WILL MAKE A GREAT EASTWARD
PUSH THROUGH THE PERIOD...WITH AREA IMPACTED DIMINISHING THROUGH
SUNDAY AS COOLER AIR SETTLES IN.
TEMPERATURES WILL COOL THROUGH THE PERIOD AS SFC HIGH BECOMES
CENTERED OVER THE CWA BY SUNDAY. MAY SEE TEMPS STRUGGLE TO CLIMB OUT
OF THE LOWER 80S BY THAT POINT. ALSO LOWERED MIN TEMPS SEVERAL
DEGREES THROUGH THE PERIOD TO ACCOUNT FOR EXPECTED COOLER AIRMASS
DURING THE PERIOD.
IN THE EXTENDED....UPPER FLOW PATTERN AMPLIFIES SIGNIFICANTLY BY THE
FIRST OF THE WEEK AS MEAN LAYER RIDGE BUILDS/STRENGTHENS ACROSS THE
WESTERN CONUS AND MID/UPPER LEVEL LOW EVOLVES OVER THE EASTERN
CONUS. THIS MID/UPPER LOW WILL RETROGRADE WESTWARD BEFORE WEAKENING
AND SHIFTING BACK EASTWARD LATE IN THE EXTENDED PERIOD.
MEANWHILE...A BROAD/WEAK TROUGH DEVELOPS OVER THE NORTHERN PLAINS
AND EXTENDS WESTWARD TO THE CENTRAL AND NORTHERN ROCKIES.
EASTERLY/SOUTHEASTERLY LOW LEVEL FLOW WILL GRADUALLY BRING HIGHER
THETA-E AIR INTO THE AREA DURING THIS PERIOD. THE MORE SIGNIFICANT
PUSH OF LOW LEVEL MOISTURE WILL LIKELY HOLD OFF UNTIL MID WEEK WHEN
AFOREMENTIONED UPPER TROUGH DEVELOPS OVER THE NORTHERN PLAINS
RESULTING IN STRENGTHENING OF BOTH THE LEE SIDE TROUGH AND
SOUTHEASTERLY SURFACE FLOW.
WHILE CONFIDENCE OF MEETING OR EXCEEDING CLIMATOLOGICALLY NORMAL POP IS
RELATIVELY HIGH THROUGH THE PERIOD GIVEN LOW HEIGHT ANOMALIES AND
FAVORED NORTHWESTERLY UPPER FLOW...DETERMINING WHICH DAY OR DAYS MAY
NECESSITATE HIGHER POPS IS DIFFICULT. MEDIUM RANGE MODELS HAVE NOT
BEEN CONSISTENT IN PLACEMENT/TIMING OF SMALL SCALE FEATURES EMBEDDED
WITHIN THE NORTH/NORTHWEST FLOW ALOFT AS WELL AS UNCERTAINTY ON
LARGER SCALE PATTERN TOWARD THE END OF THE EXTENDED PERIOD GIVEN THE
GROWING SPREAD AMONG GFS ENSEMBLE MEMBERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1139 AM MDT THU JUN 27 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. COLD FRONT IS
MOVING THROUGH THE AREA. WINDS WILL BE GUSTY UNTIL EARLY THIS
EVENING. WINDS THEN BECOME LIGHT AND VARIABLE THROUGH THE REST OF
THE PERIOD. EXPECT ALL THUNDERSTORMS TO STAY TO THE EAST OF THE
AREA.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING UNTIL 7 PM MDT /8 PM CDT/ THIS EVENING FOR
KSZ013>016-027>029-041-042.
CO...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ253-254.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JRM/BRB
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS WICHITA KS
1246 PM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1245 PM CDT THU JUN 27 2013
THUNDERSTORM DEVELOPMENT IS STILL ON TRACK FOR THIS
AFTERNOON...ALTHOUGH HIGHER RESOLUTION GUIDANCE HAS CONTINUED TO
GIVE AN EARLIER INITIATION TIME OVER CENTRAL KANSAS THAN OTHER
MESO-SYNOPTIC MODELS. THE QUESTION IS...1. WHERE WILL THE OUTFLOW
BOUNDARY FROM MORNING CONVECTION OVER NORTHEAST KANSAS SET UP.
2.HOW QUICK WILL THIS ACTIVITY ACTUALLY DEVELOP...AND 3. ITS SPEED
ACROSS THE AREA. THE LAST 3-4 RUNS OF THE HRRR CONTINUE TO DEVELOP
A LINE NORTHEAST OF RUSSELL...DIVING THE LINE SOUTHEASTWARD
ACROSS THE AREA THROUGH THE LATE AFTERNOON HOURS (INITIATION
AROUND 19-20Z) AND INTO THE EARLIER EVENING. THE HRRR HAS THE
ACTIVITY EXITING INTO OKLAHOMA/MISSOURI BY EVENING (01Z)...WHILE
THE NAM IS JUST A BIT SLOWER. ALTHOUGH THE 12Z NAM DID SPEED UP
THE PROPAGATION SLIGHTLY. WILL CONTINUE TO WATCH...BUT DO THINK
WITH MAXIMUM HEATING AND TEMPS ALREADY AT NEARLY 100 AT
NOON...CONVECTION COULD BEGIN IN THE NEXT 2-3 HOURS. MAIN RISKS
REMAIN THE SAME AS EARLIER FORECASTER MENTIONED. NO LARGE CHANGES
TO THE FORECAST.
BILLINGS
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 332 AM CDT THU JUN 27 2013
TODAY & TONIGHT:
HIGHLIGHTS:
1) CONTINUANCE OF HEAT ADVISORY FOR MOST AREAS UNTIL 8 PM CDT FOR MOST
AREAS. (THE EXCEPTIONS BEING RUSSELL...BARTON & LINCOLN COUNTIES.)
2) "HIGH-END" SVR (+)TSRA FROM LATE THIS AFTERNOON THRU LATE TONIGHT.
TODAY:
ULTRA HIGH OCTANE LWR-DECK FUEL POOLING ALONG & SE OF A WEAK NEARLY
STATIONARY FRONT EXTENDING FROM ERN NEBRASKA TO SW KS WILL PRODUCE
ANOTHER OPPRESSIVELY HOT & HUMID WEATHER FOR ALL OF KICT COUNTRY. HEAT
ADVISORY IN EFFECT FOR ALL OF CENTRAL...SC & MOST OF CNTRL KS REMAINS
IN EFFECT TIL 8 PM.
LATE THIS AFTERNOON-LATE TONIGHT:
NO DOUBT...THE FOCUS SHIFTS TO SIGNIFICANT SVR (+)TSRA THAT`LL BREAK
OUT OVER ALL AREAS. AN INTENSE CYCLONE THAT`LL INVADE THE GREAT LAKES
WILL FORCE A STRONG & OBVIOUSLY MASSIVE MID-UPR HIGH COVERING MOST OF
THE WRN CONUS SLIGHTLY W. THIS WOULD RESULT IN THE WRN PERIPHERY OF A
STRONG UPR-DECK FLOW TO SPREAD SW OVER ERN KS. THIS...IN TURN...WOULD
ENABLE A FAIRLY STRONG COLD FRONT TO SURGE SE ACROSS KS INTO AN ULTRA
HIGH OCTANE MOIST LWR-DECK ENVIRONMENT COVERING THE CNTRL & ERN PLAINS.
(SFC DWPTS: LWR-MID 70S. 925MB: ~20C(!). 850MB: 18-20C. SBCAPES REACH
~6.500J/KG OVER ERN KS LATE THIS AFTERNOON & THIS EVENING & WITH 6KM
SHEAR INCREASING TO 40-45KTS & VEERING MARKEDLY WITH TIME SVR (+)TSRA
ARE A CERTAINTY FOR MOST OF KICT. AM UPPING THE HAIL & DAMAGING WIND
ANTE TO NEARLY TENNISBALL-SIZED & 60-80 MPH RESPECTIVELY WITH THE HAIL
THREAT GREATEST LATE THIS AFTERNOON & EARLY THIS EVENING WITH A
TRANSITION TO DAMAGING WINDS AS COMPLEX EVOLVES INTO AN MCS. GIVEN THE
STRENGTH OF THE UPR-DECK NW FLOW THE COLD FRONT SHOULD STILL EXIT SE
KS EARLY FRI MORNING.
THIS WEEKEND:
A FEW POST-FRONTAL -SHRA/-TSRA MAY STILL FESTER OVER SE KS EARLY FRI
MORNING. THERE`LL BE VERY NICE WEATHER THE REMAINDER OF THE WEEKEND AS
HIGH PRESSURE SLOWLY BUILDS S/SE ACROSS THE WRN PLAINS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 322 AM CDT THU JUN 27 2013
THE NEXT CHANCE FOR -TSRA SHOULD ARRIVE MON NGT WITH CHANCES GRADUALLY
INCREASING TUE NGT & WED WHEN THE NEXT COLD FRONT IS SCHEDULED TO MOVE
TOWARD CNTRL KS. THE BEHAVIOR OF THE FRONT WILL REQUIRE GRADUALLY
INCREASING ATTENTION AS MID-WEEK APPROACHES AS DIFFERENCES BETWEEN THE
MID-RANGE MODELS EXIST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1245 PM CDT THU JUN 27 2013
THE MAIN AVIATION FORECAST CONCERNS ARE THE THUNDERSTORM CHANCES
THIS AFTERNOON AND EVENING AT ALL TERMINALS.
UNTIL CONVECTION DEVELOPS...TERMINALS WILL REMAIN VFR WITH
RELATIVELY LIGHT SOUTHERLY WINDS. AS THE SURFACE LOW BEGINS TO
MOVE SOUTHEAST...CONVECTION WILL BEGIN TO DEVELOP AND IT IS
EXPECTED TO FORM NORTHEAST OF KRSL AND MOVE SOUTHEAST ACROSS ALL
TERMINALS. CURRENT THINKING IS TIMING WILL BEGIN AT 20-21Z FOR
KRSL AND MOVE SOUTHEAST TO KCNU BY 00Z FOR MAIN LINE. THERE MAYBE
SOME GIVE AND TAKE WITH THAT TIMING...BUT THE LATEST HIGH
RESOLUTION GUIDANCE...HRRR/RAP HAVE BEEN CONSISTENT FOR THE LAST
FEW RUNS WITH THAT TIMING.
DURING THE CONVECTION HEAVY THUNDERSTORMS ARE POSSIBLE WITH LARGE HAIL
AND STRONG WINDS. GUSTS OF 60MPH OR GREATER ARE POSSIBLE. HEAVY
RAIN WILL CAUSE VISIBILITIES TO BE REDUCED AND CEILINGS TO DROP.
HAVE INCLUDED A TEMP GROUP FOR MODERATE THUNDERSTORMS DROPPING
INTO MVFR...BUT COULD SEE IFR TO LIFR CONDITIONS IN THE HEAVIEST
OF STORMS...AT LEAST BRIEFLY.
AFTER THE STORMS PASS...BEHIND THE COLD FRONT WINDS WILL BE NORTH
TO NORTHEASTERLY WITH VFR CONDITIONS EXPECTED.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 104 73 95 69 / 20 50 10 10
HUTCHINSON 104 71 95 67 / 30 40 10 10
NEWTON 103 71 94 67 / 30 50 10 10
ELDORADO 102 71 94 66 / 20 50 10 10
WINFIELD-KWLD 103 74 95 69 / 10 40 20 10
RUSSELL 103 68 96 65 / 30 20 0 10
GREAT BEND 105 69 95 66 / 30 30 0 10
SALINA 103 70 95 67 / 40 40 0 10
MCPHERSON 104 70 95 67 / 40 40 10 10
COFFEYVILLE 99 74 94 68 / 10 50 20 10
CHANUTE 99 72 93 66 / 10 50 20 10
IOLA 98 71 92 65 / 10 60 20 10
PARSONS-KPPF 98 73 93 66 / 10 50 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ048>053-067>072-
082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1141 AM MDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1053 AM MDT THU JUN 27 2013
JUST COMPLETED AN UPDATE. MAIN CHANGES WERE TO RAISE HIGH TEMPERATURES...
ESPECIALLY IN THE SOUTHEAST PORTION OF THE AREA...AND TO ISSUE A
RED FLAG WARNING FOR THE SOUTHERN PORTION OF THE AREA...REFER TO
FIRE WEATHER SECTION BELOW. TEMPERATURES ARE RISING FAIRLY RAPIDLY
AND WITH THE STRONGER COLD AIR ADVECTION NOT EXPECTED TO ARRIVE
UNTIL UNTIL LATER...RAISED THE MAXES. GUSTY NORTH WINDS SPREADING
OVER THE AREA AND WOULD EXPECT THEM TO STAY ABOUT THE SAME OR GET
A LITTLE STRONGER BASED ON AREA VWPS AND WINDS UPSTREAM.
PLAN ON KEEPING THE FORECAST DRY THROUGH TONIGHT. MAIN LOW LEVEL
CONVERGENCE WILL LIE SOUTH AND EAST OF THE AREA BY 21Z. ALSO NOT
A LOT OF MID LEVEL LIFT AROUND AND MAYBE EVEN DOWNWARD
MOTION/RISING HEIGHTS BEHIND SHORTWAVE TROUGH THAT IS CURRENTLY
MOVING ACROSS THE AREA. SATELLITE AND UPPER AIR ANALYSIS SHOW A
DRYING AT MID LEVELS WITH A RATHER STRONG EML MOVING IN AND 700 MB
TEMPERATURES OF PLUS 15 TO 17. SO EXPECT TO STAY CAPPED WITH
PRECIPITATION DEVELOPING TO THE SOUTH AND EAST OF THE AREA. THE
LATEST HRRR CAPTURED THAT SCENARIO WELL.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 329 AM MDT THU JUN 27 2013
THE UPPER RIDGE CONTINUES TO AMPLIFY OVER THE WESTERN UNITED
STATES THROUGH FRIDAY WITH THE UPPER FLOW OVER THE CENTRAL HIGH
PLAINS BECOMING NORTH NORTHWESTERLY BY SATURDAY AND EVEN MORE
NORTHERLY BY EARLY SUNDAY MORNING. SEVERAL POORLY DISCERNED WAVES
ROTATE AROUND THE PERIPHERY OF THE UPPER HIGH CENTER THAT
RETROGRADES MORE WESTERLY DURING THIS PERIOD. THE VORTICITY MAXES
SHOWING UP IN THE MODEL SOLUTIONS APPEAR TO BE DIURNALLY DRIVEN
CONVECTIVE FEEDBACK ARTIFACTS THAT STAY CONFINED MAINLY TO THE
AREAS OF HIGHER TERRAIN ALONG THE ROCKIES AND FRONT RANGE EACH
AFTERNOON AND EVENING.
A COOLER AREA OF SURFACE HIGH PRESSURE BEHIND A WEAK COLD FRONT
SLIDES THROUGH THE NORTHERN HIGH PLAINS AND INTO THE CENTRAL
HIGH PLAINS TONIGHT AND EARLY FRIDAY FOR SOME MINOR MODERATION OF
HOT TEMPERATURES. RETURN FLOW WILL BRING ADDITIONAL MOISTURE INTO
THE REGION...BUT WILL BE LACKING A GOOD GULF CONNECTION NEEDED FOR
WIDESPREAD PRECIPITATION. THE FRONT THAT PUSHES UP ALONG THE FRONT
RANGE APPEARS TO MOVE EASTWARD OVER THE FORECAST AREA BY FRIDAY
EVENING...PROVIDING A NEAR SURFACE CONVERGENT ZONE FOR
THUNDERSTORMS DEVELOPMENT TO FOCUS ON. EXPECT ONLY ISOLATED TO
SCATTERED THUNDERSTORMS ACROSS MAINLY THE WESTERN SECTIONS OF THE
FORECAST AREA FRIDAY EVENING WITH OTHERWISE DRY CONDITIONS THROUGH
THE SHORT TERM PORTION OF THE FORECAST. ADDITIONAL MODERATION OF
TEMPERATURES WILL OCCUR ON SATURDAY AFTER THE FRONTAL BOUNDARY PUSHES
BACK UP AGAINST THE FRONT RANGE FRIDAY NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM MDT THU JUN 27 2013
INCREASING CONFIDENCE IN THE PATTERN FOR EARLY NEXT WEEK AS GUIDANCE
COMES INTO BETTER AGREEMENT. SYNOPTIC PATTERN WILL BE THAT OF A
STRENGTHENING AND INCREASING AMPLIFIED H5 TROUGH OVER THE SOUTHWEST
CONUS TRANSITIONING TO PACIFIC NORTHWEST WHILE AN UPPER LOW OVER THE
OHIO VALLEY DRIFTS WEST TO THE MID-MISSISSIPPI RIVER VALLEY. WHILE
SPECIFICS ACROSS MODELS DIFFER...THE GENERAL THEME IS A
NORTH-NORTHWEST FLOW AT UPPER LEVELS WITH SOUTHEASTERLY FLOW NEAR
THE SURFACE. A WEAK SHORTWAVE TROUGH MAKES ITS WAY AROUND THE RIDGE
ON SUNDAY INTO SUNDAY NIGHT WHICH MAY ENHANCE STORMS TRIGGERED OFF
THE FRONT RANGE AS THEY MOVE EAST INTO THE CENTRAL HIGH PLAINS.
MONDAY AND TUESDAY THE PATTERN BECOMES A LITTLE LESS CLEAR...THOUGH
BELIEVE THERE WILL BE SUFFICIENT INSTABILITY FOR STORMS TRIGGERED BY
WEAK SHORTWAVE TROUGHS MOVING SOUTH THROUGH THE HIGH PLAINS. ON
WEDNESDAY THE UPPER LOW OUT EAST WILL HAVE DRIFTED WEST INTO THE
NORTHERN PLAINS AND AN ASSOCIATED COLD FRONT WILL MAKE ITS WAY
THROUGH TRIGGERED WHAT LOOKS TO BE WIDESPREAD SHOWERS AND STORMS AND
BRINGING COOLER-THAN-NORMAL TEMPS BEHIND IT. SOME GOOD NEWS WITH
THIS PATTERN NO MATTER HOW THE PRECIP UNFOLDS IS THAT THERE WILL BE
NO FIRE WEATHER CONCERNS DURING THIS PERIOD THANKS TO SOMEWHAT MOIST
AIR /DEWPOINTS IN THE 50S/ AND OVERALL WEAK WINDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1139 AM MDT THU JUN 27 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. COLD FRONT IS
MOVING THROUGH THE AREA. WINDS WILL BE GUSTY UNTIL EARLY THIS
EVENING. WINDS THEN BECOME LIGHT AND VARIABLE THROUGH THE REST OF
THE PERIOD. EXPECT ALL THUNDERSTORMS TO STAY TO THE EAST OF THE
AREA.
&&
.FIRE WEATHER...
ISSUED AT 1053 AM MDT THU JUN 27 2013
RELATIVE HUMIDITIES OF LESS THAN 20 PERCENT AND TO NEAR 15 PERCENT
EXPECT TO OCCUR THIS AFTERNOON. QUESTION WILL BE IF THE WIND GUSTS
WILL GET HIGH ENOUGH FOR LONG ENOUGH IN CONCERT WITH THOSE LOW
RELATIVE HUMIDITIES. IT WILL BE CLOSE AND IF RELATIVE HUMIDITIES
DROP FASTER OR WINDS ARE STRONGER THEN WE WILL HIT IT. SO ISSUED A
RED FLAG WARNING FOR LOCATIONS ROUGHLY ALONG AND SOUTH OF A
FLAGLER TO GOODLAND TO HILL CITY LINE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING UNTIL 7 PM MDT /8 PM CDT/ THIS EVENING FOR
KSZ013>016-027>029-041-042.
CO...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ253-254.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JJM
AVIATION...BULLER
FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1105 AM MDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1053 AM MDT THU JUN 27 2013
JUST COMPLETED AN UPDATE. MAIN CHANGES WERE TO RAISE HIGH TEMPERATURES...
ESPECIALLY IN THE SOUTHEAST PORTION OF THE AREA...AND TO ISSUE A
RED FLAG WARNING FOR THE SOUTHERN PORTION OF THE AREA...REFER TO
FIRE WEATHER SECTION BELOW. TEMPERATURES ARE RISING FAIRLY RAPIDLY
AND WITH THE STRONGER COLD AIR ADVECTION NOT EXPECTED TO ARRIVE
UNTIL UNTIL LATER...RAISED THE MAXES. GUSTY NORTH WINDS SPREADING
OVER THE AREA AND WOULD EXPECT THEM TO STAY ABOUT THE SAME OR GET
A LITTLE STRONGER BASED ON AREA VWPS AND WINDS UPSTREAM.
PLAN ON KEEPING THE FORECAST DRY THROUGH TONIGHT. MAIN LOW LEVEL
CONVERGENCE WILL LIE SOUTH AND EAST OF THE AREA BY 21Z. ALSO NOT
A LOT OF MID LEVEL LIFT AROUND AND MAYBE EVEN DOWNWARD
MOTION/RISING HEIGHTS BEHIND SHORTWAVE TROUGH THAT IS CURRENTLY
MOVING ACROSS THE AREA. SATELLITE AND UPPER AIR ANALYSIS SHOW A
DRYING AT MID LEVELS WITH A RATHER STRONG EML MOVING IN AND 700 MB
TEMPERATURES OF PLUS 15 TO 17. SO EXPECT TO STAY CAPPED WITH
PRECIPITATION DEVELOPING TO THE SOUTH AND EAST OF THE AREA. THE
LATEST HRRR CAPTURED THAT SCENARIO WELL.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 329 AM MDT THU JUN 27 2013
THE UPPER RIDGE CONTINUES TO AMPLIFY OVER THE WESTERN UNITED
STATES THROUGH FRIDAY WITH THE UPPER FLOW OVER THE CENTRAL HIGH
PLAINS BECOMING NORTH NORTHWESTERLY BY SATURDAY AND EVEN MORE
NORTHERLY BY EARLY SUNDAY MORNING. SEVERAL POORLY DISCERNED WAVES
ROTATE AROUND THE PERIPHERY OF THE UPPER HIGH CENTER THAT
RETROGRADES MORE WESTERLY DURING THIS PERIOD. THE VORTICITY MAXES
SHOWING UP IN THE MODEL SOLUTIONS APPEAR TO BE DIURNALLY DRIVEN
CONVECTIVE FEEDBACK ARTIFACTS THAT STAY CONFINED MAINLY TO THE
AREAS OF HIGHER TERRAIN ALONG THE ROCKIES AND FRONT RANGE EACH
AFTERNOON AND EVENING.
A COOLER AREA OF SURFACE HIGH PRESSURE BEHIND A WEAK COLD FRONT
SLIDES THROUGH THE NORTHERN HIGH PLAINS AND INTO THE CENTRAL
HIGH PLAINS TONIGHT AND EARLY FRIDAY FOR SOME MINOR MODERATION OF
HOT TEMPERATURES. RETURN FLOW WILL BRING ADDITIONAL MOISTURE INTO
THE REGION...BUT WILL BE LACKING A GOOD GULF CONNECTION NEEDED FOR
WIDESPREAD PRECIPITATION. THE FRONT THAT PUSHES UP ALONG THE FRONT
RANGE APPEARS TO MOVE EASTWARD OVER THE FORECAST AREA BY FRIDAY
EVENING...PROVIDING A NEAR SURFACE CONVERGENT ZONE FOR
THUNDERSTORMS DEVELOPMENT TO FOCUS ON. EXPECT ONLY ISOLATED TO
SCATTERED THUNDERSTORMS ACROSS MAINLY THE WESTERN SECTIONS OF THE
FORECAST AREA FRIDAY EVENING WITH OTHERWISE DRY CONDITIONS THROUGH
THE SHORT TERM PORTION OF THE FORECAST. ADDITIONAL MODERATION OF
TEMPERATURES WILL OCCUR ON SATURDAY AFTER THE FRONTAL BOUNDARY PUSHES
BACK UP AGAINST THE FRONT RANGE FRIDAY NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM MDT THU JUN 27 2013
INCREASING CONFIDENCE IN THE PATTERN FOR EARLY NEXT WEEK AS GUIDANCE
COMES INTO BETTER AGREEMENT. SYNOPTIC PATTERN WILL BE THAT OF A
STRENGTHENING AND INCREASING AMPLIFIED H5 TROUGH OVER THE SOUTHWEST
CONUS TRANSITIONING TO PACIFIC NORTHWEST WHILE AN UPPER LOW OVER THE
OHIO VALLEY DRIFTS WEST TO THE MID-MISSISSIPPI RIVER VALLEY. WHILE
SPECIFICS ACROSS MODELS DIFFER...THE GENERAL THEME IS A
NORTH-NORTHWEST FLOW AT UPPER LEVELS WITH SOUTHEASTERLY FLOW NEAR
THE SURFACE. A WEAK SHORTWAVE TROUGH MAKES ITS WAY AROUND THE RIDGE
ON SUNDAY INTO SUNDAY NIGHT WHICH MAY ENHANCE STORMS TRIGGERED OFF
THE FRONT RANGE AS THEY MOVE EAST INTO THE CENTRAL HIGH PLAINS.
MONDAY AND TUESDAY THE PATTERN BECOMES A LITTLE LESS CLEAR...THOUGH
BELIEVE THERE WILL BE SUFFICIENT INSTABILITY FOR STORMS TRIGGERED BY
WEAK SHORTWAVE TROUGHS MOVING SOUTH THROUGH THE HIGH PLAINS. ON
WEDNESDAY THE UPPER LOW OUT EAST WILL HAVE DRIFTED WEST INTO THE
NORTHERN PLAINS AND AN ASSOCIATED COLD FRONT WILL MAKE ITS WAY
THROUGH TRIGGERED WHAT LOOKS TO BE WIDESPREAD SHOWERS AND STORMS AND
BRINGING COOLER-THAN-NORMAL TEMPS BEHIND IT. SOME GOOD NEWS WITH
THIS PATTERN NO MATTER HOW THE PRECIP UNFOLDS IS THAT THERE WILL BE
NO FIRE WEATHER CONCERNS DURING THIS PERIOD THANKS TO SOMEWHAT MOIST
AIR /DEWPOINTS IN THE 50S/ AND OVERALL WEAK WINDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 551 AM MDT THU JUN 27 2013
VFR CONDITIONS WITH MOSTLY SUNNY SKIES WILL PREVAIL AT BOTH GLD
AND MCK WITH SOUTHWEST WINDS TURNING TO THE NORTHWEST AND BECOMING
GUSTY THIS AFTERNOON WITH THE PASSAGE OF A FRONTAL BOUNDARY. WIND
SPEEDS WILL DIMINISH AFTER 00Z WITH WINDS TURNING TO THE EAST AND
THEN BECOMING LIGHT AND VARIABLE AFTER 07Z AS AN AREA OF HIGH
PRESSURE MOVES INTO THE REGION.
&&
.FIRE WEATHER...
ISSUED AT 1053 AM MDT THU JUN 27 2013
RELATIVE HUMIDITIES OF LESS THAN 20 PERCENT AND TO NEAR 15 PERCENT
EXPECT TO OCCUR THIS AFTERNOON. QUESTION WILL BE IF THE WIND GUSTS
WILL GET HIGH ENOUGH FOR LONG ENOUGH IN CONCERT WITH THOSE LOW
RELATIVE HUMIDITIES. IT WILL BE CLOSE AND IF RELATIVE HUMIDITIES
DROP FASTER OR WINDS ARE STRONGER THEN WE WILL HIT IT. SO ISSUED A
RED FLAG WARNING FOR LOCATIONS ROUGHLY ALONG AND SOUTH OF A
FLAGLER TO GOODLAND TO HILL CITY LINE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING UNTIL 7 PM MDT /8 PM CDT/ THIS EVENING FOR
KSZ013>016-027>029-041-042.
CO...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ253-254.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JJM
AVIATION...LOCKHART
FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
336 AM CDT THU JUN 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT THU JUN 27 2013
MID/UPPER LEVEL ISENTROPIC LIFT BEGINNING TO GENERATE VERY HIGH
BASED CONVECTION ALONG AND JUST NORTH OF THE NEBRASKA/SOUTH DAKOTA
BORDER EARLY THIS MORNING...GENERALLY NORTH OF MOST GUIDANCE HAS
SUGGESTED. 00Z 700MB OBSERVED TEMPS WERE RATHER MODEST IN THE LOWER
TEENS GIVEN 850MB TEMPS IN THE MID 20S C. 07Z SURFACE OBS SHOWED
INCREASING EVIDENCE OF A COLD FRONT FROM NORTHERN COLORADO TO NORTH
CENTRAL NEBRASKA.
UPPER FLOW ON TRACK TO TRANSITION FROM NEARLY WESTERLY TO NEARLY
NORTHERLY THROUGH TONIGHT...HELPING PUSH THE COLD FRONT SOUTHEAST
THROUGH THE REGION. TIMING FOR THE LOCAL AREA SHOULD BE IN THE MID
AFTERNOON TO EARLY MORNING HOURS...WITH MODEL SOUNDINGS SUGGESTING
VERY LITTLE MIXED LAYER CIN BY EARLY AFTERNOON /WHICH IS REASONABLE
GIVEN THE AFOREMENTIONED MODEST MID LEVEL TEMPS/ AND LARGE TO
EXTREME INSTABILITY WITH DEWPOINTS AROUND 70F AND TEMPS AGAIN NEAR
THE CENTURY MARK. CONFIDENCE IN LOW LEVEL CONDITIONS THOUGH NOT HIGH
IS INCREASING WITH TIME AS THE CURRENT CONVECTION REMAINS NORTH AND
SHOULD KEEP THE BOUNDARY LAYER UNMARRED BY RAIN/OUTFLOW. HEAT INDEX
VALUES IN THE 104-109 RANGE REMAIN ON TARGET AND WILL LEAVE THE HEAT
ADVISORY GOING AS-IS. NORTHWEST 500MB WINDS AROUND 45KT AND SOUTH TO
SOUTHWEST SURFACE WINDS WILL BRING DEEP LAYER SHEAR TO NEAR 50KT AND
COMBINE WITH THE INSTABILITY TO EASILY SUPPORT SUPERCELL STRUCTURES
WITH THE SHEAR VECTORS NEARLY PERPENDICULAR TO THE BOUNDARY. VERY
LARGE HAIL WOULD BE HIGH ON THE LIST OF CONCERN WITH INITIAL
CONVECTION WITH HIGH LCL HEIGHTS AND LIMITED LOW LEVEL SHEAR KEEPING
TORNADO RISK MORE IN CHECK. LOW CIN AND THE PRESENCES OF THE
PROGRESSIVE BOUNDARY SHOULD ALLOW STORMS TO CONGEAL TO MORE LINEAR
STRUCTURES WITH TIME AND LESSEN THE VERY LARGE HAIL CHANCES AFTER
EARLY EVENING. THE HIGH BASES AND POTENTIAL FOR DOWNDRAFT CAPE WELL
OVER 1000 J/KG WILL BRING DAMAGING WIND CONCERNS AS WELL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 313 AM CDT THU JUN 27 2013
QUITE A PATTERN CHANGE ON THE WAY FRIDAY INTO THE WEEKEND. COOL
CANADIAN HIGH PRESSURE SURGES SOUTHWARD UNDER NORTHERLY FLOW
ALOFT...DROPPING TEMPERATURES TO AROUND 90 FRIDAY WITH A FALL IN
TO THE 80S TO LOWER 80S BY THE END OF THE WEEKEND. HIGHLY
AMPLIFIED MERIDIONAL UPPER PATTERN CONTINUES THROUGH
TUESDAY...WITH ANOTHER PIECE OF ENERGY ROTATING THROUGH THE FLOW
INTO THE BACKSIDE OF THE UPPER EASTERN TROF...POSSIBLY RETROGRADING
IT BACK WESTWARD OVER THE CENTRAL PLAINS BY MID WEEK. THIS WOULD
BRING INCREASED CHANCE FOR PRECIP TOWARD WEDNESDAY AND WILL
REFLECT IN FORECAST. ALSO STILL A SIGNAL FOR AN IMPULSE TO MOVE
ACROSS THE EAST ON SUNDAY AND WILL CARRY SLIGHT CHANCE THEN AS
WELL. OTHERWISE A DRY AND BELOW NORMAL FORECAST FOR THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1145 PM CDT WED JUN 26 2013
CONFIDENCE IN THE CONVECTIVE FORECAST FOR TOMORROW IS LOW. MODELS
HAVE SHOWN LITTLE CONTINUITY WITH THE POSSIBILITY FOR ELEVATED
NOCTURNAL STORMS. THE RAP AND HRRR IN PARTICULAR BRING ELEVATED
STORMS FROM NEB INTO THE AREA EARLY IN THE DAY. IF THIS IS THE
CASE...THERE COULD BE SCT STORMS THROUGH MUCH OF THE DAY. UNTIL
ELEVATED STORMS BECOME APPARENT...THE FORECAST REMAINS
CONSERVATIVE THINKING THE HIGHEST PROB FOR STORMS WILL BE DURING
THE PEAK HEATING OF THE DAY. LOW LEVEL CONVERGENCE ALONG A WEAK
SFC BOUNDARY AND A VERY UNSTABLE AIRMASS COULD LEAD TO EXPLOSIVE
DEVELOPMENT IF MORNING SHOWERS AND THUNDERSTORMS DO NOT FORM.
ANTICIPATE VFR CONDITIONS TO PREVAIL UNLESS CONVECTION MOVES OVER
THE TERMINALS.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
FOR KSZ008-009-020>023-026-034>040-054>056-058-059.
&&
$$
SHORT TERM...65
LONG TERM...67
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1145 PM CDT WED JUN 26 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 348 PM CDT WED JUN 26 2013
TONIGHT THROUGH THURSDAY...
THE BROAD RIDGE CENTERED OVER THE ROCKY MOUNTAINS WILL CONTINUE TO
AMPLIFY NORTHWARD TONIGHT INTO TOMORROW AS THE MID LEVEL TROUGH
GRADUALLY DIGS FURTHER SOUTH ACROSS THE EASTERN U.S. ANOTHER MILD
NIGHT IS IN STORE FOR THE REGION AS SURFACE HIGH PRESSURE WEST OF
THE AREA TODAY PROGRESSES EAST OVER THE AREA TONIGHT...RESULTING IN
LIGHT WINDS VEERING TOWARD THE SOUTHEAST BY THURSDAY MORNING. THESE
WINDS COMBINED WITH WARM CONDITIONS ALREADY IN PLACE FROM AFTERNOON
TEMPERATURES SOARING INTO THE MID 90S TO AROUND 100 WILL LEAD TO
OVERNIGHT LOWS ONLY DROPPING INTO THE LOW/MID 70S.
MAIN FOCUS FOR THE SHORT TERM IS ON THE POTENTIAL FOR THUNDERSTORMS
TO DEVELOP ACROSS THE AREA ON THURSDAY. AS SURFACE LOW PRESSURE
MOVES IN ACROSS WESTERN KANSAS TONIGHT BEHIND THE PASSING SURFACE
HIGH...MODELS SHOW A WEAK BOUNDARY STRETCHING NORTHWARD INTO EASTERN
NEBRASKA. COULD SEE SOME THUNDERSTORMS DEVELOP EARLY THURSDAY
MORNING ACROSS EASTERN NEBRASKA NEAR THIS BOUNDARY WITH THE PRESENCE
OF SOME WEAK CONVERGENCE AS WELL AS A STRONG THERMAL GRADIENT IN
THAT REGION. UNCERTAINTY HOWEVER LIES IN THE TIMING OF THUNDERSTORM
INITIATION AND WHETHER THIS ACTIVITY WILL BE ABLE TO SUSTAIN ITSELF
INTO THE MORNING HOURS OR IF IT WILL WEAKEN THEN REDEVELOP NEAR THE
BOUNDARY IN THE AFTERNOON. WITH THE BUILDING MID-LEVEL
RIDGE...NORTHWESTERLY FLOW ALOFT WILL SHIFT ANY OF THIS ACTIVITY
SOUTHEASTWARD INTO EASTERN KANSAS. MODELS SHOW VERY FAVORABLE
CONDITIONS FOR ANY THUNDERSTORMS TO BECOME STRONG TO SEVERE...WITH
3500-5500J/KG OF MU CAPE...UPWARDS OF 45 TO 55 KTS OF 0-6KM BULK
SHEAR AND STEEP LOW LEVEL LAPSE RATES GENERALLY GREATER THAN 7C/KM.
MODEL SOUNDINGS SHOW CONDITIONS REMAINING CAPPED THROUGH EARLY
AFTERNOON WITH THE CAP ERODING AWAY BY MID AFTERNOON. SO ANY
ACTIVITY THAT DEVELOPS EARLIER IN THE DAY SHOULD REMAIN
ELEVATED...BUT ONCE STORMS BECOME SURFACE BASED IN THE AFTERNOON THE
CONDITIONS WILL BE PRIME FOR STRONG TO SEVERE THUNDERSTORMS. A
THREAT FOR LARGE HAIL WILL BE POSSIBLE INITIALLY WITH ANY SURFACE
BASED THUNDERSTORMS BUT SHOULD TRANSITION MORE OVER TO A SEVERE WIND
THREAT AS THE LOW TO MID LEVEL JET INCREASES OVER THE AREA AND MODEL
SOUNDINGS TAKE ON MORE OF A CLASSIC INVERTED V SHAPE.
THE OTHER MAIN THREAT FOR THURSDAY IS THE EXTREME HEAT THAT IS
EXPECTED. WITH SOUTH/SOUTHWESTERLY SURFACE WINDS DURING THE
DAY...WARM NOSE LOOKS TO STRETCH INTO CENTRAL AND EASTERN KANSAS
WITH 850MB TEMPERATURES PEAKING IN THE 25C-30C RANGE...ESPECIALLY
ACROSS CENTRAL AND EAST CENTRAL KANSAS. WITH THESE CONDITIONS MIXING
DOWN TO THE SURFACE...EXPECT AFTERNOON TEMPERATURES TO SOAR INTO THE
MID/UPPER 90S ACROSS EAST CENTRAL KANSAS AND INTO THE LOW 100S OVER
NORTH CENTRAL AND CENTRAL KANSAS. THE COOLEST CONDITIONS LOOK TO BE
ACROSS FAR NORTHEAST KANSAS WHERE INCREASED CLOUD COVER FROM THE
DEVELOPING THUNDERSTORMS SHOULD HINDER THE HEAT SOME WITH HIGHS
STAYING IN THE LOWER 90S. CONDITIONS ARE ALSO EXPECTED TO BE QUITE
HUMID AS DEWPOINT TEMPERATURES WILL LIKELY REMAIN IN THE UPPER 60S
TO LOWER 70S...RESULTING IN HEAT INDICES REACHING UPWARDS OF
105F-108F DEGREES. AS A RESULT...A HEAT ADVISORY HAS BEEN ISSUED FOR
MUCH OF NORTH CENTRAL...CENTRAL AND EAST CENTRAL KANSAS FOR THURSDAY
AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 348 PM CDT WED JUN 26 2013
FCST FOCUS ON THE EXTENDED ON TEMPS AND PRECIP CHCS WITH SLOW
EVOLUTION OF UPPER TROUGH.
INITIAL COLD FRONT WILL SWEEP THROUGH THE AREA THU NIGHT. LLJ AND
ASSOCIATED CONVERGENCE MAY LEAD TO CONTINUED ELEVATED STORM CHCS
ACROSS SOUTHEAST HALF OF THE CWA SO WILL KEEP THUNDER CHCS OVERNIGHT
ACROSS THAT AREA.
BY FRI...HIGH PRESSURE WILL SWEEP HUMID AIR SOUTH AND EXPECT
DEWPOINTS IN THE LOWER 60S ALONG WITH AIR TEMPERATURES IN THE UPPER
80S TO LOWER 90S. AS THE TROUGH CONTINUES TO DEEPEN HTS WILL LOWER
AND AIR TEMPS WILL CONTINUE TO COOL THROUGH THE WEEKEND. BOTH
ECMWF/GFS SUGGEST ENERGY SLIDING DOWN THE BACKSIDE OF THE UPPER
TROUGH MAY BE SUFFICIENT TO FORCING DIURNAL PRECIP SUNDAY ACROSS THE
EAST AND WILL LEAVE LOW CHC POPS IN THEN BUT FOR THE MOST PART ONCE
WE GET THROUGH THURSDAY THE WEATHER LOOKS VERY COMFORTABLE AND
MAINLY DRY WITH BELOW AVG TEMPS AND HUMIDITIES INTO NEXT WEEK. THE
UPPER TROUGH MAY LINGER THROUGH NEXT WEEK SO NEAR OR BELOW AVG TEMPS
COULD PERSIST THROUGH JULY 4TH
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1145 PM CDT WED JUN 26 2013
CONFIDENCE IN THE CONVECTIVE FORECAST FOR TOMORROW IS LOW. MODELS
HAVE SHOWN LITTLE CONTINUITY WITH THE POSSIBILITY FOR ELEVATED
NOCTURNAL STORMS. THE RAP AND HRRR IN PARTICULAR BRING ELEVATED
STORMS FROM NEB INTO THE AREA EARLY IN THE DAY. IF THIS IS THE
CASE...THERE COULD BE SCT STORMS THROUGH MUCH OF THE DAY. UNTIL
ELEVATED STORMS BECOME APPARENT...THE FORECAST REMAINS
CONSERVATIVE THINKING THE HIGHEST PROB FOR STORMS WILL BE DURING
THE PEAK HEATING OF THE DAY. LOW LEVEL CONVERGENCE ALONG A WEAK
SFC BOUNDARY AND A VERY UNSTABLE AIRMASS COULD LEAD TO EXPLOSIVE
DEVELOPMENT IF MORNING SHOWERS AND THUNDERSTORMS DO NOT FORM.
ANTICIPATE VFR CONDITIONS TO PREVAIL UNLESS CONVECTION MOVES OVER
THE TERMINALS.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM 1 PM TO 8 PM CDT THURSDAY FOR KSZ008-009-
020>023-026-034>040-054>056-058-059.
&&
$$
SHORT TERM...HENNECKE
LONG TERM...OMITT
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
420 AM CDT THU JUN 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT THU JUN 27 2013
WE FINALLY HAD A QUIET NIGHT ACROSS THE ENTIRE FORECAST AREA WITH
THE REGIONAL RADAR SHOWING WEAK SHOWERS/STORMS BOTH SOUTH AND
NORTH OF THE AREA. THERE IS A SURFACE LOW LOCATED NEAR LAKE WINNIPEG
WITH A COLD FRONT STRETCHED OUT TO THE SOUTH ACROSS WESTERN
MINNESOTA. THIS FRONT IS SLOWLY MOVING EAST WITH TIME AND IS LIKELY
PLAYING A ROLE IN GENERATING THOSE THUNDERSTORMS IN THE DULUTH AREA.
THERE IS ALSO SOME DRYING SHOWING UP IN WATER VAPOR IMAGERY IN
NORTHERN MINNESOTA WHICH HIGHLIGHTS AN AREA OF PV MOVING E-SE WITH
TIME. THOSE WIDESPREAD HIGH-BASED SHOWERS CRUISING ALONG AT 50 MPH
ARE IN A ZONE OF DECENT 850-700MB FGEN. THE MERRIMAN PROFILER IN
NORTH CENTRAL NE IS SHOWING 30 KT SOUTHWEST WINDS AT 700 MB AND THE
WOOD LAKE PROFILER IN MN SHOWS NORTHWEST WINDS AT 35 KTS AT THE SAME
LEVEL. THERE IS ALSO ABOUT A 5-7 C TEMPERATURE GRADIENT ACROSS THIS
AREA. THIS AREA OF SHOWERS TO OUR SOUTH POSES LITTLE TO NO RAIN
THREAT TO OUT AREA.
HOWEVER...THE ADVANCING COLD FRONT AND THE POSITION OF THE UPPER JET
SUGGESTS EASTERN PORTIONS OF THE FORECAST AREA COULD SEE A LITTLE
RAIN TODAY. THIS IS MAINLY AN ISSUE FOR NORTHEAST MN...NORTHWEST WI
AND AREAS TO THE SOUTHEAST OF THERE. THE BEST UPPER DIVERGENCE AND
LEFT EXIT REGION REMAIN NORTH AND EAST OF THE FORECAST AREA AND MUCH
OF THE CONVECTIVE ALLOWING MODELS DEVELOP ISOLATED-TO-SCATTERED
SHOWERS IN WEST CENTRAL WI AND THEN MOVE THE ACTIVITY EAST WITH
TIME. AS A RESULT...STILL HOLDING ON TO POPS MAINLY IN OUR WEST
CENTRAL WI COUNTIES. THE GOOD NEWS IS...THE NORTHWEST FLOW WILL
CONTINUE TO ADVECT DRIER AIR INTO MN/WI...SO THE THREAT FOR HEAVY
RAIN AND FLOODING SHOULD BE LOW. THIS IS GOOD NEWS BECAUSE MOST OF
THE AREA HAS SEEN ITS FAIR SHARE OF THE RAIN. KEAU REPORTED 1.80" OF
RAIN WITH THOSE THUNDERSTORMS YESTERDAY. THE MPX RAOB ALREADY SHOWED
A NICE DROP IN THE PWAT..FROM 1.61" AT 26.12Z TO 1.10" AT 27.00Z.
WE DROPPED THE DEWPOINTS DOWN TODAY AND KEPT THE TEMPS WARM GIVEN
THE LIKELIHOOD OF GOOD MIXING AND SUNSHINE. THE RAP/NAM BOTH
INDICATE MIXING UP TO 800 MB AND USING SOME OF OUR MIX DOWN
TOOLS..WE GET AFTERNOON DEWPOINTS IN THE 40S AND 50S. WE CERTAINLY
DIDN`T GO 40S...BUT HAVE 50S IN THERE. SO...EVEN WITH THE COOLING AT
850 MB...WE SHOULD STILL WARM NICELY TODAY. FINALLY...PATCHY DENSE
HAS FORMED THIS MORNING IN PORTIONS OF WEST CENTRAL WI...BUT THE
EXTENT SHOULD NOT BE WIDESPREAD...SO WE DO NOT ANTICIPATE AN
ADVISORY AT THIS POINT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 415 AM CDT THU JUN 27 2013
DETERMINISTIC SOLUTIONS REMAIN CONSISTENT ON DEEPENING AN UPPER
TROUGH OVER THE EASTERN CONUS THROUGH THE UPCOMING WEEKEND. A
STRONG SHORT WAVE WILL ROTATE SOUTHWARD ACROSS THE LOCAL AREA FROM
LATE FRIDAY THROUGH SATURDAY CAUSING A PERIOD OF UNSETTLED
WEATHER IN THE FORM OF SCATTERED SHOWERS AND THUNDERSTORMS.
CHANCES FOR PRECIPITATION REMAIN HIGHEST ACROSS EASTERN MN AND
WEST CENTRAL WI...WITH HIGH CHANCE TO LIKELY POPS IN PLACE. RAIN
AMOUNTS DURING THE PERIOD SHOULD RUN FROM A FEW HUNDREDTHS TO A
TENTH OF AN INCH FROM WEST TO EAST ACROSS THE MN CWA AND FROM A
TENTH TO PERHAPS A QUARTER INCH OVER WEST CENTRAL WI. THERE WILL
ALSO BE A COOL DOWN IN HIGH TEMPERATURE DURING THE WEEKEND AS
NORTHERLY FLOW OCCURS. HIGHS BOTH SATURDAY AND SUNDAY WILL BE IN
THE 70S.
SUNDAY AND MONDAY ARE DRY WITH SMALL CHANCES FOR PRECIPITATION
INCREASING ACROSS THE AREA FROM TUESDAY INTO WEDNESDAY. THIS
CHANCE OF PRECIPITATION IS TIED TO AN UPPER LOW DEVELOPING IN THE
EASTERN TROUGH AND THEN SLOWLY RETROGRADING TO THE CENTRAL PLAINS
BY LATE NEXT WEEK. AT THIS TIME...LOW CHANCE POPS ARE MAINLY CONFINED
TO WESTERN AND SOUTHERN MN. HIGHS EARLY NEXT WEEK WILL BE AT OR
SLIGHTLY BELOW SEASONAL VALUES WITH MIDDLE 70S TO AROUND 80 FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1111 CDT WED JUN 26 2013
COLD FRONT PUSHING INTO NW MN AS ISO-SCT STORMS WITH IT. BETTER
CONVERGENCE AND INSTABILITY WITH THE FRONT IS BETTER ACROSS NRN
MN...SO ANTICIPATE ANY STORMS TO REMAIN NORTH OF THE MPX TERMINALS
TONIGHT...THOUGH ALL WILL SEE AN INCREASE IN CLOUD COVER. THIS
CLOUD COVER WILL BE IMPORTANT FOR EAU CLAIRE AND FOG POTENTIAL...
AS THE LESS CLOUD COVER THEY SEE...THE MORE FOG THERE WILL BE. FOR
TOMORROW CU FIELD WILL GO FROM SCT-BKN EAST AND SKC WEST WITH NW
WINDS BECOMING GUSTY. WILL BE A SHOWER POTENTIAL IN EAU CLAIRE
DURING THE AFTERNOON...BUT SOUNDINGS FROM THE RAP/NAM SHOW LOTS OF
DRY AIR OUT THERE TO OVERCOME...SO LEFT ANY PRECIP MENTION OUT.
KMSP...HIGH CONFIDENCE IN ALL PARAMETERS THIS PERIOD. HRRR
CONTINUES TO DEVELOP SOME SHOWERS BETWEEN 9Z AND 11Z...BUT HAVING
A HARD TIME WHEN SEEING THE INSTABILITY FORECAST BY THE RAP TO
STAY IN NRN MN THROUGH THE NIGHT. WINDS WILL BE FAIRLY LIGHT
THROUGH THE NIGHT...BUT TUESDAY LOOKS TO BRING A GOOD MIXING DAY
AND SOME NW WIND GUSTS TO AROUND 25 KTS.
/OUTLOOK FOR KMSP/
FRI...VFR. CHC SHRA/TS WITH MVFR. WINDS NW AT 15G20 KTS.
SAT...VFR. CHC SHRA/TS WITH MVFR. WINDS NNW AT 10-15 KTS.
SUN...VFR. WINDS NE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...RAH
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1112 PM CDT WED JUN 26 2013
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 337 PM CDT WED JUN 26 2013
CLUSTERS OF SHOWERS AND THUNDERSTORMS HAVE ADVANCED EASTWARD INTO
WISCONSIN THIS AFTERNOON...BUT AN OUTFLOW BOUNDARY EXISTS FROM
ROUGHLY GOODHUE UP THROUGH THE TWIN CITIES METRO. WINDS HAVE VEERED
WEST OF THIS BOUNDARY AND DEW POINTS HAVE FALLEN INTO THE 50S AND
60S. ASIDE FROM THE POSSIBILITY OF A COUPLE CELLS DEVELOPING ALONG
THE OUTFLOW BOUNDARY AND THOSE ONGOING ACROSS WRN WI...NOT
ANTICIPATING MUCH ELSE THIS EVENING.
A SECONDARY FRONT WILL SAG SOUTH FROM NRN MN AND THE DAKOTAS WHICH
COULD BE A FOCUS FOR ADDITIONAL ACTIVITY OVER CENTRAL MN AND NWRN WI
OVERNIGHT. MUCAPE OF AROUND 1000 J/KG AND STRENGTHENING MID LEVEL
SHEAR WILL SUPPORT A FEW STORMS...BUT THE THREAT SHOULD BE ISOLATED
AND LIKELY NON-SEVERE.
CYCLONIC FLOW WITH A DIGGING GREAT LAKES TROUGH COULD CONTINUE THE
LOW CHANCE OF TSRA INTO THURSDAY OVER WRN WI. OTHERWISE...DRIER
NORTHWEST FLOW AND 925 MB TEMPS OF +24C WILL ALLOW FOR ANOTHER WARM
DAY IN THE MID/UPPER 80S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 337 PM CDT WED JUN 26 2013
THE OVERALL EVOLUTION OF THE UPPER LEVEL FLOW PATTERN IS THE
MAIN PROBLEM IN THE LONG TERM. MOST DETERMINISTIC MODELS DROP
SIGNIFICANT TROUGH OVER THE EASTERN CONUS DURING THE PERIOD. THE
INITIAL SURGE OF FALLING HEIGHTS AND MOISTURE MOVES INTO THE REGION
FRIDAY AND SATURDAY. THIS WILL SPREAD HIGH CHANCE POPS WEST AND
SOUTH OVER THE AREA THROUGH THIS PERIOD. INSTABILITY ASSOCIATED
WITH THIS FEATURE IS LIMITED AND WILL MENTION JUST ISOLATED
THUNDER WITH THIS ACTIVITY. WITH MORE EXTENSIVE CLOUD COVER...
TEMPERATURES SHOULD BE LIMITED TO THE 70S ON SATURDAY AS THE
TROUGH MOVES THROUGH.
FOR THE REMAINDER OF THE WEEKEND AND INTO EARLY NEXT WEEK...THE
WESTERN CONUS RIDGE ON BOTH THE GFS AND ECMWF ARE INDICATING A
GENERAL RETROGRESSION OF THE RIDGE...WITH ANOTHER STRONG WAVE
RIDING THE EASTERN EDGE OF THIS RIDGE SOUTHWARD AND CARVING A DEEPER
UPPER LOW PRESSURE AREA OVER THE CENTRAL CONUS. THIS SHOULD
PROVIDE A RATHER COOL AND POSSIBLY INCREASINGLY WETTER PERIOD AS
THE UPPER LOW SETTLES OVER THE AREA. THE CURRENT 8 TO 14 DAY
FORECAST FOR THE AREA HAS COOLER AND DRIER CONDITIONS FOR THE AREA
INTO THE EARLY PART OF NEXT MONTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1111 CDT WED JUN 26 2013
COLD FRONT PUSHING INTO NW MN AS ISO-SCT STORMS WITH IT. BETTER
CONVERGENCE AND INSTABILITY WITH THE FRONT IS BETTER ACROSS NRN
MN...SO ANTICIPATE ANY STORMS TO REMAIN NORTH OF THE MPX TERMINALS
TONIGHT...THOUGH ALL WILL SEE AN INCREASE IN CLOUD COVER. THIS
CLOUD COVER WILL BE IMPORTANT FOR EAU CLAIRE AND FOG POTENTIAL...
AS THE LESS CLOUD COVER THEY SEE...THE MORE FOG THERE WILL BE. FOR
TOMORROW CU FIELD WILL GO FROM SCT-BKN EAST AND SKC WEST WITH NW
WINDS BECOMING GUSTY. WILL BE A SHOWER POTENTIAL IN EAU CLAIRE
DURING THE AFTERNOON...BUT SOUNDINGS FROM THE RAP/NAM SHOW LOTS OF
DRY AIR OUT THERE TO OVERCOME...SO LEFT ANY PRECIP MENTION OUT.
KMSP...HIGH CONFIDENCE IN ALL PARAMETERS THIS PERIOD. HRRR
CONTINUES TO DEVELOP SOME SHOWERS BETWEEN 9Z AND 11Z...BUT HAVING
A HARD TIME WHEN SEEING THE INSTABILITY FORECAST BY THE RAP TO
STAY IN NRN MN THROUGH THE NIGHT. WINDS WILL BE FAIRLY LIGHT
THROUGH THE NIGHT...BUT TUESDAY LOOKS TO BRING A GOOD MIXING DAY
AND SOME NW WIND GUSTS TO AROUND 25 KTS.
/OUTLOOK FOR KMSP/
FRI...VFR. CHC SHRA/TS WITH MVFR. WINDS NW AT 15G20 KTS.
SAT...VFR. CHC SHRA/TS WITH MVFR. WINDS NNW AT 10-15 KTS.
SUN...VFR. WINDS NE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...BORGHOFF
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
117 PM CDT THU JUN 27 2013
.AVIATION...
18Z TAFS FOR KOMA...KLNK...KOFK.
GLANCE AT REGIONAL RADAR MOSAIC SHOWING SCT TSRA MOVING SEWD OVER
SERN NEB THIS AFTN. WITH CONVECTIVE ACTIVITY STILL HANGING ON AT
KOMA AND KLNK...WILL CONTINUE TEMPO GROUPS UNTIL ABOUT 20Z.
OTHERWISE VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS THEREAFTER THRU
THE REST OF THE FCST PD.
DEE
PREV DISCUSSION... /ISSUED 332 AM CDT THU JUN 27 2013/
DISCUSSION...
QUIET WEATHER WILL ONCE AGAIN BE INTERRUPTED BY NOCTURNAL/MORNING
CONVECTION...WITH A CONTINUED CHANCE THROUGH THE DAY. SUBJECTIVE
00Z UPPER AIR ANALYSIS INDICATES A STRENGTHENING UPPER-LEVEL HIGH
OVER THE DESERT SOUTHWEST...WITH 500MB HEIGHTS AS HIGH AS 5960M WITH
WIDESPREAD 60-90M HEIGHT RISES ACROSS AREAS WEST OF THE ROCKIES. A
SEASONALLY STRONG UPPER-LEVEL JET WAS IMPINGING ON THE PACIFIC
NORTHWEST...WITH UP TO 130KT WINDS. BROAD 850MB LOW EXTENDED ACROSS
THE ROCKIES...WITH RIDGING OVER THE CENTRAL PLAINS. A DRY POCKET
WAS NOTED UNDER THE RIDGE...WITH 850MB DEWPOINTS OF -2C TO 2C IN
EASTERN NEB/EASTERN KS/SOUTHEAST SD. HIGHER 850MB MOISTURE DID
EXTEND FROM TX INTO THE HIGH PLAINS...AND RAP ANALYSIS INDICATED A
STRENGTHENING LOW-LEVEL JET REACHING FROM THE HIGH PLAINS INTO
SOUTHERN SD...WHERE HIGHER 850MB MOISTURE WAS POOLING. AN AREA OF
SHOWERS WITH ISOLATED THUNDER HAS BLOSSOMED OVER
CENTRAL/SOUTHEASTERN SD...WITH ECHOES JUST REACHING NORTH CENTRAL TO
NORTHEAST NEB BUT NOT MUCH HITTING THE GROUND YET AT AREA OB SITES.
MAIN FORECAST CONCERNS ARE SHOWERS/THUNDERSTORMS TODAY...FOLLOWED BY
QUIET AND COOLER WEATHER. SHOWERS/ISOLATED THUNDER SHOULD CONTINUE
TO FESTER ON THE NOSE OF THE LOW-LEVEL JET...AND SHOULD BE ABLE TO
DROP INTO NORTHEAST NEB BY AROUND DAYBREAK AS MID-LEVEL RIDGE AND
DRY AIR POCKET SLIDE EASTWARD...ALLOWING MOISTENING TO LOW LEVELS.
NAM/RAP/HRRR FORECAST SOUNDINGS KEEP THE PROFILE RATHER STABLE
THROUGH THE MORNING AROUND KOFK...SO AM THINKING CHARACTER OF THE
ACTIVITY WILL REMAIN MORE IN THE SHOWERS/ISOLATED THUNDER CATEGORY
THIS MORNING...RATHER THAN TURNING INTO SOMETHING MORE STORMY.
STORMS SHOULD FESTER THROUGH THE DAY...THOUGH THEY MIGHT LOSE SOME
COVERAGE NEAR MIDDAY AS 850MB LOW/BOUNDARY REORGANIZES.
MEANWHILE...SOUTHEAST NEB SHOULD BE ABLE TO DESTABILIZE A GOOD PART
OF THE DAY AHEAD OF THE SHOWERS. AS 850MB FRONT SAGS INTO SOUTHEAST
NEB THIS AFTERNOON...WOULD EXPECT MORE OF A THUNDERSTORM MODE AS
STORMS DEVELOP IN A MORE UNSTABLE ENVIRONMENT. BULK SHEAR
ENVIRONMENT WOULD SUPPORT MORE ORGANIZED STORMS DOWN THERE...BUT
STORM DEVELOPMENT REMAINS CONDITIONAL ON WHETHER THE SOUTHERN CWA
REMAINS CLEAR LONG ENOUGH TO DESTABILIZE. IF IT DOES...COULD SEE A
FEW STORMS REACH SEVERE LIMITS IN SOUTHEAST NEB...WITH LARGE HAIL
AND DAMAGING WINDS THE MAIN THREATS. STORMS WILL CONTINUE TO SLIDE
SOUTH AND OUT OF THE AREA BY MID-EVENING.
UPPER-LEVEL FLOW WILL BECOME NORTHWESTERLY TONIGHT/FRIDAY AS INTENSE
UPPER-LEVEL RIDGE CONTINUES TO STRENGTHEN IN THE SOUTHWEST US.
NORTHWESTERLY FLOW WILL BRING COOLER TEMPERATURES BUT LARGELY DRY
WEATHER. MODELS DO INDICATE A SHORTWAVE ROTATING AROUND THE EASTERN
US TROUGH ON SATURDAY THAT WOULD BRING SHOWERS INTO IOWA...BUT IT
LOOKS LIKE THE CWA WILL REMAIN WEST OF THE PRECIP. THOUGH THE
TIMING VARIES AMONG MODEL RUNS AND SOLUTIONS...LONG-RANGE MODELS ARE
BECOMING MORE CONSISTENT IN INDICATING THAT THE EASTERN US UPPER-
LEVEL TROUGH WILL RETROGRADE INTO THE CENTRAL PLAINS AND
DEEPEN...POSSIBLY EVEN CUTTING OFF. DRY NORTHEASTERLY FLOW DOES NOT
FAVOR MUCH PRECIPITATION...AND HAVE HELD PRECIP OUT OF THE FORECAST
AT LEAST THROUGH TUESDAY. BEYOND THAT... MODEL BLENDS ARE FORCING
MUCH HIGHER CHANCES THAN I WOULD CHOOSE TO INCLUDE GIVEN THE AMOUNT
OF UNCERTAINTY AND POSSIBLITY FOR A DRY FETCH OF AIR...BUT LEFT THE
CHANCES IN FOR COLLABORATION PURPOSES. DO NOT BELIEVE THAT TUESDAY
NIGHT THROUGH THURSDAY WOULD BE A WASHOUT...DESPITE PROLONGED PERIOD
OF PRECIP CHANCES...BUT COULD SEE PERIODS OF SHOWERS IF THE UPPER
LOW DOES INDEED DEEPEN AND RETROGRADE OVER THE CENTRAL PLAINS.
EITHER WAY...PATTERN WILL REMAIN COOLER THAN AVERAGE THROUGH NEXT
WORK WEEK AND ENTERING THE HOLIDAY WEEKEND.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
605 AM CDT THU JUN 27 2013
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
SCATTERED TSTMS SHOULD AFFECT THE TAF SITES...WITH TEMPORARY MVFR
CONDITIONS POSSIBLE. KEPT MENTION OF TSRA AT KOFK UNTIL MID
DAY...BUT INTO MID AFTN AT KOMA AND KLNK. SOME STORMS MAY PRODUCE
GUSTY WINDS...SO DID INCLUDE MENTION OF THAT. LATER TODAY AND INTO
TONIGHT...EXPECT VFR CONDITIONS AND FAIRLY LIGHT WINDS. MODELS
SHOW SOME MOISTURE AROUND 8000 FEET LATE TONIGHT...BUT DID NOT
ADD ANOTHER GROUP FOR THAT AT THIS POINT.
MILLER
&&
.PREV DISCUSSION... /ISSUED 332 AM CDT THU JUN 27 2013/
DISCUSSION...
QUIET WEATHER WILL ONCE AGAIN BE INTERRUPTED BY NOCTURNAL/MORNING
CONVECTION...WITH A CONTINUED CHANCE THROUGH THE DAY. SUBJECTIVE
00Z UPPER AIR ANALYSIS INDICATES A STRENGTHENING UPPER-LEVEL HIGH
OVER THE DESERT SOUTHWEST...WITH 500MB HEIGHTS AS HIGH AS 5960M WITH
WIDESPREAD 60-90M HEIGHT RISES ACROSS AREAS WEST OF THE ROCKIES. A
SEASONALLY STRONG UPPER-LEVEL JET WAS IMPINGING ON THE PACIFIC
NORTHWEST...WITH UP TO 130KT WINDS. BROAD 850MB LOW EXTENDED ACROSS
THE ROCKIES...WITH RIDGING OVER THE CENTRAL PLAINS. A DRY POCKET
WAS NOTED UNDER THE RIDGE...WITH 850MB DEWPOINTS OF -2C TO 2C IN
EASTERN NEB/EASTERN KS/SOUTHEAST SD. HIGHER 850MB MOISTURE DID
EXTEND FROM TX INTO THE HIGH PLAINS...AND RAP ANALYSIS INDICATED A
STRENGTHENING LOW-LEVEL JET REACHING FROM THE HIGH PLAINS INTO
SOUTHERN SD...WHERE HIGHER 850MB MOISTURE WAS POOLING. AN AREA OF
SHOWERS WITH ISOLATED THUNDER HAS BLOSSOMED OVER
CENTRAL/SOUTHEASTERN SD...WITH ECHOES JUST REACHING NORTH CENTRAL TO
NORTHEAST NEB BUT NOT MUCH HITTING THE GROUND YET AT AREA OB SITES.
MAIN FORECAST CONCERNS ARE SHOWERS/THUNDERSTORMS TODAY...FOLLOWED BY
QUIET AND COOLER WEATHER. SHOWERS/ISOLATED THUNDER SHOULD CONTINUE
TO FESTER ON THE NOSE OF THE LOW-LEVEL JET...AND SHOULD BE ABLE TO
DROP INTO NORTHEAST NEB BY AROUND DAYBREAK AS MID-LEVEL RIDGE AND
DRY AIR POCKET SLIDE EASTWARD...ALLOWING MOISTENING TO LOW LEVELS.
NAM/RAP/HRRR FORECAST SOUNDINGS KEEP THE PROFILE RATHER STABLE
THROUGH THE MORNING AROUND KOFK...SO AM THINKING CHARACTER OF THE
ACTIVITY WILL REMAIN MORE IN THE SHOWERS/ISOLATED THUNDER CATEGORY
THIS MORNING...RATHER THAN TURNING INTO SOMETHING MORE STORMY.
STORMS SHOULD FESTER THROUGH THE DAY...THOUGH THEY MIGHT LOSE SOME
COVERAGE NEAR MIDDAY AS 850MB LOW/BOUNDARY REORGANIZES.
MEANWHILE...SOUTHEAST NEB SHOULD BE ABLE TO DESTABILIZE A GOOD PART
OF THE DAY AHEAD OF THE SHOWERS. AS 850MB FRONT SAGS INTO SOUTHEAST
NEB THIS AFTERNOON...WOULD EXPECT MORE OF A THUNDERSTORM MODE AS
STORMS DEVELOP IN A MORE UNSTABLE ENVIRONMENT. BULK SHEAR
ENVIRONMENT WOULD SUPPORT MORE ORGANIZED STORMS DOWN THERE...BUT
STORM DEVELOPMENT REMAINS CONDITIONAL ON WHETHER THE SOUTHERN CWA
REMAINS CLEAR LONG ENOUGH TO DESTABILIZE. IF IT DOES...COULD SEE A
FEW STORMS REACH SEVERE LIMITS IN SOUTHEAST NEB...WITH LARGE HAIL
AND DAMAGING WINDS THE MAIN THREATS. STORMS WILL CONTINUE TO SLIDE
SOUTH AND OUT OF THE AREA BY MID-EVENING.
UPPER-LEVEL FLOW WILL BECOME NORTHWESTERLY TONIGHT/FRIDAY AS INTENSE
UPPER-LEVEL RIDGE CONTINUES TO STRENGTHEN IN THE SOUTHWEST US.
NORTHWESTERLY FLOW WILL BRING COOLER TEMPERATURES BUT LARGELY DRY
WEATHER. MODELS DO INDICATE A SHORTWAVE ROTATING AROUND THE EASTERN
US TROUGH ON SATURDAY THAT WOULD BRING SHOWERS INTO IOWA...BUT IT
LOOKS LIKE THE CWA WILL REMAIN WEST OF THE PRECIP. THOUGH THE
TIMING VARIES AMONG MODEL RUNS AND SOLUTIONS...LONG-RANGE MODELS ARE
BECOMING MORE CONSISTENT IN INDICATING THAT THE EASTERN US UPPER-
LEVEL TROUGH WILL RETROGRADE INTO THE CENTRAL PLAINS AND
DEEPEN...POSSIBLY EVEN CUTTING OFF. DRY NORTHEASTERLY FLOW DOES NOT
FAVOR MUCH PRECIPITATION...AND HAVE HELD PRECIP OUT OF THE FORECAST
AT LEAST THROUGH TUESDAY. BEYOND THAT... MODEL BLENDS ARE FORCING
MUCH HIGHER CHANCES THAN I WOULD CHOOSE TO INCLUDE GIVEN THE AMOUNT
OF UNCERTAINTY AND POSSIBLITY FOR A DRY FETCH OF AIR...BUT LEFT THE
CHANCES IN FOR COLLABORATION PURPOSES. DO NOT BELIEVE THAT TUESDAY
NIGHT THROUGH THURSDAY WOULD BE A WASHOUT...DESPITE PROLONGED PERIOD
OF PRECIP CHANCES...BUT COULD SEE PERIODS OF SHOWERS IF THE UPPER
LOW DOES INDEED DEEPEN AND RETROGRADE OVER THE CENTRAL PLAINS.
EITHER WAY...PATTERN WILL REMAIN COOLER THAN AVERAGE THROUGH NEXT
WORK WEEK AND ENTERING THE HOLIDAY WEEKEND.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
332 AM CDT THU JUN 27 2013
.DISCUSSION...
QUIET WEATHER WILL ONCE AGAIN BE INTERRUPTED BY NOCTURNAL/MORNING
CONVECTION...WITH A CONTINUED CHANCE THROUGH THE DAY. SUBJECTIVE
00Z UPPER AIR ANALYSIS INDICATES A STRENGTHENING UPPER-LEVEL HIGH
OVER THE DESERT SOUTHWEST...WITH 500MB HEIGHTS AS HIGH AS 5960M WITH
WIDESPREAD 60-90M HEIGHT RISES ACROSS AREAS WEST OF THE ROCKIES. A
SEASONALLY STRONG UPPER-LEVEL JET WAS IMPINGING ON THE PACIFIC
NORTHWEST...WITH UP TO 130KT WINDS. BROAD 850MB LOW EXTENDED ACROSS
THE ROCKIES...WITH RIDGING OVER THE CENTRAL PLAINS. A DRY POCKET
WAS NOTED UNDER THE RIDGE...WITH 850MB DEWPOINTS OF -2C TO 2C IN
EASTERN NEB/EASTERN KS/SOUTHEAST SD. HIGHER 850MB MOISTURE DID
EXTEND FROM TX INTO THE HIGH PLAINS...AND RAP ANALYSIS INDICATED A
STRENGTHENING LOW-LEVEL JET REACHING FROM THE HIGH PLAINS INTO
SOUTHERN SD...WHERE HIGHER 850MB MOISTURE WAS POOLING. AN AREA OF
SHOWERS WITH ISOLATED THUNDER HAS BLOSSOMED OVER
CENTRAL/SOUTHEASTERN SD...WITH ECHOES JUST REACHING NORTH CENTRAL TO
NORTHEAST NEB BUT NOT MUCH HITTING THE GROUND YET AT AREA OB SITES.
MAIN FORECAST CONCERNS ARE SHOWERS/THUNDERSTORMS TODAY...FOLLOWED BY
QUIET AND COOLER WEATHER. SHOWERS/ISOLATED THUNDER SHOULD CONTINUE
TO FESTER ON THE NOSE OF THE LOW-LEVEL JET...AND SHOULD BE ABLE TO
DROP INTO NORTHEAST NEB BY AROUND DAYBREAK AS MID-LEVEL RIDGE AND
DRY AIR POCKET SLIDE EASTWARD...ALLOWING MOISTENING TO LOW LEVELS.
NAM/RAP/HRRR FORECAST SOUNDINGS KEEP THE PROFILE RATHER STABLE
THROUGH THE MORNING AROUND KOFK...SO AM THINKING CHARACTER OF THE
ACTIVITY WILL REMAIN MORE IN THE SHOWERS/ISOLATED THUNDER CATEGORY
THIS MORNING...RATHER THAN TURNING INTO SOMETHING MORE STORMY.
STORMS SHOULD FESTER THROUGH THE DAY...THOUGH THEY MIGHT LOSE SOME
COVERAGE NEAR MIDDAY AS 850MB LOW/BOUNDARY REORGANIZES.
MEANWHILE...SOUTHEAST NEB SHOULD BE ABLE TO DESTABILIZE A GOOD PART
OF THE DAY AHEAD OF THE SHOWERS. AS 850MB FRONT SAGS INTO SOUTHEAST
NEB THIS AFTERNOON...WOULD EXPECT MORE OF A THUNDERSTORM MODE AS
STORMS DEVELOP IN A MORE UNSTABLE ENVIRONMENT. BULK SHEAR
ENVIRONMENT WOULD SUPPORT MORE ORGANIZED STORMS DOWN THERE...BUT
STORM DEVELOPMENT REMAINS CONDITIONAL ON WHETHER THE SOUTHERN CWA
REMAINS CLEAR LONG ENOUGH TO DESTABILIZE. IF IT DOES...COULD SEE A
FEW STORMS REACH SEVERE LIMITS IN SOUTHEAST NEB...WITH LARGE HAIL
AND DAMAGING WINDS THE MAIN THREATS. STORMS WILL CONTINUE TO SLIDE
SOUTH AND OUT OF THE AREA BY MID-EVENING.
UPPER-LEVEL FLOW WILL BECOME NORTHWESTERLY TONIGHT/FRIDAY AS INTENSE
UPPER-LEVEL RIDGE CONTINUES TO STRENGTHEN IN THE SOUTHWEST US.
NORTHWESTERLY FLOW WILL BRING COOLER TEMPERATURES BUT LARGELY DRY
WEATHER. MODELS DO INDICATE A SHORTWAVE ROTATING AROUND THE EASTERN
US TROUGH ON SATURDAY THAT WOULD BRING SHOWERS INTO IOWA...BUT IT
LOOKS LIKE THE CWA WILL REMAIN WEST OF THE PRECIP. THOUGH THE
TIMING VARIES AMONG MODEL RUNS AND SOLUTIONS...LONG-RANGE MODELS ARE
BECOMING MORE CONSISTENT IN INDICATING THAT THE EASTERN US UPPER-
LEVEL TROUGH WILL RETROGRADE INTO THE CENTRAL PLAINS AND
DEEPEN...POSSIBLY EVEN CUTTING OFF. DRY NORTHEASTERLY FLOW DOES NOT
FAVOR MUCH PRECIPITATION...AND HAVE HELD PRECIP OUT OF THE FORECAST
AT LEAST THROUGH TUESDAY. BEYOND THAT... MODEL BLENDS ARE FORCING
MUCH HIGHER CHANCES THAN I WOULD CHOOSE TO INCLUDE GIVEN THE AMOUNT
OF UNCERTAINTY AND POSSIBLITY FOR A DRY FETCH OF AIR...BUT LEFT THE
CHANCES IN FOR COLLABORATION PURPOSES. DO NOT BELIEVE THAT TUESDAY
NIGHT THROUGH THURSDAY WOULD BE A WASHOUT...DESPITE PROLONGED PERIOD
OF PRECIP CHANCES...BUT COULD SEE PERIODS OF SHOWERS IF THE UPPER
LOW DOES INDEED DEEPEN AND RETROGRADE OVER THE CENTRAL PLAINS.
EITHER WAY...PATTERN WILL REMAIN COOLER THAN AVERAGE THROUGH NEXT
WORK WEEK AND ENTERING THE HOLIDAY WEEKEND.
MAYES
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
EXPECTING THE FIRST FEW HOURS OF THE TAF CYCLE TO BE FAIRLY QUIET
WITH LIGHT AND VARIABLE SFC WINDS AND VFR CONDITIONS.
THUNDERSTORMS ARE EXPECTED TO DEVELOP TO THE NORTHWEST OF THE TAF
SITES AFTER 09Z AND ROLL SOUTHEAST THROUGHOUT THE MORNING HOURS.
HAVE INCLUDED TEMPO GROUPS FOR ALL 3 SITES. KLNK MAY SEE THE
STORMS LINGER THE LONGEST OVER THE MORNING AND POSSIBLY CONTINUE
INTO THE AFTERNOON HOURS.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
213 PM EDT THU JUN 27 2013
.SYNOPSIS...
A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY
AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME
SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND
WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WATER VAPOR IMAGERY DISPLAYS A SHORTWAVE TROUGH NEAR NE OH THIS
MORNING. JUST TO THE EAST OF THE CUSP...WHICH IS FOUND ON THE
WESTERN SIDE OF THE UPPER LEVEL CIRCULATION IS FOUND AT THE SURFACE
AN AREA OF LOW PRESSURE...WHICH CAN ALSO BE SEEN IN RADAR LOOPS AND
SURFACE ANALYSIS AS A WEAK AREA OF LOW PRESSURE. LATEST IR AND
VISIBLE SATELLITE IMAGERY SHOWS COOLING CLOUD TOPS ASSOCIATED WITH
THE WARM CONVEYOR BELT WHICH WILL CONTINUE TO STREAM MOISTURE
NORTHWARD AHEAD OF THE UPPER LEVEL SHORTWAVE. THIS WILL FOCUS THE
GREATEST MOISTURE...AND COUPLED WITH THE BEST ISENTROPIC LIFT AND
SYNOPTIC LIFT WILL FOCUS THE HEAVIEST RAIN THROUGH THE DAYTIME
ACROSS THE SOUTHERN TIER. DAYTIME HEATING MAY TRIGGER SHOWERS AND AN
ISOLATED THUNDERSTORM AHEAD OF THE MAIN SLUG OF RAINFALL WHICH WILL
ONLY SLOWLY WORK ITS WAY NORTHWARD TODAY.
THE 00Z/06Z RUNS OF THE NAM...AND TO A LESSER EXTENT THE 00Z
GFS/UKMET/EURO KEEP THE MAJORITY OF THE PRECIPITATION IN FAR
SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE DAY. MEANWHILE THE RGEM
AND SEVERAL HRRR RUNS ARE FURTHER NORTH...PERHAPS KEYING ON A SUBTLE
SURFACE CONVERGENCE BOUNDARY SOUTH OF LAKE ONTARIO. RECALLING AN
EVENT A WEEK AGO WHERE THE OUTLYING RGEM DID HAVE THE BEST HANDLE ON
A SIMILAR SYSTEM...WILL CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE
A BLEND OF BOTH CAMPS OF GUIDANCE. EARLY MORNING RADAR TREND TEND TO
SUPPORT THE HRRR/RGEM SOLUTIONS WHICH BRING AN AREA OF RAIN ACROSS
WESTERN NEW YORK TODAY.
FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH
STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF.
RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY
TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE
ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE
FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL
BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS
(00Z NAM/RGEM/GFS/EURO AND 03Z SREF) IS FAIRLY CONSISTENT IN PUTTING
THE STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES
REGIONS FOR TONIGHT. THIS SAID...06Z RUNS OF THE NAM/GFS HAVE
SHIFTED A BIT SOUTH AND EAST...BUT GIVEN THEY HAVE NOT BEEN
VERIFYING WELL UP TO THIS POINT...WILL NOT GIVE THESE SOLUTIONS
TOO MUCH WEIGHT.
A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE
POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL
GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN
SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING
UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR
SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE
FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST
RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE
BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT
AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON
THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING
FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON DUE TO
EXTREMELY SLOW STORM MOTION. WHILE QPFS ARE LESS ELSEWHERE...THERE
STILL IS A POTENTIAL...ESPECIALLY CONSIDERING RAINFALL AMOUNTS IN
EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL BUFFALO CREEKS TO
BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES UP...AND BASED ON
THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP THE TIMING FOR
THE EASTERN LAKE ONTARIO SECTION OF THE WATCH.
OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE
TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH
ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE
FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY
CONDITIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD
AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE
LOW LIFT VERY SLOWLY TO THE NORTH.
ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE
IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH
TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED
CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD
SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE.
THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL.
ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY)
WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED
BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET
STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW
ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY
RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE
NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL
FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW.
IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE
QUARTERS OF AN INCH OF RAIN ON FRIDAY.
AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT
THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL
FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN
NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND
VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS
AREA.
REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER
MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT
EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM
CONVECTION.
SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN
PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A
FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE
POSSIBILITY OF LIMITED SUNSHINE.
EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS
PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT
OF THE 60S DUE TO THE ANTICIPATED RAINFALL.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE
EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS
TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING
MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN
RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH
RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE
TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT
LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND
NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW
NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE
UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF
THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO
OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST
PERIOD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT 18Z THE MAIN BAND OF HEAVY RAIN SHOWERS WAS LARGELY CONFINED TO
THE SOUTHERN TIER...INCLUDING THE KJHW TERMINAL. THIS BAND OF RAIN
WILL CONTINUE TO WEAKEN...THOUGH LOW CIGS MAY LINGER THROUGH THE
AFTERNOON. ELSEWHERE...AND MAINLY SOUTH OF LAKE ONTARIO SHOWERS AND
ISOLATED THUNDERSTORMS WILL CONTINUE TO BLOSSOM THROUGH THE
AFTERNOON HEAT.
THE MAIN SFC LOW WILL TRACK ACROSS PA AND INTO EASTERN NEW YORK
STATE THIS AFTERNOON. THIS WILL CARRY THE HEAVY RAIN EASTWARD SUCH
THAT IT WILL CLIP JUST THE EASTERN PORTIONS OF THE AREA...INCLUDING
THE KART TERMINAL THROUGH THE OVERNIGHT. ELSEWHERE A LULL IN THE
SHOWERS AND THUNDERSTORMS THIS EVENING BEFORE ADDITIONAL
SHOWERS...AND POSSIBLE THUNDER ADVANCE TOWARDS WNY AHEAD OF THE NEXT
SHORTWAVE. CIGS AND VSBYS MAY LOWER TO IFR/MVFR IN ANY SHOWER AND
THUNDERSTORM ACTIVITY.
WITH THE WINDS SHIFTING TO A NORTHERLY FLOW AS THE SURFACE LOW
TRACKS EASTWARD CIGS OVERNIGHT AND TOMORROW MORNING WILL LIKELY DROP
TO LOW END MVFR OR IFR.
OUTLOOK...
FRIDAY AFTERNOON...MVFR IN SHOWERS.
SATURDAY THROUGH TUESDAY...MAINLY VFR WITH A CHANCE OF MAINLY
AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR.
&&
.MARINE...
LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY
WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA
CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL
DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLOOD WATCH THROUGH FRIDAY EVENING FOR NYZ006>008.
FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ001>005-010>014-
019>021-085.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/THOMAS
SHORT TERM...TJP
LONG TERM...WOOD
AVIATION...THOMAS
MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1257 PM EDT THU JUN 27 2013
.SYNOPSIS...
THIS AFTERNOON THROUGH THE OVERNIGHT PERIOD, A STRONG SUMMERTIME
SYSTEM WILL IMPACT THE REGION, WITH SHOWERS AND THUNDERSTORMS
PRODUCING LOCALLY HEAVY RAINFALL. AN UPPER LEVEL TROF WILL REMAIN
OVER THE REGION THROUGH THIS WEEKEND BRINGING MORE SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...
GRIDS FINALLY UPDATED TO REFLECT CURRENT TRENDS AND THINKING
ALONG WITH SUPPORTIVE FLASH FLOOD WATCH (FFA) AND HWO PRODUCTS.
LATEST 13Z SUBJECTIVE SFC ANALYSIS PLACES PRIMARY SFC LOW ACROSS
WESTERN PA...WITH CORRESPONDING STATIONARY FRONT EXTENDING EAST
THROUGH CENTRAL PA...NORTHERN NEW JERSEY...AND EVENTUALLY THE
LONG ISLAND SOUND. TO THE SOUTH OF THIS BOUNDARY...DEW POINTS
LARGELY RESIDE IN THE LOWER 70S...WITH AREAS NORTH OF THE FRONT
SHOWING CONTINUED NORTHEAST WINDS WITH DEW POINTS MAINLY IN THE
MIDDLE TO UPPER 60S. AS WE PROGRESS INTO THE AFTERNOON HRS...MAIN
CONCERNS REMAIN FOCUSED ON TWO AREAS WITH THE FIRST BEING POSSIBLE
SEVERE STORMS FOR AREAS THAT DO IN FACT BREAK INTO THE WARM
SECTOR PRIOR TO HEAVY RAINS MOVING IN...AND THE SECOND OBVIOUSLY
CENTERED ON THE DEVELOPING FLASH FLOOD THREAT.
