Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/04/14
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
309 PM MDT TUE SEP 2 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 308 PM MDT TUE SEP 2 2014
ALL IS QUIET ON THE WESTERN FRONT THIS AFTERNOON. A BIT OF CUMULUS
HAS DEVELOPED OVER THE HIGH COUNTRY ABOUT AS EXPECTED WHICH SHOULD
DISSIPATE WITH THE SETTING SUN. LITTLE IN THE WAY OF QUASI-
GEOSTROPHIC DYNAMICS EXPECTED THROUGH THE PERIOD. PRECIPITABLE
WATER VALUES ARE FORECAST TO BE A BIT HIGHER TOMORROW THAN IS THE
CASE TODAY BUT STILL NOTHING TO GET EXCITED ABOUT...MAYBE SOME
MORE CUMULUS THAN TODAY. THE CIRA WRF SIMULATED SATELLITE IMAGERY
DEPICTS SOME STRATUS OVER LINCOLN COUNTY AND ITS ENVIRONS AROUND
SUNRISE WEDNESDAY...SIMILAR TO TODAY...AND HAVE INCLUDED THIS IN
THE GRIDS.
THE MAIN ISSUE FOR TOMORROW IS AN INCREASE IN THE WINDS AND THE
ABOVE NORMAL HIGH TEMPERATURES DUE TO INCREASING PRESSURE
GRADIENTS AND DOWNSLOPE COMPONENT. BEASTLY 90+ READINGS ARE
EXPECTED AT LOWER ELEVATIONS WITH ABOVE NORMAL MAXIMA IN THE HIGH
COUNTRY AS WELL. OFFICIAL RECORD HIGH OF 95 AT DIA SET IN 1995
COULD BE THREATENED. LOW HUMIDITIES IN AND CLOSE TO THE MOUNTAINS
WILL COMBINE WITH THE WINDS TO ELEVATE THE FIRE DANGER ESPECIALLY
IN SOUTH PARK. NO PLANS FOR FIRE WEATHER HIGHLIGHTS AT THIS TIME.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 308 PM MDT TUE SEP 2 2014
DRY WEATHER WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT AND MOST
OF THURSDAY. BY LATE THURSDAY...MID/UPPER LEVEL MOISTURE BEGINS
TO INCREASE IN/NEAR THE MOUNTAINS BY LATE IN THE DAY. THE LOW
LEVELS ARE QUITE STABLE SO ANY CONVECTIVE SHOWERS/STORMS THAT
DEVELOP IN THE HIGH COUNTRY WILL LIKELY DISSIPATE AS THEY ATTEMPT
TO MOVE INTO THE LOWER ELEVATIONS OF THE PLAINS. HAVE TRIMMED BACK
THE EASTERN EXTENT OF THE ALREADY LOW POPS...BUT SOME FURTHER
REFINEMENT COULD BE NECESSARY TO REMOVE THEM FROM THE I-25
CORRIDOR AS WELL. FOR NOW...HAVE KEPT LOW POPS IN CONSIDERING OUR
PROXIMITY TO THE RIGHT REAR ENTRANCE REGION OF DEPARTING UPPER
LEVEL SPEED MAX.
ON FRIDAY AND SATURDAY...SURFACE HIGH PRESSURE BUILDS OVER THE
CENTRAL PLAINS. THIS WILL KEEP A RELATIVELY COOL AND SLIGHTLY
STABLE AIRMASS ACROSS MOST OF THE COLORADO PLAINS. AT THE SAME
TIME...THERE IS A MODEST THETA-E RIDGE BUILDING ALONG THE FRONT
RANGE AND OVER THE MOUNTAINS...WHICH SHOULD BRING SCATTERED
SHOWER/STORM DEVELOPMENT EACH AFTERNOON AND EVENING. WOULD EXPECT
A FEW OF THESE TO DRIFT ONTO THE PLAINS EACH LATE
AFTERNOON/EVENING AS WELL...WITH A WEAKER CAP AND AGAIN THE CLOSE
PROXIMITY OF THE UPPER LEVEL SPEED MAX. TEMPERATURES SHOULD REMAIN
A FEW DEGREES BELOW NORMAL ON THE PLAINS WITH THE COOLER HIGH
PRESSURE AND LIGHT EASTERLY UPSLOPE FLOW ACROSS THE HIGH PLAINS.
ON SUNDAY...WEAK LEE TROUGHING WILL LIKELY DEVELOP AS CENTRAL
PLAINS HIGH PRESSURE RETREATS TO THE EAST. THIS SHOULD ALLOW
TEMPERATURES TO REBOUND TO NEAR NORMAL TEMPERATURES. CAPES MAY
ALSO INCREASE WITH SOUTHERLY LOW LEVEL FLOW AND INCREASED LOW
LEVEL MOISTURE...RESULTING IN A FEW STRONGER STORMS. OVERALL...
THE FORECAST AREA REMAINS ON THE NORTHERN EDGE OF ANY DEEPER
MONSOONAL MOISTURE SO THE THREAT OF ANY HEAVY RAINFALL IS LOW
DUE TO EXPECTED FASTER STORM MOTIONS AND LIMITED PRECIPITABLE
WATER.
BY LATE MONDAY OR TUESDAY...WE SEE SOME POTENTIAL FOR DRYING WITH
A LARGER TROUGH MOVING IN FROM THE PACIFIC NORTHWEST. THIS WOULD
SWEEP ANY DEEPER MOISTURE TO THE EAST AND LOWER THE CHANCE OF ANY
SHOWERS/STORMS. TIMING IS SOMEWHAT UNCERTAIN HERE WITH THE LATEST
12Z ECMWF SHOWING A SLOWER EASTWARD ADVANCEMENT OF THIS TROUGH.
&&
.AVIATION...(FOR THE TAFS THROUGH 00Z WEDNESDAY LATE AFTERNOON)
ISSUED AT 308 PM MDT TUE SEP 2 2014
CAVOK THROUGH WEDNESDAY. A WEAK WESTERLY PUSH SWUNG THE WINDS
AROUND TO WESTERLY AT KDEN. THE FEATURE SHOWS UP ON THE DOPPLER
VELOCITY BUT IT IS NOT CLEAR WHAT IT IS. THE HRRR HAS A HINT OF IT
BUT IT WASHES OUT LATER THIS AFTERNOON WITH EAST SOUTHEASTERLIES
REFORMING. THE OTHER TWO TERMINALS WERE LESS IMPACTED BY THIS.
DRAINAGE FLOW EXPECTED TO FORM OVERNIGHT WHICH MAY BE A ENHANCED
JUST A BIT LATE TONIGHT AS LOW PRESSURE DEVELOPS TO OUR NORTHEAST.
EXPECTING GENERALLY LIGHT FLOW TOMORROW WHICH SHOULD FAVOR A
SOUTHWESTERLY DIRECTION.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...ET
LONG TERM...BARJENBRUCH
AVIATION...ET
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1110 PM MDT MON SEP 1 2014
.UPDATE...
ISSUED AT 558 PM MDT MON SEP 1 2014
UPDATED TO PULL POPS ACROSS THE PLAINS THIS EVENING BASED ON
RADAR AND RECENT HI-RES MODEL DATA. MOISTURE AND LOW CLOUDS
MAY BE POSSIBLE OVER THE FAR SOUTHEAST PLAINS LATE TONIGHT INTO
TUESDAY MORNING...BUT NO PRECIP IS EXPECTED AT THIS TIME. MOZLEY
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 240 PM MDT MON SEP 1 2014
MAIN NEAR/SHORT-TERM METEOROLOGICAL ISSUES ARE
TEMPERATURES...LOCALIZED GUSTY WINDS AT TIMES AND LOCALIZED LOW-
GRADE POPS.
CWFA EXPERIENCING NEAR SEASONAL SEPTEMBER AFTERNOON TEMPERATURES IN
COMBINATION WITH GENERALLY SUNNY SKIES...ALTHOUGH SOME VARIABLE
CLOUDS NOTED OVER PRIMARILY HIGHER TERRAIN LOCATIONS.
IN ADDITION...WIND GUSTS EXCEEDING 30 MPH AT TIMES HAVE BEEN
OBSERVED OVER THE MOUNTAINS OF CHAFFEE COUNTY. RECENT RADAR RETURNS
INDICATE SHOWERS AND THUNDERSTORMS NEARING FAR NORTHEASTERN
COLORADO...WELL NORTH OF OUR CWFA.
LATEST COMPUTER SIMULATIONS...REAL-TIME DATA AND FORECAST MODEL
SOUNDINGS INDICATE THAT GENERALLY DRY CONDITIONS SHOULD CONTINUE
OVER THE MAJORITY OF THE FORECAST DISTRICT FROM LATE THIS AFTERNOON
INTO TUESDAY AFTERNOON...ALTHOUGH RECENT HRRR MODEL DATA SUGGESTS
THAT SHOWERS AND THUNDERSTORMS MAY THREATEN PORTIONS OF NORTHERN EL
PASO AND KIOWA COUNTIES AS WELL AS SECTIONS OF LAS ANIMAS AND BACA
COUNTIES FROM LATER THIS AFTERNOON INTO THIS EVENING.
FOR TUESDAY...THE HIGHEST PROBABILITY OF ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY SHOULD BE NOTED OVER WESTERN HIGHER TERRAIN
LOCATIONS...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS.
GUSTY...PRIMARILY HIGHER TERRAIN WINDS ARE ALSO ANTICIPATED AT TIMES
FROM LATER THIS AFTERNOON INTO TUESDAY WHILE ABOVE SEASONAL EARLY
SEPTEMBER AFTERNOON TEMPERATURES ARE PROJECTED TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 240 PM MDT MON SEP 1 2014
...HOT WITH LOW THUNDERSTORM CHANCES THROUGH EARLY THURSDAY THEN
COOLER WITH INCREASING THUNDERSTORM CHANCES...
TUESDAY EVENING INTO EARLY THURSDAY...THE AIR MASS OVER THE REGION
WILL BE QUITE WARM AND THE THUNDERSTORM CHANCES WILL BE LOW. COULD
BE SOME SPOTTY DRY THUNDERSTORMS AROUND TUESDAY EVENING...MAINLY
OVER THE MOUNTAINS. THEN...WEDNESDAY AFTERNOON...COULD BE SOME
SPOTTY DRY LINE ACTIVITY ACROSS THE FAR SOUTHEAST PLAINS. MODELS
HAVE BEEN BACK AND FORTH ON THIS SO CONFIDENCE IS A LITTLE LOW BUT
THE POSSIBILITY REMAINS ALIVE.
ON THURSDAY...THINGS START TO TRANSITION TO A COOLER...WETTER
PATTERN. MODELS HAVE BEEN PRETTY CONSISTENT ON THIS SO CONFIDENCE
IS INCREASING. IT STARTS WITH THE ARRIVAL OF A COLD FRONT THROUGH
THE EASTERN PLAINS THURSDAY AFTERNOON. THE FRONT PUSHES INTO THE
REGION AS THE RESULT OF AN UPPER DISTURBANCE MOVING THROUGH THE
NORTHERN ROCKIES AND PLAINS. AS THE FRONT MOVES IN...MOIST UPSLOPE
WINDS BEHIND THE FRONT GRADUALLY FIRE THUNDERSTORMS OVER AND NEAR
THE MOUNTAINS IN THE AFTERNOON...SOME OF WHICH WORK EAST ACROSS THE
PLAINS BY LATE IN THE DAY. WITH ADDED MOISTURE IN THE AIR AND
UPSLOPE WINDS...THE THREAT FOR STRONG STORMS WILL INCREASE THIS DAY.
FRIDAY THROUGH MONDAY...WE COULD BE DEALING WITH SOME RICH
SUBTROPICAL MOISTURE AT TIMES...JUST DEPENDING ON HOW THINGS TRACK
OVER THE NEXT FEW DAYS. RIGHT NOW...INDICATIONS ARE THAT FRIDAY AND
SATURDAY COULD BOTH BE PRETTY WET OVER THE REGION WITH CONCERNS OF
FLASH FLOODING. SUNDAY AND MONDAY STILL LOOK PRETTY WET FOR THE
MOUNTAINS...BUT THE PLAINS LOOK MORE STABLE WITH LESS ACTIVITY. ALL
OF THIS IS STILL SEVERAL DAYS AWAY AND HIGHLY SUBJECT TO
CHANGE...HOWEVER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1108 PM MDT MON SEP 1 2014
VFR CONDITIONS AT ALL THREE TERMINALS THROUGH THE NEXT 24 HOURS.
WINDS WILL BE DIURNALLY DRIVEN AND SHOULD REMAIN IN THE 10-15 KT
RANGE ON TUESDAY AFTERNOON ACROSS THE REGION. AN ISOLATED
THUNDERSTORM IS POSSIBLE ALONG THE CONTINENTAL DIVIDE TUESDAY
AFTERNOON WITH A VERY LOW PROBABILITY OF IMPACT AT KALS. MOZLEY
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MOZLEY
SHORT TERM...77
LONG TERM...LW
AVIATION...MOZLEY
AREA FORECAST DISCUSSION
NWS ALBANY NY
843 AM EDT TUE SEP 2 2014
.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL SUPPLY THE REGION WITH ANOTHER DAY OF A
SOUTHWEST FLOW WHICH WILL BRING VERY WARM TEMPERATURES ONCE MORE. A
COLD FRONT WILL APPROACH THE REGION LATE TODAY INTO THE EVENING
BRINGING SHOWERS AND THUNDERSTORMS...SOME OF WHICH COULD CONTAIN
HEAVY RAINFALL AND GUSTY WINDS. SLIGHTLY COOLER AND NOTICEABLY DRIER
AIR WILL FOLLOW ON WEDNESDAY. THE DRY WEATHER IS EXPECTED TO
CONTINUE THE REST OF THE WORK WEEK WITH WARMING TEMPERATURES ONCE
MORE.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 841 AM EDT...QUICK UPDATE TO ACCOUNT FOR ISOLD SHOWERS AHEAD
OF A WEAK SFC TROUGH IN THE WARM SECTOR. SOME SHOWERS ARE ACROSS
THE MOHAWK VALLEY...AND MOVED THROUGH THE CAPITAL REGION...AND THE
BERKSHIRES AND SRN VT. THESE SHOWERS WITH PERHAPS A RUMBLE OF
THUNDER WILL LIMIT THE HEATING THIS MORNING. THE BETTER FORCING
FOR SOME STRONGER THUNDERSTORMS AHEAD OF THE COLD FRONT LOOK LIKE
THEY WILL NOT REACH THE WRN PERIPHERY OF THE FCST AREA UNTIL 22Z-
00Z BASED ON THE LATEST HRRR GUIDANCE. THE FOG WAS ALSO REMOVED
FROM THE GRIDS...AND THE CLOUD COVER WAS INCREASED OVER THE NRN
AND CNTRL THIRD.
THE H500 TEMP THIS MORNING IS -6C WITH KBUF -8C. THE 12Z KALB RAOB
INDICATES A STRONG LOW TO MID LEVEL CAP IS BETWEEN 750-650 HPA
WHICH WILL CURTAIL ANY STRONG TO POSSIBLY SEVERE THREAT UNTIL THE
LATE PM/EARLY EVENING.
OTHERWISE IT WILL BECOME RATHER HOT AGAIN ONCE MORE AS TEMPERATURES
CREST WELL INTO THE 80S. IN THE MID HUDSON VALLEY AND LOWER
LITCHFIELD COUNTY AMBIENT TEMPERATURES COULD TOUCH 90. COMBINE THAT
WITH DEWPOINTS AROUND 70...AND THE APPARENT TEMPERATURES WILL REACH
THE MID AND UPPER 90S...SHORT OF ADVISORY CRITERIA. HILLTOWNS
WILL HAVE APPARENT TEMPERATURES GENERALLY IN THE 85-90 RANGE.
A SOUTH TO SOUTHWEST WIND WILL AVERAGE 5 TO 15 MPH.
A COLD FRONT...CURRENTLY WORKING THROUGH THE OHIO VALLEY...IS
FORECAST TO CROSS OUR REGION LATE THIS AFTERNOON TO THE NORTH AND
WEST OF ALBANY...AND DURING THE EARLY EVENING ALBANY SOUTH AND
EAST.
THE ENTRANCE OF A POTENT UPPER LEVEL JET (NEAR 100 KTS) LOOKS TO
MOVE ACROSS THE REGION THIS EVENING. THE BEST FORCING STILL LOOKS TO
LIFT NORTHWEST OF OUR REGION BUT IT LOOKS CLOSER THAN THIS TIME
YESTERDAY.
THIS JET WILL INCREASE THE DEEP LAYER WIND SHEAR. COMBINE THAT WITH
PRETTY GOOD INSTABILITY (SBCAPES AVERAGING AROUND 1500 J/KG)...AND
IT IS A GOOD BET SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS
AFTERNOON TO OUR WEST AND MOVE NORTHWEST TO SOUTHEAST.
MITIGATING FACTORS INCLUDE A MODEST MID LEVEL LAPSE RATES...ONLY
AROUND 5.5 C/KM. ALSO...THE CAP THAT WAS DISCUSSED EARLY MIGHT
PERSIST INTO THIS EVENING...WHICH COULD CONTINUE TO HINDER
CONVECTION...ALTHOUGH IT IS RATHER WEAK.
IF THUNDERSTORMS DO GET GOING...THEY WILL HAVE A HEALTHY WIND FIELD
TO WORK WITH...WHICH COULD ALLOW FOR BOWING SEGMENTS AND PERHAPS A
SQUALL LINE TO DEVELOP. THESE COULD PRODUCE STRONG TO DAMAGING WIND
GUSTS. SPC CONTINUES TO ONLY HIGHLIGHT THE SOUTHWESTERN PORTION OF
THE MOHAWK VALLEY IN "SLIGHT RISK" FOR SEVERE THUNDERSTORMS. HOWEVER
WE WILL CONTINUE TO USE POSSIBLE GUSTY WINDS AND HEAVY RAINFALL
EVERYWHERE ACROSS OUR REGION.
BY FAR...THE BIGGEST THREAT TODAY WOULD BE DAMAGING WIND...AND WITH
ONLY A VERY SMALL CHANCE FOR LARGE HAIL IN THE BIGGEST UPDRAFTS.
THUNDERSTORM ACTIVITY WILL PERSIST INTO THE EVENING HOURS...BUT AS
THE COLD FRONT MOVES BY...LINGERING SHOWERS AND WEAKENING
THUNDERSTORMS SHOULD DISSIPATE BY AROUND MIDNIGHT.
A SLIGHTLY COOLER AND DRIER AIR MASS WILL MOVE IN
OVERNIGHT...LOWERING TEMPERATURES FROM THE MID 50S NORTHWEST OF THE
CAPITAL REGION...TO THE LOWER TO MID 60S ALBANY SOUTHWARD.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
WEDNESDAY WILL FEATURE A GOOD DEAL OF SUNSHINE...A NORTHWEST BREEZE
10-15 MPH AND HIGH TEMPERATURES 80-85 IN THE VALLEYS (WARMEST NEAR
POUGHKEEPSIE) MID TO UPPER 70S OVER THE HIGHER TERRAIN. DEWPOINTS
WILL DROP INTO THE 50S.
WEDNESDAY NIGHT AS HIGH PRESSURE MOVES OVERHEAD...AND THE SKY IS
EXPECTED TO CLEAR...TEMPERATURES WILL DIP INTO THE 50S REGION WIDE
WITH MID TO UPPER 40S ACROSS THE ADIRONDACKS AND PORTIONS OF THE
SOUTHERN GREENS. IT LOOKS AS IF SOME PATCHY FOG SHOULD FORM
OVERNIGHT.
THURSDAY...HIGH PRESSURE WILL BEGIN TO DRIFT OFFSHORE...ALLOWING A
SOUTHERLY FLOW TO BEGIN TO PUMP WARMER AND SLIGHTLY MORE HUMID AIR
BACK INTO THE REGION. HIGHS WILL REACH AROUND 80 OVER THE HIGHER
TERRAIN...CLOSER TO 85 IN THE VALLEYS. DEWPOINTS WILL BE AROUND
60.
THURSDAY NIGHT WILL BE MILD WITH LOWS RANGING FROM THE UPPER 50S IN
OUTLYING AREAS...60S MOST OTHER PLACES...LOCALLY UPPER 60S IN THE
CAPITAL REGION.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE LARGE AND WARM HIGH PRESSURE SYSTEM WILL HOLD OVER THE REGION
FOR MOST OF FRIDAY WITH SLOWLY INCREASING CLOUDS EXPECTED AND HIGHS
IN THE 80S AS 850 MB TEMPS REACH +16 TO +18 DEG CELSIUS. LATE IN THE
DAY THERE IS A CHANCE OF SHOWERS OR TSTMS ACROSS THE NORTHWEST PART
OF THE FORECAST AREA AS A COLD FRONT AND UPPER LEVEL TROF APPROACH
FROM THE WEST.
FRI NIGHT INTO SATURDAY...MOST ACTIVE PORTION OF THE LONG TERM WITH
A COLD FRONT INTERACTING WITH A MOIST AND UNSTABLE AIR MASS. MODEL
TIMING OF THE BOUNDARY IS STILL VARIABLE...BUT THE MODELS ARE CLOSER
THAN THEY WERE 24 HOURS AGO. ALL THE MEDIUM RANGE MODELS NOW AGREE
THAT ANY SHOWERS ASSOCIATED WITH THIS FRONTAL BOUNDARY WILL BE OUT
OF THE REGION BEFORE SUNDAY...WITH SOME MODELS MUCH SOONER. WILL
CONTINUE TO KEEP CHANCE POPS ACROSS THE REGION FRIDAY NIGHT AND
SATURDAY...THEN LOWER POPS TO ONLY SLIGHT CHANCE BY LATE SATURDAY
NIGHT. LOWS FRIDAY NIGHT WILL BE IN THE UPPER 50S AND 60S. HIGHS
SATURDAY IN THE UPPER 60S ACROSS THE ADIRONDACKS...AND THE 70S TO
LOWER 80S ELSEWHERE. LOWS SATURDAY NIGHT IN THE UPPER 40S AND 50S AS
THE COOLER AIR BEHIND THE FRONT BEGINS TO SEEP IN.
ON SUNDAY A SPRAWLING HIGH PRESSURE SYSTEM WILL BUILD INTO THE
REGION AND CONTROL OUR WEATHER INTO EARLY NEXT WEEK. THIS HIGH
PRESSURE AREA IS OF CANADIAN ORIGIN SO IT WILL BE NOTICEABLY COOLER
SUNDAY AND MONDAY. HIGHS SUNDAY AND MONDAY WILL BE IN THE MID 60S TO
MID 70S. LOWS SUNDAY NIGHT IN THE MID 40S TO MID 50S.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
ANY LEFTOVER FOG/STRATUS AT KGFL/KPSF WILL BE GONE BY 13Z...
OTHERWISE THE TAF SITES WILL FEATURE VFR CONDITIONS UNTIL A
SHORTWAVE TROF AND COLD FRONT APPROACH FROM THE WEST LATE IN THE DAY
AND MOVE THROUGH THE TAF SITES THIS EVENING. SOME ISOLD SHOWERS
ASSOCIATED WITH A PREFRONTAL SFC TROUGH MAY GET CLOSE TO
TERMINALS...AND A VCSH GROUP WAS USED AT KALB BTWN 12Z-16Z.
BEGINNING 21Z TO 23Z HAVE FORECASTED A 4-6 HOUR WINDOW OF PROB30 FOR
MVFR CONDITIONS DUE TO THUNDERSTORMS AT ALL THE TAF SITES. THE
THREAT FOR TSTMS WILL END WHEN THE COLD FRONT MOVES THROUGH
BETWEEN 02Z AND 04Z TUESDAY NIGHT.
SURFACE WINDS WILL BECOME SOUTH OR SOUTHWEST AT 5 TO 10 KTS TODAY
INTO THIS EVENING...THEN SHIFT TO WESTERLY BEHIND THE COLD FRONT AT
4 TO 8 KTS.
OUTLOOK...
WEDNESDAY TO FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY NIGHT TO SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA...TSRA.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL MOVE EAST OF OUR REGION TODAY ALLOWING A COLD
FRONT TO MOVE IN LATE TODAY INTO THIS EVENING. THIS FRONT WILL BRING
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE AREA...MAINLY LATE
THIS AFTERNOON INTO THE EARLY EVENING HOURS.
IT WILL BE A RATHER HOT DAY WITH PARTIAL SUNSHINE BEFORE THE SHOWERS
AND STORMS ARRIVE. RH VALUES WILL ONLY DROP TO THE 55-65 PERCENT
RANGE THIS AFTERNOON. A SOUTH TO SOUTHWEST WIND WILL AVERAGE 5-15
MPH.
RAINFALL FROM THE THUNDERSTORMS LOOK REACH AROUND A QUARTER INCH OR
BETTER IN MOST AREAS FROM ALBANY NORTHWARD...A QUARTER INCH OR LESS
SOUTH OF ALBANY. HOWEVER...ANY THUNDERSTORM COULD PRODUCE HEAVY
RAINFALL PRODUCING LOCALIZED AMOUNTS EASILY EXCEEDING AN INCH IN ANY
GIVEN SPOT.
RH VALUES TONIGHT WILL BE IN THE TYPICAL 80-100 PERCENT RANGE
ALTHOUGH A BIT OF BREEZE MIGHT PERSIST IN MANY AREAS...AS THE WIND
SHIFTS FROM SOUTHWEST TO NORTHWEST.
WEDNESDAY WILL FEATURE LOWER HUMIDITY ALONG WITH A GOOD DEAL OF
SUNSHINE. A NORTHWEST BREEZE WILL AVERAGE 10-15 MPH WITH SOME HIGHER
GUSTS INTO THE 20S...MAINLY OVER THE HIGHER TERRAIN/MOHAWK VALLEY
AND GREATER CAPITAL REGION. AFTERNOON RH VALUES WILL DROP INTO THE
35-45 PERCENT RANGE.
A FULL RECOVERY WEDNESDAY NIGHT WITH THE WIND GOING CALM...AND RH
VALUES NEAR 100 PERCENT WITH PLENTY OF DEW EXPECTED.
THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE LATE FRIDAY
INTO SATURDAY.
&&
.HYDROLOGY...
IT WILL BE MAINLY DRY THROUGH MIDDAY. THEN...SHOWER AND THUNDERSTORM
COVERAGE SHOULD INCREASE FROM NORTHWEST TO SOUTHEAST THROUGH THE
AFTERNOON INTO THE EARLY EVENING. AVERAGE BASIN RAINFALL WITH THESE
STORMS IS PROJECTED TO BE AROUND HALF AN INCH ACROSS NORTHERN AREAS
OF OUR HYDROLOGICAL SERVICE AREA (HSA)...NORTH OF ALBANY. LOOK FOR
AROUND HALF AN INCH IN AND AROUND THE CAPITAL REGION...AND LESSER
AMOUNTS OF A QUARTER INCH OR LESS FURTHER SOUTH.
PWATS ARE EXPECTED TO EXCEED TWO INCHES TODAY. THIS WILL ALLOW FOR
THE POTENTIAL FOR ANY THUNDERSTORM TO PRODUCE LOCALLY MUCH HEAVY
RAINFALL...POSSIBLY EXCEEDING AN INCH AND THIS RAIN COULD FALL IN A
SHORT TIME. THEREFORE THERE IS THE POTENTIAL FOR SIGNIFICANT PONDING
OF WATER ON ROADWAYS AND AREAS OF POOR DRAINAGE. WHILE THE THREAT
FOR ANY ORGANIZED FLASH FLOODING IS VERY LOW...A HIGH LOCALIZED
FLASH FLOOD CANNOT BE RULED OUT.
DRIER WEATHER RETURNS BY WEDNESDAY...LASTING THROUGH THE REMAINDER
OF THE WORKWEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV/WASULA
NEAR TERM...HWJIV/WASULA
SHORT TERM...HWJIV
LONG TERM...GJM
AVIATION...GJM/WASULA
FIRE WEATHER...HWJIV/NAS
HYDROLOGY...HWJIV/NAS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
332 PM EDT TUE SEP 2 2014
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT. HIGH PRESSURE WILL BUILD
INTO THE AREA FROM THE WEST AND PERSIST THROUGH FRIDAY. ANOTHER COLD
FRONT WILL CROSS THE REGION ON SATURDAY AND THEN STALL TO THE SOUTH
OF OUR AREA. HIGH PRESSURE WILL BUILD ACROSS THE GREAT LAKES REGION
AND THEN SLIDE ACROSS TO THE NORTH OF THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
FRONT IS JUST NOW MOVING OFF THE GREAT LAKES INTO FAR WESTERN PA. DO
NOT EXPECT IT TO MAKE ITS ARRIVAL MUCH BEFORE 06Z. HIGH RES MODELS
LIKE THE HRRR HAVE BEEN CONSISTENT IN SHOWING A LINE OF CONVECTION
MOVING IN AHEAD OF THE FRONT LATE THIS EVENING. HOWEVER, BY THAT
TIME, INSTABILITY SHOULD BE WANING AND THERE COULD BE A SMALL
BOUNDARY LAYER INVERSION. THUS, THE LINE SHOULD BE DISSIPATING AS IT
MOVES THROUGH THE REGION. PWATS ARE STILL WELL ABOVE NORMAL, SO
LOCALIZED HEAVY RAIN WILL BE POSSIBLE. WHILE THE HIGHEST SHEAR
VALUES SHOULD REMAIN NW OF OUR REGION, COULD SEE A FEW STRONG WINDS
GUSTS WHEN THE FRONT INITIALLY ARRIVES IN SOUTHEAST PA BUT THAT
THREAT SHOULD BE SHORT LIVED AS WE TRANSITION FROM SURFACE BASED TO
ELEVATED INSTABILITY.
GIVEN THE VERY LATE ARRIVAL OF THE COLD FRONT, AND THE FACT THAT THE
TEMPERATURE GRADIENT ACROSS THE FRONT IS RATHER SMALL, MINS TONIGHT
SHOULD NOT BE TOO MUCH LOWER THAN THEY WERE THIS MORNING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
AS MENTIONED PREVIOUSLY, THERE WON`T BE A LARGE DIFFERENCE IN THE
TEMPERATURES POST FRONTAL (HIGHS WILL GENERALLY BE IN THE 80S ACROSS
THE REGION). HOWEVER, WHAT THE FRONT WILL BE BRINGING IS CONSIDERABLE DRY
AIR ADVECTION. DEW POINTS INTO THE UPPER 50S AND LOWER 60S ACROSS
THE REGION BY TOMORROW AFTERNOON. THUS, WHILE HEAT INDEX VALUES HAVE
BEEN ABOUT 5 DEGREES ABOVE AIR TEMPERATURE TODAY, BY TOMORROW, HEAT
INDEX VALUES WILL BE RIGHT AT THE AIR TEMPERATURES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
WEDNESDAY NIGHT THROUGH FRIDAY...HIGH PRESSURE DOMINATES OUR WEATHER
THROUGH THE END OF THE WEEK AS IT SHIFTS JUST TO TOUR SOUTH AND EAST
LATE WEDNESDAY THROUGH FRIDAY. THIS WILL KEEP US IN A MORE SOUTH TO
SOUTHWESTERLY FLOW AND IN RETURN WE WILL CONTINUE TO SEE AN INCREASE
IN MOISTURE ACROSS THE REGION. TEMPERATURES WILL CONTINUE TO MIMIC
MORE OF MID SUMMER AS OPPOSED TO LATE SUMMER AND WE WILL SEE MAX
TEMPS REACH INTO THE UPPER 80S TO AROUND 90 ON BOTH THURSDAY AND
FRIDAY.
SATURDAY...THE HIGH SHIFTS FURTHER OFFSHORE AND WE WILL BE AWAITING
THE PASSAGE OF A COLD FRONT THROUGH THE DAY. THE FRONT APPEARS TO BE
SLOW MOVING AND MAY TAKE ALL DAY TO CROSS FROM THE NORTHWESTERN
PORTIONS OF THE AREA AND THEN THROUGH THE SOUTHERN MOST POINTS. WE
WILL LIKELY SEE A PRE-FRONTAL TROUGH DEVELOP ACROSS THE AREA AND
THIS WILL LIKELY HELP SERVE AS A FOCUS FOR ANY PRE-FRONTAL
CONVECTION AND SHOWERS. SATURDAY WILL BE THE LAST DAY OF THIS HEAT
WAVE AS COOLER AIR BEHIND THE FRONT WILL DROP TEMPS QUITE A BIT.
SUNDAY...THE FRONT IS SLOW ENOUGH THAT WE MAY NOT SEE IT CLEAR THE
DELMARVA AREA UNTIL SUNDAY MORNING. AS THE FRONT PUSHES SOUTH, THE
QUESTION WILL BE, WHERE WILL THE FRONT STALL? CURRENT MODEL GUIDANCE
INDICATES THAT THE FRONT WILL HAVE ENOUGH OF A PUSH TO GET SOUTH OF
OUR AREA, WHICH SHOULD ALLOW FOR SOME COOLER AND DRIER AIR TO
INFILTRATE OUR REGION. THE SLOW NATURE OF THE FRONT WILL ALLOW FOR
SHOWERS TO CONTINUE, ESPECIALLY FURTHER SOUTH, INTO SUNDAY. AS THE
FRONT PUSHES FURTHER SOUTH, ANY LINGERING SHOWERS SHOULD END FROM
NORTH TO SOUTH. WITH HIGH PRESSURE BUILDING INTO THE GREAT LAKES
AREA AND THE STALLED BOUNDARY TO OUR SOUTH, WE WILL BE IN A MORE
EASTERLY FLOW REGIME WITH MOSTLY CLOUDY SKIES. THIS WILL ALLOW US TO
BE COOLER ACROSS THE AREA. TEMPERATURES WILL ONLY MAKE IT INTO THE
70S THROUGH THE REGION AND IT WILL TRULY FEEL LIKE FALL OUT THERE.
MONDAY THROUGH TUESDAY...THE BOUNDARY REMAINS STALLED TO OUR SOUTH
BUT AS WE HEAD INTO MONDAY, A WAVE DEVELOPS ALONG IT AND IT STARTS
TO MOVE A BIT. IT CURRENTLY LOOKS LIKE THE WAVE HELPS MOVE THE
FRONT SLIGHTLY NORTH AND THEN TO THE EAST, KEEPING THE MAIN
BOUNDARY TO OUR SOUTH. COOLER TEMPERATURES WILL CONTINUE ON MONDAY
AND TUESDAY WITH HIGHS INTO THE MID TO UPPER 70S, WITH SOME LOWER
80S POSSIBLE AS SKIES CLEAR OUT AND WE START TO SEE MORE SUNSHINE.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
ISOLATED TSRA WILL BE POSSIBLE THROUGH 00Z THIS EVENING.
HOWEVER, THINK THE BULK OF THE THUNDERSTORM ACTIVITY SHOULD REMAIN
WEST OF THE REGION. THE COVERAGE THROUGH THIS TIME IS TOO LIMITED
TO MENTION IN MOST OF THE TAFS FOR NOW. STARTING AROUND 00Z, WE
SHOULD SEE A LINE OF SHRA AND TSRA MOVE INTO THE REGION FROM THE
WEST. HIGH RESOLUTION MODELS HAVE BEEN CONSISTENT IN SHOWING THIS
GENERAL PATTERN AND TIMING. HOWEVER, THERE IS SOME QUESTION OF THE
SOUTHERN EXTENT OF THE LINE (WHICH MAY NOT GO SOUTH OF PHL), AND IF
THE LINE WILL START TO SCT BEFORE IT REACHES THE DELAWARE RIVER
VALLEY. THEREFORE HAVE INCLUDED A TEMPO FOR THE SE PA SITES (KRDG
AND KABE) AND KTTN WHERE THERE IS HIGHER CONFIDENCE, BUT ONLY HAVE
MENTION OF VCSH FOR MOST OF THE REST OF THE SITES.
ONCE THE FRONT MOVES THROUGH AFTER 06Z, EXPECT NORTHWESTERLY WINDS
AND GENERALLY VFR CONDITIONS. THERE IS A SMALL RISK OF BR
DEVELOPMENT BUT WITH DRY AIR ADVECTION BEHIND THE FRONT, THINK THIS
IS UNLIKELY.
OUTLOOK...
WEDNESDAY NIGHT THROUGH FRIDAY... MAINLY VFR CONDITIONS EXPECTED.
SOME FOG IS POSSIBLE WHICH MAY CAUSE MVFR/IFR CONDITIONS ON THU
AND FRI MORNINGS.
SATURDAY THROUGH SUNDAY...MAINLY VFR CONDITIONS EXPECTED WITH
MVFR/IFR CONDITIONS POSSIBLE IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
THROUGH TOMORROW. GUSTY WINDS WILL BE POSSIBLE IN THE VICINITY OF
ANY THUNDERSTORMS THIS AFTERNOON AND TONIGHT. AN ABRUPT WIND SHIFT
TO NORTHWESTERLY WINDS IS EXPECTED WITH A COLD FRONT THAT WILL MOVE
THROUGH LATE TONIGHT. HOWEVER, WIND GUSTS SHOULD REMAIN WELL BELOW
20KT EVEN WITH THE FRONT.
OUTLOOK...
WEDNESDAY NIGHT THROUGH SUNDAY...SUB-ADVISORY CONDITIONS ARE
EXPECTED. SOME STRONGER GUSTS AND HIGHER WAVES ARE POSSIBLE IN
SHOWERS AND THUNDERSTORMS, MAINLY IN THE SATURDAY/SUNDAY TIMEFRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...JOHNSON
SHORT TERM...JOHNSON
LONG TERM...MEOLA
AVIATION...JOHNSON/MEOLA
MARINE...JOHNSON/MEOLA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
400 PM EDT TUE SEP 2 2014
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE MAIN NORTHERN STREAM
FLOW FAR TO OUR NORTH ALONG THE CANADIAN BORDER AND OVER TOP AN
ELONGATED WEST TO EAST ORIENTED UPPER RIDGE EXTENDING ACROSS THE
SOUTHERN TIER OF THE CONUS. OUR FORECAST AREA RESIDES UNDER THIS
LARGE UPPER RIDGE...HOWEVER A TUTT FEATURE RETROGRADING WESTWARD
OVER THE BAHAMAS IS BEGINNING TO ERODE THE RIDGE TO OUR SOUTH
AND EAST...AND WILL BEGIN TO BREAK DOWN THE RIDGE OVER OUR HEADS
TONIGHT.
02/12Z SOUNDING PROFILE SHOWS THE INFLUENCE OF THE UPPER RIDGE
OVERHEAD WITH A SUBSIDENCE INVERSION SIGNATURE AROUND 750MB. ABOVE
THIS LAYER IT ON THE DRY SIDE. THE RESULTING PW IS LOW AROUND
1.7"...WHICH IS BELOW AVERAGE FOR EARLY SEPTEMBER...BUT NOT AN
EXTREME VALUE. WE HAVE SEEN A BIT OF COOLING IN THE MID-LEVELS SINCE
MONDAY...POSSIBLY THE VERY BEGINNING INFLUENCE OF THE APPROACHING
TUTT. WILL EXPECT TO SEE ANOTHER DEGREE OR 2 OF COOLING IN THE
MID-LEVELS OVER THE NEXT 24 HOURS AS THE TUTT PASSES JUST TO OUR
SOUTH. THIS COOLING ALONG WITH OUR EVENTUAL POSITION ON THE EASTERN
PERIPHERY OF THE TUTT (FAVORED FOR UPWARD MOTION AND CONVECTION) MAY
LEAD TO ENHANCED CONVECTION LATER IN THE WEEK.
SEA-BREEZE HAS MOVED INLAND TO AROUND I-75 FROM TAMPA BAY SOUTHWARD
PER OBS AND RADAR ANALYSIS...BUT APPEARS TO BE PINNED VERY NEAR THE
COAST UP ALONG THE NATURE COAST. THE 10 KNOTS OF EASTERLY FLOW JUST
ABOVE THE SURFACE WILL KEEP THE INLAND PENETRATION SLOW THE NEXT FEW
HOURS BEFORE THE EAST COAST SEA-BREEZE / CONVECTIVE OUTFLOWS COLLIDE
WITH IT DURING THE EARLY EVENING. HAVE SEEN SOME SCT STORMS ALREADY
FORM OVER THIS BOUNDARY AND DRIFT WESTWARD INTO THE POST SEA-BREEZE
ENVIRONMENT. THIS IS UNLIKE YESTERDAY WHEN VERY LITTLE OCCURRED
UNTIL THE MAIN COLLISION AND ALLOWED THE RELEASE OF ALL THE DAYS
INSTABILITY. THEREFORE...THE POTENTIAL FOR EXPLOSIVE THUNDERSTORMS
DEVELOPMENT THIS EVENING IS LOWER...BUT WILL STILL NEED TO BE
WATCHED CLOSELY. ACROSS THE FAR SOUTHERN ZONES THE SHOWERS AND
STORMS ARE FILLING IN AND RAIN CHANCES LOOKING QUITE LIKELY TO THE
SOUTH OF SARASOTA OVER THE NEXT SEVERAL HOURS.
STORM MOTION WILL BE WESTWARD AFTER INITIATION...SO MARINERS SHOULD
CONTINUE TO BE AWARE OF THE WEATHER OVER LAND TO THEIR EAST AND BE
PREPARED FOR STORMS TO RAPIDLY DEVELOP AND MOVE OFFSHORE.
&&
.SHORT TERM (TONIGHT AND WEDNESDAY)...
TONIGHT...
THE ACTIVITY WILL ALL PUSH OFFSHORE WITHIN A COUPLE HOURS OF SUNSET
AND PROVIDE THE REGION WITH A MOSTLY DRY AND SEASONABLE OVERNIGHT
PERIOD. CAN NOT RULE OUT A FEW ISOLATED SHOWERS LATER TONIGHT
ROTATING IN FROM THE EAST OVER CHARLOTTE/LEE COUNTY AS THE INFLUENCE
OF THE TUTT INCREASES...BUT IMPACT SHOULD BE MINIMAL AND WILL LEAVE
MENTION OUT OF THE FORECAST FOR NOW.
WEDNESDAY...
TUTT CELL MOVES OVER THE FLORIDA STRAITS AND SOUTH FLORIDA ENDING
THE DOMINATION OF THE UPPER RIDGE ON THE FLORIDA PENINSULA. AT THE
LOWER LEVELS THOUGH...WILL STILL BE DEALING WITH A LIGHT/MODERATE
EASTERLY FLOW REGIME. THE MORNING HOURS WILL BE GENERALLY QUIET AND
DRY IN TERMS OF WEATHER...BUT WE ARE LIKELY TO SEE CONVECTIVE
INITIATION A BIT EARLIER THAN HAS BEEN THE CASE OVER RECENT DAYS AS
THE LOSS OF LARGE SCALE SUBSIDENCE WILL PROMOTE A LOWER CONVECTIVE
TEMPERATURE. WITH THE EARLIER INITIATION...THE PATTERN OF CONVECTION
BECOME LESS EASY TO PUT DETAIL INTO AS THERE IS MORE TIME FOR
NUMEROUS OUTFLOW BOUNDARIES TO DISRUPT THE LARGE SCALE FLOW.
THEREFORE WILL KEEP HIGH END CHANCE 40-55% RAIN CHANCES IN AT MOST
LOCATIONS...BUT WITH THE EASTERLY FLOW REGIME...WILL KEEP A TENDENCY
FOR THE HIGHER RAIN CHANCES TO MIGRATE TOWARD THE WEST COAST WITH
TIME DURING THE AFTERNOON AND EARLY EVENING.
&&
.LONG TERM (WEDNESDAY NIGHT-TUESDAY)...
MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH THE
LONG TERM PERIODS. AN UPPER LEVEL TROUGH AND INCREASING DEEP
LAYER MOISTURE WILL SPREAD NORTHWESTWARD ACROSS THE STATE ON
THURSDAY AND FRIDAY...WITH WEAK UPPER LEVEL RIDGING THEN BUILDING
INTO THE AREA OVER THE WEEKEND AND INTO EARLY NEXT WEEK. AT THE
SURFACE...THE SUBTROPICAL RIDGE AXIS IS EXPECTED TO REMAIN NORTH
OF THE FORECAST AREA THROUGH THE END OF THE WORK WEEK...WITH MODEL
SOLUTIONS THEN SHOWING SOME DISAGREEMENT IN POSITIONING DETAILS
OVER THE WEEKEND AND INTO EARLY NEXT WEEK. THE GFS AND CANADIAN
SHOW THE RIDGE AXIS REMAINING NORTH OF THE FORECAST AREA...BUT THE
ECMWF SHOWS IT SHIFTING SOUTHWARD INTO CENTRAL FLORIDA.
OVERALL...TYPICAL SUMMERTIME WEATHER IS EXPECTED TO PREVAIL WITH
SCATTERED TO NUMEROUS MAINLY AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS EXPECTED EACH DAY. HIGH TEMPERATURES WILL REMAIN CLOSE
TO NORMAL THROUGH THE LONG TERM PERIOD.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS THE REGION LATE THIS MORNING.
BEGINNING TO SEE THE FIRST OF A CU FIELD BEGIN TO DEVELOP. SCT
SHOWERS AND STORMS WILL BE MOVING EAST TO WEST ACROSS THE PENINSULA
DURING THE AFTERNOON. KFMY/KRSW/KPGD WILL BE FIRST TO SEE THE STORMS
IN THE VICINITY BY MID AFTERNOON. FURTHER NORTH AROUND THE TAMPA BAY
TERMINALS STORMS ARE LIKELY TO BE LATER IN THE AFTERNOON AND EVENING
HOURS. AWAY FROM ANY STORMS...VFR CONDITIONS WILL PREVAIL THROUGH
THE TAF PERIOD.
&&
.MARINE...
EAST SOUTHEAST WINDS LESS THAN 15 KNOTS AND SEAS 2 FEET OF LESS
WILL CONTINUE INTO NEXT WEEK AS HIGH PRESSURE OVER THE ATLANTIC
PUSHES WEST OVER THE FLORIDA PENINSULA. THE SEA BREEZE WILL SET UP
ALONG AND NEAR THE COAST EACH DAY ALLOWING FOR AN ONSHORE FLOW FROM
THE SOUTHWEST TO NORTHWEST DIRECTION. SCATTERED SHOWERS AND STORMS
WILL BE POSSIBLE EACH DAY DEVELOPING OVER LAND AND THEN PUSHING
WESTWARD OVER THE COASTAL WATERS DURING THE EVENING HOURS. THE ONLY
EXPECTED HAZARD WILL BE GUSTY WINDS AND HIGHER SEAS IN THE VICINITY
OF THUNDERSTORMS.
&&
.FIRE WEATHER...
A RIDGE OF HIGH PRESSURE WILL REMAIN NORTH OF THE REGION FOR THE
NEXT SEVERAL DAYS. THIS WILL RESULT IN EASTERLY WINDS WITH THE
HIGHEST RAIN CHANCES ALONG THE I-75 EACH AFTERNOON. OTHER THAN THE
DAILY STORMS...NO SIGNIFICANT FIRE WEATHER CONCERNS ARE EXPECTED.
FOG POTENTIAL...PATCHY GROUND FOG COULD DEVELOP LATE EACH
NIGHT...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN DURING THE
PREVIOUS EVENING. HOWEVER...NO SIGNIFICANT FOG IS ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 76 90 76 91 / 30 50 30 60
FMY 75 92 74 91 / 10 50 10 60
GIF 74 92 74 92 / 10 50 10 50
SRQ 74 92 73 91 / 30 40 30 60
BKV 71 91 71 92 / 20 50 30 60
SPG 79 91 78 90 / 30 40 30 60
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/FIRE WX...MROCZKA
MARINE...MCKAUGHAN
LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1130 AM EDT TUE SEP 2 2014
.UPDATE (REST OF TODAY AND TONIGHT)...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE MAIN NORTHERN STREAM
FLOW FAR TO OUR NORTH ALONG THE CANADIAN BORDER AND OVER TOP AN
ELONGATED WEST TO EAST ORIENTED UPPER RIDGE EXTENDING ACROSS THE
SOUTHERN TIER OF THE CONUS. OUR FORECAST AREA RESIDES UNDER THIS
LARGE UPPER RIDGE...HOWEVER A TUTT FEATURE RETROGRADING WESTWARD
OVER THE BAHAMAS IS BEGINNING TO ERODE THE RIDGE TO OUR SOUTH
AND EAST...AND WILL BEGIN TO BREAK DOWN THE RIDGE OVER OUR HEADS
TONIGHT.
02/12Z SOUNDING PROFILE SHOWS THE INFLUENCE OF THE UPPER RIDGE
OVERHEAD WITH A SUBSIDENCE INVERSION SIGNATURE AROUND 750MB. ABOVE
THIS LAYER IT ON THE DRY SIDE. THE RESULTING PW IS LOW AROUND
1.7"...WHICH IS BELOW AVERAGE FOR EARLY SEPTEMBER...BUT NOT AN
EXTREME VALUE. WE HAVE SEEN A BIT OF COOLING IN THE MID-LEVELS SINCE
MONDAY...POSSIBLY THE VERY BEGINNING INFLUENCE OF THE APPROACHING
TUTT. WILL EXPECT TO SEE ANOTHER DEGREE OR 2 OF COOLING IN THE
MID-LEVELS OVER THE NEXT 24 TO 36 HOURS AS THE TUTT PASSES JUST TO
OUR SOUTH. THIS COOLING ALONG WITH OUR EVENTUAL POSITION ON THE
EASTERN PERIPHERY OF THE TUTT (FAVORED FOR UPWARD MOTION AND
CONVECTION) MAY LEAD TO ENHANCED CONVECTION LATER IN THE WEEK.
BACK TO TODAY. SOME MIXED SIGNALS REGARDING CONVECTIVE TIMING AND
EVOLUTION FOR THE AFTERNOON AND EVENING. HIRES CONVECTION ALLOWING
MODELS ARE KIND OF SPLIT...WITH A FEW MEMBERS RATHER ACTIVE ALONG
THE I-75 CORRIDOR LATER TODAY...AND A FEW MEMBERS WHO HAVE TROUBLE
GENERATING MUCH CONVECTION...AND ESPECIALLY DEEP CONVECTION. MORE
THAN LIKELY IT IS DIFFERING WAYS THE GUIDANCE IS HANDLING THE
SUBSIDENCE OF THE UPPER RIDGE RESULTING IN THE DIFFERENCES. AM
TENDING TO SIDE ON THE MORE ACTIVE CONVECTION SOLUTIONS. THE
SUBSIDENCE INVERSION IS THERE...BUT IS NOT REALLY PRONOUNCED. GIVEN
THE WEAKNESS OF THE OVERALL SUBSIDENCE AND THE EASTERLY FLOW BEING
FAVORED FOR ENHANCED CONVERGENCE/UPDRAFTS ALONG THE FLORIDA WEST
COAST WILL KEEP HIGH END CHANCE POPS IN THE FORECAST ALONG THE
ENTIRE I-75 CORRIDOR. SIMILAR TO THE PAST FEW DAYS...THE STORMS ARE
LIKELY TO BREAK OUT FIRST DURING THE EARLY/MID AFTERNOON DOWN TOWARD
FORT MYERS AND OVER THE INTERIOR SOUTH (HIGHLANDS/DESOTO/HARDEE
COUNTIES)...AND THEN MIGRATE/EVOLVE NORTH AND WEST INTO THE TAMPA
BAY AREA AND NATURE COAST DURING THE LATE AFTERNOON/EARLY EVENING.
THE EASTERLY FLOW JUST ABOVE THE SURFACE IS 8-10 KNOTS THIS
AFTERNOON WHICH WILL SLOW THE INLAND PROPAGATION OF THE
SEA-BREEZE...BUT NOT STOP IT. THEREFORE...WOULD EXPECT THE BREEZE TO
BE SET UP NEAR OR JUST INSIDE OF I-75 BY LATE AFTERNOON...AND IT
WILL BE THIS ZONE WHERE STORMS WILL IGNITE AS THE EAST COAST
SEA-BREEZE ARRIVES AND INTERACTS.
STORM MOTION WILL BE WESTWARD AFTER INITIATION...SO MARINERS SHOULD
BE AWARE OF THE WEATHER OVER LAND TO THEIR EAST AND BE PREPARED FOR
STORMS TO RAPIDLY DEVELOP AND MOVE OFFSHORE LATER TODAY. THE
ACTIVITY WILL ALL PUSH OFFSHORE WITHIN A COUPLE HOURS OF SUNSET AND
PROVIDE THE REGION WITH A MOSTLY DRY AND SEASONABLE OVERNIGHT
PERIOD.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS THE REGION LATE THIS MORNING.
BEGINNING TO SEE THE FIRST OF A CU FIELD BEGIN TO DEVELOP. SCT
SHOWERS AND STORMS WILL BE MOVING EAST TO WEST ACROSS THE PENINSULA
DURING THE AFTERNOON. KFMY/KRSW/KPGD WILL BE FIRST TO SEE THE STORMS
IN THE VICINITY BY MID AFTERNOON. FURTHER NORTH AROUND THE TAMPA BAY
TERMINALS STORMS ARE LIKELY TO BE LATER IN THE AFTERNOON AND EVENING
HOURS. AWAY FROM ANY STORMS...VFR CONDITIONS WILL PREVAIL THROUGH
THE TAF PERIOD.
&&
.MARINE...
EAST SOUTHEAST WINDS LESS THAN 15 KNOTS AND SEAS 2 FEET OF LESS
WILL CONTINUE INTO NEXT WEEK AS HIGH PRESSURE OVER THE ATLANTIC
RIDGES WEST OVER THE FLORIDA PENINSULA. THE SEA BREEZE WILL SET UP
ALONG THE COASTLINE EACH DAY TURNING THE WINDS TO AN ONSHORE FLOW
OUT OF THE SOUTHWEST THROUGH NORTHWEST DIRECTION. SCATTERED SHOWERS
AND STORMS WILL BE POSSIBLE EACH DAY DEVELOPING OVER LAND AND THEN
PUSHING WESTWARD OVER THE COASTAL WATERS DURING THE EVENING HOURS.
THE ONLY EXPECTED HAZARD WILL BE GUSTY WINDS AND HIGHER SEAS IN THE
VICINITY OF THUNDERSTORMS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 91 76 91 76 / 50 30 40 30
FMY 93 74 91 74 / 50 10 50 20
GIF 93 74 92 74 / 40 10 40 10
SRQ 92 75 91 73 / 50 30 50 30
BKV 93 72 93 71 / 50 20 40 30
SPG 92 79 90 78 / 50 30 40 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION...MROCZKA
MARINE...WYNN
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
345 AM EDT TUE SEP 2 2014
.CURRENTLY...WEAK HIGH PRES EXISTS OVER EXTREME S GA WITH WEAK
TROUGH NEAR COASTAL GA. DEBRIS CLOUDS CONTINUE TO DISSIPATE AS LATE
NIGHT CONVECTION LINGERED LATE TONIGHT OVER INLAND AREAS. SLOW
DISSIPATION OF CLOUDS WILL ENSURE INLAND TEMPS WILL ONLY STEADILY
DECREASE TOWARD SUNRISE. ALOFT...MID LEVEL HIGH IS LOCATED OVER SRN
GA AS WELL...WITH NEARLY ZONAL FLOW OVER NE FL. SOME PATCHY FOG IS
BEING REPORTED NOW AND INCLUDED IN THE LATEST FCST BY SUNRISE. A FEW
SHOWERS ARE LOCATED AROUND 60 NM OR MORE OFFSHORE AND WILL LIKELY
PUSH A LITTLE FURTHER EWD OVER THE NEXT FEW HRS.
.SHORT TERM...
TODAY...A FAIRLY SIMILAR PATTERN TO YESTERDAY WITH MEAN LAYER HIGH
PRES CONTINUING JUST NW OF THE AREA AND MEAN FLOW FROM THE NE AND E.
MODELS GENERALLY SHOW THE E COAST SEA BREEZE FIRING SOME CONVECTION
BY LATE MORNING AND EARLY AFTN...PERHAPS A BIT EARLIER THAN PRIOR
DAYS. ISOLD TO SCT SHOWERS AND STORMS ARE FCST TO DEVELOP OVER THE
ERN ZONES BY NOON-1PM AND THEN GRADUALLY BLOSSOM AND DRIFT INLAND
AROUND 5 TO 10 MPH. THE HRRR MODEL SHOWS DEEPEST MOISTURE OVER SE GA
AND PORTIONS OF NE FL LATER TODAY AND WILL PLACE HIGH END CHANCE TO
LIKELY POPS IN THESE AREAS...MAINLY AFTER 2 PM. WARM TEMPS AT 850 MB
AROUND 18/19C STILL SUPPORT HIGHS IN THE LOWER TO MID 90S...YIELDING
HEAT INDICES UP TO 105 IN SE GA. PRECIP WILL SLOWLY FADE TONIGHT
WITH SCT COVERAGE INLAND AND MORE ISOLD TOWARD THE COAST. PATCHY FOG
WILL BE POSSIBLE FOR INLAND AREAS LATE IN THE NIGHT...USING
CONSENSUS OF GUIDANCE TOOLS.
WEDNESDAY...SOMEWHAT OF A TRANSITION DAY AS TROPICAL UPPER LEVEL
TROUGH OVER THE FL STRAITS AND BAHAMAS PUSHES WWD WHILE MID LEVEL
HIGH OVER GA LIFTS SLIGHTLY NWD. THIS SCENARIO WILL INCREASE MEAN
ELY WINDS AND ALLOW A QUICKER PUSH OF THE E COAST SEA BREEZE.
INITIALLY HIGH PWATS WILL DECREASE DURING THE LATTER HALF OF THE DAY
ACROSS OUR SERN ZONES AS A DRY SLOT MOVES NWWD OVER CENTRAL FL AND
EVENTUALLY INTO OUR SRN ZONES. OVERALL...A BIT LESS COVERAGE OF
SHOWERS AND STORMS...ESPECIALLY FOR THE COASTAL ZONES. RAIN CHANCES
PROGGED AT 20-30% COASTAL COUNTIES AND 30-40% INLAND. HIGHS AGAIN IN
THE LOWER TO MID 90S.
.LONG TERM...DEEPER MOISTURE WILL START ADVECT INTO THE REGION BY
LATE WEDNESDAY AND CONTINUE MORE EARNESTLY THROUGH THE END OF THE
WEEK. INVERTED MEAN MID LAYER INVERTED TROF AND TUTT WILL APPROACH
AND MOVE THROUGH THE REGION AND RESIDE EAST OF THE FL PENINSULA BY
EARLY THURSDAY. BEHIND THIS FEATURE ABOVE NORMAL CHANCES OF
PRECIPITATION...ESPECIALLY ACROSS NE FL WITH HIGHER END CHANCE OF
POPS THURSDAY AND FRIDAY AFTERNOON AND EARLY EVENING. GOING INTO
NEXT WEEKEND THE UPPER LEVEL RIDGE AXIS MAINTAINS THE SAME POSITION
AS THE CURRENT WX PATTERN WITH HIGH PRESSURE OVER SOUTHERN GEORGIA.
THIS MEAN HIGH PRESSURE AREA SLIDES NORTHEASTWARD OVER THE NE
SEABOARD DURING THE BEGINNING OF NEXT WEEK. THIS WILL ALLOW LIGHTER
SLY SFC WINDS TO CONTINUE EARLY NEXT WEEK WITH MERGING SEA BREEZES
IN THE AFTERNOON AND EARLY EVENING HOURS. ELECTED TO KEEP SCATTERED
SHWRS AND TSTMS NEXT WEEK WITH DEEP MOISTURE REMAINING INTACT.
TEMPERATURES WITHIN A COUPLE DEGREES OF NORMAL WILL PREVAIL.
&&
.AVIATION...PREVAILING VFR TODAY. OCNL MVFR VSBY EXPECTED AROUND GNV
AND VQQ TERMINALS 08Z-12Z. WITH POPS GENERALLY AT OR BELOW 50% WILL
MAINTAIN VCTS TSTMS EXCEPT FOR GNV WHERE PROBS ARE SUFFICIENTLY HIGH
TO GO WITH TEMPO GROUP BY 21Z.
&&
.MARINE...S/SE WINDS UNDER 15 KT WILL PREVAIL INTO THE UPCOMING
WEEKEND WITH SEAS MAINLY 2-3 FT. ISOLATED SHOWERS/TSTMS WILL PREVAIL
THROUGH MIDWEEK...WITH SOME INCREASE LATE WEEK AS A WEAK WAVE
APPROACHES THE WATERS.
RIP CURRENTS: GENERAL LOW RISK THROUGH WEDNESDAY WITH FAIRLY SMALL
SWELLS AROUND 1-2 FT AND WEAK ONSHORE EXCEPT FOR BRIEF WIND INCREASE
ASSOCD E COAST SEA BREEZE IN THE AFTERNOONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 95 73 95 73 / 60 30 40 30
SSI 89 76 88 76 / 30 10 20 10
JAX 92 73 92 73 / 40 20 30 20
SGJ 88 74 88 75 / 30 10 20 10
GNV 92 71 92 71 / 50 30 30 30
OCF 92 71 93 71 / 50 30 40 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/CORDERO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
954 PM CDT WED SEP 3 2014
.DISCUSSION...
904 PM CDT
ONLY MINOR ADJUSTMENTS TONIGHT. BUT THE GREATEST CHALLENGE RESIDES
WITH PRECIP TIMING...COVERAGE. GUIDANCE MEMBERS DIFFERS ON TIMING
AND PLACEMENT OF CONVECTION/PRECIP OVERNIGHT. THERE IS A WEAK MID-
LVL WAVE SLIDING EAST ACROSS CENTRAL IOWA THAT THE RAP CONTINUES
TO LEAN TOWARDS THE FOCAL POINT OVERNIGHT...WITH DEVELOPMENT
CLOSER TO MIDNIGHT ALONG THE MISS RIVER. THERE HAS BEEN SOME
ISOLATED SHOWERS/THUNDERSTORMS ACROSS SOUTHEAST IOWA SLIDING EAST
INTO IL...HOWEVER THE TRENDS HAS BEEN THAT THIS PRECIP WOULD
WEAKEN. THE NOSE OF THE LLVL JET AND THETA-E IS LIFTING
NORTH...WHICH COUPLED WITH LLVL MOISTURE STEADILY INCREASING WOULD
POINT TOWARDS A POTENTIAL FOR INCREASED PRECIP OVERNIGHT OR CLOSER
TO 8-12Z. WILL NUDGE POPS UP TO ACCOUNT FOR THIS...WITH THE FOCUS
BEING AFT MIDNIGHT AND CLOSER TO DAYBREAK.
BEACHLER
//PREV DISCUSSION...
252 PM CDT
SHORT TERM...
FOR THE REMAINDER OF THIS AFTERNOON AND INTO THIS EVENING...QUIET
WEATHER CONDITIONS WILL PREVAIL AS SFC HIGH PRESSURE MOVES OFF TO
THE EAST AND LOW PRESSURE DEVELOPS OVER THE NORTHERN PLAINS.
ALOFT...BROAD UPPER RIDGING EXTENDS ACROSS THE SRN CONUS WITH ZONAL
FLOW OVER THE NRN CONUS. WINDS ACROSS THE AREA AT THE SFC HAVE BEEN
VERY LIGHT...WHICH HAS ALLOWED A LAKE BREEZE TO FORM...BUT SLIGHTLY
STRONGER WINDS ALOFT HAVE KEPT THE LAKE BREEZE BOUNDARY FROM PUSHING
INLAND MUCH FARTHER THAN DOWNTOWN CHICAGO. SO...WHILE MUCH OF THE
AREA WILL SEE TEMPERATURES TOP OUT IN THE LOWER TO MIDDLE 80S...THE
ILLINOIS LAKEFRONT HAS REMAINED MUCH COOLER WITH HIGHS TODAY TOPPING
OUT IN THE MIDDLE 70S. A FEW WEAK SHORT WAVES ARE RIPPLING THROUGH
THE ZONAL FLOW...GENERATING AREAS OF SHOWERS AND THUNDERSTORMS...BUT
NONE ARE CURRENTLY CLOSE TO THE LOCAL AREA.
INTO THIS EVENING...THERE WILL BE AN INCREASING CHANCE FOR
THUNDERSTORMS AS MOISTURE STREAMS NWD AROUND THE WRN PERIPHERY OF
THE SFC HIGH AS SOUTHERLY FLOW DEVELOPS. BY LATE THIS
EVENING...ANTICIPATE A STRONG CONVECTIVE COMPLEX TO DEVELOP OVER THE
UPPER MISSISSIPPI VALLEY ON THE LEADING EDGE OF A STRONG LOW LEVEL
JET WHERE SPC HAS OUTLOOKED A SLIGHT RISK FOR SEVERE THUNDERSTORMS.
THE MAIN QUESTION REMAINS AS TO HOW THE CONVECTIVE COMPLEX WILL
EVOLVE THROUGH THE EVENING AND OVERNIGHT. THE ANTICIPATION IS THAT
THE SYSTEM MAY DEVELOP INTO A BOWING LINE OR SQUALL LINE OVERNIGHT
AND PROPAGATE TO THE SOUTHEAST...ACROSS WISCONSIN. THE LATEST HIGH
RES MODEL GUIDANCE...INCLUDING THE LOCAL WRF...SUGGEST THAT THE LINE
OF THUNDERSTORMS MAY HANG TOGETHER LONG ENOUGH THE REACH NRN/NWRN IL
AFTER MIDNIGHT AND INTO THE EARLY MORNING HOURS BEFORE DISSIPATING.
HOWEVER...SINCE THERE IS STILL SOME UNCERTAINTY TO THE TIMING AND
TRACK OF THE SYSTEM...HAVE KEPT POPS IN THE CHANCE RANGE AND
CONFINED THE MENTION OF PCPN TO THE NRN TIER COUNTIES OF IL ALONG
THE WISCONSIN BORDER. WHILE THERE IS STILL A CHANCE THAT SOME STRAY
SHOWERS OR THUNDERSTORMS COULD LINGER INTO THE MORNING HOURS
TOMORROW...GENERALLY EXPECT THAT THE REST OF THE DAY THURSDAY SHOULD
BE DRY.
THE MAIN CONCERN FOR THURSDAY WILL BE THE TEMPERATURE FORECAST. THE
UPPER LEVEL PATTERN WILL BEGIN TO SHOW SOME AMPLIFICATION AS THE
UPPER RIDGE BUILDS ACROSS THE MIDWEST AND GREAT LAKES WHILE AN UPPER
LOW MOVING EWD FROM THE PAC NORTHWEST TRACKS ACROSS THE SRN CANADIAN
PRAIRIES. THE MAIN EFFECT FOR THE LOCAL AREA WILL BE A CONTINUATION
OF PUMPING UP LOW LEVEL MOISTURE...WITH SFC DEWPOINT LIKELY CLIMBING
INTO THE LOW 70S. THE VARIOUS AND SUNDRY MODELS ARE IN RELATIVELY
GOOD AGREEMENT ON BRINGING 850MB TEMPS OF 22-23C ACROSS THE AREA.
UNDER FULL SUNSHINE...THIS WOULD IMPLY MAX TEMPS IN THE LOW 90S.
HOWEVER...SOME RESIDUAL CLOUD COVER...EVEN PARTIAL CLOUD
COVER...COULD LIMIT SLIGHTLY THE POTENTIAL MAXIMUM
WARMING...SO...HAVE MAINTAINED THE GOING FORECAST OF MAX TEMPS IN
THE UPPER 80S TO SOME AREAS AROUND 90-91F. THIS COMBINATION OF
TEMPERATURES AROUND 90F WITH DEWPOINTS IN THE LOW 70S WOULD GENERATE
MAX HEAT INDEX VALUES CLOSE TO 100F. SO...WHILE HEAT ADVISORY
CRITERIA WILL LIKELY NOT BE MET...IT WILL CERTAINLY BE A HOT AND
HUMID DAY...THE LIKES OF WHICH HAS BEEN FEW AND FAR BETWEEN THIS
SUMMER.
THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL COME THURSDAY NIGHT AND
FRIDAY AS A SFC LOW DEVELOPS OVER THE CNTRL PLAINS TRACKS NORTHEAST
ACROSS THE UPPER MISSOURI VALLEY AND INTO THE UPPER MISSISSIPPI
VALLEY THURSDAY. THIS SFC LOW WILL DRAG A TRAILING COLD FRONT
ACROSS THE UPPER MISSISSIPPI VALLEY BY THURSDAY EVENING. THE MODEL
GUIDANCE HAS BEEN RELATIVELY CONSISTENT IN ADVERTISING A RELATIVELY
STRONG COLD FRONT ASSOCIATED WITH THE DEEPENING UPPER LEVEL LONGWAVE
TROUGH DROPPING INTO THE NRN PLAINS. THIS IS SHAPING UP TO BE A
RATHER DYNAMIC SYSTEM WITH STRONG UPPER FORCING WITH THE 100KT+ JET
ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES...A STRONG MID
LEVEL TROUGH AND SFC COLD FRONT. ALSO...THE MODELS ARE SHOWING
SIGNIFICANT MOISTURE POOLING AHEAD OF THE SFC FRONT WITH PWATS OF 2
INCHES ALONG THE BOUNDARY. WHILE THE STRONGEST UPPER LEVEL FORCING
WILL BE WELL NORTH OF THE CWA...AS SPC OUTLOOKS A SLIGHT RISK OVER
WISCONSIN AND THE WESTERN GREAT LAKES IN THE DAY 2 OUTLOOK...SO THE
GREATEST SEVERE POTENTIAL SHOULD BE TO THE NORTH...THERE WILL STILL
BE THE POTENTIAL FOR STRONG THUNDERSTORMS PRODUCING LOCALLY HEAVY
RAINFALL. AS THE SYSTEM SHOULD BE QUICKLY PROGRESSIVE...WIDESPREAD
FLOODING SHOULD NOT BE A MAJOR CONCERN...BUT LOCALIZED FLOODING OR
FLASH FLOODING IS A POSSIBILITY IF ANY TRAINING SETS UP AS
INDIVIDUAL CELLS TRACK NEWD WHILE THE LARGER SCALE SYSTEM PROGRESSES
EWD.
FORECAST CONFIDENCE BEGINS TO DIMINISH INTO LATE FRIDAY NIGHT AND
EARLY SATURDAY AND WHEN THE PCPN WILL CLEAR THE CWA. HAVE GENERALLY
BEEN FOLLOWING THE TREND OF THE ECMWF WHICH INDICATES SOME LINGERING
PCPN OVER THE SERN PORTIONS OF THE CWA INTO SATURDAY MORNING WHILE
THE GFS IS A LITTLE SLOW. CURRENTLY FAVOR A FASTER PROGRESSION
GIVEN RELATIVELY LOW AMPLITUDE...FAST FLOW ALOFT...SO...WILL GO DRY
BY SATURDAY AFTERNOON.
FOR THE LONGER TERM...FROM SATURDAY AFTERNOON AND INTO THE MIDDLE OF
NEXT WEEK. EXPECT THAT THE REMAINDER OF THE WEEKEND AND EARLY NEXT
WEEK SHOULD BE DRY...BUT ON THE COOLER SIDE AS HIGH PRESSURE BUILDS
ACROSS THE MIDWEST WHILE A QUICK MOVING LOW SCOOTS ACROSS THE UPPER
GREAT LAKES...SETTING UP LIGHT FLOW OFF OF THE LAKE. BY MONDAY
NIGHT AND INTO TUESDAY...ANOTHER SYSTEM IS EXPECTED TO DEVELOP OVER
THE CNTRL PLAINS...DRAGGING ANOTHER COLD FRONT ACROSS THE
AREA...WHICH WILL BRING CHANCES FOR MORE SHOWERS AND THUNDERSTORMS
BY TUESDAY AND WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* CHANCE FOR THUNDERSTORMS EARLY THURSDAY.
* GUSTY SW WINDS THURSDAY FROM MID MORNING ON.
BMD
//DISCUSSION...UPDATED 00Z...
MAIN FORECAST CONCERN WILL BE PINNING DOWN OVERNIGHT CHANCES FOR
THUNDERSTORMS. A WARM FRONT WILL LIFT ACROSS THE REGION TONIGHT WITH
A LOW LEVEL JET DEVELOPING OFF TO OUR WEST/NORTHWEST SPARKING OFF
OVERNIGHT THUNDERSTORMS. THE FOCUS OF THE LOW LEVEL JET WILL BE INTO
PORTIONS OF NORTHERN IOWA AND MINNESOTA TONIGHT BUT MODERATE THETA-E
ADVECTION WILL STRETCH SOUTH ALONG THE MISSISSIPPI VALLEY LATE
TONIGHT WHERE ADDITIONAL THUNDERSTORMS ARE POSSIBLE...THOUGH CHANCES
WILL WANE AS YOU MOVE FARTHER SOUTH. CURRENTLY THERE IS A MIX IN
GUIDANCE AS TO WHETHER OR NOT THE LINE OF THUNDERSTORMS WILL EXTEND
AS FAR SOUTH AS THE NORTHERN ILLINOIS TERMINALS...THOUGH BASED ON
TIMING OF THE BEST MID LEVEL WARM ADVECTION...IT APPEARS THAT RFD
WILL HAVE THE BEST CHANCE. FARTHER EAST...THE LINE OF THUNDERSTORMS
WILL BE LOSING STEAM AS IT MOVES INTO DRIER AIR AND THE LOW LEVEL
JET STARTS TO WEAKEN AND VEER DIURNALLY. WILL UPGRADE THE PROB30 AT
RFD BUT MAINTAIN THE PROB30 FOR TSRA FOR THE CHICAGO TERMINALS AND
ANTICIPATE DROPPING MENTION WHEN WE COME WITHIN 9 HOURS BASED ON
THIS REASONING UNLESS THERE ARE ANY SIGNIFICANT CHANGES BY THE 03Z
UPDATE. OTHERWISE...WINDS WILL RAMP UP MID MORNING THURSDAY WITH
GUSTS INTO THE LOW AND OCCASIONALLY MID 20 KT RANGE THROUGH THE
AFTERNOON. OUTSIDE OF THE LOW PRECIP CHANCES...VFR CONDITIONS WILL
PREVAIL.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN WINDS AND VFR CONDITIONS.
* LOW CONFIDENCE IN TSRA REACHING ORD/MDW.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC TSRA.
SATURDAY THROUGH MONDAY...VFR
TUESDAY...CHC TSRA.
BMD
&&
.MARINE...
218 PM CDT
STRONG SOUTH TO SOUTHWEST WINDS THURSDAY AND THURSDAY NIGHT WILL BE
THE MAIN FOCUS OF THE FORECAST. CURRENTLY...HIGH PRESSURE IS
STRETCHED ACROSS THE APPALACHIANS WITH A WEAKER RIDGE AXIS ACROSS
LAKE MICHIGAN. LOW PRESSURE IS SPREAD ACROSS THE NORTHERN PLAINS AND
WILL CONSOLIDATE AS IT LIFTS NORTHEAST ACROSS NORTHERN MINNESOTA AND
INTO WESTERN ONTARIO INTO FRIDAY. THIS WILL BRING A STRENGTHENING
PRESSURE GRADIENT ACROSS LAKE MICHIGAN STARTING TONIGHT WHICH WILL
BRING AN INCREASING SOUTH WIND. THE STRONGEST WINDS ARE EXPECTED
THURSDAY EVENING/NIGHT AS THE LOW DEEPENS AS IT TRACKS EASTWARD
ACROSS NORTH CENTRAL ONTARIO. FORTUNATELY WARM AIR WILL BE IN PLACE
ACROSS THE LAKE WHICH WILL LIMIT MIXING AND WILL LIKELY KEEP WIND
SPEEDS BELOW GALE FORCE. THE STRONGEST WINDS WILL BE ACROSS CENTRAL
AND NORTHERN LAKE MICHIGAN WITH SPEEDS TO 30 KT EXPECTED. WINDS WILL
STRENGTHEN QUICKLY IN THE FIRST FEW HUNDRED FEET ABOVE THE LAKE
SURFACE SO SOME OF THE TALLEST PILOT HOUSES MAY SEE 35-40 KT WINDS
WHILE WINDS CLOSER TO THE SURFACE REMAIN NEAR 30 KT. A COOL FRONT
WILL CROSS THE LAKE FRIDAY MORNING TURNING WINDS NORTHERLY BUT THE
GRADIENT WILL QUICKLY SLACKEN ALLOWING SPEEDS TO DIMINISH. WITH
SOUTH TO SOUTHWEST WINDS BLOWING OFFSHORE ACROSS THE IL/IN NEARSHORE
WATERS THURSDAY/THURSDAY NIGHT BETTER MIXING WILL OCCUR OVER THE
NEARSHORE WATERS. EXPECT GUSTS TO AROUND 25 KT THURSDAY AFTERNOON
WITH PEAK MIXING BUT THEN EASE AFTER DARK THURSDAY EVENING. WILL
HOIST A SMALL CRAFT ADVISORY FROM LATE THURSDAY MORNING THROUGH THE
EARLY EVENING. HIGH PRESSURE WILL SETTLE SOUTHWARD INTO THE CENTRAL
PLAINS KEEPING A DECENT PRESSURE GRADIENT ACROSS SOUTHERN LAKE
MICHIGAN FRIDAY AFTERNOON THROUGH SATURDAY. SPEEDS REMAIN JUST
BELOW SMALL CRAFT CRITERIA BUT THE SUSTAINED PERIOD OF LONGER FETCH
MAY BRING WAVES TO SMALL CRAFT CRITERIA LATE FRIDAY NIGHT THROUGH
THE DAY SATURDAY.
HIGH PRESSURE RIDGE WILL SPREAD ACROSS THE ENTIRE LAKE LATER
SATURDAY ALLOWING WINDS TO DIMINISH INTO SATURDAY NIGHT. THE HIGH
WILL GRADUALLY WORK EASTWARD THROUGH MONDAY KEEPING WINDS LIGHT
OVERALL WITH A TENDENCY TO TURN ONSHORE SUNDAY AND MONDAY AFTERNOON.
A STEADIER SOUTHERLY WIND IS EXPECTED TO RETURN INTO TUESDAY.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM THURSDAY TO 10 PM THURSDAY.
&&
$$
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
909 PM CDT WED SEP 3 2014
.DISCUSSION...
904 PM CDT
ONLY MINOR ADJUSTMENTS TONIGHT. BUT THE GREATEST CHALLENGE RESIDES
WITH PRECIP TIMING...COVERAGE. GUIDANCE MEMBERS DIFFERS ON TIMING
AND PLACEMENT OF CONVECTION/PRECIP OVERNIGHT. THERE IS A WEAK MID-
LVL WAVE SLIDING EAST ACROSS CENTRAL IOWA THAT THE RAP CONTINUES
TO LEAN TOWARDS THE FOCAL POINT OVERNIGHT...WITH DEVELOPMENT
CLOSER TO MIDNIGHT ALONG THE MISS RIVER. THERE HAS BEEN SOME
ISOLATED SHOWERS/THUNDERSTORMS ACROSS SOUTHEAST IOWA SLIDING EAST
INTO IL...HOWEVER THE TRENDS HAS BEEN THAT THIS PRECIP WOULD
WEAKEN. THE NOSE OF THE LLVL JET AND THETA-E IS LIFTING
NORTH...WHICH COUPLED WITH LLVL MOISTURE STEADILY INCREASING WOULD
POINT TOWARDS A POTENTIAL FOR INCREASED PRECIP OVERNIGHT OR CLOSER
TO 8-12Z. WILL NUDGE POPS UP TO ACCOUNT FOR THIS...WITH THE FOCUS
BEING AFT MIDNIGHT AND CLOSER TO DAYBREAK.
BEACHLER
&&
.PREV DISCUSSION...
252 PM CDT
SHORT TERM...
FOR THE REMAINDER OF THIS AFTERNOON AND INTO THIS EVENING...QUIET
WEATHER CONDITIONS WILL PREVAIL AS SFC HIGH PRESSURE MOVES OFF TO
THE EAST AND LOW PRESSURE DEVELOPS OVER THE NORTHERN PLAINS.
ALOFT...BROAD UPPER RIDGING EXTENDS ACROSS THE SRN CONUS WITH ZONAL
FLOW OVER THE NRN CONUS. WINDS ACROSS THE AREA AT THE SFC HAVE BEEN
VERY LIGHT...WHICH HAS ALLOWED A LAKE BREEZE TO FORM...BUT SLIGHTLY
STRONGER WINDS ALOFT HAVE KEPT THE LAKE BREEZE BOUNDARY FROM PUSHING
INLAND MUCH FARTHER THAN DOWNTOWN CHICAGO. SO...WHILE MUCH OF THE
AREA WILL SEE TEMPERATURES TOP OUT IN THE LOWER TO MIDDLE 80S...THE
ILLINOIS LAKEFRONT HAS REMAINED MUCH COOLER WITH HIGHS TODAY TOPPING
OUT IN THE MIDDLE 70S. A FEW WEAK SHORT WAVES ARE RIPPLING THROUGH
THE ZONAL FLOW...GENERATING AREAS OF SHOWERS AND THUNDERSTORMS...BUT
NONE ARE CURRENTLY CLOSE TO THE LOCAL AREA.
INTO THIS EVENING...THERE WILL BE AN INCREASING CHANCE FOR
THUNDERSTORMS AS MOISTURE STREAMS NWD AROUND THE WRN PERIPHERY OF
THE SFC HIGH AS SOUTHERLY FLOW DEVELOPS. BY LATE THIS
EVENING...ANTICIPATE A STRONG CONVECTIVE COMPLEX TO DEVELOP OVER THE
UPPER MISSISSIPPI VALLEY ON THE LEADING EDGE OF A STRONG LOW LEVEL
JET WHERE SPC HAS OUTLOOKED A SLIGHT RISK FOR SEVERE THUNDERSTORMS.
THE MAIN QUESTION REMAINS AS TO HOW THE CONVECTIVE COMPLEX WILL
EVOLVE THROUGH THE EVENING AND OVERNIGHT. THE ANTICIPATION IS THAT
THE SYSTEM MAY DEVELOP INTO A BOWING LINE OR SQUALL LINE OVERNIGHT
AND PROPAGATE TO THE SOUTHEAST...ACROSS WISCONSIN. THE LATEST HIGH
RES MODEL GUIDANCE...INCLUDING THE LOCAL WRF...SUGGEST THAT THE LINE
OF THUNDERSTORMS MAY HANG TOGETHER LONG ENOUGH THE REACH NRN/NWRN IL
AFTER MIDNIGHT AND INTO THE EARLY MORNING HOURS BEFORE DISSIPATING.
HOWEVER...SINCE THERE IS STILL SOME UNCERTAINTY TO THE TIMING AND
TRACK OF THE SYSTEM...HAVE KEPT POPS IN THE CHANCE RANGE AND
CONFINED THE MENTION OF PCPN TO THE NRN TIER COUNTIES OF IL ALONG
THE WISCONSIN BORDER. WHILE THERE IS STILL A CHANCE THAT SOME STRAY
SHOWERS OR THUNDERSTORMS COULD LINGER INTO THE MORNING HOURS
TOMORROW...GENERALLY EXPECT THAT THE REST OF THE DAY THURSDAY SHOULD
BE DRY.
THE MAIN CONCERN FOR THURSDAY WILL BE THE TEMPERATURE FORECAST. THE
UPPER LEVEL PATTERN WILL BEGIN TO SHOW SOME AMPLIFICATION AS THE
UPPER RIDGE BUILDS ACROSS THE MIDWEST AND GREAT LAKES WHILE AN UPPER
LOW MOVING EWD FROM THE PAC NORTHWEST TRACKS ACROSS THE SRN CANADIAN
PRAIRIES. THE MAIN EFFECT FOR THE LOCAL AREA WILL BE A CONTINUATION
OF PUMPING UP LOW LEVEL MOISTURE...WITH SFC DEWPOINT LIKELY CLIMBING
INTO THE LOW 70S. THE VARIOUS AND SUNDRY MODELS ARE IN RELATIVELY
GOOD AGREEMENT ON BRINGING 850MB TEMPS OF 22-23C ACROSS THE AREA.
UNDER FULL SUNSHINE...THIS WOULD IMPLY MAX TEMPS IN THE LOW 90S.
HOWEVER...SOME RESIDUAL CLOUD COVER...EVEN PARTIAL CLOUD
COVER...COULD LIMIT SLIGHTLY THE POTENTIAL MAXIMUM
WARMING...SO...HAVE MAINTAINED THE GOING FORECAST OF MAX TEMPS IN
THE UPPER 80S TO SOME AREAS AROUND 90-91F. THIS COMBINATION OF
TEMPERATURES AROUND 90F WITH DEWPOINTS IN THE LOW 70S WOULD GENERATE
MAX HEAT INDEX VALUES CLOSE TO 100F. SO...WHILE HEAT ADVISORY
CRITERIA WILL LIKELY NOT BE MET...IT WILL CERTAINLY BE A HOT AND
HUMID DAY...THE LIKES OF WHICH HAS BEEN FEW AND FAR BETWEEN THIS
SUMMER.
THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL COME THURSDAY NIGHT AND
FRIDAY AS A SFC LOW DEVELOPS OVER THE CNTRL PLAINS TRACKS NORTHEAST
ACROSS THE UPPER MISSOURI VALLEY AND INTO THE UPPER MISSISSIPPI
VALLEY THURSDAY. THIS SFC LOW WILL DRAG A TRAILING COLD FRONT
ACROSS THE UPPER MISSISSIPPI VALLEY BY THURSDAY EVENING. THE MODEL
GUIDANCE HAS BEEN RELATIVELY CONSISTENT IN ADVERTISING A RELATIVELY
STRONG COLD FRONT ASSOCIATED WITH THE DEEPENING UPPER LEVEL LONGWAVE
TROUGH DROPPING INTO THE NRN PLAINS. THIS IS SHAPING UP TO BE A
RATHER DYNAMIC SYSTEM WITH STRONG UPPER FORCING WITH THE 100KT+ JET
ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES...A STRONG MID
LEVEL TROUGH AND SFC COLD FRONT. ALSO...THE MODELS ARE SHOWING
SIGNIFICANT MOISTURE POOLING AHEAD OF THE SFC FRONT WITH PWATS OF 2
INCHES ALONG THE BOUNDARY. WHILE THE STRONGEST UPPER LEVEL FORCING
WILL BE WELL NORTH OF THE CWA...AS SPC OUTLOOKS A SLIGHT RISK OVER
WISCONSIN AND THE WESTERN GREAT LAKES IN THE DAY 2 OUTLOOK...SO THE
GREATEST SEVERE POTENTIAL SHOULD BE TO THE NORTH...THERE WILL STILL
BE THE POTENTIAL FOR STRONG THUNDERSTORMS PRODUCING LOCALLY HEAVY
RAINFALL. AS THE SYSTEM SHOULD BE QUICKLY PROGRESSIVE...WIDESPREAD
FLOODING SHOULD NOT BE A MAJOR CONCERN...BUT LOCALIZED FLOODING OR
FLASH FLOODING IS A POSSIBILITY IF ANY TRAINING SETS UP AS
INDIVIDUAL CELLS TRACK NEWD WHILE THE LARGER SCALE SYSTEM PROGRESSES
EWD.
FORECAST CONFIDENCE BEGINS TO DIMINISH INTO LATE FRIDAY NIGHT AND
EARLY SATURDAY AND WHEN THE PCPN WILL CLEAR THE CWA. HAVE GENERALLY
BEEN FOLLOWING THE TREND OF THE ECMWF WHICH INDICATES SOME LINGERING
PCPN OVER THE SERN PORTIONS OF THE CWA INTO SATURDAY MORNING WHILE
THE GFS IS A LITTLE SLOW. CURRENTLY FAVOR A FASTER PROGRESSION
GIVEN RELATIVELY LOW AMPLITUDE...FAST FLOW ALOFT...SO...WILL GO DRY
BY SATURDAY AFTERNOON.
FOR THE LONGER TERM...FROM SATURDAY AFTERNOON AND INTO THE MIDDLE OF
NEXT WEEK. EXPECT THAT THE REMAINDER OF THE WEEKEND AND EARLY NEXT
WEEK SHOULD BE DRY...BUT ON THE COOLER SIDE AS HIGH PRESSURE BUILDS
ACROSS THE MIDWEST WHILE A QUICK MOVING LOW SCOOTS ACROSS THE UPPER
GREAT LAKES...SETTING UP LIGHT FLOW OFF OF THE LAKE. BY MONDAY
NIGHT AND INTO TUESDAY...ANOTHER SYSTEM IS EXPECTED TO DEVELOP OVER
THE CNTRL PLAINS...DRAGGING ANOTHER COLD FRONT ACROSS THE
AREA...WHICH WILL BRING CHANCES FOR MORE SHOWERS AND THUNDERSTORMS
BY TUESDAY AND WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* CHANCE FOR THUNDERSTORMS EARLY THURSDAY.
* GUSTY SW WINDS THURSDAY FROM MID MORNING ON.
BMD
//DISCUSSION...UPDATED 00Z...
MAIN FORECAST CONCERN WILL BE PINNING DOWN OVERNIGHT CHANCES FOR
THUNDERSTORMS. A WARM FRONT WILL LIFT ACROSS THE REGION TONIGHT WITH
A LOW LEVEL JET DEVELOPING OFF TO OUR WEST/NORTHWEST SPARKING OFF
OVERNIGHT THUNDERSTORMS. THE FOCUS OF THE LOW LEVEL JET WILL BE INTO
PORTIONS OF NORTHERN IOWA AND MINNESOTA TONIGHT BUT MODERATE THETA-E
ADVECTION WILL STRETCH SOUTH ALONG THE MISSISSIPPI VALLEY LATE
TONIGHT WHERE ADDITIONAL THUNDERSTORMS ARE POSSIBLE...THOUGH CHANCES
WILL WANE AS YOU MOVE FARTHER SOUTH. CURRENTLY THERE IS A MIX IN
GUIDANCE AS TO WHETHER OR NOT THE LINE OF THUNDERSTORMS WILL EXTEND
AS FAR SOUTH AS THE NORTHERN ILLINOIS TERMINALS...THOUGH BASED ON
TIMING OF THE BEST MID LEVEL WARM ADVECTION...IT APPEARS THAT RFD
WILL HAVE THE BEST CHANCE. FARTHER EAST...THE LINE OF THUNDERSTORMS
WILL BE LOSING STEAM AS IT MOVES INTO DRIER AIR AND THE LOW LEVEL
JET STARTS TO WEAKEN AND VEER DIURNALLY. WILL UPGRADE THE PROB30 AT
RFD BUT MAINTAIN THE PROB30 FOR TSRA FOR THE CHICAGO TERMINALS AND
ANTICIPATE DROPPING MENTION WHEN WE COME WITHIN 9 HOURS BASED ON
THIS REASONING UNLESS THERE ARE ANY SIGNIFICANT CHANGES BY THE 03Z
UPDATE. OTHERWISE...WINDS WILL RAMP UP MID MORNING THURSDAY WITH
GUSTS INTO THE LOW AND OCCASIONALLY MID 20 KT RANGE THROUGH THE
AFTERNOON. OUTSIDE OF THE LOW PRECIP CHANCES...VFR CONDITIONS WILL
PREVAIL.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN WINDS AND VFR CONDITIONS.
* LOW CONFIDENCE IN TSRA REACHING ORD/MDW.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC TSRA.
SATURDAY THROUGH MONDAY...VFR
TUESDAY...CHC TSRA.
BMD
&&
.MARINE...
218 PM CDT
STRONG SOUTH TO SOUTHWEST WINDS THURSDAY AND THURSDAY NIGHT WILL BE
THE MAIN FOCUS OF THE FORECAST. CURRENTLY...HIGH PRESSURE IS
STRETCHED ACROSS THE APPALACHIANS WITH A WEAKER RIDGE AXIS ACROSS
LAKE MICHIGAN. LOW PRESSURE IS SPREAD ACROSS THE NORTHERN PLAINS AND
WILL CONSOLIDATE AS IT LIFTS NORTHEAST ACROSS NORTHERN MINNESOTA AND
INTO WESTERN ONTARIO INTO FRIDAY. THIS WILL BRING A STRENGTHENING
PRESSURE GRADIENT ACROSS LAKE MICHIGAN STARTING TONIGHT WHICH WILL
BRING AN INCREASING SOUTH WIND. THE STRONGEST WINDS ARE EXPECTED
THURSDAY EVENING/NIGHT AS THE LOW DEEPENS AS IT TRACKS EASTWARD
ACROSS NORTH CENTRAL ONTARIO. FORTUNATELY WARM AIR WILL BE IN PLACE
ACROSS THE LAKE WHICH WILL LIMIT MIXING AND WILL LIKELY KEEP WIND
SPEEDS BELOW GALE FORCE. THE STRONGEST WINDS WILL BE ACROSS CENTRAL
AND NORTHERN LAKE MICHIGAN WITH SPEEDS TO 30 KT EXPECTED. WINDS WILL
STRENGTHEN QUICKLY IN THE FIRST FEW HUNDRED FEET ABOVE THE LAKE
SURFACE SO SOME OF THE TALLEST PILOT HOUSES MAY SEE 35-40 KT WINDS
WHILE WINDS CLOSER TO THE SURFACE REMAIN NEAR 30 KT. A COOL FRONT
WILL CROSS THE LAKE FRIDAY MORNING TURNING WINDS NORTHERLY BUT THE
GRADIENT WILL QUICKLY SLACKEN ALLOWING SPEEDS TO DIMINISH. WITH
SOUTH TO SOUTHWEST WINDS BLOWING OFFSHORE ACROSS THE IL/IN NEARSHORE
WATERS THURSDAY/THURSDAY NIGHT BETTER MIXING WILL OCCUR OVER THE
NEARSHORE WATERS. EXPECT GUSTS TO AROUND 25 KT THURSDAY AFTERNOON
WITH PEAK MIXING BUT THEN EASE AFTER DARK THURSDAY EVENING. WILL
HOIST A SMALL CRAFT ADVISORY FROM LATE THURSDAY MORNING THROUGH THE
EARLY EVENING. HIGH PRESSURE WILL SETTLE SOUTHWARD INTO THE CENTRAL
PLAINS KEEPING A DECENT PRESSURE GRADIENT ACROSS SOUTHERN LAKE
MICHIGAN FRIDAY AFTERNOON THROUGH SATURDAY. SPEEDS REMAIN JUST
BELOW SMALL CRAFT CRITERIA BUT THE SUSTAINED PERIOD OF LONGER FETCH
MAY BRING WAVES TO SMALL CRAFT CRITERIA LATE FRIDAY NIGHT THROUGH
THE DAY SATURDAY.
HIGH PRESSURE RIDGE WILL SPREAD ACROSS THE ENTIRE LAKE LATER
SATURDAY ALLOWING WINDS TO DIMINISH INTO SATURDAY NIGHT. THE HIGH
WILL GRADUALLY WORK EASTWARD THROUGH MONDAY KEEPING WINDS LIGHT
OVERALL WITH A TENDENCY TO TURN ONSHORE SUNDAY AND MONDAY AFTERNOON.
A STEADIER SOUTHERLY WIND IS EXPECTED TO RETURN INTO TUESDAY.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM THURSDAY TO 10 PM THURSDAY.
&&
$$
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 NORTHERN INDIANA
346 PM EDT TUE SEP 2 2014
.SYNOPSIS...
ISSUED AT 1051 AM EDT TUE SEP 2 2014
ISOLATED SHOWERS WILL CONTINUE THROUGH AFTERNOON BEFORE
DIMINISHING AS HIGH PRESSURE SETTLES OVER THE REGION. CLOUD COVER
WILL ALSO DIMINISH THROUGH THE AFTERNOON...ALLOWING HIGH
TEMPERATURES TO CLIMB INTO THE UPPER 70S AND LOW 80S. EXPECT A
QUIET NIGHT...WITH MOSTLY CLEAR SKIES AND LOWS IN THE 50S. AREAS
OF FOG WILL DEVELOP TOWARDS WEDNESDAY MORNING...BECOMING LOCALLY
DENSE AT TIMES.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM EDT TUE SEP 2 2014
INFILTRATION OF DRIER AIR INTO THE REGION HAS BEEN SLOW THIS
AFTERNOON...WITH AMPLE BOUNDARY LAYER MOISTURE AMID WASHED OUT
SURFACE BOUNDARY ACROSS THE FORECAST AREA. LOW CLOUDS HAVE BEEN SLOW
TO MIX OUT THROUGH EARLY AFTERNOON BUT LATEST SAT TRENDS SHOWING
MORE SCT LOW LVL CLOUD LAYER...ESPECIALLY NW. ISOLD SHOWERS
CURRENTLY NOTED ON RADAR ACROSS NW/NC IN...GIVEN AMPLE BOUNDARY
LAYER MOISTURE...WEAK SFC CONVERGENCE AND SFC HEATING YIELDING VERY
MODEST SB CAPES UP TO 1000 J/KG ACROSS THE REGION. HRRR AND EVEN
NAM12 HINTING AT ISOLD SHOWER ACTIVITY SPREADING EAST ACROSS THE
FORECAST AREA THROUGH SUNSET. THEREFORE HAVE KEPT AN ISOLD SHOWER
MENTION THROUGH 00Z IN THE FCST. LOW CONFIDENCE FOR THUNDER AT THIS
TIME GIVEN LACK OF FORCING AND WEAK MID LVL LAPSE RATES.
AS RIDGING BUILDS EASTWARD INTO THE OVERNIGHT HOURS...CLEARING SKIES
AND DRY CONDITIONS EXPECTED. WITH SLACKENING GRADIENT AND LOW LVL
MOISTURE...ESPECIALLY SE W/ THE PRECIP OVER THE PAST 24 HRS...FOG
DEVELOPMENT LOOKS LIKELY LATE IN THE OVERNIGHT INTO DAYBREAK
WEDNESDAY. KEPT PREVIOUS FCST IN TACT WITH AREAS OF FOG MENTION FROM
09-12Z. LOW CONFIDENCE WITH THE POSSIBILITY OF DENSE FOG AT THIS
TIME...GIVEN LOW LEVEL DRY ADVECTION AND EXTENSIVE CIRRUS SHIELD
NOTED ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA THIS AFTERNOON.
IF CLOUD COVER IS QUICK TO DIMINISH TONIGHT...W/ LACK OF ANY
CONVECTIVE DEBRIS...THEN DENSE FOG CHANCES WOULD INCREASE TOWARD
TOMORROW MORNING...ESPECIALLY SE. WILL MONITOR TRENDS THROUGH THE
EVENING AND WILL UPDATE AS NECESSARY.
RIDGING BUILDS EAST OF THE AREA THROUGH THE DAY ON WEDNESDAY...WITH
MOSTLY SUNNY SKIES AND FAIR CONDITIONS. KEPT HIGH TEMPS SLIGHTLY
BELOW MAV...ALTHOUGH UPWARD ADJUSTMENT MAY BE NEEDED IN THE NEXT
FCST WITH WAA INTO THE AREA BY THE AFTERNOON HOURS ON THE WESTERN
PERIPHERY OF THE RIDGE.
&&
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 344 PM EDT TUE SEP 2 2014
THE GFS AND ECMWF HAVE APPEARED TO INITIALIZE THE UPSTREAM SHORT
WAVE WELL AND ALSO SEEM HAVE A REASONABLE TRACK WITH THIS SYSTEM
ACROSS THE CONUS THIS WEEK. THE ECMWF AND GFS HAVE ALSO SHOWN GOOD
CONSISTENCY FROM RUN TO RUN WITH THIS SYSTEM THE PAST SEVERAL RUNS.
LOW LEVEL THETA E AND MOISTURE FLUX WILL INCREASE RAPIDLY WEDNESDAY
NIGHT...ESPECIALLY NORTH AND NORTHWEST OF THE AREA. HAVE ADDED A
SMALL CHANCE FOR THUNDERSTORMS OVERNIGHT WEDNESDAY NIGHT ON THE
LEADING EDGE OF THIS THETA E ADVECTION OVER FAR NORTHWEST AREAS...
ESPECIALLY BERRIEN AND LAPORTE COUNTY. KEPT THURSDAY DRY AS THE
PRIMARY LOW LEVEL FORCING SHIFTS NORTH OF THE AREA AND AS A LOW
LEVEL INVERSION INCREASES AT THE BASE OF A WEAK TO MODERATE ELEVATED
MIXED LAYER. THE GFS MAV/MEX TEMPERATURES HAVE BEEN CONSISTENT AT
GENERALLY 5 TO 10 DEGREES ABOVE NORMAL FOR THURSDAY AND FRIDAY AND
APPEAR ON TRACK WITH 850 MB TEMPERATURES APPROACHING 20C.
THUNDERSTORM CHANCES LOOK BEST OVERNIGHT THURSDAY NIGHT THROUGH
FRIDAY NIGHT AS A COLD FRONT APPROACHES. GIVEN THE TIMING OF THE
FRONT AND SUBSTANTIAL INSTABILITY BY LATE THURSDAY AND FRIDAY
AFTERNOON/EARLY EVENING WITH CAPES AS HIGH AS 2000 TO 3000
J/KG...CONCERN FOR AN UPSTREAM CONVECTIVE COMPLEX TO DROP SOUTHEAST
OR SOUTH INTO THE FORECAST AREA AS RICH THETA E SPREADS OVER THE
AREA. EXPANDED THUNDERSTORM CHANCES THURSDAY NIGHT IN THIS REGARD.
OTHERWISE...KEPT STORM CHANCES FRIDAY AND FRIDAY NIGHT. OTHERWISE...
COOLER AND DRIER CONDITIONS CAN BE EXPECTED FOR THE WEEKEND INTO
NEXT WEEK WITH HIGHS IN THE 70S THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 128 PM EDT TUE SEP 2 2014
DIFFUSE FRONTAL BOUNDARY PUSHING SOUTH THROUGH THE AREA AND UPPER
LEVEL SUPPORT SHIFTING NORTHEAST OF THE REGION THIS AFTERNOON
SHOULD YIELD IMPROVING CONDITIONS AT TERMINALS THROUGH THE FIRST
HALF OF THE TAF PD. LINGERING LOW LEVEL STRATUS SLOW TO MIX OUT
THROUGH MIDDAY...ESPECIALLY INVOF KFWA. BUT RECENT SATELLITE
TRENDS SUGGEST RAPID MIXING AND LIFTING/CLEARING OF ANY MVFR CIGS
THIS AFTERNOON. RIDGING BUILDS IN OVERNIGHT WITH CALMING WINDS AND
CLEARING SKIES. LEFT PREVIOUS FCST IN TACT WITH POTENTIAL FOR
MVFR/IFR FOG TOWARD DAYBREAK WEDNESDAY MORNING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MCD
SHORT TERM...NG
LONG TERM...SKIPPER
AVIATION...NG
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
942 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 940 PM CDT WED SEP 3 2014
WEAK MID LEVEL IMPULSE AND DEVELOPING 50 KT LOW LEVEL JET AT 850
MB ON THE KDMX VAD WIND PROFILE HAS TRIGGERED A COUPLE
THUNDERSTORMS JUST WEST OF THE DES MOINES METRO AREA. MOVING EAST
AROUND 25 KTS...THESE WOULD TIME INTO EASTERN IA AFTER 1 AM. HAVE
UPDATED WITH SLIGHT TO CHANCE POPS CENTERED ON THIS FEATURE...
WHICH MAY GROW UPSCALE INTO A SMALL MCS AFFECTING AT LEAST THE
CENTER AND NORTHERN HALF OF THE FORECAST AREA FROM MIDNIGHT
THROUGH AT 4 AM OR SO AS SUGGESTED BY THE 18Z GFS...00Z WRF...AND
PAST FEW HRRR MODEL RUNS.
&&
.SYNOPSIS...
ISSUED AT 313 PM CDT WED SEP 3 2014
A WARM FRONT EXTENDED FROM LOW PRESSURE FAR NW SD TO CENTRAL MO.
CURRENT TEMPERATURES WERE IN THE LOWER TO MID 80S WITH DEWPOINTS IN
THE MID TO UPPER 60S. ELSEWHERE...READINGS WERE IN THE MID 90S FROM
KS TO TX. PRECIPITABLE WATERS WERE OVER 1.5 INCHES IN KS AND MO.
ELEVATED THUNDERSTORMS WERE PERSISTENT IN A LINE ACROSS CENTRAL MN.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 313 PM CDT WED SEP 3 2014
FORECAST FOCUS ON THUNDERSTORM CHANCES LATER TONIGHT THEN A HOT
AND HUMID DAY ON THURSDAY. LOW CONFIDENCE IN CONVECTIVE TRENDS TONIGHT.
TONIGHT...SHOULD BE A QUIET EVENING THEN THUNDERSTORM CHANCES
EXPECTED AFTER MIDNIGHT...ESPECIALLY ACROSS OUR NORTH/NORTHEAST
COUNTIES. MODELS DOING RATHER POORLY WITH PLACEMENT OF CONVECTION
TODAY SO CONFIDENCE IS LOW. SYNOPTICALLY THERE WILL BE A LOW LEVEL
JET STRENGTHENING OVERNIGHT WITH DECENT THETA-E ADVECTION/MOISTURE
TRANSPORT. ON THE LEADING EDGE OF THIS THERE IS THE CHANCE OF
THUNDERSTORMS MAINLY IN OUR NORTHEAST COUNTIES...NORTH/NORTHEAST
OF THE QUAD CITIES METRO. A CAPPING AIRMASS SHOULD SPREAD INTO OUR
SOUTHWEST PREVENTING ANY CONVECTION FROM FORMING THERE.
IN ADDITION...ALSO THIS EVENING STRONG CONVECTION IS EXPECTED TO
DEVELOP IN SOUTHERN MN WHICH WILL GRADUALLY UPSCALE TO A MCS THAT
SHOULD EVENTUALLY TRACK SSE POSSIBLY INTO PORTIONS OF OUR NORTHERN
CWA WELL AFTER MIDNIGHT. THERE WILL BE A FAVORABLE 850 THERMAL
RIDGE TO OUR WEST AND 850 MB THERMAL GRADIENT OF 19-23C FAVORED
CONCEPTUALLY FOR GENESIS/TRACK OF MCS/S DRAPED ACROSS THE CWA. IN
ADDITION...MID LEVEL CAP TO OUR W/SW AND FORWARD PROPAGATING CORFIDI
VECTORS SUPPORTIVE OF CONVECTION REACHING OUR NORTHERN CWA. ECMWF
MODEL FITS THIS SCENARIO THE BEST BUT WITH LOW CONFIDENCE IN ANY
OF THE MODELS BEHAVIOR RECENTLY WILL ONLY KEEP A CHANCE POP FOR
NOW. A WORD OF CAUTION...IF CONVECTION FAILS TO MATERIALIZE IN
SOUTHERN MN AND REMAINS FARTHER NORTH THEN THOSE STORMS WILL PROPAGATE
EASTWARD INTO CENTRAL WISCONSIN...RATHER THAN DIVE SOUTHEAST INTO
THE DVN CWA. WITH INCREASING MOISTURE AND A STEADY SOUTH WIND
TEMPERATURES WILL BE MUCH WARMER COMPARED TO RECENTLY...WITH LOWS
IN THE LOWER 70S AT MOST LOCATIONS.
THURSDAY...HOT WEATHER RETURNS BRIEFLY AS DEEPENING CYCLONE TRACKS
OUT OF THE NORTHERN PLAINS AND TO THE NORTH OF INTERNATIONAL FALLS
MN BY EVENING. MODELS SUGGEST WE WILL BE IN A HOT/MOIST BUT CAPPED
ATMOSPHERE WITH ANY THUNDERSTORM ACTIVITY EARLY IN THE MORNING IN
OUR NORTHEAST SHIFTING AWAY FROM THE CWA. SHOULD BE A MOSTLY SUNNY
AND WINDY DAY WITH SOUTH TO SOUTHWEST WINDS GUSTING AROUND 30 MPH.
MAXIMUM TEMPERATURES WILL SOAR INTO THE LOWER 90S WITH DEWPOINTS
IN THE LOWER 70S. HEAT INDEX VALUES WILL PUSH WELL INTO THE 90S TO
AROUND 100. WILL STILL BE INTERESTING TO SEE IF DEEPER MIXING
ALLOWS FROM DEWPOINTS TO DROP INTO THE MID TO UPPER 60S DURING THE
AFTERNOON. IS SO...THEN HIGH TEMPERATURES MIGHT MAKE IT INTO THE
MID 90S AT SOME LOCATIONS. THE STRONG COLD FRONT WILL STILL BE NORTHWEST
OF THE DVN CWA SO NOT EXPECTING CONVECTION TO ARRIVE IN OUR NW CWA
UNTIL AFTER 7 PM.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 313 PM CDT WED SEP 3 2014
UNSETTLED INTO THE WEEKEND WITH A CHANGEOVER TO EARLY AUTUMN WEATHER
THIS WEEKEND THE MAIN FORECAST ISSUE.
LONG TERM FORECAST CONFIDENCE...OVERALL FAIR OR AVERAGE WITH MAIN
ISSUE STRENGTH AND TIMING OF COOLING EARLY THIS WEEKEND AND ANOTHER
STRONGER COLD FRONT DAY 6-7+ WITH CHANCES OF HEAVY PRECIPITATION.
OVERVIEW...INITIALIZATION AND VERIFICATION GOOD ON SYNOPTIC SCALE
FEATURES WITH MOISTURE ISSUES AGAIN TOO HIGH IN BL IMPACTING CURRENT
AND FUTURE TIMING/PLACEMENT OF CONVECTIVE SYSTEMS. RUN TO RUN INTER
SOLUTION AND TEMPORAL D_PROG_DT TOOLS SUGGEST A 70/30 MIX OF GFS/HI-
RES ECMWF BEST FIT FOR LARGE SCALE FEATURES. THIS SUGGEST LIGHT TO
MODERATE PRECIPITATION WITH FRONT PASSAGE MAINLY ON FRIDAY...THEN
MUCH COOLER WITH EVEN A STRONGER COLD FRONT WITH RISK OF HEAVY
PRECIPITATION FOR THE MIDDLE OF NEXT WEEK.
THURSDAY NIGHT...WEAKENING SPLIT UPPER FLOW AND DIFFLUENT LOW LEVEL
WINDS SUGGEST WEAKENING FORCING A DISSIPATING STAGES OF SHOWERS AND
STORMS WITH CHANCE POPS AND MOSTLY LIGHT SCATTERED RAIN AMOUNTS AND
ISOLATED MODERATE AMOUNTS POSSIBLE IN NON-SEVERE STORMS. TIMING OF
FRONT WILL MAKE FOR 10+ DEGREE THERMAL GRADIENT WITH NEAR 60F LOWS
SUGGESTED FAR NW TO LOWER 70S SE 1/2 OR MORE OF AREA. MOST OF THE
PRECIPITATION SHOULD ARRIVE LATE EVENING NW SECTIONS AND PROGRESS
WITH AND BEHIND THE COOL FRONT.
FRIDAY...SHEAR PROFILE SUPPORTS LOTS OF POST FRONTAL CLOUDS AND NW
WINDS OF 10 TO 15+ MPH TO RESULT IN HIGHS LOWER 70S NW TO AROUND
80F SE 1/3 WITH MODERATE GRADIENT IN-BETWEEN. SHOWERS AND ISOLATED
STORMS EXPECTED BUT AGAIN LOW LEVEL FORCING AND INSTABILITY PROFILES
SUGGEST SCATTERED COVERAGE ATTM. FRIDAY NIGHT...LINGERING POPS
KEPT SE SECTIONS WHICH TRENDS SUGGEST LATER SHIFTS MAY BE ABLE TO
REMOVE. STRONG CAA WITH CLEARING SUGGESTS UPPER 40S NW TO UPPER
50S SE WITH TRENDS SUGGESTING A FEW DEGREES COLDER FOR LATER SHIFTS.
SATURDAY AND SUNDAY...BEAUTIFUL EARLY FALL WEATHER WITH HIGHS LOW TO
MID 70S SATURDAY AND MID TO UPPER 70S SUNDAY. SUNDAY AM LOWS MAY
STILL BE A FEW DEGREES TOO MILD WITH SOME MID 40S POSSIBLE NORTH
SECTIONS. MONDAY AM MINS WITH BL DECOUPLING MAY ALSO SEE SOME UPPER
40S FOR LATER SHIFTS TO CONSIDER.
MONDAY...MILDER WITH HIGHS 75 TO 80F AND POSSIBLY A FEW DEGREES
HIGHER NEEDED FOR LATER SHIFTS TO REASSESS ON SOUTH WINDS 10-20 MPH.
MONDAY NIGHT...ADDED POPS...MAINLY LATE AHEAD OF NEXT STRONG UPPER
TROUGH DEVELOPING THAT WILL MOVE SLOWLY SOUTHEAST FROM NORTH PLAINS.
LOWS 55 TO 60 DEGREES WILL BE IMPACTED BY CLOUD COVER FOR LATER
SHIFTS TO RECONSIDER.
TUESDAY AND WEDNESDAY...SIGNIFICANT MOISTURE POOLING WITH STRONG
KINEMATIC CONVERGENT FIELDS WITH SURFACE FRONT AND DYNAMIC UPPER
TROUGH SUGGEST CONTINUED CHANGES WITH RISK OF SIGNIFICANT RAINS AND
TIMING AND COVERAGE THAT WILL TAKE ANOTHER 24-36 HOURS TO BETTER
CLARIFY. IF SEE SOME SUNNY SKIES THEN HIGHS WILL NEED TO BE BUMPED
BY 5+ DEGREES...OR FROM MID/UPPER 70S TO LOWER 80S...IF NOT MORE.
MINS IN THE LOWER 60S MAY ALSO BE IMPACTED DEPENDING ON CLOUDS THAT
COULD BE A FEW DEGREES HIGHER. LOCAL TECHNIQUES SUGGESTS 1 TO 2
INCHES REASONABLE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 615 PM CDT WED SEP 3 2014
THERE IS A POTENTIAL FOR SCATTERED THUNDERSTORMS LATER TONIGHT AS
A WARM FRONT LIFTS NORTH THROUGH THE REGION. THIS POSSIBILITY
APPEARS GREATEST AT THE CID AND DBQ SITES...WHERE THIS IS
MENTIONED IN PROB30 GROUPS. OTHERWISE...CONDITIONS WILL BE VFR.
THURSDAY WILL BE VERY WARM WITH GUSTY SOUTH WINDS FROM LATE
MORNING THROUGH THE AFTERNOON.
&&
.CLIMATE...
ISSUED AT 313 PM CDT WED SEP 3 2014
WEEK 2...THE 8 TO 14 DAY CPC OUTLOOK IS FOR NEAR TO BELOW NORMAL
TEMPERATURES.
CURRENT TRENDS SUPPORT A STRONG TO SEASONALLY VERY STRONG COLD FRONT
TO ARRIVE LATE NEXT WEEK THAT MAY BRING THE THREAT OF AT LEAST
SCATTERED FROST AROUND THE 12TH TO 15TH OF SEPTEMBER. HIGHS IN THE
60S AND EVEN 50S APPEAR POSSIBLE. THIS FROST RISK SHOULD BE BETTER
KNOWN IN THE NEXT FEW DAYS AS LATEST DATA SOURCES DO SUGGEST IT COULD
IMPACT THE END OF THE GROWING SEASON.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...NICHOLS
AVIATION...SHEETS
CLIMATE...NICHOLS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
623 PM CDT Wed Sep 3 2014
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Thursday)
Issued at 345 PM CDT WED SEP 3 2014
Water vapor loop shows relatively zonal flow across the Central
Plains with weak disturbances moving through. One vort max appears
to be along the border between northwest KS and southwest NE and
seems to be associated with thunderstorm cluster moving into eastern
Nebraska. HRRR has been the only model that developed convection
into central KS this evening, and has done so for the last several
runs. RAP just recently has forecast precip into same general area
in the next several hours. Meanwhile, all other models are keeping
central and eastern KS dry tonight. Confidence is not high enough
that HRRR is right, and thus have continued with POPs below 20% for
tonight in forecast area.
Good pressure gradient across the area tonight will maintain
southerly winds of 10 to 15 kts most areas. This should help keep
minimum temperatures up in the lower to middle 70s.
On Thursday, more sunshine than today and warm temperature aloft
will allow highs to reach the mid 90s most areas. Combined with
dewpoints generally in the upper 60s to lower 70s, peak afternoon
heat indices should reach the 100 to 105 range. Frontal boundary
approaches northwest corner of our CWA around 21Z on Thursday, thus
the chance of late afternoon thunderstorms is continued in that
area.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 345 PM CDT WED SEP 3 2014
Models are in good agreement that the cold front will traverse the
county warning area Thursday night into midday Friday...although
the GFS is the fastest. Convection that develops along and front
Thursday night will have the greatest impact with coverage and
rainfall amounts across the northern 1/3 of the cwa through sunrise
Friday as the front advances southeastward. Will range pops from
likely in the northwest counties to only a slight chance in the
far southeast near Garnett...then keep higher end chance pops all
areas on Friday along and behind the frontal passage and the
approach of a shortwave trough from the central high plains. This
wave will move east of the cwa early Saturday with diminishing
chances for rain north to south as much drier air overspreads the
area. With the frontal passage/cold air advection/clouds and
precip in the area will see much cooler highs from the upper 60s
around Belleville to the middle 80s south of I 35.
This will set the stage for lows in the 50s most areas Friday night
and Saturday night. With the dry air in place and high pressure
center over the area...will keep the area dry late Saturday through
Sunday with highs in the 70s both days.
With the flow aloft slowly transitioning from northwest on Saturday
to a more unsettled west to southwest flow into next week. As it
does...the chances for more thunderstorms will increase and so
will the high temperatures ahead of the next front which is
expected by early Wednesday as a larger scale upper trough moves
into the plains.
Will introduce pops in the north central by Sunday night and then
across the remainder of the cwa Monday into Wednesday.
Highs will generally be in the 80s...cooling slightly into the upper
70s and lower 80s by Wednesday.
&&
.AVIATION...(For the 00Z TAFs through 00Z Thursday Evening)
Issued at 622 PM CDT WED SEP 3 2014
VFR conditions are expected throughout the entire period. Gusty
winds should begin to taper off by 02 UTC, but will reintensify in
the later morning hours tomorrow. There is a marginal chance for scattered
thunderstorms tonight at MHK, but chances are still too low to be
mentioned in this TAF package.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GDP
LONG TERM...63
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS GOODLAND KS
510 PM MDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 150 PM MDT WED SEP 3 2014
WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN
SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT
MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON
MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE
POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE
THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS
SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY
THAN FURTHER NORTH.
AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY
OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE
INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO
OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN
INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS
EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL
MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT
OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE
SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER
TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT
IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW
ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST
AFTER THE SHORT TERM PERIOD.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 242 PM MDT WED SEP 3 2014
THURSDAY NIGHT AND FRIDAY WIDESPREAD RAINFALL...HEAVY AT TIMES...LOOKS
VERY LIKELY FOR THE AREA.
THURSDAY NIGHT MID AND UPPER LEVEL MIXING RATIOS INCREASE AHEAD OF A
COMPACT UPPER LEVEL SHORT WAVE TROUGH THAT WILL MOVE ACROSS THE AREA
THROUGH THE NIGHT. AHEAD OF THE TROUGH ELEVATED CAPE DEVELOPS AS
THE JET AT 750MB NOSES IN THE FROM THE SOUTHEAST...AND PROGRESSES
NORTHWEST ACROSS MOST OF THE AREA THROUGH THE NIGHT. WITH
ISENTROPIC AS WELL AS SYNOPTIC LIFT OCCURRING ALONG THE NOSE OF THIS
JET...ANTICIPATE ELEVATED STORMS TO DEVELOP ALONG IT BY EARLY
EVENING. ELEVATED CAPE ABOVE 750MB MAY BE AS HIGH AS 2500J/KG ALONG
AND SOUTHEAST OF THE NOSE OF THE 750MB JET...WITH INSTABILITY
DECREASING DRAMATICALLY NORTHWEST OF THE NOSE. IF STORMS ARE ABLE
TO TAP INTO THE HIGHER INSTABILITY HAIL UP TO 2 INCHES IN DIAMETER
WILL BE POSSIBLE DUE TO DEEP LAYER SHEAR OF 35KTS. HOWEVER FURTHER
NORTHWEST OF THE JET NOSE HAIL SIZE WILL TAPPER OFF DRAMATICALLY DUE
TO LITTLE TO NO ELEVATED CAPE. PLACED SEVERE WORDING IN THE
FORECAST WHERE SEVERE STORMS WILL BE MOST LIKELY. IN ADDITION TO
THE LARGE HAIL...MEAN STORM MOTION WILL BE AROUND 20MPH AND WILL BE
PARALLEL TO THE NOSE OF THE 750MB JET. THIS WILL LEAD TO SLOW
MOVING TRAINING STORMS CAPABLE OF PRODUCING HEAVY RAINFALL.
ANTICIPATE STORMS TO START OFF AS MORE SUPER CELLULAR IN THE EVENING
WHEN ELEVATED CAPE IS HIGHEST. OVERNIGHT AS THE ELEVATED
INSTABILITY DIMINISHES AND ICE NUCLEI SEEDING FROM UPWIND STORMS
OCCURS...BELIEVE THE HAIL SIZE WILL BECOME SMALLER THAN ONE INCH IN
DIAMETER. HOWEVER HEAVY RAINFALL WILL BECOME MORE OF A THREAT.
FURTHER NORTHWEST OF THE NOSE OF THE 750MB JET 700-500MB THETA-E
LAPSE RATES INDICATE A CONVECTIVELY UNSTABLE ENVIRONMENT DESPITE THE
LACK OF ELEVATED CAPE. WITH UPPER LEVEL SHORT WAVE TROUGH MOVING
ACROSS MOST OF THE AREA THROUGH THE NIGHT DECIDED TO KEEP THE
RAINFALL CHANCES GOING FOR THE REST OF THE AREA...WITH THE BEST
CHANCE FOR RAINFALL ACTUALLY SHIFTING NORTH TOWARD THE NE BORDER
OVERNIGHT FOLLOWING THE HIGHER 700-500MB MIXING RATIOS AND 700-500MB
FRONTOGENESIS.
ASIDE FROM THE WIDESPREAD RAINFALL...A SECOND SURGE OF COOLER AIR
WILL MOVE INTO THE AREA FROM THE NORTH THROUGH THE NIGHT.
FRIDAY MORNING THE UPPER LEVEL SHORT WAVE TROUGH FROM LAST NIGHT
WILL EXIT THE AREA AS ANOTHER SHORT WAVE TROUGH DEEPENS OVER THE
WESTERN PART OF THE AREA. MEANWHILE THE BAND OF 700-500MB
FRONTOGENESIS STRENGTHENS THROUGH THE DAY AND MOVES EAST ACROSS THE
AREA AHEAD OF THIS SECOND SHORT WAVE TROUGH. CAPE WILL BE AROUND
1000J/KG OR LESS SO DO NOT ANTICIPATE A SEVERE THREAT SINCE THE CAPE
PROFILE WILL BE TALL AND NARROW WHICH FAVORS HEAVY RAINFALL. MEAN
STORM MOTION WILL CONTINUE TO BE AROUND 20MPH ALSO FAVORING HEAVY
RAINFALL. ANTICIPATE THE RAINFALL TO END FROM WEST TO EAST DURING
THE AFTERNOON AS THE UPPER LEVEL SHORT WAVE TROUGH EXITS THE AREA.
DUE TO THE COUPLE ROUNDS OF HEAVY RAINFALL POSSIBLE...A FLASH FLOOD
WATCH MAY BE NEEDED BUT WILL HOLD OFF FOR NOW IN ORDER TO GET A GOOD
HANDLE AS TO WHERE THE FLOODING THREAT WILL BE MOST LIKELY.
FRIDAY EVENING THERE MAY BE SOME LINGERING SHOWERS OVER THE EASTERN
PART OF THE AREA AS THE SHORT WAVE TROUGH MOVES EAST. DURING THE
LATE EVENING AND OVERNIGHT HOURS ANOTHER LESS COMPACT UPPER LEVEL
SHORT WAVE TROUGH WILL MOVE THROUGH THE AREA. CURRENTLY THE SOUTH
HALF TO 1/3 HAS THE BEST LIFT AND INSTABILITY SO WILL HAVE THE
HIGHER RAINFALL CHANCES THERE.
SATURDAY THROUGH WEDNESDAY NUMEROUS UPPER LEVEL SHORT WAVE TROUGHS
MOVE ACROSS THE AREA. TWO STRONGER SHORT WAVE TROUGHS WILL MOVE
THROUGH MONDAY AFTERNOON AND MONDAY NIGHT. AS A RESULT WILL HAVE
HIGHER RAINFALL CHANCES FOR MONDAY NIGHT. OTHERWISE LOW RAINFALL
CHANCES ARE FORECAST FOR VARIOUS PARTS OF THE AREA AS THE WEAKER
UPPER LEVEL DISTURBANCES MOVE THROUGH.
TEMPERATURES FOR THE PERIOD WILL START OFF COOLER THAN NORMAL THEN
GRADUALLY WARM TO NEAR NORMAL AS THE COOLER AIR MASS MOVES EAST OF
THE AREA. WEDNESDAY ANOTHER COLD FRONT WILL MOVE INTO THE AREA
BRINGING BELOW NORMAL TEMPERATURES WITH IT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 510 PM MDT WED SEP 3 2014
VFR CONDITIONS EXPECTED AT KGLD AND KMCK THROUGH THE PERIOD.
KGLD...SOUTHWEST WINDS 5-10KTS AT TAF ISSUANCE EXPECTED TO BACK
TO THE SOUTH BY 02Z INCREASING TOWARD 15KTS THEN BECOMING
SOUTHWESTERLY WITH GUSTS AROUND 25KTS FROM 04Z-10Z AS LOW LEVEL
JET KICKS IN. AROUND 11Z WINDS VEER TO THE SOUTHWEST AROUND 12KTS
THEN QUICKLY SHIFT TO THE NORTH/NORTHWEST AT 18G28KTS POSSIBLY
HIGHER BY 14Z AS FRONTAL BOUNDARY AND NICE 3 HOUR PRESSURE RISE
COUPLET MOVE THROUGH. AROUND 18Z WINDS SUBSIDE JUST A BIT AS THE
COUPLET MOVES AWAY BUT STILL EXPECTING NORTH WINDS GUSTING A BIT
OVER 20KTS. BY 21Z A SLOW VEER TO THE NORTHEAST EXPECTED WITH
SPEEDS AROUND 12KTS. NO PRECIPITATION EXPECTED. MODELS HINT AT A
BIT OF MOISTURE AROUND 2K FT DURING THE THE FRONTAL
PASSAGE...RIGHT NOW NOT EXPECTING A BKN DECK AT MVFR CATEGORY. NO
PRECIPITATION EXPECTED.
KMCK...SOUTH WINDS AROUND 10KTS AT TAF ISSUANCE EXPECTED TO
INCREASE TOWARD 13KTS BY 05Z BEFORE SUBSIDING TO 10KTS OR SO FROM
THE SOUTHWEST AROUND 10Z. FRONTAL BOUNDARY MOVES THROUGH AROUND
14Z WITH NORTH WINDS 18G28KTS AS PRESSURE RISE COUPLET MOVES
THROUGH. BY 21Z WINDS VEER TO THE NORTHEAST AROUND 13KTS. SIMILAR
TO KGLD MOISTURE AROUND 2.5K FT MAY PRODUCE A FEW CLOUDS FOR A FEW
HOURS AROUND 14Z...NOT EXPECTED ENOUGH TO CREATE A BKN DECK AND
HIT MVFR CATEGORY. NO PRECIPITATION EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
401 PM CDT TUE SEP 2 2014
...UPDATED FOR LONG TERM...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM CDT TUE SEP 2 2014
THE MID TO UPPER LEVEL FLOW HAS BECOME ZONAL IN THE WAKE OF THE
MINOR SHORTWAVE TROUGH THAT TRAVERSED THE CENTRAL PLAINS MONDAY
EVENING. THE EFFECTIVE FRONTAL BOUNDARY AFTER ALL OF THE NIGHTTIME
CONVECTION WAS SITUATED ACROSS CENTRAL OKLAHOMA AND SOUTHERN
ARKANSAS. SOUTH OF THIS FRONT, TEMPERATURES WERE ABOVE 90 AS OF 2
PM, BUT ON THE COOL SIDE OF THE FRONT, MOST READINGS WERE IN THE
70S TO LOWER 80S. LEE TROUGHING WILL DEVELOP TONIGHT AND
WEDNESDAY IN RESPONSE TO THE ZONAL FLOW. LATE TONIGHT, WARMER MID
LEVEL TEMPERATURES WILL SPREAD ACROSS SOUTHWEST KANSAS, CAPPING
THE ELEVATED MOIST LAYER. THE NAM INDICATES THAT LOW LEVEL WINDS
WILL BECOME SOUTHERLY AS THE WARM FRONT SHIFTS INTO NORTHERN
KANSAS BY WEDNESDAY MORNING. HOWEVER, THE RAP SHOWS THE BOUNDARY
STILL SITUATED ALONG THE KANSAS/OKLAHOMA BORDER AT 12Z. SINCE WE
MAY MAINTAIN UPSLOPE SOUTHEASTERLY FLOW MOST OF THE NIGHT, I OPTED
TO BRING THE LOW CLOUDS AND FOG BACK IN TOWARD 09Z. A MID LEVEL
CLOUD DECK MAY DEVELOP AS THE LOW LEVEL JET DEVELOPS THIS EVENING
AND AN ELEVATED THUNDERSTORM OR TWO CAN`T BE COMPLETELY RULED OUT
OVER SOUTH CENTRAL KANSAS BEFORE THE STRONG CAPPING INVERSION
DEVELOPS.
ON WEDNESDAY, THE LEE TROUGH WILL BECOME ESTABLISHED ACROSS THE
HIGH PLAINS, WITH A WEAK SURFACE DRYLINE SITUATED ACROSS FAR
WESTERN KANSAS. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT
LATE IN THE DAY. HIGH TEMPERATURES WILL BE IN THE MID TO HIGH 90S,WITH
SOME READINGS CLOSE TO 100F.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM CDT TUE SEP 2 2014
A STRONG UPPER LEVEL SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST
WILL MOVE EASTWARD INTO THE NORTHERN PLAINS AND UPPER MIDWEST BY
FRIDAY. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS WESTERN KANSAS AND
THE CENTRAL PLAINS ON THURSDAY BRINGING THE BEST CHANCES FOR SHOWERS
AND THUNDERSTORMS. THE STRONGEST MID AND UPPER LEVEL WINDS WILL BE
IN NEBRASKA, SO NOT EXPECTING LOTS OF SEVERE WITH THE FRONT. CAPE
VALUES AROUND 2000 J/KG WILL BE SUFFICIENT TO PRODUCE SOME SMALL
HAIL AND STRONG WINDS AS THE COLD FRONT SWEEPS ACROSS WESTERN KANSAS
TO NEAR DODGE CITY BY 7 PM THURSDAY AND THROUGH MEDICINE LODGE BY
AROUND MIDNIGHT.
HIGH TEMPERATURES WILL BE VERY WARM AHEAD OF THE COLD FRONT ON
THURSDAY WITH LOW TO MID AND UPPER 90S FORECAST. HIGHS THEN COOL
INTO THE 70S INTO FRIDAY WITH A CONTINUED CHANCE FOR MAINLY
AFTERNOON THUNDERSTORMS BEHIND THE FRONT IN MOIST SURFACE UPSLOPE
FLOW.
BY MONDAY HIGHS WARM BACK INTO THE 80S AS THE COOL HIGH PRESSURE
AREA MOVES EAST AND WARM SOUTHERLY WINDS INCREASE. MORE THUNDERSTORM
CHANCES CONTINUE INTO TUESDAY WITH DISTURBANCES IN SOUTHWEST FLOW
ALOFT AND UPPER JET.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1241 PM CDT TUE SEP 2 2014
ZONAL FLOW IN THE WAKE OF AN UPPER LEVEL DISTURBANCE WILL LEAD TO
RENEWED LEE TROUGHING AND A RETURN TO SOUTHERLY WINDS. AS A
RESULT, THE WARM FRONT OVER OKLAHOMA WILL ADVANCE NORTHWARD INTO
NORTHERN KANSAS TONIGHT. CIGS WILL GRADUALLY IMPROVE AT GCK/DDC TO
VFR THIS AFTERNOON WITH DAYTIME HEATING. GIVEN THE LACK OF UPSLOPE
COMPONENT TO THE WIND LATER TONIGHT, A RETURN TO LOW CIGS AND FOG
IS NOT EXPECTED.
THE RAP NOW INDICATES THAT LOW LEVEL SOUTHEAST FLOW WILL PERSIST
THROUGH 12Z, AND THUS LIFR/IFR CIGS AND VISBYS MAY DEVELOP BY 09Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 97 72 95 / 10 0 10 30
GCK 68 99 70 92 / 0 0 10 40
EHA 66 99 68 94 / 0 10 10 30
LBL 70 98 71 96 / 0 0 10 20
HYS 68 98 72 92 / 10 10 10 50
P28 72 97 74 97 / 30 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...KRUSE
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
351 PM CDT TUE SEP 2 2014
...UPDATED FOR SHORT TERM DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM CDT TUE SEP 2 2014
THE MID TO UPPER LEVEL FLOW HAS BECOME ZONAL IN THE WAKE OF THE
MINOR SHORTWAVE TROUGH THAT TRAVERSED THE CENTRAL PLAINS MONDAY
EVENING. THE EFFECTIVE FRONTAL BOUNDARY AFTER ALL OF THE NIGHTTIME
CONVECTION WAS SITUATED ACROSS CENTRAL OKLAHOMA AND SOUTHERN
ARKANSAS. SOUTH OF THIS FRONT, TEMPERATURES WERE ABOVE 90 AS OF 2
PM, BUT ON THE COOL SIDE OF THE FRONT, MOST READINGS WERE IN THE
70S TO LOWER 80S. LEE TROUGHING WLLL DEVELOP TONIGHT AND WEDNESDAY
IN RESPONSE TO THE ZONAL FLOW. LATE TONIGHT, WARMER MID LEVEL
TEMPERATURES WILL SPREAD ACROSS SOUTHWEST KANSAS, CAPPING THE
ELEVATED MOIST LAYER. THE NAM INDICATES THAT LOW LEVEL WINDS WILL
BECOME SOUTHERLY AS THE WARM FRONT SHIFTS INTO NORTHERN KANSAS BY
WEDNESDAY MORNING. HOWEVER, THE RAP SHOWS THE BOUNDARY STILL
SITUATED ALONG THE KANSAS/OKLAHOMA BORDER AT 12Z. SINCE WE MAY
MAINTAIN UPSLOPE SOUTHEASTERLY FLOW MOST OF THE NIGHT, I OPTED TO
BRING THE LOW CLOUDS AND FOG BACK IN TOWARD 09Z. A MID LEVEL
CLOUD DECK MAY DEVELOP AS THE LOW LEVEL JET DEVELOPS THIS EVENING
AND AN ELEVATED THUNDERSTORM OR TWO CAN`T BE COMPLETELY RULED OUT
OVER SOUTH CENTRAL KANSAS BEFORE THE STRONG CAPPING INVERSION
DEVELOPS.
ON WEDNESDAY, THE LEE TROUGH WILL BECOME ESTABLISHED ACROSS THE
HIGH PLAINS, WITH A WEAK SURFACE DRYLINE SITUATED ACROSS FAR
WESTERN KANSAS. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT
LATE IN THE DAY. HIGH TEMPERATURES WILL BE IN THE MID TO HIGH 90S,WITH
SOME READINGS CLOSE TO 100F.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 326 AM CDT TUE SEP 2 2014
THE LONGWAVE SYNOPTIC FLOW PATTERN WILL BE SOMEWHAT PROGRESSIVE
THROUGH THIS FORECAST, AT LEAST ENOUGH TO BRING SIGNIFICANT SENSIBLE
WEATHER CHANGES TO THE AREA FOR LATE IN THE WEEK. WEDNESDAY AND
THURSDAY WILL SEE SUNNY AND VERY WARM TO HOT TEMPERATURES, AS THE
UPPER JET LIFTS NORTHWARD ACROSS THE NORTHERN TIER OF STATES
ALLOWING THE LARGE SOUTHERN ROCKIES/SOUTHERN PLAINS HIGH PROVIDE
STRONG SUBSIDENCE, FULL INSOLATION AND SOUTHERLY SURFACE WINDS.
THE ECMWF/GFS AND NAM ARE IN EXCELLENT AGREEMENT IN BREAKING DOWN
THIS PATTERN BY THURSDAY AND BRINGING A COLD FRONT THROUGH THE
NORTHERN PLAINS OF WESTERN NEBRASKA AND AS FAR SOUTH AS WEST
CENTRAL KANSAS WITH THE LEADING COOLER AIR SURGE BY THURSDAY
AFTERNOON. CONVECTION COULD OCCUR LATE THURSDAY AFTERNOON OR
EVENING AS WELL WITH THIS COLD FRONT FEATURE, BUT UPPER
SUPPORT/DYNAMICS FOR WIDESPREAD STORM DEVELOPMENT IS LACKING. THE
UPPER JET WILL SINK SOUTHWARD THROUGH THE CENTRAL PLAINS AND
CENTRAL MISSISSIPPI VALLEY, DRIVING THE COLD FRONT FARTHER SOUTH
INTO THE SOUTHERN PLAINS BY SATURDAY MORNING. THE RESULT WILL BE
ADDITONAL CHANCES FOR POSSIBLY EVEN SEVERE STORMS, BUT PERHAPS
JUST POST SURFACE FRONTAL HIGH BASED CONVECTION FROM MID LEVEL
FRONTOGENESIS FRIDAY OR FRIDAY NIGHT WITH MUCH MORE PLEASANT
TEMPERATURES IN THE 70S.
A SLOW WARMING TREND IS LIKELY THROUGH THE LATE PART OF THE WEEKEND
INTO EARLY NEXT WEEK AS RETURN SOUTHERLY FLOW BECOMES REESTABLISHED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1241 PM CDT TUE SEP 2 2014
ZONAL FLOW IN THE WAKE OF AN UPPER LEVEL DISTURBANCE WILL LEAD TO
RENEWED LEE TROUGHING AND A RETURN TO SOUTHERLY WINDS. AS A
RESULT, THE WARM FRONT OVER OKLAHOMA WILL ADVANCE NORTHWARD INTO
NORTHERN KANSAS TONIGHT. CIGS WILL GRADUALLY IMPROVE AT GCK/DDC TO
VFR THIS AFTERNOON WITH DAYTIME HEATING.
THE RAP NOW INDICATES THAT LOW LEVEL SOUTHEAST FLOW WILL PERSIST
THROUGH 12Z, AND THUS LIFR/IFR CIGS AND VISBYS MAY DEVELOP BY 09Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 97 72 95 / 10 0 10 30
GCK 68 99 70 92 / 0 0 10 40
EHA 66 99 68 94 / 0 10 10 30
LBL 70 98 71 96 / 0 0 10 20
HYS 68 98 72 92 / 10 10 10 50
P28 72 97 74 97 / 30 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RUSSELL
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1247 PM CDT TUE SEP 2 2014
...UPDATED FOR AVIATION DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE SEP 2 2014
AS OF 0845 UTC, STRONG THUNDERSTORMS WERE UNDERWAY ACROSS
COMANCHE, BARBER, AND CLARK COUNTY, TIED MOST CLOSELY TO A ZONE
OF FRONTOGENESIS AT AROUND 750MB STRETCHING FROM THE OKLAHOMA
PANHANDLE EAST- NORTHEASTWARD TO FAR SOUTH-CENTRAL KANSAS. THE
HIRES CONVECTIVE- ALLOWING MODELS PICKED UP ON THIS QUITE WELL IN
THE COMPOSITE REFLECTIVITY AND QPF FIELDS. THESE MODELS SHOW THE
CONVECTION MOVING OFF INTO NORTHERN OKLAHOMA BEFORE 1200 UTC, SO
WE WILL TAPER THE POPS DOWN AROUND THIS TIME. EARLIER IN THE
SHIFT, WE ADDED SOME AREAS OF 1/2SM FOG GENERALLY ALONG/SOUTH OF
THE ARKANSAS RIVER IN A ZONE OF SATURATED SURFACE AIR NORTH OF THE
WEAK SURFACE LOW. ANY FOG WHICH DEVELOPS SHOULD ERODE NOT TOO LONG
AFTER SUNRISE, HOWEVER LOW STRATUS IS EXPECTED TO HOLD ON THROUGH
LATE MORNING NORTH OF THE 850MB LOW. THIS MAY THROW A BIT OF A
CURVE BALL IN THE TEMPERATURES TODAY, SO WE ADJUSTED THEM DOWN
(USING A MODIFIED HRRR SOLUTION) OUT ACROSS THE WESTERN HALF FOR
THE FIRST HALF OF THE DAY WITH CLOUDS KEEPING A LID IN THE WARM-
UP. ONCE THE CLOUDS ERODE COMPLETELY BY MIDDAY/EARLY AFTERNOON,
TEMPERATURES WILL WARM INTO THE MID 80S. ANY SURFACE-BASED
CONVECTION LATE THIS AFTERNOON WILL BE DOWN ALONG THE SURFACE
FRONT ACROSS NORTHWEST OKLAHOMA. BY EARLY EVENING, SOME OF THE
THUNDERSTORM ACTIVITY MAY HEAD UP INTO BARBER COUNTY AND EXPAND IN
COVERAGE SOME AS LOW LEVEL JET STRENGTHENS AFTER SUNSET. RICH LOW
LEVEL MOISTURE LEADING TO 2000-3000 J/KG MOST-UNSTABLE CAPE WILL
SUPPORT RENEWED SEVERE WEATHER RISK, EVEN WITH ELEVATED STORMS
DURING THE LATE NIGHT HOURS TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 326 AM CDT TUE SEP 2 2014
THE LONGWAVE SYNOPTIC FLOW PATTERN WILL BE SOMEWHAT PROGRESSIVE
THROUGH THIS FORECAST, AT LEAST ENOUGH TO BRING SIGNIFICANT SENSIBLE
WEATHER CHANGES TO THE AREA FOR LATE IN THE WEEK. WEDNESDAY AND
THURSDAY WILL SEE SUNNY AND VERY WARM TO HOT TEMPERATURES, AS THE
UPPER JET LIFTS NORTHWARD ACROSS THE NORTHERN TIER OF STATES
ALLOWING THE LARGE SOUTHERN ROCKIES/SOUTHERN PLAINS HIGH PROVIDE
STRONG SUBSIDENCE, FULL INSOLATION AND SOUTHERLY SURFACE WINDS.
THE ECMWF/GFS AND NAM ARE IN EXCELLENT AGREEMENT IN BREAKING DOWN
THIS PATTERN BY THURSDAY AND BRINGING A COLD FRONT THROUGH THE
NORTHERN PLAINS OF WESTERN NEBRASKA AND AS FAR SOUTH AS WEST
CENTRAL KANSAS WITH THE LEADING COOLER AIR SURGE BY THURSDAY
AFTERNOON. CONVECTION COULD OCCUR LATE THURSDAY AFTERNOON OR
EVENING AS WELL WITH THIS COLD FRONT FEATURE, BUT UPPER
SUPPORT/DYNAMICS FOR WIDESPREAD STORM DEVELOPMENT IS LACKING. THE
UPPER JET WILL SINK SOUTHWARD THROUGH THE CENTRAL PLAINS AND
CENTRAL MISSISSIPPI VALLEY, DRIVING THE COLD FRONT FARTHER SOUTH
INTO THE SOUTHERN PLAINS BY SATURDAY MORNING. THE RESULT WILL BE
ADDITONAL CHANCES FOR POSSIBLY EVEN SEVERE STORMS, BUT PERHAPS
JUST POST SURFACE FRONTAL HIGH BASED CONVECTION FROM MID LEVEL
FRONTOGENESIS FRIDAY OR FRIDAY NIGHT WITH MUCH MORE PLEASANT
TEMPERATURES IN THE 70S.
A SLOW WARMING TREND IS LIKELY THROUGH THE LATE PART OF THE WEEKEND
INTO EARLY NEXT WEEK AS RETURN SOUTHERLY FLOW BECOMES REESTABLISHED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1241 PM CDT TUE SEP 2 2014
ZONAL FLOW IN THE WAKE OF AN UPPER LEVEL DISTURBANCE WILL LEAD TO
RENEWED LEE TROUGHING AND A RETURN TO SOUTHERLY WINDS. AS A
RESULT, THE WARM FRONT OVER OKLAHOMA WILL ADVANCE NORTHWARD INTO
NORTHERN KANSAS TONIGHT. CIGS WILL GRADUALLY IMPROVE AT GCK/DDC TO
VFR THIS AFTERNOON WITH DAYTIME HEATING. GIVEN THE LACK OF UPSLOPE
COMPONENT TO THE WIND LATER TONIGHT, A RETURN TO LOW CIGS AND FOG
IS NOT EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 84 68 98 71 / 10 10 0 0
GCK 82 67 100 71 / 10 0 0 10
EHA 85 66 99 69 / 0 0 10 10
LBL 86 69 100 72 / 0 10 0 10
HYS 86 67 99 73 / 0 10 10 10
P28 89 72 98 74 / 40 30 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
639 AM CDT TUE SEP 2 2014
...UPDATED AVIATION SECTION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE SEP 2 2014
AS OF 0845 UTC, STRONG THUNDERSTORMS WERE UNDERWAY ACROSS
COMANCHE, BARBER, AND CLARK COUNTY, TIED MOST CLOSELY TO A ZONE
OF FRONTOGENESIS AT AROUND 750MB STRETCHING FROM THE OKLAHOMA
PANHANDLE EAST- NORTHEASTWARD TO FAR SOUTH-CENTRAL KANSAS. THE
HIRES CONVECTIVE- ALLOWING MODELS PICKED UP ON THIS QUITE WELL IN
THE COMPOSITE REFLECTIVITY AND QPF FIELDS. THESE MODELS SHOW THE
CONVECTION MOVING OFF INTO NORTHERN OKLAHOMA BEFORE 1200 UTC, SO
WE WILL TAPER THE POPS DOWN AROUND THIS TIME. EARLIER IN THE
SHIFT, WE ADDED SOME AREAS OF 1/2SM FOG GENERALLY ALONG/SOUTH OF
THE ARKANSAS RIVER IN A ZONE OF SATURATED SURFACE AIR NORTH OF THE
WEAK SURFACE LOW. ANY FOG WHICH DEVELOPS SHOULD ERODE NOT TOO LONG
AFTER SUNRISE, HOWEVER LOW STRATUS IS EXPECTED TO HOLD ON THROUGH
LATE MORNING NORTH OF THE 850MB LOW. THIS MAY THROW A BIT OF A
CURVE BALL IN THE TEMPERATURES TODAY, SO WE ADJUSTED THEM DOWN
(USING A MODIFIED HRRR SOLUTION) OUT ACROSS THE WESTERN HALF FOR
THE FIRST HALF OF THE DAY WITH CLOUDS KEEPING A LID IN THE WARM-
UP. ONCE THE CLOUDS ERODE COMPLETELY BY MIDDAY/EARLY AFTERNOON,
TEMPERATURES WILL WARM INTO THE MID 80S. ANY SURFACE-BASED
CONVECTION LATE THIS AFTERNOON WILL BE DOWN ALONG THE SURFACE
FRONT ACROSS NORTHWEST OKLAHOMA. BY EARLY EVENING, SOME OF THE
THUNDERSTORM ACTIVITY MAY HEAD UP INTO BARBER COUNTY AND EXPAND IN
COVERAGE SOME AS LOW LEVEL JET STRENGTHENS AFTER SUNSET. RICH LOW
LEVEL MOISTURE LEADING TO 2000-3000 J/KG MOST-UNSTABLE CAPE WILL
SUPPORT RENEWED SEVERE WEATHER RISK, EVEN WITH ELEVATED STORMS
DURING THE LATE NIGHT HOURS TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 326 AM CDT TUE SEP 2 2014
THE LONGWAVE SYNOPTIC FLOW PATTERN WILL BE SOMEWHAT PROGRESSIVE
THROUGH THIS FORECAST, AT LEAST ENOUGH TO BRING SIGNIFICANT SENSIBLE
WEATHER CHANGES TO THE AREA FOR LATE IN THE WEEK. WEDNESDAY AND
THURSDAY WILL SEE SUNNY AND VERY WARM TO HOT TEMPERATURES, AS THE
UPPER JET LIFTS NORTHWARD ACROSS THE NORTHERN TIER OF STATES
ALLOWING THE LARGE SOUTHERN ROCKIES/SOUTHERN PLAINS HIGH PROVIDE
STRONG SUBSIDENCE, FULL INSOLATION AND SOUTHERLY SURFACE WINDS.
THE ECMWF/GFS AND NAM ARE IN EXCELLENT AGREEMENT IN BREAKING DOWN
THIS PATTERN BY THURSDAY AND BRINGING A COLD FRONT THROUGH THE
NORTHERN PLAINS OF WESTERN NEBRASKA AND AS FAR SOUTH AS WEST
CENTRAL KANSAS WITH THE LEADING COOLER AIR SURGE BY THURSDAY
AFTERNOON. CONVECTION COULD OCCUR LATE THURSDAY AFTERNOON OR
EVENING AS WELL WITH THIS COLD FRONT FEATURE, BUT UPPER
SUPPORT/DYNAMICS FOR WIDESPREAD STORM DEVELOPMENT IS LACKING. THE
UPPER JET WILL SINK SOUTHWARD THROUGH THE CENTRAL PLAINS AND
CENTRAL MISSISSIPPI VALLEY, DRIVING THE COLD FRONT FARTHER SOUTH
INTO THE SOUTHERN PLAINS BY SATURDAY MORNING. THE RESULT WILL BE
ADDITONAL CHANCES FOR POSSIBLY EVEN SEVERE STORMS, BUT PERHAPS
JUST POST SURFACE FRONTAL HIGH BASED CONVECTION FROM MID LEVEL
FRONTOGENESIS FRIDAY OR FRIDAY NIGHT WITH MUCH MORE PLEASANT
TEMPERATURES IN THE 70S.
A SLOW WARMING TREND IS LIKELY THROUGH THE LATE PART OF THE WEEKEND
INTO EARLY NEXT WEEK AS RETURN SOUTHERLY FLOW BECOMES REESTABLISHED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 637 AM CDT TUE SEP 2 2014
IFR FOG IS STILL POSSIBLE THROUGH AROUND 14 UTC BEFORE INSOLATION
BEGINS TO STRONGLY WARM THE BOUNDARY LAYER THROUGH THE CLOUD LAYER.
VISIBILITY HAS ALREADY FLUCTUATED AROUND 2 MILES AT GCK AND DDC
SINCE ABOUT 9 Z. THUNDERSTORMS SHOULD NO LONGER BE A THREAT TOT HE
TERMINALS THIS MORNING. LIGHT SOUTHEAST WINDS WILL PREVAIL THROUGH
THE AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 87 68 98 71 / 20 10 0 0
GCK 87 67 100 71 / 10 10 0 10
EHA 87 66 99 69 / 10 0 10 10
LBL 87 69 100 72 / 10 10 0 10
HYS 86 67 99 73 / 10 10 10 10
P28 90 72 98 74 / 40 30 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
358 AM CDT TUE SEP 2 2014
...UPDATED SHORT TERM SECTION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE SEP 2 2014
AS OF 0845 UTC, STRONG THUNDERSTORMS WERE UNDERWAY ACROSS
COMANCHE, BARBER, AND CLARK COUNTY, TIED MOST CLOSELY TO A ZONE
OF FRONTOGENESIS AT AROUND 750MB STRETCHING FROM THE OKLAHOMA
PANHANDLE EAST- NORTHEASTWARD TO FAR SOUTH-CENTRAL KANSAS. THE
HIRES CONVECTIVE- ALLOWING MODELS PICKED UP ON THIS QUITE WELL IN
THE COMPOSITE REFLECTIVITY AND QPF FIELDS. THESE MODELS SHOW THE
CONVECTION MOVING OFF INTO NORTHERN OKLAHOMA BEFORE 1200 UTC, SO
WE WILL TAPER THE POPS DOWN AROUND THIS TIME. EARLIER IN THE
SHIFT, WE ADDED SOME AREAS OF 1/2SM FOG GENERALLY ALONG/SOUTH OF
THE ARKANSAS RIVER IN A ZONE OF SATURATED SURFACE AIR NORTH OF THE
WEAK SURFACE LOW. ANY FOG WHICH DEVELOPS SHOULD ERODE NOT TOO LONG
AFTER SUNRISE, HOWEVER LOW STRATUS IS EXPECTED TO HOLD ON THROUGH
LATE MORNING NORTH OF THE 850MB LOW. THIS MAY THROW A BIT OF A
CURVE BALL IN THE TEMPERATURES TODAY, SO WE ADJUSTED THEM DOWN
(USING A MODIFIED HRRR SOLUTION) OUT ACROSS THE WESTERN HALF FOR
THE FIRST HALF OF THE DAY WITH CLOUDS KEEPING A LID IN THE WARM-
UP. ONCE THE CLOUDS ERODE COMPLETELY BY MIDDAY/EARLY AFTERNOON,
TEMPERATURES WILL WARM INTO THE MID 80S. ANY SURFACE-BASED
CONVECTION LATE THIS AFTERNOON WILL BE DOWN ALONG THE SURFACE
FRONT ACROSS NORTHWEST OKLAHOMA. BY EARLY EVENING, SOME OF THE
THUNDERSTORM ACTIVITY MAY HEAD UP INTO BARBER COUNTY AND EXPAND IN
COVERAGE SOME AS LOW LEVEL JET STRENGTHENS AFTER SUNSET. RICH LOW
LEVEL MOISTURE LEADING TO 2000-3000 J/KG MOST-UNSTABLE CAPE WILL
SUPPORT RENEWED SEVERE WEATHER RISK, EVEN WITH ELEVATED STORMS
DURING THE LATE NIGHT HOURS TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 326 AM CDT TUE SEP 2 2014
THE LONGWAVE SYNOPTIC FLOW PATTERN WILL BE SOMEWHAT PROGRESSIVE
THROUGH THIS FORECAST, AT LEAST ENOUGH TO BRING SIGNIFICANT SENSIBLE
WEATHER CHANGES TO THE AREA FOR LATE IN THE WEEK. WEDNESDAY AND
THURSDAY WILL SEE SUNNY AND VERY WARM TO HOT TEMPERATURES, AS THE
UPPER JET LIFTS NORTHWARD ACROSS THE NORTHERN TIER OF STATES
ALLOWING THE LARGE SOUTHERN ROCKIES/SOUTHERN PLAINS HIGH PROVIDE
STRONG SUBSIDENCE, FULL INSOLATION AND SOUTHERLY SURFACE WINDS.
THE ECMWF/GFS AND NAM ARE IN EXCELLENT AGREEMENT IN BREAKING DOWN
THIS PATTERN BY THURSDAY AND BRINGING A COLD FRONT THROUGH THE
NORTHERN PLAINS OF WESTERN NEBRASKA AND AS FAR SOUTH AS WEST
CENTRAL KANSAS WITH THE LEADING COOLER AIR SURGE BY THURSDAY
AFTERNOON. CONVECTION COULD OCCUR LATE THURSDAY AFTERNOON OR
EVENING AS WELL WITH THIS COLD FRONT FEATURE, BUT UPPER
SUPPORT/DYNAMICS FOR WIDESPREAD STORM DEVELOPMENT IS LACKING. THE
UPPER JET WILL SINK SOUTHWARD THROUGH THE CENTRAL PLAINS AND
CENTRAL MISSISSIPPI VALLEY, DRIVING THE COLD FRONT FARTHER SOUTH
INTO THE SOUTHERN PLAINS BY SATURDAY MORNING. THE RESULT WILL BE
ADDITONAL CHANCES FOR POSSIBLY EVEN SEVERE STORMS, BUT PERHAPS
JUST POST SURFACE FRONTAL HIGH BASED CONVECTION FROM MID LEVEL
FRONTOGENESIS FRIDAY OR FRIDAY NIGHT WITH MUCH MORE PLEASANT
TEMPERATURES IN THE 70S.
A SLOW WARMING TREND IS LIKELY THROUGH THE LATE PART OF THE WEEKEND
INTO EARLY NEXT WEEK AS RETURN SOUTHERLY FLOW BECOMES REESTABLISHED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1249 AM CDT TUE SEP 2 2014
SCATTERED SHOWERS AND THUNDERSTORMS ALONG AN ELEVATED FRONTAL
BOUNDARY ABOUT 7000 FT AGL WILL BE CLOSE ENOUGH TO GCK, DDC, AND
EVEN HYS TO JUSTIFY A VCTS GROUP FOR A FEW HOURS OVERNIGHT.
OTHERWISE, WE EXPECT SOME LOW STRATUS TO DEVELOP IN WEAK, BUT
MOIST UPSLOPE FLOW, ESPECIALLY AT GCK AND DDC, SO WE WILL INCLUDE
SOME IFR (AND BRIEFLY LIFR AT GCK) IN THE 10-14Z TIME FRAME
ROUGHLY. THE STRATUS LAYER WILL LIFT IN CEILING AFTER SUNRISE,
HOWEVER IT IS STILL SOMEWHAT UNCLEAR HOW LONG IT WILL TAKE TO
SCATTER OUT. SOME OF THIS LOW STRATUS WILL ADVECT NORTHWARD TO HYS
LATE MORNING, SO WE WILL FORECAST SOME MVFR 1000-1500 CEILING FROM
LATE MORNING UNTIL EARLY AFTERNOON UP THERE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 87 68 98 71 / 20 10 0 0
GCK 87 67 100 71 / 10 10 0 10
EHA 87 66 99 69 / 10 0 10 10
LBL 87 69 100 72 / 10 10 0 10
HYS 86 67 99 73 / 10 10 10 10
P28 90 72 98 74 / 40 30 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1155 PM CDT Mon Sep 1 2014
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Tuesday)
Issued at 319 PM CDT MON SEP 1 2014
Quick cyclonic upper flow remains in place with the core of last
night`s wave already in the Great Lakes and another weaker wave
coming into the High Plains per recent water vapor imagery. The cold
front`s location is hard to nail down behind outflow from the
overnight convection and weak pressure fields, but appears to be
bisecting the local area from southwest to northeast. Lower cloud
under a modest inversion has been rather prevalent today, keeping
temps in the 70s.
Modest convergence persists in east central Kansas this afternoon.
With still some CIN remaining per RAP analysis, confirmed by recent
visible satellite imagery, and the western upper wave staying well
north, storm chances don`t look great, but will maintain some
mention ahead of the front in east central Kansas, diminishing with
time as weak high pressure continues to move across northern sections
of the state. There are some breaks in the clouds to the south, and
some increase in instability is anticipated for the next few hours.
Deep layer is not very high in the weak low level wind fields, but
hard to completely rule out with mixed layer CAPE likely rising to
near 1500 J/kg. As the surface high builds in, winds should be
rather light, and depending on cloud trends particularly with
convection, a fairly good setup for radiational fog will be in place
with cloudy skies and limited mixing today and low cloud scouring
out following the recent heavy rain. Will go ahead with some patchy
fog mention at this point and let later shifts watch trends. Storm
chances continue to look like Tuesday but with the boundary again
possibly not far south, will keep a small chance near it. Better
mixing and insolation should yield highs back into the 80s.
.LONG TERM...(Tuesday Night through Monday)
Issued at 319 PM CDT MON SEP 1 2014
Models continue to show the potential for elevated thunderstorms
and large hail Tuesday night. The one wrinkle is the NAM appears to
be quite a bit stronger in magnitude for both the elevated
instability and effective shear. There is still good theta-e
advection along the nose of the low level jet as well as
isentropic upglide, so I think there should be some storms over
eastern KS. The question is whether they will be strong enough to
produce severe hail. Have continued with a chance POP through the
night and think the potential still exists for some severe storms.
It just may be more marginal than the NAM would suggest.
With the exception of some elevated precip possibly lingering
through the morning Wednesday, the forecast should quiet down as
the models keep the jet stream and synoptic scale energy north of
the forecast through Thursday morning. By Thursday night, a frontal
system is projected to begin moving into the area. There is some
uncertainty in the timing of the frontal system as most solutions
have trended faster with the front, the NAM being the fastest. For
now I`ve not made many changes from the previous forecast thinking
the front would move through mainly Friday and Friday evening with
the higher chances for precip in these periods. However if the
faster trend continues, the POPs may need to be pushed up in the
forecast as well. Have continued to trend POPs down for Saturday
and kept a dry forecast for Sunday with models showing surface
ridging and relatively dryer air over KS. By Monday, there is some
disagreement with the GFS and ECMWF in the amplification of an
upper trough across the west. Because the GFS is the more
amplified solution, it is quick to set up return flow with the
potential for shortwaves within southwesterly flow aloft to pass
near the area. Have taken a conservative approach with the
forecast at this time and have introduced only a slight chance for
precip on Monday until there is a little more agreement in
solutions.
Temps will remain quite warm Wednesday and Thursday as the models
show the thermal ridge over portions of the state. Because of this
have continued with highs in the 90s and lows from around 70 to
the mid 70s. Cold air advection is expected to increase Thursday
night as the front moves through the area. This should bring a
cool down for the weekend with highs in the 70s and lows in the
50s to around 60.
&&
.AVIATION...(For the 06Z TAFs through 06Z Tuesday Night)
Issued at 1149 PM CDT MON SEP 1 2014
Elevated thunderstorms have moved well south and east of the taf
sites. Mid and high level clouds have blanketed the area from the
convection in southern KS, but they are slowly progressing
eastward. Once the clouds clear out there maybe brief periods of
patchy especially during calm winds in the predawn hours. Although the
forecast winds just above the surface may inhibit fog development.
Therefore did not add any tempo for dense fog at this time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...Wolters
AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS JACKSON KY
345 PM EDT TUE SEP 2 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 343 PM EDT TUE SEP 2 2014
A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD
OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF
THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM
WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT
WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW
AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE
THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN
KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE
FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY
MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL
WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE
COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 301 PM EDT TUE SEP 2 2014
THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE
AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE
SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A
WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE
NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN
TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT
ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF
THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT
WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH
ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT
TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR
THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH
MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE
FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE
RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT
BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY
MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE
SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE
RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE
FRONT FINALLY MOVES OUT OF THE AREA.
TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH
HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND
FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION
BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW
NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT
OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER
INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS
THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO
RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE
NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN
THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL
ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL
LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 156 PM EDT TUE SEP 2 2014
EASTERN KENTUCKY IS PRIMED FOR THUNDERSTORMS AS MOIST AND UNSTABLE
CONDITIONS ARE PREVALENT ACROSS THE AREA. THERE IS AN OLD OUTFLOW
BOUNDARY BISECTING THE AREA WHICH WE ARE WATCHING AS A FOCAL POINT
FOR CONVECTIVE INITIATION AND THERE IS ALSO A FRONT WHICH IS MOVING
TOWARD THE AREA FROM THE NORTHWEST WITH LOTS OF PREFRONTAL CONVECTION
OUT AHEAD OF IT. MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES
THIS AFTERNOON AND EVENING EXCEPT FOR IN THE VICINITY OF THE
THUNDERSTORMS AND RAIN SHOWERS. PUT SOME TEMPO CONDITIONS IN THE TAF
AS THE BEST ESTIMATE AS TO WHEN THUNDERSTORMS ARE MOST LIKELY AFFECT
THEM. EXPECT SOME VLIFR TO FORM AT THE TAF STATIONS AS WELL AS THE
VALLEYS LATER THIS EVENING AS THE CONVECTION MOVES OFF TO THE SOUTH
AND EAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JJ
LONG TERM...AR
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
302 PM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 948 AM EDT TUE SEP 2 2014
THE FORECAST FOR THIS AFTERNOON HAS BECOME COMPLICATED BY THE
REMNANTS OF AN MCS OVER THE OHIO VALLEY AND THE OUTFLOW BOUNDARY
WHICH IS CURRENTLY MOVING INTO THE BLUEGRASS. CURRENT THINKING IS
THAT THE OUTFLOW BOUNDARY WILL GENERALLY WEAKEN AS IT CONTINUES
MOVING TO THE SOUTHEAST. THIS SHOULD BE TEMPORARY AND WILL THEN BE
THE FOCUS OF DEVELOPMENT LATER IN THE AFTERNOON. SO PRETTY MUCH GOING
WITH TWO PRONGS. THE FIRST BEING REDEVELOPMENT WITH THE OUTFLOW
BOUNDARY AND THE SECOND BEING THE PREFRONTAL ACTIVITY. THE SEVERE
THREAT TODAY WILL BE EFFECTED BY HOW MUCH DEBRIS CLOUD IS ABLE TO
MOVE INTO THE AREA. THE LOW LEVEL INSTABILITY WILL BE EFFECTED BY
EFFECTED BY THE CLOUDS. THE LATEST NAM BUFFER HAS REALLY BACKED OFF
FROM YESTERDAY WITH HALF THE CAPE THAN WHAT WAS FORECAST YESTERDAY.
ALSO MISSING IS THE DRY AIR POCKETS ALOFT WHICH WOULD HAVE BEEN
HELPFUL FOR WET MICROBURSTS TO OCCUR. CAN NOT RULE OUT SEVERE
THUNDERSTORMS...HOWEVER THE CHANCES HAVE GONE DOWN. MOST LIKELY WILL
STILL SEE A COUPLE OF SEVERE STORMS WITH THIS SYSTEM. UPDATED THE
FORECAST TO REFLECT THE CURRENT CONDITIONS AND MODEL TRENDS.
UPDATE ISSUED AT 649 AM EDT TUE SEP 2 2014
NO SIGNIFICANT CHANGES MADE THIS MORNING. LINE OF SHOWERS AND STORMS
EXTENDS FROM CINCINNATI SOUTHWEST TO THE NORTHWEST SIDE OF
LOUISVILLE. THIS LINE CONTINUES TO SLOWLY WEAKEN AS IT MOVES EAST. IF
IT WERE TO HOLD TOGETHER...LOOKS LIKE IT MAY WORK INTO THE BLUEGRASS
COUNTIES AFTER 13Z. HOWEVER...GIVEN THE TREND THIS SEEMS UNLIKELY AND
AT BEST PERHAPS AN ISOLATED SHOWER CAN HOLD TOGETHER. MAIN CONCERN
CONTINUES TO BE LATER TODAY...PRIMARILY AFTER 2 PM AS OUTFLOW FROM
THIS MORNINGS CONVECTION REDEVELOPS SHOWERS AND STORMS. NOT SURE THE
COVERAGE WILL BE ALL THAT GREAT AFTER LOOKING AT THE LATEST HRRR AND
NEW 06Z MAV GUIDANCE. BOTH OF THESE MODELS HAVE BACKED OFF
SIGNIFICANTLY ON THE CHANCES OF RAIN TODAY. HOWEVER...GOING TO STAY
THE COURSE AS THE TROUGH IS STILL FAIRLY DEFINED AND OUTFLOW HAS
ALREADY DEFINED A BOUNDARY FOR NEW CONVECTION TO DEVELOP.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT TUE SEP 2 2014
PRESENTLY...A SHORTWAVE TROUGH IS PUSHING INTO THE OHIO RIVER VALLEY
REGION. AN MCS DEVELOPED YESTERDAY EVENING HEAD OF THIS TROUGH AND
IS NOW MARCHING EASTWARD INTO CENTRAL/SOUTHERN INDIANA...STRETCHING
BACK TO THE SOUTHWEST ACROSS SOUTHERN ILLINOIS. IR SATELLITE HAS
SHOWN SOME WARMING WITH THE CLOUD TOPS OVER THE PAST HOUR OR
TWO...INDICATING THAT THIS MCS MAY ALREADY BE ON THE DECLINE. IN
FACT...THE HRRR SUPPORTS THE IDEA OF A DYING MCS AS IT TRIES TO PUSH
INTO CENTRAL KENTUCKY TOWARDS DAYBREAK. CANNOT RULE OUT A FEW SHOWERS
PUSHING INTO THE BLUEGRASS SHORTLY AFTER 8 AM...BUT ANTICIPATE MORE
OF THE ACTION WITH THE SHORTWAVE TROUGH WILL COME LATER THIS
AFTERNOON AS WE GENERATE SOME INSTABILITY. WITH THIS IN MIND...PLAN
TO BACK OFF THE POPS THROUGH MIDDAY WITH JUST SOME ISOLATED SHOWERS
FOR AREAS NORTH OF I-64. OUTFLOW FROM THE DYING MCS WILL BE PUSHING
ACROSS EASTERN KENTUCKY EARLY THIS AFTERNOON...AND COULD KICK START
THE CONVECTION AS IT ENCOUNTERS SOME DECENT INSTABILITY. THE FORCING
ALOFT SHOULD ALLOW FOR FAIRLY GOOD SHOWER AND THUNDERSTORM COVERAGE
BY MID TO LATE AFTERNOON. WITH BULK SHEAR VALUES OF 30-40KTS THIS
AFTERNOON...A SEVERE THREAT WOULD EXIST AS THUNDERSTORMS COULD PUT
OUT SOME DAMAGING WIND GUSTS. THE SHEAR PROFILES WEAKEN BY MID
EVENING AND THE LOSS OF DAYTIME INSTABILITY SHOULD YIELD WEAKENING
STORMS AFTER 6 PM. HOWEVER...A FEW GUSTY WINDS MAY STILL BE POSSIBLE
THROUGH 8 OR 9 PM.
THE SHORTWAVE TROUGH WILL STALL A COLD FRONT ACROSS SOUTHERN
KENTUCKY BY LATE THIS EVENING. GIVEN THE PRESENCE OF THIS
BOUNDARY...AND PLENTY OF MOISTURE...IT MAY BE POSSIBLE TO SEE
ISOLATED SHOWERS THROUGH THE NIGHT ACROSS THE SOUTHERN HALF OF
KENTUCKY. THIS BOUNDARY WILL LINGER AROUND INTO WEDNESDAY AND WITH
INSTABILITY AGAIN RAMPING UP DURING THE AFTERNOON...WE COULD BE
LOOKING AT A FEW MORE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. HOWEVER...BY WEDNESDAY...VERY LITTLE SHEAR IS
PRESENT...SO WE SHOULD SEE MORE ORDINARY THUNDERSTORMS WITH NO SEVERE
THREAT.
TEMPERATURES OVER THE NEXT 2 DAYS SHOULD BE FAIRLY SIMILAR TO WHAT WE
HAVE SEEN LATELY WITH HIGHS INTO THE LOW TO MID 80S. SAME CAN BE SAID
FOR LOWS TONIGHT WITH READINGS GENERALLY AROUND 70.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 301 PM EDT TUE SEP 2 2014
THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE
AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE
SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A
WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE
NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN
TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT
ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF
THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT
WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH
ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT
TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR
THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH
MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE
FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE
RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT
BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY
MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE
SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE
RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE
FRONT FINALLY MOVES OUT OF THE AREA.
TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH
HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND
FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION
BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW
NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT
OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER
INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS
THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO
RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE
NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN
THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL
ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL
LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 156 PM EDT TUE SEP 2 2014
EASTERN KENTUCKY IS PRIMED FOR THUNDERSTORMS AS MOIST AND UNSTABLE
CONDITIONS ARE PREVALENT ACROSS THE AREA. THERE IS AN OLD OUTFLOW
BOUNDARY BISECTING THE AREA WHICH WE ARE WATCHING AS A FOCAL POINT
FOR CONVECTIVE INITIATION AND THERE IS ALSO A FRONT WHICH IS MOVING
TOWARD THE AREA FROM THE NORTHWEST WITH LOTS OF PREFRONTAL CONVECTION
OUT AHEAD OF IT. MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES
THIS AFTERNOON AND EVENING EXCEPT FOR IN THE VICINITY OF THE
THUNDERSTORMS AND RAIN SHOWERS. PUT SOME TEMPO CONDITIONS IN THE TAF
AS THE BEST ESTIMATE AS TO WHEN THUNDERSTORMS ARE MOST LIKELY AFFECT
THEM. EXPECT SOME VLIFR TO FORM AT THE TAF STATIONS AS WELL AS THE
VALLEYS LATER THIS EVENING AS THE CONVECTION MOVES OFF TO THE SOUTH
AND EAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...KAS
LONG TERM...AR
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
156 PM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 948 AM EDT TUE SEP 2 2014
THE FORECAST FOR THIS AFTERNOON HAS BECOME COMPLICATED BY THE
REMNANTS OF AN MCS OVER THE OHIO VALLEY AND THE OUTFLOW BOUNDARY
WHICH IS CURRENTLY MOVING INTO THE BLUEGRASS. CURRENT THINKING IS
THAT THE OUTFLOW BOUNDARY WILL GENERALLY WEAKEN AS IT CONTINUES
MOVING TO THE SOUTHEAST. THIS SHOULD BE TEMPORARY AND WILL THEN BE
THE FOCUS OF DEVELOPMENT LATER IN THE AFTERNOON. SO PRETTY MUCH GOING
WITH TWO PRONGS. THE FIRST BEING REDEVELOPMENT WITH THE OUTFLOW
BOUNDARY AND THE SECOND BEING THE PREFRONTAL ACTIVITY. THE SEVERE
THREAT TODAY WILL BE EFFECTED BY HOW MUCH DEBRIS CLOUD IS ABLE TO
MOVE INTO THE AREA. THE LOW LEVEL INSTABILITY WILL BE EFFECTED BY
EFFECTED BY THE CLOUDS. THE LATEST NAM BUFFER HAS REALLY BACKED OFF
FROM YESTERDAY WITH HALF THE CAPE THAN WHAT WAS FORECAST YESTERDAY.
ALSO MISSING IS THE DRY AIR POCKETS ALOFT WHICH WOULD HAVE BEEN
HELPFUL FOR WET MICROBURSTS TO OCCUR. CAN NOT RULE OUT SEVERE
THUNDERSTORMS...HOWEVER THE CHANCES HAVE GONE DOWN. MOST LIKELY WILL
STILL SEE A COUPLE OF SEVERE STORMS WITH THIS SYSTEM. UPDATED THE
FORECAST TO REFLECT THE CURRENT CONDITIONS AND MODEL TRENDS.
UPDATE ISSUED AT 649 AM EDT TUE SEP 2 2014
NO SIGNIFICANT CHANGES MADE THIS MORNING. LINE OF SHOWERS AND STORMS
EXTENDS FROM CINCINNATI SOUTHWEST TO THE NORTHWEST SIDE OF
LOUISVILLE. THIS LINE CONTINUES TO SLOWLY WEAKEN AS IT MOVES EAST. IF
IT WERE TO HOLD TOGETHER...LOOKS LIKE IT MAY WORK INTO THE BLUEGRASS
COUNTIES AFTER 13Z. HOWEVER...GIVEN THE TREND THIS SEEMS UNLIKELY AND
AT BEST PERHAPS AN ISOLATED SHOWER CAN HOLD TOGETHER. MAIN CONCERN
CONTINUES TO BE LATER TODAY...PRIMARILY AFTER 2 PM AS OUTFLOW FROM
THIS MORNINGS CONVECTION REDEVELOPS SHOWERS AND STORMS. NOT SURE THE
COVERAGE WILL BE ALL THAT GREAT AFTER LOOKING AT THE LATEST HRRR AND
NEW 06Z MAV GUIDANCE. BOTH OF THESE MODELS HAVE BACKED OFF
SIGNIFICANTLY ON THE CHANCES OF RAIN TODAY. HOWEVER...GOING TO STAY
THE COURSE AS THE TROUGH IS STILL FAIRLY DEFINED AND OUTFLOW HAS
ALREADY DEFINED A BOUNDARY FOR NEW CONVECTION TO DEVELOP.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT TUE SEP 2 2014
PRESENTLY...A SHORTWAVE TROUGH IS PUSHING INTO THE OHIO RIVER VALLEY
REGION. AN MCS DEVELOPED YESTERDAY EVENING HEAD OF THIS TROUGH AND
IS NOW MARCHING EASTWARD INTO CENTRAL/SOUTHERN INDIANA...STRETCHING
BACK TO THE SOUTHWEST ACROSS SOUTHERN ILLINOIS. IR SATELLITE HAS
SHOWN SOME WARMING WITH THE CLOUD TOPS OVER THE PAST HOUR OR
TWO...INDICATING THAT THIS MCS MAY ALREADY BE ON THE DECLINE. IN
FACT...THE HRRR SUPPORTS THE IDEA OF A DYING MCS AS IT TRIES TO PUSH
INTO CENTRAL KENTUCKY TOWARDS DAYBREAK. CANNOT RULE OUT A FEW SHOWERS
PUSHING INTO THE BLUEGRASS SHORTLY AFTER 8 AM...BUT ANTICIPATE MORE
OF THE ACTION WITH THE SHORTWAVE TROUGH WILL COME LATER THIS
AFTERNOON AS WE GENERATE SOME INSTABILITY. WITH THIS IN MIND...PLAN
TO BACK OFF THE POPS THROUGH MIDDAY WITH JUST SOME ISOLATED SHOWERS
FOR AREAS NORTH OF I-64. OUTFLOW FROM THE DYING MCS WILL BE PUSHING
ACROSS EASTERN KENTUCKY EARLY THIS AFTERNOON...AND COULD KICK START
THE CONVECTION AS IT ENCOUNTERS SOME DECENT INSTABILITY. THE FORCING
ALOFT SHOULD ALLOW FOR FAIRLY GOOD SHOWER AND THUNDERSTORM COVERAGE
BY MID TO LATE AFTERNOON. WITH BULK SHEAR VALUES OF 30-40KTS THIS
AFTERNOON...A SEVERE THREAT WOULD EXIST AS THUNDERSTORMS COULD PUT
OUT SOME DAMAGING WIND GUSTS. THE SHEAR PROFILES WEAKEN BY MID
EVENING AND THE LOSS OF DAYTIME INSTABILITY SHOULD YIELD WEAKENING
STORMS AFTER 6 PM. HOWEVER...A FEW GUSTY WINDS MAY STILL BE POSSIBLE
THROUGH 8 OR 9 PM.
THE SHORTWAVE TROUGH WILL STALL A COLD FRONT ACROSS SOUTHERN
KENTUCKY BY LATE THIS EVENING. GIVEN THE PRESENCE OF THIS
BOUNDARY...AND PLENTY OF MOISTURE...IT MAY BE POSSIBLE TO SEE
ISOLATED SHOWERS THROUGH THE NIGHT ACROSS THE SOUTHERN HALF OF
KENTUCKY. THIS BOUNDARY WILL LINGER AROUND INTO WEDNESDAY AND WITH
INSTABILITY AGAIN RAMPING UP DURING THE AFTERNOON...WE COULD BE
LOOKING AT A FEW MORE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. HOWEVER...BY WEDNESDAY...VERY LITTLE SHEAR IS
PRESENT...SO WE SHOULD SEE MORE ORDINARY THUNDERSTORMS WITH NO SEVERE
THREAT.
TEMPERATURES OVER THE NEXT 2 DAYS SHOULD BE FAIRLY SIMILAR TO WHAT WE
HAVE SEEN LATELY WITH HIGHS INTO THE LOW TO MID 80S. SAME CAN BE SAID
FOR LOWS TONIGHT WITH READINGS GENERALLY AROUND 70.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 418 AM EDT TUE SEP 2 2014
THE FRONTAL BOUNDARY REFERENCED IN THE SHORT TERM WILL BE DISSOLVING
EARLY IN THE LONG TERM PERIOD...BUT THERE SHOULD STILL BE DRY AIR IN
PLACE WEDNESDAY NIGHT...ESPECIALLY ALOFT. IF ANY CONVECTIVE PRECIP
CAN DEVELOP OFF OF LOW LEVEL MOISTURE ON WEDNESDAY AFTERNOON...IT
SHOULD DIE OUT BY NIGHT AS HEATING IS LOST AND SUPPORT ALOFT WILL
LIKELY BE LACKING.
DEEPER MOISTURE WILL MAKE A COMEBACK LATE IN THE WEEK AND MAY FUEL
A RESURGENCE OF SHOWERS AND THUNDERSTORMS...BUT A SUBTROPICAL RIDGE
ALOFT OVER THE SE CONUS WILL HELP TO KEEP COVERAGE LIMITED FOR A
WHILE. THE RIDGE WILL WEAKEN AND GET SUPPRESSED BY A BROAD TROUGH
DROPPING SE INTO THE NE CONUS DURING THE WEEKEND. THIS WILL ALLOW A
COLD FRONT TO MOVE INTO OUR REGION FROM THE NW. THE SCENARIO WILL
ALLOW AN INCREASE IN PRECIP COVERAGE...WITH A PEAK EXPECTED ON
SATURDAY. EVEN THOUGH THE FRONT SHOULD PASS BY SUNDAY...THE MODELS
STILL LEAVE SOME QUESTION AS TO HOW EFFECTIVE THE FRONT WILL BE AT
BRINGING IN A DRIER AIR MASS. HAVE HELD ONTO LOW POPS IN THE
AFTERNOON AND EVENING ON SUNDAY AND MONDAY...ESPECIALLY IN OUR SE
COUNTIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 156 PM EDT TUE SEP 2 2014
EASTERN KENTUCKY IS PRIMED FOR THUNDERSTORMS AS MOIST AND UNSTABLE
CONDITIONS ARE PREVALENT ACROSS THE AREA. THERE IS AN OLD OUTFLOW
BOUNDARY BISECTING THE AREA WHICH WE ARE WATCHING AS A FOCAL POINT
FOR CONVECTIVE INITIATION AND THERE IS ALSO A FRONT WHICH IS MOVING
TOWARD THE AREA FROM THE NORTHWEST WITH LOTS OF PREFRONTAL CONVECTION
OUT AHEAD OF IT. MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES
THIS AFTERNOON AND EVENING EXCEPT FOR IN THE VICINITY OF THE
THUNDERSTORMS AND RAIN SHOWERS. PUT SOME TEMPO CONDITIONS IN THE TAF
AS THE BEST ESTIMATE AS TO WHEN THUNDERSTORMS ARE MOST LIKELY AFFECT
THEM. EXPECT SOME VLIFR TO FORM AT THE TAF STATIONS AS WELL AS THE
VALLEYS LATER THIS EVENING AS THE CONVECTION MOVES OFF TO THE SOUTH
AND EAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
948 AM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 948 AM EDT TUE SEP 2 2014
THE FORECAST FOR THIS AFTERNOON HAS BECOME COMPLICATED BY THE
REMNANTS OF AN MCS OVER THE OHIO VALLEY AND THE OUTFLOW BOUNDARY
WHICH IS CURRENTLY MOVING INTO THE BLUEGRASS. CURRENT THINKING IS
THAT THE OUTFLOW BOUNDARY WILL GENERALLY WEAKEN AS IT CONTINUES
MOVING TO THE SOUTHEAST. THIS SHOULD BE TEMPORARY AND WILL THEN BE
THE FOCUS OF DEVELOPMENT LATER IN THE AFTERNOON. SO PRETTY MUCH GOING
WITH TWO PRONGS. THE FIRST BEING REDEVELOPMENT WITH THE OUTFLOW
BOUNDARY AND THE SECOND BEING THE PREFRONTAL ACTIVITY. THE SEVERE
THREAT TODAY WILL BE EFFECTED BY HOW MUCH DEBRIS CLOUD IS ABLE TO
MOVE INTO THE AREA. THE LOW LEVEL INSTABILITY WILL BE EFFECTED BY
EFFECTED BY THE CLOUDS. THE LATEST NAM BUFFER HAS REALLY BACKED OFF
FROM YESTERDAY WITH HALF THE CAPE THAN WHAT WAS FORECAST YESTERDAY.
ALSO MISSING IS THE DRY AIR POCKETS ALOFT WHICH WOULD HAVE BEEN
HELPFUL FOR WET MICROBURSTS TO OCCUR. CAN NOT RULE OUT SEVERE
THUNDERSTORMS...HOWEVER THE CHANCES HAVE GONE DOWN. MOST LIKELY WILL
STILL SEE A COUPLE OF SEVERE STORMS WITH THIS SYSTEM. UPDATED THE
FORECAST TO REFLECT THE CURRENT CONDITIONS AND MODEL TRENDS.
UPDATE ISSUED AT 649 AM EDT TUE SEP 2 2014
NO SIGNIFICANT CHANGES MADE THIS MORNING. LINE OF SHOWERS AND STORMS
EXTENDS FROM CINCINNATI SOUTHWEST TO THE NORTHWEST SIDE OF
LOUISVILLE. THIS LINE CONTINUES TO SLOWLY WEAKEN AS IT MOVES EAST. IF
IT WERE TO HOLD TOGETHER...LOOKS LIKE IT MAY WORK INTO THE BLUEGRASS
COUNTIES AFTER 13Z. HOWEVER...GIVEN THE TREND THIS SEEMS UNLIKELY AND
AT BEST PERHAPS AN ISOLATED SHOWER CAN HOLD TOGETHER. MAIN CONCERN
CONTINUES TO BE LATER TODAY...PRIMARILY AFTER 2 PM AS OUTFLOW FROM
THIS MORNINGS CONVECTION REDEVELOPS SHOWERS AND STORMS. NOT SURE THE
COVERAGE WILL BE ALL THAT GREAT AFTER LOOKING AT THE LATEST HRRR AND
NEW 06Z MAV GUIDANCE. BOTH OF THESE MODELS HAVE BACKED OFF
SIGNIFICANTLY ON THE CHANCES OF RAIN TODAY. HOWEVER...GOING TO STAY
THE COURSE AS THE TROUGH IS STILL FAIRLY DEFINED AND OUTFLOW HAS
ALREADY DEFINED A BOUNDARY FOR NEW CONVECTION TO DEVELOP.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT TUE SEP 2 2014
PRESENTLY...A SHORTWAVE TROUGH IS PUSHING INTO THE OHIO RIVER VALLEY
REGION. AN MCS DEVELOPED YESTERDAY EVENING HEAD OF THIS TROUGH AND
IS NOW MARCHING EASTWARD INTO CENTRAL/SOUTHERN INDIANA...STRETCHING
BACK TO THE SOUTHWEST ACROSS SOUTHERN ILLINOIS. IR SATELLITE HAS
SHOWN SOME WARMING WITH THE CLOUD TOPS OVER THE PAST HOUR OR
TWO...INDICATING THAT THIS MCS MAY ALREADY BE ON THE DECLINE. IN
FACT...THE HRRR SUPPORTS THE IDEA OF A DYING MCS AS IT TRIES TO PUSH
INTO CENTRAL KENTUCKY TOWARDS DAYBREAK. CANNOT RULE OUT A FEW SHOWERS
PUSHING INTO THE BLUEGRASS SHORTLY AFTER 8 AM...BUT ANTICIPATE MORE
OF THE ACTION WITH THE SHORTWAVE TROUGH WILL COME LATER THIS
AFTERNOON AS WE GENERATE SOME INSTABILITY. WITH THIS IN MIND...PLAN
TO BACK OFF THE POPS THROUGH MIDDAY WITH JUST SOME ISOLATED SHOWERS
FOR AREAS NORTH OF I-64. OUTFLOW FROM THE DYING MCS WILL BE PUSHING
ACROSS EASTERN KENTUCKY EARLY THIS AFTERNOON...AND COULD KICK START
THE CONVECTION AS IT ENCOUNTERS SOME DECENT INSTABILITY. THE FORCING
ALOFT SHOULD ALLOW FOR FAIRLY GOOD SHOWER AND THUNDERSTORM COVERAGE
BY MID TO LATE AFTERNOON. WITH BULK SHEAR VALUES OF 30-40KTS THIS
AFTERNOON...A SEVERE THREAT WOULD EXIST AS THUNDERSTORMS COULD PUT
OUT SOME DAMAGING WIND GUSTS. THE SHEAR PROFILES WEAKEN BY MID
EVENING AND THE LOSS OF DAYTIME INSTABILITY SHOULD YIELD WEAKENING
STORMS AFTER 6 PM. HOWEVER...A FEW GUSTY WINDS MAY STILL BE POSSIBLE
THROUGH 8 OR 9 PM.
THE SHORTWAVE TROUGH WILL STALL A COLD FRONT ACROSS SOUTHERN
KENTUCKY BY LATE THIS EVENING. GIVEN THE PRESENCE OF THIS
BOUNDARY...AND PLENTY OF MOISTURE...IT MAY BE POSSIBLE TO SEE
ISOLATED SHOWERS THROUGH THE NIGHT ACROSS THE SOUTHERN HALF OF
KENTUCKY. THIS BOUNDARY WILL LINGER AROUND INTO WEDNESDAY AND WITH
INSTABILITY AGAIN RAMPING UP DURING THE AFTERNOON...WE COULD BE
LOOKING AT A FEW MORE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. HOWEVER...BY WEDNESDAY...VERY LITTLE SHEAR IS
PRESENT...SO WE SHOULD SEE MORE ORDINARY THUNDERSTORMS WITH NO SEVERE
THREAT.
TEMPERATURES OVER THE NEXT 2 DAYS SHOULD BE FAIRLY SIMILAR TO WHAT WE
HAVE SEEN LATELY WITH HIGHS INTO THE LOW TO MID 80S. SAME CAN BE SAID
FOR LOWS TONIGHT WITH READINGS GENERALLY AROUND 70.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 418 AM EDT TUE SEP 2 2014
THE FRONTAL BOUNDARY REFERENCED IN THE SHORT TERM WILL BE DISSOLVING
EARLY IN THE LONG TERM PERIOD...BUT THERE SHOULD STILL BE DRY AIR IN
PLACE WEDNESDAY NIGHT...ESPECIALLY ALOFT. IF ANY CONVECTIVE PRECIP
CAN DEVELOP OFF OF LOW LEVEL MOISTURE ON WEDNESDAY AFTERNOON...IT
SHOULD DIE OUT BY NIGHT AS HEATING IS LOST AND SUPPORT ALOFT WILL
LIKELY BE LACKING.
DEEPER MOISTURE WILL MAKE A COMEBACK LATE IN THE WEEK AND MAY FUEL
A RESURGENCE OF SHOWERS AND THUNDERSTORMS...BUT A SUBTROPICAL RIDGE
ALOFT OVER THE SE CONUS WILL HELP TO KEEP COVERAGE LIMITED FOR A
WHILE. THE RIDGE WILL WEAKEN AND GET SUPPRESSED BY A BROAD TROUGH
DROPPING SE INTO THE NE CONUS DURING THE WEEKEND. THIS WILL ALLOW A
COLD FRONT TO MOVE INTO OUR REGION FROM THE NW. THE SCENARIO WILL
ALLOW AN INCREASE IN PRECIP COVERAGE...WITH A PEAK EXPECTED ON
SATURDAY. EVEN THOUGH THE FRONT SHOULD PASS BY SUNDAY...THE MODELS
STILL LEAVE SOME QUESTION AS TO HOW EFFECTIVE THE FRONT WILL BE AT
BRINGING IN A DRIER AIR MASS. HAVE HELD ONTO LOW POPS IN THE
AFTERNOON AND EVENING ON SUNDAY AND MONDAY...ESPECIALLY IN OUR SE
COUNTIES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 649 AM EDT TUE SEP 2 2014
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES OVER THE NEXT 24
TO 36 HOURS. A COLD FRONT WILL DROP SOUTH INTO EASTERN KENTUCKY
TODAY AND COULD SPAWN SCATTERED TO NUMEROUS THUNDERSTORMS THIS
AFTERNOON. PLAN TO STICK WITH THE VCTS THIS AFTERNOON AS
TIMING...COVERAGE...AND UNCERTAINTY ARE TOO GREAT TO GO WITH A
THUNDERSTORM PREVAILING GROUP. ACTIVITY SHOULD WANE BY MID TO LATE
EVENING WITH A QUIET NIGHT EXPECTED TONIGHT. HOWEVER...AS SKIES CLEAR
AND CALM WINDS...WE SHOULD SET THE STAGE FOR BETTER FOG PRODUCTION
TONIGHT...ESPECIALLY IF WE GET ANY RAIN TODAY. THUS...WILL TAKE
AIRPORTS BELOW MINIMUMS LATE TONIGHT WITH THE FOG.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
649 AM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 649 AM EDT TUE SEP 2 2014
NO SIGNIFICANT CHANGES MADE THIS MORNING. LINE OF SHOWERS AND STORMS
EXTENDS FROM CINCINNATI SOUTHWEST TO THE NORTHWEST SIDE OF
LOUISVILLE. THIS LINE CONTINUES TO SLOWLY WEAKEN AS IT MOVES EAST. IF
IT WERE TO HOLD TOGETHER...LOOKS LIKE IT MAY WORK INTO THE BLUEGRASS
COUNTIES AFTER 13Z. HOWEVER...GIVEN THE TREND THIS SEEMS UNLIKELY AND
AT BEST PERHAPS AN ISOLATED SHOWER CAN HOLD TOGETHER. MAIN CONCERN
CONTINUES TO BE LATER TODAY...PRIMARILY AFTER 2 PM AS OUTFLOW FROM
THIS MORNINGS CONVECTION REDEVELOPS SHOWERS AND STORMS. NOT SURE THE
COVERAGE WILL BE ALL THAT GREAT AFTER LOOKING AT THE LATEST HRRR AND
NEW 06Z MAV GUIDANCE. BOTH OF THESE MODELS HAVE BACKED OFF
SIGNIFICANTLY ON THE CHANCES OF RAIN TODAY. HOWEVER...GOING TO STAY
THE COURSE AS THE TROUGH IS STILL FAIRLY DEFINED AND OUTFLOW HAS
ALREADY DEFINED A BOUNDARY FOR NEW CONVECTION TO DEVELOP.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT TUE SEP 2 2014
PRESENTLY...A SHORTWAVE TROUGH IS PUSHING INTO THE OHIO RIVER VALLEY
REGION. AN MCS DEVELOPED YESTERDAY EVENING HEAD OF THIS TROUGH AND
IS NOW MARCHING EASTWARD INTO CENTRAL/SOUTHERN INDIANA...STRETCHING
BACK TO THE SOUTHWEST ACROSS SOUTHERN ILLINOIS. IR SATELLITE HAS
SHOWN SOME WARMING WITH THE CLOUD TOPS OVER THE PAST HOUR OR
TWO...INDICATING THAT THIS MCS MAY ALREADY BE ON THE DECLINE. IN
FACT...THE HRRR SUPPORTS THE IDEA OF A DYING MCS AS IT TRIES TO PUSH
INTO CENTRAL KENTUCKY TOWARDS DAYBREAK. CANNOT RULE OUT A FEW SHOWERS
PUSHING INTO THE BLUEGRASS SHORTLY AFTER 8 AM...BUT ANTICIPATE MORE
OF THE ACTION WITH THE SHORTWAVE TROUGH WILL COME LATER THIS
AFTERNOON AS WE GENERATE SOME INSTABILITY. WITH THIS IN MIND...PLAN
TO BACK OFF THE POPS THROUGH MIDDAY WITH JUST SOME ISOLATED SHOWERS
FOR AREAS NORTH OF I-64. OUTFLOW FROM THE DYING MCS WILL BE PUSHING
ACROSS EASTERN KENTUCKY EARLY THIS AFTERNOON...AND COULD KICK START
THE CONVECTION AS IT ENCOUNTERS SOME DECENT INSTABILITY. THE FORCING
ALOFT SHOULD ALLOW FOR FAIRLY GOOD SHOWER AND THUNDERSTORM COVERAGE
BY MID TO LATE AFTERNOON. WITH BULK SHEAR VALUES OF 30-40KTS THIS
AFTERNOON...A SEVERE THREAT WOULD EXIST AS THUNDERSTORMS COULD PUT
OUT SOME DAMAGING WIND GUSTS. THE SHEAR PROFILES WEAKEN BY MID
EVENING AND THE LOSS OF DAYTIME INSTABILITY SHOULD YIELD WEAKENING
STORMS AFTER 6 PM. HOWEVER...A FEW GUSTY WINDS MAY STILL BE POSSIBLE
THROUGH 8 OR 9 PM.
THE SHORTWAVE TROUGH WILL STALL A COLD FRONT ACROSS SOUTHERN
KENTUCKY BY LATE THIS EVENING. GIVEN THE PRESENCE OF THIS
BOUNDARY...AND PLENTY OF MOISTURE...IT MAY BE POSSIBLE TO SEE
ISOLATED SHOWERS THROUGH THE NIGHT ACROSS THE SOUTHERN HALF OF
KENTUCKY. THIS BOUNDARY WILL LINGER AROUND INTO WEDNESDAY AND WITH
INSTABILITY AGAIN RAMPING UP DURING THE AFTERNOON...WE COULD BE
LOOKING AT A FEW MORE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. HOWEVER...BY WEDNESDAY...VERY LITTLE SHEAR IS
PRESENT...SO WE SHOULD SEE MORE ORDINARY THUNDERSTORMS WITH NO SEVERE
THREAT.
TEMPERATURES OVER THE NEXT 2 DAYS SHOULD BE FAIRLY SIMILAR TO WHAT WE
HAVE SEEN LATELY WITH HIGHS INTO THE LOW TO MID 80S. SAME CAN BE SAID
FOR LOWS TONIGHT WITH READINGS GENERALLY AROUND 70.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 418 AM EDT TUE SEP 2 2014
THE FRONTAL BOUNDARY REFERENCED IN THE SHORT TERM WILL BE DISSOLVING
EARLY IN THE LONG TERM PERIOD...BUT THERE SHOULD STILL BE DRY AIR IN
PLACE WEDNESDAY NIGHT...ESPECIALLY ALOFT. IF ANY CONVECTIVE PRECIP
CAN DEVELOP OFF OF LOW LEVEL MOISTURE ON WEDNESDAY AFTERNOON...IT
SHOULD DIE OUT BY NIGHT AS HEATING IS LOST AND SUPPORT ALOFT WILL
LIKELY BE LACKING.
DEEPER MOISTURE WILL MAKE A COMEBACK LATE IN THE WEEK AND MAY FUEL
A RESURGENCE OF SHOWERS AND THUNDERSTORMS...BUT A SUBTROPICAL RIDGE
ALOFT OVER THE SE CONUS WILL HELP TO KEEP COVERAGE LIMITED FOR A
WHILE. THE RIDGE WILL WEAKEN AND GET SUPPRESSED BY A BROAD TROUGH
DROPPING SE INTO THE NE CONUS DURING THE WEEKEND. THIS WILL ALLOW A
COLD FRONT TO MOVE INTO OUR REGION FROM THE NW. THE SCENARIO WILL
ALLOW AN INCREASE IN PRECIP COVERAGE...WITH A PEAK EXPECTED ON
SATURDAY. EVEN THOUGH THE FRONT SHOULD PASS BY SUNDAY...THE MODELS
STILL LEAVE SOME QUESTION AS TO HOW EFFECTIVE THE FRONT WILL BE AT
BRINGING IN A DRIER AIR MASS. HAVE HELD ONTO LOW POPS IN THE
AFTERNOON AND EVENING ON SUNDAY AND MONDAY...ESPECIALLY IN OUR SE
COUNTIES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 649 AM EDT TUE SEP 2 2014
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES OVER THE NEXT 24
TO 36 HOURS. A COLD FRONT WILL DROP SOUTH INTO EASTERN KENTUCKY
TODAY AND COULD SPAWN SCATTERED TO NUMEROUS THUNDERSTORMS THIS
AFTERNOON. PLAN TO STICK WITH THE VCTS THIS AFTERNOON AS
TIMING...COVERAGE...AND UNCERTAINTY ARE TOO GREAT TO GO WITH A
THUNDERSTORM PREVAILING GROUP. ACTIVITY SHOULD WANE BY MID TO LATE
EVENING WITH A QUIET NIGHT EXPECTED TONIGHT. HOWEVER...AS SKIES CLEAR
AND CALM WINDS...WE SHOULD SET THE STAGE FOR BETTER FOG PRODUCTION
TONIGHT...ESPECIALLY IF WE GET ANY RAIN TODAY. THUS...WILL TAKE
AIRPORTS BELOW MINIMUMS LATE TONIGHT WITH THE FOG.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
418 AM EDT TUE SEP 2 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT TUE SEP 2 2014
PRESENTLY...A SHORTWAVE TROUGH IS PUSHING INTO THE OHIO RIVER VALLEY
REGION. AN MCS DEVELOPED YESTERDAY EVENING HEAD OF THIS TROUGH AND
IS NOW MARCHING EASTWARD INTO CENTRAL/SOUTHERN INDIANA...STRETCHING
BACK TO THE SOUTHWEST ACROSS SOUTHERN ILLINOIS. IR SATELLITE HAS
SHOWN SOME WARMING WITH THE CLOUD TOPS OVER THE PAST HOUR OR
TWO...INDICATING THAT THIS MCS MAY ALREADY BE ON THE DECLINE. IN
FACT...THE HRRR SUPPORTS THE IDEA OF A DYING MCS AS IT TRIES TO PUSH
INTO CENTRAL KENTUCKY TOWARDS DAYBREAK. CANNOT RULE OUT A FEW SHOWERS
PUSHING INTO THE BLUEGRASS SHORTLY AFTER 8 AM...BUT ANTICIPATE MORE
OF THE ACTION WITH THE SHORTWAVE TROUGH WILL COME LATER THIS
AFTERNOON AS WE GENERATE SOME INSTABILITY. WITH THIS IN MIND...PLAN
TO BACK OFF THE POPS THROUGH MIDDAY WITH JUST SOME ISOLATED SHOWERS
FOR AREAS NORTH OF I-64. OUTFLOW FROM THE DYING MCS WILL BE PUSHING
ACROSS EASTERN KENTUCKY EARLY THIS AFTERNOON...AND COULD KICK START
THE CONVECTION AS IT ENCOUNTERS SOME DECENT INSTABILITY. THE FORCING
ALOFT SHOULD ALLOW FOR FAIRLY GOOD SHOWER AND THUNDERSTORM COVERAGE
BY MID TO LATE AFTERNOON. WITH BULK SHEAR VALUES OF 30-40KTS THIS
AFTERNOON...A SEVERE THREAT WOULD EXIST AS THUNDERSTORMS COULD PUT
OUT SOME DAMAGING WIND GUSTS. THE SHEAR PROFILES WEAKEN BY MID
EVENING AND THE LOSS OF DAYTIME INSTABILITY SHOULD YIELD WEAKENING
STORMS AFTER 6 PM. HOWEVER...A FEW GUSTY WINDS MAY STILL BE POSSIBLE
THROUGH 8 OR 9 PM.
THE SHORTWAVE TROUGH WILL STALL A COLD FRONT ACROSS SOUTHERN
KENTUCKY BY LATE THIS EVENING. GIVEN THE PRESENCE OF THIS
BOUNDARY...AND PLENTY OF MOISTURE...IT MAY BE POSSIBLE TO SEE
ISOLATED SHOWERS THROUGH THE NIGHT ACROSS THE SOUTHERN HALF OF
KENTUCKY. THIS BOUNDARY WILL LINGER AROUND INTO WEDNESDAY AND WITH
INSTABILITY AGAIN RAMPING UP DURING THE AFTERNOON...WE COULD BE
LOOKING AT A FEW MORE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. HOWEVER...BY WEDNESDAY...VERY LITTLE SHEAR IS
PRESENT...SO WE SHOULD SEE MORE ORDINARY THUNDERSTORMS WITH NO SEVERE
THREAT.
TEMPERATURES OVER THE NEXT 2 DAYS SHOULD BE FAIRLY SIMILAR TO WHAT WE
HAVE SEEN LATELY WITH HIGHS INTO THE LOW TO MID 80S. SAME CAN BE SAID
FOR LOWS TONIGHT WITH READINGS GENERALLY AROUND 70.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 418 AM EDT TUE SEP 2 2014
THE FRONTAL BOUNDARY REFERENCED IN THE SHORT TERM WILL BE DISSOLVING
EARLY IN THE LONG TERM PERIOD...BUT THERE SHOULD STILL BE DRY AIR IN
PLACE WEDNESDAY NIGHT...ESPECIALLY ALOFT. IF ANY CONVECTIVE PRECIP
CAN DEVELOP OFF OF LOW LEVEL MOISTURE ON WEDNESDAY AFTERNOON...IT
SHOULD DIE OUT BY NIGHT AS HEATING IS LOST AND SUPPORT ALOFT WILL
LIKELY BE LACKING.
DEEPER MOISTURE WILL MAKE A COMEBACK LATE IN THE WEEK AND MAY FUEL
A RESURGENCE OF SHOWERS AND THUNDERSTORMS...BUT A SUBTROPICAL RIDGE
ALOFT OVER THE SE CONUS WILL HELP TO KEEP COVERAGE LIMITED FOR A
WHILE. THE RIDGE WILL WEAKEN AND GET SUPPRESSED BY A BROAD TROUGH
DROPPING SE INTO THE NE CONUS DURING THE WEEKEND. THIS WILL ALLOW A
COLD FRONT TO MOVE INTO OUR REGION FROM THE NW. THE SCENARIO WILL
ALLOW AN INCREASE IN PRECIP COVERAGE...WITH A PEAK EXPECTED ON
SATURDAY. EVEN THOUGH THE FRONT SHOULD PASS BY SUNDAY...THE MODELS
STILL LEAVE SOME QUESTION AS TO HOW EFFECTIVE THE FRONT WILL BE AT
BRINGING IN A DRIER AIR MASS. HAVE HELD ONTO LOW POPS IN THE
AFTERNOON AND EVENING ON SUNDAY AND MONDAY...ESPECIALLY IN OUR SE
COUNTIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 207 AM EDT TUE SEP 2 2014
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES OVER THE NEXT 24
TO 36 HOURS. A WEAK COLD FRONT WILL DROP SOUTH INTO EASTERN KENTUCKY
TODAY AND COULD SPAWN SCATTERED TO NUMEROUS THUNDERSTORMS. PLAN TO
STICK WITH THE VCTS THIS AFTERNOON AS TIMING AND UNCERTAINTY ARE TOO
GREAT TO GO WITH A THUNDERSTORM PREVAILING GROUP. ACTIVITY SHOULD
WANE BY MID TO LATE EVENING WITH A QUIET NIGHT EXPECTED TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
330 AM EDT TUE SEP 2 2014
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT TUE SEP 2 2014
PRESENTLY...A SHORTWAVE TROUGH IS PUSHING INTO THE OHIO RIVER VALLEY
REGION. AN MCS DEVELOPED YESTERDAY EVENING HEAD OF THIS TROUGH AND
IS NOW MARCHING EASTWARD INTO CENTRAL/SOUTHERN INDIANA...STRETCHING
BACK TO THE SOUTHWEST ACROSS SOUTHERN ILLINOIS. IR SATELLITE HAS
SHOWN SOME WARMING WITH THE CLOUD TOPS OVER THE PAST HOUR OR
TWO...INDICATING THAT THIS MCS MAY ALREADY BE ON THE DECLINE. IN
FACT...THE HRRR SUPPORTS THE IDEA OF A DYING MCS AS IT TRIES TO PUSH
INTO CENTRAL KENTUCKY TOWARDS DAYBREAK. CANNOT RULE OUT A FEW SHOWERS
PUSHING INTO THE BLUEGRASS SHORTLY AFTER 8 AM...BUT ANTICIPATE MORE
OF THE ACTION WITH THE SHORTWAVE TROUGH WILL COME LATER THIS
AFTERNOON AS WE GENERATE SOME INSTABILITY. WITH THIS IN MIND...PLAN
TO BACK OFF THE POPS THROUGH MIDDAY WITH JUST SOME ISOLATED SHOWERS
FOR AREAS NORTH OF I-64. OUTFLOW FROM THE DYING MCS WILL BE PUSHING
ACROSS EASTERN KENTUCKY EARLY THIS AFTERNOON...AND COULD KICK START
THE CONVECTION AS IT ENCOUNTERS SOME DECENT INSTABILITY. THE FORCING
ALOFT SHOULD ALLOW FOR FAIRLY GOOD SHOWER AND THUNDERSTORM COVERAGE
BY MID TO LATE AFTERNOON. WITH BULK SHEAR VALUES OF 30-40KTS THIS
AFTERNOON...A SEVERE THREAT WOULD EXIST AS THUNDERSTORMS COULD PUT
OUT SOME DAMAGING WIND GUSTS. THE SHEAR PROFILES WEAKEN BY MID
EVENING AND THE LOSS OF DAYTIME INSTABILITY SHOULD YIELD WEAKENING
STORMS AFTER 6 PM. HOWEVER...A FEW GUSTY WINDS MAY STILL BE POSSIBLE
THROUGH 8 OR 9 PM.
THE SHORTWAVE TROUGH WILL STALL A COLD FRONT ACROSS SOUTHERN
KENTUCKY BY LATE THIS EVENING. GIVEN THE PRESENCE OF THIS
BOUNDARY...AND PLENTY OF MOISTURE...IT MAY BE POSSIBLE TO SEE
ISOLATED SHOWERS THROUGH THE NIGHT ACROSS THE SOUTHERN HALF OF
KENTUCKY. THIS BOUNDARY WILL LINGER AROUND INTO WEDNESDAY AND WITH
INSTABILITY AGAIN RAMPING UP DURING THE AFTERNOON...WE COULD BE
LOOKING AT A FEW MORE ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. HOWEVER...BY WEDNESDAY...VERY LITTLE SHEAR IS
PRESENT...SO WE SHOULD SEE MORE ORDINARY THUNDERSTORMS WITH NO SEVERE
THREAT.
TEMPERATURES OVER THE NEXT 2 DAYS SHOULD BE FAIRLY SIMILAR TO WHAT WE
HAVE SEEN LATELY WITH HIGHS INTO THE LOW TO MID 80S. SAME CAN BE SAID
FOR LOWS TONIGHT WITH READINGS GENERALLY AROUND 70.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 AM EDT TUE SEP 2 2014
LONG TERM DISCUSSION WILL FOLLOW SHORTLY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 207 AM EDT TUE SEP 2 2014
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES OVER THE NEXT 24
TO 36 HOURS. A WEAK COLD FRONT WILL DROP SOUTH INTO EASTERN KENTUCKY
TODAY AND COULD SPAWN SCATTERED TO NUMEROUS THUNDERSTORMS. PLAN TO
STICK WITH THE VCTS THIS AFTERNOON AS TIMING AND UNCERTAINTY ARE TOO
GREAT TO GO WITH A THUNDERSTORM PREVAILING GROUP. ACTIVITY SHOULD
WANE BY MID TO LATE EVENING WITH A QUIET NIGHT EXPECTED TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
207 AM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 207 AM EDT TUE SEP 2 2014
UPDATED TO REMOVE POPS FOR MOST AREAS THROUGH THE REMAINDER OF THE
NIGHT. THE MCS TO OUR WEST WILL APPROACH THE BLUEGRASS TOWARDS 8
AM...BUT MOST AREAS SHOULD STAY DRY UNTIL THEN. THIS MCS IS EXPECTED
TO DECAY THROUGH THE MORNING HOURS AND REALLY NOT MAKE IT VERY FAR
INTO EASTERN KENTUCKY IF IT MAKES IT AT ALL. MAY NEED TO WATCH FOR
REDEVELOPMENT ALONG THE OUTFLOW FROM THIS SYSTEM LATER ON TOWARDS
MIDDAY OR THE AFTERNOON. NO OTHER CHANGES PLANNED AT THIS TIME.
UPDATE ISSUED AT 1045 PM EDT MON SEP 1 2014
ISOLATED SHOWERS CONTINUE TO AFFECT NORTHERN KY...INCLUDING THE
NORTHERN PART OF THE JACKSON FORECAST AREA. THE SHOWERS HAVE SHOWN A
DECREASING TREND...AND THE TOTAL LIGHTNING DATA INDICATES THERE IS NO
LONGER ANY LIGHTNING IN KY. CONVECTION CONTINUES TO DEVELOP ACROSS MO
AND CENTRAL IL. BASED ON CURRENT TRENDS AND THE LATEST HRRR DATA THIS
COULD IMPACT OUR AREA BEGINNING SOMETIME NEAR OF AFTER 12Z. HOURLY
NDFD DATA HAS BEEN UPDATED FOR LATEST OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 751 PM EDT MON SEP 1 2014
ISOLATED THUNDERSTORMS CONTINUE TO AFFECT THE NORTHERN THIRD OF
KY...INCLUDING THE NORTHERN PART OF THE JACKSON FORECAST AREA. WITH
LOSS OF DAYTIME HEATING EXPECT THE ISOLATED CONVECTION TO CONTINUE TO
WANE. HOWEVER A SHORT WAVE MOVING INTO MO IS RESULTING IN AN
INCREASE IN SHOWERS AND THUNDERSTORMS AHEAD OF THE SURFACE COLD FRONT
THERE...AND THE REMNANTS OF THIS CONVECTION MAY AFFECT THE NORTHERN
PARTS OF THE FORECAST AREA LATE TONIGHT OR EARLY TUESDAY MORNING. THIS
IDEA IS SUPPORTED BY THE LATEST HRRR AND THE 18Z NAM AND GFS. HAVE
UPDATED NDFD FOR LATEST OBSERVATIONAL TRENDS AND WILL BE MAKING
ADDITIONAL ADJUSTMENTS TO HOURLY WEATHER GRIDS SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 315 PM EDT MON SEP 1 2014
A LINE OF SCATTERED SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE
ACROSS EASTERN KENTUCKY. THIS LINE IS OUT AHEAD OF THE COLD FRONT IN
THE WARM AIR. THERE IS A BIT OF CURVATURE TO THE LINE OF HEAVIEST
STORMS;...SO WILL BE WATCHING FOR SOME POTENTIALLY STRONG WIND GUSTS
AS THE LINE GOES THROUGH. THE MERCER AND LINCOLN COUNTY MESONET
SITES SAW WIND GUSTS OF 30 MPH AS THE LINE WENT THROUGH AND BATH
COUNTY SAW A GUST TO 41 MPH. CURRENT THINKING IS THE MAX GUSTS STAY
AROUND 40 MPH WITH THE STRONGEST STORMS AND MOST GUSTS WILL BE IN
THE 25 TO 35 MPH RANGE AS THE STORMS CONTINUE TO MOVE ACROSS EASTERN
KENTUCKY. THESE STORMS WILL DROP BETWEEN 0.25 TO 0.75 INCHES OF RAIN
AS IT MOVES ACROSS THE AREA. HAVE A LITTLE CONCERN FOR PARTS OF
EASTERN KENTUCKY THAT GOT HAMMERED LAST NIGHT FROM THE HEAVY
RAIN...HOWEVER THESE STORMS HAVE BEEN QUITE PROGRESSIVE AND HAVE NOT
YET SEEN ANY TRAINING OF THE ECHOES. THIS LINE SHOULD CONTINUE TO
MOVE ACROSS THE AREA AND THEN THE LEADING EDGE OF THE PREFRONTAL
PRECIPITATION WILL BE MOVING INTO THE AREA LATER TONIGHT. THE FRONT
WILL BE MOVING ACROSS THE AREA TOMORROW AND BRING WIDESPREAD SHOWERS
AND THUNDERSTORMS TO THE AREA. THERE WILL BE A SLIGHT RISK OF SEVERE
THUNDERSTORMS TOMORROW. SPC CURRENTLY HAS MOST OF EASTERN KENTUCKY
IN THE SLIGHT RISK AREA. THE MAIN THREAT WILL BE WINDS WITH A VERY
WEAK THREAT FOR MARGINALLY SEVERE HAIL. MOST LIKELY...ANY HAIL WILL
STAY IN THE 0.5 TO 0.75 INCH RANGE. THE PRECIPITATION WILL DROP OFF
FAIRLY QUICKLY BEHIND THE FRONT. THE MODELS ARE IN VERY GOOD
AGREEMENT WITH THE TIMING. WENT WITH THE MODEL BLEND FOR THE
TEMPERATURES WITH JUST SOME ADJUSTMENTS DUE TO ELEVATION.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 315 PM EDT MON SEP 1 2014
THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE
AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE
SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A
WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE
NORTHERN PLAINS. THE MODELS HAVE THE RIDGE BREAKING DOWN
CONSISTENTLY TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING
UP BENEATH IT ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF. AS THE
TROUGH EVOLVES AND STRENGTHENS...IT WILL EJECT OUT OF THE PLAINS
WEDNESDAY NIGHT AND THURSDAY...AND PUSH ACROSS THE GREAT LAKES AND
OHIO VALLEY REGIONS. THE COLD FRONT TRAILING FROM THIS UPPER LOW
WILL END BEING OUR WEATHER MAKER FOR THE UPCOMING WEEKEND. THE FRONT
IS EXPECTED TO INTERACT WITH MOISTURE COMING OFF THE GULF OF MEXICO
ON SOUTHWESTERLY WINDS. THE FRONT WILL HAVE A DIFFICULT TIME MOVING
EASTWARD...HOWEVER...AS THE RIDGE DIGS IN A BIT JUST OFF THE
SOUTHEAST COAST AND FLOW ALOFT BECOMES MORE ZONAL. THERE WILL BE A
GOOD CHANCE OF RAIN FRIDAY MORNING THROUGH SUNDAY MORNING...AS LIFT
AND MOISTURE ALONG THE SLUGGISH FRONT SET OFF REPEATED ROUNDS OF
SHOWERS AND STORMS. THE RAIN SHOULD FINALLY MOVE OUT OF THE AREA
SUNDAY EVENING...AS THE FRONT FINALLY MOVES OUT OF THE AREA.
TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH
HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S WEDNESDAY THROUGH
FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION
BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW
NORMAL VALUES SATURDAY THROUGH MONDAY. HIGHS ON FRIDAY WILL BE
CLOSER TO NORMAL AS THE FRONT WILL STILL BE TO OUR WEST. ON SATURDAY
AND SUNDAY...THE POSITIONING OF THE FRONT WILL ALLOW FOR SOME COOLER
AND DRIER AIR TO FILTER INTO THE AREA. HIGHS ON SATURDAY SHOULD BE
CLOSE TO NORMAL...AS THE BULK OF COOL AIR SHOULD STILL BE TRAPPED
NORTH OF THE OHIO RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE
SHIFTED TO THE NORTH...TEMPERATURES WILL BE QUITE COOL...WITH
READINGS PEAKING IN THE MID TO UPPER 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 207 AM EDT TUE SEP 2 2014
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES OVER THE NEXT 24
TO 36 HOURS. A WEAK COLD FRONT WILL DROP SOUTH INTO EASTERN KENTUCKY
TODAY AND COULD SPAWN SCATTERED TO NUMEROUS THUNDERSTORMS. PLAN TO
STICK WITH THE VCTS THIS AFTERNOON AS TIMING AND UNCERTAINTY ARE TOO
GREAT TO GO WITH A THUNDERSTORM PREVAILING GROUP. ACTIVITY SHOULD
WANE BY MID TO LATE EVENING WITH A QUIET NIGHT EXPECTED TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...JJ
LONG TERM...AR
AVIATION...KAS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1045 AM EDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 1044 AM EDT TUE SEP 2 2014
LIMITED CHANGES TO THE GOING FORECAST. MAIN CHANGE WAS TO THE
THICKNESS OF THE MID-HIGH CLOUDS STREAMING NORTHEAST ACROSS THE
AREA THIS MORNING AND HAVE BUMPED THE FORECAST UP TO MOSTLY CLOUDY
OVER THE CENTRAL U.P. AS THIS MOVES THROUGH. DO HAVE SOME CONCERN ON
THE IMPACT THE CLOUDS WILL HAVE ON DIURNAL HEATING TODAY AND IN TURN
SHOWERS DEVELOPING THIS AFTERNOON. HAVE NOTICED A TREND IN THE
HIGH-RES MODELS (HRRR...NAMDNG...AND OUR LOCAL WRF-ARW) TO DEVELOP
THE SHOWERS A LITTLE FARTHER TO THE EAST (GENERALLY EASTERN
MARQUETTE/MENOMINEE COUNTIES AND EASTWARD)...AND HAVE ADJUSTED THE
POPS SLIGHTLY TOWARDS THAT IDEA. THE EASTERN U.P. STILL LOOKS TO
HAVE THE BEST CHANCES DUE TO LAKE BREEZE CONVERGENCE AND STORM
MOTION VECTORS PUSHING SHOWERS EASTWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE SEP 2 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD LOW AMPLITUDE
MID/UPPER LEVEL TROUGH THROUGH FROM THE NRN PLAINS INTO THE UPPER MS
VALLEY AND WRN GREAT LAKES WITH SEVERAL WEAK EMBEDDED SHORTWAVES.
ONE WAS LOCATED FROM SW MN INTO NW IA WHILE ANOTHER UPSTREAM SHRTWV
WAS MOVING THROUGH NORTH DAKOTA. AT THE SFC...WRLY FLOW PREVAILED
ACROSS UPPER MI BETWEEN A 987 MB LOW NEAR JAMES BAY AND A WEAK RIDGE
INTO THE CNTRL PLAINS.IR LOOP SHOWED MAINLY CLEAR SKIES ACROSS MOST
OF THE CWA BUT WITH INCREASING CLOUDS FROM MN INTO NW WI AND WRN
UPPER MI AHEAD OF THE SW MN SHRTWV.
TODAY...MOST OF THE FORCING ASSOCIATED WITH THE MN SHRTWV IS
EXPECTED TO REMAIN SOUTH OF UPPER MI. HOWEVER...THE COMBINATION OF
DAYTIME HEATING AND 850-600 MB LAPSE RATES TO NEAR 7.5C/KM AND LOW
LEVEL CONV ALONG LAKE BREEZE BOUNDARIES(ESPECIALLY OVER THE EAST)
WILL SUPPORT ISOLD/SCT SHRA BY THIS AFTERNOON. AS THE NORTH DAKOTA
SHRTWV NEAR BY MID TO LATE AFTERNOON SOME ADDITIONAL WEAK QVECTOR
CONV MAY ALSO CONTRIBUTE TO PCPN CHANCES. ALTHOUGH MLCAPE VALUES
INTO THE 400-800 J/KG RANGE WILL BE MARGINAL FOR TS...SOME ISOLD COULD
DEVELOP. WITH FREEZING HEIGHTS ONLY NEAR 9K-10K FT...SOME SMALL HAIL
MAY BE POSSIBLE.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND THE SHRTWVS EXITING
TO THE EAST...ANY PCPN SHOULD QUICKLY DIMINISH. WITH THE FAST
MID/UPPER LEVEL FLOW ACROSS THE NRN CONUS...MODELS SUGGEST THAT
ANOTHER WEAK SHRTWV COULD MOVE THROUGH THE NRN LAKES AND PRODUCE
SOME LIGHT PCPN. HOWEVER...WITH VERY LIMITED MOISTURE AND LITTLE
INSTABILITY...CONFIDENCE IN ADDITIONAL PCPN DEVELOPING WAS LOW AND NO
ADDITIONAL RAIN WAS MENTIONED.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 401 AM EDT TUE SEP 2 2014
THOUGH ACTIVE WEDNESDAY NIGHT INTO THURSDAY EVENING...THE REST OF
LONG TERM WILL BE QUIET AS HIGH PRESSURE DOMINATES FROM FRIDAY INTO
EARLY NEXT WEEK.
STARTING ON WEDNESDAY...WEAKER SHORTWAVES WORK THEIR WAY ACROSS
NORTHERN PLAINS AND TO UPPER GREAT LAKES BY LATE IN THE DAY IN A
ZONAL FLOW PATTERN ALOFT. LARGE SCALE LIFT IS PRESENT BUT THERE IS
NOT MUCH FOR A STRONGER SHORTWAVE AND ALSO OVERALL MOISTURE IS
LIMITED. BULK OF SHRA/TSRA LATER ON WEDNESDAY SHOULD STAY WEST OF
UPR MICHIGAN...MAINLY OVER CENTRAL AND SOUTHERN MINNESOTA CLOSER TO
SFC WARM FRONT AND BUILDING INSTABILITY. COULD SEE ISOLD SHRA/TSRA
OVER WESTERN LK SUPERIOR OR EVEN FAR WEST UPR MICHIGAN DUE TO
GENERAL H85-H7 WARM AIR ADVECTION AND MID-LEVEL MOISTURE ADVECTION.
TEMPS ON WEDNESDAY SHOULD PUSH INTO THE UPPER 70S OR LOWER 80S EVEN
WITH SCT-BKN MID CLOUDS IN THE AFTN.
POTENTIAL FOR PERIOD OF ACTIVE WEATHER WEDNESDAY NIGHT INTO THURSDAY
MORNING AS THE APPROACH OF A SFC LOW OVER THE NORTHERN PLAINS INCREASES
LOW-LEVEL JET /40 KTS AT H85/ INTO THE UPPER GREAT LAKES. SINCE THERE
IS NOT REALLY A STRONG SHORTWAVE MOVING THROUGH AT THAT TIME THOUGH...THINK
THAT THE BULK OF SHRA/TSRA WILL BE VCNTY OF WHERE LOW- LEVEL JET
INTERSECTS THE SFC-H85 WARM FRONT. BASED ON SFC WINDS AND DWPNTS...BEST
GUESS AT LOCATION OF THAT BOUNDARY IS FM CNTRL MN INTO WESTERN WI
WEDNESDAY NIGHT. MAX INSTABILITY BOTH IN TERMS OF MLCAPE AND ELEVATED
MUCAPE WILL BE MAXIMIZED OVER MUCH OF MINNESOTA AND INTO WISCONSIN
WITH INSTABILITY TRAILING OFF CONSIDERABLY INTO UPR MICHIGAN AND LK
MICHIGAN/LOWER MICHIGAN. MAJORITY OF MODELS INDICATE WIDESPREAD QPF
OVER UPR MICHIGAN WEDNESDAY NIGHT...BUT HAVE MY DOUBTS ON THIS AS
MOST OF THE HEAVY SHRA/TSRA COULD END UP FARTHER SOUTH ALONG WARM
FRONT AND ALSO BASED ON H85-H3 THICKNESSES WHICH...ALONG WITH FORWARD
PROPAGATING CORFIDI VECTORS...CAN BE USED TO DETERMINE GENERAL MOTION
OF AN MCS. SIMILAR TO EARLIER IN THE NIGHT...THERE IS STILL MID-LEVEL
MOISTURE ADVECTION FARTHER NORTH OF THE BOUNDARY THOUGH SO CANNOT
COMPLETELY RULE OUT SHRA/TSRA MAKING IT ACROSS UPR MICHIGAN. ANOTHER
FACTOR THAT COULD BUMP SHRA/TSRA FARTHER NORTH INTO THE CWA IS
INCREASING CAPPING THAT DEVELOPS IN THE H8-H7 LAYER OUT AHEAD OF THE
SFC LOW. AT THIS POINT THOUGH IT APPEARS THAT MAIN EXTENT OF CAPPING
WILL REMAIN BACK OVER THE CENTRAL PLAINS ON WEDNESDAY NIGHT.
GIVEN THE CONCERNS ABOUT TSRA OVERAGE...BACKED DOWN A BIT ON THE
HIGHER POPS WE HAD GOING BUT DID KEEP POPS HIGH CHANCE TO LOW END
LIKELY WITH BETTER CHANCES OVER THE WEST INITIALLY SHIFTING TO THE
EAST FOLLOWING THE TREND OF H7-H5 Q-VECTOR CONVERGENCE TIED TO
INITIAL WEAK SHORTWAVE AND ALSO WHERE THIS FORCING SYNCS UP WITH
GREATER MID-LEVEL MOISTURE TRANSPORT. TSRA INTENSITY SHOULD DIMINISH
INTO THE EAST BY LATE WED NIGHT INTO THURSDAY MORNING AS SHRA/TSRA
OUTRUN GREATER POOL OF INSTABILITY OVER MINNESOTA AND WISCONSIN.
FOR THURSDAY...RETAINED MUCH OF THE PREVIOUS FORECAST SHOWING TREND
TOWARD LOWER POPS BY LATE THURSDAY MORNING IN WAKE OF THE INITIAL
SHRA/TSRA MOVING EAST THEN POPS RAMPING BACK UP IN THE AFTN WITH
POSSIBLE ADDITIONAL SHRA/TSRA AHEAD OF APPROACHING COLD FRONT.
CAPPING SHOULD INCREASE MARKEDLY BY LATE MORNING/EARLY AFTN BASED
ON FORECAST SOUNDINGS SO THIS WILL IMPACT ADDITIONAL DEVELOPMENT OF
SHRA/TSRA. COULD GET QUITE WARM WITH EVEN JUST A LITTLE CLEARING.
MIXING TO H9 WITH SHARPER INVERSION AROUND THAT LEVEL SHOWN ON
SOUNDINGS MAY BE CONSERVATIVE BUT STILL RESULTS IN HIGHS AROUND 80
OVER MUCH OF CWA. NUDGED TEMPS UP INTO THE LOWER 80S AS A STARTING
POINT...BUT A MUGGY DAY /SFC DWPNTS 65-70/ WITH MID 80S IS CERTAINLY
POSSIBLE IN SOME AREAS. PRIMARY SHORTWAVE DRIVING THE COLD FRONT WILL
BE JUST NORTH OF MINNESOTA BY LATE THURSDAY AFTN. GIVEN THE WARM AND
HUMID AIRMASS...MLCAPES AHEAD OF THE FRONT OVER WEST HALF OF CWA
COULD PUSH OVER 2500J/KG...BUT MAIN QUESTIONS ARE HOW MUCH DEEPER
MOISTURE WILL BE AROUND AHEAD OF THE FRONT AND WILL CAPPING IN THE
H8-H7 LAYER BE TOO STRONG TO PROHIBIT SHRA/TSRA FROM DEVELOPING?
BASED ON CONSENSUS OF MODELS AND LATEST TRENDS...SEEMS THAT THERE IS
A RISK OF STORMS FORMING MID-LATE THURSDAY AFTN OVER THE WEST AND
AFFECTING REST OF CWA INTO THE EARLY EVENING AS BETTER MOISTURE IS
RE-INTRODUCED INTO THE AREA FM THE WEST/SOUTHWEST AND LIFT INCREASES
AND CAPPING DECREASES AS SHORTWAVE AND H5 SPEED MAX DRAW CLOSER. GIVEN
THE DEGREE OF INSTABILITY...IF STORMS FORM...SEVERE WEATHER POTENTIAL
IS ELEVATED AS 0-6KM SHEAR IS OVER 45 KTS AND 0-3KM SHEAR IS OVER 30
KTS. THE FORECASTED INSTABILITY...IF IT IS INDEED REALIZED...AND
SUCH SHEAR WOULD SUPPORT ROTATING/SUPERCELL TYPE STORMS AND ALSO
POTENTIAL FOR STORMS CONSOLIDATING INTO SEVERE WIND GUST PRODUCING
MCS ALONG THE COLD FRONT. A CONDITIONAL RISK ATTM...BUT CERTAINTLY
WORTH MONITORING AS WE GET CLOSER TO THIS TIME FRAME. SPC DAY3
OUTLOOK HIGHLIGHTS WI INTO WEST HALF OF UPR MICHIGAN WITH A 15 PCT
RISK FOR SEVERE /SLIGHT CATEGORICAL RISK/. WILL MENTION POTENTIAL
FOR SEVERE IN THE MORNING HAZARDOUS WEATHER OUTLOOK.
ONCE THE COLD FRONT SLIDES THROUGH ON THURSDAY NIGHT...ANY LINGERING
SHRA/TSRA WILL QUICKLY COME TO AN END BY THE OVERNIGHT SOUTH AND
EAST CWA. MAIN ISSUE LATE THURSDAY NIGHT INTO FRIDAY WILL BE GUSTY
NORTHWEST WINDS ON LK SUPERIOR AS IT BECOMES UNSTABLE IN THE 1000-900MB
LAYER. MIXED LAYER WINDS ARE OVER 30 KTS SO IT COULD BE GUSTY ALONG
THE LK SUPERIOR SHORE TO BEGIN THE DAY ON FRIDAY. DUE TO PRESSURE
RISES BTWN DEPARTING LOW AND APPROACHING HIGH...EVEN HIGHER WINDS
WOULD NOT BE OUT OF QUESTION. INCREASING WAVE ACTION WOULD ALSO LEAD
TO HIGH SWIM RISK ON BEACHES FROM MARQUETTE TO GRAND MARAIS.
QUIET WEATHER FOR THE WEEKEND AS IT LOOKS NOW. HIGH PRESSURE SETTLES
OVERHEAD AND STAYS IN PLACE INTO EARLY NEXT WEEK. TEMPS AT NIGHT MAY
DIP BLO 40 DEGREES IN THE INTERIOR. DAYTIME HIGHS WILL BE SEASONABLY
COOL IN THE 60S FOR MOST AREAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 738 AM EDT TUE SEP 2 2014
EXPECT VFR CONDITIONS TO PREVAIL THIS FCST PERIOD WITH RELATIVELY
DRY LOW LEVEL AIR DOMINATING. AN APPROACHING UPPER DISTURBANCE ALONG
WITH DAYTIME HEATING AND DESTABILIZATION COULD CAUSE SOME -SHRA AT
SAW AND PERHAPS IWD THIS AFTN...BUT THE DRY LOW LEVEL AIR SHOULD
MAINTAIN PREDOMINANT VFR WX EVEN IF THE -SHRA OCCUR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT TUE SEP 2 2014
WINDS WILL BE 20 KNOTS OR LESS THROUGH MOST OF THIS FORECAST PERIOD
EXCEPT FOR THU NIGHT INTO FRI WHEN WEST TO NORTHWEST WINDS BEHIND A
STRONG COLD FRONT WILL APPROACH 30 KNOTS. THIS WILL BE THE WHEN THE
STRONGEST WINDS OCCUR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT TUE SEP 2 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE SEP 2 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD LOW AMPLITUDE
MID/UPPER LEVEL TROUGH THROUGH FROM THE NRN PLAINS INTO THE UPPER MS
VALLEY AND WRN GREAT LAKES WITH SEVERAL WEAK EMBEDDED SHORTWAVES.
ONE WAS LOCATED FROM SW MN INTO NW IA WHILE ANOTHER UPSTREAM SHRTWV
WAS MOVING THROUGH NORTH DAKOTA. AT THE SFC...WRLY FLOW PREVAILED
ACROSS UPPER MI BETWEEN A 987 MB LOW NEAR JAMES BAY AND A WEAK RIDGE
INTO THE CNTRL PLAINS.IR LOOP SHOWED MAINLY CLEAR SKIES ACROSS MOST
OF THE CWA BUT WITH INCREASING CLOUDS FROM MN INTO NW WI AND WRN
UPPER MI AHEAD OF THE SW MN SHRTWV.
TODAY...MOST OF THE FORCING ASSOCIATED WITH THE MN SHRTWV IS
EXPECTED TO REMAIN SOUTH OF UPPER MI. HOWEVER...THE COMBINATION OF
DAYTIME HEATING AND 850-600 MB LAPSE RATES TO NEAR 7.5C/KM AND LOW
LEVEL CONV ALONG LAKE BREEZE BOUNDARIES(ESPECIALLY OVER THE EAST)
WILL SUPPORT ISOLD/SCT SHRA BY THIS AFTERNOON. AS THE NORTH DAKOTA
SHRTWV NEAR BY MID TO LATE AFTERNOON SOME ADDITIONAL WEAK QVECTOR
CONV MAY ALSO CONTRIBUTE TO PCPN CHANCES. ALTHOUGH MLCAPE VALUES
INTO THE 400-800 J/KG RANGE WILL BE MARGINAL FOR TS...SOME ISOLD COULD
DEVELOP. WITH FREEZING HEIGHTS ONLY NEAR 9K-10K FT...SOME SMALL HAIL
MAY BE POSSIBLE.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND THE SHRTWVS EXITING
TO THE EAST...ANY PCPN SHOULD QUICKLY DIMINISH. WITH THE FAST
MID/UPPER LEVEL FLOW ACROSS THE NRN CONUS...MODELS SUGGEST THAT
ANOTHER WEAK SHRTWV COULD MOVE THROUGH THE NRN LAKES AND PRODUCE
SOME LIGHT PCPN. HOWEVER...WITH VERY LIMITED MOISTURE AND LITTLE
INSTABILITY...CONFIDENCE IN ADDITIONAL PCPN DEVELOPING WAS LOW AND NO
ADDITIONAL RAIN WAS MENTIONED.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 401 AM EDT TUE SEP 2 2014
THOUGH ACTIVE WEDNESDAY NIGHT INTO THURSDAY EVENING...THE REST OF
LONG TERM WILL BE QUIET AS HIGH PRESSURE DOMINATES FROM FRIDAY INTO
EARLY NEXT WEEK.
STARTING ON WEDNESDAY...WEAKER SHORTWAVES WORK THEIR WAY ACROSS
NORTHERN PLAINS AND TO UPPER GREAT LAKES BY LATE IN THE DAY IN A
ZONAL FLOW PATTERN ALOFT. LARGE SCALE LIFT IS PRESENT BUT THERE IS
NOT MUCH FOR A STRONGER SHORTWAVE AND ALSO OVERALL MOISTURE IS
LIMITED. BULK OF SHRA/TSRA LATER ON WEDNESDAY SHOULD STAY WEST OF
UPR MICHIGAN...MAINLY OVER CENTRAL AND SOUTHERN MINNESOTA CLOSER TO
SFC WARM FRONT AND BUILDING INSTABILITY. COULD SEE ISOLD SHRA/TSRA
OVER WESTERN LK SUPERIOR OR EVEN FAR WEST UPR MICHIGAN DUE TO
GENERAL H85-H7 WARM AIR ADVECTION AND MID-LEVEL MOISTURE ADVECTION.
TEMPS ON WEDNESDAY SHOULD PUSH INTO THE UPPER 70S OR LOWER 80S EVEN
WITH SCT-BKN MID CLOUDS IN THE AFTN.
POTENTIAL FOR PERIOD OF ACTIVE WEATHER WEDNESDAY NIGHT INTO THURSDAY
MORNING AS THE APPROACH OF A SFC LOW OVER THE NORTHERN PLAINS INCREASES
LOW-LEVEL JET /40 KTS AT H85/ INTO THE UPPER GREAT LAKES. SINCE THERE
IS NOT REALLY A STRONG SHORTWAVE MOVING THROUGH AT THAT TIME THOUGH...THINK
THAT THE BULK OF SHRA/TSRA WILL BE VCNTY OF WHERE LOW- LEVEL JET
INTERSECTS THE SFC-H85 WARM FRONT. BASED ON SFC WINDS AND DWPNTS...BEST
GUESS AT LOCATION OF THAT BOUNDARY IS FM CNTRL MN INTO WESTERN WI
WEDNESDAY NIGHT. MAX INSTABILITY BOTH IN TERMS OF MLCAPE AND ELEVATED
MUCAPE WILL BE MAXIMIZED OVER MUCH OF MINNESOTA AND INTO WISCONSIN
WITH INSTABILITY TRAILING OFF CONSIDERABLY INTO UPR MICHIGAN AND LK
MICHIGAN/LOWER MICHIGAN. MAJORITY OF MODELS INDICATE WIDESPREAD QPF
OVER UPR MICHIGAN WEDNESDAY NIGHT...BUT HAVE MY DOUBTS ON THIS AS
MOST OF THE HEAVY SHRA/TSRA COULD END UP FARTHER SOUTH ALONG WARM
FRONT AND ALSO BASED ON H85-H3 THICKNESSES WHICH...ALONG WITH FORWARD
PROPAGATING CORFIDI VECTORS...CAN BE USED TO DETERMINE GENERAL MOTION
OF AN MCS. SIMILAR TO EARLIER IN THE NIGHT...THERE IS STILL MID-LEVEL
MOISTURE ADVECTION FARTHER NORTH OF THE BOUNDARY THOUGH SO CANNOT
COMPLETELY RULE OUT SHRA/TSRA MAKING IT ACROSS UPR MICHIGAN. ANOTHER
FACTOR THAT COULD BUMP SHRA/TSRA FARTHER NORTH INTO THE CWA IS
INCREASING CAPPING THAT DEVELOPS IN THE H8-H7 LAYER OUT AHEAD OF THE
SFC LOW. AT THIS POINT THOUGH IT APPEARS THAT MAIN EXTENT OF CAPPING
WILL REMAIN BACK OVER THE CENTRAL PLAINS ON WEDNESDAY NIGHT.
GIVEN THE CONCERNS ABOUT TSRA OVERAGE...BACKED DOWN A BIT ON THE
HIGHER POPS WE HAD GOING BUT DID KEEP POPS HIGH CHANCE TO LOW END
LIKELY WITH BETTER CHANCES OVER THE WEST INITIALLY SHIFTING TO THE
EAST FOLLOWING THE TREND OF H7-H5 Q-VECTOR CONVERGENCE TIED TO
INITIAL WEAK SHORTWAVE AND ALSO WHERE THIS FORCING SYNCS UP WITH
GREATER MID-LEVEL MOISTURE TRANSPORT. TSRA INTENSITY SHOULD DIMINISH
INTO THE EAST BY LATE WED NIGHT INTO THURSDAY MORNING AS SHRA/TSRA
OUTRUN GREATER POOL OF INSTABILITY OVER MINNESOTA AND WISCONSIN.
FOR THURSDAY...RETAINED MUCH OF THE PREVIOUS FORECAST SHOWING TREND
TOWARD LOWER POPS BY LATE THURSDAY MORNING IN WAKE OF THE INITIAL
SHRA/TSRA MOVING EAST THEN POPS RAMPING BACK UP IN THE AFTN WITH
POSSIBLE ADDITIONAL SHRA/TSRA AHEAD OF APPROACHING COLD FRONT.
CAPPING SHOULD INCREASE MARKEDLY BY LATE MORNING/EARLY AFTN BASED
ON FORECAST SOUNDINGS SO THIS WILL IMPACT ADDITIONAL DEVELOPMENT OF
SHRA/TSRA. COULD GET QUITE WARM WITH EVEN JUST A LITTLE CLEARING.
MIXING TO H9 WITH SHARPER INVERSION AROUND THAT LEVEL SHOWN ON
SOUNDINGS MAY BE CONSERVATIVE BUT STILL RESULTS IN HIGHS AROUND 80
OVER MUCH OF CWA. NUDGED TEMPS UP INTO THE LOWER 80S AS A STARTING
POINT...BUT A MUGGY DAY /SFC DWPNTS 65-70/ WITH MID 80S IS CERTAINLY
POSSIBLE IN SOME AREAS. PRIMARY SHORTWAVE DRIVING THE COLD FRONT WILL
BE JUST NORTH OF MINNESOTA BY LATE THURSDAY AFTN. GIVEN THE WARM AND
HUMID AIRMASS...MLCAPES AHEAD OF THE FRONT OVER WEST HALF OF CWA
COULD PUSH OVER 2500J/KG...BUT MAIN QUESTIONS ARE HOW MUCH DEEPER
MOISTURE WILL BE AROUND AHEAD OF THE FRONT AND WILL CAPPING IN THE
H8-H7 LAYER BE TOO STRONG TO PROHIBIT SHRA/TSRA FROM DEVELOPING?
BASED ON CONSENSUS OF MODELS AND LATEST TRENDS...SEEMS THAT THERE IS
A RISK OF STORMS FORMING MID-LATE THURSDAY AFTN OVER THE WEST AND
AFFECTING REST OF CWA INTO THE EARLY EVENING AS BETTER MOISTURE IS
RE-INTRODUCED INTO THE AREA FM THE WEST/SOUTHWEST AND LIFT INCREASES
AND CAPPING DECREASES AS SHORTWAVE AND H5 SPEED MAX DRAW CLOSER. GIVEN
THE DEGREE OF INSTABILITY...IF STORMS FORM...SEVERE WEATHER POTENTIAL
IS ELEVATED AS 0-6KM SHEAR IS OVER 45 KTS AND 0-3KM SHEAR IS OVER 30
KTS. THE FORECASTED INSTABILITY...IF IT IS INDEED REALIZED...AND
SUCH SHEAR WOULD SUPPORT ROTATING/SUPERCELL TYPE STORMS AND ALSO
POTENTIAL FOR STORMS CONSOLIDATING INTO SEVERE WIND GUST PRODUCING
MCS ALONG THE COLD FRONT. A CONDITIONAL RISK ATTM...BUT CERTAINTLY
WORTH MONITORING AS WE GET CLOSER TO THIS TIME FRAME. SPC DAY3
OUTLOOK HIGHLIGHTS WI INTO WEST HALF OF UPR MICHIGAN WITH A 15 PCT
RISK FOR SEVERE /SLIGHT CATEGORICAL RISK/. WILL MENTION POTENTIAL
FOR SEVERE IN THE MORNING HAZARDOUS WEATHER OUTLOOK.
ONCE THE COLD FRONT SLIDES THROUGH ON THURSDAY NIGHT...ANY LINGERING
SHRA/TSRA WILL QUICKLY COME TO AN END BY THE OVERNIGHT SOUTH AND
EAST CWA. MAIN ISSUE LATE THURSDAY NIGHT INTO FRIDAY WILL BE GUSTY
NORTHWEST WINDS ON LK SUPERIOR AS IT BECOMES UNSTABLE IN THE 1000-900MB
LAYER. MIXED LAYER WINDS ARE OVER 30 KTS SO IT COULD BE GUSTY ALONG
THE LK SUPERIOR SHORE TO BEGIN THE DAY ON FRIDAY. DUE TO PRESSURE
RISES BTWN DEPARTING LOW AND APPROACHING HIGH...EVEN HIGHER WINDS
WOULD NOT BE OUT OF QUESTION. INCREASING WAVE ACTION WOULD ALSO LEAD
TO HIGH SWIM RISK ON BEACHES FROM MARQUETTE TO GRAND MARAIS.
QUIET WEATHER FOR THE WEEKEND AS IT LOOKS NOW. HIGH PRESSURE SETTLES
OVERHEAD AND STAYS IN PLACE INTO EARLY NEXT WEEK. TEMPS AT NIGHT MAY
DIP BLO 40 DEGREES IN THE INTERIOR. DAYTIME HIGHS WILL BE SEASONABLY
COOL IN THE 60S FOR MOST AREAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 738 AM EDT TUE SEP 2 2014
EXPECT VFR CONDITIONS TO PREVAIL THIS FCST PERIOD WITH RELATIVELY
DRY LOW LEVEL AIR DOMINATING. AN APPROACHING UPPER DISTURBANCE ALONG
WITH DAYTIME HEATING AND DESTABILIZATION COULD CAUSE SOME -SHRA AT
SAW AND PERHAPS IWD THIS AFTN...BUT THE DRY LOW LEVEL AIR SHOULD
MAINTAIN PREDOMINANT VFR WX EVEN IF THE -SHRA OCCUR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT TUE SEP 2 2014
WINDS WILL BE 20 KNOTS OR LESS THROUGH MOST OF THIS FORECAST PERIOD
EXCEPT FOR THU NIGHT INTO FRI WHEN WEST TO NORTHWEST WINDS BEHIND A
STRONG COLD FRONT WILL APPROACH 30 KNOTS. THIS WILL BE THE WHEN THE
STRONGEST WINDS OCCUR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
502 AM EDT TUE SEP 2 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE SEP 2 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD LOW AMPLITUDE
MID/UPPER LEVEL TROUGH THROUGH FROM THE NRN PLAINS INTO THE UPPER MS
VALLEY AND WRN GREAT LAKES WITH SEVERAL WEAK EMBEDDED SHORTWAVES.
ONE WAS LOCATED FROM SW MN INTO NW IA WHILE ANOTHER UPSTREAM SHRTWV
WAS MOVING THROUGH NORTH DAKOTA. AT THE SFC...WRLY FLOW PREVAILED
ACROSS UPPER MI BETWEEN A 987 MB LOW NEAR JAMES BAY AND A WEAK RIDGE
INTO THE CNTRL PLAINS.IR LOOP SHOWED MAINLY CLEAR SKIES ACROSS MOST
OF THE CWA BUT WITH INCREASING CLOUDS FROM MN INTO NW WI AND WRN
UPPER MI AHEAD OF THE SW MN SHRTWV.
TODAY...MOST OF THE FORCING ASSOCIATED WITH THE MN SHRTWV IS
EXPECTED TO REMAIN SOUTH OF UPPER MI. HOWEVER...THE COMBINATION OF
DAYTIME HEATING AND 850-600 MB LAPSE RATES TO NEAR 7.5C/KM AND LOW
LEVEL CONV ALONG LAKE BREEZE BOUNDARIES(ESPECIALLY OVER THE EAST)
WILL SUPPORT ISOLD/SCT SHRA BY THIS AFTERNOON. AS THE NORTH DAKOTA
SHRTWV NEAR BY MID TO LATE AFTERNOON SOME ADDITIONAL WEAK QVECTOR
CONV MAY ALSO CONTRIBUTE TO PCPN CHANCES. ALTHOUGH MLCAPE VALUES
INTO THE 400-800 J/KG RANGE WILL BE MARGINAL FOR TS...SOME ISOLD COULD
DEVELOP. WITH FREEZING HEIGHTS ONLY NEAR 9K-10K FT...SOME SMALL HAIL
MAY BE POSSIBLE.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND THE SHRTWVS EXITING
TO THE EAST...ANY PCPN SHOULD QUICKLY DIMINISH. WITH THE FAST
MID/UPPER LEVEL FLOW ACROSS THE NRN CONUS...MODELS SUGGEST THAT
ANOTHER WEAK SHRTWV COULD MOVE THROUGH THE NRN LAKES AND PRODUCE
SOME LIGHT PCPN. HOWEVER...WITH VERY LIMITED MOISTURE AND LITTLE
INSTABILITY...CONFIDENCE IN ADDITIONAL PCPN DEVELOPING WAS LOW AND NO
ADDITIONAL RAIN WAS MENTIONED.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 401 AM EDT TUE SEP 2 2014
THOUGH ACTIVE WEDNESDAY NIGHT INTO THURSDAY EVENING...THE REST OF
LONG TERM WILL BE QUIET AS HIGH PRESSURE DOMINATES FROM FRIDAY INTO
EARLY NEXT WEEK.
STARTING ON WEDNESDAY...WEAKER SHORTWAVES WORK THEIR WAY ACROSS
NORTHERN PLAINS AND TO UPPER GREAT LAKES BY LATE IN THE DAY IN A
ZONAL FLOW PATTERN ALOFT. LARGE SCALE LIFT IS PRESENT BUT THERE IS
NOT MUCH FOR A STRONGER SHORTWAVE AND ALSO OVERALL MOISTURE IS
LIMITED. BULK OF SHRA/TSRA LATER ON WEDNESDAY SHOULD STAY WEST OF
UPR MICHIGAN...MAINLY OVER CENTRAL AND SOUTHERN MINNESOTA CLOSER TO
SFC WARM FRONT AND BUILDING INSTABILITY. COULD SEE ISOLD SHRA/TSRA
OVER WESTERN LK SUPERIOR OR EVEN FAR WEST UPR MICHIGAN DUE TO
GENERAL H85-H7 WARM AIR ADVECTION AND MID-LEVEL MOISTURE ADVECTION.
TEMPS ON WEDNESDAY SHOULD PUSH INTO THE UPPER 70S OR LOWER 80S EVEN
WITH SCT-BKN MID CLOUDS IN THE AFTN.
POTENTIAL FOR PERIOD OF ACTIVE WEATHER WEDNESDAY NIGHT INTO THURSDAY
MORNING AS THE APPROACH OF A SFC LOW OVER THE NORTHERN PLAINS INCREASES
LOW-LEVEL JET /40 KTS AT H85/ INTO THE UPPER GREAT LAKES. SINCE THERE
IS NOT REALLY A STRONG SHORTWAVE MOVING THROUGH AT THAT TIME THOUGH...THINK
THAT THE BULK OF SHRA/TSRA WILL BE VCNTY OF WHERE LOW- LEVEL JET
INTERSECTS THE SFC-H85 WARM FRONT. BASED ON SFC WINDS AND DWPNTS...BEST
GUESS AT LOCATION OF THAT BOUNDARY IS FM CNTRL MN INTO WESTERN WI
WEDNESDAY NIGHT. MAX INSTABILITY BOTH IN TERMS OF MLCAPE AND ELEVATED
MUCAPE WILL BE MAXIMIZED OVER MUCH OF MINNESOTA AND INTO WISCONSIN
WITH INSTABILITY TRAILING OFF CONSIDERABLY INTO UPR MICHIGAN AND LK
MICHIGAN/LOWER MICHIGAN. MAJORITY OF MODELS INDICATE WIDESPREAD QPF
OVER UPR MICHIGAN WEDNESDAY NIGHT...BUT HAVE MY DOUBTS ON THIS AS
MOST OF THE HEAVY SHRA/TSRA COULD END UP FARTHER SOUTH ALONG WARM
FRONT AND ALSO BASED ON H85-H3 THICKNESSES WHICH...ALONG WITH FORWARD
PROPAGATING CORFIDI VECTORS...CAN BE USED TO DETERMINE GENERAL MOTION
OF AN MCS. SIMILAR TO EARLIER IN THE NIGHT...THERE IS STILL MID-LEVEL
MOISTURE ADVECTION FARTHER NORTH OF THE BOUNDARY THOUGH SO CANNOT
COMPLETELY RULE OUT SHRA/TSRA MAKING IT ACROSS UPR MICHIGAN. ANOTHER
FACTOR THAT COULD BUMP SHRA/TSRA FARTHER NORTH INTO THE CWA IS
INCREASING CAPPING THAT DEVELOPS IN THE H8-H7 LAYER OUT AHEAD OF THE
SFC LOW. AT THIS POINT THOUGH IT APPEARS THAT MAIN EXTENT OF CAPPING
WILL REMAIN BACK OVER THE CENTRAL PLAINS ON WEDNESDAY NIGHT.
GIVEN THE CONCERNS ABOUT TSRA OVERAGE...BACKED DOWN A BIT ON THE
HIGHER POPS WE HAD GOING BUT DID KEEP POPS HIGH CHANCE TO LOW END
LIKELY WITH BETTER CHANCES OVER THE WEST INITIALLY SHIFTING TO THE
EAST FOLLOWING THE TREND OF H7-H5 Q-VECTOR CONVERGENCE TIED TO
INITIAL WEAK SHORTWAVE AND ALSO WHERE THIS FORCING SYNCS UP WITH
GREATER MID-LEVEL MOISTURE TRANSPORT. TSRA INTENSITY SHOULD DIMINISH
INTO THE EAST BY LATE WED NIGHT INTO THURSDAY MORNING AS SHRA/TSRA
OUTRUN GREATER POOL OF INSTABILITY OVER MINNESOTA AND WISCONSIN.
FOR THURSDAY...RETAINED MUCH OF THE PREVIOUS FORECAST SHOWING TREND
TOWARD LOWER POPS BY LATE THURSDAY MORNING IN WAKE OF THE INITIAL
SHRA/TSRA MOVING EAST THEN POPS RAMPING BACK UP IN THE AFTN WITH
POSSIBLE ADDITIONAL SHRA/TSRA AHEAD OF APPROACHING COLD FRONT.
CAPPING SHOULD INCREASE MARKEDLY BY LATE MORNING/EARLY AFTN BASED
ON FORECAST SOUNDINGS SO THIS WILL IMPACT ADDITIONAL DEVELOPMENT OF
SHRA/TSRA. COULD GET QUITE WARM WITH EVEN JUST A LITTLE CLEARING.
MIXING TO H9 WITH SHARPER INVERSION AROUND THAT LEVEL SHOWN ON
SOUNDINGS MAY BE CONSERVATIVE BUT STILL RESULTS IN HIGHS AROUND 80
OVER MUCH OF CWA. NUDGED TEMPS UP INTO THE LOWER 80S AS A STARTING
POINT...BUT A MUGGY DAY /SFC DWPNTS 65-70/ WITH MID 80S IS CERTAINLY
POSSIBLE IN SOME AREAS. PRIMARY SHORTWAVE DRIVING THE COLD FRONT WILL
BE JUST NORTH OF MINNESOTA BY LATE THURSDAY AFTN. GIVEN THE WARM AND
HUMID AIRMASS...MLCAPES AHEAD OF THE FRONT OVER WEST HALF OF CWA
COULD PUSH OVER 2500J/KG...BUT MAIN QUESTIONS ARE HOW MUCH DEEPER
MOISTURE WILL BE AROUND AHEAD OF THE FRONT AND WILL CAPPING IN THE
H8-H7 LAYER BE TOO STRONG TO PROHIBIT SHRA/TSRA FROM DEVELOPING?
BASED ON CONSENSUS OF MODELS AND LATEST TRENDS...SEEMS THAT THERE IS
A RISK OF STORMS FORMING MID-LATE THURSDAY AFTN OVER THE WEST AND
AFFECTING REST OF CWA INTO THE EARLY EVENING AS BETTER MOISTURE IS
RE-INTRODUCED INTO THE AREA FM THE WEST/SOUTHWEST AND LIFT INCREASES
AND CAPPING DECREASES AS SHORTWAVE AND H5 SPEED MAX DRAW CLOSER. GIVEN
THE DEGREE OF INSTABILITY...IF STORMS FORM...SEVERE WEATHER POTENTIAL
IS ELEVATED AS 0-6KM SHEAR IS OVER 45 KTS AND 0-3KM SHEAR IS OVER 30
KTS. THE FORECASTED INSTABILITY...IF IT IS INDEED REALIZED...AND
SUCH SHEAR WOULD SUPPORT ROTATING/SUPERCELL TYPE STORMS AND ALSO
POTENTIAL FOR STORMS CONSOLIDATING INTO SEVERE WIND GUST PRODUCING
MCS ALONG THE COLD FRONT. A CONDITIONAL RISK ATTM...BUT CERTAINTLY
WORTH MONITORING AS WE GET CLOSER TO THIS TIME FRAME. SPC DAY3
OUTLOOK HIGHLIGHTS WI INTO WEST HALF OF UPR MICHIGAN WITH A 15 PCT
RISK FOR SEVERE /SLIGHT CATEGORICAL RISK/. WILL MENTION POTENTIAL
FOR SEVERE IN THE MORNING HAZARDOUS WEATHER OUTLOOK.
ONCE THE COLD FRONT SLIDES THROUGH ON THURSDAY NIGHT...ANY LINGERING
SHRA/TSRA WILL QUICKLY COME TO AN END BY THE OVERNIGHT SOUTH AND
EAST CWA. MAIN ISSUE LATE THURSDAY NIGHT INTO FRIDAY WILL BE GUSTY
NORTHWEST WINDS ON LK SUPERIOR AS IT BECOMES UNSTABLE IN THE 1000-900MB
LAYER. MIXED LAYER WINDS ARE OVER 30 KTS SO IT COULD BE GUSTY ALONG
THE LK SUPERIOR SHORE TO BEGIN THE DAY ON FRIDAY. DUE TO PRESSURE
RISES BTWN DEPARTING LOW AND APPROACHING HIGH...EVEN HIGHER WINDS
WOULD NOT BE OUT OF QUESTION. INCREASING WAVE ACTION WOULD ALSO LEAD
TO HIGH SWIM RISK ON BEACHES FROM MARQUETTE TO GRAND MARAIS.
QUIET WEATHER FOR THE WEEKEND AS IT LOOKS NOW. HIGH PRESSURE SETTLES
OVERHEAD AND STAYS IN PLACE INTO EARLY NEXT WEEK. TEMPS AT NIGHT MAY
DIP BLO 40 DEGREES IN THE INTERIOR. DAYTIME HIGHS WILL BE SEASONABLY
COOL IN THE 60S FOR MOST AREAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 122 AM EDT TUE SEP 2 2014
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD WITH
RELATIVELY DRY LLVL AIR SHOWN ON UPSTREAM RAOBS DOMINATING. AN
APRCHG UPR DISTURBANCE/DAYTIME HEATING AND DESTABILIZATION COULD
CAUSE SOME -SHRA AT SAW AND PERHAPS IWD THIS AFTN...BUT THE DRY LLVL
AIR SHOULD MAINTAIN PREDOMINANT VFR WX EVEN IF THE -SHRA OCCUR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT TUE SEP 2 2014
WINDS WILL BE 20 KNOTS OR LESS THROUGH MOST OF THIS FORECAST PERIOD
EXCEPT FOR THU NIGHT INTO FRI WHEN WEST TO NORTHWEST WINDS BEHIND A
STRONG COLD FRONT WILL APPROACH 30 KNOTS. THIS WILL BE THE WHEN THE
STRONGEST WINDS OCCUR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS JACKSON MS
1052 AM CDT TUE SEP 2 2014
.UPDATE...
SOME ADJUSTMENTS WERE MADE TO THE POPS AND QPF FOR THIS AFTERNOON
AND EVENING...AND MINOR ADJUSTMENTS WERE MADE TO TEMPERATURES. ALL
ELSE IS GENERALLY ON TRACK.
&&
.DISCUSSION...A DIFFICULT FORECAST SCENARIO EXISTS FOR TODAY
AS CONVECTIVE OUTFLOW PUSHES SOUTH ACROSS ARKANSAS AND TOWARD
NORTHWEST PORTIONS OF THE ARKLAMISS...WHILE THE BEST LOW LEVEL
CONVERGENCE SETS UP GENERALLY ALONG THE NATCHEZ TRACE CORRIDOR. THIS
PATTERN IS RESULTING IN LOW LEVEL DRY AIR ADVECTION AHEAD OF THE
SOUTHWARD MOVING BOUNDARY AND THIS MAY LIMIT CONVECTIVE DEVELOPMENT
LATER THIS AFTERNOON OVER PORTIONS OF NORTHEAST LOUISIANA INTO
WESTERN MS. HOWEVER...BASED ON THE LATEST HRRR AND LOCAL WRF
GUIDANCE...EXPECT CONSIDERABLE SHOWER/TSTM DEVELOPMENT ALONG THE
SAID MOIST-CONVERGENCE AXIS WHERE PRECIPITABLE WATER IN EXCESS OF TWO
INCHES AND SB CAPE ~3500 J/KG WILL EXIST. LAPSE RATES WILL BE
MARGINAL FOR GETTING A FEW SEVERE STORMS.
OVERALL... HAVE ADJUSTED POPS TO BETTER REFLECT THE ABOVE SCENARIO...
INCREASED THEM EAST AND DECREASED THEM OVER PORTIONS OF THE LA/MS
DELTA REGION...BUT THIS IS NOT A HIGH CONFIDENCE FORECAST GIVEN
10-15 KTS OF LOW LEVEL FLOW AND NUMEROUS OUTFLOW BOUNDARIES LIKELY TO
EXIST. /EC/
&&
.AVIATION...CEILINGS WERE SLOWLY LIFTING ACROSS THE REGION...WITH
MVFR CONDITIONS AT MOST LOCATIONS. THROUGH NOON...LOOK FOR CEILING
TO CONTINUE TO LIFT. SHOWERS WILL REMAIN IN THE VICINITY OF JACKSON
GOING INTO THE AFTERNOON. WITH CLOUDS LINGERING OVER THE AREA...NOT
SURE HOW MUCH THUNDER WILL BE AROUND...BUT WILL CONTINUE THE VCTS
FROM 20-24Z. A BOUNDARY OFF TO NORTHWEST WAS SLOWLY MOVING IN THIS
DIRECTION...BUT MODELS SUGGEST IT WILL NOT MAKE IT THIS FAR SOUTH.
MODELS SEEM TO DISAGREE ABOUT FOG DEVELOPMENT FOR TONIGHT BUT AGREE
STRATUS SHOULD NOT DEVELOP. WILL ADD PATCHY FOG TO ALL SITES FROM
8-12Z.
&&
.PREV DISCUSSION... /ISSUED 351 AM CDT TUE SEP 2 2014/
DISCUSSION...
TODAY THROUGH WEDNESDAY
GREATER COVERAGE OF SHOWERS AND THUNDERSTORMS EXPECTED TODAY VS.
YESTERDAY WITH SOME POSSIBLY ON THE STRONG TO BRIEFLY SEVERE SIDE IN
WEST AND SOUTHWEST AREAS. TEMPERATURES WILL RISE QUICKLY THROUGH
MORNING HOURS BUT BE TEMPERED BY SHOWER COVERAGE DURING THE AFTN.
A SWIFT MOVING S/WV TROUGH ACROSS THE CENTRAL PLAINS IS SUSTAINING A
MCS IN KS/OK/MO THIS MORNING AND IS ACTING TO FLATTEN THE ALREADY
WEAK H7-H5 RIDGING OVER THE LOWER MS VALLEY. HI-RES GUIDANCE
INDICATES THE MCS WILL SHIFT INTO OK/AR THROUGH THE DAWN HOURS AND
SLOWLY WEAKEN AS IT GUSTS OUT. HOWEVER, HRRR/ARW SUGGEST A
CONVERGENT BAND DEVELOPING FROM THIS OUTFLOW IN SOUTH AR AND NORTH LA
BY LATE MORNING TO EARLY AFTN THAT COULD SERVE AS A FOCUS FOR MORE
ORGANIZED ACTIVITY INTO WEST AND SOUTHWEST MS BY MID TO LATE AFTN.
AHEAD OF THIS BOUNDARY, IT SHOULD ALSO BE NOTED THAT WITH SUCH A WARM
START THIS MORNING, CONVECTIVE TEMPERATURES WILL BE REACHED 11AM-12PM
AND ISO/SCT SHOWERS/TSTORMS WILL LIKELY DEVELOP ACROSS THE I-20 AND
HWY 82 CORRIDORS. GREATER INSTABILITY WILL EXIST IN WEST IN
CONJUNCTION WITH POSSIBLE CONVERGENCE BAND AND THIS MAY PROMOTE
BETTER UPDRAFT STRENGTH AS SUPPORTED BY SPC SSEO OUTPUT. STORMS COULD
BECOME STRONG TO BRIEFLY SEVERE WITH LOCALIZED WINDS IN THE 40-60 MPH
RANGE AND FREQUENT LIGHTNING. WILL NOT FORMALLY INTRODUCE A LIMITED
THREAT OF SEVERE JUST YET AS TO MONITOR HI-RES TRENDS AND ALLOW FOR
MORNING SOUNDING ANALYSIS.
SHOWERS/STORMS WILL DIMINISH THROUGH THE MID EVENING HOURS BUT SOME
NEW ACTIVITY MAY DEVELOP IN NORTH MS ALONG AN ELEVATED BOUNDARY
EARLY WEDNESDAY MORNING AND HAVE PLACED 20% POPS FOR FAR NORTH TIER
COUNTIES. PWATS NEAR 2" WILL CONTINUE WEDNESDAY WITH ANOTHER ROUND
OF SHOWERS/STORMS EXPECTED DURING THE AFTERNOON HOURS. THIS ACTIVITY
ALSO SHOULD DECREASE THROUGH MID EVENING HOURS WITH QUIET
CONDITIONS OVERNIGHT THURSDAY EXPECTED. /ALLEN/
THURSDAY THROUGH MONDAY...
DEEP LAYERED RIDGE LOOKS TO REMAIN ANCHORED OVER THE LOWER CONUS
THROUGH THE PERIOD. THIS SHOULD KEEP THE MOIST AND UNSTABLE AIRMASS
LOCKED IN PLACE AND A CONTINUATION OF THE SENSIBLE WEATHER WE HAVE
BEEN EXPERIENCING.
WILL PRETTY MUCH HAVE TO CONTEND WITH AFTERNOON/EVENING AIRMASS
CONVECTION EACH DAY THROUGH THE EXTENDED TIME FRAME. ALTHOUGH
CONVECTIVE COVERAGE SHOULD REMAIN SCATTERED...STORMS MAY BE SOMEWHAT
MORE NUMEROUS OVER THE SOUTH WHERE INTERACTIONS WITH THE SEA BREEZE
MAY BE ENCOUNTERED. WENT CLOSE TO GFS MOS MAXIMUMS WITH HIGHS IN THE
LOW TO MID 90S AS BELIEVE THIS LEVEL OF WARMING WILL STILL BE LIKELY
GIVEN MID AFTERNOON CONVECTIVE INITIATION TIMES.