FIRST FOR THE SEVERE THREAT...LATEST VIS SATELLITE IMAGERY SHOWING
JUST HIGH CIRRUS ACROSS THE EASTERN ZONES THIS HR WITH PLENTY OF
FILTERED SUN MAKING ITS WAY TO THE SURFACE. MAIN CLOUD SHIELD
ASSOCIATED WITH HEAVY RAINS STILL TO THE WEST THIS HR BUT MAKING
STEADY PROGRESS EAST. LATEST RUC ANALYSIS SHOWS A SLOW MOVING
SHORTWAVE WORKING THROUGH THE AREA CURRENTLY...WITH THIS FEATURE
EXPECTED TO EXIT OFF TO OUR EAST WITHIN THE NEXT FEW HRS. FCST
925 AND 850 MB WINDS SHOW VERY FAIRLY WEAK SOUTHEASTERLY FLOW
THROUGH THIS AFTERNOON LENDING CONCERN THAT AFOREMENTIONED FRONTAL
BOUNDARY WILL HAVE A DIFFICULT TIME ADVANCING NORTH THROUGH THE
REMAINDER OF THE DAY. MAIN ISSUES PREVENTING WIDESPREAD DEEP MOIST
CONVECTION STEMS FROM OVERALL LACK OF INSTABILITY BASED ON
BETTER DEW POINTS/HEATING REMAINING TO THE SOUTH. BIG WILD CARD
WILL BE WHETHER THIS FRONT IS ABLE TO MOVE NORTH INTO THE SOUTHERN
CATSKILLS/LWR WYOMING VLY/AND POCONOS LATER TODAY. THAT
SAID...BEST POTENTIAL SEEMS TO BE FOCUSED OVER THESE AREAS WHERE
ISOLATED STRONG WILDS APPEAR TO BE THE BIGGEST THREAT.
MOVING ON...FOCUS WILL BECOME MORE HYDRO FOCUSED AS STRONG UPPER
WAVE TAPPING AN INCREASING MOIST AND TROPICAL AIRSTREAM MIGRATES
EAST WITH TIME. STRONG FORCING ARRIVING FROM THE MAIN MID-LEVEL
VORTICITY MAXIMUM WILL BE STRONGLY SUPPORTED BY A NOW DEVELOPING
COUPLED JET CIRCULATION WHICH WILL TARGET MUCH OF OUR FCST REGION
LATER TODAY INTO TONIGHT. AS THIS OCCURS...LOW-LEVEL JET WINDS ARE
PROGGED TO INCREASE TO NEAR 40 KTS AS THE THERMALLY DIRECT COUPLED
JET CIRCULATION MATURES WITH TIME. AS THIS OCCURS...AN AIRMASS
WITH TROPICAL ORIGINS /SEE LATEST BLENDED TPW SATELLITE IMAGERY/
WITH PWAT VALUES NOW APPROACHING 2" JUST SOUTH OF OUR FCST REGION
WILL ADVANCE NORTH AND OVER THE FRONTAL BOUNDARY JUST TO OUR
SOUTH /I.E. MADDOX FRONTAL TYPE FF EVENT?/. FOR WHAT ITS
WORTH...WFO CTP ALREADY ISSUING ACTIVE FLOOD STATEMENTS AND MAKING
REFERENCE TO 3"/HR RAINFALL RATES. OBVIOUSLY AS THIS AIRMASS WORKS
OVER THE AREA COMBINED WITH STRONG SYNOPTIC SUPPORT ALOFT...FLASH
FLOODING DEFINITELY A LIKELIHOOD LATER TODAY/TONIGHT. AS A
RESULT...NO CHANGES TO THE CURRENT FLASH FLOOD PRODUCT ANTICIPATED
ON THE DAY SHIFT.
620 AM UPDATE...AREAS OF DENSE FOG CURRENTLY EXTENDS ACROSS
THE TWIN TIERS AS CI OVERSPREADS THE REGION. HIGH CLOUDS MAY
PREVENT SOME MIXING INITIALLY EARLY THIS MORNING THEREFORE KEPT
FOG IN THE FORECAST UNTIL MID MORNING. NO OTHER CHANGES.
AT 445 AM...SKIES WERE MAINLY CLEAR OVER THE REGION WITH DENSE
VALLEY FOG ACROSS THE TWIN TIERS.
MODELS ARE IN MUCH BETTER AGREEMENT THIS MORNING WITH SYSTEM
LIFTING NORTHEAST FROM THE OHIO VALLEY. UPPER LEVEL TROF WILL
ADVANCE EASTWARD TOWARD THE REGION TODAY BRINGING WIDESPREAD
SHOWERS AND EMBEDDED THUNDERSTORMS INTO THE AREA FROM SOUTHWEST TO
NORTHEAST FROM EARLY THIS AFTERNOON THROUGH THIS EVENING.
SYSTEM WILL HAVE THE CAPACITY FOR LOCALIZED HEAVY RAINFALL AS
AIRMASS IS VERY MOIST WITH PWATS OF 1.50-2.00 INCHES. JET DYNAMICS
ARE ALSO VERY IMPRESSIVE WITH DOUBLE JET STRUCTURE RESULTING IN
STRONG UPPER LEVEL DIVERGENCE THIS EVENING THROUGH THE OVERNIGHT
PERIOD. MODELS ARE IN MUCH BETTER AGREEMENT WITH SFC LOW TRACK
TAKING FEATURE FROM CENTRAL PA NORTHEAST INTO THE NORTHERN TIER
OF PA THEN INTO THE WESTERN CATSKILLS. WITH THIS TRACK FEEL THE
MOST LIKELY AREA FOR HEAVY RAINFALL WILL BE ACROSS NE PA INTO THE
WESTERN CATSKILLS WHERE LOW LEVEL JET AND BEST MOISTURE ADVECTION
WILL RESIDE. A GENERAL 1 TO 2 INCHES OF RAINFALL IS LIKELY OVER
THE REGION WITH LOCALIZED AMOUNTS AROUND 3 INCHES OR GREATER POSSIBLE.
SEVERE WEATHER LATER TODAY AND INTO THIS EVENING IS STILL A
POSSIBILITY BUT WEAK LAPSE RATES AND MID LEVEL WIND FIELDS IS A
LIMITING FACTOR. SHEAR WILL INCREASE LATER TODAY THROUGH THIS
EVENING AS UPPER LEVEL TROF APPROACHES AND IF ENOUGH DESTABILIZATION
OCCURS A FEW CELLS COULD PRODUCE DAMAGING WINDS. THE BEST AREA FOR
THIS ACTIVITY WOULD BE THE EASTERN CWA WHERE CAPE VALUES MAY BE
MORE SIGNIFICANT.
WILL CONTINUE WITH FLASH FLOOD WATCH FOR THE ENTIRE AREA THIS
AFTERNOON THROUGH TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
UPPER LEVEL TROF WILL DEEPEN OVER THE REGION DURING THIS PERIOD
WITH SFC LOW PRES INITIALLY LIFTING NORTHEAST INTO SOUTHERN
QUEBEC THEN RETROGRADING BACK UNDER THE UPPER LEVEL FEATURE.
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE
PERIOD WITH THE MOST WIDESPREAD COVERAGE EXPECTED DURING THE
DAYLIGHT HOURS ENHANCED BY DIURNAL INSTABILITY.
MAX TEMPS BOTH FRIDAY AND SATURDAY WILL GENERALLY RANGE IN THE
70S WITH VALLEY AREAS IN NE PA AROUND 80.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
1 PM THU DISC... GLOBAL MODEL/WPC CONSENSUS CONTS TO SUGGEST QUITE AN
AMPLIFIED PATN FOR THIS TIME OF YEAR...WITH A SIG WRN
CONUS/CANADIAN RIDGE...AND ERN CONUS TROUGH. THIS LIKELY SPELLS A
WET PATN FOR NY/PA...WITH A SUSTAINED DEEP SRLY FLOW...AND LIKELY
S/WV IMPULSES RIDING NWD/NEWD UP THE FRONT SIDE OF THE
AFOREMENTIONED TROUGH AXIS. THUS...SCTD-NUMEROUS/LIKELY POPS WILL
BE RETAINED FOR MUCH OF THE PD.
ALTHOUGH MUGGY CONDS ARE FORESEEN...PERSISTENT PCPN SHOULD KEEP
HIGH TEMPS IN THE 70S-LWR 80S EACH DAY.
PREV DISC... 400 AM EDT UPDATE...
PREVIOUS FORECAST IS IN GOOD SHAPE. MINOR CHANGES TO THE TEMPS WERE
MADE. KEPT POPS THE SAME.
EARLIER DISC... 420 PM WED UPDATE... CONCERNS CONTINUE TO RISE
THIS AFTERNOON FOR A POTENTIAL SIGNIFICANT HYDROLOGIC EVENT FOR
PORTIONS OF THE EAST COAST LATE THIS WEEKEND INTO MIDWEEK AS A
STAGNANT NORTH-SOUTH MERIDIONAL FLOW PATTERN TRANSPORTS LARGE
AMOUNTS OF TROPICAL MOISTURE NORTH INTO THE MIDDLE ATLANTIC AND
NEW ENGLAND REGIONS. LATEST 12Z GEFS STANDARDIZED ANOMALY GRAPHICS
CONTINUE TO ADVERTISE AN INCREASINGLY BLOCKY PATTERN WITH VERY
AMPLIFIED HIGH PRESSURE DEVELOPING ACROSS THE INTERMOUNTAIN WEST
WITH ADDITIONAL DOWNSTREAM RIDGING EXPECTED TO STRENGTHEN OVER
TIME ACROSS THE NORTHERN ATLANTIC. AS HAS BEEN ADVERTISED OVER THE
PAST FEW DAYS...VERY DEEP TROUGHING WILL DEVELOP WEST OF OUR
FORECAST REGION WITH THE ASSOCIATED TROUGH AXIS EXPECTED TO EXTEND
WELL SOUTH INTO THE GULF OF MEXICO BY EARLY WEEK. AS AN INDICATION
OF HOW ANOMALOUS THE DEVELOPING PATTERN IS EXPECTED TO BE...LATEST
WPC EXTENDED DISCUSSIONS NOW SPEAKING OF POSSIBLE ALL-TIME RECORD
HIGHS ACROSS PORTIONS OF THE DESERT SOUTHWEST. MEANWHILE FOR AREAS
CLOSER TO US...PWAT ANOMALY GRAPHICS ARRIVING THIS AFTERNOON
SHOWING STRONG TROPICAL MOISTURE CONNECTIONS TO THE SOUTH
ATLANTIC/CARIBBEAN...WITH AN ADDITIONAL COMPONENT EXPECTED TO
ARRIVE FROM THE EAST-CENTRAL PACIFIC. THE CONVERGENCE OF BOTH LOW
/MID-LEVEL AIR STREAMS WILL FUNNEL ITS WAY NORTH WITH TIME
RESULTING IN WIDESPREAD RAIN/POTENTIALLY HEAVY RAIN DEVELOPMENT. A
LITTLE TOO EARLY TO DIVE INTO EXACT DETAILS THIS FAR OUT BUT
CONFIDENCE CONTINUES TO INCREASE THAT FLOODING RAINS ARE POSSIBLE
SOMEWHERE ALONG THE ATLANTIC SEABOARD BEGINNING THIS WEEKEND AND
LASTING THROUGH AT LEAST MIDWEEK. IN ANY EVENT...HAVE CONTINUED
LIKELY POPS THROUGH THE PERIOD AND WILL CONTINUE TO ADVERTISE
HEAVY RAIN POTENTIAL IN THE HWO PRODUCT.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z UPDATE... PRIMARILY VFR CONDS THROUGH MID TO LATE AFTN...WILL
DETERIORATE INTO THE EARLY EVE PD...AS A LARGE AREA OF RAIN (OCNLY
HVY) TRANSLATES NEWD INTO CNY/NE PA. THERE MAY BE EMBEDDED
TSRA...BUT DUE TO UNCERTAIN COVERAGE/DVLPMT...WILL OPT TO LEAVE
OUT OF THE FCST FOR THE TIME BEING. ATTM...IT LOOKS LIKE THE MOST
PERSISTENT HVYR PCPN WILL BE AT KAVP/KBGM...AND PERHAPS KRME.
WIDESPREAD LWR CLDS/FOG LATE AT NGT INTO EARLY FRI...WILL GRDLY
IMPROVE BACK TO VFR TWDS LATE MRNG/MIDDAY.
OUTLOOK...SAT THROUGH TUE...
SAT THROUGH TUE... OCNL RESTRICTIONS ARE LIKELY EACH DAY...WITH
SHRA/TSRA IN THE VICINITY. THE MOST PERSISTENT RESTRICTIONS MAY
COME BY MON/TUE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR PAZ038>040-043-
044-047-048-072.
NY...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ009-015>018-
022>025-036-037-044>046-055>057-062.
&&
$$
SYNOPSIS...RRM
NEAR TERM...CMG/RRM
SHORT TERM...RRM
LONG TERM...CMG/KAH/MLJ
AVIATION...KAH/MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1101 AM EDT THU JUN 27 2013
.SYNOPSIS...
THIS AFTERNOON THROUGH THE OVERNIGHT PERIOD, A STRONG SUMMERTIME
SYSTEM WILL IMPACT THE REGION, WITH SHOWERS AND THUNDERSTORMS
PRODUCING LOCALLY HEAVY RAINFALL. AN UPPER LEVEL TROF WILL REMAIN
OVER THE REGION THROUGH THIS WEEKEND BRINGING MORE SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...
GRIDS FINALLY UPDATED TO REFLECT CURRENT TRENDS AND THINKING
ALONG WITH SUPPORTIVE FLASH FLOOD WATCH (FFA) AND HWO PRODUCTS.
LATEST 13Z SUBJECTIVE SFC ANALYSIS PLACES PRIMARY SFC LOW ACROSS
WESTERN PA...WITH CORRESPONDING STATIONARY FRONT EXTENDING EAST
THROUGH CENTRAL PA...NORTHERN NEW JERSEY...AND EVENTUALLY THE
LONG ISLAND SOUND. TO THE SOUTH OF THIS BOUNDARY...DEWPOINTS
LARGELY RESIDE IN THE LOWER 70S...WITH AREAS NORTH OF THE FRONT
SHOWING CONTINUED NORTHEAST WINDS WITH DEWPOINTS MAINLY IN THE
MIDDLE TO UPPER 60S. AS WE PROGRESS INTO THE AFTERNOON HRS...MAIN
CONCERNS REMAIN FOCUSED ON TWO AREAS WITH THE FIRST BEING POSSIBLE
SEVERE STORMS FOR AREAS THAT DO IN FACT BREAK INTO THE WARM
SECTOR PRIOR TO HEAVY RAINS MOVING IN...AND THE SECOND OBVIOUSLY
CENTERED ON THE DEVELOPING FLASH FLOOD THREAT.
FIRST FOR THE SEVERE THREAT...LATEST VIS SATELLITE IMAGERY SHOWING
JUST HIGH CIRRUS ACROSS THE EASTERN ZONES THIS HR WITH PLENTY OF
FILTERED SUN MAKING ITS WAY TO THE SURFACE. MAIN CLOUD SHIELD
ASSOCIATED WITH HEAVY RAINS STILL TO THE WEST THIS HR BUT MAKING
STEADY PROGRESS EAST. LATEST RUC ANALYSIS SHOWS A SLOW MOVING
SHORTWAVE WORKING THROUGH THE AREA CURRENTLY...WITH THIS FEATURE
EXPECTED TO EXIT OFF TO OUR EAST WITHIN THE NEXT FEW HRS. FCST
925 AND 850 MB WINDS SHOW VERY FAIRLY WEAK SOUTHEASTERLY FLOW
THROUGH THIS AFTERNOON LENDING CONCERN THAT AFOREMENTIONED FRONTAL
BOUNDARY WILL HAVE A DIFFICULT TIME ADVANCING NORTH THROUGH THE
REMAINDER OF THE DAY. MAIN ISSUES PREVENTING WIDESPREAD DEEP MOIST
CONVECTION STEMS FROM OVERALL LACK OF INSTABILITY BASED ON
BETTER DEWPOINTS/HEATING REMAINING TO THE SOUTH. BIG WILD CARD
WILL BE WHETHER THIS FRONT IS ABLE TO MOVE NORTH INTO THE SOUTHERN
CATSKILLS/LWR WYOMING VLY/AND POCONOS LATER TODAY. THAT
SAID...BEST POTENTIAL SEEMS TO BE FOCUSED OVER THESE AREAS WHERE
ISOLATED STRONG WILDS APPEAR TO BE THE BIGGEST THREAT.
MOVING ON...FOCUS WILL BECOME MORE HYDRO FOCUSED AS STRONG UPPER
WAVE TAPPING AN INCREASING MOIST AND TROPICAL AIRSTREAM MIGRATES
EAST WITH TIME. STRONG FORCING ARRIVING FROM THE MAIN MID-LEVEL
VORTICITY MAXIMUM WILL BE STRONGLY SUPPORTED BY A NOW DEVELOPING
COUPLED JET CIRCULATION WHICH WILL TARGET MUCH OF OUR FCST REGION
LATER TODAY INTO TONIGHT. AS THIS OCCURS...LOW-LEVEL JET WINDS ARE
PROGGED TO INCREASE TO NEAR 40 KTS AS THE THERMALLY DIRECT COUPLED
JET CIRCULATION MATURES WITH TIME. AS THIS OCCURS...AN AIRMASS
WITH TROPICAL ORIGINS /SEE LATEST BLENDED TPW SATELLITE IMAGERY/
WITH PWAT VALUES NOW APPROACHING 2" JUST SOUTH OF OUR FCST REGION
WILL ADVANCE NORTH AND OVER THE FRONTAL BOUNDARY JUST TO OUR
SOUTH /I.E. MADDOX FRONTAL TYPE FF EVENT?/. FOR WHAT ITS
WORTH...WFO CTP ALREADY ISSUING ACTIVE FLOOD STATEMENTS AND MAKING
REFERENCE TO 3"/HR RAINFALL RATES. OBVIOUSLY AS THIS AIRMASS WORKS
OVER THE AREA COMBINED WITH STRONG SYNOPTIC SUPPORT ALOFT...FLASH
FLOODING DEFINITELY A LIKELIHOOD LATER TODAY/TONIGHT. AS A
RESULT...NO CHANGES TO THE CURRENT FLASH FLOOD PRODUCT ANTICIPATED
ON THE DAYSHIFT.
620 AM UPDATE...AREAS OF DENSE FOG CURRENTLY EXTENDS ACROSS
THE TWIN TIERS AS CI OVERSPREADS THE REGION. HIGH CLOUDS MAY
PREVENT SOME MIXING INITIALLY EARLY THIS MORNING THEREFORE KEPT
FOG IN THE FORECAST UNTIL MID MORNING. NO OTHER CHANGES.
AT 445 AM...SKIES WERE MAINLY CLEAR OVER THE REGION WITH DENSE
VALLEY FOG ACROSS THE TWIN TIERS.
MODELS ARE IN MUCH BETTER AGREEMENT THIS MORNING WITH SYSTEM
LIFTING NORTHEAST FROM THE OHIO VALLEY. UPPER LEVEL TROF WILL
ADVANCE EASTWARD TOWARD THE REGION TODAY BRINGING WIDESPREAD
SHOWERS AND EMBEDDED THUNDERSTORMS INTO THE AREA FROM SOUTHWEST TO
NORTHEAST FROM EARLY THIS AFTERNOON THROUGH THIS EVENING.
SYSTEM WILL HAVE THE CAPACITY FOR LOCALIZED HEAVY RAINFALL AS
AIRMASS IS VERY MOIST WITH PWATS OF 1.50-2.00 INCHES. JET DYNAMICS
ARE ALSO VERY IMPRESSIVE WITH DOUBLE JET STRUCTURE RESULTING IN
STRONG UPPER LEVEL DIVERGENCE THIS EVENING THROUGH THE OVERNIGHT
PERIOD. MODELS ARE IN MUCH BETTER AGREEMENT WITH SFC LOW TRACK
TAKING FEATURE FROM CENTRAL PA NORTHEAST INTO THE NORTHERN TIER
OF PA THEN INTO THE WESTERN CATSKILLS. WITH THIS TRACK FEEL THE
MOST LIKELY AREA FOR HEAVY RAINFALL WILL BE ACROSS NE PA INTO THE
WESTERN CATSKILLS WHERE LOW LEVEL JET AND BEST MOISTURE ADVECTION
WILL RESIDE. A GENERAL 1 TO 2 INCHES OF RAINFALL IS LIKELY OVER
THE REGION WITH LOCALIZED AMOUNTS AROUND 3 INCHES OR GREATER POSSIBLE.
SEVERE WEATHER LATER TODAY AND INTO THIS EVENING IS STILL A
POSSIBILITY BUT WEAK LAPSE RATES AND MID LEVEL WIND FIELDS IS A
LIMITING FACTOR. SHEAR WILL INCREASE LATER TODAY THROUGH THIS
EVENING AS UPPER LEVEL TROF APPROACHES AND IF ENOUGH DESTABILIZATION
OCCURS A FEW CELLS COULD PRODUCE DAMAGING WINDS. THE BEST AREA FOR
THIS ACTIVITY WOULD BE THE EASTERN CWA WHERE CAPE VALUES MAY BE
MORE SIGNIFICANT.
WILL CONTINUE WITH FLASH FLOOD WATCH FOR THE ENTIRE AREA THIS
AFTERNOON THROUGH TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
UPPER LEVEL TROF WILL DEEPEN OVER THE REGION DURING THIS PERIOD
WITH SFC LOW PRES INITIALLY LIFTING NORTHEAST INTO SOUTHERN
QUEBEC THEN RETROGRADING BACK UNDER THE UPPER LEVEL FEATURE.
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE
PERIOD WITH THE MOST WIDESPREAD COVERAGE EXPECTED DURING THE
DAYLIGHT HOURS ENHANCED BY DIURNAL INSTABILITY.
MAX TEMPS BOTH FRIDAY AND SATURDAY WILL GENERALLY RANGE IN THE
70S WITH VALLEY AREAS IN NE PA AROUND 80.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
400 AM EDT UPDATE...
PREVIOUS FORECAST IS IN GOOD SHAPE. MINOR CHANGES TO THE TEMPS WERE
MADE. KEPT POPS THE SAME.
420 PM WED UPDATE... CONCERNS CONTINUE TO RISE THIS AFTERNOON FOR
A POTENTIAL SIGNIFICANT HYDROLOGIC EVENT FOR PORTIONS OF THE EAST
COAST LATE THIS WEEKEND INTO MIDWEEK AS A STAGNANT NORTH-SOUTH
MERIDIONAL FLOW PATTERN TRANSPORTS LARGE AMOUNTS OF TROPICAL
MOISTURE NORTH INTO THE MIDDLE ATLANTIC AND NEW ENGLAND REGIONS.
LATEST 12Z GEFS STANDARDIZED ANOMALY GRAPHICS CONTINUE TO
ADVERTISE AN INCREASINGLY BLOCKY PATTERN WITH VERY AMPLIFIED HIGH
PRESSURE DEVELOPING ACROSS THE INTERMOUNTAIN WEST WITH ADDITIONAL
DOWNSTREAM RIDGING EXPECTED TO STRENGTHEN OVER TIME ACROSS THE
NORTHERN ATLANTIC. AS HAS BEEN ADVERTISED OVER THE PAST FEW
DAYS...VERY DEEP TROUGHING WILL DEVELOP WEST OF OUR FORECAST
REGION WITH THE ASSOCIATED TROUGH AXIS EXPECTED TO EXTEND WELL
SOUTH INTO THE GULF OF MEXICO BY EARLY WEEK. AS AN INDICATION OF
HOW ANOMALOUS THE DEVELOPING PATTERN IS EXPECTED TO BE...LATEST
WPC EXTENDED DISCUSSIONS NOW SPEAKING OF POSSIBLE ALL-TIME RECORD
HIGHS ACROSS PORTIONS OF THE DESERT SOUTHWEST. MEANWHILE FOR AREAS
CLOSER TO US...PWAT ANOMALY GRAPHICS ARRIVING THIS AFTERNOON
SHOWING STRONG TROPICAL MOISTURE CONNECTIONS TO THE SOUTH
ATLANTIC/CARIBBEAN...WITH AN ADDITIONAL COMPONENT EXPECTED TO
ARRIVE FROM THE EAST-CENTRAL PACIFIC. THE CONVERGENCE OF BOTH LOW
/MID-LEVEL AIR STREAMS WILL FUNNEL ITS WAY NORTH WITH TIME
RESULTING IN WIDESPREAD RAIN/POTENTIALLY HEAVY RAIN DEVELOPMENT. A
LITTLE TOO EARLY TO DIVE INTO EXACT DETAILS THIS FAR OUT BUT
CONFIDENCE CONTINUES TO INCREASE THAT FLOODING RAINS ARE POSSIBLE
SOMEWHERE ALONG THE ATLANTIC SEABOARD BEGINNING THIS WEEKEND AND
LASTING THROUGH AT LEAST MIDWEEK. IN ANY EVENT...HAVE CONTINUED
LIKELY POPS THROUGH THE PERIOD AND WILL CONTINUE TO ADVERTISE
HEAVY RAIN POTENTIAL IN THE HWO PRODUCT.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
700 AM EDT UPDATE...
DENSE FOR HAS SETTLED OVER THE REGION THIS MORNING WITH LIGHT AND
VARIABLE WINDS. EXPECT FOG TO START TO MIX OUT AROUND 12Z THIS
MORNING. WINDS WILL REMAIN LIGHT THROUGH THE MORNING HOURS.
SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE AREA THIS
AFTERNOON AND EVENING RESULTING IN MVFR. ISOLATED IFR CIGS WILL BE
ATTENDANT WITH THE HEAVIER STORMS BUT CONFIDENCE IS LOW ON THE
TIMING THEREFOR KEPT THE MENTION OF IFR OUR OF THE TAFS AT THIS
TIME. EMBEDDED THUNDERSTORMS WILL BE POSSIBLE WITH THESE SHOWERS.
CONFIDENCE WITH THE TIMING OF THESE THUNDERSTORMS ARE LOW AND
CHOSE TO KEEP THEM OUT OF THE TAF AT THE MOMENT AS WELL. THESE
SHOWERS ARE EXPECTED TO START TO MOVE OUT OF THE AREA FRIDAY
MORNING TOWARDS THE NORTH...HOWEVER ANOTHER ROUND OF SHOWERS ARE
EXPECTED FRIDAY AFTERNOON.
OUTLOOK...FRI THROUGH SUN...
FRI...MVFR POSSIBLE IN AFTERNOON SHWRS/STORMS.
SAT/SUN/MON...MVFR/IFR RESTRICTIONS POSSIBLE IN RA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
AFTERNOON FOR PAZ038>040-043-044-047-048-072.
NY...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
AFTERNOON FOR NYZ009-015>018-022>025-036-037-044>046-
055>057-062.
&&
$$
SYNOPSIS...RRM
NEAR TERM...CMG/RRM
SHORT TERM...RRM
LONG TERM...CMG/KAH
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1051 AM EDT THU JUN 27 2013
.SYNOPSIS...
A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY
AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME
SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND
WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WATER VAPOR IMAGERY DISPLAYS A SHORTWAVE TROUGH NEAR NE OH THIS
MORNING. JUST TO THE EAST OF THE CUSP...WHICH IS FOUND ON THE
WESTERN SIDE OF THE UPPER LEVEL CIRCULATION IS FOUND AT THE SURFACE
AN AREA OF LOW PRESSURE...WHICH CAN ALSO BE SEEN IN RADAR LOOPS AND
SURFACE ANALYSIS AS A WEAK AREA OF LOW PRESSURE. LATEST IR AND
VISIBLE SATELLITE IMAGERY SHOWS COOLING CLOUD TOPS ASSOCIATED WITH
THE WARM CONVEYOR BELT WHICH WILL CONTINUE TO STREAM MOISTURE
NORTHWARD AHEAD OF THE UPPER LEVEL SHORTWAVE. THIS WILL FOCUS THE
GREATEST MOISTURE...AND COUPLED WITH THE BEST ISENTROPIC LIFT AND
SYNOPTIC LIFT WILL FOCUS THE HEAVIEST RAIN THROUGH THE DAYTIME
ACROSS THE SOUTHERN TIER. DAYTIME HEATING MAY TRIGGER SHOWERS AND AN
ISOLATED THUNDERSTORM AHEAD OF THE MAIN SLUG OF RAINFALL WHICH WILL
ONLY SLOWLY WORK ITS WAY NORTHWARD TODAY.
THE 00Z/06Z RUNS OF THE NAM...AND TO A LESSER EXTENT THE 00Z
GFS/UKMET/EURO KEEP THE MAJORITY OF THE PRECIPITATION IN FAR
SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE DAY. MEANWHILE THE RGEM
AND SEVERAL HRRR RUNS ARE FURTHER NORTH...PERHAPS KEYING ON A SUBTLE
SURFACE CONVERGENCE BOUNDARY SOUTH OF LAKE ONTARIO. RECALLING AN
EVENT A WEEK AGO WHERE THE OUTLYING RGEM DID HAVE THE BEST HANDLE ON
A SIMILAR SYSTEM...WILL CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE
A BLEND OF BOTH CAMPS OF GUIDANCE. EARLY MORNING RADAR TREND TEND TO
SUPPORT THE HRRR/RGEM SOLUTIONS WHICH BRING AN AREA OF RAIN ACROSS
WESTERN NEW YORK TODAY.
FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH
STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF.
RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY
TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE
ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE
FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL
BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS
(00Z NAM/RGEM/GFS/EURO AND 03Z SREF) IS FAIRLY CONSISTENT IN PUTTING
THE STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES
REGIONS FOR TONIGHT. THIS SAID...06Z RUNS OF THE NAM/GFS HAVE
SHIFTED A BIT SOUTH AND EAST...BUT GIVEN THEY HAVE NOT BEEN
VERIFYING WELL UP TO THIS POINT...WILL NOT GIVE THESE SOLUTIONS
TOO MUCH WEIGHT.
A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE
POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL
GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN
SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING
UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR
SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE
FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST
RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE
BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT
AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON
THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING
FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON DUE TO
EXTREMELY SLOW STORM MOTION. WHILE QPFS ARE LESS ELSEWHERE...THERE
STILL IS A POTENTIAL...ESPECIALLY CONSIDERING RAINFALL AMOUNTS IN
EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL BUFFALO CREEKS TO
BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES UP...AND BASED ON
THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP THE TIMING FOR
THE EASTERN LAKE ONTARIO SECTION OF THE WATCH.
OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE
TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH
ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE
FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY
CONDITIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD
AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE
LOW LIFT VERY SLOWLY TO THE NORTH.
ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE
IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH
TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED
CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD
SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE.
THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL.
ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY)
WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED
BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET
STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW
ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY
RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE
NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL
FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW.
IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE
QUARTERS OF AN INCH OF RAIN ON FRIDAY.
AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT
THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL
FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN
NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND
VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS
AREA.
REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER
MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT
EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM
CONVECTION.
SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN
PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A
FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE
POSSIBILITY OF LIMITED SUNSHINE.
EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS
PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT
OF THE 60S DUE TO THE ANTICIPATED RAINFALL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE
EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS
TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING
MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN
RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH
RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE
TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT
LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND
NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW
NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE
UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF
THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO
OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST
PERIOD.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
12Z TAFS...LINGERING FOG WILL LIFT QUICKLY AS CLOUDS BUILD ACROSS
THE REGION. AFTER THIS...ATTENTION TURNS TO AN INCREASING CHANCE
FOR SHOWERS TODAY AND TONIGHT. SOME OF THESE COULD BE FAIRLY
HEAVY...WITH SOME EMBEDDED THUNDERSTORMS. GIVEN THE ISOLATED
NATURE...AND UNCERTAINTY IN TIMING OF THE HEAVIEST
SHOWERS...LARGELY KEEP THE TSTMS OUT OF THE TAF...WITH UPSTREAM
CONDITIONS KEYING ANY POSSIBLE ADDITION OF TSTMS. AS WINDS BECOME
MORE NE...AND AIR MOISTENS...EXPECT LOWERING CIGS AND VSBY THIS
EVENING AND OVERNIGHT.
OUTLOOK...
FRIDAY...MVFR IN SHOWERS.
SATURDAY THROUGH MONDAY...MAINLY VFR WITH A CHANCE OF MAINLY
AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR.
&&
.MARINE...
LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY
WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA
CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL
DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
EVENING FOR NYZ006>008.
FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
AFTERNOON FOR NYZ001>005-010>014-019>021-085.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/THOMAS
SHORT TERM...TJP
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
651 AM EDT THU JUN 27 2013
.SYNOPSIS...
A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY
AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME
SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND
WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RAIN IS ON THE WAY FOR WESTERN NEW YORK...BUT IT WILL TAKE ITS
TIME. THROUGH DAYBREAK...RADAR SHOWS SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS WORKING INTO WESTERN PENNSYLVANIA. RAIN WILL
SPREAD INTO WESTERN PORTIONS OF THE SOUTHERN TIER THROUGH MID-
MORNING...THEN GRADUALLY INTO THE REST OF WESTERN NEW YORK THROUGH
THIS EVENING.
THE MAIN CAUSE OF THE PRECIPITATION WILL BE A SLOWLY APPROACHING
UPPER LEVEL TROF. WATER VAPOR SHOWS THIS IS CURRENTLY AN OPEN WAVE
AT AROUND 500 MB...BUT IT IS FORECAST TO CLOSE OFF AS IT MERGES WITH
A LARGE UPPER LEVEL LOW THROUGH FRIDAY MORNING. WHILE MODEL
GUIDANCE IS IN GENERAL AGREEMENT ON THIS PROGRESSION...IT IS STILL A
TRICKY FORECAST GIVEN SUBTLE DIFFERENCES WHICH LEAD TO FAIRLY LARGE
DIFFERENCES IN QPF FORECASTS. 00Z/06Z RUNS OF THE NAM...AND TO A
LESSER EXTENT THE 00Z GFS/UKMET/EURO KEEP THE MAJORITY OF THE
PRECIPITATION IN FAR SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE
DAY. MEANWHILE THE RGEM AND SEVERAL HRRR RUNS ARE FURTHER
NORTH...PERHAPS KEYING ON A SUBTLE SURFACE CONVERGENCE BOUNDARY
SOUTH OF LAKE ONTARIO. RECALLING AN EVENT A WEEK AGO WHERE THE
OUTLYING RGEM DID HAVE THE BEST HANDLE ON A SIMILAR SYSTEM...WILL
CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE A BLEND OF BOTH CAMPS
OF GUIDANCE. EARLY MORNING RADAR TREND TEND TO SUPPORT THE
HRRR/RGEM SOLUTIONS WHICH BRING AN AREA OF RAIN ACROSS WESTERN NEW
YORK TODAY.
FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH
STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF.
RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY
TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE
ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE
FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL
BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS
(00Z NAM/RGEM/GFS/EURO AND 03Z SREF) IS FAIRLY CONSISTENT IN PUTTING
THE STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES
REGIONS FOR TONIGHT. THIS SAID...06Z RUNS OF THE NAM/GFS HAVE
SHIFTED A BIT SOUTH AND EAST...BUT GIVEN THEY HAVE NOT BEEN
VERIFYING WELL UP TO THIS POINT...WILL NOT GIVE THESE SOLUTIONS
TOO MUCH WEIGHT.
A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE
POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL
GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN
SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING
UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR
SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE
FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST
RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE
BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT
AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON
THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING
FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON DUE TO
EXTREMELY SLOW STORM MOTION. WHILE QPFS ARE LESS ELSEWHERE...THERE
STILL IS A POTENTIAL...ESPECIALLY CONSIDERING RAINFALL AMOUNTS IN
EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL BUFFALO CREEKS TO
BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES UP...AND BASED ON
THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP THE TIMING FOR
THE EASTERN LAKE ONTARIO SECTION OF THE WATCH.
OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE
TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH
ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE
FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY
CONDITIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD
AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE
LOW LIFT VERY SLOWLY TO THE NORTH.
ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE
IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH
TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED
CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD
SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE.
THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL.
ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY)
WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED
BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET
STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW
ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY
RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE
NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL
FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW.
IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE
QUARTERS OF AN INCH OF RAIN ON FRIDAY.
AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT
THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL
FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN
NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND
VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS
AREA.
REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER
MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT
EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM
CONVECTION.
SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN
PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A
FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE
POSSIBILITY OF LIMITED SUNSHINE.
EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS
PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT
OF THE 60S DUE TO THE ANTICIPATED RAINFALL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE
EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS
TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING
MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN
RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH
RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE
TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT
LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND
NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW
NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE
UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF
THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO
OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST
PERIOD.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
12Z TAFS...LINGERING FOG WILL LIFT QUICKLY AS CLOUDS BUILD ACROSS
THE REGION. AFTER THIS...ATTENTION TURNS TO AN INCREASING CHANCE
FOR SHOWERS TODAY AND TONIGHT. SOME OF THESE COULD BE FAIRLY
HEAVY...WITH SOME EMBEDDED THUNDERSTORMS. GIVEN THE ISOLATED
NATURE...AND UNCERTAINTY IN TIMING OF THE HEAVIEST
SHOWERS...LARGELY KEEP THE TSTMS OUT OF THE TAF...WITH UPSTREAM
CONDITIONS KEYING ANY POSSIBLE ADDITION OF TSTMS. AS WINDS BECOME
MORE NE...AND AIR MOISTENS...EXPECT LOWERING CIGS AND VSBY THIS
EVENING AND OVERNIGHT.
OUTLOOK...
FRIDAY...MVFR IN SHOWERS.
SATURDAY THROUGH MONDAY...MAINLY VFR WITH A CHANCE OF MAINLY
AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR.
&&
.MARINE...
LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY
WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA
CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL
DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
EVENING FOR NYZ006>008.
FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
AFTERNOON FOR NYZ001>005-010>014-019>021-085.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...TJP
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
356 AM EDT THU JUN 27 2013
.SYNOPSIS...
A SLOW MOVING AREA OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY
AND TONIGHT...BRINGING A PERIOD OF STEADY RAIN...HEAVY IN SOME
SPOTS. THE WEATHER PATTERN WILL REMAIN UNSETTLED THROUGH THE WEEKEND
WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RAIN IS ON THE WAY FOR WESTERN NEW YORK...BUT IT WILL TAKE ITS TIME. RADAR
ALREADY SHOWS SHOWERS EXPANDING ACROSS OHIO WITH THIS AREA SLOWLY
PUSHING TOWARD OUR REGION. RAIN WILL GRADUALLY SPREAD INTO WESTERN
PORTIONS OF THE SOUTHERN TIER THROUGH MID- MORNING...THEN
GRADUALLY INTO THE REST OF WESTERN NEW YORK THROUGH THIS EVENING.
THE MAIN CAUSE OF THE PRECIPITATION WILL BE A SLOWLY APPROACHING
UPPER LEVEL TROF. WATER VAPOR SHOWS THIS IS CURRENTLY AN OPEN WAVE
AT AROUND 500 MB...BUT IT IS FORECAST TO CLOSE OFF AS IT MERGES WITH
A LARGE UPPER LEVEL LOW THROUGH FRIDAY MORNING. WHILE MODEL
GUIDANCE IS IN GENERAL AGREEMENT ON THIS PROGRESSION...IT IS STILL A
TRICKY FORECAST GIVEN SUBTLE DIFFERENCES WHICH LEAD TO FAIRLY LARGE
DIFFERENCES IN QPF FORECASTS. 00Z/06Z RUNS OF THE NAM...AND TO A
LESSER EXTENT THE 00Z GFS/UKMET/EURO KEEP THE MAJORITY OF THE
PRECIPITATION IN FAR SOUTHERN PORTIONS OF THE CWA FOR MUCH OF THE
DAY. MEANWHILE THE RGEM AND SEVERAL HRRR RUNS ARE FURTHER
NORTH...PERHAPS KEYING ON A SUBTLE SURFACE CONVERGENCE BOUNDARY
SOUTH OF LAKE ONTARIO. RECALLING AN EVENT A WEEK AGO WHERE THE
OUTLYING RGEM DID HAVE THE BEST HANDLE ON A SIMILAR SYSTEM...WILL
CONSIDER THE RGEM SOLUTION PLAUSIBLE AND USE A BLEND OF BOTH CAMPS
OF GUIDANCE. OVER THE NEXT FEW HOURS...RADAR TRENDS SHOULD HELP PIN
THINGS DOWN.
FOR TONIGHT...MODEL GUIDANCE IS IN A BIT BETTER AGREEMENT...WITH
STEADY RAINS LIKELY TO EXPAND AS THE LOW BECOMES MORE CLOSED OFF.
RAINS SHOULD BE HEAVY AT TIMES TONIGHT...WITH HEAVIEST RAINS LIKELY
TO BE NW OF THE 850 MB LOW AND UNDERNEATH THE UPPER TROF...WHERE
ELEVATED INSTABILITY WILL COMBINE WITH DEEP MOISTURE. PWATS ARE
FORECAST TO BE AROUND 1.75 INCHES TONIGHT...AND THIS COULD VERY WELL
BE REALIZED GIVEN THE SLOW MOVEMENT OF THE SYSTEM. MODEL CONSENSUS
(SREF/NAM/RGEM/GFS/EURO) IS FAIRLY CONSISTENT IN PUTTING THE
STEADIEST RAINS EAST OF LAKE ONTARIO AND IN THE FINGER LAKES REGIONS
FOR TONIGHT.
A FLOOD WATCH IS IN PLACE FOR ALL OF WESTERN NEW YORK...AND THE
POTENTIAL FOR FLOODING STILL EXISTS. IN ADDITION TO MODEL
GUIDANCE...WHICH SHOWS STORM TOTAL QPFS PUSHING 2 INCHES IN
SPOTS...THE SYNOPTIC PATTERN IS ALSO FAVORABLE GIVEN THE SLOW MOVING
UPPER LOW. ALTHOUGH RIVERS AND CREEKS HAVE SUBSIDED TO NEAR (OR
SLIGHTLY ABOVE) NORMAL...FLOWS ARE RUNNING ABOVE NORMAL IN THE
FINGER LAKES AND EASTERN LAKE ONTARIO REGIONS...WHERE THE HEAVIEST
RAINS ARE MOST LIKELY. ITS ALSO WORTH NOTING...THAT SOME SURFACE
BASED CONVECTION COULD DEVELOP EAST OF LAKE ONTARIO TODAY...OUT
AHEAD OF THE STEADIER RAINS WITH THE UPPER LOW. ANY AFTERNOON
THUNDERSTORMS COULD PRIME CONDITIONS THERE...AND ALSO BEAR WATCHING
FOR THE POSSIBILITY OF FLASH FLOODING THIS AFTERNOON. WHILE QPFS ARE
LESS ELSEWHERE...THERE STILL IS A POTENTIAL...ESPECIALLY CONSIDERING
RAINFALL AMOUNTS IN EXCESS OF 1.5 INCHES WOULD PROBABLY PUSH SEVERAL
BUFFALO CREEKS TO BANKFULL. FOR NOW...WILL KEEP ALL THE WATCHES
UP...AND BASED ON THE POTENTIAL FOR AFTERNOON THUNDERSTORMS MOVE UP
THE TIMING FOR THE EASTERN LAKE ONTARIO SECTION OF THE WATCH.
OTHERWISE...TEMPERATURES WILL VARY TODAY...MAINLY DEPENDING ON THE
TIMING OF THE SHOWERS. HIGHS SHOULD BE COOLEST SOUTH AND WEST...WITH
ANOTHER 80 DEGREE DAY LIKELY EAST OF ROCHESTER. LOWS SHOULD BE
FAIRLY UNIFORM IN THE MID 60S TONIGHT...GIVEN CLOUDY AND RAINY
CONDITIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
RATHER UNSETTLED WEATHER CONDITIONS WILL PREVAIL THROUGH THIS PERIOD
AS THE LOWER GREAT LAKES UPPER LEVEL TROUGH AND ATTENDANT SURFACE
LOW LIFT VERY SLOWLY TO THE NORTH.
ON FRIDAY...THE MODELS GENERALLY AGREE THAT THE SURFACE LOW WILL BE
IN PLACE OVER EASTERN NEW YORK DURING THE MORNING...THEN LIFT NORTH
TOWARD THE ST LAWRENCE RIVER DURING THE AFTERNOON. A DEEP LAYERED
CYCLONIC FLOW OF VERY MOIST AIR WILL RESULT IN WIDESPREAD
SHOWERS...WITH PERIODS OF MODERATE TO HEAVY RAIN STILL POSSIBLE.
THE NAM AND ECMWF SHOW TWO POSSIBLE BULLSEYES OF HEAVIER RAINFALL.
ONE IS ACROSS NORTHERN NEW YORK STATE (INCLUDING THE NORTH COUNTRY)
WHICH WILL BE CLOSEST TO THE SURFACE LOW AND WILL HAVE THE ADDED
BENEFIT OF ADDITIONAL LARGE LIFT IN THE LFQ OF AN UPPER LEVEL JET
STREAK THAT WILL BE ADVANCING NORTH ACROSS EASTERN NEW YORK AND NEW
ENGLAND. WILL ALSO HAVE TO BE ALERT FOR THE POSSIBILITY OF HEAVY
RAINFALL ACROSS WESTERN NEW YORK WHERE THE MODELS (ESPECIALLY THE
NAM AND ECMWF) ARE HINTING THAT A SECONDARY AREA OF LOW LEVEL
FRONTOGENETIC FORCING MAY SET UP BEHIND THE DEPARTING LOW.
IN TERMS OF BASIN AVERAGE QPF...LOOK FOR ANOTHER ONE THIRD TO THREE
QUARTERS OF AN INCH OF RAIN ON FRIDAY.
AS THE LOW SHIFTS NORTH INTO SOUTHERN QUEBEC FRIDAY NIGHT...EXPECT
THE HEAVIEST RAIN TO PULL AWAY WITH IT. THE AREA OF LOW LEVEL
FRONTOGENETIC FORCING IS FORECAST TO REMAIN IN PLACE ACROSS WESTERN
NEW YORK THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. IF THIS TREND
VERIFIES...ANOTHER 0.25 TO 0.5 INCH OF RAIN MAY FALL ACROSS THIS
AREA.
REGARDING THE POTENTIAL FOR THUNDERSTORMS...THE MODELS SHOW RATHER
MARGINAL INSTABILITY FRIDAY AND FRIDAY NIGHT. AS A RESULT...DO NOT
EXPECT A SIGNIFICANT CONTRIBUTION TO QPF TOTALS TO COME FROM
CONVECTION.
SATURDAY AND SATURDAY...THE GENERAL TROUGH IS FORECAST TO REMAIN IN
PLACE ACROSS THE EASTERN THIRD OF THE NATION. THIS WILL RESULT IN A
FEW MORE SHOWERS AND A BETTER CHANCE FOR SOME CONVECTION DUE TO THE
POSSIBILITY OF LIMITED SUNSHINE.
EXPECT BELOW AVERAGE TEMPERATURES TO BE THE RULE DURING THIS
PERIOD...ESPECIALLY ON FRIDAY WHEN READINGS MAY STRUGGLE TO GET OUT
OF THE 60S DUE TO THE ANTICIPATED RAINFALL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A SERIES OF SHORTWAVES DROPPING FROM THE CANADIAN PRAIRIES INTO THE
EXISTING UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL AMPLIFY THIS
TROUGH OVER THE WEEKEND INTO A FULL LATITUDE TROUGH ENCOMPASSING
MUCH OF THE EASTERN UNITED STATES. THIS TROUGH WILL REMAIN
RELATIVELY STEADY-STATE THROUGH THE WEEKEND BEFORE THE BERMUDA HIGH
RE-ASSERTS ITS DOMINANCE OVER THE WESTERN ATLANTIC...CAUSING THE
TROUGH TO RETROGRADE BACK TO THE MISSISSIPPI VALLEY/WESTERN GREAT
LAKES DURING THE FIRST HALF OF NEXT WEEK. FOR WESTERN AND
NORTH-CENTRAL NEW YORK...THIS MEANS TEMPERATURES JUST A HAIR BELOW
NORMAL THIS WEEKEND...HIGHS IN THE MID 70S...WILL WARM BACK INTO THE
UPPER 70S MONDAY WITH LOW TO MID 80S POSSIBLE AGAIN BY THE MIDDLE OF
THE WEEK. WITH THE PRESENCE OF THE UPPER LEVEL TROUGH AXIS JUST TO
OUR WEST...EXPECT DIURNAL INSTABILITY-DRIVEN AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS TO REMAIN A FEATURE THROUGH THE FORECAST
PERIOD.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
06Z TAFS...THE MAIN FORECAST CONCERN FOR THE REMAINDER OF THE
OVERNIGHT PERIOD WILL BE THE POSSIBLE DEVELOPMENT OF RADIATION FOG.
THE BEST CHANCE FOR FOG IS AT JHW...WITH A LESSER CHANCE FOR
RADIATION FOG ELSEWHERE GIVEN LARGER TEMP/DEW POINT SPREADS. WILL
CARRY IFR FOG IN JHW...WITH MVFR FOG AT ART. IN EACH CASE...PERIODS
OF LOWER FOG ARE POSSIBLE AS VSBY IS LIKELY TO VARY.
AFTER THIS...ATTENTION TURNS TO AN INCREASING CHANCE FOR SHOWERS
TODAY AND TONIGHT. SOME OF THESE COULD BE FAIRLY HEAVY...WITH SOME
EMBEDDED THUNDERSTORMS. GIVEN THE ISOLATED NATURE...AND UNCERTAINTY
IN TIMING OF THE HEAVIEST SHOWERS...LARGELY KEEP THE TSTMS OUT OF
THE TAF...WITH UPSTREAM CONDITIONS KEYING ANY POSSIBLE ADDITION OF
TSTMS. AS WINDS BECOME MORE NE...AND AIR MOISTENS...EXPECT
LOWERING CIGS AND VSBY THIS EVENING.
OUTLOOK...
FRIDAY...MVFR IN SHOWERS.
SATURDAY THROUGH MONDAY...MAINLY VFR WITH A CHANCE OF MAINLY
AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR.
&&
.MARINE...
LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NORTHERLY
WINDS TO PICK UP TONIGHT AND FRIDAY. CONDITIONS MAY APPROACH SCA
CRITERIA ALONG THE SOUTHERN SHORES. AFTER THIS WINDS WILL
DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
EVENING FOR NYZ006>008.
FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH FRIDAY
AFTERNOON FOR NYZ001>005-010>014-019>021-085.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...TJP
LONG TERM...WOOD
AVIATION...APFFEL
MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1023 PM EDT FRI JUN 28 2013
.SYNOPSIS...
THE POTENTIAL FOR HEAVY RAINFALL WILL INCREASE THROUGH THE WEEKEND
AS TROPICAL MOISTURE STREAMS INTO THE CAROLINAS. THE UNSETTLED
WEATHER WILL CONTINUE INTO MUCH OF NEXT WEEK AS AN UNUSUALLY DEEP
UPPER LEVEL LOW SITS WEST OF THE REGION...AND INTERACTS WITH BERMUDA
HIGH PRESSURE OFFSHORE.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1030 PM FRIDAY...THE LATEST HRRR RUNS AND UPSTREAM RADAR
COMPOSITES SUGGEST POPS NEED TO BE LOWERED ACROSS MUCH OF MY
FORECAST AREA. THE DEVELOPMENT OF AN MCS ALONG AN EAST-WEST ORIENTED
OUTFLOW BOUNDARY ACROSS THE SOUTHERN PIEDMONT OF NC IS LIKELY
RESPONSIBLE FOR THE RELATIVE LACK OF CONVECTION ACROSS WESTERN AND
CENTRAL SOUTH CAROLINA AS THE STRONG UPWARD MOTION WITHIN THE MCS
HAS TO BE BALANCED BY CORRESPONDING SUBSIDENT MOTION AROUND THE
PERIPHERY. THERE ARE STILL THUNDERSTORMS DIRECTLY ASSOCIATED WITH
THE INCOMING SHORTWAVE DISTURBANCE ALOFT JUST WEST OF ANDERSON
SC...BUT THIS ACTIVITY HAS A LONG WAY TO GO BEFORE IT COULD
CONCEIVABLY AFFECT THE EASTERN CAROLINAS.
THE NORTH CAROLINA MCS SHOULD REMAIN NORTH OF MOST OF MY FORECAST
AREA OVERNIGHT...PERHAPS SCRAPING BY THE NORTHERN PORTIONS OF
ROBESON COUNTY IN A FEW HOURS. THE POPS REMAINING IN THE FORECAST
ARE MAINLY LATE TONIGHT AND ARE FOR THE POSSIBLE DEVELOPMENT OF NEW
CONVECTION WITH THE APPROACHING DISTURBANCE. NO SIGNIFICANT CHANGES
HAVE BEEN MADE TO TEMPERATURE FORECASTS. PREVIOUS DISCUSSION FROM
730 PM FOLLOWS...
A ZONE OF MID-LEVEL DRY AIR BETWEEN TWO SHORTWAVES HAS BROUGHT A
TEMPORARY LULL IN CONVECTIVE ACTIVITY ACROSS THE EASTERN CAROLINAS
TODAY. THIS LULL SHOULD COME TO AN END OVER THE NEXT SEVERAL HOURS
AS A MODEST SHORTWAVE CURRENTLY EXTENDING FROM WESTERN NC INTO
CENTRAL GEORGIA AND ALABAMA PUSHES EAST INTO THE CAROLINAS.
RADAR SHOWS A SQUALL LINE EXTENDING ACROSS NORTH-CENTRAL NORTH
CAROLINA FROM THE VA BORDER SOUTHWARD TO NEAR SOUTHERN PINES. THIS
ACTIVITY IS PROGRESSING MAINLY EAST AND SHOULD MOVE JUST NORTH OF
LUMBERTON BETWEEN 8-9 PM...BUT COULD SCRAPE THE NORTHERN HALVES OF
BLADEN AND PENDER COUNTIES BETWEEN 9-11 PM. WHAT I AM MORE CONCERNED
ABOUT IS NEW CONVECTIVE ACTIVITY DEVELOPING ACROSS WESTERN SOUTH
CAROLINA ASSOCIATED WITH THE MAIN SHORTWAVE ALOFT. LIKE LAST NIGHT
THE HOURLY HRRR RUNS ARE NOT INITIALIZING PERFECTLY BUT MOST PAINT A
STORY OF THUNDERSTORM ACTIVITY INCREASING ACROSS THE PEE DEE REGION
OF EASTERN SOUTH CAROLINA LATE THIS EVENING...SPREADING TO THE COAST
OF BOTH SOUTH AND NORTH CAROLINA AFTER MIDNIGHT. ALTHOUGH MY TIMING
ON THIS CONVECTION IS DIFFERENT FROM THE PREVIOUS FORECAST...MY
12-HOUR POPS ARE NOT SUBSTANTIALLY DIFFERENT: 50-70 PERCENT...
HIGHEST NORTH OF A LINE FROM LAKE CITY TO CONWAY TO WHITEVILLE AND
WILMINGTON.
CONFIDENCE THAT WE WILL HAVE CONVECTIVE ACTIVITY OVERNIGHT IS
BOLSTERED BY NOTING HOW LARGE FORECAST CAPE VALUES ARE ON MODEL
SOUNDINGS. EVEN ACCOUNTING FOR A STABLE SURFACE BOUNDARY LAYER...
LIFTING A PARCEL FROM 925 MB LATE THIS EVENING OVER FLORENCE ON A
RECENT RUC MODEL RUC SHOWS CAPE OVER 2000 J/KG WITH NO CONVECTIVE
INHIBITION. PRECIPITABLE WATER...WHICH HAD FALLEN TO 1.6 TO 1.7
INCHES THIS AFTERNOON...SHOULD RISE BACK TO 2+ INCHES AS THE 850 AND
700 MB LAYER MOISTENS OVERNIGHT.
NO CHANGES HAVE BEEN MADE TO LOW TEMPERATURE FORECASTS...STILL
EXPECTED TO RANGE FROM 73-75 INLAND WITH UPPER 70S NEAR THE COAST.
THIS IS NOT COINCIDENTALLY VERY NEAR OUR CURRENTLY OBSERVED
DEWPOINTS ACROSS THE AREA.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...JUNE IS GOING TO FINISH PRETTY MUCH HOW IT HAS
BEEN ALL MONTH...WARM...HUMID...AND UNSETTLED. IN FACT...THE WEEKEND
HAS THE POTENTIAL TO BE EVEN WETTER THAN MOST OF THE DAYS THIS
MONTH...AND THE LOCAL CLIMATE STATIONS WILL APPROACH OR EXCEED ALL
TIME-MONTHLY RAINFALL RECORDS FOR JUNE BEFORE THE PERIOD COMES TO AN
END.
HIGHLY ANOMALOUS PATTERN AT 500MB PERSISTS AND AMPLIFIES THROUGH THE
WEEKEND WITH A STRONG RIDGE CENTERED ACROSS THE SOUTHWEST AND A
DEEPENING TROUGH DROPPING ACROSS THE OH VLY. THIS AMPLIFICATION
FORCES A STALL IN THE ATMOSPHERIC RIVER...AND DRIVES THE TROUGH BACK
TO THE SW...CREATING HEIGHT ANOMALIES OF -3 SD`S ACROSS THE TN VLY.
WITH THE DEEPENING TROUGH AXIS DISPLACED WEST OF THE
CAROLINAS...THIS KEEPS DEEP SW FLOW ONGOING IN THIS AREA...AND PWATS
RISE TO 2 INCHES OR MORE...AROUND 2 SD`S ABOVE NORMAL. 5H TROUGH TO
THE WEST WITH DEEP MOISTURE PLUME ACROSS THE CAROLINAS CREATES AN
ENVIRONMENT FAVORABLE FOR HEAVY RAIN...BUT OTHER PARAMETERS AS WELL
SUGGEST A VERY WET PERIOD AHEAD FOR THE WKND.
700MB TROUGH WEST OF THE AREA SHARPENS...KEEPING THE GOMEX WIDE
OPEN AND HELPING TO ADVECT TREMENDOUS THETA-E RIDGING FROM 925MB
THROUGH 700MB. 850MB MOISTURE TRANSPORT VECTORS LENGTHEN AND POINT
RIGHT INTO THE COASTAL CAROLINAS...WITH STREAMLINES SUGGESTING
MORE AND MORE OF THAT GULF TAP. ADDITIONALLY...AS THE TROUGH
SHARPENS...ESPECIALLY SUNDAY...200MB JETTING INCREASES WITH THE
SOUTHEAST ALIGNING BENEATH THE RRQ WHICH WILL COMBINE WITH WEAK
500MB SHORTWAVES TO HELP DRIVE LIFT OVER THE AREA. WHILE
INSTABILITY WILL NOT BE EXTREME...MLCAPE OF 800-1200 J/KG WITH
LI`S AROUND -4...AND WARM CLOUD PROCESSES WILL DOMINATE THANKS TO
13000-14000 FT OF WARM CLOUD DEPTH...ENOUGH LIFT WILL CREATE THE
POTENTIAL FOR ISOLATED WET MICROBURSTS EVEN THOUGH HEAVY RAIN WILL
BE THE PREDOMINANT THREAT BOTH DAYS.
SO THE INGREDIENTS ARE IN PLACE TO SUPPORT AN EXTENDED WET
PERIOD...AND WPC HAS 1-3" OF QPF ACROSS THE AREA...ALTHOUGH ISOLATED
MUCH HIGHER TOTALS ARE LIKELY. THIS WILL OCCUR ACROSS A REGION THAT
HAS SEEN 150-300% OF NORMAL RAINFALL THE PAST TWO WEEKS...SO ANY
HEAVY RAINFALL WILL LIKELY CAUSE SOME FLOODING CONCERNS. AFTER
COLLABORATION WITH SURROUNDING OFFICES...HAVE CHOSEN TO HOLD OFF ON
ANY AREAL FLOOD WATCHES SINCE CONVECTION WILL BE SCATTERED TO
WIDESPREAD...MEANING CWA-BASIN RAINFALL WILL BE HIGHLY VARIABLE.
NEVERTHELESS...WILL NEED TO MONITOR FOR POTENTIAL FLOOD WATCHES AS
THE SYNOPTIC SETUP DEVELOPS IN TIME.
ONE FINAL NOTE ABOUT THE UPCOMING RAINFALL. THE CLIMATE STATIONS OF
FLORENCE, SC AND WILMINGTON, NC ARE BOTH APPROACHING MONTHLY RECORDS
FOR JUNE...AND WOULD NOT BE SURPRISED IF THESE RECORDS ARE ECLIPSED
BEFORE JULY BEGINS:
AT WILMINGTON...10.34" HAS FALLEN SO FAR...2.53" BEHIND THE JUNE
RECORD OF 12.87" (1962).
AT FLORENCE...7.89" HAS FALLEN THIS MONTH...1.30" BEHIND THE RECORD
OF 9.29" (1961).
SW WINDS THROUGH THE PERIOD WILL KEEP THE AIRMASS WARM...BUT TEMPS
WILL LIKELY REMAIN JUST BELOW NORMAL THANKS TO THE WIDESPREAD CLOUD
COVER AND CONVECTION. EXPECT HIGHS IN THE MID/UPR 80S BOTH
AFTNS...BUT WITH SIGNIFICANT VARIABILITY WITHIN SHOWERS/TSTMS. LOWS
AT NIGHT WILL FALL TO 70 OR A FEW DEGREES ABOVE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...HIGHLY AMPLIFIED MID LEVEL PATTERN WILL
CONTINUE THROUGH MOST OF THE EXTENDED PERIOD WHICH MEANS A
CONTINUATION OF THE UNSETTLED CONDITIONS. WPC HAS LIKELY POPS FOR
MONDAY THROUGH WEDNESDAY DURING THE DAYTIME HOURS WITH LOWER
VALUES FOR THE NIGHTTIME HOURS. THIS CERTAINLY SEEMS REASONABLE AS
THE RIVER OF MOISTURE WILL CONTINUE FROM THE SOUTH/SOUTHWEST.
THERE ARE INDICATIONS THE PATTERN WILL BREAK DOWN LATE IN THE
PATTERN WITH SLIGHT RIDGING BUILDING IN WHICH WARRANTS A SLIGHT
DOWNTURN IN POPS. WITH THE PATTERN CHANGING LITTLE...EXPECT
TEMPERATURES TO REMAIN STABLE WITH HIGHS A LITTLE BELOW NORMAL
WITH ALL THE MOISTURE AND OVERNIGHT LOWS A LITTLE ABOVE FOR THE
SAME REASON.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...HRRR MODEL APPEARS TOO PESSIMISTIC WITH THE EARLY
CONVECTION. LACK OF MODERATE CU INDICATES WE ARE STILL MILDLY
CAPPED...HOWEVER THAT WILL CHANGE AFTER 03Z AS DEEP MOISTURE INVADES
FROM THE WEST. LBT COULD GET BRUSHED EARLIER THAN THAT...WITH A
DECENT COMPLEX OF CONVECTION TO THE NORTH. TOWARD MORNING...DEEP
MOISTURE IN PLACE AT ALL TERMINALS...WITH SCATTERED TO NUMEROUS
CONVECTION EXPECTED...WITH ISOLATED THUNDER. CEILINGS WILL LOWER TO
MVFR WITH BRIEF IFR VISIBILITIES IN THE HEAVIER SHOWERS.
SATURDAY...EXPECT INTERMITTENT CONVECTION MOST OF THE DAY. SOME
DRYING ALOFT IS INDICATED AT THE INLAND TERMINALS...HOWEVER THIS MAY
JUST ALLOW MORE HEATING FOR POSSIBLE AFTERNOON THUNDERSTORMS. AGAIN
MVFR CEILINGS ARE EXPECTED THROUGHOUT MOST OF THE DAY.
EXTENDED OUTLOOK...ISOLATED/SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM FRIDAY...NO SIGNIFICANT CHANGES ARE NECESSARY TO THE
FORECAST. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...
BERMUDA HIGH PRESSURE WELL OFFSHORE IS HAVING LIMITED SUCCESS
PUSHING WESTWARD INTO WHAT HAS BECOME (FOR THE SEASON) A VERY STRONG
TROUGH OF LOW PRESSURE INLAND. BAROMETRIC PRESSURES ARE SURPRISINGLY
LOW FOR LATE JUNE...29.67 INCHES HERE IN WILMINGTON AS I TYPE. THE
PATTERN WILL NOT CHANGE OVERNIGHT WITH A HEALTHY FLOW OF SOUTHWEST
WINDS 20-25 KNOTS EXPECTED TO CONTINUE. THIS WIND HAS BUILT SEAS TO
7 FT AT THE FRYING PAN SHOALS BUOY...6 FT AT THE NEW WILMINGTON
"HARBOR" BUOY JUST SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER...AND 5
FT AT THE OCEAN CREST PIER WAVE GAUGE. THE BIGGEST CHANGE TO THE
FORECAST OVERNIGHT WAS TO INCREASE NEARSHORE WAVE HEIGHTS BASED
PRIMARILY ON THE REPORT FROM THE OCEAN CREST PIER REPORT.
SHOWERS JUST INLAND FROM GEORGETOWN DEVELOPED A COUPLE HOURS AGO
ALONG THE SEABREEZE...AND THESE SHOULD LARGELY DISSIPATE OVER THE
NEXT HOUR. AN UPPER LEVEL DISTURBANCE MOVING ACROSS THE WESTERN
CAROLINAS WILL APPROACH THE COASTAL WATERS LATE TONIGHT BRINGING
SCATTERED SHOWERS AND THUNDERSTORMS...MOST NUMEROUS NORTH OF CAPE
FEAR.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...EXTENDED SMALL CRAFT ADVISORY IN PLACE FOR
MUCH OF THE PERIOD...AND THERE IS A GOOD CHANCE IT WILL BE EXTENDED
IN TIME INTO NEXT WEEK. LARGE BERMUDA TYPE HIGH PRESSURE
OFFSHORE...AND AREA OF LOW PRESSURE STALLED INLAND...WILL KEEP A
PINCHED GRADIENT OVER THE WATERS. THIS DRIVES SW WINDS UP TO 20-25
KTS SATURDAY...AND ONLY SLIGHTLY WEAKER ON SUNDAY. SEAS WILL BE
DRIVEN PRIMARILY BY THESE WINDS...AND 4-7 FT WAVE HEIGHTS ARE
EXPECTED THROUGH THE PERIOD. ADDITIONALLY...SCATTERED TO
WIDESPREAD TSTMS BOTH DAYS WILL CREATE HEAVY RAINFALL...CAUSING
SEVERELY RESTRICTED VISIBILITY AT TIMES.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...STEADY STATE CONDITIONS FOR THE COASTAL
COMMUNITY THROUGH THE PERIOD WITH SOUTHERLY WINDS OF 15-20 KNOTS
PROBABLY CLOSER TO THE LOWER END OF THE RANGE. PATTERN WEAKENS
EVER SO SLIGHTLY WEDNESDAY WHICH TRANSLATES TO SLIGHTLY LOWER WIND
SPEEDS. WAVEWATCH GUIDANCE SHOWS 3-5 FEET MONDAY AND TUESDAY SO A
SCEC HEADLINE IS POSSIBLE. SIGNIFICANT SEAS DROP TO 2-4 FEET
WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EDT SUNDAY FOR
AMZ250-252-254-256.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...SHK
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1010 PM EDT FRI JUN 28 2013
.SYNOPSIS...
A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW
PRESSURE OVER THE REGION WILL RESULT IN SHOWERS AND THUNDERSTORMS
EACH DAY THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 PM FRIDAY...
THE SEVERE THUNDERSTORM WATCH EXPIRED AT 1000 PM. HOWEVER... ANOTHER
MID/UPPER LEVEL DISTURBANCE SET UP NEW CONVECTION ALONG THE OLD W-E
OUTFLOW BOUNDARY FROM NEAR CLT TO SW OF RDU IN THE PAST TWO HOURS. A
FLASH FLOOD THREAT CONTINUES ESPECIALLY IN STANLY COUNTY WHERE THE
FLASH FLOOD GUIDANCE IS LOW... CURRENTLY 2 INCHES IN 2 HOURS. THIS
WILL EASILY BE EXCEEDED WITH THE TRAINING OF SEVERAL LARGE STORMS
OVER THAT REGION BEFORE 1200 AM. RAINFALL RATES ARE NEARLY 2 INCHES
PER HOUR IN THESE STORMS. THIS MAY BECOME A VERY SERIOUS THREAT TO
LIFE AND PROPERTY IF THE CELLS REMAIN AS INTENSE AS THEY ARE
CURRENTLY... WITH SEVERAL MORE TO GO... ONE OVER WESTERN STANLY...
ONE OVER CABARRUS... AND THE LAST IN THE SERIES OVER CHARLOTTE.
EVERYONE IN STANLY COUNTY SHOULD TAKE THIS FLOOD THREAT VERY
SERIOUSLY AND HEAD ALL WARNINGS AND STATEMENTS. REMEMBER FLOODING IS
IMPOSSIBLE TO SEE AT NIGHT. DO NOT DRIVE IN THIS SITUATION.
FLASH FLOODING MAY BECOME AN ISSUE ALONG AND NORTH OF THE
W-E OUTFLOW FROM STANLY EAST THROUGH MONTGOMERY... PORTIONS OF
CHATHAM... LEE... WAKE... AND POSSIBLY DURHAM COUNTIES THROUGH 200
AM... DUE TO THE TRAINING OF STORMS ALONG AND NORTH OF THE OLD
OUTFLOW. THE HRRR SEEMS TO HAVE A FAIR GRIP ON THIS SITUATION...
WITH THE TRAINING OF STORMS POSSIBLE INTO THE FAY AND RDU AREAS...
BUT FOCUSED ON STANLY... MONTGOMERY... NW MOORE THROUGH 1200 AM.
&&
.SHORT TERM /SATURDAY AND SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...
FOR SATURDAY/SATURDAY NIGHT: CONTINUED WARM... DAMP... AND HUMID.
WE`LL REMAIN BENEATH CLIMATOLOGICALLY FAST CYCLONIC MID LEVEL FLOW
HEADING INTO THE WEEKEND. MODELS SHOW THE SURFACE TROUGH SHIFTING TO
THE COASTAL PLAIN SATURDAY MORNING WITH MARKEDLY LOWER SURFACE
THETA-E VALUES PUSHING INTO THE WRN FORECAST AREA. EXPECT TO SEE
SOME LINGERING PATCHY SHOWERS ALONG WITH AREAS OF STRATUS OVER THE
COASTAL PLAIN SATURDAY MORNING... BUT WEAK TO ABSENT DYNAMIC FORCING
FOR ASCENT AND TYPICALLY LOWER INSTABILITY AND LINGERING CINH THAT
TIME OF DAY WILL LIMIT COVERAGE/STRENGTH OF ANY CONVECTION DURING
THE MORNING... AND THE WRN PIEDMONT SHOULD REMAIN DRY THROUGH
MIDDAY. WITH THE INJECTION OF ENERGY DOWN ITS WEST SIDE... THE MID
LEVEL TROUGH IS EXPECTED TO DIG STRONGLY DOWN LAKE MICHIGAN INTO IN
AND THE WRN OH VALLEY THROUGH SATURDAY NIGHT... CAUSING A BACKING OF
MID LEVEL WINDS OVER NC TO A MORE SOUTHERLY DIRECTION AND A GRADUAL
STRENGTHENING AND BUILDING OF THE ATLANTIC ANTICYCLONE WESTWARD
TOWARD COASTAL NC. THIS WILL EFFECTIVELY LEAD TO DISSIPATION OF THE
ERN NC SURFACE TROUGH WHILE THE MORE SUBSTANTIAL FRONTAL ZONE
STRENGTHENS TO OUR WEST AND HIGH PW VALUES REBOUND BACK WESTWARD
THROUGH CENTRAL NC WITH AN ATTENDING RESURGENCE OF HIGHER 850 MB
THETA-E. THE NAM/GFS HANDLE THEIR PRECIP FIELDS DIFFERENTLY WITH THE
NAM HOLDING WIDESPREAD CONVECTION TO OUR EAST AND WEST UNTIL VERY
LATE SATURDAY NIGHT... WHILE THE GFS DEVELOPS CONVECTION WITH
HEATING SATURDAY AFTERNOON ESPECIALLY ALONG THE HIGHWAY 1
CORRIDOR... WHICH THEN PERSISTS THROUGH THE NIGHT AS THE 2+ INCH
PRECIP WATER VALUES SPREAD FROM THE COAST WESTWARD THROUGH ALL OF
CENTRAL NC. THE GFS`S PATTERN LOOKS TO BE A MORE REASONABLE
SCENARIO... WITH MORE SCATTERED DISCRETE CELLS IN THE FAR WRN
PIEDMONT (WHERE SURFACE DEW POINTS AND HENCE INSTABILITY WILL LIKELY
BE A BIT LOWER) TRENDING TO NUMEROUS CLUSTERS OF MULTICELLS ROUGHLY
EAST OF A LINE FROM ROXBORO TO SILER CITY TO WADESBORO (ATTENDING
THE GREATER INSTABILITY AND PW). THE BACKED STEERING FLOW AND
EXPECTED ORIENTATION OF CONVECTIVE BANDS WILL BRING ABOUT A CONCERN
FOR TRAINING ECHOES AND LOCALIZED URBAN AND STREET FLOODING AND
SWOLLEN CREEKS STARTING SATURDAY... ESPECIALLY CONSIDERING THE
IMPROVING UPPER DIVERGENCE OVER CENTRAL/ERN NC IN THE RIGHT ENTRANCE
REGION OF THE SOUTHERLY JET TO OUR NNW. AFTER MUCH COORDINATION AND
DISCUSSION... WILL NOT GO WITH A FLASH FLOOD WATCH AS YET... AS
WIDESPREAD HEAVY RAIN HAS YET TO MATERIALIZE IN THE ERN
PIEDMONT/SANDHILLS/COASTAL PLAIN WHERE THE MORE SANDY SOIL AND
FLATTER TERRAIN RESULTS IN SLOWER RUNOFF... BUT URBAN AREAS WILL
REMAIN VULNERABLE TO SOME FLOODING. WE WILL CONTINUE TO RE-EVALUATE
AND CONSIDER THIS RISK AS WE HEAD THROUGH THE WEEKEND. WILL HAVE A
GOOD CHANCE OF SHOWERS/STORMS WEST SATURDAY AFTERNOON/NIGHT WITH
LIKELY POPS ALONG/EAST OF THE AFOREMENTIONED LINE COVERING THE
CENTRAL/ERN CWA. DEEP LAYER SHEAR IS NOT TREMENDOUS BUT DOES IMPROVE
FURTHER TO 25-35 KTS... ALTHOUGH MODEL MLCAPE VALUES ONLY PEAK AT
800-1500 J/KG SATURDAY AFTERNOON ALONG/EAST OF HIGHWAY 1...
SUGGESTING PERHAPS A MORE MOIST-ADIABATIC PROFILE THAN WE`VE SEEN
LATELY. POTENTIALLY WEAKER UPDRAFTS ESPECIALLY ALOFT COULD LOWER THE
RISK OF SEVERE STORMS... BUT AGAIN THE DEEP WARM LAYER (LCL TO
FREEZING DEPTH NEAR 4 KM) AND PW NEAR 2 INCHES (WHICH IS NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL) SUPPORT A HEAVY RAIN THREAT WITH
WARM RAIN PROCESSES DOMINATING. HIGHS 87-91. LOWS 68-72. -GIH
THE WELL-ADVERTISED DEVELOPING TROUGH ALOFT WILL HAVE BECOME
STRONGLY AMPLIFIED AND ESTABLISHED OVER THE TN VALLEY THIS
PERIOD...BETWEEN A PAIR OF ANOMALOUSLY STRONG RIDGES OVER WESTERN N.
AMERICA AND THE WESTERN N. ATLANTIC. WHILE LOW LEVEL CONVERGENCE IN
ASSOCIATION WITH A LEE TROUGH/WEAK FRONT WILL HAVE DIMINISHED FROM
PREVIOUS DAYS...THE PATTERN OF PERTURBED SW TO SSW DEEP LAYER FLOW
WILL DRIVE NUMEROUS TO WIDESPREAD SHOWERS/STORMS...AMIDST A DEEP
MOIST AXIS CHARACTERIZED BY PRECIPITABLE WATER VALUES AROUND TWO
INCHES...SUNDAY AND LIKELY THROUGHOUT SUNDAY NIGHT. DEEP LAYER SHEAR
ON THE ORDER OF 25-30 KTS...TO PERHAPS 35 KTS OVER THE NW
PIEDMONT...WILL SUPPORT PRIMARILY MULTI-CELL BANDS CAPABLE OF
PRODUCING WET MICROBURSTS...AND TO A GREATER EXTENT LOCALIZED
FLOODING OWING THE ANOMALOUSLY HIGH PW/S. HIGHS GENERALLY IN THE MID
80S...AND LOWER 70S FOR LOWS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 PM FRIDAY...
CONTINUED...IF NOT INCREASINGLY...WET. THE LARGE SCALE
RIDGE/TROUGH/RIDGE CONFIGURATION ACROSS NOAM WILL GRADUALLY
RETROGRESS...WITH THE TROUGH DRIFTING WESTWARD INTO THE MS
VALLEY...THROUGH MID-LATE WEEK. THE PRESENCE AND PERSISTENCE OF THE
TROUGH WILL KEEP MUCH OF THE EASTERN US...INCLUDING CENTRAL NC...IN
A PATTERN OF PERTURBED AND DEEPLY MOIST SW TO SSW FLOW ALOFT -
FAVORABLE FOR ABOVE AVERAGE PRECIPITATION CHANCES...PARTICULARLY
THROUGH WEDNESDAY. THE PROLONGED STORMY PERIOD WILL FAVOR AN
INCREASING RISK OF FLOODING WITH EACH DAY THAT PASSES...WITH
OTHERWISE AN OCCASIONAL PRECIPITATION-LOADED WET MICROBURST FROM
LOOSELY ORGANIZED MULTI-CELL STORM MODES DRIVEN BY GENERALLY 20-25
KTS OF MID LEVEL FLOW. ASIDE FROM THE 00Z/28TH ECMWF...THE CONSENSUS
OF MEDIUM RANGE GUIDANCE...INCLUDING THE 00Z ECMWF ENSEMBLE
MEAN...INDICATES THE PATTERN RETROGRESSION WILL ALLOW THE WESTERN
ATLANTIC SUB-TROPICAL RIDGING TO EXPAND WESTWARD SUFFICIENTLY TO
LESSEN PRECIPITATION CHANCES/COVERAGE - FROM NUMEROUS/WIDESPREAD TO
SCATTERED - OVER EASTERN NC...INCLUDING THE RAH COASTAL PLAIN...BY
MID TO LATE WEEK. HIGHS MOSTLY IN THE MIDDLE 80S...WITH LOWS 70 TO
75.
&&
.AVIATION /00Z FRIDAY THROUGH WEDNESDAY/...
AS OF 745 PM FRIDAY...
A LINE OF SHOWERS AND THUNDERSTORMS WITH WIND GUSTS UP TO 30 OR 40
MPH ON AVERAGE WILL CONTINUE TO MOVE EAST AND AFFECT KRWI AND KFAY
THROUGH AROUND 03Z...AFTER WHICH TIME ADDITIONAL SCATTERED SHOWERS
AND ISOLATED WEAKER STORMS (THAN PREVIOUS ONES) WILL REDEVELOP AND
SPREAD NORTHEASTWARD ACROSS CENTRAL NC BETWEEN 03-07Z...IN
ASSOCIATION WITH A LIFT-INDUCING MID LEVEL IMPULSE. -MWS
OTHERWISE...BASED ON THE PERSISTENCE OF THE CURRENT PATTERN...AREAS
OF IFR/LIFR STRATUS ARE POSSIBLE AFTER 07Z TONIGHT AT RDU/RWI/FAY...
BUT ONCE AGAIN THE MODELS ARE PRESENTING CONFLICTING GUIDANCE
REGARDING THIS THREAT...SO CONFIDENCE IN OCCURRENCE OF A PREDOMINANT
IFR/LIFR CIG IS LOW. ANY SUCH STRATUS WOULD LIFT BY 14Z SATURDAY
MORNING...AND VFR CONDITIONS WOULD THEN HOLD THROUGH 18Z.
LOOKING BEYOND 00Z SUNDAY...SHOWERS/STORMS AND ATTENDANT MVFR OR
IFR CONDITIONS ARE EXPECTED TO BECOME MORE NUMEROUS SATURDAY
AFTERNOON INTO THE NIGHT... SO EXPECT INCREASINGLY POTENTIAL FOR
ADVERSE AVIATION CONDITIONS... ESPECIALLY AT RDU/RWI/FAY. WITH
MINIMAL CHANGE IN THE OVERALL PATTERN OVER THE CONUS... THE RISK FOR
DAILY NUMEROUS SUB-VFR SHOWERS AND STORMS (PRIMARILY FROM MID
AFTERNOON THROUGH MIDNIGHT) AND SHALLOW EARLY-MORNING IFR STRATUS IS
EXPECTED TO PERSIST INTO THE MIDDLE OF NEXT WEEK. -GIH
&&
.EQUIPMENT...
KRAX WSR-88D IS BACK IN OPERATIONAL SERVICE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BADGETT
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...MWS/HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
745 PM EDT FRI JUN 28 2013
.SYNOPSIS...
A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW
PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS EACH DAY THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
AS OF 245 PM FRIDAY...
THROUGH TONIGHT: LITTLE DOUBT THAT MOST IF NOT ALL OF THE AREA WILL
SEE SHOWERS/STORMS IN THE NEXT 18 HOURS. ACCORDING TO CURRENT
MESOANALYSES WE CONTINUE TO DESTABILIZE WITH MLCAPE ALREADY UP TO
1500-2500 J/KG AND MUCAPE AROUND 3000 J/KG. A BROKEN LINE OF SHOWERS
AND STORMS HAS FORMED OVER SOUTH-CENTRAL AND SW VA INTO THE NC
MOUNTAINS... AND THIS CONVECTION IS ON TRACK TO DROP ESE THROUGH
CENTRAL NC FROM MID AFTERNOON THROUGH THE EVENING. AS EXPECTED...
DEEP LAYER SHEAR CONTINUES TO IMPROVE TO 30-35 KTS... SUPPORTIVE OF
ORGANIZED CONVECTION... PARTICULARLY AS THIS INCOMING LINE FEEDS ON
A HIGHLY MOIST AND BUOYANT BOUNDARY LAYER WITH TEMPS NEAR 90 (THANKS
TO PLENTY OF HEATING THUS FAR) AND DEW POINTS IN THE LOW-MID 70S.
EXPECT CONVECTION TO BECOME MORE NUMEROUS AND STRENGTHEN AS IT TAPS
INTO THIS JUICIER AIR ALONG AND EAST OF THE HIGHWAY 1 CORRIDOR.
RECENT HRRR RUNS DEPICTED THIS SCENARIO FAIRLY WELL... BRINGING
SCATTERED STORMS INTO THE TRIAD TOWARD 19-20Z WHICH THEN CONGEAL
INTO AN ORGANIZED BAND OF STORM CLUSTERS HEADING EASTWARD THROUGH
04Z. STILL APPEARS THAT SEVERE WIND GUSTS WILL BE THE BIGGEST SEVERE
THREAT LATE TODAY INTO TONIGHT GIVEN THAT WE HAVE SOME DRIER AIR NOT
FAR OFF THE SURFACE AND DECENT D-CAPE AT OR OVER 800 J/KG. THE -10C
TO -30C CAPE IS NOT ESPECIALLY LARGE BUT HAS RISEN A BIT IN RECENT
HOURS TO NEAR 500 J/KG EAST OF THE HIGHER TERRAIN... THUS LARGE HAIL
REMAINS POSSIBLE BUT IS A SECONDARY THREAT. WILL CONTINUE TO TREND
POPS DOWN AND OUT GRADUALLY WEST TO EAST AFTER MIDNIGHT WITH LOSS OF
HEATING. FOG/STRATUS HAS BEEN TOUGH TO FORECAST THE LAST FEW DAYS
BUT WILL LEAN TOWARD PERSISTENCE... WITH BETTER COVERAGE EAST OF
HIGHWAY 1 WITHIN A VERY LIGHT SW FLOW.
FOR SATURDAY/SATURDAY NIGHT: CONTINUED WARM... DAMP... AND HUMID.