MOVING INTO THE WEEKEND...SUBTLE MID LEVEL TROFFINESS OVER THE
EASTERN PORTIONS OF THE COUNTRY WILL ALLOW A WEAK COLD FRONT TO EASE
INTO THE REGION FROM THE NORTH SATURDAY NIGHT/SUNDAY. THE BOUNDARY
LOOKS AS THOUGH IT WILL QUICKLY STALL OVER THE NORTH AND NOT OFFER
ANYMORE THAN AN INCREASE IN CONVECTIVE COVERAGE FOR THE REMAINDER OF
THE WEEKEND AND THE FIRST PART OF NEXT WEEK. WHILE THE COOL AIR
BEHIND THE BOUNDARY SHOULD STAY TO THE NORTH OF THE AREA...INCREASED
CONVECTION SUNDAY AND MONDAY SHOULD ONLY ALLOW MAXIMUMS TO REACH
AROUND 90...BUT OVERNIGHT LOWS WILL REMAIN IN THE LOWER 70S./26/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 92 73 94 72 / 50 27 32 19
MERIDIAN 93 72 94 71 / 49 24 41 17
VICKSBURG 92 72 94 72 / 51 24 24 19
HATTIESBURG 94 75 95 73 / 52 30 50 21
NATCHEZ 90 74 92 72 / 54 30 40 23
GREENVILLE 93 73 94 73 / 50 20 19 14
GREENWOOD 92 73 94 72 / 46 20 27 14
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
359 PM EDT TUE SEP 2 2014
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY
THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY
HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY,
DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER
RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN
EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
AS OF 355 PM EDT TUESDAY...WELL, THE ATMOSPHERE IS FAIRLY PRIMED.
VERY WARM AND HUMID AIRMASS IS RESULTING IN MODEST SURFACE BASED
INSTABILITY (CAPE PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO
-4C). SO FAR THE ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST
AREA, HOWEVER RADAR SHOWS THE BUILDING LINE OF SHOWERS AND
THUNDERSTORMS OUT ACROSS ONTARIO. THESE STORMS SHOULD BE CROSSING
INTO THE UNITED STATES IN THE NEXT COUPLE OF HOURS. STILL LIKE HOW
THE HRRR AND OUR LOCAL 6KM WRF ARE HANDLING THE EVOLUTION OF THE
CONVECTION. STILL LOOKS LIKE AN ETA INTO THE CHAMPLAIN VALLEY
DURING THE EVENING (LET`S GO WITH 6-8PM) AND THEN INTO EASTERN
VERMONT BY 10PM. UPPER LEVEL SHORTWAVE WHICH IS THE PRIMARY
TRIGGER FOR THE CONVECTION IS NOW OVER MICHIGAN AND STARTING TO
LIFT NORTHEAST. OUT AHEAD OF THAT SHORT WAVE THE WIND FIELDS AND
RELATED SHEAR INCREASE, BUT AT THE SAME TIME WE ARE GETTING CLOSER
TO SUNSET AND LOSS OF HEATING. SO IT`S A BATTLE BETWEEN TIMING OF
THE BEST DYNAMICS VS BEST INSTABILITY.
AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE
AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND
MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF
GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS.
THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY
TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH
CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT.
THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY
NIGHT WITH LOWS IN THE 60S.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM
MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION.
DAILY SPECIFICS...
WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB
TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES
IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD
DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE
AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND
THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE
BREEZY IN THE AFTERNOON.
WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY
FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL
BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN
THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE.
THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY
OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB
TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR
HIGHS. PLENTY OF SUN AS WELL.
THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH
THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING
CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY
CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW
DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR
LOWS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY
QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER
PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE
PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY
AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT
SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL
ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED.
IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH
WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND
THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT
WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE
EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR
NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW
SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS
MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING
THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED
ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF.
BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS
THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS
EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST
THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE
TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN
TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH
EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW
70S...AND LOWS IN THE MID 40S TO LOW 50S.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THROUGH 12Z WEDNESDAY...CURRENT VFR ACROSS THE AREA WILL
DETERIORATE TO VARIABLE FLIGHT CONDITIONS AS SHOWERS AND
THUNDERSTORMS DEVELOP ALONG/AHEAD OF A COLD FRONT AND MOVE ACROSS
THE AREA THIS AFTERNOON THROUGH MIDNIGHT. CIGS WILL PRIMARILY
REMAIN VFR BUT VSBY WILL BE REDUCED TO MVFR/IFR AS STORMS PASS.
AFTER 06Z...PRECIP IS EAST OF THE REGION LEAVING GENERALLY CLOUDY
SKIES. CIGS OVERNIGHT WILL GENERALLY BE VFR AT KMSS/KPBG/KBTV...BUT
MVFR AT KRUT/KSLK/KMPV WITH POSSIBLE IFR AT KRUT UNDER BLOCKED
FLOW. AFTER 12Z...ALL CIGS LIFT TO VFR WITH SCT-BKN DIURNAL
STRATOCUMULUS EXPECTED THROUGH THE DAY.
OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...
18Z WED - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS
AND THUNDERSTORMS.
00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NASH
NEAR TERM...NASH
SHORT TERM...NASH
LONG TERM...LAHIFF
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
133 PM EDT TUE SEP 2 2014
.SYNOPSIS...
EXPECT SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND TONIGHT ACROSS
MUCH OF THE NORTH COUNTRY AS A COLD FRONT MOVES INTO THE REGION.
SOME OF THE STORMS WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS,
HEAVY DOWNPOURS AND POSSIBLY SMALL HAIL. THE COLD FRONT EXITS THE
REGION TONIGHT AND SLIGHTLY COOLER AND DRIER WEATHER IS EXPECTED
FOR WEDNESDAY AND THURSDAY AS HIGH PRESSURE BUILDS INTO THE
REGION.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 130 PM EDT TUESDAY...EARLY AFTERNOON REFRESH FEATURES SLIGHT
UPWARD MODIFICATIONS IN TEMPERATURES (ALREADY 87F HERE AT BTV) AND
A SLIGHT FINE TUNING OF THE POP/WEATHER EVOLUTION FOR THE NEXT 12
HOURS. OTHERWISE THE OVERALL SCENARIO FOR A LINE OF THUNDERSTORMS
TO DEVELOP IN THE NEXT FEW HOURS AND ROLL FROM WEST TO EAST ACROSS
THE FORECAST AREA IS STILL UNCHANGED.
LAPS SHOWS DECENT AMOUNT OF SURFACE INSTABILITY WITH TEMPERATURES
WELL INTO THE 80S AND DEWPOINTS PUSHING 70F IN MANY AREAS. CAPE
VALUES UP AROUND 1500 J/KG. FROM THE LOOK OF THE CLOUDS AND
RELATIVE LACK OF DEVELOPMENT CURRENTLY ON RADAR OVER NORTHERN NY
AND MOST OF VERMONT, IT APPEARS THERE IS STILL A WEAK CAP AND DRY
AIR ALOFT (THAT SHOWED ON 12Z SOUNDINGS).
HOWEVER, LOOKING FARTHER TO THE WEST OVER ONTARIO SHOWS WHAT IS
HEADING THIS WAY.
6KM LOCAL WRF MODEL AND 15Z HRRR ARE PRETTY CLOSE IN THE OVERALL
EVOLUTION, AND BOTH SEEM REASONABLE. HAVE LEANED TOWARD THEIR
OUTPUT FOR POPULATING THE GRIDS. IF ANYTHING, THEY (AS TYPICAL)
MIGHT BE AN HOUR OR TWO TOO SLOW IN TIMING.
WE SHOULD SEE THE STORMS TO THE WEST CONTINUE TO EVOLVE INTO A
SEMI-CONTINUOUS LINE. THESE STORMS SHOULD REACH THE ST LAWRENCE
VALLEY ABOUT 20Z, THE CHAMPLAIN VALLEY ABOUT 22-23Z AND THEN INTO
EASTERN VERMONT BY 01Z. THINK PRIMARY THREAT REMAINS GUSTY WINDS
(THANKS TO MODERATE WINDS ALOFT AND THE DRY AIR AT MID LEVELS
WHICH COULD ENHANCE DOWNBURST POTENTIAL) ALONG WITH HEAVY RAIN
(GUIDANCE SUGGEST PRECIPITABLE WATER VALUES APPROACH 2". SHOULD
NOT BE AN OVER THE TOP SEVERE WEATHER DAY, BUT IT WILL BE A BIT
BUSY LATER THIS AFTERNOON INTO THE EARLY EVENING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH THURSDAY/...
AS OF 421 AM EDT TUESDAY...SHOWERS AND STORMS SHOULD END FROM WEST
TO EAST ACROSS THE AREA TONIGHT WITH ACTIVITY EXITING MOST OF THE
AREA AFTER MIDNIGHT. WESTERLY FLOW ALOFT THEN DEVELOPS FOR WEDNESDAY
AND THURSDAY AND HIGH PRESSURE BUILDS IN FROM THE WEST. THIS WILL
KEEP THE FORECAST DRY DURING THIS PERIOD AND WITH HIGH PRESSURE
BUILDING IN FROM THE WEST AND NOT THE NORTHWEST...COLDER AIR WILL
NOT MAKE IT INTO THE REGION. SO EVEN THOUGH CONDITIONS WILL BE
COOLER THAN THE PAST COUPLE OF DAYS...HIGH TEMPERATURES WILL BE AT
OR SLIGHTLY ABOVE SEASONAL NORMALS WITH READINGS IN THE 70S TO
AROUND 80.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 410 AM EDT TUESDAY...FORECAST AREA PREDOMINANTLY UNDER
WESTERLY UPPER LEVEL FLOW WITH EASTERN US RIDGE NOSING INTO NEW
ENGLAND EARLY IN THE EXTENDED PERIOD...FOLLOWED BY LOWERING
HEIGHTS AND BROAD TROUGH ESTABLISHED FROM THE WEEKEND ONWARD.
GENERALLY QUIET WEATHER DURING THE EXTENDED PERIOD EXPECT FOR
FRONTAL PASSAGE FOR THE WEEKEND BRINGING CHANCES FOR RAIN.
RISING HEIGHTS AND WARMING TEMPERATURES THURSDAY INTO FRIDAY AS
RIDGE BUILDS INTO THE NORTHEAST IN ADVANCE OF NEXT SURFACE FRONT.
BY FRIDAY...850 MB TEMPS HIT THE UPPER TEENS...WHICH WOULD SUPPORT
VERY WARM HIGHS IN THE MID TO UPPER 80S...A GOOD 10 DEGREES ABOVE
NORMAL. GIVEN 850 MB TEMPS...ADJUSTED MAX TEMPS ON FRIDAY UP A
DEGREE OR TWO ABOVE GUIDANCE.
500 MB TROUGH AND ASSOCIATED SURFACE FRONT MOVES ACROSS THE NORTHERN
US TIER STATES THROUGH MID WEEK...THEN LIFTS NORTH ACROSS CENTRAL
QUEBEC LATE IN THE WEEK INTO THE WEEKEND. TRAILING COLD FRONT ENTERS THE
SAINT LAWRENCE VALLEY LATE FRIDAY AND MOVES THROUGH THE FORECAST
AREA OVER THE WEEKEND. WITH BEST UPPER DYNAMICS AND SURFACE LOW
PASSING TO NORTH...SURFACE BOUNDARY SLOWS AND BECOMES ORIENTED
MORE NORTHEAST TO SOUTHWEST...PARALLEL WITH UPPER FLOW. MODEL
DIFFERENCES BECOME APPARENT LATE SATURDAY INTO SUNDAY...WITH GFS
MOVING THE SURFACE BOUNDARY AND PRECIPITATION TO THE NEW ENGLAND
COAST...WHILE ECMWF HANGS IT UP IN INTERIOR NEW ENGLAND. HEDGED
TOWARD THE ECMWF SOLUTION AND KEPT CHANCE POPS INTO SUNDAY. RIGHT
NOW SATURDAY HAS THE BEST CHANCES FOR RAIN AND THUNDER...
COINCIDING FRONTAL PASSAGE WITH MAX DAYTIME HEATING. TEMPERATURES
DO RETURN TO SEASONAL NORMALS FOR THE WEEKEND WITH FRONTAL PASSAGE
AND LOWER HEIGHTS AS THE EASTERN RIDGE IS SUPPRESSED.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THROUGH 12Z WEDNESDAY...CURRENT VFR ACROSS THE AREA WILL
DETERIORATE TO VARIABLE FLIGHT CONDITIONS AS SHOWERS AND
THUNDERSTORMS DEVELOP ALONG/AHEAD OF A COLD FRONT AND MOVE ACROSS
THE AREA THIS AFTERNOON THROUGH MIDNIGHT. CIGS WILL PRIMARILY
REMAIN VFR BUT VSBY WILL BE REDUCED TO MVFR/IFR AS STORMS PASS.
AFTER 06Z...PRECIP IS EAST OF THE REGION LEAVING GENERALLY CLOUDY
SKIES. CIGS OVERNIGHT WILL GENERALLY BE VFR AT KMSS/KPBG/KBTV...BUT
MVFR AT KRUT/KSLK/KMPV WITH POSSIBLE IFR AT KRUT UNDER BLOCKED
FLOW. AFTER 12Z...ALL CIGS LIFT TO VFR WITH SCT-BKN DIURNAL
STRATOCUMULUS EXPECTED THROUGH THE DAY.
OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...
18Z WED - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS
AND THUNDERSTORMS.
00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...EVENSON
NEAR TERM...NASH
SHORT TERM...EVENSON
LONG TERM...HANSON
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1114 PM EDT WED SEP 3 2014
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST THROUGH THE FIRST HALF OF THE
WEEKEND. AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE
EACH DAY. A COLD FRONT MAY BRING AN INCREASE IN SHOWERS AND
THUNDERSTORMS FOR SUNDAY AND MONDAY. HIGH PRESSURE WILL BUILD INTO
THE REGION TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 1030 PM WEDNESDAY...UPDATE TO SKY CONDITIONS WITH MAINLY
CLEAR SKIES EXCEPT FOR SOME MID-HIGH LEVEL DEBRIS CLOUDS
POSSIBLE...ESPECIALLY INLAND ALONG AND WEST OF THE I-95 CORRIDOR.
WEAK LOW LEVEL ONSHORE FLOW FROM THE WESTERN EXTENT OF THE BERMUDA
HIGH...HAS PUSHED IN 70+ DEWPOINTS WELL INLAND WITH MID 70S ALONG
THE IMMEDIATE COAST. HAVE UPDATED TONIGHTS LOWS TO ACCOUNT FOR A
MORE HUMID AND TROPICAL AIRMASS ACROSS THE FA. MAINTAINED THE
PATCHY/AREAS OF FOG MAINLY INLAND...WEST OF THE INTRA-COASTAL
WATERWAY. A FEW ISOLATED LOCALES COULD SEE DENSE...IE. NORTHERN
ROBESON COUNTY WHERE HEAVY RAIN FELL LATE THIS AFTERNOON AND
EVENING.
PREVIOUS DISCUSSION..............................................
AS OF 730 PM WEDNESDAY...RIDGING SFC AND ALOFT WILL STRENGTHEN
SOME ACROSS THE AREA TONIGHT. THIS A RESULT OF THE WESTERN
ATLANTIC HIGH CONTINUING TO FLEX ITS MUSCLE ACROSS THE ILM
CWA...WITH FLOW SFC AND ALOFT FROM THE SE AND S. SOMEWHAT STABLE
LOW LEVEL MARINE LAYER HAS WORKED WELL INLAND THIS AFTN AND
TONIGHT...FURTHER THAN WHAT THE HRRR ANTICIPATED. ONE OF THE
REASONS WHY THE DEEPEST AND MORE ORGANIZED CONVECTION THIS AFTN
AND EVENING IS MAINLY LOCATED WEST OR NORTH OF THE ILM CWA. SOME
MAJOR POP RESTRUCTURING FOR THE REMAINDER OF THIS EVENING...WITH
LESS THAN ISOLATED CHANCE BY MID TO LATE THIS EVENING. INCREASED
THE FOG OUTLOOK FROM PATCHY TO AREAS...ESPECIALLY ACROSS LOCATIONS
RECEIVING THE HEAVY RAINFALL IE. NORTHERN ROBESON COUNTY. VERY
LITTLE TWEAKING NEEDED FOR OVERNIGHT TEMPS/DEWPTS AT THIS TIME
OTHER THAN WHERE PCPN OCCURRED.
PREVIOUS DISCUSSION...............................................
AS OF 245 PM WEDNESDAY...ANTICIPATED CU FIELD HAS BEGUN TO DEVELOP
WITH THE FAVORED LOCATION FOR NOW OVER THE COASTAL COUNTIES.
HOWEVER...OTHER THAN A TINY SHOWER DOWN AROUND GEORGETOWN...THE
FORECAST AREA REMAINS RAIN-FREE. ANALYSIS OF MORNING SOUNDINGS
CONFIRM EARLIER FORECAST REASONING...WITH AN UNSTABLE AND MOIST
ATMOSPHERE COMBINING WITH A NUMBER OF BOUNDARIES BOTH OLD AND NEW
TO GENERATE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
STARTING LATER THIS AFTERNOON. WEAK STEERING MEANS STORM MOTION
WILL BE SLOW...LEADING TO A THREAT OF LOCALIZED FLOODING.
OTHERWISE...SOME OF THE MORE VIGOROUS STORMS COULD GENERATE STRONG
AND GUSTY WINDS LATER THIS AFTERNOON.
THE CONVECTION...BEING DIURNAL IN NATURE...WILL FADE WITH THE
SETTING SUN. ALTHOUGH A SPOT SHOWER CANNOT BE RULED OUT...EXPECT A
DRY OVERNIGHT PERIOD WITH AREAS OF FOG DEVELOPING AFTER MIDNIGHT.
CONTINUED WARM SOUTHERLY FLOW WILL KEEP OVERNIGHT TEMPERATURES A
TAD ABOVE NORMAL...WITH LOWS IN THE LOWER TO MID 70S MOST PLACES.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 245 PM...A HIGH PRESSURE RIDGE AXIS WILL BE SITUATED
JUST TO THE NORTH OF THE FORECAST AREA ON THURSDAY AND THE CENTER OF
OF THE HIGH WILL SHIFT DIRECTLY OVERHEAD BY MIDDAY FRIDAY. SO ALOFT
WINDS WILL BE FROM THE EAST AT 500 MB ON THURSDAY AND LIGHT AND
VARIABLE AT THIS LEVEL ON FRIDAY. THE PRECIPITABLE WATERS ARE
EXPECTED TO DROP BELOW 2 INCHES AND SETTLE AROUND 1.75 INCHES DURING
THE SHORT TERM PERIOD. AT THE SURFACE SOUTH TO SOUTH-SOUTHWEST WIND
FLOW WILL DOMINATED THE FORECAST. SO EXPECT WIDELY SCATTERED TO
SCATTERED CONVECTION TO DEVELOP ALONG THE SEA BREEZE AND PUSH TO THE
NORTH AND NORTHEAST OUT OF THE AREA DURING EACH DAY. MODEL SOUNDING
ARE SHOWING VERY SLOW STORM MOTIONS EACH DAY SO ANY THUNDERSTORM
ESPECIALLY INLAND THAT DEVELOPS WILL BE ABLE TO PRODUCE VERY HEAVY
RAIN.
TEMPERATURES AT 850 MB ARE SEEN TO BE COOLING IN BOTH THE 12 UTC GFS
AND NAM. THE MODELS ARE INDICATING TEMPERATURES DROPPING 2 TO 2.5
DEGREES THURSDAY AND FRIDAY. SO MAXIMUM TEMPERATURES ARE EXPECTED TO
BE A COUPLE OF DEGREES COOLER BUT STILL WARM AND MUGGY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 245 PM WEDNESDAY...EXTENDED CONTINUES TO TREND TOWARD A
RATHER UNSETTLED SCENARIO AS BROAD TROUGHING MOVING WEST TO EAST
WILL ALLOW A FRONT TO SLOWLY MOVE ACROSS THE AREA. THE FRONT
BISECTS THE AREA SUNDAY AND HENCE THE HIGHEST POPS RESIDE HERE
WITH LIKELY VALUES OVER MOST OF THE AREA. THE SLOW MOVEMENT OF THE
SYSTEM WARRANTS GOOD CHANCE VALUES FOR MONDAY WITH THE HIGHEST
VALUES NEAR THE COAST. VALUES FALL EVEN FURTHER TUESDAY AND
WEDNESDAY BUT BEING THE LAST TWO DAYS OF THE PERIOD AND THE MODELS
HINTING AT THE FRONT HANGING UP ALONG THE COAST WARRANTS AT LEAST
SOME MENTION.
TEMPERATURE FORECAST TRENDS SLOWLY LOWER THROUGH THE PERIOD WITH
SATURDAY SHOWING ONE LAST DAY OF 90S AND 70S LOWERING TO 80S AND 60S
RESPECTIVELY THE REMAINDER OF THE PERIOD.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...POTENTIAL FOR MVFR/IFR DUE TO FOG LATE
OVERNIGHT/EARLY MORNING HOURS. OTHERWISE EXPECT VFR WITH A CHANCE
OF AFTERNOON SHRA/TSRA ON THURSDAY.
VFR PREVAILS ACROSS THE AREA THIS EVENING WITH SOUTH-SOUTHWEST WINDS
AROUND 5 TO 10 KTS AND SCT/BKN MID TO HIGH CLOUDS. LATEST RADAR
IMAGERY DEPICTS A FEW LIGHT SHOWERS ACROSS THE INLAND PORTIONS OF
THE AREA. THOUGH NOT CURRENTLY AFFECTING ANY TAF SITES...COULD NOT
RULE OUT THE POSSIBILITY OF A SHOWER MOVING ACROSS KFLO/KLBT OVER
THE NEXT FEW HOURS. OVERNIGHT INTO THE EARLY MORNING HOURS...SCT/BKN
CLOUDS WILL CONTINUE TO MOVE IN WITH FEW/SCT LOW STRATUS POSSIBLY
MOVING IN..ESPECIALLY INLAND...AND LIGHT WINDS. MODEL GUIDANCE
CONTINUES TO BE IN AGREEMENT WITH FOG DEVELOPMENT OVERNIGHT. THUS
HAVE KEPT WITH MVFR ALONG THE COAST...WITH MVFR/TEMPO IFR/LIFR INLAND.
ON THURSDAY...MORNING FOG WILL DISSIPATE GIVING WAY TO VFR WITH
SOUTH-SOUTHEAST WINDS INCREASING TO 10 TO 12 KTS...AND SLIGHTLY
HIGHER ALONG THE COAST. AFTERNOON SHRA/TSRA ARE POSSIBLE.
EXTENDED OUTLOOK...CHANCE OF SCATTERED AFTN SHOWERS/TSTMS THROUGH
FRIDAY. PATCHES OF MVFR/IFR FOG OR STRATUS MAY ALSO DEVELOP EACH
MORNING. A COLD FRONT DROPS INTO THE REGION SUNDAY AND MONDAY...WITH
A GOOD CHANCE FOR SHOWERS AND STORMS BOTH DAYS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM WEDNESDAY...WESTERN ATLANTIC SFC RIDGE AXIS TO LIE
ACROSS THE ATL WATERS OVERNIGHT...RESULTING WITH S-SW WINDS NORTH
OF CAPE FEAR...S WINDS SOUTH OF CAPE FEAR TO LITTLE RIVER
INLET...AND SE TO S FOR THE SOUTHERNMOST 2 ZONES. SFC PG REMAINS
LOOSE WITH SPEEDS AROUND 10 KT...EXCEPT 10 TO POSSIBLY 15 KT CAPE
FEAR NORTHWARD FOR MUCH OF THE NIGHT. LATEST SWAN OUTPUT INDICATES
A SOLID 2 TO 3 FOOT SIGNIFICANT SEAS...WITH AN ESE-SE GROUND SWELL
EXHIBITING AROUND 8 SECOND PERIODS DOMINATING THE WAVE SPECTRUM.
PREVIOUS DISCUSSION............................................
AS OF 745 PM WEDNESDAY...WESTERN ATLANTIC RIDGING SFC AND ALOFT
TO PREVAIL ACROSS THE WFO ILM COASTAL WATERS. SFC PRESSURE PATTERN
OVERNIGHT TO YIELD S-SW WIND DIRECTION ILM NC WATERS...AND SE-S
ACROSS THE ILM SC WATERS. SOMEWHAT RELAXED SFC PG ACROSS THE
WATERS TO YIELD AROUND 10 KT WIND SPEEDS...EXCEPT THIS EVENING
ROUGHLY THRU MIDNIGHT WHEN THE LEFTOVER SEA BREEZE CIRCULATION TO
ADD 5 KT...IE. EVENING SPEEDS AT 10-15 KT. ISOLATED NOCTURNAL ATL
CONVECTION SHOULD REMAIN JUST OFFSHORE.
PREVIOUS DISCUSSION...........................................
AS OF 245 PM WEDNESDAY...BERMUDA HIGH PRESSURE ANCHORED OVER THE
WESTERN ATLANTIC IS BRINGING SWLY WINDS IN THE 10 TO 15 KT RANGE
WITH 2 TO 3 FT SEAS OVER THE WATERS THIS AFTERNOON. EXPECT THESE
CONDITIONS TO PERSIST THROUGH THE OVERNIGHT HOURS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 PM WEDNESDAY...WITH THE BERMUDA HIGH IN PLACE SOUTHEAST TO
SOUTH WINDS WILL CONTINUE THROUGH THE SHORT TERM WITH WINDS AROUND
10 TO 15 KNOTS. SEAS AREA EXPECTED TO REMAIN GENERALLY AT OR LESS
THAN 3 FEET.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...IT APPEARS A SYNOPTIC WIND SHIFT IS IN
THE OFFING LATE SUNDAY AND CONTINUING INTO MONDAY AS A FRONT MAKES
ITS WAY ACROSS THE WATERS. WINDS WILL CONTINUE FROM THE
SOUTH/SOUTHWEST SATURDAY INTO EARLY SUNDAY AT 10-15 KNOTS.
NORTHEAST WINDS DEVELOP LATE SUNDAY BUT ARE RATHER WEAK...TEN
KNOTS OR LESS. SIGNIFICANT SEAS...BASICALLY ALL LOCAL WIND
GENERATED WAVES REMAIN TEPID IN A 2-3 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRH
NEAR TERM...DCH/REK
SHORT TERM...DRH
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
833 PM EDT WED SEP 3 2014
.SYNOPSIS...A SURFACE TROUGH WILL BE LOCATED OVER CENTRAL NORTH
CAROLINA INTO THURSDAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA
FOR THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 735 PM WEDNESDAY...
THE FOCUS FOR CONVECTION HAS BEEN OUTFLOW DRIVEN AND THE OUTFLOW
BOUNDARIES HAVE SHIFTED NORTHWARD WITH TIME... NOW AN WEST-EAST ARC
ACROSS NC EXTENDING FROM NEAR THE TRIAD TO THE TRIANGLE TO
GOLDSBORO. THIS FOCUS IS EXPECTED TO SLOWLY DRIVE NORTHWARD THROUGH
THE EVENING WHICH WILL TAKE THE CONVECTION INTO THE TRIAD...
TRIANGLE... AND GOLDSBORO/WILSON/ROCKY MOUNT REGIONS BEFORE
DIMINISHING TOWARD MIDNIGHT. OTHERWISE... ONLY ISOLATED STORMS AFTER
MIDNIGHT WITH MOSTLY CLOUDY SKIES BECOMING PARTLY CLOUDY. PATCHY
FOG. LOWS 68-73.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 PM WEDNESDAY...
THURSDAY AND THURSDAY NIGHT... MID LEVEL SHEAR AXIS WILL CONTINUE TO
WAVER ALONG THE VA BORDER BUT WEAKEN WITH TIME. MEANWHILE MID-UPPER
LEVEL HEIGHTS WILL SLOWLY RISE AS THE BERMUDA HIGH CENTERED OFFSHORE
BUILDS WEST INTO THE SE U.S. THE BUILDING HIGH ALOFT AND ASSOCIATED
WEAK SUBSIDENCE WILL INHIBIT CONVECTIVE DEVELOPMENT OVER MOST OF THE
SOUTHERN COUNTIES. EXPECT A FEW MORE STORMS ACROSS THE NORTH IN
VICINITY OF THE SFC BOUNDARY AND WEAKENING SHEAR AXIS. PLAN TO TAPER
POPS FROM CHANCE OVER THE FAR NORTH-NW...TO SLIGHT CHANCE OVER THE
SOUTHEAST. BULK OF CONVECTION WILL DIMINISH SHORTLY AFTER SUNSET.
TEMPS WILL BE ONE TO TWO CATEGORIES ABOVE NORMAL PER LOW LEVEL
THICKNESSES. MAX TEMPS NEAR 90 NW TO LOWER 90S ELSEWHERE. MIN TEMPS
70-LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 PM WEDNESDAY...
FRIDAY AND FRIDAY NIGHT: MID LEVEL SUB-TROPICAL RIDGE IS FORECAST TO
BUILD BACK NORTHWARD ON FRIDAY INTO FRIDAY NIGHT. THIS WILL HELP TO
CONTINUE TO PUSH THE MAIN MOIST AXIS BACK NORTH AND WESTWARD INTO VA
AND WESTERN NC. THUS... WILL GENERALLY LIMIT POPS TO SLIGHT CHANCE
ACROSS THE AREA... WITH THE BEST LOW END CHANCE POSSIBLY ALONG THE
SEABREEZE AND/OR FAR NORTHWEST PIEDMONT. HIGH TEMPS WILL MOSTLY TO
PARTLY SUNNY SKIES EXPECTED ARE EXPECTED TO BE IN THE LOWER 90S...
AS AFTERNOON LOW LEVEL THICKNESS ARE EXPECTED TO BE AROUND 1420/IN
THE 1420S. ANY CONVECTION THAT DEVELOP IS EXPECTED TO DIE OFF WITH
THE LOSS OF DAYTIME HEATING... WITH ANY SIGNIFICANT DISTURBANCES
CIRCLING THE SUB-TROPICAL RIDGE NORTH AND WEST OF CENTRAL NC.
THUS... EXCEPT FOR SOME HIGH CLOUDS IN THE WESTERLY UPPER LEVEL FLOW
TRAVERSING CENTRAL NC... BUT DRY CONDITIONS WITH MOSTLY CLEAR TO AT
TIMES PARTLY CLOUDY SKIES ASSOCIATED WITH THE HIGH LEVEL CLOUDS.
EXPECT LOW TEMPS WILL BE IN THE LOWER 70S AGAIN.
SATURDAY THROUGH SUNDAY: THE AFOREMENTIONED MID LEVEL RIDGE IS
EXPECTED TO BE SUPPRESSED SOUTH/EASTWARD THIS WEEKEND AS A PAIR OF
S/W DISTURBANCE TRACKING NEAR THE US./CANADIAN BORDER HELP A
MID/UPPER LEVEL TROUGH PUSH EASTWARD ACROSS THE COUNTRY AND AMPLIFY.
THIS WILL SEND AN ASSOCIATED PRE-FRONTAL TROUGH AND EVENTUALLY COLD
FRONT INTO CENTRAL NC SATURDAY AFTERNOON INTO SUNDAY. WITH A WARM
MOIST AIRMASS CHARACTERIZED BY PW`S OF AROUND 2 INCHES IN ADVANCE OF
THIS SYSTEM COUPLED WITH IMPROVING UPPER DIVERGENCE EXPECT WE SHOULD
HAVE A GOOD CHANCE FOR SHOWERS AND STORMS DURING THIS TIME FRAME.
THE BEST CHANCE FOR SATURDAY THOUGH LOOKS TO BE LATE IN THE DAY...
AND BEST CHANCES ACROSS THE NORTHWEST PIEDMONT... THEN TRANSLATING
SOUTH AND EASTWARD SATURDAY NIGHT INTO SUNDAY MORNING. A 1022-1025
MB SURFACE HIGH IS EXPECTED TO FORCEFULLY BUILD SOUTHWARD ON SUNDAY
INTO SUNDAY NIGHT FROM THE NORTH. THE BEST CHANCE FOR SHOWERS AND
STORMS BY SUNDAY AFTERNOON IS EXPECTED ACROSS THE SOUTHERN HALF OF
THE AREA. WRT A SEVERE THREAT.. SURFACE BASED CAPE VALUES ON
SATURDAY ARE EXPECTED TO BE AROUND 1000-1500 J/KG... WITH AFTERNOON
SBCAPE VALUES BEST ACROSS THE FAR SOUTH ON SUNDAY OF AROUND 1000-
2000 J/KG (DEPENDING ON WHEN THE STRONG PUSH OF COOLER AIR ARRIVES).
HOWEVER... DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL... GENERALLY
IN THE 15 TO 25 KT RANGE IN THE WARM SECTOR. THUS... THINK WE MAY
HAVE AN ISOLATED SEVERE THREAT THIS WEEKEND... BUT IT WILL
ULTIMATELY DEPEND ON THE TIMING OF THE COLD FRONT ALONG WITH ANY
POSSIBLE DISTURBANCES TRACKING ALONG IT... WITH THE MAIN THREAT OF
ISOLATED DAMAGING WIND GUSTS.
HIGH TEMPS ON SATURDAY IN ADVANCE OF THE COLD FRONT ARE EXPECTED TO
GENERALLY BE IN THE UPPER 80S TO LOWER 90S. SUNDAY... HIGHS WILL BE
TRICKY AND DEPEND ON HOW PRECIP DEVELOPS AND HOW THICK THE CLOUD
COVER IS... COUPLED WITH THE RELATED TIMING OF THE FRONT. FOR NOW
WILL TREND HIGH TEMPS DOWNWARD A BIT IN COORDINATION WITH WPC`S
TIMING/PLACEMENT OF THE FRONT. THIS YIELDS HIGH TEMPS OF AROUND 80
NORTH TO THE UPPER 80S SOUTH. LOWS TEMPS SUNDAY MORNING ARE EXPECTED
TO BE IN THE MID 60S SOUTH TO UPPER 60S/NEAR 70 SOUTH. LOWS MONDAY
MORNING... WITH POSSIBLY SOME LINGERING SHOWERS... ARE EXPECTED TO
BE IN THE LOWER TO MID 60S NORTH TO MID TO UPPER 60S SOUTH.
MONDAY THROUGH WEDNESDAY: THE SURFACE FRONT IS EXPECTED TO STALL AS
IT MOVES OFFSHORE AND ENCOUNTERS THE GULF STREAM... WITH THE
POTENTIAL FOR AN AREA OF LOW PRESSURE OR TWO TO LIFT NORTHWARD ALONG
THE FRONT. THIS WILL LEAD TO A DRIER/LESS CLOUDS NW TO LINGERING
CHANCE OF SHOWERS EAST/MORE CLOUDS... AND MUCH COOLER TEMPS AS
SURFACE HIGH PRESSURE IS EXPECTED TO CONTINUE TO EXTEND INTO CENTRAL
NC FROM THE NORTHEAST. THUS... WILL GO WITH HIGHS TEMPS GENERALLY IN
THE 70S TO LOWER 80S... AND THIS MAY EVEN BE TOO WARM. LOWS IN THE
60S.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 830 PM WEDNESDAY...
NEW THUNDERSTORMS CONTINUE TO FIRE ALONG A WELL DEFINED OUTFLOW
BOUNDARY THAT ARCS FROM TO EAST ACROSS NORTHERN PORTIONS OF THE
PIEDMONT AND COASTAL PLAIN. EXPECT BRIEF INSTANCES OF MVFR/IFR
CEILING AND VISIBILITIES IN PROXIMITY OF THE STORMS AT ALL THE
NORTHERN TAF SITES(KINT/KGSO/KRDU/KRWI). AN ISOLATED WIND GUSTS NEAR
40KTS MAY ALSO OCCUR. BULK OF CONVECTION IS EXPECTED TO DIMINISH
BY MIDNIGHT.
MAIN ISSUE AFTER MIDNIGHT...IS THE POTENTIAL FOR FOG/STRATUS
DEVELOPMENT. RAP FCST SOUNDINGS SHOW WIDESPREAD STRATUS DEVELOPING
ACROSS NORTHERN PORTIONS OF THE FORECAST AREA...IN THE NELY LOW-
LEVEL FLOW ALONG AND ON THE COOL SIDE OF A WEAK SURFACE FRONT
FORECAST TO DRIFT SOUTH INTO THE AREA. WILL HAVE IFR CEILINGS
DEVELOPING PRIOR TO SUNRISE LIFTING INTO THE LOW END VFR CATEGORY BY
16Z.
ANOTHER ROUND OF SCATTERED THUNDERSTORMS IS EXPECTED THURSDAY
AFTERNOON WITH THE GREATEST PROBABILITY OVER THE NORTHERN PIEDMONT
INCLUDING KGSO...KINT AND KRDU.
EXPECT MAINLY VFR CONDITIONS FRIDAY AND SATURDAY WITH A PERIOD OF
EARLY MORNING LOW CLOUDS AND FOG ANTICIPATED EACH DAY....AND
ISOLATED CONVECTION EACH AFTERNOON.
AN APPROACHING COLD FRONT WILL INCREASE THE THREAT FOR SCATTERED
SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PWB
NEAR TERM...PWB
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...CBL/WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
820 PM EDT WED SEP 3 2014
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST THROUGH THE FIRST HALF OF THE
WEEKEND. AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE
EACH DAY. A COLD FRONT MAY BRING AN INCREASE IN SHOWERS AND
THUNDERSTORMS FOR SUNDAY AND MONDAY. HIGH PRESSURE WILL BUILD INTO
THE REGION TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 730 PM WEDNESDAY...RIDGING SFC AND ALOFT WILL STRENGTHEN
SOME ACROSS THE AREA TONIGHT. THIS A RESULT OF THE WESTERN
ATLANTIC HIGH CONTINUING TO FLEX ITS MUSCLE ACROSS THE ILM
CWA...WITH FLOW SFC AND ALOFT FROM THE SE AND S. SOMEWHAT STABLE
LOW LEVEL MARINE LAYER HAS WORKED WELL INLAND THIS AFTN AND
TONIGHT...FURTHER THAN WHAT THE HRRR ANTICIPATED. ONE OF THE
REASONS WHY THE DEEPEST AND MORE ORGANIZED CONVECTION THIS AFTN
AND EVENING IS MAINLY LOCATED WEST OR NORTH OF THE ILM CWA. SOME
MAJOR POP RESTRUCTURING FOR THE REMAINDER OF THIS EVENING...WITH
LESS THAN ISOLATED CHANCE BY MID TO LATE THIS EVENING. INCREASED
THE FOG OUTLOOK FROM PATCHY TO AREAS...ESPECIALLY ACROSS LOCATIONS
RECEIVING THE HEAVY RAINFALL IE. NORTHERN ROBESON COUNTY. VERY
LITTLE TWEAKING NEEDED FOR OVERNIGHT TEMPS/DEWPTS AT THIS TIME
OTHER THAN WHERE PCPN OCCURRED.
PREVIOUS DISCUSSION....................................
AS OF 245 PM WEDNESDAY...ANTICIPATED CU FIELD HAS BEGUN TO DEVELOP
WITH THE FAVORED LOCATION FOR NOW OVER THE COASTAL COUNTIES.
HOWEVER...OTHER THAN A TINY SHOWER DOWN AROUND GEORGETOWN...THE
FORECAST AREA REMAINS RAIN-FREE. ANALYSIS OF MORNING SOUNDINGS
CONFIRM EARLIER FORECAST REASONING...WITH AN UNSTABLE AND MOIST
ATMOSPHERE COMBINING WITH A NUMBER OF BOUNDARIES BOTH OLD AND NEW
TO GENERATE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
STARTING LATER THIS AFTERNOON. WEAK STEERING MEANS STORM MOTION
WILL BE SLOW...LEADING TO A THREAT OF LOCALIZED FLOODING.
OTHERWISE...SOME OF THE MORE VIGOROUS STORMS COULD GENERATE STRONG
AND GUSTY WINDS LATER THIS AFTERNOON.
THE CONVECTION...BEING DIURNAL IN NATURE...WILL FADE WITH THE
SETTING SUN. ALTHOUGH A SPOT SHOWER CANNOT BE RULED OUT...EXPECT A
DRY OVERNIGHT PERIOD WITH AREAS OF FOG DEVELOPING AFTER MIDNIGHT.
CONTINUED WARM SOUTHERLY FLOW WILL KEEP OVERNIGHT TEMPERATURES A
TAD ABOVE NORMAL...WITH LOWS IN THE LOWER TO MID 70S MOST PLACES.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 245 PM...A HIGH PRESSURE RIDGE AXIS WILL BE SITUATED
JUST TO THE NORTH OF THE FORECAST AREA ON THURSDAY AND THE CENTER OF
OF THE HIGH WILL SHIFT DIRECTLY OVERHEAD BY MIDDAY FRIDAY. SO ALOFT
WINDS WILL BE FROM THE EAST AT 500 MB ON THURSDAY AND LIGHT AND
VARIABLE AT THIS LEVEL ON FRIDAY. THE PRECIPITABLE WATERS ARE
EXPECTED TO DROP BELOW 2 INCHES AND SETTLE AROUND 1.75 INCHES DURING
THE SHORT TERM PERIOD. AT THE SURFACE SOUTH TO SOUTH-SOUTHWEST WIND
FLOW WILL DOMINATED THE FORECAST. SO EXPECT WIDELY SCATTERED TO
SCATTERED CONVECTION TO DEVELOP ALONG THE SEA BREEZE AND PUSH TO THE
NORTH AND NORTHEAST OUT OF THE AREA DURING EACH DAY. MODEL SOUNDING
ARE SHOWING VERY SLOW STORM MOTIONS EACH DAY SO ANY THUNDERSTORM
ESPECIALLY INLAND THAT DEVELOPS WILL BE ABLE TO PRODUCE VERY HEAVY
RAIN.
TEMPERATURES AT 850 MB ARE SEEN TO BE COOLING IN BOTH THE 12 UTC GFS
AND NAM. THE MODELS ARE INDICATING TEMPERATURES DROPPING 2 TO 2.5
DEGREES THURSDAY AND FRIDAY. SO MAXIMUM TEMPERATURES ARE EXPECTED TO
BE A COUPLE OF DEGREES COOLER BUT STILL WARM AND MUGGY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 245 PM WEDNESDAY...EXTENDED CONTINUES TO TREND TOWARD A
RATHER UNSETTLED SCENARIO AS BROAD TROUGHING MOVING WEST TO EAST
WILL ALLOW A FRONT TO SLOWLY MOVE ACROSS THE AREA. THE FRONT
BISECTS THE AREA SUNDAY AND HENCE THE HIGHEST POPS RESIDE HERE
WITH LIKELY VALUES OVER MOST OF THE AREA. THE SLOW MOVEMENT OF THE
SYSTEM WARRANTS GOOD CHANCE VALUES FOR MONDAY WITH THE HIGHEST
VALUES NEAR THE COAST. VALUES FALL EVEN FURTHER TUESDAY AND
WEDNESDAY BUT BEING THE LAST TWO DAYS OF THE PERIOD AND THE MODELS
HINTING AT THE FRONT HANGING UP ALONG THE COAST WARRANTS AT LEAST
SOME MENTION.
TEMPERATURE FORECAST TRENDS SLOWLY LOWER THROUGH THE PERIOD WITH
SATURDAY SHOWING ONE LAST DAY OF 90S AND 70S LOWERING TO 80S AND 60S
RESPECTIVELY THE REMAINDER OF THE PERIOD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...POTENTIAL FOR MVFR/IFR DUE TO FOG LATE
OVERNIGHT/EARLY MORNING HOURS. OTHERWISE EXPECT VFR WITH A CHANCE
OF AFTERNOON SHRA/TSRA ON THURSDAY.
VFR PREVAILS ACROSS THE AREA THIS EVENING WITH SOUTH-SOUTHWEST WINDS
AROUND 5 TO 10 KTS AND SCT/BKN MID TO HIGH CLOUDS. LATEST RADAR
IMAGERY DEPICTS A FEW LIGHT SHOWERS ACROSS THE INLAND PORTIONS OF
THE AREA. THOUGH NOT CURRENTLY AFFECTING ANY TAF SITES...COULD NOT
RULE OUT THE POSSIBILITY OF A SHOWER MOVING ACROSS KFLO/KLBT OVER
THE NEXT FEW HOURS. OVERNIGHT INTO THE EARLY MORNING HOURS...SCT/BKN
CLOUDS WILL CONTINUE TO MOVE IN WITH FEW/SCT LOW STRATUS POSSIBLY
MOVING IN..ESPECIALLY INLAND...AND LIGHT WINDS. MODEL GUIDANCE
CONTINUES TO BE IN AGREEMENT WITH FOG DEVELOPMENT OVERNIGHT. THUS
HAVE KEPT WITH MVFR ALONG THE COAST...WITH MVFR/TEMPO IFR/LIFR INLAND.
ON THURSDAY...MORNING FOG WILL DISSIPATE GIVING WAY TO VFR WITH
SOUTH-SOUTHEAST WINDS INCREASING TO 10 TO 12 KTS...AND SLIGHTLY
HIGHER ALONG THE COAST. AFTERNOON SHRA/TSRA ARE POSSIBLE.
EXTENDED OUTLOOK...CHANCE OF SCATTERED AFTN SHOWERS/TSTMS THROUGH
FRIDAY. PATCHES OF MVFR/IFR FOG OR STRATUS MAY ALSO DEVELOP EACH
MORNING. A COLD FRONT DROPS INTO THE REGION SUNDAY AND MONDAY...WITH
A GOOD CHANCE FOR SHOWERS AND STORMS BOTH DAYS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 745 PM WEDNESDAY...WESTERN ATLANTIC RIDGING SFC AND ALOFT TO
PREVAIL ACROSS THE WFO ILM COASTAL WATERS. SFC PRESSURE PATTERN
OVERNIGHT TO YIELD S-SW WIND DIRECTION ILM NC WATERS...AND SE-S
ACROSS THE ILM SC WATERS. SOMEWHAT RELAXED SFC PG ACROSS THE
WATERS TO YIELD AROUND 10 KT WIND SPEEDS...EXCEPT THIS EVENING
ROUGHLY THRU MIDNIGHT WHEN THE LEFTOVER SEA BREEZE CIRCULATION TO
ADD 5 KT...IE. EVENING SPEEDS AT 10-15 KT. ISOLATED NOCTURNAL
ATL CONVECTION SHOULD REMAIN JUST OFFSHORE.
PREVIOUS DISCUSSION................................................
AS OF 245 PM WEDNESDAY...BERMUDA HIGH PRESSURE ANCHORED OVER THE
WESTERN ATLANTIC IS BRINGING SWLY WINDS IN THE 10 TO 15 KT RANGE
WITH 2 TO 3 FT SEAS OVER THE WATERS THIS AFTERNOON. EXPECT THESE
CONDITIONS TO PERSIST THROUGH THE OVERNIGHT HOURS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 PM WEDNESDAY...WITH THE BERMUDA HIGH IN PLACE SOUTHEAST TO
SOUTH WINDS WILL CONTINUE THROUGH THE SHORT TERM WITH WINDS AROUND
10 TO 15 KNOTS. SEAS AREA EXPECTED TO REMAIN GENERALLY AT OR LESS
THAN 3 FEET.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...IT APPEARS A SYNOPTIC WIND SHIFT IS IN
THE OFFING LATE SUNDAY AND CONTINUING INTO MONDAY AS A FRONT MAKES
ITS WAY ACROSS THE WATERS. WINDS WILL CONTINUE FROM THE
SOUTH/SOUTHWEST SATURDAY INTO EARLY SUNDAY AT 10-15 KNOTS.
NORTHEAST WINDS DEVELOP LATE SUNDAY BUT ARE RATHER WEAK...TEN
KNOTS OR LESS. SIGNIFICANT SEAS...BASICALLY ALL LOCAL WIND
GENERATED WAVES REMAIN TEPID IN A 2-3 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRH
NEAR TERM...DCH/REK
SHORT TERM...DRH
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
805 PM EDT WED SEP 3 2014
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST THROUGH THE FIRST HALF OF THE
WEEKEND. AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE
EACH DAY. A COLD FRONT MAY BRING AN INCREASE IN SHOWERS AND
THUNDERSTORMS FOR SUNDAY AND MONDAY. HIGH PRESSURE WILL BUILD INTO
THE REGION TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 730 PM WEDNESDAY...RIDGING SFC AND ALOFT WILL STRENGTHEN
SOME ACROSS THE AREA TONIGHT. THIS A RESULT OF THE WESTERN
ATLANTIC HIGH CONTINUING TO FLEX ITS MUSCLE ACROSS THE ILM
CWA...WITH FLOW SFC AND ALOFT FROM THE SE AND S. SOMEWHAT STABLE
LOW LEVEL MARINE LAYER HAS WORKED WELL INLAND THIS AFTN AND
TONIGHT...FURTHER THAN WHAT THE HRRR ANTICIPATED. ONE OF THE
REASONS WHY THE DEEPEST AND MORE ORGANIZED CONVECTION THIS AFTN
AND EVENING IS MAINLY LOCATED WEST OR NORTH OF THE ILM CWA. SOME
MAJOR POP RESTRUCTURING FOR THE REMAINDER OF THIS EVENING...WITH
LESS THAN ISOLATED CHANCE BY MID TO LATE THIS EVENING. INCREASED
THE FOG OUTLOOK FROM PATCHY TO AREAS...ESPECIALLY ACROSS LOCATIONS
RECEIVING THE HEAVY RAINFALL IE. NORTHERN ROBESON COUNTY. VERY
LITTLE TWEAKING NEEDED FOR OVERNIGHT TEMPS/DEWPTS AT THIS TIME
OTHER THAN WHERE PCPN OCCURRED.
PREVIOUS DISCUSSION...............................................
AS OF 245 PM WEDNESDAY...ANTICIPATED CU FIELD HAS BEGUN TO DEVELOP
WITH THE FAVORED LOCATION FOR NOW OVER THE COASTAL COUNTIES.
HOWEVER...OTHER THAN A TINY SHOWER DOWN AROUND GEORGETOWN...THE
FORECAST AREA REMAINS RAIN-FREE. ANALYSIS OF MORNING SOUNDINGS
CONFIRM EARLIER FORECAST REASONING...WITH AN UNSTABLE AND MOIST
ATMOSPHERE COMBINING WITH A NUMBER OF BOUNDARIES BOTH OLD AND NEW
TO GENERATE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
STARTING LATER THIS AFTERNOON. WEAK STEERING MEANS STORM MOTION
WILL BE SLOW...LEADING TO A THREAT OF LOCALIZED FLOODING.
OTHERWISE...SOME OF THE MORE VIGOROUS STORMS COULD GENERATE STRONG
AND GUSTY WINDS LATER THIS AFTERNOON.
THE CONVECTION...BEING DIURNAL IN NATURE...WILL FADE WITH THE
SETTING SUN. ALTHOUGH A SPOT SHOWER CANNOT BE RULED OUT...EXPECT A
DRY OVERNIGHT PERIOD WITH AREAS OF FOG DEVELOPING AFTER MIDNIGHT.
CONTINUED WARM SOUTHERLY FLOW WILL KEEP OVERNIGHT TEMPERATURES A
TAD ABOVE NORMAL...WITH LOWS IN THE LOWER TO MID 70S MOST PLACES.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 245 PM...A HIGH PRESSURE RIDGE AXIS WILL BE SITUATED
JUST TO THE NORTH OF THE FORECAST AREA ON THURSDAY AND THE CENTER OF
OF THE HIGH WILL SHIFT DIRECTLY OVERHEAD BY MIDDAY FRIDAY. SO ALOFT
WINDS WILL BE FROM THE EAST AT 500 MB ON THURSDAY AND LIGHT AND
VARIABLE AT THIS LEVEL ON FRIDAY. THE PRECIPITABLE WATERS ARE
EXPECTED TO DROP BELOW 2 INCHES AND SETTLE AROUND 1.75 INCHES DURING
THE SHORT TERM PERIOD. AT THE SURFACE SOUTH TO SOUTH-SOUTHWEST WIND
FLOW WILL DOMINATED THE FORECAST. SO EXPECT WIDELY SCATTERED TO
SCATTERED CONVECTION TO DEVELOP ALONG THE SEA BREEZE AND PUSH TO THE
NORTH AND NORTHEAST OUT OF THE AREA DURING EACH DAY. MODEL SOUNDING
ARE SHOWING VERY SLOW STORM MOTIONS EACH DAY SO ANY THUNDERSTORM
ESPECIALLY INLAND THAT DEVELOPS WILL BE ABLE TO PRODUCE VERY HEAVY
RAIN.
TEMPERATURES AT 850 MB ARE SEEN TO BE COOLING IN BOTH THE 12 UTC GFS
AND NAM. THE MODELS ARE INDICATING TEMPERATURES DROPPING 2 TO 2.5
DEGREES THURSDAY AND FRIDAY. SO MAXIMUM TEMPERATURES ARE EXPECTED TO
BE A COUPLE OF DEGREES COOLER BUT STILL WARM AND MUGGY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 245 PM WEDNESDAY...EXTENDED CONTINUES TO TREND TOWARD A
RATHER UNSETTLED SCENARIO AS BROAD TROUGHING MOVING WEST TO EAST
WILL ALLOW A FRONT TO SLOWLY MOVE ACROSS THE AREA. THE FRONT
BISECTS THE AREA SUNDAY AND HENCE THE HIGHEST POPS RESIDE HERE
WITH LIKELY VALUES OVER MOST OF THE AREA. THE SLOW MOVEMENT OF THE
SYSTEM WARRANTS GOOD CHANCE VALUES FOR MONDAY WITH THE HIGHEST
VALUES NEAR THE COAST. VALUES FALL EVEN FURTHER TUESDAY AND
WEDNESDAY BUT BEING THE LAST TWO DAYS OF THE PERIOD AND THE MODELS
HINTING AT THE FRONT HANGING UP ALONG THE COAST WARRANTS AT LEAST
SOME MENTION.
TEMPERATURE FORECAST TRENDS SLOWLY LOWER THROUGH THE PERIOD WITH
SATURDAY SHOWING ONE LAST DAY OF 90S AND 70S LOWERING TO 80S AND 60S
RESPECTIVELY THE REMAINDER OF THE PERIOD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...POTENTIAL FOR MVFR/IFR DUE TO FOG LATE
OVERNIGHT/EARLY MORNING HOURS. OTHERWISE EXPECT VFR WITH A CHANCE
OF AFTERNOON SHRA/TSRA ON THURSDAY.
VFR PREVAILS ACROSS THE AREA THIS EVENING WITH SOUTH-SOUTHWEST WINDS
AROUND 5 TO 10 KTS AND SCT/BKN MID TO HIGH CLOUDS. LATEST RADAR
IMAGERY DEPICTS A FEW LIGHT SHOWERS ACROSS THE INLAND PORTIONS OF
THE AREA. THOUGH NOT CURRENTLY AFFECTING ANY TAF SITES...COULD NOT
RULE OUT THE POSSIBILITY OF A SHOWER MOVING ACROSS KFLO/KLBT OVER
THE NEXT FEW HOURS. OVERNIGHT INTO THE EARLY MORNING HOURS...SCT/BKN
CLOUDS WILL CONTINUE TO MOVE IN WITH FEW/SCT LOW STRATUS POSSIBLY
MOVING IN..ESPECIALLY INLAND...AND LIGHT WINDS. MODEL GUIDANCE
CONTINUES TO BE IN AGREEMENT WITH FOG DEVELOPMENT OVERNIGHT. THUS
HAVE KEPT WITH MVFR ALONG THE COAST...WITH MVFR/TEMPO IFR/LIFR INLAND.
ON THURSDAY...MORNING FOG WILL DISSIPATE GIVING WAY TO VFR WITH
SOUTH-SOUTHEAST WINDS INCREASING TO 10 TO 12 KTS...AND SLIGHTLY
HIGHER ALONG THE COAST. AFTERNOON SHRA/TSRA ARE POSSIBLE.
EXTENDED OUTLOOK...CHANCE OF SCATTERED AFTN SHOWERS/TSTMS THROUGH
FRIDAY. PATCHES OF MVFR/IFR FOG OR STRATUS MAY ALSO DEVELOP EACH
MORNING. A COLD FRONT DROPS INTO THE REGION SUNDAY AND MONDAY...WITH
A GOOD CHANCE FOR SHOWERS AND STORMS BOTH DAYS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM WEDNESDAY...BERMUDA HIGH PRESSURE ANCHORED OVER THE
WESTERN ATLANTIC IS BRINGING SWLY WINDS IN THE 10 TO 15 KT RANGE
WITH 2 TO 3 FT SEAS OVER THE WATERS THIS AFTERNOON. EXPECT THESE
CONDITIONS TO PERSIST THROUGH THE OVERNIGHT HOURS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 PM WEDNESDAY...WITH THE BERMUDA HIGH IN PLACE SOUTHEAST TO
SOUTH WINDS WILL CONTINUE THROUGH THE SHORT TERM WITH WINDS AROUND
10 TO 15 KNOTS. SEAS AREA EXPECTED TO REMAIN GENERALLY AT OR LESS
THAN 3 FEET.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...IT APPEARS A SYNOPTIC WIND SHIFT IS IN
THE OFFING LATE SUNDAY AND CONTINUING INTO MONDAY AS A FRONT MAKES
ITS WAY ACROSS THE WATERS. WINDS WILL CONTINUE FROM THE
SOUTH/SOUTHWEST SATURDAY INTO EARLY SUNDAY AT 10-15 KNOTS.
NORTHEAST WINDS DEVELOP LATE SUNDAY BUT ARE RATHER WEAK...TEN
KNOTS OR LESS. SIGNIFICANT SEAS...BASICALLY ALL LOCAL WIND
GENERATED WAVES REMAIN TEPID IN A 2-3 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRH
NEAR TERM...DCH/REK
SHORT TERM...DRH
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
952 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 952 PM CDT WED SEP 3 2014
SEVERE STORMS HAVE DEVELOPED ACROSS WESTERN NORTH DAKOTA...MOSTLY
AS EXPECTED. THIS AREA OF STORMS SHOULD CONTINUE TO PROPAGATE
EASTWARD THROUGH THE OVERNIGHT HOURS. ADDITIONAL STORMS SHOULD
ALSO DEVELOP ACROSS SOUTHERN NORTH DAKOTA. GIVEN WHERE THE
STRONGEST INSTABILITY WILL BE LOCATED...THINKING THE BEST CHANCES
FOR THUNDERSTORMS (AND SEVERE THUNDERSTORMS) WILL BE ACROSS THE
SOUTHERN HALF OF THE FA. IN FACT...THE CURRENT ACTIVITY ACROSS
WESTERN NORTH DAKOTA (AT LEAST THE STRONGER REFLECTIVITIES) IS
GRADUALLY SHIFTING SOUTHWARD WITH TIME. LARGE HAIL AND STRONG WIND
GUSTS (500MB JET ABOVE 50 KTS) WILL BE THE MAIN THREATS. ADJUSTED
TIMING OF POPS BASED ON LATEST TRENDS AND HI-RES MODEL
GUIDANCE...AND KEPT THE SEVERE MENTION ACROSS THE SOUTHERN FA.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 319 PM CDT WED SEP 3 2014
CONCERN REMAINS HOW FAR NORTH CONVECTION GETS INTO SOUTHEASTERN
FCST AREA LATE THIS AFTN/EVE AND HOW MUCH CONVECTION/PRECIP
DEVELOPS IN WRN ND THIS EVE AND MOVES EAST OVERNIGHT. RAP/HRRR AND
NAM12 HAVE BEEN DOING REASONABLE IN THEIR DEPICTION OF CONVECTION
IN CNTRL MN NORTH OF THE WARM FRONT. OBS INDICATE LIKELY WARM
FRONT FROM ABOUT WATERTOWN TO CANBY MN THEN TOWARD HUTCHINSON MN
THEN TO THE TWIN CITIES. IT HAS BEEN MOVING NORTHWARD. RAP SHOWS
LOW LEVEL JET FEEDING INTO BAND OF STORMS THAT HAS BEEN SLOWLY
LIFTING NORTHEAST THRU CNTRL MN TURNING A BIT MORE SOUTHWEST TO
NORTHEAST ORIENTATION AFTER 00Z AND THUS FOCUS OF PRECIP WILL
SHIFT EAST. REGIONAL RADARS SHOWING NOW SOME DEVELOPING SOUTHWEST
OF LINE INTO THE WARM SECTOR WEST OF WILMAR..THOUGH IT IS WEAK
NOW. IDEA FROM EARLIER SWOMCD IS FOR ACTIVITY TO INCREASE IN THE
AREA NORTHWEST AND WEST OF THE TWIN CITIES NEXT FEW HOURS. IT DOES
APPEAR MORE AND MORE LIKELY THAT ONLY THE FAR SOUTHEASTERN FCST
AREA WILL HAVE ANY IMPACTS FROM THESE STORMS AND THAT MOST WILL
STAY JUST SOUTHEAST OF OUR AREA. THUS TRIMMED POPS SOME BUT DID
KEEP SEVERE MENTION AT LEAST FOR NOW INTO THE EVE IN FAR
SOUTHEASTERN FCST AREA. REST OF THE AREA DRY THRU MID EVENING.
THEN WHAT HAPPENS IS IN QUESTION. RAP SHOWS A DEVELOPING LOW LEVEL
JET AND QUITE STRONG 850 THETA-E ADVECTION AND AN AREA OF
SHOWWALTERS TO -10C MOVING NORTH INTO SE ND 06Z AND JUST
AFTERWARDS. MAIN FORCING WILL BE MORE NORTHWEST TOWARD UPPER LOW
IN SOUTHEASTERN SASK. MODELS NOT EXCITED ABOUT TOO MUCH IN THIS
ELEVATED UNSTABLE LAYER AS IT MOVES INTO SE ND OVERNIGHT BUT AREA
IS IN FAVORABLE POSITION OF LOW LEVEL JET (LEFT QUAD) AND STRONG
INSTABILITY GRADIENT SO WOULDNT BE SUPRISED IF TSTMS DEVELOP
OVERNIGHT AHD OF COLD FRONT IN A MORE WIDESPREAD FASHION THAN
MODEL ADVERTISES.
ANYHOW....DID KEEP SEVERE MENTION OVERNIGHT PER DAY 1 SLIGHT RISK
OVER CNTRL INTO SE ND AND THIS CAN BE ADJUSTED AS NEEDED. IF 850
MB SHOWWALTERS AND LOW LEVEL JET ARE ACCURATE THEN WOULD BE ENOUGH
FOR SOME SEVERE HAILERS. MU CAPES INTHE 2500 J/KG RANGE IN SE ND.
LESS INSTABILITY FARTHER NORTH BUT MAYBE A BIT BETTER CHC OF A
BAND OF SHOWERS/STORMS LATE NIGHT INTO EARLY THURSDAY. PRECIP WILL
EXIT NW MN THURSDAY AFTN...THEN DRIER AND COOLER AIR MOVES IN THU
NIGHT. THOUGH SOME WRAPAROUND CLOUD COVER PSBL ESP IN NW MN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 319 PM CDT WED SEP 3 2014
HIGH PRESSURE IN CONTROL FRIDAY WITH LIKELY DIURNAL CU WITH COOLER
AIR ALOFT.
FOR FRI NIGHT INTO TUESDAY...
A NORTHWEST FLOW PATTERN ALOFT...VOID OF ANY APPRECIABLE MOISTURE
TRANSPORT INTO THE AREA...WILL KEEP A DRY AND COOL AIR MASS IN PLACE
THROUGH THE UPCOMING WEEKEND. THE UPPER AIR PATTERN BECOMES ZONAL
SUNDAY AND TURNS TO THE SOUTHWEST SUNDAY NIGHT...WITH LEE SIDE LOW
PRESSURE MOVING INTO THE PLAINS ON MONDAY. THIS WILL OPEN UP THE
GULF FOR INCREASED MOISTURE TRANSPORT INTO THE AREA AND BRING MORE
ACTIVE WEATHER FOR THE EARLY TO MIDDLE PART OF NEXT WEEK.
TEMPERATURES WILL TYPICALLY BE RIGHT AT OR SLIGHTLY COOLER THAN
SEASONAL NORMS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 700 PM CDT WED SEP 3 2014
MVFR CIGS ACROSS KBJI AND KFAR WILL QUICKLY DISSIPATE OR MOVE EAST
THIS EVENING. THE NEXT CONCERN WILL BE THUNDER CHANCES TONIGHT.
STILL UNSURE OF EXACT COVERAGE AND INTENSITY. WILL AMEND AS
CONFIDENCE INCREASES. SOME STORMS COULD BE STRONG.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM... RIDDLE/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
918 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 916 PM CDT WED SEP 3 2014
THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA HAVE INCREASED IN
COVERAGE OVER THE PAST COUPLE HOURS. HAVE INCREASED POPS ACROSS
THE SOUTHWEST AND CENTRAL PART OF THE STATE WITH THE HRRR AND RAP
SHOWING HIGHER THUNDERSTORM CHANCES FOR THOSE LOCATIONS.
UPDATE ISSUED AT 640 PM CDT WED SEP 3 2014
ISOLATED SEVERE THUNDERSTORM CONTINUES TO TRACK EAST ACROSS
NORTHWEST NORTH DAKOTA...WITH ADDITIONAL STRONG CONVECTION OVER
NORTHEAST MONTANA. SURFACE BASED CONVECTION HAS YET TO DEVELOP
OVER WESTERN NORTH DAKOTA BUT SUCCESSIVE RUNS OF THE HRRR HAVE
INDICATED SCATTERED CONVECTION ACROSS THE SOUTHWEST AND MOVING
INTO THE SOUTH CENTRAL. LATEST RUN IS HINTING MORE AT THE
CONVECTION IN NORTHEAST MONTANA TRACKING ACROSS THE NORTHWEST AND
NORTH CENTRAL. WILL NEED TO MONITOR FOR POSSIBLE CONVECTIVE WATCH
THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHEAST MONTANA WITH
MOISTURE CONTINUING TO SLOWLY WRAP UP INTO CENTRAL NORTH DAKOTA
AHEAD OF IT. UPPER LEVEL ANALYSIS PLACES TROUGH/LOW PUSHING FORWARD
INTO EASTERN MONTANA. INITIAL WAVE EJECTING AHEAD OF THE TROUGH
CONTINUES TO PRODUCE CONVECTION OVER NORTHEAST MONTANA. FORECAST
CHALLENGES FOR TODAY INCLUDE THE SEVERE POTENTIAL LATE TODAY INTO
TONIGHT...AND THEN GUSTY WINDS ON THURSDAY.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...UPPER TROUGH WILL
CONTINUE ITS EASTWARD PUSH WITH BROAD SCALE LIFT CONTINUING TO
INCREASE FROM WEST TO EAST. MOISTURE WILL CONTINUE TO INCREASE AS
LOW SLOWLY SHIFTS TOWARDS NORTH CENTRAL SOUTH DAKOTA. INITIAL
DISCRETE STORMS THAT DEVELOP WILL ENCOUNTER INCREASING INSTABILITY
ALONG WITH IMPRESSIVE DEEP LAYER SHEAR. EXPECT INITIAL STORMS WILL
HAVE A MAINLY HAIL THREAT ALONG WITH A STRONG WIND THREAT. AS TIME
GOES ON AND STORM DEVELOPMENT WORKS EASTERLY ENCOUNTERING HIGHER
MOISTURE...THERE MAY BE A BRIEF TORNADO THREAT IF THE STORMS CAN
BE SURFACE BASED. WITH THAT SAID...THE HAIL AND WIND THREAT WILL
CONTINUE INTO THE LATE EVENING. FOCUS FOR SEVERE WILL SHIFT OVER
MAINLY CENTRAL INTO EASTERN NORTH DAKOTA OVERNIGHT AS PLUME OF
STRONG INSTABILITY REMAINS WITH STRONG THETA-E ADVECTION...WHILE
OVER THE WEST ATMOSPHERE WILL STABILIZE. STORMS SHOULD ALL BE
PUSHED OFF TO THE EAST BY SUNRISE WITH SHOWERS LINGERING.
ON THURSDAY...SOME SHOWERS WILL REMAIN PRIMARILY OVER THE NORTHERN
AND EASTERN PART OF THE STATE AS UPPER TROUGH MAKES ITS WAY EAST.
PRIMARY CONCERN WILL BE GUSTY WEST TO NORTHWESTERLY WINDS
DEVELOPING AS COLD AIR POURS INTO THE AREA WITH TIGHT PRESSURE
GRADIENT AS LOW SHIFTS INTO MINNESOTA. STRONGEST WINDS LOOK TO BE
OVER SOUTHWEST NORTH DAKOTA IN THE MORNING...WITH WINDS
DIMINISHING IN THE AFTERNOON AS GRADIENT RELAXES AND COLD AIR
ADVECTION DECREASES. TEMPERATURES WILL BE SEASONABLY COOL WITH
MANY LOCATIONS AROUND 10-15 DEGREES BELOW AVERAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
A NORTHWEST FLOW ALOFT IS MAINTAINED THURSDAY NIGHT INTO
SATURDAY...THEN TRANSITIONS TO A ZONAL FLOW SUNDAY INTO WEDNESDAY. A
MORE ACTIVE PERIOD WILL EVOLVE DURING THE ZONAL FLOW PERIOD AS A
STRONG SHORTWAVE TROUGH AND ASSOCIATED POTENT COLD FRONT IS SLATED
TO SWEEP THROUGH TUESDAY INTO WEDNESDAY...WITH SEVERE WEATHER POSSIBLE.
GUSTY NORTHWEST WINDS THURSDAY EVENING WILL QUICKLY SUBSIDE AS A
SURFACE HIGH PRESSURE SLIDES ACROSS SOUTHWEST NORTH DAKOTA EARLY
THURSDAY NIGHT AND INTO CENTRAL SOUTH DAKOTA BY 12Z FRIDAY. A CLEAR
SKY...GOOD RADIATIONAL COOLING...AND DEWPOINTS IN THE UPPER 30S LOOK
REASONABLE TO SUPPORT OVERNIGHT LOWS IN THE UPPER 30S ACROSS THE
SOUTHWEST...ESPECIALLY OVER THE NORMAL COLDER LOCATIONS SUCH AS
HETTINGER. HENCE HAVE LOWERED MINIMUM TEMPERATURES INTO THE UPPER
30S UNDER THIS WEATHER PATTERN. OVERALL...A QUIET/PLEASANT WEATHER
PATTERN CONTINUES FRIDAY/SATURDAY WITH A SLOW MODERATING TREND. H85
TEMPS BEGIN TO WARM LEADING TO HIGHS INTO THE 70S SATURDAY AND
SUNDAY. THERE WILL BE A SUBTLE DRY COLD FRONTAL PASSAGE SATURDAY
AFTERNOON...HOWEVER OTHER THAN A WINDSHIFT TO THE NORTHWEST...NOT
EXPECTING MUCH OF A TEMPERATURE CHANGE.
A MORE ACTIVE WEATHER PATTERN SLOWLY BEGINS TO EMERGE SUNDAY NIGHT
AS A WEAK SHORTWAVE SLIDES THROUGH WITH WARM AIR ADVECTION PROCESSES
TAKING OVER. A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS ARE POSSIBLE
SUNDAY NIGHT INTO MONDAY MAINLY FOR THE JAMES RIVER VALLEY. THE
WARMEST DAY WILL BE MONDAY WITH HIGHS REACHING BETWEEN 75 AND 85.
THIS WILL BE FOLLOWED BY A STRONG COLD FRONT WHICH WILL APPROACH
NORTHWEST NORTH DAKOTA TUESDAY MORNING AND THEN SWEEP THROUGH
TUESDAY AFTERNOON/EVENING. A STRONG H85 BAROCLINIC ZONE SHIFTS
THROUGH TUESDAY NIGHT WITH THE 0C TO -2C ISOTHERM SETTLING INTO
CENTRAL NORTH DAKOTA WEDNESDAY. THIS TREND SETS THE STAGE FOR MUCH
COLDER AIR WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 640 PM CDT WED SEP 3 2014
SCATTERED CONVECTION THIS EVENING ACROSS WESTERN AND CENTRAL NORTH
DAKOTA AS A COLD FRONT MOVES THROUGH THE AREA. FLOW WILL TURN
WEST TO NORTHWEST LATE TONIGHT AND THURSDAY WITH AREAS OF MVFR
CLOUDINESS...ESPECIALLY ACROSS THE NORTH...KISN TO KMOT. STRONG
NORTHWEST WINDS ON THURSDAY WITH THE STRONGEST 20 TO 35 MPH AT KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 AM TO 4 PM MDT THURSDAY FOR NDZ031>033-040-
041-043-044.
&&
$$
UPDATE...CK
SHORT TERM...JJS
LONG TERM...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
700 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 700 PM CDT WED SEP 3 2014
THE REGION SHOULD REMAIN DRY UNTIL LATER TONIGHT (850MB JET AND
WARM FRONTAL THUNDERSTORMS WILL CONTINUE TO SHIFT EAST THROUGH
INTO NORTHERN WISCONSIN). REMOVED POPS UNTIL CLOSER TO MIDNIGHT.
FOCUS SHIFTS TO THE WEST...WHERE A SEVERE STORM ACROSS NORTH
CENTRAL NORTH DAKOTA IS MOVING TOWARD EASTERN NORTH DAKOTA. HI-RES
MODEL GUIDANCE MOSTLY INDICATES THAT THIS COMPLEX WILL HOLD
TOGETHER FOR MUCH OF THE NIGHT (THROUGH THE NORTHERN FA)...BUT
WILL LOSE INTENSITY AS IT PROPAGATES INTO THE DEVILS LAKE BASIN.
THIS MAKES SOME SENSE IF IT OUTRUNS THE STRONG FORCING BEING
SUPPLIED FROM THE UPPER LOW. AFTER MIDNIGHT...ANOTHER AREA OF
STORMS ASSOCIATED WITH A NORTHWARD LIFTING ELEVATED WARM FRONT
(AND FORCING FROM THE APPROACHING UPPER LOW) SHOULD DEVELOP ACROSS
THE SOUTHERN FA. THIS AREA OF STORMS WILL HAVE STRONG INSTABILITY
TO WORK WITH...AND DECENT DEEP LAYER SHEAR. THUS...STRONG TO
SEVERE STORMS ARE HIGHLY POSSIBLE (MAIN THREAT LIKELY LARGE
HAIL...AND POSSIBLY STRONG WINDS). ADJUSTED THE SEVERE MENTION IN
OUR FORECAST TO THE ABOVE THINKING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 319 PM CDT WED SEP 3 2014
CONCERN REMAINS HOW FAR NORTH CONVECTION GETS INTO SOUTHEASTERN
FCST AREA LATE THIS AFTN/EVE AND HOW MUCH CONVECTION/PRECIP
DEVELOPS IN WRN ND THIS EVE AND MOVES EAST OVERNIGHT. RAP/HRRR AND
NAM12 HAVE BEEN DOING REASONABLE IN THEIR DEPICTION OF CONVECTION
IN CNTRL MN NORTH OF THE WARM FRONT. OBS INDICATE LIKELY WARM
FRONT FROM ABOUT WATERTOWN TO CANBY MN THEN TOWARD HUTCHINSON MN
THEN TO THE TWIN CITIES. IT HAS BEEN MOVING NORTHWARD. RAP SHOWS
LOW LEVEL JET FEEDING INTO BAND OF STORMS THAT HAS BEEN SLOWLY
LIFTING NORTHEAST THRU CNTRL MN TURNING A BIT MORE SOUTHWEST TO
NORTHEAST ORIENTATION AFTER 00Z AND THUS FOCUS OF PRECIP WILL
SHIFT EAST. REGIONAL RADARS SHOWING NOW SOME DEVELOPING SOUTHWEST
OF LINE INTO THE WARM SECTOR WEST OF WILMAR..THOUGH IT IS WEAK
NOW. IDEA FROM EARLIER SWOMCD IS FOR ACTIVITY TO INCREASE IN THE
AREA NORTHWEST AND WEST OF THE TWIN CITIES NEXT FEW HOURS. IT DOES
APPEAR MORE AND MORE LIKELY THAT ONLY THE FAR SOUTHEASTERN FCST
AREA WILL HAVE ANY IMPACTS FROM THESE STORMS AND THAT MOST WILL
STAY JUST SOUTHEAST OF OUR AREA. THUS TRIMMED POPS SOME BUT DID
KEEP SEVERE MENTION AT LEAST FOR NOW INTO THE EVE IN FAR
SOUTHEASTERN FCST AREA. REST OF THE AREA DRY THRU MID EVENING.
THEN WHAT HAPPENS IS IN QUESTION. RAP SHOWS A DEVELOPING LOW LEVEL
JET AND QUITE STRONG 850 THETA-E ADVECTION AND AN AREA OF
SHOWWALTERS TO -10C MOVING NORTH INTO SE ND 06Z AND JUST
AFTERWARDS. MAIN FORCING WILL BE MORE NORTHWEST TOWARD UPPER LOW
IN SOUTHEASTERN SASK. MODELS NOT EXCITED ABOUT TOO MUCH IN THIS
ELEVATED UNSTABLE LAYER AS IT MOVES INTO SE ND OVERNIGHT BUT AREA
IS IN FAVORABLE POSITION OF LOW LEVEL JET (LEFT QUAD) AND STRONG
INSTABILITY GRADIENT SO WOULDNT BE SUPRISED IF TSTMS DEVELOP
OVERNIGHT AHD OF COLD FRONT IN A MORE WIDESPREAD FASHION THAN
MODEL ADVERTISES.
ANYHOW....DID KEEP SEVERE MENTION OVERNIGHT PER DAY 1 SLIGHT RISK
OVER CNTRL INTO SE ND AND THIS CAN BE ADJUSTED AS NEEDED. IF 850
MB SHOWWALTERS AND LOW LEVEL JET ARE ACCURATE THEN WOULD BE ENOUGH
FOR SOME SEVERE HAILERS. MU CAPES INTHE 2500 J/KG RANGE IN SE ND.
LESS INSTABILITY FARTHER NORTH BUT MAYBE A BIT BETTER CHC OF A
BAND OF SHOWERS/STORMS LATE NIGHT INTO EARLY THURSDAY. PRECIP WILL
EXIT NW MN THURSDAY AFTN...THEN DRIER AND COOLER AIR MOVES IN THU
NIGHT. THOUGH SOME WRAPAROUND CLOUD COVER PSBL ESP IN NW MN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 319 PM CDT WED SEP 3 2014
HIGH PRESSURE IN CONTROL FRIDAY WITH LIKELY DIURNAL CU WITH COOLER
AIR ALOFT.
FOR FRI NIGHT INTO TUESDAY...
A NORTHWEST FLOW PATTERN ALOFT...VOID OF ANY APPRECIABLE MOISTURE
TRANSPORT INTO THE AREA...WILL KEEP A DRY AND COOL AIR MASS IN PLACE
THROUGH THE UPCOMING WEEKEND. THE UPPER AIR PATTERN BECOMES ZONAL
SUNDAY AND TURNS TO THE SOUTHWEST SUNDAY NIGHT...WITH LEE SIDE LOW
PRESSURE MOVING INTO THE PLAINS ON MONDAY. THIS WILL OPEN UP THE
GULF FOR INCREASED MOISTURE TRANSPORT INTO THE AREA AND BRING MORE
ACTIVE WEATHER FOR THE EARLY TO MIDDLE PART OF NEXT WEEK.
TEMPERATURES WILL TYPICALLY BE RIGHT AT OR SLIGHTLY COOLER THAN
SEASONAL NORMS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 700 PM CDT WED SEP 3 2014
MVFR CIGS ACROSS KBJI AND KFAR WILL QUICKLY DISSIPATE OR MOVE EAST
THIS EVENING. THE NEXT CONCERN WILL BE THUNDER CHANCES TONIGHT.
STILL UNSURE OF EXACT COVERAGE AND INTENSITY. WILL AMEND AS
CONFIDENCE INCREASES. SOME STORMS COULD BE STRONG.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM... RIDDLE/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
639 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 640 PM CDT WED SEP 3 2014
ISOLATED SEVERE THUNDERSTORM CONTINUES TO TRACK EAST ACROSS
NORTHWEST NORTH DAKOTA...WITH ADDITIONAL STRONG CONVECTION OVER
NORTHEAST MONTANA. SURFACE BASED CONVECTION HAS YET TO DEVELOP
OVER WESTERN NORTH DAKOTA BUT SUCCESSIVE RUNS OF THE HRRR HAVE
INDICATED SCATTERED CONVECTION ACROSS THE SOUTHWEST AND MOVING
INTO THE SOUTH CENTRAL. LATEST RUN IS HINTING MORE AT THE
CONVECTION IN NORTHEAST MONTANA TRACKING ACROSS THE NORTHWEST AND
NORTH CENTRAL. WILL NEED TO MONITOR FOR POSSIBLE CONVECTIVE WATCH
THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHEAST MONTANA WITH
MOISTURE CONTINUING TO SLOWLY WRAP UP INTO CENTRAL NORTH DAKOTA
AHEAD OF IT. UPPER LEVEL ANALYSIS PLACES TROUGH/LOW PUSHING FORWARD
INTO EASTERN MONTANA. INITIAL WAVE EJECTING AHEAD OF THE TROUGH
CONTINUES TO PRODUCE CONVECTION OVER NORTHEAST MONTANA. FORECAST
CHALLENGES FOR TODAY INCLUDE THE SEVERE POTENTIAL LATE TODAY INTO
TONIGHT...AND THEN GUSTY WINDS ON THURSDAY.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...UPPER TROUGH WILL
CONTINUE ITS EASTWARD PUSH WITH BROAD SCALE LIFT CONTINUING TO
INCREASE FROM WEST TO EAST. MOISTURE WILL CONTINUE TO INCREASE AS
LOW SLOWLY SHIFTS TOWARDS NORTH CENTRAL SOUTH DAKOTA. INITIAL
DISCRETE STORMS THAT DEVELOP WILL ENCOUNTER INCREASING INSTABILITY
ALONG WITH IMPRESSIVE DEEP LAYER SHEAR. EXPECT INITIAL STORMS WILL
HAVE A MAINLY HAIL THREAT ALONG WITH A STRONG WIND THREAT. AS TIME
GOES ON AND STORM DEVELOPMENT WORKS EASTERLY ENCOUNTERING HIGHER
MOISTURE...THERE MAY BE A BRIEF TORNADO THREAT IF THE STORMS CAN
BE SURFACE BASED. WITH THAT SAID...THE HAIL AND WIND THREAT WILL
CONTINUE INTO THE LATE EVENING. FOCUS FOR SEVERE WILL SHIFT OVER
MAINLY CENTRAL INTO EASTERN NORTH DAKOTA OVERNIGHT AS PLUME OF
STRONG INSTABILITY REMAINS WITH STRONG THETA-E ADVECTION...WHILE
OVER THE WEST ATMOSPHERE WILL STABILIZE. STORMS SHOULD ALL BE
PUSHED OFF TO THE EAST BY SUNRISE WITH SHOWERS LINGERING.
ON THURSDAY...SOME SHOWERS WILL REMAIN PRIMARILY OVER THE NORTHERN
AND EASTERN PART OF THE STATE AS UPPER TROUGH MAKES ITS WAY EAST.
PRIMARY CONCERN WILL BE GUSTY WEST TO NORTHWESTERLY WINDS
DEVELOPING AS COLD AIR POURS INTO THE AREA WITH TIGHT PRESSURE
GRADIENT AS LOW SHIFTS INTO MINNESOTA. STRONGEST WINDS LOOK TO BE
OVER SOUTHWEST NORTH DAKOTA IN THE MORNING...WITH WINDS
DIMINISHING IN THE AFTERNOON AS GRADIENT RELAXES AND COLD AIR
ADVECTION DECREASES. TEMPERATURES WILL BE SEASONABLY COOL WITH
MANY LOCATIONS AROUND 10-15 DEGREES BELOW AVERAGE.
LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 221 PM
CDT WED SEP 3 2014
A NORTHWEST FLOW ALOFT IS MAINTAINED THURSDAY NIGHT INTO
SATURDAY...THEN TRANSITIONS TO A ZONAL FLOW SUNDAY INTO WEDNESDAY. A
MORE ACTIVE PERIOD WILL EVOLVE DURING THE ZONAL FLOW PERIOD AS A
STRONG SHORTWAVE TROUGH AND ASSOCIATED POTENT COLD FRONT IS SLATED
TO SWEEP THROUGH TUESDAY INTO WEDNESDAY...WITH SEVERE WEATHER POSSIBLE.
GUSTY NORTHWEST WINDS THURSDAY EVENING WILL QUICKLY SUBSIDE AS A
SURFACE HIGH PRESSURE SLIDES ACROSS SOUTHWEST NORTH DAKOTA EARLY
THURSDAY NIGHT AND INTO CENTRAL SOUTH DAKOTA BY 12Z FRIDAY. A CLEAR
SKY...GOOD RADIATIONAL COOLING...AND DEWPOINTS IN THE UPPER 30S LOOK
REASONABLE TO SUPPORT OVERNIGHT LOWS IN THE UPPER 30S ACROSS THE
SOUTHWEST...ESPECIALLY OVER THE NORMAL COLDER LOCATIONS SUCH AS
HETTINGER. HENCE HAVE LOWERED MINIMUM TEMPERATURES INTO THE UPPER
30S UNDER THIS WEATHER PATTERN. OVERALL...A QUIET/PLEASANT WEATHER
PATTERN CONTINUES FRIDAY/SATURDAY WITH A SLOW MODERATING TREND. H85
TEMPS BEGIN TO WARM LEADING TO HIGHS INTO THE 70S SATURDAY AND
SUNDAY. THERE WILL BE A SUBTLE DRY COLD FRONTAL PASSAGE SATURDAY
AFTERNOON...HOWEVER OTHER THAN A WINDSHIFT TO THE NORTHWEST...NOT
EXPECTING MUCH OF A TEMPERATURE CHANGE.
A MORE ACTIVE WEATHER PATTERN SLOWLY BEGINS TO EMERGE SUNDAY NIGHT
AS A WEAK SHORTWAVE SLIDES THROUGH WITH WARM AIR ADVECTION PROCESSES
TAKING OVER. A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS ARE POSSIBLE
SUNDAY NIGHT INTO MONDAY MAINLY FOR THE JAMES RIVER VALLEY. THE
WARMEST DAY WILL BE MONDAY WITH HIGHS REACHING BETWEEN 75 AND 85.
THIS WILL BE FOLLOWED BY A STRONG COLD FRONT WHICH WILL APPROACH
NORTHWEST NORTH DAKOTA TUESDAY MORNING AND THEN SWEEP THROUGH
TUESDAY AFTERNOON/EVENING. A STRONG H85 BAROCLINIC ZONE SHIFTS
THROUGH TUESDAY NIGHT WITH THE 0C TO -2C ISOTHERM SETTLING INTO
CENTRAL NORTH DAKOTA WEDNESDAY. THIS TREND SETS THE STAGE FOR MUCH
COLDER AIR WEDNESDAY THROUGH FRIDAY.
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1216 PM CDT WED SEP 3 2014
A COLD FRONT WILL MOVE THROUGH THE AREA LATE TODAY INTO TONIGHT
BRINGING SCATTERED TO NUMEROUS SHRA/TSRA. SOME OF THESE STORMS
WILL HAVE THE POTENTIAL TO BECOME SEVERE. LATE TONIGHT INTO EARLY
THURSDAY...MVFR/IFR CIGS ARE EXPECTED TO DEVELOP. ALSO...GUSTY
NORTHWEST WINDS ARE EXPECTED TO DEVELOP...PARTICULARLY OVER
SOUTHWEST NORTH DAKOTA.
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 640 PM CDT WED SEP 3 2014
SCATTERED CONVECTION THIS EVENING ACROSS WESTERN AND CENTRAL NORTH
DAKOTA AS A COLD FRONT MOVES THROUGH THE AREA. FLOW WILL TURN
WEST TO NORTWEST LATE TONIGHT AND THURSDAY WITH AREAS OF MVFR
CLOUDINESS...ESPECIALLY ACROSS THE NORTH...KISN TO KMOT. STRONG
NORTHWEST WINDS ON THURSDAY WITH THE STRONGEST 20 TO 35 MPH AT KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 AM TO 4 PM MDT THURSDAY FOR NDZ031>033-040-
041-043-044.
&&
$$
UPDATE...TWH
SHORT TERM...JJS
LONG TERM/AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1225 AM CDT TUE SEP 2 2014
.UPDATE...
ISSUED AT 1225 AM CDT TUE SEP 2 2014
ONLY MINOR TWEAKS WERE MADE TO THE ONGOING FORECAST.
CANADIAN RADAR SHOWS SCATTERED SHOWERS MOVING SOUTHEAST ACROSS THE
CANADIAN PRAIRIES. THE LATEST RUN OF THE HRRR (03 UTC) PICKS UP ON
THE CANADIAN ACTIVITY AND BRINGS A FEW ISOLATED SHOWERS ACROSS
THE NORTH THROUGH THE EARLY MORNING HOURS. UPDATED THE PRECIP
FORECAST TO REFLECT THE LATEST TRENDS.
LATEST TEMPERATURE OBSERVATIONS WERE NEARING OVERNIGHT FORECAST LOWS
ALREADY. WITH SEVERAL HOURS OF DIURNAL COOLING AHEAD...LOWERED THE
OVERNIGHT LOWS A FEW MORE DEGREES.
UPDATE ISSUED AT 938 PM CDT MON SEP 1 2014
SCATTERED/ISOLATED SHOWERS AND THUNDERSTORMS HAVE DIMINISHED OVER
THE LAST HOUR WITH THE LOSS OF DAYTIME HEATING. REMOVED EVENING
POPS FROM THE FORECAST AS A RESULT. ALSO ADJUSTED THE HOURLY
TEMP/DEWPOINT GRIDS BASED ON CURRENT OBS/TRENDS. THE UPDATED
PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 604 PM CDT MON SEP 1 2014
ISOLATED TO SCATTERED INSTABILITY SHOWERS AND THUNDERSTORMS WILL
CONTINUE TO DEVELOP THROUGH THE EARLY EVENING HOURS...MAINLY OVER
WESTERN NORTH DAKOTA. WITH VERY WEAK DEEP LAYER SHEAR IN
PLACE...THIS CONVECTION IS EXPECTED TO BE BRIEF AND SUB-SEVERE. IT
SHOULD END BY 03Z THIS EVENING...IF NOT SOONER.
AFTER MIDNIGHT...THE MESOSCALE MODELS PROG A WEAK WAVE AND
ATTENDANT LIGHT QPF TO SKIRT ACROSS THE CANADIAN BORDER COUNTIES.
AS A RESULT...WILL MAINTAIN SLIGHT CHANCE POPS ACROSS THE
EXTREME NORTHERN CWA AFTER MIDNIGHT. CONVECTION SHOULD BE BRIEF
AND REMAIN SUB-SEVERE IF IT EVEN MATERIALIZES.
OTHERWISE...JUST MADE A FEW COSMETIC ADJUSTMENTS TO THE HOURLY
SENSIBLE WEATHER GRIDS. THE UPDATED PRODUCTS WILL BE OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 247 PM CDT MON SEP 1 2014
CURRENT SURFACE ANALYSIS PLACES LOW OVER ONTARIO WITH HIGH OVER
THE PACIFIC NORTHWEST INTO THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS PLACES BROAD TROUGH CENTERED OVER THE PLAINS WORKING
TOWARDS THE MIDWEST. MODEST SHORT WAVE WORKING THROUGH THE FLOW
NOW MAKING ITS WAY FROM EASTERN MONTANA INTO THE WESTERN DAKOTAS
STARTING TO PRODUCE SOME CONVECTION.
FOR THE REST OF THIS AFTERNOON INTO THIS EVENING...EXPECT SOME
SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP THROUGH THE
AFTERNOON. EXPECT ANY ACTIVITY SHOULD REMAIN ON THE TAME SIDE WITH
WEAK INSTABILITY/SHEAR. MOST ACTIVITY SHOULD COME TO AN END THIS
EVENING WITH DIMINISHING INSOLATION...THOUGH SOME SHOWERS/STORMS
MAY LINGER THROUGH THE OVERNIGHT OVER FAR NORTHERN NORTH DAKOTA AS
ANOTHER WAVE MAKES ITS WAY THROUGH.
ON TUESDAY...A FEW SHOWERS/STORMS MAY CONTINUE OVER THE FAR NORTH
AS AFOREMENTIONED WAVE CONTINUES TO MAKE ITS WAY THROUGH. OTHERWISE
A QUIET DAY IS ON TAP AS LOW AMPLITUDE RIDGE STARTS TO WORK ITS
WAY INTO THE AREA. SLIGHTLY MILDER TEMPS ARE EXPECTED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 247 PM CDT MON SEP 1 2014
THE EXTENDED MODEL SUITE IS IN GOOD AGREEMENT WITH A POSITIVELY
TILTED SHORTWAVE TROUGH CURRENTLY LOCATED/ELONGATED FROM 140W/60N
TO 150W/55N...TO SHIFT INLAND TUESDAY NIGHT. THIS TROUGH IS
FORECAST TO REMAIN NEUTRAL TO SLIGHTLY NEGATIVE TILTED AS IT
SLIDES ACROSS WESTERN AND CENTRAL NORTH DAKOTA WEDNESDAY
NIGHT/THURSDAY MORNING. THIS WILL BE THE TIME PERIOD WITH THE
HIGHEST POPS...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
HEAVIEST RAINFALL APPEARS TO OCCUR OVER NORTH CENTRAL NORTH DAKOTA
WITH AROUND 0.65 INCHES FORECAST FROM MOHALL TO STANLEY...AND FROM
MINOT TO NEAR GARRISON. NAM/GFS SOUNDINGS SHOW A STRONG CAP IN
PLACE THROUGH 00Z THURSDAY FOR KMOT/KBIS/KJMS...AND A WEAKER CAP
IN PLACE AT KISN/KDIK. HAVE CONFINED POPS TO MAINLY THE NORTHWEST
AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WEDNESDAY...WITH
SHOWERS AND THUNDERSTORMS INCREASING IN COVERAGE WEDNESDAY
EVENING AND NIGHT. A POTENT COLD FRONT SWEEPS THROUGH WEDNESDAY
NIGHT WITH THE UPPER TROUGH APPROACHING AND SLIDING THROUGH ON
THURSDAY. SPC HAS A SEE TEXT WHICH INCLUDES NORTH DAKOTA...HOWEVER
LIMITED LOW LEVEL MOISTURE PER AN EAST TO SOUTHEASTERLY FLOW MAY
INHIBIT ORGANIZED SEVERE THUNDERSTORMS FROM DEVELOPING. HOWEVER
STRONG 0-6KM SHEAR OF 55KT TO 60KT WILL BE IN PLACE AHEAD OF THE
UPPER TROUGH AND ALONG/AHEAD OF THE SURFACE COLD FRONT. THIS WILL BE
MONITORED CLOSELY.
STRONG COOLING AS THE H85 FRONT SLIDES THROUGH...WITH TEMPS COOLING
FROM AROUND +20C WEDNESDAY EVENING...TO +6C THURSDAY EVENING. EXPECT
THE GREATEST WARMTH TO OCCUR ACROSS SOUTHERN NORTH DAKOTA WEDNESDAY
AFTERNOON ALONG/AHEAD OF THE H85 THERMAL RIDGE AXIS. EXPECT HIGHS IN
THE LOWER 80S. THIS WILL BE REPLACED WITH WIDESPREAD HIGHS IN THE
60S...EXCEPT LOWER 70S IN THE FAR SOUTHERN JAMES RIVER VALLEY
THURSDAY. BREEZY NORTHWEST WINDS OF 15 TO 25 MPH WILL ALSO
MATERIALIZE BEHIND THE FRONT FOR THURSDAY. WITH THE UPPER TROUGH
SWINGING THROUGH THURSDAY...STILL EXPECT A CHANCE FOR SHOWERS AND
THUNDERSHOWERS MAINLY ACROSS THE NORTH.
THEREAFTER...FRIDAY THROUGH SUNDAY...DRY WEATHER WITH A SLOW
MODERATING TREND AS BROAD CYCLONIC NORTHWEST FLOW DOMINATES THROUGH
SATURDAY. THIS TRANSITIONS TO BROAD RIDGING SUNDAY AND HIGHS WARMING
INTO THE MID 70S. A SLIGHT CHANCE OF THUNDERSTORMS COULD RETURN BY
MONDAY BUT THE BETTER CHANCES ARRIVE TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1225 AM CDT TUE SEP 2 2014
VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS THROUGH THE TAF
PERIOD WITH PREDOMINATELY WEST SOUTHWEST WINDS AND SCATTERED HIGH
CLOUDS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AJ
SHORT TERM...JJS
LONG TERM...KS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1247 PM EDT TUE SEP 2 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE AREA TODAY EXTENDING FROM LOW
PRESSURE TRACKING NORTHEAST ACROSS QUEBEC. HIGH PRESSURE WILL
EXPAND OVER THE OHIO VALLEY TONIGHT...THEN TO THE EAST COAST ON
WEDNESDAY. A WARM FRONT WILL LIFT NORTH ON THURSDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM THAT WILL PASS NORTH OF THE GREAT LAKES
ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LINE OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS PUSHING INTO
NORTHWEST OHIO AT THIS TIME WITH THE COLD FRONT. STILL EXPECTING
SOME SUN BEHIND THE FRONT ONCE IT MOVES THROUGH THE REGION.
DECIDED TO BUMP TEMPERATURES DOWN A FEW DEGREES DUE TO EXTENSIVE
CLOUD COVER AND COOL AIR ADVECTION BEHIND THE FRONT.
OTHERWISE...NO SIGNIFICANT CHANGES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE WILL EXPAND EASTWARD ACROSS THE OHIO VALLEY TONIGHT.
IT LOOKS LIKE A WEAK THERMAL TROUGH WILL LINGER OVER LAKE ERIE ON
THE NORTH SIDE OF THE HIGH THIS EVENING AND MAY PROVIDE ENOUGH
CONVERGENCE FOR A FEW SHOWERS TO DEVELOP OVER THE LAKE. LEFT A LOW
POP BOTH OVER THE LAKE AND ALONG THE EASTERN LAKESHORE FOR A PORTION
OF THE NIGHT. INLAND AREAS...ESPECIALLY OUR SOUTHERN COUNTIES COULD
SEE SOME FOG OR STRATUS GIVEN THE LINGERING BOUNDARY LAYER MOISTURE
COUPLED WITH CLEARING SKIES AND LIGHT WINDS. TEMPERATURES WILL
BOTTOM OUT IN THE UPPER 50S TO LOW 60S.
THE AIR MASS DOES NOT COOL MUCH WITH THE FRONTAL PASSAGE AND
TEMPERATURES ARE STILL EXPECTED TO BE A COUPLE DEGREES ABOVE NORMAL
ON WEDNESDAY. THE MAIN DIFFERENCE WILL BE FELT IN THE HUMIDITY WHICH
WILL BE LOWER AND MORE PLEASANT WITH DEW POINTS NEAR 60 DEGREES.
MAINLY JUST SCATTERED CU ON WEDNESDAY ONCE ANY MORNING CLOUDS BURN
OFF.
HEIGHTS WILL REBOUND OVER THE AREA ON THURSDAY AND A WARM FRONT WILL
LIFT NORTH AHEAD OF THE NEXT LOW PRESSURE SYSTEM TRACKING OUT OF THE
PLAINS. THIS SYSTEM IS FORECAST TO TRACK ACROSS LAKE SUPERIOR THEN
CONTINUE NORTHEAST ACROSS ONTARIO AND QUEBEC. ENOUGH DRY AIR SHOULD
STILL BE IN PLACE ON THURSDAY FOR THE FORECAST AREA TO STAY DRY.
LEFT THE 20 POP IN THE FORECAST ON THURSDAY NIGHT AS MOISTURE DOES
START TO INCREASE ALTHOUGH THE MORE FOCUSED MOISTURE ADVECTION WILL
BE WELL TO THE NORTH. THE ASSOCIATED COLD FRONT WILL SINK SOUTH
TOWARDS THE AREA ON FRIDAY. LOWERED POPS DURING THE MORNING HOURS
AND ACROSS THE SOUTHERN COUNTIES THAT SHOULD STRUGGLE TO SEE ANY
PRECIPITATION UNTIL FRIDAY NIGHT. TEMPERATURES ON THURSDAY AND
FRIDAY WILL BE IN THE MID 80S...WITH A FEW SPOTS MAKING A RUN AT THE
UPPER 80S.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NO BIG CHANGES TO THE MODELS FOR THE EXTENDED WITH GUIDANCE SHOWING
A COLD FRONT TO OUR SOUTH SATURDAY MORNING WITH DRIER AIR AND HIGH
MOVING IN FROM THE NORTH. DONT THINK THE DAY WILL BEGIN DRY HOWEVER
AS THE ECMWF REMAINS SLOWER THAN THE GFS IN MOVING MOISTURE OUT OF
THE AREA. WILL CONTINUE WITH CHANCE POPS THROUGH THE MORNING
SATURDAY BEFORE DROPPING TO A SLIGHT CHANCE ACROSS THE NORTH.
SATURDAY NIGHT THROUGH MONDAY LOOK DRY. TEMPS NEAR NORMAL AFTER AN
ABOVE NORMAL END TO THE WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
WEAK COLD FRONT TO OUR NORTHWEST NR A KFNT-KSBN LINE. FROM WILL
MOVE THROUGH THE AREA DURING THE DAY. CONVECTION FROM INDIANA
TRACKING ENE ACROSS CENTRAL AND SRN OHIO. WILL LIKELY SEE THUNDER
INTO NRN OHIO BUT KEPT MENTION OUT OF THE FAR NRN TAFS. HRRR MOVES
THIS PRECIP THROUGH DURING THE MORNING AND EARLY AFTERNOON WITH
POSSIBLY A FEW LINGERING SHOWERS FOR MID AFTERNOON. EXPECT MAINLY
MVFR CONDITIONS WITH AND JUST BEHIND THE PRECIP...LIFTING TO VFR 2
TO 4 HOURS AFTER PRECIP ENDS. EXPECT THE EVENING WILL BEGIN VFR
HOWEVER WITH LOW LEVEL MOISTURE IN PLACE...DRYING ALOFT AND HIGH
PRESSURE OVER THE AREA EXPECT MVFR AND POSSIBLY IFR CIGS/FOG TO
DEVELOP OVERNIGHT.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
WILL BEGIN TODAY CLOSE TO SMALL CRAFT CRITERIA MAINLY EAST OF
CONNEAUT BUT FOR NOW WILL CONTINUE WITH A FORECAST JUST BELOW. WINDS
TODAY WILL BE FROM THE SOUTHWEST AHEAD OF A WEAK COLD FRONT DUE IN
LATE MORNING/EARLY AFTERNOON. WINDS WILL TURN WEST TO BRIEFLY
NORTHWEST BEHIND THE BOUNDARY. HIGH PRESSURE BUILDS IN TONIGHT AND
WEDNESDAY. THURSDAY THE HIGH WILL DRIFT EAST AND A LOW WILL BE
MOVING THROUGH THE NORTHERN PLAINS. THIS WILL AGAIN SETUP SOUTHWEST
FLOW ON THE LAKE THURSDAY INCREASING TO 10 TO 20 KNOTS. THE LOW WILL
MOVE THROUGH EASTERN CANADA FRIDAY DRAGGING A COLD FRONT ACROSS THE
LAKE DURING THE AFTERNOON. WINDS WILL TURN NORTHWEST FRIDAY NIGHT
AND SATURDAY BEHIND THE FRONT. ALTHOUGH CLOSE...NO NEAR TERM
HEADLINES FOR NOW. FRIDAY INTO SATURDAY WE COULD REACH SMALL CRAFT
CRITERIA AS WINDS TURN NORTHWEST.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...LOMBARDY
SHORT TERM...KEC
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
718 AM EDT TUE SEP 2 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE AREA TODAY EXTENDING FROM LOW
PRESSURE TRACKING NORTHEAST ACROSS QUEBEC. HIGH PRESSURE WILL
EXPAND OVER THE OHIO VALLEY TONIGHT...THEN TO THE EAST COAST ON
WEDNESDAY. A WARM FRONT WILL LIFT NORTH ON THURSDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM THAT WILL PASS NORTH OF THE GREAT LAKES
ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SWATH OF RAIN CAN BE SEEN ON UPSTREAM RADARS SPREADING NORTHEAST
ACROSS INDIANA EARLY THIS MORNING. THIS RAIN WILL CONTINUE TO BE
PULLED NORTHEAST AHEAD OF THE SHORTWAVE ENERGY MOVING ACROSS THE
PLAINS. THE 00Z SOUNDING OUT OF ILX SHOWED QUITE A BIT OF DRY AIR IN
THE COLUMN AHEAD OF THIS DEEPER PUSH OF MOISTURE AND THIS NOW
RESIDES OVER THE FORECAST AREA EARLY THIS MORNING. THE STRONGER
MOISTURE ADVECTION IS FOCUSED NEAR 700MB AND THE DRIER LOW LEVEL AIR
MAY CAUSE SOME EVAPORATION INITIALLY. THE BETTER INSTABILITY WILL BE
LOCATED FARTHER SOUTH AND TRENDS HAVE BEEN FOR THE DEEP CONVECTION
TO RESIDE ON THE SE FLANK OF THE PRECIPITATION SHIELD. WILL CARRY A
HIGH POP FOR JUST ABOUT ALL AREAS THIS MORNING...ALTHOUGH WILL ONLY
CARRY A CHANCE OF THUNDERSTORMS(BETTER CHANCES OF THUNDERSTORMS WILL
BE LOCATED ALONG AND SOUTH OF INTERSTATE 70 IN CENTRAL OHIO).
PRECIPITATION AMOUNTS WILL GENERALLY BE A HALF INCH OR LESS.
LOW PRESSURE IS LOCATED JUST EAST OF JAMES BAY THIS MORNING WITH THE
TRAILING COLD FRONT STILL LOCATED NORTH OF LAKE ERIE. THIS WEAK
FRONT IS EXPECTED TO MOVE THROUGH TOLEDO AROUND NOON...CLEVELAND
EARLY THIS AFTERNOON AND YOUNGSTOWN BY LATE AFTERNOON. ALTHOUGH THE
INITIAL SURGE OF MOISTURE WILL EXIT TO THE EAST...THE FRONT WILL
INTERACT WITH THE LINGERING MOISTURE WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EASTERN AREAS THIS AFTERNOON. THE STORM
PREDICTION CENTER HAS PLACED OUR SE TIER OF COUNTIES IN THE SLIGHT
RISK FOR SEVERE THUNDERSTORMS TODAY. EXPECTING A CONSIDERABLE AMOUNT
OF CLOUD COVER TO HAVE A LIMITING EFFECT ON HEATING/INSTABILITY
ALONG AND AHEAD OF THE FRONT THIS AFTERNOON. BETTER CHANCES OF
SEVERE WEATHER WILL BE LOCATED JUST SOUTH AND EAST OF THE AREA BUT
CAN NOT ENTIRELY RULE OUT A SEVERE STORM IF HEATING IS STRONGER THAN
EXPECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE WILL EXPAND EASTWARD ACROSS THE OHIO VALLEY TONIGHT.
IT LOOKS LIKE A WEAK THERMAL TROUGH WILL LINGER OVER LAKE ERIE ON
THE NORTH SIDE OF THE HIGH THIS EVENING AND MAY PROVIDE ENOUGH
CONVERGENCE FOR A FEW SHOWERS TO DEVELOP OVER THE LAKE. LEFT A LOW
POP BOTH OVER THE LAKE AND ALONG THE EASTERN LAKESHORE FOR A PORTION
OF THE NIGHT. INLAND AREAS...ESPECIALLY OUR SOUTHERN COUNTIES COULD
SEE SOME FOG OR STRATUS GIVEN THE LINGERING BOUNDARY LAYER MOISTURE
COUPLED WITH CLEARING SKIES AND LIGHT WINDS. TEMPERATURES WILL
BOTTOM OUT IN THE UPPER 50S TO LOW 60S.
THE AIRMASS DOES NOT COOL MUCH WITH THE FRONTAL PASSAGE AND
TEMPERATURES ARE STILL EXPECTED TO BE A COUPLE DEGREES ABOVE NORMAL
ON WEDNESDAY. THE MAIN DIFFERENCE WILL BE FELT IN THE HUMIDITY WHICH
WILL BE LOWER AND MORE PLEASANT WITH DEWPOINTS NEAR 60 DEGREES.
MAINLY JUST SCATTERED CU ON WEDNESDAY ONCE ANY MORNING CLOUDS BURN
OFF.
HEIGHTS WILL REBOUND OVER THE AREA ON THURSDAY AND A WARM FRONT WILL
LIFT NORTH AHEAD OF THE NEXT LOW PRESSURE SYSTEM TRACKING OUT OF THE
PLAINS. THIS SYSTEM IS FORECAST TO TRACK ACROSS LAKE SUPERIOR THEN
CONTINUE NORTHEAST ACROSS ONTARIO AND QUEBEC. ENOUGH DRY AIR SHOULD
STILL BE IN PLACE ON THURSDAY FOR THE FORECAST AREA TO STAY DRY.
LEFT THE 20 POP IN THE FORECAST ON THURSDAY NIGHT AS MOISTURE DOES
START TO INCREASE ALTHOUGH THE MORE FOCUSED MOISTURE ADVECTION WILL
BE WELL TO THE NORTH. THE ASSOCIATED COLD FRONT WILL SINK SOUTH
TOWARDS THE AREA ON FRIDAY. LOWERED POPS DURING THE MORNING HOURS
AND ACROSS THE SOUTHERN COUNTIES THAT SHOULD STRUGGLE TO SEE ANY
PRECIPITATION UNTIL FRIDAY NIGHT. TEMPERATURES ON THURSDAY AND
FRIDAY WILL BE IN THE MID 80S...WITH A FEW SPOTS MAKING A RUN AT THE
UPPER 80S.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NO BIG CHANGES TO THE MODELS FOR THE EXTENDED WITH GUIDANCE SHOWING
A COLD FRONT TO OUR SOUTH SATURDAY MORNING WITH DRIER AIR AND HIGH
MOVING IN FROM THE NORTH. DONT THINK THE DAY WILL BEGIN DRY HOWEVER
AS THE ECMWF REMAINS SLOWER THAN THE GFS IN MOVING MOISTURE OUT OF
THE AREA. WILL CONTINUE WITH CHANCE POPS THROUGH THE MORNING
SATURDAY BEFORE DROPPING TO A SLIGHT CHANCE ACROSS THE NORTH.
SATURDAY NIGHT THROUGH MONDAY LOOK DRY. TEMPS NEAR NORMAL AFTER AN
ABOVE NORMAL END TO THE WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
WEAK COLD FRONT TO OUR NORTHWEST NR A KFNT-KSBN LINE. FROM WILL
MOVE THROUGH THE AREA DURING THE DAY. CONVECTION FROM INDIANA
TRACKING ENE ACROSS CENTRAL AND SRN OHIO. WILL LIKELY SEE THUNDER
INTO NRN OHIO BUT KEPT MENTION OUT OF THE FAR NRN TAFS. HRRR MOVES
THIS PRECIP THROUGH DURING THE MORNING AND EARLY AFTERNOON WITH
POSSIBLY A FEW LINGERING SHOWERS FOR MID AFTERNOON. EXPECT MAINLY
MVFR CONDITIONS WITH AND JUST BEHIND THE PRECIP...LIFTING TO VFR 2
TO 4 HOURS AFTER PRECIP ENDS. EXPECT THE EVENING WILL BEGIN VFR
HOWEVER WITH LOW LEVEL MOISTURE IN PLACE...DRYING ALOFT AND HIGH
PRESSURE OVER THE AREA EXPECT MVFR AND POSSIBLY IFR CIGS/FOG TO
DEVELOP OVERNIGHT.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
WILL BEGIN TODAY CLOSE TO SMALL CRAFT CRITERIA MAINLY EAST OF
CONNEAUT BUT FOR NOW WILL CONTINUE WITH A FORECAST JUST BELOW. WINDS
TODAY WILL BE FROM THE SOUTHWEST AHEAD OF A WEAK COLD FRONT DUE IN
LATE MORNING/EARLY AFTERNOON. WINDS WILL TURN WEST TO BRIEFLY
NORTHWEST BEHIND THE BOUNDARY. HIGH PRESSURE BUILDS IN TONIGHT AND
WEDNESDAY. THURSDAY THE HIGH WILL DRIFT EAST AND A LOW WILL BE
MOVING THROUGH THE NORTHERN PLAINS. THIS WILL AGAIN SETUP SOUTHWEST
FLOW ON THE LAKE THURSDAY INCREASING TO 10 TO 20 KNOTS. THE LOW WILL
MOVE THROUGH EASTERN CANADA FRIDAY DRAGGING A COLD FRONT ACROSS THE
LAKE DURING THE AFTERNOON. WINDS WILL TURN NORTHWEST FRIDAY NIGHT
AND SATURDAY BEHIND THE FRONT. ALTHOUGH CLOSE...NO NEAR TERM
HEADLINES FOR NOW. FRIDAY INTO SATURDAY WE COULD REACH SMALL CRAFT
CRITERIA AS WINDS TURN NORTHWEST.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
711 AM EDT TUE SEP 2 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE AREA TODAY EXTENDING FROM LOW
PRESSURE TRACKING NORTHEAST ACROSS QUEBEC. HIGH PRESSURE WILL
EXPAND OVER THE OHIO VALLEY TONIGHT...THEN TO THE EAST COAST ON
WEDNESDAY. A WARM FRONT WILL LIFT NORTH ON THURSDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM THAT WILL PASS NORTH OF THE GREAT LAKES
ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LIGHT RAIN HAS SPREAD INTO THE TOLEDO AREA AND WILL CONTINUE TO
PUSH EASTWARD. POPS REMAIN PRETTY HIGH WITH THE MORNING UPDATE
ALTHOUGH SHOWERS WILL NOT LAST THAT LONG IN SOME AREAS. DRY AIR
CAN ALREADY BE SEEN OVER NRN INDIANA AND THE COVERAGE AND
INTENSITY OF SHOWERS HAS SHOWN A DECREASING TREND. STILL THINK
MOST AREAS WILL SEE RAIN SO POPS REMAIN HIGH AND CAN BE LOWERED
THROUGH THE DAY AS RAIN EXITS TO THE EAST.
PREVIOUS DISCUSSION...A SWATH OF RAIN CAN BE SEEN ON UPSTREAM
RADARS SPREADING NORTHEAST ACROSS INDIANA EARLY THIS MORNING. THIS
RAIN WILL CONTINUE TO BE PULLED NORTHEAST AHEAD OF THE SHORTWAVE
ENERGY MOVING ACROSS THE PLAINS. THE 00Z SOUNDING OUT OF ILX
SHOWED QUITE A BIT OF DRY AIR IN THE COLUMN AHEAD OF THIS DEEPER
PUSH OF MOISTURE AND THIS NOW RESIDES OVER THE FORECAST AREA EARLY
THIS MORNING. THE STRONGER MOISTURE ADVECTION IS FOCUSED NEAR
700MB AND THE DRIER LOW LEVEL AIR MAY CAUSE SOME EVAPORATION
INITIALLY. THE BETTER INSTABILITY WILL BE LOCATED FARTHER SOUTH
AND TRENDS HAVE BEEN FOR THE DEEP CONVECTION TO RESIDE ON THE SE
FLANK OF THE PRECIPITATION SHIELD. WILL CARRY A HIGH POP FOR JUST
ABOUT ALL AREAS THIS MORNING...ALTHOUGH WILL ONLY CARRY A CHANCE
OF THUNDERSTORMS(BETTER CHANCES OF THUNDERSTORMS WILL BE LOCATED
ALONG AND SOUTH OF INTERSTATE 70 IN CENTRAL OHIO). PRECIPITATION
AMOUNTS WILL GENERALLY BE A HALF INCH OR LESS.
LOW PRESSURE IS LOCATED JUST EAST OF JAMES BAY THIS MORNING WITH THE
TRAILING COLD FRONT STILL LOCATED NORTH OF LAKE ERIE. THIS WEAK
FRONT IS EXPECTED TO MOVE THROUGH TOLEDO AROUND NOON...CLEVELAND
EARLY THIS AFTERNOON AND YOUNGSTOWN BY LATE AFTERNOON. ALTHOUGH THE
INITIAL SURGE OF MOISTURE WILL EXIT TO THE EAST...THE FRONT WILL
INTERACT WITH THE LINGERING MOISTURE WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EASTERN AREAS THIS AFTERNOON. THE STORM
PREDICTION CENTER HAS PLACED OUR SE TIER OF COUNTIES IN THE SLIGHT
RISK FOR SEVERE THUNDERSTORMS TODAY. EXPECTING A CONSIDERABLE AMOUNT
OF CLOUD COVER TO HAVE A LIMITING EFFECT ON HEATING/INSTABILITY
ALONG AND AHEAD OF THE FRONT THIS AFTERNOON. BETTER CHANCES OF
SEVERE WEATHER WILL BE LOCATED JUST SOUTH AND EAST OF THE AREA BUT
CAN NOT ENTIRELY RULE OUT A SEVERE STORM IF HEATING IS STRONGER THAN
EXPECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE WILL EXPAND EASTWARD ACROSS THE OHIO VALLEY TONIGHT.
IT LOOKS LIKE A WEAK THERMAL TROUGH WILL LINGER OVER LAKE ERIE ON
THE NORTH SIDE OF THE HIGH THIS EVENING AND MAY PROVIDE ENOUGH
CONVERGENCE FOR A FEW SHOWERS TO DEVELOP OVER THE LAKE. LEFT A LOW
POP BOTH OVER THE LAKE AND ALONG THE EASTERN LAKESHORE FOR A PORTION
OF THE NIGHT. INLAND AREAS...ESPECIALLY OUR SOUTHERN COUNTIES COULD
SEE SOME FOG OR STRATUS GIVEN THE LINGERING BOUNDARY LAYER MOISTURE
COUPLED WITH CLEARING SKIES AND LIGHT WINDS. TEMPERATURES WILL
BOTTOM OUT IN THE UPPER 50S TO LOW 60S.
THE AIRMASS DOES NOT COOL MUCH WITH THE FRONTAL PASSAGE AND
TEMPERATURES ARE STILL EXPECTED TO BE A COUPLE DEGREES ABOVE NORMAL
ON WEDNESDAY. THE MAIN DIFFERENCE WILL BE FELT IN THE HUMIDITY WHICH
WILL BE LOWER AND MORE PLEASANT WITH DEWPOINTS NEAR 60 DEGREES.
MAINLY JUST SCATTERED CU ON WEDNESDAY ONCE ANY MORNING CLOUDS BURN
OFF.
HEIGHTS WILL REBOUND OVER THE AREA ON THURSDAY AND A WARM FRONT WILL
LIFT NORTH AHEAD OF THE NEXT LOW PRESSURE SYSTEM TRACKING OUT OF THE
PLAINS. THIS SYSTEM IS FORECAST TO TRACK ACROSS LAKE SUPERIOR THEN
CONTINUE NORTHEAST ACROSS ONTARIO AND QUEBEC. ENOUGH DRY AIR SHOULD
STILL BE IN PLACE ON THURSDAY FOR THE FORECAST AREA TO STAY DRY.
LEFT THE 20 POP IN THE FORECAST ON THURSDAY NIGHT AS MOISTURE DOES
START TO INCREASE ALTHOUGH THE MORE FOCUSED MOISTURE ADVECTION WILL
BE WELL TO THE NORTH. THE ASSOCIATED COLD FRONT WILL SINK SOUTH
TOWARDS THE AREA ON FRIDAY. LOWERED POPS DURING THE MORNING HOURS
AND ACROSS THE SOUTHERN COUNTIES THAT SHOULD STRUGGLE TO SEE ANY
PRECIPITATION UNTIL FRIDAY NIGHT. TEMPERATURES ON THURSDAY AND
FRIDAY WILL BE IN THE MID 80S...WITH A FEW SPOTS MAKING A RUN AT THE
UPPER 80S.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NO BIG CHANGES TO THE MODELS FOR THE EXTENDED WITH GUIDANCE SHOWING
A COLD FRONT TO OUR SOUTH SATURDAY MORNING WITH DRIER AIR AND HIGH
MOVING IN FROM THE NORTH. DONT THINK THE DAY WILL BEGIN DRY HOWEVER
AS THE ECMWF REMAINS SLOWER THAN THE GFS IN MOVING MOISTURE OUT OF
THE AREA. WILL CONTINUE WITH CHANCE POPS THROUGH THE MORNING
SATURDAY BEFORE DROPPING TO A SLIGHT CHANCE ACROSS THE NORTH.
SATURDAY NIGHT THROUGH MONDAY LOOK DRY. TEMPS NEAR NORMAL AFTER AN
ABOVE NORMAL END TO THE WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
WEAK COLD FRONT TO OUR NORTHWEST WITH BEST GUESS POSITION FROM
CENTRAL LWR MI SW INTO MO. MCS ACROSS MO AND SRN IL WHILE A FEW
LINGERING SHOWERS ALONG WITH A LITTLE THUNDER ACROSS FAR EASTERN
ERIE COUNTY PA AND EAST INTO WRN NY. THAT ACTIVITY WILL CONTINUE
EAST OUT OF THE AREA OVER THE NEXT HOUR OR TWO. HRRR DOES SHOW
SOME REDEVELOPMENT OVER ERIE COUNTY AND WILL ACCOUNT FOR THAT IN
THE TAF. OTHERWISE MAINLY VFR ACROSS THE AREA THIS HOURS ALTHOUGH
THE HRRR DOES SHOW ACTIVITY TO OUR WEST MOVING INTO THE AREA
TOWARDS MORNING. EXPECT THE BULK OF THE CONVECTION TO REMAIN SOUTH
OF OUR AREA...TRACKING ACROSS CENTRAL AND SRN OHIO...HOWEVER SO
EXPECT SOME PRECIP TO EXTEND NORTH AND AFFECT THE AREA. BROUGHT
SHOWERS INTO KTOL/KFDY AROUND 10Z AND KCLE/KMFD 11-12Z AND KERI-
KYNG 14-15Z. ALSO INCLUDED VCTS BUT FOR NOW DID NOT INCLUDE THUNDER IN
TEMPO GROUPS. HELD ONTO MVFR CIGS THROUGH THE BALANCE OF THE
MORNING GIVEN DEEP HIGH RH ACROSS THE AREA. DRIER AIR SHOULD BEGIN
MOVING IN THROUGH THE AFTERNOON.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
WILL BEGIN TODAY CLOSE TO SMALL CRAFT CRITERIA MAINLY EAST OF
CONNEAUT BUT FOR NOW WILL CONTINUE WITH A FORECAST JUST BELOW. WINDS
TODAY WILL BE FROM THE SOUTHWEST AHEAD OF A WEAK COLD FRONT DUE IN
LATE MORNING/EARLY AFTERNOON. WINDS WILL TURN WEST TO BRIEFLY
NORTHWEST BEHIND THE BOUNDARY. HIGH PRESSURE BUILDS IN TONIGHT AND
WEDNESDAY. THURSDAY THE HIGH WILL DRIFT EAST AND A LOW WILL BE
MOVING THROUGH THE NORTHERN PLAINS. THIS WILL AGAIN SETUP SOUTHWEST
FLOW ON THE LAKE THURSDAY INCREASING TO 10 TO 20 KNOTS. THE LOW WILL
MOVE THROUGH EASTERN CANADA FRIDAY DRAGGING A COLD FRONT ACROSS THE
LAKE DURING THE AFTERNOON. WINDS WILL TURN NORTHWEST FRIDAY NIGHT
AND SATURDAY BEHIND THE FRONT. ALTHOUGH CLOSE...NO NEAR TERM
HEADLINES FOR NOW. FRIDAY INTO SATURDAY WE COULD REACH SMALL CRAFT
CRITERIA AS WINDS TURN NORTHWEST.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
408 AM EDT TUE SEP 2 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE AREA TODAY EXTENDING FROM LOW
PRESSURE TRACKING NORTHEAST ACROSS QUEBEC. HIGH PRESSURE WILL
EXPAND OVER THE OHIO VALLEY TONIGHT...THEN TO THE EAST COAST ON
WEDNESDAY. A WARM FRONT WILL LIFT NORTH ON THURSDAY AHEAD OF THE
NEXT LOW PRESSURE SYSTEM THAT WILL PASS NORTH OF THE GREAT LAKES
ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SWATH OF RAIN CAN BE SEEN ON UPSTREAM RADARS SPREADING NORTHEAST
ACROSS INDIANA EARLY THIS MORNING. THIS RAIN WILL CONTINUE TO BE
PULLED NORTHEAST AHEAD OF THE SHORTWAVE ENERGY MOVING ACROSS THE
PLAINS. THE 00Z SOUNDING OUT OF ILX SHOWED QUITE A BIT OF DRY AIR IN
THE COLUMN AHEAD OF THIS DEEPER PUSH OF MOISTURE AND THIS NOW
RESIDES OVER THE FORECAST AREA EARLY THIS MORNING. THE STRONGER
MOISTURE ADVECTION IS FOCUSED NEAR 700MB AND THE DRIER LOW LEVEL AIR
MAY CAUSE SOME EVAPORATION INITIALLY. THE BETTER INSTABILITY WILL BE
LOCATED FARTHER SOUTH AND TRENDS HAVE BEEN FOR THE DEEP CONVECTION
TO RESIDE ON THE SE FLANK OF THE PRECIPITATION SHIELD. WILL CARRY A
HIGH POP FOR JUST ABOUT ALL AREAS THIS MORNING...ALTHOUGH WILL ONLY
CARRY A CHANCE OF THUNDERSTORMS(BETTER CHANCES OF THUNDERSTORMS WILL
BE LOCATED ALONG AND SOUTH OF INTERSTATE 70 IN CENTRAL OHIO).
PRECIPITATION AMOUNTS WILL GENERALLY BE A HALF INCH OR LESS.
LOW PRESSURE IS LOCATED JUST EAST OF JAMES BAY THIS MORNING WITH THE
TRAILING COLD FRONT STILL LOCATED NORTH OF LAKE ERIE. THIS WEAK
FRONT IS EXPECTED TO MOVE THROUGH TOLEDO AROUND NOON...CLEVELAND
EARLY THIS AFTERNOON AND YOUNGSTOWN BY LATE AFTERNOON. ALTHOUGH THE
INITIAL SURGE OF MOISTURE WILL EXIT TO THE EAST...THE FRONT WILL
INTERACT WITH THE LINGERING MOISTURE WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EASTERN AREAS THIS AFTERNOON. THE STORM
PREDICTION CENTER HAS PLACED OUR SE TIER OF COUNTIES IN THE SLIGHT
RISK FOR SEVERE THUNDERSTORMS TODAY. EXPECTING A CONSIDERABLE AMOUNT
OF CLOUD COVER TO HAVE A LIMITING EFFECT ON HEATING/INSTABILITY
ALONG AND AHEAD OF THE FRONT THIS AFTERNOON. BETTER CHANCES OF
SEVERE WEATHER WILL BE LOCATED JUST SOUTH AND EAST OF THE AREA BUT
CAN NOT ENTIRELY RULE OUT A SEVERE STORM IF HEATING IS STRONGER THAN
EXPECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
HIGH PRESSURE WILL EXPAND EASTWARD ACROSS THE OHIO VALLEY TONIGHT.
IT LOOKS LIKE A WEAK THERMAL TROUGH WILL LINGER OVER LAKE ERIE ON
THE NORTH SIDE OF THE HIGH THIS EVENING AND MAY PROVIDE ENOUGH
CONVERGENCE FOR A FEW SHOWERS TO DEVELOP OVER THE LAKE. LEFT A LOW
POP BOTH OVER THE LAKE AND ALONG THE EASTERN LAKESHORE FOR A PORTION
OF THE NIGHT. INLAND AREAS...ESPECIALLY OUR SOUTHERN COUNTIES COULD
SEE SOME FOG OR STRATUS GIVEN THE LINGERING BOUNDARY LAYER MOISTURE
COUPLED WITH CLEARING SKIES AND LIGHT WINDS. TEMPERATURES WILL
BOTTOM OUT IN THE UPPER 50S TO LOW 60S.
THE AIRMASS DOES NOT COOL MUCH WITH THE FRONTAL PASSAGE AND
TEMPERATURES ARE STILL EXPECTED TO BE A COUPLE DEGREES ABOVE NORMAL
ON WEDNESDAY. THE MAIN DIFFERENCE WILL BE FELT IN THE HUMIDITY WHICH
WILL BE LOWER AND MORE PLEASANT WITH DEWPOINTS NEAR 60 DEGREES.
MAINLY JUST SCATTERED CU ON WEDNESDAY ONCE ANY MORNING CLOUDS BURN
OFF.
HEIGHTS WILL REBOUND OVER THE AREA ON THURSDAY AND A WARM FRONT WILL
LIFT NORTH AHEAD OF THE NEXT LOW PRESSURE SYSTEM TRACKING OUT OF THE
PLAINS. THIS SYSTEM IS FORECAST TO TRACK ACROSS LAKE SUPERIOR THEN
CONTINUE NORTHEAST ACROSS ONTARIO AND QUEBEC. ENOUGH DRY AIR SHOULD
STILL BE IN PLACE ON THURSDAY FOR THE FORECAST AREA TO STAY DRY.
LEFT THE 20 POP IN THE FORECAST ON THURSDAY NIGHT AS MOISTURE DOES
START TO INCREASE ALTHOUGH THE MORE FOCUSED MOISTURE ADVECTION WILL
BE WELL TO THE NORTH. THE ASSOCIATED COLD FRONT WILL SINK SOUTH
TOWARDS THE AREA ON FRIDAY. LOWERED POPS DURING THE MORNING HOURS
AND ACROSS THE SOUTHERN COUNTIES THAT SHOULD STRUGGLE TO SEE ANY
PRECIPITATION UNTIL FRIDAY NIGHT. TEMPERATURES ON THURSDAY AND
FRIDAY WILL BE IN THE MID 80S...WITH A FEW SPOTS MAKING A RUN AT THE
UPPER 80S.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NO BIG CHANGES TO THE MODELS FOR THE EXTENDED WITH GUIDANCE SHOWING
A COLD FRONT TO OUR SOUTH SATURDAY MORNING WITH DRIER AIR AND HIGH
MOVING IN FROM THE NORTH. DONT THINK THE DAY WILL BEGIN DRY HOWEVER
AS THE ECMWF REMAINS SLOWER THAN THE GFS IN MOVING MOISTURE OUT OF
THE AREA. WILL CONTINUE WITH CHANCE POPS THROUGH THE MORNING
SATURDAY BEFORE DROPPING TO A SLIGHT CHANCE ACROSS THE NORTH.
SATURDAY NIGHT THROUGH MONDAY LOOK DRY. TEMPS NEAR NORMAL AFTER AN
ABOVE NORMAL END TO THE WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
WEAK COLD FRONT TO OUR NORTHWEST WITH BEST GUESS POSITION FROM
CENTRAL LWR MI SW INTO MO. MCS ACROSS MO AND SRN IL WHILE A FEW
LINGERING SHOWERS ALONG WITH A LITTLE THUNDER ACROSS FAR EASTERN
ERIE COUNTY PA AND EAST INTO WRN NY. THAT ACTIVITY WILL CONTINUE
EAST OUT OF THE AREA OVER THE NEXT HOUR OR TWO. HRRR DOES SHOW
SOME REDEVELOPMENT OVER ERIE COUNTY AND WILL ACCOUNT FOR THAT IN
THE TAF. OTHERWISE MAINLY VFR ACROSS THE AREA THIS HOURS ALTHOUGH
THE HRRR DOES SHOW ACTIVITY TO OUR WEST MOVING INTO THE AREA
TOWARDS MORNING. EXPECT THE BULK OF THE CONVECTION TO REMAIN SOUTH
OF OUR AREA...TRACKING ACROSS CENTRAL AND SRN OHIO...HOWEVER SO
EXPECT SOME PRECIP TO EXTEND NORTH AND AFFECT THE AREA. BROUGHT
SHOWERS INTO KTOL/KFDY AROUND 10Z AND KCLE/KMFD 11-12Z AND KERI-
KYNG 14-15Z. ALSO INCLUDED VCTS BUT FOR NOW DID NOT INCLUDE THUNDER IN
TEMPO GROUPS. HELD ONTO MVFR CIGS THROUGH THE BALANCE OF THE
MORNING GIVEN DEEP HIGH RH ACROSS THE AREA. DRIER AIR SHOULD BEGIN
MOVING IN THROUGH THE AFTERNOON.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
WILL BEGIN TODAY CLOSE TO SMALL CRAFT CRITERIA MAINLY EAST OF
CONNEAUT BUT FOR NOW WILL CONTINUE WITH A FORECAST JUST BELOW. WINDS
TODAY WILL BE FROM THE SOUTHWEST AHEAD OF A WEAK COLD FRONT DUE IN
LATE MORNING/EARLY AFTERNOON. WINDS WILL TURN WEST TO BRIEFLY
NORTHWEST BEHIND THE BOUNDARY. HIGH PRESSURE BUILDS IN TONIGHT AND
WEDNESDAY. THURSDAY THE HIGH WILL DRIFT EAST AND A LOW WILL BE
MOVING THROUGH THE NORTHERN PLAINS. THIS WILL AGAIN SETUP SOUTHWEST
FLOW ON THE LAKE THURSDAY INCREASING TO 10 TO 20 KNOTS. THE LOW WILL
MOVE THROUGH EASTERN CANADA FRIDAY DRAGGING A COLD FRONT ACROSS THE
LAKE DURING THE AFTERNOON. WINDS WILL TURN NORTHWEST FRIDAY NIGHT
AND SATURDAY BEHIND THE FRONT. ALTHOUGH CLOSE...NO NEAR TERM
HEADLINES FOR NOW. FRIDAY INTO SATURDAY WE COULD REACH SMALL CRAFT
CRITERIA AS WINDS TURN NORTHWEST.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
152 AM EDT TUE SEP 2 2014
.SYNOPSIS...