WE`LL REMAIN BENEATH CLIMATOLOGICALLY FAST CYCLONIC MID LEVEL FLOW
HEADING INTO THE WEEKEND. MODELS SHOW THE SURFACE TROUGH SHIFTING TO
THE COASTAL PLAIN SATURDAY MORNING WITH MARKEDLY LOWER SURFACE
THETA-E VALUES PUSHING INTO THE WRN FORECAST AREA. EXPECT TO SEE
SOME LINGERING PATCHY SHOWERS ALONG WITH AREAS OF STRATUS OVER THE
COASTAL PLAIN SATURDAY MORNING... BUT WEAK TO ABSENT DYNAMIC FORCING
FOR ASCENT AND TYPICALLY LOWER INSTABILITY AND LINGERING CINH THAT
TIME OF DAY WILL LIMIT COVERAGE/STRENGTH OF ANY CONVECTION DURING
THE MORNING... AND THE WRN PIEDMONT SHOULD REMAIN DRY THROUGH
MIDDAY. WITH THE INJECTION OF ENERGY DOWN ITS WEST SIDE... THE MID
LEVEL TROUGH IS EXPECTED TO DIG STRONGLY DOWN LAKE MICHIGAN INTO IN
AND THE WRN OH VALLEY THROUGH SATURDAY NIGHT... CAUSING A BACKING OF
MID LEVEL WINDS OVER NC TO A MORE SOUTHERLY DIRECTION AND A GRADUAL
STRENGTHENING AND BUILDING OF THE ATLANTIC ANTICYCLONE WESTWARD
TOWARD COASTAL NC. THIS WILL EFFECTIVELY LEAD TO DISSIPATION OF THE
ERN NC SURFACE TROUGH WHILE THE MORE SUBSTANTIAL FRONTAL ZONE
STRENGTHENS TO OUR WEST AND HIGH PW VALUES REBOUND BACK WESTWARD
THROUGH CENTRAL NC WITH AN ATTENDING RESURGENCE OF HIGHER 850 MB
THETA-E. THE NAM/GFS HANDLE THEIR PRECIP FIELDS DIFFERENTLY WITH THE
NAM HOLDING WIDESPREAD CONVECTION TO OUR EAST AND WEST UNTIL VERY
LATE SATURDAY NIGHT... WHILE THE GFS DEVELOPS CONVECTION WITH
HEATING SATURDAY AFTERNOON ESPECIALLY ALONG THE HIGHWAY 1
CORRIDOR... WHICH THEN PERSISTS THROUGH THE NIGHT AS THE 2+ INCH
PRECIP WATER VALUES SPREAD FROM THE COAST WESTWARD THROUGH ALL OF
CENTRAL NC. THE GFS`S PATTERN LOOKS TO BE A MORE REASONABLE
SCENARIO... WITH MORE SCATTERED DISCRETE CELLS IN THE FAR WRN
PIEDMONT (WHERE SURFACE DEW POINTS AND HENCE INSTABILITY WILL LIKELY
BE A BIT LOWER) TRENDING TO NUMEROUS CLUSTERS OF MULTICELLS ROUGHLY
EAST OF A LINE FROM ROXBORO TO SILER CITY TO WADESBORO (ATTENDING
THE GREATER INSTABILITY AND PW). THE BACKED STEERING FLOW AND
EXPECTED ORIENTATION OF CONVECTIVE BANDS WILL BRING ABOUT A CONCERN
FOR TRAINING ECHOES AND LOCALIZED URBAN AND STREET FLOODING AND
SWOLLEN CREEKS STARTING SATURDAY... ESPECIALLY CONSIDERING THE
IMPROVING UPPER DIVERGENCE OVER CENTRAL/ERN NC IN THE RIGHT ENTRANCE
REGION OF THE SOUTHERLY JET TO OUR NNW. AFTER MUCH COORDINATION AND
DISCUSSION... WILL NOT GO WITH A FLASH FLOOD WATCH AS YET... AS
WIDESPREAD HEAVY RAIN HAS YET TO MATERIALIZE IN THE ERN
PIEDMONT/SANDHILLS/COASTAL PLAIN WHERE THE MORE SANDY SOIL AND
FLATTER TERRAIN RESULTS IN SLOWER RUNOFF... BUT URBAN AREAS WILL
REMAIN VULNERABLE TO SOME FLOODING. WE WILL CONTINUE TO RE-EVALUATE
AND CONSIDER THIS RISK AS WE HEAD THROUGH THE WEEKEND. WILL HAVE A
GOOD CHANCE OF SHOWERS/STORMS WEST SATURDAY AFTERNOON/NIGHT WITH
LIKELY POPS ALONG/EAST OF THE AFOREMENTIONED LINE COVERING THE
CENTRAL/ERN CWA. DEEP LAYER SHEAR IS NOT TREMENDOUS BUT DOES IMPROVE
FURTHER TO 25-35 KTS... ALTHOUGH MODEL MLCAPE VALUES ONLY PEAK AT
800-1500 J/KG SATURDAY AFTERNOON ALONG/EAST OF HIGHWAY 1...
SUGGESTING PERHAPS A MORE MOIST-ADIABATIC PROFILE THAN WE`VE SEEN
LATELY. POTENTIALLY WEAKER UPDRAFTS ESPECIALLY ALOFT COULD LOWER THE
RISK OF SEVERE STORMS... BUT AGAIN THE DEEP WARM LAYER (LCL TO
FREEZING DEPTH NEAR 4 KM) AND PW NEAR 2 INCHES (WHICH IS NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL) SUPPORT A HEAVY RAIN THREAT WITH
WARM RAIN PROCESSES DOMINATING. HIGHS 87-91. LOWS 68-72. -GIH
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...
THE WELL-ADVERTISED DEVELOPING TROUGH ALOFT WILL HAVE BECOME
STRONGLY AMPLIFIED AND ESTABLISHED OVER THE TN VALLEY THIS
PERIOD...BETWEEN A PAIR OF ANOMALOUSLY STRONG RIDGES OVER WESTERN N.
AMERICA AND THE WESTERN N. ATLANTIC. WHILE LOW LEVEL CONVERGENCE IN
ASSOCIATION WITH A LEE TROUGH/WEAK FRONT WILL HAVE DIMINISHED FROM
PREVIOUS DAYS...THE PATTERN OF PERTURBED SW TO SSW DEEP LAYER FLOW
WILL DRIVE NUMEROUS TO WIDESPREAD SHOWERS/STORMS...AMIDST A DEEP
MOIST AXIS CHARACTERIZED BY PRECIPITABLE WATER VALUES AROUND TWO
INCHES...SUNDAY AND LIKELY THROUGHOUT SUNDAY NIGHT. DEEP LAYER SHEAR
ON THE ORDER OF 25-30 KTS...TO PERHAPS 35 KTS OVER THE NW
PIEDMONT...WILL SUPPORT PRIMARILY MULTI-CELL BANDS CAPABLE OF
PRODUCING WET MICROBURSTS...AND TO A GREATER EXTENT LOCALIZED
FLOODING OWING THE ANOMALOUSLY HIGH PW/S. HIGHS GENERALLY IN THE MID
80S...AND LOWER 70S FOR LOWS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 PM FRIDAY...
CONTINUED...IF NOT INCREASINGLY...WET. THE LARGE SCALE
RIDGE/TROUGH/RIDGE CONFIGURATION ACROSS NOAM WILL GRADUALLY
RETROGRESS...WITH THE TROUGH DRIFTING WESTWARD INTO THE MS
VALLEY...THROUGH MID-LATE WEEK. THE PRESENCE AND PERSISTENCE OF THE
TROUGH WILL KEEP MUCH OF THE EASTERN US...INCLUDING CENTRAL NC...IN
A PATTERN OF PERTURBED AND DEEPLY MOIST SW TO SSW FLOW ALOFT -
FAVORABLE FOR ABOVE AVERAGE PRECIPITATION CHANCES...PARTICULARLY
THROUGH WEDNESDAY. THE PROLONGED STORMY PERIOD WILL FAVOR AN
INCREASING RISK OF FLOODING WITH EACH DAY THAT PASSES...WITH
OTHERWISE AN OCCASIONAL PRECIPITATION-LOADED WET MICROBURST FROM
LOOSELY ORGANIZED MULTI-CELL STORM MODES DRIVEN BY GENERALLY 20-25
KTS OF MID LEVEL FLOW. ASIDE FROM THE 00Z/28TH ECMWF...THE CONSENSUS
OF MEDIUM RANGE GUIDANCE...INCLUDING THE 00Z ECMWF ENSEMBLE
MEAN...INDICATES THE PATTERN RETROGRESSION WILL ALLOW THE WESTERN
ATLANTIC SUB-TROPICAL RIDGING TO EXPAND WESTWARD SUFFICIENTLY TO
LESSEN PRECIPITATION CHANCES/COVERAGE - FROM NUMEROUS/WIDESPREAD TO
SCATTERED - OVER EASTERN NC...INCLUDING THE RAH COASTAL PLAIN...BY
MID TO LATE WEEK. HIGHS MOSTLY IN THE MIDDLE 80S...WITH LOWS 70 TO
75.
&&
.AVIATION /00Z FRIDAY THROUGH WEDNESDAY/...
AS OF 745 PM FRIDAY...
A LINE OF SHOWERS AND THUNDERSTORMS WITH WIND GUSTS UP TO 30 OR 40
MPH ON AVERAGE WILL CONTINUE TO MOVE EAST AND AFFECT KRWI AND KFAY
THROUGH AROUND 03Z...AFTER WHICH TIME ADDITIONAL SCATTERED SHOWERS
AND ISOLATED WEAKER STORMS (THAN PREVIOUS ONES) WILL REDEVELOP AND
SPREAD NORTHEASTWARD ACROSS CENTRAL NC BETWEEN 03-07Z...IN
ASSOCIATION WITH A LIFT-INDUCING MID LEVEL IMPULSE. -MWS
OTHERWISE...BASED ON THE PERSISTENCE OF THE CURRENT PATTERN...AREAS
OF IFR/LIFR STRATUS ARE POSSIBLE AFTER 07Z TONIGHT AT RDU/RWI/FAY...
BUT ONCE AGAIN THE MODELS ARE PRESENTING CONFLICTING GUIDANCE
REGARDING THIS THREAT...SO CONFIDENCE IN OCCURRENCE OF A PREDOMINANT
IFR/LIFR CIG IS LOW. ANY SUCH STRATUS WOULD LIFT BY 14Z SATURDAY
MORNING...AND VFR CONDITIONS WOULD THEN HOLD THROUGH 18Z.
LOOKING BEYOND 00Z SUNDAY...SHOWERS/STORMS AND ATTENDANT MVFR OR
IFR CONDITIONS ARE EXPECTED TO BECOME MORE NUMEROUS SATURDAY
AFTERNOON INTO THE NIGHT... SO EXPECT INCREASINGLY POTENTIAL FOR
ADVERSE AVIATION CONDITIONS... ESPECIALLY AT RDU/RWI/FAY. WITH
MINIMAL CHANGE IN THE OVERALL PATTERN OVER THE CONUS... THE RISK FOR
DAILY NUMEROUS SUB-VFR SHOWERS AND STORMS (PRIMARILY FROM MID
AFTERNOON THROUGH MIDNIGHT) AND SHALLOW EARLY-MORNING IFR STRATUS IS
EXPECTED TO PERSIST INTO THE MIDDLE OF NEXT WEEK. -GIH
&&
.EQUIPMENT...
KRAX WSR-88D IS BACK IN OPERATIONAL SERVICE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...MWS/HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
713 PM EDT FRI JUN 28 2013
.SYNOPSIS...
THE POTENTIAL FOR HEAVY RAINFALL WILL INCREASE THROUGH THE WEEKEND
AS TROPICAL MOISTURE STREAMS INTO THE CAROLINAS. THE UNSETTLED
WEATHER WILL CONTINUE INTO MUCH OF NEXT WEEK AS AN UNUSUALLY DEEP
UPPER LEVEL LOW SITS WEST OF THE REGION...AND INTERACTS WITH BERMUDA
HIGH PRESSURE OFFSHORE.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 730 PM FRIDAY...A ZONE OF MID-LEVEL DRY AIR BETWEEN TWO
SHORTWAVES HAS BROUGHT A TEMPORARY LULL IN CONVECTIVE ACTIVITY
ACROSS THE EASTERN CAROLINAS TODAY. THIS LULL SHOULD COME TO AN END
OVER THE NEXT SEVERAL HOURS AS A MODEST SHORTWAVE CURRENTLY
EXTENDING FROM WESTERN NC INTO CENTRAL GEORGIA AND ALABAMA PUSHES
EAST INTO THE CAROLINAS.
RADAR SHOWS A SQUALL LINE EXTENDING ACROSS NORTH-CENTRAL NORTH
CAROLINA FROM THE VA BORDER SOUTHWARD TO NEAR SOUTHERN PINES. THIS
ACTIVITY IS PROGRESSING MAINLY EAST AND SHOULD MOVE JUST NORTH OF
LUMBERTON BETWEEN 8-9 PM...BUT COULD SCRAPE THE NORTHERN HALVES OF
BLADEN AND PENDER COUNTIES BETWEEN 9-11 PM. WHAT I AM MORE CONCERNED
ABOUT IS NEW CONVECTIVE ACTIVITY DEVELOPING ACROSS WESTERN SOUTH
CAROLINA ASSOCIATED WITH THE MAIN SHORTWAVE ALOFT. LIKE LAST NIGHT
THE HOURLY HRRR RUNS ARE NOT INITIALIZING PERFECTLY BUT MOST PAINT A
STORY OF THUNDERSTORM ACTIVITY INCREASING ACROSS THE PEE DEE REGION
OF EASTERN SOUTH CAROLINA LATE THIS EVENING...SPREADING TO THE COAST
OF BOTH SOUTH AND NORTH CAROLINA AFTER MIDNIGHT. ALTHOUGH MY TIMING
ON THIS CONVECTION IS DIFFERENT FROM THE PREVIOUS FORECAST...MY
12-HOUR POPS ARE NOT SUBSTANTIALLY DIFFERENT: 50-70 PERCENT...
HIGHEST NORTH OF A LINE FROM LAKE CITY TO CONWAY TO WHITEVILLE AND
WILMINGTON.
CONFIDENCE THAT WE WILL HAVE CONVECTIVE ACTIVITY OVERNIGHT IS
BOLSTERED BY NOTING HOW LARGE FORECAST CAPE VALUES ARE ON MODEL
SOUNDINGS. EVEN ACCOUNTING FOR A STABLE SURFACE BOUNDARY LAYER...
LIFTING A PARCEL FROM 925 MB LATE THIS EVENING OVER FLORENCE ON A
RECENT RUC MODEL RUC SHOWS CAPE OVER 2000 J/KG WITH NO CONVECTIVE
INHIBITION. PRECIPITABLE WATER...WHICH HAD FALLEN TO 1.6 TO 1.7
INCHES THIS AFTERNOON...SHOULD RISE BACK TO 2+ INCHES AS THE 850 AND
700 MB LAYER MOISTENS OVERNIGHT.
NO CHANGES HAVE BEEN MADE TO LOW TEMPERATURE FORECASTS...STILL
EXPECTED TO RANGE FROM 73-75 INLAND WITH UPPER 70S NEAR THE COAST.
THIS IS NOT COINCIDENTALLY VERY NEAR OUR CURRENTLY OBSERVED
DEWPOINTS ACROSS THE AREA.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...JUNE IS GOING TO FINISH PRETTY MUCH HOW IT HAS
BEEN ALL MONTH...WARM...HUMID...AND UNSETTLED. IN FACT...THE WEEKEND
HAS THE POTENTIAL TO BE EVEN WETTER THAN MOST OF THE DAYS THIS
MONTH...AND THE LOCAL CLIMATE STATIONS WILL APPROACH OR EXCEED ALL
TIME-MONTHLY RAINFALL RECORDS FOR JUNE BEFORE THE PERIOD COMES TO AN
END.
HIGHLY ANOMALOUS PATTERN AT 500MB PERSISTS AND AMPLIFIES THROUGH THE
WEEKEND WITH A STRONG RIDGE CENTERED ACROSS THE SOUTHWEST AND A
DEEPENING TROUGH DROPPING ACROSS THE OH VLY. THIS AMPLIFICATION
FORCES A STALL IN THE ATMOSPHERIC RIVER...AND DRIVES THE TROUGH BACK
TO THE SW...CREATING HEIGHT ANOMALIES OF -3 SD`S ACROSS THE TN VLY.
WITH THE DEEPENING TROUGH AXIS DISPLACED WEST OF THE
CAROLINAS...THIS KEEPS DEEP SW FLOW ONGOING IN THIS AREA...AND PWATS
RISE TO 2 INCHES OR MORE...AROUND 2 SD`S ABOVE NORMAL. 5H TROUGH TO
THE WEST WITH DEEP MOISTURE PLUME ACROSS THE CAROLINAS CREATES AN
ENVIRONMENT FAVORABLE FOR HEAVY RAIN...BUT OTHER PARAMETERS AS WELL
SUGGEST A VERY WET PERIOD AHEAD FOR THE WKND.
700MB TROUGH WEST OF THE AREA SHARPENS...KEEPING THE GOMEX WIDE
OPEN AND HELPING TO ADVECT TREMENDOUS THETA-E RIDGING FROM 925MB
THROUGH 700MB. 850MB MOISTURE TRANSPORT VECTORS LENGTHEN AND POINT
RIGHT INTO THE COASTAL CAROLINAS...WITH STREAMLINES SUGGESTING
MORE AND MORE OF THAT GULF TAP. ADDITIONALLY...AS THE TROUGH
SHARPENS...ESPECIALLY SUNDAY...200MB JETTING INCREASES WITH THE
SOUTHEAST ALIGNING BENEATH THE RRQ WHICH WILL COMBINE WITH WEAK
500MB SHORTWAVES TO HELP DRIVE LIFT OVER THE AREA. WHILE
INSTABILITY WILL NOT BE EXTREME...MLCAPE OF 800-1200 J/KG WITH
LI`S AROUND -4...AND WARM CLOUD PROCESSES WILL DOMINATE THANKS TO
13000-14000 FT OF WARM CLOUD DEPTH...ENOUGH LIFT WILL CREATE THE
POTENTIAL FOR ISOLATED WET MICROBURSTS EVEN THOUGH HEAVY RAIN WILL
BE THE PREDOMINANT THREAT BOTH DAYS.
SO THE INGREDIENTS ARE IN PLACE TO SUPPORT AN EXTENDED WET
PERIOD...AND WPC HAS 1-3" OF QPF ACROSS THE AREA...ALTHOUGH ISOLATED
MUCH HIGHER TOTALS ARE LIKELY. THIS WILL OCCUR ACROSS A REGION THAT
HAS SEEN 150-300% OF NORMAL RAINFALL THE PAST TWO WEEKS...SO ANY
HEAVY RAINFALL WILL LIKELY CAUSE SOME FLOODING CONCERNS. AFTER
COLLABORATION WITH SURROUNDING OFFICES...HAVE CHOSEN TO HOLD OFF ON
ANY AREAL FLOOD WATCHES SINCE CONVECTION WILL BE SCATTERED TO
WIDESPREAD...MEANING CWA-BASIN RAINFALL WILL BE HIGHLY VARIABLE.
NEVERTHELESS...WILL NEED TO MONITOR FOR POTENTIAL FLOOD WATCHES AS
THE SYNOPTIC SETUP DEVELOPS IN TIME.
ONE FINAL NOTE ABOUT THE UPCOMING RAINFALL. THE CLIMATE STATIONS OF
FLORENCE, SC AND WILMINGTON, NC ARE BOTH APPROACHING MONTHLY RECORDS
FOR JUNE...AND WOULD NOT BE SURPRISED IF THESE RECORDS ARE ECLIPSED
BEFORE JULY BEGINS:
AT WILMINGTON...10.34" HAS FALLEN SO FAR...2.53" BEHIND THE JUNE
RECORD OF 12.87" (1962).
AT FLORENCE...7.89" HAS FALLEN THIS MONTH...1.30" BEHIND THE RECORD
OF 9.29" (1961).
SW WINDS THROUGH THE PERIOD WILL KEEP THE AIRMASS WARM...BUT TEMPS
WILL LIKELY REMAIN JUST BELOW NORMAL THANKS TO THE WIDESPREAD CLOUD
COVER AND CONVECTION. EXPECT HIGHS IN THE MID/UPR 80S BOTH
AFTNS...BUT WITH SIGNIFICANT VARIABILITY WITHIN SHOWERS/TSTMS. LOWS
AT NIGHT WILL FALL TO 70 OR A FEW DEGREES ABOVE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...HIGHLY AMPLIFIED MID LEVEL PATTERN WILL
CONTINUE THROUGH MOST OF THE EXTENDED PERIOD WHICH MEANS A
CONTINUATION OF THE UNSETTLED CONDITIONS. WPC HAS LIKELY POPS FOR
MONDAY THROUGH WEDNESDAY DURING THE DAYTIME HOURS WITH LOWER
VALUES FOR THE NIGHTTIME HOURS. THIS CERTAINLY SEEMS REASONABLE AS
THE RIVER OF MOISTURE WILL CONTINUE FROM THE SOUTH/SOUTHWEST.
THERE ARE INDICATIONS THE PATTERN WILL BREAK DOWN LATE IN THE
PATTERN WITH SLIGHT RIDGING BUILDING IN WHICH WARRANTS A SLIGHT
DOWNTURN IN POPS. WITH THE PATTERN CHANGING LITTLE...EXPECT
TEMPERATURES TO REMAIN STABLE WITH HIGHS A LITTLE BELOW NORMAL
WITH ALL THE MOISTURE AND OVERNIGHT LOWS A LITTLE ABOVE FOR THE
SAME REASON.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...HRRR MODEL APPEARS TOO PESSIMISTIC WITH THE EARLY
CONVECTION. LACK OF MODERATE CU INDICATES WE ARE STILL MILDLY
CAPPED...HOWEVER THAT WILL CHANGE AFTER 03Z AS DEEP MOISTURE INVADES
FROM THE WEST. LBT COULD GET BRUSHED EARLIER THAN THAT...WITH A
DECENT COMPLEX OF CONVECTION TO THE NORTH. TOWARD MORNING...DEEP
MOISTURE IN PLACE AT ALL TERMINALS...WITH SCATTERED TO NUMEROUS
CONVECTION EXPECTED...WITH ISOLATED THUNDER. CEILINGS WILL LOWER TO
MVFR WITH BRIEF IFR VISIBILITIES IN THE HEAVIER SHOWERS.
SATURDAY...EXPECT INTERMITTENT CONVECTION MOST OF THE DAY. SOME
DRYING ALOFT IS INDICATED AT THE INLAND TERMINALS...HOWEVER THIS MAY
JUST ALLOW MORE HEATING FOR POSSIBLE AFTERNOON THUNDERSTORMS. AGAIN
MVFR CEILINGS ARE EXPECTED THROUGHOUT MOST OF THE DAY.
EXTENDED OUTLOOK...ISOLATED/SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM FRIDAY...BERMUDA HIGH PRESSURE WELL OFFSHORE IS HAVING
LIMITED SUCCESS PUSHING WESTWARD INTO WHAT HAS BECOME (FOR THE
SEASON) A VERY STRONG TROUGH OF LOW PRESSURE INLAND. BAROMETRIC
PRESSURES ARE SURPRISINGLY LOW FOR LATE JUNE...29.67 INCHES HERE IN
WILMINGTON AS I TYPE. THE PATTERN WILL NOT CHANGE OVERNIGHT WITH A
HEALTHY FLOW OF SOUTHWEST WINDS 20-25 KNOTS EXPECTED TO CONTINUE.
THIS WIND HAS BUILT SEAS TO 7 FT AT THE FRYING PAN SHOALS BUOY...6
FT AT THE NEW WILMINGTON "HARBOR" BUOY JUST SOUTH OF THE MOUTH OF
THE CAPE FEAR RIVER...AND 5 FT AT THE OCEAN CREST PIER WAVE GAUGE.
THE BIGGEST CHANGE TO THE FORECAST OVERNIGHT WAS TO INCREASE
NEARSHORE WAVE HEIGHTS BASED PRIMARILY ON THE REPORT FROM THE OCEAN
CREST PIER REPORT.
SHOWERS JUST INLAND FROM GEORGETOWN DEVELOPED A COUPLE HOURS AGO
ALONG THE SEABREEZE...AND THESE SHOULD LARGELY DISSIPATE OVER THE
NEXT HOUR. AN UPPER LEVEL DISTURBANCE MOVING ACROSS THE WESTERN
CAROLINAS WILL APPROACH THE COASTAL WATERS LATE TONIGHT BRINGING
SCATTERED SHOWERS AND THUNDERSTORMS...MOST NUMEROUS NORTH OF CAPE
FEAR.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...EXTENDED SMALL CRAFT ADVISORY IN PLACE FOR
MUCH OF THE PERIOD...AND THERE IS A GOOD CHANCE IT WILL BE EXTENDED
IN TIME INTO NEXT WEEK. LARGE BERMUDA TYPE HIGH PRESSURE
OFFSHORE...AND AREA OF LOW PRESSURE STALLED INLAND...WILL KEEP A
PINCHED GRADIENT OVER THE WATERS. THIS DRIVES SW WINDS UP TO 20-25
KTS SATURDAY...AND ONLY SLIGHTLY WEAKER ON SUNDAY. SEAS WILL BE
DRIVEN PRIMARILY BY THESE WINDS...AND 4-7 FT WAVE HEIGHTS ARE
EXPECTED THROUGH THE PERIOD. ADDITIONALLY...SCATTERED TO
WIDESPREAD TSTMS BOTH DAYS WILL CREATE HEAVY RAINFALL...CAUSING
SEVERELY RESTRICTED VISIBILITY AT TIMES.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...STEADY STATE CONDITIONS FOR THE COASTAL
COMMUNITY THROUGH THE PERIOD WITH SOUTHERLY WINDS OF 15-20 KNOTS
PROBABLY CLOSER TO THE LOWER END OF THE RANGE. PATTERN WEAKENS
EVER SO SLIGHTLY WEDNESDAY WHICH TRANSLATES TO SLIGHTLY LOWER WIND
SPEEDS. WAVEWATCH GUIDANCE SHOWS 3-5 FEET MONDAY AND TUESDAY SO A
SCEC HEADLINE IS POSSIBLE. SIGNIFICANT SEAS DROP TO 2-4 FEET
WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EDT SUNDAY FOR
AMZ250-252-254- 256.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...SHK
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
308 PM EDT THU JUN 27 2013
.SYNOPSIS...
A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW
PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1045 AM THURSDAY...
MORNING STRATUS IS MIXING OUT..THOUGH WITH VARYING AMOUNTS OF
CONVECTIVE DEBRIS CLOUDS ADVECTING EAST ACROSS THE AREA. CLOUD
COVER MAY PERIODICALLY HINDER INSOLATION IN SOME AREAS...BUT
ULTIMATELY EXPECT HIGHS WILL REACH FORECAST VALUES OF MID 80S WEST
TO NEAR 90 IN THE SOUTHEAST. OF GREATER CONCERN IS THE APPROACHING
UPPER-LEVEL TROUGH AND REMNANT CONVECTIVE VORTICITY JUST WEST OF THE
MOUNTAINS. THE TROUGH AXIS WILL CROSS CENTRAL NC DURING PEAK
HEATING TODAY...INTERACTING WITH A MODERATELY UNSTABLE AIRMASS
(MLCAPE REACHING 1500-2000 J/KG) CHARACTERIZED BY DEWPOINTS IN THE
UPPER 60S AND LOWER 70S...AS WELL AS PW OVER 1.75". FURTHER AIDING
INSTABILITY WILL BE A POSSIBLE ELEVATED MIXED LAYER...EVIDENT ON THE
12Z KGSO RAOB. THE 850MB TEMP OF 21C LOOKS A BIT ANOMALOUS
REGIONALLY...BUT THERE DOES APPEAR TO BE A STREAM OF WARMER
925-850MB ROUNDING THE BASE OF THE MEAN TROUGH AXIS OVER THE TN/OH
VALLEY...SO THE POSSIBILITY OF A MODIFIED EML IS NOT DISCOUNTED. IN
FACT...A 14Z AIRCRAFT SOUNDING AT KRDU HAS THE SAME THERMAL
CHARACTER. 0-6KM EFFECTIVE SHEAR IS NOT PARTICULARLY STRONG THIS
MORNING...BUT SHOULD INCREASE TO 20-30KT AS MID-LEVEL WINDS INCREASE
AHEAD OF THE TROUGH. RAP SOUNDING EVEN SHOW A MODEST INCREASE IN
SOUTHERLY LOW-LEVEL FLOW...WITH 0-1KM SHEAR APPROACHING 30KT AT KFAY
BY 21-22Z. WHILE THE DETAILS OF HOW CONVECTION WILL EVOLVE ARE
STILL A LITTLE UNCERTAIN...EXPECT DEVELOPMENT IN THE VICINITY OF THE
LEE TROUGH OVER THE FOOTHILLS AND WESTERN PIEDMONT DURING THE NEXT
FEW HOURS...WITH CLUSTERS OF CONVECTION GROWING UPSCALE AS THEY
MOVES EASTWARD WITH THE UPPER TROUGH AND COLD POOL LATE THIS
AFTERNOON AND EVENING. THE ENSEMBLE OF HI-RES MODELS SEEM TO FOCUS
ON THE 19Z TO 01Z TIME FRAME...WITH BETTER SEVERE POTENTIAL EAST OF
HWY 1. MAIN THREATS WILL BE DAMAGING WINDS AND LARGE HAIL. -BLS
ONCE CONVECTION CLEARS THE AREA...CONDITIONS SHOULD BE QUIET
OVERNIGHT...WITH LOWS IN THE UPPER 60S TO LOWER 70S.
FRIDAY/FRIDAY NIGHT TO BE POSTED SHORTLY.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM THURSDAY...
AN ANOMALOUSLY AMPLIFIED PATTERN WILL PREVAIL ACROSS THE CONUS
THROUGH THE WEEKEND...CHARACTERIZED BY A DEEP UPPER LEVEL RIDGE OVER
THE ROCKIES/INTERMOUNTAIN WEST AND DEEP TROUGHING EAST OF THE
MISSISSIPPI...WITH A PERSISTENT UPPER LEVEL LOW CENTERED IN VICINITY
OF THE LOWER GREAT LAKES AND OH VALLEY. ACROSS THE CAROLINAS AND
MID-ATLANTIC...EXPECT ATYPICALLY STRONG SOUTHWEST FLOW ALOFT WITH
NUMEROUS SMALL AMPLITUDE SHORTWAVES CROSSING THE REGION THROUGHOUT
THE PERIOD IN THE PRESENCE OF A SEASONABLY MOIST AIRMASS. AS A
RESULT...EXPECT ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS
AND SLIGHTLY BELOW NORMAL HIGH TEMPS IN THE MID 80S...DEPENDING ON
CLOUD COVER AND CONVECTION. THE EXACT COVERAGE AND PERSISTENCE OF
CONVECTION WILL HIGHLY DEPEND ON THE EVOLUTION OF SMALL AMPLITUDE
DISTURBANCES IN SW FLOW ALOFT AND THE TIMING OF THESE DISTURBANCES
IN RELATION TO THE DIURNAL HEATING CYCLE. FURTHERMORE...THE DEGREE
OF DIURNAL DESTABILIZATION IS DIFFICULT TO ASCERTAIN GIVEN INCREASED
CLOUD COVER AND AN ABOVE NORMAL CHANCE FOR NOCTURNAL OR EARLY
MORNING CONVECTION...THOUGH ONE WOULD EXPECT AT LEAST SOME CLOUD
BREAKS AND AREAS OF RELATIVELY STRONGER INSOLATION DURING PEAK
HEATING. EITHER WAY...SLIGHTLY STEEPER MID-LEVEL LAPSE RATES /COOLER
TEMPS ALOFT/ IN ASSOCIATION WITH THE UNUSUALLY AMPLIFIED UPPER LEVEL
TROUGH OVER THE REGION WILL AT LEAST SOMEWHAT COMPENSATE FOR
DECREASED INSOLATION. GIVEN DEEP-LAYER (0-6 KM) SHEAR LIKELY IN THE
35-45 KT RANGE...ORGANIZED CONVECTION WILL CERTAINLY BE POSSIBLE...
INCLUDING SUPERCELLS...THOUGH THE TYPE/EXTENT OF ANY SEVERE THREAT
CANNOT BE PRECISELY IDENTIFIED AT THIS TIME. IN ADDITION TO A
POTENTIAL FOR SEVERE THUNDERSTORMS...ISOLATED FLASH FLOODING WILL
ALSO BE POSSIBLE GIVEN RECENT HEAVY RAINFALL AND ABOVE NORMAL
CHANCES FOR CONVECTION THROUGH THE WEEKEND. -VINCENT
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...
TO BE POSTED SHORTLY. -VINCENT
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 140 PM THURSDAY...
SKIES ARE VARIABLY CLOUDY WITH VFR CONDITIONS ACROSS CENTRAL NC.N
AN APPROACHING UPPER LEVEL TROUGH AND AND AN UNSTABLE AIRMASS WILL
LEAD TO SCATTERED TO NUMEROUS SHOWERS AND STORMS THIS AFTERNOON AND
EVENING. WHILE CONFIDENCE IN IS/WHEN STORMS WILL IMPACT INDIVIDUAL
TERMINALS IS STILL LOW...PROBABILITIES WILL BE HIGHEST FROM KFAY TO
KRWI WHERE HEATING AND MOISTURE AREA GREATEST TODAY. THE CHANCE OF
OF STORMS SHOULD DECREASE SIGNIFICANTLY BY 00-03Z FROM WEST TO EAST.
QUIET CONDITIONS WILL PREVAIL OVERNIGHT...WITH AT LEAST A CHANCE OF
PATCHY STRATUS ACROSS PORTIONS OF EASTERN NC BASED ON FORECAST
SOUNDINGS.
OUTLOOK...
UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE WEEKEND AND
INTO NEXT WEEK AS A DEEP UPPER LEVEL TROUGH SETS UP ACROSS THE
EASTERN US. PERIODS OF SHOWERS AND STORMS CAN BE EXPECTED EACH
AFTERNOON...WITH EARLY MORNING STRATUS OR FOG.
&&
.EQUIPMENT...
KRAX WSR-88D WILL BE DOWN FOR MUCH-NEEDED MAINTENANCE TODAY. KRAX
HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE
NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS
WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE. WE APOLOGIZE FOR THE
INCONVENIENCE. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...CBL/BLS
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
140 PM EDT THU JUN 27 2013
.SYNOPSIS...
A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW
PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM THURSDAY...
MORNING STRATUS IS MIXING OUT..THOUGH WITH VARYING AMOUNTS OF
CONVECTIVE DEBRIS CLOUDS ADVECTING EAST ACROSS THE AREA. CLOUD
COVER MAY PERIODICALLY HINDER INSOLATION IN SOME AREAS...BUT
ULTIMATELY EXPECT HIGHS WILL REACH FORECAST VALUES OF MID 80S WEST
TO NEAR 90 IN THE SOUTHEAST. OF GREATER CONCERN IS THE APPROACHING
UPPER-LEVEL TROUGH AND REMNANT CONVECTIVE VORTICITY JUST WEST OF THE
MOUNTAINS. THE TROUGH AXIS WILL CROSS CENTRAL NC DURING PEAK
HEATING TODAY...INTERACTING WITH A MODERATELY UNSTABLE AIRMASS
(MLCAPE REACHING 1500-2000 J/KG) CHARACTERIZED BY DEWPOINTS IN THE
UPPER 60S AND LOWER 70S...AS WELL AS PW OVER 1.75". FURTHER AIDING
INSTABILITY WILL BE A POSSIBLE ELEVATED MIXED LAYER...EVIDENT ON THE
12Z KGSO RAOB. THE 850MB TEMP OF 21C LOOKS A BIT ANOMALOUS
REGIONALLY...BUT THERE DOES APPEAR TO BE A STREAM OF WARMER
925-850MB ROUNDING THE BASE OF THE MEAN TROUGH AXIS OVER THE TN/OH
VALLEY...SO THE POSSIBILITY OF A MODIFIED EML IS NOT DISCOUNTED. IN
FACT...A 14Z AIRCRAFT SOUNDING AT KRDU HAS THE SAME THERMAL
CHARACTER. 0-6KM EFFECTIVE SHEAR IS NOT PARTICULARLY STRONG THIS
MORNING...BUT SHOULD INCREASE TO 20-30KT AS MID-LEVEL WINDS INCREASE
AHEAD OF THE TROUGH. RAP SOUNDING EVEN SHOW A MODEST INCREASE IN
SOUTHERLY LOW-LEVEL FLOW...WITH 0-1KM SHEAR APPROACHING 30KT AT KFAY
BY 21-22Z. WHILE THE DETAILS OF HOW CONVECTION WILL EVOLVE ARE
STILL A LITTLE UNCERTAIN...EXPECT DEVELOPMENT IN THE VICINITY OF THE
LEE TROUGH OVER THE FOOTHILLS AND WESTERN PIEDMONT DURING THE NEXT
FEW HOURS...WITH CLUSTERS OF CONVECTION GROWING UPSCALE AS THEY
MOVES EASTWARD WITH THE UPPER TROUGH AND COLD POOL LATE THIS
AFTERNOON AND EVENING. THE ENSEMBLE OF HI-RES MODELS SEEM TO FOCUS
ON THE 19Z TO 01Z TIME FRAME...WITH BETTER SEVERE POTENTIAL EAST OF
HWY 1. MAIN THREATS WILL BE DAMAGING WINDS AND LARGE HAIL. -BLS
ONCE CONVECTION CLEARS THE AREA... CONDITIONS SHOULD BE QUIET
OVERNIGHT...WITH LOWS IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 300 AM THURSDAY...
MORE OF THE SAME IS EXPECTED FOR FRIDAY AS AFTERNOON/EVENING
CONVECTION WILL DEVELOP ONCE AGAIN ACROSS THE REGION. HOWEVER...
COVERAGE MAY BE SLIGHTLY LESS (WHEN COMPARED TO THURSDAY) AS CENTRAL
NC WILL BE IN-BETWEEN TWO UPPER LEVEL TROUGHS AND THEREFORE DYNAMIC
FORCING WILL BE WEAKER. NEVERTHELESS...AT THE SURFACE A LEE TROUGH
WILL PROVIDE SUFFICIENT LOW LEVEL CONVERGENCE FOR THE DEVELOPMENT OF
SCATTERED THUNDERSTORMS ACROSS THE FORECAST AREA AS A VERY MOIST AND
UNSTABLE AIRMASS WILL STILL IN PLACE AND WEAK DISTURBANCES WILL
LIKELY MOVE THROUGH THE REGION IN THE DEEP WESTERLY/SOUTHWESTERLY
FLOW ALOFT. AS HAS BEEN THE CASE...THE STRONGEST STORMS WILL BE
CAPABLE OF PRODUCING LOCALIZED FLOODING...SOME DAMAGING WIND GUSTS
AND POSSIBLY SOME SMALL HAIL. WITH SLIGHTLY LESS IN THE WAY OF
CONVECTIVE COVERAGE...HIGHS MAY BE A COUPLE OF DEGREES HIGHER THAN
THURSDAY... GENERALLY WITHIN A DEGREE OR TWO ON EITHER SIDE OF 90.
OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...
AN UNUSUALLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST THROUGH MUCH
OF THE LONG TERM PERIOD AS A RIDGE BUILDS OVER THE WESTERN HALF OF
THE CONUS (EXTENDING UP INTO CANADA)...WITH A DEEP TROUGH OVER THE
EASTERN HALF. THIS TROUGH WILL BE CENTERED OVER THE OHIO VALLEY
EARLY IN THE PERIOD...BEFORE RETROGRADING SLIGHTLY THROUGH EARLY/MID
NEXT WEEK. REGARDLESS...THIS PATTERN WILL LEAVE CENTRAL NC WITHIN A
VERY MOIST AIR MASS AS DEEP SOUTHWESTERLY FLOW PERSISTS. AS A
RESULT...UNSETTLED WEATHER WILL CONTINUE THROUGH THE ENTIRE LONG
TERM PERIOD (IF NOT LONGER) ACROSS CENTRAL NC...WITH ABOVE NORMAL
CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED
EACH DAY. A COUPLE OF NOTES ABOUT PRECIP CHANCES...ON SATURDAY SOME
SLIGHTLY DRIER AIR IS PROGGED TO MOVE INTO THE WESTERN PORTIONS OF
THE FORECAST AREA (AS A SURFACE FRONT NUDGES INTO THE REGION) AND
THIS COULD HOLD DOWN PRECIP CHANCES ACROSS THAT PART OF THE FORECAST
AREA. HOWEVER...MOISTURE QUICKLY RETURNS LATE SATURDAY AND THE BRIEF
LULL IN PRECIP SHOULD END. THEN...AS THE UPPER LEVEL TROUGH
RETROGRADES SOME TO BEGIN THE WEEK...THE RIDGE OVER THE WESTERN
ATLANTIC WILL ALSO RETROGRADE...THEREFORE EVENTUALLY EXERTING SOME
MORE INFLUENCE OVER THE REGION BY THE MIDDLE OF THE WEEK. THIS IS
WHEN WE MAY START SEEING A DECREASE IN PRECIP COVERAGE...ESPECIALLY
OVER EASTERN NC.
OTHERWISE...WITH INCREASING FLOW ALOFT...THE SHEAR WILL IMPROVE OVER
THE AREA (ESPECIALLY ACROSS THE NORTH AND WEST THROUGH MONDAY AS THE
AFOREMENTIONED TROUGH IS CLOSEST TO THE REGION) AND THEREFORE WE
SHOULD SEE MORE IN THE WAY OF ORGANIZED CONVECTION OVER THE WEEKEND.
THIS MAY RESULT IN SOME STRONG TO SEVERE STORMS...WITH DAMAGING WIND
GUSTS BEING THE PRIMARY THREAT. HOWEVER...A SIGNIFICANT WEATHER
THREAT WILL LIKELY BE THE INCREASING FLOODING RISK AS THE AREA
REMAINS IN THIS EXTENDED WET PATTERN. DAYTIME HIGHS WILL GENERALLY
BE BELOW NORMAL THROUGH THE PERIOD...WITH MOSTLY MID 80S EXPECTED.
OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 140 PM THURSDAY...
SKIES ARE VARIABLY CLOUDY WITH VFR CONDITIONS ACROSS CENTRAL NC.N
AN APPROACHING UPPER LEVEL TROUGH AND AND AN UNSTABLE AIRMASS WILL
LEAD TO SCATTERED TO NUMEROUS SHOWERS AND STORMS THIS AFTERNOON AND
EVENING. WHILE CONFIDENCE IN IS/WHEN STORMS WILL IMPACT INDIVIDUAL
TERMINALS IS STILL LOW...PROBABILITIES WILL BE HIGHEST FROM KFAY TO
KRWI WHERE HEATING AND MOISTURE AREA GREATEST TODAY. THE CHANCE OF
OF STORMS SHOULD DECREASE SIGNIFICANTLY BY 00-03Z FROM WEST TO EAST.
QUIET CONDITIONS WILL PREVAIL OVERNIGHT...WITH AT LEAST A CHANCE OF
PATCHY STRATUS ACROSS PORTIONS OF EASTERN NC BASED ON FORECAST
SOUNDINGS.
OUTLOOK...
UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE WEEKEND AND
INTO NEXT WEEK AS A DEEP UPPER LEVEL TROUGH SETS UP ACROSS THE
EASTERN US. PERIODS OF SHOWERS AND STORMS CAN BE EXPECTED EACH
AFTERNOON...WITH EARLY MORNING STRATUS OR FOG.
&&
.EQUIPMENT...
KRAX WSR-88D WILL BE DOWN FOR MUCH-NEEDED MAINTENANCE TODAY. KRAX
HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE
NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS
WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE. WE APOLOGIZE FOR THE
INCONVENIENCE. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...CBL/BLS
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1045 AM EDT THU JUN 27 2013
.SYNOPSIS...
A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW
PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM THURSDAY...
MORNING STRATUS IS MIXING OUT..THOUGH WITH VARYING AMOUNTS OF
CONVECTIVE DEBRIS CLOUDS ADVECTING EAST ACROSS THE AREA. CLOUD
COVER MAY PERIODICALLY HINDER INSOLATION IN SOME AREAS...BUT
ULTIMATELY EXPECT HIGHS WILL REACH FORECAST VALUES OF MID 80S WEST
TO NEAR 90 IN THE SOUTHEAST. OF GREATER CONCERN IS THE APPROACHING
UPPER-LEVEL TROUGH AND REMNANT CONVECTIVE VORTICITY JUST WEST OF THE
MOUNTAINS. THE TROUGH AXIS WILL CROSS CENTRAL NC DURING PEAK
HEATING TODAY...INTERACTING WITH A MODERATELY UNSTABLE AIRMASS
(MLCAPE REACHING 1500-2000 J/KG) CHARACTERIZED BY DEWPOINTS IN THE
UPPER 60S AND LOWER 70S...AS WELL AS PW OVER 1.75". FURTHER AIDING
INSTABILITY WILL BE A POSSIBLE ELEVATED MIXED LAYER...EVIDENT ON THE
12Z KGSO RAOB. THE 850MB TEMP OF 21C LOOKS A BIT ANOMALOUS
REGIONALLY...BUT THERE DOES APPEAR TO BE A STREAM OF WARMER
925-850MB ROUNDING THE BASE OF THE MEAN TROUGH AXIS OVER THE TN/OH
VALLEY...SO THE POSSIBILITY OF A MODIFIED EML IS NOT DISCOUNTED. IN
FACT...A 14Z AIRCRAFT SOUNDING AT KRDU HAS THE SAME THERMAL
CHARACTER. 0-6KM EFFECTIVE SHEAR IS NOT PARTICULARLY STRONG THIS
MORNING...BUT SHOULD INCREASE TO 20-30KT AS MID-LEVEL WINDS INCREASE
AHEAD OF THE TROUGH. RAP SOUNDING EVEN SHOW A MODEST INCREASE IN
SOUTHERLY LOW-LEVEL FLOW...WITH 0-1KM SHEAR APPROACHING 30KT AT KFAY
BY 21-22Z. WHILE THE DETAILS OF HOW CONVECTION WILL EVOLVE ARE
STILL A LITTLE UNCERTAIN...EXPECT DEVELOPMENT IN THE VICINITY OF THE
LEE TROUGH OVER THE FOOTHILLS AND WESTERN PIEDMONT DURING THE NEXT
FEW HOURS...WITH CLUSTERS OF CONVECTION GROWING UPSCALE AS THEY
MOVES EASTWARD WITH THE UPPER TROUGH AND COLD POOL LATE THIS
AFTERNOON AND EVENING. THE ENSEMBLE OF HI-RES MODELS SEEM TO FOCUS
ON THE 19Z TO 01Z TIME FRAME...WITH BETTER SEVERE POTENTIAL EAST OF
HWY 1. MAIN THREATS WILL BE DAMAGING WINDS AND LARGE HAIL. -BLS
ONCE CONVECTION CLEARS THE AREA... CONDITIONS SHOULD BE QUIET
OVERNIGHT...WITH LOWS IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 300 AM THURSDAY...
MORE OF THE SAME IS EXPECTED FOR FRIDAY AS AFTERNOON/EVENING
CONVECTION WILL DEVELOP ONCE AGAIN ACROSS THE REGION. HOWEVER...
COVERAGE MAY BE SLIGHTLY LESS (WHEN COMPARED TO THURSDAY) AS CENTRAL
NC WILL BE IN-BETWEEN TWO UPPER LEVEL TROUGHS AND THEREFORE DYNAMIC
FORCING WILL BE WEAKER. NEVERTHELESS...AT THE SURFACE A LEE TROUGH
WILL PROVIDE SUFFICIENT LOW LEVEL CONVERGENCE FOR THE DEVELOPMENT OF
SCATTERED THUNDERSTORMS ACROSS THE FORECAST AREA AS A VERY MOIST AND
UNSTABLE AIRMASS WILL STILL IN PLACE AND WEAK DISTURBANCES WILL
LIKELY MOVE THROUGH THE REGION IN THE DEEP WESTERLY/SOUTHWESTERLY
FLOW ALOFT. AS HAS BEEN THE CASE...THE STRONGEST STORMS WILL BE
CAPABLE OF PRODUCING LOCALIZED FLOODING...SOME DAMAGING WIND GUSTS
AND POSSIBLY SOME SMALL HAIL. WITH SLIGHTLY LESS IN THE WAY OF
CONVECTIVE COVERAGE...HIGHS MAY BE A COUPLE OF DEGREES HIGHER THAN
THURSDAY... GENERALLY WITHIN A DEGREE OR TWO ON EITHER SIDE OF 90.
OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...
AN UNUSUALLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST THROUGH MUCH
OF THE LONG TERM PERIOD AS A RIDGE BUILDS OVER THE WESTERN HALF OF
THE CONUS (EXTENDING UP INTO CANADA)...WITH A DEEP TROUGH OVER THE
EASTERN HALF. THIS TROUGH WILL BE CENTERED OVER THE OHIO VALLEY
EARLY IN THE PERIOD...BEFORE RETROGRADING SLIGHTLY THROUGH EARLY/MID
NEXT WEEK. REGARDLESS...THIS PATTERN WILL LEAVE CENTRAL NC WITHIN A
VERY MOIST AIR MASS AS DEEP SOUTHWESTERLY FLOW PERSISTS. AS A
RESULT...UNSETTLED WEATHER WILL CONTINUE THROUGH THE ENTIRE LONG
TERM PERIOD (IF NOT LONGER) ACROSS CENTRAL NC...WITH ABOVE NORMAL
CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED
EACH DAY. A COUPLE OF NOTES ABOUT PRECIP CHANCES...ON SATURDAY SOME
SLIGHTLY DRIER AIR IS PROGGED TO MOVE INTO THE WESTERN PORTIONS OF
THE FORECAST AREA (AS A SURFACE FRONT NUDGES INTO THE REGION) AND
THIS COULD HOLD DOWN PRECIP CHANCES ACROSS THAT PART OF THE FORECAST
AREA. HOWEVER...MOISTURE QUICKLY RETURNS LATE SATURDAY AND THE BRIEF
LULL IN PRECIP SHOULD END. THEN...AS THE UPPER LEVEL TROUGH
RETROGRADES SOME TO BEGIN THE WEEK...THE RIDGE OVER THE WESTERN
ATLANTIC WILL ALSO RETROGRADE...THEREFORE EVENTUALLY EXERTING SOME
MORE INFLUENCE OVER THE REGION BY THE MIDDLE OF THE WEEK. THIS IS
WHEN WE MAY START SEEING A DECREASE IN PRECIP COVERAGE...ESPECIALLY
OVER EASTERN NC.
OTHERWISE...WITH INCREASING FLOW ALOFT...THE SHEAR WILL IMPROVE OVER
THE AREA (ESPECIALLY ACROSS THE NORTH AND WEST THROUGH MONDAY AS THE
AFOREMENTIONED TROUGH IS CLOSEST TO THE REGION) AND THEREFORE WE
SHOULD SEE MORE IN THE WAY OF ORGANIZED CONVECTION OVER THE WEEKEND.
THIS MAY RESULT IN SOME STRONG TO SEVERE STORMS...WITH DAMAGING WIND
GUSTS BEING THE PRIMARY THREAT. HOWEVER...A SIGNIFICANT WEATHER
THREAT WILL LIKELY BE THE INCREASING FLOODING RISK AS THE AREA
REMAINS IN THIS EXTENDED WET PATTERN. DAYTIME HIGHS WILL GENERALLY
BE BELOW NORMAL THROUGH THE PERIOD...WITH MOSTLY MID 80S EXPECTED.
OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 735 AM THURSDAY...
IFR TO MVFR STRATUS SHOULD LIFT AND SCATTER OUT BY 13 TO 14Z.
THE THREAT FOR ISOLATED TO SCATTERED CONVECTION WILL CONTINUE THIS
MORNING...ESPECIALLY ACROSS THE WESTERN PIEDMONT AS THE MCS COLD
POOL MOVES INTO THE AREA FROM THE WEST.
WITH A WARM MOIST UNSTABLE AIRMASS IN PLACE ACROSS CENTRAL NC
...AN UPPER LEVEL SHORTWAVE WILL MOVE THROUGH THE REGION RESULTING
IN WIDESPREAD SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON.
THERE IS FAIRLY HIGH CONFIDENCE THAT THESE STORMS WILL IMPACT ALL
TERMINALS BEGINNING AROUND MIDDAY IN THE TRIAD BEFORE SPREADING
EASTWARD THROUGH THE EARLY EVENING HOURS.
LOOKING BEYOND 18Z THURSDAY: AN UNSETTLED PATTERN WILL PERSIST ALONG
THE U.S. EAST COAST THROUGH EARLY NEXT WEEK. EXPECT NUMEROUS SHOWERS
AND THUNDERSTORMS EACH AFTERNOON WITH THE THREAT OF SUB-VFR CEILINGS
AND VISIBILITIES DUE TO FOG AND LOW STRATUS EACH MORNING.
&&
.EQUIPMENT...
KRAX WSR-88D WILL BE DOWN FOR MUCH-NEEDED MAINTENANCE TODAY. KRAX
HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE
NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS
WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE. WE APOLOGIZE FOR THE
INCONVENIENCE. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...CBL/BLS
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
926 PM CDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 923 PM CDT FRI JUN 28 2013
A MOSAIC OF AREA RADARS SHOWS MUCH OF THE SHOWER / THUNDERSTORM
ACTIVITY HAS DIMINISHED. CAN NOT COMPLETELY RULE OUT A STRAY
SHOWER OVERNIGHT ACROSS PARTS OF NORTH CENTRAL NORTH DAKOTA AS PER
THE 29.00Z NAM...BUT THOSE CHANCES APPEAR LOW ENOUGH TO OMIT FROM
THE FORECAST AT THIS POINT. MADE ONLY MINOR ADJUSTMENTS TO THE
FORECAST WITH MOST WEATHER ELEMENTS ON TRACK.
UPDATE ISSUED AT 642 PM CDT FRI JUN 28 2013
REGIONAL RADAR MOSAIC EARLY THIS EVENING SHOWS ISOLATED SHOWERS /
THUNDERSTORMS MOVING SOUTH ACROSS PARTS OF EASTERN NORTH DAKOTA.
THE STORMS ARE IN THE AREA WITH THE GREATEST INSTABILITY (1000 J/KG)
WHILE INSTABILITY QUICKLY DECREASES IN CENTRAL AND WESTERN NORTH
DAKOTA. THE LATEST RAP FORECAST SHOWS THE INSTABILITY DECREASING
ACROSS THE FAR EASTERN PART OF THE FORECAST AREA THIS
EVENING...AND LATE AFTERNOON / EARLY EVENING VISIBLE SATELLITE
IMAGERY SHOWS CUMULUS QUICKLY DECREASING. WILL CONTINUE TO CARRY A
SMALL CHANCE OF THUNDERSTORMS IN THE FAR EASTERN PART OF THE
FORECAST AREA FOR ANOTHER COUPLE OF HOURS...BUT THE ACTIVITY
SHOULD WANE THIS EVENING. THE REMAINDER OF THE FORECAST LOOKS
GOOD.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 243 PM CDT FRI JUN 28 2013
MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD WILL BE ISOLATED
THUNDERSTORM CHANCES LATE THIS AFTERNOON INTO THIS EVENING AND AGAIN
SATURDAY AFTERNOON AND EVENING.
CURRENTLY...SURFACE HIGH PRESSURE IS SITUATED OVER THE NORTHERN
ROCKIES AND INTO THE NORTHERN HIGH PLAINS...WITH LOW PRESSURE OVER
THE GREAT LAKES REGION. CUMULUS DEVELOPMENT ACROSS WESTERN AND
CENTRAL NORTH DAKOTA WITH A FEW SHOWERS INDICATED ALONG LAKE
SAKAKAWEA.
BEST CAPE REMAINS ACROSS NORTHERN AND EASTERN NORTH DAKOTA...WHILE
BEST SHEAR IS SITUATED OVER SOUTHWEST NORTH DAKOTA. 28 JUNE 12Z NAM
SOUNDINGS INDICATE A VERY DRY ATMOSPHERE AT BISMARCK AND ESPECIALLY
MINOT AND JAMESTOWN WITH ONLY A VERY THIN MOISTURE LAYER. WESTERN
NORTH DAKOTA APPEARS TO HAVE A BETTER CHANCE OF MORE THAN A SHOWER.
CAPE VALUES ARE LIMITED BUT GOOD SPEED SHEAR EXISTS...WITH 50 KNOTS
OF BULK SHEAR CURRENTLY OVER THE SOUTHWEST. WILL KEEP AN EYE ON THE
RADAR AND LATE AFTERNOON/EVENING POPS WILL BE BASED ON LATEST FRAMES.
ANY CONVECTION THAT WOULD DEVELOP WILL QUICKLY DIMINISH THIS EVENING
WITH MAINLY CLEAR SKIES THEREAFTER.
SATURDAY WILL BE A NEAR REPEAT PERFORMANCE OF TODAY. THE EXCEPTIONS
BEING THAT TEMPERATURES WILL BE A LITTLE COOLER AS SHORTWAVE ENERGY
ACTS TO SHARPEN THE BROAD RIDGE OVER THE NORTHERN PLAINS. THIS WILL
ALLOW COOLER TEMPERATURE TO ADVECT SOUTH INTO THE AREA. WINDS WILL
BE LIGHTER AS SURFACE HIGH PRESSURE WILL TRAVERSE THE FORECAST AREA.
AND FINALLY PRECIPITATION CHANCES SHOULD BE LIMITED TO MAINLY FAR
EASTERN PORTIONS OF CENTRAL NORTH DAKOTA...WITH MORE MID LEVEL
MOISTURE AND LESS CAPPING ALOFT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 243 PM CDT FRI JUN 28 2013
THE MAIN UPPER LEVEL PATTERN IN THE LONG TERM BEGINS AS STRONG
MERIDIONAL FLOW...WITH A SHARP RIDGE OVER WESTERN NORTH AMERICA AND
A LARGE LONGWAVE TROUGH OVER THE EASTERN CONUS.
SATURDAY NIGHT THROUGH MONDAY NIGHT SHOULD BE MAINLY DRY - WITH A
FEW PERIODS OF SLIGHT CHANCES OF SHOWERS/THUNDER WITH SOME
INSTABILITY ARISING FROM EITHER A WEAK SHORTWAVE IMPULSE MOVING
THROUGH THE FLOW OR DAYTIME HEATING INSTABILITY THAT MAY BE ENOUGH
TO CAUSE SOME ISOLATED CONVECTION.
THE GFS AND EC ADVERTISE A STRONGER SHORTWAVE MOVING SOUTHWARD IN
THE NORTHERLY UPPER LEVEL FLOW TUESDAY NIGHT/WEDNESDAY...AND A
SURFACE COLD FRONT SHOULD ACCOMPANY THE UPPER SHORTWAVE. THUS
INCREASED CHANCES OF SHOWERS/THUNDERSHOWERS TUESDAY NIGHT AND
WEDNESDAY.
THE MODELS DIVERGE AFTER THIS WITH A PATTERN CHANGE POSSIBLE AS THE
RIDGE/TROUGH STRUCTURE BREAKS DOWN. KEPT MAINLY SLIGHT CHANCES FOR
CONVECTION WEDNESDAY NIGHT THROUGH FRIDAY OF NEXT WEEK.
LOOKING AT HIGHS MAINLY IN THE UPPER 70S AND LOWER 80S THIS TIME
PERIOD WITH LOWS MAINLY IN THE 50S AND LOWER 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 642 PM CDT FRI JUN 28 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE 00Z TAF PERIOD. CUMULUS
WILL CONTINUE TO DECREASE THIS EVENING LEAVING MAINLY CLEAR SKIES.
GUSTY NORTH / NORTHWEST WINDS WILL ALSO DIMINISH THIS EVENING. A
FEW CUMULUS CLOUDS ARE POSSIBLE AGAIN SATURDAY AFTERNOON WITH WIND
GUSTS IN THE 15-20 KT RANGE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...TWH
LONG TERM...JV
AVIATION...CK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
644 PM CDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 642 PM CDT FRI JUN 28 2013
REGIONAL RADAR MOSAIC EARLY THIS EVENING SHOWS ISOLATED SHOWERS /
THUNDERSTORMS MOVING SOUTH ACROSS PARTS OF EASTERN NORTH DAKOTA.
THE STORMS ARE IN THE AREA WITH THE GREATEST INSTABILITY (1000 J/KG)
WHILE INSTABILITY QUICKLY DECREASES IN CENTRAL AND WESTERN NORTH
DAKOTA. THE LATEST RAP FORECAST SHOWS THE INSTABILITY DECREASING
ACROSS THE FAR EASTERN PART OF THE FORECAST AREA THIS
EVENING...AND LATE AFTERNOON / EARLY EVENING VISIBLE SATELLITE
IMAGERY SHOWS CUMULUS QUICKLY DECREASING. WILL CONTINUE TO CARRY A
SMALL CHANCE OF THUNDERSTORMS IN THE FAR EASTERN PART OF THE
FORECAST AREA FOR ANOTHER COUPLE OF HOURS...BUT THE ACTIVITY
SHOULD WANE THIS EVENING. THE REMAINDER OF THE FORECAST LOOKS
GOOD.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 243 PM CDT FRI JUN 28 2013
MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD WILL BE ISOLATED
THUNDERSTORM CHANCES LATE THIS AFTERNOON INTO THIS EVENING AND AGAIN
SATURDAY AFTERNOON AND EVENING.
CURRENTLY...SURFACE HIGH PRESSURE IS SITUATED OVER THE NORTHERN
ROCKIES AND INTO THE NORTHERN HIGH PLAINS...WITH LOW PRESSURE OVER
THE GREAT LAKES REGION. CUMULUS DEVELOPMENT ACROSS WESTERN AND
CENTRAL NORTH DAKOTA WITH A FEW SHOWERS INDICATED ALONG LAKE
SAKAKAWEA.
BEST CAPE REMAINS ACROSS NORTHERN AND EASTERN NORTH DAKOTA...WHILE
BEST SHEAR IS SITUATED OVER SOUTHWEST NORTH DAKOTA. 28 JUNE 12Z NAM
SOUNDINGS INDICATE A VERY DRY ATMOSPHERE AT BISMARCK AND ESPECIALLY
MINOT AND JAMESTOWN WITH ONLY A VERY THIN MOISTURE LAYER. WESTERN
NORTH DAKOTA APPEARS TO HAVE A BETTER CHANCE OF MORE THAN A SHOWER.
CAPE VALUES ARE LIMITED BUT GOOD SPEED SHEAR EXISTS...WITH 50 KNOTS
OF BULK SHEAR CURRENTLY OVER THE SOUTHWEST. WILL KEEP AN EYE ON THE
RADAR AND LATE AFTERNOON/EVENING POPS WILL BE BASED ON LATEST FRAMES.
ANY CONVECTION THAT WOULD DEVELOP WILL QUICKLY DIMINISH THIS EVENING
WITH MAINLY CLEAR SKIES THEREAFTER.
SATURDAY WILL BE A NEAR REPEAT PERFORMANCE OF TODAY. THE EXCEPTIONS
BEING THAT TEMPERATURES WILL BE A LITTLE COOLER AS SHORTWAVE ENERGY
ACTS TO SHARPEN THE BROAD RIDGE OVER THE NORTHERN PLAINS. THIS WILL
ALLOW COOLER TEMPERATURE TO ADVECT SOUTH INTO THE AREA. WINDS WILL
BE LIGHTER AS SURFACE HIGH PRESSURE WILL TRAVERSE THE FORECAST AREA.
AND FINALLY PRECIPITATION CHANCES SHOULD BE LIMITED TO MAINLY FAR
EASTERN PORTIONS OF CENTRAL NORTH DAKOTA...WITH MORE MID LEVEL
MOISTURE AND LESS CAPPING ALOFT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 243 PM CDT FRI JUN 28 2013
THE MAIN UPPER LEVEL PATTERN IN THE LONG TERM BEGINS AS STRONG
MERIDIONAL FLOW...WITH A SHARP RIDGE OVER WESTERN NORTH AMERICA AND
A LARGE LONGWAVE TROUGH OVER THE EASTERN CONUS.
SATURDAY NIGHT THROUGH MONDAY NIGHT SHOULD BE MAINLY DRY - WITH A
FEW PERIODS OF SLIGHT CHANCES OF SHOWERS/THUNDER WITH SOME
INSTABILITY ARISING FROM EITHER A WEAK SHORTWAVE IMPULSE MOVING
THROUGH THE FLOW OR DAYTIME HEATING INSTABILITY THAT MAY BE ENOUGH
TO CAUSE SOME ISOLATED CONVECTION.
THE GFS AND EC ADVERTISE A STRONGER SHORTWAVE MOVING SOUTHWARD IN
THE NORTHERLY UPPER LEVEL FLOW TUESDAY NIGHT/WEDNESDAY...AND A
SURFACE COLD FRONT SHOULD ACCOMPANY THE UPPER SHORTWAVE. THUS
INCREASED CHANCES OF SHOWERS/THUNDERSHOWERS TUESDAY NIGHT AND
WEDNESDAY.
THE MODELS DIVERGE AFTER THIS WITH A PATTERN CHANGE POSSIBLE AS THE
RIDGE/TROUGH STRUCTURE BREAKS DOWN. KEPT MAINLY SLIGHT CHANCES FOR
CONVECTION WEDNESDAY NIGHT THROUGH FRIDAY OF NEXT WEEK.
LOOKING AT HIGHS MAINLY IN THE UPPER 70S AND LOWER 80S THIS TIME
PERIOD WITH LOWS MAINLY IN THE 50S AND LOWER 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 642 PM CDT FRI JUN 28 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE 00Z TAF PERIOD. CUMULUS
WILL CONTINUE TO DECREASE THIS EVENING LEAVING MAINLY CLEAR SKIES.
GUSTY NORTH / NORTHWEST WINDS WILL ALSO DIMINISH THIS EVENING. A
FEW CUMULUS CLOUDS ARE POSSIBLE AGAIN SATURDAY AFTERNOON WITH WIND
GUSTS IN THE 15-20 KT RANGE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...TWH
LONG TERM...JV
AVIATION...CK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1245 PM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1245 PM CDT THU JUN 27 2013
THUNDER CHANCES AND WIND SPEEDS WILL BE THE CONCERN. FORECAST
THINKING REMAINS ON TRACK AFTER LOOKING AT 15Z RAP/HRRR AND 12Z
MODELS. 15Z HRRR CONTINUES TO SHOW ISOLD SHOWERS THIS AFTERNOON
ACROSS NE NORTH DAKOTA INTO WEST CENTRAL MINNESOTA (WHICH IS
OUTSIDE OF OUR CURRENT FORECASTED POPS). LAPS ANALYSIS INDICATES
MLCAPE 500-700 J/KG WITHIN THIS AREA...SO ISOLD SHOWER/THUNDER IS
POSSIBLE AND WILL ADD TO THE FORECAST FOR THIS AFTERNOON. THE
BETTER SHOWER/THUNDER CHANCES STILL REMAIN ACROSS THE NE FA WHICH
IS CLOSER TO THE UPPER LOW/TROUGH.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 338 AM CDT THU JUN 27 2013
UPPER LOW OVER MANITOBA NEAR BERENS RIVER WILL DROP SOUTHEAST
TODAY TOWARD THE BOUNDARY WATER REGION ALONG MINNESOTA/ONTARIO
FOR TONIGHT. SHORT WAVE WHICH CAUSED SCT STORMS TO MOVE THRU NE
ND/NW MN AS MOVED EAST WITH STORMS NOW OVER NE MN. AS UPPER LOW
MOVES SOUTHEAST EXPECT A RE-GENERATION OF SCATTERED THUNDERSTORMS
OVER NW MN IN COOL POCKET ALOFT. SOUNDINGS SHOW STEEP LAPSE RATES
AND NEGATIVE LIFTED INDICES IN REGION. WILL MAINTAIN IDEA OF CHC
POPS HALLOCK-PARK RAPIDS NORTH AND EAST WITH REST OF THE FCST AREA
SEEING SOME DIURNAL CU FORMATION WITH DAYTIME HEATING. STILL WARM
TODAY...WITH MOST SITES IN THE LOWER TO MID 80S. WILL MAINTAIN
SOME POPS FOR ISOLD/SCT TRW IN NW MN THRU TONIGHT AS LIKE WED
NIGHT COULD SEE A FEW STORMS LAST WELL PAST SUNSET DUE TO DYNAMICS
ALOFT. LOOKS BREEZY-WINDY TODAY WITH WEST-NORTHWEST WINDS GUSTING
TO 25 KTS OR SO IN THE AFTN.
BROAD UPPER TROUGH WILL SETTLE SOUTHWARD FRIDAY SPREADING THE RISK
OF A FEW SHOWERS/STORMS FARTHER WEST INTO ERN ND DURING THIS TIME
PERIOD...THOUGH MAIN CHC WILL REMAIN IN NORTHWEST INTO CENTRAL MN.
LOOK FOR A DROP OF 2-4C IN 850 MB TEMPS ALONG WITH INCREASE IN
OVERALL CLOUD COVER FRI. THIS WILL GIVE HIGH TEMPS ABOUT 5 DEG
COOLER BOTH DAYS WITH HIGHS MOSTLY IN THE 70S. ANOTHER BREEZY-
WINDY DAY WITH GUSTS OVER 25 KTS AT TIMES FROM THE NORTHWEST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 AM CDT THU JUN 27 2013
UPPER TROUGH WILL CONTINUE TO SLOWLY DROP SOUTH FRI NIGHT-SAT AND
WILL KEEP RISK OF A FEW SHOWERS/STORMS THRU THIS PD...WITH BEST
CHC IN MINNESOTA PART OF THE FCST AREA. BY LATE SAT MAIN THREAT
SHIFTS SOUTH INTO CNTRL-SRN MN. WITH COOLING AT 850 MB SATURDAY
WILL SEE HIGHS ONCE AGAIN IN THE 70S.
FOR SUNDAY THROUGH WEDNESDAY...00 UTC GFS/ECMWF IN REASONABLE
AGREEMENT THROUGH 00 UTC TUESDAY... DIVERGING THEREAFTER. BOTH
SHOW A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS AND A BROAD
TROUGH CENTERED ACROSS THE OHIO RIVER VALLEY...PLACING THE
FORECAST AREA IN NORTHWEST FLOW ALOFT. MODEL DIFFERENCES EMERGE
LATE MONDAY THROUGH MID-WEEK WITH THE INTERACTION BETWEEN A
SOUTHWARD PROPAGATING CANADIAN SHORT-WAVE AND THE BROADER TROUGH
TO THE SOUTH. BOTH MODELS SUGGEST THESE FEATURES WILL MERGE
SOMEWHERE ACROSS THE MIDWEST/CENTRAL PLAINS BY WEDNESDAY...BUT
DETAILS ARE SKETCHY AT THIS TIME. FOR NOW...WILL KEEP ALL BLEND
CHANCE POPS MONDAY NIGHT THROUGH WEDNESDAY...ALTHOUGH THIS PAINTS
AN OVERALL POTENTIAL FOR WETTER CONDITIONS THAN WHAT IS EXPECTED.
IT DOES APPEAR LIKELY THAT THE FORECAST AREA WILL REMAIN ON THE
COOL-SIDE OF THE MID-LEVEL THERMAL GRADIENT BETWEEN THE RIDGE TO THE
WEST AND TROUGH TO THE EAST. THIS SHOULD KEEP TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE MID 70S TO LOWER 80S AND LOWS IN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1245 PM CDT THU JUN 27 2013
DRY FCST EXCEPT FOR KBJI FROM MID AFTERNOON THROUGH EVENING WHERE
LINGERING UPPER LOW COULD INSTIGATE SCT TSTM ACTIVITY. GUSTY
CHARACTER OF NW WNDS TO DIMINISH TWD SUNSET...ENOUGH GRADIENT WILL
KEEP SPEEDS ABOVE 10 KTS THOUGH. TROUGH TO NORTHEAST TO MOVE BACK
TOWARD KBJI-KTVF OVERNIGHT...BRINGING LOW VFR DECK TO THOSE
SITES.
&&
.HYDROLOGY...
ISSUED AT 1245 PM CDT THU JUN 27 2013
RUNOFF CONTINUES TO MAKES ITS WAY INTO THE RED RIVER FROM AREA
TRIBUTARIES. ONLY MINOR UPDATES WERE MADE TO MOST RIVER FORECAST
POINTS THIS MORNING. THE RED RIVER AT FARGO IS FORECAST TO CREST
NEAR MAJOR FLOOD STAGE TOWARDS LATE FRIDAY OR FRIDAY NIGHT. RISES
ARE EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS ON CENTRAL AND
NORTHERN SECTIONS OF THE RED WITH A FEW FORECAST POINTS EXPECTED TO
RISE ABOVE MINOR FLOOD STAGE. THE RIVER FLOOD WARNING FOR WAHPETON
WAS CANCELLED AS RIVER LEVELS CONTINUE TO FALL. HOWEVER EXPECTED
RELEASES FROM WHITE ROCK DAM MAY SLOW THE RECESSION OF RIVER
LEVELS.
THE FLOOD ADVISORY FOR CASS CO AND THE AREAL FLOOD WARNING FOR PARTS
OF WILKIN...CLAY AND RICHLAND COUNTIES WAS ALLOWED TO EXPIRE.
CONDITIONS HAVE MARKEDLY IMPROVED OVER THE PAST 24 HOURS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...WJB
HYDROLOGY...MAKOWSKI
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1227 PM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 1227 PM CDT THU JUN 27 2013
SUNNY SKIES AREA WIDE EARLY THIS AFTERNOON. MAY SEE A FEW CU
DEVELOP...BUT OVERALL EXPECT SKY COVER TO REMAIN LOW. WINDS ARE
GUSTING TO AROUND 30 MPH AT TIMES...AND WILL CONTINUE TO DO SO
THROUGH EARLY THIS EVENING BEFORE SUBSIDING.
OVERALL...CHANGES WERE MINOR FOR THE EARLY AFTERNOON FORECAST
PACKAGE.
UPDATE ISSUED AT 933 AM CDT THU JUN 27 2013
ONLY MINIMAL CHANGES WERE MADE FOR THIS MID MORNING FORECAST
UPDATE. INCREASED WINDS JUST A BIT...ESPECIALLY SOUTHWEST...WHERE
LATEST GUIDANCE INDICATES A FEW GUSTS TO 30KTS AT TIMES.
OTHERWISE...SHOULD BE A DRY/SUNNY/WARM DAY WITH A STEADY NORTHWEST
WIND...BREEZY AT TIMES.
UPDATE ISSUED AT 640 AM CDT THU JUN 27 2013
PLEASANT MORNING WEATHERWISE ACROSS THE AREA WITH MOSTLY CLEAR
SKIES. SOME HIGH CLOUDS EVIDENT ACROSS THE SOUTH...BUT THESE
CLOUDS CONTINUE TO PUSH INTO SOUTH DAKOTA. NO CHANGES TO THE
FORECAST OTHER THAN FRESHENING UP THE NEAR TERM HOURLY FORECASTS.
BREEZY NORTHWEST WINDS WILL DEVELOP BY MID MORNING WITH WARM
TEMPERATURES INTO THE 80S EXPECTED TODAY BEFORE A SLIGHT COOL DOWN
OCCURS FRIDAY INTO THE WEEKEND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT THU JUN 27 2013
SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM
FOR TODAY.
HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS
BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED
ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST
FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW
PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE
TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND
HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND
THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE.
HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS
SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR
NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE.
HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF
THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT.
WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A
CLEAR AND QUIET NIGHT EXPECTED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU JUN 27 2013
NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST.
MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN
PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY
WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL
GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20
KTS.
AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER
LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL
RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE
WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS
NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP
AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW
ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED
LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN
PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE
OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT
TO TIME AT THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1227 PM CDT THU JUN 27 2013
VFR CONDITIONS ALL TERMINALS FOR THE 18Z PERIOD. BREEZY NORTHWEST
WINDS EXPECTED THROUGH SUNSET...WITH GUSTS UP TO AROUND 25 KTS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JNS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 AM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 955 AM CDT THU JUN 27 2013
THUNDER CHANCES AND WIND SPEEDS WILL BE THE CONCERN. FORECAST
THINKING REMAINS ON TRACK AFTER LOOKING AT 12Z NAM/RAP/HRRR.
INCREASED WINDS A BIT WITH THE RAP SHOWING 850MB WINDS AROUND 30
KNTS...AND 925MB WINDS AROUND 25 KNTS (WHICH SHOULD LEAD TO SFC
WINDS 20-30 MPH WITH GUSTS TO 35 MPH). 12Z HRRR DOES SHOW ISOLD
SHOWERS THIS AFTERNOON ACROSS NE NORTH DAKOTA INTO WEST CENTRAL
MINNESOTA (WHICH IS OUTSIDE OF OUR CURRENT FORECASTED POPS). THIS
AREA IS FURTHER AWAY FROM UPPER LEVEL COLDER TEMPERATURES...AND
LESS LIKELY TO SEE SHOWERS. WILL MONITOR AND TAKE ANOTHER LOOK
WITH THE NEXT UPDATE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 338 AM CDT THU JUN 27 2013
UPPER LOW OVER MANITOBA NEAR BERENS RIVER WILL DROP SOUTHEAST
TODAY TOWARD THE BOUNDARY WATER REGION ALONG MINNESOTA/ONTARIO
FOR TONIGHT. SHORT WAVE WHICH CAUSED SCT STORMS TO MOVE THRU NE
ND/NW MN AS MOVED EAST WITH STORMS NOW OVER NE MN. AS UPPER LOW
MOVES SOUTHEAST EXPECT A RE-GENERATION OF SCATTERED THUNDERSTORMS
OVER NW MN IN COOL POCKET ALOFT. SOUNDINGS SHOW STEEP LAPSE RATES
AND NEGATIVE LIFTED INDICES IN REGION. WILL MAINTAIN IDEA OF CHC
POPS HALLOCK-PARK RAPIDS NORTH AND EAST WITH REST OF THE FCST AREA
SEEING SOME DIURNAL CU FORMATION WITH DAYTIME HEATING. STILL WARM
TODAY...WITH MOST SITES IN THE LOWER TO MID 80S. WILL MAINTAIN
SOME POPS FOR ISOLD/SCT TRW IN NW MN THRU TONIGHT AS LIKE WED
NIGHT COULD SEE A FEW STORMS LAST WELL PAST SUNSET DUE TO DYNAMICS
ALOFT. LOOKS BREEZY-WINDY TODAY WITH WEST-NORTHWEST WINDS GUSTING
TO 25 KTS OR SO IN THE AFTN.
BROAD UPPER TROUGH WILL SETTLE SOUTHWARD FRIDAY SPREADING THE RISK
OF A FEW SHOWERS/STORMS FARTHER WEST INTO ERN ND DURING THIS TIME
PERIOD...THOUGH MAIN CHC WILL REMAIN IN NORTHWEST INTO CENTRAL MN.
LOOK FOR A DROP OF 2-4C IN 850 MB TEMPS ALONG WITH INCREASE IN
OVERALL CLOUD COVER FRI. THIS WILL GIVE HIGH TEMPS ABOUT 5 DEG
COOLER BOTH DAYS WITH HIGHS MOSTLY IN THE 70S. ANOTHER BREEZY-
WINDY DAY WITH GUSTS OVER 25 KTS AT TIMES FROM THE NORTHWEST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 AM CDT THU JUN 27 2013
UPPER TROUGH WILL CONTINUE TO SLOWLY DROP SOUTH FRI NIGHT-SAT AND
WILL KEEP RISK OF A FEW SHOWERS/STORMS THRU THIS PD...WITH BEST
CHC IN MINNESOTA PART OF THE FCST AREA. BY LATE SAT MAIN THREAT
SHIFTS SOUTH INTO CNTRL-SRN MN. WITH COOLING AT 850 MB SATURDAY
WILL SEE HIGHS ONCE AGAIN IN THE 70S.
FOR SUNDAY THROUGH WEDNESDAY...00 UTC GFS/ECMWF IN REASONABLE
AGREEMENT THROUGH 00 UTC TUESDAY... DIVERGING THEREAFTER. BOTH
SHOW A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS AND A BROAD
TROUGH CENTERED ACROSS THE OHIO RIVER VALLEY...PLACING THE
FORECAST AREA IN NORTHWEST FLOW ALOFT. MODEL DIFFERENCES EMERGE
LATE MONDAY THROUGH MID-WEEK WITH THE INTERACTION BETWEEN A
SOUTHWARD PROPAGATING CANADIAN SHORT-WAVE AND THE BROADER TROUGH
TO THE SOUTH. BOTH MODELS SUGGEST THESE FEATURES WILL MERGE
SOMEWHERE ACROSS THE MIDWEST/CENTRAL PLAINS BY WEDNESDAY...BUT
DETAILS ARE SKETCHY AT THIS TIME. FOR NOW...WILL KEEP ALL BLEND
CHANCE POPS MONDAY NIGHT THROUGH WEDNESDAY...ALTHOUGH THIS PAINTS
AN OVERALL POTENTIAL FOR WETTER CONDITIONS THAN WHAT IS EXPECTED.
IT DOES APPEAR LIKELY THAT THE FORECAST AREA WILL REMAIN ON THE
COOL-SIDE OF THE MID-LEVEL THERMAL GRADIENT BETWEEN THE RIDGE TO THE
WEST AND TROUGH TO THE EAST. THIS SHOULD KEEP TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE MID 70S TO LOWER 80S AND LOWS IN
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 653 AM CDT THU JUN 27 2013
EXPECTING VFR CONDITIONS TODAY. BIG STORY WILL BE EXPECTED GUSTY
WEST-NORTHWEST WINDS IN THE 15 TO 30 KT RANGE...WINDIEST IN THE
PRAIRIES. GOOD MIXING TODAY SHOULD HELP TRANSPORT 30 KTS WINDS TO
THE SFC IN GUSTS. SOME CU DEVELOPMENT TODAY ALONG WITH SOME MID
AND HIGH LEVEL. DID GO WITH VCTS IN BEMIDJI IN THE AFTN...BUT
TIMING IS QUITE DIFFICULT THIS TIME OUT. DID NOT INCLUDE TVF ATTM.
&&
.HYDROLOGY...
ISSUED AT 945 PM CDT WED JUN 26 2013
ALL RIVERS AROUND FARGO CONTINUE TO SEE RISES IN THE LEVELS. IT
APPEARS THAT THE RED AT FARGO WILL APPROACH MAJOR FLOOD STAGE WITHIN
THE NEXT COUPLE OF DAYS...AND THE LATEST GUIDANCE SHOWS LITTLE
CHANGE FOR THE FARGO FORECAST POINT. SIMULATIONS INDICATE THAT
POINTS DOWNSTREAM OF FARGO WILL ALSO APPROACH OR EXCEED MINOR FLOOD
STAGE IN SEVERAL DAYS...FROM HALSTAD THROUGH OSLO MINNESOTA. AN
AREAL FLOOD WARNING REMAINS IN EFFECT FOR WILKIN AND RICHLAND
COUNTIES...AND A FLOOD ADVISORY HAS BEEN POSTED FOR CASS COUNTY.
THE TWO RIVERS RIVER AT HALLOCK HAS RECEDED BELOW ACTION STAGE AND
IS EXPECTED TO REMAIN BELOW ACTION STAGE FOR THE NEXT SEVERAL DAYS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...RIDDLE
HYDROLOGY...HOPKINS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
933 AM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 933 AM CDT THU JUN 27 2013
ONLY MINIMAL CHANGES WERE MADE FOR THIS MID MORNING FORECAST
UPDATE. INCREASED WINDS JUST A BIT...ESPECIALLY SOUTHWEST...WHERE
LATEST GUIDANCE INDICATES A FEW GUSTS TO 30KTS AT TIMES.
OTHERWISE...SHOULD BE A DRY/SUNNY/WARM DAY WITH A STEADY NORTHWEST
WIND...BREEZY AT TIMES.
UPDATE ISSUED AT 640 AM CDT THU JUN 27 2013
PLEASANT MORNING WEATHERWISE ACROSS THE AREA WITH MOSTLY CLEAR
SKIES. SOME HIGH CLOUDS EVIDENT ACROSS THE SOUTH...BUT THESE
CLOUDS CONTINUE TO PUSH INTO SOUTH DAKOTA. NO CHANGES TO THE
FORECAST OTHER THAN FRESHENING UP THE NEAR TERM HOURLY FORECASTS.
BREEZY NORTHWEST WINDS WILL DEVELOP BY MID MORNING WITH WARM
TEMPERATURES INTO THE 80S EXPECTED TODAY BEFORE A SLIGHT COOL DOWN
OCCURS FRIDAY INTO THE WEEKEND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT THU JUN 27 2013
SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM
FOR TODAY.
HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS
BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED
ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST
FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW
PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE
TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND
HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND
THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE.
HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS
SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR
NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE.
HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF
THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT.
WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A
CLEAR AND QUIET NIGHT EXPECTED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU JUN 27 2013
NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST.
MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN
PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY
WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL
GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20
KTS.
AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER
LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL
RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE
WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS
NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP
AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW
ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED
LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN
PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE
OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT
TO TIME AT THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 933 AM CDT THU JUN 27 2013
VFR CONDITIONS ARE FORECAST FOR THE 12 UTC TAF CYCLE ACROSS WESTERN
AND CENTRAL NORTH DAKOTA. BREEZY NORTHWEST WINDS ARE EXPECTED DURING
THE LATE MORNING THROUGH SUNSET...WITH GUSTS OF 20-25 KTS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JNS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
640 AM CDT THU JUN 27 2013
.UPDATE...