A COLD FRONT WILL REACH THE NORTHERN OHIO VALLEY BY DAYBREAK AND
CROSS THE REGION FROM THE NORTHWEST ON TUESDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN BEHIND THE FRONT...WITH DRY CONDITIONS EXPECTED
FOR WEDNESDAY. A RETURN TO SOUTHERLY FLOW WILL INCREASE THE THREAT
FOR SHOWERS AND STORMS AT THE END OF THE WEEK...CULMINATING ON
SATURDAY AS THE NEXT COLD FRONT CROSSES THE REGION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ONLY A FEW SHOWERS LINGERING IN THE FAR EASTERN ZONES AND THEY
WILL MOVE OUT BEFORE MIDNIGHT. SHOWERS AND STORMS OCCURRING IN THE
CENTRAL PLAINS WILL SPREAD EAST NORTHEAST TOWARDS THE REGION. HRRR
AND RAP MODELS SHOWING SOME TIMING DISCREPANCIES. BUT IT APPEARS
THAT ACTIVITY WILL NOT SPREAD INTO WESTERN ZONES UNTIL VERY LATE
TONIGHT. EXPECT ANY HEAVIER RAINFALL TO CLOSER TO THE END OF THE
PERIOD AND INTO TUESDAY. FORECAST LOWS LOOK REASONABLE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
BY THE TIME DAYLIGHT HOURS OF TUESDAY ROLLS AROUND...THE SYSTEM IS
EXPECTED TO SHIFT THE SW-NE AXIS MORE INTO THE CWA AND ALONG THE
I-71 CORRIDOR. AREAS THAT SAW EXCESSIVE RAINFALL ON SATURDAY MAY
BE HIT WITH ANOTHER SOAKER...BUT THE UNUSUALLY HIGH VALUES SHOULD
NOT MAKE ANOTHER APPEARANCE...AT LEAST OVER WARREN AND GREENE
COUNTIES. PRECIP DURING THE DAY OVER THE CWA WILL BE PROGRESSIVE
AND EXPAND SOUTHEAST TO COVER THE REST OF CWA BY THE AFTERNOON.
HIGH TEMPS WILL BE MUTED DUE TO THE RAINFALL...GENERALLY IN THE
LOW 80S...SOME MID 80S ARE POSSIBLE IF THE RAIN HOLDS OFF A FEW
HOURS OVER THE SOUTHEAST.
HIGH PRESSURE WILL BRIEFLY FILL IN BEHIND THE COLD FRONT AND
PROVIDE ENOUGH DOWNWARD MOTION TO HELP SCOUR OUT MOST OF THE CLOUD
COVER AND USHER IN SOME DRIER AIR. THE DRIEST AIR AND SUBSEQUENT
COOLER TEMPERATURES FOR TUESDAY NIGHT WILL BE FOUND ALONG AND
NORTH OF THE I-70 CORRIDOR...WITH THE AREA EAST OF COLUMBUS
GETTING THE BEST COOLING BOTH TUES AND WED NIGHTS. NORTH OF DAYTON
ON WED NIGHT WILL LIKELY BE INVOLVED WITH THE RETURNING WARMER AND
MORE MOIST AIR ON THE SOUTHERLY WINDS.
HIGHS ON WEDNESDAY WILL REACH THE LOW TO MID 80S ACROSS THE
REGION.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
PERIOD BEGINS WITH A WEAK WARM FRONT LIFTING UP THROUGH THE WRN OHIO
VALLEY. AS FRONT LIFTS UP ACROSS THE AREA THURSDAY...THERE WILL BE A
SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM.
BY FRIDAY...A CDFNT BEGINS TO PUSH THROUGH THE GREAT LAKES. MODELS
ARE SHOWING A RANGE ON THE FROPA TIMING. THE GFS IS THE
QUICKEST...WHILE THE ECMWF IS ON THE SLOWER END OF THE GUIDANCE.
BOTH MODELS SHOW FROPA FRIDAY NIGHT INTO SATURDAY MORNING WITH
CONTINUED PCPN CHANCES ON SATURDAY. PUT THE BEST POPS FRIDAY NIGHT
WITH 50 POP ACROSS THE REGION. REDEVELOPED THE PCPN SATURDAY MORNING
WITH 50 POPS ACROSS THE SOUTH...BUT LOWER POPS TO THE NW.
THE GFS DRIES THINGS OUT QUICKER SATURDAY NIGHT AS COMPARED TO THE
ECMWF WHICH LEAVES LINGERING PCPN CHANCES INTO SATURDAY NIGHT ACROSS
THE SOUTH. HELD ON TO 20 POPS FOR THE EVENING HOURS IN THE SOUTHEAST.
HIGH PRESSURE BUILDS ACROSS THE REGION SUNDAY INTO MONDAY.
WARM AND HUMID CONDITIONS ARE EXPECTED FOR THURSDAY AND FRIDAY.
HIGHS WILL BE IN THE UPPER 80S TO 90 WITH DEWPOINTS IN THE UPPER 60S
TO LOWER 70S. COOLER CONDITIONS SATURDAY WITH HIGHS RANGING FROM THE
MID 70S IN THE NORTH TO THE LOWER 80S IN NRN KY. BY SUNDAY AND
MONDAY...HIGHS WILL BE IN THE LOWER TO MID 70S ACROSS THE REGION.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SOME SPOTTY MVFR STRATUS IS STARTING TO DEVELOP ACROSS THE AREA AND
THIS COULD FILL IN A BIT MORE OVER THE NEXT HOUR OR SO. HOWEVER...THINK
THE QUICKLY THICKENING CIRRUS SHIELD SHOULD PREVENT IT FROM
BECOMING TOO WIDESPREAD. OTHERWISE...AN AREA OF SHOWERS AND
THUNDERSTORMS PROGRESSING EAST ACROSS EASTERN ILLINOIS AND WESTERN
INDIANA SHOULD APPROACH THE WESTERN TAF SITES TOWARD 09Z AND THE
EASTERN TAF SITES AROUND 11Z. PCPN IS ASSOCIATED WITH A GOOD LOW
LEVEL JET THAT IS FORECAST TO SHIFT EAST INTO OUR AREA THROUGH 12Z
BEFORE BEGINNING TO WEAKEN BETWEEN 12Z AND 15Z. THIS SHOULD ALLOW
FOR AN OVERALL WEAKENING TREND IN THE THUNDERSTORM INTENSITY/COVERAGE
THROUGH MID TO LATE MORNING AS IT PROGRESSES EAST ACROSS OUR AREA.
AS THIS INITIAL WAVE PUSHES EAST OF THE AREA...WE COULD SEE A LULL
IN THE PCPN FROM LATE MORNING INTO EARLY AFTERNOON. HOWEVER...AS
WE DESTABILIZE THROUGH THE AFTERNOON...EXPECT TO SEE SOME ISOLATED
TO SCATTERED THUNDERSTORM REDEVELOPMENT. DRIER AIR WILL PUSH IN
FROM THE NORTHWEST LATE THIS AFTERNOON INTO THIS EVENING...ALLOWING
FOR DECREASING CLOUDS THROUGH THE END OF THE TAF PERIOD.
OUTLOOK...MVFR TO IFR VISIBILITIES ARE POSSIBLE LATE TUESDAY NIGHT
INTO WEDNESDAY MORNING. THUNDERSTORMS POSSIBLE FRIDAY INTO
SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
122 AM EDT TUE SEP 2 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA ON TUESDAY. HIGH
PRESSURE WILL BUILD NORTH OUT OF THE GULF COAST STATES TUESDAY
THROUGH THURSDAY AND THEN MOVE TO THE EAST COAST. A WARM FRONT WILL
LIFT NORTH ACROSS THE REGION THURSDAY AS LOW PRESSURE MOVES EAST
ACROSS THE NORTHERN LAKES THURSDAY NIGHT. A COLD FRONT TRAILING FROM
THE LOW WILL SAG SOUTHEAST OVER THE REGION FRIDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE PREFRONTAL TROUGH
ARE LOCATED OUT OVER LAKE ERIE AND ARE MOVING WITH AN EAST-
NORTHEAST DIRECTION. THEREFORE THEY MAY CLIP ERIE COUNTY PA BEFORE
HEADING OFF TO NY. ALL OTHERS WILL BE PRIMARILY DRY ALTHOUGH
CANNOT RULE OUT A STRAY SHOWER/TS OVERNIGHT.
A COLD FRONT WAS LOCATED FAR TO THE WEST...NEAR CHICAGO. THE
BETTER CHANCE OF PRECIPITATION COMES MUCH LATER TONIGHT AS A WAVE
DEVELOPS ALONG THIS FRONT WITH SUPPORT OF AN UPPER LEVEL WAVE AND
JET MAX. A STEADIER RAIN WITH EMBEDDED THUNDER WILL BEGIN TO WORK
ITS WAY IN FROM THE FINDLAY AREA NORTHEAST TOWARD MORNING. THERE
IS SOME QUESTION AS TO HOW FAST IT CAN MOVE INTO THE AREA BEFORE 6
AM.
AREA WILL STILL BE IN THE WARM SECTOR OVERNIGHT AND EXPECT LOWS
ONLY IN THE UPPER 60S AND LOWER 70S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
MORNING SHORTWAVE WILL PULL NORTHEAST AND DIMINISH THE RAIN
CHANCES AS THE DAY GOES ON TUESDAY. THE BIGGEST QUESTION IS HOW
FAR NORTH THIS AREA OF RAIN TRACKS. HAVE TOLEDO IN THE CHANCE
CATEGORY...AND THE SOUTHEAST THIRD OF THE AREA IN CATEGORICAL
POPS. THE COLD FRONT WILL CROSS THE AREA DURING THE DAY ON
TUESDAY...WITH IMPROVEMENT FROM WEST TO EAST.
THE BROAD UPPER LEVEL TROUGH WILL BEGIN TO LIFT OUT OF THE AREA ON
TUESDAY ALLOWING FOR ZONAL FLOW TO DEVELOP FROM WEST TO EAST
THROUGH THIS PERIOD.
HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE GULF COAST STATES AND
BRING DRIER AIR TO THE REGION. THE HIGH PRESSURE WILL BECOME THE
DOMINATING WEATHER FEATURE THROUGH WEDNESDAY. A WARM FRONT WILL LIFT
NORTHEAST ALONG WITH SOME LIMITED MEAN 1000 TO 500 MB MOISTURE ON
THURSDAY AND WE COULD SEE A MINIMAL CHANCE FOR SHOWERS AND
THUNDERSTORMS BY THURSDAY NIGHT. WILL HOLD ON TO THE SLIGHT CHANCE
AT THIS POINT SINCE MOISTURE WILL BE SO LIMITED.
AIR MASS BEHIND THE COLD FRONT IS NOT THAT STRONG SO NOT EXPECTING
TOO MUCH IN THE WAY OF COLD AIR ADVECTION ON TUESDAY INTO TUESDAY
NIGHT. LOWS WILL DROP OFF HOWEVER ABOUT 10 DEGREES TUESDAY NIGHT AND
THEN BEGIN TO RECOVER WEDNESDAY AND WEDNESDAY NIGHT AS WARM AIR
ADVECTION BEGINS TO TAKE PLACE. FURTHER WARMING TAKES PLACE THURSDAY
AND THURSDAY NIGHT IN THE EARNEST WARM AIR ADVECTION. 850 MB
TEMPERATURES CLIMB FROM 16C ON TUESDAY BACK TO AROUND 20C BY
THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MODELS IN FAIR AGREEMENT TODAY. WILL START TO SEE PRECIP CHANCES
INCREASE ON FRIDAY AS A MOIST SOUTHERLY FLOW DEVELOPS AHEAD OF A
COLD FRONT. FRIDAY NIGHT AND SATURDAY WILL BE WET AND THE LIKELY
POPS IN THE PREVIOUS FORECAST SEEM REASONABLE. THE COLD FRONT WILL
MOVE SOUTH ACROSS THE AREA SATURDAY AND PRECIP SHOULD END DURING THE
AFTERNOON. THERE WILL BE A DISTINCT AIR MASS CHANGE BEHIND THIS
FRONT WITH DEW POINTS DIPPING INTO THE 40S AND TEMPERATURES BECOMING
BELOW NORMAL. BY MONDAY...MORNING LOWS WILL BE IN THE 40S SOME AREAS
WITH HIGHS STRUGGLING TO GET TO 70. WITH HIGH PRESSURE OVERHEAD
THERE SHOULD BE A LOT OF SUNSHINE BOTH SUNDAY AND MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
WEAK COLD FRONT TO OUR NORTHWEST WITH BEST GUESS POSITION FROM
CENTRAL LWR MI SW INTO MO. MCS ACROSS MO AND SRN IL WHILE A FEW
LINGERING SHOWERS ALONG WITH A LITTLE THUNDER ACROSS FAR EASTERN
ERIE COUNTY PA AND EAST INTO WRN NY. THAT ACTIVITY WILL CONTINUE
EAST OUT OF THE AREA OVER THE NEXT HOUR OR TWO. HRRR DOES SHOW
SOME REDEVELOPMENT OVER ERIE COUNTY AND WILL ACCOUNT FOR THAT IN
THE TAF. OTHERWISE MAINLY VFR ACROSS THE AREA THIS HOURS ALTHOUGH
THE HRRR DOES SHOW ACTIVITY TO OUR WEST MOVING INTO THE AREA
TOWARDS MORNING. EXPECT THE BULK OF THE CONVECTION TO REMAIN SOUTH
OF OUR AREA...TRACKING ACROSS CENTRAL AND SRN OHIO...HOWEVER SO
EXPECT SOME PRECIP TO EXTEND NORTH AND AFFECT THE AREA. BROUGHT
SHOWERS INTO KTOL/KFDY AROUND 10Z AND KCLE/KMFD 11-12Z AND KERI-
KYNG 14-15Z. ALSO INCLUDED VCTS BUT FOR NOW DID NOT INCLUDE THUNDER IN
TEMPO GROUPS. HELD ONTO MVFR CIGS THROUGH THE BALANCE OF THE
MORNING GIVEN DEEP HIGH RH ACROSS THE AREA. DRIER AIR SHOULD BEGIN
MOVING IN THROUGH THE AFTERNOON.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
SOUTHWEST TO SOUTH FLOW WILL CONTINUE TILL A COLD FRONT CROSSES THE
LAKE ON TUESDAY. IT APPEARS SHOWERS AND THUNDERSTORMS WILL OCCUR ON
THE LAKE THIS EVENING AND AGAIN RIGHT AHEAD OF THE COLD FRONT EARLY
THURSDAY. SOME OF THE STORMS ON THE WEST END COULD BE STRONG THIS
EVENING. LOOKS LIKE SPEEDS AND WAVES WILL REMAIN JUST BELOW SMALL
CRAFT CRITERIA TONIGHT SO WILL HOLD OFF ON ANY ISSUANCE. THE FLOW
WILL BECOME WESTERLY BEHIND THE FRONT. HIGH PRESSURE WILL BUILD
OVER THE LAKE FOR THE MIDDLE PART OF THE WEEK RESULTING IN LIGHT AND
VARIABLE FLOW. THE SURFACE RIDGE WILL EVENTUALLY MOVE OFF TO THE
EAST ON THURSDAY ALLOWING A WEAK SOUTHERLY FLOW TO DEVELOP. S TO SW
FLOW WILL THEN GRADUALLY INCREASE TILL A COLD FRONT CROSSES THE LAKE
ON SATURDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY/OUDEMAN
SHORT TERM...LOMBARDY/OUDEMAN
LONG TERM...KUBINA
AVIATION...TK
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS TULSA OK
844 PM CDT WED SEP 3 2014
.DISCUSSION...
HEAT INDICES HAVE IMPROVED AND THE WINDS HAVE BACKED OFF AS MIXING
CEASES WITH THE SETTING OF THE GIANT ENERGY BALL. A LEE TROUGH
OVER THE HIGH PLAINS WILL KEEP SOME SOUTH WIND GOING ALL
NIGHT...ESPECIALLY AT TUL...SO LOWS WILL BE MILD ACROSS ERN OK AND
W CNTRL AR WHERE TERRAIN EFFECTS HELP TO MAINTAIN AN EAST WIND.
RIDGING ALOFT WILL MAINTAIN DRY CONDITIONS UNTIL A FRONT ARRIVES
LATE FRIDAY.
LACY
&&
.PREV DISCUSSION... /ISSUED 604 PM CDT WED SEP 3 2014/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD
AT ALL SITES.
PREV DISCUSSION... /ISSUED 353 PM CDT WED SEP 3 2014/
DISCUSSION...
WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH
PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME
SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE
THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP
AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS
EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA
FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE
CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING
CONDITIONS.
HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL
CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED
TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE
U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD
THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS
THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY
AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS
AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH
SOUTHWESTERLY WINDS.
THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY
NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND
THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY
NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH
THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE
OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE
EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK.
SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR
THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST
TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND
ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD
FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED
TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS
FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE
MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE
FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 97 75 94 / 0 0 10 30
FSM 74 95 73 95 / 0 10 10 10
MLC 75 95 74 94 / 0 0 0 10
BVO 73 96 69 92 / 0 10 10 40
FYV 69 91 67 92 / 10 10 10 30
BYV 70 93 69 92 / 10 10 10 30
MKO 74 95 73 94 / 0 10 10 30
MIO 73 95 71 91 / 0 10 10 40
F10 75 95 74 94 / 0 0 10 30
HHW 74 95 73 95 / 0 0 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
531 PM CDT TUE SEP 2 2014
.UPDATE...
THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND CENTRAL SOUTH
PLAINS...A BIT SOUTH OF PREVIOUS BEST-GUESS...BUT GIVE SHORT TERM
SOLUTIONS SOME CREDIT. WE HAVE UPDATED FOR LOW COVERAGE THUNDER
THROUGH EARLY THIS EVENING. 1500-2000 JOULES PER KILOGRAM OF
CONVECTIVE ENERGY BUT VERY LITTLE SHEAR CONTRIBUTING TO BRIEF
HEAVY SHOWERS AND BRIEF MOSTLY WEAK HAIL INDICATIONS AT THIS TIME.
ACTIVITY SHOULD TAKE ON BETTER NORTHERLY DRIFT...THOUGH BELIEVE
MOST ACTIVITY WILL RELENT BY DARK. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 2 2014/
SHORT TERM...
FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS
AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET
ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE
EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS
SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY
MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS
AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK
FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE
WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5
DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS
HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM
HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE
FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING
OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT
WARRANTING MENTION IN THE ZONE FCST ATTM.
WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH
STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING
MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH
BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY
ATTM.
LONG TERM...
ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS
A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND
FOR PARTS OF THE REGION.
BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN
PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE
ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS. WHILE THIS WILL
CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK
WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW
TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER
80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS.
BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH
WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A
MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST
THE TEXAS PANHANDLE. MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY
WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE
DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT
GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE
PREVIOUSLY MENTIONED TROUGH. ALL OF THIS IS EXPECTED TO RESULT IN
INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND
POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS.
THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND
STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN
ABOUT 24 HOURS APART IN THIS REGARD. THE GFS INDICATES A
SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE
SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY.
MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS
EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA
BY LATE SATURDAY. THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE
HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY
TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY
THROUGH LATE SUNDAY TIME FRAME. GIVEN THAT THE BOUNDARY WILL BE WELL
REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS
LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND
HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS. LIKEWISE...LOW END POPS
WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER
SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY
LINGER THROUGH THIS PERIOD. HOWEVER...UNCERTAINTIES REGARDING
FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH
THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING
OUTFLOWS.
BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS
THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY. THIS
SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN
ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 92 62 90 62 / 10 0 10 10 10
TULIA 68 93 66 91 66 / 20 0 10 0 10
PLAINVIEW 68 93 66 90 66 / 20 0 0 0 10
LEVELLAND 66 92 66 90 67 / 20 0 10 10 0
LUBBOCK 72 93 68 92 67 / 20 0 0 10 0
DENVER CITY 66 91 66 89 66 / 20 0 10 10 10
BROWNFIELD 68 93 67 90 67 / 20 0 0 10 0
CHILDRESS 75 97 75 96 72 / 10 0 0 0 0
SPUR 73 97 72 94 71 / 10 0 0 10 10
ASPERMONT 76 99 74 96 73 / 0 0 0 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/99
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
306 PM CDT TUE SEP 2 2014
.SHORT TERM...
FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS
AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET
ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE
EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS
SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY
MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS
AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK
FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE
WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5
DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS
HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM
HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE
FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING
OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT
WARRANTING MENTION IN THE ZONE FCST ATTM.
WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH
STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING
MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH
BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY
ATTM.
&&
.LONG TERM...
ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS
A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND
FOR PARTS OF THE REGION.
BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN
PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE
ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS. WHILE THIS WILL
CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK
WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW
TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER
80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS.
BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH
WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A
MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST
THE TEXAS PANHANDLE. MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY
WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE
DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT
GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE
PREVIOUSLY MENTIONED TROUGH. ALL OF THIS IS EXPECTED TO RESULT IN
INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND
POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS.
THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND
STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN
ABOUT 24 HOURS APART IN THIS REGARD. THE GFS INDICATES A
SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE
SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY.
MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS
EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA
BY LATE SATURDAY. THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE
HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY
TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY
THROUGH LATE SUNDAY TIME FRAME. GIVEN THAT THE BOUNDARY WILL BE WELL
REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS
LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND
HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS. LIKEWISE...LOW END POPS
WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER
SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY
LINGER THROUGH THIS PERIOD. HOWEVER...UNCERTAINTIES REGARDING
FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH
THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING
OUTFLOWS.
BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS
THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY. THIS
SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN
ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 92 62 90 62 / 10 0 10 10 10
TULIA 68 93 66 91 66 / 10 0 10 0 10
PLAINVIEW 68 93 66 90 66 / 10 0 0 0 10
LEVELLAND 66 92 66 90 67 / 0 0 10 10 0
LUBBOCK 71 93 68 92 67 / 10 0 0 0 0
DENVER CITY 66 91 66 89 66 / 0 0 10 10 10
BROWNFIELD 68 93 67 90 67 / 0 0 0 10 0
CHILDRESS 75 97 75 96 72 / 10 0 0 0 0
SPUR 73 97 72 94 71 / 10 0 0 10 10
ASPERMONT 76 99 74 96 73 / 0 0 0 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/16
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1257 PM CDT TUE SEP 2 2014
.DISCUSSION...
18Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
LITTLE REGIONAL AIR MASS CHANGE OVER THE NEXT 24-30 HOURS. THE
RESIDENT UNSTABLE AIR MASS WILL REMAIN UNSEASONABLY MOIST THROUGH
THURSDAY. ALTHOUGH MOST CONVECTIVE ACTIVITY WILL REMAIN NORTH OF
THE METRO HUBS TODAY...INCREASING CHANCES FOR MORE WIDESPREAD GULF
PRECIPITATION MOVING INLAND DURING THE EARLY AM WED HOURS WILL
PLACE MORE COASTAL TERMINALS UNDER MODERATE CHANCES FOR SPEED
CONVERGENCE SHRA OR TSRA THROUGH SUNRISE. THUS...THE THINKING IS
THAT MANY TERMINALS WILL EXPERIENCE BRIEF PERIODS OF PASSING
SHOWERS...WITH THAT EVEN SHORTER-LIVED THUNDERSTORM...PASSING
WITHIN THE VICINITY FROM LATE MORNING THROUGH MID-AFTERNOON. 31
&&
.PREV DISCUSSION... /ISSUED 1026 AM CDT TUE SEP 2 2014/
UPDATE...
SEE MORNING UPDATE.
DISCUSSION...
12Z SOUNDINGS SHOW PW VALUES BETWEEN 2.1 AND 2.2 INCHES AND THIS
IS SUPPORTED BY GPS MET DATA, CONVECTIVE TEMPS ARE BETWEEN 86 AND
88 DEGREES TODAY AND THIS THRESHOLD WILL BE MET EASILY. A WELL
DEVELOPED S/WV EXTENDS FROM CENTRAL ARKANSAS INTO CENTRAL TEXAS
WHICH SERVE AS ANOTHER FOCUS FOR SHRA/TSRA. UPPER LEVEL RIDING HAS
INCHED CLOSER TO SE TX WHICH WILL IMPART A BIT OF SUBSIDENCE. THE
RAP IS VERY AGGRESSIVE WITH RAINFALL THIS AFTN WHILE THE
HRRR/ARW-EAST REMAIN MORE BENIGN. THE RAP WAS OVERDONE YESTERDAY
AND DID NOT INITIALIZE ALL THAT WELL SO HAVE LEANED TOWARD A HRRR/WRF
BLEND. CHANCE POPS LOOK APPROPRIATE SO NO CHANGES TO THE POP/WX
GRIDS. DID BUMP MAX T GRIDS UP A FEW DEGREES TO MATCH TRENDS/OBS.
AS FOR TS DOLLY...THE STORM WILL PROBABLY MAKE LANDFALL A BIT
EARLIER...SOMETIME THIS EVENING. THE MAIN EFFECT FOR SE TX WILL BE
INCREASING SWELLS OVER THE OFFSHORE MARINE ZONES AND A 1.0-1.5
FOOT BUMP UP IN TIDE LEVELS. NEW ZONES OUT BY 1030 AM. 43
&&
PREV DISCUSSION... /ISSUED 405 AM CDT TUE SEP 2 2014/
DISCUSSION...
A FEW SHOWERS ARE MOVING NORTHWARD ACROSS THE COASTAL WATERS THIS
MORNING IN ASSOCIATION WITH AN AREA OF DEEPER MOISTURE WHICH IS
APPROACHING THE UPPER TEXAS COAST. FURTHER TO THE SOUTH...TD 5 HAS
STRENGTHENED INTO TROPICAL STORM DOLLY THIS MORNING. THE CENTER OF
THE SYSTEM HAS FORMED A BIT FURTHER NORTH THAT PREVIOUSLY EXPECTED
WHICH HAS CAUSED A CORRESPONDING SHIFT IN THE FORECAST TRACK. THE
ONLY ADDITIONAL IMPACTS TO SOUTHEAST TEXAS WILL BE SOME SLIGHTLY
HIGHER SEAS OFFSHORE AS THE NEW TRACK STILL TAKES THE SYSTEM INTO
MEXICO WELL SOUTH OF THE BORDER.
EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP INLAND LATER
THIS MORNING AS MOISTURE STREAMS BACK INTO THE REGION. COVERAGE
SHOULD INCREASE ACROSS OUR NORTHERN COUNTIES LATE THIS AFTERNOON
AS A PASSING SHORTWAVE BRINGS ADDITIONAL LIFT TO THE REGION. GIVEN
THE RICH MOISTURE A FEW BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE
WITH THE ACTIVITY TODAY. HIGH TEMPERATURES SHOULD REMAIN IN THE
LOW TO MID 90S AREAWIDE WITH THE PRECIPITATION AND GREATER CLOUD
COVER.
ONLY SLIGHT CHANGES FOR THE MID TO EXTENDED RANGE FORECAST THIS
MORNING. THE UPPER LEVEL PATTERN OVERHEAD REMAINS RELATIVELY
UNCHANGED THROUGH THE WEEK WITH A BROAD FLAT RIDGE ACROSS THE
SOUTHERN UNITED STATES. THIS WILL ALLOW FOR CONTINUED DIURNALLY
DRIVEN SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES IN THE LOW
TO MID 90S...NEAR THE NORMALS FOR THE FIRST WEEK OF SEPTEMBER. 38
&&
MARINE...
TROPICAL STORM DOLLY IS LOCATED IN THE BAY OF CAMPECHE EARLY
THIS MORNING. BASED ON THE CURRENT FORECAST...DOLLY IS EXPECTED
TO APPROACH THE COAST OF MEXICO BY TONIGHT AND MOVE INLAND BY
WEDNESDAY MORNING. BUILDING SEAS CAN BE EXPECTED ALONG THE UPPER
TEXAS COAST. CAUTION FLAGS ARE CURRENTLY IN EFFECT...AND ADVISORIES
MIGHT BE NEEDED IF SEAS BUILD HIGHER THAN ANTICIPATED. PERIODS OF
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED ACROSS OUR AREA OVER THE
NEXT COUPLE OF DAYS. TOWARD THE END OF THE WEEK...EXPECT WEAKENING
ONSHORE WINDS AND LOWERING SEAS. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 95 75 94 75 / 20 20 10 20 10
HOUSTON (IAH) 77 93 76 92 76 / 20 30 10 20 10
GALVESTON (GLS) 81 91 81 90 81 / 20 30 20 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 8 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AVIATION/MARINE...31
CONTINUE ON WITH THE FORECAST DISCUSSION...
IN A BASIC SENSE...THE MOVEMENT OF THUNDERSTORM SYSTEMS IS
CONTROLLED BY THE AVERAGE OF THE WINDS ALOFT...OFTEN REFERRED TO
AS THE STEERING WINDS. IN MOST CASES...THUNDERSTORMS WILL SIMPLY
MOVE IN THE DIRECTION IN WHICH THE WINDS ALOFT ARE BLOWING.
HOWEVER THE SECOND COMPONENT TO CONSIDER IS OFTEN REFERRED TO AS
THE PROPAGATION COMPONENT OF STORM MOTION. PROPAGATION INFLUENCES
STORM MOTION BY CHANGING THE DIRECTION OF MOTION OF A THUNDERSTORM
SYSTEM IN THE DIRECTION THAT NEW THUNDERSTORMS DEVELOP. THIS IS
THE MORE COMPLICATED FACTOR TO UNDERSTAND...BUT IN GENERAL...NEW
THUNDERSTORMS TEND TO DEVELOP IN THE OPPOSITE DIRECTION OF THE LOW
LEVEL JET. ON A DAY LIKE TODAY...WHERE THE STEERING WINDS ARE
SOMEWHAT LIGHT DUE TO UPPER LEVEL RIDGING OVER TEXAS...BUT THE
LOW-LEVEL JET IS RELATIVELY STRONG...THE PROPAGATION COMPONENT CAN
DOMINATE THE DIRECTION IN WHICH THE THUNDERSTORM SYSTEM MOVES. FOR
TODAY...THE STEERING WINDS ARE SOMEWHAT LIGHT AND WOULD INDICATE
AN EASTERLY STORM MOTION. THIS IS WHY THE STORMS ARE JUST SORT OF
SITTING THERE ALONG THE FRONT AS OF 3 AM. HOWEVER IF THIS RESULTS
IN A STRONG ENOUGH COLD POOL (A COLLECTION OF RAIN COOLED AIR)
THIS COLD POOL COULD START TO SURGE SOUTH...CAUSING NEW STORMS TO
DEVELOP IN THE OPPOSITE DIRECTION OF THE LOW-LEVEL JET. SINCE THE
LOW-LEVEL JET EXTENDS FROM OUR CWA TO THE FRONT...THE WHOLE
COMPLEX OF STORMS COULD START TO MOVE SOUTH DIRECTLY TOWARDS THE
RED RIVER...BUT WILL STILL MOVE AT LEAST SLIGHTLY TO THE EAST DUE
TO THE STEERING WINDS ALOFT. THIS IS A DRAMATIC SHIFT IN DIRECTION
FROM WHAT STORMS HAVE BEEN DOING OVERNIGHT...BUT IT MAKES SENSE IN
THE CONTEXT OF WHAT WAS DESCRIBED ABOVE.
THE MAIN POINT OF UNCERTAINTY THIS MORNING IS: WILL
THUNDERSTORMS BECOME ORGANIZED ENOUGH TO MOVE AS A SYSTEM?
THAT IS LARGELY UNKNOWN BECAUSE JUST LOOKING AT THE STORMS ON
RADAR IS NOT ENOUGH TO DETERMINE HOW STRONG THE COLD POOL WILL
GET...BUT THE FACT THAT THE HRRR AND THE TEXAS TECH WRF BOTH
ADVERTISE A DRAMATIC SHIFT TO THE SOUTH OF THUNDERSTORMS TOWARDS
THE RED RIVER AROUND SUNRISE GIVES CONFIDENCE IN THIS SOLUTION.
WENT AHEAD AND PLACED A VERY SMALL AREA OF 20 POPS IN THE FORECAST
FROM JUST NORTH OF SHERMAN EXTENDING TO THE SOUTHEAST INCLUDING
MUCH OF LAMAR COUNTY. IF THE STORMS DO MOVE TO THE SOUTH AS THESE
HIGH RESOLUTION MODELS INDICATE...THEY WILL BE IN THEIR
DISSIPATING STAGES BY THE TIME THEY CROSS THE RED RIVER WELL
AFTER SUNRISE THIS MORNING...SO NO STRONG OR SEVERE WEATHER IS
EXPECTED AT THIS TIME.
THIS AFTERNOON...MODELS CONTINUE TO CONSISTENTLY SHOW A SURGE OF
TROPICAL MOISTURE TO THE NORTHWEST FROM THE TX GULF COAST THIS
AFTERNOON. THIS SURGE OF MOISTURE APPEARS TO BE ASSOCIATED WITH A
SUBTLE BUT IMPORTANT MID-LEVEL WIND SHIFT ASSOCIATED WITH DOLLY
MOVING NORTHWEST TOWARDS THE NORTHERN MEXICO GULF COAST. THIS
DEEPER TROPICAL MOISTURE IS EXPECTED TO REMAIN SOUTH OF THE
INTERSTATE 20 CORRIDOR THIS AFTERNOON...SO REORIENTED POPS A BIT
TO HIGHLIGHT THE SOUTHERN HALF OF THE CWA. IN GENERAL...THERE IS
STILL NO OBVIOUS LIFT...SO THE COVERAGE OF STORMS WILL PROBABLY BE
ISOLATED IN NATURE...AND LEFT POPS AT THE 20 PERCENT LEVEL FOR NOW.
WEDNESDAY THROUGH FRIDAY...DOLLY IS EXPECTED TO MAKE LANDFALL OVER
NORTHERN MEXICO LATE THIS EVENING...AND THEN CONTINUE OFF TO THE
WEST-NORTHWEST THROUGH THE END OF THE WEEK. MODELS SEEM TO SEND
THE DEEPER MID-LEVEL TROPICAL MOISTURE PLUME TO THE WEST WITH
DOLLY...SO WENT AHEAD AND REMOVED POPS FROM THE FORECAST ON
WEDNESDAY AFTERNOON ACROSS THE SOUTHERN CWA AND LEFT THE REMAINDER
OF THE FORECAST DRY. WEAK UPPER LEVEL RIDGING IS THE DOMINANT
FEATURE DURING THIS TIME FRAME...SO EXPECT SUBSIDENCE TO WIN OUT
IN KEEPING THINGS DRY ACROSS NORTH AND CENTRAL TEXAS.
THIS WEEKEND...MODELS CONTINUE TO HINT AT A COLD FRONT MOVING
SOUTH OF THE RED RIVER SOMETIME SATURDAY AFTERNOON THROUGH SUNDAY
MORNING. MODELS STILL SEEM TO INDICATE THAT THE PRIMARY REASON
THAT THE FRONT MAKES IT SOUTH OF THE RED RIVER IS DUE TO
PERSISTENT THUNDERSTORM ACTIVITY ALONG THE FRONT LATE THIS WEEK.
IF THE FRONTAL MOTION IS REALLY DEPENDENT UPON PERSISTENT
THUNDERSTORM ACTIVITY...CONFIDENCE IN THE TIMING AND PLACEMENT OF
THE FRONT IS GOING TO REMAIN LOW UNTIL LATE THIS WEEK.
THE BIGGEST REASON FOR OPTIMISM IN THE FRONT MAKING IT THIS FAR
SOUTH IS OBSERVING WHAT HAPPENS TODAY. IF MCS ACTIVITY FROM THE
OK/KS BORDER ACTUALLY SURGES SOUTH THIS MORNING...IT BECOMES EASY
TO SEE HOW PERSISTENT STORMS TO OUR NORTH CAN SEND A STRONG
OUTFLOW BOUNDARY/FRONT ACROSS NORTH TEXAS UNDER WEAK RIDGING
ALOFT. THE FRONT IS MOST LIKELY TO BE IN PLACE OVER THE CWA ON
SUNDAY...SO LEFT POPS MAINLY ALONG AND NORTH OF INTERSTATE 20 ON
SATURDAY...AND KEPT THEM BROAD BRUSHED OVER THE ENTIRE CWA ON
SUNDAY.
EARLY NEXT WEEK...THE FRONT...ASSUMING IT MAKES IT HERE THIS
WEEKEND...WILL PROBABLY DISSIPATE BY MONDAY. BECAUSE THE FRONT
DOES NOT REPRESENT A TRUE AIRMASS REPLACEMENT...THAT IS...THERE IS
NO CANADIAN/OR SIGNIFICANTLY COOL AIR TO THE NORTH OF THIS
FRONT...IT WILL UNDERGO FRONTOLYSIS AND LOSE DEFINITION QUICKLY
UNDER RIDGING ALOFT. LEFT THE FORECAST FOR EARLY NEXT WEEK DRY AS
A RESULT.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 97 77 96 77 96 / 10 5 5 5 0
WACO, TX 98 75 97 74 97 / 20 20 10 5 5
PARIS, TX 92 72 91 72 92 / 20 10 5 5 0
DENTON, TX 96 75 95 74 95 / 10 5 5 0 0
MCKINNEY, TX 95 74 94 74 94 / 10 5 5 5 0
DALLAS, TX 97 78 96 78 96 / 10 5 5 5 0
TERRELL, TX 96 76 96 75 96 / 10 10 5 5 0
CORSICANA, TX 97 76 96 75 96 / 20 20 10 5 5
TEMPLE, TX 98 72 97 73 97 / 20 20 10 5 5
MINERAL WELLS, TX 97 73 96 72 96 / 10 5 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/75
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1232 PM CDT TUE SEP 2 2014
.AVIATION...
THERE REMAINS A SMALL POSSIBILITY OF ISOLATED THUNDER DEVELOPING
NEAR A WEAK FRONTAL BOUNDARY THAT WILL PULL UPSTATIONARY SOUTH OF
A CLOVIS TO AMARILLO LINE. SUPPRESSION FROM UPPER LEVEL HIGH
PRESSURE WILL FOR THE MOST PART HELP THE CAPPING INVERSION REMAIN
STRONG...BUT MODELS STILL HAVE A WEAK SIGNAL OF SOME CONVECTION
DEVELOPING IN AN AREA OF LOW LEVEL CONVERGENCE NEAR THE BOUNDARY.
LONG STORY SHORT IS COVERAGE WILL BE VERY LIMITED...IF ANY AT
ALL...AND WILL KEEP OUT OF BOTH TAFS.
OTHER ITEM OF NOTE IS THE POSSIBILITY OF STRATUS MAKING A RUN INTO
THE FCST AREA LATE TONIGHT. WILL GET THE BALL ROLLING BY INSERTING
A TEMPO MVFR MENTION IN THE KLBB TAF.
&&
.PREV DISCUSSION... /ISSUED 639 AM CDT TUE SEP 2 2014/
AVIATION...
SOUTHERLY SURFACE WINDS AND VFR CONDITIONS SHOULD PREVAIL OVER
MOST OF THE NEXT 24 HOURS. HOWEVER...THERE IS A SMALL CHANCE OF
-TSRA IN THE VICINITY OF EITHER TERMINAL BETWEEN ABOUT 20 UTC AND
03 UTC. IN ADDITION...A WEAK FRONT COULD PRODUCE A TEMPORARY WIND
SHIFT AT KCDS AROUND 14-15 UTC...BUT CONFIDENCE IS VERY LOW.
PREV DISCUSSION... /ISSUED 355 AM CDT TUE SEP 2 2014/
SHORT TERM...
3 AM TEMPS WERE STILL IN THE LOWER 80S ACROSS MUCH OF THE SOUTHERN
SOUTH PLAINS INTO THE ROLLING PLAINS...WHICH ISN/T SURPRISING GIVEN
THE RECORD-SETTING WARMTH ACROSS THE AREA ON LABOR DAY. A WEAK COLD
FRONT WAS LOCATED NEAR I-40...AND THERE WAS EVEN AN AREA OF LOW
CLOUDS DEVELOPING NORTH OF THE FRONT ACROSS THE OKLA AND NRN TX
PANHANDLES. ALOFT...A SHORTWAVE TROUGH IS MOVING FROM THE CENTRAL
PLAINS INTO THE MIDWEST...WITH ONLY A WEAK REFLECTION INTO THE SRN
HIGH PLAINS. THE FRONT IS EXPECTED TO MAKE SOME SWD PROGRESS THIS
MORNING ACROSS THE WEST BEFORE STALLING/WASHING OUT THIS
AFTERNOON...WITH A WEAK SURFACE LOW DEVELOPING ACROSS THE WESTERN
SPLNS. THIS IN TURN SHOULD PRODUCE A WEAKLY CONVERGENT ZONE FROM THE
CENTRAL SPLNS TO THE SOUTH-CENTRAL TX PANHANDLE...ALONG WITH A
DIFFUSE DRYLINE. WITH LITTLE IF ANY UPPER-LEVEL SUPPORT...WE/LL HAVE
TO RELY ON SURFACE-BASED LIFT TO GENERATE ANY MOIST CONVECTION
TODAY. KLBB FCST SOUNDING SHOWS A WEAKLY CAPPED PROFILE THIS
AFTERNOON...WITH NO CAP REMAINING FARTHER TO THE NORTH-NORTHEAST.
THERE IS NOT A WHOLE LOT OF QPF SIGNAL IN MODEL SOLUTIONS...BUT THE
06 UTC HRRR AND RAP RUNS INDICATE ISOLATED DEVELOPMENT AS WELL AS
THE SREF...WHICH SOMEWHAT BULLSEYES THE CAPROCK CANYONS AREA. WE
WILL RUN WITH A 15-20 PERCENT CHANCE OF T-STORMS...CENTERED ACROSS
BRISCOE COUNTY...AND ROUGHLY EXTENDING WEST TO I-27 AND SOUTH TO
NEAR HWY 82. SHEAR APPEARS TO BE TOO WEAK TO SUPPORT MORE THAN
PULSE-TYPE NON-SEVERE STORMS...BUT ML CAPES NEARING 2000 J/KG COULD
SUPPORT SMALL HAIL...LOCALIZED WIND GUSTS TO 50 MPH...AND A BRIEF
DOWNPOUR. STORMS SHOULD DIMINISH QUICKLY THIS EVENING WITH THE LOSS
OF SFC-BASED INSTABILITY. SKIES SHOULD BE MOSTLY CLEAR TONIGHT
ALTHOUGH SOME LOW STRATUS COULD INVADE FROM THE SOUTH EARLY WED
MORNING.
AS FOR TEMPS...FORTUNATELY WE SHOULD SEE THE HEAT OF THE PAST TWO
DAYS BACK DOWN A BIT...ALTHOUGH WE WOULDN/T BE SURPRISED TO SEE A
FEW LOCATIONS HIT 100 DEGREES IN THE LOW ROLLING PLAINS. HIGH TEMPS
MAY ONLY REACH THE LOWER 90S IN THE FAR SW TX PANHANDLE DUE TO THE
WEAK FRONT/S INFLUENCE...WITH MIDDLE TO UPPER 90S EXPECTED ELSEWHERE.
LONG TERM...
THE EXTENDED FORECAST FEATURES A WELCOME COOLING TREND EARLY ON WITH
INCREASING RAIN CHANCES BY THE WEEKEND.
INITIALLY...THE WESTERN EXTENT OF A LONGITUDINALLY BROAD UPPER RIDGE
WILL HOLD SWAY OVER WEST TEXAS MID/LATE WEEK. THIS RIDGE WILL
PROVIDE DRY AND WARM WEATHER...THOUGH DECREASING 1000-500 MB
THICKNESSES AND 850 MB TEMPERATURES PROMISE A GRADUAL COOLING TREND.
THINGS MAY EVENTUALLY BECOME MORE INTERESTING LATE WEEK INTO THE
WEEKEND THOUGH THIS WILL BE AT LEAST PARTIALLY CONTINGENT ON WHETHER
OR NOT A COLD FRONT MOVING THROUGH THE PLAINS CAN SETTLE INTO THE
SOUTH PLAINS. THE COLD FRONT WILL MAKE ITS FIRST RUN SOUTHWARD
BEHIND A POTENT SHORTWAVE TROUGH RIDING ACROSS THE NORTHERN TIER OF
THE NATION AND SOUTHERN CANADA WEDNESDAY AND THURSDAY. CURRENT NWP
HOLDS THE FRONT TO OUR NORTH ON FRIDAY...AS INCREASING AMOUNTS OF
TROPOSPHERIC MOISTURE /POTENTIALLY ENHANCED BY REMNANTS OF DOLLY
AND A TAP OFF A TROPICAL CYCLONE YET TO FORM IN THE EASTERN
PACIFIC/ ARE FUNNELED AROUND THE RIDGE INTO THE DESERT SOUTHWEST.
THE BEST RAIN CHANCES WILL LIKELY REMAIN FOCUSED TO NORTH AND WEST
FRIDAY INTO FRIDAY NIGHT...AND WE HAVE DECREASED POPS SOMEWHAT
OVER THIS PERIOD.
THE LATEST ITERATION OF THE GFS AND ECMWF NOW TEND TO KEEP THE UPPER
RIDGE CENTERED CLOSE ENOUGH THROUGH THE WEEKEND TO MAKE IT A LITTLE
MORE UNCERTAIN WHETHER WE WILL FULLY BE ABLE TO TAP THE SUB-TROPICAL
AND TROPICAL MOISTURE. EVEN SO...THE NWP SUGGESTS THE OUTFLOW
AIDED FRONT WILL SAG INTO THE SOUTH PLAINS SOMETIME OVER THE
WEEKEND /AS EARLY AS FRIDAY NIGHT WITH THE ECMWF OR NOT UNTIL
SATURDAY NIGHT IN THE GFS/. REGARDLESS...IF THE FRONT CAN MAKE IT
INTO THE CWA IT WILL BRING MORE SIGNIFICANT COOLING ALONG WITH
ENHANCED RAIN CHANCES. GIVEN THE UNKNOWNS...WE HAVE NOT MADE MANY
ADJUSTMENTS TO THE FORECAST OVER THE WEEKEND AND HAVE MAINTAINED
THE HIGHEST POPS SATURDAY NIGHT...WHEN CONFIDENCE IS HIGHEST OF
THE QUASI-STATIONARY FRONT RESIDING SOMEWHERE LOCALLY.
THE FRONT WILL THEN LIFT BACK NORTHWARD EARLY NEXT WEEK AS PRESSURES
FALL ACROSS THE HIGH PLAINS...DOWNSTREAM OF A WESTERN STORM SYSTEM.
THIS WILL RESULT IN WARMER AND DRIER WEATHER FOR WEST TEXAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 92 64 93 64 89 / 10 10 10 10 10
TULIA 95 67 94 66 90 / 20 10 10 10 0
PLAINVIEW 94 66 93 67 90 / 20 10 0 0 0
LEVELLAND 95 67 93 67 89 / 10 10 10 10 10
LUBBOCK 97 70 93 68 90 / 10 10 0 0 0
DENVER CITY 97 67 93 67 89 / 10 10 10 10 10
BROWNFIELD 97 68 93 68 90 / 10 10 0 0 10
CHILDRESS 98 72 97 73 96 / 10 10 0 0 0
SPUR 97 69 96 71 93 / 10 10 0 0 10
ASPERMONT 98 73 98 73 96 / 10 10 0 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1218 PM CDT TUE SEP 2 2014
.AVIATION...
/18Z TAFS/
Expect VFR conditions through the next 12 hours with
gusty south southwest winds during the afternoon and early
evening. the return of MVFR CIGS will be likely early tomorrow
morning at KJCT, KBBD, and KSOA terminals. Low CIGS will burn off
as we approach noon tomorrow.
&&
.PREV DISCUSSION... /ISSUED 627 AM CDT TUE SEP 2 2014/
AVIATION...
/12Z TAFS/
VFR conditions should prevail across most West Central Texas
terminals through the period. However, we are seeing the expected
MVFR stratus developing on low cloud imagery, although remaining
pretty patchy at this point. Suspect that it will expand a little
more through sunrise, and then quickly dissipate. Even at those
locations it does effect, it will be a move in and out quickly
type of feature. Otherwise, gusty south winds through daylight
hours with just a scattered afternoon cu field developing.
PREV DISCUSSION... /ISSUED 354 AM CDT TUE SEP 2 2014/
SHORT TERM...
(Today and Tonight)
Another mild night ongoing across West Central Texas, with south
winds remaining strong enough to keep temperatures from dropping
very much. Readings still right around 80 degrees at 3 AM (08Z).
Models do indicate that some patchy low cloudiness will develop by
sunrise and spread northward into the area, with low cloud satellite
imagery showing some of this starting to develop across portions of
Central Texas.
Another hot day in store for the area, with the upper level ridge of
high pressure in control. The 00Z NAM showed some convection across
West Central Texas this afternoon, but the GFS is dry. Both the TTU
WRF and the HRRR both show a similar pattern, scattered sea breeze
activity pushing well inland today, but dissipating at sunset across
Central Texas. Thus, will not insert PoPs into the forecast.
After readings above the 100 degree mark at San Angelo and
Abilene, models indicate a slight cooling at 850MB today as a
little cooler and more moist air mass from the Gulf of Mexico
slides into the area. Will keep afternoon highs below the 100
degree mark, but still a degree or two above guidance. Mild again
tonight as south winds keep temperatures from dropping very
quickly. Again, stayed just a little above guidance, as it has
been too cool for the last several days.
LONG TERM...
Surface temperatures fall 2 to 3 degrees F Wednesday as 850 MB
temperatures fall another 1 to 2 degrees Celsius. Tropical Storm
Dolly in the Bay of Campeche is expected to move into Mexico
early Wednesday, and may send weak disturbances/moisture
northward to affect the I-10 corridor Thursday and Friday. This
is indicated mainly by the EC model, as the GFS model is dry and
the NAM model nearly so. Will keep rain chances out of forecast
for this time period, given the uncertainty and limited agreement
in the models.
For Saturday night into Sunday, however, both the GFS and EC
modes are still indicating a weak cold front to bring a slight
chance of showers and thunderstorms. Forecast already has rain
chances in for this time period, and will maintain them.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 100 76 96 74 95 / 5 5 5 5 5
San Angelo 98 75 95 74 94 / 5 5 10 10 10
Junction 95 77 93 74 93 / 10 10 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/18
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1026 AM CDT TUE SEP 2 2014
.UPDATE...
SEE MORNING UPDATE.
&&
.DISCUSSION...
12Z SOUNDINGS SHOW PW VALUES BETWEEN 2.1 AND 2.2 INCHES AND THIS
IS SUPPORTED BY GPS MET DATA, CONVECTIVE TEMPS ARE BETWEEN 86 AND
88 DEGREES TODAY AND THIS THRESHOLD WILL BE MET EASILY. A WELL
DEVELOPED S/WV EXTENDS FROM CENTRAL ARKANSAS INTO CENTRAL TEXAS
WHICH SERVE AS ANOTHER FOCUS FOR SHRA/TSRA. UPPER LEVEL RIDING HAS
INCHED CLOSER TO SE TX WHICH WILL IMPART A BIT OF SUBSIDENCE. THE
RAP IS VERY AGGRESSIVE WITH RAINFALL THIS AFTN WHILE THE
HRRR/ARW-EAST REMAIN MORE BENIGN. THE RAP WAS OVERDONE YESTERDAY
AND DID NOT INITIALIZE ALL THAT WELL SO HAVE LEANED TOWARD A HRRR/WRF
BLEND. CHANCE POPS LOOK APPROPRIATE SO NO CHANGES TO THE POP/WX
GRIDS. DID BUMP MAX T GRIDS UP A FEW DEGREES TO MATCH TRENDS/OBS.
AS FOR TS DOLLY...THE STORM WILL PROBABLY MAKE LANDFALL A BIT
EARLIER...SOMETIME THIS EVENING. THE MAIN EFFECT FOR SE TX WILL BE
INCREASING SWELLS OVER THE OFFSHORE MARINE ZONES AND A 1.0-1.5
FOOT BUMP UP IN TIDE LEVELS. NEW ZONES OUT BY 1030 AM. 43
&&
.PREV DISCUSSION... /ISSUED 629 AM CDT TUE SEP 2 2014/
AVIATION...
MOSTLY SCT CLOUDS ACROSS THE AREA THIS MORNING. SHRA/TSRA MOVING TO
THE NNW OUT OF THE GULF ARE SO FAR HAVING TROUBLE MAKING IT PAST THE
COASTAL COUNTIES. ACTIVITY SHOULD SPREAD/DEVELOP FURTHER INLAND LATER
THIS MORNING AND THIS AFTERNOON DUE TO DAYTIME HEATING AND INCREASING
INSTABILITY. GOING WITH VCTS/TSRA FOR THIS MORNING NEAR THE COAST AND
INLAND THIS AFTERNOON. THINGS SHOULD QUIET DOWN THIS EVENING WITH THE
LOSS OF HEATING. MVFR CEILING DEVELOPMENT POSSIBLE LATE TONIGHT THROUGH
EARLY WEDNESDAY MORNING. 42
PREV DISCUSSION... /ISSUED 405 AM CDT TUE SEP 2 2014/
DISCUSSION...
A FEW SHOWERS ARE MOVING NORTHWARD ACROSS THE COASTAL WATERS THIS
MORNING IN ASSOCIATION WITH AN AREA OF DEEPER MOISTURE WHICH IS
APPROACHING THE UPPER TEXAS COAST. FURTHER TO THE SOUTH...TD 5 HAS
STRENGTHENED INTO TROPICAL STORM DOLLY THIS MORNING. THE CENTER OF
THE SYSTEM HAS FORMED A BIT FURTHER NORTH THAT PREVIOUSLY EXPECTED
WHICH HAS CAUSED A CORRESPONDING SHIFT IN THE FORECAST TRACK. THE
ONLY ADDITIONAL IMPACTS TO SOUTHEAST TEXAS WILL BE SOME SLIGHTLY
HIGHER SEAS OFFSHORE AS THE NEW TRACK STILL TAKES THE SYSTEM INTO
MEXICO WELL SOUTH OF THE BORDER.
EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP INLAND LATER
THIS MORNING AS MOISTURE STREAMS BACK INTO THE REGION. COVERAGE
SHOULD INCREASE ACROSS OUR NORTHERN COUNTIES LATE THIS AFTERNOON
AS A PASSING SHORTWAVE BRINGS ADDITIONAL LIFT TO THE REGION. GIVEN
THE RICH MOISTURE A FEW BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE
WITH THE ACTIVITY TODAY. HIGH TEMPERATURES SHOULD REMAIN IN THE
LOW TO MID 90S AREAWIDE WITH THE PRECIPITATION AND GREATER CLOUD
COVER.
ONLY SLIGHT CHANGES FOR THE MID TO EXTENDED RANGE FORECAST THIS
MORNING. THE UPPER LEVEL PATTERN OVERHEAD REMAINS RELATIVELY
UNCHANGED THROUGH THE WEEK WITH A BROAD FLAT RIDGE ACROSS THE
SOUTHERN UNITED STATES. THIS WILL ALLOW FOR CONTINUED DIURNALLY
DRIVEN SHOWERS AND THUNDERSTORMS WITH HIGH TEMPERATURES IN THE LOW
TO MID 90S...NEAR THE NORMALS FOR THE FIRST WEEK OF SEPTEMBER. 38
MARINE...
TROPICAL STORM DOLLY IS LOCATED IN THE BAY OF CAMPECHE EARLY
THIS MORNING. BASED ON THE CURRENT FORECAST...DOLLY IS EXPECTED
TO APPROACH THE COAST OF MEXICO BY TONIGHT AND MOVE INLAND BY
WEDNESDAY MORNING. BUILDING SEAS CAN BE EXPECTED ALONG THE UPPER
TEXAS COAST. CAUTION FLAGS ARE CURRENTLY IN EFFECT...AND ADVISORIES
MIGHT BE NEEDED IF SEAS BUILD HIGHER THAN ANTICIPATED. PERIODS OF
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED ACROSS OUR AREA OVER THE
NEXT COUPLE OF DAYS. TOWARD THE END OF THE WEEK...EXPECT WEAKENING
ONSHORE WINDS AND LOWERING SEAS. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 94 75 95 75 94 / 30 20 20 10 20
HOUSTON (IAH) 93 77 93 76 92 / 40 20 30 10 20
GALVESTON (GLS) 89 81 91 81 90 / 30 20 30 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 8 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
627 AM CDT TUE SEP 2 2014
.AVIATION...
/12Z TAFS/
VFR conditions should prevail across most West Central Texas
terminals through the period. However, we are seeing the expected
MVFR stratus developing on low cloud imagery, although remaining
pretty patchy at this point. Suspect that it will expand a little
more through sunrise, and then quickly dissipate. Even at those
locations it does effect, it will be a move in and out quickly
type of feature. Otherwise, gusty south winds through daylight
hours with just a scattered afternoon cu field developing.
&&
.PREV DISCUSSION... /ISSUED 354 AM CDT TUE SEP 2 2014/
SHORT TERM...
(Today and Tonight)
Another mild night ongoing across West Central Texas, with south
winds remaining strong enough to keep temperatures from dropping
very much. Readings still right around 80 degrees at 3 AM (08Z).
Models do indicate that some patchy low cloudiness will develop by
sunrise and spread northward into the area, with low cloud satellite
imagery showing some of this starting to develop across portions of
Central Texas.
Another hot day in store for the area, with the upper level ridge of
high pressure in control. The 00Z NAM showed some convection across
West Central Texas this afternoon, but the GFS is dry. Both the TTU
WRF and the HRRR both show a similar pattern, scattered sea breeze
activity pushing well inland today, but dissipating at sunset across
Central Texas. Thus, will not insert PoPs into the forecast.
After readings above the 100 degree mark at San Angelo and
Abilene, models indicate a slight cooling at 850MB today as a
little cooler and more moist air mass from the Gulf of Mexico
slides into the area. Will keep afternoon highs below the 100
degree mark, but still a degree or two above guidance. Mild again
tonight as south winds keep temperatures from dropping very
quickly. Again, stayed just a little above guidance, as it has
been too cool for the last several days.
LONG TERM...
Surface temperatures fall 2 to 3 degrees F Wednesday as 850 MB
temperatures fall another 1 to 2 degrees Celsius. Tropical Storm
Dolly in the Bay of Campeche is expected to move into Mexico
early Wednesday, and may send weak disturbances/moisture
northward to affect the I-10 corridor Thursday and Friday. This
is indicated mainly by the EC model, as the GFS model is dry and
the NAM model nearly so. Will keep rain chances out of forecast
for this time period, given the uncertainty and limited agreement
in the models.
For Saturday night into Sunday, however, both the GFS and EC
modes are still indicating a weak cold front to bring a slight
chance of showers and thunderstorms. Forecast already has rain
chances in for this time period, and will maintain them.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 100 76 96 74 95 / 5 5 5 5 5
San Angelo 98 75 95 74 94 / 5 5 10 10 10
Junction 95 77 93 74 93 / 10 10 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
CONTINUE ON WITH THE FORECAST DISCUSSION...
IN A BASIC SENSE...THE MOVEMENT OF THUNDERSTORM SYSTEMS IS
CONTROLLED BY THE AVERAGE OF THE WINDS ALOFT...OFTEN REFERRED TO
AS THE STEERING WINDS. IN MOST CASES...THUNDERSTORMS WILL SIMPLY
MOVE IN THE DIRECTION IN WHICH THE WINDS ALOFT ARE BLOWING.
HOWEVER THE SECOND COMPONENT TO CONSIDER IS OFTEN REFERRED TO AS
THE PROPAGATION COMPONENT OF STORM MOTION. PROPAGATION INFLUENCES
STORM MOTION BY CHANGING THE DIRECTION OF MOTION OF A THUNDERSTORM
SYSTEM IN THE DIRECTION THAT NEW THUNDERSTORMS DEVELOP. THIS IS
THE MORE COMPLICATED FACTOR TO UNDERSTAND...BUT IN GENERAL...NEW
THUNDERSTORMS TEND TO DEVELOP IN THE OPPOSITE DIRECTION OF THE LOW
LEVEL JET. ON A DAY LIKE TODAY...WHERE THE STEERING WINDS ARE
SOMEWHAT LIGHT DUE TO UPPER LEVEL RIDGING OVER TEXAS...BUT THE
LOW-LEVEL JET IS RELATIVELY STRONG...THE PROPAGATION COMPONENT CAN
DOMINATE THE DIRECTION IN WHICH THE THUNDERSTORM SYSTEM MOVES. FOR
TODAY...THE STEERING WINDS ARE SOMEWHAT LIGHT AND WOULD INDICATE
AN EASTERLY STORM MOTION. THIS IS WHY THE STORMS ARE JUST SORT OF
SITTING THERE ALONG THE FRONT AS OF 3 AM. HOWEVER IF THIS RESULTS
IN A STRONG ENOUGH COLD POOL (A COLLECTION OF RAIN COOLED AIR)
THIS COLD POOL COULD START TO SURGE SOUTH...CAUSING NEW STORMS TO
DEVELOP IN THE OPPOSITE DIRECTION OF THE LOW-LEVEL JET. SINCE THE
LOW-LEVEL JET EXTENDS FROM OUR CWA TO THE FRONT...THE WHOLE
COMPLEX OF STORMS COULD START TO MOVE SOUTH DIRECTLY TOWARDS THE
RED RIVER...BUT WILL STILL MOVE AT LEAST SLIGHTLY TO THE EAST DUE
TO THE STEERING WINDS ALOFT. THIS IS A DRAMATIC SHIFT IN DIRECTION
FROM WHAT STORMS HAVE BEEN DOING OVERNIGHT...BUT IT MAKES SENSE IN
THE CONTEXT OF WHAT WAS DESCRIBED ABOVE.
THE MAIN POINT OF UNCERTAINTY THIS MORNING IS: WILL
THUNDERSTORMS BECOME ORGANIZED ENOUGH TO MOVE AS A SYSTEM?
THAT IS LARGELY UNKNOWN BECAUSE JUST LOOKING AT THE STORMS ON
RADAR IS NOT ENOUGH TO DETERMINE HOW STRONG THE COLD POOL WILL
GET...BUT THE FACT THAT THE HRRR AND THE TEXAS TECH WRF BOTH
ADVERTISE A DRAMATIC SHIFT TO THE SOUTH OF THUNDERSTORMS TOWARDS
THE RED RIVER AROUND SUNRISE GIVES CONFIDENCE IN THIS SOLUTION.
WENT AHEAD AND PLACED A VERY SMALL AREA OF 20 POPS IN THE FORECAST
FROM JUST NORTH OF SHERMAN EXTENDING TO THE SOUTHEAST INCLUDING
MUCH OF LAMAR COUNTY. IF THE STORMS DO MOVE TO THE SOUTH AS THESE
HIGH RESOLUTION MODELS INDICATE...THEY WILL BE IN THEIR
DISSIPATING STAGES BY THE TIME THEY CROSS THE RED RIVER WELL
AFTER SUNRISE THIS MORNING...SO NO STRONG OR SEVERE WEATHER IS
EXPECTED AT THIS TIME.
THIS AFTERNOON...MODELS CONTINUE TO CONSISTENTLY SHOW A SURGE OF
TROPICAL MOISTURE TO THE NORTHWEST FROM THE TX GULF COAST THIS
AFTERNOON. THIS SURGE OF MOISTURE APPEARS TO BE ASSOCIATED WITH A
SUBTLE BUT IMPORTANT MID-LEVEL WIND SHIFT ASSOCIATED WITH DOLLY
MOVING NORTHWEST TOWARDS THE NORTHERN MEXICO GULF COAST. THIS
DEEPER TROPICAL MOISTURE IS EXPECTED TO REMAIN SOUTH OF THE
INTERSTATE 20 CORRIDOR THIS AFTERNOON...SO REORIENTED POPS A BIT
TO HIGHLIGHT THE SOUTHERN HALF OF THE CWA. IN GENERAL...THERE IS
STILL NO OBVIOUS LIFT...SO THE COVERAGE OF STORMS WILL PROBABLY BE
ISOLATED IN NATURE...AND LEFT POPS AT THE 20 PERCENT LEVEL FOR NOW.
WEDNESDAY THROUGH FRIDAY...DOLLY IS EXPECTED TO MAKE LANDFALL OVER
NORTHERN MEXICO LATE THIS EVENING...AND THEN CONTINUE OFF TO THE
WEST-NORTHWEST THROUGH THE END OF THE WEEK. MODELS SEEM TO SEND
THE DEEPER MID-LEVEL TROPICAL MOISTURE PLUME TO THE WEST WITH
DOLLY...SO WENT AHEAD AND REMOVED POPS FROM THE FORECAST ON
WEDNESDAY AFTERNOON ACROSS THE SOUTHERN CWA AND LEFT THE REMAINDER
OF THE FORECAST DRY. WEAK UPPER LEVEL RIDGING IS THE DOMINANT
FEATURE DURING THIS TIME FRAME...SO EXPECT SUBSIDENCE TO WIN OUT
IN KEEPING THINGS DRY ACROSS NORTH AND CENTRAL TEXAS.
THIS WEEKEND...MODELS CONTINUE TO HINT AT A COLD FRONT MOVING
SOUTH OF THE RED RIVER SOMETIME SATURDAY AFTERNOON THROUGH SUNDAY
MORNING. MODELS STILL SEEM TO INDICATE THAT THE PRIMARY REASON
THAT THE FRONT MAKES IT SOUTH OF THE RED RIVER IS DUE TO
PERSISTENT THUNDERSTORM ACTIVITY ALONG THE FRONT LATE THIS WEEK.
IF THE FRONTAL MOTION IS REALLY DEPENDENT UPON PERSISTENT
THUNDERSTORM ACTIVITY...CONFIDENCE IN THE TIMING AND PLACEMENT OF
THE FRONT IS GOING TO REMAIN LOW UNTIL LATE THIS WEEK.
THE BIGGEST REASON FOR OPTIMISM IN THE FRONT MAKING IT THIS FAR
SOUTH IS OBSERVING WHAT HAPPENS TODAY. IF MCS ACTIVITY FROM THE
OK/KS BORDER ACTUALLY SURGES SOUTH THIS MORNING...IT BECOMES EASY
TO SEE HOW PERSISTENT STORMS TO OUR NORTH CAN SEND A STRONG
OUTFLOW BOUNDARY/FRONT ACROSS NORTH TEXAS UNDER WEAK RIDGING
ALOFT. THE FRONT IS MOST LIKELY TO BE IN PLACE OVER THE CWA ON
SUNDAY...SO LEFT POPS MAINLY ALONG AND NORTH OF INTERSTATE 20 ON
SATURDAY...AND KEPT THEM BROAD BRUSHED OVER THE ENTIRE CWA ON
SUNDAY.
EARLY NEXT WEEK...THE FRONT...ASSUMING IT MAKES IT HERE THIS
WEEKEND...WILL PROBABLY DISSIPATE BY MONDAY. BECAUSE THE FRONT
DOES NOT REPRESENT A TRUE AIRMASS REPLACEMENT...THAT IS...THERE IS
NO CANADIAN/OR SIGNIFICANTLY COOL AIR TO THE NORTH OF THIS
FRONT...IT WILL UNDERGO FRONTOLYSIS AND LOSE DEFINITION QUICKLY
UNDER RIDGING ALOFT. LEFT THE FORECAST FOR EARLY NEXT WEEK DRY AS
A RESULT.
CAVANAUGH
&&
.AVIATION...
/ISSUED 1130 PM CDT MON SEP 1 2014/
VFR CONDITIONS AREA-WIDE WILL BECOME BRIEFLY INTERRUPTED BY A
PERIOD OF MVFR DURING THE TUESDAY MORNING HOURS AS STRATUS SPREADS
NORTHWARD IN THE SOUTHERLY LOW LEVEL FLOW. WE HAVE NOW INCLUDED
MVFR CIGS INDISCRIMINATELY BASED ON THE MOST RECENT MODEL
DATA...WITH ONSET AT 08Z IN KACT AND 11-12Z IN THE METROPLEX. CIGS
SHOULD SCATTER OUT IN THE 15-17Z TIMEFRAME...OTHERWISE PERSISTENT
SOUTH TO SOUTHEAST WINDS CAN BE EXPECTED.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 97 77 96 77 96 / 5 5 5 5 0
WACO, TX 98 75 97 74 97 / 20 20 10 5 5
PARIS, TX 92 72 91 72 92 / 20 10 5 5 0
DENTON, TX 96 75 95 74 95 / 10 5 5 0 0
MCKINNEY, TX 95 74 94 74 94 / 10 5 5 5 0
DALLAS, TX 97 78 96 78 96 / 5 5 5 5 0
TERRELL, TX 96 76 96 75 96 / 10 10 5 5 0
CORSICANA, TX 97 76 96 75 96 / 20 20 10 5 5
TEMPLE, TX 98 72 97 73 97 / 20 20 10 5 5
MINERAL WELLS, TX 97 73 96 72 96 / 5 5 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
354 AM CDT TUE SEP 2 2014
.SHORT TERM...
(Today and Tonight)
Another mild night ongoing across West Central Texas, with south
winds remaining strong enough to keep temperatures from dropping
very much. Readings still right around 80 degrees at 3 AM (08Z).
Models do indicate that some patchy low cloudiness will develop by
sunrise and spread northward into the area, with low cloud satellite
imagery showing some of this starting to develop across portions of
Central Texas.
Another hot day in store for the area, with the upper level ridge of
high pressure in control. The 00Z NAM showed some convection across
West Central Texas this afternoon, but the GFS is dry. Both the TTU
WRF and the HRRR both show a similar pattern, scattered sea breeze
activity pushing well inland today, but dissipating at sunset across
Central Texas. Thus, will not insert PoPs into the forecast.
After readings above the 100 degree mark at San Angelo and
Abilene, models indicate a slight cooling at 850MB today as a
little cooler and more moist air mass from the Gulf of Mexico
slides into the area. Will keep afternoon highs below the 100
degree mark, but still a degree or two above guidance. Mild again
tonight as south winds keep temperatures from dropping very
quickly. Again, stayed just a little above guidance, as it has
been too cool for the last several days.
.LONG TERM...
Surface temperatures fall 2 to 3 degrees F Wednesday as 850 MB
temperatures fall another 1 to 2 degrees Celsius. Tropical Storm
Dolly in the Bay of Campeche is expected to move into Mexico
early Wednesday, and may send weak disturbances/moisture
northward to affect the I-10 corridor Thursday and Friday. This
is indicated mainly by the EC model, as the GFS model is dry and
the NAM model nearly so. Will keep rain chances out of forecast
for this time period, given the uncertainty and limited agreement
in the models.
For Saturday night into Sunday, however, both the GFS and EC
modes are still indicating a weak cold front to bring a slight
chance of showers and thunderstorms. Forecast already has rain
chances in for this time period, and will maintain them.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 100 76 96 74 95 / 5 5 5 5 5
San Angelo 98 75 95 74 94 / 5 5 10 10 10
Junction 95 77 93 74 93 / 10 10 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/04
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
355 AM CDT TUE SEP 2 2014
.SHORT TERM...
3 AM TEMPS WERE STILL IN THE LOWER 80S ACROSS MUCH OF THE SOUTHERN
SOUTH PLAINS INTO THE ROLLING PLAINS...WHICH ISN/T SURPRISING GIVEN
THE RECORD-SETTING WARMTH ACROSS THE AREA ON LABOR DAY. A WEAK COLD
FRONT WAS LOCATED NEAR I-40...AND THERE WAS EVEN AN AREA OF LOW
CLOUDS DEVELOPING NORTH OF THE FRONT ACROSS THE OKLA AND NRN TX
PANHANDLES. ALOFT...A SHORTWAVE TROUGH IS MOVING FROM THE CENTRAL
PLAINS INTO THE MIDWEST...WITH ONLY A WEAK REFLECTION INTO THE SRN
HIGH PLAINS. THE FRONT IS EXPECTED TO MAKE SOME SWD PROGRESS THIS
MORNING ACROSS THE WEST BEFORE STALLING/WASHING OUT THIS
AFTERNOON...WITH A WEAK SURFACE LOW DEVELOPING ACROSS THE WESTERN
SPLNS. THIS IN TURN SHOULD PRODUCE A WEAKLY CONVERGENT ZONE FROM THE
CENTRAL SPLNS TO THE SOUTH-CENTRAL TX PANHANDLE...ALONG WITH A
DIFFUSE DRYLINE. WITH LITTLE IF ANY UPPER-LEVEL SUPPORT...WE/LL HAVE
TO RELY ON SURFACE-BASED LIFT TO GENERATE ANY MOIST CONVECTION
TODAY. KLBB FCST SOUNDING SHOWS A WEAKLY CAPPED PROFILE THIS
AFTERNOON...WITH NO CAP REMAINING FARTHER TO THE NORTH-NORTHEAST.
THERE IS NOT A WHOLE LOT OF QPF SIGNAL IN MODEL SOLUTIONS...BUT THE
06 UTC HRRR AND RAP RUNS INDICATE ISOLATED DEVELOPMENT AS WELL AS
THE SREF...WHICH SOMEWHAT BULLSEYES THE CAPROCK CANYONS AREA. WE
WILL RUN WITH A 15-20 PERCENT CHANCE OF T-STORMS...CENTERED ACROSS
BRISCOE COUNTY...AND ROUGHLY EXTENDING WEST TO I-27 AND SOUTH TO
NEAR HWY 82. SHEAR APPEARS TO BE TOO WEAK TO SUPPORT MORE THAN
PULSE-TYPE NON-SEVERE STORMS...BUT ML CAPES NEARING 2000 J/KG COULD
SUPPORT SMALL HAIL...LOCALIZED WIND GUSTS TO 50 MPH...AND A BRIEF
DOWNPOUR. STORMS SHOULD DIMINISH QUICKLY THIS EVENING WITH THE LOSS
OF SFC-BASED INSTABILITY. SKIES SHOULD BE MOSTLY CLEAR TONIGHT
ALTHOUGH SOME LOW STRATUS COULD INVADE FROM THE SOUTH EARLY WED
MORNING.
AS FOR TEMPS...FORTUNATELY WE SHOULD SEE THE HEAT OF THE PAST TWO
DAYS BACK DOWN A BIT...ALTHOUGH WE WOULDN/T BE SURPRISED TO SEE A
FEW LOCATIONS HIT 100 DEGREES IN THE LOW ROLLING PLAINS. HIGH TEMPS
MAY ONLY REACH THE LOWER 90S IN THE FAR SW TX PANHANDLE DUE TO THE
WEAK FRONT/S INFLUENCE...WITH MIDDLE TO UPPER 90S EXPECTED ELSEWHERE.
&&
.LONG TERM...
THE EXTENDED FORECAST FEATURES A WELCOME COOLING TREND EARLY ON WITH
INCREASING RAIN CHANCES BY THE WEEKEND.
INITIALLY...THE WESTERN EXTENT OF A LONGITUDINALLY BROAD UPPER RIDGE
WILL HOLD SWAY OVER WEST TEXAS MID/LATE WEEK. THIS RIDGE WILL
PROVIDE DRY AND WARM WEATHER...THOUGH DECREASING 1000-500 MB
THICKNESSES AND 850 MB TEMPERATURES PROMISE A GRADUAL COOLING TREND.
THINGS MAY EVENTUALLY BECOME MORE INTERESTING LATE WEEK INTO THE
WEEKEND THOUGH THIS WILL BE AT LEAST PARTIALLY CONTINGENT ON WHETHER
OR NOT A COLD FRONT MOVING THROUGH THE PLAINS CAN SETTLE INTO THE
SOUTH PLAINS. THE COLD FRONT WILL MAKE ITS FIRST RUN SOUTHWARD
BEHIND A POTENT SHORTWAVE TROUGH RIDING ACROSS THE NORTHERN TIER OF
THE NATION AND SOUTHERN CANADA WEDNESDAY AND THURSDAY. CURRENT NWP
HOLDS THE FRONT TO OUR NORTH ON FRIDAY...AS INCREASING AMOUNTS OF
TROPOSPHERIC MOISTURE /POTENTIALLY ENHANCED BY REMNANTS OF DOLLY
AND A TAP OFF A TROPICAL CYCLONE YET TO FORM IN THE EASTERN
PACIFIC/ ARE FUNNELED AROUND THE RIDGE INTO THE DESERT SOUTHWEST.
THE BEST RAIN CHANCES WILL LIKELY REMAIN FOCUSED TO NORTH AND WEST
FRIDAY INTO FRIDAY NIGHT...AND WE HAVE DECREASED POPS SOMEWHAT
OVER THIS PERIOD.
THE LATEST ITERATION OF THE GFS AND ECMWF NOW TEND TO KEEP THE UPPER
RIDGE CENTERED CLOSE ENOUGH THROUGH THE WEEKEND TO MAKE IT A LITTLE
MORE UNCERTAIN WHETHER WE WILL FULLY BE ABLE TO TAP THE SUB-TROPICAL
AND TROPICAL MOISTURE. EVEN SO...THE NWP SUGGESTS THE OUTFLOW
AIDED FRONT WILL SAG INTO THE SOUTH PLAINS SOMETIME OVER THE
WEEKEND /AS EARLY AS FRIDAY NIGHT WITH THE ECMWF OR NOT UNTIL
SATURDAY NIGHT IN THE GFS/. REGARDLESS...IF THE FRONT CAN MAKE IT
INTO THE CWA IT WILL BRING MORE SIGNIFICANT COOLING ALONG WITH
ENHANCED RAIN CHANCES. GIVEN THE UNKNOWNS...WE HAVE NOT MADE MANY
ADJUSTMENTS TO THE FORECAST OVER THE WEEKEND AND HAVE MAINTAINED
THE HIGHEST POPS SATURDAY NIGHT...WHEN CONFIDENCE IS HIGHEST OF
THE QUASI-STATIONARY FRONT RESIDING SOMEWHERE LOCALLY.
THE FRONT WILL THEN LIFT BACK NORTHWARD EARLY NEXT WEEK AS PRESSURES
FALL ACROSS THE HIGH PLAINS...DOWNSTREAM OF A WESTERN STORM SYSTEM.
THIS WILL RESULT IN WARMER AND DRIER WEATHER FOR WEST TEXAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 92 64 93 64 89 / 10 10 10 10 10
TULIA 95 67 94 66 90 / 20 10 10 10 0
PLAINVIEW 94 66 93 67 90 / 20 10 0 0 0
LEVELLAND 95 67 93 67 89 / 10 10 10 10 10
LUBBOCK 97 70 93 68 90 / 10 10 0 0 0
DENVER CITY 97 67 93 67 89 / 10 10 10 10 10
BROWNFIELD 97 68 93 68 90 / 10 10 0 0 10
CHILDRESS 98 72 97 73 96 / 10 10 0 0 0
SPUR 97 69 96 71 93 / 10 10 0 0 10
ASPERMONT 98 73 98 73 96 / 10 10 0 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
149 AM EDT TUE SEP 2 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT INTO MUCH
OF TUESDAY. A WEAK COLD FRONT TRACKS SOUTHEAST INTO OUR AREA BY
TUESDAY EVENING...BEFORE STALLING ACROSS THE CAROLINAS AND WASHING
OUT ON WEDNESDAY. HIGH PRESSURE SETS BACK UP OVER THE EAST BY
FRIDAY WITH YET ANOTHER COLD FRONT MOVING TOWARD US THIS WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 138 AM EDT TUESDAY...
MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND POPS FOR THIS
MORNING.
AS OF 850 PM EDT MONDAY...
OTHER FOR ISOLATED SHRA/TSRA PASSING ACROSS THE FAR
NORTH...CONVECTION REMAINS LIMITED THIS EVENING AS SOUNDINGS SHOW
WEAK CAPPING ALOFT WITHIN A DEEP WESTERLY FLOW REGIME. THIS ALONG
WITH LACK OF DEEP INSTABILITY SHOULD KEEP THINGS MAINLY QUIET
OVERNIGHT WITH JUST SOME PATCHY FOG IN THE VALLEYS AND PERHAPS OUT
EAST. HOWEVER WITH THE LATEST HRRR TRACKING THE CURRENT ISOLATED
COVERAGE OVER GREENBRIER EAST TOWARD THE SOUTHERN SHENANDOAH
VALLEY...WILL LEAVE IN SOME LOW POPS ACROSS THE EXTREME NORTH SINCE
HEADING INTO SOME DECENT LEFTOVER CAPE DESPITE LOSS OF HEATING.
WILL ALSO CONTINUE SOME LOW CHANCES FAR NW LATE FOR ACTIVITY
COMING IN AHEAD OF THE UPSTREAM FRONT AROUND DAYBREAK. OTRW FEW
CHANGES OTHER THAN TO INCLUDE A BIT OF FOG AND BUMP UP TEMPS IN
SPOTS GIVEN SUCH A MUGGY OVERNIGHT.
ANOTHER SHORTWAVE AHEAD OF A FRONT SHIFTING SE INTO THE OHIO VALLEY
PASSES ACROSS TUESDAY MORNING. FOR NOW IT LOOKS LIKE THE WESTERN CWA
WILL SEE A CHANCE OF SHOWERS/ISOLATED TSRA DURING THE MORNING BUT
AGAIN EAST OF THE BLUE RIDGE LOOKS FEEBLE. THERE IS GOOD SUBSIDENCE
BEHIND THIS FEATURE BY 18Z TUESDAY BUT ANOTHER WAVE AND THE FRONT
ITSELF WILL EDGE CLOSER TOWARD TUE EVENING...WHICH WILL BRING A
BETTER THREAT OF SHOWERS AND STORMS TO THE MOUNTAINS WITH ISOLATED
TO WIDELY SCATTERED COVERAGE OVER THE FOOTHILLS AND PIEDMONT.
TUESDAY WILL BE HOT...WITH ENOUGH SUN TO SEND TEMPS INTO THE LOWER
TO MID 90S EAST...AND LOWER TO MID 80S WEST.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 224 PM EDT MONDAY...
A WEAK COLD FRONT SLIDES ACROSS THE REGION TUESDAY NIGHT...PUSHING
PRECIPITATION TO THE EAST COAST. HIGH PRESSURE BUILDS IN FROM THE
WEST THROUGH WEDNESDAY. THE ASSOCIATED DEW POINT FRONT AND DRIER AIR
IS LAGGING WAY BEHIND AND DOES NOT ENTER THE FORECAST AREA UNTIL
LATE WEDNESDAY MORNING. THIS DEW POINT FRONT MAY MAKE IT AS FAR AS
THE VA/NC BORDER WEDNESDAY AFTERNOON...THEN BEGINS TO RETREAT TO THE
NORTH WEDNESDAY NIGHT AND THURSDAY. SURFACE HIGH PRESSURE WILL KEEP
MOST OF THE AREA DRY BUT COULD SEE ISOLATED DIURNAL SHOWERS SOUTH OF
THE DEW POINT FRONT WEDNESDAY AFTERNOON/EVENING. AS THIS SURFACE
RIDGE DRIFTS OFF THE MID ATLANTIC COAST THURSDAY...SOUTHEAST FLOW
AND ATLANTIC MOISTURE WILL INCREASE THE CHANCE FOR SHOWERS FOR AREAS
ALONG AND EAST OF THE BLUE RIDGE...ESPECIALLY THE NORTH CAROLINA
HIGH COUNTY THURSDAY AFTERNOON. EVEN THOUGH FLOW IS WEAK
ALOFT...WARM SOUTHWEST FLOW WILL OVERRUN THIS RIDGE/INSITU WEDGE TO
PRODUCE A LOW STRATUS DECK AND A CHANCE FOR LIGHT RAIN/DRIZZLE FOR
AREAS EAST OF THE BLUE RIDGE OVERNIGHT THURSDAY.
TEMPERATURES WILL RANGE FROM THE UPPER 70S TO LOWER 80S ACROSS THE
MOUNTAINS AND UPPER 80S TO LOWER 90S EAST WEDNESDAY AFTERNOON.
EASTERLY FLOW THURSDAY WILL PRODUCE UNIFORM TEMPERATURES IN THE 80S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 248 PM EDT MONDAY...
HIGH PRESSURE EXITS THE MID ATLANTIC COAST ON FRIDAY AND WILL BE
REPLACED BY A LEE TROUGH. WITH AN UPPER LEVEL RIDGE ACROSS THE GULF
STATE TO THE SOUTHEAST COAST...NEARLY ZONAL FLOW MAY BRING A SHORT
WAVE OVER THE REGION FRIDAY. THIS SHORT WAVE WILL HELP SPARK
CONVECTION THROUGH THE AFTERNOON AND EVENING HOURS. IF THIS SHORT
WAVE DOES NOT MATERIALIZE...DIURNAL CONVECTION IS STILL POSSIBLE
WITH ABUNDANT MOISTURE...AFTERNOON HEATING AND A LEE TROUGH. FOR THE
WEEKEND...A COLD FRONT IS EXPECTED TO PASS OVER THE REGION SATURDAY
(GFS) OR SUNDAY (ECM). WITH A STUBBORN UPPER LEVEL RIDGE TO THE
SOUTH...FAVORING THE SLOWER ECM RUN. PREFRONTAL OR DIURNAL
CONVECTION IS POSSIBLE SATURDAY BUT WILL KEEP THE HIGHEST POPS WITH
THE FRONTAL PASSAGE SUNDAY. NOT QUITE SURE IF THE FRONT WILL
COMPLETE CLEAR THE FORECAST AREA AS THE UPPER LEVEL RIDGE CONTINUES
TO HANG ACROSS THE SOUTHERN STATES.
TEMPERATURES WILL REMAIN WARMER THAN NORMAL UNTIL THE FRONT CLEARS
THE AREA. ONCE THE FRONT PASSES...TEMPERATURES WILL RUN COOLER THAN
NORMAL WITH HIGHS IN THE 70S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 140 AM EDT TUESDAY...
OVERALL VFR SHOULD PREVAIL THIS MORNING AT THE TAF LOCATIONS. A
FEW SHOWERS MAY MAKE A RUN AT KLWB OVER THE NEXT COUPLE OF HOURS
BUT LIKELY TO DISSIPATE CROSSING THE RIDGES SO LEAVING OUT
MENTION. WELL MIXED LOW LEVELS WILL LIKELY INHIBIT MUCH FOG
DEVELOPMENT THIS MORNING. CANT TOTALLY RULE OUT SOME BRIEF VALLEY
FOG AT KLWB/KBCB ALTHOUGH FORECAST FOG STABILITY VALUES SHOW ONLY
SPOTTY COVERAGE AT BEST.
UPPER TROUGH AND ITS ASSOCIATED COLD FRONT WILL APPROACH FROM THE
NORTHWEST THIS AFTERNOON WITH MOSTLY ISOLATED MOUNTAIN
SHOWERS/STORMS EXPECTED DURING THE DAY AHEAD OF THE BOUNDARY.
HOWEVER MAY SEE A MORE ORGANIZED BAND DROP IN FROM THE NW WITH THE
LEADING PRE- FRONTAL CONVERGENCE...SO INCLUDING A VCTS MENTION
ACROSS THE SOUTHEAST WEST VA SITES AROUND MID AFTERNOON AND LATE
AT KBCB. OTRW EXPECTING MOSTLY VFR AFTER EARLY MID DECK ERODES AND
SCATTERED- BROKEN CU FIELDS BETWEEN 4-6K FT TAKE SHAPE WITH
HEATING. WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
THIS EVENING INTO TONIGHT.
MEDIUM TO HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS
DURING THE PERIOD.
EXTENDED AVIATION DISCUSSION...
FRONT SETTLES CLOSER TUESDAY NIGHT INTO WEDNESDAY...WHEN BETTER
COVERAGE OF SHRA/TSRA IS EXPECTED. HOWEVER LOW CONFIDENCE ON THE
TIMING AND SOUTHWARD POSITION OF THE BOUNDARY ON WEDNESDAY AT THIS
POINT PENDING PRE-FRONTAL COVERAGE FROM TUESDAY NIGHT. FOR NOW APPEARS
MAINLY VFR OUTSIDE OF EARLY MORNING FOG WEDNESDAY...THEN PERIODS
OF MVFR WEDNESDAY AFTERNOON ESPECIALLY SOUTHERN SECTIONS...AND
MAINLY ACROSS THE SOUTH/SOUTHWEST THURSDAY AFTERNOON FOR MORE
ISOLATED NATURE COVERAGE. FRONT WASHES OUT TO THE SOUTH OF THE
AREA FRIDAY WITH MORE WIDELY SCATTERED DIURNAL NATURE SHOWERS AND
STORMS...THEN PERHAPS BECOMING MORE WIDESPREAD SATURDAY WITH
PERIODIC MVFR IN MORE ORGANIZED COVERAGE AHEAD OF ANOTHER COLD
FRONT ARRIVING FROM THE NORTHWEST LATE. OTRW WILL SEE A DAILY
TREND OF EARLY MVFR/IFR IN FOG...FOLLOWED BY BRIEF VFR...THEN
INCREASING AFTERNOON/EVENING CONVECTION WHEN MVFR TO LOCAL IFR
WILL BE POSSIBLE.
&&
.EQUIPMENT...
AS OF 730 AM EDT FRIDAY ...
THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL AIRPORT...WILL
BE OUT OF SERVICE UNTIL FURTHER NOTICE. A PART HAS BEEN BACK-ORDERED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/WP
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...JH/KK
EQUIPMENT...RAB
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
955 PM CDT WED SEP 3 2014
.UPDATE...MCS OVER NW WI NOW WITH A MOTION OF 285 DEGREES AT 39 KTS.
IF THIS MOTION IS MAINTAINED...EAST CENTRAL WI WOULD SEE THE TAIL
END OF THE MCS AFTER 07Z...ALTHOUGH THE MCS HAS THE POTENTIAL TO
TURN MORE RIGHT AND AFFECT MORE OF EAST CENTRAL AND SE WI EARLY THU
AM. ALSO...THE HRRR MODEL CONTINUES TO DEVELOP A NEW AREA OF
CONVECTION OVER WRN WI AROUND 08Z AND BRINGS THAT COMPLEX OF
STORMS ACROSS SRN WI THROUGH THU AM. BELIEVE THIS HAS A GOOD
CHANCE OF OCCURRING AS THE LLJ AND ASSOCIATED WARM...MOIST
ADVECTION VEERS MORE INTO SRN WI. EITHER WAY EXPECT FAIRLY
WIDESPREAD COVERAGE OF TSTORMS DURING THE OVERNIGHT AND LINGERING
INTO THE DAYLIGHT HOURS ON THU. STRONG TO POSSIBLY ISOLD SVR
STORMS ARE EXPECTED AND THIS HAS BEEN HIGHLIGHTED IN THE TOP NEWS
STORY AND THE HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION/06Z TAFS/...FAIRLY WIDESPREAD COVERAGE OF TSTORMS ARE
EXPECTED FROM MADISON TO MILWAUKEE AND SURROUNDING AREAS FROM
08Z-14Z AS A WARM FRONTAL PASSAGE OCCURS. SOME STORMS WILL BE
STRONG WITH GUSTY WINDS AND HAIL. OTHER THAN GREATLY REDUCED CIGS
AND VSBYS WITHIN THE STORMS...THE PREVAILING CONDITIONS WILL BE
MAINLY VFR FOR THU AND THU NT. SOME LOW STRATUS MAY LINGER AFTER
THE TSTORMS THU AM AND AGAIN AFTER ANY STORMS WITH THE APPROACH OF
THE COLD FRONT LATE THU NT-FRI AM.
&&
.PREV DISCUSSION... /ISSUED 336 PM CDT WED SEP 3 2014/
TONIGHT AND THURSDAY...FORECAST CONFIDENCE IS MEDIUM.
IT WILL LIKELY REMAIN DRY THROUGH MUCH OF THE EVENING. SHOWERS
AND STORMS ARE EXPECTED IN THE AREA TONIGHT DUE TO STRONG WARM
ADVECTION ON THE NOSE OF A VIGOROUS LOW LEVEL JET. MESOSCALE
MODELS ARE DEVELOPING A CONVECTIVE COMPLEX ACROSS NORTHWEST
WISCONSIN THIS EVENING...AND THEN DIVE IT SOUTHEASTWARD OVERNIGHT.
THIS SCENARIO MATCHES PRETTY WELL WITH THE CORFIDI VECTORS. BUMPED
POPS UP A BIT AS A RESULT...WITH THE CONSENSUS OF MODELS
SUGGESTING THE BEST CHANCE FOR STORMS WILL BE LATER TONIGHT INTO
THE EARLY MORNING HOURS.
SHOULD SEE THE STORMS WIND DOWN BY MID MORNING THURSDAY...WITH
MODELS SHOWING A VERY WARM AND CAPPED ENVIRONMENT FOR THE
AFTERNOON. IF THE SUN COMES OUT AS EXPECTED...SHOULD SEE HIGHS UP
AROUND 90 MOST PLACES. THESE TEMPS COMBINED WITH DEWPOINTS INTO
THE LOW 70S WOULD RESULT IN HEAT INDEX VALUES IN THE MID TO UPPER
90S...A UNCOMFORTABLE EARLY SEPTEMBER DAY.
SHORT TERM...THURSDAY NIGHT THROUGH SATURDAY...FORECAST
CONFIDENCE IS MEDIUM.
SHORT TERM MODELS ARE IN GOOD AGREEMENT WITH BRINGING COLD FRONT
INTO THE NORTHWEST COUNTIES THURSDAY EVENING...THEN EXITS THE
SOUTHEAST COUNTIES LATER THURSDAY NIGHT. SOUTHWESTERLY 850 MB LOW
LEVEL JET CONTINUES TO FEED MOISTURE INTO THE AREA THURSDAY NIGHT.
NOT SEEING MUCH IN THE WAY OF A 500 MB SHORTWAVE TROUGH
PASSAGE. DO SEE UPPER DIVERGENCE FROM RIGHT REAR QUADRANT OF 250
MB JET STREAK BRUSHING THE AREA.
NAM/GFS FORECAST SOUNDINGS STILL SHOW SOME CONVECTIVE INHIBITION
IN THE LOW LEVELS...WHICH WOULD LIMIT MEAN LAYER PARCELS FROM
REALIZING LARGE AMOUNTS OF MEAN LAYER CAPE. BETTER SHOT WITH LOW
LEVEL JET INITIATING ELEVATED CONVECTION. DEEP LAYER SHEAR IS
MODEST...BEST WINDS ARE AROUND THE 850 MB LEVEL...WITH WEAKER
WINDS ALOFT. THERE CERTAINLY IS SOME UNCERTAINTY HERE WITH HOW
WIDESPREAD ANY CONVECTION WILL BE. LATER TIMING WITH THE FRONT
ALSO IS A NEGATIVE FOR SEVERE POTENTIAL.
SPC HAS NORTHWEST AND NORTH CENTRAL AREAS IN SLIGHT RISK FOR
SEVERE THURSDAY NIGHT...MAINLY FOR DAMAGING WINDS AND SOME LARGE
HAIL. KEPT LIKELY POPS IN THE NORTH THURSDAY EVENING...AND FAR
EAST LATER THURSDAY NIGHT...WITH CHANCE POPS ELSEWHERE.
COLD FRONT SLOWS DOWN AS IT SHIFTS SOUTHEASTWARD FRIDAY INTO
FRIDAY NIGHT...WITH 500 MB VORTICITY MAXIMA MOVING THROUGH THE
AREA FRIDAY AND AGAIN FRIDAY NIGHT. 850 MB TROUGH LINGERS ACROSS
THE AREA FRIDAY AS WELL...WITH SOME MOISTURE LINGERING AT THAT
LEVEL...ESPECIALLY IN THE FAR SOUTHEAST COUNTIES. CONTINUED
LIKELY POPS FOR SHOWERS AND CHANCES FOR STORMS IN THE FAR
SOUTHEAST FRIDAY...WITH LOWER POPS TO THE NORTHWEST. KEPT LOW POPS
FRIDAY NIGHT IN THE FAR SOUTHEAST...UNTIL MOISTURE FINALLY MOVES
OFF TO THE SOUTHEAST.
WARM AND HUMID CONDITIONS WILL CONTINUE THURSDAY NIGHT ACROSS THE
AREA BEFORE THE FRONTAL PASSAGE...LINGERING FRIDAY IN THE FAR
SOUTHEAST WHERE BEST POPS ARE LOCATED.
COLD AIR ADVECTION GRADUALLY TAKES OVER THE AREA FRIDAY INTO
SATURDAY...AS HIGH PRESSURE MOVES EAST FROM THE CENTRAL PLAINS
INTO IOWA. THUS...EXPECT QUIET WEATHER TO TAKE HOLD OF THE AREA BY
FRIDAY NIGHT INTO SATURDAY...WITH TEMPERATURES FALLING A BIT
BELOW SEASONAL NORMALS.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...FORECAST
CONFIDENCE IS MEDIUM.
GFS/ECMWF GRADUALLY SHIFT HIGH PRESSURE EAST ACROSS THE REGION
SATURDAY NIGHT INTO SUNDAY NIGHT AND MONDAY. THIS WILL CONTINUE TO
BRING QUIET WEATHER WITH SLIGHTLY BELOW NORMAL TEMPERATURES
CONTINUING.
GFS/ECMWF CONTINUE TO BE IN BASIC AGREEMENT WITH WARM AIR
ADVECTION RETURNING TO THE REGION MONDAY NIGHT INTO TUESDAY NIGHT
AND WEDNESDAY. THEY DO DIFFER WITH THE TIMING OF THE LOW PRESSURE
SYSTEM MOVING EAST NORTHEAST THROUGH THE REGION TUESDAY INTO
WEDNESDAY...WITH THE GFS QUICKER BY A DAY THAN THE ECMWF. THEY
BOTH HAVE DIFFERENCES WITH THE ASSOCIATED 500 MB SHORTWAVE TROUGH
PASSAGE.
THUS...WILL USE CONSENSUS MODEL POPS AND TEMPERATURES FOR MONDAY
NIGHT INTO WEDNESDAY. TEMPERATURES SHOULD WARM BACK UP TO OR A BIT
ABOVE SEASONAL NORMALS.
AVIATION/00Z TAFS/...
VFR CONDITIONS WILL PREVAIL THROUGH THURSDAY...EXCEPT FOR LOWER
CONDITIONS POSSIBLE IN THUNDERSTORMS. IT SHOULD REMAIN DRY THROUGH
THE EVENING HOURS...WITH STORMS THEN POSSIBLE AFTER MIDNIGHT INTO
EARLY THURSDAY MORNING.
IT SHOULD BE DRY THEN LATER THURSDAY MORNING INTO EARLY
EVENING...WITH MORE STORMS THEN POSSIBLE DURING THE EVENING AND
OVERNIGHT HOURS. STILL THINKING THERE WILL BE SOME LOW LEVEL WIND
SHEAR LATER TONIGHT INTO THURSDAY MORNING...SO WILL KEEP MENTION
IN TAFS.
MARINE...
SOUTHERLY WINDS WILL GUST TO AROUND 20 KNOTS TONIGHT...LIKELY
REMAINING JUST UNDER SMALL CRAFT ADVISORY CONDITIONS. SOUTH TO
SOUTHWEST WINDS THURSDAY WILL THEN LIKELY GUST TO AROUND 25
KNOTS...SO DECIDED TO ISSUE A SMALL CRAFT ADVISORY FROM 15Z
THURSDAY MORNING UNTIL 03Z IN THE EVENING. WAVES WILL INCREASE TO
2 TO 4 FEET TONIGHT AND THEN 3 TO 5 FEET THURSDAY...THE HIGHEST
WAVES IN THE NORTH.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM TO 10 PM CDT THURSDAY FOR
LMZ643>646.
&&
$$
UPDATE...99
TONIGHT/THURSDAY AND AVIATION/MARINE...DDV
THURSDAY NIGHT THROUGH WEDNESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
821 PM CDT WED SEP 3 2014
.MESOSCALE DISCUSSION...
ISSUED AT 821 PM CDT WED SEP 3 2014
SEVERE WEATHER CHANCES ARE ON THE INCREASE FOR TAYLOR AND
POSSIBLY CLARK COUNTIES LATER THIS EVENING. NOCTURNAL INCREASE IN
THE LOW LEVEL JET HAS CAUSED A COUPLE OF STORMS WITHIN THE
CONVECTION TRACKING ACROSS EAST CENTRAL MN AND NORTHWEST WI TO
BECOME SEVERE. WITH 925-850MB MOISTURE TRANSPORT CONTINUING TO
INCREASE THROUGH THE EVENING...AND A PLENTY UNSTABLE 00Z SOUNDING
FROM MPX...ANTICIPATE THESE STORMS SHOULD MAINTAIN SEVERE LIMITS
AS THEY HEAD TOWARDS TAYLOR AND POSSIBLY CLARK COUNTY AS WELL.
ASSUMING A LINEAR MOTION...TAYLOR COUNTY WOULD BE IMPACTED AS
EARLY AS 950 PM. THE SPECIFIC LINE OF STORMS HEADING TOWARDS
TAYLOR ALREADY HAS A REAR INFLOW JET PRESENT...WITH A CWOP SITE
NEAR ALMELUND MN REPORTING A GUST OF 40 KT AT 0101Z. GIVEN THE
SEVERE THUNDERSTORM POTENTIAL...SEVERE THUNDERSTORM WATCH 491 HAS
BEEN ISSUED BY SPC FOR TAYLOR/CLARK COUNTIES.
ADDITIONAL CONVECTIVE DEVELOPMENT REMAINS POSSIBLE OVERNIGHT...
THOUGH RAP/HRRR TRENDS SUGGEST A FEW HOURS LATER...MAYBE TOWARDS
08/09Z. ISOLATED VERY HEAVY RAIN AND MARGINALLY SEVERE HAIL ALSO
REMAIN TO BE THE MAIN HAZARDS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST
TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS
SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS
FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW
POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER
CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A
GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM
ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS
DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND
MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH
MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT
THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT
NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE
MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN
ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS
BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH-
CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL
DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD
POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING
WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN
ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND
PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE
EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR
TRAINING CELLS.
FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW
THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF
STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST
IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES
INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER
AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL
MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE
STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO
ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH
ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT
AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN
THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL
INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY
FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES.
ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE
CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR
FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE
FORECAST TOWARD IT.
ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB
TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP
OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS
CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE
THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL
MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE
LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C
TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K
RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR
WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY
EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN
THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION
CHANCES IN THE 20 TO 50 PERCENT RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A
STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST
AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE
CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS
GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME
QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW
WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM
SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY...
THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN
ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF
LARGE HAIL.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH
THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM
WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR.
FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE
THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY
TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE
TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH
INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY
SEVERE WEATHER AT THIS TIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 654 PM CDT WED SEP 3 2014
A VARIETY OF CONCERNS EXISTS FOR THE TAF SITES OVER THE NEXT 24
HOURS...
1. THUNDERSTORM POTENTIAL. IT APPEARS MUCH OF THE SHOWER AND
THUNDERSTORM ACTIVITY WILL STAY NORTH OF THE TAF SITES FOR THE
EVENING. SHORTLY AFTER MIDNIGHT...THERE ARE INCREASING SIGNS OF
STORMS DEVELOPING OVER LSE...POSSIBLY CLIPPING RST TOO. THESE THEN
PUSH OFF TO THE EAST OVERNIGHT. HAVE FOR NOW KEPT RST DRY...BUT
DID INCLUDE A TEMPO FOR MVFR CONDITIONS AT LSE. HAVE KEPT THE VCTS
GOING...BUT DID NOT INCLUDE THE TS YET AS CONFIDENCE NEEDS TO
INCREASE MORE. HEAVY RAIN AND MARGINALLY SEVERE HAIL APPEAR TO BE
THE MAIN IMPACTS FOR THE TAF SITES. ADDITIONAL STORMS ARE
POSSIBLE VERY LATE IN THE TAF PERIOD AS A COLD FRONT CROSSES...BUT
CONFIDENCE HERE TOO IS TOO LOW TO MENTION IN THE TAF.
2. WINDS. LOOK FOR GUSTS TO DIMINISH SOON WITH LOSS OF DAYTIME
HEATING. HOWEVER...LOW LEVEL WIND SHEAR WILL TAKE ITS PLACE AS
WINDS INCREASE ABOVE THE GROUND. EXPECT THE WIND SHEAR TO END BY
MID MORNING THURSDAY...RESULTING FROM DAYTIME MIXING...WHICH IN
TURN YIELDS MORE GUSTY SOUTHWESTERLY WINDS FOR THURSDAY AFTERNOON.
3. CEILINGS. THERE IS POTENTIAL FOR AN IFR/MVFR STRATUS TO
DEVELOP LATE TONIGHT...ESPECIALLY SHOULD THE TAF SITES BE IMPACTED
BY RAIN. HAVE INCLUDED THIS POTENTIAL WITH A SCATTERED DECK.
SHOULD CONFIDENCE OF THIS STRATUS DECK INCREASE...THE TAFS WILL BE
UPDATED TO INCLUDE A CEILING. ANY STRATUS SHOULD CLIMB TO VFR BY
LATE THURSDAY MORNING THANKS TO SUN WORKING ON IT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
654 PM CDT WED SEP 3 2014
.MESOSCALE DISCUSSION...
ISSUED AT 654 PM CDT WED SEP 3 2014
SHOWERS AND STORMS OVER EAST CENTRAL MN AND NORTHWEST WI CONTINUE
TO SLOWLY PROPAGATE EAST...FUELED BY PERSISTENT 925-850MB
MOISTURE TRANSPORT. THERE DOESNT APPEAR TO BE ANY CONGLOMERATION
OF THE CONVECTION INTO AN MCS...AND WITH THE NOSE OF THE 925-850MB
MOISTURE TRANSPORT CONTINUING TO LIFT NORTH...IT APPEARS THE
STRONGEST OF THIS ACTIVITY SHOULD STAY JUST TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING. TAYLOR COUNTY WOULD APPEAR THE
MOST LIKELY CANDIDATE TO HAVE THE MOST RAINFALL. THIS IS IN GOOD
AGREEMENT WITH THE LAST FEW HRRR RUNS. THE REST OF THE FORECAST
AREA LOOKS TO HAVE MOSTLY A DRY EVENING...WITH TEMPERATURES LIKELY
TAKING AWHILE TO FALL DUE TO A SOUTHERLY BREEZE AND INCREASING
SURFACE DEWPOINTS.
SOMETIME IN THE MIDNIGHT TO 2 AM WINDOW...THE RAP AND HRRR
CONTINUE TO SUGGEST CONVECTION FIRING OVER NORTHEAST IOWA AND THEN
HEADING EAST-NORTHEAST. THIS IS ON THE NOSE OF ANOTHER 925-850MB
MOISTURE TRANSPORT MAXIMA COMING UP THROUGH IOWA...AHEAD OF A WEAK
SHORTWAVE IN EASTERN NEBRASKA...AS WELL AS ON THE EAST SIDE OF
CAPPING. IF THE CONVECTION DOES INDEED FIRE AS THESE MODELS
FORECAST...WHICH THE 03.18Z NAM/NAM-NEST AND 03.12Z HIRES-ARW/NMM
SHOW...ITS LIKELY TO BECOME QUITE NUMEROUS. ON A POSITIVE
NOTE...THE MAXIMA OF MOISTURE TRANSPORT LOOKS TO BE FAIRLY
PROGRESSIVE TO THE EAST- NORTHEAST...SHOVED ALONG BY THE
SHORTWAVE. THIS SHOULD HELP LIMIT QPF AMOUNTS FROM GETTING TOO
CRAZY IN WHAT IS AN OTHERWISE VERY FAVORABLE ENVIRONMENT FOR VERY
HEAVY RAIN. HRRR STORM BASED PROGS SUGGEST HEAVY RAIN AND MAYBE
SOME MARGINALLY SEVERE HAIL AND GUSTY WINDS WOULD BE THE MAIN
HAZARDS WITH MUCH OF THIS ELEVATED CONVECTION. THIS MAKES SENSE
TOO WHEN LOOKING AT FORECAST SOUNDINGS THAT SHOW ONLY ABOUT 20-25
KT OF SHEAR ABOVE 1 KM.
IF OBSERVATIONAL DATA AND MODELS CONTINUE TO TREND TOWARDS THE
HRRR/RAP SCENARIO OVER THE NEXT 2-3 HOURS...WILL CONSIDER BACKING
DOWN ON THE SEVERE WEATHER CHANCES FOR TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST
TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS
SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS
FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW
POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER
CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A
GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM
ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS
DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND
MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH
MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT
THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT
NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE
MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN
ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS
BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH-
CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL
DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD
POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING
WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN
ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND
PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE
EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR
TRAINING CELLS.
FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW
THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF
STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST
IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES
INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER
AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL
MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE
STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO
ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH
ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT
AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN
THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL
INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY
FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES.
ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE
CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR
FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE
FORECAST TOWARD IT.
ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB
TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP
OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS
CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE
THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL
MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE
LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C
TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K
RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR
WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY
EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN
THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION
CHANCES IN THE 20 TO 50 PERCENT RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A
STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST
AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE
CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS
GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME
QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW
WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM
SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY...
THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN
ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF
LARGE HAIL.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH
THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM
WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR.
FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE
THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY
TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE
TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH
INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY
SEVERE WEATHER AT THIS TIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 654 PM CDT WED SEP 3 2014
A VARIETY OF CONCERNS EXISTS FOR THE TAF SITES OVER THE NEXT 24
HOURS...
1. THUNDERSTORM POTENTIAL. IT APPEARS MUCH OF THE SHOWER AND
THUNDERSTORM ACTIVITY WILL STAY NORTH OF THE TAF SITES FOR THE
EVENING. SHORTLY AFTER MIDNIGHT...THERE ARE INCREASING SIGNS OF
STORMS DEVELOPING OVER LSE...POSSIBLY CLIPPING RST TOO. THESE THEN
PUSH OFF TO THE EAST OVERNIGHT. HAVE FOR NOW KEPT RST DRY...BUT
DID INCLUDE A TEMPO FOR MVFR CONDITIONS AT LSE. HAVE KEPT THE VCTS
GOING...BUT DID NOT INCLUDE THE TS YET AS CONFIDENCE NEEDS TO
INCREASE MORE. HEAVY RAIN AND MARGINALLY SEVERE HAIL APPEAR TO BE
THE MAIN IMPACTS FOR THE TAF SITES. ADDITIONAL STORMS ARE
POSSIBLE VERY LATE IN THE TAF PERIOD AS A COLD FRONT CROSSES...BUT
CONFIDENCE HERE TOO IS TOO LOW TO MENTION IN THE TAF.
2. WINDS. LOOK FOR GUSTS TO DIMINISH SOON WITH LOSS OF DAYTIME
HEATING. HOWEVER...LOW LEVEL WIND SHEAR WILL TAKE ITS PLACE AS
WINDS INCREASE ABOVE THE GROUND. EXPECT THE WIND SHEAR TO END BY
MID MORNING THURSDAY...RESULTING FROM DAYTIME MIXING...WHICH IN
TURN YIELDS MORE GUSTY SOUTHWESTERLY WINDS FOR THURSDAY AFTERNOON.
3. CEILINGS. THERE IS POTENTIAL FOR AN IFR/MVFR STRATUS TO
DEVELOP LATE TONIGHT...ESPECIALLY SHOULD THE TAF SITES BE IMPACTED
BY RAIN. HAVE INCLUDED THIS POTENTIAL WITH A SCATTERED DECK.
SHOULD CONFIDENCE OF THIS STRATUS DECK INCREASE...THE TAFS WILL BE
UPDATED TO INCLUDE A CEILING. ANY STRATUS SHOULD CLIMB TO VFR BY
LATE THURSDAY MORNING THANKS TO SUN WORKING ON IT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
436 PM MDT TUE SEP 2 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE
CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE
WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS
AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT
IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND
301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE
LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY
EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT
AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS
QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER
IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN
COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD.
THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF
OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF
THE FCST.
WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY
OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA
WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH
STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY.
MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG
WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH
FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT
INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH
THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND
CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP
SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS
RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD
BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD
FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL
DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP
THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS
DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO
SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS.
.LONG TERM...(FRIDAY THROUGH MONDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A
PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES
WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL
AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE
CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE
SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION
DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL
UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN
THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS
MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND
SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY
LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY
WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT
MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH
DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE
DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF
THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL
MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL
INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY
AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN
DEVELOPS OVER THE ROCKIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1149 AM MDT TUE SEP 2 2014
VFR CONDITIONS WILL PREVAIL AT ALL SITES THROUGH THE PERIOD. GUSTY
SOUTHWEST WINDS WILL BE COMMON TODAY...WITH 20 TO 30 KTS POSSIBLE
FOR WYOMING AND 15 TO 20 KTS AT THE NEBRASKA AIRPORTS. COULD SEE
AN ISOLATED SHOWER NEAR KSNY LATE THIS AFTERNOON AND EVENING...BUT
CONFIDENCE IS LOW THAT THIS WILL MATERIALIZE SO WILL LEAVE IT OUT
OF THE TAF FOR NOW. WINDS WILL EASE THIS EVENING FOR MOST
AREAS...WITH BREEZY CONDITIONS EXPECTED TO LINGER NEAR KCDR
THROUGH THE EARLY OVERNIGHT PERIOD. GUSTY WINDS WILL RETURN ON
WEDNESDAY.
&&
.FIRE WEATHER...
ISSUED AT 420 PM MDT TUE SEP 2 2014
RELATIVE HUMIDITY VALUES HAVE DROPPED TO AROUND 15 PERCENT THIS
AFTERNOON OVER LOWER ELEVATIONS OF SOUTHEAST WYOMING. IN
ADDITION...WEST AND SOUTHWEST WINDS HAVE BEEN GUSTING TO 20-30
MPH. A RED FLAG WARNING REMAINS IN EFFECT THROUGH EARLY THIS
EVENING OVER PORTIONS OF SOUTHEAST WYOMING. TEMPERATURES WILL WARM
ON WEDNESDAY AND WINDS WILL BE MORE BREEZY DURING THE AFTERNOON
DUE TO A STRENGTHENING PRESSURE GRADIENT. THUS...EXPECT CRITICAL
FIRE WEATHER CONDITIONS TO BE MORE WIDESPREAD OVER SOUTHEAST
WYOMING AND FIRE WEATHER WATCHES ARE IN EFFECT. AN ELEVATED FIRE
WEATHER THREAT IS PREDICTED OVER THE WESTERN NEBRASKA PANHANDLE
DUE TO HUMIDITY VALUES FALLING TO 15-20 PERCENT AND WIND GUSTS OF
20-25 MPH DURING THE AFTERNOON. A COLD FRONT ON THURSDAY MORNING
WILL PUSH ACROSS THE AREA WITH MUCH COOLER TEMPERATURES FOR
THURSDAY AND INTO THE WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR WYZ301-302-304-306-309-310.
RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301-302-304-
309.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RJM
AVIATION...RJM
FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
334 AM EDT THU SEP 4 2014
.DISCUSSION...
TODAY-TONIGHT...AXIS OF THE EASTERLY WAVE IS CURRENTLY MOVING
THROUGH THE FLORIDA PENINSULA EARLY THIS MORNING...WITH RUC ANALYSIS
SHOWING THE MAIN VORT MAX ASSOCIATED WITH THE FEATURE STILL BACK
OVER THE NW BAHAMAS. THIS IS COINCIDENT WITH THE LARGER AREA OF
SHOWERS AND STORMS PRESENT OVER THE ATLANTIC EARLY THIS
MORNING...WITH A SLOW INCREASE IN ACTIVITY OVER THE LOCAL WATERS AS
THIS FEATURE ROTATES FURTHER NORTH AND WEST.
WAVE WILL SLOWLY TRANSIT THE PENINSULA DURING THE DAY...PUTTING THE
REGION ON THE MORE FAVORED ASCENDING SIDE OF THE WAVE.
SOUTH-SOUTHEAST FLOW WILL PUSH THE CURRENT DRY SLOT FURTHER NORTH
AND ALLOW MUCH DEEPER MOISTURE TO OVERSPREAD THE AREA.
THOUGH MODELS SHOW BEST DYNAMICS (COOLER TEMPS ALOFT AT VORT MAX)
STAYING MORE OVER THE ATLANTIC...ENOUGH WILL BE IN PLACE FOR POPS IN
THE 50-60 PERCENT RANGE OVER THE REGION THIS AFTERNOON. THERE WILL
PROBABLY BE AN INITIAL FOCUS ALONG THE TREASURE COAST AS ONGOING
ACTIVITY OVER THE ATLANTIC ROTATES CLOSER TO THE PENINSULA...THEN
SHOWERS AND STORMS WILL SHIFT INLAND WITH EAST COAST SEA BREEZE.
MORE SOUTHERLY COMPONENT TO THE FLOW WILL ALLOW BETTER WEST COAST
SEA BREEZE PENETRATION AND MODELS SHOW EVENING COLLISION AROUND LAKE
COUNTY BEFORE SUNSET.
A FEW SHOWERS AND STORMS LINGER INTO EARLY EVENING BEFORE FOCUS
SHIFTS BACK TO ATLANTIC WITH A FEW SHOWERS AND STORMS BRUSHING THE
COAST OVERNIGHT.
FRIDAY...A MID LVL TROUGH WILL MOVE FROM THE CENTRAL FL PENINSULA
TOWARD THE NRN FL PENINSULA THROUGH THE DAY WITH LOW LVL SE FLOW
ACROSS THE AREA. AN AREA OF DEEP MOISTURE CENTERED OVER ORLANDO
COMBINED WITH MID LVL PVA ALONG AND SOUTH OF THE SHEAR AXIS SHOULD
GENERATE SCATTERED TO NUMEROUS SHOWERS AND LIGHTNING STORMS ACROSS
THE INTERIOR WITH 40-50 RAIN CHANCES NEAR THE EAST COAST. WITH
CONSIDERABLE CLOUD COVER IN THE MORNING AND DECENT COVERAGE OF
AFTERNOON SHOWERS AND STORMS HAVE TRIMMED GFS MOS HIGH TEMPS A FEW
DEGREES...INTO THE LOWER 90S INTERIOR TO AROUND 90 AT THE COAST.
COULD BE A FEW STRONG STORMS NEAR METRO ORLANDO AND LAKE COUNTY IN
THE LATE AFTERNOON WITH LOCALLY HEAVY...GUSTY WINDS AND FREQUENT
LIGHTING.
FRIDAY NIGHT...A CHANCE OF STORMS WILL LINGER DURING THE EVENING
ACROSS MAINLY NORTHERN SECTIONS WITH A CHANCE FOR SHOWERS CONTINUING
PAST LATE EVENING. KEPT POPS CLOSE TO MOS WITH LOW TEMPS IN THE
LOWER TO MID 70S.
SATURDAY...A CLOSED 700 MB LOW ACROSS SE GA SHOULD INDUCE LOW
PRESSURE TO DEVELOP TO OUR NORTH ACROSS GA/SC. DEEP MOISTURE WILL
CONTINUE TO TRAIL INTO OUR NRN FORECAST AREA FROM THIS FEATURE WITH
SE/S LOW LVL WINDS AND SW FLOW AT H7. WILL KEEP HIGHEST RAIN CHANCES
FROM 50-60 PCT ACROSS THE INTERIOR AND SLIGHTLY LOWER ALONG THE
COAST WHERE THE EAST COAST SEA BREEZE SHOULD PUSH SLOWLY INLAND WITH
BETTER INLAND PROGRESS ACROSS THE TREASURE COAST. HIGHS UPPER 80S TO
AROUND 90 AT THE COAST AND LOWER 90S OVER THE INTERIOR.
SAT NIGHT/SUNDAY...MID LVL TROUGH CONTINUES ALONG THE SE ATLC COAST
INTO CENTRAL FL WITH GFS INDICATING DEEP MOISTURE LINGERING. THIS
SHOULD ALLOW THE CHANCE FOR STORMS TO CONTINUE INTO SAT EVENING AND
REDEVELOP ON SUNDAY WITH DAYTIME HEATING. WILL SHOW POPS AROUND 50
PCT FOR THE INTERIOR/N COAST AND 40 PCT FROM THE CAPE SOUTH ALONG
THE COAST WHERE THE EAST COAST SEA BREEZE SHOULD PUSH INTO THE
INTERIOR IN THE AFTERNOON. NO RELIEF FROM THE HEAT WITH 90 ALONG THE
COAST AND LOWER 90S FOR THE INTERIOR.
MON-WED...THE TROUGH NEAR THE SE ATLC COAST WILL TRANSITION OFFSHORE
WITH A MORE ZONAL FLOW SETTING UP BY MID WEEK ACROSS THE SOUTH AND
THE MID LVL RIDGE REBUILDING ACROSS CENTRAL FL BY WED. APPEARS THERE
WILL CONTINUE TO BE ADEQUATE MOISTURE FOR SLIGHTLY HIGHER THAN
NORMAL RAIN CHANCES MONDAY...AND THEN WILL TAPER POPS INTO MID WEEK
WITH HIGHER CHANCES ACROSS THE INTERIOR TUE/WED AROUND 40 PCT. HIGHS
90 COAST TO LOWER-MID 90S FOR THE INTERIOR INTO MID WEEK.
&&
.AVIATION...
SCT SHRA/TSRA OVER LCL ATLANTIC THROUGH PERIOD. ISOLD SHRA BRUSHING
ALL COASTAL TERMINALS THROUGH 10Z...EXPECTED TO BECOME SCT-NMRS WITH
ISOLD TSRA 12Z-15Z.
FOCUS FOR CONVECTION WILL SHIFT TO INTERIOR AFTER 15Z WITH SCT-NMRS
SHRA/TSRA AFFECTING INLAND TERMINALS THROUGH 21Z. EVENING SEA BREEZE
COLLISION LIKELY VCNTY KLEE/KISM WHERE ACTIVITY MAY LINGER THROUGH
05/02Z.
&&
.MARINE...
TODAY-TONIGHT...SOUTH-SOUTHEAST FLOW 10-15KTS AS LOCAL ATLANTIC WILL
BE IN BETWEEN EASTERLY WAVE MOVING ACROSS S FL/FL STRAITS AND
WESTERN ATLANTIC RIDGE AXIS OVER THE SE US. PREVAILING SPEEDS MAY BE
CLOSER TO 10KTS DURING THE DAY...BUT WILL SEE AN INCREASE LATER THIS
EVENING AS AREA GETS ON THE BACKSIDE OF WAVE.
SEAS 2FT NEARSHORE AND 2-3FT OFFSHORE. MESSY DOMINANT PERIODS AS
THERE IS ENOUGH OF A SOUTHERLY FLOW COMPONENT THAT QUITE A BIT OF
THE LOCAL WATERS ARE BEING SHADOWED BY THE BAHAMAS. LOCAL BUOYS ARE
CURRENTLY FAVORING 3-5SEC WITH OCCASIONAL 7-8SEC...AND WAVE WATCH
AND SWAN SHOW SIMILAR TREND INTO TONIGHT.
NUMEROUS SHOWERS AND SCATTERED STORMS OVER THE LOCAL WATERS
TODAY...BECOMING SCT INTO TONIGHT.
FRI-MON...SE-S WINDS UP TO 10-15 KNOTS OFFSHORE OVER THE WEEKEND AND
INTO EARLY NEXT WEEK...ESPECIALLY AT NIGHT WHEN A NOCTURNAL INCREASE
IN WINDS IS EXPECTED MOST NIGHT PERIODS THROUGH THE WEEKEND. SEAS
WILL REMAIN 2 FT NEAR SHORE AND 2-3 FT OFFSHORE. HIGHER COVERAGE OF
SHOWERS AND STORMS FRIDAY INTO SATURDAY AND THEN DECREASING ACROSS
THE WATERS SUNDAY INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 75 90 76 / 50 40 50 30
MCO 93 75 92 74 / 50 30 60 30
MLB 90 76 89 76 / 60 40 50 30
VRB 90 74 90 76 / 60 40 50 20
LEE 92 75 92 77 / 60 30 60 30
SFB 93 76 92 77 / 50 30 60 30
ORL 93 77 92 77 / 50 30 60 30
FPR 88 75 90 75 / 60 30 40 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...MOSES
LONG TERM....VOLKMER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
417 AM CDT THU SEP 4 2014
.DISCUSSION...
327 AM CDT
MORNING THUNDERSTORM COVERAGE AND DURATION ALONG WITH IMPACT ON
DAYTIME TEMPERATURES ARE THE SHORT TERM CHALLENGES. THUNDER
CHANCES AND DEGREE OF COOL DOWN ARE THE MAIN LONG TERM POINTS OF
EMPHASIS TODAY.
SHORT TERM...TODAY AND TONIGHT...
AN ACTIVE ELEVATED WARM AND MOIST ADVECTION ZONE SUPPORTING AREAS
OF CONVECTION IS OVER THE REGION EARLY THIS MORNING. A SHORT WAVE
DISTURBANCE IN EASTERN IA AS OF 330 AM HAS BEEN AN INSTIGATOR FOR
MORE ORGANIZED CONVECTION OVER THE DVN CWA. A BROAD BUT STRONG
45KT LOW-LEVEL JET IS ADVECTING IN MOIST AIR AT THE BASE OF
STEEPENING MID-LEVEL LAPSE RATES OF 7-8 C/KM. THIS WILL REMAIN
SUPPORTIVE OF WIDESPREAD CONVECTIVE UPDRAFTS THROUGH 8-9 AM
BEFORE A PROBABLE DIMINISHING TREND AS STORMS APPROACH/MOVE OVER
CHICAGO AND THE I-55 CORRIDOR. A RAP ANALYSIS INDICATES FAIRLY
SHORT CORFIDI PROPAGATION VECTORS WITH NORTHWEST MID-LEVEL FLOW
PERPENDICULAR TO THE LLJ. SO ISOLATED HEAVY RAIN CONCERNS WILL BE
PRESENT AND HAVE BEEN SUPPORTED ON REGIONAL RADAR TRENDS. HAVE
INCREASED QPF IN TANDEM WITH HIGHER POPS THROUGH MID-MORNING.
A STRENGTHENING CAP ALONG WITH THE WEAKENING/EXIT OF THE
AFOREMENTIONED SHORT WAVE SHOULD LIMIT ANY CONVECTIVE CHANCES THIS
AFTERNOON. HOWEVER...SOME CLOUDS MAY LINGER INTO EARLY AFTERNOON.
WITH THAT AND SOME COMMUNITIES SEEING A SLOWER WARMING TREND
EARLY THIS MORNING WITH CLOUDS AND RAIN...HAVE LOWERED
TEMPERATURES IN THE NORTHEAST HALF OF THE FORECAST AREA BY A
COUPLE DEGREES. TEMPERATURES SHOULD STILL REALIZE 90 IN FAR
WESTERN/SOUTHWESTERN AREAS BASED ON 850/925MB TEMPERATURE
CLIMATOLOGY AND SUPPORT FROM PAST SIMILAR EVENTS PER THE CIPS
ANALOGS. HEAT INDEX READINGS IN THIS AREA...FROM BYRON TO GIBSON
CITY AND WESTWARD...WILL LIKELY APPROACH 100 DEGREES DUE TO
FORECAST LOWER 70 DEW POINTS.
A QUIET AND MILD EVENING IS EXPECTED. CONFIDENCE FOR PRECIP
REMAINING OUT OF THE AREA OVERNIGHT IS LOW. WHILE FRONTAL
CONVERGENCE REMAINS OFF TO THE NORTHWEST...QUITE A BIT OF
ELEVATED INSTABILITY WILL BE PRESENT AND OVERALL FORCING FOR
PRECIP IS LOW. BUT AS WE HAVE SEEN EARLY THIS MORNING...EVEN A
SUBTLE WAVE CAN CAUSE PROBLEMS. SO CONTINUE CHANCE POPS.
MTF
LONG TERM FRIDAY THROUGH WEDNESDAY...
THE MAIN FORECAST CONCERNS DURING THE LONG TERM PERIOD FOCUS ON THE
THREAT FOR SHOWERS AND THUNDERSTORMS...SOME POSSIBLY STRONG...AND
THE THREAT OF HEAVY RAINFALL FRIDAY AND FRIDAY NIGHT.
SURFACE LOW PRESSURE CURRENTLY ACROSS THE EASTERN DAKOTAS WILL
SHIFT NORTHEASTWARD TO NEAR JAMES BAY BY THE START OF THE PERIOD
(FRIDAY MORNING). THIS LOW WILL DRIVE A COLD FRONT SOUTHWARD OVER
NORTHERN ILLINOIS BY EARLY FRIDAY AFTERNOON. THE TIMING OF THIS
FRONTAL PASSAGE SHOULD ALLOW THE HEAT AND HUMIDITY TO LINGER...AT
LEAST FOR THE FIRST HALF OF THE DAY...ESPECIALLY ACROSS MY SOUTHERN
AREAS. THEREFORE...HIGHS ON FRIDAY LOOK TO ONCE AGAIN CREEP NEAR THE
90 DEGREE MARK...WITH HEAT INDICIES OF 95 TO 100 SOUTH OF INTERSTATE
80.
THUNDERSTORMS WILL LIKELY FIRE ACROSS FAR NORTHERN ILLINOIS EARLY ON
FRIDAY AS THE FRONT APPROACHES...AND LIKELY INCREASE IN AREAL
COVERAGE BY FRIDAY AFTERNOON. SURFACE BASED STORMS APPEAR
LIKELY...AHEAD OF THE FRONTAL BOUNDARY LATER FRIDAY MORNING AND INTO
THE AFTERNOON...WITH THE PREFRONTAL HIGH THETA-E LOWER LEVEL AIR MASS
EXPECTED TO INDUCE MLCAPES OF 2000-3000 J/KG. ALTHOUGH DEEP LAYER
SHEAR WILL BE SOMEWHAT LACKLUSTER...WITH ONLY AROUND 25 KT OF 0-6 KM
BULK SHEAR...THERE WILL BE A SMALL THREAT FOR MULTI-CELL CLUSTERS
CAPABLE OF PRODUCE STRONG WINDS. HOWEVER...IT APPEAR THE MAIN THREAT
FOR THIS MAY REMAIN SOUTH OF THE CHICAGO AND ROCKFORD AREAS.
THE OTHER THREAT WITH THESE STORMS...AS HAS BEEN THE CASE WITH
STORMS FOR THE LAST FEW WEEKS...IS VERY HEAVY RAINFALL. THE HIGH
THETA E AIR MASS FEATURING PWAT VALUES OF 1.8 TO 2 INCHES WILL LEAD
TO VERY EFFICIENT RAINFALL RATES...AND THIS COUPLED WITH THE FACT
THAT THE STEERING LAYER FLOW LOOKS TO RUN NEARLY PARALLEL TO THE
SURFACE FRONTAL ZONE...TRAINING CELLS ARE A GOOD POSSIBILITY. IT
ALSO APPEARS THAT SHOWERS...POSSIBLY WITH SOME EMBEDDED ELEVATED
THUNDERSTORMS...WILL LIKELY CONTINUE IN THE WAKE OF THE SURFACE
BOUNDARY INTO FRIDAY NIGHT AS AN ANA-LIKE FRONTAL PRECIP EVENT SETS
UP. MID LEVEL FGEN AND THE PROXIMATELY TO THE RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET ALL POINT TO CONTINUED FORCING TO SUPPORT
PRECIP INTO FRIDAY NIGHT.
GIVEN THE POSSIBILITIES OF A PERIOD OF VERY HEAVY RAINFALL...WITH
POSSIBLE TRAINING OF CELLS AHEAD OF THE FRONT...FOLLOWED BY A LONGER
PERIOD OF MODERATE PRECIP INTO FRIDAY NIGHT...HYDRO ISSUES COULD
BECOME A CONCERN.
THINGS QUIET DOWN AND BECOME MUCH COOLER FOR THE WEEKEND UNDER
NORTHERN FLOW. HIGH TEMPERATURES BY SATURDAY AND SUNDAY LOOK TO BE
IN THE LOW TO MID 70S. OVERNIGHT TEMPERATURES INTO SUNDAY MORNING
LOOKS TO BE QUITE CHILLY AS A SURFACE HIGH BUILDS OVERHEAD. THIS
LOOKS TO SET UP WIDESPREAD LOWER 50 DEGREE TEMPERATURES OUTSIDE OF
CHICAGO...WITH EVEN A FEW UPPER 40 DEGREE READINGS POSSIBLE IN THE
WESTERN SUBURBS.
TEMPERATURES LOOK TO MODERATE A BIT BACK INTO THE UPPER 70S INTO
NEXT WEEK. THE NEXT CHANCE FOR STORMS LOOKS TO ENTER THE PICTURE
AGAIN BY LATE MONDAY NIGHT AND TUESDAY AS ANOTHER DISTURBANCE TAKES
AIM ON THE AREA.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LOW-LEVEL WIND SHEAR THROUGH 12Z-13Z.
* SCATTERED TSRA THROUGH MID-MORNING. WITH WIDESPREAD TSRA TO THE
SOUTHWEST/WEST AND NORTH.
* GUSTY SSW WINDS THIS AFTERNOON.
* SMALL CHANCE FOR SHRA/TSRA AGAIN NEAR DAYBREAK FRIDAY.
//DISCUSSION...UPDATED 09Z...
HAVE ADDED A TEMPO TSRA AT ORD. WHILE CONFIDENCE REMAINS LOW IF
TSRA WILL ACTUALLY OCCUR RIGHT AT THE AIRFIELD...THE COVERAGE OF
TSRA CONTINUES TO BE NUMEROUS TO WIDESPREAD TO THE WEST IN A BAND
OF WARM AND MOIST ADVECTION. THIS FORCING WILL POINT TOWARD
CHICAGO AFTER DAYBREAK. IN ADDITION...WIDESPREAD THUNDERSTORM
COVERAGE IS EXPECTED TO THE SOUTHWEST AND POSSIBLY WEST...AS WELL
AS TO THE NORTH /JUST NORTH OF THE WI STATE LINE/ THROUGH 13Z-14Z.
PREV DISCUSSION...UPDATED 06Z...
A POSSIBLY ACTIVE COUPLE/FEW HOURS OF SOME TSRA MAY OCCUR THIS
MORNING AFTER DAYBREAK. FIRST...SOUTHERLY WINDS AT 1500-2500 FT
HAVE BEEN OBSERVED ON DOPPLER RADAR AND AIRCRAFT AT 40-45 KT FROM
MULTIPLE AIRPORTS ACROSS NORTHERN IL AND EASTERN IA. WHILE THERE
IS SURFACE SOUTHERLY FLOW...THE RATE OF INCREASE IN WIND SPEED
WITH HEIGHT APPEARS TO BE QUITE SHARP...SO HAVE ADDED LOW-LEVEL
WIND SHEAR MENTION INTO THE AREA TAFS. OF LARGER CONCERN IS
INCREASING MOISTURE AND INSTABILITY ALOFT BY SUNRISE INTO THE MID-
MORNING HOURS. THIS IS IN TANDEM WITH THE PASSAGE OF AN UPPER
LEVEL DISTURBANCE. THIS SETUP COULD FAVOR EVOLUTION OF
THUNDERSTORMS FROM EASTERN IA AND SOUTHERN WI OVER THE AREA.
CONFIDENCE IS LOW ON EXACTLY WHAT COVERAGE WOULD BE...BUT AT THIS
TIME WOULD BE SURPRISED TO NOT HAVE AT LEAST ISOLATED SHRA/TSRA
OCCURRING IN THE 11Z-16Z WINDOW OVER NORTH CENTRAL/NORTHEAST IL.
ANY ACTIVITY SHOULD SEE A QUICK WEAKENING TREND LATER IN THE
MORNING AND EARLY AFTERNOON AS IT EVOLVES SOUTHEAST.
AGAIN...CONFIDENCE ON THIS IS FAIRLY LOW...BUT WORTH NOTING AT
LEAST VCTS IN TAFS...AND CONTINUE THE TSRA MENTION AT ROCKFORD.
SOUTH-SOUTHWEST SURFACE WINDS SHOULD BECOME GUSTY BY LATE MORNING
OR EARLY AFTERNOON AND PERSIST THROUGH THE AFTERNOON AND POSSIBLY
EVEN EARLY EVE. THE WIND DIRECTION MAY OCCASIONALLY BE NEAR 180
DEGREES. OTHERWISE...THE EVENING INTO THE OVERNIGHT SHOULD BE
FAIRLY QUIET...WITH A SYSTEM COLD FRONT EXPECTED TO ARRIVE AFTER
DAYBREAK FRIDAY...BRINGING SHRA/TSRA CHANCE DURING THE DAY.
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH IN 40-45 KT SSW FLOW AROUND 1500-2500 FT THROUGH DAYBREAK.
* HIGH IN SCATTERED TSRA THROUGH 13Z-15Z. LOW IN WHETHER TSRA WILL
OCCUR OVER THE AIRFIELDS.
* HIGH IN WINDS.
* LOW IN ANY SHRA/TSRA OCCURRING AGAIN LATE THURSDAY NIGHT.
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC TSRA.
SATURDAY THROUGH MONDAY...VFR
TUESDAY...CHC TSRA.
MTF/BMD
&&
.MARINE...
155 AM CDT
THE WEATHER PATTERN ACROSS THE GREAT LAKES REGION WILL BE A BIT
ACTIVE OVER THE NEXT FEW DAYS...WITH SOME PERIODS OF STRONG WINDS IN
THE 25 TO 30 KT RANG...ALONG WITH A PERIOD OR TWO OF SHOWERS AND
STORMS.
A RATHER POTENT EARLY AUTUMN SEASON SURFACE LOW WILL MOVE FROM THE
EASTERN DAKOTAS EARLY THIS MORNING TO NEAR JAMES BAY BY EARLY FRIDAY
MORNING. THIS SYSTEM WILL CONTINUE TO INDUCE SOME STRONG SOUTHERN
WINDS OVER THE LAKE TODAY AND TONIGHT. IT APPEARS THE STRONGEST
WINDS UP TO AROUND 30 KT WILL OCCUR THIS EVENING ACROSS THE NORTHERN
HALF OF THE LAKE...WITH 20 TO 25 KT SOUTHERLY WINDS OVER THE
SOUTHERN HALF OF THE LAKE. THESE STRONG WINDS WILL RESULT IN SMALL
CRAFT ADVISORY CONDITIONS INTO THIS EVENING.
AS THE LOW SHIFTS OVER THE JAMES BAY FRIDAY MORNING...A TRAILING COLD
FRONT WILL SHIFT DOWN THE LAKE DURING THE DAY FRIDAY. WINDS WILL
SHIFT NORTHERLY INTO 15 TO 25 KT RANGE LATER FRIDAY AND INTO
SATURDAY...BEFORE ABATING LATER SATURDAY AS AN AREA OF SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN LAKES REGION. THESE NORTHERLY
WINDS DOWN THE FETCH OF LAKE MICHIGAN MAY AGAIN RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT AND SATURDAY...WITH WAVES
POSSIBLY IN THE 4 TO 7 FT RANGE.
THE WEATHER CONDITIONS LOOK TO QUIET DOWN FOR A COUPLE DAYS FOR
SUNDAY AND INTO EARLY NEXT WEEK AS SURFACE HIGH PRESSURE DOMINATES
ACROSS THE LAKES REGION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM THURSDAY TO 10 PM THURSDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
328 AM CDT THU SEP 4 2014
.DISCUSSION...
327 AM CDT
MORNING THUNDERSTORM COVERAGE AND DURATION ALONG WITH IMPACT ON
DAYTIME TEMPERATURES ARE THE SHORT TERM CHALLENGES. THUNDER
CHANCES AND DEGREE OF COOL DOWN ARE THE MAIN LONG TERM POINTS OF
EMPHASIS TODAY.
SHORT TERM...TODAY AND TONIGHT...
AN ACTIVE ELEVATED WARM AND MOIST ADVECTION ZONE SUPPORTING AREAS
OF CONVECTION IS OVER THE REGION EARLY THIS MORNING. A SHORT WAVE
DISTURBANCE IN EASTERN IA AS OF 330 AM HAS BEEN AN INSTIGATOR FOR
MORE ORGANIZED CONVECTION OVER THE DVN CWA. A BROAD BUT STRONG
45KT LOW-LEVEL JET IS ADVECTING IN MOIST AIR AT THE BASE OF
STEEPENING MID-LEVEL LAPSE RATES OF 7-8 C/KM. THIS WILL REMAIN
SUPPORTIVE OF WIDESPREAD CONVECTIVE UPDRAFTS THROUGH 8-9 AM
BEFORE A PROBABLE DIMINISHING TREND AS STORMS APPROACH/MOVE OVER
CHICAGO AND THE I-55 CORRIDOR. A RAP ANALYSIS INDICATES FAIRLY
SHORT CORFIDI PROPAGATION VECTORS WITH NORTHWEST MID-LEVEL FLOW
PERPENDICULAR TO THE LLJ. SO ISOLATED HEAVY RAIN CONCERNS WILL BE
PRESENT AND HAVE BEEN SUPPORTED ON REGIONAL RADAR TRENDS. HAVE
INCREASED QPF IN TANDEM WITH HIGHER POPS THROUGH MID-MORNING.
A STRENGTHENING CAP ALONG WITH THE WEAKENING/EXIT OF THE
AFOREMENTIONED SHORT WAVE SHOULD LIMIT ANY CONVECTIVE CHANCES THIS
AFTERNOON. HOWEVER...SOME CLOUDS MAY LINGER INTO EARLY AFTERNOON.
WITH THAT AND SOME COMMUNITIES SEEING A SLOWER WARMING TREND
EARLY THIS MORNING WITH CLOUDS AND RAIN...HAVE LOWERED
TEMPERATURES IN THE NORTHEAST HALF OF THE FORECAST AREA BY A
COUPLE DEGREES. TEMPERATURES SHOULD STILL REALIZE 90 IN FAR
WESTERN/SOUTHWESTERN AREAS BASED ON 850/925MB TEMPERATURE
CLIMATOLOGY AND SUPPORT FROM PAST SIMILAR EVENTS PER THE CIPS
ANALOGS. HEAT INDEX READINGS IN THIS AREA...FROM BYRON TO GIBSON
CITY AND WESTWARD...WILL LIKELY APPROACH 100 DEGREES DUE TO
FORECAST LOWER 70 DEW POINTS.
A QUIET AND MILD EVENING IS EXPECTED. CONFIDENCE FOR PRECIP
REMAINING OUT OF THE AREA OVERNIGHT IS LOW. WHILE FRONTAL
CONVERGENCE REMAINS OFF TO THE NORTHWEST...QUITE A BIT OF
ELEVATED INSTABILITY WILL BE PRESENT AND OVERALL FORCING FOR
PRECIP IS LOW. BUT AS WE HAVE SEEN EARLY THIS MORNING...EVEN A
SUBTLE WAVE CAN CAUSE PROBLEMS. SO CONTINUE CHANCE POPS.
MTF
LONG TERM FRIDAY THROUGH WEDNESDAY...
THE MAIN FORECAST CONCERNS DURING THE LONG TERM PERIOD FOCUS ON THE
THREAT FOR SHOWERS AND THUNDERSTORMS...SOME POSSIBLY STRONG...AND
THE THREAT OF HEAVY RAINFALL FRIDAY AND FRIDAY NIGHT.
SURFACE LOW PRESSURE CURRENTLY ACROSS THE EASTERN DAKOTAS WILL
SHIFT NORTHEASTWARD TO NEAR JAMES BAY BY THE START OF THE PERIOD
(FRIDAY MORNING). THIS LOW WILL DRIVE A COLD FRONT SOUTHWARD OVER
NORTHERN ILLINOIS BY EARLY FRIDAY AFTERNOON. THE TIMING OF THIS
FRONTAL PASSAGE SHOULD ALLOW THE HEAT AND HUMIDITY TO LINGER...AT
LEAST FOR THE FIRST HALF OF THE DAY...ESPECIALLY ACROSS MY SOUTHERN
AREAS. THEREFORE...HIGHS ON FRIDAY LOOK TO ONCE AGAIN CREEP NEAR THE
90 DEGREE MARK...WITH HEAT INDICIES OF 95 TO 100 SOUTH OF INTERSTATE
80.
THUNDERSTORMS WILL LIKELY FIRE ACROSS FAR NORTHERN ILLINOIS EARLY ON
FRIDAY AS THE FRONT APPROACHES...AND LIKELY INCREASE IN AREAL
COVERAGE BY FRIDAY AFTERNOON. SURFACE BASED STORMS APPEAR
LIKELY...AHEAD OF THE FRONTAL BOUNDARY LATER FRIDAY MORNING AND INTO
THE AFTERNOON...WITH THE PREFRONTAL HIGH THETA-E LOWER LEVEL AIR MASS
EXPECTED TO INDUCE MLCAPES OF 2000-3000 J/KG. ALTHOUGH DEEP LAYER
SHEAR WILL BE SOMEWHAT LACKLUSTER...WITH ONLY AROUND 25 KT OF 0-6 KM
BULK SHEAR...THERE WILL BE A SMALL THREAT FOR MULTI-CELL CLUSTERS
CAPABLE OF PRODUCE STRONG WINDS. HOWEVER...IT APPEAR THE MAIN THREAT
FOR THIS MAY REMAIN SOUTH OF THE CHICAGO AND ROCKFORD AREAS.
THE OTHER THREAT WITH THESE STORMS...AS HAS BEEN THE CASE WITH
STORMS FOR THE LAST FEW WEEKS...IS VERY HEAVY RAINFALL. THE HIGH
THETA E AIR MASS FEATURING PWAT VALUES OF 1.8 TO 2 INCHES WILL LEAD
TO VERY EFFICIENT RAINFALL RATES...AND THIS COUPLED WITH THE FACT
THAT THE STEERING LAYER FLOW LOOKS TO RUN NEARLY PARALLEL TO THE
SURFACE FRONTAL ZONE...TRAINING CELLS ARE A GOOD POSSIBILITY. IT
ALSO APPEARS THAT SHOWERS...POSSIBLY WITH SOME EMBEDDED ELEVATED
THUNDERSTORMS...WILL LIKELY CONTINUE IN THE WAKE OF THE SURFACE
BOUNDARY INTO FRIDAY NIGHT AS AN ANA-LIKE FRONTAL PRECIP EVENT SETS
UP. MID LEVEL FGEN AND THE PROXIMATELY TO THE RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET ALL POINT TO CONTINUED FORCING TO SUPPORT
PRECIP INTO FRIDAY NIGHT.
GIVEN THE POSSIBILITIES OF A PERIOD OF VERY HEAVY RAINFALL...WITH
POSSIBLE TRAINING OF CELLS AHEAD OF THE FRONT...FOLLOWED BY A LONGER
PERIOD OF MODERATE PRECIP INTO FRIDAY NIGHT...HYDRO ISSUES COULD
BECOME A CONCERN.
THINGS QUIET DOWN AND BECOME MUCH COOLER FOR THE WEEKEND UNDER
NORTHERN FLOW. HIGH TEMPERATURES BY SATURDAY AND SUNDAY LOOK TO BE
IN THE LOW TO MID 70S. OVERNIGHT TEMPERATURES INTO SUNDAY MORNING
LOOKS TO BE QUITE CHILLY AS A SURFACE HIGH BUILDS OVERHEAD. THIS
LOOKS TO SET UP WIDESPREAD LOWER 50 DEGREE TEMPERATURES OUTSIDE OF
CHICAGO...WITH EVEN A FEW UPPER 40 DEGREE READINGS POSSIBLE IN THE
WESTERN SUBURBS.
TEMPERATURES LOOK TO MODERATE A BIT BACK INTO THE UPPER 70S INTO
NEXT WEEK. THE NEXT CHANCE FOR STORMS LOOKS TO ENTER THE PICTURE
AGAIN BY LATE MONDAY NIGHT AND TUESDAY AS ANOTHER DISTURBANCE TAKES
AIM ON THE AREA.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW-LEVEL WIND SHEAR THROUGH 12Z-13Z.
* CHANCE FOR SCATTERED OR AREA OF TSRA THIS MORNING AFTER DAYBREAK.
* GUSTY SSW WINDS THIS AFTERNOON.
* SMALL CHANCE FOR SHRA/TSRA AGAIN NEAR DAYBREAK FRIDAY.
//DISCUSSION...UPDATED 06Z...
A POSSIBLY ACTIVE COUPLE/FEW HOURS OF SOME TSRA MAY OCCUR THIS
MORNING AFTER DAYBREAK. FIRST...SOUTHERLY WINDS AT 1500-2500 FT
HAVE BEEN OBSERVED ON DOPPLER RADAR AND AIRCRAFT AT 40-45 KT FROM
MULTIPLE AIRPORTS ACROSS NORTHERN IL AND EASTERN IA. WHILE THERE
IS SURFACE SOUTHERLY FLOW...THE RATE OF INCREASE IN WIND SPEED
WITH HEIGHT APPEARS TO BE QUITE SHARP...SO HAVE ADDED LOW-LEVEL
WIND SHEAR MENTION INTO THE AREA TAFS. OF LARGER CONCERN IS
INCREASING MOISTURE AND INSTABILITY ALOFT BY SUNRISE INTO THE MID-
MORNING HOURS. THIS IS IN TANDEM WITH THE PASSAGE OF AN UPPER
LEVEL DISTURBANCE. THIS SETUP COULD FAVOR EVOLUTION OF
THUNDERSTORMS FROM EASTERN IA AND SOUTHERN WI OVER THE AREA.
CONFIDENCE IS LOW ON EXACTLY WHAT COVERAGE WOULD BE...BUT AT THIS
TIME WOULD BE SURPRISED TO NOT HAVE AT LEAST ISOLATED SHRA/TSRA
OCCURRING IN THE 11Z-16Z WINDOW OVER NORTH CENTRAL/NORTHEAST IL.
ANY ACTIVITY SHOULD SEE A QUICK WEAKENING TREND LATER IN THE
MORNING AND EARLY AFTERNOON AS IT EVOLVES SOUTHEAST.
AGAIN...CONFIDENCE ON THIS IS FAIRLY LOW...BUT WORTH NOTING AT
LEAST VCTS IN TAFS...AND CONTINUE THE TSRA MENTION AT ROCKFORD.
SOUTH-SOUTHWEST SURFACE WINDS SHOULD BECOME GUSTY BY LATE MORNING
OR EARLY AFTERNOON AND PERSIST THROUGH THE AFTERNOON AND POSSIBLY
EVEN EARLY EVE. THE WIND DIRECTION MAY OCCASIONALLY BE NEAR 180
DEGREES. OTHERWISE...THE EVENING INTO THE OVERNIGHT SHOULD BE
FAIRLY QUIET...WITH A SYSTEM COLD FRONT EXPECTED TO ARRIVE AFTER
DAYBREAK FRIDAY...BRINGING SHRA/TSRA CHANCE DURING THE DAY.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN 40-45 KT SSW FLOW AROUND 1500-2500 FT THROUGH DAYBREAK.
* MEDIUM IN VCTS OCCURRING...LOW IN WHAT COVERAGE OF STORMS WILL
BE AND IF THEY WILL OCCUR OVER THE AIRFIELDS.
* HIGH IN WINDS.
* LOW IN ANY SHRA/TSRA OCCURRING AGAIN LATE THURSDAY NIGHT.
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC TSRA.
SATURDAY THROUGH MONDAY...VFR
TUESDAY...CHC TSRA.
MTF/BMD
&&
.MARINE...
155 AM CDT
THE WEATHER PATTERN ACROSS THE GREAT LAKES REGION WILL BE A BIT
ACTIVE OVER THE NEXT FEW DAYS...WITH SOME PERIODS OF STRONG WINDS IN
THE 25 TO 30 KT RANG...ALONG WITH A PERIOD OR TWO OF SHOWERS AND
STORMS.
A RATHER POTENT EARLY AUTUMN SEASON SURFACE LOW WILL MOVE FROM THE
EASTERN DAKOTAS EARLY THIS MORNING TO NEAR JAMES BAY BY EARLY FRIDAY
MORNING. THIS SYSTEM WILL CONTINUE TO INDUCE SOME STRONG SOUTHERN
WINDS OVER THE LAKE TODAY AND TONIGHT. IT APPEARS THE STRONGEST
WINDS UP TO AROUND 30 KT WILL OCCUR THIS EVENING ACROSS THE NORTHERN
HALF OF THE LAKE...WITH 20 TO 25 KT SOUTHERLY WINDS OVER THE
SOUTHERN HALF OF THE LAKE. THESE STRONG WINDS WILL RESULT IN SMALL
CRAFT ADVISORY CONDITIONS INTO THIS EVENING.
AS THE LOW SHIFTS OVER THE JAMES BAY FRIDAY MORNING...A TRAILING COLD
FRONT WILL SHIFT DOWN THE LAKE DURING THE DAY FRIDAY. WINDS WILL
SHIFT NORTHERLY INTO 15 TO 25 KT RANGE LATER FRIDAY AND INTO
SATURDAY...BEFORE ABATING LATER SATURDAY AS AN AREA OF SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN LAKES REGION. THESE NORTHERLY
WINDS DOWN THE FETCH OF LAKE MICHIGAN MAY AGAIN RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT AND SATURDAY...WITH WAVES
POSSIBLY IN THE 4 TO 7 FT RANGE.
THE WEATHER CONDITIONS LOOK TO QUIET DOWN FOR A COUPLE DAYS FOR
SUNDAY AND INTO EARLY NEXT WEEK AS SURFACE HIGH PRESSURE DOMINATES
ACROSS THE LAKES REGION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM THURSDAY TO 10 PM THURSDAY.
&&
$$
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
156 AM CDT THU SEP 4 2014
.DISCUSSION...
904 PM CDT
ONLY MINOR ADJUSTMENTS TONIGHT. BUT THE GREATEST CHALLENGE RESIDES
WITH PRECIP TIMING...COVERAGE. GUIDANCE MEMBERS DIFFERS ON TIMING
AND PLACEMENT OF CONVECTION/PRECIP OVERNIGHT. THERE IS A WEAK MID-
LVL WAVE SLIDING EAST ACROSS CENTRAL IOWA THAT THE RAP CONTINUES
TO LEAN TOWARDS THE FOCAL POINT OVERNIGHT...WITH DEVELOPMENT
CLOSER TO MIDNIGHT ALONG THE MISS RIVER. THERE HAS BEEN SOME
ISOLATED SHOWERS/THUNDERSTORMS ACROSS SOUTHEAST IOWA SLIDING EAST
INTO IL...HOWEVER THE TRENDS HAS BEEN THAT THIS PRECIP WOULD
WEAKEN. THE NOSE OF THE LLVL JET AND THETA-E IS LIFTING
NORTH...WHICH COUPLED WITH LLVL MOISTURE STEADILY INCREASING WOULD
POINT TOWARDS A POTENTIAL FOR INCREASED PRECIP OVERNIGHT OR CLOSER
TO 8-12Z. WILL NUDGE POPS UP TO ACCOUNT FOR THIS...WITH THE FOCUS
BEING AFT MIDNIGHT AND CLOSER TO DAYBREAK.
BEACHLER
//PREV DISCUSSION...
252 PM CDT
SHORT TERM...
FOR THE REMAINDER OF THIS AFTERNOON AND INTO THIS EVENING...QUIET
WEATHER CONDITIONS WILL PREVAIL AS SFC HIGH PRESSURE MOVES OFF TO
THE EAST AND LOW PRESSURE DEVELOPS OVER THE NORTHERN PLAINS.
ALOFT...BROAD UPPER RIDGING EXTENDS ACROSS THE SRN CONUS WITH ZONAL
FLOW OVER THE NRN CONUS. WINDS ACROSS THE AREA AT THE SFC HAVE BEEN
VERY LIGHT...WHICH HAS ALLOWED A LAKE BREEZE TO FORM...BUT SLIGHTLY
STRONGER WINDS ALOFT HAVE KEPT THE LAKE BREEZE BOUNDARY FROM PUSHING
INLAND MUCH FARTHER THAN DOWNTOWN CHICAGO. SO...WHILE MUCH OF THE
AREA WILL SEE TEMPERATURES TOP OUT IN THE LOWER TO MIDDLE 80S...THE
ILLINOIS LAKEFRONT HAS REMAINED MUCH COOLER WITH HIGHS TODAY TOPPING
OUT IN THE MIDDLE 70S. A FEW WEAK SHORT WAVES ARE RIPPLING THROUGH
THE ZONAL FLOW...GENERATING AREAS OF SHOWERS AND THUNDERSTORMS...BUT
NONE ARE CURRENTLY CLOSE TO THE LOCAL AREA.
INTO THIS EVENING...THERE WILL BE AN INCREASING CHANCE FOR
THUNDERSTORMS AS MOISTURE STREAMS NWD AROUND THE WRN PERIPHERY OF
THE SFC HIGH AS SOUTHERLY FLOW DEVELOPS. BY LATE THIS
EVENING...ANTICIPATE A STRONG CONVECTIVE COMPLEX TO DEVELOP OVER THE
UPPER MISSISSIPPI VALLEY ON THE LEADING EDGE OF A STRONG LOW LEVEL
JET WHERE SPC HAS OUTLOOKED A SLIGHT RISK FOR SEVERE THUNDERSTORMS.
THE MAIN QUESTION REMAINS AS TO HOW THE CONVECTIVE COMPLEX WILL
EVOLVE THROUGH THE EVENING AND OVERNIGHT. THE ANTICIPATION IS THAT
THE SYSTEM MAY DEVELOP INTO A BOWING LINE OR SQUALL LINE OVERNIGHT
AND PROPAGATE TO THE SOUTHEAST...ACROSS WISCONSIN. THE LATEST HIGH
RES MODEL GUIDANCE...INCLUDING THE LOCAL WRF...SUGGEST THAT THE LINE
OF THUNDERSTORMS MAY HANG TOGETHER LONG ENOUGH THE REACH NRN/NWRN IL
AFTER MIDNIGHT AND INTO THE EARLY MORNING HOURS BEFORE DISSIPATING.
HOWEVER...SINCE THERE IS STILL SOME UNCERTAINTY TO THE TIMING AND
TRACK OF THE SYSTEM...HAVE KEPT POPS IN THE CHANCE RANGE AND
CONFINED THE MENTION OF PCPN TO THE NRN TIER COUNTIES OF IL ALONG
THE WISCONSIN BORDER. WHILE THERE IS STILL A CHANCE THAT SOME STRAY
SHOWERS OR THUNDERSTORMS COULD LINGER INTO THE MORNING HOURS
TOMORROW...GENERALLY EXPECT THAT THE REST OF THE DAY THURSDAY SHOULD
BE DRY.
THE MAIN CONCERN FOR THURSDAY WILL BE THE TEMPERATURE FORECAST. THE
UPPER LEVEL PATTERN WILL BEGIN TO SHOW SOME AMPLIFICATION AS THE
UPPER RIDGE BUILDS ACROSS THE MIDWEST AND GREAT LAKES WHILE AN UPPER
LOW MOVING EWD FROM THE PAC NORTHWEST TRACKS ACROSS THE SRN CANADIAN
PRAIRIES. THE MAIN EFFECT FOR THE LOCAL AREA WILL BE A CONTINUATION
OF PUMPING UP LOW LEVEL MOISTURE...WITH SFC DEWPOINT LIKELY CLIMBING
INTO THE LOW 70S. THE VARIOUS AND SUNDRY MODELS ARE IN RELATIVELY
GOOD AGREEMENT ON BRINGING 850MB TEMPS OF 22-23C ACROSS THE AREA.
UNDER FULL SUNSHINE...THIS WOULD IMPLY MAX TEMPS IN THE LOW 90S.
HOWEVER...SOME RESIDUAL CLOUD COVER...EVEN PARTIAL CLOUD
COVER...COULD LIMIT SLIGHTLY THE POTENTIAL MAXIMUM
WARMING...SO...HAVE MAINTAINED THE GOING FORECAST OF MAX TEMPS IN
THE UPPER 80S TO SOME AREAS AROUND 90-91F. THIS COMBINATION OF
TEMPERATURES AROUND 90F WITH DEWPOINTS IN THE LOW 70S WOULD GENERATE
MAX HEAT INDEX VALUES CLOSE TO 100F. SO...WHILE HEAT ADVISORY
CRITERIA WILL LIKELY NOT BE MET...IT WILL CERTAINLY BE A HOT AND
HUMID DAY...THE LIKES OF WHICH HAS BEEN FEW AND FAR BETWEEN THIS
SUMMER.
THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL COME THURSDAY NIGHT AND
FRIDAY AS A SFC LOW DEVELOPS OVER THE CNTRL PLAINS TRACKS NORTHEAST
ACROSS THE UPPER MISSOURI VALLEY AND INTO THE UPPER MISSISSIPPI
VALLEY THURSDAY. THIS SFC LOW WILL DRAG A TRAILING COLD FRONT
ACROSS THE UPPER MISSISSIPPI VALLEY BY THURSDAY EVENING. THE MODEL
GUIDANCE HAS BEEN RELATIVELY CONSISTENT IN ADVERTISING A RELATIVELY
STRONG COLD FRONT ASSOCIATED WITH THE DEEPENING UPPER LEVEL LONGWAVE
TROUGH DROPPING INTO THE NRN PLAINS. THIS IS SHAPING UP TO BE A
RATHER DYNAMIC SYSTEM WITH STRONG UPPER FORCING WITH THE 100KT+ JET
ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES...A STRONG MID
LEVEL TROUGH AND SFC COLD FRONT. ALSO...THE MODELS ARE SHOWING
SIGNIFICANT MOISTURE POOLING AHEAD OF THE SFC FRONT WITH PWATS OF 2
INCHES ALONG THE BOUNDARY. WHILE THE STRONGEST UPPER LEVEL FORCING
WILL BE WELL NORTH OF THE CWA...AS SPC OUTLOOKS A SLIGHT RISK OVER
WISCONSIN AND THE WESTERN GREAT LAKES IN THE DAY 2 OUTLOOK...SO THE
GREATEST SEVERE POTENTIAL SHOULD BE TO THE NORTH...THERE WILL STILL
BE THE POTENTIAL FOR STRONG THUNDERSTORMS PRODUCING LOCALLY HEAVY
RAINFALL. AS THE SYSTEM SHOULD BE QUICKLY PROGRESSIVE...WIDESPREAD
FLOODING SHOULD NOT BE A MAJOR CONCERN...BUT LOCALIZED FLOODING OR
FLASH FLOODING IS A POSSIBILITY IF ANY TRAINING SETS UP AS
INDIVIDUAL CELLS TRACK NEWD WHILE THE LARGER SCALE SYSTEM PROGRESSES
EWD.
FORECAST CONFIDENCE BEGINS TO DIMINISH INTO LATE FRIDAY NIGHT AND
EARLY SATURDAY AND WHEN THE PCPN WILL CLEAR THE CWA. HAVE GENERALLY
BEEN FOLLOWING THE TREND OF THE ECMWF WHICH INDICATES SOME LINGERING
PCPN OVER THE SERN PORTIONS OF THE CWA INTO SATURDAY MORNING WHILE
THE GFS IS A LITTLE SLOW. CURRENTLY FAVOR A FASTER PROGRESSION
GIVEN RELATIVELY LOW AMPLITUDE...FAST FLOW ALOFT...SO...WILL GO DRY
BY SATURDAY AFTERNOON.
FOR THE LONGER TERM...FROM SATURDAY AFTERNOON AND INTO THE MIDDLE OF
NEXT WEEK. EXPECT THAT THE REMAINDER OF THE WEEKEND AND EARLY NEXT
WEEK SHOULD BE DRY...BUT ON THE COOLER SIDE AS HIGH PRESSURE BUILDS
ACROSS THE MIDWEST WHILE A QUICK MOVING LOW SCOOTS ACROSS THE UPPER
GREAT LAKES...SETTING UP LIGHT FLOW OFF OF THE LAKE. BY MONDAY
NIGHT AND INTO TUESDAY...ANOTHER SYSTEM IS EXPECTED TO DEVELOP OVER
THE CNTRL PLAINS...DRAGGING ANOTHER COLD FRONT ACROSS THE
AREA...WHICH WILL BRING CHANCES FOR MORE SHOWERS AND THUNDERSTORMS
BY TUESDAY AND WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW-LEVEL WIND SHEAR THROUGH 12Z-13Z.
* CHANCE FOR SCATTERED OR AREA OF TSRA THIS MORNING AFTER DAYBREAK.
* GUSTY SSW WINDS THIS AFTERNOON.
* SMALL CHANCE FOR SHRA/TSRA AGAIN NEAR DAYBREAK FRIDAY.
//DISCUSSION...UPDATED 06Z...
A POSSIBLY ACTIVE COUPLE/FEW HOURS OF SOME TSRA MAY OCCUR THIS
MORNING AFTER DAYBREAK. FIRST...SOUTHERLY WINDS AT 1500-2500 FT
HAVE BEEN OBSERVED ON DOPPLER RADAR AND AIRCRAFT AT 40-45 KT FROM
MULTIPLE AIRPORTS ACROSS NORTHERN IL AND EASTERN IA. WHILE THERE
IS SURFACE SOUTHERLY FLOW...THE RATE OF INCREASE IN WIND SPEED
WITH HEIGHT APPEARS TO BE QUITE SHARP...SO HAVE ADDED LOW-LEVEL
WIND SHEAR MENTION INTO THE AREA TAFS. OF LARGER CONCERN IS
INCREASING MOISTURE AND INSTABILITY ALOFT BY SUNRISE INTO THE MID-
MORNING HOURS. THIS IS IN TANDEM WITH THE PASSAGE OF AN UPPER
LEVEL DISTURBANCE. THIS SETUP COULD FAVOR EVOLUTION OF
THUNDERSTORMS FROM EASTERN IA AND SOUTHERN WI OVER THE AREA.
CONFIDENCE IS LOW ON EXACTLY WHAT COVERAGE WOULD BE...BUT AT THIS
TIME WOULD BE SURPRISED TO NOT HAVE AT LEAST ISOLATED SHRA/TSRA
OCCURRING IN THE 11Z-16Z WINDOW OVER NORTH CENTRAL/NORTHEAST IL.
ANY ACTIVITY SHOULD SEE A QUICK WEAKENING TREND LATER IN THE
MORNING AND EARLY AFTERNOON AS IT EVOLVES SOUTHEAST.
AGAIN...CONFIDENCE ON THIS IS FAIRLY LOW...BUT WORTH NOTING AT
LEAST VCTS IN TAFS...AND CONTINUE THE TSRA MENTION AT ROCKFORD.
SOUTH-SOUTHWEST SURFACE WINDS SHOULD BECOME GUSTY BY LATE MORNING
OR EARLY AFTERNOON AND PERSIST THROUGH THE AFTERNOON AND POSSIBLY
EVEN EARLY EVE. THE WIND DIRECTION MAY OCCASIONALLY BE NEAR 180
DEGREES. OTHERWISE...THE EVENING INTO THE OVERNIGHT SHOULD BE
FAIRLY QUIET...WITH A SYSTEM COLD FRONT EXPECTED TO ARRIVE AFTER
DAYBREAK FRIDAY...BRINGING SHRA/TSRA CHANCE DURING THE DAY.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN 40-45 KT SSW FLOW AROUND 1500-2500 FT THROUGH DAYBREAK.
* MEDIUM IN VCTS OCCURRING...LOW IN WHAT COVERAGE OF STORMS WILL
BE AND IF THEY WILL OCCUR OVER THE AIRFIELDS.
* HIGH IN WINDS.
* LOW IN ANY SHRA/TSRA OCCURRING AGAIN LATE THURSDAY NIGHT.
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC TSRA.
SATURDAY THROUGH MONDAY...VFR
TUESDAY...CHC TSRA.
MTF/BMD
&&
.MARINE...
155 AM CDT
THE WEATHER PATTERN ACROSS THE GREAT LAKES REGION WILL BE A BIT
ACTIVE OVER THE NEXT FEW DAYS...WITH SOME PERIODS OF STRONG WINDS IN
THE 25 TO 30 KT RANG...ALONG WITH A PERIOD OR TWO OF SHOWERS AND
STORMS.
A RATHER POTENT EARLY AUTUMN SEASON SURFACE LOW WILL MOVE FROM THE
EASTERN DAKOTAS EARLY THIS MORNING TO NEAR JAMES BAY BY EARLY FRIDAY
MORNING. THIS SYSTEM WILL CONTINUE TO INDUCE SOME STRONG SOUTHERN
WINDS OVER THE LAKE TODAY AND TONIGHT. IT APPEARS THE STRONGEST
WINDS UP TO AROUND 30 KT WILL OCCUR THIS EVENING ACROSS THE NORTHERN
HALF OF THE LAKE...WITH 20 TO 25 KT SOUTHERLY WINDS OVER THE
SOUTHERN HALF OF THE LAKE. THESE STRONG WINDS WILL RESULT IN SMALL
CRAFT ADVISORY CONDITIONS INTO THIS EVENING.
AS THE LOW SHIFTS OVER THE JAMES BAY FRIDAY MORNING...A TRAILING COLD
FRONT WILL SHIFT DOWN THE LAKE DURING THE DAY FRIDAY. WINDS WILL
SHIFT NORTHERLY INTO 15 TO 25 KT RANGE LATER FRIDAY AND INTO
SATURDAY...BEFORE ABATING LATER SATURDAY AS AN AREA OF SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN LAKES REGION. THESE NORTHERLY
WINDS DOWN THE FETCH OF LAKE MICHIGAN MAY AGAIN RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT AND SATURDAY...WITH WAVES
POSSIBLY IN THE 4 TO 7 FT RANGE.
THE WEATHER CONDITIONS LOOK TO QUIET DOWN FOR A COUPLE DAYS FOR
SUNDAY AND INTO EARLY NEXT WEEK AS SURFACE HIGH PRESSURE DOMINATES
ACROSS THE LAKES REGION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM THURSDAY TO 10 PM THURSDAY.
&&
$$
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
1234 AM CDT THU SEP 4 2014
.DISCUSSION...
904 PM CDT
ONLY MINOR ADJUSTMENTS TONIGHT. BUT THE GREATEST CHALLENGE RESIDES
WITH PRECIP TIMING...COVERAGE. GUIDANCE MEMBERS DIFFERS ON TIMING
AND PLACEMENT OF CONVECTION/PRECIP OVERNIGHT. THERE IS A WEAK MID-
LVL WAVE SLIDING EAST ACROSS CENTRAL IOWA THAT THE RAP CONTINUES
TO LEAN TOWARDS THE FOCAL POINT OVERNIGHT...WITH DEVELOPMENT
CLOSER TO MIDNIGHT ALONG THE MISS RIVER. THERE HAS BEEN SOME
ISOLATED SHOWERS/THUNDERSTORMS ACROSS SOUTHEAST IOWA SLIDING EAST
INTO IL...HOWEVER THE TRENDS HAS BEEN THAT THIS PRECIP WOULD
WEAKEN. THE NOSE OF THE LLVL JET AND THETA-E IS LIFTING
NORTH...WHICH COUPLED WITH LLVL MOISTURE STEADILY INCREASING WOULD
POINT TOWARDS A POTENTIAL FOR INCREASED PRECIP OVERNIGHT OR CLOSER
TO 8-12Z. WILL NUDGE POPS UP TO ACCOUNT FOR THIS...WITH THE FOCUS
BEING AFT MIDNIGHT AND CLOSER TO DAYBREAK.
BEACHLER
//PREV DISCUSSION...
252 PM CDT
SHORT TERM...
FOR THE REMAINDER OF THIS AFTERNOON AND INTO THIS EVENING...QUIET
WEATHER CONDITIONS WILL PREVAIL AS SFC HIGH PRESSURE MOVES OFF TO
THE EAST AND LOW PRESSURE DEVELOPS OVER THE NORTHERN PLAINS.
ALOFT...BROAD UPPER RIDGING EXTENDS ACROSS THE SRN CONUS WITH ZONAL
FLOW OVER THE NRN CONUS. WINDS ACROSS THE AREA AT THE SFC HAVE BEEN
VERY LIGHT...WHICH HAS ALLOWED A LAKE BREEZE TO FORM...BUT SLIGHTLY
STRONGER WINDS ALOFT HAVE KEPT THE LAKE BREEZE BOUNDARY FROM PUSHING
INLAND MUCH FARTHER THAN DOWNTOWN CHICAGO. SO...WHILE MUCH OF THE
AREA WILL SEE TEMPERATURES TOP OUT IN THE LOWER TO MIDDLE 80S...THE
ILLINOIS LAKEFRONT HAS REMAINED MUCH COOLER WITH HIGHS TODAY TOPPING
OUT IN THE MIDDLE 70S. A FEW WEAK SHORT WAVES ARE RIPPLING THROUGH
THE ZONAL FLOW...GENERATING AREAS OF SHOWERS AND THUNDERSTORMS...BUT
NONE ARE CURRENTLY CLOSE TO THE LOCAL AREA.
INTO THIS EVENING...THERE WILL BE AN INCREASING CHANCE FOR
THUNDERSTORMS AS MOISTURE STREAMS NWD AROUND THE WRN PERIPHERY OF
THE SFC HIGH AS SOUTHERLY FLOW DEVELOPS. BY LATE THIS
EVENING...ANTICIPATE A STRONG CONVECTIVE COMPLEX TO DEVELOP OVER THE
UPPER MISSISSIPPI VALLEY ON THE LEADING EDGE OF A STRONG LOW LEVEL
JET WHERE SPC HAS OUTLOOKED A SLIGHT RISK FOR SEVERE THUNDERSTORMS.
THE MAIN QUESTION REMAINS AS TO HOW THE CONVECTIVE COMPLEX WILL
EVOLVE THROUGH THE EVENING AND OVERNIGHT. THE ANTICIPATION IS THAT
THE SYSTEM MAY DEVELOP INTO A BOWING LINE OR SQUALL LINE OVERNIGHT
AND PROPAGATE TO THE SOUTHEAST...ACROSS WISCONSIN. THE LATEST HIGH
RES MODEL GUIDANCE...INCLUDING THE LOCAL WRF...SUGGEST THAT THE LINE
OF THUNDERSTORMS MAY HANG TOGETHER LONG ENOUGH THE REACH NRN/NWRN IL
AFTER MIDNIGHT AND INTO THE EARLY MORNING HOURS BEFORE DISSIPATING.
HOWEVER...SINCE THERE IS STILL SOME UNCERTAINTY TO THE TIMING AND
TRACK OF THE SYSTEM...HAVE KEPT POPS IN THE CHANCE RANGE AND
CONFINED THE MENTION OF PCPN TO THE NRN TIER COUNTIES OF IL ALONG
THE WISCONSIN BORDER. WHILE THERE IS STILL A CHANCE THAT SOME STRAY
SHOWERS OR THUNDERSTORMS COULD LINGER INTO THE MORNING HOURS
TOMORROW...GENERALLY EXPECT THAT THE REST OF THE DAY THURSDAY SHOULD
BE DRY.
THE MAIN CONCERN FOR THURSDAY WILL BE THE TEMPERATURE FORECAST. THE
UPPER LEVEL PATTERN WILL BEGIN TO SHOW SOME AMPLIFICATION AS THE
UPPER RIDGE BUILDS ACROSS THE MIDWEST AND GREAT LAKES WHILE AN UPPER
LOW MOVING EWD FROM THE PAC NORTHWEST TRACKS ACROSS THE SRN CANADIAN
PRAIRIES. THE MAIN EFFECT FOR THE LOCAL AREA WILL BE A CONTINUATION
OF PUMPING UP LOW LEVEL MOISTURE...WITH SFC DEWPOINT LIKELY CLIMBING
INTO THE LOW 70S. THE VARIOUS AND SUNDRY MODELS ARE IN RELATIVELY
GOOD AGREEMENT ON BRINGING 850MB TEMPS OF 22-23C ACROSS THE AREA.
UNDER FULL SUNSHINE...THIS WOULD IMPLY MAX TEMPS IN THE LOW 90S.
HOWEVER...SOME RESIDUAL CLOUD COVER...EVEN PARTIAL CLOUD
COVER...COULD LIMIT SLIGHTLY THE POTENTIAL MAXIMUM
WARMING...SO...HAVE MAINTAINED THE GOING FORECAST OF MAX TEMPS IN
THE UPPER 80S TO SOME AREAS AROUND 90-91F. THIS COMBINATION OF
TEMPERATURES AROUND 90F WITH DEWPOINTS IN THE LOW 70S WOULD GENERATE
MAX HEAT INDEX VALUES CLOSE TO 100F. SO...WHILE HEAT ADVISORY
CRITERIA WILL LIKELY NOT BE MET...IT WILL CERTAINLY BE A HOT AND
HUMID DAY...THE LIKES OF WHICH HAS BEEN FEW AND FAR BETWEEN THIS
SUMMER.
THE NEXT SIGNIFICANT CHANCE FOR PCPN WILL COME THURSDAY NIGHT AND
FRIDAY AS A SFC LOW DEVELOPS OVER THE CNTRL PLAINS TRACKS NORTHEAST
ACROSS THE UPPER MISSOURI VALLEY AND INTO THE UPPER MISSISSIPPI
VALLEY THURSDAY. THIS SFC LOW WILL DRAG A TRAILING COLD FRONT
ACROSS THE UPPER MISSISSIPPI VALLEY BY THURSDAY EVENING. THE MODEL
GUIDANCE HAS BEEN RELATIVELY CONSISTENT IN ADVERTISING A RELATIVELY
STRONG COLD FRONT ASSOCIATED WITH THE DEEPENING UPPER LEVEL LONGWAVE
TROUGH DROPPING INTO THE NRN PLAINS. THIS IS SHAPING UP TO BE A
RATHER DYNAMIC SYSTEM WITH STRONG UPPER FORCING WITH THE 100KT+ JET
ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES...A STRONG MID
LEVEL TROUGH AND SFC COLD FRONT. ALSO...THE MODELS ARE SHOWING
SIGNIFICANT MOISTURE POOLING AHEAD OF THE SFC FRONT WITH PWATS OF 2
INCHES ALONG THE BOUNDARY. WHILE THE STRONGEST UPPER LEVEL FORCING
WILL BE WELL NORTH OF THE CWA...AS SPC OUTLOOKS A SLIGHT RISK OVER
WISCONSIN AND THE WESTERN GREAT LAKES IN THE DAY 2 OUTLOOK...SO THE
GREATEST SEVERE POTENTIAL SHOULD BE TO THE NORTH...THERE WILL STILL
BE THE POTENTIAL FOR STRONG THUNDERSTORMS PRODUCING LOCALLY HEAVY
RAINFALL. AS THE SYSTEM SHOULD BE QUICKLY PROGRESSIVE...WIDESPREAD
FLOODING SHOULD NOT BE A MAJOR CONCERN...BUT LOCALIZED FLOODING OR
FLASH FLOODING IS A POSSIBILITY IF ANY TRAINING SETS UP AS
INDIVIDUAL CELLS TRACK NEWD WHILE THE LARGER SCALE SYSTEM PROGRESSES
EWD.
FORECAST CONFIDENCE BEGINS TO DIMINISH INTO LATE FRIDAY NIGHT AND
EARLY SATURDAY AND WHEN THE PCPN WILL CLEAR THE CWA. HAVE GENERALLY
BEEN FOLLOWING THE TREND OF THE ECMWF WHICH INDICATES SOME LINGERING
PCPN OVER THE SERN PORTIONS OF THE CWA INTO SATURDAY MORNING WHILE
THE GFS IS A LITTLE SLOW. CURRENTLY FAVOR A FASTER PROGRESSION
GIVEN RELATIVELY LOW AMPLITUDE...FAST FLOW ALOFT...SO...WILL GO DRY
BY SATURDAY AFTERNOON.
FOR THE LONGER TERM...FROM SATURDAY AFTERNOON AND INTO THE MIDDLE OF
NEXT WEEK. EXPECT THAT THE REMAINDER OF THE WEEKEND AND EARLY NEXT
WEEK SHOULD BE DRY...BUT ON THE COOLER SIDE AS HIGH PRESSURE BUILDS
ACROSS THE MIDWEST WHILE A QUICK MOVING LOW SCOOTS ACROSS THE UPPER
GREAT LAKES...SETTING UP LIGHT FLOW OFF OF THE LAKE. BY MONDAY
NIGHT AND INTO TUESDAY...ANOTHER SYSTEM IS EXPECTED TO DEVELOP OVER
THE CNTRL PLAINS...DRAGGING ANOTHER COLD FRONT ACROSS THE
AREA...WHICH WILL BRING CHANCES FOR MORE SHOWERS AND THUNDERSTORMS
BY TUESDAY AND WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW-LEVEL WIND SHEAR THROUGH 12Z-13Z.
* CHANCE FOR SCATTERED OR AREA OF TSRA THIS MORNING AFTER DAYBREAK.
* GUSTY SSW WINDS THIS AFTERNOON.
* SMALL CHANCE FOR SHRA/TSRA AGAIN NEAR DAYBREAK FRIDAY.
//DISCUSSION...UPDATED 06Z...
A POSSIBLY ACTIVE COUPLE/FEW HOURS OF SOME TSRA MAY OCCUR THIS
MORNING AFTER DAYBREAK. FIRST...SOUTHERLY WINDS AT 1500-2500 FT
HAVE BEEN OBSERVED ON DOPPLER RADAR AND AIRCRAFT AT 40-45 KT FROM
MULTIPLE AIRPORTS ACROSS NORTHERN IL AND EASTERN IA. WHILE THERE
IS SURFACE SOUTHERLY FLOW...THE RATE OF INCREASE IN WIND SPEED
WITH HEIGHT APPEARS TO BE QUITE SHARP...SO HAVE ADDED LOW-LEVEL
WIND SHEAR MENTION INTO THE AREA TAFS. OF LARGER CONCERN IS
INCREASING MOISTURE AND INSTABILITY ALOFT BY SUNRISE INTO THE MID-
MORNING HOURS. THIS IS IN TANDEM WITH THE PASSAGE OF AN UPPER
LEVEL DISTURBANCE. THIS SETUP COULD FAVOR EVOLUTION OF
THUNDERSTORMS FROM EASTERN IA AND SOUTHERN WI OVER THE AREA.
CONFIDENCE IS LOW ON EXACTLY WHAT COVERAGE WOULD BE...BUT AT THIS
TIME WOULD BE SURPRISED TO NOT HAVE AT LEAST ISOLATED SHRA/TSRA
OCCURRING IN THE 11Z-16Z WINDOW OVER NORTH CENTRAL/NORTHEAST IL.
ANY ACTIVITY SHOULD SEE A QUICK WEAKENING TREND LATER IN THE
MORNING AND EARLY AFTERNOON AS IT EVOLVES SOUTHEAST.
AGAIN...CONFIDENCE ON THIS IS FAIRLY LOW...BUT WORTH NOTING AT
LEAST VCTS IN TAFS...AND CONTINUE THE TSRA MENTION AT ROCKFORD.
SOUTH-SOUTHWEST SURFACE WINDS SHOULD BECOME GUSTY BY LATE MORNING
OR EARLY AFTERNOON AND PERSIST THROUGH THE AFTERNOON AND POSSIBLY
EVEN EARLY EVE. THE WIND DIRECTION MAY OCCASIONALLY BE NEAR 180
DEGREES. OTHERWISE...THE EVENING INTO THE OVERNIGHT SHOULD BE
FAIRLY QUIET...WITH A SYSTEM COLD FRONT EXPECTED TO ARRIVE AFTER
DAYBREAK FRIDAY...BRINGING SHRA/TSRA CHANCE DURING THE DAY.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN 40-45 KT SSW FLOW AROUND 1500-2500 FT THROUGH DAYBREAK.
* MEDIUM IN VCTS OCCURRING...LOW IN WHAT COVERAGE OF STORMS WILL
BE AND IF THEY WILL OCCUR OVER THE AIRFIELDS.
* HIGH IN WINDS.
* LOW IN ANY SHRA/TSRA OCCURRING AGAIN LATE THURSDAY NIGHT.
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC TSRA.
SATURDAY THROUGH MONDAY...VFR
TUESDAY...CHC TSRA.
MTF/BMD
&&
.MARINE...
218 PM CDT
STRONG SOUTH TO SOUTHWEST WINDS THURSDAY AND THURSDAY NIGHT WILL BE
THE MAIN FOCUS OF THE FORECAST. CURRENTLY...HIGH PRESSURE IS
STRETCHED ACROSS THE APPALACHIANS WITH A WEAKER RIDGE AXIS ACROSS
LAKE MICHIGAN. LOW PRESSURE IS SPREAD ACROSS THE NORTHERN PLAINS AND
WILL CONSOLIDATE AS IT LIFTS NORTHEAST ACROSS NORTHERN MINNESOTA AND
INTO WESTERN ONTARIO INTO FRIDAY. THIS WILL BRING A STRENGTHENING
PRESSURE GRADIENT ACROSS LAKE MICHIGAN STARTING TONIGHT WHICH WILL
BRING AN INCREASING SOUTH WIND. THE STRONGEST WINDS ARE EXPECTED
THURSDAY EVENING/NIGHT AS THE LOW DEEPENS AS IT TRACKS EASTWARD
ACROSS NORTH CENTRAL ONTARIO. FORTUNATELY WARM AIR WILL BE IN PLACE
ACROSS THE LAKE WHICH WILL LIMIT MIXING AND WILL LIKELY KEEP WIND
SPEEDS BELOW GALE FORCE. THE STRONGEST WINDS WILL BE ACROSS CENTRAL
AND NORTHERN LAKE MICHIGAN WITH SPEEDS TO 30 KT EXPECTED. WINDS WILL
STRENGTHEN QUICKLY IN THE FIRST FEW HUNDRED FEET ABOVE THE LAKE
SURFACE SO SOME OF THE TALLEST PILOT HOUSES MAY SEE 35-40 KT WINDS
WHILE WINDS CLOSER TO THE SURFACE REMAIN NEAR 30 KT. A COOL FRONT
WILL CROSS THE LAKE FRIDAY MORNING TURNING WINDS NORTHERLY BUT THE
GRADIENT WILL QUICKLY SLACKEN ALLOWING SPEEDS TO DIMINISH. WITH
SOUTH TO SOUTHWEST WINDS BLOWING OFFSHORE ACROSS THE IL/IN NEARSHORE
WATERS THURSDAY/THURSDAY NIGHT BETTER MIXING WILL OCCUR OVER THE
NEARSHORE WATERS. EXPECT GUSTS TO AROUND 25 KT THURSDAY AFTERNOON
WITH PEAK MIXING BUT THEN EASE AFTER DARK THURSDAY EVENING. WILL
HOIST A SMALL CRAFT ADVISORY FROM LATE THURSDAY MORNING THROUGH THE
EARLY EVENING. HIGH PRESSURE WILL SETTLE SOUTHWARD INTO THE CENTRAL
PLAINS KEEPING A DECENT PRESSURE GRADIENT ACROSS SOUTHERN LAKE
MICHIGAN FRIDAY AFTERNOON THROUGH SATURDAY. SPEEDS REMAIN JUST
BELOW SMALL CRAFT CRITERIA BUT THE SUSTAINED PERIOD OF LONGER FETCH
MAY BRING WAVES TO SMALL CRAFT CRITERIA LATE FRIDAY NIGHT THROUGH
THE DAY SATURDAY.
HIGH PRESSURE RIDGE WILL SPREAD ACROSS THE ENTIRE LAKE LATER
SATURDAY ALLOWING WINDS TO DIMINISH INTO SATURDAY NIGHT. THE HIGH
WILL GRADUALLY WORK EASTWARD THROUGH MONDAY KEEPING WINDS LIGHT
OVERALL WITH A TENDENCY TO TURN ONSHORE SUNDAY AND MONDAY AFTERNOON.
A STEADIER SOUTHERLY WIND IS EXPECTED TO RETURN INTO TUESDAY.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM THURSDAY TO 10 PM THURSDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
412 AM EDT THU SEP 4 2014
.SYNOPSIS...
ISSUED AT 403 AM EDT THU SEP 4 2014
A WARM FRONT WILL MOVE NORTH TODAY AND BRING A SMALL CHANCE FOR
SHOWERS AND THUNDERSTORMS TO NORTHERN INDIANA AND SOUTHWEST LOWER
MICHIGAN THROUGH EARLY AFTERNOON. SKIES WILL BE PARTLY TO MOSTLY
CLOUDY THIS MORNING FOLLOWED BY CLEARING THIS AFTERNOON. IT WILL
BECOME MORE HUMID AND WARMER BY THIS AFTERNOON WITH HIGHS
REACHING THE MIDDLE TO UPPER 80S. THERE WILL BE A SLIGHT CHANCE
FOR A THUNDERSTORM TONIGHT...MAINLY AFTER MIDNIGHT AND NORTH OF
HIGHWAY 30. IT WILL REMAIN VERY MUGGY AND WARM OVERNIGHT WITH LOWS
IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EDT THU SEP 4 2014
IMMEDIATE CONCERN IN THE SHORT TERM PERIOD IS HANDLING OF UPSTREAM
CONVECTION THAT HAS FIRED OVERNIGHT. LOW LEVEL JET NOSING INTO
THETA E GRADIENT HAS ALLOWED CONVECTION TO DEVELOP OVER IA AND IT
CONTINUES TO RIDE NOSE OF THIS LLJ AND TRACK EAST. WEAK CONVECTION
HAS TRIED TO FIRE AHEAD OF THIS AREA OVER EASTERN IL AND SOUTHERN
LAKE MICHIGAN BUT IT HAS STRUGGLED SO FAR WITH DRIER AIR STILL IN
PLACE. AS THETA E RIDGE SHIFTS EAST EARLY THIS MORNING EXPECT
CONVECTIVE COMPLEX TO CONTINUE ITS TREK EAST AS WELL. AS DAYTIME
HEATING COMMENCES AND LLJ RELAXES EXPECT THIS CONVECTION TO
DISSIPATE THROUGH THE MORNING HOURS. HIRES MODELS HAVE BEEN TRYING
TO HANDLE THIS ALONG WITH LARGER COMPLEX FURTHER NORTH BUT HAVE
BEEN STRUGGLING WITH EVOLUTION DETAILS. LATEST RUC AND HRRR HAVE
PICKED UP ON IA COMPLEX BUT SEEM UNDERDONE AND HAVE THIS
DISSIPATING BEFORE REACHING THE AREA. EXPECT NEXT FEW RUNS TO BE
MORE AGGRESSIVE BASED ON LATEST RADAR/SATELLITE/LIGHTNING TRENDS.
30 TO 40 KNOT LLJ FEEDING THIS SEEMS TO BE KEEPING IT ON AN
EASTWARD TRACK DESPITE 850-300MB THICKNESS LINES SHOWING A
POSSIBLE MOVEMENT TO THE SOUTHEAST. WILL HAVE TO MONITOR TRENDS
NEXT FEW HOURS CLOSELY BUT FOR NOW HAVE EXPANDED POPS AND
INCREASED SKY COVER THIS MORNING TO COVER MOST OF WESTERN AND
NORTHERN THIRD OF CWA. WILL TAPER POPS OFF BY AFTERNOON WITH SKIES
BECOMING PARTLY CLOUDY TO MOSTLY SUNNY. THIS POSES THE NEXT
PROBLEM WITH HIGH TEMPS FOR TODAY. SOUNDINGS SUGGEST MIXING TO
AROUND 900MB WHICH WILL YIELD HIGHS IN THE MID TO UPPER 80S.
OBVIOUSLY NOW LOOKING AT SLOWER WARMING TRENDS THIS MORNING WITH
SATELLITE SHOWING INCREASED CLOUD DEVELOPMENT. STILL EXPECT A
RAPID WARMUP LATER IN THE DAY ONCE CLOUDS ERODE SO STAYED WITH MID
80S EXCEPT IN FAR SOUTHWEST WHERE UPPER 80S STILL LIKELY.
MODEL SOUNDINGS SHOW DECENT CAPPING INVERSION THIS AFTERNOON DESPITE
MUCAPES CLIMBING TO BETWEEN 1K AND 2K J/KG. DEWPOINTS WILL CREEP
INTO THE UPPER 60S MAKING IT FEEL QUITE HUMID. NOT MUCH FOCUS FOR
CONVECTION TONIGHT BUT MOISTURE RICH AIR WILL BE IN PLACE WITH
ELEVATED INSTABILITY SO IT WILL NOT TAKE MUCH TO SPARK AN ISOLATED
TSRA. WILL KEEP SLIGHT CHANCE POPS ACROSS NORTHERN TWO THIRDS OF
AREA WELL AHEAD OF MAIN COLD FRONT.
&&
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 403 AM EDT THU SEP 4 2014
MAIN FOCUS FRIDAY-FRIDAY NIGHT REMAINS CONVECTIVE CHANCES/COVERAGE
AS TRAILING COLD FRONT FROM POTENT SHORTWAVE TRACKING NE TO JAMES
BAY SAGS SOUTHEAST INTO A MOIST/UNSTABLE AIRMASS. MUCH OF FRIDAY
MORNING-EARLY AFTERNOON SHOULD REMAIN MAINLY DRY IN CAPPED WARM
SECTOR (850 MB TEMPS 21C)...ALTHOUGH CANNOT COMPLETELY RULE OUT
CONVECTIVE REMNANTS/OUTFLOW SURVIVING INTO NORTHERN/WESTERN ZONES IN
LOW LEVEL THETA-E ADVECTION REGIME. EXPECTED STRONG DIURNAL HEATING
AND POOLED 70F DEWPOINTS NEAR FRONT...CONCURRENT WITH OVERSPREAD OF
WEAK 20-30M 5H HEIGHT FALLS...SHOULD BE SUFFICIENT TO BREAK CAP/FIRE
CONVECTION ALONG THE SAGGING FRONTAL ZONE BY MID-LATE AFTERNOON.
COVERAGE REMAINS QUESTIONABLE HOWEVER WITH BETTER MID LEVEL HEIGHT
FALLS/FORCING INITIALLY CONFINED NORTH. THIS REMAINS THE PRIMARY
REASON FOR HOLDING SHY OF LIKELY POPS AT THIS FCST RANGE. POST
FRONTAL LAG OF STRONGER MID LEVEL FLOW/DEEP SHEAR AND WHAT SHOULD BE
A VERY UNSTABLE ENVIRONMENT (MLCAPE 2500 J/KG PLUS) HINTS AT A LOW
END SEVERE THREAT (ISOLATED) WITH SHORT-LIVED UPDRAFTS CAPABLE OF
PRODUCING STRONG OUTFLOWS/DOWNBURSTS. FAIR AMOUNT OF CAPE IN THE
M10-M30 LAYER ALSO SUGGESTIVE OF A LOW END HAIL THREAT AS WELL.
OVERSPREAD OF BETTER HEIGHT FALLS/RIGHT ENTRANCE UPPER JET SUPPORT
WILL TIGHTEN/DEEPEN THE FRONTAL ZONE AS IT DROPS THROUGH
SOUTHERN/EASTERN ZONES FRIDAY NIGHT...WITH AMPLE MOISTURE AND
POTENTIAL FOR LOWER AMPLITUDE SHORTWAVE ENERGY TO PROPAGATE THROUGH
IN SW FLOW PROBABLY ENOUGH TO HELP GENERATE ADDITIONAL RAIN/THUNDER
ALONG FRONTAL SLOPE. WITH THAT SAID...ONCE AGAIN HELD SHY OF LIKELY
POPS GIVEN NORMAL UNCERTAINTIES WITH CONVECTION AND RECENT MAINLY
DRY FRONTAL PASSAGES IN SIMILAR SETUPS.
A FEW SHOWERS/LOW CLOUDS MAY LINGER INTO SATURDAY MORNING ACROSS
SOUTHERN/EASTERN ZONES...WITH THE REST OF THE WEEKEND INTO EARLY
NEXT WEEK MUCH COOLER/DRIER AS BROAD HIGH PRESSURE BUILDS IN WAKE OF
FRONT/SHORTWAVE TROUGH. RETURN FLOW TIMED WITH THE NEXT ROUND OF
HEIGHT FALLS ON THE BACKSIDE OF THIS AREA OF HIGH PRESSURE BRINGS
SHOWER/STORM CHANCES BACK INTO THE FORECAST BY THE MIDDLE OF NEXT
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 133 AM EDT THU SEP 4 2014
VFR CONDITIONS TO START THE PERIOD AND FOR THE MOST PART EXPECT
VFR THROUGH THIS TAF PERIOD. EXCEPTION WILL BE POSSIBLE MVFR BR
TOWARD DAYBREAK AT KFWA WITH LIGHT WINDS AND RESIDUAL LOW LEVEL
MOISTURE. SATELLITE AND RADAR SHOWS TWO CONVECTIVE SYSTEMS WHICH
HAVE DEVELOPED UPSTREAM...ONE ACROSS CENTRAL AND NORTHERN WI AND
A SMALLER AREA OVER EASTERN IA. HIRES SHORT TERM GUIDANCE HAS SOME
IDEA OF THESE AREAS BUT DETAILS NOT HANDLED WELL. WILL HAVE TO
MONITOR BUT POINT PROBABILITIES TOO SMALL FOR ANY MENTION IN TAFS
AT THIS TIME. ATMOSPHERE BECOMES MARGINALLY UNSTABLE TODAY WITH
HEATING BUT NO TRIGGER MECHANISM AND DECENT CAPPING INVERSION
SHOULD KEEP CONVECTION FROM FORMING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...STEINWEDEL
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
331 AM CDT THU SEP 4 2014
.SYNOPSIS...
ISSUED AT 304 AM CDT THU SEP 4 2014
COLD FRONT FROM EASTERN SD INTO CO WILL MOVE SOUTHEAST ACROSS THE
STATE BY FRIDAY MORNING. A WAVE WILL MOVE NORTHEAST ALONG THE
FRONT ON FRIDAY...PASSING SOUTH OF IA DURING THE DAY. HIGH
PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND. NEXT FRONTAL
SYSTEM SLATED TO MOVE THROUGH THE AREA ABOUT TUESDAY.
&&
.SHORT TERM /TODAY/...
ISSUED AT 304 AM CDT THU SEP 4 2014
MAIN FORECAST CONCERN WAS ANOTHER HOT AND HUMID DAY AND
WITH POTENTIAL FOR CONVECTION LATE THIS AFTERNOON. LEANED TOWARD THE
SLIGHTLY WARMER ECMWF/GFS FOR HIGHS TODAY AS THERE SHOULD BE SOME
DECENT MIXING TO AROUND 900MB AND WAA THROUGHOUT THE DAY. THE WAA
HAS KEPT TEMPS UP OVERNIGHT IN THE MID TO UPPER 70S. A SHARP COLD
FRONT IS SLATED TO PUSH INTO NORTHWEST LATE THIS AFTERNOON INTO THE
EVENING AND CAP LOOKS TO HOLD THROUGH MUCH OF THE DAY. THE HIRES
MODELS (NMM/ARW) BREAK OUT SOME ISOLATED STORMS BY 19-20Z TODAY.
HOWEVER...THE 04.00Z HOPWRF/04.05Z HRRR KEYING IN ON A VERY WEAK
SHORTWAVE OVER SOUTHERN NEBRASKA AND HAS STORMS DEVELOPING BY AROUND
16-17Z. HOWEVER...BELIEVE THE STRONG CAP IN PLACE WILL HOLD UNTIL
THE COLD FRONT LATER THIS AFTERNOON ENTERS THE STATE. ONE THING TO
NOTE...IF WEAK ISOLATED CONVECTION THAT THE HOPWRF/HRRR DOES
DEVELOP...WILL HINDER MAX TEMPS A LITTLE TODAY OVER THE SOUTH. AT
ANY RATE...HAVE POPS INCREASING PAST 20Z OVER THE WEST TO NORTHWEST
AS THE COLD FRONT BEGINS TO SAG SOUTHEAST INTO THE STATE.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 304 AM CDT THU SEP 4 2014
THUNDERSTORMS ARE LIKELY TO DEVELOP ALONG AND JUST BEHIND THE COLD
FRONT DAY AS IT SLIDES SOUTHEAST AIRMASS IS QUITE CAPPED
INITIALLY...BUT COLD AIR ALOFT WILL ALLOW THE CAP TO BREAK AND
EXPECT A LINE OF THUNDERSTORMS TO DEVELOP AND MOVE TROUGH THE
STATE. RAIN WILL CONTINUE OVER THE SOUTH AND EAST ON FRIDAY AS A
S/WV RESULTS IN A WAVE LIFTING NORTHEAST ALONG THE FRONT FRIDAY.
HIGH PRESSURE WILL PUSH IN AND DOMINATE THE WEATHER OVER THE
WEEKEND WITH COOLER AND DRIER AIR IN PLACE. THE NEXT FRONTAL
SYSTEM WILL BE WEAKER...BUT WILL BRING A CHANCE FOR RAIN IN THE
MONDAY TUESDAY TIMEFRAME. DO NOT EXPECT TO SEE THE WARMING WITH
THE NEXT SYSTEM THAT IS OCCURRING BEFORE THE CURRENT COLD FRONT.
FURTHER AHEAD...A STRONGER FRONT WILL BRING A CHANCE FOR RAIN
ABOUT THURSDAY. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
LATER NEXT WEEK WITH THE A COOL PUSH OF FALL AIR OVER THE UPPER
MIDWEST. THE MODELS HAVE BECOME MORE CONSISTENT WITH THIS BOTH IN
MODEL TO MODEL AND RUN TO RUN CONTINUITY.
&&
.AVIATION...04/06Z
ISSUED AT 1157 PM CDT WED SEP 3 2014
SOUTHERLY WINDS EXPECTED TO CONTINUE WITH VFR CONDITIONS THROUGH
THE TAF PERIOD. A COLD FRONT WILL SWEEP ACROSS THE STATE LATE
THURSDAY EVENING INTO THE OVERNIGHT HOURS. BROUGHT IN SOME LOW VFR
CIGS TOWARD THE END OF THE FORECAST PERIOD AS THE FRONT NEARS THE
TAF SITES...AND SOME VCTS ACROSS THE NORTHERN TAF SITES WITH
THUNDERSTORM ACTIVITY EXPECTED ALONG AND NEAR THE FRONTAL
BOUNDARY. WINDS WILL SHIFT AROUND TO THE NORTHWEST BEHIND THE
FRONT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MS SEP 14
SHORT TERM...PODRAZIK
LONG TERM...MS SEP 14
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1101 PM MDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 150 PM MDT WED SEP 3 2014
WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN
SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT
MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON
MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE
POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE
THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS
SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY
THAN FURTHER NORTH.
AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY
OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE
INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO
OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN
INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS
EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL
MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT
OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE
SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER
TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT
IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW
ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST
AFTER THE SHORT TERM PERIOD.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 242 PM MDT WED SEP 3 2014
THURSDAY NIGHT AND FRIDAY WIDESPREAD RAINFALL...HEAVY AT TIMES...LOOKS
VERY LIKELY FOR THE AREA.
THURSDAY NIGHT MID AND UPPER LEVEL MIXING RATIOS INCREASE AHEAD OF A
COMPACT UPPER LEVEL SHORT WAVE TROUGH THAT WILL MOVE ACROSS THE AREA
THROUGH THE NIGHT. AHEAD OF THE TROUGH ELEVATED CAPE DEVELOPS AS
THE JET AT 750MB NOSES IN THE FROM THE SOUTHEAST...AND PROGRESSES
NORTHWEST ACROSS MOST OF THE AREA THROUGH THE NIGHT. WITH
ISENTROPIC AS WELL AS SYNOPTIC LIFT OCCURRING ALONG THE NOSE OF THIS
JET...ANTICIPATE ELEVATED STORMS TO DEVELOP ALONG IT BY EARLY
EVENING. ELEVATED CAPE ABOVE 750MB MAY BE AS HIGH AS 2500J/KG ALONG
AND SOUTHEAST OF THE NOSE OF THE 750MB JET...WITH INSTABILITY
DECREASING DRAMATICALLY NORTHWEST OF THE NOSE. IF STORMS ARE ABLE
TO TAP INTO THE HIGHER INSTABILITY HAIL UP TO 2 INCHES IN DIAMETER
WILL BE POSSIBLE DUE TO DEEP LAYER SHEAR OF 35KTS. HOWEVER FURTHER
NORTHWEST OF THE JET NOSE HAIL SIZE WILL TAPPER OFF DRAMATICALLY DUE
TO LITTLE TO NO ELEVATED CAPE. PLACED SEVERE WORDING IN THE
FORECAST WHERE SEVERE STORMS WILL BE MOST LIKELY. IN ADDITION TO
THE LARGE HAIL...MEAN STORM MOTION WILL BE AROUND 20MPH AND WILL BE
PARALLEL TO THE NOSE OF THE 750MB JET. THIS WILL LEAD TO SLOW
MOVING TRAINING STORMS CAPABLE OF PRODUCING HEAVY RAINFALL.
ANTICIPATE STORMS TO START OFF AS MORE SUPER CELLULAR IN THE EVENING
WHEN ELEVATED CAPE IS HIGHEST. OVERNIGHT AS THE ELEVATED
INSTABILITY DIMINISHES AND ICE NUCLEI SEEDING FROM UPWIND STORMS
OCCURS...BELIEVE THE HAIL SIZE WILL BECOME SMALLER THAN ONE INCH IN
DIAMETER. HOWEVER HEAVY RAINFALL WILL BECOME MORE OF A THREAT.
FURTHER NORTHWEST OF THE NOSE OF THE 750MB JET 700-500MB THETA-E
LAPSE RATES INDICATE A CONVECTIVELY UNSTABLE ENVIRONMENT DESPITE THE
LACK OF ELEVATED CAPE. WITH UPPER LEVEL SHORT WAVE TROUGH MOVING
ACROSS MOST OF THE AREA THROUGH THE NIGHT DECIDED TO KEEP THE
RAINFALL CHANCES GOING FOR THE REST OF THE AREA...WITH THE BEST
CHANCE FOR RAINFALL ACTUALLY SHIFTING NORTH TOWARD THE NE BORDER
OVERNIGHT FOLLOWING THE HIGHER 700-500MB MIXING RATIOS AND 700-500MB
FRONTOGENESIS.
ASIDE FROM THE WIDESPREAD RAINFALL...A SECOND SURGE OF COOLER AIR
WILL MOVE INTO THE AREA FROM THE NORTH THROUGH THE NIGHT.
FRIDAY MORNING THE UPPER LEVEL SHORT WAVE TROUGH FROM LAST NIGHT
WILL EXIT THE AREA AS ANOTHER SHORT WAVE TROUGH DEEPENS OVER THE
WESTERN PART OF THE AREA. MEANWHILE THE BAND OF 700-500MB
FRONTOGENESIS STRENGTHENS THROUGH THE DAY AND MOVES EAST ACROSS THE
AREA AHEAD OF THIS SECOND SHORT WAVE TROUGH. CAPE WILL BE AROUND
1000J/KG OR LESS SO DO NOT ANTICIPATE A SEVERE THREAT SINCE THE CAPE
PROFILE WILL BE TALL AND NARROW WHICH FAVORS HEAVY RAINFALL. MEAN
STORM MOTION WILL CONTINUE TO BE AROUND 20MPH ALSO FAVORING HEAVY
RAINFALL. ANTICIPATE THE RAINFALL TO END FROM WEST TO EAST DURING
THE AFTERNOON AS THE UPPER LEVEL SHORT WAVE TROUGH EXITS THE AREA.
DUE TO THE COUPLE ROUNDS OF HEAVY RAINFALL POSSIBLE...A FLASH FLOOD
WATCH MAY BE NEEDED BUT WILL HOLD OFF FOR NOW IN ORDER TO GET A GOOD
HANDLE AS TO WHERE THE FLOODING THREAT WILL BE MOST LIKELY.
FRIDAY EVENING THERE MAY BE SOME LINGERING SHOWERS OVER THE EASTERN
PART OF THE AREA AS THE SHORT WAVE TROUGH MOVES EAST. DURING THE
LATE EVENING AND OVERNIGHT HOURS ANOTHER LESS COMPACT UPPER LEVEL
SHORT WAVE TROUGH WILL MOVE THROUGH THE AREA. CURRENTLY THE SOUTH
HALF TO 1/3 HAS THE BEST LIFT AND INSTABILITY SO WILL HAVE THE
HIGHER RAINFALL CHANCES THERE.
SATURDAY THROUGH WEDNESDAY NUMEROUS UPPER LEVEL SHORT WAVE TROUGHS
MOVE ACROSS THE AREA. TWO STRONGER SHORT WAVE TROUGHS WILL MOVE
THROUGH MONDAY AFTERNOON AND MONDAY NIGHT. AS A RESULT WILL HAVE
HIGHER RAINFALL CHANCES FOR MONDAY NIGHT. OTHERWISE LOW RAINFALL
CHANCES ARE FORECAST FOR VARIOUS PARTS OF THE AREA AS THE WEAKER
UPPER LEVEL DISTURBANCES MOVE THROUGH.
TEMPERATURES FOR THE PERIOD WILL START OFF COOLER THAN NORMAL THEN
GRADUALLY WARM TO NEAR NORMAL AS THE COOLER AIR MASS MOVES EAST OF
THE AREA. WEDNESDAY ANOTHER COLD FRONT WILL MOVE INTO THE AREA
BRINGING BELOW NORMAL TEMPERATURES WITH IT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1100 PM MDT WED SEP 3 2014
VFR CONDITIONS EXPECTED AT KGLD AND KMCK THROUGH THE PERIOD.
KGLD...SOUTHWEST WINDS 20KTS WITH HIGHER GUSTS AT TAF ISSUANCE
WILL REMAIN THROUGH 10Z. AROUND 11Z WINDS VEER TO THE SOUTHWEST
AROUND 12KTS THEN QUICKLY SHIFT TO THE NORTH/NORTHWEST AT 18G28KTS
POSSIBLY HIGHER BY 14Z AS A COLD FRONT AND NICE 3 HOUR PRESSURE
RISE COUPLET MOVE THROUGH. AROUND 18Z WINDS SUBSIDE JUST A BIT AS
THE COUPLET MOVES AWAY BUT STILL EXPECTING NORTH WINDS GUSTING A
BIT OVER 20KTS. BY 23Z A SLOW VEER TO THE NORTHEAST EXPECTED WITH
SPEEDS AROUND 13KTS. MODELS HINT AT A BIT OF MOISTURE AROUND 2K
FT DURING THE THE FRONTAL PASSAGE...RIGHT NOW NOT EXPECTING A BKN
DECK AT MVFR CATEGORY. PRECIPITATION CHANCES SHOULD HOLD OFF TIL
05Z WHEN SHOWERS/THUNDERSTORMS APPROACH THE TERMINAL FROM THE
SOUTHWEST.
KMCK...SOUTH WINDS AROUND 13KTS AT TAF ISSUANCE EXPECTED FOR A FEW
HOURS BEFORE FALLING JUST BELOW 12KTS BY 08Z. COLD FRONT MOVES
THROUGH AROUND 14Z WITH NORTH WINDS 17G27KTS AS PRESSURE RISE
COUPLET MOVES THROUGH. BY 22Z WINDS VEER TO THE NORTHEAST AROUND
13KTS. SIMILAR TO KGLD MOISTURE AROUND 2.5K FT MAY PRODUCE A FEW
CLOUDS FOR A FEW HOURS AROUND 14Z...NOT EXPECTED ENOUGH TO CREATE
A BKN DECK AND HIT MVFR CATEGORY. NO PRECIPITATION EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1149 PM CDT Wed Sep 3 2014
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Thursday)
Issued at 345 PM CDT WED SEP 3 2014
Water vapor loop shows relatively zonal flow across the Central
Plains with weak disturbances moving through. One vort max appears
to be along the border between northwest KS and southwest NE and
seems to be associated with thunderstorm cluster moving into eastern
Nebraska. HRRR has been the only model that developed convection
into central KS this evening, and has done so for the last several
runs. RAP just recently has forecast precip into same general area
in the next several hours. Meanwhile, all other models are keeping
central and eastern KS dry tonight. Confidence is not high enough
that HRRR is right, and thus have continued with POPs below 20% for
tonight in forecast area.
Good pressure gradient across the area tonight will maintain
southerly winds of 10 to 15 kts most areas. This should help keep
minimum temperatures up in the lower to middle 70s.
On Thursday, more sunshine than today and warm temperature aloft
will allow highs to reach the mid 90s most areas. Combined with
dewpoints generally in the upper 60s to lower 70s, peak afternoon
heat indices should reach the 100 to 105 range. Frontal boundary
approaches northwest corner of our CWA around 21Z on Thursday, thus
the chance of late afternoon thunderstorms is continued in that
area.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 345 PM CDT WED SEP 3 2014
Models are in good agreement that the cold front will traverse the
county warning area Thursday night into midday Friday...although
the GFS is the fastest. Convection that develops along and front
Thursday night will have the greatest impact with coverage and
rainfall amounts across the northern 1/3 of the cwa through sunrise
Friday as the front advances southeastward. Will range pops from
likely in the northwest counties to only a slight chance in the
far southeast near Garnett...then keep higher end chance pops all
areas on Friday along and behind the frontal passage and the
approach of a shortwave trough from the central high plains. This
wave will move east of the cwa early Saturday with diminishing
chances for rain north to south as much drier air overspreads the
area. With the frontal passage/cold air advection/clouds and
precip in the area will see much cooler highs from the upper 60s
around Belleville to the middle 80s south of I 35.
This will set the stage for lows in the 50s most areas Friday night
and Saturday night. With the dry air in place and high pressure
center over the area...will keep the area dry late Saturday through
Sunday with highs in the 70s both days.
With the flow aloft slowly transitioning from northwest on Saturday
to a more unsettled west to southwest flow into next week. As it
does...the chances for more thunderstorms will increase and so
will the high temperatures ahead of the next front which is
expected by early Wednesday as a larger scale upper trough moves
into the plains.
Will introduce pops in the north central by Sunday night and then
across the remainder of the cwa Monday into Wednesday.
Highs will generally be in the 80s...cooling slightly into the upper
70s and lower 80s by Wednesday.
&&
.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1147 PM CDT WED SEP 3 2014
VFR conditions expected through most of the taf sites. There may
be an occasional gusts under 20 kts at TOP/FOE overnight. As a
front approaches tomorrow there is a slight chance that
thunderstorms developing along that front could reach the taf sites
towards the end of the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GDP
LONG TERM...63
AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
522 AM EDT THU SEP 4 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU SEP 4 2014
AS FIGURED IT HAS BEEN A FAIRLY ACTIVE NIGHT AT LEAST IN TERMS OF
SHRA/TSRA. NO SEVERE WEATHER IN OUR CWA...WITH BULK OF TSRA STAYING
MAINLY OVER SOUTHERN CWA EARLIER TONIGHT. VERY HEAVY RAIN DID OCCUR
EARLIER AS KIMT AND KMNM BOTH ENDED UP WITH AROUND AN INCH OF RAIN
IN 45-60 MIN. STRONGEST STORMS IN THE AREA NOW ARE CROSSING CNTRL LK
MICHIGAN. A LULL HAS DEVELOPED OVER UPR MICHIGAN...EXCEPT VERY FAR
EAST WHERE RAIN AND EMBEDDED TSRA WILL RUN ITS COURSE OVER NEXT
COUPLE HOURS.
WESTERLY FLOW ALOFT AND THE MAIN SHORTWAVE IS DRIVING ACROSS
SOUTHERN SASKATCHEWAN AND INTO WESTERN NORTH DAKOTA. SPC
MESOANALYSIS PAGE SHOWS ISOLD-SCT STRONG-SEVERE STORMS OVER NORTH
DAKOTA ARE FORMING IN WARM AIR ADVECTION REGION ALONG AND NORTH OF
GRADIENT OF 1-6KM MUCAPE OF 2000-3000 J/KG MAXIMIZED FM SOUTHERN TO
CENTRAL PLAINS. ACTIVITY IS ALSO JUST NORTH OF THE +12C ISOTHERM AT
H7. CONVECTIVELY INDUCED WAVE IS ALSO FORMING OVR NORTH DAKOTA PER
WV LOOP AND REGIONAL RADAR LOOPS. HIGH RES MODELS...SUCH AS THE HRRR
AND NSSL WRF AND WRF-ARW/NMM BEGAN TO PICK UP ON THIS LATE WED
EVENING AND CONTINUE TO INDICATE THIS MCV WITH ASSOCIATED MCS WILL
CONTINUE TRACKING EAST ALONG MUCAPE/H85 DWPNT GRADIENT AND WITH THE
H85-H3 WEST TO EAST ORIENTED THICKNESS LINES AND FOLLOWING THE
FORWARD PROPAGATING CORFIDI VECTORS. CERTAINLY POSSIBLE THIS COMPLEX
MAY GROW UPSCALE/PRODUCE WIDESPREAD SEVERE WX GIVEN THE SUFFICIENT
EFFECTIVE SHEAR OVER 40 KTS PRESENT FM DAKOTAS ACROSS MINNESOTA AND
ALSO DUE TO THE FAVORABLE 0-3KM SHEAR OVER 30 KTS THAT WOULD HELP
THE SHEAR/COLD POOL BALANCE NEEDED TO SUSTAIN SUCH A COMPLEX. SFC
WARM FRONT STILL WELL TO THE SOUTHWEST OF HERE THIS MORNING...MOST
LIKELY OVER SOUTHERN MINNESOTA TO SOUTHWEST WISCONSIN. SEEMS THAT
THIS COMPLEX WOULD HAVE TO TAKE A VERY HARD TURN RIGHT...AND QUICKLY
FOR IT TO NOT IMPACT UPR GREAT LAKES LATER THIS MORNING OR MAYBE NOW
AS LATEST HRRR SHOWS...EARLY AFTN. THE LATER ARRIVAL OF A COMPLEX...
ALSO A GREATER SEVERE THREAT FOR WIND/HAIL OVER OUR CWA. CONFIDENCE
IS NOT HIGH ENOUGH TO PUT SEVERE MENTION IN GRIDS...BUT WILL CONTINUE
TO MENTION IN HWO AND VARIOUS SOCIAL MEDIA.
UNFORTUNATELY...SINCE THIS AREA OF TSRA IS A NEW DEVELOPMENT
COMPARED TO EXPECTED SHRA/TSRA EVOLUTION FOR TODAY LOOKED LIKE
12-24 HR AGO HAD TO REWORK POPS/WX CONSIDERABLY THROUGH MID AFTN
TODAY. WHATEVER COMPLEX WORKS ACROSS UPR MICHIGAN SHOULD BE ON THE
WANE AFT 18Z-21Z. WARM FRONT PROBABLY WILL HAVE TOUGH TIME MAKING IT
TO THE CWA TODAY GIVEN THE SHRA/TSRA THAT WENT THROUGH OVERNIGHT AND
THIS ADDITIONAL AREA OF TSRA POSSIBLE LATER TODAY. CAPPING THAT
LOOKED SO FIERCE FOR THIS AFTN 24 HR AGO...NOW NOT AS MUCH...
POSSIBLY BECAUSE THE ATMOSPHERE WILL BE WORKED OVER FROM SHRA/TSRA
MOVING IN FM NORTH DAKOTA LATER TODAY. THUS...THINK THAT THE H85
MOISTURE TRANSPORT INTO AN AREA OF MID-LEVEL FGEN WILL BE ENOUGH TO
REDEVELOP SHRA/TSRA OVER WESTERN CWA BY LATE THIS AFTN. ADDITIONAL
POTENTIAL FOR SEVERE WITH THIS ACTIVITY AS WELL GIVEN MLCAPES AROUND
1500 J/KG AND EFFECTIVE SHEAR 40-55 KTS. SUPERCELL STRUCTURES WOULD
STILL BE POSSIBLE WITH RIGHT MOVING SUPERCELLS SHOWING A WEST-EAST
MOTION WHILE LEFT MOVERS WOULD MOVE MORE SOUTHWEST TO NORTHEAST.
MEAN STORM MOTION WOULD BE WEST SOUTHWEST TO EAST NORTHEAST. ALL
MOTIONS ARE SWIFT...PROBABLY IN THE 30-40 MPH RANGE.
IN REGARDS TO SPECIFIC SEVERE POTENTIAL...SPC HAS OUR AREA FIRMLY IN
THE 15 PCT RISK FOR SEVERE HAIL AND DAMAGING WINDS. THIS COULD OCCUR
WITH THIS INITIAL COMPLEX IF IT MAKES INTO THE AREA. LIKELY DAMAGING
WINDS WOULD BE THE MAIN THREAT IF THAT OCCURS. IF ADDITIONAL STORMS
CAN REDEVELOP IN WAKE OF THIS ACTIVITY LATE THIS AFTN/EARLY THIS
EVENING AHEAD OF STRONG COLD FRONT...THE DEGREE OF SHEAR INDICATES
SUPERCELLS WOULD BE POSSIBLE ESPECIALLY IF MLCAPES RECOVER TOWARD
1500-2000 J/KG. ALL SEVERE MODES COULD OCCUR LATE THIS AFTN IF THAT
OCCURS...EVEN POTENTIAL FOR TORNADOES AS 0-1KM SHEAR IS OVER 30 KTS
AND ML LCL/S HEIGHTS WOULD BE VERY FAVORABLE AT LESS THAN 1000M.
FREEZING LEVELS MAINLY BLO 13KFT AND MODELS INDICATE WOULD HAVE TO
SEE CORES GET TO 30-35KFT FOR QUARTER SIZED HAIL. THIS SEEMS VERY
ACHIEVABLE GIVEN THE SHEAR AND INSTABILITY FORECAST. THE WILD CARD IS
EXTENT OF INSTABILITY THAT WILL BE LEFT IN WAKE OF THE INITIAL
COMPLEX. MODELS COULD BE OVERPLAYING THAT...AND THUS THE ADDITIONAL
SEVERE THREAT. TIME WILL TELL.
LARGER SCALE FORCING IN TERMS OF SHORTWAVE AND DEEP LAYER LIFT
SWINGS ACROSS THE CWA FM WEST TO EAST AND EXPECT SCT-NMRS SHOWERS
AND TSRA IN THE EVENING. MAY BE AT LEAST SOME LINGERING RISK OF
STRONGER STORMS DURING THIS TIME. DRYING PUNCHES IN IN MID-LEVELS
OVERNIGHT AND COLD FRONT ARRIVES. EXPECT SHRA/TSRA CHANCES TO BE
WANING OVER THE EAST CWA AFTER 08Z.
FINALLY...GRADIENT WINDS WILL BE VERY GUSTY...FIRST OVER NORTHERN LK
MICHIGAN TODAY IN THE SOUTH-SOUTHWEST FLOW...THEN LATE TONIGHT OVER
LK SUPERIOR IN WAKE OF THE FRONT WHEN WINDS SHIFT TO THE WEST
NORTHWEST. ISALLOBARIC ADDITION TO THE WIND COULD LEAD TO MARGINAL
GALES IN BOTH OF THESE AREAS...AT LEAST FOR A FEW HOURS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 451 AM EDT THU SEP 4 2014
FRI...EXPECT ANY LINGERING SHRA/TSRA OVER THE FAR ERN CWA TO DEPART
BY MID MORNING. OTHERWISE...CAA DROPPING 850 MB TEMPS INTO THE 6C-8C
RANGE WILL KEEP MAX READINGS IN THE LOWER 60S WEST TO AROUND 70 NEAR
LAKE MICHIGAN. AS THE STRONG LOW OVER NRN ONTARIO LIFTS NE INTO NRN
QUEBEC AND HIGH PRESSURE OVER THE PLAINS BUILDS INTO THE WRN GREAT
LAKES...GUSTY WNW WINDS WILL GRADUALLY DIMINISH. HOWEVER...WINDS
GUSTING TO AROUND 30 KNOTS MAY BE POSSIBLE EARLY OVER THE
KEWEENAW...ESPECIALLY FOR THE WEST FACING HIGHER TERRAIN.
FRI NIGHT INTO SUNDAY...DRY WEATHER IS EXPECTED TO PREVAIL AS THE
REGION REMAINS UNDER THE INFLUENCE OF HIGH PRESSURE THAT GRADUALLY
BUILDS INTO THE SRN GREAT LAKE. PCPN ASSOCIATED WITH SHRTWVS MOVING
THROUGH NRN ONTARIO BOTH FRI NIGHT AND SAT NIGHT SHOULD REMAIN NORTH
OF LAKE SUPERIOR GIVEN THE DRY AIRMASS OVER THE REGION. THE MAIN
IMPACT ON UPPER MI WILL BE TO REINFORCE THE SEASONABLY COOL AIR.
MON-WED...THE GFS/GEFS AND ECWMF WERE IN GENERAL AGREEMENT THAT THE
ZONAL PATTERN MONDAY WILL GIVE WAY TO TROUGHING INTO THE NRN PLAINS
SHIFTING TOWARD THE UPPER MS VALLEY. THERE ARE DIFFERENCES IN
HANDLING THE DETAILS OF THE TIMING/STRENGTH OF THE PLAINS TROUGH AND
A MORE DOMINANT LOW NEAR HUDSON BAY. WITH BOTH THE MID LEVEL AND SFC
TROUGH APPROACHING THE AREA...PCPN CHANCES WILL INCREASE FROM TUE
INTO WED. HOWEVER...PCPN AMOUNTS WILL GENERALLY BE LIGHT WITH ONLY A
SLIGHT CHANCE FOR TSRA...MAINLY ON TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 133 AM EDT THU SEP 4 2014
SHRA THAT ARE MOVING ACROSS UPPER MI HAVE ALREADY MOVED E OF THE
KIWD/KCMX AREAS AND WILL BE E OF KSAW IN THE NEXT HR OR TWO. VFR
CONDITIONS WILL START THE FCST PERIOD...BUT TOWARD DAYBREAK AND INTO
THE MORNING HRS...LOW CLOUDS MAY EXPAND NORTHWARD BEHIND THE
DEPARTING AREA OF PCPN OVER THE UPPER LAKES. KEPT THE IDEA OF MVFR
CIGS DEVELOPING AT ALL TERMINALS...BUT NOT OUT OF THE QUESTION THAT
IFR COULD DEVELOP...MAINLY AT KSAW WHERE UPSLOPE WINDS WILL BE MORE
FAVORABLE. LOWER CLOUDS SHOULD SCATTER OUT BY EARLY AFTN.
MEANWHILE...SOME OF THE SHRA/TSTMS CURRENTLY OVER THE DAKOTAS MAY
HOLD TOGETHER...BRINGING THE POTENTIAL FOR PCPN AT ALL THE TERMINALS
MID MORNING TO EARLY AFTN. WITH LOW CONFIDENCE...ONLY INCLUDED A
VCSH MENTION...BUT THIS MAY NEED MORE OF A MENTION FOR 12Z TAFS.
THEN...APPROACHING COLD FRONT MAY TRIGGER ISOLD/SCT STRONG TO SVR
TSTMS LATER THIS AFTN/EVENING...BUT CONFIDENCE IN DEVELOPMENT OF PCPN
IS VERY LOW AT THIS POINT. MODEL FCST GUIDANCE SUGGESTS KSAW MAY HAVE
A BETTER POTENTIAL FOR CONVECTION...SO ONLY OPTED FOR A VCTS MENTION
AT THAT TERMINAL IN THE EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 AM EDT THU SEP 4 2014
A LOW PRESSURE SYSTEM OVER THE EASTERN DAKOTAS WILL LIFT TO THE
NORTHEAST THROUGH NRN MN TODAY AND TO JAMES BAY BY FRIDAY MORNING.
MOIST AIR MOVING OVER THE LAKE UNDER SOUTHEASTERLY WINDS WILL LEAD
TO PATCHY/AREAS OF FOG OVER PORTIONS OF THE LAKE TONIGHT THROUGH
FRIDAY MORNING. A COLD FRONT MOVING EAST ACROSS LAKE SUPERIOR
TONIGHT WILL BRING GUSTY WESTERLY WINDS TO 30KTS THROUGH FRIDAY
MORNING. WINDS WILL DIMINISH FRIDAY AFTERNOON/NIGHT AS A HIGH
PRESSURE RIDGE BUILDS OVER THE UPPER GREAT LAKES REGION. THIS WILL
LEAD TO LIGHT WINDS THROUGH THE WEEKEND AND THE FIRST PART OF NEXT
WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
325 AM CDT THU SEP 4 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM CDT THU SEP 4 2014
MAIN CONCERNS WITH THIS PERIOD ARE THE FORWARD PROPAGATING MCS THAT
IS EXPECTED TO DEVELOP AND RACE ACROSS CENTRAL MN EARLY THIS
MORNING. THIS WILL BE FOLLOWED BY HOT AND HUMID TEMPERATURES ACROSS
EASTERN MN AND WESTERN WI...WITH A FEW SHOWERS AND THUNDERSTORMS
POSSIBLE BY LATE AFTERNOON. MEANWHILE A SEASONABLY STRONG COLD FRONT
WILL PUSH THROUGH THE REGION AND BRING BREEZY NORTHWESTERLY WINDS
OVERNIGHT ALONG WITH COOL/DRY AIR.
THE FIRST ORDER OF DISCUSSION IS THE SEVERE WEATHER THREAT THIS
MORNING RELATED TO THE CONVECTION ACROSS NORTH DAKOTA. HIRES MODELS
SUCH AS THE HRRR AND 00/03Z RUNS OF THE HOPWRF ARE IN REMARKABLE
AGREEMENT THAT THIS CONVECTION WILL INTENSIFY AS IT MOVES INTO
WESTERN MINNESOTA AND DEVELOP INTO A BOW ECHO. THIS STORM MODE SEEM
VERY PLAUSIBLE CONSIDERING THE ORIENTATION OF THE DEEP LAYER SHEAR
VECTORS IN RELATION TO THE WARM FRONT AND MUCAPE GRADIENT...SO
INCLUDED DAMAGING WINDS IN THE FORECAST ACROSS THE FAR NORTHERN TIER
OF COUNTIES. THE HRRR SEEMS TO HAVE A BETTER HANDLE ON THE ONGOING
CONVECTION...AND IT KEEPS THE MAJORITY OF THE FORECAST PRECIP NORTH
OF THE CWA. HOWEVER BASED ON THE ACTUAL LOCATION OF THE WARM FRONT
STILL THINK THERE IS LEGITIMATE RISK ALONG AND NORTH OF A LINE FROM
ALEXANDRIA MN TO RICE LAKE WI.
AS THE COLD POOL BECOMES WELL ESTABLISHED THIS CONVECTION WILL RACE
EASTWARD. MEANWHILE THE UPPER LEVEL WAVE AND SURFACE LOW WILL SLOWLY
MAKE THEIR WAY INTO NORTHERN MN ALLOWING THE WARM SECTOR TO
DESTABILIZE THROUGHOUT THE DAY ON THURSDAY. DEPENDING ON THE
RESIDUAL CLOUD COVER...AFTERNOON HIGH TEMPS COULD EASILY CLIMB INTO
THE 90S ACROSS SOUTHEASTERN MN AND WESTERN WI. FOR NOW DID NOT GO
MUCH ABOVE GUIDANCE SINCE SHOWERS AND THUNDERSTORMS COULD DEVELOP
ALONG THE TRAILING COLD FRONT LIMITING THE DIABATIC HEATING. A FEW
OF THESE STORMS ARE LIKELY TO BE SEVERE AS FORECAST SOUNDINGS
SHOW NEARLY 4000J/KG OF CAPE BY LATE AFTERNOON AND AROUND 30KTS OF
DEEP LAYER SHEAR ALONG AND EAST OF THE MN/WI BORDER.
THIS AFOREMENTIONED COLD FRONT IS THE LAST REAL AREA OF INTEREST.
AGAIN FORECAST SOUNDINGS SHOW STRONG COLD AIR ADVECTION IN THE WAKE
OF THE FRONT. THIS WILL KEEP THE BOUNDARY LAYER WELL MIXED WITH
NORTHWESTERLY WIND GUSTS OF 20 TO 30MPH EXPECTED TO PREVAIL AFTER
DARK. THEREFORE INCREASED THE WINDS THURSDAY NIGHT...AND USED LESS
BIAS-CORRECTED GRIDS FOR OVERNIGHT LOWS SINCE THE TEMPERATURES
SHOULD BE RATHER UNIFORM. ALSO RAISED CLOUD COVER SINCE SOUNDINGS
SHOW SATURATION ABOVE THE BOUNDARY LAYER.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 AM CDT THU SEP 4 2014
THE FIRST HALF OF THE LONG TERM LOOKS RATHER QUIET. THERE WILL BE
A SPLIT FLOW PATTERN DEVELOPING WITH THE SUBTROPICAL JET TO THE
SOUTH KEEPING THE HEAT CONFINED TO THE SOUTHERN STATES...AND THE
POLAR JET ACROSS CENTRAL CANADA KEEPING THE UNSEASONABLY COOL AIR
TO THE NORTH - AT LEAST FOR THE TIME BEING. SURFACE HIGH PRESSURE
WILL GUARANTEE MOSTLY CLEAR SKIES THROUGH SUNDAY NIGHT.
THINGS BECOME A BIT MORE COMPLEX NEXT WEEK AS THE POLAR JET
BEGINS TO SINK SOUTH. A MORE ACTIVE PATTERN IS IN THE OFFING WITH
SEVERAL DISTURBANCES SKIRTING ALONG THE NORTHERN TIER OF THE U.S.
HOWEVER...WITH THE SUBTROPICAL JET REMAINING SOUTH IT DOES NOT
APPEAR ANY OF THESE DISTURBANCES WILL HAVE A WHOLE LOT OF MOISTURE
TO WORK WITH. THEREFORE KEPT POPS IN THE CHC RANGE.
EVENTUALLY THE JETS WILL PHASE AND CARVE OUT A DEEP TROUGH OVER
CANADA AND THE NORTHERN U.S. SOME TIME DURING THE MIDDLE OF NEXT
WEEK. THE MUCH COOLER TEMPS ACCOMPANYING THIS TROUGH SHOULD MARK
THE FIRST CRACK AT AUTUMN WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1057 PM CDT WED SEP 3 2014
CONVECTION WILL AFFECT KEAU AT THE START OF THE TAF PERIOD...AND
THEN A LULL IN THE ACTIVITY IS EXPECTED WITH LOWERING CIGS
BECOMING THE PRIMARY CONCERN UNTIL THE NEXT BATCH OF SHOWERS AND
THUNDERSTORMS APPROACHES FROM THE WEST. NAM AND GFS GUIDANCE PROG
EXTENSIVE IFR CIGS TO DEVELOP OVERNIGHT...HOWEVER...TRENDS HAVE
NOT BEEN SUPPORTING THAT THEORY THUS FAR. SO...WILL LEAN TOWARD
THE 04.02Z RAP13 0.5 KM AGL CONDENSATION PRESSURE DEFICIT
PROG...WHICH BOTTLES THE MVFR/IFR CIGS OVER CENTRAL MN JUST NORTH
OF THE WARM FRONT. THIS MEANS THE MOST NOTABLE CIG REDUCTIONS
WOULD BE EXPERIENCED AT KAXN AND KSTC...POSSIBLY ARCING DOWN
TOWARD KRNH AND KEAU. KMSP WOULD BE ON THE EDGE...SO HAVE GONE A
BIT MORE OPTIMISTIC WITH CIGS THERE...BUT STILL FEATURE A PERIOD
OF MVFR/IFR OVERNIGHT. IN ADDITION TO CIGS...ANOTHER CONCERN IS
THE POTENTIAL FOR CONVECTION TO DEVELOP OVERNIGHT OVER THE DAKOTAS
AND SPREAD EASTWARD INTO THE AREA DURING THE EARLY MORNING HOURS
ON THURSDAY. RIGHT NOW THINK KAXN AND KSTC ARE THE MOST
SUSCEPTIBLE TO EXPERIENCING SAID ACTIVITY...BUT CONFIDENCE ON
DEVELOPMENT IS ADMITTEDLY LOW. THINK ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS WILL DEVELOP AS THE COLD FRONT MOVES ACROSS THE
AREA. HAVE INCLUDED PROB30S AS CONFIDENCE IN TIMING/COVERAGE IS
LOW. EAST/SOUTHEAST WINDS SHIFT TO NORTHWEST ON THURSDAY IN THE
WAKE OF THE FRONT...AND BECOME GUSTY.
KMSP...
HAVE GONE A BIT MORE OPTIMISTIC WITH CIGS OVERNIGHT...BUT STILL
THINK CIGS WILL DIP BELOW 1700 FT OVERNIGHT...WITH MVFR BR
POSSIBLE AS WELL. COULD SEE A FEW SHOWERS APPROACHING THE FIELD
AFTER DAYBREAK /WITH DAKOTAS ACTIVITY WANING AS IT
APPROACHES/...BUT A SLIGHTLY HIGHER PROBABILITY WILL BE WITH THE
COLD FRONT AFTER 21Z.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS NW 10G15 KTS.
SAT...VFR. WINDS W 5-10 KTS.
SUN...VFR. WINDS SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
152 AM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 155 AM CDT THU SEP 4 2014
WILL ALLOW THE MAJORITY OF THE SEVERE THUNDERSTORM WATCH TO EXPIRE
AT 2AM CDT. WILL EXTEND/ISSUE A NEW SEVERE THUNDERSTORM WATCH FOR
ONGOING SEVERE STORMS...BASICALLY ALONG I94 AND A COUNTY NORTH AND
SOUTH FROM BISMARCK EAST. THIS WILL BE VALID UNTIL 12Z...BUT
FULLY EXPECT WE WILL EXPIRE BEFORE ONCE ACTIVITY MOVES OUT OF THE
BISMARCK CWA.
UPDATE ISSUED AT 106 AM CDT THU SEP 4 2014
CONVECTION CONTINUES TO PUSH EAST...AND HAVE REMOVED ANOTHER TIER
OF COUNTIES ON THE WESTERN EDGE OF THE WATCH. AN EXTENSION OR NEW
SEVERE THUNDERSTORM WATCH MAY BE NEEDED ACROSS MY EAST. EVALUATING
NOW.
UPDATE
ISSUED AT 1150 PM CDT WED SEP 3 2014
QUICK UPDATE TO REMOVE A FEW COUNTIES ACROSS WESTERN NORTH DAKOTA.
SURFACE COLD FRONT HAS MOVED THROUGH THE FAR WEST AND THE SEVERE
THREAT HAS DECREASED GREATLY THERE. FARTHER EAST...TWO CONVECTIVE
SYSTEMS CONTINUE TO PRODUCE SEVERE WEATHER...ONE OVER EASTERN DUNN
AND THE OTHER OVER EASTERN MCLEAN. UPDATED POPS BASED ON LATEST
RADAR AND NEAR TERM MODELS.
UPDATE ISSUED AT 916 PM CDT WED SEP 3 2014
THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA HAVE INCREASED IN
COVERAGE OVER THE PAST COUPLE HOURS. HAVE INCREASED POPS ACROSS
THE SOUTHWEST AND CENTRAL PART OF THE STATE WITH THE HRRR AND RAP
SHOWING HIGHER THUNDERSTORM CHANCES FOR THOSE LOCATIONS.
UPDATE ISSUED AT 640 PM CDT WED SEP 3 2014
ISOLATED SEVERE THUNDERSTORM CONTINUES TO TRACK EAST ACROSS
NORTHWEST NORTH DAKOTA...WITH ADDITIONAL STRONG CONVECTION OVER
NORTHEAST MONTANA. SURFACE BASED CONVECTION HAS YET TO DEVELOP
OVER WESTERN NORTH DAKOTA BUT SUCCESSIVE RUNS OF THE HRRR HAVE
INDICATED SCATTERED CONVECTION ACROSS THE SOUTHWEST AND MOVING
INTO THE SOUTH CENTRAL. LATEST RUN IS HINTING MORE AT THE
CONVECTION IN NORTHEAST MONTANA TRACKING ACROSS THE NORTHWEST AND
NORTH CENTRAL. WILL NEED TO MONITOR FOR POSSIBLE CONVECTIVE WATCH
THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHEAST MONTANA WITH
MOISTURE CONTINUING TO SLOWLY WRAP UP INTO CENTRAL NORTH DAKOTA
AHEAD OF IT. UPPER LEVEL ANALYSIS PLACES TROUGH/LOW PUSHING FORWARD
INTO EASTERN MONTANA. INITIAL WAVE EJECTING AHEAD OF THE TROUGH
CONTINUES TO PRODUCE CONVECTION OVER NORTHEAST MONTANA. FORECAST
CHALLENGES FOR TODAY INCLUDE THE SEVERE POTENTIAL LATE TODAY INTO
TONIGHT...AND THEN GUSTY WINDS ON THURSDAY.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...UPPER TROUGH WILL
CONTINUE ITS EASTWARD PUSH WITH BROAD SCALE LIFT CONTINUING TO
INCREASE FROM WEST TO EAST. MOISTURE WILL CONTINUE TO INCREASE AS
LOW SLOWLY SHIFTS TOWARDS NORTH CENTRAL SOUTH DAKOTA. INITIAL
DISCRETE STORMS THAT DEVELOP WILL ENCOUNTER INCREASING INSTABILITY
ALONG WITH IMPRESSIVE DEEP LAYER SHEAR. EXPECT INITIAL STORMS WILL
HAVE A MAINLY HAIL THREAT ALONG WITH A STRONG WIND THREAT. AS TIME
GOES ON AND STORM DEVELOPMENT WORKS EASTERLY ENCOUNTERING HIGHER
MOISTURE...THERE MAY BE A BRIEF TORNADO THREAT IF THE STORMS CAN
BE SURFACE BASED. WITH THAT SAID...THE HAIL AND WIND THREAT WILL
CONTINUE INTO THE LATE EVENING. FOCUS FOR SEVERE WILL SHIFT OVER
MAINLY CENTRAL INTO EASTERN NORTH DAKOTA OVERNIGHT AS PLUME OF
STRONG INSTABILITY REMAINS WITH STRONG THETA-E ADVECTION...WHILE
OVER THE WEST ATMOSPHERE WILL STABILIZE. STORMS SHOULD ALL BE
PUSHED OFF TO THE EAST BY SUNRISE WITH SHOWERS LINGERING.
ON THURSDAY...SOME SHOWERS WILL REMAIN PRIMARILY OVER THE NORTHERN
AND EASTERN PART OF THE STATE AS UPPER TROUGH MAKES ITS WAY EAST.
PRIMARY CONCERN WILL BE GUSTY WEST TO NORTHWESTERLY WINDS
DEVELOPING AS COLD AIR POURS INTO THE AREA WITH TIGHT PRESSURE
GRADIENT AS LOW SHIFTS INTO MINNESOTA. STRONGEST WINDS LOOK TO BE
OVER SOUTHWEST NORTH DAKOTA IN THE MORNING...WITH WINDS
DIMINISHING IN THE AFTERNOON AS GRADIENT RELAXES AND COLD AIR
ADVECTION DECREASES. TEMPERATURES WILL BE SEASONABLY COOL WITH
MANY LOCATIONS AROUND 10-15 DEGREES BELOW AVERAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
A NORTHWEST FLOW ALOFT IS MAINTAINED THURSDAY NIGHT INTO
SATURDAY...THEN TRANSITIONS TO A ZONAL FLOW SUNDAY INTO WEDNESDAY. A
MORE ACTIVE PERIOD WILL EVOLVE DURING THE ZONAL FLOW PERIOD AS A
STRONG SHORTWAVE TROUGH AND ASSOCIATED POTENT COLD FRONT IS SLATED
TO SWEEP THROUGH TUESDAY INTO WEDNESDAY...WITH SEVERE WEATHER POSSIBLE.
GUSTY NORTHWEST WINDS THURSDAY EVENING WILL QUICKLY SUBSIDE AS A
SURFACE HIGH PRESSURE SLIDES ACROSS SOUTHWEST NORTH DAKOTA EARLY
THURSDAY NIGHT AND INTO CENTRAL SOUTH DAKOTA BY 12Z FRIDAY. A CLEAR
SKY...GOOD RADIATIONAL COOLING...AND DEWPOINTS IN THE UPPER 30S LOOK
REASONABLE TO SUPPORT OVERNIGHT LOWS IN THE UPPER 30S ACROSS THE
SOUTHWEST...ESPECIALLY OVER THE NORMAL COLDER LOCATIONS SUCH AS
HETTINGER. HENCE HAVE LOWERED MINIMUM TEMPERATURES INTO THE UPPER
30S UNDER THIS WEATHER PATTERN. OVERALL...A QUIET/PLEASANT WEATHER
PATTERN CONTINUES FRIDAY/SATURDAY WITH A SLOW MODERATING TREND. H85
TEMPS BEGIN TO WARM LEADING TO HIGHS INTO THE 70S SATURDAY AND
SUNDAY. THERE WILL BE A SUBTLE DRY COLD FRONTAL PASSAGE SATURDAY
AFTERNOON...HOWEVER OTHER THAN A WINDSHIFT TO THE NORTHWEST...NOT
EXPECTING MUCH OF A TEMPERATURE CHANGE.
A MORE ACTIVE WEATHER PATTERN SLOWLY BEGINS TO EMERGE SUNDAY NIGHT
AS A WEAK SHORTWAVE SLIDES THROUGH WITH WARM AIR ADVECTION PROCESSES
TAKING OVER. A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS ARE POSSIBLE
SUNDAY NIGHT INTO MONDAY MAINLY FOR THE JAMES RIVER VALLEY. THE
WARMEST DAY WILL BE MONDAY WITH HIGHS REACHING BETWEEN 75 AND 85.
THIS WILL BE FOLLOWED BY A STRONG COLD FRONT WHICH WILL APPROACH
NORTHWEST NORTH DAKOTA TUESDAY MORNING AND THEN SWEEP THROUGH
TUESDAY AFTERNOON/EVENING. A STRONG H85 BAROCLINIC ZONE SHIFTS
THROUGH TUESDAY NIGHT WITH THE 0C TO -2C ISOTHERM SETTLING INTO
CENTRAL NORTH DAKOTA WEDNESDAY. THIS TREND SETS THE STAGE FOR MUCH
COLDER AIR WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 106 AM CDT THU SEP 4 2014
SCATTERED CONVECTION THIS EVENING CONTINUES EAST ACROSS CENTRAL
NORTH DAKOTA AS A COLD FRONT MOVES THROUGH THE AREA. FLOW WILL
TURN WEST TO NORTHWEST LATE TONIGHT AND THURSDAY WITH AREAS OF
IFR-MVFR CLOUDINESS MOST LOCATIONS. STRONG NORTHWEST WINDS ON
THURSDAY WITH THE STRONGEST 20 TO 35 MPH AT KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 AM THIS MORNING TO 4 PM MDT THIS AFTERNOON
FOR NDZ031>033-040-041-043-044.
&&
$$
UPDATE...NH
SHORT TERM...JJS
LONG TERM...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
105 AM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 106 AM CDT THU SEP 4 2014
CONVECTION CONTINUES TO PUSH EAST...AND HAVE REMOVED ANOTHER TIER
OF COUNTIES ON THE WESTERN EDGE OF THE WATCH. AN EXTENSION OR NEW
SEVERE THUNDERSTORM WATCH MAY BE NEEDED ACROSS MY EAST. EVALUATING
NOW.
UPDATE
ISSUED AT 1150 PM CDT WED SEP 3 2014
QUICK UPDATE TO REMOVE A FEW COUNTIES ACROSS WESTERN NORTH DAKOTA.
SURFACE COLD FRONT HAS MOVED THROUGH THE FAR WEST AND THE SEVERE
THREAT HAS DECREASED GREATLY THERE. FARTHER EAST...TWO CONVECTIVE
SYSTEMS CONTINUE TO PRODUCE SEVERE WEATHER...ONE OVER EASTERN DUNN
AND THE OTHER OVER EASTERN MCLEAN. UPDATED POPS BASED ON LATEST
RADAR AND NEAR TERM MODELS.
UPDATE ISSUED AT 916 PM CDT WED SEP 3 2014
THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA HAVE INCREASED IN
COVERAGE OVER THE PAST COUPLE HOURS. HAVE INCREASED POPS ACROSS
THE SOUTHWEST AND CENTRAL PART OF THE STATE WITH THE HRRR AND RAP
SHOWING HIGHER THUNDERSTORM CHANCES FOR THOSE LOCATIONS.
UPDATE ISSUED AT 640 PM CDT WED SEP 3 2014
ISOLATED SEVERE THUNDERSTORM CONTINUES TO TRACK EAST ACROSS
NORTHWEST NORTH DAKOTA...WITH ADDITIONAL STRONG CONVECTION OVER
NORTHEAST MONTANA. SURFACE BASED CONVECTION HAS YET TO DEVELOP
OVER WESTERN NORTH DAKOTA BUT SUCCESSIVE RUNS OF THE HRRR HAVE
INDICATED SCATTERED CONVECTION ACROSS THE SOUTHWEST AND MOVING
INTO THE SOUTH CENTRAL. LATEST RUN IS HINTING MORE AT THE
CONVECTION IN NORTHEAST MONTANA TRACKING ACROSS THE NORTHWEST AND
NORTH CENTRAL. WILL NEED TO MONITOR FOR POSSIBLE CONVECTIVE WATCH
THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHEAST MONTANA WITH
MOISTURE CONTINUING TO SLOWLY WRAP UP INTO CENTRAL NORTH DAKOTA
AHEAD OF IT. UPPER LEVEL ANALYSIS PLACES TROUGH/LOW PUSHING FORWARD
INTO EASTERN MONTANA. INITIAL WAVE EJECTING AHEAD OF THE TROUGH
CONTINUES TO PRODUCE CONVECTION OVER NORTHEAST MONTANA. FORECAST
CHALLENGES FOR TODAY INCLUDE THE SEVERE POTENTIAL LATE TODAY INTO
TONIGHT...AND THEN GUSTY WINDS ON THURSDAY.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...UPPER TROUGH WILL
CONTINUE ITS EASTWARD PUSH WITH BROAD SCALE LIFT CONTINUING TO
INCREASE FROM WEST TO EAST. MOISTURE WILL CONTINUE TO INCREASE AS
LOW SLOWLY SHIFTS TOWARDS NORTH CENTRAL SOUTH DAKOTA. INITIAL
DISCRETE STORMS THAT DEVELOP WILL ENCOUNTER INCREASING INSTABILITY
ALONG WITH IMPRESSIVE DEEP LAYER SHEAR. EXPECT INITIAL STORMS WILL
HAVE A MAINLY HAIL THREAT ALONG WITH A STRONG WIND THREAT. AS TIME
GOES ON AND STORM DEVELOPMENT WORKS EASTERLY ENCOUNTERING HIGHER
MOISTURE...THERE MAY BE A BRIEF TORNADO THREAT IF THE STORMS CAN
BE SURFACE BASED. WITH THAT SAID...THE HAIL AND WIND THREAT WILL
CONTINUE INTO THE LATE EVENING. FOCUS FOR SEVERE WILL SHIFT OVER
MAINLY CENTRAL INTO EASTERN NORTH DAKOTA OVERNIGHT AS PLUME OF
STRONG INSTABILITY REMAINS WITH STRONG THETA-E ADVECTION...WHILE
OVER THE WEST ATMOSPHERE WILL STABILIZE. STORMS SHOULD ALL BE
PUSHED OFF TO THE EAST BY SUNRISE WITH SHOWERS LINGERING.
ON THURSDAY...SOME SHOWERS WILL REMAIN PRIMARILY OVER THE NORTHERN
AND EASTERN PART OF THE STATE AS UPPER TROUGH MAKES ITS WAY EAST.
PRIMARY CONCERN WILL BE GUSTY WEST TO NORTHWESTERLY WINDS
DEVELOPING AS COLD AIR POURS INTO THE AREA WITH TIGHT PRESSURE
GRADIENT AS LOW SHIFTS INTO MINNESOTA. STRONGEST WINDS LOOK TO BE
OVER SOUTHWEST NORTH DAKOTA IN THE MORNING...WITH WINDS
DIMINISHING IN THE AFTERNOON AS GRADIENT RELAXES AND COLD AIR
ADVECTION DECREASES. TEMPERATURES WILL BE SEASONABLY COOL WITH
MANY LOCATIONS AROUND 10-15 DEGREES BELOW AVERAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
A NORTHWEST FLOW ALOFT IS MAINTAINED THURSDAY NIGHT INTO
SATURDAY...THEN TRANSITIONS TO A ZONAL FLOW SUNDAY INTO WEDNESDAY. A
MORE ACTIVE PERIOD WILL EVOLVE DURING THE ZONAL FLOW PERIOD AS A
STRONG SHORTWAVE TROUGH AND ASSOCIATED POTENT COLD FRONT IS SLATED
TO SWEEP THROUGH TUESDAY INTO WEDNESDAY...WITH SEVERE WEATHER POSSIBLE.
GUSTY NORTHWEST WINDS THURSDAY EVENING WILL QUICKLY SUBSIDE AS A
SURFACE HIGH PRESSURE SLIDES ACROSS SOUTHWEST NORTH DAKOTA EARLY
THURSDAY NIGHT AND INTO CENTRAL SOUTH DAKOTA BY 12Z FRIDAY. A CLEAR
SKY...GOOD RADIATIONAL COOLING...AND DEWPOINTS IN THE UPPER 30S LOOK
REASONABLE TO SUPPORT OVERNIGHT LOWS IN THE UPPER 30S ACROSS THE
SOUTHWEST...ESPECIALLY OVER THE NORMAL COLDER LOCATIONS SUCH AS
HETTINGER. HENCE HAVE LOWERED MINIMUM TEMPERATURES INTO THE UPPER
30S UNDER THIS WEATHER PATTERN. OVERALL...A QUIET/PLEASANT WEATHER
PATTERN CONTINUES FRIDAY/SATURDAY WITH A SLOW MODERATING TREND. H85
TEMPS BEGIN TO WARM LEADING TO HIGHS INTO THE 70S SATURDAY AND
SUNDAY. THERE WILL BE A SUBTLE DRY COLD FRONTAL PASSAGE SATURDAY
AFTERNOON...HOWEVER OTHER THAN A WINDSHIFT TO THE NORTHWEST...NOT
EXPECTING MUCH OF A TEMPERATURE CHANGE.
A MORE ACTIVE WEATHER PATTERN SLOWLY BEGINS TO EMERGE SUNDAY NIGHT
AS A WEAK SHORTWAVE SLIDES THROUGH WITH WARM AIR ADVECTION PROCESSES
TAKING OVER. A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS ARE POSSIBLE
SUNDAY NIGHT INTO MONDAY MAINLY FOR THE JAMES RIVER VALLEY. THE
WARMEST DAY WILL BE MONDAY WITH HIGHS REACHING BETWEEN 75 AND 85.
THIS WILL BE FOLLOWED BY A STRONG COLD FRONT WHICH WILL APPROACH
NORTHWEST NORTH DAKOTA TUESDAY MORNING AND THEN SWEEP THROUGH
TUESDAY AFTERNOON/EVENING. A STRONG H85 BAROCLINIC ZONE SHIFTS
THROUGH TUESDAY NIGHT WITH THE 0C TO -2C ISOTHERM SETTLING INTO
CENTRAL NORTH DAKOTA WEDNESDAY. THIS TREND SETS THE STAGE FOR MUCH
COLDER AIR WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 106 AM CDT THU SEP 4 2014
SCATTERED CONVECTION THIS EVENING CONTINUES EAST ACROSS CENTRAL
NORTH DAKOTA AS A COLD FRONT MOVES THROUGH THE AREA. FLOW WILL
TURN WEST TO NORTHWEST LATE TONIGHT AND THURSDAY WITH AREAS OF
IFR-MVFR CLOUDINESS MOST LOCATIONS. STRONG NORTHWEST WINDS ON
THURSDAY WITH THE STRONGEST 20 TO 35 MPH AT KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 AM THIS MORNING TO 4 PM MDT THIS AFTERNOON
FOR NDZ031>033-040-041-043-044.
&&
$$
UPDATE...NH
SHORT TERM...JJS
LONG TERM...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1147 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1150 PM CDT WED SEP 3 2014
QUICK UPDATE TO REMOVE A FEW COUNTIES ACROSS WESTERN NORTH DAKOTA.
SURFACE COLD FRONT HAS MOVED THROUGH THE FAR WEST AND THE SEVERE
THREAT HAS DECREASED GREATLY THERE. FARTHER EAST...TWO CONVECTIVE
SYSTEMS CONTINUE TO PRODUCE SEVERE WEATHER...ONE OVER EASTERN DUNN
AND THE OTHER OVER EASTERN MCLEAN. UPDATED POPS BASED ON LATEST
RADAR AND NEAR TERM MODELS.
UPDATE ISSUED AT 916 PM CDT WED SEP 3 2014
THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA HAVE INCREASED IN
COVERAGE OVER THE PAST COUPLE HOURS. HAVE INCREASED POPS ACROSS
THE SOUTHWEST AND CENTRAL PART OF THE STATE WITH THE HRRR AND RAP
SHOWING HIGHER THUNDERSTORM CHANCES FOR THOSE LOCATIONS.
UPDATE ISSUED AT 640 PM CDT WED SEP 3 2014
ISOLATED SEVERE THUNDERSTORM CONTINUES TO TRACK EAST ACROSS
NORTHWEST NORTH DAKOTA...WITH ADDITIONAL STRONG CONVECTION OVER
NORTHEAST MONTANA. SURFACE BASED CONVECTION HAS YET TO DEVELOP
OVER WESTERN NORTH DAKOTA BUT SUCCESSIVE RUNS OF THE HRRR HAVE
INDICATED SCATTERED CONVECTION ACROSS THE SOUTHWEST AND MOVING
INTO THE SOUTH CENTRAL. LATEST RUN IS HINTING MORE AT THE
CONVECTION IN NORTHEAST MONTANA TRACKING ACROSS THE NORTHWEST AND
NORTH CENTRAL. WILL NEED TO MONITOR FOR POSSIBLE CONVECTIVE WATCH
THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHEAST MONTANA WITH
MOISTURE CONTINUING TO SLOWLY WRAP UP INTO CENTRAL NORTH DAKOTA
AHEAD OF IT. UPPER LEVEL ANALYSIS PLACES TROUGH/LOW PUSHING FORWARD
INTO EASTERN MONTANA. INITIAL WAVE EJECTING AHEAD OF THE TROUGH
CONTINUES TO PRODUCE CONVECTION OVER NORTHEAST MONTANA. FORECAST
CHALLENGES FOR TODAY INCLUDE THE SEVERE POTENTIAL LATE TODAY INTO
TONIGHT...AND THEN GUSTY WINDS ON THURSDAY.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...UPPER TROUGH WILL
CONTINUE ITS EASTWARD PUSH WITH BROAD SCALE LIFT CONTINUING TO
INCREASE FROM WEST TO EAST. MOISTURE WILL CONTINUE TO INCREASE AS
LOW SLOWLY SHIFTS TOWARDS NORTH CENTRAL SOUTH DAKOTA. INITIAL
DISCRETE STORMS THAT DEVELOP WILL ENCOUNTER INCREASING INSTABILITY
ALONG WITH IMPRESSIVE DEEP LAYER SHEAR. EXPECT INITIAL STORMS WILL
HAVE A MAINLY HAIL THREAT ALONG WITH A STRONG WIND THREAT. AS TIME
GOES ON AND STORM DEVELOPMENT WORKS EASTERLY ENCOUNTERING HIGHER
MOISTURE...THERE MAY BE A BRIEF TORNADO THREAT IF THE STORMS CAN
BE SURFACE BASED. WITH THAT SAID...THE HAIL AND WIND THREAT WILL
CONTINUE INTO THE LATE EVENING. FOCUS FOR SEVERE WILL SHIFT OVER
MAINLY CENTRAL INTO EASTERN NORTH DAKOTA OVERNIGHT AS PLUME OF
STRONG INSTABILITY REMAINS WITH STRONG THETA-E ADVECTION...WHILE
OVER THE WEST ATMOSPHERE WILL STABILIZE. STORMS SHOULD ALL BE
PUSHED OFF TO THE EAST BY SUNRISE WITH SHOWERS LINGERING.
ON THURSDAY...SOME SHOWERS WILL REMAIN PRIMARILY OVER THE NORTHERN
AND EASTERN PART OF THE STATE AS UPPER TROUGH MAKES ITS WAY EAST.
PRIMARY CONCERN WILL BE GUSTY WEST TO NORTHWESTERLY WINDS
DEVELOPING AS COLD AIR POURS INTO THE AREA WITH TIGHT PRESSURE
GRADIENT AS LOW SHIFTS INTO MINNESOTA. STRONGEST WINDS LOOK TO BE
OVER SOUTHWEST NORTH DAKOTA IN THE MORNING...WITH WINDS
DIMINISHING IN THE AFTERNOON AS GRADIENT RELAXES AND COLD AIR
ADVECTION DECREASES. TEMPERATURES WILL BE SEASONABLY COOL WITH
MANY LOCATIONS AROUND 10-15 DEGREES BELOW AVERAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM CDT WED SEP 3 2014
A NORTHWEST FLOW ALOFT IS MAINTAINED THURSDAY NIGHT INTO
SATURDAY...THEN TRANSITIONS TO A ZONAL FLOW SUNDAY INTO WEDNESDAY. A
MORE ACTIVE PERIOD WILL EVOLVE DURING THE ZONAL FLOW PERIOD AS A
STRONG SHORTWAVE TROUGH AND ASSOCIATED POTENT COLD FRONT IS SLATED
TO SWEEP THROUGH TUESDAY INTO WEDNESDAY...WITH SEVERE WEATHER POSSIBLE.
GUSTY NORTHWEST WINDS THURSDAY EVENING WILL QUICKLY SUBSIDE AS A
SURFACE HIGH PRESSURE SLIDES ACROSS SOUTHWEST NORTH DAKOTA EARLY
THURSDAY NIGHT AND INTO CENTRAL SOUTH DAKOTA BY 12Z FRIDAY. A CLEAR
SKY...GOOD RADIATIONAL COOLING...AND DEWPOINTS IN THE UPPER 30S LOOK
REASONABLE TO SUPPORT OVERNIGHT LOWS IN THE UPPER 30S ACROSS THE
SOUTHWEST...ESPECIALLY OVER THE NORMAL COLDER LOCATIONS SUCH AS
HETTINGER. HENCE HAVE LOWERED MINIMUM TEMPERATURES INTO THE UPPER
30S UNDER THIS WEATHER PATTERN. OVERALL...A QUIET/PLEASANT WEATHER
PATTERN CONTINUES FRIDAY/SATURDAY WITH A SLOW MODERATING TREND. H85
TEMPS BEGIN TO WARM LEADING TO HIGHS INTO THE 70S SATURDAY AND
SUNDAY. THERE WILL BE A SUBTLE DRY COLD FRONTAL PASSAGE SATURDAY
AFTERNOON...HOWEVER OTHER THAN A WINDSHIFT TO THE NORTHWEST...NOT
EXPECTING MUCH OF A TEMPERATURE CHANGE.
A MORE ACTIVE WEATHER PATTERN SLOWLY BEGINS TO EMERGE SUNDAY NIGHT
AS A WEAK SHORTWAVE SLIDES THROUGH WITH WARM AIR ADVECTION PROCESSES
TAKING OVER. A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS ARE POSSIBLE
SUNDAY NIGHT INTO MONDAY MAINLY FOR THE JAMES RIVER VALLEY. THE
WARMEST DAY WILL BE MONDAY WITH HIGHS REACHING BETWEEN 75 AND 85.
THIS WILL BE FOLLOWED BY A STRONG COLD FRONT WHICH WILL APPROACH
NORTHWEST NORTH DAKOTA TUESDAY MORNING AND THEN SWEEP THROUGH
TUESDAY AFTERNOON/EVENING. A STRONG H85 BAROCLINIC ZONE SHIFTS
THROUGH TUESDAY NIGHT WITH THE 0C TO -2C ISOTHERM SETTLING INTO
CENTRAL NORTH DAKOTA WEDNESDAY. THIS TREND SETS THE STAGE FOR MUCH
COLDER AIR WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 640 PM CDT WED SEP 3 2014
SCATTERED CONVECTION THIS EVENING ACROSS WESTERN AND CENTRAL NORTH
DAKOTA AS A COLD FRONT MOVES THROUGH THE AREA. FLOW WILL TURN
WEST TO NORTHWEST LATE TONIGHT AND THURSDAY WITH AREAS OF MVFR
CLOUDINESS...ESPECIALLY ACROSS THE NORTH...KISN TO KMOT. STRONG
NORTHWEST WINDS ON THURSDAY WITH THE STRONGEST 20 TO 35 MPH AT KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 6 AM TO 4 PM MDT THURSDAY FOR NDZ031>033-040-
041-043-044.
&&
$$
UPDATE...NH
SHORT TERM...JJS
LONG TERM...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1144 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1144 PM CDT WED SEP 3 2014
SEVERE STORMS CONTINUE TO APPROACH THE REGION FROM THE WEST. THE
STRONGEST STORMS ARE PROPAGATING EAST/SOUTHEAST...INTO THE STRONGER
INSTABILITY. ANTICIPATE THESE STORMS WILL CONTINUE TO PROPAGATE
TOWARD SOUTHEAST NORTH DAKOTA. HI-RES MODEL GUIDANCE (MPX
HOPWRF...HRRR) INDICATES A RELATIVELY HIGH PROBABILITY THAT THESE
STORMS WILL REMAIN SEVERE AS THEY MOVE ACROSS THE SOUTHERN FA OVER
THE NEXT SEVERAL HOURS (AND LIKEWISE A HIGHER PROBABILITY THAT A
SEVERE THUNDERSTORM WATCH COULD BE ISSUED BY 2AM). LOOKS LIKE
LARGE HAIL...AND SOME SORT OF BOWING SEGMENTS (STRONG WIND GUSTS)
WILL OCCUR.
UPDATE ISSUED AT 952 PM CDT WED SEP 3 2014
SEVERE STORMS HAVE DEVELOPED ACROSS WESTERN NORTH DAKOTA...MOSTLY
AS EXPECTED. THIS AREA OF STORMS SHOULD CONTINUE TO PROPAGATE
EASTWARD THROUGH THE OVERNIGHT HOURS. ADDITIONAL STORMS SHOULD
ALSO DEVELOP ACROSS SOUTHERN NORTH DAKOTA. GIVEN WHERE THE
STRONGEST INSTABILITY WILL BE LOCATED...THINKING THE BEST CHANCES
FOR THUNDERSTORMS (AND SEVERE THUNDERSTORMS) WILL BE ACROSS THE
SOUTHERN HALF OF THE FA. IN FACT...THE CURRENT ACTIVITY ACROSS
WESTERN NORTH DAKOTA (AT LEAST THE STRONGER REFLECTIVITY) IS
GRADUALLY SHIFTING SOUTHWARD WITH TIME. LARGE HAIL AND STRONG WIND
GUSTS (500MB JET ABOVE 50 KTS) WILL BE THE MAIN THREATS. ADJUSTED
TIMING OF POPS BASED ON LATEST TRENDS AND HI-RES MODEL
GUIDANCE...AND KEPT THE SEVERE MENTION ACROSS THE SOUTHERN FA.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 319 PM CDT WED SEP 3 2014
CONCERN REMAINS HOW FAR NORTH CONVECTION GETS INTO SOUTHEASTERN
FCST AREA LATE THIS AFTN/EVE AND HOW MUCH CONVECTION/PRECIP
DEVELOPS IN WRN ND THIS EVE AND MOVES EAST OVERNIGHT. RAP/HRRR AND
NAM12 HAVE BEEN DOING REASONABLE IN THEIR DEPICTION OF CONVECTION
IN CNTRL MN NORTH OF THE WARM FRONT. OBS INDICATE LIKELY WARM
FRONT FROM ABOUT WATERTOWN TO CANBY MN THEN TOWARD HUTCHINSON MN
THEN TO THE TWIN CITIES. IT HAS BEEN MOVING NORTHWARD. RAP SHOWS
LOW LEVEL JET FEEDING INTO BAND OF STORMS THAT HAS BEEN SLOWLY
LIFTING NORTHEAST THRU CNTRL MN TURNING A BIT MORE SOUTHWEST TO
NORTHEAST ORIENTATION AFTER 00Z AND THUS FOCUS OF PRECIP WILL
SHIFT EAST. REGIONAL RADARS SHOWING NOW SOME DEVELOPING SOUTHWEST
OF LINE INTO THE WARM SECTOR WEST OF WILMAR..THOUGH IT IS WEAK
NOW. IDEA FROM EARLIER SWOMCD IS FOR ACTIVITY TO INCREASE IN THE
AREA NORTHWEST AND WEST OF THE TWIN CITIES NEXT FEW HOURS. IT DOES
APPEAR MORE AND MORE LIKELY THAT ONLY THE FAR SOUTHEASTERN FCST
AREA WILL HAVE ANY IMPACTS FROM THESE STORMS AND THAT MOST WILL
STAY JUST SOUTHEAST OF OUR AREA. THUS TRIMMED POPS SOME BUT DID
KEEP SEVERE MENTION AT LEAST FOR NOW INTO THE EVE IN FAR
SOUTHEASTERN FCST AREA. REST OF THE AREA DRY THRU MID EVENING.