ISSUED AT 640 AM CDT THU JUN 27 2013
PLEASANT MORNING WEATHERWISE ACROSS THE AREA WITH MOSTLY CLEAR
SKIES. SOME HIGH CLOUDS EVIDENT ACROSS THE SOUTH...BUT THESE
CLOUDS CONTINUE TO PUSH INTO SOUTH DAKOTA. NO CHANGES TO THE
FORECAST OTHER THAN FRESHENING UP THE NEAR TERM HOURLY FORECASTS.
BREEZY NORTHWEST WINDS WILL DEVELOP BY MID MORNING WITH WARM
TEMPERATURES INTO THE 80S EXPECTED TODAY BEFORE A SLIGHT COOL DOWN
OCCURS FRIDAY INTO THE WEEKEND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT THU JUN 27 2013
SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM
FOR TODAY.
HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS
BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED
ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST
FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW
PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE
TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND
HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND
THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE.
HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS
SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR
NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE.
HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF
THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT.
WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A
CLEAR AND QUIET NIGHT EXPECTED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU JUN 27 2013
NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST.
MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN
PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY
WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL
GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20
KTS.
AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER
LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL
RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE
WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS
NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP
AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW
ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED
LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN
PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE
OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT
TO TIME AT THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED
AT 640 AM CDT THU JUN 27 2013
VFR CONDITIONS ARE FORECAST FOR THE 12 UTC TAF CYCLE ACROSS WESTERN
AND CENTRAL NORTH DAKOTA. BREEZY NORTHWEST WINDS ARE EXPECTED DURING
THE LATE MORNING THROUGH SUNSET...WITH GUSTS OF 20-25 KTS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JNS
SHORT TERM...AYD
LONG TERM...JNS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
330 AM CDT THU JUN 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT THU JUN 27 2013
SUNNY SKIES AND NORTHWEST BREEZES WILL HIGHLIGHT THE SHORT TERM
FOR TODAY.
HARD TO GO AGAINST THE 00 UTC STATISTICAL GUIDANCE SUITE AND ITS
BUILT IN CLIMATOLOGY GIVEN A PRETTY STANDARD SUMMER DAY EXPECTED
ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND USED THIS FOR MOST
FORECAST FIELDS. GOOD MIXING SOUTHWEST OF A WEAK SURFACE LOW
PROPAGATING INTO THE GREAT LAKES IS EXPECTED AREA WIDE
TODAY...SUPPORTING NORTHWEST BREEZES WITH GUSTS TO 25 KTS AND
HIGHS MIXING OUT INTO UPPER 70S ACROSS THE TURTLE MOUNTAINS AND
THE 80S ELSEWHERE. LEFT THE FORECAST PRECIPITATION FREE.
HOWEVER...THE 00 UTC 4 KM WRF...05 UTC HRRR AND THE 00 UTC GFS
SUGGEST THE POTENTIAL FOR AN ISOLATED SHOWER OR THUNDERSTORM FAR
NORTH THIS AFTERNOON AS A WEAK IMPULSE CRESTS THE RIDGE.
HOWEVER...GIVEN WEAK MID LEVEL LAPSE RATES AND THE REMAINDER OF
THE 00 UTC DETERMINISTIC MODELS BEING DRY...LEFT THE MENTION OUT.
WEAK SURFACE HIGH PRESSURE BUILDS INTO THE AREA TONIGHT...WITH A
CLEAR AND QUIET NIGHT EXPECTED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU JUN 27 2013
NO SIGNIFICANT CHANGE FROM PAST DAYS WITH EXTENDED FORECAST.
MODELS CONTINUE TO DEPICT WESTERN RIDGE AND EASTERN TROUGH IN
PLACE...LEAVING NORTHERN PLAINS IN NORTHWEST FLOW INTO THE EARLY
WEEKEND. FRIDAY SHOULD BE A LITTLE COOLER...THOUGH HIGHS STILL
GETTING NEAR 80 MOST LOCATIONS ALONG WITH NORTHERLY WINDS 10-20
KTS.
AGAIN THE MODELS BEGIN TO DIVERGE WITH HANDLING OF THE UPPER
LOW ALTHOUGH THEY ARE IN DECENT AGREEMENT KEEPING UPPER LEVEL
RIDGE IN PLACE NEAR THE WEST COAST. GFS IS A LITTLE MORE AGGRESSIVE
WITH BRINGING SHORTWAVE TROUGH AROUND UPPER LOW AND ACROSS
NORTHERN PLAINS TUESDAY. BOTH MODELS HINT AT REX BLOCK SETTING UP
AS RIDGE TRIES TO BUILD EASTWARD ACROSS CANADA WITH UPPER LOW
ACROSS THE CENTRAL PLAINS. BOTTOM LINE FOR OUR AREA IS CONTINUED
LOW POPS OVER THE WEEKEND...MAINLY EAST...WITH HIGHER POPS IN
PLACE EARLY/MID WEEK AS OUR REGION FALLS MORE UNDER THE INFLUENCE
OF THE UPPER LEVEL LOW AND EMBEDDED SHORTWAVES THAT ARE DIFFICULT
TO TIME AT THIS POINT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 330 AM CDT THU JUN 27 2013
VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF CYCLE ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. BREEZY NORTHWEST WINDS ARE
EXPECTED DURING THE LATE MORNING THROUGH SUNSET...WITH GUSTS OF
20-25 KTS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...JNS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
655 AM EDT THU JUN 27 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL CONTINUE TO MOVE NORTHEAST OF THE
OHIO VALLEY TODAY...WITH A LARGE UPPER LEVEL TROUGH OF LOW
PRESSURE SITUATING ITSELF OVER THE EASTERN GREAT LAKES THROUGH THE
WEEKEND. OCCASIONAL CHANCES OF SHOWERS AND THUNDERSTORMS WILL BE
EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SHORTWAVE TROUGH IS CURRENTLY LOCATED OVER THE ILN CWA...AS A
SURFACE LOW DEVELOPS UNDERNEATH. SCATTERED SHOWERS AND
THUNDERSTORMS CONTINUE TO DEVELOP AS A RESULT OF THESE FEATURES.
IT HAS BEEN INTERESTING TO WATCH THE VARYING MOTIONS OF THESE
SLOW-MOVING CONVECTIVE CLUSTERS...CAUGHT IN DIFFERENT AREAS OF
FLOW AROUND THE TROUGH AND SURFACE LOW. OVERALL...AS THIS ENTIRE
SYSTEM MOVES TO THE EAST...THE POPS WILL DECREASE FROM WEST TO
EAST THROUGH THE MORNING HOURS (LEADING TO A DIURNAL LULL).
THE LARGER-SCALE COMPUTER MODELS CONTINUE TO OVERDO PRECIPITATION
NORTH OF THE OHIO RIVER ALL THE WAY INTO PENNSYLVANIA...WHILE ALSO
STRUGGLING TO PICK UP ON THE SOUTHWARD-PROPAGATING CONVECTION IN
THE TENNESSEE VALLEY. HRRR RUNS ARE ADAMANT IN KEEPING ANY THREAT
OF HEAVY RAINFALL SOUTH AND EAST OF THE CWA...LEADING TO
CONFIDENCE ENOUGH TO CLEAR OUT THE FLASH FLOOD WATCH.
MOISTURE WILL NOT BE QUICK TO MOVE OUT TODAY...LEADING TO
INCREASES IN THE SKY GRIDS AND DECREASES IN THE MAX TEMP FORECAST.
CLEARING APPEARS MOST LIKELY IN THE SW CWA...WHERE HIGHS IN THE
MID 80S ARE STILL BEING FORECAST. THE INFLUENCE OF THE TROUGH AND
NW FLOW ALOFT WILL COOL TEMPS BY A FEW DEGREES AT HIGHER LEVELS...WHICH
SHOULD ALLOW FOR SOME INSTABILITY (ESPECIALLY IN THE WESTERN
CWA...PERHAPS AS HIGH AS 1500 J/KG BUT MORE LIKELY AROUND 1000
J/KG). THERE SHOULD ALSO BE ENOUGH LIFT WITH THE LARGE SCALE
TROUGH STARTING TO ASSERT ITS INFLUENCE AFTER THE PASSAGE OF THE
MORNING SHORTWAVE...WITH PRECIPITATION CHANCES SLIGHTLY FAVORED IN
THE NE CWA (CLOSER TO THE DEEPER MOISTURE AND THE TROUGH). MIGHT
BE JUST ENOUGH OF THE COMBINATION OF SHEAR AND INSTABILITY TO
SUPPORT A FEW STRONG TO SEVERE STORMS...BUT THIS WOULD BE MORE OF
A RANDOM CELLULAR CONVECTIVE EVENT...RATHER A THAN WELL-FORCED
ORGANIZED SYSTEM. NOT A HUGE RISK...BUT WORTH A HEADS-UP IN THE
HWO...AND THE SPC 5% LOOKS GOOD GIVEN THE CURRENT ASSESSMENT.
NOT A BIG SPREAD IN TEMPS TODAY IN THE GUIDANCE...WITH THE
FORECAST NEAR OR JUST BELOW THE CONSENSUS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
HIGH-RES MODELS DEPICT THE DEVELOPMENT OF STRONG TO SEVERE
THUNDERSTORMS OVER WISCONSIN TODAY...EVENTUALLY MOVING ON A
SOUTHEASTERLY TRAJECTORY FROM THERE AFTER SUNSET. THERE MIGHT BE A
LITTLE BIT OF SHORTWAVE ENERGY AS HEIGHT FALLS MOVE SE AT THE NOSE
OF A 500MB NORTHWESTERLY JET...POINTING DOWN INTO THE SW ILN CWA
DURING THE OVERNIGHT HOURS. AFTER RAMPING POPS DOWN
DIURNALLY...HAVE SHOWN A SLIGHT INCREASE OVERNIGHT AGAIN. THERE
APPEARS TO STILL BE ELEVATED INSTABILITY AVAILABLE...ALONG WITH
INCREASING SHEAR THANKS TO THE JET. SO...IF THIS ACTIVITY DOES
SURVIVE ALL THE WAY TO INDIANA AND OHIO...THERE COULD BE SOME HAIL
ALONG WITH IT.
THE SPECIFICS OF THE CONVECTIVE FORECAST BECOME MORE CONVOLUTED
FROM FRIDAY THROUGH THE WEEKEND...AS THE LARGE SCALE UPPER TROUGH
OVER SOUTHEASTERN CANADA GROWS AND RETROGRADES INTO THE OHIO
VALLEY. SUCH A PATTERN IN THE SUMMER USUALLY SUPPORTS DAILY
DIURNAL INSTABILITY (AIDED BY THE RELATIVE COOLER CONDITIONS
ALOFT)...COMBINING WITH WHATEVER WEAK FORCING CAN COME THROUGH TO
PROMOTE OCCASIONAL CONVECTIVE CHANCES.
FRIDAY LOOKS SIMILAR TO THURSDAY...WITH OVERALL DIURNAL
DEVELOPMENT...AND FAVORING THE NORTHEASTERN CWA FOR COVERAGE
AGAIN. ON SATURDAY...A MUCH LARGER LOBE OF VORTICITY WILL ROTATE
SOUTH THROUGH THE GREAT LAKES...PROMPTING A MUCH DIFFERENT
SCENARIO IN THE FORECAST. POPS AND CLOUDS ARE BOTH ON THE INCREASE
FOR SATURDAY (AND STARTING BOTH OF THESE ADJUSTMENTS RATHER EARLY
IN THE NORTH)...ALONG WITH A DROP IN MAX TEMPS. THIS TROUGH WILL CLOSE
OFF AS AN ELONGATED UPPER LOW OVER THE OHIO VALLEY ON SUNDAY. THE
TROUGH WILL FORCE POPS THROUGH THE WEEKEND...WITH LIKELY POPS
SATURDAY DURING THE DIURNAL PERIOD...AND HIGH CHANCE FOR SUNDAY.
AFTER IT IS MORE CERTAIN WHERE THE TROUGH WILL CLOSE OFF ON
SUNDAY...LIKELY POPS MAY ALSO BE NEEDED THERE...AS A SSW-TO-NNE
AXIS OF MOISTURE AND FORCING WILL BE PRESENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
VERY UNSETTLED PATTERN TO DEVELOP AS AMPLIFIED LONGWAVE FLOW SETS
UP AND PERSISTS THROUGH THIS PERIOD. COULDNT REALLY FIND A DECENT
PERIOD TO INDICATE PROLONGED DRY CONDITIONS...WITH LONGWAVE TROUGH
DEVELOPING/DEEPENING SW TO NE ALONG AND WEST OF THE APPALACHIAN
CHAIN. TWO MASSIVE RIDGES...ONE OVER THE WEST CONUS AND ONE OVER
THE ATLANTIC...RETROGRADE AND AMPLIFY THROUGH THE PERIOD WITH THE
WEAKNESS/TROUGH BETWEEN THE TWO ALSO GAINING AMPLITUDE. NEGATIVE
HEIGHT ANOMALIES ARE SIGNIFICANT AS THE TROUGH DEEPENS ESPECIALLY
TO THE SOUTH OF THE OHIO VALLEY. SUCH A DEEP TROUGH IN THE HEART
OF SUMMER MEANS THAT DAILY FLAREUPS OF CONVECTION ARE LIKELY...AND
WILL BE ESPECIALLY LIKELY TIED TO WEAK WAVES MOVING THROUGH THE
NWLY FLOW UNDERNEATH THE TROUGH EARLY IN THE PERIOD...AND IN THE
SLY FLOW AHEAD OF THE TROUGH LATE IN THE PERIOD AS THE TROUGH AXIS
DRIFTS TO THE WEST. LACK OF SCOURING OF THE LOW LEVEL MOISTURE
FIELD MEANS THERE WILL BE PLENTY OF MOISTURE AND MARGINAL INSTBY
FOR DAILY ROUNDS OF SCT STORMS TIED TO THE DIURNAL HEATING CYCLE.
WAVES TO KEY ON /AT LEAST IN THE SHORT TERM/ ARRIVE BOTH FRIDAY
AND SATURDAY SO THESE DAYS HAVE RELATIVELY HIGHER RAIN
CHANCES...BUT THERE WILL LIKELY BE MANY MORE OF THESE WAVES INTO
EARLY NEXT WEEK. TEMPERATURES...WHILE THEY WILL BE A BIT BELOW
NORMAL...WON/T BE TOO COOL GIVEN THE CORE OF THE 850MB TEMP/500MB
HEIGHT ANOMALIES QUICKLY DIG/RETROGRADE SOUTH AND WEST OF THE
AREA. CERTAINLY NO 90S THE FORECAST...BUT A LONGER OF PERIOD OF
UPPER 70S TO MID 80S AND RATHER DAMP/MUGGY CONDITIONS IS IN THE
OFFING.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
WEAK LOW PRESSURE AND WEAK COLD FRONT WILL SLOWLY PUSH EAST
THROUGH OUR REGION THIS MORNING. SOME FORCING IN THE UPPER LEVELS
ON THE BACK SIDE OF THE WEAK LOW WILL CONTINUE THE THREAT FOR
SHOWERS NEAR THE NRN TAF SITES THROUGH 14Z. BIGGEST CONCERN THIS
MORNING IS THE IFR CIGS...SOME OF WHICH ARE BELOW NEAR OR BELOW
AIRPORT MINIMUMS. IT WILL TAKE AWHILE FOR THESE CIGS TO RISE TO
ABOVE VFR DUE TO DAYTIME HEATING...BUT SHOULD OCCUR BETWEEN 16Z
AND 19Z.
FOR THIS AFTERNOON INTO TONIGHT...GREAT LAKES AND OHIO VALLEY
REGION WILL REMAIN IN A NORTHWEST FLOW ALOFT...ALLOWING OCCASIONAL
DISTURBANCES TO DROP INTO THE REGION. THE AIRMASS SHOULD
DESTABILIZE FOR SOME SHOWER/THUNDERSTORM DEVELOPMENT. SOME MODELS
SUGGEST THAT A SURFACE TROF AXIS MAY PROVIDE SOME LOW LEVEL
FORCING AS WELL. THINK COVERAGE WILL BE IN THE 30 TO 40 PERCENT
RANGE WITH PERHAPS THE KCMH/KLCK HAVING THE HIGHEST THREAT. GIVEN
THAT THE CONVECTION MAY BE DISORGANIZED...HAVE JUST USED THE
VCTS/CB AT THE TAF SITES FROM 19Z TO 00Z. FOR THE OVERNIGHT...CANNOT
RULE OUR SOME LINGERING SHOWER/THUNDERSTORM ACTIVITY...ESPECIALLY
AS SOME MODELS SUGGEST SOME WEAKENING CONVECTION DROPPING DOWN FROM
WISCONSIN. DO NOT WANT TO HOLD ONTO MANY HOURS OF VCTS/CB...SO
WILL LATER TAF ISSUANCES DICTATE TO SEE WHAT COVERAGE MAY OCCUR.
OUTLOOK...THUNDERSTORMS POSSIBLE THROUGH MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...BINAU
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
403 AM EDT THU JUN 27 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL CONTINUE TO MOVE NORTHEAST OF THE
OHIO VALLEY TODAY...WITH A LARGE UPPER LEVEL TROUGH OF LOW
PRESSURE SITUATING ITSELF OVER THE EASTERN GREAT LAKES THROUGH THE
WEEKEND. OCCASIONAL CHANCES OF SHOWERS AND THUNDERSTORMS WILL BE
EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SHORTWAVE TROUGH IS CURRENTLY LOCATED OVER THE ILN CWA...AS A
SURFACE LOW DEVELOPS UNDERNEATH. SCATTERED SHOWERS AND
THUNDERSTORMS CONTINUE TO DEVELOP AS A RESULT OF THESE FEATURES.
IT HAS BEEN INTERESTING TO WATCH THE VARYING MOTIONS OF THESE
SLOW-MOVING CONVECTIVE CLUSTERS...CAUGHT IN DIFFERENT AREAS OF
FLOW AROUND THE TROUGH AND SURFACE LOW. OVERALL...AS THIS ENTIRE
SYSTEM MOVES TO THE EAST...THE POPS WILL DECREASE FROM WEST TO
EAST THROUGH THE MORNING HOURS (LEADING TO A DIURNAL LULL).
THE LARGER-SCALE COMPUTER MODELS CONTINUE TO OVERDO PRECIPITATION
NORTH OF THE OHIO RIVER ALL THE WAY INTO PENNSYLVANIA...WHILE ALSO
STRUGGLING TO PICK UP ON THE SOUTHWARD-PROPAGATING CONVECTION IN
THE TENNESSEE VALLEY. HRRR RUNS ARE ADAMANT IN KEEPING ANY THREAT
OF HEAVY RAINFALL SOUTH AND EAST OF THE CWA...LEADING TO
CONFIDENCE ENOUGH TO CLEAR OUT THE FLASH FLOOD WATCH.
MOISTURE WILL NOT BE QUICK TO MOVE OUT TODAY...LEADING TO
INCREASES IN THE SKY GRIDS AND DECREASES IN THE MAX TEMP FORECAST.
CLEARING APPEARS MOST LIKELY IN THE SW CWA...WHERE HIGHS IN THE
MID 80S ARE STILL BEING FORECAST. THE INFLUENCE OF THE TROUGH AND
NW FLOW ALOFT WILL COOL TEMPS BY A FEW DEGREES AT HIGHER LEVELS...WHICH
SHOULD ALLOW FOR SOME INSTABILITY (ESPECIALLY IN THE WESTERN
CWA...PERHAPS AS HIGH AS 1500 J/KG BUT MORE LIKELY AROUND 1000
J/KG). THERE SHOULD ALSO BE ENOUGH LIFT WITH THE LARGE SCALE
TROUGH STARTING TO ASSERT ITS INFLUENCE AFTER THE PASSAGE OF THE
MORNING SHORTWAVE...WITH PRECIPITATION CHANCES SLIGHTLY FAVORED IN
THE NE CWA (CLOSER TO THE DEEPER MOISTURE AND THE TROUGH). MIGHT
BE JUST ENOUGH OF THE COMBINATION OF SHEAR AND INSTABILITY TO
SUPPORT A FEW STRONG TO SEVERE STORMS...BUT THIS WOULD BE MORE OF
A RANDOM CELLULAR CONVECTIVE EVENT...RATHER A THAN WELL-FORCED
ORGANIZED SYSTEM. NOT A HUGE RISK...BUT WORTH A HEADS-UP IN THE
HWO...AND THE SPC 5% LOOKS GOOD GIVEN THE CURRENT ASSESSMENT.
NOT A BIG SPREAD IN TEMPS TODAY IN THE GUIDANCE...WITH THE
FORECAST NEAR OR JUST BELOW THE CONSENSUS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
HIGH-RES MODELS DEPICT THE DEVELOPMENT OF STRONG TO SEVERE
THUNDERSTORMS OVER WISCONSIN TODAY...EVENTUALLY MOVING ON A
SOUTHEASTERLY TRAJECTORY FROM THERE AFTER SUNSET. THERE MIGHT BE A
LITTLE BIT OF SHORTWAVE ENERGY AS HEIGHT FALLS MOVE SE AT THE NOSE
OF A 500MB NORTHWESTERLY JET...POINTING DOWN INTO THE SW ILN CWA
DURING THE OVERNIGHT HOURS. AFTER RAMPING POPS DOWN
DIURNALLY...HAVE SHOWN A SLIGHT INCREASE OVERNIGHT AGAIN. THERE
APPEARS TO STILL BE ELEVATED INSTABILITY AVAILABLE...ALONG WITH
INCREASING SHEAR THANKS TO THE JET. SO...IF THIS ACTIVITY DOES
SURVIVE ALL THE WAY TO INDIANA AND OHIO...THERE COULD BE SOME HAIL
ALONG WITH IT.
THE SPECIFICS OF THE CONVECTIVE FORECAST BECOME MORE CONVOLUTED
FROM FRIDAY THROUGH THE WEEKEND...AS THE LARGE SCALE UPPER TROUGH
OVER SOUTHEASTERN CANADA GROWS AND RETROGRADES INTO THE OHIO
VALLEY. SUCH A PATTERN IN THE SUMMER USUALLY SUPPORTS DAILY
DIURNAL INSTABILITY (AIDED BY THE RELATIVE COOLER CONDITIONS
ALOFT)...COMBINING WITH WHATEVER WEAK FORCING CAN COME THROUGH TO
PROMOTE OCCASIONAL CONVECTIVE CHANCES.
FRIDAY LOOKS SIMILAR TO THURSDAY...WITH OVERALL DIURNAL
DEVELOPMENT...AND FAVORING THE NORTHEASTERN CWA FOR COVERAGE
AGAIN. ON SATURDAY...A MUCH LARGER LOBE OF VORTICITY WILL ROTATE
SOUTH THROUGH THE GREAT LAKES...PROMPTING A MUCH DIFFERENT
SCENARIO IN THE FORECAST. POPS AND CLOUDS ARE BOTH ON THE INCREASE
FOR SATURDAY (AND STARTING BOTH OF THESE ADJUSTMENTS RATHER EARLY
IN THE NORTH)...ALONG WITH A DROP IN MAX TEMPS. THIS TROUGH WILL CLOSE
OFF AS AN ELONGATED UPPER LOW OVER THE OHIO VALLEY ON SUNDAY. THE
TROUGH WILL FORCE POPS THROUGH THE WEEKEND...WITH LIKELY POPS
SATURDAY DURING THE DIURNAL PERIOD...AND HIGH CHANCE FOR SUNDAY.
AFTER IT IS MORE CERTAIN WHERE THE TROUGH WILL CLOSE OFF ON
SUNDAY...LIKELY POPS MAY ALSO BE NEEDED THERE...AS A SSW-TO-NNE
AXIS OF MOISTURE AND FORCING WILL BE PRESENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
VERY UNSETTLED PATTERN TO DEVELOP AS AMPLIFIED LONGWAVE FLOW SETS
UP AND PERSISTS THROUGH THIS PERIOD. COULDNT REALLY FIND A DECENT
PERIOD TO INDICATE PROLONGED DRY CONDITIONS...WITH LONGWAVE TROUGH
DEVELOPING/DEEPENING SW TO NE ALONG AND WEST OF THE APPALACHIAN
CHAIN. TWO MASSIVE RIDGES...ONE OVER THE WEST CONUS AND ONE OVER
THE ATLANTIC...RETROGRADE AND AMPLIFY THROUGH THE PERIOD WITH THE
WEAKNESS/TROUGH BETWEEN THE TWO ALSO GAINING AMPLITUDE. NEGATIVE
HEIGHT ANOMALIES ARE SIGNIFICANT AS THE TROUGH DEEPENS ESPECIALLY
TO THE SOUTH OF THE OHIO VALLEY. SUCH A DEEP TROUGH IN THE HEART
OF SUMMER MEANS THAT DAILY FLAREUPS OF CONVECTION ARE LIKELY...AND
WILL BE ESPECIALLY LIKELY TIED TO WEAK WAVES MOVING THROUGH THE
NWLY FLOW UNDERNEATH THE TROUGH EARLY IN THE PERIOD...AND IN THE
SLY FLOW AHEAD OF THE TROUGH LATE IN THE PERIOD AS THE TROUGH AXIS
DRIFTS TO THE WEST. LACK OF SCOURING OF THE LOW LEVEL MOISTURE
FIELD MEANS THERE WILL BE PLENTY OF MOISTURE AND MARGINAL INSTBY
FOR DAILY ROUNDS OF SCT STORMS TIED TO THE DIURNAL HEATING CYCLE.
WAVES TO KEY ON /AT LEAST IN THE SHORT TERM/ ARRIVE BOTH FRIDAY
AND SATURDAY SO THESE DAYS HAVE RELATIVELY HIGHER RAIN
CHANCES...BUT THERE WILL LIKELY BE MANY MORE OF THESE WAVES INTO
EARLY NEXT WEEK. TEMPERATURES...WHILE THEY WILL BE A BIT BELOW
NORMAL...WON/T BE TOO COOL GIVEN THE CORE OF THE 850MB TEMP/500MB
HEIGHT ANOMALIES QUICKLY DIG/RETROGRADE SOUTH AND WEST OF THE
AREA. CERTAINLY NO 90S THE FORECAST...BUT A LONGER OF PERIOD OF
UPPER 70S TO MID 80S AND RATHER DAMP/MUGGY CONDITIONS IS IN THE
OFFING.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
WEAK LOW PRESSURE AND WEAK COLD FRONT WILL SLOWLY PUSH EAST
THROUGH OUR REGION THIS MORNING. SOME FORCING IN THE UPPER LEVELS
ON THE BACK SIDE OF THE WEAK LOW WILL CONTINUE THE THREAT FOR
SHOWERS/ISOLATED THUNDERSTORMS NEAR THE NRN TAF SITES THROUGH 12Z.
BIGGEST CONCERN THIS MORNING IS THE POTENTIAL FOR IFR CIGS. WITH
ABUNDANT LOW LEVEL MOISTURE REMAINING ACROSS THE AREA...CIGS BELOW
1 KFT WERE ALREADY FORMING. BELIEVE THESE CIGS SHOULD SOLIDIFY
INTO AN OVC DECK AS MID/UPPER LEVEL DEBRIS CLOUDS SHIFT EAST
TOWARD SUNRISE WHICH WILL ALLOW FOR BETTER SATURATION. HAVE KEPT
VSBYS IN THE MVFR RANGE...BUT SHOULD ENOUGH HIGHER CLOUDS THIN AND
SHIFT TO THE EAST BEFORE SUNRISE...THESE MAY LOW TO IFR AS WELL SO
WILL CONTINUE TO MONITOR.
FOR THE DAY PERIOD...GREAT LAKES AND OHIO VALLEY REGION WILL
REMAIN IN A NORTHWEST FLOW ALOFT...ALLOWING OCCASIONAL DISTURBANCES
TO DROP INTO THE REGION THIS AFTERNOON AND OVERNIGHT. AS IFR CIGS
RISE TO VFR BY EARLY/MID AFTERNOON...THE AIRMASS SHOULD DESTABILIZE
FOR SOME SHOWER/THUNDERSTORM DEVELOPMENT. SOME MODELS SUGGEST THAT
A SURFACE TROF AXIS MAY PROVIDE SOME LOW LEVEL FORCING AS WELL.
THINK COVERAGE WILL BE IN THE 30 TO 40 PERCENT RANGE AND GIVEN
THAT IT MAY BE DISORGANIZED...HAVE JUST USED THE VCTS/CB AT THE TAF
SITES FROM 19Z TO 00Z.
FOR THE OVERNIGHT...CANNOT RULE OUR SOME LINGERING SHOWER/THUNDERSTORM
ACTIVITY GIVEN THE SYNOPTIC PATTERN...BUT DID NOT WANT TO HOLD
ONTO VCTS/CB FOR MANY HOURS...SO WILL WAIT FOR LATER TAF ISSUANCES TO
SEE IF THIS NEEDS TO CHANGE.
OUTLOOK...THUNDERSTORMS POSSIBLE THROUGH MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...BINAU
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1242 PM CDT THU JUN 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT THU JUN 27 2013
CURRENTLY SEEING SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP ACROSS
SOUTH CENTRAL AND SOUTHEAST SOUTH DAKOTA. THESE APPEAR TO BE BASED
ALONG AN AREA OF CONVERGENCE WAY UP AT 600 MB. THUS PROBABLY NOT
MUCH IN THE WAY OF RAIN REACHING THE GROUND...ALTHOUGH A FEW
HUNDREDTHS OF AN INCH ARE POSSIBLE. CAPE ONLY AROUND 100-200
J/KG...THUS NOT EXPECTING THESE TO INTENSIFY MUCH...WITH JUST
PERIODIC LIGHTNING STRIKES. MAY SEE ACTION INTENSIFY MORE TOWARDS
THE MISSOURI RIVER CLOSER TO 10Z. AS THE LOW LEVEL JET CONTINUES TO
INCREASE THIS REGION WILL BE IN A PRETTY GOOD AREA OF CONVERGENCE IN
THE 700 TO 800 MB LAYER. BEING LOWER BASED THESE SHOWERS WILL HAVE A
BIT MORE CAPE TO WORK WITH AND HAVE A BETTER CHANCE OF PRODUCING A
PERIOD OF STEADY RAINFALL. HRRR SEEMS TO BE HANDLING THINGS PRETTY
WELL...AND ALSO SUGGESTS COVERAGE AND INTENSITY OF THE STORMS SHOULD
INCREASE AFTER 10Z IN THE MISSOURI RIVER CORRIDOR FROM BON HOMME
COUNTY SOUTHEAST INTO PORTIONS OF NORTHWEST IOWA AND NORTHEAST
NEBRASKA. CAPE WILL REMAIN TOO LOW FOR ANY SEVERE THREAT...BUT AN
INCREASE IN LIGHTNING ACTIVITY AND BRIEF HEAVY RAIN SEEM PROBABLE.
THIS ACTIVITY SHOULD DISSIPATE AND PUSH SOUTHEAST OF OUR CWA BY
18Z...GIVING WAY TO INCREASING SUNSHINE. HIGHS WILL BE PRETTY
SIMILAR TO YESTERDAY...MAYBE A DEGREE OR TWO COOLER IN
SPOTS...ESPECIALLY IF CLOUD CLOVER HANGS AROUND A BIT LONGER. BUT
OVERALL...AN ABOVE NORMAL TEMPERATURE DAY WITH HIGHS IN THE MID 80S
TO AROUND 90 EXPECTED. HUMIDITY LEVELS WILL ALSO BE PRETTY SIMILAR
TO YESTERDAY...MAYBE A TOUCH LOWER BY AFTERNOON. WILL BE A BIT ON
THE BREEZY SIDE BY AFTERNOON...ESPECIALLY ACROSS THE NORTHEAST HALF
OF THE AREA...WITH WINDS GUSTING INTO THE 20 TO 30 MPH RANGE OUT OF
THE NORTHWEST. EXPECTING CLEAR SKIES TONIGHT WITH A LIGHT
NORTHWESTERLY BREEZE. LOWS SHOULD RUN A COUPLE DEGREES ABOVE
AVERAGE...ABOUT 60 TO 65 ACROSS THE AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 318 AM CDT THU JUN 27 2013
FRIDAY LOOKS DRY...WARM AND WINDY WITH NORTHWEST WINDS AVERAGING
ABOUT 20 TO 30 MPH IN THE EASTERN CWA. OTHERWISE EXPECTING HIGHS IN
THE 80S.
SATURDAY WILL SEE COOLER AIR CONTINUE TO WRAP INTO THE REGION AND
SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE DURING PEAK
HEATING. SOUNDING ANALYSIS SUGGESTS ONLY SKINNY CAPE...AND NOT MUCH
OF IT...AVAILABLE FOR UPDRAFT STRENGTH SO NOT PLANNING ON SEVERE.
LOOKS A BIT CAPPED IN THE WEST AS WELL SO WILL HAVE POPS MAINLY FROM
INTERSTATE 29 EAST. WITH CLOUDS COMING IN LOWERED HIGHS A
LITTLE...ESPECIALLY IN THE EAST WHERE 70 TO 75 WILL LIKELY BE THE
MAX WHILE CENTRAL SOUTH DAKOTA COULD REACH 80.
ANY CHANCE FOR SHOWERS SHOULD QUICKLY DIMINISH WITH PEAK HEATING SO
NOT PLANNING ON ANYTHING IN THE EVENING. A GRADUAL DECREASE IN
CLOUDS AND WIND WILL ALSO ALLOW FOR A COOL OVERNIGHT
LOW...GENERALLY IN THE MID 50S.
FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME...THE VARIOUS MODELS
CONTINUE TO CONVERGE AND A COOL AND MOSTLY DRY WEATHER PATTERN.
MODEL TRENDS FOR THE THIRD DAY ION A ROW PUSH THE RIDGE OVER THE
ROCKIES EVEN FARTHER WEST WHILE A TROUGH OF LOW PRESSURE AND
ASSOCIATED COOLER THERMAL FIELD SETTLE INTO THE PLAINS
STATES...WHICH JUST A COUPLE OF DAYS AGO LOOKED LIKE WOULD BE OVER
THE MIDWEST WITH THE PLAINS IN MORE OF A DRY MIXY PATTERN ON THE
EDGE OF AN UPPER LEVEL RIDGE. OVERALL SUSPECT THAT HIGHS WILL BE IN
THE 70S AND LOWS WILL BE IN THE 50S. PLEASANT WEATHER BUT A BIT ON
THE COOL SIDE FOR THOSE LOOKING AT LAKE AND SWIMMING POOL
ACTIVITIES. ONE PERIOD WITH THE POTENTIAL TO BE THE COOLEST AND
POSSIBLY SEE SOME RAIN SHOWERS WILL BE WEDNESDAY WHERE BOTH THE GFS
AND ECMWF SWING SOME UPPER LEVEL SUPPORT SOUTHWARD WITH INCREASING
MID AND UPPER LEVEL MOISTURE. IF IT WERE TO CLOUD UP QUICKLY ON
WEDNESDAY AND RAIN HIGH TEMPERATURES MAY BARELY CREEP INTO THE 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1242 PM CDT THU JUN 27 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS COULD GET A LITTLE
GUSTY OUT OF THE NORTHWEST THIS AFTERNOON AS SURFACE TEMPERATURES
WARM ENOUGH TO ALLOW FOR DEEPER MIXING. ANY GUSTS WILL GENERALLY BE
LESS THAN 20KT...AND SHOULD SUBSIDE QUICKLY BETWEEN 00Z-01Z THIS
EVENING. STRONGER GUSTS IN THE 20-30KT RANGE EXPECTED TO DEVELOP BY
MID MORNING FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
626 AM CDT THU JUN 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT THU JUN 27 2013
CURRENTLY SEEING SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP ACROSS
SOUTH CENTRAL AND SOUTHEAST SOUTH DAKOTA. THESE APPEAR TO BE BASED
ALONG AN AREA OF CONVERGENCE WAY UP AT 600 MB. THUS PROBABLY NOT
MUCH IN THE WAY OF RAIN REACHING THE GROUND...ALTHOUGH A FEW
HUNDREDTHS OF AN INCH ARE POSSIBLE. CAPE ONLY AROUND 100-200
J/KG...THUS NOT EXPECTING THESE TO INTENSIFY MUCH...WITH JUST
PERIODIC LIGHTNING STRIKES. MAY SEE ACTION INTENSIFY MORE TOWARDS
THE MISSOURI RIVER CLOSER TO 10Z. AS THE LOW LEVEL JET CONTINUES TO
INCREASE THIS REGION WILL BE IN A PRETTY GOOD AREA OF CONVERGENCE IN
THE 700 TO 800 MB LAYER. BEING LOWER BASED THESE SHOWERS WILL HAVE A
BIT MORE CAPE TO WORK WITH AND HAVE A BETTER CHANCE OF PRODUCING A
PERIOD OF STEADY RAINFALL. HRRR SEEMS TO BE HANDLING THINGS PRETTY
WELL...AND ALSO SUGGESTS COVERAGE AND INTENSITY OF THE STORMS SHOULD
INCREASE AFTER 10Z IN THE MISSOURI RIVER CORRIDOR FROM BON HOMME
COUNTY SOUTHEAST INTO PORTIONS OF NORTHWEST IOWA AND NORTHEAST
NEBRASKA. CAPE WILL REMAIN TOO LOW FOR ANY SEVERE THREAT...BUT AN
INCREASE IN LIGHTNING ACTIVITY AND BRIEF HEAVY RAIN SEEM PROBABLE.
THIS ACTIVITY SHOULD DISSIPATE AND PUSH SOUTHEAST OF OUR CWA BY
18Z...GIVING WAY TO INCREASING SUNSHINE. HIGHS WILL BE PRETTY
SIMILAR TO YESTERDAY...MAYBE A DEGREE OR TWO COOLER IN
SPOTS...ESPECIALLY IF CLOUD CLOVER HANGS AROUND A BIT LONGER. BUT
OVERALL...AN ABOVE NORMAL TEMPERATURE DAY WITH HIGHS IN THE MID 80S
TO AROUND 90 EXPECTED. HUMIDITY LEVELS WILL ALSO BE PRETTY SIMILAR
TO YESTERDAY...MAYBE A TOUCH LOWER BY AFTERNOON. WILL BE A BIT ON
THE BREEZY SIDE BY AFTERNOON...ESPECIALLY ACROSS THE NORTHEAST HALF
OF THE AREA...WITH WINDS GUSTING INTO THE 20 TO 30 MPH RANGE OUT OF
THE NORTHWEST. EXPECTING CLEAR SKIES TONIGHT WITH A LIGHT
NORTHWESTERLY BREEZE. LOWS SHOULD RUN A COUPLE DEGREES ABOVE
AVERAGE...ABOUT 60 TO 65 ACROSS THE AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 318 AM CDT THU JUN 27 2013
FRIDAY LOOKS DRY...WARM AND WINDY WITH NORTHWEST WINDS AVERAGING
ABOUT 20 TO 30 MPH IN THE EASTERN CWA. OTHERWISE EXPECTING HIGHS IN
THE 80S.
SATURDAY WILL SEE COOLER AIR CONTINUE TO WRAP INTO THE REGION AND
SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE DURING PEAK
HEATING. SOUNDING ANALYSIS SUGGESTS ONLY SKINNY CAPE...AND NOT MUCH
OF IT...AVAILABLE FOR UPDRAFT STRENGTH SO NOT PLANNING ON SEVERE.
LOOKS A BIT CAPPED IN THE WEST AS WELL SO WILL HAVE POPS MAINLY FROM
INTERSTATE 29 EAST. WITH CLOUDS COMING IN LOWERED HIGHS A
LITTLE...ESPECIALLY IN THE EAST WHERE 70 TO 75 WILL LIKELY BE THE
MAX WHILE CENTRAL SOUTH DAKOTA COULD REACH 80.
ANY CHANCE FOR SHOWERS SHOULD QUICKLY DIMINISH WITH PEAK HEATING SO
NOT PLANNING ON ANYTHING IN THE EVENING. A GRADUAL DECREASE IN
CLOUDS AND WIND WILL ALSO ALLOW FOR A COOL OVERNIGHT
LOW...GENERALLY IN THE MID 50S.
FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME...THE VARIOUS MODELS
CONTINUE TO CONVERGE AND A COOL AND MOSTLY DRY WEATHER PATTERN.
MODEL TRENDS FOR THE THIRD DAY ION A ROW PUSH THE RIDGE OVER THE
ROCKIES EVEN FARTHER WEST WHILE A TROUGH OF LOW PRESSURE AND
ASSOCIATED COOLER THERMAL FIELD SETTLE INTO THE PLAINS
STATES...WHICH JUST A COUPLE OF DAYS AGO LOOKED LIKE WOULD BE OVER
THE MIDWEST WITH THE PLAINS IN MORE OF A DRY MIXY PATTERN ON THE
EDGE OF AN UPPER LEVEL RIDGE. OVERALL SUSPECT THAT HIGHS WILL BE IN
THE 70S AND LOWS WILL BE IN THE 50S. PLEASANT WEATHER BUT A BIT ON
THE COOL SIDE FOR THOSE LOOKING AT LAKE AND SWIMMING POOL
ACTIVITIES. ONE PERIOD WITH THE POTENTIAL TO BE THE COOLEST AND
POSSIBLY SEE SOME RAIN SHOWERS WILL BE WEDNESDAY WHERE BOTH THE GFS
AND ECMWF SWING SOME UPPER LEVEL SUPPORT SOUTHWARD WITH INCREASING
MID AND UPPER LEVEL MOISTURE. IF IT WERE TO CLOUD UP QUICKLY ON
WEDNESDAY AND RAIN HIGH TEMPERATURES MAY BARELY CREEP INTO THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 621 AM CDT THU JUN 27 2013
MAINLY VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. SEEING
SCATTERED SHOWERS AND THUNDERSTORMS THIS MORNING...MAINLY ALONG AND
SOUTH OF INTERSTATE 90. KSUX HAS THE BEST CHANCE OF SEEING SOME
LIGHTNING THIS MORNING...WITH KFSD JUST SEEING A FEW SHOWERS.
CONDITIONS WILL MAINLY STAY VFR EVEN IN THE RAIN...ALTHOUGH SOME
BRIEF REDUCTIONS TO MVFR ARE POSSIBLE IN THE HEAVIER STORMS. EXPECT
THE ACTIVITY TO DISSIPATE BY THIS AFTERNOON...GIVING WAY TO MOSTLY
SUNNY SKIES AND NORTHWESTERLY BREEZE GUSTING UP TO AROUND 20 KTS AT
KHON AND KFSD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
319 AM CDT THU JUN 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT THU JUN 27 2013
CURRENTLY SEEING SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP ACROSS
SOUTH CENTRAL AND SOUTHEAST SOUTH DAKOTA. THESE APPEAR TO BE BASED
ALONG AN AREA OF CONVERGENCE WAY UP AT 600 MB. THUS PROBABLY NOT
MUCH IN THE WAY OF RAIN REACHING THE GROUND...ALTHOUGH A FEW
HUNDRETHS OF AN INCH ARE POSSIBLE. CAPE ONLY AROUND 100-200
J/KG...THUS NOT EXPECTING THESE TO INTENSIFY MUCH...WITH JUST
PERIODIC LIGHTNING STRIKES. MAY SEE ACTION INTENSIFY MORE TOWARDS
THE MISSOURI RIVER CLOSER TO 10Z. AS THE LOW LEVEL JET CONTINUES TO
INCREASE THIS REGION WILL BE IN A PRETTY GOOD AREA OF CONVERGENCE IN
THE 700 TO 800 MB LAYER. BEING LOWER BASED THESE SHOWERS WILL HAVE A
BIT MORE CAPE TO WORK WITH AND HAVE A BETTER CHANCE OF PRODUCING A
PERIOD OF STEADY RAINFALL. HRRR SEEMS TO BE HANDLING THINGS PRETTY
WELL...AND ALSO SUGGESTS COVERAGE AND INTENSITY OF THE STORMS SHOULD
INCREASE AFTER 10Z IN THE MISSOURI RIVER CORRIDOR FROM BON HOMME
COUNTY SOUTHEAST INTO PORTIONS OF NORTHWEST IOWA AND NORTHEAST
NEBRASKA. CAPE WILL REMAIN TOO LOW FOR ANY SEVERE THREAT...BUT AN
INCREASE IN LIGHTNING ACTIVITY AND BRIEF HEAVY RAIN SEEM PROBABLE.
THIS ACTIVITY SHOULD DISSIPATE AND PUSH SOUTHEAST OF OUR CWA BY
18Z...GIVING WAY TO INCREASING SUNSHINE. HIGHS WILL BE PRETTY
SIMILAR TO YESTERDAY...MAYBE A DEGREE OR TWO COOLER IN
SPOTS...ESPECIALLY IF CLOUD CLOVER HANGS AROUND A BIT LONGER. BUT
OVERALL...AN ABOVE NORMAL TEMPERATURE DAY WITH HIGHS IN THE MID 80S
TO AROUND 90 EXPECTED. HUMIDITY LEVELS WILL ALSO BE PRETTY SIMILAR
TO YESTERDAY...MAYBE A TOUCH LOWER BY AFTERNOON. WILL BE A BIT ON
THE BREEZY SIDE BY AFTERNOON...ESPECIALLY ACROSS THE NORTHEAST HALF
OF THE AREA...WITH WINDS GUSTING INTO THE 20 TO 30 MPH RANGE OUT OF
THE NORTHWEST. EXPECTING CLEAR SKIES TONIGHT WITH A LIGHT
NORTHWESTERLY BREEZE. LOWS SHOULD RUN A COUPLE DEGREES ABOVE
AVERAGE...ABOUT 60 TO 65 ACROSS THE AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 318 AM CDT THU JUN 27 2013
FRIDAY LOOKS DRY...WARM AND WINDY WITH NORTHWEST WINDS AVERAGING
ABOUT 20 TO 30 MPH IN THE EASTERN CWA. OTHERWISE EXPECTING HIGHS IN
THE 80S.
SATURDAY WILL SEE COOLER AIR CONTINUE TO WRAP INTO THE REGION AND
SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE DURING PEAK
HEATING. SOUNDING ANALYSIS SUGGESTS ONLY SKINNY CAPE...AND NOT MUCH
OF IT...AVAILABLE FOR UPDRAFT STRENGTH SO NOT PLANNING ON SEVERE.
LOOKS A BIT CAPPED IN THE WEST AS WELL SO WILL HAVE POPS MAINLY FROM
INTERSTATE 29 EAST. WITH CLOUDS COMING IN LOWERED HIGHS A
LITTLE...ESPECIALLY IN THE EAST WHERE 70 TO 75 WILL LIKELY BE THE
MAX WHILE CENTRAL SOUTH DAKOTA COULD REACH 80.
ANY CHANCE FOR SHOWERS SHOULD QUICKLY DIMINISH WITH PEAK HEATING SO
NOT PLANNING ON ANYTHING IN THE EVENING. A GRADUAL DECREASE IN
CLOUDS AND WIND WILL ALSO ALLOW FOR A COOL OVERNIGHT
LOW...GENERALLY IN THE MID 50S.
FOR THE SUNDAY THROUGH WEDNESDAY TIME FRAME...THE VARIOUS MODELS
CONTINUE TO CONVERGE AND A COOL AND MOSTLY DRY WEATHER PATTERN.
MODEL TRENDS FOR THE THIRD DAY ION A ROW PUSH THE RIDGE OVER THE
ROCKIES EVEN FARTHER WEST WHILE A TROUGH OF LOW PRESSURE AND
ASSOCIATED COOLER THERMAL FIELD SETTLE INTO THE PLAINS
STATES...WHICH JUST A COUPLE OF DAYS AGO LOOKED LIKE WOULD BE OVER
THE MIDWEST WITH THE PLAINS IN MORE OF A DRY MIXY PATTERN ON THE
EDGE OF AN UPPER LEVEL RIDGE. OVERALL SUSPECT THAT HIGHS WILL BE IN
THE 70S AND LOWS WILL BE IN THE 50S. PLEASANT WEATHER BUT A BIT ON
THE COOL SIDE FOR THOSE LOOKING AT LAKE AND SWIMMING POOL
ACTIVITIES. ONE PERIOD WITH THE POTENTIAL TO BE THE COOLEST AND
POSSIBLY SEE SOME RAIN SHOWERS WILL BE WEDNESDAY WHERE BOTH THE GFS
AND ECMWF SWING SOME UPPER LEVEL SUPPORT SOUTHWARD WITH INCREASING
MID AND UPPER LEVEL MOISTURE. IF IT WERE TO CLOUD UP QUICKLY ON
WEDNESDAY AND RAIN HIGH TEMPERATURES MAY BARELY CREEP INTO THE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1026 PM CDT WED JUN 26 2013
PRIMARILY VFR CONDITIONS THROUGH THE TAF PERIOD...ALTHOUGH
CONVECTION MAY DEVELOP THROUGH THE MISSOURI RIVER CORRIDOR AFTER
08Z...LINGERING INTO MID THURSDAY MORNING. KSUX IS ON THE EDGE OF
THE BETTER CONVECTION CHANCES...SO DID NOT INCLUDE IN THE TAF AT
THIS TIME. OTHERWISE...LIGHT AND VARIABLE WINDS THROUGH THE MID
NIGHT TIME HOURS...THEN TRANSITIONING TO NORTHWESTERLY AND PICKING
UP A BIT TOWARD THURSDAY MORNING WITH THE PASSAGE OF A BOUNDARY.
OTHER THAN THE POSSIBILITY OF LINGERING CONVECTION IN THE LOWER
MISSOURI RIVER CORRIDOR THROUGH AROUND 15Z...THE REMAINDER OF
THURSDAY WILL HAVE A FEW MID CLOUDS WITH NORTHWESTERLY WINDS
AVERAGING IN THE 10 TO 15 KT RANGE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
212 AM CDT THU JUN 27 2013
.MESOSCALE UPDATE...
LATEST H-TRIPLE-R 3KM RUN CONTINUES TO WEAKEN AND SINK LEADING
EDGE OF CONVECTION SOUTHWARD INTO ALABAMA BY 08Z. EXPECT SOME
ISOLATED TO SCATTERED CONVECTION WILL REMAIN ACROSS MIDDLE
TENNESSEE THROUGH THE REMAINDER OF THE OVERNIGHT HOURS. NOT
ANTICIPATING HAVING TO ISSUE WARNINGS BUT WILL CONTINUE TO
MONITOR.
BOYD
&&
.PREV DISCUSSION... /ISSUED 1233 AM CDT THU JUN 27 2013/
MESOSCALE UPDATE...
TWO SEPERATE MESO CONVECTIVE SYSTEMS DROPPING DOWN INTO THE
NORTHERN PART OF THE TENNESSEE VALLEY AT THIS TIME WITH THE STRONGEST
CONVECTION IN MID STATE CURRENTLY OVER WESTERN AREAS AND
SPECIFICALLY IN HUMPHREYS COUNTY AT 0530Z. LATEST RUC RUN SHOWS
850 MBAR TROUGH DOWN THROUGH MIDDLE TENNESSEE JUST EAST OF
INTERSTATE 65 SEPERATING THE TWO MCS`S.
BOYD
PREV DISCUSSION... /ISSUED 1207 AM CDT THU JUN 27 2013/
AVIATION 06Z DISCUSSION...
SHORTWAVE WILL CONTINUE TO MOVE ACROSS THE MID STATE OVERNIGHT. AN
AREA OF SHOWERS AND TSTMS WILL MOVE ACROSS NORTHERN AREAS AND TO
THE SOUTH OF THE TAF SITES BY 10Z. TSTM REDEVELOPMENT WILL AGAIN
BE POSSIBLE ACROSS EASTERN PORTIONS OF THE MID STATE AFT 18Z ON THU.
HOWEVER...LESS COVERAGE CAN BE EXPECTED AS OVERALL...THE AIRMASS
WILL BE DRIER.
PREV DISCUSSION... /ISSUED 847 PM CDT WED JUN 26 2013/
MESOSCALE UPDATE...A COUPLE OF LINES OF STORMS BEING WATCHED. THE
FIRST COMING DOWN INTO WEST KY APPEARS STRONG TO MARGINALLY SEVERE
WITH 50-55 MPH WINDS EXPECTED BY THE PADUCAH OFFICE. THIS LINE OF
STORMS SHOULD REACH OUR NORTHWEST COUNTIES ABOUT 10 PM. ANOTHER
LINE OF STORMS ROUGHLY FROM EVANSVILLE TO LOUISVILLE LOOKS SEVERE.
THIS LINE WILL DROP DOWN TO OUR NORTH CENTRAL AND NORTHEAST
COUNTIES AROUND MIDNIGHT...AND MAY STILL BE PRODUCING SEVERE
WINDS.
THE EVENING SOUNDING SHOWS CAPES JUST OVER 2 KJ/KG. SHEAR AND WINDS
INDICATE CONTINUED UPDRAFT SUPPORT FOR INCOMING STORMS. SOUTHWEST
TO WEST LOW LEVEL JET SETTING UP WILL ADD SUPPORT FOR
STORMS...ESPECIALLY INTO OUR NORTHEAST COUNTIES LATE TONIGHT.
13
PREV DISCUSSION...
627 PM CDT WED JUN 26 2013
MESOSCALE UPDATE...QUIET EVENING SO FAR IN MID TN AS WE WATCH
CONVECTION EVOLVE A LITTLE MORE SLUGGISHLY THAN ANTICIPATED OVER
THE OHIO VALLEY. NOT A LOT OF SEVERE REPORTS UP THERE YET...MORE
HEAVY RAIN. HOWEVER...SHORT RANGE MODELS CONTINUE TO INDICATE MORE
CONVECTIVE DEVELOPMENT OVER SOUTHERN IL AND SE MO...WITH ACTIVITY
SINKING SOUTHWARD INTO MID TN AFTER 9 PM. ATMOSPHERE SHOULD BE
PLENTY UNSTABLE AS THIS ACTIVITY MOVES IN WITH CAPES STILL
AOA 2 KJ/KG. SO...OUR MAIN FOCUS FOR THE NEXT COUPLE OF HOURS
WILL BE WATCHING THE EVOLUTION OF STORMS AND POTENTIAL MCS INTO
WEST KY. ALSO...WE WILL GET NEW UPPER AIR RESULTS...WITH DATA
BEING COLLECTED AT THIS TIME.
13
PREV DISCUSSION... /ISSUED 331 PM CDT WED JUN 26 2013/
DISCUSSION...
UNSETTLED PATTERN IS EXPECTED FOR THE WEEK AHEAD WITH INCREASING H5
NORTHWEST FLOW THE NEXT FEW DAYS FOLLOWED BY A BROAD WESTWARD
DRIFTING UPPER TROUGH EARLY NEXT WEEK. OVERALL...THIS PATTERN
SHOULD CAUSE SOMEWHAT ABOVE AVERAGE CLOUD COVER AND RAIN CHANCES
WITH SLIGHTLY BELOW AVERAGE MAX TEMPS FOR THIS TIME OF YEAR.
H5 FLOW WILL BECOME MORE NORTHWESTERLY TONIGHT INTO SATURDAY AS SW
U.S. RIDGE BUILDS AND EDGES WESTWARD...WHILE BROAD TROUGH DEVELOPS
ACROSS THE GREAT LAKES. THIS OPENS THE DOOR FOR ORGANIZED STORMS
TO APPROACH FROM THE NORTHWEST...ESPECIALLY TONIGHT WITH A
POSSIBLE MCS. ALL AREAS WILL SEE AT LEAST A CHANCE FOR STORMS THIS
EVENING BUT BEST COINCIDING MOISTURE LIFT AND INSTABILITY APPEAR TO
ALIGN ACROSS THE NORTHEAST HALF OF MIDDLE TN LATE TONIGHT.
UNSTABLE AIRMASS COMBINED WITH DECENT SHEAR COULD CAUSE SOME
STRONG TO SEVERE STORMS OVERNIGHT. MORE STORMS POSSIBLE AGAIN
THURSDAY/FRIDAY AS TWO MORE WEAK S/W APPROACH IN THE NW FLOW.
THE NW FLOW PATTERN WILL ALSO ALLOW A COUPLE WEAK FRONTS/OUTFLOWS
TO MOVE INTO MIDDLE TN THURSDAY AND FRIDAY. MODELS AGREE ON A
BETTER SURGE ARRIVING SATURDAY...WITH THE FRONT MOVING THROUGH
ALL OF MIDDLE TN THEN STALLING EAST OF OUR REGION ON SUNDAY. THIS
SHOULD CAUSE MAX TEMPS TO BE A FEW DEGREES BELOW AVERAGE THIS
WEEKEND.
FOR SUNDAY NIGHT THROUGH WEDNESDAY...THE GREAT LAKES H5 LOW
GRADUALLY SLIPS SOUTHWESTWARD TO THE OHIO VALLEY BY LATE
SUNDAY...THEN FURTHER WEST TO THE MIDDLE OF THE U.S. BY NEXT
WEDNESDAY. AT THE SURFACE...THE STALLED FRONT TO OUR SOUTHEAST
WILL GRADUALLY SPREAD BACK TO THE WEST. EXPECT FRONT TO BE NEAR
MIDDLE TN ON MONDAY THEN MOVE FURTHER WESTWARD TUE/WED. MEAN
HUMIDITIES WILL INCREASE MONDAY THROUGH WEDNESDAY AS FLOW BECOMES
MORE SOUTHERLY AT ALL LEVELS. THUS...EXPECT ABOVE AVERAGE CLOUD
COVER AND CHANCES FOR AFTERNOON AND EVENING STORMS...WITH DAYTIME
MAX TEMPS CONTINUING TO BE A BIT LOWER THAN AVERAGE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1233 AM CDT THU JUN 27 2013
.MESOSCALE UPDATE...
TWO SEPERATE MESO CONVECTIVE SYSTEMS DROPPING DOWN INTO THE
NORTHERN PART OF THE TENNESSEE VALLEY AT THIS TIME WITH THE STRONGEST
CONVECTION IN MID STATE CURRENTLY OVER WESTERN AREAS AND
SPECIFICALLY IN HUMPHREYS COUNTY AT 0530Z. LATEST RUC RUN SHOWS
850 MBAR TROUGH DOWN THROUGH MIDDLE TENNESSEE JUST EAST OF
INTERSTATE 65 SEPERATING THE TWO MCS`S.
BOYD
&&
.PREV DISCUSSION... /ISSUED 1207 AM CDT THU JUN 27 2013/
AVIATION 06Z DISCUSSION...
SHORTWAVE WILL CONTINUE TO MOVE ACROSS THE MID STATE OVERNIGHT. AN
AREA OF SHOWERS AND TSTMS WILL MOVE ACROSS NORTHERN AREAS AND TO
THE SOUTH OF THE TAF SITES BY 10Z. TSTM REDEVELOPMENT WILL AGAIN
BE POSSIBLE ACROSS EASTERN PORTIONS OF THE MID STATE AFT 18Z ON THU.
HOWEVER...LESS COVERAGE CAN BE EXPECTED AS OVERALL...THE AIRMASS
WILL BE DRIER.
PREV DISCUSSION... /ISSUED 847 PM CDT WED JUN 26 2013/
MESOSCALE UPDATE...A COUPLE OF LINES OF STORMS BEING WATCHED. THE
FIRST COMING DOWN INTO WEST KY APPEARS STRONG TO MARGINALLY SEVERE
WITH 50-55 MPH WINDS EXPECTED BY THE PADUCAH OFFICE. THIS LINE OF
STORMS SHOULD REACH OUR NORTHWEST COUNTIES ABOUT 10 PM. ANOTHER
LINE OF STORMS ROUGHLY FROM EVANSVILLE TO LOUISVILLE LOOKS SEVERE.
THIS LINE WILL DROP DOWN TO OUR NORTH CENTRAL AND NORTHEAST
COUNTIES AROUND MIDNIGHT...AND MAY STILL BE PRODUCING SEVERE
WINDS.
THE EVENING SOUNDING SHOWS CAPES JUST OVER 2 KJ/KG. SHEAR AND WINDS
INDICATE CONTINUED UPDRAFT SUPPORT FOR INCOMING STORMS. SOUTHWEST
TO WEST LOW LEVEL JET SETTING UP WILL ADD SUPPORT FOR
STORMS...ESPECIALLY INTO OUR NORTHEAST COUNTIES LATE TONIGHT.
13
PREV DISCUSSION...
627 PM CDT WED JUN 26 2013
MESOSCALE UPDATE...QUIET EVENING SO FAR IN MID TN AS WE WATCH
CONVECTION EVOLVE A LITTLE MORE SLUGGISHLY THAN ANTICIPATED OVER
THE OHIO VALLEY. NOT A LOT OF SEVERE REPORTS UP THERE YET...MORE
HEAVY RAIN. HOWEVER...SHORT RANGE MODELS CONTINUE TO INDICATE MORE
CONVECTIVE DEVELOPMENT OVER SOUTHERN IL AND SE MO...WITH ACTIVITY
SINKING SOUTHWARD INTO MID TN AFTER 9 PM. ATMOSPHERE SHOULD BE
PLENTY UNSTABLE AS THIS ACTIVITY MOVES IN WITH CAPES STILL
AOA 2 KJ/KG. SO...OUR MAIN FOCUS FOR THE NEXT COUPLE OF HOURS
WILL BE WATCHING THE EVOLUTION OF STORMS AND POTENTIAL MCS INTO
WEST KY. ALSO...WE WILL GET NEW UPPER AIR RESULTS...WITH DATA
BEING COLLECTED AT THIS TIME.
13
PREV DISCUSSION... /ISSUED 331 PM CDT WED JUN 26 2013/
DISCUSSION...
UNSETTLED PATTERN IS EXPECTED FOR THE WEEK AHEAD WITH INCREASING H5
NORTHWEST FLOW THE NEXT FEW DAYS FOLLOWED BY A BROAD WESTWARD
DRIFTING UPPER TROUGH EARLY NEXT WEEK. OVERALL...THIS PATTERN
SHOULD CAUSE SOMEWHAT ABOVE AVERAGE CLOUD COVER AND RAIN CHANCES
WITH SLIGHTLY BELOW AVERAGE MAX TEMPS FOR THIS TIME OF YEAR.
H5 FLOW WILL BECOME MORE NORTHWESTERLY TONIGHT INTO SATURDAY AS SW
U.S. RIDGE BUILDS AND EDGES WESTWARD...WHILE BROAD TROUGH DEVELOPS
ACROSS THE GREAT LAKES. THIS OPENS THE DOOR FOR ORGANIZED STORMS
TO APPROACH FROM THE NORTHWEST...ESPECIALLY TONIGHT WITH A
POSSIBLE MCS. ALL AREAS WILL SEE AT LEAST A CHANCE FOR STORMS THIS
EVENING BUT BEST COINCIDING MOISTURE LIFT AND INSTABILITY APPEAR TO
ALIGN ACROSS THE NORTHEAST HALF OF MIDDLE TN LATE TONIGHT.
UNSTABLE AIRMASS COMBINED WITH DECENT SHEAR COULD CAUSE SOME
STRONG TO SEVERE STORMS OVERNIGHT. MORE STORMS POSSIBLE AGAIN
THURSDAY/FRIDAY AS TWO MORE WEAK S/W APPROACH IN THE NW FLOW.
THE NW FLOW PATTERN WILL ALSO ALLOW A COUPLE WEAK FRONTS/OUTFLOWS
TO MOVE INTO MIDDLE TN THURSDAY AND FRIDAY. MODELS AGREE ON A
BETTER SURGE ARRIVING SATURDAY...WITH THE FRONT MOVING THROUGH
ALL OF MIDDLE TN THEN STALLING EAST OF OUR REGION ON SUNDAY. THIS
SHOULD CAUSE MAX TEMPS TO BE A FEW DEGREES BELOW AVERAGE THIS
WEEKEND.
FOR SUNDAY NIGHT THROUGH WEDNESDAY...THE GREAT LAKES H5 LOW
GRADUALLY SLIPS SOUTHWESTWARD TO THE OHIO VALLEY BY LATE
SUNDAY...THEN FURTHER WEST TO THE MIDDLE OF THE U.S. BY NEXT
WEDNESDAY. AT THE SURFACE...THE STALLED FRONT TO OUR SOUTHEAST
WILL GRADUALLY SPREAD BACK TO THE WEST. EXPECT FRONT TO BE NEAR
MIDDLE TN ON MONDAY THEN MOVE FURTHER WESTWARD TUE/WED. MEAN
HUMIDITIES WILL INCREASE MONDAY THROUGH WEDNESDAY AS FLOW BECOMES
MORE SOUTHERLY AT ALL LEVELS. THUS...EXPECT ABOVE AVERAGE CLOUD
COVER AND CHANCES FOR AFTERNOON AND EVENING STORMS...WITH DAYTIME
MAX TEMPS CONTINUING TO BE A BIT LOWER THAN AVERAGE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
839 PM CDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 839 PM CDT FRI JUN 28 2013
SCATTERED TO OCCASIONAL RAIN SHOWERS CONTINUE ACROSS MUCH OF THE
REGION WITH THE MAIN BAND EXTENDING ALONG A SOUTHEAST TO NORTHWEST
ORIENTED MID LEVEL SHORT WAVE TROUGH THAT RUNS FROM NORTHERN
ILLINOIS TOWARD NORTHERN MINNESOTA. THIS TROUGH WILL NOT SHIFT
MUCH TONIGHT AS A BUILDING RIDGE ACROSS THE ROCKIES WILL BLOCK ANY
MOVEMENT WEST. INSTABILITY HAS BEEN RAPIDLY DECREASING...SO EXPECT
THAT THE THUNDER CHANCES WILL GREATLY DIMINISH OVER THE NEXT FEW
HOURS. DESPITE THIS DECREASING INSTABILITY...SHOWERS HAVE BEEN
SLOW TO DIMINISH IN COVERAGE DUE TO THE MID LEVEL ASCENT PROVIDED
BY THE TROUGH TO GO ALONG WITH ANY REMNANT SURFACE BOUNDARIES LEFT
OVER BY EARLIER CONVECTION. BASED ON THIS...HAVE UPPED THE
PRECIPITATION CHANCES ACROSS SOUTHEAST MINNESOTA TO NORTHEAST IOWA
WHERE IT LOOKS LIKE THIS LIFT WILL SIT OVER TONIGHT...BUT DID
CONTINUE THE DIMINISHING COVERAGE TREND.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 218 PM CDT FRI JUN 28 2013
WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWS A CLOSED LOW NEAR THE
LAKE HURON/EERIE REGION WITH A TROUGH EXTENDING WESTWARD ACROSS
LOWER MI INTO NORTHERN WI/MN. RAP ANALYZING SEVERAL EMBEDDED
POSITIVE VORTICITY MAXIMA WITHIN THIS TROUGH...ADVECTING SOUTHWARD
ACROSS THE AREA. THIS TROUGH/VORTICITY...COMBINED WITH FAIRLY STEEP LOWER
LEVEL LAPSE RATES WAS PRODUCING SCATTERED SHOWER ACTIVITY MAINLY
EAST OF THE MISSISSIPPI RIVER. OTHERWISE...AN EXTENSIVE CUMULUS
FIELD WAS NOTED ACROSS THE REGION UNDER THE COOLER CYCLONIC FLOW
ALOFT WITH SURFACE TEMPERATURES RANGING FROM THE 65-70 DEGREES
ACROSS NORTHERN WI...TO THE NEAR 80 ACROSS NORTHEAST IA/FAR
SOUTHWEST WI. IN ADDITION...BREEZY NORTHWEST WINDS MAKING IT FEEL
LIKE MORE OF AN EARLY AUTUMN DAY ACROSS THE REGION.
LOOK FOR THE MID-LEVEL TROUGH TO CONTINUE DROPPING SOUTHWARD ACROSS
THE AREA TONIGHT...PRODUCING EXTENSIVE CLOUD COVER AND SCATTERED
SHOWER ACTIVITY. LOWS OVERNIGHT EXPECTED TO DROP OFF INTO THE UPPER
50S TO THE LOWER 60S.
COOLER CYCLONIC FLOW TO CONTINUE ACROSS THE AREA ON SATURDAY.
THUS...ANOTHER DAY OF ABUNDANT CLOUD COVER AND SCATTERED SHOWERS CAN
BE EXPECTED. AN ISOLATED RUMBLE OF THUNDER MAY ALSO OCCUR AS 0-1KM
ML MUCAPE PERKS UP INTO THE 400-1000J/KG RANGE BY AFTERNOON. BAY
LATER IN THE AFTERNOON...EXPECTING MOST OF THE CONVECTION TO BE
CONFINED SOUTH MAINLY SOUTH OF I-94 AS THE MID-LEVEL TROUGH AXIS
DROPS FARTHER SOUTH INTO IA/IL AND RIDGING STARTS TO BUILD ACROSS
THE NORTH. OTHERWISE...PLAN ON TEMPERATURES TO BE A COUPLE DEGREES
COOLER THAN FRIDAY...TOPPING OFF IN THE 70-75 RANGE.
THE MID-LEVEL TROUGH WILL CONTINUE TO ROTATE SOUTH OF THE AREA
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN
PLAINS/MN. AS A RESULT...LOOK FOR A RAPID DIMINISHING OF SHOWER
ACTIVITY ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA WITH CLEARING
SKIES FROM NORTH TO SOUTH AS THE EVENING PROGRESSES. MOSTLY CLEAR
SKIES WILL THEN BE NOTED OVERNIGHT WITH TEMPERATURES COOLING INTO
THE UPPER 40S TO THE MIDDLE 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 218 PM CDT FRI JUN 28 2013
PATTERN REMAINS BASICALLY UNCHANGED FROM SUNDAY THROUGH TUESDAY
NIGHT WITH THE MID-LEVEL TROUGH AXIS EXTENDING FROM THE GREAT LAKES
TO TO THE OHIO RIVER VALLEY WHILE RIDGE OF HIGH PRESSURE CONTROLS
THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGIONS. THIS
KEEPS THE AREA DRY WITH TEMPERATURES REMAINING A FEW DEGREES BELOW
NORMAL. PLAN ON HIGHS IN THE MID/UPPER 70S WITH OVERNIGHT LOWS IN
THE 50S. IT APPEARS THE GFS/ECMWF EVENTUALLY SHOW THE MID-LEVEL
TROUGH FILLING/LIFTING NORTHEAST INTO THE EASTERN GREAT
LAKES/EASTERN ONTARIO BY FRIDAY WITH FLOW BECOMING MORE LAMINAR/HIGH
ZONAL ACROSS CANADA. SO...LOOKS LIKE A SLIGHT CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS WEDNESDAY AND THURSDAY WITH FRIDAY DRY AND
BECOMING WARMER. PLAN ON HIGHS IN THE UPPER 70S ON WEDNESDAY...
WARMING INTO THE 80-85 DEGREE RANGE BY FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 710 PM CDT FRI JUN 28 2013
OCCASIONAL SHOWERS AND A FEW THUNDERSTORMS WILL DIMINISH IN
COVERAGE ACROSS THE REGION THIS EVENING. THESE SHOWERS MAY CAUSE
SOME BRIEF VISIBILITY REDUCTIONS DOWN TO MVFR WITH ANY LIGHTNING
POTENTIAL NOT LIKELY BEYOND 1Z. THESE SHOWERS WILL LINGER THROUGH
THE OVERNIGHT HOURS...BUT THE CHANCES ARE NOT VERY HIGH THAT ONE
PARTICULAR SHOWER WOULD HIT LSE/RST...SO HAVE LEFT IT AS A
VICINITY SHOWER THROUGH THE REST OF THE PERIOD. CONDITIONS WILL
MAINLY BE VFR WITH CEILINGS STAYING BETWEEN 3-6KFT. WIND GUSTS
WILL ALSO WEAKEN THIS EVENING BEFORE PICKING BACK UP TOMORROW
MORNING WITH GUSTS IN THE 15 TO 25KT RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
710 PM CDT FRI JUN 28 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 218 PM CDT FRI JUN 28 2013
WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWS A CLOSED LOW NEAR THE
LAKE HURON/EERIE REGION WITH A TROUGH EXTENDING WESTWARD ACROSS
LOWER MI INTO NORTHERN WI/MN. RAP ANALYZING SEVERAL EMBEDDED
POSITIVE VORTICITY MAXIMA WITHIN THIS TROUGH...ADVECTING SOUTHWARD
ACROSS THE AREA. THIS TROUGH/VORTICITY...COMBINED WITH FAIRLY STEEP LOWER
LEVEL LAPSE RATES WAS PRODUCING SCATTERED SHOWER ACTIVITY MAINLY
EAST OF THE MISSISSIPPI RIVER. OTHERWISE...AN EXTENSIVE CUMULUS
FIELD WAS NOTED ACROSS THE REGION UNDER THE COOLER CYCLONIC FLOW
ALOFT WITH SURFACE TEMPERATURES RANGING FROM THE 65-70 DEGREES
ACROSS NORTHERN WI...TO THE NEAR 80 ACROSS NORTHEAST IA/FAR
SOUTHWEST WI. IN ADDITION...BREEZY NORTHWEST WINDS MAKING IT FEEL
LIKE MORE OF AN EARLY AUTUMN DAY ACROSS THE REGION.
LOOK FOR THE MID-LEVEL TROUGH TO CONTINUE DROPPING SOUTHWARD ACROSS
THE AREA TONIGHT...PRODUCING EXTENSIVE CLOUD COVER AND SCATTERED
SHOWER ACTIVITY. LOWS OVERNIGHT EXPECTED TO DROP OFF INTO THE UPPER
50S TO THE LOWER 60S.
COOLER CYCLONIC FLOW TO CONTINUE ACROSS THE AREA ON SATURDAY.
THUS...ANOTHER DAY OF ABUNDANT CLOUD COVER AND SCATTERED SHOWERS CAN
BE EXPECTED. AN ISOLATED RUMBLE OF THUNDER MAY ALSO OCCUR AS 0-1KM
ML MUCAPE PERKS UP INTO THE 400-1000J/KG RANGE BY AFTERNOON. BAY
LATER IN THE AFTERNOON...EXPECTING MOST OF THE CONVECTION TO BE
CONFINED SOUTH MAINLY SOUTH OF I-94 AS THE MID-LEVEL TROUGH AXIS
DROPS FARTHER SOUTH INTO IA/IL AND RIDGING STARTS TO BUILD ACROSS
THE NORTH. OTHERWISE...PLAN ON TEMPERATURES TO BE A COUPLE DEGREES
COOLER THAN FRIDAY...TOPPING OFF IN THE 70-75 RANGE.
THE MID-LEVEL TROUGH WILL CONTINUE TO ROTATE SOUTH OF THE AREA
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN
PLAINS/MN. AS A RESULT...LOOK FOR A RAPID DIMINISHING OF SHOWER
ACTIVITY ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA WITH CLEARING
SKIES FROM NORTH TO SOUTH AS THE EVENING PROGRESSES. MOSTLY CLEAR
SKIES WILL THEN BE NOTED OVERNIGHT WITH TEMPERATURES COOLING INTO
THE UPPER 40S TO THE MIDDLE 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 218 PM CDT FRI JUN 28 2013
PATTERN REMAINS BASICALLY UNCHANGED FROM SUNDAY THROUGH TUESDAY
NIGHT WITH THE MID-LEVEL TROUGH AXIS EXTENDING FROM THE GREAT LAKES
TO TO THE OHIO RIVER VALLEY WHILE RIDGE OF HIGH PRESSURE CONTROLS
THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGIONS. THIS
KEEPS THE AREA DRY WITH TEMPERATURES REMAINING A FEW DEGREES BELOW
NORMAL. PLAN ON HIGHS IN THE MID/UPPER 70S WITH OVERNIGHT LOWS IN
THE 50S. IT APPEARS THE GFS/ECMWF EVENTUALLY SHOW THE MID-LEVEL
TROUGH FILLING/LIFTING NORTHEAST INTO THE EASTERN GREAT
LAKES/EASTERN ONTARIO BY FRIDAY WITH FLOW BECOMING MORE LAMINAR/HIGH
ZONAL ACROSS CANADA. SO...LOOKS LIKE A SLIGHT CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS WEDNESDAY AND THURSDAY WITH FRIDAY DRY AND
BECOMING WARMER. PLAN ON HIGHS IN THE UPPER 70S ON WEDNESDAY...
WARMING INTO THE 80-85 DEGREE RANGE BY FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 710 PM CDT FRI JUN 28 2013
OCCASIONAL SHOWERS AND A FEW THUNDERSTORMS WILL DIMINISH IN
COVERAGE ACROSS THE REGION THIS EVENING. THESE SHOWERS MAY CAUSE
SOME BRIEF VISIBILITY REDUCTIONS DOWN TO MVFR WITH ANY LIGHTNING
POTENTIAL NOT LIKELY BEYOND 1Z. THESE SHOWERS WILL LINGER THROUGH
THE OVERNIGHT HOURS...BUT THE CHANCES ARE NOT VERY HIGH THAT ONE
PARTICULAR SHOWER WOULD HIT LSE/RST...SO HAVE LEFT IT AS A
VICINITY SHOWER THROUGH THE REST OF THE PERIOD. CONDITIONS WILL
MAINLY BE VFR WITH CEILINGS STAYING BETWEEN 3-6KFT. WIND GUSTS
WILL ALSO WEAKEN THIS EVENING BEFORE PICKING BACK UP TOMORROW
MORNING WITH GUSTS IN THE 15 TO 25KT RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...HALBACH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 331 PM CDT THU JUN 27 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 100KT JET
STREAK DIVING INTO THE WESTERN GREAT LAKES AS THE SOUTHWEST SUB-
TROPICAL RIDGE BUILDS NORTHWARD. VARIOUS SHORTWAVE IMPULSES FROM
SOUTHERN MANITOBA TO THE UPPER PENINSULA COMBINED WITH INCREASING
INSTABILITY AROUND 1500 J/KG ARE TRIGGERING SCATTER SHOWERS AND
THUNDERSTORMS. MANY STORMS HAVE BEEN FLIRTING WITH SEVERE
LEVELS...WHICH SHOULD CONTINUE THROUGH EARLY THIS EVENING. PRIMARY
UPPER TROUGH OVER SOUTHEAST MANITOBA WILL BE DROPPING INTO THE
REGION TOMORROW. THE MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE
WEATHER FOR THE REST OF TODAY AND PRECIP TOMORROW.
TONIGHT...CHANNELED VORTS ON THE CYCLONIC SHEAR SIDE OF THE UPPER
JET WILL BE DIVING SOUTHEAST THIS EVENING ACROSS NORTHERN
WISCONSIN. AMPLE INSTABILITY AROUND 1.5K J/KG COMBINED WITH THIS
FORCING ALOFT SHOULD BE ABLE TO SUSTAIN STORMS INTO EASTERN
WISCONSIN LATER THIS AFTERNOON AND THIS EVENING. AS THE JET STREAK
SHIFTS A LITTLE SOUTH AND THE UPPER LOW MOVES OVER LAKE
SUPERIOR...0-6KM BULK SHEAR VALUES WILL BE DROPPING THIS EVENING.
COMBINED WITH LOSS OF INSTABILITY...SHOULD SEE STORMS DIMINISH IN
INTENSITY BY MID EVENING. STILL SOME SHOWERS COULD POP UP THROUGH
THE NIGHT OVER NORTH-CENTRAL TO NORTH-EAST WISCONSIN AND WILL LEAVE
SMALL POPS IN THE FORECAST FOR THE REST OF THE NIGHT. LOWS IN THE
50S AND 60S.
FRIDAY...THE UPPER LOW OVER LAKE SUPERIOR WILL DROP SOUTHEAST ACROSS
THE CENTRAL GREAT LAKES. AS THIS OCCURS...A DEEP TROUGH WILL DROP
ACROSS THE STATE WHICH SHOULD BRING SHOWERS AND STORMS TO NORTHERN
WISCONSIN DURING THE MORNING. ADDITIONAL STORMS ARE LIKELY IN THE
AFTERNOON WITH HELP FROM DIURNAL INSTABILITY. WITH THE CLOUD COVER
AND COOLER TEMPS...NOT ANTICIPATING ANY SEVERE STORMS AT THIS TIME.
A MOSTLY CLOUDY DAY WITH HIGHS IN THE UPPER 60S TO MID 70S.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 331 PM CDT THU JUN 27 2013
FOR THE EARLY PORTION OR THROUGH
SATURDAY...CONVECTION WILL MAINLY BE ASSOCIATED WITH THE SOUTHWARD
PASSAGE OF THE TROUGH AXIS. PCPN WILL BE ON THE DECREASE FROM
NORTH TO SOUTH ON SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH.
COOLER DRIER AIR WILL FILTER INTO THE STATE ON NORTH WINDS AS A
LARGE HIGH PRESSURE SYSTEM SETTLES INTO THE NORTHERN PLAINS AND
GREAT LAKES REGION. PROBLEM OR CHALLENGE WITH THE LATER PERIODS
CONCERN ORIENTATION OF THE RETROGRADING DEEP UPPER TROUGH OR UPPER
LOW OVER THE SURFACE HIGH PRESSURE. H5 TEMPS PROGGED TO BE ONLY IN
THE -12 C RANGE ABOVE THE SURFACE HIGH...SO NOT REALLY A COOL AIR
MASS ALOFT TO SUPPORT INSTABILITY AFTERNOON PCPN...SO WILL LEAVE
THE SHOWER MENTION OUT OF THE LATER PERIODS FOR NOW...BUT CANNOT
RULE OUT VERY ISOLATED SHOWER ACTIVITY.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1234 PM CDT THU JUN 27 2013
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ACROSS MOST OF NORTH-CENTRAL AND NORTHEAST
WISCONSIN. ANY THUNDERSTORMS WILL HAVE POTENTIAL TO CREATE STRONG
GUSTY WINDS AND NEAR SEVERE HAIL. STORMS WILL CONTINUE TO MID TO
LATE EVENING BEFORE DISSIPATING. THEN AN UPPER LEVEL LOW PRESSURE
SYSTEM WILL DROP SOUTH ACROSS THE REGION LATE TONIGHT INTO
SATURDAY. STATISTICAL GUIDANCE AND PROGGED SOUNDINGS SHOW CIGS
FALLING TO MVFR LEVELS TOMORROW MORNING AND FAIRLY WIDESPREAD SHOWER
ACTIVITY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 PM CDT WED JUN 26 2013
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 231 PM CDT WED JUN 26 2013
SURFACE MAP THIS AFTERNOON HAS A COLD FRONT MOVING EAST ACROSS
EASTERN MN/IA. RADAR SHOWING A BROKEN LINE OF THUNDERSTORMS //SOME
FAIRLY INTENSE TO SEVERE AT TIMES// EXTENDING N-S ALONG THIS FRONTAL
BOUNDARY. LITTLE 0-3KM BULK SHEAR NOTED SO MOST OF THESE STORMS ARE
PULSE-TYPE IN NATURE WITH HIGHER-END RAP 0-1KM ML MUCAPE IN THE
3500-4200J/KG RANGE. THIS UNSTABLE AIR IS BEING PRODUCED BY
TEMPERATURES ACROSS THE AREA IN THE 80-85 DEGREE RANGE AND DEW
POINTS IN THE LOWER 70S.
LOOK FOR THIS FRONT TO SLIP EAST INTO CENTRAL WI THIS EVENING...
DRAGGING THE BULK OF THE SHOWERS/THUNDERSTORMS WITH IT. WITH
PRECIPITABLE WATER VALUES STILL SITTING IN THE 1.5-1.8 INCH
RANGE...ANY SHOWER/THUNDERSTORM EARLY THIS EVENING WILL BE CAPABLE
OF TORRENTIAL DOWNPOURS WITH SOME LOCALIZED PONDING OF WATER
POSSIBLE...ESPECIALLY ACROSS AREAS THAT RECEIVED PREVIOUS HEAVY RAIN
AND HAVE ALREADY SATURATED SOILS.
INTRODUCED A SLIGHT CHANCE OF SHOWER/THUNDERSTORMS MAINLY NORTH OF
I-94 LATER OVERNIGHT//AFTER 09Z// AS A MID-LEVEL TROUGH AND LEFT
EXIT REGION OF 75-100KT 300MB JET PUSHES INTO THIS AREA. MOST OF
THIS ACTIVITY LOOKS ELEVATED/ACCAS TYPE IN NATURE. BUFKIT SHOWS
DRYING IN THE LOWER LEVELS...SO NOT CONFIDENT ON HOW MUCH RAINFALL
WILL ACTUALLY REACH THE SURFACE. THEREFORE...WILL KEEP POPS ON THE
LOW SIDE FOR NOW. THIS MID-LEVEL WAVE CONTINUES TO MOVE ACROSS THE
AREA ON THURSDAY FOR A CONTINUED CHANCE OF SHOWERS AND
THUNDERSTORMS...MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER. MAY
HAVE TO WATCH THIS CONVECTION CLOSELY FOR SEVERE WIND/HAIL THREAT
GIVEN STEEPER LAPSE RATES AND 0-6KM BULK SHEAR IN THE 35-45KT RANGE.