THEN WHAT HAPPENS IS IN QUESTION. RAP SHOWS A DEVELOPING LOW LEVEL
JET AND QUITE STRONG 850 THETA-E ADVECTION AND AN AREA OF
SHOWWALTERS TO -10C MOVING NORTH INTO SE ND 06Z AND JUST
AFTERWARDS. MAIN FORCING WILL BE MORE NORTHWEST TOWARD UPPER LOW
IN SOUTHEASTERN SASK. MODELS NOT EXCITED ABOUT TOO MUCH IN THIS
ELEVATED UNSTABLE LAYER AS IT MOVES INTO SE ND OVERNIGHT BUT AREA
IS IN FAVORABLE POSITION OF LOW LEVEL JET (LEFT QUAD) AND STRONG
INSTABILITY GRADIENT SO WOULDNT BE SURPRISED IF TSTMS DEVELOP
OVERNIGHT AHD OF COLD FRONT IN A MORE WIDESPREAD FASHION THAN
MODEL ADVERTISES.
ANYHOW....DID KEEP SEVERE MENTION OVERNIGHT PER DAY 1 SLIGHT RISK
OVER CNTRL INTO SE ND AND THIS CAN BE ADJUSTED AS NEEDED. IF 850
MB SHOWWALTERS AND LOW LEVEL JET ARE ACCURATE THEN WOULD BE ENOUGH
FOR SOME SEVERE HAILERS. MU CAPES IN THE 2500 J/KG RANGE IN SE ND.
LESS INSTABILITY FARTHER NORTH BUT MAYBE A BIT BETTER CHC OF A
BAND OF SHOWERS/STORMS LATE NIGHT INTO EARLY THURSDAY. PRECIP WILL
EXIT NW MN THURSDAY AFTN...THEN DRIER AND COOLER AIR MOVES IN THU
NIGHT. THOUGH SOME WRAPAROUND CLOUD COVER PSBL ESP IN NW MN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 319 PM CDT WED SEP 3 2014
HIGH PRESSURE IN CONTROL FRIDAY WITH LIKELY DIURNAL CU WITH COOLER
AIR ALOFT.
FOR FRI NIGHT INTO TUESDAY...
A NORTHWEST FLOW PATTERN ALOFT...VOID OF ANY APPRECIABLE MOISTURE
TRANSPORT INTO THE AREA...WILL KEEP A DRY AND COOL AIR MASS IN PLACE
THROUGH THE UPCOMING WEEKEND. THE UPPER AIR PATTERN BECOMES ZONAL
SUNDAY AND TURNS TO THE SOUTHWEST SUNDAY NIGHT...WITH LEE SIDE LOW
PRESSURE MOVING INTO THE PLAINS ON MONDAY. THIS WILL OPEN UP THE
GULF FOR INCREASED MOISTURE TRANSPORT INTO THE AREA AND BRING MORE
ACTIVE WEATHER FOR THE EARLY TO MIDDLE PART OF NEXT WEEK.
TEMPERATURES WILL TYPICALLY BE RIGHT AT OR SLIGHTLY COOLER THAN
SEASONAL NORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1144 PM CDT WED SEP 3 2014
SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE REGION TONIGHT.
USED THE LATEST RADAR IMAGERY AND HI-RES MODEL GUIDANCE FOR
TIMING. THIS ACTIVITY IS EXPECTED TO AFFECT EACH TAF SITE FOR AT
LEAST A BRIEF PERIOD OF TIME. THE STRONG ACTIVITY WILL BE ACROSS
SOUTHEAST NORTH DAKOTA...AND MAY AFFECT KFAR. BEHIND THIS
PRECIP...ANTICIPATE A PERIOD OF MVFR CIGS FOR A FEW HOURS.
THEN...VFR CONDITIONS AS WINDS BECOME WESTERLY (AND GUSTY).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM... RIDDLE/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS TULSA OK
1156 PM CDT WED SEP 3 2014
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD
AT ALL SITES.
&&
.PREV DISCUSSION... /ISSUED 844 PM CDT WED SEP 3 2014/
DISCUSSION...
HEAT INDICES HAVE IMPROVED AND THE WINDS HAVE BACKED OFF AS MIXING
CEASES WITH THE SETTING OF THE GIANT ENERGY BALL. A LEE TROUGH
OVER THE HIGH PLAINS WILL KEEP SOME SOUTH WIND GOING ALL
NIGHT...ESPECIALLY AT TUL...SO LOWS WILL BE MILD ACROSS ERN OK AND
W CNTRL AR WHERE TERRAIN EFFECTS HELP TO MAINTAIN AN EAST WIND.
RIDGING ALOFT WILL MAINTAIN DRY CONDITIONS UNTIL A FRONT ARRIVES
LATE FRIDAY.
LACY
PREV DISCUSSION... /ISSUED 604 PM CDT WED SEP 3 2014/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD
AT ALL SITES.
PREV DISCUSSION... /ISSUED 353 PM CDT WED SEP 3 2014/
DISCUSSION...
WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH
PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME
SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE
THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP
AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS
EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA
FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE
CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING
CONDITIONS.
HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL
CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED
TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE
U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD
THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS
THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY
AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS
AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH
SOUTHWESTERLY WINDS.
THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY
NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND
THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY
NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH
THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE
OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE
EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK.
SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR
THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST
TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND
ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD
FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED
TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS
FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE
MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE
FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT
WEEK.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...23
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 AM CDT THU SEP 4 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 326 AM CDT THU SEP 4 2014
SURFACE MAP AS OF 3 AM THIS MORNING HAD A DEEP 996MB LOW OVER
EASTERN SD WITH A WARM FRONT EXTENDING ACROSS SOUTHERN MN AND INTO
SOUTHWEST WI. CURRENTLY WATCHING ONE CLUSTER OF STRONG THUNDERSTORMS
DEPARTING THE AREA INTO NORTHEAST WI. WITHIN THE LAST 1/2 HOUR...A
CLUSTER OF SHOWERS AND THUNDERSTORMS POPPED UP OVER FAR NORTHEAST
IA/SOUTHWEST WI. FURTHER ANALYSIS SHOWING THESE SHOWERS AND STORMS
FORMING IN RESPONSE TO A NOSE OF STRONG 850MB MOISTURE TRANSPORT
WORKING NORTHEAST ACROSS IA...AND OCCURRING ABOVE A VERY STRONG 700-
750MB CAP OF 14C PER THE RAP BUFKIT AT BLUE RIVER WI. OTHERWISE...
TEMPERATURES ACROSS THE AREA EARLY THIS MORNING WERE IN THE 60S
ACROSS NORTH CENTRAL WI...AND IN THE 70S ELSEWHERE ACROSS THE ARX
FORECAST AREA.
WARM FRONT MAKES A PUSH NORTHEAST THROUGH THE REST OF THE AREA THIS
MORNING. THINKING THOSE SHOWERS/STORMS WILL SHOVE OUT OF THE AREA AS
CAP STRENGTHENS IN WARM SECTOR. WILL BE WATCHING AN MCS OVER ND
MAKING ITS WAY EAST-SOUTHEAST...WHICH COULD CLIP CLARK AND TAYLOR
COUNTIES AS IT MAKES ITS WAY ACROSS FAR NORTHERN WI/UPPER MI. MAY
HAVE TO ADJUST POPS ACCORDINGLY.
OTHERWISE...STRONG WARM AIR ADVECTION WILL TAKE PLACE ACROSS THE
AREA WITH STRENGTHENING 700-750MB CAP. THIS SHOULD HOLD OFF ANY
FURTHER CONVECTION AND PUSH TEMPERATURES WELL INTO THE 80S...TO A
FEW LOWER 90S ALONG/SOUTH OF I-90. DEW POINTS WILL ALSO BE
INCREASING INTO THE LOWER 70S THROUGH THE DAY...PRODUCING VERY
WARM/MUGGY/UNCOMFORTABLE CONDITIONS. HEAT INDICES FOR THE MOST PART
LOOK TO BE IN THE 90-100 RANGE...BUT COULD SEE A FEW HOURS OF 100-
105 IN A FEW SPOTS IN THE MISSISSIPPI/WISCONSIN RIVER VALLEYS. NOT
THINKING A HEAT ADVISORY WILL BE NEEDED AT THIS POINT DUE TO THE
BRIEF TOUCH IN THE CRITERIA RANGE. WILL HIT IT HARD WITH OUR OTHER
PRODUCTS.
CAP HOLDS STRONG INTO THE AFTERNOON HOURS AS A COLD FRONT PUSHES
SOUTHEASTWARD INTO NORTHERN WI/SOUTH CENTRAL MN. MODELS AT ODDS AT
HANDLING CONVECTION OR LACK THEREOF WHICH HEDGES ON STRENGTH OF
CAP...WHICH IS VERY STRONG FOR THIS TIME OF YEAR. GFS/ECMWF/CANADIAN
DETERMINISTIC MODELS ALL HOLD OFF DEVELOPING CONVECTION THROUGH 7PM.
NAM IS A BIT MORE GUNG-HO FIRING ALONG THE FRONT BASICALLY NORTH OF
I-94 BETWEEN 4-7PM. NMM/ARW WRF MODELS SIDE WITH THE NAM. REASON
BEING... BUFKIT SOUNDINGS REVEAL POSSIBLY SOME ELEVATED CONVECTION
BURBLING ABOVE THE CAP AS MID-LEVEL COOLING/STEEPENING LAPSE RATES
TAKE PLACE WITH INCOMING MID-LEVEL TROUGH. THIS WOULD COMPROMISE THE
CAP AND LET SURFACE BASED/DEEP CONVECTION RELEASE ALONG THE FRONT.
WILL HAVE TO KEEP AN EYE ON THIS FOR SEVERE WIND/HAIL POTENTIAL AS 0-
3KM BULK SHEAR IS PLENTIFUL IN THE 30-40KT RANGE ALONG WITH MUCAPE
IN THE 3000-4000J/KG RANGE.
THE COLD FRONT CONTINUES TO PUSH SOUTHEAST THROUGH THE AREA FRIDAY
NIGHT FOR CONTINUED THUNDERSTORM CHANCES. SOME OF THESE STORMS COULD
BE REMAIN SEVERE AT LEAST INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU SEP 4 2014
WITH THE COLD FRONT PUSHED INTO NORTHERN IL BY FRIDAY MORNING...
NORTHWEST WINDS WILL DRAW DRIER/COOLER AIR OVER THE FORECAST AREA.
EXPECTING FAIRLY BREEZY NORTHWEST WINDS IN THE 15-25MPH RANGE WITH
HIGHS ONLY TOPPING OFF IN THE UPPER 60S TO TO LOWER 70S.
MORE EARLY FALL-LIKE CONDITIONS ARE THEN EXPECTED INTO THE WEEKEND
AS CANADIAN HIGH PRESSURE DOMINATES THE CENTRAL CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. LOOK FOR MOSTLY CLEAR SKIES
THROUGH SUNDAY WITH HIGHS SATURDAY AND SUNDAY IN THE 70S AND
OVERNIGHT LOWS IN THE 40S TO LOWER 50S.
FOR MONDAY THROUGH WEDNESDAY...DEEPENING CYCLONIC FLOW OVER CANADA
AND NORTHERN CONUS WILL DRIVE A COUPLE TROUGHS THROUGH THE REGION FOR
A PERIOD OF UNSETTLED WEATHER WITH ON/OFF SHOWER AND THUNDERSTORM
CHANCES. TEMPERATURES ARE EXPECTED TO BE AT OR A FEW DEGREES BELOW
NORMAL WITH HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1212 AM CDT THU SEP 4 2014
SHOWERS AND STORMS REMAIN NORTHEAST OF THE TAF SITES EARLY THIS
MORNING...NORTH OF A WARM FRONT SITUATED NEAR I-94.HOWEVER...
THERE CONTINUE TO BE SIGNS FOR SHOWERS AND STORMS TO POP UP OVER
SOUTHWEST WI BETWEEN 09-11Z AND PROGRESS EASTWARD...POSSIBLY
IMPACTING LSE. THEREFORE...HAVE ADJUSTED THE TAF TO PIN DOWN THIS
PERIOD AS THE MOST LIKELY TIME FRAME. VISIBILITIES AND CEILINGS
COULD GO BRIEFLY DOWN TO MVFR WITH THIS ACTIVITY. CEILINGS BECOME
THE NEXT CONCERN WITH SOME MODELS STILL WANTING TO DEVELOP
IFR/MVFR STRATUS OVER THE TAF SITES. UNCERTAINTY STILL REMAINS
WHETHER THIS WILL HAPPEN WITH THE AIR STAYING MIXED ON A BREEZY
SOUTH WIND...THEREFORE...HAVE LEFT THE SCATTERED CEILINGS IN THE
TAFS. MONITORING FOR LOW STRATUS WILL BE REQUIRED. ANY STRATUS
SHOULD MIX OUT QUICKLY IN THE MORNING WITH DAYTIME HEATING...
RESULTING IN VFR CONDITIONS FOR THE AFTERNOON. SOUTHWESTERLY GUSTS
OF 20-25 KT SEEM LIKELY FOR THE AFTERNOON TOO. A COLD FRONT THEN
MOVES THROUGH THE TAF SITES DURING THE EVENING. QUESTIONS REMAIN
WHETHER THE FRONT CAN INITIATE STORMS...THEREFORE...ONLY HAVE A
VCTS MENTION IN THE TAFS FOR NOW. WINDS LOOK TO SWING AROUND TO
THE WEST WITH SPEEDS DECREASING AS THE FRONT PASSES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
228 AM CDT THU SEP 4 2014
.SHORT TERM...
TODAY...FORECAST CONFIDENCE IS MEDIUM.
THE SECONDARY CONVECTIVE DEVELOPMENT...TIED WITH THE H8 WARM FRONT
ON THE NOSE OF THE LOW LEVEL JET LEANING INTO THE AREA...IS
EXPANDING QUICKLY ACROSS SOUTHWEST WI AT THE TIME OF THIS WRITING.
FOR SOME REASON THE HRRR HAS DECIDED TO DUMP THIS DEVELOPMENT AND
WENT DRY WITH THE 04 AND 05Z UPDATES. WELL...THAT/S NOT GOING TO
WORK OUT.
SATELLITE IMAGERY IS SHOWING A LOWER MID DECK EXPANDING QUICKLY
UPSTREAM...HIGHLIGHTING THE CONVERGENCE OF WARM AND MOIST AIR ON THE
NOSE OF THAT H8 JET. MOST OF THE MODELS SHOW THIS DEVELOPMENT
OCCURRING EARLY THIS MORNING...EXITING BY MID TO LATE MORNING.
ISOLATED SEVERE STORMS ARE POSSIBLE WITH WIND AND HAIL THE MAIN
THREAT. THE RAIN WOULD BE HEAVY AND URBAN AND SMALL STREAM FLOODING
IS POSIBLE IF ANY STORMS TURN AWAY FROM THE FASTER MEAN FLOW.
ONCE THE STORMS MOVE OUT...WE GET INTO A VERY IMPRESSIVE THERMAL
RIDGE AHEAD OF AN APPROACHING COLD FRONT. 925MB TEMPS CLIMB TO AN
IMPRESSIVE 25-27C...IF WE GET ENOUGH SUNSHINE WE COULD SEE MANY
AREAS HIT THE 90 MARK. I/M COMFORTABLE KEEPING WHAT WE HAVE IN THE
FORECAST...WHICH IS ABOVE MOST GUIDANCE VALUES RIGHT NOW. THE
AIRMASS OVER US TODAY WILL BE VERY HUMID WITH DEW POINTS REACHING
THE LOWER 70S. THE HEAT INDEX WILL BE IN THE MID TO UPPER 90S.
THANKFULLY THIS IS SHORT LIVED AS THE COLD FRONT COMING THROUGH
TONIGHT WILL BRING MUCH COOLER TEMPS ON FRIDAY.
TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
A STRONG COLD FRONT WILL PUSH THROUGH THE AREA OVERNIGHT. IT/S A
RATHER LATE SHOW FOR SOUTHERN WISCONSIN AS THE FRONT DOESN/T REACH
MADISON UNTIL ABOUT 6 AM FRIDAY AND MILWAUKEE ABOUT 9 AM. THE
INITIAL DEVELOPMENT SHOULD OCCUR OVER ECNTRL MN AND WCNTRL WI THEN
EXPAND AND ORGANIZE ALONG THE FRONT WITH TIME...HEADING SOUTHEAST
INTO SOUTHERN WISCONSIN OVERNIGHT. THE AIRMASS WILL BE VERY MOIST
AHEAD OF THE FRONT...BUT THE LATE TIMING WILL BEGIN TO LIMIT
INSTABILITY OVER TIME. IN ADDITION...THE LOW LEVEL JET FOCUSES WELL
EAST OF WISCONSIN BY THE TIME THE FRONT ARRIVES. WOULD EXPECT A FEW
STORMS TO BECOME SEVERE NORTHWEST OF OUR FORECAST AREA...WHERE
STORMS INTITIATE...THEN AS THEY DRIFT SOUTH INTO THE FORECAST
AREA...THE INTENSITY WILL GRADUALLY DIMINISH. SPC HAS US IN A
SLIGHT RISK OF SEVERE STORMS NORTH OF A PORT WASHINGTON TO MADISON
TO DODGEVILLE LINE. THE FAR SOUTH WOULD STRUGGLE TO SEE SEVERE GIVEN
THE TIMING. THIS LOOKS VERY REASONABLE. THE MAIN THREAT WILL BE WIND
AND HAIL.
FRIDAY AND FRIDAY NIGHT...FORECAST CONFIDENCE MEDIUM.
THE SURFACE TO 850MB COLD FRONT WILL BE REACHING FAR SOUTHEAST WI
AROUND 12Z...WHICH IS LATER THAN THE PAST SEVERAL MODEL RUNS.
MEANWHILE... A STRONG MID LEVEL SHORTWAVE TROUGH WILL BE SLIDING
ACROSS THE UPPER MIDWEST. AHEAD OF THIS TROUGH... THERE WILL BE WEAK
SHORTWAVE ACTIVITY AND ALSO RISING MOTION IN THE RIGHT ENTRANCE
REGION OF AN UPPER JET. THE AREA JUST BEHIND THE SURFACE COLD FRONT
AND AHEAD OF THE UPPER TROUGH WILL LINE UP OVER SOUTHEAST WI DURING
THE DAY FRIDAY AND KEEP THE POSSIBILITY OF SHOWERS AND ISOLATED
THUNDERSTORMS GOING. THE LIMITING FACTOR FOR PRECIP IS A DRY LAYER
FROM 5 TO 10 KFT.
THE MODELS ARE MIXED ABOUT WHERE SHOWERS AND THUNDERSTORMS WILL
TRACK FRIDAY AFTERNOON. MOST SUGGEST THE MAIN FORCING AND PRECIP
WILL BE SOUTH OF THE WI/IL BORDER. THUS...WILL CONTINUE THE
DIMINISHING TREND FOR POPS ON FRIDAY AFTERNOON AND EVENING.
THERE SHOULD BE PLENTY OF CLOUDS OVER SOUTHERN WI ON FRIDAY.
THAT AND THE COLD AIR ADVECTION WILL LIMIT HIGHS TO THE MID 70S.
THE MID LEVEL SHORTWAVE TROUGH WILL EXIT SOUTHEAST WI BY AROUND
MIDNIGHT FRIDAY NIGHT. THIS WILL USHER MUCH DRIER AND COOLER AIR
INTO SOUTHERN WI WHICH WILL HANG AROUND THROUGH THE WHOLE WEEKEND
AND MONDAY.
.LONG TERM...
SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE HIGH.
PLAN ON A QUIET STRETCH OF WEATHER FOR THE WEEKEND WITH LOW HUMIDITY
AND COOLER TEMPERATURES. HIGHS WILL BE IN THE LOWER TO MID 70S WITH
PLENTY OF SUNSHINE. LOWS WILL DROP DOWN INTO THE LOWER 50S...WITH
SATURDAY NIGHT LOOKING LIKE THE COOLEST. DEWPOINT DEPRESSIONS SHOULD
BE FAIRLY LOW WITH LIGHT WINDS...SO PATCHY FOG LOOKS POSSIBLE.
MONDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM.
THE ECMWF AND GFS ARE NOW OUT OF PHASE FOR THE NEXT WARM AIR ROUND
OF THUNDERSTORMS IMPACTING SOUTHERN WI MONDAY NIGHT AND TUESDAY.
THE GFS IS ROUGHLY 6 HOURS SLOWER WITH THE PRECIP AND HAS A
WEAKER- LOOKING SHORTWAVE TROUGH DUE TO THE EARLIER ARRIVAL OF AN
UPPER JET STREAK.
THEN THE TWO MODELS ARE BACK INTO GENERAL AGREEMENT ABOUT A BACK
DOOR COLD FRONT DROPPING DOWN THE LAKE INTO SOUTHERN WI LATE TUESDAY
NIGHT. THERE IS NOT MUCH FORCING FOR PRECIP...SO LOW CLOUDS AND
MAYBE A FEW SPRINKLES WOULD BE POSSIBLE THROUGH WED MORNING. THEN
THERE SHOULD BE A PERIOD OF QUIET WEATHER WITH EASTERLY WINDS OVER
SOUTHERN WI THROUGH WED NIGHT. THEREFORE...WENT WITH A LOWERING
TREND FOR POPS AND THUNDER IN THE FORECAST.
ANOTHER ROUND OF SHOWERS AND STORMS ARE POSSIBLE FOR SOUTHERN WI AS
A MID LEVEL TROUGH SLIDES FROM THE NORTHERN PLAINS TO THE GREAT
LAKES REGION LATE IN THE WEEK...THURSDAY THROUGH FRIDAY NIGHT.
THERE ARE STILL PLENTY OF MODEL DIFFERENCES THAT WILL NEED TO BE
IRONED OUT BEFORE DECIDING THE EXTENT OF THUNDER.
&&
.AVIATION/12Z TAFS/...
IN GENERAL...EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD.
HOWEVER...THERE ARE A COUPLE OF OPPORTUNITIES FOR LOWER CONDITIONS.
WE SHOULD SEE AT LEAST SCATTERED CONVECTION THIS MORNING AS A WARM
FRONT MOVES THROUGH. CONDITIONS WOULD DETERIORATE TO MVFR OR EVEN
IFR LEVELS IN ANY STRONGER STORMS. THINGS SHOULD CLEAR OUT BY LATE
MORNING AS HOT AIR ARRIVES AHEAD OF AN APPROACHING COLD FRONT. LOOK
FOR RATHER BREEZY CONDITIONS WITH A SOUTH TO SOUTHWEST WIND LATER
THIS MORNING AND AFTERNOON. THE COLD FRONT ARRIVES LATE
TONIGHT...REACHING MADISON AROUND 12Z FRIDAY AND KMKE/KUES/KENW
AROUND 15-16Z FRI. IT LOOKS LIKE THERE COULD BE A SHORT PERIOD OF
MVFR CIGS/VSBYS IN THE COLD AIR ADVECTION IN THE IMMEDIATE WAKE OF
THE FRONT. THUNDERSTORMS ARE ALSO POSSIBLE WITH THE FRONTAL PASSAGE
LATE TONIGHT.
&&
.MARINE...
SOUTH TO SOUTHWEST WINDS TODAY WILL GUST TO AROUND 25 KNOTS...SO A
SMALL CRAFT ADVISORY IS IN EFFECT FROM 10 AM TO 10 PM TODAY. WAVES
WILL INCREASE TO 3 TO 5 FEET THURSDAY...THE HIGHEST WAVES IN THE
NORTH.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM CDT THIS
EVENING FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
FRIDAY THROUGH WEDNESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1212 AM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 1212 AM CDT THU SEP 4 2014
SHORTWAVE ON WATER VAPOR AND RADAR IMAGERY PROGRESSING ACROSS
NORTHEAST WI AND WESTERN UPPER MI CURRENTLY CONTINUES TO BRING
SHOWERS AND STORMS TO TAYLOR AND CLARK COUNTIES. HOWEVER...THESE
STORMS ARE A LOT WEAKER NOW COMPARED TO A COUPLE HOURS
AGO...DESPITE A DECENT INSTABILITY FEED INTO THEM ON A LOW LEVEL
JET. BELIEVE PART OF THIS REASON IS THAT THE NOSE OF THE 925-850MB
MOISTURE TRANSPORT ASSOCIATED WITH THE SHORTWAVE HAS NOW SHIFTED
OFF TO NORTHEAST WI AND EASTERN UPPER MI. THEREFORE...THE SEVERE
THUNDERSTORM WATCH WAS CANCELLED ABOUT AN HOUR AGO. THE STORMS
ARE STILL DUMPING HEAVY RAIN...ENOUGH THAT CONDITIONS WERE GETTING
CLOSE OVER NORTHERN CLARK COUNTY FOR A FLOOD RELATED PRODUCT.
HOWEVER...THOSE STORMS ARE DROPPING SOUTHEAST AND DIMINISHING FROM
THE WEST...WHICH BOTH ARE HELPING TO PRECLUDE THE NEED FOR ANY
FLOOD ADVISORY OR WARNING.
CONDITIONS STILL LOOK FAVORABLE FOR SHOWERS AND STORMS TO POP UP
OVER SOUTHWEST WISCONSIN TOWARDS 09-10Z. THESE WILL FORM FROM
ANOTHER SURGE OF 850MB MOISTURE TRANSPORT COMING UP FROM IOWA
AHEAD OF A SHORTWAVE IN CENTRAL IOWA. IN FACT...THIS SHORTWAVE HAS
HELPED MAINTAIN A CLUSTER OF STORMS NOW TRACKING EAST OF DES
MOINES. STILL ANTICIPATING HEAVY RAIN TO BE THE MAIN CONCERN WITH
ANY STORMS THAT POP UP...THOUGH THEY TOO SHOULD BE PROGRESSIVE TO
THE EAST TO LIMIT ANY FLOOD THREAT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST
TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS
SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS
FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW
POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER
CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A
GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM
ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS
DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND
MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH
MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT
THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT
NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE
MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN
ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS
BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH-
CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL
DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD
POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING
WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN
ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND
PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE
EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR
TRAINING CELLS.
FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW
THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF
STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST
IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES
INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER
AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL
MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE
STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO
ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH
ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT
AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN
THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL
INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY
FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES.
ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE
CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR
FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE
FORECAST TOWARD IT.
ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB
TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP
OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS
CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE
THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL
MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE
LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C
TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K
RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR
WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY
EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN
THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION
CHANCES IN THE 20 TO 50 PERCENT RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A
STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST
AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE
CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS
GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME
QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW
WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM
SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY...
THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN
ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF
LARGE HAIL.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH
THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM
WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR.
FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE
THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY
TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE
TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH
INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY
SEVERE WEATHER AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1212 AM CDT THU SEP 4 2014
SHOWERS AND STORMS REMAIN NORTHEAST OF THE TAF SITES EARLY THIS
MORNING...NORTH OF A WARM FRONT SITUATED NEAR I-94.HOWEVER...
THERE CONTINUE TO BE SIGNS FOR SHOWERS AND STORMS TO POP UP OVER
SOUTHWEST WI BETWEEN 09-11Z AND PROGRESS EASTWARD...POSSIBLY
IMPACTING LSE. THEREFORE...HAVE ADJUSTED THE TAF TO PIN DOWN THIS
PERIOD AS THE MOST LIKELY TIME FRAME. VISIBILITIES AND CEILINGS
COULD GO BRIEFLY DOWN TO MVFR WITH THIS ACTIVITY. CEILINGS BECOME
THE NEXT CONCERN WITH SOME MODELS STILL WANTING TO DEVELOP
IFR/MVFR STRATUS OVER THE TAF SITES. UNCERTAINTY STILL REMAINS
WHETHER THIS WILL HAPPEN WITH THE AIR STAYING MIXED ON A BREEZY
SOUTH WIND...THEREFORE...HAVE LEFT THE SCATTERED CEILINGS IN THE
TAFS. MONITORING FOR LOW STRATUS WILL BE REQUIRED. ANY STRATUS
SHOULD MIX OUT QUICKLY IN THE MORNING WITH DAYTIME HEATING...
RESULTING IN VFR CONDITIONS FOR THE AFTERNOON. SOUTHWESTERLY GUSTS
OF 20-25 KT SEEM LIKELY FOR THE AFTERNOON TOO. A COLD FRONT THEN
MOVES THROUGH THE TAF SITES DURING THE EVENING. QUESTIONS REMAIN
WHETHER THE FRONT CAN INITIATE STORMS...THEREFORE...ONLY HAVE A
VCTS MENTION IN THE TAFS FOR NOW. WINDS LOOK TO SWING AROUND TO
THE WEST WITH SPEEDS DECREASING AS THE FRONT PASSES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
845 AM MST THU SEP 4 2014
&&
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL REMAIN MORE ISOLATED OVER THE HIGHER TERRAIN
THROUGH FRIDAY...BUT SHOULD BECOME MORE PERIODIC AND WIDESPREAD BY
THE END OF THE WEEKEND AND EARLY NEXT WEEK. HEAVY RAINFALL AND
LOCALIZED FLOODING WILL BE THE PRIMARY THREATS WITH THESE STORMS
LATE IN THE WEEKEND...WITH CLEARING ONLY SLOWLY OCCURRING NEXT WEEK.
&&
.DISCUSSION...
LATEST SATELLITE AND RADAR IMAGERY IS NOW SHOWING A CLEARING TREND
ACROSS SOUTH-CENTRAL ARIZONA AS THE WEAK TROUGH THAT TRIGGERED
THUNDERSTORM ACTIVITY ACROSS NORTHWEST MARICOPA COUNTY MOVES
NORTHWARD INTO NORTHERN YAVAPAI AND COCONINO COUNTIES...WITH WEAK
SUBSIDENCE BEHIND THIS FEATURE CLEARING THE SKIES ACROSS OUR CWA.
BASED ON THE LATEST HRRR AND RUC13 MODEL OUTPUT...HAVE DECIDED TO
REDUCE POPS IN THE 18Z-00Z TIME FRAME ACROSS WESTERN MARICOPA
COUNTY...BUT LEFT ELEVATED POPS ALONE ACROSS EXTREME EASTERN
MARICOPA COUNTY AND POINTS EAST...SINCE THESE MODELS ARE SILL
SHOWING SOME SPRINKLES/LIGHT SHOWERS DEVELOPING ACROSS THAT REGION.
OTHERWISE...WILL BE LEAVING INHERITED GRIDS ALONE FOR NOW.
&&
.PREVIOUS DISCUSSION...
LATEST RAP STREAMLINE ANALYSIS SHOWS A WEAK TROUGH ACROSS SOUTHERN
CA WITH DEEPER MOISTURE LIFTING NORTHWARD ACROSS AZ IN A
SOUTHWESTERLY FLOW. ISOLATED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED EARLY THIS MORNING...MAINLY ACROSS NORTHWESTERN PORTIONS
OF MARICOPA COUNTY...PRODUCING BRIEF HEAVY RAIN. GIVEN THE LACK OF
ELEVATED CAPE...THE ACTIVITY IS PRESUMABLY BEING AIDED BY
VORTICITY-FORCED ASCENT AHEAD OF THE AFOREMENTIONED TROUGH AND A
GRAVITY WAVE PROPAGATING NORTHWESTWARD FROM EARLIER CONVECTION
ACROSS SOUTHERN AZ. LATEST HRRR HAS ASSIMILATED THIS ACTIVITY AND
SUGGESTS IT WILL TREK INTO CENTRAL AND NORTHERN AZ AS IT IS ABSORBED
INTO THE DEEPER SOUTHWESTERLY FLOW LATER THIS MORNING.
THEREAFTER...GLOBAL AND CONVECTIVE-ALLOWING MODELS INDICATE A WIDE
RANGE OF POSSIBILITIES. CONCEPTUALLY...STRONGEST ASCENT WILL SPREAD
NORTH AND EASTWARD INTO THE HIGHER ELEVATIONS OF EASTERN AZ.
HOWEVER...STEADILY INCREASING PWATS AS FAR WEST AS SOUTHWESTERN
MARICOPA COUNTY WARRANT A SLIGHT CHANCE OF PRECIPITATION THROUGHOUT
THE DAY. GIVEN THE INCREASING MOISTURE AND DECREASING
THICKNESSES...TEMPERATURES WILL BE A FEW DEGREES COOLER THAN THOSE
OBSERVED WEDNESDAY.
HIGH PRESSURE WILL BRIEFLY REBUILD ACROSS THE FORECAST AREA
FRIDAY...RESULTING IN A WEAKER WESTERLY FLOW.
CONSEQUENTLY...INCREASE IN PWATS WILL TAKE A BRIEF HIATUS ACROSS THE
LOWER DESERTS AND CONVECTION WILL BE MOST CONCENTRATED ACROSS
SOUTHERN AND EASTERN AZ.
MODELS REMAIN CONSISTENT THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK WITH THEIR DEPICTION OF DEEPER TROPICAL MOISTURE LIFTING
NORTHWARD OUT OF MEXICO AND INTO THE DESERT SOUTHWEST. ALTHOUGH
NEARBY HURRICANE NORBERT WILL LIKELY NOT HAVE A DIRECT IMPACT ON OUR
WEATHER...ITS INFLUENCE WILL BE FAVORABLE FOR PRECIPITATION WITHIN
THE REGION. OFFICIAL NHC FORECASTS INDICATE THAT THE WEAKENING TC
WILL MORE OR LESS TRACK PARALLEL TO THE BAJA PENINSULA...SUGGESTING
THAT MOISTURE TRANSPORT WILL BE MAXIMIZED ACROSS PORTIONS OF AZ.
MODELS SUGGEST THAT PWATS WILL APPROACH 2 INCHES
SUNDAY...INCREASING THE LIKELIHOOD OF HEAVY RAIN AND FLOODING.
RECENT TRENDS IN THE ECWMF ALSO SUGGEST A SOMEWHAT SLOWER ONSET OF
THE DEEPER MOISTURE...WITH THE BEST CHANCE FOR PRECIPITATION
OCCURRING SUNDAY AND MONDAY. HOWEVER...THE GFS PAINTS A DIFFERENT
PICTURE WITH THE DEVELOPMENT OF A DRY SLOT MONDAY BETWEEN THE
REMNANTS OF NORBERT AND DEEPER MOISTURE TO THE EAST. BOTTOM LINE IS
THAT CONSIDERABLE UNCERTAINTY REMAINS...THOUGH IT APPEARS MORE
LIKELY THAT A WIDESPREAD 1 TO 2 INCHES OF RAIN CAN BE EXPECTED FROM
MARICOPA COUNTY EASTWARD THROUGH TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
ISOLATED SHOWERS/THUNDERSTORMS EXPECTED ACROSS SOUTH-CENTRAL ARIZONA
THIS MORNING...MAINLY ACROSS HIGHER TERRAIN AREAS TO THE NORTH AND
EAST OF PHOENIX...WITH SCT-BKN CLOUD DECKS AOA 10KFT. WINDS WILL
CONTINUE TO FAVOR EAST-SOUTHEAST GENERALLY 10KT OR LESS...AND MAY
SWITCH TO SOUTHWEST BRIEFLY FOR A COUPLE HOURS IF THERE IS
SUFFICIENT CLEARING OF MID-LEVEL CLOUD DECKS LATE THIS AFTERNOON.
ISOLATED SHOWER/THUNDERSTORMS ACTIVITY ENCROACHES ONCE AGAIN NEAR
TERMINALS THIS EVENING...BUT UNCERTAINTY IN TIMING/COVERAGE
WARRANTS LEAVING ANY MENTION OF WEATHER OUT OF THE TAFS AT THIS
TIME.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE TODAY...WITH MOSTLY
CLEAR SKIES AND JUST A FEW-SCT MID LEVEL CUMULUS. WINDS SHOULD
CONTINUE TO FAVOR SOUTH-SOUTHEAST GENERALLY 10KT OR LESS...EXCEPT
ALONG THE LOWER COLORADO RIVER VALLEY/NEAR KBLH WHERE GUSTS UP TO
25KT WILL ACCOMPANY ADDITIONAL MOISTURE SURGE AFTER 06Z FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
MONSOON MOISTURE WILL CONTINUE TO INCREASE AND SPREAD NORTH AND WEST
REACHING THE LOWER DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA BY SATURDAY. STORM CHANCES WILL CONTINUE THROUGH TUESDAY
BEFORE TRENDING DOWNWARD LATE IN THE PERIOD. HUMIDITIES WILL REMAIN
ELEVATED DURING THE PERIOD...WHILE TEMPERATURES TREND DOWNWARD.
WINDS WILL FOLLOW FAMILIAR SUMMERTIME SLOPE-VALLEY PATTERNS BUT WITH
SIGNIFICANT DISRUPTIONS DUE TO THUNDERSTORM ACTIVITY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/HIRSCH
AVIATION...MEYERS
FIRE WEATHER...AJ/MEYERS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
513 AM MST THU SEP 4 2014
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL REMAIN MORE ISOLATED OVER THE HIGHER TERRAIN
THROUGH FRIDAY...BUT SHOULD BECOME MORE PERIODIC AND WIDESPREAD BY
THE END OF THE WEEKEND AND EARLY NEXT WEEK. HEAVY RAINFALL AND
LOCALIZED FLOODING WILL BE THE PRIMARY THREATS WITH THESE STORMS
LATE IN THE WEEKEND...WITH CLEARING ONLY SLOWLY OCCURRING NEXT WEEK.
&&
.DISCUSSION...
LATEST RAP STREAMLINE ANALYSIS SHOWS A WEAK TROUGH ACROSS SOUTHERN
CA WITH DEEPER MOISTURE LIFTING NORTHWARD ACROSS AZ IN A
SOUTHWESTERLY FLOW. ISOLATED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED EARLY THIS MORNING...MAINLY ACROSS NORTHWESTERN PORTIONS
OF MARICOPA COUNTY...PRODUCING BRIEF HEAVY RAIN. GIVEN THE LACK OF
ELEVATED CAPE...THE ACTIVITY IS PRESUMABLY BEING AIDED BY
VORTICITY-FORCED ASCENT AHEAD OF THE AFOREMENTIONED TROUGH AND A
GRAVITY WAVE PROPAGATING NORTHWESTWARD FROM EARLIER CONVECTION
ACROSS SOUTHERN AZ. LATEST HRRR HAS ASSIMILATED THIS ACTIVITY AND
SUGGESTS IT WILL TREK INTO CENTRAL AND NORTHERN AZ AS IT IS ABSORBED
INTO THE DEEPER SOUTHWESTERLY FLOW LATER THIS MORNING.
THEREAFTER...GLOBAL AND CONVECTIVE-ALLOWING MODELS INDICATE A WIDE
RANGE OF POSSIBILITIES. CONCEPTUALLY...STRONGEST ASCENT WILL SPREAD
NORTH AND EASTWARD INTO THE HIGHER ELEVATIONS OF EASTERN AZ.
HOWEVER...STEADILY INCREASING PWATS AS FAR WEST AS SOUTHWESTERN
MARICOPA COUNTY WARRANT A SLIGHT CHANCE OF PRECIPITATION THROUGHOUT
THE DAY. GIVEN THE INCREASING MOISTURE AND DECREASING
THICKNESSES...TEMPERATURES WILL BE A FEW DEGREES COOLER THAN THOSE
OBSERVED WEDNESDAY.
HIGH PRESSURE WILL BRIEFLY REBUILD ACROSS THE FORECAST AREA
FRIDAY...RESULTING IN A WEAKER WESTERLY FLOW.
CONSEQUENTLY...INCREASE IN PWATS WILL TAKE A BRIEF HIATUS ACROSS THE
LOWER DESERTS AND CONVECTION WILL BE MOST CONCENTRATED ACROSS
SOUTHERN AND EASTERN AZ.
MODELS REMAIN CONSISTENT THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK WITH THEIR DEPICTION OF DEEPER TROPICAL MOISTURE LIFTING
NORTHWARD OUT OF MEXICO AND INTO THE DESERT SOUTHWEST. ALTHOUGH
NEARBY HURRICANE NORBERT WILL LIKELY NOT HAVE A DIRECT IMPACT ON OUR
WEATHER...ITS INFLUENCE WILL BE FAVORABLE FOR PRECIPITATION WITHIN
THE REGION. OFFICIAL NHC FORECASTS INDICATE THAT THE WEAKENING TC
WILL MORE OR LESS TRACK PARALLEL TO THE BAJA PENINSULA...SUGGESTING
THAT MOISTURE TRANSPORT WILL BE MAXIMIZED ACROSS PORTIONS OF AZ.
MODELS SUGGEST THAT PWATS WILL APPROACH 2 INCHES
SUNDAY...INCREASING THE LIKELIHOOD OF HEAVY RAIN AND FLOODING.
RECENT TRENDS IN THE ECWMF ALSO SUGGEST A SOMEWHAT SLOWER ONSET OF
THE DEEPER MOISTURE...WITH THE BEST CHANCE FOR PRECIPITATION
OCCURRING SUNDAY AND MONDAY. HOWEVER...THE GFS PAINTS A DIFFERENT
PICTURE WITH THE DEVELOPMENT OF A DRY SLOT MONDAY BETWEEN THE
REMNANTS OF NORBERT AND DEEPER MOISTURE TO THE EAST. BOTTOM LINE IS
THAT CONSIDERABLE UNCERTAINTY REMAINS...THOUGH IT APPEARS MORE
LIKELY THAT A WIDESPREAD 1 TO 2 INCHES OF RAIN CAN BE EXPECTED FROM
MARICOPA COUNTY EASTWARD THROUGH TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
ISOLATED SHOWERS/THUNDERSTORMS EXPECTED ACROSS SOUTH-CENTRAL ARIZONA
THIS MORNING...MAINLY ACROSS HIGHER TERRAIN AREAS TO THE NORTH AND
EAST OF PHOENIX...WITH SCT-BKN CLOUD DECKS AOA 10KFT. WINDS WILL
CONTINUE TO FAVOR EAST-SOUTHEAST GENERALLY 10KT OR LESS...AND MAY
SWITCH TO SOUTHWEST BRIEFLY FOR A COUPLE HOURS IF THERE IS
SUFFICIENT CLEARING OF MID-LEVEL CLOUD DECKS LATE THIS AFTERNOON.
ISOLATED SHOWER/THUNDERSTORMS ACTIVITY ENCROACHES ONCE AGAIN NEAR
TERMINALS THIS EVENING...BUT UNCERTAINTY IN TIMING/COVERAGE
WARRANTS LEAVING ANY MENTION OF WEATHER OUT OF THE TAFS AT THIS
TIME.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE TODAY...WITH MOSTLY
CLEAR SKIES AND JUST A FEW-SCT MID LEVEL CUMULUS. WINDS SHOULD
CONTINUE TO FAVOR SOUTH-SOUTHEAST GENERALLY 10KT OR LESS...EXCEPT
ALONG THE LOWER COLORADO RIVER VALLEY/NEAR KBLH WHERE GUSTS UP TO
25KT WILL ACCOMPANY ADDITIONAL MOISTURE SURGE AFTER 06Z FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
MONSOON MOISTURE WILL CONTINUE TO INCREASE AND SPREAD NORTH AND WEST
REACHING THE LOWER DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA BY SATURDAY. STORM CHANCES WILL CONTINUE THROUGH TUESDAY
BEFORE TRENDING DOWNWARD LATE IN THE PERIOD. HUMIDITIES WILL REMAIN
ELEVATED DURING THE PERIOD...WHILE TEMPERATURES TREND DOWNWARD.
WINDS WILL FOLLOW FAMILIAR SUMMERTIME SLOPE-VALLEY PATTERNS BUT WITH
SIGNIFICANT DISRUPTIONS DUE TO THUNDERSTORM ACTIVITY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...MEYERS
FIRE WEATHER...AJ/MEYERS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
512 AM MST THU SEP 4 2014
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL REMAIN MORE ISOLATED OVER THE HIGHER TERRAIN
THROUGH FRIDAY...BUT SHOULD BECOME MORE PERIODIC AND WIDESPREAD BY
THE END OF THE WEEKEND AND EARLY NEXT WEEK. HEAVY RAINFALL AND
LOCALIZED FLOODING WILL BE THE PRIMARY THREATS WITH THESE STORMS
LATE IN THE WEEKEND...WITH CLEARING ONLY SLOWLY OCCURRING NEXT WEEK.
&&
.DISCUSSION...
LATEST RAP STREAMLINE ANALYSIS SHOWS A WEAK TROUGH ACROSS SOUTHERN
CA WITH DEEPER MOISTURE LIFTING NORTHWARD ACROSS AZ IN A
SOUTHWESTERLY FLOW. ISOLATED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED EARLY THIS MORNING...MAINLY ACROSS NORTHWESTERN PORTIONS
OF MARICOPA COUNTY...PRODUCING BRIEF HEAVY RAIN. GIVEN THE LACK OF
ELEVATED CAPE...THE ACTIVITY IS PRESUMABLY BEING AIDED BY
VORTICITY-FORCED ASCENT AHEAD OF THE AFOREMENTIONED TROUGH AND A
GRAVITY WAVE PROPAGATING NORTHWESTWARD FROM EARLIER CONVECTION
ACROSS SOUTHERN AZ. LATEST HRRR HAS ASSIMILATED THIS ACTIVITY AND
SUGGESTS IT WILL TREK INTO CENTRAL AND NORTHERN AZ AS IT IS ABSORBED
INTO THE DEEPER SOUTHWESTERLY FLOW LATER THIS MORNING.
THEREAFTER...GLOBAL AND CONVECTIVE-ALLOWING MODELS INDICATE A WIDE
RANGE OF POSSIBILITIES. CONCEPTUALLY...STRONGEST ASCENT WILL SPREAD
NORTH AND EASTWARD INTO THE HIGHER ELEVATIONS OF EASTERN AZ.
HOWEVER...STEADILY INCREASING PWATS AS FAR WEST AS SOUTHWESTERN
MARICOPA COUNTY WARRANT A SLIGHT CHANCE OF PRECIPITATION THROUGHOUT
THE DAY. GIVEN THE INCREASING MOISTURE AND DECREASING
THICKNESSES...TEMPERATURES WILL BE A FEW DEGREES COOLER THAN THOSE
OBSERVED WEDNESDAY.
HIGH PRESSURE WILL BRIEFLY REBUILD ACROSS THE FORECAST AREA
FRIDAY...RESULTING IN A WEAKER WESTERLY FLOW.
CONSEQUENTLY...INCREASE IN PWATS WILL TAKE A BRIEF HIATUS ACROSS THE
LOWER DESERTS AND CONVECTION WILL BE MOST CONCENTRATED ACROSS
SOUTHERN AND EASTERN AZ.
MODELS REMAIN CONSISTENT THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK WITH THEIR DEPICTION OF DEEPER TROPICAL MOISTURE LIFTING
NORTHWARD OUT OF MEXICO AND INTO THE DESERT SOUTHWEST. ALTHOUGH
NEARBY HURRICANE NORBERT WILL LIKELY NOT HAVE A DIRECT IMPACT ON OUR
WEATHER...ITS INFLUENCE WILL BE FAVORABLE FOR PRECIPITATION WITHIN
THE REGION. OFFICIAL NHC FORECASTS INDICATE THAT THE WEAKENING TC
WILL MORE OR LESS TRACK PARALLEL TO THE BAJA PENINSULA...SUGGESTING
THAT MOISTURE TRANSPORT WILL BE MAXIMIZED ACROSS PORTIONS OF AZ.
MODELS SUGGEST THAT PWATS WILL APPROACH 2 INCHES
SUNDAY...INCREASING THE LIKELIHOOD OF HEAVY RAIN AND FLOODING.
RECENT TRENDS IN THE ECWMF ALSO SUGGEST A SOMEWHAT SLOWER ONSET OF
THE DEEPER MOISTURE...WITH THE BEST CHANCE FOR PRECIPITATION
OCCURRING SUNDAY AND MONDAY. HOWEVER...THE GFS PAINTS A DIFFERENT
PICTURE WITH THE DEVELOPMENT OF A DRY SLOT MONDAY BETWEEN THE
REMNANTS OF NORBERT AND DEEPER MOISTURE TO THE EAST. BOTTOM LINE IS
THAT CONSIDERABLE UNCERTAINTY REMAINS...THOUGH IT APPEARS MORE
LIKELY THAT A WIDESPREAD 1 TO 2 INCHES OF RAIN CAN BE EXPECTED FROM
MARICOPA COUNTY EASTWARD THROUGH TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
ISOLATED SHOWERS/THUNDERSTORMS EXPECTED ACROSS SOUTH-CENTRAL ARIZONA
THIS MORNING...MAINLY ACROSS HIGHER TERRAIN AREAS TO THE NORTH AND
EAST OF PHOENIX...WITH SCT-BKN CLOUD DECKS AOA 10KFT. WINDS WILL
CONTINUE TO FAVOR EAST-SOUTHEAST GENERALLY 10KT OR LESS...AND MAY
SWITCH TO SOUTHWEST BRIEFLY FOR A COUPLE HOURS IF THERE IS
SUFFICIENT CLEARING OF MID-LEVEL CLOUD DECKS LATE THIS AFTERNOON.
ISOLATED SHOWER/THUNDERSTORMS ACTIVITY ENCROACHES ONCE AGAIN NEAR
TERMINALS THIS EVENING...BUT UNCERTAINTY IN TIMING/COVERAGE
WARRANTS LEAVING ANY MENTION OF WEATHER OUT OF THE TAFS AT THIS
TIME.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE TODAY...WITH MOSTLY
CLEAR SKIES AND JUST A FEW-SCT MID LEVEL CUMULUS. WINDS SHOULD
CONTINUE TO FAVOR SOUTH-SOUTHEAST GENERALLY 10KT OR LESS...EXCEPT
ALONG THE LOWER COLORADO RIVER VALLEY/NEAR KBLH WHERE GUSTS UP TO
25KT WILL ACCOMPANY ADDITIONAL MOISTURE SURGE AFTER 06Z FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
MONSOON MOISTURE WILL CONTINUE TO INCREASE AND SPREAD NORTH AND WEST
REACHING THE LOWER DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA BY SATURDAY. STORM CHANCES WILL CONTINUE THROUGH TUESDAY
BEFORE TRENDING DOWNWARD LATE IN THE PERIOD. HUMIDITIES WILL REMAIN
ELEVATED DURING THE PERIOD...WHILE TEMPERATURES TREND DOWNWARD.
WINDS WILL FOLLOW FAMILIAR SUMMERTIME SLOPE-VALLEY PATTERNS BUT WITH
SIGNIFICANT DISRUPTIONS DUE TO THUNDERSTORM ACTIVITY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...KUHLMAN
FIRE WEATHER...AJ/MEYERS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
345 AM MST THU SEP 4 2014
.SYNOPSIS...
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL REMAIN MORE ISOLATED OVER THE HIGHER TERRAIN
THROUGH FRIDAY...BUT SHOULD BECOME MORE PERIODIC AND WIDESPREAD BY
THE END OF THE WEEKEND AND EARLY NEXT WEEK. HEAVY RAINFALL AND
LOCALIZED FLOODING WILL BE THE PRIMARY THREATS WITH THESE STORMS
LATE IN THE WEEKEND...WITH CLEARING ONLY SLOWLY OCCURRING NEXT WEEK.
&&
.DISCUSSION...
LATEST RAP STREAMLINE ANALYSIS SHOWS A WEAK TROUGH ACROSS SOUTHERN
CA WITH DEEPER MOISTURE LIFTING NORTHWARD ACROSS AZ IN A
SOUTHWESTERLY FLOW. ISOLATED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED EARLY THIS MORNING...MAINLY ACROSS NORTHWESTERN PORTIONS
OF MARICOPA COUNTY...PRODUCING BRIEF HEAVY RAIN. GIVEN THE LACK OF
ELEVATED CAPE...THE ACTIVITY IS PRESUMABLY BEING AIDED BY
VORTICITY-FORCED ASCENT AHEAD OF THE AFOREMENTIONED TROUGH AND A
GRAVITY WAVE PROPAGATING NORTHWESTWARD FROM EARLIER CONVECTION
ACROSS SOUTHERN AZ. LATEST HRRR HAS ASSIMILATED THIS ACTIVITY AND
SUGGESTS IT WILL TREK INTO CENTRAL AND NORTHERN AZ AS IT IS ABSORBED
INTO THE DEEPER SOUTHWESTERLY FLOW LATER THIS MORNING.
THEREAFTER...GLOBAL AND CONVECTIVE-ALLOWING MODELS INDICATE A WIDE
RANGE OF POSSIBILITIES. CONCEPTUALLY...STRONGEST ASCENT WILL SPREAD
NORTH AND EASTWARD INTO THE HIGHER ELEVATIONS OF EASTERN AZ.
HOWEVER...STEADILY INCREASING PWATS AS FAR WEST AS SOUTHWESTERN
MARICOPA COUNTY WARRANT A SLIGHT CHANCE OF PRECIPITATION THROUGHOUT
THE DAY. GIVEN THE INCREASING MOISTURE AND DECREASING
THICKNESSES...TEMPERATURES WILL BE A FEW DEGREES COOLER THAN THOSE
OBSERVED WEDNESDAY.
HIGH PRESSURE WILL BRIEFLY REBUILD ACROSS THE FORECAST AREA
FRIDAY...RESULTING IN A WEAKER WESTERLY FLOW.
CONSEQUENTLY...INCREASE IN PWATS WILL TAKE A BRIEF HIATUS ACROSS THE
LOWER DESERTS AND CONVECTION WILL BE MOST CONCENTRATED ACROSS
SOUTHERN AND EASTERN AZ.
MODELS REMAIN CONSISTENT THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK WITH THEIR DEPICTION OF DEEPER TROPICAL MOISTURE LIFTING
NORTHWARD OUT OF MEXICO AND INTO THE DESERT SOUTHWEST. ALTHOUGH
NEARBY HURRICANE NORBERT WILL LIKELY NOT HAVE A DIRECT IMPACT ON OUR
WEATHER...ITS INFLUENCE WILL BE FAVORABLE FOR PRECIPITATION WITHIN
THE REGION. OFFICIAL NHC FORECASTS INDICATE THAT THE WEAKENING TC
WILL MORE OR LESS TRACK PARALLEL TO THE BAJA PENINSULA...SUGGESTING
THAT MOISTURE TRANSPORT WILL BE MAXIMIZED ACROSS PORTIONS OF AZ.
MODELS SUGGEST THAT PWATS WILL APPROACH 2 INCHES
SUNDAY...INCREASING THE LIKELIHOOD OF HEAVY RAIN AND FLOODING.
RECENT TRENDS IN THE ECWMF ALSO SUGGEST A SOMEWHAT SLOWER ONSET OF
THE DEEPER MOISTURE...WITH THE BEST CHANCE FOR PRECIPITATION
OCCURRING SUNDAY AND MONDAY. HOWEVER...THE GFS PAINTS A DIFFERENT
PICTURE WITH THE DEVELOPMENT OF A DRY SLOT MONDAY BETWEEN THE
REMNANTS OF NORBERT AND DEEPER MOISTURE TO THE EAST. BOTTOM LINE IS
THAT CONSIDERABLE UNCERTAINTY REMAINS...THOUGH IT APPEARS MORE
LIKELY THAT A WIDESPREAD 1 TO 2 INCHES OF RAIN CAN BE EXPECTED FROM
MARICOPA COUNTY EASTWARD THROUGH TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
MID-LEVEL CLOUDINESS WITH DECKS DOWN TO AROUND 12K FEET WILL PERSIST
THROUGH AROUND 18Z THURSDAY. SCATTERED LIGHT SHOWERS WILL AFFECT
HIGHER TERRAIN AREAS TO THE NORTH AND EAST OF PHOENIX TONIGHT AND
THURSDAY MORNING...WHILE EXPECTING MAINLY VIRGA AND SPRINKLES ACROSS
THE LOWER DESERTS. WINDS HAVE ALREADY SWITCHED AROUND TO AN EASTERLY
DIRECTION AND ARE EXPECTED TO REMAIN OUT OF THE EAST THE REST OF THE
NIGHT. SHOULD SEE SOME ADDITIONAL ISOLATED SHOWER AND THUNDERSTORM
DEVELOPMENT ACROSS HIGHER TERRAIN AREAS THURSDAY AFTERNOON AND
EVENING...BUT NOT EXPECTING ANY IMPACTS TO THE PHOENIX TERMINALS.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES OVERNIGHT WITH SOME PERIODIC SCATTERED MID AND
HIGH CLOUDS COMING IN FROM ARIZONA. WINDS WILL REMAIN BELOW 12 KNOTS
THROUGH THE PERIOD AND GENERALLY OUT OF A SOUTHERLY DIRECTION.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
MONSOON MOISTURE WILL CONTINUE TO INCREASE AND SPREAD NORTH AND WEST
REACHING THE LOWER DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA BY SATURDAY. STORM CHANCES WILL CONTINUE THROUGH TUESDAY
BEFORE TRENDING DOWNWARD LATE IN THE PERIOD. HUMIDITIES WILL REMAIN
ELEVATED DURING THE PERIOD...WHILE TEMPERATURES TREND DOWNWARD.
WINDS WILL FOLLOW FAMILIAR SUMMERTIME SLOPE-VALLEY PATTERNS BUT WITH
SIGNIFICANT DISRUPTIONS DUE TO THUNDERSTORM ACTIVITY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...KUHLMAN
FIRE WEATHER...AJ/MEYERS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
920 AM CDT THU SEP 4 2014
.DISCUSSION...
327 AM CDT
MORNING THUNDERSTORM COVERAGE AND DURATION ALONG WITH IMPACT ON
DAYTIME TEMPERATURES ARE THE SHORT TERM CHALLENGES. THUNDER
CHANCES AND DEGREE OF COOL DOWN ARE THE MAIN LONG TERM POINTS OF
EMPHASIS TODAY.
SHORT TERM...TODAY AND TONIGHT...
AN ACTIVE ELEVATED WARM AND MOIST ADVECTION ZONE SUPPORTING AREAS
OF CONVECTION IS OVER THE REGION EARLY THIS MORNING. A SHORT WAVE
DISTURBANCE IN EASTERN IA AS OF 330 AM HAS BEEN AN INSTIGATOR FOR
MORE ORGANIZED CONVECTION OVER THE DVN CWA. A BROAD BUT STRONG
45KT LOW-LEVEL JET IS ADVECTING IN MOIST AIR AT THE BASE OF
STEEPENING MID-LEVEL LAPSE RATES OF 7-8 C/KM. THIS WILL REMAIN
SUPPORTIVE OF WIDESPREAD CONVECTIVE UPDRAFTS THROUGH 8-9 AM
BEFORE A PROBABLE DIMINISHING TREND AS STORMS APPROACH/MOVE OVER
CHICAGO AND THE I-55 CORRIDOR. A RAP ANALYSIS INDICATES FAIRLY
SHORT CORFIDI PROPAGATION VECTORS WITH NORTHWEST MID-LEVEL FLOW
PERPENDICULAR TO THE LLJ. SO ISOLATED HEAVY RAIN CONCERNS WILL BE
PRESENT AND HAVE BEEN SUPPORTED ON REGIONAL RADAR TRENDS. HAVE
INCREASED QPF IN TANDEM WITH HIGHER POPS THROUGH MID-MORNING.
A STRENGTHENING CAP ALONG WITH THE WEAKENING/EXIT OF THE
AFOREMENTIONED SHORT WAVE SHOULD LIMIT ANY CONVECTIVE CHANCES THIS
AFTERNOON. HOWEVER...SOME CLOUDS MAY LINGER INTO EARLY AFTERNOON.
WITH THAT AND SOME COMMUNITIES SEEING A SLOWER WARMING TREND
EARLY THIS MORNING WITH CLOUDS AND RAIN...HAVE LOWERED
TEMPERATURES IN THE NORTHEAST HALF OF THE FORECAST AREA BY A
COUPLE DEGREES. TEMPERATURES SHOULD STILL REALIZE 90 IN FAR
WESTERN/SOUTHWESTERN AREAS BASED ON 850/925MB TEMPERATURE
CLIMATOLOGY AND SUPPORT FROM PAST SIMILAR EVENTS PER THE CIPS
ANALOGS. HEAT INDEX READINGS IN THIS AREA...FROM BYRON TO GIBSON
CITY AND WESTWARD...WILL LIKELY APPROACH 100 DEGREES DUE TO
FORECAST LOWER 70 DEW POINTS.
A QUIET AND MILD EVENING IS EXPECTED. CONFIDENCE FOR PRECIP
REMAINING OUT OF THE AREA OVERNIGHT IS LOW. WHILE FRONTAL
CONVERGENCE REMAINS OFF TO THE NORTHWEST...QUITE A BIT OF
ELEVATED INSTABILITY WILL BE PRESENT AND OVERALL FORCING FOR
PRECIP IS LOW. BUT AS WE HAVE SEEN EARLY THIS MORNING...EVEN A
SUBTLE WAVE CAN CAUSE PROBLEMS. SO CONTINUE CHANCE POPS.
MTF
LONG TERM FRIDAY THROUGH WEDNESDAY...
THE MAIN FORECAST CONCERNS DURING THE LONG TERM PERIOD FOCUS ON THE
THREAT FOR SHOWERS AND THUNDERSTORMS...SOME POSSIBLY STRONG...AND
THE THREAT OF HEAVY RAINFALL FRIDAY AND FRIDAY NIGHT.
SURFACE LOW PRESSURE CURRENTLY ACROSS THE EASTERN DAKOTAS WILL
SHIFT NORTHEASTWARD TO NEAR JAMES BAY BY THE START OF THE PERIOD
(FRIDAY MORNING). THIS LOW WILL DRIVE A COLD FRONT SOUTHWARD OVER
NORTHERN ILLINOIS BY EARLY FRIDAY AFTERNOON. THE TIMING OF THIS
FRONTAL PASSAGE SHOULD ALLOW THE HEAT AND HUMIDITY TO LINGER...AT
LEAST FOR THE FIRST HALF OF THE DAY...ESPECIALLY ACROSS MY SOUTHERN
AREAS. THEREFORE...HIGHS ON FRIDAY LOOK TO ONCE AGAIN CREEP NEAR THE
90 DEGREE MARK...WITH HEAT INDICIES OF 95 TO 100 SOUTH OF INTERSTATE
80.
THUNDERSTORMS WILL LIKELY FIRE ACROSS FAR NORTHERN ILLINOIS EARLY ON
FRIDAY AS THE FRONT APPROACHES...AND LIKELY INCREASE IN AREAL
COVERAGE BY FRIDAY AFTERNOON. SURFACE BASED STORMS APPEAR
LIKELY...AHEAD OF THE FRONTAL BOUNDARY LATER FRIDAY MORNING AND INTO
THE AFTERNOON...WITH THE PREFRONTAL HIGH THETA-E LOWER LEVEL AIR MASS
EXPECTED TO INDUCE MLCAPES OF 2000-3000 J/KG. ALTHOUGH DEEP LAYER
SHEAR WILL BE SOMEWHAT LACKLUSTER...WITH ONLY AROUND 25 KT OF 0-6 KM
BULK SHEAR...THERE WILL BE A SMALL THREAT FOR MULTI-CELL CLUSTERS
CAPABLE OF PRODUCE STRONG WINDS. HOWEVER...IT APPEAR THE MAIN THREAT
FOR THIS MAY REMAIN SOUTH OF THE CHICAGO AND ROCKFORD AREAS.
THE OTHER THREAT WITH THESE STORMS...AS HAS BEEN THE CASE WITH
STORMS FOR THE LAST FEW WEEKS...IS VERY HEAVY RAINFALL. THE HIGH
THETA E AIR MASS FEATURING PWAT VALUES OF 1.8 TO 2 INCHES WILL LEAD
TO VERY EFFICIENT RAINFALL RATES...AND THIS COUPLED WITH THE FACT
THAT THE STEERING LAYER FLOW LOOKS TO RUN NEARLY PARALLEL TO THE
SURFACE FRONTAL ZONE...TRAINING CELLS ARE A GOOD POSSIBILITY. IT
ALSO APPEARS THAT SHOWERS...POSSIBLY WITH SOME EMBEDDED ELEVATED
THUNDERSTORMS...WILL LIKELY CONTINUE IN THE WAKE OF THE SURFACE
BOUNDARY INTO FRIDAY NIGHT AS AN ANA-LIKE FRONTAL PRECIP EVENT SETS
UP. MID LEVEL FGEN AND THE PROXIMATELY TO THE RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET ALL POINT TO CONTINUED FORCING TO SUPPORT
PRECIP INTO FRIDAY NIGHT.
GIVEN THE POSSIBILITIES OF A PERIOD OF VERY HEAVY RAINFALL...WITH
POSSIBLE TRAINING OF CELLS AHEAD OF THE FRONT...FOLLOWED BY A LONGER
PERIOD OF MODERATE PRECIP INTO FRIDAY NIGHT...HYDRO ISSUES COULD
BECOME A CONCERN.
THINGS QUIET DOWN AND BECOME MUCH COOLER FOR THE WEEKEND UNDER
NORTHERN FLOW. HIGH TEMPERATURES BY SATURDAY AND SUNDAY LOOK TO BE
IN THE LOW TO MID 70S. OVERNIGHT TEMPERATURES INTO SUNDAY MORNING
LOOKS TO BE QUITE CHILLY AS A SURFACE HIGH BUILDS OVERHEAD. THIS
LOOKS TO SET UP WIDESPREAD LOWER 50 DEGREE TEMPERATURES OUTSIDE OF
CHICAGO...WITH EVEN A FEW UPPER 40 DEGREE READINGS POSSIBLE IN THE
WESTERN SUBURBS.
TEMPERATURES LOOK TO MODERATE A BIT BACK INTO THE UPPER 70S INTO
NEXT WEEK. THE NEXT CHANCE FOR STORMS LOOKS TO ENTER THE PICTURE
AGAIN BY LATE MONDAY NIGHT AND TUESDAY AS ANOTHER DISTURBANCE TAKES
AIM ON THE AREA.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* TSRA THROUGH THE MORNING...LIKELY DECREASING EARLY AFTERNOON.
* VARIABLE WINDS NEAR THE TSRA...THEN POST CONVECTIVE WIND TRENDS.
LENNING
//DISCUSSION...UPDATED 14Z...
FAIRLY WIDESPREAD RAIN WITH AREAS OF EMBEDDED THUNDERSTORMS WILL
CONTINUE TO MOVE ACROSS THE AREA THIS MORNING. STILL BELIEVE THERE
WILL BE A GRADUAL FADE IN COVERAGE TOWARD LATE MORNING INTO EARLY
AFTERNOON...BUT IN THE NEAR TERM THINGS ARE HANGING TOGETHER
PRETTY WELL. AS PER EARLIER THINKING...THE PREVAILING WIND
DIRECTION WILL WANT TO BE SOUTH-SOUTHWEST OUTSIDE OF THE
STORMS...AND THE DIRECTION SHOULD FALL BACK INTO THAT DURING THE
AFTERNOON.
AFTER A QUIET AFTERNOON AND EVENING THERE WILL AGAIN BE A STRONG
LOW-LEVEL JET CAPABLE OF LOW-LEVEL WIND SHEAR LATE TONIGHT. THIS
ALSO WILL BRING THE POSSIBILITY OF SCATTERED SHRA/TSRA. THE
CHANCES WILL INCREASE THROUGH FRIDAY MORNING AS A COLD FRONT
APPROACHES FROM THE NORTH. THIS FRONT WILL EVENTUALLY SHIFT WINDS
TO THE NORTH TO NORTH-NORTHEAST DURING THE AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN JUST SHRA WITH VCTS IN THE
IMMEDIATE TERM...WITH INCREASING TSRA CHANCES TOWARD LATE
MORNING BEFORE ACTIVITY DISSIPATES.
* LOW CONFIDENCE IN WIND DIRECTIONS DURING TSRA...THUS THE VRB IN
THE TAF. BETTER CONFIDENCE OF BEING LIGHT ENOUGH TO MAINTAIN
WEST FLOW AT ORD...AND THEN TRENDING S OR SW THIS AFTERNOON.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHANCE OF SHRA AND SLIGHT CHANCE OF TSRA.
SATURDAY...VFR. NORTHEAST WINDS.
SUNDAY-MONDAY...VFR.
TUESDAY-WEDNESDAY...CHANCE OF TSRA.
MTF
&&
.MARINE...
155 AM CDT
THE WEATHER PATTERN ACROSS THE GREAT LAKES REGION WILL BE A BIT
ACTIVE OVER THE NEXT FEW DAYS...WITH SOME PERIODS OF STRONG WINDS IN
THE 25 TO 30 KT RANG...ALONG WITH A PERIOD OR TWO OF SHOWERS AND
STORMS.
A RATHER POTENT EARLY AUTUMN SEASON SURFACE LOW WILL MOVE FROM THE
EASTERN DAKOTAS EARLY THIS MORNING TO NEAR JAMES BAY BY EARLY FRIDAY
MORNING. THIS SYSTEM WILL CONTINUE TO INDUCE SOME STRONG SOUTHERN
WINDS OVER THE LAKE TODAY AND TONIGHT. IT APPEARS THE STRONGEST
WINDS UP TO AROUND 30 KT WILL OCCUR THIS EVENING ACROSS THE NORTHERN
HALF OF THE LAKE...WITH 20 TO 25 KT SOUTHERLY WINDS OVER THE
SOUTHERN HALF OF THE LAKE. THESE STRONG WINDS WILL RESULT IN SMALL
CRAFT ADVISORY CONDITIONS INTO THIS EVENING.
AS THE LOW SHIFTS OVER THE JAMES BAY FRIDAY MORNING...A TRAILING COLD
FRONT WILL SHIFT DOWN THE LAKE DURING THE DAY FRIDAY. WINDS WILL
SHIFT NORTHERLY INTO 15 TO 25 KT RANGE LATER FRIDAY AND INTO
SATURDAY...BEFORE ABATING LATER SATURDAY AS AN AREA OF SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN LAKES REGION. THESE NORTHERLY
WINDS DOWN THE FETCH OF LAKE MICHIGAN MAY AGAIN RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT AND SATURDAY...WITH WAVES
POSSIBLY IN THE 4 TO 7 FT RANGE.
THE WEATHER CONDITIONS LOOK TO QUIET DOWN FOR A COUPLE DAYS FOR
SUNDAY AND INTO EARLY NEXT WEEK AS SURFACE HIGH PRESSURE DOMINATES
ACROSS THE LAKES REGION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM THURSDAY.
&&
$$
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
630 AM CDT THU SEP 4 2014
.DISCUSSION...
327 AM CDT
MORNING THUNDERSTORM COVERAGE AND DURATION ALONG WITH IMPACT ON
DAYTIME TEMPERATURES ARE THE SHORT TERM CHALLENGES. THUNDER
CHANCES AND DEGREE OF COOL DOWN ARE THE MAIN LONG TERM POINTS OF
EMPHASIS TODAY.
SHORT TERM...TODAY AND TONIGHT...
AN ACTIVE ELEVATED WARM AND MOIST ADVECTION ZONE SUPPORTING AREAS
OF CONVECTION IS OVER THE REGION EARLY THIS MORNING. A SHORT WAVE
DISTURBANCE IN EASTERN IA AS OF 330 AM HAS BEEN AN INSTIGATOR FOR
MORE ORGANIZED CONVECTION OVER THE DVN CWA. A BROAD BUT STRONG
45KT LOW-LEVEL JET IS ADVECTING IN MOIST AIR AT THE BASE OF
STEEPENING MID-LEVEL LAPSE RATES OF 7-8 C/KM. THIS WILL REMAIN
SUPPORTIVE OF WIDESPREAD CONVECTIVE UPDRAFTS THROUGH 8-9 AM
BEFORE A PROBABLE DIMINISHING TREND AS STORMS APPROACH/MOVE OVER
CHICAGO AND THE I-55 CORRIDOR. A RAP ANALYSIS INDICATES FAIRLY
SHORT CORFIDI PROPAGATION VECTORS WITH NORTHWEST MID-LEVEL FLOW
PERPENDICULAR TO THE LLJ. SO ISOLATED HEAVY RAIN CONCERNS WILL BE
PRESENT AND HAVE BEEN SUPPORTED ON REGIONAL RADAR TRENDS. HAVE
INCREASED QPF IN TANDEM WITH HIGHER POPS THROUGH MID-MORNING.
A STRENGTHENING CAP ALONG WITH THE WEAKENING/EXIT OF THE
AFOREMENTIONED SHORT WAVE SHOULD LIMIT ANY CONVECTIVE CHANCES THIS
AFTERNOON. HOWEVER...SOME CLOUDS MAY LINGER INTO EARLY AFTERNOON.
WITH THAT AND SOME COMMUNITIES SEEING A SLOWER WARMING TREND
EARLY THIS MORNING WITH CLOUDS AND RAIN...HAVE LOWERED
TEMPERATURES IN THE NORTHEAST HALF OF THE FORECAST AREA BY A
COUPLE DEGREES. TEMPERATURES SHOULD STILL REALIZE 90 IN FAR
WESTERN/SOUTHWESTERN AREAS BASED ON 850/925MB TEMPERATURE
CLIMATOLOGY AND SUPPORT FROM PAST SIMILAR EVENTS PER THE CIPS
ANALOGS. HEAT INDEX READINGS IN THIS AREA...FROM BYRON TO GIBSON
CITY AND WESTWARD...WILL LIKELY APPROACH 100 DEGREES DUE TO
FORECAST LOWER 70 DEW POINTS.
A QUIET AND MILD EVENING IS EXPECTED. CONFIDENCE FOR PRECIP
REMAINING OUT OF THE AREA OVERNIGHT IS LOW. WHILE FRONTAL
CONVERGENCE REMAINS OFF TO THE NORTHWEST...QUITE A BIT OF
ELEVATED INSTABILITY WILL BE PRESENT AND OVERALL FORCING FOR
PRECIP IS LOW. BUT AS WE HAVE SEEN EARLY THIS MORNING...EVEN A
SUBTLE WAVE CAN CAUSE PROBLEMS. SO CONTINUE CHANCE POPS.
MTF
LONG TERM FRIDAY THROUGH WEDNESDAY...
THE MAIN FORECAST CONCERNS DURING THE LONG TERM PERIOD FOCUS ON THE
THREAT FOR SHOWERS AND THUNDERSTORMS...SOME POSSIBLY STRONG...AND
THE THREAT OF HEAVY RAINFALL FRIDAY AND FRIDAY NIGHT.
SURFACE LOW PRESSURE CURRENTLY ACROSS THE EASTERN DAKOTAS WILL
SHIFT NORTHEASTWARD TO NEAR JAMES BAY BY THE START OF THE PERIOD
(FRIDAY MORNING). THIS LOW WILL DRIVE A COLD FRONT SOUTHWARD OVER
NORTHERN ILLINOIS BY EARLY FRIDAY AFTERNOON. THE TIMING OF THIS
FRONTAL PASSAGE SHOULD ALLOW THE HEAT AND HUMIDITY TO LINGER...AT
LEAST FOR THE FIRST HALF OF THE DAY...ESPECIALLY ACROSS MY SOUTHERN
AREAS. THEREFORE...HIGHS ON FRIDAY LOOK TO ONCE AGAIN CREEP NEAR THE
90 DEGREE MARK...WITH HEAT INDICIES OF 95 TO 100 SOUTH OF INTERSTATE
80.
THUNDERSTORMS WILL LIKELY FIRE ACROSS FAR NORTHERN ILLINOIS EARLY ON
FRIDAY AS THE FRONT APPROACHES...AND LIKELY INCREASE IN AREAL
COVERAGE BY FRIDAY AFTERNOON. SURFACE BASED STORMS APPEAR
LIKELY...AHEAD OF THE FRONTAL BOUNDARY LATER FRIDAY MORNING AND INTO
THE AFTERNOON...WITH THE PREFRONTAL HIGH THETA-E LOWER LEVEL AIR MASS
EXPECTED TO INDUCE MLCAPES OF 2000-3000 J/KG. ALTHOUGH DEEP LAYER
SHEAR WILL BE SOMEWHAT LACKLUSTER...WITH ONLY AROUND 25 KT OF 0-6 KM
BULK SHEAR...THERE WILL BE A SMALL THREAT FOR MULTI-CELL CLUSTERS
CAPABLE OF PRODUCE STRONG WINDS. HOWEVER...IT APPEAR THE MAIN THREAT
FOR THIS MAY REMAIN SOUTH OF THE CHICAGO AND ROCKFORD AREAS.
THE OTHER THREAT WITH THESE STORMS...AS HAS BEEN THE CASE WITH
STORMS FOR THE LAST FEW WEEKS...IS VERY HEAVY RAINFALL. THE HIGH
THETA E AIR MASS FEATURING PWAT VALUES OF 1.8 TO 2 INCHES WILL LEAD
TO VERY EFFICIENT RAINFALL RATES...AND THIS COUPLED WITH THE FACT
THAT THE STEERING LAYER FLOW LOOKS TO RUN NEARLY PARALLEL TO THE
SURFACE FRONTAL ZONE...TRAINING CELLS ARE A GOOD POSSIBILITY. IT
ALSO APPEARS THAT SHOWERS...POSSIBLY WITH SOME EMBEDDED ELEVATED
THUNDERSTORMS...WILL LIKELY CONTINUE IN THE WAKE OF THE SURFACE
BOUNDARY INTO FRIDAY NIGHT AS AN ANA-LIKE FRONTAL PRECIP EVENT SETS
UP. MID LEVEL FGEN AND THE PROXIMATELY TO THE RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET ALL POINT TO CONTINUED FORCING TO SUPPORT
PRECIP INTO FRIDAY NIGHT.
GIVEN THE POSSIBILITIES OF A PERIOD OF VERY HEAVY RAINFALL...WITH
POSSIBLE TRAINING OF CELLS AHEAD OF THE FRONT...FOLLOWED BY A LONGER
PERIOD OF MODERATE PRECIP INTO FRIDAY NIGHT...HYDRO ISSUES COULD
BECOME A CONCERN.
THINGS QUIET DOWN AND BECOME MUCH COOLER FOR THE WEEKEND UNDER
NORTHERN FLOW. HIGH TEMPERATURES BY SATURDAY AND SUNDAY LOOK TO BE
IN THE LOW TO MID 70S. OVERNIGHT TEMPERATURES INTO SUNDAY MORNING
LOOKS TO BE QUITE CHILLY AS A SURFACE HIGH BUILDS OVERHEAD. THIS
LOOKS TO SET UP WIDESPREAD LOWER 50 DEGREE TEMPERATURES OUTSIDE OF
CHICAGO...WITH EVEN A FEW UPPER 40 DEGREE READINGS POSSIBLE IN THE
WESTERN SUBURBS.
TEMPERATURES LOOK TO MODERATE A BIT BACK INTO THE UPPER 70S INTO
NEXT WEEK. THE NEXT CHANCE FOR STORMS LOOKS TO ENTER THE PICTURE
AGAIN BY LATE MONDAY NIGHT AND TUESDAY AS ANOTHER DISTURBANCE TAKES
AIM ON THE AREA.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* A 2-3 HOUR PERIOD OF RAIN WITH OCCASIONAL EMBEDDED STORMS THIS
MORNING.
* TEMPORARY WIND SHIFT TO THE NORTHWEST AND THEN POSSIBLY
VARIABLE...BEFORE COMING BACK SOUTHERLY. OCCASIONAL GUSTS
THROUGHOUT.
* CHANCE FOR MORE SHRA/TSRA BEGINNING LATE TONIGHT AND INCREASING
THROUGH FRIDAY MORNING.
* CHANCE FOR LLWS AGAIN OVERNIGHT.
//DISCUSSION...UPDATED 12Z...
FAIRLY WIDESPREAD RAIN WITH AREAS OF EMBEDDED THUNDERSTORMS WILL
CONTINUE TO SHIFT EAST-SOUTHEAST ACROSS THE AREA THIS MORNING.
AFTER 13Z...THERE SHOULD BE A GRADUAL FADE IN COVERAGE OF RAIN AND
ESPECIALLY STORMS. STILL...THE STORMS SHOULD IMPACT ORD AND
MDW FOR 1.5 TO 3 HOURS. IN ADDITION...ORGANIZED STORMS THAT ARE
JUST NORTH OF ORD AT 1130Z DO HAVE AN OUTFLOW BOUNDARY THAT IS
PROGRESSING SOUTHWARD AND WILL TURN WINDS NORTHWESTERLY...AT LEAST
TEMPORARILY. THE WIND DIRECTION BEHIND THE STORMS MAY BRIEFLY TURN
SOUTHEAST AND GUSTY AS IS TYPICAL BEHIND ORGANIZED STORMS...THOUGH
THIS SHOULD BE BRIEF /LESS THAN 1-2 HRS/. THE PREVAILING WIND
DIRECTION WILL WANT TO BE SOUTH-SOUTHWEST OUTSIDE OF THE
STORMS...AND THE DIRECTION SHOULD FALL BACK INTO THAT DURING THE
AFTERNOON.
AFTER A QUIET AFTERNOON AND EVENING THERE WILL AGAIN BE A STRONG
LOW-LEVEL JET CAPABLE OF LOW-LEVEL WIND SHEAR LATE TONIGHT. THIS
ALSO WILL BRING THE POSSIBILITY OF SCATTERED SHRA/TSRA. THE
CHANCES WILL INCREASE THROUGH FRIDAY MORNING AS A COLD FRONT
APPROACHES FROM THE NORTH. THIS FRONT WILL EVENTUALLY SHIFT WINDS
TO THE NORTH TO NORTH-NORTHEAST DURING THE AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH IN TSRA OCCURRING. MEDIUM IN DURATION OF TSRA. THREE HOURS
IS LIKELY ON THE LONGER SIDE OF WHAT IS POSSIBLE...BUT FITS
RADAR AND SATELLITE TRENDS.
* MEDIUM IN WIND SPEEDS THIS MORNING AND REMAINING IN SOME FORM
WESTERLY. IF WINDS DO TURN SOUTHEAST AS THEY SOMETIMES DO AFTER
STORMS...IT IS LIKELY TO LAST LESS THAN TWO HOURS.
* LOW ON SHRA/TSRA OCCURRING LATE TONIGHT AND FRIDAY MORNING.
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHANCE OF SHRA AND SLIGHT CHANCE OF TSRA.
SATURDAY...VFR. NORTHEAST WINDS.
SUNDAY-MONDAY...VFR.
TUESDAY-WEDNESDAY...CHANCE OF TSRA.
MTF
&&
.MARINE...
155 AM CDT
THE WEATHER PATTERN ACROSS THE GREAT LAKES REGION WILL BE A BIT
ACTIVE OVER THE NEXT FEW DAYS...WITH SOME PERIODS OF STRONG WINDS IN
THE 25 TO 30 KT RANG...ALONG WITH A PERIOD OR TWO OF SHOWERS AND
STORMS.
A RATHER POTENT EARLY AUTUMN SEASON SURFACE LOW WILL MOVE FROM THE
EASTERN DAKOTAS EARLY THIS MORNING TO NEAR JAMES BAY BY EARLY FRIDAY
MORNING. THIS SYSTEM WILL CONTINUE TO INDUCE SOME STRONG SOUTHERN
WINDS OVER THE LAKE TODAY AND TONIGHT. IT APPEARS THE STRONGEST
WINDS UP TO AROUND 30 KT WILL OCCUR THIS EVENING ACROSS THE NORTHERN
HALF OF THE LAKE...WITH 20 TO 25 KT SOUTHERLY WINDS OVER THE
SOUTHERN HALF OF THE LAKE. THESE STRONG WINDS WILL RESULT IN SMALL
CRAFT ADVISORY CONDITIONS INTO THIS EVENING.
AS THE LOW SHIFTS OVER THE JAMES BAY FRIDAY MORNING...A TRAILING COLD
FRONT WILL SHIFT DOWN THE LAKE DURING THE DAY FRIDAY. WINDS WILL
SHIFT NORTHERLY INTO 15 TO 25 KT RANGE LATER FRIDAY AND INTO
SATURDAY...BEFORE ABATING LATER SATURDAY AS AN AREA OF SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN LAKES REGION. THESE NORTHERLY
WINDS DOWN THE FETCH OF LAKE MICHIGAN MAY AGAIN RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT AND SATURDAY...WITH WAVES
POSSIBLY IN THE 4 TO 7 FT RANGE.
THE WEATHER CONDITIONS LOOK TO QUIET DOWN FOR A COUPLE DAYS FOR
SUNDAY AND INTO EARLY NEXT WEEK AS SURFACE HIGH PRESSURE DOMINATES
ACROSS THE LAKES REGION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM THURSDAY TO 10 PM THURSDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
741 AM EDT THU SEP 4 2014
.SYNOPSIS...
ISSUED AT 403 AM EDT THU SEP 4 2014
A WARM FRONT WILL MOVE NORTH TODAY AND BRING A SMALL CHANCE FOR
SHOWERS AND THUNDERSTORMS TO NORTHERN INDIANA AND SOUTHWEST LOWER
MICHIGAN THROUGH EARLY AFTERNOON. SKIES WILL BE PARTLY TO MOSTLY
CLOUDY THIS MORNING FOLLOWED BY CLEARING THIS AFTERNOON. IT WILL
BECOME MORE HUMID AND WARMER BY THIS AFTERNOON WITH HIGHS
REACHING THE MIDDLE TO UPPER 80S. THERE WILL BE A SLIGHT CHANCE
FOR A THUNDERSTORM TONIGHT...MAINLY AFTER MIDNIGHT AND NORTH OF
HIGHWAY 30. IT WILL REMAIN VERY MUGGY AND WARM OVERNIGHT WITH LOWS
IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EDT THU SEP 4 2014
IMMEDIATE CONCERN IN THE SHORT TERM PERIOD IS HANDLING OF UPSTREAM
CONVECTION THAT HAS FIRED OVERNIGHT. LOW LEVEL JET NOSING INTO
THETA E GRADIENT HAS ALLOWED CONVECTION TO DEVELOP OVER IA AND IT
CONTINUES TO RIDE NOSE OF THIS LLJ AND TRACK EAST. WEAK CONVECTION
HAS TRIED TO FIRE AHEAD OF THIS AREA OVER EASTERN IL AND SOUTHERN
LAKE MICHIGAN BUT IT HAS STRUGGLED SO FAR WITH DRIER AIR STILL IN
PLACE. AS THETA E RIDGE SHIFTS EAST EARLY THIS MORNING EXPECT
CONVECTIVE COMPLEX TO CONTINUE ITS TREK EAST AS WELL. AS DAYTIME
HEATING COMMENCES AND LLJ RELAXES EXPECT THIS CONVECTION TO
DISSIPATE THROUGH THE MORNING HOURS. HIRES MODELS HAVE BEEN TRYING
TO HANDLE THIS ALONG WITH LARGER COMPLEX FURTHER NORTH BUT HAVE
BEEN STRUGGLING WITH EVOLUTION DETAILS. LATEST RUC AND HRRR HAVE
PICKED UP ON IA COMPLEX BUT SEEM UNDERDONE AND HAVE THIS
DISSIPATING BEFORE REACHING THE AREA. EXPECT NEXT FEW RUNS TO BE
MORE AGGRESSIVE BASED ON LATEST RADAR/SATELLITE/LIGHTNING TRENDS.
30 TO 40 KNOT LLJ FEEDING THIS SEEMS TO BE KEEPING IT ON AN
EASTWARD TRACK DESPITE 850-300MB THICKNESS LINES SHOWING A
POSSIBLE MOVEMENT TO THE SOUTHEAST. WILL HAVE TO MONITOR TRENDS
NEXT FEW HOURS CLOSELY BUT FOR NOW HAVE EXPANDED POPS AND
INCREASED SKY COVER THIS MORNING TO COVER MOST OF WESTERN AND
NORTHERN THIRD OF CWA. WILL TAPER POPS OFF BY AFTERNOON WITH SKIES
BECOMING PARTLY CLOUDY TO MOSTLY SUNNY. THIS POSES THE NEXT
PROBLEM WITH HIGH TEMPS FOR TODAY. SOUNDINGS SUGGEST MIXING TO
AROUND 900MB WHICH WILL YIELD HIGHS IN THE MID TO UPPER 80S.
OBVIOUSLY NOW LOOKING AT SLOWER WARMING TRENDS THIS MORNING WITH
SATELLITE SHOWING INCREASED CLOUD DEVELOPMENT. STILL EXPECT A
RAPID WARMUP LATER IN THE DAY ONCE CLOUDS ERODE SO STAYED WITH MID
80S EXCEPT IN FAR SOUTHWEST WHERE UPPER 80S STILL LIKELY.
MODEL SOUNDINGS SHOW DECENT CAPPING INVERSION THIS AFTERNOON DESPITE
MUCAPES CLIMBING TO BETWEEN 1K AND 2K J/KG. DEWPOINTS WILL CREEP
INTO THE UPPER 60S MAKING IT FEEL QUITE HUMID. NOT MUCH FOCUS FOR
CONVECTION TONIGHT BUT MOISTURE RICH AIR WILL BE IN PLACE WITH
ELEVATED INSTABILITY SO IT WILL NOT TAKE MUCH TO SPARK AN ISOLATED
TSRA. WILL KEEP SLIGHT CHANCE POPS ACROSS NORTHERN TWO THIRDS OF
AREA WELL AHEAD OF MAIN COLD FRONT.
&&
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 403 AM EDT THU SEP 4 2014
MAIN FOCUS FRIDAY-FRIDAY NIGHT REMAINS CONVECTIVE CHANCES/COVERAGE
AS TRAILING COLD FRONT FROM POTENT SHORTWAVE TRACKING NE TO JAMES
BAY SAGS SOUTHEAST INTO A MOIST/UNSTABLE AIRMASS. MUCH OF FRIDAY
MORNING-EARLY AFTERNOON SHOULD REMAIN MAINLY DRY IN CAPPED WARM
SECTOR (850 MB TEMPS 21C)...ALTHOUGH CANNOT COMPLETELY RULE OUT
CONVECTIVE REMNANTS/OUTFLOW SURVIVING INTO NORTHERN/WESTERN ZONES IN
LOW LEVEL THETA-E ADVECTION REGIME. EXPECTED STRONG DIURNAL HEATING
AND POOLED 70F DEWPOINTS NEAR FRONT...CONCURRENT WITH OVERSPREAD OF
WEAK 20-30M 5H HEIGHT FALLS...SHOULD BE SUFFICIENT TO BREAK CAP/FIRE
CONVECTION ALONG THE SAGGING FRONTAL ZONE BY MID-LATE AFTERNOON.
COVERAGE REMAINS QUESTIONABLE HOWEVER WITH BETTER MID LEVEL HEIGHT
FALLS/FORCING INITIALLY CONFINED NORTH. THIS REMAINS THE PRIMARY
REASON FOR HOLDING SHY OF LIKELY POPS AT THIS FCST RANGE. POST
FRONTAL LAG OF STRONGER MID LEVEL FLOW/DEEP SHEAR AND WHAT SHOULD BE
A VERY UNSTABLE ENVIRONMENT (MLCAPE 2500 J/KG PLUS) HINTS AT A LOW
END SEVERE THREAT (ISOLATED) WITH SHORT-LIVED UPDRAFTS CAPABLE OF
PRODUCING STRONG OUTFLOWS/DOWNBURSTS. FAIR AMOUNT OF CAPE IN THE
M10-M30 LAYER ALSO SUGGESTIVE OF A LOW END HAIL THREAT AS WELL.
OVERSPREAD OF BETTER HEIGHT FALLS/RIGHT ENTRANCE UPPER JET SUPPORT
WILL TIGHTEN/DEEPEN THE FRONTAL ZONE AS IT DROPS THROUGH
SOUTHERN/EASTERN ZONES FRIDAY NIGHT...WITH AMPLE MOISTURE AND
POTENTIAL FOR LOWER AMPLITUDE SHORTWAVE ENERGY TO PROPAGATE THROUGH
IN SW FLOW PROBABLY ENOUGH TO HELP GENERATE ADDITIONAL RAIN/THUNDER
ALONG FRONTAL SLOPE. WITH THAT SAID...ONCE AGAIN HELD SHY OF LIKELY
POPS GIVEN NORMAL UNCERTAINTIES WITH CONVECTION AND RECENT MAINLY
DRY FRONTAL PASSAGES IN SIMILAR SETUPS.
A FEW SHOWERS/LOW CLOUDS MAY LINGER INTO SATURDAY MORNING ACROSS
SOUTHERN/EASTERN ZONES...WITH THE REST OF THE WEEKEND INTO EARLY
NEXT WEEK MUCH COOLER/DRIER AS BROAD HIGH PRESSURE BUILDS IN WAKE OF
FRONT/SHORTWAVE TROUGH. RETURN FLOW TIMED WITH THE NEXT ROUND OF
HEIGHT FALLS ON THE BACKSIDE OF THIS AREA OF HIGH PRESSURE BRINGS
SHOWER/STORM CHANCES BACK INTO THE FORECAST BY THE MIDDLE OF NEXT
WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 740 AM EDT THU SEP 4 2014
TSRA COMPLEX EXTENDING FROM WRN LWR MI SWWD INTO WEST CENTRAL IL
MAKING SLOW EASTWARD PROGRESS EARLY THIS MORNING. EXPECT
BACKING/WKNG LLJ THIS MORNING WILL RESULT IN A MORE NEWD TREND
WITH MOVEMENT OF MCS AS WELL AS A DIMINISHING TREND. WOULDN`T
TOTALLY RULE OUT A SHRA/TSRA REACHING KSBN THROUGH 14-15Z BUT
THREAT REMAINS LOW ENOUGH NOT TO INCLUDE TEMPO GROUP. OTRWS VFR
CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD AT BOTH TERMINALS.
AGAIN TONIGHT THERE IS SOME POTENTIAL FOR TSRA AS LOW LEVEL
THETA-E ADVECTION/CONVERGENCE OVERSPREAD THE AREA BUT ATTM
CONFIDENCE TOO LOW TO INCLUDE IN TAFS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...STEINWEDEL
AVIATION...JT
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
638 AM CDT THU SEP 4 2014
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 304 AM CDT THU SEP 4 2014
COLD FRONT FROM EASTERN SD INTO CO WILL MOVE SOUTHEAST ACROSS THE
STATE BY FRIDAY MORNING. A WAVE WILL MOVE NORTHEAST ALONG THE
FRONT ON FRIDAY...PASSING SOUTH OF IA DURING THE DAY. HIGH
PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND. NEXT FRONTAL
SYSTEM SLATED TO MOVE THROUGH THE AREA ABOUT TUESDAY.
&&
.SHORT TERM /TODAY/...
ISSUED AT 304 AM CDT THU SEP 4 2014
MAIN FORECAST CONCERN WAS ANOTHER HOT AND HUMID DAY AND
WITH POTENTIAL FOR CONVECTION LATE THIS AFTERNOON. LEANED TOWARD THE
SLIGHTLY WARMER ECMWF/GFS FOR HIGHS TODAY AS THERE SHOULD BE SOME
DECENT MIXING TO AROUND 900MB AND WAA THROUGHOUT THE DAY. THE WAA
HAS KEPT TEMPS UP OVERNIGHT IN THE MID TO UPPER 70S. A SHARP COLD
FRONT IS SLATED TO PUSH INTO NORTHWEST LATE THIS AFTERNOON INTO THE
EVENING AND CAP LOOKS TO HOLD THROUGH MUCH OF THE DAY. THE HIRES
MODELS (NMM/ARW) BREAK OUT SOME ISOLATED STORMS BY 19-20Z TODAY.
HOWEVER...THE 04.00Z HOPWRF/04.05Z HRRR KEYING IN ON A VERY WEAK
SHORTWAVE OVER SOUTHERN NEBRASKA AND HAS STORMS DEVELOPING BY AROUND
16-17Z. HOWEVER...BELIEVE THE STRONG CAP IN PLACE WILL HOLD UNTIL
THE COLD FRONT LATER THIS AFTERNOON ENTERS THE STATE. ONE THING TO
NOTE...IF WEAK ISOLATED CONVECTION THAT THE HOPWRF/HRRR DOES
DEVELOP...WILL HINDER MAX TEMPS A LITTLE TODAY OVER THE SOUTH. AT
ANY RATE...HAVE POPS INCREASING PAST 20Z OVER THE WEST TO NORTHWEST
AS THE COLD FRONT BEGINS TO SAG SOUTHEAST INTO THE STATE.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 304 AM CDT THU SEP 4 2014
THUNDERSTORMS ARE LIKELY TO DEVELOP ALONG AND JUST BEHIND THE COLD
FRONT DAY AS IT SLIDES SOUTHEAST AIRMASS IS QUITE CAPPED
INITIALLY...BUT COLD AIR ALOFT WILL ALLOW THE CAP TO BREAK AND
EXPECT A LINE OF THUNDERSTORMS TO DEVELOP AND MOVE TROUGH THE
STATE. RAIN WILL CONTINUE OVER THE SOUTH AND EAST ON FRIDAY AS A
S/WV RESULTS IN A WAVE LIFTING NORTHEAST ALONG THE FRONT FRIDAY.
HIGH PRESSURE WILL PUSH IN AND DOMINATE THE WEATHER OVER THE
WEEKEND WITH COOLER AND DRIER AIR IN PLACE. THE NEXT FRONTAL
SYSTEM WILL BE WEAKER...BUT WILL BRING A CHANCE FOR RAIN IN THE
MONDAY TUESDAY TIMEFRAME. DO NOT EXPECT TO SEE THE WARMING WITH
THE NEXT SYSTEM THAT IS OCCURRING BEFORE THE CURRENT COLD FRONT.
FURTHER AHEAD...A STRONGER FRONT WILL BRING A CHANCE FOR RAIN
ABOUT THURSDAY. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
LATER NEXT WEEK WITH THE A COOL PUSH OF FALL AIR OVER THE UPPER
MIDWEST. THE MODELS HAVE BECOME MORE CONSISTENT WITH THIS BOTH IN
MODEL TO MODEL AND RUN TO RUN CONTINUITY.
&&
.AVIATION...04/12Z
ISSUED AT 638 AM CDT THU SEP 4 2014
WINDS WILL CONTINUE TO INCREASE THIS MORNING AS MIXING TO AROUND
2000-2500 FEET BY 21Z THIS AFTERNOON AND WITH THE PRESSURE
GRADIENT STRENGTHENING...INCREASED WIND GUSTS FOR ALL TAF SITES.
KEPT MENTION OF VCTS AS LOW CONFIDENCE WITH LOCATION OF CONVECTION
LATE THIS AFTERNOON INTO THE EVENING. POTENTIAL FOR MVFR VIS/CIGS
TONIGHT AND WILL HAVE TO BE REEVALUATED AT THE 18Z TAFS.
OTHERWISE...COLD FRONT THROUGH THIS EVENING WILL SHIFT WINDS TO
THE WEST THEN NORTHWEST TOWARD FRIDAY MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS SEP 14
SHORT TERM...PODRAZIK
LONG TERM...MS SEP 14
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1154 AM EDT THU SEP 4 2014
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 330 AM EDT THU SEP 4 2014
AN ACTIVE WEATHER PATTERN IS TAKING SHAPE FROM TODAY THROUGH FRIDAY
EVENING. A WARM FRONT WILL BRING CHANCES FOR SHOWERS AND STORMS
ESPECIALLY THIS MORNING. ADDITIONAL SHOWERS AND STORMS ARE EXPECTED
TONIGHT THROUGH FRIDAY. THE RAIN SHOULD END FROM NORTH TO SOUTH
ACROSS SOUTHWEST LOWER MICHIGAN FRIDAY NIGHT AS A COLD FRONT DROPS
SOUTH THROUGH THE REGION. LOCALLY HEAVY RAIN IS A DISTINCT
POSSIBILITY. IT SHOULD BECOME QUITE WARM THIS AFTERNOON WITH
READINGS RISING INTO THE MIDDLE TO UPPER 80S IN MANY LOCATIONS. A
COOLER WEEKEND IS ANTICIPATED BEHIND THE COLD FRONT WITH HIGHS IN
THE LOWER 70S.
&&
.UPDATE...
ISSUED AT 1152 AM EDT THU SEP 4 2014
I LOWERED THE FORECAST HIGH TEMPERATURES TO THE 80 TO 85 DEGREE
RANGE AND RAISED THE POP TO NEAR CONDITIONAL INTO LATE MORNING. I
THEN ALLOWED THE POP TO TAIL OFF TO BELOW 15 PCT BY MID AFTERNOON
AS MORE STABLE AIR MOVES INTO THE AREA.
OUR MCV THAT ROLLED THROUGH OUR CWA HAS CREATED A WAKE LOW FEATURE
AND THE ENTIRE COMPLEX IS SINKING SOUTHEAST WITH TIME. THIS
RESULTED IN SOME LOCALLY HIGH WINDS. MEANWHILE THE RAP MODEL
SHOWS THE MCV TRACKING ESE INTO SE LOWER MICHIGAN/NORTHWEST OHIO
BY MID AFTERNOON. MEANWHILE THERE IS STRONG PUSH OF HOT AIR AT MID
LEVEL BEING ADVECTED IN BEHIND THE WARM FRONT. RAP MODEL SOUNDING
SHOW THE AIR OVER SOUTHWEST LOWER MICHIGAN BECOMING VERY STABLE
WITH CIN VALUES OVER 250 J/KG BY 00Z AS A RESULT OF THAT DEEP PUSH
OF HOT AIR. THIS WILL END ALL PRECIPITATION BY EARLY AFTERNOON AND
ALLOW THE SUN TO FINALLY COME OUT AND HEAT THE AIR. EVEN
SO...GIVEN HOW CLOUDY IS IS NOW...HARD TO IMAGINE IT WILL GET MUCH
WARMER THAN THE MID 80S... SO I LOWERED THE FORECAST HIGH FROM THE
UPPER 80S TO THE MID 80S.
THE LOW LEVEL JET SETS UP AGAIN TONIGHT BUT THE AXIS OF IT IS
NORTH OF HTL. THE MOISTURE TRANSPORT VECTORS IN THE 1000/850 LAYER
ARE MORE IMPRESSIVE TONIGHT THAN LAST NIGHT BUT THEY ARE FOCUSED
NEAR TVC. GIVEN THE CAPE DUE TO THE WARM AIR ALOFT I HAVE TO
WONDER HOW MUCH OF THE CONVECTION FROM WI/UPPER MICHIGAN WILL MAKE
IT SOUTH INTO THE GRR CWA. WE WILL HAVE TO LOOK MORE CLOSELY AT
THAT LATER.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 330 AM EDT THU SEP 4 2014
AREAL EXTENT AND TIMING OF THUNDERSTORMS IS THE BIGGEST CHALLENGE
WITH THE FORECAST THIS MORNING. SHOWERS AND STORMS ARE CURRENTLY
DEVELOPING TO OUR WEST IN A ZONE OF SOLID MOISTURE ADVECTION AT
850MB/S. THIS PUSH OF MOISTURE SURGES INTO THE AREA THIS MORNING AND
WILL BRING THE CHANCE OF SHOWERS AND STORMS TO ALL AREAS. A BIT OF A
LULL IS EXPECTED THIS AFTERNOON AS WE BREAK INTO THE WARM SECTOR OF
THE SYSTEM. AT LEAST PARTIAL CLEARING SHOULD ALLOW TEMPERATURES TO
PUSH WELL INTO THE 80S. GIVEN THE TIMING OF THE STORMS NOT EXPECTING
SEVERE WEATHER THIS MORNING.
THUNDERSTORMS SHOULD BECOME FAIRLY NUMEROUS AGAIN TONIGHT AS ANOTHER
SURGE OF MOISTURE ADVECTS INTO SOUTHWEST LOWER MICHIGAN. GIVEN
OVERNIGHT TIMING AGAIN...WE ARE NOT EXPECTING SEVERE WEATHER BUT IT
IS NOT OUT OF THE REALM OF POSSIBILITIES. IN FACT WE ARE ON THE
EASTERN EDGE OF A SLIGHT RISK AREA THAT CROSSES MASON INTO OCEANA
COUNTY. WIND AND HAIL WOULD BE THE MAIN THREATS.
FRIDAY INTO FRIDAY NIGHT...THE COLD FRONT PROGRESSES SOUTH THROUGH
THE AREA. THE LLJ PEELS AWAY TO THE EAST FRIDAY...BUT WE COULD BE
LOOKING AT STRONG DESTABILIZATION IN THE SOUTHERN HALF OF THE
FORECAST AREA. THE INSTABILITY ALONE MAY BE ENOUGH TO GENERATE SOME
SCATTERED SEVERE WEATHER. FEEL THE FRONT WILL AID IN FOCUSING STORMS
AND LOCALLY HEAVY RAINFALL AS WELL. THE RAIN SHOULD GRADUALLY TAPER
OFF FRIDAY EVENING FROM NORTH TO SOUTH.
SATURDAY WILL BE A MAINLY SUNNY AND DRY DAY WITH HIGHS IN THE LOWER
70S.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT THU SEP 4 2014
HIGH PRESSURE WILL BUILD IN TO BRING FAIR WEATHER WITH SEASONABLE
TEMPERATURES THIS WEEKEND WITH MAX TEMPS RANGING FROM THE UPPER 60S
TO MIDDLE 70S AND MIN TEMPS IN THE 40S TO LOWER 50S.
SOME CLOUDS WILL BEGIN TO MOVE IN MONDAY AS SOUTHERLY FLOW DEVELOPS
AND RESULTS IN GRADUALLY INCREASING MOISTURE ON THE BACK SIDE OF THE
DEPARTING HIGH PRESSURE RIDGE. DRY WEATHER WILL CONTINUE MONDAY
THROUGH MONDAY NIGHT.
DEVELOPING LOW PRESSURE AND A WARM FRONT WILL BRING POTENTIAL FOR
RAIN AND THUNDERSTORMS AS EARLY AS TUESDAY WITH A LITTLE BETTER
CHANCE FOR PRECIPITATION TUESDAY NIGHT THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 754 AM EDT THU SEP 4 2014
AREA OF SHOWERS AND THUNDERSTORMS WILL WORK THROUGH THE TAF SITES
THROUGH MIDDAY...ENDING FROM NORTHWEST (KMKG) TO SOUTHEAST (KJXN)
BETWEEN 13Z AND 16Z OR SO. THE EXPECTATION IS THAT THE SHOWERS AND
STORMS WILL TAPER OFF THIS MORNING WITH SKIES CLEARING OUT THIS
AFTERNOON. MAINLY VFR CONDITIONS ARE IN PLACE WITH HIGH BASED
STORMS OCCURRING. SOME BRIEF PERIODS OF MVFR CAN BE EXPECTED IN
THE HEAVIER STORMS. VFR SHOULD PREVAIL THIS AFTERNOON AS WE TRY TO
SCATTER OUT.
WINDS WILL PICK UP THIS MORNING FROM THE SOUTH-SOUTHWEST AT 10-25
KNOTS. THE HIGHEST WINDS WILL BE SEEN AT KMKG.
OVERNIGHT ANOTHER ROUND OF SHOWERS AND STORMS ARE EXPECTED TO WORK
THROUGH THE TAF SITES...AFTER 04Z TO 06Z. CEILINGS AND
VISIBILITIES MAY DIP INTO THE MVFR CATEGORY AGAIN...BUT AT THIS
POINT JUST MENTIONED VCTS WORDING.
&&
.MARINE...
ISSUED AT 1152 AM EDT THU SEP 4 2014
BASED ON EARLIER MARINE OBSERVATIONS AS THE STORMS WERE MOVING
THROUGH I EXPANDED THE SMALL CRAFT ADVISORY FARTHER SOUTH. THE
PORT SHELDON BUOY AT 1120 AM STILL HAD GUSTS TO 29 KNOTS WITH 6
FOOT WAVES. SOUTH HAVEN AT GUSTS AS HIGH AS 33 KNOTS BUT THAT HAS
SINCE DIMINISHED TO 15 TO 20 KNOTS. WEB CAMS FROM PORT
SHELDON...GRAND HAVEN...AND MUSKEGON SHOW WHITE CAPS ON THE WATER
WITH 4 TO 6 FOOT WAVES (BUOY DATA). SO BOTTOM LINE IT MAKES SENSE
TO KEEP THE KEEP THE ADVISORY AND BEACH HAZARD STATEMENT GOING.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT THU SEP 4 2014
PERIODS OF THUNDERSTORMS ARE EXPECTED FROM THIS MORNING THROUGH
FRIDAY EVENING. PWAT VALUES RISE INTO THE 1.50 TO 2.00 INCH RANGE AS
SOUTHERLY FLOW STREAMS IN DEEP MOISTURE. THE DEEPEST MOISTURE LOOKS
TO BE IN PLACE THURSDAY NIGHT THROUGH FRIDAY WHICH IS WHEN THE
HEAVIEST RAINS WILL LIKELY FALL. RIVER LEVELS REMAIN WELL WITHIN
BANK THOUGH...SO RIVER FLOODING IS NOT REALLY ANTICIPATED. SWATHS OF
1 TO 2 INCH RAINFALLS REMAIN A POSSIBILITY...ESPECIALLY ACROSS
CENTRAL LOWER MICHIGAN AND POTENTIALLY ALONG I94. EVEN WITH THESE
TOTALS WE ARE PROBABLY NOT LOOKING AT MUCH MORE THAN SOLID WITHIN
BANK RISES. REGARDING LOCALIZED AREAL FLOODING FROM THE STORMS
THEMSELVES...THIS REMAINS A POSSIBILITY AS WELL GIVEN THE DEEP
MOISTURE IN PLACE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY MORNING FOR MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT FRIDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...LAURENS
AVIATION...DUKE
HYDROLOGY...DUKE
MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 AM EDT THU SEP 4 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU SEP 4 2014
AS FIGURED IT HAS BEEN A FAIRLY ACTIVE NIGHT AT LEAST IN TERMS OF
SHRA/TSRA. NO SEVERE WEATHER IN OUR CWA...WITH BULK OF TSRA STAYING
MAINLY OVER SOUTHERN CWA EARLIER TONIGHT. VERY HEAVY RAIN DID OCCUR
EARLIER AS KIMT AND KMNM BOTH ENDED UP WITH AROUND AN INCH OF RAIN
IN 45-60 MIN. STRONGEST STORMS IN THE AREA NOW ARE CROSSING CNTRL LK
MICHIGAN. A LULL HAS DEVELOPED OVER UPR MICHIGAN...EXCEPT VERY FAR
EAST WHERE RAIN AND EMBEDDED TSRA WILL RUN ITS COURSE OVER NEXT
COUPLE HOURS.
WESTERLY FLOW ALOFT AND THE MAIN SHORTWAVE IS DRIVING ACROSS
SOUTHERN SASKATCHEWAN AND INTO WESTERN NORTH DAKOTA. SPC
MESOANALYSIS PAGE SHOWS ISOLD-SCT STRONG-SEVERE STORMS OVER NORTH
DAKOTA ARE FORMING IN WARM AIR ADVECTION REGION ALONG AND NORTH OF
GRADIENT OF 1-6KM MUCAPE OF 2000-3000 J/KG MAXIMIZED FM SOUTHERN TO
CENTRAL PLAINS. ACTIVITY IS ALSO JUST NORTH OF THE +12C ISOTHERM AT
H7. CONVECTIVELY INDUCED WAVE IS ALSO FORMING OVR NORTH DAKOTA PER
WV LOOP AND REGIONAL RADAR LOOPS. HIGH RES MODELS...SUCH AS THE HRRR
AND NSSL WRF AND WRF-ARW/NMM BEGAN TO PICK UP ON THIS LATE WED
EVENING AND CONTINUE TO INDICATE THIS MCV WITH ASSOCIATED MCS WILL
CONTINUE TRACKING EAST ALONG MUCAPE/H85 DWPNT GRADIENT AND WITH THE
H85-H3 WEST TO EAST ORIENTED THICKNESS LINES AND FOLLOWING THE
FORWARD PROPAGATING CORFIDI VECTORS. CERTAINLY POSSIBLE THIS COMPLEX
MAY GROW UPSCALE/PRODUCE WIDESPREAD SEVERE WX GIVEN THE SUFFICIENT
EFFECTIVE SHEAR OVER 40 KTS PRESENT FM DAKOTAS ACROSS MINNESOTA AND
ALSO DUE TO THE FAVORABLE 0-3KM SHEAR OVER 30 KTS THAT WOULD HELP
THE SHEAR/COLD POOL BALANCE NEEDED TO SUSTAIN SUCH A COMPLEX. SFC
WARM FRONT STILL WELL TO THE SOUTHWEST OF HERE THIS MORNING...MOST
LIKELY OVER SOUTHERN MINNESOTA TO SOUTHWEST WISCONSIN. SEEMS THAT
THIS COMPLEX WOULD HAVE TO TAKE A VERY HARD TURN RIGHT...AND QUICKLY
FOR IT TO NOT IMPACT UPR GREAT LAKES LATER THIS MORNING OR MAYBE NOW
AS LATEST HRRR SHOWS...EARLY AFTN. THE LATER ARRIVAL OF A COMPLEX...
ALSO A GREATER SEVERE THREAT FOR WIND/HAIL OVER OUR CWA. CONFIDENCE
IS NOT HIGH ENOUGH TO PUT SEVERE MENTION IN GRIDS...BUT WILL CONTINUE
TO MENTION IN HWO AND VARIOUS SOCIAL MEDIA.
UNFORTUNATELY...SINCE THIS AREA OF TSRA IS A NEW DEVELOPMENT
COMPARED TO EXPECTED SHRA/TSRA EVOLUTION FOR TODAY LOOKED LIKE
12-24 HR AGO HAD TO REWORK POPS/WX CONSIDERABLY THROUGH MID AFTN
TODAY. WHATEVER COMPLEX WORKS ACROSS UPR MICHIGAN SHOULD BE ON THE
WANE AFT 18Z-21Z. WARM FRONT PROBABLY WILL HAVE TOUGH TIME MAKING IT
TO THE CWA TODAY GIVEN THE SHRA/TSRA THAT WENT THROUGH OVERNIGHT AND
THIS ADDITIONAL AREA OF TSRA POSSIBLE LATER TODAY. CAPPING THAT
LOOKED SO FIERCE FOR THIS AFTN 24 HR AGO...NOW NOT AS MUCH...
POSSIBLY BECAUSE THE ATMOSPHERE WILL BE WORKED OVER FROM SHRA/TSRA
MOVING IN FM NORTH DAKOTA LATER TODAY. THUS...THINK THAT THE H85
MOISTURE TRANSPORT INTO AN AREA OF MID-LEVEL FGEN WILL BE ENOUGH TO
REDEVELOP SHRA/TSRA OVER WESTERN CWA BY LATE THIS AFTN. ADDITIONAL
POTENTIAL FOR SEVERE WITH THIS ACTIVITY AS WELL GIVEN MLCAPES AROUND
1500 J/KG AND EFFECTIVE SHEAR 40-55 KTS. SUPERCELL STRUCTURES WOULD
STILL BE POSSIBLE WITH RIGHT MOVING SUPERCELLS SHOWING A WEST-EAST
MOTION WHILE LEFT MOVERS WOULD MOVE MORE SOUTHWEST TO NORTHEAST.
MEAN STORM MOTION WOULD BE WEST SOUTHWEST TO EAST NORTHEAST. ALL
MOTIONS ARE SWIFT...PROBABLY IN THE 30-40 MPH RANGE.
IN REGARDS TO SPECIFIC SEVERE POTENTIAL...SPC HAS OUR AREA FIRMLY IN
THE 15 PCT RISK FOR SEVERE HAIL AND DAMAGING WINDS. THIS COULD OCCUR
WITH THIS INITIAL COMPLEX IF IT MAKES INTO THE AREA. LIKELY DAMAGING
WINDS WOULD BE THE MAIN THREAT IF THAT OCCURS. IF ADDITIONAL STORMS
CAN REDEVELOP IN WAKE OF THIS ACTIVITY LATE THIS AFTN/EARLY THIS
EVENING AHEAD OF STRONG COLD FRONT...THE DEGREE OF SHEAR INDICATES
SUPERCELLS WOULD BE POSSIBLE ESPECIALLY IF MLCAPES RECOVER TOWARD
1500-2000 J/KG. ALL SEVERE MODES COULD OCCUR LATE THIS AFTN IF THAT
OCCURS...EVEN POTENTIAL FOR TORNADOES AS 0-1KM SHEAR IS OVER 30 KTS
AND ML LCL/S HEIGHTS WOULD BE VERY FAVORABLE AT LESS THAN 1000M.
FREEZING LEVELS MAINLY BLO 13KFT AND MODELS INDICATE WOULD HAVE TO
SEE CORES GET TO 30-35KFT FOR QUARTER SIZED HAIL. THIS SEEMS VERY
ACHIEVABLE GIVEN THE SHEAR AND INSTABILITY FORECAST. THE WILD CARD IS
EXTENT OF INSTABILITY THAT WILL BE LEFT IN WAKE OF THE INITIAL
COMPLEX. MODELS COULD BE OVERPLAYING THAT...AND THUS THE ADDITIONAL
SEVERE THREAT. TIME WILL TELL.
LARGER SCALE FORCING IN TERMS OF SHORTWAVE AND DEEP LAYER LIFT
SWINGS ACROSS THE CWA FM WEST TO EAST AND EXPECT SCT-NMRS SHOWERS
AND TSRA IN THE EVENING. MAY BE AT LEAST SOME LINGERING RISK OF
STRONGER STORMS DURING THIS TIME. DRYING PUNCHES IN IN MID-LEVELS
OVERNIGHT AND COLD FRONT ARRIVES. EXPECT SHRA/TSRA CHANCES TO BE
WANING OVER THE EAST CWA AFTER 08Z.
FINALLY...GRADIENT WINDS WILL BE VERY GUSTY...FIRST OVER NORTHERN LK
MICHIGAN TODAY IN THE SOUTH-SOUTHWEST FLOW...THEN LATE TONIGHT OVER
LK SUPERIOR IN WAKE OF THE FRONT WHEN WINDS SHIFT TO THE WEST
NORTHWEST. ISALLOBARIC ADDITION TO THE WIND COULD LEAD TO MARGINAL
GALES IN BOTH OF THESE AREAS...AT LEAST FOR A FEW HOURS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 451 AM EDT THU SEP 4 2014
FRI...EXPECT ANY LINGERING SHRA/TSRA OVER THE FAR ERN CWA TO DEPART
BY MID MORNING. OTHERWISE...CAA DROPPING 850 MB TEMPS INTO THE 6C-8C
RANGE WILL KEEP MAX READINGS IN THE LOWER 60S WEST TO AROUND 70 NEAR
LAKE MICHIGAN. AS THE STRONG LOW OVER NRN ONTARIO LIFTS NE INTO NRN
QUEBEC AND HIGH PRESSURE OVER THE PLAINS BUILDS INTO THE WRN GREAT
LAKES...GUSTY WNW WINDS WILL GRADUALLY DIMINISH. HOWEVER...WINDS
GUSTING TO AROUND 30 KNOTS MAY BE POSSIBLE EARLY OVER THE
KEWEENAW...ESPECIALLY FOR THE WEST FACING HIGHER TERRAIN.
FRI NIGHT INTO SUNDAY...DRY WEATHER IS EXPECTED TO PREVAIL AS THE
REGION REMAINS UNDER THE INFLUENCE OF HIGH PRESSURE THAT GRADUALLY
BUILDS INTO THE SRN GREAT LAKE. PCPN ASSOCIATED WITH SHRTWVS MOVING
THROUGH NRN ONTARIO BOTH FRI NIGHT AND SAT NIGHT SHOULD REMAIN NORTH
OF LAKE SUPERIOR GIVEN THE DRY AIRMASS OVER THE REGION. THE MAIN
IMPACT ON UPPER MI WILL BE TO REINFORCE THE SEASONABLY COOL AIR.
MON-WED...THE GFS/GEFS AND ECWMF WERE IN GENERAL AGREEMENT THAT THE
ZONAL PATTERN MONDAY WILL GIVE WAY TO TROUGHING INTO THE NRN PLAINS
SHIFTING TOWARD THE UPPER MS VALLEY. THERE ARE DIFFERENCES IN
HANDLING THE DETAILS OF THE TIMING/STRENGTH OF THE PLAINS TROUGH AND
A MORE DOMINANT LOW NEAR HUDSON BAY. WITH BOTH THE MID LEVEL AND SFC
TROUGH APPROACHING THE AREA...PCPN CHANCES WILL INCREASE FROM TUE
INTO WED. HOWEVER...PCPN AMOUNTS WILL GENERALLY BE LIGHT WITH ONLY A
SLIGHT CHANCE FOR TSRA...MAINLY ON TUE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 741 AM EDT THU SEP 4 2014
LOW CLOUDS HAVE EXPANDED BEHIND THE DEPARTING AREA OF SHRA/TSRA
OVER THE UPPER LAKES THIS MORNING. LIFR CONDITIONS AT KIWD/KSAW
WILL GRADUALLY BECOME MVFR BUT THIS MAY TAKE UNTIL LATE MORNING.
BIGGER CONCERN...AT LEAST FOR KIWD IS COMPLEX OF STRONG TO SEVERE
STORMS ROLLING EAST ACROSS MINNESOTA. CHANCES ARE INCREASING THAT AT
LEAST REMNANT OF TSRA WILL SURVIVE TO KIWD. ADDED TSRA IN THE TAFS
AND WENT WITH MVFR VSBY FOR NOW. RAIN COULD FALL HEAVY WHEN TSRA
MOVE THROUGH. SOME CHANCE OF WIND GUSTS OVER 40 KTS AS WELL...THOUGH
NOT ENOUGH CONFIDENCE TO INCLUDE IN TAF. AT KCMX MAY SEE SHRA WITH
EMBEDDED TSRA LATE MORNING INTO EARLY AFTN...AND IF THIS WHOLE
COMPLEX HOLDS TOGETHER IT WOULD REACH KSAW EARLY AFTN AS WELL.
ONCE THIS LEADING COMPLEX OF TSRA IS THROUGH...ATTN TURNS TO
APPROACHING COLD FRONT AS THIS MAY TRIGGER ISOLD/SCT STRONG TO SVR
TSTMS LATER THIS AFTN/EVENING. CONFIDENCE IN DEVELOPMENT IS STILL
VERY LOW AT THIS POINT. INCLUDED VCSH MENTION WITH THE FROPA...BUT
ONLY OPTED FOR TSRA MENTION AT KSAW AS THAT IS WHERE MODEL FCST
GUIDANCE SUGGESTS A BETTER POTENTIAL FOR TSRA. WINDS BECOME GUSTY
LATE TONIGHT AT KCMX IN WAKE OF THE FRONT WITH GUSTS OVER 30 KTS
POSSIBLE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 AM EDT THU SEP 4 2014
A LOW PRESSURE SYSTEM OVER THE EASTERN DAKOTAS WILL LIFT TO THE
NORTHEAST THROUGH NRN MN TODAY AND TO JAMES BAY BY FRIDAY MORNING.
MOIST AIR MOVING OVER THE LAKE UNDER SOUTHEASTERLY WINDS WILL LEAD
TO PATCHY/AREAS OF FOG OVER PORTIONS OF THE LAKE TONIGHT THROUGH
FRIDAY MORNING. A COLD FRONT MOVING EAST ACROSS LAKE SUPERIOR
TONIGHT WILL BRING GUSTY WESTERLY WINDS TO 30KTS THROUGH FRIDAY
MORNING. WINDS WILL DIMINISH FRIDAY AFTERNOON/NIGHT AS A HIGH
PRESSURE RIDGE BUILDS OVER THE UPPER GREAT LAKES REGION. THIS WILL
LEAD TO LIGHT WINDS THROUGH THE WEEKEND AND THE FIRST PART OF NEXT
WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...JLA
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
609 AM CDT THU SEP 4 2014
.UPDATED FOR 12Z AVIATION DISCUSSION...
ISSUED AT 552 AM CDT THU SEP 4 2014
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM CDT THU SEP 4 2014
MAIN CONCERNS WITH THIS PERIOD ARE THE FORWARD PROPAGATING MCS THAT
IS EXPECTED TO DEVELOP AND RACE ACROSS CENTRAL MN EARLY THIS
MORNING. THIS WILL BE FOLLOWED BY HOT AND HUMID TEMPERATURES ACROSS
EASTERN MN AND WESTERN WI...WITH A FEW SHOWERS AND THUNDERSTORMS
POSSIBLE BY LATE AFTERNOON. MEANWHILE A SEASONABLY STRONG COLD FRONT
WILL PUSH THROUGH THE REGION AND BRING BREEZY NORTHWESTERLY WINDS
OVERNIGHT ALONG WITH COOL/DRY AIR.
THE FIRST ORDER OF DISCUSSION IS THE SEVERE WEATHER THREAT THIS
MORNING RELATED TO THE CONVECTION ACROSS NORTH DAKOTA. HIRES MODELS
SUCH AS THE HRRR AND 00/03Z RUNS OF THE HOPWRF ARE IN REMARKABLE
AGREEMENT THAT THIS CONVECTION WILL INTENSIFY AS IT MOVES INTO
WESTERN MINNESOTA AND DEVELOP INTO A BOW ECHO. THIS STORM MODE SEEM
VERY PLAUSIBLE CONSIDERING THE ORIENTATION OF THE DEEP LAYER SHEAR
VECTORS IN RELATION TO THE WARM FRONT AND MUCAPE GRADIENT...SO
INCLUDED DAMAGING WINDS IN THE FORECAST ACROSS THE FAR NORTHERN TIER
OF COUNTIES. THE HRRR SEEMS TO HAVE A BETTER HANDLE ON THE ONGOING
CONVECTION...AND IT KEEPS THE MAJORITY OF THE FORECAST PRECIP NORTH
OF THE CWA. HOWEVER BASED ON THE ACTUAL LOCATION OF THE WARM FRONT
STILL THINK THERE IS LEGITIMATE RISK ALONG AND NORTH OF A LINE FROM
ALEXANDRIA MN TO RICE LAKE WI.
AS THE COLD POOL BECOMES WELL ESTABLISHED THIS CONVECTION WILL RACE
EASTWARD. MEANWHILE THE UPPER LEVEL WAVE AND SURFACE LOW WILL SLOWLY
MAKE THEIR WAY INTO NORTHERN MN ALLOWING THE WARM SECTOR TO
DESTABILIZE THROUGHOUT THE DAY ON THURSDAY. DEPENDING ON THE
RESIDUAL CLOUD COVER...AFTERNOON HIGH TEMPS COULD EASILY CLIMB INTO
THE 90S ACROSS SOUTHEASTERN MN AND WESTERN WI. FOR NOW DID NOT GO
MUCH ABOVE GUIDANCE SINCE SHOWERS AND THUNDERSTORMS COULD DEVELOP
ALONG THE TRAILING COLD FRONT LIMITING THE DIABATIC HEATING. A FEW
OF THESE STORMS ARE LIKELY TO BE SEVERE AS FORECAST SOUNDINGS
SHOW NEARLY 4000J/KG OF CAPE BY LATE AFTERNOON AND AROUND 30KTS OF
DEEP LAYER SHEAR ALONG AND EAST OF THE MN/WI BORDER.
THIS AFOREMENTIONED COLD FRONT IS THE LAST REAL AREA OF INTEREST.
AGAIN FORECAST SOUNDINGS SHOW STRONG COLD AIR ADVECTION IN THE WAKE
OF THE FRONT. THIS WILL KEEP THE BOUNDARY LAYER WELL MIXED WITH
NORTHWESTERLY WIND GUSTS OF 20 TO 30MPH EXPECTED TO PREVAIL AFTER
DARK. THEREFORE INCREASED THE WINDS THURSDAY NIGHT...AND USED LESS
BIAS-CORRECTED GRIDS FOR OVERNIGHT LOWS SINCE THE TEMPERATURES
SHOULD BE RATHER UNIFORM. ALSO RAISED CLOUD COVER SINCE SOUNDINGS
SHOW SATURATION ABOVE THE BOUNDARY LAYER.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 AM CDT THU SEP 4 2014
THE FIRST HALF OF THE LONG TERM LOOKS RATHER QUIET. THERE WILL BE
A SPLIT FLOW PATTERN DEVELOPING WITH THE SUBTROPICAL JET TO THE
SOUTH KEEPING THE HEAT CONFINED TO THE SOUTHERN STATES...AND THE
POLAR JET ACROSS CENTRAL CANADA KEEPING THE UNSEASONABLY COOL AIR
TO THE NORTH - AT LEAST FOR THE TIME BEING. SURFACE HIGH PRESSURE
WILL GUARANTEE MOSTLY CLEAR SKIES THROUGH SUNDAY NIGHT.
THINGS BECOME A BIT MORE COMPLEX NEXT WEEK AS THE POLAR JET
BEGINS TO SINK SOUTH. A MORE ACTIVE PATTERN IS IN THE OFFING WITH
SEVERAL DISTURBANCES SKIRTING ALONG THE NORTHERN TIER OF THE U.S.
HOWEVER...WITH THE SUBTROPICAL JET REMAINING SOUTH IT DOES NOT
APPEAR ANY OF THESE DISTURBANCES WILL HAVE A WHOLE LOT OF MOISTURE
TO WORK WITH. THEREFORE KEPT POPS IN THE CHC RANGE.
EVENTUALLY THE JETS WILL PHASE AND CARVE OUT A DEEP TROUGH OVER
CANADA AND THE NORTHERN U.S. SOME TIME DURING THE MIDDLE OF NEXT
WEEK. THE MUCH COOLER TEMPS ACCOMPANYING THIS TROUGH SHOULD MARK
THE FIRST CRACK AT AUTUMN WEATHER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 552 AM CDT THU SEP 4 2014
VERY CHALLENING FORECAST WITH CIGS TODAY...FOLLOWED BY PRECIP
CHANCES THIS AFTERNOON...AND THE WINDS BEHIND THE FRONTAL PASSAGE
TONIGHT. LONG STORY SHORT...THE STRONGEST STORMS WILL STAY NORTH
OF THE TAF SITES THIS MORNING. MVFR/IFR CLOUDS COULD DEVELOP SOUTH
OF THIS COMPLEX...AND AFFECT ALL SITED EXCEPT KRWF. A FEW
SCATTERED SHWOERS AND THUNDERSTORMS ARE EXPECTED LATE THIS
AFTERNOON ALONG THE MN/WI BORDER AND POINTS EAST. TONIGHT FORECAST
SOUDNINGS SHOW A SECOND SURGE OF COLD AIR BEHIND THE FRONT SO
EXPECT WIND GUSTS TO PICK UP FROM THE NORTHWEST AFTER 06Z.
KMSP...
MVFR CIGS THIS MORNING SHOULD GIVE WAY TO VFR CONDITIONS. A FEW
SHOWERS AND THUNDERSTORMS ARE POSSIBLE LATER THIS AFTERNOON...BUT
COVERAGE WILL BE LIGHT SO NOT INCLUDING ANYTHING BEYOND VCSH.
WINDS WILL GRADUALLY BECOME SW TO NW TODAY...WITH STORNGER GUSTS
PICKING UP LATE TONIGHT THROUGH EARLY FRIDAY MORNING.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS NW 10G20 KTS.
SAT...VFR. WINDS W 5-10 KTS.
SUN...VFR. WINDS SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
835 AM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE OFF THE EAST COAST WILL CAUSE TO WARM AND HUMID AIR
MOVING UP FROM THE SOUTH. THE MUGGY AIR WILL LAST INTO THE
WEEKEND. A COLD FRONT WILL LIKELY PUSH SOUTH ACROSS THE REGION
SATURDAY...FOLLOWED BY COOLER AIR DUE TO A CANADIAN HIGH PRESSURE
AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE AND LARGE SCALE SUBSIDENCE OVER THE REGION WAS
LEADING TO GENERALLY CLEAR TO PTLY CLOUDY SKIES. THERE WERE A FEW
SMALL AREAS OF BKN-OVC STRATO CU AND ALTO CU ACROSS THE FAR
SE...AND FAR NW PARTS OF THE CWA. THE DEEPER VALLEYS CONTAINING
LARGE STREAMS AND RIVERS ARE FOGGY...WITH LOCALIZED VSBYS UNDER
1/4SM.
THE BULK OF THE CLOUDS WILL PROBABLY DRIFT NE ACROSS SCENT AND
SERN SECTIONS OF THE CWA THROUGH THE MORNING HOURS...AND
SPREAD INTO THE MID SUSQ REGION DURING THE MIDDAY AND AFTERNOON
HOURS /WITHIN AN AREA OF 1-1.5 INCH PWAT AIR/.
THE BROKEN CLOUDS WILL HAMPER HEATING A BIT...BUT THE 8H TEMPS IN
THE MID TEENS WILL MAKE FOR A WARM DAY. TEMPS WILL MAX OUT ABOUT
5F ABOVE NORMAL. THE HEATING AND MOISTURE IN THE SOUTHERN AND
CENTRAL MTS WILL POP ISOLD SHRA OFF THE HIGH HILLS. COVERAGE COULD
BE ENOUGH FOR A 30 POP IN THE LAURELS/SC MTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE LIGHT S/SE WIND WILL TRY TO POOL MOISTURE UP IN THE CENTRAL
MTS TONIGHT. NOCTURNAL COOLING WILL AGAIN LEAD TO SOME FOG IN THE
VALLEYS...BUT THE EXTENT OF THE CLOUD COVER WILL LIMIT IT TO
MAINLY THE NWRN MTS. THE MUGGY AIR WILL KEEP TEMPS FROM FALLING
OUT OF THE MID 60S IN MANY PLACES BUT U50S STILL POSSIBLE IN THE
NWRN MTS WHERE IT MAY BE MOST-CLEAR.
FRIDAY SEEMS LIKE A MORE-LIKELY DAY FOR SOME CONVECTION AS THE
CAPES COULD REACH 1500-2000 JOULES IF WE GET RID OF THE LID/CAP.