THE GFS... WHICH IS THE DRIEST OF THE MODELS AS FAR AS
DEW POINTS...YIELDS 0-1KM MLCAPE IN THE 1000-1500J/KG RANGE. IN
ADDITION...MAY HAVE SOME ADDED LIFT DUE TO THE LEFT EXIT REGION OF
75-100KT 300MB JET. OTHERWISE...LOOKING FOR A HIGH IN THE
LOWER/MIDDLE 80S WITH DEW POINTS IN THE MIDDLE 60S.
LOOK FOR THE MID-LEVEL WAVE TO EXIT EAST OF THE REGION BY LATE
THURSDAY EVENING...END THE THUNDERSTORM THREAT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 231 PM CDT WED JUN 26 2013
ON FRIDAY...MODELS IN GOOD AGREEMENT IN SWINGING A MID-LEVEL TROUGH
SOUTHWESTWARD INTO THE AREA FROM THE GREAT LAKES REGION. STEEPENING
LAPSE RATES WITH ASSOCIATED COLDER CYCLONIC FLOW ALOFT EXPECTED TO
PRODUCE SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS
MAINLY EAST OF THE MISSISSIPPI RIVER. OTHERWISE...PLAN ON HIGHS
COOLING SOMEWHAT INTO THE MID 70S TO AROUND 80 WITH FAIRLY BREEZY
NORTHWEST WINDS IN THE 10-20 MPH RANGE.
LOOK FOR COOLER CONDITIONS WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORM ACTIVITY TO CONTINUE FRIDAY NIGHT THROUGH SATURDAY AS
THE MID-LEVEL TROUGH SWINGS SOUTH THROUGH THE AREA. HIGHS ON
SATURDAY WILL ACTUALLY SLIP SLIGHTLY BELOW NORMAL LEVELS IN THE
LOW-MID 70S. APPEARS SHOWERS WILL BE EXITING THE AREA COMPLETELY BY
SATURDAY EVENING AS THE TROUGH SHIFTS SOUTHEAST TOWARD THE OHIO
RIVER VALLEY AND RIDGING BUILDS IN FROM THE NORTHWEST.
FOR SUNDAY THROUGH WEDNESDAY...PLAN ON COOLER/OVERALL DRIER
CONDITIONS AS A MAJOR MID-LEVEL TROUGH ESTABLISHES ITSELF OVER THE
CENTRAL CONUS WITH A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN
CONUS. EC REMAINS DRY DESPITE COOLER CYCLONIC FLOW AND THE GFS IS
LIGHT AND SPOTTY WITH ITS QPF. LOOKS LIKE MAINLY SOME DAYTIME
CUMULUS BUT REMAINING DRY. OTHERWISE...HIGHS ARE EXPECTED TO BE IN
THE 75-80 DEGREE RANGE WITH OVERNIGHT LOWS MAINLY IN THE 50S...VERY
PLEASANT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1150 PM CDT WED JUN 26 2013
THE MAIN FOCUS AT THE TAF SITES IS WITH THE POTENTIAL FOR VALLEY
FOG AT LSE ALONG WITH WHETHER ANY PRECIPITATION WILL OCCUR. A COLD
FRONT IS SLOWLY MOVING THROUGH THE REGION WITH DRIER AIR MOVING IN
WITH IT. HOW FAST THIS DRIER AIR MOVES INTO LSE IS THE BIG
QUESTION AS DEW POINT DEPRESSIONS REMAIN LOW AS OF MIDNIGHT. IF
WINDS REMAIN LIGHT...EXPECT THAT SOME VALLEY FOG WILL BE POSSIBLE
BY DAY BREAK. AS FAR AS THUNDERSTORMS GO...LSE WILL HAVE THE BEST
CHANCES ON THURSDAY AFTERNOON BUT EXPECT THAT MUCH OF THE
PRECIPITATION WILL END UP TO THE EAST OF IT. OVERALL...MAINLY
EXPECT THAT CONDITIONS WILL BE VFR WITH WINDS SHIFTING TO THE
NORTHWEST AND BECOMING GUSTY AT TIMES THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1101 PM MDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 951 PM MDT FRI JUN 28 2013
UPDATED GRIDS...MAINLY POPS...TO ACCOUNT FOR TRAINING
THUNDERSTORMS MOVING SOUTH ALONG THE I-25 CORRIDOR. -PJC
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 256 PM MDT FRI JUN 28 2013
...MORE STORMS FOR THE PLAINS LATER TODAY...
THE TWO MAIN CONCERNS THIS AFTERNOON/TONIGHT AND TOMORROW ARE THE
CHANCES OF SEVERE THUNDERSTORMS ACROSS THE I-25 CORRIDOR AND EASTERN
PLAINS...AND HEAVY PRECIPITATION IN AND AROUND BURN AREAS.
CURRENTLY...A SMALL CIRCULATION 20 TO 30 MILES NNW OF COS...WITH ASSOCIATED
QUASISTATIONARY BOUNDARY...IS HELPING TO ENHANCE THUNDERSTORM
DEVELOPMENT ALONG THE HIGHER TERRAIN. ESPECIALLY IN TELLER COUNTY
WHERE NUMEROUS CG STRIKES HAVE BEEN DETECTED WITH A STRONG CELL
CURRENTLY MOVING SOUTHWARD TOWARDS CANON CITY. THE 12Z GFS40 PV15
ALSO SHOWS A WEAK MIDLEVEL DISTURBANCE COMING THROUGH THE
NORTHWEST FLOW AROUND 00Z TONIGHT. THESE INGREDIENTS...ALONG WITH
DEWPOINTS IN THE 30`S AND 40`S ALONG THE I-25 CORRIDOR...WILL AID
IN KEEPING THUNDERSTORMS GOING AFTER SUNSET. SOME OF THESE STORMS
COULD BRIEFLY BECOME SEVERE...MINALY DUE TO GUSTY OUTFLOW WINDS.
LATER TONIGHT...THE HRRR/RAP/NAM12 CONTINUE TO INDICATE
THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS THE PLAINS THROUGH 06Z. THE
MODELS...ESPECIALLY THE HRRR AND RAP...SEEM A BIT OVERDONE ON THE
MOISTURE (CURRENT TD IN LHX IS 26)...BUT STILL FEEL ISOLATED
THUNDERSTORMS WILL BE POSSIBLE ACROSS THE PLAINS TONIGHT.
THE PRIMARY THREAT FROM THESE STORMS WILL LIKELY BE WIND...BUT IF
MOISTURE DOES RETURN VIA A NORTHEASTERLY SURGE AS THE RAP AND HRRR
FORECAST...SOME SMALL HAIL IS POSSIBLE AS 0-6KM BULK SHEAR IS
30-40KTS ACROSS THE PLAINS.
THE NAM12/GFS/EC ALL SHOW ANOTHER...MORE SIGNIFICANT...DISTURBANCE
IN THE NORTHWEST FLOW PUSHING THROUGH THE AREA SATURDAY MORNING.
THIS DISTURBANCE WILL DROP A COLD FRONT THROUGH THE AREA AROUND 12Z
SATURDAY. THIS WILL CREATE GUSTY NORTHEASTERLY WINDS AND HELP DROP
700MB TEMPERATURES TO AROUND 11C...LEADING TO COOLER MAX
TEMPERATURES AND INCREASED MOSITURE ACROSS THE FORECAST AREA.
THUNDERSTORMS ARE LIKELY ONCE AGAIN ACROSS THE MOUNTAINS DURING
THE LATE MORNING AND AFTERNOON. CURRENT ACTIVE BURN AREAS SUCH AS
THE WEST FORK COMPLEX AND EAST PEAK FIRES...ALONG WITH THE WALDO
CANYON SCAR...WILL NEED TO MONITORED FOR FLOODING POTENTIAL
TOMORROW AFTERNOON. THE POTENTIAL WILL EXIST ONCE AGAIN FOR
ISOLATED SEVERE STORMS ACROSS THE EASTERN PLAINS DUE TO THE
INCREASE IS MOISTURE. -PJC
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 256 PM MDT FRI JUN 28 2013
...COOLER TEMPERATURES WITH CONTINUED CHANCES OF RAIN...AND FLASH
FLOODING CONCERNS FOR THE BURN SCARS...
AN ACTIVE PERIOD IS EXPECTED AS THE UPPER LEVEL RIDGE AXIS SHIFTS
WEST AND REMAINS CENTERED THROUGH THE GREAT BASIN. NORTHERLY FLOW
ALOFT IS EXPECTED ACROSS COLORADO THROUGH AT LEAST TUESDAY. AT THE
SURFACE...EXPECT EAST TO SOUTHEAST UPSLOPE SURFACE FLOW TO
CONTINUE WITH DEWPOINTS IN THE 50S ACROSS THE PLAINS SUNDAY.
MODELS SHOW A WEAK DISTURBANCE MOVING THROUGH THE FLOW ALOFT
SUNDAY AND CURRENT MODEL TIMING SHOWS IT MOVING THROUGH SOUTHEAST
COLORADO DURING PEAK HEATING. WITH COOLER AIRMASS IN PLACE...CAPES
IN THE 1000-1500J/KG RANGE ALONG THE SOUTHEAST COLORADO MOUNTAINS...
EXPECT TO HAVE ANOTHER DAY OF CONVECTION FIRING BY EARLY AFTERNOON
OVER THE HIGHER ELEVATIONS. PRIMARY CONCERN WOULD BE FOR LOCALLY
HEAVY RAINFALL TO IMPACT ONE OF THE BURN SCARS
SUNDAY...HOWEVER...WITH ENOUGH SURFACE HEATING...
INSTABILITY...AND FAVORABLE WIND SHEAR PROFILES...A FEW OF THE
STORMS COULD BECOME STRONG TO SEVERE. THIS GENERAL PATTERN
CONTINUES THROUGH TUESDAY ALTHOUGH CAPES AND DEWPOINTS DECREASE
MONDAY AND TUESDAY WHICH WILL LIMIT THE COVERAGE...INTENSITY...AND
RAINFALL POTENTIAL OF THUNDERSTORMS.
ON WEDNESDAY...A STRONG UPPER LEVEL DISTURBANCE MOVES SOUTH
THROUGH THE BACKSIDE OF THE TROF AXIS AND CLOSES OFF OVER THE HIGH
PLAINS THURSDAY. GFS FORECASTS THE CLOSED LOW TO RETROGRADE FRIDAY
TO SOUTHWESTERN SOUTH DAKOTA. THE ECMWF KEEPS THE CLOSED LOW
FARTHER SOUTH...OVER WESTERN KS AND THE OK/TX PANHANDLES. THE GFS
SCENARIO...WHICH HAS BEEN CONSISTENT FOR A FEW RUNS NOW...KEEPS
SOUTHEAST COLORADO IN A COOL AND ACTIVE PATTERN WITH THUNDERSTORM
CHANCES EACH DAY FROM WEDNESDAY THRU FRIDAY. THE ECMWF SCENARIO
KEEPS BEST PRECIPITATION CHANCES TO THE SOUTH AND EAST OF THE CWA.
STILL EXPECT THE COOLER TEMPERATURES AND INCREASED RELATIVE
HUMDITIES TO BRING SOME RELIEF TO WILDFIRE THREAT. STARK
&&
.AVIATION...
ISSUED AT 1057 PM MDT FRI JUN 28 2013
AFTER SOME GUSTY THUNDERSTORM OUTFLOW WINDS TONIGHT...ESPECIALLY
AT KPUB...THUNDERSTORMS AND ASSOCIATED OUTFLOW WINDS WILL ONCE
AGAIN BE THE PRIMARY METEOROLOGICAL CONCERN AT KALS...KCOS...AND
KPUB ONCE AGAIN SATURDAY. THE BEST CHANCE FOR THUNDERSTORMS WILL BE AT
KCOS AND THE SURROUNDING MOUNTAINS. OUTSIDE OF THE THUNDERSTORM
ACTIVITY...GENERALLY VFR CONDITIONS SHOULD BE NOTED AT KALS...KCOS
AND KPUB INTO SATURDAY.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
426 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE AREA REMAINS POSITIONED BETWEEN A BROAD UPPER TROUGH AND A
BERMUDA HIGH INTO THE BEGINNING OF THE COMING WEEK. THE HIGH
BEGINS TO BUILD TO THE WEST FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SIMILAR STORY ONCE AGAIN TODAY WITH THE REGION REMAINING SITUATED
BETWEEN A BROAD UPPER TROUGH OVER THE GREAT LAKES AND A STRONG
BERMUDA HIGH WELL EAST OVER THE ATLANTIC. THE ASSOCIATED COLD
FRONT WITH THE LATEST SURFACE LOW HAS STALLED OVER THE
NORTHEAST...WITH THE EXPECTATION THIS FRONT THEN REMAINS
STATIONARY OVER THE REGION NOW THROUGH THE WEEKEND. THIS
FRONT...COMBINED WITH MULTIPLE SHORTWAVES ROUNDING THE TROUGH WILL
BRING THE CHC FOR SHOWERS AND THUNDERSTORMS TODAY.
MAIN QUESTION OF THE DAY IS THE TIMING AND COVERAGE OF ANY PCPN.
LATEST HRRR AND 00Z SPC WRF STILL HINT AT SOME ISO-SCT COVERAGE
GENERALLY OVER THE EASTERN AREAS OF LONG ISLAND AND CT AROUND 12Z
THIS MORNING SO CONTINUED THE MENTION OF SHOWERS WITH ISO TSTM.
THE MODELS THEN HINT AT DRYING FOR THE REST OF THE MORNING INTO
THE AFTN...WITH THE NEXT CHC FOR ANY SHOWERS AND TSTMS BEING LATE
AFTN INTO THE EVENING AS A SHORTWAVE AND ASSOCIATED VORT MAX MOVE
THROUGH THE AREA. THE FRONT POSITIONS ITSELF JUST WEST...AND
POSSIBLE CONVERGENCE ALONG THIS BOUNDARY COULD ALSO ASSIST IN
PRODUCING SCT SHOWERS AND TSTMS. INSTABILITY VALUES REMAIN AROUND
1000 J/KG...AND WITH BULK SHEAR VALUES BETWEEN 15 AND 25 KTS...NOT
EXPECTING MUCH IN THE FORM OF ANY STRONG TO SEVERE TSTMS TODAY.
TEMPS EXPECTED TO BE A FEW DEGREES ABOVE NORMAL TODAY...GENERALLY
IN THE 80S ACROSS THE REGION.
THERE IS A HIGH RISK FOR RIP CURRENTS TODAY THROUGH THIS EVENING
AT THE ATLANTIC BEACHES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SCT SHOWERS AND THUNDERSTORMS POSSIBLE INITIALLY THIS EVENING WITH
THE LAST BIT OF DAYTIME HEATING PRODUCING JUST ENOUGH INSTABILITY
INLAND...ALONG WITH THE PASSING OF THE SHORTWAVE THAT COULD
TRIGGER A FEW MORE SHOWERS AND TSTMS. HOWEVER...WITH THE LOSS OF
THE HEATING...AND WITH SUBSIDENCE BRIEFLY BUILDING IN
OVERNIGHT...THINKING ANY PCPN SHOULD END BY 06Z...AND WE COULD
ACTUALLY SEE A DRY PERIOD UNTIL AT LEAST MID SUNDAY MORNING. HAVE
CONTINUED THE MENTION OF ISO SHOWERS DURING THIS TIME TO ACCOUNT
FOR A RANDOM SHOWER.
THE CHANCE FOR PCPN INCREASES DURING THE DAY SUNDAY WITH A SURFACE
LOW PRESSURE SYSTEM FOLLOWING THE STATIONARY FRONT...AND NEARING
THE NORTHEAST BY SUNDAY NIGHT. WITH THE PERSISTENT SOUTHERLY
FLOW...PW VALUES SHOOT UP...REACHING AROUND 2 INCHES FOR THE DAY
SUNDAY. THIS COULD LEAD TO HEAVIER RAINS WITH ANY STORMS THAT DO
DEVELOP LATE SUN AFTN. THE PASSING OF A SHORTWAVE LATER IN THE DAY
COULD GENERATE JUST ENOUGH FORCING TO PRODUCE SCT
TSTMS...ESPECIALLY OVER THE INLAND AREA WHERE INSTABILITY VALUES
ARE HIGHER BETWEEN 1000-1500 J/KG. ONCE AGAIN THOUGH...INSTABILITY
AND SHEAR REMAIN LOW ENOUGH TO DIMINISH THE THREAT OF ANY SEVERE
WEATHER.
TEMPS HOVER NEAR TO JUST ABOVE NORMAL FOR THE PERIOD. TEMPS MAY
DIFFER BY A FEW DEGREES DEPENDING ON THE EXTENT OF ANY PCPN THAT
FORMS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A BROAD UPPER TROUGH WILL REMAIN ACROSS THE EASTERN UNITED STATES
SUNDAY NIGHT INTO THE BEGINNING OF THE COMING WEEK. 00Z MODEL
GUIDANCE NOW HINTING AT THE TROUGH WEAKENING SOONER AS THE UPPER
LEVEL RIDGE OVER THE ATLANTIC PUSHES WEST TUES INTO WED. WITH
THIS BEING THE FIRST RUN WITH SUCH A SOLUTION...WILL CONTINUE TO
FOLLOW PREVIOUS FORECAST ON TIMING. HOWEVER...IF THE TROUGH DOES
WEAKEN SOONER...THIS COULD RESULT IN A LESS CHC FOR PCPN TUES-
THURS.
SHORTWAVES WILL ROTATE THROUGH THE UPPER TROUGH FROM TIME TO TIME
DURING THE FIRST PART OF THE WEEK. MEANWHILE SURFACE BERMUDA HIGH
REMAINS ANCHORED OFF THE COAST WITH A SURFACE TROUGH AND WEAK
FRONTAL BOUNDARY REMAINING IN THE VICINITY. THE SHORTWAVES WILL
HELP TRIGGER THE SHOWERS AND THUNDERSTORMS ALONG WITH THE SURFACE
TROUGH. DIURNAL INSTABILITY WILL AID THE DEVELOPMENT OF CONVECTION
EACH AFTERNOON AND EVENING. TIMING OF THE SHORT WAVES TOUGH BUT
WILL BE UNSETTLED THROUGH THE PERIOD...SO WILL CARRY CHANCE POPS
WITH THE HIGHEST IN THE AFTERNOON AND EVENING. WITH A TROPICAL
MOISTURE FEED INTO THE REGION HEAVY RAINFALL WILL BE POSSIBLE WITH
ANY OF THE SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER VALUES
REMAIN AROUND 2 INCHES THROUGH SUNDAY INTO WEDNESDAY.
BY THE END OF THE WEEK...UPPER LEVEL TROUGH WEAKENS...WITH THE
RIDGE AND BERMUDA HIGH THEN PUSHING MORE INTO THE NORTHEAST. THIS
WOULD LEAD TO DRIER WEATHER...WITH STILL A SLIGHT CHC OF
AFTN/EVENING TSTMS. TEMPS FAIRLY CONSISTENT DURING THE COMING
WEEK...REMAINING NEAR NORMAL.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
PERSISTENCE TYPE OF FORECAST WITH A TROUGH SITUATED OVER THE LOWER
HUDSON VALLEY AND AN ONSHORE S/SW FLOW. AIRMASS HAS DRIED SOME
AND WITH NO SIGNIFICANT FORCING MECHANISM...CONVECTION SHOULD BE
ISOLATED AT BEST ACROSS THE TERMINALS TODAY.
WITH THE EXCEPTION OF KGON...THERE MAY BE SOME PATCHY MVFR FOG UP
TO 12Z...OR EVEN A BRIEF PERIOD IFR/MVFR CIGS WITH THE ONSET OF
DAYTIME HEATING AS THE AIRMASS BEGINS TO MIX. KGON WITH THE
TRAJECTORY OF HIGH DEW POINT AIR ACROSS SOME SLIGHTLY COOLER
WATER...LIKELY TO STAY LIFR THROUGH MUCH OF THE MORNING. THERE IS
SOME UNCERTAINTY AS TO WHETHER OR NOT VFR CONDITIONS DEVELOP.
THERE WAS A 3 HOUR WINDOW ON FRI WHERE CIGS WENT VFR WITH MVFR
VSBYS. LIKELY TO SEE A REPEAT.
A LIGHT S/SW FLOW EARLY THIS MORNING WILL INCREASE TO AROUND 10
TO 15 KT BY MIDDAY. GUSTS UP TO 20 KT POSSIBLE.
.OUTLOOK FOR 06Z SUN THROUGH WEDNESDAY...
.SUN-WED...SUB VFR POSSIBLE AT TIMES WITH SCT SHOWERS AND TSTMS.
THERE MAY ALSO BE EPISODES OF STRATUS/FOG AT THE COASTAL TERMINALS
PRODUCING IFR OR LOWER CONDITIONS...WITH THE EMPHASIS ON KGON.
&&
.MARINE...
SCA FOR HAZARDOUS SEAS REMAINS UP ON THE OCEAN WATERS THROUGH
SUN...LIKELY TO TO BE EXTENDED IN SUBSEQUENT FORECAST CYCLES.
A LONG FETCH SOUTHERLY FLOW WILL CONTINUE WELL INTO THE UPCOMING
WEEK WITH SEAS ON THE OCEAN WATERS REMAINING AT OR ABOVE 5 FT.
WAVEWATCH GUIDANCE MAY BE OVERDONE BY ABOUT A FOOT OR TWO...
ESPECIALLY SUN AND MON. WINDS ARE EXPECTED TO STAY BELOW SCA
CRITERIA...GENERALLY 10 TO 20 KT...WITH THE UPPER END OF THE RANGE
ACROSS THE OCEAN WATERS.
THERE WILL BE A CHANCE FOR ISOLATED TO SCT CONVECTION ACROSS THE
WATERS THROUGHOUT THE PERIOD.
&&
.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TODAY THROUGH THE
UPCOMING WEEK. LOCALIZED HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY LATE SUNDAY INTO TUESDAY...WITH LOCALIZED
FLOODING MAINLY OVER URBAN AND POOR DRAINAGE AREAS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING
OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT SUNDAY
FOR ANZ350-353-355.
&&
$$
SYNOPSIS...SEARS
NEAR TERM...SEARS
SHORT TERM...SEARS
LONG TERM...SEARS/MET
AVIATION...DW
MARINE...DW
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
407 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE AREA REMAINS POSITIONED BETWEEN A BROAD UPPER TROUGH AND A
BERMUDA HIGH INTO THE BEGINNING OF THE COMING WEEK. THE HIGH
BEGINS TO BUILD TO THE WEST FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SIMILAR STORY ONCE AGAIN TODAY WITH THE REGION REMAINING SITUATED
BETWEEN A BROAD UPPER TROUGH OVER THE GREAT LAKES AND A STRONG
BERMUDA HIGH WELL EAST OVER THE ATLANTIC. THE ASSOCIATED COLD
FRONT WITH THE LATEST SURFACE LOW HAS STALLED OVER THE
NORTHEAST...WITH THE EXPECTATION THIS FRONT THEN REMAINS
STATIONARY OVER THE REGION NOW THROUGH THE WEEKEND. THIS
FRONT...COMBINED WITH MULTIPLE SHORTWAVES ROUNDING THE TROUGH WILL
BRING THE CHC FOR SHOWERS AND THUNDERSTORMS TODAY.
MAIN QUESTION OF THE DAY IS THE TIMING AND COVERAGE OF ANY PCPN.
LATEST HRRR AND 00Z SPC WRF STILL HINT AT SOME ISO-SCT COVERAGE
GENERALLY OVER THE EASTERN AREAS OF LONG ISLAND AND CT AROUND 12Z
THIS MORNING SO CONTINUED THE MENTION OF SHOWERS WITH ISO TSTM.
THE MODELS THEN HINT AT DRYING FOR THE REST OF THE MORNING INTO
THE AFTN...WITH THE NEXT CHC FOR ANY SHOWERS AND TSTMS BEING LATE
AFTN INTO THE EVENING AS A SHORTWAVE AND ASSOCIATED VORT MAX MOVE
THROUGH THE AREA. THE FRONT POSITIONS ITSELF JUST WEST...AND
POSSIBLE CONVERGENCE ALONG THIS BOUNDARY COULD ALSO ASSIST IN
PRODUCING SCT SHOWERS AND TSTMS. INSTABILITY VALUES REMAIN AROUND
1000 J/KG...AND WITH BULK SHEAR VALUES BETWEEN 15 AND 25 KTS...NOT
EXPECTING MUCH IN THE FORM OF ANY STRONG TO SEVERE TSTMS TODAY.
TEMPS EXPECTED TO BE A FEW DEGREES ABOVE NORMAL TODAY...GENERALLY
IN THE 80S ACROSS THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SCT SHOWERS AND THUNDERSTORMS POSSIBLE INITIALLY THIS EVENING WITH
THE LAST BIT OF DAYTIME HEATING PRODUCING JUST ENOUGH INSTABILITY
INLAND...ALONG WITH THE PASSING OF THE SHORTWAVE THAT COULD
TRIGGER A FEW MORE SHOWERS AND TSTMS. HOWEVER...WITH THE LOSS OF
THE HEATING...AND WITH SUBSIDENCE BRIEFLY BUILDING IN
OVERNIGHT...THINKING ANY PCPN SHOULD END BY 06Z...AND WE COULD
ACTUALLY SEE A DRY PERIOD UNTIL AT LEAST MID SUNDAY MORNING. HAVE
CONTINUED THE MENTION OF ISO SHOWERS DURING THIS TIME TO ACCOUNT
FOR A RANDOM SHOWER.
THE CHANCE FOR PCPN INCREASES DURING THE DAY SUNDAY WITH A SURFACE
LOW PRESSURE SYSTEM FOLLOWING THE STATIONARY FRONT...AND NEARING
THE NORTHEAST BY SUNDAY NIGHT. WITH THE PERSISTENT SOUTHERLY
FLOW...PW VALUES SHOOT UP...REACHING AROUND 2 INCHES FOR THE DAY
SUNDAY. THIS COULD LEAD TO HEAVIER RAINS WITH ANY STORMS THAT DO
DEVELOP LATE SUN AFTN. THE PASSING OF A SHORTWAVE LATER IN THE DAY
COULD GENERATE JUST ENOUGH FORCING TO PRODUCE SCT
TSTMS...ESPECIALLY OVER THE INLAND AREA WHERE INSTABILITY VALUES
ARE HIGHER BETWEEN 1000-1500 J/KG. ONCE AGAIN THOUGH...INSTABILITY
AND SHEAR REMAIN LOW ENOUGH TO DIMINISH THE THREAT OF ANY SEVERE
WEATHER.
TEMPS HOVER NEAR TO JUST ABOVE NORMAL FOR THE PERIOD. TEMPS MAY
DIFFER BY A FEW DEGREES DEPENDING ON THE EXTENT OF ANY PCPN THAT
FORMS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A BROAD UPPER TROUGH WILL REMAIN ACROSS THE EASTERN UNITED STATES
SUNDAY NIGHT INTO THE BEGINNING OF THE COMING WEEK. 00Z MODEL
GUIDANCE NOW HINTING AT THE TROUGH WEAKENING SOONER AS THE UPPER
LEVEL RIDGE OVER THE ATLANTIC PUSHES WEST TUES INTO WED. WITH
THIS BEING THE FIRST RUN WITH SUCH A SOLUTION...WILL CONTINUE TO
FOLLOW PREVIOUS FORECAST ON TIMING. HOWEVER...IF THE TROUGH DOES
WEAKEN SOONER...THIS COULD RESULT IN A LESS CHC FOR PCPN TUES-
THURS.
SHORTWAVES WILL ROTATE THROUGH THE UPPER TROUGH FROM TIME TO TIME
DURING THE FIRST PART OF THE WEEK. MEANWHILE SURFACE BERMUDA HIGH
REMAINS ANCHORED OFF THE COAST WITH A SURFACE TROUGH AND WEAK
FRONTAL BOUNDARY REMAINING IN THE VICINITY. THE SHORTWAVES WILL
HELP TRIGGER THE SHOWERS AND THUNDERSTORMS ALONG WITH THE SURFACE
TROUGH. DIURNAL INSTABILITY WILL AID THE DEVELOPMENT OF CONVECTION
EACH AFTERNOON AND EVENING. TIMING OF THE SHORT WAVES TOUGH BUT
WILL BE UNSETTLED THROUGH THE PERIOD...SO WILL CARRY CHANCE POPS
WITH THE HIGHEST IN THE AFTERNOON AND EVENING. WITH A TROPICAL
MOISTURE FEED INTO THE REGION HEAVY RAINFALL WILL BE POSSIBLE WITH
ANY OF THE SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER VALUES
REMAIN AROUND 2 INCHES THROUGH SUNDAY INTO WEDNESDAY.
BY THE END OF THE WEEK...UPPER LEVEL TROUGH WEAKENS...WITH THE
RIDGE AND BERMUDA HIGH THEN PUSHING MORE INTO THE NORTHEAST. THIS
WOULD LEAD TO DRIER WEATHER...WITH STILL A SLIGHT CHC OF
AFTN/EVENING TSTMS. TEMPS FAIRLY CONSISTENT DURING THE COMING
WEEK...REMAINING NEAR NORMAL.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
PERSISTENCE TYPE OF FORECAST WITH A TROUGH SITUATED OVER THE LOWER
HUDSON VALLEY AND AN ONSHORE S/SW FLOW. AIRMASS HAS DRIED SOME
AND WITH NO SIGNIFICANT FORCING MECHANISM...CONVECTION SHOULD BE
ISOLATED AT BEST ACROSS THE TERMINALS TODAY.
WITH THE EXCEPTION OF KGON...THERE MAY BE SOME PATCHY MVFR FOG UP
TO 12Z...OR EVEN A BRIEF PERIOD IFR/MVFR CIGS WITH THE ONSET OF
DAYTIME HEATING AS THE AIRMASS BEGINS TO MIX. KGON WITH THE
TRAJECTORY OF HIGH DEW POINT AIR ACROSS SOME SLIGHTLY COOLER
WATER...LIKELY TO STAY LIFR THROUGH MUCH OF THE MORNING. THERE IS
SOME UNCERTAINTY AS TO WHETHER OR NOT VFR CONDITIONS DEVELOP.
THERE WAS A 3 HOUR WINDOW ON FRI WHERE CIGS WENT VFR WITH MVFR
VSBYS. LIKELY TO SEE A REPEAT.
A LIGHT S/SW FLOW EARLY THIS MORNING WILL INCREASE TO AROUND 10
TO 15 KT BY MIDDAY. GUSTS UP TO 20 KT POSSIBLE.
.OUTLOOK FOR 06Z SUN THROUGH WEDNESDAY...
.SUN-WED...SUB VFR POSSIBLE AT TIMES WITH SCT SHOWERS AND TSTMS.
THERE MAY ALSO BE EPISODES OF STRATUS/FOG AT THE COASTAL TERMINALS
PRODUCING IFR OR LOWER CONDITIONS...WITH THE EMPHASIS ON KGON.
&&
.MARINE...
SCA FOR HAZARDOUS SEAS REMAINS UP ON THE OCEAN WATERS THROUGH
SUN...LIKELY TO TO BE EXTENDED IN SUBSEQUENT FORECAST CYCLES.
A LONG FETCH SOUTHERLY FLOW WILL CONTINUE WELL INTO THE UPCOMING
WEEK WITH SEAS ON THE OCEAN WATERS REMAINING AT OR ABOVE 5 FT.
WAVEWATCH GUIDANCE MAY BE OVERDONE BY ABOUT A FOOT OR TWO...
ESPECIALLY SUN AND MON. WINDS ARE EXPECTED TO STAY BELOW SCA
CRITERIA...GENERALLY 10 TO 20 KT...WITH THE UPPER END OF THE RANGE
ACROSS THE OCEAN WATERS.
THERE WILL BE A CHANCE FOR ISOLATED TO SCT CONVECTION ACROSS THE
WATERS THROUGHOUT THE PERIOD.
&&
.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TODAY THROUGH THE
UPCOMING WEEK. LOCALIZED HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY LATE SUNDAY INTO TUESDAY...WITH LOCALIZED
FLOODING MAINLY OVER URBAN AND POOR DRAINAGE AREAS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING
OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT SUNDAY
FOR ANZ350-353-355.
&&
$$
SYNOPSIS...SEARS
NEAR TERM...SEARS
SHORT TERM...SEARS
LONG TERM...SEARS/MET
AVIATION...DW
MARINE...DW
HYDROLOGY...SEARS
AREA FORECAST DISCUSSION
NWS MIAMI FL
210 AM EDT SAT JUN 29 2013
.AVIATION...
PRECIPITATION HAS GENERALLY ENDED OVERNIGHT...BUT ISOLATED SHOWERS
APPEAR ON TRACK TO APPROACH ATLC COAST AFTER 3Z. CONFIDENT TOO LOW
TO PLACE VCSH IN FORECAST...HOWEVER. VCTS THIS AFTERNOON/EVENING
AS SCATTERED TO NUMEROUS TSTMS ARE EXPECTED...GRADUALLY
DIMINISHING AFTER SUNSET. WINDS WILL BE MORE SOUTHERLY AFTER
DAYBREAK...AT SPEEDS AVERAGING 10 KTS. VFR CONDITIONS WILL PREVAIL
OUTSIDE OF SHOWERS.
&&
.PREV DISCUSSION... /ISSUED 849 PM EDT FRI JUN 28 2013/
UPDATE...
MAIN AREA OF CONVECTION REMAINS THIS EVENING ACROSS COASTAL PALM
BEACH COUNTY WITH ONLY ISOLATED SHOWERS AND THUNDERSTORMS ACROSS
THE REMAINDER OF THE SOUTH FLORIDA AREA. LATEST SHORT TERM
GUIDANCE KEEPS PARTLY TO MOSTLY CLOUDY SKIES ACROSS THE AREA WITH
REMAINING SHOWERS AND STORMS CONFINED ACROSS MAINLY THE REGIONAL
WATERS OVERNIGHT. UPDATED POP AND QPF GRIDS TO ACCOUNT FOR THE
LATEST TRENDS. UPDATE SENT.
PREV DISCUSSION... /ISSUED 222 PM EDT FRI JUN 28 2013/
SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)...
CURRENTLY, SOUTH FLORIDA CONTINUES TO BE MAINLY INFLUENCED BY THE
DEEP LAYER RIDGE WHICH STRETCHES ACROSS THE REGION INTO THE
ATLANTIC. THIS HAS RESULTED IN MAINTAINING A STEERING FLOW THAT IS
NEARLY NONEXISTENT WITH ERRATIC STORM MOTION. HOWEVER, AS THE DAY
PROGRESSES A MID LEVEL TROUGH WILL BE DEEPENING ACROSS THE EASTERN
U.S. WHICH IN TURN WILL SHIFT THE RIDGE BOTH ALOFT AND AT THE
SURFACE INTO THE FLORIDA STRAITS BY TONIGHT. HINTS OF THIS OCCURRING ARE
BECOMING EVIDENT IN THE RADAR AND SATELLITE SIGNATURES WITH A
VERY SLOW DRIFT TO THE NORTHEAST. THE HRRR IS COMING MORE IN LINE
WITH THAT THINKING ALSO. THE ONLY CONCERN IS THAT THE HRRR ALSO IS
SHOWING GOOD DEVELOPMENT BY 18Z WHICH HAS YET TO OCCUR SO TRENDED
LATER WITH THE HIGHER CHANCES OF CONVECTION.
GLOBAL MODELS CONTINUE WITH THE EVOLUTION OF THE TROUGH DEEPENING
IT THROUGH SUNDAY. AS THIS OCCURS, THE STEERING FLOW WILL BECOME
MORE SOUTHWEST ON SATURDAY WITH THE HIGHEST CHANCES FOR RAIN OVER
THE INTERIOR AND MOST OF THE EAST COAST METRO REGION. THE PRIMARY
THREAT WILL BE LOCALLY HEAVY RAINFALL POSSIBLE ALTHOUGH STORM
MOTION WILL PICK UP TO BETWEEN 5 AND 10 KNOTS AND RELATIVELY WEAK
MID LEVEL LAPSE RATES. THE MODELS ARE NOW SHOWING THE TROUGH
DEEPENING EVEN FURTHER ON SUNDAY WITH A BLOCKING PATTERN SETTING
UP ACROSS NORTH AMERICA AS MASSIVE RIDGES WILL BE IN EXISTENCE
OVER THE DESERT SOUTHWEST AND THE WESTERN ATLANTIC. THIS WILL ALSO
DEVELOP AN EVEN STRONGER DEEP SOUTHWEST STEERING FLOW. IN FACT,
FORECAST SOUNDINGS ARE SHOWING AROUND 20 KNOTS OF WIND IN THE LOW
LEVELS FROM ABOUT 2-7K FEET AND THIS ALONG WITH MID LEVEL LAPSE
RATES STILL NOT VERY IMPRESSIVE COULD LIMIT THE AMOUNT OF THUNDER.
THE KEY FACTOR WILL BE IF A EAST COAST SEA BREEZE WILL BE ABLE TO
DEVELOP WITH SUCH STRONG LOW LEVEL SOUTHWEST WINDS. THE PWAT IS
FORECAST TO BE WELL ABOVE TWO INCHES SO CHANCES FOR RAIN WILL
REMAIN HIGH BUT THERE COULD BE ONLY A FEW LIGHTNING STRIKES
ESPECIALLY WITH THE CONVECTION THAT DEVELOPS EARLY IN THE DAY. AT
THE SAME TIME HOWEVER, BOTH THE MAV AND MET GUIDANCE ARE SHOWING
VERY HIGH CHANCES FOR THUNDER. SO FOR THE TIME BEING WILL NOT
CHANGE THE FORECAST FOR SUNDAY AND WILL WAIT FOR FURTHER GUIDANCE
TO MAKE A DECISION ON WHETHER TO LOWER CHANCES FOR LIGHTNING
STRIKES. ALL IN ALL THOUGH, IT IS SHAPING UP TO BE A WET WEEKEND
FOR THE EAST COAST METRO REGION ESPECIALLY ON SUNDAY.
LONG TERM (MONDAY THROUGH FRIDAY)...
THE BLOCKING PATTERN WILL CONTINUE INTO EARLY NEXT WEEK WITH A
VERY SLOW RETROGRESSION TO THE WEST IN THE OVERALL PATTERN BY THE
MIDDLE OF NEXT WEEK. THIS WILL RESULT IN THE DEEP LAYER RIDGE
EVER SO SLOWLY SHIFTING BACK TO THE NORTH. SO FOR TUESDAY,
FORECAST SOUNDINGS ARE INDICATING A STEERING FLOW MORE SOUTHERLY
AND THEN RETURNING TO A SOUTHEAST DIRECTION BY WEDNESDAY OR
THURSDAY. THE PWAT WILL REMAIN AT NEAR TWO INCHES ALL OF NEXT WEEK
SO THE CHANCES FOR RAIN WILL REMAIN HIGH BUT SHIFT BACK TO THE
INTERIOR AND SOUTHWEST COAST BY WEDNESDAY THROUGH FRIDAY.
MARINE... THE WIND WILL BE MAINTAIN A SOUTH TO SOUTHWEST
DIRECTION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE SEAS
WILL BUILD SLIGHTLY BY SUNDAY IN RESPONSE TO A TIGHTENING PRESSURE
GRADIENT AND INCREASE IN SPEED AS A STRONG TROUGH DEEPENS OVER THE
EASTERN STATES. A SCEC STATEMENT MAY BE NEEDED FOR A PORTION OF
THE WATERS AS SPEEDS COULD INCREASE IN THE RANGE OF 15 TO 20
KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 77 89 76 / 50 30 70 50
FORT LAUDERDALE 88 79 89 78 / 50 40 70 50
MIAMI 90 78 90 78 / 40 40 70 50
NAPLES 91 76 91 76 / 40 30 70 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
158 AM EDT SAT JUN 29 2013
.UPDATE...
NEAR TERM.
CONVECTION HAS DECREASED ACROSS NORTH GA BUT STILL GOING IN SRN
COUNTIES. HAVE TWEAKED POPS/WX AGAIN AND YET AGAIN...TRADITIONAL
MOS GUIDANCE FAILING MISERABLY. RECENT HRRR RUNS AND OTHER HIRES
MODELS ONLY GRADUALLY WEAKEN CONVECTION THRU 12Z BEFORE
DISSIPATING ...ONLY TO FIRE IT UP AGAIN OVER SE COUNTIES BY NOON-
1PM. REST OF FCST LOOKS GOOD. GOOD CHC OF FOG/STRATUS NEAR SUNRISE
ESPECIALLY IN AREAS WHERE MORE THAN A QUARTER OF AN INCH OF RAIN
FELL OVERNIGHT. HAVE USED AWIPS MPE TO INCLUDE PATCHY FOG IN FCST
THRU 13Z. REST OF DISCUSSION OUT SOON.
SNELSON
&&
.PREV DISCUSSION... /ISSUED 740 PM EDT FRI JUN 28 2013/
SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
/ISSUED AT 332 PM EDT FRI JUN 28 2013/
FAIRLY STRONG UPPER LOW SPINNING OVER THE GREAT LAKES AND SOUTHEAST
CANADA WILL ROTATE AROUND AND EVENTUALLY BEGIN TO LIFT NORTHEAST
THROUGH THE SHORT TERM AS A REINFORCING SHORTWAVE DIPS TOWARD THE
OHIO VALLEY LATE IN THE SHORT TERM...DEEPENING THE TROUGH THAT IS IN
PLACE OVER THE EASTERN THIRD OF THE COUNTRY. MULTIPLE SHORTWAVES
EMBEDDED IN THE FLOW COMBINED WITH A SERIES OF COMPLICATED SURFACE
BOUNDARY INTERACTIONS AS WELL AS GENERAL SURFACE WEAKNESSES IN PLACE
IN THE FORM OF A WEAK NEARLY-STALLED FRONT WILL KEEP CONVECTION IN
THE SHORT TERM FORECAST. AS THE FRONT IS PUSHED EAST OVERNIGHT
TONIGHT AND TOMORROW...BEST CONVECTION CHANCES WILL SHIFT TO THE
SOUTH THROUGH THE SHORT TERM.
FOR TONIGHT...WEAK FRONT REMAINS JUST TO THE NORTH OF THE AREA...
HOWEVER LINE OF CONVECTION STRETCHING FROM ATLANTA METRO TOWARD
MONTGOMERY ALABAMA /DEVELOPING ALONG OUTFLOW FROM OVERNIGHT
CONVECTION IN ALABAMA/ HAS LEFT QUITE A BIT OF CONVECTIVE INHIBITION
ACROSS NORTH ALABAMA AND EVEN PORTIONS OF NORTH GEORGIA. AHEAD OF
THE LINE ESPECIALLY IN CENTRAL GEORGIA CAPES HAVE INCREASED TO OVER
5000 J/KG...QUITE A BIT HIGHER THAN WHAT GUIDANCE HAD BEEN PROGGING.
FOR THE MOST PART BEST CONVECTION WILL BE WITH THE CURRENT LINE
ASSOCIATED WITH THE OUTFLOW BOUNDARY...BUT STARTING TO SEE
ADDITIONAL CONVECTION DEVELOP IN TENNESSEE AHEAD OF THE FRONT SO
CANNOT RULE OUT ADDITIONAL DEVELOPMENT UP NORTH. SLIGHT RISK IS IN
PLACE ACROSS MOST OF THE AREA AND SVR WATCH ALREADY OUT FOR WEST
CENTRAL AND SOUTHWEST ZONES. ENOUGH DRY AIR ALOFT ON THE 12Z KFFC
SOUNDING FOR PRECIPITATION LOADING TO KEEP DAMAGING WINDS AND HAIL
REMAIN THE BIGGEST THREATS.
AS THE FRONT SAGS SOUTHEAST OVERNIGHT AND SATURDAY...SO WILL THE
BEST THUNDERSTORM CHANCES AS MUCH DRIER AIR PUSHES IN ALOFT. EXPECT
CONVECTION TO DISSIPATE OVERNIGHT BUT DID KEEP LOW CHANCES GOING IN
SOUTHERN ZONES. ONLY SLIGHT CHANCE POPS UP NORTH BUT LIKELIES SOUTH
IN THE AFTERNOON. CAPES PROGGED BETWEEN 1000-2000 J/KG SOUTH AT BEST
TOMORROW BUT GIVEN THE UNDER-FORECAST OF CAPE TODAY AM NOT CONFIDENT
THAT CAPES WILL REMAIN THAT LOW. CANNOT RULE OUT ISOLATED STRONG
STORMS IN CENTRAL GEORGIA BUT CHANCES FOR SEVERE LOOK PRETTY
LOW...AND SPC DOES NOT EVEN HAVE NORTHERN ZONES IN THE GENERAL
THUNDER AREA.
BEHIND THE FRONT...EXPECT TEMPS AND DEWPOINTS SEVERAL DEGREES
COOLER...WITH HIGHS NEAR TO JUST SLIGHTLY BELOW NORMAL AND LOWS
TRENDING TO BELOW NORMAL BY SATURDAY NIGHT. NOT BAD FOR THE LAST
WEEKEND IN JUNE.
TDP
LONG TERM /SUNDAY THROUGH FRIDAY/...
/ISSUED AT 332 PM EDT FRI JUN 28 2013/
ONLY MINOR TWEAKS TO THE LONG TERM AND THE PREVIOUS DISCUSSION
FOLLOWS.
11
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
NOT MUCH CHANGE IN THE EXTENDED. LARGE UPPER LEVEL TROUGH BEGINS
DIGGING INTO THE SOUTHEASTERN STATES IN THE SHORT TERM...AND TAKES
A HOLD OF THE REGION IN THE EXTENDED. THIS TROUGH DEEPENS OVER THE
GREAT LAKE STATES AND PUSHES SOUTH THROUGH THE WEEKEND INTO EARLY
NEXT WEEK. THIS TROUGH WILL KEEP NORTH AND CENTRAL GA IN MOIST
SOUTHWESTERLY FLOW THROUGH DAY 7. THIS WILL KEEP DIURNALLY DRIVEN
SHOWERS AND THUNDERSTORMS IN THE FORECAST EVERY DAY. THERE IS ALSO
A WEAK BOUNDARY LAYING ACROSS NORTH GA WHICH WILL ACT AS A CATALYST
FOR SHOWERS AND THUNDERSTORMS. WITH VERY LITTLE UPPER LEVEL
MOVEMENT...THIS BOUNDARY IS EXPECTED TO MOVE SOUTHWARD VERY SLOWLY
OVER THE NEXT FEW DAYS. THE MODELS ARE SHOWING IT CONTINUING TO
AFFECT CONVECTIVE DEVELOPMENT THROUGH DAY 7.
01
&&
.AVIATION...
06Z UPDATE...
PRIMARY CONCERNS ARE CHC FOR SUNRISE STRATUS/FOG AND LIKELIHOOD OF
TSRA THIS AFTERNOON. DUE TO OVERNIGHT RAINFALL AND CLEARING SKIES
ALOFT...HAVE ADDED A BRIEF TEMPO FOR IFR CIGS AND SOME IFR VSBYS
DUE TO RADIATIONAL COOLING AND MOIST SFC LAYER. SHOULD MIX OUT
BY 13-14Z. FORTUNATELY...CHC FOR TSRA SHOULD BE MAINLY OVER AREAS
SOUTH OF EAST OF ATL..BASED ON RECENT MODEL RUNS AND EXPECTED
LOCATION OF SFC FEATURES. HAVE INCLUDED PROB30 TSRA FOR ATL METRO
TAF SITES BUT MAY BE ABLE TO REMOVE THIS LATER THIS MORNING. WEST
SFC WINDS MAY GUST TO 14-18KTS THIS AFTERNOON.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON TSRA LIKELIHOOD.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 68 87 68 / 40 40 30 30
ATLANTA 87 69 84 69 / 40 30 30 30
BLAIRSVILLE 82 62 80 63 / 30 20 40 30
CARTERSVILLE 87 65 85 65 / 30 20 30 30
COLUMBUS 90 71 87 70 / 60 40 30 30
GAINESVILLE 86 67 84 68 / 40 20 30 30
MACON 89 71 88 68 / 60 50 40 30
ROME 88 65 86 65 / 20 20 40 30
PEACHTREE CITY 88 66 84 65 / 50 30 30 30
VIDALIA 88 73 86 72 / 70 60 70 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....01
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS WICHITA KS
321 AM CDT SAT JUN 29 2013
.SYNOPSIS...
ISSUED AT 321 AM CDT SAT JUN 29 2013
THE RIDGE OVER THE WESTERN HALF OF THE CONUS HAS AMPLIFIED AND
EXPECTED TO CONTINUE TO DO SO WHILE A MAIN UPPER TROUGH IS OVER
THE EASTERN HALF OF THE CONUS. THE PLAINS IS UNDER UPPER LEVEL
NORTHWESTERLY FLOW. SCATTERED SHOWERS AND THUNDERSTORMS ARE
PRESENT TONIGHT ACROSS CENTRAL AND SOUTHERN KANSAS. THIS AREA IS
JUST SKIRTING THE WICHITA FORECAST AREA. SOME AREAS OF
BARTON...RENO...KINGMAN AND HARPER COUNTIES COULD SEE SOME BRIEF
THUNDERSTORMS. SKIES ARE CLEAR ACROSS THE EASTERN HALF OF THE
STATE WITH MORNING LOWS IN THE 60S.
BILLINGS
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 321 AM CDT SAT JUN 29 2013
THE MAIN UPPER RIDGE WILL CONTINUE TO AMPLIFY AND RETROGRADE
WESTWARD AS MULTIPLE PIECES OF ENERGY DIVE INTO THE TROUGH OVER
THE EAST. WITH THE RIDGE RETROGRADING...WE WILL BE INFLUENCED BY A
COOLER AIRMASS. TEMPERATURES THROUGH MONDAY WILL BE IN THE 80S
AND ACTUALLY DECREASING AS TIME GOES ON. HIGHS IN THE LOW TO MID
80S ARE ABOUT 10 DEGREES BELOW CLIMATOLOGICAL NORMS FOR THE END OF
JUNE/EARLY JULY.
MUCH LIKE THIS MORNING...SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE ACROSS WESTERN KANSAS TONIGHT. THINK THE PLACEMENT
WILL BE JUST A BIT FURTHER TO THE WEST AND HAVE KEPT THE FORECAST
DRY FOR NOW. NORTHERLY WINDS WILL BECOME EASTERLY AS MONDAY
APPROACHES. AS SOME ENERGY APPROACHES FOR MONDAY...SHOWERS AND
THUNDERSTORMS COULD BE POSSIBLE OVER SOUTHEAST KANSAS.
BILLINGS
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 321 AM CDT SAT JUN 29 2013
THE ENERGY IN THE UPPER TROUGH OVER THE EAST WILL SLOWLY DRIFT
SLIGHTLY WESTWARD IMPACTING THE AREA FOR THE EXTENDED. THIS WILL
KEEP TEMPERATURES COOLER THAN NORMS...IN THE 80S. EVENTUALLY A
STRONGER UPPER WAVE WILL BE ABLE TO BREAK THE RIDGE BY THE END OF
THE WEEK...BUT THE ENERGY OVER OUR AREA IS EXPECTED TO REMAIN THROUGH
THE PERIOD. THE ECMWF AND GFS ARE RELATIVELY SIMILAR DURING THE
EXTENDED WITH THE MAIN WAVE STAYING OVER THE CENTRAL PLAINS. THE
PRESENCE OF THE UPPER ENERGY WILL CAUSE PRECIPITATION CHANCES TO
INCREASE FOR MID TO LATE WEEK. CONFIDENCE IS HIGH FOR BELOW NORMAL
TEMPS.
BILLINGS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1148 PM CDT FRI JUN 28 2013
WILL LIKELY SEE A FEW SHOWERS/THUNDERSTORMS OVERNIGHT THROUGH
EARLY-MID MORNING SATURDAY GENERALLY ALONG/WEST OF A LINE
EXTENDING FROM RUSSELL-HUTCHINSON-WELLINGTON...ALONG ZONE OF
700-600MB CONVERGENCE ZONE. THE LATEST HRRR HAS A GOOD HANDLE ON
THIS. AS SUCH HAVE INSERTED VCSH IN RSL-HUT-ICT TAFS. COULD SEE
BRIEF HEAVY RAIN AND SMALL HAIL WITH THE STRONGEST ACTIVITY.
OTHERWISE...MODEST/GUSTY NORTH TO NORTHWEST WINDS WILL PREVAIL
AREAWIDE SATURDAY...SUBSIDING BY EVENING.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 90 63 82 60 / 10 10 0 0
HUTCHINSON 89 62 82 58 / 10 10 0 0
NEWTON 88 61 81 56 / 10 10 0 0
ELDORADO 87 61 81 55 / 10 10 10 0
WINFIELD-KWLD 90 63 83 58 / 10 10 0 0
RUSSELL 88 60 83 54 / 20 10 0 0
GREAT BEND 90 60 83 55 / 20 10 0 0
SALINA 87 61 82 58 / 10 10 0 0
MCPHERSON 88 61 82 57 / 10 10 0 0
COFFEYVILLE 87 63 81 59 / 0 10 10 10
CHANUTE 85 61 80 59 / 0 10 20 10
IOLA 84 60 79 60 / 0 10 20 10
PARSONS-KPPF 86 62 80 58 / 0 10 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1154 PM CDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 1148 PM CDT FRI JUN 28 2013
UPDATED AVIATION SECTION BELOW FOR THE 06Z TAFS.
ADK
&&
UPDATE ISSUED AT 955 PM CDT FRI JUN 28 2013
INCREASING 700-600MB CONVERGENCE IN RESPONSE TO SUBTLE SHORTWAVE
ENERGY RACING SOUTH ACROSS THE MIDWEST MAY RESULT IN A FEW SHOWERS
AND PERHAPS EVEN A THUNDERSTORM OVER PORTIONS OF CENTRAL AND
SOUTH-CENTRAL KS BETWEEN ABOUT 2-9AM OVERNIGHT-SAT MORNING.
LATEST RUC AND HRRR WOULD SUGGEST THE BEST POTENTIAL GENERALLY
WEST/SOUTHWEST OF A LINE EXTENDING FROM RUSSELL TO HUTCHINSON TO
WELLINGTON. HAVE UPDATED THE FORECAST ACCORDINGLY.
ADK
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 107 PM CDT FRI JUN 28 2013
HIGHS THROUGH THE PERIOD ARE EXPECTED TO REMAIN
5-10 DEGREES BELOW NORMAL WITH VALUES IN THE 80S WHILE BREEZY
NORTHERLY WINDS ARE ANTICIPATED DURING THE AFTERNOON/EARLY EVENING
HOURS. LOW TEMPERATURES MAY BE AROUND 10 DEGREES BELOW NORMAL WITH
LOW-LYING AREAS FALLING INTO THE MID AND UPPER 50S THROUGH THE
PERIOD.
.LONG TERM...(WEDNESDAY THROUGH FRIDAY)
ISSUED AT 107 PM CDT FRI JUN 28 2013
LIGHT EAST TO SOUTHEAST WINDS WILL RETURN TO THE CENTRAL PLAINS TOWARD
THE MIDDLE OF THE WEEK WHILE BOTH THE GFS/ECMWF SUGGEST A WEAK
MID/UPPER TROUGH WILL ROUND THE RIDGE AND RESIDE ACROSS THE
CENTRAL CONUS. THIS WILL LEAD TO INCREASING CHANCES FOR SHOWERS
AND THUNDERSTORMS WHILE TEMPERATURES REMAIN BELOW CLIMATOLOGICAL
NORMALS.
MWM
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1148 PM CDT FRI JUN 28 2013
WILL LIKELY SEE A FEW SHOWERS/THUNDERSTORMS OVERNIGHT THROUGH
EARLY-MID MORNING SATURDAY GENERALLY ALONG/WEST OF A LINE
EXTENDING FROM RUSSELL-HUTCHINSON-WELLINGTON...ALONG ZONE OF
700-600MB CONVERGENCE ZONE. THE LATEST HRRR HAS A GOOD HANDLE ON
THIS. AS SUCH HAVE INSERTED VCSH IN RSL-HUT-ICT TAFS. COULD SEE
BRIEF HEAVY RAIN AND SMALL HAIL WITH THE STRONGEST ACTIVITY.
OTHERWISE...MODEST/GUSTY NORTH TO NORTHWEST WINDS WILL PREVAIL
AREAWIDE SATURDAY...SUBSIDING BY EVENING.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 67 89 63 84 / 0 0 0 10
HUTCHINSON 65 89 61 84 / 10 10 10 10
NEWTON 64 87 60 83 / 0 0 0 10
ELDORADO 65 86 60 82 / 0 0 0 10
WINFIELD-KWLD 65 89 61 84 / 0 0 10 10
RUSSELL 64 89 59 84 / 20 20 10 0
GREAT BEND 64 90 60 84 / 20 20 10 0
SALINA 66 88 61 84 / 0 0 0 10
MCPHERSON 65 89 60 84 / 0 0 10 10
COFFEYVILLE 66 86 62 81 / 0 0 0 10
CHANUTE 64 84 60 81 / 0 0 0 10
IOLA 64 83 60 80 / 0 0 0 10
PARSONS-KPPF 64 85 60 81 / 0 0 0 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
333 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE POTENTIAL FOR HEAVY RAINFALL WILL INCREASE THROUGH THE WEEKEND
AS TROPICAL MOISTURE STREAMS INTO THE CAROLINAS. THE UNSETTLED
WEATHER WILL CONTINUE INTO MID WEEK AS AN UNUSUALLY DEEP
UPPER LEVEL TROUGH SITS WEST OF THE REGION...AND INTERACTS WITH BERMUDA
HIGH PRESSURE OFFSHORE. THE PATTERN WILL FINALLY BREAK COME
THURSDAY AS HIGH PRESSURE SHIFTS WESTWARD WITH MORE LIMITED SHOWER
ACTIVITY EXPECTED THROUGH THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM TUESDAY...EXTENSIVE CLOUD COVER HAS LIMITED SURFACE
HEATING AND ATTENDANT CONVECTION TO A CERTAIN EXTENT THIS
AFTERNOON. HOWEVER...ISOLATED CONVECTION IS BEGINNING TO FIRE OFF
WHILE MOVING QUICKLY FROM SW TO NE. ANALYSIS OF MORNING SOUNDINGS
SHOWED A MARGINALLY UNSTABLE AND VERY MOIST ATMOSPHERE TODAY.
LAPSE RATES WERE NOT THAT IMPRESSIVE...BUT A COUPLE OF MAJOR
TRIGGERS IN THE FORM OF AN UPPER SHORT WAVE FOR LATE THIS
AFTERNOON AND EVENING AND A COLD FRONT OVERNIGHT COULD ACT TO
SPARK STRONG TO SEVERE CONVECTION. SPC HAS AREA IN THE SLIGHT RISK
CATEGORY FOR SEVERE WEATHER WITH THE MAIN THREAT BEING FROM
DAMAGING WINDS. THIS LOOKS REASONABLE CONSIDERING JUICY COLUMN AND
POTENTIAL FOR WET-MICROBURSTS. LOCALIZED FLOODING REMAINS A THREAT
ALSO...ESPECIALLY UNDER TRAINING STORMS.
EXPECT SHOWER AND STORM COVERAGE TO INCREASE INTO THE LIKELY
CATEGORY LATER THIS AFTERNOON AND EVENING AS SHORT WAVE APPROACHES.
A CLUSTER OF STRONG THUNDERSTORMS NOW OVER GEORGIA IS HEADED IN THIS
GENERAL DIRECTION AND COULD BRUSH OUR SOUTHERNMOST COUNTIES IF IT
HOLDS TOGETHER. THIS WILL BE ONE OF OUR PRIMARY AREAS OF CONCERN IN
THE VERY NEAR TERM.
COLD FRONT IS FORECAST TO MOVE ACROSS THE FORECAST AREA OVERNIGHT
AND SHOULD BE JUST OFFSHORE BY DAYBREAK. MODEL CONSENSUS HANGS IT UP
JUST ALONG THE COAST THOUGH...SO DO NOT EXPECT MUCH IN THE WAY OF
DRYING IN THE WAKE OF THIS FRONT.
EXPECT SEASONAL TEMPERATURES OVERNIGHT...WITH MINIMUMS RANGING FROM
THE UPPER 60S WELL INLAND TO THE MID 70S AT THE BEACHES.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...VERY WARM AND HUMID AIR MASS WILL REMAIN
IN PLACE IN SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE TO OUR
EAST. MID TO UPPER TROUGH WILL DIG DOWN FROM THE GREAT LAKES INTO
THE LOWER MISSISSIPPI VALLEY THROUGH EARLY NEXT WEEK. LOCAL AREA
WILL REMAIN IN BETWEEN RIDGE TO THE EAST AND THIS TROUGH TO THE
WEST. THIS WILL PRODUCE A DEEP SOUTHERLY FLOW OF MOIST TROPICAL
AIR. LOW LEVEL FLOW WILL REACH UP TO 30 TO 40 KTS PUMPING THIS
WARM MOIST AIR IN. PCP WATER VALUES WILL BE OVER 2 INCHES THROUGH
MUCH OF THE PERIOD. PLENTY OF SHORTWAVE ENERGY WILL RIDE AROUND
THIS HIGHLY AMPLIFIED TROUGH AND DECENT JET DYNAMICS WILL BE IN
PLACE SUNDAY THROUGH MONDAY. MOISTURE PROFILES AND SOUNDINGS SHOW
VERY DEEP LAYER MOISTURE THROUGH THE COLUMN. OVERALL EXPECT A VERY
WET PERIOD WITH SHOWERS AND THUNDERSTORMS AT ANY TIME. WITH DEEP
MOISTURE AND LIFT EXPECT TORRENTIAL RAIN IN THUNDERSTORMS AND
POSSIBILITY OF WET MICROBURSTS TO CREATE A DAMAGING WIND THREAT.
JUNE MAY FINISH UP WITH RECORD OR NEAR RECORD RAINFALL FOR THE
MONTH.
IN WILMINGTON...10.34 INCHES OF RAIN HAS FALLEN THIS MONTH WHICH
IS 2.53 INCHES UNDER THE JUNE RECORD OF 12.87" (1962).
IN FLORENCE...7.89 INCHES OF RAIN HAS FALLEN THIS MONTH WHICH IS
1.30INCHES UNDER THE RECORD OF 9.29" (1961).
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...DEEP SOUTHERLY FLOW OF WARM AND MOIST
AIR WILL CONTINUE THROUGH TUES INTO WEDNESDAY BUT THE MID TO UPPER
TROUGH WILL LIFT OFF TO THE NORTHEAST AS STRONG RIDGE BUILDS IN
FROM THE EAST. HIGH PRESSURE FROM THE SURFACE UP THROUGH THE MID
TO UPPER LEVELS WILL BUILD WESTWARD PROVIDING INCREASED SUBSIDENCE
AND DRYING THROUGH THE LOW TO MID LEVELS OF THE ATMOSPHERE.
ALTHOUGH THE WARM AND HUMID AIR MASS WILL REMAIN AT THE
SURFACE...THE SUBSIDENCE AND DRYING ALOFT WILL LIMIT THE
CONVECTIVE POTENTIAL. MOISTURE PROFILES SHOW A VERY DRY ATMOSPHERE
FROM ABOUT 4K FT UPWARDS. BASICALLY EXPECT FOG OVERNIGHT INTO
EARLY MORNING HOURS AS DEWPOINT TEMPS CONTINUE UP AROUND 70 AND
BETTER RADIATIONAL COOLING POTENTIAL EXISTS. THEREFORE MAY SEE LOW
CLOUDS IN THE MORNING LIFTING INTO STRATOCU...BUT EXPECT MORE
LIMITED SHWR ACTIVITY THURS INTO NEXT WEEKEND WITH INCREASED
SUBSIDENCE AND DRY AIR ALOFT.
WARM AND HUMID CONDITIONS WILL PERSIST WITH WINDS BACKING AROUND
TO THE SOUTHEAST AND LIGHTENING UP AS GRADIENT WEAKENS AS CENTER
OF HIGH MOVES CLOSER. TEMPS RUNNING RIGHT AROUND NORMAL FOR THIS
TIME OF YEAR WITH HIGHS PUSHING 90 AND LOWS IN THE LOWER 70S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...MCS TO OUR NORTH MAY SPAWN SOME CONVECTION MOVING INTO
LBT AND PERHAPS FLO AN HOUR OR TWO AFTER TAF ISSUANCE. TOWARD
MORNING...DEEP MOISTURE IN PLACE AT ALL TERMINALS...WITH SCATTERED
CONVECTION EXPECTED...WITH ISOLATED THUNDER. CONFIDENCE IS WANING A
BIT HOWEVER AS THE HRRR AND NAM SEEM TO BE BACKING OFF A BIT.
CEILINGS WILL LOWER TO MVFR WITH BRIEF IFR VISIBILITIES IN THE
HEAVIER SHOWERS. SATURDAY...EXPECT INTERMITTENT CONVECTION MOST OF
THE DAY. SOME DRYING ALOFT IS INDICATED AT THE INLAND
TERMINALS...HOWEVER THIS MAY JUST ALLOW MORE HEATING FOR POSSIBLE
AFTERNOON THUNDERSTORMS. AGAIN MVFR CEILINGS ARE EXPECTED THROUGHOUT
MOST OF THE DAY.
EXTENDED OUTLOOK...ISOLATED/SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM TUESDAY...TIGHTENING GRADIENT IN ADVANCE OF A COLD
FRONT WILL PUSH SWLY WINDS INTO THE 15 TO 20 KT RANGE THIS EVENING
AND OVERNIGHT. SEAS WILL BUILD AS A RESULT...WITH 4 TO 6 FT SEAS
OVER OUR NC WATERS AND 3 TO 5 FT DOWN SOUTH. RAISING A SMALL CRAFT
ADVISORY FOR NC WATERS WITH THIS PACKAGE...AND EXERCISE CAUTION
STATEMENTS FOR OUR SC WATERS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...TIGHTENED GRADIENT FLOW WILL PERSIST
BETWEEN DEEP TROUGH REMAINING WEST OF AREA AND HIGH PRESSURE TO
THE EAST. THIS WILL MAINTAIN SOUTHERLY WINDS UP TO 15 TO 20 KTS
THROUGH MUCH OF THE PERIOD WHICH IN TURN WILL KEEP SEAS 4 TO 7 FT
HIGH. EXPECT SMALL CRAFT CONDITIONS TO CONTINUE THROUGH MUCH OF
THE PERIOD WITH WNA SHOWING A SLIGHT DROP IN WINDS AND SEAS SUN
AFTN FOLLOWED BY A SPIKE UP BY MONDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL ALSO BE QUITE WIDESPREAD THROUGH MUCH OF THE
PERIOD CREATING PERIODS OF HEAVY RAIN AND REDUCED VISBYS.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...GRADIENT WILL BEGIN TO RELAX MID TO LATE
WEEK AS HIGH PRESSURE TO THE EAST PUSHES WESTWARD AND LOW PRESSURE
TO THE WEST WEAKENS AND LIFTS NORTH. EXPECT SOUTHERLY WINDS
INITIALLY TO MAINTAIN 15 TO 20 KTS WITH A GRADUAL WEAKENING AND
BACKING OF WINDS TO THE S-SE THROUGH THE PERIOD. WNA SHOWS SEAS
DROPPING BELOW SCA THRESHOLDS TUES MORNING...MAINTAINING 3 TO 5 FT
THROUGH TUES NIGHT AND DROPPING TO 2 TO 4 FT THROUGH WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EDT SUNDAY FOR AMZ250-252-254-
256.
&&
$$
NEAR TERM...REK
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...REK/DL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 AM EDT SAT JUN 29 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL EXTEND ACROSS THE EASTERN U.S. THROUGH
EARLY NEXT WEEK. THIS WEATHER SYSTEM WILL BRING PERIODS OF UNSETTLED
WEATHER TO CENTRAL NC THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 PM FRIDAY...
THE SEVERE THUNDERSTORM WATCH EXPIRED AT 1000 PM. HOWEVER... ANOTHER
MID/UPPER LEVEL DISTURBANCE SET UP NEW CONVECTION ALONG THE OLD W-E
OUTFLOW BOUNDARY FROM NEAR CLT TO SW OF RDU IN THE PAST TWO HOURS. A
FLASH FLOOD THREAT CONTINUES ESPECIALLY IN STANLY COUNTY WHERE THE
FLASH FLOOD GUIDANCE IS LOW... CURRENTLY 2 INCHES IN 2 HOURS. THIS
WILL EASILY BE EXCEEDED WITH THE TRAINING OF SEVERAL LARGE STORMS
OVER THAT REGION BEFORE 1200 AM. RAINFALL RATES ARE NEARLY 2 INCHES
PER HOUR IN THESE STORMS. THIS MAY BECOME A VERY SERIOUS THREAT TO
LIFE AND PROPERTY IF THE CELLS REMAIN AS INTENSE AS THEY ARE
CURRENTLY... WITH SEVERAL MORE TO GO... ONE OVER WESTERN STANLY...
ONE OVER CABARRUS... AND THE LAST IN THE SERIES OVER CHARLOTTE.
EVERYONE IN STANLY COUNTY SHOULD TAKE THIS FLOOD THREAT VERY
SERIOUSLY AND HEAD ALL WARNINGS AND STATEMENTS. REMEMBER FLOODING IS
IMPOSSIBLE TO SEE AT NIGHT. DO NOT DRIVE IN THIS SITUATION.
FLASH FLOODING MAY BECOME AN ISSUE ALONG AND NORTH OF THE
W-E OUTFLOW FROM STANLY EAST THROUGH MONTGOMERY... PORTIONS OF
CHATHAM... LEE... WAKE... AND POSSIBLY DURHAM COUNTIES THROUGH 200
AM... DUE TO THE TRAINING OF STORMS ALONG AND NORTH OF THE OLD
OUTFLOW. THE HRRR SEEMS TO HAVE A FAIR GRIP ON THIS SITUATION...
WITH THE TRAINING OF STORMS POSSIBLE INTO THE FAY AND RDU AREAS...
BUT FOCUSED ON STANLY... MONTGOMERY... NW MOORE THROUGH 1200 AM.
&&
.SHORT TERM /SATURDAY AND SUNDAY NIGHT/...
AS OF 245 PM FRIDAY...
FOR SATURDAY/SATURDAY NIGHT: CONTINUED WARM... DAMP... AND HUMID.
WE`LL REMAIN BENEATH CLIMATOLOGICALLY FAST CYCLONIC MID LEVEL FLOW
HEADING INTO THE WEEKEND. MODELS SHOW THE SURFACE TROUGH SHIFTING TO
THE COASTAL PLAIN SATURDAY MORNING WITH MARKEDLY LOWER SURFACE
THETA-E VALUES PUSHING INTO THE WRN FORECAST AREA. EXPECT TO SEE
SOME LINGERING PATCHY SHOWERS ALONG WITH AREAS OF STRATUS OVER THE
COASTAL PLAIN SATURDAY MORNING... BUT WEAK TO ABSENT DYNAMIC FORCING
FOR ASCENT AND TYPICALLY LOWER INSTABILITY AND LINGERING CINH THAT
TIME OF DAY WILL LIMIT COVERAGE/STRENGTH OF ANY CONVECTION DURING
THE MORNING... AND THE WRN PIEDMONT SHOULD REMAIN DRY THROUGH
MIDDAY. WITH THE INJECTION OF ENERGY DOWN ITS WEST SIDE... THE MID
LEVEL TROUGH IS EXPECTED TO DIG STRONGLY DOWN LAKE MICHIGAN INTO IN
AND THE WRN OH VALLEY THROUGH SATURDAY NIGHT... CAUSING A BACKING OF
MID LEVEL WINDS OVER NC TO A MORE SOUTHERLY DIRECTION AND A GRADUAL
STRENGTHENING AND BUILDING OF THE ATLANTIC ANTICYCLONE WESTWARD
TOWARD COASTAL NC. THIS WILL EFFECTIVELY LEAD TO DISSIPATION OF THE
ERN NC SURFACE TROUGH WHILE THE MORE SUBSTANTIAL FRONTAL ZONE
STRENGTHENS TO OUR WEST AND HIGH PW VALUES REBOUND BACK WESTWARD
THROUGH CENTRAL NC WITH AN ATTENDING RESURGENCE OF HIGHER 850 MB
THETA-E. THE NAM/GFS HANDLE THEIR PRECIP FIELDS DIFFERENTLY WITH THE
NAM HOLDING WIDESPREAD CONVECTION TO OUR EAST AND WEST UNTIL VERY
LATE SATURDAY NIGHT... WHILE THE GFS DEVELOPS CONVECTION WITH
HEATING SATURDAY AFTERNOON ESPECIALLY ALONG THE HIGHWAY 1
CORRIDOR... WHICH THEN PERSISTS THROUGH THE NIGHT AS THE 2+ INCH
PRECIP WATER VALUES SPREAD FROM THE COAST WESTWARD THROUGH ALL OF
CENTRAL NC. THE GFS`S PATTERN LOOKS TO BE A MORE REASONABLE
SCENARIO... WITH MORE SCATTERED DISCRETE CELLS IN THE FAR WRN
PIEDMONT (WHERE SURFACE DEW POINTS AND HENCE INSTABILITY WILL LIKELY
BE A BIT LOWER) TRENDING TO NUMEROUS CLUSTERS OF MULTICELLS ROUGHLY
EAST OF A LINE FROM ROXBORO TO SILER CITY TO WADESBORO (ATTENDING
THE GREATER INSTABILITY AND PW). THE BACKED STEERING FLOW AND
EXPECTED ORIENTATION OF CONVECTIVE BANDS WILL BRING ABOUT A CONCERN
FOR TRAINING ECHOES AND LOCALIZED URBAN AND STREET FLOODING AND
SWOLLEN CREEKS STARTING SATURDAY... ESPECIALLY CONSIDERING THE
IMPROVING UPPER DIVERGENCE OVER CENTRAL/ERN NC IN THE RIGHT ENTRANCE
REGION OF THE SOUTHERLY JET TO OUR NNW. AFTER MUCH COORDINATION AND
DISCUSSION... WILL NOT GO WITH A FLASH FLOOD WATCH AS YET... AS
WIDESPREAD HEAVY RAIN HAS YET TO MATERIALIZE IN THE ERN
PIEDMONT/SANDHILLS/COASTAL PLAIN WHERE THE MORE SANDY SOIL AND
FLATTER TERRAIN RESULTS IN SLOWER RUNOFF... BUT URBAN AREAS WILL
REMAIN VULNERABLE TO SOME FLOODING. WE WILL CONTINUE TO RE-EVALUATE
AND CONSIDER THIS RISK AS WE HEAD THROUGH THE WEEKEND. WILL HAVE A
GOOD CHANCE OF SHOWERS/STORMS WEST SATURDAY AFTERNOON/NIGHT WITH
LIKELY POPS ALONG/EAST OF THE AFOREMENTIONED LINE COVERING THE
CENTRAL/ERN CWA. DEEP LAYER SHEAR IS NOT TREMENDOUS BUT DOES IMPROVE
FURTHER TO 25-35 KTS... ALTHOUGH MODEL MLCAPE VALUES ONLY PEAK AT
800-1500 J/KG SATURDAY AFTERNOON ALONG/EAST OF HIGHWAY 1...
SUGGESTING PERHAPS A MORE MOIST-ADIABATIC PROFILE THAN WE`VE SEEN
LATELY. POTENTIALLY WEAKER UPDRAFTS ESPECIALLY ALOFT COULD LOWER THE
RISK OF SEVERE STORMS... BUT AGAIN THE DEEP WARM LAYER (LCL TO
FREEZING DEPTH NEAR 4 KM) AND PW NEAR 2 INCHES (WHICH IS NEARLY 2
STANDARD DEVIATIONS ABOVE NORMAL) SUPPORT A HEAVY RAIN THREAT WITH
WARM RAIN PROCESSES DOMINATING. HIGHS 87-91. LOWS 68-72. -GIH
THE WELL-ADVERTISED DEVELOPING TROUGH ALOFT WILL HAVE BECOME
STRONGLY AMPLIFIED AND ESTABLISHED OVER THE TN VALLEY THIS
PERIOD...BETWEEN A PAIR OF ANOMALOUSLY STRONG RIDGES OVER WESTERN N.
AMERICA AND THE WESTERN N. ATLANTIC. WHILE LOW LEVEL CONVERGENCE IN
ASSOCIATION WITH A LEE TROUGH/WEAK FRONT WILL HAVE DIMINISHED FROM
PREVIOUS DAYS...THE PATTERN OF PERTURBED SW TO SSW DEEP LAYER FLOW
WILL DRIVE NUMEROUS TO WIDESPREAD SHOWERS/STORMS...AMIDST A DEEP
MOIST AXIS CHARACTERIZED BY PRECIPITABLE WATER VALUES AROUND TWO
INCHES...SUNDAY AND LIKELY THROUGHOUT SUNDAY NIGHT. DEEP LAYER SHEAR
ON THE ORDER OF 25-30 KTS...TO PERHAPS 35 KTS OVER THE NW
PIEDMONT...WILL SUPPORT PRIMARILY MULTI-CELL BANDS CAPABLE OF
PRODUCING WET MICROBURSTS...AND TO A GREATER EXTENT LOCALIZED
FLOODING OWING THE ANOMALOUSLY HIGH PW/S. HIGHS GENERALLY IN THE MID
80S...AND LOWER 70S FOR LOWS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 PM FRIDAY...
CONTINUED...IF NOT INCREASINGLY...WET. THE LARGE SCALE
RIDGE/TROUGH/RIDGE CONFIGURATION ACROSS NOAM WILL GRADUALLY
RETROGRESS...WITH THE TROUGH DRIFTING WESTWARD INTO THE MS
VALLEY...THROUGH MID-LATE WEEK. THE PRESENCE AND PERSISTENCE OF THE
TROUGH WILL KEEP MUCH OF THE EASTERN US...INCLUDING CENTRAL NC...IN
A PATTERN OF PERTURBED AND DEEPLY MOIST SW TO SSW FLOW ALOFT -
FAVORABLE FOR ABOVE AVERAGE PRECIPITATION CHANCES...PARTICULARLY
THROUGH WEDNESDAY. THE PROLONGED STORMY PERIOD WILL FAVOR AN
INCREASING RISK OF FLOODING WITH EACH DAY THAT PASSES...WITH
OTHERWISE AN OCCASIONAL PRECIPITATION-LOADED WET MICROBURST FROM
LOOSELY ORGANIZED MULTI-CELL STORM MODES DRIVEN BY GENERALLY 20-25
KTS OF MID LEVEL FLOW. ASIDE FROM THE 00Z/28TH ECMWF...THE CONSENSUS
OF MEDIUM RANGE GUIDANCE...INCLUDING THE 00Z ECMWF ENSEMBLE
MEAN...INDICATES THE PATTERN RETROGRESSION WILL ALLOW THE WESTERN
ATLANTIC SUB-TROPICAL RIDGING TO EXPAND WESTWARD SUFFICIENTLY TO
LESSEN PRECIPITATION CHANCES/COVERAGE - FROM NUMEROUS/WIDESPREAD TO
SCATTERED - OVER EASTERN NC...INCLUDING THE RAH COASTAL PLAIN...BY
MID TO LATE WEEK. HIGHS MOSTLY IN THE MIDDLE 80S...WITH LOWS 70 TO
75.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 AM SATURDAY...
24 HOUR TAF PERIOD:
AN AREA OF SHOWERS AND STORMS ALONG WITH TRAILING STRATIFORM RAIN IS
CURRENTLY MOVING ACROSS EASTERN PORTIONS OF CENTRAL NC... AND SHOULD
BE TO THE EAST OF ALL CENTRAL NC TAF SITES BY 07Z. AT KRDU/KFAY/KRWI
EXPECT WE WILL AGAIN SEE SOME LOW STATUS (IFR/MVFR) DEVELOP AFTER BY
AROUND 08Z OR SO... THEN LIFTING/DISSIPATING AGAIN BY AROUND 14Z OR
SO. FURTHER WEST... A BIT DRIER AIR IS EXPECTED TO PUSH INTO THE
NORTHWEST PIEDMONT (KGSO/KINT). HOWEVER... THE LOW LEVEL AIRMASS IS
EXPECTED TO REMAIN QUITE MOIST... WHICH IS ALLOWING IFR STRATUS TO
DEVELOP. GIVEN THERE WILL BE LITTLE IN THE WAY OF ANY LOW LEVEL
FEATURE TO SCOUR OUT THE LIFR STATUS UNTIL AFTER DAYBREAK... EXPECT
IT WILL CONTINUE UNTIL 14Z OR SO AS WELL. THIS IS CURRENTLY NOT
HANDLED WELL BY THE MODEL GUIDANCE... SO HAVE ELECTED TO START THE
TAF FORECAST WITH A TEMPO GROUP... KEEPING IN MIND THAT WE MAY NEED
TO INSERT A PREVAILING GROUP AND EXTEND IT OUT TO 14Z OR SO.
SHOWERS AND STORMS ARE AGAIN EXPECTED TO DEVELOP AND AFFECT SOUTHERN
AND EASTERN PORTIONS OF CENTRAL NC THIS AFTERNOON AND EVENING (MAYBE
EVEN AS EARLY AS LATE MORNING). WILL INCLUDE VCTS IN THE KFAY AND
KRWI TAF FOR THE AFTERNOON HOURS OF TODAY... WITH NO MENTION AT THIS
TIME FOR THE OTHER SITES. AT KGSO AND KINT... CONFIDENCE WRT SEEING
ANY SHOWERS AND STORMS IS LOWEST... THANKS TO THE DRIER AIR
MENTIONED ABOVE MOVING INTO WESTERN PORTIONS OF THE AREA.
LOOKING BEYOND 06Z SUNDAY...WITH MINIMAL CHANGE IN THE OVERALL
PATTERN OVER THE CONUS... THE RISK FOR DAILY SCATTERED TO NUMEROUS
SUB-VFR SHOWERS AND STORMS (PRIMARILY FROM MID AFTERNOON THROUGH
MIDNIGHT) AND SHALLOW EARLY-MORNING IFR STRATUS IS EXPECTED TO
PERSIST INTO THE MIDDLE OF NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BADGETT
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...BSD/HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
134 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE POTENTIAL FOR HEAVY RAINFALL WILL INCREASE THROUGH THE WEEKEND
AS TROPICAL MOISTURE STREAMS INTO THE CAROLINAS. THE UNSETTLED
WEATHER WILL CONTINUE INTO MUCH OF NEXT WEEK AS AN UNUSUALLY DEEP
UPPER LEVEL LOW SITS WEST OF THE REGION...AND INTERACTS WITH BERMUDA
HIGH PRESSURE OFFSHORE.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1:30 AM SATURDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSIONS FOLLOW:
THE LATEST HRRR RUNS AND UPSTREAM RADAR COMPOSITES SUGGEST POPS
NEED TO BE LOWERED ACROSS MUCH OF MY FORECAST AREA. THE
DEVELOPMENT OF AN MCS ALONG AN EAST-WEST ORIENTED OUTFLOW BOUNDARY
ACROSS THE SOUTHERN PIEDMONT OF NC IS LIKELY RESPONSIBLE FOR THE
RELATIVE LACK OF CONVECTION ACROSS WESTERN AND CENTRAL SOUTH
CAROLINA AS THE STRONG UPWARD MOTION WITHIN THE MCS HAS TO BE
BALANCED BY CORRESPONDING SUBSIDENT MOTION AROUND THE PERIPHERY.
THERE ARE STILL THUNDERSTORMS DIRECTLY ASSOCIATED WITH THE
INCOMING SHORTWAVE DISTURBANCE ALOFT JUST WEST OF ANDERSON
SC...BUT THIS ACTIVITY HAS A LONG WAY TO GO BEFORE IT COULD
CONCEIVABLY AFFECT THE EASTERN CAROLINAS.
THE NORTH CAROLINA MCS SHOULD REMAIN NORTH OF MOST OF MY FORECAST
AREA OVERNIGHT...PERHAPS SCRAPING BY THE NORTHERN PORTIONS OF
ROBESON COUNTY IN A FEW HOURS. THE POPS REMAINING IN THE FORECAST
ARE MAINLY LATE TONIGHT AND ARE FOR THE POSSIBLE DEVELOPMENT OF NEW
CONVECTION WITH THE APPROACHING DISTURBANCE. NO SIGNIFICANT CHANGES
HAVE BEEN MADE TO TEMPERATURE FORECASTS. PREVIOUS DISCUSSION FROM
730 PM FOLLOWS...
A ZONE OF MID-LEVEL DRY AIR BETWEEN TWO SHORTWAVES HAS BROUGHT A
TEMPORARY LULL IN CONVECTIVE ACTIVITY ACROSS THE EASTERN CAROLINAS
TODAY. THIS LULL SHOULD COME TO AN END OVER THE NEXT SEVERAL HOURS
AS A MODEST SHORTWAVE CURRENTLY EXTENDING FROM WESTERN NC INTO
CENTRAL GEORGIA AND ALABAMA PUSHES EAST INTO THE CAROLINAS.
RADAR SHOWS A SQUALL LINE EXTENDING ACROSS NORTH-CENTRAL NORTH
CAROLINA FROM THE VA BORDER SOUTHWARD TO NEAR SOUTHERN PINES. THIS
ACTIVITY IS PROGRESSING MAINLY EAST AND SHOULD MOVE JUST NORTH OF
LUMBERTON BETWEEN 8-9 PM...BUT COULD SCRAPE THE NORTHERN HALVES OF
BLADEN AND PENDER COUNTIES BETWEEN 9-11 PM. WHAT I AM MORE CONCERNED
ABOUT IS NEW CONVECTIVE ACTIVITY DEVELOPING ACROSS WESTERN SOUTH
CAROLINA ASSOCIATED WITH THE MAIN SHORTWAVE ALOFT. LIKE LAST NIGHT
THE HOURLY HRRR RUNS ARE NOT INITIALIZING PERFECTLY BUT MOST PAINT A
STORY OF THUNDERSTORM ACTIVITY INCREASING ACROSS THE PEE DEE REGION
OF EASTERN SOUTH CAROLINA LATE THIS EVENING...SPREADING TO THE COAST
OF BOTH SOUTH AND NORTH CAROLINA AFTER MIDNIGHT. ALTHOUGH MY TIMING
ON THIS CONVECTION IS DIFFERENT FROM THE PREVIOUS FORECAST...MY
12-HOUR POPS ARE NOT SUBSTANTIALLY DIFFERENT: 50-70 PERCENT...
HIGHEST NORTH OF A LINE FROM LAKE CITY TO CONWAY TO WHITEVILLE AND
WILMINGTON.
CONFIDENCE THAT WE WILL HAVE CONVECTIVE ACTIVITY OVERNIGHT IS
BOLSTERED BY NOTING HOW LARGE FORECAST CAPE VALUES ARE ON MODEL
SOUNDINGS. EVEN ACCOUNTING FOR A STABLE SURFACE BOUNDARY LAYER...
LIFTING A PARCEL FROM 925 MB LATE THIS EVENING OVER FLORENCE ON A
RECENT RUC MODEL RUC SHOWS CAPE OVER 2000 J/KG WITH NO CONVECTIVE
INHIBITION. PRECIPITABLE WATER...WHICH HAD FALLEN TO 1.6 TO 1.7
INCHES THIS AFTERNOON...SHOULD RISE BACK TO 2+ INCHES AS THE 850 AND
700 MB LAYER MOISTENS OVERNIGHT.
NO CHANGES HAVE BEEN MADE TO LOW TEMPERATURE FORECASTS...STILL
EXPECTED TO RANGE FROM 73-75 INLAND WITH UPPER 70S NEAR THE COAST.
THIS IS NOT COINCIDENTALLY VERY NEAR OUR CURRENTLY OBSERVED
DEWPOINTS ACROSS THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...JUNE IS GOING TO FINISH PRETTY MUCH HOW IT HAS
BEEN ALL MONTH...WARM...HUMID...AND UNSETTLED. IN FACT...THE WEEKEND
HAS THE POTENTIAL TO BE EVEN WETTER THAN MOST OF THE DAYS THIS
MONTH...AND THE LOCAL CLIMATE STATIONS WILL APPROACH OR EXCEED ALL
TIME-MONTHLY RAINFALL RECORDS FOR JUNE BEFORE THE PERIOD COMES TO AN
END.
HIGHLY ANOMALOUS PATTERN AT 500MB PERSISTS AND AMPLIFIES THROUGH THE
WEEKEND WITH A STRONG RIDGE CENTERED ACROSS THE SOUTHWEST AND A
DEEPENING TROUGH DROPPING ACROSS THE OH VLY. THIS AMPLIFICATION
FORCES A STALL IN THE ATMOSPHERIC RIVER...AND DRIVES THE TROUGH BACK
TO THE SW...CREATING HEIGHT ANOMALIES OF -3 SD`S ACROSS THE TN VLY.
WITH THE DEEPENING TROUGH AXIS DISPLACED WEST OF THE
CAROLINAS...THIS KEEPS DEEP SW FLOW ONGOING IN THIS AREA...AND PWATS
RISE TO 2 INCHES OR MORE...AROUND 2 SD`S ABOVE NORMAL. 5H TROUGH TO
THE WEST WITH DEEP MOISTURE PLUME ACROSS THE CAROLINAS CREATES AN
ENVIRONMENT FAVORABLE FOR HEAVY RAIN...BUT OTHER PARAMETERS AS WELL
SUGGEST A VERY WET PERIOD AHEAD FOR THE WKND.
700MB TROUGH WEST OF THE AREA SHARPENS...KEEPING THE GOMEX WIDE
OPEN AND HELPING TO ADVECT TREMENDOUS THETA-E RIDGING FROM 925MB
THROUGH 700MB. 850MB MOISTURE TRANSPORT VECTORS LENGTHEN AND POINT
RIGHT INTO THE COASTAL CAROLINAS...WITH STREAMLINES SUGGESTING
MORE AND MORE OF THAT GULF TAP. ADDITIONALLY...AS THE TROUGH
SHARPENS...ESPECIALLY SUNDAY...200MB JETTING INCREASES WITH THE
SOUTHEAST ALIGNING BENEATH THE RRQ WHICH WILL COMBINE WITH WEAK
500MB SHORTWAVES TO HELP DRIVE LIFT OVER THE AREA. WHILE
INSTABILITY WILL NOT BE EXTREME...MLCAPE OF 800-1200 J/KG WITH
LI`S AROUND -4...AND WARM CLOUD PROCESSES WILL DOMINATE THANKS TO
13000-14000 FT OF WARM CLOUD DEPTH...ENOUGH LIFT WILL CREATE THE
POTENTIAL FOR ISOLATED WET MICROBURSTS EVEN THOUGH HEAVY RAIN WILL
BE THE PREDOMINANT THREAT BOTH DAYS.
SO THE INGREDIENTS ARE IN PLACE TO SUPPORT AN EXTENDED WET
PERIOD...AND WPC HAS 1-3" OF QPF ACROSS THE AREA...ALTHOUGH ISOLATED
MUCH HIGHER TOTALS ARE LIKELY. THIS WILL OCCUR ACROSS A REGION THAT
HAS SEEN 150-300% OF NORMAL RAINFALL THE PAST TWO WEEKS...SO ANY
HEAVY RAINFALL WILL LIKELY CAUSE SOME FLOODING CONCERNS. AFTER
COLLABORATION WITH SURROUNDING OFFICES...HAVE CHOSEN TO HOLD OFF ON
ANY AREAL FLOOD WATCHES SINCE CONVECTION WILL BE SCATTERED TO
WIDESPREAD...MEANING CWA-BASIN RAINFALL WILL BE HIGHLY VARIABLE.
NEVERTHELESS...WILL NEED TO MONITOR FOR POTENTIAL FLOOD WATCHES AS
THE SYNOPTIC SETUP DEVELOPS IN TIME.
ONE FINAL NOTE ABOUT THE UPCOMING RAINFALL. THE CLIMATE STATIONS OF
FLORENCE, SC AND WILMINGTON, NC ARE BOTH APPROACHING MONTHLY RECORDS
FOR JUNE...AND WOULD NOT BE SURPRISED IF THESE RECORDS ARE ECLIPSED
BEFORE JULY BEGINS:
AT WILMINGTON...10.34" HAS FALLEN SO FAR...2.53" BEHIND THE JUNE
RECORD OF 12.87" (1962).
AT FLORENCE...7.89" HAS FALLEN THIS MONTH...1.30" BEHIND THE RECORD
OF 9.29" (1961).
SW WINDS THROUGH THE PERIOD WILL KEEP THE AIRMASS WARM...BUT TEMPS
WILL LIKELY REMAIN JUST BELOW NORMAL THANKS TO THE WIDESPREAD CLOUD
COVER AND CONVECTION. EXPECT HIGHS IN THE MID/UPR 80S BOTH
AFTNS...BUT WITH SIGNIFICANT VARIABILITY WITHIN SHOWERS/TSTMS. LOWS
AT NIGHT WILL FALL TO 70 OR A FEW DEGREES ABOVE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...HIGHLY AMPLIFIED MID LEVEL PATTERN WILL
CONTINUE THROUGH MOST OF THE EXTENDED PERIOD WHICH MEANS A
CONTINUATION OF THE UNSETTLED CONDITIONS. WPC HAS LIKELY POPS FOR
MONDAY THROUGH WEDNESDAY DURING THE DAYTIME HOURS WITH LOWER
VALUES FOR THE NIGHTTIME HOURS. THIS CERTAINLY SEEMS REASONABLE AS
THE RIVER OF MOISTURE WILL CONTINUE FROM THE SOUTH/SOUTHWEST.
THERE ARE INDICATIONS THE PATTERN WILL BREAK DOWN LATE IN THE
PATTERN WITH SLIGHT RIDGING BUILDING IN WHICH WARRANTS A SLIGHT
DOWNTURN IN POPS. WITH THE PATTERN CHANGING LITTLE...EXPECT
TEMPERATURES TO REMAIN STABLE WITH HIGHS A LITTLE BELOW NORMAL
WITH ALL THE MOISTURE AND OVERNIGHT LOWS A LITTLE ABOVE FOR THE
SAME REASON.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...MCS TO OUR NORTH MAY SPAWN SOME CONVECTION MOVING INTO
LBT AND PERHAPS FLO AN HOUR OR TWO AFTER TAF ISSUANCE. TOWARD
MORNING...DEEP MOISTURE IN PLACE AT ALL TERMINALS...WITH SCATTERED
CONVECTION EXPECTED...WITH ISOLATED THUNDER. CONFIDENCE IS WANING A
BIT HOWEVER AS THE HRRR AND NAM SEEM TO BE BACKING OFF A BIT.
CEILINGS WILL LOWER TO MVFR WITH BRIEF IFR VISIBILITIES IN THE
HEAVIER SHOWERS. SATURDAY...EXPECT INTERMITTENT CONVECTION MOST OF
THE DAY. SOME DRYING ALOFT IS INDICATED AT THE INLAND
TERMINALS...HOWEVER THIS MAY JUST ALLOW MORE HEATING FOR POSSIBLE
AFTERNOON THUNDERSTORMS. AGAIN MVFR CEILINGS ARE EXPECTED THROUGHOUT
MOST OF THE DAY.
EXTENDED OUTLOOK...ISOLATED/SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1:30 AM SATURDAY...NO SIGNIFICANT CHANGES ARE NECESSARY TO
THE FORECAST. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...
BERMUDA HIGH PRESSURE WELL OFFSHORE IS HAVING LIMITED SUCCESS
PUSHING WESTWARD INTO WHAT HAS BECOME (FOR THE SEASON) A VERY STRONG
TROUGH OF LOW PRESSURE INLAND. BAROMETRIC PRESSURES ARE SURPRISINGLY
LOW FOR LATE JUNE...29.67 INCHES HERE IN WILMINGTON AS I TYPE. THE
PATTERN WILL NOT CHANGE OVERNIGHT WITH A HEALTHY FLOW OF SOUTHWEST
WINDS 20-25 KNOTS EXPECTED TO CONTINUE. THIS WIND HAS BUILT SEAS TO
7 FT AT THE FRYING PAN SHOALS BUOY...6 FT AT THE NEW WILMINGTON
"HARBOR" BUOY JUST SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER...AND 5
FT AT THE OCEAN CREST PIER WAVE GAUGE. THE BIGGEST CHANGE TO THE
FORECAST OVERNIGHT WAS TO INCREASE NEARSHORE WAVE HEIGHTS BASED
PRIMARILY ON THE REPORT FROM THE OCEAN CREST PIER REPORT.
SHOWERS JUST INLAND FROM GEORGETOWN DEVELOPED A COUPLE HOURS AGO
ALONG THE SEABREEZE...AND THESE SHOULD LARGELY DISSIPATE OVER THE
NEXT HOUR. AN UPPER LEVEL DISTURBANCE MOVING ACROSS THE WESTERN
CAROLINAS WILL APPROACH THE COASTAL WATERS LATE TONIGHT BRINGING
SCATTERED SHOWERS AND THUNDERSTORMS...MOST NUMEROUS NORTH OF CAPE
FEAR.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...EXTENDED SMALL CRAFT ADVISORY IN PLACE FOR
MUCH OF THE PERIOD...AND THERE IS A GOOD CHANCE IT WILL BE EXTENDED
IN TIME INTO NEXT WEEK. LARGE BERMUDA TYPE HIGH PRESSURE
OFFSHORE...AND AREA OF LOW PRESSURE STALLED INLAND...WILL KEEP A
PINCHED GRADIENT OVER THE WATERS. THIS DRIVES SW WINDS UP TO 20-25
KTS SATURDAY...AND ONLY SLIGHTLY WEAKER ON SUNDAY. SEAS WILL BE
DRIVEN PRIMARILY BY THESE WINDS...AND 4-7 FT WAVE HEIGHTS ARE
EXPECTED THROUGH THE PERIOD. ADDITIONALLY...SCATTERED TO
WIDESPREAD TSTMS BOTH DAYS WILL CREATE HEAVY RAINFALL...CAUSING
SEVERELY RESTRICTED VISIBILITY AT TIMES.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...STEADY STATE CONDITIONS FOR THE COASTAL
COMMUNITY THROUGH THE PERIOD WITH SOUTHERLY WINDS OF 15-20 KNOTS
PROBABLY CLOSER TO THE LOWER END OF THE RANGE. PATTERN WEAKENS
EVER SO SLIGHTLY WEDNESDAY WHICH TRANSLATES TO SLIGHTLY LOWER WIND
SPEEDS. WAVEWATCH GUIDANCE SHOWS 3-5 FEET MONDAY AND TUESDAY SO A
SCEC HEADLINE IS POSSIBLE. SIGNIFICANT SEAS DROP TO 2-4 FEET
WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EDT SUNDAY FOR AMZ250-252-254-
256.
&&
$$
NEAR TERM...REK
AVIATION...REK/DL
MARINE...REK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1213 AM CDT SAT JUN 29 2013
.UPDATE...
ISSUED AT 1212 AM CDT SAT JUN 29 2013
LATEST LOCAL/REGIONAL RADAR SHOWS AN ISOLATED SHOWER JUST SOUTH OF
KJMS WITH ADDITIONAL SHOWERS WORKING SOUTHEAST FROM MANITOBA.
WATER VAPOR IMAGERY SHOWS TWO UPSTREAM SHORTWAVES TO SLIDE
SOUTHEAST INTO CENTRAL NORTH DAKOTA THROUGH 00Z SUNDAY. THE FIRST
IS NEAR BRANDON MANITOBA...WITH THE SECOND JUST WEST OF LAKE
WINNIPEG. NAM/GFS/HRRR ALL GENERATE SPOTTY AREAS OF LIGHT
PRECIPITATION...MAINLY ALONG AND EAST OF HIGHWAY 83 THROUGH THE
PERIOD. MINOR CHANGES TO THE FORECAST OVERNIGHT AS IT WILL BE
MOSTLY DRY...WITH CHANCES OF PRECIPITATION BEGINNING TO INCREASE
BEFORE DAYBREAK IN THE FAR NORTH AND PROGRESS SOUTH DURING THE
LATE MORNING AND AFTERNOON AHEAD OF THE AFOREMENTIONED SHORTWAVES.
UPDATE ISSUED AT 923 PM CDT FRI JUN 28 2013
A MOSAIC OF AREA RADARS SHOWS MUCH OF THE SHOWER / THUNDERSTORM
ACTIVITY HAS DIMINISHED. CAN NOT COMPLETELY RULE OUT A STRAY
SHOWER OVERNIGHT ACROSS PARTS OF NORTH CENTRAL NORTH DAKOTA AS PER
THE 29.00Z NAM...BUT THOSE CHANCES APPEAR LOW ENOUGH TO OMIT FROM
THE FORECAST AT THIS POINT. MADE ONLY MINOR ADJUSTMENTS TO THE
FORECAST WITH MOST WEATHER ELEMENTS ON TRACK.
UPDATE ISSUED AT 642 PM CDT FRI JUN 28 2013
REGIONAL RADAR MOSAIC EARLY THIS EVENING SHOWS ISOLATED SHOWERS /
THUNDERSTORMS MOVING SOUTH ACROSS PARTS OF EASTERN NORTH DAKOTA.
THE STORMS ARE IN THE AREA WITH THE GREATEST INSTABILITY (1000 J/KG)
WHILE INSTABILITY QUICKLY DECREASES IN CENTRAL AND WESTERN NORTH
DAKOTA. THE LATEST RAP FORECAST SHOWS THE INSTABILITY DECREASING
ACROSS THE FAR EASTERN PART OF THE FORECAST AREA THIS
EVENING...AND LATE AFTERNOON / EARLY EVENING VISIBLE SATELLITE
IMAGERY SHOWS CUMULUS QUICKLY DECREASING. WILL CONTINUE TO CARRY A
SMALL CHANCE OF THUNDERSTORMS IN THE FAR EASTERN PART OF THE
FORECAST AREA FOR ANOTHER COUPLE OF HOURS...BUT THE ACTIVITY
SHOULD WANE THIS EVENING. THE REMAINDER OF THE FORECAST LOOKS
GOOD.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 243 PM CDT FRI JUN 28 2013
MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD WILL BE ISOLATED
THUNDERSTORM CHANCES LATE THIS AFTERNOON INTO THIS EVENING AND AGAIN
SATURDAY AFTERNOON AND EVENING.
CURRENTLY...SURFACE HIGH PRESSURE IS SITUATED OVER THE NORTHERN
ROCKIES AND INTO THE NORTHERN HIGH PLAINS...WITH LOW PRESSURE OVER
THE GREAT LAKES REGION. CUMULUS DEVELOPMENT ACROSS WESTERN AND
CENTRAL NORTH DAKOTA WITH A FEW SHOWERS INDICATED ALONG LAKE
SAKAKAWEA.
BEST CAPE REMAINS ACROSS NORTHERN AND EASTERN NORTH DAKOTA...WHILE
BEST SHEAR IS SITUATED OVER SOUTHWEST NORTH DAKOTA. 28 JUNE 12Z NAM
SOUNDINGS INDICATE A VERY DRY ATMOSPHERE AT BISMARCK AND ESPECIALLY
MINOT AND JAMESTOWN WITH ONLY A VERY THIN MOISTURE LAYER. WESTERN
NORTH DAKOTA APPEARS TO HAVE A BETTER CHANCE OF MORE THAN A SHOWER.
CAPE VALUES ARE LIMITED BUT GOOD SPEED SHEAR EXISTS...WITH 50 KNOTS
OF BULK SHEAR CURRENTLY OVER THE SOUTHWEST. WILL KEEP AN EYE ON THE
RADAR AND LATE AFTERNOON/EVENING POPS WILL BE BASED ON LATEST FRAMES.
ANY CONVECTION THAT WOULD DEVELOP WILL QUICKLY DIMINISH THIS EVENING
WITH MAINLY CLEAR SKIES THEREAFTER.
SATURDAY WILL BE A NEAR REPEAT PERFORMANCE OF TODAY. THE EXCEPTIONS
BEING THAT TEMPERATURES WILL BE A LITTLE COOLER AS SHORTWAVE ENERGY
ACTS TO SHARPEN THE BROAD RIDGE OVER THE NORTHERN PLAINS. THIS WILL
ALLOW COOLER TEMPERATURE TO ADVECT SOUTH INTO THE AREA. WINDS WILL
BE LIGHTER AS SURFACE HIGH PRESSURE WILL TRAVERSE THE FORECAST AREA.
AND FINALLY PRECIPITATION CHANCES SHOULD BE LIMITED TO MAINLY FAR
EASTERN PORTIONS OF CENTRAL NORTH DAKOTA...WITH MORE MID LEVEL
MOISTURE AND LESS CAPPING ALOFT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 243 PM CDT FRI JUN 28 2013
THE MAIN UPPER LEVEL PATTERN IN THE LONG TERM BEGINS AS STRONG
MERIDIONAL FLOW...WITH A SHARP RIDGE OVER WESTERN NORTH AMERICA AND
A LARGE LONGWAVE TROUGH OVER THE EASTERN CONUS.
SATURDAY NIGHT THROUGH MONDAY NIGHT SHOULD BE MAINLY DRY - WITH A
FEW PERIODS OF SLIGHT CHANCES OF SHOWERS/THUNDER WITH SOME
INSTABILITY ARISING FROM EITHER A WEAK SHORTWAVE IMPULSE MOVING
THROUGH THE FLOW OR DAYTIME HEATING INSTABILITY THAT MAY BE ENOUGH
TO CAUSE SOME ISOLATED CONVECTION.
THE GFS AND EC ADVERTISE A STRONGER SHORTWAVE MOVING SOUTHWARD IN
THE NORTHERLY UPPER LEVEL FLOW TUESDAY NIGHT/WEDNESDAY...AND A
SURFACE COLD FRONT SHOULD ACCOMPANY THE UPPER SHORTWAVE. THUS
INCREASED CHANCES OF SHOWERS/THUNDERSHOWERS TUESDAY NIGHT AND
WEDNESDAY.
THE MODELS DIVERGE AFTER THIS WITH A PATTERN CHANGE POSSIBLE AS THE
RIDGE/TROUGH STRUCTURE BREAKS DOWN. KEPT MAINLY SLIGHT CHANCES FOR
CONVECTION WEDNESDAY NIGHT THROUGH FRIDAY OF NEXT WEEK.
LOOKING AT HIGHS MAINLY IN THE UPPER 70S AND LOWER 80S THIS TIME
PERIOD WITH LOWS MAINLY IN THE 50S AND LOWER 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1212 AM CDT SAT JUN 29 2013
EXPECT VFR CIGS/VSBYS NEXT 24HR. HOWEVER KMOT/KBIS/KJMS WILL BE
LOCATED IN AN AREA WHERE ISOLATED SHOWERS/THUNDERSTORMS WILL
DEVELOP SATURDAY. FOR NOW HAVE MENTIONED A VCSH AND WILL WATCH THE
RADAR FOR FURTHER DEVELOPMENT BEFORE MOVING TOWARDS MENTIONING
ANYTHING PREDOMINANT. SCT/BKN CUMULUS CLOUDS BETWEEN 5KFT AND
10KFT WILL BE THE RULE AT THE ABOVE MENTIONED AERODROMES...WITH
GENERALLY CLEAR SKIES AND DRY WEATHER FOR KISN/KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...JV
AVIATION...KS
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
407 AM CDT SAT JUN 29 2013
.SHORT TERM...TODAY THROUGH MONDAY
CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A VORT MAX
MOVING SOUTH ACROSS SOUTHERN CANADA READY TO CROSS THE
INTERNATIONAL BORDER. THIS IS THE WAVE THAT WILL MOVE OVER THE
REGION TODAY AND BRING ISO/WDLY SCT SHOWERS AND THUNDERSHOWERS.
MODELS ALSO SHOWING A SUBTLE BACK DOOR COOL FRONT SLIDING
SOUTHWEST INTO THE NORTHEASTERN CWA WHICH WILL HELP TO AID IN
SHOWER DEVELOPMENT. MLCAPE VALUES ARE VERY LOW AND ONLY MAX OUT
AROUND 500 TO 600 J/KG ACROSS THE EASTERN CWA. MOST ALL HI RES
MODELS SHOWING DEVELOPMENT OF SMALL SHOWERS/THUNDERSHOWERS BY
AROUND 18Z AND PUSHES THEM AS FAR WEST AS THE JAMES VALLEY AND
EVEN A TAD FURTHER WEST. EXPECT THAT ANY ACTIVITY WILL DIMINISH
THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
THE REST OF THE SHORT TERM LOOKS RATHER QUITE WITH SURFACE HIGH
PRESSURE IN CONTROL OF THE WEATHER. WINDS WILL BE RATHER LIGHT
WITH PLEASANT TEMPERATURES. CONDITIONS LOOK TO BE DRY WITH PRECIP
CHANCES NOT INCREASING UNTIL LATER ON IN THE EXTENDED PERIOD.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT
THE LONGER RANGE MODEL SOLUTIONS ARE CERTAINLY LESS THAN
CONSISTENT WITH HANDLING UPPER LEVEL FLOW PATTERN EVOLUTION. THE
LATEST INSTALLMENT OF 00Z SOLUTIONS HAS THE MAMMOTH UPPER LEVEL
RIDGE OVER THE WEST FLATTENING OUT BY THURSDAY...WITH STRONGER
WESTERLIES AND EMBEDDED S/W`S MOVING SWIFTLY EASTWARD ACROSS THE
PACIFIC NORTHWEST OVER INTO THE NORTHERN PLAINS BY THE END OF NEXT
WEEK. DOUBTLESS...WHEN THE ALLBLEND POPS GET BOILED DOWN...THERE
WILL BE AT LEAST A COUPLE PERIODS IN THE EXTENDED WITH
PRECIPITATION CHANCES.
AT THIS POINT...TEMPERATURE TRENDS APPEAR TO BE COOLER EARLIER ON
IN THE PERIOD WITH A GRADUAL LOW LEVEL WAA/WARMING TREND HEADING
INTO THURSDAY/FRIDAY.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
WINDS OUT OF THE NORTH/NORTHWEST WILL AGAIN PICK UP BY MID DAY. A
FEW SHOWERS COULD EFFECT KATY/KABR DURING THE AFTERNOON...HOWEVER
PROBABILITY WILL REMAIN LOW AND VFR CONDITIONS ARE EXPECTED TO BE
PREVALENT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...TMT
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1137 PM CDT FRI JUN 28 2013
.AVIATION...
VFR CONDITIONS TO PREVAIL THROUGH THIS TAF ISSUANCE. CONVECTION HAS
STRUGGLED TO MOVE TO THE EAST TO IMPACT THE TERMINALS ACROSS THE
PANHANDLES DUE TO THE UPPER LOW BEING OUT OF THE NORTH. TOMORROW WILL
BE A DIFFERENT CASE. UPPER FLOW IS EXPECTED TO BE OUT OF THE
NORTHWEST SO ANY CONVECTION THAT DEVELOPS ACROSS SE COLORADO OR
EASTERN NEW MEXICO WILL HAVE THE ABILITY TO MOVE INTO THE PANHANDLES.
AS SUCH HAVE INSERTED VCTS INTO THE PREVAILING GROUPS STARTING 2-3Z.
ANY CONVECTION THAT MOVES OVER THE TERMINALS WILL HAVE THE ABILITY TO
DROP CEILINGS AND VISIBILITIES TO MVFR/IFR CATEGORIES.
SURFACE WINDS WILL REMAIN AT OR BELOW 14KTS FROM A SOUTHEAST TO EAST
DIRECTION THROUGH THIS TAF.
&&
.PREV DISCUSSION... /ISSUED 1106 PM CDT FRI JUN 28 2013/
UPDATE...
TSTMS HAVE REMAINED CLOSE TO THE HIGHER TERRAIN OF ERN NM AND ERN CO
THIS EVENING AS STEERING FLOW IS FROM THE NORTH. HAVE LOWERED POPS TO
JUST BELOW MENTIONABLE REST OF TONIGHT ACROSS NWRN ZONES. ALSO
INCREASED CLOUD COVER BASED ON LATEST SATELLITE IMAGERY. UPDATED
PRODUCTS AND GRIDS HAVE BEEN SENT.
ANDRADE
PREV DISCUSSION... /ISSUED 348 PM CDT FRI JUN 28 2013/
SHORT TERM...
AFTERNOON WV SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOWS THE
LARGE UPPER RIDGE SQUARELY CENTERED OVER THE FOUR CORNERS REGION.
WHILE THIS RIDGE WILL LIKELY BRING RECORD HEAT TO THE WESTERN
CONUS...THE PLACEMENT OF THIS RIDGE MEANS THE PANHANDLES WILL SEE A
SHIFT TOWARD WETTER AND COOLER WX CONDITIONS. MEANWHILE THE COLD
FRONT THAT PUSHED THROUGH THE AREA LAST NIGHT HAS SLID INTO SOUTHERN
TX. EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW RESULTED IN COOLER
CONDITIONS ALTHOUGH ITS STILL TOASTY WITH TEMPS THIS AFTERNOON
CLIMBING WELL INTO THE 90S. CONVECTION HAS STARTED TO DEVELOP OVER
THE HIGHER TERRAIN IN NM AND CO WHICH IS TYPICAL IN THIS TYPE OF WX
PATTERN. HOWEVER GIVEN THAT THE UPPER FLOW IS MORE NORTH-
NORTHEASTERLY STORMS WILL HAVE A TOUGH TIME MAKING IT INTO THE
WESTERN TX PANHANDLES. ALTHOUGH INSTABILITY IS IN PLACE ACROSS THE
AREA /PER SPC MESOSCALE ANALYSIS SHOWING AROUND 1000-1500 J/KG SBCAPE
VALUES/ BULK SHEAR IS WEAK SO IF ANY STORMS DO MAKE IT INTO THE
NORTHWESTERN ZONES THEY WILL NOT BE ORGANIZED. HOWEVER PRECIP CHANCES
IMPROVE SAT AS AN UPPER TROUGH OVER THE GREAT LAKES REGION
RETROGRADES INTO THE MIDWEST WHILE THE WESTERN CONUS RIDGE EDGES A
BIT FURTHER TO THE WEST. EXPECT THE UPPER FLOW TO TRANSITION MORE TO
THE NORTHWEST WHICH WOULD FAVOR A GREATER COVERAGE OF STORMS. STORMS
MAY BE MORE ORGANIZED AS WELL OWING TO LARGER VALUES OF CAPE AND
SHEAR. ALTHOUGH SPC HAS KEPT THE AREA OUT OF A SLIGHT RISK FOR SEVERE
STORMS LIKELY DUE TO A LACK OF ANY APPRECIABLE CONVECTIVE INITIATION
MECHANISM...LARGE HAIL AND DAMAGING WIND GUSTS WILL BE THE MAIN
THREATS.
LONG TERM...
THE UPPER TROUGH CONTINUES TO RETROGRADE TOWARD THE OH VALLEY EARLY
NEXT WEEK WHILE THE UPPER RIDGE REMAINS OVER THE WESTERN CONUS. THE
PANHANDLES WILL REMAIN UNDER STOUT NORTHERLY UPPER FLOW ALTHOUGH AT
TIMES...ESPECIALLY EARLY ON IN THE WEEK...PRECIP CHANCES MAY BE
LIMITED DUE TO A MORE NORTHERLY COMPONENT ALOFT. BY WEDNESDAY AND
ESPECIALLY INDEPENDENCE DAY...PRECIP CHANCES LOOK BETTER AS THE UPPER
TROUGH MOVES INTO THE CENTRAL PLAINS WHILE THE UPPER FLOW BACKS
TOWARD THE NORTHWEST. THIS PATTERN LOOKS LIKE IT WILL HOLD TOWARD THE
END OF THE WEEK. GIVEN MEDIUM RANGE MODELS HAVE NOT DIVERGED TOO MUCH
FROM THEIR SOLUTIONS HAVE OPTED TO NOT MAKE TOO MANY CHANGES FOR THIS
PERIOD. BESIDES THE INCREASED RAIN CHANCES...TEMPS WILL CONTINUE TO
COOL WITH HIGHS MAINLY IN THE 80S EXPECTED AREA WIDE. THIS WILL BE A
NICE CONTRAST TO THE HOT WEEK WE`VE HAD.
CLK
FIRE WEATHER...
NEITHER ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
OVER THE NEXT SEVERAL DAYS DUE TO MINIMUM RELATIVE HUMIDITY
VALUES ABOVE 20 PERCENT...PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS...AND 20 FOOT WINDS GENERALLY STAYING UNDER 15 MPH.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
14/02
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1106 PM CDT FRI JUN 28 2013
.UPDATE...
TSTMS HAVE REMAINED CLOSE TO THE HIGHER TERRAIN OF ERN NM AND ERN CO
THIS EVENING AS STEERING FLOW IS FROM THE NORTH. HAVE LOWERED POPS TO
JUST BELOW MENTIONABLE REST OF TONIGHT ACROSS NWRN ZONES. ALSO
INCREASED CLOUD COVER BASED ON LATEST SATELLITE IMAGERY. UPDATED
PRODUCTS AND GRIDS HAVE BEEN SENT.
ANDRADE
&&
.PREV DISCUSSION... /ISSUED 554 PM CDT FRI JUN 28 2013/
AVIATION...
VFR CONDITIONS TO PREVAIL THROUGH THIS TAF ISSUANCE. NORTHWEST UPPER
LEVEL FLOW WILL KEEP THE RISK OF CONVECTION IN AND AROUND THE
TERMINAL BOTH THIS EVENING AND TOMORROW AFTERNOON. CONVECTIVE CHANCES
AT THE TERMINALS THIS EVENING REMAIN TOO LOW TO INSERT INTO
PREVAILING GROUPS AND WILL BE DEPENDENT ON CONVECTION OVER NEW MEXICO
PERSISTING INTO THE PANHANDLES. WILL CONTINUE TO CLOSELY MONITOR THE
CONVECTIVE TRENDS AND WILL MAKE UPDATES AS NEEDED. TOMORROWS CHANCES
LOOK HIGHER THAN TODAYS BUT ARE AT THE VERY END OF THIS TAF ISSUANCE.
PREV DISCUSSION... /ISSUED 348 PM CDT FRI JUN 28 2013/
SHORT TERM...
AFTERNOON WV SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOWS THE
LARGE UPPER RIDGE SQUARELY CENTERED OVER THE FOUR CORNERS REGION.
WHILE THIS RIDGE WILL LIKELY BRING RECORD HEAT TO THE WESTERN
CONUS...THE PLACEMENT OF THIS RIDGE MEANS THE PANHANDLES WILL SEE A
SHIFT TOWARD WETTER AND COOLER WX CONDITIONS. MEANWHILE THE COLD
FRONT THAT PUSHED THROUGH THE AREA LAST NIGHT HAS SLID INTO SOUTHERN
TX. EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW RESULTED IN COOLER
CONDITIONS ALTHOUGH ITS STILL TOASTY WITH TEMPS THIS AFTERNOON
CLIMBING WELL INTO THE 90S. CONVECTION HAS STARTED TO DEVELOP OVER
THE HIGHER TERRAIN IN NM AND CO WHICH IS TYPICAL IN THIS TYPE OF WX
PATTERN. HOWEVER GIVEN THAT THE UPPER FLOW IS MORE NORTH-
NORTHEASTERLY STORMS WILL HAVE A TOUGH TIME MAKING IT INTO THE
WESTERN TX PANHANDLES. ALTHOUGH INSTABILITY IS IN PLACE ACROSS THE
AREA /PER SPC MESOSCALE ANALYSIS SHOWING AROUND 1000-1500 J/KG SBCAPE
VALUES/ BULK SHEAR IS WEAK SO IF ANY STORMS DO MAKE IT INTO THE
NORTHWESTERN ZONES THEY WILL NOT BE ORGANIZED. HOWEVER PRECIP CHANCES
IMPROVE SAT AS AN UPPER TROUGH OVER THE GREAT LAKES REGION
RETROGRADES INTO THE MIDWEST WHILE THE WESTERN CONUS RIDGE EDGES A
BIT FURTHER TO THE WEST. EXPECT THE UPPER FLOW TO TRANSITION MORE TO
THE NORTHWEST WHICH WOULD FAVOR A GREATER COVERAGE OF STORMS. STORMS
MAY BE MORE ORGANIZED AS WELL OWING TO LARGER VALUES OF CAPE AND
SHEAR. ALTHOUGH SPC HAS KEPT THE AREA OUT OF A SLIGHT RISK FOR SEVERE
STORMS LIKELY DUE TO A LACK OF ANY APPRECIABLE CONVECTIVE INITIATION
MECHANISM...LARGE HAIL AND DAMAGING WIND GUSTS WILL BE THE MAIN
THREATS.
LONG TERM...
THE UPPER TROUGH CONTINUES TO RETROGRADE TOWARD THE OH VALLEY EARLY
NEXT WEEK WHILE THE UPPER RIDGE REMAINS OVER THE WESTERN CONUS. THE
PANHANDLES WILL REMAIN UNDER STOUT NORTHERLY UPPER FLOW ALTHOUGH AT
TIMES...ESPECIALLY EARLY ON IN THE WEEK...PRECIP CHANCES MAY BE
LIMITED DUE TO A MORE NORTHERLY COMPONENT ALOFT. BY WEDNESDAY AND
ESPECIALLY INDEPENDENCE DAY...PRECIP CHANCES LOOK BETTER AS THE UPPER
TROUGH MOVES INTO THE CENTRAL PLAINS WHILE THE UPPER FLOW BACKS
TOWARD THE NORTHWEST. THIS PATTERN LOOKS LIKE IT WILL HOLD TOWARD THE
END OF THE WEEK. GIVEN MEDIUM RANGE MODELS HAVE NOT DIVERGED TOO MUCH
FROM THEIR SOLUTIONS HAVE OPTED TO NOT MAKE TOO MANY CHANGES FOR THIS
PERIOD. BESIDES THE INCREASED RAIN CHANCES...TEMPS WILL CONTINUE TO
COOL WITH HIGHS MAINLY IN THE 80S EXPECTED AREA WIDE. THIS WILL BE A
NICE CONTRAST TO THE HOT WEEK WE`VE HAD.
CLK
FIRE WEATHER...
NEITHER ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
OVER THE NEXT SEVERAL DAYS DUE TO MINIMUM RELATIVE HUMIDITY
VALUES ABOVE 20 PERCENT...PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS...AND 20 FOOT WINDS GENERALLY STAYING UNDER 15 MPH.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1030 PM PDT Fri Jun 28 2013
.SYNOPSIS...
Temperatures across the Inland Northwest will warm over the
weekend and reach very hot temperatures early next week. A chance
for thunderstorms will be possible across the region on Saturday
with a small chance of strong to severe thunderstorms Saturday over
the Idaho Panhandle. Temperatures Monday through Wednesday will be
some of the hottest we have seen in several years. Many places
will experience triple digit heat early next week.
&&
.DISCUSSION...
Evening update: We have continued the threat for thunderstorms
along the Cascade Crest for the next few hours. As of
830PM...radar indicated two cells tracking along the western
fringes of the Cascade Crest just west of the northern Chelan
County line. RUC13 indicated this area is carrying over a 1000
J/kg of surface based CAPE with very little CIN. This should be
short-lived with sunset nearing and the lift along the front a few
hours away but we will continue to monitor closely for future
updates.
Otherwise...Very little to update now through 5AM for most
locations as mostly clear skies and light winds dominate. Did
adjust overnight lows to trend warmer then last night as all ASOS
stations currently running 5-10 degrees warmer then yesterday at
this time.
We continue to monitor the thunderstorm potential arriving
early Saturday and continuing through the evening hours. Now that
we have 3 runs of the HRRR (High Resolution Rapid Refresh) model
and the 00z NAM...confidence continues to increase that a cluster
of showers and thunderstorms will spring to life around 12z (5AM)
between southern Chelan County...east toward the Tri-Cities...and
Blue Mtns. This cluster will track northward impacting portions of
the Columbia Basin...East Slopes...Waterville
Plateau...Palouse...and West Plains between 12-18z (5AM-
11AM)...arriving in the Spokane Area around 8AM. It will not be a
continuous line from Chelan county to the Palouse so there is
still some uncertainty exactly which locations will be passed
over. The HRRR has been consistent with a cluster between
Pendleton and Tri- Cities...jogging N/NE into the
Palouse...Columbia Basin...and Spokane Area between 12-16z while
isolated cells develop in the vicinity of the East
Slopes/Wenatchee Area/Waterville Plateau. The 00Z NAM places the
cluster over western reaches of the Basin, Waterville Plateau, and
East Slopes with isolated cells in the vicinity of the Blues and
Palouse which also track north toward Spokane-CDA. Utilizing a
blend of the both...we have increased PoPs slightly into the
20-40% range and will like to see a few more runs of the HRRR and
00z GFS before adjusted further.
Once the front pushes through early Saturday afternoon and the
first round of convection translates through the region, the
forecast becomes quite challenging. Given high dewpoints,
potential for more rainfall Saturday morning and afternoon highs
in the 80`s to lower 90`s, NAM/GFS indicate an impressive amount
of surface based CAPE under a strong CIN layer and there lies the
question, can we break through the CIN. If so, there is the
potential for rapid convection and strong thunderstorms. The
higher terrain of the Idaho Panhandle and mountains of northern WA
may be enough to overcome the CIN but there is little evidence
this will occur in the Basin and lowlands. One exception could be
gusty outflow winds from thunderstorms in the
mountains...descending into the lowlands and creating boundaries
to push through the CIN layer. This is almost impossible to
predict this far out and carrying 20% region-wide was a good idea
from the previous forecast. /sb
&&
.AVIATION...
06Z TAFS: Moisture will begin trickling into the region after
12z arnd the western periphery of a strong ridge of high pressure
centered over the Great Basin. This will interact with a weak
frontal boundary tracking east frm the coastal waters and bring the
potential for elevated showers and thunderstorms across most
terminals btwn 12z-18z. A few stronger storms will be possible
Saturday aftn with peak heating with northern and eastern mountains
carrying the highest threat. Due to strong CIN...we have backed off
on vcts frm the TAF sites however if outflow winds from the mountains
were to spread into the Basin and anything breaks through the cin,
it will intensify rapidly. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 63 89 65 91 68 100 / 10 40 20 10 0 0
Coeur d`Alene 60 89 64 90 65 99 / 10 30 20 10 0 0
Pullman 61 88 62 90 65 100 / 20 30 20 10 10 10
Lewiston 68 95 69 98 69 104 / 20 30 20 10 10 10
Colville 58 92 61 93 63 102 / 10 30 20 10 0 0
Sandpoint 54 89 60 89 60 95 / 0 30 30 10 0 0
Kellogg 61 88 63 88 64 96 / 10 30 30 10 0 10
Moses Lake 66 93 67 97 68 103 / 20 30 10 0 0 10
Wenatchee 68 92 68 96 72 101 / 20 30 10 0 0 0
Omak 66 91 64 96 67 102 / 10 30 10 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory from Noon Monday to 11 PM PDT Tuesday for Central
Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-Lewis
and Southern Nez Perce Counties-Lewiston Area-Northern
Panhandle.
WA...Heat Advisory from Noon Monday to 11 PM PDT Tuesday for East
Slopes Northern Cascades-Lower Garfield and Asotin Counties-
Moses Lake Area-Northeast Mountains-Okanogan Highlands-
Okanogan Valley-Spokane Area-Upper Columbia Basin-
Washington Palouse-Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
858 PM PDT Fri Jun 28 2013
.SYNOPSIS...
Temperatures across the Inland Northwest will warm over the
weekend and reach very hot temperatures early next week. A chance
for thunderstorms will be possible across the region on Saturday
with a small chance of strong to severe thunderstorms Saturday over
the Idaho Panhandle. Temperatures Monday through Wednesday will be
some of the hottest we have seen in several years. Many places
will experience triple digit heat early next week.
&&
.DISCUSSION...
Evening update: We have continued the threat for thunderstorms
along the Cascade Crest for the next few hours. As of
830PM...radar indicated two cells tracking along the western
fringes of the Cascade Crest just west of the northern Chelan
County line. RUC13 indicated this area is carrying over a 1000
J/kg of surface based CAPE with very little CIN. This should be
short-lived with sunset nearing and the lift along the front a few
hours away but we will continue to monitor closely for future
updates.
Otherwise...Very little to update now through 5AM for most
locations as mostly clear skies and light winds dominate. Did
adjust overnight lows to trend warmer then last night as all ASOS
stations currently running 5-10 degrees warmer then yesterday at
this time.
We continue to monitor the thunderstorm potential arriving
early Saturday and continuing through the evening hours. Now that
we have 3 runs of the HRRR (High Resolution Rapid Refresh) model
and the 00z NAM...confidence continues to increase that a cluster
of showers and thunderstorms will spring to life around 12z (5AM)
between southern Chelan County...east toward the Tri-Cities...and
Blue Mtns. This cluster will track northward impacting portions of
the Columbia Basin...East Slopes...Waterville
Plateau...Palouse...and West Plains between 12-18z (5AM-
11AM)...arriving in the Spokane Area around 8AM. It will not be a
continuous line from Chelan county to the Palouse so there is
still some uncertainty exactly which locations will be passed
over. The HRRR has been consistent with a cluster between
Pendleton and Tri- Cities...jogging N/NE into the
Palouse...Columbia Basin...and Spokane Area between 12-16z while
isolated cells develop in the vicinity of the East
Slopes/Wenatchee Area/Waterville Plateau. The 00Z NAM places the
cluster over western reaches of the Basin, Waterville Plateau, and
East Slopes with isolated cells in the vicinity of the Blues and
Palouse which also track north toward Spokane-CDA. Utilizing a
blend of the both...we have increased PoPs slightly into the
20-40% range and will like to see a few more runs of the HRRR and
00z GFS before adjusted further.
Once the front pushes through early Saturday afternoon and the
first round of convection translates through the region, the
forecast becomes quite challenging. Given high dewpoints,
potential for more rainfall Saturday morning and afternoon highs
in the 80`s to lower 90`s, NAM/GFS indicate an impressive amount
of surface based CAPE under a strong CIN layer and there lies the
question, can we break through the CIN. If so, there is the
potential for rapid convection and strong thunderstorms. The
higher terrain of the Idaho Panhandle and mountains of northern WA
may be enough to overcome the CIN but there is little evidence
this will occur in the Basin and lowlands. One exception could be
gusty outflow winds from thunderstorms in the
mountains...descending into the lowlands and creating boundaries
to push through the CIN layer. This is almost impossible to
predict this far out and carrying 20% region-wide was a good idea
from the previous forecast. /sb
&&
.AVIATION...
00Z TAFS: Moisture will begin trickling into the region after
12z arnd the western periphery of a strong ridge of high pressure
centered over the Great Basin. This will interact with a weak
frontal boundary tracking east frm the coastal waters and bring the
potential for elevated showers and thunderstorms across most
terminals btwn 12z-18z with continued uncertainty with the coverage.
A few stronger storms will be possible Saturday aftn with peak
heating with locations east of line from frm KPUW-KCQV carrying the
highest threat. Confidence is even lower regarding placement and
strength of these storms given presence of clouds from morning
convection and really weak forcing contributing to development.
Needless to say...the air mass will be quite unstable and anything
that breaks the cap will become strong quite quickly. If this
occurs, it expected to be on an isolated basis with areas of
southeastern WA and the ID Panhandle most favored attm. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 63 89 65 91 68 100 / 10 40 20 10 0 0
Coeur d`Alene 60 89 64 90 65 99 / 10 30 20 10 0 0
Pullman 61 88 62 90 65 100 / 20 30 20 10 10 10
Lewiston 68 95 69 98 69 104 / 20 30 20 10 10 10
Colville 58 92 61 93 63 102 / 10 30 20 10 0 0
Sandpoint 54 89 60 89 60 95 / 0 30 30 10 0 0
Kellogg 61 88 63 88 64 96 / 10 30 30 10 0 10
Moses Lake 66 93 67 97 68 103 / 20 30 10 0 0 10
Wenatchee 68 92 68 96 72 101 / 20 30 10 0 0 0
Omak 66 91 64 96 67 102 / 10 30 10 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory from Noon Monday to 11 PM PDT Tuesday for Central
Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-Lewis
and Southern Nez Perce Counties-Lewiston Area-Northern
Panhandle.
WA...Heat Advisory from Noon Monday to 11 PM PDT Tuesday for East
Slopes Northern Cascades-Lower Garfield and Asotin Counties-
Moses Lake Area-Northeast Mountains-Okanogan Highlands-
Okanogan Valley-Spokane Area-Upper Columbia Basin-
Washington Palouse-Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1125 PM CDT FRI JUN 28 2013
.UPDATE...
ISSUED AT 839 PM CDT FRI JUN 28 2013
SCATTERED TO OCCASIONAL RAIN SHOWERS CONTINUE ACROSS MUCH OF THE
REGION WITH THE MAIN BAND EXTENDING ALONG A SOUTHEAST TO NORTHWEST
ORIENTED MID LEVEL SHORT WAVE TROUGH THAT RUNS FROM NORTHERN
ILLINOIS TOWARD NORTHERN MINNESOTA. THIS TROUGH WILL NOT SHIFT
MUCH TONIGHT AS A BUILDING RIDGE ACROSS THE ROCKIES WILL BLOCK ANY
MOVEMENT WEST. INSTABILITY HAS BEEN RAPIDLY DECREASING...SO EXPECT
THAT THE THUNDER CHANCES WILL GREATLY DIMINISH OVER THE NEXT FEW
HOURS. DESPITE THIS DECREASING INSTABILITY...SHOWERS HAVE BEEN
SLOW TO DIMINISH IN COVERAGE DUE TO THE MID LEVEL ASCENT PROVIDED
BY THE TROUGH TO GO ALONG WITH ANY REMNANT SURFACE BOUNDARIES LEFT
OVER BY EARLIER CONVECTION. BASED ON THIS...HAVE UPPED THE
PRECIPITATION CHANCES ACROSS SOUTHEAST MINNESOTA TO NORTHEAST IOWA
WHERE IT LOOKS LIKE THIS LIFT WILL SIT OVER TONIGHT...BUT DID
CONTINUE THE DIMINISHING COVERAGE TREND.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 218 PM CDT FRI JUN 28 2013
WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWS A CLOSED LOW NEAR THE
LAKE HURON/EERIE REGION WITH A TROUGH EXTENDING WESTWARD ACROSS
LOWER MI INTO NORTHERN WI/MN. RAP ANALYZING SEVERAL EMBEDDED
POSITIVE VORTICITY MAXIMA WITHIN THIS TROUGH...ADVECTING SOUTHWARD
ACROSS THE AREA. THIS TROUGH/VORTICITY...COMBINED WITH FAIRLY STEEP LOWER
LEVEL LAPSE RATES WAS PRODUCING SCATTERED SHOWER ACTIVITY MAINLY
EAST OF THE MISSISSIPPI RIVER. OTHERWISE...AN EXTENSIVE CUMULUS
FIELD WAS NOTED ACROSS THE REGION UNDER THE COOLER CYCLONIC FLOW
ALOFT WITH SURFACE TEMPERATURES RANGING FROM THE 65-70 DEGREES
ACROSS NORTHERN WI...TO THE NEAR 80 ACROSS NORTHEAST IA/FAR
SOUTHWEST WI. IN ADDITION...BREEZY NORTHWEST WINDS MAKING IT FEEL
LIKE MORE OF AN EARLY AUTUMN DAY ACROSS THE REGION.
LOOK FOR THE MID-LEVEL TROUGH TO CONTINUE DROPPING SOUTHWARD ACROSS
THE AREA TONIGHT...PRODUCING EXTENSIVE CLOUD COVER AND SCATTERED
SHOWER ACTIVITY. LOWS OVERNIGHT EXPECTED TO DROP OFF INTO THE UPPER
50S TO THE LOWER 60S.
COOLER CYCLONIC FLOW TO CONTINUE ACROSS THE AREA ON SATURDAY.
THUS...ANOTHER DAY OF ABUNDANT CLOUD COVER AND SCATTERED SHOWERS CAN
BE EXPECTED. AN ISOLATED RUMBLE OF THUNDER MAY ALSO OCCUR AS 0-1KM
ML MUCAPE PERKS UP INTO THE 400-1000J/KG RANGE BY AFTERNOON. BAY
LATER IN THE AFTERNOON...EXPECTING MOST OF THE CONVECTION TO BE
CONFINED SOUTH MAINLY SOUTH OF I-94 AS THE MID-LEVEL TROUGH AXIS
DROPS FARTHER SOUTH INTO IA/IL AND RIDGING STARTS TO BUILD ACROSS
THE NORTH. OTHERWISE...PLAN ON TEMPERATURES TO BE A COUPLE DEGREES
COOLER THAN FRIDAY...TOPPING OFF IN THE 70-75 RANGE.
THE MID-LEVEL TROUGH WILL CONTINUE TO ROTATE SOUTH OF THE AREA
SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN
PLAINS/MN. AS A RESULT...LOOK FOR A RAPID DIMINISHING OF SHOWER
ACTIVITY ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA WITH CLEARING
SKIES FROM NORTH TO SOUTH AS THE EVENING PROGRESSES. MOSTLY CLEAR
SKIES WILL THEN BE NOTED OVERNIGHT WITH TEMPERATURES COOLING INTO
THE UPPER 40S TO THE MIDDLE 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 218 PM CDT FRI JUN 28 2013
PATTERN REMAINS BASICALLY UNCHANGED FROM SUNDAY THROUGH TUESDAY
NIGHT WITH THE MID-LEVEL TROUGH AXIS EXTENDING FROM THE GREAT LAKES
TO TO THE OHIO RIVER VALLEY WHILE RIDGE OF HIGH PRESSURE CONTROLS
THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGIONS. THIS
KEEPS THE AREA DRY WITH TEMPERATURES REMAINING A FEW DEGREES BELOW
NORMAL. PLAN ON HIGHS IN THE MID/UPPER 70S WITH OVERNIGHT LOWS IN
THE 50S. IT APPEARS THE GFS/ECMWF EVENTUALLY SHOW THE MID-LEVEL
TROUGH FILLING/LIFTING NORTHEAST INTO THE EASTERN GREAT
LAKES/EASTERN ONTARIO BY FRIDAY WITH FLOW BECOMING MORE LAMINAR/HIGH
ZONAL ACROSS CANADA. SO...LOOKS LIKE A SLIGHT CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS WEDNESDAY AND THURSDAY WITH FRIDAY DRY AND
BECOMING WARMER. PLAN ON HIGHS IN THE UPPER 70S ON WEDNESDAY...
WARMING INTO THE 80-85 DEGREE RANGE BY FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1125 PM CDT FRI JUN 28 2013
THE MAIN FOCUS THROUGH SATURDAY NIGHT IS WITH PRECIPITATION TRENDS
AND WHETHER ANY MVFR/IFR CONDITIONS WILL OCCUR. SOME SCATTERED
SHOWERS ARE CURRENTLY MOVING THROUGH THE REGION WITH A MORE
WIDESPREAD BAND NORTH OF THE TWIN CITIES. THIS BAND IS EXPECTED TO
DROP TO THE SOUTH OVERNIGHT WITH IT MORE LIKELY TO HIT RST THAN
LSE. HAVE ADDED A TEMPO GROUP TO ACCOUNT FOR THIS PERIOD OF RAIN
SHOWERS WHEN IT APPEARS THAT SOME MVFR CONDITIONS COULD OCCUR.
AFTER THIS...THERE WILL BE A BRIEF BREAK THIS MORNING BEFORE THE
NEXT TROUGH MOVES IN AND MORE SHOWERS/ISOLATED THUNDERSTORMS
DEVELOP. CONDITIONS ARE AGAIN EXPECTED TO MAINLY BE VFR THOUGH
SOME BRIEF DROPS TO MVFR OR IFR WILL BE POSSIBLE WITH ANY SHOWERS
THAT MOVE THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS NEW YORK NY
745 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE AREA REMAINS POSITIONED BETWEEN A BROAD UPPER TROUGH AND A
BERMUDA HIGH INTO THE BEGINNING OF THE COMING WEEK. THE HIGH
BEGINS TO BUILD TO THE WEST FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SIMILAR STORY ONCE AGAIN TODAY WITH THE REGION REMAINING SITUATED
BETWEEN A BROAD UPPER TROUGH OVER THE GREAT LAKES AND A STRONG
BERMUDA HIGH WELL EAST OVER THE ATLANTIC. THE ASSOCIATED COLD
FRONT WITH THE LATEST SURFACE LOW HAS STALLED OVER THE
NORTHEAST...WITH THE EXPECTATION THIS FRONT THEN REMAINS
STATIONARY OVER THE REGION NOW THROUGH THE WEEKEND. THIS
FRONT...COMBINED WITH MULTIPLE SHORTWAVES ROUNDING THE TROUGH WILL
BRING THE CHC FOR SHOWERS AND THUNDERSTORMS TODAY.
MAIN QUESTION OF THE DAY IS THE TIMING AND COVERAGE OF ANY PCPN.
LATEST HRRR RUN LAGGING ABOUT AN HOUR BEHIND REAL TIME
REFLECTIVITY...NOT DEVELOPING THE PCPN CURRENTLY OFF THE JERSEY
SHORE TILL AROUND 12Z. HOWEVER...DO AGREE WITH THIS PCPN THEN
TRENDING TO THE NORTHEAST AND MOVING ACROSS EASTERN LI AND INTO
SOUTHEASTERN CT. WILL CONTINUE SCT POPS OVER THIS AREA...WITH ISO
POPS OVER THE REST OF THE AREA. PCPN MAINLY SCT SHOWERS WITH
EMBEDDED TSTMS EXPECTED THIS MORNING.
THE MODELS THEN HINT AT DRYING FOR THE REST OF THE MORNING INTO
THE AFTN. 10Z WATER VAPOR IMAGERY SHOWS A SLIGHT DRY SLOT BEHIND
THE VORT MAX MOVING OFF THE MID ATLANTIC COAST WHICH IS PRODUCING
THE PCPN EARLY THIS MORNING. THINKING THIS DRIER AIR MOVES IN AT
LEAST OVER THE WESTERN PARTS OF THE CWA LATER THIS
MORNING...KEEPING FAIRLY DRY CONDITIONS THEN OVER THE AREA...WITH
THE NEXT CHC FOR ANY SHOWERS AND TSTMS BEING LATE AFTN INTO THE
EVENING AS THE NEXT SHORTWAVE AND ASSOCIATED VORT MAX MOVE
THROUGH THE AREA. THE FRONT POSITIONS ITSELF JUST WEST...AND
POSSIBLE CONVERGENCE ALONG THIS BOUNDARY COULD ALSO ASSIST IN
PRODUCING SCT SHOWERS AND TSTMS. INSTABILITY VALUES REMAIN AROUND
1000 J/KG...AND EVEN WITH BULK SHEAR VALUES BETWEEN 20 AND 30
KTS...NOT EXPECTING MUCH IN THE FORM OF ANY STRONG TO SEVERE TSTMS
TODAY.
TEMPS EXPECTED TO BE A FEW DEGREES ABOVE NORMAL TODAY...GENERALLY
IN THE 80S ACROSS THE REGION.
THERE IS A HIGH RISK FOR RIP CURRENTS TODAY THROUGH THIS EVENING
AT THE ATLANTIC BEACHES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SCT SHOWERS AND THUNDERSTORMS POSSIBLE INITIALLY THIS EVENING WITH
THE LAST BIT OF DAYTIME HEATING PRODUCING JUST ENOUGH INSTABILITY
INLAND...ALONG WITH THE PASSING OF THE SHORTWAVE THAT COULD
TRIGGER A FEW MORE SHOWERS AND TSTMS. HOWEVER...WITH THE LOSS OF
THE HEATING...AND WITH SUBSIDENCE BRIEFLY BUILDING IN
OVERNIGHT...THINKING ANY PCPN SHOULD END BY 06Z...AND WE COULD
ACTUALLY SEE A DRY PERIOD UNTIL AT LEAST MID SUNDAY MORNING. HAVE
CONTINUED THE MENTION OF ISO SHOWERS DURING THIS TIME TO ACCOUNT
FOR A RANDOM SHOWER.
THE CHANCE FOR PCPN INCREASES DURING THE DAY SUNDAY WITH A SURFACE
LOW PRESSURE SYSTEM FOLLOWING THE STATIONARY FRONT...AND NEARING
THE NORTHEAST BY SUNDAY NIGHT. WITH THE PERSISTENT SOUTHERLY
FLOW...PW VALUES SHOOT UP...REACHING AROUND 2 INCHES FOR THE DAY
SUNDAY. THIS COULD LEAD TO HEAVIER RAINS WITH ANY STORMS THAT DO
DEVELOP LATE SUN AFTN. THE PASSING OF A SHORTWAVE LATER IN THE DAY
COULD GENERATE JUST ENOUGH FORCING TO PRODUCE SCT
TSTMS...ESPECIALLY OVER THE INLAND AREA WHERE INSTABILITY VALUES
ARE HIGHER BETWEEN 1000-1500 J/KG. ONCE AGAIN THOUGH...INSTABILITY
AND SHEAR REMAIN LOW ENOUGH TO DIMINISH THE THREAT OF ANY SEVERE
WEATHER.
TEMPS HOVER NEAR TO JUST ABOVE NORMAL FOR THE PERIOD. TEMPS MAY
DIFFER BY A FEW DEGREES DEPENDING ON THE EXTENT OF ANY PCPN THAT
FORMS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A BROAD UPPER TROUGH WILL REMAIN ACROSS THE EASTERN UNITED STATES
SUNDAY NIGHT INTO THE BEGINNING OF THE COMING WEEK. 00Z MODEL
GUIDANCE NOW HINTING AT THE TROUGH WEAKENING SOONER AS THE UPPER
LEVEL RIDGE OVER THE ATLANTIC PUSHES WEST TUES INTO WED. WITH
THIS BEING THE FIRST RUN WITH SUCH A SOLUTION...WILL CONTINUE TO
FOLLOW PREVIOUS FORECAST ON TIMING. HOWEVER...IF THE TROUGH DOES
WEAKEN SOONER...THIS COULD RESULT IN A LESS CHC FOR PCPN TUES-
THURS.
SHORTWAVES WILL ROTATE THROUGH THE UPPER TROUGH FROM TIME TO TIME
DURING THE FIRST PART OF THE WEEK. MEANWHILE SURFACE BERMUDA HIGH
REMAINS ANCHORED OFF THE COAST WITH A SURFACE TROUGH AND WEAK
FRONTAL BOUNDARY REMAINING IN THE VICINITY. THE SHORTWAVES WILL
HELP TRIGGER THE SHOWERS AND THUNDERSTORMS ALONG WITH THE SURFACE
TROUGH. DIURNAL INSTABILITY WILL AID THE DEVELOPMENT OF CONVECTION
EACH AFTERNOON AND EVENING. TIMING OF THE SHORT WAVES TOUGH BUT
WILL BE UNSETTLED THROUGH THE PERIOD...SO WILL CARRY CHANCE POPS
WITH THE HIGHEST IN THE AFTERNOON AND EVENING. WITH A TROPICAL
MOISTURE FEED INTO THE REGION HEAVY RAINFALL WILL BE POSSIBLE WITH
ANY OF THE SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER VALUES
REMAIN AROUND 2 INCHES THROUGH SUNDAY INTO WEDNESDAY.
BY THE END OF THE WEEK...UPPER LEVEL TROUGH WEAKENS...WITH THE
RIDGE AND BERMUDA HIGH THEN PUSHING MORE INTO THE NORTHEAST. THIS
WOULD LEAD TO DRIER WEATHER...WITH STILL A SLIGHT CHC OF
AFTN/EVENING TSTMS. TEMPS FAIRLY CONSISTENT DURING THE COMING
WEEK...REMAINING NEAR NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AN AREA OF LIGHT RAIN MOVING OFF THE NJ COAST WILL IMPACT THE
EASTERN THROUGH 13Z...BUT WITH MINIMAL IMPACTS.
PERSISTENCE TYPE OF FORECAST WITH A TROUGH SITUATED OVER THE LOWER
HUDSON VALLEY AND AN ONSHORE S/SW FLOW. AIRMASS HAS DRIED SOME
AND WITH NO SIGNIFICANT FORCING MECHANISM...CONVECTION SHOULD BE
ISOLATED AT BEST ACROSS THE TERMINALS TODAY.
WITH THE EXCEPTION OF KGON...THERE MAY BE SOME PATCHY MVFR FOG UP
TO 13Z...OR EVEN A BRIEF PERIOD IFR/MVFR CIGS WITH THE ONSET OF
DAYTIME HEATING AS THE AIRMASS BEGINS TO MIX. KGON WITH THE
TRAJECTORY OF HIGH DEW POINT AIR ACROSS SOME SLIGHTLY COOLER
WATER...LIKELY TO STAY LIFR THROUGH MUCH OF THE MORNING. THERE IS
SOME UNCERTAINTY AS TO WHETHER OR NOT VFR CONDITIONS DEVELOP.
THERE WAS A 3 HOUR WINDOW ON FRI WHERE CIGS WENT VFR WITH MVFR
VSBYS. LIKELY TO SEE A REPEAT.
A LIGHT S/SW FLOW THIS MORNING WILL INCREASE TO AROUND 10 TO 15
KT BY MIDDAY. GUSTS UP TO 20 KT POSSIBLE.
.OUTLOOK FOR 12Z SUN THROUGH WEDNESDAY...
.SUN-WED...SUB VFR POSSIBLE AT TIMES WITH SCT SHOWERS AND TSTMS.
THERE MAY ALSO BE EPISODES OF STRATUS/FOG AT THE COASTAL TERMINALS
PRODUCING IFR OR LOWER CONDITIONS...WITH THE EMPHASIS ON KGON.
&&
.MARINE...
SCT SHOWERS AND ISO THUNDERSTORMS POSSIBLE OVER MAINLY THE OCEAN
WATERS TODAY...THOUGH MAY REACH THE OTHER WATERS THIS AFTN AND
EVENING. OTHERWISE...WINDS AND WAVES REMAIN ON TRACK FOR THIS
MORNING.
SCA FOR HAZARDOUS SEAS REMAINS UP ON THE OCEAN WATERS THROUGH
SUN...LIKELY TO TO BE EXTENDED IN SUBSEQUENT FORECAST CYCLES.
A LONG FETCH SOUTHERLY FLOW WILL CONTINUE WELL INTO THE UPCOMING
WEEK WITH SEAS ON THE OCEAN WATERS REMAINING AT OR ABOVE 5 FT.
WAVEWATCH GUIDANCE MAY BE OVERDONE BY ABOUT A FOOT OR TWO...
ESPECIALLY SUN AND MON. WINDS ARE EXPECTED TO STAY BELOW SCA
CRITERIA...GENERALLY 10 TO 20 KT...WITH THE UPPER END OF THE RANGE
ACROSS THE OCEAN WATERS.
THERE WILL BE A CHANCE FOR ISOLATED TO SCT CONVECTION ACROSS THE
WATERS THROUGHOUT THE PERIOD.
&&
.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TODAY THROUGH THE
UPCOMING WEEK. ISOLATED HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY LATE SUNDAY INTO TUESDAY...WITH LOCALIZED
FLOODING MAINLY OVER URBAN AND POOR DRAINAGE AREAS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING
OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT SUNDAY
FOR ANZ350-353-355.
&&
$$
SYNOPSIS...SEARS
NEAR TERM...SEARS
SHORT TERM...SEARS
LONG TERM...SEARS/MET
AVIATION...DW
MARINE...SEARS/DW
HYDROLOGY...SEARS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
658 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE AREA REMAINS POSITIONED BETWEEN A BROAD UPPER TROUGH AND A
BERMUDA HIGH INTO THE BEGINNING OF THE COMING WEEK. THE HIGH
BEGINS TO BUILD TO THE WEST FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SIMILAR STORY ONCE AGAIN TODAY WITH THE REGION REMAINING SITUATED
BETWEEN A BROAD UPPER TROUGH OVER THE GREAT LAKES AND A STRONG
BERMUDA HIGH WELL EAST OVER THE ATLANTIC. THE ASSOCIATED COLD
FRONT WITH THE LATEST SURFACE LOW HAS STALLED OVER THE
NORTHEAST...WITH THE EXPECTATION THIS FRONT THEN REMAINS
STATIONARY OVER THE REGION NOW THROUGH THE WEEKEND. THIS
FRONT...COMBINED WITH MULTIPLE SHORTWAVES ROUNDING THE TROUGH WILL
BRING THE CHC FOR SHOWERS AND THUNDERSTORMS TODAY.
MAIN QUESTION OF THE DAY IS THE TIMING AND COVERAGE OF ANY PCPN.
LATEST HRRR RUN LAGGING ABOUT AN HOUR BEHIND REAL TIME
REFLECTIVITY...NOT DEVELOPING THE PCPN CURRENTLY OFF THE JERSEY
SHORE TILL AROUND 12Z. HOWEVER...DO AGREE WITH THIS PCPN THEN
TRENDING TO THE NORTHEAST AND MOVING ACROSS EASTERN LI AND INTO
SOUTHEASTERN CT. WILL CONTINUE SCT POPS OVER THIS AREA...WITH ISO
POPS OVER THE REST OF THE AREA. PCPN MAINLY SCT SHOWERS WITH
EMBEDDED TSTMS EXPECTED THIS MORNING.
THE MODELS THEN HINT AT DRYING FOR THE REST OF THE MORNING INTO
THE AFTN. 10Z WATER VAPOR IMAGERY SHOWS A SLIGHT DRY SLOT BEHIND
THE VORT MAX MOVING OFF THE MID ATLANTIC COAST WHICH IS PRODUCING
THE PCPN EARLY THIS MORNING. THINKING THIS DRIER AIR MOVES IN AT
LEAST OVER THE WESTERN PARTS OF THE CWA LATER THIS
MORNING...KEEPING FAIRLY DRY CONDITIONS THEN OVER THE AREA...WITH
THE NEXT CHC FOR ANY SHOWERS AND TSTMS BEING LATE AFTN INTO THE
EVENING AS THE NEXT SHORTWAVE AND ASSOCIATED VORT MAX MOVE
THROUGH THE AREA. THE FRONT POSITIONS ITSELF JUST WEST...AND
POSSIBLE CONVERGENCE ALONG THIS BOUNDARY COULD ALSO ASSIST IN
PRODUCING SCT SHOWERS AND TSTMS. INSTABILITY VALUES REMAIN AROUND
1000 J/KG...AND EVEN WITH BULK SHEAR VALUES BETWEEN 20 AND 30
KTS...NOT EXPECTING MUCH IN THE FORM OF ANY STRONG TO SEVERE TSTMS
TODAY.
TEMPS EXPECTED TO BE A FEW DEGREES ABOVE NORMAL TODAY...GENERALLY
IN THE 80S ACROSS THE REGION.
THERE IS A HIGH RISK FOR RIP CURRENTS TODAY THROUGH THIS EVENING
AT THE ATLANTIC BEACHES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SCT SHOWERS AND THUNDERSTORMS POSSIBLE INITIALLY THIS EVENING WITH
THE LAST BIT OF DAYTIME HEATING PRODUCING JUST ENOUGH INSTABILITY
INLAND...ALONG WITH THE PASSING OF THE SHORTWAVE THAT COULD
TRIGGER A FEW MORE SHOWERS AND TSTMS. HOWEVER...WITH THE LOSS OF
THE HEATING...AND WITH SUBSIDENCE BRIEFLY BUILDING IN
OVERNIGHT...THINKING ANY PCPN SHOULD END BY 06Z...AND WE COULD
ACTUALLY SEE A DRY PERIOD UNTIL AT LEAST MID SUNDAY MORNING. HAVE
CONTINUED THE MENTION OF ISO SHOWERS DURING THIS TIME TO ACCOUNT
FOR A RANDOM SHOWER.
THE CHANCE FOR PCPN INCREASES DURING THE DAY SUNDAY WITH A SURFACE
LOW PRESSURE SYSTEM FOLLOWING THE STATIONARY FRONT...AND NEARING
THE NORTHEAST BY SUNDAY NIGHT. WITH THE PERSISTENT SOUTHERLY
FLOW...PW VALUES SHOOT UP...REACHING AROUND 2 INCHES FOR THE DAY
SUNDAY. THIS COULD LEAD TO HEAVIER RAINS WITH ANY STORMS THAT DO
DEVELOP LATE SUN AFTN. THE PASSING OF A SHORTWAVE LATER IN THE DAY
COULD GENERATE JUST ENOUGH FORCING TO PRODUCE SCT
TSTMS...ESPECIALLY OVER THE INLAND AREA WHERE INSTABILITY VALUES
ARE HIGHER BETWEEN 1000-1500 J/KG. ONCE AGAIN THOUGH...INSTABILITY
AND SHEAR REMAIN LOW ENOUGH TO DIMINISH THE THREAT OF ANY SEVERE
WEATHER.
TEMPS HOVER NEAR TO JUST ABOVE NORMAL FOR THE PERIOD. TEMPS MAY
DIFFER BY A FEW DEGREES DEPENDING ON THE EXTENT OF ANY PCPN THAT
FORMS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A BROAD UPPER TROUGH WILL REMAIN ACROSS THE EASTERN UNITED STATES
SUNDAY NIGHT INTO THE BEGINNING OF THE COMING WEEK. 00Z MODEL
GUIDANCE NOW HINTING AT THE TROUGH WEAKENING SOONER AS THE UPPER
LEVEL RIDGE OVER THE ATLANTIC PUSHES WEST TUES INTO WED. WITH
THIS BEING THE FIRST RUN WITH SUCH A SOLUTION...WILL CONTINUE TO
FOLLOW PREVIOUS FORECAST ON TIMING. HOWEVER...IF THE TROUGH DOES
WEAKEN SOONER...THIS COULD RESULT IN A LESS CHC FOR PCPN TUES-
THURS.
SHORTWAVES WILL ROTATE THROUGH THE UPPER TROUGH FROM TIME TO TIME
DURING THE FIRST PART OF THE WEEK. MEANWHILE SURFACE BERMUDA HIGH
REMAINS ANCHORED OFF THE COAST WITH A SURFACE TROUGH AND WEAK
FRONTAL BOUNDARY REMAINING IN THE VICINITY. THE SHORTWAVES WILL
HELP TRIGGER THE SHOWERS AND THUNDERSTORMS ALONG WITH THE SURFACE
TROUGH. DIURNAL INSTABILITY WILL AID THE DEVELOPMENT OF CONVECTION
EACH AFTERNOON AND EVENING. TIMING OF THE SHORT WAVES TOUGH BUT
WILL BE UNSETTLED THROUGH THE PERIOD...SO WILL CARRY CHANCE POPS
WITH THE HIGHEST IN THE AFTERNOON AND EVENING. WITH A TROPICAL
MOISTURE FEED INTO THE REGION HEAVY RAINFALL WILL BE POSSIBLE WITH
ANY OF THE SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER VALUES
REMAIN AROUND 2 INCHES THROUGH SUNDAY INTO WEDNESDAY.
BY THE END OF THE WEEK...UPPER LEVEL TROUGH WEAKENS...WITH THE
RIDGE AND BERMUDA HIGH THEN PUSHING MORE INTO THE NORTHEAST. THIS
WOULD LEAD TO DRIER WEATHER...WITH STILL A SLIGHT CHC OF
AFTN/EVENING TSTMS. TEMPS FAIRLY CONSISTENT DURING THE COMING
WEEK...REMAINING NEAR NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
PERSISTENCE TYPE OF FORECAST WITH A TROUGH SITUATED OVER THE LOWER
HUDSON VALLEY AND AN ONSHORE S/SW FLOW. AIRMASS HAS DRIED SOME
AND WITH NO SIGNIFICANT FORCING MECHANISM...CONVECTION SHOULD BE
ISOLATED AT BEST ACROSS THE TERMINALS TODAY.
WITH THE EXCEPTION OF KGON...THERE MAY BE SOME PATCHY MVFR FOG UP
TO 12Z...OR EVEN A BRIEF PERIOD IFR/MVFR CIGS WITH THE ONSET OF
DAYTIME HEATING AS THE AIRMASS BEGINS TO MIX. KGON WITH THE
TRAJECTORY OF HIGH DEW POINT AIR ACROSS SOME SLIGHTLY COOLER
WATER...LIKELY TO STAY LIFR THROUGH MUCH OF THE MORNING. THERE IS
SOME UNCERTAINTY AS TO WHETHER OR NOT VFR CONDITIONS DEVELOP.
THERE WAS A 3 HOUR WINDOW ON FRI WHERE CIGS WENT VFR WITH MVFR
VSBYS. LIKELY TO SEE A REPEAT.
A LIGHT S/SW FLOW EARLY THIS MORNING WILL INCREASE TO AROUND 10
TO 15 KT BY MIDDAY. GUSTS UP TO 20 KT POSSIBLE.
.OUTLOOK FOR 06Z SUN THROUGH WEDNESDAY...
.SUN-WED...SUB VFR POSSIBLE AT TIMES WITH SCT SHOWERS AND TSTMS.
THERE MAY ALSO BE EPISODES OF STRATUS/FOG AT THE COASTAL TERMINALS
PRODUCING IFR OR LOWER CONDITIONS...WITH THE EMPHASIS ON KGON.
&&
.MARINE...
SCT SHOWERS AND ISO THUNDERSTORMS POSSIBLE OVER MAINLY THE OCEAN
WATERS TODAY...THOUGH MAY REACH THE OTHER WATERS THIS AFTN AND
EVENING. OTHERWISE...WINDS AND WAVES REMAIN ON TRACK FOR THIS
MORNING.
SCA FOR HAZARDOUS SEAS REMAINS UP ON THE OCEAN WATERS THROUGH
SUN...LIKELY TO TO BE EXTENDED IN SUBSEQUENT FORECAST CYCLES.
A LONG FETCH SOUTHERLY FLOW WILL CONTINUE WELL INTO THE UPCOMING
WEEK WITH SEAS ON THE OCEAN WATERS REMAINING AT OR ABOVE 5 FT.
WAVEWATCH GUIDANCE MAY BE OVERDONE BY ABOUT A FOOT OR TWO...
ESPECIALLY SUN AND MON. WINDS ARE EXPECTED TO STAY BELOW SCA
CRITERIA...GENERALLY 10 TO 20 KT...WITH THE UPPER END OF THE RANGE
ACROSS THE OCEAN WATERS.
THERE WILL BE A CHANCE FOR ISOLATED TO SCT CONVECTION ACROSS THE
WATERS THROUGHOUT THE PERIOD.
&&
.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TODAY THROUGH THE
UPCOMING WEEK. ISOLATED HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY LATE SUNDAY INTO TUESDAY...WITH LOCALIZED
FLOODING MAINLY OVER URBAN AND POOR DRAINAGE AREAS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING
OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED
HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT SUNDAY
FOR ANZ350-353-355.
&&
$$
SYNOPSIS...SEARS
NEAR TERM...SEARS
SHORT TERM...SEARS
LONG TERM...SEARS/MET
AVIATION...DW
MARINE...SEARS/DW
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1005 AM EDT SAT JUN 29 2013
.UPDATE...
13Z SURFACE ANALYSIS HAS A TROUGH/WEAK FRONT ACROSS NORTHERN GA.
THE MAIN COLD FRONT/WIND SHIFT/DEWPOINT GRADIENT IS STILL BACK
OVER THE MID MISSISSIPPI RIVER VALLEY. SOME CLEARING IS NOTED
ACROSS NORTHERN GA BEHIND THE TROUGH...BUT DO EXPECT DIURNAL CU TO
FILL BACK IN DURING THE HEATING OF THE DAY. STILL COPIOUS CLOUD
COVER ACROSS THE CENTRAL AND SOUTHERN CWFA. BREAKS ARE ALREADY
STARTING TO OCCUR AND SKIES SHOULDN`T BE BKN MUCH LONGER.
WITH THE WIND SHIFT/LOWER DEWPOINTS BACK OVER THE MID MISSISSIPPI
RIVER VALLEY...THERE SHOULDN`T BE MUCH OF A DROP IN DEWPOINTS
UNTIL LATER IN THE AFTERNOON. 10Z RUNS OF THE HRRR BREAK OUT SOME
SHOWERS RIGHT AROUND THE METRO AREA IN THE 16-18Z TIME FRAME.
THINK ISOLD SHOULD BE ABOUT THE EXTENT OF COVERAGE AND THUNDER
WILL BE A STRUGGLE ACROSS THE CENTRAL CWFA. LIKE THE SCT COVERAGE
FURTHER SOUTH. NO CHANGE TO POPS AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 749 AM EDT SAT JUN 29 2013/
UPDATE...
NEAR TERM.
FCST NOT TOO FAR OFF TRACK. JUST WHEN SHRA/TSRA APPEAR TO HAVE
DISSIPATED OVER SRN COUNTIES...ANOTHER ONE DEVELOPS. MODELS STILL
WANT TO ADVECT/MIX DOWN DRIER AIR OVER NORTH AND MUCH OF CENTRAL
GA TODAY. MAY TAKE SOME TIME...BUT APPEARS DRIER AIR WILL LIMIT
INSTABILITY...ESP OVER NORTH GA TODAY. MAY UPDATE POPS/WX ONE LAST
TIME. REST OF FCST LOOKS GOOD.
SNELSON
PREV DISCUSSION... /ISSUED 428 AM EDT SAT JUN 29 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...
PRIMARY CONCERN IN THE SHORT TERM PERIOD IS COVERAGE AND EXTENT OF
SCT TSRA THIS AFTERNOON. INTERESTING UPPER AIR PATTERN. 3 WAVE
NORTHERN HEMISPHERIC PATTERN IN NORTHERN LATITUDES FAVORS
RETROGRADING PROPAGATION WHILE A COUPLE CUTOFF LOWS IN MID AND LOWER
LATITUDES OVER ERN PACIFIC AND CENTRAL ATLANTIC. BROAD UPPER TROUGH
CENTERED OVER THE ERN CONUS PROGGED TO BECOME MORE AMPLIFIED AND
SHORTER WAVELENGTH WHILE SLOWLY RETROGRADING WEST.
ON THE MESOSCALE...DRIER AIR AT SFC HAS PUSHED INTO NE GA THIS
MORNING BUT NOT EXPECTED TO MOVE MUCH FURTHER SOUTH. SHALLOW RICH
MOISTURE COULD MIX OUT THIS AFTERNOON OVER ALL OF NORTH GA...
PROVIDING SMALL RELIEF TO RECENT HUMID CONDITIONS. HOWEVER...MIDDLE
GA WILL REMAIN MOIST WITH CORRESPONDINGLY HIGHER INSTABILITY. NO
WELL DEFINED SFC FRONT BUT WILL BE A MOISTURE AND CLOUD BOUNDARY AND
DIFFERENTIAL DIABATIC HEATING MAY PROVIDE FOCUS FOR STORMS OVER
MIDDLE GA. HIRES MODEL REFLECTIVITY AND NAM/GFS/SREF/ECMWF ALSO
FAVOR THIS AREA FOR CONVECTION. CONVECTION COULD CONTINUE INTO THE
LATE EVENING AND OVERNIGHT THEN FIRE UP AGAIN SUNDAY AFTERNOON AS
UPPER TROF AMPLIFIES AND EVENTUALLY CLOSED LOW DEVELOPS OVER THE MS
VALLEY STATES.
VERY UNUSUAL...AMPLIFIED BLOCKING PATTERN FOR NEAR THE FIRST OF
JULY. WILL HAVE TO WATCH THIS EARLY NEXT WEEK FOR INCREASING AND
ABNORMALLY HIGH MOISTURE CONTENT WITH HEAVY RAIN POTENTIAL.
SNELSON
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THINGS ARE STILL STATUS QUO FOR THE EXTENDED FORECAST. LARGE
UPPER LEVEL TROUGH HAS BEGUN DIGGING INTO THE SOUTHEASTERN STATES
AND WILL CONTINUE THROUGH THE BEGINNING OF NEXT WEEK. THIS TROUGH
DEEPENS OVER THE GREAT LAKE STATES AND PUSHES SOUTH THROUGH
MONDAY/TUESDAY. THIS TROUGH WILL KEEP NORTH AND CENTRAL GA IN
MOIST WEST TO SOUTHWESTERLY FLOW THROUGH DAY 7. THIS WILL KEEP
DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS IN THE FORECAST EVERY
DAY. THERE IS A WEAK COLD FRONT THAT STALLS ACROSS CENTRAL GA
THROUGH THE EXTENDED AND ACTS AS A CATALYST FOR SHOWERS AND
THUNDERSTORMS. WITH VERY LITTLE UPPER LEVEL MOVEMENT...THIS
BOUNDARY IS NOT EXPECTED TO MOVE VERY MUCH AND IT WILL CONTINUE TO
AFFECT CONVECTIVE DEVELOPMENT THROUGH DAY 7.
01
AVIATION...
12Z UPDATE...
STRATUS/FOG IN PLACE OVER MOST NORTH AND SOME CENTRAL GA AIRPORTS.
CIGS ALREADY BEGINNING TO RISE. EXPECT SCT DECK BY 14Z. WITH DRIER
AIR PUSHING ACROSS NORTH GA TODAY...COVERAGE OF TSRA WILL BE LOWER
THAN YESTERDAY BUT NEAR THE SAME OVER AIRPORTS SOUTH AND EAST OF
MACON. HAVE REMOVED TEMPO TS FOR ALL EXCEPT KCSG AND KMCN. WEST
SFC WINDS MAY GUST TO 14-17KTS THIS AFTERNOON.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TSRA LIKELIHOOD.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 69 86 68 / 30 30 50 50
ATLANTA 87 70 85 69 / 30 20 40 40
BLAIRSVILLE 83 62 80 63 / 20 20 40 50
CARTERSVILLE 87 66 85 65 / 20 20 30 40
COLUMBUS 90 72 88 68 / 50 30 40 30
GAINESVILLE 86 69 83 68 / 20 20 40 50
MACON 89 71 87 69 / 50 40 60 40
ROME 88 66 86 65 / 10 20 30 30
PEACHTREE CITY 88 67 85 66 / 30 20 30 30
VIDALIA 88 72 87 73 / 60 50 70 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LISTEMAA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1017 AM EDT SAT JUN 29 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EDT SAT JUN 29 2013
RAIN SHOWERS ARE EXPECTED FROM TIME TO TIME ACROSS CENTRAL INDIANA
THROUGH THE MIDDLE OF NEXT WEEK AS AN UPPER LOW DEVELOPS ACROSS THE
OHIO VALLEY WITHIN A BROAD UPPER TROUGH. A FEW THUNDERSTORMS STORMS
ARE ALSO POSSIBLE. LOOK FOR COOL TEMPERATURES AS AFTERNOON HIGH
TEMPERATURES WILL ONLY BE IN THE 70S THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 950 AM EDT SAT JUN 29 2013
CLOUDS CONTINUE TO DEVELOP AND SPREAD SOUTH ACROSS THE AREA
TODAY...BUT ENOUGH SUN MAY PERSIST ACROSS THE SOUTH TO ALLOW
TEMPERATURES THERE TO GET A LITTLE WARMER THAN PREVIOUSLY THOUGHT.