BUT THE HIGH HEIGHTS AND WARM MID LEVELS WILL LIKELY LIMIT
CONVECTION TO MAINLY THE S/E WHERE THE TEMPS COULD GET INTO THE
U80S. LACK OF WIND IN THE PROFILE WILL KEEP THE WORRY OF SEVERE
VERY LOW.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU ON SAT. THE POPS WILL STAY RATHER LOW OVER
MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT. BUT THE NWRN
COUNTIES WILL LIKELY SEE STROMS MOVE DOWN FROM THE NW AFTER
MIDNIGHT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SUBTROPICAL RIDGE CENTERED OVER THE CAROLINAS WILL BE SUPPRESSED
BY SHORTWAVE ENERGY AND MODERATE-INTENSITY SFC CYCLONE TRACKING
NEWD FROM THE NRN HIGH PLAINS ACROSS WRN ONTARIO INTO NRN QUEBEC
BY SAT. ITS TRAILING COLD FRONT REMAINS THE FOCUS FOR PCPN
HEADING INTO THE WEEKEND WITH CONTINUED UNCERTAINTY IN THE SEWD
FRONTAL PROGRESSION. A SLOWER TREND MAY BE EMERGING IN THE 12Z
GFS/GEFS WITH ITS FRONTAL ZONE ALIGNING CLOSER WITH THE ECMWF/GEM
BY 00Z SUN. MAX POPS SHIFT FROM NW TO SE OVER THE CWA FROM 06Z SAT
TO 00Z SUN. HAVE RAISED POPS INTO THE LIKELY CATEGORY SAT BASED ON
DIMINISHING SPREAD AMONGST MDL DATA...NEARLY ALL OF WHICH TRACK
COLD FRONT THRU CENTRAL PA DURING THE DAYLIGHT HRS OF SATURDAY.
AHEAD OF CDFRONT...TEMPS ARE LIKELY TO PEAK ON FRIDAY WITH MEAN
H85 TEMPS +18-20C SUPPORTING WIDESPREAD HIGHS 85-90F.
THE NEXT QUESTION CONCERNS HOW QUICKLY THE FRONT CLEARS SRN PA ON
SUNDAY WITH MODEL DATA SUGGESTING THE UPPER LEVEL FRONT HANGS
BACK ALONG THE APPLCHNS/MID-ATLC PIEDMONT...AS ENERGY IS SHEARED
NEWD THRU THE NRN NEW ENGLAND AND CANADIAN MARITIMES AND FLOW
ALOFT BECOMES ORIENTED MORE WESTERLY. MEAN PW FIELDS SHOW DRIER
AIR SPREADING INTO THE REGION FROM THE NW BEHIND THE FRONT AS
HIGH PRES BECOMES ESTABLISHED IN THE NORTHEAST BY EARLY NEXT
WEEK. THEREFORE EXPECT TEMPS AND POPS TO TREND LOWER DURING THE
LATER PERIODS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
PATCHY DENSE FOG OBSERVED IN THE VALLEYS OF CENTRAL PA AT
DAWN...WITH KAOO...KUNV AND KIPT ALL EXPERIENCING IFR OR LIFR
CONDS AS OF 11Z. CLIMATOLOGY AND LATEST HRRR INDICATE FOG WILL
BURN OFF BY 13Z-14Z AND MDL SOUNDINGS INDICATE A NEAR CERTAINTY
OF WIDESPREAD VFR CONDS FOR THE REST OF TODAY...AS HIGH PRES
PASSES EAST OF THE REGION.
CLEAR SKIES AND A LIGHT WIND WILL PROMOTE AREAS OF FOG LATE
TONIGHT WITH MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF IFR
CONDS NEAR DAWN FRIDAY.
OUTLOOK...
FRI...PATCHY AM FOG. ISOLD PM TSRA IMPACTS POSS SOUTHERN PA.
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...DANGELO/LAMBERT
SHORT TERM...DANGELO
LONG TERM...LA CORTE
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
601 AM MDT THU SEP 4 2014
.UPDATE...
ISSUED AT 600 AM MDT THU SEP 4 2014
LOOKING AT LATEST RAP GUIDANCE AS WELL AS 12Z KUNR SOUNDING...WILL
ALLOW FOOTHILLS WIND ADVISORY TO EXPIRE ON SCHEDULE.
&&
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 215 AM MDT THU SEP 4 2014
08Z SURFACE ANALYSIS HAD LOW NEAR KPIR WITH COLD FRONT DRIVING
THROUGH CENTRAL NE INTO EASTERN CO. 3-6MB/3HR PRESSURE RISES
BEHIND FRONT SUPPORTING GUSTY WINDS ON THE SD PLAINS EARLY THIS
MORNING. AS BOUNDARY LAYER DECOUPLES AND PRESSURE RISES DECREASE
EARLY THIS MORNING...THERE WILL BE A SMALL DECREASE IN WIND SPEEDS
UNTIL A COUPLE OF HOURS AFTER SUNRISE WHEN MIXING WILL COMMENCE
AGAIN AND GUSTY NORTHWEST WINDS WILL PICK BACK UP OVER THE
NORTHWEST SD PLAINS. RAP/NAM/GFS SUGGEST 25-30KT BOUNDARY LAYER
WINDS THROUGH EARLY AFTERNOON. WILL EXPAND ADVISORY FOR THESE
AREAS. HAVE THE FOOTHILLS GOING UNTIL 600 AM...AND WILL DECIDE
WHETHER TO EXTEND TO EXPIRE PRODUCT BASED ON 12Z OBSERVATIONS.
TEMPERATURES WILL BE DRASTICALLY COOLER THAN YESTERDAY.
TONIGHT...HIGH PRESSURE BUILDS INTO THE CWA. GOOD RADIATIONAL
COOLING EXPECTED WITH PATCHY FROST OVER THE HIGHER BLACK HILLS
POSSIBLE.
FRIDAY...HIGH PRESSURE SHIFTS SOUTHEAST INTO THE LOWER MO RIVER
VALLEY. WEAK RETURN FLOW SETS UP OVER THE CWA. LOW LEVEL THETA-E
RIDGE OVER WY MAY SUPPORT AFTERNOON/EVENING -TSRA NEAR SOUTHWEST
PORTIONS OF CWA...BUT POPS LOW ENOUGH TO LEAVE OUT SENSIBLE WEATHER
AT THIS TIME. TEMPERATURES WILL REMAIN COOLISH.
&&
.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 215 AM MDT THU SEP 4 2014
STRONG UPPER RIDGING WILL DEVELOP ACROSS THE WRN HALF OF THE
CONUS FOR THE WEEKEND. THIS WILL BRING MOSTLY SUNNY SKIES AND
WARMING TEMPS THROUGH SUNDAY. DID ADD SL CHC POPS TO THE BLKHLS
SUNDAY.
A BROAD UPPER TROF MOVES INTO THE WESTERN STATES EARLY NEXT WEEK
WITH SOUTHWESTERLY FLOW DEVELOPING OVER THE HIGH PLAINS. COULD SEE
SOME VERY ISOLATED THUNDERSTORM ACTIVITY SOMETIME EARLY NEXT
WEEK...BUT TIMING AND PLACEMENT OF ACTIVITY IS PROBLEMATIC. MODELS
HAVE BEEN SHOWING BETTER CHANCES FOR PRECIP TOWARD MIDWEEK WITH THE
ECMWF BEING THE MUCH WETTER SOLUTION. HAVE ADJUSTED POPS BASED ON BEST
GUESS...BUT WOULD STILL LIKE TO SEE BETTER MODEL CONSISTENCY. WITH
BROAD TROF MOVING IN...TEMPERATURES WILL GRADUALLY DECREASE FROM
MONDAY INTO THE MIDDLE OF NEXT WEEK. THE ECMWF IS BRINGING IN MUCH
COLDER AIR INTO THE REGION WHILE THE GFS KEEPS THE COLD AIR WELL
NORTH OF THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 600 AM MDT THU SEP 4 2014
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. GUSTY NW
WINDS WILL CONTINUE TODAY OVER MUCH OF THE WRN SD PLAINS. WINDS
WILL THEN DECREASE LATE THIS AFTN INTO THE EVNG.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 3 PM MDT THIS AFTERNOON FOR SDZ001-002-
012>014-031-032-073.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...HELGESON
LONG TERM...13
AVIATION...13
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
932 AM CDT THU SEP 4 2014
.MORNING DISCUSSION UPDATE...
LATEST STREAMLINE ANALYSIS CONTINUES TO SHOW A HUMID FLOW PATTERN
IN THE LOWER LEVELS. NOT MUCH TO SPEAK OF AS FAR AS LOW LEVEL
DYNAMICS. BUT...THE MID AND UPPER LEVEL PATTERN SHOWS WEAK N-S
TROUGHING EXTENDING FROM THE NORTHERN GULF NORTHWARD ACROSS THE
MID STATE. MRH PROFILES SHOW A DEFINITIVE MOIST TO DRY GRADIENT
FROM EAST TO WEST. THIS WILL ALLOW CONVECTIVE PARAMETERS TO BE A
LITTLE MORE FAVORABLE ACROSS OUR EASTERN COUNTIES FOR TODAY.
LATEST HRRR IS IN LINE WITH THE CURRENT FCST AND SHOWS CONVECTION
DEVELOPING ACROSS OUR EASTERN COUNTIES AROUND OR SHORTLY BEFORE
NOON. QPF AVERAGES ACROSS THE EAST SHOULD BE ON THE LIGHT SIDE.
CAPES DON`T LOOK IMPRESSIVE ENOUGH TODAY TO SUPPORT ANY STRONG
ACTIVITY.
AS FOR TEMPERATURES...LATEST NUMERICAL GUIDANCE AND EXPECTED TEMPS
AT 15Z LOOK TO BE IN LINE WITH EXPECTED HIGHS.
NO UPDATED NEEDED FOR NOW OTHER THAN TO REISSUE AND REMOVE THE
MENTION OF FOG. STILL 3SM BR AT CKV BUT THIS SHOULD CONTINUE TO
IMPROVE. OTW...IF THE ONSET OF CONVECTION IS FURTHER WEST THAN
EXPECTED...WILL EXPAND THE WEATHER GRIDS A LITTLE FURTHER WESTWARD
IF NEEDED.
&&
.PREV DISCUSSION... /ISSUED 628 AM CDT THU SEP 4 2014/
UPDATE...FOR AVIATION.
AVIATION...
12Z TAFS...LOOKING FOR MAINLY VFR TODAY. DENSE FOG CURRENTLY AT
CKV WILL LIFT BY 14Z. SCT TSRA OVER THE PLATEAU THIS
AFTERNOON...SO INCLUDING VCTS FOR CSV. OTHERWISE...SCT CUMULUS
CLOUDS TODAY WITH S WINDS NEAR 6KT. PATCHY FOG EXPECTED
TONIGHT...MAINLY MVFR...BUT CKV COULD GO DOWN TO LIFR AGAIN.
13
PREV DISCUSSION... /ISSUED 308 AM CDT THU SEP 4 2014/
DISCUSSION...
FORECAST QUANDARIES...POTENTIAL FOR PATCHY DENSE FOG FORMATION
THIS MORNING... SHWR/TSTMS CHANCES...ANY MODEL TIMING DIFFERENCES
IN OVERALL WX PATTERN THIS WEEKEND...TEMPS.
AS THRU THE MID MORNING HRS FOR TODAY...WILL BE MONITORING THIS MORNING
PATCHY FOG FORMATION THRU AND AROUND PRESS TIME...WITH VSBYS ALREADY
BELOW ONE MILE IN SOME SELECTED LOCATIONS ACROSS SRN PORTIONS OF MID
STATE. THREE SCENARIOS COULD PLAY OUT...JUST MENTIONING PATCHY FOG THRU
THE MID MORNING HRS IN THE SUITE OF FORECAST PRODUCTS...POSSIBLE ISSUANCE
OF AN SPS DEALING WITH LOCALLY DENSE FOG FORMATION THRU MID MORNING
HRS...OR A DENSE FOG ADVISORY FOR A PORTIONS/ALL OF MID STATE. NO MATTER
WHAT...DEWPOINT DEPRESSIONS...CALM WINDS...AND CLRING SKIES ARE ALL
FAVORABLE THRU THE MID MORNING HRS FOR FOG FORMATION. KEY TO MORE WIDESPREAD
PATCHY TO DENSE FOG DEVELOPMENT ACROSS PLATEAU REGION WILL BE IF THERE
IS ANY BREAKS/EROSION OF CLOUD COVERAGE PRESENTLY ACROSS PLATEAU COUNTIES...
WHERE SHORT RANGE MODEL CONSENSUS ALONG WITH CURRENT SATELLITE TRENDS
SHOWING CURRENT CLOUD COVERAGE TRENDS AT LEAST GENERALLY MAINTAIN ITSELF
THRU THE MID MORNING HOURS. WILL BE WATCHING THIS CAREFULLY ON WHAT
DECISION TO DO CONCERNING FOG FORMATION OVER THIS PORTION OF THE MID
STATE. WHATEVER DECISION IS FINALLY MADE HERE...WILL ALSO HIGHLIGHT
IT IN THE MORNING`S HAZARDOUS WEATHER OUTLOOK.
AS FOR THE MID MORNING HRS TODAY THRU FRI NIGHT...MODEL CONSENSUS CONTINUES
TO SHOW RIDGING INFLUENCES SFC/ALOFT ALONG WITH A CONTINUANCE OF PLENTIFUL
LOW LEVEL MOISTURE INTERACTING WITH DIURNAL INFLUENCES AND LOCAL OROGRAPHIC
EFFECTS...RESULTING IN A TYPICAL SUMMERTIME PATTERN FOR THE MID STATE
THRU FRI WITH MAINLY LATE MORNING THRU EARLY EVENING SHWRS/TSTMS...WITH
THE BEST CHANCE OF SHWRS/TSTMS ACROSS ERN PORTIONS INCLUDING PLATEAU
REGION WHERE BEST OVERALL MOISTURE WILL CONTINUE TO BE USHERED INTO
MID STATE AREA PER THIS MOISTURE BEING ON PERIPHERY OF SFC BERMUDA
HIGH PRESSURE INFLUENCES. WILL ALSO CONTINUE LEANING TOWARD THE WARMER
GFS MOS SOLUTION ON HIGHS WITH THIS SUMMER TIME PATTERN...LOWER 90S...
MID TO UPPER 80S PLATEAU WITH LOWS AROUND 70...UPPER 60S PLATEAU. WILL
KEEP A SLIGHT CHANCE TO CHANCE OF SHWRS/TSTMS THRU FRI NIGHT AS MOISTURE
POOLS AND SHORTWAVE APPROACHES.
AS FOR THE WEEKEND INTO THE FIRST PART OF NEXT WEEK...STILL LOOKS LIKE
ANOTHER RATHER WEAK SFC FRONT IS EXPECTED TO PASS THRU THE MID STATE
AS SAT PROGRESSES WITH ANOTHER SHORTWAVE PASSAGE RESULTING IN SCT SHWRS/TSTMS
ACROSS THE MID STATE FROM AT LEAST THE LATE MORNING HRS THRU POSSIBLY
THE ENTIRE EVENING HRS. A GOOD MODEL CONSENSUS HAS BEEN REACHED WITH
THESE FEATURES NOW. ALSO...FROM TODAY THRU SAT...WOULD NOT BE SURPRISED
FOR A FEW TSTMS TO AT LEAST REACH STRONG THRESHOLDS...AND WILL MENTION
THIS IN THE MORNING HAZARDOUS WEATHER OUTLOOK ISSUANCE ALSO. MID-UPPER
MS RIVER VALLEY 1020MB SFC HIGH PRESSURE PATTERN WILL BEGIN INFLUENCING
THE MID STATE`S WEATHER BY SUN RESULTING IN A TREND BACK TOWARD TEMPS
BEING MORE AROUND SEASONABLE NORMAL VALUES. LATEST GFS MOS GUIDANCE
COMING MORE IN LINE WITH PREVIOUS RUNS OF THE EURO SOLUTION WITH TEMPS
NEAR SEASONABLE NORMAL VALUES THRU THE MID PORTION OF NEXT WEEK. WILL
CONTINUE WITH A SLIGHT CHANCE OF DIURNALLY DRIVEN SHWRS/TSTMS SUN INTO
MON AS QUASI ZONAL FLOW ALOFT AIDING IN PASSAGES OF ADDITIONAL SHORTWAVES
IN FLOW ALOFT. THERE ARE SOME TIMING DIFFERENCES BETWEEN THE LATEST
GFS/DGEX AND EURO IN WHEN POTENTIALLY MORE SIGNIFICANT SHORTWAVE PASSAGE
IS EXPECTED THRU THE MID PORTION OF NEXT WEEK...BUT WILL CONTINUE WITH
A GENERALLY TREND OF TREND TOWARD SCT SHWRS/TSTMS THRU WED AS SFC PATTERN
BECOMES MORE SLY ORIENTATED IN NATURE USHERING IN ADDITIONAL MOISTURE
TO MID STATE.
31
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
959 AM CDT THU SEP 4 2014
.UPDATE...
SHOWERS CONTINUE TO DIMINISH ACROSS SOUTHERN WISCONSIN THIS
MORNING. LATEST MESOSCALE MODELS CONTINUE TO SHOW THAT A CAPPED
ENVIRONMENT SHOULD RESULT IN DRY CONDITIONS FROM LATE MORNING
THROUGH THE AFTERNOON. ALSO...STILL THINK THAT THERE SHOULD BE
SOME SUNSHINE...WITH CLEARING ALREADY OCCURING IN THE LONE ROCK
AND WISCONSIN DELLS AREAS. MODELS ARE STILL SHOWING 925 MB TEMPS
IN THE 25-27C RANGE BY LATE AFTERNOON. GIVEN ENOUGH SUN...MOST
PLACES SHOULD APPROACH OR REACH 90 BY THE END OF THE DAY...SO WILL
LEAVE TEMPS AS IS FOR NOW.
STILL A LOT TO LOOK AT TO EVALUATE THE THUNDERSTORM POTENTIAL FOR
THIS EVENING AND OVERNIGHT. HOPEFULLY THE PICTURE WILL BECOME MORE
CLEAR AS 12Z MODELS ROLL IN.
&&
.AVIATION/18Z TAFS/...
SHOWERS CONTINUE TO DIMINISH ACROSS SOUTHERN WISCONSIN THIS
MORNING WITH DRY WEATHER EXPECTED FROM LATE MORNING THROUGH THE
AFTERNOON. STILL LOOKS A CHANCE FOR STORMS THIS EVENING AND
OVERNIGHT...THOUGH MODELS ARE NOT IN VERY GOOD AGREEMENT WITH THE
TIMING/PLACEMENT OF CONVECTION. HOPEFULLY THE PICTURE WILL BECOME MORE
CLEAR AS 12Z MODELS ROLL IN.
LOOKS LIKE SOME MORE LOW LEVEL WIND SHEAR IS POSSIBLE THIS EVENING
INTO TONIGHT AS WINDS EASE A BIT AT THE SURFACE AND THE LOW LEVEL
JET SITS OVERHEAD.
OTHER THAN LOWER VSBYS IN MODERATE TO HEAVY RAIN...EXPECT VFR
CONDITIONS TO CONTINUE THROUGH FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 228 AM CDT THU SEP 4 2014/
SHORT TERM...
TODAY...FORECAST CONFIDENCE IS MEDIUM.
THE SECONDARY CONVECTIVE DEVELOPMENT...TIED WITH THE H8 WARM FRONT
ON THE NOSE OF THE LOW LEVEL JET LEANING INTO THE AREA...IS
EXPANDING QUICKLY ACROSS SOUTHWEST WI AT THE TIME OF THIS WRITING.
FOR SOME REASON THE HRRR HAS DECIDED TO DUMP THIS DEVELOPMENT AND
WENT DRY WITH THE 04 AND 05Z UPDATES. WELL...THAT/S NOT GOING TO
WORK OUT.
SATELLITE IMAGERY IS SHOWING A LOWER MID DECK EXPANDING QUICKLY
UPSTREAM...HIGHLIGHTING THE CONVERGENCE OF WARM AND MOIST AIR ON THE
NOSE OF THAT H8 JET. MOST OF THE MODELS SHOW THIS DEVELOPMENT
OCCURRING EARLY THIS MORNING...EXITING BY MID TO LATE MORNING.
ISOLATED SEVERE STORMS ARE POSSIBLE WITH WIND AND HAIL THE MAIN
THREAT. THE RAIN WOULD BE HEAVY AND URBAN AND SMALL STREAM FLOODING
IS POSIBLE IF ANY STORMS TURN AWAY FROM THE FASTER MEAN FLOW.
ONCE THE STORMS MOVE OUT...WE GET INTO A VERY IMPRESSIVE THERMAL
RIDGE AHEAD OF AN APPROACHING COLD FRONT. 925MB TEMPS CLIMB TO AN
IMPRESSIVE 25-27C...IF WE GET ENOUGH SUNSHINE WE COULD SEE MANY
AREAS HIT THE 90 MARK. I/M COMFORTABLE KEEPING WHAT WE HAVE IN THE
FORECAST...WHICH IS ABOVE MOST GUIDANCE VALUES RIGHT NOW. THE
AIRMASS OVER US TODAY WILL BE VERY HUMID WITH DEW POINTS REACHING
THE LOWER 70S. THE HEAT INDEX WILL BE IN THE MID TO UPPER 90S.
THANKFULLY THIS IS SHORT LIVED AS THE COLD FRONT COMING THROUGH
TONIGHT WILL BRING MUCH COOLER TEMPS ON FRIDAY.
TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
A STRONG COLD FRONT WILL PUSH THROUGH THE AREA OVERNIGHT. IT/S A
RATHER LATE SHOW FOR SOUTHERN WISCONSIN AS THE FRONT DOESN/T REACH
MADISON UNTIL ABOUT 6 AM FRIDAY AND MILWAUKEE ABOUT 9 AM. THE
INITIAL DEVELOPMENT SHOULD OCCUR OVER ECNTRL MN AND WCNTRL WI THEN
EXPAND AND ORGANIZE ALONG THE FRONT WITH TIME...HEADING SOUTHEAST
INTO SOUTHERN WISCONSIN OVERNIGHT. THE AIRMASS WILL BE VERY MOIST
AHEAD OF THE FRONT...BUT THE LATE TIMING WILL BEGIN TO LIMIT
INSTABILITY OVER TIME. IN ADDITION...THE LOW LEVEL JET FOCUSES WELL
EAST OF WISCONSIN BY THE TIME THE FRONT ARRIVES. WOULD EXPECT A FEW
STORMS TO BECOME SEVERE NORTHWEST OF OUR FORECAST AREA...WHERE
STORMS INTITIATE...THEN AS THEY DRIFT SOUTH INTO THE FORECAST
AREA...THE INTENSITY WILL GRADUALLY DIMINISH. SPC HAS US IN A
SLIGHT RISK OF SEVERE STORMS NORTH OF A PORT WASHINGTON TO MADISON
TO DODGEVILLE LINE. THE FAR SOUTH WOULD STRUGGLE TO SEE SEVERE GIVEN
THE TIMING. THIS LOOKS VERY REASONABLE. THE MAIN THREAT WILL BE WIND
AND HAIL.
FRIDAY AND FRIDAY NIGHT...FORECAST CONFIDENCE MEDIUM.
THE SURFACE TO 850MB COLD FRONT WILL BE REACHING FAR SOUTHEAST WI
AROUND 12Z...WHICH IS LATER THAN THE PAST SEVERAL MODEL RUNS.
MEANWHILE... A STRONG MID LEVEL SHORTWAVE TROUGH WILL BE SLIDING
ACROSS THE UPPER MIDWEST. AHEAD OF THIS TROUGH... THERE WILL BE WEAK
SHORTWAVE ACTIVITY AND ALSO RISING MOTION IN THE RIGHT ENTRANCE
REGION OF AN UPPER JET. THE AREA JUST BEHIND THE SURFACE COLD FRONT
AND AHEAD OF THE UPPER TROUGH WILL LINE UP OVER SOUTHEAST WI DURING
THE DAY FRIDAY AND KEEP THE POSSIBILITY OF SHOWERS AND ISOLATED
THUNDERSTORMS GOING. THE LIMITING FACTOR FOR PRECIP IS A DRY LAYER
FROM 5 TO 10 KFT.
THE MODELS ARE MIXED ABOUT WHERE SHOWERS AND THUNDERSTORMS WILL
TRACK FRIDAY AFTERNOON. MOST SUGGEST THE MAIN FORCING AND PRECIP
WILL BE SOUTH OF THE WI/IL BORDER. THUS...WILL CONTINUE THE
DIMINISHING TREND FOR POPS ON FRIDAY AFTERNOON AND EVENING.
THERE SHOULD BE PLENTY OF CLOUDS OVER SOUTHERN WI ON FRIDAY.
THAT AND THE COLD AIR ADVECTION WILL LIMIT HIGHS TO THE MID 70S.
THE MID LEVEL SHORTWAVE TROUGH WILL EXIT SOUTHEAST WI BY AROUND
MIDNIGHT FRIDAY NIGHT. THIS WILL USHER MUCH DRIER AND COOLER AIR
INTO SOUTHERN WI WHICH WILL HANG AROUND THROUGH THE WHOLE WEEKEND
AND MONDAY.
LONG TERM...
SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE HIGH.
PLAN ON A QUIET STRETCH OF WEATHER FOR THE WEEKEND WITH LOW HUMIDITY
AND COOLER TEMPERATURES. HIGHS WILL BE IN THE LOWER TO MID 70S WITH
PLENTY OF SUNSHINE. LOWS WILL DROP DOWN INTO THE LOWER 50S...WITH
SATURDAY NIGHT LOOKING LIKE THE COOLEST. DEWPOINT DEPRESSIONS SHOULD
BE FAIRLY LOW WITH LIGHT WINDS...SO PATCHY FOG LOOKS POSSIBLE.
MONDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM.
THE ECMWF AND GFS ARE NOW OUT OF PHASE FOR THE NEXT WARM AIR ROUND
OF THUNDERSTORMS IMPACTING SOUTHERN WI MONDAY NIGHT AND TUESDAY.
THE GFS IS ROUGHLY 6 HOURS SLOWER WITH THE PRECIP AND HAS A
WEAKER- LOOKING SHORTWAVE TROUGH DUE TO THE EARLIER ARRIVAL OF AN
UPPER JET STREAK.
THEN THE TWO MODELS ARE BACK INTO GENERAL AGREEMENT ABOUT A BACK
DOOR COLD FRONT DROPPING DOWN THE LAKE INTO SOUTHERN WI LATE TUESDAY
NIGHT. THERE IS NOT MUCH FORCING FOR PRECIP...SO LOW CLOUDS AND
MAYBE A FEW SPRINKLES WOULD BE POSSIBLE THROUGH WED MORNING. THEN
THERE SHOULD BE A PERIOD OF QUIET WEATHER WITH EASTERLY WINDS OVER
SOUTHERN WI THROUGH WED NIGHT. THEREFORE...WENT WITH A LOWERING
TREND FOR POPS AND THUNDER IN THE FORECAST.
ANOTHER ROUND OF SHOWERS AND STORMS ARE POSSIBLE FOR SOUTHERN WI AS
A MID LEVEL TROUGH SLIDES FROM THE NORTHERN PLAINS TO THE GREAT
LAKES REGION LATE IN THE WEEK...THURSDAY THROUGH FRIDAY NIGHT.
THERE ARE STILL PLENTY OF MODEL DIFFERENCES THAT WILL NEED TO BE
IRONED OUT BEFORE DECIDING THE EXTENT OF THUNDER.
AVIATION/12Z TAFS/...
IN GENERAL...EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD.
HOWEVER...THERE ARE A COUPLE OF OPPORTUNITIES FOR LOWER CONDITIONS.
WE SHOULD SEE AT LEAST SCATTERED CONVECTION THIS MORNING AS A WARM
FRONT MOVES THROUGH. CONDITIONS WOULD DETERIORATE TO MVFR OR EVEN
IFR LEVELS IN ANY STRONGER STORMS. THINGS SHOULD CLEAR OUT BY LATE
MORNING AS HOT AIR ARRIVES AHEAD OF AN APPROACHING COLD FRONT. LOOK
FOR RATHER BREEZY CONDITIONS WITH A SOUTH TO SOUTHWEST WIND LATER
THIS MORNING AND AFTERNOON. THE COLD FRONT ARRIVES LATE
TONIGHT...REACHING MADISON AROUND 12Z FRIDAY AND KMKE/KUES/KENW
AROUND 15-16Z FRI. IT LOOKS LIKE THERE COULD BE A SHORT PERIOD OF
MVFR CIGS/VSBYS IN THE COLD AIR ADVECTION IN THE IMMEDIATE WAKE OF
THE FRONT. THUNDERSTORMS ARE ALSO POSSIBLE WITH THE FRONTAL PASSAGE
LATE TONIGHT.
MARINE...
SOUTH TO SOUTHWEST WINDS TODAY WILL GUST TO AROUND 25 KNOTS...SO A
SMALL CRAFT ADVISORY IS IN EFFECT FROM 10 AM TO 10 PM TODAY. WAVES
WILL INCREASE TO 3 TO 5 FEET THURSDAY...THE HIGHEST WAVES IN THE
NORTH.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
FRIDAY THROUGH WEDNESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
608 AM CDT THU SEP 4 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 326 AM CDT THU SEP 4 2014
SURFACE MAP AS OF 3 AM THIS MORNING HAD A DEEP 996MB LOW OVER
EASTERN SD WITH A WARM FRONT EXTENDING ACROSS SOUTHERN MN AND INTO
SOUTHWEST WI. CURRENTLY WATCHING ONE CLUSTER OF STRONG THUNDERSTORMS
DEPARTING THE AREA INTO NORTHEAST WI. WITHIN THE LAST 1/2 HOUR...A
CLUSTER OF SHOWERS AND THUNDERSTORMS POPPED UP OVER FAR NORTHEAST
IA/SOUTHWEST WI. FURTHER ANALYSIS SHOWING THESE SHOWERS AND STORMS
FORMING IN RESPONSE TO A NOSE OF STRONG 850MB MOISTURE TRANSPORT
WORKING NORTHEAST ACROSS IA...AND OCCURRING ABOVE A VERY STRONG 700-
750MB CAP OF 14C PER THE RAP BUFKIT AT BLUE RIVER WI. OTHERWISE...
TEMPERATURES ACROSS THE AREA EARLY THIS MORNING WERE IN THE 60S
ACROSS NORTH CENTRAL WI...AND IN THE 70S ELSEWHERE ACROSS THE ARX
FORECAST AREA.
WARM FRONT MAKES A PUSH NORTHEAST THROUGH THE REST OF THE AREA THIS
MORNING. THINKING THOSE SHOWERS/STORMS WILL SHOVE OUT OF THE AREA AS
CAP STRENGTHENS IN WARM SECTOR. WILL BE WATCHING AN MCS OVER ND
MAKING ITS WAY EAST-SOUTHEAST...WHICH COULD CLIP CLARK AND TAYLOR
COUNTIES AS IT MAKES ITS WAY ACROSS FAR NORTHERN WI/UPPER MI. MAY
HAVE TO ADJUST POPS ACCORDINGLY.
OTHERWISE...STRONG WARM AIR ADVECTION WILL TAKE PLACE ACROSS THE
AREA WITH STRENGTHENING 700-750MB CAP. THIS SHOULD HOLD OFF ANY
FURTHER CONVECTION AND PUSH TEMPERATURES WELL INTO THE 80S...TO A
FEW LOWER 90S ALONG/SOUTH OF I-90. DEW POINTS WILL ALSO BE
INCREASING INTO THE LOWER 70S THROUGH THE DAY...PRODUCING VERY
WARM/MUGGY/UNCOMFORTABLE CONDITIONS. HEAT INDICES FOR THE MOST PART
LOOK TO BE IN THE 90-100 RANGE...BUT COULD SEE A FEW HOURS OF 100-
105 IN A FEW SPOTS IN THE MISSISSIPPI/WISCONSIN RIVER VALLEYS. NOT
THINKING A HEAT ADVISORY WILL BE NEEDED AT THIS POINT DUE TO THE
BRIEF TOUCH IN THE CRITERIA RANGE. WILL HIT IT HARD WITH OUR OTHER
PRODUCTS.
CAP HOLDS STRONG INTO THE AFTERNOON HOURS AS A COLD FRONT PUSHES
SOUTHEASTWARD INTO NORTHERN WI/SOUTH CENTRAL MN. MODELS AT ODDS AT
HANDLING CONVECTION OR LACK THEREOF WHICH HEDGES ON STRENGTH OF
CAP...WHICH IS VERY STRONG FOR THIS TIME OF YEAR. GFS/ECMWF/CANADIAN
DETERMINISTIC MODELS ALL HOLD OFF DEVELOPING CONVECTION THROUGH 7PM.
NAM IS A BIT MORE GUNG-HO FIRING ALONG THE FRONT BASICALLY NORTH OF
I-94 BETWEEN 4-7PM. NMM/ARW WRF MODELS SIDE WITH THE NAM. REASON
BEING... BUFKIT SOUNDINGS REVEAL POSSIBLY SOME ELEVATED CONVECTION
BURBLING ABOVE THE CAP AS MID-LEVEL COOLING/STEEPENING LAPSE RATES
TAKE PLACE WITH INCOMING MID-LEVEL TROUGH. THIS WOULD COMPROMISE THE
CAP AND LET SURFACE BASED/DEEP CONVECTION RELEASE ALONG THE FRONT.
WILL HAVE TO KEEP AN EYE ON THIS FOR SEVERE WIND/HAIL POTENTIAL AS 0-
3KM BULK SHEAR IS PLENTIFUL IN THE 30-40KT RANGE ALONG WITH MUCAPE
IN THE 3000-4000J/KG RANGE.
THE COLD FRONT CONTINUES TO PUSH SOUTHEAST THROUGH THE AREA FRIDAY
NIGHT FOR CONTINUED THUNDERSTORM CHANCES. SOME OF THESE STORMS COULD
BE REMAIN SEVERE AT LEAST INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU SEP 4 2014
WITH THE COLD FRONT PUSHED INTO NORTHERN IL BY FRIDAY MORNING...
NORTHWEST WINDS WILL DRAW DRIER/COOLER AIR OVER THE FORECAST AREA.
EXPECTING FAIRLY BREEZY NORTHWEST WINDS IN THE 15-25MPH RANGE WITH
HIGHS ONLY TOPPING OFF IN THE UPPER 60S TO TO LOWER 70S.
MORE EARLY FALL-LIKE CONDITIONS ARE THEN EXPECTED INTO THE WEEKEND
AS CANADIAN HIGH PRESSURE DOMINATES THE CENTRAL CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. LOOK FOR MOSTLY CLEAR SKIES
THROUGH SUNDAY WITH HIGHS SATURDAY AND SUNDAY IN THE 70S AND
OVERNIGHT LOWS IN THE 40S TO LOWER 50S.
FOR MONDAY THROUGH WEDNESDAY...DEEPENING CYCLONIC FLOW OVER CANADA
AND NORTHERN CONUS WILL DRIVE A COUPLE TROUGHS THROUGH THE REGION FOR
A PERIOD OF UNSETTLED WEATHER WITH ON/OFF SHOWER AND THUNDERSTORM
CHANCES. TEMPERATURES ARE EXPECTED TO BE AT OR A FEW DEGREES BELOW
NORMAL WITH HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 608 AM CDT THU SEP 4 2014
MOISTURE TRANSPORT INTO THE REGION UNDERNEATH THE CAP HAS ALLOWED
AN AREA OF IFR/MVFR CEILINGS TO FORM OVER THE AREA. THE 04.09Z RAP
AND 04.06Z NAM SOUNDINGS SUGGEST THIS SHOULD PERSIST INTO THE
MIDDLE OF THE MORNING BEFORE DISSIPATING AND WITH THE CAP OVER THE
AREA...CONDITIONS SHOULD GO UP TO HIGH VFR CEILINGS. THE COLD
FRONT OVER WESTERN MINNESOTA WILL PUSH INTO THE AREA STARTING LATE
THIS AFTERNOON WITH INIDATIONS THAT THE CAP WILL START TO BREAK TO
ALLOW MORE STORMS TO BEGIN DEVELOPING. WILL HAVE VCTS FOR A GOOD
SHARE OF THE EVENING WITH A TWO HOUR TEMPO GROUP BASED ON THE
04.00Z HI-RES ARW WHEN THE STORMS ARE MOST PROBABLE TO MOVE
ACROSS THE TAF SITES WITH MVFR AND POSSIBLY IFR CONDITIONS
POSSIBLE. THE FRONT WILL THEN COME THROUGH IN THE OVERNIGHT HOURS
SWINGING THE WINDS AROUND TO THE NORTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
315 PM MST THU SEP 4 2014
...UPDATED AVIATION AND FIRE WEATHER...
.SYNOPSIS...
INCREASING SOUTHERLY FLOW ALOFT WILL CONTINUE TO GRADUALLY INCREASE
MOISTURE LEVELS OVER THE DESERT SOUTHWEST THROUGH FRIDAY...WITH
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OVER THE REGION. A
FURTHER INCREASE IN MOISTURE IS EXPECTED THIS WEEKEND AS MOISTURE
FROM THE REMAINS OF HURRICANE NORBERT SURGES INLAND INTO THE
REGION...WITH HEAVY RAIN AND LOCALIZED FLOODING POSSIBLE. A SLOW
DRYING TREND IS THEN EXPECTED TO BEGIN NEXT WEEK AS HIGH PRESSURE
SLOWLY REBUILDS OVER THE REGION.
&&
.DISCUSSION...
TONIGHT AND FRIDAY...
MODELS CONTINUE TO BE CONSISTENT ON THE FORECAST THROUGH
FRIDAY...WITH A SLOW INCREASE IN THE PWAT VALUES OVER AZ TONIGHT
INTO EARLY FRIDAY...MOST LIKELY INTO THE 1.50-1.60 INCH RANGE. THIS
MODEST MOISTURE...COMBINED WITH A WEAK SHORTWAVE THAT IS NOW SEEN IN
THE LATEST WV SATELLITE IMAGERY MOVING INTO EXTREME SOUTHERN AZ...IS
NOW TRIGGERING ISOLATED TO SCATTERED THUNDERSTORMS OVER PIMA COUNTY.
THE LATEST HRRR HI-RES MODEL RUN IS NOW SHOWING MOST OF THESE STORMS
REMAINING TO THE SOUTH OF OUR CWA...BUT WITH A FEW OF THE STORMS
MOVING INTO OR DEVELOPING OVER SOUTH-CENTRAL AZ. THE MAIN THREAT
FROM THESE STORMS WILL BE GUSTY WINDS AND BLOWING DUST...WITH ONLY A
SLIGHT CHANCE FOR MEASURABLE RAIN AT ANY ONE SPOT.
FRIDAY STILL LOOKS LIKE A BIT OF A DOWN DAY...WITH THE LATEST GFS
PRETTY MUCH MATCHING EARLIER RUNS...WITH WEAK HIGH PRESSURE RIDGING
REBUILDING INTO THE REGION FROM THE WEST AND PWATS FALLING A
BIT...INTO THE 1.40-1.50 INCH RANGE...WHICH SHOULD KEEP TS ACTIVITY
LIMITED TO SOUTH-CENTRAL AZ...MOSTLY OVER THE HIGHER TERRAIN NORTH
AND EAST OF PHOENIX.
SATURDAY THROUGH MONDAY...
THIS PERIOD LOOKS MORE-AND-MORE LIKELY THAT IT WILL BE A QUITE
ACTIVE...AS MOISTURE FROM HURRICANE NORBERT BEGINS TO IMPACT THE
REGION. THE LATEST (21Z) NHC FORECAST CONTINUES TO TRACK THIS STORM
TO THE WEST OF THE BAJA CALIFORNIA PENINSULA OVER THE NEXT 3-5
DAYS...WITH AN UPPER TROF THAT WILL BE MOVING SOUTHWARD ALONG THE
NORTHERN AND CENTRAL CA COAST SHEARING MID AND HIGH-LEVEL MOISTURE
NORTHWESTWARD INTO OUR REGION FROM THIS STORM. LATEST MODEL RUNS
ALSO ARE SHOWING A BROAD AREA OF LOW-LEVEL SOUTHEASTERLY FLOW
PUSHING VERY MOIST AIR NORTHWARD ACROSS THE GULF OF CALIFORNIA INTO
AZ AND SE CA...WITH SFC DEWPOINTS EXCEEDING 70F AT ANY LOWER DESERT
LOCATIONS BY SUNDAY MORNING AND PWATS RISING WELL ABOVE 2
INCHES...WHICH IS AT NEAR-RECORD VALUES FOR EARLY SEPT.
GIVEN THESE VERY HIGH AVAILABLE MOISTURE LEVELS...WIDESPREAD
SHOWER/THUNDERSTORM ACTIVITY NOW APPEARS TO BE VERY LIKELY FROM LATE
SAT INTO MONDAY...WITH HEAVY RAIN AND LOCALIZED FLOODING BEING THE
MAIN THREATS FROM STORM-TOTAL RAINFALL AMOUNTS OF 1-2 INCHES...OR
EVEN MORE AT MANY LOWER DESERT LOCATIONS. THE RAIN AND CLOUDS ARE
ALSO EXPECTED TO COOL TEMPS SUBSTANTIALLY DURING THIS PERIOD...WITH
HIGHS REMAINING IN THE 90S...AND EVEN A FEW 80S ACROSS THE LOWER
DESERTS EACH DAY.
TUESDAY THROUGH THURSDAY...
A SLOW DRYING TREND IS EXPECTED THROUGH THIS PERIOD AS INCREASING
WESTERLY FLOW AND BUILDING HIGH PRESSURE OVER THE REGION HELPS TO
SWEEP ANY REMAINING MOISTURE FROM NORBERT WELL OFF TO OUR
EAST...WITH THE THREAT OF THUNDERSTORM ACTIVITY LIKELY ENDING OVER
OUR CWA BY WEDNESDAY OR THURSDAY...WITH DAYTIME HIGHS REBOUNDING TO
NEAR...OR SLIGHTLY ABOVE NORMAL VALUES.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
OVERALL FORECAST CONFIDENCE (ESPECIALLY TIMING OF WIND SHIFTS) IS
LOWER THAN NORMAL THROUGH TONIGHT. ISOLATED THUNDERSTORMS SHOULD
REMAIN BOTH WELL SOUTH AND NORTH OF TERMINALS THROUGH
TONIGHT...HOWEVER BRIEF PERIODS OF GUSTY OUTFLOW WINDS MAY AFFECT
THE AIRFIELDS EARLY THIS EVENING. HAVE INDICATED A WIND SHIFT
EARLIER THAN USUAL...BUT BELOW ANY OPERATIONAL IMPACT. THERE IS AN
OUTSIDE CHANCE OF STRONGER WIND GUSTS AND BLOWING DUST...HOWEVER
UNCERTAINTY IS TOO HIGH TO INCLUDE IN THE TAF PACKAGE. ONLY PERIODIC
MIDLEVEL CLOUDS AOA 9K FT AND LIGHT EAST WINDS ARE LIKELY AFTER
MIDNIGHT.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES SHOULD PREVAIL THROUGH FRIDAY MORNING...THOUGH
SOME INCREASE IN A SCT LOWER DECK...AS WELL AS HIGH DECK MAY BE
POSSIBLE. WIND DIRECTION FORECASTS ARE OF LOWER CONFIDENCE AS
OUTFLOW WINDS AND SOUTHERLY SURGES OF MOISTURE MAY BRING STRONGER
GUSTS EVEN DURING OVERNIGHT HOURS. IN GENERAL...A SOUTHERLY OR
SOUTHEASTERLY COMPONENT WILL BE FAVORED.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
MOISTURE WILL ALREADY HAVE ENVELOPED SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA BY SUNDAY...WITH THE POTENTIAL FOR HEAVY RAINFALL OVER
MUCH OF THE REGION. STORM CHANCES WILL CONTINUE THROUGH TUESDAY
BEFORE TRENDING DOWNWARD THROUGH MIDWEEK. HUMIDITIES WILL REMAIN
VERY ELEVATED DURING THE ENTIRE PERIOD...ONLY FALLING INTO A 30-40
PERCENT RANGE IN THE AFTERNOON WITH MOSTLY COOLER THAN AVERAGE
TEMPERATURES. WINDS MAY BE GUSTY IN AND AROUND THUNDERSTORMS...AND
STAY VARIABLE FOR PROLONGED PERIODS OTHERWISE.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA
AVIATION...MO
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
240 PM MST THU SEP 4 2014
&&
.SYNOPSIS...
INCREASING SOUTHERLY FLOW ALOFT WILL CONTINUE TO GRADUALLY INCREASE
MOISTURE LEVELS OVER THE DESERT SOUTHWEST THROUGH FRIDAY...WITH
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LIKELY OVER THE
REGION. A FURTHER INCREASE IN MOISTURE IS EXPECTED THIS WEEKEND AS
MOISTURE FROM THE REMAINS OF HURRICANE NORBERT SURGES INLAND INTO
THE REGION...WITH HEAVY RAIN AND LOCALIZED FLOODING POSSIBLE. A SLOW
DRYING TREND IS THEN EXPECTED TO BEGIN NEXT WEEK AS HIGH PRESSURE
SLOWLY REBUILDS OVER THE REGION.
&&
.DISCUSSION...
TONIGHT AND FRIDAY...
MODELS CONTINUE TO BE CONSISTENT ON THE FORECAST THROUGH
FRIDAY...WITH A SLOW INCREASE IN THE PWAT VALUES OVER AZ TONIGHT
INTO EARLY FRIDAY...MOST LIKELY INTO THE 1.50-1.60 INCH RANGE. THIS
MODEST MOISTURE...COMBINED WITH A WEAK SHORTWAVE THAT IS NOW SEEN IN
THE LATEST WV SATELLITE IMAGERY MOVING INTO EXTREME SOUTHERN AZ...IS
NOW TRIGGERING ISOLATED TO SCATTERED THUNDERSTORMS OVER PIMA COUNTY.
THE LATEST HRRR HI-RES MODEL RUN IS NOW SHOWING MOST OF THESE STORMS
REMAINING TO THE SOUTH OF OUR CWA...BUT WITH A FEW OF THE STORMS
MOVING INTO OR DEVELOPING OVER SOUTH-CENTRAL AZ. THE MAIN THREAT
FROM THESE STORMS WILL BE GUSTY WINDS AND BLOWING DUST...WITH ONLY A
SLIGHT CHANCE FOR MEASURABLE RAIN AT ANY ONE SPOT.
FRIDAY STILL LOOKS LIKE A BIT OF A DOWN DAY...WITH THE LATEST GFS
PRETTY MUCH MATCHING EARLIER RUNS...WITH WEAK HIGH PRESSURE RIDGING
REBUILDING INTO THE REGION FROM THE WEST AND PWATS FALLING A
BIT...INTO THE 1.40-1.50 INCH RANGE...WHICH SHOULD KEEP TS ACTIVITY
LIMITED TO SOUTH-CENTRAL AZ...MOSTLY OVER THE HIGHER TERRAIN NORTH
AND EAST OF PHOENIX.
SATURDAY THROUGH MONDAY...
THIS PERIOD LOOKS MORE-AND-MORE LIKELY THAT IT WILL BE A QUITE
ACTIVE...AS MOISTURE FROM HURRICANE NORBERT BEGINS TO IMPACT THE
REGION. THE LATEST (21Z) NHC FORECAST CONTINUES TO TRACK THIS STORM
TO THE WEST OF THE BAJA CALIFORNIA PENINSULA OVER THE NEXT 3-5
DAYS...WITH AN UPPER TROF THAT WILL BE MOVING SOUTHWARD ALONG THE
NORTHERN AND CENTRAL CA COAST SHEARING MID AND HIGH-LEVEL MOISTURE
NORTHWESTWARD INTO OUR REGION FROM THIS STORM. LATEST MODEL RUNS
ALSO ARE SHOWING A BROAD AREA OF LOW-LEVEL SOUTHEASTERLY FLOW
PUSHING VERY MOIST AIR NORTHWARD ACROSS THE GULF OF CALIFORNIA INTO
AZ AND SE CA...WITH SFC DEWPOINTS EXCEEDING 70F AT ANY LOWER DESERT
LOCATIONS BY SUNDAY MORNING AND PWATS RISING WELL ABOVE 2
INCHES...WHICH IS AT NEAR-RECORD VALUES FOR EARLY SEPT.
GIVEN THESE VERY HIGH AVAILABLE MOISTURE LEVELS...WIDESPREAD
SHOWER/THUNDERSTORM ACTIVITY NOW APPEARS TO BE VERY LIKELY FROM LATE
SAT INTO MONDAY...WITH HEAVY RAIN AND LOCALIZED FLOODING BEING THE
MAIN THREATS FROM STORM-TOTAL RAINFALL AMOUNTS OF 1-2 INCHES...OR
EVEN MORE AT MANY LOWER DESERT LOCATIONS. THE RAIN AND CLOUDS ARE
ALSO EXPECTED TO COOL TEMPS SUBSTANTIALLY DURING THIS PERIOD...WITH
HIGHS REMAINING IN THE 90S...AND EVEN A FEW 80S ACROSS THE LOWER
DESERTS EACH DAY.
TUESDAY THROUGH THURSDAY...
A SLOW DRYING TREND IS EXPECTED THROUGH THIS PERIOD AS INCREASING
WESTERLY FLOW AND BUILDING HIGH PRESSURE OVER THE REGION HELPS TO
SWEEP ANY REMAINING MOISTURE FROM NORBERT WELL OFF TO OUR
EAST...WITH THE THREAT OF THUNDERSTORM ACTIVITY LIKELY ENDING OVER
OUR CWA BY WEDNESDAY OR THURSDAY...WITH DAYTIME HIGHS REBOUNDING TO
NEAR...OR SLIGHTLY ABOVE NORMAL VALUES.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
ISOLATED SHOWERS/THUNDERSTORMS EXPECTED ACROSS SOUTH-CENTRAL ARIZONA
THIS MORNING...MAINLY ACROSS HIGHER TERRAIN AREAS TO THE NORTH AND
EAST OF PHOENIX...WITH SCT-BKN CLOUD DECKS AOA 10KFT. WINDS WILL
CONTINUE TO FAVOR EAST-SOUTHEAST GENERALLY 10KT OR LESS...AND MAY
SWITCH TO SOUTHWEST BRIEFLY FOR A COUPLE HOURS IF THERE IS
SUFFICIENT CLEARING OF MID-LEVEL CLOUD DECKS LATE THIS AFTERNOON.
ISOLATED SHOWER/THUNDERSTORMS ACTIVITY ENCROACHES ONCE AGAIN NEAR
TERMINALS THIS EVENING...BUT UNCERTAINTY IN TIMING/COVERAGE
WARRANTS LEAVING ANY MENTION OF WEATHER OUT OF THE TAFS AT THIS
TIME.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE TODAY...WITH MOSTLY
CLEAR SKIES AND JUST A FEW-SCT MID LEVEL CUMULUS. WINDS SHOULD
CONTINUE TO FAVOR SOUTH-SOUTHEAST GENERALLY 10KT OR LESS...EXCEPT
ALONG THE LOWER COLORADO RIVER VALLEY/NEAR KBLH WHERE GUSTS UP TO
25KT WILL ACCOMPANY ADDITIONAL MOISTURE SURGE AFTER 06Z FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
MONSOON MOISTURE WILL CONTINUE TO INCREASE AND SPREAD NORTH AND WEST
REACHING THE LOWER DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA BY SATURDAY. STORM CHANCES WILL CONTINUE THROUGH TUESDAY
BEFORE TRENDING DOWNWARD LATE IN THE PERIOD. HUMIDITIES WILL REMAIN
ELEVATED DURING THE PERIOD...WHILE TEMPERATURES TREND DOWNWARD.
WINDS WILL FOLLOW FAMILIAR SUMMERTIME SLOPE-VALLEY PATTERNS BUT WITH
SIGNIFICANT DISRUPTIONS DUE TO THUNDERSTORM ACTIVITY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA
AVIATION...MEYERS
FIRE WEATHER...AJ/MEYERS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
441 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA THROUGH TONIGHT WILL SHIFT OFFSHORE
FRIDAY INTO FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE
WEST. THE COLD FRONT WILL MOVE ACROSS ON SATURDAY...THEN HIGH
PRESSURE WILL BUILD INTO THE NORTHEAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SCT-BKN CU OVER INTERIOR SECTIONS NORTH/WEST OF NYC AND ALONG THE
SEA BREEZE FRONT ON LONG ISLAND SHOULD DISSIPATE THIS EVENING...
LEAVING MAINLY CLEAR SKIES FOR THE REST OF TONIGHT. BOTH THE 12Z
NAM AND 17Z RAP ARE SHOWING LOW STRATUS AND/OR FOG DEVELOPMENT
TOWARD DAYBREAK CLOSE TO LONG ISLAND VIA INCREASED LOW LEVEL
MOISTURE IN ONSHORE FLOW AND COOLING BENEATH A SFC-BASED
INVERSION. ATTM SUSPECT NAM LOW LEVEL MOISTURE IS OVERDONE...SO
HAVE SIDED MORE WITH THE RAP WITH AT LEAST PTCLDY SKIES THERE
LATE. EXPECT LOWS IN THE UPPER 50S IN THE LONG ISLAND PINE BARRENS
AND SOME INTERIOR VALLEYS...60S MOST ELSEWHERE...AND LOWER 70S IN
NYC.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
EXPECT MAINLY DRY WX AS THE HIGH SHIFTS OFFSHORE. PRESENCE OF A
WEAK SFC TROUGH IN THE WAKE OF THE DEPARTING HIGH...WEAK LOW LEVEL
WAA...AND APPROACH OF MID LEVEL SHORTWAVES FROM THE WEST AND
SOUTHWEST MAY SPARK ISOLD SHOWERS LATE FRI NIGHT. WITH CONTINUED
ONSHORE FLOW THERE SHOULD BE A BETTER CHANCE FOR LOW CLOUDS AND
FOG TO DEVELOP LATE AT NIGHT.
TEMPS ON FRI WITH ONSHORE FLOW AND MORE IN THE WAY OF CLOUDS
SHOULD BE CLOSE TO OR ONLY SLIGHTLY LOWER THAN THOSE OF
TODAY...WITH UPPER 70S FOR COASTAL SE CT AND 80S ELSEWHERE.
LOWS FRI NIGHT SHOULD BE IN THE MID/UPPER 60S INLAND...AND LOWER
70S IN NYC METRO AND LONG ISLAND.
THERE IS A LOW RISK OF RIP CURRENTS AT THE OCEAN BEACHES FOR
MOST OF FRIDAY...BUT IT MAY BECOME BRIEFLY MODERATE LATE IN THE
DAY AND EVENING WITH SEABREEZE DEVELOPMENT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
DEEP SW FLOW WILL USHER A HOT AND HUMID AIR MASS AHEAD OF A COLD
FRONT ACROSS THE REGION ON SATURDAY WITH SFC DEW POINTS CLIMBING TO
NEAR 70 AND HIGH TEMPS IN THE UPPER 80S TO AROUND 90. THIS WILL
RESULT IN A HEAT INDEX IN THE LOWER TO MID 90S. IN ADDITION...PW
WILL APPROACH 2 INCHES. AS A RESULT...AS COLD FRONT APPROACHES
FROM THE WEST...THERE WILL BE SUFFICIENT ENERGY AND MOISTURE FOR
SHOWERS AND THUNDERSTORMS...WITH ACTIVITY INCREASING THROUGH THE
AFTERNOON. HEAVY RAIN...GUSTY WINDS...AND HAIL WILL BE POSSIBLE
WITH THE STRONGER STORMS. WILL KEEP POPS CAPPED AT LIKELY FOR
NOW...IN LINE WITH THE LATEST MODEL GUIDANCE.
COLD FRONT PUSHES THROUGH THE REGION FROM WEST TO EAST SATURDAY
NIGHT...AND SHOWERS/THUNDERSTORMS WILL TAPER OFF TOWARDS DAYBREAK
SUNDAY. A MUCH DRYER AIR MASS BUILDS INTO THE REGION WITH SFC
DEWPOINTS DROPPING INTO THE 50S BY SUNDAY AFTERNOON...AND HIGHS WILL
FALL TO LEVELS A FEW DEGREES BELOW NORMAL...IN THE MID TO UPPER 70S.
HIGH PRES BUILDS INTO THE REGION MONDAY AND TUESDAY WITH DRY
CONDS...AND THEN MOVES OFFSHORE TUESDAY NIGHT. AS LOW PRES OVER THE
MIDWEST APPROACHES...A WARM FRONT WILL LIFT NORTH INTO THE REGION ON
WEDNESDAY. UNSETTLED WEATHER POSSIBLE FOR WEDNESDAY AND THURSDAY OF
NEXT WEEK. TEMPS WILL AVERAGE TO NEAR NORMAL LEVELS DURING THIS
TIME....GENERALLY IN THE 70S.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE SLIDES OFFSHORE TONIGHT.
MAINLY VFR THROUGH THE TAF PERIOD AT AREA TERMINALS. SEA BREEZE WILL
AFFECT ALL BUT KSWF THROUGH THIS EVENING. THE FLOW THEN BECOMES
LIGHT SSW-SW THROUGHOUT...THEN LIGHT AND VARIABLE THROUGHOUT BY
AROUND MIDNIGHT TONIGHT.
THERE IS THE POSSIBILITY OF MVFR FOG MOVING IN FOR ISOLATED AREAS
OUTSIDE THE CITY TERMINALS...MAINLY FOR KSWF AND KHPN. AS OF RIGHT
NOW HOWEVER...DO NOT THINK IT WILL BE PREVAILING. THERE IS A LOW
CHANCE THAT IT CAN MAKE ITS WAY INTO KEWR. TIMING OF ANY FOG WOULD
BE 09Z OR AFTER...AND BURN OFF AN HOUR OR TWO AFTER SUNRISE
FRIDAY...THROUGH 13Z.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KLGA FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KEWR FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
KHPN FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. TEMPO BR LIMITING VIS TO 5SM OR LOWER
BETWEEN 09Z AND 13Z.
KISP FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRIDAY AFTN...MAINLY VFR. ISOLD SHRA/TSTM POSSIBLE N/W OF CITY
TERMINALS.
.FRIDAY NIGHT...MVFR OR LOWER POSSIBLE IN ANY LOW CLOUDS AND/OR
FOG. SLIGHT CHANCE SHRA/TSTM W OF CITY TERMINALS.
.SATURDAY TO SATURDAY NIGHT...MVFR OR LOWER POSSIBLE IN SCT-
NUMEROUS SHRA/TSTMS. LOW CLOUDS AND/OR FOG POSSIBLE EARLY IN THE
MORNING. SW-W WINDS G20+ KT POSSIBLE SATURDAY...SHIFTING TO THE
NW-N SATURDAY NIGHT.
.SUNDAY-MONDAY...VFR. E WINDS G20KT POSSIBLE IN THE AFTERNOON ON
MONDAY.
.TUE...VFR.
&&
.MARINE...
DEPARTING HIGH PRESSURE WILL KEEP SUB-SCA CONDITIONS IN PLACE
THROUGH FRI NIGHT.
OCNL GUSTS TO 25 KT ARE POSSIBLE ON SAT AS THE PRES GRADIENT
TIGHTENS WITH THE APPROACH AND PASSAGE OF A COLD FRONT. HIGH PRES
THEN BUILDS OVER THE WATERS FOR THE START OF THE NEW WEEK.
A PERSISTENT EASTERLY FLOW WILL DEVELOP ON THE WATERS...POSSIBLY
PUSHING OCEAN SEAS CLOSE TO SCA LEVELS BY THE MIDDLE OF THE NEW
WORK WEEK.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS ARE LIKELY SAT INTO SAT NIGHT.
STRONGER STORMS COULD PRODUCE HEAVY RAIN AND LOCALIZED FLOODING
OF URBAN/POOR DRAINAGE AREAS AND SMALL STREAMS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GOODMAN/MPS
NEAR TERM...GOODMAN/MPS
SHORT TERM...GOODMAN
LONG TERM...MPS
AVIATION...JP
MARINE...GOODMAN/MPS
HYDROLOGY...MPS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
434 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA THROUGH TONIGHT WILL SHIFT OFFSHORE
FRIDAY INTO FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE
WEST. THE COLD FRONT WILL MOVE ACROSS ON SATURDAY...THEN HIGH
PRESSURE WILL BUILD INTO THE NORTHEAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SCT-BKN CU OVER INTERIOR SECTIONS NORTH/WEST OF NYC AND ALONG THE
SEA BREEZE FRONT ON LONG ISLAND SHOULD DISSIPATE THIS EVENING...
LEAVING MAINLY CLEAR SKIES FOR THE REST OF TONIGHT. BOTH THE 12Z
NAM AND 17Z RAP ARE SHOWING LOW STRATUS AND/OR FOG DEVELOPMENT
TOWARD DAYBREAK CLOSE TO LONG ISLAND VIA INCREASED LOW LEVEL
MOISTURE IN ONSHORE FLOW AND COOLING BENEATH A SFC-BASED
INVERSION. ATTM SUSPECT NAM LOW LEVEL MOISTURE IS OVERDONE...SO
HAVE SIDED MORE WITH THE RAP WITH AT LEAST PTCLDY SKIES THERE
LATE. EXPECT LOWS IN THE UPPER 50S IN THE LONG ISLAND PINE BARRENS
AND SOME INTERIOR VALLEYS...60S MOST ELSEWHERE...AND LOWER 70S IN
NYC.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
EXPECT MAINLY DRY WX AS THE HIGH SHIFTS OFFSHORE. PRESENCE OF A
WEAK SFC TROUGH IN THE WAKE OF THE DEPARTING HIGH...WEAK LOW LEVEL
WAA...AND APPROACH OF MID LEVEL SHORTWAVES FROM THE WEST AND
SOUTHWEST MAY SPARK ISOLD SHOWERS LATE FRI NIGHT. WITH CONTINUED
ONSHORE FLOW THERE SHOULD BE A BETTER CHANCE FOR LOW CLOUDS AND
FOG TO DEVELOP LATE AT NIGHT.
TEMPS ON FRI WITH ONSHORE FLOW AND MORE IN THE WAY OF CLOUDS
SHOULD BE CLOSE TO OR ONLY SLIGHTLY LOWER THAN THOSE OF
TODAY...WITH UPPER 70S FOR COASTAL SE CT AND 80S ELSEWHERE.
LOWS FRI NIGHT SHOULD BE IN THE MID/UPPER 60S INLAND...AND LOWER
70S IN NYC METRO AND LONG ISLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
DEEP SW FLOW WILL USHER A HOT AND HUMID AIR MASS AHEAD OF A COLD
FRONT ACROSS THE REGION ON SATURDAY WITH SFC DEW POINTS CLIMBING TO
NEAR 70 AND HIGH TEMPS IN THE UPPER 80S TO AROUND 90. THIS WILL
RESULT IN A HEAT INDEX IN THE LOWER TO MID 90S. IN ADDITION...PW
WILL APPROACH 2 INCHES. AS A RESULT...AS COLD FRONT APPROACHES
FROM THE WEST...THERE WILL BE SUFFICIENT ENERGY AND MOISTURE FOR
SHOWERS AND THUNDERSTORMS...WITH ACTIVITY INCREASING THROUGH THE
AFTERNOON. HEAVY RAIN...GUSTY WINDS...AND HAIL WILL BE POSSIBLE
WITH THE STRONGER STORMS. WILL KEEP POPS CAPPED AT LIKELY FOR
NOW...IN LINE WITH THE LATEST MODEL GUIDANCE.
COLD FRONT PUSHES THROUGH THE REGION FROM WEST TO EAST SATURDAY
NIGHT...AND SHOWERS/THUNDERSTORMS WILL TAPER OFF TOWARDS DAYBREAK
SUNDAY. A MUCH DRYER AIR MASS BUILDS INTO THE REGION WITH SFC
DEWPOINTS DROPPING INTO THE 50S BY SUNDAY AFTERNOON...AND HIGHS WILL
FALL TO LEVELS A FEW DEGREES BELOW NORMAL...IN THE MID TO UPPER 70S.
HIGH PRES BUILDS INTO THE REGION MONDAY AND TUESDAY WITH DRY
CONDS...AND THEN MOVES OFFSHORE TUESDAY NIGHT. AS LOW PRES OVER THE
MIDWEST APPROACHES...A WARM FRONT WILL LIFT NORTH INTO THE REGION ON
WEDNESDAY. UNSETTLED WEATHER POSSIBLE FOR WEDNESDAY AND THURSDAY OF
NEXT WEEK. TEMPS WILL AVERAGE TO NEAR NORMAL LEVELS DURING THIS
TIME....GENERALLY IN THE 70S.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE SLIDES OFFSHORE TONIGHT.
MAINLY VFR THROUGH THE TAF PERIOD AT AREA TERMINALS. SEA BREEZE WILL
AFFECT ALL BUT KSWF THROUGH THIS EVENING. THE FLOW THEN BECOMES
LIGHT SSW-SW THROUGHOUT...THEN LIGHT AND VARIABLE THROUGHOUT BY
AROUND MIDNIGHT TONIGHT.
THERE IS THE POSSIBILITY OF MVFR FOG MOVING IN FOR ISOLATED AREAS
OUTSIDE THE CITY TERMINALS...MAINLY FOR KSWF AND KHPN. AS OF RIGHT
NOW HOWEVER...DO NOT THINK IT WILL BE PREVAILING. THERE IS A LOW
CHANCE THAT IT CAN MAKE ITS WAY INTO KEWR. TIMING OF ANY FOG WOULD
BE 09Z OR AFTER...AND BURN OFF AN HOUR OR TWO AFTER SUNRISE
FRIDAY...THROUGH 13Z.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KLGA FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KEWR FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
KHPN FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. TEMPO BR LIMITING VIS TO 5SM OR LOWER
BETWEEN 09Z AND 13Z.
KISP FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRIDAY AFTN...MAINLY VFR. ISOLD SHRA/TSTM POSSIBLE N/W OF CITY
TERMINALS.
.FRIDAY NIGHT...MVFR OR LOWER POSSIBLE IN ANY LOW CLOUDS AND/OR
FOG. SLIGHT CHANCE SHRA/TSTM W OF CITY TERMINALS.
.SATURDAY TO SATURDAY NIGHT...MVFR OR LOWER POSSIBLE IN SCT-
NUMEROUS SHRA/TSTMS. LOW CLOUDS AND/OR FOG POSSIBLE EARLY IN THE
MORNING. SW-W WINDS G20+ KT POSSIBLE SATURDAY...SHIFTING TO THE
NW-N SATURDAY NIGHT.
.SUNDAY-MONDAY...VFR. E WINDS G20KT POSSIBLE IN THE AFTERNOON ON
MONDAY.
.TUE...VFR.
&&
.MARINE...
DEPARTING HIGH PRESSURE WILL KEEP SUB-SCA CONDITIONS IN PLACE
THROUGH FRI NIGHT.
OCNL GUSTS TO 25 KT ARE POSSIBLE ON SAT AS THE PRES GRADIENT
TIGHTENS WITH THE APPROACH AND PASSAGE OF A COLD FRONT. HIGH PRES
THEN BUILDS OVER THE WATERS FOR THE START OF THE NEW WEEK.
A PERSISTENT EASTERLY FLOW WILL DEVELOP ON THE WATERS...POSSIBLY
PUSHING OCEAN SEAS CLOSE TO SCA LEVELS BY THE MIDDLE OF THE NEW
WORK WEEK.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS ARE LIKELY SAT INTO SAT NIGHT.
STRONGER STORMS COULD PRODUCE HEAVY RAIN AND LOCALIZED FLOODING
OF URBAN/POOR DRAINAGE AREAS AND SMALL STREAMS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GOODMAN/MPS
NEAR TERM...GOODMAN/MPS
SHORT TERM...GOODMAN
LONG TERM...MPS
AVIATION...JP
MARINE...GOODMAN/MPS
HYDROLOGY...MPS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
345 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA THROUGH TONIGHT WILL SHIFT OFFSHORE
FRIDAY INTO FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE
WEST. THE COLD FRONT WILL MOVE ACROSS ON SATURDAY...THEN HIGH
PRESSURE WILL BUILD INTO THE NORTHEAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SCT-BKN CU OVER INTERIOR SECTIONS NORTH/WEST OF NYC AND ALONG THE
SEA BREEZE FRONT ON LONG ISLAND SHOULD DISSIPATE THIS EVENING...
LEAVING MAINLY CLEAR SKIES FOR THE REST OF TONIGHT. BOTH THE 12Z
NAM AND 17Z RAP ARE SHOWING LOW STRATUS AND/OR FOG DEVELOPMENT
TOWARD DAYBREAK CLOSE TO LONG ISLAND VIA INCREASED LOW LEVEL
MOISTURE IN ONSHORE FLOW AND COOLING BENEATH A SFC-BASED
INVERSION. ATTM SUSPECT NAM LOW LEVEL MOISTURE IS OVERDONE...SO
HAVE SIDED MORE WITH THE RAP WITH AT LEAST PTCLDY SKIES THERE
LATE. EXPECT LOWS IN THE UPPER 50S IN THE LONG ISLAND PINE BARRENS
AND SOME INTERIOR VALLEYS...60S MOST ELSEWHERE...AND LOWER 70S IN
NYC.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
EXPECT MAINLY DRY WX AS THE HIGH SHIFTS OFFSHORE. PRESENCE OF A
WEAK SFC TROUGH IN THE WAKE OF THE DEPARTING HIGH...WEAK LOW LEVEL
WAA...AND APPROACH OF MID LEVEL SHORTWAVES FROM THE WEST AND
SOUTHWEST MAY SPARK ISOLD SHOWERS LATE FRI NIGHT. WITH CONTINUED
ONSHORE FLOW THERE SHOULD BE A BETTER CHANCE FOR LOW CLOUDS AND
FOG TO DEVELOP LATE AT NIGHT.
TEMPS ON FRI WITH ONSHORE FLOW AND MORE IN THE WAY OF CLOUDS
SHOULD BE CLOSE TO OR ONLY SLIGHTLY LOWER THAN THOSE OF
TODAY...WITH UPPER 70S FOR COASTAL SE CT AND 80S ELSEWHERE.
LOWS FRI NIGHT SHOULD BE IN THE MID/UPPER 60S INLAND...AND LOWER
70S IN NYC METRO AND LONG ISLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
DEEP SW FLOW WILL USHER A HOT AND HUMID AIR MASS AHEAD OF A COLD
FRONT ACROSS THE REGION ON SATURDAY WITH SFC DEW POINTS CLIMBING TO
NEAR 70 AND HIGH TEMPS IN THE UPPER 80S TO AROUND 90. THIS WILL
RESULT IN A HEAT INDEX IN THE LOWER TO MID 90S. IN ADDITION...PW
WILL APPROACH 2 INCHES. AS A RESULT...AS COLD FRONT APPROACHES
FROM THE WEST...THERE WILL BE SUFFICIENT ENERGY AND MOISTURE FOR
SHOWERS AND THUNDERSTORMS...WITH ACTIVITY INCREASING THROUGH THE
AFTERNOON. HEAVY RAIN...GUSTY WINDS...AND HAIL WILL BE POSSIBLE
WITH THE STRONGER STORMS. WILL KEEP POPS CAPPED AT LIKELY FOR
NOW...IN LINE WITH THE LATEST MODEL GUIDANCE.
COLD FRONT PUSHES THROUGH THE REGION FROM WEST TO EAST SATURDAY
NIGHT...AND SHOWERS/THUNDERSTORMS WILL TAPER OFF TOWARDS DAYBREAK
SUNDAY. A MUCH DRYER AIR MASS BUILDS INTO THE REGION WITH SFC
DEWPOINTS DROPPING INTO THE 50S BY SUNDAY AFTERNOON...AND HIGHS WILL
FALL TO LEVELS A FEW DEGREES BELOW NORMAL...IN THE MID TO UPPER 70S.
HIGH PRES BUILDS INTO THE REGION MONDAY AND TUESDAY WITH DRY
CONDS...AND THEN MOVES OFFSHORE TUESDAY NIGHT. AS LOW PRES OVER THE
MIDWEST APPROACHES...A WARM FRONT WILL LIFT NORTH INTO THE REGION ON
WEDNESDAY. UNSETTLED WEATHER POSSIBLE FOR WEDNESDAY AND THURSDAY OF
NEXT WEEK. TEMPS WILL AVERAGE TO NEAR NORMAL LEVELS DURING THIS
TIME....GENERALLY IN THE 70S.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE OVER THE AREA THIS MORNING...SLIDES OFFSHORE INTO
TONIGHT.
VFR THROUGH THE TAF PERIOD AT AREA TERMINALS. SEA BREEZE HAS
ALREADY MOVED THROUGH CITY TERMINALS AND WILL AFFECT ALL BUT KSWF
TODAY WHERE A LIGHT SW FLOW HAS DEVELOPED. FLOW BECOMES LIGHT OUT
OF THE SSW-SW THROUGHOUT BY EARLY EVENING...THEN LIGHT AND
VARIABLE THROUGHOUT BY AROUND MIDNIGHT TONIGHT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KLGA FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KEWR FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
KHPN FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. TEMPO BR LIMITING VIS TO 5SM OR LOWER
BETWEEN 09Z AND 13Z.
KISP FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
.FRIDAY...MVFR FOG POSSIBLE INLAND TERMINALS EARLY. ISOLD
SHRA/TSTM POSSIBLE N/W OF CITY TERMINALS.
.FRIDAY NIGHT...MVFR OR LOWER POSSIBLE IN ANY LOW CLOUDS AND/OR
FOG. SLIGHT CHANCE SHRA/TSTM W OF CITY TERMINALS.
.SATURDAY TO SATURDAY NIGHT...MVFR OR LOWER POSSIBLE IN SCT-
NUMEROUS SHRA/TSTMS. LOW CLOUDS AND/OR FOG POSSIBLE EARLY IN THE
MORNING. SW-W WINDS G20+ KT POSSIBLE SATURDAY...SHIFTING TO THE
NW-N SATURDAY NIGHT.
.SUNDAY-MONDAY...VFR. E WINDS G20KT POSSIBLE IN THE AFTERNOON ON
MONDAY.
.TUE...VFR.
&&
.MARINE...
DEPARTING HIGH PRESSURE WILL KEEP SUB-SCA CONDITIONS IN PLACE
THROUGH FRI NIGHT.
OCNL GUSTS TO 25 KT ARE POSSIBLE ON SAT AS THE PRES GRADIENT
TIGHTENS WITH THE APPROACH AND PASSAGE OF A COLD FRONT. HIGH PRES
THEN BUILDS OVER THE WATERS FOR THE START OF THE NEW WEEK.
A PERSISTENT EASTERLY FLOW WILL DEVELOP ON THE WATERS...POSSIBLY
PUSHING OCEAN SEAS CLOSE TO SCA LEVELS BY THE MIDDLE OF THE NEW
WORK WEEK.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS ARE LIKELY SAT INTO SAT NIGHT.
STRONGER STORMS COULD PRODUCE HEAVY RAIN AND LOCALIZED FLOODING
OF URBAN/POOR DRAINAGE AREAS AND SMALL STREAMS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GOODMAN/MPS
NEAR TERM...GOODMAN/MPS
SHORT TERM...GOODMAN
LONG TERM...MPS
AVIATION...JP
MARINE...GOODMAN/MPS
HYDROLOGY...MPS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
238 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA THROUGH TONIGHT WILL SHIFT OFFSHORE
FRIDAY INTO FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE
WEST. THE COLD FRONT WILL MOVE ACROSS THE AREA FROM SATURDAY AND
SATURDAY NIGHT. HIGH PRESSURE WILL THEN BUILD IN FROM SUNDAY INTO
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SCT CU OVER INTERIOR SECTIONS NORTH/WEST OF NYC AND ALONG THE SEA
BREEZE FRONT ON LONG ISLAND SHOULD DISSIPATE TONIGHT...LEAVING
MAINLY CLEAR SKIES. BOTH THE 12Z NAM AND 17Z RAP ARE SHOWING LOW
STRATUS AND/OR FOG DEVELOPMENT TOWARD DAYBREAK CLOSE TO LONG
ISLAND VIA INCREASED LOW LEVEL MOISTURE IN ONSHORE FLOW AND
COOLING BENEATH A SFC-BASED INVERSION. ATTM SUSPECT NAM LOW LEVEL
MOISTURE IS OVERDONE...SO HAVE SIDED MORE WITH THE RAP WITH AT
LEAST PTCLDY SKIES THERE LATE. EXPECT LOWS IN THE UPPER 50S IN THE
LONG ISLAND PINE BARRENS AND SOME INTERIOR VALLEYS...60S MOST
ELSEWHERE...AND LOWER 70S IN NYC.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
EXPECT MAINLY DRY WX AS THE HIGH SHIFTS OFFSHORE. PRESENCE OF A
WEAK SFC TROUGH IN THE WAKE OF THE DEPARTING HIGH...WEAK LOW LEVEL
WAA...AND APPROACH OF MID LEVEL SHORTWAVES FROM THE WEST AND
SOUTHWEST MAY SPARK ISOLD SHOWERS LATE FRI NIGHT. WITH CONTINUED
ONSHORE FLOW THERE SHOULD BE A BETTER CHANCE FOR LOW CLOUDS AND
FOG TO DEVELOP LATE AT NIGHT.
TEMPS ON FRI WITH ONSHORE FLOW AND MORE IN THE WAY OF CLOUDS
SHOULD BE CLOSE TO OR ONLY SLIGHTLY LOWER THAN THOSE OF
TODAY...WITH UPPER 70S FOR COASTAL SE CT AND 80S ELSEWHERE.
LOWS FRI NIGHT SHOULD BE IN THE MID/UPPER 60S INLAND...AND LOWER
70S IN NYC METRO AND LONG ISLAND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
POPS INCREASE RATHER QUICKLY DURING THE DAY SATURDAY AS THE COLD
FRONT MOVES INTO THE REGION. MODELS ARE IN GENERAL AGREEMENT ON
THE TIMING OF THE SURFACE FEATURES...WITH THE 00Z GFS CONTINUING
TO BE A LITTLE ON THE QUICK SIDE. EVEN THOUGH THE GFS IS A LITTLE
QUICKER THAN THE OTHER 00Z MODELS...THEY ALL HAVE THE
PRECIPITATION ENDING EARLY SUNDAY MORNING. WILL CONTINUE TO KEEP
LIKELY POPS IN FOR SATURDAY AND SATURDAY NIGHT ACROSS THE AREA.
ALSO...WITH INSTABILITY ACROSS THE REGION...EXPECT THUNDER TO ALSO
BE LIKELY WITH THE FRONT. GUSTY WINDS AND HEAVY RAIN WILL BE
POSSIBLE WITH ANY STRONGER STORMS.
THE FRONT MOVES EAST OF THE REGION SUNDAY MORNING WITH HIGH
PRESSURE BUILDING INTO THE REGION...ALLOWING CONDITIONS TO DRY
OUT. NORTHERLY FLOW WILL BECOME MORE NE/E DURING THE FIRST HALF
OF THE WEEK...WITH CONDITIONS FAIRLY COOLER THAN THIS WEEK. MOST
AREAS WILL BE AT OR BELOW NORMAL...GENERALLY IN THE 70S.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE OVER THE AREA THIS MORNING...SLIDES OFFSHORE INTO
TONIGHT.
VFR THROUGH THE TAF PERIOD AT AREA TERMINALS. SEA BREEZE HAS
ALREADY MOVED THROUGH CITY TERMINALS AND WILL AFFECT ALL BUT KSWF
TODAY WHERE A LIGHT SW FLOW HAS DEVELOPED. FLOW BECOMES LIGHT OUT
OF THE SSW-SW THROUGHOUT BY EARLY EVENING...THEN LIGHT AND
VARIABLE THROUGHOUT BY AROUND MIDNIGHT TONIGHT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KLGA FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
KEWR FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. LOW CHANCE OF TEMPO BR LIMITING VIS TO 6SM
BETWEEN 10Z AND 13Z.
KHPN FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES. TEMPO BR LIMITING VIS TO 5SM OR LOWER
BETWEEN 09Z AND 13Z.
KISP FCSTER COMMENTS: WIND DIRECTION WITH SEA BREEZE COULD VARY
+/- 20 TO 30 DEGREES.
.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
.FRIDAY...MAINLY VFR. MVFR FOG POSSIBLE INLAND TERMINALS EARLY. ISOLD
SHRA/TSTM POSSIBLE N/W OF CITY TERMINALS.
.FRIDAY NIGHT...MVFR OR LOWER POSSIBLE IN ANY LOW CLOUDS AND/OR
FOG. SLIGHT CHANCE SHRA/TSTM W OF CITY TERMINALS.
.SATURDAY TO SATURDAY NIGHT...MVFR OR LOWER POSSIBLE IN SCT-
NUMEROUS SHRA/TSTMS. LOW CLOUDS AND/OR FOG POSSIBLE EARLY IN THE
MORNING. SW-W WINDS G20+ KT POSSIBLE SATURDAY...SHIFTING TO THE
NW-N SATURDAY NIGHT.
.SUNDAY-MONDAY...VFR. E WINDS G20KT POSSIBLE IN THE AFTERNOON ON
MONDAY.
.TUE...VFR.
&&
.MARINE...
DEPARTING HIGH PRESSURE KEEP SUB-SCA CONDITIONS IN PLACE THROUGH
FRIDAY NIGHT.
WINDS AND SEAS WILL INCREASE WITH SW FLOW SATURDAY AHEAD OF AN
APPROACHING COLD FRONT. HOWEVER...THEY LOOK TO REMAIN BELOW SCA
CRITERIA AT THIS TIME. THE FRONT PASSES ACROSS THE WATERS SATURDAY
NIGHT...WITH SHOWERS AND THUNDERSTORMS FORECAST. NORTHERLY FLOW THEN
TAKES OVER SUNDAY INTO MONDAY...WITH CONDITIONS REMAINING BELOW SCA
CRITERIA.
&&
.HYDROLOGY...
NO SIGNIFICANT HYDROLOGIC ISSUES ARE EXPECTED THROUGH FRIDAY NIGHT.
SHOWERS AND THUNDERSTORMS ARE FORECAST SATURDAY INTO SATURDAY
NIGHT. WHILE WIDESPREAD HEAVY RAIN IS NOT ANTICIPATED...ANY STRONGER
STORM WILL BE CAPABLE OF PRODUCING BRIEF HEAVY RAINFALL RATES.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BC/SEARS
NEAR TERM...GOODMAN
SHORT TERM...SEARS
LONG TERM...BC
AVIATION...JP
MARINE...GOODMAN
HYDROLOGY...BC/SEARS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1257 PM CDT THU SEP 4 2014
.DISCUSSION...
1240 PM CDT
PERSISTENT CONVECTION IS FINALLY STARTING TO WANE EARLY THIS
AFTERNOON BUT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
LINGER FOR ANOTHER HOUR OR SO. EXCEPT IN AREAS GETTING MORE SUN
THAN RAIN SO FAR TODAY...HIGHS ARE ONCE AGAIN THIS YEAR GOING TO
HAVE TROUBLE GETTING QUITE UP TO INITIAL EXPECTATIONS...BUT A WARM
AND HUMID AFTERNOON IS STILL LIKELY WITH DEWPOINTS IN THE 70S AND
TEMPERATURES RECOVERING INTO THE 80S. FORECAST GRIDS ARE ADJUSTED
ACCORDINGLY AND AN UPDATED SET OF ZONES WAS SENT EARLIER THIS
HOUR.
LENNING
&&
.PREVIOUS DISCUSSION...
327 AM CDT
MORNING THUNDERSTORM COVERAGE AND DURATION ALONG WITH IMPACT ON
DAYTIME TEMPERATURES ARE THE SHORT TERM CHALLENGES. THUNDER
CHANCES AND DEGREE OF COOL DOWN ARE THE MAIN LONG TERM POINTS OF
EMPHASIS TODAY.
SHORT TERM...TODAY AND TONIGHT...
AN ACTIVE ELEVATED WARM AND MOIST ADVECTION ZONE SUPPORTING AREAS
OF CONVECTION IS OVER THE REGION EARLY THIS MORNING. A SHORT WAVE
DISTURBANCE IN EASTERN IA AS OF 330 AM HAS BEEN AN INSTIGATOR FOR
MORE ORGANIZED CONVECTION OVER THE DVN CWA. A BROAD BUT STRONG
45KT LOW-LEVEL JET IS ADVECTING IN MOIST AIR AT THE BASE OF
STEEPENING MID-LEVEL LAPSE RATES OF 7-8 C/KM. THIS WILL REMAIN
SUPPORTIVE OF WIDESPREAD CONVECTIVE UPDRAFTS THROUGH 8-9 AM
BEFORE A PROBABLE DIMINISHING TREND AS STORMS APPROACH/MOVE OVER
CHICAGO AND THE I-55 CORRIDOR. A RAP ANALYSIS INDICATES FAIRLY
SHORT CORFIDI PROPAGATION VECTORS WITH NORTHWEST MID-LEVEL FLOW
PERPENDICULAR TO THE LLJ. SO ISOLATED HEAVY RAIN CONCERNS WILL BE
PRESENT AND HAVE BEEN SUPPORTED ON REGIONAL RADAR TRENDS. HAVE
INCREASED QPF IN TANDEM WITH HIGHER POPS THROUGH MID-MORNING.
A STRENGTHENING CAP ALONG WITH THE WEAKENING/EXIT OF THE
AFOREMENTIONED SHORT WAVE SHOULD LIMIT ANY CONVECTIVE CHANCES THIS
AFTERNOON. HOWEVER...SOME CLOUDS MAY LINGER INTO EARLY AFTERNOON.
WITH THAT AND SOME COMMUNITIES SEEING A SLOWER WARMING TREND
EARLY THIS MORNING WITH CLOUDS AND RAIN...HAVE LOWERED
TEMPERATURES IN THE NORTHEAST HALF OF THE FORECAST AREA BY A
COUPLE DEGREES. TEMPERATURES SHOULD STILL REALIZE 90 IN FAR
WESTERN/SOUTHWESTERN AREAS BASED ON 850/925MB TEMPERATURE
CLIMATOLOGY AND SUPPORT FROM PAST SIMILAR EVENTS PER THE CIPS
ANALOGS. HEAT INDEX READINGS IN THIS AREA...FROM BYRON TO GIBSON
CITY AND WESTWARD...WILL LIKELY APPROACH 100 DEGREES DUE TO
FORECAST LOWER 70 DEW POINTS.
A QUIET AND MILD EVENING IS EXPECTED. CONFIDENCE FOR PRECIP
REMAINING OUT OF THE AREA OVERNIGHT IS LOW. WHILE FRONTAL
CONVERGENCE REMAINS OFF TO THE NORTHWEST...QUITE A BIT OF
ELEVATED INSTABILITY WILL BE PRESENT AND OVERALL FORCING FOR
PRECIP IS LOW. BUT AS WE HAVE SEEN EARLY THIS MORNING...EVEN A
SUBTLE WAVE CAN CAUSE PROBLEMS. SO CONTINUE CHANCE POPS.
MTF
LONG TERM FRIDAY THROUGH WEDNESDAY...
THE MAIN FORECAST CONCERNS DURING THE LONG TERM PERIOD FOCUS ON THE
THREAT FOR SHOWERS AND THUNDERSTORMS...SOME POSSIBLY STRONG...AND
THE THREAT OF HEAVY RAINFALL FRIDAY AND FRIDAY NIGHT.
SURFACE LOW PRESSURE CURRENTLY ACROSS THE EASTERN DAKOTAS WILL
SHIFT NORTHEASTWARD TO NEAR JAMES BAY BY THE START OF THE PERIOD
(FRIDAY MORNING). THIS LOW WILL DRIVE A COLD FRONT SOUTHWARD OVER
NORTHERN ILLINOIS BY EARLY FRIDAY AFTERNOON. THE TIMING OF THIS
FRONTAL PASSAGE SHOULD ALLOW THE HEAT AND HUMIDITY TO LINGER...AT
LEAST FOR THE FIRST HALF OF THE DAY...ESPECIALLY ACROSS MY SOUTHERN
AREAS. THEREFORE...HIGHS ON FRIDAY LOOK TO ONCE AGAIN CREEP NEAR THE
90 DEGREE MARK...WITH HEAT INDICIES OF 95 TO 100 SOUTH OF INTERSTATE
80.
THUNDERSTORMS WILL LIKELY FIRE ACROSS FAR NORTHERN ILLINOIS EARLY ON
FRIDAY AS THE FRONT APPROACHES...AND LIKELY INCREASE IN AREAL
COVERAGE BY FRIDAY AFTERNOON. SURFACE BASED STORMS APPEAR
LIKELY...AHEAD OF THE FRONTAL BOUNDARY LATER FRIDAY MORNING AND INTO
THE AFTERNOON...WITH THE PREFRONTAL HIGH THETA-E LOWER LEVEL AIR MASS
EXPECTED TO INDUCE MLCAPES OF 2000-3000 J/KG. ALTHOUGH DEEP LAYER
SHEAR WILL BE SOMEWHAT LACKLUSTER...WITH ONLY AROUND 25 KT OF 0-6 KM
BULK SHEAR...THERE WILL BE A SMALL THREAT FOR MULTI-CELL CLUSTERS
CAPABLE OF PRODUCE STRONG WINDS. HOWEVER...IT APPEAR THE MAIN THREAT
FOR THIS MAY REMAIN SOUTH OF THE CHICAGO AND ROCKFORD AREAS.
THE OTHER THREAT WITH THESE STORMS...AS HAS BEEN THE CASE WITH
STORMS FOR THE LAST FEW WEEKS...IS VERY HEAVY RAINFALL. THE HIGH
THETA E AIR MASS FEATURING PWAT VALUES OF 1.8 TO 2 INCHES WILL LEAD
TO VERY EFFICIENT RAINFALL RATES...AND THIS COUPLED WITH THE FACT
THAT THE STEERING LAYER FLOW LOOKS TO RUN NEARLY PARALLEL TO THE
SURFACE FRONTAL ZONE...TRAINING CELLS ARE A GOOD POSSIBILITY. IT
ALSO APPEARS THAT SHOWERS...POSSIBLY WITH SOME EMBEDDED ELEVATED
THUNDERSTORMS...WILL LIKELY CONTINUE IN THE WAKE OF THE SURFACE
BOUNDARY INTO FRIDAY NIGHT AS AN ANA-LIKE FRONTAL PRECIP EVENT SETS
UP. MID LEVEL FGEN AND THE PROXIMATELY TO THE RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET ALL POINT TO CONTINUED FORCING TO SUPPORT
PRECIP INTO FRIDAY NIGHT.
GIVEN THE POSSIBILITIES OF A PERIOD OF VERY HEAVY RAINFALL...WITH
POSSIBLE TRAINING OF CELLS AHEAD OF THE FRONT...FOLLOWED BY A LONGER
PERIOD OF MODERATE PRECIP INTO FRIDAY NIGHT...HYDRO ISSUES COULD
BECOME A CONCERN.
THINGS QUIET DOWN AND BECOME MUCH COOLER FOR THE WEEKEND UNDER
NORTHERN FLOW. HIGH TEMPERATURES BY SATURDAY AND SUNDAY LOOK TO BE
IN THE LOW TO MID 70S. OVERNIGHT TEMPERATURES INTO SUNDAY MORNING
LOOKS TO BE QUITE CHILLY AS A SURFACE HIGH BUILDS OVERHEAD. THIS
LOOKS TO SET UP WIDESPREAD LOWER 50 DEGREE TEMPERATURES OUTSIDE OF
CHICAGO...WITH EVEN A FEW UPPER 40 DEGREE READINGS POSSIBLE IN THE
WESTERN SUBURBS.
TEMPERATURES LOOK TO MODERATE A BIT BACK INTO THE UPPER 70S INTO
NEXT WEEK. THE NEXT CHANCE FOR STORMS LOOKS TO ENTER THE PICTURE
AGAIN BY LATE MONDAY NIGHT AND TUESDAY AS ANOTHER DISTURBANCE TAKES
AIM ON THE AREA.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SHRA/TSRA TRENDS...OVERALL DECREASING RAPIDLY.
* WIND SPEEDS AND DIRECTIONS NEAR LINGERING TSRA.
* MORE TSRA POSSIBLE TOMORROW.
LENNING
//DISCUSSION...UPDATED 18Z...
TSRA HAS MOSTLY MOVED SOUTH OF THE TERMINALS AS ANTICIPATED BUT A
FEW LINGERING SHOWERS AND ISOLATED STORMS REMAIN IN THE AREA.
COVERAGE HAS BEEN DECREASING RAPIDLY HOWEVER SO ONLY CARRIED AN
HOUR OR SO IN THE START OF THE TAFS. WINDS OVERALL REMAIN
SOUTHERLY BUT SOME LOCATIONS ARE SEEING BRIEF STRONG GUSTS AND
SHARP DIRECTIONAL CHANGES. OPTED TO GO WITH THE PREVAILING TREND
IN THE TAF RATHER THAN CHASE TRANSIENT AND UNPREDICTABLE LOCAL
EFFECTS.
AFTER A BRIEF PERIOD OF BACKING THIS AFTERNOON...VERY GRADUAL
VEERING IN THE WINDS SHOULD BE THE TREND THROUGH THE EVENING
INTO TOMORROW AHEAD OF AN APPROACHING COLD FRONT. MODELS HAVE THIS
FRONT REACHING THE LOCAL AREA TOWARD MID DAY TOMORROW...SO HAVE
TIMED PRECIP CHANCES TO MATCH THE ARRIVAL OF CONVERGENCE EFFECTS
ALONG THIS BOUNDARY.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN ALL ELEMENTS EXCEPT FOR PRECIP
TIMING TOMORROW.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHANCE OF SHRA AND SLIGHT CHANCE OF TSRA.
SATURDAY...VFR. NORTHEAST WINDS.
SUNDAY-MONDAY...VFR.
TUESDAY-WEDNESDAY...CHANCE OF TSRA.
MTF
&&
.MARINE...
155 AM CDT
THE WEATHER PATTERN ACROSS THE GREAT LAKES REGION WILL BE A BIT
ACTIVE OVER THE NEXT FEW DAYS...WITH SOME PERIODS OF STRONG WINDS IN
THE 25 TO 30 KT RANG...ALONG WITH A PERIOD OR TWO OF SHOWERS AND
STORMS.
A RATHER POTENT EARLY AUTUMN SEASON SURFACE LOW WILL MOVE FROM THE
EASTERN DAKOTAS EARLY THIS MORNING TO NEAR JAMES BAY BY EARLY FRIDAY
MORNING. THIS SYSTEM WILL CONTINUE TO INDUCE SOME STRONG SOUTHERN
WINDS OVER THE LAKE TODAY AND TONIGHT. IT APPEARS THE STRONGEST
WINDS UP TO AROUND 30 KT WILL OCCUR THIS EVENING ACROSS THE NORTHERN
HALF OF THE LAKE...WITH 20 TO 25 KT SOUTHERLY WINDS OVER THE
SOUTHERN HALF OF THE LAKE. THESE STRONG WINDS WILL RESULT IN SMALL
CRAFT ADVISORY CONDITIONS INTO THIS EVENING.
AS THE LOW SHIFTS OVER THE JAMES BAY FRIDAY MORNING...A TRAILING COLD
FRONT WILL SHIFT DOWN THE LAKE DURING THE DAY FRIDAY. WINDS WILL
SHIFT NORTHERLY INTO 15 TO 25 KT RANGE LATER FRIDAY AND INTO
SATURDAY...BEFORE ABATING LATER SATURDAY AS AN AREA OF SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN LAKES REGION. THESE NORTHERLY
WINDS DOWN THE FETCH OF LAKE MICHIGAN MAY AGAIN RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT AND SATURDAY...WITH WAVES
POSSIBLY IN THE 4 TO 7 FT RANGE.
THE WEATHER CONDITIONS LOOK TO QUIET DOWN FOR A COUPLE DAYS FOR
SUNDAY AND INTO EARLY NEXT WEEK AS SURFACE HIGH PRESSURE DOMINATES
ACROSS THE LAKES REGION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM THURSDAY.
&&
$$
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
1121 AM CDT THU SEP 4 2014
.DISCUSSION...
327 AM CDT
MORNING THUNDERSTORM COVERAGE AND DURATION ALONG WITH IMPACT ON
DAYTIME TEMPERATURES ARE THE SHORT TERM CHALLENGES. THUNDER
CHANCES AND DEGREE OF COOL DOWN ARE THE MAIN LONG TERM POINTS OF
EMPHASIS TODAY.
SHORT TERM...TODAY AND TONIGHT...
AN ACTIVE ELEVATED WARM AND MOIST ADVECTION ZONE SUPPORTING AREAS
OF CONVECTION IS OVER THE REGION EARLY THIS MORNING. A SHORT WAVE
DISTURBANCE IN EASTERN IA AS OF 330 AM HAS BEEN AN INSTIGATOR FOR
MORE ORGANIZED CONVECTION OVER THE DVN CWA. A BROAD BUT STRONG
45KT LOW-LEVEL JET IS ADVECTING IN MOIST AIR AT THE BASE OF
STEEPENING MID-LEVEL LAPSE RATES OF 7-8 C/KM. THIS WILL REMAIN
SUPPORTIVE OF WIDESPREAD CONVECTIVE UPDRAFTS THROUGH 8-9 AM
BEFORE A PROBABLE DIMINISHING TREND AS STORMS APPROACH/MOVE OVER
CHICAGO AND THE I-55 CORRIDOR. A RAP ANALYSIS INDICATES FAIRLY
SHORT CORFIDI PROPAGATION VECTORS WITH NORTHWEST MID-LEVEL FLOW
PERPENDICULAR TO THE LLJ. SO ISOLATED HEAVY RAIN CONCERNS WILL BE
PRESENT AND HAVE BEEN SUPPORTED ON REGIONAL RADAR TRENDS. HAVE
INCREASED QPF IN TANDEM WITH HIGHER POPS THROUGH MID-MORNING.
A STRENGTHENING CAP ALONG WITH THE WEAKENING/EXIT OF THE
AFOREMENTIONED SHORT WAVE SHOULD LIMIT ANY CONVECTIVE CHANCES THIS
AFTERNOON. HOWEVER...SOME CLOUDS MAY LINGER INTO EARLY AFTERNOON.
WITH THAT AND SOME COMMUNITIES SEEING A SLOWER WARMING TREND
EARLY THIS MORNING WITH CLOUDS AND RAIN...HAVE LOWERED
TEMPERATURES IN THE NORTHEAST HALF OF THE FORECAST AREA BY A
COUPLE DEGREES. TEMPERATURES SHOULD STILL REALIZE 90 IN FAR
WESTERN/SOUTHWESTERN AREAS BASED ON 850/925MB TEMPERATURE
CLIMATOLOGY AND SUPPORT FROM PAST SIMILAR EVENTS PER THE CIPS
ANALOGS. HEAT INDEX READINGS IN THIS AREA...FROM BYRON TO GIBSON
CITY AND WESTWARD...WILL LIKELY APPROACH 100 DEGREES DUE TO
FORECAST LOWER 70 DEW POINTS.
A QUIET AND MILD EVENING IS EXPECTED. CONFIDENCE FOR PRECIP
REMAINING OUT OF THE AREA OVERNIGHT IS LOW. WHILE FRONTAL
CONVERGENCE REMAINS OFF TO THE NORTHWEST...QUITE A BIT OF
ELEVATED INSTABILITY WILL BE PRESENT AND OVERALL FORCING FOR
PRECIP IS LOW. BUT AS WE HAVE SEEN EARLY THIS MORNING...EVEN A
SUBTLE WAVE CAN CAUSE PROBLEMS. SO CONTINUE CHANCE POPS.
MTF
LONG TERM FRIDAY THROUGH WEDNESDAY...
THE MAIN FORECAST CONCERNS DURING THE LONG TERM PERIOD FOCUS ON THE
THREAT FOR SHOWERS AND THUNDERSTORMS...SOME POSSIBLY STRONG...AND
THE THREAT OF HEAVY RAINFALL FRIDAY AND FRIDAY NIGHT.
SURFACE LOW PRESSURE CURRENTLY ACROSS THE EASTERN DAKOTAS WILL
SHIFT NORTHEASTWARD TO NEAR JAMES BAY BY THE START OF THE PERIOD
(FRIDAY MORNING). THIS LOW WILL DRIVE A COLD FRONT SOUTHWARD OVER
NORTHERN ILLINOIS BY EARLY FRIDAY AFTERNOON. THE TIMING OF THIS
FRONTAL PASSAGE SHOULD ALLOW THE HEAT AND HUMIDITY TO LINGER...AT
LEAST FOR THE FIRST HALF OF THE DAY...ESPECIALLY ACROSS MY SOUTHERN
AREAS. THEREFORE...HIGHS ON FRIDAY LOOK TO ONCE AGAIN CREEP NEAR THE
90 DEGREE MARK...WITH HEAT INDICIES OF 95 TO 100 SOUTH OF INTERSTATE
80.
THUNDERSTORMS WILL LIKELY FIRE ACROSS FAR NORTHERN ILLINOIS EARLY ON
FRIDAY AS THE FRONT APPROACHES...AND LIKELY INCREASE IN AREAL
COVERAGE BY FRIDAY AFTERNOON. SURFACE BASED STORMS APPEAR
LIKELY...AHEAD OF THE FRONTAL BOUNDARY LATER FRIDAY MORNING AND INTO
THE AFTERNOON...WITH THE PREFRONTAL HIGH THETA-E LOWER LEVEL AIR MASS
EXPECTED TO INDUCE MLCAPES OF 2000-3000 J/KG. ALTHOUGH DEEP LAYER
SHEAR WILL BE SOMEWHAT LACKLUSTER...WITH ONLY AROUND 25 KT OF 0-6 KM
BULK SHEAR...THERE WILL BE A SMALL THREAT FOR MULTI-CELL CLUSTERS
CAPABLE OF PRODUCE STRONG WINDS. HOWEVER...IT APPEAR THE MAIN THREAT
FOR THIS MAY REMAIN SOUTH OF THE CHICAGO AND ROCKFORD AREAS.
THE OTHER THREAT WITH THESE STORMS...AS HAS BEEN THE CASE WITH
STORMS FOR THE LAST FEW WEEKS...IS VERY HEAVY RAINFALL. THE HIGH
THETA E AIR MASS FEATURING PWAT VALUES OF 1.8 TO 2 INCHES WILL LEAD
TO VERY EFFICIENT RAINFALL RATES...AND THIS COUPLED WITH THE FACT
THAT THE STEERING LAYER FLOW LOOKS TO RUN NEARLY PARALLEL TO THE
SURFACE FRONTAL ZONE...TRAINING CELLS ARE A GOOD POSSIBILITY. IT
ALSO APPEARS THAT SHOWERS...POSSIBLY WITH SOME EMBEDDED ELEVATED
THUNDERSTORMS...WILL LIKELY CONTINUE IN THE WAKE OF THE SURFACE
BOUNDARY INTO FRIDAY NIGHT AS AN ANA-LIKE FRONTAL PRECIP EVENT SETS
UP. MID LEVEL FGEN AND THE PROXIMATELY TO THE RIGHT ENTRANCE REGION
OF THE UPPER LEVEL JET ALL POINT TO CONTINUED FORCING TO SUPPORT
PRECIP INTO FRIDAY NIGHT.
GIVEN THE POSSIBILITIES OF A PERIOD OF VERY HEAVY RAINFALL...WITH
POSSIBLE TRAINING OF CELLS AHEAD OF THE FRONT...FOLLOWED BY A LONGER
PERIOD OF MODERATE PRECIP INTO FRIDAY NIGHT...HYDRO ISSUES COULD
BECOME A CONCERN.
THINGS QUIET DOWN AND BECOME MUCH COOLER FOR THE WEEKEND UNDER
NORTHERN FLOW. HIGH TEMPERATURES BY SATURDAY AND SUNDAY LOOK TO BE
IN THE LOW TO MID 70S. OVERNIGHT TEMPERATURES INTO SUNDAY MORNING
LOOKS TO BE QUITE CHILLY AS A SURFACE HIGH BUILDS OVERHEAD. THIS
LOOKS TO SET UP WIDESPREAD LOWER 50 DEGREE TEMPERATURES OUTSIDE OF
CHICAGO...WITH EVEN A FEW UPPER 40 DEGREE READINGS POSSIBLE IN THE
WESTERN SUBURBS.
TEMPERATURES LOOK TO MODERATE A BIT BACK INTO THE UPPER 70S INTO
NEXT WEEK. THE NEXT CHANCE FOR STORMS LOOKS TO ENTER THE PICTURE
AGAIN BY LATE MONDAY NIGHT AND TUESDAY AS ANOTHER DISTURBANCE TAKES
AIM ON THE AREA.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TSRA SLOWLY FADING IN THE LOCAL AREA BUT FIRING ANEW TO THE WEST.
* VARIABLE WINDS AND VSBYS/CIGS NEAR STORMS.
* VARIABLE WINDS IN THE NEAR TERM BECOMING SOUTHERLY LATER TODAY.
LENNING
//DISCUSSION...UPDATED 14Z...
FAIRLY WIDESPREAD RAIN WITH AREAS OF EMBEDDED THUNDERSTORMS WILL
CONTINUE TO MOVE ACROSS THE AREA THIS MORNING. STILL BELIEVE THERE
WILL BE A GRADUAL FADE IN COVERAGE TOWARD LATE MORNING INTO EARLY
AFTERNOON...BUT IN THE NEAR TERM THINGS ARE HANGING TOGETHER
PRETTY WELL. AS PER EARLIER THINKING...THE PREVAILING WIND
DIRECTION WILL WANT TO BE SOUTH-SOUTHWEST OUTSIDE OF THE
STORMS...AND THE DIRECTION SHOULD FALL BACK INTO THAT DURING THE
AFTERNOON.
AFTER A QUIET AFTERNOON AND EVENING THERE WILL AGAIN BE A STRONG
LOW-LEVEL JET CAPABLE OF LOW-LEVEL WIND SHEAR LATE TONIGHT. THIS
ALSO WILL BRING THE POSSIBILITY OF SCATTERED SHRA/TSRA. THE
CHANCES WILL INCREASE THROUGH FRIDAY MORNING AS A COLD FRONT
APPROACHES FROM THE NORTH. THIS FRONT WILL EVENTUALLY SHIFT WINDS
TO THE NORTH TO NORTH-NORTHEAST DURING THE AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE THAT BULK OF TSRA REMAINS AWAY FROM IMMEDIATE
TERMINALS BUT HIGH CONFIDENCE IT REMAINS NEARBY INTO EARLY AFTERNOON.
* LOW CONFIDENCE IN FUTURE TREND OF CELLS BUILDING IN NW IL.
* MEDIUM TO HIGH CONFIDENCE IN SOUTHERLY TREND OF WINDS WITH TEMPO
SOUTHEAST NEAR STORMS.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CHANCE OF SHRA AND SLIGHT CHANCE OF TSRA.
SATURDAY...VFR. NORTHEAST WINDS.
SUNDAY-MONDAY...VFR.
TUESDAY-WEDNESDAY...CHANCE OF TSRA.
MTF
&&
.MARINE...
155 AM CDT
THE WEATHER PATTERN ACROSS THE GREAT LAKES REGION WILL BE A BIT
ACTIVE OVER THE NEXT FEW DAYS...WITH SOME PERIODS OF STRONG WINDS IN
THE 25 TO 30 KT RANG...ALONG WITH A PERIOD OR TWO OF SHOWERS AND
STORMS.
A RATHER POTENT EARLY AUTUMN SEASON SURFACE LOW WILL MOVE FROM THE
EASTERN DAKOTAS EARLY THIS MORNING TO NEAR JAMES BAY BY EARLY FRIDAY
MORNING. THIS SYSTEM WILL CONTINUE TO INDUCE SOME STRONG SOUTHERN
WINDS OVER THE LAKE TODAY AND TONIGHT. IT APPEARS THE STRONGEST
WINDS UP TO AROUND 30 KT WILL OCCUR THIS EVENING ACROSS THE NORTHERN
HALF OF THE LAKE...WITH 20 TO 25 KT SOUTHERLY WINDS OVER THE
SOUTHERN HALF OF THE LAKE. THESE STRONG WINDS WILL RESULT IN SMALL
CRAFT ADVISORY CONDITIONS INTO THIS EVENING.
AS THE LOW SHIFTS OVER THE JAMES BAY FRIDAY MORNING...A TRAILING COLD
FRONT WILL SHIFT DOWN THE LAKE DURING THE DAY FRIDAY. WINDS WILL
SHIFT NORTHERLY INTO 15 TO 25 KT RANGE LATER FRIDAY AND INTO
SATURDAY...BEFORE ABATING LATER SATURDAY AS AN AREA OF SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN LAKES REGION. THESE NORTHERLY
WINDS DOWN THE FETCH OF LAKE MICHIGAN MAY AGAIN RESULT IN SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT AND SATURDAY...WITH WAVES
POSSIBLY IN THE 4 TO 7 FT RANGE.
THE WEATHER CONDITIONS LOOK TO QUIET DOWN FOR A COUPLE DAYS FOR
SUNDAY AND INTO EARLY NEXT WEEK AS SURFACE HIGH PRESSURE DOMINATES
ACROSS THE LAKES REGION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
206 PM EDT THU SEP 4 2014
.SYNOPSIS...
ISSUED AT 1226 PM EDT THU SEP 4 2014
A WARM FRONT WILL MOVE NORTH TODAY AND BRING A SMALL CHANCE FOR
SHOWERS AND THUNDERSTORMS TO NORTHERN INDIANA AND SOUTHWEST LOWER
MICHIGAN THROUGH EARLY AFTERNOON. ELSEWHERE IT WILL BE DRY WITH
PARTLY SUNNY SKIES. HIGHS WILL BE IN THE MID TO UPPER 80S. THERE
WILL BE A SLIGHT CHANCE FOR A THUNDERSTORM TONIGHT...MAINLY AFTER
MIDNIGHT AND NORTH OF HIGHWAY 30. IT WILL REMAIN VERY MUGGY AND
WARM OVERNIGHT WITH LOWS IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EDT THU SEP 4 2014
IMMEDIATE CONCERN IN THE SHORT TERM PERIOD IS HANDLING OF UPSTREAM
CONVECTION THAT HAS FIRED OVERNIGHT. LOW LEVEL JET NOSING INTO
THETA E GRADIENT HAS ALLOWED CONVECTION TO DEVELOP OVER IA AND IT
CONTINUES TO RIDE NOSE OF THIS LLJ AND TRACK EAST. WEAK CONVECTION
HAS TRIED TO FIRE AHEAD OF THIS AREA OVER EASTERN IL AND SOUTHERN
LAKE MICHIGAN BUT IT HAS STRUGGLED SO FAR WITH DRIER AIR STILL IN
PLACE. AS THETA E RIDGE SHIFTS EAST EARLY THIS MORNING EXPECT
CONVECTIVE COMPLEX TO CONTINUE ITS TREK EAST AS WELL. AS DAYTIME
HEATING COMMENCES AND LLJ RELAXES EXPECT THIS CONVECTION TO
DISSIPATE THROUGH THE MORNING HOURS. HIRES MODELS HAVE BEEN TRYING
TO HANDLE THIS ALONG WITH LARGER COMPLEX FURTHER NORTH BUT HAVE
BEEN STRUGGLING WITH EVOLUTION DETAILS. LATEST RUC AND HRRR HAVE
PICKED UP ON IA COMPLEX BUT SEEM UNDERDONE AND HAVE THIS
DISSIPATING BEFORE REACHING THE AREA. EXPECT NEXT FEW RUNS TO BE
MORE AGGRESSIVE BASED ON LATEST RADAR/SATELLITE/LIGHTNING TRENDS.
30 TO 40 KNOT LLJ FEEDING THIS SEEMS TO BE KEEPING IT ON AN
EASTWARD TRACK DESPITE 850-300MB THICKNESS LINES SHOWING A
POSSIBLE MOVEMENT TO THE SOUTHEAST. WILL HAVE TO MONITOR TRENDS
NEXT FEW HOURS CLOSELY BUT FOR NOW HAVE EXPANDED POPS AND
INCREASED SKY COVER THIS MORNING TO COVER MOST OF WESTERN AND
NORTHERN THIRD OF CWA. WILL TAPER POPS OFF BY AFTERNOON WITH SKIES
BECOMING PARTLY CLOUDY TO MOSTLY SUNNY. THIS POSES THE NEXT
PROBLEM WITH HIGH TEMPS FOR TODAY. SOUNDINGS SUGGEST MIXING TO
AROUND 900MB WHICH WILL YIELD HIGHS IN THE MID TO UPPER 80S.
OBVIOUSLY NOW LOOKING AT SLOWER WARMING TRENDS THIS MORNING WITH
SATELLITE SHOWING INCREASED CLOUD DEVELOPMENT. STILL EXPECT A
RAPID WARMUP LATER IN THE DAY ONCE CLOUDS ERODE SO STAYED WITH MID
80S EXCEPT IN FAR SOUTHWEST WHERE UPPER 80S STILL LIKELY.
MODEL SOUNDINGS SHOW DECENT CAPPING INVERSION THIS AFTERNOON DESPITE
MUCAPES CLIMBING TO BETWEEN 1K AND 2K J/KG. DEWPOINTS WILL CREEP
INTO THE UPPER 60S MAKING IT FEEL QUITE HUMID. NOT MUCH FOCUS FOR
CONVECTION TONIGHT BUT MOISTURE RICH AIR WILL BE IN PLACE WITH
ELEVATED INSTABILITY SO IT WILL NOT TAKE MUCH TO SPARK AN ISOLATED
TSRA. WILL KEEP SLIGHT CHANCE POPS ACROSS NORTHERN TWO THIRDS OF
AREA WELL AHEAD OF MAIN COLD FRONT.
&&
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 403 AM EDT THU SEP 4 2014
MAIN FOCUS FRIDAY-FRIDAY NIGHT REMAINS CONVECTIVE CHANCES/COVERAGE
AS TRAILING COLD FRONT FROM POTENT SHORTWAVE TRACKING NE TO JAMES
BAY SAGS SOUTHEAST INTO A MOIST/UNSTABLE AIRMASS. MUCH OF FRIDAY
MORNING-EARLY AFTERNOON SHOULD REMAIN MAINLY DRY IN CAPPED WARM
SECTOR (850 MB TEMPS 21C)...ALTHOUGH CANNOT COMPLETELY RULE OUT
CONVECTIVE REMNANTS/OUTFLOW SURVIVING INTO NORTHERN/WESTERN ZONES IN
LOW LEVEL THETA-E ADVECTION REGIME. EXPECTED STRONG DIURNAL HEATING
AND POOLED 70F DEWPOINTS NEAR FRONT...CONCURRENT WITH OVERSPREAD OF
WEAK 20-30M 5H HEIGHT FALLS...SHOULD BE SUFFICIENT TO BREAK CAP/FIRE
CONVECTION ALONG THE SAGGING FRONTAL ZONE BY MID-LATE AFTERNOON.
COVERAGE REMAINS QUESTIONABLE HOWEVER WITH BETTER MID LEVEL HEIGHT
FALLS/FORCING INITIALLY CONFINED NORTH. THIS REMAINS THE PRIMARY
REASON FOR HOLDING SHY OF LIKELY POPS AT THIS FCST RANGE. POST
FRONTAL LAG OF STRONGER MID LEVEL FLOW/DEEP SHEAR AND WHAT SHOULD BE
A VERY UNSTABLE ENVIRONMENT (MLCAPE 2500 J/KG PLUS) HINTS AT A LOW
END SEVERE THREAT (ISOLATED) WITH SHORT-LIVED UPDRAFTS CAPABLE OF
PRODUCING STRONG OUTFLOWS/DOWNBURSTS. FAIR AMOUNT OF CAPE IN THE
M10-M30 LAYER ALSO SUGGESTIVE OF A LOW END HAIL THREAT AS WELL.
OVERSPREAD OF BETTER HEIGHT FALLS/RIGHT ENTRANCE UPPER JET SUPPORT
WILL TIGHTEN/DEEPEN THE FRONTAL ZONE AS IT DROPS THROUGH
SOUTHERN/EASTERN ZONES FRIDAY NIGHT...WITH AMPLE MOISTURE AND
POTENTIAL FOR LOWER AMPLITUDE SHORTWAVE ENERGY TO PROPAGATE THROUGH
IN SW FLOW PROBABLY ENOUGH TO HELP GENERATE ADDITIONAL RAIN/THUNDER
ALONG FRONTAL SLOPE. WITH THAT SAID...ONCE AGAIN HELD SHY OF LIKELY
POPS GIVEN NORMAL UNCERTAINTIES WITH CONVECTION AND RECENT MAINLY
DRY FRONTAL PASSAGES IN SIMILAR SETUPS.
A FEW SHOWERS/LOW CLOUDS MAY LINGER INTO SATURDAY MORNING ACROSS
SOUTHERN/EASTERN ZONES...WITH THE REST OF THE WEEKEND INTO EARLY
NEXT WEEK MUCH COOLER/DRIER AS BROAD HIGH PRESSURE BUILDS IN WAKE OF
FRONT/SHORTWAVE TROUGH. RETURN FLOW TIMED WITH THE NEXT ROUND OF
HEIGHT FALLS ON THE BACKSIDE OF THIS AREA OF HIGH PRESSURE BRINGS
SHOWER/STORM CHANCES BACK INTO THE FORECAST BY THE MIDDLE OF NEXT
WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 152 PM EDT THU SEP 4 2014
THERE WAS A VERY TIGHT SURFACE THETA E GRADIENT OVER NRN IL...BUT
WELL TO THE SOUTHWEST OF CHICAGO. SPC MESOANALYSIS GRAPHICS AND EARLY
MORNING SOUNDINGS INDICATE INCREASINGLY STABLE CONDITIONS FURTHER
EAST INTO INDIANA...WITH ONGOING CONVECTIVE ACTIVITY HAVING A HARD
TIME SUSTAINING ITSELF ACROSS NRN INDIANA. GIVEN THIS ENVIRONMENT...
THE LATEST RADAR TRENDS...AND SOME HIGH RESOLUTION NCEP MODELS
THAT ARE FINALLY STARTING TO HANDLE THIS SCENARIO...KEPT THE TAFS
DRY. EXPECT THE FRONT WILL DROP SOUTHEAST INTO THE AREA FRIDAY
AFTERNOON...WITH STORMS DEVELOPING JUST AFTER THE END OF THE TAF
PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...CEO
SHORT TERM...LASHLEY
LONG TERM...STEINWEDEL
AVIATION...SKIPPER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1227 PM EDT THU SEP 4 2014
.SYNOPSIS...
ISSUED AT 1226 PM EDT THU SEP 4 2014
A WARM FRONT WILL MOVE NORTH TODAY AND BRING A SMALL CHANCE FOR
SHOWERS AND THUNDERSTORMS TO NORTHERN INDIANA AND SOUTHWEST LOWER
MICHIGAN THROUGH EARLY AFTERNOON. ELSEWHERE IT WILL BE DRY WITH
PARTLY SUNNY SKIES. HIGHS WILL BE IN THE MID TO UPPER 80S. THERE
WILL BE A SLIGHT CHANCE FOR A THUNDERSTORM TONIGHT...MAINLY AFTER
MIDNIGHT AND NORTH OF HIGHWAY 30. IT WILL REMAIN VERY MUGGY AND
WARM OVERNIGHT WITH LOWS IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM EDT THU SEP 4 2014
IMMEDIATE CONCERN IN THE SHORT TERM PERIOD IS HANDLING OF UPSTREAM
CONVECTION THAT HAS FIRED OVERNIGHT. LOW LEVEL JET NOSING INTO
THETA E GRADIENT HAS ALLOWED CONVECTION TO DEVELOP OVER IA AND IT
CONTINUES TO RIDE NOSE OF THIS LLJ AND TRACK EAST. WEAK CONVECTION
HAS TRIED TO FIRE AHEAD OF THIS AREA OVER EASTERN IL AND SOUTHERN
LAKE MICHIGAN BUT IT HAS STRUGGLED SO FAR WITH DRIER AIR STILL IN
PLACE. AS THETA E RIDGE SHIFTS EAST EARLY THIS MORNING EXPECT
CONVECTIVE COMPLEX TO CONTINUE ITS TREK EAST AS WELL. AS DAYTIME
HEATING COMMENCES AND LLJ RELAXES EXPECT THIS CONVECTION TO
DISSIPATE THROUGH THE MORNING HOURS. HIRES MODELS HAVE BEEN TRYING
TO HANDLE THIS ALONG WITH LARGER COMPLEX FURTHER NORTH BUT HAVE
BEEN STRUGGLING WITH EVOLUTION DETAILS. LATEST RUC AND HRRR HAVE
PICKED UP ON IA COMPLEX BUT SEEM UNDERDONE AND HAVE THIS
DISSIPATING BEFORE REACHING THE AREA. EXPECT NEXT FEW RUNS TO BE
MORE AGGRESSIVE BASED ON LATEST RADAR/SATELLITE/LIGHTNING TRENDS.
30 TO 40 KNOT LLJ FEEDING THIS SEEMS TO BE KEEPING IT ON AN
EASTWARD TRACK DESPITE 850-300MB THICKNESS LINES SHOWING A
POSSIBLE MOVEMENT TO THE SOUTHEAST. WILL HAVE TO MONITOR TRENDS
NEXT FEW HOURS CLOSELY BUT FOR NOW HAVE EXPANDED POPS AND
INCREASED SKY COVER THIS MORNING TO COVER MOST OF WESTERN AND
NORTHERN THIRD OF CWA. WILL TAPER POPS OFF BY AFTERNOON WITH SKIES
BECOMING PARTLY CLOUDY TO MOSTLY SUNNY. THIS POSES THE NEXT
PROBLEM WITH HIGH TEMPS FOR TODAY. SOUNDINGS SUGGEST MIXING TO
AROUND 900MB WHICH WILL YIELD HIGHS IN THE MID TO UPPER 80S.
OBVIOUSLY NOW LOOKING AT SLOWER WARMING TRENDS THIS MORNING WITH
SATELLITE SHOWING INCREASED CLOUD DEVELOPMENT. STILL EXPECT A
RAPID WARMUP LATER IN THE DAY ONCE CLOUDS ERODE SO STAYED WITH MID
80S EXCEPT IN FAR SOUTHWEST WHERE UPPER 80S STILL LIKELY.
MODEL SOUNDINGS SHOW DECENT CAPPING INVERSION THIS AFTERNOON DESPITE
MUCAPES CLIMBING TO BETWEEN 1K AND 2K J/KG. DEWPOINTS WILL CREEP
INTO THE UPPER 60S MAKING IT FEEL QUITE HUMID. NOT MUCH FOCUS FOR
CONVECTION TONIGHT BUT MOISTURE RICH AIR WILL BE IN PLACE WITH
ELEVATED INSTABILITY SO IT WILL NOT TAKE MUCH TO SPARK AN ISOLATED
TSRA. WILL KEEP SLIGHT CHANCE POPS ACROSS NORTHERN TWO THIRDS OF
AREA WELL AHEAD OF MAIN COLD FRONT.
&&
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 403 AM EDT THU SEP 4 2014
MAIN FOCUS FRIDAY-FRIDAY NIGHT REMAINS CONVECTIVE CHANCES/COVERAGE
AS TRAILING COLD FRONT FROM POTENT SHORTWAVE TRACKING NE TO JAMES
BAY SAGS SOUTHEAST INTO A MOIST/UNSTABLE AIRMASS. MUCH OF FRIDAY
MORNING-EARLY AFTERNOON SHOULD REMAIN MAINLY DRY IN CAPPED WARM
SECTOR (850 MB TEMPS 21C)...ALTHOUGH CANNOT COMPLETELY RULE OUT
CONVECTIVE REMNANTS/OUTFLOW SURVIVING INTO NORTHERN/WESTERN ZONES IN
LOW LEVEL THETA-E ADVECTION REGIME. EXPECTED STRONG DIURNAL HEATING
AND POOLED 70F DEWPOINTS NEAR FRONT...CONCURRENT WITH OVERSPREAD OF
WEAK 20-30M 5H HEIGHT FALLS...SHOULD BE SUFFICIENT TO BREAK CAP/FIRE
CONVECTION ALONG THE SAGGING FRONTAL ZONE BY MID-LATE AFTERNOON.
COVERAGE REMAINS QUESTIONABLE HOWEVER WITH BETTER MID LEVEL HEIGHT
FALLS/FORCING INITIALLY CONFINED NORTH. THIS REMAINS THE PRIMARY
REASON FOR HOLDING SHY OF LIKELY POPS AT THIS FCST RANGE. POST
FRONTAL LAG OF STRONGER MID LEVEL FLOW/DEEP SHEAR AND WHAT SHOULD BE
A VERY UNSTABLE ENVIRONMENT (MLCAPE 2500 J/KG PLUS) HINTS AT A LOW
END SEVERE THREAT (ISOLATED) WITH SHORT-LIVED UPDRAFTS CAPABLE OF
PRODUCING STRONG OUTFLOWS/DOWNBURSTS. FAIR AMOUNT OF CAPE IN THE
M10-M30 LAYER ALSO SUGGESTIVE OF A LOW END HAIL THREAT AS WELL.
OVERSPREAD OF BETTER HEIGHT FALLS/RIGHT ENTRANCE UPPER JET SUPPORT
WILL TIGHTEN/DEEPEN THE FRONTAL ZONE AS IT DROPS THROUGH
SOUTHERN/EASTERN ZONES FRIDAY NIGHT...WITH AMPLE MOISTURE AND
POTENTIAL FOR LOWER AMPLITUDE SHORTWAVE ENERGY TO PROPAGATE THROUGH
IN SW FLOW PROBABLY ENOUGH TO HELP GENERATE ADDITIONAL RAIN/THUNDER
ALONG FRONTAL SLOPE. WITH THAT SAID...ONCE AGAIN HELD SHY OF LIKELY
POPS GIVEN NORMAL UNCERTAINTIES WITH CONVECTION AND RECENT MAINLY
DRY FRONTAL PASSAGES IN SIMILAR SETUPS.
A FEW SHOWERS/LOW CLOUDS MAY LINGER INTO SATURDAY MORNING ACROSS
SOUTHERN/EASTERN ZONES...WITH THE REST OF THE WEEKEND INTO EARLY
NEXT WEEK MUCH COOLER/DRIER AS BROAD HIGH PRESSURE BUILDS IN WAKE OF
FRONT/SHORTWAVE TROUGH. RETURN FLOW TIMED WITH THE NEXT ROUND OF
HEIGHT FALLS ON THE BACKSIDE OF THIS AREA OF HIGH PRESSURE BRINGS
SHOWER/STORM CHANCES BACK INTO THE FORECAST BY THE MIDDLE OF NEXT
WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 740 AM EDT THU SEP 4 2014
TSRA COMPLEX EXTENDING FROM WRN LWR MI SWWD INTO WEST CENTRAL IL
MAKING SLOW EASTWARD PROGRESS EARLY THIS MORNING. EXPECT
BACKING/WKNG LLJ THIS MORNING WILL RESULT IN A MORE NEWD TREND
WITH MOVEMENT OF MCS AS WELL AS A DIMINISHING TREND. WOULDN`T
TOTALLY RULE OUT A SHRA/TSRA REACHING KSBN THROUGH 14-15Z BUT
THREAT REMAINS LOW ENOUGH NOT TO INCLUDE TEMPO GROUP. OTRWS VFR
CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD AT BOTH TERMINALS.
AGAIN TONIGHT THERE IS SOME POTENTIAL FOR TSRA AS LOW LEVEL
THETA-E ADVECTION/CONVERGENCE OVERSPREAD THE AREA BUT ATTM
CONFIDENCE TOO LOW TO INCLUDE IN TAFS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...CEO
SHORT TERM...LASHLEY
LONG TERM...STEINWEDEL
AVIATION...JT
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
1231 PM CDT THU SEP 4 2014
.SYNOPSIS...
ISSUED AT 304 AM CDT THU SEP 4 2014
COLD FRONT FROM EASTERN SD INTO CO WILL MOVE SOUTHEAST ACROSS THE
STATE BY FRIDAY MORNING. A WAVE WILL MOVE NORTHEAST ALONG THE
FRONT ON FRIDAY...PASSING SOUTH OF IA DURING THE DAY. HIGH
PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND. NEXT FRONTAL
SYSTEM SLATED TO MOVE THROUGH THE AREA ABOUT TUESDAY.
&&
.SHORT TERM /TODAY/...
ISSUED AT 304 AM CDT THU SEP 4 2014
MAIN FORECAST CONCERN WAS ANOTHER HOT AND HUMID DAY AND
WITH POTENTIAL FOR CONVECTION LATE THIS AFTERNOON. LEANED TOWARD THE
SLIGHTLY WARMER ECMWF/GFS FOR HIGHS TODAY AS THERE SHOULD BE SOME
DECENT MIXING TO AROUND 900MB AND WAA THROUGHOUT THE DAY. THE WAA
HAS KEPT TEMPS UP OVERNIGHT IN THE MID TO UPPER 70S. A SHARP COLD
FRONT IS SLATED TO PUSH INTO NORTHWEST LATE THIS AFTERNOON INTO THE
EVENING AND CAP LOOKS TO HOLD THROUGH MUCH OF THE DAY. THE HIRES
MODELS (NMM/ARW) BREAK OUT SOME ISOLATED STORMS BY 19-20Z TODAY.
HOWEVER...THE 04.00Z HOPWRF/04.05Z HRRR KEYING IN ON A VERY WEAK
SHORTWAVE OVER SOUTHERN NEBRASKA AND HAS STORMS DEVELOPING BY AROUND
16-17Z. HOWEVER...BELIEVE THE STRONG CAP IN PLACE WILL HOLD UNTIL
THE COLD FRONT LATER THIS AFTERNOON ENTERS THE STATE. ONE THING TO
NOTE...IF WEAK ISOLATED CONVECTION THAT THE HOPWRF/HRRR DOES
DEVELOP...WILL HINDER MAX TEMPS A LITTLE TODAY OVER THE SOUTH. AT
ANY RATE...HAVE POPS INCREASING PAST 20Z OVER THE WEST TO NORTHWEST
AS THE COLD FRONT BEGINS TO SAG SOUTHEAST INTO THE STATE.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 304 AM CDT THU SEP 4 2014
THUNDERSTORMS ARE LIKELY TO DEVELOP ALONG AND JUST BEHIND THE COLD
FRONT DAY AS IT SLIDES SOUTHEAST AIRMASS IS QUITE CAPPED
INITIALLY...BUT COLD AIR ALOFT WILL ALLOW THE CAP TO BREAK AND
EXPECT A LINE OF THUNDERSTORMS TO DEVELOP AND MOVE TROUGH THE
STATE. RAIN WILL CONTINUE OVER THE SOUTH AND EAST ON FRIDAY AS A
S/WV RESULTS IN A WAVE LIFTING NORTHEAST ALONG THE FRONT FRIDAY.
HIGH PRESSURE WILL PUSH IN AND DOMINATE THE WEATHER OVER THE
WEEKEND WITH COOLER AND DRIER AIR IN PLACE. THE NEXT FRONTAL
SYSTEM WILL BE WEAKER...BUT WILL BRING A CHANCE FOR RAIN IN THE
MONDAY TUESDAY TIMEFRAME. DO NOT EXPECT TO SEE THE WARMING WITH
THE NEXT SYSTEM THAT IS OCCURRING BEFORE THE CURRENT COLD FRONT.
FURTHER AHEAD...A STRONGER FRONT WILL BRING A CHANCE FOR RAIN
ABOUT THURSDAY. MUCH COLDER AIR WILL SETTLE IN BEHIND THE FRONT
LATER NEXT WEEK WITH THE A COOL PUSH OF FALL AIR OVER THE UPPER
MIDWEST. THE MODELS HAVE BECOME MORE CONSISTENT WITH THIS BOTH IN
MODEL TO MODEL AND RUN TO RUN CONTINUITY.
&&
.AVIATION...04/18Z
ISSUED AT 1231 PM CDT THU SEP 4 2014
A COLD FRONT IS APPROACHING FROM THE NORTHWEST AND WILL SWEEP
ACROSS THE AREA THIS EVENING AND TONIGHT...ARRIVING AT OTM JUST
BEFORE SUNSET FRIDAY. THE FRONT WILL BE ACCOMPANIED BY SOME
THUNDERSTORMS AS IT MOVES THROUGH BUT AMOUNT OF COVERAGE IS VERY
UNCERTAIN AT THIS TIME...THUS HAVE MAINTAINED JUST VCTS IN THE 18Z
TAFS. LOWER CIGS WILL ALSO MOVE IN WITH/BEHIND THE FRONT BUT ARE
MOSTLY EXPECTED TO BE VFR OUTSIDE OF STORMS. WINDS WILL SWITCH TO
NNW BY FRIDAY MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS SEP 14
SHORT TERM...PODRAZIK
LONG TERM...MS SEP 14
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
200 PM MDT THU SEP 4 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
WV LOOP AND RAP ANALYSIS SHOWS EXPANSIVE UPPER RIDGE JUST TO OUR
SOUTHEAST WITH PLUME OF MID LEVEL MOISTURE MOVING NORTHEASTWARD
ACROSS THE SOUTHWEST CONUS IN TO THE CENTRAL ROCKIES. CIRRUS WAS
OVERSPREADING THE CENTRAL HIGH PLAINS. AHEAD OF AN EASTWARD MOVING
POSITIVELY TILTED SHORTWAVE TROUGH OVER THE NORTHERN PLAINS. A COLD
FRONT FORCED BY THE AFOREMENTIONED TROUGH HAS MADE IT THROUGH THE
FORECAST AREA AND TEMPERATURES WERE NOTICEABLY COOLER THAN 24 HOURS
PRIOR. MID TO UPPER 70S WERE COMMON IN THE NORTHWEST HALF OF THE
FORECAST AREA WHICH SAW THE EARLIEST FRONTAL PASSAGE. WINDS
IMMEDIATELY BEHIND THE FRONT GUSTED FROM THE NORTH AT 30-35 MPH BUT
HAVE SUBSIDED SOME THIS AFTERNOON. STILL...DIURNAL HEATING AND
MIXING IS CONTRIBUTING TO GUSTS APPROACHING 30 MPH. WINDS WILL
CONTINUE TO DECREASE THROUGH THE AFTERNOON...ESPECIALLY WHEN MIXING
LESSENS THIS EVENING.