BUMPED UP TEMPERATURES A BIT IN THE SOUTH.
RAIN IS DEVELOPING ACROSS THE AREA...WITH MORE RAIN UPSTREAM IN
ILLINOIS. HRRR MODEL SHOWING ADDITIONAL RAIN QUICKLY DEVELOPING THIS
AFTERNOON. THUS CONTINUED HIGH POPS DURING THE AFTERNOON
HOURS...JUST CHANGED THE WORDING TO PERIODS OF RAIN TO INDICATE DRY
PERIODS.
PREVIOUS DISCUSSION FOLLOWS...
SURFACE ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER WESTERN
NEW YORK AND BROAD CYCLONIC FLOW ACROSS INDIANA. A TROUGH AXIS
EXTENDED ACROSS SOUTHERN MICHIGAN AND NORTHERN INDIANA TO CENTRAL
ILLINOIS. DEW POINTS WERE STILL RELATIVELY HUMID...IN THE LOWER AND
MIDDLE 60S. WATER VAPOR IMAGERY SHOWS...STRONG RIDGING WAS IN PLACE
ACROSS THE WESTERN UNITED STATES WHILE A DEEP LOW WAS FOUND ACROSS
THE GREAT LAKES AND NORTHEAST. NORTHWEST FLOW WAS SPILLING INTO THE
PLAINS STATES AND OHIO VALLEY BETWEEN THESE TWO SYSTEMS.
FORECAST SOUNDINGS AND TIME HEIGHT BOTH INDICATE PLENTY OF LOWER
LEVEL MOISTURE AVAILABLE TODAY AS THE PREVIOUSLY MENTIONED TROUGH
AXIS PUSHES ACROSS THE FORECAST AREA. TIME HEIGHT SECTIONS
INDICATE BEST LIFT AVAILABLE AROUND 18Z AND FORECAST SOUNDINGS
SHOW DEEP SATURATION NEAR THAT TIME. HOWEVER THUS WILL TREND POPS
HIGHER THAN MAVMOS OR METMOS. AGAIN...A COMPLETE WASHOUT IS NOT
EXPECTED TODAY...HOWEVER MANY AREAS SHOULD SEE PRECIP AS THIS
CYCLONIC FLOW...TROUGH AXIS AND CONVECTIVE TEMPERATURES IN THE
UPPER 60S ALL PROVIDE FAVORABLE CONDITIONS FOR PRECIP.
GIVEN THE EXPECTED CLOUDS AND PRECIPITATION WILL TREND HIGHS AT OR
BELOW MAVMOS VALUES.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 224 AM EDT SAT JUN 29 2013
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND. MAIN CHALLENGE WILL AGAIN BE POPS.
BOTH THE GFS AND THE NAM CONTINUE TO SUGGEST THAT THE BROAD UPPER
LOW WILL REMAIN OVER THE OHIO VALLEY AND INDIANA THROUGH AT LEAST
TUESDAY NIGHT. TIME HEIGHT SECTIONS CONTINUES TO SHOW PLENTIFUL
MOISTURE IN THE LOWER LEVELS. FORECAST SOUNDINGS SHOW CONVECTIVE
TEMPERATURES EACH DAY IN THE UPPER 60S TO AROUND 70...WHICH IS
QUITE REACHABLE. CAPE APPEARS QUITE LIMITED DURING THIS
TIME...WITH VALUES OF LESS THAN 1000 J/KG. THUS WIDESPREAD THUNDER
IS NOT EXPECTED...AN ISOLATED AFTERNOON TSRA CANNOT BE RULED OUT.
NOT CONFIDENT IN TIMING ANY SPECIFIC TROUGH AXIS PASSING AROUND
THE UPPER LOW FLOW TO FOCUS POP AND PRECIP...HOWEVER WILL RAISE
POPS DURING THE AFTERNOONS AS FORCING FROM ANY DAYTIME HEATING
SHOULD AID DEVELOPMENT. WILL STICK CLOSE TO MAVMOS POPS DURING
THE OVERNIGHT PERIODS. AGAIN...A WASHOUT IS NOT EXPECTED THROUGH
THIS PERIOD...BUT RATHER LIGHT...PASSING SHOWERS FROM TIME TO
TIME.
AGAIN...WITH LITTLE CHANGE IN TEMPS AND THE EXPECTED CLOUDS AND
RAIN WILL TREND DAILY HIGHS AT OR BELOW MAVMOS AND TREND DAILY
LOWS WARMER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 224 AM EDT SAT JUN 29 2013
ENSEMBLES INDICATE AN UPPER LOW WILL BE LOCATED OVER THE MIDWEST AT
THE BEGINNING OF THE PERIOD. THIS UPPER LOW IS EXPECTED TO GRADUALLY
WEAKEN AND RETROGRADE A BIT TO THE NORTHWEST AS THE WESTERN ATLANTIC
SUB TROPICAL RIDGE BEGINS TO BUILD BACK INTO THE SOUTHEAST PARTS OF
THE COUNTRY TOWARDS THE MIDDLE AND END OF NEXT WEEK.
WILL CONTINUE WITH CHANCE POPS ON TUESDAY AND WEDNESDAY WITH THE
UPPER LOW NEARBY. BY THURSDAY AND FRIDAY...HEIGHTS ARE EXPECTED TO
RISE...SO THINK PRECIPITATION THREAT WILL DIMINISH BY THURSDAY AND
FRIDAY. WILL LEAVE SOME SMALL CHANCE POPS ON THURSDAY FOR NOW...BUT
IT IS POSSIBLE THEY CAN BE DROPPED AT SOME POINT IN THE FUTURE IF
TRENDS CONTINUE IN THIS DIRECTION.
&&
.AVIATION /DISCUSSION FOR THE 291500Z TAF UPDATE/...
ISSUED AT 1017 AM EDT SAT JUN 29 2013
LOWERED CEILINGS SOME THIS MORNING BASED ON LATEST OBSERVATIONS.
STILL THINK THEY WILL END UP IN THE MVFR CATEGORY ABOVE BKN020 BY
17Z OR SO. SCATTERED SHOWERS WILL BECOME NUMEROUS THIS AFTERNOON
WITH SOME THUNDER LIKELY.
PREVIOUS DISCUSSION FOLLOWS...
UPPER DISTURBANCE CURRENTLY DROPPING SOUTH OVER WISCONSIN IS
EXPECTED TO MOVE INTO THE AREA THIS AFTERNOON. CONVECTIVE PARAMETERS
SUGGEST SCATTERED THUNDERSTORMS WILL ACCOMPANY THIS FEATURE AS IT
PUSHES ACROSS THE TAF SITES...ROUGHLY 291700Z-300100Z. CONVECTION
LOOKS TO BE A LITTLE MORE WIDESPREAD TODAY THAN YESTERDAY GIVEN THE
STRENGTH OF THE UPPER DISTURBANCE AND LOWER CONVECTIVE TEMPERATURES.
BRIEF IFR VISIBILITY RESTRICTIONS AND GUSTY VARIABLE WINDS POSSIBLE
IN THE VICINITY OF ANY CONVECTION. CB BASES AROUND 025.
OTHERWISE...SHOULD BE A PERIOD OF MVFR CEILINGS 015-025 THIS MORNING
BEFORE MIXING OUT AROUND MIDDAY AS SATELLITE LOOPS SHOW RATHER RAPID
DEVELOPMENT OF THESE CEILINGS MOVING SOUTHEAST FROM NORTHERN
ILLINOIS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/50
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
950 AM EDT SAT JUN 29 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EDT SAT JUN 29 2013
RAIN SHOWERS ARE EXPECTED FROM TIME TO TIME ACROSS CENTRAL INDIANA
THROUGH THE MIDDLE OF NEXT WEEK AS AN UPPER LOW DEVELOPS ACROSS THE
OHIO VALLEY WITHIN A BROAD UPPER TROUGH. A FEW THUNDERSTORMS STORMS
ARE ALSO POSSIBLE. LOOK FOR COOL TEMPERATURES AS AFTERNOON HIGH
TEMPERATURES WILL ONLY BE IN THE 70S THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 950 AM EDT SAT JUN 29 2013
CLOUDS CONTINUE TO DEVELOP AND SPREAD SOUTH ACROSS THE AREA
TODAY...BUT ENOUGH SUN MAY PERSIST ACROSS THE SOUTH TO ALLOW
TEMPERATURES THERE TO GET A LITTLE WARMER THAN PREVIOUSLY THOUGHT.
BUMPED UP TEMPERATURES A BIT IN THE SOUTH.
RAIN IS DEVELOPING ACROSS THE AREA...WITH MORE RAIN UPSTREAM IN
ILLINOIS. HRRR MODEL SHOWING ADDITIONAL RAIN QUICKLY DEVELOPING THIS
AFTERNOON. THUS CONTINUED HIGH POPS DURING THE AFTERNOON
HOURS...JUST CHANGED THE WORDING TO PERIODS OF RAIN TO INDICATE DRY
PERIODS.
PREVIOUS DISCUSSION FOLLOWS...
SURFACE ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER WESTERN
NEW YORK AND BROAD CYCLONIC FLOW ACROSS INDIANA. A TROUGH AXIS
EXTENDED ACROSS SOUTHERN MICHIGAN AND NORTHERN INDIANA TO CENTRAL
ILLINOIS. DEW POINTS WERE STILL RELATIVELY HUMID...IN THE LOWER AND
MIDDLE 60S. WATER VAPOR IMAGERY SHOWS...STRONG RIDGING WAS IN PLACE
ACROSS THE WESTERN UNITED STATES WHILE A DEEP LOW WAS FOUND ACROSS
THE GREAT LAKES AND NORTHEAST. NORTHWEST FLOW WAS SPILLING INTO THE
PLAINS STATES AND OHIO VALLEY BETWEEN THESE TWO SYSTEMS.
FORECAST SOUNDINGS AND TIME HEIGHT BOTH INDICATE PLENTY OF LOWER
LEVEL MOISTURE AVAILABLE TODAY AS THE PREVIOUSLY MENTIONED TROUGH
AXIS PUSHES ACROSS THE FORECAST AREA. TIME HEIGHT SECTIONS
INDICATE BEST LIFT AVAILABLE AROUND 18Z AND FORECAST SOUNDINGS
SHOW DEEP SATURATION NEAR THAT TIME. HOWEVER THUS WILL TREND POPS
HIGHER THAN MAVMOS OR METMOS. AGAIN...A COMPLETE WASHOUT IS NOT
EXPECTED TODAY...HOWEVER MANY AREAS SHOULD SEE PRECIP AS THIS
CYCLONIC FLOW...TROUGH AXIS AND CONVECTIVE TEMPERATURES IN THE
UPPER 60S ALL PROVIDE FAVORABLE CONDITIONS FOR PRECIP.
GIVEN THE EXPECTED CLOUDS AND PRECIPITATION WILL TREND HIGHS AT OR
BELOW MAVMOS VALUES.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 224 AM EDT SAT JUN 29 2013
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND. MAIN CHALLENGE WILL AGAIN BE POPS.
BOTH THE GFS AND THE NAM CONTINUE TO SUGGEST THAT THE BROAD UPPER
LOW WILL REMAIN OVER THE OHIO VALLEY AND INDIANA THROUGH AT LEAST
TUESDAY NIGHT. TIME HEIGHT SECTIONS CONTINUES TO SHOW PLENTIFUL
MOISTURE IN THE LOWER LEVELS. FORECAST SOUNDINGS SHOW CONVECTIVE
TEMPERATURES EACH DAY IN THE UPPER 60S TO AROUND 70...WHICH IS
QUITE REACHABLE. CAPE APPEARS QUITE LIMITED DURING THIS
TIME...WITH VALUES OF LESS THAN 1000 J/KG. THUS WIDESPREAD THUNDER
IS NOT EXPECTED...AN ISOLATED AFTERNOON TSRA CANNOT BE RULED OUT.
NOT CONFIDENT IN TIMING ANY SPECIFIC TROUGH AXIS PASSING AROUND
THE UPPER LOW FLOW TO FOCUS POP AND PRECIP...HOWEVER WILL RAISE
POPS DURING THE AFTERNOONS AS FORCING FROM ANY DAYTIME HEATING
SHOULD AID DEVELOPMENT. WILL STICK CLOSE TO MAVMOS POPS DURING
THE OVERNIGHT PERIODS. AGAIN...A WASHOUT IS NOT EXPECTED THROUGH
THIS PERIOD...BUT RATHER LIGHT...PASSING SHOWERS FROM TIME TO
TIME.
AGAIN...WITH LITTLE CHANGE IN TEMPS AND THE EXPECTED CLOUDS AND
RAIN WILL TREND DAILY HIGHS AT OR BELOW MAVMOS AND TREND DAILY
LOWS WARMER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 224 AM EDT SAT JUN 29 2013
ENSEMBLES INDICATE AN UPPER LOW WILL BE LOCATED OVER THE MIDWEST AT
THE BEGINNING OF THE PERIOD. THIS UPPER LOW IS EXPECTED TO GRADUALLY
WEAKEN AND RETROGRADE A BIT TO THE NORTHWEST AS THE WESTERN ATLANTIC
SUB TROPICAL RIDGE BEGINS TO BUILD BACK INTO THE SOUTHEAST PARTS OF
THE COUNTRY TOWARDS THE MIDDLE AND END OF NEXT WEEK.
WILL CONTINUE WITH CHANCE POPS ON TUESDAY AND WEDNESDAY WITH THE
UPPER LOW NEARBY. BY THURSDAY AND FRIDAY...HEIGHTS ARE EXPECTED TO
RISE...SO THINK PRECIPITATION THREAT WILL DIMINISH BY THURSDAY AND
FRIDAY. WILL LEAVE SOME SMALL CHANCE POPS ON THURSDAY FOR NOW...BUT
IT IS POSSIBLE THEY CAN BE DROPPED AT SOME POINT IN THE FUTURE IF
TRENDS CONTINUE IN THIS DIRECTION.
&&
.AVIATION /DISCUSSION FOR THE 291200Z TAFS/...
ISSUED AT 631 AM EDT SAT JUN 29 2013
UPPER DISTURBANCE CURRENTLY DROPPING SOUTH OVER WISCONSIN IS
EXPECTED TO MOVE INTO THE AREA THIS AFTERNOON. CONVECTIVE PARAMETERS
SUGGEST SCATTERED THUNDERSTORMS WILL ACCOMPANY THIS FEATURE AS IT
PUSHES ACROSS THE TAF SITES...ROUGHLY 291700Z-300100Z. CONVECTION
LOOKS TO BE A LITTLE MORE WIDESPREAD TODAY THAN YESTERDAY GIVEN THE
STRENGTH OF THE UPPER DISTURBANCE AND LOWER CONVECTIVE TEMPERATURES.
BRIEF IFR VISIBILITY RESTRICTIONS AND GUSTY VARIABLE WINDS POSSIBLE
IN THE VICINITY OF ANY CONVECTION. CB BASES AROUND 025.
OTHERWISE...SHOULD BE A PERIOD OF MVFR CEILINGS 015-025 THIS MORNING
BEFORE MIXING OUT AROUND MIDDAY AS SATELLITE LOOPS SHOW RATHER RAPID
DEVELOPMENT OF THESE CEILINGS MOVING SOUTHEAST FROM NORTHERN
ILLINOIS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/50
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS JACKSON KY
916 AM EDT SAT JUN 29 2013
.UPDATE...
ISSUED AT 916 AM EDT SAT JUN 29 2013
LATEST HRRR RUN IS SHOWING SCT PRECIPITATION DEVELOPING BY 16Z AND
INCREASING IN COVERAGE THROUGHOUT THE AFTERNOON. WILL CONTINUE WITH
PREVIOUS FORECAST THINKING THAT HIGHEST POTENTIAL FOR CONVECTION WILL
BE IN THE NORTHERN CWA...BUT WENT AHEAD AND BUMPED UP POPS SOONER IN
THE DAY TO COVER ANY SHOWERS OR POSSIBLE THUNDERSTORMS THAT DEVELOP
LATE THIS MORNING. CURRENT SATELLITE IS ALREADY SHOWING SOME SCT CU
DEVELOPING AND MOVING SE...SO EXPECT DEVELOPMENT TO ONLY INCREASE AS
WE GET LATER IN THE MORNING. OTHER FORECAST PARAMETERS SEEM TO BE ON
TRACK SO ONLY MINOR TWEEKS WERE MADE FOR TODAY.
UPDATE ISSUED AT 742 AM EDT SAT JUN 29 2013
UPDATED THE FORECAST TO DELAY THE ONSET OF PRECIPITATION BY A FEW
HOURS BASED ON CURRENT CONDITIONS AND LATEST MODEL TRENDS. THE REST OF
THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 336 AM EDT SAT JUN 29 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM PERIOD. A
UNCHARACTERISTIC UPPER LOW AND TROUGH ARE GOING TO START DROPPING
INTO THE AREA FROM THE NORTH. AT THE SAME TIME THIS TROUGH IS
DROPPING DOWN...A SHORT WAVE WILL BE MOVING AROUND THE TROUGH. THIS
SHOULD PROVIDE AN EXTRA BOOST NEEDED TO KICK OFF SHOWERS AND
THUNDERSTORMS TODAY. THE ONE THING THAT IS HELPING TO RETARD
DEVELOPMENT TODAY IS SOME WARM AIR IN THE MID LAYERS BETWEEN 500
-600 HPA. THIS WILL HELP TO CAP THE STORMS SOMEWHAT AND IS WHAT IS
LIMITING THE COVERAGE TO SCATTERED VERSUS NUMEROUS. WITH THE WEAK
SHEAR AND CAPPING IN THE MID LAYERS...THIS WILL MAKE IT TOUGH TO GET
A THUNDERSTORM TODAY...MUCH LESS A SEVERE ONE. AFTER MIDNIGHT...MOST
CONVECTION SHOULD BE OVER WITH ONLY A STRAY STORM OR TWO POSSIBLE.
ON SUNDAY...THE CAPPING IS NOT AS PRONOUNCED...SO THE CHANCES OF
THUNDERSTORMS WILL BE GREATER...HOWEVER...THEY SHOULD STILL BE ONLY
THE GARDEN VARIETY. TEMPERATURES WILL CONTINUE TO BE BIT LOWER THAN
NORMAL OVER THE NEXT FEW DAYS DUE TO THE UPPER TROUGH DROPPING
SOUTH. WENT ABOUT ONE DEGREE COOLER THAN THE MODEL BLEND.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 336 AM EDT SAT JUN 29 2013
AN UPPER LEVEL LOW WILL SPIN JUST TO OUR WEST EARLY IN THE
PERIOD...BEFORE LIFTING TO THE NORTH AS A LARGE RIDGE OF HIGH
PRESSURE BACKS TO THE EAST COAST TO END THE PERIOD. THIS PATTERN
WILL CAUSE A DEEP SOUTHERLY FLOW TO BECOME ENTRENCHED OVER OUR
REGION SUPPLYING PLENTY OF MOISTURE FOR DAILY SHOWERS AND
THUNDERSTORMS. THE CONVECTION WILL LIKELY BE DIURNALLY BASED WITH
WEAK TRIGGERS SO WILL ADVERTISE POPS AND SKY COVER PEAKING DURING
THE MID TO LATE AFTERNOON HOURS EACH DAY. WILL DECREASE RAIN CHANCES
A LITTLE BIT TOWARD THE END OF THE PERIOD AS THE UPPER LOW MOVES
AWAY FROM THE AREA...ALTHOUGH MOISTURE WILL REMAIN PLENTIFUL.
TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY BELOW SEASONAL NORMS...
INCHING UP A TAD LATE IN THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 742 AM EDT SAT JUN 29 2013
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. EXCEPTION WOULD
BE ANY SHOWERS OR THUNDERSTORMS THAT HAPPEN TO PASS OVER ANY OF OUR
TERMINALS THIS AFTERNOON AND THE DEEP VALLEYS TOMORROW MORNING THAT
WILL HAVE SOME VLIFR FOG. THE TAF STATIONS SHOULD NOT BE SEEING ANY
FOG THIS MORNING. SOME PATCHY FOG WILL BE POSSIBLE AGAIN AFTER 4Z IN
THE VALLEYS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...JJ
LONG TERM...ABE
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1030 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE COMBINATION OF A WARM AND HUMID AIR MASS OVER THE REGION AND A
LOW PRESSURE TROUGH OVER THE EASTERN STATES WILL RESULT IN UNSETTLED
WEATHER OVER OUR REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1030 AM SATURDAY...
REST OF TODAY THROUGH TONIGHT: LATEST DATA SUPPORTS CONTINUED HIGH
RAIN CHANCES IN THE EAST THIS AFTERNOON INTO TONIGHT... BUT THE
WESTERN HALF OF CENTRAL NC MAY GET A CHANCE TO DRY OUT A LITTLE
TODAY BEFORE MORE RAINS ARRIVE IN THE COMING FEW DAYS. LATEST
SATELLITE AND RADAR IMAGERY SHOWS A BATCH OF SHALLOW LIGHT SHOWERS
OVER NW NC/SW VA FORCED IN PART BY WEAK UPPER DIVERGENCE AND MID
LEVEL DPVA ALONG THE 700 MB FRONT... WHILE ELSEWHERE... MID CLOUDS
STREAKING OFF OF LAST NIGHT`S MCS OVER SRN MS/AL STREAM OVER THE
SOUTHEAST HALF OF THE CWA WHERE LOW LEVEL MOISTURE TRANSPORT REMAINS
ELEVATED SOUTH AND EAST OF THE 850 MB FRONT... AND WHERE ISOLATED
MODERATE SHOWERS PERSIST. THE 850 MB FRONT MADE GOOD EASTWARD
PROGRESS OVERNIGHT WITH THE LOW LEVELS COOLING MARKEDLY... DENOTED
BY 850 MB TEMPS DROPPING FROM 20C TO 16C AT GSO FROM 00Z TO 12Z...
WHICH IS SIGNIFICANT COOLING ESPECIALLY FOR THIS TIME OF YEAR. PW
VALUES HAVE DIPPED AS WELL IN THE WEST WITH READINGS BACK DOWN TO
SEASONAL NORMALS AT GSO NOTED IN THE SOUNDING AND BLENDED TPW
IMAGERY. BUT PW REMAINS HIGH AT 1.8-2.0 INCHES EAST OF THE 850 MB
FRONT... MAINLY ALONG/EAST OF I-95... WHERE PASSAGE OF MID LEVEL
PERTURBATIONS WILL BOOST WHATEVER ASCENT CAN BE ACHIEVED VIA THE
INCREASING BUOYANCY THROUGH THE DAY. THE PRESENCE OF THE MID LEVEL
CLOUDS SHOULD HELP CURB INSTABILITY A BIT... BUT STILL EXPECT MLCAPE
VALUES OF 1500-2000 J/KG ACCORDING TO RECENT RAP RUNS. DEEP LAYER
SHEAR HERE WILL BE LOWER THAN TO THE NORTHWEST... JUST 20-25 KTS...
SO THIS MAY LIMIT ORGANIZATION SOMEWHAT. WILL HAVE LIKELY POPS SE OF
RALEIGH TRENDING TO LOW CHANCES FROM RALEIGH TO THE NW FOR THE REST
OF THE DAYLIGHT HOURS. TEMPS ARE RUNNING A FEW DEGREES BELOW
FORECAST PACE ESPECIALLY THROUGH THE CENTRAL CWA WHERE MID CLOUDS
HAVE HINDERED HEATING. WILL TRIM A DEGREE OR SO OFF HIGHS IN THE
CENTRAL/SE CWA... WITH 84-89 AREAWIDE. THE VORTICITY MAX DROPPING
SOUTHWARD OVER LAKE MICHIGAN INTO IL/IN LATER TODAY WILL LEAD TO
OVERALL LONGWAVE TROUGH AMPLIFICATION TO OUR WEST AND SLOWLY BACKING
WINDS ALOFT OVER NC TONIGHT. INSTABILITY WANES AFTER SUNSET WITH THE
RAP SHOWING MLCAPE UNDER 800 J/KG OVERNIGHT AND LARGE SCALE MODELS
SUGGESTING LITTLE RECOVERY OF HIGHER PW BACK WESTWARD UNTIL LATE
TONIGHT... SO WILL TREND TO LOW CHANCES OF LINGERING SHOWERS
OVERNIGHT MAINLY EAST. LOWS 69-73. -GIH
SUNDAY:
AS ENERGY ALOFT DIVES SOUTHWARD ALONG THE BACKSIDE OF THE TROUGH
ACROSS THE EASTERN HALF OF THE COUNTRY SUNDAY MORNING/SUNDAY... DEEP
SOUTH-SOUTHWESTERLY FLOW WILL INCREASE ACROSS OUR AREA... PUMPING
MORE WARM MOIST AIR INTO CENTRAL NC. THIS WILL LEAD TO LOTS OF
CLOUDS AND INCREASED CONVECTIVE CHANCES. CHANCES OF SHOWERS AND
STORMS WILL BE TIED TO SUBTLE DISTURBANCES MOVING THROUGH THE
SOUTH-SOUTHWESTERLY FLOW ALOFT ALONG WITH AFTERNOON HEATING. MODEL
GUIDANCE CONTINUES TO DEVELOP SCATTERED TO NUMEROUS SHOWERS AND
STORMS ON SUNDAY. THUS... WILL CONTINUE TO ADVERTISE LIKELY POPS ON
SUNDAY AFTERNOON INTO THE EVENING. THE MAIN THREAT WITH THESE
SHOWERS AND STORMS WILL LIKELY BE HEAVY RAIN AND FLASH FLOODING AS
PW`S ARE EXPECTED TO INCREASE TO AROUND THE 2" RANGE. HOWEVER...
DEEP LAYER SHEAR IS EXPECTED TO BE IN THE 25 TO 35 KT RANGE....
THOUGH INSTABILITY MAY BE HAMPERED A BIT BY THE AMOUNT OF CLOUD
COVER. THUS... GIVEN THE POSSIBLE MULTI-CELLAR BAND/CLUSTERS OF
SHOWERS AND STORMS... EXPECT WE MAY HAVE AT LEAST A SMALL DAMAGING
WIND THREAT. EXPECT HIGH TEMPS WILL BE IN THE 84-87 DEGREE RANGE
THANKS TO THE INCREASE IN MOISTURE/STORMS/CLOUDS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 308 AM SATURDAY...
AN ABNORMALLY DEEP UPPER LEVEL TROUGH OVER THE LOWER OH-TN VALLEYS
WILL MAINTAIN A DEEP SLY FLOW OVER THE CAROLINAS SUNDAY NIGHT
THROUGH TUESDAY. THIS FLOW WILL SUPPLY OUR REGION WITH PLENTY OF
WARM TROPICAL AIR AS PRECIP WATER VALUES PROJECTED TO RANGE IN THE
2-2.25 INCH THROUGH THE PERIOD. HEATING OF THIS AIR MASS ALONG WITH
A VORTICITY AXIS EXPECTED TO EXTEND SOUTH-TO-NORTH ACROSS CENTRAL NC
WILL CAUSE NUMEROUS-WIDESPREAD SHOWERS AND
THUNDERSTORMS...ESPECIALLY IN THE AFTERNOON AND EVENING HOURS. DUE
TO THE ORIENTATION OF THE WIND FIELD AND THE MOISTURE LADEN AIR MASS
IN PLACE...SHOWERS AND T-STORMS MAY MOVE REPEATEDLY ACROSS THE SAME
LOCATION. THIS OCCURRENCE MAY LEAD TO FLASH FLOODING...ESPECIALLY IN
URBAN AREAS. PLAN TO CONTINUE TO HIGHLIGHT THIS THREAT IN THE HWO.
OVERNIGHT TEMPS WILL CONTINUE TO BE MUGGY WITH MINIMUM TEMPS IN THE
UPPER 60S-LOWER 70S. EXTENSIVE CLOUD COVERAGE AND ABUNDANT SHOWERS
WILL RESULT IN HIGH TEMPS 3-5 DEGREES BELOW NORMAL. MAX TEMPS
GENERALLY IN THE MID 80S.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 308 AM SATURDAY...
MEDIUM RANGE GUIDANCE CONTINUE TO ADVERTISE A GRADUAL WESTWARD SHIFT
OF THE MAIN MOISTURE PLUME AND ATTENDANT SHEAR AXIS AS SUB-TROPICAL
RIDGE EXTENDS ITS INFLUENCE ONTO THE EASTERN SEABOARD. THIS WOULD
LEAD TO A GRADUAL DECREASE IN CONVECTIVE COVERAGE AS THE AIR MASS
DRIES OUT AND A MID LEVEL INVERSION ASSOCIATED WITH THE BUILDING
HEIGHTS ALOFT CAPS THE ATMOSPHERE. PLAN TO MAINTAIN THE PREVIOUS
FORECAST OF DECREASE POPS..MOST NOTABLE THURSDAY INTO FRIDAY. THE
DECREASE IN CONVECTIVE COVERAGE AND EXTENDED PERIODS OF SUN WILL
WARM AFTERNOON TEMPS BACK INTO THE UPPER 80S TO AROUND 90 BY THE END
OF THE WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 750 AM SATURDAY...
24 HOUR TAF PERIOD:
AREAS OF LIFR/IFR FOG HAVE DEVELOPED THIS MORNING ACROSS THE
PIEDMONT AND COASTAL PLAIN (KGSO/KIN/KRDU/KRWI)... WITH PATCHY MVFR
CIGS FURTHER SOUTH ACROSS THE SANDHILLS (KFAY). EXPECT THIS CIGS TO
GENERALLY LIFT TO VFR BY MID TO LATE MORNING AT THE LATEST... WITH
PERHAPS KFAY HANGING ONTO SUB-VFR CIGS THE LONGEST... WHERE LOW
LEVEL MOISTURE IS THE GREATEST. WRT PRECIP CHANCES TODAY... EXPECT
THE GREATEST CHANCE FOR SHOWERS AND STORMS WILL BE ACROSS THE FAR
SOUTHEAST/EAST AND POSSIBLY THE NORTHWEST. FOR NOW WILL GO WITH VCSH
AT KFAY ONLY... WHERE CONFIDENCE IS THE HIGHEST FOR SHOWERS AND
STORMS... AS MOISTURE IS THE GREATEST ACROSS OUR SOUTHEAST.
ALTHOUGH... EXPECT WE WILL SEE AT LEAST ISOLATED TO SCATTERED ACROSS
ALL OF CENTRAL NC THIS AFTERNOON INTO THE EVENING.
SUB-VFR CONDITIONS ARE LIKELY TO DEVELOP AGAIN TONIGHT...IN THE
PRE-DAWN HOURS. HOWEVER... GIVEN THE UNCERTAINTY IN PRECIP TODAY...
WILL JUST INTRODUCE A SCATTERED CLOUDS IN THE 003-008 RANGE AT 09Z
SUNDAY.
LOOKING BEYOND 12Z SUNDAY... DAILY SCATTERED TO NUMEROUS SUB-VFR
SHOWERS AND STORMS (PRIMARILY FROM MID AFTERNOON THROUGH MIDNIGHT)
AND SHALLOW EARLY-MORNING IFR STRATUS IS EXPECTED TO PERSIST INTO
THE MIDDLE OF NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BSD/HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
639 AM EDT SAT JUN 29 2013
.SYNOPSIS...
THE POTENTIAL FOR HEAVY RAINFALL WILL INCREASE THROUGH THE WEEKEND
AS TROPICAL MOISTURE STREAMS INTO THE CAROLINAS. THE UNSETTLED
WEATHER WILL CONTINUE INTO MID WEEK AS AN UNUSUALLY DEEP UPPER
LEVEL TROUGH SITS WEST OF THE REGION...AND INTERACTS WITH BERMUDA
HIGH PRESSURE OFFSHORE. THE PATTERN WILL FINALLY BREAK COME
THURSDAY AS HIGH PRESSURE SHIFTS WESTWARD WITH MORE LIMITED SHOWER
ACTIVITY EXPECTED THROUGH THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 6:30 AM SATURDAY...PREVIOUS NEAR-TERM DISCUSSION WAS POSTED
IN ERROR. THE CORRECT NEAR-TERM DISCUSSION FOLLOWS BELOW:
INCREASING CHANCES FOR SIGNIFICANT AND POSSIBLY HEAVY RAINFALL
TODAY AND TONIGHT AS AN UPPER TROUGH INTENSIFIES OVER THE EASTERN
CONUS. COMBINATION OF THE H/5 TOUGH ALOFT AND A SURFACE PATTERN
CONSISTING OF A STALLED FRONT TO OUR WEST AND THE BERMUDA HIGH TO
OUR EAST WILL CONTINUE TO ADVECT IN A DEEPLY MOIST AND WARM
AIRMASS. P/W VALUES WILL EQUAL OR EXCEED 2 INCHES THROUGH THE NEAR
TERM AND DEWPOINTS IN THE 70S WILL MAKE FOR ANOTHER UNCOMFORTABLY
HUMID DAY.
BIGGEST THREAT TODAY WILL BE FROM LOCALIZED FLOODING PRODUCED BY
HEAVY RAIN AND ALREADY SATURATED SOILS. MODEL SOUNDINGS SHOW A
MARGINALLY UNSTABLE AND VERY MOIST AIRMASS CAPABLE OF PRODUCING
PERIODS OF TORRENTIAL RAINFALL. ALTHOUGH SHOWERS COULD POP UP AT ANY
TIME...EXPECT BEST TIME FOR SIGNIFICANT STORM INITIATION STARTING
THIS AFTERNOON AS DAYTIME HEATING WORKS TO FURTHER DESTABILIZE THE
COLUMN. ANY PASSING UPPER DISTURBANCES WILL FURTHER ENHANCE
CHANCES FOR HEAVY RAIN.
LEANED TOWARDS THE TOP-PERFORMING GFS MOS FOR TODAYS
TEMPERATURES...WITH HIGHS IN THE UPPER 80S MOST PLACES AND MID 80S
AT THE COAST. LOWS WILL BE LOWER TO MID 70S MOST LOCATIONS.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...VERY WARM AND HUMID AIR MASS WILL REMAIN
IN PLACE IN SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE TO OUR
EAST. MID TO UPPER TROUGH WILL DIG DOWN FROM THE GREAT LAKES INTO
THE LOWER MISSISSIPPI VALLEY THROUGH EARLY NEXT WEEK. LOCAL AREA
WILL REMAIN IN BETWEEN RIDGE TO THE EAST AND THIS TROUGH TO THE
WEST. THIS WILL PRODUCE A DEEP SOUTHERLY FLOW OF MOIST TROPICAL
AIR. LOW LEVEL FLOW WILL REACH UP TO 30 TO 40 KTS PUMPING THIS
WARM MOIST AIR IN. PCP WATER VALUES WILL BE OVER 2 INCHES THROUGH
MUCH OF THE PERIOD. PLENTY OF SHORTWAVE ENERGY WILL RIDE AROUND
THIS HIGHLY AMPLIFIED TROUGH AND DECENT JET DYNAMICS WILL BE IN
PLACE SUNDAY THROUGH MONDAY. MOISTURE PROFILES AND SOUNDINGS SHOW
VERY DEEP LAYER MOISTURE THROUGH THE COLUMN. OVERALL EXPECT A VERY
WET PERIOD WITH SHOWERS AND THUNDERSTORMS AT ANY TIME. WITH DEEP
MOISTURE AND LIFT EXPECT TORRENTIAL RAIN IN THUNDERSTORMS AND
POSSIBILITY OF WET MICROBURSTS TO CREATE A DAMAGING WIND THREAT.
JUNE MAY FINISH UP WITH RECORD OR NEAR RECORD RAINFALL FOR THE
MONTH.
IN WILMINGTON...10.34 INCHES OF RAIN HAS FALLEN THIS MONTH WHICH
IS 2.53 INCHES UNDER THE JUNE RECORD OF 12.87" (1962).
IN FLORENCE...7.89 INCHES OF RAIN HAS FALLEN THIS MONTH WHICH IS
1.30INCHES UNDER THE RECORD OF 9.29" (1961).
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...DEEP SOUTHERLY FLOW OF WARM AND MOIST
AIR WILL CONTINUE THROUGH TUES INTO WEDNESDAY BUT THE MID TO UPPER
TROUGH WILL LIFT OFF TO THE NORTHEAST AS STRONG RIDGE BUILDS IN
FROM THE EAST. HIGH PRESSURE FROM THE SURFACE UP THROUGH THE MID
TO UPPER LEVELS WILL BUILD WESTWARD PROVIDING INCREASED SUBSIDENCE
AND DRYING THROUGH THE LOW TO MID LEVELS OF THE ATMOSPHERE.
ALTHOUGH THE WARM AND HUMID AIR MASS WILL REMAIN AT THE
SURFACE...THE SUBSIDENCE AND DRYING ALOFT WILL LIMIT THE
CONVECTIVE POTENTIAL. MOISTURE PROFILES SHOW A VERY DRY ATMOSPHERE
FROM ABOUT 4K FT UPWARDS. BASICALLY EXPECT FOG OVERNIGHT INTO
EARLY MORNING HOURS AS DEWPOINT TEMPS CONTINUE UP AROUND 70 AND
BETTER RADIATIONAL COOLING POTENTIAL EXISTS. THEREFORE MAY SEE LOW
CLOUDS IN THE MORNING LIFTING INTO STRATOCU...BUT EXPECT MORE
LIMITED SHWR ACTIVITY THURS INTO NEXT WEEKEND WITH INCREASED
SUBSIDENCE AND DRY AIR ALOFT.
WARM AND HUMID CONDITIONS WILL PERSIST WITH WINDS BACKING AROUND
TO THE SOUTHEAST AND LIGHTENING UP AS GRADIENT WEAKENS AS CENTER
OF HIGH MOVES CLOSER. TEMPS RUNNING RIGHT AROUND NORMAL FOR THIS
TIME OF YEAR WITH HIGHS PUSHING 90 AND LOWS IN THE LOWER 70S.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...MCS TO OUR NORTH MAY SPAWN SOME CONVECTION MOVING INTO
LBT AND PERHAPS FLO AN HOUR OR TWO AFTER TAF ISSUANCE. TOWARD
MORNING...DEEP MOISTURE IN PLACE AT ALL TERMINALS...WITH SCATTERED
CONVECTION EXPECTED...WITH ISOLATED THUNDER. CONFIDENCE IS WANING A
BIT HOWEVER AS THE HRRR AND NAM SEEM TO BE BACKING OFF A BIT.
CEILINGS WILL LOWER TO MVFR WITH BRIEF IFR VISIBILITIES IN THE
HEAVIER SHOWERS. SATURDAY...EXPECT INTERMITTENT CONVECTION MOST OF
THE DAY. SOME DRYING ALOFT IS INDICATED AT THE INLAND
TERMINALS...HOWEVER THIS MAY JUST ALLOW MORE HEATING FOR POSSIBLE
AFTERNOON THUNDERSTORMS. AGAIN MVFR CEILINGS ARE EXPECTED THROUGHOUT
MOST OF THE DAY.
EXTENDED OUTLOOK...ISOLATED/SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY WITH BRIEF LOCALIZED PERIODS OF
MVFR/IFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:30 AM SATURDAY...PREVIOUS NEAR-TERM DISCUSSION WAS POSTED
IN ERROR. THE CORRECT NEAR-TERM DISCUSSION FOLLOWS BELOW:
SMALL CRAFT ADVISORY CONTINUES FOR ALL WATERS THROUGH THE NEAR
TERM. A TIGHT SOUTHWESTERLY GRADIENT WILL KEEP WINDS IN THE 20 TO
25 KT RANGE MOST PLACES TODAY AND TONIGHT...WITH SEAS OF 4 TO 7
FT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...TIGHTENED GRADIENT FLOW WILL PERSIST
BETWEEN DEEP TROUGH REMAINING WEST OF AREA AND HIGH PRESSURE TO
THE EAST. THIS WILL MAINTAIN SOUTHERLY WINDS UP TO 15 TO 20 KTS
THROUGH MUCH OF THE PERIOD WHICH IN TURN WILL KEEP SEAS 4 TO 7 FT
HIGH. EXPECT SMALL CRAFT CONDITIONS TO CONTINUE THROUGH MUCH OF
THE PERIOD WITH WNA SHOWING A SLIGHT DROP IN WINDS AND SEAS SUN
AFTN FOLLOWED BY A SPIKE UP BY MONDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL ALSO BE QUITE WIDESPREAD THROUGH MUCH OF THE
PERIOD CREATING PERIODS OF HEAVY RAIN AND REDUCED VISBYS.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...GRADIENT WILL BEGIN TO RELAX MID TO LATE
WEEK AS HIGH PRESSURE TO THE EAST PUSHES WESTWARD AND LOW PRESSURE
TO THE WEST WEAKENS AND LIFTS NORTH. EXPECT SOUTHERLY WINDS
INITIALLY TO MAINTAIN 15 TO 20 KTS WITH A GRADUAL WEAKENING AND
BACKING OF WINDS TO THE S-SE THROUGH THE PERIOD. WNA SHOWS SEAS
DROPPING BELOW SCA THRESHOLDS TUES MORNING...MAINTAINING 3 TO 5 FT
THROUGH TUES NIGHT AND DROPPING TO 2 TO 4 FT THROUGH WEDNESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EDT SUNDAY FOR AMZ250-252-254-
256.
&&
$$
NEAR TERM...REK
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...REK/DL
MARINE...REK/RGZ
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1025 AM CDT SAT JUN 29 2013
.UPDATE...
THE FORECAST LOOKS TO BE ON TRACK THIS MORNING. THE ONLY MINOR
CHANGE MADE WAS TO PUSH BACK THE MENTION OF SHOWERS A COUPLE OF
HOURS LATER. OTHERWISE...REFRESHED THE GRIDS WITH CURRENT
CONDITIONS AND THE UPDATE HAS BEEN SENT OUT.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH MONDAY
CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A VORT MAX
MOVING SOUTH ACROSS SOUTHERN CANADA READY TO CROSS THE
INTERNATIONAL BORDER. THIS IS THE WAVE THAT WILL MOVE OVER THE
REGION TODAY AND BRING ISO/WDLY SCT SHOWERS AND THUNDERSHOWERS.
MODELS ALSO SHOWING A SUBTLE BACK DOOR COOL FRONT SLIDING
SOUTHWEST INTO THE NORTHEASTERN CWA WHICH WILL HELP TO AID IN
SHOWER DEVELOPMENT. MLCAPE VALUES ARE VERY LOW AND ONLY MAX OUT
AROUND 500 TO 600 J/KG ACROSS THE EASTERN CWA. MOST ALL HI RES
MODELS SHOWING DEVELOPMENT OF SMALL SHOWERS/THUNDERSHOWERS BY
AROUND 18Z AND PUSHES THEM AS FAR WEST AS THE JAMES VALLEY AND
EVEN A TAD FURTHER WEST. EXPECT THAT ANY ACTIVITY WILL DIMINISH
THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
THE REST OF THE SHORT TERM LOOKS RATHER QUITE WITH SURFACE HIGH
PRESSURE IN CONTROL OF THE WEATHER. WINDS WILL BE RATHER LIGHT
WITH PLEASANT TEMPERATURES. CONDITIONS LOOK TO BE DRY WITH PRECIP
CHANCES NOT INCREASING UNTIL LATER ON IN THE EXTENDED PERIOD.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT
THE LONGER RANGE MODEL SOLUTIONS ARE CERTAINLY LESS THAN
CONSISTENT WITH HANDLING UPPER LEVEL FLOW PATTERN EVOLUTION. THE
LATEST INSTALLMENT OF 00Z SOLUTIONS HAS THE MAMMOTH UPPER LEVEL
RIDGE OVER THE WEST FLATTENING OUT BY THURSDAY...WITH STRONGER
WESTERLIES AND EMBEDDED S/W`S MOVING SWIFTLY EASTWARD ACROSS THE
PACIFIC NORTHWEST OVER INTO THE NORTHERN PLAINS BY THE END OF NEXT
WEEK. DOUBTLESS...WHEN THE ALLBLEND POPS GET BOILED DOWN...THERE
WILL BE AT LEAST A COUPLE PERIODS IN THE EXTENDED WITH
PRECIPITATION CHANCES.
AT THIS POINT...TEMPERATURE TRENDS APPEAR TO BE COOLER EARLIER ON
IN THE PERIOD WITH A GRADUAL LOW LEVEL WAA/WARMING TREND HEADING
INTO THURSDAY/FRIDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
WINDS OUT OF THE NORTH/NORTHWEST WILL AGAIN PICK UP BY MID DAY. A
FEW SHOWERS COULD EFFECT KATY/KABR OFF AND ON THROUGHOUT THE DAY.
HOWEVER...THE PROBABILITY OF CONVECTION ACTUALLY LUMBERING ACROSS
TERMINAL AIRSPACE REMAINS LOW AND VFR CONDITIONS ARE EXPECTED TO BE
PREVALENT. WILL AMEND AS NEEDED FOR SHOWERS/STORMS THROUGHOUT THE
DAY AT ANY OF THE TERMINALS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...SERR
SHORT TERM...TMT
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH MONDAY
CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A VORT MAX
MOVING SOUTH ACROSS SOUTHERN CANADA READY TO CROSS THE
INTERNATIONAL BORDER. THIS IS THE WAVE THAT WILL MOVE OVER THE
REGION TODAY AND BRING ISO/WDLY SCT SHOWERS AND THUNDERSHOWERS.
MODELS ALSO SHOWING A SUBTLE BACK DOOR COOL FRONT SLIDING
SOUTHWEST INTO THE NORTHEASTERN CWA WHICH WILL HELP TO AID IN
SHOWER DEVELOPMENT. MLCAPE VALUES ARE VERY LOW AND ONLY MAX OUT
AROUND 500 TO 600 J/KG ACROSS THE EASTERN CWA. MOST ALL HI RES
MODELS SHOWING DEVELOPMENT OF SMALL SHOWERS/THUNDERSHOWERS BY
AROUND 18Z AND PUSHES THEM AS FAR WEST AS THE JAMES VALLEY AND
EVEN A TAD FURTHER WEST. EXPECT THAT ANY ACTIVITY WILL DIMINISH
THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
THE REST OF THE SHORT TERM LOOKS RATHER QUIET WITH SURFACE HIGH
PRESSURE IN CONTROL OF THE WEATHER. WINDS WILL BE RATHER LIGHT
WITH PLEASANT TEMPERATURES. CONDITIONS LOOK TO BE DRY WITH PRECIP
CHANCES NOT INCREASING UNTIL LATER ON IN THE EXTENDED PERIOD.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT
THE LONGER RANGE MODEL SOLUTIONS ARE CERTAINLY LESS THAN
CONSISTENT WITH HANDLING UPPER LEVEL FLOW PATTERN EVOLUTION. THE
LATEST INSTALLMENT OF 00Z SOLUTIONS HAS THE MAMMOTH UPPER LEVEL
RIDGE OVER THE WEST FLATTENING OUT BY THURSDAY...WITH STRONGER
WESTERLIES AND EMBEDDED S/W`S MOVING SWIFTLY EASTWARD ACROSS THE
PACIFIC NORTHWEST OVER INTO THE NORTHERN PLAINS BY THE END OF NEXT
WEEK. DOUBTLESS...WHEN THE ALLBLEND POPS GET BOILED DOWN...THERE
WILL BE AT LEAST A COUPLE PERIODS IN THE EXTENDED WITH
PRECIPITATION CHANCES.
AT THIS POINT...TEMPERATURE TRENDS APPEAR TO BE COOLER EARLIER ON
IN THE PERIOD WITH A GRADUAL LOW LEVEL WAA/WARMING TREND HEADING
INTO THURSDAY/FRIDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
WINDS OUT OF THE NORTH/NORTHWEST WILL AGAIN PICK UP BY MID DAY. A
FEW SHOWERS COULD EFFECT KATY/KABR OFF AND ON THROUGHOUT THE DAY.
HOWEVER...THE PROBABILITY OF CONVECTION ACTUALLY LUMBERING ACROSS
TERMINAL AIRSPACE REMAINS LOW AND VFR CONDITIONS ARE EXPECTED TO BE
PREVALENT. WILL AMEND AS NEEDED FOR SHOWERS/STORMS THROUGHOUT THE
DAY AT ANY OF THE TERMINALS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...DORN
SHORT TERM...TMT
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
245 PM MST SAT JUN 29 2013
.SYNOPSIS...EXPECT VERY HOT DAYTIME TEMPERATURES AGAIN SUNDAY.
GRADUALLY INCREASING MOISTURE WILL THEN LEAD TO THE DAILY CYCLE OF
MAINLY AFTERNOON AND EVENING THUNDERSTORMS DURING THE UPCOMING WEEK.
THE INCREASED MOISTURE WILL ALSO PROVIDE A MODERATION IN DAYTIME
TEMPERATURES DURING THE UPCOMING WEEK.
&&
.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED MOSTLY LESS THAN 35 DBZ
ECHOES ACROSS THE WHITE MOUNTAINS VALID 2140Z. THE REST OF SE AZ WAS
VOID OF PRECIP ECHOES AT THIS TIME. 29/18Z RUC HRRR SEEMED WELL
INITIALIZED REGARDING THE AREAL COVERAGE OF SHOWERS/TSTMS ACROSS
SWRN NM AND IS ACCEPTED FOR THE SHORT-TERM FORECAST. BULK OF
CONVECTIVE ACTIVITY TO MOVE SWWD ACROSS GREENLEE/GRAHAM COUNTIES
THRU EARLY THIS EVENING. ELSEWHERE...HAVE MAINTAINED A SLIGHT CHANCE
OF SHOWERS/TSTMS NEAR THE MOUNTAINS THIS EVENING. PRECIP-FREE
CONDITIONS TO THEN OCCUR AREA WIDE LATE TONIGHT.
29/12Z GFS/ECMWF WERE SIMILAR WITH DEPICTING A GRADUAL INCREASE OF
MOISTURE STARTING SUN AND CONTINUING DURING THE UPCOMING WEEK. THERE
WAS ESSENTIALLY NO MAJOR CHANGE TO THE INHERITED POP GRIDS FOR THIS
FORECAST PACKAGE. THUS...HAVE MAINTAINED A SLIGHT CHANCE OF
SHOWERS/TSTMS AS FAR WEST AS THE TUCSON METRO AREA SUN AFTERNOON AND
SUN EVENING. CHANCE-CATEGORY POPS TO OCCUR SUN AFTERNOON AND SUN
EVENING ACROSS THE MOUNTAINS OF GREENLEE/GRAHAM/COCHISE COUNTIES.
EXPECT A SIMILAR POP SCENARIO MON AFTERNOON AND MON EVENING.
THEREAFTER...POPS INCREASE INTO THE CHANCE-CATEGORY AS FAR WEST AS
TUCSON TUE AFTERNOON AND TUE EVENING...WITH A SLIGHT CHANCE OF
SHOWERS/TSTMS FURTHER WWD INTO THE TOHONO OODHAM NATION. THERE IS A
CHANCE OF SHOWERS/TSTMS WED AFTERNOON AND WED EVENING FROM TUCSON
EWD/SWD...AND LESSER CHANCES OF PRECIP ACROSS WRN/CENTRAL PIMA
COUNTY AND SOUTH-CENTRAL PINAL COUNTY.
THERE WERE SOME DIFFERENCES BETWEEN THE GFS/ECMWF THUR-SAT REGARDING
THE POSITION OF THE WRN STATES HIGH PRESSURE SYSTEM. THESE
DIFFERENCES ALSO YIELDED DIFFERENT MOISTURE VALUES AND MODEL QPF/S.
IN ESSENCE...ECMWF KEPT UPPER HIGH QUASI STATIONARY OVER THE GREAT
BASIN REGION...AND NO APPRECIABLE CHANGE IN MOISTURE ACROSS SE AZ.
MEANWHILE...GFS DEPICTED UPPER HIGH TO MOVE SWD INTO CENTRAL AZ.
THE CORRESPONDING PRECIP FIELDS WERE MARKEDLY DRIER BY NEXT SAT
VERSUS THE ECMWF. PER COORD WITH NEIGHBORING WFO/S...OPTED TO DEPICT
ONLY A SLIGHT DAILY REDUCTION IN POPS THUR-SAT. THUS...EXPECT AT
LEAST A SLIGHT CHANCE OF SHOWERS/TSTMS FROM TUCSON EWD/SWD TO OCCUR
THUR-SAT DURING THE AFTERNOON AND EVENING HOURS.
AS FOR TEMPS...HAVE MAINTAINED THE EXCESSIVE HEAT WARNING THRU 9 PM
MST SUN. HOWEVER...CONFIDENCE IS SOMEWHAT LOW THAT WIDESPREAD
WARNING CRITERIA WILL BE ACHIEVED SUN AFTERNOON. AT ANY RATE...THERE
SHOULD BE A GRADUAL MODERATION IN DAYTIME TEMPS MON-THUR IN RESPONSE
TO INCREASED MOISTURE ACROSS THE AREA.
&&
.AVIATION...ISOLD -TSRA MAINLY NEAR MTNS INTO EARLY EVENING...ENDING
BY 30/04Z AND AGAIN SUNDAY BETWEEN 30/21Z AND 01/04Z. OTHERWISE...
SCT-BKN CLOUDS MOSTLY AT OR ABOVE 12K FT AGL THRU SUNDAY AFTERNOON
OR 01/00Z. NORMAL DIURNAL SURFACE WINDS WITH AFTERNOON SPEEDS OF
10-15 KTS AND GUSTS TO 20 KTS...EXCEPT STRONGER GUSTS POSSIBLE NEAR
-TSRA. VERY HOT SURFACE TEMPERATURES WILL PRODUCE INCREASED TAKE OFF
LENGTHS DURING PEAK HEATING THIS WEEKEND. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...ISOLATED AFTERNOON AND EVENING THUNDERSTORMS MAINLY
ACROSS THE HIGHER TERRAIN ARE EXPECTED AGAIN SUNDAY. GRADUALLY
INCREASING MOISTURE WILL PRODUCE A DAILY CYCLE OF MAINLY AFTERNOON
AND EVENING THUNDERSTORMS DURING THE UPCOMING WORK WEEK. AT THE
SAME TIME...VERY HOT TEMPERATURES WILL MODERATE SOMEWHAT AS MOISTURE
INCREASES. GUSTY WINDS WILL PREVAIL DURING THE AFTERNOON HOURS DUE
TO STRONG DAYTIME HEATING...AND WITH STRONG AND ERRATIC OUTFLOW
WINDS NEAR THUNDERSTORMS.
&&
.CLIMATE...THE MINIMUM TEMPERATURE SO FAR AT TUCSON INTERNATIONAL
AIRPORT IS 84 DEGREES. THIS TEMPERATURES TIES THE RECORD HIGHEST
MINIMUM TEMPERATURE FOR TODAY (JUN 29) WHICH WAS SET IN 1898.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING UNTIL 9 PM MST SUNDAY FOR AZZ501>506-509-
515.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
BF/KD
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
151 PM EDT SAT JUN 29 2013
.SYNOPSIS...
A DEEPENING UPPER LEVEL TROUGH OVER THE EASTERN US WILL PERSIST
OVER THE EASTERN US THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL
COMBINED WITH ABUNDANT MOISTURE TO CONTINUE THE CHANCES OF MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER LEVEL TROUGH OVER THE EASTERN CONUS WILL CONTINUE TO DEEPEN.
CANNOT RULE OUT A WEAK DISTURBANCE OR TWO CROSSING THE AREA IN
SOUTHWEST FLOW ALOFT. CONVECTION ALREADY DEVELOPING ALONG A PRE-
FRONTAL TROUGH OVER THE UPSTATE AND DIFFERENTIAL HEATING BOUNDARIES
IN THE CSRA AND EASTERN MIDLANDS. CHANCES OF CONVECTION STILL
APPEAR HIGHEST OVER THE FAR EASTERN MIDLANDS WHERE PWAT REMAINS
NEAR 2.00 INCHES. LOCAL HIGH RESOLUTION MODEL INDICATE CONVECTION
OVER THE EASTERN MIDLANDS TO THE COAST THIS AFTERNOON AND EVENING...
BUT ALSO DEVELOPS AFTERNOON CONVECTION IN THE PIEDMONT. WILL KEEP
POPS FROM 30 PERCENT WEST TO 60 PERCENT EAST THIS AFTERNOON INTO
THE EVENING. TEMPERATURES THIS AFTERNOON STILL EXPECTED TO PEAK IN
THE UPPER 80S TO LOWER 90S.
AT LEAST SCATTERED CONVECTION SHOULD CONTINUE OVERNIGHT AS THE
UPPER TROUGH DEEPENS... ALLOWING A WEAK SHORT WAVE TO MOVE ACROSS
THE AREA. LOWS WILL CONTINUE IN THE LOWER 70S.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
UPPER LEVEL TROUGH WILL CONTINUE TO DEEPEN OVER THE EASTERN US
WITH A WEAK SURFACE LOW OVER THE TN VALLEY. WITH SOUTHERLY WINDS
OVER THE AREA...A CONVERGENCE AREA WILL DEVELOP ACROSS THE AREA
RESULTING IN A VERY MOIST AIR MASS AND INCREASING CHANCES OF
SHOWERS AND THUNDERSTORMS. WITH HEATING ON SUNDAY PUSHING
TEMPERATURES INTO THE UPPER 80S EXPECT SHOWERS AND THUNDERSTORMS
TO DEVELOP ACROSS THE FORECAST AREA. THIS WILL KEEP LIKELY CHANCES
OF SHOWERS AND THUNDERSTORMS OVER THE AREA FROM EARLY SUNDAY INTO
SUNDAY NIGHT. WITH PWAT VALUES AROUND 2 INCHES THE POTENTIAL FOR
HEAVY RAIN WILL BE A CONCERN WHICH WILL NEED TO BE MONITORED.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH AN ACTIVE
PATTERN PERSISTING OVER THE EASTERN US. UPPER LEVEL PATTERN WILL
REMAIN HIGHLY AMPLIFIED WITH A RIDGE OVER THE WESTERN U.S. AND A
CUT OFF LOW OVER THE EASTERN U.S. THIS WILL RESULT IN VERY SLOW
PROGRESSION OF THE PATTERN WITH MOIST SOUTHERLY FLOW OVER THE AREA
THROUGH THE LONG TERM. CHANCES OF SHOWERS AND THUNDERSTORMS WILL
CONTINUE MONDAY THROUGH FRIDAY. WITH CLOUDS AND SHOWERS DAYTIME
HIGHS WILL BE SLIGHTLY BELOW NORMAL WITH UPPER 80S TO AROUND 90
WITH OVERNIGHT LOWS NEAR NORMAL IN THE LOWER 70S.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
AFTERNOON CONVECTION GETTING STARTED IN MOIST AND UNSTABLE
AIRMASS. BEST LOCATION FOR CONVECTION APPEARS TO BE ACROSS THE
EASTERN MIDLANDS...INCLUDING OGB...WHERE MOISTURE AND INSTABILITY
ARE HIGHER. CONVECTION ALSO GETTING STARTED IN THE UPSTATE ALONG A
SURFACE TROUGH. CANNOT RULE OUT CONVECTION AT ANY TAF SITE. GIVEN
LOW CONFIDENCE FOR TIMING AND LOCATION...WILL NOT INCLUDE
CONVECTION OTHER TAFS AT THIS TIME. THE RUC AND NAM MODELS...AS
WELL AS THE GFS TO A LESSER DEGREE...ARE INDICATING MVFR OR LOWER
CIGS AFTER 30/06Z. CONFIDENCE IS MODERATE...SO WILL INCLUDE LATE
NIGHT MVFR CIGS. MODERATE TO HIGH CONFIDENCE FOR WIDESPREAD
CONVECTION ACROSS THE TAF SITES AFTER 30/12Z GIVEN ABUNDANT
MOISTURE AND INCREASING LIFT.
EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS POSSIBLE EACH DAY
IN MAINLY AFTERNOON/EVENING THUNDERSTORMS...AS WELL AS LATE
NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CLIMATE...
THROUGH FRI JUNE 28TH...AUGUSTA GA BUSH FIELD HAS RECEIVED A TOTAL
OF 10.52 INCHES OF RAIN SO FAR FOR THE MONTH OF JUNE. THIS HAS
ALREADY ESTABLISHED JUNE 2013 AS THE 2ND WETTEST JUNE ON RECORD AT
AUGUSTA. THE WETTEST JUNE ON RECORD AT AUGUSTA IS 10.59 INCHES SET
IN 2004...SO TO ESTABLISH JUNE 2013 AS THE WETTEST JUNE ON RECORD
AT AUGUSTA...AGS NEEDS TO RECEIVE 0.08 MORE INCHES OF RAIN THIS
MONTH. ALTHOUGH WE DO NOT KEEP RECORDS FOR DANIEL FIELD...IT HAS
RECEIVED 13.47 INCHES OF RAIN SO FAR FOR JUNE. QUITE A DRAMATIC
DIFFERENCE FROM LAST JUNE AS AUGUSTA BUSH FIELD ONLY RECEIVED 2.48
INCHES FOR THE MONTH.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
145 PM EDT SAT JUN 29 2013
.PREV DISCUSSION... /ISSUED 1005 AM EDT SAT JUN 29 2013/
UPDATE...
13Z SURFACE ANALYSIS HAS A TROUGH/WEAK FRONT ACROSS NORTHERN GA.
THE MAIN COLD FRONT/WIND SHIFT/DEWPOINT GRADIENT IS STILL BACK
OVER THE MID MISSISSIPPI RIVER VALLEY. SOME CLEARING IS NOTED
ACROSS NORTHERN GA BEHIND THE TROUGH...BUT DO EXPECT DIURNAL CU TO
FILL BACK IN DURING THE HEATING OF THE DAY. STILL COPIOUS CLOUD
COVER ACROSS THE CENTRAL AND SOUTHERN CWFA. BREAKS ARE ALREADY
STARTING TO OCCUR AND SKIES SHOULDN`T BE BKN MUCH LONGER.
WITH THE WIND SHIFT/LOWER DEWPOINTS BACK OVER THE MID MISSISSIPPI
RIVER VALLEY...THERE SHOULDN`T BE MUCH OF A DROP IN DEWPOINTS
UNTIL LATER IN THE AFTERNOON. 10Z RUNS OF THE HRRR BREAK OUT SOME
SHOWERS RIGHT AROUND THE METRO AREA IN THE 16-18Z TIME FRAME.
THINK ISOLD SHOULD BE ABOUT THE EXTENT OF COVERAGE AND THUNDER
WILL BE A STRUGGLE ACROSS THE CENTRAL CWFA. LIKE THE SCT COVERAGE
FURTHER SOUTH. NO CHANGE TO POPS AT THIS TIME.
PREV DISCUSSION... /ISSUED 749 AM EDT SAT JUN 29 2013/
UPDATE...
NEAR TERM.
FCST NOT TOO FAR OFF TRACK. JUST WHEN SHRA/TSRA APPEAR TO HAVE
DISSIPATED OVER SRN COUNTIES...ANOTHER ONE DEVELOPS. MODELS STILL
WANT TO ADVECT/MIX DOWN DRIER AIR OVER NORTH AND MUCH OF CENTRAL
GA TODAY. MAY TAKE SOME TIME...BUT APPEARS DRIER AIR WILL LIMIT
INSTABILITY...ESP OVER NORTH GA TODAY. MAY UPDATE POPS/WX ONE LAST
TIME. REST OF FCST LOOKS GOOD.
SNELSON
PREV DISCUSSION... /ISSUED 428 AM EDT SAT JUN 29 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...
PRIMARY CONCERN IN THE SHORT TERM PERIOD IS COVERAGE AND EXTENT OF
SCT TSRA THIS AFTERNOON. INTERESTING UPPER AIR PATTERN. 3 WAVE
NORTHERN HEMISPHERIC PATTERN IN NORTHERN LATITUDES FAVORS
RETROGRADING PROPAGATION WHILE A COUPLE CUTOFF LOWS IN MID AND LOWER
LATITUDES OVER ERN PACIFIC AND CENTRAL ATLANTIC. BROAD UPPER TROUGH
CENTERED OVER THE ERN CONUS PROGGED TO BECOME MORE AMPLIFIED AND
SHORTER WAVELENGTH WHILE SLOWLY RETROGRADING WEST.
ON THE MESOSCALE...DRIER AIR AT SFC HAS PUSHED INTO NE GA THIS
MORNING BUT NOT EXPECTED TO MOVE MUCH FURTHER SOUTH. SHALLOW RICH
MOISTURE COULD MIX OUT THIS AFTERNOON OVER ALL OF NORTH GA...
PROVIDING SMALL RELIEF TO RECENT HUMID CONDITIONS. HOWEVER...MIDDLE
GA WILL REMAIN MOIST WITH CORRESPONDINGLY HIGHER INSTABILITY. NO
WELL DEFINED SFC FRONT BUT WILL BE A MOISTURE AND CLOUD BOUNDARY AND
DIFFERENTIAL DIABATIC HEATING MAY PROVIDE FOCUS FOR STORMS OVER
MIDDLE GA. HIRES MODEL REFLECTIVITY AND NAM/GFS/SREF/ECMWF ALSO
FAVOR THIS AREA FOR CONVECTION. CONVECTION COULD CONTINUE INTO THE
LATE EVENING AND OVERNIGHT THEN FIRE UP AGAIN SUNDAY AFTERNOON AS
UPPER TROF AMPLIFIES AND EVENTUALLY CLOSED LOW DEVELOPS OVER THE MS
VALLEY STATES.
VERY UNUSUAL...AMPLIFIED BLOCKING PATTERN FOR NEAR THE FIRST OF
JULY. WILL HAVE TO WATCH THIS EARLY NEXT WEEK FOR INCREASING AND
ABNORMALLY HIGH MOISTURE CONTENT WITH HEAVY RAIN POTENTIAL.
SNELSON
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THINGS ARE STILL STATUS QUO FOR THE EXTENDED FORECAST. LARGE
UPPER LEVEL TROUGH HAS BEGUN DIGGING INTO THE SOUTHEASTERN STATES
AND WILL CONTINUE THROUGH THE BEGINNING OF NEXT WEEK. THIS TROUGH
DEEPENS OVER THE GREAT LAKE STATES AND PUSHES SOUTH THROUGH
MONDAY/TUESDAY. THIS TROUGH WILL KEEP NORTH AND CENTRAL GA IN
MOIST WEST TO SOUTHWESTERLY FLOW THROUGH DAY 7. THIS WILL KEEP
DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS IN THE FORECAST EVERY
DAY. THERE IS A WEAK COLD FRONT THAT STALLS ACROSS CENTRAL GA
THROUGH THE EXTENDED AND ACTS AS A CATALYST FOR SHOWERS AND
THUNDERSTORMS. WITH VERY LITTLE UPPER LEVEL MOVEMENT...THIS
BOUNDARY IS NOT EXPECTED TO MOVE VERY MUCH AND IT WILL CONTINUE TO
AFFECT CONVECTIVE DEVELOPMENT THROUGH DAY 7.
01
&&
.AVIATION...
18Z UPDATE...
SFC ANALYSIS SHOWS A TROUGH ACROSS NORTHERN GA...WTIH A COLD FRONT
MOVING INTO CENTRAL AL. SHOWERS HAVE STARTED TO DEVELOP FROM AHN
SW. SHOWERS SHOULD MOSTLY REMAIN SOUTH OF ATL THROUGH THE
AFTERNOON. DIURNAL CU EXPECTED FOR THE AFT. INCREASING CLOUDINESS
EXPECTED OVERNIGHT...BUT CIGS REMAIN AOA 3500 FT. COVERAGE OF
STORMS SHOULD BE HIGHER TOMORROW AS AN UPPER TROUGH FUNNELS
MOISTURE NORTHWARD ACROSS GA.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE SHRA/TSRA THIS AFT AND OVERNIGHT CIGS. HIGH
CONFIDENCE REMAINING ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 69 86 68 / 20 30 50 50
ATLANTA 87 70 85 69 / 20 20 40 40
BLAIRSVILLE 83 62 80 63 / 20 20 40 50
CARTERSVILLE 87 66 85 65 / 20 20 30 40
COLUMBUS 90 72 88 68 / 30 30 40 30
GAINESVILLE 86 69 83 68 / 20 20 40 50
MACON 89 71 87 69 / 30 30 60 40
ROME 88 66 86 65 / 10 20 30 30
PEACHTREE CITY 88 67 85 66 / 20 20 30 30
VIDALIA 88 72 87 73 / 50 50 70 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
208 PM EDT SAT JUN 29 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EDT SAT JUN 29 2013
RAIN SHOWERS ARE EXPECTED FROM TIME TO TIME ACROSS CENTRAL INDIANA
THROUGH THE MIDDLE OF NEXT WEEK AS AN UPPER LOW DEVELOPS ACROSS THE
OHIO VALLEY WITHIN A BROAD UPPER TROUGH. A FEW THUNDERSTORMS STORMS
ARE ALSO POSSIBLE. LOOK FOR COOL TEMPERATURES AS AFTERNOON HIGH
TEMPERATURES WILL ONLY BE IN THE 70S THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 950 AM EDT SAT JUN 29 2013
CLOUDS CONTINUE TO DEVELOP AND SPREAD SOUTH ACROSS THE AREA
TODAY...BUT ENOUGH SUN MAY PERSIST ACROSS THE SOUTH TO ALLOW
TEMPERATURES THERE TO GET A LITTLE WARMER THAN PREVIOUSLY THOUGHT.
BUMPED UP TEMPERATURES A BIT IN THE SOUTH.
RAIN IS DEVELOPING ACROSS THE AREA...WITH MORE RAIN UPSTREAM IN
ILLINOIS. HRRR MODEL SHOWING ADDITIONAL RAIN QUICKLY DEVELOPING THIS
AFTERNOON. THUS CONTINUED HIGH POPS DURING THE AFTERNOON
HOURS...JUST CHANGED THE WORDING TO PERIODS OF RAIN TO INDICATE DRY
PERIODS.
PREVIOUS DISCUSSION FOLLOWS...
SURFACE ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER WESTERN
NEW YORK AND BROAD CYCLONIC FLOW ACROSS INDIANA. A TROUGH AXIS
EXTENDED ACROSS SOUTHERN MICHIGAN AND NORTHERN INDIANA TO CENTRAL
ILLINOIS. DEW POINTS WERE STILL RELATIVELY HUMID...IN THE LOWER AND
MIDDLE 60S. WATER VAPOR IMAGERY SHOWS...STRONG RIDGING WAS IN PLACE
ACROSS THE WESTERN UNITED STATES WHILE A DEEP LOW WAS FOUND ACROSS
THE GREAT LAKES AND NORTHEAST. NORTHWEST FLOW WAS SPILLING INTO THE
PLAINS STATES AND OHIO VALLEY BETWEEN THESE TWO SYSTEMS.
FORECAST SOUNDINGS AND TIME HEIGHT BOTH INDICATE PLENTY OF LOWER
LEVEL MOISTURE AVAILABLE TODAY AS THE PREVIOUSLY MENTIONED TROUGH
AXIS PUSHES ACROSS THE FORECAST AREA. TIME HEIGHT SECTIONS
INDICATE BEST LIFT AVAILABLE AROUND 18Z AND FORECAST SOUNDINGS
SHOW DEEP SATURATION NEAR THAT TIME. HOWEVER THUS WILL TREND POPS
HIGHER THAN MAVMOS OR METMOS. AGAIN...A COMPLETE WASHOUT IS NOT
EXPECTED TODAY...HOWEVER MANY AREAS SHOULD SEE PRECIP AS THIS
CYCLONIC FLOW...TROUGH AXIS AND CONVECTIVE TEMPERATURES IN THE
UPPER 60S ALL PROVIDE FAVORABLE CONDITIONS FOR PRECIP.
GIVEN THE EXPECTED CLOUDS AND PRECIPITATION WILL TREND HIGHS AT OR
BELOW MAVMOS VALUES.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 224 AM EDT SAT JUN 29 2013
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND. MAIN CHALLENGE WILL AGAIN BE POPS.
BOTH THE GFS AND THE NAM CONTINUE TO SUGGEST THAT THE BROAD UPPER
LOW WILL REMAIN OVER THE OHIO VALLEY AND INDIANA THROUGH AT LEAST
TUESDAY NIGHT. TIME HEIGHT SECTIONS CONTINUES TO SHOW PLENTIFUL
MOISTURE IN THE LOWER LEVELS. FORECAST SOUNDINGS SHOW CONVECTIVE
TEMPERATURES EACH DAY IN THE UPPER 60S TO AROUND 70...WHICH IS
QUITE REACHABLE. CAPE APPEARS QUITE LIMITED DURING THIS
TIME...WITH VALUES OF LESS THAN 1000 J/KG. THUS WIDESPREAD THUNDER
IS NOT EXPECTED...AN ISOLATED AFTERNOON TSRA CANNOT BE RULED OUT.
NOT CONFIDENT IN TIMING ANY SPECIFIC TROUGH AXIS PASSING AROUND
THE UPPER LOW FLOW TO FOCUS POP AND PRECIP...HOWEVER WILL RAISE
POPS DURING THE AFTERNOONS AS FORCING FROM ANY DAYTIME HEATING
SHOULD AID DEVELOPMENT. WILL STICK CLOSE TO MAVMOS POPS DURING
THE OVERNIGHT PERIODS. AGAIN...A WASHOUT IS NOT EXPECTED THROUGH
THIS PERIOD...BUT RATHER LIGHT...PASSING SHOWERS FROM TIME TO
TIME.
AGAIN...WITH LITTLE CHANGE IN TEMPS AND THE EXPECTED CLOUDS AND
RAIN WILL TREND DAILY HIGHS AT OR BELOW MAVMOS AND TREND DAILY
LOWS WARMER.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 208 PM EDT SAT JUN 29 2013
MODELS ARE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE USED
FOR MOST ITEMS.
UPPER AND SURFACE LOWS WILL RETROGRADE ACROSS THE AREA THROUGH THE
EARLY PART OF THE EXTENDED. KEPT CHANCES FOR RAIN THROUGH
INDEPENDENCE DAY WITH THE SYSTEM STILL IN THE VICINITY...ALTHOUGH
CHANCES CONTINUE TO LOOK PRETTY LOW BY INDEPENDENCE DAY AS THE
SYSTEM MOVES WEST.
MODELS ARE TRYING TO BRING PRECIPITATION INTO THE AREA AGAIN ON
FRIDAY BUT AM NOT READY TO QUITE BUY INTO THIS SCENARIO YET WITH
HIGH PRESSURE TRYING TO BUILD IN. WENT AGAINST ALLBLEND HERE AND
WENT DRY. BY SATURDAY MODELS AGREE BETTER ON RAIN CHANCES RETURNING
SO WENT LOW POPS.
TEMPERATURES WILL GRADUALLY WARM THROUGH THE PERIOD AS THE UPPER LOW
LOSES ITS INFLUENCE.
&&
.AVIATION /DISCUSSION FOR THE 291800Z TAFS/...
ISSUED AT 1248 PM EDT SAT JUN 29 2013
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS WILL PROVIDE A MIX OF
MVFR AND VFR CONDITIONS ACROSS THE SITES...LEADING TO PREDOMINANT
MVFR OVERNIGHT INTO SUNDAY.
AS AN UPPER LOW MOVES DOWN INTO THE AREA AND DAYTIME HEATING
OCCURS...SHOWERS WILL CONTINUE TO INCREASE IN COVERAGE THIS
AFTERNOON. THUS WENT PREDOMINANT SHOWERS. THERE ARE SOME STORMS
AROUND...BUT COVERAGE IS SUCH THAT A HIT AT A TERMINAL IS NOT
GUARANTEED...SO ONLY WENT VCTS. EXPECT MVFR CEILINGS/VISIBILITIES IN
SHOWERS. IF A HEAVIER SHOWER OR STORM MOVES THROUGH...BRIEF IFR IS
POSSIBLE.
EXPECT SOME DECREASE IN SHOWER COVERAGE THIS EVENING WITH LOSS OF
HEATING...BUT STILL ENOUGH TO KEEP AT LEAST VCSH MENTION. SIMILAR
CONDITIONS WILL CONTINUE INTO SUNDAY MORNING WITH SCATTERED SHOWERS
AROUND. CEILINGS LOOK TO DIP INTO AND THEN STAY IN MVFR CATEGORY
OVERNIGHT INTO SUNDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/50
SHORT TERM...PUMA
LONG TERM....50
AVIATION...50
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FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1248 PM EDT SAT JUN 29 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EDT SAT JUN 29 2013
RAIN SHOWERS ARE EXPECTED FROM TIME TO TIME ACROSS CENTRAL INDIANA
THROUGH THE MIDDLE OF NEXT WEEK AS AN UPPER LOW DEVELOPS ACROSS THE
OHIO VALLEY WITHIN A BROAD UPPER TROUGH. A FEW THUNDERSTORMS STORMS
ARE ALSO POSSIBLE. LOOK FOR COOL TEMPERATURES AS AFTERNOON HIGH
TEMPERATURES WILL ONLY BE IN THE 70S THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 950 AM EDT SAT JUN 29 2013
CLOUDS CONTINUE TO DEVELOP AND SPREAD SOUTH ACROSS THE AREA
TODAY...BUT ENOUGH SUN MAY PERSIST ACROSS THE SOUTH TO ALLOW
TEMPERATURES THERE TO GET A LITTLE WARMER THAN PREVIOUSLY THOUGHT.
BUMPED UP TEMPERATURES A BIT IN THE SOUTH.
RAIN IS DEVELOPING ACROSS THE AREA...WITH MORE RAIN UPSTREAM IN
ILLINOIS. HRRR MODEL SHOWING ADDITIONAL RAIN QUICKLY DEVELOPING THIS
AFTERNOON. THUS CONTINUED HIGH POPS DURING THE AFTERNOON
HOURS...JUST CHANGED THE WORDING TO PERIODS OF RAIN TO INDICATE DRY
PERIODS.
PREVIOUS DISCUSSION FOLLOWS...
SURFACE ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER WESTERN
NEW YORK AND BROAD CYCLONIC FLOW ACROSS INDIANA. A TROUGH AXIS
EXTENDED ACROSS SOUTHERN MICHIGAN AND NORTHERN INDIANA TO CENTRAL
ILLINOIS. DEW POINTS WERE STILL RELATIVELY HUMID...IN THE LOWER AND
MIDDLE 60S. WATER VAPOR IMAGERY SHOWS...STRONG RIDGING WAS IN PLACE
ACROSS THE WESTERN UNITED STATES WHILE A DEEP LOW WAS FOUND ACROSS
THE GREAT LAKES AND NORTHEAST. NORTHWEST FLOW WAS SPILLING INTO THE
PLAINS STATES AND OHIO VALLEY BETWEEN THESE TWO SYSTEMS.
FORECAST SOUNDINGS AND TIME HEIGHT BOTH INDICATE PLENTY OF LOWER
LEVEL MOISTURE AVAILABLE TODAY AS THE PREVIOUSLY MENTIONED TROUGH
AXIS PUSHES ACROSS THE FORECAST AREA. TIME HEIGHT SECTIONS
INDICATE BEST LIFT AVAILABLE AROUND 18Z AND FORECAST SOUNDINGS
SHOW DEEP SATURATION NEAR THAT TIME. HOWEVER THUS WILL TREND POPS
HIGHER THAN MAVMOS OR METMOS. AGAIN...A COMPLETE WASHOUT IS NOT
EXPECTED TODAY...HOWEVER MANY AREAS SHOULD SEE PRECIP AS THIS
CYCLONIC FLOW...TROUGH AXIS AND CONVECTIVE TEMPERATURES IN THE
UPPER 60S ALL PROVIDE FAVORABLE CONDITIONS FOR PRECIP.
GIVEN THE EXPECTED CLOUDS AND PRECIPITATION WILL TREND HIGHS AT OR
BELOW MAVMOS VALUES.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 224 AM EDT SAT JUN 29 2013
MODELS ARE IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND WILL
USE A BLEND. MAIN CHALLENGE WILL AGAIN BE POPS.
BOTH THE GFS AND THE NAM CONTINUE TO SUGGEST THAT THE BROAD UPPER
LOW WILL REMAIN OVER THE OHIO VALLEY AND INDIANA THROUGH AT LEAST
TUESDAY NIGHT. TIME HEIGHT SECTIONS CONTINUES TO SHOW PLENTIFUL
MOISTURE IN THE LOWER LEVELS. FORECAST SOUNDINGS SHOW CONVECTIVE
TEMPERATURES EACH DAY IN THE UPPER 60S TO AROUND 70...WHICH IS
QUITE REACHABLE. CAPE APPEARS QUITE LIMITED DURING THIS
TIME...WITH VALUES OF LESS THAN 1000 J/KG. THUS WIDESPREAD THUNDER
IS NOT EXPECTED...AN ISOLATED AFTERNOON TSRA CANNOT BE RULED OUT.
NOT CONFIDENT IN TIMING ANY SPECIFIC TROUGH AXIS PASSING AROUND
THE UPPER LOW FLOW TO FOCUS POP AND PRECIP...HOWEVER WILL RAISE
POPS DURING THE AFTERNOONS AS FORCING FROM ANY DAYTIME HEATING
SHOULD AID DEVELOPMENT. WILL STICK CLOSE TO MAVMOS POPS DURING
THE OVERNIGHT PERIODS. AGAIN...A WASHOUT IS NOT EXPECTED THROUGH
THIS PERIOD...BUT RATHER LIGHT...PASSING SHOWERS FROM TIME TO
TIME.
AGAIN...WITH LITTLE CHANGE IN TEMPS AND THE EXPECTED CLOUDS AND
RAIN WILL TREND DAILY HIGHS AT OR BELOW MAVMOS AND TREND DAILY
LOWS WARMER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 224 AM EDT SAT JUN 29 2013
ENSEMBLES INDICATE AN UPPER LOW WILL BE LOCATED OVER THE MIDWEST AT
THE BEGINNING OF THE PERIOD. THIS UPPER LOW IS EXPECTED TO GRADUALLY
WEAKEN AND RETROGRADE A BIT TO THE NORTHWEST AS THE WESTERN ATLANTIC
SUB TROPICAL RIDGE BEGINS TO BUILD BACK INTO THE SOUTHEAST PARTS OF
THE COUNTRY TOWARDS THE MIDDLE AND END OF NEXT WEEK.
WILL CONTINUE WITH CHANCE POPS ON TUESDAY AND WEDNESDAY WITH THE
UPPER LOW NEARBY. BY THURSDAY AND FRIDAY...HEIGHTS ARE EXPECTED TO
RISE...SO THINK PRECIPITATION THREAT WILL DIMINISH BY THURSDAY AND
FRIDAY. WILL LEAVE SOME SMALL CHANCE POPS ON THURSDAY FOR NOW...BUT
IT IS POSSIBLE THEY CAN BE DROPPED AT SOME POINT IN THE FUTURE IF
TRENDS CONTINUE IN THIS DIRECTION.
&&
.AVIATION /DISCUSSION FOR THE 291800Z TAFS/...
ISSUED AT 1248 PM EDT SAT JUN 29 2013
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS WILL PROVIDE A MIX OF
MVFR AND VFR CONDITIONS ACROSS THE SITES...LEADING TO PREDOMINANT
MVFR OVERNIGHT INTO SUNDAY.
AS AN UPPER LOW MOVES DOWN INTO THE AREA AND DAYTIME HEATING
OCCURS...SHOWERS WILL CONTINUE TO INCREASE IN COVERAGE THIS
AFTERNOON. THUS WENT PREDOMINANT SHOWERS. THERE ARE SOME STORMS
AROUND...BUT COVERAGE IS SUCH THAT A HIT AT A TERMINAL IS NOT
GUARANTEED...SO ONLY WENT VCTS. EXPECT MVFR CEILINGS/VISIBILITIES IN
SHOWERS. IF A HEAVIER SHOWER OR STORM MOVES THROUGH...BRIEF IFR IS
POSSIBLE.
EXPECT SOME DECREASE IN SHOWER COVERAGE THIS EVENING WITH LOSS OF
HEATING...BUT STILL ENOUGH TO KEEP AT LEAST VCSH MENTION. SIMILAR
CONDITIONS WILL CONTINUE INTO SUNDAY MORNING WITH SCATTERED SHOWERS
AROUND. CEILINGS LOOK TO DIP INTO AND THEN STAY IN MVFR CATEGORY
OVERNIGHT INTO SUNDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/50
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...50
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FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS JACKSON KY
139 PM EDT SAT JUN 29 2013
.UPDATE...
ISSUED AT 916 AM EDT SAT JUN 29 2013
LATEST HRRR RUN IS SHOWING SCT PRECIPITATION DEVELOPING BY 16Z AND
INCREASING IN COVERAGE THROUGHOUT THE AFTERNOON. WILL CONTINUE WITH
PREVIOUS FORECAST THINKING THAT HIGHEST POTENTIAL FOR CONVECTION WILL
BE IN THE NORTHERN CWA...BUT WENT AHEAD AND BUMPED UP POPS SOONER IN
THE DAY TO COVER ANY SHOWERS OR POSSIBLE THUNDERSTORMS THAT DEVELOP
LATE THIS MORNING. CURRENT SATELLITE IS ALREADY SHOWING SOME SCT CU
DEVELOPING AND MOVING SE...SO EXPECT DEVELOPMENT TO ONLY INCREASE AS
WE GET LATER IN THE MORNING. OTHER FORECAST PARAMETERS SEEM TO BE ON
TRACK SO ONLY MINOR TWEEKS WERE MADE FOR TODAY.
UPDATE ISSUED AT 742 AM EDT SAT JUN 29 2013
UPDATED THE FORECAST TO DELAY THE ONSET OF PRECIPITATION BY A FEW
HOURS BASED ON CURRENT CONDITIONS AND LATEST MODEL TRENDS. THE REST OF
THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 336 AM EDT SAT JUN 29 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM PERIOD. A
UNCHARACTERISTIC UPPER LOW AND TROUGH ARE GOING TO START DROPPING
INTO THE AREA FROM THE NORTH. AT THE SAME TIME THIS TROUGH IS
DROPPING DOWN...A SHORT WAVE WILL BE MOVING AROUND THE TROUGH. THIS
SHOULD PROVIDE AN EXTRA BOOST NEEDED TO KICK OFF SHOWERS AND
THUNDERSTORMS TODAY. THE ONE THING THAT IS HELPING TO RETARD
DEVELOPMENT TODAY IS SOME WARM AIR IN THE MID LAYERS BETWEEN 500
-600 HPA. THIS WILL HELP TO CAP THE STORMS SOMEWHAT AND IS WHAT IS
LIMITING THE COVERAGE TO SCATTERED VERSUS NUMEROUS. WITH THE WEAK
SHEAR AND CAPPING IN THE MID LAYERS...THIS WILL MAKE IT TOUGH TO GET
A THUNDERSTORM TODAY...MUCH LESS A SEVERE ONE. AFTER MIDNIGHT...MOST
CONVECTION SHOULD BE OVER WITH ONLY A STRAY STORM OR TWO POSSIBLE.
ON SUNDAY...THE CAPPING IS NOT AS PRONOUNCED...SO THE CHANCES OF
THUNDERSTORMS WILL BE GREATER...HOWEVER...THEY SHOULD STILL BE ONLY
THE GARDEN VARIETY. TEMPERATURES WILL CONTINUE TO BE BIT LOWER THAN
NORMAL OVER THE NEXT FEW DAYS DUE TO THE UPPER TROUGH DROPPING
SOUTH. WENT ABOUT ONE DEGREE COOLER THAN THE MODEL BLEND.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 336 AM EDT SAT JUN 29 2013
AN UPPER LEVEL LOW WILL SPIN JUST TO OUR WEST EARLY IN THE
PERIOD...BEFORE LIFTING TO THE NORTH AS A LARGE RIDGE OF HIGH
PRESSURE BACKS TO THE EAST COAST TO END THE PERIOD. THIS PATTERN
WILL CAUSE A DEEP SOUTHERLY FLOW TO BECOME ENTRENCHED OVER OUR
REGION SUPPLYING PLENTY OF MOISTURE FOR DAILY SHOWERS AND
THUNDERSTORMS. THE CONVECTION WILL LIKELY BE DIURNALLY BASED WITH
WEAK TRIGGERS SO WILL ADVERTISE POPS AND SKY COVER PEAKING DURING
THE MID TO LATE AFTERNOON HOURS EACH DAY. WILL DECREASE RAIN CHANCES
A LITTLE BIT TOWARD THE END OF THE PERIOD AS THE UPPER LOW MOVES
AWAY FROM THE AREA...ALTHOUGH MOISTURE WILL REMAIN PLENTIFUL.
TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY BELOW SEASONAL NORMS...
INCHING UP A TAD LATE IN THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 138 PM EDT SAT JUN 29 2013
SCT SHOWERS HAVE DEVELOPED ACROSS THE NORTHERN HALF OF THE
CWA...AND WILL PERSIST THROUGH THE EVENING. EXPECT THE MAJORITY OF
THESE SHOWERS AND POTENTIAL THUNDERSTORMS TO REMAIN ACROSS THE
NORTHERN HALF OF THE STATE...MAINLY IMPACTING AS FAR SOUTH AS KJKL.
HOWEVER...A SHOWER AND ISOLATED THUNDERSTORM CAN NOT BE RULED OUT FOR
KSME/KLOZ LATER THIS AFTERNOON...BUT SHOULD HAVE FAR LESS
IMPACT/COVERAGE THAN THOSE TO THE NORTH. AS A RESULT...WITHOUT SEEING
ANY ONGOING EVIDENCE OF SHRA/TSRA HEADED TOWARDS THE KSME/KLOZ TAF
SITES...ONLY WENT VCTS AT THIS TIME.
AFTER THE SHOWERS BEGIN TO DIE DOWN THIS EVENING/OVERNIGHT...EXPECT
MOIST ENVIRONMENT TO SPAWN FOG DEVELOPMENT ACROSS MUCH OF THE
AREA AFTER 6Z...ESPECIALLY IN THE VALLEYS. MODELS ARE PEGGING KSME FOR
HAVING THE WORST VIS...BUT DID NOT FEEL CONFIDENT IN GOING BELOW IFR
AT THIS TIME. AS FOG MIXES OUT IN THE MORNING...ANOTHER ROUND OF
CONVECTION WILL DEVELOP. WITH BETTER INSTABILITY IN PLACE...EXPECT
BETTER CHANCES FOR TS DEVELOPMENT AT ALL TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...JJ
LONG TERM...ABE
AVIATION...JMW
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
550 PM EDT SAT JUN 29 2013
.SYNOPSIS...
A STATIONARY FRONT WILL WAVER OVER EASTERN NEW YORK AND WESTERN
NEW ENGLAND OVER THE NEXT SEVERAL DAYS. THIS BOUNDARY WILL ACT AS
A FOCUS FOR SHOWERS AND THUNDERSTORMS KEEPING THE NORTHEAST UNITED
STATES IN AN UNSETTLED WEATHER PATTERN.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
STRONG STORMS CONTINUE TO MOVE ACROSS CENTRAL NH AND CENTRAL
MAINE NEAR AREAS OF DIFFERENTIAL HEATING. WE HAVE RECEIVED REPORTS
OF LARGE HAIL AND DAMAGING WINDS AS THESE MOVE NE. HEAVY RAIN AND
FLOODING ARE ALSO A CONCERN AS CELLS TRAIN OVER THE SAME
LOCATIONS. ROTATION HAS BEEN NOTED...AND WHILE THE STORMS ARE
MOVING INTO AN AREA WITH LOWER LCLS AND BETTER 0-1 KM SHEAR...LACK
OF OVERALL STORM ORGANIZATION WILL KEEP THE TORNADO THREAT LOW.
MUCH OF THE COAST REMAINS IN AN AREA OF CIN THANKS TO CLOUD COVER
AND WILL LIKELY REMAIN PRECIPITATION FREE. ADDITIONAL ISOLATED
CELLS NOW FORMING OVER PORTIONS OF NH HAVE MUCH LESS TO WORK WITH
AND WILL BE RELYING PRIMARILY ON UPSLOPE INFLUENCES.
THE HRRR HAS BEEN TRACKING THIS CONECTIVE EVENT WELL AND HAVE
BASED POPS AND QPF ON ITS OUTPUT FOR THE NEXT FEW HOURS.
&&
.PREVIOUS DISCUSSION...
STRONG SFC HEATING HAS PUSHED THE WARM FNT THRU MOST OF NH AND
NEARBY WRN ME. THIS HAS YIELDED BETWEEN 1000-1500 J/KG CAPE ACROSS
THAT AREA. IN ADDITION...MID LVL JET STREAK IS SUPPORTING 40-50
EFFECTIVE SHEAR...MORE THAN ENOUGH FOR ORGANIZED CONVECTION.
HOWEVER...S/WV TROF HAS RACED ACROSS THE REGION...EFFECTIVELY
LEAVING BEHIND THE BEST INSTABILITY. THE RESULT HAS BEEN
CONVECTION THAT IS MOSTLY DIURNALLY DRIVEN IN NATURE. IT HAS BEEN
TIED TO HIGH TERRAIN FOR INITIATION...AND HAS STRUGGLED AS IT
MOVES NEWD.
GIVEN THE LACK OF STRONGER FORCING MECHANISM...FEEL THAT MOST OF
THE CONVECTION WILL REMAIN DIURNALLY DRIVEN AND WEAKEN QUICKLY
AFTER SUNSET. UNTIL THEN ISOLD TO SCT STRONGER STORMS WILL BE PSBL
IN THIS ENVIRONMENT. STEEP LLVL LAPSE RATES WILL SUPPORT DMGG WIND
GUSTS IN STRONGER STORMS...AS WELL AS MARGINALLY SEVERE HAIL.
STRONG SPEED SHEAR IN THE LOWEST LVLS WILL ALSO SUPPORT A NON-ZERO
TORNADO THREAT...ESPECIALLY NEAR DIFFUSE CONFLUENCE ZONE OVER WRN
NH. THE MAIN THREAT WILL LIKELY BE FLASH FLOODING. HIGH PWAT AIR
MASS REMAINS IN PLACE...AND STORM MOTIONS PARALLEL TO THE SLOWLY
ADVANCING BOUNDARY WILL KEEP THEM TRAINING OVER THE SAME AREAS
AGAIN AND AGAIN. THIS RESULTED IN FLASH FLOODING ACROSS SRN NH
LAST EVENING...AND SEE NO REASON WHY THIS CAN/T OCCUR AGAIN THIS
EVENING.
THE REMNANT CONVECTION WILL DRIFT EWD INTO WRN ME THIS EVENING
BEFORE DISSIPATING COMPLETELY. ONSHORE FLOW AND DIURNAL COOLING
WILL LIKELY BRING MARINE LAYER FOG/STRATUS BACK INTO COASTAL ZONES
AGAIN TONIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
FOR SUNDAY SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON ARE
EXPECT EVEN THOUGH SOME RIDING ALOFT WILL BE MOVING IN. THE
SURFACE BOUNDARY WILL STILL BE TO OUR WEST WITH PLENTY OF MOISTURE
AVAILABLE. SUNDAY NIGHT THE ACTIVITY WILL DECREASE AS WE LOSE THE
SFC HEATING. EXPECT FOG TO DEVELOP AT NIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
UPPER LOW OVER THE MIDWEST AND BERMUDA HIGH WILL KEEP A MOIST
AND WARM SOUTHERLY FLOW OVER THE REGION WITH A SFC BOUNDARY
REMAINING IN PLACE THROUGH AT LEAST MID WEEK. A SHORTWAVE MOVES
NORTH LATE MONDAY AND TUESDAY WITH A 8 TO 12 HOUR HEAVY RAIN
EVENT. PWATS FROM 1.5 TO 2 INCHES. WILL HAVE TO CONTINUE TO
MONITOR RIVERS AND STREAMS AS WE CONTINUE TO SEE A VERY WET JUNE.
THIS JUNE IN PORTLAND IS NOW THE SIXTH WETTEST SINCE 1871.
THE HEAVY RAIN MOVES OUT EARLY TUESDAY BUT IT WILL BE FOLLOWED BY
ANOTHER SHORTWAVE WITH ANOTHER BAND OF HEAVY RAIN MOVING IN LATE
TUESDAY INTO EARLY WEDNESDAY.
A LITTLE MORE RIDING MOVING IN FOR LATER WEDNESDAY AND THURSDAY
BUT AFTERNOON SHOWERS AND THUNDERSTORMS STILL POSSIBLE.
EXPECT ANOTHER SHORTWAVE TO MOVE IN FRIDAY WITH AN AREA OF RAIN/
SHOWERS.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
SHORT TERM...IFR EXPECTED IN ANY SHOWERS/THUNDERSTORMS THIS
AFTERNOON. TONIGHT...IFR OR LOWER CONDITIONS...ESPECIALLY AT THE
COAST...ARE EXPECTED IN LOW CLOUDS AND FOG. CONDITIONS IMPROVE A
BIT DAYTIME SUNDAY. BACK TO IFR IN ANY SHOWERS/THUNDERSTORMS
SUNDAY AFTN THEN IFR IN FOG SUNDAY NIGHT FOG.
LONG TERM...EXPECT IFR MONDAY IN SHOWERS AND THUNDERSTORMS AND IFR
MONDAY NIGHT IN FOG. MORE IFR TUESDAY AS MORE HEAVY RAIN MOVES IN.
EXPECT CONDITIONS TO IMPROVE TO VFR LATE MORNING WED BUT SCATTERED
IFR IN SHOWERS AND THUNDERSTORMS WED AFTERNOON. IFR IN FOG WED
NIGHT. MOSTLY VFR THURSDAY EXCEPT IN ANY AFTERNOON SHOWERS/
THUNDERSTORMS.
&&
.MARINE...
SHORT TERM...SCA FOR ALL ZONES EXCEPT PENOBSCOT BAY THROUGH
SUNDAY. THIS IS FOR SEAS AOA 5 FEET...MAINLY IN SWELLS...ALTHOUGH
THERE WILL BE SOME WIND CONTRIBUTION.
LONG TERM...SCA`S MAY BE NEEDED MONDAY AND TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EDT SUNDAY
FOR ANZ150-152-154.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 PM EDT SAT JUN 29 2013
.SYNOPSIS...
THE COMBINATION OF A WARM AND HUMID AIR MASS OVER THE REGION AND A
LOW PRESSURE TROUGH OVER THE EASTERN STATES WILL RESULT IN UNSETTLED
WEATHER OVER OUR REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 315 PM SATURDAY...
THROUGH TONIGHT: RELATIVE BREAK IN THE NUMEROUS SHOWERS/STORMS SO
FAR TODAY. INSTABILITY HAS BEEN NOTABLY LOWER THAN IN PREVIOUS DAYS
WITH CURRENT MUCAPE AROUND 1000-2000 J/KG AND MLCAPE OF 500-2000
J/KG... LIKELY DUE IN PART TO COOLER LOW LEVEL TEMPS AND DEW POINTS
FROM 925-850 MB AS COMPARED TO PAST DAYS... AND LOWER PW (1.2-1.8
IN. FROM WEST TO EAST ACCORDING TO BLENDED TPW IMAGERY). WE SHOULD
SEE COVERAGE OF SHOWERS AND STORMS RANGING FROM ISOLATED WEST TO
SCATTERED IN THE ERN CWA INTO TONIGHT AS WE REMAIN IN A CYCLONIC
(AND A BIT FAST FOR THIS TIME OF YEAR) MID LEVEL FLOW WITH A WEAK
BUT DISTINCT LOBE OF VORTICITY ROTATING NORTHEAST THROUGH WRN NC/VA
AND ANOTHER PERTURBATION TRACKING UP THE NC COAST. DEEP LAYER SHEAR
WILL REMAIN HIGHER OVER OUR NW (AROUND 40 KTS) AND LOWER DOWN EAST
(25-30 KTS AT MOST) AND IS EXPECTED TO ACTUALLY WEAKEN FURTHER
OVERNIGHT AS THE MID LEVEL WSW WINDS BACK TO SSW AS THE VORTICITY
MAXIMUM DROPPING THROUGH THE MIDWEST DIGS DOWN THROUGH THE WRN OH
VALLEY. SO WITH FURTHER LOWERING OF ALREADY-MARGINAL INSTABILITY
THIS EVENING WITH LOSS OF HEATING (LATEST RAP RUNS TAKE MLCAPE BELOW
800 J/KG OVERNIGHT)... SEVERE WEATHER IS NOT A CONCERN THROUGH
TONIGHT. EXPECT JUST ISOLATED SHOWERS AND PERHAPS A STORM OR TWO
OVERNIGHT OVER ALL BUT THE FAR EASTERN CWA EAST OF I-95 WHERE PW AND
DEEP MOISTURE TRANSPORT ALONG WITH UPPER DIVERGENCE REMAIN ELEVATED
RESULTING IN SLIGHTLY GREATER COVERAGE. STATISTICAL GUIDANCE...
PERSISTENCE... AND THE OVERALL PATTERN SUPPORT REDEVELOPMENT OF LOW
STRATUS TONIGHT ESPECIALLY IN THE CENTRAL/ERN CWA. LOWS 68-73.
FOR SUNDAY/SUNDAY NIGHT: THE PRIMARY WEATHER CONCERN HERE WILL BE
THE THREAT OF HEAVY RAIN AND POSSIBLE FLOODING LATE SUNDAY THROUGH
SUNDAY NIGHT. WEAK SURFACE TROUGHING THROUGH THE PIEDMONT TODAY
LARGELY DISSIPATES BY SUNDAY MORNING WITH A STRENGTHENING OF THE
SURFACE FRONTAL ZONE TO OUR WEST... PLACING CENTRAL NC IN A
UNIFORM SOUTHERLY AND STRENGTHENING LOW LEVEL FLOW. MID LEVEL FLOW
CONTINUES TO BACK AS WELL TO A SSW DIRECTION AS THE POTENT VORTICITY
MAXIMUM CONTINUES TO DROP SOUTHWARD INTO THE MID MISS VALLEY
RESULTING A DEEPENING LONGWAVE TROUGH TO OUR WEST. WITHIN THIS FLOW
THE ANOMALOUSLY HIGH PW VALUES WILL SURGE BACK TO THE NORTH AND NW
THROUGH CENTRAL NC... WITH MODELS INDICATING VALUES NEAR OR ABOVE 2
INCHES... WHICH IS AT OR ABOVE 2 STANDARD DEVIATIONS ABOVE NORMAL.
0-6 KM BULK SHEAR IS EXPECTED TO STRENGTHEN TO 35-45 KTS... BUT
MLCAPE SHOULD PEAK AT JUST 1000-1500 J/KG. NEVERTHELESS... THE SWRLY
UPPER LEVEL JET STRENGTHENS DURING THE DAY TO 100+ KTS FROM ERN KY
THROUGH THE ST LAWRENCE VALLEY... AND THE RESULTING INCREASED UPPER
DIVERGENCE COMBINED WITH MID LEVEL PERTURBATIONS RIDING TO THE NNE
THROUGH NC AND A STRENGTHENING LOW LEVEL SRLY JET TO 25-30 KTS
SHOULD RESULT IN GRADUAL BUT WIDESPREAD STRENGTHENING IN FORCING FOR
ASCENT. THIS LARGE SCALE MODERATE LIFT ACCOMPANYING A SOMEWHAT DEEP
WARM LAYER (LCL TO FREEZING LEVEL DEPTH NEAR 4 KM) SHOULD ALLOW WARM
RAIN PROCESSES TO DOMINATE... FURTHERING THE THREAT OF FLOODING WITH
EXPECTATIONS OF NUMEROUS MULTICELL CLUSTER PRODUCING MODERATE TO
HEAVY RAIN. LATEST SREF OUTPUT SHOWS THAT MOST OF ITS MEMBERS
GENERATE FROM 1 TO 2.5 INCHES OF RAIN OVER THE AREA THROUGH MONDAY
MORNING... AND WHILE THIS RAINFALL BY ITSELF WOULD ORDINARILY NOT
CAUSE WIDESPREAD FLOODING PROBLEMS... THE ANTECEDENT WET GROUND FROM
RECENT RAINS -- ESPECIALLY IN AREAS ALONG AND SOUTH OF HIGHWAY 64 --
ELEVATE THE CONCERNS FOR FLOODING... ESPECIALLY OVER STANLY COUNTY
WHICH HAD FLOODING AFTER RECEIVING SEVERAL INCHES OF RAIN LAST
NIGHT. BUT IT`S DIFFICULT TO DETERMINE PRECISELY WHICH AREAS WILL
RECEIVE THE MORE SUBSTANTIAL RAINFALL OVER A SIZABLE AREA SUNDAY AND
SUNDAY NIGHT. WITH LOW CERTAINTY AS TO THE OCCURRENCE OF WIDESPREAD
HEAVIER AMOUNTS... WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW...
HOWEVER LATER SHIFTS TONIGHT AND SUNDAY MORNING WILL CONSIDER THIS
RISK FURTHER AS WE GET CLOSER TO THE EVENT AND ARE ABLE TO ZERO IN
ON THE LOCATIONS MOSTLY LIKELY TO SEE HEAVY RAIN. SEE HYDROLOGY
SECTION BELOW FOR MORE DETAILS ABOUT RIVER FLOODING POTENTIAL. HIGHS
A TAD LOWER THAN TODAY... 83-86 WITH EARLIER DEVELOPMENT OF
CONVECTIVE CLOUDS. LOWS 68-73.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 255 PM SATURDAY...
THE ANOMALOUS PATTERN WILL CONTINUE THIS WEEK WITH A HIGHLY
AMPLIFIED...QUASI-STATIONARY LONGWAVE TROUGH/RIDGE OVER THE
CONUS. SANDWICHED BETWEEN AN UPPER LOW OVER THE MIDWEST AND AN
STRONG UPPER RIDGE OVER THE WESTERN ATLANTIC...DEEP SOUTHWESTERLY
FLOW WILL CONTINUE PUMP DEEP MOISTURE ACROSS THE CAROLINAS. A
PLUME OF PW IN EXCESS OF 2 INCHES...AND AS HIGH AS 3 STANDARD
DEVIATIONS ABOVE NORMAL BASED ON THE GEFS...WILL SLOWLY SHIFT
WESTWARD MONDAY AND TUESDAY AS THE LONGWAVE RETROGRADES A BIT. AN
UPPER LEVEL JET STRETCHING FROM THE TN VALLEY ACROSS NEE ENGLAND
SUNDAY IS FORECAST TO WEAKEN MONDAY...THEN RE-ENERGIZE OVER THE OH
VALLEY BY TUESDAY AS THE WESTERN ATLANTIC RIDGE STRENGTHENS. LARGE
SCALE FORCING FOR ASCENT IN THE FORM OF UPPER DIVERGENCE AND
BROAD...PERSISTENT ISENTROPIC LIFT WILL BE PERIODICALLY AIDED BY
SUBTLE DISTURBANCES IN THE SOUTHWESTERLY FLOW ALOFT AND DIURNAL
HEATING/DESTABILIZATION...WITH THE MAIN FOCUS FOR QPF SHIFTING FROM
CENTRAL/EASTERN NC TO WESTERN NC BY WEDNESDAY. SREF QPF PLUMES ARE
IN FAIRLY GOOD AGREEMENT ON A WIDESPREAD ONE TO TWO INCHES OF RAIN
THROUGH TUESDAY...AND GEFS SUGGESTS AS MUCH AS 3 INCHES THROUGH
WEDNESDAY. THIS IS GENERALLY IN LINE WITH HPC 5-DAY QPF TOTALS...AND
WITH LOCALLY HIGHER AMOUNTS POSSIBLE DUE TO CONVECTION...A FLASH
FLOOD WATCH WILL MOST LIKELY BE NEEDED.
THE THREAT OF SEVERE WEATHER WILL NOT BE PARTICULARLY HIGH DURING
THE PERIOD DUE TO WEAK LAPSE RATES ALOFT AND GENERALLY WEAK
INSTABILITY. HOWEVER...MODEST SOUTHWESTERLY MID- LEVEL FLOW WILL
STILL SUPPORT CLUSTERS OF CONVECTION AND AN ISOLATED WIND THREAT.
REGARDING TEMPS...THE CONSENSUS OF MODEL GUIDANCE IS FOR HIGHS IN
THE LOW TO MID 80S EACH DAY...ALTHOUGH WIDESPREAD PRECIP COVERAGE
MAY CONCEIVABLY KEEP HIGHS IN THE UPPER 70S IN SOME AREAS. LOWS
WILL BE IN THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 255 PM SATURDAY...
THE UPPER LOW OVER THE MIDWEST IS FORECAST TO CUT OFF BY THE END OF
THE WEEK AND THE POLAR JET RETREATS TO CANADA. THIS WILL LEAVE THE
SOUTHEAST US IN A WEAKER FLOW...SUMMER-LIKE PATTERN DOMINATED BY AN
UPPER RIDGE BUILDING WEST FROM OVER THE ATLANTIC. WITH DRIER AIR
OVER THE CAROLINAS...CONVECTION SHOULD BECOME INCREASINGLY FOCUSED
TO OUR NORTH AND WEST. TEMPS WILL ACCORDINGLY RETURN TO MORE
NORMAL VALUES WITH HIGHS IN THE UPPER 80S AND LOWER 90S.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 105 PM SATURDAY...
SCT-BKN MVFR CLOUDS PERSIST AT RDU/RWI/FAY BUT WILL CONTINUE TO
LIFT.. REACHING VFR BY 19-20Z. BESIDES SOME MVFR VSBYS IN SHOWERS
NEAR RWI 18Z-20Z... THE RISK OF SUB-VFR CONDITIONS FOR THE REMAINDER
OF THE DAY AND EVENING APPEARS SMALL WITH ONLY ISOLATED SHOWERS OR
STORMS WITH A LOW PROBABILITY THAT THESE WILL IMPACT CENTRAL NC TAF
SITES FOR ANY MORE THAN A HALF HOUR. HOWEVER... MORE NUMEROUS STORMS
ARE EXPECTED TO DEVELOP NEAR FAY/RWI AFTER 20Z WHICH COULD BRING
BRIEF MVFR CIGS AND MVFR OR IFR VSBYS WITH HEAVY RAIN AND ISOLATED
WIND GUSTS OVER 30 MPH. OTHERWISE... VFR CONDITIONS WILL HOLD ACROSS
CENTRAL NC PAST NIGHTFALL... BUT MVFR TO IFR STRATUS IS LIKELY TO
DEVELOP AREAWIDE AFTER 07Z TONIGHT. CIGS SHOULD LIFT TO MVFR THEN
VFR BETWEEN 13Z-16Z SUNDAY. NUMEROUS SHOWERS/STORMS ARE EXPECTED TO
DEVELOP ACROSS CENTRAL NC AFTER 16Z.
LOOKING BEYOND 18Z SUNDAY... AS SHOWERS/STORMS BECOME MORE
WIDESPREAD THROUGH SUNDAY AFTERNOON/EVENING... MVFR TO IFR
CIGS/VSBYS ARE LIKELY AT ALL TAF SITES... ALTHOUGH CONSIDERABLE
UNCERTAINTY REMAINS AS THESE SUB-VFR CONDITIONS WILL DEPEND ON
EXACTLY WHERE AND WHEN STORM CLUSTERS DEVELOP. SUB-VFR STRATUS/FOG
SHOULD DOMINATE THROUGH EARLY MON MORNING. PERIODS OF SUB-VFR
CONDITIONS IN SHOWERS/STORMS EACH AFTERNOON/EVENING AND IN
STRATUS/FOG EARLY EACH MORNING THROUGH WEDNESDAY IS EXPECTED... WITH
SOME IMPROVEMENT TOWARD A MORE VFR-DOMINANT PATTERN BY LATE WED INTO
THU. -GIH
&&
.HYDROLOGY...
A DEEP...MOIST SOUTHWESTERLY FLOW WILL SUPPORT SEVERAL PERIODS OF
SHOWERS AND STORMS THROUGH THE MIDDLE OF NEXT WEEK. WIDESPREAD
RAINFALL TOTALS OF ONE TO THREE INCHES ARE EXPECTED DURING THIS
PERIOD...WITH LOCALLY HIGHER AMOUNTS POSSIBLE BEFORE THE WEATHER
PATTERN CHANGES TOWARD THE END OF THE WEEK. WHILE NO RIVER
FLOODING IS ANTICIPATED...MODEL GUIDANCE SUGGEST SOME MODEST RISES
ON MAINSTEM RIVERS WILL BE POSSIBLE. IN ADDITION...LOCALIZED FLASH
FLOODING WILL BE POSSIBLE...PARTICULARLY IN AREAS THAT HAVE
RECEIVED HEAVY RAIN OVER THE PAST COUPLE OF DAYS...INCLUDING THE
SOUTHERN PIEDMONT COUNTIES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
HYDROLOGY...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
256 PM EDT SAT JUN 29 2013
.SYNOPSIS...
THE COMBINATION OF A WARM AND HUMID AIR MASS OVER THE REGION AND A
LOW PRESSURE TROUGH OVER THE EASTERN STATES WILL RESULT IN UNSETTLED
WEATHER OVER OUR REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 1030 AM SATURDAY...
REST OF TODAY THROUGH TONIGHT: LATEST DATA SUPPORTS CONTINUED HIGH
RAIN CHANCES IN THE EAST THIS AFTERNOON INTO TONIGHT... BUT THE
WESTERN HALF OF CENTRAL NC MAY GET A CHANCE TO DRY OUT A LITTLE
TODAY BEFORE MORE RAINS ARRIVE IN THE COMING FEW DAYS. LATEST
SATELLITE AND RADAR IMAGERY SHOWS A BATCH OF SHALLOW LIGHT SHOWERS
OVER NW NC/SW VA FORCED IN PART BY WEAK UPPER DIVERGENCE AND MID
LEVEL DPVA ALONG THE 700 MB FRONT... WHILE ELSEWHERE... MID CLOUDS
STREAKING OFF OF LAST NIGHT`S MCS OVER SRN MS/AL STREAM OVER THE
SOUTHEAST HALF OF THE CWA WHERE LOW LEVEL MOISTURE TRANSPORT REMAINS
ELEVATED SOUTH AND EAST OF THE 850 MB FRONT... AND WHERE ISOLATED
MODERATE SHOWERS PERSIST. THE 850 MB FRONT MADE GOOD EASTWARD
PROGRESS OVERNIGHT WITH THE LOW LEVELS COOLING MARKEDLY... DENOTED
BY 850 MB TEMPS DROPPING FROM 20C TO 16C AT GSO FROM 00Z TO 12Z...
WHICH IS SIGNIFICANT COOLING ESPECIALLY FOR THIS TIME OF YEAR. PW
VALUES HAVE DIPPED AS WELL IN THE WEST WITH READINGS BACK DOWN TO
SEASONAL NORMALS AT GSO NOTED IN THE SOUNDING AND BLENDED TPW
IMAGERY. BUT PW REMAINS HIGH AT 1.8-2.0 INCHES EAST OF THE 850 MB
FRONT... MAINLY ALONG/EAST OF I-95... WHERE PASSAGE OF MID LEVEL
PERTURBATIONS WILL BOOST WHATEVER ASCENT CAN BE ACHIEVED VIA THE
INCREASING BUOYANCY THROUGH THE DAY. THE PRESENCE OF THE MID LEVEL
CLOUDS SHOULD HELP CURB INSTABILITY A BIT... BUT STILL EXPECT MLCAPE
VALUES OF 1500-2000 J/KG ACCORDING TO RECENT RAP RUNS. DEEP LAYER
SHEAR HERE WILL BE LOWER THAN TO THE NORTHWEST... JUST 20-25 KTS...
SO THIS MAY LIMIT ORGANIZATION SOMEWHAT. WILL HAVE LIKELY POPS SE OF
RALEIGH TRENDING TO LOW CHANCES FROM RALEIGH TO THE NW FOR THE REST
OF THE DAYLIGHT HOURS. TEMPS ARE RUNNING A FEW DEGREES BELOW
FORECAST PACE ESPECIALLY THROUGH THE CENTRAL CWA WHERE MID CLOUDS
HAVE HINDERED HEATING. WILL TRIM A DEGREE OR SO OFF HIGHS IN THE
CENTRAL/SE CWA... WITH 84-89 AREAWIDE. THE VORTICITY MAX DROPPING
SOUTHWARD OVER LAKE MICHIGAN INTO IL/IN LATER TODAY WILL LEAD TO
OVERALL LONGWAVE TROUGH AMPLIFICATION TO OUR WEST AND SLOWLY BACKING
WINDS ALOFT OVER NC TONIGHT. INSTABILITY WANES AFTER SUNSET WITH THE
RAP SHOWING MLCAPE UNDER 800 J/KG OVERNIGHT AND LARGE SCALE MODELS
SUGGESTING LITTLE RECOVERY OF HIGHER PW BACK WESTWARD UNTIL LATE
TONIGHT... SO WILL TREND TO LOW CHANCES OF LINGERING SHOWERS
OVERNIGHT MAINLY EAST. LOWS 69-73. -GIH
SUNDAY:
AS ENERGY ALOFT DIVES SOUTHWARD ALONG THE BACKSIDE OF THE TROUGH
ACROSS THE EASTERN HALF OF THE COUNTRY SUNDAY MORNING/SUNDAY... DEEP
SOUTH-SOUTHWESTERLY FLOW WILL INCREASE ACROSS OUR AREA... PUMPING
MORE WARM MOIST AIR INTO CENTRAL NC. THIS WILL LEAD TO LOTS OF
CLOUDS AND INCREASED CONVECTIVE CHANCES. CHANCES OF SHOWERS AND
STORMS WILL BE TIED TO SUBTLE DISTURBANCES MOVING THROUGH THE
SOUTH-SOUTHWESTERLY FLOW ALOFT ALONG WITH AFTERNOON HEATING. MODEL
GUIDANCE CONTINUES TO DEVELOP SCATTERED TO NUMEROUS SHOWERS AND
STORMS ON SUNDAY. THUS... WILL CONTINUE TO ADVERTISE LIKELY POPS ON
SUNDAY AFTERNOON INTO THE EVENING. THE MAIN THREAT WITH THESE
SHOWERS AND STORMS WILL LIKELY BE HEAVY RAIN AND FLASH FLOODING AS
PW`S ARE EXPECTED TO INCREASE TO AROUND THE 2" RANGE. HOWEVER...
DEEP LAYER SHEAR IS EXPECTED TO BE IN THE 25 TO 35 KT RANGE....
THOUGH INSTABILITY MAY BE HAMPERED A BIT BY THE AMOUNT OF CLOUD
COVER. THUS... GIVEN THE POSSIBLE MULTI-CELLAR BAND/CLUSTERS OF
SHOWERS AND STORMS... EXPECT WE MAY HAVE AT LEAST A SMALL DAMAGING
WIND THREAT. EXPECT HIGH TEMPS WILL BE IN THE 84-87 DEGREE RANGE
THANKS TO THE INCREASE IN MOISTURE/STORMS/CLOUDS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 255 PM SATURDAY...
THE ANOMALOUS PATTERN WILL CONTINUE THIS WEEK WITH A HIGHLY
AMPLIFIED...QUASI-STATIONARY LONGWAVE TROUGH/RIDGE OVER THE
CONUS. SANDWICHED BETWEEN AN UPPER LOW OVER THE MIDWEST AND AN
STRONG UPPER RIDGE OVER THE WESTERN ATLANTIC...DEEP SOUTHWESTERLY
FLOW WILL CONTINUE PUMP DEEP MOISTURE ACROSS THE CAROLINAS. A
PLUME OF PW IN EXCESS OF 2 INCHES...AND AS HIGH AS 3 STANDARD
DEVIATIONS ABOVE NORMAL BASED ON THE GEFS...WILL SLOWLY SHIFT
WESTWARD MONDAY AND TUESDAY AS THE LONGWAVE RETROGRADES A BIT. AN
UPPER LEVEL JET STRETCHING FROM THE TN VALLEY ACROSS NEE ENGLAND
SUNDAY IS FORECAST TO WEAKEN MONDAY...THEN RE-ENERGIZE OVER THE OH VALLEY BY
TUESDAY AS THE WESTERN ATLANTIC RIDGE STRENGTHENS. LARGE SCALE
FORCING FOR ASCENT IN THE FORM OF UPPER DIVERGENCE AND
BROAD...PERSISTENT ISENTROPIC LIFT WILL BE PERIODICALLY AIDED BY
SUBTLE DISTURBANCES IN THE SOUTHWESTERLY FLOW ALOFT AND DIURNAL
HEATING/DESTABILIZATION...WITH THE MAIN FOCUS FOR QPF SHIFTING
FROM CENTRAL/EASTERN NC TO WESTERN NC BY WEDNESDAY. SREF QPF
PLUMES ARE IN FAIRLY GOOD AGREEMENT ON A WIDESPREAD ONE TO TWO
INCHES OF RAIN THROUGH TUESDAY...AND GEFS SUGGESTS AS MUCH AS 3
INCHES THROUGH WEDNESDAY. THIS IS GENERALLY IN LINE WITH HPC 5-DAY
QPF TOTALS...AND WITH LOCALLY HIGHER AMOUNTS POSSIBLE DUE TO
CONVECTION...A FLASH FLOOD WATCH WILL MOST LIKELY BE NEEDED.
THE THREAT OF SEVERE WEATHER WILL NOT BE PARTICULARLY HIGH DURING THE
PERIOD DUE TO WEAK LAPSE RATES ALOFT AND GENERALLY WEAK INSTABILITY.
HOWEVER...MODEST SOUTHWESTERLY MID- LEVEL FLOW WILL STILL SUPPORT
CLUSTERS OF CONVECTION AND AN ISOLATED WIND THREAT.
REGARDING TEMPS...THE CONSENSUS OF MODEL GUIDANCE IS FOR HIGHS IN
THE LOW TO MID 80S EACH DAY...ALTHOUGH WIDESPREAD PRECIP COVERAGE
MAY CONCEIVABLY KEEP HIGHS IN THE UPPER 70S IN SOME AREAS. LOWS
WILL BE IN THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 255 PM SATURDAY...
THE UPPER LOW OVER THE MIDWEST IS FORECAST TO CUT OFF BY THE END OF
THE WEEK AND THE POLAR JET RETREATS TO CANADA. THIS WILL LEAVE THE
SOUTHEAST US IN A WEAKER FLOW...SUMMER-LIKE PATTERN DOMINATED BY AN
UPPER RIDGE BUILDING WEST FROM OVER THE ATLANTIC. WITH DRIER AIR
OVER THE CAROLINAS...CONVECTION SHOULD BECOME INCREASINGLY FOCUSED
TO OUR NORTH AND WEST. TEMPS WILL ACCORDINGLY RETURN TO MORE
NORMAL VALUES WITH HIGHS IN THE UPPER 80S AND LOWER 90S.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 105 PM SATURDAY...
SCT-BKN MVFR CLOUDS PERSIST AT RDU/RWI/FAY BUT WILL CONTINUE TO
LIFT.. REACHING VFR BY 19-20Z. BESIDES SOME MVFR VSBYS IN SHOWERS
NEAR RWI 18Z-20Z... THE RISK OF SUB-VFR CONDITIONS FOR THE REMAINDER
OF THE DAY AND EVENING APPEARS SMALL WITH ONLY ISOLATED SHOWERS OR
STORMS WITH A LOW PROBABILITY THAT THESE WILL IMPACT CENTRAL NC TAF
SITES FOR ANY MORE THAN A HALF HOUR. HOWEVER... MORE NUMEROUS STORMS
ARE EXPECTED TO DEVELOP NEAR FAY/RWI AFTER 20Z WHICH COULD BRING
BRIEF MVFR CIGS AND MVFR OR IFR VSBYS WITH HEAVY RAIN AND ISOLATED
WIND GUSTS OVER 30 MPH. OTHERWISE... VFR CONDITIONS WILL HOLD ACROSS
CENTRAL NC PAST NIGHTFALL... BUT MVFR TO IFR STRATUS IS LIKELY TO
DEVELOP AREAWIDE AFTER 07Z TONIGHT. CIGS SHOULD LIFT TO MVFR THEN
VFR BETWEEN 13Z-16Z SUNDAY. NUMEROUS SHOWERS/STORMS ARE EXPECTED TO
DEVELOP ACROSS CENTRAL NC AFTER 16Z.
LOOKING BEYOND 18Z SUNDAY... AS SHOWERS/STORMS BECOME MORE
WIDESPREAD THROUGH SUNDAY AFTERNOON/EVENING... MVFR TO IFR
CIGS/VSBYS ARE LIKELY AT ALL TAF SITES... ALTHOUGH CONSIDERABLE
UNCERTAINTY REMAINS AS THESE SUB-VFR CONDITIONS WILL DEPEND ON
EXACTLY WHERE AND WHEN STORM CLUSTERS DEVELOP. SUB-VFR STRATUS/FOG
SHOULD DOMINATE THROUGH EARLY MON MORNING. PERIODS OF SUB-VFR
CONDITIONS IN SHOWERS/STORMS EACH AFTERNOON/EVENING AND IN
STRATUS/FOG EARLY EACH MORNING THROUGH WEDNESDAY IS EXPECTED... WITH
SOME IMPROVEMENT TOWARD A MORE VFR-DOMINANT PATTERN BY LATE WED INTO
THU. -GIH
&&
.HYDROLOGY...
A DEEP...MOIST SOUTHWESTERLY FLOW WILL SUPPORT SEVERAL PERIODS OF
SHOWERS AND STORMS THROUGH THE MIDDLE OF NEXT WEEK. WIDESPREAD
RAINFALL TOTALS OF ONE TO THREE INCHES ARE EXPECTED DURING THIS
PERIOD...WITH LOCALLY HIGHER AMOUNTS POSSIBLE BEFORE THE WEATHER
PATTERN CHANGES TOWARD THE END OF THE WEEK. WHILE NO RIVER
FLOODING IS ANTICIPATED...MODEL GUIDANCE SUGGEST SOME MODEST RISES
ON MAINSTEM RIVERS WILL BE POSSIBLE. IN ADDITION...LOCALIZED FLASH
FLOODING WILL BE POSSIBLE...PARTICULARLY IN AREAS THAT HAVE
RECEIVED HEAVY RAIN OVER THE PAST COUPLE OF DAYS...INCLUDING THE
SOUTHERN PIEDMONT COUNTIES.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
HYDROLOGY...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
108 PM EDT SAT JUN 29 2013
.SYNOPSIS...
THE COMBINATION OF A WARM AND HUMID AIR MASS OVER THE REGION AND A
LOW PRESSURE TROUGH OVER THE EASTERN STATES WILL RESULT IN UNSETTLED
WEATHER OVER OUR REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1030 AM SATURDAY...
REST OF TODAY THROUGH TONIGHT: LATEST DATA SUPPORTS CONTINUED HIGH
RAIN CHANCES IN THE EAST THIS AFTERNOON INTO TONIGHT... BUT THE
WESTERN HALF OF CENTRAL NC MAY GET A CHANCE TO DRY OUT A LITTLE
TODAY BEFORE MORE RAINS ARRIVE IN THE COMING FEW DAYS. LATEST
SATELLITE AND RADAR IMAGERY SHOWS A BATCH OF SHALLOW LIGHT SHOWERS
OVER NW NC/SW VA FORCED IN PART BY WEAK UPPER DIVERGENCE AND MID
LEVEL DPVA ALONG THE 700 MB FRONT... WHILE ELSEWHERE... MID CLOUDS
STREAKING OFF OF LAST NIGHT`S MCS OVER SRN MS/AL STREAM OVER THE
SOUTHEAST HALF OF THE CWA WHERE LOW LEVEL MOISTURE TRANSPORT REMAINS
ELEVATED SOUTH AND EAST OF THE 850 MB FRONT... AND WHERE ISOLATED
MODERATE SHOWERS PERSIST. THE 850 MB FRONT MADE GOOD EASTWARD
PROGRESS OVERNIGHT WITH THE LOW LEVELS COOLING MARKEDLY... DENOTED
BY 850 MB TEMPS DROPPING FROM 20C TO 16C AT GSO FROM 00Z TO 12Z...
WHICH IS SIGNIFICANT COOLING ESPECIALLY FOR THIS TIME OF YEAR. PW
VALUES HAVE DIPPED AS WELL IN THE WEST WITH READINGS BACK DOWN TO
SEASONAL NORMALS AT GSO NOTED IN THE SOUNDING AND BLENDED TPW
IMAGERY. BUT PW REMAINS HIGH AT 1.8-2.0 INCHES EAST OF THE 850 MB
FRONT... MAINLY ALONG/EAST OF I-95... WHERE PASSAGE OF MID LEVEL
PERTURBATIONS WILL BOOST WHATEVER ASCENT CAN BE ACHIEVED VIA THE
INCREASING BUOYANCY THROUGH THE DAY. THE PRESENCE OF THE MID LEVEL
CLOUDS SHOULD HELP CURB INSTABILITY A BIT... BUT STILL EXPECT MLCAPE
VALUES OF 1500-2000 J/KG ACCORDING TO RECENT RAP RUNS. DEEP LAYER
SHEAR HERE WILL BE LOWER THAN TO THE NORTHWEST... JUST 20-25 KTS...
SO THIS MAY LIMIT ORGANIZATION SOMEWHAT. WILL HAVE LIKELY POPS SE OF
RALEIGH TRENDING TO LOW CHANCES FROM RALEIGH TO THE NW FOR THE REST
OF THE DAYLIGHT HOURS. TEMPS ARE RUNNING A FEW DEGREES BELOW
FORECAST PACE ESPECIALLY THROUGH THE CENTRAL CWA WHERE MID CLOUDS
HAVE HINDERED HEATING. WILL TRIM A DEGREE OR SO OFF HIGHS IN THE
CENTRAL/SE CWA... WITH 84-89 AREAWIDE. THE VORTICITY MAX DROPPING
SOUTHWARD OVER LAKE MICHIGAN INTO IL/IN LATER TODAY WILL LEAD TO
OVERALL LONGWAVE TROUGH AMPLIFICATION TO OUR WEST AND SLOWLY BACKING
WINDS ALOFT OVER NC TONIGHT. INSTABILITY WANES AFTER SUNSET WITH THE
RAP SHOWING MLCAPE UNDER 800 J/KG OVERNIGHT AND LARGE SCALE MODELS
SUGGESTING LITTLE RECOVERY OF HIGHER PW BACK WESTWARD UNTIL LATE
TONIGHT... SO WILL TREND TO LOW CHANCES OF LINGERING SHOWERS
OVERNIGHT MAINLY EAST. LOWS 69-73. -GIH
SUNDAY:
AS ENERGY ALOFT DIVES SOUTHWARD ALONG THE BACKSIDE OF THE TROUGH
ACROSS THE EASTERN HALF OF THE COUNTRY SUNDAY MORNING/SUNDAY... DEEP
SOUTH-SOUTHWESTERLY FLOW WILL INCREASE ACROSS OUR AREA... PUMPING
MORE WARM MOIST AIR INTO CENTRAL NC. THIS WILL LEAD TO LOTS OF
CLOUDS AND INCREASED CONVECTIVE CHANCES. CHANCES OF SHOWERS AND
STORMS WILL BE TIED TO SUBTLE DISTURBANCES MOVING THROUGH THE
SOUTH-SOUTHWESTERLY FLOW ALOFT ALONG WITH AFTERNOON HEATING. MODEL
GUIDANCE CONTINUES TO DEVELOP SCATTERED TO NUMEROUS SHOWERS AND
STORMS ON SUNDAY. THUS... WILL CONTINUE TO ADVERTISE LIKELY POPS ON
SUNDAY AFTERNOON INTO THE EVENING. THE MAIN THREAT WITH THESE
SHOWERS AND STORMS WILL LIKELY BE HEAVY RAIN AND FLASH FLOODING AS
PW`S ARE EXPECTED TO INCREASE TO AROUND THE 2" RANGE. HOWEVER...
DEEP LAYER SHEAR IS EXPECTED TO BE IN THE 25 TO 35 KT RANGE....
THOUGH INSTABILITY MAY BE HAMPERED A BIT BY THE AMOUNT OF CLOUD
COVER. THUS... GIVEN THE POSSIBLE MULTI-CELLAR BAND/CLUSTERS OF
SHOWERS AND STORMS... EXPECT WE MAY HAVE AT LEAST A SMALL DAMAGING
WIND THREAT. EXPECT HIGH TEMPS WILL BE IN THE 84-87 DEGREE RANGE
THANKS TO THE INCREASE IN MOISTURE/STORMS/CLOUDS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 308 AM SATURDAY...
AN ABNORMALLY DEEP UPPER LEVEL TROUGH OVER THE LOWER OH-TN VALLEYS
WILL MAINTAIN A DEEP SLY FLOW OVER THE CAROLINAS SUNDAY NIGHT
THROUGH TUESDAY. THIS FLOW WILL SUPPLY OUR REGION WITH PLENTY OF
WARM TROPICAL AIR AS PRECIP WATER VALUES PROJECTED TO RANGE IN THE
2-2.25 INCH THROUGH THE PERIOD. HEATING OF THIS AIR MASS ALONG WITH
A VORTICITY AXIS EXPECTED TO EXTEND SOUTH-TO-NORTH ACROSS CENTRAL NC
WILL CAUSE NUMEROUS-WIDESPREAD SHOWERS AND
THUNDERSTORMS...ESPECIALLY IN THE AFTERNOON AND EVENING HOURS. DUE
TO THE ORIENTATION OF THE WIND FIELD AND THE MOISTURE LADEN AIR MASS
IN PLACE...SHOWERS AND T-STORMS MAY MOVE REPEATEDLY ACROSS THE SAME
LOCATION. THIS OCCURRENCE MAY LEAD TO FLASH FLOODING...ESPECIALLY IN
URBAN AREAS. PLAN TO CONTINUE TO HIGHLIGHT THIS THREAT IN THE HWO.
OVERNIGHT TEMPS WILL CONTINUE TO BE MUGGY WITH MINIMUM TEMPS IN THE
UPPER 60S-LOWER 70S. EXTENSIVE CLOUD COVERAGE AND ABUNDANT SHOWERS
WILL RESULT IN HIGH TEMPS 3-5 DEGREES BELOW NORMAL. MAX TEMPS
GENERALLY IN THE MID 80S.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 308 AM SATURDAY...
MEDIUM RANGE GUIDANCE CONTINUE TO ADVERTISE A GRADUAL WESTWARD SHIFT
OF THE MAIN MOISTURE PLUME AND ATTENDANT SHEAR AXIS AS SUB-TROPICAL
RIDGE EXTENDS ITS INFLUENCE ONTO THE EASTERN SEABOARD. THIS WOULD
LEAD TO A GRADUAL DECREASE IN CONVECTIVE COVERAGE AS THE AIR MASS
DRIES OUT AND A MID LEVEL INVERSION ASSOCIATED WITH THE BUILDING
HEIGHTS ALOFT CAPS THE ATMOSPHERE. PLAN TO MAINTAIN THE PREVIOUS
FORECAST OF DECREASE POPS..MOST NOTABLE THURSDAY INTO FRIDAY. THE
DECREASE IN CONVECTIVE COVERAGE AND EXTENDED PERIODS OF SUN WILL
WARM AFTERNOON TEMPS BACK INTO THE UPPER 80S TO AROUND 90 BY THE END
OF THE WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 105 PM SATURDAY...
SCT-BKN MVFR CLOUDS PERSIST AT RDU/RWI/FAY BUT WILL CONTINUE TO
LIFT.. REACHING VFR BY 19-20Z. BESIDES SOME MVFR VSBYS IN SHOWERS
NEAR RWI 18Z-20Z... THE RISK OF SUB-VFR CONDITIONS FOR THE REMAINDER
OF THE DAY AND EVENING APPEARS SMALL WITH ONLY ISOLATED SHOWERS OR
STORMS WITH A LOW PROBABILITY THAT THESE WILL IMPACT CENTRAL NC TAF
SITES FOR ANY MORE THAN A HALF HOUR. HOWEVER... MORE NUMEROUS STORMS
ARE EXPECTED TO DEVELOP NEAR FAY/RWI AFTER 20Z WHICH COULD BRING
BRIEF MVFR CIGS AND MVFR OR IFR VSBYS WITH HEAVY RAIN AND ISOLATED
WIND GUSTS OVER 30 MPH. OTHERWISE... VFR CONDITIONS WILL HOLD ACROSS
CENTRAL NC PAST NIGHTFALL... BUT MVFR TO IFR STRATUS IS LIKELY TO
DEVELOP AREAWIDE AFTER 07Z TONIGHT. CIGS SHOULD LIFT TO MVFR THEN
VFR BETWEEN 13Z-16Z SUNDAY. NUMEROUS SHOWERS/STORMS ARE EXPECTED TO
DEVELOP ACROSS CENTRAL NC AFTER 16Z.
LOOKING BEYOND 18Z SUNDAY... AS SHOWERS/STORMS BECOME MORE
WIDESPREAD THROUGH SUNDAY AFTERNOON/EVENING... MVFR TO IFR
CIGS/VSBYS ARE LIKELY AT ALL TAF SITES... ALTHOUGH CONSIDERABLE
UNCERTAINTY REMAINS AS THESE SUB-VFR CONDITIONS WILL DEPEND ON
EXACTLY WHERE AND WHEN STORM CLUSTERS DEVELOP. SUB-VFR STRATUS/FOG
SHOULD DOMINATE THROUGH EARLY MON MORNING. PERIODS OF SUB-VFR
CONDITIONS IN SHOWERS/STORMS EACH AFTERNOON/EVENING AND IN
STRATUS/FOG EARLY EACH MORNING THROUGH WEDNESDAY IS EXPECTED... WITH
SOME IMPROVEMENT TOWARD A MORE VFR-DOMINANT PATTERN BY LATE WED INTO
THU. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
323 PM EDT SAT JUN 29 2013
.SYNOPSIS...
A SLOW MOVING AND UNSEASONABLY STRONG UPPER-LEVEL TROUGH WILL KEEP
UNSETTLED CONDITIONS IN PLACE OVER THE REGION RIGHT INTO THE FIRST
DAYS OF JULY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
WATER VAPOR IMAGERY SHOWS THE LARGE UPPER LOW JUST NORTH OF THE
EASTERN GR LAKES...WITH ANY NUMBER OF MINOR WAVES ROTATING AROUND
IT. VIZ SHOTS SHOW A COUPLE OF AREAS OF ENHANCED CU. THE FIRST IS
WITHIN AN AREA OF LOW LEVEL CONVERGENCE ASSOCIATED WITH A WEAK SFC
TROF FROM NEAR BGM WSW INTO NW PA. THE OTHER IS ARCING UP OUT OF
SW PA INTO THE LAURELS...AND SEEMS ASSOCIATED WITH A TONGUE OF
HIGHER CAPE THAT EXTENDS OUT OF OHIO INTO CENTRAL PA.
RADAR IS BEGINNING TO SHOW SHOWERS DEVELOPING OVER WESTERN
AREAS...WHICH ARE SPREADING SLOWLY NORTHEAST. LOOKS LIKE WE ARE IN
FOR YET ANOTHER DAY OF POP-UP CONVECTION AS SUNSHINE WILL LEAD TO
DESTABILIZATION AND THE DEVELOPMENT OF MORE SCATTERED SHOWERS AND
THUNDERSTORMS. RAP SHOWS BULK SHEAR OF AROUND 30KT OVER MUCH OF
THE REGION. THIS SUGGESTS WE COULD SEE LOCALLY GUSTY WINDS DROP
OUT OF SOME OF THE BETTER ORGANIZED-STRONGER STORMS.
ANY RAIN SHOWERS THIS EVENING WILL BE LIGHT...AND QUICKLY DIMINISH
BY 02-04Z.
THE PRESENCE OF A WEAK SFC RIDGE ACROSS MUCH OF CENTRAL PA
TONIGHT...WILL MEAN WINDS BECOME NEAR CALM WITH INTERVALS OF
CLEARING DEVELOPING. PATCHY FOG WILL ONCE AGAIN DEVELOP AFTER
MIDNIGHT...AND SOME LOCATIONS COULD DROP TO UNDER A MILE FOR A
TIME AROUND AND SHORTLY AFTER SUNRISE ON SUNDAY.
MIN TEMPS WILL RANGE FROM THE MID AND UPPER 50S ACROSS THE
MTNS...TO BETWEEN 60 AND 65F THROUGHOUT THE VALLEYS OF CENTRAL AND
SE PENN.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE RELATIVE RESPITE FROM THE HIGH HUMIDITY WE HAVE BEEN ENJOYING
WILL FADE SUNDAY AS THE UPPER TROUGH RETROGRADES...ALLOWING THE
WESTERN EDGE OF THE ANOMALOUSLY HIGH PWAT AIR TO BEGIN MAKING
INROADS BACK OVER THE FCST AREA.
ONCE AGAIN IT SUGGESTS ANOTHER DAY OF SCATTERED SHOWERS AND
THUNDERSTORMS...BUT WITH MORE MOISTURE AS THE DAY
PROGRESSES...PERHAPS SLIGHTLY HIGHER OVERALL COVERAGE DURING THE
AFTERNOON AND EVENING.
LOCALLY HEAVY RAIN OF OVER 1 INCH PER HOUR COULD EASILY OCCUR
WITHIN THE SLOW MOVING BANDS OF SHOWERS AND STORMS...HOWEVER BASIN
AVERAGE AMTS SHOULD BE 0.50 INCH OR LESS.
MAX TEMPS SUNDAY AFTERNOON WILL BE A FEW...TO PERHAPS SVRL DEG F
BELOW NORMAL IN MOST SPOTS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
MODELS INDICATE THAT UPPER LVL RIDGE WILL SLOWLY WORK WESTWARD
BY LATER NEXT WEEK. THIS WILL CUT DOWN THE CHC OF SHOWERS AND
STORMS BY LATE WEEK.
HOWEVER...PRIOR TO THIS...SHOWERS AND STORMS WILL BE FAIRLY
WIDESPREAD FROM LATE SUNDAY INTO TUE. SOME WITH HEAVY RAIN.
HARD TO PINPOINT AMTS AND TIMING...FOR NOW...WILL KEEP MENTION
IN HWO...AND NOT HAVE A FLOOD WATCH OUT.
TEMPS WILL BE CLOSE TO NORMAL.
MAIN CHANGE TO PACKAGE WAS TO EDGE POPS UP SOME...AND TEMPS.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
SHOWERS ARE BEGINNING TO DEVELOP UNDER THE STRONG LATE JUNE
SUNSHINE...BUT AS OF 2PM STILL NO LIGHTNING OVER MY FCST AREA.
MOST SITES ARE VFR AND WILL REMAIN SO EXCEPT WHILE BEING AFFECTED
BY THE POP UP CONVECTION THAT WILL BECOME MORE WIDESPREAD AS THE
AFTERNOON PROGRESSES.
AN UPPER LEVEL TROUGH OVER THE EASTERN U.S. WILL CONTINUE TO
AMPLIFY THROUGH THE WEEKEND. WITH LITTLE CHANGE IN THE OVERALL
PATTERN...EXPECT UNSETTLED CONDITIONS TO PERSIST WITH DAILY
SHOWERS AND TSTMS...MAINLY IN THE PM HOURS...AND PATCHY LOW
CLOUDS/FOG AT NIGHT.
OUTLOOK...
SUN-THU...VFR WITH AREAS OF LOWER CONDITIONS IN SHOWERS AND
THUNDERSTORMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
231 PM EDT SAT JUN 29 2013
.SYNOPSIS...
A SLOW MOVING AND UNSEASONABLY STRONG UPPER-LEVEL TROUGH WILL KEEP
UNSETTLED CONDITIONS IN PLACE OVER THE REGION RIGHT INTO THE FIRST
DAYS OF JULY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WATER VAPOR IMAGERY SHOWS THE LARGE UPPER LOW JUST NORTH OF THE
EASTERN GR LAKES...WITH ANY NUMBER OF MINOR WAVES ROTATING AROUND
IT. VIZ SHOTS SHOW A COUPLE OF AREAS OF ENHANCED CU. THE FIRST IS
WITHIN AN AREA OF LOW LEVEL CONVERGENCE ASSOCIATED WITH A WEAK SFC
TROF FROM NEAR BGM WSW INTO NW PA. THE OTHER IS ARCING UP OUT OF
SW PA INTO THE LAURELS...AND SEEMS ASSOCIATED WITH A TONGUE OF
HIGHER CAPE THAT EXTENDS OUT OF OHIO INTO CENTRAL PA.
RADAR IS BEGINNING TO SHOW SHOWERS DEVELOPING OVER WESTERN
AREAS...WHICH ARE SPREADING SLOWLY NORTHEAST. LOOKS LIKE WE ARE IN
FOR YET ANOTHER DAY OF POP-UP CONVECTION AS SUNSHINE WILL LEAD TO
DESTABILIZATION AND THE DEVELOPMENT OF MORE SCATTERED SHOWERS AND
THUNDERSTORMS. RAP SHOWS BULK SHEAR OF AROUND 30KT OVER MUCH OF
THE REGION. THIS SUGGESTS WE COULD SEE LOCALLY GUSTY WINDS DROP
OUT OF SOME OF THE BETTER ORGANIZED-STRONGER STORMS.
ANY RAIN SHOWERS THIS EVENING WILL BE LIGHT...AND QUICKLY DIMINISH
BY 02-04Z.
THE PRESENCE OF A WEAK SFC RIDGE ACROSS MUCH OF CENTRAL PA
TONIGHT...WILL MEAN WINDS BECOME NEAR CALM WITH INTERVALS OF
CLEARING DEVELOPING. PATCHY FOG WILL ONCE AGAIN DEVELOP AFTER
MIDNIGHT...AND SOME LOCATIONS COULD DROP TO UNDER A MILE FOR A
TIME AROUND AND SHORTLY AFTER SUNRISE ON SUNDAY.
MIN TEMPS WILL RANGE FROM THE MID AND UPPER 50S ACROSS THE
MTNS...TO BETWEEN 60 AND 65F THROUGHOUT THE VALLEYS OF CENTRAL AND
SE PENN.
&&
.SHORT TERM /SUNDAY/...
THE RELATIVE RESPITE FROM THE HIGH HUMIDITY WE HAVE BEEN ENJOYING
WILL FADE SUNDAY AS THE UPPER TROUGH RETROGRADES...ALLOWING THE
WESTERN EDGE OF THE ANOMALOUSLY HIGH PWAT AIR TO BEGIN MAKING
INROADS BACK OVER THE FCST AREA.
ONCE AGAIN IT SUGGESTS ANOTHER DAY OF SCATTERED SHOWERS AND
THUNDERSTORMS...BUT WITH MORE MOISTURE AS THE DAY
PROGRESSES...PERHAPS SLIGHTLY HIGHER OVERALL COVERAGE DURING THE
AFTERNOON AND EVENING.
LOCALLY HEAVY RAIN OF OVER 1 INCH PER HOUR COULD EASILY OCCUR
WITHIN THE SLOW MOVING BANDS OF SHOWERS AND STORMS...HOWEVER BASIN
AVERAGE AMTS SHOULD BE 0.50 INCH OR LESS.
MAX TEMPS SUNDAY AFTERNOON WILL BE A FEW...TO PERHAPS SVRL DEG F
BELOW NORMAL IN MOST SPOTS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
GUIDANCE CONTINUES TO ADVERTISE A TREND TOWARD A MORE TYPICAL
SUMMER PATTERN BY THE END OF NEXT WEEK...FOLLOWING THE HIGHLY
AMPLIFIED WRN RIDGE/ERN TROUGH CONFIGURATION IN PLACE OVER THE
CONUS FROM THE SHORT TERM TO START OF THE MEDIUM RANGE PERIOD.
OVERALL...THE EXTENDED FORECAST IS STILL MANUFACTURED OUT OF THE
DEPARTMENT OF REDUNDANCY DEPARTMENT - WITH CHC OF SHOWERS/TSTMS ON
A DAILY BASIS.
THERE IS ALSO TRENDING NOTED WITH THE WRN ATLC/BERMUDA UPPER
RIDGE TOWARD A SOMEWHAT STRONGER SOLUTION OR AT LEAST A GREATER
RETROGRESSION WITH TIME. MODEL AND ENSEMBLE DATA HAS BEEN VERY
CONSISTENT IN SHOWING AN ATM RIVER/ANOMALOUS PRECIPITABLE WATER
VALUES BEING DRAWN NWD BTWN THE UPPER TROUGH MIGRATING INTO THE MS
VLY AND THE UPPER RIDGE PUSHING WWD FROM THE EASTERN SEABOARD.
THIS WILL MAKE FOR AN INTERESTING FORECAST AS THE DEEP PLUME OF
TROPICAL MOISTURE APPEARS TO INTERACT WITH A FRONTAL ZONE TO
PRODUCE AN AREA OF ORGANIZED MOD-HVY RAINFALL SOMEWHERE OVER THE
MID-ATLC REGION. BY F144 OR 00Z FRI 7/5...THE OPRN GFS/CMC/EC AND
GEFS MEAN SHOW AN AVG OF 1-2 INCHES OF RAIN OVER CENTRAL PA WITH
SOME LOCALLY HIGHER AMTS IN THE 2-4 INCH RANGE. THE DETAILS WILL
NEED TO BE RESOLVED AT SHORTER RANGES...BUT THE SYNOPTIC SCALE
PATTERN LOOKS FAVORABLE FOR SIGNIFICANT RAINFALL THAT MAY LEAD TO
POTENTIAL FLOODING. THEREFORE WE FELT CONFIDENT ENOUGH TO MENTION
THIS IN THE HWO PRODUCT.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
SHOWERS ARE BEGINNING TO DEVELOP UNDER THE STRONG LATE JUNE
SUNSHINE...BUT AS OF 2PM STILL NO LIGHTNING OVER MY FCST AREA.
MOST SITES ARE VFR AND WILL REMAIN SO EXCEPT WHILE BEING AFFECTED
BY THE POP UP CONVECTION THAT WILL BECOME MORE WIDESPREAD AS THE
AFTERNOON PROGRESSES.
AN UPPER LEVEL TROUGH OVER THE EASTERN U.S. WILL CONTINUE TO
AMPLIFY THROUGH THE WEEKEND. WITH LITTLE CHANGE IN THE OVERALL
PATTERN...EXPECT UNSETTLED CONDITIONS TO PERSIST WITH DAILY
SHOWERS AND TSTMS...MAINLY IN THE PM HOURS...AND PATCHY LOW
CLOUDS/FOG AT NIGHT.
OUTLOOK...
SUN-THU...VFR WITH AREAS OF LOWER CONDITIONS IN SHOWERS AND
THUNDERSTORMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...STEINBUGL
AVIATION...LA CORTE
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
107 PM CDT SAT JUN 29 2013
.UPDATE...
18Z AVIATION DISCUSSION UPDATED BELOW.
&&
.SHORT TERM...TODAY THROUGH MONDAY
CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS A VORT MAX
MOVING SOUTH ACROSS SOUTHERN CANADA READY TO CROSS THE
INTERNATIONAL BORDER. THIS IS THE WAVE THAT WILL MOVE OVER THE
REGION TODAY AND BRING ISO/WDLY SCT SHOWERS AND THUNDERSHOWERS.
MODELS ALSO SHOWING A SUBTLE BACK DOOR COOL FRONT SLIDING
SOUTHWEST INTO THE NORTHEASTERN CWA WHICH WILL HELP TO AID IN
SHOWER DEVELOPMENT. MLCAPE VALUES ARE VERY LOW AND ONLY MAX OUT
AROUND 500 TO 600 J/KG ACROSS THE EASTERN CWA. MOST ALL HI RES
MODELS SHOWING DEVELOPMENT OF SMALL SHOWERS/THUNDERSHOWERS BY
AROUND 18Z AND PUSHES THEM AS FAR WEST AS THE JAMES VALLEY AND
EVEN A TAD FURTHER WEST. EXPECT THAT ANY ACTIVITY WILL DIMINISH
THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
THE REST OF THE SHORT TERM LOOKS RATHER QUITE WITH SURFACE HIGH
PRESSURE IN CONTROL OF THE WEATHER. WINDS WILL BE RATHER LIGHT
WITH PLEASANT TEMPERATURES. CONDITIONS LOOK TO BE DRY WITH PRECIP
CHANCES NOT INCREASING UNTIL LATER ON IN THE EXTENDED PERIOD.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT
THE LONGER RANGE MODEL SOLUTIONS ARE CERTAINLY LESS THAN
CONSISTENT WITH HANDLING UPPER LEVEL FLOW PATTERN EVOLUTION. THE
LATEST INSTALLMENT OF 00Z SOLUTIONS HAS THE MAMMOTH UPPER LEVEL
RIDGE OVER THE WEST FLATTENING OUT BY THURSDAY...WITH STRONGER
WESTERLIES AND EMBEDDED S/W`S MOVING SWIFTLY EASTWARD ACROSS THE
PACIFIC NORTHWEST OVER INTO THE NORTHERN PLAINS BY THE END OF NEXT
WEEK. DOUBTLESS...WHEN THE ALLBLEND POPS GET BOILED DOWN...THERE
WILL BE AT LEAST A COUPLE PERIODS IN THE EXTENDED WITH
PRECIPITATION CHANCES.
AT THIS POINT...TEMPERATURE TRENDS APPEAR TO BE COOLER EARLIER ON
IN THE PERIOD WITH A GRADUAL LOW LEVEL WAA/WARMING TREND HEADING
INTO THURSDAY/FRIDAY.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
SURFACE HEATING CU DEVELOPING QUICKLY EARLY THIS AFTERNOON ALONG
WITH A FEW SHOWERS SHOWN ON RADAR. EXPECT THE CU TO BE LOW VFR AND
GO FROM SCT-BKN AT TIMES AT ALL TERMINALS THIS AFTERNOON INTO
EARLY EVENING WITH SOME VICINITY SHOWERS AT ABR AND ATY. ABR AND
ATY MAY ALSO EXPERIENCE A P6SM -SHRA AT THE STATION.
OTHERWISE...THE NORTH TO NORTHEAST WINDS WILL BE BREEZY AT ALL
TERMINALS TODAY AROUND 15 KNOTS GUSTING TO 20 TO 25 KNOTS. THE
CLOUDS WILL DISSIPATE THIS EVENING ALONG WITH WINDS BECOMING LIGHT
UNDER CLEAR SKIES AS SURFACE HIGH PRESSURE RIDGING REMAINS OVER
THE REGION.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...TMT
LONG TERM...DORN
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
310 PM CDT SAT JUN 29 2013
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 310 PM CDT SAT JUN 29 2013
DATA ANALYSIS OF LATEST SATELLITE IMAGERY INCLUDING WATER
VAPOR/IR/VISIBLE SHOWS A MID-LEVEL TROUGH ROTATING SOUTHWARD ACROSS
THE AREA THIS AFTERNOON. RADAR MOSAIC SHOWING SCATTERED TO NUMEROUS
SHOWERS WITH PERHAPS AN ISOLATED THUNDERSTORM ACROSS THE AREA
ASSOCIATED WITH THIS TROUGH. AS A RESULT OF THE COOLER AIR
ALOFT/SHOWER ACTIVITY...TEMPERATURES THIS AFTERNOON BEING HELD DOWN
IN THE MIDDLE 60S TO LOWER 70S.
LOOK FOR THE TROUGH TO CONTINUE ROTATING SOUTH AND OUT OF THE AREA
THIS EVENING WITH SUBSIDENCE FILLING IN BEHIND AS A RIDGE OF HIGH
PRESSURE BUILDS IN. CARRIED ISOLATED-SCATTERED SHOWERS/ISOLATED
THUNDER SOUTH OF I-90...THEN DIMINISHING COMPLETELY BY 9-10 PM.
OTHERWISE...SKIES ARE EXPECTED TO CLEAR FROM NORTH TO SOUTH THROUGH
THE NIGHT WITH LOWS BOTTOMING OUT IN THE UPPER 40S ACROSS PARTS OF
NORTHERN/CENTRAL WI...TOT HE LOWER/MID 50S ELSEWHERE. THERE COULD BE
SOME PATCHY FOG OVER THE LOWER LYING CRANBERRY BOG COUNTRY OF
CENTRAL WISCONSIN. HOWEVER...LIGHT NORTHEAST SURFACE WINDS AROUND 5
MPH RANGE IS EXPECTED TO KEEP LOWER BOUNDARY LAYER STIRRED ENOUGH TO
PREVENT ANY WIDESPREAD FOG FORMATION.
OTHER THAN A FEW CUMULUS EXPECTED TO DEVELOP SUNDAY IN DAYTIME
HEATING...SKIES ARE EXPECTED TO BE MOSTLY SUNNY WITH HIGHS TOPPING
OFF IN THE UPPER 70S/AROUND 80. ALSO OF NOTE WILL BE FAIRLY
DRY/PLEASANT HUMIDITY LEVELS IN THE 35-45 PERCENT RANGE.
SURFACE/MID-LEVEL RIDGE OF HIGH PRESSURE WILL BE OVER THE AREA SUNDAY
NIGHT FOR CLEAR AND COOL CONDITIONS. PLAN ON OVERNIGHT LOWS IN THE
50-55 DEGREE RANGE. CLEAR/COOL CONDITIONS COULD LEAD TO SOME FOG
DEVELOPMENT IN LOWER LYING/RIVER VALLEYS. WILL PUT A MENTION OF
PATCHY IN FOG FOR NOW...BUT THIS WILL HAVE TO BE WATCHED FOR
POSSIBLY BEING MORE WIDESPREAD/DENSE. MITIGATING FACTORS FOR
WIDESPREAD FOG WILL BE A GOOD DRYING DAY SUNDAY AND LIGHT NORTH
WINDS OVERNIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM CDT SAT JUN 29 2013
MODELS SHOW THE TROUGH TO THE SOUTHEAST STARTS RETROGRADING BACK TO
THE NORTHWEST TOWARD US ON MONDAY. SLIGHTLY COOLER CYCLONIC FLOW ALOFT
WORKS BACK INTO THE AREA WITH THE GFS AND NAM BOTH SHOWING SOME
LIGHT QPF BREAKING OUT ACROSS NORTHERN WI. WITH THE LACK OF ANY
OBVIOUS SURFACE/MID-LEVEL FORCING MECHANISMS...THINKING THAT THIS
MAY BE THE RESULT OF A LAKE SUPERIOR BREEZE INFLUENCE COMBINED WITH
THE STEEPENING LOWER LEVEL LAPSE RATES. WILL KEEP MONDAY DRY FOR
NOW...BUT WILL HAVE TO CONTINUE TO WATCH FOR THIS FEATURE FOR
POSSIBLE INCLUSION OF SOME SHOWERS OVER THE NORTH.
FOR TUESDAY/TUESDAY NIGHT...GFS/ECMWF/GEM/NAM ALL SHOW THE MID-LEVEL
TROUGH FORMING A CLOSED LOW AND CONTINUING TO RETROGRADE
NORTHWESTWARD INTO THE AREA. BASED ON THIS SIGNAL...INTRODUCED A
SLIGHT CHANCE FOR SHOWERS/ISOLATED THUNDER TUESDAY FOR MAINLY SOUTH
OF I-90 TUESDAY...AND THEN SHOWERS CHANCES ACROSS THE ENTIRE TUESDAY
NIGHT.
MODELS THEN SHOW THE CLOSED LOW OPENING/FILLING AS IT LIFTS NORTH
THROUGH THE AREA WEDNESDAY/WEDNESDAY NIGHT. LINGERING COOL/CYCLONIC
FLOW ASSOCIATED WITH THE TROUGH ENOUGH TO GENERATE A FEW
SHOWERS/ISOLATED THUNDER.
FOR THURSDAY THROUGH SATURDAY...GENERAL TROUGHINESS LINGERS ACROSS
THE AREA FOR CONTINUED SMALL-END CHANCES OF MAINLY DAYTIME SHOWERS
AND ISOLATED THUNDERSTORMS.
TEMPERATURE-WISE...EXPECTING HIGHS TO BE IN THE 75-80 DEGREE RANGE
FROM MONDAY THROUGH THURSDAY...THEN WARMING INTO THE LOWER/MIDDLE
80S FRIDAY AND SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED
AT 1154 AM CDT SAT JUN 29 2013
SHORT WAVE TROUGH EVIDENT ON WATER VAPOR SATELLITE OVER CENTRAL
WISCONSIN LATE THIS MORNING. THE 29.15Z RAP SUGGESTS THIS WILL BE
THE LAST SHORT WAVE TROUGH TO IMPACT THE AREA FROM THE UPPER LEVEL
LOW OVER THE GREAT LAKES REGION. THE SHOWERS WITH THE WAVE MOVING
ACROSS THE AREA LATE THIS MORNING ARE EXPECTED TO CONTINUE MOVING
SOUTH/SOUTHWEST AND SHOULD CLEAR THE TAF SITES BY MID AFTERNOON.
HAVE CARRIED A TEMPO GROUP FOR BOTH SITES TO SHOW THE POTENTIAL
FOR MVFR CONDITIONS WITH THESE SHOWERS THEN GOING BACK UP TO VFR
FOR THE REMAINDER OF THE AFTERNOON. COULD STILL BE A FEW LINGERING
SHOWERS FOR THE LATE AFTERNOON SO CARRIED A VCSH UNTIL 00Z.
SATELLITE AND OBSERVATIONS SHOWING THE CLOUDS SCATTERING OUT NEAR
LAKE SUPERIOR IN THE SUBSIDENT ZONE BEHIND THE WAVE AND THIS WILL
SPREAD OVER THE AREA THIS EVENING. MOVED UP THE TIMING FROM THE
PREVIOUS FORECAST AND CONCERNED THIS MAY STILL BE TOO SLOW. WITH
THE RECENT MOISTURE AND THE CLOUDS CLEARING OUT THIS EVENING SOME
POTENTIAL FOR FOG OVERNIGHT. THE 29.12Z NAM BUFKIT SOUNDINGS DOES
SHOW SURFACE SATURATION OCCURRING LATE TONIGHT BUT EXPECTING THE
WINDS TO REMAIN AT OR ABOVE 5 KNOTS AND TO CREATE JUST ENOUGH
MIXING TO KEEP THE FOG FROM FORMING. HIGH PRESSURE THEN BUILDS IN
FOR SUNDAY WITH LITTLE OR NO CLOUDS AND A NORTH TO NORTHEAST WIND
AROUND 10 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1154 AM CDT SAT JUN 29 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 230 AM CDT SAT JUN 29 2013
LATEST WATER VAPOR IMAGERY DEPICTED AN UPPER LEVEL SHORTWAVE SLIDING
SOUTH/SOUTHEAST ACROSS MN...WITH ANOTHER...WEAKER FEATURE SPINNING
OVER THE UP OF MICH. CURRENT SHOWERS OVER EASTERN MN SEEM TO BE
ASSOCIATED WITH THE SHORTWAVE IN THAT REGION.
THIS FEATURE WILL CONTINUE ITS GRADUALLY SINK SOUTHWARD
TODAY...WHILE THE UP MICH SHORTWAVE SLIPS ACROSS THE FORECAST AREA
FOR THE AFTERNOON HOURS. FRONTOGENETIC FIELDS HINT A SFC TROUGH
WILL ACCOMPANY THIS SHORTWAVE. MUCAPES OF 500-1000 J/KG ARE
SUGGESTED BY THE GFS/NAM FOR THE AFTERNOON/EARLY EVENING
HOURS...ASSUMING OF COURSE THAT THERE WILL BE ENOUGH BREAKS IN CLOUD
COVER TO ALLOW FOR ATMOSPHERIC RECOVERY FROM THE EARLY MORNING
SHOWERS. BUFKIT SOUNDINGS AGAIN POINT TO SKINNY CAPE...SO CONVECTIVE
UPDRAFTS WOULD BE RELATIVELY SUBDUED...LIMITING A SEVERE THREAT.
LITTLE IF ANY 0-6 KM SHEAR TOO. EXPECTING ON AND OFF SHOWERS THROUGH
THE DAY...SHIFTING NORTH TO SOUTH. ISOLATED THUNDERSTORMS ARE ALSO
POSSIBLE...WITH SOME ENHANCED GUSTINESS AROUND THE STORMS. BRIEF
DOWNPOURS ARE ALSO LIKELY...BUT NOT THE KIND THAT WOULD RESULT IN
FLASH FLOODING OR FURTHER FLOODING PROBLEMS. MOST OF THE SHOWER
ACTIVITY SHOULD BE SOUTH OF I-90 BY EARLY EVENING...EXITING THE
FORECAST AREA BY MID EVENING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 230 AM CDT SAT JUN 29 2013
WEST COAST RIDGE/EAST COAST TROUGH HOLDS ACROSS THE U.S. FOR THE
EARLY PART OF THE NEW WEEK...IN A QUASI-REX BLOCK FORMATION. AT THE
SFC...HIGH PRESSURE IS STILL PROGGED TO DROP SOUTHWARD OUT OF CANADA
AND ACROSS THE GREAT LAKES SUNDAY NIGHT...SLOWLY SINKING SOUTHEAST
BY MID WEEK. THE GFS BUILDS MLCAPES AROUND 1000 J/KG SUN-FRI...BUT
LITTLE IF ANY WIND SHEAR. STILL...SUGGESTIVE OF A CONVECTIVE
POTENTIAL IF A FOCUS CAN BE FOUND. DON/T SEE ANY FRONTOGENETIC
FORCING TO WORK WITH...BUT THERE COULD BE BITS OF UPPER LEVEL ENERGY
THAT SPIN ACROSS THE UPPER MISSISSIPPI RIVER VALLEY AS THE UPPER
LEVEL LOW ASSOCIATED WITH THE TROUGH HOVERS OVER THE REGION. THE GFS
PRODUCES LIGHT QPF ACROSS THE AREA EVERY DAY...BUT IT DOESN/T SEEM
TO BE ASSOCIATED WITH A BOUNDARY OR UPPER LEVEL FEATURE. RATHER...IT
LOOKS MORE IN RESPONSE TO THE BUILDING INSTABILITY THROUGH THE
DAYTIME HOURS...AUTO-CONVECTING. THE ECMWF STAYS DRY...EXCEPT IN THE
CASES WHEN IT LATCHES ONTO A DISTINCTIVE UPPER LEVEL SHORTWAVE...AS
IT DOES ON WED. CONFIDENCE LOW ON RAIN CHANCES FOR THE UPCOMING
WEEK...BUT IF ANY TIME WAS FAVORED...IT WOULD BE DURING THE
AFTERNOON/EARLY EVENING HOURS. PROBABLY NO MORE THAN SLIGHT CHANCES
AT THIS TIME. WILL LIKELY LEAN ON A DRY NIGHT TIME PERIOD...WITH
SMALL POPS DURING THE DAY...UNTIL A MORE DEFINITIVE SOURCE FOR
FORCING CAN BE EVIDENCED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1154 AM CDT SAT JUN 29 2013
SHORT WAVE TROUGH EVIDENT ON WATER VAPOR SATELLITE OVER CENTRAL
WISCONSIN LATE THIS MORNING. THE 29.15Z RAP SUGGESTS THIS WILL BE
THE LAST SHORT WAVE TROUGH TO IMPACT THE AREA FROM THE UPPER LEVEL
LOW OVER THE GREAT LAKES REGION. THE SHOWERS WITH THE WAVE MOVING
ACROSS THE AREA LATE THIS MORNING ARE EXPECTED TO CONTINUE MOVING
SOUTH/SOUTHWEST AND SHOULD CLEAR THE TAF SITES BY MID AFTERNOON.
HAVE CARRIED A TEMPO GROUP FOR BOTH SITES TO SHOW THE POTENTIAL
FOR MVFR CONDITIONS WITH THESE SHOWERS THEN GOING BACK UP TO VFR
FOR THE REMAINDER OF THE AFTERNOON. COULD STILL BE A FEW LINGERING
SHOWERS FOR THE LATE AFTERNOON SO CARRIED A VCSH UNTIL 00Z.
SATELLITE AND OBSERVATIONS SHOWING THE CLOUDS SCATTERING OUT NEAR
LAKE SUPERIOR IN THE SUBSIDENT ZONE BEHIND THE WAVE AND THIS WILL
SPREAD OVER THE AREA THIS EVENING. MOVED UP THE TIMING FROM THE
PREVIOUS FORECAST AND CONCERNED THIS MAY STILL BE TOO SLOW. WITH
THE RECENT MOISTURE AND THE CLOUDS CLEARING OUT THIS EVENING SOME
POTENTIAL FOR FOG OVERNIGHT. THE 29.12Z NAM BUFKIT SOUNDINGS DOES
SHOW SURFACE SATURATION OCCURRING LATE TONIGHT BUT EXPECTING THE
WINDS TO REMAIN AT OR ABOVE 5 KNOTS AND TO CREATE JUST ENOUGH
MIXING TO KEEP THE FOG FROM FORMING. HIGH PRESSURE THEN BUILDS IN
FOR SUNDAY WITH LITTLE OR NO CLOUDS AND A NORTH TO NORTHEAST WIND
AROUND 10 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04