CHALLENGES FOR THE SHORT TERM INCLUDE PRECIPITATION CHANCES THIS
EVENING THROUGH TOMORROW AND THE POSSIBILITY OF MARGINALLY SEVERE
HAIL WITH A FEW OF THE THUNDERSTORMS THIS EVENING. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE GIVEN PWAT VALUES APPROACHING 2 STANDARD
DEVIATIONS ABOVE CLIMO FOR EARLY SEPTEMBER. EVENT QPF TOTALS WILL BE
AROUND ONE INCH FOR THE FAR SOUTH PORTION OF THE FORECAST AREA
TAPERING TO A TENTH OF AN INCH OR LESS IN THE FAR NORTHWEST PORTION
OF THE AREA. STILL SOME UNCERTAINTY ON QPF AMOUNTS AND EXACT
PLACEMENT OF HEAVIER TOTALS ALTHOUGH SHORT RANGE GUIDANCE HAS COME
INTO BETTER AGREEMENT WITH TIMING.
SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ACROSS THE SOUTHERN PORTION
OF THE AREA NEAR AND JUST NORTH OF THE FRONT LATER THIS EVENING AND
THEN CONTINUE TO DEVELOP NORTHWARD AS ISENTROPIC LIFT INCREASES ON
THE COOL SIDE OF THIS BOUNDARY. THE STRONGEST CONVECTION SHOULD
OCCUR THROUGH THE EVENING AND EARLY TONIGHT BEFORE INSTABILITY
WANES. ISOLATED MARGINALLY SEVERE HAIL SEEMS POSSIBLE GIVEN 30-40
KNOT DEEP LAYER SHEAR AND AROUND 1000 J/KG MUCAPE. THIS THREAT
SHOULD BE CONFINED TO THE SOUTHERN PORTION OF THE AREA. LATER IN THE
NIGHT SHOWERS AND THUNDERSTORMS SHOULD BECOME FAIRLY WIDESPREAD AS
ISENTROPIC LIFT MAXIMIZES OVER THE AREA...PARTICULARLY IN THE
SOUTHEASTERN PORTION WHERE HIGHER QPF AMOUNTS ARE. MODELS HAVE
TRENDED SLOWER SO ENDING TIME OF THE PRECIPITATION EVENT IS A LITTLE
UNCERTAIN BUT BY MID/LATE MORNING THE HEAVIEST PRECIPITATION WILL
HAVE SHIFTED EAST OF THE AREA. SOME SHOWERS WILL LINGER IN THE
SOUTHEAST THROUGH THE AFTERNOON BEFORE THE UPPER LEVEL TROUGH AXIS
MOVES THROUGH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
FRIDAY NIGHT THERE MAYBE SOME LINGERING RAINFALL OVER THE FAR
EAST/SOUTHEAST PART OF THE AREA AHEAD OF THE DEPARTING 500MB SHORT
WAVE TROUGH. THE RAINFALL SHOULD BE EAST OF THE AREA BY MID TO LATE
EVENING. DUE TO THE LOWEST 50MB OR SO OF THE SOUNDINGS REMAINING
SATURATED THOUGHT ABOUT MENTIONING FOG IN THE FORECAST LATE FRIDAY
NIGHT. HOWEVER LOOKS LIKE THE CLOUD COVER WILL REMAIN OVER THE
AREA. IF SKIES CLEAR OVERNIGHT FOG WILL BE MUCH MORE LIKELY TO
DEVELOP. A SURFACE HIGH MOVES THROUGH THE AREA SO WINDS WILL BECOME
LIGHT AND VARIABLE. WITH A COOL AIR MASS IN PLACE LOWS WILL BE WELL
BELOW NORMAL.
SATURDAY AND SATURDAY NIGHT VERY WEAK RIPPLES IN THE UPPER LEVEL
FLOW MOVE OVER THE AREA. SOUNDINGS SHOW A CAPPED UNSATURATED
ENVIRONMENT SO THESE TWO PERIODS WILL BE DRY. DURING THE DAY THE
SURFACE HIGH MOVES EAST WHICH WILL ALLOW WARMER AIR FROM THE SOUTH
TO MOVE INTO THE AREA. SATURDAY NIGHT WILL BE A FEW DEGREES WARMER
THAN FRIDAY NIGHT.
SUNDAY THROUGH THURSDAY NUMEROUS WEAK UPPER LEVEL DISTURBANCES WILL
MOVE ACROSS THE AREA. LATEST RUN OF MODELS DISAGREES WITH THE
PROGRESSION AND LOCATION OF THE STRONGER UPPER LEVEL SHORT WAVE
TROUGH THAT WILL MOVE THROUGH MONDAY THROUGH TUESDAY...THUS LOWERING
CONFIDENCE OF WHEN/WHERE RAINFALL WILL DEVELOP. TUESDAY THROUGH
WEDNESDAY A STRONGER MORE WELL DEFINED UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE THROUGH THE AREA...SO WILL HAVE HIGHER RAINFALL CHANCES AS
A RESULT. A STRONG COLD FRONT MOVES THROUGH WEDNESDAY EVENING BUT
MOISTURE AND UPPER LEVEL FORCING DO NOT LOOK VERY FAVORABLE FOR
STORM DEVELOPMENT AS THE FRONT MOVES THROUGH.
TEMPERATURES FOR THE PERIOD WILL GRADUALLY WARM THROUGH TUESDAY AS
THE COOLER AIR MASS GRADUALLY MOVES EAST. MID WEEK A STRONG COLD
FRONT MOVES INTO THE AREA WEDNESDAY NIGHT WITH THE COOLER AIR
CONTINUING TO MOVE INTO THE AREA THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1141 AM MDT THU SEP 4 2014
WINDS WILL GRADUALLY SUBSIDE THIS AFTERNOON AS THE COLD FRONT
CONTINUES TO MOVE SOUTHWARD AWAY FROM THE AREA. FOR THE NEXT FEW
HOURS GUSTS IN THE 25-30 KNOT RANGE ARE EXPECTED AT BOTH KGLD AND
KMCK. CLOUDS WILL LOWER AND THICKEN THROUGHOUT THE REST OF THE DAY
BUT VFR CONDITIONS SHOULD PREVAIL UNTIL AFTER 06Z. SHOWERS AND
THUNDERSTORMS WILL INCREASE IN COVERAGE THIS EVENING WITH A GOOD
CHANCE OF AT LEAST INTERMITTENT IMPACT TO BOTH TERMINALS OVER
NIGHT AND EARLY TOMORROW. MVFR IS LIKELY FOR A PERIOD LATE TONIGHT
DUE MAINLY TO LOW CEILINGS AND CONDITIONS COULD APPROACH IFR AT
LEAST BRIEFLY TOMORROW MORNING. THUNDER WILL BE MOST LIKELY AT
KGLD LATE THIS EVENING AND EARLY TONIGHT...BUT AT LEAST A LOW
CHANCE EXISTS AT KMCK ALSO LATER TONIGHT. THE MORE WIDESPREAD RAIN
WILL MOVE EAST OF BOTH TERMINALS BY MID MORNING THOUGH MVFR
CEILINGS MAY LINGER THROUGH THE END OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...BRB
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
149 PM EDT THU SEP 4 2014
.UPDATE...
ISSUED AT 1255 PM EDT THU SEP 4 2014
HOURLY GRIDS WERE UPDATED BASED ON RECENT OBSERVATIONS AND MODEL
TRENDS. THE RECENT HRRR RUNS HAVE A DECENT HANDLE ON THE SCENARIO AT
THIS TIME. POPS WERE RAISED ACROSS MUCH OF THE CWA MOSTLY INTO THE
SCATTERED CATEGORY...WITH ISOLATED POPS INTRODUCED ACROSS THE
BLUEGRASS COUNTIES. THE MOISTURE RETURN NORTH HAS BROUGHT A PLUME OF
DEEP MOISTURE WITH PW OF 1.8 INCHES OR MORE INTO THE KY/TN/VA TRI
STATE AREA...THOUGH PW IS GENERALLY 1.5 INCHES OR MORE ACROSS MOST OF
THE CWA. ANY THUNDERSTORMS THIS AFTERNOON WILL BE CAPABLE OF LOCALLY
HEAVY DOWNPOURS...AND IF THEY PERSIST SOME LOCALLY HEAVY RAINFALL. SO
FAR THE HEAVIEST RAINFALL HAS FALLEN FROM MORE PERSISTENT SHOWERS AND
THUNDERSTORMS IN PARTS OF THE CUMBERLAND VALLEY REGION.
SHOWERS AND THUNDERSTORMS SHOULD PEAK IN COVERAGE LATER THIS
AFTERNOON AND EARLY THIS EVENING AND THEN WANE TOWARD SUNSET...AS
THE UPPER LEVEL DISTURBANCE MOVING ACROSS THE OH VALLEY REGION
BEGINS TO DEPART TO THE NORTH AND EAST AND THE DEEPEST MOISTURE IS
ALSO SHUNTED TO THE EAST AND SOUTHEAST OF THE REGION.
UPDATE ISSUED AT 1019 AM EDT THU SEP 4 2014
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
TRENDS. A FRESH ZFP WAS ALSO ISSUED TO GET RID OF MORNING FOG WORDING
AS SATELLITE IMAGERY AND OBSERVATIONS INDICATE THAT VALLEY FOG
CONTINUES TO LIFT. THE FOG HAS LIFTED INTO A STRATUS DECK IN SOME
RIVER VALLEY LOCATIONS AND NEAR A FEW AREA LAKES...THIS ALSO IS
GRADUALLY ERODING AWAY.
RATHER LIGHT SOUTHWESTERLY FLOW WILL BRING INCREASING MOISTURE TO THE
AREA BELOW 500 MB. THERE IS ALSO A SHORTWAVE TROUGH OR WEAKNESS
BETWEEN RIDGING CENTERED NEAR BERMUDA AND ACROSS THE SOUTHEASTERN
STATES AND ANOTHER UPPER LEVEL RIDGE CENTERED IN THE MS VALLEY
REGION. THIS SHORTWAVE WILL WORK ACROSS THE REGION TODAY AND INTO
THIS EVENING. THE COMBINATION OF CURRENT RATHER STRONG SFC HEATING
AND THE INCREASING MOISTURE ALONG WITH THE WEAK SHORTWAVE TO MOVE
ACROSS THE AREA SHOULD BRING ISOLATED TO SCATTERED CONVECTION TO
PARTS OF THE REGION FROM MIDDAY INTO THE EVENING HOURS. THE CHANCES
FOR CONVECTION STILL APPEAR TO BE HIGHEST NEAR THE VA BORDER WITH
DEEPER MOISTURE THERE.
UPDATE ISSUED AT 758 AM EDT THU SEP 4 2014
HAVE UPDATED THE FORECAST GRIDS BASED ON LATEST OBS...BUT WITH NO
SUBSTANTIAL EFFECT ON THE OVERALL FORECAST.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 352 AM EDT THU SEP 4 2014
LIGHT WINDS...CLEAR TO PARTLY CLOUDY SKIES...AND A MOIST AIR MASS
HAVE ALLOWED TYPICAL SEASONAL VALLEY FOG TO DEVELOP EARLY THIS
MORNING. IT WILL DISSIPATE DURING THE MORNING...BUT GO THROUGH ITS
CYCLE AGAIN TONIGHT/FRIDAY. SOMEWHAT DRIER AIR MADE IT INTO THE FAR
NORTHERN PART OF THE FORECAST AREA ON WEDNESDAY AFTERNOON...BUT WILL
NOT GET ANY FURTHER SOUTH. LOW LEVEL FLOW WILL CARRY MOISTURE NORTH
AND NORTHEAST...ENSURING ALL AREAS ARE UNCOMFORTABLY HUMID TODAY
THROUGH FRIDAY. THE HUMIDITY MAY FUEL DEVELOPMENT OF A FEW SHOWERS
AND THUNDERSTORMS EACH AFTERNOON. THE GREATEST PROBABILITY WILL BE
NEAR THE VA BORDER...WHERE MOISTURE WILL BE THE DEEPEST. FURTHER
NW...FORECAST SOUNDINGS SHOW THE MOISTURE BEING MORE SHALLOW...WITH
DRY AIR ALOFT BEING LESS SUPPORTIVE OF SUSTAINED CONVECTION IN THE
ABSENCE OF DYNAMIC SUPPORT. IN ADDITION...WARMER MID LEVEL TEMPS IN
OUR NW COUNTIES WILL ALSO MAKE IT MORE DIFFICULT TO GET DEEP
CONVECTION THIS AFTERNOON. WINDS ALOFT WILL BE WEAK THROUGH THE
PERIOD...AND LITTLE ORGANIZATION OF CONVECTION IS EXPECTED...HELPING
TO LIMIT COVERAGE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 AM EDT THU SEP 4 2014
BIG WEATHER CHANGE STILL ANTICIPATED THIS COMING WEEKEND AS MODELS
REMAIN IN FAIRLY GOOD AGREEMENT. THE ONLY CHANGE WAS THAT MODELS
HAVE SLOWED DOWN THE COLD FRONT A TAD...WHICH COULD NOW IMPACT THE
FORECAST FOR SUNDAY. STARTING OFF THE PERIOD...DIURNALLY DRIVEN
CONVECTION WILL DIE OFF EARLY FRIDAY EVENING...LEAVING DRY
CONDITIONS FOR MUCH OF THE AREA THROUGH THE OVERNIGHT HOURS. THE
EXPECTED COLD FRONT WILL MARCH INTO NORTHERN KENTUCKY BY MIDDAY
SATURDAY AND SWING SOUTH THROUGH THE AFTERNOON AND EVENING HOURS.
THIS WILL YIELD WIDESPREAD SHOWERS AND THUNDERSTORMS. HOWEVER...WITH
THE MODELS SLOWING DOWN THE FRONT...LOOKS LIKE PRECIPITATION COULD
LINGER INTO SATURDAY NIGHT AND EVEN INTO SUNDAY BEFORE ENDING LATE
IN THE DAY ON SUNDAY. INSTABILITY SHOULD STILL DROP OFF OVERNIGHT
SATURDAY NIGHT...SO THUNDER CHANCES WILL DIMINISH...BUT RAIN SHOWERS
MAY PERSIST. THIS COULD SET UP A BIT WETTER AND CERTAINLY CLOUDIER
SUNDAY FOR THOSE ACROSS THE SOUTH AND SOUTHEAST. REGARDLESS...HIGHS
WILL ONLY REACH THE LOW TO MID 70S WITH THE ADDED CLOUD COVER AND
COLD ADVECTION BEHIND THE FRONT. SUNDAY NIGHT WILL BE MUCH COOLER AS
TEMPERATURES INTO THE 50S ARE EXPECTED.
WHILE HIGH PRESSURE WILL BEGIN TO BUILD OVER THE AREA EARLY NEXT
WEEK...SOME MOISTURE WILL REMAIN OVER EASTERN KENTUCKY...SUPPORTING
AN ISOLATED SHOWER OR TWO. HOWEVER...INSTABILITY IS WEAK...AND FLOW
ON MONDAY MAY BE FROM A SOUTHEAST DIRECTION...LEADING TO
DOWNSLOPING...WHICH COULD SQUASH ANYTHING FROM FORMING. FOR
NOW...WILL GO WITH A 20 POP TO COVER THE SMALL CHANCE. MODELS START
DIVERGING QUITE A BIT AND HAVE STARTING TO FLIP FLOP ON VARIOUS
SOLUTIONS AS WE HEAD TOWARDS TUESDAY. AT THIS TIME...OPTING TO KEEP
EACH DAYTIME PERIOD WITH LOW POPS WITH LOWER COVERAGE AT NIGHT UNTIL
WE SEE BETTER AGREEMENT WITH OUR NEXT WEATHER MAKER.
THUS...CONFIDENCE IN THE FORECAST BEYOND MONDAY IS VERY LOW. IT DOES
LOOK LIKE TEMPERATURES SHOULD REBOUND A BIT AS WE HEAD THROUGH NEXT
WEEK...BUT THE EXTREME WARMTH SHOULD STAY AWAY FOR A LITTLE WHILE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 140 PM EDT THU SEP 4 2014
SCATTERED TO NUMEROUS SHOWERS AND SOME THUNDERSTORMS WITH REDUCTIONS
TO MVFR WILL WORK ACROSS THE TAF SITES DURING THE FIRST 6 HOURS OF
THE PERIOD. THE MOST LIKELY STATIONS TO EXPERIENCE A THUNDERSTORM
THROUGH 19Z ARE LOZ AND SME. HOWEVER...VCTS WAS CARRIED AT JKL AND
SJS FOR THE FIRST 4 HOURS OF THE PERIOD. MOISTURE WILL DECREASE AS
THE ASSOCIATED UPPER LEVEL DISTURBANCE BEGINS TO DEPART AND WITH LOSS
OF DAYTIME HEATING...CONVECTION SHOULD WANE BY SUNSET. FOG WILL DEVELOP
IN VALLEYS...GENERALLY AFTER 5Z AND PROBABLY AFFECT ALL THE TAF SITES
THROUGH 14Z. WITH RAIN HAVING FALLEN AND THE LOW LEVELS REMAINING
MOIST...THIS FOG MAY REDUCE VIS BELOW AIRPORT MINS AT ALL SITES FOR
A TIME TOWARD DAWN. THE FOG SHOULD LIFT AND DISSIPATE BY 14Z...WITH
VFR FROM THEN UNTIL THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...HAL
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
102 PM EDT THU SEP 4 2014
.UPDATE...
ISSUED AT 1255 PM EDT THU SEP 4 2014
HOURLY GRIDS WERE UPDATED BASED ON RECENT OBSERVATIONS AND MODEL
TRENDS. THE RECENT HRRR RUNS HAVE A DECENT HANDLE ON THE SCENARIO AT
THIS TIME. POPS WERE RAISED ACROSS MUCH OF THE CWA MOSTLY INTO THE
SCATTERED CATEGORY...WITH ISOLATED POPS INTRODUCED ACROSS THE
BLUEGRASS COUNTIES. THE MOISTURE RETURN NORTH HAS BROUGHT A PLUME OF
DEEP MOISTURE WITH PW OF 1.8 INCHES OR MORE INTO THE KY/TN/VA TRI
STATE AREA...THOUGH PW IS GENERALLY 1.5 INCHES OR MORE ACROSS MOST OF
THE CWA. ANY THUNDERSTORMS THIS AFTERNOON WILL BE CAPABLE OF LOCALLY
HEAVY DOWNPOURS...AND IF THEY PERSIST SOME LOCALLY HEAVY RAINFALL. SO
FAR THE HEAVIEST RAINFALL HAS FALLEN FROM MORE PERSISTENT SHOWERS AND
THUNDERSTORMS IN PARTS OF THE CUMBERLAND VALLEY REGION.
SHOWERS AND THUNDERSTORMS SHOULD PEAK IN COVERAGE LATER THIS
AFTERNOON AND EARLY THIS EVENING AND THEN WANE TOWARD SUNSET...AS
THE UPPER LEVEL DISTURBANCE MOVING ACROSS THE OH VALLEY REGION
BEGINS TO DEPART TO THE NORTH AND EAST AND THE DEEPEST MOISTURE IS
ALSO SHUNTED TO THE EAST AND SOUTHEAST OF THE REGION.
UPDATE ISSUED AT 1019 AM EDT THU SEP 4 2014
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
TRENDS. A FRESH ZFP WAS ALSO ISSUED TO GET RID OF MORNING FOG WORDING
AS SATELLITE IMAGERY AND OBSERVATIONS INDICATE THAT VALLEY FOG
CONTINUES TO LIFT. THE FOG HAS LIFTED INTO A STRATUS DECK IN SOME
RIVER VALLEY LOCATIONS AND NEAR A FEW AREA LAKES...THIS ALSO IS
GRADUALLY ERODING AWAY.
RATHER LIGHT SOUTHWESTERLY FLOW WILL BRING INCREASING MOISTURE TO THE
AREA BELOW 500 MB. THERE IS ALSO A SHORTWAVE TROUGH OR WEAKNESS
BETWEEN RIDGING CENTERED NEAR BERMUDA AND ACROSS THE SOUTHEASTERN
STATES AND ANOTHER UPPER LEVEL RIDGE CENTERED IN THE MS VALLEY
REGION. THIS SHORTWAVE WILL WORK ACROSS THE REGION TODAY AND INTO
THIS EVENING. THE COMBINATION OF CURRENT RATHER STRONG SFC HEATING
AND THE INCREASING MOISTURE ALONG WITH THE WEAK SHORTWAVE TO MOVE
ACROSS THE AREA SHOULD BRING ISOLATED TO SCATTERED CONVECTION TO
PARTS OF THE REGION FROM MIDDAY INTO THE EVENING HOURS. THE CHANCES
FOR CONVECTION STILL APPEAR TO BE HIGHEST NEAR THE VA BORDER WITH
DEEPER MOISTURE THERE.
UPDATE ISSUED AT 758 AM EDT THU SEP 4 2014
HAVE UPDATED THE FORECAST GRIDS BASED ON LATEST OBS...BUT WITH NO
SUBSTANTIAL EFFECT ON THE OVERALL FORECAST.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 352 AM EDT THU SEP 4 2014
LIGHT WINDS...CLEAR TO PARTLY CLOUDY SKIES...AND A MOIST AIR MASS
HAVE ALLOWED TYPICAL SEASONAL VALLEY FOG TO DEVELOP EARLY THIS
MORNING. IT WILL DISSIPATE DURING THE MORNING...BUT GO THROUGH ITS
CYCLE AGAIN TONIGHT/FRIDAY. SOMEWHAT DRIER AIR MADE IT INTO THE FAR
NORTHERN PART OF THE FORECAST AREA ON WEDNESDAY AFTERNOON...BUT WILL
NOT GET ANY FURTHER SOUTH. LOW LEVEL FLOW WILL CARRY MOISTURE NORTH
AND NORTHEAST...ENSURING ALL AREAS ARE UNCOMFORTABLY HUMID TODAY
THROUGH FRIDAY. THE HUMIDITY MAY FUEL DEVELOPMENT OF A FEW SHOWERS
AND THUNDERSTORMS EACH AFTERNOON. THE GREATEST PROBABILITY WILL BE
NEAR THE VA BORDER...WHERE MOISTURE WILL BE THE DEEPEST. FURTHER
NW...FORECAST SOUNDINGS SHOW THE MOISTURE BEING MORE SHALLOW...WITH
DRY AIR ALOFT BEING LESS SUPPORTIVE OF SUSTAINED CONVECTION IN THE
ABSENCE OF DYNAMIC SUPPORT. IN ADDITION...WARMER MID LEVEL TEMPS IN
OUR NW COUNTIES WILL ALSO MAKE IT MORE DIFFICULT TO GET DEEP
CONVECTION THIS AFTERNOON. WINDS ALOFT WILL BE WEAK THROUGH THE
PERIOD...AND LITTLE ORGANIZATION OF CONVECTION IS EXPECTED...HELPING
TO LIMIT COVERAGE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 AM EDT THU SEP 4 2014
BIG WEATHER CHANGE STILL ANTICIPATED THIS COMING WEEKEND AS MODELS
REMAIN IN FAIRLY GOOD AGREEMENT. THE ONLY CHANGE WAS THAT MODELS
HAVE SLOWED DOWN THE COLD FRONT A TAD...WHICH COULD NOW IMPACT THE
FORECAST FOR SUNDAY. STARTING OFF THE PERIOD...DIURNALLY DRIVEN
CONVECTION WILL DIE OFF EARLY FRIDAY EVENING...LEAVING DRY
CONDITIONS FOR MUCH OF THE AREA THROUGH THE OVERNIGHT HOURS. THE
EXPECTED COLD FRONT WILL MARCH INTO NORTHERN KENTUCKY BY MIDDAY
SATURDAY AND SWING SOUTH THROUGH THE AFTERNOON AND EVENING HOURS.
THIS WILL YIELD WIDESPREAD SHOWERS AND THUNDERSTORMS. HOWEVER...WITH
THE MODELS SLOWING DOWN THE FRONT...LOOKS LIKE PRECIPITATION COULD
LINGER INTO SATURDAY NIGHT AND EVEN INTO SUNDAY BEFORE ENDING LATE
IN THE DAY ON SUNDAY. INSTABILITY SHOULD STILL DROP OFF OVERNIGHT
SATURDAY NIGHT...SO THUNDER CHANCES WILL DIMINISH...BUT RAIN SHOWERS
MAY PERSIST. THIS COULD SET UP A BIT WETTER AND CERTAINLY CLOUDIER
SUNDAY FOR THOSE ACROSS THE SOUTH AND SOUTHEAST. REGARDLESS...HIGHS
WILL ONLY REACH THE LOW TO MID 70S WITH THE ADDED CLOUD COVER AND
COLD ADVECTION BEHIND THE FRONT. SUNDAY NIGHT WILL BE MUCH COOLER AS
TEMPERATURES INTO THE 50S ARE EXPECTED.
WHILE HIGH PRESSURE WILL BEGIN TO BUILD OVER THE AREA EARLY NEXT
WEEK...SOME MOISTURE WILL REMAIN OVER EASTERN KENTUCKY...SUPPORTING
AN ISOLATED SHOWER OR TWO. HOWEVER...INSTABILITY IS WEAK...AND FLOW
ON MONDAY MAY BE FROM A SOUTHEAST DIRECTION...LEADING TO
DOWNSLOPING...WHICH COULD SQUASH ANYTHING FROM FORMING. FOR
NOW...WILL GO WITH A 20 POP TO COVER THE SMALL CHANCE. MODELS START
DIVERGING QUITE A BIT AND HAVE STARTING TO FLIP FLOP ON VARIOUS
SOLUTIONS AS WE HEAD TOWARDS TUESDAY. AT THIS TIME...OPTING TO KEEP
EACH DAYTIME PERIOD WITH LOW POPS WITH LOWER COVERAGE AT NIGHT UNTIL
WE SEE BETTER AGREEMENT WITH OUR NEXT WEATHER MAKER.
THUS...CONFIDENCE IN THE FORECAST BEYOND MONDAY IS VERY LOW. IT DOES
LOOK LIKE TEMPERATURES SHOULD REBOUND A BIT AS WE HEAD THROUGH NEXT
WEEK...BUT THE EXTREME WARMTH SHOULD STAY AWAY FOR A LITTLE WHILE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 758 AM EDT THU SEP 4 2014
FOG WAS EXTENSIVE IN THE VALLEYS WITH RIVERS OR LARGE STREAMS...AND
HAD CREPT OUT OF OUT TO SOME OF THE OPEN TERRAIN AND RIDGES. TAF
SITES HAVE BEEN HIGHLY VARIABLE. THE FOG WILL DISSIPATE BY LATE THIS
MORNING...LEAVING MOSTLY VFR THROUGH THE REST OF THE PERIOD. THERE
MAY BE SOME SHOWERS OR THUNDERSTORMS DURING THE AFTERNOON...BUT THEY
WILL BE SPARSE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...HAL
LONG TERM...KAS
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
357 PM EDT THU SEP 4 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU SEP 4 2014
AS FIGURED IT HAS BEEN A FAIRLY ACTIVE NIGHT AT LEAST IN TERMS OF
SHRA/TSRA. NO SEVERE WEATHER IN OUR CWA...WITH BULK OF TSRA STAYING
MAINLY OVER SOUTHERN CWA EARLIER TONIGHT. VERY HEAVY RAIN DID OCCUR
EARLIER AS KIMT AND KMNM BOTH ENDED UP WITH AROUND AN INCH OF RAIN
IN 45-60 MIN. STRONGEST STORMS IN THE AREA NOW ARE CROSSING CNTRL LK
MICHIGAN. A LULL HAS DEVELOPED OVER UPR MICHIGAN...EXCEPT VERY FAR
EAST WHERE RAIN AND EMBEDDED TSRA WILL RUN ITS COURSE OVER NEXT
COUPLE HOURS.
WESTERLY FLOW ALOFT AND THE MAIN SHORTWAVE IS DRIVING ACROSS
SOUTHERN SASKATCHEWAN AND INTO WESTERN NORTH DAKOTA. SPC
MESOANALYSIS PAGE SHOWS ISOLD-SCT STRONG-SEVERE STORMS OVER NORTH
DAKOTA ARE FORMING IN WARM AIR ADVECTION REGION ALONG AND NORTH OF
GRADIENT OF 1-6KM MUCAPE OF 2000-3000 J/KG MAXIMIZED FM SOUTHERN TO
CENTRAL PLAINS. ACTIVITY IS ALSO JUST NORTH OF THE +12C ISOTHERM AT
H7. CONVECTIVELY INDUCED WAVE IS ALSO FORMING OVR NORTH DAKOTA PER
WV LOOP AND REGIONAL RADAR LOOPS. HIGH RES MODELS...SUCH AS THE HRRR
AND NSSL WRF AND WRF-ARW/NMM BEGAN TO PICK UP ON THIS LATE WED
EVENING AND CONTINUE TO INDICATE THIS MCV WITH ASSOCIATED MCS WILL
CONTINUE TRACKING EAST ALONG MUCAPE/H85 DWPNT GRADIENT AND WITH THE
H85-H3 WEST TO EAST ORIENTED THICKNESS LINES AND FOLLOWING THE
FORWARD PROPAGATING CORFIDI VECTORS. CERTAINLY POSSIBLE THIS COMPLEX
MAY GROW UPSCALE/PRODUCE WIDESPREAD SEVERE WX GIVEN THE SUFFICIENT
EFFECTIVE SHEAR OVER 40 KTS PRESENT FM DAKOTAS ACROSS MINNESOTA AND
ALSO DUE TO THE FAVORABLE 0-3KM SHEAR OVER 30 KTS THAT WOULD HELP
THE SHEAR/COLD POOL BALANCE NEEDED TO SUSTAIN SUCH A COMPLEX. SFC
WARM FRONT STILL WELL TO THE SOUTHWEST OF HERE THIS MORNING...MOST
LIKELY OVER SOUTHERN MINNESOTA TO SOUTHWEST WISCONSIN. SEEMS THAT
THIS COMPLEX WOULD HAVE TO TAKE A VERY HARD TURN RIGHT...AND QUICKLY
FOR IT TO NOT IMPACT UPR GREAT LAKES LATER THIS MORNING OR MAYBE NOW
AS LATEST HRRR SHOWS...EARLY AFTN. THE LATER ARRIVAL OF A COMPLEX...
ALSO A GREATER SEVERE THREAT FOR WIND/HAIL OVER OUR CWA. CONFIDENCE
IS NOT HIGH ENOUGH TO PUT SEVERE MENTION IN GRIDS...BUT WILL CONTINUE
TO MENTION IN HWO AND VARIOUS SOCIAL MEDIA.
UNFORTUNATELY...SINCE THIS AREA OF TSRA IS A NEW DEVELOPMENT
COMPARED TO EXPECTED SHRA/TSRA EVOLUTION FOR TODAY LOOKED LIKE
12-24 HR AGO HAD TO REWORK POPS/WX CONSIDERABLY THROUGH MID AFTN
TODAY. WHATEVER COMPLEX WORKS ACROSS UPR MICHIGAN SHOULD BE ON THE
WANE AFT 18Z-21Z. WARM FRONT PROBABLY WILL HAVE TOUGH TIME MAKING IT
TO THE CWA TODAY GIVEN THE SHRA/TSRA THAT WENT THROUGH OVERNIGHT AND
THIS ADDITIONAL AREA OF TSRA POSSIBLE LATER TODAY. CAPPING THAT
LOOKED SO FIERCE FOR THIS AFTN 24 HR AGO...NOW NOT AS MUCH...
POSSIBLY BECAUSE THE ATMOSPHERE WILL BE WORKED OVER FROM SHRA/TSRA
MOVING IN FM NORTH DAKOTA LATER TODAY. THUS...THINK THAT THE H85
MOISTURE TRANSPORT INTO AN AREA OF MID-LEVEL FGEN WILL BE ENOUGH TO
REDEVELOP SHRA/TSRA OVER WESTERN CWA BY LATE THIS AFTN. ADDITIONAL
POTENTIAL FOR SEVERE WITH THIS ACTIVITY AS WELL GIVEN MLCAPES AROUND
1500 J/KG AND EFFECTIVE SHEAR 40-55 KTS. SUPERCELL STRUCTURES WOULD
STILL BE POSSIBLE WITH RIGHT MOVING SUPERCELLS SHOWING A WEST-EAST
MOTION WHILE LEFT MOVERS WOULD MOVE MORE SOUTHWEST TO NORTHEAST.
MEAN STORM MOTION WOULD BE WEST SOUTHWEST TO EAST NORTHEAST. ALL
MOTIONS ARE SWIFT...PROBABLY IN THE 30-40 MPH RANGE.
IN REGARDS TO SPECIFIC SEVERE POTENTIAL...SPC HAS OUR AREA FIRMLY IN
THE 15 PCT RISK FOR SEVERE HAIL AND DAMAGING WINDS. THIS COULD OCCUR
WITH THIS INITIAL COMPLEX IF IT MAKES INTO THE AREA. LIKELY DAMAGING
WINDS WOULD BE THE MAIN THREAT IF THAT OCCURS. IF ADDITIONAL STORMS
CAN REDEVELOP IN WAKE OF THIS ACTIVITY LATE THIS AFTN/EARLY THIS
EVENING AHEAD OF STRONG COLD FRONT...THE DEGREE OF SHEAR INDICATES
SUPERCELLS WOULD BE POSSIBLE ESPECIALLY IF MLCAPES RECOVER TOWARD
1500-2000 J/KG. ALL SEVERE MODES COULD OCCUR LATE THIS AFTN IF THAT
OCCURS...EVEN POTENTIAL FOR TORNADOES AS 0-1KM SHEAR IS OVER 30 KTS
AND ML LCL/S HEIGHTS WOULD BE VERY FAVORABLE AT LESS THAN 1000M.
FREEZING LEVELS MAINLY BLO 13KFT AND MODELS INDICATE WOULD HAVE TO
SEE CORES GET TO 30-35KFT FOR QUARTER SIZED HAIL. THIS SEEMS VERY
ACHIEVABLE GIVEN THE SHEAR AND INSTABILITY FORECAST. THE WILD CARD IS
EXTENT OF INSTABILITY THAT WILL BE LEFT IN WAKE OF THE INITIAL
COMPLEX. MODELS COULD BE OVERPLAYING THAT...AND THUS THE ADDITIONAL
SEVERE THREAT. TIME WILL TELL.
LARGER SCALE FORCING IN TERMS OF SHORTWAVE AND DEEP LAYER LIFT
SWINGS ACROSS THE CWA FM WEST TO EAST AND EXPECT SCT-NMRS SHOWERS
AND TSRA IN THE EVENING. MAY BE AT LEAST SOME LINGERING RISK OF
STRONGER STORMS DURING THIS TIME. DRYING PUNCHES IN IN MID-LEVELS
OVERNIGHT AND COLD FRONT ARRIVES. EXPECT SHRA/TSRA CHANCES TO BE
WANING OVER THE EAST CWA AFTER 08Z.
FINALLY...GRADIENT WINDS WILL BE VERY GUSTY...FIRST OVER NORTHERN LK
MICHIGAN TODAY IN THE SOUTH-SOUTHWEST FLOW...THEN LATE TONIGHT OVER
LK SUPERIOR IN WAKE OF THE FRONT WHEN WINDS SHIFT TO THE WEST
NORTHWEST. ISALLOBARIC ADDITION TO THE WIND COULD LEAD TO MARGINAL
GALES IN BOTH OF THESE AREAS...AT LEAST FOR A FEW HOURS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 357 PM EDT THU SEP 4 2014
NAM SHOWS A BROAD 500 MB TROUGH OVER THE NORTHERN PLAINS AND UPPER
GREAT LAKES 00Z SAT. THIS TROUGH MOVES THROUGH FRI NIGHT. LOOKS
QUIET THIS FORECAST PERIOD WITH A SHORTWAVE MOVING BY WELL NORTH OF
US FRI NIGHT AND SAT. WILL NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST FOR TEMPERATURES OR WEATHER.
IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB RIDGE ACROSS THE
SOUTHERN HALF OF THE U.S. WITH BROAD TROUGHING ACROSS THE NORTHERN
HALF OF THE U.S. 12Z MON. THERE IS A SHORTWAVE OVER THE NORTHERN
PLAINS 12Z MON. THIS SHORTWAVE MOVES INTO THE UPPER GREAT LAKES 12Z
TUE AND PASSES THROUGH THE AREA TUE NIGHT. MORE TROUGHING THEN SETS
UP TO THE WEST FOR THU AS THE UPPER PATTERN BECOMES MORE AMPLIFIED.
TEMPERATURES WILL COOL DOWN TO NEAR NORMAL FOR THIS FORECAST PERIOD.
WILL REMAIN DRY INTO MONDAY WITH A SFC FRONT AFFECTING THE AREA
THROUGH THU AND WILL KEEP IN SOME LOW CHANCE POPS FOR THIS FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 149 PM EDT THU SEP 4 2014
VERY COMPLICATED SHORT TERM FORECAST FOR ALL SITES. GENERAL VFR
CONDITIONS EXPECTED AT IWD AND SAW THROUGH LATE AFTERNOON...AND MVFR
CONDITIONS AT CMX. A COLD FRONT WILL THEN BRING A ROUND OF SHOWERS
AND THUNDERSTORMS FOR ALL SITES THIS EVENING. CONFIDENCE REMAINS LOW
ON HOW WIDESPREAD COVERAGE WILL BE...BUT ANYTHING THAT DEVELOPS IS
EXPECTED TO BE STRONG WITH POSSIBLE HAIL AND WIND GUSTS OVER 50KTS.
DUE TO THE LACK OF CONFIDENCE IN TIMING...PROVIDED A FOUR HOUR
WINDOW IN THE TAF...THOUGH DO NOT EXPECT CONVECTION TO LAST FOR MORE
THAN AN HOUR OR TWO. GUSTY NW WINDS TO 25KTS FOR IWD AND SAW...AND
30KTS FOR CMX ARE EXPECTED BEHIND THE COLD FRONT LATE TONIGHT
THROUGH FRIDAY MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 PM EDT THU SEP 4 2014
ONGOING SEICHE ON LAKE SUPERIOR FROM THUNDERSTORMS TODAY WILL
CONTINUE TONIGHT WITH FLUCTUATIONS IN WATER LEVELS OF 1 TO 2 FEET
CONTINUING THIS EVENING. IT WILL TAKE A WHILE TO DAMPEN OUT AND
PROBABLY WILL CONTINUE FOR SEVERAL DAYS. A COLD FRONT MOVING EAST
ACROSS LAKE SUPERIOR TONIGHT WILL BRING GUSTY WESTERLY WINDS TO
30KTS FRIDAY WITH A FEW GALE FORCE GUSTS ACROSS CENTRAL LAKE
SUPERIOR. STRONGER WINDS AGAIN ARRIVE TUE NIGHT WITH EAST WINDS UP
TO 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
COASTAL FLOOD WARNING UNTIL MIDNIGHT EDT TONIGHT FOR MIZ004>007.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...07
AVIATION...KLUBER
MARINE...07
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
209 PM EDT THU SEP 4 2014
LATEST UPDATE...
MESOSCALE DISCUSSION
.MESOSCALE DISCUSSION...
ISSUED AT 209 PM EDT THU SEP 4 2014
AN IMPRESSIVE LOOKING BOWING LINE OF THUNDERSTORMS WITH A HISTORY
OF WIND DAMAGE AND LARGE HAIL REPORTS IS RACING EAST SOUTHEAST
AROUND 55 MPH. THE CURRENT TRACK WOULD KEEP MOST OF THE STORM NEAR
AND NORTH OF ROUTE 10. IT SHOULD BE NOTED THE STORMS HAVE MOVED
AWAY FROM THE BEST INFLOW...DEEP LAYER SHEAR AND INSTABILITY. AS
SUCH I WOULD EXPECT THE LINE TO WEAKEN AS IT MOVES ONSHORE IN
BY 230 PM. EVEN SO THE SPC SREF SHOWS 35 TO 50 KNOTS OF EFFECT
SHEAR OVER THE STORMS SO THIS LINE WILL NOT TOTALLY DISSIPATE. AS A
RESULT I HAVE PUT LIKELY POPS OVER OUR NORTHERN ROW OF COUNTIES. I
MAY HAVE INCREASE POPS ANOTHER ROW OF TWO SOUTH WITHIN THE NEXT
HOUR.
&&
.SYNOPSIS...
ISSUED AT 330 AM EDT THU SEP 4 2014
AN ACTIVE WEATHER PATTERN IS TAKING SHAPE FROM TODAY THROUGH FRIDAY
EVENING. A WARM FRONT WILL BRING CHANCES FOR SHOWERS AND STORMS
ESPECIALLY THIS MORNING. ADDITIONAL SHOWERS AND STORMS ARE EXPECTED
TONIGHT THROUGH FRIDAY. THE RAIN SHOULD END FROM NORTH TO SOUTH
ACROSS SOUTHWEST LOWER MICHIGAN FRIDAY NIGHT AS A COLD FRONT DROPS
SOUTH THROUGH THE REGION. LOCALLY HEAVY RAIN IS A DISTINCT
POSSIBILITY. IT SHOULD BECOME QUITE WARM THIS AFTERNOON WITH
READINGS RISING INTO THE MIDDLE TO UPPER 80S IN MANY LOCATIONS. A
COOLER WEEKEND IS ANTICIPATED BEHIND THE COLD FRONT WITH HIGHS IN
THE LOWER 70S.
&&
.UPDATE...
ISSUED AT 1152 AM EDT THU SEP 4 2014
I LOWERED THE FORECAST HIGH TEMPERATURES TO THE 80 TO 85 DEGREE
RANGE AND RAISED THE POP TO NEAR CONDITIONAL INTO LATE MORNING. I
THEN ALLOWED THE POP TO TAIL OFF TO BELOW 15 PCT BY MID AFTERNOON
AS MORE STABLE AIR MOVES INTO THE AREA.
OUR MCV THAT ROLLED THROUGH OUR CWA HAS CREATED A WAKE LOW FEATURE
AND THE ENTIRE COMPLEX IS SINKING SOUTHEAST WITH TIME. THIS
RESULTED IN SOME LOCALLY HIGH WINDS. MEANWHILE THE RAP MODEL
SHOWS THE MCV TRACKING ESE INTO SE LOWER MICHIGAN/NORTHWEST OHIO
BY MID AFTERNOON. MEANWHILE THERE IS STRONG PUSH OF HOT AIR AT MID
LEVEL BEING ADVECTED IN BEHIND THE WARM FRONT. RAP MODEL SOUNDING
SHOW THE AIR OVER SOUTHWEST LOWER MICHIGAN BECOMING VERY STABLE
WITH CIN VALUES OVER 250 J/KG BY 00Z AS A RESULT OF THAT DEEP PUSH
OF HOT AIR. THIS WILL END ALL PRECIPITATION BY EARLY AFTERNOON AND
ALLOW THE SUN TO FINALLY COME OUT AND HEAT THE AIR. EVEN
SO...GIVEN HOW CLOUDY IS IS NOW...HARD TO IMAGINE IT WILL GET MUCH
WARMER THAN THE MID 80S... SO I LOWERED THE FORECAST HIGH FROM THE
UPPER 80S TO THE MID 80S.
THE LOW LEVEL JET SETS UP AGAIN TONIGHT BUT THE AXIS OF IT IS
NORTH OF HTL. THE MOISTURE TRANSPORT VECTORS IN THE 1000/850 LAYER
ARE MORE IMPRESSIVE TONIGHT THAN LAST NIGHT BUT THEY ARE FOCUSED
NEAR TVC. GIVEN THE CAPE DUE TO THE WARM AIR ALOFT I HAVE TO
WONDER HOW MUCH OF THE CONVECTION FROM WI/UPPER MICHIGAN WILL MAKE
IT SOUTH INTO THE GRR CWA. WE WILL HAVE TO LOOK MORE CLOSELY AT
THAT LATER.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 330 AM EDT THU SEP 4 2014
AREAL EXTENT AND TIMING OF THUNDERSTORMS IS THE BIGGEST CHALLENGE
WITH THE FORECAST THIS MORNING. SHOWERS AND STORMS ARE CURRENTLY
DEVELOPING TO OUR WEST IN A ZONE OF SOLID MOISTURE ADVECTION AT
850MB/S. THIS PUSH OF MOISTURE SURGES INTO THE AREA THIS MORNING AND
WILL BRING THE CHANCE OF SHOWERS AND STORMS TO ALL AREAS. A BIT OF A
LULL IS EXPECTED THIS AFTERNOON AS WE BREAK INTO THE WARM SECTOR OF
THE SYSTEM. AT LEAST PARTIAL CLEARING SHOULD ALLOW TEMPERATURES TO
PUSH WELL INTO THE 80S. GIVEN THE TIMING OF THE STORMS NOT EXPECTING
SEVERE WEATHER THIS MORNING.
THUNDERSTORMS SHOULD BECOME FAIRLY NUMEROUS AGAIN TONIGHT AS ANOTHER
SURGE OF MOISTURE ADVECTS INTO SOUTHWEST LOWER MICHIGAN. GIVEN
OVERNIGHT TIMING AGAIN...WE ARE NOT EXPECTING SEVERE WEATHER BUT IT
IS NOT OUT OF THE REALM OF POSSIBILITIES. IN FACT WE ARE ON THE
EASTERN EDGE OF A SLIGHT RISK AREA THAT CROSSES MASON INTO OCEANA
COUNTY. WIND AND HAIL WOULD BE THE MAIN THREATS.
FRIDAY INTO FRIDAY NIGHT...THE COLD FRONT PROGRESSES SOUTH THROUGH
THE AREA. THE LLJ PEELS AWAY TO THE EAST FRIDAY...BUT WE COULD BE
LOOKING AT STRONG DESTABILIZATION IN THE SOUTHERN HALF OF THE
FORECAST AREA. THE INSTABILITY ALONE MAY BE ENOUGH TO GENERATE SOME
SCATTERED SEVERE WEATHER. FEEL THE FRONT WILL AID IN FOCUSING STORMS
AND LOCALLY HEAVY RAINFALL AS WELL. THE RAIN SHOULD GRADUALLY TAPER
OFF FRIDAY EVENING FROM NORTH TO SOUTH.
SATURDAY WILL BE A MAINLY SUNNY AND DRY DAY WITH HIGHS IN THE LOWER
70S.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT THU SEP 4 2014
HIGH PRESSURE WILL BUILD IN TO BRING FAIR WEATHER WITH SEASONABLE
TEMPERATURES THIS WEEKEND WITH MAX TEMPS RANGING FROM THE UPPER 60S
TO MIDDLE 70S AND MIN TEMPS IN THE 40S TO LOWER 50S.
SOME CLOUDS WILL BEGIN TO MOVE IN MONDAY AS SOUTHERLY FLOW DEVELOPS
AND RESULTS IN GRADUALLY INCREASING MOISTURE ON THE BACK SIDE OF THE
DEPARTING HIGH PRESSURE RIDGE. DRY WEATHER WILL CONTINUE MONDAY
THROUGH MONDAY NIGHT.
DEVELOPING LOW PRESSURE AND A WARM FRONT WILL BRING POTENTIAL FOR
RAIN AND THUNDERSTORMS AS EARLY AS TUESDAY WITH A LITTLE BETTER
CHANCE FOR PRECIPITATION TUESDAY NIGHT THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 754 AM EDT THU SEP 4 2014
AREA OF SHOWERS AND THUNDERSTORMS WILL WORK THROUGH THE TAF SITES
THROUGH MIDDAY...ENDING FROM NORTHWEST (KMKG) TO SOUTHEAST (KJXN)
BETWEEN 13Z AND 16Z OR SO. THE EXPECTATION IS THAT THE SHOWERS AND
STORMS WILL TAPER OFF THIS MORNING WITH SKIES CLEARING OUT THIS
AFTERNOON. MAINLY VFR CONDITIONS ARE IN PLACE WITH HIGH BASED
STORMS OCCURRING. SOME BRIEF PERIODS OF MVFR CAN BE EXPECTED IN
THE HEAVIER STORMS. VFR SHOULD PREVAIL THIS AFTERNOON AS WE TRY TO
SCATTER OUT.
WINDS WILL PICK UP THIS MORNING FROM THE SOUTH-SOUTHWEST AT 10-25
KNOTS. THE HIGHEST WINDS WILL BE SEEN AT KMKG.
OVERNIGHT ANOTHER ROUND OF SHOWERS AND STORMS ARE EXPECTED TO WORK
THROUGH THE TAF SITES...AFTER 04Z TO 06Z. CEILINGS AND
VISIBILITIES MAY DIP INTO THE MVFR CATEGORY AGAIN...BUT AT THIS
POINT JUST MENTIONED VCTS WORDING.
&&
.MARINE...
ISSUED AT 1152 AM EDT THU SEP 4 2014
BASED ON EARLIER MARINE OBSERVATIONS AS THE STORMS WERE MOVING
THROUGH I EXPANDED THE SMALL CRAFT ADVISORY FARTHER SOUTH. THE
PORT SHELDON BUOY AT 1120 AM STILL HAD GUSTS TO 29 KNOTS WITH 6
FOOT WAVES. SOUTH HAVEN AT GUSTS AS HIGH AS 33 KNOTS BUT THAT HAS
SINCE DIMINISHED TO 15 TO 20 KNOTS. WEB CAMS FROM PORT
SHELDON...GRAND HAVEN...AND MUSKEGON SHOW WHITE CAPS ON THE WATER
WITH 4 TO 6 FOOT WAVES (BUOY DATA). SO BOTTOM LINE IT MAKES SENSE
TO KEEP THE KEEP THE ADVISORY AND BEACH HAZARD STATEMENT GOING.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT THU SEP 4 2014
PERIODS OF THUNDERSTORMS ARE EXPECTED FROM THIS MORNING THROUGH
FRIDAY EVENING. PWAT VALUES RISE INTO THE 1.50 TO 2.00 INCH RANGE AS
SOUTHERLY FLOW STREAMS IN DEEP MOISTURE. THE DEEPEST MOISTURE LOOKS
TO BE IN PLACE THURSDAY NIGHT THROUGH FRIDAY WHICH IS WHEN THE
HEAVIEST RAINS WILL LIKELY FALL. RIVER LEVELS REMAIN WELL WITHIN
BANK THOUGH...SO RIVER FLOODING IS NOT REALLY ANTICIPATED. SWATHS OF
1 TO 2 INCH RAINFALLS REMAIN A POSSIBILITY...ESPECIALLY ACROSS
CENTRAL LOWER MICHIGAN AND POTENTIALLY ALONG I94. EVEN WITH THESE
TOTALS WE ARE PROBABLY NOT LOOKING AT MUCH MORE THAN SOLID WITHIN
BANK RISES. REGARDING LOCALIZED AREAL FLOODING FROM THE STORMS
THEMSELVES...THIS REMAINS A POSSIBILITY AS WELL GIVEN THE DEEP
MOISTURE IN PLACE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY MORNING FOR MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT FRIDAY FOR LMZ844>849.
&&
$$
MESOSCALE...WDM
UPDATE...WDM
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...LAURENS
AVIATION...DUKE
HYDROLOGY...DUKE
MARINE...WDM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
108 PM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 1250 PM CDT THU SEP 4 2014
UPDATED TO INCLUDE 18Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM CDT THU SEP 4 2014
MAIN CONCERNS WITH THIS PERIOD ARE THE FORWARD PROPAGATING MCS
THAT IS EXPECTED TO DEVELOP AND RACE ACROSS CENTRAL MN EARLY
THIS MORNING. THIS WILL BE FOLLOWED BY HOT AND HUMID TEMPERATURES
ACROSS EASTERN MN AND WESTERN WI...WITH A FEW SHOWERS AND
THUNDERSTORMS POSSIBLE BY LATE AFTERNOON. MEANWHILE A SEASONABLY
STRONG COLD FRONT WILL PUSH THROUGH THE REGION AND BRING BREEZY
NORTHWESTERLY WINDS OVERNIGHT ALONG WITH COOL/DRY AIR.
THE FIRST ORDER OF DISCUSSION IS THE SEVERE WEATHER THREAT THIS
MORNING RELATED TO THE CONVECTION ACROSS NORTH DAKOTA. HIRES
MODELS SUCH AS THE HRRR AND 00/03Z RUNS OF THE HOPWRF ARE IN
REMARKABLE AGREEMENT THAT THIS CONVECTION WILL INTENSIFY AS IT
MOVES INTO WESTERN MINNESOTA AND DEVELOP INTO A BOW ECHO. THIS
STORM MODE SEEM VERY PLAUSIBLE CONSIDERING THE ORIENTATION OF THE
DEEP LAYER SHEAR VECTORS IN RELATION TO THE WARM FRONT AND MUCAPE
GRADIENT...SO INCLUDED DAMAGING WINDS IN THE FORECAST ACROSS THE
FAR NORTHERN TIER OF COUNTIES. THE HRRR SEEMS TO HAVE A BETTER
HANDLE ON THE ONGOING CONVECTION...AND IT KEEPS THE MAJORITY OF
THE FORECAST PRECIP NORTH OF THE CWA. HOWEVER BASED ON THE ACTUAL
LOCATION OF THE WARM FRONT STILL THINK THERE IS LEGITIMATE RISK
ALONG AND NORTH OF A LINE FROM ALEXANDRIA MN TO RICE LAKE WI.
AS THE COLD POOL BECOMES WELL ESTABLISHED THIS CONVECTION WILL
RACE EASTWARD. MEANWHILE THE UPPER LEVEL WAVE AND SURFACE LOW
WILL SLOWLY MAKE THEIR WAY INTO NORTHERN MN ALLOWING THE WARM
SECTOR TO DESTABILIZE THROUGHOUT THE DAY ON THURSDAY. DEPENDING ON
THE RESIDUAL CLOUD COVER...AFTERNOON HIGH TEMPS COULD EASILY CLIMB
INTO THE 90S ACROSS SOUTHEASTERN MN AND WESTERN WI. FOR NOW DID
NOT GO MUCH ABOVE GUIDANCE SINCE SHOWERS AND THUNDERSTORMS COULD
DEVELOP ALONG THE TRAILING COLD FRONT LIMITING THE DIABATIC
HEATING. A FEW OF THESE STORMS ARE LIKELY TO BE SEVERE AS FORECAST
SOUNDINGS SHOW NEARLY 4000J/KG OF CAPE BY LATE AFTERNOON AND
AROUND 30KTS OF DEEP LAYER SHEAR ALONG AND EAST OF THE MN/WI
BORDER.
THIS AFOREMENTIONED COLD FRONT IS THE LAST REAL AREA OF INTEREST.
AGAIN FORECAST SOUNDINGS SHOW STRONG COLD AIR ADVECTION IN THE
WAKE OF THE FRONT. THIS WILL KEEP THE BOUNDARY LAYER WELL MIXED
WITH NORTHWESTERLY WIND GUSTS OF 20 TO 30MPH EXPECTED TO PREVAIL
AFTER DARK. THEREFORE INCREASED THE WINDS THURSDAY NIGHT...AND
USED LESS BIAS-CORRECTED GRIDS FOR OVERNIGHT LOWS SINCE THE
TEMPERATURES SHOULD BE RATHER UNIFORM. ALSO RAISED CLOUD COVER
SINCE SOUNDINGS SHOW SATURATION ABOVE THE BOUNDARY LAYER.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 AM CDT THU SEP 4 2014
THE FIRST HALF OF THE LONG TERM LOOKS RATHER QUIET. THERE WILL BE
A SPLIT FLOW PATTERN DEVELOPING WITH THE SUBTROPICAL JET TO THE
SOUTH KEEPING THE HEAT CONFINED TO THE SOUTHERN STATES...AND THE
POLAR JET ACROSS CENTRAL CANADA KEEPING THE UNSEASONABLY COOL AIR
TO THE NORTH - AT LEAST FOR THE TIME BEING. SURFACE HIGH PRESSURE
WILL GUARANTEE MOSTLY CLEAR SKIES THROUGH SUNDAY NIGHT.
THINGS BECOME A BIT MORE COMPLEX NEXT WEEK AS THE POLAR JET
BEGINS TO SINK SOUTH. A MORE ACTIVE PATTERN IS IN THE OFFING WITH
SEVERAL DISTURBANCES SKIRTING ALONG THE NORTHERN TIER OF THE U.S.
HOWEVER...WITH THE SUBTROPICAL JET REMAINING SOUTH IT DOES NOT
APPEAR ANY OF THESE DISTURBANCES WILL HAVE A WHOLE LOT OF MOISTURE
TO WORK WITH. THEREFORE KEPT POPS IN THE CHC RANGE.
EVENTUALLY THE JETS WILL PHASE AND CARVE OUT A DEEP TROUGH OVER
CANADA AND THE NORTHERN U.S. SOME TIME DURING THE MIDDLE OF NEXT
WEEK. THE MUCH COOLER TEMPS ACCOMPANYING THIS TROUGH SHOULD MARK
THE FIRST CRACK AT AUTUMN WEATHER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1250 PM CDT THU SEP 4 2014
MAIN CONVECTION FROM THE MORNING HAS SHIFTED INTO THE GREAT LAKES
REGION WHILE SCATTERED SHOWERS HAVE DEVELOPED THIS AFTN OVER
MAINLY SWRN MN IN THE WAKE OF THE MORNING ACTIVITY. THIS IS IN
RESPONSE TO THE CDFNT MAKING PROGRESS INTO WRN MN THIS AFTN AND
MODEST INSTABILITY AND WEAK CAPPING REMAINING OVER MUCH OF MN.
PRECIP COVERAGE LOOKS TO BE SCATTERED AT BEST...WITH POSSIBLY SOME
ISOLD EMBEDDED TSTMS...BUT UNTIL TSTMS SHOW BETTER COVERAGE IT IS
DIFFICULT TO ADVERTISE AS SUCH IN THE TAFS SO HAVE GONE MAINLY
-SHRA WITH MVFR FLIGHT CONDS. CONDS IMPROVE THIS EVENING INTO THE
OVERNIGHT HRS AS WINDS SHIFT TO W-NW AND DRIER AIR WORKS ITS WAY
INTO THE AREA. SOME DISCREPANCIES EXIST AS TO THE COVERAGE AND
HEIGHT OF CLOUDS OVERNIGHT THRU DAYBREAK...BUT HAVE OPTED TO GO
MAINLY VFR OVERNIGHT THRU TMRW WITH NW FLOW DEVELOPING AND DRIER
AIR MOVING IN.
KMSP...WILL KEEP AN EYE OUT FOR POTENTIAL SCATTERED SHRA/TSTMS
THIS AFTN...PARTICULARLY BETWEEN INITIALIZATION TIME AND 22Z AS
THE ACTIVITY OVER SWRN MN SHIFTS NE. HAVE HELD OFF CB/TS MENTION
ATTM AS CHCS ARE LOW FOR CONVECTION AND COVERAGE IS VERY ISOLD.
WILL MONITOR AND AMEND AS NEEDED. OTHERWISE...CONDS IMPROVE THIS
EVE THRU OVERNIGHT AND WILL REMAIN VFR TNGT AND TMRW.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS W 5-10 KTS.
SUN...VFR. WINDS SW 5-10 KTS.
MON...MAINLY VFR. CHC MVFR IN SHRA/TSRA. WINDS S 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...JPC
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
311 PM CDT THU SEP 4 2014
.SHORT TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
CHANCE FOR SHOWERS AND STORMS TONIGHT...AND COOLER TEMPERATURES TO
FOLLOW...ARE THE PRIMARY SHORT RANGE FORECAST CONCERNS.
COLD FRONT WAS SLIPPING SOUTHEAST THROUGH THE CWA THIS AFTERNOON.
LATEST RAP ANALYSIS SHOWS INSTABILITY INCREASING AHEAD OF THE FRONT
WHERE MLCAPES WERE OVER 3000 J/KG ACROSS SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA. HOWEVER WARM MID LEVEL TEMPERATURES WERE PROVIDING A
CAP FOR STORMS AHEAD OF THE FRONT. BEHIND THE FRONT SCATTERED
SHOWERS AND STORMS HAD DEVELOPED IN SOUTHEAST SOUTH DAKOTA TIED TO
WAVE RIDING THROUGH THE NORTHERN PLAINS...BUT THOSE HAD MOVED OFF TO
THE NORTHEAST OR HAD DISSIPATED BY MID AFTERNOON. GIVEN CAPPING
ALONG AND AHEAD OF FRONT...SEEMS UNLIKELY WE WILL SEE DEVELOPMENT
THERE THIS AFTERNOON OR EVENING. BEHIND THE FRONT...MORE DEVELOPMENT
WILL HAVE TO WAIT UNTIL SHORTWAVE CURRENTLY MOVING INTO EASTERN
COLORADO MOVES INTO OUR AREA. LATEST SHORT RANGE MESOSCALE MODELS
SUGGEST THIS WILL NOT HAPPEN UNTIL LATE THIS EVENING...AND FOCUS ON
AREAS NEAR AND NORTHWEST OF INTERSTATE 80...WITH A GRADUAL DRIFT AND
EXPANSION TO THE SOUTHEAST DURING THE OVERNIGHT.
STRONGER MID LEVEL SHORTWAVE PROVIDING MID LEVEL FRONTOGENESIS IS
FORECAST TO OVERSPREAD THE REGION FRIDAY AFTERNOON AND EVENING
BEFORE MOVING OFF TO THE EAST FRIDAY NIGHT. WILL CONTINUE CHANCE FOR
SHOWERS MUCH OF FRIDAY WITH DECREASING CHANCES FRIDAY NIGHT.
SURFACE HIGH PRESSURE WITH NORTHWEST FLOW ALOFT WILL THEN TAKE OVER
AND BRING MILD AND DRY WEATHER FOR THE BULK OF THE WEEKEND. RETURN
FLOW SETTING UP ON SUNDAY COULD SPREAD MORE CLOUDS INTO THE
REGION...BUT WILL KEEP PRECIPITATION OUT OF THE FORECAST THROUGH THE
AFTERNOON.
COOLER WEATHER IS ALSO ON TAP FOR THE WEEKEND. TEMPERATURES AHEAD OF
COLD FRONT WERE IN THE 90S THIS AFTERNOON...WITH 70S OR EVEN 60S
NOTED IN SOUTH DAKOTA IN DEEPER COLD AIR BEHIND THE FRONT
CORRESPONDING TO 10C 850 TEMPERATURES. THAT AIR WILL SETTLE OVER OUR
AREA FRIDAY AND SATURDAY BEFORE WARMING TO NEAR 14C ON SUNDAY. MODEL
OUTPUT AGREES WITH OUR GOING FORECAST FOR UPPER 60S TO LOWER 70S
FRIDAY AND SATURDAY...WITH MID 70S OR SO ON SUNDAY. SEE NO REASON TO
MOVE FROM THOSE NUMBERS TOO MUCH.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
UPPER LEVEL FLOW PATTERN WILL BECOME MORE ZONAL FOR THE FIRST HALF
OF THE WEEK BEFORE LARGE UPPER TROUGH SETTLES INTO THE CONUS FOR THE
LATTER HALF. STRONG SHORTWAVE MOVING THROUGH THE PLAINS WILL BRING
RAIN CHANCES TO OUR AREA SUNDAY NIGHT THROUGH MONDAY BEFORE EJECTING
EAST MONDAY NIGHT. RETURN FLOW BEGINNING SUNDAY WILL PROVIDE PLENTY
OF MOISTURE FOR STORMS MONDAY AFTERNOON WHEN SURFACE-BASED CAPES
SHOULD TOP 2000 J/KG AND BULK 0-6KM SHEAR OVER 40KT. SEVERE STORMS
ARE POSSIBLE MONDAY AFTERNOON IF STORMS DO FIRE.
WITH WAVE EXITING TUESDAY...WE SHOULD SEE A DRY PERIOD UNTIL HEIGHTS
BEGIN TO LOWER WEDNESDAY WITH APPROACH OF DEEPER UPPER TROUGH
SETTLING INTO THE PLAINS. CORE OF UPPER TROUGH/LOW WILL MOVE INTO
THE NORTHERN PLAINS BY THURSDAY...AND WILL DRIVE A COLD FRONT
THROUGH OUR AREA WEDNESDAY. ANOTHER CHANCE FOR THUNDERSTORMS WILL
ACCOMPANY THAT FRONT...THEN MAINLY SHOWERS IN OVERRUNNING REGIME
BEHIND THE FRONT FOR WEDNESDAY NIGHT INTO THURSDAY.
TEMPERATURES WILL BE SLOWLY WARMING AHEAD OF WEDNESDAY COLD
FRONT...WITH HIGHS BETWEEN 75 AND 85...THEN MUCH COOLER THURSDAY
WITH HIGHS IN THE 60S.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1246 PM CDT THU SEP 4 2014
A COLD FRONT WILL CONTINUE TO DROP SOUTH OVER THE TAF SITES THIS
AFTERNOON TURNING SFC WINDS TO THE NORTHWEST. THE FRONT IS ALREADY
THROUGH KOFK...AND WILL BE THROUGH KOMA AND KLNK IN THE NEXT FEW
HOURS. AN MVFR DECK EXTENDS BEHIND THE FRONT AND WILL CONTINUE
INTO THE EVENING HOURS. CONVECTION IS LIMITED THIS AFTERNOON DUE
TO A STRONG CAP IN PLACE...BUT SHOWERS AND THUNDERSTORMS WILL
BECOME LIKELY AFTER DARK.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...KERN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
617 PM EDT THU SEP 4 2014
.SYNOPSIS...
A LOW WILL MOVE ACROSS ONTARIO TONIGHT AND INTO QUEBEC FRIDAY AND
FRIDAY NIGHT. A COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE
ACROSS THE AREA FRIDAY NIGHT. A RIDGE WILL BUILD IN SATURDAY NIGHT
AND LAST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
RADAR RETURNS GETTING AWFULLY CLOSE TO KTOL. THIS ACTIVITY SHOULD
DISSIPATE AFTER SUNSET BUT HAVE ADDED A SMALL MENTION TO LUCAS CO.
MADE THE SKY FORECAST MORE OPTIMISTIC FOR EASTERN AREAS.
PREVIOUS...THE CUMULUS WILL DISSIPATE QUICKLY. SOME MID AND HIGH CLOUDS
WILL BE AROUND. PARTLY CLOUDY SHOULD HANDLE IT. WENT TOWARD THE
WARMER GUIDANCE FOR LOWS BECAUSE OF THE DEW POINTS AND SOME WIND.
THE HRRR MODEL TRIES TO BRING SOME SPRINKLES OR SHOWERS INTO NW OH
BY EVENING...THIS IS THE REMNANTS OF THE SYSTEM FROM EARLIER. THIS
AREA IS DECREASING...WILL KEEP IT DRY.
THE NAM ESPECIALLY TRIES TO HINT AT SOME SHOWERS DEVELOPING OVER
NORTHWEST OHIO TOWARD DAYBREAK FRIDAY. THE GFS KIND OF HINTS AT THAT
TOO. AT THIS TIME KEEPING LATE TONIGHT DRY. THE NEXT SHIFTS WILL
HAVE TO MONITOR THIS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
A WEAK UPPER TROF WILL MOVE THROUGH IN THE MORNING...THIS MAY CAUSE
AN ISOLATED SHOWER OR SPRINKLE. THE BEST CHANCE WILL BE LATER IN THE
AFTERNOON AND EVENING AS THE COLD FRONT MOVES IN. THE BEST CHANCE
EXCEPT FOR NW OH WILL BE MAINLY AFTER MIDNIGHT AS MORE MOISTURE
COMES IN. SHOWERS AND THUNDERSTORMS WILL BEGIN DECREASING FROM THE
NORTH BY DAYBREAK AND THE DRYING SHOULD BE SOMEWHAT QUICK.
THE PRECIPITABLE WATER WILL BE AROUND 2 INCHES FRIDAY NIGHT. SOME OF
THE THUNDERSTORMS COULD BE STRONG WITH LOCALLY HEAVY RAIN. THE BEST
THREAT OF SEVERE WOULD BE OVER NORTHWEST OHIO IN THE EVENING AND
SEVERE WOULD BE ISOLATED AND VERY MARGINAL.
THE LAKE AND 850 MB TEMPERATURE DIFFERENCE BY SUNDAY MORNING WILL BE
NEAR 13C. SOME LAKE EFFECT CLOUDS WILL BE LIKELY. NOT EXPECTING ANY
SHOWERS BECAUSE OF SO MUCH RIDGING.
USED A BLEND OF GUIDANCE FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE LOCATED OVER NEW ENGLAND ON MONDAY...BUILDING
OFFSHORE ON MONDAY NIGHT. SOUTHEASTERLY RETURN FLOW BEHIND THE
DEPARTING HIGH WILL LEAD TO A GRADUAL INCREASE IN LOW LEVEL MOISTURE
FROM THE SOUTHEAST. BY TUESDAY WE SEE THE FIRST IN A SERIES OF
SHORTWAVES APPROACH THE OHIO VALLEY AND INTERACT WITH THIS MOISTURE
TO CAUSE A CHANCE OF SHOWERS AND THUNDERSTORMS. LONG RANGE MODELS
ARE STRUGGLING TO RESOLVE THESE SHORTWAVES AS WE TRANSITION FROM A
MORE ZONAL UPPER LEVEL FLOW OVER THE WEEKEND TO A BROAD TROUGH
THROUGH MIDWEEK. ADDED A CHANCE OF THUNDERSTORMS TO THE FORECAST ON
TUESDAY AND WILL LEAVE POPS IN THROUGH MIDWEEK WITH THE UNSETTLED
PATTERN SETTING UP. TEMPERATURES WILL BE TRICKY AND DEPEND ON
COVERAGE OF CLOUDS AND SHOWERS. TEMPERATURES START THE LONG TERM OFF
NEAR TO SLIGHTLY BELOW NORMAL...TRENDING COOLER TOWARDS DAY 7.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SHOWERS ACROSS INDIANA CONTINUE TO WEAKEN AS THEY MOVE EAST INTO
DRIER AIR. THE NEXT CHANCE FOR SHOWERS WILL NOT ARRIVE UNTIL LATE
TONIGHT WHEN A FEW SHOWERS COULD TRICKLE SOUTH OUT OF MICHIGAN AS
MOISTURE INCREASES AT TOL/FDY. CAN NOT ENTIRELY RULE OUT A
THUNDERSTORM BUT CHANCES ARE LOW. OTHERWISE VFR CONDITIONS WILL
CONTINUE UNTIL POSSIBLY LATE TONIGHT WHEN VISIBILITIES MAY DROP TO
4-6 MILES IN BR AS DEWPOINTS INCREASE BENEATH A SHALLOW INVERSION.
INCLUDED THE RESTRICTED VISIBILITY AT MFD/CAK/YNG ALTHOUGH THIS
MAY NOT OCCUR IF WINDS HOLD UP AROUND 5 KNOTS. SOUTHWEST WINDS
WILL INCREASE THROUGH THE MORNING AND BE BREEZY AT TIMES WITH
GUSTS OF 15-20 KNOTS ON FRIDAY AFTERNOON. CHANCES OF THUNDERSTORMS
DEVELOP BETWEEN 18-00Z ON FRIDAY AFTERNOON BUT RAMP UP MORE AFTER
00Z FRIDAY NIGHT.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS FRIDAY
NIGHT AND CONTINUING ON SATURDAY WITH SHOWERS ASSOCIATED WITH THE
COLD FRONT.
&&
.MARINE...
WINDS WILL REMAIN OUT OF THE SOUTH OVERNIGHT WITH SOUTHWEST WINDS
INCREASING TO 10 TO 15 KNOTS ON FRIDAY AHEAD OF AN APPROACHING COLD
FRONT. THE FRONT WILL PUSH SOUTH ACROSS THE AREA ON FRIDAY NIGHT
WITH WINDS SHIFTING TO THE NORTH BY EARLY SATURDAY. WAVES WILL
INCREASE TO 2 TO 3 FEET WITH THE NORTHERLY FLOW ON SATURDAY. HIGH
PRESSURE WILL BUILD EAST ACROSS THE GREAT LAKES FROM SATURDAY NIGHT
THROUGH MONDAY WITH GENERALLY LIGHT WINDS AND WAVE CONDITIONS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...KEC
AVIATION...KUBINA
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
347 PM EDT THU SEP 4 2014
.SYNOPSIS...
A LOW WILL MOVE ACROSS ONTARIO TONIGHT AND INTO QUEBEC FRIDAY AND
FRIDAY NIGHT. A COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE
ACROSS THE AREA FRIDAY NIGHT. A RIDGE WILL BUILD IN SATURDAY NIGHT
AND LAST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE CUMULUS WILL DISSIPATE QUICKLY. SOME MID AND HIGH CLOUDS WILL BE
AROUND. PARTLY CLOUDY SHOULD HANDLE IT. WENT TOWARD THE WARMER
GUIDANCE FOR LOWS BECAUSE OF THE DEW POINTS AND SOME WIND.
THE HRRR MODEL TRIES TO BRING SOME SPRINKLES OR SHOWERS INTO NW OH
BY EVENING...THIS IS THE REMNANTS OF THE SYSTEM FROM EARLIER. THIS
AREA IS DECREASING...WILL KEEP IT DRY.
THE NAM ESPECIALLY TRIES TO HINT AT SOME SHOWERS DEVELOPING OVER
NORTHWEST OHIO TOWARD DAYBREAK FRIDAY. THE GFS KIND OF HINTS AT THAT
TOO. AT THIS TIME KEEPING LATE TONIGHT DRY. THE NEXT SHIFTS WILL
HAVE TO MONITOR THIS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
A WEAK UPPER TROF WILL MOVE THROUGH IN THE MORNING...THIS MAY CAUSE
AN ISOLATED SHOWER OR SPRINKLE. THE BEST CHANCE WILL BE LATER IN THE
AFTERNOON AND EVENING AS THE COLD FRONT MOVES IN. THE BEST CHANCE
EXCEPT FOR NW OH WILL BE MAINLY AFTER MIDNIGHT AS MORE MOISTURE
COMES IN. SHOWERS AND THUNDERSTORMS WILL BEGIN DECREASING FROM THE
NORTH BY DAYBREAK AND THE DRYING SHOULD BE SOMEWHAT QUICK.
THE PRECIPITABLE WATER WILL BE AROUND 2 INCHES FRIDAY NIGHT. SOME OF
THE THUNDERSTORMS COULD BE STRONG WITH LOCALLY HEAVY RAIN. THE BEST
THREAT OF SEVERE WOULD BE OVER NORTHWEST OHIO IN THE EVENING AND
SEVERE WOULD BE ISOLATED AND VERY MARGINAL.
THE LAKE AND 850 MB TEMPERATURE DIFFERENCE BY SUNDAY MORNING WILL BE
NEAR 13C. SOME LAKE EFFECT CLOUDS WILL BE LIKELY. NOT EXPECTING ANY
SHOWERS BECAUSE OF SO MUCH RIDGING.
USED A BLEND OF GUIDANCE FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE LOCATED OVER NEW ENGLAND ON MONDAY...BUILDING
OFFSHORE ON MONDAY NIGHT. SOUTHEASTERLY RETURN FLOW BEHIND THE
DEPARTING HIGH WILL LEAD TO A GRADUAL INCREASE IN LOW LEVEL MOISTURE
FROM THE SOUTHEAST. BY TUESDAY WE SEE THE FIRST IN A SERIES OF
SHORTWAVES APPROACH THE OHIO VALLEY AND INTERACT WITH THIS MOISTURE
TO CAUSE A CHANCE OF SHOWERS AND THUNDERSTORMS. LONG RANGE MODELS
ARE STRUGGLING TO RESOLVE THESE SHORTWAVES AS WE TRANSITION FROM A
MORE ZONAL UPPER LEVEL FLOW OVER THE WEEKEND TO A BROAD TROUGH
THROUGH MIDWEEK. ADDED A CHANCE OF THUNDERSTORMS TO THE FORECAST ON
TUESDAY AND WILL LEAVE POPS IN THROUGH MIDWEEK WITH THE UNSETTLED
PATTERN SETTING UP. TEMPERATURES WILL BE TRICKY AND DEPEND ON
COVERAGE OF CLOUDS AND SHOWERS. TEMPERATURES START THE LONG TERM OFF
NEAR TO SLIGHTLY BELOW NORMAL...TRENDING COOLER TOWARDS DAY 7.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SHOWERS ACROSS INDIANA CONTINUE TO WEAKEN AS THEY MOVE EAST INTO
DRIER AIR. THE NEXT CHANCE FOR SHOWERS WILL NOT ARRIVE UNTIL LATE
TONIGHT WHEN A FEW SHOWERS COULD TRICKLE SOUTH OUT OF MICHIGAN AS
MOISTURE INCREASES AT TOL/FDY. CAN NOT ENTIRELY RULE OUT A
THUNDERSTORM BUT CHANCES ARE LOW. OTHERWISE VFR CONDITIONS WILL
CONTINUE UNTIL POSSIBLY LATE TONIGHT WHEN VISIBILITIES MAY DROP TO
4-6 MILES IN BR AS DEWPOINTS INCREASE BENEATH A SHALLOW INVERSION.
INCLUDED THE RESTRICTED VISIBILITY AT MFD/CAK/YNG ALTHOUGH THIS
MAY NOT OCCUR IF WINDS HOLD UP AROUND 5 KNOTS. SOUTHWEST WINDS
WILL INCREASE THROUGH THE MORNING AND BE BREEZY AT TIMES WITH
GUSTS OF 15-20 KNOTS ON FRIDAY AFTERNOON. CHANCES OF THUNDERSTORMS
DEVELOP BETWEEN 18-00Z ON FRIDAY AFTERNOON BUT RAMP UP MORE AFTER
00Z FRIDAY NIGHT.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS FRIDAY
NIGHT AND CONTINUING ON SATURDAY WITH SHOWERS ASSOCIATED WITH THE
COLD FRONT.
&&
.MARINE...
WINDS WILL REMAIN OUT OF THE SOUTH OVERNIGHT WITH SOUTHWEST WINDS
INCREASING TO 10 TO 15 KNOTS ON FRIDAY AHEAD OF AN APPROACHING COLD
FRONT. THE FRONT WILL PUSH SOUTH ACROSS THE AREA ON FRIDAY NIGHT
WITH WINDS SHIFTING TO THE NORTH BY EARLY SATURDAY. WAVES WILL
INCREASE TO 2 TO 3 FEET WITH THE NORTHERLY FLOW ON SATURDAY. HIGH
PRESSURE WILL BUILD EAST ACROSS THE GREAT LAKES FROM SATURDAY NIGHT
THROUGH MONDAY WITH GENERALLY LIGHT WINDS AND WAVE CONDITIONS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
326 PM EDT THU SEP 4 2014
.SYNOPSIS...
WEAK HIGH PRESSURE SLIDES EAST WITH INCREASING MOISTURE THROUGH
FRIDAY. COLD FRONT MOVES ACROSS SATURDAY AFTERNOON. FRONT SLOWS
DOWN AS IT CREEPS SOUTH OF AREA. WEAK HIGH PRESSURE SUNDAY AFTERNOON.
&&
.NEAR TERM /THROUGH FRIDAY/...
INCREASED POPS TO LIKELY PER LATEST RADAR IMAGES SHOWING SCATTERED
TO NUMEROUS SHOWERS WITH EMBEDDED THUNDERSTORMS AFFECTING THE
WESTERN SLOPES AND PORTIONS OF THE SOUTHERN COAL FIELDS THIS
AFTERNOON. THE STRONGER STORMS COULD PRODUCE 1 TO 2 INCHES PER
HOUR. WILL CONTINUE MONITORING RADAR TRENDS LOOKING FOR REPETITIVE
SHOWERS THAT COULD PRODUCE MINOR WATER PROBLEMS. RAINFALL ACTIVITY
SHOULD DIMINISH IN INTENSITY AND COVERAGE LATER THIS EVENING.
PREVIOUS DISCUSSION BELOW...
HIGH PRESSURE...OFF TO THE EAST...HAS ALLOWED FOR WARM AND MUGGY
WEATHER ACROSS THE REGION...WITH DEW POINTS ACROSS MUCH OF THE AREA
THIS AFTERNOON IN THE MID 60S TO LOWER 70S. SATELLITE PW ESTIMATES
AROUND 1.2 TO 1.4 INCHES ACROSS MUCH OF SOUTHWEST VA...WEST VA...AND
EASTERN KY...WITH LOWER PWS OF AROUND AN INCH ACROSS SOUTHEAST OHIO.
WITH THE LIGHT SOUTHERLY FLOW...AND THE HUMID UNSTABLE AIRMASS IN
PLACE...HAVE STARTED TO SEE CONVECTION FIRE OFF...PARTICULARLY
ACROSS WV/ERN KY/SW VA. MUCH OF THIS CONVECTION SHOULD DIE OFF AFTER
SUNSET...BUT WITH THE LIGHT FLOW...AND HUMID AIRMASS IN
PLACE...EXPECT LOCALIZED DOWNPOURS. 1 HOUR FFG AT THIS POINT IS
GENERALLY 1.6 INCHES OR GREATER...SO NOT TOO CONCERNED ABOUT WATER
ISSUES...BUT LOCALIZED ISSUES...PARTICULARLY IN LOW LYING
SPOTS...CANNOT BE RULED OUT. MAINLY FOLLOWED THE HRRR MODEL FOR
CONVECTION THIS AFTERNOON...AND INCREASED POPS FROM PREVIOUS
FORECAST.
MUCH OF THE ACTIVITY WILL WANE OVERNIGHT. COULD BE MORE FOG
FORMATION THAN CURRENTLY FORECAST FOR TONIGHT. THIS WILL DEPEND ON
HOW MUCH CLEARING IS ABLE TO OCCUR...AND LOCATIONS OF RAINFALL THIS
AFTERNOON. A WEAK UPPER DISTURBANCE IS EXPECTED TO MOVE NORTHEAST
THROUGH THE CWA TONIGHT AND ON FRIDAY...WHICH COULD HELP PROVIDE
ENOUGH CLOUD COVER TO KEEP MUCH OF THE FOG FORMATION AT BAY.
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE AGAIN ON FRIDAY
AS THE WEAK DISTURBANCE MOVES THROUGH THE REGION...COMBINED WITH
DAYTIME HEATING. COLD FRONT WILL BEGIN TO APPROACH THE AREA TOWARDS
THE END OF THE PERIOD...GENERALLY ACROSS NW OHIO/NORTHERN IN BY END
OF PERIOD. DUE TO THE TIMING OF THE FRONT...SEVERE IS NOT EXPECTED
ON FRIDAY...BUT HEAVY DOWNPOURS WILL CONTINUE TO BE POSSIBLE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
WE SEEM TO BE BOTTOM FEEDERS LATELY. LIFE AT THE BOTTOM OF THE
WESTERLIES CONTINUES DURING THIS TIME FRAME...WITH ANOTHER FRONT
TRYING TO SINK SOUTH SATURDAY...BUT THEN STRUGGLING TO MOVE SOUTH
OF OUR FORECAST AREA SATURDAY NIGHT INTO SUNDAY MORNING.
NO MAJOR CHANGES TO THE MAIN "BISCUIT" ON SATURDAY INTO SATURDAY
EVENING.
BACK TO FRIDAY NIGHT. STILL WANT TO KEEP MOST OF THE LOWLANDS DRY
FOR THE EVENING HOURS. HAD THE 20 AND 30 POPS FROM THE AFTERNOON
WANING OVER THE MOUNTAIN COUNTIES 00Z TO 03Z. HAVE CHANCE POPS
INCREASING 04Z TO 10Z SATURDAY IN SOUTHEAST OHIO...AHEAD OF THE NEXT
FRONT AND APPROACHING MID LEVEL DISTURBANCES IN THE BASE OF THE
WESTERLY FLOW IN THE MIDWEST.
STILL HAVE OUR LIKELY POPS MOVING SE ACROSS CWA DURING THE 12Z
SATURDAY TO 00Z SUNDAY TIME FRAME. COULD EASILY SEE BAND OF
CONVECTION WELL AHEAD OF THE FRONT...THEN A SMALLER BAND NEAR THE
FRONT LATER SATURDAY AFTERNOON INTO SATURDAY EVENING. COULD EASILY
SEE 2000+ J/KG CAPE DEVELOP ESPECIALLY CKB-HTS ON E AND SE BY
AFTERNOON. YET...STEERING WIND FLOW FROM 12Z MODELS ABOUT 25 TO 30
KNOTS...NOT TOO FAST...NOT TOO SLOW.
DID TRY TO INCREASE MAX TEMPERATURE A BIT FROM EKN-CRW ON SE ON
SATURDAY...FIGURING THE HIGHER POPS DO NOT ARRIVE UNTIL THE AFTERNOON
HOURS. ALSO TRIED TO HAVE THAT MAXIMUM TEMPERATURE AROUND MIDDAY
SATURDAY WITH TEMPERATURES MODIFIED BY CONVECTION DURING THE MID AND
LATE AFTERNOON.
THIS FRONT EXPECTED TO CREEP THROUGH...BUT LOW LEVEL WINDS AGAIN
VEER QUICKLY FROM NORTH TO EAST...RESULTING IN HOLDING UP THE DRYING
IN SOUTHERN WEST VIRGINIA AND SOUTHWEST VIRGINIA ON SUNDAY. MAIN
DRYING IN THE NORTH AND WESTERN COUNTIES. DIFFICULT TO FIGURE
WHEN...OR IF...THE CLOUDS IN THE SOUTH WILL BREAK SUNDAY AFTERNOON.
SO KEPT MAXIMUM TEMPERATURES DOWN ACROSS THE SOUTHERN WV COAL FIELDS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
USED WPC THINKING WITH SOME TWEAKS. WEAK SURFACE HIGH PRESSURE
WILL BE IN CONTROL ACROSS THE REGION SUNDAY NIGHT INTO MONDAY
NIGHT. A WARM FRONT WILL THEN LIFT NORTH TUESDAY...WITH A COLD
FRONT PUSHING EAST ON THURSDAY.
WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
18Z THURSDAY THRU 18Z FRIDAY...
SCATTERED CONVECTION THROUGH 00-02Z FRIDAY. EXPECT BRIEF MVFR
CONDITIONS IN VICINITY OF STORMS.
EXPECT PATCHY IFR FOG TO DEVELOP AGAIN TONIGHT...PARTICULARLY
AFTER 06Z...IN AREAS WHERE CLEARING IS ABLE TO TAKE PLACE...AND
WHERE PRECIPITATION OCCURS THURSDAY AFTERNOON. ANY FOG WILL LIFT
AFTER 13Z FOR A RETURN OF VFR CONDITIONS AREA WIDE.
CONVECTION WILL REFIRE ACROSS AREA...PARTICULARLY WV/SOUTHWEST
VA/ERN KY AGAIN AFTER 16Z FRIDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CONVECTION MAY VARY FROM FORECAST.
EXTENT AND DEPTH OF FOG FORMATION TONIGHT MAY VARY FROM FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
CRW CONSISTENCY H H H H H H H H H M M H
HTS CONSISTENCY H H H H H H H H H M M M
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H M M H
CKB CONSISTENCY H H H H H H H H H M M M
AFTER 18Z FRIDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SATURDAY. IFR FOG
POSSIBLE SUNDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/KTB/SL
NEAR TERM...ARJ/SL
SHORT TERM...KTB
LONG TERM...JSH
AVIATION...SL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
315 PM EDT THU SEP 4 2014
.SYNOPSIS...
WEAK HIGH PRESSURE SLIDES EAST WITH INCREASING MOISTURE THROUGH
FRIDAY. COLD FRONT MOVES ACROSS SATURDAY AFTERNOON. FRONT SLOWS
DOWN AS IT CREEPS SOUTH OF AREA. WEAK HIGH PRESSURE SUNDAY AFTERNOON.
&&
.NEAR TERM /THROUGH FRIDAY/...
HIGH PRESSURE...OFF TO THE EAST...HAS ALLOWED FOR WARM AND MUGGY
WEATHER ACROSS THE REGION...WITH DEW POINTS ACROSS MUCH OF THE AREA
THIS AFTERNOON IN THE MID 60S TO LOWER 70S. SATELLITE PW ESTIMATES
AROUND 1.2 TO 1.4 INCHES ACROSS MUCH OF SOUTHWEST VA...WEST VA...AND
EASTERN KY...WITH LOWER PWS OF AROUND AN INCH ACROSS SOUTHEAST OHIO.
WITH THE LIGHT SOUTHERLY FLOW...AND THE HUMID UNSTABLE AIRMASS IN
PLACE...HAVE STARTED TO SEE CONVECTION FIRE OFF...PARTICULARLY
ACROSS WV/ERN KY/SW VA. MUCH OF THIS CONVECTION SHOULD DIE OFF AFTER
SUNSET...BUT WITH THE LIGHT FLOW...AND HUMID AIRMASS IN
PLACE...EXPECT LOCALIZED DOWNPOURS. 1 HOUR FFG AT THIS POINT IS
GENERALLY 1.6 INCHES OR GREATER...SO NOT TOO CONCERNED ABOUT WATER
ISSUES...BUT LOCALIZED ISSUES...PARTICULARLY IN LOW LYING
SPOTS...CANNOT BE RULED OUT. MAINLY FOLLOWED THE HRRR MODEL FOR
CONVECTION THIS AFTERNOON...AND INCREASED POPS FROM PREVIOUS
FORECAST.
MUCH OF THE ACTIVITY WILL WANE OVERNIGHT. COULD BE MORE FOG
FORMATION THAN CURRENTLY FORECAST FOR TONIGHT. THIS WILL DEPEND ON
HOW MUCH CLEARING IS ABLE TO OCCUR...AND LOCATIONS OF RAINFALL THIS
AFTERNOON. A WEAK UPPER DISTURBANCE IS EXPECTED TO MOVE NORTHEAST
THROUGH THE CWA TONIGHT AND ON FRIDAY...WHICH COULD HELP PROVIDE
ENOUGH CLOUD COVER TO KEEP MUCH OF THE FOG FORMATION AT BAY.
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE AGAIN ON FRIDAY
AS THE WEAK DISTURBANCE MOVES THROUGH THE REGION...COMBINED WITH
DAYTIME HEATING. COLD FRONT WILL BEGIN TO APPROACH THE AREA TOWARDS
THE END OF THE PERIOD...GENERALLY ACROSS NW OHIO/NORTHERN IN BY END
OF PERIOD. DUE TO THE TIMING OF THE FRONT...SEVERE IS NOT EXPECTED
ON FRIDAY...BUT HEAVY DOWNPOURS WILL CONTINUE TO BE POSSIBLE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
WE SEEM TO BE BOTTOM FEEDERS LATELY. LIFE AT THE BOTTOM OF THE
WESTERLIES CONTINUES DURING THIS TIME FRAME...WITH ANOTHER FRONT
TRYING TO SINK SOUTH SATURDAY...BUT THEN STRUGGLING TO MOVE SOUTH
OF OUR FORECAST AREA SATURDAY NIGHT INTO SUNDAY MORNING.
NO MAJOR CHANGES TO THE MAIN "BISCUIT" ON SATURDAY INTO SATURDAY
EVENING.
BACK TO FRIDAY NIGHT. STILL WANT TO KEEP MOST OF THE LOWLANDS DRY
FOR THE EVENING HOURS. HAD THE 20 AND 30 POPS FROM THE AFTERNOON
WANING OVER THE MOUNTAIN COUNTIES 00Z TO 03Z. HAVE CHANCE POPS
INCREASING 04Z TO 10Z SATURDAY IN SOUTHEAST OHIO...AHEAD OF THE NEXT
FRONT AND APPROACHING MID LEVEL DISTURBANCES IN THE BASE OF THE
WESTERLY FLOW IN THE MIDWEST.
STILL HAVE OUR LIKELY POPS MOVING SE ACROSS CWA DURING THE 12Z
SATURDAY TO 00Z SUNDAY TIME FRAME. COULD EASILY SEE BAND OF
CONVECTION WELL AHEAD OF THE FRONT...THEN A SMALLER BAND NEAR THE
FRONT LATER SATURDAY AFTERNOON INTO SATURDAY EVENING. COULD EASILY
SEE 2000+ J/KG CAPE DEVELOP ESPECIALLY CKB-HTS ON E AND SE BY
AFTERNOON. YET...STEERING WIND FLOW FROM 12Z MODELS ABOUT 25 TO 30
KNOTS...NOT TOO FAST...NOT TOO SLOW.
DID TRY TO INCREASE MAX TEMPERATURE A BIT FROM EKN-CRW ON SE ON
SATURDAY...FIGURING THE HIGHER POPS DO NOT ARRIVE UNTIL THE AFTERNOON
HOURS. ALSO TRIED TO HAVE THAT MAXIMUM TEMPERATURE AROUND MIDDAY
SATURDAY WITH TEMPERATURES MODIFIED BY CONVECTION DURING THE MID AND
LATE AFTERNOON.
THIS FRONT EXPECTED TO CREEP THROUGH...BUT LOW LEVEL WINDS AGAIN
VEER QUICKLY FROM NORTH TO EAST...RESULTING IN HOLDING UP THE DRYING
IN SOUTHERN WEST VIRGINIA AND SOUTHWEST VIRGINIA ON SUNDAY. MAIN
DRYING IN THE NORTH AND WESTERN COUNTIES. DIFFICULT TO FIGURE
WHEN...OR IF...THE CLOUDS IN THE SOUTH WILL BREAK SUNDAY AFTERNOON.
SO KEPT MAXIMUM TEMPERATURES DOWN ACROSS THE SOUTHERN WV COAL FIELDS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
USED WPC THINKING WITH SOME TWEAKS. WEAK SURFACE HIGH PRESSURE
WILL BE IN CONTROL ACROSS THE REGION SUNDAY NIGHT INTO MONDAY
NIGHT. A WARM FRONT WILL THEN LIFT NORTH TUESDAY...WITH A COLD
FRONT PUSHING EAST ON THURSDAY.
WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
18Z THURSDAY THRU 18Z FRIDAY...
SCATTERED CONVECTION THROUGH 00-02Z FRIDAY. EXPECT BRIEF MVFR
CONDITIONS IN VICINITY OF STORMS.
EXPECT PATCHY IFR FOG TO DEVELOP AGAIN TONIGHT...PARTICULARLY
AFTER 06Z...IN AREAS WHERE CLEARING IS ABLE TO TAKE PLACE...AND
WHERE PRECIPITATION OCCURS THURSDAY AFTERNOON. ANY FOG WILL LIFT
AFTER 13Z FOR A RETURN OF VFR CONDITIONS AREA WIDE.
CONVECTION WILL REFIRE ACROSS AREA...PARTICULARLY WV/SOUTHWEST
VA/ERN KY AGAIN AFTER 16Z FRIDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CONVECTION MAY VARY FROM FORECAST.
EXTENT AND DEPTH OF FOG FORMATION TONIGHT MAY VARY FROM FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 18Z FRIDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SATURDAY. IFR FOG
POSSIBLE SUNDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/KTB/SL
NEAR TERM...SL
SHORT TERM...KTB
LONG TERM...JSH
AVIATION...SL
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
235 PM EDT THU SEP 4 2014
.SHORT TERM (TONIGHT AND FRIDAY)...
A MOIST AIR MASS AND MIDLEVEL SHEAR ZONE BETWEEN TWO RIDGES WILL
REMAIN OVER THE REGION THROUGH FRIDAY. WITH LITTLE PATTERN
CHANGE...WILL FOLLOW MAINLY A PERSISTENCE FORECAST. THE NAM SEEMS TO
BE PERFORMING PRETTY WELL WITH THE PATTERN...AND THE HRRR HAS BEEN
RELIABLE IN DEPICTING AREAS OF AND TIMING OF CONVECTION. IT SHOWS
ONGOING PRECIP LINGERING IN NE SECTIONS UNTIL DISSIPATING AROUND
MIDNIGHT...AND WILL FOLLOW THAT SOLUTION FOR TONIGHT. AS WE SAW THIS
MORNING...PATCHY FOG AND LOW CLOUDS CAN BE EXPECTED TO START THE DAY
IN MOST SPOTS. THE ONE DIFFERENCE IN THE NAM TOMORROW APPEARS TO BE
THAT THE 700 MB DEFORMATION/SHEAR ZONE SHIFTS SLIGHTLY TO THE SOUTH
AND EAST...WHICH MAY LEAD TO SOUTHERN AND EASTERN AREAS BEING A BIT
MORE FAVORED FOR AFTERNOON CONVECTION THAN NORTHERN AND WESTERN
AREAS. STILL...WILL HAVE CHANCE POPS EVERYWHERE TOMORROW AFTERNOON.
GFS MOS HIGH TEMPS APPEAR TOO WARM TOMORROW...AND HAVE VERIFIED TOO
WARM THE PAST FEW DAYS...SO WILL UNDERCUT THEM BY SEVERAL DEGREES.
.LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)...
A COLD FRONT WILL MOVE THROUGH THE AREA SATURDAY EVENING...WITH
SHOWERS AND THUNDERSTORMS DEVELOPING THROUGH THE DAY SATURDAY AHEAD
OF THIS FRONT. INSTABILITY AND SHEAR ARE UNIMPRESSIVE...SO LOOKING
AT MAIN THREAT OF HEAVY RAIN WITH THESE STORMS. NEAR ZONAL FLOW WIL
SET UP OVER THE AREA BEHIND THIS FRONT. THE AIRMASS DOES NOT YEILD
MUCH CHANGE IN THE WAY OF COOLER TEMPERATURES SUNDAY THROUGH THE
END OF THE PERIOD. BUT DOES HAVE DRIER AIR ADVECTED IN THE
MIDLEVELS. THIS ALONG WITH THE AFTERNOON HEATING...EXPECTING TO SEE
DIURNAL THUNDERSTORMS EACH DAY. UPPER LEVEL MOISTURE WILL CONTINUE
TO INCREASE THROUGH THIS PERIOD...SO WILL ONLY SEE PARTLY CLOUDY
SKIES FOR A DAY OR TWO AT THE BEGINNING OF THE WORK WEEK. THE NEXT
BIG FEATURE MOVING INTO THE AREA IS ANOTHER COLD FRONT SET TO MOVE
IN TOWARDS THE END OF NEXT WEEK. MODELS DIFFER ON TIMING AND
STRENGTH OF THIS SYSTEM...SO SETTLED FOR CHANCE POPS THURSDAY AND
FRIDAY. TEMPERATURES WILL BE A COUPLE OF DEGREES ABOVE NORMAL FOR
THIS TIME OF YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 70 89 69 87 / 20 50 20 50
KNOXVILLE MCGHEE TYSON AIRPORT, TN 69 87 68 86 / 20 40 20 60
OAK RIDGE, TN 68 87 68 86 / 20 40 20 60
TRI CITIES AIRPORT, TN 66 87 64 86 / 40 40 20 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS/JW
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1243 PM CDT THU SEP 4 2014
.AVIATION 18Z DISCUSSION...
A WEAK N-S MID/UPPER LEVEL TROUGH RESIDES ACROSS THE MID STATE
THIS AFTERNOON. LOW LEVEL FETCH OF ADDED HUMIDITY WILL CONTINUE TO
ALLOW FOR CONVECTIVE PARAMETERS TO BE MORE FAVORABLE...PARTICULARLY
ACROSS EASTERN AREAS OF MIDDLE TN. AS A RESULT...A FEW SHOWERS AND
TSTMS WILL BE POSSIBLE THIS AFTERNOON NEAR CSV. CURRENT TOVER
VALUES ARE RUNNING SLIGHTLY NEGATIVE. WILL THEREFORE INCLUDE SOME
LATE NIGHT FOG. TOMORROW...AROUND 18Z...CONVECTION MAY REFIRE NEAR
CSV. WILL LEAVE THE MENTION OF CONVECTION OUT FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 932 AM CDT THU SEP 4 2014/
MORNING DISCUSSION UPDATE...
LATEST STREAMLINE ANALYSIS CONTINUES TO SHOW A HUMID FLOW PATTERN
IN THE LOWER LEVELS. NOT MUCH TO SPEAK OF AS FAR AS LOW LEVEL
DYNAMICS. BUT...THE MID AND UPPER LEVEL PATTERN SHOWS WEAK N-S
TROUGHING EXTENDING FROM THE NORTHERN GULF NORTHWARD ACROSS THE
MID STATE. MRH PROFILES SHOW A DEFINITIVE MOIST TO DRY GRADIENT
FROM EAST TO WEST. THIS WILL ALLOW CONVECTIVE PARAMETERS TO BE A
LITTLE MORE FAVORABLE ACROSS OUR EASTERN COUNTIES FOR TODAY.
LATEST HRRR IS IN LINE WITH THE CURRENT FCST AND SHOWS CONVECTION
DEVELOPING ACROSS OUR EASTERN COUNTIES AROUND OR SHORTLY BEFORE
NOON. QPF AVERAGES ACROSS THE EAST SHOULD BE ON THE LIGHT SIDE.
CAPES DON`T LOOK IMPRESSIVE ENOUGH TODAY TO SUPPORT ANY STRONG
ACTIVITY.
AS FOR TEMPERATURES...LATEST NUMERICAL GUIDANCE AND EXPECTED TEMPS
AT 15Z LOOK TO BE IN LINE WITH EXPECTED HIGHS.
NO UPDATED NEEDED FOR NOW OTHER THAN TO REISSUE AND REMOVE THE
MENTION OF FOG. STILL 3SM BR AT CKV BUT THIS SHOULD CONTINUE TO
IMPROVE. OTW...IF THE ONSET OF CONVECTION IS FURTHER WEST THAN
EXPECTED...WILL EXPAND THE WEATHER GRIDS A LITTLE FURTHER WESTWARD
IF NEEDED.
PREV DISCUSSION... /ISSUED 628 AM CDT THU SEP 4 2014/
UPDATE...FOR AVIATION.
AVIATION...
12Z TAFS...LOOKING FOR MAINLY VFR TODAY. DENSE FOG CURRENTLY AT
CKV WILL LIFT BY 14Z. SCT TSRA OVER THE PLATEAU THIS
AFTERNOON...SO INCLUDING VCTS FOR CSV. OTHERWISE...SCT CUMULUS
CLOUDS TODAY WITH S WINDS NEAR 6KT. PATCHY FOG EXPECTED
TONIGHT...MAINLY MVFR...BUT CKV COULD GO DOWN TO LIFR AGAIN.
13
PREV DISCUSSION... /ISSUED 308 AM CDT THU SEP 4 2014/
DISCUSSION...
FORECAST QUANDARIES...POTENTIAL FOR PATCHY DENSE FOG FORMATION
THIS MORNING... SHWR/TSTMS CHANCES...ANY MODEL TIMING DIFFERENCES
IN OVERALL WX PATTERN THIS WEEKEND...TEMPS.
AS THRU THE MID MORNING HRS FOR TODAY...WILL BE MONITORING THIS MORNING
PATCHY FOG FORMATION THRU AND AROUND PRESS TIME...WITH VSBYS ALREADY
BELOW ONE MILE IN SOME SELECTED LOCATIONS ACROSS SRN PORTIONS OF MID
STATE. THREE SCENARIOS COULD PLAY OUT...JUST MENTIONING PATCHY FOG THRU
THE MID MORNING HRS IN THE SUITE OF FORECAST PRODUCTS...POSSIBLE ISSUANCE
OF AN SPS DEALING WITH LOCALLY DENSE FOG FORMATION THRU MID MORNING
HRS...OR A DENSE FOG ADVISORY FOR A PORTIONS/ALL OF MID STATE. NO MATTER
WHAT...DEWPOINT DEPRESSIONS...CALM WINDS...AND CLRING SKIES ARE ALL
FAVORABLE THRU THE MID MORNING HRS FOR FOG FORMATION. KEY TO MORE WIDESPREAD
PATCHY TO DENSE FOG DEVELOPMENT ACROSS PLATEAU REGION WILL BE IF THERE
IS ANY BREAKS/EROSION OF CLOUD COVERAGE PRESENTLY ACROSS PLATEAU COUNTIES...
WHERE SHORT RANGE MODEL CONSENSUS ALONG WITH CURRENT SATELLITE TRENDS
SHOWING CURRENT CLOUD COVERAGE TRENDS AT LEAST GENERALLY MAINTAIN ITSELF
THRU THE MID MORNING HOURS. WILL BE WATCHING THIS CAREFULLY ON WHAT
DECISION TO DO CONCERNING FOG FORMATION OVER THIS PORTION OF THE MID
STATE. WHATEVER DECISION IS FINALLY MADE HERE...WILL ALSO HIGHLIGHT
IT IN THE MORNING`S HAZARDOUS WEATHER OUTLOOK.
AS FOR THE MID MORNING HRS TODAY THRU FRI NIGHT...MODEL CONSENSUS CONTINUES
TO SHOW RIDGING INFLUENCES SFC/ALOFT ALONG WITH A CONTINUANCE OF PLENTIFUL
LOW LEVEL MOISTURE INTERACTING WITH DIURNAL INFLUENCES AND LOCAL OROGRAPHIC
EFFECTS...RESULTING IN A TYPICAL SUMMERTIME PATTERN FOR THE MID STATE
THRU FRI WITH MAINLY LATE MORNING THRU EARLY EVENING SHWRS/TSTMS...WITH
THE BEST CHANCE OF SHWRS/TSTMS ACROSS ERN PORTIONS INCLUDING PLATEAU
REGION WHERE BEST OVERALL MOISTURE WILL CONTINUE TO BE USHERED INTO
MID STATE AREA PER THIS MOISTURE BEING ON PERIPHERY OF SFC BERMUDA
HIGH PRESSURE INFLUENCES. WILL ALSO CONTINUE LEANING TOWARD THE WARMER
GFS MOS SOLUTION ON HIGHS WITH THIS SUMMER TIME PATTERN...LOWER 90S...
MID TO UPPER 80S PLATEAU WITH LOWS AROUND 70...UPPER 60S PLATEAU. WILL
KEEP A SLIGHT CHANCE TO CHANCE OF SHWRS/TSTMS THRU FRI NIGHT AS MOISTURE
POOLS AND SHORTWAVE APPROACHES.
AS FOR THE WEEKEND INTO THE FIRST PART OF NEXT WEEK...STILL LOOKS LIKE
ANOTHER RATHER WEAK SFC FRONT IS EXPECTED TO PASS THRU THE MID STATE
AS SAT PROGRESSES WITH ANOTHER SHORTWAVE PASSAGE RESULTING IN SCT SHWRS/TSTMS
ACROSS THE MID STATE FROM AT LEAST THE LATE MORNING HRS THRU POSSIBLY
THE ENTIRE EVENING HRS. A GOOD MODEL CONSENSUS HAS BEEN REACHED WITH
THESE FEATURES NOW. ALSO...FROM TODAY THRU SAT...WOULD NOT BE SURPRISED
FOR A FEW TSTMS TO AT LEAST REACH STRONG THRESHOLDS...AND WILL MENTION
THIS IN THE MORNING HAZARDOUS WEATHER OUTLOOK ISSUANCE ALSO. MID-UPPER
MS RIVER VALLEY 1020MB SFC HIGH PRESSURE PATTERN WILL BEGIN INFLUENCING
THE MID STATE`S WEATHER BY SUN RESULTING IN A TREND BACK TOWARD TEMPS
BEING MORE AROUND SEASONABLE NORMAL VALUES. LATEST GFS MOS GUIDANCE
COMING MORE IN LINE WITH PREVIOUS RUNS OF THE EURO SOLUTION WITH TEMPS
NEAR SEASONABLE NORMAL VALUES THRU THE MID PORTION OF NEXT WEEK. WILL
CONTINUE WITH A SLIGHT CHANCE OF DIURNALLY DRIVEN SHWRS/TSTMS SUN INTO
MON AS QUASI ZONAL FLOW ALOFT AIDING IN PASSAGES OF ADDITIONAL SHORTWAVES
IN FLOW ALOFT. THERE ARE SOME TIMING DIFFERENCES BETWEEN THE LATEST
GFS/DGEX AND EURO IN WHEN POTENTIALLY MORE SIGNIFICANT SHORTWAVE PASSAGE
IS EXPECTED THRU THE MID PORTION OF NEXT WEEK...BUT WILL CONTINUE WITH
A GENERALLY TREND OF TREND TOWARD SCT SHWRS/TSTMS THRU WED AS SFC PATTERN
BECOMES MORE SLY ORIENTATED IN NATURE USHERING IN ADDITIONAL MOISTURE
TO MID STATE.
31
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 PM CDT THU SEP 4 2014
.MESOSCALE DISCUSSION...
ISSUED AT 530 PM CDT THU SEP 4 2014
WATCHING SUPERCELL CLOSELY TRACKING EAST THROUGH CENTRAL
TREMPEALEAU COUNTY. ITS ON THE NOSE OF 4000 MLCAPE PER SPC
MESOANALYSIS PAGE...AND 0-1KM SHEAR IS 25-30 KT. APPEARS RIGHT NOW
THE STORM IS NOT SURFACE BASED AS 0.5 DEGREE SRM DOES NOT SHOW
MUCH ROTATION. HOWEVER...IF THAT ROTATION INCREASES...THE
POTENTIAL WOULD EXIST FOR THE SUPERCELL TO DROP A TORNADO.
OTHERWISE...LOOKING AHEAD INTO THE EVENING...04.20Z HRRR IS QUITE
AGGRESSIVE IN DEVELOPING CONVECTION IN THE 7-9 PM WINDOW...WITH
POTENTIAL SEVERE STORMS IN CENTRAL WISCONSIN. WILL KEEP A CLOSE
EYE ON THIS POTENTIAL AS WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS.
LATEST SURFACE ANALYSIS PLACED LOW PRESSURE OVER CENTRAL
MINNESOTA...EDGING EAST. A COLD FRONT EXTENDED SOUTHWARD INTO WESTERN
IOWA WHILE A WARM FRONT WAS POSITIONED NEAR THE INTERSTATE 94
CORRIDOR IN EAST CENTRAL MINNESOTA THROUGH WESTERN WISCONSIN.
EXTENSIVE CLOUD COVER OVER MUCH OF THE FORECAST AREA WAS HELPING TO
HOLD TEMPERATURES DOWN A BIT. SHOWERS AND STORMS ARE DEVELOPING
ACROSS AREAS NORTH OF INTERSTATE 90 DESPITE A FAIRLY STOUT CAP IN
PLACE. FORECAST SOUNDINGS ARE INDICATING 750 MB TEMPERATURES
HOVERING RIGHT AROUND 15 C. SOUNDINGS SUGGEST THIS CAP WILL WEAKEN
AS A SHORTWAVE APPROACHES FROM NEBRASKA/SOUTH DAKOTA THIS AFTERNOON
INTO THIS EVENING JUST AS THE COLD FRONT IS MAKING ITS WAY INTO
NORTHWESTERN SECTIONS OF THE FORECAST AREA. MESOSCALE MODELS ARE
FIRING SHOWERS AND STORMS ALONG AND BEHIND THE FRONT THIS EVENING.
IF THIS SCENARIO PLAYS OUT...THE MAIN THREATS FROM THE STORMS WOULD
BE LARGE HAIL AND HEAVY RAINFALL. WE SHOULD SEE A BAND OF SHOWERS
AND STORMS DEVELOP RIGHT OVER THE FORECAST AREA THIS EVENING THEN
THIS BAND WILL GRADUALLY PUSH SOUTHEAST DURING THE OVERNIGHT HOURS
AS THE FRONT SAGS SOUTHWARD. MUCH COOLER AIR PUSHES INTO THE
FORECAST AREA IN THE WAKE OF THE FRONT TONIGHT INTO FRIDAY WITH 850
MB TEMPS GOING FROM 25 C THIS AFTERNOON TO AROUND 10 C BY FRIDAY
AFTERNOON. A VERY COMFORTABLE DAY IS IN STORE FOR THE REGION ON
FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. PLAN PARTLY SUNNY
SKIES ACROSS THE REGION WITH HIGHS RANGING FROM THE MID 60 TO LOWER
70S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
HIGH PRESSURE REMAINS IN CONTROL FRIDAY NIGHT INTO SUNDAY AS THE
REGION REMAINS IN A COOL NORTHWEST FLOW REGIME. WITH THE RIDGE AXIS
NEARBY PROVIDING LIGHT AND VARIABLE WINDS FROM THE SURFACE THROUGH 2
KFT MAY SET THE STAGE FOR AREAS OF FOG LATE SATURDAY NIGHT INTO
SUNDAY MORNING. HAVE INCLUDED PATCHY FOG ALONG RIVER VALLEY
LOCATIONS AND OVER CENTRAL WISCONSIN DURING THIS TIMEFRAME. THE NEXT
CHANCE FOR SHOWERS AND STORMS ACROSS THE REGION ARRIVES ON MONDAY AS
FLOW ALOFT TURNS MORE ZONAL AND A SHORTWAVE TROUGH MOVES IN FROM THE
PLAINS. TEMPERATURES WILL REMAIN SEASONABLY COOL THROUGH THE PERIOD
WITH HIGHS MAINLY IN THE 70S. A MORE UNSETTLED PATTERN IS EXPECTED
TO DEVELOP NEXT WEEK AND WILL REMAIN OVER THE REGION THROUGH
THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1230 PM CDT THU SEP 4 2014
STRONG CAP IN THE 800-700 MB LAYER WORKS ACROSS THE AREA THIS
AFTERNOON INTO THE EVENING...AND LOOKS TO BE A STRONG ENOUGH
INHIBITOR TO PREVENT CONVECTION. SOME MVFR CIGS CURRENTLY ASSOCIATED
POST AN OUTFLOW BOUNDARY SINKING SOUTH ACROSS KRST/KLSE...MORE AMPLE
COVERAGE NEAR KLSE. WITH THE INVERSION EXPECTED TO HOLD THROUGH THE
AFTERNOON...THE MVFR CLOUDS COULD FOLLOW SUIT. WILL HOLD SOME MVFR
CIGS THROUGH AT LEAST MID AFTERNOON - BUT COULD BE NEEDED LONGER.
MESO MODELS PROVIDING A VARIETY OF SOLUTIONS ON WHERE/WHEN
CONVECTION COULD REFIRE THIS AFTERNOON AND EVENING. CONFIDENCE LOWER
AS A RESULT. THAT SAID...GOING TO PUT FAITH IN THE STRONG LOW LEVEL
WARMING/CAP WHICH WILL NEED AN APPROACHING COLD FRONT TO THE WEST TO
PROVIDE A SHOWER/STORM THREAT. SOMEWHERE IN THE 02-04Z TIME FRAME
LOOKS TO BE THE MOST FAVORABLE TIME FOR PRECIPITATION.
ANTICIPATE CHANGES TO THE FORECAST AS THE CONVECTIVE TIMING/COVERAGE
BECOMES CLEARER.
CLOUDS LIKELY TO HANG AROUND POST FRONT THROUGH FRI MORNING...BUT
APPEAR TO BE THE MID/UPPER LEVEL VARIETY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
210 PM CDT THU SEP 4 2014
.UPDATED...
ISSUED AT 210 PM CDT THU SEP 4 2014
SHOWERS/STORMS QUICKLY DEVELOPING ACROSS PARTS OF THE
REGION...MOSTLY NORTH OF I-90. DESPITE A STRONG 800-700 MB CAP WITH
16-18 C TEMPS...PREVIOUS OUTFLOW BOUNDARY/WARM FRONT MIX...COUPLED
WITH PUSH OF SLOPING LOW LEVEL MOISTURE TRANSPORT INTO ELEVATED
INSTABILITY...HAS KICKED OFF THE CONVECTION. RAP13 SUGGESTS THIS
ACTIVITY WILL CONTINUE TO EXPAND AND PUSH EASTWARD FOR THE REST OF
THE AFTERNOON. THERE COULD BE A FEW STRONGER STORMS...ALTHOUGH
SEVERE WEATHER IS NOT ANTICIPATED AT THIS TIME.
THERE STILL APPEARS TO BE A THREAT FOR STRONG-SEVERE STORMS AROUND
MID EVENING...AS A COLD FRONT WORKS IN FROM THE WEST. MOST OF THIS
ACTIVITY APPEARS TO BE POST FRONTAL...BUT WILL STILL HAVE DECENT
INSTABILITY AND SOME WIND SHEAR TO TAP INTO.
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 326 AM CDT THU SEP 4 2014
SURFACE MAP AS OF 3 AM THIS MORNING HAD A DEEP 996MB LOW OVER
EASTERN SD WITH A WARM FRONT EXTENDING ACROSS SOUTHERN MN AND INTO
SOUTHWEST WI. CURRENTLY WATCHING ONE CLUSTER OF STRONG THUNDERSTORMS
DEPARTING THE AREA INTO NORTHEAST WI. WITHIN THE LAST 1/2 HOUR...A
CLUSTER OF SHOWERS AND THUNDERSTORMS POPPED UP OVER FAR NORTHEAST
IA/SOUTHWEST WI. FURTHER ANALYSIS SHOWING THESE SHOWERS AND STORMS
FORMING IN RESPONSE TO A NOSE OF STRONG 850MB MOISTURE TRANSPORT
WORKING NORTHEAST ACROSS IA...AND OCCURRING ABOVE A VERY STRONG 700-
750MB CAP OF 14C PER THE RAP BUFKIT AT BLUE RIVER WI. OTHERWISE...
TEMPERATURES ACROSS THE AREA EARLY THIS MORNING WERE IN THE 60S
ACROSS NORTH CENTRAL WI...AND IN THE 70S ELSEWHERE ACROSS THE ARX
FORECAST AREA.
WARM FRONT MAKES A PUSH NORTHEAST THROUGH THE REST OF THE AREA THIS
MORNING. THINKING THOSE SHOWERS/STORMS WILL SHOVE OUT OF THE AREA AS
CAP STRENGTHENS IN WARM SECTOR. WILL BE WATCHING AN MCS OVER ND
MAKING ITS WAY EAST-SOUTHEAST...WHICH COULD CLIP CLARK AND TAYLOR
COUNTIES AS IT MAKES ITS WAY ACROSS FAR NORTHERN WI/UPPER MI. MAY
HAVE TO ADJUST POPS ACCORDINGLY.
OTHERWISE...STRONG WARM AIR ADVECTION WILL TAKE PLACE ACROSS THE
AREA WITH STRENGTHENING 700-750MB CAP. THIS SHOULD HOLD OFF ANY
FURTHER CONVECTION AND PUSH TEMPERATURES WELL INTO THE 80S...TO A
FEW LOWER 90S ALONG/SOUTH OF I-90. DEW POINTS WILL ALSO BE
INCREASING INTO THE LOWER 70S THROUGH THE DAY...PRODUCING VERY
WARM/MUGGY/UNCOMFORTABLE CONDITIONS. HEAT INDICES FOR THE MOST PART
LOOK TO BE IN THE 90-100 RANGE...BUT COULD SEE A FEW HOURS OF 100-
105 IN A FEW SPOTS IN THE MISSISSIPPI/WISCONSIN RIVER VALLEYS. NOT
THINKING A HEAT ADVISORY WILL BE NEEDED AT THIS POINT DUE TO THE
BRIEF TOUCH IN THE CRITERIA RANGE. WILL HIT IT HARD WITH OUR OTHER
PRODUCTS.
CAP HOLDS STRONG INTO THE AFTERNOON HOURS AS A COLD FRONT PUSHES
SOUTHEASTWARD INTO NORTHERN WI/SOUTH CENTRAL MN. MODELS AT ODDS AT
HANDLING CONVECTION OR LACK THEREOF WHICH HEDGES ON STRENGTH OF
CAP...WHICH IS VERY STRONG FOR THIS TIME OF YEAR. GFS/ECMWF/CANADIAN
DETERMINISTIC MODELS ALL HOLD OFF DEVELOPING CONVECTION THROUGH 7PM.
NAM IS A BIT MORE GUNG-HO FIRING ALONG THE FRONT BASICALLY NORTH OF
I-94 BETWEEN 4-7PM. NMM/ARW WRF MODELS SIDE WITH THE NAM. REASON
BEING... BUFKIT SOUNDINGS REVEAL POSSIBLY SOME ELEVATED CONVECTION
BURBLING ABOVE THE CAP AS MID-LEVEL COOLING/STEEPENING LAPSE RATES
TAKE PLACE WITH INCOMING MID-LEVEL TROUGH. THIS WOULD COMPROMISE THE
CAP AND LET SURFACE BASED/DEEP CONVECTION RELEASE ALONG THE FRONT.
WILL HAVE TO KEEP AN EYE ON THIS FOR SEVERE WIND/HAIL POTENTIAL AS 0-
3KM BULK SHEAR IS PLENTIFUL IN THE 30-40KT RANGE ALONG WITH MUCAPE
IN THE 3000-4000J/KG RANGE.
THE COLD FRONT CONTINUES TO PUSH SOUTHEAST THROUGH THE AREA FRIDAY
NIGHT FOR CONTINUED THUNDERSTORM CHANCES. SOME OF THESE STORMS COULD
BE REMAIN SEVERE AT LEAST INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU SEP 4 2014
WITH THE COLD FRONT PUSHED INTO NORTHERN IL BY FRIDAY MORNING...
NORTHWEST WINDS WILL DRAW DRIER/COOLER AIR OVER THE FORECAST AREA.
EXPECTING FAIRLY BREEZY NORTHWEST WINDS IN THE 15-25MPH RANGE WITH
HIGHS ONLY TOPPING OFF IN THE UPPER 60S TO TO LOWER 70S.
MORE EARLY FALL-LIKE CONDITIONS ARE THEN EXPECTED INTO THE WEEKEND
AS CANADIAN HIGH PRESSURE DOMINATES THE CENTRAL CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. LOOK FOR MOSTLY CLEAR SKIES
THROUGH SUNDAY WITH HIGHS SATURDAY AND SUNDAY IN THE 70S AND
OVERNIGHT LOWS IN THE 40S TO LOWER 50S.
FOR MONDAY THROUGH WEDNESDAY...DEEPENING CYCLONIC FLOW OVER CANADA
AND NORTHERN CONUS WILL DRIVE A COUPLE TROUGHS THROUGH THE REGION FOR
A PERIOD OF UNSETTLED WEATHER WITH ON/OFF SHOWER AND THUNDERSTORM
CHANCES. TEMPERATURES ARE EXPECTED TO BE AT OR A FEW DEGREES BELOW
NORMAL WITH HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1230 PM CDT THU SEP 4 2014
STRONG CAP IN THE 800-700 MB LAYER WORKS ACROSS THE AREA THIS
AFTERNOON INTO THE EVENING...AND LOOKS TO BE A STRONG ENOUGH
INHIBITOR TO PREVENT CONVECTION. SOME MVFR CIGS CURRENTLY ASSOCIATED
POST AN OUTFLOW BOUNDARY SINKING SOUTH ACROSS KRST/KLSE...MORE AMPLE
COVERAGE NEAR KLSE. WITH THE INVERSION EXPECTED TO HOLD THROUGH THE
AFTERNOON...THE MVFR CLOUDS COULD FOLLOW SUIT. WILL HOLD SOME MVFR
CIGS THROUGH AT LEAST MID AFTERNOON - BUT COULD BE NEEDED LONGER.
MESO MODELS PROVIDING A VARIETY OF SOLUTIONS ON WHERE/WHEN
CONVECTION COULD REFIRE THIS AFTERNOON AND EVENING. CONFIDENCE LOWER
AS A RESULT. THAT SAID...GOING TO PUT FAITH IN THE STRONG LOW LEVEL
WARMING/CAP WHICH WILL NEED AN APPROACHING COLD FRONT TO THE WEST TO
PROVIDE A SHOWER/STORM THREAT. SOMEWHERE IN THE 02-04Z TIME FRAME
LOOKS TO BE THE MOST FAVORABLE TIME FOR PRECIPITATION.
ANTICIPATE CHANGES TO THE FORECAST AS THE CONVECTIVE TIMING/COVERAGE
BECOMES CLEARER.
CLOUDS LIKELY TO HANG AROUND POST FRONT THROUGH FRI MORNING...BUT
APPEAR TO BE THE MID/UPPER LEVEL VARIETY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATED.....RIECK
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1230 PM CDT THU SEP 4 2014
.UPDATED...
ISSUED AT 1230 PM CDT THU SEP 4 2014
STRONG LOW LEVEL CAP PROGGED TO BUILD ACROSS THE FORECAST AREA THIS
AFTERNOON...WITH 800-700 MB RAP LAYER TEMPS OF 16-18 C. MULTIPLE
OUTFLOW BOUNDARIES TO WATCH THROUGH THE AFTERNOON THOUGH...ONE OF
WHICH IS PROVIDING MORE LOW CLOUDS ACROSS WESTERN WI THEN PREVIOUSLY
THOUGHT. WITH STRONG INVERSION...THESE COULD STICK AROUND THROUGH
THE AFTERNOON. MEANWHILE A BOUNDARY ACROSS IA/NORTHERN IL HAS FIRED
SHOWERS/STORMS LATE IN THE MORNING...WITH THE MESO MODELS KEEPING
THIS ACTIVITY JUST SOUTH OF THE FORECAST AREA. FURTHER
NORTH...SCATTERED SHOWERS AND A FEW THUNDERSTORMS SHOULD CONTINUE TO
SPARK ACROSS AN OUTFLOW/WARM FRONTAL BOUNDARY...CURRENTLY LAYING UP
FROM CENTRAL MN INTO NORTHERN WI. TRENDS HERE FAVOR KEEPING THE BULK
OF ANY PCPN THREAT NORTH OF HIGHWAY 10 IN NORTHCENTRAL WI.
OVERALL...THE SCENARIO FAVORS DRY CONDITIONS THROUGH THE BETTER PART
OF THE AFTERNOON.
AS THE FRONT APPROACHES FROM WEST THIS EVENING...THE THREAT WILL
INCREASE WITH SHOWER/STORMS DEVELOPING-CONTINUING ABOVE THE
CAP...MOSTLY POST FRONTAL. THIS WOULD PLACE OUR HIGHER THREAT FOR
STORMS IN THE MID EVENING HOURS. THERE WOULD BE A STRONG-SEVERE
THREAT WITH THE STORMS...ALTHOUGH THAT APPEARS MORE ISOLATED IN
NATURE.
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 326 AM CDT THU SEP 4 2014
SURFACE MAP AS OF 3 AM THIS MORNING HAD A DEEP 996MB LOW OVER
EASTERN SD WITH A WARM FRONT EXTENDING ACROSS SOUTHERN MN AND INTO
SOUTHWEST WI. CURRENTLY WATCHING ONE CLUSTER OF STRONG THUNDERSTORMS
DEPARTING THE AREA INTO NORTHEAST WI. WITHIN THE LAST 1/2 HOUR...A
CLUSTER OF SHOWERS AND THUNDERSTORMS POPPED UP OVER FAR NORTHEAST
IA/SOUTHWEST WI. FURTHER ANALYSIS SHOWING THESE SHOWERS AND STORMS
FORMING IN RESPONSE TO A NOSE OF STRONG 850MB MOISTURE TRANSPORT
WORKING NORTHEAST ACROSS IA...AND OCCURRING ABOVE A VERY STRONG 700-
750MB CAP OF 14C PER THE RAP BUFKIT AT BLUE RIVER WI. OTHERWISE...
TEMPERATURES ACROSS THE AREA EARLY THIS MORNING WERE IN THE 60S
ACROSS NORTH CENTRAL WI...AND IN THE 70S ELSEWHERE ACROSS THE ARX
FORECAST AREA.
WARM FRONT MAKES A PUSH NORTHEAST THROUGH THE REST OF THE AREA THIS
MORNING. THINKING THOSE SHOWERS/STORMS WILL SHOVE OUT OF THE AREA AS
CAP STRENGTHENS IN WARM SECTOR. WILL BE WATCHING AN MCS OVER ND
MAKING ITS WAY EAST-SOUTHEAST...WHICH COULD CLIP CLARK AND TAYLOR
COUNTIES AS IT MAKES ITS WAY ACROSS FAR NORTHERN WI/UPPER MI. MAY
HAVE TO ADJUST POPS ACCORDINGLY.
OTHERWISE...STRONG WARM AIR ADVECTION WILL TAKE PLACE ACROSS THE
AREA WITH STRENGTHENING 700-750MB CAP. THIS SHOULD HOLD OFF ANY
FURTHER CONVECTION AND PUSH TEMPERATURES WELL INTO THE 80S...TO A
FEW LOWER 90S ALONG/SOUTH OF I-90. DEW POINTS WILL ALSO BE
INCREASING INTO THE LOWER 70S THROUGH THE DAY...PRODUCING VERY
WARM/MUGGY/UNCOMFORTABLE CONDITIONS. HEAT INDICES FOR THE MOST PART
LOOK TO BE IN THE 90-100 RANGE...BUT COULD SEE A FEW HOURS OF 100-
105 IN A FEW SPOTS IN THE MISSISSIPPI/WISCONSIN RIVER VALLEYS. NOT
THINKING A HEAT ADVISORY WILL BE NEEDED AT THIS POINT DUE TO THE
BRIEF TOUCH IN THE CRITERIA RANGE. WILL HIT IT HARD WITH OUR OTHER
PRODUCTS.
CAP HOLDS STRONG INTO THE AFTERNOON HOURS AS A COLD FRONT PUSHES
SOUTHEASTWARD INTO NORTHERN WI/SOUTH CENTRAL MN. MODELS AT ODDS AT
HANDLING CONVECTION OR LACK THEREOF WHICH HEDGES ON STRENGTH OF
CAP...WHICH IS VERY STRONG FOR THIS TIME OF YEAR. GFS/ECMWF/CANADIAN
DETERMINISTIC MODELS ALL HOLD OFF DEVELOPING CONVECTION THROUGH 7PM.
NAM IS A BIT MORE GUNG-HO FIRING ALONG THE FRONT BASICALLY NORTH OF
I-94 BETWEEN 4-7PM. NMM/ARW WRF MODELS SIDE WITH THE NAM. REASON
BEING... BUFKIT SOUNDINGS REVEAL POSSIBLY SOME ELEVATED CONVECTION
BURBLING ABOVE THE CAP AS MID-LEVEL COOLING/STEEPENING LAPSE RATES
TAKE PLACE WITH INCOMING MID-LEVEL TROUGH. THIS WOULD COMPROMISE THE
CAP AND LET SURFACE BASED/DEEP CONVECTION RELEASE ALONG THE FRONT.
WILL HAVE TO KEEP AN EYE ON THIS FOR SEVERE WIND/HAIL POTENTIAL AS 0-
3KM BULK SHEAR IS PLENTIFUL IN THE 30-40KT RANGE ALONG WITH MUCAPE
IN THE 3000-4000J/KG RANGE.
THE COLD FRONT CONTINUES TO PUSH SOUTHEAST THROUGH THE AREA FRIDAY
NIGHT FOR CONTINUED THUNDERSTORM CHANCES. SOME OF THESE STORMS COULD
BE REMAIN SEVERE AT LEAST INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU SEP 4 2014
WITH THE COLD FRONT PUSHED INTO NORTHERN IL BY FRIDAY MORNING...
NORTHWEST WINDS WILL DRAW DRIER/COOLER AIR OVER THE FORECAST AREA.
EXPECTING FAIRLY BREEZY NORTHWEST WINDS IN THE 15-25MPH RANGE WITH
HIGHS ONLY TOPPING OFF IN THE UPPER 60S TO TO LOWER 70S.
MORE EARLY FALL-LIKE CONDITIONS ARE THEN EXPECTED INTO THE WEEKEND
AS CANADIAN HIGH PRESSURE DOMINATES THE CENTRAL CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. LOOK FOR MOSTLY CLEAR SKIES
THROUGH SUNDAY WITH HIGHS SATURDAY AND SUNDAY IN THE 70S AND
OVERNIGHT LOWS IN THE 40S TO LOWER 50S.
FOR MONDAY THROUGH WEDNESDAY...DEEPENING CYCLONIC FLOW OVER CANADA
AND NORTHERN CONUS WILL DRIVE A COUPLE TROUGHS THROUGH THE REGION FOR
A PERIOD OF UNSETTLED WEATHER WITH ON/OFF SHOWER AND THUNDERSTORM
CHANCES. TEMPERATURES ARE EXPECTED TO BE AT OR A FEW DEGREES BELOW
NORMAL WITH HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1230 PM CDT THU SEP 4 2014
STRONG CAP IN THE 800-700 MB LAYER WORKS ACROSS THE AREA THIS
AFTERNOON INTO THE EVENING...AND LOOKS TO BE A STRONG ENOUGH
INHIBITOR TO PREVENT CONVECTION. SOME MVFR CIGS CURRENTLY ASSOCIATED
POST AN OUTFLOW BOUNDARY SINKING SOUTH ACROSS KRST/KLSE...MORE AMPLE
COVERAGE NEAR KLSE. WITH THE INVERSION EXPECTED TO HOLD THROUGH THE
AFTERNOON...THE MVFR CLOUDS COULD FOLLOW SUIT. WILL HOLD SOME MVFR
CIGS THROUGH AT LEAST MID AFTERNOON - BUT COULD BE NEEDED LONGER.
MESO MODELS PROVIDING A VARIETY OF SOLUTIONS ON WHERE/WHEN
CONVECTION COULD REFIRE THIS AFTERNOON AND EVENING. CONFIDENCE LOWER
AS A RESULT. THAT SAID...GOING TO PUT FAITH IN THE STRONG LOW LEVEL
WARMING/CAP WHICH WILL NEED AN APPROACHING COLD FRONT TO THE WEST TO
PROVIDE A SHOWER/STORM THREAT. SOMEWHERE IN THE 02-04Z TIME FRAME
LOOKS TO BE THE MOST FAVORABLE TIME FOR PRECIPITATION.
ANTICIPATE CHANGES TO THE FORECAST AS THE CONVECTIVE TIMING/COVERAGE
BECOMES CLEARER.
CLOUDS LIKELY TO HANG AROUND POST FRONT THROUGH FRI MORNING...BUT
APPEAR TO BE THE MID/UPPER LEVEL VARIETY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATED.....RIECK
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK